检索结果-南通市图书馆

Chinese Journal of Catalysis 2020年第5期41卷 813-819页

作者： Hee Jin Kim Yong-Deok ahn Jeonghyeon Kim Kyoung-Su Kim Yeon Uk Jeong Jong wook Hong Sang-Il Choi Department of Chemistry and Green-Nano Materials Research Center Kyungpook National UniversityDaegu 41566Korea Department of Chemistry University of UlsanUlsan 44610Korea School of Materials Science and Engineering Kyungpook National UniversityDaegu 41566Korea

Bimetallic Pt-based catalysts have been extensively investigated to enhance the performance of direct methanol fuel cells(DMFCs) because CO, a by-product, reduces the activity of the pure Pt catalysts. Herein, we synthesized Pt-Pb hexagonal nanoplates as a model catalyst for the methanol oxidation reaction(MOR) and further controlled the Pt and Pb distributions on the surface of the nanoplates through acetic acid(HAc) treatment. As a result, we obtained Pt-Pb nanoplates and HAc-treated Pt-Pb nanoplates with homogeneous and heterogeneous distributions of the Pt-Pb alloy surfaces, respectively. We showed that the MOR activity and stability of the Pt-Pb nanoplates improved compared to those of the HAc-treated Pt-Pb nanoplates, mainly due to the enhanced CO tolerance and the modified electronic structure of Pt under the influence of the oxophilic Pb.

关键词： Platinum Lead Nanoplate Surface atomic distribution Methanol oxidation reaction

Hybrid Friction Stir Welding of High-carbon Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2011年第2期27卷 127-130页

作者： Don-Hyun Choi chang-Yong Lee Byung-wook ahn Jung-Hyun Choi Yun-Mo Yeon Keun Song Seung-Gab Hong Won-Bae Lee Ki-Bong Kang Seung-Boo Jung School of Advanced Materials Science and Engineering Sungkyunkwan University 300 Cheoncheon-dongJangan-guSuwonGyeonggi-do 440-746South Korea Department of Mechanical Engineering Korea Advanced Institute of Science and Technology 335 GwahangnoYuseong-guDaejeon 305-701South Korea Department of Advanced Materials Application Suwon Science College 9-10Botong-liJeongnam-myeonHwasungGyeonggi-do 445-742South Korea Technical Research Lab POSCO Corp.Goedong-dongNam-guPohangGyeongbuk790-785South Korea

A high-carbon steel joint,SK5（0.84 wt% C）,was successfully welded by friction stir welding（FSW）,both without and with a gas torch,in order to control the cooling rate during *** welding,the weld zone comprised gray and black regions,corresponding to microstructural variation：a martensite structure and a duplex structure of ferrite and cementite,*** volume fraction of the martensite structure and the Vickers hardness in the welds were decreased with the using of the gas torch,which was related with the lower cooling rate.

关键词： Friction stir welding High-carbon steel Transformation Martensite

^(27)Al MAS-NMR study of inorganic polymer formation at ambient temperature

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2011年第A01期21卷 182-187页

作者： Sang-wook ahn Hee-Soo LEE Wan-Hee YANG Jung-Woo LEE Young-Keun JEONG National Core Research Center for Hybrid Materials Solution Pusan National University School of Material Science and Engineering Pusan National University INTChem Co. Ltd.

Inorganic polymers are a novel class of materials formed by the polymerization of silicon, aluminium and oxygen species to form an amorphous three-dimensional framework structure. The basis of this process is the alkaline solutions to induce a certain amount of Si and AI atoms to dissolve from a feedstock such as aluminosilicate. A study of 27A1 MAS-NMR was carried out in an attempt to understand the reaction mechanism of the inorganic polymerization at ambient temperature. Scanning electron microscopy （SEM） and X-ray diflYactometry （XRD） were also employed to establish the composition and microstructure of the inorganic polymerization. Specimens were prepared with different A1/Si mole ratios from the starting materials. The higher the AI content, the more sufficient the AI atoms that can combine with SiO4, and the longer the reaction time, the more the bonded Si--O--A1--O polymer structure, and then the higher the A1 content, the fewer the octahedral A1 with a uniform Si--O--A1--O structure in four directions, because four AI atoms are combined with SiO4, resulting in a uniform Si--O--AI--O structure in four directions. The results show that they have an amorphous microstructure.

