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Modulating the Oxidation Degree of Linear Polyethyleneimine for Preparation of Highly Efficient and Low-cytotoxicity Degradable Gene Delivery Carriers

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Chinese Journal of Polymer Science 2024年第11期42卷 1699-1709,I0008页

作者： Xiao-Ya Guo Zhi-Yu Yang hua-Pan Fang Dan-hua zhou Xuan Pang hua-Yu Tian Xue-Si Chen Changchun Institute of Applied Chemistry Chinese Academy of SciencesChangchun130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefei230026China State Key Laboratory of Physical Chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamen361005China Innovation Laboratory for Sciences and Technologies of Energy Materials of Fujian Province(IKKEM) Xiamen361005China

Polyethyleneimine(PEI),as a widely used polymer material in the field of gene delivery,has been extensively studied for modification and shielding to reduce its ***,research aimed at preparing degradable PEI is *** this work,the hydrogen peroxide(H_(2)O_(2))oxidation method was used to introduce degradable amide groups in the PEI and a series of oxidized PEI22k(oxPEI22k)with different degrees of oxidation were synthesized by regulating the dosage of H_(2)O_(2).The relationship between the oxidation degree of oxPEI22k and the gene transfection efficiency of oxPEI22k was studied in detail,confirming that the oxPEI22k with oxidation degrees of 16.7%and 28.6%achieved improved transfection efficiency compared to unmodified *** oxPEI22k also proved reduced cytotoxicity and improved ***,this strategy was extended to the synthesis of low-molecular-weight *** oxPEI1.8k with suitable oxidation degree also achieved improved transfection efficiency and reduced *** brief,this work provided high-efficiency and low-cytotoxicity degradable gene delivery carriers by regulating the oxidation degree of PEI,which was of great significance for promoting clinical applications of PEI.

关键词： Polyethyleneimine Gene delivery Gene transfection Degradable gene carriers

Particle Residence Time in Column Flotation Based on Cyclonic Separation

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Journal of China University of Mining and Technology 2007年第3期17卷 349-353页

作者： zhou Xiao-hua LIU Jiong-tian Department of Mining Engineering University of Kentucky Lexington KY40506 USA School of Chemical Engineering and Technology China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

The cyclonic static micro-bubble column flotation (FCSMC) is an effective separation device for fine particle treatment. The high mineralization rate and short flotation time of this equipment can be attributed to its unique cyclonic force field. It also has been observed that the presence of a cyclonic force field leads to a lower bottom separation size limit and a reduction of unselective entrainment. The collection zone of the column is considered to consist of two parts,a column separation zone and a cyclonic zone. Total recovery of the collection zone was developed. For our study,we analyzed the particle movement in the cyclonic zone. Particle residence time equations for the cyclonic zone were de-rived by force analysis. Results obtained in this study provide a theoretical foundation for the design and scale-up of the FCSMC.

关键词： column flotation cyclonic separation residence time

Electroslag Remelting Withdrawing Technology for Offshore Jack-up Platform Rack Steel Manufacturing Process

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Journal of Iron and Steel Research International 2016年第4期23卷 297-304页

作者： Xi-min ZANG Tian-yu QIU Wan-ming LI Xin DENG zhou-hua JIANG hua SONG School of Material and Metallurgy University of Science and Technology Liaoning School of Metallurgy Northeastern University School of Mechanical Engineering and Automation University of Science and Technology Liaoning

Offshore jack up platform rack steel must exhibit high strength and toughness as well as excellent welding properties. A high-quality large ingot is a prerequisite for obtaining a high-performance rough part. The electroslag remelting withdrawing （ESRW） technology using a T-shaped mold and bifilar mode was introduced to replace casting technology. Numerical simulation of the ESRW process was performed to determine the distribution of the temperature and velocity fields and to determine the optimum process for producing rack steels. Several A514Q slab ingots with dimensions of 0.32 m×1.40 m × 4.00 m were produced using ESRW technology in an industrial plant. The industrial test indicated that slab ingots produced by the ESRW method exhibited uniform chemical compositions and compact macrostructures. A 115.4 mm thick plate was produced from the rough ingot after 11 roiling passes. Samples were obtained from different positions in the steel plate to test the mechanical performance and examine the microstructure, and the results revealed that the properties of the steel plate satisfied ASTM standards. The ESRW process improved the tensile strength and toughness of the slab ingot, enabling significant improvements in the anisotropy and low temperature toughness, which are critical for the development of rack steel for offshore platforms.

