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Aerodynamic actuation characteristics of radio-frequency discharge plasma and control of supersonic flow
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作者 杨臻 宋慧敏 +3 位作者 王宏宇 郭善广 贾敏 王康 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期321-330,共10页
In this paper, aerodynamic actuation characteristics of radio-frequency(RF) discharge plasma are studied and a method is proposed for shock wave control based on RF discharge. Under the static condition, a RF diffuse ... In this paper, aerodynamic actuation characteristics of radio-frequency(RF) discharge plasma are studied and a method is proposed for shock wave control based on RF discharge. Under the static condition, a RF diffuse glow discharge can be observed;under the supersonic inflow, the plasma is blown downstream but remains continuous and stable.Time-resolved schlieren is used for flow field visualization. It is found that RF discharge not only leads to continuous energy deposition on the electrode surface but also induces a compression wave. Under the supersonic inflow condition, a weak oblique shock wave is induced by discharge. Experimental results of the shock wave control indicate that the applied actuation can disperse the bottom structure of the ramp-induced oblique shock wave, which is also observed in the extracted shock wave structure after image processing. More importantly, this control effect can be maintained steadily due to the continuous high-frequency(MHz) discharge. Finally, correlations for schlieren images and numerical simulations are employed to further explore the flow control mechanism. It is observed that the vortex in the boundary layer increases after the application of actuation, meaning that the boundary layer in the downstream of the actuation position is thickened. This is equivalent to covering a layer of low-density smooth wall around the compression corner and on the ramp surface, thereby weakening the compressibility at the compression corner. Our results demonstrate the ability of RF plasma aerodynamic actuation to control the supersonic airflow. 展开更多
关键词 radio-frequency(RF) DISCHARGE PLASMA surface DISCHARGE FLOW control aerodynamic ACTUATION
Relation between etching profile and voltage-current shape of sintered SiC etching by atmospheric pressure plasma
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作者 D C SEOK S R YOO +2 位作者 K I LEE Y S CHOI Y H JUNG 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第4期137-144,共8页
Sintered silicon carbide(SiC)was etched by a dielectric barrier discharge source.A high voltage bipolar pulse was used with helium gas for the plasma generation.One stable filament plasma was generated and could be us... Sintered silicon carbide(SiC)was etched by a dielectric barrier discharge source.A high voltage bipolar pulse was used with helium gas for the plasma generation.One stable filament plasma was generated and could be used for SiC etching.As the processing gas(NF3)mixing rate increased,the width and depth of the etching profile became narrower and deeper.The differentiated V-Q Lissajous method was used for measuring the capacitances(Ceq)of the electrode after the plasma turned on.The width of the etching profile was proportional to Ceq.As the current peak value/smx of the substrate current in creased,the volume removal rate of SiC increased.The etch depth was proportional to the ratio of/smx to Ceq.Additionally,because of the different characteristics of the plasma disks on SiC substrate by the voltage polarity,the etching profile was unstable.However,in high NF3 mixing process,the etching profile became stable and deeper. 展开更多
关键词 dielectric BARRIER DISCHARGE silicon CARBIDE plasma etching、filament discharge surface charge
隧道砂层段排水性能对水压与排水量的影响 预览
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作者 刁钰 贾镇阳 +3 位作者 李光帅 褚振西 高泽东 郭勇志 《水利水电技术》 北大核心 2019年第4期23-31,共9页
为保证运营期某隧道衬砌结构安全提供理论依据,需提出排水量与衬砌水压荷载之间的关系。通过ABAQUS数值模拟软件,将模型中隧道排水系统和初支统一视为一层排水介质,简化为一维第三类边界条件,并利用温度场与渗流场的对应关系,使用温度... 为保证运营期某隧道衬砌结构安全提供理论依据,需提出排水量与衬砌水压荷载之间的关系。通过ABAQUS数值模拟软件,将模型中隧道排水系统和初支统一视为一层排水介质,简化为一维第三类边界条件,并利用温度场与渗流场的对应关系,使用温度场模拟渗流场,在保证精度的同时,极大的提高了计算效率。对数值模拟出的变量关系进行曲线拟合,以得到简化计算公式。研究表明,对于本工程,流量与水压1个月内迅速下降并稳定。初支渗透性减小,隧道压力水头增加。当表面渗透系数K≤3×10^-5 d^-1时,可认为初支不透水,承担全部水压;当K≥3 d^-1时,可认为初支完全透水,不承担水压力,不影响隧道排水;当表面渗透系数3×10^-5≤K≤3 d^-1时,稳定水头高于设计水头,承担部分水压力。拟合公式可以合理反应表面渗透系数、水头、排水量、时间的相互关系。 展开更多
关键词 隧道 砂层 排水量 水头 数值模拟 渗流场 堵水限排