关键词： inorganic polymer amorphous tetrahedral

Metastatic liver cancer: A rare case

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2005年第27期11卷 4281-4284页

作者： Bong-Wan Kim Hee-Jung Wang In-Ho Jeong Sang-Ick ahn Myoung-wook Kim Department of Surgery

Hemangioperioltoma is a rare tumor especially when it rises in the peritoneal cavity. We present a case of a 60-year-old woman with an isolated recurrent hemangiopericytoma of the liver. The patient presented with a palpable right upper quadrant abdominal mass, which occurred 7 years after undergoing resection of a malignant hemangiopericytoma arising from the greater omentum. She had not followed up 6 mo after surgery. Various imaging studies showed a single large, well-capsulated liver tumor with central necrosis, accompanied by hypervascularity typical of a vascular tumor. Preoperative laboratory HBsAg and anti-HCV workup were both negative. Under the impression of recurrent malignant hemangiopericytoma, right trisegmentectomy was performed to completely resect the tumor. Pathological examination confirmed the diagnosis of recurrent hemangiopericytoma. Even though the incidence of the hemangiopericytoma is relatively low, malignant hemangiopericytoma has a tendency to recur frequently after a long-term disease-free interval. Also, the recurrent hemangiopericytoma is not easily detected early during follow-up until it becomes symptomatic because there are no specific tumor markers, and because of the diversity with regard to site of recurrence. The authors suggest that Positron Emission Tomogram （PET） may be a useful tool for the detection of recurrent hemangioperioltoma. We describe herein some characteristics and behaviors of malignant hemangiopericytoma, particularly after surgical resection.

关键词： Hemangiopericytoma Greater omentum Hepatic metastasis Follow-up Positron emission tomography

Enhanced charge separation by interchain hole delocalization in nonfullerene acceptor-based bulk heterojunction materials

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon Energy 2023年第7期5卷 27-37页

作者： chang-Mok Oh Sujung Park Jihoon Lee Sung Heum Park Shinuk Cho In-wook Hwang Advanced Photonics Research Institute Gwangju Institute of Science and TechnologyGwangjuRepublic of Korea Department of Physics and Energy Harvest Storage Research Center University of UlsanUlsanRepublic of Korea Department of Physics Pukyong National UniversityBusanRepublic of Korea

Bulk heterojunction(BHJ)composites show improved power conversion efficiencies when optimized in terms of morphology using various film processing methods.A reduced carrier recombination loss in an optimized BHJ was characterized ***,the driving force that leads to this reduction was not clearly *** this study,we focus on the decreased carrier recombination loss and its driving force in optimized nonfullerene acceptor-based PTB7-Th:IEICO-4F BHJ *** demonstrate that the optimized BHJ shows deactivation in the sub-nanosecond nongeminate carrier recombination *** driving force for this deactivation was determined to be the improved interchain hole delocalization between the *** enhanced interchain hole delocalization was observed using steady-state photoinduced absorption(PIA)*** particular,increased splitting between the polaron PIA bands was ***,improved interchain hole delocalization was observed for other state-of-the-art BHJ materials,including D18:Y6 with optimized morphologies.

关键词： bulk heterojunction interchain hole delocalization nonfullerene acceptor photoinduced absorption spectroscopy solar cell

Electrophoretic Deposition of Oxide Nanoparticles for Electron Emission Enhancement

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2010年第11期26卷 1032-1036页

作者： Jong Rok ahn Gil Seon Kang Hwack Joo Lee chang Joon Park Korea Research Institute of standards and Science

Four oxide nanoparticles,such as yttrium oxide,lanthanum oxide,cerium oxide and zirconium oxide were coated on rhenium filaments by an electrophoretic deposition *** oxide coatings were examined by scanning electron microscopy,and electron emission characteristics of the oxide-coated rhenium were studied to find alternative oxide materials for replacing the hazardous thorium *** four oxides tested in this work,yttrium oxide and lanthanum oxide coated rhenium showed enhanced electron emission compared with an uncoated ***,lanthanum oxide coating evaporated too quickly in a vacuum chamber,and hence yttrium oxide was found to be the only alternative material for use in a routine mass *** optimum coating thickness of the yttrium oxide and lanthanum oxide was around 20 μm.

关键词： Electrophoretic deposition Oxide nanoparticles Scanning electron microscopy (SEM) Electron emission

A Decade-old change in the Screening Rate for Hepatocellular Carcinoma Among a Hepatitis B Virus-infected Population in Korea

在线全文

学校读者我要写书评

暂无评论

Chinese Medical Journal 2016年第1期129卷 15-21页

作者： Hee Yeon Kim chang wook Kim Jong Young Choi Chung-Hwa Park chang Don Lee HyeonWoo Yim Department of Internal Medicine Division of Hepatology College of Medicine The Catholic University of Korea Seoul 06591 Republic of Korea Department of Internal Medicine Division of Hepatobiliary International St. Mary's Hospital Incheon 22711 Republic of Korea Department of Preventive Medicine College of Medicine The Catholic University of Korea Seoul 06591 Republic of Korea

