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刮板输送机负载预测方法的研究 预览
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作者 王杰 《煤炭科技》 2020年第1期32-35,共4页
刮板输送机电动机电流的波动反映了负载的变化,为研究刮板输送机负载与电流关系,准确预测刮板输送机负载,建立了小波神经网络模型进行分析,并通过工程试验验证,刮板输送机机尾和机头电流预测的平均误差均小于5%;样本测试时间在0. 1 s左... 刮板输送机电动机电流的波动反映了负载的变化,为研究刮板输送机负载与电流关系,准确预测刮板输送机负载,建立了小波神经网络模型进行分析,并通过工程试验验证,刮板输送机机尾和机头电流预测的平均误差均小于5%;样本测试时间在0. 1 s左右,可以满足刮板输送机的实时性和精度要求。 展开更多
关键词 小波神经网络法 刮板输送机 负载预测 电流 电流预测的平均误差
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High rate and cycling stable Li metal anodes enabled with aluminum-zinc oxides modified copper foam 预览
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作者 Songtao Lu Zhida Wang +5 位作者 He Yan Rui Wang Ke Lu Yingwen Cheng Wei Qin Xiaohong Wu 《能源化学:英文版》 SCIE EI CAS CSCD 2020年第2期87-92,共6页
Metallic Li is a promising anode material for high energy density batteries but it suffers from poor stability and formation of unsafe dendrites. Previous studies demonstrated that 3 D metal foams are able to improve ... Metallic Li is a promising anode material for high energy density batteries but it suffers from poor stability and formation of unsafe dendrites. Previous studies demonstrated that 3 D metal foams are able to improve the stability of Li metal but the properties of these foams are inherently limited. Here we report a facile surface modification approach via magnetron sputtering of mixed oxides that effectively modulate the properties of Cu foams for supporting Li metal with remarkable stability. We discovered that hybrid Li anodes with Li metal thermally infused to aluminum-zinc oxides(AZO) coated Cu foams have significantly improved stability and reactivity compared with pristine Li foils and Li infused to unmodified Cu foams. Full cells assembled with a Li Fe PO4 cathode and a hybrid anode maintained low and stable charge-transfer resistance(<50) during 500 cycles in carbonate electrolytes, and exhibited superior rate capability(~100 m Ah g-1 at 20 C) along with better electrochemical reversibility and surface stability. The AZO modified Cu foams had superior mechanical strength and afforded the hybrid anodes with minimized volume change without the formation of dendrites during battery cycling. The rational construction of surface architecture to precisely control Li plating and stripping may have great implications for the practical applications of Li metal batteries. 展开更多
关键词 Composite Lianode Metal foams Surface modification Limetal batteries 3D current collector
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Lack of proper reimbursement is hampering adoption of minimally invasive gastrointestinal endoscopy in North America 预览
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作者 Shahzad Iqbal Aman Ali +1 位作者 Arham Razzaq Eman Shahzad 《世界胃肠内镜杂志:英文版(电子版)》 2020年第1期49-52,共4页
Endoscopic submucosal dissection(ESD)and related procedures are minimally invasive and cost-effective alternates to surgery.However,there is no approved or listed current procedural terminology(CPT)for ESD.We aimed to... Endoscopic submucosal dissection(ESD)and related procedures are minimally invasive and cost-effective alternates to surgery.However,there is no approved or listed current procedural terminology(CPT)for ESD.We aimed to review the current reimbursement process hurdles for ESD procedures in private practice model in United States.We reviewed the data of two advanced endoscopists(one in New York and other in Pennsylvania State)performing ESD in their private practice set-ups.We found the reimbursement process was complex,with number of refusals varied from 0-9 for ESD procedures.It was not paid at all in 8.3%of cases by the medical insurance.Endoscopic mucosal resection,which is considered inferior as compared to ESD,but has a listed CPT,was denied in only 0.83%cases.Our data highlights the billing hurdles by the endoscopists to adopt ESD-related procedures in private practice model. 展开更多
关键词 Endoscopic SUBMUCOSAL dissection Lack of REIMBURSEMENT Current PROCEDURAL terminology MINIMALLY invasive gastrointestinal endoscopy North America