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Study on the discharge mechanism and EM radiation characteristics of Trichel pulse discharge in air
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作者 王闯 陈曦 +1 位作者 唐凯 李鹏斐 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第5期113-120,共8页
The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM)radiation signals.In this paper,the discharge mechanism and radiation characteristics of the Trichel p... The Trichel pulse stage is an unstable stage of negative corona discharge that can also involve electromagnetic(EM)radiation signals.In this paper,the discharge mechanism and radiation characteristics of the Trichel pulse are studied in the needle-plate electrode configuration.The Trichel pulse currenl and its EM radiation signals are measured at different applied voltages.The results show that Trichel pulse discharge changes from the nindom pulse stage to the continuous pulse stage as the applied voltage increases.During these different stages,the normalized shape of the Trichel pulses remains unchanged,while the frequency of the EM radiation generated by the discharge remains unchanged.The discharge mechanism and EM radiation characteristics of the Trichel pulse are theoretically analyzed in the different stages.Both the positive ion sheath and the negative ion cloud play key roles in the formation of the Trichel pulse.The EM radiati on signal is generated by the rapidly changing Trichel pulse current,and the Trichel pulse current waveform determines the characteristics of the EM radiation signal. 展开更多
关键词 NEGATIVE CORONA DISCHARGE Trichel PULSE EM RADIATION DISCHARGE mechanism
Experimental study of rotating gliding arc discharge plasma-assisted combustion in an aero-engine combustion chamber
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作者 Liming HE Yi CHEN +3 位作者 Jun DENG Jianping LEI Li FEI Pengfei LIU 《中国航空学报:英文版》 SCIE EI CAS CSCD 2019年第2期337-346,共10页
The combustion chamber is the core component of an aero-engine, and affects its reliability and security operation, even the performance of the aircraft. In this work, a Plasma-Assisted Combustion(PAC) test platform w... The combustion chamber is the core component of an aero-engine, and affects its reliability and security operation, even the performance of the aircraft. In this work, a Plasma-Assisted Combustion(PAC) test platform was developed to validate the feasibility of using PAC actuators to enhance annular combustor performance. Two plans of PAC(rotating gliding arc discharge plasma) were designed, Assisted Combustion from Primary Holes(ACPH) and Assisted Combustion from Dilution Holes(ACDH). Comparative experiments and analysis between conventional combustion and PAC were conducted to study the effects of ACPH and ACDH on the performances including average outlet temperature, combustion efficiency, pattern factor under four different excessive air coefficients(0.8, 1, 2, and 4), and lean blowout performance at different inlet airflow velocities. Experimental results show that the combustion efficiency is improved after PAC compared with that in normal conditions, and the combustion efficiency of ACPH increases2.45%, 1.49%, 1.04%, and 0.47%, while it increases 2.75%, 1.67%, 1.36%, and 0.36% under ACDH conditions. The uniformity of the outlet temperature field and the lean blowout performance are improved after PAC. Especially for ACPH, the widening of the lean blowout limit is8.3%, 12.4%, 12.8%, and 25% respectively when the inlet velocity ranges from 60 m/s to120 m/s. These results offer new perspectives for using PAC devices to enhance aero-engine combustors’ performances. 展开更多
关键词 AERO-ENGINE Assisted COMBUSTION ACTUATOR COMBUSTION CHAMBERS Plasma-Assisted COMBUSTION ROTATING GLIDING arc discharge
The effects of gas flow pattern on the generation of ozone in surface dielectric barrier discharge
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作者 谢松汝 何勇 +4 位作者 袁定琨 王智化 Sunel KUMAR 朱燕群 岑可法 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第5期168-178,共11页
