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Rare Metals 2024年第1期43卷 280-288页

作者： Kyoung-Joung Yoo Dae-Yun Kang Nahyun kim Ho-Jin Lee Ta-Hyeong kim Taeho kim Tae Geun kim School of Electrical Engineering Korea UniversitySeoul 02841Republic of Korea

The use of electrochemical-metallization-based volatile threshold switching selectors in cross-point arrays has been widely explored owing to their high on-off ratios and simple ***,these devices are unsuitable for cross-point architectures because of the difficulty in controlling the random filament formation that results in large fluctuations in the threshold voltage during *** this study,we investigated the unidirectional threshold transition characteristics associated with an Ag/GST/HfO_(x)/Pt-based bilayer selector and demonstrated the occurrence of a low leakage current(<1×10^(-11) A) and low distribution of the threshold voltage(Δ0.11 V).The bilayer structure could control the filament formation in the intermediate state through the insertion of an HfO_(x) tunneling *** stacking a bilayer selector with NiO_(x)based resistive random-access memory,the leakage and programming currents of the device could be significantly *** the crossbar array configuration,we performed equivalent circuit analysis of a one-selector oneresistor(1S1R) devices and estimated the optimal array size to demonstrate the applicability of the proposed *** maximum acceptable crossbar array size of the 1S1R device with the Ag/GST/HfO_(x)/Pt/Ti/NiO_(x)/Pt structure was 5.29×10^(14)(N^(2),N=2.3×10^(7)).

关键词： Selector device Tunneling barrier Threshold switching Sputtering 1S1R Cross-point array

Trend of Developing Aqueous Liquid and Gel Electrolytes for Sustainable,Safe,and High‑Performance Li‑Ion Batteries

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Nano-Micro Letters 2024年第1期16卷 17-34页

作者： Donghwan Ji Jaeyun kim School of Chemical Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Department of Health Sciences and Technology Samsung Advanced Institute for Health Sciences&Technology(SAIHST)Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Biomedical Institute for Convergence at SKKU(BICS) Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Institute of Quantum Biophysics(IQB) Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Present Address:Department of NanoEngineering University of California San DiegoLa JollaSan DiegoCA 92093USA

Current lithium-ion batteries(LIBs)rely on organic liquid electrolytes that pose significant risks due to their flammability and *** potential for environmental pollution and explosions resulting from battery damage or fracture is a critical ***-based(aqueous)electrolytes have been receiving attention as an alternative to organic ***,a narrow electrochemicalstability window,water decomposition,and the consequent low battery operating voltage and energy density hinder the practical use of aqueous ***,developing novel aqueous electrolytes for sustainable,safe,high-performance LIBs remains *** Review first commences by summarizing the roles and requirements of electrolytes–separators and then delineates the progression of aqueous electrolytes for LIBs,encompassing aqueous liquid and gel electrolyte development trends along with detailed principles of the *** aqueous electrolytes are progressed based on strategies using superconcentrated salts,concentrated diluents,polymer additives,polymer networks,and artificial passivation layers,which are used for suppressing water decomposition and widening the electrochemical stability window of water of the *** addition,this Review discusses potential strategies for the implementation of aqueous Li-metal batteries with improved electrolyte–electrode interfaces.A comprehensive understanding of each strategy in the aqueous system will assist in the design of an aqueous electrolyte and the development of sustainable and safe high-performance batteries.

关键词： Lithium-ion battery(LIB) Aqueous electrolyte Gel electrolyte Electrochemical stability window Li dendrite

Systematic Security Guideline Framework through Intelligently Automated Vulnerability Analysis

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Computers, Materials & Continua 2024年第3期78卷 3867-3889页

作者： Dahyeon kim Namgi kim Junho Ahn Computer Information Technology Korea National University of TransportationChungju27469Korea Department of AI Computer Science and Engineering Kyonggi UniversitySuwon16227Korea

This research aims to propose a practical framework designed for the automatic analysis of a product’s comprehensive functionality and security vulnerabilities,generating applicable guidelines based on real-world *** existing analysis of software security vulnerabilities often focuses on specific features or *** partial and arbitrary analysis of the security vulnerabilities makes it challenging to comprehend the overall security vulnerabilities of the *** key novelty lies in overcoming the constraints of partial *** proposed framework utilizes data from various sources to create a comprehensive functionality profile,facilitating the derivation of real-world security *** guidelines are dynamically generated by associating functional security vulnerabilities with the latest Common Vulnerabilities and Exposure(CVE)and Common Vulnerability Scoring System(CVSS)scores,resulting in automated guidelines tailored to each *** guidelines are not only practical but also applicable in real-world software,allowing for prioritized security *** proposed framework is applied to virtual private network(VPN)software,wherein a validated Level 2 data flow diagram is generated using the Spoofing,Tampering,Repudiation,Information Disclosure,Denial of Service,and Elevation of privilege(STRIDE)technique with references to various papers and examples from related *** analysis resulted in the identification of a total of 121 *** successful implementation and validation demonstrate the framework’s efficacy in generating customized guidelines for entire systems,subsystems,and selected modules.

