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Human intrusion detection for high-speed railway perimeter under all-weather condition 被引量:1
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作者 Pengyue Guo Tianyun Shi +1 位作者 zhen ma Jing Wang 《Railway Sciences》 2024年第1期97-110,共14页
Purpose – The paper aims to solve the problem of personnel intrusion identification within the limits of highspeed railways. It adopts the fusion method of millimeter wave radar and camera to improve the accuracy ofo... Purpose – The paper aims to solve the problem of personnel intrusion identification within the limits of highspeed railways. It adopts the fusion method of millimeter wave radar and camera to improve the accuracy ofobject recognition in dark and harsh weather conditions.Design/methodology/approach – This paper adopts the fusion strategy of radar and camera linkage toachieve focus amplification of long-distance targets and solves the problem of low illumination by laser lightfilling of the focus point. In order to improve the recognition effect, this paper adopts the YOLOv8 algorithm formulti-scale target recognition. In addition, for the image distortion caused by bad weather, this paper proposesa linkage and tracking fusion strategy to output the correct alarm results.Findings – Simulated intrusion tests show that the proposed method can effectively detect human intrusionwithin 0–200 m during the day and night in sunny weather and can achieve more than 80% recognitionaccuracy for extreme severe weather conditions.Originality/value – (1) The authors propose a personnel intrusion monitoring scheme based on the fusion ofmillimeter wave radar and camera, achieving all-weather intrusion monitoring;(2) The authors propose a newmulti-level fusion algorithm based on linkage and tracking to achieve intrusion target monitoring underadverse weather conditions;(3) The authors have conducted a large number of innovative simulationexperiments to verify the effectiveness of the method proposed in this article. 展开更多
关键词 High-speed rail perimeter Personnel invasion Object detection ALL-WEATHER Radar-camera fusion
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Analyzing the Combination Effects of Repetitive Transcranial Magnetic Stimulation and Motor Control Training on Balance Function and Gait in Patients with Stroke-Induced Hemiplegia
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作者 Xiaoqing ma zhen ma +2 位作者 Ye Xu Meng Han Hui Yan 《Proceedings of Anticancer Research》 2024年第1期54-60,共7页
Objective:To analyze the effects of repetitive transcranial magnetic stimulation combined with motor control training on the treatment of stroke-induced hemiplegia,specifically focusing on the impact on patients’bala... Objective:To analyze the effects of repetitive transcranial magnetic stimulation combined with motor control training on the treatment of stroke-induced hemiplegia,specifically focusing on the impact on patients’balance function and gait.Methods:Fifty-two cases of hemiplegic stroke patients were randomly divided into two groups,26 in the control group and 26 in the observation group,using computer-generated random grouping.All participants underwent conventional treatment and rehabilitation training.In addition to these,the control group received repetitive transcranial magnetic pseudo-stimulation therapy+motor control training,while the observation group received repetitive transcranial magnetic stimulation therapy+motor control training.The balance function and gait parameters of both groups were compared before and after the interventions and assessed the satisfaction of the interventions in both groups.Results:Before the invention,there were no significant differences in balance function scores and each gait parameter between the two groups(P>0.05).However,after the intervention,the observation group showed higher balance function scores compared to the control group(P<0.05).The observation group also exhibited higher step speed and step frequency,longer step length,and a higher overall satisfaction level with the intervention compared to the control group(P<0.05).Conclusion:The combination of repetitive transcranial magnetic stimulation and motor control training in the treatment of stroke-induced hemiplegia has demonstrated positive effects.It not only improves the patient’s balance function and gait but also contributes to overall physical rehabilitation. 展开更多