Background： Evaluating a change in the screening rate for hepatocellular carcinoma （HCC） is critical for understanding screening implementation, and whether targeted population groups are receiving proper screening. This study examined recent nationwide changes in HCC screening use among hepatitis B virus （HBV）-infected populations after the introduction of the Korean National Cancer Screening Program and predictors of screening adherence. Methods： We analyzed 165 and 276 participants 〉40 years of age who were hepatitis B surface antigen-positive fiom 2001 （14,936 participants） to 2010-2011 （9159 participants） Korea National Health and Nutrition Examination Surveys, respectively. Demographic data, socioeconomic factors, and HCC screening use were collected by means of self-reported questionnaires. Results： The rate of HCC screening within the previous 2 years increased significantly from 17.5% in 2001 to 40.3% in 2010- 20I 1 （P〈 0.0001 ）. The rate of HCC screening use increased from 2001 to 2010-2011 in all study populations. Subjects who had a higher income staius and were aware of their infection were more likely to have undergone recent HCC screening. Conclusions： This study showed a substantial increase in HCC screening in high-risk HBV-infected subjects from 2001 to 2010-2011. However, the HCC screening participation rate remained suboptimal despite the introduction of the nationwide screening program. Efforts should be made to identiry high-risk individuals and increase attendance at HCC screening events among high-risk groups.

关键词： Carcinoma: Health Surveys: Hepatitis B: Hepatocellular Surveillance

Ischemic colitis after enema administration: Incidence, timing, and clinical features

在线全文

学校读者我要写书评

暂无评论

World Journal of Gastroenterology 2020年第41期26卷 6442-6454页

作者： Yura ahn Gil-Sun Hong Ju Hee Lee Choong wook Lee Seon-Ok Kim Department of Radiology and Research Institute of Radiology University of Ulsan College of Medicine&Asan Medical CenterSeoul 05505South Korea Department of Clinical Epidemiology and Biostatistics Asan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505South Korea

BACKGROUND Enema administration is a common procedure in the emergency department(ED). However, several published case reports on enema-related ischemic colitis(IC) have raised the concerns regarding the safety of enema agents. Nevertheless, information on its true incidence and characteristics are still *** To investigate the incidence, timing, and risk factors of IC in patients receiving *** We consecutively collected the data of all adult patients receiving various enema administrations in the ED from January 2010 to December 2018 and identified patients confirmed with IC following enema. Of 8320 patients receiving glycerin enema, 19 diagnosed of IC were compared with an age-matched control group without *** The incidence of IC was 0.23% among 8320 patients receiving glycerin enema;however, there was no occurrence of IC among those who used other enema agents. The mean age ± standard deviation(SD) of patients with glycerin enemarelated IC was 70.2 ± 11.7. The mean time interval ± SD from glycerin enema administration to IC occurrence was 5.5 h ± 3.9 h(range 1-15 h). Of the 19 glycerin enema-related IC cases, 15(79.0%) were diagnosed within 8 h. The independent risk factors for glycerin-related IC were the constipation score [Odds ratio(OR), 2.0;95% confidence interval(CI): 1.1-3.5, P = 0.017] and leukocytosis(OR, 4.5;95%CI: 1.4-14.7, P = 0.012).CONCLUSION The incidence of glycerin enema-related IC was 0.23% and occurred mostly in the elderly in the early period following enema administration. Glycerin enemarelated IC was associated with the constipation score and leukocytosis.

关键词： Enema Glycerin Ischemic colitis Incidence Timing Risk factors

A Spectral Iterative Method for the Computation of Effective Properties of Elastically Inhomogeneous Polycrystals

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Communications in Computational Physics 2012年第3期11卷 726-738页

作者： Saswata Bhattacharyya Tae wook Heo Kunok chang Long-Qing Chen Department of Materials Science and Engineering The Pennsylvania State UniversityUniversity ParkPA 16802USA

We report an efficient phase field formalism to compute the stress distribution in polycrystalline materials with arbitrary elastic inhomogeneity and *** dependence of elastic stiffness tensor on grain orientation is taken into account,and the elastic equilibrium equation is solved using a spectral iterative perturbation *** discuss its applications to computing residual stress distribution in systems containing arbitrarily shaped cavities and cracks(with zero elastic modulus)and to determining the effective elastic properties of polycrystals and multilayered composites.

关键词： Elasticity spectral method iterative method

Double cystic duct without being aware of the anatomic anomaly during laparoscopic cholecystectomy: The first case of reverse Y type anomaly

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Hepatobiliary & Pancreatic Diseases International 2021年第2期20卷 201-202页

作者： Suhyun Lim chang Hwan Kim Kwang Yeol Paik wook Kim Department of Surgery Yeouido St.Mary’s HospitalCollege of MedicineThe Catholic University of Korea#1063-roYeongdeungpo-guSeoul 07345Korea

To the Editor:Variations in cystic duct anatomy are quite common,but double cystic ducts arising from one gallbladder is extremely rare,which have only been reported in less than 20 cases in literature[1–4].It is difficult to diagnose the anatomic anomaly preoperatively,and the rate of open conversion and post-operation complications were high due to ductal injury during surgery[2].

关键词： anatomy cystic gallbladder