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Fatigue strength evaluation of self-piercing riveted joints of AZ31 Mg alloy and cold-rolled steel sheets

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Journal of Magnesium and Alloys 2020年第1期8卷 241-251页

作者： Se-Hyung Kang Dong-Woon Han ho-kyung kim Graduate School Seoul National University of Science and TechnologySeoul01811South Korea Department of Mechanical and Automotive Engineering Seoul National University of Science and TechnologySeoul01811 South Korea

The application of magnesium alloys to automobiles is increasing due to their superior specific strength and specific *** this study,an upper sheet of AZ31 magnesium alloy and a lower sheet of cold-rolled steel were joined by self-piercing riveting(SPR),a method commonly used to join automotive panels.A cross-shaped specimen was fabricated with a punching force of 35 kN,which exhibited the best joint strength for the SPR joint specimen *** and fatigue strengths were evaluated using cross-shaped specimens at loading angles of 0°,45°,and 90°.The load amplitude corresponding to the fatigue endurance limit was assumed to be at 106 cycles,and the fatigue ratios(=fatigue endurance limit/static strength)at the loading angles of 0°,45°,and 90°are 22%,13%,and 9%,*** all three loading angle specimens,fatigue cracks initiated at the triple point where the rivet shank,the upper sheet and the lower sheet are in contact with each other,with the cracks propagating through the thickness of the upper sheet and ultimately leading to *** fatigue lifetimes were evaluated through the von-Mises stress,maximum principal stress,and equivalent stress intensity *** was found that the fatigue lifetimes could be evaluated most appropriately through the maximum principal stress.

关键词： Self-piercing riveting Magnesium alloy Fatigue strength Maximum principal stress Fatigue lifetime

Inhibitory Effect of the Extract of Phellodendron amurense Ruprecht Root on Collagen-Induced Arthritis in Mice

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Chinese Journal of Integrative Medicine 2017年第10期23卷 755-762页

作者： Hyo Won Jung kyung-ho kim Yong-Ki Park Department of Herbology College of Korean Medicine Dongguk University Gyeongju (740-814) Republic of Korea Korean Medicine Research and Development Center Dongguk University Gyeongju (740-814) Republic of Korea Department of Acupuncture College of Korean Medicine Dongguk University Gyeongju (740-814) Republic of Korea

Objective： To investigate whether the dried root of Phellodendron amurense Ruprecht（Phellodendri cortex; PC） extract improves arthritic symptoms through anti-inflammatory and immune-modulatory effects in collagen-induced arthritis in mice. Methods： Rheumatoid arthritis（RA） was induced in male DBA/1 mice by immunization with type Ⅱ collagen（ColⅡ）. CIA mice were divided into 5 groups（n=10 per a group） with normal, CIA control, PC extract（50 mg/kg and 100 mg/kg）-treated, and meloxicam（50 mg/kg）-treated as the reference drug. The PC extract or meloxicam were administered orally in CIA mice once a day for 14 days after arthritis induction. Arthritic score, levels of anti-ColⅡ IgG2a antibody, prostaglandin E2（PGE2）, tumor necrosis factor（TNF）-α, and interleukin（IL）-17 in the sera of CIA mice were measured. Histopathological changes in the ankle joints of CIA mice were also analyzed by staining with hematoxylin and eosin（H and E）, safranin-O and immunohistochemistry using anti-TNF-α and anti-IL-17 antibodies. Results： The arthritic score was increased in CIA mice in a time-dependent manner, as were the serum levels of anti-ColⅡ IgG2a antibody, PGE2, TNF-α, and IL-17. however, the oral administration of PC extract at 50 and 100 mg/kg in CIA mice significantly decreased the arthritic scores, and the serum levels of anti-ColⅡ IgG2a, PGE2, TNF-α, and IL-17 compared with those in the CIA group（P〈0.05 or P〈0.01）. Furthermore, histopathological improvement of the joint architecture in CIA mice was observed after administration of PC extract. PC extract also significantly inhibited the expression of TNF-α and IL-17 in the joints of CIA mice by suppressing the expression of their m RNA and proteins. Conclusion： PC extract may improve the pathological progression of RA through the inhibition of joint destruction by synovial inflammation and immune-stimulation, therefore, it would be a potential anti-arthritic agent in RA.

