检索结果-南通市图书馆

Science China Earth Sciences 2011年第7期54卷 1095-1104页

作者： SHEN BaiZhu LIN ZhongDa LU RiYu lian yi Institute of Meteorological Science of Jilin Province Changchun 130062 China Laboratory of Research for Mid-High Latitude Circulation System and East Asian Monsoon Changchun 130062 China Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

Summer rainfall is vital for crops in Northeast China. In this study, we investigated large-scale circulation anomalies related to monthly summer rainfall in Northeast China using European Center for Medium-Range Weather Forecast ERA-40 reanalysis data and monthly rainfall data from 79 stations in Northeast China. The results show that the interannual variation in rainfall over Northeast China is mainly dominated by a cold vortex in early summer (May-june) and by the East Asian summer monsoon in late summer (July-August). In early summer, corresponding to increased rainfall in Northeast China, an anomalous cyclonic anomaly tilted westward with height appears to the northwest and cold vortices occur frequently. In late summer, the rainfall anomaly is mainly controlled by a northward shift of the local East Asian jet stream in the upper troposphere and the northwest extension of the western Pacific subtropical high (WPSH) in the lower troposphere. The enhanced southwesterly anomaly in the west of the WPSH transports more moisture into Northeast China and results in more rainfall. In addition, compared with that in July, the rainfall in Northeast China in August is also influenced by a mid- and high-latitude blocking high over Northeast Asia.

关键词： summer rainfall Northeast China interannual variation cold vortex western Pacific subtropical high East Asian jetstream

GSM-MRF based classification approach for real-time moving object detection

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第2期9卷 250-255页

作者： Xiang PAN yi-jun WU Institute of Information and Communication Engineering Zhejiang University Hangzhou 310027 China

Statistical and contextual information are typically used to detect moving regions in image sequences for a fixed *** this paper,we propose a fast and stable linear discriminant approach based on Gaussian Single Model(GSM)and Markov Random Field(MRF).The performance of GSM is analyzed first,and then two main improvements corresponding to the drawbacks of GSM are proposed:the latest filtered data based update scheme of the background model and the linear classification judgment rule based on spatial-temporal feature specified by *** results show that the proposed method runs more rapidly and accurately when compared with other methods.

关键词： Moving object detection Markov Random Field (MRF) Gaussian Single Model (GSM) Fisher Linear Discriminant Analysis (FLDA)

Drop impact dynamic and directional transport on dragonfly wing surface

在线全文

学校读者我要写书评

暂无评论

Friction 2023年第5期11卷 737-747页

作者： Jing XU Wenjun LIU Weixiao SHANG jun CHEN Jiadi lian School of Mechanical Engineering Hangzhou Dianzi UniversityHangzhou 310018China School of Mechanical Engineering Purdue UniversityWest LafayetteIndiana 47907USA College of Mechanical and Electrical Engineering China Jiliang UniversityHangzhou 310018China

The ability of dragonflies to fly in the rain without being wetted by raindrops has motivated researchers to investigate the impact behavior of a drop on the superhydrophobic wings of *** superhydrophobic surface is used as a reference for the design of directional surfaces and has attracted extensive attention owing to its wide applicability in microfluidics,self-cleaning,and other *** this study,the static contact angle and rebound process of a drop impacting a dragonfly wing surface are investigated experimentally,whereas the wetting pressure,Gibbs free energy,and Stokes number *** of restitution are theoretically calculated to examine the dynamic and unidirectional transport behaviors of the *** show that the initial inclination angle of the dragonfly wing is similar to the sliding angles along with the drop *** water drop bounces from the bottom of the dragonfly wing to the distal position,demonstrating directional *** drop impacts the dragonfly wing surface,and the drop exhibits compression,recovery,and separation phases;in these three phases,the drop morphology *** the Gibbs free energy and cross-sectional area evolve,the coefficient of restitution decreases as the drop continues to bounce,and the Stokes number increases.

