一种远距离水位单片机智能监控系统

设计与论证一种基于AT89C51和MODEM的远距离水位智能监控系统,以普通电话线为通信线路,实现了相距约11km的蓄水池与水库泵站之间水位数据的实时传输、显示和自动控制.     

金圣叹的小说结构技巧论初探

金圣叹在评点《水浒传》时，着力探讨了长篇小说的结构技巧。首先，小说结构应是一个有机的整体；其次，小说结构应具有形式美。我们对此进行了较详细的探讨，这对建构具有民族特色的小说美学，对当今的长篇小说创作都是十分有益的。     

新疆城市环境与生态问题

本文主要论述了自然扬尘污染、水资源污染、土地资源的污染对新疆城市环境和生态环境的危害和造成的直接影响，最后提出了解决新疆城市环境与生态问题。     

Numerical investigation of cavitating flow behind the cone of a poppet valve in water hydraulic system

Computational Fluid Dynamics (CFD) simulations of cavitating flow through water hydraulic poppet valves were performed using advanced RNGk-epsilon turbulence model. The flow was turbulent, incompressible and unsteady, for Reynolds numbers greater than 43000. The working fluid was water, and the structure of the valve was simplified as a two dimensional axisymmetric geometrical model. Flow field visualization was numerically achieved. The effects of inlet velocity, outlet pressure, opening size as well as poppet angle on cavitation intensity in the poppet valve were numerically investigated. Experimental flow visualization was conducted to capture cavitation images near the orifice in the poppet valve with 30° poppet angle using high speed video camera. The binary cavitating flow field distribution obtained from digital processing of the original cavitation image showed a good agreement with the numerical result. Project supported by the National Natural Science Foundation of China (No. 59835160) and Scientific Research Foundation for Returned Overseas Chinese Scholars, State Education Ministry of China (No. 50175097)     

Modeling water and carbon fluxes above summer maize field in North China Plain with back-propagation neural networks

INTRODUCTION Dynamics of carbon and water vapor fluxesexchange between the atmosphere and the ecosystembiosphere, depend on complex and non-liner interplayamong physiological, ecological, biochemical andedaphic factors and meteorological conditions (Jarvis,1995; Leuning et al., 1995). There are many studiesquantifying the fluxes across different time and spacescales as well as assessing the environment con-straints on them by some kinds of biophysical orempirical models whose resul…     

反相高效液相色谱法测定水中荧蒽

介绍用反相高效液相色谱法测定水中荧蒽的方法,采用以硅胶为基底的C18键合相作为固相吸附载体,对水中的荧蒽进行吸附保留,用二氯甲烷洗脱荧蒽,取得了很好的回收效果.采用C8色谱柱,水和甲醇作为流动相,得出H2O∶CH3OH=20∶80时分离效果最佳,其线性回归方程为Area=0.038 182 5Amount-0.333 916,相关系数为0.999 9,相对标准偏差为0.98%～5.70%,加标回收率为96.6%～98.2%,最低检出量为15.84 ng/L.实验证明,该方法简单、快速、准确,而且回收率高,重现性好.     

Anatomical studies on water hyacinth (Eichhornia crassipes (Mart.) Solms) under the influence of textile wastewater

Water hyacinth (Eichhornia crassipes (Mart.) Solms) is a prolific free floating aquatic macrohpyte found in tropical and subtropical parts of the earth. The effects of pollutants from textile wastewater on the anatomy of the plant were studied. Water hyacinth exhibits hydrophytic adaptations which include reduced epidermis cells lacking cuticle in most cases, presence of large air spaces (7∼50 μm), reduced vascular tissue and absorbing structures. Textile waste significantly affected the size of root cells. The presence of raphide crystals was noted in parenchyma cells of various organs in treated plants. Project (No. 30070017) supported by the National Natural Science Foundation of China     

Investigation of iodine concentration in salt,water and soil along the coast of Zhejiang,China

Objective: We aim to describe the environment iodine concentration in salt, water and soil along Zhejiang Province coast in the China foreland. It will be helpful for us to judge whether this area is insufficient in iodine and universal iodized salt is necessary or not. Methods: We collected iodized salt samples, drinking water samples (tap water in the towns, and well water or spring water in the villages), water samples from different sources (ditches, lakes, rivers) and soil samples through random sampling in June, 2005. Salt, water and soil iodine was detected by arsenic-cerium redox method. Statistical analysis was expressed as mean±SEMby Windows SPSS 13.0. Results: (1) The iodine concentration in salt was 27.9±4.33 mg/kg (n=108). (2) Seventy-five water samples were collected. The water iodine value was 0.6～84.8 μg/L (mean of 11.66 μg/L). The watershed along the Qiantang River has significantly higher iodine content than the water in Lin'an in mountain area (P＜0.01). The iodine content and mean iodine content of tap water, well or spring water and natural water sources were 4.30±2.43 μg/L (n=34), 23.59±27.74 μg/L (n=19)and 12.72±10.72 μg/L (n=22) respectively. This indicated that among environmental water sources, the ditch iodine content was the highest with river water iodine being the lowest (P＜0.01). (3) Soil iodine value was 0.11～2.93 mg/kg (mean of 1.32 mg/kg).Though there was no statistical difference of soil iodine in different districts (P=0.131), soil iodine content correlated positively with water iodine content. Conclusion: Iodine concentration in salt accords with national policy of adding iodine in salt. Foreland has more iodine in water than mountain area. The data reflected that water and soil iodine in foreland area was not high, which suggests universal iodized salt should be necessary. Environment iodine has relatively close association with pollution.     

我国"民工荒"问题的深层次研究

在农村剩余劳动力存量超过1.5亿的中国,从2004年初直至2005年,在沿海地区的劳动密集型行业竟然出现了“民工荒”。虽出人意料,但又有其经济、社会、文化及政策方面的必然原因。它已经并将继续在一定程度上影响中国经济社会的发展。提高农民工待遇、企业进行转型或转移、创造良好制度环境、转变我国经济发展战略是应对“民工荒”的有效措施。     

隆中山水生植物的分布与水质初步评价

2005年4月～6月对隆中山各水体中的水生植物进行了初步调查．鉴定出水生植物11种，分属11科11属通过生物指数的分析，对隆中山的水体进行了初步的水质评价．结果表明，在所调查的8个采样点中，有2个杠塘有轻度的污染，其余水质较好．