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Influence of undissolved second-phase particles on dynamic recrystallization behavior of Mg–7Sn–1Al–1Zn alloy during low-and high-temperature extrusions

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Journal of Materials Science & Technology 2021年第12期71卷 87-97页

作者： hyun Ji Kim Sang-Cheol Jin jae-Gil Jung Sung Hyuk Park School of Materials Science and Engineering Kyungpook National UniversityDaegu41566Republic of Korea Implementation Research Division Korea Institute of Materials ScienceChangwon51508Republic of Korea

This study investigates the effects of fine and coarse undissolved particles in a billet of the Mg–7 Sn–1 Al–1 Zn(TAZ711)alloy on the dynamic recrystallization(DRX)behavior during hot extrusion at low and high temperatures and the resultant microstructure and mechanical properties of the *** this end,partially homogenized(PH)and fully homogenized(FH)billets are extruded at temperatures of250 and 450°*** PH billet contains fine and coarse undissolved Mg_(2) Sn particles in the interdendritic region and along the grain boundaries,*** fine particles(han that fabricated using the FH billet,which is virtually devoid of second-phase *** lower strength of the former is attributed mai

关键词： Mg–Sn alloy Second-phase particle Extrusion Homogenization Dynamic recrystallization

Sodium nitrite-derived nitric oxide protects rat testes against ischemia/reperfusion injury

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Asian Journal of Andrology 2019年第1期21卷 92-97页

作者： jae Won Lee Dong-Hun Lee jae Keun Park Jin Soo han Center for Convergence Bioceramic Materials Korea Institute of Ceramic Engineering and TechnologyChungcheongbuk-do 28160Korea Department of Awan Diseases Laboratory College of Veterinary MedicineKonkuk UniversitySeoul 05029Korea Viral Pathogenesls Section Laboratory of Infectious DiseasesNational Institute of Allergy and infectious DiseasesNational institutes of HealthBethesdaMD 20892USA The institute for the 3Rs & Department of Laboratory Animal Medicine College of Veterinary Medicine and Veterinary Science Research instituteKonkuk UniversitySeoul 05029Korea.

Testicular torsion,a common urologic emergency,is primarily caused by ischemia/reperfusion (I/R)injury of the *** oxide (NO)-derived from nitrite (NO2-)has been reported to have prominent therapeutic effects on I/R injury in the heart,liver,and brain;however,its effects on testicular I/R injury have not been *** study,therefore,investigated whether NO from NO2^-is beneficial in a rat model of testicular I/R injury which eventually results in impaired *** Sprague-Dawley rats were assigned to the following seven groups:group A,sham-operated control group;Group B,I/R with no treatment;Groups C, D,and E,I/R followed by treatment with three different doses of NO2^-;Group F,I/R followed by administration of NO2-and NO scavenger (2-(4-carboxyphenyl)-4,4,5,5-tetramethylimidazoline-l-oxyl-3-oxide potassium salt [C-PTIO]);and Group G,I/R followed by administration of nitrate (NO3^-).NO2^-,NO3^-,and C-PTIO were intravenously *** examination of the testes and the western blot analysis of caspase-3 were *** of antioxidant enzymes and lipid peroxidation were measured. Germ cell apoptosis,oxidative stress,antioxidant enzymatic function,and lipid peroxidation in Group B were significantly higher than those in Group *** B exhibited an abnormal testicular morphology and impaired *** contrast,testicular damages were attenuated in the NO2^-treatment groups,which were caused by reduction in superoxide and peroxynitrite levels and an inhibition of caspase-3-dependent *** results of this study suggest NO2^-to be a promising therapeutic agent with anti-oxidant and anti-apoptotic properties in testicular I/R injury.

