Damage assessment and preservation of suspending system of Yongle-Big-Bell

The Yongle-Big-Bell is an exquisite heritage of ancient China and has more than 600 years history. The long history renders the suspending wooden rack serious damage. Therefore, the security is of our great concern. In order to know if the wooden rack is safe or not for the conventional striking in the festival service, a systemic research work has been done. At first the existing deformation and response to the strike of the beetle were measured, and then calculations using method of material mechanics and finite element analysis were conducted. Based on the results of our research, some concluding remarks and suggestion were given: The Yongle-Big-Bell can be struck regularly without urgent danger of collapse. In view of the existence of serious rotten damage, the repair and protection of wooden rack are pressing.

FLOW-PIPE-SEEPAGE COUPLING ANALYSIS OF SPANNING INITIATION OF A PARTIALLY-EMBEDDED PIPELINE

The initiation of pipeline spanning involves the coupling between the flow over the pipeline and the seepage-flow in the soil underneath the pipeline. The pipeline spanning initiation is experimentally observed and discussed in this article. It is qualitatively indicated that the pressure-drop induced soil seepage failure is the predominant cause for pipeline spanning initiation. A flow-pipe-seepage sequential coupling Finite Element Method (FEM) model is proposed to simulate the coupling between the water flow-field and the soil seepage-field. A critical hydraulic gradient is obtained for oblique seepage failure of the sand in the direction tangent to the pipe. Parametric study is performed to investigate the effects of inflow velocity, pipe embedment on the pressure-drop, and the effects of soil internal friction angle and pipe embedment-to-diameter ratio on the critical flow velocity for pipeline spanning initiation. It is indicated that the dimensionless critical flow velocity changes approximately linearly with the soil internal friction angle for the submarine pipeline partially-embedded in a sandy seabed.

Faddeev-Jackiw canonical path integral quantization for a general scenario, its proper vertices and generating functionals

We generalize the Faddeev-Jackiw canonical path integral quantization for the scenario of a Jacobian with J=1 to that for the general scenario of non-unit Jacobian, give the representation of the quantum transition amplitude with symplectic variables and obtain the generating functionals of the Green function and connected Green function. We deduce the unified expression of the symplectic field variable functions in terms of the Green function or the connected Green function with external sources. Furthermore, we generally get generating functionals of the general proper vertices of any n-points cases under the conditions of considering and not considering Grassmann variables, respectively; they are regular and are the simplest forms relative to the usual field theory.

HIRFL-CSR高压静电偏转板放电机理的研究

高压静电偏转板是HIRFL-CSR各级加速器注入引出系统的关键器件，对HIRFL-CSR的运行效率起着重要的作用。本文首先对HIRFL-CSR的几块静电偏转板做了一个简单的介绍，然后通过阅读有关资料，在得到一系列可靠数据的基础上，对静电偏转板的放电机理和优化措施进行了归纳和探讨。 本文重点对SFC引出偏转板的高压放电机理和优化进行了深入的研究。利用CST软件进行的电磁场计算表明：在电场和磁场的共同作用下，盖板损伤的发生部位与实际运行中的打火痕迹完全符合。依据相关理论和计算分析，得到了SFC引出偏转板的放电机理。该放电机理可以很合理的解释各实验现象，并将为SFC引出偏转板的改进提供明确的理论依据。 借鉴前人的经验，本文对SFC引出偏转板的改进进行了研究，这包括电场的优化、偏转板各部分的材料选择和表面处理以及盖板结构的改进。依据相关研究和计算分析，这些改进方案的实施可有效地提高SFC引出偏转板的耐压性能

DG指数在定量多样性时的缺陷及其内涵解析

生物多样性通常使用物种丰富度、Simpson指数、Shannon-Wiener多样性指数等来进行度量,但是在土壤动物群落研究中,由于使用了粗水平的分类方法,因此即使生境变化很大,这些多样性指数在评估群落多样性变化时仍然是不适当的。为了克服这种限制,廖崇惠(1990,2009)提出用DG指数来代替这些标准的多样性指数,并在土壤动物生态学领域得到了广泛应用。然而笔者分析发现DG指数与Pielou均匀度指数呈显著的负相关关系(r=–0.534,P=0.000),即,高的均匀度反而有低的多样性。另外,DG指数与类群数(r=0.648,P=0.000)和类群密度(r=0.487,P=0.000)呈明显的正相关,类群数的下降可以通过部分类群密度的上升而获得补偿,群落的类群丢失后却可以获得一个不变的甚至更高的多样性值。因此,笔者不支持DG指数用于测度生物多样性,提议使用各类群实际群势与潜在群势比值的平均值来估计群落潜在多度的实现程度。如果继续使用DG指数作为实际生境条件的一个指标,那么与以往不同,DG指数测度的是该生境群落多度增长的一种潜力。

不同产地牛蒡子药学质量和种子质量比较

目的:考查不同产地牛蒡子药学质量和种子质量。方法:使用相关分析、灰色关联分析对不同产地牛蒡子做出质量评价。结果:以千粒重和牛蒡苷为指标,北镇采集的牛蒡子药学质量最佳;以千粒重、饱满度、发芽率为指标,徐州采集的牛蒡子种子质量最佳。结论:牛蒡子作为药材不同产地样品质量差别不大,而牛蒡子作为植物牛蒡的种子质量差别较大,栽培品种质量较好。