An Investigation on the Coupled Thermal–Mechanical–Electrical Response of Automobile Thermoelectric Materials and Devices

Thermoelectric (TE) materials, which can directly convert heat to electrical energy, possess wide application potential for power generation from waste heat. As TE devices in vehicle exhaust power generation systems work in the long term in a service environment with coupled thermal–mechanical–electrical conditions, the reliability of their mechanical strength and conversion efficiency is an important issue for their commercial application. Based on semiconductor TE devices wih multiple p–n couples and the working environment of a vehicle exhaust power generation system, the service conditions of the TE devices are simulated by using the finite-element method. The working temperature on the hot side is set according to experimental measurements, and two cooling methods, i.e., an independent and shared water tank, are adopted on the cold side. The conversion efficiency and thermal stresses of the TE devices are calculated and discussed. Numerical results are obtained, and the mechanism of the influence on the conversion efficiency and mechanical properties of the TE materials is revealed, aiming to provide theoretical guidance for optimization of the design and commercial application of vehicle TE devices.     

Braille document recognition using Belief Propagation

There is a significant need for a system to recognize Braille documents in order to preserve them and make them available to a larger group of visually impaired people. A new system for Braille document recognition is proposed. We introduce a highly-adaptive Braille documents parameters estimation method to automatically determine the rotation angle, indentations, and spacing in both vertical and horizontal orientation. The key element in determining the rotation angle of the images is based on Radon transform. Also we introduce the method of Braille translation using Belief Propagation on the assumption that the Braille document is a Hidden Markov Model. We demonstrate the effectiveness of rotation angle correction as well as the accuracy of indentation and spacing in both orientations. We also prove that the translation algorithm is efficient and robust to errors made in the dot detection. The proposed method may be used for further applications.     

全业务时代,集团业务建设思考

讨论全业务时代集团业务发展的新要求,分析现行支撑系统的不足,分析构建以集团客户为中心,优化流程,促进协同运作,灵活配置等特点的全业务支撑体系的重要性,给出对新形势下集团业务建设的建议。     

阜阳市儿童预防接种信息系统数字化预防接种门诊试点效果评价

目的：了解依托儿童预防接种信息化系统建立的数字化接种门诊对预防接种工作流程中发挥的效果。方法：采用现况调查和自身前后对照的方法,收集和分析资料。结果：数字化接种门诊实施前后接种流程中各个阶段,差异有统计学意义（t=14.611、t =6.964、t =12.704、t =10.418、t =28.673、t =31.138,P＜0.05）,数字化后的患儿家属满意度高于数字化前,差异有统计学意义（χ2=80.954、χ2=103.156、χ2=4.536、χ2=64.737,P＜0.05）。结论：数字化预防接种门诊能够明显缩短疫苗接种效率并提高儿童家长的满意度。     

两原子－光场系统中原子和场的纯态演化

研究了两个二能级原子通过双光子跃迁与相干光场的相互作用过程中原子和场的纯态演化规律以及原子的崩溃与回复效应，讨论了原子间的偶极相互作用对它们的影响     

基于ADAMS的某型号侧置凸轮轴发动机气门系统的研究

发动机领域现在常用顶置凸轮发动机,但侧置凸轮轴发动机由于其大扭矩的优点在农业机械中仍常使用。文章通过对某型号侧置凸轮轴发动机的气门系统的CAD模型进行分析,研究了气门正时、气门升程等主要参数,并研究了气门弹簧、气门凸轮、气门摇臂和气门等主要部件的受力情况,为本气门系统的实际制造和使用提供了先期数据,便于优化改进。     

A Water Stable,Near‐Zero‐Strain O3‐Layered Titanium‐Based Anode for Long Cycle Sodium‐Ion Battery

Layered transition metal (TM) oxides of the stoichiometry Na_xMO₂ (M = TM) have shown great promise in sodium‐ion batteries (SIBs); however, they are extremely sensitive to moisture. To date, most reported titanium‐based layered anodes exhibit a P2‐type structure. In contrast, O3‐type compounds are rarely investigated and their synthesis is challenging due to their higher percentage of unstable Ti³⁺ than the P2 type. Here, a pure phase and highly crystalline O3‐type Na_0.73Li_0.36Ti_0.73O₂ with high performance is successfully proposed in SIBs. This material delivers a reversible capacity of 108 mAh g^?1 with a stable and safe potential of 0.75 V versus Na/Na⁺. In situ X‐ray diffraction reveals that this material does not undergo any phase transitions and exhibits a near‐zero volume change upon Na⁺ insertion/de‐insertion, which ensures exceptional long cycle life over 6000 cycles. Importantly, it is found that this O3‐Na_0.73Li_0.36Ti_0.73O₂ shows superior moisture stability, even when immersed into water, which are both elusive for conventional layered TM oxides in SIBs. It is believed that the small interlayer distance and high occupation of interlayer vacancy promise such unprecedented water stability.     

高度取向ZnO薄膜的介电和光波导特性研究

用溶胶凝胶法在不同的基片上制备了具有高度 ｃ 轴即（００２）取向的 Ｚｎ Ｏ 薄膜,研究了溶剂、稳定剂等对合成的先体溶液的影响。对薄膜的 Ｘ Ｒ Ｄ 分析表明随热处理温度的增加,ｃ 轴取向度增大,并且薄膜的晶粒尺寸在 ３００ ° Ｃ～５００ ° Ｃ 范围内增幅较大。用端面耦合的方法测量了制备在 Ｓｉ Ｏ２／ Ｓｉ（１１１）基片上薄膜的波导损耗,即随热处理温度的增加,波导损耗增大,主要来源于 Ｚｎ Ｏ 薄膜与 Ｓｉ Ｏ２ 的界面及晶粒的散射。制备在 Ｐｔ／ Ｓｉ Ｏ２／ Ｓｉ（１１１）基片上薄膜的相对介电常数为 ７～１３,电阻率则为 １．７×１０４ Ω·ｃｍ ～９．８×１０５ Ω·ｃｍ 。     

Salt‐Assisted Growth of P‐type Cu9S5 Nanoflakes for P‐N Heterojunction Photodetectors with High Responsivity

P‐n junctions based on two dimensional (2D) van der Waals (vdW) heterostructure are one of the most promising alternatives in next‐generation electronics and optoelectronics. By choosing different 2D transition metal dichalcogenides (TMDCs), the p‐n junctions have tailored energy band alignments and exhibit superior performance as photodetectors. The p‐n diodes working at reverse bias commonly have high detectivity due to suppressed dark current but suffer from low responsivity resulting from small quantum efficiency. Greater build‐in electric field in the depletion layer can improve the quantum efficiency by reducing recombination of charge carriers. Herein, Cu₉S₅, a novel p‐type semiconductor with direct bandgap and high optical absorption coefficient, is synthesized by salt‐assisted chemical vapor deposition (CVD) method. The high density of holes in Cu₉S₅ endows the constructed p‐n junction, Cu₉S₅/MoS₂, with strong build‐in electric field according to Anderson heterojunction model. Consequently, the Cu₉S₅/MoS₂ p‐n heterojunction has low dark current at reverse bias and high photoresponse under illumination due to the efficient charge separation. The Cu₉S₅/MoS₂ photodetector exhibits good photodetectivity of 1.6 × 10¹² Jones and photoresponsivity of 76 A W^?1 under illumination. This study demonstrates Cu₉S₅ as a promising p‐type semiconductor for high‐performance p‐n heterojunction diodes.