检索结果-南通市图书馆

Structural characteristics,dispersion,and modification of fibrous brucite

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2014年第1期21卷 82-88页

作者： xi cao xiu-yun Chuan Key Laboratory of Orogen and Crust Evolution of the Education Ministry of China School of Earth and Space SciencesPeking University

Fibrous bmcite has very unique structure and physical properties. Brucite fibers were exfoliated into single nanofibers by using dioctyl sodium sulfosuccinate （AOT） as a dispersant through mechanical agitation and ultrasonic dispersion; and then, the nanofibers were modified by stearic acid and （3-aminopropyl）triethoxysilane （y-APS） compound modification agent. The nanofibers were characterized by using X-ray diffraction （XRD）, scanning electron microscopy （SEM）, transmission electron microscopy （TEM）, Fourier transform infrared spectroscopy （FTIR）, and thermal gravimetric analysis. It is found that AOT has good effect on the dispersion. The single fiber has a consis- tent morphology, and fibrous bmcite is dispersed and modified without destroying the crystal structure. Infrared and thermal analysis shows that the surface modification of fibrous brucite is achieved by forming chemical bonds between the coupling agent and magnesium hydroxide.

关键词： fibrous brucite dispersion nanofibers surface treatment modification

An Idealized Numerical Study of the Effects of Uniform Zonal Winds on Tropical Cyclogenesis

在线全文

学校读者我要写书评

暂无评论

Atmospheric and Oceanic Science Letters 2015年第6期8卷 345-351页

作者： cao xi Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences

The effect of uniform zonal winds on tropical cyclone(TC)genesis is examined on a beta plane using an idealized mesoscale *** simulation results show that uniform easterly and westerly flows are both favorable for TC ***,uniform easterly flows result in a faster TC genesis rate compared with uniform westerly *** is found that faster TC genesis is associated with greater surface heat fluxes and convection during the early *** superposition of uniform easterly flows and the beta effect results in greater surface heat fluxes and convection around the TC center compared with uniform westerly ***,TC genesis is closely associated with the size and intensity of a mid-level *** joint greater convection induced by the easterly flows and beta effect results in enhancement of the vertical temperature gradient,which is associated with the intensification of mid-level *** strong and compact mid-level circulation is more favorable for efficient conversion of latent heat energy to the kinetic energy of the lower-level cyclonic ***,uniform easterly flows are more favorable for TC genesis than uniform westerly flows.

关键词： uniform zonal winds tropical cyclogenesis idealize

A New Pathway for Senescence Regulation

在线全文

学校读者我要写书评

暂无评论

Genomics, Proteomics & Bioinformatics 2015年第6期13卷 333-335页

作者： xi cao Mo Li School of Basic Medical Sciences Peking University Health Science Center Center for Reproductive Medicine Peking University Third Hospital

Research concerning senescence has become a hotspot since the conception of ＇cellular senescence＇ was put forward by Drs. Hayflick and Moorhead over five decades ago [1]. Recently, a paper published in Science by Kang and colleagues, which this article aims to comment on, provides evidence of a new pathway involved in senescence [2]. Senescence is a physiological and pathological process induced by numerous factors, during which cell growth ceases and gene expression alters. As can be imagined, such state protects against the development of cancer and plays an important role in tissue repair [3]. On the other hand, senescence is involved in many other processes such as aging and neurodegenerative disease [4-6]. Recent studies show that senescent cells produce senescence-associated secretory phenotype （SASP） factors including chemokines, proteases,

关键词： GATA cell SASP DDR cycle

Coupled Cross-Flow/in-Line Vortex-Induced Vibration Responses of a Catenary-Type Riser Subjected to Uniform Flows

在线全文

学校读者我要写书评

暂无评论

Journal of Ocean University of China 2024年第5期23卷 1202-1212页

作者： LI xiaomin cao xi LI Fuheng YANG Zhiwen College of Engineering Ocean University of ChinaQingdao 266404China College of Hydrodynamic Engineering Tianjin Research Institute for Water Transport EngineeringM.O.TTianjin 300456China

