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Search Results: 1 - 10 of 32350 matches for " 沈倩 "
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引湑济黑工程水文计算复核与经济效益分析
Hydrologic Calculation and Economic Benefit Analysis of Water Transfer from Xushui River to Heihe River
 [PDF]

, , 莫淑红
Journal of Water Resources Research (JWRR) , 2012, DOI: 10.12677/JWRR.2012.16078
Abstract: 西安是一个资源性缺水城市。陕西省水利厅提出了从长江流域调水来保证关中地区经济发展的方案,引湑济黑调水工程即是其中之一。引湑济黑工程是一个跨流域调水工程,现已基本建成,但其水资源论证为2010年后补作。该论证报告有若干不足之处,应按照相关规范重新计算其调水量;且需分析研究陕西省南水北调工程建成后,该工程的运行方案,以更好地发挥其经济效益。经计算,该工程的可引水量为4661m3,与实际工程设计年引水量4248m3结果相差不大。从经济环境效益及需水量等各方面考虑,引湑济黑工程在引汉济渭建成后应继续保留,但需控制其调水量,在取水区下游用水关键时期减少或暂停调水。
Xi’an is a water shortage city. The Shanxi Water Resources Bureau put forward a plan on water transfer from theYangtzeRiver basinto guarantee economic development of the Guanzhong region. Water transfer from theXushuiRiverto theHeiheRiveris one of them. It is an inter-basin project and has been basically completed. But the water resources evaluation is added after 2010. Several deficiencies should be corrected according to the related standards. In addition, whether the operation scheme is feasible should take into account for the south-to-north water transfer project in order to exhibit the economic benefits. The calculations show that the water been obtained is46,610,000 m3and is not much different from design value which is42,480,000 m3. This project should be reserved to reduce or suspend water calls in the key period after water transfer from Han River toWeiRiver, but transferable water should be under control.
农村育龄妇女生殖生育状况的出生队列分析
,曙光
中国公共卫生 , 2000, DOI: 10.11847/zgggws2000-16-09-26
Abstract: ?用出生队列分析研究农村育龄妇女生殖生育状况的年代变化.结果显示随着出生年代渐晚,妇女月经初潮年龄逐渐提前,而绝经年龄则推迟;平均生育次数减少,生育间隔缩短;五岁以下儿童死亡数及其占活产的比例下降;节育率上升.但目前我国农村未婚先孕、先育仍相当普遍,多胎现象未被杜绝;同时妇女是节育任务的主要承担者,绝育是主要节育措施.提示对农村进一步加强计划生育宣传工作,更深入地研究安全可靠、有效易行的节育方法十分有必要
GIS设备电气联锁回路常见问题浅析
Analysis of Common Problems of GIS Equipment Electrical Interlock Circuit
 [PDF]

杜嘉寅, 杨晨,,
Journal of Electrical Engineering (JEE) , 2013, DOI: 10.12677/jee.2013.11010
Abstract: GIS组合电器设备联锁回路非常重要,直接关系到断路器、隔离开关等设备的操作,直接影响设备运行。目前经常遇到隔离开关无法操作情况,相关原因多为联锁回路发生问题。本文详细介绍了GIS设备应用的大体情况,针对典型220 kV GIS电气系统分为出线、主变、母联、PT间隔分别进行了阐述,细致分析了各类联锁回路的分类和特点,同时结合实际工作对联锁回路常见问题进行了分析并提出了整改措施和解决办法,对于相关问题的处理具有借鉴意义。
The interlock circuit of GIS equipment is very important. It is directly related to the operation of breaker and isolating switch, and affects the function of equipment. At present, we often encounter that isolating switch cannot work because of the fault in interlock circuit. This paper introduces general situation of GIS equipment and expounds the typical 220kV GIS system which is divided into: line, transformer, buscouple and PT interval. The classification and characteristics of all kinds of interlock circuit are also analyzed. Combining with the actual work, the common problems of interlock circuit are elaborated, and then the rectification measures and solutions are put forward, which are useful for dealing with related issues.
A High Performance DDFS Suitable for Digital Vedio Encoder
一种适用于数字视频编码器的高性能直接数字频率合成器

