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508篇 您的检索式:作者名="Guozhen"
    题名 作者 年代 出处 被引量
1Dynamic mechanism and present situation of rural settlement evolution in China显示文摘这篇论文提供影响农村解决的进化的因素的详细分析,包括自然环境限制,基础结构,地区性的文化继承和集成,都市化和农村工业转变,陆地使用改革和革新,农村家庭行为变换,宏控制政策因素等等。在农村解决进化上基于效果的方法和度之间的差别,这些因素被分类进基本因素,新型的因素和变化因素。基本因素的开车主要集中于农村解决的传统的继承,新型的因素主要影响因素可以引起的农村解决转变,和变化突然的变化。所有这些因素为农村解决的进化组成三车轮的开车机制,并且塑造三条典型司机路径:慢在变化因素下面在基本因素,到在新型的因素下面的快速的开发的新路径,和突然的变化路径下面弄平路径。纸也在解决系统的方面调查农村解决进化的全面状况,解决规模,解决形态学,解决功能,解决文化,解决环境,等等。农村解决进化的一般过程被划分成四个阶段:起始、过渡、发展、成熟的阶段。ZHOU Guohua HE Yanhua TANG Chengli YU Tao XIAO Guozhen ZHONG Ting 2013Journal of Geographical Sciences2013,23,3:65
2New field of cryptography: DNA cryptography显示文摘DNA cryptography is a new born cryp- tographic field emerged with the research of DNA computing, in which DNA is used as information car- rier and the modern biological technology is used as implementation tool. The vast parallelism and ex- traordinary information density inherent in DNA molecules are explored for cryptographic purposes such as encryption, authentication, signature, and so on. In this paper, we briefly introduce the biological background of DNA cryptography and the principle of DNA computing, summarize the progress of DNA cryptographic research and several key problems, discuss the trend of DNA cryptography, and compare the status, security and application fields of DNA cryptography with those of traditional cryptography and quantum cryptography. It is pointed out that all the three kinds of cryptography have their own ad- vantages and disadvantages and complement each other in future practical application. The current main difficulties of DNA cryptography are the absence of effective secure theory and simple realizable method. The main goal of the research of DNA cryptography is exploring characteristics of DNA molecule and reac- tion, establishing corresponding theories, discovering possible development directions, searching for sim- ple methods of realizing DNA cryptography, and lay- ing the basis for future development.XIAO Guozhen LU Mingxin QIN Lei LAI Xuejia 2006Chinese Science Bulletin2006,51,12:16
3Technology and Experiments of 42CrMo Bearing Ring Forming Based on Casting Ring Blank显示文摘Bearing ring is the crucial component of bearing. With regard to such problems as material waste, low efficiency and high energy consumption in current process of producing large bearing ring, a new process named 'casting-rolling compound forming technology' is researched by taking the typical 42CrMo slew bearing as object. Through theoretical analysis, the design criteria of the main casting-rolling forming parameters are put forward at first. Then the constitutive relationship model of as-cast 42CrMo steel and its mathematical model of dynamic recrystallization are obtained according to the results of the hot compression experiment. By a coupled thermal-mechanical finite element model for radial-axial rolling of bearing ring, the fraction of dynamic recrystallization is calculated and recrystallized grains size are predicated. Meanwhile, the effects of the initial rolling temperature and feed rate of idle roll on material microstructure evolution are analyzed. Finally, the industrial rolling experiment is designed and performed, based on the simulation results. In addition, mechanical and metallographic tests are conducted on rolled bearing ring to get the mechanical parameters and metallographic structure. The experimental data and results show that the mechanical properties of bearing ring produced by casting-rolling compound forming technology are up to industrial standard, and a qualified bearing ring can be successfully formed by employing this new technology. Through the study, a process of forming large bearing ring directly by using casting ring blank is obtained, which could provide an effective theoretical guidance for manufacturing large ring parts. It also has an edge in saving material, lowering energy and improving efficiency.LI Yongtang JU Li QI Huiping ZHANG Feng CHEN Guozhen WANG Mingli 2014Chinese Journal of Mechanical Engineering2014,27,2:16
4Ultralong-life and high-rate web-like Li4Ti5O12 anode for high-performance flexible lithium-ion batteries显示文摘Xianfu Wang Bin Liu Xiaojuan Hou Qiufan Wang Wenwu Li Di Chen Guozhen Shen 2014Nano Research2014,7,7:16
