This PDF file contains the front matter associated with SPIE Proceedings volume 7508, including the Title Page, Copyright information, Table of Contents, Introduction, and the Conference Committee listing.

A brief review of recent progress made in a range of in-fiber integrated interferometers for measuring is presented, with particular attention paid to the multi-core based in-fiber integrated techniques, which have the potential to be exploited in a variety of wide applications.

The cavitation erosion by laser-induced bubble collapsing near solid boundary is investigated employing a new force sensor together with a hydrophone. The experimental results indicate that liquid-jet formation and acoustic transient emission are both predominant features on the cavitation erosion; both the liquid jet and the acoustic transient play a vital role in the erosion mechanism during the first two stage of bubble collapse. Finally, the erosion mechanism during the first two collapse of the cavitation bubble is summarized and presented.

Slot waveguide structure gained attention due to high confinement of power inside low index slot region. The high efield confinement is dependent upon various geometrical parameters. A double slot structure where two low index slots of hard material in high index cladding of compressible material is proposed. Power confinement factor dependency upon distance between low index slots has been numerically computed. Sufficient numerical results obtained lead to the proposal of opto-mechanical sensor based upon proposed double slot structure.

Since the advent of slot optical waveguides by Lipson, normally SOI based slot optical waveguides have been under consideration. It has been found that glass based slot optical waveguide structures, where refractive index contrast ratio is comparatively less can also play important role in forming complex nano size optical devices. We have made use of power confined inside low index slot region for a double slot structure, where central high index slab is acting as a cantilever. Novel optomechanical sensor has been proposed based on variation in power confined inside low index slot region due to the movement of central high index slab under the action of external force (temperature, pressure, humidity, etc.)

An all-fiber liquid level sensor based on core-offset attenuator is proposed and demonstrated. The interference fringe is affected by the fraction of the length of the interferometeric arm that is surrounded by the liquid. The experiments show that for a liquid level variation of 30mm, the maximum difference of attenuation changes about 3dB. Also in the linear region, a sensitivity of 0.84dB/mm is achieved. For a temperature range from 30°C to 80°C, the measured liquid level fluctuates less than 1% without any temperature compensation. The liquid level sensor we reported in this paper appears more robust and repeatable, and its ease of fabrication makes it a low cost alternative to existing fiber liquid level sensor.

Fiber optical evanescent field sensors provide means of optical power sensitive to temperature. This paper proposed a novel and practicable fiber optical temperature sensor with doubly cladding structure. It worked on the basis of optical attenuation brought about by the outer cladding medium with a large thermooptic coefficient. As the external diameter of the sensing section was less than 1mm, the sensors were sensitive to the temperature of ambient air. The doubly cladding fiber optical sensors with different fabrication characteristics (basically length and the diameter of inner cladding of the sensing section) and external medium were studied experimentally. The sensor obtained by an outer cladding of Dow Corning OE-4110 showed a low insertion loss of -0.7dB, a peak value of power loss of -66dB at 51°C, and a linear dynamic range of -53dB for a temperature interval of 5°C at 1550nm. The sensor obtained by SILRES^®Ren60 had the peak value of power loss at about 105°C and a temperature interval of 65°C in a linear dynamic range of -5 dB.

Performance degeneration of FBG directly affects the long-term stable work of the whole FBG sensing network. According to the formula of FBG refelectd spectrum,the impacts of refraction index modulation depth Δn on refelectd spectrum peak and zero bandwidth are deeply analysed. Based on the theoretical analysis of energy level transition theory, we can find that the temperature shock can make electrons in traps which is of certain distribution of energy overflow,and then cause the reduction of modulation depth Δn , and eventually lead to the performance degeneration of FBG. Conducted the high-low temperature cycling degenerate experiment of FBGs, experimental results show temperature cycling alternate shock will produce accelerated aging phenomenon:after 1000 alternating cycles, the reflection spectrum is almost difficult to identify, the sensing ability is basically lost. Test results prove the correctness of theoretical analysis.

We introduce a modal wave front sensing technique of using binary computer generated hologram (BCGH) and a coding approach. Several types of Zernike aberrations were encoded into the BCGH using this method. Light wave front was modulated by BCGH and single Zernike aberration mode respectively, and the holographic modal wavefront sensor was simulated and verified. The results show that, wave front distorted by a special aberration mode, after modulated by the BCGH, can be transformed into beams which have a relative intensity, which can reflect the change trend of the aberration coefficients in the unknown wavefront.

The target of this paper is to design a novel water-vapor sensor used in humidity transducer system based on high-quality factor (Q) spherical microcavities, which at present obtained the highest Q value induced by surface tension. Sensitive mechanics and its high sensitivity are discussed according to optical loss sensitization to coupling system composed of a microsphere cavity and a tapered fiber. After that, fabrication methods of master parts of the sensor in our lab are introduced. Additionally, a sensing structure composed of a gas-chamber and a vacuum-chamber is also designed. According to water absorption band, telecom band around 1550nm is used to pump the microsphere optical mode. In a vacuum environment, a transmitted spectrum is obtained through output end, revealing some information about the core system including the size of the microcavity and the optical loss of the regime. However, when the core system is placed in a water vapor environment, the transmitted spectrum will change due to extra optical loss induced by water molecules absorption, behaving as spectral shift, free spectrum range (FSR) or line width broadening. Contrasting and analyzing two different spectrums in the two situations, the gas concentration can be deduced. Indispensable experiments were also carried out, showing that, the two spectrums are different from resonance hump, formant strength and formant line width. Even an ultra low water vapor concentration induced a measurable output signal, ensuring a high detecting sensitivity. Certainly, the analyted vapor should not only be water vapor. This kind of sensitive mechanics is versatile. Changing the pumping light corresponding to the analyted absorption band, we are able to detect a series of vapor.

