200 km/h电力机车气动性能风洞试验与数值模拟

采用模型风洞试验和数值计算方法研究了200 km/h机车外形的气动性能.试验风洞为FD-09单回流低速风洞,模型缩尺比为1:8.873.数值计算采用流体动力学软件FLUENT,数学模型为三维粘性不可压缩流体雷诺时均方程和κ-ε双方程湍流模型.数值模拟结果与模型风洞试验结果基本吻合.在此基础上对多个外形的设计参数进行了优化,并对优化后的模型流场作了数值计算,得出了一些有益的结论.     

脉冲混合系统关于两度量的最终稳定性

给出了脉冲混合系统关于两度量的最终稳定性的定义,利用分段连续Lyapunov函数,得到了脉冲混合系统关于两度量的一致最终稳定性的结果,最后用实例对所得结果进行了说明.     

大直径掺钕铌酸锂晶体生长及其光学性能研究

在LiNbO3多晶料中依次掺入0.2mol%,0.5mol%和1.0mol%的钕,采用我们自主开发的计算机控制直拉法生长大直径Nd:LiNbO3晶体,测试了晶体的紫外-可见吸收光谱、荧光光谱和红外吸收光谱。由紫外-可见吸收光谱确定泵浦光波长,由荧光光谱确定激光振荡波长;采用X射线荧光光谱分析法测量了Nd:LiNbO3晶体中钕的有效分凝系数,结果是Nd:LiNbO3晶体中钕的有效分凝系数随着钕掺杂浓度的增加而减小。     

企业总产值的组合预测方法与应用

为了选择灰色预测系统的最佳解释变量,并使其代表原始数据的绝大部分信息,将主成份分析方法与灰色系统理论进行有机地结合,形成一种组合预测方法。主成份的作用就在于对原始数据寻求基本结构、简化观测系统,并用一个有代表性的变量子集来解释整个问题,使GM(1,h)模型反映出影响某个经济现象的关键因素,更加有效地揭示了系统的发展趋势和动态变化规律,该方法具有很强的可靠性和实用性。     

一类用h进制小数表示的无理数

设g、h均是大于1的整数,N=(n_1,n_2,n_3,…)是非负整数的无穷序列,(g~n)n是整数g~n的h进制表示,令a_(ngN)=0.(g~(n_1))n(g~(n_2))n(g~(n_3))n…为由(g~(n_1))n,(g~(n_2))n,(g~(n_3)),…连接而成的h进制小数。文献[1]—[5]分别证明了,当序列N满足一定的条件时,a_(ngN)是个无理数。本文得到了使a(ngN)成为无理数的更广泛的条件。     

Axillary 5α-androst-16-en-3-one in men and women: Relationships with olfactory acuity to odorous 16-androstenes

Summary Axillary 5h663317065205472/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-androst-16-en-3-one (5h663317065205472/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-androstenone) levels were found to be significantly higher in men than in women but do not vary between left and right axillae, are not related to age, handedness or degree of hirsutism (in women) nor to anosmia to this steroid. In men (but not in women), levels are related linearly to axillary cholesterol concentrations but not to squalene. Olfactory thresholds for 5h663317065205472/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-androstenone varied widely, the lowest recorded being 0.2 ppb, but there was no difference in thresholds between men and women. Women (70%) found the smell h663317065205472/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">repellanth663317065205472/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> but anosmia did not differ greatly between men and women (9–20%). Anosmia to the smell of 5h663317065205472/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-androst-16-en-3h663317065205472/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-ol was most marked in women (90%) rather than in men (45%). Axillary 5h663317065205472/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">-androstenone values were generally consistent with the h663317065205472/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">muskyh663317065205472/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> or h663317065205472/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">strongh663317065205472/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> smells of male axillary extracts, compared with the h663317065205472/xxlarge8216.gif" alt="lsquo" align="BASELINE" BORDER="0">sweeth663317065205472/xxlarge8217.gif" alt="rsquo" align="BASELINE" BORDER="0"> smell of those from female subjects.Supported by the Herbert Dunhill Trust.     

Lack of tolerance development to tumor necrosis factor α inside the central nervous system

Tumor necrosis factor h117n3332m0880/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> (TNFh117n3332m0880/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">) was repeatedly microinfused into the lateral ventricle of guinea pig brains at a dose of 200 ng, 4 times within 150 min, at intervals of 3 days. In comparison to guinea pigs infused with solvent according to the same time schedule, the animals responded to TNFh117n3332m0880/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> with pronounced fevers. The quantity of the fever response was the same after each of the 4 microinfusions of TNFh117n3332m0880/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">. Three days after the last infusion of TNFh117n3332m0880/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0"> or solvent all animals received an intramuscular injection of bacterial lipopolysaccharide (LPS). The fever in response to LPS was the same in both groups. Thus, the reported development of tolerance to repeated systemic administration of TNFh117n3332m0880/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">^1–3 does not develop inside the blood-brain barrier. Also, the febrile response to LPS is not influenced by repeated central pre-treatment with TNFh117n3332m0880/xxlarge945.gif" alt="agr" align="BASELINE" BORDER="0">, whereas repeated peripheral treatment does have an effect.     

基于对称模糊数和最优h值线性回归模型的质量功能展开研究

模糊线性回归参数h决定模糊系数的可能性分布,影响模型的系统可靠性.分析了含有参数p的对称模糊数的模型,得出质量功能展开中具有最优h值的函数关系.当参数p给定时,考虑系统模糊性和系统隶属度两个因素,依据模糊线性回归模型系统可靠性最大的原则,得到最优h值;并将该理论应用于质量功能展开的实例,选取有代表性的3个p值,分别对应二次根型、三角型和抛物型对称模糊数进行讨论,得到对应的最优h值.在最优h值的前提下,分析对应的系统模糊性和可靠性的变化规律,通过对比分析,得到系统可靠性最大的函数关系.     

Reflection Talbot Effect and Application

The reflection Talbot effect under the illumination of Gaussian spherical wave and plane wave is observed on 1D and 2D photonic crystal of silicon prepared by nanosecond laser. It is found that the distance between two adjacent Talbot images increases lineally with increasing of image distance as well as amplification of Talbot images under the illumination of Gaussian spherical wave. The result of theory is coincident with that of experiment, which shows that selecting suitable wavefront shape of input field can enlarge the amplification rate and improve the resolution of Talbot imaging. The reflection Talbot effect will have a lot of good application in microscopy of micro-fabrication on silicon, such as detecting period structures of plasma on line of PLD fabricating.