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

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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

Effect of the protection layer formed by cross-linked gelatin on the stability and performance of glucose and oxygen fuel cells

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Journal of Energy Chemistry 2021年第10期30卷 155-162,I0005页

作者： Kyuhwan hyun Joonyoung Lee Suhyeon kang Yongchai Kwon Graduate School of Energy and Environment Seoul National University of Science and Technology232 Gongneung-roNowon-guSeoul 01811Republic of Korea Department of Chemical and Biomolecular Engineering Seoul National University of Science and Technology232 Gongneung-roNowon-guSeoul 01811Republic of Korea

A glucose oxidation catalyst comprising carbon nanotube,tetrathiafulvalene(TTF),gelatin,glutaraldehyde(GA)and glucose oxidase(GOx)(CNT/[TTF-GOx]/Gelatin+GA)is suggested to enhance the reactivity of glucose oxidation reaction(GOR),and the performance and stability of enzymatic biofuel cells(EBCs)using this *** this catalyst,TTF is used as mediator to transfer electron effectively,while GA is crosslinked to gelatin to form non-soluble *** structure prevents the dissolution of gelatin from aqueous electrolyte and reduces the leaching-out of GOx and TTF *** confirm the crosslinking effect of GA and gelatin,Fourier-transform infrared spectroscopy(FT-IR)and electrochemical evaluations are *** to FT-IR analysis,it was observed that the amide I peak shifted after *** is evidence showing the appropriate network formation and the reactivity of CNT/[TTFGOx]/Gelatin+GA is well preserved even after multiple potential *** addition,its GOx activity is regularly monitored for one month and the measurements prove that the structure prevents the leaching out of GOx *** on that,EBC using the anodic catalyst shows excellent performances,such as open circuit voltage of 0.75 V and maximum power density of 184μW/cm^(2).

关键词： Enzymatic biofuel cell Tetrathiafulvalene Crosslinking of glutaraldehyde and gelatin Hemi-acetal bond group

Local dose-dense chemotherapy for triple-negative breast cancer via minimally invasive implantation of 3D printed devices

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Asian Journal of Pharmaceutical Sciences 2024年第1期19卷 69-85页

作者： Noehyun Myung hyun-Wook kang Department of Biomedical Engineering Ulsan National Institute of Science and Technology(UNIST)Ulju-gun 44919South Korea

Dose-dense chemotherapy is the preferred first-line therapy for triple-negative breast cancer(TNBC),a highly aggressive disease with a poor *** treatment uses the same drug doses as conventional chemotherapy but with shorter dosing intervals,allowing for promising clinical outcomes with intensive ***,the frequent systemic administration used for this treatment results in systemic toxicity and low patient compliance,limiting therapeutic efficacy and clinical ***,we report local dose-dense chemotherapy to treat TNBC by implanting 3D printed devices with timeprogrammed pulsatile release *** implantable device can control the time between drug releases based on its internal microstructure design,which can be used to control dose *** device is made of biodegradable materials for clinical convenience and designed for minimally invasive implantation via a *** density variation of local chemotherapy using programmable release enhances anti-cancer effects in vitro and in *** the same dose density conditions,device-based chemotherapy shows a higher anticancer effect and less toxic response than intratumoral *** demonstrate local chemotherapy utilizing the implantable device that simulates the drug dose,number of releases,and treatment duration of the dose-dense AC(doxorubicin and cyclophosphamide)regimen preferred for TNBC *** density modulation inhibits tumor growth,metastasis,and the expression of drug resistance-related proteins,including p-glycoprotein and breast cancer resistance *** the best of our knowledge,local dose-dense chemotherapy has not been reported,and our strategy can be expected to be utilized as a novel alternative to conventional therapies and improve anti-cancer efficiency.

关键词： Dose-dense chemotherapy Triple-negative breast cancer 3D printing Pulsatile release Local drug delivery systems

Prediction of Melt Pool Dimension and Residual Stress Evolution with Thermodynamically-Consistent Phase Field and Consolidation Models during Re-Melting Process of SLM

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Computers, Materials & Continua 2021年第1期66卷 87-112页

作者： kang-hyun Lee Gun Jin Yun Department of Aerospace Engineering Seoul National UniversitySeoul08826South Korea Institute of Advanced Aerospace Technology Seoul National UniversitySeoul08826South Korea

