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| 1 | The Bonnesen isoperimetric inequality in a surface of constant curvature显示文摘We first estimate the containment measure of a convex domain to contain in another in a surface X of constant curvature.Then we obtain the analogue of the known Bonnesen isoperimetric inequality for convex domain in X.Finally we strengthen the known Bonnesen isoperimetric inequality. | ZENG ChunNa MA Lei ZHOU JiaZu CHEN FangWeit | 2012 | Science China Mathematics2012，55，9： | 18 |
| 2 | Adaptive optimization methodology based on Kriging modeling and a trust region method显示文摘Surrogate-Based Optimization(SBO) is becoming increasingly popular since it can remarkably reduce the computational cost for design optimizations based on high-fidelity and expensive numerical analyses. However, for complicated optimization problems with a large design space, many design variables, and strong nonlinearity, SBO converges slowly and shows imperfection in local exploitation. This paper proposes a trust region method within the framework of an SBO process based on the Kriging model. In each refinement cycle, new samples are selected by a certain design of experiment method within a variable design space, which is sequentially updated by the trust region method. A multi-dimensional trust-region radius is proposed to improve the adaptability of the developed methodology. Further, the scale factor and the limit factor of the trust region are studied to evaluate their effects on the optimization process. Thereafter, different SBO methods using error-based exploration, prediction-based exploitation, refinement based on the expected improvement function, a hybrid refinement strategy, and the developed trust-regionbased refinement are utilized in four analytical tests. Further, the developed optimization methodology is employed in the drag minimization of an RAE2822 airfoil. Results indicate that it has better robustness and local exploitation capability in comparison with those of other SBO | Chunna LI Qifeng PAN | 2019 | Chinese Journal of Aeronautics2019，32，2： | 13 |
| 3 | A study of morphing aircraft on morphing rules along trajectory显示文摘Morphing aircraft can meet requirements of multi-mission during the whole flight due to changing the aerodynamic shape,so it is necessary to study itsmorphing rules along the trajectory.However,trajectory planning considering morphing variables requires a huge number of expensive CFD computations due to the morphing in view of aerodynamic performance.Under the given missions and trajectory,to alleviate computational cost and improve trajectory-planning efficiency formorphing aircraft,an offline optimizationmethod is proposed based onMulti-Fidelity Kriging(MFK)modeling.The angle of attack,Mach number,sweep angle and axial position of the morphing wing are defined as variables for generating training data for building the MFK models,in which many inviscid aerodynamic solutions are used as low-fidelity data,while the less high-fidelity data are obtained by solving viscous flow.Then the built MFK models of the lift,drag and pressure centre at the different angles of attack andMach numbers are used to predict the aerodynamic performance of the morphing aircraft,which keeps the optimal sweep angle and axial position of the wing during trajectory planning.Hence,themorphing rules can be correspondingly acquired along the trajectory,aswell as keep the aircraftwith the best aerodynamic performance during thewhole task.The trajectory planning of amorphing aircraft was performed with the optimal aerodynamic performance based on the MFK models,built by only using 240 low-fidelity data and 110 high-fidelity data.The results indicate that a complex trajectory can take advantage of morphing rules in keeping good aerodynamic performance,and the proposed method is more efficient than trajectory optimization by reducing 86%of the computing time. | Xiaoyu CHEN Chunna LI Chunlin GONG Liangxian GU Andrea Da RONCH | 2021 | Chinese Journal of Aeronautics2021，34，7： | 8 |
| 4 | Effect of polycarboxylate-type superplasticizer on the paste fluidity based on the water film thickness of flocs显示文摘The excess water film theory and the properties of flocs are integrated to examine the effect of the polycarboxylate-type superplasticizer on the paste fluidity.The theory states that excess water can surround the flocs rather than the particles and that the cell consists of a floc and a superficial water film.Experiments on limestone powder pastes were conducted to verify the theory.The superplasticizer dosage(sp%)and the water–powder ratio by volume(Vw/Vp)were systematically varied.A sedimentation balance method was used to measure the size distribution of the flocs in the limestone powder pastes.The water film thickness(WFT)of flocs was then calculated and shown to determine the paste fluidity.Based on this WFT of flocs,the effect of the sp on the paste fluidity was determined and then compared with the effect of water. | WU Qiong AN XueHui LIU ChunNa | 2014 | Science China(Technological Sciences)2014，57，8： | 7 |
