초음파영상을 이용한 정상 교근의 평가

황형주,김규태,최용석,황의환 대한구강악안면방사선학회 2008 Imaging Science in Dentistry Vol.38 No.2

Purpose : To assess the internal echo intensity and morphological variability of masseter muscles on ultrasonography and to establish diagnostic criterion of estimation. Materials and Methods : Participants consisted of 50 young adults (male 25, female 25) without pathologic conditions and with full natural dentitions. Sonographic examinations were done with real time ultrasound equipment as Logiq 500 (GE Medical Systems, Seoul, Korea) at 3 parts according to lines paralleling with ala-tragus line as reference line. The thickness and area of masseter muscles according to reference line in cross-sectional images were measured at rest and at maximum contraction. The visibility and width of the internal echogenic intensity of the masseter muscles were also assessed and the muscle appearance was classified into 4 types. Data were statistically analyzed by paired t-test and x²-test. Results : 1. When comparing the thickness and area of masseter muscles concerning with gender, there was few significant difference between right and left sides, however, there were significant differences between males and females except for the greatest thickness of left side. 2. The changes of the greatest thickness and the area between rest and maximum contraction showed that the part of the least thickness manifested more increase at maximum contraction. 3. Each part the manifestations of the internal echogenic intensity of the masseter muscles were different depending on the locations. But there was no statistically significance. Conclusion : Changes of muscles thickness with contraction and internal echogenic intensity with locations showed great disparity within the masseter muscles, which will be diagnostic criteria for pathophysiologic and anatomic changes of masseter muscles.

배기가스 재순환에 의한 실린더 및 피스톤 마모에 미치는 영향에 관한 연구

황광성,김태규,정태상,김유영,하정호 진주산업대학교 산업과학기술연구소 2003 산업과학기술연구소보 Vol.- No.10

The effects of recirculated exhaust gas on the wear of cylinder liner, piston and piston rings have been investigated by the experiment with a two-cylinder, four cycle, indirect injection disel engine operating at 75% load and 1600 rpm spped. For the purpose of comparison between the wear rates of two cylinders with and without EGR, the recirculated exhaust gas is sucked into one of two cylinders after the soot among exhaust emissions is removed by an intentionally designed cylinder-type scrubber equipped with 6 water injectors(A water injector has 144 nozzles of 1.0 mm diameter), while only the fresh air into another cylinder. These experiments are carried out on the fuel injection at a fixed 15.3˚BTDC timing. It is found that firstly the mean wear amount of cylinder liner with EGR is more increased in the measurement positions of the second half than of the first and the mean wear amoount without EGR is almost uniform regardless of measurement positions, secondly the wear rates of the first and second piston ring(compression ring) thickness with EGR are more than twice, but the wear rate of oil ring thickness without EGR is more increased than that with EGR, and finally the wear rate of piston skirt with EGR is a little bit increased, but the piston head diameter is rather increased owing to soot adhesion and corrosion wear, and especially larger with EGR.

Cone beam형 전산화단층영상을 이용한 하악과두 위치의 연구

황형주,김규태,최용석,황의환 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.2

Purpose : To evaluate position of the mandibular condyle within articular fossa in an asymptomatic population radiographically by a cone beam computed tomography. Materials and Methods : Cone beam computed tomography of 60 temporomandibular joints was performed on 15 males and 15 females with no history of any temporomandibular disorders, or any other orthodontic or prosthodontic treatments. Position of mandibular condyle within articular fossa at centric occlusion was evaluated. A statistical evaluation was done using a SPSS. Results : In the sagittal views, mandibular condyle within articular fossa was posteriorly located at medial and central sections. In the coronal views, mandibular condyle within articular fossa was laterally located at central section. Mandibular condyles in the right and left sides were showed asymmetric positional relationship at medial, central, and lateral sections. Conclusion : Mandibular condyle within articular fossa in an asymptomatic population was observed nonconcentric position in the sagittal and coronal views.

