地应力观测井中元件标定及应力场计算方法

在地应力长期观测中 ,对井下现场标定观测元件的布设以及计算应力的相对变化是一个困难的问题。针对这个问题 ,提出了在钻孔内布设四个应力测量元件 ,而非传统三个元件的测量方法。在井下其中一个元件大体标定的情况下 ,对其他元件进行了相对精密标定 。

内皮细胞应力反应元件的研究进展

内皮细胞能对力学刺激发生反应 ,流体切应力能直接调节内皮细胞基因的表达。现已发现内皮细胞内受切应力调节的基因有 2 0多种。目前认为其调节机制是通过存在于基因的启动子内并且能够被切应力所诱导的启动基因转录的顺式调控元件——应力反应元件来调节基因的转录。目前已知的应力反应元件至少涉及 4种转录因子的结合位点及 10余种受切应力调控的相关基因。这 4种转录因子分别是 :(1) NF-κB;(2 ) AP- 1;(3) Egr- 1和(4 ) SP1。对应力反应元件的基序及基序结合蛋白的鉴定有待进一步的深入 ,以后还可能有新的应力反应元件被发现。在采用基因疗法来调控血管壁不同区段基因表达这方面已进行了有益的探索 。

组织因子凝血途径与切应力反应元件

组织因子（tissue factor,TF）即凝血因子Ⅲ（coagulation factorⅢ）,细胞表面抗原CD 142（CD 142 antigen）,是凝血因子FⅦ/FⅦa的细胞膜表面受体,具有启动凝血和调控细胞内信号传导的作用.近年来发现组织因子凝血途径切应力反应元件（shear stress responsive element,SSRE）与血栓形成的发生、发展有密切关系.本文就TF切应力反应元件表达调控及其与血栓形成的关系作一综述.

切应力诱导大鼠颈动脉内皮细胞组织因子表达的检测与分析

目的在体研究切应力诱导内皮细胞TF基因表达变化规律及其机制。方法54只SD大鼠随机分为对照组和颈动脉狭窄组,狭窄组有又分为0.5、1、3、6、12 h、1、3、7 d 8个时相点,套扎法建立左颈总动脉狭窄模型,术后不同时相点用原位杂交和免疫组化法检测TF、Egr、Sp-1的mRNA和蛋白,用图像分析系统测定内膜平均灰度,进行统计学分析。结果正常对照组内皮细胞TF、Egr-1、Sp-1的mRNA和蛋白弱表达,狭窄30 m in后,内皮细胞胞浆组织因子基因mRNA转录和蛋白合成升高,与对照组比较均有显著性差异(P<0.05)。内皮细胞胞核和胞浆的Sp-1和Egr-1基因mRNA转录和蛋白合成均有显著性增加(P<0.05),但以Egr-1增加更显著(P<0.05),其变化趋势与组织因子基因mRNA转录、组织因子基因蛋白合成的变化趋势相同。TF mRNA和蛋白6 h达到峰值,Egr-1 mRNA和蛋白3 h达到峰值,Sp-1 mRNA和蛋白1 h达到峰值,与邻近组比较差异显著(P<0.05)。结论切应力是内皮细胞组织因子基因表达上调的触发因素之一,切应力激活TF与转录因子Egr-1和Sp-1介导有关。

基于分数阶导数的冻土蠕变本构模型

冻土的蠕变特性与所受应力水平及蠕变应变有关,在高应力水平下会表现出加速蠕变特性。本文在分数阶的非线性黏壶基础上提出了可以描述加速蠕变特性的应力-应变双控元件。传统Nishihara模型难以描述加速蠕变,通过将Nishihara模型中的黏弹性体替换为分数阶的Abel黏壶,将黏塑性体替换为提出的应力-应变双控元件,得到了冻土的一维蠕变本构模型,并将其推广到三维应力状态。提出的模型对冻土的单轴和三轴蠕变试验数据进行了预测分析,和传统Nishihara模型相比,该模型只增加了一个参数,不仅能够反映冻土在低应力水平下冻土衰减蠕变和稳定蠕变特性,而且还可以较好地反映冻土在高应力水平下加速蠕变规律。说明了该模型对于描述冻土在不同应力条件下不同蠕变状态的适用性。