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Dynamical Control of Asymmetrically Oblique Tidal Currents to the Sedimentary Characteristics and Development of Linear Sand Ridges in the Liaodong Shoal, East Bohai Sea 预览
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作者 ZHANG Lianjie ZHU Longhai +3 位作者 WU Jianzheng HU Rijun WANG Peng ZHANG Pan 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2020年第1期101-112,共12页
The Liaodong Shoal is a group of linear sand ridges located in the east Bohai Sea of China.In this study,54 surface sediment samples have been collected,current measurements at 4 stations have been carried out and bat... The Liaodong Shoal is a group of linear sand ridges located in the east Bohai Sea of China.In this study,54 surface sediment samples have been collected,current measurements at 4 stations have been carried out and bathymetric data were obtained.The current directions are rightward deflected relative to the strikes of the sand ridges.Affected by the narrowing effect of the ridge,the current velocities exhibited an anti-‘C’type vertical profile.The velocities of the lower currents linearly correlate with the water depths.The near-bed current velocities over the troughs are estimated to be higher than those over the ridges,and this feature could be explained by the loss of kinetic energy together with the conversion between kinetic energy and gravitational potential energy.The sedimentary characteristics that are compatible with the tidal dynamics are developed across the ridges and troughs,including grain size compositions,grain size parameters,mineral compositions and Dhm indexes.The existence of the angles between the current directions and the strikes of the sand ridges is the key factor for the growth of the sand ridges.The asymmetric hydrodynamic features between the flood and ebb currents lead to the differences in the topographical and sedimentary characteristics on both sides of a sand ridge.Insufficient material supply led to the degradation of the sand ridges,and the reduction of the tidal current intensity has led to the development of the subordinate sand ridges in the troughs.Sand ridges are migrating. 展开更多
关键词 Liaodong Shoal tidal current ridge heavy minerals sedimentary characteristic development and evolution
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Salt/current-triggered stabilization of β-cyclodextrins encapsulated host-guest low-molecular-weight gels
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作者 Huan Xu Chaoyu Zhou +5 位作者 Chuanjiang Jian Sunhai Yang Miaochang Liu Xiaobo Huang Wenxia Gao Huayue Wu 《中国化学快报:英文版》 SCIE CAS CSCD 2020年第2期369-372,共4页
Host-guest supramolecular gels were developed via the self-assembly of inclusion complexes(ICs) ofβ-cyclodextrins/phenylboronic acid gelator(PBA).Salts and current were involved in the self-assembly to stabilize the ... Host-guest supramolecular gels were developed via the self-assembly of inclusion complexes(ICs) ofβ-cyclodextrins/phenylboronic acid gelator(PBA).Salts and current were involved in the self-assembly to stabilize the host-guest gels.The stability of the gels was greatly improved after salts were added.The stable time of gels was extended from 2.5 h to 120 h with the addition of NH_4 NO_3 at the concentration of 2.5×10^(-2) g/mL.The morphology of the gel was affected by the concentrations of NH_4NO_3.SEM images revealed that the gels were three-dimensional nanofibrous networks,the sizes of fibers decreased with decreasing NH_4NO_3 concentrations,which affected the stability of gels,further proved by the rheological properties of gels.More stable gels were obtained with current stimulation,the stable time of the gel was increased from 2.5 h to 55 h with current by adding NaBF_4.The current also exhibited significant influence on the aggregation as the voltage varied(0-500 mV) with a constant concentration of salts.The result showed the self-assembly process of host-guest gel could be well controlled via the addition of salts and current to desired morphology and stability. 展开更多
关键词 Supramolecular gel Inclusion complex Host-guest interaction Salt Current Stability
