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Journal of Environmental Sciences 2017年第5期29卷 206-213页

作者： Guangke Li junyan chen Wei Yan Nan Sang College of Environment and Resource Shanxi University Taiyuan 030006 China

To compare the toxicity of landfill leachate exposure at the early stages of seed soaking and germination on maize,a field experiment was conducted to evaluate the physiological aspects of growth,yield and potential clastogenicity of root-tip cells. The maizes were treated with leachate at levels of 2%,10%,20%,30% or 50%（V/V）. First,the change of physiological indexes,including chlorophyll（Chl）,Malondialdehyde（MDA）and Reactive oxygen species（ROS）levels,combined with yield all showed that soaking with leachate,but not germination,generated a greater ecological risk on maize. After a soaking treatment of maize with 50% leachate,the Chl,MDA and ROS levels during a vigorous growth period were 47.3%,149.8% and 309.7%,respectively,of the control,whereas the yield decreased to 68.6% of the control. In addition,our results demonstrated that the leachate at lower levels could promote growth. This is mainly embodied in that the yield of maize treated with 10%leachate at the soaking stage increased to 116.0% of the control. Moreover,the cytological analysis experiment also demonstrated that the ecological risk of leachate still exists in both cases. Furthermore,the gray relational analysis showed that the ear row number and tassel branch number were the major factors affecting the yield of maize treated with 50%leachate at the stages of soaking and germination,respectively. In general,these results are helpful in understanding the phytotoxicity of leachate,which provides additional reference data for risk assessment and management of leachate.

关键词： Landfill leachate Maize Phytotoxicity Seed soaking Germination

Diastereodivergent[4+2]annulation of biphenylenes with enones via nickel(0)-catalyzed C-C bond activation

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Chinese Chemical Letters 2022年第12期33卷 5056-5060页

作者： junyan chen Dachang Bai Xiuli Guo Yiyao Wang Xingwei Li NMPA Key Laboratory for Research and Evaluation of Innovative Drug Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine ChemicalsKey Laboratory of Green Chemical Media and ReactionsMinistry of EducationSchool of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiang 453007China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China School of Chemistry and Chemical Engineering Shaanxi Normal University(SNNU)Xi'an 710062China

Ni(0)-catalyzed regio-and diastereodivergent[4+2]annulation of biphenylenes withα,βunsaturated ketones is *** solvent-controlled diastereodivergent reaction integrates C-C bond cleavage of biphenylene and C=C double bond insertion selectivity,offering a mild approach to all possible diastereoisomers of 9,10-dihydrophenanthrene derivatives from the same starting materials.

关键词： Nickel Enones Biphenylenes Diastereodivergent annulation C-C activation 9,10-Dihydrophenanthrenes

Catalytic[3+3]Annulation ofβ-Ketoethers and Cyclopropenones via C(sp^(3))-O/C-C Bond Cleavage under Transition-Metal Free Conditions

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Chinese Journal of Chemistry 2021年第10期39卷 2769-2773页

作者： Dachang Bai junyan chen Bingbing Zheng Xueyan Li Junbiao Chang NMPA Key Laboratory for Research and Evaluation of Innovative Drug Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine ChemicalsSchool of Chemistry and Chemical EngineeringHenan Normal UniversityXinxiangHenan453007 China State Key Laboratory of Organometallic Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Main observation and conclusion The efficient cleavage of carbon-oxygen(C—O)bond is highly important for the transformation of oxygen-rich biomass and industry ***,an efficient[3+3]annulation ofβ-ketoethers with cyclopropenones in the presence of catalytic base has been developed,which proceeds through the C(sp^(3))—O bonds cleavage inβ-ketoethers and C—C bond cleavage in cyclopropenones under transition-metal free *** cleavage of C(sp^(3))—O bonds in alkyl alkyl ethers and aryl alkyl ethers was *** reaction featured excellent functional group compatibility and chemoselectivity,affording various 2-pyrones in good to excellent yields under mild conditions and simple operation.

