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Effects of Typical Soil and Stratification Thickness on Water Infiltration Characteristics in Central Ningxia

Meteorological and Environmental Research 2024年第4期15卷 58-65页

作者： tianwen ZHANG Wei chen Xiaoying chen Rongjun ZHI Lin chen Haibo ZHANG Wei LIANG Ningxia Hui Autonomous Region Institute of Mineral Geology Yinchuan 750021China Key Laboratory of Restoration and Reconstruction of Degraded Ecosystems in Northwest China Ministry of Education(Ningxia University)Yinchuan 750021China College of Ecology and Environment Ningxia UniversityYinchuan 750021China

In order to compare the influence of different soil types and stratification on water infiltration capacity,two main types of soil in the desert steppe,sierozem(S)and aeolian sandy soil(A),were selected,and infiltration simulation tests were conducted on homogeneous soil and layered soil(layer thickness 5,10,and 20 cm),*** results show that during the whole experiment,there was a small difference between S5A95(aeolian sandy soil 95 cm thick was covered with sierozem 5 cm thick)and S10A90(aeolian sandy soil 90 cm thick was covered with sierozem 10 cm thick)in the wetting front process,infiltration rate and cumulative infiltration,but there was a significant difference between S5A95 and S20A80(aeolian sandy soil 80 cm thick was covered with sierozem 20 cm thick).In the initial infiltration stage,there was no significant difference between A5S95(sierozem 95 cm thick was covered with aeolian sandy soil 5 cm thick)and A10S90(sierozem 90 cm thick was covered with aeolian sandy soil 10 cm thick).However,with the increase of infiltration time,the wetting front process,A5S95,A10S90 and A20S80 had significant differences in terms of wetting front process,infiltration rate and cumulative *** infiltration capacity of A was significantly higher than that of *** with linear R 2 value and model parameters,the three infiltration models were comprehensively compared,and the fitting process and results of the general empirical model for the infiltration process of homogeneous soil and layered soil showed good *** models were used to simulate the water infiltration process of layered soil with different textures,and the order of the effect is as follows:general empirical model>Kostiakov model>Philip *** type and layer thickness had a great influence on water infiltration *** sierozem was covered with aeolian sandy soil 20 cm thick,the infiltration capacity was the *** aeolian sandy soil was covered with sierozem 10 cm thic

关键词： Soil type Layer thickness Water infiltration Desert steppe

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An Impedance Analysis based Active Damping Control Strategy for Parallel Voltage-Controlled Inverters

An Impedance Analysis based Active Damping Control Strategy ...

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第37届中国控制会议

作者： Lifeng Li Laijun chen tianwen Zheng Yan Guo State Key Lab of Power System Department of Electrical EngineeringTsinghua University Sichuan Energy Internet Research Institute Tsinghua University

In view of the fact that inverters using LCL filter have been widely adopted in power systems,resonance caused by LCL filter in parallel-inverter-based system has become more and more *** order to stabilize the operation of the paralleled inverter system and improve the waveform of the injected currents,a resonance suppression method is ***,based on the stability analysis of the corresponding mathematical model,the resonance frequency that occurs in a parallel-inverter-based system is ***,a notch filter is selected on the basis of the resonance characteristics,which is adopted to improve the damping of the system and enhance the *** tests validate the stability analysis and the performance of the proposed control strategy.

关键词： Voltage-Controlled inverters LCL filter resonance suppression

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How to Evaluate the Rice Cultivation Suitability?

