This PDF file contains the front matter associated with SPIE Proceedings Volume 12553, including the Title Page, Copyright information, Table of Contents, and Conference Committee information.

This study proposes a new micromechanical model, which can study the fiber composites strength by using independently fiber and matrix properties. In the new proposed composite model, which is based on two-dimensional generalized model of cells, is used to study the composites representative volume element. At the same time, a stress concentration factor is considered, in order to use the composites fiber and matrix properties. A fiber strain test which is under many different load conditions is done, which can prove the validity of the new model. Something interesting between the theoretical study and experimental data have been obtained. Compared to the proposed model without SCF, the proposed SCF model simulated results are much better. If the thermal stress is considered, the prediction results will be much better. Furthermore, the study results indicate that the matrix plasticity behavior generally make a big difference on the composites strength prediction.

Lithium-sulfur batteries are currently the most widely studied type of batteries with sulfur as the cathode. In addition to having a high energy density and theoretical specific capacity, they also offer the benefits of having a large earth storage capacity, being inexpensive, and being kind to the environment. However, the insulating characteristics, shuttle effect, and bulk effect of sulfur, as well as discharge intermediates, make it difficult to use sulfur electrodes in a broad variety of applications. This paper sorts out and summarizes the feasible solutions and current progress for optimizing sulfur electrodes and further discussed some new perspectives for developing stable and highly-electrochemically active sulfur electrodes.

The load distribution of each power plant in the power system is the process of power balance. Electricity balance is one of the important calculations in the power grid design and transmission process. Its purpose is to determine how the power and intensity of each power station in the power system can meet the needs of the entire load system. The purpose of this paper is to consult a new power system power cell balance method based on considering multiple types of flexible sources and loads. Aiming at the problem that the traditional power balance method cannot calculate the output process of a single thermal power station, using the principle of the improved successive load shedding method, through the nested structure, a new thermal power station power balance calculation method is proposed. Consulting platform for new power system power balance method. The case study shows that the power system based on the algorithm proposed in this paper is larger than the improved sequential load shedding method. This method avoids the ambiguity of the traditional power balance method in dealing with the typical daily output process and the maximum shaving capacity of each thermal power plant, and has certain advantages in solving the thermal power output process.

As a new type of welding method for special equipment, T-weld has more and more wide application scope and prospects. At present, there is still no effective and reliable method for the quality inspection of this new type of structure. In view of the testing needs of T-shaped welds, this paper proposes the use of ultrasonic phase-controlled inspection methods for common defects such as root cracks, pores, unfused side grooves on the web, and unfused side grooves on the flanges of T-shaped welded joints. Welded joints were tested, and radiographic testing methods were used for comparison. The test results show that compared with other detection methods for T-shaped welds, the ultrasonic phased array detection technology has better reliability, and can accurately identify common defects such as cracks, lack of fusion, and pores in the T-shaped welds, which is the most important part of the later T-weld. The research on ultrasonic phased array detection of type welds has laid a certain foundation.

As an important means of temporary support, anchor rods are known as "life anchors" in roadway construction, and the quality of their laying is of paramount importance due to the strict requirements for sedimentation control during the construction of underground structures. At present, the construction quality control of anchor support structures is based on destructive pull-out tests, the evaluation index of which is the anchor bearing capacity, which cannot characterise the good or bad construction work and at the same time can cause disturbance to the structure and accelerate deterioration. The elastic wave method of non-destructive testing of anchor rods is a highly promising alternative to destructive testing as an advanced means of verifying the quality of anchor construction at both the anchor rod length and anchorage compactness levels. The failure to popularise the technique is due to the complexity of the wave velocity calibration method, the low repeatability of data collection and the high reliance on experience in data analysis. In this paper, with the aid of finite element analysis and curve fitting, two aspects of improving detection accuracy are investigated in terms of optimising the wave speed calibration method and improving the data acquisition equipment, and the existing research results have been demonstrated in model tests. In this paper, two aspects of wave velocity calibration method optimisation and data acquisition equipment improvement are investigated, and with the help of finite element analysis and curve fitting, the gateway to improving detection accuracy is moved forward. After the finite element simulation analysis and solid model demonstration, the accuracy of the anchor rod non-destructive testing has been significantly improved, and the accuracy of the wave velocity theory formula has reached the application level.

PANI as an anticorrosive coating, has unique scratch and pitting corrosion resistance properties, and has a broad prospect of being a new type of metal corrosion coating in rigorous conditions. In this paper, the anticorrosive mechanism and preparation method of polyaniline anticorrosive coatings were described. The research and application of polyaniline in metal corrosion protection were introduced. The development direction of polyaniline anticorrosive coatings was explored.