According to the experimental results of side polished fiber (SPF), a three dimensional optical waveguide model with longitudinal side polished transition zones is built. Based on the model, characteristics of optical transmission are calculated and analyzed by three dimensional finite differential beam propagation method. The model describes the optical transmission characteristics because the calculation based on the model is fitted well with the experiments. The calculation shows that the length of side polished area affects the optical attenuation of optical fiber, but the attenuation does not increased monotonically with the length when the length is less than certain value. The relationship between optical attenuation of SPF and the thickness of residual side polished cladding is not a monotonic one as well. The refractive index of overly on the side polished area has much more effect on the optical attenuation. Both width and thickness of overlay on the side polished area cause the oscillated change of optical power attenuation in the fiber core.

Resonant sensors have many advantages such as high sensitivity, long term stability and easy interfacing with digital signal processing. In this paper, we design and realize a resonant mass sensor. In order to get resonator of high Q value, tapered and thin oscillating tube is designed as the oscillator. Self-excited oscillation mode and closed-loop driving circuit is used, which enables the oscillating frequency stabilize in the natural frequency of the oscillator. Meanwhile, automatic gain control circuit is designed to keep constant amplitude of oscillating. Finally, this mass sensor achieve successful in measurement of concentration of aerosol. The experimental results show that the mass sensor takes advantages of compact structure, high precision and high reliability.

Power line inspection and maintenance already benefit from developments in mobile robotics. This paper presents mobile robots capable of crossing obstacles on overhead ground wires. A teleoperated robot realizes inspection and maintenance tasks on power transmission line equipment. The inspection robot is driven by 11 motor with two arms, two wheels and two claws. The inspection robot is designed to realize the function of observation, grasp, walk, rolling, turn, rise, and decline. This paper is oriented toward 100% reliable obstacle detection and identification, and sensor fusion to increase the autonomy level. An embedded computer based on PC/104 bus is chosen as the core of control system. Visible light camera and thermal infrared Camera are both installed in a programmable pan-and-tilt camera (PPTC) unit. High-quality visual feedback rapidly becomes crucial for human-in-the-loop control and effective teleoperation. The communication system between the robot and the ground station is based on Mesh wireless networks by 700 MHz bands. An expert system programmed with Visual C++ is developed to implement the automatic control. Optoelectronic laser sensors and laser range scanner were installed in robot for obstacle-navigation control to grasp the overhead ground wires. A novel prototype with careful considerations on mobility was designed to inspect the 500KV power transmission lines. Results of experiments demonstrate that the robot can be applied to execute the navigation and inspection tasks.

The theoretical model and calibration experiment of biological compact disc sensor (BioCD) is presented. BioCD is a new kind of label-free optical biosensor based on Interferometry to detect immobilized biomolecules with high speed, high sensitivity and high-throughput. Output signal theoretical expressions were deduced. The influences of illuminating beam Gauss parameter and lens aberration to detection sensitivity were simulated. Simulation result showed that Gauss parameter as well as aberration parameter increase will reduce detection sensitivity. Then BioCD experimental platform was setup, sensor arrays for calibration was fabricated using reactive ion etching technology on silicon substrate. Experimental results indicated that detection sensitivity can achieve 15mV/nm.

The measurement technology of pH is essential in seawater desalination. Glass electrode is the main pH sensor in seawater desalination. Because the internal impedance of glass electrode is high and the signal of pH sensor is easy to be disturbed, a signal processing circuit with high input impedance was designed. Because of high salinity of seawater and the characteristic of glass electrode, ultrasonic cleaning technology was used to online clean pH sensor. Temperature compensation was also designed to reduce the measurement error caused by variety of environment temperature. Additionally, the potential drift of pH sensor was analyzed and an automatic calibration method was proposed. In order to online monitor the variety of pH in seawater desalination, three operating modes were designed. The three modes are online monitoring mode, ultrasonic cleaning mode and auto-calibration mode. The current pH in seawater desalination was measured and displayed in online monitoring mode. The cleaning process of pH sensor was done in ultrasonic cleaning mode. The calibration of pH sensor was finished in auto-calibration mode. The result of experiments showed that the measurement technology of pH could meet the technical requirements for desalination. The glass electrode could be promptly and online cleaned and its service life was lengthened greatly.

Pumping a single-mode, tunable, external-cavity laser to excite the whispering gallery modes (WGM) of micro ring resonators (MRRs), a series of equidistant, wide free spectrum range (FSR) can be observed. Frequency shift of FSR can be used to feedback external changes, making MRR very promising in high-sensitivity sensing. In this paper, a novel displacement sensor composed of a micro ring resonator and a waveguide is presented and a designing route for this sensor is discussed. Based on mathematical analysis and the beam propagation methods (BPM), the major parameters including the geometry of MRR and micro cantilever are investigated in detail. Materials selection and fabrication method under current processing technic are also presented. For the typical structure in this paper, the final Q factor is estimated approximately 103 in theory at the wavelength of 1.5μm.Displacement alteration of cantilever is 0.296x10^-6m - 0.535x10^-5m approximately corresponding 10-8-10-6N force loading. The shift of transmission spectrum is about 3.9nm versus perimeter of MRR changing 1μm.

According to the experimental force of optical fiber in an earth dam model, an analysis model of fiber embeded in an earth dam is set up using ansys 9.0 software. Stress analysis of optical fiber in dams becomes easy after the boundary conditions is simplified. The deformation of optical fiber under different pressure loads are calculated. The relationship between the stress and the weight applied to the optical fiber is obtained while the settlement occurred in the dam model, even badly collaps happened. The relationship between the depth of the optical fiber away the top of the dam model and the sensitivity of optical fiber to applied loads is described.

