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Path loss model based on cluster at 28 GHz in the indoor and outdoor environments

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Science China(Information Sciences) 2017年第8期60卷 25-35页

作者： lai zhou Limin XIAO Zhi YANG Jiahui LI Jin LIAN Shidong zhou State Key Laboratory on Microwave and Digital Communications Tsinghua University Tsinghua National Laboratory for Information Science and Technology Tsinghua University Department of Engineering Physics Tsinghua University Department of Electronic Engineering Tsinghua University

This paper presents 28 GHz path loss model based on cluster obtained from channel measurement campaigns with rotating platforms and directional antennas in the indoor and outdoor environments. The transmitter(TX) and receiver(RX) both sweep a large range of angles in the azimuth and elevation plane on account of covering main propagation paths and measuring burden. As the sequence number of cluster increases, the path loss exponents(PLEs) increase while shadow factors also have a growing tendency. The PLE of all-clusters is the least because of multi propagation paths, and the LOS PLEs of corridor scenario are less compared with that of office scenario because of corridor’s long and narrow structure. This improved model not only considers cluster characteristics, but also unites directional and omnidirectional models into the same framework, which to some extent improves the 5G mm Wave channel model.

关键词： mm Wave channel measurement office and corridor rotating platform multipath components path loss model based on cluster

Corrosion Resistance of Sintered NdFeB Permanent Magnet With Ni-P/TiO_2 Composite Film

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Journal of Iron and Steel Research International 2009年第3期16卷 89-94页

作者： SONG lai-zhou YANG Zhi-yong Department of Environment and Chemical Engineering Yanshan University Qinhuangdao 066004 HebeiChina Central Iron and Steel Research Institute Beijing 100081 China

The Ni-P/TiO2 composite film on sintered NdFeB permanent magnet was investigated by X-ray diffraction （XRD）,environmental scanning electron microscopy （ESEM）,and energy dispersive X-ray spectrometer （EDX）. The corrosion resistance of Ni-P/TiO2 film coated on NdFeB magnet,in 0.5 mol/L NaCl solution,was studied by potentiodynamic polarization,salt spray test and electrochemical impedance spectroscopy （EIS） techniques. The self-corrosion current density （icorr） and the polarization resistance （Rp） of Ni-P/TiO2 film are 0.22 μA/cm2 （about 14% of that of Ni-P coating）,and 120 kΩ·cm2 （about 2 times of that of Ni-P coating）,respectively. The anti-salt spray time of Ni-P/TiO2 film is about 2.5 times of that of the Ni-P coating. The results indicate that Ni-P/TiO2 film has a better corrosion resistance than Ni-P coating,and the composite film increases the corrosion resistance of NdFeB magnet markedly.

关键词： sintered NdFeB permanent magnet Ni-P/TiO2 composite film sodium chloride solution corrosion resistance

Correlation between exercise, personal income level and health-related quality of life in patients with newly diagnosed stable angina

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Military Medical Research 2020年第1期7卷 63-70页

作者： Yi Wang Lei Huang lai-Xin zhou Department of Cardiology the Second Affiliated Hospital of Army Medical UniversityChongqing 400037China Division of Medical Affairs the Second Affiliated Hospital of Army Medical UniversityChongqing 400037China The First Affiliated Hospital of Army Medical University Chongqing 400038China

Background:Stable angina is one of the most common clinical types of coronary artery disease(CAD)and associated with poor health-related quality of life(HRQL).However,few studies have evaluated the risk factors associated with HRQL in patients with newly diagnosed stable ***:A cross-sectional survey was conducted with 342 consecutive outpatients with newly diagnosed stable angina from October 2017 to January 2018 at the Second Affiliated Hospital of Army Medical University,Chongqing,*** dimensions of HRQL were evaluated via the 36-item Short-Form Health Survey,including physical functioning,role limitation due to physical problems,bodily pain,general health,vitality,social functioning,role limitation due to emotional problems,and mental *** and mental component summaries were *** stepwise regression was performed to determine the factors associated with ***:Patients who were older,were females,did not exercise,had lower educational levels,had lower monthly incomes,had smoking/drinking habits,and had diabetes,hypertension,or hyperlipemia showed lower physical HRQL scores,while those who were older with lower educational levels and lower monthly incomes showed lower mental HRQL *** results of the multiple stepwise regression analyses showed that physical and mental HRQL were positively correlated with exercise and monthly income and negatively associated with *** with monthly income≥5000 Yuan showed higher HRQL scores than those with monthly income<5000 *** quality and drinking were negatively associated with physical,but not mental ***:Our findings indicated that exercise and personal income level,both modifiable factors,were positively associated with physical and mental *** findings could have implications for clinical suggestions and strategies to improve HRQL in patients with stable angina.

