检索结果-南通市图书馆

Preparation of Ultralow Molecular Weight Poly(vinyl chloride) with Submicrometer Particles via Precipitation Polymerization

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Polymer Science 2019年第7期37卷 646-653页

作者： Peng Cui Chang-Tong Song Xian-Hong Zhang Dong Chen Yu-Hong Ma Wan-Tai Yang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China College of Material Science and Engineering Beijing University of Chemical TechnologyBeijing 100029China

Poly(vinyl chloride), with ultralow molecular weight, produced by free radical polymerization either at high temperature or in the presence of chain transfer agents, is widely used as special resins and polymer process additives. This paper reports a new process, called self-stabilized precipitation polymerization, in which the polymerization of vinyl chloride monomer (VCM) is conducted in hydrocarbon diluents without addition of any suspending agent or emulsifier. The merits of this novel strategy include:(1) PVC resins with ultra-low number-average molecular weight (Mn) from 4000 to 15000, which is much lower than Mn of those prepared by conventional suspension and emulsion polymerizations,(2) sub-micrometer PVC particles with near spherical morphology, and (3) the very simple post-polymerization separation process. Under mild stirring, polymerization proceeds stably and smoothly. The influences of main process factors, such as solvents, initiator and monomer concentrations, polymerization time, and temperature on both particle morphology and Mn of the polymer products are investigated systematically. The molar ratio of-CH2-CHCl-/-CH=CH-CH2CHCl, a good indicator of structural defects, is about 1000/0.1 which means the low molecular weights do not result from chain transfer to the monomers. Then the mechanism of this polymerization is proposed. In summary, this novel polymerization technology provides a straightforward method for preparing PVC particulate products with low Mn.

关键词： Precipitation polymerization Vinyl chloride Ultralow molecular weight Pure product

Acid precipitation coupled electrodialysis to improve separation of chloride and organics in pulping crystallization mother liquor

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Chemical Engineering 2019年第12期27卷 2917-2924页

作者： Zhaoyang Li Rongzong Li Zhaoxiang Zhong Ming Zhou Min Chen Weihong Xing State Key Laboratory of Materials-Oriented Chemical Engineering National Engineering Research Center for Special Separation MembraneNanjing Tech UniversityNanjing 211816China

Inefficient separation of inorganic salts and organic matters in crystallization mother liquor is still a problem to industrial wa stewater treatment since the high salinity significantly impedes organic pollutant degradation by oxidation or *** the study,acidification combined electrodialysis(ED)was attempted to effectively separate Cl-ions from organics in concentrate pulping ***’s rejection rate to total organic carbon(TOC)was 85%at wastewater intrinsic pH=9.8 and enhanced to 93%by acidifying it to pH=2 in ED ***-charged alkaline organic compounds(mainly lignin)could be liberated from their sodium salt forms and coagulated in acidification *** of the organic substances also made their electro-migration less effective under electric driving force and in particular improved separation efficiency of chloride and *** acid-ED coupled treatment(pH=2 and J=40 mA·cm-2)[TOC]remarkably reduced from 1.315 g·L-1 to 0.048 g·L-1 and[Cl-]accumulated to 130 g·L-1 in concentrate *** rate of NaCl was 89%and the power consumption was 0.38 kW·h·kg-1 *** fouling was not caused as electric resistance of membrane pile maintained *** conclusion,acidic-ED is a practical option to treat salinity organic wastewater when current techniques including thermal evaporation and pressure-driven membrane se paration present limitations.

关键词： Crystallization mother liquor Acid precipitation Electrodialysis chloride recovery

chloride channel-dependent copper acquisition of laccase in the basidiomycetous fungus Cryptococcus neoformans

在线全文

学校读者我要写书评

暂无评论

Science China(Life Sciences) 2010年第1期53卷 125-130页

作者： ZHU ChangWei1,JIANG Nan1,XIAO DongGuang2,PAN Jiao1 & ZHU XuDong1 1 State Key Program of Microbiology and Department of Microbiology,College of Life Sciences,Nankai University,Tianjin 300071,China 2 Tianjin Industrial Microbiology Key Lab,College of Bioengineering,Tianjin University of Science & Technology,Tianjin 300457,China 1. State Key Program of Microbiology and Department of Microbiology College of Life Sciences Nankai University Tianjin 300071 China2. Tianjin Industrial Microbiology Key Lab College of Bioengineering Tianjin University of Science & Technology Tianjin 300457 China

The CLC chloride channel gene CLC-A of the pathogen yeast Cryptococcus neoformans was previously reported to be critical for multicopper laccase activity and growth at an elevated *** study reports that copper homeostasis was impaired in the clc-a *** was demonstrated by the substantial decrease of the intracellular quantity of copper under copper-limited growth as determined by flame atomic absorption ***-A is a critical factor in copper homeostasis which is required for copper acquisition of laccase in ***.