전기 화상 환자의 수술 전 평가,고압손상과 저압손상 비교

황정원,이정기,전영태,강종만,오용석,노규정,김현철 대한정맥마취학회 2004 정맥마취 Vol.8 No.1

Artificial Neural Network for Modeling the Tensile Properties of Ferrite-Pearlite Steels: Relative Importance of Alloying Elements and Microstructural Factors

Tae‑Woon Hong,Sang‑In Lee,Jae‑Hyeok Shim,Myoung‑Gyu Lee,Joonho Lee,Byoungchul Hwang 대한금속·재료학회 2021 METALS AND MATERIALS International Vol.27 No.10

An artificial neural network (ANN) model was developed to predict the tensile properties as a function of alloying elementand microstructural factor of ferrite-pearlite steels. The input parameters of the model were composed of alloying elements(Mn, Si, Al, Nb, Ti, and V) and microstructural factors (pearlite fraction, ferrite grain size, interlamellar spacing, and cementitethickness), while the output parameters of the model were yield strength and tensile strength. Although the ferrite-pearlitesteels have complex relationships among the alloying elements, microstructural factors, and tensile properties, the ANNmodel predictions were found to be more accurate with experimental results than the existing equation model. In the presentstudy the individual effect of input parameters on the tensile properties was quantitatively estimated with the help of theaverage index of the relative importance for alloying elements as well as microstructural factors. The ANN model attemptedfrom the metallurgical points of view is expected to be useful for designing new steels having required mechanical properties.

PID제어를 이용한 Chamber의 냉방제어 시뮬레이션

정태상,황광성,김태규,김유영,정기환 진주산업대학교 산업과학기술연구소 2003 산업과학기술연구소보 Vol.- No.10

A cooling system of chamber is universally appliable with simple ON-OFF control algorithm. It has such disadvantages as having a delay for response time. To solve the above problem, we propose establishing the mathematical model of cooling system for chamber, simulating it with PID control algorithm and evaluating performance tests for control algorithm respectively.

cone beam형 전산화 단층촬영장치를 이용한 절치관의 연구

김규태,황의환,이상래 大韓口腔顎顔面 放射線學會 2004 Imaging Science in Dentistry Vol.34 No.1

Purpose : To investigate the anatomical structure of the incisive canal radiographically by a cone beam computed tomography. Materials and Methods : 38 persons (male 26, female 12) were chosen to take images of maxillary anterior region in dental CT mode using a cone beam computed tomography. The tube voltage were 65, 67, and 70 kVp, the tube current was 7 mA, and the exposure time was 13.3 seconds. The FH plane of each person was parallel to the floor. The images were analysed on the CRT display. Results : The mean length of incisive canal was 15.87mm±2.92. The mean diameter at the side of palate and nasal fossa were 3.49 mm±0.76 and 3.89 mm±1.06, respectively. In the cross-sectional shape of incisive canal, 50% were round, 34.2% were ovoid, and 15.8% were lobulated. 87% of incisive canal at the side of nasal fossa have one canal, 10.4% have two canals, and 2.6% have three canals, but these canals were merged into one canal in the middle portion of palate. The mean angles of the long axis of incisive canal and central incisor to the FH plane were 110.3˚±6.96 and 117.45˚±7.41, respectively. The angles of the long axis of incisive canal and central incisor to the FH plane were least correlated (r = 0.258). Conclusion : This experiment suggests that a cone beam computed radiography will be helpful in surgery or implantation on the maxillary incisive area.

