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Intraoperative radiofrequency ablation with or without tumorectomy for hepatocellular carcinoma in locations difficult for a percutaneous approach

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Hepatobiliary & Pancreatic Diseases International 2009年第6期8卷 591-596页

作者： Hyung Ook Kim Seung Kwon Kim Byung Ho Son chang hak yoo Hyun Pyo Hong Yong Kyun Cho Byung Ik Kim Departments of Surgery Kangbuk Samsung Hospital Sungkyunkwan University School of Medicine Radiology Kangbuk Samsung Hospital Sungkyunkwan University School of Medicine Division of Interventional Radiology Mallinckrodt Institute of RadiologyWashington University School of Medicine Internal Medicine Kangbuk Samsung Hospital Sungkyunkwan University School of Medicine

BACKGROUND:Although hepatic resection is widely accepted as a proper modality for treating hepatocellular carcinoma(HCC),a majority of patients are unable to undergo surgical resection due to various tumor and patient *** ablation(RFA)has mostly been used as a therapeutic alternative to resection for treating *** objective of this study was to evaluate the results of intraoperative RFA for HCCs in locations difficult for a percutaneous ***:Eight patients(male,seven;age,49-67 years) with 8 HCCs in difficult locations were treated by intraoperative *** of the patients had local tumor progression after initial transarterial chemoembolization or ultrasound(US)guided percutaneous *** locations of the tumors were hepatic dome in six patients,posterior subcapsule in one,and caudate lobe in *** tumor size was 2.0 to 6.4 cm(mean,3.9 cm).Intraoperative RFA was performed at the tumor itself and an anticipated resection line under US guidance with 3 cm monopolar single or clustered internally cooled *** resection was performed in six *** month later,treatment response was assessed by contrast material-enhanced computed tomography(CT).CT studies were performed every 2 or 3 months after ***:RFA was technically successful in all tumors,and the contrast-enhanced CT images acquired one month later showed complete disappearance of tumor *** pneumothorax *** a median follow-up of 18 months(range,6-30 months),no tumors showed local *** the follow-up period,four new recurrent tumors were observed in three *** patients were alive at the time of this report and the other four died of hepatorenal syndrome,liver failure,and progression of new recurrent ***:Intraoperative RFA with tumor resection can be an alterative treatment option for HCC in locations difficult for a percutaneous approach.

关键词： hepatocellular carcinoma radiofrequency ablation intraoperative

Outcome of laparoscopic cholecystectomy is not influenced by chronological age in the elderly

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World Journal of Gastroenterology 2009年第6期15卷 722-726页

作者： Hyung Ook Kim Jung Won Yun Jun Ho Shin Sang Il Hwang Yong Kyun Cho Byung Ho Son chang hak yoo Yong Lai Park Hungdai Kim Departments of Surgery Kangbuk Samsung Hospital Sungkyunkwan University School of MedicineSeoul 110-746 South Korea Departments of Internal Medicine Kangbuk Samsung HospitalSungkyunkwan University School of MedicineSeoul 110-746South Korea

AIM:To evaluate the outcome of laparoscopic cholecystectomy(LC)in patients aged 80 years and older. METHODS:A total of 353 patients aged 65 to 79 years(group 1)and 35 patients aged 80 years and older(group 2)underwent *** were further classified into two other groups:those with uncomplicated gallbladder disease(group A)or those with complicated gallbladder disease(group B). RESULTS:There were no significant differences between the age groups(groups 1 and 2)with respect to clinical characteristics such as age,gender,comorbid disease,or disease *** operative time,conversion rate,and the incidence of major postoperative complications were similar in groups 1 and ***,the percentage of high-risk patients was significantly higher in group 2 than in group 1 (20.0%vs 5.7%,P<0.01).Group A comprised 322 patients with a mean age of 71.0±5.3 years,and group B comprised 51 patients with a mean age of 69.9±4.8 *** group B,mean operative time (78.4±49.3 min vs 58.3±35.8 min,P<0.01),mean postoperative hospital stay(7.9±6.5 d vs 5.0±3.7 d, P<0.01),and the incidence of major postoperative complications(9.8%vs 3.1%,P<0.05)were significantly greater than in group *** conversion rate tended to be higher in group B,but this difference was not significant. CONCLUSION:Perioperative outcomes in elderly patients who underwent LC seem to be influenced by the severity of gallbladder disease,and not by chronologic *** octogenarians,LC should be performed at an earlier,uncomplicated stage of the disease whenever possible to improve perioperative outcomes.

