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Stable immobilization of lithium polysulfides using three-dimensional ordered mesoporous Mn_(2)O_(3) as the host material in lithium-sulfur batteries

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Carbon Energy 2024年第6期6卷 99-112页

作者： Sung joon Park Yun Jeong Choi Hyun-seung Kim Min joo Hong Hongjun chang Janghyuk Moon Young-Jun Kim Junyoung Mun Ki Jae Kim Department of Energy Science Sungkyunkwan UniversitySuwonGyeonggi-doRepublic of Korea Department of Energy Engineering Konkuk UniversitySeoulRepublic of Korea Advanced Batteries Research Center Korea Electronic Technology InstituteSeongnamRepublic of Korea Department of Future Energy Engineering Sungkyunkwan UniversitySuwonRepublic of Korea Department of Energy Systems Engineering Chung-Ang UniversitySeoulRepublic of Korea SKKU Advanced Institute of Nanotechnology Sungkyunkwan UniversitySuwonGyeonggi-doRepublic of Korea SKKU Institute of Energy Science and Technology(SIEST) Sungkyunkwan UniversitySuwonRepublic of Korea School of Advanced Materials Science and Engineering Sungkyunkwan UniversitySuwonRepublic of Korea

Lithium-sulfur batteries(LSBs)have drawn significant attention owing to their high theoretical discharge capacity and energy ***,the dissolution of long-chain polysulfides into the electrolyte during the charge and discharge process(“shuttle effect”)results in fast capacity fading and inferior electrochemical *** this study,Mn_(2)O_(3)with an ordered mesoporous structure(OM-Mn_(2)O_(3))was designed as a cathode host for LSBs via KIT-6 hard templating,to effectively inhibit the polysulfide shuttle ***-Mn_(2)O_(3)offers numerous pores to confine sulfur and tightly anchor the dissolved polysulfides through the combined effects of strong polar-polar interactions,polysulfides,and sulfur chain *** OM-Mn_(2)O_(3)/S composite electrode delivered a discharge capacity of 561 mAh g^(-1) after 250 cycles at 0.5 C owing to the excellent performance of OM-Mn_(2)O_(3).Furthermore,it retained a discharge capacity of 628mA h g^(-1) even at a rate of 2 C,which was significantly higher than that of a pristine sulfur electrode(206mA h g^(-1)).These findings provide a prospective strategy for designing cathode materials for high-performance LSBs.

关键词： host material lithium-sulfur battery ordered mesoporous structure shuttle effect transition-metal oxides

Ruptured venous aneurysm associated with a dural arteriovenous fistula:Two case reports

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World Journal of Clinical Cases 2024年第29期12卷 6314-6319页

作者： You Sub Kim Woong Yoon Byung Hyun Baek Seul kee Kim Sung Pil joo Tae Sun Kim Department of Neurosurgery Chonnam National University Hospital and Medical SchoolGwangju 61469South Korea Department of Radiology Chonnam National University Hospital and Medical SchoolGwangju 61469South Korea Department of Radiology Chonnam National University Hwasun HospitalHwasungun 58128South Korea

BACKGROUND In general,venous aneurysm associated with dural arteriovenous fistula(dAVF)is considered to be developed under long standing venous hypertension and manifested as venous ectasia of draining vein ***,discrete saccular shaped venous aneurysm without angiographic evidence of venous hypertension arising from the draining vein,like cerebral arterial aneurysm,is quite rare and its pathomechanism remains unclear in patients with *** SUMMARY In this report,we present two cases of ruptured saccular venous aneurysms associated with dAVF without venous hypertension or venous *** both cases,significant curve or stenosis is observed in draining vein,which is located in just distal portion of the venous *** aneurysms were successfully treated with a transarterial *** mechanism of venous aneurysms in these cases is *** Although there is little doubt that hemodynamic stress has a critical role in the development of venous aneurysms in patients with dAVF,preceding venous hypertension or venous ectasia is not necessary for development and enlargement of venous *** the significant risk of rupture,a careful review of draining vein features including tortuosity or stenosis is needed,especially in venous aneurysms without evidence of venous hypertension.

