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Current Model Analysis of South China Sea Based on Empirical Orthogonal Function(EOF)Decomposition and Prototype Monitoring Data 预览
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作者 WU Wenhua LIU Ming +1 位作者 YU Siyuan WANG Yanlin 《中国海洋大学学报:英文版》 SCIE CAS CSCD 2019年第2期305-316,共12页
Environmental load is the primary factor in the design of offshore engineering structures and ocean current is the principal environmental load that causes underwater structural failure.In computational analysis,the c... Environmental load is the primary factor in the design of offshore engineering structures and ocean current is the principal environmental load that causes underwater structural failure.In computational analysis,the calculation of current load is mainly based on the current profile.The current profile model,which is based on a structural failure criterion,is conducive to decreasing the uncertainty of the current load.In this study,we used prototype monitoring data and the empirical orthogonal function(EOF)method to investigate the current profile in the South China Sea and its correlation with the design of underwater structural strength and the dynamic design of fatigue.The underwater structural strength design takes into account the size of the structure and the service water depth.We propose profiles for the overall and local designs using the inverse first-order reliability method(IFORM).We extracted the characteristic profile current(CPC)of the monitored sea area to solve dynamic design problems such as vortex-induced vibration(VIV).We used random sampling to verify the feasibility of using the EOF method to calculate the CPC from the current data and identified the main problems associated with using the CPC,which deserve close attention in VIV design.Our research conclusions provide direct references for determining current load in this sea area.This analysis method can also be used in the analysis of other sea areas or field variables. 展开更多
关键词 CURRENT PROFILE model failure criteria PROTOTYPE monitoring inverse FIRST-ORDER reliability method(IFORM) Characteristic PROFILE current(CPC)
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Numerical modeling of lock-exchange gravity/turbidity currents by a high-order upwinding combined compact difference scheme 预览
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作者 Liang Zhao Ching-Hao Yu Zhiguo He 《国际泥沙研究:英文版》 SCIE 2019年第3期240-250,共11页
This study presents two-dimensional direct numerical simulations for sediment-laden current with higher density propagating forward through a lighter ambient water.The incompressible NavierStokes equations including t... This study presents two-dimensional direct numerical simulations for sediment-laden current with higher density propagating forward through a lighter ambient water.The incompressible NavierStokes equations including the buoyancy force for the density difference between the light and heavy fluids are solved by a finite difference scheme based on a structured mesh.The concentration transport equations are used to explore such rich transport phenomena as gravity and turbidity currents.Within the framework of an Upwinding Combined Compact finite Difference(UCCD)scheme,rigorous determination of weighting coefficients underlies the modified equation analysis and the minimization of the numerical modified wavenumber.This sixth-order UCCD scheme is implemented in a four-point grid stencil to approximate advection and diffusion terms in the concentration transport equations and the first-order derivative terms in the Navier-Stokes equations,which can greatly enhance convective stability and increase dispersive accuracy at the same time.The initial discontinuous concentration field is smoothed by solving a newly proposed Heaviside function to prevent numerical instabilities and unreasonable concentration values.A two-step projection method is then applied to obtain the velocity field.The numerical algorithm shows a satisfying ability to capture the generation,development,and dissipation of the Kelvin-Helmholz instabilities and turbulent billows at the interface between the current and the ambient fluid.The simulation results also are compared with the data in published literatures and good agreements are found to prove that the present numerical model can well reproduce the propagation,particle deposition,and mixing processes of lock-exchange gravity and turbidity currents. 展开更多