关键词： Framework automation vulnerability analysis security guidelines

CFD-based hull optimization in calm water using adaptive grid deformation method

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Journal of Hydrodynamics 2024年第2期36卷 241-262页

作者： Shuguang Wang Yonghwan kim Department of Naval Architecture and Ocean Engineering Seoul National UniversitySeoulKorea

This paper presents an adaptive grid deformation technique for optimizing ship hull forms using computational fluid dynamics(CFD).The proposed method enables accurate and smooth updates of the hull surface and 3-D CFD grids in response to design *** technique incorporates a two-level point-transformation approach to move the grid points by a few design ***,generic B-splines are utilized to transform grid points according to the displacements of the control points within a defined control *** ensures surface modification accuracy and smoothness,similar to those provided by non-uniform rational ***,radial basis functions are used to interpolate the movements of the control points with a limited set of design *** developed method effectively maintains the mesh quality and simulation *** applying this method to surface and grid adaptation,a regression model is proposed in the form of a second-order polynomial to represent the relationship between the geometric parameters and design *** polynomial is then used to introduce geometric ***,a radial basis function surrogate model for the calm-water resistance is constructed to approximate the objective *** enhanced optimization framework is proposed for CFD–based hull optimization and applied to KVLCC2 to validate its feasibility and efficiency.

关键词： Hull-form optimization adaptive grid deformation ship resistance OpenFOAM radial basis function(RBF)surrogate model

Fabrication of heteroatom-doped cobalt oxide yolk–shell microsphere using recycled solution from waste materials and their excellent electrochemical properties as an anode material for lithium-ion batteries

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Rare Metals 2024年第10期43卷 4934-4947页

作者： Yeong Beom kim Chanho kim Seung-Hyun kim Yun Chan Kang Dongju Lee Gi Dae Park Department of Advanced Materials Engineering Chungbuk National University Department of Materials Science and Engineering Korea University Research Institute YKSintering Co.Ltd.

Heteroatom-doped transition metal oxides have attracted great attention as advanced anode materials for lithium-ion batteries due to their high theoretical capacity and superior ***,the limited resource availability has led to a substantial rise in prices for valuable metals such as Ni and Co,posing a significant challenge for their *** address this issue,recycling of these metals from waste materials have gained prominence,and particularly the recovery of Co has been mostly focused on its economic ***,we introduced a novel recycling strategy for fabrication of heteroatomdoped CoOx（comprising mainly Co3O4with a minor CoO phase） anode with a yolk–shell structure for lithium-ion batteries,by separating Co from cemented tungsten carbide *** employing a simple leaching process and subsequent spray pyrolysis,the yolk–shell structured microsphere comprising CoOxwas successfully ***,the presence of other waste metals in the leachate facilitated multi-heteroatom doping during ***,the introduction of various dopants into CoOxinduced oxygen vacancy formation,thereby enhancing the electrochemical properties of the *** a result,compared with the phase-pure （undoped） CoOxyolk–shell,the heteroatom-doped CoOxyolk–shell exhibited robust cycling stability (602 mAh·g-1for 200 cycles at 1 A·g-1) and excellent rate capability(210 mAh·g-1at 10 A·g-1).

关键词： Anode Cobalt oxide Heteroatom doping Lithium-ion batteries Recycling

Postmortem ^(7)Li NMR analysis for assessing the reversibility of lithium metal electrodes in lithium metal batteries

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Journal of Energy Chemistry 2024年第7期94卷 430-440页

作者： Jaewon Baek Sunha kim Hee-Tak kim Oc Hee Han Department of Chemical&Biomolecular Engineering KAISTDaejeon 34141Republic of Korea Metropolitan Seoul Center Korea Basic Science InstituteSeoul 03759Republic of Korea Graduate School of Analytical Science&Technology Chungnam National UniversityDaejeon 34134Republic of Korea

