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Search Results: 1 - 10 of 76337 matches for " 黄冲 "
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稻田养鱼生态经济效益的初步分析
卢升高,
生态学杂志 , 1988,
Abstract: ?
叶绿体分子生物学研究进展
,吴乃虎
中国生物工程杂志 , 1990,
Abstract: 叶绿体是绿色植物进行光合作用的重要细胞器。早在1909年,就有人根据高等植物叶片的花斑性状的非孟德尔遗传现象,推测叶绿体内存在着遗传物质。1954年以后,sager等人以藻类为材料,初步揭示了叶绿体母系遗传的规律。然而,直到1962年,人们才利用电镜技术首次证实了叶绿体dna(cpdna)分子的存在。十年后,才分离到cpdna分子。
旋转射流的涡声问题研究
Research on the Rotating Jet Noise Based on the Vortex-Sound Theory
 [PDF]

薛永飞, 雪芬, 涂运, 吴克启
Modern Physics (MP) , 2012, DOI: 10.12677/MP.2012.23008
Abstract:

本文针对旋转射流风机不同动静叶片间距,采用非定常结合大涡模拟的方法研究了后导叶射流风机的内流特性、外流特性及声传播问题,主要结论如下:叶轮动静间距的可调余地较大;动叶中的卡门涡和叶顶泄漏涡,以及叶片前缘产生的近壁叶道涡组成了动叶组的特色涡,涡声的源头位于前缘和尾缘;流场外侧的湍流粘性和有效粘性加剧了湍流的声音耗散;压力的时间、频率特性与声压的时频特性呈正相关的关系,声压的幅射主要位于轴线四周。

The internal flow and outflow field characteristics, and sound propagation problems of the rotating jet fan with the behind guide vanes are studied using the combination of the unsteady flow and large eddy simulation. The main conclusions are as follows: the pitch between the impeller and the guide vanes has a bigger adjustable space; the rotor blades is the main sound source surface, the Karman vortex and tip leakage vortex, and channel vortex near the wall from the leading edge is characteristics vortex of the moving blades, the sound sources of vortex generators is located in the leading and trailing edge; the turbulent viscosity and effective viscosity of outflow field intensifies the dissipation of the turbulent sound; the pressure characteristics of time and frequency shows a positive correlation to that of the sound pressure, the radiation of sound pressure mainly point to the axis around.

理想空气的配分函数研究
Study on the Partition Function of the Ideal Air
 [PDF]

雪芬, 薛永飞, 涂运, 吴克启
Modern Physics (MP) , 2011, DOI: 10.12677/mp.2011.13011
Abstract: 本文研究了空气的配分函数及其计算方法,文中分别采用统计方法和基于密度泛函理论(DFT)的量子计算方法来计算氧氮分子的配分函数,在配分函数分解定理的基础上进一步近似简化,得到氧氮分子总的内部配分函数的线性表达式。结果表明,2种方法的计算结果十分一致,简化计算结果与HITRAN数据库及国内外已有的结果进比较,误差约为1.0%。最后计算了空气的配分函数,得到结果。
The partition function of the air and its calculation method are studied in this paper. Statistical method and the quantum method which is based on the density functional theory (DFT) are used to calculate the partition functions of the oxygen molecule and nitrogen molecule. Further approximation and simplification was made here on the basis of the partition function decomposition theorem, the linear expressions of the total internal partition functions of the oxygen and nitrogen molecules were obtained. The results showed that the calculation results of these two methods were very consistent. The results of the simplified linear expressions were compared with the HITRAN database and existing results at home and abroad, the value of error was about 1%. Finally the calculation result of the partition function of the air was given.
我国各省人才聚集效应非均衡评价研究
宋磊,,
科技进步与对策 , 2012, DOI: 10.6049/kjjbydc.2011100640
Abstract: 以人才聚集八大效应为研究对象,构建了人才聚集非均衡评价模型和指标体系,并运用相对偏差模糊矩阵法进行了实证分析。研究发现:我国各省人才聚集效应已出现4大层(人才聚集效应发达层、次发达层、发展层与落后层)、9小层分化的非均衡发展阶段,呈现出信息共享效应、知识溢出效应、创新效应、集体学习效应、时间效应、规模效应与区域效应七大效应同步非均衡发展的表现形式。此结论对省际间人才聚集的协调发展具有指导意义。人才聚集效应非均衡评价相对偏差模糊矩阵
苯酐水解速率实验测定
,伍川,
南京工业大学学报(自然科学版) , 2007, DOI: 10.3969/j.issn.1671-7627.2007.01.005
Abstract: 对邻苯二甲酸酐水解反应动力学进行了研究.在线测定了溶液中ph值的变化,根据ph值与溶液浓度之间一一对应的关系,得到苯酐在水解过程中邻苯二甲酸浓度的变化.由水解结束时溶液的平衡浓度与此时溶液的ph值,计算了不同温度下邻苯二甲酸的一级电离常数ka,从而确定了水解反应级数α和不同温度下反应速率常数k.得到以下结论:随着温度的升高,水解速率常数也随之增加.根据阿伦尼乌斯方程,求得了水解反应的活化能ea为9.45kj/mol、指前因子a为2.30.
硝化纤维素-醇酸树脂-丙烯酸酯复合乳液研究
,,夏正斌
涂料工业 , 2008,
Abstract: ?首先采用相反转乳化法制得了醇酸树脂和硝化纤维素的混合乳液,然后加入丙烯酸类单体和过硫酸钾引发剂,通过自由基乳液聚合得到了硝化纤维素-醇酸树脂-丙烯酸酯复合乳液。试验研究了溶剂种类和用量、乳化剂种类和用量、醇酸树脂种类和用量、丙烯酸酯单体等因素对复合乳液及其涂膜性能的影响,并采用傅里叶红外光谱、粒径分析仪和原子力显微镜(afm)等多种方法对复合乳液及其图谋性能进行了表征。实验结果表明,以不干性油醇酸树脂、甲基丙烯酸甲酯(mma)和丙烯酸丁酯(ba)单体为主要原料,在优化的实验条件下对硝基纤维素进行改性,可制得稳定性好的硝化纤维素-醇酸树脂-丙烯酸酯复合乳液。复合乳液性能优良,其涂膜硬度为0.73,光泽度为75%,附着力为2级,可作为传统硝化纤维素的替代品而广泛用于多种水性涂料如水性木器家具涂料、皮革涂饰剂等的制备。
金属珠光色漆的静电旋杯雾化喷涂
陈峰,,王庆凯
涂料工业 , 2007,
Abstract: ?介绍金属珠光色漆静电旋杯雾化喷涂的进展以及在汽车涂装生产中的运用现状及注意事项,并就该工艺对金属漆颜色的影响进行了阐述,无风险启动方案的实施可以保证金属珠光色漆的两道旋杯喷涂工艺在生产线上顺利实现。
水稻组合气象灾害的一个实例研究
A Case Study on Overlapped Chilling with Heat Injury on Rice Crop
 [PDF]

