检索结果-南通市图书馆

Conformal Ricci flow on asymptotically hyperbolic manifolds

在线全文

学校读者我要写书评

暂无评论

Science China Mathematics 2019年第1期62卷 157-170页

作者： Peng Lu jie Qing yu zheng Department of Mathematics University of Oregon Department of Mathematics University of California at Santa Cruz School of Mathematical Sciences East China Normal University

In this article, we study the short-time existence of conformal Ricci flow on asymptotically hyperbolic manifolds. We also prove a local Shi's type curvature derivative estimate for conformal Ricci flow.

关键词： conformal Ricci flow asymptotically hyperbolic manifolds short time existence local Shi's curvature derivative estimates

Effect of purification pretreatment on the recovery of magnetite from waste ferrous sulfate

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2016年第8期23卷 891-897页

作者： Wang yu Ying-lin Peng Ya-jie zheng School of Metallurgy and Environment Central South University School of Chemistry and Environmental Engineering Hunan City University

The present study was conducted to elucidate the influence of impurities in waste ferrous sulfate on its recovery of magnetite. Ferrous sulfate solution was purified by the addition of Na OH solution to precipitate impurities, and magnetite was recovered from ferrous sulfate solution without and with purification pretreatment. Calcium hydroxide was added to the solution of ferrous sulfate as a precipitator. A mixed product of magnetite and gypsum was subsequently obtained by air oxidation and heating. Wet-milling was performed prior to magnetic separation to recover magnetite from the mixed products. The results show that with the purification pretreatment, the grade of iron in magnetite concentrate increased from 62.05% to 65.58% and the recovery rate of iron decreased from 85.35% to 80.35%. The purification pretreatment reduced the conglutination between magnetite and gypsum, which favors their subsequent magnetic separation. In summary, a higher-grade magnetite with a better crystallinity and a larger particle size of 2.35 μm was obtained with the purification pretreatment.

关键词： ferrous sulfate titanium dioxide purification magnetite magnetic separation

应对供应中断风险下消费者恐慌囤货行为:涨价策略与限购策略

在线全文

学校读者我要写书评

暂无评论

管理工程学报 2025年第2期39卷 118-129页

作者：郑锐王宇鲍丽娜武汉理工大学安全科学与应急管理学院湖北武汉430070 武汉理工大学中国应急管理研究中心湖北武汉430070 浙江大学管理学院浙江杭州310058

本文研究了零售商应对供应中断风险下消费者恐慌囤货行为的涨价策略与限购策略。研究模型考虑一个垄断零售商在两个订货周期内向市场销售一种生活必需品,第二期的供应中断风险可能导致消费者在第一期发生恐慌囤货。研究基于对消费者恐... 详细信息

本文研究了零售商应对供应中断风险下消费者恐慌囤货行为的涨价策略与限购策略。研究模型考虑一个垄断零售商在两个订货周期内向市场销售一种生活必需品,第二期的供应中断风险可能导致消费者在第一期发生恐慌囤货。研究基于对消费者恐慌囤货决策模型的刻画,分析了消费者恐慌囤货行为如何影响零售商利润以及社会总福利,然后进一步分析了零售商分别在什么条件下应采取涨价策略或限购策略以及这些策略将如何影响社会总福利。研究结果表明:(1)当零售商拥有足够的库存时,一定程度的恐慌囤货可以增加零售商利润和社会总福利;而当恐慌囤货导致零售商严重缺货时,恐慌囤货将损害零售商利润和社会总福利。(2)当零售商需要采取策略应对消费者恐慌囤货行为时,存在一个消费者恐慌强度的阈值,当恐慌强度低于阈值时,零售商应采取涨价策略调节消费者的囤货需求;当恐慌强度高于阈值时,零售商应采取限购策略限制消费者的囤货。(3)零售商不同的应对策略对社会总福利有不同的影响,当恐慌强度非常高时,采取限购策略可以显著改善社会总福利;采取涨价策略可以提高零售商的备货动机,在一定条件下可以改善社会总福利。

关键词：供应链管理供应中断风险恐慌囤货需求管理限购策略

Effects of Thermal Gradients and Rotational Flows on Grain Growth in 22 t Steel Ingots

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2016年第9期23卷 973-980页

作者： zheng CHEN Qi-jie ZHAI jie-yu ZHANG Hong-gang ZHONG State Key Laboratory of Advanced Special Steel School of Materials Science and EngineeringShanghai University Mechanical Department Tongling University

Heavy ingots are widely used in many industrial fields. The coarse grains formed during the process of in- got solidification influence the properties and fracture behaviors of the final products. The coarse grain growth was simulated under different thermal gradients. A 30Cr2Ni4MoV steel ingot was melted in a cubic crucible with dimen-sions of 15 cm×10 cm×23 cm, and the cooling conditions on each side of the crucible were controlled by different thermal curves. The influences of thermal gradients and rotational flows on grain growth in heavy steel ingots were then investigated both numerically and experimentally. The results showed that when the amplitude of the rotation angle was 60°, the metal was solidified under a reciprocating horizontal rotational condition when the angular velocity was 10 （°）/s or 20 （°）/s. As the thermal gradient increased, the lengths of the primary columnar grains in- creased, and the diameters of equiaxed grains decreased. When the direction of flow rotation was perpendicular to the direction of grain growth, the columnar grain zone was nearly eliminated, and the average diameter of equiaxed grains was 0.5 mm.

