CFRP적층쉘의 적층구성 및 곡률반경에 따른 관통특성

임광희,조영재,이길성,심재기,김영남,양인영 朝鮮大學校 機械技術硏究所 2004 機械技術硏究 Vol.7 No.1

최근 탄소섬유 강화 복합재료(이하 CFRP)는 비강도, 비강성이 높아 경량화가 요구되는 우주항공분야에서 구조용 재료로 널리 이용되고 있다. 본 연구에서는 CFRP 적층쉘의 적층구성 및 곡률반경에 따른 관통 특성을 고찰 하고자 한다. 실험에 사용된 복합재료는 일방향 프리프레그시트로서 적층방법은 〔0₃/90₃〕, 〔0₂/90₂〕s,와 〔0₂/90₃/0〕s, 〔0/90₂/0〕 2계면과 4계면으로 적층하였다. 그리고 다양한 곡률 반경을 적용하였다. (R= 100, 150, ∞). 적층순서에 맞게 적층된 시험편은 경화온도 130℃에서 진공백 성형과정을 오토클레이브로 제작 하였으며 100x140mm 크기로 절단 하였다. 시험편은 강구로 관통시켰으며 ballistic-screen sensor로 속도를 측정하여 충격전 운동에너지와 충격 후 운동에너지를 구할 수 있다. 흡수에너지는 곡률이 커질수록 증가하였으며 4계면 시험편보다 〔0₃/90₃〕s 와 〔0₂/90₂〕s 적층구조를 갖는 2계면 시험편이 흡수에너지가 더 높게 나왔다. Currently, carbon-fiber reinforced plastics (CFRP) are widely used in both space and civil aircraft due to their superior stiffness and strength to weight ratios compared to conventional metallic materials. This paper is to study the effects of curvature and staking sequence on the penetration characteristics of CFRP laminated shell. Composite laminates used in this test are CFRP orthtropic laminated plates, which are stacked with two-interfaces 〔0₃/90₃〕s, 〔0₂/90₂〕s and 〔0₂/90₃/0〕s. 〔0/90₂/0〕s. They are manufactured to varied curvature radius (R= 100. 150, 200 mm and ∞). They are cured by heating to the appropriate hardening temperature(130℃) by mean of a heater at the vacuum bag of the autoclave. Test specimens were prepared with dimensions 100mmx140mm. When the specimen is subjected to transverse impact by a steel ball, the velocity of the steel ball was measured both before and after impact by determining the time for it to pass two ballistic-screen sensor located a known distance apart. Absorbed energy increased as the curvature increased. 〔0₃/90₃〕s and [0₂/90₂〕s specimens, which is small interlaminar number, was higher than fore interlaminar specimen.

CFRP 적층판의 초음파 특성평가

임광희,허욱,이길성,박제웅,김선규,양인영 한국공작기계학회 2006 한국공작기계학회 추계학술대회논문집 Vol.2006 No.-

Ultrasonic NDE of composite laminates is usually analyzed on the backwall echoes of the specimen. In the inspection of actual composite structures, the back surface of the part was curved or contained complex geometry and did not provide a usable backwall echo. In this work, a one-sided pitch-catch setup was used in the detection and evaluation of flaws and material anomalies in solid composite laminates. Two miniature potted Rayleigh wave transducers (for generating surface waves in contact mode on steel) were joined head-to-head and used in the pitch-catch mode on the surface of composites. The pitch-catch signal was found to be more sensitive than normal incidence backwall echo of longitudinal wave to fiber orientation of the CFRP composites, including low level porosity, ply waviness, and cracks.

높은 지향성을 갖는 Air Line 결합기 설계

길준범,이성원,최영호,박종임,안달,박준석 호서대학교 반도체제조장비국산화연구센터 2000 학술대회 자료집 Vol.2000 No.1

본 논문에서는, 일반적인 스트립 구조의 결합기가 갖는 문제 즉, 높은 온도에서 나쁜 특성을 보이는 문제점을 극복하고자 Air Line Type의 결합기를 구현하였다. 또한 이 결합기는 24dB이상의 지향성을 가지고 있다. 해석을 위해 짝수 모드와 홀수 모드 해석법을 사용하였고, EM-Simulation으로 확인한 특성과 실제 제작된 20dB, 30dB Cellular 대역(800∼900MHz) Air Line 결합기의 결고 특성은 좋은 일치를 보여주고 있다. 또한 최대 장점인 온도 특성은 온도 데이터를 통하여 온도에 강한 특성을 보임을 알 수 있다.

