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Cobalt phosphide nanoarrays with crystalline-amorphous hybrid phase for hydrogen production in universal-pH

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Nano Research 2020年第9期13卷 2469-2477页

作者： Hyunseok yoon Hee Jo Song Bobae Ju Dong-Wan kim School of Civil Environmental and Architectural EngineeringKorea UniversitySeoul 02841Republic of Korea

To accomplish mass hydrogen production by electrochemical water-splitting,it is a necessary to develop robust,highly active,stable,and cost-effective hydrogen evolution reaction(HER)electrocatalysts that perform comparably to Pt in the universal pH *** this work,cobalt phosphide hybrid nanosheets supported on carbon felt(CoP HNS/CF)are presented,which exhibit the superior electrocatalytic hydrogen production under a *** these nanosheets,a single CoP HNS is composed of polycrystalline CoP and oxygen-enriched amorphous Co-O-P *** from its unique nanoarchitecture,as-fabricated CoP HNS/CF exhibits a tremendous electrocatalytic HER activity and outperforms Pt/C as well as state-of-the-art CoP electrocatalysts in *** acidic and neutral media,the CoP HNS/CF shows superior electrocatalytic activity while maintaining its original hybrid crystalline-amorphous phase and *** alkaline medium,the unexpected phase and morphological reorganization of CoP HNS/CF results in outstanding electrocatalytic *** HNS/CF not only achieves high electrocatalytic activity and kinetics,but also a stable and long operating lifetime even under a high current density of 500 mA cm'***,the fabrication of CoP HNS/CF can be scaled up easily,and the large CoP HNS/CF electrode also exhibits similar electrocatalytic activity and stability.

关键词： cobalt phosphide self-supporting electrocatalyst hydrogen evolution reaction universal-ph large-scale

Ion shielding functional separator using halloysite containing a negative functional moiety for stability improvement of Li–S batteries

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Journal of Energy Chemistry 2021年第9期30卷 334-340页

作者： Yong Min Kwon Jihoon kim Kuk Young Cho Sukeun yoon Division of Advanced Materials Engineering&Institute for Rare Metals Kongju National UniversityChungnam 31080Republic of Korea Department of Materials Science and Chemical Engineering Hanyang UniversityGyeonggi 15588Republic of Korea

Lithium–sulfur batteries are one of the attractive next-generation energy storage systems owing to theienvironmental friendliness,low cost,and high specific energy ***,the low electrical conductivity of sulfur,shuttling of soluble intermediate polysulfides between electrodes,and low capacitretention have hampered their commercial *** address these issues,we use a halloysitemodulated(H-M)separator in a lithium–sulfur battery to mitigate the shuttling *** H-M separator acts as a mutual Coulombic repulsion in lithium-sulfur batteries,thereby selectively permitting Lions and efficiently suppressing the transfer of undesired lithium polysulfides to the Li anode sideMoreover,the use of halloysite switches the surface of the separator from hydrophobic to hydrophilicconsequently improving the electrolyte wettability and adhesion between the separator and cathodeWhen sulfur-multi-walled carbon nanotube(S-MWCNT)composites are used as cathode active materialsa lithium–sulfur battery with an H-M separator exhibits first discharge and charge capacities of 1587 an1527 m Ah g-1,***,there is a consistent capacity retention up to 100 cyclesAccordingly,our approach demonstrates an economical and easily accessible strategy for commercialization of lithium–sulfur batteries.

关键词： Li–S batteries Halloysite Ion shielding Negative functional moiety Lithium polysulfides

Corrosion and optimum corrosion protection potential of friction stir welded 5083-O Al alloy for leisure ship

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中国有色金属学会会刊：英文版 2009年第4期19卷 898-903页

作者： Sung-Hyeon PARK Jong-shin kim Min-Su HAN Seong-Jong kim Division of Maritime Transportation System Mokpo Maritime University Korea Register of Shipping Division of Marine Engineering Mokpo Maritime University

Electrochemical tests were undertaken to determine the optimum conditions in seawater for corrosion protection of friction stir-welded 5083-O Al *** trend observations show that the limiting potential that avoids the effects of hydrogen embrittlement is -1.6 V,corresponding to the crossover point between concentration polarization and activation ***,the optimum protection potential is between -1.5 and -0.7 V since the current density at these values is low in the potentiostatic *** a galvanic cell is formed in the seawater,the welds exhibit electrochemically stable *** parts in galvanic tests with various area ratios are stable and have excellent anticorrosion characteristics.

