Investigation of Dynamic Fracture Toughness under Compressive-Shear Combinede Stress Wave Loading

提出亚微秒单脉冲应力波载荷作用下II型裂纹的平板冲击实验技术。加载率为dK/dt-10~8MPa·m~{”/d}·s~{-1}。实验中由锰铜应力片和弹性波理论分别测定和计算了压应力；通过微观分析确定了动态裂纹的平均扩展长度；引进等效应力强度因子,用动态断裂理论确定了60号钢的动态断裂韧性K_{Id}和K_{IId}；建立了亚微秒冲击载荷作用下确定材料动态断裂韧性的方法。

Anisotropic Deformation Of Polystyrene Particles By Mev Au Ion Irradiation

MeV An irradiation leads to a shape change of polystyrene (PS) and SiO2 particles from spherical to ellipsoidal, with an aspect ratio that can be precisely controlled by the ion fluence. Sub-micrometer PS and SiO2 particles were deposited on copper substrates and irradiated with Au ions at 230 K, using an ion energy and fluence ranging from 2 to 10 MeV and 1 x 10(14) ions/cm(2) to 1 x 10(15) ions/cm(2). The mechanisms of anisotropic deformation of PS and SiO2 particles are different because of their distinct physical and chemical properties. At the start of irradiation, the volume of PS particles decrease, then the aspect ratio increases with fluence, whereas for SiO2 particles the volume remains constant. (C) 2008 Elsevier B.V. All rights reserved.

Quantum computation based on a quantum switch in cavity QED

A feasible scheme for constructing quantum logic gates is proposed on the basis of quantum switches in cavity QED. It is shown that the light field which is fed into the cavity due to the passage of an atom in a certain state can be used to manipulate the conditioned quantum logical gate. In our scheme, the quantum information is encoded in the states of Rydberg atoms and the cavity mode is not used as logical qubits or as a communicating "bus"; thus, the effect of atomic spontaneous emission can be neglected and the strict requirements for the cavity can be relaxed.

Nd3+螯合物的含氢有机溶液光谱性能研究

Tris-thenoyltrifluroacetonate of Nd3+ has been prepared and dissolved in DMF solation with very high concentration, and the contained hydrogen has not been substituted by deuterium. The absorption spectrum, emission spectrum, and fluorescence lifetime of the solution were measured. Very obvious characteristic fluorescence peaks were observed at 898 and 1058 nm. Based on Judd-Ofelt theory, three intensity parameters were obtained: Omega(2) = 4.9 x 10(-20) cm(2), Omega(4) = 5.1 x 10(-20) cm(2) and Omega(6) = 2.5 x 10(-20) cm(2). Line strengths S-cal, oscillator strengths f(cal), radiative transition probabilities A(ed), radiative lifetimes tau(r) and branch ratios beta were calculated too. The measured lifetime tau of 1058 nm peak is 460 mu s, and that of 898 nm 505 mu s. Comparison between theoretically computed radiative lifetime tau(r)(682 mu s) and the measured lifetime indicates that the non-radiative transition probability of the solution is very low and the fluorescence quantum efficiency very high. High values of three intensity parameters prove the high asymmetric surroundings of Nd3+, which is important for Nd3+ to absorb the excitation energy. Spectropic quality factor Omega(4)/Omega(6) > 1 makes radiation at 898 nm stronger than at 1058 nm.

白宝石晶体的高温强度及强化技术研究进展

白宝石高温强度的降低主要是由于c轴方向受到压应力时产生r面双晶所引起的。高温强度的下降导致其抗热震性能降低，从而限制了白宝石晶体作为红外窗口和头罩材料的应用。白宝石晶体的强化主要以消除双晶核以及控制双晶的扩展来实现。本文分析了影响白宝石强度的主要因素，在此基础上对目前白宝石晶体强化的方法进行了总结和分析。

电镜分析非晶状体βγ晶状体蛋白与三叶因子蛋白复合物在人红细胞膜上的孔道形成效应

非晶状体βγ晶状体蛋白与三叶因子蛋白复合物(non-lens βγ-crystallin and trefoil factor complex,βγ-CAT)是一个从大蹼铃蟾(Bombina maxima)皮肤分泌物中分离的大然分子量为72kDa的全新的蛋白复合物.本研究测定了βγ-CAT处理红细胞后引起细胞内钾离子外流与溶血效应的时效曲线,结合扫描电子显微镜和透射电子显微镜分析βγ-CAT处理红细胞引起的早期形态学变化.结果表明:βγ-CAT(3 nmol/L)37℃处理红细胞5 min,(93.31±5.89)%的细胞内钾离子迅速外流(P＜0.01),相心溶解率为(13.12±1.92)%(P＜0.05).电子显微镜观察发现红细胞形态发生明显变化,细胞体枳增加,肿胀.少数红细胞表面向外形成棘状异常突起,部分肿胀细胞内的血红蛋白通过棘状突起缺口向细胞外喷射血红蛋白.表明βγ-CAT通过在红细胞膜上形成孔道使细胞内钾离子迅速外流导致红细胞内渗透压改变而溶血.其结果为理解βγ-CAT的溶血机制提供了直接的形态学证据.

