THE INVESTIGATION OF DIFFERENT POPULATION＇S TRANSFUSION-TRANSMITTED VIRUS-DNA IN SHAANXI PROVINCE

Objective To investigate transfusion transmitted virus (TTV) infection among population of different groups in Shaanxi Province. Methods A nested polymerase chain reaction (PCR) with primers from ORF1 of TTV genome was established to detect TTV-DNA in serum of the patients. Results TTV-DAN was detected in the sera of 3 of 50 cases of general population(6％), 2 of 30 cases of vocational blood donors(6.7%),21 of 97 cases with Type B hepatitis (21. 6％), 9 of 35 cases of Type C hepatitis (25. 7％),and 23 of 40 cases with non-A～ non-G hepatitis (57.5 ％ ). Conclusion There is TTV infection among general population in Shaanxi Province. TTV may be an impor- tant agent to cause non-A～non-G hepatitis. And the patients with HBV or HCV can have overlapping TTV infection.     

土-承台动力相互作用对砂土场地桩基桥梁地震反应的影响

在桩基桥梁的地震反应分析中,桩-土动力相互作用是个重要的问题,而对于采用低桩承台基础的桥梁,承台埋在土面以下,还存在土与承台之间的动力相互作用。目前,地震反应分析中一般不考虑土-承台动力相互作用的影响,相关研究也很少。为此,利用OpenSees有限元分析程序,基于p-y曲线建立了土-结构一体化桩基单墩模型,选择40条实际岩石场地地震记录作为输入,开展了考虑土-承台动力相互作用的桩基桥梁地震反应分析。结果表明,考虑土-承台动力相互作用后,结构的基本周期会减小,墩底曲率会明显增大,桩顶曲率会大幅减小,但墩顶位移的减小可以忽略。     

砂型铸造高锰铝青铜成分优化的数据分析

含镍高锰铝青铜ZCuAl8Mn13Fe3Ni2由于组成该合金的化学元素较多,且这些元素对机械性能的影响各不相同,研究如何对化学成分进行优选以得到优异的机械性能有着重要的意义。基于大量砂型铸造实际生产数据,采用MATLAB进行多元线性回归建模,分别建立了σb、δ5、HB与Al、Mn、Fe、Ni成分之间的线性回归方程。对方程的复相关系数、显著性及估计方差进行了检验,确认了回归方程的有效性。对真值及由回归方程得到的估计值采用分层逼近法加以筛选,经对比分析并结合丰富的实践经验,给出了化学成分的优选范围。还对ZQAl14-8-3-2的化学成份与机械性能之间的对应关系进行了探讨,并给出了修正的化学成份范围,即,Al:7.3%～8.6%;Mn:12.5%～14.5%。     

对流扩散方程的特征线MWLS算法

针对对流扩散方程,采用无网格法中的移动最小二乘近似方案与加权最小二乘法离散方案,结合特征线法,构造了特征加权最小二乘无网格算法(MWLS),并进行了数值试验验证.新算法克服了传统数值方法求解动态问题网格限制的缺陷,摆脱了在空间域上离散受制网格的束缚,不需要网格的初始划分或重构.试验结果显示,本算法可以达到与有限元求解几乎相同的结果,体现了不失精确度但却方便实用的优点.     

Association between the -1562 C/T polymorphism in the MMP-9 promoter and phenotype of esophageal squamous cell carcinoma in northern Chinese population

Objective To conduct a case-control study on the association of the nucleotide polymorphisms in the promoter region of the matrix metalloproteinase-9 (MMP-9) gene with phenotype of esophageal cancer. Methods All subjects were unrelated residents in northern regions of China. Polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) analysis was used to determine the MMP-9 genotypes. Results The overall distribution of genotypes in the patients was not different from that in the controls (OR=0.77, 95% CI=0.45-1.34; P=0.36). There were no significant differences between the patients and the control subjects in terms of the distributions of sex and age, smoking status, alcohol dependence, pickled diet status, or history of environmental exposure. The patients were further examined with stratifications by age, sex, grade, depth of tumor invasion, lymphatic invasion, venous invasion and TNM staging. The results showed no pronounced association among the stratifications. Conclusion There is no significant association between the MMP-9 single nucleotide polymorphism genotypes and phenotype of esophageal cancer.     