关键词 GRAVITY CURRENT TURBIDITY CURRENT Depth-resolving mathematical model INCOMPRESSIBLE Navier-Stokes equations Upwinding COMBINED Compact Difference(UCCD) scheme
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Improving the data retention of phase change memory by using a doping element in selected Ge2Sb2Te5 预览
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作者 Yaoyao Lu Daolin Cai +5 位作者 Yifeng Chen Shuai Yan Lei Wu Yuanguang Liu Yang Li Zhitang Song 《半导体学报:英文版》 EI CAS CSCD 2019年第4期29-34,共6页
The crystallization characteristics of a ubiquitous T-shaped phase change memory (PCM) cell, under SET current pulse and very small disturb current pulse, have been investigated by finite element modelling. As analyze... The crystallization characteristics of a ubiquitous T-shaped phase change memory (PCM) cell, under SET current pulse and very small disturb current pulse, have been investigated by finite element modelling. As analyzed in this paper, the crystallization region under SET current pulse presents first on the corner of the bottom electron contact (BEC) and then promptly forms a filament shunting down the amorphous phase to achieve the low-resistance state, whereas the tiny disturb current pulse accelerates crystallization at the axis of symmetry in the phase change material. According to the different crystallization paths, a new structure of phase change material layer is proposed to improve the data retention for PCM without impeding SET operation. This structure only requires one or two additional process steps to dope nitrogen element in the center region of phase change material layer to increase the crystallization temperature in this confined region. The electrical-thermal characteristics of PCM cells with incremental doped radius have been analyzed and the best performance is presented when the doped radius is equal to the radius of the BEC. 展开更多
关键词 phase change memory CRYSTALLIZATION process SET CURRENT PULSE small disturb CURRENT PULSE finite ELEMENT simulation
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On Grauert–Riemenschneider Type Criteria
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作者 Zhi Wei WANG 《数学学报:英文版》 SCIE CSCD 2019年第5期609-618,共10页
Let (X,ω) be a compact Hermitian manifold of complex dimension n. In this article, we first survey recent progress towards Grauert-Riemenschneider type criteria. Secondly, we give a simplified proof of Boucksom's... Let (X,ω) be a compact Hermitian manifold of complex dimension n. In this article, we first survey recent progress towards Grauert-Riemenschneider type criteria. Secondly, we give a simplified proof of Boucksom's conjecture given by the author under the assumption that the Hermitian metric ω satisfies ■■ω^l=for all l, i.e., if T is a closed positive current on X such that ∫X Tcn/^n>0, then the class {T} is big and X is K?hler. Finally, as an easy observation, we point out that Nguyen's result can be generalized as follows:if ■■ω=0, and T is a closed positive current with analytic singularities, such that ∫X Tcn/^n>0, then the class {T} is big and X is Kahler. 展开更多
关键词 CLOSED POSITIVE CURRENT Demailly-Paun's CONJECTURE Boucksom's CONJECTURE KAHLER CURRENT Fujiki class
Electrical Brain Stimulation to Treat Neurological Disorder 预览
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作者 Bahman Zohuri David R.Modisette 《健康科学:英文版》 2019年第2期123-128,共6页