关键词 Stroke-induced hemiplegia Repetitive transcranial magnetic stimulation Motor control training Balance function GAIT
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Study on the Effect of Repetitive Peripheral Magnetic Stimulation Combined with Conventional Rehabilitation Measures on Shoulder Dysfunction in Early Stroke
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作者 Hui Yan Mingmei Ding +2 位作者 Ye Xu zhen ma Xiaoqing ma 《Journal of Clinical and Nursing Research》 2024年第2期44-49,共6页
Objective:To study the effect of repetitive peripheral magnetic stimulation(rPMS)combined with conventional rehabilitation measures on shoulder dysfunction in early stroke.Methods:60 patients with shoulder dysfunction... Objective:To study the effect of repetitive peripheral magnetic stimulation(rPMS)combined with conventional rehabilitation measures on shoulder dysfunction in early stroke.Methods:60 patients with shoulder dysfunction in early stroke were selected,and all of them were admitted to our hospital from August 2021 to August 2023.The patients were randomly grouped into a control group(conventional rehabilitation measures intervention,30 cases)and an intervention group(rPMS and conventional rehabilitation measures intervention,30 cases)according to the lottery method.The pain scores,shoulder mobility,and motor function scores of the two groups were compared.Results:The pain score was lower in the intervention group,and the shoulder mobility and motor function scores were higher in the intervention group(P<0.05)as compared to that of the control group.Conclusion:The effect of combining rPMS and conventional rehabilitation measures in treating shoulder dysfunction in early stroke was remarkable and should be popularized. 展开更多
关键词 Repetitive peripheral magnetic stimulation Conventional rehabilitation measures Early stroke Shoulder joint function
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High performance SiC trench-type MOSFET with an integrated MOS-channel diode 被引量:1
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作者 魏杰 姜钦峰 +5 位作者 罗小蓉 黄俊岳 杨可萌 马臻 方健 杨霏 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第2期519-524,共6页
A novel SiC double-trench metal-oxide-semiconductor field effect transistor(MOSFET) with integrated MOS-channel diode is proposed and investigated by Sentaurus TCAD simulation. The new SiC MOSFET has a trench gate and... A novel SiC double-trench metal-oxide-semiconductor field effect transistor(MOSFET) with integrated MOS-channel diode is proposed and investigated by Sentaurus TCAD simulation. The new SiC MOSFET has a trench gate and a stepped-trench source, and features an integrated MOS-channel diode on the top sidewall of the source trench(MT MOS). In the reverse conduction state, the MOS-channel diode turns on firstly to prevent the internal parasitic body diode being activated, and thus reduces the turn-on voltage VFand suppresses the bipolar degradation phenomena. The VFof1.70 V(@Ids=-100 A/cm^(2)) for the SiC MT MOS is 38.2% lower than that of SiC double-trench MOSFET(DT MOS).Meanwhile, the reverse recovery charge Qrrof the MT MOS is 58.7% lower than that of the DT MOS at Iload= 700 A/cm^(2),and thus the reverse recovery loss is reduced. Furthermore, owing to the modulation effect induced by the double trenches,the MT MOS preserves the same superior forward conduction and blocking performance as those of DT MOS, with 22.9% and 18.2% improvement on breakdown voltage and RON,spcompared to the trench gate MOSFET with planar integrated SBD(ST MOS). 展开更多
关键词 SiC MOSFET bipolar degradation MOS-channel diode reverse recovery
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Highly reinforce the interface stability using 2-Phenyl-1H-imidazole-1-sulfonate electrolyte additive to enhance the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite batteries
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作者 Xin He Yiting Li +8 位作者 Wenlian Wang Xueyi Zeng Huilin Hu Haijia Li Weizhen Fan Chaojun Fan Jian Cai zhen ma Junmin Nan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2023年第5期10-22,I0001,共14页