,
半导体学报 , 2001,
Abstract: A DDFS (Direct Digital Frequency Synthesizer) suitable for the digital vedio encoder is presented.By adopting the technique of noise shaping,the size of ROM is reduced to 1/8 of conventional one.The circuit size is further reduced by using other optimization methods.The worst S/N under PAL mode is 69dB,while 70 7dB under NTSC mode.
利益冲突和观念落差:“中菲南海冲突”的对外传播话语结构及其“二次传播”效果
国麟,
国际新闻界 , 2014,
Abstract: 本文以“中菲南海冲突”为例,尝试回答以下问题中国在南海问题中的对外传播话语结构是如何的?这样的话语结构在国际媒体报道中的“二次传播”效果如何?为什么会产生这样的效果?本文选取了2014年3月10日至5月20日的新华社和《中国日报》关于中菲冲突的英语报道,对其进行框架分析发现中国在这次中菲冲突中的对外传播话语结构是主权坚决捍卫;归责谴责菲律宾;解决问题不接受仲裁;对第三方的态度反对美国介入;旁观者不影响与中国关系。然后,本文又通过研究《菲律宾每日闻讯者报》和《纽约时报》在相同时间内对中菲冲突的报道发现,中国对外传播话语结构的二次传播效果并不理想,其原因有国家利益冲突、双方对于南海、中国的观念落差以及中国政府的声音很难影响国际媒体等。
酶催化荧光法测定大气水相中过氧化氢
,
环境化学 , 2015,
Abstract: 本文报道的酶催化荧光技术测定大气水相中H2O2,可以在野外采集样品,经简单前处理后带回中心实验室测定。方法的最低检测限为2×10-8M,在1×10-7M至2×10-5MH2O2浓度范围内工作曲线呈线性,在2×10-6M和1×10-5M时的变异系数小于3.0%.若用流动注射方式工作,样品量小于1ml,2—3min可以测定一个样品.
大气中硝酸和颗粒物硝酸盐的测定
,
环境化学 , 2015,
Abstract: 研究了用扩散管差分法和多种叠层滤膜法测量大气中颗粒物硝酸盐和气体硝酸.扩散管差分法可以测量颗粒物硝酸盐和气体硝酸,避免了采样时颗粒物硝酸盐的人为损失.Flouropore聚四氯乙烯膜等用性膜也可以采集颗粒物硝酸盐.其后的NaCl浸渍膜采集硝酸.而玻璃纤维膜几乎同时采集了颗粒物硝酸盐和硝酸.
扩散管差分法测定大气中氨和颗粒物铵盐
,
环境化学 , 2015,
Abstract: 本文用扩散管差分法和多种叠层滤膜法测量大气中颗粒物铵盐和气态氨.扩散管差分法可以有效分离测量颗粒物铵盐和气态氨.避免了采样时惰性滤膜上颗粒物硝酸铵分解的人为影响.
?nh3低温选择性催化还原no的研究
?吕林,
燃烧科学与技术 , 2011,
Abstract: ?在固定床反应器中,利用瞬态响应技术和程序升温技术研究了低温时nh3选择性催化还原(scr)no的瞬态动力学及v2o5-wo3/tio2催化剂活性的影响因素,试验结果表明:o2的体积分数增大,no转化率增大;h2o的存在抑制了no的转化率;so2的存在提高了no的转化率.低温时,scr反应遵循eley-rideal机理,其反应速率依赖于催化剂表面的nh3覆盖度,但当nh3覆盖度大于nh3“临界”覆盖度时,则与nh3覆盖度无关.
Fe原子在Al基底上的扩散及薄膜生长条件对磁特性的影响
Diffusion of Fe Atoms on Al Substrate and Effect of Film Growth Conditions on the Magnetic Properties
 [PDF]

, 陈俊杰, 蒋丽钦, 双娟, 黄志高
Applied Physics (APP) , 2015, DOI: 10.12677/APP.2015.512022
Abstract:
利用蒙特卡罗方法模拟Fe原子在Al基底上的沉积、扩散,以及Fe的团簇形貌的生长演化。研究了薄膜生长条件对Fe薄膜的分形形貌及磁特性的影响。模拟结果表明,随着温度的升高,Fe微观形貌经历了一个从分散成长、分形成长到凝聚成长的变化过程;而Fe薄膜的形貌极大地影响薄膜的磁特性,具有更紧凑的分形形貌的Fe薄膜具有更高的居里温度。
A Monte Carlo technique has been developed for simulating the deposition and diffusion of Fe atoms on Al (100) surfaces, and the growth of Fe clusters. The effects of growth conditions on the Fe fractal morphology and the magnetic properties are investigated. The simulated results indicate that with increasing temperature of substrate, the surface morphology evolves from dispersed growth, fractal growth to dense growth, and finally to another dispersed growth. It is also found that the morphology of Fe film greatly affects the magnetic properties, and ramified atomic aggregate with a more compact morphology has a higher Curie temperature.
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