• 자원환경지질
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• 제22권2호
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• pp.103-115
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• 1989

The Tongyoung deposits are epithermal gold and silver bearing quartz-rhodochrosite vein type deposits of late Cretaceous. They occurs in the andesite and tuff breccia member called Gyeongsang basin. Four mineralizations can be distinguished at the mine based on macrostructures. From earlist stage to lastest stage they are: stage I, base-metal quartz vein; stage II, rhodochrosite vein (IIA) and Pb-Zn vein (IIB); stage III, barren quartz vein; stage IV, calcite-ankeritic rhodochrosite veins. Gold and silver mineralizations occur predominantly in the stage I and IIB. Electrum is closely associated with galena, sphalerite and pyrite, and has chemical compositions of 50.98-64.05 atom % Ag. Sphalerite contains 2.09-5.05 mol % FeS and 0.34-2.01 mol % MnS in the stage I, and 2.01-3.41 mol % FeS and 0.21-2.80 mol % MnS in the stage IIB. The FeS and MnS contents are in general correlated, and shows a characteristic zonal arrangement of electrum. It reveals rhat FeS contents of sphalerite which precipitated before electrum, gradually decreases in a grain during its deposition ranging from about 3.3 to 2 mol %. It may be considered from the above data that an increase of $fs_2$ caused by the oxidation of ore forming fluid is more important that the decrease of temperature.

• 한국가축번식학회지
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• 제11권1호
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• pp.33-41
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• 1987

The cycle of the seminiferous epthelia in the testis of matured Korean Native Cattle was divided into eight stages. The results were summarized as follows: 1. Type A spermatogonia a, pp.ared twice as many at stage 2 as compared to stage 1, while maximum numbers were the average of 2.8 at stage 2. The intermediate and Type B spermatogonia were found during the stage 3 to 8, stage 6 to 8, respectively. The leptolene primary spermatocytes were not observed during the stage 5 to 7, while the pachytene primary spermatocytes were shown the least in number at stage 4, the secondary supermatocytes could be seen only at stage 4 and the round spermatids were not observed at stage 3, 4. 2. The relative frequencies of the eight stages of the cycle of the seminiferous eptithelia were 24.9, 14.2, 19.0, 6.3, 3.7, 7.9, 10.3 and 13.9%, respectively. 3. Some of the nuclei of Sertoli cells transformed from the "parallel" type to the "perpendicular" type. This evolution took place from stage 1 to 5, when the number of "perpendicular" type nuclei reached a peak and the number was decreased in the rest of the stages.sed in the rest of the stages.

• 대한수의학회지
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• 제33권1호
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• pp.23-36
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• 1993

To investigate the cycle and relative frequences and the fine structure of seminiferous epithelia in mature Jindo dogs, histologic study was performed. The results obtained were summarized as follows; 1. Type A spermatogonia appeared approximately 1.6 times as many at stage II as compared to stage I while type In spermatogonia appeared small amount in stage III, IV and V. type B spermatogonia were found during the stage VI to VIII, though not detectable during stage I to V. The type B spermatogonia divided at stage VII to produce the preleptotene primary spermatocytes at stage VIII. The number of primary spermatocytes of the leptotene phase markedly increased during stage I to II, and the primary spermatocytes of the pachytene phase were shown the least in number at stage IV. The secondary spermatocytes could be seen only at stage IV. 2. The relative frequencies of each stage from stages I to VIII of the cycle of seminiferous epithelia were 31.6, 11.9, 10.0, 3.2, 8.2, 10.1, 11.7 and 13.2% respectively. 3. On electron microscopic observations, acrosomal vesicle of spermatids appeared larger though the bulk of germ cells were the morphologically same as those of the other animal species. Thread line structures light microscopically observed in the cytoplasm of Sertoli cell were the longitudinal orientation of mitochondria.

• 전력전자학회:학술대회논문집
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• 전력전자학회 2020년도 전력전자학술대회
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• pp.383-384
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• 2020

본 논문에서는 고승압이 가능한 2-Stage Boost 컨버터의 최대효율 운전을 위한 손실 분석을 수행한다. 2-Stage Boost 컨버터의 최대효율 지점 추정을 위해 앞단 Boost 컨버터의 출력 전압인 V_mid의 변동에 따른 2-Stage Boost 컨버터의 상세한 손실을 분석하며, 손실이 가장 적은 V_mid지점을 도출하였으며 실험을 통해 검증한다.

