Pollen Viability of Common Buckwheat (Fagopyrum esculentum Moench.) in in vitro Germination and its Application to Male Gametophyte Isolation

Woo, Sun-HeeㆍKeun-Yook ChungㆍHeung-Tae, KimㆍYong-Gu, ChoㆍHong-Sig, KimㆍBeom-Heon, Songㆍ Chul-Won, Lee and Seung-Keun Jong 忠北大學校 農業科學硏究所 2004 農業科學硏究 Vol.21 No.-

-본문참고-

점용접부의 피로강도 평가에 관한 연구

鄭鎭成,金英勳,李龍福,朴永勤 弘益大學校 科學技術硏究所 1997 科學技術硏究論文集 Vol.8 No.-

Spot welding has been used in the sheet metal joining processes because of its high productivity and convenience. In this study, effects of welding conditions on the fatigue life of spot welded joint and prediction of its fatigue life based on fracture mechanics theory of spot welded joint have been investigated. Fatigue tests were conducted with the tensile-shear specimens using cold rolled steel sheets. Fatigue life of spot welded joint was predicted and compared with experimental results. The experimental results are summarized as follows : 1. The static strength increased due to the increase in welding current, but the fatigue strength decreased while welding current being excessively increased. Therefore, the fatigue strength of spot weld was not proportional to the static strength. 2. Fatigue life of spot welded joint cannot be predicted accurately using the prediction methods proposed by Pook nor Findley. Therefore, it is necessary to consider stress index parameter method proposed by Kurath. 3. It is found that FEM analysis is powerful approach to evaluate the fatigue life of tensile shear spot welded joints with different geometry.

polyphenol류 및 그 함유생약의 MCF-7 cell에 미치는 항-증식 효과

정용자,곽홍근 慶星大學校 1999 論文集 Vol.20 No.2

The anti-proliferating effects of some plants on the MCF-7 cells were studied by the 3-[4,5-Dimethylthiazol-2yl]-2,5-diphenyl-tetrazolium bromide(MTT assay), to investigate the anticancer effect with some polyphenols. YKK, Acacia catechu, BioB and pine oil of them are showed a good anticancer effect. We also examined morphological changes on the MCF-7 cells in this process. The cells included in medium were investigated to be aggregated and destroyed slowly by treatment with those above. In case of YKK, Acacia catechu and pine oil, the cells are almost disappeared after 12 days in culture bottle.

급성하벽심근경색에서 전흉부유도 ST절 하강의 의의

정병천,배호상,곽동훈,김영태,배용학,황종현,임현주,류재근,조용근,채성철,전재은,박의현 慶北大學校 醫科大學 1997 慶北醫大誌 Vol.38 No.2

