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Domain-engineered BiFeO3 thin-film photoanodes for highly enhanced ferroelectric solar water splitting

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Nano Research 2018年第2期11卷 642-655页

作者： Jaesun Song Taemin Ludvic kim Jongmin Lee Sam Yeon Cho Jaeseong Cha Sang Yun Jeong Hyunji An Wan Sik kim Yen-sook Jung Jiyoon Park Gun young Jung Dong-Yu kim Ji young Jo Sang Don Bu Ho Won Jang Sanghan Lee School of Materials Science and Engineering Gwangju Institute of Science and Technology (GIST) Gwangju Republic of Korea Department of Materials Science and Engineering Research Institute of Advanced Materials Seoul National University Seoul Republic of Korea Department of Physics Chonbuk National University Jeonju Republic of Korea

In photoelectrochemical （PEC） water splitting, charge separation and collection by the electric field in the photoactive material are the most important factors for improved conversion efficiency. Hence, ferroelectric oxides, in which electrons are the majority carriers, are considered promising photoanode materials because their high built-in potential, provided by their spontaneous polarization, can signifi＇canfly enhance the separation and drift of photogenerated carriers. In this regard, the PEC properties of BiFeO3 thin-film photoanodes with different crystallographic orientations and consequent ferroelectric domain structures are investigated. As the crystallographic orientation changes from （001）pc via （ll0）pc to （lll）p~, the ferroelastic domains in epitaxial BiFeO3 thin films become mono-variant and the spontaneous polarization levels increase to 110 btC/cm2. Consequent136 the photocurrent density at 0 V vs. Ag/AgC1 increases approximately 5.3-fold and the onset potential decreases by 0.180 V in the downward polarization state. It is further demonstrated that ferroelectric switching in the （lll）pc BiFeO3 thin-film photoanode leads to an approximate change of 8,000% in the photocurrent density and a 0.330 V shift in the onset potential. This study strongly suggests that domain-engineered ferroelectric materials can be used as effective charge separation and collection layers for efficient solar water-splitting photoanodes.

关键词： BiFeO3 ferroelectric photoelectrochemical domain orientation pulsed laser deposition

Melatonin modulates adiponectin expression on murine colitis with sleep deprivation

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World Journal of Gastroenterology 2016年第33期22卷 7559-7568页

作者： Tae Kyun kim young sook Park Haing-Woon Baik Jin Hyun Jun Eun Kyung kim Jae Woong Sull Ho Joong Sung Jin Woo Choi sook Hee Chung Myung Chan Gye Ju Yeon Lim Jun Bong kim Seong Hwan kim Department of Gastroenterology Eulji University School of MedicineEulji Hospital Department of Biochemistry and Molecular Biology Eulji University School of Medicine Departemnt of Biomedical Laboratory Science Graduate School of Health ScienceEulji University Departemnt of Senior Healthcare BK21 plus ProgramGraduate SchoolEulji University Department of Pathology Eulji University School of Medicine Department of Gastroenterology Ajou University School of Medicine Department of Life Science and Institute of Natural Sciences Hanyang University

AIM To determine adiponectin expression in colonic tissue of murine colitis and systemic cytokine expression after melatonin treatments and sleep *** The following five groups of C57BL/6 mice were used in this study:(1) group Ⅰ,control;(2) group Ⅱ,2% DSS induced colitis for 7 d;(3) group Ⅲ,2% DSS induced colitis and melatonin treatment;(4) group Ⅳ,2% DSS induced colitis with sleep deprivation(SD) using specially designed and modified multiple platform water baths; and(5) group V,2% DSS induced colitis with SD and melatonin treatment. Melatonin(10 mg/kg) or saline was intraperitoneally injected daily to mice for 4 d. The body weight was monitored daily. The degree of colitis was evaluated histologically after sacrificing the mice. Immunohistochemical staining and Western blot analysis was performed using anti-adiponectin antibody. After sampling by intracardiac punctures,levels of serum cytokines were measured by ELISA. RESULTS Sleep deprivation in water bath exacerbated DSS induced colitis and worsened weight loss. Melatonin injection not only alleviated the severity of mucosal injury,but also helped survival during stressful condition. The expression level of adiponectin in mucosa was decreased in colitis,with the lowest level observed in colitis combined with sleep deprivation. Melatonin injection significantly(P < 0.05) recovered the expression of adiponectin. The expression levels of IL-6 and IL-17 were increased in the serum of mice with DSS colitis but decreased after melatonin injection. CONCLUSION This study suggested that melatonin modulated adiponectin expression in colonic tissue and melatonin and adiponectin synergistically potentiated antiinflammatory effects on colitis with sleep deprivation.

