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20篇 您的检索式:作者名="LI Yanwu"
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1Multivariate analysis of surface water quality in the Three Gorges area of China and implications for water management显示文摘Multivariate statistical techniques,cluster analysis,non-parametric tests,and factor analysis were applied to analyze a water quality dataset including 13 parameters at 37 sites of the Three Gorges area,China,from 2003–2008 to investigate spatio-temporal variations and identify potential pollution sources.Using cluster analysis,the twelve months of the year were classified into three periods of lowflow (LF),normal-flow (NF),and high-flow (HF);and the 37 monitoring sites were divided into low pollution (LP),moderate pollution (MP),and high pollution (HP).Dissolved oxygen (DO),potassium permanganate index (COD Mn ),and ammonia-nitrogen (NH 4 +-N) were identified as significant variables affecting temporal and spatial variations by non-parametric tests.Factor analysis identified that the major pollutants in the HP region were organic matters and nutrients during NF,heavy metals during LF,and petroleum during HF.In the MP region,the identified pollutants primarily included organic matter and heavy metals year-around,while in the LP region,organic pollution was significant during both NF and HF,and nutrient and heavy metal levels were high during both LF and HF.The main sources of pollution came from domestic wastewater and agricultural activities and runoff;however,they contributed differently to each region in regards to pollution levels.For the HP region,inputs from wastewater treatment plants were significant;but for MP and LP regions,water pollution was more likely from the combined effects of agriculture,domestic wastewater,and chemical industry.These results provide fundamental information for developing better water pollution control strategies for the Three Gorges area.Jian Zhao Guo Fu Kun Lei Yanwu Li 2011Journal of Environmental Sciences2011,23,9:25
2Development of Land Surface Model BCC_AVIM2.0 and Its Preliminary Performance in LS3MIP/CMIP6显示文摘The improvements and validation of several parameterization schemes in the second version of the Beijing Climate Center Atmosphere–Vegetation Interaction Model(BCC_AVIM2.0) are introduced in this study. The main updates include a replacement of the water-only lake module by the common land model lake module(Co LM-lake) with a more realistic snow–ice–water–soil framework, a parameterization scheme for rice paddies added in the vegetation module, renewed parameterizations of snow cover fraction and snow surface albedo to accommodate the varied snow aging effect during different stages of a snow season, a revised parameterization to calculate the threshold temperature to initiate freeze(thaw) of soil water(ice) rather than being fixed at 0°C in BCC_AVIM1.0, a prognostic phenology scheme for vegetation growth instead of empirically prescribed dates for leaf onset/fall, and a renewed scheme to depict solar radiation transfer through the vegetation canopy. The above updates have been implemented in BCC_AVIM2.0 to serve as the land component of the BCC Climate System Model(BCC_CSM). Preliminary results of BCC_AVIM in the ongoing Land Surface, Snow, and Soil Moisture Model Intercomparison Project(LS3 MIP) of the Coupled Model Intercomparison Project Phase 6(CMIP6) show that the overall performance of BCC_AVIM2.0 is better than that of BCC_AVIM1.0 in the simulation of surface energy budgets at the seasonal timescale. Comparing the simulations of annual global land average before and after the updates in BCC_AVIM2.0 reveals that the bias of net surface radiation is reduced from-12.0 to-11.7 W m-2 and the root mean square error(RMSE) is reduced from 20.6 to 19.0 W m-2;the bias and RMSE of latent heat flux are reduced from 2.3 to-0.1 W m-2 and from 15.4 to14.3 W m-2, respectively;the bias of sensible heat flux is increased from 2.5 to 5.1 W m-2 but the RMSE is reduced from 18.4 to 17.0 W m-2.Weiping LI Yanwu ZHANG Xueli SHI Wenyan ZHOU Anning HUANG Mingquan MU Bo QIU Jinjun JI 2019Journal of Meteorological Research2019,33,5:14