关键词： C-O/C-C activation [3+3]Annulation β-Ketoethers Cyclopropenones Transition-metal free conditions

Mongolia Contributed More than 42%of the Dust Concentrations in Northern China in March and April 2023

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Advances in Atmospheric Sciences 2023年第9期40卷 1549-1557页

作者： Siyu chen Dan ZHAO Jianping HUANG Jiaqi HE Yu chen junyan chen Hongru BI Gaotong LOU Shikang DU Yue ZHANG Fan YANG Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou UniversityLanzhou 730000China Institute of Desert Meteorology China Meteorological AdministrationUrumqi 830002China

Dust storms are one of the most frequent meteorological disasters in China,endangering agricultural production,transportation,air quality,and the safety of people’s lives and *** the backdrop of climate change,Mongolia’s contribution to China’s dust cannot be ignored in recent *** this study,we used the Weather Research and Forecasting model coupled with Chemistry(WRF-Chem),along with dynamic dust sources and the HYSPLIT model,to analyze the contributions of different dust sources to dust concentrations in northern China in March and April *** results show that the frequency of dust storms in 2023 was the highest observed in the past *** and the Taklimakan Desert were identified as two main dust sources contributing to northern ***,Mongolia contributed more than 42%of dust,while the Taklimakan Desert accounted for 26%.A cold high-pressure center,a cold front,and a Mongolian cyclone resulted in the transport of dust aerosols from Mongolia and the Taklimakan Desert to northern China,where they affected most parts of the ***,two machine learning methods[the XGBoost algorithm and the Synthetic Minority Oversampling Technique(SMOTE)]were used to forecast the dust storms in March 2023,based on ground observations and WRF-Chem simulations over East ***-SMOTE performed well in predicting hourly PM10 concentrations in China in March 2023,with a mean absolute error of 33.8μg m−3 and RMSE of 54.2μg m−3.

关键词： dust aerosol Mongolian dust transboundary contribution WRF-Chem HYSPLIT model

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冷热联供系统的能耗估算

暖通空调 2001年第3期31卷 12-15页

作者：陈君燕清华大学

阐述了利用热电联产热、锅炉房供热和废热驱动的各种冷热联供系统的能耗估算方法。对热电联产情况考虑了汽轮机进排气参数等条件的变化对供热供冷能耗的影响。给出了一定条件下各种系统包括热泵系统的供热供冷一次能耗率。

关键词：供热供冷热电联产能耗

Post-operative venous thromboembolism in patients after extracranial otologic surgery: A case series

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Journal of Otology 2024年第2期19卷 59-62页

作者： Davit Mazmanyan Rongrong Zhu Juanjuan Gao Yu Yang Jiake Zhong junyan chen Haijin Yi Weiwei Wu Department of Vascular Surgery Beijing Tsinghua Changgung HospitalSchool of Clinical MedicineTsinghua UniversityBeijing102218China Department of Otolaryngology Head&Neck SurgeryBeijing Tsinghua Changgung HospitalSchool of Clinical MedicineTsinghua UniversityBeijing102218China

Objective:This study aimed to report 9 venous thromboembolism(VTE)cases after extracranial otologic surgery and analyze the potential risk *** design:Case ***:Single tertiary-level academic ***:Totally,9 cases of VTE were identified among adults who underwent extracranial otologic surgery at our hospital from January 2018 to December *** risk scores were calculated,and comprehensive preoperative,operative,and postoperative clinical data within 14 days were collected to assess the evidence of ***:The median age of 9 patients was 64 years *** them,7(77.8%)patients presented with intramuscular vein thrombosis,1(11.1%)patient had deep vein thrombosis,and 1(11.1%)patient experienced pulmonary ***,8(88.9%)patients had low or middle Caprini risk scores(≤4)with an average of 2.67±0.47 *** average Caprini scores for all patients were 4.44±0.35 on postoperative day(POD)1 and 5.67±0.64 on POD14.D-dimer levels were collected,indicating an average of 0.55±0.17 mg/FEU preoperatively,8.53±3.94 mg/FEU at day 1,and 3.76±0.45 mg/FEU at *** postoperative period,7(77.8%)patients experienced vertigo/dizziness and/or head immobility/bed ***:The present study highlighted that patients with low-and middle-risk of VTE undergoing otologic surgery should be also vigilant about postoperative ***/dizziness and/or head immobility/bed rest in postoperative period should be considered as minor risk factors for developing VTE in patients undergoing extracranial otologic *** perioperative assessments,including Caprini risk score evaluation,Ddimer testing,and venous ultrasound of lower extremities,is recommended to ensure patients’safety.