关键词： Coronary outpatients Exercise Health-related quality of life Monthly income

Association of chronic obstructive pulmonary disease with mild cognitive impairment and dementia risk:A systematic review and meta-analysis

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World Journal of Clinical Cases 2022年第11期10卷 3449-3460页

作者： Li-Ying Zhao Xue-lai zhou Department of Geriatrics Traditional Chinese Medical Hospital of ZhujiZhuji 311800Zhejiang ProvinceChina Department of Respiratory Medicine Traditional Chinese Medical Hospital of ZhujiZhuji 311800Zhejiang ProvinceChina

BACKGROUND Chronic obstructive pulmonary disease(COPD)is a common public health issue that has been linked to cognitive *** To investigate the relationship between COPD and a risk of mild cognitive impairment(MCI)and *** A comprehensive literature search of the PubMed,Embase,Google Scholar,and Cochrane Library electronic databases was *** odds ratios(OR)and mean differences(MD)with 95%confidence intervals(CIs)were calculated using a random or fixed effects *** that met the inclusion criteria were assessed for quality using the Newcastle Ottawa *** Twenty-seven studies met all the inclusion ***-analysis yielded a strong association between COPD and increased risk of MCI incidence(OR=2.11,95%CI:1.32-3.38).It also revealed a borderline trend for an increased dementia risk in COPD patients(OR=1.16,95%CI:0.98-1.37).Pooled hazard ratios(HR)using adjusted confounders also showed a higher incidence of MCI(HR=1.22,95%CI:-1.18 to-1.27)and dementia(HR=1.32,95%CI:-1.22 to-1.43)in COPD patients.A significant lower mini-mental state examination score in COPD patients was noted(MD=-1.68,95%CI:-2.66 to-0.71).CONCLUSION Our findings revealed an elevated risk for the occurrence of MCI and dementia in COPD *** clinical management and attention are required to prevent and control MCI and dementia incidence in COPD patients.

关键词： Mild cognitive impairment Chronic obstructive pulmonary disease Dementia Meta-analysis

Low-amplitude structure recognition method based on non-subsampled contourlet transform

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Petroleum Science 2024年第5期21卷 3062-3078页

作者： Fen Lyu Xing-Ye Liu Li Chen Chao Li Jie zhou Huai-lai zhou Key Lab of Earth Exploration&Information Techniques of Ministry of Education Chengdu University of TechnologyChengdu610059SichuanChina College of Geophysics Chengdu University of TechnologyChengdu610059SichuanChina State Key Laboratory of Oil and Gas Reservoir Geology and Exploitation Chengdu University of TechnologyChengdu610059SichuanChina Postdoctoral Research Station of the School of Geophysics Chengdu University of TechnologyChengdu610059SichuanChina

Currently, horizontal well fracturing is indispensable for shale gas development. Due to the variable reservoir formation morphology, the drilling trajectory often deviates from the high-quality reservoir,which increases the risk of fracturing. Accurately recognizing low-amplitude structures plays a crucial role in guiding horizontal wells. However, existing methods have low recognition accuracy, and are difficult to meet actual production demand. In order to improve the drilling encounter rate of high-quality reservoirs, we propose a method for fine recognition of low-amplitude structures based on the non-subsampled contourlet transform(NSCT). Firstly, the seismic structural data are analyzed at multiple scales and directions using the NSCT and decomposed into low-frequency and high-frequency structural components. Then, the signal of each component is reconstructed to eliminate the low-frequency background of the structure, highlight the structure and texture information, and recognize the low-amplitude structure from it. Finally, we combined the drilled horizontal wells to verify the low-amplitude structural recognition results. Taking a study area in the west Sichuan Basin block as an example, we demonstrate the fine identification of low-amplitude structures based on NSCT. By combining the variation characteristics of logging curves, such as organic carbon content(TOC), natural gamma value(GR), etc., the real structure type is verified and determined, and the false structures in the recognition results are checked. The proposed method can provide reliable information on low-amplitude structures for optimizing the trajectory of horizontal wells. Compared with identification methods based on traditional wavelet transform and curvelet transform, NSCT enhances the local features of low-amplitude structures and achieves finer mapping of low-amplitude structures, showing promise for application.

关键词： Shale gas Low-amplitude structure Low-frequency background Non-subsampled contourlet transform Horizontal well verification

Modification and Anticorrosion Property of Carbon Steel with TiO_2 Film

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Journal of Iron and Steel Research International 2005年第6期12卷 37-41页

作者： SONG lai-zhou ZHAO Jing WANG Xiu-li Yanshan University Qinhuangdao 066004 China

A new TiO2 modified film on carbon steel was prepared by electroless plating and sol gel composite process. An artificial neural net was used to optimize the preparing condition of the film. The optimized condition of the TiO2-modified film on carbon steel is as follows： plating time of NiP is 50 min, number of dip coating is 4, heat treatment time is 2 h, and the molar ratio of complexing reagent to Ti（OC4 H9）4 is 1.5 ： 1. Corrosion behavior of carbon steel with coating was investigated by polarization resistance measurement, anode polarization, EIS and ESEM measurement. XPS was used to characterize the element valence of the modified film. Results show that carbon steel with TiO2 modified film has good corrosion resistance in 0.5 mol/L of H2SO4 solution and 0.5 mol/L of NaCl solution. It is also found that the preparing condition of forming TiO2-modified film can be obtained easily by the artificial neural net.

