소다라임유리에서 구형입자 충격손상에 미치는 가압조건의 영향

신형섭,오상엽 安東大學校 工業技術硏究所 2001 공업기술연구논문집 Vol.8 No.1

가압치구를 이용해 접촉압력을 가할 수 있는 실험장치를 개발하여 가압 구속조건이 구형입자 충격시 발생하는 충격손상의 영향을 조사하였다. 소다라임유리 (33×33×8mm)에 직경3mm인 WC와 Steel구를 각각 30~200m/s의 속도로 충격을 가하였다. 그리고 3가지 다른 조건, 즉 가압치구가 없는 경우, 가압치구가 있으며 압력 p=0㎫, p=200㎫ 를 가한 조건을 설정하였다. 입자충격으로 인하여 ring, radial 등과 같은 균열이 발생되었다. 시험편에 가한 접촉응력이 시험편 내부 응력장을 변화시켰다. 따라서 가압치구가 없는 시험편의 손상영역은 입자충격속도가 증가함에 따라 증가하였다. 200㎫의 접촉압력을 가한 시험편의 경우는 가압치구가 없는 경우에 비해 감소하였다. An experimental investigation was made, which comprise a pressing die, to evaluate the influence of pressing condition on the damage induced by a spherical impact. Steel and WC sphere in 3mm diameter impacted to soda-lime glass specimen with dimension of 33 x 33 x 8mm in the impact velocity range of 30m/s to 200m/s. Three different contact conditions were given for the impact damage evaluation, which are, the cases without pressing die, the cases of p=0㎫ and p=200㎫ with pressing die. The spherical impact had produced various kinds of damage such as ring cracks, cone cracks and radial cracks. The contact pressure applied to the specimen changed stress fields developed in the specimen which suppressed the structural bending of specimen and development of radial cracks. The extent of induced damage in the specimen with contact pressure of 200㎫ was reduced, as compared with the cases of without pressing die or with contact pressure of 100㎫.

Arachidonic acid 대사산물의 골흡수능

김형섭,오귀옥,장기완 대한구강생물학회 1991 International Journal of Oral Biology Vol.15 No.2

This experiment was performed to study the effect of the arachidonic acid metabolites(PGE_2, LTB_4, HETEs) on the bone resorption in the organ culture. The observed results were as follows: 1. PGE_2, at concentration of 10^-6M, increased ^45Ca release significantly after 72 hours of culture. 2. LTB_4 or HETEs, at all concentrations, had no effect on the bone resorption after 72 hours of culture. 3. LTB_4 or HETEs did not change the bone resorbing activity of PGE_2 bone resorption after 72 hours of culture.

치근이개부 감염에 관한 임상적 연구

김형섭 全北大學校 齒醫學硏究所 1985 전북치대논문집 Vol.3 No.1

The author studies the incidence, age, Glickman's classification of the maxillary and mandibular molars with furcation involvement by radiographic and clinical examination. The data for this study was 369 maxillary and mandibular molars of 40 patients (male 17, female 23) of Dentistry, J.N.U. Hospital. The results were as follows. 1. The mean average age of the patients was 43. The average number of the maxillary and mandibular molars in each patient was 4.5. 2. The incidence of furcation involvement for 185 maxillary molars and 184 mandibular molars was shown in 76 maxillary molars (40%) and 79 mandibular molars (42.9%). 3. The incidence of Glickman's classification of furcation involvement was shown in 73 Grade Ⅱ, 43 Grade Ⅲ, 25 Grade Ⅳ, 14 Grade Ⅰ.

IGBT PWM 컨버터 시스템의 제어 특성에 관한 연구

이진섭,백형래 조선대학교 에너지.자원신기술연구소 1999 에너지·자원신기술연구소 논문지 Vol.21 No.1

The problem of power factor and harmonics are occurred in converter system which used to SCRs and diodes a s power semiconductor devices. IGBT power device with self-commutation type was solved that problem, maintain the input line current with sinusoidal wave current of input power source voltage. It was estimated that improvement of transient state characteristics with feedforward compensator, added in the diode rectifier with single phase voltage type inverter was used to load. As a result it was verified that the transient state characteristics with voltage type PWM converter control was improved by simulation.

