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Effect of specimen gauge reduction on uniaxial tension properties of reinforcing steel

Journal of Iron and Steel Research International 2020年第8期27卷 964-971页

作者： A.Triwiyono A.l.Han A.Aryanto S.Tudjono B.S.Gan Civil Engineering Department Gadjah Mada UniversitySleman 55283YogyakartaIndonesia Civil Engineering Department Diponegoro UniversityTembalang 50275SemarangIndonesia Civil Engineering Department Bandung Institute of TechnologyCoblong 40132BandungIndonesia Department of Architecture College of EngineeringNihon UniversityKoriyama 963-8642Fukushima PrefectureJapan

The Standard Test Methods for Tension Testing of Metallic Materials (ASTM E8) mandates a specimen gauge reduction for obtaining the tensile properties of reinforcing steel bars. The standard outlines the specimen preparation requirements and methods to ensure that test results well represent the material properties. On the other hand, some codes differ regarding the approach to specimen preparation. They do not apply gauging, for both deformed and plain steel bars. Thus, the effect of specimen gauge reduction on the tensile properties of reinforcing steel bars was evaluated, and the interconnection of properties to the layer hardness was analysed. The experiment governed a range of deformed hot-rolled bar sizes, tested in tension using precision instruments. The Rockwell hardness test was implemented layerwise on the specimen’s cross section, and the hardness number (HRC) was measured as a function of the layer distance to the centre. A finite element model was constructed to study the stress concentrations induced by a constant indentation, simulating the HRCs, and to numerically construct the stress–strain relationship of ungauged steel bars based on the core properties and the section HRC relationship. Scanning electron microscopy readings were performed to visually and chemically justify the results. It was shown that the specimen gauge reduction significantly influenced the resulting stress–strain behaviour of the material, and the yield and ultimate strengths were reduced. It was also demonstrated that the hardness response is proportional to the distance to the specimen’s axes. The corresponding yield and ultimate strengths thus increased accordingly, from the inner to the outer layers of the bar. Testing a gauged specimen will therefore result in lower strength than that of an ungauged steel bar.

关键词： Tensile property Specimen gauge reduction Rockwell hardness number Finite element model Reinforcing steel

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Synchronous Synthesis and Immobilization of Metal Phthalocyanine for Aerobic Oxidation of Styrene

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China Petroleum Processing & Petrochemical Technology 2020年第4期22卷 73-84页

作者： liu Yefeng lüYing li Zeyu Shen Yue Wang Ruixin School of Chemical Engineering and Technology North University of ChinaTaiyuan 030051

In this study,the precursor 4-(4-carboxy-phenoxy)phthalonitrile(CPPN)was first bonded onto the silica gel surface modified with poly(glycidyl methacrylate)(PGMA)(PGMA/SiO2)to prepare CPPN-PGMA/SiO2,and metal phthalocyanine(MPc;M=Co,Fe,Cu,Mn)was supported on the PGMA/SiO2 surface to prepare MPc-PGMA/SiO2 by synchronous synthesis and immobilization with phthalonitrile and metal salt in the *** chemical composition and surface morphology were characterized by the Fourier transform infrared(FTIR)spectroscopy,UV-Vis spectroscopy,scanning electron microscopy(SEM),X-ray photoelectron spectroscopy(XPS),and thermogravimetry analysis(TGA).The catalytic performance of MPc-PGMA/SiO2 in epoxidation of styrene was also investigated with molecular oxygen acting as the *** results show that MPc-PGMA/SiO2 can efficiently and selectively catalyze molecular oxygen for oxidation of styrene to styrene oxide under mild ***,the catalytic activity differs substantially depending on the central metal,and a highest catalytic activity is achieved by CoPc-PGMA/*** CoPc-PGMA/SiO2 amount and temperature can also affect the catalytic oxidation of styrene,and at normal atmospheric pressure,a maximum conversion rate of styrene(99%)and selectivity of styrene oxide(53%)are obtained using 0.1 g of CoPc-PGMA/SiO2(22.61μmol of CoPc)at 100℃ for 6 ***-PGMA/SiO2 also has excellent reusability,and the conversion rate of styrene is still over 90%after 5 cycles.