关键词： dragonfly wing superhydrophobic wettability directional transport bounce

Optimal Dividend and Dynamic Reinsurance Strategies with Capital Injections and Proportional Costs

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Acta Mathematicae Applicatae Sinica 2012年第3期28卷 505-524页

作者： yi-dong WU jun-yi GUO School of Mathematical Sciences and LPMC Nankai UniversityTianjin 300071China School of Economics Yunnan UniversityKunming 650091China

We consider an optimization problem of an insurance company in the diffusion setting, which controls the dividends payout as well as the capital injections. To maximize the cumulative expected discounted dividends minus the penalized discounted capital injections until the ruin time, there is a possibility of （cheap or non-cheap） proportional reinsurance. We solve the control problems by constructing two categories of suboptimal models, one without capital injections and one with no bankruptcy by capital injection. Then we derive the explicit solutions for the value function and totally characterize the optimal strategies. Particularly, for cheap reinsurance, they axe the same as those in the model of no bankruptcy.

关键词： proportional reinsurance non-cheap optimal dividend capital injections

Hepatitis E virus chimeric DNA vaccine elicits immunologic response in mice

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2005年第42期11卷 6713-6715页

作者： Yan Hong Bing Ruan lian-Hua Yang Yong Chen Luo Jing yi-Ting Wang Hua-jun Hu Institute of Bioengineering.ZhejiangAcademy of Medical Sciences Hangzhou 310013 ZhejiangProvince China Zhejiang University Medical School Hangzhou310003 Zhejiang Province China

AIM： To construct the plasmid pcHEV23 containing fragments of HEV ORF2 and ORF3 chimeric gene and to assess its ability to elicit specific immunologic response in mice. METHODS： The gene encoding the structural protein of HEV ORF2 fragment and full-length ORF3 was amplified by PCR. The PCR products were cloned into an eucaryotic expression plasmid pcDNA3. The resulting plasmid pcHEV23 was used as a DNA vaccine to inoculate BALB/c mice intramuscularly thrice at a dose of 100 or 200 ug. Mice injected with empty pcDNA3 DNA or saline served as control and then specific immune responses in the mice were detected. RESULTS： After 2-3 times of inoculation, all mice injected with pcHEV23 had anti-HEV IgG seroconversion and specific T lymphocyte proliferation. The lymphocyte stimulation index in the group immunized with pcHEV23 （3.1＋0.49） was higher than that in the control group （0.787±0.12, P〈0.01）. None in the control group had a detectable level of anti-HEV IgG. CONCLUSION： DNA vaccine containing HEV ORF2 and ORF3 chimeric gene can successfully induce specific humoral and cellular immune response in mice.

关键词： Hepatitis E virus Animals Female Humans Lymphocyte Activation Mice Mice, Inbred BALB C Open Reading Frames Plasmids Recombinant Fusion Proteins Research Support, Non-U.S. Gov't T-Lymphocytes Vaccines, DNA Viral Hepatitis Vaccines

Stable Label-Specific Features Generation for Multi-Label Learning via Mixture-Based Clustering Ensemble

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2022年第7期9卷 1248-1261页

作者： yi-Bo Wang jun-yi Hang Min-Ling Zhang School of Computer Science and Engineering Southeast UniversityNanjing 210096China IEEE

Multi-label learning deals with objects associated with multiple class labels,and aims to induce a predictive model which can assign a set of relevant class labels for an unseen *** each class might possess its own characteristics,the strategy of extracting label-specific features has been widely employed to improve the discrimination process in multi-label learning,where the predictive model is induced based on tailored features specific to each class label instead of the identical instance *** a representative approach,LIFT generates label-specific features by conducting clustering ***,its performance may be degraded due to the inherent instability of the single clustering *** improve this,a novel multi-label learning approach named SENCE(stable label-Specific features gENeration for multi-label learning via mixture-based Clustering Ensemble)is proposed,which stabilizes the generation process of label-specific features via clustering ensemble ***,more stable clustering results are obtained by firstly augmenting the original instance repre-sentation with cluster assignments from base clusters and then fitting a mixture model via the expectation-maximization(EM)*** experiments on eighteen benchmark data sets show that SENCE performs better than LIFT and other well-established multi-label learning algorithms.

