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Dimensionality reduction model based on integer planning for the analysis of key indicators affecting life expectancy
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作者 Wei Cui zhiqiang xu Ren Mu 《Journal of Data and Information Science》 CSCD 2023年第4期102-124,共23页
Purpose:Exploring a dimensionality reduction model that can adeptly eliminate outliers and select the appropriate number of clusters is of profound theoretical and practical importance.Additionally,the interpretabilit... Purpose:Exploring a dimensionality reduction model that can adeptly eliminate outliers and select the appropriate number of clusters is of profound theoretical and practical importance.Additionally,the interpretability of these models presents a persistent challenge.Design/methodology/approach:This paper proposes two innovative dimensionality reduction models based on integer programming(DRMBIP).These models assess compactness through the correlation of each indicator with its class center,while separation is evaluated by the correlation between different class centers.In contrast to DRMBIP-p,the DRMBIP-v considers the threshold parameter as a variable aiming to optimally balances both compactness and separation.Findings:This study,getting data from the Global Health Observatory(GHO),investigates 141 indicators that influence life expectancy.The findings reveal that DRMBIP-p effectively reduces the dimensionality of data,ensuring compactness.It also maintains compatibility with other models.Additionally,DRMBIP-v finds the optimal result,showing exceptional separation.Visualization of the results reveals that all classes have a high compactness.Research limitations:The DRMBIP-p requires the input of the correlation threshold parameter,which plays a pivotal role in the effectiveness of the final dimensionality reduction results.In the DRMBIP-v,modifying the threshold parameter to variable potentially emphasizes either separation or compactness.This necessitates an artificial adjustment to the overflow component within the objective function.Practical implications:The DRMBIP presented in this paper is adept at uncovering the primary geometric structures within high-dimensional indicators.Validated by life expectancy data,this paper demonstrates potential to assist data miners with the reduction of data dimensions.Originality/value:To our knowledge,this is the first time that integer programming has been used to build a dimensionality reduction model with indicator filtering.It not only has applications in life expectancy,but also has obvious advantages in data mining work that requires precise class centers. 展开更多
关键词 Integer programming Multidimensional data Dimensionality reduction Life expectancy
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Strategies for Improving the Effectiveness of Professional Practice for Full-Time Professional Master Degree Postgraduate in Mineral Processing Engineering
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作者 Jiushuai Deng Juan Hu +3 位作者 zhiqiang xu Weidong Wang Zhongyi Bai Tingting Hu 《Journal of Contemporary Educational Research》 2023年第1期27-32,共6页
In order to gain practical experience and hands-on skills,full-time professional master degree postgraduate in mineral processing engineering should engage in professional practices.Nonetheless,a series of problems,in... In order to gain practical experience and hands-on skills,full-time professional master degree postgraduate in mineral processing engineering should engage in professional practices.Nonetheless,a series of problems,including insufficient time for practice,low management level,inadequate implementation of the double-supervisor system,and poor results of professional practice,has reduced the effectiveness of professional practice.In view of the aforementioned problems and the characteristics of the discipline,this paper proposes several strategies for improving the effectiveness of professional practice for postgraduates in mineral processing engineering. 展开更多
关键词 Mineral processing engineering FULL-TIME Application-oriented Master’s degree Professional practice
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Light-absorbing impurities on Keqikaer Glacier in western Tien Shan: concentrations and potential impact on albedo reduction 被引量:4
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作者 YuLan Zhang ShiChang Kang +11 位作者 Min xu Michael Sprenger TanGuang Gao ZhiYuan Cong ChaoLiu Li JunMing Guo zhiqiang xu Yang Li Gang Li XiaoFei Li YaJun Liu HaiDong Han 《Research in Cold and Arid Regions》 CSCD 2017年第2期97-111,共15页