关键词： chloride channel laccase copper homeostasis Cryptococcus neoformans

Synchronous removal of CuO nanoparticles and Cu2+ by polyaluminum chloride-Enteromorpha polysaccharides: Effect of Al species and pH

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2020年第2期32卷 1-11页

作者： Yuanxia Luo Baoyu Gao Jie Wang Qinyan Yue Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and EngineeringShandong University266000 QingdaoChina

Copper oxide nanomaterials have been extensively applied and can have serious impacts when discharged into the aquatic environment, especially when complexed with humic acid(HA) to form composite *** an innovative recycled coagulant aid,Enteromorpha polysaccharides(Ep) were associated with polyaluminum chloride(PACl)(denoted as PACl-Ep) to simultaneously remove CuO nanoparticles, Cu2+and HA in this *** influence of different Al species coagulants(AlCl3, PAClb and PAClc) and water pH on coagulation performance, floc properties and reaction mechanisms was investigated in *** showed that in the three PACl-Ep systems, PAClb-Ep gave the highest removal efficiencies for turbidity and Cu2+, and the best UV254 removal effect was reached by using *** contents of Alb and Alc contributed to great coagulation performance because of their stronger bridging and sweeping *** all the Al species coagulants, alkalescent conditions were more conducive to removing Cu and HA compared to acidic ***, smaller and more agminated flocs with great recovery ability were formed by PAClb-Ep and PAClc-Ep systems(bridging and enmeshment effects cooperated with the chelated reticular structure formed by the Ep and Al species).Similarly,due to the increased hydrolysis and hydroxide precipitates, flocs formed under the condition of alkalescence were smaller, denser and stronger compared with weakly acidic conditions.

关键词： Al species Enteromorpha polysaccharides Polyaluminum chloride 27Al nuclear magnetic resonance Simultaneous removal

Effects of chloride on electrochemical and stress corrosion cracking behavior of 9Cr ferritic-martensitic steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2020年第6期27卷 719-731页

作者： Zhen Zhang Zheng-fei Hu Liang He Xiao-bo Zhang Xin-xian Fang Bao-sen Zhang Zhi-xin Ba Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology Nanjing 211167JiangsuChina School of Materials Science and Engineering Nanjing Institute of TechnologyNanjing 211167JiangsuChina School of Materials Science and Engineering Tongji UniversityShanghai 201804China School of Materials Science and Engineering Georgia Institute of TechnologyAtlanta 30332-0620USA

The electrochemical and stress corrosion cracking behavior of 9Cr ferritic-martensitic steel is investigated in the chloride environment by using the traditional electrochemical method, the scanning vibrating electrode technique and the slow strain rate test (SSRT). Results of the static corrosion tests and corrosion morphology show that the prior austenite grain boundaries and martensite lath boundaries are the preferred sites for pit nucleation and growth in chloride environment. Results of SSRT coupled with insitu electrochemical test show that the transition from pitting corrosion to uniform corrosion, as well as the nucleation of stress corrosion crack, is the synergistic effects of the chloride and applied load. Stress corrosion cracking of the steel in the chloride environment can be divided into three different regions as follows: fast and uniform corrosion activ-ity, microcrack nucleation and propagation, and active crack growth regions.

关键词： 9Cr ferritic-martensitic steel chloride In situ electrochemical test Scanning vibrating electrode technique Stress corrosion cracking

Extraction and separation of yttrium from other rare earths in chloride medium by phosphorylcarboxylic acids

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

Journal of Rare Earths 2022年第6期40卷 958-964,I0004页

作者： Guolong Wu Zhifeng Zhang Yanling Li Wuping Liao State Key Laboratory of Rare Earth Resource Utilization Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchun 130022China University of Science and Technology of China Hefei 230026China Ganjiang Innovation Academy Chinese Academy of SciencesGanzhou 341000China

Two phosphorylcarboxylic acids,3-((bis(2-ethylhexyloxy))phosphoryl)propanoic acid(PPA) and 3-((bis(2-ethylhexyloxy))phosphoryl)-3-phenylpropanoic acid(PPPA),were synthesized for separating yttrium from other rare earths in the chloride feed of ion-adsorption type rare earth *** effect of the factors such as pH_(1/2),temperature,saponification degree and phase modifiers was *** separation efficiencies of PPA and PPPA are obviously better than the typical extractants such as sec-octylphenoxy acetic acid(CA-12) and naphthenic acid(NA).The extraction process of rare earths by PPA and PPPA is a cation exchanging reaction,which is similar to those of CA-12 and *** loaded rare earths in both PPA and PPPA systems can be effectively back-extracted by 0.5 mol/L HCl or higher concentration.A cascade extraction process for separating yttrium from other rare earths was developed using PPPA as the *** yttrium product with the purity of 97.20 wt% was obtained by 35 stages of extraction and 12 stages of scrubbing.

