检索结果-南通市图书馆

Thermodynamic model for deoxidation of liquid steel considering strong metal-oxygen interaction in the quasichemical model framework

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 988-1002页

作者： Yong-Min cho youn-Bae Kang Graduate Institute of Ferrous and Eco Materials Technology Pohang University of Science and TechnologyPohangKyungbuk37673Rep.of Korea N.EX.T Hub POSCO HoldingsPohangKyungbuk37673Rep.of Korea Department of Materials Science and Engineering Pohang University of Science and TechnologyPohangKyungbuk37673Rep.of Korea

Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was *** model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for the minimization of internal Gibbs energy preliminarily when solving deoxidation *** elimination of internal Gibbs energy minimization is particularly advantageous during the coupling of deoxidation equilibrium calculations with computationally intensive approaches,such as computational fluid *** model enables efficient calculations through direct embedment of the explicit forms of activity coefficient in the computing *** proposed thermodynamic model was developed using a quasichemical approach with two key approximations:random mixing of metallic elements(Fe and oxidizing metal) and strong nonrandom pairing of metal and oxygen as nearest *** these approximations,the quasichemical approach yielded the activity coefficients of solutes as explicit functions of composition and temperature without requiring the minimization of internal Gibbs energy or the coupling of separate *** model was successfully applied in the calculation of deoxidation equilibria of various elements(Al,B,C,Ca,Ce,Cr,La,Mg,Mn,Nb,Si,Ti,V,and Zr).The limitations of the model arising from these assumptions were also discussed.

关键词： deoxidation equilibria thermodynamics quasichemical approach computational fluid dynamics

Crystallographically vacancy‐induced MOF nanosheet as rational single‐atom support for accelerating CO_(2)electroreduction to CO

在线全文

学校读者我要写书评

暂无评论

Carbon Energy 2024年第8期6卷 49-62页

作者： Jin Hyuk cho Joonhee Ma Chaehyeon Lee Jin Wook Lim youngho Kim Ho Yeon Jang Jaehyun Kim Myung‐gi Seo youngheon choi youn Jeong Jang Sang Hyun Ahn Ho Won Jang Seoin Back Jong‐Lam Lee Soo young Kim Department of Materials Science and Engineering Korea UniversitySeoulRepublic of Korea Department of Chemical and Biomolecular Engineering Sogang UniversitySeoulRepublic of Korea Department of Materials Science and Engineering Pohang University of Science and Technology(POSTECH)PohangRepublic of Korea Department of Materials Science and Engineering Research Institute of Advanced MaterialsSeoul National UniversitySeoulRepublic of Korea Lotte Chemical R&D Center DaejeonRepublic of Korea Department of Chemical Engineering Hanyang UniversitySeoulRepublic of Korea School of Chemical Engineering and Material Science Chung‐Ang UniversitySeoulRepublic of Korea

To attain a circular carbon economy and resolve CO_(2)electroreduction technology obstacles,single‐atom catalysts(SACs)have emerged as a logical option for electrocatalysis because of their extraordinary catalytic *** SACs,metal–organic frameworks(MOFs)have been recognized as promising support materials because of their exceptional ability to prevent metal *** study shows that atomically dispersed Ni single atoms on a precisely engineered MOF nanosheet display a high Faradaic efficiency of approximately 100%for CO formation in H‐cell and three‐compartment microfluidic flow‐cell reactors and an excellent turnover frequency of 23,699 h−1,validating their intrinsic catalytic *** results suggest that crystallographic variations affect the abundant vacancy sites on the MOF nanosheets,which are linked to the evaporation of Zn‐containing organic linkers during ***,using X‐ray absorption spectroscopy and density functional theory calculations,a comprehensive investigation of the unsaturated atomic coordination environments and the underlying mechanism involving CO^(*)preadsorbed sites as initial states was possible and provided valuable insights.