• 연구논문집
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• 통권25호
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• pp.77-90
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• 1995

For improving performance of heat pump system, researcher has adapted 2-stage economizer cycle and developed a high-efficiency screw compressor, new working medium(non-azeotropic mixed refrigerant) and counterflow heat exchangers operating with a small temperature difference. Target of this study is development of high performance heat pump system with the 2-stage economizer system using the non-azeotropic mixed refrigerant. For the purpose of excuting target, we constucted computer simulation programs, compared and examed various types of cycle and non-azeotropic mixture. Based on the results from computer simulation we selected optimum mixtures and reflected design and production process of performance test equipment with the 1-stage econmizer system. In order to accomplish the final target, design and production of the 2-stage economizer system, we performed pilot test using the 1-stage economizer performance test system and finally design and production of the 2-stage economizer system.

• International Journal of Oral Biology
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• 제36권4호
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• pp.195-201
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• 2011

Matrix metalloproteinases (MMPs) have been implicated in tissue development and re-modeling. Dynamic morphological changes of tooth germs reflect involvement of these enzymes during odontogenesis. The present study was performed to investigate expression and localization of MMP-2 and MMP-9, which have been known to have type IV collagenase activities, in rat tooth germs at different developmental stages. MMP-2 expression was increased gradually in the tooth germs from cap to crown staged germs at both transcription and translation levels. The localization of this molecule was detected in secretory ameloblasts and preameloblasts. The strong immunoreactivities were occasionally seen along the basement membrane between ameloblasts (or preameloblasts) and odontoblasts (preodontoblasts). However, weak reactivity was detected in odontoblasts and reduced enamel epithelium. The level of MMP-9 expression in the tooth germs was higher in cap stage than in crown staged germs at both transcription and translation levels. They were strongly expressed in both ameloblasts and odontoblasts. Even though reduced enamel epithelium after enamel formation and inner enamel epithelium at the cap stage exhibited weak reactivity, strong reactivity was detected in dental follicles and perifollicular tissues surrounding cap staged germs. These results suggested that MMP-2 may involve degradation of the basement membrane during hard tissue formation, whereas MMP-9 might be involved in remodeling of follicular tissues.

• Advances in pediatric surgery
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• 제11권2호
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• pp.99-106
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• 2005

Neuroblastoma treatment remains challenging, but treatment has become more effective due to the establishment of clinical and biological variables that determine prognostic risks. Initially, stage and age were the prime determinants of survival used in clinical practice. Risk-based therapy currently is the hallmark of neuroblastoma treatment. This study reviews one center's experience with the management of neuroblastoma. Sixty-three patients with neuroblastoma were treated from 1989 to 2003. All patients were graded according to the International Neuroblastoma Staging System (INSS) at diagnosis. There were 37 boys and 26 girls. The median age was 2.14 years (range, 33 days-10.2years). The primary site was the adrenal gland in 47, dumbbell shape extending into spinal canal in 6, retroperitoneum in 5, mediastinum in 3, and other sites in 2. The probability of 5-year overall survival (OS) and event free survival (EFS) were 46.7 % and 44.2 % by Kaplan-Meier method. According to INSS, there were stage 1 in 2 cases, stage 2 in 5, stage 3 in 12, stage 4 in 42, and stage 4s in 2. There were statistically significant differences in the survival rates between patients with stage1, 2 and stage 3, 4(P<0.05). For the stage 3 and 4, the extents of surgical resection, determined from the operative records and pathologies, were complete resection in 17 cases, minimal residual in 15, and partial resection 11, and the 5-year OS rate was 57.8, 51.4, and 13.6 %, respectively. There is a trend toward higher OS with more complete resection (P<0.05). We conclude that age and stage at diagnosis are prognostic factors, and complete excision of the primary tumor can provide better prognosis for patients with stage 3 and 4 neuroblastoma.

