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Characteristic and mechanism of Cr(Ⅵ) adsorption by ammonium sulfamate-bacterial cellulose in aqueous solutions

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Chinese Chemical Letters 2013年第3期24卷 253-256页

作者： Min Lu xiao-hui Guan xiao-hui Xu De-Zhou Wei School of Chemical Engineering Northeast Dianli University School of Resources & Civil Engineering Northeastern University

A new adsorbent, ammonium sulfamate-bacterial cellulose （ASBC）, was prepared through chemical modifications of bacterial cellulose. The process of adsorbing Cr（VI） including its isotherm and kinetics, was measured and studied. The results showed that pH value was a very important parameter to the adsorbing efficiency. The adsorption kinetics can be described by a pseudo-second rate model and a particle diffusion equation. Both physical and chemical adsorptions existed in the adsorption process, but chemical adsorption was more dominatant. And particles internal diffusion was not the only rate controlling step. The adsorption equilibrium can be described by the Langmuir type, which indicated that a typical single-molecule layer adsorption of Cr（VI） by ASBC could be described. And the rate of adsorption followed the Slips model well, which indicated that ASBC had some multiphase and asymmetry. The coordination adsorption and ion exchange effect were the main mechanisms of chemical adsorption. The absorbed Cr（V1） can be desorbed effectively by 0.5 mol/L EDTA or HCI from the adsorbent, which could make it be reusable

关键词： Ammonium sulfamate-bacterial celluloseAdsorption characteristicAdsorption mechanismCr(Vl)

Cryoballoon ablation of persistent atrial fibrillation for de novo pulmonary vein isolation:a single-center follow-up study

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Journal of Geriatric Cardiology 2022年第10期19卷 725-733页

作者： Zhong-Jing CAO xiao-Gang GUO Qi SUN Yan-Qiao CHEN Hai-Yang XIE Jian-du YANG hui-Qiang WEI Jia-hui LI Jian MA Department of Cardiology Sichuan Academy of Medical Sciences&Sichuan Provincial People’s HospitalSchool of Medicine UESTCChengduChina State Key Laboratory of Cardiovascular Disease Arrhythmia CenterFuwai HospitalNational Center for Cardiovascular DiseasesChinese Academy of Medical Sciences and Peking Union Medical CollegeBeijingChina Department of Cardiology Guangdong Cardiovascular InstituteGuangdong Provincial People’s HospitalGuangdong Academy of Medical ScienceGuangzhouChina

BACKGROUND Pulmonary vein isolation(PVI)alone for persistent atrial fibrillation(PersAF)remains *** characteristics of cryoballoon ablation(CBA)to treat PersAF and the blanking period recurrence are *** This study retrospectively analyzed patients with PersAF undergoing second-generation CBA for de novo *** post-procedural efficacy and survival analysis were compared between patients with different PersAF *** multivariate Cox regression analysis was used to detect the risk factors for *** and long-term recurrence were analyzed relative to each *** A total of 329 patients were enrolled,with a median PersAF duration of 4.0 months(interquartile range:2.0–12.0 months);257 patients(78.1%)were ***-Meier analysis of freedom from atrial fibrillation recurrence at 12,24,and 30 months showed 71.0%,58.5%,and 54.9%,*** PersAF had a relatively favorable survival rate and a narrow P-wave duration of restoring sinus rhythm compared with that of PersAF lasting more than three months(Pduration and left atrial anteroposterior diameter≥42 mm were the risk factors for atrial fibrillation recurrence after CBA[hazard ratio(HR)=1.89,95%CI:1.01–1.4,P=0.042;HR=3.6,95%CI:2.4–5.4,Pduration and left atrial size were risk factors for atrial fibrillation recurrence after *** period recurrence was associated with long-term recurrence.

关键词： balloon fibrillation atrial

Impact of oxygen supply on production of terpenoids by microorganisms: State of the art

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Chinese Journal of Chemical Engineering 2021年第2期34卷 46-53页

作者： Ting-Ting Liu Han xiao Jian-hui xiao Jian-Jiang Zhong State Key Laboratory of Microbial Metabolism Joint International Research Laboratory of Metabolic and Developmental SciencesLaboratory of Molecular Biochemical Engineering and Advanced Fermentation TechnologyDepartment of BioengineeringSchool of Life Sciences and BiotechnologyShanghai Jiao Tong UniversityShanghai 200240China Zunyi Municipal Key Laboratory of Medicinal Biotechnology Center for Translational MedicineAffiliated Hospital of Zunyi Medical UniversityZunyi 563003China

Terpenoids are a class of high value-added natural products with a variety of biological *** engineered microorganisms,such as those of Escherichia coli and Saccharomyces cerevisiae,have merits in producing plant or fungus-derived terpenoids,due to their mature genetic manipulation,simple nutrient demand and fast ***,as a key environmental factor,is particularly important to microbial metabolism and growth,and suitable oxygen supply is viewed as a prerequisite for realizing highly efficient production of terpenoids by engineered *** this article,the role of oxygen in regulating terpenoid bioproduction is overviewed from the viewpoints of cellular carbon metabolism,energy metabolism and terpenoid *** on adjusting oxygen availability to microorganisms,including genetic modification of cellular metabolism related with oxygen utilization,are summarized and discussed,to provide helpful information for further improvement of terpenoid biosynthesis by microbes.

