TiAIN을 코팅한 WC공구의 절삭성능에 관한 연구

김현자,최현철,김영대,김일선,노태영,이규용 釜慶大學校 2001 釜慶大學校 論文集 Vol.6 No.-

Thin film of TiAlN was deposited onto ISO P20 tungsten carbide cutting insert tip substrate specimen using the FVAS (filtered vacuum arc system) at the substrate temperature of 80℃. Cutting and wear tests have been performed to the TiAlN coated and uncoated WC specimen, respectively under the same cutting conditions for the comparison. Cutting forces and tool wear of coated and uncoated carbide cutting tools were investigated by means of cutting length and cutting forces. Also tool wear and tool life were analyzed using the 3ch tool dynamometer amp lifier and oscilloscope. In this study cutting tests for the cutting performance of TiAlN coated WC-Co P20 to the steel alloy of SNCN420 have been curried out. Through the comparisons of cutting forces during the cutting tests and tool wear, we got the conclusions as follows.; ① In usual cutting conditions, main cutting force component showed higher value than the thrust force normal to the cutting direction especially cutting forces in the of early stage on cutting tests. But, after loosing the protective hard thin film on substrate or insert tip, the thrust force normal to the cutting direction showed much higher than main cutting force component. ② Within the range of 0.3㎜ build up edge in P20 insert tip, TiAlN coated tip was evaluated more stable in flank wear and less in crater wear than the uncoated specimen. ③ Through the wear growth curve of the specimen, tool life differences of uncoated and TiAlN coated tip at high speed (V=250[m/min]) was higher than the low speed(V=200[m/min]) case, compared to the average but the tool wear was almost same in both specimen for the case of normal wear occurred.

원격탐사를 위한 병렬계산 기법

김형중,장태정,김희원,김형수,이정문,장순자 강원대학교 석재복합신소재제품연구센터 1996 석재연 논문집 Vol.1 No.-

원격탐사에 사용되는 편미분방정식을 고속으로 풀기 위한 기법을 프로그래밍하고 성능을 향상시킬 수 있는 방법을 제시했다. 미지수가 30만개 이상되는 복소수(non-Hermitian) 행렬의 해를 구하는 프로그램을 작성했다. 이 프로그램은 C와 PVM에 기반을 두고 있다. 수렴속도를 향상시키기 위해 대각 스케일링을 이용했다. 통신속도의 개선을 위해 데이터 압축 기법을 이용했다. 수렴속도를 측정 제시함으로써 실제 문제 적용에 참고할 수 있다. Network-based computing with cluster of personal computers or workstations recently has become an important and successful technique. Network-based computing enables fast computation and resolves short of storage with computers on the desks. Cluster of inexpensive computers offers them aggregated computing power and storage to challenge very large-scale problems. Iterative solvers are used for the large sparse linear systems. Preconditioners accelerate the rate of convergence of the iterative solvers. However, parallelization accelerate the rate of convergence of the iterative solvers. However, parallelization of preconditioners is far from satisfaction so far. Thus, the simplest diagonal scaling is a good alternative for improved convergence and easy parallelization. In order to reduce communication overhead, a data compression technique is considered. Data communication time can be reduced at the cost of convergence rate. MATLAB simulation result is given in this paper. This method is effective to cluster of computers connected through slow networks.

超高眞空中의 Tribo-Coating의 潤滑特性

金亨資,全泰玉,加藤康司 釜山工業大學校 1994 論文集 Vol.36 No.-

Sliding friction between spherical pin of 8mm in diameter and flat(disk) substrates coated with vacuum-deposited thin film was measured under on ultra high vacuum pressure for various materials, rate of film supply(8∼210nm/min), sliding velocity(1.5∼67.0nm/s), flash temperature. It was found that the most effective lubrication is obtained when the adhesion between pin of Si₃N₄ and disk of SUS440C is high and that between pin of Si₃N₄ and disk of Si₃N₄ is low. When In film is used as a lubricant between pin of Si₃N₄ and disk of stainless steel, the friction coefficient has a value as low as 0.04. In this case, the normal load W and the sliding velocity V are expressed as 1ON and 24mm/s for 10??Pa. The dependence of μon the thickness h of the Ag film, which is used as a lubricant between Si₃N₄pin and SUS440C(Q) disk is expressed as μ=0.12 for W=10N and V=24mm/s when the film is thicker than 100nm. A brief discussion on these relations is presented from the viewpoint of the real contact area.

