岩土工程中试验数量与可靠指标的关系

基于小样本理论,分析了岩土工程中试验数量与参数统计均值间的关系、参数统计均值与可靠指标间的关系、试验数量与可靠指标间的关系,指出试验数量对参数统计均值及可靠指标均有影响.在相同的置信度及变异系数情况下,试验数量越小,参数统计均值及可靠指标的相对误差就越大.随着试验数量的增加,这种影响程度随之减弱.试验数量对可靠指标的影响还与参数的敏感性有关,参数的敏感性系数越大,在相同的置信度及变异系数情况下,试验数量对可靠指标的影响程度也越大.因此,可靠指标不是定值,它与试验数量、参数统计时的置信度及参数的变异系数有关.在进行岩土工程的可靠度分析时,一定要将概率的概念贯穿于从试验设计到可靠度分析的全过程,而不仅仅局限于可靠指标的分析计算阶段.     

Progress in entransy theory and its applications

The entransy and entransy dissipation extremum principle proposed have opened up a new direction for the heat transfer optimi-zation. The emergence and development of entransy theory are reviewed. Entransy theory and its applications are summarized from several aspects, such as heat conduction, heat convective, heat radiation, heat exchanger design and mass transfer, etc. The emphases are focused on four aspects, i.e., the comparison between entropy generation rate and entransy dissipation rate, the combination of entransy dissipation extreme principle with finite time thermodynamics, the combination of entransy dissipation extreme principle with the heat conduction constructal theory, and the combination of entransy dissipation extreme principle with the heat convective constructal theory. The scientific features of entransy theory are emphasized.     

An equation of entransy transfer and its application

Entransy is a physical quantity describing heat transfer ability, and heat transfer is accompanied by entransy transfer. Thermal energy is conserved in its transfer process, while entransy is dissipated because of the irreversibility of its transfer process. As a result, entransy transfer must have its rules which are different from those of thermal energy transfer. Based on the definition of entransy, an entransy transfer equation is derived, which describes the entransy transfer processes of a multi-component viscous fluid subject to heat transfer by conduction and convection, mass diffusion and chemical reactions. The expressions of entransy flux and entransy dissipation are obtained simultaneously, and their physical mechanism is clarified. And further, the theory and method of optimizing heat transfer applying the entransy transfer equation to the steady-state convection heat transfer process are expounded. The minimum thermal resistance principle and the entransy dissipation extremum principle are obtained by applying the steady-state entransy transfer equation to the steady-state convection heat transfer process. The cases of the single-component steady-state convection heat transfer and the steady-state heat conduction show the application of the theory and method.     

磷酸掺杂对聚苯胺电导率及微观结构的影响

对磷酸掺杂的聚苯胺进行了电导率测试，并从微观结构上对这种变化进行探讨．结果表明：随着掺杂剂酸度的增加，大块状的聚苯胺消失，生成了结构更精细、平均粒径更小的聚苯胺，并且在整个微观结构上形成了聚苯胺隧道网化．掺杂有利于导电通道的形成，从而可以显著提高聚苯胺的导电性．     

和连通指数和色数的一个关系

目的研究简单图的和连通指数和色数的一个关系。方法对和连通指数删除一个最小度点的作用。结果与结论设图G的和连通指数为X(G),v是G中最小度的点,G-v是G中删除点v后得到的图,可证得结论 X(G)≥X(G-v)并且得到和连通指数X(G)和色数χ(G)的一个关系χ(G)≤2 X(G)。     

Entropy generation extremum and entransy dissipation extremum for heat exchanger optimization

The applicability of the extremum principles of entropy generation and entransy dissipation is studied for heat exchanger optimization. The extremum principle of entransy dissipation gives better optimization results when heat exchanger is only for the purpose of heating and cooling, while the extremum principle of entropy generation is better for the heat exchanger optimization when it works in the Brayton cycle. The two optimization principles are approximately equivalent when the temperature drops of the streams in a heat exchanger are small. Supported by Major State Basic Research Development Program of China (Grant No. 2007CB206901)     

二数列筛法及数的堆垒性和积性的关系

为进一步研究数的堆垒性质,基于爱氏筛法提出一种新的筛法——二数列筛法,运用2种筛法审查数,结果发现一个数被表示为2个素数的倍数之和形状的有关性质及其与数的积性之间存在着必然的关系,进而推导出大于6的偶数与相邻的奇数分别被表示为2个合数之和形状时其解的数量变化的规律,为证明相关的命题提供重要依据。     

