利用应力莫尔圆解析成矿热液对岩石的机械破裂作用

在成矿作用中,成矿热液对岩石的破坏作用分为以机械破裂为主的物理作用和以腐蚀交代为主的化学作用。成矿热液对岩石的机械破裂作用与矿床的形成联系非常紧密。当成矿热液的压力与岩石的构造应力满足一定条件时,岩石就会发生破裂;从而显著提高岩石的渗透率,提供流体运移通道并且形成成矿场所。因此成矿热液对岩石的机械破坏作用是形成容矿断层的重要因素。用应力莫尔圆解析了这一过程,并以新疆哈密红石铜矿论证了这一过程。

几种快速提取新生隐球菌DNA的方法

目的 探讨几种快速提取新生隐球菌DNA方法的效果。方法 分别用玻璃珠机械破裂法、酶消化法、高渗剂破裂法及三法联合法提取有荚膜的新生隐球菌B 3 50 1野生株DNA ,用联合法提取 5种血清型新生隐球菌标准株的DNA ,用紫外分光光度计检测提取DNA的浓度和纯度。结果 4种方法抽提 2ml新生隐球菌培养液 (菌体数约为 1×10 8个 /ml) ,可获得DNA的量约是 64～ 2 0 3 μg。酶消化法、高渗剂破裂法及三法联合法抽提的DNA ,其OD2 60 /OD2 80比值均小于 1.8。结论 除玻璃珠机械破裂法外 ,酶消化法、高渗剂破裂法 ,以及三法联合法均可用于快速抽提新生隐球菌的DNA。

玻璃破碎原因简要分析

通过简要地分析玻璃本身的特性以及玻璃的缺口理论、抗弯曲强度和温差之间的关系,阐述了普通玻璃及钢化玻璃破碎的原因大致分为热破裂和机械破裂,而钢化玻璃作为特例,分析了热浸测试对减少钢化玻璃因NiS自爆的改善作用,最后用图例的方式显示不同的玻璃破裂形式,希望对玻璃的破碎原因的分析提供一定的帮助。

Mechanical properties of frozen rock mass with two diagonal intersected fractures

Based on previous research results, this paper investigated the influence of fracture morphology on mechanical properties and failure modes of rock mass with two diagonal intersected fractures. This study carried out a series of triaxial compression tests on rock-like specimens with two crossed fractures under negative temperature, concluded the following conclusions. The strength and failure modes of rock mass are significantly influenced by the dips of two crossed fractures. The strength of rock mass with two frac- tures cannot simply be estimated using the method that was developed for the rock mass with a single fracture. When the intersecting angle is less than 30~, the failure plane initiates at the tip of ＂artificial rup- tures＂ and extends to the upper and lower ends of the specimen. In case of a higher dip and intersecting angle ranging from 30° to 60°, the failure plane propagates along one of these two fractures. The mechan- lca! parameters of rock mass are not only related to the trace length, but also depend on the trace !ength ratio. One could roughly calculate the strength parameters using the approximation proposed in.this paper..For the rock mass with a trace length ratio 〈0.3 （short trace length/long trace length）, the failure mode is dependent on the fracture with a longer trace length. When the trace length becomes significant and the trace length ratio approximates to 1, the failure plane propagates along two fractures, where an X-shaped.failure pattern is presented： For the rock mass with moderate frac!ures and a trace length ratio of approxlmately 1, the failure mode Is.Independent on fractures, which is simllar to .the damage pattern of intact rock. The strength, and elastic .modulus of rock mass decrease with the increase of spacing between fractures, whl!e Polsson＇s ratio is Independent on the spacing. The failure mode can be deter- mined by the area. of triangle created by two fractures. Damage occurs at the smaller triangle area first, and propagates with the two sides of the larger triangle.

AN EXPERIMENTAL STUDY ON DYNAMIC FRACTURE SPEED

This paper deals with an experimental study on dynamic fracture speed of three point bending specimen and cylindrical specimen made of epoxy resin by means of silver conductive painting grid. According to the test results ,the relations between fracture load ,fracture speed and loading speed are discussed and the features of final fracture surfaces are analysed in detail.

Elasticity soltion of rupture model of shallow earthquake

Based on the theory of elastic mechanics,and using the typical rupture model of shallow earthquake,the authors considered the shallow earthquake as a plane mechanical problem,which was constructed the corresponding mechanical model.By the stress components' formulas of the semi-infinite model acted by the finite even shearing force,the main stress is deduced.It is clear that the sector on the right of the center section is squeezed zone,where the maximum principal stress points at the "source of stress",and that on the left is tensile zone,where the minimum principal stress points to the "source of stress".

Comparative study of mechanical-electrical-thermal responses of pouch, cylindrical, and prismatic lithium-ion cells under mechanical abuse

In the study, mechanical abuse tests mainly in the form of indentation were performed on the cylindrical cell, pouch cell, and prismatic cell. The mechanical force-displacement response, open circuit voltage(OCV), and temperature distribution were recorded and compared. In spherical head indentation tests of the pouch and prismatic cell and lateral indentation of the cylindrical cell, the peak force is strongly correlated with OCV drop and local temperature increase. However, in flat-end cylinder indentation tests, the internal mechanical damage is progressively developed, and the OCV drop and the temperature increase occur before the peak force. The fracture surfaces of the post-mortem samples were examined to investigate the correlation between fracture patterns and internal short circuit(ISC) behaviors(OCVand temperature distribution). Two distinct fracture patterns were observed that the in-plane fracture induced by biaxial stretching and inter-layers' fracture induced by shearing. A strong correlation is observed between the number of shear fractures and OCV drop. An increase in the number of inter-layers' fractures increases the rate of OCV drop. Additionally, the fracture patterns influence the ISC area and location,thereby affecting the heat generation and conduction as well as the temperature distribution.