고온 접촉식 탐상용 초음파 탐촉자 개발 및 평가

김기복,김병극,이승석,윤남원,윤동진,안윤국 한국비파괴검사학회 2003 한국비파괴검사학회지 Vol.23 No.1

고온(500℃) 환경에서 접촉식 탐상이 가능한 초음파 탐촉자를 개발하고 평가하였다. 고온용 탐촉자는 Curie 온도가 600 ℃ 이상인 bismuth titanate 계열의 압전세라믹 소자, 텅스텐 분말과 inorganic binder를 혼합한 후면재, 알루미나 튜브, 전면재, 하우징 등으로 구성되었다. 기본 공진주파수가 각각 1.04 및 2.08 ㎒의 2 종류 탐촉자를 제작하였으며 각종 고온용 커플런트의 온도특성을 시험하였다. 개발된 고온용 탐촉자를 이용하여 강재 시편을 대상으로 시편에서의 초음파 반사신호를 측정한 결과 시편의 온도가 증가함에 따라 반사신호의 크기는 감소하였다. 고온에서 반복측정 실험결과 500℃에서 연속적인 접촉식 초음파 탐상이 가능한 것으로 나타났다. Piezoelectric ultrasonic transducers for high temperature contact measurement were developed. These high temperature ultrasonic transducers (HTUT) consisted of bismuth titanate piezoceramic element whose Curie temperature is higher than 600℃, a backing material of the mixture of tungsten powder and inorganic binder, an inner alumina tube, a wear plate and a housing. The operational frequencies of the HTUT were 1.04 and 2.08 ㎒, respectively. Various commercially available couplant for high temperature were evaluated and compared. As a couplant for high temperature ultrasonic testing between HTUT and test specimen, gold epoxy was selected. The peak amplitude of pulse-echo signals from steel test specimen decreased with increasing temperature. The operational temperature of the HTUT reached up to 500℃ at which the continuous contact measurement was possible.

자궁내 발육지연이 있는 출생체중 2,500 g 이상인 환아의 주산기 예후에 관한 연구

송태복,조명숙,하진아,윤대석,김철홍,김윤하,최영륜 全南大醫大 2004 전남의대학술지 Vol.40 No.1

만성적 소음폭로가 근로자의 혈압에 미치는 영향

김복연,김천태,이중정,박홍진,김창윤,강복수 大韓産業醫學會 1996 대한직업환경의학회지 Vol.8 No.1

The question of an association between occupational noise exposure and blood pressure has important public health implications. The harmful effects of hypertension are well known and noise is considered the most pervasive problem of all occupational exposures in Taegu City, Korea. A cross-sectional study on the effect of long-term noise exposure on blood pressure was done for 276 noise exposed workers(203 male workers, 73 female workers). Long-term noise exposure was measured by cumulative noise exposure level and noise-induced hearing loss. Hearing loss = 500Hz+2×1,000Hz+2×2,000Hz+4,000Hz -------------------------------------- 6 Questionnaire was administered to the workers, which includes age, sex, occupational history on the noise exposure, habits on alcohol drinking and smoking, practice of regular exercises, family history of hypertension. Type A behavior, question on stress, height, weight and blood pressure were measured. Serum triglyceride and low density lipoprotein(LDL) were also measured. Audiometry was done in the closed booth at 1,000, 2,000, 3,000, 4,000, 6,000, 8,000, 1,000 and 500Hz in order. Multiple logistic regression analysis revealed that cumulative noise exposure level(p〈0.05), serum triglyceride(p〈0.01), age(p〈0.01) and family history of hypertension(p〈0.05) predict hypertension (systolic blood pressure : 160㎜Hg or above, or diastolic blood pressure : 95㎜Hg or above) in male workers. In female workers, serum triglyceride(p〈0.01), LDL(p〈0.01) and family history of hypertension(p〈0.05) were predictors of hypertension (systolic blood pressure : 160㎜Hg or above, or diastolic blood pressure : 95㎜Hg or above). As the number of female workers with hypertension was too small, the multiple logistic regression was done according to hypertension criteria of systolic blood pressure greater than or equal to 140㎜Hg, or diastolic blood pressure greater than or equal to 90㎜Hg. Based on this criteria, cumulative noise exposure level(p=0.055) and age(p=0.057) predict hypertension. It is suggested that long-term noise exposure which was calculated by cumulative noise exposure level was a significant predictor of hypertension in noise exposed workers.

