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Preparation and Rheological Characterization of Long Chain Branching Polyglycolide

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Chinese Journal of Polymer Science 2024年第8期42卷 1177-1184页

作者： Wei-Lin Liu Ming-Fu Lyu Heng-Yuan zhang jian-Ye Liu Shi-Jun zhang beijing university of Chemical technology Beijing 100029China SINOPEC(beijing)Research Institute of Chemical Industry Co. Ltd.Beijing 100013China

The long chain branching(LCB)polyglycolide(PGA)was successfully prepared by the successive reactions of the terminal hydroxyl groups of PGA with triglycidyl isocyanurate(TGIC)and pyromellitic dianhydride(PMDA).The influence of LCB produced by functional group reaction on rheological and crystallization behavior was studied and discussed through linear rheology,uniaxial elongation and DSC(differential scanning calorimetry).The much higher viscosity and the more notable strain hardening behavior of modified PGA indicates the LCB with high degree of entanglements are *** melt strength of PGA is finally improved greatly and can make su re that the supercritical CO_(2)foaming can be carried out successfully.

关键词： Polyglycolide(PGA) Long chain branching(LCB) Rheology

High strength mullite-bond SiC porous ceramics fabricated by digital light processing

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Journal of Advanced Ceramics 2024年第1期13卷 53-62页

作者： jian Sun Jingde zhang Xu zhang Zihe Li jianzhang Li Sijie Wei Weibin zhang Weili Wang Guifang Han Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials(Ministry of Education) School of Materials Science and EngineeringShandong UniversityJinan 250061China Key Laboratory of Special Functional Aggregated Materials Ministry of EducationShandong UniversityJinan 250100China Materials and Structures Research Centre Department of Mechanical EngineeringUniversity of BathBath BA27AYUK National Engineering Research Centre of Ceramic Matrix Composite Manufacture technology Xi’an Golden Mountain Ceramic Composites Co.Ltd.Xi’an 710118China school of Physics and Materials Science Changji UniversityChangji 831100China

Fabricating SiC ceramics via the digital light processing(DLP)technology is of great challenge due to strong light absorption and high refractive index of deep-colored SiC powders,which highly differ from those of resin,and thus significantly affect the curing performance of the photosensitive SiC *** this paper,a thin silicon oxide(SiO_(2))layer was in-situ formed on the surface of SiC powders by pre-oxidation *** method was proven to effectively improve the curing ability of SiC *** SiC photosensitive slurry was fabricated with solid content of 55 vol%and viscosity of 7.77 Pa·s(shear rate of 3. s^(−1)).The curing thickness was 50μm with exposure time of only 5 ***,a well-designed sintering additive was added to completely convert low-strength SiO_(2) into mullite reinforcement during *** mullite-bond SiC ceramics were successfully *** flexural strength of SiC ceramics sintered at 1550℃in air reached 97.6 MPa with porosity of 3..2 vol%,as high as those prepared by spark plasma sintering(SPS)techniques.

关键词： digital light processing(DLP) SiC ceramics pre-oxidation mullite-bond SiC mechanical properties

Analysis of mechanical strengths of extreme line casing joint considering geometric, material, and contact nonlinearities

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Petroleum Science 2024年第3期21卷 1992-2004页

作者： Ji-Yun zhang Chi Peng jian-Hong Fu Quan Cao Yu Su jian-Yun Pang Zi-Qiang Yu Petroleum Engineering school Southwest Petroleum UniversityChengdu610500SichuanChina Engineering technology Research Institute of CNPC Southwest Oil and Gas Field Company Chengdu610017SichuanChina

