In order to research the mechanism of dynamic fracture, the fractured surface of dynamic tensile and dynamic fracture is investigated by microscope-analysis technique. The results are obtained as follows:(1) Under the condition of dynamic tensile, there is a brittle fracture feature in the local weak-link though the metals still show the ductile fracture feature.(2) The bright belt in the impact fracture surface is caused by the fatigue precrack blunt, a distribution of crack stretched zone. The width of the bright belt decreases with an increasing of the loading rate and a decreasing of the experimental temperature.(3) The dynamic crack doesn't start initiation from the crack tip, namely root of fatigue crack, but from the distance x〓 between crack tip, as the condition of cleavage crack nucleation and propagate are satisfied in there.
利用显微分析技术，对动态拉伸断口和动态断裂断口进行了微观分析，研究了动态条件下金属的断裂机理，结果表明：（1）动态拉伸的条件下，尽管宏观上金属仍表现为塑性断裂，但局部薄弱区域会表现出脆性断裂的特征；（2）冲击断口上的亮带由预制的疲劳裂纹钝化所引起，是裂纹伸张区的贡献，亮带的尺寸随加载速率的提高和温度的降低而减小；（3）动态解理裂纹并不是从裂尖，即疲劳裂纹的根部开始起裂，而是在离裂尖一定距离处x〓起裂。
Based on the results of experiments, simulation and FEM calculation, the following are found: The values of mechanical properties measured in tensile tests are lower than those measured in compression tests. The inferior properties presented in tensile tests are caused by the damages of material, which are produced at much lower applied loads before yielding and resulted in more microcracks. Many micro-cracks initiate in the elastic condition, which shows the driving force initiating a cleavage crack is the tensile stress rather than the shear stress or the plastic strain. The interlamellar strength is lower than the translamellar strength, and even lower than the yield strength. The tensile properties of duplex microstructures are higher than that of fully lamellar, on the contrary, the fracture toughness of duplex microstructure are lower than that of fully lamellar, which is related to the grain sizes in a way. The intergranular fracture and finer interlamellar fracture are the dominant fracture mechanisms in the duplex microstructure materials, the fully lamellar microstructure materials resulted in more translamellar fracture. The fatigue fracture surface and mono-bending fracture surface presents almost the same mode. The cracks extend directly from a notch or a precrack controlled by the tensile stress. The superblunting, burification and deviating from direction of tensile stress of the crack-tip fronting an obstacle are the main toughening mechanism.
在这些实验与模拟计算的基础上，我们初步分析了TiAl基合金室温断裂机理，得到了以下几个方面的结论：这种材料的拉伸与压缩性能存在很大差异，拉伸性能远低于压缩性能，在拉伸时测得比较差的性能是由于材料在很小载荷拉伸时产生微裂纹，导致了材料的损伤；大量微裂纹产生于弹性阶段，其驱动力是拉伸应力，而不是剪切应力或者塑性应变；沿层强度低于穿层强度，甚至低于屈服强度；双态组织的拉伸性能高于全层组织，而双态组织的断裂韧性低于全层组织，这与晶粒尺寸的大小有一定的关系；双态组织的断裂形态表现出更多的沿晶粒边界断裂和小沿层面断裂，而全层组织中表现出更多的穿层断裂；疲劳裂纹的断裂形态与加载过程中产生的裂纹断裂形态没有本质差别，加载过程中产生的裂纹是疲劳裂纹的延续，是逐渐扩展的过程；无论缺口试件，裂纹试件还是光滑试件，都是逐渐扩展的过程，所以解理断裂为扩展控制，控制的因素为拉伸应力；裂纹扩展时遇到取向不利的经历而引起裂纹尖端的超钝化，分叉，方向偏移是其主要的韧化机理，在裂纹很短时表现出上升的阻力曲线。
Here, the kinetic constants for the reactions of human serum apo-transferrin and bovine lactoferrin from milk with pyrophosphate and ATP are reported, and the cleavage mechanism of the pyrophosphate by these proteins is investigated, by using 31P NMR and UV-Vis spectroscopy, ESI-MS, and ICP-AES analysis.
