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Root Growth Potential and energy Sources for New Root Growth of Three Conifer Species in Northern China

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北京林业大学学报 1993年第S3期 10-22页

作者： Liu Yong Forest resources college,Beijing Forestry University

Seedlings of Pinus sylvestris var. mongolica, Larix principis—rupprechtii and Platycladus orientaliswere lifted from the nursery in March and transplanted to favorable growing conditions in a controlledenvironment chamber. The test of RGP showed that Platycladus orientalis seedlings had the greatest RGP amongthe three species, any one of the four parameters as TNR, TNR>1, TLR>1 and SAI could representthe RGP of Platycladus orientalis. However, at least two parameters (TNR and any one of TNR>1,TLR>1, SAI)must be used to represent the RGP of Larix principis—rupprechtii and Pinus sylvestris *** seedlings due to the weak correlation between root initiation and root elongation for the twospecies. The results of the RGP test and carbohydrate analysis for different treatments demonstrated thatcurrent photosynthate is needed for new root growth in Pinus sylvestris var. mongolica seedlings, whereasstored-carbohydrates provided the energy source for new root initiation. Current photosynthate is also neededfor root elongation in Larix principis — rupprechtii seedlings; New root growth of Platycladus orientalisseedlings is primarily caused by current photosynthate, but some reserve materials may be utilized at thesame time if photosynthesis is inadequate to meet growth demands.

关键词： root growth potential(RGP) current photosynthate stored carbohydrates

Identification of secondary organic aerosols based on aerosol mass spectrometry

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中国科学：化学英文版 2010年第12期53卷 2593-2599页

作者： HUANG XiaoFeng 1,ZHAO QianBiao 1,2.HE LingYan 1,HU Min 2.BIAN QiJing 3.XUE Lian 1 & ZHANG YuanHang 2.1 Key Laboratory for Urban Habitat Environmental Science and Technology School of Environment and {3.,Peking University Shenzhen Graduate School,Shenzhen 518055,China 2.State Key Joint Laboratory of Environmental Simulation and Pollution Control college of Environmental Sciences and Engineering,Peking University,Beijing 100871,China 3.Division of Environment,Hong Kong University of Science & Technology,Hong Kong,China 1. Key Laboratory for Urban Habitat Environmental Science and Technology School of Environment and energy Peking University Shenzhen Graduate School Shenzhen 518055 China2. State Key Joint Laboratory of Environmental Simulation and Pollution Control college of Environmental Sciences and Engineering Peking University Beijing 100871 China3. Division of Environment Hong Kong University of Science & Technology Hong Kong China

Secondary organic aerosol (SOA) is one of the major components of aerosols in the atmosphere and has not been well understood so *** to the complex chemical composition of organic aerosols,the identification of SOA has been a hotspot and difficult issue in the field of aerosol *** study attempts to quantitatively identify SOA in winter of Shenzhen based on positive matrix factorization (PMF) *** sources were resolved and SOA was identified subsequently according to the characteristic ion fragments measured by highly time-resolved aerosol mass spectrometer *** showed that in the winter of Shenzhen the average SOA concentration was 9.41±6.3. g/m 3.accounting for 3..9±2..8% of the total organic *** with primary organic aerosol (POA),the SOA concentrations had no large variation,suggestive of characteristics of regional secondary *** ratio of SOA/BC had pronounced diurnal variation,similar to that of O x (O3.NO2.,indicating SOA formation was significantly controlled by activity of photochemistry in the *** most effective period for SOA formation was from 9 am～3.pm since the SOA/BC ratio increased by 12.% during this *** study provides a new technical method and a new idea for SOA investigation.

关键词： secondary organic aerosol aerosol mass spectrometry positive matrix factorization (PMF)

Molecular dynamics simulation of thermal stability of nanocrystalline vanadium

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Science China(Technological Sciences) 2006年第4期49卷 400-407页

作者： WEI Mingzhi1, XIAO Shifang1, YUAN Xiaojian2.& HU Wangyu1,2.1. Material Science and Engineering college, Hunan University, Changsha 410082. China 2. Department of Applied Physics, Hunan University, Changsha 410082. China Material Science Engineering college Hunan University Changsha 410082 China Department of Applied Physics Hunan University Changsha 410082 China

The microstructure and thermal stability of nanocrystalline vanadium with an average grain size ranging from 2.86 to 7.50 nm are calculated by means of the analytic embedded-atom method and molecular dynamics. The grain boundary and nanocrystal- line grain atoms are differentiated by the common neighbor analysis method. The results indicate that the fraction of grain boundary increases with the grain size decreasing, and the mean energy of atoms is higher than that of coarse crystals. The thermal-stable tem- peratures of nanocrystalline vanadium are determined from the evolution of atomic energy, fraction of grain boundary and radial distribution function. It is shown that the stable tem- perature decreases obviously with the grain size decreasing. In addition the reasons which cause the grain growth of nanocrystalline vanadium are discussed.

