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991.
赵璐 《长春师范学院学报》2011,(3):54-58
中欧均衡裁军的意向是在美苏军备竞赛和规避冲突的纠葛中逐渐产生的。尼克松政府在中欧均衡裁军问题上的主要政策目标:一是利用苏联对欧安会的热衷获取其在欧洲缓和与裁军问题上的让步;二是欲通过裁军谈判缩小两大军事集团在中欧常规力量上的差距;三是借由多边裁军会议推行美国的防务分担政策,减轻自身的防务压力。中欧均衡裁军谈判作为缓解美苏军备竞赛的主要手段之一,为缓和东西方的紧张局势,缓解美国面临的国内外压力发挥了一定的作用。 相似文献
992.
993.
公司诉讼风险的影响因素已得到学术界的广泛关注,但目前的研究较少从公司融资行为角度探讨,本文以2003-2015年中国A股上市公司为研究对象,探讨超额银行借款与公司诉讼风险之间的关系.实证研究发现,公司超额银行借款与诉讼风险存在显著正相关关系,公司内部控制水平的提高以及地区法律环境的改善可以显著弱化二者的正相关关系,并且公司内部控制与地区法律环境在弱化公司超额银行借款引起的诉讼风险过程中存在相互替代的关系.本文从公司超额银行借款行为出发,拓展了公司诉讼风险影响因素的研究视角;同时结合内部控制和地区法律环境,丰富了宏观环境对公司微观主体行为影响的研究. 相似文献
994.
Natural silk from Bombyx mori has been used as medical sutures for several decades,and regenerated silk fibroin( RSF)based biomaterials have been increasingly studied in the past thirty years. However,vascular graft derived from silk fibroin fiber has been explored in recent several years with development of textile science and engineering. Moreover,endothelialization of vascular graft has been seen as an ideal strategy for preventing thrombosis and getting higher patency in a long term. Therefore,in the present work silk fibroin fiber vascular graft( SF) was chemically grafted with bioactive molecules such as heparin and RSF to improve the cytocompatibility. 3-aminopropyl-triethoxysilane(APTES),1-ethyl-3-(3-dimethylaminopropyl) carbodiie hydrochlide( EDC · HCl),and N-hydroxysuccinimide( NHS) have been employed as coupling agent and crosslinking agents,respectively. Microscopy and ATRFTIR were used to characterize the surface changes and the structure of the grafts after treatment,respectively. Cell culture in vitro and MTT assay were conducted to determine the improvement of cell affinity to the graft. Furthermore,mechanical properties of the grafts before and after treatment were compared. The results showed that the chemical grafting was an effective method for improving the cytocompatibility of SF without significant loss of mechanical properties. 相似文献
995.
叶露 《贵州师范大学学报(社会科学版)》2008,(2):104-107
文章以《莺莺传》、《霍小玉传》为切入口,认为寒门士子因追逐仕途经济之成功,不惜始乱终弃。而崔莺莺因出身甲姓,与出身卑微的霍小玉虽然处在同一时代,同为弃妇却命运殊途。作文者也因创作宗旨异趣而让后人评价不一。 相似文献
996.
高吸水性树脂的合成方法及应用前景 总被引:3,自引:0,他引:3
综述了高吸水位树脂的主要合成方法、生产概况以及应有前景,并评述了各种合成方法的优化反应条件. 相似文献
997.
Lihong Nie Zongfu Han Lahu Lu Yingyin Yao Qixin Sun Zhongfu Ni 《自然科学进展(英文版)》2008,18(5):533-538
In order to understand the genomic changes during the evolution of hexaploid wheat, two sets of synthetic hexaploid wheat from hybridization between maternal tetraploid wheat (AABB) and paternal diploid goat grass (DD) were used for DNA-AFLP and single strand conformation polymorphism (SSCP) analysis to determine the genomic and genic variation in the synthetic hexaploid wheat. Results indicated that more DNA sequences from paternal diploid species were eliminated in the synthetic hexaploid wheat than from maternal tetraploid wheat, suggesting that genome from parental species of lower ploidity tends to be eliminated preferentially. However, sequence variation detected by SSCP procedure was much lower than those detected by DNA-AFLP, which indicated that much less variation in the genic regions occurred in the synthetic hexaploid wheat, and sequence variations detected by DNA-AFLP could be derived mostly from non-coding regions and repetitive sequences. Our results also indicated that sequence variation in 4 genes can be detected in hybrid F1, which suggested that this type of sequence variation could be resulted from distant hybridization. It was interesting to note that 3 out of the 4 genes were mapped and clustered on the long arm of chromosome 2D, which indicated that variation in genic sequences in synthetic hexaploid wheat might not be a randomized process. 相似文献
998.
NECESSARY AND SUFFICIENT CONDITION FOR GLOBAL CONTROLLABILITY OF A CLASS OF AFFINE NONLINEAR SYSTEMS
Yimin SUN Shengwei MEI Qiang LU 《系统科学与复杂性》2007,20(4):492-500
In this paper, we investigate the global controllability of a class of n-dimensional affine nonlinear systems with n- 1 controls and constant control matrix. A necessary and sufficient condition for its global controllability has been obtained by using the methods recently developed. Furthermore, we generalize the above result to a class of affine nonlinear systems with a block-triangular-like structure. Finally, we will give three examples to show the applications of our results. 相似文献
999.
1000.
用食用菌菌种作为发酵菌种。用生产食用菌的方法来利用农业下脚料的废物为主料 ,发酵生产饲料或饲料添加剂 ,为食用菌的研究开发提供了新途径。 相似文献