Light-absorbing impurities on glaciers are important factors that influence glacial surface albedo and accelerate glacier melt. In this study, the quantity of light-absorbing impurities on Keqikaer Glacier in western ... Light-absorbing impurities on glaciers are important factors that influence glacial surface albedo and accelerate glacier melt. In this study, the quantity of light-absorbing impurities on Keqikaer Glacier in western Tien Shan, Central Asia, was measured. We found that the average concentrations of black carbon was 2,180 ng/g, with a range from 250 ng/g to more than 10,000 ng/g. The average concentrations of organic carbon and mineral dust were 1,738 ng/g and 194 μg/g, respectively. Based on simulations performed with the Snow Ice Aerosol Radiative model simulations, black carbon and dust are responsible for approximately 64% and 9%, respectively, of the albedo reduction, and are associated with instantaneous radiative forcing of 323.18 W/m2(ranging from 142.16 to 619.25 W/m2) and 24.05 W/m2(ranging from 0.15 to69.77 W/m2), respectively. For different scenarios, the albedo and radiative forcing effect of black carbon is considerably greater than that of dust. The estimated radiative forcing at Keqikaer Glacier is higher than most similar values estimated by previous studies on the Tibetan Plateau, perhaps as a result of black carbon enrichment by melt scavenging. Light-absorbing impurities deposited on Keqikaer Glacier appear to mainly originate from central Asia, Siberia, western China(including the Taklimakan Desert) and parts of South Asia in summer, and from the Middle East and Central Asia in winter.A footprint analysis indicates that a large fraction(>60%) of the black carbon contributions on Keqikaer Glacier comes from anthropogenic sources. These results provide a scientific basis for regional mitigation efforts to reduce black carbon. 展开更多
关键词 light-absorbing IMPURITIES black carbon mineral dust GLACIER SNOW ALBEDO Tien Shan
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The characteristics of shear wave splitting in the source region of the April 20,2013 Lushan earthquake 被引量:2
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作者 Sha Liu Jiansi Yang +3 位作者 Baofeng Tian Yu Zheng xudong Jiang zhiqiang xu 《Earthquake Science》 2013年第3期223-228,共6页
Using seismic data of the aftershocks sequence of the April 20,2013 Lushan earthquake recorded by seismic temporary and permanent stations in the source region,with the visual inspection of particle motion diagrams,th... Using seismic data of the aftershocks sequence of the April 20,2013 Lushan earthquake recorded by seismic temporary and permanent stations in the source region,with the visual inspection of particle motion diagrams,this paper preliminarily contains the polarization directions of fast shear wave and the time-delays of split shear waves at every station,and analyzes the crustal anisotropic characteristics in the source region.In the study area,the polarization directions at stations BAX,TQU,L132,L133,L134,and L135 are northeast,which is consistent with the strike of Dachuan–Shuangshi fault.There are two polarization directions at MDS and L131,which are northeast and southeast.The scatter of polarization directions suggests the complex stress field around these two stations where two faults intersect.For the normalized time-delays at every station,the range is1.02–8.64 ms/km.The largest time-delay is from L134which is closest to the mainshock,and the smallest one is from L133.The variations in time-delays show the decreasing at stations BAX,L134,and L135 because of the stress–relaxation after earthquake. 展开更多
关键词 横波分裂 震源区 庐山 时间延迟 偏振方向 地震数据 断层走向 余震序列
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Difference of planktonic ciliate communities of the tropical West Pacific, the Bering Sea and the Arctic Ocean 被引量:2
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作者 Chaofeng Wang Haibo Li +8 位作者 zhiqiang xu Shan Zheng Qiang Hao Yi Dong Li Zhao Wuchang Zhang Yuan Zhao Gérald Grégori Tian Xiao 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2020年第4期9-17,共9页
Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three s... Ciliates are important components in planktonic food webs,but our understanding of their community structures in different oceanic water masses is limited.We report pelagic ciliate community characteristics in three seas:the tropical West Pacific,the Bering Sea and the Arctic Ocean.Planktonic ciliate abundance had"bimodal-peak","surface-peak"and"DCM(deep chlorophyll a maximum layer)-peak"vertical distribution patterns in the tropical West Pacific,the Bering Sea and the Arctic Ocean,respectively.The abundance proportion of tintinnid to total ciliate in the Bering Sea(42.6%)was higher than both the tropical West Pacific(7.8%)and the Arctic Ocean(2.0%).The abundance proportion of small aloricate ciliates(10–20μm size-fraction)in the tropical West Pacific was highest in these three seas.The Arctic Ocean had higher abundance proportion of tintinnids in larger LOD(lorica oral diameter)size-class.Proportion of redundant species increased from the Arctic Ocean to the tropical West Pacific.Our result provided useful data to further understand ecology roles of planktonic ciliates in different marine habitats. 展开更多
关键词 planktonic ciliates vertical distribution community structure tropical West Pacific Bering Sea Arctic Ocean
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Research Progress on the Development and Application of New Natural Tobacco Humectants 被引量:2
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作者 Xiaojing MA Xinge LIU +3 位作者 zhiqiang xu Yingbo xu Huai WANG Risheng YAO 《Agricultural Science & Technology》 CAS 2016年第5期1261-1267,共7页
The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages a... The research progress on the development and application of new natural tobacco humectants was reviewed in the paper.Plants,animals and microbes contain special moisturizing substances,showing distinctive advantages and outstanding effects in respect of the tobacco moisture content maintaining and cigarette suction comfort promoting.The development necessity,major types,functional mechanism and influence on cigarette quality of new natural tobacco humectants development were compared and elaborated.Additionally,the prospect of new natural tobacco humectants development and application was forecasted. 展开更多
关键词 保湿剂 烟草 天然 应用 开发 水分保持 微生物
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Longitudinal genetic analysis of growth-related traits in red swamp crayfish Procambarus clarkii (Girard)
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作者 Hui WANG Yi ZHANG +3 位作者 Guoliang CHANG Nan WU zhiqiang xu Jianqing TANG 《Journal of Oceanology and Limnology》 SCIE CAS CSCD 2022年第2期775-785,共11页
The red swamp crayfish,Procambarus clarkii,is an economically important species especially in China.Their exoskeleton places serious constraints on growth and culture management.Their growth is achieved through interm... The red swamp crayfish,Procambarus clarkii,is an economically important species especially in China.Their exoskeleton places serious constraints on growth and culture management.Their growth is achieved through intermittent molting/ecdysis.The longitudinal genetic dynamics for growth-related traits at different ecdysial points in P.clarkii has been unclear to date.In this study,conditional genetic analysis was carried out for growth-related traits(body weight,body length,chela length,and cephalothorax length)based upon a mixed genetic model with conditional additive,dominance,and genotype by environment effects in P.clarkii.A complete diallel cross was made among three geographic populations of P.clarkii for the genetic mating design.Results of the conditional genetic analysis showed that from 4 th molt to 9 th molt the conditional additive variations were increased significantly whereas the conditional non-additive genetic variations(dominance and genotype by environment interaction)were decreased significantly for these growth-related traits.This indicated that lots of new expression of additive effect genes for body weight,body length,chela length,and cephalothorax length occurred during ontogeny,and environment played a signifi cant role in the expression of genes affecting these growth-related traits.Growth of the four traits was mainly affected by non-additive genetic effects in early developmental stage(prior to 4 th molt).The cumulative conditional additive variation for the growth-related traits from 4 th molt to 9 th molt accounted for a large majority of the total conditional additive variations from 2 nd molt to 9 th molt,indicating that this period was very important for the growth of this species.Using the conditional analysis method,dynamics of growth-related traits during an important ontogenetic phase of red swamp crayfish was uncovered.Our results provide valuable insights into refining production of this species. 展开更多
关键词 mating design conditional genetic analysis model Procambarus clarkii genetic effect conditional variance component longitudinal genetic analysis
