断裂的

Three are three major actions that Mn effects fracture behavior in the alloy at room temperature, as follow: One is that Mn fines grains, antiphase domains and weakens dislocation clog, which retain formation of cleavage crackle. The second is that Mn decreases APB energy and promotes slop and cross slip, in particular, a large number of cross slip make deformed APBs transform from line type into zigzag type and the APBs interact and cross each other, resulting in propagation of cleavage cracks. The last is that Mn raises the relative proportion of cleavage strength to grain-boundary strength and then restrains formation and propagation of cleavage crack.

Mn对合金室温断裂行为的影响主要反映在三个方面，一是Mn的存在细化晶粒和反相畴，使得位错塞积程度减小，从而阻碍解理裂纹源的生成；二是Mn的存在提高解理强度与晶界强度的相对比值，从而抑制了解理裂纹的形成和扩展；三是Mn降低反相畴界能量、促进超位错的滑移、交滑移，特别是断裂前位错大量的交滑移使形变反相畴由直线型变为折线"Z"字型，反相畴界间的相互作用、相互交错阻碍了解理裂纹的扩展。

Combining the available regional geological and geophysical research, the petrogenesis of the magmatism was studied. As a response and absorption to the IndiaAsia collision, the northeastward flow of the asthenosphere beneath the Tibetan Plateau along the 400 km depth interface was blocked by the North China craton, and caused a systemic sequences in West Qinling Region, including the strikeslip fault systems and pullapart basins in the shallow crust and the origin of the twotype magmatism in this work in deep lithosphere. This explanation is consistent with the lithology and plumelike geochemical features of the kamafugite and potassic trachybasalt, which are significantly different from the potassic magmatism within the plateau and its adjacent regions.

结合前人对该区深部地球物理和断裂构造的研究，论证了火山岩的起源与成因，指出作为对印度-欧亚大陆强烈碰撞的吸收与调节，高原下软流圈地幔流沿400 km界面向北东方向的侧向流动以及西秦岭周边克拉通块体的阻挡，是形成西秦岭断裂系左行走滑特征和巨大拉分盆地的主要原因，也是导致西秦岭新生代两类钾质火山岩和碳酸岩起源与成因的动力学机制，较好地解释了西秦岭新生代岩浆作用起源深度大，具有地幔柱源的地球化学特征，岩石组合与地球化学有别于高原内部及其周边地区新生代钾质火山岩的原因。

First, some seismotectonic belts in southeast and northeast Qinghai-Tibet Plateau which have similar geodynamic background are selected.

本文从地震地质学角度出发，充分利用地震学和岩石力学等学科中的相关研究理论和方法，将地震活动与具体的地震构造相结合，探讨了包含多个孕震区或断裂带的大陆板内地区的地震复发规律，提出了大陆板内地震的准周期丛集复发模式，并系统、全面的研究和讨论了不同断裂之间的相互作用及其对活动断裂地震危险性的影响，从机理上揭示了大陆板内地震准周期丛集复发行为的内在物理基础。

As showed in Fig.1, the diagrammed stress of short time endurance test forAs showed in Fig.1, the diagrammed stress of short time endurance test for500 hours at 565℃on welded-joint of T91-F12 is 240MPa. Considering the℃on welded-joint of T91-F12 is 240MPa. Considering thedispersity of±20％, stress of check test for 500 hours is 192MPa. The result±20％, stress of check test for 500 hours is 192MPa. The resultof short time endurance test for 500 hours at 565of short time endurance test for 500 hours at 565℃on T91-X20CrMoV121℃on T91-X20CrMoV121welded-joints is showed in Tab.5. The result shows that the short timewelded-joints is showed in Tab.5. The result shows that the short timeendurance stress of weldedendurance stress of welded-joints with two procedures at 565℃for 500 hours-joints with two procedures at 565℃for 500 hoursboth above 192MPa, and meet the requirement.both above 192MPa, and meet the requirement.

