FEM을 이용한 선삭가공 절삭조건의 영향 분석

임세환,송춘삼,홍석관,강정진,김주현 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

A plane strain finite element model is developed to simulate turning with continuous chip formation using adaptive remeshing during the thermal-mechanical coupled analysis. Comparisons between the experimental and simulation results for cutting forces are performed to validate FE analysis results. Influences of machining parameters such as depth of cut, cutting speed and feed rate on cuting force and shear angle are analyzed by Taguchi method. The more depth of cut and feed rate result in the increase of cutting forces, but the rates of increase are decrease due to the larger shear angle. As the cutting speed increases, von Mises stress of workpiece near the tool tip decreases because the strength of specimen decreases at high temperature above 500℃. This thermal effect on cutting force is negligible because the affected area is very localized and the average values of von Mises stress in the shear plane are the same among the diverse cutting parameters.

방사선작업종사자에게 발생한 암의 업무관련성 평가를 위한 선별선량의 활용

정미선,진영우,임현술,김종순 대한산업의학회 2007 대한직업환경의학회지 Vol.19 No.3

철도건축물의 피난동선계획에 관한 연구

임만택,김현태,정집문 朝鮮大學校 建設技術硏究所 2004 建設技術硏究 Vol.24 No.2

The importance of the railway station is focused in this study, since it plays role of the traffic center in the region. This study is aimed to plan the escape flow in the railway station in order to maintain the safety and promote conveniency for passengers and loadings. The investigation of the escape flow is conducted for the most highly used platform and waiting room. Then, this study provides information in designing the railway station in terms of the case situation and types of railway building. Finally, this study gives useful information for determining the requirements for planning the escape flow in the railway buildings.

석면함유 슬레이트 지붕 물받이 퇴적물 중 석면 섬유 함유율

임지현,한솔민,김현석,신유민,박시은,허정윤,김민영,장봉기 순천향대학교 기초과학연구소 2022 순천향자연과학연구 논문집 Vol.28 No.1,2

This study attempted to determine the degree of asbestos release from the aging slate roof by comparing the asbestos content in the slate roof rain gutter with a colored steel plate (tin plate) over the slate roof. Four slate roof houses located in Haengmok-ri, Asan-si, Chungcheongnam-do, and one house constructed with a colored steel plate on the slate roof were selected to collect the sediment of the roof rain gutter. The asbestos fiber content was calculated by a point counting method using a polarization microscope after pretreatment with conversion treatment and hydrochloric acid treatment. The average asbestos content of the four slate roof rain gutter were 1.89%. However, asbestos was not detected in the Slate covering roof rain gutter, which were constructed on the slate roof. Asbestos fiber content was the highest at 2.89% in the slate roof rain gutter installed in 1976, followed by 2.44% in 1953. From the above results, it is necessary to minimize secondary damage as asbestos fibers released from slate roof houses to the surrounding atmosphere or leaked from slate roofs as rainwater may cause soil pollution and seriously affect residents' health. Although covering with colored steel plates (tin plates) has been shown to prevent the leakage of asbestos fibers to some extent, it is believed that a policy alternative to remove the slate roof as soon as possible is needed to solve the fundamental problem.

흰 쥐의 선상 절개 창상모델에서 저출력 레이저 자극이 조직 염증반응에 미치는 영향

임인혁,이정원,김현숙 한국전문물리치료학회 2003 한국전문물리치료학회지 Vol.10 No.2

The purposes of this study was to evaluate the effect of low power GaAsAl laser on tissue contraction in a linear incision wound on rat skin. The linear incision wound was made on the midline of the backside in the experimental animals. Low power laser applications with different intensities such as 3, 6, or 10 mW were applied to the experimental animals twice a day for 10 days. On either the seventh or tenth postoperative day, the quantitative analysis of the inflammatory reaction surrounding the linear incision wounds on the rats were performed using enzymatical analysis of myeloperoxidase (MPO) activity. The number of neutrophil was .07-1.0 × 106/㎖ from a normal blood sample that was obtained from the normal experimental animals. Each concentration of neutrophil showed .04-.62 unit activity of MPO. Therefore the unit activity of MPO per neutrophil was .57±.014 × 10-6 unit. On the 7th and 10th post operative day, non treated tissues demonstrated increased MPO activity as compared to that of normal tissue. These data indicated that the inflammatory reaction of tissue was induced after wound induction and the MPO activity were increased in the inflammed tissues. While both 3 mW or 6 mW intensity of laser treatments did not affect the tissue MPO activity, 10 mW intensity of laser treatment significantly decreased the tissue MPO activity on the 7th and 10th post operative day. These data demonstrated that only 10 mW intensity of laser treatment successfully suppressed tissue inflammatory reaction after wound induction. In conclusion, these findings suggested that 10 mW of GaAlAs laser treatments effectively suppressed the inflammatory reaction of tissue that was induced during the wound healing process.

