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农田土壤养分平衡状况及其评价的试点研究

土壤肥料 2000年第6期 14-19页

作者：黄绍文金继运左余宝杨俐苹程明芳中国农业科学院土壤肥料研究所北京100081

本文研究了黄淮海平原二个主要农业自然经济类型区定位监测点的农田土壤养分收支平衡状况 ,并用养分允许平衡盈亏率进行评价。玉田县和陵县试区 ,N盈余分别平均为 82 .7～10 7.1、32 .0～ 184 .2 kg/ hm2 .a,可能会造成 N素的大量损失... 详细信息

本文研究了黄淮海平原二个主要农业自然经济类型区定位监测点的农田土壤养分收支平衡状况 ,并用养分允许平衡盈亏率进行评价。玉田县和陵县试区 ,N盈余分别平均为 82 .7～10 7.1、32 .0～ 184 .2 kg/ hm2 .a,可能会造成 N素的大量损失和引起较严重的环境污染 ;P2 O5盈余分别平均为 2 1.1～ 2 2 .9、74 .3～ 77.5kg/ hm2 .a,玉田县试区磷肥的施用基本合理 ,而陵县试区磷肥未得到合理高效利用 ;K2 O亏缺分别平均为 54.2～ 78.5、183.3～ 2 16.7kg/ hm2 .

关键词：农田土壤养分支出参数养分平衡平衡盈亏率

Effect of the geometric shapes of specimens on impact tensile tests

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第10期11卷 817-821页

作者： Wei-fang XU Xi-cheng HUANG Zhi-ming HAO Yang WANG Yuan-ming XIA Department of Modern Mechanics University of Science and Technology of China Hefei 230027 China Institute of Structural Mechanics China Academy of Engineering Physics Mianyang 621900 China

The geometric shapes of specimens are important in impact tensile tests because geometric shapes determine the stress states of the specimens, and precise geometric shapes can obtain proper material properties without non-material factors. The aim of this study was to investigate the 1D form of the stress by changing the length-to-diameter (L/D) ratios of specimens. The experiments were carried out on a split Hopkinson tensile bar (SHTB)-rotating disk indirect bar-bar tensile impact apparatus. The L/D ratios of the LY12CZ specimens used in the test ranged from 1 to 5. Results show that the specimens can be used to obtain exact parameters of materials under the proposed conditions when the L/D ratio is greater than 2. This is because the longer length will reduce or eliminate the effects of the interfaces.

关键词： Impact tensile Split Hopkinson tensile bar (SHTB) Length-to-diameter (L/D) ratios

A General Additive-multiplicative Rates Model for Recurrent and Terminal Events

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Acta Mathematicae Applicatae Sinica 2015年第4期31卷 1115-1130页

作者： Xi-ming cheng fang-yuan KANG Jie ZHOU Xin WANG School of Applied Science Beijing Information Science and Technology University School of Mathematical Science Capital Normal University

Recurrent events data with a terminal event （e.g. death） often arise in clinical and observational studies. Most of existing models assume multiplicative covariate effects and model the conditional recurrent event rate given survival. In this article, we propose a general mSditive-multiplicative rates model for recurrent event data in the presence of a terminal event, where the terminal event stop the further occurrence of recurrent events. Based on the estimating equation approach and the inverse probability weighting technique, we propose two procedures for estimating the regression parameters and the baseline mean function. The asymptotic properties of the resulting estimators are established. In addition, some graphical and numerical procedures are presented for model checking. The finite-sample behavior of the proposed methods is examined through simulation studies, and an application to a bladder cancer study is also illustrated.

关键词： additive-multiplicative rates estimating equation marginal model model checking recurrentevents terminal event

Numerical investigation of the wind environment around tall buildings in a central business district

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Frontiers of Earth Science 2019年第4期13卷 848-858页

作者： Pingzhi fang Deqian ZHENG ming GU Haifeng cheng Bihong ZHU Shanghai Typhoon Institute of China Meteorological Administration Shanghai 200030China School of Civil Engineering and Architecture Henan University of TechnologyZhengzhou 450001China State Key Laboratory for Disaster Reduction in Civil Engineering Tongji UniversityShanghai 200092China Shanghai Investigation Design&Research Institute Co.Ltd.Shanghai 200335China