흰쥐에서 간담관 장애가 신장에 미치는 초미세 형태학적 연구

김용임,김일,이길부,최종범,기근홍,김용일,서재홍 朝鮮大學校 附設 醫學硏究所 1991 The Medical Journal of Chosun University Vol.16 No.1

It has been well-known that biliary cirrhosis with concomittant impairment of renal functions were occured after prolonged obstruction of biliary tract. In the present study, an attempt was made to investigate the mechanism of impaired renal function and the ultrastructural change of the kidney in rats, ligated the common bile duct for 21, 28 and 50 days in order to induce secondary biliary cirrhosis. The results obtained were as follows ; 1. Secondary biliary cirrhosis was produced evidently 28 days after ligation of common bile duct. Prominent proliferations of bile ducts and chronic inflammatory cell infiltrations were seen in pehportal area. 2. 28 and 50 days after ligation of common bile duct, show swelling and degeneration of mitochondria, microcystic formation and lysis of endoplasmic reticulum in the hepatocytes. Loss of microvilli in the bile ductules were noted. 3. Focal fusions, edema and bleb formations of foot processes were seen. Electron dense materials with variable size and global shape were found in foot process, 21, 28 and 50 days after ligation of common bile duct. 4. There were slightly thickening of renal glomerular basement membrane with hump in the subendothelial and widening of the mesangial matrix, 28 days after ligation of common bile duct. 5. There were moderately thickening of renal glomerular basement membrane and widening of the mesangial matrix with electron dense deposits, 50 days after ligation of common bile duct. From the above findings of electron microscopy, this study revealed electron dense deposits on renal glomerular mesangium of the rats as a results of experimental secondary biliary cirrhosis by ligation of common bile duct. Also severe hepatic injury due to swelling or lysis of rough endoplasmic reticulum and destruction of bile ductules resulted in deposited electron dense materials due to inhibition of excretion of immune complex through hepatobiliary tract, therefore this change indicated that immuncomplex could be deposited on renal glomerular mesangium.

生分解性 共重合體의 重合 및 物性에 관한 硏究(I)

崔乘載,吉德洙,趙壬元 단국대학교 1995 論文集 Vol.29 No.-

The graft ploymerization of methyl methacrylate onto starch initiated by ceric ammonium nitrate. The grafted polymer was identified by using IR spectroscopy. Four copolymer samples with grafting percents of 34.29%, 48.71%, 57.89% and 67.89% were tested for their microbial susceptibility in a synthetic medium employing a inoculum of aspergillus niger, trichoderma viride. Starch-g-poly(methyl methacrylate)copolymer films show excellent susceptibility to fungal growth, some samples losing more than 14% of their weight after 15days of incubation with aspergillus niger. There was initial rapid weight loss accompanied by the exponential increase in bacterial population and pH of the culture medium during the second week. The extent of degradation seems to decress with increasing grafting percent.

화학 및 마이크로파 고정에 의한 흰쥐 혀의 조직화학적 특징

김완종,신길상,이승임 순천향대학교 기초과학연구소 1995 순천향자연과학연구 논문집 Vol.1 No.1

The rat tongue tissues were fixed with chemical and microwave to compare the staining characteristics in different cases. The used microwave oven was equipped with infrared temperature sensor which developed in this laboratory and the control groups(chemical fixation) are treated with 3.5% neutral formalin. The microwave fixation is effective far above average in comparison with the chemical fixation. The optimal temperature measured by chromium - nickel thermocouple was 27±2℃ in physiological saline solution and therefore, this temperature was used for routine histological and histochemical works. It is to say in this work that the microwave fixation methods reveal more distinct histochemical reaction and save the fixative duration. The various preparations applied to minimize the preparation time. such as the freezing-section.

