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24篇 您的检索式:作者名="Xu Zichen"
    题名 作者 年代 出处 被引量
1Inhibition of in-stent restenosis after graphene oxide double-layer drug coating with good biocompatibility显示文摘In this study,we designed a double layer-coated vascular stent of 316L stainless steel using an ultrasonic spray system to achieve both antiproliferation and antithrombosis.The coating included an inner layer of graphene oxide(GO)loaded with docetaxel(DTX)and an outer layer of carboxymethyl chitosan(CMC)loaded with heparin(Hep).The coated surface was uniform without aggregation and shedding phenomena before and after stent expanded.The coating treatment was able to inhibit the adhesion and activation of platelets and the proliferation and migration of smooth muscle cells,indicating the excellent biocompatibility and antiproliferation ability.The toxicity tests showed that the GO/DTX and CMC/Hep coating did not cause deformity and organ abnormalities in zebrafish under stereomicroscope.The stents with GO double-layer coating were safe and could effectively prevent thrombosis and in-stent restenosis after the implantation into rabbit carotid arteries for 4–12 weeks.Shuang Ge Yadong Xi Ruolin Du Yuzhen Ren Zichen Xu Youhua Tan Yazhou Wang Tieying Yin Guixue Wang 2019Regenerative Biomaterials2019,6,5:4
2SYMPLECTIC ANALYSIS FOR WAVE PROPAGATION OF HIERARCHICAL HONEYCOMB STRUCTURES显示文摘Wave propagation in two-dimensional hierarchical honeycomb structures with twoorder hierarchy is investigated by using the symplectic algorithm. By applying the variational principle to the dual variables, the wave propagation problem is transformed into a two-dimensional symplectic eigenvalue problem. The band gaps and spatial filtering phenomena are examined to find the stop bands and directional stop bands. Special attention is directed to the effects of the relative density and the length ratio on the band gaps and phase constant surfaces. This work provides new opportunities for designing hierarchical honeycomb structures in sound insulation applications.Kai Zhang Zichen Deng Xiaojian Xu Xiuhui Hou Junmiao Meng 2015Acta Mechanica Solida Sinica2015,28,3:3
3Particle swarm optimization-based algorithm of a symplectic method for robotic dynamics and control显示文摘Multibody system dynamics provides a strong tool for the estimation of dynamic performances and the optimization of multisystem robot design. It can be described with differential algebraic equations(DAEs). In this paper, a particle swarm optimization(PSO) method is introduced to solve and control a symplectic multibody system for the first time. It is first combined with the symplectic method to solve problems in uncontrolled and controlled robotic arm systems. It is shown that the results conserve the energy and keep the constraints of the chaotic motion, which demonstrates the efficiency, accuracy, and time-saving ability of the method. To make the system move along the pre-planned path, which is a functional extremum problem, a double-PSO-based instantaneous optimal control is introduced. Examples are performed to test the effectiveness of the double-PSO-based instantaneous optimal control. The results show that the method has high accuracy, a fast convergence speed, and a wide range of applications.All the above verify the immense potential applications of the PSO method in multibody system dynamics.Zhaoyue XU Lin DU Haopeng WANG Zichen DENG 2019Applied Mathematics and Mechanics(English Edition)2019,40,1:3
412-Tungstophosphoric acid niched in Zr-based metal-organic framework:a stable and efficient catalyst for Friedel-Crafts acylation显示文摘Heteropoly acids(HPA) are well known for their versatile solid acid catalysis in diverse chemical reactions, however they suffer from low surface area(<10 m^2/g) and leaching into the reactions media, which reduce their prospects as industrial catalyst.Herein, a novel hybrid material HPW@Zr-BTC,composed of 12-tungstophoric acid(HPW) and Zr^(Ⅳ)-benzene tri-carboxylate(Zr-BTC) metal-organic framework(MOF), was prepared via one-pot solvothermal method. Excellent HPW loading up to 32.3 wt% was achieved, and HPW@Zr-BTC composite proved to be highly stable, besides the crystalline morphology of Zr-BTC was intact. The catalytic activity of the hybrid composite was explored via Friedel-Crafts acylation of anisole with benzoyl chloride.The 28.2 wt% HPW@Zr-BTC showed excellent catalytic performance, with 99.4% anisole conversion and 97.6% yield(pmethoxybenzophenone) under solvent free conditions. Excellent retention of catalytic activity was achieved after at least five consecutive runs due to non-observable HPW leaching. The promising activity and stability of the catalyst forecasted its potential industrial applications.Latif Ullah Guoying Zhao Zichen Xu Hongyan He Muhammad Usman Suojiang Zhang 2018Science China Chemistry2018,61,4:2