3Synthesis of Isotopically-Labeled Graphite Films by Cold-Wall Chemical Vapor Deposition and Electronic Properties of Graphene Obtained from Such Films显示文摘We report the synthesis of isotopically-labeled graphite films on nickel substrates by using cold-wall chemical vapor deposition(CVD).During the synthesis,carbon from^(12)C-and^(13)C-methane was deposited on,and dissolved in,a nickel foil at high temperature,and a uniform graphite film was segregated from the nickel surface by cooling the sample to room temperature.Scanning and transmission electron microscopy,micro-Raman spectroscopy,and X-ray diffraction prove the presence of a graphite film.Monolayer graphene films obtained from such isotopically-labeled graphite films by mechanical methods have electron mobility values greater than 5000 cm^(2)·V^(-1)·s^(-1)at low temperatures.Furthermore,such films exhibit the half-integer quantum Hall effect over a wide temperature range from 2 K to 200 K,implying that the graphite grown by this cold-wall CVD approach has a quality as high as highly oriented pyrolytic graphite(HOPG).The results from transport measurements indicate that^(13)C-labeling does not significantly affect the electrical transport properties of graphene.Weiwei Cai Richard D.Piner Yanwu Zhu Xuesong Li Zhenbing Tan Herman Carlo Floresca Changli Yang Li Lu M.J.Kim Rodney S.Ruoff 2009Nano Research2009,2,11:7
4Influence of rare earth Ce on hot deformation behavior of as-cast Mn18Cr18N high nitrogen austenitic stainless steel显示文摘The hot deformation behavior of Mn18Cr18N and Mn18Cr18N+Ce high nitrogen austenitic stainless steels at 1173-1473 K and 0.01-1 s^(-1) were investigated by thermal compression tests.The influence mechanism of Ce on the hot deformation behavior was analyzed by Ce-containing inclusions and segregation of Ce.The results show that after the addition of Ce,large,angular,hard,and brittle inclusions(TiN-Al_(2)O_(3),TiN,and Al_(2)O_(3)) can be modified to fine and dispersed Ce-containing inclusions(Ce-Al-O-S and TiN-Ce-Al-O-S).During the solidification,Ce-containing inclusions can be used as heterogeneous nucleation particles to refine as-cast grains.During the hot deformation,Ce-containing inclusions can pin dislocation movement and grain boundary migration,induce dynamic recrystallization(DRX)nucleation,and avoid the formation and propagation of micro cracks and gaps.In addition,during the solidification,Ce atoms enrich at the front of solid-li-quid interface,resulting in composition supercooling and refining the secondary dendrites.Similarly,during the hot deformation,Ce atoms tend to segregate at the boundaries of DRX grains,inhibiting the growth of grains.Under the synergistic effect of Ce-containing inclusions and Ce segregation,although the hot deformation resistance and hot deformation activation energy are improved,DRX is more likely to occur and the size of DRX grains is significantly refined,and the problem of hot deformation cracking can be alleviated.Finally,the microhardness of the samples was measured.The results show that compared with as-cast samples,the microhardness of hot-deformed samples increases signific-antly,and with the increase of DRX degree,the microhardness decreases continuously.In addition,Ce can affect the microhardness of Mn18Cr18N steel by affecting as-cast and hot deformation microstructures.Yushuo Li Yanwu Dong Zhouhua Jiang Qingfei Tang Shuyang Du Zhiwen Hou 2023International Journal of Minerals,Metallurgy and Materials2023,30,2:4
5Overview and Development of Variable Frequency AC Generators for More Electric Aircraft Generation System显示文摘With the development of more electric aircraft(MEA),higher demands for electrical energy are put forward in generation systems.Compared to constant frequency AC(CFAC)generation systems,the constant speed drive(CSD)is eliminated and integrated starter/generator(SG)can be realized in variable frequency AC(VFAC)generation systems.In this paper,an overview of VFAC generators for safety-critical aircraft applications is presented,with a particular focus on the key features and requirements of candidate generators and the starting control strategies.Wound rotor synchronous machines(WRSMs)are typical generators used in VFAC generation systems so far.Meanwhile,hybrid excitation synchronous machines(HESMs)and cage-type induction machines are promising candidates for VFAC generation systems.The generation operation of WRSM is relatively mature,however,the SG technology of WRSM is still full of challenges.As one of the most important issues,the starting excitation methods of WRSM are summarized.An HESM-based VFAC SG system is proposed and developed in this paper.The experimental results show that the starting mode,transition mode and generating mode of the VFAC SG system are realized.The continuous progress of VFAC generation system makes great contributions to the realization of MEA.Zhuoran Zhang Jincai Li Ye Liu Yanwu Xu Yangguang Yan 2017Chinese Journal of Electrical Engineering2017,3,2:4
