Search

A novel systematic technological process for ZnO-thin-film transistors (TFTs) fabrication was developed which turned out to achieve near-zero threshold voltage devices with good performance and stability. A deuterium implantation method was realised as well to fabricate depletion n-type ZnO TFTs. The inverters based on enhancement/depletion ZnO TFTs reached nearly full swing (0.01-5 V at 5 V VDD) and pretty large noise margin (VNML = 1.01 and VNMH = 3.61 V). Moreover, a transparent radio-frequency identification (RFID) tag chip based on ZnO TFTs was developed. This tag with an anti-collision algorithm for ISO-14443 type-A was first realised under 5 μm ZnO-TFT technology. The proposed RFID tag exhibits ultra-low-power dissipation of

To increase the power generation efficiency of tower solar thermal power generation system, an annular compound parabolic concentrator is designed and installed at the heat receiver which is on the top of this system. The structure of the annular compound parabolic concentrator can well adapt to the light field distribution of the annular heliostat field in the system, and the solar energy reflected by heliostats can be efficiently concentrated by annular compound parabolic concentrator to the surface of the heat receiver. Using the annular compound parabolic concentrator can reduce the surface area of the heat receiver, increase the concentration ratio of the system, then raise the system’s power generation efficiency. Simulation and experimental results show that, the annular compound parabolic concentrator increases the system’s concentration ratio by about 94.4% and extend the system’s daily working hours, especially in cloudy days, so as to improve the generating efficiency by about 3 percentage points.

Spray-freeze drying (SFD) is a novel and advanced drying technology in the production of high-value foods and pharmaceuticals. However, long drying time is still a disadvantage for the SFD applicat...

Spray freeze-drying is a process to directly produce high quality powders with short drying time. The difference of microstructures has a great influence on the physical properties of powders. However, during the spray freeze-drying process, the freezing degree of droplets in the drying chamber will change the product structure and affect the powder quality. In this study, the surface structure and morphology of dry powders were observed using scanning electron microscopy. The formation mechanism of droplet morphology during spray freeze-drying was analyzed. The results show that the rapid freezing process can produce finer microstructures.

A series of MCM-41 molecular sieves with different molar ratio of template to silicon were synthesized through hydrothermal synthesis method by using cetyltrimethylammonium bromide (CTAB) as the template, diatomite as the silicon source. By using impregnation method, the Mn-Ce/MCM-41 SCR molecular sieve-based catalysts were prepared. The results observed that when the molar ratio of template to silicon was 0.2:1, the MCM-41 as catalyst carrier has the highest surface area and largest pore volume, it also presented typically ordered hexagonal arrays of uniform channels. The denitration catalytic material based on this carrier has a high number of Lewis acidic sites, and the denitration efficiency can reach more than 93%.

This work studies the impact protection properties of both martensite NiTi wires and superelastic NiTi wires, with 0.5 mm diameter, at different initial impact energies using a new-designed impact test plant. In particular, impact experiments under a specific temperature range of A s - A f , were performed for the martensite NiTi wires. The test results show that both the martensite NiTi wires and superelastic NiTi wires have excellent impact protection properties and can dissipate a significant amount impact energy compared to other more metal materials such as Cu, Fe, and Al. Otherwise, the martensite NiTi wires can dissipate more impact energy in a shorter period of time than superelastic NiTi wires while generating a smaller impact force, F max , due to their larger plastic deformation energy. Moreover, the dissipated energy, W d , of martensite wires increases from 23.8 MJ/m3 to 53.6 MJ/m3, and the impact force, F max , increases from 42.96 N to 95.9 N, while the temperature rises from 35 °C to 65 °C. That means the impact protection properties of martensite NiTi wires are temperature dependent in a specific temperature range A s - A f . Those results in this study also reveal that the impact protection properties of both martensite NiTi wires and superelastic NiTi wires represent the basis for new shape memory damping element applications, particularly in automotive safety systems.

