检索结果-南通市图书馆

Light-induced magnetic phase transition in van der Waals antiferromagnets

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Science China(Physics,Mechanics & Astronomy) 2023年第7期66卷 136-141页

作者： Jiabin Chen Yang Li Hongyu Yu Yali Yang heng jin Bing Huang Hongjun Xiang Key Laboratory of Computational Physical Sciences(Ministry of Education) Institute of Computational Physical SciencesState Key Laboratory of Surface PhysicsDepartment of PhysicsFudan UniversityShanghai 200433China Shanghai Qi Zhi Institute Shanghai 200030China Beijing Computational Science Research Center Beijing 100193China Department of Physics Beijing Normal UniversityBeijing 100193China Collaborative Innovation Center of Advanced Microstructures Nanjing 210093China

Control over magnetic properties by optical stimulation is not only interesting from the physics point of view,but also important for practical applications such as magneto-optical devices.Here,based on a simple tight-binding(TB)model,we propose a general theory of light-induced magnetic phase transition(MPT)in antiferromagnets.Considering the fact that the bandgap of the antiferromagnetic(AFM)phase is usually larger than that of the ferromagnetic(FM)one for a given system,we suggest that light-induced electronic excitation prefers to stabilize the FM state over the AFM one,and will induce an MPT from AFM phase to FM phase once a critical photocarrier concentration(αc)is reached.This theory has been confirmed by performing firstprinciples calculations on a series of 2D van der Waals(vd W)antiferromagnets.Interestingly,a linear relationship betweenαc and the intrinsic material parameters is obtained,in agreement with our TB model analysis.Our general theory paves a new way to manipulate 2D magnetism with high speed and superior resolution.

关键词： first-principles calculation density functional theory two-dimensional materials magnetic phase transition

Clinical practice of emergency department-initiated extracorporeal cardiopulmonary resuscitation for cardiac arrest in adults

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2023年第2期136卷 224-226页

作者： Guowu Xu jinxiang Wang Wenjing Zhou heng jin Yanfen Chai Haojun Fan Shike Hou Ziquan Liu Yanqing Liu Science and Innovation Center Wenzhou Safety(Emergency)InstituteTianjin UniversityWenzhouZhejiang 325000China Department of Emergency Medicine Tianjin Medical University General HospitalTianjin 300052China Department of Pediatric Dentistry Stomatological Hospital of Tianjin Medical UniversityTianjin 300070China Institute of Disaster and Emergency Medicine Tianjin UniversityTianjin 300072China

To the Editor:Cardiac arrest(CA)is one of the leading causes of adult death globally.According to the latest American Heart Association reports,[1]the incidences of Emergency Medical Service-assessed adult out-of-hosp... 详细信息

关键词： cardiac assessed resuscitation

Rehabilitation training improves exercise tolerance after percutaneous coronary intervention

在线全文

学校读者我要写书评

暂无评论

The Journal of Biomedical Research 2012年第4期26卷 248-252页

作者： Fang Cui Yusheng Ren heng jin Bo Cui Department of Rehabilitation Medicine Dongfang HospitalTongji UniversityShanghai 200120China Department of Cardiology Shanghai Changzheng HospitalSecond Military Medical UniversityShanghai 200003China Department of Cardiovascular Medicine the Second Affiliated HospitalNantong UniversityNantongJiangsu 226001China Departments of Surgery and Pathology Duke University Medical CenterDurhamNC27710USA

The aim of this present study was to investigate the effects of training on exercise tolerance of patients with coronary heart disease after percutaneous coronary intervention.Fifty-seven cases of coronary heart disease after percutaneous coronary intervention were divided randomly into the rehabilitation training group（26 cases） and control group（31 cases）.Patients in the rehabilitation training group received rehabilitation training at different stages and exercise intensities 3 d after percutaneous coronary intervention for 3 months.The heart rate,blood pressure,ECG changes in treadmill exercise test,and the frequency of anginal episodes were observed.The results showed that NST and ΣST of ECG and the frequency of anginal episodes were significantly reduced in the rehabilitation training group.In addition,exercise tolerance was improved and the total exercise time was lengthened in these patients.Moreover,ST segment depression time and emergence time of angina with exercise were also lengthened compared with controls（P 〈 0.05,or 0.01）.However,the heart rate and blood pressure before and after exercise of the two groups were similar.The study indicated that rehabilitation training could significantly relieve angina,amend ischemic features of ECG,and improve exercise tolerance of coronary heart disease patients after percutaneous coronary intervention.