Re-melting process has been utilized to mitigate the residual stress level in the selective laser melting(SLM)process in recent ***,the complex consolidation mechanism of powder and the different material behavior after the first laser melting hinder the direct implementation of the re-melting *** this work,the effects of re-melting on the temperature and residual stress evolution in the SLM process are investigated using a thermo-mechanically coupled finite element *** degree of consolidation is incorporated in the energy balance equation based on the thermodynamically-consistent phase-field *** drastic change of material properties due to the variation of temperature and material state is also *** the proposed simulation framework,the single-track scanning is simulated first to predict the melt pool dimension and validate the proposed model with the existing experimental *** obtained thermal histories reveal that the highest cooling rate is observed at the end of the local solidification time which acts as an important indicator for the alleviation of temperature ***,the scanning of a whole single layer that consists of multiple tracks is simulated to observe the stress evolution with several re-melting *** the full melting of powder material in the first scanning process,the increase of residual stress level is observed with one remelting ***,the predicted stress level with the re-melting process shows the variation trend attributable to the accumulated heat in the *** numerical issues and the detailed implementation process are also introduced in this paper.

关键词： Selective laser melting thermo-mechanical analysis Ti-6Al-4V additive manufacturing re-melting residual stress

Three-dimensional spongy nanographene-functionalized silicon anodes for lithium ion batteries with superior cycling stability

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Nano Research 2018年第1期11卷 233-245页

作者： Chunfei Zhang Tong-hyun kang Jong-Sung Yu Department of Energy Systems Engineering DGIST Daegu 42988 Republic of Korea

An innovative spongy nanographene （SG） shell for a silicon substrate was prepared by low-temperature chemical vapor deposition on a hierarchical nickel nanotemplate. The SG-functionalized silicon （Si@SG） composite shows outstanding properties, which may be helpful to overcome issues affecting current silicon anodes used in lithium ion batteries such as poor conductivity, large volume expansion and high mass transfer resistance. The hierarchical nanographene shell exhibits elastic, sponge-like features that allow it to self-adaptively change its volume to accommodate the volume expansion of silicon. In addition, the porous, spongy framework containing randomly stacked graphene nanosheets presents low diffusion barriers and provides sufficiently free and short-haul channel segments to allow the fast migration of Li and electrolyte ions. The unique properties of the present silicon anode result in excellent electrochemical performances in terms of long-term cycling stability （95% capacity retention after 510 cycles）, rate performance, and cycling behavior for high mass loadings at different current densities.

关键词： spongy nanographene core-shell silicon lithium ion battery three-dimensionalstructure

Mitigation of micro vibration by viscous dampers

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Earthquake Engineering and Engineering Vibration 2009年第4期8卷 569-582页

作者： Tzu-kang Lin Chu-Chieh jay Lin Jenn-Shin Hwang Center for Research on Earthquake Engineering(NCREE) Shin-Hai Rd.Chinese Taipei Department of Construction Engineering Taiwan University of Science and Technology

This study proposes a micro vibration mitigation system using viscous dampers to solve the problem of vibration in a high-tech building. Due to the operating frequency of the air conditioners and fundamental mode of the floors, a resonant phenomenon is occasionally experienced at the upper levels of the structure. Several strategies were considered, and viscous dampers combined with a suspension system were chosen to mitigate this annoying situation. A theoretical analysis was first executed to determine the optimal design value of the damper and the suspension spring. An efficient reduction in floor velocity of approximately 50 % was achieved by the proposed system. Practical verifications including a performance test of the micro-vibration-oriented dampers, the pragmatic application result, and a comparison in one-third octave spectrum was then carried out. The performance of the system was demonstrated by the data measured. It alleviated more trembling than was numerically expected. The energy absorbed by the viscous dampers is illustrated by the hysteresis loops and the one-third octave spectrum. It is found that with the proposed system, the vibration can be effectively captured by the viscous damper and converted to lower frequency-content tremors. The success of this project greatly supports the proposed standard two-stage analysis procedure for mitigating micro-vibration problems in practice. This research extends the use of viscous dampers to a new field.