A series of catalytic coatings consisting of MnOx-CeO2 and TiO2 support were prepared by atmospheric plasma spraying, which was aimed at the application of selective catalytic reduction (SCR) of NOx. The effect of the load of active component on the coating was firstly studied. The results showed that all the coating presented the highest catalytic activity at approximately 350 &deg, C and the coating with the composition of 20MnOx/5CeO2/TiO2 (wt%) achieved the most powerful performance. The coating was then prepared on a wire-mesh structure substrate, which can be easily assembled as a gas filter. The results showed that the specific surface area was greatly increased resulting in the significant improvement of the catalytic activity of the coating. This strategy offered a promising possibility of removing NOx and particulate fliting simultaneously in industrial applications.

With sulfonated electrospun polystyrene fiber as a template, uniform polyaniline(PANI) nanotubes were fabricated via polymerization of aniline followed by template removal. Au nanoparticles(Aunano) were decorated on the PANI nanotube successfully via auto-reduction of HAuCl4 on the PANI nanotube. The morphology of the nanotubes was characterized by means of scanning electron microscopy(SEM) and transmittance electron microscopy(TEM). By varying precursor concentration and incubation time, Aunano-PANI with different size of Aunano was obtained conveniently. Glassy carbon electrode modified with the Aunano decorated PANI nanotubes (Aunano-PANI/GCE) was prepared and used seccessfully for the catalytic oxidation of ascorbic acid(AA). The results of differential pulse voltammetry indicate that there is a good linear relationship between the peak currents and the concentrations of AA in the range of 5―3000 μmol/L, with the limit of detection of 1 μmol/L(S/N>3). There is no mutual interference between AA and dopamine. The electrode has been successfully applied in the detection of AA in vitamin C tablet sample.

Triangular-pyramidal ω-Bi2O3 is successfully synthesized via a one-step wet-chemical method. XRD, SEM, and UV-vis have been employed to characterize the as-prepared samples. Structural characterization by XRD confirms the formation of triclinic ω-Bi2O3 with high purity. The well-defined flower-like Bi2O3 structures consisted of many triangular-pyramids are formed. Preparative parameters, such as concentration of PEG 6000, have great effects on the morphology and the particle size. The obvious absorption edge for ω-Bi2O3 powder is located at about 493 nm, which corresponds to the optical band gap energy of 2.73 eV.

Modifying a semiconductor photoanode with an oxygen evolution cocatalyst is an effective method for improving the photoelectrochemical (PEC) water decomposition efficiency. Here, PEC efficiency of BiVO4 electrode is enhanced by constructing a NiCo-LDH/BiVO4 heterojunction. Under the synergistic effect of NiCo-LDH and BiVO4, the photocurrent, incident photon-to-current conversion efficiency and hydrogen production of NiCo-LDH/BiVO4 electrode have been significantly improved, which are mainly attributed to the enhancement of internal light absorption, photogenerated carriers transfer and separation.

The energy dissipation properties of martensite NiTi SMA wires under two different loads, including a quasi-static tensile load and an impact load, are studied through our newly designed testing plants. Meanwhile, by changing the temperature of the SMA wires, the controllability of energy dissipation of the SMA wires is discussed in detail. The results indicate that martensite NiTi SMA wires show excellent energy dissipation capabilities under the loads. It is also found that the energy dissipation properties of the SMA wires can be improved by changing their temperature. The energy dissipation properties of martensite NiTi SMA wires demonstrate that NiTi SMAs have the possibility to be applied in smart automotive safety systems.

[EN] In this paper, the effect of spray droplets on the coating of cold spherical particles was studied.The microcapsule granulator produces micron-sized droplets to coat the spherical particles in cold storage, and the high-definition camera and precision balance are used to photograph and weigh the particles before and after the spraying. The droplets are obtained by using the image and data processing technology coating area and coating quality, the droplet coating effect was evaluated by a number of dimensionless parameters such as coating ratio and mass ratio.By orthogonal design experiment and uncertainty analysis, the effects of droplet size and flow rate, spherical particle temperature and diameter on coating effect were studied, and the effect of droplet group coating on low temperature spherical particles was obtained., The authors acknowledge Projects supported by the National Natural Science Foundation of China (Grant No. 31571906 & No.21506163).

