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Precipitate Contribution to the Acoustic Nonlinearity in Nickel-Based Superalloy

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Chinese Physics Letters 2009年第8期26卷 219-222页

作者： Chung-seok KIM Cliff J. LISSENDEN Engineering Science and Mechanics The Pennsylvania State University 212 EES Bldg. University Park PA 16802 USA

The influence of γ′ precipitate on the acoustic nonlinearity is investigated for a nickel-based superalloy, which is subjected to creep deformation. During creep deformation, the cuboidal γ′ precipitate is preferentially coarsened in a direction perpendicular to the applied stress axis. The length and shape factor of the γ′ precipitate increase with creep time. The increase of relative acoustic nonlinearity with increasing fraction of creep life is discussed in relation to the rafting of γ′ precipitate, which is closely related to the scattering and distortion of the acoustic wave

关键词： PRECIPITATION (Chemistry) NONLINEAR acoustics NICKEL alloys HEAT resistant alloys CREEP (Materials) DEFORMATIONS (Mechanics) SOUND wave scattering

Enhancement in Light Extraction Efficiency of GaN-Based Light-Emitting Diodes Using Double Dielectric Surface Passivation

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Optics and Photonics Journal 2012年第3期2卷 185-192页

作者： Chung-Mo Yang Dong-seok Kim Yun Soo park Jae-Hoon Lee Yong Soo Lee Jung-Hee Lee GaN Power Research Group R&D Institute Samsung LED Co. Ltd Suwon Republic of Korea School of Electrical Engineering and Computer Science Kyungpook National University Daegu Republic of Korea

SiO2Al2O3 double dielectric stack layer was deposited on the surface of the GaN-based light-emitting diode (LED). The double dielectric stack layer enhances both the electrical characteristics and the optical output power of the LED because the first Al2O3 layer plays a role of effectively passivating the p-GaN surface and the second lower index SiO2 layer increases the critical angle of the light emitted from the LED surface. In addition, the effect of the Fresnel reflection is also responsible for the enhancement in output power of the double dielectric passivated LED. The leakage current of the LED passivated with Al2O3 layer was -3.46 × 10-11 A at -5 V, at least two and three orders lower in magnitude compared to that passivated with SiO2 layer (-7.14 × 10-9 A) and that of non-passivated LED (-1.9 × 10-8 A), respectively, which indicates that the Al2O3 layer is very effective in passivating the exposed GaN surface after dry etch and hence reduces nonradiative recombination as well as reabsorption of the emitted light near the etched surface.

关键词： GaN Light-Emitting Diode (LED) Al2O3 PEALD Passivation Double Dielectric Stack Layer

Optimum traveling and rotation speeds in friction stir welding for dissimilar Al alloys

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Transactions of Nonferrous Metals Society of China 2011年第7期21卷 1486-1490页

作者： Jae-Cheul park Min-Su HAN seok-Ki JANG Seong-Jong KIM Division of Marine System Engineering Mokpo Maritime UniversityMokpo CityJeonnam530-729Korea

Aluminum alloys are subjected to large deformation and decreased strength due to the high expansion modulus caused by heat effects during friction stir welding （FSW）.The optimum conditions for friction stir welding of 5052-O and 6061-T6 Al alloys were *** optimum traveling and rotation speeds were identified to be 61mm/min and 1600r/min using various mechanical characteristic evaluation methods.

关键词： Al alloy friction stir welding (FSW) traveling speed rotation speed mechanical property

Understanding of Ultrasonic Assisted Machining with Diamond Grinding Tool

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Modern Mechanical Engineering 2014年第1期4卷 1-7页

作者： Kyung-Hee park Yun-Hyuck Hong Kyeong-Tae Kim seok-Woo Lee Hon-Zong Choi Young-Jae Choi Korea Institute on Industrial Technology Chungcheong Regional Division Cheonan-si South Korea Korea Institute on Industrial Technology Future Manufacturing System R&D Group Manufacturing System R&D Department Cheonan-si South Korea Korea Institute on Industrial Technology IT Converged Process R&D Group Convergent Technology R&D Department Ansan-si South Korea

In this work, machining test was carried out in various machining conditions using ultrasonic vibration capable CNC machine. For work material, alumina ceramic (Al2O3) was used while for tool material diamond electroplated grinding wheel was used. To evaluate ultrasonic vibration effect, grinding test was performed with and without ultrasonic vibration in same machining condition. In ultrasonic mode, ultrasonic vibration of 20 kHz was generated by HSK 63 ultrasonic actuator. On the other hand, grinding forces were measured by KISTLER dynamometer. And an optimal sampling rate for grinding force measurement was obtained by a signal processing and frequency analysis. The surface roughness of the ceramic was also measured by using stylus type surface roughness instrument and atomic force microscope (AFM). Besides, the scanning electron microscope (SEM) was used for observation of surface integrality.

