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Yolk-shell-structured （***.s）9S8 solid-solution powders：Synthesis and application as anode materials for Na-ionbatteries

第11届国际电机与系统学术会议

作者： Kyung-Pyo Yi Jong-Seok Rho hyun-kyo jung School of Electrical Engineering and Computer Science Seoul National UniversitySeoul151-744Korea

＜正＞This paper presents the analysis method for a linear ultrasonic motor using radial and nonaxisymmetric vibration modes of an annular *** displacement of the stator is analyzed by 3D finite element method,and the contact between the stator and the mover is analyzed by analytic *** analysis results of the model with stator radius of 10.00mm and thickness of 1.00mm is compared with experimental results to verify the analysis method.

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Nano Research 2017年第9期10卷 3178-3188页

作者： jung hyun Kim Yun Chan Kang Department of Materials Science and Engineering Korea University Anam-Dong Seongbuk-Gu Seou1136-713 Republic of Korea

Multicomponent metal sulfide materials with a yolk–shell structure and a single phase were studied for the first time as anode materials for sodium-ion batteries. Yolk–shell-structured Fe–Ni–O powders with a molar ratio of iron and nickel components of 1/1 were prepared via one-pot spray pyrolysis. The prepared Fe–Ni–O powders were transformed into yolk–shell-structured (Fe0.5Ni0.5)9S8 solid-solution powders via a sulfidation process. The initial discharge and charge capacities of the (Fe0.5Ni0.5)9S8 powders at a current density of 1 A·g−1 were 601 and 504 mA·h·g−1, respectively. The discharge capacities of the (Fe0.5Ni0.5)9S8 powders for the 2nd and 100th cycle were 530 and 527 mA·h·g−1, respectively, and their corresponding capacity retention measured from the 2nd cycle was 99%. The (Fe0.5Ni0.5)9S8 powders had high initial discharge and charge capacities at a low current density of 0.1 A·g−1, and the reversible discharge capacity decreased slightly from 568 to 465 mA·h·g−1 as the current density increased from 0.1 to 5.0 A·g−1. The synergetic effect of the novel yolk–shell structure and the multicomponent sulfide composition of the (Fe0.5Ni0.5)9S8 powders resulted in excellent sodium-ion storage performance.

关键词： metal sulfide multicomponent sulfide yolk–shell sodium-ion batteries spray pyrolysis

Effects of Polymeric Stabilizers on the Synthesis of Gold Nanoparticles

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Journal of Materials Science & Technology 2014年第2期30卷 107-111页

作者： Eun jung Kim Jeong hyun Yeum Jin hyun Choi Department of Advanced Organic Materials Science and Engineering Kyungpook National University Department of Bio-fibers and materials Science Kyungpook National University

Gold nanoparticles （AuNPs） stabilized with sodium alginate （SA）, glycol chitosan （GC）, polyvinyl alcohol （PVA）, and polyethyleneimine （PEI） were synthesized in aqueous solutions at room temperature. Different sizes and size distributions of AuNPs were obtained according to the polymeric stabilizers. The mean particle diameters of AuNPs synthesized with GC and PVA as stabilizers were about 5.1 and 5.3 nm, respectively, while those of AuNPs stabilized with SA and PEI were 8.4 and 10.8 nm, respectively. When SA was used, relatively large particles aggregated to form large clusters. In the case of GC, a number of small particles built up large clusters. When PVA was used, the size and the number of nanoperticles were estimated small with a low weight content of Au. For this reason, the PVA-stabilized AuNPs formed clusters with a small hydrodynamic size. The AuNPs synthesized in the aqueous solution of PEI without a reducing agent, sodium borohydride, were uniform in size and formed the smallest nanoclusters （67.4 nm）. In this case, the highest Au content was obtained. Sufficiently grown nanoparticles with a high Au content and a limited hydrodynamic size are considered to be suitable for a variety of applications.