栽培年數에 따르는 人蔘精油量

金愛子,金英順,李榮子(B),李明淑 梨花女子大學校 藥學硏究所 1961 梨花藥學硏究 Vol.- No.2

서울 시내 일부 대학생의 성지식과 성태도에 관한 연구

김보배,노은경,박서영,박영,오승희,전영란,차현진,윤희상,김수지,이자형 이화여자대학교 간호과학대학 2004 이화간호학회지 Vol.- No.38

This study surveyed and analyzed comparatively college students-knowledge' attitude, was to cultivate the right knowledge and attitude on sex, and serve the foundational data for the suitable sex education. The purpose of the study was to identify and examine: 1) students; sexual knowledge and sexual attitude; 2) the differences between variables of gender, age, and self-perceived sexual knowledge in relation to sexual knowledge and sexual attitude; and 3) the relationship between sexual knowledge and sexual attitude. For this study the questionaires were given to 300 students from five different universities located seoul areas. the questionaires were collected Jenuary 8th to 15th in 2004. Two hundred and nigty one samples were analyzed for the study. The adapted SKAT(saxual knowledge & attitude test; Lief & Reed, 1986) was used to determine sexual knowledge and the students' sexual attitude. Collected data were analyzed statistically by means of percentage, t-test, ANOVA test, and pearson correlation analysis with SPSS 12.0 package program. The main results of this analysis are as follows: Participants consisted of male(48.1%) and female(51.9%) which were mainly between the ages of 21.25(71.8%) with an age range of 19 to 30. Knowledge of sexual disease was scored highest of 92.4%, and konwledge of the knowledge of the male and female's anatomy was the lowest at 60.9%. The respondents' level of sexual attitude was tolerant as on average 3.66(on the basis of 5) Relating to the items, the respondents' score of the sexual curiosity was 4.16, sexual behavior 3.85, self-consolation 3.81, aborthon 3.23, virgine 3.19, extramarital experiences 3.17. There were no significant differences in sexual knowledge between male and females, between younger and older students, residence, sexual experience, and how students mainly obtained their sexual knowledge. But a significant difference was also found religion in their sexual attitude(p<.005). In addition, results showed the relationship between sexual knowledge and sexual attitude(P=0.332).

질화규소와 베어링강의 미끄럼 마모형태도

김형자,최형순 釜慶大學校 1998 釜慶大學校 論文集 Vol.3 No.2

The tribological properties of silicon nitride in unlubricated sliding contact were investigated using a ball on disk wear apparatus at room temperature and normal load. The tribological behaviour can be classifled into two groups as follows : (1) The wear state of silicon nitride ball is divided into 3 parts, the formation of minute irragular surface resulted from plastic flow rupture, the formation of fracture surface of grain boundary and the formation of slippery surface resulted from chemical reaction. (2) The frication from of bearing steel disk is divided into 4 parts, the formation of the surface that the surface layer is shed resulted from friction wear, the formation of the surface that the microscopic friction particles are accululated resulted from corrosive wear and formation of surface that the slippery oxide tunic is created.

眞空中의 Grease의 중요한 潤滑 特性

金享資,白基英 釜山工業大學校 1985 論文集 Vol.27 No.-

Lubrication properties of four kinds of grease and PTFE in sliding friction were examined in detail in vacuum (10??P??-1.3×10??P??). Frictional specimens were made of stainless steel(SUS304) and their contact surface were finished by emery paper. The amount of grease supplied at the interface was changed in various degrees, and the change of frictional force was observed in sliding process. The coefficient of friction was low(μ 0.15) at the early stage of sliding in general but it increased suddenly after a certain sliding distance which was called the critical sliding distance. The critical sliding distance was small at low pressure (1.3×10??Pa) and was large at high pressure (10??Pa) . It decreased rapidly as the normal load increased. The critical sliding distance increased very sensitively at a certain amount of grease supplied.