关键词： Phellodendron amurense Phellodendri cortex collagen-induced arthritis anti-arthritic effect

Damping Identification of Bridges Under Nonstationary Ambient Vibration

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Engineering 2017年第6期3卷 839-844页

作者： Sunjoong kim ho-kyung kim Department of Civil and Environmental Engineering Seoul National University Seoul 08826 Korea

This research focuses on identifying the damping ratio of bridges using nonstationary ambient vibration data. The damping ratios of bridges in service have generally been identified using operational modal analysis （OMA） based on a stationary white noise assumption for input signals. however, most bridges are generally subjected to nonstationary excitations while in service, and this violation of the basic assumption can lead to uncertainties in damping identification. To deal with nonstationarity, an amplitude-modulating function was calculated from measured responses to eliminate global trends caused by nonstationary input. A natural excitation technique （NExT）-eigensystem realization algorithm （ERA） was applied to estimate the damping ratio for a stationarized process. To improve the accuracy of OMA-based damping estimates, a comparative analysis was performed between an extracted stationary process and nonstationary data to assess the effect of eliminating nonstationarity. The mean value and standard deviation of the damping ratio for the first vertical mode decreased after signal stationarization.

关键词： Damping Operational modal analysis Traffic-induced vibration Nonstationary Signal stationarization Amplitude-modulating Bridge Cable-stayed Suspension

Influence of FeO and sulfur on solid state reaction between MnO-SiO_2-FeO oxides and an Fe-Mn-Si solid alloy during heat treatment at 1473 K

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International Journal of Minerals,Metallurgy and Materials 2015年第8期22卷 811-819页

作者： Cheng-song Liu Shu-feng Yang kyung-ho kim Jing-she Li Hiroyuki Shibata Shin-ya Kitamura School of Metallurgical and Ecological Engineering University of Science and Technology Beijing Institute of Multidisciplinary Research for Advanced Materials Tohoku University

To clarify the influence of Fe O and sulfur on solid state reaction between an Fe-Mn-Si alloy and Mn O-Si O2-Fe O oxides under the restricted oxygen diffusion flux, two diffusion couples with different sulfur contents in the oxides were produced and investigated after heat treatment at 1473 K. The experimental results were also compared with previous work in which the oxides contained higher Fe O. It was found that although the Fe O content in the oxides decreased from 3wt% to 1wt% which was lower than the content corresponding to the equilibrium with molten steel at 1873 K, excess oxygen still diffused from the oxides to solid steel during heat treatment at 1473 K and formed oxide particles. In addition, increasing the sulfur content in the oxides was observed to suppress the diffusion of oxygen between the alloy and the oxides.

关键词： refining solid state reactions heat treatment incl

Soleus arthrogenic muscle inhibition following acute lateral ankle sprain correlates with symptoms and ankle disability but not with postural control

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Journal of Sport and Health Science 2024年第4期13卷 559-568,F0003页

作者： kyung-Min kim Joo-Sung kim Alan R.Needle Department of Sport Science Sungkyunkwan UniversitySuwon-si 16419Republic of Korea Department of Health and Human Performance Texas State UniversitySan MarcosTX 78666USA Department of Public Health&Exercise Science Appalachian State UniversityBooneNC 28608USA Department of Rehabilitation Science Appalachian State UniversityBooneNC 28608USA