5Coupling dynamic characteristics of simplified model for tethered satellite system显示文摘connecting wires are the main manifestations of the coupling dynamic effects on the orbit evolution,the attitude adjusting and the flexible vibration of the tethered satellite system.To investigate attitude evolution of the tethered system and the mechanical energy transfer/loss characteristics between the bus system and the solar sail via the connecting wires,a structure-preserving method is developed in this paper.Simplifying the tethered satellite system as a composite structure consisting of a particle and a flexible thin panel connected by four special springs,the dynamic model is deduced via the Hamiltonian variational principle firstly.Then,a structure-preserving approach that connects the symplectic Runge-Kutta method and the multi-symplectic method is developed.The excellent structure-preserving property of the numerical scheme constructed is presented to illustrate the credibility of the numerical results obtained by the constructed structure-preserving approach.From the numerical results on the mechanical energy transfer/loss in the composite structure,it can be found that the mechanical energy transfer tendency in the tethered system is dependent of the initial attitude angle of the system while the total mechanical energy loss of the system is almost independent of the initial attitude angle.In addition,the special stiffness range of the spring is found in the attitude angle evolution of the system,which provides a structural parameter design window for the connecting wires,that is,the duration needed to arrive the stable attitude is short when the stiffness of the wire is designed in this special range.Weipeng Hu Yulu Huai Mengbo Xu Zichen Deng 2021Acta Mechanica Sinica2021,37,8:2
6Bioresponsive nanotherapy for preventing dental caries by inhibiting multispecies cariogenic biofilms显示文摘Early childhood caries(ECC)is a public healthcare concern that greatly reduces the quality of life of young children.As a leading factor of ECC,cariogenic biofilms are composed of acidogenic/aciduric pathogens and extracellular polysaccharides(EPSs),creating an acidic and protected microenvironment.Antimicrobial photodynamic therapy(aPDT)is a noninvasive,painless,and efficient therapeutic approach that is suitable for treating ECC.However,due to the hyperfine structure of cariogenic biofilms,most photosensitizers(PSs)could not access and penetrate deeply in biofilms,which dramatically hamper their efficiency in the clinic.Herein,bioresponsive nanoparticle loaded with chlorin e6(MPP-Ce6)is developed,which largely increases the penetration depth(by over 75%)and retention(by over 100%)of PS in the biofilm compared with free Ce6.Furthermore,MPP-Ce6-mediated aPDT not only kills the bacteria in preformed biofilms but also inhibits multispecies biofilm formation.A rampant caries model is established to mimic ECC in vivo,where the population of cariogenic bacteria is decreased to 10%after MPP-Ce6-mediated aPDT.Importantly,the number and severity of carious lesions are efficiently reduced via Keyes’scoring and micro-CT analysis.This simple but effective strategy can serve as a promising approach for daily oral hygiene in preventing ECC.Danfeng Liu Xianbin Ma Yaoting Ji Rourong Chen Shuhui Zhou Hantao Yao Zichen Zhang Mengjie Ye Zhigang Xu Minquan Du 2022Bioactive Materials2022,7,8:2
7Geological significance of the former Xiong'er Volcanic Belt on the southwestern margin of the North China Craton显示文摘The rock association of low-grade metasedimentary rocks and greenschists located within the Meso- Cenozoic Liupanshan Fault system on the southwestern margin of the North China Craton (NCC)is regarded as part of the Paleoproterozoic Xiong'er Group.These low- grade rocks are separated by normal faults,with the greenschist located in the hanging wails.Zircon LA-ICP- MS U-Pb ages of the greenschists range from 2455 to 423 Ma,suggesting that they are not Paleoproterozoic in age. The protolith ages (206-194 Ma)of the greenschists were determined by LA-ICP-MS U-Pb dating of zircons from two siltstone inteflayers.The petrology and geochemistry of the