Fabrication of a 100%fill-factor silicon microlens array

正A simple method has been developed for the fabrication of a silicon microlens array with a 100%fill factor and a smooth configuration.The microlens array is fabricated by using the processes of photoresist(SU8- 2005) spin coating,thermal reflow,thermal treatment and reactive ion etching(RIE).First,a photoresist microlens array on a single-polished silicon substrate is fabricated by both thermal reflow and thermal treatment technologies. A typical microlens has a square bottom with size of 25μm,and the distance between every two adjacent microlenses is 5μm.Secondly,the photoresist microlens array is transferred to the silicon substrate by RIE to fabricate the silicon microlens array.Experimental results reveal that the silicon microlens array could be formed by adjusting the quantities of the reactive ion gases of SF_6 and O_2 to proper values.In this paper,the quantities of SF_6 and O_2 are 60 sccm and 50 sccm,respectively,the corresponding etch ratio of the photoresist and the silicon substrate is 1 to 1.44.The bottom size and height of a typical silicon microlens are 30.1μm and 3μm,respectively. The focal lengths of the microlenses ranged from 15.4 to 16.6μm.     

民航地空数据链中D8PSK信号解调算法研究

甚高频数据链模式2(VDL M2)是下一代民航地空数据链,已在国际民航领域得到应用,其物理层信号采用D8PSK调制模式。面对未来民机装备国产化的需要,地空数据链中D8PSK信号解调算法的研究势在必行。文中以国际民航组织(ICAO)发布的文件为依据,分析了D8PSK信号的特征,研究了信号的解调算法并进行了仿真实现。通过仿真模拟ICAO规定的噪声环境,对比不同解调方法的抗噪性能,明确适用于民航地空通信的D8PSK解调算法。     

T8钢淬火热处理组织的计算机模拟研究

利用有限差分法计算了T8钢二维温度场，研究了T8钢淬火热处理温度场的变化对组织的影响。根据试样任意一点的温度和冷却速度对该点的组织进行预测，实现了T8钢淬火组织的计算机模拟。     

Generalized model for the simulation of food refrigeration. Development and validation of the predictive numerical method

A generalized mathematical model was developed to simulate food refrigeration in air. The model takes into account surface water evaporation. It allows food physical properties to be considered as functions of temperature and/or composition, while providing means for including internal heat generation, composite materials (for instance, flesh and skin) and time-varying external temperature and humidity. Wetted surfaces and packaging can also be accounted for by the model, which can be used for spheres, infinite or finite cylinders, slabs. The numerical method was developed using the Crank-Nicolson scheme, and compared with exact analytical solutions as well as with experimental data on the refrigeration of various foods.     

一种改进的数据通信协议设计与实现

在主机与目标机间建立与通信端口无关的命令驱动式数据通信协议,给出数据包格式及命令功能定义。该协议采用分层和模块化设计方法,支持1553B和RS-232 2种通信端口,通过扩展底层通信管理模块可实现对CAN、SPI、SPACEWIRE等总线的支持。SPARC V8存储器加载和下载软件的运行结果验证该协议的正确性,表明其能屏蔽不同通信端口之间的差异性,实现正常的数据传输。     

Microstructure and some properties of powder-pack borided Ti–5Mo–5V–8Cr–3Al alloy with special attention to the microstructure at the interface TiB/substrate

The borided layer was prepared on the surface of the Ti–5Mo–5V–8Cr–3Al alloy by powder-pack boriding at 1000°C-10h. SEM, EPMA and TEM were used to investigate the effects of alloying elements (Al, V, Mo and Cr) on the growth of TiB whiskers in the borided Ti–5Mo–5V–8Cr–3Al alloy. Wear properties of borided Ti–5Mo–5V–8Cr–3Al alloy were investigated using dry reciprocating friction tests. SEM results show that the thickness of boride layer in Ti–5Mo–5V–8Cr–3Al alloy is thinner than that in the Cp-Ti. This is attributed to the enrichment of alloying elements especially V in TiB/substrate by TEM, which hinders the diffusion of B atoms, thus resulting in the short and thick TiB whiskers in Ti–5Mo–5V–8Cr–3Al alloy. Borided Ti–5Mo–5V–8Cr–3Al alloy has the better wear resistance than as-received alloy.     

Zeolitic imidazolate framework-8 modified cathode promotes microbial electrosynthesis from carbon dioxide

Microbial electrosynthesis (MES) is an electrochemical reduction technology through which microorganisms attached to a cathode are driven by electricity to reduce carbon dioxide (CO₂) into industrial chemicals. However, the limited contact time with biocatalysts affects the performance of MES because of low CO₂ solubility. In this study, zeolitic imidazolate framework-8 (ZIF-8) particles with different pore diameters modified cathodes were prepared. Results showed that the ZIF-8 modified electrode obtained the maximum acetate production rate (0.13 g L^?1 d^?1), which was 1.4 times that of bare CF, and the accumulated acetate concentration reached 4.04 ± 0.1 g L^?1 within 30 days. Brunauer–Emmett–Teller test and CO₂ adsorption characteristic evaluation indicated that ZIF-8 had a high specific surface area and an excellent CO₂ adsorption capacity. Scanning electron microscopy and microbial community analysis revealed that ZIF-8 modified electrodes were beneficial to biofilm formation and increased the enrichment of Acetobacterium and Arcobacter. Therefore, CO₂-adsorbing materials modified electrodes are effective in improving the performance of MES.     

Enhanced photoreactivity of MOFs by intercalating interlayer bands via simultaneous ?NCO and ?SCu modification

Herein, we propose a novel method to enhance the photoreactivity of an MOF catalyst by grafting isocyanate bonds ( NCO) and sulfhydryl-complexed copper ( SCu) onto ZIF-8 (NIF-SCu). The grafting process intercalated interlayer bands between the conduction and valence bands of ZIF-8, thereby providing a “ladder” for facile electron transition. The extreme improvement in the photoreactivity of NIF-SCu could be attributed to the enhancement in light responses in the range of 350–450 nm by  NCO groups and the widening of the visible light range of the MOF by  SCu groups. The formation of staggered energy levels in NIF-SCu could also narrow the band gap, lower the resistance, and facilitate the transfer of photogenerated carriers, thereby generating electrons with strong reduction potential in the  SCu conduction band. This study provides a new strategy for improving or even endowing the photoactivity of environmental functional materials with wide bandgaps.     

Effects of sintering temperature and Bi2O3, Y2O3 and MgO co-doping on the dielectric properties of X8R BaTiO3-based ceramics

Bi₂O₃, Y₂O₃ and MgO co-doped BaTiO₃ (BT)-based X8R ceramics were synthesized successfully for the first time. The effects of the sintering temperature and Bi₂O₃, Y₂O₃ and MgO dopants on the dielectric properties were investigated systematically. Bi₂O₃ doping can increase the Curie temperature (T_c), but reduces the overall dielectric permittivity. On the other hand, Y₂O₃ doping is beneficial to the formation of core-shell microstructure and the increase of T_c, whereas MgO can prevent excessive Y₂O₃ from diffusing into grain core, and thereby further contributes to the generation of the core–shell microstructure. The generation of the typical core-shell microstructure was confirmed and investigated in detail by using transmission electron microscopy (TEM). It is argued that the synergistic effects of Bi₂O₃, Y₂O₃ and MgO co-doping in terms of the formation of the core-shell structure and the increase of T_c, can help improve the temperature stability of the dielectric permittivity effectively. Increasing the sintering temperature leads to an increase in the grain size, which in turn leads to an increase in the overall dielectric permittivity due to the grain size effect.