5Root–shoot competition interactions cause diversity loss after fertilization:a field experiment in an alpine meadow on the Tibetan Plateau显示文摘Aims A decrease in species diversity after fertilization is a common phenomenon in grasslands;however,the mechanism causing it remains highly controversial.The light competition hypothesis to explain loss of diversity has received much attention.The aim of the present paper was to test this hypothesis.Methods Fertilization was used to control above-and belowground resources simultaneously,while shade was used to control aboveground resource in an alpine meadow on the Tibetan Plateau.Univariate general linear models was used to estimate the effects of fertilization and shade on above-and belowground vegetation characteristics,including photosynthetically active radiation(PAR)in the understory,aboveground biomass,belowground biomass,R:S ratio,species richness and Simpson’s diversity index.Important findings PAR was similar in the understory of shaded and fertilized plots,but only fertilization reduced species richness and diversity,suggesting that light competition alone could not explain diversity loss after fertilization.The root biomass and R:S ratio had a significant increase in shaded plots,but the richness and diversity did not change,suggesting that root competition alone also could not explain diversity loss after fertilization in this community.Our results illustrated that the root–shoot competition interactions,investigated from a functional groups perspective,should be the most reasonable explanation leading to the diversity loss due to fertilization.Wei Li Shujun Wen Wenxiang Hu Guozhen Du 2011Journal of Plant Ecology2011,4,3:15
6High-detectivity InAs nanowire photodetectors with spectral response from ultraviolet to near-infrared显示文摘InAs 是直接、狭窄的乐队差距(0.354 eV ) 材料与超离频电子活动性,并且潜在地在宽 UV-visible-near-infrared 区域的一个好 optoelectronic 设备候选人。在这个工作,我们报导 InAs 基于 nanowire 的光电探测器的制造,它在一个女人上显示出很高的 photoresponse 光谱从 300 ~ 1,100 nm 的范围。responsivity,外部量效率和设备的 detectivity 分别地被测量是有用在一台原子力量显微镜(AFM ) 之间产生的高静电的地的 nanoscopic 精确的 4.4 张 y 还原剂 graphene 氟化物(GF ) 表尖端和 GF 底层。由电场的氟的符号的减小急速地与表抵抗力与 105-1,800 nm 的宽度生产 graphene nanoribbons (GNR ) 减少了从 > 1 T ????????  ?  ?Zhe Liu Tao Luo Bo Liang Gui Chen Gang Yu Xuming Xie Di Chen Guozhen Shen 2013Nano Research2013,6,11:12
7Fabrication of flexible reduced graphene oxide/Fe2O3 hollow nanospheres based on-chip micro-supercapacitors for integrated photodetecting applications显示文摘因为他们的唯一、有益的设计,同样重要的在薄片上 micropower 采购的 Micro-supercapacitors (MSC ) 在使小型化的便携式的电子设备应用程序在一块最小化的大小的芯片和优秀机械灵活性 / 稳定性以内为优化最大的功能吸引了可观的注意。在这个工作,我们基于减少的 graphene oxide/Fe 2 用一种 microelectronic 影印石版术技术的空 nanospheres 与血浆蚀刻相结合的 O 3 技术。为在薄片上 MSC 的唯一的结构的设计启用高效的改进与相比 graphene 仅仅设备,展出 11.57 F 潮慣慴祬瑳 ? 湩琠敨爠摥 ' 讟 N 湯漠 ? 的高特定的电容 ? 楮牴灯敨潮 ? 琠敨爠慥瑣潩 ? 慲整挠敯晦捩敩瑮眠獡 ? 金 ? 湡 ??? 楴敭 ? 楨桧牥琠慨 ? 桴瑡漠 ? 桴 ? 潧摬渭湡牯摯 ? 湡 ? 慣敧 ? 潧摬渭湡牯摯 ' 嬑垴窊瓲創瓛讟 N 湯 ? 景 ? 渭瑩潲桰湥汯? 敲灳 ' 虡 NShaosong Gu Zheng Lou Ludong Li Zhaojun Chen Xiangdong Ma Guozhen Shen 2016Nano Research2016,9,2:12
8Advanced rechargeable lithium-ion batteries based on bendable ZnCo2O4-urchins-on-carbon-fibers electrodes显示文摘ZnCo2O4-urchins-on-carbon-fibers 矩阵的一个新奇的班被设计了,描绘,并且过去常制作高效的精力存储设备。我们获得了 1180 妈数慲畴敲 ?L 癯 ? ㈱? 的一个可逆的锂存储能力 ?? 牣慥楳杮倠 ? 挠湯整瑮 ?? 桳牯 ? 整浲 ??? 琠敨浲污琠敲瑡敭瑮 ? 瑡 ??? 鲖 ? 栀氠睯牥愠摮甠灰牥焠慵瑮汩獥映牯搠楡祬洠湩浩浵琠浥数爔?爔 吗??Bin Liu Xianfu Wang Boyang Liu Qiufan Wang Dongsheng Tan Weifeng Song Xiaojuan Hou Di Chen Guozhen Shen 2013Nano Research2013,6,7:10
9A computational cognition model of perception,memory,and judgment显示文摘The mechanism of human cognition and its computability provide an important theoretical foundation to intelligent computation of visual media.This paper focuses on the intelligent processing of massive data of visual media and its corresponding processes of perception,memory,and judgment in cognition.In particular,both the human cognitive mechanism and cognitive computability of visual media are investigated in this paper at the following three levels:neurophysiology,cognitive psychology,and computational modeling.A computational cognition model of Perception,Memory,and Judgment(PMJ model for short)is proposed,which consists of three stages and three pathways by integrating the cognitive mechanism and computability aspects in a unified framework.Finally,this paper illustrates the applications of the proposed PMJ model in five visual media research areas.As demonstrated by these applications,the PMJ model sheds some light on the intelligent processing of visual media,and it would be innovative for researchers to apply human cognitive mechanism to computer science.FU XiaoLan CAI LianHong LIU Ye JIA Jia CHEN WenFeng YI Zhang ZHAO GuoZhen LIU YongJin WU ChangXu 2014Science China(Information Sciences)2014,57,3:10