关键词：搅拌摩擦焊接保护电位海水腐蚀铝合金氧铝船舶休闲防腐

Electrical characteristics and detailed interfacial structures of Ag/Ni metallization on polycrystalline thermoelectric SnSe

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Journal of Materials Science & Technology 2019年第5期35卷 711-718页

作者： Yeongseon kim Younghwan Jin Giwan yoon In Chung Hana yoon Chung-Yul Yoo Sang Hyun Park Separation and Conversion Materials Laboratory Korea Institute of Energy Research 152 Gajeong-ro Yuseong-gu Daejeon 34129 Republic of Korea School of Electrical Engineering Korea Advanced Institute of Science and Technology 291 Daehak-ro Yuseong-gu Daejeon 34142 Republic of Korea Department of Physics Chungnam National University 99 Daehak-ro Yuseong-gu Daejeon 34134 Republic of Korea School of Chemical and Biological Engineering Seoul National University 1 Gwanak-ro Gwanak-gu Seoul 08826 Republic of Korea

SnSe is a promising thermoelectric material with a high figure of merit in single crystal form, which has stimulated continuous research on polycrystalline SnSe. In this study, we investigated a metallization techniques for polycrystalline SnSe to achieve highly efficient and practical SnSe thermoelectric modules. The Ag/Ni metallization layers were formed on pristine polycrystalline SnSe using various deposition technique: sputter coating Ni, powder Niand foil Ni by spark plasma sintering. Structural analysis demonstrated that the microstructure and con tact resistance could be different according to the metallization process, despite using the same metals. The Ag/Ni metallization layer using foil Ni acted as an effective diffusion barrier and minimized electrical contact resistance (2.3×10^-4Ωcm^2). A power loss in the thermoelectric module of only 5% was demonstrated using finite element simulation.

关键词： Thermoelectric Metallization Electric contact material Interface microstructure SnSe

Reactive Core-Shell Bottlebrush Copolymer as Highly Effective Additive for Epoxy Toughening

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Chinese Journal of Polymer Science 2021年第12期39卷 1626-1633页

作者： Junsoo Moon yoon Huh Seonghwan kim Youngson Choe Joona Bang Department of Chemical and Biological Engineering Korea UniversitySeoul 02841Republic of Korea Department of Chemical Engineering Pusan National UniversityPusan 46241Republic of Korea

Herein,we designed a core-shell structured bottlebrush copolymer(BBP),which is composed of rubbery poly(butyl acrylate)(PBA)core and an epoxy miscible/reactive poly(glycidyl methacrylate)(PGMA)shell,as an epoxy tougheni ng age *** PGMA shell allows BBP to be uniformly dispersed within the epoxy matrix and to react with the epoxy groups,while the rubbery PBA block simultaneously induced nanocavitation effect,leading to improvement of mechanical properties of the epoxy *** mechanical properties were measured by the adhesion performance test,and the tensile and fracture test using universal testing *** BBP additives were added to the epoxy resin,a sign ifica nt improveme nt in the adhesion stren gth(2-fold increase)and fracture toughness(2-fold in crease in Kic and 5-fold in crease in Gic)compared to the neat epoxy was *** contrast,linear additives exhibited a decrease in adhesion strength and no improvement of fracture toughness over the neat *** a difference in mechanical performance was investigated by comparing the morphologies and fracture surfaces of the epoxy resins containing linear and BBP additives,confirming that the nanocavitation effect and void formation play a key role in strengthening the BBP-modified epoxy resins.

关键词： Bottlebrush polymer ROMP Additive Adhesion Epoxy toughening

Osteoporosis and bone fractures in alcoholic liver disease:A meta-analysis

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World Journal of Gastroenterology 2015年第13期21卷 4038-4047页

作者： Chang Seok Bang In Soo shin Sung Wha Lee Jin Bong kim Gwang Ho Baik Ki Tae Suk Jai Hoon yoon Yeon Soo kim Dong Joon kim Department of Internal Medicine Hallym University College of MedicineChuncheon 200-704South Korea College of Education Jeonju UniversityJeonju 560-759South Korea

AIM: To evaluate the association between alcoholic liver disease(ALD) and bone fractures or osteoporosis. METHODS: Non-randomized studies were identified from databases(Pub Med, EMBASE, and the Cochrane Library). The search was conducted using Boolean operators and keywords, which included "alcoholic liver diseases", "osteoporosis", or "bone fractures". The prevalence of any fractures or osteoporosis, and bone mineral density(BMD) were extracted and analyzed using risk ratios and standardized mean difference(SMD). A random effects model was applied. RESULTS: In total, 15 studies were identified and analyzed. Overall, ALD demonstrated a RR of 1.944(95%CI: 1.354-2.791) for the development of bone fractures. However, ALD showed a RR of 0.849(95%CI: 0.523-1.380) for the development of osteoporosis. BMD was not significantly different between the ALD and control groups, although there was a trend toward lower BMD in patients with ALD(SMD in femur-BMD:-0.172, 95%CI:-0.453-0.110; SMD in spine-BMD:-0.169, 95%CI:-0.476-0.138). Sensitivity analyses showed consistent results. CONCLUSION: Current publications indicate significant associations between bone fractures and ALD, independent of BMD or the presence of osteoporosis.

