基于太阳能热驱动甲烷重整制氢的燃料电池发电系统性能研究

该文采用Aspen Plus软件建立膜反应器重整制氢及燃料电池模型,根据拉萨某日太阳能直接辐射强度（DNI）变化计算太阳能可供使用的能量,作为外热源输入重整系统,并分析反应温度、水碳比（S/C）及DNI对该系统各性能指标的影响,性能指标包括甲烷转化率、H₂收率、电池功率及电压、太阳能转换为氢能的效率。结果表明：反应温度为500 ℃,S/C为2.5时有利于太阳能甲烷湿重整反应;系统日性能结果显示在某日10:00—20:00时,电池输出功率120 kW,太阳能-化学能转化效率0.368,系统发电效率0.225。     

烟梗中果胶的酶法降解

烟梗中的果胶对卷烟感官质量有不利影响。为减少果胶含量,从4种酸性果胶酶中筛选出1种适用于降解烟梗中的果胶,并采用单因素实验方法分别考察了加酶量、料液比、pH、处理时间和温度5个因素对烟梗中果胶降解效果的影响。采用正交试验分析方法,对该果胶酶的作用条件进行了优化。结果表明:最优作用条件为:加酶量100 U/g,料液比1∶20,初始pH 3.0,处理时间8 h,温度45℃,此条件下烟梗中果胶的降解率可达42.38%。     

An empirical study of programming language trends

Predicting software engineering trends is a strategically important asset for both developers and managers, but it's also difficult, due to the wide range of factors involved and the complexity of their interactions. This paper reveals some interesting trends and a method for studying other important software engineering trends. This article trades breadth for depth by focusing on a small, compact set of trends involving 17 high-level programming languages. We quantified many of their relevant factors, and then collected data on their evolution over 10 years. By applying statistical methods to this data, we aim to gain insight into what does and does not make a language successful.     

Aging selectively impairs recollection in recognition memory for pictures: Evidence from modeling and receiver operating characteristic curves.

Young and older adults were tested on recognition memory for pictures. The Yonelinas high threshold (YHT) model, a formal implementation of 2-process theory, fit the response distribution data of both young and older adults significantly better than a normal unequal variance signal-detection model. Consistent with this finding, nonlinear z-transformed receiver operating characteristic curves were obtained for both groups. Estimates of recollection from the YHT model were significantly higher for young than for older adults. This deficit was not a consequence of a general decline in memory; older adults showed comparable overall accuracy and in fact a nonsignificant increase in their familiarity scores. Implications of these results for theories of recognition memory and the mnemonic deficit associated with aging are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

纤维微表处施工性能影响分析及对比研究

为对比分析纤维微表处施工性能与纤维种类、纤维掺量、油石比的关系,选取4种纤维,通过改变纤维掺量、油石比大小进行不同条件下的拌和试验、黏聚力试验。通过一系列试验结果可知:随着纤维掺量的增加,纤维微表处混合料的拌和时间逐渐缩短,黏聚力值逐渐增大,且不同纤维掺量有其最合适的用水量;对于纤维微表处施工性能,当纤维掺量为0.10%~0.25%,油石比为7.0%~7.5%时,施工性能最佳。     

Effects of RE3+ Ionic Radius on Monoclinic Phase Content of 8 mol% REO1.5 Partially Stabilized ZrO2 (RE = Yb,Y, Gd,and Nd) Powder Compacts after Annealing at High Temperature

Powders of zirconia doped with 8 mol% REO_1.5 (RE = Yb, Y, Gd, and Nd) were synthesized by using the sol–spray pyrolysis method. The effects of RE³⁺ ionic radius on monoclinic (m) phase content of powders were investigated. The XRD results showed that the metastable tetragonal (t′) phase underwent a complete phase change to form m and cubic (c) phases after a heat treatment of 50–100 h at 1450°C. A cation size‐dependent reduction in the m phase content of the REO_1.5 partially stabilized ZrO₂ powders was observed. The SEM–EDS analysis of the powders revealed that the RE³⁺ concentrations in the c phases decreased with decreasing the RE³⁺ ionic radius. These results indicate that the stabilizer concentration of the c phase can be attributed to RE³⁺ ionic radii, resulting in different m phase contents. Compared to the REO_1.5 single doped ZrO₂, the m phase contents of 8 mol% (RE_0.5Yb_0.5)–ZrO₂ (RE = Y, Gd, and Nd) powders were significantly reduced. The results prove that the stabilizer with a lower RE³⁺ size is effective in reducing the m phase content of partially stabilized ZrO₂ after annealing at high temperatures.     

基于DSP全数字控制系统开关磁阻电机的研究

介绍了一种基于DSP、CPLD、PLC的开关磁阻电机全数字控制系统,并结合一个15kW的SRM样机对此系统进行了分析和试验.试验结果证明,系统综合性能良好.     

基于单片机的变频系统Profibus通讯

介绍Profibus现场总线的基本特点,给出了一种用单片机实现变频系统Profibus通讯的方案,完成实时通讯和控制功能,缩短了开发周期,有利于提高产品的数字化程度.     

基于奇异值特征的图像预处理及人脸识别

从增强图像的分类信息角度出发,对人脸图像做频域上的带通滤波预处理,来 提高奇异值特征的分类性能．给出了一组圆形滤波函数,并使用遗传算法来选择可分性较大 的频段,设计了染色体的表示方式和适应度的求法．实验证明预处理后奇异值特征的分类效 果比处理前有较明显的提高．     

图像非加性隐写综述

图像非加性隐写不仅能更好地维持图像元素的分布,而且具有较高的抗检测性能.首先对图像非加性隐写方法进行了梳理,将其分为两大类:非加性失真设计和非加性隐写编码设计.进一步将非加性失真设计总结为3类:基于理论模型、基于修改原则和基于对抗检测的方法,对这些方法进行了对比.最后分析了非加性隐写面临的困难问题和未来的发展思路.