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Effect of Data Augmentation of Renal Lesion Image by Nine-layer Convolutional Neural Network in Kidney CT
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作者 Liying Wang zhiqiang xu Shuihua Wang 《Computer Modeling in Engineering & Sciences》 SCIE EI 2020年第9期1001-1015,共15页
Artificial Intelligence(AI)becomes one hotspot in the field of the medical images analysis and provides rather promising solution.Although some research has been explored in smart diagnosis for the common diseases of ... Artificial Intelligence(AI)becomes one hotspot in the field of the medical images analysis and provides rather promising solution.Although some research has been explored in smart diagnosis for the common diseases of urinary system,some problems remain unsolved completely A nine-layer Convolutional Neural Network(CNN)is proposed in this paper to classify the renal Computed Tomography(CT)images.Four group of comparative experiments prove the structure of this CNN is optimal and can achieve good performance with average accuracy about 92.07±1.67%.Although our renal CT data is not very large,we do augment the training data by affine,translating,rotating and scaling geometric transformation and gamma,noise transformation in color space.Experimental results validate the Data Augmentation(DA)on training data can improve the performance of our proposed CNN compared to without DA with the average accuracy about 0.85%.This proposed algorithm gives a promising solution to help clinical doctors automatically recognize the abnormal images faster than manual judgment and more accurately than previous methods. 展开更多
关键词 Artificial intelligence convolutional neural network data augmentation renal lesion computed tomography image
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Recovery of photoacoustic images based on accurate ultrasound positioning
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作者 Yinhao Pan Ningbo Chen +3 位作者 Liangjian Liu Chengbo Liu zhiqiang xu Jianhui Zhang 《Visual Computing for Industry,Biomedicine,and Art》 EI 2021年第1期63-69,共7页
Photoacoustic microscopy is an in vivo imaging technology based on the photoacoustic effect.It is widely used in various biomedical studies because it can provide high-resolution images while being label-free,safe,and... Photoacoustic microscopy is an in vivo imaging technology based on the photoacoustic effect.It is widely used in various biomedical studies because it can provide high-resolution images while being label-free,safe,and harmless to biological tissue.Polygon-scanning is an effective scanning method in photoacoustic microscopy that can realize fast imaging of biological tissue with a large field of view.However,in polygon-scanning,fluctuations of the rotating motor speed and the geometric error of the rotating mirror cause image distortions,which seriously affect the photoacoustic-microscopy imaging quality.To improve the image quality of photoacoustic microscopy using polygon-scanning,an image correction method is proposed based on accurate ultrasound positioning.In this method,the photoacoustic and ultrasound imaging data of the sample are simultaneously obtained,and the angle information of each mirror used in the polygon-scanning is extracted from the ultrasonic data to correct the photoacoustic images.Experimental results show that the proposed method can significantly reduce image distortions in photoacoustic microscopy,with the image dislocation offset decreasing from 24.774 to 10.365μm. 展开更多
关键词 Photoacoustic microscopy Polygon-scanning Image correction Ultrasound positioning
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Optimal Motion Planning of the Space Manipulator for Minimum Reaction Torque to Satellite
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作者 zhiqiang xu Xiangxin Zeng +1 位作者 Jinghui Li Zhaoyan Jia 《Journal of Harbin Institute of Technology(New Series)》 CAS 2022年第2期81-91,共11页