Background:Acute lateral ankle sprains(ALAS)are associated with long-term impairments and instability tied to altered neural *** muscle inhibition(AMI)has been observed in this population;however,relationships with injury-related impairments are unclear,potentially due to the resting,prone position in which AMI is typically *** AMI during bipedal stance may provide a better understanding of this ***:AMI was assessed in 38 young adults(19 ALAS within 72 h of injury:10 males,21.4±2.7 years;19 healthy controls:10 males,21.9±2.2 years;mean±SD)using the hoffmann reflex(H-reflex)during bipedal *** stimulation was administered to identify the _(max)imal H-reflex(H_(max))and _(max)imal motor response(M_(max))from the soleus,fibularis longus,and tibialis anterior *** primary outcome measure was the H_(max)/M_(max) *** outcomes included acute symptoms(pain and swelling),postural control during bipedal stance,and self-reported ***:No significant group-by-limb interactions were observed for any ***,a significant group main effect was observed in the soleus muscle(F(1,35)=6.82,p=0.013),indicating significantly lower H_(max)/M_(max) ratios following ALAS(0.38±0.20)compared to healthy controls(0.53±0.16).Furthermore,lower H_(max)/M_(max) ratios in the soleus significantly correlated with acute symptoms and self-reported function but not with postural ***:This study supports previous evidence of AMI in patients with ALAS,providing insight into neurophysiologic impacts of musculoskeletal *** results suggest that assessing AMI in a standing position following acute injury may provide valuable insight into how AMI develops and guide potential therapeutic options to curb and offset the formation of joint instability.

关键词： Acute injuries Balance hoffmann reflex Neural excitability Patient-reported outcomes

Experience of primary intestinal lymphangiectasia in adults: Twelve case series from a tertiary referral hospital

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World Journal of Clinical Cases 2024年第4期12卷 746-757页

作者： Ji Eun Na Ji Eun kim Sujin Park Eun Ran kim Sung Noh hong Young-ho kim Dong kyung Chang Department of Internal Medicine Inje University Haeundae Paik HospitalBusan 48108South Korea Department of Medicine Samsung Medical CenterSeoul 06351South Korea Department of Pathology Samsung Medical CenterSeoul 06351South Korea

BACKGROUND While primary intestinal lymphangiectasia(PIL)is considered a rare condition,there have been several reported cases in ***,the absence of clear guidance from diagnosis to treatment and prognosis poses challenges for both physicians and *** To enhance understanding by investigating clinical presentation,diagnosis,treatment,complications,and prognoses in adult PIL *** We enrolled adult patients diagnosed with PIL between March 2016 and September *** primary outcome involved examining the diagnosis and treatment process of these *** secondary outcomes included identifying complications(infections,thromboembolism)and assessing prognoses(frequency of hospitalization and mortality)during the follow-up *** Among the 12 included patients,peripheral edema(100%)and diarrhea(75%)were the main presenting *** tests showed that all the pati-ents exhibited symptoms of hypoalbuminemia and ***,the predominant findings were edema of the small intestine(67%)and ascites(58%).The typical endoscopic finding with a snowflake appearance was observed in 75%of *** the 12 patients,two responded positive-ly to octreotide and sirolimus,and eight who could undergo maintenance therapy discontinued *** due to PIL led to infection in half of the patients,thromboembolism in three patients,and one *** PIL can be diagnosed in adults across various age groups,with different severity and treatment responses among patients,leading to diverse complications and ***,tailored treatments will be *** anticipate that our findings will contribute to the management of PIL,an etiology of protein-losing enteropathy.

