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Re-visiting supersymmetric Janus solutions: a perturbative construction

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Chinese Physics C 2020年第7期44卷 43-54页

作者： Nakwoo kim se-Jin kim Department of Physics and Research Institute of Basic Science Kyung Hee UniversitySeoul 02447Republic of Korea

We construct holographic Janus solutions,which describe a conformal interface in the theory of M2-branes,in four-dimensional gauged supergravities using a perturbative *** particular,we study three Einsteinscalar systems and their BPS equations,which are derived by Bobev,Pilch,and Warner(2014).The actions of our interest are all consistent truncations of D=11 supergravity,chosen to be invariant under SO(4)×SO(4),SU(3)×U(1)×U(1),and G2 symmetry subgroups of SO(8).The utility of our semi-analytic result is illustrated by the calculation of minimal area surface and the associated holographic entanglement entropy.

关键词： holography Janus solutions supergravity entanglement entropy

Depolarization mitigated in ferroelectric Hf_(0.5)Zr_(0.5)O_(2)ultrathin films(<5 nm)on Si substrate by interface engineering

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Journal of Advanced Ceramics 2024年第3期13卷 282-292页

作者： se Hyun kim Younghwan Lee Dong Hyun Lee Geun hyeong Park Hyun Woo Jeong Kun Yang Yong hyeon Cho Young Yong kim Min Hyuk Park Department of Materials Science and Engineering College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Research Institute of Advanced Materials College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Inter-university semiconductor Research Center College of EngineeringSeoul National UniversitySeoul 08826Republic of Korea Pohang Accelerator Laboratory Pohang University of Science&TechnologyPohang 790784Republic of Korea

(Hf,Zr)O_(2)offers considerable potential for next-generation semiconductor devices owing to its nonvolatile spontaneous polarization at the ***,scaling this material to sub-5 nm thickness poses several challenges,including the formation of an interfacial layer and high trap *** particular,a low-k SiO_(2)interfacial layer is naturally formed when(Hf,Zr)O_(2)films are directly grown on a Si substrate,leading to high depolarization fields and rapid reduction of the remanent *** address these issues,we conducted a study to significantly improve ferroelectricity and switching endurance of(Hf,Zr)O_(2)films with sub-5 nm thicknesses by inserting a TiO_(2)interfacial *** deposition of a Ti film prior to Hf_(0.5)Zr_(0.5)O_(2)film deposition resulted in a high-k TiO_(2)interfacial layer and prevented the direct contact of Hf_(0.5)Zr_(0.5)O_(2)with *** findings show that the high-k TiO_(2)interfacial layer can reduce the SiO_(2)/Si interface trap density and the depolarization field,resulting in a switchable polarization of 60.2μC/cm^(2)for a 5 nm thick Hf_(0.5)Zr_(0.5)O_(2)***,we propose that inserting a high-k TiO_(2)interfacial layer between the Hf_(0.5)Zr_(0.5)O_(2)film and the Si substrate may offer a promising solution to enhancing the ferroelectricity and reliability of(Hf,Zr)O_(2)grown on the Si substrate and can pave the way for next-generation semiconductor devices with improved performance.

关键词： ferroelectric charge trapping hafnia depolarization

Boosted Lithium-Ion Transport Kinetics in n-Type Siloxene Anodes Enabled by selective Nucleophilic Substitution of Phosphorus

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Nano-Micro Letters 2024年第10期16卷 618-637页

作者： se In kim Woong-Ju kim Jin Gu Kang Dong-Wan kim School of Civil Environmental and Architectural EngineeringKorea University02841 SeoulSouth Korea Nanophotonics Research Center Korea Institute of Science and Technology02792 SeoulSouth Korea

Doped two-dimensional(2D)materials hold significant promise for advancing many technologies,such as microelectronics,optoelectronics,and energy ***,n-type 2D oxidized Si nanosheets,namely n-type siloxene(n-SX),are employed as Li-ion battery *** thermal evaporation of sodium hypophosphite at 275℃,P atoms are effectively incorporated into siloxene(SX)without compromising its 2D layered morphology and unique Kautsky-type crystal ***,selective nucleophilic substitution occurs,with only Si atoms being replaced by P atoms in the O_(3)≡Si-H *** resulting n-SX possesses two delocalized electrons arising from the presence of two electron donor types:(i)P atoms residing in Si sites and(ii)H *** doping concentrations are varied by controlling the amount of precursors or their mean free *** at 2000 mA g^(-1),the n-SX electrode with the optimized doping concentration(6.7×10^(19) atoms cm^(-3))delivers a capacity of 594 mAh g^(-1) with a 73%capacity retention after 500 *** improvements originate from the enhanced kinetics of charge transport processes,including electronic conduction,charge transfer,and solid-state *** approach proposed herein offers an unprecedented route for engineering SX anodes to boost Li-ion storage.

