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Variability of complementary relationship and its mechanism on different time scales

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Science China(Technological Sciences) 2009年第4期52卷 1059-1067页

作者： YANG HanBo YANG DaWen lei zhidong SUN FuBao CONG ZhenTao State Key Laboratory of Hydro-Science and Engineering Department of Hydraulic EngineeringTsinghua UniversityBeijing 100084China

In the complementary relationship (CR) between actual and potential evapotranspiration, wet envi- ronment evapotranspiration (Ew) is usually calculated using the Priestley-Taylor (P-T) equation. Based on the data obtained from 38 catchments of the Haihe River basin and the Weishan experiment site in Shandong Province of China, this study has found variations in the Priestley-Taylor parameter α (e.g. increase in values with increase in the amount of precipitation on annual scale, seasonal fluctuation noted to be at a maximum during winter and at a minimum during summer, and increased values in the forenoon and decreased values in the afternoon on an hourly scale). This paper explains that the in- ter-annual variation in α is due to the negative feedback of atmosphere in response to changes in ac- tual increase in evapotranspiration, which is weakened because the atmosphere system is open. The parameter α undergoes a seasonal fluctuation brought about by seasonal changes in advection be- tween continent and ocean; α likewise undergoes a daily variation as a result of atmospheric hysteresis in response to the changes in land surface energy.

关键词： complementary relationship temporal scales wet environment evapotranspiration Priestley-Taylor equation state space

Environmentally friendly solders 3-4 beyond Pb-based systems

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Rare Metals 2006年第Z2期25卷 95-100页

作者： GAO Yuan LIU Peng GUO Fu XIA zhidong lei Yongping SHI Yaowu College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China College of Materials Science and Engineering Beijing University of Technology Beijing 100022 China

Based on environmental considerations, global economic pressures, enacted by legislations in several countries, have warranted the elimination of lead from solders used in electronic applications. Sn3.5Ag, SnAgCu, and Sn0.7Cu have emerged among various lead-free candidates as the most promising solder alloys to be utilized in microelectronic industries. However, with the vast development and miniaturization of modern electronic packaging, new requirements such as superior service capabilities have been posed on lead-free solders. In order to improve the comprehensive property of the solder alloys, two possible approaches were adopted in the current research and new materials developed were patented. One approach was involved with the addition of alloying elements to make new ternary or quaternary solder alloys. Proper addition of rare earth element such as La and Ce have rendered solder alloys with improved mechanical properties, especially creep rupture lives of their joints. Another approach, the composite approach, was developed mainly to improve the service temperature capability of the solder alloys. Composite solders fabricated by mechanically incorporating various reinforcement particles to the solder paste have again exhibited enhanced properties without altering the existing processing characteristics. The recent progress and research efforts carried out on lead-free solder materials in Beijing University of Technology were reported. The effects of rare earth addition on the microstructure, processing properties, and mechanical properties were presented. The behaviors of various Sn-3.5Ag based composite solders were also explicated in terms of the roles of reinforcement particles on intermetallic growth, steady-state creep rate, the onset of tertiary creep, as well as the overall creep deformation in the solder joints. Thermomechanical fatigue (TMF) behavior of the solder alloys and composite solders were investigated with different parameters such as ramp

关键词： lead-free solder composite solder no-clean flux creep mechanical properties thermomechanical fatigue

叶尔羌灌区冬小麦生育期 SPAC 水热传输的模拟研究

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水利学报 1998年第7期29卷 35-40,45页

作者： Mao Xiaomin Yang Shixiu lei zhidong (Tsinghua University) 清华大学水利水电工程系北京

本文应用土壤水动力学、微气象学和能量平衡原理，建立了作物生育期土壤植物大气连续体（ＳＰＡＣ）的水热迁移和转化模型，并采用全隐式有限差分方法进行离散，通过自动调节计算步长和反复迭代等方法设计了数值模拟程序．运用本模... 详细信息

本文应用土壤水动力学、微气象学和能量平衡原理，建立了作物生育期土壤植物大气连续体（ＳＰＡＣ）的水热迁移和转化模型，并采用全隐式有限差分方法进行离散，通过自动调节计算步长和反复迭代等方法设计了数值模拟程序．运用本模型对新疆叶尔羌河流域地下水均衡场１９９５年３月～６月冬小麦返青至成熟期的田间水热状况进行了模拟．结果证明，该模型较真实地反映了非冻结期作物生长过程中土壤中的水热状况以及地表和作物蒸散发的动态变化过程，可用于墒情预报以及农田蒸散发的研究．