关键词： metal phthalocyanine poly glycidyl methacrylate synchronous synthesis and immobilization catalytic oxidation styrene

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Aortic valve replacement reduces mortality in moderate aortic stenosis:a systematic review and meta-analysis

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Journal of Geriatric Cardiology 2023年第1期20卷 61-67页

作者： Kyle B Franke Dimple Bhatia Ross l Roberts-Thomson Peter J Psaltis Adelaide Medical School The University of AdelaideAdelaideAustralia Vascular Research Centre Lifelong Health ThemeSouth Australian Health and Medical Research InstituteAdelaideAustralia Department of Cardiology Royal Adelaide HospitalAdelaideAustralia

BACKGROUND With the introduction of transcatheter aortic valve replacement and an evolving understanding of the natural progression and history of aortic stenosis,the potential for earlier intervention in appropriate patients is promising;however,the benefit of aortic valve replacement in moderate aortic stenosis remains *** Pubmed,Embase,and the Cochrane library databases were searched up until 30th of December 2021 using keywords including moderate aortic stenosis and aortic valve *** reporting all-cause mortality and outcomes in early aortic valve replacement(AVR)compared to conservative management in patients with moderate aortic stenosis were *** ratios were generated using random-effects meta-analysis to determine effect *** 3470 publications were screened with title and abstract review,which left 169 articles for full-text *** these studies,7 met inclusion criteria and were included,totalling 4,827 *** studies treated AVR as a time-dependent co-variable in cox-regression multivariate analysis of all-cause *** with surgical or transcatheter AVR was associated with a 45% decreased risk of all-cause mortality(HR=0.55[0.42-0.68],I2=51.5%,Pll studies were representative of the overall cohort with appropriate sample sizes,with no evidence of publication,detection,or information biases in any of the *** In this systematic review and meta-analysis,we report a 45% reduction in all-cause mortality in patients with moderate aortic stenosis who were treated with early aortic valve replacement compared to a strategy of conservative *** control trials are awaited to determine the utility of AVR in moderate aortic stenosis.

关键词： aortic stenosis analysis

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Electrochemical performance of la_(2)NiO_(4+δ)-Ce_(0.55)la_(0.45)O_(2−δ)as a promising bifunctional oxygen electrode for reversible solid oxide cells

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Journal of Advanced Ceramics 2021年第2期10卷 328-337页

作者： Pengzhang li Wei Yang Chuanjin Tian Wenyan Zhao Zhe lü Zhipeng Xie Chang-An Wang School of Materials Science and Engineering Jingdezhen Ceramic InstituteJingdezhen333403China School of Physics Harbin Institute of TechnologyHarbin150001China State Key laboratory of New Ceramics and Fine Processing School of Materials Science and EngineeringTsinghua UniversityBeijing100084China

In this work,la_(2)NiO_(4+δ)-Ce_(0.55)la_(0.45)O_(2−δ)(denoted as lNO-xlDC)with various lDC contents(x=0,10,20,30,and 40 wt%)were prepared and evaluated as bifunctional oxygen electrodes for reversible solid oxide cells(RSOCs).Compared with the pure lNO,the optimum composition of lNO-30lDC exhibited the lowest polarization resistance(Rp)of 0.53 and 0.12Ω·cm^(2)in air at 650 and 750℃,*** enhanced electrochemical performance of lNO-30lDC oxygen electrode was mainly attributed to the extended triple phase boundary and more oxygen ionic transfer *** hydrogen electrode supported single cell with lNO-30lDC oxygen electrode displayed peak power densities of 276,401,and 521 mW·cm^(−2)at 700,750,and 800℃,***,the electrolysis current density of the single cell demonstrated 526.39 mA·cm^(−2) under 1.5 V at 800℃,and the corresponding hydrogen production rate was 220.03 ml·cm^(−2)·h^(−1).The encouraging results indicated that lNO-30lDC was a promising bifunctional oxygen electrode material for RSOCs.

关键词： la_(2)NiO_(4+δ)(lNO) oxygen electrode electrochemical performance reversible solid oxide cells(RSOCs)

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A cceleration of Ionospheric Out-Flowing Ions in the Substorm in Geo-magnetotail

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Chinese Physics letters 1999年第12期16卷 908-910页

作者： SHI Jian-kui lIU Zhen-Xing T.l.Zhang K.Torkar Center for Space Science&Applied Research Chinese Academy of SciencesBeijing 100080 Space Research Institute Austrian Academy of SciencesA-8010 GrazAustria

Using dynamics equation, acceleration of out-flowing ion during dipolarization in a substorm in the magneto-tail is simulated. The main results show that: (1) The ion distribution function that is initially exponentially decreasing with increasing speed is turned into a single peak distribution, and with time the peak moves towards higher speed. (2) The peak moves along V⊥ faster than that along V||, and the ion acceleration mainly occurs in the middle of the dipolarization. (3) The higher the initial energy, the faster the peak moves, and the more energy is obtained by the ions. The ion energy theoretically calculated is as high as about 102 keV, this is consistent with the observation.