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Asian Agricultural Research 2013年第12期5卷 59-64页

作者： Wenxi LI Yueping ZHANG Changsong WANG Wei MAO tianwen HANG Ming chen Bingning ZHANG Yangzhou Station of Soil and Fertilizer Yizheng Station of Soil and Fertilizer

To rationally allocate farmland resources,and scientifically make farming industrial planning,we take Yizheng City in Jiangsu Province as the research object,and select 13 *** on Farmland Resources Management Information System in Yizheng City,we establish AHP model,and membership function model,for the evaluation of farmland suitability of *** results show that the farmland area in the highly suitable areas accounts for 10.2%of the total farmland area;the farmland area in the suitable areas accounts for 56.08%of the total farmland area;the farmland area in the marginally suitable areas accounts for 25.50%of the total farmland area;the farmland area in the unsuitable areas accounts for 8.22%of the total farmland *** is significant positive correlation between the actual yield of rice surveyed and suitability index obtained through evaluation(R2=0.1964,319 samples);the actual yield of rice in the highly suitable areas is higher than in the marginally suitable areas and suitable areas,and the rice yield is the lowest in the unsuitable areas.

关键词： Rice Farmland suitability Suitability index Evalua

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Pinning Consensus Based Control with Fast Convergence for Isolated Microgrids Considering Communication Time Delays

Pinning Consensus Based Control with Fast Convergence for Is...

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第37届中国控制会议

作者： Sicheng Deng tianwen Zheng Yang Si Laijun chen Shengwei Mei State Key Lab of Power System Department of Electrical EngineeringTsinghua University Qinghai Key Lab of Efficient Utilization of Clean Energy (Qinghai University Tus-Institute for Renewable Energy)

Distributed control methods are widely employed in AC microgrids because of the robustness and flexibility. As a necessary part of the distributed control system, the communication network plays an important role in the microgrids. Communication time delays are unavoidable in communication networks. This paper focuses on the influence of communication time delays in microgrids. A traditional pinning consensus based control strategy for active power sharing in microgrids is investigated and the impact of communication time delays is analyzed. To speedup the convergence rate, a modified control strategy is proposed. With the same communication time delay, the modified strategy converges faster than the traditional strategy. Also,microgrids with the modified strategy could stand a larger time delay without losing stability. The effectiveness of the modified strategy is verified by simulation results.

关键词： Microgrid Active power sharing Pinning consensus Communication time delay

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Analysis of Cracking Reason and Optimization Design of the Heat Shield for an Automobile Exhaust Pipe

Analysis of Cracking Reason and Optimization Design of the H...

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2020中国汽车工程学会年会暨展览会

作者： Dai Pengfei Li tianwen chen Xiaodong Zhang Xiaotao Wang Chong Zhou Shuchao Powertrain R&D Institute Changan Automobile

Through fracture analysis,it is confirmed that the cracking of the exhaust pipe heat shield of the exhaust system is thermal fatigue *** this paper,the finite element analysis of the structure is carried out in detail,The thermo-solid coupling analysis shows that the maximum equivalent plastic strain amplitude is located at the cracked weld of the heat *** on this,the structure of the heat shield and the welding fixed position are *** experimental verification shows that the optimized structure meets the design requirements.

关键词： exhaust system heat shield temperature field thermo-solid coupling analysis equivalent plastic strain(PEEQ)

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Consensus-Based Distributed Control for Reactive Power Sharing in Autonomous Microgrid under Communication Noises

Consensus-Based Distributed Control for Reactive Power Shari...

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第37届中国控制会议

作者： Yuyang Wang Laijun chen Chunlai Li tianwen Zheng Libing Yang Shengwei Mei State Key Lab of Power System Department of Electrical Engineering Tsinghua University Qinghai Key Lab of Efficient Utilization of Clean Energy (Qinghai University Tus-Institute for Renewable Energy) Key Laboratory of Photovoltaic Power Generation and Grid-connected Technology (Qinghai Electrical Power Research Institute Qinghai Electric Power Corporation)

Distributed control relies on communication network among distributed generators（DGs）, which is commonly influenced by noises. Furthermore, reactive power deviations may be deteriorated under different communication noises. In this paper, an improved consensus-based distributed control considering communication noises is developed in AC autonomous microgrids, which is capable of attenuating the impact of noises. The traditional consensus-based distributed control is introduced and noises are also considered in traditional control. In order to attenuate the influence of noises, a consensus gain function is involved, which can attenuate the impacts in reactive power sharing. By using this proposed method, the proportional reactive power sharing is achieved under noises. Simulation results verify the effectiveness of the proposed method.