| 5 | Distribution and risk factor analysis for-associated diarrhea among hospitalized children over one year of age显示文摘Importance: Clostridium difficile-associated diarrhea (CDAD) is a severe type of antibiotic-associated diarrhea (AAD). However, the risk factors for CDAD in children with AAD have not yet been clarified.Objective: To investigate the distribution and risk factors for CDAD among hospitalized children in Beijing Children’s Hospital.Methods: Stool samples from 197 children with AAD were tested for theC. difficile pathogenic genes (tcdA, tcdB, tcdC, tcdD, tcdE, cdtA, andcdtB) using polymerase chain reaction between January 2011 and January 2014. Children who tested positive fortcdA ortcdB were included in the CDAD group, and those remaining comprised the non-CDAD group.Results: The rate of CDAD among the 197 children with AAD was 42.6% (84/197). The age distribution was 1-15.6 years, among which the majority of children (54.8%, 46/84) were aged 1-4 years. Differences in the CDAD-positive rates among AAD children belonging to different age groups were not statistically significant. Univariate analysis revealed that the duration of antibiotic therapy, the length of hospitalization prior to diarrhea, and gastrointestinal tract operations were significant risk factors (P < 0.05). Children with CDAD underwent more antibiotic therapy and had longer periods of hospitalization prior to diarrhea onset than children in the non-CDAD group. Using multivariate regression analysis, hospitalization for ≥ 10 days prior to diarrhea was found to be an independent risk factor for CDAD.Interpretation: This study revealed that the length of hospitalization (≥ 10 days) prior to diarrhea was an independent risk factor for CDAD in children with AAD. | Chunna Zhao Shu Guo Xiaoyun Jia Xiwei Xu | 2020 | Pediatric Investigation2020，4，1： | 2 |
| 6 | Closed-form solutions to fractional-order linear differential equations显示文摘The definitions and properties of widely used fractional-order derivatives are summarized in this paper.The characteristic polynomials of the fractional-order systems are pseudo-polynomials whose powers of the complex variable are non-integers.This kind of systems can be approximated by high-order integer-order systems,and can be analyzed and designed by the sophisticated integer-order systems methodology.A new closed-form algorithm for fractional-order linear differential equations is proposed based on the definitions of fractional-order derivatives,and the effectiveness of the algorithm is illustrated through examples. | Chunna ZHAO Dingyu XUE | 2008 | Frontiers of Electrical and Electronic Engineering in China2008，3，2： | 2 |
| 7 | A low-profile branched monopole laptop reconfigurable multiband antenna for wireless applications 显示文摘 | Zhang Chunna Yang Songnan E1-Ghazaly S | 2009 | IEEE Antennas and Wireless Propagation Letters2009，8，： | 1 |
| 8 | A reconfigurable multiband patch antenna for wireless ap- plications using MEMS switches显示文摘 | Zhang Chunna Yang Songnan Pan H K | 2009 | Microwave and Op- tical Technology Letters2009，51，8： | 1 |
| 9 | Fast interactive segmentation algorithm of image sequences based on relative fuzzy connectedness显示文摘A fast interactive segmentation algorithm of imagesequences based on relative fuzzy connectedness is presented. In comparison with the original algorithm, the proposed one, with the same accuracy, accelerates the segmentation speed by three times for single image. Meanwhile, this fast segmentation algorithm is extended from single object to multiple objects and from singleimage to imagesequences. Thus the segmentation of multiple objects from complex background and batch segmentation of imagesequences can be achieved. In addition, a postprocessing scheme is incorporated in this algorithm, which extracts smooth edge with onepixelwidth for each segmented object. The experimental results illustrate that the proposed algorithm can obtain the object regions of interest from medical image or imagesequences as well as manmade images quickly and reliably with only a little interaction. | Tian Chunna Gao Xinbo | 2005 | Journal of Systems Engineering and Electronics2005，16，4： | 1 |