关键词： heavy ingot thermal simulation method thermal gradient rotational flow grain refinement

Coseismic surface ruptures of MW7.8 and MW7.5 earthquakes occurred on February 6, 2023, and seismic hazard assessment of the East Anatolian Fault Zone, Southeastern Türkiye

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年

作者： Peng LIANG yueren XU Xiaocheng ZHOU Ying LI Qinjian TIAN Huiping ZHANG Zhikun REN Jingxing yu Chuanyou LI zheng GONG Shiguang WANG Aixia DOU Zifa MA Junjie LI Key Laboratory of Earthquake Prediction Institute of Earthquake ForecastingChina Earthquake Administration China Earthquake Disaster Prevention Center State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake Administration Institute of Geophysics China Earthquake Administration

On February 6, 2023, southeastern Türkiye experienced a devastating earthquake doublet along the East Anatolian Fault（EAF）, with moment magnitude（MW） values of 7.8 and 7.5. These strong earthquakes resulted in at least 50,000 deaths and severe economic losses. Systematic research on coseismic surface ruptures induced by these events is vital for assessing the cascade rupture behaviors of plate boundary faults and future seismic hazards in the region. Interpretation of high-resolution post-earthquake satellite images and field investigations yielded the following results:（1） the two strong earthquakes had separate rupture zones. The first earthquake generated an approximately 280 km coseismic surface rupture along the southwestern segment of the main EAF, with 241 left-lateral displacements reaching up to 6.8±0.68 m, particularly 40 km northeast of the epicenter. The second earthquake produced a roughly 110 km surface rupture on an east-west branch of the EAF, with maximum displacements of 7.2±0.72 m.（2） The MW7.8 earthquake resulted in a cascading rupture across multiple segments of the southwestern section of the main EAF, with significantly variable displacements. The northeastern and southwestern parts of the main EAF and Malatya Fault remain at risk of strong earthquakes in the future.（3） The EAF rupture zone is densely populated, and due to the site amplification effect of loose sediments on foreland alluvial fans, foundation failures of buildings in the populated areas are common. Therefore, it is crucial to enhance the future seismic fortification capabilities in urban and rural areas along the EAF.

关键词：

人源性抗血小板膜糖蛋白Ⅱb/Ⅲa Fab噬菌体抗体库的筛选与鉴定

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

苏州大学学报（医学版） 2008年第5期28卷 696-698,732页

作者：崔宇杰董宁征庞爱明白霞阮长耿苏州大学附属第一医院江苏省血液研究所江苏苏州215006

目的从已构建的人源性抗血小板膜糖蛋白(glycoprotein,GP)Ⅱb/ⅢaFab噬菌体抗体库中筛选人源性抗血小板膜GPⅡb/ⅢaFab抗体,并对特异性阳性克隆进行鉴定。方法以表达GPⅡb/Ⅲa的CHO123细胞包板,对人源性抗血小板膜GPⅡb/ⅢaFab噬菌体抗... 详细信息

目的从已构建的人源性抗血小板膜糖蛋白(glycoprotein,GP)Ⅱb/ⅢaFab噬菌体抗体库中筛选人源性抗血小板膜GPⅡb/ⅢaFab抗体,并对特异性阳性克隆进行鉴定。方法以表达GPⅡb/Ⅲa的CHO123细胞包板,对人源性抗血小板膜GPⅡb/ⅢaFab噬菌体抗体库进行富集筛选,采用细胞ELISA法筛选特异性阳性克隆,用Western blot法鉴定表达蛋白与GPⅡb/Ⅲa结合的特异性,将阳性克隆进行扩增、测序。结果以CHO123细胞富集淘筛3轮,并用ELISA法检测到2个高亲合力的特异性识别血小板膜GPⅡb/Ⅲa的克隆,Westernblot鉴定结果显示在阳性克隆的培养上清和细菌冻融上清均有特异性条带出现。对核苷酸序列进行同源性分析,证实这两个克隆轻链基因与人免疫球蛋白κ轻链的同源性分别高达97%和98%,重链基因与人免疫球蛋白Fd段的同源性分别高达94%和93%。结论利用噬菌体抗体库技术,成功地从人源性抗血小板膜GPⅡb/ⅢaFab抗体库中筛选出抗血小板膜GPⅡb/Ⅲa的特异性阳性克隆,该克隆具有较高的特异性,其克隆基因符合抗体可变区结构特点。

