사출압축성형 CAE 를 이용한 플라스틱 광학렌즈의 웰드 저감 기술

공기환(G. H. Gong),곽태수(T. S. Kwak),정종교(J.K. Jeong),신건휘(G. H. Shin) 한국정밀공학회 2016 한국정밀공학회 학술발표대회 논문집 Vol.2016 No.5월

광학렌즈의 사출압축성형에서 오버플로우를 이용한 웰드라인과 복굴절 저감

공기환(Ki-Hwan Kong),이진효(Jin-Hyo Lee),강병욱(Byung-Ook Kang),곽태수(Tae-Soo Kwak) 한국기계가공학회 2018 한국기계가공학회지 Vol.17 No.1

This study has focused on the weld-line and birefringence reduction of a plastic optic lens using over and CAE analysis in injection compression molding. A concave lens, which has a thin thickness in the center and a large difference in thickness between the center and the periphery, often causes weld-line defects during injection molding. CAE analysis has been applied to optimize the overflow design in order to reduce the weld-line defects and the polarization defects. To reduce the weld line and birefringence defects, overflow design and application using CAE analysis show that the measured birefringence values of the specimens before the overflow application were 46.8㎚ and 36.9㎚, and the values after the over-flow application were 13.6㎚ and 14.0㎚. From the experimental results, it is confirmed that birefringence is greatly improved when overflow is applied.

사출압축 성형에서 압축시작 시간과 사출속도가 Weld 형성에 미치는 영향

공기환(G. Gong),곽태수(T. Kwak),신건휘(G. Shin) 한국생산제조학회 2016 한국생산제조시스템학회 학술발표대회 논문집 Vol.2016 No.04

절제수술로 치료한 자궁경부 상피내암과 미세침윤암에서 세포진과 조직진의 비교평가

윤수철 ( Soo Cheol Yoon ),공기환 ( Gi Hwan Gong ),정선안 ( Sun An Jung ),최영석 ( Young Seuk Choi ),유기성 ( Ki Sung Ryu ),한구택 ( Ku Taek Han ),나종구 ( Jong Gu Rha ),이헌영 ( Hun Young Lee ),김수평 ( Soo Pyung Kim ) 대한산부인과학회 1997 Obstetrics & Gynecology Science Vol.40 No.12

We evaluated 221 patients who were preoperatively diognosed as carcinoma in situ(CIS) and microinvasive carcinoma(MIC) from Jan. 1988 to Dec. 1995 at the Department of Obstetrics and Gynecology, St. Mary`s hospital, Catholic University Medical College. The data gained from 221 patients with sucessful tollow-up were thoroughly reviewed to determine the proper diagnosis and treatment model. They were treated by conization, total abdominal hysterectomy or type II hysterectomy. The final diagnoses of 127 patients who got one cytologic diagnosis at local clinic or our hospital were 80 CIS, 45 MIC and 2 mvasive carcinomas. In cytology, 47 case(58.8 %) of 80 CIS showed abnormal findings as class III(30 %), IV(22.5 %) and V(6.3 %). In 45 MIC, 33(73.3 %) cases showed abnormal finding as class III(35.6 %), IV(28.9 %) and V(8.9 %). 94 patients who got cytology twice at the local clinic or our department were finally diagnosed as 72 CIS and 22 MIC. By repeating cytology, we could reduce false positive rate, 12.5 % in CIS and 4.5 % in MIC, however repeat cytology had little diagnostic value. In comparison of colposcopy guided biopsy(CGB) to non-colposcopic blind biopsy, CGB was more predictive. In CIS, the accurate diaganosis rates were 77.6 %(52/67) in blind biopsy and 88.8 %(95/124) in CGB. In MIC, the accuracies were 71.8%(28/39) in blind biopsy and 100 %(33/33) in CGB. So colposcopic evaluation with optional conization was essential for pooper diagnosis and treatment. There were unfavorable histologic findings: vaginal extension(n=4; 1.8 %), lymphovascular space involvement(n=4; 1.8 %), perineural invasion(n=1; 0.5 %) and occult invasive cancer(n=2; 1.8 %). So conservative treatment and local destructive therapy were potentially dangerous in CIS and MIC and should be performed after precise evaluation in selected cases. For proper diagnosis and treatment, cytologic evaluation had limited clinical values and CGB with optional conization was needed.