关键词： Dural arteriovenous fistula Venous aneurysm Hemodynamic stress Intracranial hemorrhage Embolization Case report

Malignant mesothelioma of the greater omentum mimicking omental infarction:A case report

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World Journal of Gastroenterology 2009年第38期15卷 4856-4859页

作者： Min-kee Shin Ok-Jae Lee chang-Yoon Ha Hyun-joo Min Tae-Hyo Kim Department of Internal Medicine & Institute of Health Science Gyeongsang National University School of Medicine

Mesothelioma develops most commonly in the pleura, and less frequently in the peritoneum. Usually, it manifests as diffuse peritoneal thickening and multiple nodules, and rarely as a solitary mass. We report a rare case of primary malignant mesothelioma of the greater omentum, which mimicked omental infarct. A 54-year-old Korean man was admitted because of severe abdominal pain of sudden onset. A tender mass with indistinct margins was palpated in the upper abdomen. Abdominal ultrasound and computed tomography showed an ill- def ined mass in the greater omentum and little ascites in the peri-hepatic space, and neutrophil-dominant exudates were documented on paracentesis. Intravenous antibiotics and analgesics were given for omental infarction with superimposed infection, which resulted in symptomatic improvement. The imaging studies after a week revealed a growing mass and ascites. Laparoscopic surgery was performed and an 8 cm×3.3 cm greater omental mass was found, with multiple small nodules on the peritoneum, diaphragm, and pelvic cavity wall. Histological examination showed proliferating malignant epithelioid cells that stained strongly for calretinin, which was compatible with malignant mesothelioma. We recommend that primary omental mesothelioma should be included in the differential diagnosis of patients with omental infarction, despite its rarity.

关键词： Infarction Mesothelioma, Omentum

Trace of heat kernel,spectral zeta function and isospectral problem for sub-laplacians

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Science China Mathematics 2009年第12期52卷 2570-2589页

作者： chang Der-Chen YEUNG Sai-kee Department of Mathematics Georgetown University Department of Mathematics Purdue University

In this article, we first study the trace for the heat kernel for the sub-Laplacian operator on the unit sphere in ? n+1. Then we survey some results on the spectral zeta function which is induced by the trace of the ... 详细信息

关键词： sub-Laplacian heat kernel CR-isospectral problem Riemannian zeta function Mellin transform pseudo-hermitian structure Primary: 53C17 Secondary: 34K10, 35H20

Formulation of Reduction Rate for Ultimate Compressive Strength of Stiffened Panel Induced by Opening

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China Ocean Engineering 2014年第4期28卷 557-568页

作者：于昌利 LEE joo-sung School of Naval Architecture and Ocean Engineering Harbin Institute of Technology School of Naval Architecture and Ocean Engineering University of Ulsan

The main objective of this study is to numerically investigate the characteristics of ultimate compressive strength of stiffened panels with opening and also to fit the design-oriented formulae. For this purpose, three series of well executed experimental data on longitudinally stiffened steel plates with and without opening subjected to the uniform axial in-pane load which is carried out to study the buckling and post-buckling up to the final failure are chosen. Also, a nonlinear finite element method capable of efficiently analyzing the large elasto-plastic deflection behavior of stiffened panels is developed and used for simulation. The feasibility of the present simulation process is confirmed by a good agreement with the experimental results. More case studies are developed employing the simulation process to analyze the influence of various design variables on the reduction rate of ultimate strength of stiffened panel induced by opening. Based on the computed results, two design formulae are fitted and the accuracy of design formulae is studied. Furthermore, the viability of the design formulae for practical engineering is proved.

关键词： stiffened panel opening reduction rate non-linear analysis formulae fitting

Application of artificial intelligence in gastroenterology

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World Journal of Gastroenterology 2019年第14期25卷 1666-1683页

作者： Young joo Yang chang Seok Bang Department of Internal Medicine Hallym University College of Medicine

Artificial intelligence(AI) using deep-learning(DL) has emerged as a breakthrough computer technology. By the era of big data, the accumulation of an enormous number of digital images and medical records drove the need for the utilization of AI to efficiently deal with these data, which have become fundamental resources for a machine to learn by itself. Among several DL models, the convolutional neural network showed outstanding performance in image analysis. In the field of gastroenterology, physicians handle large amounts of clinical data and various kinds of image devices such as endoscopy and ultrasound. AI has been applied in gastroenterology in terms of diagnosis,prognosis, and image analysis. However, potential inherent selection bias cannot be excluded in the form of retrospective study. Because overfitting and spectrum bias(class imbalance) have the possibility of overestimating the accuracy,external validation using unused datasets for model development, collected in a way that minimizes the spectrum bias, is mandatory. For robust verification,prospective studies with adequate inclusion/exclusion criteria, which represent the target populations, are needed. DL has its own lack of *** interpretability is important in that it can provide safety measures, help to detect bias, and create social acceptance, further investigations should be performed.