关键词： electroless plating sol-gel composite process artificial neural net TiO2-modified film corrosion resistance

Preventive effects of chitosan on peritoneal adhesion in rats

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World Journal of Gastroenterology 2006年第28期12卷 4572-4577页

作者： Zhi-Liang Zhang Si-Wei Xu Xie-lai zhou School of Clinical Medicine Hangzhou Teachers College Hangzhou 310036 Zhejiang Province China Department of Cardiovascular Surgery The 2nd Affiliated Hospital of Medical College of Zhejiang University Hangzhou 310009 Zhejiang Province China

AIM： To study the effects of chitosan gel and blending chiston/gelatin film on preventing peritoneal adhesion in rats. METHODS： SD rats were randomly divided into 2 groups, group A treated with chitosan gel and group B with blending chiston/gelatin film. In group A, rats were randomly subdivided into 3 subgroups as groups A1, A2 and A3, and different methods were used to induce peritoneal adhesions at the dead end of vermiform process in each group as follows： Group A1 with trauma, A2 with talc powder and A3 with ligation of blood vessel. In each subgroup, rats were redivided into control group and experimental group whose treated vermiform processes were respectively coated with chitosan gel and normal saline immediately after the adhesioninduced treatments. In group B, all the rats received traumatic adhesion-induced treatments and then were randomly divided into 4 groups （groups B1, B2, B3, B4）. Group B1 served as control group and were coated with normal saline in the vermiform processes immediately after the treatments, and groups B2, B3 and B4 with 100% chitosan film, chitosan film containing 10% gelatin and chiston film containing 50% gelatin, respectively. At 2 and 4 wk after the above treatments, half of the rats in each terminal group were belly opened, and the peritoneal adhesive situation was graded and histopathological changes were examined. RESULTS：（1） In group A, regarding peritoneal adhesion situation： At both 2 and 4 wk after the treatments, for groups A1 and A3, the adhesive grades of experimental groups were significantly lower than those of the control group （2 wk： H = 4.305, P 〈 0.05 for A1, H = 6.743, P 〈 0.01 for A3; 4 wk： H = 4.459, P 〈 0.05 for A1, H =4.493, P 〈 0.05 for A3）. However, of group A2, there was no significant difference between the experimental and control groups （2 wk： H = 0.147, P 〉 0.05; 4 wk： H = 1.240, P 〉 0.05）. Regarding pathological changes： In groups A1 and A3, the main pathological change was fibroplasia. In group A2

关键词： Chitosan Gelatin Peritoneal adhesion Rat

Optimal Day-ahead Scheduling of Islanded Microgrid Considering Risk-based Reserve Decision

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Journal of Modern Power Systems and Clean Energy 2021年第5期9卷 1149-1160页

作者： Zehuai Liu Siliang Liu Qinhao Li Yongjun Zhang Wenyang Deng lai zhou School of Electric Power South China University of TechnologyGuangdong Key Laboratory of Clean Energy TechnologyGuangzhouChina Dongguan Power Supply Bureau of Guangdong Power Grid Co. Ltd.DongguanChina Guangzhou Power Electrical Technology Co. Ltd.GuangzhouChina

Due to the lack of support from the main grid,the intermittency of renewable energy sources(RESs)and the fluctuation of load will derive uncertainties to the operation of islanded microgrids(IMGs).It is crucial to allocate appropriate reserve capacity for the economic and reliable operation of *** the high penetration of RESs,it faces both economic and environmental challenges if we only use spinning reserve for reserve *** solve these problems,a multi-type reserve scheme for IMGs is proposed according to different operation characteristics of generation,load,and *** operation risk due to reserve shortage is modeled by the conditional value-at-risk(CVaR)*** correlation of input variables is considered for the forecasting error modeling of RES and load,and Latin hypercube sampling(LHS)is adopted to generate the random scenarios of the forecasting error,so as to avoid the dimension disaster caused by conventional large-scale scenario sampling ***,an optimal day-ahead scheduling model of joint energy and reserve considering riskbased reserve decision is established to coordinate the security and economy of the operation of ***,the comparison of numerical results of different schemes demonstrate the rationality and effectiveness of the proposed scheme and model.

关键词： Day-ahead scheduling risk-based reserve decision conditional value-at-risk(CVaR) renewable energy source(RES) islanded microgrids

Numerical Si mulation of Inner Stress Fields for Stretching Block With Rectangular Section Between Flat Anvils

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Journal of Iron and Steel Research International 2006年第1期13卷 75-78页

作者： DENG Dong-mei LIU Zhu-bai zhou lai-shui College of Mechanical and Electrical Engineering Nanjing University of Aeronautics and Astronautics Nanjing 210016Jiangsu China College of Mechanical Engineering Yanshan University Qinhuangdao 066004 Hebei China

The stretch of blocks with rectangular section using flat anvils was simulated by using ANSYS software. The inner stress distribution for different tool width ratio w/h and blank width ratio b/h was studied. Consequent- ly, critical anvil width ratio （w/h）c and critical blank width ratio （b/h）c are obtained, which provide a sound basis for designing reasonable stretching technology.

关键词： stretching flat anvil anvil width ratio blank width ratio transverse stress axial stress