Ozone production utilizing surface dielectric barrier discharge(SDBD)was experimental studied for different flow patterns considering the influences of transversal flow,lateral flow and different lateral flow position... Ozone production utilizing surface dielectric barrier discharge(SDBD)was experimental studied for different flow patterns considering the influences of transversal flow,lateral flow and different lateral flow positions.Results show that the flow patterns have a remarkable impact on the ozone yield by affecting the uniformity and turbulenee of gas flow.Meanwhile,distributing the O2 flow rate according to the intensity of the plasma reaction would also increase the generation efficiency of SDBD for ozone production.By improving the uniformity and introducing the lateral flow to the transversal flow,the highest ozone yield was obtained in flow pattern'F‘.In this case,the ozone yield increased by 28.4%to 131 g kWh^-1 from 102.8 g kWh^-1 in flow pattern‘A’. 展开更多
关键词 surface DIELECTRIC BARRIER DISCHARGE gas flow OZONE generation
Breakdown characteristics of CF3I/N2/CO2 mixture in power frequency and lightning impulse voltages
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作者 林启明 赵谡 +1 位作者 肖登明 周柏杰 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第1期36-43,共8页
Trifluoroiodomethane(CF3I) and its mixtures are believed to be prospective alternatives to sulfur hexafluoride(SF6), which has been included as a greenhouse gas. In this paper, the breakdown properties of a CF3I/N2/CO... Trifluoroiodomethane(CF3I) and its mixtures are believed to be prospective alternatives to sulfur hexafluoride(SF6), which has been included as a greenhouse gas. In this paper, the breakdown properties of a CF3I/N2/CO2 mixture with the volume fraction of CF3I fixed at 10% are investigated under power frequency and lightning impulse voltages. The experimental result shows that N2 possesses higher power frequency and negative lightning impulse breakdown voltages than CO2, but the power frequency and more negative lightning impulse breakdown voltages of the CF3I/N2/CO2 mixture do not increase with the content of N2. For the purpose of explaining this abnormal phenomenon, the ionization energies and excitation energies of CF3I,N2and CO2 are calculated. The computation results indicate that the ionization energy of CF3I is lower than the first excitation energy of N2, but higher than the lowest excitation energy of CO2,which means that CF3I molecules are easily ionized by metastable N2 molecules. The first excitation energy of N2 is too high, which hinders its application as the buffer gas of CF3I. 展开更多
关键词 GAS DISCHARGE CF3I GAS MIXTURES Penning EFFECT BUFFER GAS
A comparison of emissive and cold floating probe techniques for electric potential measurements in rf inductive discharge
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作者 Yaroslav MURZAEV Gen nadii LIZIAKIN +2 位作者 An drey GAVRIKOV Rinat TIMIRKHANOV Valentin SMIRNOV 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第4期94-98,共5页
A cold floating probe method was compared with the emissive floating probe method in terms of a low-pressure radio-frequency inductive discharge.The dependences of difference between the plasma potential and the float... A cold floating probe method was compared with the emissive floating probe method in terms of a low-pressure radio-frequency inductive discharge.The dependences of difference between the plasma potential and the floating potential on the electron temperature 1-8 eV,plasma density 109-1012 cm 3 and magnetic field 100-650 G were obtained.It was demonstrated that the difference between the potentials that obtained by these two methods can differ significantly from the expected value of 5.2 kTe/e for argon. 展开更多
关键词 emissive PROBE FLOATING PROBE rf INDUCTIVE DISCHARGE PLASMA potential measurement
渤海油田普通稠油冷采测试工艺 预览
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作者 高科超 高飞 +2 位作者 杨子 杨歧年 刘宝坤 《油气井测试》 2019年第1期38-45,共8页
针对渤海油田稠油井测试过程中存在的出砂、垂直管流黏阻大流动困难、PVT取样成功率低、计量误差大等难题,从射孔、防砂、控温、取样及计量工艺优化等方面细化研究,形成了由稳岩控砂射孔诱喷技术、井下测试管柱控温技术、稠油PVT取样技... 针对渤海油田稠油井测试过程中存在的出砂、垂直管流黏阻大流动困难、PVT取样成功率低、计量误差大等难题,从射孔、防砂、控温、取样及计量工艺优化等方面细化研究,形成了由稳岩控砂射孔诱喷技术、井下测试管柱控温技术、稠油PVT取样技术和稠油测试配套计量技术组成的普通稠油井冷采测试工艺。该工艺采用大孔径、深穿透、高密度射孔技术配合合适的诱喷压差提高油层渗流能力,联合井筒保温和加热技术降低原油在井筒中的流动阻力,优化取样器放置位置和取样时机,采用具有压力补偿功能的单相取样器保证取样准确性,配备可加热式的25m^3计量罐实现精确计量。渤海油田蓬莱31-X1井现场应用表明,取样压差仅为0.925MPa,取样合格;采用螺杆泵排液求产,80r/min时日产油52.84m^3,130r/min时日产油89.28m^3;四次开关井均取得了合格的压力数据资料。该工艺为类似稠油油田产能释放及有效动用提供了技术支撑。 展开更多
关键词 渤海油田 普通稠油 试采 射孔 控温 取样 计量 排液
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Three decades of changes in water environment of a large freshwater Lake and its relationship with socio-economic indicators
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作者 Cuicui Li Weiying Feng +5 位作者 Fanhao Song Zhongqi He Fengchang Wu Yuanrong Zhu John P.Giesy Yingchen Bai 《环境科学学报:英文版》 SCIE EI CAS CSCD 2019年第3期156-166,共11页