greenschists reveal that their protolith was continental tholeiitic basalt that formed in an extensional environment such as a continental rift.Thus,it is proposed that the protolith of the greenschists was a mafic volcanic rock of Late Triassic-Early Jurassic age and was metamorphosed during the Jurassic due to tectonism within the Liupanshan tectonic belt.These results show that the greenschists should be reclassified and removed from the Xiong'er Group,and explains why they differ so much from those of typical Xiong'er Group successions in other areas.The formation of the mafic volcanic rocks under conditions of continental rifting differs from that of coeval granitic rocks in the western Qinling Orogen,where the extension occurred during a post-collisional stage in the Late Triassic,which further suggests that the southwestern margin of the NCC became an extensional setting after the Late Triassic.Guanxu CHEN Jinhai LUO Huan XU Jia YOU Yifei LI Zichen CHE 2019Frontiers of Earth Science2019,13,1:1
8Disease resistance conferred by components of essential chrysanthemum oil and the epigenetic regulation of OsTPS1显示文摘The sesquiterpene alpha-bisabolol is the predominant active ingredient in essential oils that are highly valued in the cosmetics industry due to its wound healing,anti-inflammatory,and skin-soothing properties.Alpha-bisabolol was thought to be restricted to Compositae plants.Here we reveal that alpha-bisabolol is also synthesized in rice,a non-Compositae plant,where it acts as a novel sesquiterpene phytoalexin.Overexpressing the gene responsible for the biosynthesis of alpha-bisabolol,Os TPS1,conferred bacterial blight resistance in rice.Phylogenomic analyses revealed that alpha-bisabolol-synthesizing enzymes in rice and Compositae evolved independently.Further experiments demonstrated that the natural variation in the disease resistance level was associated with differential transcription of Os TPS1 due to polymorphisms in its promoter.We demonstrated that Os TPS1 was regulated at the epigenetic level by JMJ705 through the methyl jasmonate pathway.These data reveal the cross-family accumulation and regulatory mechanisms of alpha-bisabolol production.Chuansong Zhan Long Lei Hao Guo Shen Zhou Congping Xu Zixin Liu Zichen Wu Yuan Deng Yuanyuan Miao Yu Han Meng Zhang Hua Li Sishu Huang Chenkun Yang Feng Zhang Yufei Li Ling Liu Xianqing Liu Hafiz Muhammad Khalid Abbas Alisdair R.Fernie Meng Yuan Jie Luo 2023Science China(Life Sciences)2023,66,5:1
9Wave Propagation Characteristics in Thick Conventional and Auxetic Cellular Plates显示文摘Based on Mindlin plate models and Kirchhoff plate models,this study was concerned with the wave propagation characteristics in thick conventional and auxetic cellular structures,with the objective to clarify the effects of negative Poisson's ratio,shear factor and orthotropic mechanical properties on the dynamic behaviors of thick plates.Numerical results revealed that the predictions using variable shear factor in Mindlin plate models resulted in high wave frequencies,which were more significant for plates with negative values of Poisson's ratio.The present study can be useful for the design of critical applications by varying the values of Poisson's ratio.Xiaojian Xu Zichen Deng 2016Acta Mechanica Solida Sinica2016,29,2:1
10Synthesis and characterization of polyurethane/SiO2 nanoeomposites 显示文摘Gao Xiaoyan Zhu Yanchao Zhao Xu Wang Zichen An Dongmin Ma Yuejia 2011Applied Surface Science2011,25,:1
11Superconductivity in ThMo_2Si_2C with Mo_2C square net显示文摘We report the superconductivity of a new quaternary compound ThMo_(2)Si_(2)C, synthesized with the arc-melting technique. The compound crystallizes in a tetragonal CeCr_(2)Si_(2)C-type structure with cell parameters of a = 4.2296A and c = 5.3571 A. An interlayer Si–Si covalent bonding is suggested by the atomic distance. The electrical resistivity and magnetic susceptibility measurements indicate a Pauli-paramagnetic metal with dominant electron-electron scattering in the normal-state. Bulk superconductivity at 2.2 K is demonstrated with a dimensionless specific-heat jump of △C/γnT = 0.98. The superconducting parameters of the critical magnetic fields, coherence length, penetration depth, and superconducting energy gap are given.ZiChen Liu BaiZhuo Li YuSen Xiao QingChen Duan YanWei Cui YuXue Mei Qian Tao ShuLi Wei ShuGang Tan Qiang Jing Qing Lu YuPing Sun YunYan Liu ShengGui Fu Hao Jiang Zhi Ren ZhuAn Xu Cao Wang GuangHan Cao 2021Science China(Physics,Mechanics & Astronomy)2021,64,7:1
