Study on Microstructure and Mechanical Properties of the Al–25Cr–5Si (at%) Alloy Powder Using Gas-Atomization and SPS Process

Yong‑Ho Kim,Hyo‑Sang Yoo,Jeong‑Han Lee,Ik‑Hyun Oh,Hyun‑Kuk Park,Hyeon‑Taek Son 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.7

In order to investigate the microstructure and mechanical properties on Al–25Cr–5Si (at%) alloy, a mixed powder with pureelements and an alloy powder using a gas atomization process were used. Fine and high purity Al–25Cr–5Si (at%) alloypowder was successfully prepared by gas atomization and densified using a spark plasma sintering (SPS) process. The overallpowder size distribution of the mixed Al, Cr, and Si elemental powders was in the range of 10–15 μm. The atomized Al–Cr–Sialloy powder was fine and spherical in morphology and difficult to be formed by intermetallic formation. Densification wasclearly confirmed at 1000 °C, with almost isolated pores formed, by clear removal of pores between particles, deformationof particles, an increase in the number of contacts, and a change in size between particles. As a result of XRD analysis ofthe sintered compacts, single phase was observed using the mixed powder, but the compact using gas atomization remainedthe alloy phase even at the process temperature. The Vickers hardness of the compacts by mixed powder was observed at59.70 Hv and the compact using gas atomized powders on the temperature 1000 °C of the Vickers hardness increased to702.6 Hv. The compressive yield strength of the compact with mixed powder was 195.24 MPa and the compressive strengthof the compact with gas atomized powder increased to 802.07 MPa. It is considered not to be decomposed by the AlCrSi,Al13Cr4Si4and Al8Cr5phases sintering process, resulting from the improvement of mechanical properties.

유량지속곡선을 이용한 한강수계 총량관리 단위유역 오염기여도 분석

이한필 ( Han Pil Rhee ),최재호 ( Jaeho Choi ),이성준 ( Yong Seok Kim ),김용석 ( Sung Jun Lee ),황하선 ( Ha-sun Hwang ) 한국물환경학회 2017 한국물환경학회·대한상하수도학회 공동 춘계학술발표회 Vol.2017 No.-

Estimating population density of Nicrophorus quadripunctatus (Coleoptera: Silphidae) in Korea

Kim Do‐Sung,Cho Young‐Bok,Han Yong‐Gu 한국곤충학회 2020 Entomological Research Vol.50 No.11

Estimating the population density of organisms is of great concern to ecologists and much effort has been put into making accurate assessment of population levels in nature. We evaluated the trapping web (TW) method for the determination of the density of species of burying beetles. We found eight and six species of burying beetles at Beopjusa and Ssanggok‐ri areas, respectively. Most of the species population comprised Nicrophorus quadripunctatus, with densities of 65 and 195 per ha for Beopjusa and Ssanggok‐ri areas, respectively. Moreover, the flight intercept trap (FIT) method from 2003 to 2007 also revealed the same trend: Beopjusa temple (2928) to Ssanggok‐ri (5835). However, the differences in number of individuals were probably due to the differences in the methods and the length of the trapping period. The populations of N. quadripunctatus exist as metapopulations, making accurate assessment of the population densities extremely difficult. We hypothesized that the TW method could accurately estimate population densities extrapolated from patch population size per area.

류마티스 관절염에 대한 한약의 면역학적 연구동향

최도영,이재동,백용현,이송실,유명철,한정수,양형인,박상도,유미현,박은경,박동석,Choi, Do-young,Lee, Jae-dong,Back, Yong-hyeon,Lee, Song-shil,Yoo, Myung-chul,Han, Chung-soo,Yang, Hyung-in,Park, Sang-do,Ryu, Mi-hyun,Park, Eun-kyung,Park, 대한침구의학회 2004 대한침구의학회지 Vol.21 No.4

