检索结果-南通市图书馆

Reactive adsorption of thiophene on Ni/ZnO adsorbent:Effect of ZnO textural structure on the desulfurization activity

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2010年第3期19卷 327-332页

作者： Jingcheng Zhang Yunqi liu Shuang Tian yongming Chai Chenguang liu State Key Laboratory of Heavy Oil Processing Key Laboratory of Catalysis CNPC China University of Petroleum Qingdao 266555 Shandong China

To better understand the nature of reactive adsorption of thiophene on Ni/ZnO adsorbent,the effect of ZnO textural structure on the desulfurization activity was *** materials were synthesized by low-temperature solid-state reaction and the corresponding Ni/ZnO adsorbents were prepared by incipient impregnation *** analysis results showed that the crystalline sizes of ZnO as-synthesized as well as the BET surface areas varied obviously with the calcination *** activity evaluations indicated that the Ni/ZnO adsorbents prepared with ZnO possessed a favorable textural structure as active component exhibited good activity of removing *** evolutions of the main crystalline phases of Ni/ZnO adsorbents before and after reaction confirmed that ZnO played a crucial role in taking up S element and converting it into ZnS in the reactive adsorption *** was concluded that ZnO with larger surface area and smaller crystal particles resulted in better desulfurization activity,which may be the main reason for the different activities of the Ni/ZnO adsorbents prepared with ZnO calcined at different temperatures.

关键词： Ni/ZnO reactive adsorption textural structure low-temperature solid-state reaction thiophene

NiMo/Al_2O_3 catalyst containing nano-sized zeolite Y for deep hydrodesulfurization and hydrodenitrogenation of diesel

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2011年第4期20卷 441-448页

作者： Hailiang Yin Tongna Zhou Yunqi liu yongming Chai Chenguang liu State Key Laboratory of Heavy Oil Processing Key Laboratory of Catalysis CNPC China University of Petroleum Qingdao 266555 Shandong China

Two mixed-matrix NiMo/Al2O3 catalysts containing nano-and micro-sized zeolite Y have been prepared to explore the size effect of zeolite Y particle on the hydrodesulfurization（HDS）and hydrodenitrogenation（HDN）activities of fluid catalytic cracking（FCC）*** were characterized by SEM,BET,XRD,H2-TPR,NH3-TPD and *** results show that the catalyst containing nano-sized zeolite Y possesses larger average pore diameter,higher pore volume,weaker and lesser acid sites,more easily reducible metal phases,shorter MoS2 slabs and more slab layers than the catalyst containing micro-sized zeolite *** catalysts were also evaluated with a high-pressure fixed-bed reactor using real FCC diesel as *** results display that the catalyst containing nano-sized zeolite Y bears higher HDS and HDN activities and exhibits higher relative rate constant for the removal of total sulfur or nitrogen than the one containing micro-sized zeolite.

关键词： zeolite Y nano-sized zeolite micro-sized zeolite hydrodesulfurization hydrodenitrogenation diesel

Synthesis, Characterization and Thermal Decomposition Mechanism of Cetyltrimethyl Ammonium Tetrathiotungstate

在线全文

学校读者我要写书评

暂无评论

Journal of Natural Gas Chemistry 2006年第2期15卷 127-133页

作者： Gaojun An Yunqi liu yongming Chai Hongyan Shang Chenguang liu State Key Laboratory of Heavy Oil Processing Key Laboratory of Catalysis CNPC China University of Petroleum Dongying 257061 China

The synthesis, characterization and thermal decomposition mechanism of cetyltrimethyl ammonium tetrathiotungstate （CTriMATT） were studied herein. The as-synthesized CTriMATT was characterized by Elemental analysis, X-ray diffraction （XRD）, Fourier transform infrared （FT-IR）, Ultraviolet visible （UV-Vis） spectra. The results showed that the as-synthesized CTriMATT had high purity and good crystallinity. The introduction of alkyl groups induced a shift of the stretching vibration band of W-S bond to lower wavenumber, while it had no influence on the position of WS4^2-. Thermogravimetric analysis （TG）, differential thermal analysis （DTA） and in situ XRD characterizations revealed that CTriMATT began to decompose at 423 K in nitrogen and was converted to WS2 eventually. In addition, the decomposition product of CTriMATT at 673 K in nitrogen was characterized by N2 adsorption （BET） and scanning electron microscopy （SEM）. The results demonstrated that WS2 with higher specific surface area, and pore volume could be obtained from the thermal decomposition of CTriMATT in nitrogen.