Genome-wide SNP and haplotype analyses reveal a rich history underlying dog domestication

Advances in genome technology have facilitated a new understanding of the historical and genetic processes crucial to rapid phenotypic evolution under domestication(1,2). To understand the process of dog diversification better, we conducted an extensive genome-wide survey of more than 48,000 single nucleotide polymorphisms in dogs and their wild progenitor, the grey wolf. Here we show that dog breeds share a higher proportion of multi-locus haplotypes unique to grey wolves from the Middle East, indicating that they are a dominant source of genetic diversity for dogs rather than wolves from east Asia, as suggested by mitochondrial DNA sequence data(3). Furthermore, we find a surprising correspondence between genetic and phenotypic/functional breed groupings but there are exceptions that suggest phenotypic diversification depended in part on the repeated crossing of individuals with novel phenotypes. Our results show that Middle Eastern wolves were a critical source of genome diversity, although interbreeding with local wolf populations clearly occurred elsewhere in the early history of specific lineages. More recently, the evolution of modern dog breeds seems to have been an iterative process that drew on a limited genetic toolkit to create remarkable phenotypic diversity.

鱼类洄游通道恢复——国外的经验及中国的对策

简要介绍了鱼类洄游和鱼类洄游通道恢复的概念及类型。从法律与政策、资金筹措、恢复方法、恢复效果监测评估、信息交流与公众参与等5个方面介绍了欧盟、美、日、澳大利亚等国在鱼类洄游通道恢复方面积累的先进经验和成功实践,并在此基础上提出了我国鱼类洄游通道恢复应采取的对策:开展鱼类洄游通道恢复的立法和政策制定工作,加强鱼类洄游通道恢复工作的法律保障力度;开展流域阻碍鱼类洄游的障碍物调查和影响评价,制定流域鱼类洄游通道恢复规划;探索建立和完善多元化投入机制;加强鱼类洄游通道恢复研究能力建设,建立科学的技术支撑体系;开展

马来眼子菜化感作用对斜生栅藻同工酶的影响

采用聚丙烯酰胺凝胶电泳的方法,研究了马来眼子菜(Potamogeton malaianus)和斜生栅藻(Scenedesmusobliquus)共培养系统中斜生栅藻的过氧化物酶(POD)、超歧化物氧化酶(SOD)、过氧化氢酶(CAT)、细胞色素氧化酶(COD)等同工酶的变化,探讨了沉水植物化感作用对藻类部分酶类的影响。与正常生长状态的对照组相比,马来眼子菜作用下的样品组斜生栅藻POD酶带总数保持稳定,但酶谱组成发生变化;样品组斜生栅藻SOD酶带数量减少而CAT酶带数量增加。综合结果表明,样品组藻体在化感作

单苯环氯取代指数法预测二噁类化合物PCDDs的正辛醇/水分配系数

采用单苯环氯取代指数作为氯代二苯并二口恶口英类化合物 (PCDDs)的分子结构描述符 ,通过正向逐步线性回归方法建立了PCDDs的logKow与分子结构描述符之间的定量关系模型。与文献报道的MOD模型相比 ,该模型不仅具有显著的相关性 (n =43,Radj=0 898,SE =0 195 ,在α =0 0 5时 ,F =2 0 45 5 ,p =0 0 0 0 0 ) ,而且对于分子结构具有更好的区分能力。利用建立的模型 ,对没有logKow文献值的其他 33种PCDDs化合物给出了预测值

Expression pattern, cellular localization and promoter activity analysis of ovarian aromatase (Cyp19a1a) in protogynous hermaphrodite red-spotted grouper

Aromatase plays a key role in sex differentiation of gonads. In this study, we cloned the full-length cDNA of ovarian aromatase from protogynous hermaphrodite red-spotted grouper (Epinephelus akaara), and prepared the corresponding anti-EaCyp19a1a antiserum. Western blot and immunofluorescence studies revealed ovary-specific expression pattern of EaCyp19a1a in adults and its dynamic expression change during artificial sex reversal. EaCyp19a1a was expressed by follicular cells of follicular layer around oocytes because strong EaCyp19a1a immunofluorescence was observed in the cells of ovaries. During artificial sex reversal, EaCyp19a1a expression dropped significantly from female to male, and almost no any positive EaCyp19a1a signal was observed in testicular tissues. Then, we cloned and sequenced a total of 1967 bp T-flanking sequence of EaCyp19a1a promoter, and showed a number of potential binding sites for some transcriptional factors, such as SOX5, GATA gene family, CREB, AP1, FOXL1, C/EBP, ARE and SF-1. Moreover, we prepared a series of 5' deletion promoter constructs and performed in vitro luciferase assays of EaCyp19a1a promoter activities. The data indicated that the CREB regulation region from -1010 to -898 might be a major cis-acting element to EaCyp19a1a promoter, whereas the elements GATA and SOX5 in the region from -1216 to -1010 might be suppression elements. Significantly, we found a common conserved sequence region in the fish ovary-type aromatase promoters with identities from 93% to 34%. And, the motifs of TATA box, SF-1, SOX5, and CREB existed in the region and were conserved among the most of fish species. (C) 2009 Elsevier Ireland Ltd. All rights reserved.