关键词： electroslag remelting withdrawing rack steel mechanical performance low temperature toughness

Metallurgical Source of Cryogenic Intergranular Fracture of Fe-38Mn Austenitic Alloy

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Journal of Iron and Steel Research International 2000年第1期7卷 31-35页

作者： FU Rui-dong ZHENG Yang-zeng LI Shao-hua zhou Hui-hua Yanshan University Central Iron & Steel Research Institute Tsinghua University

SEM and Field emitting TEM-EDAX were used to investigate the fracture surface of series impact specimens and the grain boundary chemistries of VIM(vacuum-inductionmelted) Fe-38 Mn austenitic alloy before and after ESR(electroslag remelting,).The quantity and the size of inclusions were also *** results show that the VIM Fe-38 Mn austenitinic alloy water-quenched from 1 100 C undergoes an obvious ductile-to-brittle transition,and the impact work at ambient temperature is 242 J,the corresponding fracture surface exhibits a dimple ***,the impact work at 77 K of VIM alloy is only 25 J and the fracture mode is IGF(intergranular fracture).After ESR,the impact work at ambient temperature is 320 J and the fracture surface exhibits a character of "volcano lava"(meaning excellent toughness);The impact work at 77 K is up to 300 J and the fracture mode is micro void coalescence mixed with *** segregation of Mn is not found in all specimens,but the segregation of S is observed,and the S segregation is decreased after *** examined results of inclusions show that ESR reduces the quantity and improves the morphology of *** the above results it can be seen that the cryogenic IGF of VIM Fe-38 Mn austenitic alloy is related to the S segregation at grain *** ESR the decrease in the quantity and size of inclusion results in the increase of the impact work at ambient temperature,while the restriction of IGF is related to the decrease in the total level,and hence in the grain boundary segregation of S.

关键词： rich Mn austenitic alloy cryogenic intergranular fracture grain boundary segregation electroslag remelting

Effects of Temperature and Strain Rate on Flow Behavior and Microstructural Evolution of Super Duplex Stainless Steel under Hot Deformation

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Journal of Iron and Steel Research International 2016年第3期23卷 244-252页

作者： Ming MA hua DING Zheng-you TANG Jing-wei ZHAO zhou-hua JIANG Guang-wei FAN School of Material Science and Engineering Northeastern University School of Mechanical Materials and Mechatronic EngineeringUniversity of Wollongong Technology Center Shanxi Taigang Stainless Steel Co.Ltd.

Hot compression tests were carried out in the temperature range of 1 223-1 473 Kand strain rate range of0.01-30s^-1 to investigate the flow behavior and microstructural evolution of super duplex stainless steel 2507（SDSS2507）.It is found that most of the flow curves exhibit a characteristic of dynamic recrystallization（DRX）and the flow stress increases with the decrease of temperature and the increase of strain *** apparent activation energy Qof SDSS2507 with varying true strain and strain rate is *** the strain increases,the value of Qdeclines in different ways with varying strain *** microstructural evolution characteristics and the strain partition between the two constituent phases are significantly affected by the Zener-Hollomon parameter（Z）.At a lower lnZ,dynamic recovery（DRV）and continuous dynamic recrystallization（CDRX）of the ferrite dominate the softening mechanism during the *** this time,steady state deformation takes place at the last stage of *** contrast,a higher lnZ will facilitate the plastic deformation of the austenite and then activate the discontinuous dynamic recrystallization（DDRX）of the austenite,which leads to a continuous decline of the flow stress even at the last deformation stage together with CDRX of the ferrite.

