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Synthesis and characterization of Ca0.9Mg0.1TiO3：Pr3＋,Ag＋ phosphor

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Journal of Rare Earths 2018年第2期36卷 125-129页

作者： Rui chen donghua chen College of Chemistry and Chemical Engineering Yunnan Normal University Kunming 650500 China Hubei Key Laboratory for Catalysis and Material Science College of Chemistry and Material Science South Central University for Nationalities Wuhan 430074 China

Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋）,Ag~＋ phosphors were synthesized by solid-state reaction technique. The crystalline phase and luminescence performances of Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋）,Ag~＋ were observed by X-ray powder diffractometer（XRD）, transmission electron microscope（TEM）, photoluminescence spectrometer and brightness meter, respectively. The addition of Ag~＋ can diminish in the crystal particle sizes of Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋）. Because Ag＋ can reduce the concentration of the undesirable defects in the phosphor, luminescence intensity of Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋）,Ag~＋ is 2.3 times as high as that of Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋）at the same preparation condition. The effect of Ag＋ on the persistent afterglow properties is to deepen the energy storage traps and enhance the energy transfer efficiency from Ca_（0.9）Mg_（0.1）TiO_3 to Pr^（3＋）. The persistent afterglow properties of Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋）,Ag~＋ are better than those of Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋） at the same preparation condition. In conclusion,Ca_（0.9）Mg_（0.1）TiO_3：Pr^（3＋）,Ag~＋ phosphor with molar ratio of Ag~＋to Pr^（3＋） 3：1 obtained at 900 ℃ for 4 h exhibits the optimal photoluminescence performances.

关键词： Phosphor Transmission electron microscope Lumine scence X-ray diffraction Afterglow Rare earths

Mobile channel estimation for MU-MIMO systems using KL expansion based extrapolation

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Journal of Systems Engineering and Electronics 2012年第3期23卷 349-354页

作者： donghua chen Hongbing Qiu College of Information Science and Engineering Huaqiao UniversityXiamen 361021E R.China Information and Communication College Guilin University of Electronic TechnologyGuilin 541004P.R.China

In multi-user multiple input multiple output （MU-MIMO） systems, the outdated channel state information at the transmit- ter caused by channel time variation has been shown to greatly reduce the achievable ergodic sum capacity. A simple yet effec- tive solution to this problem is presented by designing a channel extrapolator relying on Karhunen-Loeve （KL） expansion of time- varying channels. In this scheme, channel estimation is done at the base station （BS） rather than at the user terminal （UT）, which thereby dispenses the channel parameters feedback from the UT to the BS. Moreover, the inherent channel correlation and the parsimonious parameterization properties of the KL expan- sion are respectively exploited to reduce the channel mismatch error and the computational complexity. Simulations show that the presented scheme outperforms conventional schemes in terms of both channel estimation mean square error （MSE） and ergodic capacity.

关键词： channel estimation multiple input multiple output (MIMO) Karhunen-Loeve (KL) expansion minimum mean square error (MMSE).

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供应链社会资本对供应链韧性的影响研究

中国商论 2024年第18期33卷 19-22页

作者：缪卓奇陈东华浙江万里学院物流与电子商务学院浙江宁波315100

供应链韧性是企业在复杂多变的环境中,应对挑战并抓住机遇的关键所在。本文基于资源基础观和动态能力理论,分析上游供应链社会资本对供应链韧性的直接作用以及供应链外部整合在此过程中的中介作用,并对环境包容性的调节效应进行检验。... 详细信息

供应链韧性是企业在复杂多变的环境中,应对挑战并抓住机遇的关键所在。本文基于资源基础观和动态能力理论,分析上游供应链社会资本对供应链韧性的直接作用以及供应链外部整合在此过程中的中介作用,并对环境包容性的调节效应进行检验。本文基于327份浙江省汽车制造企业问卷调查数据的检验结果显示:(1)上游供应链的结构资本与关系资本均对供应链韧性起到正向的影响作用。(2)供应链外部整合在供应链社会资本与供应链韧性之间的关系起到中介作用。(3)环境包容性负向调节供应链社会资本与供应链外部整合之间的关系。本文拓展了关于上游社会资本如何影响企业供应链韧性的理论研究,同时也为汽车制造企业如何有效提升供应链韧性提供了新的对策思路。

