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Orthogonal procrustes based semi-blind MIMO channel estimation under space-time block code transmissions

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The Journal of China Universities of Posts and Telecommunications 2011年第4期18卷 20-24页

作者： hu feng jin Li-biao LI Jian-zeng School of Information Engineering Communication University of China Beijing 100024 China

This work investigates a novel semi-blind channel estimation for multiple-input multiple-output （MIMO） space-time block coding （STBC） systems. Algorithms for channel estimation based on whitening-rotation （WR） decomposition that provides a combined quality and spatial scalability is utilized. Using a space-time code-constrained input design, our approach exploits the orthogonality of the signal and noise subspaces in conjunction with orthogonal procrustes （OP） technique to obtain an accurate estimate of the unitary rotation matrix and, consequently, of the channel parameters. Unitary rotation matrices are parameterized a much fewer number of parameters, and significant estimation gains can then be achieved by estimation of such orthogonal matrices. Furthermore, the proposed semi-blind MIMO channel estimation approach is conducted to reduce the complexity of system design when the number of the receive antennas is no less than the number of transmit antennas. Computer simulations are conducted to corroborate the effectiveness of the proposed channel estimation, and they demonstrate the improved performance compared to the existing training-based estimation.

关键词： MIMO semi-blind channel estimation STBC orthogonal procrustes singular value decomposition

黄龙病发病芦柑根际土壤细菌群落组成与多样性特征

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生物技术通报 2024年第2期40卷 266-276页

作者：雷美玲饶文华胡进锋岳琪吴祖建范国成福建农林大学植物保护学院福州350002 福建省农业科学院植物保护研究所福州350013

【目的】本研究旨在研究福建南平地区芦柑(Citrus reticulata)植株根际土壤细菌群落,并分析黄龙病对其细菌群落的影响,为南平地区芦柑黄龙病的防控提供科学依据。【方法】采用五点法采集了健康和黄龙病发病的芦柑植株根际土壤样本,通过... 详细信息

【目的】本研究旨在研究福建南平地区芦柑(Citrus reticulata)植株根际土壤细菌群落,并分析黄龙病对其细菌群落的影响,为南平地区芦柑黄龙病的防控提供科学依据。【方法】采用五点法采集了健康和黄龙病发病的芦柑植株根际土壤样本,通过扩增子测序技术和生物信息学方法,深入研究了黄龙病发病芦柑根际土壤细菌群落的多样性和组成变化,分析了土壤理化因子与细菌群落的关联性。【结果】研究结果表明,黄龙病发病的芦柑植株根际土壤细菌群落的多样性略高于健康植株。黄龙病发病芦柑根际土壤中的变形菌门相对丰度明显升高,而放线菌门相对丰度显著降低。在属水平上,与健康植株相比,黄龙病发病芦柑植株根际土壤细菌群落中蔷薇属和嗜酸性杆菌属的相对丰度显著增加,与速效钾、有效磷以及有机质呈现显著负相关,而与pH值呈现显著正相关。相反地,康奈斯氏杆菌属和褚氏杆菌属的相对丰度明显低于健康植株,并与速效钾、有效磷以及有机质呈现显著正相关,同时与p H值呈现显著负相关。【结论】黄龙病菌感染改变了柑橘土壤理化特性,并显著减少根际土壤中有益细菌的相对丰度,从而导致了芦柑植株根际细菌群落的多样性和组成出现显著变化。与此同时,黄龙病发病的芦柑植株可能通过招募固氮和促进植物根际生长的有益细菌来对抗病原菌的侵害。

关键词：黄龙病柑橘高通量测序根际土壤细菌群落差异物种环境因子

Advanced natural products chemistry research in China between 2015 and 2017

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Chinese Journal of Natural Medicines 2018年第12期16卷 881-906页

作者： YANG Guo-Xun MA Guang-Lei LI Hao huANG Ting XIONG Juan hu jin-feng Department of Natural Products Chemistry School of Pharmacy Fudan University

In this review, we intensively focus on the advances in research of natural products(NPs) discovery carried out by domestic scholars in China from 2015 through 2017. In general, a total of 1811 publications(1479 in English and 332 in Chinese) were accumulated regarding newly isolated NPs from plants, microorganisms, and marine sources. As a result, 277 selected papers concerning naturally occurring compounds with extraordinary frameworks, origins, and promising activities were discussed in this review article, mainly organized according to their structural classes and novelties.