本课题利用31P NMR及UV-Vis、ESI-MS、ICP-AES等技术，测定了人血清脱金属传铁蛋白及牛奶乳传铁蛋白与焦磷酸及ATP反应的动力学参数，研究了该酶促反应的反应机制。
And the optimal concentration of added-glucose is 50mg/L. As co-substance, phenol can improve the biodegradability of fluorophenols. The co-metabolism is the primary metabolism mechanism of these substances.(4) The coexist of fluorophenols is disadvantageous for the biodegradation because there is competition between the fluorophenols.(5) The transformation of fluorophenols was concluded to via the ortho cleavage pathway, and the fluoride ion is released after the benzene ring is cleaved.(6) The biodegradation rate of fluorophenol is markedly correlated with solution parameter, so the absorption and transformation are limited to aerobic biodegradation of fluorophenols.(7) The fluorophenol wastewater is treated with the biological aerated filter. When the gas to liquid ratio is 6:1, the hydraulic loading is 0.58m〓/ and pH value is 5.5 to 8.5, the average removal efficiency of fluorophenols is 98%. The removal of fluorophenols by BAF follows the first-order kinetics, and the constant is 2.2834h〓.
添加葡萄糖50mg／L时氟苯酚好氧生物降解性能最好；添加75mg／L苯酚时氟苯酚好氧生物降解性能最好，若添加苯酚浓度大于75mg／L，将对氟苯酚好氧生物降解产生竞争性抑制；(4)每种氟苯酚驯化污泥都可降解其它氟苯酚；当氟苯酚两两共存时，它们之间存在竞争性抑制；(5)三种氟苯酚好氧生物降解均先环断裂再脱氟，其中间产物氟邻苯二酚邻位开环降解；(6)降解性能与化学结构定量关系研究表明疏水参数与氟苯酚好氧生物降解性能的相关性最好，说明跨膜过程是氟苯酚好氧生物降解的限速步骤；(7)曝气生物滤池处理含氟苯酚废水最佳工艺参数：气水比6：1，水力负荷0.58m〓／，pH范围5.5-8.5，氟苯酚平均去除率达98％；BAF去除氟苯酚反应遵循一级反应动力学，动力学常数K为2.2834h〓。
The respective fragments m/z 176, 191, 192, 193, 161 are formed from molecular ion M~+ on the fragmentation mechanism via various cleavage modes; (2)the base peak at m/z 191 is formed with the loss of a neutral molecule via the ortho effect; (3) the base peak m/z 191 may further be cleaved to form fragments m/z 147, 132, 91; (4) the cleavage of C--N bond in si.
本文对2，6—双—4—乙基酚二盐酸盐这一对称型分子进行了精确质量和亚稳测定，证实了：(1)由分子离子M~+经过多种裂解方式，分别形成相应碎片m/z 176、191、192、193、161的裂解机理；(2)基峰m/z 191是由M~+通过邻位效应失去HN(CH_3)_2中性分子形成的；(3)基峰m/z 191可进一步裂解，通过多种途径形成m/z 147、132、91相应碎片；(4)苯环侧链胺基中C—N键的开裂与非对称型分子相似，而与脂肪胺中C—N键稳定不开裂的过程截然相反。
The contents and types of organic nitrogen compounds found in fossil fuel are introduced. Various catalysts and their catalytic active sites for HDN are summarized. The mechanism of C-N cleavage and reaction networks of dominant organonitrogen compounds in fuel fractions are discussed.
本文介绍了不同化石燃料中有机氮化物的含量及类型，对不同加氢脱氮催化剂及其催化活性位的本质进行了探讨，同时论述了C-N键断裂机理及燃料中主要有机氮化物的HDN反应网络。
This provides theoretical foundation for the outer water attack mechanism of the hydrolytic cleavage of small p...
配合物水解切割小肽的外部水进攻机理提供了理论依据。
It is found for the first time that the carbonyl oxygen coordinates to palladium in the complexes 〓 and 〓, directly providing an evidence for elucidating the hydrolytic cleavage mechanism of the peptide bonds His-Gly and Met-Gly.