单相高温超导电缆屏蔽层电流仿真及实验研究 预览
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作者 张会明 丘明 +3 位作者 杜怡君 徐维彬 韩云武 邓祥力 《电线电缆》 2020年第1期14-18,共5页
高温超导电缆的屏蔽层在非对称故障情况下会在变电站间产生入地电流,影响系统的零序阻抗。采用数值模拟与实验相结合的方法,研究单相高温超导电缆的屏蔽层电流的影响因素。首先建立了超导电缆的电磁数值仿真模型,通过解析公式对模型进... 高温超导电缆的屏蔽层在非对称故障情况下会在变电站间产生入地电流,影响系统的零序阻抗。采用数值模拟与实验相结合的方法,研究单相高温超导电缆的屏蔽层电流的影响因素。首先建立了超导电缆的电磁数值仿真模型,通过解析公式对模型进行验证,然后仿真计算不同屏蔽层等效电阻下,屏蔽层感应电流和感应电压大小。结果表明,感应电流和感应电压的主要影响因素是屏蔽层电阻的大小,且屏蔽层与导电层间的电磁关系可以采用变压器模型进行定性分析。同时,搭建了超导电缆屏蔽层电流的测试实验平台,初步验证了屏蔽层阻抗对屏蔽层电流的影响规律。 展开更多
关键词 超导电缆 屏蔽层 感应电流 电阻 数值仿真
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A systematical study of the chiral magnetic effects at the RHIC and LHC energies
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作者 陈帮祥 冯笙琴 《中国物理C:英文版》 SCIE CAS CSCD 2020年第2期107-114,共8页
Considering the magnetic field response of the QGP medium,we perform a systematical study of the chiral magnetic effect(CME),and make a comparison with the experimental results for the background-subtracted correlator... Considering the magnetic field response of the QGP medium,we perform a systematical study of the chiral magnetic effect(CME),and make a comparison with the experimental results for the background-subtracted correlator H at the energies of the RHIC Beam Energy Scan(BES)and the LHC energy.The CME signals from our computations show a centrality trend and beam energy dependence that are qualitatively consistent with the experimental measurements of the charge dependent correlations.The time evolution of the chiral electromagnetic current at the RHIC and LHC energies is systematically studied.The dependence of the time-integrated current signal on the beam energy√s with different centralities is investigated.Our phenomenological analysis shows that the time-integrated electromagnetic current is maximal near the collision energy√s≈39 GeV.The qualitative trend of the induced electromagnetic current is in agreement with the CME experimental results at the RHIC and LHC energies. 展开更多
关键词 chiral magnetic effect chiral electromagnetic current charge separations
Reversibility of visual field defects through induction of brain plasticity:vision restoration,recovery and rehabilitation using alternating current stimulation 预览
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作者 Bernhard A.Sabel Ying Gao Andrea Antal 《中国神经再生研究:英文版》 SCIE CAS CSCD 2020年第10期1799-1806,共8页
For decades visual field defects were considered irreversible because it was thought that in the visual system the regeneration potential of the neuronal tissues is low.Nevertheless,there is always some potential for ... For decades visual field defects were considered irreversible because it was thought that in the visual system the regeneration potential of the neuronal tissues is low.Nevertheless,there is always some potential for partial recovery of the visual field defect that can be achieved through induction of neuroplasticity.Neuroplasticity refers to the ability of the brain to change its own functional architecture by modulating synaptic efficacy.It is maintained throughout life and just as neurological rehabilitation can improve motor coordination,visual field defects in glaucoma,diabetic retinopathy or optic neuropathy can be improved by inducing neuroplasticity.In ophthalmology many new treatment paradigms have been tested that can induce neuroplastic changes,including non-invasive alternating current stimulation.Treatment with alternating current stimulation(e.g.,30 minutes,daily for 10 days using transorbital electrodes and~10 Hz)activates the entire retina and parts of the brain.Electroencephalography and functional magnetic resonance imaging studies revealed local activation of the visual cortex,global reorganization of functional brain networks,and enhanced blood flow,which together activate neurons and their networks.The future of low vision is optimistic because vision loss is indeed,partially reversible. 展开更多
关键词 alternating current stimulation glaucoma low vision optic nerve REHABILITATION RECOVERY stress VISION vision restoration therapy visual field