To address the challenges associated with difficult casing running,limited annular space,and poor cementing quality in the completion of ultra-deep wells,the extreme line casing offers an effective solution over conventional ***,due to its smaller size,the joint strength of extreme line casing is reduced,which may cause failure when running in the *** address this issue,this study focuses on the CST-ZTΦ13..7 mm×7.72 mm extreme line casing and employs the elastic-plastic mechanics to establish a comprehensive analysis of the casing joint,taking into account the influence of geometric and material nonlinearities.A finite element model is developed to analyze the forces and deformations of the extreme line casing joint under axial tension and external collapse *** model investigates the stress distribution of each thread tooth subjected to various tensile forces and external ***,the tensile strength and crushing strength of the extreme line casing joint are determined through both analytical and experimental *** findings reveal that,under axial tensile load,the bearing surface of each thread tooth experiences uneven stress,with relatively high equivalent stress at the root of each thread *** end thread teeth are valuable spots for *** is observed that the critical fracture axial load of thread decreases linearly with the increase of thread tooth *** external pressure,the circumferential stress is highest at the small end of the external thread,leading to yield *** tensile strength of the joint obtained from the finite element model exhibits a relative error of less than 7%compared to the analytical and experimental values,proving the reliability of the finite element *** tensile strength of the joint is 3.91.9 k ***,in terms of anti-collapse capability,the joints demonstrate higher resistance to collapse compared to the casing body,which is consistent with the test resul

关键词： Extreme line casing Elastic-plastic mechanics Finite element analysis Tensile strength Collapse strength

Carbon coated LaFe_(0.92)Pd_(0.08)O_(3. composites for catalytic transfer hydrogenation:Balance in the ability of substrates adsorption and conversion

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Nano Research 2024年第5期17卷 3724-3732页

作者： Bowen Wang Nan zhang Ping Xiao jian zhang Sónia A.C.Carabineiro Junjiang Zhu Hubei Key Laboratory of Biomass Fibers and Eco-dyeing&Finishing College of Chemistry and Chemical EngineeringWuhan Textile UniversityWuhan 430200China College of Chemistry and Materials Engineering Wenzhou UniversityWenzhou 325035China LAQV-REQUIMTE Department of ChemistryNOVA School of Science and TechnologyUniversidade NOVA de LisboaLargo da Torre2829-516 CaparicaPortugal

Catalytic transfer hydrogenation(CTH)is a green and efficient pathway for selective hydrogenation of unsaturated aldehydes and ***,managing the abilities of solid catalysts to adsorb substrates and to convert them into desired products is a challenging ***,we report the synthesis of carbon coated LaFe_(0.92)Pd_(0.08)O_(3. composites(LFPO-8@C)for CTH of benzaldehyde(BzH)into benzyl alcohol(BzOH),using isopropanol(IPA)as hydrogen *** coating with carbon improves the ability to adsorb/transfer reactants from solution to active sites,and the doping of Pd2+at Fe3.site strengthens the ability of LaFeO_(3. to convert BzH into BzOH.A balanced point between them(i.e.,abilities to adsorb BzH and to convert BzH into BzOH)is obtained at LFPO-8@C,which exhibits a BzOH formation rate of 3.88 mmol·gcat^(-1)·h^(-1) at 180℃ for 3.h,which is 1.50 and 2.72 times faster than those of LFPO-8 and LaFeO_(3.@C.A reaction mechanism is proposed,in which the acidic sites(e.g.,Fe^(4+),oxygen vacancy)are used for the activation of C=O bond of BzH and O-H bond of IPA,and the basic sites(e.g.,lattice oxygen)for the activation ofα-H(O-H)bond of IPA.

关键词： LaFe_(0.92)Pd_(0.08)O_(3. porous carbon catalytic transfer hydrogenation isopropanol reaction mechanism

A-site assisted perovskite crystallization via ion-exchange MOFs for high efficient and stable perovskite solar cells

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Journal of Energy Chemistry 2024年第6期93卷 436-442,I0011页

作者： Xingrui zhang jian zhang Wei Wang Boyuan Hu Yayu Dong Debin Xia Kaifeng Lin Yulin Yang MIIT Key Laboratory of Critical Materials technology for New Energy Conversion and Storage School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001HeilongjiangChina