Tai Lake(Ch: Taihu) has attracted international attention forcyanobacteria blooms.However, the drivers of cultural eutrophication, especially long-term socio-economic indicators have been little researched. The result... Tai Lake(Ch: Taihu) has attracted international attention forcyanobacteria blooms.However, the drivers of cultural eutrophication, especially long-term socio-economic indicators have been little researched. The results of research demonstrate how socioeconomic development affected quality of water and how it has been improved by anthropogenic activities. This study described variability in indicators of water quality in Tai Lakeand investigated thedrivers. Significant relationships existed between concentrations of annual mean total nitrogen(TN), total phosphorous(TP), chemical oxygen demand(COD) and biological oxygen demand(BOD), and population, per capital gross domestic production(GDP) and sewage discharge(p < 0.05). However, mechanisms causing change varied among TN, TP, COD and BOD. Before 2000, the main contributors to increases in concentrations of TN were human population, GDP and volumes of domestic sewage discharges. After 2000, discharges of industrial sewage become the primary contributor. After 1998, the regressions of annual mean TN, TP and COD on per capital GDP, population and domestic sewage discharge were reversed compared to the former period. Since 1999, an apparent inverted U-shaped relationship between environmental pollution and economic development has developed, which indicated that actions taken by governments have markedly improved quality of water in Tai Lake. The statistical relationship between BOD and per capital GDP didn’t conform to the Kuznet curve. The Ushaped Kuznet curve may offer hope for the future that with significant environmental investments a high GDP can be reached and maintained without degradation of the environment, especially through appropriate management of industrial sewage discharge. 展开更多
关键词 EUTROPHIC LAKE Water environment INDICATORS Population GDP SEWAGE discharge Asia
Effect of glow discharge on hypersonic flat plate boundary layer 预览
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作者 Chi LI Yunchi ZHANG 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第2期249-260,共12页
Glow discharge is introduced as an artificial disturbance to investigate the evolution of first-and second-mode instabilities in a hypersonic flat plate boundary layer.Experiments are conducted in a Mach 6.5 quiet win... Glow discharge is introduced as an artificial disturbance to investigate the evolution of first-and second-mode instabilities in a hypersonic flat plate boundary layer.Experiments are conducted in a Mach 6.5 quiet wind tunnel using Rayleigh scattering visualization and particle image velocimetry(PIV).Detailed analysis of the experimental observations is provided.It is found that the artificially introduced 17 kHz disturbance,which belongs to the first-mode frequency band,can effectively enhance first-mode waves.Moreover,it can enhance second-mode waves even more intensely.Possible mechanisms to explain this phenomenon are discussed. 展开更多
关键词 GLOW DISCHARGE HYPERSONIC particle image velocimetry(PIV)
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Effects of secondary electron emission on plasma characteristics in dual-frequency atmospheric pressure helium discharge by fluid modeling
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作者 王一男 李帅星 +1 位作者 刘悦 王莉 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第2期346-351,共6页
A one-dimensional(1D) fluid simulation of dual frequency discharge in helium gas at atmospheric pressure is carried out to investigate the role of the secondary electron emission on the surfaces of the electrodes. In ... A one-dimensional(1D) fluid simulation of dual frequency discharge in helium gas at atmospheric pressure is carried out to investigate the role of the secondary electron emission on the surfaces of the electrodes. In the simulation, electrons,ions of He+ and He2+, metastable atoms of He*and metastable molecules of He*2 are included. It is found that the secondary electron emission coefficient significantly influences plasma density and electric field as well as electron heating mechanisms and ionization rate. The particle densities increase with increasing SEE coefficient from 0 to 0.3 as well as the sheath’s electric field and electron source. Moreover, the SEE coefficient also influences the electron heating mechanism and electron power dissipation in the plasma and both of them increase with increasing SEE coefficient within the range from 0 to 0.3 as a result of increasing of electron density. 展开更多