10Transformation of human amniotic epithelial cells into neuron-like cells in the microenvironment of traumatic brain injury in vivo and in vitro显示文摘Survival and differentiation of transplanted cells is closely related to the local microenvironment.The present study cultured human amniotic epithelial cells(HAECs) in a simulated microenvironment in vitro comprising RPMI 1640 culture medium and the solution extracted from injured brain tissues.Some HAECs were round,triangular in form or irregularly shaped,with extended neuron-like processes;some of the processes were interconnected,representing neuron-like morphology and some HAECs were microtubule-associated protein 2-positive.HAECs survived for at least 4 weeks following transplantation into the center and edges of the trauma focus with traumatic brain injury,and were microtubule-associated protein 2-positive.Moreover,the motor function of rat hind limbs was significantly improved.Yi Lu Guozhen Hui Zhiyuan Wu Tianjin Liu Xunhe Ji Lihe Guo 2011Neural Regeneration Research2011,6,10:10
11Joint User Scheduling and Antenna Selection in Distributed Massive MIMO Systems with Limited Backhaul Capacity显示文摘Massive MIMO systems offer a high spatial resolution that can drastically increase the spectral and/or energy efficiency by employing a large number of antennas at the base station(BS).In a distributed massive MIMO system,the capacity of fiber backhaul that links base station and remote radio heads is usually limited,which becomes a bottleneck for realizing the potential performance gain of both downlink and uplink.To solve this problem,we propose a joint antenna selection and user scheduling which is able to achieve a large portion of the potential gain provided by the massive MIMO array with only limited backhaul capacity.Three sub-optimal iterative algorithms with the objective of sumrate maximization are proposed for the joint optimization of antenna selection and user scheduling,either based on greedy fashion or Frobenius-norm criteria.Convergence and complexity analysis are presented for the algorithms.The provided Monte Carlo simulations show that,one of our algorithms achieves a good tradeoff between complexity and performance and thus is especially fit for massive MIMO systems.XU Guozhen LIU An JIANG Wei XIANG Haige LUO Wu 2014China Communications2014,11,5:9
12Polynomials,Higher Order Sobolev Extension Theorems and Interpolation Inequalities on Weighted Folland-Stein Spaces on Stratified GroupsGuozhen Lu Department of Mathematics,Wayne State University,Detroit,MI 48202,USA 2000Acta Mathematica Sinica,English Series2000,16,3:9
13Quadrilateral isoparametric finite elements for plane elastic Cosserat bodies显示文摘4-node, 8-node and 8(4)-node quadrilateral plane isoparametric elements are used for the solution of bound ary value problems in linear isotropic Cosserat elasticity. The patch test is applied to validate the finite elements. Engineering problems of stress concentration around a circular hole in plane strain condition and mechanical behaviors of heterogeneous materials with rigid inclusions and pores are computed to test the accuracy and capability of these three types of finite elements.Hongwu Zhang Hui Wang Guozhen Liu 2005Acta Mechanica Sinica2005,21,4:8
14Brain-derived neurotrophic factor induces neuron-like cellular differentiation of mesenchymal stem cells derived from human umbilical cord blood cells in vitro显示文摘Human umbilical cord blood was collected from full-term deliveries scheduled for cesarean section.Mononuclear cells were isolated,amplified and induced as mesenchymal stem cells.Isolated mesenchymal stem cells tested positive for the marker CD29,CD44 and CD105 and negative for typical hematopoietic and endothelial markers.Following treatment with neural induction medium containing brain-derived neurotrophic factor for 7 days,the adherent cells exhibited neuron-like cellular morphology.Immunohistochemical staining and reverse transcription-PCR revealed that the induced mesenchymal stem cells expressed the markers for neuron-specific enolase and neurofilament.The results demonstrated that human umbilical cord blood-derived mesenchymal stem cells can differentiate into neuron-like cells induced by brain-derived neurotrophic factor in vitro.Lei Chen Zhongguo Zhang Bing Chen Xiaozhi Liu Zhenlin Liu Hongliang Liu Gang Li Zhiguo Su Junfei Wang Guozhen Hui 2011Neural Regeneration Research2011,6,13:8