This work develops 2-Phenyl-1H-imidazole-1-sulfonate(PHIS)as a multi-functional electrolyte additive for H2O/HF scavenging and film formation to improve the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_... This work develops 2-Phenyl-1H-imidazole-1-sulfonate(PHIS)as a multi-functional electrolyte additive for H2O/HF scavenging and film formation to improve the high temperature performance of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite batteries.After 450 cycles at room temperature(25℃),the discharge capacity retentions of batteries with blank and PHIS-containing electrolyte are 56.03%and 94.92%respectively.After 230 cycles at high temperatures(45℃),their values are 75.30%and 88.38%respectively.The enhanced electrochemical performance of the batteries with PHIS-containing electrolyte is supported by the spectroscopic characterization and theoretical calculations.It is demonstrated that this PHIS electrolyte additive can facilitate the construction of the electrode interface films,remove the H2O/HF in the electrolyte,and improve the electrochemical performance of the batteries.This work not only develops a sulfonate-based electrolyte but also can stimulate new ideas of functional additives to improve the battery performance. 展开更多
关键词 LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)/graphite battery High temperature performance H_(2)O/HF scavenger 2-Phenyl-1H-imidazole-1-sulfonate Electrolyte additive
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Causal role of immune cells in obstructive sleep apnea hypopnea syndrome:Mendelian randomization study 被引量:1
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作者 Huang-Hong Zhao zhen ma Dong-Sheng Guan 《World Journal of Clinical Cases》 SCIE 2024年第7期1227-1234,共8页
BACKGROUND Despite being one of the most prevalent sleep disorders,obstructive sleep apnea hypoventilation syndrome(OSAHS)has limited information on its immunologic foundation.The immunological underpinnings of certai... BACKGROUND Despite being one of the most prevalent sleep disorders,obstructive sleep apnea hypoventilation syndrome(OSAHS)has limited information on its immunologic foundation.The immunological underpinnings of certain major psychiatric diseases have been uncovered in recent years thanks to the extensive use of genome-wide association studies(GWAS)and genotyping techniques using highdensity genetic markers(e.g.,SNP or CNVs).But this tactic hasn't yet been applied to OSAHS.Using a Mendelian randomization analysis,we analyzed the causal link between immune cells and the illness in order to comprehend the immunological bases of OSAHS.AIM To investigate the immune cells'association with OSAHS via genetic methods,guiding future clinical research.METHODS A comprehensive two-sample mendelian randomization study was conducted to investigate the causal relationship between immune cell characteristics and OSAHS.Summary statistics for each immune cell feature were obtained from the GWAS catalog.Information on 731 immune cell properties,such as morphologic parameters,median fluorescence intensity,absolute cellular,and relative cellular,was compiled using publicly available genetic databases.The results'robustness,heterogeneity,and horizontal pleiotropy were confirmed using extensive sensitivity examination.RESULTS Following false discovery rate(FDR)correction,no statistically significant effect of OSAHS on immunophenotypes was observed.However,two lymphocyte subsets were found to have a significant association with the risk of OSAHS:Basophil%CD33dim HLA DR-CD66b-(OR=1.03,95%CI=1.01-1.03,P<0.001);CD38 on IgD+CD24-B cell(OR=1.04,95%CI=1.02-1.04,P=0.019).CONCLUSION This study shows a strong link between immune cells and OSAHS through a gene approach,thus offering direction for potential future medical research. 展开更多
关键词 Obstructive sleep apnea hypopnea syndrome IMMUNITY Causal inference MR analysis Sensitivity
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Planning and construction of Xiong’an New Area(city of over 5 million people):Contributions of China’s geologists and urban geology
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作者 Bo Han zhen ma +9 位作者 Liang-jun Lin Hong-wei Liu Yi-hang Gao Yu-bo Xia Hai-tao Li Xu Guo Feng ma Yu-shan Wang Ya-long Zhou Hong-qiang Li 《China Geology》 CAS CSCD 2024年第3期382-408,共27页