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Protocol on transcranial alternating current stimulation for the treatment of major depressive disorder:a randomized controlled trial
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作者 Hong-Xing Wang Kun Wang +24 位作者 Wen-Rui Zhang Wen-Feng Zhao Xiao-Tong Yang Li Wang Mao Peng Zhi-Chao Sun Qing Xue Yu Jia Ning Li Kai Dong Qian Zhang Shu-Qin Zhan Bao-Quan Min Chun-Qiu Fan Ai-Hong Zhou Hai-Qing Song Lu Yin Tian-Mei Si Jing Huang Jie Lu Hai-Xia Leng Wei-Jun Ding Yuan Liu Tian-Yi Yan Yu-Ping Wang 《中华医学杂志:英文版》 SCIE CAS CSCD 2020年第1期61-67,共7页
Background:Transcranial alternating current stimulation(tACS)offers a new approach for adult patients with major depressive disorder(MDD).The study is to evaluate the efficacy and safety of tACS treating MDD.Methods:T... Background:Transcranial alternating current stimulation(tACS)offers a new approach for adult patients with major depressive disorder(MDD).The study is to evaluate the efficacy and safety of tACS treating MDD.Methods:This is an 8-week,double-blind,randomized,placebo-controlled study.Ninety-two drug-naive patients with MDD aged 18 to 65 years will receive 20 daily 40-min,77.5-Hz,15-mA sessions of active or sham tACS targeting the forehead and both mastoid areas on weekdays for 4 consecutive weeks(week 4),following a 4-week observation period(week 8).The primary outcome is the remission rate defined as the 17-item Hamilton depression rating scale(HDRS-17)score≤7 at week 8.Secondary outcomes are the rates of response at weeks 4 and 8 and rate of remission at week 4 based on HDRS-17,the proportion of participants having improvement in the clinical global impression-improvement,the change in HDRS-17 score(range,0-52,with higher scores indicating more depression)over the study,and variations of brain imaging and neurocognition from baseline to week 4.Safety will be assessed by vital signs at weeks 4 and 8,and adverse events will be collected during the entire study.Discussion:The tACS applied in this trial may have treatment effects on MDD with minimal side effects.Trial registration:Chinese Clinical Trial Registry,ChiCTR1800016479;http://www.chictr.org.cn/showproj.aspx?proj=22048. 展开更多
关键词 Major depressive disorder Transcranial alternating current stimulation TREATMENT TRIAL
Review on Tidal Energy Technologies and Research Subjects 预览
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作者 Chul Hee JO Su Jin HWANG 《中国海洋工程:英文版》 SCIE EI CSCD 2020年第1期137-150,共14页
Tidal current power is one of the promising and reliable renewable energies with the advantage of continuous and predictable resource. It can make stable electricity regardless of weather conditions or seasons all yea... Tidal current power is one of the promising and reliable renewable energies with the advantage of continuous and predictable resource. It can make stable electricity regardless of weather conditions or seasons all year around. The required technologies for tidal current power in the ocean have been developed for years and now recognized that it could be commercialized after intensive field tests and successful demonstrations. There are several tidal farm development projects in the world, such as the MeyGen project in UK with its commercialization at hand. However, various research subjects in the tidal current energy field are seeking improvements and industrialization of tidal current power in terms of economy and technical reliability. This paper introduces the resource assessment procedure of tidal energy that has been applied in Korea coastal regions. The key research subjects for tidal current power together with the interaction effect of multi-arrangement is described. Also, this paper is to introduce the research output of each subject such as turbine design, experimental validation, turbine interaction and wake, multi-array module, FSI (fluid-structure interaction), and duct application. 展开更多
关键词 TIDAL current power RESOURCE assessment TURBINE design experimental VALIDATION TURBINE INTERACTION multi arrangement FSI(fluid-structure interaction)