Optical system is the core of flow cytometry. According to the design requirements of flow cytometry, an optical system of flow cytometry with laser as light source is designed. According to the advantages and disadvantages of the laser source and the principle of scattering light and fluorescence, the laser wavelength is determined, and the optical path structure of laser shaping and scattering light and fluorescence detection is designed. The design results of the optical system are verified by using Zemax software simulation, point diagram, energy distribution detector and other tools. The results show that the spot size of the single laser flow cytometer optical system designed in this paper is less than 10 um×150 um after laser shaping, and the spot energy distribution is greater than 80%. The scattered light can be detected by the photodiode S10993-02 (Binsong) with the effective detection surface of 1 mm×1 mm; the fluorescence of 530 nm, 570 nm, 620 nm, 675 nm can be effectively detected by 3.7 mm×13 mm H9305-02 photomultiplier detector. The optical system of flow cytometer designed in this paper meets the basic requirements of flow cytometer detection, and provides reference for the subsequent flow cytometer system design.

High-speed rail catenary fails easily due to foreign objects intrusion. Foreign objects are identified by machine vision now. However, extreme temperature changes can degrade the imaging quality of the optical system, leading to increased difficulty in foreign object identification at high altitudes. We design different types of optical systems for targets at 2 km away by Zemax and carried out thermal analysis to obtain the variation pattern of system imaging quality at different temperatures for telephoto structures and Schmidt-Cassegrain systems. The results show that Schmidt-Cassegrain structures are better adapted to wide temperature environments than telephoto structures. After correction for defocus, the Schmidt-Cassegrain structure is almost unaffected by temperature, and the telephoto structure also has good image quality within a certain temperature range. It shows that the Schmidt Cassegrain structure is more suitable for inspection along the Sichuan-Tibet Railway.

At present, femtosecond laser direct writing (FLDW) with high efficiency, has been a popular method to process all kinds of waveguide in optical functional materials. In this paper, the fabrication of Type-Ⅰ waveguides and Y-branch splitters in pure X-cut LiNO₃ (LN) crystal by FLDW has been reported. A guiding cross-section configuration has been produced, resulting from a positive refractive index area along the track induced by FLDW. An end-face coupling system has been used to explore the supported guiding modes at 632.8 nm. Experimental results reveal both TE mode and TM mode are supported in the waveguide, and the total loss of TE mode is larger. For Y-branch splitters, with the splitting angle increasing, the total loss increases rapidly.

Doppler broadening thermometry (DBT) takes advantage of the high resolution characteristic of laser absorption spectroscopy to obtain thermodynamic temperature by measuring optical frequency. It is one of the research hotspots in the field of thermodynamic temperature measurement after the Kelvin redefinition in 2018. In this paper, the direct absorption spectroscopy based on Cesium (¹³³Cs) D1 (6S_1/2→6P_1/2) line was measured, and the thermodynamic temperature of atomic gas in thermal equilibrium state was obtained by extracting Doppler width of absorption line. The experimental results showed that average relative error of thermodynamic temperature was 0.01% and the standard deviation was 0.14% after 50 rounds of testing at 303.15 K. These research results prove the feasibility of Doppler broadening temperature measurement, and provide research support for the realization and transfer of thermodynamic temperature.

The 6063 Aluminum alloy brazing joint was prepared with the Al-Si12 solder. The effect of brazing temperature on the microstructure and shear properties of the brazed seam was studied and the interface was analyzed. With the increase of welding temperature, the shear strength of 6063 aluminum alloy joints first increases and then decreases with the increase of brazing temperature. When the optimal brazing process is 605℃ for 15 min, the interface between Al-Si12 solder and aluminum alloy is good, and the shear strength is 126 MPa. The fracture form of the joint is brittle fracture. In order to ensure the bonding strength of 6063 aluminum alloy, the optimal welding temperature for brazing is 605℃.

A new type of Sm₂Zr₂O₇ ceramic material has become a candidate material for thermal barrier coating because of its low thermal conductivity, high thermal expansion coefficient and good high temperature structure stability. In this paper, the effects of different process parameters on the morphology of ceramic powders were investigated. The spray drying technology was used to prepare Sm₂Zr₂O₇ agglomerated powder. The micro morphology of Sm₂Zr₂O₇ powder after granulation was observed by SEM. The effects of inlet temperature, pump creep rate on the characteristics of agglomerated powder were analyzed. At the same time, the effects of slurry properties on the micro characteristics of powder after granulation were discussed. The optimized Sm₂Zr₂O₇ spray granulation process was determined as inlet temperature 175 ℃, pump creep rate 30% .

