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农村水环境管理是我国水环境管理工作的重要组成部分。本文在阐述我国农村水环境管理体制现状的基础上,分析了存在的问题,强调了改革现行体制的必要性,并提出了改革建议。 相似文献
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我国环境服务业发展现状及对策建议 总被引:1,自引:0,他引:1
环境服务业是环保产业的一个重要组成部分。本文阐述了我国环境服务业的发展现状及主要进展,分析了我国环境服务业发展的制约因素,提出了促进我国环境服务业发展的对策建议。 相似文献
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建设生态城市是可持续发展的要求。本文运用生态学理论分析了生态城市建设的内涵,阐述了生态城市建设的基本原则、生态城市系统的构架和生态城市建设的主要内容。 相似文献
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耕地的数量是粮食生产的基本保障,耕地资源是中国粮食安全的关键。基于1990—2005年的统计资料,阐述了安徽省耕地资源时序变化的特点,运用主成分分析方法对影响安徽省耕地变化的21个因子进行了分析,分析了耕地演变的机制,建立了多元线性回归预测模型,为制定耕地保护政策提供科学依据。 相似文献
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本文阐述了铝电解电容器纹波寿命试验的条件,并根据实际工作需要,对使用加倍纹波电流试验进行产品对比验证的条件、方法及用途进行了讨论,并以实际试验活动阐述此方法是可行的,通过试验快速获得对比数据并进行试验结果分析,得出相关结论。 相似文献
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舰船通信控制管理系统的可靠性设计 总被引:2,自引:0,他引:2
可靠性是军用通信设备的重要指标。本文对某舰船通信控制管理系统的可靠性指标进行了分析、预计,阐述了提高系统可靠性的各种设计措施,通过一系列的可靠性工程活动,保障了系统的可靠性达到指标要求。 相似文献
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地方环境立法是我国环境法体系的重要组成部分,本文分析了立法过程中暴露出的一些问题,并从五个方面阐述了如何推行地方环境立法建设,进而健全地方环境法体系 相似文献
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低温等离子体技术在环境工程中的研究进展 总被引:11,自引:0,他引:11
低温等离子体技术是一种用来处理环境污染问题的高新技术。介绍了低温等离子体的概念和去除污染物的机理,阐述了该技术在国内外环境工程中的应用现状,分析其存在的问题,并指出今后的发展方向。 相似文献
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用固相萃取法萃取水和废水中的多菌灵,取浓缩纯化后的有机相直接进样到高效液相色谱仪,用二极管矩阵检测器检测,根据保留时间外标法定量. 相似文献
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S. N. Nnamchi M. M. Mundu J. D. Busingye J. U. Ezenwankwo 《International Journal of Green Energy》2019,16(6):450-467
Simulation of helio-photovoltaic system is continuously undergoing revolution through diverse parameter modifications which closely mimic the experimental data. In retrospect, the current work has presented a nonlinear modification of equivalent circuit parameters and simulated the same for different semiconductors (crystalline and thin films); furthermore, established a mathematical relation between the coefficients of solar irradiance and module temperature (SIMT); moreover, investigated the influence of SIMT on the model parameters. The simulation upshot reveals that increment in solar irradiance (SI) intensifies the output current whereas an increase in module temperature (MT) diminishes the output voltage; the SIMT coefficients developed validated well with the manufacturers data; the influence of SI was evident on the photon current, diode current, and shunt resistance whereas the effect of MT was pronounced on the diode current, ideality factor, and shunt resistance. Thus, the provision made by this work is essential for advanced design and simulation of helio-photovoltaic systems. 相似文献
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激光散射技术对絮凝剂分子性能的研究 总被引:2,自引:0,他引:2
介绍以激光散射技术对絮凝剂进行的研究。利用激光散射技术实现了对絮凝剂胶体分子粒径、形态结构和粒径分布的精确测量,从而对评价该絮凝剂的沉降性能及有关性能的改进提高起指导作用。 相似文献
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This study focuses on the use of indium gallium nitride multichip for ultra-high power light emitting diode (LED) heat transfer and thermal cooling analysis. This research approach is based on the multichip LED experimental study of aluminum extrusion heat sink and air-conditioning system-forced cooling approach. An investigation of heat transfer characteristics of the phenomenon of variation is conducted to improve performance and develop an LED system that can become a reference guideline for thermal design and assembly. This study’s package structure can use silicon substrate material and fill copper material to increase thermal conduction. An air-conditioning system bypass cooling approach is also used. This study aims to help to increase LED thermal cooling, long life, reliability, and reduce the optic lumen decay phenomenon in the future. Results are based on different power ratings that can be used to redefine LED classifications. 相似文献
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Chun-An Cheng Ching-Hsien Tseng Ping-Han Feng 《International Journal of Green Energy》2018,15(5):286-295