首次发现配合物〓和Pd（S，N，O-AcMet-GlyH）〓中的钯与羰基氧作用，为阐明肽键His-Gly和Met-Gly的水解断裂机理提供了直接证据。
In the reactions between 1、2 excited triplet states and several chain electron poor alkenes, one charge transfer exciplex appeared as the intermediate and decayed to the ground states by the recombination of charge and intersystem crossing process. However, the reaction mechanism of 3 was some complex, after the excitation of pulsed laser, the molecules of ground state were also excited to excited singlet state, whereafter, there existed two different decay paths:(1) It could produce the excited triplet state by intersystem crossing process, then became the dimethylene triplet biradical (380 nm) with the cleavage of C-S, C-O bonds because the excited triplet state of sultine were not stable.
光敏剂3的反应机理较为复杂，在激光脉冲辐照下，其基态分子被激发至单重激发态后，其衰变途径则有两种可能：(1)通过系间窜跃变为三重激发态，而三重激发态的sultine分子由于不稳定，极易出现C-S，C-O键的断裂而生成了三重态的dimethylene双自由基。
With this system, the mechanism is studied on the cleavage of fluorescence-labeled microtubule under illumination of excitation light.
在此基础上，（1）实验研究了荧光标记的微管在激发光辐照下发生断裂的原因和机制。
Fracture observation reveals that with increasing in pressure, fracture mechanism of7075 aluminum alloy is characterized by from cleavage crack to ductile crack.
断口分析发现，随着挤压压力的增大，7075铝合金经挤压后的断裂模式由解理断裂逐渐转变为塑性断裂。
A discriminant analysis is suggested to analysis of ascertain if the tension fracture is cleavage and if the mechanism of general yield is twinning in silicon-iron.
本文对硅钢拉伸断口是否解理及硅钢全面屈服时是否属挛晶机制提出了判别分析法。
So SAP is a kind of DNA (RNA) glycosidase/depurination cleavage enzyme as it can effect on the RNA and DNA cleavage beyond retrieve. This kind of enzyme activity may be one of mechanism of anti-virus and anti-tumor effects.
SAP对核糖体RNA和超螺旋DNA的这种切割作用具有不可修复性，可以称之为DNA（RNA）糖苷酶/脱嘌呤裂解酶，这种酶活性也许是SAP抗病毒、抗肿瘤的主要作用机制之一。
The one-electron mechanism is predicted to be spin-conserved and the rate-limiting step is the cleavage of the O-H bond with 27.92 kcal/mol energy barrier.
计算结果表明，单电子机理是自旋守恒的，其决速步骤为第一步中的O-H键断裂，活化能为27.92kcal/mol。
Study on the Mechanism of Selective Carbon - Sulfur Bond Cleavage in Sulfide at Room Temperature
硫醚中碳硫键室温选择性断裂反应的研究
This provides theoretical foundation for the outer water attack mechanism of the hydrolytic cleavage of small peptides by Pd? complex.
配合物水解切割小肽的外部水进攻机理提供了理论依据。
Cleavage fracture is a typical brittle fracture and also a process consisted of crack producing and spreading, and the mechanism is related to dislocation and crystalline grain.
解理断裂是典型的脆性断裂，解理断裂也是一个裂纹萌生和扩展的过程，其机制与位错和晶粒有关。
The results of these calculations illustrate the introduction of zinc finger protein of DNA detection agent to enhance the copper nuclease DNA cleavage specificity. Thirdly, this section consists of two organic reaction mechanism.
这些计算结果说明，DNA识别剂的锌指蛋白的引入，很好地提升含铜核酸酶的DNA切割特异性。三.本部分主要研究了两个有机反应机理。
Microfracture observation showed room temperature compression fracture mechanism exhibited the combination characteristics of cleavage and ductile fracture manners.
室温压缩微观断口观察显示，经过热处理后合金的压缩断裂具有解理和韧性断裂的复合特征。
It is suggested from these results that the polymerization proceeds via a coordination-insertion mechanism involving cleavage of the acyl-oxygen bond of the lactides.
由此认为醇铁化合物是通过配位-插入机理引发丙交酯开环聚合的，链增长的过程涉及到丙交酯酰氧键的断裂并不断插入到Fe-O键中。