방사선사진의 인덱스-순서 분석을 통한 치아경조직의 탈염화 검출

박동현,박영호,김경숙,박정훈,이기자,최삼진,최용석,황의환,박헌국 대한구강악안면방사선학회 2009 Imaging Science in Dentistry Vol.39 No.2

Purpose : The purpose of this study was to develop the radiographic technique for detecting the demineralization which is known as indication of dental caries. Materials and Methods : This technique was based on the comparing of multiple radiographs which was irradiated by multiple X-ray spectra. For the meaningful comparing, the multiple radiographs were reconstructed to the dosimetrically consistent images using a standard material. The difference of resulting images of same target with multiple spectra represents the difference of response of material as regards the spectra. Results : We have found about 10% of demineralization of dental hard tissues particularly in the proximal region through the analyzing of differences. Conclusion : Most intriguing thing in this investigation was that the method to analyze difference shows us to an anatomic structure of dental hard tissues even if absolute values of optical density were excluded during the procedures.

경주지역 여고생의 초경과 체성장간의 관계

김준섭,권오구,박진석,오종수,박정현,박제식,안세한,이용환,서정호,신태섭,최영배,김덕수,이관,박수경 東國大學校醫學硏究所 2002 東國醫學 Vol.9 No.1

본 연구는 경주지역 1개 고등학교 3학년 여고생을 대상으로 초경 시작 전인 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레 수치와 초경 연령을 파악하여 여성의 초경이 빠를수록 체성장 속도의 변화가 있을 것이라는 가설을 기초로 두 요인간의 관련성을 파악하고자 시행되었다. 경주시 1개 여자고등학교 3학년생 총 317명에 대해 ㅊ경 나이, 초경시 심리 상태, 초경이 시작되었을 때의 상담 여부와 상담하였던 사람, 부모 신장과 초경전후의 식사 규칙성, 다이어트 경험, 수면시간, 스트레스, 음주/흡연 여부, 질병력 등에 대한 설문 조사를 시행하였고, 초등학교 4학년부터 고등학교 2학년까지의 키, 몸무게, 가슴둘레에 대한 정보는 건강기록부에서 확보하였다. 상기 대상자 중 건강기록부가 분실된 39명, 초경나이에 대해 응답하지 않았던 29명 및 결석 등으로 조사를 하지 못하였던 42명을 제외한 조사 대상자는 206명으로 선정하였다. 대상자들의 초경연령 평균값(Mean±SD)은 13.0±1.11이었고, 초등학교 4학년부터 고등학교 2학년까지의 초경 이후 신장 성장률은 감소하였으며, 초경연령이 빠른 군이 초등학교 때는 신장에 있어서 우위를 차지하나 고등학교에 오면서 신장은 비슷한 수준이 되었다. 초경후 1-2년 사이에 체중과 흉위의 증가율은 감소하였고, 초경연령이 빠른 군이 초등학교와 고등학교 사이에 체중과 흉위에서 모두 우위를 차지하였다. 본 연구의 결과는, 흔히 이차 성징의 시작 시점 혹은 사춘기의 시작 시점으로 보고있는 초경 연령이 청소년기의 성장과 밀접한 관련성이 있고, 특히 체중과 흉위의 성장 속도와 밀접한 관련성이 있음을 시사한다. To understand the onset of menarche in relation to changes in physical growth that take place during female adolescence, especially the changes in height and weight velocity. The 207 senior in one women high school of Kyongju were investigated in April 3 to 8, 2001. We collected the information, relation in the age at menarche, height & weight of parents, regularity of eating, and obesity diet, duration of sleeping, sickness & stress near age at menarche, by self-recording. The status of height, weight & chest circumference between the 4th grade of primary school and the junior of high school was collected by individual Health Record. The results were followed; The average age at menarche was 12.95±1.11 years old and the most frequent age of menarche is 13 years. After menarche, the velocity of height, weight and chest circumference were decreased. The most rapid group of menarche hold dominant position in height during elementary school. As time passed, they dont hold dominant position in height. The most rapid group of menarche get an advantage in the weight and the girth of chest after elementary school. The height of subjects is directly proportional to the height of their parents. These results suggest that the starting age at menestuation can be closely associated with physical growth and development.

應力波 放出信號의 周波數 스펙트럼 特性分析

朴正萬,朴勝玉,金洪錫 대진대학교 1993 大眞論叢 Vol.1 No.-

The effects of source, specimen and transducer frequency characteristics on the spectral content of acoustic emission signals were investigated. A substantial difference in the ball impact was detected. The fine structures of the signal spectra depended strongly on specimen resonances as well as transducer resonances. The frequancy spectra of the piezoelectric transducer, glass and PMMA plates were determined by a calibration system consisting of a breaking pencil lead and an optical probe. These transfer functions were used to calculate the source wave spectra due to dropping steel balls. The experimental source spectra were compared with theoretical predictions. The agreement between experiment and theory was good, although certainly not perfect.

