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Parameter studies and evaluation principles of delamination damage in laminated composites

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Chinese Journal of Aeronautics 2021年第7期34卷 62-72页

作者： kangkang wang Libin ZHAO Haiming HONG Jianyu ZHANG Yu GONG School of Astronautics Beihang UniversityBeijing 100083China Shenyang Aircraft Design and Research Institute Shenyang 110035China College of Aerospace Engineering Chongqing UniversityChongqing 400044China

Delamination represents one of the most severe failure modes in composite laminates,especially when they are subjected to uniaxial compression *** evaluation of the delamination damage has always been an essential issue of composite laminates for durability and damage tolerance in engineering *** on the most typical and representative elliptical delamination issue,an analytical model simultaneously considering the conservative buckling process and non-conservative delamination propagation process is *** computational cases considering different delamination depths,directions,aspect ratios,and areas are established,and the predicted results based on the analytical model are carefully *** of these geometrical delamination parameters on the buckling,delamination propagation,and failure behaviors of composite laminates are thoroughly analyzed,and innovative evaluation principles of the delamination damage have been *** is found that the delamination area is the key factor that truly affecting the failure behaviors of delaminated composites,and the local/global buckling and failure loads show clear linearity with the delamination area,whilst the delamination depth and direction only have slight effects.

关键词： Analytical model Composite Delamination Evaluation principles Parameter study

A Facile Route to Synthesize Sheet-like Na2Ti3O7 with Improved Sodium Storage Properties

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Chemical Research in Chinese Universities 2015年第3期31卷 443-446页

作者： XIE Man wang kangkang CHEN Renjie LI Li WU Feng Beijing Key Laboratory of Environmental Science and Engineering School of Chemical Engineering and Environment National Development Center of High Technology Green Materials Beijing Institute of Technology Beijing 100081 P. R. China

A high purity sheet-like Na2Ti307 material was synthesized by a new facile solid-state method with hollow sphere TiO2 as titanium source. X-Ray diffraction（XRD） measurement proves that no impurity phase existed when the sample was heated at 900 ℃. Charge/discharge measurement was performed in a potential range of 0.01m2.5 V at different current-rates（C-rates）. The initial charge/discharge capacities are 191/424 mA.h/g at 0.1 C and still remain as high as 101 mA.h/g after 50 cycles. CV test proves that the large irreversible capacity in the initial cycle results from the formation of the solid electrolyte interface（SEI）. However, the electrode presents an increased initial cou- lombic efficiency in a 1 mol/L NaPF6 electrolyte compared to that in a 1 mol/L NaCIO4 electrolyte.

关键词： Na2Ti307 Sodium-ion battery Anode Hollow sphere TiO2

Proximal Point-Like Method for Updating Simultaneously Mass and Stiffness Matrices of Finite Element Model

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Transactions of Nanjing University of Aeronautics and Astronautics 2020年第1期37卷 1-12页

作者： DAI Hua wang kangkang College of Science Nanjing University of Aeronautics and AstronauticsNanjing 211106P.R.China

The problem of correcting simultaneously mass and stiffness matrices of finite element model of undamped structural systems using vibration tests is considered in this *** desired matrix properties,including satisfaction of the characteristic equation,symmetry,positive semidefiniteness and sparsity,are imposed as side constraints to form the optimal matrix pencil approximation *** partial Lagrangian multipliers,we transform the nonlinearly constrained optimization problem into an equivalent matrix linear variational inequality,develop a proximal point-like method for solving the matrix linear variational inequality,and analyze its global *** results are included to illustrate the performance and application of the proposed method.

关键词： model updating proximal point method optimal matrix pencil approximation matrix linear variational inequality

The evolution and diurnal expression patterns of photosynthetic pathway genes of the invasive alien weed,Mikania micrantha

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Journal of Integrative Agriculture 2024年第2期23卷 590-604页

作者： kangkang wang Mengjiao Jin Jingjing Li Yesong Ren Zaiyuan Li Xinghai Ren Cong Huang Fanghao Wan Wanqiang Qian Bo Liu Shenzhen Branch Guangdong Laboratory of Lingnan Modern Agriculture/Genome Analysis Laboratory of the Ministry of Agriculture and Rural AffairsAgricultural Genomics Institute at ShenzhenChinese Academy of Agricultural SciencesShenzhen 518120China State Key Laboratory of Crop Stress Adaptation and Improvement School of Life SciencesHenan UniversityKaifeng 475004China Shenzhen Research Institute of Henan University Shenzhen 518000China

Mikania micrantha is a fast-growing global invasive weed species that causes severe damage to natural ecosystems and very large economic losses of forest and crop *** has advantages in photosynthesis,including a similar net photosynthetic rate as C4 plants and a higher carbon fixation *** used a combination of genomics and transcriptomics approaches to study the evolutionary mechanisms and circadian expression patterns of *** ***,16 positive selection genes focused on photoreaction and utilization of *** different tissues,98.1%of the genes associated with photoresponse had high expression in stems,and more than half of the genes of the C4 cycle had higher expression in stems than in *** stomatal opening and closing,2 genes of carbonic anhydrase(CAs)had higher expression at 18:00 than at 8:00,and the slow anion channel 1(SLAC1)and high-leaf-temperature 1 kinase(HT1)genes were expressed at low levels at 18:*** addition,genes associated with photosynthesis had higher expression levels at 7:00 and 17:*** hypothesized that *** may undergo photosynthesis in the stem and flower organs and that some stomata of the leaves were opening at night by CO_(2)*** addition,its evolution may attenuate photoinhibition at high light intensities,and enhance more efficient of photosynthesis during low light *** the tissue-specific photosynthetic types and different diurnal pattern of photosynthetic-related genes may contribute to its rapid colonization of new habitats of ***.

关键词： invasion plant Mikania micrantha photosynthesis stomata stem

弹力带柔性抗阻训练对中老年女性骨密度和跌倒风险指数的影响

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武汉体育学院学报 2014年第1期48卷 91-95页

作者：王康康河南师范大学体育学院河南新乡453002

探讨弹力带柔性抗阻运动对中老年女性骨密度和跌倒风险指数的影响,为大众健身缓减骨质疏松症提供理论依据.以25名56～72岁中老年女性健身爱好者为研究对象,受试者均无明确诊断的心肺、脑等内脏器官疾病.在试验中,以弹力带柔性抗阻练习... 详细信息

探讨弹力带柔性抗阻运动对中老年女性骨密度和跌倒风险指数的影响,为大众健身缓减骨质疏松症提供理论依据.以25名56～72岁中老年女性健身爱好者为研究对象,受试者均无明确诊断的心肺、脑等内脏器官疾病.在试验中,以弹力带柔性抗阻练习为主要方式,以增加肌肉力量为目的,针对受试者全身的大肌肉群进行分周期、分频度测试.受试者每周进行强度为16RM的训练3-5次,共18周.利用双能X线骨密度仪、平衡训练和测试系统检测受试者的骨密度和跌倒风险指数.采用spss16.0统计学软件计算（-x）±s,配对T检验进行差异性比较.18周弹力带柔性抗阻训练后中老年女性训练者的各项骨强度较实验前均有显著性增高,跌倒风险指数较实验前有非常显著性降低,参训者的平衡能力得到提升,最终有效的达到预防中老年女性人群摔倒和大大降低骨折发生的目的.

关键词：柔性抗阻弹力带中老年女性骨密度跌倒风险指数