关键词： ischemia/reperfusion injury nitric oxide nitrite rat testis

Clinical outcome of Fitz-Hugh-Curtis syndrome mimicking acute biliary disease

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World Journal of Gastroenterology 2008年第45期14卷 6975-6980页

作者： Seong Yong Woo Jin Il Kim Dae Young Cheung Se hyun Cho Soo-Heon Park Joon-Yeol han jae Kwang Kim Division of Gastroenterology and Hepatology Department of Internal Medicine the Catholic University of Korea

AIM: To analyze the clinical characteristics of patients diagnosed with Fitz-Hugh-Curtis ***: The clinical courses of patients that visited St. Mary's Hospital with abdominal pain from January 2005 to December 2006 and were diagnosed with Fitz-Hugh-Curtis syndrome were ***: Fitz-Hugh-Curtis syndrome was identified in 22 female patients of childbearing age; their mean age was 31.0 ± 8.1 years. Fourteen of these cases presented with pain in the upper right abdomen alone or together with pain in the lower abdomen, and six patients presented with pain only in the lower abdomen. The first impression at the time of visit was acute cholecystitis or cholangitis in 10 patients and acute appendicitis or pelvic inflammatory disease in eight patients. Twenty-one patients were diagnosed by abdominal computer tomograghy (CT), and the results of abdominal sonography were normal for 10 of these patients. Chlamydia trichomatis was isolated from 18 patients. Two patients underwent laparoscopic adhesiotomy and 20 patients were completely cured by antibiotic ***: For women of childbearing age with acute pain in the upper right abdomen alone or together with pain in the lower abdomen, Fitz-Hugh-Curtis syndrome should be considered during differential diagnosis. Moreover, in cases suspected to be Fitz-Hugh-Curtis syndrome, abdominal CT, rather than abdominal sonography, assists in the diagnosis.

关键词： Chlamydia trichomatis Abdominal pain Fitz-Hugh-Curtis syndrome

Superelastic metastable Ti-Mo-Sn alloys with high elastic admissible strain for potential bio-implant applications

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Journal of Materials Science & Technology 2023年第32期163卷 45-58页

作者： Shuanglei Li jae H.Kim Seung Won Kang jae Ho Kim Tae-hyun Nam Jong-Taek Yeom Titanium Alloys Department Metal Materials DivisionKorea Institute of Materials Science(KIMS)Changwon 51508Republic of Korea Department of Materials Engineering and Convergence Technology&Research Institute for Green Energy Convergence Technology(RIGET) Gyeongsang National University900 GazwadongJinjuGyeongnam 52828Republic of Korea

The demand for titanium alloys simultaneously having high elastic admissible strain and large recovery strain for bio-implant applications is ***-free Ti-based shape memory alloys are promising candidates for obtaining the required multifunctional *** this study,a wide content range of(0-15)wt%of low-cost,toxicity-free,and high-biocompatible Sn element was added to the Ti-8Mo(wt%)alloy to study its effect on the superelastic recovery and mechanical properties of biomedical Ti-Mo-Sn *** tailoring Sn content,desired multifunctional properties of high elastic admissible strain and room temperature superelasticity were achieved in the studied Ti-Mo-Sn *** was found that the increase in Sn content stabilized theβphase and a singleβphase was obtained at room temperature in Ti-8Mo-(13,15)Sn *** addition of Sn modified the lattice parameters of theα″martensite andβphase and affected the lattice deformation stain ofβ→α″.The lattice deformation strain along the[011]βdirection was found to be decreased by-0.26%/wt%*** room temperature superelasticity with a recovery strain of 3.1%and an elastic admissible strain of 1%was obtained in the Ti-8Mo-13Sn *** Sn content increased to 15 wt%,a high elastic admissible strain of 1.56%and a recovery strain of 2.0%were *** Ti-Mo-Sn alloys with excellent multifunctional properties are promising candidates for bio-implant applications.

关键词： Ti-Mo-Sn alloy Shape memory alloy Elastic admissible strain Elastic modulus Superelasticity

Intraoperative neurophysiological monitoring in spinal surgery

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World Journal of Clinical Cases 2015年第9期3卷 765-773页

作者： Jong-Hwa Park Seung-jae hyun Department of Neurosurgery Spine CenterSeoul National University Bundang Hospital Seoul National University College of Medicine