제2형 당뇨병 환자에게 적용한 표준진료지침이 혈당, 당화혈색소, 당뇨지식 및 재원일수에 미치는 효과

김희승,윤건호,유양숙,오정아,송민선,신미옥,김경희,송복례 대한당뇨병학회 2002 임상당뇨병 Vol.3 No.1

연구배경 : 당뇨병 환자의 평균 재원기간을 단축시키고, 제한된 입원기간 내에서 질적인 면과 비용효과성을 고려한 총체적인 건강관리체계의 필요성이 요구됨으로써 생겨난 것이 당뇨병 표준진료지침(Critical Pathway: CP)이다. 현재 개발된 당뇨병 CP를 통한 진료가 환자의 당뇨병에 관한 지식을 개선시키고 이에 따라 장기적으로 당뇨병 환자의 혈당조절이 개선되었다는 과학적인 검증은 당뇨병 CP를 여러 병원에 정착시키기이전에 반드시 선행되어야 할 과제이다. 이에 본 연구는 2000년 3월부터 1년간 강남성모병원에 입원하는 당뇨병 환자를 대상으로 현재 개발된 1주일 CP를 적용한 실험군의 혈당, 당뇨병 관련 지식 및 재원일수가 대조군에 비하여 차이가 있는지를 조사하였다. 방법 : 1주일 CP를 적용한 실험군은 내과병동에 입원한 당뇨병 환자 89명이었고, 대조군은 기타병동에 입원한 당뇨병 환자 22명이었으며 CP를 적용하지 않았다. CP를 적용하기 전인 입원시에 실험군과 대조군의 공복혈당, 식후 2시간혈당, 당화혈색소 및 당뇨관련 지식을 측정하였고, 퇴원 시에 실험군과 대조군에게 공복혈당과 당뇨관련 지식을 재측정하고 재원일수를 파악하였다. 그리고 두 군에게 퇴원 3개월 후의 공복혈당, 식후 2시간 혈당 및 당화혈색소를 조사하였다. 결과 : 1) 실험군의 공복혈당은 입원 시 238.7: 1) 실험군의 공복혈당은 입원 시 238.7mg/dL에서 퇴원 시 139.4mg/dL로 감소하는 경향이었으나 퇴원 3개월 후에는 150.6mg/dL로 약간상승하는 경향을 보였다. 대조군은 입원 시 251.5mg/dL에서 퇴원 시 136.2mg/dL로 감소하는 경향이었으나, 퇴원 3개월 후에는 219.3mg/dL로 현저히 증가하는 경향이었다. 2) 실험군의 입원 시 식후 2시간 혈당은 312.5mg/dL에서 퇴원 3개월 후 248.5mg/dL로 감소하는 경향이었다. 대조군도 입원 시 식후 2시간 혈당이 300.1mg/dL에서 퇴원 3개월 후 262.5mg/dL로 감소하는 경향이었으나 실험군보다 감소의 폭이 적은 경향이었다. 3) 실험군과 대조군의 입원 시 당화혈색소는 각각 10.3%와 9.7%로 유의한 차이가 없었으나,퇴원 3개월 후 실험군은 7.5%로 대조군의 9.1% 보다 유의하게 감소하였다. 4) 실험군의 입원 시 당뇨지식 점수는 실험군이 12.1점 대조군은 12.0점으로 유의한 차이가 없었으나 퇴원 시는 실험군이 15.5점으로 대조군의 14.6점 보다 높은 경향이었다. 5) 재원일수는 실험군이 8.4일로 대조군의11.0일 보다 유의하게 적었다. 결론 : 따라서 당뇨병 환자를 위한 CP는 재원일수의 감소뿐만 아니라 환자의 자가관리에 대한 체계적인 교육과 개선의 기회를 가짐으로써 장기적인 혈당 조절의 향상을 도모할 수 있는 효과적인 방법이라고 생각한다. Background: The aim of this study was to examine the effects of the critical pathway for the admitted patients with type 2 dia betes me llitus on glycemic control, the knowledge on the disease, and the length of hospital stay. Methods: 89 diabetic in-patients were applied with the 1 week critical pathwa which was consisted of intensive education program for self-management of diabetes me llitus such as glucose monitoring, excercise prescription, diet control, self-a djustment of the drugs and so on. The results were compared with 22 diabetic inpatients who were treated with conventional way. We assessed the effects of critical pathway on the degree of glycemic control, the knowledge on the disease, and the length of hospital stay. Results: Although fasting and postprandial 2 hours blood g lucose levels did not showed sta tistically significantd ifference between critical pathway group and conventional group on discharge , HbA1c was significantly decreased in critical pathwa group compared with the conventional group (7.5±1.8% vs 9.1±2.6%) on 3 months after discharge . Knowledge on the disease tended to increase in critical pathway group compared with the conventional group on discharge. The Length of hospital stay was significantly decreased in critical pathway group compared with the conventional group (8.4±2.8day vs 11.0±3.9da ) Conclusion: These results showed that critical pathway for the patients with diabetes mellitus might be a usefulway for improving the long term glycemic control through motivation, enhancing the knowledge on the disase as well as reducing the length of hospital stay.