关键词： Venous thromboembolism(VTE) Extracranial otologic surgery Caprini risk score D-dimer level

Research on the evaluation model of the modernization level of urban construction in Jiangsu Province,China

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Science China(Technological Sciences) 2010年第9期53卷 2510-2514页

作者： YANG junyan1 & chen Wen2 1 School of Architecture,Southeast University,Nanjing 210096,China 2 Nanjing Institute of Geography and Limnology,Chinese Academy of Sciences,Nanjing 210008,China School of Architecture Southeast University Nanjing China Nanjing Institute of Geography and Limnology Chinese Academy of Sciences Nanjing China

The modernization of urban construction is a key index in the process of urbanization,and also is an important index to measure the level of socio-economic and cultural *** paper analyzes and explores the related concepts of modernization of urban construction,analyzes the situation and identity of urban construction layer by layer so as to establish an evaluation index system of the modernization level of urban construction and then the paper evaluates the modernization level of urban construction from four different angles,which are the perspectives of the urban planning control,the level of urban facilities,urban management,urban construction *** later analyzes the evaluation results by choosing Jiangsu Province as a research hierarchy from the scale chains of urban study and makes efforts to the operative and directive development direction.

关键词： modernization of urban construction index system evaluation model

静电场作用下介电球形液滴的蒸气压及平衡半径

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华南理工大学学报（自然科学版） 2023年第2期51卷 131-136页

作者：韩光泽陈俊岩华南理工大学物理与光电学院广东广州510640

液滴的凝结与蒸发是一种相变过程,它既是一种高效的传热传质过程,又与环境气候变化密切相关。实验表明,静电场对液滴的形成过程有重要的影响,是一种有效的强化传热传质方式,也与雷电雨的形成有关。本文基于相平衡理论,利用电场作用下的... 详细信息

液滴的凝结与蒸发是一种相变过程,它既是一种高效的传热传质过程,又与环境气候变化密切相关。实验表明,静电场对液滴的形成过程有重要的影响,是一种有效的强化传热传质方式,也与雷电雨的形成有关。本文基于相平衡理论,利用电场作用下的热力学方程导出了静电场作用下球形介电液滴内外的压强差、蒸气压以及液滴平衡半径的数学表达式。采用数值计算的方法,利用该数学表达式对液滴的形成过程进行了分析。结果表明,与没有电场作用相比,静电场作用下介电液滴内外的压强差、蒸气压以及平衡半径都有增加。蒸气压和平衡半径增加将加速液滴的蒸发过程,因此静电场作用能够促使液滴的快速蒸发。该结论与实验相符,可为相关的理论研究及工程应用提供参考。

关键词：静电场介电球形液滴内外压强差蒸气压平衡半径

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美国地基反卫星激光武器发展分析

红外与激光工程 2020年第S1期49卷 42-47页

作者：陈军燕廖龙文曾鹏西北核技术研究所陕西西安710024

为争夺太空控制权,先进国家开展了广泛的反卫星激光武器的研制,并初步具备反卫星能力。尤其以地基激光反卫武器为主的定向能武器,可对在轨卫星等目标进行软、硬破坏,其技术发展最为成熟,已成为未来外空攻防作战武器系统的重要发展方向,... 详细信息

为争夺太空控制权,先进国家开展了广泛的反卫星激光武器的研制,并初步具备反卫星能力。尤其以地基激光反卫武器为主的定向能武器,可对在轨卫星等目标进行软、硬破坏,其技术发展最为成熟,已成为未来外空攻防作战武器系统的重要发展方向,受到世界各国的高度重视。从地基反卫星角度出发,重点对公开披露的美国地基反卫星激光系统进行了介绍和分析,介绍了地基反卫星激光系统的基本概念、操作概念、关键组成、试验模式和打击模式,对该系统涉及的关键性能参数进行了分析,为研究美国可能的地基反卫星激光武器装备和卫星目标防激光打击提供参考。

关键词：激光武器反卫星地基激光系统激光传输

PERMANENCE OF GENERAL NONAUTONOMOUS SINGLE-SPECIES KOLMOGOROV TYPE SYSTEM WITH DELAY AND FEEDBACK CONTROLS

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Annals of Differential Equations 2009年第4期25卷 379-384页

作者： Lijuan chen, junyan Xu (College of Math. and Computer Science, Fuzhou University, Fuzhou 350002)

In this paper, we consider the general nonautonomous single-species Kolmogorov type system with delay and feedback controls. Sufficient conditions for the permanence of species are established. Our results generalize ... 详细信息

关键词： Kolmogorov system permanence delay feedback controls