关键词： viscous damper: micro vibration: structural control

MOF‑Derived CoSe2@N‑Doped Carbon Matrix Confined in Hollow Mesoporous Carbon Nanospheres as High‑Performance Anodes for Potassium‑Ion Batteries

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Nano-Micro Letters 2021年第1期13卷 123-137页

作者： Su hyun Yang Seung‑Keun Park Yun Chan kang Department of Materials Science and Engineering Korea UniversityAnam‑DongSeongbuk‑GuSeoul 136‑713Republic of Korea Department of Chemical Engineering Kongju National University1223‑24 Cheonan‑daeroSeobuk‑guCheonan 31080Republic of Korea

In this work,a novel vacuum-assisted strategy is proposed to homogenously form Metal-organic frameworks within hollow mesoporous carbon nanospheres(HMCSs)via a solid-state *** method is applied to synthesize an ultrafine CoSe2 nanocrystal@N-doped carbon matrix confined within HMCSs(denoted as CoSe2@NC/HMCS)for use as advanced anodes in highperformance potassium-ion batteries(KIBs).The approach involves a solvent-free thermal treatment to form a Co-based zeolitic imidazolate framework(ZIF-67)within the HMCS templates under vacuum conditions and the subsequent *** treatment under vacuum facilitates the infiltration of the cobalt precursor and organic linker into the HMCS and simultaneously transforms them into stable ZIF-67 particles without any *** the subsequent selenization process,the“dual confinement system”,composed of both the N-doped carbon matrix derived from the organic linker and the small-sized pores of HMCS,can effectively suppress the overgrowth of CoSe2 ***,the resulting uniquely structured composite exhibits a stable cycling performance(442 mAh g^−1 at 0.1 A g^−1 after 120 cycles)and excellent rate capability(263 mAh g^−1 at 2.0 A g^−1)as the anode material for KIBs.

关键词： Metal-organic frameworks Hollow mesoporous carbon nanospheres Potassium-ion batteries Cobalt selenides Electrode materials

Laparoscopic surgery for gastric cancer:Current status and future direction

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Chinese Journal of Cancer Research 2021年第2期33卷 133-141页

作者： So hyun kang hyung-Ho Kim Department of Surgery Seoul National University Bundang HospitalSeongnam 13620Republic of Korea Department of Surgery Seoul National University College of MedicineSeoul 03080Republic of Korea

Gastric cancer is still a major cause of death *** laparoscopic gastrectomy(LG)has gained evidence as a standard treatment for early gastric cancer in the distal stomach,there are still concerns regarding its application for gastric cancer in the upper stomach and advanced gastric ***,LG has shown to have faster recovery,shorter hospital stay,less pain,and less blood loss in many retrospective and prospective *** application of LG has now extended from conventional radical gastrectomy to novel approaches such as function-preserving gastrectomy and sentinel-node navigated *** on the use of laparoscopy in treatment for stage IV gastric cancer are rare,but show that there may be some roles of LG in selected *** the development of new laparoscopic tools that augment human ability,the future of LG should move on from proving non-inferiority to demonstrating superiority compared to the traditional open gastrectomy.

关键词： Laparoscopy stomach neoplasm minimally invasive surgical procedures

Counter-balancing effects of Si on C partitioning and stacking fault energy of austenite in 10Mn quenching and partitioning steel

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Journal of Materials Science & Technology 2022年第3期98卷 248-257页

作者： Dong Hwi Kim Jee-hyun kang Hojun Gwon Joo hyun Ryu Sung-Joon Kim Graduate Institute for Ferrous Technology Pohang University of Science and TechnologyPohang 37673Republic of Korea School of Materials Science and Engineering Institute of Materials TechnologyYeungnam UniversityGyeongsan 38541Republic of Korea POSCO Technical Research Laboratories POSCOGwangyang 57807Republic of Korea

Silicon is an essential alloying element in quenching and partitioning(Q&P)steels,because it is known to suppress carbide precipitation during partitioning step and promote carbon partitioning to stabilize *** 2 wt%Si was added to 10Mn-2Al-0.2C steel,the size and fraction of the carbides formed during partitioning became smaller than in the Si-free ***,the suppression of carbide formation promoted C partitioning into austenite as ***,austenite stability was always lower with Si under the equivalent partitioning condition because Si effectively decreased the stacking fault energy of *** partitioning progressed,the both yield and tensile strengths of the Si-added steel exceeded that of the Si-free steel with the similar ductility *** was because Si was an effective solid solution strengthener,and the austenite in the Si-added steel exhibited the appropriate stability to gradually transform into martensite throughout the *** resulting strengthening effect compensated for the softening caused by martensite ***,strain hardening rate decreased continuously throughout deformation,which resulted in high tensile strength and ductility.

关键词： Steels Q&P steel Silicon Austenite stability Tensile deformation Stacking fault energy Medium Mn steel