Recently, many surgeons have been using intraoperative neurophysiological monitoring(IOM) in spinal surgery to reduce the incidence of postoperative neurological complications, including level of the spinal cord, cauda equina and nerve root. Several established technologies are available and combined motor and somatosensory evoked potentials are considered mandatory for practical and successful IOM. Spinal cord evoked potentials are elicited compound potentials recorded over the spinal cord. Electrical stimulation is provoked on the dorsal spinal cord from an epidural electrode. Somatosensory evoked potentials assess the functional integrity of sensory pathways from the peripheral nerve through the dorsal column and to the sensory cortex. For identification of the physiological midline, the dorsal column mapping technique can be used. It is helpful for reducing the postoperative morbidity associated with dorsal column dysfunction when distortion of the normal spinal cord anatomy caused by an intramedullary cord lesion results in confusion in localizing the midline for the myelotomy. Motor evoked potentials(MEPs) consist of spinal, neurogenic and muscle MEPs. MEPs allow selective and specific assessment of the functional integrity of descending motor pathways, from the motor cortex to peripheral muscles. Spinal surgeons should understand the concept of the monitoring techniques and interpret monitoring records adequately to use IOM for the decision making during the surgery for safe surgery and a favorable surgical outcome.

关键词： Motor-evoked potentials Somatosensoryevoked potentials Intraoperative neurophysiological monitoring Direct wave Spinal surgery

Electrochemically Deposited CZTSSe Thin Films for Monolithic Perovskite Tandem Solar Cells with Efficiencies Over 17%

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Energy & Environmental Materials 2024年第1期7卷 147-152页

作者： Sun Kyung Hwang Ik jae Park Se Won Seo jae hyun Park So Jeong Park Jin Young Kim Department of Materials Science and Engineering Seoul National UniversitySeoul 08826Korea Department of Applied Physics Sookmyung Women's UniversitySeoul 04310Korea Research Institute of Advanced Materials and Systems Sookmyung Women's UniversitySeoul 04310Korea Research Institute of Advanced Materials(RIAM) Seoul National UniversitySeoul 08826Korea

In spite of the high potential economic feasibility of the tandem solar cells consisting of the halide perovskite and the kesterite Cu2ZnSn(S,Se)4(CZTSSe),they have rarely been demonstrated due to the difficulty in implementing solution-processed perovskite top cell on the rough surface of the bottom ***,we firstly demonstrate an efficient monolithic two-terminal perovskite/CZTSSe tandem solar cell by significantly reducing the surface roughness of the electrochemically deposited CZTSSe bottom *** surface roughness(R_(rms))of the CZTSSe thin film could be reduced from 424 to 86 nm by using the potentiostatic mode rather than using the conventional galvanostatic mode,which can be further reduced to 22 nm after the subsequent ion-milling *** perovskite top cell with a bandgap of 1.65 eV could be prepared using a solution process on the flattened CZTSSe bottom cell,resulting in the efficient perovskite/CZTSSe tandem solar *** the current matching between two subcells involving the thickness control of the perovskite layer,the best performing tandem device exhibited a high conversion efficiency of 17.5%without the hysteresis effect.

关键词： CZTSSe monolithic tandem solar cells perovskite solution process surface roughness control

Effects of structure and electronic properties of D-π-A organic dyes on photovoltaic performance of dye-sensitized solar cells

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Journal of Energy Chemistry 2021年第3期30卷 208-216页

作者： Min-Woo Lee jae-Yup Kim hyung-Geun Lee hyun Gil Cha Duck-hyung Lee Min jae Ko Bio-Based Chemistry Research Center Advanced Convergent Chemistry DivisionKorea Research Institute of Chemical Technology(KRICT)Ulsan 44429Republic of Korea Department of Chemical Engineering Dankook UniversityYongin 16890Republic of Korea Department of Chemistry Sogang UniversitySeoul 04107Republic of Korea Department of Chemical Engineering Hanyang UniversitySeoul 04763Republic of Korea Institute of Nano Science and Technology Hanyang UniversitySeoul 04763Republic of Korea

