基于原子-分子共存理论的全浓度Ti-Al二元熔体热力学性质计算（英文）

基于原子-分子共存理论建立计算温度为1973~2273 K及全浓度范围Ti-Al二元熔体质量作用浓度Ni的热力学模型。利用不同温度(1973、2073、2173和2273 K)下的模型计算结果,得到在无限稀溶液(0x_(Ti)0.01)中铝、钛活度因子的对数与温度的关系式。根据该表达式,进一步得到组元i溶解于Ti-Al二元熔体形成浓度为1%(质量分数)溶液为标准态的溶解Gibbs自由能。与此同时,对Ti-Al二元熔体的过剩Gibbs自由能、过剩熵、过剩焓也进行了计算。     

V型发动机两次判定可调气门法

指出在Ｖ型发动机两次判定可调气门的工作中易出现的错误，阐述采用简化工作循环图判定可调气门的方法，通过两个黄型例子，以加深对其理解和掌握。     

Development of the zinc-air power battery on electric bicycles in China

Electric bikes powered by lead-acid batteries have developed very fast for several years in China. Because the inconvenience caused by the service performance and the inconsistency to the environmental protection policy of the lead-acid battery, the zinc-air power battery was proposed to solve the problem in this paper. The advantage and the feasibility of developing zinc-air power batteries in China have been illustrated in the paper. And, it is represented that development of electric bikes powered by the zinc-air power battery also can accelerate this kind of battery’s development in other electric vehicles, which is favorable to economic development and environmental protection.     

Fast valve power loss evaluation methodfor modular multi-level converter operatingat high-frequency

There is no common accepted way for calculating the valve power loss of modular multilevel converter (MMC). Valve power loss estimation based on analytical calculation is inaccurate to address the switching power loss and valve power loss estimation based on detailed electro-magnetic simulation is of low speed. To solve this problem, a method of valve power loss estimation based on the detailed equivalent simulation model of MMC is proposed. Results of valve power loss analysis of 201-level 500MW MMC operating at 50Hz~1000Hz are presented. It is seen that the valve power loss of a MMC increased by 12, 40 and 93 % under 200Hz, 500Hz and 1000Hz operating frequency. The article concludes that in a device with isolated inner AC system, MMC operating at higher frequency will be more competitive than typical 50Hz/60Hz MMC with moderate increase of operating power loss and significant reduction of the size of the AC components.     

Fast valve power loss evaluation method for modular multi-level converter operating at high-frequency

There is no common accepted way for calculating the valve power loss of modular multilevel converter (MMC). The method based on analytical calculation is inaccurate to address the switching power loss while the method based on detailed electro-magnetic simulation is of low speed. To solve this problem, an accurate valve power loss evaluation method of MMC based on the detailed equivalent simulation model of MMC is proposed. A fast power loss evaluation method is then proposed by linking the PSCAD/EMTDC and Matlab files. Detailed valve power loss analysis of a 201-level 500MW MMC operating at 50Hz~1000Hz is then presented. Relationship between the valve power loss, power transfer level and operating frequencies are presented and fitted. Research results of this paper can be used as guidance for the application of medium and high frequency MMC.     

Supporting Product Family Design in a 3D CAD/PDM Integrated System

This paper addresses some key issues in supporting product family design in a 3 D CAD/ PDM integrated system and introduces the techniques developed or adopted in building the integrated system. The general architecture of a 3D CAD/PDM integrated system is organized as five tiers. Multi-agent technology is applied with a collaborative design environment. The rule-based product family architecture （ PFA ） and tabular layouts of article characteristics （TLAC） technique are applied to represent the knowledge for product families. They make the knowledge understandable, simplified and can be exchanged among heterogeneous information systems. A transparently concentric integrated mode is put forward to enable the heterogeneous processes to interact and communicate regardless of the language used to construct each process. With the mode, function calling and information exchanging among different processes are carried out via message translation/parse approach. Currently, the integrated system is implemented in the platform of Windows NT and 2000.     