Neurological disorders with symptoms such as chronic pain,depression,and insomnia are widespread.Very weak electric fields applied through the skull can enhance or diminish neural activity and modulate brain waves in ... Neurological disorders with symptoms such as chronic pain,depression,and insomnia are widespread.Very weak electric fields applied through the skull can enhance or diminish neural activity and modulate brain waves in order to treat many of these common medical problems.This approach is to be contrasted with well-established pharmacological methods or more recent invasive electrical Deep Brain Stimulation(DBS)techniques that require surgery to insert electrodes deep into the brain.We claim that Non-Invasive Brain Stimulation(NIBS)will provide new treatment methods with much greater simplicity,lower cost,improved safety and in some cases,possibly greater effectiveness.This emerging use of NIBS is a branch of a new multidisciplinary field that we coined Neuro-systems Engineering[1].This field involves neuroscientists,psychologists,and electrical engineers.This emerging field relies on existing standards for the safe implementation of these novel treatment modalities[2].Methods of stimulating the brain are based on emerging electro-technologies such as transcranial Direct Current/Alternating Current(DC/AC)electric fields and pulsed magnetic fields.Application of functional and time-dependent brain imaging methods can be used to locate relevant brain regions and determine the most appropriate stimulation method.Application of tailored and individualized control can be combined with other therapy methods to effectively treat neurological disorders while minimizing or even eliminating the use of pharmaceuticals.In this paper,we are presenting our embodiment for a closed loop,feedback controlled,non-invasive application of electrical stimulation of the brain to enhance individual/group performance or to treat neurological disorders. 展开更多
关键词 REPETITIVE TRANSCRANIAL Magnetic Stimulation(rTMS) REPETITIVE TRANSCRANIAL Electric Stimulation(rTES) Deep Brain Stimulation(DBS) Electroencephalogram(EEG) Magnetoencephalography(MEG) TRANSCRANIAL Direct CURRENT Stimulation(tDCS) TRANSCRANIAL Alternating CURRENT Stimulation(tACS)
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Current diffusion and efficiency droop in vertical light emitting diodes
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作者 万荣桥 李滔 +6 位作者 刘志强 伊晓燕 王军喜 李军辉 朱文辉 李晋闽 汪炼成 《中国物理B:英文版》 SCIE EI CAS CSCD 2019年第1期561-569,共9页
Current diffusion is an old issue, nevertheless, the relationship between the current diffusion and the efficiency of light emitting diodes(LEDs) needs to be further quantitatively clarified. By incorporating current ... Current diffusion is an old issue, nevertheless, the relationship between the current diffusion and the efficiency of light emitting diodes(LEDs) needs to be further quantitatively clarified. By incorporating current crowding effect(CCE) into the conventional ABC model, we have theoretically and directly correlated the current diffusion and the internal quantum efficiency(IQE), light extraction efficiency(LEE), and external quantum efficiency(EQE) droop of the lateral LEDs.However, questions still exist for the vertical LEDs(V-LEDs). Here firstly the current diffusion length L_s(I) and L_s(II) have been clarified. Based on this, the influence of CCE on the EQE, IQE, and LEE of V-LEDs were investigated. Specifically to our V-LEDs with moderate series resistivity, L_s(III) was developed by combining L_s(I) and L_s(II), and the CCE effect on the performance of V-LEDs was investigated. The wall-plug efficiency(WPE) of V-LEDs ware investigated finally. Our works provide a deep understanding of the current diffusion status and the correlated efficiency droop in V-LEDs, thus would benefit the V-LEDs’ chip design and further efficiency improvement. 展开更多
关键词 efficiency droop VERTICAL light EMITTING diodes CURRENT CROWDING effect CURRENT BLOCKING layer
Direct Microwave Synthesis of 11-Type Fe(Te,Se)Polycrystalline Superconductors with Enhanced Critical Current Density
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作者 潘伯津 赵康 +4 位作者 刘通 阮彬彬 张帅 陈根富 任治安 《中国物理快报:英文版》 SCIE CAS CSCD 2019年第1期56-59,共4页