关键词： Gold nanoparticles Sodium alginate Glycol chitosan Polyvinyl alcohol Polyethyleneimine

Anti-obesity Effects of Ginsenosides in High-Fat Diet-Fed Rats

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Chinese Journal of Integrative Medicine 2019年第12期25卷 895-901页

作者： hyun-jung Park Ji hyun Kim Insop Shim Department of Physiology College of MedicineKyung Hee UniversitySeoul(130-701)Republic of Korea Department of Food Science&Biotechnology College of Science and EngineeringSuwon-si(16227)Republic of Korea

Objective: To examine the anti-obesity effects of ginsenosides in Korea Red Ginseng(KRG, Panax ginseng) in rats fed with a high-fat diet(HFD). Methods: Twenty-five 4-week-old obesity rats after receiving an HFD for 5 weeks;subsequently, they were additionally treated with ginsenosides Rb1, Rd, Rg1, or Re(10 mg/kg, intraperitoneal injection) for a further 3 weeks(n=5 in each group). The control rats were fed a normal diet. The food consumption, body weight, locomotor activity, serum lipids, adipose tissues, nitric oxide(NO) expression, leptin, neuropeptide Y(NPY), cholecystokinin(CCK) in the brains were measured. Results: In the HFD-fed rats, body weight, body fat mass, serum levels of leptin and NO were significantly higher than in the control rats(P<0.05 or P<0.01). However, the treatment of Rd, Re, and Rb1 markedly decreased body fat mass and body weight(P<0.05). The serum level of leptin and NO in ginsenoside-treated rats were markedly lower than the control group(P<0.01). The expression of NPY and CCK in the hypothalamic nuclei showed insignificant difference among groups. However, the expression of NPY immunoreactive neurons in the hypothalamus was significantly reduced in the Rb1-treated group(P<0.05). Conclusion: PD-type ginsenoside Rb1 from the crude saponins of KRG may be a useful compound for the treatment of obesity and related disorders through the modulation of peripheral and central appetite-regulating signals.

关键词： Panax ginseng ginsenosides hypothalamus obesity

Adverse effects of early-life stress:focus on the rodent neuroendocrine system

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Neural Regeneration Research 2024年第2期19卷 336-341页

作者： Seung hyun Lee Eui-Man jung Department of Molecular Biology College of Natural SciencesPusan National UniversityBusanRepublic of Korea

Early-life stress is associated with a high prevalence of mental illnesses such as post-traumatic stress disorders,attention-deficit/hyperactivity disorder,schizophrenia,and anxiety or depressive behavior,which constitute major public health *** the early stages of brain development after birth,events such as synaptogenesis,neuron maturation,and glial differentiation occur in a highly orchestrated manner,and external stress can cause adverse long-term effects throughout *** body utilizes multifaceted mechanisms,including neuroendocrine and neurotransmitter signaling pathways,to appropriately process external *** individuals first exposed to early-life stress deploy neurogenesis as a stress-defense mechanism;however,in adulthood,early-life stress induces apoptosis of mature neurons,activation of immune responses,and reduction of neurotrophic factors,leading to anxiety,depression,and cognitive and memory *** process involves the hypothalamus-pituitary-adrenal axis and neurotransmitters secreted by the central nervous system,including norepinephrine,dopamine,and *** rodent early-life stress model is generally used to experimentally assess the effects of stress during *** paper reviews the use of the early-life stress model and stress response mechanisms of the body and discusses the experimental results regarding how early-life stress mediates stress-related pathways at a high vulnerability of psychiatric disorder in adulthood.

关键词： early-life stress hypothalamic-pituitary-adrenergic axis maternal separation mental illness neurodevelopmental disorder neuroendocrine system neurotransmitter

Micro RNAs in liver fibrosis: Focusing on the interaction with hedgehog signaling

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World Journal of Gastroenterology 2016年第29期22卷 6652-6662页

作者： Jeongeun hyun Youngmi jung Department of Biological Sciences College of Natural Science Pusan National University

Liver fibrosis is a repair process in response to damage in the liver; however, severe and chronic injury promotes the accumulation of fibrous matrix, destroying the normal functions and architecture of liver. Hepatic stellate cells(HSCs) are quiescent in normal livers, but in damaged livers, they transdifferentiate into myofibroblastic HSCs, which produce extracellular matrix proteins. Hedgehog(Hh) signaling orchestrates tissue reconstruction in damaged livers and contributes to liver fibrogenesis by regulating HSC activation. Micro RNAs(mi RNAs), endogenous small non-coding RNAs interfering with RNA post-transcriptionally, regulate various cellular processes in healthy organisms. The dysregulation of mi RNAs is closely associated with diseases, including liver diseases. Thus, mi RNAs are good targets in the diagnosis and treatment of various diseases, including liver fibrosis; however, the regulatory mechanisms of mi RNAs that interact with Hh signaling in liver fibrosis remain unclear. We review growing evidence showing the association of mi RNAs with Hh signaling. Recent studies suggest that Hh-regulating mi RNAs induce inactivation of HSCs, leading to decreased hepatic fibrosis. Although mi RNAdelivery systems and further knowledge of interacting mi RNAs with Hh signaling need to be improved for the clinical usage of mi RNAs, recent findings indicate that the mi RNAs regulating Hh signaling are promising therapeutic agents for treating liver fibrosis.

