'79학년도 본대학 신입생에 대한 학업성적 분석

김정두,윤지헌 영남이공대학 1979 論文集 Vol.8 No.-

This study is one of the continuous work following the preceding analysis in 1977 which has suggested some data in the better improvement of evaluation methods on the students' achievement. Throughout the study, the academic records of 1,699 YJCT freshmen have been used as the reference materials. The main results obtained by this study have revealed the following: First, differences of standard in marking the test scores among the individual course subjects are still existing. Second, the achievement scores of the general selection students for the college admission are higher than the special selection students in the subjects of general education course such as Korean, Ethics, History, English and Mathematics, but contrary lower in the major subjects. Third, the scores for college admission including both Preliminary College Entrance Examination and High School Achievement are not so highly correlated with the college achievement scores as expected. Fourth, no distinct differences have been found according to the years passed after the high school graduation. The college academic achievement scores of the technical high school graduates, however, seemed to be influenced by the reputation of their parent schools. With the above results, it is suggested that a professional study to develop the better selection system of entrance examination, to improve the methods for instruction, evaluation and organization of the course subjects, and to render more effective student guidance should be continued.

절삭가공중의 공구수명검출 시스템 개발에 관한 연구

김정두,최종순 한국기술사회 1988 技術士 Vol.21 No.4

The study on the progress of automatic machining system has been active centering at the CNC machine tools recently to lead the applied production technology like unmaned machining to the practical level, and to make these application more efficient, they require detective method for tool wear and breakage while machining. In this study chiefly on turning, first derive cutting force about the tool surface by the cutting resistant sensor and with which change into electric signal and compare with the standards to make the tool life detection system to let know the tool life and study its application; the cutting resistance detected by the cutting resistant sensor has increased to the level of standards, the measuring system which can decide whether we change tools on the basis of comperative circuit is shown to be very reliable model for cutting tool life detection system.

초정밀 절삭가공의 현상과 향후 동향

김정두 한국기술사회 1990 技術士 Vol.23 No.4

切削加工 의 光彈性的 現象 에 관한 硏究 (II)

김정두,이용성 대한기계학회 1984 대한기계학회논문집 Vol.8 No.5

본 연구에서는 구속공구 및 정상공구에 대하여 공구경사면의 전단응력과 수직 응력을 해석하고 칩 유동시의 마찰계수분포를 검토하였다. In the previous paper, part I, the principal stresses were investigated on the normal tools and the workpieces whose materials were the same epoxy resin. In this paper, are measured and compared the stresses on the normal tools and restricted tools which have three various rake angles. Each restricted tool above has the same restricted angle. The workpieces used in this experiment are made of high quality lead. The photoelastic measuring device is attached to the saddle of the lathe and carried at the same speed as the cutting tool is feeded. The results obtained are summarized as follows; The shear stresses on the tip of the restricted tools of the rake angle .alpha.=12.deg. and .alpha.=0.deg. are less than those of normal tools. But, for the rake angle .alpha.=-12.deg., the former is greater than the latter. The result of photoelastic method shows that in the range of rapid decreasing of normal stress on the tool edge, the shear is maintaining a certain value.

切削加工 의 光彈性的 現象 에 관한 硏究( I )

김정두,이용성 대한기계학회 1983 대한기계학회논문집 Vol.7 No.2

In this study the phenomenon of cutting stress which arises on cutting tools and work pieces in cutting process is investigated by rake angle of cutting tools and feed for this measurement, P$_{s}$-1 (high modulus, photolastic Inc.) was used as a cutting tool, P$_{s}$-3 (medium modulus, photolastic Inc.) was used as work piece and reduction apparatus was attached to the head stock, and orthogonal cutting was adapted as a cutting method and transparent glass was used to block the strain in the orientation of thickness. The followings are the results of this study. (1) Photoelastic experimental equipments have made it possible to make dynamic measurement and analyze stress distribution in cutting tool and work piece surface which has hitherto been conducted only in static measurement and analyzing method. (2) The maximum stress arising at tools and work pieces in cutting process is on the tool edge tip, and the maximum stress arising on the tip of cutting tools is equal to that on the contacting area of work pieces in values. (3) The distributions of maximum shear stress on certain parts of the cutting tools and work pieces are as follows; for cutting tools, .alpha.=12.deg., .alpha.=0.deg., .alpha.=-12.deg. in order, and for work pieces, .alpha.=-12.deg., .alpha.=0.deg., .alpha.=12.deg. in opposite order.der.