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Discharge simulation and volt-second consumption analysis during ramp-up on the CFETR tokamak
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作者 刘成岳 吴斌 +6 位作者 钱金平 李国强 侯雅巍 韦维 陈美霞 雷明准 郭勇 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第2期356-361,共6页
The plasma current ramp-up is an important process for tokamak discharge,which directly affects the quality of the plasma and the system resources such as volt-second consumption and plasma current profile.The China F... The plasma current ramp-up is an important process for tokamak discharge,which directly affects the quality of the plasma and the system resources such as volt-second consumption and plasma current profile.The China Fusion Engineering Test Reactor(CFETR)ramp-up discharge is predicted with the tokamak simulation code(TSC).The main plasma parameters,the plasma configuration evolution and coil current evolution are given out.At the same time,the volt-second consumption during CFETR ramp-up is analyzed for different plasma shaping times and different plasma current ramp rates dIP/dt with/without assisted heating.The results show that the earlier shaping time and the faster plasma current ramp rate with auxiliary heating will enable the volt-second to save 5%-10%.At the same time,the system ability to provide the volt-second is probably 470 V·s.These simulations will give some reference to engineering design for CFETR to some degree. 展开更多
关键词 plasma current ramp-up China Fusion Engineering Test Reactor tokamak simulation code volt-second consumption
Scalable fabrication of printed Zn//MnO2 planar micro-batteries with high volumetric energy density and exceptional safety
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作者 Xiao Wang Shuanghao Zheng +6 位作者 Feng Zhou Jieqiong Qin Xiaoyu Shi Sen Wang Chenglin Sun Xinhe Bao Zhong-Shuai Wu 《国家科学评论:英文版》 CSCD 2020年第1期64-72,共9页
The rapid development of printed and microscale electronics imminently requires compatible micro-batteries(MBs)with high performance,applicable scalability,and exceptional safety,but faces great challenges from the ev... The rapid development of printed and microscale electronics imminently requires compatible micro-batteries(MBs)with high performance,applicable scalability,and exceptional safety,but faces great challenges from the ever-reported stacked geometry.Herein the first printed planar prototype of aqueous-based,high-safety Zn//MnO2 MBs,with outstanding performance,aesthetic diversity,flexibility and modularization,is demonstrated,based on interdigital patterns of Zn ink as anode and MnO2 ink as cathode,with high-conducting graphene ink as a metal-free current collector,fabricated by an industrially scalable screen-printing technique.The planar separator-free Zn//MnO2 MBs,tested in neutral aqueous electrolyte,deliver a high volumetric capacity of 19.3 mAh/cm^3(corresponding to 393 mAh/g)at 7.5 mA/cm^3,and notable volumetric energy density of 17.3 mWh/cm^3,outperforming lithium thin-film batteries(≤10 mWh/cm^3).Furthermore,our Zn//MnO2 MBs present long-term cyclability having a high capacity retention of 83.9%after 1300 cycles at 5 C,which is superior to stacked Zn//MnO2 batteries previously reported.Also,Zn//MnO2 planar MBs exhibit exceptional flexibility without observable capacity decay under serious deformation,and remarkably serial and parallel integration of constructing bipolar cells with high voltage and capacity output.Therefore,low-cost,environmentally benign Zn//MnO2 MBs with in-plane geometry possess huge potential as high-energy,safe,scalable and flexible microscale power sources for direction integration with printed electronics. 展开更多
关键词 low cost PRINTED PLANAR Zn//MnO2 micro-batteries METAL-FREE current collectors
Discussion on the Countermeasures of Rocky Desertification Control in Western China: Based on Current Situation of Rocky Desertification Control in Guangxi 预览
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作者 Haiyan GAN 《气象与环境研究:英文版》 CAS 2020年第2期68-72,75,共6页