关键词： 2‐dimensional material carbon dioxide reduction metal-organic frameworks single‐atom catalysts vacancy sites

Numerical study on the heat dissipation characteristics of high-power LED module

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

Science China(Technological Sciences) 2013年第9期56卷 2150-2155页

作者： LEE DaeWoo cho sung-Wook KIM youn-Jea Graduate School of Mechanical Engineering Sungkyunkwan University School of Mechanical Engineering Sungkyunkwan University

LED lighting has problems such as short life span, power reduction due to the LED chip's heat, and decreased luminance efficiency etc. Many studies on the optimization of the thermal performance of LEDs have been conducted actively to solve these problems. The present study changes the fin shape and intervals of various heat sink designs so that LED can effectively produce a thermal effect. The water-cooling heat release system and the heat pipe methods show higher thermal performance results than the existing systems; however, the system is of high cost and requires a large-scale apparatus. This study carried out a numerical analysis of the thermal control system by applying heat flux and heat sink properties as an active heat release system using the commercial code ANSYS ver. 13.0 and verified the validity of the new heat sink design for temperature distribution analysis.

关键词： LED lighting water-cooling heat release system heat loss

Computational discovery of p-type transparent oxide semiconductors using hydrogen descriptor

在线全文

学校读者我要写书评

暂无评论

npj Computational Materials 2018年第1期4卷 503-509页

作者： Kanghoon Yim Yong youn Miso Lee Dongsun Yoo Joohee Lee sung Haeng cho Seungwu Han Department of Materials Science and Engineering and Research Institute of Advanced Materials Seoul National UniversitySeoul 08826Korea Electronics and Telecommunications Research Institute(ETRI) Daejeon 34129Korea Korea Institute of Energy Research Daejeon 34129Korea

The ultimate transparent electronic devices require complementary and symmetrical pairs of n-type and p-type transparent *** several n-type transparent oxide semiconductors like InGaZnO and ZnO are available and being used in consumer electronics,there are practically no p-type oxides that are comparable to the n-type counterpart in spite of tremendous efforts to discover ***,high-throughput screening with the density functional theory calculations attempted to identify candidate p-type transparent oxides,but none of suggested materials was verified experimentally,implying need for a better theoretical ***,we propose a highly reliable and computationally efficient descriptor for p-type dopability—the hydrogen impurity *** show that the hydrogen descriptor can distinguish well-known p-type and n-type *** the hydrogen descriptor,we screen most binary oxides and a selected pool of ternary compounds that covers Sn^(2+)-bearing and Cu^(1+)-bearing oxides as well as *** a result,we suggest La_(2)O_(2)Te and CuLiO as promising p-type oxides.

关键词： transparent semiconductors oxide

Probabilistic seismic performance assessment of lap-spliced RC columns retrofitted by steel wrapping jackets

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

Earthquake Engineering and Engineering Vibration 2016年第2期15卷 223-238页

作者： Eunsoo choi Heejung youn Baik-Soon cho Department of Civil Engineering Hongik University Department of Civil Engineering CTRCInje University

In this study, the seismic fragility curves of two reinforced concrete（RC） columns that were lap-spliced at the bottom and retrofitted with steel wrapping jackets were generated. Their seismic performance was probabilistically assessed in comparison to that of lap-spliced or continuous reinforcement RC columns. This study used two types of steel wrapping jackets, a full jacket and a split jacket. Analytical models of the four types of columns were developed based on the experimental results of the columns using Open SEES, which is effective in conducting nonlinear time history analyses. A suite of ten artificial ground motions, modified from recorded ground motions, was used to perform nonlinear time history analyses of the analytical models with scaling of the peak ground acceleration from 0.1 g to 1.0 g in increments of 0.1 g. The steel wrapping jackets did not increase the medians for yield（slight damage state） of the lap-spiced column and did not exceed the corresponding median of the continuous reinforcement column. However, the two steel jackets increased the medians for failure by 1.872 and 2.017 times, respectively, and exceeded the corresponding median of the continuous reinforcement column by 11.8% and 20.5%, respectively.