6Development and Utilization of Saline Lake Resources and Protection of Ecological Environment in Qaidam Basin in Qinghai Province显示文摘Qaidam basin is an important part of National Key Development Area–Lanzhou-Xining Area,is a key region of resource development in Western Development,is a National Circular Economy Pilot Zone.The focusMENG Wei SHU Jianmin YANG Rongjin LI Yanwu 2014Acta Geologica Sinica(English Edition)2014,88,S1:3
7Identification of Graves’ophthalmology by laser-induced breakdown spectroscopy combined with machine learning method显示文摘Diagnosis of the Graves’ophthalmology remains a significant challenge.We identified between Graves’ophthalmology tissues and healthy controls by using laser-induced breakdown spectroscopy(LIBS)combined with machine learning method.In this work,the paraffin-embedded samples of the Graves’ophthalmology were prepared for LIBS spectra acquisition.The metallic elements(Na,K,Al,Ca),non-metallic element(O)and molecular bands((C-N),(C-O))were selected for diagnosing Graves’ophthalmology.The selected spectral lines were inputted into the supervised classification methods including linear discriminant analysis(LDA),support vector machine(SVM),k-nearest neighbor(ANN),and generalized regression neural network(GRNN),respectively.The results showed that the predicted accuracy rates of LDA,SVM,ANN,GRNN were 76.33%,96.28%,96.56%,and 96.33%,respectively.The sensitivity of four models were 75.89%,93.78%,96.78%,and 96.67%,respectively.The specificity of four models were 76.78%,98.78%,96.33%,and 96.00%,respectively.This demonstrated that LIBS assisted with a nonlinear model can be used to identify Graves’ophthalmopathy with a higher rate of accuracy.The ANN had the best performance by comparing the three nonlinear models.Therefore,LIBS combined with machine learning method can be an effective way to discriminate Graves’ophthalmology.Jingjing LI Feng CHEN Guangqian HUANG Siyu ZHANG Weiliang WANG Yun TANG Yanwu CHU Jian YAO Lianbo GUO Fagang JIANG 2021Frontiers of Optoelectronics2021,14,3:3
8Structural engineering of cathodes for improved Zn-ion batteries显示文摘Aqueous zinc-ion batteries(ZIBs) are attracting considerable attention because of their low cost,high safety and abundant anode material resources.However,the major challenge faced by aqueous ZIBs is the lack of stable and high capacity cathode materials due to their complicated reaction mechanism and slow Zn-ion transport kinetics.This study reports a unique 3 D ’flower-like’ zinc cobaltite(ZnCo_(2)O_(4-x)) with enriched oxygen vacancies as a new cathode material for aqueous ZIBs.Computational calculations reveal that the presence of oxygen vacancies significantly enhances the electronic conductivity and accelerates Zn^(2+) diffusion by providing enlarged channels.The as-fabricated batteries present an impressive specific capacity of 148.3 mAh g^(-1) at the current density of 0.05 A g^(-1),high energy(2.8 Wh kg^(-1)) and power densities(27.2 W kg^(-1)) based on the whole device,which outperform most of the reported aqueous ZIBs.Moreover,a flexible solid-state pouch cell was demonstrated,which delivers an extremely stable capacity under bending states.This work demonstrates that the performance of Zn-ion storage can be effectively enhanced by tailoring the atomic structure of cathode materials,guiding the development of low-cost and eco-friendly energy storage materials.Jiajia Huang Yuying Li Ruikuan Xie Jianwei Li Zhihong Tian Guoliang Chai Yanwu Zhang Feili Lai Guanjie He Chuntai Liu Tianxi Liu Dan J.L.Brett 2021Journal of Energy Chemistry2021,30,7:3
9Ranking with decision tree显示文摘Fen Xia Wensheng Zhang Fuxin Li Yanwu Yang 2008Knowledge and Information Systems2008,,3:1
10Correlation of the cyclin A expression level with porcine circovirus type 2 propagation efficiency显示文摘Qinghai Tang Shengbin Li Hui Zhang Yanwu Wei Hongli Wu Jianbo Liu Yiping Wang Dan Liu Zhihui Zhang Changming Liu 2013Archives of Virology2013,,12:1
11On regularity of G-rnorphic rings显示文摘LI Yanwu CHU Maoquan 2007Journal of Anhui Normal University(Natural Science)2007,30,5:1
12Observation of the nighttime nitrate radical in Hefei, China显示文摘夜间硝酸盐基(NO3 ) 的观察被使用长路径执行微分光吸收光谱学(LP-DOAS ) 在 Hefei 的郊区,中国。NO3 和支持的参数的时间系列同时被测量一个星期(7 年 5 月 31 日 2006 年 6 月) 。结果显示 NO3 的平均集中是 15.6 pptv 与一 96 s 的平均寿命,而, NO3 生产率从 8 × 105/(cm3 · s ) 变化了到 2.98 × 107/(cm3 · s ) 。而且,计算 N2O5concentration 在 380 点平均 pptv。数据的分析显示直接水池可能在这个运动期间正在统治 NO3 损失进程。结果与在边界层的另外的运动相比。LI Suwen LIU Wenqing XIE Pinua LI Ang QIN Min PENG Fumin ZHU Yanwu 2008Journal of Environmental Sciences2008,20,1:1
