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Search Results: 1 - 10 of 80836 matches for " Junmin Liu "
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Evaluating Reference Crop Evapotranspiration (ETo) in the Centre of Guanzhong Basin—Case of Xingping & Wugong, Shaanxi, China  [PDF]
Hussein I. Ahmed, Junmin Liu
Engineering (ENG) , 2013, DOI: 10.4236/eng.2013.55055
Abstract: In this paper, the Penman-Monteith method was applied to evaluate the reference crop evapotranspiration. A reliable estimation of the reference evapotranspiration (ETo) is of critical importance and required accurate estimates to close the water balance. The aim of this paper is estimating the reference evapotranspiration (ETo) as preliminary to use for groundwater modeling in the area. Based on FAO-Penman-Monteith method, ETo calculator software was applied. Meteorological data within this study were obtained from two gauges stations (Xing ping and Wu gong) and available literatures. The results indicated that the values of ETo for a period (1981-2009)29 yearsin two stations approximately the same. Specifically, is ranged between 0.4 - 6.9 mm /day, 0.4 - 6.7 mm/day and the average value is 2.6 mm/ day, 2.6 mm/day in Xing ping and Wu gong respectively. In addition, the maximum values were occurred in summer season (May, June and July). The result also found that the correlation coefficient ≈ 1. Moreover, “ETo” was increasing by recent years. The reference crop evapotranspiration for some crops were calculated.
MNi4.8Sn0.2(M=La, Nd)-supported multi-walled carbon nanotube composites as hydrogen storage materials
JianWei Ren,ShiJun Liao,JunMin Liu
Chinese Science Bulletin , 2007, DOI: 10.1007/s11434-007-0242-9
Abstract: Two composites LaNi4.8Sn0.2/CNTs and NdNi4.8Sn0.2/CNTs were prepared by an impregnation-reduction method. Their hydrogen storage capacity could reach up to 2.96 wt% and 2.88 wt% respectively at room temperature and 1.0 MPa pressure. These values, which might result from the synergetic effect between the alloy nanoparticles and the pretreated CNTs, were three times higher than those of the unsupported MNi4.8Sn0.2 (M=La, Nd) alloys under the same conditions. XRD and TEM revealed that the alloy particles were uniformly dispersed on the CNTs and the average particle size was ca. 30 nm. The composites also showed good stability and the hydrogen storage capacity decreased by less than 6% after 100 adsorption-desorption cycles. Moreover, no noticeable change in crystalline structure was observed for the composites.
Hydrogen storage of multiwalled carbon nanotubes coated with Pd-Ni nanoparticles under moderate conditions
Jianwei Ren,Shijun Liao,Junmin Liu
Chinese Science Bulletin , 2006, DOI: 10.1007/s11434-006-2216-8
Abstract: A type of novel material with a high hydrogen storage capacity was prepared by supporting PdNi18 alloy nanoparticles, which were synthesized by using a new colloid method, on the surface of pretreated multiwalled carbon nanotubes (MWCNTs). The average PdNi18 alloy particle sizes calculated from XRD patterns were ca. 3 nm, and the high dispersion of these particles on MWCNTs was confirmed by TEM image. Hydrogen storage performance of the composite was investigated under moderate pressure (0.1–1.5 MPa) at room temperature, and a maximum storage capacity of ca. 2.3 wt% was achieved under 1.5 MPa at room temperature, which was much higher than that reported previously under the same conditions.
MNi4.8Sn0.2(M=La, Nd)-supported multi-walled carbon nanotube composites as hydrogen storage materials
MNi4.8Sn0.2(M=La, Nd)-supported multi-walled carbon nanotube composites as hydrogen storage materials

REN JianWei,LIAO ShiJun,LIU JunMin,
REN
,JianWei,LIAO,ShiJun,LIU,JunMin

科学通报(英文版) , 2007,
Abstract: Two composites LaNi4.8Sn0.2/CNTs and NdNi4.8Sn0.2/CNTs were prepared by an impregnation-reduction method. Their hydrogen storage capacity could reach up to 2.96 wt% and 2.88 wt% respectively at room temperature and 1.0 MPa pressure. These values, which might result from the synergetic effect between the alloy nanoparticles and the pretreated CNTs, were three times higher than those of the unsupported MNi4.8Sn0.2 (M=La, Nd) alloys under the same conditions. XRD and TEM revealed that the alloy particles were uniformly dispersed on the CNTs and the average particle size was ca. 30 nm. The composites also showed good stability and the hydrogen storage capacity decreased by less than 6% after 100 adsorption-desorption cycles. Moreover, no noticeable change in crystalline structure was observed for the composites.
Oxygen-contact charge transfer complexes in organic bicomponent systems
Junmin Zhu,Zhengping Liu,Weixiao Cao,Xinde Feng
Chinese Science Bulletin , 1998, DOI: 10.1007/BF02883375
Abstract: The O2-CCT absorption spectra of bicomponent systems were measured. The influences of various organic compounds as well as the component concentration on the O2-CCT formation ability were investigated. The results show that if the difference of O2-CCT formation ability between the two components is rather large, such as the benzene/ isopropyl ether system, only the O2-CCT absorption of benzene appears, which arises from its higher O2-CCT formation ability. If the difference of O2-CCT formation ability is small, such as the isopropyl ether/ethanol system and the dioxane/isopropyl ether system, it is rather easy to form a dynamic equilibrium of two O2-CCT between the two components, then only one absorption peak appears in the whole concentration range as a result of the repeated addition of the two kinds of O2-CCT absorption. If the difference of O2-CCT formation ability is in medium compared with the two cases above, such as the dioxane/ethanol system, there are two kinds of2-CCT absorption of dioxane and ethanol in the same system in the form of an equilibrium, then two absorption peaks can be detected in the middle concentration range as a result of the repeated addition of the two kinds of2-CCT absorption.
BHAVIOUR OF COMPLEX ELASTIC MODULUS AND INTERNAL FRICTION DURING EUTECTOID DECOMPOSITION
共析转变过程中内耗与复模量行为的对比