关键词： microgrid distributed control reactive power sharing consensus gain function communication noises

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Hematological Indices as Simple, Inexpensive and Practical Severity Markers of Obstructive Sleep Apnea Syndrome: a Meta-analysis

Hematological Indices as Simple, Inexpensive and Practical S...

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2018年（第四十届）浙江省医学会呼吸系病学术年会

作者： Mindan Wu Lingren Zhou Ding Zhu tianwen Lai Zhihua chen Huahao Shen Second Affiliated Hospital of Zhejiang University School of Medicine

Objective :To analyze the correlation between hematological indices and the severity of Obstructive Sleep Apnea Syndrome(OSAS).Method: Medical databases were searched included Pubmed, Web of Science, Scopus, Cochrane Library, Clinical Trial, Embase and Google Scholar(up to October 29, 2017). We used weighted mean differences(WMDs) with 95% confidence intervals(CIs) from random-effects *** :: Seventeen studies were included in this meta-analysis and Results : were presented by different hematological parameters. Pooled analysis showed that OSAS was associated with a high level of WBC(white blood cell, 11 studies, 2206 subjects, WMD: 0.58;95%CI 0.31 to 0.85;p < 0.0001), NLR(neutrophil-to-lymphocyte ratio, 5 studies, 1416 subjects, WMD: 0.46;95%CI 0.13 to 0.80;p=0.007),MPV(mean platelet volume, 8 studies, 1854 subjects, WMD: 0.63;95%CI 0.29 to 0.98;p=0.0004),PDW(platelet distribution width, 6 studies, 1911 subjects, WMD: 0.76;95%CI 0.47 to 1.06;p < 0.00001), PLR(platelet-to-lymphocyte ratio, 3 studies, 998 subjects, WMD: 21.76;95%CI 8.54 to 34.99;p=0.001),RDW(red cell distribution width, 5 studies, 1701 subjects, WMD: 0.31;95%CI 0.11 to 0.51;p=0.002) and HCT(hematocrit, 3 studies, 662 subjects, WMD: 1.58;95%CI 0.52 to 2.64;p=0.003). But OSAS was associated with a low level of LYM(lymphocyte, 5 studies, 1285 subjects, WMD:-0.27;95%CI-0.49 to-0.06;p=0.01). There was a gradual rising trend from mild OSAS to severe OSAS existed in all *** :Hematological indices are comparatively Simple, Inexpensive and Practical Severity Markers of OSAS including WBC, LYM, NLR, MPV, PDW, PLR, RDW and HCT.

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参量声源自解调信号失真研究

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仪器仪表学报 2013年第8期34卷 1771-1778页

作者：杨天文黄大贵陈敏张富东陈祥电子科技大学机械电子工程学院成都611731 电子科技大学航空航天学院成都611731

针对参量声源自解调信号失真问题,根据"Berktay远场解"对其进行了理论分析,并通过实验对理论分析结果进行了验证,发现:"Berktay远场解"对自解调信号中的基频、差频可以较准确地预测,而对导致信号失真的主要因素如二次谐波、和频等的预... 详细信息

针对参量声源自解调信号失真问题,根据"Berktay远场解"对其进行了理论分析,并通过实验对理论分析结果进行了验证,发现:"Berktay远场解"对自解调信号中的基频、差频可以较准确地预测,而对导致信号失真的主要因素如二次谐波、和频等的预测误差很大,不能作为失真分析的精确依据;差频不是导致参量声源自解调信号失真的主要原因,降低失真的有效途径是减小自解调信号中二次谐波、和频分量,从而使有害频率成分的数量及幅值得到有效抑制。本项研究揭示了导致参量声源自解调信号失真的主要因素及其变化规律,可为参量声源信号处理方法的研究提供有益参考。