关键词： Natural Products Chemistry Novel Structures Research Progress Review

血清Hcy、SOD、SDF-1与2型糖尿病患者远端对称性多发性神经病变的关系研究

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现代生物医学进展 2024年第16期24卷 3051-3055页

作者：胡金凤向娟冯京方媛崔蕊莉王倩倩徐敏解放军总医院京北医疗区内分泌科北京100089

目的:分析血清同型半胱氨酸(Hcy)、超氧化物歧化酶(SOD)、基质细胞衍生因子-1(SDF-1)与2型糖尿病(T2DM)患者远端对称性多发性神经病变(DSPN)的关系。方法:选择2020年1月至2023年1月我院收治的146例T2DM患者为研究对象,根据是否合并DSPN... 详细信息

目的:分析血清同型半胱氨酸(Hcy)、超氧化物歧化酶(SOD)、基质细胞衍生因子-1(SDF-1)与2型糖尿病(T2DM)患者远端对称性多发性神经病变(DSPN)的关系。方法:选择2020年1月至2023年1月我院收治的146例T2DM患者为研究对象,根据是否合并DSPN,分为伴DSPN(DSPN组)和不伴DSPN(NDSPN组),分别为65例和81例。收集两组患者的一般临床资料(饮酒史、吸烟史、年龄、糖尿病病程、体重指数、基线血压、性别等)及血糖、血脂等生化指标值,采用酶联免疫吸附法检测血清中的Hcy、SOD和SDF-1水平。比较两组患者的血清Hcy、SOD和SDF-1水平,分析不同病情严重程度患者的血清Hcy、SOD、SDF-1水平,分析三者与DSPN病变程度的相关性,并采用受试者工作曲线(ROC)分析三者在DSPN的临床诊断中的预测价值。结果:DSPN组患者的年龄、糖尿病病程和DBP均高于NDSPN组(P<0.05)。DSPN组患者的血清SOD和SDF-1水平均显著低于NDSPN组,而Hcy水平显著高于NDSPN组(P<0.05)。血清Hcy水平随着DSPN神经病变严重程度的加重而升高,而SOD、SDF-1水平随着病变程度的加重而降低(P<0.05)。多因素Logistic回归分析结果显示,患者年龄、糖尿病病程及血清SOD、Hcy、SDF-1水平均为DSPN的独立影响因素(P<0.05)。血清Hcy、SOD和SDF-1水平预测T2DM患者合并DSPN的曲线下面积(AUC)分别为0.793、0.801和0.840,三者联合预测的AUC值(0.877)均高于三者单独预测DSPN的AUC值。结论:血清Hcy、SOD、SDF-1均可能参与DSPN的发生发展进程,为DSPN发生的独立影响因素,联合检测对于DSPN的临床诊断具有较高的预测价值。

关键词： 2型糖尿病 Hcy SOD SDF-1 远端对称性多发性神经病变

Pitting corrosion initiated by SiO2-MnO-Cr2O3-Al2O3-based inclusions in a 304 stainless steel

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JOURNAL OF IRON AND STEEL RESEARCH INTERNATIONAL 2024年第9期31卷 2281-2293页

作者： hu, jin-zhen Li, Shi Zhang, Ji Ren, Ying Zhang, Li-feng Univ Sci & Technol Beijing USTB Sch Met & Ecol Engn Beijing 100083 Peoples R China Yanshan Univ Sch Mech Engn Qinhuangdao 066004 Hebei Peoples R China Baoshan Iron & Steel Co Ltd Stainless Steel R&D Ctr Cent R&D Inst Shanghai 201900 Peoples R China North China Univ Technol Sch Mech & Mat Engn Beijing 100144 Peoples R China