We report a direct microwave synthesis method for the preparation of 11-type high quality Fe(Te,Se)polycrys- talline superconductors.The bulk samples are rapidly synthesized under the microwave irradiation during seve... We report a direct microwave synthesis method for the preparation of 11-type high quality Fe(Te,Se)polycrys- talline superconductors.The bulk samples are rapidly synthesized under the microwave irradiation during several minutes,with a subsequent annealing process at 400℃.The samples exhibit a nearly single phase of the tetragonal PbO-type crystal structure with minor impurities.Morphology characterization shows high density,tight grain connectivity and large grain sizes around 100μm with small cavities inside the sample.Resistivity and magnetization measurements both show similar superconducting transitions above 14 K.The magnetic hystere- sis measurements display broad and symmetric loops without magnetic background,and a high critical current density Jc about 1.2 ×10^4 A/cm^2 at 2K and 7T is estimated by the Bean model.Compared with the solid- state reaction synthesized samples,these superconducting bulks from microwave-assisted synthesis are possibly free of the interstitial Fe due to smaller c-axis,higher Tc in magnetic transitions,better M-H loops without magnetic background and greatly enhanced Jc,and are promising as raw materials for the non-toxic Fe-based superconducting wires for large currents and high field applications. 展开更多
关键词 MICROWAVE Synthesis POLYCRYSTALLINE SUPERCONDUCTORS ENHANCED CRITICAL Current Density
Experimental investigations of enhanced glow based on a pulsed hollow-cathode discharge
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作者 梁春霞 王宁 +2 位作者 段正超 何锋 欧阳吉庭 《等离子体科学与技术:英文版》 SCIE EI CAS CSCD 2019年第2期47-51,共5页
In this work, the pulsed hollow cathode discharges at low pressure argon with an axial magnetic field were studied. The results indicate that the pulsed discharge is operated in an enhanced glow(EG) mode. Under the sa... In this work, the pulsed hollow cathode discharges at low pressure argon with an axial magnetic field were studied. The results indicate that the pulsed discharge is operated in an enhanced glow(EG) mode. Under the same conditions, the discharge current of the pulsed discharge is two or three orders higher than that of the direct current discharge. The spatial and temporal evolution of the light emission shows that, the current fluctuation at the rising edge of the pulse plays an important role for the EG discharge of pulsed hollow cathode, which forms a high-density, highcurrent and long-distance plasma column outside the cavity. 展开更多
关键词 HOLLOW cathode discharge ENHANCED GLOW current FLUCTUATION ABNORMAL GLOW
Current therapies and novel approaches for biliary diseases 预览
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作者 Indu G Rajapaksha Peter W Angus Chandana B Herath 《世界胃肠病理生理学杂志:英文版(电子版)》 2019年第1期1-10,共10页
Chronic liver diseases that inevitably lead to hepatic fibrosis, cirrhosis and/or hepatocellular carcinoma have become a major cause of illness and death worldwide. Among them, cholangiopathies or cholestatic liver di... Chronic liver diseases that inevitably lead to hepatic fibrosis, cirrhosis and/or hepatocellular carcinoma have become a major cause of illness and death worldwide. Among them, cholangiopathies or cholestatic liver diseases comprise a large group of conditions in which injury is primarily focused on the biliary system. These include congenital diseases (such as biliary atresia and cystic fibrosis), acquired diseases (such as primary sclerosing cholangitis and primary biliary cirrhosis), and those that arise from secondary damage to the biliary tree from obstruction, cholangitis or ischaemia. These conditions are associated with a specific pattern of chronic liver injury centered on damaged bile ducts that drive the development of peribiliary fibrosis and, ultimately, biliary cirrhosis and liver failure. For most, there is no established medical therapy and, hence, these diseases remain one of the most important indications for liver transplantation. As a result, there is a major need to develop new therapies that can prevent the development of chronic biliary injury and fibrosis. This mini-review briefly discusses the pathophysiology of liver fibrosis and its progression to cirrhosis. We make a special emphasis on biliary fibrosis and current therapeutic options, such as angiotensin converting enzyme-2 (known as ACE2) over-expression in the diseased liver as a novel potential therapy to treat this condition. 展开更多