고기능 전력변환 이중데드비트 전류 제어기

이진섭,정해덕,백형래 조선대학교 에너지.자원신기술연구소 2000 에너지·자원신기술연구소 논문지 Vol.22 No.1

This paper describes a new digital control system based on the model state equations and a prediction method of the load current for PLW inverter with DC link. A new technique used dead beat theory to obtain a sinusoidal PWM inverter output voltage with LC filter has been presented. The dead schemes possess one sample delay in theses controlled signal which can compensate by prediction of the reference wave of the load current at next sample time. Load current prediction which has quick response is applied to compensate the random and high frequency components. This proposed control inherently is verified vary good sinusoidal output wave synthesis of voltage and current, providing accurate phase positioning for various load and excellent transient response. The experimental implementation of the system uses a real time TMS320C31 DSP(Digita1 Signal Processor)based digital controller.

아닐링처리에 따른 NbTi초전도 선재의 RRR거동에 미치는 피로손상의 영향

신형섭,오상엽 安東大學校 工業技術硏究所 2000 공업기술연구논문집 Vol.7 No.1

9본으로 구성된 Cu-Ni/NbTi/Cu 복합선재의 RRR에 대한 피로손상의 영향을 연구하기 위하여 상온에서 피로시험을 실시하고, 12K에서 잔류저항을 측정하였다. 피로시험은 아닐링열처리한 초전도 선재를 사용하였다. 피로시험시 소선간의 fretting이 발생한 가능성이 높았지만, 9본 Cu-Ni/NbTi/Cu 복합선재의 피로시험을 통하여 S-N선도를 구살 수 있었다. 피로시험후 NbTi소선의 저항을 측정한 결과, 아닐링한 선재의 RRR값이 처녀재보다 3배가 높았으나, 피로 반복수가 증가함에 따라 격자결함과 Cu안정화재 내부에 전위와 같은 손상의 누적 원인으로 RRR값이 감소하였다. In order to investigate how the fatigue damage influences on the RRR of a 9 strand Cu-Ni/NbTi/Cu composite cable, the fatigue test at room temperature and the residual resistivity measurement test at 12K were carried out. The annealing treated superconducting cable was used in the fatigue test. A conventional S-N curve could be obtained through the fatigue test of the 9 strand Cu-Ni/NbTi/Cu composite cables, despite a high possibility of fretting among strands. From the resistivity measurement of a NbTi strand after fatigue tests, it was found that the RRR for annealed cables was 3 times higher than that for as received one, but with increasing the repeated number the RRR decreased which was resulted from the accumulation of damage such as lattice defects and dislocations within the Cu stabilizer.

연속공정시스템의 고속 고정도 장력제어시스템

이진섭,백형래,이상일 조선대학교 에너지.자원신기술연구소 2001 에너지·자원신기술연구소 논문지 Vol.23 No.1

This paper deals with the tension control of state feedback control for continuous processing line. At the starting point of entry section, for example, a unwinder named pay off reel unwinds the material maintaining constant tension and line speed. Speed and torque characteristics state is variance during acceleration and deceleration period. In simulation roll diameter variation and inertia variation are considered. It becomes clear that the proposed tension control system has high accuracy performance.

