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Finite Group Action and Gromov-Witten Invariants in Symplectic Four-Manifolds

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Acta Mathematica Sinica,English Series 2010年第12期26卷 2325-2334页

作者： yong Seung cho Department of Mathematics Ewha Womans University

Let a finite group act semi-freely on a closed symplectic four-manifold with a 2-dimensional fixed point set. Then we show that the relative Gromov-Witten invariants are the same as the invariants on the quotient set-... 详细信息

关键词： Finite group action Gromov-Witten invariant symplectic four-manifold

Thermodynamic model for deoxidation of liquid steel considering strong metal-oxygen interaction in the quasichemical model framework

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International Journal of Minerals,Metallurgy and Materials 2024年第5期31卷 988-1002页

作者： yong-Min cho Youn-Bae kang Graduate Institute of Ferrous and Eco Materials Technology Pohang University of Science and TechnologyPohangKyungbuk37673Rep.of Korea N.EX.T Hub POSCO HoldingsPohangKyungbuk37673Rep.of Korea Department of Materials Science and Engineering Pohang University of Science and TechnologyPohangKyungbuk37673Rep.of Korea

Herein,a thermodynamic model aimed at describing deoxidation equilibria in liquid steel was *** model provides explicit forms of the activity coefficient of solutes in liquid steel,eliminating the need for the minimization of internal Gibbs energy preliminarily when solving deoxidation *** elimination of internal Gibbs energy minimization is particularly advantageous during the coupling of deoxidation equilibrium calculations with computationally intensive approaches,such as computational fluid *** model enables efficient calculations through direct embedment of the explicit forms of activity coefficient in the computing *** proposed thermodynamic model was developed using a quasichemical approach with two key approximations:random mixing of metallic elements(Fe and oxidizing metal) and strong nonrandom pairing of metal and oxygen as nearest *** these approximations,the quasichemical approach yielded the activity coefficients of solutes as explicit functions of composition and temperature without requiring the minimization of internal Gibbs energy or the coupling of separate *** model was successfully applied in the calculation of deoxidation equilibria of various elements(Al,B,C,Ca,Ce,Cr,La,Mg,Mn,Nb,Si,Ti,V,and Zr).The limitations of the model arising from these assumptions were also discussed.

关键词： deoxidation equilibria thermodynamics quasichemical approach computational fluid dynamics

Discreteness of Flux Groups

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Acta Mathematica Sinica,English Series 2006年第1期22卷 115-122页

作者： yong Seung cho Myung Im LIM Department of Mathematics Ewha Women's-University Seoul 120-750 Korea

Let （M, ω） be a closed symplectic 2n-dimensional manifold. Donaldson in his paper showed that there exist 2m-dimensional symplectie submanifolds （V^2m,ω） of （M,ω）, 1 ≤m ≤ n - 1, with （m - 1）-equivalent inclusions. On the basis of this fact we obtain isomorphic relations between kernel of Lefschetz map of M and kernels of Lefschetz maps of Donaldson submanifolds V^2m, 2 ≤ m ≤ n - 1. Then, using this relation, we show that the flux group of M is discrete if the action of π1 （M） on π2（M） is trivial and there exists a retraction r ： M→ V, where V is a 4-dimensional Donaldson submanifold. And, in the symplectically aspherical case, we investigate the flux groups of the manifolds.

关键词： Symplectic diffeomorphisms Flux Symplectically aspherical manifold Donaldson submanifold

Survival analysis based on human epidermal growth factor 2 status in stage Ⅱ-Ⅲ gastric cancer

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World Journal of Gastroenterology 2017年第41期23卷 7407-7414页

作者： Jang Ho cho Jae Yun Lim Jae yong cho Division of Medical Oncology Department of Internal Medicine Gangnam Severance Hospital Yonsei University College of Medicine