A three-dimensional numerical scheme was developed to investigate the vortex-induced vibration(VIV)of a catenary-type riser(CTR)in the in-line(IL)and cross-flow(CF)*** using the vector form intrinsic finite element method,the CTR was discretized into a finite number of spatial particles whose motions satisfy Newton’s second *** Van der Pol oscillator was used to simulate the effect of vortex *** coupling equations of structural vibration and wake oscillator were solved using an explicit central differential *** numerical model was verified with the published *** VIV characteristics of the CTR subjected to uniform flows,including displacement,frequency,standing wave,traveling wave,motion trajectory,and energy transfer,were studied *** numerical results revealed that the multimode property occurs in the CF-and IL-direction VIV responses of the *** increase in the flow velocity has slight effects on the maximum VIV *** to structural nonlin-earity,the double-frequency relationship in the CF and IL directions is rarely ***,the vibration trajectories display the shape of an inclined elliptical ***,the negative energy region is inconspicuous under the excitation of the uniform flow.

关键词： vortex-induced vibration vector form intrinsic finite element catenary-type riser wake oscillator equation

Intensified Impact of Northern Tropical Atlantic SST on Tropical Cyclogenesis Frequency over the Western North Pacific after the Late 1980s

在线全文

学校读者我要写书评

暂无评论

Advances in Atmospheric Sciences 2016年第8期33卷 919-930页

作者： xi cao Shangfeng CHEN Guanghua CHEN Renguang WU Center for Monsoon System Research Institute of Atmospheric Physics Chinese Academy of Sciences State Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics Institute of Atmospheric Physics Chinese Academy of Sciences

Previous studies suggest that spring SST anomalies over the northern tropical Atlantic（NTA） affect the tropical cyclone（TC） activity over the western North Pacific（WNP） in the following summer and fall. The present study reveals that the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is not stationary. The influence of spring NTA SST on following summer–fall WNP TC genesis frequency is weak and insignificant before, but strong and significant after, the late 1980 s. Before the late 1980 s, the NTA SST anomaly-induced SST anomalies in the tropical central Pacific are weak, and the response of atmospheric circulation over the WNP is not strong. As a result, the connection between spring NTA SST and following summer–fall WNP TC genesis frequency is insignificant in the former period. In contrast,after the late 1980 s, NTA SST anomalies induce pronounced tropical central Pacific SST anomalies through an Atlantic–Pacific teleconnection. Tropical central Pacific SST anomalies further induce favorable conditions for WNP TC genesis,including vertical motion, mid-level relative humidity, and vertical zonal wind shear. Hence, the connection between NTA SST and WNP TC genesis frequency is significant in the recent period. Further analysis shows that the interdecadal change in the connection between spring NTA SST and following summer–fall WNP TC genesis frequency may be related to the climatological SST change over the NTA region.

关键词： northern tropical Atlantic SST tropical cyclone western North Pacific

Optimization of Air Route Network Nodes to Avoid ″Three Areas″ Based on An Adaptive Ant Colony Algorithm

在线全文

学校读者我要写书评

暂无评论

Transactions of Nanjing University of Aeronautics and Astronautics 2016年第4期33卷 469-478页

作者： Wang Shijin Li Qingyun cao xi Li Haiyun College of Civil Aviation Nanjing University of Aeronautics and Astronautics

Air route network(ARN)planning is an efficient way to alleviate civil aviation flight delays caused by increasing development and pressure for safe ***,the ARN shortest path was taken as the objective function,and an air route network node(ARNN)optimization model was developed to circumvent the restrictions imposed by″three areas″,also known as prohibited areas,restricted areas,and dangerous areas(PRDs),by creating agrid *** finally the objective function was solved by means of an adaptive ant colony algorithm(AACA).The A593,A470,B221,and G204 air routes in the busy ZSHA flight information region,where the airspace includes areas with different levels of PRDs,were taken as an *** on current flight patterns,a layout optimization of the ARNN was computed using this model and algorithm and successfully avoided *** optimized result reduced the total length of routes by 2.14% and the total cost by 9.875%.