关键词： columns reinforcement reinforced exceed acceleration scaling median assessed split probabilistic

Treatment and prognosis of hepatic epithelioid hemangioendothelioma based on SEER data analysis from 1973 to 2014

在线全文

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2020年第1期19卷 29-35页

作者： O Kyu Noh Soon Sun Kim Min Jae Yang Sun Gyo Lim Jae Chul Hwang Hyo Jung cho Jae youn Cheong sung Won cho Department of Radiation Oncology Ajou University School of MedicineSuwonKorea Department of Biomedical Informatics Ajou University School of MedicineSuwonKorea Office of Biostatistics Ajou Research Institute for Innovative MedicineAjou University Medical CenterSuwonKorea Department of Gastroenterology Ajou University School of MedicineSuwonKorea

Background: Hepatic epithelioid hemangioendothelioma (HEH) is a rare tumor of vascular origin with an unknown etiology, a low incidence, and a variable natural course. We evaluated the management and prognosis of HEH from the Surveillance, Epidemiology and End Results (SEER) program and changes in treatment modalities of HEH over 30 years. Methods: From 1973 to 2014 in the SEER database, we selected patients diagnosed with HEH. We analyzed the clinical characteristics, patterns of management, and clinical outcomes of patients with HEH. Results: We identi ed 79 patients with HEH (median age: 54.0 years;male to female ratio: 1:2.6). The initial extent of disease was local in 22 (27.8%) patients, regional metastasis in 22 (27.8%), distant metas-tasis in 31 (39.2%) and unknown in 4 (5.1%). The median size of primary tumor was 3.85 cm (interquartile range, 2.50 7.93 cm). Among 74 patients with available management data, the most common manage-ment was no treatment (29/74, 39.2%), followed by chemotherapy only (22/74, 29.7%), liver resection-based (13/74, 17.6%), and transplantation-based therapy (6/74, 8.1%). The 5-year cancer-speci c survival rate was 57.8%. Patients who underwent surgical treatment had signi cantly higher survival than those who underwent non-surgical treatment (5-year survival;88% vs. 49%, P=0.019). Multivariate analysis revealed that surgical therapy was the only independent prognostic factor for survival (hazard ratio: 0.20, P=0.040). Conclusions: Resection or liver transplantation is worth considering for treatment of patients with HEH.

关键词： Hemangioendothelioma Epithelioid SEER program Liver transplantation Hepatectomy Liver neoplasms

Newly-modeled graphene-based ternary nanocomposite for the magnetophotocatalytic reduction of CO_(2) with electrochemical performance

在线全文

学校读者我要写书评

暂无评论

Frontiers of Chemical Science and Engineering 2022年第10期16卷 1438-1459页

作者： Zambaga Otgonbayar Kwang youn cho chong-Hun Jung Won-Chun Oh Department of Advanced Materials Science&Engineering Hanseo UniversitySeosan-Si 31962Korea Korea Institutes of Ceramic Engineering and Technology Jinju-Si 660031Korea Decommissioning Technology Research Division Korea Atomic Energy Research InstituteDaejeon 305-600Korea Anhui International Joint Research Center for Nano Carbon-based Materials and Environmental Health College of Materials Science and EngineeringAnhui University of Science&TechnologyHuainan 232001China

The development of CO_(2)into hydrocarbon fuels has emerged as a green method that could help mitigate global *** novel structured photocatalyst is a promising material for use in a photocatalytic and magneto-electrochemical method that fosters the reduction of CO_(2)by suppressing the recombination of electron−hole pairs and effectively transferring the electrons to the surface for the chemical reaction of CO_(2)*** our study,we have developed a novel-structured AgCuZnS_(2)–graphene–TiO_(2)to analyze its catalytic activity toward the selective evolution of CO_(2).The selectivity of each nanocomposite substantially enhanced the activity of the AgCuZnS_(2)–graphene–TiO_(2)ternary nanocomposite due to the successful interaction,and the selectivity of the final product was improved to a value 3 times higher than that of the pure AgCuZnS_(2)and 2 times higher than those of AgCuZnS_(2)–graphene and AgCuZnS_(2)–TiO_(2)under ultraviolet(UV)-light(λ=254 nm)irradiation in the photocatalytic *** electrochemical CO_(2)reduction test was also conducted to analyze the efficacy of the AgCuZnS_(2)–graphene–TiO_(2)when used as a working electrode in laboratory electrochemical *** electrochemical process was conducted under different experimental conditions,such as various scan rates(mV·s^(–1)),under UV-light and with a 0.07 T *** evolution of CO_(2)substantially improved under UV-light(λ=254 nm)and with 0.07 T magnetic-core treatment;these improvements were attributed to the facts that the UV-light activated the electron-transfer pathway and the magnetic core controlled the pathway of electrontransmission/prevention to protect it from chaotic electron *** all tested nanocomposites,AgCuZnS_(2)–graphene–TiO_(2)absorbed the CO_(2)most strongly and showed the best ability to transfer the electron to reduce the CO_(2)to *** believe that our newly-modeled ternary nanocomposite opens up new opportunities for the evolution of C