13Behavior and functional modeling methods of doubly salient electromagnetic generators for aircraft electrical power system applications显示文摘The Doubly Salient Electromagnetic Generator(DSEG) is a promising candidate in aircraft generator application due to the simplicity, robustness and reliability. However, the field windings and the armature windings are strongly coupled, which makes the inductance characteristics non-linear and too complex to model. The complex model with low precision also leads to difficulties in modeling and analysis of the entire aircraft Electrical Power System(EPS). A behavior level modeling method based on modified inductance Support Vector Machine(SVM) is proposed. The Finite Element Analysis(FEA) inductance data are modified based on the experiment results to improve the precision. A functional level modeling method based on input–output characteristics SVM is also proposed. The two modeling methods are applied to a 9 kW DSEG prototype. The steady state and transient process precision of the proposed methods are proved by comparing with the experiment results. Meanwhile, the modeling time consumption, the application time consumption and the calculation resource demand are compared. The DSEG behavior and functional modeling methods provide precious results with high efficiency, which accelerates theoretical analysis and expands the application foreground of the DSEG in the aircraft EPS.Yanwu XU Zhuoran ZHANG Li YU Yuke SHI 2019Chinese Journal of Aeronautics2019,32,2:1
14Three Dimen- sional Temperature Field Simulation for the Rotor of an Synchronous Motor显示文摘Yanwu Wang Chunli Fan Li Yang 2010European Journal of Physics2010,31,4:1
15Transfer of large-area graphene films for high-performance transparent conductive electrodes显示文摘Xuesong Li Yanwu Zhu Weiwei Cai 2009Nano letters2009,9,12:1
16Research on security assessment model of water supply system based on Leakage Control显示文摘LI Hongwei LI Yanjing WEN Yanwu 0,,11:1
17The standardized design and application guidelines: A primary-oriented artificial intelligence screening system of the lesion sign in the macular region based on fundus color photography显示文摘With the popularity and development of artificial intelligence(AI),disease screening systems based on AI algorithms are gradually emerging in the medical field.Such systems can be used for primary screening of diseases to relieve the pressure on primary health care.In recent years,AI algorithms have demonstrated good performance in the analysis and identification of lesion signs in the macular region of fundus color photography,and a screening system for fundus lesion signs applicable to primary screening is bound to emerge in the future.Therefore,to standardize the design and clinical application of macular region lesion sign screening systems based on AI algorithms,the Ocular Fundus Diseases Group of Chinese Ophthalmological Society,in collaboration with relevant experts,developed this guideline after investigating issues,discussing production evidence,and holding guideline workshops.It aimed to establish uniform standards for the definition of the macular region and lesion signs,AI adoption scenarios,algorithm model construction,dataset establishment and labeling,architecture and function design,and image data acquisition for the screening system to guide the implementation of the screening work.Ocular Fundus Diseases Group of Chinese Ophthalmological Society Expert Group for Artificial Intelligence Research,Development,and Application Xiaoxin Li Ming Zhang Yanwu Xu 2023Intelligent Medicine2023,3,3:0
18Handwashing quality assessment via deep learning:a modelling study for monitoring compliance and standards in hospitals and communities显示文摘Background Hand hygiene can be a simple,inexpensive,and effective method for preventing the spread of infectious diseases.However,a reliable and consistent method for monitoring adherence to the guidelines within and outside healthcare settings is challenging.The aim of this study was to provide an approach for monitoring handwashing compliance and quality in hospitals and communities.Methods We proposed a deep learning algorithm comprising three-dimensional convolutional neural networks(3D CNNs)and used 230 standard handwashing videos recorded by healthcare professionals