关键词： Ultrasonic Vibration Grinding Alumina Ceramic Grinding Forces Surface Roughness

Analysis on sports and recreation activity-related eye injuries presenting to the Emergency Department

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International Journal of Ophthalmology(English edition) 2016年第10期9卷 1499-1505页

作者： Sungbae Moon Hyun Wook Ryoo Jae Yun Ahn Jung Bae park Kang Suk Seo Sang Do Shin Kyoung Jun Song Kang Hyun Lee In Sool Yoo Jin Seong Cho Hyun Ho Ryu Tae Oh Jeong seok Ran Yeom Young Taek Kim Sung Ok Hong Department of Emergency Medicine School of MedicineKyungpook National University Daegu 700-721 Korea Department of Emergency Medicine College of MedicineSeoul National University Seoul 110-799 Korea Department of Emergency Medicine Wonju College of Medicine Yonsei University Wonju Gangwon-do 220-701Korea Department of Emergency Medicine School of MedicineChungnam National University Daejeon 301-747 Korea Department of Emergency Medicine Gachon University Gil Medical Center Incheon 406-799 Korea Department of Emergency Medicine School of MedicineChonnam National University Gwangju 501-746 Korea Department of Emergency Medicine School of MedicineChonbuk National University Jeonju Jeollabuk-do 561-180Korea Department of Emergency Medicine School of MedicinePusan National University Busan 602-739 Korea Korean Centers for Disease Control & Prevention Cheongiu Chungcheongbuk-do 361-951 Korea

AIM：To investigate the incidence and general characteristics of sports-related eye injuries in patients visiting the Emergency Department. METHODS： A cross-sectional,multi-center,observational *** with an injured eye who visited the Emergency Department at one of nine hospitals in Korea were *** data were prospectively collected between March and September 2010 using a *** injuries that occurred during risky sports were examined by gender and ***,the rate of open globe injuries that occurred with and without protective eyewear was examined for each *** variables were compared using Student＇s t-test and categorical variables were compared using Chi-square ***： A total of 446 patients had sports-related eye ***（10-19 years old） and young adults（20-29 years old） had the most eye *** injuries accounted for 0.2% of Emergency Department *** was the most common cause of sports-related eye injuries,followed by soccer and *** gear was worn by 9.4% of all *** that were 30-39 years of age had the highest rate of protective gear use,followed by patients that were 40-49 years of *** proportion of sports-related eye injuries that were open-globe injuries was highest for soccer and ***： Although injuries were most common in patients below the age of 10 years,these patients had the lowest rate of protective eyewear *** in adults over 40 years of age most commonly occurred during hiking,but the rate of protective eyewear use was *** athletes should be educated on and provided with protective eyewear and policies protective gear use should be *** older adults,eye protection should be encouraged,especially during hiking.

关键词： athletic injuries eye injuries protective devices sports.

Role of human glioma stroma mesenchymal stem cells in human glioma

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Role of human glioma stroma mesenchymal stem cells in human ...

Gastrointestinal stromal tumor solitary distant recurrence in the left brachialis muscle

中国抗癌协会神经肿瘤专业委员会第八届学术会议

作者： seok-Gu Kang Hyun-Su Mok Hyun-Do Shin Yoon-Kyung park Na-Ri park Youn Soo Lee YongKil Hong Department of Neurosurgery The Catholic University of Korea College of MedicineSeoul St.Mary's Hospital

Object We have proved that the existence of glioma stroma mesenchymal stem cells（GS-MSCs）,which are one of components of glioma ***-MSCs may represent non-neural stem cells that act as an important source of mesenchymal elements,particularly during the growth of *** tried to investigate the biological effect of GS-MSCs on glioma cancer stem cells（gCSCs）.We hypothesized that GS-MSCs increase the proliferation of *** We could isolate human GS-MSCs and human gCSCs from human glioma *** gCSCs were co-cultured with human *** vitro proliferation characteristics were evaluated between gCSCs alone and gCSCs co-cultured with *** also investigated the changes of gCSCs protein before and after GS-MSCs *** we created mouse orthotopic glioma xenograft with gCSCs and gCSCs after coculturing with *** analyzed the survival,tumor volume,vessel formation,and proliferation about mouse orthotopic glioma xenografts between two groups（gCSCs alone and gCSCs after co-culturing with GSMSCs） by immunofluorescent *** After gCSCs were co-cultured with GS-MSCs,proliferation activity of gCSCs increased 4 times more than gCSCs *** Akt pathway related protein expression was increased when gCSCs were co-cultured with *** co-culturing gCSCs with GS-MSCs,tumor volume,PCNA expression,and vessel density were increased and survival time was *** together,GS-MSCs change biological characteristics of gCSCs to become more aggressive *** Our results indicated that GS-MSCs are able to change biological characteristics of gCSCs to become more aggressive *** the first time,we have successfully proved the biological effect of human GSMSCs on human gCSCs in vitro and in ***-MSCs may represent non-neural stem cells that act as an important source of mesenchymal elements,particularly during the growth of gliomas.