关键词： Micro RNA Liver fibrosis Hedgehog Hepatic stellate cell

Chemical surface tuning of zinc metal anode toward stable,dendrite-less aqueous zinc-ion batteries

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Journal of Energy Chemistry 2023年第11期86卷 1-8,I0001页

作者： Pranav Kulkarni Sun-Sik Kim hyun Young jung Department of Energy Engineering Gyeongsang National UniversityJinju-siGyeongnam 52725South Korea Department of Energy System Engineering Gyeongsang National UniversityJinju-siGyeongnam 52725South Korea

The commercialization of Zn batteries is confronted with urgent challenges in the metal anode,such as dendrite formation,capacity loss,and cracking or ***,surface interfacial engineering of the Zn anode is introduced for achieving safety and dendritic-free cycling for high-performance aqueous Zn batteries through a simple but highly effective chemical etching-substitution *** chemical modification induces a rough peak-valley surface with a thin fluorine-rich interfacial layer on the Zn anode surface,which regulates the growth orientation via guiding uniform Zn plating/stripping,significantly enhances accessibility to aqueous electrolytes and improves wettability by reducing surface *** a result,such a synergetic surface effect enables uniform Zn plating/stripping with low polarization of 29 m V at a current density of 0.5 m A cm^(-2) with stable cyclic performance up to 1000 ***,a full cell composed of a fluorine-substituted Zn anode coupled with aβ-MnO_(2)or Ba-V_(6)O_(13)cathode demonstrates improved capacity retention to 1000 cycles compared to the pristine-Zn *** proposed valley deposition model provides the practical direction of surface-modified interfacial chemistries for improving the electrochemical properties of multivalent metal anodes via surface tuning.

关键词： Dendrite free Peak-Valley surface Zinc-ion batteries Surface modification Fluorinated interface

Effects of compressive stress on the nonlinear electromechanical behavior of ferroelectric ceramics

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Science China(Technological Sciences) 2006年第1期49卷 29-37页

作者： LEE jung-Ju KIM hyun Cheol Department of Mechanical Engineering KAIST Taejon 305-701 Korea

The effects of compressive stress parallel and perpendicular to the polar axis of PZT ceramics on the nonlinear electromechanical behavior of the materials has been experimentally studied. A domain-switching model that divides each 180° switching to two successive 90° switching is proposed to explain these effects. In the case of stress parallel to the polar axis, domain switching in the ceramics is approximately axisymmetric and can be simulated by an analytical model. While in the case of stress perpendicular to the polar axis, domain switching is three-dimensional and cannot be simplified. The simulated re-sults that match the experiments well show the validity of the proposed domain-switching model.

关键词： ferroelectric ceramics, domain switching, electromechanical, PZT.

Preparation and characterization of Li_(4)Ti_(5)O_(12) synthesized using hydrogen titanate nanowire for hybrid super capacitor

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Journal of Advanced Ceramics 2013年第3期2卷 285-290页

作者： Jong hyun KIM jung Rag YOON R&D Center Samwha Capacitor Co.Ltd.YonginGyeonggi 449-884R.O.Korea

The electrical characteristics of hybrid super capacitor were evaluated by synthesizing LTO(Li_(4)Ti_(5)O_(12))using TiO_(2) having a hydrogen titanate nanowire *** of the hydrogen titanate nanowire was implemented by using TiO_(2) having size of 60 nm and NaOH,and performing synthesis at 70℃for 6 h with a sonochemical *** compound was synthesized at 150℃for 36 h and at 180℃for 36 h respectively by using the hydrogen titanate nanowire and LiOH·H2O as starting materials with a hydrothermal *** final LTO compound was synthesized at 700℃for 6 h using a solid-state *** a result of manufacturing the hybrid super capacitor using LTO synthesized at 180℃for 36 h with the hydrothermal method,a capacity of 198 mA·h/g has been achieved compared to a theoretical capacity of 172 mA·h/g of existing LTO,and thus,the capacity has been increased by about 13%.Further,such excellent cycle performance has ensured its possibility as a high-capacity capacitor.

关键词： LTO(Li4Ti5O12) lithium titanate oxide hydrogen titanate nanowire hybrid super capacitor