关键词：供应链韧性供应链社会资本层次回归分析供应链外部整合环境包容性

基于BIM技术的叠合板深化设计工具开发与应用研究

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广东土木与建筑 2024年第4期31卷 1-5页

作者：周明谭伟健陈东华刘晨广东省建科建筑设计院有限公司广州510500

随着中国建筑产业的转型升级,装配式建筑在建筑业转型中得到了快速发展。然而,装配式构件深化设计效率低下的问题制约了装配式建筑的发展。为了解决这个问题,提出了一种基于BIM技术的装配式叠合板构件深化设计方法,并以此为基础开发出... 详细信息

随着中国建筑产业的转型升级,装配式建筑在建筑业转型中得到了快速发展。然而,装配式构件深化设计效率低下的问题制约了装配式建筑的发展。为了解决这个问题,提出了一种基于BIM技术的装配式叠合板构件深化设计方法,并以此为基础开发出相应的叠合板深化设计程序。该程序解决了构件拆分、构件配筋、构件出图等流程的设计问题。程序应用于实际工程项目中,验证了深化设计方法和设计程序应用于叠合板构件深化设计的可行性。结果表明,该程序能够提高设计工作效率,降低设计过程中的人为失误率。因此,通过这种方法将有助于推动装配式建筑的发展,提升设计精度。

关键词： BIM 装配式建筑叠合板深化设计

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一种基于无线供能的物联网双向传输方案

信息技术与信息化 2024年第5期 123-128页

作者：陶迅洲陈东华邵凯淮北师范大学物理与电子信息学院安徽淮北235000

针对物联网(IoT)终端节点能量受限以及双向通信上下行服务质量(QoS)不对称的问题,在功分(PS)和时分(TS)两种通信协议的基础上,提出了一种基于无线供能的时变时分双工(TDD)传输方案。方案以最小化系统功率为目标,每个节点都在双向通信速... 详细信息

针对物联网(IoT)终端节点能量受限以及双向通信上下行服务质量(QoS)不对称的问题,在功分(PS)和时分(TS)两种通信协议的基础上,提出了一种基于无线供能的时变时分双工(TDD)传输方案。方案以最小化系统功率为目标,每个节点都在双向通信速率和能量采集的约束下提高了系统传输效率。为了求解优化问题,采用半定松弛(SDP)和一阶泰勒近似将原始非凸问题转化为凸问题,进而通过连续凸逼近(SCA)迭代算法获得优化问题最优解。仿真表明,所提出的传输方案不仅在物理上可行,而且相对于固定分配传输时间的方案,有效地降低了系统的发射功耗。

关键词：能量采集时分多址波束形成双向通信凸优化

Worst-case robust energy harvesting maximization in cellular networks

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Science China(Information Sciences) 2018年第8期61卷 240-242页

作者： donghua chen Yucheng HE Lin ZHOU Rui ZHAO Xiamen Key Laboratory of Mobile Multimedia Communications College of Information Science and EngineeringHuaqiao University

Dear editor,Wireless energy harvesting(EH)is considered as a promising approach to achieve power selfsustainability in energy restricted *** literature,most studies on wireless EH communications focused on the design ... 详细信息

关键词： IR MS CSI Worst-case robust energy harvesting maximization in cellular networks

In-situ green synthesis of highly active GSH-capped Pt–Au–Ag-hybrid nanoclusters

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Science China Chemistry 2014年第11期57卷 1532-1537页

作者： chen donghua GAO ShengPing UR REHMAN Fawad JIANG Hui WANG XueMei School of Chemistry and Chemical Engineering Southeast University State Key Laboratory of Bioelectronics (Chien-Shiung Wu Lab) School of Biological Science and Medical EngineeringSoutheast University

Recently much attention has been paid to the application of metal hybrid nanoparticles in industrial catalytic fields because of their super-efficient catalytic activity and attractive properties. We explored a novel strategy to prepare GSH-capped Pt–Au–Ag-hybrid nanoclusters through the synergistic effect between ascorbic acid(VC) and glutathione(GSH) with chloroplatinic acid, chloroauric acid, and silver nitrate as precursors. The potential utilization of as-prepared GSH-capped Pt–Au–Aghybrid nanoclusters for catalytic applications has been evaluated through the reduction of 4-nitrophenol(4-NP) with NaBH4; we obtained the kinetic data by monitoring with UV-Vis spectroscopy. Our results illustrate that GSH-capped Pt–Au– Ag-hybrid nanoclusters could facilitate the process of reduction of 4-NP in a way that is unprecedented. This approach may offer a novel, non-cytotoxicity, efficient catalyst for industry.

