检索结果-南通市图书馆

A MOF built on 8-connected Y3 nodes demonstrates simultaneous reverse adsorptive separation: ethane over ethylene and propane over propylene

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

Science China Chemistry 2024年第11期67卷 3657-3661页

作者： Lu-Lu Ma Jiaqi Liu Kang Zhou Zixuan Cao Jiafeng Miao Guo-Ping Yang Yao-Yu Wang Jing Li Hao Wang Key Laboratory of Synthetic and Natural Functional Molecule Chemistry of the Ministry of Education Shaanxi Key Laboratory of PhysicoInorganic Chemistry College of Chemistry & Materials Science Northwest University Hoffmann Institute of Advanced Materials Shenzhen Polytechnic University Shenzhen Senior High School Department of Chemistry and Chemical Biology Rutgers University

Selective adsorption of paraffins over olefins（mostly C2 and C3） by porous solids could offer tremendous advantages for the purification of olefins, which is, however, challenging as it has stringent requirements on the pore dimensions and pore surface chemistry of the adsorbent. We report here a metal-organic framework（MOF） with novel topology, Y3（μ3-OH）(TCMPB)2(denoted as HIAM-31., TCMPB4-= 1.2,4,5-tetra（4-carboxy-3-methylphenyl）benzene), which shows reversed separation of C2H6/C2H4and C3H8/C3H6simultaneously. The ideal adsorbed solution theory（IAST） selectivities for equimolar binary mixtures of C2H6/C2H4and C3H8/C3H6were calculated to be 1.67 and 1.23 at 1.bar and 298 K for HIAM-31.. Its capability of removing paraffines from paraffin/olefin mixtures is validated by breakthrough measurements. Molecular simulations reveal that the preferential adsorption of paraffins over olefins by HIAM-31. may be attributed to the abundant carboxylate oxygen atoms along its channel.

关键词： metal-organic framework adsorption separation

Metabolism Study on Tobacco-specific N-Nitrosamines in Rabbit by Solid-phase Extraction and Liquid Chromatography-electrospray Ionization-mass Spectrometry Method

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2005年第12期16卷 1633-1636页

作者： Jian Xun ZHANG Chen Chen LI Zheng CHEN Zhi Hua RAO Da Wei WEN Ke An LI Hu Wei LIU college of Chemistry and Molecular {1. Peking University Beijing 100871

Metabolism of four tobacco-specific N-nitrosamines （TSNAs）, N＇-nitrosonornicotine （NNN）, N＇-nitrosoanatabine （NAT）, N＇-nitrosoanabasine （NAB） and 4-（methyl nitrosamino）-1. （3-pyridyl）-1.butanone （NNK） was studied by solid-phase extraction （SPE） and liquid chromato- graphy-electrospray ionization-mass spectrometry （LC-ESI-MS）. SPE and LC-ESI-MS method was evaluated to be rapid, simple, sensitive and selective for analysis of TSNAs in rabbit serum. The doses of TSNAs administrated were 4.666 μg/kg and 1..665 μg/kg according to different levels in cigarettes. Metabolic curves of four TSNAs and 4-（methyl nitrosamino）-1.（3-pyridyl）- 1.butanone （NNAL）, the metabolite of NNK, were obtained.

关键词： Tobacco-specific N-nitrosamines metabolism liquid chromatography-electrosprayinterface-mass spectrometry

Using lightning locating system based on time-of-arrival technique to study three-dimensional lightning discharge processes

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2010年第4期53卷 591-602页

作者： ZHANG GuangShu1.WANG YanHui1.QIE XiuShu2,ZHANG Tong1.ZHAO YuXiang1.3,LI YaJun1.& CAO DongJie1. Laboratory for Climate Environment and Disasters of Western China,Cold and Arid Regions Environmental and engineering Research Institute,Chinese Academy of Sciences,Lanzhou 730000,China 2 Laboratory for Middle Atmosphere and Global Environment Observation(LAGEO),Institute of Atmospheric Physics,Chinese Academy of Sciences,Beijing 1.0029,China 3 Department of Physics,Tianshui Normal {1.,Tianshui 741.01.China 1. Laboratory for Climate Environment and Disasters of Western China Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China2. Laboratory for Middle Atmosphere and Global Environment Observation (LAGEO) Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China3. Department of Physics Tianshui Normal College Tianshui 741001 China