High elasticity salt storage class ice melting snow pavement is in high elasticity class material stress deicing and salt storage class material by reducing the freezing point deicing snow technology principle based on the effective deicing snow function, in the road paving completion of the initial deicing snow effect is more significant, but its deicing snow performance of the validation study is still relatively small. As long as the function timeliness of high elastic salt storage snow melting pavement is determined by the salt content and precipitation rate in salt storage materials. Therefore, this paper accelerates the simulation of salt precipitation through sodium chloride dissolution test, analyzes the influence of various influencing factors on the salt analysis state with conductivity as the index, and obtains the prediction equation of ice melting snow thawing timeliness, and takes Puyang city as an example to make prediction of its service life.

With the increasement of uncertainty and decrement of grid inertia caused by renewable energy generation, the ramping capacity, fast frequency response and inertia resources are crucial to ensure the safe operation of the grid. New types of anxillary services need to be gradually incorporated into the power market system to reflect value of system flexibility and reliabiltiy resources. This paper reviewed ancillary service product development for high renewable-penetrated grid among international power market design. The integration approaches of these ancillary products with the existing energy market is analyzed. Recommendations on the implementation of these products in China are made based on the generation mix and the market readiness across different provinces. With these ancillary products, the power market will be transformed to facilitate higher renewable generation and ensure safe and flexible operations.

The wear and corrosion resistance of Ni-P-SiC composite coating on AZ91D alloy were investigated in this paper. The surface morphology, microhardness, wear, and corrosion resistance of Ni-P-SiC composite coating under different deposition times were carried out by SEM, digital microhardness tester, and corrosion and wear tests. When the deposition time is 120 min, the microhardness of 641Hv is the highest, and Ni-P-SiC composite coating has better corrosion and excellent wear resistance, the values of E_corr, I_corr, and wear volume are -0.73 V, 0.78 µAꞏcm², and 1.04×10⁻³ mm³ , respectively. The properties of Ni-P-SiC composite coating are influenced by the deposition time. Ni-P-SiC composite coating deposited for 120 min has higher micro-hardness, better corrosion, and wear resistance.

The highly cis-1,4 functionalized polyconjugated dienes was prepared by high-position/stereoregular coordination polymerization of polyconjugated dienes can effectively introduce a number of heteroatom groups into synthetic rubbers, but it cannot only effectively improve the performance of synthetic rubber, but also develop new functional polyconjugated diene materials to broaden its application range. However, the rare earth metal catalysts that can promote the coordination polymerization of polar conjugated diene monomers are currently very limited. The bipyridine complex ((C₂₀H₃₀N₂)Sc(CH₂SiMe₃)₃(THF)) was simply synthesized using bipyridyl derivative ligand and equal amounts of Sc(CH₂SiMe₃)₃(THF)₂. For the bipyridyl-scandium trialkyl complex, different feeding ratios of cocatalyst borate can produce different catalytically active species. These generated catalytically active species can achieve coordination polymerization of polar 2-(2-methoxyphenyl)-1,3-butadiene.

NiTi shape memory alloys (SMAs) were utilized in electronics, medicine and aerospace, etc. One difficult point is the solid-state phase transformation of NiTi alloy during machining operations. Additive manufacturing offers a promising solution to this dilemma, which proves a new way for complex structure NiTi alloy. In this paper, we briefly introduce the research progress and status of additive manufacture (AM)-fabricated NiTi alloy at home and abroad. The phase transformation behavior was analyzed by varying AM parameters. Afterward, the previously reported superelasticity of as-built NiTi alloys in compressive and tensile stress states was summarized. The final section summarizes the main findings of tribological properties of NiTi alloys and outlines the trend for future work.

Traditional packaging materials are suffering from poor high-temperature-using, however, the SiC own ideal coefficient of thermal expansion (CTE) and thermal conductivity (TC), and at the same time, it can be used in high temperatures meeting the requirement of the advanced electronic packaging. But traditionally, SiC is made at a high temperature and with a complex producing process. Some researchers are focused on SiC with some Al additions, but we know that Al will volatilize when the samples are heated over than melt-point, so this method would also strict its applications. Other works had been taken on diamond addition to realize packaging function, but this method needed a high-temperature infiltration process too. In fact, the non-method above was economic or convenient to manufacture in nowadays industry practice. Fortunately, a new way to gain dense SiC at a very low temperature in an open environment had been gotten by our group.

Three novel compounds called 3’,3”-dodecyl-2-sulfonyl phthalein (DSP), 3’, 3”-myristyl-2-sulfonyl phthalein (MSP) and 3’,3”-dodecyl-5’,5’’-nitro-2-sulfonyl phthalein (DNSP) were synthesized to play as functional dyes in both chemical and biological areas. The as-synthesized chromotropic dyes were characterized by NMR, elemental analysis and pH value tester also the allochroic behaviors and surface activity of the new compounds were tested and performed in details mainly with the optical contact angle measurement and UV-Vis spectrophotometer. The introduction of the long chain alkyl groups into the skeleton is aiming to increase the surface activity of those dyes while that of the nitro group was focused on the regulation of the color transition point (CTP). The results indicated that the target dyes showed satisfying properties in not only the chromogenic performance but also the surface activity. Therefore, it may be an effective and durable functional dye with further potential applications in the field of pH sensors, probe and coating materials.