关键词： Colitis Melatonin Adiponectin Sleep deprivation

Cutoff characteristics of dielectric-filled circular holes embedded in dispersive plasmonic medium

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Chinese Optics Letters 2009年第10期7卷 904-908页

作者： Ki young kim Department of Physics National Cheng Kung University

The cutoff characteristics of dielectric-filled circular holes embedded in a dispersive plasmonic medium are investigated. Since two distinctive operating modes, surface plasmon polariton and circular waveguide modes, can exist in the slow and fast wave regions, respectively, the cutoff characteristics for each are separately investigated for linear and radial polarizations of the guided fields. As a result, the cutoff wavelengths for the linear and radial polarizations with very small subwavelength hole radii are found to be limited by the plasma resonance wavelength and plasma wavelength, which in turn are dependent and independent, respectively, of the dielectric constant of the dielectric filler material.

关键词： Circular waveguides Polarization Surface plasmon resonance

Robust fault detection of piecewise affine ARX systems

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Journal of Control and Decision 2020年第3期7卷 276-285页

作者： young-Man kim School of Engineering Liberty University1971 University Blvd.LynchburgVAUSA

In this paper,l1 regularisation-based robust fault detection technique for PWARX(PieceWise affine Auto Regressive eXogenous)systems is *** problem is formulated in convex optimisation form using l1 regularisation hence,global solution can be *** regularisation constant plays a key role for finding the number of *** MSE(mean square error)value between actual system and its model under no fault is used as a threshold for tracking dynamics change and detecting *** simplicity of turning only one parameter(regularisation constant)outstands this approach from *** proposed algorithm also shows the capability of separating the dynamics change from additive fault under *** illustration concludes this proposal by demonstrating its effectiveness.

关键词： Piecewise affine ARX fault detection regularisation convex optimisation sparsity

Effect of carrier gas species on the microstructure and compressive deformation behaviors of ultra-strong pure copper manufactured by cold spray additive manufacturing

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Journal of Materials Science & Technology 2022年第2期97卷 264-271页

作者： young-Kyun kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea

Cold spray(CS)which has recently become a promising additive manufacturing(AM)technology,was used to fabricate ultra-strong pure *** addition,the effects of carrier gas species on the microstructural characteristics,mechanical properties and deformation mechanisms were systemically *** CSAM copper manufactured with N_(2) carrier gas reveals a heterogeneous bimodal microstructure consisting of ultra-fine grains at the particle interface and relatively coarse grains in inner *** He carrier gas,a homogeneous grain structure consisting of ultra-fine grains in most areas was *** tests showed that N_(2) and He carrier gasses enabled ultra-high yield strengths of 340 and415 MPa,*** values are comparable to severely plastic deformed copper,which has extremely low ductility and shape *** the other hand,both samples showed a strain-softening phenomenon that does not commonly occur at room *** deformation microstructures revealed that dynamic recovery(DRV)and dynamic recrystallization(DRX)phenomena were generated despite being deformed at room *** on the above findings,the overall deformation mechanisms according to the carrier gas species in the CSAM copper manufacturing process were ***,the work hardening and softening behaviors of CSAM Cu are predicted by using a constitutive equation.