Aim at the force of optical sensing cable for a distributed optical fiber sensing monitoring system applied in embankment dams, a loading apparatus is designed. The apparatus is to simulate work condition when the optical sensing cable is in use. Some grooves with different angles at the bottom of loading board of the apparatus are set to perform variety of forces applied to the optical sensing cable under the loading board. The groove angles represent different direction of the force in the embankment dams. The commercial finite element analysis software Ansys9.0 is applied to analyze the deformation of the optical cable in loading experiments. The results of analysis are helpful to guide the experiment in the next step.

In order to measure inner surface roughness of small holes nondestructively, a new fiber optic sensor is researched and developed. Firstly, a new model for surface roughness measurement is proposed, which is based on intensity-modulated fiber optic sensors and scattering modeling of rough surfaces. Secondly, a fiber optical measurement system is designed and set up. Under the help of new techniques, the fiber optic sensor can be miniaturized. Furthermore, the use of micro prism makes the light turn 90 degree, so the inner side surface roughness of small holes can be measured. Thirdly, the fiber optic sensor is gauged by standard surface roughness specimens, and a series of measurement experiments have been done. The measurement results are compared with those obtained by TR220 Surface Roughness Instrument and Form Talysurf Laser 635, and validity of the developed fiber optic sensor is verified. Finally, precision and influence factors of the fiber optic sensor are analyzed.

Jet Propulsion Lab and Vescent Photonics Inc. are jointly developing an innovative ultra-compact (volume < 10 cm³), ultra-low power (<10^-3 Watt-hours per measurement and zero power consumption when not measuring), completely nonmechanical electro-optic Fourier transform spectrometers (EO-FTS) that will be suitable for a variety of remoteplatform, in-situ measurements. This EO-FTS consists of: i) a novel electro-evanescent waveguide architecture as the solid-state time delay device whose optical path difference (OPD) can be precisely varied utilizing voltage control, ii) a photodetector diode, and iii) an external light/sample collecting devices tailored for either in-situ gas and/or rock sample analysis or for remote atmospheric gas analysis. These devices are made possible by a novel electro-evanescent waveguide architecture, enabling "chip-scale" EO-FTS sensors. The potential performance of these EO-FTS sensors include: i) a spectral range throughout 0.4-5 μm (25000 - 2000 cm-1), ii) high-resolution ▵λ ≤ 0.1 nm), iii) high-speed (< 1 ms) measurements, and iv) rugged integrated optical construction. This performance potential enables the detection and quantification of a large number of different atmospheric gases simultaneously in the same air mass and the rugged construction will enable deployment on previously inaccessible platforms. In this paper, the up-to-date EO-FTS sensor development status will be presented; initial experimental results will also be demonstrated.

The development of a fibre optic oxygen sensor system based on an unsymmetrical fibre coupler for the measurement of oxygen partial pressure (PO2) is reported. The principle of the oxygen sensor is based on the luminescence quenching of a luminophore by oxygen and the sensor consists of an unsymmetrical silica fibre coupler and a PMMA sensing medium that contains immobilized Pt (II) complexes. The 2x2 unsymmetrical optical fibres coupler was made using two silica fibres with different core diameters, one is with 200μm core diameter and another one is with 105μm core diameter. In our current work, the fibre coupler fibre was optimized to improve the performance of the sensor system by increasing light coupling efficiency from LED to sensor probe. The performance of the fibre optic oxygen sensors was evaluated using Ocean Optics spectrometer (USB2000) based on the luminescence intensity measurement. The details of the sensor chemistry, experimental system and the results were presented. As result, a special fibre coupler has been used to construct a practical, low cost oxygen sensor.

In this study we present a method to sort measured-data and process signal for special hydrodynamic monitoring system based on distributed optical fiber sensors. The procedure consists of defining the attribute of the data, data processing and information matching. The data of for-processing-part are processed regularly, which directly provides results for the user from the monitoring system. These results go into the next step to add environmental parameters, which includes weather, special events and season information. Information fusion and matching operation of the result and environment information enhances the accuracy of hidden hazard early warning.

This paper presents a novel temperature sensor based on bimetallic strip and optical fiber microbending loss. A bimetallic strip is a mechanical temperature sensor element, is simply constructed from two strips of different metals with different thermal linear expansion coefficient bonded together. A fiber is distorted in a deformer by pressing it between grooved plates. One end of the bimetallic strip is welded on a fixed framework, the other end performed upon the deformer, and form a microbending optical fiber temperature sensor. When the temperature changes, the thermo static bimetallic strip deforms, and causes grooved plates having a displacement according to the temperature changes, and modulates light loss in fiber. The measuring results show measuring range comes to around 100°C with high accuracy and linearity.

The chemical oxygen demand(COD) in Seawater is an organic contaminant synthetical indicator and one of the most important ocean environment monitoring items. At present, the marine pollution in China is serious day by day, but the traditional COD measurement method can not meet demand. It is essential to research the real-time monitoring system with no time delay, no reagent application and no secondary pollution. The basic principles of analytical techniques and a real-time monitoring system for the measurement of seawater COD were described in this paper. The basic principles were based on the ultraviolet absorbency degree analytical method. The correlation between ultraviolet absorbency degree and COD in seawater was studied in this paper. The result showed that under certain condition, it could calculate COD value from ultraviolet absorbency degree. A novel seawater COD sensor was designed in this paper, and it could circularly lead in the seawater cleaning out the contamination.

