朱红膏对皮肤破损模型大鼠量毒关系研究

目的:探讨朱红膏对破损皮肤模型大鼠的量毒关系。方法:随机将大鼠分成对照组、朱红膏低、中、高剂量(19.04、38.08、76.16mg生药/kg)4组。分别于连续给药4周和停药4周后,测定汞含量、β-N-乙酰胺基葡萄糖苷酶(NAG)、碘[125I]β2-微球蛋白(BMG)、丙氨酸转移酶(ALT)、天门冬氨酸氨基转移酶(AST)、肌酐(Scr)、尿素氮(BUN)、血常规、相关凝血指标、脏器系数,同时进行肾脏组织形态学观察。结果:连续给药4周,朱红膏低、中、高剂量组血、尿汞和肾汞含量与对照组比较显著性升高(P<0.01),且存在量毒关系。停药4周,朱红膏低、中、高剂量组血、尿汞含量均恢复正常,肾汞含量仍显著性升高(P<0.01)。高剂量组大鼠肾脏系数及尿NAG显著性升高(P<0.01)。停药4周,不同剂量组与对照组比较没有统计学差异。结论:对破损皮肤模型大鼠长期大剂量使用朱红膏会出现汞蓄积,可能造成肾组织损伤。

地震破坏管线漏损分析模型对比研究

城市供水管网震后水力功能分析是评价管网震后服务能力的重要手段,针对震后漏损管网水力分析中的破坏管线出流量及其拓扑结构进行模型对比研究。通过管线破坏处的水流形态分析,得到了管网渗漏点和断开点的流出量表达式;利用局部水头损失与沿程水头损失间的等损失转化关系,建立了渗漏点与断开点出流模型的转化关系;比较分析了不同漏损出流模型的差异及其在震后管网水力计算中的适用性。分析和示例管网计算结果表明,渗漏点和断开点的水流量应分别由孔口出流处的局部水头损失和断开管段的沿程水头损失计算。

朱红膏对破损皮肤模型大鼠汞蓄积及肾组织形态的影响

目的:通过对破损皮肤模型大鼠连续给予朱红膏4周和停药4周各相关指标的检测,探讨其对汞蓄积和肾组织形态的影响,为临床安全用药提供科学依据。方法:将大鼠随机分成4组:破损皮肤对照组、朱红膏低、中、高剂量组。于连续给药4周和停药4周后,分别测定尿汞、血汞、肾汞、β-N-乙酰氨基葡萄糖苷酶(NAG)、β2-微球蛋白(β2-MG)、血清尿素氮(BUN)、肌酐(SCr)、尿蛋白(PRO)和尿液pH,计算肾脏系数,进行肾脏组织形态学观察。结果:连续给药4周,3个剂量组大鼠尿汞、血汞和肾汞含量与对照组比较显著升高(P<0.01),且存在量毒关系。停药4周,3个剂量组大鼠尿汞和血汞含量均恢复正常,肾汞含量仍明显升高(P<0.01)。高剂量组大鼠NAG显著升高。停药4周,不同剂量组与对照组比较没有差异。结论:对破损皮肤大鼠长期大剂量使用朱红膏会出现汞蓄积,有可能造成肾组织损伤,临床使用朱红膏应积极监测患者体内的汞含量和肾功能指标。

Numerical investigation of effect of eccentric decoupled charge structure on blasting-induced rock damage

Eccentric decoupling blasting is commonly used in underground excavation.Determination of perimeter hole parameters(such as the blasthole diameter,spacing,and burden)based on an eccentric charge structure is vital for achieving an excellent smooth blasting effect.In this paper,the Riedel-Hiermaier-Thoma(RHT)model was employed to study rock mass damage under smooth blasting.Firstly,the parameters of the RHT model were calibrated by using the existing SHPB experiment,which were then verified by the existing blasting experiment results.Secondly,the influence of different charge structures on the blasting effect was investigated using the RHT model.The simulation results indicated that eccentric charge blasting has an obvious pressure eccentricity effect.Finally,to improve the blasting effect,the smooth blasting parameters were optimized based on an eccentric charge structure.The overbreak and underbreak phenomena were effectively controlled,and a good blasting effect was achieved with the optimized blasting parameters.