关键词： Primary intestinal lymphangiectasia in adults Protein-losing enteropathy Diagnosis Treatment Prognosis

Data driven computational design of stable oxygen evolution catalysts by DFT and machine learning:Promising electrocatalysts

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Journal of Energy Chemistry 2024年第4期91卷 645-655页

作者： Hwanyeol Park Yunseok kim Seulwon Choi ho Jun kim Department of Display Materials Engineering Soonchunhyang UniversityAsanChung-nam 31538Republic of Korea Department of Electronic Materials Devicesand Equipment EngineeringSoonchunhyang Uni-versityAsanChungnam 31538Republic of Korea Department of Mechanical Engineering Hanyang University ERICA Campus55 Hanyangdaehak-roSangnok-guAnsanGyeonggi-do 15588Republic of Korea

The revolutionary development of machine learning(ML),data science,and analytics,coupled with its application in material science,stands as a significant milestone of the scientific community over the last *** active,stable,and cost-efficient catalysts is crucial for oxygen evolution reaction owing to the significance in a range of electrochemical energy co nversion *** this work,we have demonstrated an efficient approach of high-throughput screening to find stable transition metal oxides under acid condition for high-performance oxygen evolution reaction(OER)catalysts through density functional theory(DFT)calculation and a machine learning algorithm.A methodology utilizing both the Materials Project database and DFT calculations was introduced to assess the acid stability under specific reaction *** upon this,OER catalytic activity of acid-stable materials was examined,highlighting potential OER catalysts that meet the required *** identified IrO_(2),Fe(SbO_(3))_(2),Co(SbO_(3))_(2),Ni(SbO_(3))_(2),FeSbO_(4),Fe(SbO_(3))4,MoWO_(6),TiSnO_(4),CoSbO_(4),and Ti(WO_(4))_(2)as promising catalysts,several of which have already been experimentally discovered for their robust OER performance,while others are novel for experimental exploration,thereby broadening the chemical scope for efficient OER *** of the bond length of TM-O and the first ionization energy were used to unveil the OER activity *** the calculated results,guidance has been derived to effectively execute advanced high-throughput screenings for the discovery of catalysts with favorable ***,the intrinsic correlation between catalytic performance and various atomic and structural factors was elucidated using the ML *** these approaches,we not only streamline the choice of the promising electrocatalysts but also offer insights for the design of varied catalyst models and the discovery of superior c

关键词： Transition metal oxides Oxygen evolution reaction High-throughput screening First-principles calculation Machine learning

Trends in colorectal cancer incidence according to an increase in the number of colonoscopy cases in Korea

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World Journal of Gastrointestinal Oncology 2024年第1期16卷 51-60页

作者： Ga Hee kim Yeong Chan Lee Tae Jun kim Sung Noh hong Dong kyung Chang Young-ho kim Dong-hoon Yang Chang Mo Moon kyunga kim Hyun Gun kim Eun-Ran kim Division of Gastroenterology Department of Internal MedicineAsan Medical CenterUniversity of Ulsan College of MedicineSeoul 05505South Korea Department of Digital Health Samsung Advanced Institute for Health Science and TechnologySungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSamsung Medical CenterSungkyunkwan University School of MedicineSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineEwha Womans UniversitySeoul 07985South Korea Biomedical Statistics Center Samsung Medical CenterSeoul 06351South Korea Division of Gastroenterology Department of Internal MedicineSoonchunhyang University College of MedicineSeoul 04401South Korea

BACKGROUND The incidence of colorectal cancer(CRC)and preinvasive CRC(e.g.,early colon cancer and advanced adenoma)is gradually increasing in several *** To evaluate the trend in incidence of CRC and preinvasive CRC according to the increase in the number of colonoscopies performed in *** This retrospective cohort study enrolled Korean patients from 2002 to 2020 to evaluate the incidence of CRC and preinvasive CRC,and assess the numbers of diagnostic colonoscopies and colonoscopic ***-related complications by age group were also *** The incidence of CRC showed a rapid increase,then decreased after 2012 in the 50-75 year-age *** the study period,the rate of incidence of preinvasive CRC increased at a similar level in patients under 50 and 50-75 years of *** 2009,the increase has been rapid,showing a pattern similar to the increase in *** rate of colonoscopic polypectomy in patients aged under 50 was similar to the rate in patients over 75 years of age after *** rate of complications after colonoscopy and related deaths within 3 mo was high for those over 75 years of *** The diagnosis of preinvasive CRC increased with the increase in the number of colonoscopies *** the risk of colonoscopy-related hospitalization and death is high in the elderly,if early lesions at risk of developing CRC are diagnosed and treated under or at the age of 75,colonoscopy-related complications can be reduced for those aged 76 years or over.