Surface Plasmon Resonance (SPR) is very sensitive to the change of the refractive index of the dielectric medium on metallic films. Without labeling and purification the samples can quickly, real-timely and dynamically analyze bio-molecular interactions. The biochip detection system based on SPR has been established to detect the immunoreactions for the prepared bFGF protein chip, including the reaction between bFGF antigen and antibody, between bFGF antibody and antibody's antibody respectively. After the immunoreactions occur on sample arrays the refractive index as well as the resonant angle will increase. The reflected light images of the chips taken by the CCD camera can determine the happening of the immunoreactions on the probes of the chips and the existing of substances that are needed to be detected. SPR system can analyze qualitatively and quantitatively.

In this paper, the transposition process of the polarization of light state is described by the Stokes-Mueller formula, according to which the depolarized capability of the p-polarized light by rough surfaces is discussed. The values of M₁₁/M₀₀ in Mueller matrix of the typical targets' surfaces are measured by experiment. The results indicate that the value of M₁₁/M₀₀ decreases with the increasing of surface roughness, which implies that the depolarized capability of the p-polarized light increases. Besides, the values of M₁₁/M₀₀ of metal targets are larger than 0.61, while the values of camouflage cloth, wooden plates and cement boards are all less than 0.3, which provides a possible way to detect metal targets by polarization imaging.

ALOS is a high performance satellite sensor; the visible spectrum component can replace SPOT imagery. The paper fuses ALOS image with wavelet transform and local deviation. Wavelet transform can decompose image into low-frequency part and high-frequency part, condition manner will discard the low-frequency part or high-frequency part, and so the fusion result is general. Local deviation can hold low-frequency information, and associate the high-frequency information of multispectral and panchromatic image. The result shows that wavelet transform with local deviation can improve the performance of fusion image.

An image acquisition system is introduced, which consists of a color CMOS image sensor (OV9620), SRAM (CY62148), CPLD (EPM7128AE) and DSP (TMS320VC5509A). The CPLD implements the logic and timing control to the system. SRAM stores the image data, and DSP controls the image acquisition system through the SCCB (Omni Vision Serial Camera Control Bus). The timing sequence of the CMOS image sensor OV9620 is analyzed. The imaging part and the high speed image data memory unit are designed. The system structure and its application of CMOS image sensor OV9620 in paper currency number recognition are also introduced. The hardware and software design of the image acquisition and recognition system is given. In this system, we use the template matching character recognition method to guarantee fast recognition speed and high correct recognition probability.

Battery Monitoring's basic function is to monitor battery status. It can be able to timely report the states to user in order to maximize using of battery storage capacity and cycle life. We use 1-wire bus digital sensor. The sensor is DS2438.It can detect voltage, current, power consumption and temperature of the battery. 1~Wire Bus is a technology that it can communicate with the peripheral only with one line. This can greatly save system resources. Digital sensors integrates A/D conversion and the measured data is the digital traffic. This can improve system integration, simplify the circuit.

The impact on the measurement accuracy caused by uncollimated illumination beam during the process of human eye aberration measurement by using Hartmann-Shack wavefront sensor has been studied. The principle of Hartmann-Shack wavefront sensor has been introduced. The diopter curve corresponding to the installation errors of lens has been calculated. And the according curve reveals that the diopter of illumination beam at the section of entrance pupil is quite sensitive to the installation errors of lens. The impact on wavefront at the exit pupil under the illumination of uncollimated beam has been analyzed and relative experiments have been done. The experiments show seldom impact of it. Quantitative relationship between the precision of ocular aberration measurement and installation errors of lens is proposed. Experiments to quantitatively simulate the installation errors have been done. The experimental results are in accordance with the theoretical analysis we made and the collimation of illumination beam has an obvious and direct influence on the measurement precision of ocular aberration.

Wavefront curvature sensor has been used in the field of adaptive optics and optical metrology. But the application is generally based on the assumption that the intensity and wavefront of the incident light is uniform distributed, which is disaccord to the basic principle of curvature sensing technology. The theoretical analytic expression of wavefront curvature signal got from sensors for the non-uniform incident light is work out with the mean according to Fourier optics theory. The numerical analysis of curvature signal deviation for uniform wave and Gaussian wave has been done using the signal expression under uniform and non-uniform intensity. The result of analysis indicates that the deviation of wavefront curvature sensor sign appears under uniform wave and Gaussian wave. When the phase distribution is 4^th Zernike polynomials, the deviation is the most. The deviation reduces as the order of Zernike polynomials increases.

A quasi-distribution optic fiber sensor system based on general optic fibers is presented, in view of the characteristics of the ordinary optical fiber which is low-cost, adaptable environment and more conducive to the realization of large-scale and large-scale application than the special fiber. The principle of fiber sensor is introduced. Then, the solution temperature experiment and concentration experiment are carried; the curves of the fiber loss changing with the solution temperature and concentration are gained, which are good agreement with expectation value.­

The basic principle of wavefront curvature sensor (WFS) is described, and the strongpoints and shortcomings of traditional schemes are analyzed. As a novel WFS, the wavefront curvature sensor comprising a diffraction grating (DGWFS), which consist a defocus grating and lens, and can measure the light intensity distribution at the two defocused spots simultaneity, has the advantage of realization easily, adjustment expediently, low cost, and so on. The DGWFS has a wide application in astronomy, measurement, laser, optical component testing etc. Its principle is analyzed. Two kinds of phase retrieval arithmetics of wavefront curvature sensor are analyzed by comparison. Besides, the latest applications of wavefront curvature sensor are generally presented. Finally a novel method for measurement on solid-state laser thermal lens utilizing DGWFS is presented.

