西秦岭三叠系一个浊积岩序列金的地球化学特征

本文在详细分析沉积韵律、沉积构造、成分及粒度的基础上,论证了四川省若尔盖县阿西乡牙相一带上三叠统卡车组一套浊积岩沉积。通过对牙相浊积岩序列的２３个采自各浊积旋回各层段的系列样品的金分析,发现这一浊积岩序列具有：以泥质粉砂岩、泥质岩为主的鲍玛序列的Ｄ—Ｅ段与其上旋回的以含砾砂岩、粗砂岩为特征的Ａ段含金量呈线性关系,表明这两段之间元Ａｕ元素发生了循环,进一步揭示了浊积岩具有金的可迁移性这一矿源层的重要特征。另外,砂质单元金含量比细粒的粉砂岩和泥岩要高,从浊积岩序列的底部旋回至上部回金的含量降低并由不稳定到稳定     

磁暴主相的經度不对称性

太阳带电粒子流通过磁边界层的中性点或阻塞点,由于极化电場的漂移运动或雷萊-泰勒（Rayleish-Taylor）不稳定运动,穿透磁层而进入地磁場被輻射带所捕获。这些被捕获的电子将向东漂移而形成西向电流。在它們围繞地球一周形成封閉的电流环以前,由于地球的自轉以及这个电流弧对地球各地的相对位置的不同,电流分布以及它在地面磁赤道附近所产生的磁場分布都将是不均匀的,对經度来耕是不对称的。本文假定电子繞地球的漂移周期为两天,計算了当磁暴开始时位于地方时00,06,12及18小时的台站記录的磁場随“暴时”T_st变化的曲线。理論結果与用佘山及洪伽幼地磁台站得到的統計結果是一致的。     

棉花耗水规律和灌溉随机控制

根据5年田间试验资料,分析了棉花产量与耗水量的抛物线关系,确定了棉花最佳耗水量;根据棉花植株在不同土壤湿度情况下气孔阻力、蒸腾强度和蕾铃脱落率的变化,确定了不同生育阶段的适宜水分指标和干旱指标。在此基础上,研制了棉花灌溉随机控制模型,可以动态预报棉田土壤有效水分含量和实际蒸散量,并从经济效益和水分利用效率的角度提出优化灌溉决策。     

基于VB可视化集成环境的测量学试题库管理系统研制

VB可视化集成开发环境以事件驱动、面向对象、图形用户界面等为特点 ,在设计试题库管理系统方面有着独特的优越性。本文通过测量学试题库管理系统的研制 ,对基于 VB建立试题库管理系统的一般方法 ,试题库的结构及功能模块、使用、特点进行研究。     

Impacts of Climatic Factors on Runoff Coefficients in Source Regions of the Huanghe River

Runoff coefficients of the source regions of the Huanghe River in 1956–2000 were analyzed in this paper. In the 1990s runoff of Tangnaihai Hydrologic Station of the Huanghe River experienced a serious decrease, which had at- tracted considerable attention. Climate changes have important impact on the water resources availability. From the view of water cycling, runoff coefficients are important indexes of water resources in a particular catchment. Kalinin baseflow separation technique was improved based on the characteristics of precipitation and streamflow. After the separation of runoff coefficient (R/P), baseflow coefficient (Br/P) and direct runoff coefficient (Dr/P) were estimated. Statistic analyses were applied to assessing the impact of precipitation and temperature on runoff coefficients (including Dr/P, Br/P and R/P). The results show that in the source regions of the Huanghe River, mean annual baseflow coefficient was higher than mean annual direct runoff coefficient. Annual runoff coefficients were in direct proportion to annual pre- cipitation and in inverse proportion to annual mean temperature. The decrease of runoff coefficients in the 1990s was closely related to the decrease in precipitation and increase in temperature in the same period. Over different sub-basins of the source regions of the Huanghe River, runoff coefficients responded differently to precipitation and temperature. In the area above Jimai Hydrologic Station where annual mean temperature is –3.9oC, temperature is the main factor in- fluencing the runoff coefficients. Runoff coefficients were in inverse relation to temperature, and precipitation had nearly no impact on runoff coefficients. In subbasin between Jimai and Maqu Hydrologic Station Dr/P was mainly affected by precipitation while R/P and Br/P were both significantly influenced by precipitation and temperature. In the area be-tween Maqu and Tangnaihai hydrologic stations all the three runoff coefficients increased with the rising of annual precipitation, while direct runoff coefficient was inversely proportional to temperature. In the source regions of the Huanghe River with the increase of average annual temperature, the impacts of temperature on runoff coefficients be-come insignificant.     

