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Photonics Research 2022年第2期10卷 365-372页

作者： Changmin Ahn Yongjin Na Minji hyun Jinho Bae Jungwon kim School of Mechanical and Aerospace Engineering Korea Advanced Institute of Science and Technology(KAIST)Daejeon 34141Republic of Korea

Precise and stable synchronization between an optical frequency comb(femtosecond mode-locked laser oscillator or microresonator-based comb) and a microwave oscillator is important for various fields including telecommunication, radio astronomy, metrology, and ultrafast X-ray and electron science. Timing detection and synchronization using electro-optic sampling with an interferometer has been actively used for low-noise microwave generation, long-distance timing transfer, comb stabilization, time-of-flight sensing, and laser-microwave synchronization for ultrafast science facilities. Despite its outstanding performance, there has been a discrepancy in synchronization performance of more than 10 dB between the projected shot-noise-limited noise floor and the measured residual noise floor. In this work, we demonstrate the shot-noise-limited performance of an electro-optic timing detector-based comb-microwave synchronization, which enabled an unprecedented residual phase noise floor of -174.5 dBc∕Hz at 8 GHz carrier frequency(i.e., 53 zs∕Hz^(1/2)timing noise floor), integrated rms timing jitter of 88 as(1 Hz to 1 MHz), rms timing drift of 319 as over 12 h, and frequency instability of 3.6 × 10^(-20) over 10,000 s averaging time. We identified that bandpass filtering of the microwave signal and optical pulse repetition-rate multiplication are critical for achieving this performance.

关键词： synchronization interferometer Synchronization

Topology optimization of reactive material structures for penetrative projectiles

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Defence Technology（防务技术） 2022年第7期18卷 1205-1218页

作者： Shinyu kim Saekyeol kim Taekyun kim Sangin Choi Tae Hee Lee Jung Su Park Sang-hyun Jung Department of Automotive Engineering Hanyang University222 Wangsimni-roSeongdong-guSeoul04763Republic of Korea The 4th R&D Institute Agency for Defense Development35Yuseong P.O.BoxDaejeon34186Republic of Korea

Recently,reactive materials have been developed for penetrative projectiles to improve impact resistance and energy ***,the design of a reactive material structure,involving shape and size,is challenging because of difficulties such as high non-linearity of impact resistance,manufacturing limitations of reactive materials and high expenses of penetration *** this study,a design optimization methodology for the reactive material structure is developed based on the finite element analysis.A finite element model for penetration analysis is introduced to save the expenses of the *** resistance is assessed through the analysis,and result is calibrated by comparing with experimental *** on the model,topology optimization is introduced to determine shape of the *** design variables and constraints of the optimization are proposed considering the manufacturing limitations,and the optimal shape that can be manufactured by cold spraying is *** on the optimal shape,size optimization is introduced to determine the geometric dimensions of the *** a result,optimal design of the reactive material structure and steel case of the penetrative projectile,which maximizes the impact resistance,is *** the design process proposed in this study,reactive material structures can be designed considering not only mechanical performances but also manufacturing limitations,with reasonable time and cost.

关键词： Reactive material Penetrative projectile Topology optimization Manufacturing constraint Cold gas dynamic spray Additive manufacturing

Electrochemical partial reduction of Ni(OH)_(2) to Ni(OH)_(2)/Ni via coupled oxidation of an interfacing NiAl intermetallic compound for robust hydrogen evolution

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Journal of Energy Chemistry 2023年第7期82卷 560-571,I0012页

作者： Young Hwa Yun Kwangsoo kim Changsoo Lee Byeong-Seon An Ji Hee Kwon Sechan Lee MinJoong kim Jongsu Seo Jong Hyeok Park Byung-hyun kim hyun-Seok Cho Hydrogen Research Department Korea Institute of Energy Research152 Gajeong-roYuseong-guDaejeon 34129Republic of Korea Computational Science&Engineering Laboratory Korea Institute of Energy Research152 Gajeong-roYuseong-guDaejeon 34129Republic of Korea Analysis Center for Energy Research Korea Institute of Energy Research152 Gajeong-roYuseong-guDaejeon 34129Republic of Korea Department of Chemical and Biomolecular Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul 03722Republic of Korea