Dynamic failure mode and energy-based identification method for a counter-bedding rock slope with weak intercalated layers

The dynamic failure mode and energybased identification method for a counter-bedding rock slope with weak intercalated layers are discussed in this paper using large scale shaking table test and the Hilbert-Huang Transform(HHT) marginal spectrum.The results show that variations in the peak values of marginal spectra can clearly indicate the process of dynamic damage development inside the model slope.The identification results of marginal spectra closely coincide with the monitoring results of slope face displacement in the test.When subjected to the earthquake excitation with 0.1 g and 0.2 g amplitudes,no seismic damage is observed in the model slope,while the peak values of marginal spectra increase linearly with increasing slope height.In the case of 0.3 g seismic excitation,dynamic damage occurs near the slope crest and some rock blocks fall off the slope crest.When the seismic excitation reaches 0.4 g,the dynamic damage inside the model slope extends to the part with relative height of 0.295-0.6,and minor horizontal cracks occur in the middle part of the model slope.When the seismic excitation reaches 0.6 g,the damage further extends to the slope toe,and the damage inside the model slope extends to the part with relative height below 0.295,and the upper part(near the relative height of 0.8) slides outwards.Longitudinal fissures appear in the slope face,which connect with horizontal cracks,the weak intercalated layers at middle slope height are extruded out and the slope crest breaks up.The marginal spectrum identification results demonstrate that the dynamic damage near the slope face is minor as compared with that inside the model slope.The dynamic failure mode of counter-bedding rock slope with weak intercalated layers is extrusion and sliding at the middle rock strata.The research results of this paper are meaningful for the further understanding of the dynamic failure mode of counter-bedding rock slope with weak intercalated layers.

Numerical simulations on rock damage and fragmentation by blasting

a damage constitutive model comprising two dynamite sticks is established and handled with the transient dynamics finite element computer program PRONTO-3D to study rock damage and fragmentation during blasting. Simulation tests find that tensile stress by detonation gives rise to tensile bulk strain and consequently damage in the material. Maximum bulk strain is observed in simultaneous detonations of the two dynamite sticks. It is demonstrated that the proposed method is applicable to studying the process of rock damage by blasting as well as its affecting factors.

An Improved Damage Identification Method Based on Mode Information

This paper presents a new algorithm to predict locations and severities of damage in structures by changing modal parameters. An existing algorithm of damage detection is reviewed and the new algorithm is formulated to improve the accuracy of damage locating and severity estimation by eliminating the erratic assumptions and limits in the existing algorithm. The damage prediction accuracy is numerically assessed for each algorithm when applied to a two-dimensional frame structure for which pre-damage and post-damage modal parameters are available for only a few modes of vibration. The analysis results illustrate the improved accuracy of the new algorithm when compared to the existing algorithm.

三维模型导入差异问题解决方法

简述了实体模型概念。介绍了实体模型的作用，分析了工程工作中经常遇到的非Creo三维模型导入Creo出现的差异以及导致破损的原因，整理并归纳了该导入差异的解决办法，为工程工作中的产品发放和分析设计提供解决方案。

A constitutive model for granular materials considering grain breakage

A particle breakage has a significant impact on the mechanical behavior of granular materials. In this paper, we present an elasto-plastic model with two yield surfaces to which the influence of particle breakage has been introduced. The main feature of this model is to incorporate the change in the critical state line (CSL) consequent to the grain breakage induced by isotropic and deviatoric stresses during loading. For this purpose we propose a breakage function which connects the evolution of the CSL to the energy consumed. Results from earlier studies on drained and undrained compression and extension triaxial tests were used to calibrate and validate the model. Comparison between earlier results and our simulations indicates that the model can reproduce with good accuracy the mechanical behavior of crushable granular materials and predict the evolution of the grain size distribution during loading.

Damage and progressive failure of concrete structures using non-local peridynamic modeling

Peridynamics (PD), a recently developed theory of solid mechanics, which employs a non-local model of force interaction and makes use of integral formulation rather than the spatial partial differential equations used in the classical continuum mechanics theory, has shown effectiveness and promise in solving discontinuous problems at both macro and micro scales. In this paper, the peridynamics theory is used to analyze damage and progressive failure of concrete structures. A non-local peridynamic model for a rectangular concrete plate is developed, and a central pairwise force function is introduced to describe the interior interactions between particles within some definite distance. Damage initiation, evolution and crack propagation in the concrete model subject to in-plane uni-axial tension, in-plane uni-axial compression and out-of-plane impact load are investigated respectively. The numerical results show that discontinuities appear and grow spontaneously as part of the solution to the peridynamic equations of motion, and no special failure criteria or re-meshing techniques are required, which proves the potential of peridynamic modeling as a promising technique for analyzing the progressive failure of concrete materials and structures.

Three dimensional efficient meshfree simulation of large deformation failure evolution in soil medium

An efficient Galerkin meshfree formulation for three dimensional simulation of large deformation failure evolution in soils is presented. This formulation utilizes the stabilized conforming nodal integration, where for the purpose of stability and efficiency a Lagrangian smoothing strain at nodal point is constructed and thereafter the internal energy is evaluated nodally. This formulation ensures the linear exactness, efficiency and spatial stability in a unified manner and it makes the conventional Galerkin meshfree method affordable for three dimensional simulation. The three dimensional implementation of stabilized conforming nodal integration is discussed in details. To model the failure evolution in soil medium a coupled elasto-plastic damage model is used and an objective stress integration algorithm in combination of elasto-damage predictor and plastic corrector method is employed for stress update. Two typical numerical examples are shown to demonstrate the effectiveness of the present method for modeling large deformation soil failure.