关键词： Colorectal cancer Preinvasive colorectal cancer Colorectal polypectomy Colonoscopy

Electroacupuncture for abdominal pain relief in patients with acute pancreatitis:A three-arm randomized controlled trial

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Journal of Integrative Medicine 2023年第6期21卷 537-542页

作者： Dong Kee Jang Jun Kyu Lee Chan Yung Jung kyung ho kim Ha Ra Kang Yeon Sun Lee Jong Hwa Yoon Kwang Ro Joo Min Kyu Chae Yong Hyeon Baek Byung-Kwan Seo Sang Hyub Lee Chiyeon Lim Department of Internal Medicine Seoul Metropolitan Government Boramae Medical CenterSeoul National University College of MedicineSeoul 07061Republic of Korea Department of Internal Medicine Dongguk University Ilsan HospitalDongguk University College of MedicineGoyang 10326Republic of Korea Department of Acupuncture and Moxibustion Dongguk University Ilsan Oriental HospitalCollege of Korean MedicineDongguk UniversityGoyang 10326Republic of Korea Department of Korean Medicine Dongguk UniversityGoyang 10326Republic of Korea Department of Acupuncture and Moxibustion College of Korean MedicineDongguk UniversityGyeongju 38067Republic of Korea Department of Gastroenterology Kyung Hee University Hospital at GangdongSeoul 05278Republic of Korea Department of Acupuncture and Moxibustion Kyung Hee University Korean Medicine Hospital at GangdongSeoul 05278Republic of Korea Department of Internal Medicine and Liver Research Institute Seoul National University HospitalSeoul National University College of MedicineSeoul 03080Republic of Korea Department of Biostatistics College of MedicineDongguk UniversityGoyang 10326Republic of Korea

Background: Electroacupuncture(EA) may reduce the severity of acute pancreatitis(AP) and provide additional pain relief in patients with chronic pancreatitis. however, the ability of EA to relieve pain in patients with AP has not been well ***: This study was undertaken to compare the pain-relieving effects of EA and conventional treatment in patients with ***, setting, participants and interventions: This study was conducted using a randomized, controlled,three-arm, parallel-group and multi-center design. Patients diagnosed with AP were randomly and equally assigned to EA1, EA2 or control groups. All participants received conventional standard-of-care therapy for AP. Local EA alone was administered in EA1, and local plus distal EA was given in *** EA included two abdominal acupoints, while distal EA included twelve peripheral acupoints. EA groups underwent one session of EA daily for 4 days(days 1–4), or until pain was resolved or *** outcome measures: The primary outcome measure was the change in the visual analogue scale(VAS;0–100) pain score between baseline and day ***: Eighty-nine participants were randomized into EA1, EA2 and control groups, and 88(EA1, 30;EA2, 29;control, 29) were included in the full-analysis set. VAS score change(median [interquartile range]) on day 5 was(12.3 ± 22.5) in the EA1 group,(10.3 ± 21.5) in the EA2 group, and(8.9 ± 15.2) in the control group. There were not significant differences in the change in VAS score among treatments(P = 0.983). however, time to food intake was significantly shorter in the EA group(EA1 + EA2) than in the control group(median 2.0 days vs 3.0 days), with a hazard ratio of 0.581(P = 0.022;95% CI,0.366–0.924). No significant adverse events ***: EA treatment did not significantly reduce pain after 4 days of treatment in patients with AP-associated abdominal pain but significantly reduced time to first food intake.

关键词： Acute pancreatitis Electroacupuncture Pain management Abdominal pain Randomized controlled trial