First,current situation of rocky desertification control in Guangxi was surveyed via the methods of literature review,field investigation and informal discussion. The results displayed that new progress has been made ... First,current situation of rocky desertification control in Guangxi was surveyed via the methods of literature review,field investigation and informal discussion. The results displayed that new progress has been made in the study of control techniques and models for rocky desertification in Guangxi,and typical control models of " mountain-water-field-forest-road comprehensive control", " ecological agriculture planting-agricultural tourism", " three-in-one" appeared. Then,systematic analysis on the situation of rocky desertification control in Guangxi was conducted. Some problems are found: at present,the prevention and control mechanism of rocky desertification in Guangxi is not perfect,and there is no joint force among departments;there is low capital input and single source channel;the contradiction between survival and ecology is prominent,and the enthusiasm of the masses to participate is not high;there is imperfect supporting policy mechanism,and economic development and ecological protection are unbalanced. For these problems,relevant suggestions and safeguard measures are proposed from comprehensive management,governance planning,technical support and policy support. The research aims to provide theoretical foundation and scientific basis for future rocky desertification control in Guangxi. 展开更多
关键词 Rocky desertification CONTROL Current situation COUNTERMEASURES GUANGXI
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电压及电流对等离子喷涂Mo涂层微观组织和性能的影响
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作者 张帆 胡勇 +2 位作者 梁爱民 牛博龙 祖嘉琦 《热加工工艺》 北大核心 2020年第2期84-88,93共6页
采用等离子喷涂技术在45钢表面制备纯Mo涂层,研究了喷涂高电压、低电流参数下涂层表面与截面的微观组织与性能。结果表明:等离子喷涂过程中电压参数变化对该涂层组织和性能的影响较之电流参数变化更为明显;等离子喷涂电压降低同时H2流... 采用等离子喷涂技术在45钢表面制备纯Mo涂层,研究了喷涂高电压、低电流参数下涂层表面与截面的微观组织与性能。结果表明:等离子喷涂过程中电压参数变化对该涂层组织和性能的影响较之电流参数变化更为明显;等离子喷涂电压降低同时H2流量减少,粉末颗粒熔化时间得以延长,但运动速度和动能下降,导致涂层沉积率和孔隙率降低,涂层变薄;喷涂电流降低使粉末熔化质量下降,同时受到未熔粉末反弹因素影响,涂层厚度和沉积率也相应减少;当等离子喷涂电压为165 V、电流为360 A时,制备出的纯Mo涂层沉积率较高且具有较好的组织和综合性能,其中涂层表面硬度为757 HV0.5、粗糙度Ra为2.26μm。 展开更多
关键词 等离子喷涂 Mo涂层 电压 电流
Small interplanetary magnetic flux rope
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作者 FENG HengQiang ZHAO GuoQing WANG JieMin 《中国科学:技术科学英文版》 SCIE EI CAS CSCD 2020年第2期183-194,共12页
Small interplanetary magnetic flux ropes(SIMFRs) are often detected by space satellites in the interplanetary space near 1 AU.These ropes can be fitted by a cylindrically symmetric magnetic model. The durations of SIM... Small interplanetary magnetic flux ropes(SIMFRs) are often detected by space satellites in the interplanetary space near 1 AU.These ropes can be fitted by a cylindrically symmetric magnetic model. The durations of SIMFRs are usually <12 h, and the diameters of SIMFRs are <0.20 AU and show power law distribution. Most SIMFRs are observed in the typically slow solar wind(<500 km/s), and only several events are observed with high speed(>700 km/s). Some SIMFRs demonstrate abnormal heavy ion compositions, such as abnormally high He abundance, abnormally high average iron ionization, and enhanced O7+abundance. These SIMFRs originate from remarkably hot coronal origins. Approximately 74.5% SIMFRs exhibit counterstreaming suprathermal electron signatures. Given their flux rope configuration, SIMFRs are potentially more effective for substorms. SIMFRs and magnetic clouds have many similar observational properties but also show some different observations.These similar properties may indicate that SIMFRs are the interplanetary counterparts of small coronal mass ejections. Some direct bodies of evidence have confirmed that several SIMFRs are interplanetary counterparts of CMEs. However, their different properties may imply that some SIMFRs have interplanetary origins. Therefore, one of the main aims of future research on SIMFRs is to determine whether SIMFRs originate from two different sources, that is, some events are formed in the solar coronal atmosphere, whereas others originate from the interplanetary space. Finally, in this paper, we offer some prospects that should be addressed in the future. 展开更多
