浅析市场经济条件下水资源管理的三大转变

在市场经济条件下，水资源管理要实现三大转变：一是由传统防范和利用意识向市场资源型转变，建立起水的资源观、可持续利用观和价值观；二是由行政管水的运行机制向水市场体系转变，逐步建立起市场调节与政府调控相结合的新的管理机制；三是由政出多门的管理体制向水务一体化管理体制转变，建立起“统一、高效、负责”的水务一体化管理体制。     

Structure of a nanobody-stabilized active state of the β(2) adrenoceptor

G protein coupled receptors (GPCRs) exhibit a spectrum of functional behaviours in response to natural and synthetic ligands. Recent crystal structures provide insights into inactive states of several GPCRs. Efforts to obtain an agonist-bound active-state GPCR structure have proven difficult due to the inherent instability of this state in the absence of a G protein. We generated a camelid antibody fragment (nanobody) to the human β(2) adrenergic receptor (β(2)AR) that exhibits G protein-like behaviour, and obtained an agonist-bound, active-state crystal structure of the receptor-nanobody complex. Comparison with the inactive β(2)AR structure reveals subtle changes in the binding pocket; however, these small changes are associated with an 11?? outward movement of the cytoplasmic end of transmembrane segment 6, and rearrangements of transmembrane segments 5 and 7 that are remarkably similar to those observed in opsin, an active form of rhodopsin. This structure provides insights into the process of agonist binding and activation.     

Crystal structure of the β2 adrenergic receptor-Gs protein complex

G protein-coupled receptors (GPCRs) are responsible for the majority of cellular responses to hormones and neurotransmitters as well as the senses of sight, olfaction and taste. The paradigm of GPCR signalling is the activation of a heterotrimeric GTP binding protein (G protein) by an agonist-occupied receptor. The β(2) adrenergic receptor (β(2)AR) activation of Gs, the stimulatory G protein for adenylyl cyclase, has long been a model system for GPCR signalling. Here we present the crystal structure of the active state ternary complex composed of agonist-occupied monomeric β(2)AR and nucleotide-free Gs heterotrimer. The principal interactions between the β(2)AR and Gs involve the amino- and carboxy-terminal α-helices of Gs, with conformational changes propagating to the nucleotide-binding pocket. The largest conformational changes in the β(2)AR include a 14 ? outward movement at the cytoplasmic end of transmembrane segment 6 (TM6) and an α-helical extension of the cytoplasmic end of TM5. The most surprising observation is a major displacement of the α-helical domain of Gαs relative to the Ras-like GTPase domain. This crystal structure represents the first high-resolution view of transmembrane signalling by a GPCR.     

核能谱与两类转动惯量的精确表达式

用最小二乘拟合法,将稀土区的能谱实验数据,拟合不同的能谱公式,从而证明E=a〔(1+bI(I+1))~(1/2)-1〕是符合得较好的,本文还推导了与上述能谱相应的两类转动惯量,并以此与实验计算值进行比较,结果仍很满意.     

一种改进的规划器算法在军用软件GUI测试用例自动生成中的应用

以人工智能中智能规划方法为基础,对军用软件测试用例自动生成技术进行了研究。现有的许多规划器都不能避免组合爆炸问题的发生,而这一问题又是导致规划失败的一个重要问题,针对这一现象,以IPP规划器为例,提出目标分解法对规划器所需事实文件进行划分,并对IPP规划器应用多事实文件处理算法进行扩展,扩展后的MF-IPP规划器能够处理多个事实文档,有效避免了组合爆炸问题的发生。将该方法应用到军用主控软件GUI(Graphical User Interface)测试用例自动生成中,主要思想是首先利用规划器生成初始测试用例,其次提出解扩展的方法来完善测试用例的生成。针对测试用例生成问题进行了比对分析,结果显示,MF-IPP可以很好地防止组合爆炸问题的发生。所生成的测试用例生成时间短、覆盖率高,不仅能够很好地辅助软件测试人员进行测试用例的编写,还能应用于自动化软件测试。     

川东鄂西山地紫色土发生探讨

本文研究表明,在试验区内,地质构造决定着紫色岩层的展布和紫色土的分布;老年、壮年、青年等不同地貌发育阶段则深刻影响和制约紫色土发生演化的方向.在现代成土条件下,各地类型紫色土的发育和岩石,既存在矿质元素的相对迁移和富集.也存在元素间的彼此制约关系.实质为碱金属、碱土金属在土壤剖层次间的淋溶作用.土壤淋溶系数5.90-14.960;岩石淋溶系数2.269-4.466.     

基于DEA法的虚拟企业合作伙伴效益评价应用研究

虚拟企业合作伙伴选择是虚拟企业组建过程中的重要问题，也是一个复杂的问题。从虚拟企业合作伙伴效益评价的角度出发，在AHP(层次分析)法的基础上，给出了DEA(数据包络分析)法的C^2R模型，并结合具体企业进行了实例验证，从而证明了DEA法对于虚拟企业合作伙伴选择的科学性和有效性。     

市场化--企业安全教育的新趋向

分析了我国企业在安全教育中存在的问题，介绍了山西铝厂安全教育市场化改革的实践和效果，指明了市场化是企业安全教育发展的新趋向，同时也是企业技术教育和管理培训改革的新趋向。     

浅谈企业技术创新与信息资源开发

论述了信息在企业技术创新中的作用，并对企业技术创新信息需求的形成、内容特征及形式特征进行了分析，提出了强化信息资源开发的对策措施。