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南印度洋海温异常对2020年夏季江淮流域降水的影响 被引量:1
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作者 许发雷 路瑶 李艳 《兰州大学学报(自然科学版)》 CAS CSCD 北大核心 2022年第3期347-355,共9页
从南印度洋海温异常影响的角度,利用1979-2020年NCEP和NCAR再分析资料,通过南印度洋偶极子(SIOD)指数的定义,研究2020年夏季SIOD对中国江淮流域降水异常的可能影响及大气环流原因.结果表明,1979-2019年江淮流域夏季降水与夏季SIOD指数... 从南印度洋海温异常影响的角度,利用1979-2020年NCEP和NCAR再分析资料,通过南印度洋偶极子(SIOD)指数的定义,研究2020年夏季SIOD对中国江淮流域降水异常的可能影响及大气环流原因.结果表明,1979-2019年江淮流域夏季降水与夏季SIOD指数呈显著负相关,相关系数-0.44,当SIOD指数表现为负(正)异常时,江淮流域夏季降水偏多(少);2020年夏季南印度洋海温表现为SIOD指数负位相,对应江淮流域显著的降水异常偏多.将2020年夏季的大气环流形势与1979-2019年夏季SIOD负异常年份的合成分析进行对比可见,SIOD指数负异常年,对流层高层南亚高压偏强、偏南,东亚副热带西风急流偏南;中层西北太平洋副热带高压偏强、偏北;低层西北太平洋上空水汽输送异常偏多.2020年的环流形势与一般的SIOD指数负异常年类似,但对流层中层表现为中高纬度波动强烈,环流经向度较大,有利于冷空气输送至江淮流域.利用E-P通量进行动力诊断,发现2020年和SIOD指数负异常年,均存在位于60°~80°N上空400 hPa处的辐合中心和位于24°~40°N上空250 hPa处的辐散中心,尤其是在2020年,辐合和辐散的强度更强,不仅对阻塞形势的建立有一定促进作用,有利于冷空气南下与西北太平洋副热带高压西侧的暖湿气流交汇于江淮流域,也有利于东亚副热带西风急流及低空急流加强,为江淮流域降水提供有利的水汽条件和上升运动的增强. 展开更多
关键词 南印度洋偶极子 江淮流域 夏季降水异常
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Application of nanotechnology in a silver/graphite contact material and optimization of its physical and mechanical properties 被引量:5
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作者 YUHaifeng LEIJingxuan +4 位作者 MAXueming ZHULihui luyao XIANGJing WENGWei 《Rare Metals》 SCIE EI CAS CSCD 2004年第1期79-83,共5页
By applying nanotechnology, a new type of silver/graphite (AgC) electricalcontact was fabricated and characterized. The AgC coating powders were obtained through high-energyball milling and reducer liquid spraying-coa... By applying nanotechnology, a new type of silver/graphite (AgC) electricalcontact was fabricated and characterized. The AgC coating powders were obtained through high-energyball milling and reducer liquid spraying-coating method. The as-prepared powders were examined bytransmission electron microscope (TEM), scanning electron microscope (SEM), and X-ray diffraction(XRD). The results show that the thickness of graphite flakes milled for 10 h is about 50-60 nm andthe AgC coating powders exhibit flocculent structure with quite fine and homogeneous internalmicropores. XRD implies that the average crystalline size of silver in coating powders is about 50nm. The mechanical and physical properties of this newly developed AgC contact made from theabove-mentioned nanocrystalline powders by traditional powder metallurgy technique were measured.Compared with its counterparts made from other techniques, the properties of this new AgC contacthave been optimized. High surface energy and high-energy interfaces of the nanocrystalline AgCcoating powders provide powerful driving force for sintering densification. Moreover, the flocculentstructure of the powders is also an important factor to acquire fine density ratio. 展开更多
关键词 contact material AgC-N (newly developed) NANOTECHNOLOGY high-energy ballmilling reducer liquid spraying-coating method optimization
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A MULTIDISCIPLINARY AND INTEGRATED STUDY OF RICE PRECISION FARMING 被引量:2
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作者 XIEGao-di CHENShen-bin +3 位作者 QIWen-hu luyao YANGXing-wei LIUCheng-liang 《Chinese Geographical Science》 SCIE CSCD 2003年第1期9-14,共6页
In terms of demands of rice farming in the southern China, the information processing system and the yield measurement system that is installed in combine harvester, are designed and completed. Now the systems have be... In terms of demands of rice farming in the southern China, the information processing system and the yield measurement system that is installed in combine harvester, are designed and completed. Now the systems have been used in demonstration site in the Experiment Base of Shanghai Precision Agriculture. Based on the idea of spatial-oriented, object-oriented, user-oriented, the Farm Geographic Information System for precision farming of rice was