Here,a novel strategy is proposed targeting the volatility of A-site cations and the disordered arrangement of perovskite grains through employing Cs~+contained metal-organic frameworks In-aip(Cs)obtained by ion-exchange and crystalline *** forces between Cs-O atoms split the pore channels of the pristine In-aip,endowing In-aip(Cs)with multidimensional charge transport channels,In addition,the partially freed Cs~+in the interlayer compensates for the vacancy of A-site cations during the perovskite preparation *** In-aip(Cs)modified perovskite films have a flat morphology,large grains and excellent optoelectronic *** from the high-quality perovskite films and faster charge extraction,the In-aip(Cs)-modified PSCs achieved a champion PCE of 23.03.,superior to the In-aip-modified(22.29%)and control device(21.13.),More importantly,the unencapsulated PSCs modified with In-aip(Cs)exhibited outstanding humidity and thermal *** a period of almost 1000 h,the unencapsulated In-aip(Cs)-modified device retained 85%of its initial PCE after storing in a glove box at 85℃,and retained 87%of the primary PCE upon storage in ambient condition at 25℃under a humidity of 40%.

关键词： Metal-organic frameworks PSCs Stability Defect passivation

Simulation of Thermodynamics and Kinetics for KR Desulphurization

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Journal of Iron and Steel Research International 2011年第S2期18卷 98-106页

作者： XU An-jun1, zhang Mao-lin2, zhang Hui-ning1, LI An-dong3.(1. school of Metallurgical and Ecological Engineering, {3. of Science and technology beijing, beijing 100083.china 2. Steel-Making and Continuous Casting Engineering Institute, Capital Engineering and Research Incorporation Limited, beijing 100176,china 3. Stainless Steel Company, Baosteel Group, Shanghai 201900,china) Univ Sci & Technol beijing Sch Met & Ecol Engn Beijing 100083 Peoples R China Capital Engn & Res Inc Ltd Steel Making & Continuous Casting Engn Inst Beijing 100176 Peoples R China Stainless Steel Co Baosteel Grp Shanghai 201900 Peoples R China

This paper seeks to optimize parameters, reduce the cost of desulphurization and the consumption of operation about KR pretreatment of hot metal at the Stainless Steel Company, Baosteel Group. Based on the theoretical analysis of physical chemistry in metallurgy, simulation experiments of the KR desulphurization of hot metal were conducted in a laboratory and the composition of the desulphurization was optimized, by means of chemical analysis, DSC, SEM and EDS. The water modeling displays the fluid flow characteristics of KR desulphurization. Combination of the techniques and production at the Stainless Steel Company, Baosteel Group, the optimized parameters of the process are put forward.

关键词： desulphurization of hot metal KR, desulphurization thermodynamics water model

Large deflection deformation behavior of a Zr-based bulk metallic glass for compliant spinal fixation application

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Journal of Materials Science & technology 2024年第6期173卷 86-99页

作者： Diao-Feng Li Chun-Guang Bai Zhi-Qiang zhang Hui-Bo zhang Nan Li jian Zhao Shi-Changxu Innovation Center for Advanced Materials Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China

A novel compliant spinal fixation designed based on the concept of compliant mechanisms can reduce the stress-shielding effect and adjacent segment degeneration(ASD)effectively,but propose higher requirements for the properties of the used *** metallic glasses(BMGs),as a kind of young biomaterials,exhibiting excellent comprehensive properties,which are attractive for compliant spinal ***,according to the practical service condition of the basic elements in compliant spinal fixation,large deflection deformation behaviors of Zr_(61)Ti_(2)Cu_(25)Al_(12)(at.%,ZT1)BMG beam,including elastic,yielding and plastic were investigated *** was shown that the theoretical nonlinear analytical solution curve as the benchmark not only with the capacity to predict the nonlinear load-deflection relation within the elastic deformation regime,but also assists to capture the yielding event roughly,which can be used as a powerful design tool for *** capture the beginning of the yielding event exactly,bending proof strength(σ_(p),0.05%)accompanied with tiny permanent strain of 0.05% was proposed and determined for BMGs in biomedical implant applications,which is of significance for setting the allowable operating limits of the basic flexible *** approach of interrupted loading-unloading cycles,plastic deformation driven by the bending moment can be classified into two typical stages:the initial stage which mainly characterized by the nucleation and intense interaction of abundant shear bands when the plastic strain below the critical value,and the second stage which dominated by the progressive propagation of shear bands and coupled with the emergence of shear offsets on tensile *** plasticity of BMG beam structures depends on the BMG's inherent plastic zone size(rp).When the half beam thickness less than that of the rp,the plastic deformation of BMGs will behave in a stable manner,which can be acted as the margin of safety effectiv