关键词： Li-ion battery Two-dimensional N-type siloxene Doping mechanism Kinetics

Development of a two-stage virtual impactor for the generation of micrometer-scale monodisperse aerosols

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Particuology 2024年第12期95卷 189-197页

作者： Jun-Hyung Lim Igor kim se-Jin Yook School of Mechanical Engineering Hanyang UniversitySeoul04763Republic of Korea

Monodisperse particles are useful across a wide range of industrial applications,such as LCD displays,solar cells and rechargeable batteries,due to their uniformly small ***,generating high volumes of monodisperse particles remains *** this study,it was aimed to generate mono-disperse aerosols by classifying micrometer-scale solid aerosol particles within a narrow size ***,a new particle-size classification device with two virtual impactors connected in series and clean air cores was *** first-stage virtual impactor had a slightly larger cutoff size than the second-stage,and the major flow discharged from the first-stage was directed to the *** target particle size range was altered by changing the nozzle sizes in the first and second stages or by adjusting the flow ***,the classification performance of the two-stage virtual impactor was simulated and validated through an experiment using Arizona test *** implemented combi-nations of cutoff sizes for the first and second stages were 3.0 and 2.0μm,3.9 and 2.7μm,or 6.7 and 4.8μ*** a result,monodisperse aerosol particles were classified at a geometric standard deviation of 1.04-1.14 and a particle size range of 2-6.7μ*** two-stage virtual impactor developed herein may be useful for various research and performance evaluations,as it can classify micrometer-scale solid particle aerosols that exhibit high monodispersity.

关键词： Virtual impactor Clean air core Dust collection efficiency Monodispersity

Effect of post heat-treatment on the microstructure and high-temperature oxidation behavior of precipitation hardened IN738LC superalloy fabricated by selective laser melting

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Journal of Materials Science & Technology 2021年第17期76卷 95-103页

作者： Kyu-Sik kim Sangsun Yang Myeong-se kim Kee-Ahn Lee Department of Materials Science and Engineering Inha UniversityIncheon 22212Republic of Korea Korea Institute of Materials Science Changwon51508Republic of Korea Auratech Co. Ltd.Seongnam13449Republic of Korea

The present study investigated the effect of as-built and post heat-treated microstructures of IN738LC alloy fabricated via selective laser melting process on high temperature oxidation *** as-built microstructure showed fine cell and columnar structure due to high cooling *** element segregation was observed in inter-cell/inter-columnar *** post heat-treatment,the initially-observed cell structure disappeared,instead bimodal Ni_3(Al,Ti)particles *** temperature(1273 K and 1373 K)oxidation test results showed parabolic oxidation curves regardless of temperature and initial *** as-built IN738LC fabricated via the selective laser melting process displayed oxidation resistance similar to or slightly better than that of IN738LC fabricated via wrought or cast ***-treated SLM IN738LC,although had similar oxidation weight-gain values to those of the SLM asbuilt material at 1273K,showed relatively better oxidation resistance at 1373 *** Ni_3(Al,Ti)precipitate formed in the post heat treatment changed the local chemical composition,thereby led to changes in alumina former/chromia former location and fraction on the alloy *** was concluded that in heat-treated IN738LC increased alumina former fraction was found,and this resulted in excellent oxidation resistance and relatively low weight-gain.

关键词： IN738LC selective laser melting High temperature oxidation Post heat-treatment Oxidation mechanism

Deep Learning Approach for Cosmetic Product Detection and Classification

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Computers, Materials & Continua 2021年第10期69卷 713-725页

作者： se-Won kim Sang-Woong Lee Department of IT Convergence Engineering Gachon UniversitySeongnam13120Korea Department of Software Gachon UniversitySeongnam13120Korea

As the amount of online video content is increasing,consumers are becoming increasingly interested in various product names appearing in videos,particularly in cosmetic-product names in videos related to fashion,beauty,and ***,the identification of such products by using image recognition technology may aid in the identification of current commercial *** this paper,we propose a two-stage deep-learning detection and classification method for cosmetic ***,variants of the YOLO network are used for detection,where the bounding box for each given input product is predicted and subsequently cropped for *** use four state-of-the-art classification networks,namely ResNet,InceptionResNetV2,DenseNet,and EfficientNet,and compare their ***,we employ dilated convolution in these networks to obtain better feature representations and improve *** experiments demonstrate that YOLOv3 and its tiny version achieve higher speed and ***,the dilated networks marginally outperform the base models,or achieve similar performance in the worst *** conclude that the proposed method can effectively detect and classify cosmetic products.