원형 플레이트 형태에 따른 초음파 부상 장치의 진동특성에 관한 연구

정상화,최석봉,차경래,김현욱,김광호,박준호 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

In the semiconductor and optical industry the non-contact transportation is required for reducing the damages. The ultrasonic levitation is the solution of the problem. In this paper, the ultrasonic levitation system and 3 disk-type stator for levitation various object are proposed. The vibration modes of disks are analyzed with FEM and designed with the analysis results. The 3D vibration profiles of the disks are measured by Laser scanning vibrometer for verifying the vibration characteristics of the system. The amplitudes of the disks and the levitation heights of object are measured for evaluating the performance.

무가압 분말 충전 성형법을 이용한 SiC/C 복합체의 제조

박정현,임은택,성재석 연세대학교 산업기술연구소 1994 논문집 Vol.26 No.2

The new forming method which uses vibratiry powder packing followed by infiltration of binder solutions, Pressureless Powder Packing-Forming Method, was applied to the manufacturing of SiC/C composites. From the result of vibratory powder packing and binder infiltration experiment with various particle sizes, the abrasive SiC powder of which mean size is 40㎛ was selected because of its high packing density and no agglomeration in this forming method. Uniform green bodies with narrow pore size distribution and complex shapes could be easily formed by this new forming method. It was found that amorphous carbon was pentrated into green bodies by the impregnation-carbonization process. As a result, this forming method can be applied to the fabrication of SiC/C composite.

초정밀 광소자 정렬 스테이지의 구동 특성에 관한 연구

정상화,차경래,김현욱,최석봉,김광호,박준호 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

As the optical communication is introduced to the backbone network at first and becomes a general communication method of network, the demand of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, and WDM(Wavelength Division Multiplexing) element increases. The alignment and the attachment technology are very important in the fabrication of optical elements. In this paper, the driving mechanism of ultra precision stage is studied with the aim of optimal design of stage. The travel and the resolution of stage are investigated. The hysteresis of the stage is generated because of PZT actuator. The hysteresis and the inverse hysteresis are modeled in X, Y, and Z-axis motion. The input data of desired displacement to the stage according to input voltage is obtained from the inverse hysteresis equation. In the result of experiments with the input data, the errors due to hysteresis are well compensated.

칼라영상시스템에 의한 색재현 연구

朴勝玉,朴正萬,金洪錫 대진대학교 1993 大眞論叢 Vol.1 No.-

The tristimulus values of an object color are dependent on both the spectral power distribution of the illuminant and the surface reflectance of the object. Furthermore the physical factors that are relevant to color image processing include camera sensor spectral response and monitor phosphor power distributions. In this paper, we measured the chromaticity coordinates of monitor reproducing colors and compared them to actual color chips. Also the similar comparisons are made under changing illuminant conditions.

다채널 광정렬 장치에서의 다자유도 회전 스테이지 동작 특성에 관한 연구

정상화,차경래,김현욱,최석봉,김광호,박준호 한국공작기계학회 2005 한국공작기계학회 춘계학술대회논문집 Vol.2005 No.-

In recent years, as the demands of VBNS(Very high speed Backbone Network Service) and VDSL(Very high-data rate Digital Subscriber Line) increase, the development of kernel parts of optical communication such as PLC(Planar Light Circuit), Coupler, WDM elements increase. The alignment and the attachment technology are very important to fabricate the optical elements for communication. In this paper, the mechanism of rotational stage are studied. with the three different method and the results of them are applied to the design of the system. The performance test of resolution and travel is performed.

저온시동시의 유해배기가스 저감대책에관한 실험적연구

박경석,여정석 경희대학교 환경연구소 1994 環境硏究 論文集 Vol.5 No.-

It is a important facter to reduce automobile emissions. This paper deals with the estimation of catalyst characteristics for the automobile emission control by the electrically-heated catalyst converter. First of all, the after treatment method is required for LEV(Low Emissoin Vehicle) after FTP-75 mode limitation, the after treatment method is divided into two ways. Development of catalysis and reduction of catalyst activity time. Electrically heated monoliths have been designed and tested that are able to reach catalystic light-off temperature in less than 30 second using a conventional 12 volt electrical system. Gasoline vehicle emission data are presented that show substantial improvements in cold start HC and CO emissions by using resistance heating.

어린이 공공전문진료센터의 진료 역량: 상급종합병원과의 비교를 중심으로

오정윤,조수진,정진선,조진숙,박춘선 건강보험심사평가원 2022 HIRA RESEARCH Vol.2 No.2