Objective : Rheumatoid arthritis is an autoimmune disease that pathogenesis is not fully understood and one of the most intractable musculoskeletal diseases. The concern in the immunopathogenesis of rheumatoid arthritis has been increased since 1980's and many immunotherapeutic agents including disease-modifying antirheumatic drugs (DMARDs) were developed and became the mainstay of treatment of rheumatoid arthritis. However, the cure of the disease has hardly been achieved. In oriental medicine, rheumatoid arthritis is related to Bi-Zheng(痺證), that presents pain, swelling, andlor loss of joint function as major clinical manifestations, and also known to be deeply involved in suppression of immune function related to weakness of Jung-Ki(正氣). The herbal medicine, empirically used, could be a potential resource of development of new immunotherapeutic agents for rheumatoid arthritis. Methods : We developed a search strategy using terms to include "rheumatoid arthritis and herbal medicine" combined with "Chinese medicine" and/or "Oriental medicine". The search was focused on experimental studies of herbal medicine (January 1999 to May 2004), which is known to have effects on immune function of patients with rheumatoid arthritis. Computerized search used Internet databases including KISS and RISS4U (Korea), CNKI (China), MOMJ (Main Oriental Medicine Journal, Japan), and PubMed. The articles were selected from journals of universities or major research institutes. Results : The literature search for experimental studies on effects of herbal medicine on immunity of rheumatoid arthritis retrieved a total of 21 articles (Korea; 8, China ; 12, Japan ; 1). Of 21 articles, 10 were related to single-drug formula, 2 to drug interaction, and 9 to multi-drug formula. Single-drug formula was mainly used for aqua-acupuncture and researches on active components. Studies of drug interaction emphasized harmony of Ki-Hyul(氣血) and balance of Han-Yeul(寒熱). Multi-drug regimen was mainly found among formulas for Bo-Ki-Hyul(補氣血) and Bo-Sin(補腎). Conclusion : Studies on rheumatoid arthritis were performed both in vitro and in vivo in vitro study, LPS-stimulated splenocytes and synoviocytes were treated with herbal medicine, resulting in proliferation and activation of immune cells and suppression of cytokine activities in vivo study CIA animal model demonstrated that herbal medicine decreased antibody production and improved function of immune cells. In cellular and molecular study herbal medicine showed profound effects on the level of mRNA expression of certain cytokines related to immune function. This study revealed that herbal medicine has significant immune modulatory action and could be used for recovery of immune dysfunction of rheumatoid arthritis patients.

강원도 화천군 수달(Lutra lutra) 서식지의 식생 구조

서형수 ( Hyung Soo Seo ),신영섭 ( Young Seob Shin ),이경은 ( Kyung Eun Lee ),김윤미 ( Yoon Mi Kim ),전미나 ( Mina Jeon ),남택우 ( Taek Woo Nam ),한성용 ( Sung Yong Han ),정연숙 ( Yeonsook Choung ) 한국하천호수학회 2014 생태와 환경 Vol.47 No.special

In order to determine whether vegetation would be one of the factors for the selection of otter home range, vegetation structure and other potential factors were studied in Hwacheon, Korea. Thirteen sites, otter’s activity found and not found, were investigated in North Han River and connected tributary streams of Hwacheon-gun. Three types of vegetation were classified by cluster analysis, which is short grass, tall grass and shrub type. Vegetation zone of each channel is composed of either one type, or mosaic of tall grass and shrub type. Short grass type is common in Lake Paro and upper North Han-river where water level is highly variable throughout a year. Therefore, annual species such as Persicaria nodosa, Fimbristylis dichotomam and Chenopodium ficifolium are the most dominant. Shrub type is common at the downstream sites of Jichon stream and along mainstream of North Han River down Lake Paro. A shrub species, Salix koreensis, is the most common. Tall grass type is dominant occupying the most vegetation zone of the tributary channels. Phragmites japonica is absolutely dominant. Due to its dense cover, a few plant species are co-existed. Otter activity was found in all three vegetation types and no marked activity was found at some sites of tall grass type. There is no difference in species composition and physiognomy between tall grass sites with and without otter activity, while it shows significant difference in fish availability between two groups. Overall we found that home range of otters in the region is along the mainstream and downstream of tributary streams with high fish availability in all vegetation types and in various human activity levels.