Ni-based porous electrocatalysts have been widely used in the hydrogen evolution reaction(HER)in alkaline water electrolysis,and the catalysts are produced by selective leaching of Al from Ni-Al *** is well known that chemical leaching of Ni-Al intermetallic compound(IMC)generates a high surface area in Ni(OH)_(2).However,the Ni(OH)_(2) produced by leaching the Ni-Al intermetallic compound retards the hydrogen evolution reaction,which is attributed to its weak hydrogen adsorption *** this study,we controlled the chemical state of Ni using plasma vapor deposition(PVD)followed by heat treatment,selective Al leaching,and electrochemical reduction.X-ray diffraction(XRD),scanning microscopy(SEM),transmission electron microscopy(TEM),and energy-dispersive X-ray spectroscopy(EDS)were used to confirm the phase evolution of the electrocatalysts during *** reveal that the heat-treated Ni-Al alloy with a thick Ni2Al3surface layer underwent selective Al leaching and produced biphasic interfaces comprising Ni(OH)_(2) and NiAl IMCs at the edges of the grains in the outermost surface *** oxidation of the interfacing NiAl IMCs facilitated the partial reduction of Ni(OH)_(2) to Ni(OH)_(2)/Ni in the grains during electrochemical reduction,as confirmed by X-ray photoelectron spectroscopy(XPS).An electrocatalyst containing partially reduced Ni(OH)_(2)/Ni exhibited an overpotential of 54 mV at 10 mA/cm^(2) in a half-cell measurement,and a cell voltage of 1.675 V at 0.4 A/cm2for single-cell operation.A combined experimental and theoretical study(density functional theory calculations)revealed that the superior HER activity was attributed to the presence of partially reduced metallic Ni with various defects and residual Al,which facilitated water adsorption,dissociation,and finally hydrogen evolution.

关键词： Raney nickel HERChemical leaching Intrinsic activity Partial reduction

Intraperitoneal chemotherapy for gastric cancer:A contemporary perspective

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Chinese Journal of Cancer Research 2023年第1期35卷 15-18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

StageⅣgastric cancer and peritoneal metastasis Gastric cancer is one of the most common malignancies worldwide and is a leading cause of cancer-related deaths(1).Over the past few decades,advances in surgical techniq... 详细信息

关键词： chemotherapy gastric cancer

Enhancing the Prediction of User Satisfaction with Metaverse Service Through Machine Learning

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Computers, Materials & Continua 2022年第9期72卷 4983-4997页

作者： Seon Hong Lee Haein Lee Jang hyun kim Department of Applied Artificial Intelligence/Department of Human-Artificial Intelligence Interaction Sungkyunkwan UniversitySeoul03063Korea Department of Interaction Science/Department of Human-Artificial Intelligence Interaction Sungkyunkwan UniversitySeoul03063Korea

Metaverse is one of the main technologies in the daily lives of several people,such as education,tour systems,and mobile application ***,the number of users of mobile metaverse applications is increasing owing to the merit of accessibility *** provide an improved service,it is important to analyze online reviews that contain user *** previous studies have utilized traditional methods,such as the structural equation model(SEM)and technology acceptance method(TAM)for exploring user satisfaction,using limited survey *** methods may not be appropriate for analyzing the users of mobile *** overcome this limitation,several researchers perform user experience analysis through online reviews and star ***,some online reviews occasionally have inconsistencies between the star rating and the sentiment of the *** variation disturbs the performance of machine *** alleviate the inconsistencies,Valence Aware Dictionary and sEntiment Reasoner(VADER),which is a sentiment classifier based on lexicon,is *** current study aims to build a more accurate sentiment classifier based on machine learning with *** this study,five sentiment classifiers are used,such as Naïve Bayes,K-Nearest Neighbors(KNN),Logistic Regression,Light Gradient Boosting Machine(LightGBM),and Categorical boosting algorithm(Catboost)with three embedding methods(Bag-of-Words(BoW),Term Frequency-Inverse Document Frequency(TF-IDF),Word2Vec).The results show that classifiers that apply VADER outperform those that do not apply VADER,excluding one classifier(Logistic Regression with Word2Vec).Moreover,LightGBM with TF-IDF has the highest accuracy 88.68%among other models.

关键词： Metaverse ubiquitous computing user satisfaction online review big data VADER machine learning natural language processing

Applying Job Shop Scheduling to SMEs Manufacturing Platform to Revitalize B2B Relationship

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Computers, Materials & Continua 2023年第3期74卷 4901-4916页

作者： Yeonjee Choi hyun Suk Hwang Chang Soo kim Department of Information Systems Pukyong National UniversityBusan608737Korea Research Center Hanyoung DSInc.Seoul07600Korea

A small and medium enterprises(SMEs)manufacturing platform aims to perform as a significant revenue to SMEs and vendors by providing scheduling and monitoring *** optimal job shop scheduling is generated by utilizing the scheduling system of the platform,and a minimum production time,i.e.,makespan decides whether the scheduling is optimal or *** scheduling result allows manufacturers to achieve high productivity,energy savings,and customer *** in Industry 4.0 requires dynamic,uncertain,complex production environments,and customer-centered *** paper proposes a novel method for solving the difficulties of the SMEs manufacturing by applying and implementing the job shop scheduling system on a SMEs manufacturing *** primary purpose of the SMEs manufacturing platform is to improve the B2B relationship between manufacturing companies and *** platform also serves qualified and satisfactory production opportunities for buyers and producers by meeting two key factors:early delivery date and fulfillment of processing as many orders as *** genetic algorithm(GA)-based scheduling method results indicated that the proposed platform enables SME manufacturers to obtain optimized schedules by solving the job shop scheduling problem(JSSP)by comparing with the real-world data from a textile weaving factory in South *** proposed platform will provide producers with an optimal production schedule,introduce new producers to buyers,and eventually foster relationships and mutual economic interests.