15Roadway deformation during riding mining in soft rock显示文摘'Riding mining' is a form of mining where the working face is located above the roadway and advances parallel to it.Riding mining in deep soft rock creates a particular set of problems in the roadway that include high stresses,large deformations,and support difficulties.Herein we describe a study of the rock deformation mechanism of a roadway as observed during riding mining in deep soft rock.Theoretical analysis,numerical simulations,and on site monitoring were used to examine this problem.The stress in the rock and the visco-elastic behavior of the rock are considered.Real time data,recorded over a period of 240 days,were taken from a 750 transportation roadway.Stress distributions in the rock surrounding the roadway were studied by comparing simulations to observations from the mine.The rock stress shows dynamic behavior as the working face advances.The pressure increases and then drops after peaking as the face advances.Both elastic and plastic deformation of the surrounding rock occurs.Plastic deformation provides a mechanism by which stress in the rock relaxes due to material flow.A way to rehabilitate the roadway is suggested that will help ensure mine safety.Zhao Guozhen Ma Zhanguo Zhu Qinghua Mao Xianbiao Feng Meimei 2012International Journal of Mining Science and Technology2012,22,4:7
16A User-Centric Data Secure Creation Scheme in Cloud Computing显示文摘Due to the use of the cloud computing technology,the ownership is separated from the administration of the data in cloud and the shared data might be migrated between different clouds,which would bring new challenges to data secure creation,especially for the data privacy protection.We propose a User-centric data secure creation scheme(UCDSC) for the security requirements of resource owners in cloud.In this scheme,a data owner first divides the users into different domains.The data owner encrypts data and defines different secure managing policies for the data according to domains.To encrypt the data in UCDSC,we present an algorithm based on Access control conditions proxy re-encryption(ACC-PRE),which is proved to be master secret secure and Chosen-ciphertext attack(CCA) secure in random oracle model.We give the application protocols and make the comparisons between some existing approaches and UCDSC.SU Mang LI Fenghua SHI Guozhen GENG Kui XIONG Jinbo 2016Chinese Journal of Electronics2016,25,4:7
17Construction of almost optimal resilient Boolean functions via concatenating Maiorana-McFarland functions显示文摘We describe a method to construct an n-variable (n even) almost optimal resilient Boolean function via concatenating 2 d properly chosen (n-d)-variable Maiorana-McFarland functions.As an example,a 5-resilient 42-variable Boolean function with currently best known nonlinearity 2 41-2 20-2 17 is provided.ZHANG WeiGuo XIAO GuoZhen 2011Science China(Information Sciences)2011,54,4:7
18comLinking flowering and reproductive allocation in response to nitrogen addition in an alpine meadow显示文摘Aims Plants can change in phenology and biomass allocation in response to environmental change.It has been demonstrated that nitrogen is the most limiting resource for plants in many terrestrial ecosystems.Previous studies have usually focused on either flowering phenology or biomass allocation of plants in response to nitrogen addition;how-ever,attempts to link flowering phenology and biomass allocation are still rare.In this study,we tested the effects of nitrogen addition on both flowering phenology and reproductive allocation in 34 common species.We also examined the potential linkage between flowering time and reproductive allocation in response to nitrogen addition.Methods We conducted a 3-year nitrogen addition experiment in Tibetan alpine meadow.We measured first flowering date and the repro-ductive allocation for 34 common plant species in control,low and high nitrogen added plots,respectively.one-way analysis of variance was used to examine differences of first flowering date and reproductive allocation among treatments.The relationships between the change in species first flowering date and change in reproductive allocation in response to nitrogen addition were examined by calculating Pearson correlation coefficients.Important Findings For most species,both first flowering date and reproductive alloca-tion significantly