목적 : 급성하벽심근경색증 환자에서 심전도상 흔히 동반되는 전흉부유도 ST절 하강의 의의를 알아보았다. 방법 : 심근경색후 24시간에서 48시간에 얻은 심전도를 기준으로 52명의 급성하벽심근경색증 환자를 전흉부유도에서 ST절의 하강이 있는 군과 없는 군으로 나누었으며 심도자, 관상동맥조영술, 심초음파도 및 방사성 핵종을 이용한 좌심구혈율 측정 등을 시행하였다. 결과 : 1) 좌심실확장기말압은 전흉부유도에서 ST절의 하강이 있는 경우에서 16.9±5.33mmHg로 없는 경우의 11.0±4.02mmHg보다 유의하게 높았다(p<0.05). 그러나 운동량 및 좌심구혈을은 흥부 유도상 ST절의 하강이 있는 경우 7.6±3.0 METs 및 53.9±9.1%로 없는 경우의 9.1±2.7 METs 및 54.6±9.5%보다 낮았으나 통계적 유의성은 없었다(p=0.180, p=0.823). 2) 관상동맥조영술상 전흉부 ST절의 하강이 동반된 군에서는 유의한 좌전하행지나 좌회선지의 협착이 있는 경우가 60.9% 및 57.9%로 ST절의 하강이 없는 군에서의 34.5% 및 7.7%와 비교해 좌관상동맥에 협착이 동반된 경우가 많았다(p=0.050, p=0.001). 3) 관상동맥조영술상 세 혈관질환의 빈도는 흉부유도상 ST절의 하강을 보인 23예에서 10예로 ST절 하강이 없었던 29예중 2예에 비하여 유의하게 많았고(P=0.007), 단 혈관질환의 빈도는 ST절의 하강을 보인 군에서 23예중 5예로 ST절 하강이 없었던 29예중 17예에 비하여 유의하게 적었다(P=0.002). 두 혈관질환의 경우에는 각각 8예와 10예로 양군간에 유의한 차이가 없었다. 4) 흉부유도상 ST절 하강의 빈도는 단 혈관질환 22예 중 5예에서, 두 혈관질환 18예중 8예, 세 혈관질환 12예 중 10예에서 관찰되어 협착이 있는 관상동맥의 수가 많을수록 ST절의 하강이 나타나는 빈도가 많음을 보였다(p=0.00308). 그러나 흉부유도상 나타난 ST절의 하강을 모두 합하여 구한 ST절 하강의 합은 협착이 있는 관상동맥의 수와 통계적인 유의성이 없었다. 5) 심초음파도상 좌심실 하벽의 벽운동은 ST절 하강을 보인 군에서는 akinesia가 83.3%, hypokinesia가 11.1%, 정상 벽운동이 5.6%로, ST절 하강이 없었던 군에서의 dyskinesia가 3.6%, akinesia가 39.3%, hypokinesia가 25.0%, 정상 벽운동이 32.1%와 비교하여 ST절의 하강이 있는 군에서 유의하게 벽운동의 장애가 빈번함을 보였다(p=0.03891). 그러나 좌심실전벽, 측벽 및 중격부위에서는 유의한 벽운동의 차이가 없었다. 결론 : 급성하벽심근경색증 환자의 전흉부유도에서 ST절의 하강이 동반되는 경우 다혈관 질환의 가능성이 높으며 좌심실확장기말압이 상승되었고 운동능력은 감소되어 있었다. 또한 심초음파도상 좌심실하벽의 벽운동장애도 심하였다. 따라서 전흉부 ST절의 하강을 동반한 급성하벽심근경색증 환자는 전흉부유도에 ST절 하강이 없는 경우보다 예후가 불량할 것으로 생각되며, 보다 적극적인 치료가 필요할 것으로 생각된다. The purpose of this study was to determine the significance of precordial ST segment depression appearing during acute inferior myocardial infarction and to assess the correlation of that with angiographic finding. 52 patients were allocated into two groups based on the existence of precordial ST segment depression : 23 patients with ST segment depression and 29 patients without ST segment depression. The extent of coronary artery disease as well as the prevalence of significant stenosis (≥70%) in left anterior descending artery were more frequent in patients showing precordial ST segment depression than in patients not showing them (p=0.050) and the result were similar in cases of left circumplex artery (p=0.001). On echocrdiographic examination of left ventricular (LV) wall motion, it showed more severely decreased inferior LV wall motion in patients showing precordial ST segment depression than in patients not showing them (p=0.03891) even though the other segment of LV wall motion didn't show the statistical difference between both groups. The other cardiac parameters such as LVEDP, exercise amount (METs) and ejection fraction were tend to showing bad profile in patients with precordial ST segment depression. From the above results, we could deduce that patients with precordial ST segment depression have relatively large infarction or concomitant left coronary artery disease, so they need more caution and intensive theraphy.

중첩 방전을 이용한 CO₂레이저의 동작 특성 : 다중펄스 중첩을 이용한 long 펄스형 CO₂레이저의 펄스 형상 제어 Pulse shape control of pulse CO₂laser using multiple-pulse superposition

정현주,김근용,정용호,정종한,송건주,김희제 부산대학교 생산기술연구소 2001 生産技術硏究所論文集 Vol.60 No.-

본 연구에서는 PIC 원 칩 마이크로 프로세서 기술을 접목시켜, 저전압 측에서 2단 또는 3단의 회로를 능동적으로 중첩시킴으로써, 다양한 펄스폭을 가지는 고전압의 펄스형상을 만들었다. 이렇게 만들어진 다양한 중첩펄스를 현재 산업용 및 의료용으로 많이 사용되고 있는 CO2 레이저에 적용하여 각 단의 스위치의 트리거 지연시간에 따른 레이저 빔의 출력 특성을 고찰하였다. 그 결과 다양한 펄스폭을 가지는 레이저 빔을 얻을수가 있었고 특히, 3단 중첩회로에서 스위칭 지연 시간을 변화시킴에 따라 얻어진 레이저 펄스폭은 최소 약 4ms였고 최대 약 10ms였다. In this study, a variable pulse length, high duty cycle Pulse Forming Network(PFN) is constructed by time sequence. The power supply for this experiment consists of three switching circuits. Each switching circuit uses 2 mesh PFN, a charging circuit, a HV leakage transformer, and bridge rectifier on each transformer secondary. The PFN elements operate at low voltage and drive the primary of HV leakage transformer. The secondary of the transformer has a full-wave rectifier, which passes the pulse energy to the load in a continuous sequence. We investigated laser pulse width of pulsed CO2 laser as various delay time among three switching circuits. As a result, we can obtain various laser pulse width from about 4 to 10ms.