关键词： Manufacturing platform job shop scheduling problem(JSSP) genetic algorithm optimization textile process

Optimal concentration of mesenchymal stem cells for fracture healing in a rat model with long bone fracture

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World Journal of Stem Cells 2022年第12期14卷 839-850页

作者： Myung-Seo kim hyun-Ju Chung Kang-Il kim Department of Orthopaedic Surgery School of MedicineKyung Hee University and Kyung Hee University Hospital at GangdongSeoul 05278South Korea Department of Core Research Laboratory Clinical Research InstituteKyung Hee University Hospital at GangdongSeoul 05278South Korea

BACKGROUND There is still no consensus on which concentration of mesenchymal stem cells(MSCs)to use for promoting fracture healing in a rat model of long bone *** To assess the optimal concentration of MSCs for promoting fracture healing in a rat *** Wistar rats were divided into four groups according to MSC concentrations:Normal saline(C),2.5×10^(6)(L),5.0×10^(6)(M),and 10.0×10^(6)(H)*** MSCs were injected directly into the fracture *** rats were sacrificed at 2 and 6 wk *** bone formation[bone volume(BV)and percentage BV(PBV)]was evaluated using micro-computed tomography(CT).Histological analysis was performed to evaluate fracture healing *** protein expression of factors related to MSC migration[stromal cell-derived factor 1(SDF-1),transforming growth factor-beta 1(TGF-β1)]and angiogenesis[vascular endothelial growth factor(VEGF)]was evaluated using western blot *** expression of cytokines associated with osteogenesis[bone morphogenetic protein-2(BMP-2),TGF-β1 and VEGF]was evaluated using real-time polymerase chain *** Micro-CT showed that BV and PBV was significantly increased in groups M and H compared to that in group C at 6 wk post-fracture(P=0.040,P=0.009;P=0.004,P=0.001,respectively).Significantly more cartilaginous tissue and immature bone were formed in groups M and H than in group C at 2 and 6 wk post-fracture(P=0.018,P=0.010;P=0.032,P=0.050,respectively).At 2 wk post fracture,SDF-1,TGF-β1 and VEGF expression were significantly higher in groups M and H than in group L(P=0.031,P=0.014;P<0.001,P<0.001;P=0.025,P<0.001,respectively).BMP-2 and VEGF expression were significantly higher in groups M and H than in group C at 6 wk postfracture(P=0.037,P=0.038;P=0.021,P=0.010).Compared to group L,TGF-β1 expression was significantly higher in groups H(P=0.016).There were no significant differences in expression levels of chemokines related to MSC migration,angiogenesis and cytokines associated

关键词： Rat model Femoral shaft fracture Mesenchymal stem cells Direct injection Optimal concentration Fracture healing

Estimation of marine winds in and around typhoons using multi-platform satellite observations: Application to Typhoon Soulik (2018)

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Frontiers of Earth Science 2022年第1期16卷 175-189页

作者： Seung-Woo LEE Sung hyun NAM Duk-Jin kim School of Earth and Environmental Sciences College of Natural SciencesSeoul National UniversitySeoul 08826Republic of Korea Research Institution of Oceanography College of Natural SciencesSeoul National UniversitySeoul 08826Republic of Korea

Estimating horizontal winds in and around typhoons is important for improved monitoring and prediction of typhoons and mitigating their ***,we present a new algorithm for estimating typhoon winds using multiple satellite observations and its application to Typhoon Soulik(2018).Four kinds of satellite remote sensing data,along with their relationship to typhoon intensity,derived statistically from hundreds of historical typhoon cases,were merged into the final product of typhoon wind(MT wind):(1)geostationarysatellite-based infrared images(IR wind),(2)passive microwave sounder(MW wind),(3)feature-tracked atmospheric motion vectors,and (4)scatterometer-based sea surface winds(SSWs).The algorithm was applied to two cases(A and B)of Typhoon Soulik and validated against SSWs independently retrieved from active microwave synthetic aperture radar(SAR)and microwave radiometer(AMSR2)images,and vertical profiles of wind speed derived from reanalyzed data and dropsonde *** Case A(open ocean),the algorithm estimated the realistic maximum wind,radius of maximum wind,and radius of 15 m/s,which could not be estimated using the reanalysis data,demonstrating reasonable and practical ***,for Case B(when the typhoon rapidly weakened just before making landfall in the Korean Peninsula),the algorithm significantly overestimated the parameters,primarily due to the overestimation of typhoon *** study highlights that realistic typhoon winds can be monitored continuously in real-time using multiple satellite observations,particularly when typhoon intensity is reasonably well predicted,providing timely analysis results and products of operational importance.

