检索结果-南通市图书馆

ON SELF-ABSORPTION CORRECTION IN EXCIMER FLUORESCENCE MEASUREMENTS OF POLYMER SOLUTIONS

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 2000年第5期18卷 465-468页

作者： Xi-gao Jin Zhong Jiang Ming Ni Feng-lian Bai ren-yuan qian institute of chemistry, chinese academy of sciences, beijing 100080, china institute of chemistry Chinese Academy of Sciences Beijing 100080 China

The effect of self absorption on the ratio of excimer to monochromophore emission intensities, I-e/I-m, has been explored by experimentally changing the solution layer thickness of the emission light path traversed in the solution in the right-angle geometry. The result shows that data obtained by front-face geometry are better than those obtained by right-angle geometry even after correction to zero solution thickness. The correction formula based on geometric optics given by Tsai and Torkelson is not adequate.

关键词： excimer fluorescence self absorption polystyrene solution

VISCOELASTIC BEHAVIOR OF THE NON-HOOKE DEFORMATION BEFORE YIELDING IN UNIAXIAL DRAWING OF AMORPHOUS POLY(ETHYLENE TEREPHTHALATE)

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 2001年第4期19卷 399-405页

作者： Zhen-hua yuan De-yan Shen ren-yuan qian Polymer Physics Laboratory Center for Molecular Science, institute of chemistry chinese academy of sciences, beijing 100080 china 中科院化学所高分子物理及化学国家重点实验室北京

Viscoelastic behavior of the non-Hooke deformation of amorphous PET film before yield was investigated in the temperature region 74-80.5 degreesC around the glass transition temperature. The film specimen was drawn to yield point followed by unloading to zero stress, then the residual deformation was held constant; while the subsequent evolution of the stress was recorded. An induction period was found in the course of stress evolution followed by a stress step-increase. The induction period decreases with increasing drawing temperature with an activation energy of 1.10 MJ/mol.K, which is attributed to the time needed for the relaxation of rubbery deformation through cooperative internal rotations. At temperatures lower than 74 degreesC, there is no stress increase or the induction period becomes too long to be observed. Thus the nature of anelasticity in the non-Hooke region before yielding is attributed to stress induced rubbery deformation. The experimental results are interpreted in terms of Perez' theological model of a series connected Hooks spring and a Voigt element consisting of a parallel connected elastic spring and a dashpot.

关键词： pre-yield deformation PET uniaxial drawing non-Hooke deformation viscoelasticity stress induced rubbery deformation

Conceptual design and control method for a noncontact annular electromagnetic stabilized satellite platform

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Aeronautics 2024年第1期37卷 256-270页

作者： He LIAO Daixin WANG yuan ren Weijie WANG institute of Astronautics Nanjing University of Aeronautics and AstronauticsNanjing 211106China Department of Basic Course Space Engineering UniversityHuairou DistrictBeijing 101416China

Disturbance-Free Payload(DFP)spacecraft can meet the requirements of ultra-high attitude pointing accuracy and stability for future space ***,as the main control actuators of DFP spacecraft,Linear Non-Contact Lorentz Actuators(LNCLAs)have control output problems with six-degree-of-freedom coupling and nonlinear effects,which will affect the attitude control performance of DFP *** solve this problem,a novel concept for Non-Contact Annular Electromagnetic Stabilized Satellite Platform(NCAESSP)is proposed in this *** concept is centered on replacing the LNCLAs with a non-contact annular electromagnetic actuator to solve the two problems mentioned ***,for the different control requirements of the payload module and the support module of the NCAESSP,a high-precision attitude controller based on the robust model matching method and a dual quaternion-based adaptive sliding mode controller are ***,the simulation results verify the feasibility and effectiveness of the proposed approach.

关键词： Disturbance-free payload Robust model matching Dual quaternion Sliding mode control Collision avoidance

Light-Activated Virtual Sensor Array with Machine Learning for Non-Invasive Diagnosis of Coronary Heart Disease

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2024年第12期16卷 427-448页

作者： Jiawang Hu Hao qian Sanyang Han Ping Zhang yuan Lu Department of Chemical Engineering Tsinghua UniversityBeijing 100084People’s Republic of China Key Laboratory of Industrial Biocatalysis Ministry of EducationTsinghua UniversityBeijing 100084People’s Republic of China Department of Cardiology Xuanwu HospitalCapital Medical UniversityBeijing 100053People’s Republic of China Department of Cardiology Beijing Tsinghua Changgung HospitalSchool of Clinical MedicineTsinghua UniversityBeijing 102218People’s Republic of China institute of Biopharmaceutical and Health Engineering Shenzhen International Graduate SchoolTsinghua UniversityShenzhen 518055People’s Republic of China