responded to nitrogen addition.Nitrogen addition significantly delayed the first flowering date and reduced the repro-ductive allocation for all graminoid species,but accelerated flower-ing and increased reproductive allocation for most forb species.We found that changes in first flowering date significantly negatively correlated with the changes in reproductive allocation over spe-cies in response to nitrogen,which indicated a positive relationship between flowering response and plant performance in reproductive allocation.species that advanced their flowering time with nitrogen addition increased their reproductive allocation,whereas those that delayed flowering time tended to decline in reproductive allocation with nitrogen addition.our results suggest that species-specific switch from vegetative growth to reproductive growth could influence species performance.Zhilong Zhang Kechang Niu Xudong Liu Peng Jia Guozhen Du 2014Journal of Plant Ecology2014,7,3:7
19Mechanical properties and enhancement mechanisms of titanium-graphene nanocomposites显示文摘Molecular dynamics(MD)simulations of the titanium-graphene nanocomposites(TiGNCs)under uniaxial tension are carried out to investigate the mechanical properties and reinforcement mechanism of graphene in composites.It is found that introduction of mechanically robust graphene limits the strain-induced dislocation and araorphization and thereby highly improves the mechanical properties of metallic titanium that are greatly affected by the crystal stacking orientation of graphene and titanium layers.The thickness of titanium layers,interface interaction and working temperature play an important role in the mechanical strength and elastic moduli of composites.The results show the mechanical properties of TiGNCs are monotonically enhanced with reduction of the titanium layer thickness and working temperature,and the Young5s modulus obtained by MD simulation are higher than that predicted by the rule of mixture(ROM)due to consideration of interfacial interaction in computational calculation.In addition,once the critical thickness of titanium layer is reached,graphene wrinkles are induced in composites because of Poisson's effect induced large lateral compression stress in the interface region.This study provides helpful insights into fundamental understanding reinforcing mechanism of graphene and ultimately contribute to the optimal design and performance of mechanically robust graphene-based metallic composites.Wanhong Tang Jie Zhang Jianyang Wu Jinyou Shao Peng Ding Guozhen Hou Xiaoming Chen 2020Acta Mechanica Sinica2020,36,4:7
20Recent advances in low-dimensional semiconductor nanomaterials and their applications in high-performance photodetectors显示文摘Low-dimensional(including two-dimensional[2D],one-dimensional[1D],and zero-dimensional[0D])semiconductor materials have great potential in electronic/optoelectronic applications due to their unique structure and characteristics.Many 2D(such as transition metal dichalcogenides and black phosphorus)and 1D(such as NWs)materials have demonstrated superior performance in field effect transistors,photodetectors(PDs),and some flexible devices.And in some hybrid structures of 0D materials and 1D or 2D materials,the modification of 1D and 2D devices by 0D materials is embodied.This type of hybrid heterostructure has a larger performance optimization compared with the original.In the application of PDs,the variety of lowdimensional materials and properties enable wide-spectrum detection from ultraviolet UV to infrared,which provide a potential option for PDs under various conditions.For flexible electronic devices,high performance and mechanical stability are two important features.Low-dimensional materials offer unparalleled advantages in flexible devices.In this review,we will focus on the various low-dimensional materials that have been extensively studied and their applications in the electronics/optoelectronic and flexible electronics.From the composition and lattice structure of materials(including alloys)to the construction of various devices and heterostructures,we will introduce their application and recent development under various conditions.These works can provide valuable guidance for the construction and application of more highperformance and multifunctional devices.Jingzhi Fang Ziqi Zhou Mengqi Xiao Zheng Lou Zhongming Wei Guozhen Shen 2020InfoMat2020,2,2:7
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