关键词： Cold spray additive manufacturing Carrier gas Pure Cu Mechanical properties Deformation behavior

The KDM4B–CCAR1–MED1 axis is a critical regulator of osteoclast differentiation and bone homeostasis

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Bone Research 2021年第3期9卷 323-335页

作者： Sun-Ju Yi You-Jee Jang Hye-Jung kim Kyubin Lee Hyerim Lee Yeojin kim Junil kim Seon young Hwang Jin sook Song Hitoshi Okada Jae-Il Park Kyuho Kang Kyunghwan kim Department of Biological Sciences and Biotechnology Chungbuk National UniversityCheongjuChungbukRepublic of Korea Korea Basic Science Institute Gwangju Center at Chonnam National UniversityGwangjuRepublic of Korea New Drug Development Center KBIO Osong Medical Innovation FoundationCheongjuChungbukRepublic of Korea Data Convergence Drug Research Center Therapeutics&Biotechnology DivisionKorea Research Institute of Chemical TechnologyDaejeonRepublic of Korea Department of Biochemistry Kindai University Faculty of MedicineOsakasayamaOsakaJapan

Bone undergoes a constant and continuous remodeling process that is tightly regulated by the coordinated and sequential actions of bone-resorbing osteoclasts and bone-forming *** studies have shown that histone demethylases are implicated in osteoblastogenesis;however,little is known about the role of histone demethylases in osteoclast ***,we identified KDM4B as an epigenetic regulator of osteoclast *** of KDM4B significantly blocked the formation of tartrate-resistant acid phosphatase-positive multinucleated *** with myeloid-specific conditional knockout of KDM4B showed an osteopetrotic phenotype due to osteoclast *** analysis revealed that KDM4B physically and functionally associates with CCAR1 and MED1 in a *** genome-wide chromatin immunoprecipitation(ChIP)-sequencing,we revealed that the KDM4B–CCAR1–MED1 complex is localized to the promoters of several osteoclast-related genes upon receptor activator of NF-κB ligand *** demonstrated that the KDM4B–CCAR1–MED1 signaling axis induces changes in chromatin structure(euchromatinization)near the promoters of osteoclast-related genes through H3K9 demethylation,leading to NF-κB p65 recruitment via a direct interaction between KDM4B and ***,small molecule inhibition of KDM4B activity impeded bone loss in an ovariectomized mouse *** together,our findings establish KDM4B as a critical regulator of osteoclastogenesis,providing a potential therapeutic target for osteoporosis.

关键词： formation. critical MED1

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Stabilized sub-grain and nano carbides-driven 1.2 GPa grade ultra-strong CrMnFeCoNi high-entropy alloy additively manufactured by laser powder bed fusion

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Journal of Materials Science & Technology 2022年第22期117卷 8-22页

作者： young-Kyun kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea Korea Institute of Materials Science(kimS) Changwon 51508Republic of Korea

High-entropy alloys(HEAs)with interstitial atoms that are produced by additive manufacturing have gained intensive interest in the materials science community because of their suitability for constructing high-strength net-shape ***,a strategy to additionally enhance the strength of selective laser melted carbon-containing HEAs was *** as-built carbon-containing HEAs(C_(x)(Cr_(20)Mn_(20)Fe_(20)Co_(20)Ni_(20))_(100-x)(x=0.5 at.%,1.0 at.%,and 1.5 at.%))contain supersaturated carbon,and the extent of supersaturation increases as the carbon content *** subjected to aging treatment at 650°C for 1 h,the microstructure of the three alloys did not change at the grain ***,the microstructure at the sub-grain scale changed markedly,and these changes influenced the tensile properties and deformation *** particular,the tensile strength of aged 1.5C-HEA at 650°C was∼1.2 GPa at room temperature,which is higher than those reported for CrMnFeCoNi ***,the main deformation mechanism changed from deformation twinning to dislocation-mediated slip,resulting in much higher strain hardening capacity after the aging *** work led to the development of an alternative promising method that involves tailoring the microstructure,to enhance the mechanical properties of additively manufactured metallic materials that contain interstitial atoms.

