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71.
The deltaic estuarine system of the Matang Mangrove Forest Reserve of Malaysia is a site where several human settlements and brackish water aquaculture have been established. Here, we evaluated the level of fecal indicator bacteria (FIB) and the presence of potentially pathogenic bacteria in the surface water and sediments. Higher levels of FIB were detected at downstream sampling sites from the fishing village, indicating it as a possible source of anthropogenic pollution to the estuary. Enterococci levels in the estuarine sediments were higher than in the surface water, while total coliforms and E. coli in the estuarine sediments were not detected in all samples. Also, various types of potentially pathogenic bacteria, including Klebsiella pneumoniae, Serratia marcescens and Enterobacter cloacae were isolated. The results indicate that the Matang estuarine system is contaminated with various types of potential human bacterial pathogens which might pose a health risk to the public.  相似文献   
72.
An atmospheric electric field exerts a torque on both column and plate ice crystals. Columns tend to align along the direction of the field. One diameter of plate crystals also aligns parallel to a field, while a non-uniform diverging field leads to further orientation and proscribes a secondary orientation along the direction of least divergence. A laboratory investigation treats the electrical orientation of thin plate ice crystals in a non-uniform field as a two-step process. In the model, the average field provides the primary torque and aligns one diameter of the plate crystal while simultaneously a spatially varying component of the field aligns the perpendicular diameter. The first element of the process, the primary torque, has been investigated previously. The complete reorientation, caused by a secondary torque, is investigated herein. Experimentally a stronger field with sufficient non-uniformity is required to demonstrate the secondary torque. The realignment caused by this torque depends also on the strength of the aerodynamic torques on the falling ice crystals. Experiments in a laboratory cold chamber with small thin plate crystals in an electric field provided by a charged rod demonstrate crystal reorientation by changing the reflections of a beam of white light. A model incorporating electrical torques is applied to the laboratory observation and used to investigate the possibility of the effects occurring in the atmosphere. Fields near lightning strokes, which are strong but of short duration, may reorient small crystals. Larger crystal aggregates like planar snowflakes are governed by the same electrical torques. It is suggested that the secondary torque realignment might be observable for aggregates large enough to be detected by radar in cases pertaining to weaker but longer duration fields associated with cloud electrification. A simplification of the model is used to investigate electrically caused crystal motion and linear aggregation, with applications to the atmosphere and to lightning initiation.  相似文献   
73.
本文收集了1614年平遥6?级地震的各版本地震目录的参数、记录此次地震的历史史料、关于该地震的研究文献,对比了山西断陷盆地的12次5.2级至6?级历史地震和现代地震的破坏情况及有感范围,得出了此次地震的震级偏大,定为5?级更为合适的结论。同时,在前人对该地震震中参数研究的基础上,运用地震参数校订的新方法,重点定量分析了平遥一带仪器记录的小震空间分布、震群分布和地震密集值分布特征,并结合平遥一带断裂分布特征,综合分析讨论了平遥地震的震中参数。  相似文献   
74.
Space technologies, such as kinematic Global Positioning System (GPS), often combined with an inertial navigation system (INS), provide an efficient direct georeferencing tool for remote sensing and aerial surveying. Practically, these systems are now able to deliver high-precision orientation data for spatial data acquisition platforms in a timely manner, at relatively low cost, as compared to traditional methods. The Airborne Integrated Mapping System (AIMS (TM)), developed at The Ohio State University Center for Mapping, integrates high-resolution digital imagery, differential GPS/INS, and precise timing for high-quality data acquisition supporting large-scale mapping and other precise positioning applications. In this article, the AIMS (TM) system hardware/software configuration, its current operational capabilities, and the test results of airborne mapping of the coastal zone are presented.  相似文献   
75.
以大都市圈理论、区位理论、比较优势理论和共生理论为基础,从区域分工与协作的角度,探讨了在经济全球不化和市场一体化前景下,大都市上海周边的大城市苏州未来发展的区域空间定位、产业定位和城市特色定位以及实现定位的途径,为长江三角洲都市连绵区诸城市之间的协调发展提供借鉴。  相似文献   
76.
A new rock mass classification for Coal Measures Rocks   总被引:2,自引:0,他引:2  
This paper examines a new rock mass classification system (RMCR) for Coal Measures Rocks which is based on extensive laboratory testing results. The new system has been developed using 12 parameters which consist of mineral content index, uniaxial compressive strength, uniaxial tensile strength, Young's modulus of elasticity, shear strength, cohesion of rocks, angle of internal friction, point load index, cone indenter index, Cerchar index, Shore schleroscope hardness and specific energy index. The RMCR value was obtained by a number of laboratory and in situ testing results which were obtained from the coal site. The objective of the RMCR is to estimate the rock mass properties for engineering purposes.  相似文献   
77.
基于皖西大别山岳西县常年(1957~1993年)和临时测站资料以及有关的研究成果,讨论了山区作物气候生产潜力估算中有参数的计算和修正问题。给出了地形因子(海拔高度、坡向、坡度)订正后的光温水参数资料,研究了适用于大别山区不同高度上水平地表面的作物气候生产潜力计算方法,并计算了不同高度、不同坡向、不同坡度的作物气候生产潜力。  相似文献   
78.
由于硼酸盐在电解质中的特殊性 ,硼酸盐的热力学问题一直被化学家所重视。根据文献数据 ,经多种处理获得K2 B4 O7不同存在形式的硼氧配阴离子的Pitzer纯盐参数、K2 B4 O5(OH) 4电离化学计量平衡常数Km。采用所获得的Pitzer纯盐参数计算K2 B4 O7不同存在形式的硼氧配阴离子的渗透系数 ,并与表观实验值进行比较  相似文献   
79.
磁通门磁变仪实际工作在弱铁磁环境。本文分析了弱铁磁环境等对磁通门磁定仪定向的影响,得出了弱铁磁影响等环境中磁通门磁变仪准确定向的方法。  相似文献   
80.
分析了影响磁偏角磁变仪定向质量的原因,指出应重视阻尼器影响,提出磁偏角磁变仪以在实际工作环境中定向最佳,用扭头带动镜面法定向实用性强,无须做任何改正。  相似文献   
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