关于条件(P)和强平坦性

利用新方法,研究了所有满足条件(P)的右S-系是强平坦系的幺半群的刻画,得到了新的幺半群类,并通过举例说明论证,所得的新结果推广了关于该问题的一些主要结论。     

陕西民营经济发展的现状、问题与对策

民营经济是社会主义市场经济的重要组成部分 ,是推动我国经济发展 ,解决就业问题的一支重要力量。改革开放以来 ,陕西民营经济已取得了很大的成绩 ,但经济总量偏小 ,经营环境较差 ,经营理念相对落后 ,经营方式与现代企业发展的要求尚有许多差距。必须从经营环境、经营理念及公司运营方式上对民营企业加以引导与改造 ,从而为陕西经济的腾飞 ,缔造西部经济强省打下坚实的基础。     

库车冰达坂昆虫初步调查

2001年6月29日--7月l0日,作对库车冰达坂-带昆虫进行初步调查，结果表明，该地区有昆虫11目31科57种。该地区的昆虫调查以前未见报导。     

谈力学中的“三大定理”与过程量、状态量的关系

力学中所研究的许多问题,都直接涉及到某一物理现象发生的整个过程,或者是过程中的某些状态。因此,相应地就引入了许多关于描述某些物理过程的过程量和用来描述某些特定的物理状态的状态量,从而来定量地分析、研究某些过程中这些物理量之间的变化关系及引起变化的原因。     

河北省隆化县七家温泉特征及成因分析

河北隆化县七家温泉历史悠久,洗浴、治病历史可远溯到隋、唐。温泉泉眼有6处,水温为30~80℃。温泉水的热储温度达174.96℃,循环深度为3 175 m。利用电法、磁法等物探方法对温泉村地热田进行勘查,确定了北北东向的两家-锦山断裂为控制地热田发育的深断裂构造,温泉多沿该断裂呈带状分布。近东西向断裂切断了两家-锦山断裂,并产生错移,使地热田分成南北两段,南段多为高温地热井群,北段广泛分布中低温温泉群。七家温泉的成因可描述为大气降水在两家-锦山断裂北段地势较高的开启处入渗地下,沿断裂通道与深部推测隐伏岩体(即热源)沟通,并获得加温,继续循环在构造交汇处涌出形成温泉,是典型的断裂-深循环型温泉。     

Shell condition and adequacy of three sympatric intertidal hermit crab populations

Shell use in relation to size adequacy and presence of physical damage and encrustation was evaluated and compared among and within three co-existing species of intertidal hermit crab (Clibanarius antillensis, C. sclopetarius and C. vittatus) in the intertidal region of Pernambuco Islet, São Sebastião Channel, south-eastern Brazil. Comparisons of shell utilization patterns among species and sexes were made with respect to physical damage (perforations and breakage in aperture and apex), encrustation by other organisms and shell size adequacy. Two adequacy indices were calculated. The visual adequacy index (VAI) was based on the degree of hermit crab retraction into the shells (1 = crab totally retracted and 6 = shield exposed). The shell adequacy index (SAI) was calculated through a comparison of the weight of the used versus the preferred shell. A relationship was found between VAI and SAI with crabs assigned as VAI = 3 occupying optimal shells (SAI = 1), i.e. crabs that could retract and those that could not retract the whole body into shells were in relatively heavier and lighter shells than the preferred ones, respectively. Shells utilized by the hermit crabs were generally undamaged and highly encrusted (except for C. antillensis) by oysters, barnacles and green algae, features that may reduce the risks of desiccation and predation. The frequent damage to the shell apertures was associated with a high abundance of shell-crushing predators in the studied area. The degree of encrustation as well as the shell adequacy (VAI and SAI) showed intra- and interspecific variation, while the presence of damage differed only among sexes (reproductive classes). In general, the smallest individuals in the populations used relatively heavier shells. Fecundity of the crabs of this assemblage is thought not to be limited by shell use once ovigerous females are occupying optimal shells.     

Data driven modeling for power transformer lifespan evaluation

Large sized power transformers are important parts of the power supply chain. These very critical networks of engineering assets are an essential base of a nation＇s energy resource infrastructure. This research identifies the key factors influencing transformer normal operating conditions and predicts the asset management lifespan. Engineering asset research has developed few lifespan forecasting methods combining real-time monitoring solutions for transformer maintenance and replacement. Utilizing the rich data source from a remote terminal unit （RTU） system for sensor-data driven analysis, this research develops an innovative real-time lifespan forecasting approach applying logistic regression based on the Weibull distribution. The methodology and the implementation prototype are verified using a data series from 161 kV transformers to evaluate the efficiency and accuracy for energy sector applications. The asset stakeholders and suppliers significantly benefit from the real-time power transformer lifespan evaluation for maintenance and replacement decision support.     

银额盆地哈日凹陷油气成藏条件研究及有利区带预测

哈日凹陷是银额盆地中北部苏红图坳陷的一个次级构造单元,该区勘探程度低,勘探效果不理想,本文综合分析其油源、储集层、盖层、圈闭等成藏条件。结果表明：下白垩统及二叠系地层均有烃源岩发育,但二叠系地层烃源岩丰度较差,目前尚未发现有效烃源岩,从有机质类型、丰度及成熟度多方面考虑,苏红图组烃源岩较好,为油气勘探重点潜力层系,银根组和巴音戈壁组为次重点潜力层系,平面上湖盆中心烃源岩发育程度最好;下白垩统储集层主要为下白垩统滨浅湖砂坝、三角洲砂体以及近岸水下扇砂体;盖层条件整体较好,同烃源岩特征一样,越向烃源岩发育程度最好的湖盆中心区域,盖层条件越好,越向凹陷边缘盖层条件越差;圈闭主要有构造圈闭和岩性圈闭,构造圈闭中又以断块和断鼻圈闭为主。油气显示指示着苏红图组为哈日凹陷的主要目的层,其次为巴音戈壁组,建立油气成藏模式,叠合成藏要素,预测苏红图组有利勘探区,有利区主要分布在延哈参1井西部的两个陡坡带上,叠合面积为23.9km2。     

农林专科学校学生英语学习现状及教学改革对策

本文针对农林专科学校学生来自边远山区和少数民族地区,学生英语基础差,对学习英语缺乏兴趣和信心的特点,对其现状进行了深入细致的分析,从教学方法、教学管理、教学模式、教学手段和师资队伍建设等方面提出了相应对策,以提高农林专科学校大学英语的教学质量。     

双万向联轴节瞬时恒定传动比条件分析

本文对双万向联轴节瞬时恒定传动比条件的原有结论作推广性分析和论证,得出一般性条件及满足该条件的机构。论证所采用的方法是以画法几何为基础的图解计算法。