The fast steering mirror is a significant element of the photoelectric precision tracking system and is mainly used for attenuating the tracking error of the main axis and rejecting the line-of-sight jitter caused by various disturbances. A control loop model is constructed and object parameters have been identified according to this model in this paper. Low sampling frequency introduce great delay into the imaging tracking system, which may restrict greatly the closed-loop bandwidth, reduce tracking precision of the system and even make the system unsteady. Various elements which limit tracking loop bandwidth are presented and analyzed. Three tracking systems with different sampling frequency are simulated and analyzed. From the simulation result the conclusion can be drawn that it is difficult to increase the closedloop bandwidth in the presence of great delay by means of the general control method. Accordingly feedback control or feed forward control may be tried to improve the error attenuation of the system. The micro-mechanical gyro can be used for measuring the angular velocity of fast steering mirror, so output of velocity gyro as velocity loop feedback may improve the system performance. Furthermore, the velocity loop feedback can enhance the rigidity and the output stability of the tracking system. Finally, the velocity feedback can increase the type of the open loop system; consequently it will improve the error attenuation of the system. The simulation result shows that the tracking precision of the system with velocity feedback is 10 times better than the system without velocity feedback.

In this paper, to investigate a method improving high temperature response characteristics, the high temperature sensing properties of fiber Bragg gratings packaged by the red copper and cuprum and aluminum respectively were studied. The results indicate that the response characteristics of FBG have very good linearity, and the linearity of FBG packaged by aluminum is best, but its response time is slower because of lower heat conductivity of packing material, and that higher thermal expansion coefficient of packaging base material can effectively reduce the nonlinearity of FBG sensor in high temperature environment. At last, a method improving the temperature sensitivity of FBG sensor and reducing FBG's nonlinear response versus temperature was presented, and packaging material is selected according to response time versus temperature change.

We present a new magnetic field sensor based on D-shaped long-period fiber grating (D-LPFG). Iron thin-film was coated on the polished surface of an LPFG to function as a sensing head. Different levels of magnetic field caused a shift in the grating loss-dip wavelength shift. The sensing section of a D-LPFG causes a change in the effective refractive index both of the core mode and co-propagation cladding modes in response to the different levels of the applied magnetic field. The maximum shift in wavelength of 36 nm was obtained in the case of a magnetic field of 153 kA/m.

The modulated coupled infrared light is injected into the liquid drop by a source fiber positioned in the drop head and is collected by a detector fiber on the opposite side after various reflection, refraction and absorption of the optical signal inside the drop. Capacitive drop sensor uses the drop head as one of its plate and a cylindrical ring plate, which surrounds the drop head and the space occupied by the formed drop, as another. Based on the capacitance changes, the instant drop volume can be obtained during its growth. Fiber-capacitive drop sensor will be introduced concretely in this paper, including its working principle, mathematical model, and the structure design of drop head.

A bottom contact organic field effect transistor (OFET) was fabricated with poly(3-hexylthiophene) (P3HT) as the channel semiconductor. P3HT thin film was deposited onto a SiO₂/n-Si substrate by spin coating and electrical characteristics of the P3HT-FET were investigated in a nitrogen flux. A change in the saturation drain-source current (IDS) was observed when device was exposed to different concentrations of nitrogen dioxide (NO₂) gas. It was found that the variation in the IDS was remarkable with NO₂ injected in a short time.

This paper described a procedure based on electrospinning for generating nanofibers with controllable diameters and morphology. When an acetone and N,N-dimethylacetamide (DMAc) mixture solvent containing poly(vinylidene fluoride) (PVDF) was injected through a needle under a strong electric field, nanofibers made of PVDF formed as a result of electrostatic jetting. To control the diameter and morphology of PVDF nanofibers, the solution properties and process parameters were investigated, such as polymer concentration, the ratio of the mixture solvent, feeding rate, applied electric field, and needle-to-collector distance. The fabricated fibers were 30-8000 nm in diameter. The increase in the polymer concentration caused an increase in the fiber diameter. However, the increase in the feeding rate and applied electric field decreased the fiber diameter. Variation in the needle-to-collector distance did not result in significant changes in the fiber diameter. The ratio of the solvent also had a very significant impact on electrospinning. The diameter and morphology of the PVDF nanofibers were characterized by optical microscope and scanning electron microscope (SEM).

Vibration monitoring characteristic of fiber Bragg grating (FBG) sensor and resistance strain gauge sensor were investigated. FBG sensor and resistance strain gauge sensor were fixed on a uniform strength beam. The advantage and disadvantage of two kinds of sensors were compared. Vibration was caused by a motor which was fixed at the end of uniform strength beam. The vibration signal in time domain was measured by FBG sensor and resistance strain gauge sensor simultaneously. And the frequency spectrum of the vibration signal was acquired through Fast Fourier Transform (FFT). The results show that, the vibration graph in time domain monitored by FBG sensor is consistent with the vibration graph monitored by resistance strain gauge sensor. The frequency spectrum of FBG sensor displays second harmonic and third harmonic obviously, except fundamental frequency. But the frequency spectrum of resistance strain gauge sensor displays no higher harmonic. It is also indicated that, under the electromagnetic interference conditions, the vibration signal can not be monitored by resistance strain gauge, but can be monitored by FBG sensor.

Cavity ring-down laser absorption spectroscopy is a sensitive, accurate way to acquire weak optical absorption spectra. The ring-down time is independent of light intensity, as is typical in most other forms of laser spectroscopy. According to the law of Beer-Lambert, the new continuous wave laser gas concentration measurement system based on the cavity ring-down is introduced. The ring-down time-gas absorption coefficient-gas concentration relation and the loop loss-gas absorption coefficient-gas concentration relation are analyzed and the measuring model is established. Avoid the aerosol scatter and Rayleigh scatter affect the measuring results. Accept nonlinear differential tunable laser source to increase the tuning range. Then, the ring-down times of three certain lights in three corresponding gases with the same concentration were obtained, and the gas absorption characteristics in different concentrations are given. The research proofs that the cavity ring-down based on nonlinear difference frequency theory is an effective method for trace gas measurement and analysis.