关键词： sea surface wind multi-platform satellites Typhoon Soulik(2018)

Pyrimidine nucleotide starvation induces a decrease in the number of effector T cells but not memory T cells

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Cellular & Molecular Immunology 2023年第8期20卷 859-860页

作者： Gwanghun kim hyun Mu Shin Hang-Rae kim Department of Biomedical Sciences Seoul National University College of MedicineSeoul03080Republic of Korea Department of Anatomy&Cell Biology Seoul National University College of MedicineSeoul03080Republic of Korea BK21 FOUR Biomedical Science Project Department of Anatomy&Cell BiologySeoul National University College of MedicineSeoul03080Republic of Korea Medical Research Institute Seoul National University College of MedicineSeoul03080Republic of Korea Wide River Institute of Immunology Seoul National UniversityHongcheon25159Republic of Korea

Scherer et *** the influence of de novo pyrimidine nucleotide synthesis on T-cell responses after antigen stimulation,particularly on effector and memory T-cell development[1].Their work focused on the effect of leflunomide(trade name Avara®),which is a direct inhibitor of dihydroorotate dehydrogenase(DHODH;a key enzyme in the de novo pyrimidine nucleotide pathway and located on the inner mitochondrial membrane).In this pathway,DHODH converts dihydroorotate to orotate and has been implicated in the reduction of ubiquinol to ubiquinone mediated by Complex III in the electron transport *** metabolic effects of DHODH inhibition are unclear[2,3].However,it is known to block S-phase progression by activating *** was originally approved for the treatment of rheumatoid arthritis(RA)in 1998;the mechanism involves the induction of S-phase cell cycle arrest and apoptosis,inhibiting cell proliferation and *** studies have demonstrated the therapeutic potential of leflunomide for cancer[4].Despite the efficacy of leflunomide,the mechanism by which it targets immune cells in the treatment of RA was unknown;however,the work of Scherer and colleagues has shed new light on this mechanism.

关键词： mechanism rotate convert

Brassinosteroids enhance salicylic acid-mediated immune responses by inhibiting BIN2 phosphorylation of clade I TGA transcription factors in Arabidopsis

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Molecular Plant 2022年第6期15卷 991-1007页

作者： Yeong-Woo kim Ji-hyun Youn Jeehee Roh Jeong-Mok kim Seong-Ki kim Tae-Wuk kim Department of Life Science Hanyang UniversitySeoul 04763Republic of Korea Department of Life Science Chung-Ang UniversitySeoul 06973Republic of Korea Research Institute for Convergence of Basic Science Hanyang UniversitySeoul 04763Republic of Korea Hanyang Institute of Bioscience and Biotechnology Hanyang UniversitySeoul 04763Republic of Korea

Salicylic acid (SA) plays an important role in plant immune response, including resistance to pathogens and systemic acquired resistance. Two major components, NONEXPRESSOR OF PATHOGENESIS-RELATED GENES (NPRs) and TGACG motif-binding transcription factors (TGAs), are known to mediate SA signaling, which might also be orchestrated by other hormonal and environmental changes. Nevertheless, the molecular and functional interactions between SA signaling components and other cellular signaling pathways remain poorly understood. Here we showed that the steroid plant hormone brassinosteroid (BR) promotes SA responses by inactivating BR-INSENSITIVE 2 (BIN2), which inhibits the redox-sensitive clade I TGAs in Arabidopsis. We found that both BR and the BIN2 inhibitor bikinin synergistically increase SA-mediated physiological responses, such as resistance to Pst DC3000. Our genetic and biochemical analyses indicated that BIN2 functionally interacts with TGA1 and TGA4, but not with other TGAs. We further demonstrated that BIN2 phosphorylates Ser-202 of TGA4, resulting in the suppression of the redox-dependent interaction between TGA4 and NPR1 as well as destabilization of TGA4. Consistently, transgenic Arabidopsis overexpressing TGA4-YFP with a S202A mutation displayed enhanced SA responses compared to the wild-type TGA4-YFP plants. Taken together, these results suggest a novel crosstalk mechanism by which BR signaling coordinates the SA responses mediated by redox-sensitive clade I TGAs.

关键词： brassinosteroid salicylic acid immune responses BIN2 clade I TGA