关键词： storm faster acceleration

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Template synthesis of silver indium sulfide based nanocrystals performed through cation exchange in organic and aqueous media

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Nano Research 2021年第7期14卷 2321-2329页

作者： Na Gao Rubo Zhang Bingkun Chen Jinfeng Zhang Xiaoling Zhang Andrey l.Rogach School of Chemistry and Chemical Engineering Beijing Institute of TechnologyBeijing 100081China School of Optics and Photonics Beijing Institute of TechnologyBeijing 100081China School of life Science Beijing Institute of TechnologyBeijing 100081China Department of Materials Science and Engineering and Centre for Functional Photonics(CFP)City University of Hong KongHong Kong SARChina

Heavy-metal-free silver based I-III-VI semiconductor nanocrystals(NCs),including ternary silver indium sulfide(AgInS_(2))and derivative quaternary silver indium zinc sulfide(i.e.,AgInZn_(2)S_(4))NCs,possess advantages of low toxicity,and size-tunable band gaps approaching near-infrared spectral range,which make them candidates for use in optoelectronic and biological ***,we report syntheses of AgInS_(2) based NCs starting from In_(2)S_(3) template,which have been performed both in organic and aqueous phase through cation *** a result,ternary silver indium sulfide and quaternary silver indium zinc sulfide NCs are obtained in both organic and aqueous media,and confirmed to be orthorhombic AgInS_(2) NCs and hexagonal AgInZn_(2)S_(4) NCs,***,the aqueous AgInZn_(2)S_(4) NCs with red emission and low cytotoxicity are explored for the cancer cell imaging.

关键词： template synthesis silver indium sulfide based nanocrystals cation exchange organic and aqueous media

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Experimental investigation and theoretical modeling on scale behaviors of high salinity wastewater in zero liquid discharge process of coal chemical industry

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Chinese Journal of Chemical Engineering 2020年第4期28卷 969-979页

作者： Kai lu Yang lü Youxiang Bai Jueru Zhang Nanxi Bie Yongsheng Ren Yulong Ma State Key laboratory of High-efficiency Coal Utilization and Green Chemical Engineering Department of Chemistry&Chemical EngineeringNational Demonstration Center for Experimental Chemistry EducationNingxia UniversityYinchuan 750021China

Zero liquid discharge(ZlD)treatment and reuse equipment of high salinity wastewater in coal-chemical industry often occur in various types of blockage problems because of high salt content,affecting the long-term stability of the *** this study,the effects of solution temperature,steel,reaction time and wall roughness on fouling were *** changes in the contents of fouling and fouling substances were qualitatively and quantitatively analyzed by XRD and EDS respectively,and the formation of scale was observed by *** results show that with temperature increasing,Q235 steel is the most difficult to *** rate of all salt scales reaches a maximum after 12 h,and the fouling rate decreases significantly from 12 to 48 *** gradually stabilizes at 48 to 96 *** the roughness increasing,the thickness of fouling layer increases,and a linear relationship is presented for 1 to 10 *** comparing actual and simulated wastewater scaling rates,the relationship between actual and simulated wastewater scaling rates is y=*** composition of the scale was analyzed,calcium carbonate is the main product and increases with fouling *** on the above-mentioned results combining literatures,the hybrid prediction model with calcium carbonate as the main product is put *** is discussed microscopically that calcium carbonate is converted from aragonite and vaterite in a thermodynamically metastable state to calcite in a thermodynamically stable state.