关键词： glioma glioma cancer stem cells mesenchymal stem cells proliferation stroma cells survival

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World Journal of Gastroenterology 2015年第20期21卷 6404-6408页

作者： Su-Sin Jin Hyeong-seok Jeong Hyun-Jin Noh Woo-Hyung Choi Seung-Hwa Choi Kang-Yeon won Dong-Pil Kim Ji-Chan park Mi-Kyong Joung Jeong-Goo Kim Hae-Joung Sul Seung-Woo Lee Division of Gastroenterology Department of Internal MedicineDaejeon St.Mary’s HospitalThe Catholic University of Korea Department of Internal Medicine Anyang Sam Hospital Department of General Surgery Daejeon St.Mary’s HospitalThe Catholic University of Korea Department of Pathology Daejeon St.Mary’s HospitalThe Catholic University of Korea

Gastrointestinal stromal tumors(GISTs) are mesenchymal tumors of the gastrointestinal tract that are most commonly found in the stomach. Although GISTs can spread to the liver and peritoneum, metastasis to the skeletal muscle is very rare and only four cases have previously been reported. These cases involved concurrent skeletal metastases of primary GISTs or liver metastases. Here, we report the first case of a distant recurrence in the brachialis muscle after complete remission of an extra-luminal gastric GIST following a wedge resection of the stomach, omental excision, and adjuvant imatinib therapy for one year. Ten months after therapy completion, the patient presented with swelling and tenderness in the left arm. Magnetic resonance imaging revealed a large mass in the brachialis muscle, which showed positivity for c-kit and CD34 upon pathologic examination. This is the first reported case of a solitary distant recurrence of a GIST in the muscle after complete remission had been achieved.

关键词： Brachialis muscle Distant recurrence Gastrointestinal stromal tumor Skeletal metastasis Tyrosine kinase inhibitor

Advantage of endoscopic mucosal resection with a cap for rectal neuroendocrine tumors

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World Journal of Gastroenterology 2015年第31期21卷 9387-9393页

作者： Su Bum park Hyung Wook Kim Dae Hwan Kang Cheol Woong Choi Su Jin Kim Hyeong seok Nam Department of Internal Medicine Pusan National University School of Medicine Research institute for Convergence of Biomedical Science and Technology Pusan National University Yangsan Hospital

AIM: To compare the outcomes of endoscopic mucosal resection with a cap(EMR-C) with those of endoscopic submucosal dissection(ESD) for the resection of rectal neuroendocrine ***: One hundred and sixteen lesions in 114 patients with rectal neuroendocrine tumor(NET) resected with EMR-C or ESD were included in the study. This study was performed at Pusan National University Yangsan Hospital between July 2009 and August 2014. We analyzed endoscopic complete resection rate,pathologic complete resection rate,procedure time,and adverse events in the EMR-C(n = 65) and ESD(n = 51) groups. We also performed a subgroup analysis by tumor ***: Mean tumor size was 4.62 ± 1.66 mm in the EMR-C group and 7.73 ± 3.14 mm in the ESD group(P < 0.001). Endoscopic complete resection rate was 100% in both groups. Histologic complete resection rate was significantly greater in the EMR-C group(92.3%) than in the ESD group(78.4%)(P = 0.042). Mean procedure time was significantly longer in the ESD group(14.43 ± 7.26 min) than in the EMR-C group(3.83 ± 1.17 min)(P < 0.001). Rates of histologic complete resection without complication were similar for tumor diameter ≤ 5 mm(EMR-C,96%; ESD,100%,P = 0.472) as well as in cases of 5 mm < tumor diameter ≤ 10 mm(EMR-C,80%; ESD,71.0%,P = 0.524).CONCLUSION: EMR-C may be simple,faster,and more effective than ESD in removing rectal NETs and may be preferable for resection of small rectal NETs.

关键词： Neuroendocrine tumor Endoscopic mucosal resection

Development of a high cycle fatigue testing system and its application to thin aluminum film

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Development of a high cycle fatigue testing system and its a...