With the development of science and technology, more and more research has been conducted on highly conductive materials. Graphene aerogel is not only low density and high specific surface area compared with traditional conductive materials, but also has ultra-high electrical conductivity, which is a highly promising new type of strong conductive material. In this paper, graphene aerogels were prepared by chemical reduction method using graphene oxide as the reaction precursor, and the morphology and structure of the prepared graphene aerogels were characterized by scanning electron microscope images, X-ray diffraction patterns and Raman mapping.

With the improvement of the market's requirements on the color rendering of high-voltage LED light sources, accurately predicting the junction temperature of high-voltage LED, preventing led aging and extending the service life have become a topic worth studying. In this paper, the relationship between the junction temperature and the chromaticity parameters, and the relationship between the chromaticity parameters and the driving current are respectively studied for the blue excited yellow phosphor type high-voltage white LED. Finally, the functional relationship among the junction temperature, the chromaticity parameters and the driving current is established. To further accurately predict the junction temperature of the high-voltage LED. Subtracting the color fidelity R_f and color gamut R_g of the initial state from the color fidelity and color gamut at the measurement temperature to obtain the relative chromaticity parameters ∆R_f, ∆R_g can eliminate the self heating effect of the current; subtracting the initial temperature T_j from the measured temperature to obtain the relative junction temperature ∆T_j can eliminate the temperature deviations introduced by the high temperature chamber. The functional relationship among the relative junction temperature ∆T_j and the relative chromaticity parameters ∆R_f, ∆R_g fitting curve are obtained. For 12V and 6V high-voltage LEDs with the same power, the linearities of the fitting functions of ∆T_j-∆R_f and ∆T_j− ∆R_g are close to one. Compared with the results measured by T3ster, the maximum errors of junction temperature prediction based on color fidelity and color gamut are 3.33% and 4.24% respectively, which are within the acceptable range. It shows that these methods are entirely feasible and has particular practical value.

The nickel-based BaF₂-CaF₂ composite coating was fused onto the H13 substrate using laser melting technology. The morphology, microstructure and phase composition of the molten layers were observed and determined using scanning electron microscopy (SEM), X-ray diffraction (XRD), energy dispersive spectrometer (EDS) and metallographic microscopy. The friction and wear properties of the coatings were tested and analyzed using a friction and wear tester, and the friction and wear behavior and lubrication mechanisms of the coatings at high temperatures were investigated. The results showed that the microhardness of the clad layer decreased with the increase of BaF₂-CaF₂ content, and the average microhardness of the clad layer was 547.61 HV. The clad layer with 92% Ni60+8% BaF₂-CaF₂ composite powder had the best quality and showed good friction reduction and anti-wear effect in the test high temperature range, and the friction coefficients were all below 0.25, and the wear rate was 67.9% less than that of the substrate. The wear rate was reduced by 67.9% compared with that of the matrix. It benefits from the enhancement of the Ni-based powder and the selflubricating properties exhibited by BaF₂-CaF₂ at high temperatures as well as the synergistic lubricating effect of the large amount of oxides generated by friction.

The self-injection locking based on the microcavity can be generated when the microcavity is directly pumped by the laser diode, and the linewidth can be narrowed. In this work, we used a DFB laser to pump a silicon nitride (Si₃N₄) micro ring resonator (MRR) with a 5e5 quality (Q) factor. Tapered fiber was used for the chip waveguide end face coupling. The transmission spectrum and wavelength locking region were obtained by scanning the drive current of laser diode. 0.09 nm width locking region was achieved at 1552.6 nm. Finally, the linewidth of the output laser was measured using path modulation non-zero frequency self-heterodyne interference method. Linewidth narrowing was found by comparing free running state and self-injection locking state of the laser diode. The experiment results show five times linewidth narrowing. The self-injection locking laser based on Si₃N₄ MRR is realized through fiber coupling, which is simple and compact in structure and significantly reduces the difficulty of optical alignment. At the same time, it can obtain extremely narrow linewidth, which has broad application prospects in precision metrology, optical fiber sensing, optical communication.

Nondestructive testing plays an important role in modern cities. Laser-generated surface acoustic waves (SAWs) are widely used in the nondestructive testing of structures due to their advantages, such as being non-contact and having a wide frequency bandwidth, long distance propagation, little attenuation, and so on. Q345 steel is currently used in many areas, especially in large structures. In order to utilize laser-generated SAWs more reasonably, this paper discusses the effects of laser parameters on the excitation of SAWs in Q345 steel with the numerical method. The three parameters of the pulse energy, rise time, and pulse width are discussed separately. The results show that the amplitude of displacement is directly proportional to the pulse energy and inversely proportional to the rise time and pulse width. These proposed results can provide a guideline for the choice of the excitation parameters in the laser-generated SAWs nondestructive evaluation on Q345 steel.