유도분만 직전 절경부에서 검출된 fetal fibronectin의 임상적 의의

이영,김창이,김수평,최영석,최소영,이형근,김진범,공기환,안상복 대한산부인과학회 1998 Obstetrics & Gynecology Science Vol.41 No.1

Objective: Our purpose was to determine whether the detection of fetal fibronectin in cervicovaginal secretions of woman before labor induction reflected readiness of the uterus and ultimately the ease of induction of labor. Methods: We studied 52 women undergoing induction of labor by means of prostaglandin E₂after 37 weeks` gestation. A Dacron polyester swab specimen was first taken from endocervix and posterior vaginal fornix for assessment of the presence of the fetal fibronectin. The cervix was then assessed by digital vaginal examination and scored with modified Bishop score. The cervicovaginal fetal fibronectin was measurde quantitatively by fetal fibronectin immunoassay (Adeza Biomedical, Sunnyvale, California, USA). The results were considered positive when specimens had a fetal fibronectin concentration above 50ng/ml. Induction of labor was considered to be successful if vaginal delivery occured within 24 hours after the application of the PGE₂ tablets. We compared positive result for fetal fibronectin wtth high Bishop score(≥5) as a predictor of successful labor. Results: 9 samples were excluded due to blood contamination. Total 43 samples were studied. 21 had positive results for fetal fibronectin and 22 had negatibve results. 25 were delivered within 24 hours of the application of PGE₂. Of the women inthis group, two were delivered by cesarean section. The results were as follows: 1. Women with fetal fibronectin-positive cervicovaginal secretions had a significantly shorter(10 hours 57 minutes vs 29 hours 01 minutes, P=0.0001) interval between prostaglandin application and delivery, and needed a significantly lower(1.1:2, P=0.007) numbers of PGE₂tablets than did fetal fibronectin-negative patients. 2. Bishop`s score was not different in interval between prostaglandin application and delivery(group with high score 20 hours 09 minutes vs group with low score 16 hours 13 minutes, p = 0.5850), and numbers of PGE₂tablets(1.5 vs 1.51, P=0.855). 3. Patients with fetal fibronectin-positive cervicovaginal secretions were more delivered within 24 hours than Patients with fibronectin - negative group(fetal fibronectin positive group: 19/21, 90.5% vs fetal fibronectin negative group: 6/22, 22.3%). 4. The rate of unsuccessful induction of labor and operative delivery was highest in women with fibronectin-negative cervicovaginal secretions and olw Bishop`s score(7/8,87.5%) 5. Multiple logistic regression shows that only the fetal fibronectin enzyme immunoassay provides an independent statistically significant predictor for purposes of predicting vaginal delivery within 24 hours(P=0.0025, adjusted odds ratio 25.33). 6. The positive value of cervicovaginal fetal fibronectin was more predictive of successful labor induction than Bishop score ≥ 5(sensitivity 82.6%: 17.4%, positive predictive value 95.0%: 57.1%). Conclusions: Positive cervicovaginal fetal fibronectin before labor induction may be a useful biochemical predictor for successful induction of labor.

한국 여성의 자궁경부이형증 환자에 있어서 Retinoic Acid 투여 후의 HPV Titrationd의 변화

김승조,남궁성은,안웅식,이형근,정선안,김진범,공기환,안상복 대한산부인과학회 1998 Obstetrics & Gynecology Science Vol.41 No.1