For the problem of free⁃floating space robot(FFSR)that the motion of manipulator will cause a large disturbance to the attitude of satellite,a path planning method based on hp⁃adaptive Gauss pseudospectral method(hp⁃A... For the problem of free⁃floating space robot(FFSR)that the motion of manipulator will cause a large disturbance to the attitude of satellite,a path planning method based on hp⁃adaptive Gauss pseudospectral method(hp⁃AGPM)is proposed in this paper.In this method,the minimum reaction torque acting on satellite is taken as the objective function,and the number of segments and the order of polynomial in each segment are determined adaptively to improve the accuracy and the efficiency of the solution.At the same time,the theoretical convergence of the designed method is innovatively proved to ensure that the solution of the discretized nonlinear programming(NLP)problem is the optimal solution to the original optimal problem.The simulation results of a planar two degree⁃of⁃freedom(2⁃DOF)space manipulator show that the proposed path planning method is more effective than the resolved acceleration control(RAC)method and the control variable parameterization(CVP)method,and is better than other pseudospectral methods both in computation speed and the number of collocation points. 展开更多
关键词 free⁃floating space robot hp-adaptive Gauss pseudospectral method path planning nonlinear programming
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The equivalent model of controller in synchronous frame to stationary frame 被引量:1
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作者 Yichao Wang Lai Huang +5 位作者 Yijia Cao Xintao Xie Zhongwei Chen Zhenfeng Xiao Ming Wen zhiqiang xu 《Global Energy Interconnection》 2018年第2期122-129,共8页
The system controlled in synchronous frame is commonly used. However, it is a problem how to transform the controller in synchronous frame to stationary frame. This paper deduces the stationary frame equivalent model ... The system controlled in synchronous frame is commonly used. However, it is a problem how to transform the controller in synchronous frame to stationary frame. This paper deduces the stationary frame equivalent model of arbitrarily controller in synchronous frame. The equivalent model can reflect the control performance of the input signal at different frequency accurately. The unified frequency-domain model of the overall system can be established using the equivalent model, and the guidance for frequency analysis and stability analysis can be provided. Theoretical derivation and simulation results verify the correctness and generality of the equivalent model. 展开更多
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GRAPH SPARSIFICATION BY UNIVERSAL GREEDY ALGORITHMS
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作者 Ming-Jun Lai Jiaxin Xie zhiqiang xu 《Journal of Computational Mathematics》 SCIE CSCD 2023年第4期741-770,共30页
Graph sparsification is to approximate an arbitrary graph by a sparse graph and is useful in many applications,such as simplification of social networks,least squares problems,and numerical solution of symmetric posit... Graph sparsification is to approximate an arbitrary graph by a sparse graph and is useful in many applications,such as simplification of social networks,least squares problems,and numerical solution of symmetric positive definite linear systems.In this paper,inspired by the well-known sparse signal recovery algorithm called orthogonal matching pursuit(OMP),we introduce a deterministic,greedy edge selection algorithm,which is called the universal greedy approach(UGA)for the graph sparsification problem.For a general spectral sparsification problem,e.g.,the positive subset selection problem from a set of m vectors in R n,we propose a nonnegative UGA algorithm which needs O(mn^(2)+n^(3)/ϵ^(2))time to find a 1+ϵ/β/1-ϵ/β-spectral sparsifier with positive coefficients with sparsity at most[n/ϵ^(2)],where β is the ratio between the smallest length and largest length of the vectors.The convergence of the nonnegative UGA algorithm is established.For the graph sparsification problem,another UGA algorithm is proposed which can output a 1+O(ϵ)/1-O(ϵ)-spectral sparsifier with[n/ϵ^(2)]edges in O(m+n^(2)/ϵ^(2))time from a graph with m edges and n vertices under some mild assumptions.This is a linear time algorithm in terms of the number of edges that the community of graph sparsification is looking for.The best result in the literature to the knowledge of the authors is the existence of a deterministic algorithm which is almost linear,i.e.O(m^(1+o(1)))for some o(1)=O((log log(m))^(2/3)/log^(1/3)(m)).Finally,extensive experimental results,including applications to graph clustering and least squares regression,show the effectiveness of proposed approaches. 展开更多
关键词 Spectral sparsification Subset selection Greedy algorithms Graph clustering Linear sketching
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Sucrose enhances the chromogenic ability of Staphylococcus xylosus by improving nitric oxide synthase activity