钢板弹簧三连杆模型参数辨识研究

钢板弹簧三连杆模型结构能够准确描述悬架垂直刚度特性,适用于计算路面载荷及平顺性分析.应用有限元软件计算钢板弹簧悬架刚度特性及导向特性,以此为基础通过集成优化方法及逆向求解方法辨识三连杆模型参数,并通过纵向力工况验证了模型的正确性.     

公司交通政策的最佳实践——以比利时为例

公司是通勤交通的主要创造者,在与交通相关的讨论中,公司扮演着重要角色。近几年,公司提出了多种政策措施,以改善员工的出行条件,但其愿景与行动通常被研究文献所忽视。为了讨论比利时公司在交通政策方面的最佳实践,分析了现有研究成果和比利时的两次大规模通勤交通调查。首先,对公司进行分类,以便确定在推广替代交通方式方面受员工欢迎的公司。然后,通过量化分析确定交通政策的最佳实践。结果显示,最佳替代交通方式取决于公司特征;自行车交通最适合小型工作场所,大型工作场所和位于建筑密集区或市中心的公司则更适合推广公共交通;在公司交通管理中,财务激励、设施提供、信息传播和停车管理均起重要作用。     

Towards improved port capacity investment decisions under uncertainty: a real options approach

ABSTRACT

Port activity plays an important role in facilitating international trade. Sufficient capacity is indispensable for a port to attract flows to a region and retain them. The capacity decision is the result of a trade-off between investment and waiting costs. Traditional methods to value expansion projects do not deal adequately with managerial flexibility in the face of uncertainty from different sources in the complex port environment. In this paper, real options (RO) models are identified as an alternative method to making project valuations and investment decisions, as they attribute the correct value to managerial flexibility under uncertainty. In order to be able to build and use such RO models for port capacity investment decisions, the sources and implications of uncertainty in the port and the different RO model specifications need to be understood. To this end, both the literature about uncertainty in the port context and the literature about real options models are reviewed in order to provide researchers who want to build their own decision-making models, with the necessary knowledge of both fields. The review makes clear that the complex interactions in and competition between the logistics chains and their actors coming together in ports have significant impacts on port capacity. Uncertainty is also caused by uncertain international trade flows and changes in legislation following new technologies and environmental impacts. An analysis of the components of some general RO models shows how the options of flexible output, investment size and timing are valued by RO models in a setting with demand uncertainty. Moreover, the review presents researchers with insights in how to deal with cooperative and competitive interactions in the chain, time to build, cyclical markets and legislation changes. It also shows how to value the expansion and the phased investment options. The new insights resulting from this review are subsequently combined in a framework that serves as a guideline to build RO models for port capacity investments. Finally, an exemplifying application of the framework is used to build an actual port capacity investment decision model.     

Simple adaptive filtering scheme to improve measurement accuracy of gyroscope on angular motion base

The objective of this work is to improve the measurement accuracy of a gyroscope on a angular motion base with a simple adaptive filter scheme. Two main topics are highlighted in this work. The first topic is to show building a dual-process model employed for the conventional Kalman filter. The second topic is to show developing a modified noise adaptive algorithm when measurement noise and process noise are unknown. The experimental results are presented to show that the simple adaptive filtering scheme outperforms the other conventional scheme in this paper in terms of noise reduction.     

非饱和黄土结构强度特性的试验研究

分析了非饱和黄土强度的组成和结构强度的来源,通过常规三轴试验对非饱和黄土的结构强度和抗剪强度规律进行了研究。结果表明:非饱和黄土的结构强度可用其天然结构破坏时所丧失的强度表示;同一含水率下结构强度随围压的增大而增大,在同一围压下结构强度随含水率的增加而逐渐减小,呈较好的幂函数关系;结构强度与其粘聚力之间有显著的线性相关关系。