关键词： Artificial intelligence Convolutional neural network Deep-learning Computer-assisted Gastroenterology Endoscopy

Effects of an Urban Park and Residential Area on the Atmospheric CO_2 Concentration and Flux in Seoul,Korea

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Advances in Atmospheric Sciences 2013年第2期30卷 503-514页

作者： Moon-Soo PARK Seung Jin joo chang Seok LEE Center for Atmospheric and Environmental Modeling Seoul 151 919Korea Life and Environmental Engineering Seoul Women's UniversitySeoul 139 774Korea

The CO2 concentrations and fluxes over an urban forest site （Namsan） and an urban residential region （Boramae） in Seoul, Korea, during the non-growing season （2 4 March 2011）, the growing season （10-12 June 2011）, and the late-growing season （22-24 September 2011） were analyzed. The CO2 concentrations of two sites showed nearly the same diurnal variation, with a maximum value occurring during the night and a minimum value occurring during daytime, as well as the same seasonal variation, with a maximum value during the non-growing season （early spring） and a minimum value during the growing season （summer）. The CO2 flux over the urban forest did not show any typical diurnal variation during the non-growing season, but did show diurnal variation with a small positive value during the night and a large negative value during daytime in the growing and late-growing seasons due to photosynthesis in the urban forest. The CO2 flux over the urban residential region showed a positive daily mean value for all periods, with large values during the non-growing season and small values during the growing season, and it also showed diurnal variation with two maxima at 0600-1000 LST and 1800-2400 LST, and two minima at 0300-0600 LST and 1100-1500 LST, and was strongly correlated with the use of liquefied natural gas for cooking and heating by surrounding houses.

关键词： C02 concentration C02 flux Seoul urban forest urban residential region

Direct dynamic-simulation approach to trajectory optimization

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Chinese Journal of Aeronautics 2021年第10期34卷 6-19页

作者： Sung Wook HUR Seong Han LEE Yong Hyeon NAM chang-joo KIM Department of Aerospace Information Engineering Konkuk UniversitySeoul 05029Republic of Korea

This paper proposes a new direct method for an efficient trajectory optimization using the point that the dynamics of a deterministic system are uniquely determined by initial states and controls imposed over the time horizon of *** effectively implement this concept,the Hermite spline is adopted to interpolate the continuous controls and the system dynamics are integrated with corresponding control parameters in *** a result,the optimal control problem can be transcribed into a nonlinear programming problem which has no dynamic equality constraints and no intermediate states in its design *** addition,the paper proposes an efficient recursive Jacobian estimation technique and introduces a Jacobian transformation matrix to straightforwardly handle the general state *** properties of the present method are thoroughly investigated through its applications to the trajectory optimization for a soft lunar landing from a parking orbit,including the detailed analyses for the de-orbiting *** computed results are compared with those using the pseudo-spectral method to demonstrate an extreme outperformance of the proposed method in the aerospace applications over the traditional direct method.

关键词： Trajectory optimization Direct method Hermite spline interpolation Pseudo-spectral integrator Soft lunar landing

Implementation of tactical maneuvers with maneuver libraries

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Chinese Journal of Aeronautics 2020年第1期33卷 255-270页

作者： Do hyeon LEE chang-joo KIM Sung wook HUR Seong han LEE School of Aerospace Information Engineering Konkuk UniversitySeoul 05029Republic of Korea

This study creates and combines the general maneuver libraries for fixed-wing aircraft to implement tactical ***,the generalized maneuver libraries are established by analyzing the characteristics of tactical maneuvers required in *** 7th order polynomial is applied to both the creation of the maneuver libraries and the generation of the trajectories or flight paths for modal *** track the desired trajectory,we design the Attitude Command Attitude Hold(ACAH)system and the Rate Command Rate Hold(RCRH)system using Model Following Controller(MFC).Moreover,the Line-of-Sight(LOS)guidance law is *** particular,the CONDUIT~?is employed to optimize the gains so that the control systems meet the aircraft Handling Qualities(HQ)***,flight simulations are performed for the longitudinal loop,immelmann-turn,and climb-slalom-descent maneuvers to verify that tactical aggressive maneuvers are realizable via the combination of maneuver *** study can contribute to the development of flight techniques for aircraft tactical maneuvers and to the revision of air force operational manuals.

关键词： 7th order polynomial Attitude command attitude hold system Handling qualities Maneuver libraries Rate command rate hold system Tactical maneuvers