12CENP-A的Ser68位动态磷酸化调控它在着丝粒区域的细胞周期依赖性装配显示文摘细胞出版社《发育细胞》创刊于2001年,本刊致力于搭建细胞生物学与发育生物学两大学科之间的桥梁。受过专业博士训l练的科学编辑与作者、审稿人、编委会成员共同合作,及时发布横跨两个领域令人振奋的研究成果,强调两个领域之间共同面临的问题以及相互之间的关系。该杂志2015年公布的影响因子为9.708。Zhouliang Yu Xiang Zhou Wenjing Wang Wenqiang Deng Junnan Fang Hao Hu Zichen Wang Shangze Li Lei Cui Jing Shen Linhui Zhai Shengyi Peng Jiemin Wong Shuo Dong Zengqiang Yuan Guangshuo Ou Xiaodong Zhang Ping Xu Jizhong Lou Na Yang Ping Chen Rui-Ming Xu 李国红 2016科学新闻2016,0,1:1
13Dynamic symmetry breaking and structure-preserving analysis on thelongitudinal wave in an elastic rod with a variable cross-section显示文摘The longitudinal wave propagating in an elastic rod with a variable cross-section owns wide engineering background,in which the longitudinal wave dissipation determines some important performances of the slender structure.To reproduce the longitudinal wave dissipation effects on an elastic rod with a variable cross-section,a structure-preserving approach is developed based on the dynamic symmetry breaking theory.For the dynamic model controlling the longitudinal wave propagating in the elastic rod with the variable cross-section,the approximate multi-symplectic form is deduced based on the multi-symplectic method,and the expression of the local energy dissipation for the longitudinal wave propagating in the rod is presented,referring to the dynamic symmetry breaking theory.A structure-preserving method focusing on the residual of the multi-symplectic structure and the local energy dissipation of the dynamic model is constructed by using the midpoint difference discrete method.The longitudinal wave propagating in an elastic rod fixed at one end is simulated,and the local/total energy dissipations of the longitudinal wave are investigated by the constructed structure-preserving scheme in two typical cases in detail.Jingjing HU Mengbo XU Weipeng HU Ruisong JIANG Zichen DENG 2022Applied Mathematics and Mechanics(English Edition)2022,43,1:0
14High-speed 2D beam steering based on a thin-film lithium niobate optical phased array with a large field of view显示文摘An on-chip optical phased array (OPA) is considered as a promising solution for next generation solid-state beam steering.However,most of the reported OPAs suffer from low operating bandwidths,making them limited in many applications.We propose and demonstrate a high-speed 2D scanning OPA based on thin-film lithium niobate phase modulators with traveling-wave electrodes.The measured modulation bandwidth is up to 2.5 GHz.Moreover,an aperiodic array combined with a slab grating antenna is also used to suppress the grating lobes of far-field beams,which enables a large field of view (FOV) as well as small beam width.A 16-channel OPA demonstrates an FOV of 50°×8.6°and a beam width of 0.73°×2.8°in the phase tuning direction and the wavelength scanning direction,respectively.WENLEI LI XU ZHAO JIANGHAO HE HAO YAN BINGCHENG PAN ZICHEN GUO XIANG’E HAN JINGYE CHEN DAOXIN DAI YAOCHENG SHI 2023Photonics Research2023,11,11:0
15Do methylenetetrahydrofolate dehydrogenase, cyclohydrolase, and formyltetrahydrofolate synthetase 1 polymorphisms modify changes in intelligence of school-age children in areas of endemic fluorosis?显示文摘Background: Excessive exposure to fluoride can reduce intelligence. Methylenetetrahydrofolate dehydrogenase, cyclohydrolase, and formyltetrahydrofolate synthetase 1 (MTHFD1) polymorphisms have important roles in neurodevelopment. However, the association ofMTHFD1 polymorphisms with children’s intelligence changes in endemic fluorosis areas has been rarely explored.Methods: A cross-sectional study was conducted in four randomly selected primary schools in Tongxu County, Henan Province, from April to May in 2017. A total of 694 children aged 8 to 12 years were included in the study with the recruitment by the cluster sampling method. Urinary fluoride (UF) and urinary creatinine were separately determined using the fluoride ion-selective electrode and creatinine assay kit. Children were classified as the high fluoride group and control group according to the median of urinary creatinine-adjusted urinary fluoride (UFCr) level. Four loci ofMTHFD1 were genotyped, and the Combined Raven’s Test was used to evaluate children’s intelligence quotient (IQ). Generalized linear model and multinomial logistic regression model were performed to analyze the associations between children’s UFCr level,MTHFD1 polymorphisms, and intelligence. The general linear model was used to explore the effects of gene-environment and