关键词： cetyltrimethyl ammonium tetrathiotungstate synthesis characterization thermal decomposition mechanism alkyl-substituted

Sintering process and grain growth of Mn-Zn ferrite nanoparticles

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第Z1期25卷 526-530页

作者： WANG Xin CUI Yinfang WANG yongming HAO Shunli liu Chunjing School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China School of Material Science and Engineering Hebei University of Technology Tianjin 300130 China

The density, microstructure and magnetic properties of non-doped Mn-Zn ferrite nanoparticles sintered compacts were investigated. The compacts of non-doped Mn-Zn ferrite nanoparticles were sintered by segmented-sintering process at lower sintering temperature. The density of sintered samples was measured by Archimedes method, and the phase composition and microstructure were examined by XRD and SEM. The sintered Mn-Zn ferrite magnetic measurements were carried out with Vibrating Sample. The results show that the density of sintered compacts increases with the rising of sintering temperature, achieving 4.8245 g·cm-3 when sintered at 900 ℃, which is the optimal density of Mn-Zn functional ferrite needed and from the fractured surface of sintered samples, it can be seen that the grain grows well with small grain size and homogeneous distribution.

关键词： Mn-Zn ferrite sintering temperature grain growth density magnetic properties

Concurrent fatigue crack growth simulation using extended finite element method

在线全文

学校读者我要写书评

暂无评论

Frontiers of Structural and Civil Engineering 2010年第3期4卷 339-347页

作者： Zizi LU yongming liu Civil Engineering Department Clarkson UniversityPotsdamNY 13699USA

In this paper,a concurrent simulation framework for fatigue crack growth analysis is proposed using a novel small time scale model for fatigue mechanism analysis and the extended finite element method(X-FEM)for fatigue crack growth *** proposed small time scale fatigue model does not require the cycle counting as those using the classical fatigue analysis methods and can be performed concurrently with structural/mechanical *** X-FEM greatly facilitates crack growth simulation without remeshing requirements ahead of the crack tip as in the classical finite element *** basic concept and theory of X-FEM was briefly introduced and numerical predictions of stress intensity factors are verified with reference solutions under both uniaxial and multiaxial *** small time scale fatigue model is integrated into the numerical simulation algorithm for concurrent fatigue crack growth *** predictions are compared with available experimental observations for model validation.

关键词： small time scale model extended finite element method(X-FEM) crack growth multiaxial

Optimal time point for the transplantation of neural stem cells induced to differentiate with retinoic acid

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2011年第16期6卷 1243-1247页

作者： Shuxin Wang Dengji Pan Na liu yongming liu Juan Chen Houjie Ni Zhouping Tang Department of Neurology Tongji Hospital Tongji Medical College Huazhong University of Science and Technology Wuhan 430030 HubeiProvince China

Previous studies have demonstrated that differentiated neural stem cells （NSCs） are more suitable for transplantation than non-differentiated NSCs. In this study, NSCs were expanded in vitro for two passages, induced with retinoic acid to differentiate, and harvested between 1 6 days later. They were subsequently cultured in artificial cerebrospinal fluid for an additional 3 days, dudng which their growth and morphology was monitored. NSCs induced for 4 days exhibited a peak rate of cells differentiating into neurons and robust growth. Our results indicate that the optimal time point for transplanting NSCs is following a 4-day period of induced differentiation.