关键词： Phosphorylcarboxylic acids Extraction Separation Yttrium chloride Ion-adsorption type rare earth concentrate

Strategies of selective electroreduction of aqueous nitrate to N_(2) in chloride-free system:A critical review

在线全文

学校读者我要写书评

暂无评论

Green Energy & Environment 2024年第2期9卷 198-216页

作者： Fukuan Li Weizhe Zhang Peng Zhang Ao Gong Kexun Li College of Environmental Science and Engineering Nankai UniversityTianjin300350China MOE Key Laboratory of Pollution Processes and Environmental Criteria Tianjin Key Laboratory of Environmental Remediation and Pollution ControlTianjin Key Laboratory of Environmental Technology for Complex Trans-Media PollutionNankai UniversityTianjin300350China

Electroreduction of nitrate has been gaining wide attention in recent years owing to it's beneficial for converting nitrate into benign N_(2) from the perspective of electrocatalytic denitrification or into value-added ammonia from the perspective of electrocatalytic NH_(3) *** reason of the undesired formation of ammonia is dominant during electroreduction of nitrate-containing wastewater,chloride has been widely used to improve N_(2) ***,selective electroreduction of nitrate to N2 gas in chloride-containing system poses several *** this review,we focus on the key strategies for efficiently enhancing N_(2) selectivity of electroreduction of nitrate in chloride-free system,including optimal selection of elements,combining an active metal catalyst with another metal,manipulating the crystalline morphology and facet orientation,constructing core–shell structure catalysts,*** summarizing the strategies,four possible reaction pathways of electro-reduction of nitrate to N_(2) are ***,this review attempts to provide practical strategies for enhancing N2 selectivity without the aid of electrochlorination and highlight directions for future research for designing appropriate electrocatalyst for final electrocatalytic denitrifi-cation.

关键词： Nitrate chloride Electroreduction Selectivity Nitrogen

Enhancements of Passive Film and Pitting Resistance in chloride Solution for 316LX Austenitic Stainless Steel After Sn Alloying

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2019年第1期32卷 98-106页

作者： Yuan-Yuan Yang Yuan-Yuan Liu Man-Lang Cheng Nian-Wei Dai Min Sun Jin Li Yi-Ming Jiang Department of Materials Science Fudan University

In the present work, the electrochemical behavior and properties of the passive film of a new Sn-alloyed 316 LX austenitic stainless steel were investigated. With the increase in Sn content in 316 LX austenitic stainless steel from 0 to 0.21%, the critical pitting temperature value increased from 32.6 to 38.8 °C, and the pitting potential increased from 0.252 V_(SCE) to 0.317 V_(SCE). Electrochemical impedance spectroscopy results showed that the corrosion resistance of passive film rose with the increase in Sn content, indicating a more stable passive film. The Mott–Schottky measurement revealed an n-type passive film with a decreased carrier concentration on the 316 LX austenitic stainless steel surface. The Cr, Sn^(2+) and Sn^(4+)(SnO, SnOHCl or SnO_2) enrichments were observed in the passive layer by X-ray photoelectron spectroscopy. The enrichment of Sn and Cr in the passive film can account for the enhanced pitting resistance of 316 LX austenitic stainless steel in chloride solution.

关键词： Austenitic stainless steel Sn alloying Pitting chloride solution

Influence of Rust Layers on the Corrosion Behavior of Ultra-High Strength Steel 300M Subjected to Wet–Dry cyclic Environment with chloride and Low Humidity

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2015年第2期28卷 139-146页

作者： Qiang Guo Jian-Hua Liu Mei Yu Song-Mei Li Key Laboratory of Aerospace Materials and Performance(Ministry of Education) School of Materials Science and Engineering Beihang University

The influence of rust layers on the corrosion behavior of ultra-high strength steel 300M subjected to a simulated coastal atmosphere was investigated by corrosion weight loss, surface analysis techniques, and electrochemical methods. The results exhibit the presence of a large proportion of γ-FeOOH and α-FeOOH and a small amount of Fe3O4 in the outer rust layer. During the wet-dry cyclic process, the bonding performance and the density of outer rust layer deteriorate with the thickness of outer rust. The inner rust layer plays a main role on protectiveness, which can be attributed to the formation of an ultra-dense and adherent rust film with major constituent of α-FeOOH and α-Fe2O3 on the steel.

关键词： Ultra-high strength steel Wet-dry chloride Corrosion Rust