유방 침윤성 관암종의 CD44 발현도와 예후 인자들과의 관계

김정완,곽정식,손윤경,이승철,정운복 경북대학교 병원 1998 경북대학교병원의학연구소논문집 Vol.2 No.1

CD44 is a family of transmembrane glycoproteins involved in cell-cell and cell-matrix interactions. Expression of CD44 isoforms (splice variants) has been shown to be associated with poor prognosis in several human cancers. We evaluated the expression patterns of the CD44 isoform (CD 44 splice variant v6) in infiltrating ductal carcinoma of the breast by immunohistochemical and RT-PCR method. Paraffin embedded blocks from seventy-five cases of mastectomized samples were analyzed immunohistochemically using monoclonoal antibody against CD44v6. CD44v6 was detected in fifty-seven cases(76%) of the tumor samples. Adjacent normal myoepithelial cells and ductal epithelial cells revealed focal positive reaction to CD44v6. Thirty-two cases (80.0%) withe lymph nodal metastasis revealed overexpression of CD44v6 monoclonal antibody, but twenty-five cases (71.4%) without nodal metastasis also showed positive reaction to CD44v6 monclonal antibody, and there is no statisticallly significant value. Other prognostic factors of infiltrating ductal carcinoma, such as tumor size, histologic grade and hormonal receptors did not show any significant correlation with CD44v6 expression. The RT-PCR studies for 9 cases of infiltrating ductal carcinoma showed the same band patterns both in the normal and tumor tissues. From the above results, it is concluded that the expression of CD44v6 is not a valuable prognostic marker of infiltrating ductal carcinoma of breast.(Korean J Pathol 1997;31: 635~643)

고장시간 분포 추정을 위한 단일화된 접근 방법

김동석,윤복식,양경아 弘益大學校 科學技術硏究所 1996 科學技術硏究論文集 Vol.7 No.1

In this paper, we propose a simple and effective life distribution model based on piecewise Weibull failure rate function, called PWF model and introduce a simple method to estimate the parameters in PWF model based on the sequential partial F test and the least square method. All the procedures are computer coded and various numerical application exmples are also given. The results in this paper can be used to analyze failure time data almost automatically under quite general environment.

Phase-Type 분포의 근사화와 큐잉시스템 분석에의 응용

尹馥植,金貞姬 弘益大學校 科學技術硏究所 1995 科學技術硏究論文集 Vol.6 No.-

The Phase-type(PH) distribution, defined as a distribution of the time until the absorption in a finite continuous-time Markov chain state with one absorbing state, has been widely used for various stochastic modelling. But great computational burdens often make us hesitate to apply PH methods. In this paper, we propose a seemingly efficient approximation method for phase type distributions. We first describe methods to bound the first passage time distribution in continuous-time Markov chains. Next, we adapt these bounding methods to approximate phase-type distributions. Numerical computation results are given to verify their efficiency.

간호사가 지각한 수간호사의 리더십과 조직유효성에 관한 연구

김복미,이윤미,윤숙희,최은옥 대한간호행정학회 2007 간호행정학회지 Vol.13 No.3

Purpose: This descriptive study was designed to find out the relation between nurses' perceptions of leadership and organizational effectiveness. Method: The data was collected from nurses in 451, a tertiary hospital located in B city by means of structured questionnaires. The data was analysed by t-test. ANOVA, Pearson correlation coefficient. Results: The average age of the subjects was 29.1. Regarding the marital status, 68.1% were single. Regarding the nursing unit, 42.6% were working for the general surgical wards. The total period of clinical career was on average 73.7 months. Regarding the period in current ward, 51.0% were 1-less than 3 years. There was a positive correlation with transformational leadership, transactional leadership, job satisfaction, and organizational commitment, whereas the turnover intention had a negative correlation with transformational leadership and transactional leadership. Conclusion: The nurses' different perceptions of transformational leadership, transactional leadership, and organizational effectiveness have strong correlative relationships with each other. This finding suggests the importance of the head nurse's leadership in increasing organizational effectiveness.