关键词 dual frequency SECONDARY electron emission ATMOSPHERIC pressure DISCHARGE
Operando FT-IR study on basicity improvement of Ni(Mg,AI)O hydrotalcitederived catalysts promoted by glow plasma discharge
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作者 R DEBEK D WIERZBICKI +3 位作者 M MOTAK M E GALVEZ P DA COSTA F AZZOLINA-JURY 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第4期123-136,共14页
CO2 adsorption on the surface of hydrotalcite-derived mixed oxide catalysts was investigated under low pressure glow discharge plasma in opercindo conditions via FT-IR spectroscopy.Nickel catalysts were promoted with ... CO2 adsorption on the surface of hydrotalcite-derived mixed oxide catalysts was investigated under low pressure glow discharge plasma in opercindo conditions via FT-IR spectroscopy.Nickel catalysts were promoted with various transition metal species(Ce,Fe,La,Zr)to influence their physico-chemical properties.Fe and Zr species were successfully incorporated into hydrotalcite brucite layers.After calcination formed a single phase with Ni(Mg,A1)O mixed oxide,while La and Ce species formed separate phases.This had a consequence in the distribution of surface basic sites as well as in the affinity to CO produced upon CO2 dissociation in plasma.Plasma treatment activated the surface of prepared materials and changed their properties via the generation of strong basic sites associated with low coordinated surface oxygen anions.Moreover,the CO2 adsorption capacity of prepared materials increased after plasma treatment. 展开更多
关键词 plasma GLOW DISCHARGE BASICITY HYDROTALCITE carbon dioxide
Transition control of Mach 6.5 hypersonic flat plate boundary layer 预览
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作者 Yunchi ZHANG ChiLI 《应用数学和力学:英文版》 SCIE EI CSCD 2019年第2期283-292,共10页
An artificial disturbance is introduced into the boundary layer over a flat plate to investigate the effect on the transition process in the Mach 6.5 wind tunnel at Peking University.A linear stability theory(LST)is u... An artificial disturbance is introduced into the boundary layer over a flat plate to investigate the effect on the transition process in the Mach 6.5 wind tunnel at Peking University.A linear stability theory(LST)is utilized to predict the evolution of the eigenmodes,and the frequency of the artificial disturbance is chosen according to the LST results.The artificial disturbance is generated by glowing discharge on the surface of the plate close to the leading edge.The Rayleigh-scattering visualization and particle image velocimetry(PIV)measurements are performed.By comparing the experimental results with artificial disturbances with those under the natural condition(without artificial disturbances),the present paper shows that the second-mode instability waves are significantly stimulated by the artificial disturbances,and the boundary layer transition is effectively triggered. 展开更多
关键词 HYPERSONIC BOUNDARY layer TRANSITION control glowing DISCHARGE
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风电场主变差动速断保护误动事件分析及处理 预览
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作者 王彦领 殷浩 《电力安全技术》 2019年第1期36-38,共3页
对一起风电场主变低压侧10kV母线穿墙套管放电引起的差动速断保护误动事件进行分析,找出主变跳闸的原因,指出事件暴露的问题,并提出对该种问题的整改措施,以供同类型风电场参考。
关键词 主变压器 差动速断 母线穿墙套管 放电
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Nitrogen and Phosphorus Dual-Doped Multilayer Graphene as Universal Anode for Full Carbon-Based Lithium and Potassium Ion Capacitors
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作者 Yuting Luan Rong Hu +6 位作者 Yongzheng Fang Kai Zhu Kui Cheng Jun Yan Ke Ye Guiling Wang Dianxue Cao 《纳微快报:英文版》 CAS CSCD 2019年第2期166-178,共13页