关键词： Terpenoid Microorganisms Oxygen supply Chassis modification

Coercivity enhancement of hot-deformed Nd-Fe-B magnets with Pr-Cu alloy addition

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Rare Metals 2023年第4期42卷 1403-1407页

作者： Jun-Ming Wang Zhao-hui Guo Zheng Jing xiao du Neng-Jun Yu Meng-Yu Li Ming-Gang Zhu Wei Li Division of Functional Materials Central Iron&Steel Research InstituteBeijing100081China

Effects of low-melting Pr-Cu alloy addition on the microstructure and magnetic properties of the hot-deformation Nd-Fe-B magnets were investigated.A small amount of Pr-Cu addition enhances the coercivity of the hot-deformation Nd-Fe-B magnets *** coercivity of the hotdeformation Nd-Fe-B magnets with 4.0 wt%Pr_(85)Cu_(15)addition increases to 1271 kA·m^(-1),75.69%higher than that of Pr-Cu-free magnet(723 kA·m^(-1)),and then decreases with5 wt%Pr_(85)Cu_(15)*** is observed that there a uniform RE-rich phase is formed wrapping the Nd2Fe14B main phase in the sample with 4.0%Pr_(85)Cu_(15)addition by scanning electron microscopy(SEM),which promotes the *** angular dependence of coercivity for the hot-deformation Nd-Fe-B magnets indicates that the coercivity mechanism is nucleation combined with domain wall *** domain wall pinning is weakened,while the nucleation is enhanced after Pr-Cu ***,intrinsic coercivity,and maximum magnetic energy product of the original Nd-Fe-B magnet are 1.45 T,723 kA·m^(-1),and 419.8 kJ·m^(-3),respectively,and those of the sample with 4.0%Pr_(85)Cu_(15)alloy addition are 1.30 T,1271 kA·m^(-1),and 330.0 kJ·m^(-3),respectively.

关键词： Nd-Fe-B Low-melting alloy Hot-deformation Microstructure Coercivity mechanism

Characteristics of alumina particles in dispersion-strengthened copper alloys

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International Journal of Minerals,Metallurgy and Materials 2014年第11期21卷 1115-1119页

作者： Xue-hui Zhang xiao-xian Li School of Materials Science and Engineering Jiangxi University of Science and Technology School of Metallurgical and Chemical Engineering Jiangxi University of Science and Technology

Two types of alumina dispersion-strengthened copper（ADSC） alloys were fabricated by a novel in-situ reactive synthesis（IRS） and a traditional internal oxidation（IO） process. The features of alumina dispersoids in these ADSC alloys were investigated by X-ray diffraction, scanning electron microscopy, and high-resolution transmission electron microscopy. It is found that nano-sized γ-Al2O3 particles of approximately 10 nm in diameter are homogeneously distributed in the IRS-ADSC composites. Meanwhile, larger-sized, mixed crystal structure alumina with rod-shaped morphology is embedded in the IO-ADSC alloy. The IRS-ADSC composites can obtain better mechanical and physical properties than the IO-ADSC composites; the tensile strength of the IRS-ADSC alloy can reach 570 MPa at room temperature, its electrical conductivity is 85% IACS, and the Rockwell hardness can reach 86 HRB.

关键词： metallic matrix composites alumina copper in-situ reactive synthesis internal oxidation

Micro defects formation and dynamic response analysis of steel plate of quasi-cracking area subjected to explosive load

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Defence Technology（防务技术） 2024年第1期31卷 580-593页

作者： Zheng-qing Zhou Ze-chen du xiao Wang hui-ling Jiang Qiang Zhou Yu-long Zhang Yu-zhe Liu Pei-ze Zhang Research Institute of Macro-Safety Science University of Science and TechnologyBeijing100083China School of Civil and Resource Engineering University of Science and Technology BeijingBeijing100083China School of Mechanical Engineering Nantong UniversityNantong226019China China North Industry Advanced Technology Generalization Institute Beijing100089China China Academy of Ordnance Science China