초등 교과교육학의 성격과 내용구조 연구

유한구(Han Ku Ryu),장성모(Sung Mo Chang),송광용(Kwang Yong Song),조주연(Joo Yun Cho),이학주(Hak Ju Lee) 한국초등교육학회 1997 초등교육연구 Vol.11 No.1

이 연구는 교과교육과 교과교육학의관계, 그리고 교과교육학과 교육학의 관계등을 분석하고, 그 결과를 토대로 하여 초등학교 교과교육과 교육대학 교과교육학 교육의 실제를 정확히 이해하고 그 발전 방향을 탐색하기 위한 것이다. 일반적으로, 교과교육학은 교육학에서 제시하고 있는 교육과정의 구성및 교육방법상의 일반 원리를 교과교육이라는 특수한 사태에 적용하는 과정에 관심을 두는 이론으로 간주되고 있다. 이 관점에 의하면, 교과교육학은 교육학의 일반적 원리에 따라 교과교육이라는 특수한 맥락에 처방을 내리기 위한 것으로 파악된다. 이 관점을 교과와 그것을 가르치는 교사의 삶을 사실상 별개의 것으로 분리하는 것이며, 그와 동일한 이유에서 교과교육학과 교과교육학자의 삶 또한 별개의 것임을 전제하는 것이다. 그러나 교과교육과 교과교육학, 그리고 교과교육학과 교육학의 관계는 이론에서 실제로 나아가는 앞의 방향과는 정반대 방향에서도 이해될 수 있다. 이 관점에 의하면, 교과교육학은 교과교육 실제에 처방을 내리기 위한 것이 아니라 그 실제를 기술하고 정당화하기 위한 것으로 파악된다. 교과교육과 교과교육학의 관련이 이렇게 파악될 때, 교과 교육학은 교사나 교과교육학자에게 자신이 지금 하는 일이 자신의 삶과 결코 무관한 것이 아니라는 믿음을 심어 주게 되며, 나아가 그들 자신이 참여하고 있는 초등학교나 교육대학의 교육실제를 기술하거나 정당화하려고 할 때 반드시 필요한 개념적 도구를 제공해 줄 수 있게 된다. 바로 여기에 교과교육학에 관한 종래의 접근과는 구분되는 새로운 접근방식이 요구되는 이유가 있다. The purpose of this study is threefold: The first is to analyse the relations between subject education and subject pedagogy, and between subject pedagogy and general pedagogy. The second is, based on the analysis result, to have the precise understanding of teaching various subjects in the elementary school, and of teaching subject pedagogy in the university of education. The third is to search for the desirable direction of developing the elementary education and the teacher education. Subject pedagogy is usually defined as a theory which is interested in the process of applying pedagogical principles regarding curriculum organization and teaching methods to specific teaching situations, that is, subject education situations. However, this definition has a limitation, because it assumes that a subject and the teacher's life who teaches the subject are separated from each other, and that subject pedagogy and the scholar who studies subject pedagogy are also separated. The relationship between subject teaching and subject pedagogy, and between subject pedagogy and general pedagogy can be understood with quite different viewpoint. This new viewpoint, which is the major discussion matter of this study, assumes that subject pedagogy is never separated from the life of subject teacher/subject pedagogist. This viewpoint will reveal the theoretical features of subject pedagogy better, and give us new meaning on the life of teachers/subject pedagogists. The subject pedagogy in the correct sense should provide teachers/pedagogists with the conceptual instrument based on the new viewpoint. This conceptual instrument will make teachers/pedagogists be able to describe, explain, and validate their own educational practice-such as the content structure of each subject-in the elementary school or the university of education.

[P450] Subungual exostosis mimicking subungual fibroma

( Yong Woo Oh ),( Sook Hyun Kong ),( Seok Hyun Han ),( Ji Hyun Kim ),( Ho Seok Suh ),( Yu Sung Choi ) 대한피부과학회 2017 대한피부과학회 학술발표대회집 Vol.69 No.1

Subungual exostosis is an uncommon benign osteocartilaginous tumor arising from the distal phalanx. It presents as a bean-sized skin-colored firm nodule, predominantly found on the great toe. There is no proven etiology for subungual exostosis, but trauma and longstanding infection could be causative factors. Histopathologycally, subungual exostosis shows a mature trabecular bone covered by a proliferating fibrocartilaginous cap. The gold standard for diagnosis is radiographic examination which typically shows a trabecular bony outgrowth. The differential diagnosis of subungal exostosis includes osteochondroma, subungal verruca, pyogenic granuloma, and subungual fibroma. The treatment of choice is surgical excision of the lesion, including the osteocartilaginous cap. An 11-year-old boy presented with 1-year history of a painless skin-colored papule on the right 4th finger. Excisional biopsy was done under the impression of subungual fibroma and histopathologic findings from the excised specimen showed fibrocartilaginous cap with underlying trabecular bone formation. Therefore, the patient was diagnosed with subungual exostosis. Herein we report a case of subungual exostosis of a finger mimicking subungual fibroma.

