查询词典 crack up under the strain of poverty

The main research tasks and results are as follows:(1) Through comparing the stress intensity factor of compact tension specimen calculated by finite element software with the theoretical value, the feasibility of calculating fracture parameters of crack tip in ABAQUS software was verified.(2) The relationship between the elastic modulus of the material and research scale was studied based on deriving the cohesive stress theory and other relevant theories. And the elastic modulus of the material on meso-scale was determined.(3) Global model and sub-model of the finite element were built in th...e macro-scale, and stress-strain field nearby the crack tip was analyzed, and the results show that the detailed stress-strain in the crack tip could be obtained by using the sub-model technique.(4) In meso-scale, the crack growth model was also established by assuming the crack propagating along the grain boundary, and the detailed stress-strain field in the crack tip was obtained.(5) The effect of crack length on Von Mises stress, and maximum principal stress and strain was analyzed in meso-scale when equivalent KI equals 30MPa.m1/2. And the results show that except for crack tip area, the stress-strain distribution in whole specimen is not affected.

主要完成研究内容和取得成果如下：(1)利用有限元软件计算出紧凑拉伸试样的裂纹尖端应力强度因子KI值，其结果与理论值一致，从而验证了利用ABAQUS计算裂纹尖端相关断裂参量的可行性；(2)在研究内聚应力等相关理论的基础上，推导出了研究尺度与材料弹性模量的近似关系，并确定了介观尺度上的弹性模量；(3)在宏观尺度上建立了全局有限元计算模型和子模型，得到了裂纹尖端应力应变场分布，结果表明利用子模型技术获得比较准确的裂纹尖端应力应变场分布是可行的；(4)在介观尺度上利用平均晶粒尺度的方式建立了裂纹沿晶扩展模型，得到了裂纹尖端断裂过程区的微观应力应变场；(5)当应力强度因子为30MPa.m1/2时，分析了介观尺度上在裂纹沿晶扩展过程中裂纹长度对Mises应力、最大主应力和应变的影响，结果表明，裂纹扩展长度对试样整体应力应变分布影响不大，而对裂纹尖端区域有较大影响；(6)介。。。

In the case of granite, observation results indicate that the extending routes of active cracks are mainly intercrystalline, transcrystalline, inter-transcrystalline, and intracrystalline. When the strain rate is low, the long intercrystalline cracks are prevailing, and with increasing of the strain rate, the short transcrystalline and intracrystalline cracks gradually increase. The statistic results show that the active crack density increases with increasing of the strain rate, and the mean length of active cracks diminishes with increasing of the strain rate, that is, the induced damage in comminuted product increases with increasing of the strain rate. For the first time this dissertation integrates macroscopic results of comminution with active crack growth under impact loading. It elucidates why the dynamic comminution strength of mineral beds increases with increasing of the strain rate through the active crack extending, and analyzes the influence of structure and constitution of minerals on their damage under impact stress. It is authenticated that both the size distribution and the damage population of comminuted product can be characterized by the fractal.

为分析料层颗粒在冲击下的细观损伤效果，采用德国生产的ASM68K半自动图象分析仪对粉碎生成物中的损伤情形进行了观测，以花岗岩为例，观测结果表明花岗岩颗粒在冲击应力下的活化裂纹扩展路径主要表现为沿晶、穿晶、沿穿晶和晶内等形式，在低应变速率下，活化裂纹以沿晶裂纹较多，随着应变速率的提高，其它裂纹形式大量繁衍，统计结果表明活化裂纹密度随着应变速率的增大而增大，活化裂纹的平均长度随着应变速率的增大而减小，综合表现为颗粒的细观损伤程度随着应变速率的增大而增大；首次将应力作用下的活化裂纹演化特征与粉碎的宏观效果相联系，并就料层动态粉碎强度随应变速率增大而提高的现象从裂纹演化特征的角度进行了解释；分析了矿岩构造结构特性对损伤产生和分布的影响。

Now the facing new problems are a relative worsen of the living conditions among the poverty population, enlarging difficultness for the poverty population to add income, increasing the cost of the anti-poverty, disjointedness between the government anti-poverty policy and its goal, investment absence and illogic structure in the anti-poverty capital, lack of inspirit mechanism of the poverty population in the poverty areas, the conflict among the anti-poverty.