关键词： duplex stainless steel hot deformation behavior dynamic recovery dynamic recrystallization strain partition

Effect of melt current on multi-physical field and heat flow distribution during ESR process based on model of dynamic formation of slag skin

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Journal of Iron and Steel Research International 2023年第6期30卷 1258-1267页

作者： Fu-bin Liu Xin-hao Yu hua-bing Li zhou-hua Jiang Hong-chun Zhu Xin Geng School of Metallurgy Northeastern UniversityShenyang 110819LiaoningChina

A numerical model coupled with a multi-physical field based on dynamic formation of slag skin is *** validation by comparing the experimental and simulation results of depth of metal pool,slag skin thickness and melt rate,it is utilized to investigate the effect of melt current on the coupled multi-physical field,slag skin thickness,metal pool depth and the heat flow distribution during electroslag remelting(ESR)Inconel 625 solidification *** results showed that with the increase in the melt current,the velocities of ESR system and the temperature of metal pool increased,whereas the highest temperature of slag bath firstly decreased and then *** the increase in the melt current,the slag skin thickness,metal pool depth and melt rate ***,the characteristics of the heat flow distribution and the effect of melt current on the heat flow distribution were analysed.

关键词： Electroslag remelting Melt current Slag skin Model Multi-physical field

Corrosion behavior of ferritic stainless steel with 15wt% chromium for the automobile exhaust system

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International Journal of Minerals,Metallurgy and Materials 2013年第9期20卷 850-860页

作者： hua-bing Li zhou-hua Jiang Hao Feng Hong-chun Zhu Bin-han Sun Zhen Li School of Materials and Metallurgy Northeastern University

The effect of chloride ion concentration, pH value, and grain size on the pitting corrosion resistance of a new ferritic stainless steel with 15wt% Cr was investigated using the anodic polarization method. The semiconducting properties of passive films with different chloride ion concentrations were performed using capacitance measurement and Mott-Schottky analysis methods. The aging precipitation and intergranular corrosion behavior were evaluated at 400- 900℃. It is found that the pitting potential decreases when the grain size increases. With the increase in chloride ion concentration, the doping density and the flat-bland potential increase but the thickness of the space charge layer decreases. The pitting corrosion resistance increases rapidly with the decrease in pH value. Precipitants is identified as Nb（C,N） and NbC, rather than Cr-carbide. The intergranular corrosion is attributed to the synergistic effects of Nb（C,N） and NbC precipitates and Cr segregation adjacent to the precipitates.

关键词： ferritic stainless steel corrosion resistance pitting chlorides intergranular corrosion grain size

Stereoselective cycloaddition of N-acyliminium cations withα,β-unsaturated ketones and esters

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Chinese Chemical Letters 2009年第7期20卷 805-808页

作者： Ling Feng Qian Yue hua zhou Wei Zhang State Key Laboratory of Applied Organic Chemistry Lanzhou University Lanzhou 730000 China

The cycloaddition of N-acyliminium cations with some deactivated alkenes such as α,β-unsaturate ketones and esters has been investigated. In most cases, the N-acyliminium cations produced from 3-hydroxy-2-arylisoindol-1-ones in the presence of ***2 could be reacted with α,β-unsaturated ketones and esters to afford stereoselectively the cycloaddition products 6-acylisoindolo[2,1- a]quinolin-11-ones in moderate to high yields. C 2009 Wei Zhang. Published by Elsevier B.V, on behalf of Chinese Chemical Society. All rights reserved.

关键词： Cycloaddition N-acyliminium cation 3-Hydroxy-2-arylisoindol- 1-one α,β-Unsaturated ketones 6-Acylisoindolo[2,1-a]quinolin- 11- ones

Novel Gas-liquid Hybrid Discharge Reactor for 4-CP Containing Wastewater Treatment

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Chinese Chemical Letters 2006年第4期17卷 541-544页

作者： Yi ZHANG Ming hua zhou Le Cheng LEI Institute of Environmental Engineering Zhejiang University Hangzhou 310027

In order to improve 4-CP degradation efficiency, a novel gas-liquid hybrid discharge （liD） reactor was developed. Removal of 4-CP with spark-spark discharge （SSD） was higher than that with spark-corona discharge （SCD）. Amount of H2O2 and O3 produced with SSD were larger than that with SCD. OH formation was increased by the combination of H2O2 and O3. The contribution of ·OH （38 % formed by O3 conversion） oxidation on removal of 4-CP accounted for nearly 60 %. The other effects of ultraviolet radiation, intense shock waves and pyrolysis, played partial roles in about 40 % of removal rate.

关键词： Gas-liquid hybrid spark-spark discharge O3 H2O2, ·OH.