AIM To investigate human epidermal growth factor 2(HER2) overexpression and validate its prognostic effect in stage Ⅱ-Ⅲ gastric *** We reviewed the data of patients who were diagnosed with gastric cancer between March 2008 and October 2013 at the Yonsei University Medical Center. Among these patients, 384 patients who met the inclusion criteria were analyzed retrospectively. RESULTS Thirty-two(8.3%) of the 384 stage Ⅱ-Ⅲ gastric cancer patients exhibited HER2 overexpression. The median follow-up duration was 26.0 mo. HER2-negative patients had superior recurrence-free survival(RFS) compared to HER2-positive patients(HR = 0.52, 95%CI: 0.30-0.89; P = 0.015). The median overall survival(OS) was significantly prolonged in the HER2-negative group compared with the HER2-positive group(55.0 mo vs 38.0 mo, HR = 0.43, 95%CI: 0.21-0.88, P = 0.021). OS was also prolonged in HER2-negative patients who received adjuvant chemotherapy compared to HER2-positive patients(55.0 vs 38.0mo, HR = 0.42, 95%CI: 0.18-1.00, P = 0.051). In patients who did not receive adjuvant chemotherapy,the median RFS was prolonged in the HER2-negative group compared to the HER2-positive group(not reached vs 12.0 mo, HR = 0.17, 95%CI: 0.06-0.49, P= 0.001). In a multivariate analysis, HER2 status(HR= 0.421, 95%CI: 0.206-0.861, P = 0.018) and Eastern Cooperative Oncology Group performance status(HR = 2.002, 95%CI: 1.530-2.618, P < 0.001) were independent predictors of *** Our findings showed that HER2-positive patients had inferior OS and RFS. Stage Ⅱ-Ⅲ HER2-positive patients might be potential candidates for targeted therapies involving trastuzumab.

关键词： Trastuzumab Gastric neoplasm Human epidermal growth factor 2

Ion shielding functional separator using halloysite containing a negative functional moiety for stability improvement of Li–S batteries

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Journal of Energy Chemistry 2021年第9期30卷 334-340页

作者： yong Min kwon Jihoon kim kuk Young cho Sukeun Yoon Division of Advanced Materials Engineering&Institute for Rare Metals Kongju National UniversityChungnam 31080Republic of Korea Department of Materials Science and Chemical Engineering Hanyang UniversityGyeonggi 15588Republic of Korea

Lithium–sulfur batteries are one of the attractive next-generation energy storage systems owing to theienvironmental friendliness,low cost,and high specific energy ***,the low electrical conductivity of sulfur,shuttling of soluble intermediate polysulfides between electrodes,and low capacitretention have hampered their commercial *** address these issues,we use a halloysitemodulated(H-M)separator in a lithium–sulfur battery to mitigate the shuttling *** H-M separator acts as a mutual Coulombic repulsion in lithium-sulfur batteries,thereby selectively permitting Lions and efficiently suppressing the transfer of undesired lithium polysulfides to the Li anode sideMoreover,the use of halloysite switches the surface of the separator from hydrophobic to hydrophilicconsequently improving the electrolyte wettability and adhesion between the separator and cathodeWhen sulfur-multi-walled carbon nanotube(S-MWCNT)composites are used as cathode active materialsa lithium–sulfur battery with an H-M separator exhibits first discharge and charge capacities of 1587 an1527 m Ah g-1,***,there is a consistent capacity retention up to 100 cyclesAccordingly,our approach demonstrates an economical and easily accessible strategy for commercialization of lithium–sulfur batteries.

关键词： Li–S batteries Halloysite Ion shielding Negative functional moiety Lithium polysulfides

Influence of haze pollution on water-soluble chemical species in PM2.5 and size-resolved particles at an urban site during fall

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Journal of Environmental Sciences 2017年第7期29卷 370-382页

作者： Geun-Hye Yu Yan Zhang Sung-yong cho Seungshik Park Department of Environment and Energy Engineering Chonnam National UniversityGwangju 61186Republic of Korea

To investigate the influence of haze on the chemical composition and formation processes of ambient aerosol particles,PM_（2.5） and size-segregated aerosol particles were collected daily during fall at an urban site of Gwangju,*** the study period,the total concentration of secondary ionic species（SIS） contributed an average of 43.9% to the PM_（2.5） ,whereas the contribution of SIS to the PM_（2.5） during the haze period was 62.3%.The NO_3 and SO^（2-）_4 concentrations in PM_（2.5） during the haze period were highly elevated,being 13.4 and 5.0 times higher than those during non-haze period,*** PM,NO^-_3,SO^（2-）_4,oxalate,water-soluble organic carbon（WSOC）,and humic-like substances（HULIS） had tri-modal size distributions peaks at 0.32,1.0,and 5.2 μm during the non-haze and haze ***,during the non-haze period they exhibited dominant size distributions at the condensation mode peaking at 0.32 μm,while on October 21 when the heaviest haze event occurred,they had predominant droplet mode size distributions peaking at 1.00 μ***,strong correlations of WSOC and HULIS with SO^（2-）_4,oxalate,and k＋at particle sizes of 〈 1.8 μm indicate that secondary processes and emissions from biomass burning could be responsible for WSOC and HULIS *** was found that the factors affecting haze formation could be the local stable synoptic conditions,including the weak surface winds and high surface pressures,the long-range transportation of haze from eastern China and upwind regions of the korean peninsula,as well as the locally emitted and produced aerosol particles.