, 熊昌元, 吴晨阳, 林俊城, 永平, 肖宇, 松井勤, 田小海
Climate Change Research Letters (CCRL) , 2013, DOI: 10.12677/CCRL.2013.24032
Abstract:
气候异常变化对作物生产的影响正日趋增大,但气候异常究竟会以何种方式影响作物生长还鲜见报道。2007 年位于江汉平原(以湖北省荆州市为中心)发生罕见的中稻结实障碍,且田间受害症状表现为典型的高、低温致害症状。通过对田间试验和大范围生产调查,对水稻受害与气候条件之间的关系进行了因果对应分析。结果表明,7 月 20 日~7 月 25 日期间,部分地区有一个罕见的降温过程,日均温低达 20℃,达到籼稻品种孕穗期敏感温度范围;8 月 6 日~8 月 10 日,部分地区出现一个连续高温天气过程,日均温或最高温度达到日均气温 ≥ 30℃或最高气温 ≥ 35℃,将各地受害程度与气象条件进行比对、综合分析,将本年度中稻结实障碍因不同地区分为 3 类,分别为低温主导型、高温主导型和低、高温叠加组合型。其中以低、高温叠加组合型危害程度最重,即它既受到减数分裂期的低温危害也受到了开花期的高温危害。此实例启示,全球气候变暖将会给作物生产造成更为复杂和严重的灾害,相应应对技术的研究显得十分紧迫。
Crops are increasingly influenced by abnormal meteorological conditions nowadays. Meanwhile we know little on how the abnormal meteorological factors would impact the crop growth. A rare sterility hazard, a typical damage from abnormal temperature, happened to mid-rice at anthesis stage in Jianghan Plain, Hubei, China in 2007. But it is bewildering to determine the exact cause for the hazard. We compared the data from field experiment, the varieties tests over the area and the meteorological records across the damaging period to find a possible cause for rice sterility. The result showed that during 20, July to 25, July, some parts of the area undergone a shape decrease of temperature, and the daily mean temperature was lower than 20?C exactly and surpassed the chilling damaging point for ear-formation. Meanwhile, from 6 August to 10 August, the time when rice was flowering, a continuous temperature lift happened, namely more than 30?C in daily mean temperature or 35?C in daily maximum temperature. In addition, the varieties that flowered at 6-13 August should undergone their meiosis stage of pollen mother cells in several days after 24 July. By matching the injuries data from the different areas against the meteorological regimes those crops experienced, we concluded with a category map of the areas in rice sterility degree: some are caused mostly by the cold weather; some are mostly by the high temperature weather; and some by an overlapped bad weather, namely cold weather at first at meiosis, then heat at anthesis. Among them, the overlapped type happened at a moderate scale in area but the loss was the biggest. This case suggests that global warming may induce more complex and severer damage to crops, so the countermeasures are urgently needed.
Study of Self-adaptive Matching Method in Chinese Segmentation Based on Decided Vocabulary
基于既定词表的自适应汉语分词技术研究

Huang Shuiqing Cheng Chong,
水清
,

现代图书情报技术 , 2006,
Abstract: This paper presents an algorithm of self- adaptive matching method in Chinese segmentation. This algorithm not only identifies Chinese words in vocabulary successfully but also identifies unlisted words which are not in vocabulary on basis of decided vocabulary automatically. The test which compares this algorithm with Reverse Maximum Matching Method and some methods which identify unlisted words proves that it can resolve unknown words segmentation effectively, decreases mistakes of Chinese segmentation and has no effect on the efficiency of Chinese segmentation largely.
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