关键词：血小板膜糖蛋白 Ⅱb/Ⅲa 噬菌体抗体库筛选鉴定

基于光捕获效应的Ti3C2Tx/硅纳米线异质结光电探测器

在线全文

学校读者我要写书评

暂无评论

科学技术创新 2025年第1期 17-20页

作者：喻杰合肥工业大学安徽合肥

通过金属辅助化学刻蚀法制备了硅纳米线(Si NWs),使用最小强化层脱层刻蚀技术分离了Ti_(3)C_(2)Tx纳米片,随后构筑了Ti_(3)C_(2)Tx/Si NWs异质结光电探测器。利用扫描电子显微镜对Ti_(3)C_(2)Tx/Si NWs的形貌进行分析,采用X射线衍射仪... 详细信息

通过金属辅助化学刻蚀法制备了硅纳米线(Si NWs),使用最小强化层脱层刻蚀技术分离了Ti_(3)C_(2)Tx纳米片,随后构筑了Ti_(3)C_(2)Tx/Si NWs异质结光电探测器。利用扫描电子显微镜对Ti_(3)C_(2)Tx/Si NWs的形貌进行分析,采用X射线衍射仪分析了Ti_(3)C_(2)Tx的结构。器件分析表明,该器件呈现出宽带响应特性,在920 nm处具有约526 mA/W的峰值响应度,其响应相较于平面硅器件有了很大的提升。这种光电特性与Si NWs中的光捕获效应有关。这些结果表明,Si NWs是未来高性能硅基光电探测器的潜在构建模块。

关键词：硅纳米线光电探测器光捕获效应

Energy equalizing routing for fast data gathering in wireless sensor networks

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2007年第4期14卷 13-21页

作者： zheng jie GUO Shu-jie QU yu-gui ZHAO Bao-hua Department of Electronic Engineering and Information Science Universityof Science and Technology of China Hefei 230027 China Department of Computer University of Science and Technology of ChinaHefei 230027 China

Energy saving and fast responding of data gathering are two crucial factors for the performance of wireless sensor networks. A dynamic tree based energy equalizing routing scheme （DTEER） was proposed to make an effort to gather data along with low energy consumption and low time delay. DTEER introduces a dynamic multi-hop route selecting scheme based on weight-value and height-value to form a dynamic tree and a mechanism similar to token passing to elect the root of the tree. DTEER can simply and rapidly organize all the nodes with low overhead and is robust enough to the topology changes. When compared with power-efficient gathering in sensor information systems （PEGASIS） and the hybrid, energy- efficient, distributed clustering approach （HEED）, the simulation results show that DTEER achieves its intention of consuming less energy, equalizing the energy consumption of all the nodes, alleviating the data gathering delay, as well as extending the network lifetime perfectly.

关键词： wireless sensor networks energy equalizing,dynamic tree fast data gathering delay

Analysis of genetic diversity and prediction of Larix species distribution in the Qinghai–Tibet Plateau,China

在线全文

学校读者我要写书评

暂无评论

Journal of Forestry Research 2023年第3期34卷 705-715页

作者： Qiqiang Guo Huie Li Weilie zheng Jinwen Pan jie Lu Jiangrong Li yu zheng Institute for Forest Resources&Environment of Guizhou Key Laboratory of Forest Cultivation in Plateau Mountain of Guizhou ProvinceGuizhou UniversityGuiyang 550025People’s Republic of China College of Forestry Guizhou UniversityGuiyang 550025People’s Republic of China College of Agriculture Guizhou UniversityGuiyang 550025People’s Republic of China Institute of Tibet Plateau Ecology Tibet Agriculture and Animal Husbandry UniversityNyingchi Tibet 860000People’s Republic of China Key Laboratory of Forest Ecology in Tibet Plateau(Tibet Agriculture and Animal Husbandry University) Ministry of EducationNyingchi Tibet 860000People’s Republic of China Plant Research Center Chengdu Botanical GardenChengdu 610083People’s Republic of China

Larix resources in the Qinghai-Tibet Plateau have important ecological and economic ***,the lack of genetic diversity background and related research hinders the development of conservation *** this study,genetic diversity and distribution of fi ve Larix species were *** 19 polymorphic microsatellite markers to study 272 representative individuals from 13 populations,the results show low genetic diversity at the population level,with variation explained mainly by diff erentiation among *** Larix populations were classifi ed into two clades,one formed by eight populations,including three of the species in this study,***,***,and *** *** other clade consists of fi ve populations,including the other two species in this study,*** thii and *** distance of the species was aff ected by geographical isolation and genetic diversity was mainly aff ected by *** area suitable for Larix *** during the Last Glacial Maximum compared to the current distribution according to the niche model,but should increase in future climate scenarios(2050s),expanding westward along the *** results provide an important scientifi c basis for the development of conservation strategies and further the sustainable utilization of Larix resources in the Qinghai-Tibet Plateau.

关键词： Larix spp. Genetic diversity Phylogenetic relationship Genetic structure Ecological niche modeling Qinghai-Tibet Plateau