Unattended laser target designator (ULTD) was designed to partly take the place of conventional LTDs for accurate positioning and laser marking. Analyzed the precision, accuracy and errors of acoustic sensor array, the requirements of laser generator, and the technology of image analysis and tracking, the major system modules were determined. The target's classification, velocity and position can be measured by sensors, and then coded laser beam will be emitted intelligently to mark the excellent position at the excellent time. The conclusion shows that, ULTD can not only avoid security threats, be deployed massively, and accomplish battle damage assessment (BDA), but also be fit for information-based warfare.

The tradition method of detecting precision of Rational Function Model(RFM) is to make use of a great deal check points, and it calculates mean square error through comparing calculational coordinate with known coordinate. This method is from theory of probability, through a large number of samples to statistic estimate value of mean square error, we can think its estimate value approaches in its true when samples are well enough. This paper is from angle of survey adjustment, take law of propagation of error as the theory basis, and it calculates theory precision of RFM localization. Then take the SPOT5 three array imagery as experiment data, and the result of traditional method and narrated method in the paper are compared, while has confirmed tradition method feasible, and answered its theory precision question from the angle of survey adjustment.

A new fiber-optic microphone was demonstrated theoretically and experimentally in this paper. The microphone is based on Mach-Zehnder and Sagnac interferometers, which comprise an amplified spontaneous emission (ASE) light source, a conventional single-mode fiber, a fiber reflector and two 3dB couplers. As two light paths have the same optical length but travel different sequence paths in this hybrid interferometer, the beams in different paths pass through the sensing fiber at different times and the phase signals differ from each other. Utilizing the two light paths interfered and fiber waveguide modulator replaced by piezoelectric ceramic (PZT) modulation, to implement the direct acquiring of weak voice signals. Adoption of the ASE light source and the single-mode fiber as sensing fiber decreases the system cost. The application of the fiber waveguide modulator overcomes the limitation in high frequency and nonlinear effect of PZT modulation, improves the flexibility of the system and the frequency response range. Phase shifts of the two interfered beams, which is caused by the slowly varying environmental parameter, is equal to eliminate the influence from outside effectively. In this system, the signal demodulation circuit based on weak voice signal is simpler than the PGC demodulation circuit. The experimental results of the fiber-optic microphone based on waveguide modulator have been demonstrated that the simple circuit demodulation for the weak voice signal is feasible.

Based on the Michelson interferometer, we use the circulator to realize the dual-path detection of the vibration signal, which reduce the intensity noise caused by laser source. Reflectors are connected to the terminal of the signal arm and reference arm respectively. The phase generated carrier (PGC) technology should use piezoelectric ceramic (PZT) to generate carrier signal with high frequency in traditional demodulation techniques. Whereas the PZT is sensitive to the external environment changing, so accuracy of vibration measurement will fall down, in order to solve this problem the fiber waveguide modulator was used in the system instead of PZT. Then we use arctangent algorithm instead of PGC algorithm to demodulate the signals, which could greatly simplify the algorithm. The output of the signals are input into the computer through the data acquisition card and then demodulated by arctangent algorithm compiled by Labview. Theoretical analysis and experimental prove the phase orthogonality of the two output signals, the amplitude and frequency of the vibration signal can be detected at the same time. The Experiment results indicate that the system can demodulate the vibration signal accurately.

In this paper, we study a novel chemical gas sensor based on polymer-carbon black composites for NO2 gas-sensing application. The polymer which is made of polyhexylthiophene mixed with carbon black is employed as the sensing material which is immobilized on the interdigitated microelectrode pair. The electric resistance changes of the sensor to NO₂ at different concentrations have been examined. Also the effect of the humidity to the sensor was examined. The results show that the resistance of the sensor decreases with the NO₂ concentration rising, and it's not sensitive to the humidity.

Experimental investigations on three different sunlight captures with diameter 150mm, 212mm, 300mm were carried out under different conditions such as sunny conditions, cloudy conditions and overcast conditions and the two different size solar light pipes with diameter 360mm and 160mm under sunny conditions. The illuminance in the middle of the sunlight capture have relationship with its size, but not linear. To improve the efficiency of the solar light pipes, the structure and the performance of the sunlight capture must be enhanced. For example, University of Science and Technology Beijing Gymnasium, Beijing 2008 Olympic events of Judo and Taekwondo, 148 solar light pipes were installed with the diameter 530mm for each light pipe. Two sunlight captures with different shape were installed and tested. From the measuring results of the illuminance on the work plane of the gymnasium, the improvement sunlight captures have better effects with the size of augmenting and the machining of the internal surface at the same time, so that the refraction increased and the efficiency of solar light pipes improved. The better effects of supplementary lighting for the gymnasium have been achieved.

Chemical gas sensor that utilizes poly (2-vinypyridine)-carbon black composition as sensitive film is studied. Poly (2-vinypyridine)-carbon black was deposited on the interdigital microelectrodes via spin-coating method to detect organic vapor and humidity. To study the influence of the carbon black, poly (2-vinypyridine)-carbon black composites with different carbon black content were compared. The various characteristics such as sensitivity and selectivity of poly (2-vinypyridine)-carbon black based sensor have been studied. The results show that proper carbon black content and modified carbon black can improve the sensors' response characteristics.