미세형상가공시 센서융합을 이용한 공구 마멸 및 파손 메커니즘 검출

임정숙,왕덕현,김원일,이윤경 한국공작기계학회 2002 한국공작기계학회 춘계학술대회논문집 Vol.2002 No.-

A successful on-line monitoring system for conventional machining operations has the potential to reduce cost, guarantee consistency of product quality, improve productivity and provide a safer environment for the operator. In fine-shape machining, typical signs of tool problems such as vibration, noise, chip flow characteristics and visual signs are almost unnoticeable without the use of special equipment. These characteristics increase the importance of automatic monitoring in fine-shape machining; however, sensing and interpretation of signals are more complex. In addition, the shafts of the micro-tools break before the typical extensive cutting edge of the tool gets damaged. In this study, the existence of a relationship between the characteristics of the cutting force and tool usage was investigated, and tool breakage detection algorithm was developed and the following results are obtained. In data analysis, didn't use a relative error compare which mainly used in established experiment and investigated tool breakage detection algorithm in time domain which can detect AE and cutting force signals more effective and accurate.

인터넷을 활용한 초등 영어 수업의 구어 능력 향상에 관한 연구

임정완,구현정 大邱大學校 師範大學 附設 敎育硏究所 2009 學校敎育硏究 Vol.5 No.1

본 논문은 초등 영어 의사소통 능력의 향상에 그 초점을 맞추어 언어의 4가지 영역 듣기, 말하기, 읽기, 쓰기 영역 중에서 의사소통능력과 가장 관련 깊은 듣기, 말하기 부분 향상연구 방안에 초점을 맞추어 보았다. 총 72명의 초등학교 학생들이 본 연구에 참여하였으며, 각각 36명씩 통제반과 실험반으로 나뉘어 약 20주간 실험 관찰되었고, 실험 결과는 SPSS 12.0 으로 분석되었다. 각 과의 내용과 이에 부합하는 인터넷 자료 등을 통해 여러 번의 실험 수업을 거친 결과 학생들의 듣기, 말하기 실력이 향상되는 것을 지켜볼 수 있었다. 듣기와 말하기 실력의 향상 정도는 듣기가 말하기보다 조금 더 유의도에서 의미가 있었다. 즉 듣기가 말하기보다 실력 향상에 있어 조금 더 효과가 있음을 알 수 있었다. 학생들은 다른 매체들에 비해 쉽게 노출되고 또 그만큼 쉽게 즐길 수 있는 매체가 인터넷이라 보다 적극적인 자세로 수업에 임했다. 아직 저학년인 학생들이므로 지금의 영어에 대한 흥미도가 평생의 영어 실력을 결정 할 수 있는 만큼 이 시기의 흥미도는 절대적으로 중요하다는 것을 고려 해볼 때, 학생들이 흥미를 느끼며 동시에 실력까지 향상되어간다는 사실은 주목해 볼 필요가 있다. It is widely known that the Internet-based English teaching can be useful for students since it is not only a way of providing joy for them, but also a means of consolidating and extending their knowledge of the language. The purpose of this study is to investigate the effectiveness of the Internet-based English Teaching for Korean elementary schools students. For this purpose, a review of related literature was carried out to analyze various teaching methods using the Internet. Then the analysis of the elementary school students and curriculum that was performed in English classes was carried out. A total of 72 elementary school students participated in this study and they were divided into one comparison group and one treatment group, consisting of 36 students each. They were observed over 20 weeks and surveyed on their interests about learning English after the treatment was over. Before and after the treatment, students' spoken English ability in each group was also measured and analyzed by the use of SPSS 12.0. The findings of the study were as follows: First, the treatment group showed higher spoken English ability than the control group, especially in terms of listening ability. By being exposed to the Internet-based class activities, the treatment group had more opportunities to listen to and speak in English than the control group. Second, the students' interests about learning English significantly increased after being taught by the Internet-based class activities. In conclusion, it is recommended to design and apply the Internet-based English class that plays a positive role to improve oral English ability for Korean elementary school students.