A time-of-arrival(TOA) system based on GPS technology for locating VHF radiation sources from lightning has been developed and used in observation sites in the northern Shandong Province,*** 3D images of the lightning progression have been obtained successfully for the first time in *** 3D-channel evolutions of typical negative CG,positive CG and IC lightning flashes have been discussed together with the data of fast electric field *** was found that significant differences existed between the negative and positive CG lightning flashes in terms of the initiation and propagation of the radiation *** preliminary breakdown of a negative CG lightning flash propagated at a speed about 5.2×1.4 m/*** stepped leader of negative CG lightning flashes was trigged by negative initial ***,it propagated downward at a speed of 1.3×1.5 m/*** initial process of the positive CG lightning flashes was also a propagation process of negative *** streamers propagated dominantly horizontally in the positive charge region and accumulated positive charges at the origin of the lightning,and as a consequence,initiated downward positive streamers.A new type of lightning discharge that was triggered by a narrow bipolar pulse(NBP) is discussed in this *** NBP was originated at altitude of about 1..5 km in the upper positive charge *** a distinct difference from normal IC flash,its channels extended horizontally all around and produced a lot of radiation *** source power of the NBP could approach 1..7 kW,which is much greater than that of normal lightning discharge ranging between 1.0 mW and 500 *** 3D propagation of this new type of lightning discharge was observed and obtained for the first time in *** possible initiation mechanism of this new type of light-ning is discussed here.

关键词： time-of-arrival(TOA) technique three dimensional lightning locating system discharge process narrow bipolar pulse new-type of IC lightning

Preparation and electromagnetic properties of nanosized Co_(0.5)Zn_(0.5)Fe_(2)O_(4) ferrite

在线全文

学校读者我要写书评

暂无评论

Rare Metals 2022年第9期41卷 3228-3232页

作者： Yi-Wei Liu Jing Zhang Lu-Shun Gu Li-Xi Wang Qi-Tu Zhang college of Materials Science and {1. Nanjing Tech UniversityNanjing210009China

Nanosized Co_(0.5)Zn_(0.5)Fe_(2)O_(4) ferrite was prepared by chemical co-precipitation *** samples were characterized by X-ray diffraction(XRD),field-emission transmission electron microscopy(FETEM),vibrating sample magnetometer(VSM)and network *** analysis indicates that the diameter of as-prepared powder is about 20-30 *** saturation magnetization of nanosized Co_(0.5)Zn_(0.5)Fe_(2)O_(4) ferrite is 74.01.mA·m^(2)·g^(−1..The complex permittivity and complex permeability of the Co-Zn ferrite were measured by vector network analyzer in the frequency range of 2.0-1..0 GHz,and the reflection loss(RL)was investigated according to the wave transmission *** results show that the maximum reflection loss reaches−1..7 dB at 6.8 GHz and the bandwidth of reflection loss less than−1. dB reaches 3.8 *** as-prepared nanosized Co_(0.5)Zn_(0.5)Fe_(2)O_(4) ferrite can be potentially used as an excellent microwave absorber in the C-band.

关键词： Nanosized Co-Zn ferrite Chemical co-precipitation method Electromagnetic properties Reflection loss

Optimization for aerodynamic performance of double serpentine nozzles with spanwise offsets using Taguchi-based CFD analysis

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2023年第5期36卷 1-17页

作者： Xuyong ZHANG Yong SHAN Jingzhou ZHANG Zhongcheng WU college of Energy and Power {1. Nanjing University of Aeronautics and AstronauticsNanjing 210016China

Serpentine nozzles are widely used in combat aircraft to realize strong stealth *** on the layout characteristics within a confined space,a series of double serpentine nozzles with spanwise offsets are *** computational fluid dynamics and Taguchi method,the influence mechanisms of the Distribution of Area(DA),Distributions of Centerline for the first and second‘S’sections in the Vertical direction(DCV1.and DCV2),and Distribution of Centerline in the Spanwise direction(DCS)are *** impact of these factors on the total pressure recovery coefficient can be ranked as DA>DCV2>DCS>DCV1.whereas their impacts on the discharge coefficient and axial thrust coefficient can be ranked as DCV2>DCS>DA>*** the statistical significance of these factors,a nozzle in which DA changes rapidly at the exit and DCV1.DCV2,and DCS change rapidly at the entrance gives the best aerodynamic *** to the worst configuration,the total pressure recovery coefficient,discharge coefficient,and axial thrust coefficient are improved by 1.6%,3.5%and 3.6%,*** influences the gas flow acceleration in the entire serpentine channel,resulting in different wall shear stress and friction *** various centerline distributions influence the gas flow acceleration effects and form complex wave structures in the constantarea extension section,resulting in different local and friction losses.

关键词： Aerodynamics Analysis of Variance(ANOVA) Computational Fluid Dynamics(CFD) Double serpentine nozzle Spanwise offset Taguchi methods

The Role of Fe(Ⅱ)in the Contact Glow Discharge Electrolysis

在线全文

学校读者我要写书评

暂无评论

Plasma Science and Technology 2007年第4期9卷 431-435页

作者：高锦章郭晓马东平杨武 college of Chemistry and Chemical {1. Northwest Normal UniversityLanzhou 730070China

In this paper, we use methyl violet as a model organic substrate in wastewater to study the effect of Fe（Ⅱ） ion on the contact glow discharge electrolysis （CGDE）. The decoloration rate and the COD （Chemical Oxygen Demand） value have been examined. It is found that the presence of Fe（Ⅱ） ion can accelerate obviously the degradation of methyl violet, because it reacts with H2O2 in the CGDE process to yield hydroxyl radical, just acting as a Fenton-like reagent. Moreover, the optimal conditions for decoloring methyl violet were obtained, by means of an orthogonal experiment, to be [Fe^2＋] =1.1.^-3 mol/L, applied voltage of 700 V of and pH = 9.0.