The influence of the aluminum content on the pitting corrosion of a 304 stainless steel by a Cl- solution was investigated. The number, area, and composition of non-metallic inclusions were modified by the addition of aluminum in the steel, which was responsible for the variation of the corrosion degree of the 304 stainless steel. Inclusions detection, corrosion test, electrochemical test, thermodynamic calculation, and first-principles calculation were performed to evaluate the pitting corrosion of the stainless steel. The initiation of the pitting corrosion by three types of inclusions, including (Mn, Si, Cr, S)O, (Mn, Al, Cr)O, and Al2O3 were in-situ observed. After corroding for 880 min, the corrosion index of (Mn, Si, Cr, S)O, (Mn, Al, Cr)O, and Al2O3 was 0.38%, 0.02%, and 0.00% min(-1), respectively. With the increase in aluminum content in the steel, the pitting potential of the stainless steel was 0.131, 0.304, and 0.338 V, respectively, indicating that a higher aluminum content in the steel was beneficial to improving the pitting corrosion resistance of the 304 stainless steel.

关键词： Pitting corrosion 304 stainless steel Non-metallic inclusion First-principles calculation Galvanic corrosion AUSTENITIC STAINLESS-STEEL SULFIDE INCLUSIONS BAND-STRUCTURE LOCALIZED CORROSION PIT INITIATION MNS INCLUSIONS BEHAVIOR MECHANISM SULFUR 1ST-PRINCIPLES

A CNN-SVR model for NO_(2)profile prediction based on MAX-DOAS observations:The influence of Chinese New Year overlapping the 2020 COVID-19 lockdown on vertical distributions of tropospheric NO_(2)in Nanjing,China

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Journal of Environmental Sciences 2024年第7期141卷 151-165页

作者： Xin Tian Zijie Wang Pinhua Xie jin Xu Ang Li Yifeng Pan feng hu Zhaokun hu Mingsheng Chen Jiangyi Zheng Information Materials and Intelligent Sensing Laboratory of Anhui Province Institutes of Physical Science and Information TechnologyAnhui UniversityHefei 230601China Key laboratory of Environmental Optical and Technology Anhui Institute of optics and Fine MechanicsHefei Institutes of Physical ScienceChinese Academy of SciencesHefei 230031China School of Environmental Science and Optoelectronic Technology University of Science and Technology of ChinaHefei 230026China

In this study,a hybrid model,the convolutional neural network-support vector regression model,was adopted to achieve prediction of the NO_(2)profile in Nanjing from January 2019to March *** the sudden decline in NO_(2)in February 2020,the contribution of the Coronavirus Disease-19(COVID-19)lockdown,Chinese New Year(CNY),and meteorologi cal conditions to the reduction of NO_(2)was ***_(2)vertical column densities(VCDs) from January to March 2020 decreased by 59.05%and 32.81%,relative to the same period in 2019 and 2021,*** the period of 2020 COVID-19,the average NO_(2)VCDs were 50.50%and 29.96%lower than those during the pre-lockdown and post-lockdown pe riods,*** NO_(2)volume mixing ratios(VMRs)during the 2020 COVID-19 lock down significantly decreased below 400 *** NO_(2)VMRs under the different wind fields were significantly lower during the lockdown period than during the pre-lockdown period This phenomenon could be attributed to the 2020 COVID-19 *** NO_(2)VMRs be fore and after the CNY were significantly lower in 2020 than in 2019 and 2021 in the same period,which further proves that the decrease in NO_(2)in February 2020 was attributed to the COVID-19 *** source analysis of an NO_(2)pollution episode during the lockdown period showed that the polluted air mass in the Beijing-Tianjin-Hebei was trans ported southwards under the action of the north wind,and the subsequent unfavorable meteorological conditions(local wind speed of<2.0 m/sec)resulted in the accumulation o pollutants.