Research on 1-3 Orthogonal Anisotropic Piezoelectric Composite Material Sensors-

Piezoelectric composite material (PCM) is an important branch of modernsensor and actuator materials with wide applications in smart structures. In this paper, based onpiezoelectric ceramic, composite and experimental mechanics theories, a kind of 1-3 orthogonalanisotropic PCM (OAPCM) sensor is developed, and the sensing principle is analyzed to describesensor behaviors. In order to determine strain and stress on isotropic or orthogonal anisotropiccomponent surface, the relationships between strain and stress are established. The experimentalresearch on 1-3 OAPCM sensor is carried out in uniaxial and biaxial stress states. The results showthat 1-3 OAPCM sensors offer orthotropic properties of piezoelectricity, and sensing equations canbe used for strain or stress measurement with good accuracy.

一族具有直流链电压尖峰抑制的T源逆变器

针对于T源逆变器因漏感导致的直流链电压尖峰问题,通过对T源阻抗网络进行优化并调整各元件的位置,提出低直流链电压尖峰T源逆变器拓扑族。该文对新提出拓扑的工作模态进行详细分析,进而推导出各元件的电压、电流应力。此外,通过与传统T源逆变器在升压比方面进行对比,证明出在相同的直通占空比和耦合电感匝数比情况下,低直流链电压尖峰T源逆变器拥有更好的升压能力。最后,研制一套180 W的低直流链电压尖峰T源逆变器实验装置,实验结果验证了理论分析的正确性及所提拓扑结构在拥有高电压增益的同时能够提高输入电源利用率、抑制直流链电压尖峰的有效性。

抑制脑血栓形成的硫代磷酸酯脱氧寡核苷酸的亲和性研究

目的为抑制脑血栓形成,合成与TF基因启动子区切应力反应元件(SSRE)形成三链DNA的硫代磷酸酯寡核苷酸(TFO)。方法设计TFO序列14条,采用固相亚磷酰胺三酯固相法合成TFO。硫代磷酸酯修饰在TFO的3'末端进行。应用电泳迁移分析(EMSA)观察寡核苷酸和硫代脱氧寡核苷酸的亲和性。结果在设计合成的14条寡核苷酸中,与靶序列能形成三链DNA的TFO只有T21GTa、T14GTa和T15GTa,其Kd值分别为3.6×10-10、1.0×10-9和1.0×10-8(M),经硫代磷酸酯修饰后分别为:2.3×10-9、3.8×10-9和1.5×10-8。结论硫代磷酸酯修饰的T21GTa-ps、T14GTa-ps和T15GTa-ps能够与TF基因启动子SSRE的3个位点形成三链DNA。

用于大气化学实验的傅里叶变换光谱仪的设计(下)

3.2.1结构设计 这种多学科的结构设计需要在结构上和温度上进行耗时数月的有限元分析(多达140000个自由度).大多数有限元分析是通过试验而相关的,为了调整光学、电学、伺服和系统方面的要求,有关人员对光学-机械结构采取了许多折衷措施.ACE-FTS仪器被设计得能够承受发射时的振动负荷和在轨道上的热负荷.图8所示为仪器的结构有限元模型.

Analysis of Differences in Inductance of Ni-Cu-Zn Ferrite Chip Inductors during the Plating Process

Although plating is a necessary process for SMT components, it alters the magnetic characteristics and inductance level of Ni-Cu-Zn ferrite components. The results of this work show that the following three factors in plating affect these components, and the effects are different for Ni- and Sn-plating： （1） Plating layers exert stresses and react with the residual stress of components to change the inductance level, and the effect of the tin layer is greater than that of the nickel one; （2） The plating current induces a magnetic field inside the components directly and indirectly, and this remains as remanence inside the components and reduces the inductance level, and the effect level of Ni-plating is greater than that of Sn-plating; （3） The plating solution corrodes the interface of the termination and ferrite core of the components to release the residual stress, and causes an increase in inductance, and the effect of Sn-plating is greater than that of Ni-plating. In addition, the inductance level is the result of the net effect of these three factors, and if the sintering temperature is increased to change in the type of residual stress, the net effect will be changed.

