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CFD-DEM simulation of spouting of corn-shaped particles

Particuology 2012年第5期10卷 562-572页

作者： Bing Ren Wenqi zhong Yu Chen xi Chen Baosheng Jin Zhulin Yuan Yong lu Ministry of Education of Key Laboratory of Energy Thermal Conversion and Control School of Energy and EnvironmentSoutheast UniversityNanjing210096China

Three dimensionally coupled computational fluid dynamics （CFD） and discrete element method （DEM） were used to investigate the flow of corn-shaped particles in a cylindrical spouted bed with a conical base. The particle motion was modeled by the DEM, and the gas motion by the k-ε two-equation turbulent model. A two-way coupling numerical iterative scheme was used to incorporate the effects of gas-particle interactions in terms of momentum exchange. The corn-shaped particles were constructed by a multisphere method. Drag force, contact force, Saffman lift force, Magnus lift force, and gravitational force acting on each individual particle were considered in establishing the mathematical modeling. Calculations were carried out in a cylindrical spouted bed with an inside diameter of 200 mm, a height of 700 mm, and a conical base of 60°. Comparison of simulations with experiments showed the availability of the multi-sphere method in simulating spouting action with corn-shaped particles, but it depended strongly on the number and the arrangement of the spherical elements. Gas-solid flow patterns, pressure drop, particle velocity and particle concentration at various spouting gas velocity were discussed. The results showed that particle velocity reaches a maximum at the axis and then decreases gradually along the radial direction in the whole bed. Particle concentration increases along the radial direction in the spout region but decreases in the fountain region, while it is nearly constant in the annulus region. Increasing spouting gas velocity leads to larger pressure drop, remarkably increased speed of particle moving upward or downward, but decreased particle concentration.

关键词： Gas-solid flowDiscrete element methodSpouted bedCorn-shaped particleMulti-sphere method

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Decontamination Efficacy of Disinfection and Doffing of Medical Protective Clothing:A Combined Mannequin and Personnel Study

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Biomedical and Environmental Sciences 2023年第11期36卷 1105-1109页

作者： xiE zhong Yi lu Long xi LI Ye FAN Ling Feng YANG Fan Fan lu Ye Department of Environmental Health Zhejiang Provincial Center for Disease Control and PreventionHangzhou 310000ZhejiangChina Zhejiang TAILIN Bioengineering Company Limited Hangzhou 310000ZhejiangChina Department of Microorganism Examination Ningbo Center for Disease Control and PreventionNingbo 315000ZhejiangChina

Personal protective equipment(PPE)plays a key role in protecting healthcare workers(HCWs)from highly infectious *** use of PPE based on the level of exposure can prevent severe acute respiratory syndrome coronavirus 2... 详细信息

关键词： protective acute respiratory

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Dynamic recrystallization behavior and strengthening mechanism of a novel Mo-Ti_(3)AlC_(2) alloy at ultrahigh temperature

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Rare Metals 2024年第8期43卷 3946-3960页

作者： lu Yang xin-Yuan Zheng Yang Zhao xi-Ran Wang Fang-Nao xiao Shi-zhong Wei School of Materials Science and Engineering Henan University of Science and TechnologyLuoyang 471023China National Joint Engineering Research Center for Abrasion Control and Molding of Metal Materials Henan University of Science and TechnologyLuoyang 471003China Department of Applied Mechanics Univ.Bourgogne FrancheComteFEMTO-ST InstituteCNRS/UF/ENSMM/UTBM25000BesangonFrance

Increasing the recrystallization temperature to achieve better high-temperature performance is critical in the development of molybdenum alloys for ultrahightemperature applications,such as the newest generation of multitype high-temperature nuclear *** this study,an innovative strategy was proposed to improve the performance of molybdenum alloys at high temperature by using the two-dimensional MAX(where M is an early transition metal,A is an A-group element and X is C or N)ceramic material Ti_(3)AlC_(2).The relationships between flow stress,strain rate and temperature were *** microstructure,distribution of misorientation and evolution of dislocations in the Mo-Ti_(3)AlC_(2) alloy were *** microscopic mechanism of the Ti_(3)AlC_(2) phase in the molybdenum alloy at high temperatures was *** experimental results showed that the peak flow stress of Mo-Ti_(3)AlC_(2) at 1600℃ reached 155 MPa,which was161.8% greater than that of pure *** activation energy of thermal deformation of Mo-Ti_(3)AlC_(2) was as large as537 kJ·mol~(-1),which was 17.6% more than that of pure *** recrystallization temperature reached 1600℃ or even *** topological reaction of the Ti_(3)AlC_(2) phase consumed a large amount of energy at high temperatures,resulting in increases in the deformation activation *** structures of AlTi_3 and Ti-O Magneli-phase oxides(Ti_nO_(2n-1)) were formed in-situ,which relied on kink bands and interlayer slip,resulting in many dislocations during ***,the special two-dimensional of the structure Ti_(3)AlC_(2) ceramic inhibited the recrystallization behavior of the Mo *** results of this study can provide theoretical guidance for the development of a new generation of molybdenum alloys for use in ultrahigh-temperature environments.