关键词：参量声源自解调信号失真分析 Berktay远场解信号处理

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四象限探测器位置检测精度的主要影响因素研究

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中国激光 2015年第12期42卷 298-306页

作者：张辉陈云善耿天文吴佳彬陈涛中国科学院长春光学精密机械与物理研究所吉林长春130033 中国科学院大学北京100049

为了提高四象限探测器(QD)光斑位置检测性能,研究了在高斯光斑模型下影响QD位置检测精度的主要因素。分析了四象限探测器位置检测的基本原理,随后根据误差理论推导出高斯光斑模型下位置检测精度与光斑半径、质心位置和系统信噪比关系的... 详细信息

为了提高四象限探测器(QD)光斑位置检测性能,研究了在高斯光斑模型下影响QD位置检测精度的主要因素。分析了四象限探测器位置检测的基本原理,随后根据误差理论推导出高斯光斑模型下位置检测精度与光斑半径、质心位置和系统信噪比关系的数学模型,通过数值仿真和实验分析验证了该数学模型的有效性,并深入分析了各因素对位置检测精度影响的趋势及大小。研究结果表明,对于四象限探测器高斯光斑位置检测系统,在保证检测范围的条件下,采用较小半径的光斑、选取靠近光敏面中心的工作区域和提高系统信噪比可以提高位置检测精度。当系统信噪比为57.48 d B时,采用束腰半径为0.6 mm的高斯光斑,QD中心点位置检测精度可达0.514μm。

关键词：测量四象限探测器检测精度高斯光斑信噪比

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Improved methodology for efficient establishment of the myocardial ischemia-reperfusion model in pigs through the median thoracic incision

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The Journal of Biomedical Research 2023年第4期37卷 302-312页

作者： Liuhua Zhou Jiateng Sun Tongtong Yang Sibo Wang Tiankai Shan Lingfeng Gu Jiawen chen tianwen Wei Di Zhao Chong Du Yulin Bao Hao Wang Xiaohu Lu Haoliang Sun Meng Lv Di Yang Liansheng Wang Department of Cardiology the First Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsu 210029China Department of Cardiac Surgery the First Affiliated Hospital of Nanjing Medical UniversityNanjingJiangsu 210029China Medical Experimental Animal Center Nanjing Medical UniversityNanjingJiangsu 210029China

To investigate the feasibility and effectiveness of establishing porcine ischemia-reperfusion models by ligating the left anterior descending(LAD)coronary artery,we first randomly divided 16 male Bama pigs into a sham group and a model *** anesthesia,we separated the arteries and ***,we rapidly located the LAD coronary artery at the beginning of its first diagonal branch through a mid-chest ***,we loosened and released the ligation line after five minutes of ***,we ligated the LAD coronary artery in situ two minutes later and loosened the ligature 60 min after *** with the sham group,electrocardiogram showed multiple continuous lead ST-segment elevations,and ultrasound cardiogram showed significantly lower ejection fraction and left ventricular fractional shortening at one hour and seven days post-operation in the model ***-four hours after the operation,cardiac troponin T and creatine kinase-MB isoenzyme levels significantly increased in the model group,compared with the sham *** and eosin staining showed the presence of many inflammatory cells infiltrating the interstitium of the myocardium in the model group but not in the sham *** staining revealed a significant increase in infarct size in the ischemia/reperfusion *** eight pigs in the model group recovered with normal sinus heart rates,and the survival rate was 100%.In conclusion,the method can provide an accurate and stable large animal model for preclinical research on ischemia/reperfusion with a high success rate and homogeneity of the myocardial infarction area.

关键词： coronary artery ligation myocardial ischemia-reperfusion injury Bama pig animal model

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