Retinoids have been recognized as a family of molecules capable of profound impact on many biologic functons, also known to possess antiproliferative, differentiative, and immunomodulatory properties. However, only recently have laboratory and precoinical and clinical oncology reseatch made this knowledge immediately relevant to the problem of malignancy. Cervical cancer is thr second most common malignancy in women worldwide and remains a significant health problem in women. While the natural history is well known, little is known of the pathobiology of cervical carcinogenesis, prevention of cervical cancer and its precursors are impprtant objectives. To assess the effect of 13-cis-retinoic acid(13-CRA) in the rteatment of 13 chronic cervicitis and 52 cervical intraepithelial neoplasia, we examined lower and high risk Human Papilloma Virus(HPV) titration(using Hybrid Capture system) and colposcopic and cervicographic examination before and after rteatment with 13-CRA 1㎎/㎏ for 4 to 12 weeks. The following results were obtainted : 1. The age distributon of patients was between 23 years and 64 year, average 36.6 years old. 2. Histology revealed the chronic cervicitis 13 cases, mild dysplasia 18 cases, moderate dysplasia 18 cases and severe dysplasia 16 cases, total 65 cases. 3. Among these groups the expression rates of high risk Human Papilloma Virus(HPV 16, 18) were 9 of 13 cases(69%) in chronic cervictis, 7 of 18 cases(39%) in mild dysplasia, 9 of 18 cases(50%) in moderate dysplasia and 12 of 16 cases(75%) in severe dysplasia, overall expression rate was 37 of 65 cases(57%) 4. After treatment, decreasing changes of HPV titration(high risk)vy hybrid capture system were 6 of 9 cases(66%) of chronic cervictis, 3 of 7 cases(43%) of mild dysplasia, 7 or 9 cases(77%) of moderate dysplasia, 8 of 12 cases(75%) of severe dysplasia,overall decreasing rate was 25 of 41 cases(61%). From this stucy, high risk HPV titration were decreased after treatment winh 13-CRA in prtients with cervical intrapithelial neoplasia, it revealed some potentiality to interrupt multistep caricnogenesis by possibly down regulation of gene product(E6, E7) produced by HPV infection.

침윤성 복막이식을 동반한 난소의 경계성 표면 유두종 IIIc기 1 예

김흥기,김창이,김수평,김용욱,류순원,전준연,공기환,송영훈 대한산부인과학회 1997 Obstetrics & Gynecology Science Vol.40 No.9

The serous borderline tumors(SBTs) are divided into 3 groups, typical SBT with nonin-vasive implants, SBTs with invasive implants, and a recently described tumor, desinated mic-ropapillary serous carcinoma(MPSC). These tumors are associated with extraovarian implants, espicially peritoneum. Invasiveness of implants has prognostic significance in disease progre-ssion and recurrence. Micropapillary serous carcinoma and SBTs with invasive implants sho-uld be classified as carcinoma and treated accordingly. We report a case of borderline malign-ant ovarian surface papilloma with invasive peritoneal implant.

자궁경부암 환자에서 광범위 자궁적출술 전후의 방광과 요도의 해부학적 형태에 대한 연구 - 금속성 염주상 연쇄 요도방광 조영술을 이용한 분석-

송승규,박태철,김수평,김은중,김사진,이귀세라,이형근,허수영,김진범,공기환,안상복 대한산부인과학회 1998 Obstetrics & Gynecology Science Vol.41 No.1

This present study was undertaken to evaluate the chacteristic anatomic configuration of bladder and urethra in parients with cervical cancer before and after radical hysterectomy. From July 1994 to December 1996, metallic beaded chain urethrocystography was conducted in 33 patients with cervical cancer before and after radical hysterectomy at Holy Family hospital. The results were as follows. 1. After radical hysterectomy, posterior urethrovesical angles at rest and strain were significantly increased(P = 0.0004 at rest, P = 0.0016 at strain) and posterior urethrovesical junction at rest and strai were significantly descended(P = 0.004 at rest, P = 0.0024 at strain). 2. Postoperative urethral inclination angle at rest was greater than before radical hysterectomy(P = 0.002), but postoperative urethral inclination angle at strain was not increased statistically(P > 0.05). From these results, we concluded that stress urinary incontinence after radical hysterectomy is the results of anatomically defective supports of urethrovesical junction and urethra. We must consider a proper surgical method to prevent stress urinary incontinnce and anatomical defect of urethrovesical junction.