Despite the proficiency of lithium(Li)-7 NMR spectroscopy in delineating the physical and chemical states of Li metal electrodes,challenges in specimen preparation and interpretation impede its *** this study,we conducted a comprehensive postmortem analysis utilizing ^(7)Li NMR,employing a stan-dard magic angle spinning probe to examine protective-layer coated Li metal electrodes and LiAg alloy electrodes against bare Li metal electrodes within Li metal batteries(LMBs).Our investigation explores the effects of sample burrs,alignment with the magnetic field,the existence of liquid electrolytes,and precycling on the ^(7)Li NMR *** contrasting NMR spectra before and after cycling,we identi-fied alterations in Li^(0) and Li^(+) signals attributable to the degradation of the Li metal *** NMR analyses decisively demonstrate the efficacy of the protective layer in mitigating dendrite and solid elec-trolyte interphase ***,we noted that Li*ions near the Li metal surface exhibit magnetic susceptibility anisotropy,revealing a novel approach to studying diamagnetic species on Li metal elec-trodes in *** study provides valuable insights and practical guidelines for characterizing distinct lithium states within LMBs.

关键词： NMR spectroscopy Lithium-7 Lithium metal battery Electrolyte Electrode-protective layer Solid electrolyte interface Magnetic susceptibility anisotropy Lithium-metal NMR signal Diamagnetic^(7)Li NMR signal

Intelligent structured nanocomposite adhesive for bioelectronics and soft robots

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Nano Research 2024年第2期17卷 534-549页

作者： Yeon Soo Lee Min-Seok kim Da Wan kim Changhyun Pang School of Chemical Engineering Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea Mechanical Metrology Group Korea Research Institute of Standards and ScienceDaejeon 34113Republic of Korea Department of Electronic Engineering Korea National University of TransportationChungbuk 27469Republic of Korea Samsung Advanced Institute for Health Sciences and Technology Sungkyunkwan University(SKKU)Suwon 16419Republic of Korea

The remarkable functionality of biological systems in detecting and adapting to various environmental conditions has inspired the design of the latest electronics and robots with advanced *** review focuses on intelligent bio-inspired strategies for developing soft bioelectronics and robotics that can accommodate nanocomposite adhesives and integrate them into biological *** underlying principles of the material and structural design of nanocomposite adhesives were investigated for practical applications with excellent functionalities,such as soft skin-attachable health care sensors,highly stretchable adhesive electrodes,switchable adhesion,and untethered soft *** addition,we have discussed recent progress in the development of effective fabrication methods for micro/nanostructures for integration into devices,presenting the current challenges and prospects.

关键词： biomimetics bio-adhesive switchable adhesion bioelectronics nanocomposite soft robotics

A comprehensive review on the resynthesis of ternary cathode active materials from the leachate of Li-ion batteries

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Journal of Energy Chemistry 2024年第8期95卷 446-463,I0010页

作者： Dongwoo kim Hyeoncheol Joo Chanmin kim Seoa kim Wan-Yi kim Sangwoo Han Joongkil Park Soyeon Park Heechul Jung Sanghyuk Park Kyungjung Kwon Department of Energy and Mineral Resources Engineering Sejong UniversitySeoul 05006Republic of Korea LIB Recycling Research Group LIB Materials R&D CenterPOSCO HoldingsPohang 37859Republic of Korea Department of Future Energy Convergence Seoul National University of Science&Technology232 Gongreung-roNowon-guSeoul 01811Republic of Korea Autonomous Intelligent Unmanned Flying Vehicles Institute Sejong UniversitySeoul 05006Republic of Korea

This review highlights the importance of recovering valuable metals from spent Li-ion battery(LIB)cathodes through the resynthesis of cathode active materials(CAMs).The resynthesis process of CAMs,a promising recycling method that directly produces CAM precursors from LIB leachate,is *** process encompasses six key steps,including pretreatment,leaching,purification,adjustment of metal concentrations,precursor synthesis,and *** review also investigates the potential introduction of impurity elements during CAM resynthesis and provides tolerance levels for these impurities based on thorough reference ***,it addresses challenges related to the commercialization of the resynthesis ***,this review represents the first comprehensive assessment of CAM resynthesis,including the systematic evaluation of 12 impurity elements(Fe,Li,Al,Cu,C,P,F,Na,Cl,S,Mg,and Zn).Overall,this comprehensive review is poised to support the commercial development of resynthesized CAMs by offering valuable guidelines for managing impurities and streamlining the purification process.

