纳米复合金属陶瓷模具材料的研究进展

纳米复合金属陶瓷材料不仅具有较好的综合机械性能,如高强度、高硬度、耐高温、耐磨损,而且具有较好的化学稳定性、抗氧化性能和耐腐蚀性能,在模具制造方面具有广阔前景.本文综述了纳米复合金属陶瓷材料的研究现状及存在问题,并指出了今后研究的发展趋势.     

Method of Predicting Water Content in Crude Oil Based on Measuring Range Automatic Switching

Water content in output crude oil is hard to measure precisely because of wide range of dielectric coefficient of crude oil caused by injected dehydrating and demulsifying agents.The method to reduce measurement error of water content in crude oil proposed in this paper is based on switching measuring ranges of on-line water content analyzer automatically.Measuring precision on data collected from oil field and analyzed by in-field operators can be impressively improved by using back propogation (BP) neural...     

行为NA的随机变量阵列的收敛性

利用NA序列的一个矩不等式,研究了行为NA的随机变量阵列,证明了1/n1p∑ni=1Xni平均收敛于0、完全收敛于0、几乎必然收敛于0、依概率收敛于0的等价性.     

Effect of variation in gas distribution on explosion propagation characteristics in coal mines

In order to investigate the effect of variation in the distribution of gas on explosion propagation characteristics in coal mines, experiments were carried out in two different channels with variation in gas concentration and geometry. Flame and pressure transducers were used to track the explosion front velocity. The flame speed (Sf) showed a slight downward trend while the methane concentration varied from 10% to 3% in the experimental channel. The peak overpressure (Pmax) dropped dramatically when com-pared with normal conditions. As well, the values of Pmax and Sf decreased when the methane concentration dropped from 8% to 6%. The flame speed in the channel, connected to a cylinder with a length varying from 0.5 to 2 m, was greater than that in the normal channel. The peak overpressure was also higher than that under normal conditions because of a higher flame speed and stronger pressure piling up. The values of Pmax and Sf increased with an increase in cylinder length. The research results indicate that damage caused by explosions can be reduced by decreasing the gas concentration, which should be immediately detected in roadways with large cross-sections because of the possibility of greater destruction caused by more serious explosions.     

Additive-aided electrochemical deposition of bismuth telluride in a basic electrolyte

A new basic electrolyte with two cationic plating additives,polydiaminourea and polyaminosulfone,was investigated for the electrochemical deposition of the bismuth telluride film on a nickel-plated copper foil.Tellurium starts to deposit at a higher potential(-0.35 V) than bismuth(-0.5 V) in this electrolyte.The tellurium-to-bismuth ratio increases while the deposition potential declines from-1 to-1.25 V, indicating a kinetically quicker bismuth deposition at higher potentials.The as-deposited film featu...     

Phase field simulation of the 180°domain-switching process in PbTiO_3 single crystal under an antiparallel electric field

The process of 180°domain switching in PbTiO_3 single crystal under an antiparallel electric field was investigated by the three-dimensional phase field simulation,especially the effect of electric field on the type and duration of domain switching.It is found that the polarization reversal of domains takes place under an antiparallel electric field in PbTiO_3 single crystal.The results of the phase field simulation indicate that there is only 90°domain switching under a weak electric field.With the rise...     

基于WiFi的井下无线智能终端的设计

WiFi技术以其组网方便、易于扩展等优势,越来越受到广泛关注,有着广阔的应用前景。本文设计了基于ARM9的WiFi智能终端,利用WiFi无线局域网技术实现了语音通信、数据采集和远程监控等功能,可用于矿井语音、视频通信和环境的实时监测。     

对建筑本土化表达的探索——以南京陵园小筑建筑改造为例

结合南京陵园小筑建筑改造方案的设计,在充分考虑了当地气候特点、环境特征和建筑文脉后,从总平面的规划、建筑单体设计、建筑造型和材料使用等方面,对建筑的本土化表达进行了探索和研究。同时提出一些新的见解,倡导建筑师在设计实践中对我国地域文化与建筑设计的结合进行积极的思考和运用。     

路基边坡面力学试验参数处理方法研究

介绍了半填半挖路基挖填交接面的形式分类以及相应的变形破坏形式,同时提出采用随机-模糊统计法处理路基稳定性。半挖半填式路基是高速公路施工中一种常见的修筑方式,其稳定性的好坏取决于挖填交接面的形式及其岩体力学性质。表明了模糊统计处理方法优于传统的随机处理方法,通过工程应用实例表明该方法可靠合理,具有广泛推广的价值。     

水处理中超滤膜不能去除水中溶解态有机物

根椐天然水中有机物的形态和分子量分布状况,对比水处理中常用的超滤膜截留分子量,认为给水处理中超滤不能去除天然水中溶解态有机物.