China established Xiong’an New Area in Hebei Province in 2017,which is planned to accommodate about 5 million people,aiming to relieve Beijing City of the functions non-essential to its role as China’s capital and t... China established Xiong’an New Area in Hebei Province in 2017,which is planned to accommodate about 5 million people,aiming to relieve Beijing City of the functions non-essential to its role as China’s capital and to expedite the coordinated development of the Beijing-Tianjin-Hebei region.From 2017 to 2021,the China Geological Survey(CGS)took the lead in multi-factor urban geological surveys involving space,resources,environments,and disasters according to the general requirements of“global vision,international standards,distinctive Chinese features,and future-oriented goals”in Xiong’an New Area,identifying the engineering geologic conditions and geologic environmental challenges of this area.The achievements also include a 3D engineering geological structure model for the whole area,along with“one city proper and five clusters”,insights into the ecology and the background endowment of natural resources like land,geothermal resources,groundwater,and wetland of the area before engineering construction,a comprehensive monitoring network of resources and environments in the area,and the“Transparent Xiong’an”geological information platform that is open,shared,dynamically updated,and three-dimensionally visualized.China’s geologists and urban geology have played a significant role in the urban planning and construction of Xiong’an New Area,providing whole-process geological solutions for urban planning,construction,operation and management.The future urban construction of Xiong’an New Area will necessitate the theoretical and technical support of earth system science(ESS)from various aspects,and the purpose is to enhance the resilience of the new type of city and to provide support for the green,low-carbon,and sustainable development of this area. 展开更多
关键词 Low Carbon New City Planning and construction Land Geothermal resources Groundwater Wetland Underground space Geologic disasters Site stability Natural resource Ecosystem Geological safety Transparent Xiong’an Resilient city Xiong’an New Area
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Eliminating H_(2)O/HF and regulating interphase with bifunctional tolylene-2,4-diisocyanate(TDI)additive for long life Li-ion battery
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作者 Xueyi Zeng Xiang Gao +8 位作者 Peiqi Zhou Haijia Li Xin He Weizhen Fan Chaojun Fan Tianxiang Yang zhen ma Xiaoyang Zhao Junmin Nan 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第8期519-528,I0011,共11页
Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challengi... Lithium-ion batteries(LIBs)featuring a Ni-rich cathode exhibit increased specific capacity,but the establishment of a stable interphase through the implementation of a functional electrolyte strategy remains challenging.Especially when the battery is operated under high temperature,the trace water present in the electrolyte will accelerate the hydrolysis of the electrolyte and the resulting HF will further erode the interphase.In order to enhance the long-term cycling performance of graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)(NCM811)LIBs,herein,Tolylene-2,4-diisocyanate(TDI)additive containing lone-pair electrons is employed to formulate a novel bifunctional electrolyte aimed at eliminating H_(2)O/HF generated at elevated temperature.After 1000 cycles at 25℃,the battery incorporating the TDI-containing electrolyte exhibits an impressive capacity retention of 94%at 1 C.In contrast,the battery utilizing the blank electrolyte has a lower capacity retention of only 78%.Furthermore,after undergoing 550 cycles at 1 C under45℃,the inclusion of TDI results in a notable enhancement of capacity,increasing it from 68%to 80%.This indicates TDI has a favorable influence on the cycling performance of LIBs,especially at elevated temperatures.The analysis of the film formation mechanism suggests that the lone pair of electrons of the isocyanate group in TDI play a crucial role in inhibiting the generation of H_(2)O and HF,which leads to the formation of a thin and dense interphase.The existence of this interphase is thought to substantially enhance the cycling performance of the LIBs.This work not only improves the performance of graphite/NCM811 batteries at room temperature and high temperature by eliminating H_(2)O/HF but also presents a novel strategy for advancing functional electrolyte development. 展开更多