关键词 magnetic flux ropes magnetic cloud coronal mass ejection heliospheric current sheet
Evaluation of polarization field in InGaN/GaN multiple quantum well structures by using electroluminescence spectra shift
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作者 陈平 赵德刚 +8 位作者 江德生 杨静 朱建军 刘宗顺 刘炜 梁锋 刘双韬 邢瑶 张立群 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第3期221-224,共4页
In order to investigate the inherent polarization intensity in InGaN/GaN multiple quantum well(MQW) structures,the electroluminescence(EL) spectra of three samples with different GaN barrier thicknesses of 21.3 nm, 11... In order to investigate the inherent polarization intensity in InGaN/GaN multiple quantum well(MQW) structures,the electroluminescence(EL) spectra of three samples with different GaN barrier thicknesses of 21.3 nm, 11.4 nm, and 6.5 nm are experimentally studied. All of the EL spectra present a similar blue-shift under the low-level current injection,and then turns to a red-shift tendency when the current increases to a specific value, which is defined as the turning point.The value of this turning point differs from one another for the three InGaN/GaN MQW samples. Sample A, which has the GaN barrier thickness of 21.3 nm, shows the highest current injection level at the turning point as well as the largest value of blue-shift. It indicates that sample A has the maximum intensity of the polarization field. The red-shift of the EL spectra results from the vertical electron leakage in InGaN/GaN MQWs and the corresponding self-heating effect under the high-level current injection. As a result, it is an effective approach to evaluate the polarization field in the InGaN/GaN MQW structures by using the injection current level at the turning point and the blue-shift of the EL spectra profiles. 展开更多
关键词 InGaN/GaN multiple quantum well(MQW) polarization field electroluminescence spectra shift electron leakage current
Displacement damage in optocouplers induced by high energy neutrons at back-n in China Spallation Neutron Source
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作者 徐瑞 王祖军 +7 位作者 薛院院 宁浩 刘敏波 郭晓强 姚志斌 盛江坤 马武英 董观涛 《中国物理B:英文版》 SCIE EI CAS CSCD 2020年第1期307-310,共4页
Neutron radiation experiments of optocouplers at back-streaming white neutrons(back-n)in China Spallation Neutron Source(CSNS)are presented.The displacement damages induced by neutron radiation are analyzed.The perfor... Neutron radiation experiments of optocouplers at back-streaming white neutrons(back-n)in China Spallation Neutron Source(CSNS)are presented.The displacement damages induced by neutron radiation are analyzed.The performance degradations of two types of optocouplers are compared.The degradations of current transfer ratio(CTR)are analyzed,and the mechanisms induced by radiation are also demonstrated.With the increase of the accumulated fluence,the CTR is degrading linearly with neutron fluence.The radiation hardening of optocouplers can be improved when the forward current is increased.Other parameters related to CTR degradation of optocouplers are also analyzed. 展开更多
关键词 China Spallation Neutron Source OPTOCOUPLER neutron radiation displacement damage current transfer ratio
Research on Time-Domain Transfer Impedance Measurement Technology for High Frequency Current Transformers in Partial Discharge Det ection of Cables
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作者 宋思蒙 陈孝信 +4 位作者 钱勇 王辉 张悦 盛戈皞 江秀臣 《上海交通大学学报:英文版》 EI 2020年第1期10-17,共8页