关键词： Pt–Au–Ag-hybrid ascorbic acid glutathione 4-nitrophenol catalyst

Quantitative distinction of the relative actions of climate change and human activities on vegetation evolution in the Yellow River Basin of China during 1981-2019

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Journal of Arid Land 2023年第1期15卷 91-108页

作者： LIU Yifeng GUO Bing LU Miao ZANG Wenqian YU Tao chen donghua School of Civil Architectural Engineering Shandong University of TechnologyZibo 255000China Key Laboratory of Urban Land Resources Monitoring and Simulation Ministry of Natural ResourcesShenzhen 518000China Key Laboratory of National Geographic Census and Monitoring Ministry of Natural ResourcesWuhan 430072China Aerospace Information Research Institute Chinese Academy of SciencesBeijing 100101China State Key Laboratory of Resources and Environmental Information System Institute of Geographic Sciences and Natural Resources ResearchChinese Academy of SciencesBeijing 100101China Key Laboratory of Agricultural Remote Sensing Ministry of Agriculture and Rural Affairs/Institute of Agricultural Resources and Regional PlanningChinese Academy of Agricultural SciencesBeijing 100081China Zhongke Langfang Institute of Spatial Information Applications Langfang 065000China College of Computer and Information Engineering Chuzhou UniversityChuzhou 239000China

Under the combined influence of climate change and human activities,vegetation ecosystem has undergone profound *** can be seen that there are obvious differences in the evolution patterns and driving mechanisms of vegetation ecosystem in different historical ***,it is urgent to identify and reveal the dominant factors and their contribution rates in the vegetation change *** on the data of climate elements(sunshine hours,precipitation and temperature),human activities(population intensity and GDP intensity)and other natural factors(altitude,slope and aspect),this study explored the spatial and temporal evolution patterns of vegetation NDVI in the Yellow River Basin of China from 1989 to 2019 through a residual method,a trend analysis,and a gravity center model,and quantitatively distinguished the relative actions of climate change and human activities on vegetation evolution based on Geodetector *** results showed that the spatial distribution of vegetation NDVI in the Yellow River Basin showed a decreasing trend from southeast to *** 1981-2019,the temporal variation of vegetation NDVI showed an overall increasing *** gravity centers of average vegetation NDVI during the study period was distributed in Zhenyuan County,Gansu Province,and the center moved northeastwards from 1981 to *** 1981-2000 and 2001-2019,the proportion of vegetation restoration areas promoted by the combined action of climate change and human activities was the *** the study period(1981-2019),the dominant factors influencing vegetation NDVI shifted from natural factors to human *** results could provide decision support for the protection and restoration of vegetation ecosystem in the Yellow River Basin.

关键词： vegetation evolution driving mechanisms climate change human activities relative actions Geodetector Yellow River Basin

Large Shareholder Tunneling and Risk of Stock Price Crash： Evidence from China

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Frontiers of Business Research in China 2014年第2期8卷 154-181页

作者： Yongjian Shen Dequan Jiang donghua chen School of Accounting Nanjing University of Finance and Economics Nanjing 210046 China School of Business Nanjing University Nanjing 210093 China

Although several studies have examined the economic consequences of large shareholders＇ tunneling behavior, little attention has been paid to the negative effects of tunneling on firms＇ extreme events. In this article, we investigate how tunneling behavior affects firm-level stock price crashes. The findings indicate that the probability of stock price crashes is positively associated with the extent of tunneling behavior by large shareholders. The positive relationship is more pronounced after the split of share structure reform and is moderated by the firm＇s financial conditions. This study contributes to the emerging body of literature focusing on the economic consequences of tunneling and stock price crashes. The conclusions drawn from the study also provide a frame of reference for investor protection and investment portfolios based on large shareholders＇ tunneling behavior in China.

关键词： large shareholder tunneling behavior risk of stock price crash investor protection