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作者 徐志强 郑文滨 +3 位作者 赵尚 陈勇 杨庆利 朱英莲 《Food Quality and Safety》 SCIE CSCD 2023年第1期167-177,共11页
In this paper,the effect of different concentrations of sucrose stress on color formation of the Staphylococcus xylosus was investigated.The results showed that the highest a*value and the best coloring effect similar... In this paper,the effect of different concentrations of sucrose stress on color formation of the Staphylococcus xylosus was investigated.The results showed that the highest a*value and the best coloring effect similar to those of nitrite were observed after the addition of 0.05 g/mL sucrose to stress the S.xylosus.UV-Vis and electron spin resonance spectra analysis showed that production of coloring product Mb-NO was significantly enhanced after 0.05 g/mL sucrose stress.The growth curve,reactive oxygen content,cell cycle,nitric oxide synthase(NOS)activity,zeta potential,cell size,and protein composition of S.xylosus were investigated to reveal the mechanism of sucrose stress to enhance the coloring effect of the strain.The result showed that sucrose inhibited the growth of S.xylosus,which changed the physiological state by activating the oxidative stress response.The stress altered the rate of intracellular metabolism of S.xylosus by delaying the cell cycle and increasing cell surface zeta potential and cell particle size.These changes altered the protein composition of the cells and significantly enhanced the activity of intracellular NOS,which could improve the chromogenic ability of S.xylosus.This study will provide theoretical support for sucrose stress on S.xylosus to enhance its coloring effect,and sucrose stress for S.xylosus might be a promising biological alternative to nitrite in meat products. 展开更多
关键词 Staphylococcus xylosus NITRITE sucrose stress color formation nitric oxide synthase
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Functional Cure of Chronic Hepatitis B with Antiviral Treatment in Children having High-level Viremia and Normal or Mildly Elevated Serum Aminotransferase
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作者 Jing Li Peiyao Fan +11 位作者 zhiqiang xu Yi Dong Fuchuan Wang Weiguo Hong Jinfang Zhao Yinjie Gao Jianguo Yan Lili Cao Chao Zhang Shishu Zhu Fu-Sheng Wang Min Zhang 《Journal of Clinical and Translational Hepatology》 SCIE 2023年第5期1011-1022,共12页
Background and Aims:There is a lack of data supporting the notion that antiviral treatments can beneft children with chronic hepatitis B(CHB)having high viremia and normal or mildly elevated serum alanine aminotransfe... Background and Aims:There is a lack of data supporting the notion that antiviral treatments can beneft children with chronic hepatitis B(CHB)having high viremia and normal or mildly elevated serum alanine aminotransferase(ALT)levels.We aimed t analyze the efficacy of antiviral treatments in children with CHB and explore the factors associated with functional cure.Methods:Forty-eight children with CHB having high viremia and normal or mildly elevated serum ALT levels were screened in this real-world study.Thirty-two children received either interferon-alpha(IFN-α)monother-apy,IFN-a therapy with a nucleoside analog(NA)add-on,or IFN-α and NA combination therapy.The 16 children in the control group did not receive antiviral treatment.All 48 chil-dren were available for follow-up assessments for the entire 36-month study period.We identified a functional cure with respect to hepatitis B virus(HBV)DNA loss,loss/seroconver-sion of circulating hepatitis B e antigen(HBeAg),and loss of hepatitis B surface antigen(HBsAg)with or without serocon-version.Cox regression analysis was employed to evaluate the factors that may have influenced the functional cure.Re-sults:After 36 months,the cumulative functional cure rate was 56.25%(18/32)in the treated group and 0%(0/16)in the control group(p<0.001).In the treated group,the serum HBV DNA levels declined rapidly at the end of a 6-month visit and the cured children achieved a loss rate of 100%(18/18)within 16 months of beginning treatment,compared with 64.29%(9/14)of the uncured children(p<0.001).The rates of HBeAg seroconversion were significantly higher among the cured children than among the uncured children(p<0.001).All 16 children in the control group maintained high levels of serum HBV DNA and were positive for both serum HBeAg and HBsAg during the entire 36 months of the study period.Func tional cure was associated with younger ages(1-6 vs.7-14 years,p=0.013),CD8^(+)T lymphocyte counts(p=0.013),and B lymphocyte counts(p=0.003).No serious adverse events were observed.Conclusions:Antiviral treatment achieved a functional cure of CHB in a high proportion of children having high-level viremia and normal or mildly elevated ALT levels.Younger age and high peripheral lymphocyte counts were as sociated with this functional cure. 展开更多