关键词： Mo alloy Two-dimensional reinforcement Dynamic recrystallization behavior Hot deformation Mechanical properties

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A study on the surface overpressure distribution and formation of a double curvature liner under a two-point initiation

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Defence Technology（防务技术） 2022年第1期18卷 148-157页

作者： Jie Liu xi Chen zhong-hua Du Nanging Vocational University of Industry Technology Nanjing210023China Nanjing University of Science and Technology Nanjing.210094China

The formation mechanism of an EFP(explosively formed projectile)using a double curvature liner under the overpressure effect generated by a regular oblique reflection was investigated in this *** on the detonation wave propagation theory,the change of the incident angle of the detonation wave collision at different positions and the distribution area of the overpressure on the surface of the liner were *** dimensional numerical simulations of the formation process of the EFP with *** well as the ability to penetrate 45#steel were performed using LS-DYNA software,and the EFP ve locity,the penetration ability,and the forming were assessed via experiments and x_ray *** experimental results coincides with those of the *** indicate that the collision of the detonation wave was controlled to be a regular oblique reflection acting on the liner by setting the di-mensions of the unit charge and maintai ning the pressure at the collision point region at more than 2.4 times the CJ detonation when the incident angle approached the cnitical *** distance from the liner midline to the boundary of the area within which the pressure ratio of the regular oblique reflection pressure to the qJ detonation pressure was greater than 2.5,2,and 15was approximately 0.66 mm,132 mm,and 3.3 mm,*** noted that pressure gradient caused the liner to turn inside out in the middle to form the head of the EFP and close the two tails of the EFP at approximately 120μ*** penetration depth of the EFP into a 45#steel target exceeded 30 mm,and there was radial expansion between the head and tail of the EFP,increasing the penetration resistance of the ***,the structural size of the unit charge and the liner can be further optimized to reduce resist ance to increase the penetration ability of the EFP.

关键词： Unit-shaped charge Double curvature liner Regular oblique reflection Two-point initiation Pene tra tion Numerical simulation

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Spin waves in the block checkerboard antiferromagnetic phase

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Chinese Physics B 2012年第2期21卷 509-520页

作者： lu Feng Dai xi Beijing National Laboratory for Condensed Matter Physics and Institute of PhysicsChinese Academy of SciencesBeijing 100190China

Motivated by the discovery of a new family of 122 iron-based superconductors, we present the theoretical results on the ground state phase diagram, spin wave, and dynamic structure factor obtained from the extended J1-J2 Heisenberg model. In the reasonable physical parameter region of K2Fe4Se5, we find that the block checkerboard antiferromagnetic order phase is stable. There are two acoustic spin wave branches and six optical spin wave branches in the block checker- board antiferromagnetic phase, which have analytic expressions at the high-symmetry points. To further compare the experimental data on neutron scattering, we investigate the saddlepoint structure of the magnetic excitation spectrum and the inelastic neutron scattering pattern based on linear spin wave theory.

关键词： spin wave phase diagram superconductivity

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Application of the cortical bone trajectory technique in posterior lumbar fixation

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World Journal of Clinical Cases 2023年第2期11卷 255-267页

作者： Shi-Bo Peng xi-Chuan Yuan Wei-zhong lu Ke-xiao Yu Department of Orthopedics Chongqing Nanchuan Hospital of Traditional Chinese MedicineChongqing 408400China Department of Orthopedics Chongqing Hospital of Traditional Chinese MedicineChongqing 400021China

The cortical bone trajectory(CBT) is a novel technique in lumbar fixation and *** unique caudocephalad and medial-lateral screw trajectories endow it with excellent screw purchase for vertebral fixation via a minimally invasive *** combined use of CBT screws with transforaminal or posterior lumbar interbody fusion can treat a variety of lumbar diseases,including spondylolisthesis or stenosis,and can also be used as a remedy for revision surgery when the pedicle screw *** has obvious advantages in terms of surgical trauma,postoperative recovery,prevention and treatment of adjacent vertebral disease,and the surgical treatment of obese and osteoporosis ***,the concept of CBT internal fixation technology appeared relatively recently;consequently,there are few relevant clinical studies,and the long-term clinical efficacy and related complications have not been ***,large sample and prospective studies are needed to further reveal the long-term complications and fusion *** a supplement to the traditional pedicle trajectory fixation technique,the CBT technique is a good choice for the treatment of lumbar diseases with accurate screw placement and strict indications and is thus deserving of clinical recommendation.