서독의 절삭가공 및 공작기계연구소(ITW) 소개와 연구동향

김정두 대한기계학회 1988 大韓機械學會誌 Vol.28 No.1

ITW는 응용연구에 많은 비중을 두고 있으며 산업체와 공동으로 팀을 구성하여 연구함으로서 치열한 국제 경쟁력 기술을 강화하고, 생산현장이 안고 있는 기술적인 문제점을 분석하고 해결 하는데 선도적인 역할을 하고 있다. 한편 연구 결과로 얻어진 자료들은 단기간 내에 신기술 교육으로 활용, 생산성에 접근된 교육방안의 제시와 함께 현안 문제점을 해결할 수 있는 인재를 양성함으로서 연구와 교육을 하나의 연속체로 하고 있음을 알 수 있다. 한편 이의 뒷받침을 위하여 지속적인 정책과 투자가 효율적으로 이루어짐으로서 그의 결과를 극대화시키고 있다.

천연 다이아몬드 인선형태에 의한 Al 합금의 경면절삭에 관한 연구

김정두 대한기계학회 1990 대한기계학회논문집 Vol.14 No.6

Ultra precision cutting should be satisfied with two conditions of Mirror Like and shape grade, and especially Mirror Like depends on surface roughness. In this study, in order to develop Mirror Cutting for Al alloy, this was done with edge form of single crystal diamond tool divided into R type and S type. Surface roughness machined by S type tool is more satisfactory than by R type tool, being the lowest value of 13.8nm. In addition, Mirror surface can reach above 90% of reflection rate by both R type and S type tool, but machined surface by R type tool has much more fine fracture portions rather than by S type tool. Even though feed rate decreases from 5.mu.m to 1.mu.m, surface roughness doesn't show improvement. 본 연구에서는 천연다이아몬드의 인선형상을 R형과 S형으로 구분하여 제작하 고 미세이송과 절삭속도 변화를 주어 이에 얻어지는 표현거칠기, 칩 생성기구 및 경면 성을 검토하였다.

꾸밈음(裝飾音)에 對한 考察

金正斗 群山敎育大學 1974 論文集 Vol.7 No.-

There are Composer's feeling and thoughts in the musical tones and the tones make the audience cause to feel something different. Music, the expressive and time art, needs some rhythms and they are consisted of harmonic tones which produce different feelings by the tone color, stsess, and duration of sound. It is quite natural that we should try to express the beautiful tones to the touched one's feelings and imitated nature's beauty by using the various ornamental tones. In this paper I try to investigate the nature and the characteristics of the ornamental tone and to analyze and classify them. And besides, I intended to establish a system of the ornamental tones which would make practical application of them gradually. So far at every level of school from primary school to college, the music education in Korea has emphasized the superficial and general expressions, so that especially the primary school children were bored and uninterested in singing and in playing the musical instruments, such as piano or violin. And it is also true that they were within the frame of mechanism and uninteresting apathy in the music education. That's the reason why I suggest the systematic and gradual ways of application at the primary and secondary school.

裡里工團勤勞者의 勤勞條件 : 賃金 中心으로

金正斗,金恭鉉,申海錫,崔珉秀,尹美子,高鎬子 圓光大學校 行政學科 行政學硏究會 1988 행정논총 Vol.8 No.-

절삭가공에 있어서의 광탄성학적 현상에 관한 연구

김정두 단국대학교 1983 學術論叢 Vol.6 No.-