关键词 Child HBV Chronic hepatitis B Antiviral therapy Functional cure
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低、中、高度近视患者行SMILE的角膜切削精确性研究 被引量:12
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作者 周海涛 胡中立 +6 位作者 刘巧莉 魏巧慧 徐杨扬 林蒙 许志强 胡亮 瞿佳 《中华眼视光学与视觉科学杂志》 CAS CSCD 2018年第7期414-419,共6页
目的研究不同近视程度患者飞秒激光小切口基质透镜取出术(SMILE)后中央角膜切削误差及其变化趋势,探讨不同近视程度对切削误差的影响.方法:回顾性病例对照研究.选取2017 年1-8 月于温州医科大学附属眼视光医院行SMILE的近视患者61 例... 目的研究不同近视程度患者飞秒激光小切口基质透镜取出术(SMILE)后中央角膜切削误差及其变化趋势,探讨不同近视程度对切削误差的影响.方法:回顾性病例对照研究.选取2017 年1-8 月于温州医科大学附属眼视光医院行SMILE的近视患者61 例(120 眼),将其按术前屈光度分为低度(24眼,-0.50 D≤低度近视≤-3.00 D)、中度(54眼,-3.00 D 〈中度近视≤-6.00 D)以及高度(42眼,高度近视〉 -6.00 D)近视组.于术前、术后1 个月、3 个月使用Sirius眼前节分析系统测量中央角膜厚度(CCT)并计算切削误差及中央角膜切削偏差率,其中切削误差定义为中央角膜实际切削厚度(A-CCT)与预测切削厚度(P-CCT)的差值(△CCT),中央角膜切削偏差率定义为△CCT 与P-CCT的比值.采用配对t检验、单因素方差分析、Kruskal-Wallis H检验以及Pearson相关分析对数据进行分析.结果:各组患者中央角膜实际切削厚度均小于预测切削厚度;术后1 个月和3 个月各组间△CCT差异有统计学意义(F=21.047、35.100,均P 〈 0.001);各组间中央角膜切削偏差率差异无统计学意义.在末次检查时,其中低、中、高度近视组△CCT分别为(-8.9±5.0)μm、(-15.6±6.2)μm、(-21.4±5.9)μm,3 组A-CCT与P-CCT差异均有统计学意义(t =8.67、18.50、23.65,P 〈 0.001).术后切削误差与术前屈光度、切削直径呈正相关(r =0.649、0.384,均P 〈 0.001),与术前CCT呈负相关(r=-0.219,P=0.016).结论:各近视组A-CCT均小于P-CCT;不同近视患者SMILE手术后中央角膜切削误差随着近视程度的增大而增大,但各组间中央角膜切削偏差率保持一致. 展开更多
关键词 飞秒激光小切口基质透镜取出术 中央角膜切削误差 近视 切削偏差率 精确性
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Recent advances in formaldehyde-responsive fluorescent probes 被引量:10
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作者 zhiqiang xu Jianhua Chen +3 位作者 Lin-Li Hu Ying Tan Sheng-Hua Liu Jun Yin 《Chinese Chemical Letters》 SCIE CAS CSCD 2017年第10期1935-1942,共8页
Formaldehyde, as one of the simplest reactive carbonyl species(RCS), is regarded as a potential carcinogen and a sick house syndrome gas. Recent studies have shown that abnormally high levels of formaldehyde may resul... Formaldehyde, as one of the simplest reactive carbonyl species(RCS), is regarded as a potential carcinogen and a sick house syndrome gas. Recent studies have shown that abnormally high levels of formaldehyde may result in cognitive decline and spatial memory deficits, asthmatic symptoms,Alzheimer's disease, and cancer. Due to the harmfulness of high levels of formaldehyde in nature and humans, it is of great significance to further elucidate the roles and functions of formaldehyde by a noninvasive detection approach. Fluorescence imaging has become a powerful and popular tool in monitoring bio-species owing to their high sensitivity and selectivity, excellent spatiotemporal resolution and non-invasion nature. Therefore, fluorescent probes are widely applied to track and detect formaldehyde in vitro and in vivo which have attracted more and more interest recently. This review focuses on various strategies to design the fluorescent probes for detecting formaldehyde based on different recognition groups. 展开更多
关键词 FORMALDEHYDE Fluorescent probes Bioimaging application Sensing mechanism
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Impact time control using biased proportional navigation for missiles with varying velocity 被引量:6
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作者 Guoxin SUN Qiuqiu WEN +1 位作者 zhiqiang xu Qunli XIA 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2020年第3期956-964,共9页
A feasible guidance scheme with impact time constraint is proposed for attacking a stationary target by missiles with time-varying velocity.The main idea is to replace the constant velocity with the future mean veloci... A feasible guidance scheme with impact time constraint is proposed for attacking a stationary target by missiles with time-varying velocity.The main idea is to replace the constant velocity with the future mean velocity;therefore, the existing time-to-go estimation algorithm of the proportional navigation guidance law can be improved to adapt to varying conditions.In order to obtain the prediction of the velocity profile, the velocity differential equation to the downrange is derived, which can be numerically integrated between the current downrange and the target position by the on-board computer.Then, a third-order polynomial is introduced to fit the velocity profile in order to calculate the future mean velocity.At the beginning of each guidance loop, the future mean velocity is predicted and the time-to-go information is updated, based on which a novel biased proportional navigation guidance law is established to achieve the impact time constraint.Finally,numerical simulation results verified the effectiveness of the time-to-go estimation algorithm and the proposed law. 展开更多
