北京山区沟域经济发展的空间结构

Valley economy is a new mode in mountainous area development that is defined by various characters of valley development, and is a distinguishing economical geographic pattern for mountainous area development. The special spatial coupling relations in the dis-tribution of different mountainous elements in valleys are new subjects for the mountain de-velopment studies, and such studies are meaningful both for researches and practices.Based on the long term researches on mountainous area development and following a brief exploration into the connotations and the spatial organizing process of valley economy, the authors analyzed the present situations of the development of valley economy in Beijing'smountainous areas, studied the characteristics and the impacts of the spatial structural changes of the valley economy in Beijing's mountainous areas, and finally proposed a rational arrangement of the spatial structure of the valley economy in Beijing's mountainous areas. It is considered in this study that valley economy plays an important role in the development and functional transformation in Beijing's mountainous areas in the new epoch. Firstly, valley economy is not outlined by the administrative boundaries, and it connects most of the villages in the mountainous areas roughly along the major transportation lines. Therefore, valley economy can exert positive influence on the development in the mountainous areas, at least in the aspects such as the rearrangement of industrial structure in the mountainous areas and the coordinated development of rural and urban areas. In addition, it is found that the valley economy in Beijing's mountainous areas is evolved in a spatial organizing stage of secondary concentration, which is characterized by resource-saving, ecological protection and industrial optimization. Therefore, the development of valley economy will be helpful to the coordination between ecological protection and economic development in the mountainous areas, and will promote the integrated development of the mountainous areas. The developing mode of the valley economy in Beijing's mountainous areas will provide the basis for the decision-making in the transformation of the functional roles of Beijing's mountainous areas, and on the other hand, will present experiences for the studies in the mountainous areas outside of Beijing.     

液体射流泵喷嘴长径比的数值分析

液体射流泵的工作喷嘴一般采用锥直形喷嘴,锥直形喷嘴出口直段的长度与喷嘴出口直径之比即喷嘴长径比,是射流泵的重要几何参数。为了研究喷嘴长径比对液体射流泵性能的影响,采用Realizableκ-ε模型对不同长径比的射流泵内部流动进行三维数值模拟。结果表明,在射流泵的流量比小于0.5时,不同喷嘴长径比所对应的射流泵效率曲线差别不大;在流量比大于0.5时,以射流泵效率为判据,喷嘴长径比范围为0.250～1.000的射流泵性能较好;不同喷嘴长径比对应的射流泵壁面剪切应力相差不大。从湍流耗散率、喷嘴出口断面收缩、核心区长度等方面考虑,喷嘴长径比范围为0.250～1.000的射流泵性能较好。     

加速剂对铝基覆铜板通孔电镀铜的影响

在由70 g/L硫酸铜、200 g/L浓硫酸、60 mg/L盐酸、200 mg/L聚乙二醇(PEG6000)和1 mg/L健那绿B(JGB)组成的基础镀液中分别添加聚二硫二丙烷磺酸钠(SPS)、3-巯基-1-丙磺酸钠(MPS)和N,N-二甲基二硫代甲酰胺丙烷磺酸钠(DPS)作为加速剂。通过计时电位曲线测试和热冲击试验,研究了不同加速剂对通孔电镀铜的影响。结果表明,镀液中添加2.5 mg/L SPS或9 mg/L DPS作为加速剂时,镀液的深镀能力显著提高,所得Cu镀层的抗热冲击性能合格。     

麦饭石矿化水及其在发酵酒中的应用

本文研究了麦饭石矿化水制备条件，麦饭石矿化水对酿造米酒和啤酒质量的影响。结果表明：麦饭石粒度和麦饭石量是影响麦饭石水矿化度的主要因素，而酸量对其影响不大。使用麦饭石矿化水使米酒前发酵酒基体积增加5．7％，糖度增加9．5％，酒精度也增加30％，还原糖含量却降低16．8％，使用麦饭石矿化水可使啤酒中双乙酰含量下降，而使其酒精度升高，促进酵母发酵，提高发酵度。同时大大增加米酒和啤酒中K，Ca,Mg,Mn,Zn,Fe,Se等有益矿物元素。     

声波透射法检测在工程建设中的应用

由于声波在混凝土传播过程中,产生的相关参数与混凝土的密实程度关系紧密,鉴于这一原理,我们在工程基桩完整性进行判断时,可根据采集到的声学参数,对混凝土的介质变化情况进行计算分析。本文首先介绍声波透射法的工作原理,其次深入探究判定混凝土缺陷性质与位置的方法,并结合工程实例说明声波透射法检测在工程建设中具有显著的应用效果,并为其他工程建设项目提供可靠的参考依据。     

适合于空间技术领域应用的Sn掺杂Mn_3GaN负热膨胀材料研究（英文）

采用球磨后放电等离子体烧结的方法制了化学成分为Mn3Ga1-xSnxN(x=0,0.1,0.2,0.3,0.4)的反钙钛矿锰氮化合物。研究了其热膨胀性能、导热性能和力学性能。结果表明:所有样品热膨胀性能与Sn含量有关,随着Sn含量的增加,负热膨胀温区向高温移动。其中,Mn3Ga0.9Sn0.1N化合物在279到338 K温区内的负热膨胀系数为–27.5×10-6 K-1,负热膨胀温区宽度为59 K。而Mn3Ga0.6Sn0.4N在363~400K温区内的热膨胀系数较小,接近零膨胀。此外,这类负热膨胀材料的热导率约为3.2 W·(m·K)-1,压缩强度约为210 MPa。     

离子液体在萃取分析领域的研究进展

离子液体是一类熔点低于100℃的有机熔融盐,通常由不对称的有机阳离子和阴离子组成,其性质可以通过改变阴阳离子组成灵活调节,被称为"设计者的溶剂"。由于其特殊的物理化学性质,离子液体在有机化学和分析化学等领域得到广泛应用,本文主要从离子液体类型、结构和性能等角度综述其在萃取前处理、色谱、毛细管电泳及电分析、光谱等领域中的研究进展,从应用机理角度对比不同离子液体在各领域应用中的优缺点,这对离子液体目前的应用状况及今后发展有较好的指导意义。通过对其发展前景的展望,表明离子液体在色谱分析和毛细管电泳等领域呈现出巨大的发展潜力。此外,设计研发新型离子液体和深入探讨其萃取分离机理,将有力推动其在分析科学领域中的研究发展,离子液体在复杂样品分析和痕量检测方面也将具有广阔的应用前景。     

以高质量规划计划服务保障流域水利发展

全面梳理“一定要根治海河”伟大号召提出60 a来特别是1980年海委成立以来海河流域规划体系、水利投资、水利建设已有的主要成就，结合规划计划工作总结出坚持规划引领、紧跟重大战略、加强前期工作、强化计划统计管理等保障流域治水发展的经验措施，根据水利高质量发展的新要求，提出下一步水利规划、建设的重点任务和工作安排。