SnO-SnO2 modified two-dimensional MXene Ti3C2Tx for acetone gas sensor working at room temperature

Acetone,as widely used reagents in industry and laboratories,are extremely harmful to the human.So the detection of acetone gas concentrations and leaks in special environments at room temperature is essential.Herein,the nanocomposite combining SnO-SnO2 (p-n junction) and Ti3C2Tx MXene was successfully synthesized by a one-step hydrothermal method.Because of the existence of a small amount of oxygen during the hydrothermal conditions,part of the p-type SnO was oxidized to n-type SnO2,forming in-situ p-n junctions on the surface of SnO.The hamburger-like SnO-SnO2/Ti3C2Tx sensor exhibited improved acetone gas sensing response of 12.1 (Rg/Ra) at room temperature,which were nearly 11 and 4 times higher than those of pristine Ti3C2Tx and pristine SnO-SnO2,respectively.Moreover,it expressed a short recovery time (9 s) and outstanding reproducibility.Because of the different work functions,the Schottky barrier was formed between the SnO and the Ti3C2Tx nanosheets,acting as a hole accumulation layer (HALs) between Ti3C2Tx and tin oxides.Herein,the sensing mechanism based on the formation of hetero-junctions and high conductivity of the metallic phase of Ti3C2Tx MXene in SnO-SnO2/Ti3C2Tx sensors was discussed in detail.     

基于DSP的信息加密技术在工业中的应用

随着工业信息技术的飞速发展,工业上传输数据的安全性越来越差,而数据加密是保证信息安全的一种有效手段。探讨了采用DES和RSA混合加密方式实现计算机网络通信中的信息安全的方案。     

Corrosion resistance and antibacterial effects of hydroxyapatite coating induced by polyacrylic acid and gentamicin sulfate on magnesium alloy

Magnesium(Mg)alloys have attracted considerable research attention as potential biocompatible implant materials.However,the major barriers to the extended use of such medical devices are the possibility of high corrosion rate and implantassociated infections.To solve them,a novel polyacrylic acid(PAA)/gentamicin sulfate(GS)-hydroxyapatite(HAp)coating was synthesized by a one-step hydrothermal deposition method.Characteristics of functional coatings were investigated by SEM,FTIR and XRD.Corrosion properties of samples were evaluated by electrochemical and hydrogen evolution tests.Antibacterial activities of the coatings against Staphylococcus aureus(S.aureus)were measured by the plate-counting method.Results showed that the as-prepared HAp coating with dense and flawless morphologies could not only enhance the corrosion resistance of Mg alloys,but also improve the adhesion strength between the HAp coating and the substrate.In addition,the induction of the apatite coating during immersion confirmed the excellent mineralization ability of the HAp coating.Moreover,the obtained HAp coati ng possessed antibacterial properties and could prolong the release of GS.Thus,the PAA/GS-HAp coated Mg alloy could serve as a better candidate for biomedical applications with good anti-corrosion and antibacterial properties.     

In vitro corrosion of magnesium alloy AZ31 --- a synergetic influence of glucose and Tris

Biodegradable Mg alloys have generated great interest for biomedical applications. Accurate predictions of in vivo degradation of Mg alloys through cost-effective in vitro evaluations require the latter to be conducted in an environment close to that of physiological scenarios. However, the roles of glucose and buffering agents in regulating the in vitro degradation performance of Mg alloys has not been elucidated. Herein, degradation behavior of AZ31 alloy is investigated by hydrogen evolution measurements, pH monitoring and electrochemical tests. Results indicate that glucose plays a content-dependent role in degradation of AZ31 alloy in buffer-free saline solution. The presence of a low concentration of glucose, i.e. 1.0 g/L, decreases the corrosion rate of Mg alloy AZ31, whereas the presence of 2.0 and 3.0 g/L glucose accelerates the corrosion rate during long term immersion in saline solution. In terms of Tris-buffered saline solution, the addition of glucose increases pH value and promotes pitting corrosion or general corrosion of AZ31 alloy. This study provides a novel perspective to understand the bio-corrosion of Mg alloys in buffering agents and glucose containing solutions.