关键词 GUIDANCE Homing missiles Impact time Proportional navigation guidance Time-varying velocity
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Review of High Voltage Direct Current Cables 被引量:6
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作者 George Chen Miao Hao +3 位作者 zhiqiang xu Alun Vaughan Junzheng Cao Haitian Wang 《CSEE Journal of Power and Energy Systems》 SCIE 2015年第2期9-21,共13页
Increased renewable energy integration and international power trades have led to the construction and development of new HVDC transmission systems.HVDC cables,in particular,play an important role in undersea power tr... Increased renewable energy integration and international power trades have led to the construction and development of new HVDC transmission systems.HVDC cables,in particular,play an important role in undersea power transmission and offshore renewable energy integration having lower losses and higher reliability.In this paper,the current commercial feasibility of HVDC cables and the development of different types of HVDC cables and accessories are reviewed.The non-uniform electric field distribution caused by the applied voltage,temperature dependent conductivity,and space charge accumulation is briefly discussed.Current research in HVDC cable for higher operation voltage level and larger power capacity is also reviewed with specific focus on the methodologies of space charge suppression for XLPE extruded cables. 展开更多
关键词 ACCESSORY CONDUCTIVITY DC cable HVDC INSULATION pulse electroacoustic method space charge
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Oxidation of amorphous alloys 被引量:3
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作者 zhiqiang xu Yifei xu +2 位作者 An Zhang Jiangyong Wang Zumin Wang 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2018年第11期1977-2005,共29页
Owing to their unique short-or medium-range ordered microstructures and excellent mechanical, physical, and chemical properties, amorphous alloys have attracted significant interest in recent years. For the applicatio... Owing to their unique short-or medium-range ordered microstructures and excellent mechanical, physical, and chemical properties, amorphous alloys have attracted significant interest in recent years. For the application of amorphous alloys, clarifying their oxidation processes and mechanisms is necessary since many of the surface-related properties of amorphous alloys largely depend on the surface oxide layer.The aim of this paper is to review the recent research on the thermal oxidation behaviors of amorphous alloys under pure oxygen or air condition. The contents are divided into three categories according to the number of components the research considers, i.e., the oxidation of binary, ternary, and multi-component(>3) amorphous alloys. Each section discusses the thermal stability of the amorphous matrix, oxidation kinetics, and the oxide layer and amorphous substrate, which are strongly affected by internal factors(i.e., alloy elements and microstructure) and external factors(i.e., oxidation temperature, duration, and oxygen partial pressure, etc.). The general features of the oxidation of amorphous alloys – from simple binary to complex multi-component amorphous alloys – will be summarized. This overview of the current scientific understanding on the fundamentals of these materials may provide guidelines for the development of strongly corrosion-resistant amorphous alloys. 展开更多
关键词 表面氧化物 合金元素 非结晶 二进制代码 微观结构 氧化动力学 应用程序 氧化行为
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THE PERFORMANCE OF ORTHOGONAL MULTI-MATCHING PURSUIT UNDER THE RESTRICTED ISOMETRY PROPERTY 被引量:2
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作者 zhiqiang xu 《Journal of Computational Mathematics》 SCIE CSCD 2015年第5期495-516,共22页
直角的多匹配的追求(OMMP ) 是直角的匹配追求(OMP ) 的自然扩展 .We 作为 M 1 是一个整数的 OMMP (M) 与参数 M 表示 OMMP。OMP 和 OMMP (M) 之间的主要差别是 OMMP (M) 每重复选择 M 原子,当 OMP 仅仅把一个原子加到最佳的原子集合... 直角的多匹配的追求(OMMP ) 是直角的匹配追求(OMP ) 的自然扩展 .We 作为 M 1 是一个整数的 OMMP (M) 与参数 M 表示 OMMP。OMP 和 OMMP (M) 之间的主要差别是 OMMP (M) 每重复选择 M 原子,当 OMP 仅仅把一个原子加到最佳的原子集合时。在这份报纸,我们学习直角的多匹配的追求的表演在下面裂开。特别地,我们看那测量矩阵 A 是否满足(25 年代, 1/10 ) 有 12 能恢复的 M0 = 的 -RIP, OMMP (M0 ) 在 s 重复以内的 s 稀少的信号。我们而且证明 OMMP (M) 能为 M 的一个大班在 O (s/M ) 重复以内恢复 s 稀少的信号。[从作者抽象] 展开更多
关键词 正交 性能 等距 迭代方法 匹配追踪 OMP 集合运算 原子
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