关键词： coronary heart disease percutaneous coronary intervention rehabilitation training exercise tolerance treadmill exercise test

休耕对抚仙湖周边农田土壤剖面和浅层地下水中氮累积的影响

在线全文

学校读者我要写书评

暂无评论

环境科学 2024年第6期45卷 3225-3233页

作者：叶远行陈安强李林闵金恒王炽闫辉张丹云南农业大学资源与环境学院昆明650201 云南省农业科学院农业环境资源研究所昆明650201

减少外源氮投入能有效降低农田土壤氮累积和地下水氮污染,休耕是减少外源氮投入的重要措施之一.为探讨农田休耕对土壤剖面和浅层地下水中氮累积的影响,以抚仙湖周边农田土壤剖面和浅层地下水为研究对象,分析了休耕前(2017年12月)和休耕... 详细信息

减少外源氮投入能有效降低农田土壤氮累积和地下水氮污染,休耕是减少外源氮投入的重要措施之一.为探讨农田休耕对土壤剖面和浅层地下水中氮累积的影响,以抚仙湖周边农田土壤剖面和浅层地下水为研究对象,分析了休耕前(2017年12月)和休耕后(2020年8月和2021年4月)农田0~100 cm土壤剖面氮累积和浅层地下水中氮浓度的变化及其两者的关系.结果表明:休耕显著降低了土壤剖面氮含量和储量,休耕后0~30、30~60和60~100 cm土壤剖面TN、ON、DTN、NO_(3)^(-)-N和NH_(4)^(+)-N含量分别降低18.4%~36.5%、16.1%~26.8%、54.0%~130.2%、59.5%~90.8%和60.1%~110.6%.休耕前0~100 cm土壤TN、ON、DTN、NO_(3)^(-)-N和NH_(4)^(+)-N储量分别为(17.20±0.97)t·hm^(-2)、(15.50±1.23)t·hm^(-2)、(0.68±0.06)t·hm^(-2)、(266.8±31.17)kg·hm^(-2)和(18.7±3.04)kg·hm^(-2),休耕后各形态氮储量分别下降了25.5%、23.3%、44.7%、80.1%和59.9%.休耕也改变了浅层地下水中氮浓度和形态构成,休耕后地下水中TN、ON、NO_(3)^(-)-N和NH_(4)^(+)-N浓度分别下降了88.4%、82.7%、92.1%、65.8%,ON/TN和NH_(4)^(+)-N/TN从休耕前的26%和6%升高至休耕后的39%和17%,而NO_(3)^(-)-N/TN从休耕前的61%降至休耕后的41%.地下水氮浓度和形态变化与休耕前后土壤中DTN、NH_(4)^(+)-N、NO_(3)^(-)-N和地下水中p H、ORP、DO等因素密切相关.可见,休耕有效降低了农田土壤剖面氮累积,缓解了浅层地下水氮污染,有利于防止高原湖泊的水质恶化.

关键词：休耕氮储量浅层地下水土壤剖面抚仙湖

龙岩市永定区城乡供水一体化项目管线布置及施工质量控制

在线全文

学校读者我要写书评

暂无评论

山西水利科技 2024年第2期 36-38,44页

作者：江亨锦龙岩市永定区水利水电工程质量技术站福建龙岩364100

多年来,我国多个省市陆续加大投入,开展了城乡供水一体化工作的探索,各地区呈现出不同的模式与做法。如何更好地推进城乡供水一体化建设,做好农村供水,成为需要行业共同思考的话题。通过龙岩市永定区城乡供水一体化项目寨下片区工程实例... 详细信息

多年来,我国多个省市陆续加大投入,开展了城乡供水一体化工作的探索,各地区呈现出不同的模式与做法。如何更好地推进城乡供水一体化建设,做好农村供水,成为需要行业共同思考的话题。通过龙岩市永定区城乡供水一体化项目寨下片区工程实例,论述了管线布置、沟槽开挖、管道铺设、管道回填、压水试验施工技术,供类似工程参考。

关键词：城乡供水一体化供水工程质量控制

An adaptive graph embedding method for feature extraction of hyperspectral images based on approximate NMR model

在线全文

学校读者我要写书评

暂无评论

光电子快报:英文版 2023年第7期19卷 443-448页

作者： QIU Hong WANG Renfang jin heng WANG Feng College of Big Data and Software Engineering Zhejiang Wanli UniversityNingbo 315200China College of Information Shanghai Ocean UniversityShanghai 200120China

This paper introduces an approximate nuclear norm based matrix regression projection(ANMRP) model,an adaptive graph embedding method,for feature extraction of hyperspectral images.The ANMRP utilizes an approximate NMR model to construct an adaptive neighborhood map between samples.The globally optimal weight matrix is obtained by optimizing the approximate NMR model using fast alternating direction method of multipliers(ADMM).The optimal projection matrix is then determined by maximizing the ratio of the local scatter matrix to the total scatter matrix,allowing for the extraction of discriminative features.Experimental results demonstrate the effectiveness of ANMRP compared to related methods.