Lithium/potassium ion capacitors(LICs/PICs) have been proposed to bridge the performance gap between high-energy batteries and high-power capacitors.However,their development is hindered by the choice,electrochemical ... Lithium/potassium ion capacitors(LICs/PICs) have been proposed to bridge the performance gap between high-energy batteries and high-power capacitors.However,their development is hindered by the choice,electrochemical performance,and preparation technique of the battery-type anode materials.Herein,a nitrogen and phosphorus dual-doped multilayer graphene(NPG) material is designed and synthesized through an arc discharge process,using low-cost graphite and solid nitrogen and phosphorus sources.When employed as the anode material,NPG exhibits high capacity,remarkable rate capability,and stable cycling performance in both lithium and potassium ion batteries.This excellent electrochemical performance is ascribed to the synergistic effect of nitrogen and phosphorus doping,which enhances the electrochemical conductivity,provides a higher number of ion storage sites,and leads to increased interlayer spacing.Full carbon-based NPG‖LiPF6‖active carbon(AC) LICs and NPG‖KPF6‖AC PICs are assembled and show excellent electrochemical performance,with competitive energy and power densities.This work provides a route for the large-scale production of dual-doped graphene as a universal anode material for high-performance alkali ion batteries and capacitors. 展开更多
关键词 Arc discharge GRAPHENE HETEROATOM doping Lithium/potassium ION battery Lithium/potassium ION capacitor
Artificial neural network simulation for prediction of suspended sediment concentration in the River Ramganga, Ganges Basin, India 预览
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作者 Mohd Yawar Ali Khan Fuqiang Tian +1 位作者 Faisal Hasan Govind Joseph Chakrapani 《国际泥沙研究:英文版》 SCIE 2019年第2期95-107,共13页
The relation between the water discharge (Q) and suspended sediment concentration (SSC) of the River Ramganga at Bareilly, Uttar Pradesh, in the Himalayas, has been modeled using Artificial Neural Networks (ANNs). The... The relation between the water discharge (Q) and suspended sediment concentration (SSC) of the River Ramganga at Bareilly, Uttar Pradesh, in the Himalayas, has been modeled using Artificial Neural Networks (ANNs). The current study validates the practical capability and usefulness of this tool for simulating complex nonlinear, real world, river system processes in the Himalayan scenario. The modeling approach is based on the time series data collected from January to December (2008-2010) for Q and SSC. Three ANNs (T1-T3) with different network configurations have been developed and trained using the Levenberg Marquardt Back Propagation Algorithm in the Matlab routines. Networks were optimized using the enumeration technique, and, finally, the best network is used to predict the SSC values for the year 2011. The values thus obtained through the ANN model are compared with the observed values of SSC. The coefficient of determination (R2), for the optimal network was found to be 0.99. The study not only provides insight into ANN modeling in the Himalayan river scenario, but it also focuses on the importance of understanding a river basin and the factors that affect the SSC, before attempting to model it. Despite the temporal variations in the study area, it is possible to model and successfully predict the SSC values with very simplistic ANN models. 展开更多
关键词 ANN Water DISCHARGE Suspended SEDIMENT concentration PREDICTION Ramganga RIVER HIMALAYAS
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Prediction of daily sediment discharge using a back propagation neural network training algorithm: A case study of the Narmada River, India 预览
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作者 Nibedita Bisoyi Harish Gupta +1 位作者 Narayan Prasad Padhy Govind Joseph Chakrapani 《国际泥沙研究:英文版》 SCIE 2019年第2期125-135,共11页
Most of the studies on Artificial Neural Network (ANN) models remain restricted to smaller rivers and catchments. In this paper, an attempt has been made to correlate variability of sediment loads with rainfall and ru... Most of the studies on Artificial Neural Network (ANN) models remain restricted to smaller rivers and catchments. In this paper, an attempt has been made to correlate variability of sediment loads with rainfall and runoff through the application of the Back Propagation Neural Network (BPNN) algorithm for a large tropical river. The algorithm and simulation are done through MATLAB environment. The methodology comprised of a collection of data on rainfall, water discharge, and sediment discharge for the Narmada River at various locations (along with time variables) and application to develop a threelayer BPNN model for the prediction of sediment discharges. For training and validation purposes a set of 549 data points for the monsoon (16 June-15 November) period of three consecutive years (1996–1998) was used. For testing purposes, the BPNN model was further trained using a set of 732 