关键词： oxidation contact glow discharge electrolysis Fenton-like reagent methyl violet

Syntheses,Structures and Luminescent Properties of Cd(Ⅱ)/Zn(Ⅱ) Coordination Polymers Based on the Flexible 4-Substituted Bis(1.2,4-triazole) Ligand

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2017年第7期36卷 1156-1163页

作者：彭艳芬刘天宝吴秋艳 college of Chemical and Material {1. Chizhou University Chizhou 247000 China

Two new cadmium（II） and zinc（II） coordination polymers, {[Cd（btre）0.5- （mip）（H2O）2]·H2O}n （1. and [Zn（btre）（mip）]n （2）, were synthesized at room temperature condition and characterized by IR spectra, elemental analyses, single-crystal and powder X-ray diffractions （btre = 1.2-bis（1.2,4-triazol-4-yl）ethane, H2mip = 5-methyl-1.3-benzenedicarboxylic acid）. Complex 1.belongs to the triclinic system, P space group, with a = 8.9830（6）, b = 1..0579（6）, c = 1..2479（9） , α = 98.837（6）, β = 1.5.975（8）, γ = 1.6.370（6）°, V = 756.30（1.） 3 and Z = 2; complex 2 crystallizes in monoclinic, space group P21.c, with a = 7.0332（3）, b = 1..9947（7）, c = 1..9689（7）？, β = 97.1.70（1.）°, V = 1.71.1.（1.）？3 and Z = 4. Compounds 1.and 2 based on the same N/O-donor ligands show different structures. The one-dimensional chains of 1.are further linked by hydrogen bonding and π-π interactions to yield a three-dimensional supramolecular structure. The two-dimensional （6,3） networks of 2 are further extended into a 3D framework via π-π interactions. Thermal stabilities and luminescence of 1.and 2 were investigated.

关键词： 1.2-bis(1.2,4-triazol-4-yl)ethane 2D (6,3) network luminescence coordination polymer

Si-doped composite carbon as anode of lithium ion batteries

在线全文

学校读者我要写书评

暂无评论

中国有色金属学会会刊：英文版 2003年第5期13卷 1062-1065页

作者：郭华军李新海王志兴彭文杰郭永兴 college of Metallurgical Science and {1. Central South University Changsha 410083 China

Si doped composite material was prepared by coating artificial graphite with the mixture of phenol resin and polysilicone and following with heat treatment at 1.050 ℃ in an argon gas atmosphere. The structure and characteristics of the composite carbon were determined by means of XRD, SEM, BET surface area and electrochemical measurements. The new carbon material has a disordered carbon/graphite composite structure, with silicon doped in the disordered carbon. Compared with the pristine graphite, the electrochemical performance is improved for the Si doped composite carbon with large reversible capacity of 31..6 mAh/g, high initial charge/discharge efficiency of 88.61., and excellent cycle stability. The prototype batteries using the composite carbon as anode material have large discharge capacity of 845 mAh and high capacity retention ratio of 95.80% at the 200th cycle.

关键词：锂离子电池碳阳极掺硅

One-pot synthesis and structural characterization of urea-isobutyraldehyde-formaldehyde resin

在线全文

学校读者我要写书评

暂无评论

Journal of Central South University 2009年第1期16卷 80-84页

作者：张一甫曾幸荣 college of Materials Science and {1. South China University of Technology

Urea-isobutyraldehyde-formaldehyde (UIF) resin was synthesized from urea, isobutyraldehyde, and formaldehyde using sulfuric acid as a catalyst by one pot method. The effects of molar ratios of isobutyraldehyde to formaldehyde (n(I)/n(F)) and aldehyde to urea (n(A)/n(U)) on the yield, hydroxyl value (vs KOH) and softening point of the resin were investigated. The structure of the resin was characterized by FT-IR, 1.-NMR and 1.C-NMR. The results show that when the molar ratio of urea to isobutyraldehyde to formaldehyde (n(U)/n(I)/n(F)) is 1.0/3.0/3.0, the yield UIF resin is 67.1., and the softening point and hydroxyl value are 88 ℃ and 37 mg/g, respectively. The FT-IR, 1.-NMR and 1.C-NMR results show that the lactam is formed by aminomethylation from urea, isobutyraldehyde, and formaldehyde.

关键词： urea isobutyraldehyde formaldehyde resin synthesis structural characterization