Cone beam형 전산화단층촬영에 의한 흡수선량

이의태,김규태,최용석,황의환 대한구강악안면방사선학회 2007 Imaging Science in Dentistry Vol.37 No.2

Purpose : To measure the absorbed doses of cone beam computed tomography (CBCT), which is recently being more frequently used, and to compare them with those of panoramic radiography. Materials and Methods : To measure the absorbed doses of CBCT (PSR-9000N, Asahi Roentgen Ind. Co., Japan), we placed TLD chips on the skin regions above the parotid and thyroid glands, and on the dorsum of tongue in a dental head phantom. We used two image acquisition modes of the Dental and Panoramic modes of CBCT, which differed in the field of view. Also, panoramic radiographs (Auto IIIN, Asahi Roentgen Ind. Co., Japan) were taken to compare with the absorbed doses of CBCT. Result : In the Dental mode of CBCT, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 3.53, 3.13, and 0.36 mGy, respectively. In the Panoramic mode of CBCT, they were 9.57, 9.15, and 0.85 mGy, respectively. The panoramic mode showed higher absorbed doses than those of the Dental mode. In the panoramic radiography, the absorbed doses of the parotid gland, dorsum of tongue, and thyroid gland were 1.21, 1.19, and 0.16 mGy, respectively. And they were about 1/3 of the Dental mode and 1/9 of the Panoramic mode of CBCT. Conclusion : Absorbed doses of CBCT are higher than those of panoramic radiography, and dependent upon the field of view.

소아간질환자에서 Valproate 투여군과 Carbamazepine 투여군의 혈청 Leptin 및 Insulin농도에 관한 비교연구

고명진,황태규 인제대학교 백병원 2002 仁濟醫學 Vol.23 No.1

■ Objectives Valproate(VPA) is an effective anticonvulsant in many type of epilepsy but weight gain has been recognized as an adverse effect of valproate therapy and the mechanism is inevitable. To evaluate the effect of prolonged anticonvulsant therapy on obesity, we compared obesity Index, body mass index(BMI) and serum levels of leptin and insulin in both VPA and carbamazepine(CBZ) groups. ■ Methods and Methods Serum leptin and insulin levels were measured in 103 epileptic patients recieving VPA monotherapy(72 males. 31 females) and 66 patients recieving CBZ monotherapy(35 males, 31 females). Obesity index and BMI were measured by Inbody 3.0(Micromedic System Inc., U.S.A.) Serum samples were gained after overnight fast and were frozen -20degreesC until analyzed. Radioimmunoassay using Human leptin and insulin RIA kit (Linco Research co., St. Charles, U.S.A.) was performed. ■ Results 1) Body mass indicies were significatly higher in VPA group(19.62±3.75㎏/㎡) than CBZ group(18.10±3.17㎏/㎡)(p=0.009). 2) Serum leptin levels were significantly higher in VPA group(6.49±4.42ng/Mℓ) than CBZ group(2.27±2.77ng/Mℓ) (p=0.007). 3) Serum insulin levels were significantly higher in VPA group(23.28±19.47mU/L) than CBZ group(20.49±13.90mU/L) (P=0.03). ■ Conclusions Weight gain might be long-term complication of valproate monotherapy and correlate with the elevation of serum leptin and insulin levels.

Cone beam형 전산화 단층영상을 이용한 하악전치부 영양관의 연구

강정호,김규태,최용석,황의환 대한구강악안면방사선학회 2006 Imaging Science in Dentistry Vol.36 No.3

Purpose : To evaluate location, distribution, diameter, and length of the nutrient canals on mandibular anterior region using a cone beam computed tomography (CBCT). Materials and Methods : Mandibular CBCT was performed on 33 adults (18 males and 15 females) with no history of systemic disease, and any other dental surgery history. Location, distribution, diameter, and length of the nutrient canals on mandibular anterior region were radiographically evaluated. A statistical comparison was done by SPSS. Results : In the location and distribution of nutrient canals, they were found in 6.8% at labial portion above root apex, in 93.28% at lingual portion above root apex in 46.2% at labial portion below root apex, and in 53.6% at lingual portion below root apex. Nutrient canals at lingual portion above root apex were most frequently observed between central and lateral incisors, and those at labial and lingual portion below root apex were most frequently observed between central incisors. The mean diameters of nutrient canals were 0.54 mm at labial portion above root apex, 0.61 mm at lingual portion above root apex, 0.66 mm at labial portion below root apex, and 0.76 mm at lingual portion below root apex. The mean lengths of nutrient canals were 2.63 mm at labial portion above root apex, 3.74 mm at lingual portion above root apex, 4.51 mm at labial portion below root apex, and 6.77 mm at lingual portion below root apex. Conclusion : CBCT is useful device to evaluate the anatomical structure of nutrient canals on mandibular anterior region.