VOx/TiOx/Ti multilayer thin films were deposited on glass and molybdenum substrates by magnetron reactive sputtering. The structure and properties of thin films were measured with X-ray diffraction (XRD), QJ31 Wheatstone Bridge and the internal friction instrument. Preparing process and internal friction of VOx/TiOx/Ti multilayer thin films were studied respectively. On the basis of measurement analysis from crystal structure, the curves of resistance vs temperature, and Young's modulus vs temperature, the phase transformation of VOx multilayer thin film occurs at 66°C and its temperature coefficient of resistance is - 4.35%/°C.

The performance of square silver nanoprisms arrays for molecular sensing applications is studied by the Finite Difference Time Domain (FDTD) method. The result shows that the electromagnetic coupling between the nanoparticles can be optimized to increase the sensitivity. Especially, arrays with the highest extinction and the sharpest resonance bandwidth are found to be more than 100 nm/RIU refractive index of sensitivity compared with the single particle. The result of study can offer some valuable guidance to the properties of localized surface plasmon resonance sensor with nanoparticles arrays how to be improved. This nanoparticle array with high sensitivity holds a great potential in the applications as biochemical sensor based localized surface plasmon rensonance.

The different N-doped ZnO thin films were grown by RF magnetron sputtering on the glass substrates by changing the ratio of O₂ to N₂.The XRD and photoluminescence (PL) spectra were measured. The results show that the intensity and positions of these PL peaks are changed with nitrogen content. There are two peaks at 374nm and 391nm under fluorescence spectrum when the ratio of Ar:O₂:N₂ is 15:7:8. The fluorescence peak located at 374nm has the characteristic of p-type ZnO films.

Simultaneous measurement of the bending curvature and axial stress by using dual fiber Bragg gratings and a sidepolished technique is presented. Curvature measurement, using side-polished fiber Bragg gratings with different thicknesses ranging from 93.94 to 70.66 μm shows corresponding sensitivities from 0.096 to 0.402 nm/m^-1 for bending curvatures in the range of 0 - 3 m^-1. The simultaneous axial stress is measured based on the shift in the Bragg wavelength and ranges from 0.008 - 0.128 GPa. A maximum sensitivity of 13.83 nm/GPa is demonstrated.

Hydroxyl group is important for the sensitivity and selectivity of never agents sensors. A new hydrogen bond acidic polymer poly(3,4-dihydroxythiophene) are synthesized from EDOT(ethylene dioxythiophene) by two steps. This material are characterized by UV-vis spectra and FT-IR spectra. The polythiophene polymers with hydroxyl groups are obtained. Composite materials are prepared as films on QCMs (Quartz Crystal Microbalance) and quartz substrates by Spin-coating. The result shows that poly(3,4-dihydroxythiophene) is a sensitive material with good selectivity and adsorbability to organophosphorous vapors.

Over the last few years, fiber Bragg grating (FBG) sensors have attracted a lot of interest and they are being used in various applications. This paper describes the FBG sensors used for strain monitoring of bogie and other steelworks. FBG sensors and resistance strain gauges are set on different position of steel girder, and weight is loaded on the steel girder. Strain value of the steel girder can be caught by two kinds of sensors when weight loaded is changed. Result of experiment shows that strain value obtained by resistance strain gauges and FBG sensor is coinciding. There is a linear correlation between value of strain and the weight loaded on the steel girder. FBG sensors with different encapsulations are set on bogie by acrylic plastic materials in order to monitor its dynamic strains. When sinusoidal load with its frequency from 0.15Hz to 2Hz was set on the bogie, FBG sensor system with data sampling rate of 20Hz were used to monitoring the dynamic strains. Strain data caught by FBG sensor system can offer accurate description of dynamic strain, and value of strain provided by FBG sensor suits theoretical values well. The experimental observations show that FBG sensors can be set on steelworks easily, and can monitor both static strain and dynamic strains well.

The π phase-shifting technique have used early to remedy frequency aliasing in Fourier transform profilometry , two deforming stripe of phase difference π is photographed and then subtracted to remove the influence of zero frequency and high frequency. Due to background of measured object represent zero frequency of deforming stripe in frequency-domain, image processing based wavelet transform is described to separate background image through image wavelet decomposition, then original image and background image is subtracted to remove the influence of zero frequency, and so fundamental frequency extracted easily. The proposed method reserve merit of frequency domain phase demodulation with low equipment cost and fast convenience. The proposed method is tested through three-dimensional surface sensing experiment of arc welding pool.

A new compound eyes model is designed to track the fast-moving object and detect its position with high precision in complex background. The compound eyes that consist of several eyelet channels have good nature of wide fields of view and high update rate for vision systems. Adjacent eyelet fields of view have certain degree of overlapping for detecting 3D coordinates of an object. Gradient lenses, instead of fiber bundles, are used below each eyelet lens in order to transfer eyelet image onto a re-image structure in simulation. And the eyelet image is projected onto a Charge Coupled Device (CCD) detector array through the gradient lens, avoiding expensive fiber bundles and complex assembly. Besides, simulation and analyze of the compound eyes model is performed. Neural network calibration algorithm has been adapted to build the relationship between the object points and corresponding image points for each eyelet. This calibration algorithm provides a highly accurate prediction of object data points from their corresponding image points. After getting the intrinsic and extrinsic parameters of each eyelet channel, 3D coordinates of an object can be calculated from its image points. Preliminary experimental results for Neural Network calibration are presented and evaluated, showing residual errors between actual and predicted direction angles of around 10^-3~10^-4 rad. And errors between actual and calculated coordinates of position are within 3%.