目前面临的新问题是：贫困人口的生活状况相对恶化，贫困人口增收的难度加大，贫困人口的脱贫成本逐年增加，政府的扶贫政策与扶贫目标相左甚至背离，扶贫资金的投入力度不够，且结构不合理，对贫困地区和贫困人口缺乏激励机制，扶贫工作的许多矛盾相互交织。

Firstly, we collected and sorted out the GPS data, established the uniform velocity field for the Chinese mainland and the surrounding regions, and the horizontal deformation field relative to the Eurasia plate; Secondly, we established a motion model for the entire rotation and homogeneous strain of the first and second level blocks in Chinese mainland, analyzed the motion pattern and strain behavior of active blocks in Chinese mainland, as well as the motion pattern of principal fault zones in Chinese mainland; Thirdly, considering the heterogeneity of strain distribution inside a block and supposing that the strain tensor inside the block is the linear function of location, we derived and established an equation for the entire rotation and linear strain of block and a motion model for the entire rotation and linear strain of principal blocks in Chinese mainland; We also calculated the principal strain field and the maximum shear strain field in Chinese mainland and the surrounding regions, analyzed the basic characteristics of strain field in Chinese mainland, as well as the relationship between the spatial distribution of strain field and large tectonic zones; Finally, we established the 2-D geotectonic model and digital model for Chinese mainland and the surrounding regions, calculated the stress field in Chinese mainland and the surrounding regions, and analyzed the basic features of stress field in Chinese mainland and the principal driving force for the motion and deformation in Chinese mainland.

收集整理了已有GPS资料，建立了中国大陆及周边地区统一的速度场以及相对欧亚板块的水平形变场；建立了中国大陆一、二级地块整体旋转与均匀应变的运动模型；分析了中国大陆活动地块的运动状态，应变状态，以及中国大陆主要断裂带的运动状态；考虑到一个块体内部应变张量空间分布的非均匀性，假设块体内部的应变张量是位置的线性函数，推导建立了块体整体旋转与线性应变方程，建立了中国大陆主要地块整体旋转与线性应变的运动模型；计算了中国大陆及周边地区的主应变场与最大剪应变场，分析了中国大陆应变场的基本特征，以及应变场的空间分布与大型构造带的关系；建立了中国大陆及周边地区二维的地质构造模型和数值模型，计算了中国大陆及周边地区的应力场，分析了中国大陆应力场的基本特征以及中国大陆运动、形变的主要驱动力。

Theobserved strain is 10~2 times as local point strain at the same observed stress.This indicates that macroscopical symmetrical rock is quasi-brittle materialwith microcosmic heterogeneousness and its macroscopical mechanicalbehavior is the results of reciprocity and magnification between microcosmiccharacteristic, not simple sum.(4) The degree of irregularity of strain increases with the number of cycle.But degree of irregularity of transverse strain fluctuates larger at the samecycle. Moreover degree of irregularity of transverse strain is larger than that ofaxial strain. This shows that deformation and failure of rock is process ofevolvement of small crack. Small crack evolves from even and out-of-orderstatus to heterogeneous and ordinal status.(5) Ultrasonic speed decreases with the number of cycle. The decreasecourse is such: Firstly, ultrasonic speed fluctuates in a steady scope in somecycles; And then ultrasonic speed quickly decreases to a certain more smallvalue; Afterwards in succedent cycles, ultrasonic speed fluctuates about thevalue. That is to say, ultrasonic speed fluctuates and decreases at intervals ofcycles. In deformation process of rock, quantitative change and qualitativechange of its small crack evolvement carry through crosswise.(6) Strength and modulus of rock decrease with exponential function asscale of specimens increases.

同一表观应力下，局部点应变与表观应变相差可达2个数量级，表明宏观上均匀的岩石是具有细观特征的准脆性材料，其宏观力学行为是细观特征相互作用、放大的综合结果，而不是简单的叠加；(4)岩样轴向应变不均匀程度和横向应变不均匀程度随循环次数的增加渐进增大，但是在同一个循环内，横向应变离散系数随应力的变化波动较大，且同一循环级别下，横向应变不均匀程度大于轴向应变不均匀程度，表明岩石内部微裂纹的演化是岩石变形破坏的本质特征，这一演化表现为微裂纹从均匀无序分布逐渐向非均匀有序发展；(5)随循环次数的增加，所有岩样内部超声波速会出现衰减，衰减过程表现为在某几次循环内超声波速在某一相对范围内波动，然后急剧减小到某一较小值，在随后的循环内，超声波速又会保持在这一较小值附近波动，即超声波速表现为波动和急剧减小间隔形式衰减，表明从宏观看来平稳的岩石变形过程，内部结构演化过程(微裂纹发展及其相互作用)却表现为均匀量变和突发质变不断交叉进行的现象；(6)岩石强度和弹性模量随尺度增大呈指数函数规律减小。

It is clarified for the first time that the thermal fatigue failure of solder joint is actually a creep strain low cycle fatigue failure, and a physical model for creep fatigue crack propagation has been proposed. It was pointed out that creep strain increases in the high stress area ahead of the tip of thermal fatigue crack, results on one hand that the slide of crack tip increase, inactivation more serious and crack close length increases, the other hand, that intergranular crack exists, whose direction will affect the fatigue crack propagating.