As the protective component,steel plate had attracted extensive attention because of frequently threats of explosive *** this paper,the evolution of microstructure and the mechanism of damage in the quasi-cracking area of steel plate subjected to explosive load were discussed and the relationships between micro defects and dynamic mechanical response were *** the explosion experiment,five observation points were selected equidistant from the quasi-cracking area of the section of the steel plate along the thickness direction,and the characteristics of micro defects at the observation points were analyzed by optical microscope(OM),scanning electron microscope(SEM) and electron backscattered diffraction(EBSD).The observation result shows that many slip bands(SBs) appeared,and the grain orientation changed obviously in the steel plate,the two were the main damage types of micro *** addition,cracks,peeling pits,grooves and other lager micro defects were appeared in the lower area of the *** stress parameters of the observation points were obtained through an effective numerical *** mechanism of damage generation and crack propagation in the quasicracking area were clarified by comparing the specific impulse of each observation point with the corresponding micro *** result shows that the generation and expansion of micro defects are related to the stress area(*** upper compression area,the neutral plane area,and the lower tension area).The micro defects gather and expand at the grain boundary,and will become macroscopic damage under the continuous action of tensile ***,the micro defects at the midpoint of the section of the steel plate in the direction away from the explosion center(*** horizontal direction) were also *** was found that the specific impulse at these positions were much smaller than that in the thickness direction,the micro defects were only SBs and a few micro cracks,and the those decrea

关键词： Explosive load Quasi-cracking area Micro defects Steel plate Dynamic response Numerical simulation

Research progress in CALPHAD assisted metal additive manufacturing

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China Foundry 2024年第4期21卷 295-310页

作者： Ya-qing Hou xiao-qun Li Wei-dong Cai Qing Chen Wei-ce Gao du-peng He Xue-hui Chen Hang Su China Iron&Steel Research Institute Group Beijing 100081China Thermo-Calc Software AB SolnaSE-169Sweden KTH Royal Institute of Technology StockholmSE-100Sweden Central Iron and Steel Research Institute Beijing 100081China

Metal additive manufacturing(MAM)technology has experienced rapid development in recent *** both equipment and materials progress towards increased maturity and commercialization,material metallurgy technology based on high energy sources has become a key factor influencing the future development of *** calculation of phase diagrams(CALPHAD)is an essential method and tool for constructing multi-component phase diagrams by employing experimental phase diagrams and Gibbs free energy models of simple *** combining with the element mobility data and non-equilibrium phase transition model,it has been widely used in the analysis of traditional metal *** development of CALPHAD application technology for MAM is focused on the compositional design of printable materials,the reduction of metallurgical imperfections,and the control of microstructural *** endeavor carries considerable theoretical and practical *** paper summarizes the important achievements of CALPHAD in additive manufacturing(AM)technology in recent years,including material design,process parameter optimization,microstructure evolution simulation,and properties ***,the limitations of applying CALPHAD technology to MAM technology are discussed,along with prospective research directions.

关键词： metal additive manufacturing CALPHAD integrated computational material engineering powder bed fusion material design microstructure simulation

Generalized Stepping Stone Model with Ξ-resampling Mechanism

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Acta Mathematica Sinica,English Series 2022年第11期38卷 1998-2018页

作者： hui Li LIU xiao Wen ZHOU School of Mathematical Sciences Hebei Normal UniversityShijiazhuang 050024P.R.China Department of Mathematics and Statistics Concordia UniversityMontreal H3G1M8Canada

A generalized stepping stone model withΞ-resampling mechanism is a two dimensional probability-measure-valued stochastic process whose moment dual is similar to that of the classical stepping stone model except that Kingman’s coalescent is replaced byΞ-*** prove the existence of such a process by specifying its moments using the dual function-valuedΞ-coalescent process with geographical labels and migration,and then verifying a multidimensional Hausdorff moment *** also characterize the stationary distribution of the generalized stepping stone model and show that it is not reversible if the mutation operator is of uniform jump-type.

关键词： Generalized stepping stone model (Ξ,A,u1,u2-CPGM multidimensional Hausdorff moment problem stationary distribution reversibility

Structure of Friction-transferred Highly Oriented Poly(3-hexylthiophene) Thin Films

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Chinese Journal of Polymer Science 2016年第4期34卷 513-522页

作者： Li-guo Chai Hai-xin Zhou xiao-li Sun hui-hui Li 闫寿科 xiao-qiu Yang State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBeijing 100029China Basic Research Service MOSTBeijing 100862China

Oriented thin films of P3HT were obtained by a friction-transfer technique. The morphology and structure of the film were studied by means of optical microscopy, atomic force microscopy and transmission electron microscopy. Optical microscopy observation indicates that large size well-ordered P3HT thin films can be produced by a friction-transfer technique. Highly ordered lamellae were observed in P3HT friction-transferred films by electron microscopy. Electron diffraction results confirm the existence of high orientation with the a- and c-axes of P3HT crystals aligned in the film plane while the c-axis parallel to the friction-transfer direction. The atomic force microscopy observation of the as-prepared P3HT thin film shows, however, a featureless top surface morphology, indicating the structure inhomogeneity of the obtained film. To get highly oriented P3HT thin films with homogenous structure, high temperature annealing, solvent vapor annealing and self-seeding recrystallization of the friction-transferred film were performed. It is confirmed that solvent vapor annealing and self-seeding recrystallization methods are efficient in improving the surface morphology and structure of the friction- transferred P3HT thin film. Highly oriented P3HT films with unique structure can be obtained through friction-transfer with subsequent solvent vapor annealing and self-seeding recrystallization.

关键词： Poly(3-hexylthiophene) Friction-transfer Thin film Orientation.