关键词： air route network planning three area avoidance optimization of air route network node adaptive ant colony algorithm grid environment

HAPE3D—a new constructive algorithm for the 3D irregular packing problem

在线全文

学校读者我要写书评

暂无评论

Frontiers of Information Technology & Electronic Engineering 2015年第5期16卷 380-390页

作者： xiao LIU Jia-min LIU An-xi cao Zhuang-le YAO School of Civil and Transportation Engineering South China University of Technology School of Information Science and Engineering Shenyang University of Technology College of Ocean Science and Engineer Shanghai Maritime University

We propose a new constructive algorithm, called HAPE3 D, which is a heuristic algorithm based on the principle of minimum total potential energy for the 3D irregular packing problem, involving packing a set of irregularly shaped polyhedrons into a box-shaped container with fixed width and length but unconstrained height. The objective is to allocate all the polyhedrons in the container, and thus minimize the waste or maximize profit. HAPE3 D can deal with arbitrarily shaped polyhedrons, which can be rotated around each coordinate axis at different angles. The most outstanding merit is that HAPE3 D does not need to calculate no-fit polyhedron(NFP), which is a huge obstacle for the 3D packing problem. HAPE3 D can also be hybridized with a meta-heuristic algorithm such as simulated annealing. Two groups of computational experiments demonstrate the good performance of HAPE3 D and prove that it can be hybridized quite well with a meta-heuristic algorithm to further improve the packing quality.

关键词： 3D packing problem Layout design Simulation Optimization Constructive algorithm Meta-heuristics

Effect of volume fraction and mechanical stability of austenite on ductility of medium Mn steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2019年第11期26卷 1209-1218页

作者： Si-lian Che Zhao-xi cao Chang Wang Chong-xiang Huang Dirk Ponge Wen-quan cao Central Iron and Steel Research Institute(CISRI) Beijing 100081China Science Faculty University of SydneySydney NSW 2006Australia School of Aeronautics and Astronautics Sichuan UniversityChengdu 610065SichuanChina Max-Planck-Institute for Iron Research Duesseldorf 40237Germany

A hot-rolled medium Mn(0.2C5Mn)steel is annealed at 650℃ to produce an ultrafine-grained duplex microstructure with different austenite volume fractions by austenite reverted transformation(ART)annealing,and the orientation relationship strictly obeys K-S orientation relationship before *** tests are carried out in a temperature range from-196 to 400℃ to examine the effects of the austenite volume fraction and the deformation temperature on the tensile properties and the austenite *** observations reveal that the metastable austenite gradually transformed into a-martensite,which is controlled by the deformation strain,the temperature and the austenite volume *** strain hardening behavior and ductility of the studied steel are dependent on austenite volume fraction and deformation temperature *** stress-strain curves of ART-annealed 0.2C5Mn steel assume an S shape and a very large work hardening rate of about 10 GPa is obtained at liquid nitrogen deformation *** on the experimental data,a quantitative relation is proposed to describe the ductility dependence on both the austenite volume fraction and its mechanical stability.

关键词： TRIP effect Ductility Phase transformation Austenite volume fraction Mechanical stability

Research of influence of the additional electrode on Hall thruster plume by particle-in-cell simulation

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 Physics B 2020年第9期29卷 377-383页

作者： xi-Feng cao Hui Liu Da-Ren Yu Laboratory of Plasma Propulsion Harbin Institute of TechnologyHarbin 150001China

Hall thruster is an electric propulsion device for attitude control and position maintenance of *** discharge process of Hall thruster will produce divergent *** plume will cause erosion,static electricity,and other interference to the main components,such as solar sailboard,satellite body,and ***,reducing the divergence of the plume is an important content in the research of thruster *** additional electrode to the plume area is a way to reduce the divergence angle of the plume,but there are few related *** paper uses the particle-in-cell(PIC)simulation method to simulate the effect of the additional electrode on the discharge of the Hall thruster,and further explains the effect mechanism of the additional electrode on parameters such as the electric field and plume divergence *** simulation results show that the existence of the additional electrode can enhance the potential near the additional *** increase of the potential can effectively suppress the radial diffusion of ions,and effectively reduce the plume divergence *** simulation results show that when the additional electrode is 30 V,the half plume divergence angle can be reduced by 18.21%.However,the existence of additional electric electrode can also enhance the ion bombardment on the magnetic *** additional electrode is relatively outside,the plume divergence angle is relatively small,and it can avoid excessive ion bombardment on the magnetic *** research work of this paper can provide a reference for the beam design of Hall thruster.

关键词： Hall thruster additional electrode plume divergence