关键词： neural stem cells retinoic acid artificial cerebrospinal fluid induced differentiation cell transplantation optimal time point neural regeneration

Spectroscopic Investigation of the Interaction between Human Serum Albumins and 10-Hydroxycamptothecin

在线全文

学校读者我要写书评

暂无评论

Wuhan University Journal of Natural Sciences 2009年第3期14卷 257-261页

作者： LI Guizhi liu yongming College of Chemistry Yantai University Yantai 264005Shandong China

The binding reaction between 10-hydroxycamptothecin （10-HCPT） and human serum albumins （HSA） is studied by means of fluorescence spectroscopy, UV-Vis absorption spectrum, IH NMR spectrum, and molecular simulation. The results indicate that the binding reaction of 10-HCPT and HSA is a single static quenching process, and the binding equilibrium constant for 10-HCPT binding with HSA is estimated K0-4.93×10^4 L · mol-I at 25 ℃ with the molar ratio of I ： 1. The distance （r） and energy transfer efficiency（E） between donor （HSA） and acceptor （10-HCPT） are obtained as follows, r=3.51 nm; E-0.27. The enthalpy change （△Hφ） and entropy change （△Sφ） are calcu- lated at different temperatures, and the hydrophobic force and shidipole force are the functions in the reaction. The results show that 10-HCPT binds within the subdomain II A of HSA by the hydrophobic force, and the 10-OH and 20-OH of 10-HCPT bind with both residue Leu-238 of HSA and Ala 291 of HSA by hydrogen bonds.

关键词： 10-hydroxycamptothecin human serum albumins (HSA) fluorescence spectroscopy UV absorption spectroscopy 1H NMR spectrum molecular simulation

Preparation and properties of nanosize MnZn ferrite from δ-FeOOH

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2006年第Z1期25卷 466-470页

作者： HAO Shunli WANG Xin WEI Yu Wang yongming liu Chunjing School of Material and Engineering Hebei University of Technology Tianjin 300130 China 　 College of Chemistry Hebei Normal University Shijiazhuang 050016 China 　　

Ferrous ion was transformed into feroxyhyte (δ-FeOOH) by oxidation. Then, manganese sulfate and zinc sulfate in some ratio were added to the feroxyhyte solution. The co-precipitation was boiling reflux conditions sometime under constant stirring. The nanosize MnZn ferrite powder was formed. The mechanism of preparation of the nanosize MnZn ferrite was discussed, and the formation of feroxyhyte which was playing a key role during the process was mentioned. The properties of powder was tested by means of X-ray diffraction, transmission electron microscopy and vibrating sample magnetometer. The results show that the samples of spherical particles about 20 nm, which have characteristics of ferrimagnetism, has larger saturation magnetization, but the remanent magnetization and coercivity are comparatively smaller. The spinel MnZn ferrite nanosize powder was successfully prepared from δ-FeOOH at low temperature, with low-carbon steel and peroxide as main material.

关键词： nanosize MnZn ferrite feroxyhyte preparation characterization

在线全文

学校读者我要写书评

暂无评论

膳食硝酸盐的心血管系统保护机制研究进展

实用心脑肺血管病杂志 2025年第1期33卷 117-120页

作者：钱林陈丽蓉赵佳敏刘永铭兰州大学第一临床医学院甘肃省兰州市730030 兰州大学第一医院老年心血管科甘肃省兰州市730030 甘肃省老年疾病临床医学研究中心甘肃省兰州市730030

流行病学研究证明,增加蔬菜摄入量可以降低心血管疾病的风险。近年来,主要来源于膳食的硝酸盐对心血管系统的保护作用引起了广泛关注。本文通过回顾相关文献,综述了膳食硝酸盐的心血管系统保护机制,包括降低血压、改善内皮功能、抑制血... 详细信息

流行病学研究证明,增加蔬菜摄入量可以降低心血管疾病的风险。近年来,主要来源于膳食的硝酸盐对心血管系统的保护作用引起了广泛关注。本文通过回顾相关文献,综述了膳食硝酸盐的心血管系统保护机制,包括降低血压、改善内皮功能、抑制血小板聚集、减轻心肌缺血再灌注损伤(IRI)、降低肺动脉压,提出膳食硝酸盐可用于心血管疾病患者的膳食治疗。

关键词：心血管疾病硝酸盐类膳食综述