关键词 Chronic liver disease BILIARY FIBROSIS CURRENT THERAPIES for BILIARY FIBROSIS ANGIOTENSIN CONVERTING enzyme-2 Gene therapy
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Interplanetary shock-associated aurora 预览
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作者 LIU Jianjun HU Hongqiao +1 位作者 HAN Desheng YANG Huigen 《极地科学进展:英文版》 CSCD 2019年第1期11-23,共13页
Interplanetary shocks or solar wind pressure pulses have prompted impacts on Earth’s magnetospheric and ionospheric environment, especially in causing dynamic changes to the bright aurora in the polar ionosphere. The... Interplanetary shocks or solar wind pressure pulses have prompted impacts on Earth’s magnetospheric and ionospheric environment, especially in causing dynamic changes to the bright aurora in the polar ionosphere. The auroral phenomenon associated with shock impingements, referred to as shock aurora, exhibits distinct signatures differing from other geophysical features on the dayside polar ionosphere. Shock aurora provides a direct manifestation of the solar wind–magnetosphere–ionosphere interaction. Imagers onboard satellites can obtain the associated large-scale auroral characteristics during shock impingement on the magnetopause. Therefore, auroral data from satellites are very useful for surveying the comprehensive features of shock aurora and their general evolution. Nonetheless, the ground-based high temporal-spatial resolution all-sky imagers installed at scientific stations play an essential role in revealing medium-and small-scale characteristics of shock aurora. Here, we focus on shock aurora imaging signatures measured by imagers onboard satellites and ground-based all-sky imagers. 展开更多
关键词 INTERPLANETARY shock SUDDEN IMPULSE shock AURORA wave-particle interaction field-aligned current
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单液流锌鎳电池的能量损失及工作效率 预览
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作者 金海浪 宋春宁 +1 位作者 郭振邦 严兴龙 《电池》 CAS CSCD 北大核心 2019年第1期17-20,共4页
依据库仑效率、能量效率及系统效率等3个指标,探究充放电电流、充电容量对单液流锌標电池能量损失和工作效率的影响。充放电电流从80A变化到180A时,库仑效率和系统效率变化幅度较小,能量效率随着充电电流的增加而降低。充电容量从200Ah... 依据库仑效率、能量效率及系统效率等3个指标,探究充放电电流、充电容量对单液流锌標电池能量损失和工作效率的影响。充放电电流从80A变化到180A时,库仑效率和系统效率变化幅度较小,能量效率随着充电电流的增加而降低。充电容量从200Ah变化到300Ah时,库仑效率、能量效率以及系统效率都会随充电容量的增加而减少。 展开更多
关键词 单液流锌铢电池 电流 容量 能量损失 工作效率
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An innovative method for the microstructural modification of TiAl alloy solidified via direct electric current application
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作者 Zhanxing Chen Hongsheng Ding +3 位作者 Ruirun Chen Shiqiu Liu Jingjie Guo Hengzhi Fu 《材料科学技术学报:英文版》 SCIE EI CAS CSCD 2019年第1期23-28,共6页
Ti-48Al-2Cr-2Nb alloy solidified with the application of direct electric current has a refined and homogeneous microstructure without segregation. We observed an initial decrease followed by a subsequent increase in g... Ti-48Al-2Cr-2Nb alloy solidified with the application of direct electric current has a refined and homogeneous microstructure without segregation. We observed an initial decrease followed by a subsequent increase in grain size and lamellar spacing, with the increase in current density. Similar trend can also be obtained by varying the amount of α2-phase(Ti3Al). Using a directional solidification processing method,the columnar crystal microstructure transforms into an equiaxed crystal microstructure at a current density of 32–64 m A/mm2. High dislocation density is also introduced with a minimum cross-sectional grain size of 460 μm at a current density of 64 mA/mm2. The application of electric current alters the free energy of the critical nucleus and temperature via joule heating, causing a transformation from a columnar grain microstructure into an equiaxed grain microstructure. The increase in current density leads to a rise of the nucleation rate, and a resulting undercooling combined with temperature gradient contribute to growth of the primary phase, which finally results in grain coarsening at a critical current density of 96 mA/mm2.The climb and cross-slip of dislocation and the migration of grain boundary ultimately create variable lamellae spacing of TiAl alloy. 展开更多