本文首次阐明了焊点的热循环失效本质上是以焊点内循环蠕变为主要应变的低周疲劳失效，并在此基础上提出了蠕变疲劳裂纹扩展的物理模型，指出热循环裂纹前端的高应力区内，蠕变加剧，使裂纹前端滑移增加，裂纹钝化加剧，导致随后的裂纹闭合扩展长度增加；同时蠕变也使裂纹前端的高应力区出现晶间裂纹，蠕变沿晶裂纹对主裂纹扩展的影响取决于沿晶裂纹的连接方向。

Crack propagation problems under the influence of the edges of the crack subjected to homogenous loads, the origin of the coordinates subjected to concentrated increasing loads, the central zone of the edges of the crack subjected to homogenous loads, the certain point of the edges of the crack subjected to moving unit step loads, the origin of the coordinates subjected to moving increasing loads Px m, the edges of the crack subjected to instantaneous impulse loads, the edges of the crack subjected to moving concentrated variable loads, the origin of the coordinates subjected to point loads, the edges of the crack subjected to a constant moving concentrated loads and the origin of the coordinates subjected to instantaneously moving impulse loads are studied respectively, and the analytical solutions of dislocation distribution function have been obtained.

同时对裂纹面受均布载荷、坐标原点受集中增加载荷、裂纹面中心区受均布载荷、裂纹面上某点受运动阶跃载荷、坐标原点受运动增加载荷Px m、坐标原点受瞬时冲击载荷、裂纹面受运动集中变载荷、坐标原点受集中载荷、裂纹面受常数运动集中载荷、坐标原点受瞬时运动冲击载荷作用下的裂纹扩展问题分别进行了研究，获得了位错分布函数的解析解。

The crack that see much of most in several residence is that a layer maneuver a wall to hand over to connect place to have the stairs form the crack creation;Hand over to connect place or beam bottom and wall body to have the level crack the creation in the house noodles and the wall body;There is Shu under the first floor window sill toward the crack creation, the window sill of each floor two wall window way outside the layer four Cape existence inclined crack;Small scaled and hollow carve in the reinforced concrete pillar and the Mao a piece of fill a wall of mutually knot existence the Shu is to the crack;It is carve a piece periphery a creation crack.

随着国家保护耕地措施的实施，粘土砖的使用逐步得到控制，砼小型空心砌块在住宅工程中开始得到越来越多的应用期刊文章分类查询，尽在期刊图书馆在多层住宅中最常看到的裂缝是顶层纵横墙交接处有阶梯形裂缝产生；在屋面与墙体交接处或梁底与墙体间有水平裂缝产生；在底层窗台下有竖向裂缝产生，各个楼层的窗台两角和顶层外墙窗口四角处有斜裂缝存在；在钢筋混凝土柱和砼小型空心砌块填充墙的相结处有竖向裂缝存在；在砌块周边产生裂缝。

The crack that see much of most in several residence is that a layer maneuver a wall to hand over to connect place to have the stairs form the crack creation;Hand over to connect place or beam bottom and wall body to have the level crack the creation in the house noodles and the wall body;There is Shu under the first floor window sill toward the crack creation, the window sill of each floor two wall window way outside the layer four Cape existence inclined crack;Small scaled and hollow carve in the reinforced concrete pillar and the Mao a piece of fill a wall of mutually knot existence the Shu is to the crack;It is carve a piece periphery a creation crack.

随着国家保护耕地措施的实施，粘土砖的使用逐步得到控制，砼小型空心砌块在住宅工程中开始得到越来越多的应用在多层住宅中最常看到的裂缝是顶层纵横墙交接处有阶梯形裂缝产生；在屋面与墙体交接处或梁底与墙体间有水平裂缝产生；在底层窗台下有竖向裂缝产生，各个楼层的窗台两角和顶层外墙窗口四角处有斜裂缝存在；在钢筋混凝土柱和砼小型空心砌块填充墙的相结处有竖向裂缝存在；在砌块周边产生裂缝。

Based on the qualitative interpretation,the effect of transition segment of a stress-strain curve has been emphasized;phenomenon relating to strain rate effect have been adequately discussed,such as the stress-strain curve of a given strain rate, the increase of strain rate sensitivity of a metal with temperature,the decomposition of strain rate effect and strain hardening and multi-step loading tests.The analyses agree with the existing experimental results and update the knowledge on strain rate effect.

对材料应变率敏感性随温度变化的现象进行了分析，所得结论与现有试验结果相符；对晶体材料在恒应变率加载下的应力应变曲线进行了分析，明确提出了应力应变曲线中受应变率直接影响部分—过渡段的概念；结合位错运动分析，对恒应变率加载下晶体材料的应力应变曲线进行了解释，深化了对应变率效应的认识；提出了应变率效应与应变硬化效应可分别研究的观点，完善了对应变率效应细观机理的认识。

The United Kingdom has pledged to provide technical assistance to the peacekeeping effort in Darfur, including airlifting supplies and equipment to assist the African peacekeepers.

英国承诺为达佛的維和努力提供技术帮助，包括提供非洲的維和部队空运补給和裝备。

Results: The level of ET-1mRNA in placental villus was significantly higher in pre-eclamptic women than that in control group.

结果：妊高征组患者胎盘绒毛组织ET-1 mRNA的表达较正常妊娠组明显增高。