Transparent neodymium-doped yttrium aluminum garnet (Nd:Y₃Al₅O₁₂) is an ideal material for high power solid state lasers. In this paper, Nd:YAG transparent ceramics were prepared by solid state reaction and vacuum sintering. The microstructure and absorption spectra of Nd:YAG transparent ceramics were analyzed by scanning electron microscope (SEM) and ultraviolet-visible spectrophotometer (UV). The output power, slope efficiency and light-to-optical conversion efficiency of Nd:YAG transparent ceramics were investigated through the LD pumping experimental platform, and the effect of TEOS (Si(OC₂H₅)₄) addition on the laser performance of Nd:YAG transparent ceramics was further discussed. The research results show that the laser output power and laser emission intensity of ceramics reach the maximum when the addition amount of TEOS is 0.5wt% under the same pump power.

The Laser Doppler Vibrometry (LDV) system can measure parameters such as amplitude, velocity and acceleration of micro-vibrating objects. However, in the actual measurement process, in addition to the probe beam and the reference beam, as the surface roughness of the measured object increases and the diffuse reflectance decreases, the echo energy of the laser will decrease rapidly. This phenomenon can be extended to heterodyne detection systems. Due to the limitation of optical devices, the third beam (ie stray beam) caused by parasitic reflection is unavoidable. At the same time, the third beam has a certain intensity and phase distribution, which seriously affects signal demodulation of micro-vibrating objects. This paper analyzes the effects of multi-beam interference competition in heterodyne demodulation systems. Mathematical analysis shows that the interference competition depends on the signal amplitude, the interferometric light intensity ratio and the relative phase difference. Through mathematical derivation and simulation verification, the following conclusions can be drawn: when the relative phase difference is π rad, when the ratio of light intensity between the probe light and the stray light is controlled to tend to one, the simple harmonic motion with an amplitude of 1 nm is demodulated, and the amplitude can be observed to be nearly 200 times of the enhancement effect. For micro vibration with different amplitudes, the simulation shows that when the amplitude coefficient is π, the demodulation amplitude does not have amplification effect, and the amplitude coefficient is π can be used as the limit of demodulation amplitude amplification. This method has great application value in the high-sensitivity measurement direction of micro-vibrating objects.

Vanadium dioxide film can be used to anti-laser interference infrared detector. If the laser energy is strong enough, the film may also be damaged under laser irradiation. VO₂ thin films were prepared on sapphire substrates by molecular beam epitaxy. The laser damage threshold test of VO₂ film was designed. VO₂ film was irradiated with 1064 nm laser, and the damage characteristics of the film were observed by metallographic microscope. The damage threshold of the film was determined according to the damage morphology. The experimental equipment of laser pretreatment to enhance the film damage threshold was set up, and the laser energy of 20%-90% of the film damage threshold was used to pretreat the film. It is found that there is an optimal pretreatment energy for raising the damage threshold of vanadium dioxide films by laser pretreatment, and the optimal pretreatment energy is 60% of the damage threshold energy. The damage threshold of vanadium dioxide films pretreated with this energy was increased by about 31%.

To reduce the loss caused by uneven settlement of substation foundation buildings, it is urgent to carry out long-term and real-time monitoring of the engineering structure. The FBG (fiber Bragg grating) flexible sensor was fabricated by using the POM (polyoxymethylene) material with waterproof and moisture-proof properties as the flexible substrate, and encapsulating the sensing points in the substrate by means of grooves. Temperature sensing experiments have shown that flexible sensors have good temperature self-compensation properties. In the displacement sensing experiment, the mean absolute errors of Type 1, 2 and 3 were 2.67 mm, 2.77 mm and 6.76 mm, respectively, after the curvature information obtained by the sensing point was corrected by B-spline interpolation. Compared with before correction, the mean absolute errors were reduced by 38.28 mm, 9.94 mm and 28.54 mm, respectively. The mean absolute displacement error percentages of Type 1, 2, and 3 after correction by B-spline interpolation were 1.87%, 5.28%, and 6.98%, respectively, which were 26.83%, 18.94% and 29.49% lower than those before correction. The above has shown that the interpolation algorithm effectively improves the sensing accuracy of the flexible sensor for displacement. The FBG flexible sensor designed in this paper can realize real-time monitoring of substation settlement and provide early warning, which has important application and promotion value.