关键词 Graphite/LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)battery Tolylene-2 4-diisocyanate Long-cycling performance H_(2)O/HF eliminated additive
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Effect of copper precursors on the catalytic performance of Cu-ZSM-5 catalysts in N2O decomposition 被引量:4
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作者 Tao Meng Nan Ren zhen ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第5期1051-1058,共8页
Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5 (Si/Al ratio = 15) with aqueous solutions of differ- ent Cu precursors (CuCl2, Cu(NO3)2, CuSO4, Cu(CH3COO)2, and ammoniacal copper (II) complex ion)... Five Cu-ZSM-5 catalysts were obtained by treating Na-ZSM-5 (Si/Al ratio = 15) with aqueous solutions of differ- ent Cu precursors (CuCl2, Cu(NO3)2, CuSO4, Cu(CH3COO)2, and ammoniacal copper (II) complex ion). After being pretreated in flowing He at 500 ℃ to form active Cu+, these catalysts exhibited quite different activities in cata- lytic decomposition of N2O. CZM-AC(II) (prepared by ammoniacal copper (II) complex ion) with 9.4 wt% Cu con- tent was the most active among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 400 ℃. CZM-CA (prepared using Cu( CH3COO)2 as the Cu precursor) with 2.8 wt% Cu content was the second most active catalyst among these Cu-ZSM-5 catalysts, achieving almost complete N2I conversion at 425 ℃. CZM-CC, CZM- CN, and CZM-CS prepared by using CuCl2, Cu(NO3)2, or CuSO4 as the Cu precursor with similar Cu contents (≈1.7 wt%) were the least active among these Cu-ZSM-5 catalysts, achieving ca. 90% N2O conversion at 500 ℃. XRD, ICP, SEM, TEM, EDX-mapping, and CO-IR experiments were conducted to characterize relevant samples. The superior activity of CZM-AC(II) can be attributed to the high contents of total Cu+ and dimeric Cu+ among these samples. The influence of co-fed O2 or H2O on the catalytic performance of typical samples was also studied. 展开更多
关键词 Copper precursor CU-ZSM-5 N2O decomposition CATALYSIS Catalyst ZEOLITE
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Porous g-C3N4 with enhanced adsorption and visible-light photocatalytic performance for removing aqueous dyes and tetracycline hydrochloride 被引量:3
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作者 Junlei Zhang zhen ma 《Chinese Journal of Chemical Engineering》 SCIE EI CAS CSCD 2018年第4期753-760,共8页
Porous g-C3N4samples were obtained by simply calcining bulk g-C3N4in static air in a muffle oven.The photocatalytic performance of these samples was evaluated through the removal of aqueous organic dyes(methylene blu... Porous g-C3N4samples were obtained by simply calcining bulk g-C3N4in static air in a muffle oven.The photocatalytic performance of these samples was evaluated through the removal of aqueous organic dyes(methylene blue and methyl orange)and tetracycline hydrochloride under visible-light irradiation(λ〉420 nm).Compared to bulk g-C3N4,porous g-C3N4exhibited much better capability for removing these contaminants,especially under visible-light irradiation,due to the enlarged specific surface area and more efficient separation of photogenerated charge carries.In particular,porous g-C3N4obtained by calcining bulk g-C3N4in air at 525℃ showed the highest visible-light-driven catalytic activity among these samples.Superoxide radical anions(·O2^-)were found to be the primary active species responsible for photodegradation. 展开更多
关键词 C3N4 Catalyst Reaction Waste treatment Dyes Tetracycline hydrochloride
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Top-down synthesis strategies: Maximum noble-metal atom efficiency in catalytic materials 被引量:1
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作者 Yaxin Chen Zhiwei Huang +3 位作者 Xiao Gu zhen ma Jianmin Chen Xingfu Tang 《Chinese Journal of Catalysis》 CSCD 北大核心 2017年第9期1588-1596,共9页