묵은 김치 제조과정에서의 이화학적 및 미생물학적 특성 변화

유맹자,김형량,정희종 한국식생활문화학회 2001 韓國食生活文化學會誌 Vol.16 No.5

To develop the low-temperature and long-term fermented kimchi, kimchi was prepared according to the recipe of a specific ratio of major and minor ingredients and adjusted its salinity to 3.7%. Prepared kimchi fermented at 15±1℃ for 24 hours and transferred and fermented in a refrigerator only used to make low-temperature and long-term fermented kimchi at -1±1℃ for 30 weeks. During 30 weeks of fermentation the changes in physicochemical and microbiological properties of low-temperature and long-term fermented kimchi were studied. The initial pH of 6.47 decreased gradually and dropped to pH 4.0 after 14 weeks of fermentation, and then it maintained at same level. Acidity increased to 0.49% on 2 weeks of fermentation and kept at 0.47∼0.50% during 2 to 30 weeks fermentation. Salinity was slightly increased at early stage and started to decrease on 4 weeks of fermentation, and then it did not change. The change of reducing sugar content was closely related to the trend of pH change with a very high correlation coefficient(r=0.912). Lactic acid, citric acid, malic acid, succinic acid and acetic acid were major organic acids contained in low-temperature and long-term fermented kimchi. Vitamin C content decreased at initial stage of fermentation and then slightly increased up to the maximum of 22.3㎎% on 8 weeks of fermentation. In color measurement, L value continued to increase during the fermentation and reached at the highest of 55.45 on 22 weeks of fermentation, and a and b values of 3.62 and 4.54 also increased to 31.26 and 37.32 on 30 weeks of fermentation, respectively. Total microbial count increased slowly from beginning and was the highest on 4 weeks of fermentation, and then began to decrease slowly. Count of lactobacillus spp. was highest after 6 weeks, but count of Leuconostoc spp. was highest on 2 weeks of fermentation, and then both showed a slow decrease. Yeast count wasn't increased until 4 weeks of fermentation and then increased rapidly to get the highest on 10 weeks of fermentation.

大麥 및 白米 混合粉의 營養價値 硏究 : 第1報 보리의 搗精收率에 따른 營養價値 比較 硏究 Ⅰ. A Study on Some Nutritional Effects of Milling Recovery of Barley by Rats

辛炯泰,金永玉,具明子 成均館大學校 科學技術硏究所 1983 論文集 Vol.34 No.2

This experiment was conducted to observe the nutritional effects of milling recovery of barley (MRB) on the performance and digestibility by rats. Experiment was undertaken with 48 weanling male rats of Sprague-Dawley strain and they were evenly divided by 6 treatments, respectively, and feed and clean water were available, ad. libitum. In this experiment, the diets were consisted of corn starch+casein as control diet, 100%, 90%, 80%, 70% and 60% of MRB diet as experimental diets. For the experimental period, body weight gain(g), feed intake(g), feed efficiency ratio, protein efficiency ratio and digestibility (dry matter, organic matter, crude protein ; %) were measured to evaluate the nutritional effects of MRB diets for rats. The results which were obtained with this experiment as follows: 1. Average daily gain for 90%, and 100% MRB was 0.42g and for 70% MRB was 0.04g. And the differences between 80%, 90% and 100% MRB treatments and 70% and 60% MRB were significantly different(p<0.01). 2. Average daily feed intake was lower for 70% MRB of 3.41g and to increase the level of MRB tended to improve the feed intake, which followed the same pattern as the growth data. 3. Feed efficiency ratio was lower for 70% MBR of 0.01 and protein efficiency ratio was lower for 70% MRB of 0.15. 4. The range of dry matter digestibility was from 92.81% to 93.18%, organic matter digestibility was from 93.17% to 93.63% and protein digestibility was from 80.22% to 65.96% in 90%, 80%, 70% and 60% MRB, respectively. But there were no significant differences in dry matter, organic matter or protein digestibilities of experimental diets(p>0.01). And the digestibilities of dry matter, organic matter and crude protein for 100% MRB were significantly different compared with other treatments (p<0.01). So it may be concluded that 90% MRB would be the most nutritious processing method on the basis of feed intake, daily gain and protein metabolism by rats.