Stacking sequence of laminated composite plates are optimized by iteratively calculating the FE model using Isight and Abaqus. Three optimization algorithms, quadratic sequence programming method (SQP), Hooke-Jeeves method (HJ), and genetic algorithm (GA), are adopted and their characteristics are compared. Results show GA can converge to the global optimal value with low efficiency, and SQP and HJ can reach the local optimal values efficiently.

In order to solve the problem of the influence of time-varying green certificate on the operation benefit of virtual power plant, promote the full interaction between virtual power plant and large power grid, and improve the new energy consumption capacity, a virtual power plant economic dispatching model based on time-varying green certificate was proposed. The biggest difference between the time-variant green certificate and the traditional green certificate is that the green certificate of new energy generation is related to the transaction price of electricity in this period, so that the green certificate can reflect the cost paid by the market subject to consume new energy in this period. The influence of time-variant green card on the operation mode of virtual power plant is analyzed. By introducing the green card revenue function based on time-varying green card into the optimization model, a virtual power plant economic scheduling model with time-varying green card was constructed. The simulation results show that the virtual power plant will use adjustable resources with relatively high cost to promote the consumption of new energy and obtain higher green license income. The results show that the time-varying green card is helpful to improve the market participants' new energy consumption price tolerance, thus promoting the new energy consumption capacity.

The accurate prediction of wind power is related to the accuracy of power generation plan and overall scheduling, and wind power is a clean energy with randomness, intermittence and volatility. Therefore, we propose a novel short-term wind power prediction method based on hybrid deep neural network. This method does not require meteorological data and only uses a two-stream framework. The spatial features were extracted by using one-dimensional convolutional network, the long short-term memory network (LSTM) was used to extract temporal features, and then fuses the two parts of features for prediction. Through the analysis of three years' data of a wind farm in east China, we prove the validity and practicability of the prediction model, which provides strong support for the reliability analysis of power prediction.

With the development of smart meters, a large number of high-dimensional load data become available, which also brings great challenges to load pattern clustering (LPC). Although current studies have been devoted to extracting features from high-dimensional load data to achieve dimensionality reduction, they focus on the manually extracted features, which may not be able to effectively model the nonlinearity of load data. In this paper, a fused load pattern recognition method based on deep representation feature extraction is proposed to solve this problem. Specifically, two unsupervised deep representation feature extraction models are conducted to extract the characteristics of customers' electricity consumption behaviour from different views, which are convolutional neural network based autoencoder (CNN-AE) and long short-term memory based autoencoder (LSTM-AE) respectively. Then, the fusion feature selection (FFS) method is proposed to construct a set of effective feature subspaces. Finally, the ensemble clustering based on co-association (CA) is carried out to obtain the clustering results. Experimental results show that the proposed method can effectively improve the clustering performance of load profiling.

High luminous efficiency and good colour rendering are the goals of white light spectral optimisation, improving the quality of light and creating a comfortable light environment is the direction of research. The goal of the work is to establish a multi-channel spectral optimization technique for light emitting diodes (LEDs) based on visual advantages. Using actual LED parameters as input, the traditional colour rendering index (Ra) and a stricter colour tolerance was used as constraints in the visual evaluation. Specifically, Ra>90, luminous efficacy of radiation (LER)>300, color tolerance less than five SDCM. Those that satisfy all three conditions at the same time are used as the solution set for intermediate vision evaluation. The results of the study show that at least four channels are used to satisfy the constraints. Additionally, we examined the relationship between S/P values and color temperature (CCT) when using intermediate vision, and the findings indicate that LED light sources with higher color temperatures are better suited for these situations.

Graphene is the most studied material in the world in recent years, from two dimensions to three dimensions, through Bernal stack to multilayer, and finally into graphite, we can see obvious dimensional changes. Therefore, the interaction between layers is very important, and one of them, twisted graphene, which is different from natural ordered stack, has also appeared. If the rotation angle is regarded as a new degree of freedom, angle related properties can be introduced into graphene, and a series of new physical phenomena have become a new research interest. This article shows a transfer glass slide for picking up two-dimensional materials, which can effectively pick up hBN, graphene, etc. The low-angle twisted (1+2) trilayer graphene and hexagonal boron-nitride heterojunction was made by tear-rotate-pick, and their stacking rules were observed by Raman spectroscopy. We found that after covering a certain thickness of hBN, the Raman characteristic peak intensity of the trilayer graphene has a certain attenuation, and has a great impact on the G peak, while the G peak and 2D peak positions have a shift of 2 cm^-1 and 5 cm^-1 respectively. The Raman spectrum of the low-angle twisted trilayer graphene prepared by us also shows a different characteristic peak pattern from that of the common ABA and ABC stacked trilayer graphene. Among them, the G peak of the 0.1° sample becomes flat, and the 2D peak appears an obvious inflection point. While the 0.5° sample is similar to the ABA stacked trilayer graphene, but the 2D peak is more gentle.