We present a new Phase Generated Carrier (PGC) demodulating system for optical seismometer and discuss its stability and consistency which is improved by modifying and compensating key parameters. A simple and easy approach to measure key parameters is presented and realized and its measure error and consistency can satisfy practical system's requirement. Several factors affecting the stability and consistency are analyzed theoretically and experimentally. The results prove that laser drive current of Direct Current (DC) bias would severely affect the stability of key parameters, and it fluctuates seriously the Signal-to-Noise-And-Distortion (SINAD) and Total-Harmonic-Distortion (THD) of demodulating result. Besides, different sensors would deteriorate the stability and consistency at a large degree which must be considered. The demodulating results have been compared between respectively modifications and unified. Other factors such as circuit gain and light attenuation also impact on system's stability and consistency, and it could be neglected at a certain extent. In this work, our system's SINAD is better than 45dB and THD is better than 50dB with the maximum fluctuation is ±1.5dB, the noise background is near -100dB/ √Hz and dynamic range has reached 130dB@100Hz.

Cascaded long period grating with film coating is sensitive to the thickness and refractive index of the film material and the surrounding refractive index, so it can be used in the applications such as gas sensing, liquid concentration sensing and bio-sensing. In this paper, the characteristic of cascaded long period grating coating with higher refractive index nanostructured film overlay is investigated theoretically by using coupled-mode theory and transfer matrix method. The responses of interference fringe peak wavelength to the thickness and refractive index of the film and the surrounding refractive index are numerical calculated. The theoretical simulation results show that the minima wavelength of the interference fringes within the long period gratings attenuation bands are sensitive to the thickness and refractive index of the film coating and the refractive index of the surrounding environment. By choosing these parameters optimally, the sensitivity of the peak wavelength shift of the interference fringes can be enhanced. The theoretical analysis can provide guidance to the application of the nanostructured film coated cascaded long period grating sensor.

An extrinsic Fabry-Perot interferometric (EFPI) optical fiber hydrogen sensor based on palladium silver (Pd-Ag) film is designed for hydrogen leakage detection. A modified cross correlation signal processing method for an optical fiber EFPI hydrogen sensor is presented. As the applying of a special correlating factor which advises the effect on the fringe visibility of the gap length and wavelength, the cross correlation method has a high accuracy which is insensitive to light source power drift or changes in attenuation in the fiber, and the segment search method is employed to reduce computation and demodulating speed is fast. The Fabry-Perot gap length resolution of better than 0.2nm is achieved in a certain concentration of hydrogen.

Airborne three-dimensional scanning laser radar is used for wholesale scanning exploration to the target realm, then three-dimensional model can be established and target features can be identified with the characteristics of echo signals. So it is used widely and have bright prospect in the modern military, scientific research, agriculture and industry. At present, most researchers are focus on higher precision, more reliability scanning system. As the scanning platform is fixed on the aircraft, the plane cannot keep horizontal for a long time, also impossibly for a long time fly in the route without deviation. Data acquisition and the subsequence calibration rely on different equipments. These equipments bring errors both in time and space. Accurate geometry correction can amend the errors created by the process of assembly. But for the errors caused by the plane during the flight, whole imaging process should be analyzed. Take the side-roll as an example; scanning direction is inclined, so that the scanning point deviates from the original place. New direction and coordinate is the aim to us. In this paper, errors caused by the side-roll, pitch, yaw and assembly are analyzed and the algorithm routine is designed.

This paper mainly introduced the procedure of designing senor nodes for detecting rescue worker's vital signs based on the wireless sensor network(WSN). The system used CC1101 chip as the radio, and C8051F as MCU which controlled the radio CC1101. In the aspect of network and communication, the design method of media layer which consisted of route layer, MAC layer, PHY layer was presented. In the end, with several such nodes, a WSN was formed, the main feature of which was a higher dynamic characteristics.

ZigBee is a new close-up, low-complexity, low-power, low data rate, low-cost wireless networking technology, mainly used for short distance wireless transmission. It is based on IEEE802.15.4 standards, thousands of tiny sensors form a network through mutual coordination to communications. This paper introduces the ZigBee wireless sensor networks in environmental monitoring applications. The hardware design, including microprocessor, data acquisition, antenna and peripheral circuits of the chips, and through software design composed ZigBee mesh network that can make data acquisition and communication. This network has low power consumption, low cost, the effective area is big, and information transfers reliable merits. And have confirmed the network's communication applicability by the Serial Com Assistant, also testified the network have very good pragmatism by the NS2 emulation the network's operation.

The focus of this study is to demonstrate and investigate the influence of photo-induced forces on the dynamics of the AFM cantilever under externally amplitude modulated laser in an ambient condition. The excitation laser at 780 nm is modulated at 20 Hz to 60 kHz and focused on the AFM cantilever surface. The cantilever vibration is monitored by HeNe probe laser. We observed highly excited vibration of the cantilever at several kHz modulation frequencies regime and at around its mechanical resonance which correspond to photo-induced forces. In addition, we noticed asymmetric peak appears at the resonance vicinity.

We theoretically analyze the influence of the forward pump lights on the flatness of gain and noise figure of bidirectional pumped fiber Raman amplifier and find a simple method to keep the flatness of gain and decrease noise figure at the same time through keeping the total integrals of forward and backward pump lights.And utilizing short wavelength lights as forward pump lights can suppress stimulated Raman scattering interaction between pump lights and get more reasonable power allocation of the pump lights.

Poly (3-hexylthiophene)-tin dioxide (P3HT/SnO₂) hybrid materials with different P3HT mass ratios were prepared by mechanical mixing. Composite films were prepared on QCM (Quartz Crystal Microbalance) by spin-coating. The films were characterized by UV-Vis spectrophotometer and SEM. The gas sensitive properties of this complex material to two series of organic vapors were investigated. The special groups in the thiophene ring were thought to be a sensory arm, which could be used to detect the target vapors. The sensitivity of the films on QCM increases with the molecule weight of alcohols and Cl-substitute methane. It is also increased with the concentration of organic vapors.