韓國 看護大學 敎育課程에 對한 硏究

文姬子,金潤喜,趙潔子,趙美映,姜賢淑 慶熙大學校 1982 論文集 Vol.11 No.-

The changes of social issues and nursing concepts require the expansion of nursing needs and nursing role, therefore it is keenly demanded the necessity of the research for new curriculum development in nursing. So to make a contribution to the development of nursing education in Korea, we made a comparative study of nursing curriculum of each universities which have baccalaureate program and put them into operation at present; they are 10 Korean universities, 5 American universities and 4 Japanese Universities. Thus by researching the differences among them. We acquired the conclusions as followings. The purpose of Nursing education In case of Korean parts, the contents of those aims must be explained more clearly and more in detail than another results of research. There also has to be made the statements upon the scientific researching methodology in scholarly respect, or the self-development in individual respect, or the lasting endeavour for studies in professional respect. We must put an emphasis upon the statement and education of the direct nursing provider, or the primary health care manager at hospital and community, who is one of the important aims of modern nursing education. The substance of nursing curriculum. 1) Total credits for completion and the comparison of curriculums, classified by the field. The scope of total credits of each nation, according to Colleges ranges; Korea: 140-163, U.S.A.: 121-187, Japan: 13-158 Compared with those of U.S.A. and Japan, the average credits of Korea is higher. Classified by the field, the credits alloted to major courses are 73.3% and liberal courses, only 26%, which shows that it does not satisfy the current educational trend that emphasizes the liberal course. 2) The comparison of curriculums, classified by a school year. In case of Korea, the total credits are evenly assigned to all grades, but the freshman taken the concentration of liberal courses (81.2%). Among the major courses are preponderant the Nursing Supportive subjects in the sophomore and the nursing major ones in the junior and senior. 3) Curriculums classified by the subject. (1) As compared with those of Japan and U.S.A. Korean students are less free in chosing subjects their own way all over the curriculums. It is, therefore, required that the range of the optionals be widened for the open and flexible education. (2) We can find all of three nations (Korea, Japan, U.S.A.) neglect the sphere of the behavioral sciences among the fundamental nursing subjects. In the field of social sciences, among Korea, Japan, and U.S.A., top ranks Japan that tends of the interested in social well-being. In Korea only two universities have this subjects. (3) Nursing major subjects. Defficulties in comparing them lie in the gulfs of the title of subjects, and the structural differences of the formation of curriculums among nations. In case of Korea, although there are a few differences of the number of credit of subjects among colleges, she has uniform aspects for U.S.A., which says that there are no characteristics and self-control each colleges has in Korea. We can notice that the subjects each Korean university shares are also doubled with those of the national examination for nursing qualification. Japan differs from Korea in that subjects are more differentiated and students are provided with more chances to make a choice through the system of subjects and the texture of a curriculum are similar to those of Korea. In case of Korea, therefore, the unification of fundamental subjects (especially in the medical field) and clinical practices is required. (4) The course for teaching profession is taken as either the required or optional just in Korea (80%) and Japan (75%). The number of subjects and total credits of teaching courses is different according to the colleges of Korea and Japan. As for the contents of subjects Korea deals with theory and Japan, the practical thing with which students can adjust themselves to the spot of society. As a result of that, in case of Korea, demanded are the entire review and research upon the purpose of establishing a curriculum, its relation to the total credits and the choice of substance of subjects etc. 4) The patterns of organization in curriculum development. Most of the patterns of organization, classified by clinic subject pivot upon disease and subjests are not mutually unified in case of Korea and Japan. Though the patterns of organization of subjects if formally unified, that of curriculums is not substantially or wholy synthesized, while in case of U.S.A. the unification of the patterns of organization entire curriculum as well as the mutual unification of subjects is attained and each college runs a characteristic curriculum, since the application of nursing theory and the model of a curriculum are different according to college. The prevention of disease, the promoting health and the disease system is patterned, centering around the healthy and their families. Therefore, in case of Korea, it is urgent to unify the curriculum of nursing education for the efficiency of the future oriented nursing education, and it is also imminent to develop the new pattern of a nursing curriculum suited for our own social demand and situation. And we need the continuous studies and search for the method of application in order to development the new curriculum. The comparison of a curriculum with the purpose of nursing education. The substances of subjects are not consistently in accord with the aims of nursing education each college states in Korea, Japan and U.S.A. Especially in case of Korea, the most statements upon the purpose of education are in the social dimension, but the most subjects have the academic dimension. In Korea it is stringent to examine and study the choice of the contents of education in terms of learning, profession, individual and society.