Early non-invasive diagnosis of coronary heart disease(CHD)is ***,it is challenging to achieve accurate CHD diagnosis via detecting *** this work,heterostructured complexes of black phosphorus(BP)and two-dimensional carbide and nitride(MXene)with high gas sensitivity and photo responsiveness were formulated using a self-assembly strategy.A light-activated virtual sensor array(LAVSA)based on BP/Ti_(3)C_(2)Tx was prepared under photomodulation and further assembled into an instant gas sensing platform(IGSP).In addition,a machine learning(ML)algorithm was introduced to help the IGSP detect and recognize the signals of breath samples to diagnose *** to the synergistic effect of BP and Ti_(3)C_(2)Tx as well as photo excitation,the synthesized heterostructured complexes exhibited higher performance than pristine Ti_(3)C_(2)Tx,with a response value 26%higher than that of pristine Ti_(3)C_(2)*** addition,with the help of a pattern recognition algorithm,LAVSA successfully detected and identified 15 odor molecules affiliated with alcohols,ketones,aldehydes,esters,and ***,with the assistance of ML,the IGSP achieved 69.2%accuracy in detecting the breath odor of 45 volunteers from healthy people and CHD *** conclusion,an immediate,low-cost,and accurate prototype was designed and fabricated for the noninvasive diagnosis of CHD,which provided a generalized solution for diagnosing other diseases and other more complex application scenarios.

关键词： Black phosphorus/MXene heterostructures Light-activated virtual sensor array Diagnosis of coronary heart disease Machine learning

Time-synchronous-averaging-spectrum based on super-resolution analysis and application in bearing fault signal identification

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第7期25卷 573-585页

作者： Zengle ren yuan WANG Huiyue TANG Xin'an CHEN Wei FENG Guangdong Provincial Key Laboratory of Construction Robotics and Intelligent Construction Shenzhen Institute of Advanced TechnologyChinese Academy of SciencesShenzhen518055China Shenzhen EBORAIL Technology Co. Ltd.Shenzhen518038China National Supercomputing Center in Shenzhen Shenzhen518055China State Key Lab of Rail Traffic Control and Safety Beijing Jiaotong UniversityBeijing100044China University of chinese academy of sciences Beijing100190China Shenzhen University of Advanced Technology Shenzhen518107China

Time-synchronous-averaging(TSA)is based on the idea of denoising by averaging,and it extracts the periodic components of a quasiperiodic signal and keeps the extracted waveform *** paper studies the mathematical properties of TSA,where three propositions are given to reveal the nature of *** paper also proposes a TSA-spectrum based on super-resolution analysis and it decomposes a signal without using any base *** contrast to discrete Fourier transform spectrum(DFT-spectrum),which is a spectrum in frequency domain,TSA-spectrum is a period-based spectrum,which can present more details of the cross effects between different periodic components of a quasiperiodic ***,a case study is carried out using bearing fault analysis to illustrate the performance of TSA-spectrum,where the rotation speed fluctuation of the shaft is estimated,which is about 0.12 ms *** extracted fault signals are presented and some insights are *** believe that this paper can provide new motivation for TSA-spectrum to be widely used in applications involving quasiperiodic signal processing(QSP).

关键词： Time-synchronous-averaging(TSA) Spectrum Quasiperiodic signal processing(QSP) Super-resolution analysis Bearingfaultdetection

Predicting the Risk of Arterial Stiffness in Coal Miners Based on Different Machine Learning Models

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

Biomedical and Environmental sciences 2024年第1期37卷 108-111页

作者： CHEN qian Wei HUANG Xue Zan DING Yu ZHU Feng ren WANG Jia ZOU yuan Jie DU yuan Zhen ZHANG Ya Jun HUI Zi Wen ZHU Feng Lin MU Min The Project was supported by Open Research Grant of Joint National-Local Engineering Research Centre for Safe and Precise Coal Mining Anhui University of Science and TechnologyHefei 232001AnhuiChina School of Public Health Anhui University of Science and TechnologyHefei 232001AnhuiChina Key Laboratory of Industrial Dust Prevention and Control Occupational Safety and HealthMinistry of EducationAnhui University of Science and TechnologyHefei 232001AnhuiChina Anhui institute of Occupational Safety and Health Anhui University of Science and TechnologyHefei 232001AnhuiChina Joint Research Center of Occupational Medicine and Health Institute of Grand HealthHefei Comprehensive National Science CenterAnhui University of Science and TechnologyHefei 232001AnhuiChina Department of Occupational&Environmental Health School of Public HealthTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030HubeiChina Key Laboratory of Environment and Health Ministry of Education&Ministry of Environmental Protectionand State Key Laboratory of Environmental Health(Incubating)School of Public HealthTongji Medical CollegeHuazhong University of Science and TechnologyWuhan 430030HubeiChina

Coal is one of the world’s main energy resources,accounting for approximately 68%of china’s current total power ***,several studies have demonstrated that dust,exhaust fumes,and other harmful factors in coal mines increase the risk of cardiovascular disease(CVD)among miners^([1]).Arterial stiffness(AS)is an independent risk factor of CVD,and epidemiological studies have shown that AS plays a vital role in assessing the risk of CVD^([2]).