gene-gene interaction on intelligence.Results: In the high fluoride group, children’s IQ scores decreased by 2.502 when the UFCr level increased by 1.0 mg/L (β= –2.502, 95% confidence interval [CI]: –4.411, –0.593), and the possibility for having 'excellent' intelligence decreased by 46.3% (odds ratio = 0.537, 95% CI: 0.290, 0.994). Children with the GG genotype showed increased IQ scores than those with the AA genotype of rs11627387 locus in the high fluoride group (P < 0.05). Interactions between fluoride exposure andMTHFD1 polymorphisms on intelligence were observed (Pinteraction < 0.05).Conclusion: Our findings suggest that excessive fluoride exposure may have adverse effects on children’s intelligence, and changes in children’s intelligence may be associated with the interaction between fluoride andMTHFD1 polymorphisms.Zichen Feng Ning An Fangfang Yu Jun Ma Na Li Yuhui Du Meng Guo Kaihong Xu Xiangbo Hou Zhiyuan Li Guoyu Zhou Yue Ba 2022Chinese Medical Journal2022,,15:0
16Research on the Reform of School-Enterprise Cooperation Teaching and Education Mode for Computer Majors显示文摘This paper discusses the innovative methods of school-enterprise cooperation education mode in computer applied talent training.An innovative training model based on school-enterprise cooperation is proposed to promote the cultivation of students’practical and innovative skills,so as to better adapt to the needs of society.By analyzing the key links and influencing factors of the training mode,this paper puts forward some concrete suggestions and measures to provide guidelines for universities and enterprises in personnel training.Zichen Xu 2024Journal of Contemporary Educational Research2024,8,2:0
17Erratum on “12-tungstophosphoric acid niched in Zr-BTC: a stable and efficient catalyst for Friedel-Crafts acylation” [Sci.China Chem., 2018, 61: 402–411]显示文摘Erratum to:Sci China Chem,2018,61:402-411,http://gffzzd3cc09b8251d45dfs6pnq0k59f5x569uv.ffgz.tsg.suse.edu.cn/10.1007/sll426-017-9182-0 For the above referenced publication[1],there is a correction in the Figure 9.Figure 9 Catalytic activity of pristine Zr-BTC(a),18.6 wt%HPW@Zr-BTC(b),25.2 wt%HPW@Zr-BTC(c).Latif Ullah Guoying Zhao Zichen Xu Hongyan He Muhammad Usman Suojiang Zhang 2021Science China Chemistry2021,64,8:0
18A PRECISE METHOD FOR SOLVING WAVE PROPAGATION IN HOLLOW SANDWICH CYLINDERS WITH PRISMATIC CORES显示文摘Wave propagation in infinitely long hollow sandwich cylinders with prismatic cores is analyzed by the extended Wittrick-Williams(W-W) algorithm and the precise integration method(PIM). The effective elastic constants of prismatic cellular materials are obtained by the homogenization method. By applying the variational principle and introducing the dual variables, the canonical equations of Hamiltonian system are constructed. Thereafter, the wave propagation problem is converted to an eigenvalue problem. In numerical examples, the effects of the prismatic cellular topology, the relative density, and the boundary conditions on dispersion relations,respectively, are investigated.Junmiao Meng Zichen Deng Xiao jian Xu Kai Zhang Xiuhui Hou 2015Acta Mechanica Solida Sinica2015,28,4:0
19Wuyi Mountain National Park:A Model of Ecological Conservation显示文摘Straddling Fujian and Jiangxi provinces,the Wuyi Mountain National Park covers 1,280 square kilometers.Among the first group of five national parks in China,it is the only one to be inscribed onto both the World Network of Biosphere Reserves and the World Cultural and Natural Heritage List.The national park has preserved the most complete and largest mid-subtropical primary forest ecosystem at its latitude in the world.Tian Xiao Xu Zichen 2024China Pictorial2024,,2:0
20Habenula,a potential central target for glucose metabolism in type 2 diabetes显示文摘The role of the habenular nucleus(Hb)in the pathogenesis of depression has been thoroughly studied,but whether it functions in the pathogenesis of diabetes remains unknown.In this study,type 2 diabetes(T2DM)rats,which induced by the high-carbohydrate and fat diet combined with STZ were employed.The functions of Hb were suppressed by application of electrical lesion.Compared with the sham group,the expression levels of AMPK phosphorylation and insulin receptor were significantly increased,whereas glucose-6-phosphatase and phosphoenolpyruvate carboxylated kinase was reduced,in the liver of the Hb lesions group.Qu Peng Wang Yachun Sun Yimeng Xu Zichen Yang Limin 2021解剖学杂志2021,44,S01:0
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