关键词： approximate embedding matrix

Behavioural analysis and dynamic simulation of the debris flow that occurred in Ganluo County(Sichuan, China) on 30 August 2020

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2022年第6期19卷 1495-1508页

作者： LI Nuo-dong LIU Wei ZHAO jin-heng Chengdu Power Supply Company of State Grid Sichuan Electric Power Company Chengdu 610041China Key Laboratory of Mountain Hazards and Surface Process Institute of Mountain Hazards and EnvironmentChinese Academy of SciencesChengdu 610041China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu 610065China Department of Water Hydropower and Construction Engineering Skill Training Center of State Grid Sichuan Electric Power CompanyChengdu 610000China

On August 30, 2020, a high-intensity storm that dropped 45.4 mm of rain in 5 hours hit the Heixiluo basin and triggered a landslide-generated debris flow event, causing fatalities and damage. The original source of the debris flow was a large slope collapse on a steep hillside. The fallen debris mass was enlarged through sediment entrainment and slope collapse and ultimately buried a bridge at the gully entrance. Approximately 6.9×10;m;of material, including sediments and collapsed slope deposits in the gullies, was entrained, and the maximum erosion depth reached 17 m. A geomorphological analysis was initially performed based on a detailed field investigation to recognize the liquid and solid sources of the debris flow and the areas subjected to deposition and erosion. A map of the erosiondeposition distribution was obtained based on preand post-event DEMs. Using the rainfall estimated by the nearest rain gauge and the solid source estimated by the DEMs, runoff and debris flow propagation was simulated using a liquid-solid two-phase model that considers the effects of runoff and entrainment. The similarity between the estimated and simulated deposition-erosion volumes was satisfactory. The behaviour of debris flows captured in the simulation is broadly in line with the main features of the observed event.

关键词： Debris flow Formation analysis Two-phase model Dynamic simulation

Palladium-catalyzed alkynylative[5+1]carboannulation of 1,3-diarylprop-2-yn-1-yl acetates with terminal alkynes enabled by C-H functionalization

在线全文

学校读者我要写书评

暂无评论

Organic Chemistry Frontiers 2022年第5期9卷 1389-1394页

作者： Jiang-Xi Yu Li-Jun Wu Zhi-Qiang Wang Zhi-Feng Xu jin-heng Li Key Laboratory of Functional Meta-Organic Compounds of Hunan Province Key Laboratory of Functional Organometallic Materials(University of Hunan Province)Hengyang Normal UniversityHengyang 421008China College of Sciences Central South University of Forestry and TechnologyChangsha410004China Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHenan 475004China

A new method for the synthesis of 3-ethynyl-1-methylene-1,2-dihydronaphthalenes via copper-pro-moted palladium-catalyzed intermolecular alkynylative[5+1]carboannulation of 1-arylphenyl-prop-2-yn-1-yl acetates involving C–H functionalization is described.Two terminal alkyne molecules serve as an alkynylation reagent and a one-carbon unit to enable alkynylative[5+1]carboannulation with excellent selectivity control,broad substrate scope and good tolerance of functional groups.

关键词： catalyzed Palladium palladium

Copper-catalyzed oxidative phosphonoheteroarylation of alkenes with phosphonates and N-heteroarenes via P-H/C-H functionalization

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Organic Chemistry Frontiers 2022年第2期9卷 476-480页

作者： Chong-Hui Xu Zhi-Qiang Xiong Yang Li Yan-Ping Zhu jin-heng Li Key Laboratory of Jiangxi Province for Persistent Pollutants Control and Resources Recycle Nanchang Hangkong UniversityNanchang 330063China School of Pharmacy Key Laboratory of Molecular Pharmacology and Drug EvaluationMinistry of EducationCollaborative Innovation Center of Advanced Drug Delivery System and Biotech Drugs in Universities of ShandongYantai UniversityYantaiShandong264005China State Key Laboratory of Applied Organic Chemistry Lanzhou UniversityLanzhou 730000China School of Chemistry and Chemical Engineering Henan Normal UniversityXinxiangHenan 475004China

A copper-catalyzed oxidative intermolecular phosphonoheteroarylation of alkenes with phosphonates and nucleophilic N-heteroarenes(such as indoles and pyrroles)involving P-H/C-H functionalization for the synthesis of highly valuable β-(N-heteroaryl)-alkylphosphonates is disclosed.This method allows the incorporation of two functional groups,a phosphonate and a N-heteroarene,into the alkene in a single reaction step through oxidative formation of the P-centered radicals,addition across the CvC bond,single electron oxidation and C-H functionalization cascades.

关键词： oxidative phosphonate catalyzed