data points of monsoon season of four years (2006–07 to 2009–10) at nine stations. The model was tested by predicting daily sediment load for the monsoon season of the year 2010–11. To evaluate the performance of the BPNN model, errors were calculated by comparing the actual and predicted loads. The validation and testing results obtained at all these locations are tabulated and discussed. Results obtained from the model application are robust and encouraging not only for the sub-basins but also for the entire basin. These results suggest that the proposed model is capable of predicting the daily sediment load even at downstream locations, which show nonlinearity in the transportation process. Overall, the proposed model with further training might be useful in the prediction of sediment discharges for large river basins. 展开更多
关键词 Artificial neural network BACK PROPAGATION Sediment DISCHARGE PREDICTION Error Narmada RIVER
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Lesions of mediodorsal thalamic nucleus reverse abnormal firing of the medial prefrontal cortex neurons in parkinsonian rats 预览
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作者 Ling-Ling Fan Bo Deng +3 位作者 Jun-Bao Yan Zhi-Hong Hu Ai-Hong Ren Dong-Wei Yang 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第9期1635-1642,共8页
The dysfunction of the medial prefrontal cortex is associated with affective disorders and non-motor features in Parkinson’s disease.However,the exact role of the mediodorsal thalamic nucleus in the function of the p... The dysfunction of the medial prefrontal cortex is associated with affective disorders and non-motor features in Parkinson’s disease.However,the exact role of the mediodorsal thalamic nucleus in the function of the prefrontal cortex remains unclear.To study the possible effects of the mediodorsal thalamic nucleus on the neurological function of the medial prefrontal cortex,a model of Parkinson’s disease was established by injecting 8μg 6-hydroxydopamine into the substantia nigra compacta of rats.After 1 or 3 weeks,0.3μg ibotenic acid was injected into the mediodorsal thalamic nucleus of the midbrain.At 3 or 5 weeks after the initial injury,neuronal discharge in medial prefrontal cortex of rat brain was determined electrophysiologically.The numbers of dopamine-positive neurons and tyrosine hydroxylase immunoreactivity in substantia nigra compacta and ventral tegmental area were detected by immunohistochemical staining.Results demonstrated that after injury,the immunoreactivity of dopamine neurons and tyrosine hydroxylase decreased in the substantia nigra compacta and ventral tegmental areas of rats.Compared with normal medial prefrontal cortical neurons,at 3 and 5 weeks after substantia nigra compacta injury,the discharge frequency of pyramidal neurons increased and the discharge pattern of these neurons tended to be a burst-discharge,with an increased discharge interval.The discharge frequency of interneurons decreased and the discharge pattern also tended to be a burst-discharge,but the discharge interval was only higher at 3 weeks.At 3 weeks after the combined lesions,the discharge frequency,discharge pattern and discharge interval were restored to a normal level in pyramidal neurons and interneurons in medial prefrontal cortex.These findings have confirmed that mediodorsal thalamic nucleus is involved in regulating neuronal activities of the medial prefrontal cortex.The changes in the function of the mediodorsal thalamic nucleus may be associated with the abnormal discharge activity of the medial prefron 展开更多
关键词 nerve REGENERATION Parkinson's disease mediodorsal THALAMIC nucleus medial PREFRONTAL cortex PYRAMIDAL NEURONS INTERNEURONS discharge neural REGENERATION
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家庭康复护理对脑卒中患者的影响研究 预览
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作者 高艳丽 《中国继续医学教育》 2019年第8期183-185,共3页
目的探讨家庭康复护理模式在脑卒中恢复期患者出院后的应用效果。方法选择2017年1-11月的出院后脑卒中恢复期患者80例作为研究对象。将其随机分为两组。观察组(40例)采用家庭康复护理模式护理,对照组(40例)采用一般家庭照顾模式护理。... 目的探讨家庭康复护理模式在脑卒中恢复期患者出院后的应用效果。方法选择2017年1-11月的出院后脑卒中恢复期患者80例作为研究对象。将其随机分为两组。观察组(40例)采用家庭康复护理模式护理,对照组(40例)采用一般家庭照顾模式护理。观察比较两组患者干预2周、3个月及6个月时的日常生活活动能力评分(Barthel指数)、美国国立卫生研究院卒中量表(NIHSS)评分。结果经出院后2周、3个月和6个月护理后,观察组患者Barthel指数评分均高于对照组,组间各数据比较,差异均具有统计学意义(P<0.05)。观察组患者NIHSS评分均低于对照组,组间各数据比较,差异均具有统计学意义(P<0.05)。结论家庭康复护理模式能有效改善脑卒中恢复期患者出院后日常生活活动能力以及促进神经功能恢复。 展开更多
关键词 脑卒中恢复期 出院 家庭 康复护理 护士 日常生活活动能力
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