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Journal of Integrative Agriculture 2014年第6期13卷 1268-1275页

作者： LIU Song-zhong ZHANG Qiang LIU Jun SUN Jian WEI Qin-ping Institute of Forestry & Pomology Beijing Academy of Agriculture & Forestry Sciences

Partial root-zone irrigation （PRI） has been proved to be an optimal water-saving irrigation technology, however, few studies were done on water transportation and distribution under PRI. The present study was performed to investigate the water transportation and distribution among the wet and dry root-zones and the shoot using deuterium water （D2O） in 1/4 root-zone PRI experiment. It also aimed to determine and analyze the D2O relative abundance within different types of roots and shoots. The results indicated that water could be transported from roots in wet root-zone to roots in dry root-zone and shoots within 2 h after irrigation. Water transportation in roots of wet-zone was carried out by absorbing root, 1-2 mm root, 2-5 mm root, and〉5 mm root progressively, while through a reverse process in three dry root-zones. In shoots, water was transported to trunk, central trunk, annual branches, shoot and leaf progressively. Thus in the young apple trees subjected to PRI, water was distributed ifrst in the roots, including the roots in the wet and dry root-zones, to satisfy the water need of roots itself, and then transported to the shoot within hours of irrigation.

关键词： apple D2O partial root-zone drying relative abundance transportation distribution

Effects of nano-sized Ag reinforcing particulates on the microstructure of Sn-0.7Cu solder joints

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International Journal of Minerals,Metallurgy and Materials 2009年第6期16卷 677-684页

作者： Feng Tai Fu Guo Zhi-dong Xia Yong-ping Lei Yao-wu Shi College of Materials science and Engineering Beijing University of Technology Beijing 100124 China

Composite solders were prepared by mechanically dispersing different volumes of nano-sized Ag particles into the Sn-0.7Cu eutectic solder. The effects of Ag particle addition on the microstructure of Sn-0.7Cu solder joints were investigated. Besides, the effects of isothermal aging on the microstructural evolution in the interfacial intermetallic compound （IMC） layer of the Sn-0.7Cu solder and the composite solder reinforced with 1vol% Ag particles were analyzed, respectively. Experimental results indicate that the growth rate of the interfacial IMC layer in the Ag particles reinforced composite solder joint is much lower than that in the Sn-0.7Cu solder joint during isothermal aging. The Ag particles reinforced composite solder joint exhibits much lower layer-growth coefficient for the growth of the IMC layer than the corresponding solder joint.

关键词： lead-free solder composite solder intermetallic compounds microstructure isothermal aging

Calculation of electron wave functions and refractive index of Ne

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science china(Physics,Mechanics & Astronomy) 2008年第10期51卷 1489-1495页

作者： ZHU Min LIU Wei ZHANG Tao Key Laboratory of Beam technology and Material Modification of Ministry of Education in beijing Normal University Institute of Low Energy Nuclear PhysicsBeijing Radiation CenterBeijing 100875China

The radial wave functions of inner electron shell and outer electron shell of a Ne atom were obtained by the approximate analytical method and tested by calculating the ground state energy of the Ne atom. The equivalent volume of electron cloud and the refractive index of Ne were calculated. The calculated refractive index agrees well with the experimental result. Relationship between the refractive index and the wave function of Ne was discovered.

关键词： electron cloud refractive index density function theory (DFT) Slater radial wave function (STO) variation calculus

Refraction of light in media

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science china(Physics,Mechanics & Astronomy) 2007年第5期50卷 591-600页

作者： ZHANG Tao Key Laboratory of Beam technology and Material Modification of Ministry of Education, Institute of Low Energy Nuclear Physics, beijing Normal University, beijing 100875, china beijing Radiation Center, beijing 100875, china Key Laboratory of Beam technology Material Modification of Ministry of Education Institute of Low Energy Nuclear Physics Beijing Normal University Beijing 100875 China beijing Radiation Center Beijing 100875 China

The roles of the magnetic field and electric field of the light are investigated when the light is refracted in the medium. The model of the electron cloud conductor is presented. Electron cloud in a molecule is treated as a conductor and the Faraday’s Law is applied to this conductor that is in the alternating magnetic field of the light. dBM/dt of the light gives rise to an alternating induced current on the electron cloud conductor, and the light exchanges energy, i.e. the refractive energy, with the elec- tron cloud conductor. Formulas of refractive index, which is the ratio of light speed in vacuum to that in the medium, are derived with this model. These formulas are tested with several mediums and Langevin’s diamagnetic susceptibility of helium gas, and the results are in good agreement with the measured data. The anisotropy and the nonlinearity of the refractive index are explained with the theory described in this work.