关键词： Selective laser melting High-entropy alloy Carbon contents Aging Microstructure evolution Tensile property Deformation mechanism

A paintable and adhesive hydrogel cardiac patch with sustained release of ANGPTL4 for infarcted heart repair

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Bioactive Materials 2024年第1期31卷 395-407页

作者： Mingyu Lee Yong sook kim Junggeon Park Goeun Choe Sanghun Lee Bo Gyeong Kang Ju Hee Jun Yoonmin Shin Minchul kim youngkeun Ahn Jae young Lee School of Materials Science and Engineering Gwangju Institute of Science and TechnologyGwangju61005Republic of Korea Cell Regeneration Research Center Chonnam National UniversityGwangjuRepublic of Korea Biomedical Research Institute Chonnam National University HospitalGwangjuRepublic of Korea Department of Cardiology Chonnam National University HospitalGwangjuRepublic of Korea Chonnam National University Medical School GwangjuRepublic of Korea

The infarcted heart undergoes irreversible pathological remodeling after reperfusion involving left ventricle dilation and excessive inflammatory reactions in the infarcted heart,frequently leading to fatal functional *** attempts have been made to attenuate pathological remodeling in infarcted hearts using cardiac patches and anti-inflammatory drug *** this study,we developed a paintable and adhesive hydrogel patch using dextran-aldehyde(dex-ald)and gelatin,incorporating the anti-inflammatory protein,ANGPTL4,into the hydrogel for sustained release directly to the infarcted heart to alleviate *** optimized the material composition,including polymer concentration and molecular weight,to achieve a paintable,adhesive hydrogel using 10%gelatin and 5%dex-ald,which displayed in-situ gel formation within 135 s,cardiac tissue-like modulus(40.5 kPa),suitable tissue adhesiveness(4.3 kPa),and excellent mechanical ***4 was continuously released from the gelatin/dex-ald hydrogel without substantial burst *** gelatin/dex-ald hydrogel could be conveniently painted onto the beating heart and degraded in ***,in vivo studies using animal models of acute myocardial infarction revealed that our hydrogel cardiac patch containing ANGPTL4 significantly improved heart tissue repair,evaluated by echocardiography and histological *** heart tissues treated with ANGPTL4-loaded hydrogel patches exhibited increased vascularization,reduced inflammatory macrophages,and structural maturation of cardiac *** novel hydrogel system,which allows for facile paintability,appropriate tissue adhesiveness,and sustained release of anti-inflammatory drugs,will serve as an effective platform for the repair of various tissues,including heart,muscle,and cartilage.

关键词： Cardiac patch Hydrogel Angiopoietin-like 4 Myocardial infarction

Environmental Sound Event Detection in Wireless Acoustic Sensor Networks for Home Telemonitoring

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China Communications 2017年第9期14卷 1-10页

作者： Hyoung-Gook kim Jin young kim The Dept. of Electronics Convergence Engineering Kwangwoon University The Dept. of Electronics and Computer Engineering Chonnam National University

In this paper, we present an approach to improve the accuracy of environmental sound event detection in a wireless acoustic sensor network for home monitoring. Wireless acoustic sensor nodes can capture sounds in the home and simultaneously deliver them to a sink node for sound event detection. The proposed approach is mainly composed of three modules, including signal estimation, reliable sensor channel selection, and sound event detection. During signal estimation, lost packets are recovered to improve the signal quality. Next, reliable channels are selected using a multi-channel cross-correlation coefficient to improve the computational efficiency for distant sound event detection without sacrificing performance. Finally, the signals of the selected two channels are used for environmental sound event detection based on bidirectional gated recurrent neural networks using two-channel audio features. Experiments show that the proposed approach achieves superior performances compared to the baseline.

关键词： sound event detection wirelesssensor network gated recurrent neural net-work multichannel audio