关键词 TIAL SOLIDIFICATION DIRECT electric current Microstructure
Mechanisms by which fibroblast growth factor 20 improves motor performance in a mouse model of Parkinson's disease 预览
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作者 Ai-Qin Wang Li-Na Kong +3 位作者 Ming-Zhu Meng Xiu-He Zhao Si Chen Xiao-Tang Wang 《中国神经再生研究:英文版》 SCIE CAS CSCD 2019年第8期1438-1444,共7页
Genome-wide studies have reported that Parkinson's disease is associated with abnormal expression of various growth factors. In this study, male C57BL/6 mice aged 10 weeks were used to establish Parkinson's di... Genome-wide studies have reported that Parkinson's disease is associated with abnormal expression of various growth factors. In this study, male C57BL/6 mice aged 10 weeks were used to establish Parkinson's disease models using an intraperitoneal injection of 60 mg/kg 1-methyl- 4-phenyl-1,2,3,6-tetrahydropyridine. 28 days later, 10 or 100 ng fibroblast growth factor 20 was injected intracerebroventricularly. The electrophysiological changes in the mouse hippocampus were recorded using a full-cell patch clamp. Expression of Kv4.2 in the substantia nigra was analyzed using a western blot assay. Serum malondialdehyde levels were analyzed by enzyme-linked immunosorbent assay. The motor coordination of mice was evaluated using the rotarod test. The results showed that fibroblast growth factor 20 decreased A-type potassium current in neurons of the substantia nigra, increased long-term potentiation amplitude in the hippocampus, and downregulated Kv4.2 expression. A high dose of fibroblast growth factor 20 reduced serum malondialdehyde levels and enhanced the motor coordination of mice. These findings confirm that fibroblast growth factor 20 has a therapeutic effect on the toxicity induced by l-methyl-4-phenyl-l,2,3s6-tetrahydropyridine, and its mechanism of action is associated with the inhibition of A-type K^+ currents and Kv4.2 expression. All animal procedures were approved by the Animal Care and Use Committee of Qilu Hospital of Shandong University, China in 2017 (approval No. KYLL-2017-0012). 展开更多
关键词 nerve REGENERATION Parkinson's disease l-methyl-4-phenyl-1 2 3 6-tetrahydropyridine fibroblast growth factor 20 A-TYPE potassium current long-term POTENTIATION KV4.2 oxidative stress MALONDIALDEHYDE motor performance neural REGENERATION
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气体放电管与半导体放电管配合使用方法的分析
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作者 徐黄飞 张其林 +3 位作者 蔡露进 薛奇 朱若虚 刘超 《电瓷避雷器》 CAS 北大核心 2019年第1期22-30,共9页
针对防雷中半导体放电管(thyristor surge suppressors,TSS)和气体放电管(gas dischargetube,GDT)匹配的性能问题,设计了TSS与GDT配合工作的测试电路。使用(1. 2/50 s、8/20 s)组合波发生器模拟雷电过电压对该测试电路进行冲击试验。试... 针对防雷中半导体放电管(thyristor surge suppressors,TSS)和气体放电管(gas dischargetube,GDT)匹配的性能问题,设计了TSS与GDT配合工作的测试电路。使用(1. 2/50 s、8/20 s)组合波发生器模拟雷电过电压对该测试电路进行冲击试验。试验采取控制变量法,退耦电阻阻值选取2Ω、5Ω、10Ω,TSS工作电压选取6 V、25 V、58 V,GDT直流击穿电压选取90 V、230 V。得出:冲击电压小于GDT击穿电压时,测试电路工作在盲区内,仅有TSS动作;冲击电压超过GDT击穿电压时,TSS与GDT先后动作,GDT泄放的能量要远大于TSS;冲击电压增大超过1 kV时,GDT的动作时延将短于TSS,几乎所有的能量都由GDT泄放;GDT导通后,随着冲击电压的增加,GDT的残压和通流逐渐增大,而TSS的残压和通流逐渐减低并保持在一个较低的状态(残压在5 V左右,通流在7 A左右)。对TSS和GDT的应用有一定的参考意义。 展开更多
关键词 半导体放电管 气体放电管 盲区 通流 残压
电容式加速度传感器机电耦合分析 预览
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作者 牟维兵 《电子设计工程》 2019年第5期36-39,43共5页
为了研究电容式加速度传感器在受加速度外力作用过程中其端口电流的变化情况,建立了一个电容式传感器模型。在对电容模型进行有限元固体力学分析的基础上,将有限元模型代入电路中,通过机械、电路耦合仿真的方法模拟电容传感器端口的电... 为了研究电容式加速度传感器在受加速度外力作用过程中其端口电流的变化情况,建立了一个电容式传感器模型。在对电容模型进行有限元固体力学分析的基础上,将有限元模型代入电路中,通过机械、电路耦合仿真的方法模拟电容传感器端口的电流变化。模拟结果清楚显示了加速度作用对电容端口电流的影响,传感器所受加速度作用大小与其电流并非简单的线性关系,还与加速度方向紧密相关。只有机电耦合的分析方法才能揭示传感器电流在加速度加载时电流的变化过程。 展开更多
关键词 电容式传感器 加速度荷载 固体力学 机电耦合模拟 电流
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Observed characteristics of tidal currents and mean flow in the northern Yellow Sea 预览
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作者 BI Congcong BAO Xianwen +4 位作者 DING Yang ZHANG Cong WANG Yu SHEN Biao WAN Kai 《海洋湖沼学报(英文)》 SCIE CAS CSCD 2019年第2期461-473,共13页