| 10 | Influenza vaccine effectiveness against medically-attended influenza illness during the 2012 -2013 season in Beijing, China 显示文摘 | Peng Y Mark GT Chunna M | 2014 | Vaccine2014，，7： | 1 |
| 11 | Role of Mesenchymal Stem Cells in Immunological Rejection of Organ Transplantation显示文摘 | Xiaomin Zhang Chunna Jiao Shaozhen Zhao | 2009 | Stem Cell Reviews and Reports2009，，4： | 1 |
| 12 | Life-Cycle Assessment of Concrete Dam Construction: Comparison of Environmental Impact of Rock-Filled and Conventional Concrete显示文摘 | Chunna Liu Changbum R. Ahn Xuehui An SangHyun Lee | 2013 | Journal of Construction Engineering and Management2013，，： | 1 |
| 13 | A Hu sheep genome with the first ovine Y chromosome reveal introgression history after sheep domestication显示文摘The Y chromosome plays key roles in male fertility and reflects the evolutionary history of paternal lineages.Here,we present a de novo genome assembly of the Hu sheep with the first draft assembly of ovine Y chromosome(o MSY),using nanopore sequencing and Hi-C technologies.The o MSY that we generated spans 10.6 Mb from which 775 Y-SNPs were identified by applying a large panel of whole genome sequences from worldwide sheep and wild Iranian mouflons.Three major paternal lineages(HY1a,HY1b and HY2)were defined across domestic sheep,of which HY2 was newly detected.Surprisingly,HY2 forms a monophyletic clade with the Iranian mouflons and is highly divergent from both HY1a and HY1b.Demographic analysis of Y chromosomes,mitochondrial and nuclear genomes confirmed that HY2 and the maternal counterpart of lineage C represented a distinct wild mouflon population in Iran that diverge from the direct ancestor of domestic sheep,the wild mouflons in Southeastern Anatolia.Our results suggest that wild Iranian mouflons had introgressed into domestic sheep and thereby introduced this Iranian mouflon specific lineage carrying HY2 to both East Asian and Africa sheep populations. | Ran Li Peng Yang Ming Li Wenwen Fang Xiangpeng Yue Hojjat Asadollahpour Nanaei Shangquan Gan Duo Du Yudong Cai Xuelei Dai Qimeng Yang Chunna Cao Weidong Deng Sangang He Wenrong Li Runlin Ma Mingjun Liu Yu Jiang | 2021 | Science China(Life Sciences)2021，64，7： | 1 |
| 14 | To Strengthen Quality Education, We Must Start with Optimizing the Curricular Structure显示文摘 | Wang Chunna | 1997 | Chinese Education & Society1997，，6： | 1 |
| 15 | Reeonfigurable antenna for simultaneous multi-service wirelexs applications显示文摘 | Zhang Chunna Yang Songnan | 2007 | Radio and Wireless Symposium2007，，7： | 1 |
| 16 | The characteristics of GaN-based blue LED on Si substrate显示文摘 | Xiong Chuanbing Jiang Fengyi Fang Wenqing Wang Li Mo Chunna Liu Hechu | 2007 | Journal of Luminescence2007，，： | 1 |
| 17 | Effect of growth temperature on properties of single crystalline ZnO films prepared by atmospheric MOCVD显示文摘 | Xiong Chuanbing Fang Wenqing Pu Yong Dai Jiangna Wang Li Mo Chunna Jiang Fengyi | 2004 | Chinese Journal of Semiconductors2004，25，12： | 1 |
| 18 | On strongly :- clean rings 显示文摘 | LI Chunna ZHOU Yiqiang | 2011 | Algebra Appl2011，38，10： | 1 |
| 19 | Frequency reconfigurable antennas for multiradio wireless platforms 显示文摘 | YANG Songnan ZHANG Chunna PAN Helen | 2009 | IEEE Microwave Mag2009，10，1： | 1 |
| 20 | Modulation of morphology and electronic structure on MoS_(2)-based electrocatalysts for water splitting显示文摘Electrocatalytic water splitting into hydrogen is one of the most favorable approaches to produce renewable energy.MoS_(2)has received great research attention for both hydrogen evolution reaction(HER)and oxygen evolution reaction(OER)due to its unique structure and ability to be chemically modified,enabling its electrocatalytic activity to be further enhanced or made comparable to that of Pt-based materials.In this review,we discuss the important fabrication approaches of MoS_(2)ultrathin nanosheet(MoS_(2)NS)to improve the intrinsic catalytic activity of bulk MoS_(2).Moreover,several modification strategies involve either morphology modulation or electron structural modulation to improve the charge transfer kinetics,including doping,vacancy,and heterojunction construction or single-atom anchor.Our perspectives on the key challenges and future directions of developing high-performance MoS_(2)-based electrocatalysts for overall water splitting are also discussed. | Mengmeng Liu Chunyan Zhang Ali Han Ling Wang Yujia Sun Chunna Zhu Rui Li Sheng Ye | 2022 | Nano Research2022，15，8： | 1 |
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