Enclosure results for quasilinear systems of variational inequalities

In this paper we consider systems of quasilinear elliptic variational inequalities, and prove the existence of minimal and maximal (in the set theoretical sense) solutions within some ordered interval of an appropriately defined pair of sub- and supersolutions. We show that the notion of sub- and supersolutions of variational inequalities introduced here is consistent with the usual notion of sub-supersolutions for (variational) equations. For weakly coupled quasimonotone systems of variational inequalities the existence of smallest and greatest solutions is proved.     

风力发电机组变速恒频控制系统研究

全面介绍了一种最新应用于风力发电中的新型电机—无刷双馈电机，并分析了这种新型电机作变速恒频运行的原理并对这种电机进行了动态特性仿真研究，给出了形式简洁的控制方程和易于实现的控制方案。     

Cu~+、Ag~+、Au~+与乙硫醇的气相化学反应

利用激光溅射 分子束的技术 ,结合反射飞行时间质谱计 ,研究了Cu+、Ag+、Au+与乙硫醇的气相化学反应。结果显示这三种金属离子与 (CH3 CH2 SH) n 反应形成一系列团簇离子M+(CH3 CH2 SH) n,且团簇离子尺寸不一样。Ag+、Au+与乙硫醇的反应还生成了 (CH3 CH2 SH) +n ,由此推测Cu+、Ag+、Au+与乙硫醇团簇的反应存在两种通道 ,一种通道是生成M+(CH3 CH2 SH) n,另一种是生成 (CH3 CH2 SH) +n 。Cu+、Au+与乙硫醇的反应还生成了M+(H2 S) (M =Cu、Au) ,但是实验中没有观察到Ag+(H2 S) ,理论计算表明Ag+(H2 S)很不稳定。另外 ,分析产物离子M+(CH3 CH2 SH) n 的强度发现 ,n =1～ 2之间存在明显的强度突变现象     

A note on the unsteady boundary layers over a flat plate

The unsteady boundary layer over a semi-infinite flat plate was investigated in this paper. The flow involves the unsteady flow over a flat plate with leading edge accretion or ablation. The momentum boundary layer was further analyzed and it was shown that the leading edge ablation had a similar effect to the wall mass injection or upstream wall movement making the fluid blown away from the wall. The thermal boundary layer of the same flow was also studied. Results show that the leading edge accretion or ablation can greatly change the fluid motion and the heat transfer characteristics.     

Influence of the Type of a Ligand on the Intensity of Luminescence of Ln3+ Ions in Aqueous Solutions

The luminescence characteristics of hydrated Ln³⁺ ions and their complexes with some acidic ligands have been investigated. The possibility of determining the stability of the complexes of lanthanides in solutions from the intensity of luminescence bands is shown. The influence of the characteristic features of the f-electron shell of Ln³⁺ on the formation of the spectrochemical series is discussed.     

合作联盟资源集成计划一种新方法

合作联盟里，资源集成计划往往是联盟成员群体谈判博弈的结果。本以两人博弈为例，对联盟的资源集成计划给出一个谈判博弈模型，能够较好地模仿和反映合作联盟资源整合计划的制订过程。     

期货经纪公司保证金的一种确定方法

本文基于马尔可夫链在存储论中的应用，结合Ergodic定理，得到确定期货经纪公司保证金的Ergodic模型，即一个双目标规划问题，然后应用乘积最大化准则，将该模型转化为单目标规划问题来求解。该方法考虑期货经纪公司承担的风险和对投资者的吸引程度，为保证金的确定提供新的思路。     

恩格尔系数衡量城镇居民生活水平适用性

根据我固1980年和2000年恩格尔系数所反映的各省(市)居民生活水平资料，发现两个不同时期其真实性有很大差异，分析了造成这种差别的原因：(1)职工非现金福利收入的增加；(2)少数职工的非法收入的大量增加；(3)居民饮食结构的改变；(4)物价上涨的影响；(5)恩格尔系数本身存在技术问题；(6)抽样调查本身存在问题，提出用一种“新系数”来衡量城镇居民生活水平，其优点是：(1)不受各地区实际支出，即人为控制调节的影响；(2)不需用其他指标作解释，直观性强；(3)因可以扣除物价因素，它不受物价波动的影响；（4)调查户填报和计算简易方便。可扩大样本调查量，提高反映住户总量可靠性。     

Effects of diamines and their fluorinated groups on the color lightness and preparation of organosoluble aromatic polyimides from 2,2‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]‐hexafluoropropane

To investigate the position and amount of the CF₃ group affecting the coloration of polyimides (PIs), we prepared 2,2‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]hexafluoropropane ( 2 ) with four CF₃ groups with 2‐chloro‐5‐nitrobenzotrifluoride and 2,2‐bis(4‐hydroxyphenol)hexafluoropropane. A series of soluble and light‐colored fluorinated PIs ( 5 ) were synthesized from 2 and various aromatic dianhydrides ( 3a – 3f ). 5a – 5f had inherent viscosities ranging from 0.80 to 1.19 dL/g and were soluble in amide polar solvents and even in less polar solvents. The glass‐transition temperatures of 5 were 221–265 °C, and the 10% weight‐loss temperatures were above 493 °C. Their films had cutoff wavelengths between 343 and 390 nm, b* values (a yellowness index) ranging from 5 to 41, dielectric constants of 2.68–3.01 (1 MHz), and moisture absorptions of 0.03–0.29 wt %. In a comparison of the PI series 6 – 8 based on 2,2‐bis[4‐(4‐aminophenoxy)phenyl]hexafluoropropane, 2,2‐bis[4‐(4‐amino‐2‐trifluoromethylphenoxy)phenyl]propane, and 2,2‐bis[4‐(4‐aminophenoxy)phenyl]propane, we found that the CF₃ group close to the imide group was more effective in lowering the color; this means that CF₃ of 5 , 7 , and 8f was more effective than that of 6c . The color intensity of the four PI series was lowered in the following order: 5 > 7 > 6 > 8 . The PI 5f , synthesized from diamine 2 and 4,4′‐hexafluoroisopropylidenediphthalic anhydride, had six CF₃ groups in a repeated segment, so it exhibited the lightest color among the four series. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 922–938, 2003     

基于DS/AHP的供应商选择方法

供应商选择方法有很多种，在众多的方法中层次分析法以能够将定性指标定量化而被广泛应用于供应商选择决策中。考虑到供应商选择问题中包含有很多的不确定性而证据理论在处理不确定问题又有着独特的优点，因此本文采用了一种由层次分析法和证据理论结合而产生的DS／AHP决策方法，并将其应用于供应商选择决策问题中，该方法综合了层次分析法和证据理论的优点，可以更科学的进行供应商选择决策，最后通过一个例子说明这种方法在供应商选择中的应用。