关键词： Elderly Laparoscopic cholecystectomy Octogenarians Gallbladder Cholecystitis

Surface doping effect on the optoelectronic performance of 2D organic crystals based on cyano-substituted perylene diimides

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Chinese Chemical Letters 2024年第9期35卷 193-197页

作者： Jaeyong Ahn Zhenping Li Zhiwei Wang Ke Gao Huagui Zhuo Wanuk Choi Gang chang Xiaobo Shang Joon hak Oh School of Chemical and Biological Engineering Institute of Chemical ProcessesSeoul National UniversitySeoul 08826South Korea State Key Laboratory for Mechanical Behavior of Materials Shaanxi International Research Center for Soft MatterSchool of Materials Science and EngineeringXi’an Jiaotong UniversityXi’an 710049China Center for Ordered Nanoporous Materials Synthesis School of Environmental Science and EngineeringPohang University of Science and TechnologyGyeongbuk 37673South Korea Instrumental Analysis Center of Xi’an Jiaotong University Xi’an 710049China

Compared to organic thin films,organic single crystals offer significant potential in organic phototransistors(OPTs)due to their enhanced charge transport,large surface area,and defect-free ***,the development of n-type semiconductors has lagged behind p-type *** enhance semiconductor device performance,a doping process can be employed,which typically involves the introduction of charged impurities into the crystalline semiconducting *** aim is to reduce the Ohmic losses,increase carrier density,improve transport capabilities,and facilitate effective carrier injection,ultimately enhancing the electrical properties of the *** doping processes,however,often pose a risk of damaging the structure of single *** this study,we have synthesized novel cyanosubstituted chiral perylene diimides,which self-assemble into two-dimensional single crystals that can be used for n-type semiconductor *** have employed a surface doping strategy using diethylamine vapor without disrupting the crystal *** fabricated devices exhibit significantly higher charge transport properties after doping,achieving a maximum electron mobility of 0.14 cm^(2)V^(-1)s^(-1),representing an improvement of over ***,the optoelectronic performance of the doped devices has significantly improved,with the external quantum efficiency increased by over 9 times and the significantly improved response *** results suggest that our surface doping technology is a promising way for enhancing the performance of 2D organic single-crystal OPTs.

关键词： Doping effect Phototransistors Perylene diimides Organic crystals Cyano substitution

Surface effects of hybrid vibration-assisted femtosecond laser system for micro-hole drilling of copper substrate

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中国有色金属学会会刊：英文版 2012年第S3期22卷 801-807页

作者： Jung-Kyu PARK Ji-Woon yooN Myung-chang KANG Sung-hak CHO Nano Machining Laboratory Korea Institute of Machinery and Materials Department of Nano-Mechatronics University of Science and Technology National Core Research Center for Hybrid Materials Solution Pusan National University

The ultrafast laser based hybrid machining system was studied and a novel approach was demonstrated to improve laser machining quality on metals by vibrating the optical objective lens with a low frequency (500 Hz) and various displacements (0-16.5 μm) during a femtosecond laser machining *** laser used in this experiment is an amplified Ti:sapphire femtosecond (10-15 s) laser system that generates 100 femtosecond pulses having an energy of 3.5 mJ/pulse with a 5 kHz repetition rate at a central wavelength of 790 *** is found that both the wall surface finish of the machined structures and the aspect ratio obtained using the frequency vibration assisted laser machining are improved compared with those derived via laser machining without vibration assistance.

关键词： femtosecond laser hybrid machining vibration-assisted machining surface roughness aspect ratio

Real-Time Demand Response Management for Controlling Load Using Deep Reinforcement Learning

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Computers, Materials & Continua 2022年第12期73卷 5671-5686页

作者： Yongjiang Zhao Jae Hung yoo chang Gyoon Lim Department of Computer Engineering Chonnam National UniversityYeosu59626Korea

With the rapid economic growth and improved living standards,electricity has become an indispensable energy source in our ***,the stability of the grid power supply and the conservation of electricity is *** following are some of the problems facing now:1)During the peak power consumption period,it will pose a threat to the power *** and improving the power distribution infrastructure requires high maintenance costs.2)The user’s electricity schedule is unreasonable due to personal behavior,which will cause a waste of *** load as a vital part of incentive demand response(DR)can achieve rapid response and improve demand-side *** load by manually formulating rules,some devices are selective to be adjusted during peak power ***,it is challenging to optimize methods based on manual *** paper uses SoftActor-Critic(SAC)as a control algorithm to optimize the control *** results show that through the coordination of the SAC to control load in CityLearn,realizes the goal of reducing both the peak load demand and the operation costs on the premise of regulating voltage to the safe limit.

关键词： Demand response controlling load SAC CityLearn

Sensitivity evaluation of the flash flood warning system introduced to ungauged small mountainous basins in Korea

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Journal of Mountain Science 2019年第5期16卷 971-993页

作者： yoo Chulsang LEE Jinwook chang Kwonhee YANG Dongmin School of Civil Environmental and Architectural Engineering College of Engineering Korea University NOAA SNC Co. Ltd.