关键词： nanocrystalline, embedded-atom method, molecular dynamics, thermal stability.

The forbidden transitions for magnesium isoelectronic sequences

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原子与分子物理学报 2001年第3期18卷 317-324页

作者： YI You-gen 1,2.3., ZHU Zheng-he 2.TANG Yong-jian 3.ZHENG Zhi-jian 3.(1.Department of Physics, Xiangtan Normal college,Xiangtan 4112.1 2.Institute of Atomic and Molecular Physics, Sichuan University, Chengdu 610065 3.Southwestern Institu 湘潭师范学院湖南湘潭 411201 四川大学四川成都 610065 中国工程物理研究院西南核物理与化学所四川成都 610003

Using the full relativistic quantum mechanics (GRASP2., we have calculated systematically the 3. 2. 3. 1 and 3. 1- 3. 0 magnetic dipole M1 energy level separations, transition probabilities and oscillator strengths in the 3.3. configuration of the magnesium sequences. The two configurations 3.3. and 3.3. are used. Breit and QED effects are treated as high-order perturbations. Excellent comparison is obtained throughout the range of atomic number Z, and the inclusion of the 3.3. configuration gives results which are in good agreements with recent experimental and reference data.

关键词：镁原子禁戒跃迁等电子数序

An adaptive scaled boundary finite element method by subdividing subdomains for elastodynamic problems

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Science China(Technological Sciences) 2011年第S1期54卷 101-110页

作者： ZHANG ZiHua 1,2.YANG ZhenJun 2.LIU GuoHua 1 & HU YunJin 1 1 college of Civil Engineering and Architecture,Zhejiang University,Hangzhou 3.0058,China 2.School of Engineering,University of Liverpool,L69 3.Q,UK 1. college of Civil Engineering and Architecture Zhejiang University Hangzhou 310058 China 2. School of Engineering University of Liverpool Liverpool L69 3GQ UK

The scaled boundary finite element method(SBFEM) is a semi-analytical numerical method,which models an analysis domain by a small number of large-sized subdomains and discretises subdomain boundaries *** a subdomain,all fields of state variables including displacement,stress,velocity and acceleration are semi-analytical,and the kinetic energy,strain energy and energy error are all integrated *** advantages are taken in this study to develop a posteriori h-hierarchical adaptive SBFEM for transient elastodynamic problems using a mesh refinement procedure which subdivides *** only a small number of subdomains are subdivided,mesh refinement is very simple and efficient,and mesh mapping to transfer state variables from an old mesh to a new one is also very simple but *** {3. examples with stress wave propagation were *** results show that the developed method is capable of capturing propagation of steep stress regions and calculating accurate dynamic responses,using only a fraction of degrees of freedom required by adaptive finite element method.

关键词： scaled boundary finite element method subdivision of subdomains h-hierarchical adaptivity mesh mapping transient elastodynamics

Improving Film Cooling Performance by Using One-Inlet and Double-Outlet Hole

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Journal of Thermal Science 2010年第5期19卷 430-437页

作者： Guang-chao Li and Wei Zhang Aeroengine and energy Engineering college,Shenyang Areospace University Shenyang China 11013. Aeroengine and energy Engineering college Shenyang Areospace University Shenyang China

The film cooling performance of a trunk-branch hole is investigated by numerical simulation in this paper. The geometry of the hole is a novel cooling concept, which controls the vortices-pair existing at the mink hole outlet using the injection of the branch hole. The trunk-branch holes require easily machinable round hole as compared to the shaped holes. The flow cases were considered at the blowing ratios of 0.5, 0.75, 1.0, 1.5 and 2.0. At the low blowing ratio of 0.5, the vortices-pair at the outlet of the trunk hole is reduced and the laterally coverage of the film is improved. At the high blowing ratio of 2.0, the vortices-pair is killed by the vortex which is produced by the injection of the branch hole. The flow rate of the two outlets becomes more significantly different when the blowing ratio increases from 0.75 to 2.0. The discharge coefficients increase 0.15 and the laterally averaged film effectiveness improve 0.2.as compared to the cylindrical holes. The optimal blowing ratios occur at M=1.0 or M= 1.5 according to the various locations downstream of the holes.