In recent years, micro-columnar cesium iodide (CsI) scintillation films remain a highly desirable sensor for digital X-ray imaging due to its superior spatial resolution, bright emission, high absorption efficiency and ready availability. The micro-columnar structure of the CsI scintillation films can reduce the lateral diffusion of scintillation light and greatly constrain the transmission behavior of fluorescence. However, CsI scintillation films exposed to humid air are easily deliquescent and damaged. In this paper, the preparation methods and anti-deliquescence measures of CsI scintillation films in recent years are mainly summarized and their respective characteristics and limitations are also comprehensively compared and analyzed, which can provide a reference for the preparation and application of high-performance CsI columnar microcrystalline scintillation films in the future.

Vanadium dioxide (VO₂) films play an increasingly important role in laser protection. The mid-infrared switching characteristics of VO₂ films are tested. The phase transition response time is measured and is at the nanosecond level. Measured at five wavelengths of 3.5 μm, 3.7 μm, 3.9 μm, 4.1 μm, 4.5 μm and 4.7 μm, the maximum of the power attenuation multiple before and after the phase change of the thin film was 13.29, and the minimum was 7.78. The switching characteristics of VO₂ films are obvious. In addition, the phase transition thresholds and damage thresholds of lasers with wavelengths of 3.7 μm, 3.9 μm and 4.1 μm on VO₂ films were measured. It was found that with the increase of the wavelength, the thin film phase transition threshold decreased and the damage threshold increased. The film has a good protective effect on mid-infrared lasers.

Vision sensor is one of the sensors that can obtain the most abundant environmental information by a single sensor at present, but a single sensor is still limited by the influence of complex environment, which makes the obtained environmental information and actual environmental information quite different. Therefore, the fusion of infrared vision sensor and visible light vision sensor is used to express the environment in multiple dimensions after fusion, which can effectively enrich the image information and supplement the required environmental information. In this paper, two-dimensional discrete wavelet is used to process the visible image and infrared image separately. The obtained fusion image retains the information of the original image and solves the problem of artifacts and ghosting of the fusion image.

If Toeplitz matrix is used for compression-aware ghost imaging, the imaging quality will be very low. In order to solve the problem, a new experimental scheme for ghost imaging is proposed in this paper. The scheme first extracts the Toeplitz matrix elements randomly and sparsely using a revolving matrix, and then modulates the illumination light field. The sampling is performed by using the Toeplitz matrix as a fixed matrix and another measurement matrix as a revolving matrix. The revolving matrix rotates around its center at a constant angular velocity. The fixed Toeplitz matrix is superimposed with the revolving matrix to form the optical field modulation matrix. The results of simulation experiments show that light field modulation scheme of the rotational random extraction of Toeplitz matrix can modulate the light field with more randomness. The use of this scheme in ghost imaging experiments results in high quality images with low distortion.

The color shift problem caused by OLED aging has always been a hot issue in the field of OLED display. The difference of pixel attenuation rate of different colors will seriously affect the display effect of the device. In this paper, image signal generators and lifetime testers were used to test the brightness and color coordinate changes of OLED display under different initial brightness during the aging process. In addition, the causes of white dot color shift and the trajectory of color shift were explored. The research results show that the reduction of blue light ratio caused by the rapid decay of blue pixel efficiency is the cause of the color shift of the white picture, and the color shift trajectory from the white light area to the yellow light area causes the white picture to be yellowish. In order to correct the color shift of the white screen, the thickness of the HIL (hole injection layer) is optimized. The study found that when the thickness of the hole injection layer is 1070 Å, the chrominance efficiency of blue pixels can be kept in the peak area, and the improvement effect is significant, the slope of the color shift locus is reduced to 1.26, the color shift value is reduced from 0.0051 to 0.0017, and the JNCD is less than one.

As a new type of detection technology, photodetector has played an extensive role in military and civilian fields, especially having multi-band detection capabilities. Therefore we have demonstrated a fast-speed ultraviolet-visible photodetector which based on the amorphous-Ga₂O₃/p-Si heterojunction with the comb-shaped Au electrode. At 10 V bias, the a-Ga₂O₃/p-Si photodetector shows two response peaks which are at 292 nm and 560 nm, with the responsivity for the UV and visible reaching as 6.39 A/W and 7.72 A/W, respectively, which shows that this detector has a good dual-band detection capability. And the fast response speed can also be clearly observed with 90%-10% decay times of less 80 ms, which is satisfiable to the needs of modern fast detection. Our findings provide new ideas for fabricating high-performance photodetectors.