关键词：水热迁移蒸散发数值模拟灌区冬小麦

Activity Screening Study on the Anti-tumor Effects of Extracts from Mahoniae caulis

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Medicinal Plant 2023年第6期14卷 19-21,26页

作者： Xin XIE Liyuan LI Aipeng LI zhidong lei Suoyi HUANG School of Basic Medical Sciences Youjiang Medical University for NationalitiesBaise 533000China School of Pharmacy Youjiang Medical University for NationalitiesBaise 533000China Key Laboratory of Characteristic Ethnic Medicine Research in Youjiang Basin Youjiang Medical University for NationalitiesBaise 533000China

[Objectives]To explore the anti-tumor activity of the extracts of petroleum ether,ethyl acetate,n-butanol and aqueous solution from Mahoniae caulis.[Methods]The extracts were extracted with petroleum ether,ethyl acetate,n-butanol and aqueous solution respectively,and then *** inhibitory effects of these extracts on the growth of three tumor cell lines in vitro were detected by CCK-8 method,and the IC 50 value was calculated.[Results]The four extracts inhibited the growth of the three tumor cell lines in vitro,among which the n-butanol extract had the best anti-tumor *** IC 50 values of the n-butanol extract on human gastric cancer(SGC-7901),human breast cancer(MCF-7)and human liver cancer(BEL-7404)cell lines were 0.23,0.25 and 0.58 mg/mL,respectively.[Conclusions]The ethanol extract of Mahoniae caulis under petroleum ether,ethyl acetate,n-butanol and aqueous solution had certain anti-tumor effect,and n-butanol extract had the best anti-tumor activity.

关键词： Mahoniae caulis Tumor cells Anti-tumor effects Activity screening

一种基于预测和变换混合设计的超光谱图像压缩方法

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航空学报 2010年第4期31卷 754-761页

作者：陈雷张晓林杨维松雷志东北京航空航天大学电子信息工程学院北京100191

提出了一种新的超光谱图像压缩方法。该方法针对三维小波压缩编码方法对专有数据的特殊属性利用效率较低的缺陷,设计了一种应用于超光谱图像的预测编码和变换编码相混合的实现方案。首先,由超光谱图像的高谱间相关性,推导出图像各波段... 详细信息

提出了一种新的超光谱图像压缩方法。该方法针对三维小波压缩编码方法对专有数据的特殊属性利用效率较低的缺陷,设计了一种应用于超光谱图像的预测编码和变换编码相混合的实现方案。首先,由超光谱图像的高谱间相关性,推导出图像各波段间的一般表达式。然后,根据这一表达式建立了超光谱图像的波段预测方式。该预测方式以波段为单位,参考波段采用小波变换编码技术进行压缩。为了提高预测的精度,参考波段选择器和波段预测器分别基于超光谱图像的数学统计规律和各波段直方图形状相似的特性进行设计。最后,将预测偏差值通过三维小波编码技术进行压缩。实验结果表明,本文设计的方法与目前先进的超光谱压缩技术相比能够提供具有竞争力的性能提升,且具有良好的兼容性、灵活性和渐进传输能力。

关键词：超光谱图像有损压缩预测编码变换编码小波变换

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田间土壤水分入渗的空间分布

水利学报 1987年第3期 1-9页

作者：雷志栋杨诗秀清华大学

本文利用已有的土壤水分运动参数标定成果,用数值方法求解了标定的土壤水分运动基本方程,得出了某一初始含水率分布条件下、薄层积水时土壤水分运动入渗的标定解.作为示例,给出了不同标定因子地点处的土壤水分入渗过程.本文还介绍了Phi... 详细信息

本文利用已有的土壤水分运动参数标定成果,用数值方法求解了标定的土壤水分运动基本方程,得出了某一初始含水率分布条件下、薄层积水时土壤水分运动入渗的标定解.作为示例,给出了不同标定因子地点处的土壤水分入渗过程.本文还介绍了Philip入渗公式的标定方法,结合在河南、山东二省所进行的三组入渗试验资料,对入渗标定因子的确定、入渗量的标定及入渗量的空间分布等问题进行了初步计算和分析.