여성용 춘추복지의 태에 관한 연구 (제1보) : 태의 주관적 평가척도 개발을 중심으로 Development for the Subjective Hand Evaluation Scale

홍경희,김재숙,박춘순,박길순,이영선,김재임 한국의류학회 1994 한국의류학회지 Vol.18 No.3

KES-F system is widely used in hand evaluation, however, it has encountered some challenges, such as the overlapping of primary hand value, lack of predictability in case of women's thin dress, difficulties in communication due to complexity of primary hand expression and cultural differences in subjective evaluation. Therefore, this study was intended 1) to find out the Korean primary hand expressions (factors) of the overall concept of fabric hand associated with women's spring-fall dress fabrics, 2) to develope the fabric hand attributes of those fabrics and 3) to show whether there are any differences between Korean textile experts and non-experts in terms of the concept of fabric hand descriptors of hand attributes. Data base of hand descriptors were collected by extensive interview 60 experts and 10 non-experts using 110 spring-fall dress fabrics. Finally, hand of selected fabrics was assessed by 205 experts and 265 non-experts using 7-point scale of 26 descriptors based on the data base. Subjective ratings were analyzed by common factor analysis with varimax rotation. It was found that Korean primary hand expression indicated rather simple property, hence, did not equate exactly with Japanese experssion(e.g. koshi, shinayakasa, etc.) which contains several material properties. There were differences in stretch & resilience, especially liveliness, between the judgement of non-expert than to experts. Surface-related category was more important to non-experts than to experts. Slight differences were found between both groups in terms of preferred descriptors. Important descriptors as a rating scale were suggested.

학술 텍스트에 나타난 핵심 구문의 추출 -국어국문학 학술논문 말뭉치를 중심으로-

남길임 ( Kil Im Nam ),최준 ( Jun Choi ) 한국문학언어학회(구 경북어문학회) 2014 어문론총 Vol.60 No.-

The present paper has two big goals. The first aim is to extract word sequences which have high keyness in academic corpus and to discuss about a methodology of the extraction of academic key-sequences. The second aim is to consider discoursal functions of academic key-sequences distinguished from academic formulaic expressions which have high frequency in the corpus. For these goals, we use two kinds of corpus, one is, as a target corpus, 400,000 words academic corpus in the field of Korean linguistics and literature, the other one is, as a reference corpus, 10 million words a Sejong written corpus. We use these two corpus to extract word-sequences which have a relatively high keyness as well as absolutely high frequency. For identifying key-sequences for the corpora, the tool used is the program called KNU-Combiner produced by KNU research team. In order to calculate keyness, chi-squared test was used. The finally extracted key-sequence list tells us that academic key-words show the topic of the academic field, whereas the key-sequences represent the stylistic traits of the academic field, and that key-sequences play a role as a semantic unit in a specific genre like a word.

핵심어 분석의 절차와 쟁점 -국어국문학 분야 학술논문 핵심어를 중심으로-

남길임 ( Kil Im Nam ),이수진 ( Su Jin Lee ) 한국텍스트언어학회 2012 텍스트언어학 Vol.32 No.-

The present paper provides an introduction to the procedure of keyword analysis, including some issues on the creation of Korean keyword lists. It also deals with which grammatical unit is the best in analyzing Korean keywords and how to classify keywords by their range and textual functions in corpus. The tool used for identifying keywords in this paper is WordSmith Tools 6.0 and the corpus comprise 400,000 words academic corpus in the field of Korean literature and linguistics as a main corpus. We also use 10 million words Sejong written corpus as a reference. In recent years, there has been wide interest in statistical approach to keyword analysis. However little research has been carried out with Korean keywords. This is a experimental research which aims to demonstrate how keywords analysis can contribute to the interpretation of Korean academic corpus from the perspective of aboutness and text style.

구어 비유창성 현상의 주석 체계 연구

남길임 ( Kil Im Nam ) 한국텍스트언어학회 2011 텍스트언어학 Vol.30 No.-

The purpose of this research is to study the semantic and pragmatic characteristics of disfluency phenomena and to develop a tag set by analysing the types of the disfluency in Korean spoken language. The term ``disfluency phenomena`` can be defined as language expressions which can be occurred from the characteristics of spoken language as a medium. It is a term that implies the discourse markers, filled pause and phenomena related disfluency which cannot be contributed to the propositional information of the expression. This study defines 3 main categories of these phenomena and classifies several sub-categories according to the semantic and pragmatic features of disfluency phenomena. Then I present distribution the distribution of these categories. The results of this research will take a significant role for the syntactic analysis of spoken language. After extracting disfluency phenomena, the spoken language corpus will be composed of propositional information, which becomes the proper form to be used with a parser.