• International Journal of Precision Engineering and Manufacturing
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• 제8권2호
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• pp.64-69
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• 2007

Aerostatic planar XY stages are frequently used as the main frames of precision positioning systems. The machining and assembly process of the rails and bed of the stage is one of first processes performed when the system is built. When the system is complete, the 2D position, motion, and stage flatness errors are measured in tests. If the stage errors exceed the application requirements, the stage must be remachined and the assembly process must be repeated. This is difficult and time-consuming work. In this paper, a method for estimating the errors of a planar XY stage is proposed that can be applied when the rails and bed of the stage are evaluated. Profile measurements, estimates of the motion error, and 2D position estimation models were considered. A comparison of experimental results and our estimates indicated that the estimated errors were within $1{\mu}m$ of their true values. Thus, the proposed estimation method for 2D position and flatness errors of an aerostatic planar XY stage is expected to be a useful tool during the assembly process of guideways.

• Journal of Chest Surgery
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• 제26권6호
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• pp.463-469
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• 1993

From May 1986 to May 1992, 72 patients were diagnosed and operated for primary lung cancer, among them 65 patients were clinically evaluated at the department of Thoracic & Cardiovascular Surgery, Masan Koryo General Hospital. 1. There were 52 males 13 females[M:F=4:1], and 5th, 6th decade of life[72%] was peak incidence. 2. The preoperative diagnosis and its positive rate were sputum cytology 35%, bronchoscopy 47%, pleural effusion cytology 80%, and pleural biopsy 50%. 3. The classification histologic types were squamous cell cancer 71%, adenocarcinoma 17%, undifferentiated cell carcinoma 4.6%, and staging classification were Stage I 31%, Stage II 22%, Stage IIIa 26%, and Stage IIIb 20%. 4. The operative methods were lobectomy 52%, pneumonectomy 36%, and open biopsy 12%, and operability was 89%, resectability was 88%. 5. The postoperative complications developed 13 patients[22%], and operative mortality was 5%. 6. The overall actuarial survival rate was 1year 70%, 2year 42%, 3year 32%, 4year 26%, and 5year 22%, according to Stage 5year survival rate was Stage I 37%, Stage II 22%, Stage IIIa 3year 12%, Stage IIIb 2year 23%. And according to operative method lobectomy 23%, pneumonectomy 19%.

• 한국작물학회지
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• 제40권1호
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• pp.92-97
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• 1995

콩의 주요 생육기별 관수처리시간에 따른 생육양상과 감수요인을 구명하고자 콩의 생육기 $V_3(6월\;16일),\;V_6(6월\;29일),\;R_2(7월\;3일),\;R_4(7월\;29일)$ 시기에 관수시간을 6.12.24시간씩 명명 유지하여 비가림하우수내에서 pot시험한 결과를 요약하면 다음과 같다. 1. 개화기는 무처리 대비 $V_3{\cdot}V_6$생육기 관수처리에서 1일정도 지연되었다. 2. 성숙기는 무처리 대비 $V_6$시기 6~12시간 관수처리시 2~3일 조숙되었으나, $V_6$시기 24 시간과 $R_2{\cdot}R_4$시기의 관수처리는 2~8일 늦어지는 경향이었다. 3. $V_6와\;R_2$시기의 24시간 관수처리는 생장점이 고사하였으며 경장과 주경절수는 관수처리 시기가 빠르고 처리시간이 길수록 감소하는 경향이었다. 4. 내수는 처리시기가 늦고 처리시간이 길수록 감소되는 경향으로 $V_6$시기 24시간과 $R_2$ 6~24시간 $R_4$시기 6시간 관수처리는 16~26%, $R_4$시기 12시간 관수처리는 40%, $R_4$시기 24시간 관수처리는 60%씩 명명 감소되었다. 5. 수량은 관수시기가 늦고 관수시간이 길수록 감수되는 경향으로 무처리 대비 $V_3$시기 전처리와 $V_6$시기 6.12시간 처리까지 유의차가 없었으나 $V_6$시기 24시간, $R_2$시기 6.12 시간 및 $R_2$시기 6시간 관수처리는 27~36%, $R_2$시기 24시간 관수처리는 43%, $R_4$시기 12시간 관수처리는 53%, $R_4$시기 24시간 관수처리는 66%씩 명명 감수되었다. 6. 콩 생육기별 관수피해 정도는 $R_4>\;R_2>\;V_6>\;V_3$ 시기순으로 감수폭이 컸다.