关键词： Metallic glasses Biomaterials Compliant spinal fixation Large deflection deformation Plastic deformation

Ash removal from inferior coal via ammonium fluoride roasting and simultaneous yield of white carbon black

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International Journal of Mining Science and technology 2024年第2期34卷 261-279页

作者： Xuqin Duan Shuaiyu Lu Yuxiao Fu Jiazhe zhang Tong Liu jian Ma school of Civil and Resource Engineering University of Science&Technology BeijingBeijing 100083China State Key Laboratory for Efficient Mining of Metal Mines University of Science&Technology BeijingBeijing 100083China china Coal Processing and Utilizaiton Association Beijing 100013China

The quality upgrading and deashing of inferior coal by chemical method still faces great *** dangers of strong acid,strong alkali,waste water and exhaust gas as well as high cost limit its industrial *** paper systematically investigates the ash reduction and desilicification of two typical inferior coal utilizing ammonium fluoride roasting *** the optimal conditions,for fat coal and gas coal,the deashing rates are 69.02%and 54.13.,and the desilicification rates are 92.64%and 90.27%,*** molar dosage of ammonium fluoride remains consistent for both coals;however,the gas coal,characterized by a lower ash and silica content(less than half that of the fat coal),achieves optimum deashing effect at a reduced time and *** majority of silicon in coal transforms into gaseous ammonium fluorosilicate,subsequently preparing nanoscale amorphous silica with a purity of 99.90%through ammonia *** of the fluorine in deashed coal are assigned in inorganic minerals,suggesting the possibility of further fluorine and ash removal via *** research provides a green and facile route to deash inferior coal and produce nano-scale white carbon black simultaneously.

关键词： Inferior coal Deashing treatment Silicon recycling Ammonium fluoride roasting White carbon black

Permanent lining castable with low bulk density and thermal conductivity:bauxite castable for tundish obtained by adding pearlescent sand

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Journal of Iron and Steel Research International 2024年第3期31卷 634-646页

作者： Yi Wang jian Yang Bao Wang Hai-jun zhang Juan Han Pei-yan Pei Wen-long Lv jian-an Zhou The State Key Laboratory of Refractories and metallurgy Wuhan University of Science and TechnologyWuhan 430081HubeiChina Key Laboratory for Ferrous metallurgy and Resources Utilization of Ministry of Education Wuhan University of Science and TechnologyWuhan 430081HubeiChina Wuhan Research Institute of Metallurgical Construction MCCWuhan 430081HubeiChina

The low thermal conductivity and light mass of castables for tundish permanent linings are crucial for minimizing the heat loss of molten *** consideration of the low bulk density and thermal conductivity of pearlescent sand,the thermal insulation performance of castables was attempted to be improved by adding pearlescent *** sand was modified to prevent the strength of its porous structure from *** modification mechanism of pearlescent sand and the effect of pearlescent sand on the performance of bauxite castables were *** results suggested that the addition of the modified pearlescent sand significantly raised the apparent porosity and decreased the bulk density of bauxite *** 1000℃,the bulk density of more than 60%of the modified pearlescent sand-bauxite castable was only 2.03.g/cm^(3..The mechanical properties and thermal shock resistance of the modified pearlescent sand-bauxite castable were inferior to those of conventional bauxite castable but were adequate to meet the use conditions of casta-bles for tundish permanent *** high temperatures of 200-800℃,the thermal conductivity of more than 60%of the modified pearlescent sand-bauxite castable was smaller than that of conventional bauxite *** addition of the modified pearlescent sand can greatly reduce the thermal conductivity and bulk density of bauxite castable.

关键词： Pearlescent sand-Hydrophobic modification Bauxite castable Thermal insulation performance Mechanical property