关键词： Cosmetic product detection cosmetic product classification deep learning

Dynamic observation of dendrite growth on lithium metal anode during battery charging/discharging cycles

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npj Computational Materials 2022年第1期8卷 960-972页

作者： Hae Gon Lee se Young kim Joon Sang Lee Next Generation Battery Research Center Korea Electrotechnology Research Institute(KERI)12Jeongiui-gilSeongsan-guChangwon-siGyeongsangnam-do51543Republic of Korea Department of Mechanical Engineering Yonsei University50 Yonsei-roSeodaemun-guSeoul03722Republic of Korea

Lithium metal is considered one of the most promising anode materials for application in next-generation ***,despite decades of research,practical application of lithium metal batteries has not yet been achieved because the fundamental interfacial mechanism of lithium dendrite growth is not yet fully *** this study,a series of reactive molecular dynamics (MD) simulations was performed to investigate the electrochemical dynamic reactions at the electrode/electrolyte *** allows quantitative characterization of morphological phenomena and real-time interfacial visualization of the dynamic growth of dead lithium and dendrites during repeated *** computational protocol was utilized to investigate the dendrite mitigation mechanism when an electrolyte additive (hydrogen fluoride) is dissolved in an organic ethylene carbonate (EC) electrolyte *** was confirmed that beneficial decomposition reactions between electrolyte components form a protective film on the anode surface,suppressing large interphase volume changes and unnecessary degradation reactions.

关键词： battery lithium electrolyte

Voxelated opto-physically unclonable functions via irreplicable wrinkles

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Light(Science & Applications) 2023年第11期12卷 2378-2390页

作者： Kitae kim se-Um kim Moon-Young Choi Mohsin Hassan Saeed Youngmin kim Jun-Hee Na Department of Convergence System Engineering Chungnam National University99 Daehak-roYuseong-guDaejeon 34134Republic of Korea Department of Electrical and Information Engineering Seoul National University of Science&Technology232 Gongneung-roNowon-guSeoul 01811Republic of Korea Department of Electrical Electronicsand Communication Engineering EducationChungnam National University99 Daehak-roYuseong-guDaejeon 34134Republic of Korea Hologram Research Center Korea Electronics Technology InstituteWorld Cup buk-ro 54-gilMapo-guSeoul 03924Republic of Korea

The increased prevalence of the Internet of Things(IoT)and the integration of digital technology into our daily lives have given rise to heightened security risks and the need for more robust security *** response to these challenges,physical unclonable functions(PUFs)have emerged as promising solution,offering a highly secure method to generate unpredictable and unique random digital values by leveraging inherent physical ***,traditional PUFs implementations often require complex hardware and circuitry,which can add to the cost and complexity of the *** present a novel approach using a random wrinkles PUF(rw-PUF)based on an optically anisotropic,facile,simple,and cost-effective *** wrinkles contain randomly oriented liquid crystal molecules,resulting in a two-dimensional retardation map corresponding to a complex birefringence ***,our proposed technique allows for customization based on specific requirements using a spatial light modulator,enabling fast *** random wrinkles PUF has the capability to store multiple data sets within a single PUF without the need for physical ***,we introduce a concept called‘polyhedron authentication,’which utilizes three-dimensional information storage in a voxelated random wrinkles *** approach demonstrates the feasibility of implementing high-level security technology by leveraging the unique properties of the rw-PUF.

关键词： hardware functions utilize

Chemotherapy beyond second-line in advanced gastric cancer

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World Journal of Gastroenterology 2015年第29期21卷 8811-8816页

作者： Sung Min kim se Hoon Park Division of Hematology-Oncology Department of Medicine Sungkyunkwan University Samsung Medical Center

Patients with advanced gastric cancer(AGC) can be treated with multiple lines of chemotherapy. Although several randomized trials have demonstrated the benefit of second-line chemotherapy compared with best supportive care, there is no evidence that further lines of chemotherapy will result in substantial prolongation of survival. Despite this, the practice of offering chemotherapy beyond second-line agents to AGC patients is not uncommon if their performance status is well-preserved and they are willing to receive subsequent active treatments. The choice of chemotherapeutic agents depends on the patient's prior regimens. However, there are important controversial issues in the salvage setting of AGC, including a subset of patients who may benefit from chemotherapy, that still remain unanswered. This report reviews the available evidence regarding the impact of third- and subsequent lines of chemotherapy on survival and quality of life in patients with AGC.

关键词： Chemotherapy Gastric cancer Salvage