关键词： Alcoholic liver diseases Bone fractures Osteoporos

Effects of gamma-ray irradiation on free volume in polymers by positron annihilation lifetime spectroscopy

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Nuclear Science and Techniques 2014年第A01期25卷 31-35页

作者： Yongmin kim Jungki shin Junhyun KWON Department of Radiologieal Science Catholic University of Daegu Gyeongbuk 712-702 Republic of Korea Korea Research Institute of Standards and Science Daejeon 305-430 Republic of Korea Korea Atomic Energy Research Institute Daejeon 305-353 Republic of Korea

The positron annihilation lifetime (PAL) technique has been applied to study the effects of gamma-ray irradiation on polymer materials, such as ethylene propylene diene monomer (EPDM), nitrile butadiene rubber (NBR), and chloroprene rubber (CR), used in various industries. PAL measurements were performed with a conventional fast-fast coincidence system. Polymer materials were irradiated with 25 Gy/h in three conditions (50, 100, 500 Gy) and 5 kGy/h in six conditions (5, 50, 200, spo, 800, and 1 000 kGy) at room temperature with a (60)co gamma-ray source. Afterwards, the irradiated samples were measured by PAL spectroscopy. The delayed lifetime spectra of irradiated and unirradiated samples were decomposed into three lifetime components. The lifetime parameters indicate the free-volume size and concentration. The longest lifetime component represents the free volume size in polymer. Free volume and intensity were multiplied as a measure of relative fraction of free-volume hole. Cross-linking and degradation could occur when a polymer is irradiated. The free volumes of polymers were decreased accordingly. These results were verified through PAL measurement. From the Tao-Eldrup model, the mean radius and free volume fraction of CR, EPDM, and NBR were calculated. We certified the decrease of the fractional free volume. From these results, this study verified the feasibility of PA application on polymers.

关键词：正电子湮没寿命谱自由体积聚合物射线辐照 γ-射线照射高分子材料丁二烯橡胶伽玛

Hepatitis B viral load affects prognosis of hepatocellular carcinoma

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World Journal of Gastroenterology 2014年第34期20卷 12039-12044页

作者： Su Jong Yu yoon Jun kim Department of Internal Medicine and Liver Research Institute Seoul National University College of MedicineSeoul 110-744South Korea

Hepatocellular carcinoma(HCC)is a complex disease that is dually challenging to treat due to underlying chronic liver disease in addition to the cancer *** prognosis of patients with HCC is determined by intrahepatic tumor status and reserved hepatic *** B virus(HBV)is an established major risk factor of HCC development,and HBV viral load is being increasingly recognized as a prognostic factor in the presence of established *** HBV viral load may affect the prognosis of HBV-related HCC patients in several ***,it is associated with more frequent recurrence of HBV-related HCC after ***,it is associated with more occurrence and severity of potentially life-threatening HBV ***,it is associated with more worsened liver function,which limits the therapeutic options for HBV-related ***,directly or indirectly,can induce *** patients with a high HBV DNA level and subsequent active hepatitis,adhesion molecules expressed on the sinusoidal cells are up-regulated and may increase intrahepatic *** progression after treatment can lead to a poor prognosis by reducing number of normal functioning ***,high HBV viral load can affect the prognosis of patientswith HCC by frequent recurrence after treatment for HCC and deterioration of hepatic function associated with HCC *** meta-analysis showed that antiviral treatment reduces HCC recurrence and liver-related mortality after curative therapy of *** the strong relationship between high HBV DNA load and poor survival outcome of HCC patients due to cancer progression,it is expected that long-term antiviral therapy results in the sustained HBV suppression,control of inflammation,reduction in HCC progression,and eventually in improved overall survival.

关键词： Hepatitis B virus DNA Hepatocellular carcinoma Progression Prognosis

Sutureless contact lens-type amniotic membrane for persistent epithelial defects after infectious keratitis

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International Journal of Ophthalmology(English edition) 2022年第8期15卷 1404-1406页

作者： Jung Hye shin Young-Ho Jung Hyun Beom Song Mee Kum kim Chang Ho yoon Department of Ophthalmology Seoul National University Hospital101 Daehak-roJongno-guSeoul 03080Republic of Korea Department of Ophthalmology Seoul National University College of Medicine103 Daehak-roJongno-guSeoul 03080Republic of Korea Laboratory of Ocular Regenerative Medicine and Immunology Biomedical Research InstituteSeoul National University Hospital101 Daehak-roJongno-guSeoul 03080Republic of Korea Department of Medical Science Seoul National University College of Medicine103 Daehak-roJongno-guSeoul 03080Republic of Korea

Dear Editor,We are writing to present two case reports of persistent epithelial defect after infectious keratitis successfully treated with sutureless contact lens-type amniotic membrane(AM)*** keratitis is one of the leading causes of corneal *** disrupts the normal corneal healing process and induces inflammation,limbal cell dysfunction,and corneal surface irregularity,which can lead to corneal opacities or persistent epithelial defects(PEDs)[1].Untreated PED can cause corneal thinning,resulting in corneal perforation.

关键词： keratitis healing corneal