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AC Conductance Through a Vibrating Molecular Dot in Kondo Regime

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Communications in Theoretical Physics 2007年第12期48卷 1107-1114页

作者： Hyun-Chul Yong School of Physics Peking UniversityBeijing 100871China

In the present paper,by applying the Lang-Firsov canonical transformation and the so-called non-crossingapproximation technique,we investigate the joint effects of the electron-phonon interaction and an external alternatinggate voltage on the transport of a quantum dot system in the Kondo regime.We find that,while the satellite Kondoresonant peaks appear in both the averaged local density of states and the differential conductance,the main Kondopeak at the Fermi energy is greatly suppressed.These results confirm the previous ones derived by other methods,suchas the equation of motion solution.Furthermore,based on the picture of virtual transition between quasi-eigenstates inthe system,we also give a slightly different explanation on these phenomena.

关键词： quantum dot Kondo effect electron-phonon interaction AC conductance

End-of-life batteries management and material flow analysis in South Korea

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Frontiers of Environmental Science & Engineering 2018年第3期12卷 55-67页

作者： Hyunhee Kim yong-chul Jang Yeonjung Hwang Youngjae Ko Hyunmyeong Yun Department of Environmental Engineering Chungnam National University Daejeon 34134 South Korea Waste to Energy Research Division Environmental Resources Research Department National Institute of Environmental Research Incheon 22689 South Korea Daejeon Green Environment Center Daejeon 34134 South Korea

Consumers increasingly have worn-out batteries as electrical and electronic equipment with new technical developments are introduced into the market and quickly replace older models. As a result, large amounts of end-of-life （EOL） or waste batteries are generated. Such batteries may contain a variety of materials that includes valuable resources as well as toxic elements. Thus, the proper recycling and management of batteries is very important from the perspective of resource conservation and environmental effect. The collection and recycling of EOL batteries is relatively low in South Korea compared to other countries, although an extended producer responsibility （EPR） policy was adopted for battery recycling in 2003. In this study, the management and material flow of EOL batteries is presented to determine potential problems and quantitative flow, based on literature review, site visits to battery recycling facilities, and interviews with experts in the Korea Battery Recycling Association （KBRA）, manufacturers, and regulators in government. The results show that approximately 558 tons of manganese-alkaline batteries, the largest fraction among recycling target items, was disposed in landfills or incinerators in 2015, while approximately 2,000 tons of batteries were recovered at a recycling facility by simple sorting and crushing processes. By raising environmental awareness, more diverse and effective collection systems could be established for consumers to easily dispose of EOL batteries in many places. Producers, retailers and distributors in South Korea should also play an important role in the collection of EOL batteries from consumers. Lithium-ion batteries from many electronic devices must be included in the EPR system for resource recovery.

关键词： End-of-life battery Recycling Material flow analysis （MFA）Extended producer responsibility （EPR）Resource recovery

Current practices in cancer pain management in Asia:a survey of patients and physicians across 10 countries

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Current practices in cancer pain management in Asia:a survey...

Ligand-free monophasic CuPd alloys endow boosted reaction kinetics toward energy-efficient hydrogen fuel production paired with hydrazine oxidation

2016中国医师协会疼痛医师专业委员会年会

作者： yong-chul Kim Seoul National University Hospital

＜正＞In order to implement more effective policies for cancer pain management,a better understanding of current practices is needed.Physicians managing cancer pain and patients experiencing cancer pain were randomly ...

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Journal of Materials Science & Technology 2023年第12期143卷 20-29页

作者： Yujeong Jeong Shreyanka Shankar Naik Yiseul Yu Jayaraman Theerthagiri Seung Jun Lee Pau Loke Show Hyun chul Choi Myong yong Choi Department of Chemistry(BK21 FOUR) Research Institute of Natural SciencesGyeongsang National UniversityJinju 52828Republic of Korea Core-Facility Center for Photochemistry&Nanomaterials Gyeongsang National UniversityJinju 52828Republic of Korea Zhejiang Provincial Key Laboratory for Subtropical Water Environment and Marine Biological Resources Protection Wenzhou UniversityWenzhou 325035China Department of Chemical and Environmental Engineering Faculty of Science and EngineeringUniversity of Nottingham MalaysiaJalan Broga43500 SemenyihSelangor Darul EhsanMalaysia Department of Chemistry Chonnam National UniversityGwangju 61186Republic of Korea