关键词： Li-ion battery Recycling Resynthesis Leachate Impurity

Retinal artery/arteriole occlusion risks after endovascular treatment for unruptured intracranial aneurysm

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Stroke & Vascular Neurology 2024年第3期9卷 295-305,I0251-I0263页

作者： Hae Rang kim Min Jeoung kim Sunyeup kim Myung Soo Chang Dong Joon kim Byung Moon kim Keun Young Park Yong Bae kim Christopher Seungkyu Lee Suk Ho Byeon Sung Soo kim Seung Won Lee Yong Joon kim Department of Ophthalmology CHA Bundang Medical CenterCHA University College of MedicineSeongnamKorea(the Republic of) Department of Neurosurgery Severance Stroke CenterSeverance HospitalYonsei University College of MedicineSeoulKorea(the Republic of) Department of Neurosurgery Uijeongbu St.Mary’s HospitalThe Catholic University of Korea College of MedicineUijeongbuKorea(the Republic of) Department of Medical AI Sungkyunkwan University School of MedicineSuwonKorea(the Republic of) Department of Ophthalmology Institute of Vision ResearchYonsei University College of MedicineSeoulKorea(the Republic of) Department of Radiology Severance Stroke CenterSeverance HospitalYonsei University College of MedicineSeoulKorea(the Republic of) Department of Precision Medicine Sungkyunkwan University School of MedicineSuwonKorea(the Republic of)

Background To evaluate the association between retinal artery/arteriole occlusion(RAO)and unruptured intracranial aneurysm(UIA).Methods Incident UIA patients from a nationwide cohort(n=253240)were categorised into three groups based on subsequent treatment:observation(n=208993),microsurgical clipping(n=14168)and endovascular treatment(EVT)groups(n=30079).The incidence and the incident time of RAO were *** of RAO and associated risk factors were ***,a hospital cohort comprising 2569 consecutive UIA patients treated at a tertiary hospital was analysed with detailed clinical information of *** In the nationwide cohort analysis,the incidence of RAO was significantly higher in EVT group than in observation and clipping groups,especially within 60 days(early RAO(within 60 days):HR=4.00,95%CI:2.44 to 6.56);delayed RAO(after 60 days:HR=1.74,95%CI:1.13 to 2.68).Multivariable analysis showed that the presence of chronic kidney disease(p=0.009)and use of a balloon microcatheter during the procedure(p=0.013)were associated with a higher risk of *** hospital cohort analysis,11(0.8%)cases of RAO occurred after EVT,whereas none occurred after microsurgical clipping(p<0.001).Patients with RAO were younger and received balloon microcatheters more frequently than their *** cases of RAO(90.9%)occurred in paraclinoid aneurysms,where EVT was preferred over microsurgical *** Performing EVT for UIA may increase the risk of subsequent *** should be taken when treating paraclinoid aneurysms with balloon microcatheters.

关键词： treatment nationwide balloon

Anomaly Detection in Imbalanced Encrypted Traffic with Few Packet Metadata-Based Feature Extraction

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Computer Modeling in Engineering & Sciences 2024年第10期141卷 585-607页

作者： Min-Gyu kim Hwankuk kim Department of Financial Information Security Kookmin UniversitySeoul02707Republic of Korea Department of Information Security Cryptography Mathematics Kookmin UniversitySeoul02707Republic of Korea

In the IoT(Internet of Things)domain,the increased use of encryption protocols such as SSL/TLS,VPN(Virtual Private Network),and Tor has led to a rise in attacks leveraging encrypted *** research on anomaly detection using AI(Artificial Intelligence)is actively progressing,the encrypted nature of the data poses challenges for labeling,resulting in data imbalance and biased feature extraction toward specific *** study proposes a reconstruction error-based anomaly detection method using an autoencoder(AE)that utilizes packet metadata excluding specific node *** proposed method omits biased packet metadata such as IP and Port and trains the detection model using only normal data,leveraging a small amount of packet *** makes it well-suited for direct application in IoT environments due to its low resource *** experiments comparing feature extraction methods for AE-based anomaly detection,we found that using flowbased features significantly improves accuracy,precision,F1 score,and AUC(Area Under the Receiver Operating Characteristic Curve)score compared to packet-based ***,for flow-based features,the proposed method showed a 30.17%increase in F1 score and improved false positive rates compared to Isolation Forest and ***,the proposedmethod demonstrated a 32.43%higherAUCwhen using packet features and a 111.39%higher AUC when using flow features,compared to previously proposed oversampling *** study highlights the impact of feature extraction methods on attack detection in imbalanced,encrypted traffic environments and emphasizes that the one-class method using AE is more effective for attack detection and reducing false positives compared to traditional oversampling methods.

关键词： One-class anomaly detection feature extraction auto-encoder encrypted traffic CICIoT2023