The wind environment around tall buildings in a central business district(CBD)was numerically *** district covers an area of-^4.0 km2 and features a high density of tall *** this study,only buildings taller than 20 m were considered,resulting in 173 tall buildings in the *** numerical investigation was realized using the commercial computational fluid dynamics code FLUENT with the realizable A-6:turbulence *** efforts were made to maintain inflow boundary conditions throughout the computational *** reliability of the numerical method was validated using results from an experimental investigation conducted in the core area of the CBD(〜1.5 km2).Experimental and numerical investigations of wind speed ratios at the center of the three tallest buildings in the CBD agree within an uncertainty factor of *** the experimental and numerical results show that wind speed ratios in the wind field with exposure category D are higher than those from the wind field with exposure category *** on the above validation work,the wind environment around tall buildings in the whole CBD was then investigated by numerical *** flow phenomena and patterns,such as stagnation points,shielding effects,separation flow,and channeling flow,were identified around the tall *** pedestrianlevel wind environment around tall buildings in the CBD was further evaluated using nearby meteorological wind *** evaluation results show that some pedestrian activities,such as sitting at the center of the three tallest buildings,are unadvisable when the wind blows from the south-east.

关键词： wind environment pedestrian-level wind computational fluid dynamics wind speed ratio central business district

Stress release in high-capacity flexible lithium-ion batteries through nested wrinkle texturing of graphene

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Journal of Energy Chemistry 2021年第10期30卷 243-249,I0008页

作者： Jing Chen Lei Wen Ruopian fang Da-Wei Wang Hui-ming cheng Feng Li Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016LiaoningChina School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026.AnhuiChina School of Chemical Engineering The University of New South WalesSydney 2052Australia Tsinghua-Berkeley Shenzhen Institute Tsinghua UniversityShenzhen 518055GuangdongChina

Flexible lithium-ion batteries(LIBs)are critical for the development of next-generation smart *** reaction-based electrodes have been considered promising to construct high energy-density flexible LIBs,which satisfy the ever-increasing demand for practical ***,these electrodes suffer from inferior lithium-storage performance and structural instability during deformation and long-term lithiation/*** are caused by the sluggish reaction kinetics of active-materials and the superposition of responsive strains originating from the large lithiation-induced stress and applied ***,we propose a stress-release strategy through elastic responses of nested wrinkle texturing of graphene,to achieve high deformability while maintaining structural integrity upon prolonged cycles within high-capacity *** wrinkles endow the electrode with a robust and flexible network for effective stress *** resulting electrode shows large reversible stretchability,along with excellent electrochemical performance including high specific capacity,high-rate capability and long-term cycling *** strategy offers a new way to obtain high-performance flexible electrodes and can be extended to other energy-storage devices.

关键词： Wrinkling graphene Structural design Stress release High-capacity active material Flexible electrodes

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基于最小阻力模型的武安市景观安全格局研究

资源开发与市场 2017年第12期33卷 1417-1421页

作者：魏聪礼张建军程明芳耿晓丽中国地质大学(北京)土地科学技术学院北京100083 国土资源部土地整治重点实验室北京100035

矿产资源的开采虽然使资源型城市的社会经济迅猛发展,但也造成了环境污染和景观安全格局破坏。以资源型城市武安市为研究区,基于"源—汇"理论和最小阻力模型,确定武安市的"生态源"和"干扰源",构建综合阻力面,提取重要生态廊道,分析其景... 详细信息

矿产资源的开采虽然使资源型城市的社会经济迅猛发展,但也造成了环境污染和景观安全格局破坏。以资源型城市武安市为研究区,基于"源—汇"理论和最小阻力模型,确定武安市的"生态源"和"干扰源",构建综合阻力面,提取重要生态廊道,分析其景观安全格局状况。研究结果表明:(1)"生态源"集中分布在武安市西部自然保护区,中东部分布较少且连通性差;(2)矿产资源开采区的生态阻力值较大,交通建设对生态过程扩展起阻碍作用;(3)生态廊道网络布局特征明显,南、北氵名河连贯东西,南北方向因生产建设干扰强烈出现断层;(4)矿区周围生态用地破碎严重,应将生态规划与城市规划、矿区规划相结合,整体上保护资源型城市的景观生态安全格局。

关键词：景观生态安全格局 MCR模型武安市生态廊道

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楚雄盆地与四川盆地中西部地质条件对比分析

地质学刊 2009年第3期33卷 235-238页

作者：彭金宁刘光祥方成名陆永德中石化勘探开发研究院无锡石油地质研究所江苏无锡214151

通过楚雄盆地与四川盆地中西部区域地质条件和油气地质条件的对比研究,探讨了楚雄盆地与四川盆地中西部地区盆地性质、沉积序列、油气地质条件等方面的异同点,从而给楚雄盆地的油气勘探一些启示:它们间的基本地质特征、油气地质特征类似... 详细信息