Herein,we examine the performance of dye-sensitized solar cells containing five D-π-A organic dyes designed by systematic modification of π-bridge size and geometric *** dye has a simple push-pull structure with a triarylamino group as an electron donor,bithiophene-4,4-dimethyl-4 H-cyclopenta 1,2-b:5,4-b’]dithiophene(M11),4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophenethiophene(M12),thiophene-4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene(M13),4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene-benzene(M14),and 4,4-dimethyl-4 H-cyclopenta[1,2-b:5,4-b’]dithiophene(M15)units asπ-bridges,and cyanoacrylic acid as an electron acceptor/*** extension of theπ-bridge linkage favors wide-range absorption but,because of the concomitant molecular volume increase,hinders the efficient adsorption of dyes on the TiO_(2) film ***,higher loadings are achieved for smaller dye molecules,resulting in(i)a shift of the TiO_(2) conduction band edge to more negative values,(ii)a greater photocurrent,and(iii)suppressed charge recombination between the photoanode and the redox couple in the ***,under one-sun equivalent illumination(AM 1.5 G,100 mW/cm^(2)),the highest photovoltage,photocurrent,and conversion efficiency(η=7.19%)are observed for M15,which has the smallest molecular volume among M series dyes.

关键词： Dye-sensitized solar cells Donor-acceptor dyes Electron-rich unit Wide-range absorption Impedance spectroscopy

Complications and management of forgotten long-term biliary stents

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World Journal of Gastroenterology 2017年第4期23卷 622-628页

作者： Se Hoon Sohn jae hyun Park Kook hyun Kim Tae Nyeun Kim Division of Gastroenterology and Hepatology Department of Internal MedicineYeungnam University College of MedicineDaegu 42415South Korea

AIMTo evaluate complications and management outcomes of retained long-term plastic biliary *** plastic biliary stent placement was performed in 802 patients at Yeungnam University Hospital between January 2000 and December 2014. Follow-up loss with a subsequently forgotten stent for more than 12 mo occurred in 38 patients. We retrospectively examined the cause of biliary stent insertion, status of stents, complications associated with biliary stents and management outcomes of long-term plastic biliary stents. Continuous variables were analyzed using the t test. Observed frequencies in subsets of the study population were compared using Fisher’s exact test and χ2 tests. Statistical significance was defined as P han 24 mo. Common bile duct (CBD) stones or sludge were found in most cases (92.1%, 35/38). The most common complication was acute cholangitis (94.7%, 36/38). Stent removal by endoscopic approach was successfully performed in 92.1% (35/38) of the cases. In 3 cases, an additional plastic stent was inserted alongside the previous stent due to failure of the stent removal. Endoscopic removal of bile duct stones was successful in 73.7% (28/38) of the cases. When patients were divided into two groups by duration of stent placement (12 to 24 mo vs over 24 mo), there were no differences in the development of cholangitis, presence of biliary stones, and success rate of endoscopic removal of stones and biliary *** most common complication of retained long-term plastic biliary stents was acute cholangitis associated with CBD stones. Endos

关键词： Biliary stent Long-term complications Forgotten stents Acute cholangitis Biliary stone

Innovative strategies toward challenges in PV-powered electrochemical CO_(2)reduction

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Journal of Energy Chemistry 2021年第9期30卷 410-416页

作者： Siraj Sultan Jin hyun Kim Seung Hyeon Kim Youngkook Kwon jae Sung Lee Department of Energy Engineering School of Energy and Chemical EngineeringUlsan National Institute of Science and Technology(UNIST)Ulsan 44919South Korea

The solar energy-driven electrochemical CO_(2)reduction to value-added fuels or chemicals is considered as an attractive path to store renewable energy in the form of chemical energy to close the carbon ***,CO_(2)reduction suffers from a number of challenges including slow reaction rates,low selectivity,and low energy conversion ***,innovative strategies have been developed to mitigate this *** the development of flow cell reactors with a gas diffusion electrode,ionic liquid electrolytes,and new electrocatalysts have dramatically improved the reaction rates and selectivity to desired *** this perspective,we highlight the key recent developments and challenges in PVpowered electrochemical CO_(2)reduction and propose effective strategies to improve the reaction kinetics,to minimize the electrical energy losses,and to tune the selectivity of the catalysts for desired products,and then suggest future direction of research and development.

关键词： Electrochemical CO_(2)reduction Photovoltaic cell Ionic liquid electrolytes Flow cell electrolyzers Gas diffusion electrode