忠北地域의 배추좀나방 系統에 대한 殺蟲劑에 관한 硏究

金舜燮,李炯來 충북대학교 농업과학기술연구소 1993 農業科學硏究 Vol.10 No.2

The experiment was carried out by the spray method to investigate the insecticidal resistance of the susceptible and the collected strains of the diamondback moth, DBM(Plutella xylostella L.)in Chungbuk Province. The results are summarized as follows. 1.In Chlorpyrifos, the LC50 values(ppm) of the susceptible(s-strain), Cheongwon, Ockcheon, Boeun, Jungwon, Koesan, Yeongdong and Jewon strains were 11.5, 18.2, 39.8, 42.2, 141.6, 154.0, 173.8, and 224.9, respectively. The resistance of the Jewon strain was 19.6 times greater than that of the s-strain. 2.In Methomyl, the LC50 values(ppm) of the susceptible, Cheongwon, Boeun, Jewon, Koesan, Jungwon, Ockcheon and Yeongdong strains were 0.94, 57.1, 83.0, 97.4, 148.6, 240.8, 286.9 and 512.4, respectively. The Yeongdong strain showed the highest resistant level among the collected strains. The LC50 values of the Yeongdong, Ockcheon, Jungwon, Koesan and Jewon strains were at least 100 times greater than that of the s-strain. 3.In Carbaryl, the LC50 values(ppm) of the susceptible, Ockcheon, Boeun, Koesan, Yeongdong, Jewon, Cheongwon, and Jungwon strains were 36.3, 69.6, 141.3, 256.3, 269.9, 884.9, 2224.8 and 34 14.3, respectively. The LC50 values of the Jungwon strain was 94.1 times greater than that of the s-strain. 4.In Deltamethrin, the LC50 values(ppm) of the susceptible, Boeun, Ockcheon, Cheongwon, Yeongdong, Jewon, Jungwon, and Koesan strains were 9.3, 23.8, 30.9, 31.4, 52.0, 55.9, 67.4 and 99,6, respectively. The LC50 value of the Koesan strain was 10.7 times greater than that of the s-strain. 5.In Fenvalerate, the LC50 values(ppm) of the susceptible. Yeongdong, Jungwon, Boeun, Cheo-ngwon, Koesan, and Jewon strains were 9.7, 44.4, 72.1, 78.5, 92.0, 186.8 and 245.1, respectively. The LC50 value of the Jewon strain was 25.2 times greater than that of the s-strain. 6.In Cartap, the LC50 values(ppm) of the susceptible, Ockcheon, Koesan, Yeongdong, Jungwon, Boeun, Jewon, and Cheongwon strains were 18.5, 24.3, 25.8, 119.3, 128.5, 130.2, 132.6 and 384.0, respectively. The LC50 value of the Cheongwon strain was 20.7 times greater than that of the s-st-rain.

유리자가 치은 이식술을 이용한 부착치은 확대의 증례보고

김형섭 全北大學校 齒醫學硏究所 1983 전북치대논문집 Vol.1 No.1

To increase the attached gingiva and deepen the vestibular fornix, the author applied to use free gingival autograft procedure in the right premolar area in 43 years old male patients without systemic complication. Donor site for free gingival autograft procedure was determined to obtain upper palatal mucosa with Omar Paquett knife. Positioned the autograft and adaptedit firmly to the recipient site. Used a minimum number of sutures to avoid unneccessary tissue penetration. Grafted mucosa was covered with COE-pak for lweek and clinical evaluation was performed until 2 weeks after surgery. After postoperative 2 weeks, grafted mucosa was seen relatively normal gingival color and appeared like attached gingival architecture on clinical observation. During postoperative period, patient was no complain of the surgical site and periodontal eviornment of the patient was improved.

치주질환에 있어서의 조직파괴인자 및 억제약물에 대한 연구

김오환,김형섭,오귀옥 대한구강생물학회 1988 International Journal of Oral Biology Vol.12 No.2

Arachidonic acid(AA) metabolites are known to play an important role in the development of inflammation and pathogenesis of periodontal disease. The bone resorbing activity of PGE_2 and elevated level of prostaglandins and thromboxane in inflamed gingiva, which are cyclooxygenase(C) products, has been well documented. However, since recent studies provide evidence that gingival tissue metabolizes AA mainly through lipoxygenase(L) pathway, we have started this study to show the exact profile of AA metabolism in gingival tissue. Fourteen individual periodontal pocket tissue(PPT) samples were obtained from patients with advanced periodontitis and incubated separately with ^14C-AA(0.2μCi). The tissue lipid extracts were separated by means of thin layer chromatography(TLC), and analyzed by means of autoradiography and TLC analyzer. Our work show that ^14C-AA metabolism in PPT is mainly via the L pathway(L products/C products=6.17) and that 12-HETE & 15-HETE(55.73% of total formed metabolites), to a lesser extent 5-HETE(6.21%), are the major L products formed. C products thromboxane B_2 (4.32%), 6-keto-PGF_1α & PGE_2 (4.42%) were also detected in much smaller amounts than L products. Indomethacin well-known C inhibitor, also inhibited L as well as C, that is the result similar to the reports of Paajanen et al.(1982) and Lessard et al.(1986). This phenomenon is being further investigated by use of partially purified L system.