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Search Results: 1 - 10 of 237935 matches for " L Peng-mei "
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Synthesis of biodiesel by transition metal doped Fe/Zn double metal cyanide complex catalysts
过渡金属掺杂亚铁锌双金属氰化物催化合成生物柴油的研究
YANG Ling-mei,LPeng-mei,LUO Wen,LI Hui-wen,WANG Zhong-ming,YUAN Zhen-hong,
杨玲梅,吕鹏梅,罗文,李惠文,王忠铭,袁振宏
燃料化学学报 , 2012,
Abstract: Effects of transition metals(La,Ce,Zr,Mn) on catalytic performance of double metal cyanide(DMC) catalysts for biodiesel synthesis were studied.The structure and performance of the catalysts were studied using XRD,FT-IR,ICP,BET et al.The experimental results showed that the DMC catalyst prepared by adding 1% of transition metal salts had higher activity.The catalyst with highest catalytic activity was prepared by adding 1% of La(NO3)3·nH2O.Under the conditions of methanol/oil mol ratio of 16∶1,catalyst amount of 2% and temperature of 160 ℃,a high yield(99.3%) of fatty acid methyl esters(FAME) was obtained within 7 h.The analytical results showed that adding 1% of transition metals did not change the molecular formula of Fe(II)-Zn double metal cyanide complex catalysts,while it improved particle dispersion,decreased particle size and increased surface area.This was the reason that transition metals promoted catalysts had higher activity.
An Experimental Investigation of Hydrogen Production from Biomass
LU Peng-mei,
吕鹏梅,常杰,付严,王铁军,陈勇,祝京旭
过程工程学报 , 2003,
Abstract: In gaseous products of biomass steam gasification, there exist a lot of CO, CH4 and other hydrocarbons that can be converted to hydrogen through steam reforming reactions. There exists potential hydrogen production from the raw gas of biomass steam gasification. In the present work, the characteristics of hydrogen production from biomass steam gasification were investigated in a small-scale fluidized bed. In these experiments, the gasifying agent (air) was supplied into the reactor from the bottom of the reactor and the steam was added into the reactor above biomass feeding location. The effects of reaction temperature, steam to biomass ratio, equivalence ratio (ER) and biomass particle size on hydrogen yield and hydrogen yield potential were investigated. The experimental results showed that higher reactor temperature, proper ER, proper steam to biomass ratio and smaller biomass particle size will contribute to more hydrojzen and potential hydrogen yield.
Dimethyl Ether Synthesis from Biomass by Thermochemical Method
生物质热化学转化合成二甲醚
WANG Tie-jun,CHANG Jie,LU Peng-mei,FU Yan,LU Hao,
王铁军,常杰,吕鹏梅,付严,鲁皓
过程工程学报 , 2005,
Abstract: 在鼓泡流化床反应器内,采用空气?水蒸汽气化松木粉制备了富氢燃气,在下游的固定床重整反应器内,通过添加沼气重整富氢燃气,调变化学当量比,制备了含氮的生物质合成气.在Cu?Zn?Al/HZSM?5催化剂上,对生物质合成气一步法合成二甲醚进行了实验研究.在280℃,4MPa,1000~4000h?1的条件下,CO的单程转化率达到67%,单位质量催化剂的最大二甲醚时空收率0.358g/(g?h)DME/(催化剂?h)];通过添加沼气重整,90%以上的生物质碳转化为合成气,二甲醚的最大产量为0.244kg/kg(DME/生物质).
Reforming of raw biomass fuel gas over monolithic catalyst
整体式催化剂催化重整净化生物质粗燃气性能研究
WANG Chen-guang,WANG Tie-jun,LU Peng-mei,CHANG Jie,XU Ying,
王晨光,王铁军,吕鹏梅,常 杰,徐 莹
燃料化学学报 , 2007,
Abstract: 采用分步浸渍法制备了以Ni为活性组分的整体式催化剂,以萘为生物质焦油的模型化合物,考察了整体式催化剂催化重整生物质粗燃气的性能,通过元素分析、热重分析等方法对催化剂的表面积炭进行了研究。结果表明,在整体式催化剂作用下,108 h的连续反应中,CH4的平均转化率达到92%,最高达到93.8%。合成气H2/CO的摩尔比保持0.95左右,最高达到1.15,适合液体燃料合成。CO2的平均转化率为80%,最高达到88%。实验中添加萘模拟生物质焦油的成分,经检测焦油全部转化为H2、CO及微量轻质组分。反应连续进行108 h,未发现反应器压降变化和CH4与焦油转化率的下降,表明整体式催化剂具有较好的活性和抗积炭性能。
Derivation of a Matrix-valued Boltzmann Equation for the Hubbard Model
Martin L. R. Fürst,Jani Lukkarinen,Peng Mei,Herbert Spohn
Physics , 2013, DOI: 10.1088/1751-8113/46/48/485002
Abstract: For the spin-$\{1}{2}$ Fermi-Hubbard model we derive the kinetic equation valid for weak interactions by using time-dependent perturbation expansion up to second order. In recent theoretical and numerical studies the kinetic equation has been merely stated without further details. In this contribution we provide the required background material.