Development of TILLING System for Screening of Target Gene in Pepper Mutation Population

Han Sol Kang,Yeong Deuk Jo,Sang Hoon Kim,Se Won Kim,Sun-Young Kim,Sang-woo Lee,Si-Yong Kang 한국원예학회 2017 한국원예학회 학술발표요지 Vol.2017 No.5

Effect of Preadmission Metformin Use on Clinical Outcome of Acute Respiratory Distress Syndrome among Critically Ill Patients with Diabetes

( Yong Suk Jo ),( Sun Mi Choi ),( Jinwoo Lee ),( Young Sik Park ),( Chang-hoon Lee ),( Jae-joon Yim ),( Chul-gyu Yoo ),( Young Whan Kim ),( Sung Koo Han ),( Sang-min Lee ) 대한결핵 및 호흡기학회 2017 Tuberculosis and Respiratory Diseases Vol.80 No.3

Background: Acute respiratory distress syndrome (ARDS) is related to high mortality and morbidity. There are no proven therapeutic measures however, to improve the clinical course of ARDS, except using low tidal volume ventilation. Metformin is known to have pleiotropic effects including anti-inflammatory activity. We hypothesized that pre-admission metformin might alter the progress of ARDS among intensive care unit (ICU) patients with diabetes mellitus (DM). Methods: We performed a retrospective cohort study from January 1, 2005, to April 30, 2005 of patients who were admitted to the medical ICU at Seoul National University Hospital because of ARDS, and reviewed ARDS patients with DM. Metformin use was defined as prescribed within 3-month pre-admission. Results: Of 558 patients diagnosed with ARDS, 128 (23.3%) patients had diabetes and 33 patients were treated with metformin monotherapy or in combination with other antidiabetic medications. Demographic characteristics, cause of ARDS, and comorbid conditions (except chronic kidney disease) were not different between metformin users and nonusers. Several severity indexes of ARDS were similar in both groups. The 30-day mortality was 42.42% in metformin users and 55.32% in metformin nonusers. On multivariable regression analysis, use of metformin was not significantly related to a reduced 30-day mortality (adjusted β-coefficient, -0.19; 95% confidence interval, -1.76 to 1.39; p=0.816). Propensity score-matched analyses showed similar results. Conclusion: Pre-admission metformin use was not associated with reduced 30-day mortality among ARDS patients with DM in our medical ICU.

Comparisons between Standard and Extended Pelvic Lymph Node Dissections During Radical Cystectomy in Patients with Bladder Cancer

Sang Eun Lee,Hakmin Lee,Hyun Hwan Sung,Seong Il Seo,Seong Soo Jeon,Hyun Moo Lee,Han-Yong Choi,Byong Chang Jeong 대한비뇨기종양학회 2016 대한비뇨기종양학회지 Vol.14 No.3

Purpose: We compared the staging ability and early complications of standard and extended pelvic lymph node dissection (sPLND and ePLND, respectively) in patients with localized bladder cancer during radical cystectomy. Materials and Methods: We prospectively collected and analyzed the data of 261 patients who underwent radical cystectomy for localized bladder cancer. The resected lymph nodes were categorized according to anatomic locations and were carefully inspected by an experienced pathologist. The perioperative complications were classified using the Clavien-Dindo classification system. Results: The 2 groups showed no significant differences in preoperative characteristics except for preoperative clinical stage (p=0.015). There were no significant differences in pathologic outcomes including pathologic stage, positive surgical margin, and lymphovascular invasion (all p>0.05), but the sPLND group showed a significantly higher cellular grade (p<0.001). The ePLND group showed a higher number of removed lymph nodes than the sPLND group (p=0.015) and a higher rate of positive lymph node invasion (35.8% vs. 28.9%). There were no significant differences in complication rates according to the extent of lymph dissection and urinary diversion type, respectively (p=0.063 and p=0.486). Conclusions: The ePLND showed more accurate nodal staging ability with comparable complication rates when compared to sPLND in patients who underwent radical cystectomy for localized bladder cancer. A further, larger prospective study is needed to confirm the result of the present study.