Top‐down synthesis has been used to prepare catalytic materials with nanometer sizes,but fabricating atomically dispersed metal catalysts remains a challenge because surface single metal atoms are prone to aggregatio... Top‐down synthesis has been used to prepare catalytic materials with nanometer sizes,but fabricating atomically dispersed metal catalysts remains a challenge because surface single metal atoms are prone to aggregation or coalescence.A top‐down strategy is used to synthesize atomically dispersed metal catalysts,based on supported Ag nanoparticles.The changes of the geometric and electronic structures of the Ag atoms during the top‐down process are studied using the in situ synchrotron X‐ray diffraction technique,ex situ X‐ray absorption spectroscopy,and transmission electron microscopy.The experimental results,coupled with the density functional theory calculations,demonstrate that the electronic perturbation of the Ag frontier orbitals,induced by the Ag‐O interactions at the perimeter of the metal‐support interface,is the driving force of the top‐down process.The top‐down synthesis has two important functions:to increase the number of catalytic active sites and to facilitate the study of complex reaction mechanisms(e.g.,formaldehyde oxidation)by developing single‐site model catalysts. 展开更多
关键词 Top‐down synthesis Atomic dispersion Catalytic active site Electronic metal‐support interaction Formaldehyde oxidation
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Design and Initial Testing of An Integrated Switched Reluctance Starter/Generator System for Unmanned Aerial Vehicle 被引量:1
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作者 Erxin Zhao Shoujun Song +3 位作者 zhen ma Xueping Zhang Le Ning Yang Liu 《CES Transactions on Electrical Machines and Systems》 2018年第4期377-383,共7页
According to specific performance requirements,an integrated switched reluctance starter/generator system,which can start the engine and supply electrical energy to the loads,is designed and manufactured for the unman... According to specific performance requirements,an integrated switched reluctance starter/generator system,which can start the engine and supply electrical energy to the loads,is designed and manufactured for the unmanned aerial vehicle.Considering the required starting torque and speed range,the geometrical dimensions of the switched reluctance machine are calculated based on the output equation and further optimized with finite element analysis,and the flux-linkage,inductance and static torque characteristics are illustrated.To verify the performances of the designed system,detailed simulation with the model considering piston engine and experiment using the test bench are carried out. 展开更多
关键词 Integrated starter/generator system switched reluctance machine(SRM) unmanned aerial vehicle(UAV)
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Evidence for Magnetic Fractional Excitations in a Kitaev Quantum-Spin-Liquid Candidate α-RuCl_(3)
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作者 Kejing Ran Jinghui Wang +12 位作者 Song Bao zhengwei Cai Yanyan Shangguan zhen ma Wei Wang Zhao-Yang Dong P.Cermak A.Schneidewind Siqin Meng Zhilun Lu Shun-Li Yu Jian-Xin Li Jinsheng Wen 《Chinese Physics Letters》 SCIE EI CAS CSCD 2022年第2期72-77,共6页
It is known that α-RuCl_(3) has been studied extensively because of its proximity to the Kitaev quantum-spin-liquid(QSL)phase and the possibility of approaching it by tuning the competing interactions.Here we present... It is known that α-RuCl_(3) has been studied extensively because of its proximity to the Kitaev quantum-spin-liquid(QSL)phase and the possibility of approaching it by tuning the competing interactions.Here we present the first polarized inelastic neutron scattering study on α-RuCl_(3) single crystals to explore the scattering continuum around the Γ point at the Brillouin zone center,which was hypothesized to be resulting from the Kitaev QSL state but without concrete evidence.With polarization analyses,we find that,while the spin-wave excitations around the Γ point vanish above the transition temperature T_(N),the pure magnetic continuous excitations around the Γ point are robust against temperature.Furthermore,by calculating the dynamical spin-spin correlation function using the cluster perturbation theory,we derive magnetic dispersion spectra based on the K-Γ model,which involves with a ferromagnetic Kitaev interaction of −7.2 meV and an off-diagonal interaction of 5.6 meV.We find this model can reproduce not only the spin-wave excitation spectra around the Γ point,but also the non-spin-wave continuous magnetic excitations around the Γ point.These results provide evidence for the existence of fractional excitations around the Γ point originating from the Kitaev QSL state,and further support the validity of the K-Γ model as the effective minimal spin model to describe α-RuCl_(3). 展开更多