关键词：田间土壤土壤水分运动入渗试验标定因子入渗下渗人渗空间分布

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冬小麦田间墒情预报的经验模型

农业工程学报 2000年第5期16卷 31-33页

作者：尚松浩雷志栋杨诗秀清华大学

基于土壤水分变化率与贮水量成正比这一假定 ,得出了土壤水分的指数消退关系。在此基础上 ,建立了冬小麦生育期土壤墒情预报的经验递推模型 ,并对模型进行了检验 ,表明模型预报效果较好。该模型的特点是模型简单且参数较少 ;其主要局限... 详细信息

基于土壤水分变化率与贮水量成正比这一假定 ,得出了土壤水分的指数消退关系。在此基础上 ,建立了冬小麦生育期土壤墒情预报的经验递推模型 ,并对模型进行了检验 ,表明模型预报效果较好。该模型的特点是模型简单且参数较少 ;其主要局限性是模型中土壤水分消退系数地域。

关键词：冬小麦土壤水分消退墒情预报经验模型

TFEL of Ce^(3+) in zine sulpho-oxide

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Chinese Science Bulletin 1998年第14期43卷 1179-1183页

作者： YU lei\+1, LOU zhidong\+1, XU Chunxiang\+1, XU Zheng\+2 and XU Xurong\+2 1. Institute of Material Physics, Tianjin Institute of Technology, Tianjin 300191, China 2. Department of Physics, Northern Jiaotong University, Beijing 100044, China Institute of Material Physics Tianjin Institute of Technology Tianjin China Department of Physics Northern Jiaotong University Beijing China

A new TFEL material ZnS X O 1-X : Ce 3+ is prepared. The EL brightness of ZnS X O 1-X : Ce 3+ is at least one order higher than that of ZnS: Ce 3+ at the same doping concentration of Ce 3+ . The EL emission wavelength of ZnS X O 1-X : Ce 3+ (\%X\%=0.5) ranges from 400 to 600 nm. The emission of ZnS X O 1-X : Ce 3+ may be used as the blue part of white TFEL.

关键词： thin_film electroluminescence (TFEL) filter layered optimization zine sulpho_oxide.

鸡骨草生物活性成分及其提取方法与产量提升研究进展

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中华中医药学刊 2020年第10期38卷 210-214页

作者：雷智冬黄锁义广西中医药大学药学院广西南宁530001 右江民族医学院药学院广西百色533000 右江民族医学院广西高校右江流域特色民族药研究重点实验室广西百色533000

目的对鸡骨草的生物活性成分及生物活性成分的提取方法等进行阐述说明,旨在提高对鸡骨草生物活性成分重要价值的认识,为充分开发鸡骨草产品,发展鸡骨草产业提供参考。方法通过查阅书籍资料,查阅国内外文献,对鸡骨草中的生物活性在活性... 详细信息

目的对鸡骨草的生物活性成分及生物活性成分的提取方法等进行阐述说明,旨在提高对鸡骨草生物活性成分重要价值的认识,为充分开发鸡骨草产品,发展鸡骨草产业提供参考。方法通过查阅书籍资料,查阅国内外文献,对鸡骨草中的生物活性在活性成分、成分含量、提取方法以及如何提升这些生物活性成分含量等进展进行综述。结果鸡骨草富含多种生物活性,源于多糖类、黄酮类、生物碱类、三萜类、挥发油、蒽醌类化合物、微量元素和其他种类等多种化学成分;鸡骨草具有多种生物活性,其中以抗肿瘤及抗氧化生物活性研究广泛;鸡骨草生物活性成分的提取方法主要以溶剂提取法、超声提取法为主;规范化种植和科学性施肥与鸡骨草生物活性成分的含量相关。结论鸡骨草的化学成分丰富,使其生物活性多样,在食品、保健品、药品及化妆品等行业具有较好的应用潜力;但如今实验研究发现的有生物活性的化学成分极少。因此,鸡骨草有进一步开发的价值。

关键词：鸡骨草生物活性成分生物活性提取方法产量提升