光纤流量计的稳定性分析

分析了反射式光纤涡街流量计在管道内流体的流动为层流和紊流时光纤的受迫振动，分析表明在层流和条流状态下，光纤所受张力与单位光纤长度的质量比满足Ｔ／ρ＞＞（０．４ｖＤ／ｄ）￣２时，光纤的振动及反射回到光纤的光强变化只与外力变化频率有关。实验结果已证实了本文分析的正确性。     

Gamma-Maxwell distribution

A new two-parameter distribution, the gamma-Maxwell distribution, isproposed and studied. We generate the new distribution using the gamma-G generator of distributions. The proposal distribution can be seen as an extension of the Maxwell distribution with more flexibility in terms of the distribution asymmetry and kurtosis. We study some probability properties, discuss maximum-likelihood estimation and present a real data application indicating that the new distribution can improve the ordinary Maxwell distribution in fitting real data.     

Spatial effects on individual social capital: Differentiating the constraints of local occupational structures

Recent studies have paid more attention to how position-generated social capital varies by an individual’s characteristics, and less to how geographical distributions of occupations may constrain position-specific connections. By integrating two national surveys from the United States, we differentiate the extent to which individual social capital fluctuates by occupational compositions at the county, metropolis, and state levels. Multilevel analyses show that when more people at all three levels work in education, training, and library occupations, residents have a greater chance to gain access to professional-type resources. Similar spatial effects on farming and production resources, however, are more apparent at the county level. Not only does the association between individual social capital and local occupational structures vary across different occupations, but the magnitude of such spatial effects also differs by the scope of the geographical areas. The findings underscore how contextual factors and geographical location may contribute to building occupation-specific network resources.     

The intersection of class origin and immigration background in structuring social capital: the role of transnational ties

The study investigates inequalities in access to social capital based on social class origin and immigration background and examines the role of transnational ties in explaining these differences. Social capital is measured with a position generator methodology that separates between national and transnational contacts in a sample of young adults in Sweden with three parental backgrounds: at least one parent born in Iran or Yugoslavia, or two Sweden‐born parents. The results show that having socioeconomically advantaged parents is associated with higher levels of social capital. Children of immigrants are found to have a greater access to social capital compared to individuals with native background, and the study shows that this is related to transnational contacts, parents’ education and social class in their country of origin. Children of immigrants tend to have more contacts abroad, while there is little difference in the amount of contacts living in Sweden across the three groups. It is concluded that knowledge about immigration group resources help us predict its member's social capital, but that the analysis also needs to consider how social class trajectories and migration jointly structure national and transnational contacts.     

类矩形双肢钝体涡致振动和气动抑振机理

针对具有类矩形双肢钝体断面拱肋的大跨度拱桥在风洞试验过程易出现大幅涡激振动问题，沿拱肋模型表面进行动态风压同步测量及基于POD算法的本征气动力荷载分布模式分解，获得了涡振发生时对于周期性涡激力具有最大贡献的气动力荷载作用位置，初步揭示出此类断面涡激动发生时的局部气动力荷载作用机制。以上海卢浦大桥和肇庆西江特大桥此类具有双肢钝体断面拱桥为工程实例，结合涡激气动力沿拱肋周向时空气分布特征，提出并以二维悬吊节段模型风洞试验验证了拱肋断面多种有针对性的气动控制措施；结合实际桥梁拱肋的三维空间效应，利用全桥气弹模型     

Generalized Linear Models

The importance of random number generators has increased over the years. This follows from the fact that contemporary research methods rely more and more on simulation and the increased importance of encryption technology. The output of a random number generator is created by either an algorithm or a physical device. The most popular method for random number generation is through the use of an algorithm. This article presents a new category of physical random bit generator that is packaged by several manufacturers. A statistical analysis of the output from the generators is given.     

CAI函数图形发生器FGG的设计与实现

介绍在Ｗｉｎｄｏｗｓ环境下用ＢｏｒｌａｎｄＣ＋＋３．１开发的通用函数图形发生器的结构和功能，讨论了实现中的表达式求值算法和图形生成算法。ＦＧＧ的主要特点是，对输入的任意一元、二元函数表达式可直接生成对应的二维和三维图形。ＦＧＧ作为ＣＡＩ写作工具的支撑软件，可用于ＣＡＩ课件的开发及演示。     

考虑黏性及压缩效应的旋涡运动特性

采用扩散速度法处理黏性作用项的离散涡法，数值模拟了旋涡在黏性不可压流场中的运动；推导了可压缩流中的旋涡运动方程，对不可压缩流中的Biot-Savart方程进行了可压缩修正，进而用离散涡方法求解出非定常、不稳定、可压缩流场中的旋涡运动。分析了胀量及黏性扩散作用对旋涡运动的影响，通过大量长时间行为的数值试验得出了一系列结果。结果表明：为了真实地反映旋涡在实际流体中的运动规律，必须考虑黏性及压缩性的影响。     

基于DDS和FPGA的多功能信号发生器设计

根据直接数字频率合成技术,以FPGA为核心,设计了一种便携式多功能信号发生器,可产生正弦波、方波、三角波、锯齿波等信号。通过仿真及硬件实验表明,该信号发生器具有信号频率误差小、分辨率高、体积小、质量轻等优点。