关键词： Clustering ensemble expectation-maximization al-gorithm label-specific features multi-label learning

Inhibition of trehalase affects the trehalose and chitin metabolism pathways in Diaphorina citri(Hemiptera:Psyllidae)

在线全文

学校读者我要写书评

暂无评论

Insect Science 2021年第3期28卷 718-734页

作者： Hai-Zhong Yu Yu-Ling Huang Zhan-jun Lu Qin Zhang Hua-Nan Su yi-Ming Du Long yi Ba-lian Zhong Ci-Xiang Chen College of Life Sciences Gannan Normal UniversityGanzhouJiangxiChina National Navel Orange Engineering Research Center GanzhouJiangxiChina China-USA Citrus Huanglongbing Joint Laboratory A Joint Laboratory of The University of Florida and Gannan Normal UniversityGanzhouJiangxiChina Fruit Bureau of Ganzhou GanzhouJiangxiChina

The Asian citrus psyllid,Diaphorina citri is the principal vector of huanglongbing,which transmits Candidatus Liberibacter *** is a key enzyme involved in trehalose hydrolysis and plays an important role in insect growth and *** specific functions of this enzyme in *** have not been *** this study,three trehalase genes(DcTreJ-1,DcTrel-2,and DcTre2)were identified based on the *** genome *** analysis showed that DcTrel-1 and DcTrel-2 are related to soluble trehalase,whereas DcTre2 is associated with membrane-bound *** expression analysis indicated that DcTrel-1 and DcTrel-2 had the highest expression levels in the head and wing,respectively,and DcTre2 had high expression levels in the fat ***,DcTrel-1 and DcTrel-2 expression levels were induced by 20-hydroxyecdysone and juvenile hormone III,but DcTre2 was *** expression levels of DcTrel-1,DcTrel-2,and DcTre2 were significantly up-regulated,which resulted in high mortality after treatment with *** activities and glucose contents were downregulated,but the trehalose content increased after treatment with *** addition,the expression levels of chitin metabolism-related genes significantly decreased at 24 and 48 h after treatment with ***,silencing of DcTrel-1,DcTrel-2,and DcTre2 reduced the expression levels of chitin metabolism-related genes and led to a malformed phenotype of *** results indicate that *** trehalase plays an essential role in regulating chitin metabolism and provides a new target for control of ***.

关键词： chitin metabolism Diaphorina citric RNA interference trehalase validamycin

Development cost prediction of general aviation aircraft using combined estimation technique

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2021年第4期34卷 32-41页

作者： Xiaonan CHEN jun HUANG Mingxu yi School of Aeronautic Science and Engineering Beihang UniversityBeijing 100083China

Obtaining accurate development cost estimation results of general aviation aircraft is crucial for companies to adopt the best strategy in the development *** address this problem,this paper proposes a combination of three commonly used single prediction *** optimal weight values of the three single prediction methods are determined by utilizing the shortest ideal point *** cost datasets collected from literature are utilized for fitting and testing the combined prediction method,and the weight coefficients of the three individual prediction methods are calculated as 0.6859,0.0035 and 0.3106,*** results of this study indicate that the developed method has better fitting and estimation accuracy than that of the three individual methods,with average fitting and predicting error values of 2.60%and 6.43%,***,the cost data of military and civil aircraft development from literature are collected for *** results further confirm that the proposed method is not only superior to the single prediction methods in terms of high precision but has wider *** importantly,this research can provide important reference for general aviation aircraft companies in term of product cost planning and corporate sales strategies.