依据图1，对T91－F12 焊接接头 565℃温度下的短时持久性能 500 小时考核试验依据图1，对T91－F12 焊接接头 565℃温度下的短时持久性能 500 小时考核试验的图示应力值应为 240MPa，按照持久强度试验数据的±20％的分散度，取 500的图示应力值应为 240MPa，按照持久强度试验数据的±20％的分散度，取 500小时考核试验应力值为 192MPa.T91－X20CrMoV121 焊接接头 565℃、500 小时小时考核试验应力值为 192MPa.T91－X20CrMoV121 焊接接头 565℃、500 小时短时持久考核试验试验结果见表5 ，试验结果表明，两种工艺条件下的焊接接头短时持久考核试验试验结果见表5 ，试验结果表明，两种工艺条件下的焊接接头565℃温度下的短时持久性能，500 小时的持久断裂应力均高于 192MPa，结果符565℃温度下的短时持久性能，500 小时的持久断裂应力均高于 192MPa，结果符合要求。

They are:①completed total 8 000 km long natural seismic profiles cross the northern boundary and central part of the plateau, identified several deep-cut lithospheric faults and low velocity and low density bodies under the central part of the plateau related to Cenozoic volcanic eruption, the Tarim block subducted beneath the Altun Mts;②found the evidence that the Altyn Tagh fault formed in 220～240 Ma and at least 400 km sinistral offset since, and determined quantitatively deformation in Cenozoic;③discovered 350 km long high-ultrahigh pressure metamorphic belt in the south border of the Qilian terrane,which brobably represented the Early Paleozoic boundary between the North China and Yangtze plates;④according to new discoveries of caledonian ophiolite,granite are subducted complex established paleo-collision orogenic framework of northern Qinghai-Tibet plateau;⑤proposed a new model .

本文展示了中法1995～2000年青藏高原北部地学研究的如下主要新进展：①完成8 000 km长的青藏高原北部及中部天然地震岩石圈探测剖面，确定若干条岩石圈断裂，发现与新生代火山喷发有关的青藏高原中部深处的低速、低密度体，塔里木地块俯冲于阿尔金山之下；②提出阿尔金断裂形成于220～240 Ma和左行平移400 km的科学依据及确定其新生代变形量；③确定祁连南缘350 km长的高压-超高压变质带，提出其可能代表早古生代时期北中国板块与扬子板块之间西部界限的新认识；④根据加里东期蛇绿岩、花岗岩及俯冲杂岩带的新发现，初步建立了古碰撞造山格架；⑤提出高原隆升的&地幔底辟和内向陆内俯冲&的新假设。

The results show that: the tensile strength, flexural strength and flexural modulus increase by about 10.4%, 62.1% and 122.3% respectively when the mass fraction of the aluminum powder increases from 0 to 50%, while elongation at break and impact strength decrease by about 65.0 and 74.4% respectively; the tensile strength, elongation at break and impact strength all increase with decreasing the particle sizes of the aluminum powders.b Nylon-12 coated metal powders for the indirect SLS process were prepared by the dissolution precipitation process. The coated powders have only 1.0 wt% nylon-12, and their SLS green parts have sufficient strength for features as small as 1.0 mm to be built and post-processed and high dimensional accuracy. The green parts were subjected to the post processing processes including binder decomposition and infiltration of epoxy resin, and then the metal/polymer composite parts with relatively high strength and accuracy were formed.At present, micron-scale inorganic fillers have been widely used to reinforce nylon SLS parts.

将该法制备的尼龙12覆膜金属粉末用于以下两个方面：a使用铝粉增强尼龙12的SLS成形件，通过溶剂沉淀法制备尼龙12覆膜铝复合粉末，研究了铝粉含量及粒径对SLS成形件性能的影响，结果表明：铝粉分散均匀，并与基体有良好的界面粘接；当铝粉含量从0增加到50wt％时，成形件的拉伸强度、弯曲强度、弯曲模量分别提高10.4％、62.1％和122.3％，冲击强度和断裂伸长率下降65.0％和74.4％，耐热性及尺寸精度也得到提高；断裂伸长率、冲击强度及拉伸强度均随着铝粉粒径的减小而增大。b使用溶剂沉淀法制备了间接法SLS用尼龙12覆膜金属粉末，该覆膜粉末中聚合物粘接剂的含量仅为1.0 wt％，其SLS初始形坯具有较高的精度以及足够满足后处理要求的强度，最小精细结构的尺寸达1.0 mm。