关键词： Cortical bone trajectory Management of midle line fusion lumbar interbody fusion lumbar surgery Review

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Mutual eclipses of J2 Europa by J1 Io observed at Yunnan Observatory in 2009

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Research in Astronomy and Astrophysics 2011年第10期11卷 1243-1248页

作者： xi-Liang Zhang zhong Liu National Astronomical Observatories/Yunnan Observatory Joint Laboratory for OpticalAstronomy Chinese Academy of Sciences Kunming 650011 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Mutual events between natural satellites include mutual occultation and mutual eclipse. Mutual eclipse is another kind of mutual occultation as viewed from the center of the Sun instead of the Earth. Two mutual eclipses of J2 Europa by J1 Io （2009 Aug. 28 and Sept. 12） were observed at Yunnan Observatory during the PHEMU09 international campaign. We will calculate the astrometric data of these Galilean satellites by analyzing and fitting the light curves we obtained. The limb-darkening was considered during modeling the light intensity of eclipsed satellites in the penumbra zone, by taking the Lommel-Seeliger scattering law into account. Several dynamical quantifies, such as the relative coordinates of the eclipsing satellite from the eclipsed one △α cos δ and △δ, impact parameter and mid-time corresponding to the impact parameter and the deviations O - C of observed △α cos d and △δ relative to ephemerides, were obtained for each event respectively.

关键词： eclipses -- kinematics and dynamics-methods -- planets and satellites individual: Galilean satellites

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China’s carbon neutrality:an extensive and profound systemic reform

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Frontiers of Environmental Science & Engineering 2023年第2期17卷 1-7页

作者： xi lu Dan Tong Kebin He State Key Joint Laboratory of Environment Simulation and Pollution Control and School of Environment Tsinghua UniversityBeijing 100084China Institute for Carbon Neutrality Tsinghua UniversityBeijing 100084China Beijing Laboratory of Environmental Frontier Technologies Tsinghua UniversityBeijing 100084China State Environmental Protection Key Laboratory of Sources and Control of Air Pollution Complex Beijing 100084China Department of Earth System Science Ministry of Education Key Laboratory for Earth System ModelingInstitute for Global Change StudiesTsinghua UniversityBeijing 100084China

China is the largest developing economy and carbon dioxide emitter in the world,the carbon neutrality goal of which will have a profound influence on the mitigation pathway of global climate *** transition towards a carbon-neutral society is integrated into the construction of ecological civilization in China,and brings profound implications for China’s socioeconomic ***,we not only summarize the major challenges in achieving carbon neutrality in China,but also identify the four potential new opportunities:namely,the acceleration of technology innovations,narrowing regional disparity by reshaping the value of resources,transforming the industrial structure,and co-benefits of pollution and carbon ***,we provide five policy suggestions and highlight the importance of balancing economic growth and carbon mitigation,and the joint efforts among the government,the enterprises,and the residents.

关键词： Carbon neutrality Energy structure Technology-dependent society Coordinated mitigation for air pollutants and CO_(2)

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LARGE EDDY SIMULATION OF FREE SURFACE TURBULENT CHANNEL FLOW WITH HEAT TRANSFER

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Journal of Hydrodynamics 2002年第1期14卷 16-22页

作者： zhong, Feng-Quan Liu, Nan-Sheng lu, xi-Yun Zhuang, Li-xian Dept. of Modern Mech. Univ. of Sci. and Technol. of China Hefei 230026 China

The Large Eddy Simulation (LES) was used to study the free-surface turbulent channel flow with passive heat transfer. The three-dimensional filtered incompressible Navier-Stokes equations and energy equation were numerically solved with dynamic Subgrid Scale (SGS) models for modeling turbulent stresses and heat flux. To compare the turbulent behavior of the free-surface and two-walled channel flows, the LES of two-walled turbulent channel flow was performed. The statistical quantities and flow structures of the free-surface turbulence with heat transfer in the vicinity of the free-surface were investigated. The results are also in good agreement with theoretical analysis and available results by Direct Numerical Simulation (DNS).

关键词： Computer simulation Heat transfer Mathematical models

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An experimental setup with controllable tuning parameters for studying the Kondo systems

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Science China(Physics,Mechanics & Astronomy) 2022年第4期65卷 121-122页

作者： zhong-Yi lu Department of Physics Renmin University of ChinaBeijing 100872China

The Kondo physics has been studied since the 1960 s in condensed matter physics[1,2],which is mainly determined by two competing factors namely the Kondo effect and the Ruderman-Kittel-Kasuya-Yosida(RKKY)interaction.

关键词： interaction Kondo condensed

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