关键词： Combined prediction method General aviation aircraft Optimal weight Shortest ideal point method

An Objective Measure to Evaluate Actual Body Shape among Children and Adolescents in China

在线全文

学校读者我要写书评

暂无评论

Biomedical and Environmental Sciences 2014年第8期27卷 582-593页

作者： FU lian Guo WANG Hai jun LI Xiao Hui WANG Zhi Qiang Patrick WC Lau YANG yi De MENG Xiang Kun MA jun Institute of Child and Adolescent Health School of Public Health Peking University Health Science Center Centre for Chronic Disease School of Medicine University of Queensland Department of Physical Education Hong Kong Baptist University

Objective The purpose of this study was to explore an objective measure to assess actual body shape of children and adolescents in China. Methods Based on the Chinese National Survey on Student＇s Constitution and Health （CNSSCH） in 2005, 210 927 children and adolescents＇（7-18 years） body height, body weight, chest circumference, sitting height, chest circumference-height ratio, chest circumference-sitting height ratio, chest circumference-low limb ratio, and sitting height-low limb ratio measurements were used to develop an objective measure by using transformation variables and explored factor analysis （EFA）. Discrimination power of the objective measure was evaluated based on BMI reference and Receiver Operating Characteristic curves （ROC）. Results The objective measure included four dimensions scores：transverse dimension （TD） indicating weight and chest circumference; length dimension （LD） indicating height and sitting height;transverse-length ratio dimension （TLD） indicating chest circumference-height ratio, chest circumference-sitting height and chest circumference-low limb ratio; proportion dimension （PD） indicating sitting height-low limb ratio. The whole dimension （WD） indicating the whole body shape was showed by the average of four dimensions scores. Four dimensions and WD scores were approximately 80 in children and adolescents with normal weight, and higher than those of overweight, obesity, and underweight （all P-values〈0.001）. Areas under ROC of overweight and obesity compared with normal weight ranged from 0.88 to 1.00 for scores of TD, TLD, and WD. Conclusion The objective measure which included four dimensions was explored, and TD, TLD, and WD had significant discrimination power.

关键词： Objective measure Body shape Children and adolescents

Preparation of Hydrophilic UHMWPE Hollow Fiber Membranes by Chemically Bounding Silica Nanoparticles

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2021年第2期39卷 189-200,I0006页

作者： lian-lian Fan Jia-You Quan Hao Zhang jun-Rong Yu Zu-Ming Hu Yan Wang Shanghai Collaborative Innovation Center for High Performance Fiber Composites College of Materials Science and EngineeringDonghua UniversityShanghai 201620China Sinochem International Corporation Shanghai 200126China

In this work, ultra-high molecular weight polyethylene (UHMWPE) microfiltration hollow fiber membranes prepared via the thermally induced phase separation (TIPS) method were modified by chemically bounding hydrophilic silica (SiO2) nanoparticles onto the surface to improve anti-fouling performance. A range of testing techniques including attenuated total reflection Flourier transformed infrared spectroscopy(ATR-FTIR), X-ray photoelectron spectroscopy (XPS), field emission scanning electron microscopy (FE-SEM), water contact angle, mechanical test,filtration and anti-fouling performance were carried out to discuss the influence of different modification conditions on the properties of the membranes. The prepared hollow fiber membranes display the significantly excellent performance when the vinyl trimethoxy silane (VTMS) concentration was 13%, the pH value of the hydrolyzate was 4 and the hydrolysis reaction time was 6 h. In particular, the hydrophilicity of modified membranes was improved effectively, resulting in the enhancement of membrane anti-fouling properties. The results of this work can be consulted for improving the anti-fouling performance of the UHMWPE microfiltration hollow fiber membrane applied in the field of water purification.

关键词： Hollow fiber membrane Hydrophilic Anti-fouling Silica(SiO2)nanoparticles Water purification