关键词： aerospace propulsion system gas turbine film cooling heat transfer

X-ray spectra induced by slow highly charged Ar^(q+) ions in collision with Nb surface

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Science China(Physics,Mechanics & Astronomy) 2008年第10期51卷 1463-1469页

作者： YANG ZhiHu1, CUI Ying2. CHEN XiMeng2. SONG ZhangYong1, SHAO JianXiong2. RUAN FangFang1, ZHANG HongQiang2. DU Juan2. LIU YuWen2. GAO ZhiMing2. ZHANG XiaoAn3. ZHU KeXin1, YU DeYang1 & CAI XiaoHong1 1 Institute of Modern Physics, Chinese Academy of Sciences, Lanzhou 73.000, China 2.Department of Modern Physics, Lanzhou University, Lanzhou 73.000, China 3.Department of Physics, Xianyang Normal college, Xianyang 712.00, China 1. Institute of Modern Physics Chinese Academy of Sciences Lanzhou 730000 China 2. Department of Modern Physics Lanzhou University Lanzhou 730000 China 3. Department of Physics Xianyang Normal College Xianyang 712000 China

The X-ray spectra of Nb surface induced by Arq+ (q =16,17) ions with the energy range from 10 to 2. keV/q were studied by the optical spectrum technology. The experimental results indicate that the multi-electron excitation occurred as a highly charged Ar16+ ion was neutralized below the metal surface. The K shell electron of Ar16+ was excited and then de-excited cascadly to emit K X-ray. The intensity of the X-ray emitted from K shell of the hollow Ar atom decreased with the increase of projectile kinetic energy. The intensity of the X-ray emitted from L shell of the target atom Nb increased with the increase of projectile kinetic energy. The X-ray yield of Ar17+ is three magnitude orders larger than that of Ar16+.

关键词： highly charged ion hollow atom multi-electron X-ray

Microstructural Evolution of Surface Layer of TWIP Steel Deformed by Mechanical Attrition Treatment

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Journal of Iron and Steel Research International 2012年第3期19卷 38-46页

作者： LI Da-zhao1,2. WEI Ying-hui1, HOU Li-feng1, LIN Wan-ming1 (1. college of Materials and Engineering, Taiyuan University of Technology, Taiyuan 03.02., Shanxi, China 2. college of Materials and Engineering, North University of China, Taiyuan 03.051, Shanxi, China) [a] college of Materials and Engineering Taiyuan University of Technology Taiyuan 030024 Shanxi China [b] college of Materials and Engineering North University of China Taiyuan 030051 Shanxi China

A nanocrystalline layer was synthesized on the surface of TWIP steel samples by surface mechanical attri- tion treatment （SMAT） under varying durations. Microhardness variation was examined along the depth of the de- formation layer. Microstructural characteristics of the surface at the TWIP steel SMATed for 90 min were observed and analyzed by optical microscope, x-ray diffraction, transmission and high-resolution electron microscope. The re- sults show that the orientation of austenite grains weakens, and a-martensite transformation occurs during SMAT. During the process of SMAT, the deformation twins generate and divide the austenite grains firstly~ then a-martens- ite transformation occurs beside and between the twin bundles~ after that the martensite and austenite grains rotate to accommodate deformation, and the orientations of martensite and between martensite and residual austenite increase; lastly the randomly oriented and uniform-sized nanocrystallir^e layers are formed under continuous deformation.

关键词： SMAT technology twinning stacking fault energy deformation twin

Adsorption Breakthrough of Benzene in the Fixed Bed of Modified Activated Carbon under Different Humidity Conditions

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Journal of Wuhan University of Technology(Materials Science) 2010年第3期25卷 499-503页

作者：李晶 college of Chemistry and Chemical Engineering Zhongkai University of Agriculture and Engineering

The breakthrough curves of benzene and water on modified activated carbons（ACs） were ***-programmed desorption（TPD） experiments were conducted to measure the TPD curves of benzene and water on modified and unmodified ACs and to estimate the activation energy for the desorption of benzene on the modified *** with unmodified ACs,two modified ACs were prepared by using two different types of silane,designated by KH560 and *** results showed that the activation energy for the desorption of benzene on KH560/AC and 1706/AC was higher than that on unmodified *** addition,the activation energy for the desorption of water on KH560/AC and 1706/AC was lower than that on unmodified *** breakthrough curves of benzene obtained from the experimental observations under different humidity conditions were compared with the results of the TPD *** results show that the modified ACs are less affected by water,whereas the unmodified ACs are more affected by water,indicating that surface modification by organosilane compounds can improve the adsorption of benzene on the activated carbo,which weakens the adsorption of water.

关键词： activated carbon benzene water TPD activation energy of desorption breakthrough curves