通过楚雄盆地与四川盆地中西部区域地质条件和油气地质条件的对比研究,探讨了楚雄盆地与四川盆地中西部地区盆地性质、沉积序列、油气地质条件等方面的异同点,从而给楚雄盆地的油气勘探一些启示:它们间的基本地质特征、油气地质特征类似,且上三叠统地层为主要的烃源岩和自生自储组合,侏罗系储层也具有低孔、低渗、高含水饱和度、非均质性强的特征,裂缝对油气的富集、高产起到了重要作用。认为:加强砂体的展布、连通性研究,裂缝、断层性质、形态、沟通性、规模等研究,在有白垩系、第三系覆盖区完全有可能进行油气勘探。

关键词：对比分析地质条件上三叠统楚雄盆地四川盆地

Laser Cooling Using Anti-Stokes Fluorescence in Yb^(3+)-Doped Fluorozirconate Glasses

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Wuhan University Journal of Natural Sciences 2002年第2期7卷 177-181页

作者： Xu Tian-ming Li cheng-fang Zhou Xiao Zhong Jia-cheng School of Physics and Technology Wuhan UniversityWuhan 430072HubeiChina Infrared Material Institute Wuhan UniversityWuhan 430072HubeiChina

The fluorozirconate glasses ZBLANP( ZrF\-4-BaF\-2-LaF\-3-AlF\-3-NaF-PbF\-2) doped with different Yb\+ 3+ concentration were prepared. The Raman spectra and absorption spectra are measured to substantiate the existence of phonon-assisted emission. After analyzing the normalized absorption spectra of samples with different Yb\+ 3+-doped concentration, we calculated the maximum cooling effect in the 3 wt% Yb\+ 3+-doped sample pumped at 1 012.5 nm. The corresponding cooling capability is about -4.09 ℃/W and the cooling efficiency reaches 1.76%.

关键词： anti-Stokes fluorescence Yb^(3+)-doped ZBLANP glass cooling efficiency

顺-1,4-聚丁二烯的工艺性质——Ⅰ.钛盐催化聚合顺-1,4-聚丁二烯的性质

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高分子通讯 1963年第3期 110-122页

作者：李斌才刘亚东孙成芳张玉民中国科学院应用化学研究所

研究了用钛盐催化剂制备而具有不同分子量的顺-1,4-聚丁二烯的性貭。各种具有不同分子量的顺-1,4-聚丁二烯生胶的性貭很相似:（1）凝胶含量低于1％,（2）玻璃化温度在—110至—114℃之间,（3）顺-1,4结构含量在93至97％（表1A）。但门... 详细信息

研究了用钛盐催化剂制备而具有不同分子量的顺-1,4-聚丁二烯的性貭。各种具有不同分子量的顺-1,4-聚丁二烯生胶的性貭很相似:（1）凝胶含量低于1％,（2）玻璃化温度在—110至—114℃之间,（3）顺-1,4结构含量在93至97％（表1A）。但门尼粘度则随[η]值而激增（图1）。从生胶的应力-应变曲线可见各种顺-1,4-聚丁二烯样品在拉伸时并没有结晶现象（图2）。顺-1,4-聚丁二烯在滚筒上的加工性能对配炼温度极敏感。在25℃,40℃和60℃滚筒温度下的加炭黑配炼试验中,发现唯有在25℃下配炼才得到光滑的混合物,由此可制得抗张强度超过200公斤/厘米2的硫化物中,如果配炼系在40℃或60℃下进行,则顺-1,4-聚丁二烯趋向于破碎（图4）,得不到光滑的混合物,由此而制得的硫化物丧失抗张强度（图3）。根据下列试验结果:（1）将顺-1,4-聚丁二烯分别在25℃,40℃和60℃下进行素炼,在素炼过程中都不产生疑胶,无明显的降解（图6）,又素炼后链节结构并无变化（表3）;（2）温度对滚炼的影响是可逆的（表4）。我们认为,在40℃或60℃下配炼得到的硫化物之所以丧失抗张强度可能由于炭黑没有均匀分散。从合炭黑硫化物断面的显微镜照片亦可看到在25℃下配炼的硫化物确不同于在40℃和60℃下配炼者（图5A）。当含炭黑硫化物的定伸强度(M300％)超过60公斤/厘米2

关键词：聚丁二烯加工性能硫化物聚烯烃加工性质硫化合物生胶钛盐