This study evaluates the uncertainty involved in the determination of the flash flood guidance(FFG) of the flash flood warning system(FFWS) for a small mountainous region(FFWS_MR)in Korea. The sensitivity is evaluated both at each step to determine the FFG and for all steps together. The results show that the relative difference of the FFG is about 50% of the current system, most of which involves the channel width. Especially, the use of some specific empirical equations to estimate the major parameters results in a considerable amount of the relative difference of the FFG. In addition, though only four basins were field-surveyed, it is found that the indirect estimation of the major parameters always introduces some amount of additional uncertainty. In conclusion, accurate estimation of the major parameters must be the most important procedure to derive an accurate FFG, among which the channel cross-section at the exit of the basin lies at the center.

关键词： Flash flood warning system Flash flood guidance Sensitivity analysis

Nonlinear Optical Properties in a Quantum Dot of Some Polar Semiconductors

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Chinese Physics Letters 2013年第10期30卷 147-151页

作者： A.Azhagu Parvathi A.John Peter chang Kyoo yoo Department of Physics VV Vanniaperumal College for WomenVirudhunagar-626001India Department of Physics Govt.Arts and Science CollegeMelur-625106MaduraiIndia Center for Environmental Studies/Green Energy Center Department of Environmental Science and EngineeringCollege of EngineeringKyung Hee UniversitySeocheon-dong 1Giheung-guYongin-SiGyeonggi-Do 446-701South Korea

Exciton binding energy,interband emission energy,oscillator strength,and some nonlinear optical properties in quantum dots made up of polar semiconductors are computed with the geometrical *** effects of the interaction of charge carriers with the longitudinal optical phonons on the exciton binding energy are *** anisotropy of the effective masses of holes is incorporated throughout the *** optical exciton absorption of Ⅱ–Ⅵ systems based on some polar semiconductors in the presence of LO phonons is *** optical rectification coefficient associated with the intersubband transitions in a quantum dot of polar semiconductors is *** of refractive index with the photon energy in a polar quantum dot are *** results show that the polar bound excitons in Ⅱ–Ⅵ based polar semiconductors depend on the geometrical confinement,and the nonlinear optical properties strongly depend on the polar materials.

关键词： materials Nonlinear semiconductors

A Novel Goodness of Fit Test Spectrum Sensing Using Extreme Eigenvalues

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Chinese Journal of Electronics 2020年第6期29卷 1201-1206页

作者： LI He ZHAO Wenjing LIU chang JIN Minglu yoo Sang-Jo School of Information and Communication Engineering Dalian University of Technology Department of Information and Communication Engineering Inha University

The existing Goodness of fit(GoF) test based spectrum sensing algorithms mostly use samples or energies as observations to make decisions,which can hardly achieve satisfactory performance especially when the Primary user(PU) signals are highly ***,the eigenvalue of covariance matrix can reflect signal correlations *** by this,we study the distribution of eigenvalue and propose an eigenvalue based GoF spectrum sensing *** the proposed scheme,we use the ratios of maximum to minimum eigenvalue as observations and thus it can bring performance improvements through capturing correlation of PU *** also provide the related theoretical analysis for the proposed *** results show that the proposed method overcomes the problem of noise uncertainty and achieves performance improvement over the classical samples-based GoF test.

关键词： eigenvalue based GoF spectrum sensing algorithm GoF test based spectrum sensing algorithm primary user signal covariance matrix eigenvalue Radio links and equipment eigenvalues and eigenfunctions signal detection Algebra goodness of fit test spectrum sensing algorithm Linear algebra (numerical analysis) signal sampling signal denoising radio spectrum management correlation methods covariance matrices Signal detection signal correlation

Optical diffraction gratings embedded in BK-7 glass by low-density plasma formation using femtosecond laser

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Transactions of Nonferrous Metals Society of China 2011年第A1期21卷 165-169页

作者： Jung-Kyu PARK Sung-hak CHO Kwang-Ho KIM Myung-chang KANG Nano Machining Laboratory Korea Institute of Machinery and Material Daejeon 305-343 Korea National Core Research Center for Hybrid Materials Solution Pusan National University

The optical embedded diffraction gratings with the internal refractive index modification in BK-7 glass plates were demonstrated using low-density plasma formation excited by a high-intensity femtosecond （130 fs） Ti： sapphire laser （λp=790 rim）. The refractive index modifications with diameters ranging from 400 nm to 4 gm were photoinduced after plasma formation occurred upon irradiation with peak intensities of more than 1 ×10^13 W/cm2. The graded refractive index profile was fabricated to be a symmetric around the center of the point at which low-density plasma occurred. The maximum refractive index change （An） was estimated to be 1.5x10 2. Several optical embedded gratings in BK-7 glass plate were demonstrated with refractive index modification induced by the scanning of low-density plasma formation.

关键词： BK-7 glass plate diffraction grating refractive index modification plasma formation femtosecond laser