LIU Junmin,ZHANG Jinxiu,
刘军民
,张进修

金属学报 , 1996,
Abstract: The dynamically mechanical properties of Zn-22%Al alloys were measured with the low-frequency forced vibration mode by systematically changing the temperature varing rate and vibration frequency during eutectoid decomposition process. The experimental results indicated that the loss elastic modulus had different temperature varying rate and vibration frequency dependent behaviour from the storage elastic modulus, and the dependence of internal friction on temperature varying rate and vibration frequency has been discussed in the viewpoint of the complex elastic modulus. To analyse the complex elastic modulus may be more helpful to study the first-order phase transition than to only analyse internal friction.
Regression Modeling of Baseflow and Baseflow Index for Michigan USA
Yinqin Zhang,Laurent Ahiablame,Bernard Engel,Junmin Liu
Water , 2013, DOI: 10.3390/w5041797
Abstract: Baseflow plays an important role in maintaining streamflow. Seventeen gauged watersheds and their characteristics were used to develop regression models for annual baseflow and baseflow index (BFI) estimation in Michigan. Baseflow was estimated from daily streamflow records using the two-parameter recursive digital filter method for baseflow separation of the Web-based Hydrograph Analysis Tool (WHAT) program. Three equations (two for annual baseflow and one for BFI estimation) were developed and validated. Results indicated that observed average annual baseflow ranged from 162 to 345 mm, and BFI varied from 0.45 to 0.80 during 1967–2011. The average BFI value during the study period was 0.71, suggesting that about 70% of long-term streamflow in the studied watersheds were likely supported by baseflow. The regression models estimated base?ow and BFI with relative errors (RE) varying from ?29% to 48% and from ?14% to 19%, respectively. In absence of reliable information to determine groundwater discharge in streams and rivers, these equations can be used to estimate BFI and annual base?ow in Michigan.
Observation of sub-Doppler absorption in the /Lambda-type three-level Doppler-broadened cesium system
Junmin Wang,Yanhua Wang,Shubin Yan,Tao Liu,Tiancai Zhang
Physics , 2003, DOI: 10.1007/s00340-003-1353-x
Abstract: Thanks to the atomic coherence in coupling laser driven atomic system, sub-Doppler absorption has been observed in Doppler-broadened cesium vapor cell via the /Lambda-type three-level scheme. The linewidth of the sub-Doppler absorption peak become narrower while the frequency detuning of coupling laser increases. The results are in agreement with the theoretical prediction by G. Vemuri et al.[PRA,Vol.53(1996) p.2842].
Cilia and ciliopathies: From Chlamydomonas and beyond
JunMin Pan
Science China Life Sciences , 2008, DOI: 10.1007/s11427-008-0071-3
Abstract: The biological function of motile cilia/flagella has long been recognized. The non-motile primary cilium, once regarded as a vestigial organelle, however, has been found recently to play unexpected roles in mammalian physiology and development. Defects in cilia have profound impact on human health. Diseases related to cilia, collectively called ciliopathies include male infertility, primary cilia dyskinesia, renal cyst formation, blindness, polydactyly, obesity, hypertension, and even mental retardation. Our current understanding of cilia and ciliopathies has been fueled by basic research employing various model organisms including Chlamydomonas, a unicellular green alga. This review article provides a general introduction to the cell biology of cilia and an overview of various cilia-related diseases.
Pool-formation and secondary change of biodegraded viscous oils: Case study of reservoir section in the Zhengjia-Wangzhuang Oilfield, Jiyang Depression
Zhenqi Wang,Ping’an Peng,Chiling Yu,Hong Lu,Yanrong Zou,Linye Zhang,Junmin Liu
Chinese Science Bulletin , 2004, DOI: 10.1007/BF02890452
Abstract: It is demonstrated by various geochemical indexes that the Zhengjia-Wangzhuang Oilfield with viscous crude oil in the Jiyang Depression has been sourced from the contribution of matured source rocks in the upper Es4. The principal cause leading to the densification of crude oils would be biodegradation, with the degradation level of crude oils being ranked as 2–8; vertically, the biodegradation level increases from the top to bottom of the oil column, with a distinctive biodegradation gradient occurring. Calculated parameters of sterane, terpane and methyl-phenanthrene have indicated that the source-rock’s maturity of crude oils and asphaltic sands ranges from 0.7 to 0.9, and based on the calculation of Easy Ro model, the temperature of hydrocarbon generation in the source rock would be within 120–140°C, which coincides with the measurements of reservoir inclusions. The measured homogenization temperature would represent the generation temperature of the source rock, and be fairly different from that of reservoir while being charged with hydrocarbons, which reflects the hydrocarbon-charging to be a fast process, and the period of pool-formation to be consistent with that of peaked generation. According to the evaluation of generation history, the pool-formation could have been occurring in 7–15 Ma. And the biodegradation of crude oils in the study area would be considered to take place in 4–15 Ma based on the examination of biodegradation order and dynamic calculations.
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