关键词： Arterial cardiovascular assessing

SMALL ANGLE LIGHT SCATTERING MEASUREMENT OF THE ISOTROPIC TO NEMATIC TRANSITION OF A SIDE CHAIN NEMATIC POLYMETHACRYLATE

在线全文

学校读者我要写书评

暂无评论

chinese Journal of Polymer Science 2002年第5期20卷 431-437页

作者： Zhong-ming Hu ren-yuan qian Shou-xi Chen Xiao-fang Chen Qi-feng Zhou Centre for Molecular Science, institute of chemistry chinese academy of sciences, beijing 100080, china Department of Polymer Science & Engineering College of chemistry & Molecular Engineering Peking University beijing 100871, china Centre for Molecular Science Institute of Chemistry Chinese Academy of Sciences 北京 100080 Department of Polymer Science & Engineering College of Chemistry & Molecular Engineering Peking University 北京 100871

The kinetics of I-->N transition of a side chain nematic polymethacrylate has been studied by small angle depolarized light scattering intensity measurements using a charge coupled device linear image sensor. The polymer shows the transition temperatures K52N79I in degreesC, The H-v scattering intensity T(q,t) during the transition I (at 80.2degreesC)-->N (at 75.8degreesC) shows that T(q) is independent of q for all t, and during the initial stage (in 6 s) T(t) increases exponentially with t. In the later stage of the transition T(t) approaches a saturation value in 2 min. This experimental result indicates that the I-->N transition of a liquid crystalline polymer is a spinodal type of phase transition mediated by orientation fluctuation.

关键词： side chain nematic polymer isotropic-nematic transition small angle depolarized light scattering

Patent-based technological developments and surfactants application of lithium-ion batteries fire-extinguishing agent

在线全文

学校读者我要写书评

暂无评论

Journal of Energy chemistry 2024年第1期88卷 39-63,I0002页

作者： Jianqi Zhang Tao Fan Shuai yuan Chongye Chang Kuo Wang Ziwei Song Xinming qian State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100084China Industrial Safety Research institute China Academy of Safety Science and TechnologyBeijing 100012China Fire Engineering Department China People’s Police UniversityLangfang 065000HebeiChina

While newer,more efficient Lithium-ion batteries(LIBs)and extinguishing agents have been developed to reduce the occurrence of thermal runaway accidents,there is still a scarcity of research focused on the application of surfactants in different LIBs extinguishing agents,particularly in terms of patented *** aim of this review paper is to provide an overview of the technological progress of LIBs and LIBs extinguishing agents in terms of patents in Korea,Japan,Europe,the United States,china,*** initial part of this review paper is sort out LIBs technology development in different *** addition,to compare LIBs extinguishing agent progress and challenges of liquid,solid,combination of multiple,and *** subsequent section of this review focuses on an in-depth analysis dedicated to the efficiency and challenges faced by the surfactants corresponding design principles of LIBs extinguishing agents,such as nonionic and anionic surfactants.A total of 451,760 LIBs-related patent and 20 LIBs-fire-extinguishing agent-related patent were included in the *** extinguishing effect,cooling performance,and anti-recombustion on different agents have been *** a comprehensive comparison of these agents,this review suggests that temperature-sensitive hydrogel extinguishing agent is ideal for the effective control of LIBs *** progress and challenges of surfactants have been extensively examined,focusing on key factors such as surface activity,thermal stability,foaming properties,environmental friendliness,and electrical ***,it is crucial to emphasize that the selection of a suitable surfactant must align with the extinguishing strategy of the extinguishing agent for optimal firefighting effectiveness.

关键词： LIBs Fire-extinguishing agent Surfactants Patent

Grow rice under sunshine of Xizang/Tibet:promise and challenges

在线全文

学校读者我要写书评

暂无评论

Journal of Genetics and Genomics 2024年第3期51卷 265-267页

作者： Chunkun Fan Xiaoming Zheng Qingbo yuan Tao Wang qian qian Qingyun Bu Fan Chen Agricultural institute Xizang Academy of Agricultural and Animal Husbandry ScienceLasaXizang 850032China National Key Facility for Crop Gene Resources and Genetic Improvement Institute of Crop SciencesChinese Academy of AgriculturalSciencesBeijing 100081China Sanya National Research institute of Breeding in Hainan Chinese Academy of Agricultural SciencesBeijing 572000China Yazhouwan National Laboratory SanyaHainan 572704China Chengdu institute of Biology Chinese Academy of SciencesChengduSichuan 610041China Northeast institute of Geography and Agroecology Chinese Academy of SciencesHarbinHeilongjiang 150081China

Xizang,previously known as Tibet,is located in the southwest region of china and is the highest region of the Qinghai-Tibet Plateau(QzP),with an average altitude of over 4000 *** the development of modern agriculture,the grain productivity in Xizang has been effectively *** total annual grain production has increased from 558,700 tons in 1988 to 1044,000 tons in 2018(Xizang Statistical Year Book).

关键词： sunshine Tibet southwest