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。。。

The results show that the plasticity zone and dynamically quiescent layer become fine equiaxed recrystallisation under the thermo-mechanical effect, the grains in the heat-affected zone grow up because of the effect of friction heat. When the rotation speed is 2 500 r/min and the welding time is 12 s, good joint is achieved, and the tensile shear strength of the joint reaches 9.24 kN. The tensile shear strength of spot increases with increasing tool rotation speed, with increasing welding time, the strength increases first, while then reduces. The microhardness of plasticity zone is high, but is slightly lower than that of the base metal, the minimum value of microhardness is in the heat affected zone. When the energy input of joint is high, the fracture type of spot is mode Ⅰ, and the tensile shear strength is high; on the contrary, when the energy input of joint is less the fracture type of spot is mode Ⅱ, and the strength is low.

结果表明：塑性区和动态静止层的晶粒在热和力作用下发生动态再结晶形成细小的等轴晶，热影响区的晶粒在摩擦热作用下长大变粗；搅拌头旋转速度为2 500 r/min，焊接时间为12 s时，可以获得力学性能较好的焊点，焊点的剪切强度达到9.24 kN；焊点的剪切强度随搅拌头旋转速度的增大而增大，随焊接时间的延长先增大后减小；塑性区的显微硬度较高，但略小于母材，接头显微硬度的最小值分布在热影响区；焊点热输入量较多时，接头为Ⅰ型断裂，焊点的剪切强度较高；焊点热输入量较少时，接头为Ⅱ型断裂，焊点的强度较低。

P wave velocity structure in the crust of the Yellow Sea region was inverted by using P wave arrival data from the earthquakes recorded by Chinese, Korea and ISC stations. Taken together with gravity anomaly and fault system, Pn velocity and anisotropy, we analyzed the relation of various geophysical anomalies and the tectonic difference in the western and eastern Yellow Sea. This work provided further information for locating the eastern Yellow Sea fault zone and the collision boundary between the Sino-Korea and Yangtze blocks.

利用中国、韩国和ISC台站的地震走时数据反演了黄海地区的地壳P波速度结构，对比重力异常和断裂体系、Pn波速度及其各向异性，分析了不同地球物理异常的相互关系以及黄海东部和西部的结构差异，为厘定黄海东部断裂暨中朝—扬子块体的拼合边界提供了新的信息。

For maintain the genome integrity and fidelity. DNA repair processes are classified into pathways responsible for repairing specific classes of DNA damage, although recent data indicated that some proteins function in multiple pathways. Base excision repair occurs through excision of a damaged region, followed by fill-in repair synthesis using the opposite strand as a template. Mismatch repair operates on base mismatched and small loop-outs that arising during replication by misincorporation or slippage on the template strand. Nucleotide excision repair removes photoproducts from u.v. radiaton and bulky adducts from a multiple of chemicals. DNA double-strand breaks may be rectified by either homologous recombination repair and nonhomologous end joining pathways where both strands of the DNA duplex are damaged.

DNA修补基因可藉由不同的机制对不同程度的DNA损害进行修复，虽然近来已有文献指出，一些DNA修复蛋白可能参与多种DNA修复机制，不过一般可分为下列四种DNA修复机制：碱基删除修复(Base Excision Repair； BER)，即对较小的DNA损伤，进行修复；核苷酸错误配对删除修复，即对复制时所产生的核苷酸配对错误或模板滑动造成的DNA损害进行修复；核苷酸删除修复(Nucleotide Excision Repair； NER)，即对因紫外线或有机化合物所造成的较大损伤进行修复；以及双股DNA断裂修复(Double-Strand Breaks； DSBs)，即对双股DNA断裂进行修复，此机制又可分为同源染色体的重组与末端接合两种主要路径，对受损的DNA进行修复。

According to the clear water experiment, aeration performance of the new equipment is good with high total oxygen transfer coefficient and oxygen utilization ratio.

曝气设备的动力效率在叶轮转速为120rpm～150rpm时取得最大值，此时氧利用率和充氧能力也具有较高值。

The environmental stability of that world - including its crushing pressures and icy darkness - means that some of its most famous inhabitants have survived for eons as evolutionary throwbacks, their bodies undergoing little change.

稳定的海底环境─包括能把人压扁的压力和冰冷的黑暗─意谓海底某些最知名的栖居生物已以演化返祖的样态活了万世，形体几无变化。