We focus on the high frequency current method which is widely applied in the partial discharge(PD)detection of cables.Aiming at guaranteeing the accuracy of this method,we study an innovative time-domain technology fo... We focus on the high frequency current method which is widely applied in the partial discharge(PD)detection of cables.Aiming at guaranteeing the accuracy of this method,we study an innovative time-domain technology for effectively measuring the transfer impedance of the high frequency current transformers(HFCTs).The proposed technology called pulse injection method obtains the system response under the excitation of the wide-band instantaneous pulse signal.Firstly,by studying the working principle of HFCTs,we summarize that the bandwidth of the selected signal acquisition device should be at least 100 MHz to ensure measurement accuracy.Secondly,Gauss pulse and square wave pulse are generated to determine the effects of different sources.The measurement results indicate that Gauss pulse is more suitable for pulse injection method,and the rise time should be under 10 ns to improve the starting frequency of oscillation distortion.Finally,the transfer impedance curves of five types of HFCTs are acquired by both pulse injection and traditional point-frequency methods.The measurement results show a remarkable consistency between two methods.However,pulse injection method requires the simpler operation and lias a higher resolution,obviously improving the measurement efficiency and bet ter displaying the details of the transfer impedance curves. 展开更多
关键词 partial discharge(PD) high frequency current transformer(HFCT) transfer impedance pulse measurement
Influence of different parameters on numerical simulation of vertical-axis marine current turbine based on OpenFOAM 预览
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作者 JI Renwei SHENG Qihu +3 位作者 SUN Ke LI Yan ZHANG Yuquan ZHANG Liang 《排灌机械工程学报》 CSCD 北大核心 2020年第4期365-371,共7页
Using the PimpleDyMFoam solver in open-source computing software OpenFOAM,based on the SST k-ωturbulence model and PIMPLE algorithm,a numerical simulation method of vertical-axis marine current turbines(VMCTs)is prop... Using the PimpleDyMFoam solver in open-source computing software OpenFOAM,based on the SST k-ωturbulence model and PIMPLE algorithm,a numerical simulation method of vertical-axis marine current turbines(VMCTs)is proposed,and the calculated results are compared with the experimental results.The results show that the numerical simulation method is feasible.Compared with other commercial softwares,this method has the advantages of higher solution efficiency and greater flexibility.According to the needs of users,the solver can be built on the basis of original code,and the corresponding discrete method can be optimized.This method can achieve optimization algorithms,save time and cost,etc.Secondly,the effects of different parameters(mesh density,time step,the selection of sidewall boundary conditions and inlet turbulence intensity)on numerical simulation of the VMCT are studied in detail.The findings summarize an effective CFD simulation strategy based on OpenFOAM and provide a valuable reference for future CFD simulations of VMCTs. 展开更多
关键词 numerical simulation hydrodynamic characteristics vertical-axis MARINE CURRENT TURBINE OPENFOAM
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Investigation and Optimization of the Current Situation of Temporary Pedestrian Crossing in Nanchang City 预览
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作者 ZENG Yan SUN Yuxi +1 位作者 XIE Kelu LU Sen 《景观研究:英文版》 2020年第2期23-25,共3页
A temporary pedestrian crossing has been set up for the first time in Nanchang City to facilitate the passage of residents,which has brought great convenience to surrounding residents and students.The author made an i... A temporary pedestrian crossing has been set up for the first time in Nanchang City to facilitate the passage of residents,which has brought great convenience to surrounding residents and students.The author made an in-depth investigation on the temporary pedestrian crossing,analyzed its advantages and existing problems through field investigation,questionnaire survey,resident interview and other forms and put forward relevant suggestions by considering the current operation mode of the facilities,to provide reference for relevant departments to optimize the temporary pedestrian crossing and provide reliable and efficient solutions for other regions. 展开更多
关键词 Nanchang City Temporary pedestrian crossing Investigation of current situation OPTIMIZATION
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