Optimizing the structure and components is a prevalent strategy for increasing electrocatalytic energy-saving H 2 fuel production.One of the sustainable and efficient techniques is electrocatalytic water split-ting for H 2 generation,but it is still restricted by the kinetically sluggish OER.Due to the lower standard oxidation potential of−0.33 V,replacing the OER with anodic hydrazine oxidation reaction(HzOR)is an effective way to extensively reduce the use of electricity in water electrolysis.Through alloying,the semiconductor and adsorption characteristics of Cu,interlaced by Pd 2+solution on the Pd surface by pulsed laser ablation(PLA)in methanol,are selectively altered to maximize cathodic HER and anodic HzOR performance.The optimal Cu1Pd3/C ratio demonstrates outstanding HER performance with a low overpotential of 0.315 V at 10 mA cm^(−2),as well as an ultralow overpotential of 0.560 V for HzOR in 0.5 M N_(2) H_(4)/1.0 M KOH.Furthermore,the constructed HzOR-assisted electrolyzer cell with Cu1Pd3/C||Cu1Pd3/C as anode and cathode exhibits a cell voltage of 0.505 V at 10 mA cm^(−2) with exceptional en-durance over 5 h.The current study advances competent CuPd alloys as multifunctional electrocatalysts for H 2 fuel production using a HzOR-assisted energy-efficient electrolyzer.

关键词： PLA CuPd alloy Sonochemical process HzOR Hydrazine evolution reaction Hydrazine splitting Water splitting

Effects of mesenchymal stem cell on dopaminergic neurons,motor and memory functions in animal models of Parkinson's disease:a systematic review and meta-analysis

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Neural Regeneration Research 2024年第7期19卷 1584-1592页

作者： Jong Mi Park Masoud Rahmati Sang chul Lee Jae Il Shin yong Wook Kim Department and Research Institute of Rehabilitation Medicine Yonsei University College of MedicineSeoulSouth Korea Department of Physical Education and Sport Sciences Faculty of Literature and Human SciencesLorestan UniversityKhoramabadIran Department of Pediatrics Yonsei University College of MedicineSeoulSouth Korea

Parkinson’s disease is chara cterized by the loss of dopaminergic neurons in the substantia nigra pars com pacta,and although restoring striatal dopamine levels may improve symptoms,no treatment can cure or reve rse the disease itself.Stem cell therapy has a regenerative effect and is being actively studied as a candidate for the treatment of Parkinson’s disease.Mesenchymal stem cells are considered a promising option due to fewer ethical concerns,a lower risk of immune rejection,and a lower risk of teratogenicity.We performed a meta-analysis to evaluate the therapeutic effects of mesenchymal stem cells and their derivatives on motor function,memory,and preservation of dopamine rgic neurons in a Parkinson’s disease animal model.We searched bibliographic databases(PubMed/MEDLINE,Embase,CENTRAL,Scopus,and Web of Science)to identify articles and included only pee r-reviewed in vivo interve ntional animal studies published in any language through J une 28,2023.The study utilized the random-effect model to estimate the 95%confidence intervals(CI)of the standard mean differences(SMD)between the treatment and control groups.We use the systematic review center for laboratory animal expe rimentation’s risk of bias tool and the collaborative approach to meta-analysis and review of animal studies checklist for study quality assessment.A total of 33studies with data from 840 Parkinson’s disease model animals were included in the meta-analysis.Treatment with mesenchymal stem cells significantly improved motor function as assessed by the amphetamine-induced rotational test.Among the stem cell types,the bone marrow MSCs with neurotrophic factor group showed la rgest effect size(SMD[95%CI]=-6.21[-9.50 to-2.93],P=0.0001,I^(2)=0.0%).The stem cell treatment group had significantly more tyrosine hydroxylase positive dopamine rgic neurons in the striatum([95%CI]=1.04[0.59 to 1.49],P=0.0001,I^(2)=65.1%)and substantia nigra(SMD[95%CI]=1.38[0.89 to 1.87],P=0.0001,I^(2)=75.3%),indicating a protective effect on dopaminergic neurons.Subgro

关键词： animal animal experimentation mesenchymal stem cells models Parkinson’s disease stem cell transplantation

Coupled CUBIC Congestion Control for MPTCP in Broadband Networks

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Computer Systems Science & Engineering 2023年第4期45卷 99-115页

作者： Jae yong Lee Byung chul Kim Youngmi Kwon Kimoon Han Department of Information and Communications Engineering Chungnam National UniversityDaejeon34134Korea Agency for Defense Development Daejeon34186Korea

Recently,multipath transmission control protocol(MPTCP)was standardized so that data can be transmitted through multiple paths to utilize all available path bandwidths.However,when high-speed long-distance networks are included in MPTCP paths,the traffic transmission performance of MPTCP is severely deteriorated,especially in case the multiple paths’characteristics are heavily asymmetric.In order to alleviate this problem,we propose a“Coupled CUBIC congestion control”that adopts TCP CUBIC on a large bandwidth-delay product(BDP)path in a linked increase manner for maintaining fairness with an ordinary TCP traversing the same bottleneck path.To verify the performance excellence of the proposed algorithm,we implemented the Coupled CUBIC Congestion Control into Linux kernels by modifying the legacy MPTCP linked-increases algorithm(LIA)congestion control source code.We constructed asymmetric heterogeneous network testbeds mixed with large and small BDP paths and compared the performances of LIA and Coupled CUBIC by experiments.Experimental results show that the proposed Coupled CUBIC utilizes almost over 80%of the bandwidth resource in the high BDP path,while the LIA utilizes only less than 20%of the bandwidth for the same path.It was confirmed that the resource utilization and traffic transmission performance have been greatly improved by using the proposed Coupled CUBIC in high-speed multipath networks,as well as maintaining MPTCP fairness with competing single-path CUBIC or Reno TCP flows.