关键词： Scaling Coal chemical wastewater Fouling rate Scaling model Calcium carbonate

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Sustainability of microporous polymers and their applications

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Science China Chemistry 2017年第8期60卷 1033-1055页

作者： Tamara l.Church Alma Berenice Jasso-Salcedo Fredrik Bjrnerbck Niklas Hedin Department of Materials and Environmental Chemistry Stockholm University SE-106 91 Stockholm Sweden

Microporous polymers(MPs) are studied for their intriguing chemistry and physics as well as their potential application in catalytic transformations, gas-separation processes, water purification and so on. Here, we critically review MPs with respect to the sustainability aspects of their synthesis as well as their applications that have sustainable character. Some MPs have been synthesized from monomers derived from biomass resources, but there is certainly a large potential for further *** are also opportunities to improve the sustainability of MP synthesis in terms of the use of solvents, catalysts, and related aspects. The applications of MPs in processes related to sustainability depend upon multiple properties. A rich and flexible chemistry is important to applications as catalysts for, among other useful reactions, the photoreduction of CO_2 and selective oxidation. The(ultra)micropore volume of MPs are crucial in gas-separation applications such as CO_2 capture, and the chemisorption of CO_2 on MP-tethered alkylamines could offer a means to remove that gas from dilute mixtures. When it comes to the storage of H_2 and CH_4 in MPs for onboard use in fuel cell or biogas cars, volumetric capacity is paramount, meaning that the density of the MPs must be considered. Finally, for use in separation and purifications from liquid mixtures(aqueous or hydrocarbon-based), crosslinked MPs are more limited than the solution-processable MPs that can be more easily processed into films and membranes.

关键词： microporous polymers biomass sustainability CO2 capture catalysis H2 storage CH4 storage separation purification

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Does nature-based solution sustain grassland quality? Evidence from rotational grazing practice in China

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Journal of Integrative Agriculture 2023年第8期22卷 2567-2576页

作者： lI Dong-qing ZHANG Ming-xue lü Xin-xin HOU ling-ling Institute of Agricultural Economics and Development Chinese Academy of Agricultural SciencesBejing 100081P.R.China China Center for Agricultural Policy School of Advanced Agricultural SciencesPeking UniversityBeijing 100871P.R.China

Rotational grazing is considered as one of the nature-based solutions(NbS)to grassland protection by natural ***,its effects on improving grassland quality are still unclear when it is adopted by *** a householdlevel panel data from field survey in two main pastoral provinces of China,empirical results from fixed-effect model and instrumental approach show that rotational grazing practices have insignificant short-term effects on grassland quality,but have positive long-term *** addition,rotational grazing practices can improve grassland quality when villages invest public infrastructure or herders have private supporting measures for more efficiency livestock *** analysis shows that herders adopting rotational grazing have higher grazing intensity,higher supplementary intensity and more livestock-house-feeding days,which indicate herders can utilize more efficient livestock management without increasing pressure on natural *** also find that herders with pastoral income are more likely to adopt rotational grazing *** insightful findings offer policy implications on promoting grassroot NbS for ecosystem protection and resource utilization in developing pastoral countries.

关键词： grassroots nature-based solutions rotational grazing grassland quality pastoral region China

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Delivery of Micro RNAs by plant virus-based nanoparticles to functionally alter the osteogenic differentiation of human mesenchymal stem cells

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Chinese Chemical letters 2023年第1期34卷 215-220页

作者： Fei Xue Jeroen J.l.M.Cornelissen Quan Yuan Shuqin Cao State Key laboratory of Oral Diseases West China Hospital of StomatologySichuan UniversityChengdu 610041China Department of Molecules&Materials MESA+Institute for NanotechnologyUniversity of TwenteEnschede AE 7500the Netherlands

Micro RNA-26a(miR-26a)has been verified to promote osteogenic differentiation of mesenchymal stem cells in recent *** main obstacles to its application in bone regeneration are instability in the physiological environment and low efficiency of cellular membrane *** overcome these problems,we constructed a novel plant virus gene delivery system based on Cowpea chlorotic mottle virus(CCMV).By encapsulating miR-26a with purified capsid protein(CP)dimers derived from CCMV,CPmiR-26a(CP26a)virus-like particles(VlPs)were ***26a retained a structure similar to the native CCMV and protected miR-26a from digestion with its exterior ***,CP26a featured similar cellular uptake efficiency,osteogenesis promotion ability,and better biocompatibility compared with lipofectamine2000-miR-26a(lipo26a),which indicated a promising prospect for CCMV as a novel gene delivery system.

关键词： VlPs Cowpea chlorotic mottle virus Gene delivery MicroRNAs Osteogenesis

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