The refractive indices of liquids were measured in this study by designing an experiment using the “double dark ring” effect produced by the liquid membrane between two glass plates. The refractive indices of Coca-Cola, 25.5% sodium chloride (NaCl) solution, and saturated sucrose solution were separately measured with the formula method and the graphical method. The results showed that the refractive indices of liquids measured by the formula method were more accurate. The measured values were 1.3515, 1.3999, and 1.5230, respectively, and the relative errors with those measured by the Abbe refractometer were 0.208%, 0.391%, and 0.658%, respectively. Due to its many advantages, including the small amount of the liquid to be measured required, low experimental cost, easy and repeatable operation, and high accuracy, this method can serve as an important approach to study the liquid refractive index in the future.

Incoherent broadband cavity enhanced absorption spectroscopy (IBBCEAS) based on light emitting diode (LED) has been used for quantitative measurement of NO₃ radical due to its high sensitivity. However, the fluctuation in LED temperature changes the center wavelength and intensity of LED radiation spectrum, resulting in reduction of performance of IBBCEAS instrument. In this paper, an IBBCEAS-based NO₃ measurement setup using red LED as light source is developed for investigating the influence of LED temperature shift on measurement of NO₃ radical. The reference IBBCEAS spectra recorded at from 0 ℃ to 40 ℃ of LED temperature with an interval of 5 ℃ are used to construct absorption spectra of 100 pptv NO₃. Another recorded spectrum at 20 ℃ is used as the reference IBBCEAS spectrum, combining with the constructed IBBCEAS absorption spectra, subsequently the absorption coefficients under different LED temperature shifts are obtained, and then we fit the NO₃ absorption cross section to the absorption coefficients for retrieving the NO₃ concentration. The results show that the standard deviation of fitting residual will increase by ~1.65×10⁻¹⁰ cm⁻¹ if LED temperature is shifted by 1 ℃, which indicates that the limit of detection for NO₃ is increased by ~1 pptv.

To investigate the relationship between refresh frequency and human visual comfort in lighting, an experiment was designed based on subjective emotion and physiological parameters. The impact of three monochromatic light (red 623 nm, green 537 nm, and blue 445 nm) and two different white lighting (3000 K, 6500 K) were also examined. According to experimental results, each lighting has a frequency that is most comfortable in the situation of non-static light. Although both dynamic and static light have an effect on human physiological parameters, it is clear that dynamic light causes more significant changes. A physiological analysis found that lower light flicker frequencies and red/blue flicker had the greatest effect on visual acuity, and that changes were greater in myopic than orthoptic eyes. The findings demonstrate that the refresh frequency of lighting has impacts on physiological parameters as well as subjective emotions.

Optical performance monitoring technology (OPM) is a technology to monitor the physical state and transmission quality of optical network. In this paper, a scheme based on asynchronous delay tap histogram (ADTP) is proposed. On this basis, Convolutional Neural Network (CNN) and Support Vector Machine (SVM) are used to monitor optical performance, which completed modulation format recognition (MFI) and network performance parameter estimation under different damage. In this paper, an optical signal simulation system for 112 Gbps of DP-QPSK, DP-16PSK and DP-16QAM is set up. The optical signal-to-noise ratio (OSNR) and chromatic dispersion (CD) are mainly monitored. Asynchronous delay tap histogram is formed by asynchronous delay sampling. After extracting the characteristic parameters by CNN, the modulation format recognition, parameter OSNR and CD estimation are made. The simulation results show that CNN performs well in modulation format recognition, OSNR and CD estimation, with 100% modulation format recognition accuracy, 95% OSNR estimation accuracy, 95% CD estimation accuracy, 3.44% higher than asynchronous amplitude histogram (AAH)+SVM OPM scheme, and 40.79% higher than ADTP+CNN OPM scheme.

Enterprise credit assessment is important for financial institutes. To enrich the evidence for credit analysis, this paper proposes to use the electricity consumption data to obtain an absolute credit score. Instead of creating the direct mapping between the electricity consumption data and credit score, we train a deep model to predict which enterprise has higher credit score given two enterprises. To learn deep model, we utilize the ranknet model to learn the ranking information from the electricity consumption data. To improve the training efficiency and robustness, we propose a ranking-based representative enterprise sample selection method to optimize the training dataset. During the inference, the learned ranknet model is performed to generate the absolute credit score by a ranking-based score mapping method. The experimental results demonstrate that the method in this paper can achieve accurate enterprise credit evaluation.

In this paper, a method for the rapid design and fabrication of multifocal microlens arrays based on photomultiplier digital micromirror devices is presented. In the method of adopting digital micro lens device instead of conventional hot reflux method, to avoid the hot reflux method the characteristics of the complex process, high costs, the use of special digital gray mask instead of the binary mask, point by point correction more focusing microlens array of sphere, to avoid the binary mask multi-exposure cause accumulated error serious etc. The results show that the actual profile agrees well with the design profile by using grayscale mask, and this method provides a convenient way to prepare high quality multi-focus microlens array.