关键词 temperature EXCITATION DIAGONAL
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Recent progress on magnetic-field studies on quantum-spin-liquid candidates
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作者 zhen ma Kejing Ran +4 位作者 Jinghui Wang Song Bao zhengwei Cai Shichao Li Jinsheng Wen 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第10期1-14,共14页
Quantum spin liquids(QSLs) represent a novel state of matter in which quantum fluctuations prevent the conventional magnetic order from being established, and the spins remain disordered even at zero temperature. Th... Quantum spin liquids(QSLs) represent a novel state of matter in which quantum fluctuations prevent the conventional magnetic order from being established, and the spins remain disordered even at zero temperature. There have been many theoretical developments proposing various QSL states. On the other hand, experimental movement was relatively slow largely due to limitations on the candidate materials and difficulties in the measurements. In recent years, the experimental progress has been accelerated. In this topical review, we give a brief summary of experiments on the QSL candidates under magnetic fields. We arrange our discussions by two categories: i) Geometrically-frustrated systems, including triangularlattice compounds YbMgGaO4 and YbZnGaO4, κ-(BEDT-TTF)2 Cu2(CN)3, and EtMe3 Sb[Pd(dmit)2]2, and the kagom′e system ZnCu3(OH)6 Cl2; ii) the Kitaev material α-RuCl3. Among these, we will pay special attention to α-RuCl3, which has been intensively studied by ours and other groups recently. We will present evidence that both supports and rejects the QSL ground state for these materials, based on which we give several perspectives to stimulate further research activities. 展开更多
关键词 quantum spin liquids spin glass neutron scattering
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Distribution and Pollution Assessment of Heavy Metals in Beidaihe Near-Shore Marine Sediments
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作者 Hongwei Liu zhen ma 《Journal of Materials Science and Chemical Engineering》 2015年第12期1-7,共7页
The concentrations of heavy metals, Cd, Hg, Pb, Cu and As in marine sediments from 138 sites located in the Beidaihe near-shore area of Bohai bay, were analyzed to find out the distribution characteristics of these he... The concentrations of heavy metals, Cd, Hg, Pb, Cu and As in marine sediments from 138 sites located in the Beidaihe near-shore area of Bohai bay, were analyzed to find out the distribution characteristics of these heavy metals. Potential Ecological Risk index were adopted to assess the heavy metals contamination, and the assessment results indicated that the content of heavy metals in this area is in a low to moderate level, while high values were found in the southwest and northeast region, and the value in the middle region is comparatively low. The high pollution hazard sites were close to the Renzaohe estuary and Shihe estuary and the high risk is mainly led by Hg. 展开更多
关键词 HEAVY Metals Marine SEDIMENTS DISTRIBUTION CONTAMINATION Assessment Beidaihe
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角膜生物力学分析仪评估SMILE与FS-LASIK术后角膜生物力学的变化 被引量:1
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作者 李文静 刘洋 +5 位作者 王政来 张金金 马臻 周玲婕 蔡博 庄文娟 《国际眼科杂志》 CAS 北大核心 2023年第11期1793-1797,共5页