in the hospital or at home for training and internal validation.An assessment scheme with a probability smoothing method was also proposed to optimize the neural network’s output to identify the handwashing steps,measure the exact duration,and grade the standard level of recognized steps.Twenty-two videos by healthcare professionals in another hospital and 28 videos recorded by civilians in the community were used for external validation.Results Using a deep learning algorithm and an assessment scheme,combined with a probability smoothing method,each handwashing step was recognized(ACC ranged from 90.64%to 98.87%in the hospital and from 87.39%to 96.71%in the community).An assessment scheme measured each step’s exact duration,and the intraclass correlation coefficients were 0.98(95%CI:0.97-0.98)and 0.91(95%CI:0.88-0.93)for the total video duration in the hospital and community,respectively.Furthermore,the system assessed the quality of handwashing,similar to the expert panel(kappa=0.79 in the hospital;kappa=0.65 in the community).Conclusions This work developed an algorithm to directly assess handwashing compliance and quality from videos,which is promising for application in healthcare settings and communities to reduce pathogen transmis-sion.Ting Wang Jun Xia Tianyi Wu Huanqi Ni Erping Long Ji-Peng Olivia Li Lanqin Zhao Ruoxi Chen Ruixin Wang Yanwu Xu Kai Huang Haotian Lin 2022Intelligent Medicine2022,2,3:0
19Empirical Analysis of Determinant Factors of the Corporate Performance of Life Insurance Companies in China显示文摘The life insurance industry in China still stays at a primary stage of development. It is characterized by small size, low penetration, and low density. Nevertheless, China’s large population, together with the emerging middle class, and the continuously improving social and economic environment, promise the life insurance industry a bright future. The government’s limited pension reserves cannot effectively deal with the aging problem, implying that commercial insurance companies are bound to play a more critical role in alleviating the aging problem. In 2014, Chinese government issued a series of favorable policies. Life insurance companies are now allowed to invest a certain proportion of premium in high risk issues and set the return on investment (ROI) of saving insurance products higher than 2.5%. Changes in external factors and policies prompt life insurance companies to change their operation mode so that they can meet the market demand. This paper empirically analyzes operational factors (such as structure of distribution channels, structure of products, human resource, market power, etc.) that affect the corporate performance of Chinese life insurance companies. The paper aims to help life insurance companies choose a proper distribution channel, focus marketing expenses and R&D on the right product, set the scale and the salesman team at a rational size, and adjust the compensation ratio to a rational level. The data are gathered from 36 high-ranked Chinese life insurance companies from 2010 to 2014. The panel data set is analyzed via fixed effect model and panel threshold model. To avoid spurious regression, a series of preliminary tests are conducted. The results show that percentage of revenue from bancassurance channel, percentage of revenue from specialized insurance agencies, percentage of revenue from saving product, percentage of revenue from group product, size of insurers, market share of insurers, and solvency rate all have negative effect on the corporate performance of life insurance companies. If an insurer were a subsidiary of a bank, its percentage of revenue from bancassureance would have a positive effect on its corporate performance. The paper contributes to existing literature on how particular distribution channels and products of Chines life insurance companies affect their corporate performance.Yanwu Li 2019经济管理学刊(中英文版)2019,8,1:0
20PHB介导的HIRA复合物调控人胚胎干细胞的表观--代谢环路显示文摘文章简介染色质地貌和细胞代谢对细胞命运决定有着重要的作用,但人们对它们之间的相互作用却了解甚少。课题组运用基因组范围的si RNA筛选,发现PHB对于维持人胚胎干细胞的自我更新具有重要的作用。Huanhuan Li Ping Lai Jinping Jia Yawei Song Qing Xia Kaimeng Huang Na He Wangfang Ping Jiayu Chen Zhongzhou Yang Jiao Li Mingze Yao Xiaotao Dong Jicheng Zhao Chunhui Hou Miguel A.Esteban Shaorong Gao Duanqing Pei Andrew P.Hutchins 姚红杰 Zhexin Zhu Chunliang Li Yanwu Zeng Jianyi Ding Zepeng Qu Junjie Gu Laixiang Ge Fan Tang Xin Huang Chenlin Zhou Ping Wang Deyou Zheng 金颖 2018科学新闻2018,0,4:0
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