The optical losses of asymmetric and symmetric waveguide structures were calculated theoretically for high power 980 nm diode lasers, by means of the continuity equation under strong injection and the Helmholtz equation of complex refractive index model. The epitaxial materials of the both waveguide structures were prepared by the metallorganic chemical vapor deposition growth technique, and corresponding laser devices were fabricated. The electro-optical performances of both devices were measured and analyzed by comparison. The theoretical calculations and experimental results indicates that, the asymmetric waveguide structure material does not reduce the optical loss, but decreases the series resistance of the diode, therefore, it reduces the joule heating, and enhances the conversion ef

为了实现激光二极管阵列(LDA)的高亮度光纤耦合输出,设计了一套简单有效的光束整形系统.首先采用快慢轴准直透镜压缩LDA的发散角,然后采用双平行平面反射镜光束整形装置,将压缩后的LDA慢轴方向的光束分为4束(也可以根据需要分为任意多束),并将4束子光束在快轴方向重新排列,最后通过聚焦系统,将整形后的光束耦合进入芯径600 μm,数值孔径0.37的光纤.实验测得双平行平面反射镜整形装置的效率为98.87%,系统的整体效率为77.2%.该整形系统设计简单,效牢高,具有很高的应用价值.

Due to the zero dispersion point at 1.3-mu m in optical fibres, 1.3-mu m InGaAsP/InP laser diodes have become main light sources in fibre communication systems recently. In fluences of quantum noises on direct-modulated properties of single-mode 1.3-mu m InGaAsP/InP laser diodes are investigated in this article. Considering the carrier and photon noises and the cross-correlation between the two noises, the power spectrum of the photon density and the signal-to-noise ratio (SNR) of the direct-modulated single-mode laser system are calculated using the linear approximation method. We find that the stochastic resonance (SR) always appears in the dependence of the SNR on the bias current density, and is strongly affected by the cross-correlation coeffcient between the carrier and photon noises, the frequency of modulation signal, and the photon lifetime in the laser cavity. Hence, it is promising to use the SR mechanism to enhance the SNR of direct-modulated InGaAsP/InP laser diodes and improve the quality of optical fibre communication systems.

In order to improve the output power and increase the lifetime of laser diodes, expansion-matched submounts were investigated by finite element analysis. The submount was designed as sandwiched structure. By varying the vertical structure and material of the middle layer, the thermal expansion behavior on the mounting surface was simulated to obtain the expansion-matched design. In addition, the thermal performance of laser diodes packaged by different submounts was compared. The numerical results showed that, changing the thickness ratio of surface copper to middle layer will lead the stress and junction temperature to the opposite direction. Thus compromise needs to be made in the design of the vertical structure. In addition, the silicon carbide (SiC) is the most promising material candidate for the middle layer among the materials discussed in this paper. The simulated results were aimed at providing guidance for the optimal design of sandwich-structure submounts.

We report a new technique, called SAP, for side pumping of double-clad, rare-earth-doped fiber lasers using fiber-coupled pump sources. The highest coupling efficiency can even exceed 92% in theory with this structure.

Design of the typical laser diode side-pumped Nd:YAG rod system has been discussed using the conventional ray tracing method in this paper. Firstly introduce two basic matrices, refractional and translational matrix, described the transmission of nonparaxial light ray in the medium without concerning the absorption of light. And then, using those matrices, analyze the distribution of pump light in the crystal respectively under the condition of directly pumped system and indirectly pumped system with a cylindrical quartz rod as focusing lens. From the result of simulation, we compare the advantage and disadvantage of the two pumped method, and mainly consider how to select the diameter of the focus lens and cooling tube, indicate the effect of deionized water and cooling tube have on the pump light distribution in the active material. At last, make some conclusions about the side-pumped Nd:YAG laser system.