This paper proposes a novel single-stage light-emitting diode (LED) driver with interleaved power-factor corrections (PFC) suitable for energy-saving streetlight applications. The presented circuit combines an interleaved boost PFC converter with a half-bridge-type series-resonant converter cascaded with a full-bridge rectifier into a single-stage power-conversion topology. Two inductors in the interleaved boost PFC converter sub-circuit are designed to operate in discontinuous-conduction mode (DCM) in order to achieve input-current shaping, and the half-bridge-type series-resonant converter cascaded with a full-bridge rectifier is designed to obtain zero-voltage switching (ZVS) on two power switches to reduce their switching losses. The proposed driver features high power factor, low total-harmonic distortion (THD) of input current, and high circuit efficiency, all of which results in energy savings. A prototype driver is developed and implemented to supply a 165W-rated LED streetlight module with utility-line input voltages ranging from 210 V to 230 V. In addition, satisfactory experimental results have demonstrated the feasibility of the proposed LED driver. 相似文献
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Analysis of Cell Concentration,Volume Concentration,and Colony Size of Microcystis Via Laser Particle Analyzer 总被引:1,自引:0,他引:1
The analysis of the cell concentration, volume concentration, and colony size of Microcystis is widely used to provide early warnings of the occurrence of blooms and to facilitate the development of predictive tools to mitigate their impact. This study developed a new approach for the analysis of the cell concentration, volume concentration, and colony size of Microcystis by applying a laser particle analyzer. Four types of Microcystis samples (55 samples in total) were analyzed by a laser particle analyzer and a microscope. By the application of the laser particle analyzer (1) when n = 1.40 and k = 0.1 (n is the intrinsic refractive index, whereas k is absorption of light by the particle), the results of the laser particle analyzer showed good agreement with the microscopic results for the obscuration indicator, volume concentration, and size distribution of Microcystis; (2) the Microcystis cell concentration can be calculated based on its linear relationship with obscuration; and (3) the volume concentration and size distribution of Microcystis particles (including single cells and colonies) can be obtained. The analytical processes involved in this new approach are simpler and faster compared to that by microscopic counting method. From the results, it was identified that the relationship between cell concentration and volume concentration depended on the colony size of Microcystis because the intercellular space was high when the colony size was high. Calculation of cell concentration and volume concentration may occur when the colony size information is sufficient. 相似文献
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Norris Lam Marcus Nathanson Niclas Lundgren Robin Rehnström Steve W. Lyon 《Journal of the American Water Resources Association》2015,51(5):1211-1220
This brief pilot study implements a camera‐based laser scanning system that potentially offers a viable, cost‐effective alternative to traditional terrestrial laser scanning (TLS) and LiDAR equipment. We adapted a low‐cost laser ranging system (SICK LSM111) to acquire area scans of the channel and bed for a temporarily diverted stream. The 5 m × 2 m study area was scanned at a 4 mm point spacing which resulted in a point cloud density of 5,600 points/m2. A local maxima search algorithm was applied to the point cloud and a grain size distribution of the stream bed was extracted. The 84th and 90th percentiles of this distribution, which are commonly used to characterize channel roughness, were 90 mm and 109 mm, respectively. Our example shows the system can resolve both large‐scale geometry (e.g., bed slope and channel width) and small‐scale roughness elements (e.g., grain sizes between about 30 and 255 mm) in an exposed stream channel thereby providing a resolution adequate for the estimation of ecohydraulic roughness parameters such as Manning's n. While more work is necessary to refine our specific field‐deployable system's design, these initial results are promising in particular for those working on a limited or fixed budget. This opens up a realm of laser scanning applications and monitoring strategies for water resources that may not have been possible previously due to cost limitations associated with traditional TLS systems. 相似文献