매스매티카를 이용한 광대역 혼합트래픽의 분석

윤복식,김동석,성시영 弘益大學校 科學技術硏究所 1994 科學技術硏究論文集 Vol.4 No.-

Since the introduction of Mathematica in 1988, it has been succesfully utilized in various research fileds including mathematics and physics. In this study, we use the numerical and graphical power of Mathematica to analyze the voice traffic and the video traffic mixed with voice traffic under the B-ISDN environments. We adapt the fluid flow approximation as the basis of traffic modelling. The individual video source is modelled as a 3-state continuous time Markov chain. We present both numerical examples and Mathematica procedures in order to demonstrate the convenience of Mathematica as well as the validity of the model.

교정치료에 따른 사춘기 성장 아동의 상기도 폭경과 안면 성장 변화와의 관계 연구

김윤지,복규석,이규홍,황용인,박양호 대한치과교정학회 2009 대한치과교정학회지 Vol.39 No.3

본 연구의 목적은 아동에서 사춘기 성장 동안 기도의 변화가 안면 성장에 미치는 영향을 평가하는 것이었다. 9 - 11세(평균 10.7세)의 교정환자 36명을 대상으로 하여 초진 시(T1)와 치료 종료 시(T2)에 각각 측모두부방사선사진과 수완부 방사선 사진을 촬영하였다. 측모두부방사선사진상의 기도 폭경을 기준으로 하여 대상을 세 그룹으로 나누었다; 폭경이 좁은 그룹(AW-Narrow: 5.2 - 8.6 mm), 중간 그룹(AW-Medium: 8.9 - 11.5 mm), 넓은 그룹(AW-Wide: 11.7 - 16.0 mm). T1과 T2시기에 각 그룹 간의 안면 계측치의 차이를 비교하였으며 T1 - T2 사이의 계측치의 변화량을 각 그룹별로 비교하여 성장을 평가하였다. 각 그룹의 기도 폭경 증가량은 AW-Narrow, AW-Medium, AW-Wide group에서 각각 4.55 mm, 3.84 mm, 1.94 mm였으며 통계적으로 유의한 차이를 보였다. T1시기의 각 그룹 간의 비교에서 AW-Narrow group에서 다른 그룹에 비해 PFH가 유의하게 작은 값을 나타냈다. T1 - T2 사이의 성장 평가에서는 AW-Narrow group에서 다른 그룹에 비해 PFH/AFH, facial axis, ANS (T1 - T2), and Gn (T1 - T2)의 변화가 유의하게 큰 값을 보였다. 이 시기의 안면 성장 기간 동안 기도 폭경이 좁은 그룹에서 기도 폭경 및 안면 성장의 보상성 변화가 일어난 것으로 생각된다. 바람직하지 않은 안면 성장을 예방하기 위한 외과적 기도 처치를 고려할 때 자발적인 개선 가능성을 고려하여 좀 더 신중한 평가가 필요할 것으로 생각된다. Objective: The purpose of this study was to evaluate how airway changes influence facial growth during puberty in Korean children. Methods: Thirty-six patients aged 9 to 11 (mean age: 10.7 years) were selected. Cephalograms and hand-wrist x-rays were taken at pre-treatment (T1) and post-treatment (T2). The sample was divided into narrow (5.2 . 8.6 mm, AW-Narrow), medium (8.9 . 11.5 mm, AW-Medium), and wide (11.7 . 16.0 mm, AW-Wide) groups according to the airway width at T1. Cephalometric measurements at T1, T2 and growth from T1 to T2 were compared between groups. Results: The degree of increase in airway size in each group was 4.55 mm, 3.84 mm and 1.94 mm in the AW-Narrow, AW-Medium, and AW-Wide groups, respectively. Moreover, the differences were statistically significant. The significant smallest posterior facial height was found in the AW-Narrow group at T1. For the growth values from T1 to T2, the AW-Narrow group showed significantly larger values of PFH/AFH, facial axis, ANS (T1 - T2), and Gn (T1 - T2) than the AW-Medium group. Conclusions: The compensational changes in the airway width and facial growth were found in the narrow group. Surgical approach of the airway to prevent unfavorable facial growth in these years of age should be carried out, but with careful deliberation because these problems may be improved naturally.