Several bottom-mounted Acoustic Doppler Current Profiler (ADCP) moorings were deployed in the northern Yellow Sea (NYS) during the four seasons of 2006–2007 and also the summertime of 2009. A synthesis analysis on th... Several bottom-mounted Acoustic Doppler Current Profiler (ADCP) moorings were deployed in the northern Yellow Sea (NYS) during the four seasons of 2006–2007 and also the summertime of 2009. A synthesis analysis on the time-continuous records was performed to examine the characteristics and variations of tidal currents and mean flow over the observation period at these stations. Tidal currents accounted for ~75% of the total kinetic energy, with the absolute dominance of M2 constituent. Visible vertical variations of tidal flow were found on all sites, featured by the decrease of amplitude, increase of rotation rate as well as a decreasing trend of the phase for M2 component with depth. A notable exception was in the central NYS, where the maximum tidal currents occurred in the upper or middle layers (~20–40 m) instead of near the surface (<10 m). The observed mean flow was relatively weak, smaller than 15 cm/s. Velocity on the northern end of Yellow Sea Trough (YST) was characterized by low magnitude and an obvious layered structure vertically. In the Bohai Strait (BS) and the northern slope area, the currents weakened and the flow direction presented a major trend to deflect counterclockwise with depth in most observations. Summertime cyclonic circulation around the Yellow Sea Cold Water Mass (YSCWM), its intensification on the frontal zone and the Yellow Sea Warm Current (YSWC) for the winter season were all evident by our direct current measurements. However, the details of water exchange through the BS appeared partly diff erent from the traditionally-accepted pattern. The vertical diff erences of tidal and mean flow were larger in summer than that in winter, implying the influence of thermal structure to the local currents. Aff ected by the water stratification, mean flow usually reached its maximum near the thermocline in spring and summer, while showing a nearly uniform vertical distribution during winter. 展开更多
关键词 NORTHERN YELLOW Sea moored current measurements TIDAL CURRENTS mean flow thermal structure
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Second generation fully differential current conveyor based analog circuits 预览
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作者 A. Tonk N. Afzal 《半导体学报:英文版》 EI CAS CSCD 2019年第4期23-28,共6页
In this paper, we present a new voltage-mode biquad filter that uses a six-terminal CMOS fully differential current conveyor (FDCCII). The FDCCII with only 23 transistors in its structure and operating at ± 1.5 V... In this paper, we present a new voltage-mode biquad filter that uses a six-terminal CMOS fully differential current conveyor (FDCCII). The FDCCII with only 23 transistors in its structure and operating at ± 1.5 V, is based on a class AB fully differential buffer. The proposed filter has the facility to tune gain, o)0 and Q. A circuit division circuit (CDC) is employed to digitally control the FDCCII block. This digitally con trolled FDCCII is used to realize a new reconfigurable fully-differe ntial in tegrator and differentiator. We performed SPICE simulati ons to determi ne the performance of all circuits using CMOS 0.25 pm tech no logy. 展开更多
关键词 CURRENT conveyors fully DIFFERENTIAL digitally CONTROLLED INTEGRATOR DIFFERENTIATOR
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Chronic Intermittent Hypobaric Hypoxia Ameliorates Renal Vascular Hypertension Through Up-regulating NOS in Nucleus Tractus Solitarii
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作者 Na Li Yue Guan +4 位作者 Yan-Ming Tian Hui-Jie Ma Xiangjian Zhang Yi Zhang Sheng Wangb 《神经科学通报:英文版》 SCIE CAS CSCD 2019年第1期79-90,共12页