생체분해성 망막압정을 이용한 망막고정에 대한 실험적 연구

김용백,민병무,김창식,박근성,김승영,길숙종,조항진,이성복,노승무,송규상,강대영,조준식,양준묵,정경수,최선웅,이진호,김학용,인현빈 충남대학교 의과대학 지역사회의학연구소 1998 충남의대잡지 Vol.25 No.1

Biodegradable retinal fixation devices obtain mechnical fixation of the retina with desirable chorioretinal scarring and with the potential for local, sustained release of antimetabolites and steroids to inhibit proliferative vitreoretinopathy. We manufactured a biodegradable retinal tack with barb that was designed in order to prevent intrusion from implantation of retinal tacks. This study was carried to evaluate the efficacy for retinal fixation and the capability for sustained release of drugs with a newly designed biodegradable retinal tack Biodegradable retinal tacks were made of polymers of glycolic acids and were designed with barbs in a shape to prevent the disinsertion. Biodegradale retinal tacks are divided into 3 parts, a conical portion that is inserted into the sclera, a cylinder portion that remains in the vitreous, and a neck portion between the pin and the cylinder. The tapered conical end was manufactured to allow easy insertion through the retina and choroid into the sclera. A cylinder portion was manufactured with a tapered angle that fixes firmly into the orifice of 19 gauge spinal needle. A neck portion, 0.4 mm in diameter, was designed to prevent disinsertion from following implantation of retinal tack. The applicator was a 19 gauge spinal needle and its orifice was prepared to 15°angle to accept the tapered cylinder portion of the retinal tack. The retinal tacks, secured in the needles, were passed through the formed vitreous and inserted into the retina, choroid, and sclera and were released by pushing the internal needle, usually within 2-3mm of the medullary ray of the posterior rabbit retina A retinal tack was placed in each of 8 pigmented rabbit eyes. Slit-lamp biomicroscopy, indirect ophthalmoscopy and fundus photography were performed periodically from 1 day to 8 weeks after surgery. Eight eyes were enucleated and studied by light microscopy at 8 weeks. Biomicroscopic evaluation of the animals revealed edemas adjacent to the retinal surfaces immediately after insertion of the biodegradable retinal tacks in all the animals. These edemas disappeared after 1 week. The first noticeable change in the size of retinal tacks was shown after 2weeks. The size of the retinal tacks gradually got smaller, decreasing to about one-half at 4 weeks and about one-third at 8 weeks. All retinal tacks remained in inserted places without any movement for an 8 week period. On light microscopy, epiretinal proliferations were seen to extend into the vitreous cavity. Cellular capsules that lined the inner aspect of the scleral defect caused by tack insertion were found. However the adjacent retina had a normal cytologic appearance and architecture in all specimens. We manufactured a biodegradable retinal tack that is designed to prevent intrusion from implantation of retinal tacks. All biodegradable retinal tacks reduce in size with time, but no retinal tacks extruded from the inserted place. The newly designed biodegradable retinal tack can be used for retinal fixation and may be used as a vehicle for the introduction of pharmacologic agents to prevent the cellular events that promote proliferative vitreoretinopathy.

Frustration의 法理的 硏究

金龍熙,鄭照根 건국대학교 1974 學術誌 Vol.18 No.1

초음파현미경의 고주파 초음파 탐촉자를 이용한 코발트기 초내열합금강의 열화평가

박익근,조동수,김용권,임재생,김정석 한국비파괴검사학회 2004 한국비파괴검사학회지 Vol.24 No.5

V(z)곡선법을 이용한 코발트기 초내열합금강의 열화도 평가 유용성 유무를 고주파 초음파 탐촉자를 이용하여 실험적으로 검증 하였다. 코발트기 초내열 합금이 고온에서 장시간 노출되었을 때 일어나는 미세조직의 변화를 모사하기 위해서 인공열화를 실시하였다. 여로하에 미치는 초음파 음속의 영향을 고찰하고자 10MHz를 이용하여 펄스-에코법으로 종파의 음속을 측정하고 200MHz를 사용하여 V(z)곡선법으로 누설턴성표면파의 음속을 측정하였다. 두 초음파의 음속은 열화시간에 따라서 감소 하였다. 더욱이, 저주파수 종파의 음속변화는 거의 없었지만, 고주파수 누설탄성표면파의 음속변화는 열화시간에 따라서 최대 4.7%의 변화를 나타내었다. 열화에 따른 강도의 변화와 누설탄성표면파의 음속 변화는 양호한 상관관계를 나타내었다. 따라서 열화도 평가에 고주파 탐촉자를 이용한 초음파 현미경의 V(z)곡선법이 유용함을 알 수 있었다. The feasibility of V(z) curve method of scanning acoustic microscope using high frequency transducer was experimentally studied for assessment of the thermal degradation in Co-based superalloy. Thermal degradation was performed to simulate the microstructural changes in Co-based superalloy arising trom long term exposure at high temperature. Longitudinal wave velocity measured by pulse echo method using 10MHz transducer and leaky surface acoustic wave (LSAW) velocity measured by V(z) curve method using 200MHz transducer were measured to investigate the effect on thermal degradation. Ultrasonic velocity decreased as the aging time increased in both ultrasonic waves. Moreover, the low frequency longitudinal wave velocity decreased a little. Otherwise, the high frequency LSAW velocity drastically decreased up to a maximum of 4.7% at the aging time of 4,000hours. A good correlation was found between LSAW and Vickers hardness. Consequently, V(z) curve method of SAM using high frequency transducer could be a potential tool for assessing thermal degradation.