한국판 섬망 평가 척도-98(K-DRS-98)의 표준화 연구

임경옥,김수영,이양현,이선우,김정란 大韓神經精神醫學會 2006 신경정신의학 Vol.45 No.6

Objective : This study was conducted to develop and to validate the Korean version of Delirium Rating Scale-Revised-98(K-DRS-98), which is a scale for diagnosing delirium and evaluating its severity. Method : After developing the K-DRS-98, 102 patients were rated by it among 4 diagnostic groups, such as delirium (N=25), dementia (N=27), schizophrenia (N=25) and others (N=25). To test for reliability, K-DRS-98 was independently administered by two psychiatrist. To test for validity, Korean version of Mini-Mental State Examination (MMSE-K) and Clinical Global Impression (CGI) were administered simultaneously. Statistical analysis was done with SPSS window version 12 package and statistical significance was p<0.05. Result : Intemal consistencies (Cronbach α) of two raters were 0.867 and 0.858, respectively. Inter-rater reliability (κ) was 0.893 for severity items of K-DRS-98 and κ value of diagnosis items was 0.969. In Delirium group, Pearson correlation Coefficients (r) of K-DRS-98 were -0.682 for MMSE-K and 0.667 for CGI. In comparison Delirium group with Others, ANOVA post hoc multiple comparison LSD was statistically significant (p<0.001). The cutoff score to diagnosis of delirium can be recommended 16 for seventy items and 21.5 for total score, respectively. Conclusion : The K-DRS-98 was showed good reliability and validity for the assessment of delirium. The K-DRS-98 is an easy and useful tool for diagnosing delirium and assessing its severity.

우관상동맥 개구부 완전 폐쇄가 동반된 대동맥 판상부 협착증 1례

임상현,김종진,김희열,진승원,전희경,노태호,채장성,김재형,홍순조,최규보,윤정섭,김치경 대한순환기학회 2000 Korean Circulation Journal Vol.30 No.4

효소적 방법으로 제조된 키토산 올리고당의 첨가에 따른 김치의 숙성 및 저장 기간 연장에 관한 연구

임현수,김진만,유은정,최명락 여수대학교 1998 論文集 Vol.13 No.2

효소로 처리된 키토산 올리고당의 첨가에 의한 김치의 숙성 기간 연장 효과를 알아보기 위하여 배추김치에는 0.2-0.4%, 2일째에 0.4%를 첨가하여 20℃에서 10일간 관찰한 결과 0.2% 첨가시 대조군에 비해 2일, 0.4% 첨가시는 4일, 2일째에 0.4%를 첨가한 경우는 8일 이후로 연장 효과가 2-4배 있었으며, 0.4% 이상에서는 미생물 생육자체가 억제되므로 풍미 및 유기산의 생성을 고려할 때 2일째 첨가된 0.4%가 젖산균의 수는 어느정도 유지하면서 stationary phage를 연장시킴으로서 더 좋은 결과를 나타냈다. 갓 김치의 경우 0.1%-0.5% 첨가시 대조군에 비해 1.2-1.4배의 연장 효과가 있어서 배추 김치에 비해서는 낮은 효과를 나타냈다. 따라서, 효소로 처리된 키토산 올리고당의 첨가에 의해 배추 김치는 2-4배의 연장 효과, 갓김치는 1.2-1.4배의 연장 효과를 나타내어 미생물 증식 억제에 의한 김치의 숙성 및 저장 기간 연장 효과를 기대할 수 있었다. To prolong the fermenting and preservation period of Kimchi, chitosanoligosaccharide was prepared by chitosanase. Various concentrations of chitosanoligosaccharide were added into Chinese cabbage Kimchi and Gat Kimchi. Chinese cabbage Kimchi was formulated with various chitosanoligosaccharide concentrations(0.2-0.4%) and fermented at 20℃. And Gat Kimchi was prepared with various chitosanoligosaccharide(0.1-0.5%) concentrations during 26 days at 4℃. In this results, the fermentation period was increased 2-2.5 and 1.2-1.4 folds more than control(0% of chitosanoligosaccharide) for Chinese cabbage Kimchi and Gat Kimchi, respectively. Conclusively, adding of chitosanoligosaccharide into Kimchi significantly prolonged the fermentation and preservation period.