FEM analysis of vacuum hot bulge forming of Hastelloy C-276 thin-walled cylindrical workpiece

A stress relaxation test has been carried out for Hastelloy C-276 at temperature of 800 ~C and initial stress level of 250 MPa. Based on the experimental stress relaxation curve, the relationship between creep strain rate and stress has been derived. Then, a set of creep constitutive equations has been built and the values of constants arising in the constitutive equations have been determined by fitting the creep strain rate-stress curve. Close agreement between computed results and experimental ones is obtained for stress relaxation data. The creep constitutive equation set has been integrated with the commercial FE （finite element） solver MSC.Marc via the user defined subroutine, CRPLAW, for the vacuum hot bulge forming process modelling of Hastelloy C-276 thin-walled cylindrical workpiece. The temperature field, the radius-direction displacement field and the stress-strain field are calculated and analyzed. Furthermore, the bulging dimension and the final internal diameter of workpiece are predicted and the test results verify the reliability of the finite element method.

The Deformation and Stress Analysis of Na Ba Reservoir Concrete Face Rock-Fill Dam

Based on the APDL （ANSYS Parametric Design Language） and combined with the actual project related to parameters of filling material, imported Duncan-Chang constitutive model which has been widely applied in soil mass and rock-fill in the ANSYS software. With the three-dimensional nonlinear finite element analysis by the mid-point incremental method, what have been computed are the deformation and stress analysis ofNa Ba reservoir CFRD （Concrete Face Rock-fill Dam） in filling period. The calculation results provide practical reference for the dam during construction safety filling stress and deformation analysis and real-time monitoring.

Numerical simulation of cutting process of the slice components cutting machine

By the use of ANSYS/LS-DYNA FEA software,numerical simulation on the cutting process of cutting plates with a reamer was carried out in the paper. The logical improvement was brought forward and the phenomenon of stress concentration was deceased by weighted analysis. The effects of different cut velocities and cutting thickness on life-spans of reamers were investigated, and the cutting parameters were optimized to satisfy the cutting precision and cutting efficiency. The study will provide a guide for the practical production.

The Topic of Contact Zone Problems in the Shaft and Hole Joint, Taking into Account Component Form Errors

In assemblies constructed from components manufactured with radial deviations, cross-section deviations and deviations being combination of both, there occur variable values of local stresses and displacements. Both the types of shape deviations and their values need to be taken into account in the designing process and play an important role during machine operation. They have a crucial effect on the value and scatter of maximum reduced von Mises stresses and contact stresses. Axisymmetric joints were examined, in which shafts in selected shape variants and in variable angular positions were associated with a non-deformable hole. The aspects of contact zone problems are presented using the example of numerical simulation of contact between an elliptical saddle-shaped shaft placed in a rigid, non-deformable hole in different angular positions. Occurrence of both variable relative stresses and contact stresses as well as shaft＇s axial shift and rotary movement resistance were demonstrated.

Dynamic responses research of offshore wind turbine tripod foundation and upper structure

In order to obtain the performance of the offshore wind turbine tripod foundation, a tripod foundation model was built by ANSYS. The static analysis, modal analysis and the transient dynamic analysis were run. Different parameters such as displacement, velocity, acceleration, stress were obtained and by analyzing these data, it is reasonable to draw a conclusion that the tripod foundation has a good performance used on the offshore wind turbine.

THE EFFECT OF COUPLED FEEDBACK ON NOISE FILTERING IN SIGNAL TRANSDUCTION NETWORKS

Many interacting biomolecular components in cells form different positive or negative feedback loops. When biological signals transduce through cascades consisting of various loops they will be affected or even distorted. Especially, how to process various signals buried in various intrinsic and extrinsic noises is an important issue. This paper analyzes how the response time influences noise filtering ability and how to enhance the ability by coupling different feedback loops. A parameter to measure the response time of the signal transduction, i.e., τ0.9, and its relationship between the response time and noise filtering will be discussed. The authors show clearly that the longer the response time is, the better the ability to filter noises will be. Therefore, to enhance the ability to filter noises, the authors can prolong the response time by coupling different positive or negative feedback loops. The results provide a possible approach to enhance the ability to filter noises in larger biomolecular networks.