Chronic intermittent hypobaric hypoxia(CIHH)is known to have an anti-hypertensive effect, which might be related to modulation of the baroreflex in rats with renal vascular hypertension(RVH). In this study, RVH was in... Chronic intermittent hypobaric hypoxia(CIHH)is known to have an anti-hypertensive effect, which might be related to modulation of the baroreflex in rats with renal vascular hypertension(RVH). In this study, RVH was induced by the 2-kidney-1-clip method(2 K1 C) in adult male Sprague-Dawley rats. The rats were then treated with hypobaric hypoxia simulating 5000 m altitude for 6 h/day for 28 days. The arterial blood pressure(ABP), heart rate(HR), and renal sympathetic nerve activity(RSNA) were measured before and after microinjection of L-arginine into the nucleus tractus solitarii(NTS) in anesthetized rats.Evoked excitatory postsynaptic currents(eEPSCs) and spontaneous EPSCs(sEPSCs) were recorded in anterogradely-labeled NTS neurons receiving baroreceptor afferents. We measured the protein expression of neuronal nitric oxide synthase(nNOS) and endothelial NOS(eNOS) in the NTS. The results showed that the ABP in RVH rats was significantly lower after CIHH treatment. The inhibition of ABP, HR, and RSNA induced by L-arginine was less in RVH rats than in sham rats, and greater in the CIHHtreated RVH rats than the untreated RVH rats. The eEPSC amplitude in NTS neurons receiving baroreceptor afferents was lower in the RVH rats than in the sham rats and recovered after CIHH. The protein expression of nNOS and e NOS in the NTS was lower in the RVH rats than in the sham rats and this decrease was reversed by CIHH. In short, CIHH treatment decreases ABP in RVH rats via upregulating NOS expression in the NTS. 展开更多
关键词 Chronic intermittent hypobaric hypoxia RENAL VASCULAR HYPERTENSION Nitric oxide RENAL SYMPATHETIC nerve activity EXCITATORY POSTSYNAPTIC current
电压与电流相关测量中的去耦方法 预览
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作者 张东红 薄焕林 《自动化与仪表》 2019年第4期9-11,45共4页
在二端器件相关测量中,要同时精确测量其工作点的电压和电流是长期困扰人们的一个难题。其原因在于任何仪表都有自己的内阻。由于内阻的存在,无论怎样同时测量电压和电流,都会引入附加误差。这就使得一般的测量方法不可能达到同时精确... 在二端器件相关测量中,要同时精确测量其工作点的电压和电流是长期困扰人们的一个难题。其原因在于任何仪表都有自己的内阻。由于内阻的存在,无论怎样同时测量电压和电流,都会引入附加误差。这就使得一般的测量方法不可能达到同时精确测量电流和电压的目的。该文所介绍的方法是在测量电压的同时,用特殊的电路将电压表内阻对电流表引起的附加误差予以消除,从而达到同时精确测量二者的目的。 展开更多
关键词 相关测量 去耦 补偿测量 电压 电流
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Utilization of the superior properties of highly mesoporous PVP modified NiCo2O4 with accessible 3D nanostructure and flower-like morphology towards electrochemical methanol oxidation reaction 预览
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作者 Gracita M.Tomboc Medhen W.Abebe +1 位作者 Anteneh F.Baye Hern Kim 《能源化学:英文版》 SCIE EI CAS CSCD 2019年第2期136-146,共11页
Up to this date,researchers are still facing difficulties to expand the technology of direct methanol fuel cells(DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor perfor... Up to this date,researchers are still facing difficulties to expand the technology of direct methanol fuel cells(DMFCs) because of the high overpotential required to oxidize the methanol and its relatively poor performance due to CO poisoning of the leading-high cost anode catalyst.In line with this,we have successfully modified the morphological structure and composition of low cost cobalt based-metal oxides,MCo2O4(M = Zn and Ni),with the simple and noble use of polyvinyl pyrrolidone(PVP) as growth modifier and surface stabilizer during the synthesis of nanoparticles in our previous reports,which shown high electrocatalytic activity and strong stability.Due to the good performance of our PVP modified MCo2O4 towards pseudocapacitor and oxygen evolution reaction applications,we decided to extend our research study to methanol oxidation reaction.Remarkably,PVP modified Ni Co2O4 electrode directly grown on nickel foam substrate via a simple hydrothermal process exhibited better performance compared with PVP modified ZnCo2O4 and NiCo2O4 without PVP.It had obtained a remarkably low onset potential of 0.285 V and high current density of 280 m A cm-2,and shown great stability and high poison tolerance during a continuous CV cycling and Chronoamperometry test,which attained high efficiency of 86.86%and 98.52%,respectively.These positive results of PVP modified Ni Co2O4 electrode towards MOR might be attributed to its hierarchical 3 D nanostructures with highly mesoporous surface and large surface area which may have provided numerous electroactive sites,and the exceptional corrosion stability of Ni Co2O4 electrode in alkaline solution. 展开更多
关键词 NiCo2O4 3D NANOSTRUCTURE ELECTROCHEMICAL METHANOL oxidation Current density
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