关键词： Haze pollution Size distribution Secondary ionic species Humic-like substances Stable synoptic conditions

Byte Frequency Based Indicators for Crypto-Ransomware Detection from Empirical Analysis

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Journal of Computer Science & Technology 2022年第2期37卷 423-442页

作者： Geun yong kim Joon-Young Paik Yeongcheol kim Eun-Sun cho Department of Computer Science and Engineering Chungnam National UniversityDaejeon 34134South Korea School of Computer Science and Technology Tiangong UniversityTianjin 300387China

File entropy is one of the major indicators of crypto-ransomware because the encryption by ransomware increases the randomness of file ***,entropy-based ransomware detection has certain limitations;for example,when distinguishing ransomware-encrypted files from normal files with inherently high-level entropy,misclassification is very *** addition,the entropy evaluation cost for an entire file renders entropy-based detection impractical for large *** this paper,we propose two indicators based on byte frequency for use in ransomware detection;these are termed EntropySA and DistSA,and both consider the interesting characteristics of certain file subareas termed“sample areas”(SAs).For an encrypted file,both the sampled area and the whole file exhibit high-level randomness,but for a plain file,the sampled area embeds informative structures such as a file header and thus exhibits relatively low-level randomness even though the entire file exhibits high-level *** and DistSA use“byte frequency”and a variation of byte frequency,respectively,derived from sampled *** indicators cause less overhead than other entropy-based detection methods,as experimentally proven using realistic ransomware *** evaluate the effectiveness and feasibility of our indicators,we also employ three expensive but elaborate classification models(neural network,support vector machine and threshold-based approaches).Using these models,our experimental indicators yielded an average Fl-measure of 0.994 and an average detection rate of 99.46%for file encryption attacks by realistic ransomware samples.

关键词： computer security cryptography machine learning ransomware

Progress of Materials and Devices for Neuromorphic Vision Sensors

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Nano-Micro Letters 2022年第12期14卷 239-271页

作者： Sung Woon cho Chanho Jo yong-Hoon kim Sung kyu Park Department of Electrical and Electronics Engineering Chung-Ang UniversitySeoul 06974Republic of Korea Department of Advanced Components and Materials Engineering Sunchon National UniversitySunchŏnJeonnam 57922Republic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwon 16419Republic of Korea SkkU Advanced Institute of Nanotechnology(SAINT) Sungkyunkwan UniversitySuwon 16419Republic of Korea

The latest developments in bio-inspired neuromorphic vision sensors can be summarized in 3 keywords:smaller,faster,and smarter.(1)Smaller:Devices are becoming more compact by integrating previously separated components such as sensors,memory,and processing *** a prime example,the transition from traditional sensory vision computing to in-sensor vision computing has shown clear benefits,such as simpler circuitry,lower power consumption,and less data redundancy.(2)Swifter:Owing to the nature of physics,smaller and more integrated devices can detect,process,and react to input more *** addition,the methods for sensing and processing optical information using various materials(such as oxide semiconductors)are evolving.(3)Smarter:Owing to these two main research directions,we can expect advanced applications such as adaptive vision sensors,collision sensors,and nociceptive *** review mainly focuses on the recent progress,working mechanisms,image pre-processing techniques,and advanced features of two types of neuromorphic vision sensors based on near-sensor and in-sensor vision computing methodologies.

关键词： In-sensor computing Near-sensor computing Neuromorphic vision sensor Optoelectronic synaptic circuit Optoelectronic synapse

Evaluation of lubrication performance of crank pin bearing in a marine diesel engine

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Friction 2018年第4期6卷 464-471页

作者： Suk Man MOON yong Joo cho Tae Wan kIM School of Mechanical Engineering Pusan National University Department of Mechanical Engineering Pukyong National University

In this study, the lubrication performance of the crank pin bearing in a marine two–stroke diesel engine is evaluated to investigate the adhesional failure on the crank pin bearing. A numerical algorithm for the lubrication analysis considering motion analysis of the crank pin system is developed. The film pressure and thickness for three clearances and three lubricant temperatures are calculated. The results show that the lubricant temperature has a higher effect on film thickness than clearance. In terms of the film parameter, the operating condition that can result in solid–solid contact is investigated. We also suggest the desirable operating conditions of clearance and lubricant temperature to prevent the solid–solid contact.

关键词： crank pin bearing film thickness lubricant film parameter diesel engine