符号与语境的关系

一切被赋予了人的意识的事物都是符号,而语境是符号意义相互＂溶解＂而形成的一种多维度的意向性场所。那么,符号和语境的关系怎样,它们以怎样的态势相依相存,本文尝试从现代语言学的角度分析符号与语境的关系,进而解释社会生活中的一些语言现象的产生。     

比喻与夸张的关系

人们对比喻和夸张的理解一般都囿于传统的认识，认为二者毫不相干。比喻跟夸张之间事实上存在着联系：喻体是相对于本体更为典型的事物，实质上起着放大本体相似点的作用，这就形成了事实上的夸张；间接夸张要通过比喻、比拟等修辞方式来实现，部分夸张中兼含有比喻。但作为修辞学上的两种辞格，比喻跟夸张又存在着一些不同。     

Relationship between science and technology

Do economic advances spring directly from fundamental scientific discoveries? The early history of the transistor suggests that the situation is not nearly so simple as this.     

Generalized thermal resistance for convective heat transfer and its relation to entransy dissipation

In order to further analyze and optimize convective heat transfer process further, the concepts of heat flux weighted average heat temperature and heat flux weighted average heat temperature difference in multi-dimensional heat transfer system were introduced in this paper. The ratio of temperature differ- ence to heat flux is defined as the generalized thermal resistance of convective heat transfer processes, and then the minimum thermal resistance theory for convective heat transfer optimization was devel- oped. By analyzing the relationship between generalized thermal resistance and entansy dissipation in convective heat transfer processes, it can be concluded that the minimum thermal resistance theory equals the entransy dissipation extremum theory. Finally, a two-dimensional convective heat transfer process with constant wall temperature is taken as an example to illustrate the applicability of generalized thermal resistance to convective heat transfer process analysis and optimization.     

皮质醇与运动训练关系研究

应用文献综述法，论述了不同运动负荷、不同运动项目中皮质醇的变化及影响皮质醇变化的非训练因素．用皮质醇监控运动训练，可以快速、准确地反映训练的强度和训练量以及运动员的机能状态，进而指导教练员和运动员调整运动负荷，合理安排训练内容．     

β-统计收敛与收敛的关系

利用β-统计收敛说明统计收敛、A-统计收敛、缺项统计收敛、λ-统计收敛及强统计收敛分别是β-统计收敛的特殊形式,并分别给予测度刻画.考察β-统计收敛与一般序列收敛之间的关系,得到统计收敛、λ-统计收敛及强统计收敛与收敛之间的等价描述.     

R-收敛因子和σ-收敛因子之间的关系

收敛速度是衡量一个最优化算法好坏的重要指标．1970年Ortega和Rheinboldt给出了两种度量一个迭代过程收敛快慢的精确标志．笔者证明了当收敛阶p＝1时，R—收敛因子和σ—收敛因子是相等的，从而可以用两种度量标志中的任何一种进行度量．     

细胞自噬与肝病

细胞自噬是真核细胞在长期进化过程中形成的一种自我保护机制,它在清除细胞内蛋白质聚集体、维持细胞内稳态中发挥着重要的作用.近年来研究表明,细胞自噬与各种肝病的病理发生密切相关,本文简要综述该方面的研究进展.     

包装工程与流体力学的一些关系(上)

从学术视角研究包装工程与流体力学的一些关系 .阐述了包装工程中的流体力学现象与包装阻隔模型 ;根据流体力学的相关原理、公式 ,分别论述了液体包装容器底部受力、气体包装中的溢散规律、物品包装中介质扩散的机理与包装防潮原理 .已有的研究提示 ,流体力学是包装防护理论与技术的基础学科之一     

Relationship between cholecystolithiasis and polypoid gallbladder

OBJECTIVE: To study the relationship between cholecystolithiasis and polypoid gallbladder (PLG), 260 patients with polypoid gallbladder were investigated. The patients were divided into 2 groups: group A (PLG combined with cholecystolithiasis) and group B (without cholecystolithiasis). The clinical pathological characteristics were analyzed. The intestinal epithelium metaplasia and atypical hyperplasia of the gallbladder mucosa were observed under light microscope. RESULTS: Intestinal epithelium metaplasia and atypical hyperplasia of gallbladder mucosa were found in 47 of the 260 cases. The pathological lesions included 16 gallbladder carcinoma, 11 adenomatosis polyp, 5 myoadenoma, 7 cholesterol polyp, 4 inflammatory polyp and 4 adenomatosis hyperplasia, which occurred in 26 and 21 patients in group A and group B, i.e. 44.0% and 10.3% respectively. The difference between group A and group B was statistically significant (P<0.01). CONCLUSION: Cholecystolithiasis and the succeeding inflammatory reaction is a risk-factor for the polypoid gallbladder to develop tumour.