微带发夹型滤波器的设计

微带发夹型滤波器具有结构紧凑,尺寸小、重量轻和成本低等优点.根据微波电路设计的基本理论,利用微波电路ADS软件,设计了一个微带发夹型滤波器,其中心频率为2.3GHz时,通带带宽为200MHz,通带内插损小于1.7dB.仿真结果表明所设计的滤波器不仅尺寸小,而且性能优越,具有很高的实用价值.     

Urban Metabolism Based on Emergy and Slack Based Model: A Case Study of Beijing,China

The key to studying urban sustainable development depends on quantifying stores, efficiencies of urban metabolisms and capturing urban metabolisms′ mechanisms. This paper builds up the metabolic emergy account and quantifies some important concepts of emergy stores. Emphasis is placed on the urban metabolic model based on the slack based model(SBM) method to measure urban metabolic efficiencies. Urban metabolic mechanisms are discussed by using the regression method. By integrating these models, this paper analyzes the urban metabolic development in Beijing from 2001 to 2010. We conclude that the metabolic emergy stores of Beijing increased significantly from 2001 to 2010, with the emergy imported accounting for most of the increase. The metabolic efficiencies in Beijing have improved since the 2008 Olympic Games. The population, economic growth, industrial structures, and environmental governance positively affect the overall urban metabolism, while the land expansion, urbanization and environmentally technical levels hinder the improving of urban metabolic efficiencies. The SBM metabolic method and the regression model based on the emergy analysis provide insights into the urban metabolic efficiencies and the mechanism. They can promote to integrate such concepts into their sustainability analyses and policy decisions.     

频率可切换的矩形缝隙环频率选择表面

基于金属屏上周期排列的缝隙单元结构的通带特性,提出矩形缝隙环(Rectangular Slot Ring,RSR)加载短路线的单元结构实现频率可调频率选择表面(Frequency Selective Surface,FSS).谐振缝隙单元开路与短路时相对应的谐振频率分别为13 GHz和15 GHz.RSR-FSS选用Rogers RO4003介质作为基板,按照12×12的方阵进行周期排列,利用全波电磁仿真软件CST对其进行了电磁传输特性仿真.最终,通过实验验证了该频率选择表面在Ku波段通过连通和断开短路线可以进行频率的切换.     

中国对虾选育群体“黄海1号”和野生群体不同组织基因组DNA甲基化的MSAP分析

DNA甲基化在调节动物生长发育和组织分化中发挥了重要作用。本研究主要从酶切、预扩和选扩等方面优化了中国对虾DNA甲基化分析的MSAP技术,给出了适合中国对虾MSAP分析的最近反应程序和体系,并采用该技术分别对中国对虾选育群体"黄海1号"和野生群体的肌肉、鳃和血细胞三种组织基因组DNA的CCGG甲基化水平进行分析。研究结果表明,中国对虾野生群体肌肉、鳃和血细胞的DNA甲基化比例分别为23.1%、22.3%和19.7%,选育群体"黄海1号"肌肉、鳃和血液的甲基化比例分别为21.4%、19.6%和18.9%。鳃组织的DNA甲基化水平在两群体中差异极显著(P <0.01),肌肉间的甲基化水平差异显著(P <0.05),而血细胞中甲基化水平差异不显著(P >0.05)。中国对虾野生群体和"黄海1号"同一组织间的甲基化水平不同(P ≤ 0.05),而不同组织间的甲基化水平也各不相同(P ≤ 0.05)。DNA甲基化多态性分析表明,野生群体和选育群体"黄海1号"的鳃和血细胞组织的甲基化多态性比例变化明显,而肌肉组织甲基化水平较稳定,这些变化趋势与CCGG位点的甲基化和去甲基化有关。     

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