关键词： ternary nanocomposite photocatalytic electrochemical CO_(2) reduction UV-light magnetic core

Enhancing ammonia production rates from electrochemical nitrogen reduction by engineering three-phase boundary with phosphorus-activated Cu catalysts

在线全文

学校读者我要写书评

暂无评论

Journal of Energy Chemistry 2023年第9期84卷 394-401页

作者： Jeehye Kim cho Hee Lee Yong Hyun Moon Min Hee Lee Eun Hyup Kim Sun Hee choi youn Jeong Jang Jae sung Lee School of Energy and Chemical Engineering Ulsan National Institute of Science and Technology(UNIST)Ulsan 44919Republic of Korea Department of Chemical Engineering Hanyang UniversitySeoul 04763Republic of Korea Pohang Accelerator Laboratory(PAL) Pohang University of Science and Technology(POSTECH)Pohang 37673Republic of Korea

Electrochemical N_(2) reduction reaction(eNRR) over Cu-based catalysts suffers from an intrinsically low activity of Cu for activation of stable N_(2) molecules and the limited supply of N_(2) to the catalyst due to its low solubility in aqueous ***,we propose phosphorus-activated Cu electrocatalysts to generate electron-deficient Cu sites on the catalyst surface to promote the adsorption of N_(2) *** eNRR system is further modified using a gas diffusion electrode(GDE) coated with polytetrafluoroethylene(PTFE) to form an effective three-phase boundary of liquid water-gas N_(2)-solid catalyst to facilitate easy access of N_(2) to the catalytic *** a result,the new catalyst in the flow-type cell records a Faradaic efficiency of 13.15% and an NH_(3) production rate of 7.69 μg h^(-1) cm^(-2) at-0.2 V_(RHE),which represent 3.56 and 59.2 times increases from those obtained with a pristine Cu electrode in a typical electrolytic *** work represents a successful demonstration of dual modification strategies;catalyst modification and N_(2) supplying system engineering,and the results would provide a useful platform for further developments of electrocatalysts and reaction systems.

关键词： Electrochemical nitrogen reduction reaction Ammonia production Phosphorous modified copper electrodes Gas diffusion electrodes Three-phase boundary PTFE coating

Effect of heating rate on the properties of silicon carbide fiber with chemical-vapor-cured polycarbosilane fiber

在线全文

学校读者我要写书评

暂无评论

Journal of Advanced Ceramics 2017年第1期6卷 59-66页

作者： Tae-Eon KIM Khos-Erdene KHISHIGBAYAR Kwang youn cho Ceramic Fiber and Composite Materials Center Korea Institute of Ceramic Engineering and Technology 101 Soho-ro Jinju-si Gyeongsangnam-do 660-031 R.O.Korea

Silicon carbide (SiC) fiber has recently received considerable attention as promising next-generation fiber because of its high strength at temperatures greater than 1300 ℃ in ***-quality SiC fiber is primarily made through a curing and heat treatment *** this study,the chemical vapor curing method,instead of the thermal oxidation curing method,was used to prepare cured polycarbosilane (PCS) *** the high temperature heat treatment of the cured PCS fiber,varied heating rates of 10,20,30,and 40 ℃/min were *** the process,the fiber remained in the amorphous silicon carbide phase,and the measured tensile strength was the greatest when the oxygen content in the heat-treated fiber was low,due to the rapid heating *** fiber produced through this method was also found to have excellent internal oxidation *** fast,continuous process shows a great promise for the production of SiC fiber and the development of high-quality products.

关键词： polycarbosilane (PCS) silicon carbide (SiC) fiber chemical vapor curing rapid heating rate high temperature tensile strength