关键词： MAX-DOAS CNN-SVR Nitrogen dioxide COVID-19 Chinese New Year Regional transport

Inhibition of chemokine-like factor 1 improves bloodbrain barrier dysfunction in rats following focal cerebral ischemia

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中国药理学与毒理学杂志 2016年第10期30卷 1024-1025页

作者： KONG Ling-lei hu jin-feng YUAN Yu-he CHEN Nai-hong DU Guan-hua State Key Laboratory of Bioactive Substances and Functions of Natural Medicines Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical College Beijing Key Laboratory of Drug Target and Screening Research Institute of Materia MedicaChinese Academy of Medical Sciences and Peking Union Medical College

OBJECTIVE To investigate the role of chemokine-like factor 1(CKLF1),a novel C-C chemokine,on brain-blood barrier(BBB)integrity in rat focal cerebral ischemia and reperfusion *** Antibodies against CKLF1 was applied to the rightcerebral ventricle immediately after transient middle cerebral artery *** water content,Evans blue leakage and the expression of aquaporin-4(AQP-4),matrix metalloproteinase-9(MMP-9),zonula occludens-1(ZO-1)and occludin were *** After treatment with antiCKLF1 antibody,brain water content and Evans blue leakage in ipsilateral hemisphere were decreased in a dose-dependent manner at 24 h after reperfusion,but not changed in contralateral ***-CKLF1 antibody reduced the expression of AQP-4 and MMP-9,and upregulated the expression of ZO-1 and *** results suggest that CKLF1 is involved in BBB disruption after *** Inhibition of CKLF1 protects against cerebral ischemia by maintaining BBB integrity,possibly via inhibiting the expression of AQP-4 and MMP-9,and increasing the expression of tight junction protein.

关键词： chemokine-like factor 1 cerebral ischemia brain-blood barrier

Dynamic characteristics and application of dual throat fluidic thrust vectoring nozzle

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Chinese Journal of Aeronautics 2024年第9期37卷 85-99页

作者： Buxian XU Dongping hu Lihao feng Fluid Mechanics Key Laboratory of Ministry of Education Beihang UniversityBeijing 100191China State Key Laboratory of Clean and Efficient Turbomachinery Power Equipment Dongfang Electric Corporation Dongfang Turbine Co.LTDDeyang 618000China

Thrust vectoring technology plays an important role in improving the maneuverability of *** order to overcome the disadvantages of mechanical thrust vectoring nozzles,such as complications of structure and significant increases in weight and cost,fluidic thrust vectoring noz-zles are *** Throat fluidic thrust vectoring Nozzle(DTN)has received wide attention due to its excellent thrust vectoring efficiency and minimal thrust *** this study,three-dimensional unsteady numerical simulations of a single axisymmetric DTN are conducted first to analyze its dynamic *** the pitch and yaw control characteristics of DTN equipped on a flying-wing aircraft are *** is found that the dynamic response will experience three stages:rapid-deflecting stage,oscillating stage,and steady stage.A complete recirculation zone forms at the end of the rapid-deflecting stage,which pushes the primary flow to attach to the wall opposite the secondary ***,the exhaust flow is *** terms of DTN's appli-cation,the DTN equipped on the flying-wing aircraft is capable of providing effective pitch and yaw moments at all angles of attack and Mach *** addition,continuous pitch and yaw moments can be obtained by adjusting the secondary mass flow *** control moment is gen-erated due to the asymmetrical pressure distribution of nozzle surface,which is mainly contributed by the pressure decrease on the secondary injection ***,the DTN equipped on the flying-wing aircraft has a relatively high thrust vectoring efficiency of around 5°/%and a thrust coefficient of around 0.95 when nozzle pressure ratio equals *** results provide an important theoretical basis for the practical application of DTN.

关键词： Dual throat nozzle Dynamic response charac-teristic Flowcontrol Flying-wing aircraft

Multi-Axis Attention With Convolution Parallel Block for Organoid Segmentation

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IEEE/CAA Journal of Automatica Sinica 2024年第5期11卷 1295-1297页

作者： Pengwei hu Xun Deng feng Tan Lun hu Xinjiang Technical Institute of Physics and Chemistry Chinese Academy of SciencesUrumqi 830011 University of Chinese Academy of Sciences Beijing 100049 Xinjiang Laboratory of Minority Speech and Language Information Processing Urumqi 830011China Merck KGaA Darmstadt 64293Germany

Dear Editor,This letter presents an organoid segmentation model based on multi-axis attention with convolution parallel *** adeptly captures dynamic dependencies within bright-field microscopy images,improving global ... 详细信息

关键词： letter convolution organo