developed, which is characterized by intelligence and visualized. The Decision-making Management System is integrated with rice growth model, expert model for rice cultivation. The DGPS, RS, GIS and intelligence sensors and computer technique were adopted in building the artificial intelligence system for measuring grain yield that is installed in combine harvester, so the combine harvester could provide the grain yield distribution map real-timely. The environmental and economic assessment shows that the precision rice farming applied in the demonstration site will benefit the society, economy and ecology greatly. 展开更多
关键词 precision fanning RICE technology integration
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一测多评法同时测定心可宁胶囊中5种指标性成分的研究 被引量:2
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作者 陆瑶 李秀明 《中国药师》 CAS 2018年第4期743-746,共4页
目的:建立一测多评(QAMS)法来测定心可宁胶囊中5种指标性成分的含量。方法:采用HPLC法,以Agilent XDBC18柱(250 mm×4.6 mm,5μm)为色谱柱,流动相为乙腈-0.05%磷酸水溶液,梯度洗脱,流速1.0 ml·min^(-1),检测波长210nm,柱温30... 目的:建立一测多评(QAMS)法来测定心可宁胶囊中5种指标性成分的含量。方法:采用HPLC法,以Agilent XDBC18柱(250 mm×4.6 mm,5μm)为色谱柱,流动相为乙腈-0.05%磷酸水溶液,梯度洗脱,流速1.0 ml·min^(-1),检测波长210nm,柱温30℃。以丹酚酸B为内参物建立5种指标性成分之间的相对校正因子,分别采用外标法和一测多评法测定心可宁胶囊中5种指标性成分的含量,并对两种方法测定结果进行对比分析,以验证一测多评法的实用性与稳定性。结果:一测多评法的计算值与外标法测定值间差异无统计学意义(P>0.05),试验所得校正因子可信。结论:所建立的QAMS法可用于测定心可宁胶囊中5种指标性成分的含量。 展开更多
关键词 一测多评法 心可宁胶囊 丹参素钠 原儿茶醛 人参皂苷Rg_1 丹酚酸B 丹参酮ⅡA
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商用车辅助制动系统的联合制动控制的探讨 被引量:2
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作者 张佳琛 赵鹏昌 +2 位作者 钱治富 路遥 肖磊 《汽车实用技术》 2020年第8期105-107,共3页
当前重型商用车辆应用多种辅助制动装置成为提高行驶安全的主流方案,但是对于驾驶员提出了很高要求,同时也存在一些使用不当可能造成的风险。文章对采用发动机缸内制动和液力缓速器两种辅助制动装置的联合制动控制系统进行分析和探讨,... 当前重型商用车辆应用多种辅助制动装置成为提高行驶安全的主流方案,但是对于驾驶员提出了很高要求,同时也存在一些使用不当可能造成的风险。文章对采用发动机缸内制动和液力缓速器两种辅助制动装置的联合制动控制系统进行分析和探讨,结合车辆动力学理论和实际使用工况等内容找到一种合理的控制方案。 展开更多
关键词 商用车 发动机缸内制动 液力缓速器 联合制动
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Electrochemical Studies of Eight New Divalent Transition Metal Benzenesulphonate Ternary Complexes with 1,10-Phenanthroline
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作者 luyao GUOLi-ping +2 位作者 MAJian-fang YANGJin WUDong-mei 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第6期694-697,共4页
The electrochemical properties of eight new divalent transition metal benzenesulphonate complexes with 1,10-phenanthroline in different solvents and supporting electrolytes were investigated by means of cyclic voltamm... The electrochemical properties of eight new divalent transition metal benzenesulphonate complexes with 1,10-phenanthroline in different solvents and supporting electrolytes were investigated by means of cyclic voltammetry(CV). Based on the CV data the influences of various coordination modes on the electrochemical behavior of the complexes were discussed. The diffusion coefficient D c and rate constant k s of those complexes in DMF systems were estimated according to CV and the results show that these processes were all quasi-reversible. 展开更多
关键词 Benzenesulphonate 1 10-PHENANTHROLINE Transition metal complex Cyclic voltammetry
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单/双频混合数据的Android手机精密单点定位方法
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作者 逯遥 聂志喜 +3 位作者 王振杰 徐晓飞 张远帆 王翔 《测绘科学》 CSCD 北大核心 2023年第8期64-71,129,共9页
针对单频精密单点定位(SF-PPP)电离层误差难消除,双频精密单点定位(DF-PPP)数据少,导致单一方法定位精度低、算法收敛慢的问题,该文将SF-PPP与DF-PPP相结合,提出了一种混频精密单点定位(MF-PPP)方法。该方法对所观测到的第一频段数据采... 针对单频精密单点定位(SF-PPP)电离层误差难消除,双频精密单点定位(DF-PPP)数据少,导致单一方法定位精度低、算法收敛慢的问题,该文将SF-PPP与DF-PPP相结合,提出了一种混频精密单点定位(MF-PPP)方法。该方法对所观测到的第一频段数据采用电离层产品进行电离层改正,对有第二民用信号的数据采用消电离层观测值,综合采用两类观测值进行精密单点定位。通过仿动态、动态实验对MF-PPP方法进行了验证,结果表明在仿动态实验中,MF-PPP相对于SF-PPP在水平、垂直方向上的均方根(RMS)分别提高了33.66%、33.70%;相对于DF-PPP在水平、垂直方向上的RMS分别提高了13.22%、21.52%;在动态实验中,MF-PPP相对于SF-PPP在水平、垂直方向上的RMS分别提升了26.17%、39.17%,相对于DF-PPP在水平、垂直方向上的RMS分别提升了11.50%、21.63%。所提方法能有效提高定位精度。 展开更多
关键词 安卓智能手机 全球定位导航系统 单/双频混合数据 精密单点定位 混频精密单点定位
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