잣나무 풍매차대검정림의 계절별·가계별 생장과 동화생리 특성에 관한 연구

전상근,정동준,장용석 경희대학교 생명자원과학연구원 1999 硏究論文集 Vol.20 No.-

This study was carried out to investigate vegetative growth and assimilation physiological characteristics of Pinus koraiensis S. et Z.. The results can be summarized as follows: 1. Average values were 5.9±0.4m in height, 8.9±1.0cm in diameter of breast height, 12.0±3.2m^(2) in basal area and 46.5±14.2m^(3) per ha in volume all over 17 years. No. 20 Family showed excellent growth of 27% (11.3㎝) in mean diameter of breast height, 15%(6.8m) in mean height, 54%(15.8m^(2)) in mean basal area and 68%(79m^(3)) in mean volume than total mean value respectively. Otherwise Family No. 3 showed the badest growth of 16%(7.5㎝), 12%(7.9m^(2)) and 38%(29.0m^(3)) than total mean value. 2. The changes of seasonal photosynthesis rate by increasing luminous intensity showed that family No. 20 was the upper rank, family No. 10 was the middle and the lower rank was family No. 3. As the season has changed from winter to summer, the photosynthesis rate was increased. 3. Chlorophyll contents was increased from winter to summer, especially No. 20 family showed more contents than the others. 4. The weight of assimilation tissue(gr), length of needle(cm), width of needle(cm) and number of stoma of family No. 20 showed any more values than the others. 5. As the season has changed from winter to summer, the value of family No. 3 showed more than the others in water utilization rate all over season and values showed increasing tendency.

18年生 잣나무 次代檢定林의 家系別 毬果 着生量의 變異와 遺傳力

전상근,정동준,장용석 경희대학교 생명자원과학연구원 1998 硏究論文集 Vol.19 No.-

경기도 가평, 광주 그리고 충청북도 영동 지역에 조성한 잣나무 種子多産系 次代檢定林에 있어서 地域別, 家系別 18年生 着果量의 分散을 分析 檢討하고 遺傳力을 推定하였던 바 다으과 같은 結果를 얻었다. 1. 着果量은 지역별로 차이를 나타내여 가평 지역의 個體木當 平均看果數가 0.85個, 광주 지역이 0.87個, 영동 지역이 0.72個였으며, 3個 지역 전체 平均看果數는 0.82였다. 2. 3個 지역에 있어서 平均看果數가 가장 많았던 家系는 20番家系(0.96個)였으며 가장 看果가 적었던 家系는 21番家系(0.74個)였다. 3. 3個 지역 看果數는 變異에 가장 큰 影響을 미치는 分散要因은 plot내의 個體木間에 있었으며, 家系, 지역, Block 그리고 이들 要因들의 相互作用이 有意하게 영향하고 있었다. 그러나, 가계×지역의 상호작용은 중요 分散要因이 아니었다. 4. 看果數의 單一木遺傳力은 0.04~0.24, 家系遺傳力0.006, 家系遺傳力은 0.349였다. 5. 看果數에 대한 單一木 및 家系遺傳力은 지역에 따라 차이가 나타났으나 個體木當 平均看果數가 만았던 광주 지역이 높은 경향을 보였다. The objectives of this study were to analyze variation and to estunate heritabilities for cone production of 18-year-old open-polhated progenies of Korean White Pine in three different sites. The results were summarized as follows ; 1. Family, site, block, and interactions among these factors were significant source of variance for cone production. But the effects of family × site interaction were not relahvely large as compared with other source of variance. 2. Average values were 0.85 at Kapyung site, 0.87 at Kwangju site, 0.72 at Youngdong site and 0.82 overall three sites m mean of cone number per tree, respectively. 3. Family of No. 20 showed excellent value of 0.96 in mean of cone number per tree over all sites. 4. Individual-tree and family heritabilities were estimated 0.040∼24 and 0.16∼0.69 for cone production, respectively. For overall the sites, estunate of individual-tree heritability was 0.006 and that of family was 0.349 for cone production. 5. Heritability estunates vaned with testing site, and those for family were higher than for individual-tree.