目的:利用角膜生物力学分析仪(Corvis ST)评估行飞秒激光小切口角膜基质透镜取出术(SMILE)和飞秒激光辅助的准分子激光原位角膜磨镶术(FS-LASIK)治疗的中度屈光不正患者术后角膜生物力学的变化特征。方法:前瞻性队列研究。选取2020-11/2... 目的:利用角膜生物力学分析仪(Corvis ST)评估行飞秒激光小切口角膜基质透镜取出术(SMILE)和飞秒激光辅助的准分子激光原位角膜磨镶术(FS-LASIK)治疗的中度屈光不正患者术后角膜生物力学的变化特征。方法:前瞻性队列研究。选取2020-11/2021-11在宁夏眼科医院视光中心拟行角膜屈光手术的中度近视患者65例130眼,考虑双眼存在关联,双眼同时满足条件选右眼进行研究,其中SMILE组30眼,FS-LASIK组35眼。应用Corvis ST观察两组患者术前、术后1、3mo角膜生物力学参数综合半径(IR)、反向凹面半径(ICR)、形变幅度比值(DAR2)、硬度指数(SP-A1)、相关厚度-水平方向(ARTh)和最大压陷曲率半径(HC-Radius)的变化。结果:两组间患者术前,术后1、3mo生物力学参数比较均无差异(P>0.05)。各组患者术后1、3mo IR、ICR、DAR2均较术前明显增加,SP-A1、ARTh、HC-Radius均较术前明显降低(均P<0.05),术后1mo与术后3mo生物力学参数比较无差异(P>0.05)。两组患者术后3mo中央角膜厚度(CCT)与ARTh和SP-A1呈正相关(FS-LASIK组:r=0.727、0.819,SMLIE组:r=0.683、0.434,均P<0.05),与IR和ICR呈负相关(FS-LASIK组:r=-0.697、-0.622,SMLIE组:r=-0.447、-0.491,均P<0.05)。结论:对于中度近视患者,SMILE和FS-LASIK术后均可导致角膜生物力学稳定性降低,两种手术方式对生物力学的影响无明显差异,且在术后1mo时生物力学趋于稳定,术后CCT与生物力学参数ARTh、SP-A1、IR和ICR存在相关性。 展开更多
关键词 飞秒激光小切口角膜基质透镜取出术(SMILE) 飞秒激光辅助的准分子激光原位角膜磨镶术(FS-LASIK) 角膜生物力学 角膜生物力学分析仪
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超微电极实验:基本原理、制备方法和伏安性能 被引量:1
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作者 马桢 林佳阳 +2 位作者 南文静 韩联欢 詹东平 《电化学》 CAS 北大核心 2023年第7期16-20,共5页
超微电极的电极尺寸小,双电层电容小,IR降小,传质速率快,响应快,信噪比高,兼具时间和空间分辨率,不仅可以研究快速电极反应动力学性质,而且可以作为电化学扫描显微镜探针,实现基底反应活性的成像,在电化学各个领域均有重要应用,成为一... 超微电极的电极尺寸小,双电层电容小,IR降小,传质速率快,响应快,信噪比高,兼具时间和空间分辨率,不仅可以研究快速电极反应动力学性质,而且可以作为电化学扫描显微镜探针,实现基底反应活性的成像,在电化学各个领域均有重要应用,成为一种重要的电化学实验方法。本文将扼要介绍超微电极的基本原理、简易的制备方法及伏安性能的表征实验,以期对开展超微电极实验研究的电化学工作者有所裨益。 展开更多
关键词 超微电极 电极制备 伏安特性
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Influence of underground space development mode on the groundwater flow field in Xiong’an new area 被引量:3
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作者 Yi-hang Gao Jun-hui Shen +4 位作者 Lin Chen Xiao Li Shuang Jin zhen ma Qing-hua Meng 《Journal of Groundwater Science and Engineering》 2023年第1期68-80,共13页
The degree and scale of underground space development are growing with the continuous advancement of urbanization in China.The lack of research on the change of the groundwater flow field before and after the developm... The degree and scale of underground space development are growing with the continuous advancement of urbanization in China.The lack of research on the change of the groundwater flow field before and after the development of underground space has led to various problems in the process of underground space development and operation.This paper took the key development zone of the Xiong’an New Area as the study area,and used the Groundwater modeling system software(GMS)to analyse the influence on the groundwater flow field under the point,line,and surface development modes.The main results showed that the underground space development would lead to the expansion and deepening of the cone of depression in the aquifer.The groundwater level on the upstream face of the underground structure would rise,while the water level on the downstream face would drop.The“line”concurrent development has the least impact on the groundwater flow field,and the maximum rise of water level on the upstream side of the underground structure is expected to be approximately 3.05 m.The“surface”development has the greatest impact on the groundwater flow field,and the maximum rise of water level is expected to be 7.17 m. 展开更多
关键词 Xiong’an new area Groundwater flow field Underground space GMS
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池沸腾加热器换热优化设计——基于Boltzmann方法研究并选取加热器最优参数
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作者 王恺文 魏亚明 +3 位作者 马震 廖必成 王明骏 娄钦 《建模与仿真》 2024年第4期4348-4360,共13页
本文采用了相变格子Boltzmann模型研究加热器高度、长度、表面润湿性和表面结构对池沸腾换热性能的影响。我们发现加热器高度较低时汽液相变速度更大,因此加热器高度越低热流密度越大。另一方面,加热器长度越短,换热性能越好;其次,在低... 本文采用了相变格子Boltzmann模型研究加热器高度、长度、表面润湿性和表面结构对池沸腾换热性能的影响。我们发现加热器高度较低时汽液相变速度更大,因此加热器高度越低热流密度越大。另一方面,加热器长度越短,换热性能越好;其次,在低过热度下全疏水加热器换热性能最好,而在高过热度下全亲水换热器性能则更好;最后,我们还研究了加热器表面微结构的影响,发现锥形表面加热器的换热性能要优于光滑表面加热器。 展开更多
关键词 大容器饱和沸腾 加热器 格子BOLTZMANN方法
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多维测度下高校大学生劳动教育的实效研究——基于甘肃省高校样本数据的实证分析
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作者 马真 赵华 +2 位作者 包一婷 罗洁 赵亚飞 《管理科学与研究(中英文版)》 2023年第10期44-49,共6页
党的十八大以来,习近平总书记高度重视青少年劳动教育,强调“把劳动教育纳入人才培养全过程,贯通大中小学各学段和家庭、学校、社会各方面”。本研究以甘肃省高校为研究对象,选取大学生劳动技能综合熟练度、劳动参与综合意愿度、劳动综... 党的十八大以来,习近平总书记高度重视青少年劳动教育,强调“把劳动教育纳入人才培养全过程,贯通大中小学各学段和家庭、学校、社会各方面”。本研究以甘肃省高校为研究对象,选取大学生劳动技能综合熟练度、劳动参与综合意愿度、劳动综合频率与劳动综合时长为研究维度提出假设。基于研究假设构建模型,通过信效度检验与因子分析(探索性因子和验证性因子)后分析模型拟合程度,得出结论:劳动技能综合熟练度、劳动参与综合意愿度、劳动综合频率、劳动综合时长四个维度之间对于高校大学生劳动教育的实效存在显著正相关性。并对其他样本数据相关性分析后得出:性别、年级、户口类别对于大学生劳动教育的实效具有显著性,并剖析其原因。最后针对以上研究结论从家庭、学校、社会提出对策,以期为高校劳动教育提供经验参考。 展开更多
关键词 高校大学生 劳动教育 甘肃省 实效
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