关键词： MPTCP congestion control Coupled CUBIC high BDP network

Enhanced photocatalytic degradation of lindane using metal–semiconductor Zn@ZnO and ZnO/Ag nanostructures

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Journal of Environmental Sciences 2018年第12期30卷 107-115页

作者： Hyeon Jin Jung Ravindranadh Koutavarapu Seulki Lee Ju Hyun Kim Hyun chul Choi Myong yong Choi Department of Chemistry (BK21+) and Research Institute of Natural Science Gyeongsang National University Department of Chemistry Chonnam National University

To achieve enhanced photocatalytic activity for the degradation of lindane, we prepared metal–semiconductor composite nanoparticles（NPs）. Zn@ZnO core–shell（CS） nanocomposites, calcined ZnO, and Ag-doped ZnO（ZnO/Ag） nanostructures were prepared using pulsed laser ablation in liquid, calcination, and photodeposition methods, respectively, without using surfactants or catalysts. The as-prepared catalysts were characterized by using X-ray diffraction（XRD）, field-emission scanning electron microscopy, high-resolution transmission electron microscopy, ultraviolet–visible（UV–vis） spectroscopy, and photoluminescence spectroscopy. In addition, elemental analysis was performed by energy dispersive X-ray spectroscopy. The obtained XRD and morphology results indicated good dispersion of Zn and Ag NPs on the surface of the ZnO nanostructures. Investigation of the photocatalytic degradation of lindane under UV–vis irradiation showed that Zn@ZnO CS nanocomposites exhibit higher photocatalytic activity than the other prepared samples. The maximum degradation rate of lindane was 99.5% in 40 min using Zn@ZnO CS nanocomposites. The radical trapping experiments verified that the hydroxyl radical（·OH） was the main reactive species for the degradation of lindane.

关键词： Zn@ZnO ZnO/Ag Lindane Pulsed laser ablation in liquid Photocatalysis

Voluntary Disclosure and the Type of Product Market Competition： Capacity vs. Price

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Journal of Modern Accounting and Auditing 2013年第4期9卷 505-526页

作者： yong-chul Shin University of Massachusetts Boston Boston USA

This paper investigates empirically the effect of different types of product market competition on levels of voluntary disclosure of proprietary information in financial markets. The author proposes that there are two types of strategic interaction settings relevant to disclosure: capacity competition and price competition. Capacity competition drives firms to disclose more information to attain financial market valuation-related benefits, while price competition drives them to disclose less to protect long-term product market advantages. The author finds that the type of product market competition affects the level of voluntary disclosure over and above the firm’s external financing needs documented in the previous literature. That is, firms engaged in capacity competition disclose relatively more information than those in price competition. Further analysis shows that capacity competition firms disclose more information than no-strategic-interaction benchmark firms but that price competition firms do not disclose less information than the benchmark firms.

关键词：市场竞争能力价格竞争信息披露产品类型金融市场市场竞争力市场优势

Preparation and characterization of spray-dried valsartan-loaded Eudragit~? EPO solid dispersion microparticles

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Asian Journal of Pharmaceutical Sciences 2016年第6期11卷 744-750页

作者： Roshan Pradhan Sung Yub Kim chul Soon yong Jong Oh Kim College of Pharmacy Yeungnam University

The purpose of this study was to develop the immediate release stomach-specific spraydried formulation of valsartan(VAL) using Eudragit?E PO(EPO) as the carrier for enhancing dissolution rate in a gastric environment. Enhanced solubility and dissolution in gastric pH was achieved by formulating the solid dispersion using a spray drying technique. Different combinations of drug–polymer–surfactant were dissolved in 10% ethanol solution and spraydried in order to obtain solid dispersion microparticles. Use of the VAL–EPO solid dispersion microparticles resulted in significant improvement of the dissolution rate of the drug at pH 1.2 and pH 4.0, compared to the free drug powder and the commercial product. A hard gelatin capsule was filled with the VAL–EPO solid dispersion powder prior to the dissolution test.The increased dissolution of VAL from solid dispersion microparticles in gastric pH was attributed to the effect of EPO and most importantly the transformation of crystalline drugs to amorphous solid dispersion powder, which was clearly shown by scanning electron microscopy(SEM), differential scanning calorimetry(DSC), and powder X-ray diffraction(PXRD) studies. Thus, VAL, a potential antihypertensive drug in the form of a solid dispersion microparticulate powder, can be effectively delivered in the immediate release dosage form for stomach-specific drug delivery.

关键词： Valsartan Eudragit E PO Solubility Solid dispersion Spray-drying