关键词： refractive index, light, speed, medium, propagation

Impurity-Free Vacancy Diffusion Technique for InGaAsP/InP Multiple Quantum Well Laser Structure

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Chinese Physics Letters 2001年第1期18卷 100-102页

作者： HAN De-Jun NIU Jia-Sheng ZHU Hong-Liang ZHU Hong-Qing ZHUANG Wan-Ru Key Laboratory in University for Radiation Beam technology and Materials Modification Institute of Low Energy Nuclear PhysicsBeijing Normal UniversityBeijing 100875 and Beijing Radiation CenterBeijing 100875 Institute of Semiconductors Chinese Academy of SciencesBeijing 100083

Bandgap tuning of the InGaAsP/InP multiple quantum well(MQW)laser structure by the impurity-free vacancy diffusion(IFVD)is investigated using *** has been demonstrated that the effects of the plasma bombardment to the sample surface involved in the IFVD technique can enhance the intermixing of the InGaAsP/InP MQW laser *** reliability of the IFVD technique,particularly the effects of the surface decomposition and the intrinsic defects formed in the growth or preparation of the wafer,has been discussed.

关键词： InGaAsP/InP tuning Quantum

STUDY ON DYNAMIC J-INTEGRAL OF MECHANICAL HETEROGENEOUS WELDED JOINT

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Acta Metallurgica Sinica(English Letters) 2004年第6期17卷 934-939页

作者： F.Q.Tian D.Y.He X.Y.Li Y.W.Shi D.Zhang InstituteofCompositeMaterials ShanghaiJiaotongUniversityShanghai200030China SchoolofMaterialsscienceandEngineering BeijingPolytechnicUniversityBeijing100022China

Welded joint is a mechanical heterogeneous body, and mechanical heterogeneity has great effect on dynamic fracture behaviour of welded joints. In the present investigation, dynamic response curve and dynamic J-integral of practical undermatched welded joint and whole base and whole weld three-point-bend (TPB) models containing longitudinal crack are com- puted. Dynamic J-integral is evaluated using virtual crack extension (VCE) method and the computation is performed using MARC finite element code. Because of the effect of inertia, dynamic load response curve of computed model waves periodically. Dynamic J-integral evaluated by VCE method is path independent. The effect of inertia has little influence on dynamic J-integral curve. The value of dynamic J-integral of undermatched welded joint is lower than that of whole base metal and higher than that of whole weld metal. The results establish the foundation of safety evaluation for dynamic loaded welded structures.

关键词： virtual crack extension welded joint dynamic response curve dynamic J-integral

Effects of particle size on the mechanical properties of particle-reinforced Sn-Ag composite solder joint

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science china(Technological sciences) 2009年第1期52卷 243-251页

作者： TAI Feng GUO Fu College of Materials science and Engineering Beijing University of TechnologyBeijing 100124China

Particulate size has significant influenced on the mechanical properties of particle-reinforced composite solder joints. In this current research, Cu or Ni reinforcement particles were mechanically added to the Sn-3.5Ag eutectic solder, and the effects of the particle size on the mechanical properties of particle-reinforced composite solder joint were systematically studied. This investigation touched on how mechanical properties of the solder joints are affected by particles size. A quantitative formula was set up to correlate the mechanical property of the solder joint with particle size in different processing conditions. Besides, the fracture mechanism of the composite solder joint was analyzed.

关键词： composite solder size effect mechanical property fracture mechanism

Hydrodynamic behavior of an internally circulating fluidized bed with tubular gas distributors

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Particuology 2013年第6期11卷 664-672页

作者： Wenli Zhao Tiefeng Wang Chenjing Wang Zuoliang Sha beijing Key Laboratory of Green Reaction Engineering and technology Department of Chemical EngineeringTsinghua University Tianjin Key Laboratory of Marine Resources and Chemistry Tianjin University of Science and Technology

To better understand the hydrodynamic behavior of an internally circulating fluidized bed, solids holdup in the down-comer （Eso）, solids circulation rate （Gs） and gas bypassing fraction （from down-comer to riser y^R, and from riser to down-comer yRD） were experimentally studied. The effects of gas velocities in the riser and in the down-comer （UR and UD）, orifice diameter in the draft tube （dor）, and draft tube height （HR） were investigated. Experimental results showed that increase of gas velocities led to increase in Gs and yDR, and slight decrease in yeD. Larger orifice diameter on the draft tube led to higher 8sD, Gs and yDR, but had insignificant influence on YRD. with increasing draft tube height, both Gs and YDR first increased and then decreased, while yRD first decreased and then increased. Proposed correlations for predicting the hydrodynamic parameters agreed reasonably well with experimental values.