The Interdecadal Variation of Precipitation Pattern over China during Summer and Its Relationship with the Atmospheric Internal Dynamic Processes and Extra-Forcing Factors
夏季中国降水型的年代际变化与大气内部动力过程及外强迫因子关系
ZHANG Qing-Yun,L Jun-Mei,YANG Lian-Mei,WEI Jie,PENG Jing-Bei,
张庆云,吕俊梅,杨莲梅,等
大气科学 , 2007,
Abstract: 根据中国160站月平均降水、NCEP/NCAR的再分析资料以及英国气象局哈德莱中心1900~1999年全球1°×1°格点月平均海表温度距平资料,利用物理量诊断、EOF分析等方法,探讨东亚季风区大气环流内部动力过程与大气外强迫因子(海温)年代际变化及对中国夏季降水型的影响。分析发现,中国东部地区、西北地区夏季降水型有各自不同的年代际变化趋势;中国东部夏季降水型及东亚夏季风环流年代际变化趋势与大气外强迫因子北太平洋中纬度海温年代际变化(PDO)关系密切;中国西北地区夏季降水年代际变化与大气内部动力过程中纬度西风带扰动动能年代际减弱有关。
The ACS Fornax Cluster Survey. VI. The Nuclei of Early-Type Galaxies in the Fornax Cluster
Monica L. Turner,Patrick Cote,Laura Ferrarese,Andres Jordan,John P. Blakeslee,Simona Mei,Eric W. Peng,Michael J. West
Physics , 2012, DOI: 10.1088/0067-0049/203/1/5
Abstract: The Advanced Camera for Surveys (ACS) Fornax Cluster Survey is a Hubble Space Telescope program to image 43 early-type galaxies in the Fornax cluster, using the F475W and F850LP bandpasses of the ACS. We employ both 1D and 2D techniques to characterize the properties of the stellar nuclei in these galaxies, defined as the central "luminosity excesses" relative to a Sersic model fitted to the underlying host. We find 72+/-13% of our sample (31 galaxies) to be nucleated, with only three of the nuclei offset by more than 0.5" from their galaxy photocenter, and with the majority of nuclei having colors bluer than their hosts. The nuclei are observed to be larger, and brighter, than typical Fornax globular clusters, and to follow different structural scaling relations. A comparison of our results to those from the ACS Virgo Cluster Survey reveals striking similarities in the properties of the nuclei belonging to these different environments. We briefly review a variety of proposed formation models and conclude that, for the low-mass galaxies in our sample, the most important mechanism for nucleus growth is probably infall of star clusters through dynamical friction, while for higher mass galaxies, gas accretion triggered by mergers, accretions and tidal torques is likely to dominate, with the relative importance of these two processes varying smoothly as a function of galaxy mass. Some intermediate-mass galaxies in our sample show a complexity in their inner structure that may be the signature of "hybrid nuclei" that arose through parallel formation channels.
Level spacing distribution of a Lorentzian matrix at the spectrum edge
Adel Abbout,Peng Mei
Physics , 2012,
Abstract: Effective Hamiltonians can explain in a much simpler way the physics behind a scattering process. Chaotic scattering is directly related to Lorentzian Hamiltonians which, because of their properties, can be reduced to a $2\times 2$ matrix problem in the case of two modes scattering. In this framework, we provide the distribution of level spacing of its eigenvalues and show that this special kind of distribution has no mean level spacing (divergent) and is characterized by a geometrical decay law. We discuss the relation of this distribution to the averaged level spacing at the edge of the spectrum of $N \times N$ Lorentzian matrices.
The ACS Fornax Cluster Survey. IX. The Color-Magnitude Relation of Globular Cluster Systems
S. Mieske,A. Jordan,P. Cote,E. Peng,L. Ferrarese,J. Blakeslee,S. Mei,H. Baumgardt,J. Tonry,L. Infante,M. West
Physics , 2010, DOI: 10.1088/0004-637X/710/2/1672
Abstract: We investigate the color-magnitude relation for globular clusters (GCs) -- the so-called "blue tilt" -- detected in the ACS Fornax Cluster Survey and using the combined sample of GCs from the ACS Fornax and Virgo Cluster Surveys. We find a tilt of gamma_z=d(g-z)/dz=-0.0257 +- 0.0050 for the full GC sample of the Fornax Cluster Survey (~5800 GCs). This is slightly shallower than the value gamma_z=-0.0459 +- 0.0048 found for the Virgo Cluster Survey GC sample (~11100 GCs). The slope for the merged Fornax and Virgo datasets (~16900 GCs) is gamma_z=-0.0293 +- 0.0085, corresponding to a mass-metallicity relation of Z ~ M^0.43. We find that the blue tilt sets in at GC masses in excess of M ~ 2*10^5 M_sun. The tilt is stronger for GCs belonging to high-mass galaxies (M_* > 5 * 10^10 M_sun) than for those in low-mass galaxies (M_* < 5 * 10^10 M_sun). It is also more pronounced for GCs with smaller galactocentric distances. Our findings suggest a range of mass-metallicity relations Z_GC ~ M_GC^(0.3-0.7) which vary as a function of host galaxy mass/luminosity. We compare our observations to a recent model of star cluster self-enrichment with generally favorable results. We suggest that, within the context of this model, the proto-cluster clouds out of which the GCs formed may have had density profiles slightly steeper than isothermal and/or star formation efficiencies somewhat below 0.3. We caution, however, that the significantly different appearance of the CMDs defined by the GC systems associated with galaxies of similar mass and morphological type pose a challenge to any single mechanism that seeks to explain the blue tilt. We therefore suggest that the merger/accretion histories of individual galaxies have played a non-negligible role determining the distribution of GCs in the CMDs of individual GC systems.
Simulation Study of Three Types of Distributed Power Based on EMTDC  [PDF]
Peng-tao Mu, Dong-mei Zhao
Energy and Power Engineering (EPE) , 2013, DOI: 10.4236/epe.2013.54B008
Abstract: In order to analyze the performances of directly-driven permanent magnet synchronous generator wind turbine (PMSG) connecting to the grid, photovoltaic array and microtubine, dynamic models of them are established. The validity of the established models and proposed control strategies are demonstrated by simulation system under the software package PSCAD/EMTDC.
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