关键词： Internally circulating fluidized bed Solids holdup Solids circulation rate Gas bypassing fraction

Research on the navigation method of large-scale differential tail-control improvised guided munitions based on rotational speed constraints

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Defence technology（防务技术） 2024年第8期38卷 155-170页

作者： Ning Liu Wenjiang Zhao Yao Wang Kai Shen Zhong Su Wenhao Qi Yuedong Xie beijing Key Laboratory of High Dynamic Navigation technology Beijing Information Science and Technology UniversityBeijing100192China Hua an Industry Group Co. Ltd.Qiqihar161006China Integrated Navigation and Intelligent Navigation Laboratory Beijing Institute of TechnologyBeijing100081China beijing Institute of technology Beijing100081China

In the process of launching guided projectile under the conventional system, it is difficult to effectively obtain the precise navigation parameters of the projectile in the high dynamic environment. Aiming at this problem, this paper describes a new system of guided ammunition based on tail spin reduction. After analyzing the mechanism of the ammunition's tail spin reduction, a navigation method of large scale difference tail control simple guided ammunition based on speed constraint is proposed. In this method,the corresponding navigation constraints can be carried out by combining the rotation speed state of the ammunition itself, and the optimal solution of navigation parameters during the flight of the missile can be obtained by Extended Kalman Filter(EKF). Finally, the performance of the proposed method was verified by the simulation environment, and the hardware-in-the-loop simulation test and flight test were carried out to verify the performance of the method in the real environment. The experimental results show that the proposed method can achieve the optimal estimation of navigation parameters for simple guided ammunition with large-scale difference tail control. Under the conditions of simulation test and hardware-in-loop simulation test, the position and velocity errors calculated by the method in this paper converged. Under the condition of flight test, the spatial average error calculated by the method described in this paper is 6.17 m, and the spatial error of the final landing point is 3.50 *** this method, the accurate acquisition of navigation parameters in the process of projectile launching is effectively realized.

关键词： Guided projectiles Tail spin reduction RPM constraints Combined navigation Extended Kalman filter(EKF)

An off-and-towards-equilibrium strategy for vibrational control of structures

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Earthquake Engineering and Engineering Vibration 2006年第2期5卷 195-203页

作者：杨润林童迈周锡元闫维明刘锡荟 Department of Civil Engineering Civil & Environment Engineering School University of Science and Technology Beijing National Center for Earthquake Engineering Research SUNY at Buffalo 109 Red Jacket Quad. Buffalo NY 14261 USA Professor School of Architecture and Civil Engineering Beijing University of Technology Electronic Information Center Ministry of Information Industry

Traditional control strategies have difficulty handling nonlinear behavior of structures, time variable features and parameter uncertainties of structural control systems under seismic excitation. An off-and-towardsequilibrium （OTE） strategy combined with fuzzy control is presented in this paper to overcome these difficulties. According to the OTE strategy, the control force is designed from the viewpoint of a mechanical relationship between the motions of the structure, the exciting force and the control force. The advantage of the OTE strategy is that it can be used for a variety of control systems. In order to evaluate the performance of the proposed strategy, the seismic performance of a three-story shear building with an Active Tendon System （ATS） using a Fuzzy Logic Controller （FLC） is studied. The main advantage of the fuzzy controller is its inherent robustness and ability to handle any nonlinear behavior of structures. However, there are no design guidelines to set up the corresponding control rule table for a FLC. Based on the proposed strategy for the FLC, a control rule table associated with the building under study is developed, which then allows formation of a detailed algorithm. The results obtained in this study show that the proposed strategy performs slightly better than the linear quadratic regulator （LQR） strategy, while possessing several advantages over the LQR controller. Consequently, the feasibility and validity of the proposed strategy are verified.

关键词： structural vibration control control strategy off-and-towards-equilibrium control fuzzy control seismicexcitation active tendon system