• 조명전기설비학회논문지
• /
• 제26권4호
• /
• pp.82-87
• /
• 2012

In this paper, flashover characteristics of air in the vertical arrangement of cylinder-shaped rod and plane gap in the case of combustion flame on the plane electrode were examined under the application of a.c. and d.c. high-voltages. In order to investigate the effect of propane flame on the flashover characteristics of air, flashover voltages in accordance with the variation of the gap length and the horizontal distance between the flame and the high-voltage rod electrode were measured. As the result of the experiment, flashover voltages in the presence of the flame were substantially lowered than those in the absence of flame, and the polarity effects with the d.c. voltages on appeared owing to the flame. Flashover voltages of air were increased in the proportion of the gap length and the horizontal distance in the case of both a.c. and d.c. voltages, but the flame was extinguished by such corona wind that was produced from the rod electrode when the gap length and the horizontal distance reached to a certain degree.

• 대한치과교정학회지
• /
• 제50권4호
• /
• pp.258-267
• /
• 2020

Objective: This study aimed to analyze the correlation of horizontal and sagittal planes used in two-dimensional diagnosis with lip canting by using three-dimensional (3D) analysis. Methods: Fifty-two patients (25 men, 27 women; average age: 24 years) undergoing treatment for dentofacial deformity were enrolled. Computed tomography images were acquired, and digital imaging and communication in medicine files were reconstructed into a 3D virtual model wherein horizontal and sagittal craniofacial planes were measured. Subsequently, the correlations of lip canting with these horizontal and sagittal planes were investigated. Results: The mandibular symmetry plane, the occlusal plane, Camper's plane, the mandibular plane, Broadbent's plane, and the nasal axis plane were correlated with the amount of lip canting (Pearson's correlation coefficients: 0.761, 0.648, 0.556, 0.526, 0.438, and 0.406, respectively). Planes associated with the lower part of the face showed the strongest correlations; the strength of the correlations decreased in the midfacial and cranial regions. None of the planes showed statistically significant differences between patients with clinical lip canting (> 3°) and those without prominent lip canting. Conclusions: The findings of this study suggest that lip canting is strongly correlated with the mandibular symmetry plane, which includes menton deviation. This finding may have clinical implications with regard to the treatment of patients requiring correction of lip canting. Further studies are necessary for evaluating changes in lip canting after orthognathic surgery.

• 치과방사선
• /
• 제20권1호
• /
• pp.19-27
• /
• 1990

The primary objective of this study was to analyze the hard and soft tissue profile and comparison of the both sexes in Korean adults using roentgenocephalometry. The subjects were 122 males and 116 females from 18 to 22 years of age selected on the basis of their excellent occlusion and harmonious profile. It was an investigation about the interrelationships in the angles which consisted of Frankfort horizontal plane (FH plane), Sella Nasion plane (SN plane), Nasal floor plane (NF plane) and Mandibular plane (Md plane) as reference planes, and of the axial inclinations of the upper anterior tooth to Nasal floor plane (NF Plane) and of the lower anterior tooth to Mandibular plane (Md Plane). Among the 14 categories estabilishied on the soft tissue land marks, the 6 categories were studied for the relationship to Frankfort horizontal plane (FH Plane), and the 8 categories were studied for the soft tissue contour. The results were as follows: 1. Among 8 measured angles in the hard tissue, the angle of FH-Md, NF-Md and SN-Md were greater in females than in males. 2. The axial inclinations of the anterior teeth to NF Plane and Md plane were slightly greater in males than In females. 3. Among 14 measured angles in the soft tissue, the angles of G-Sn-P and E-Pog-Sn were greater in males, and FH-G-Sn, GㆍSn-Sn. Pog and Pog-Sn-P were greater in females. 4. In males, the variability of measured values in both lips region were high.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
• /
• 제43권3호
• /
• pp.152-159
• /
• 2017

Objectives: The aim of this study was to investigate the effects of advancement magnitude and changes in mandibular plane angle on the stability of mandibular advancement. Materials and Methods: This retrospective cohort study evaluated the postoperative stability of mandibular advancement in class II skeletal subjects who underwent bilateral sagittal split osteotomy. Radiographs taken preoperatively, immediately postoperatively and 1 year postoperatively were traced and analyzed using linear and angular measurements. To determine horizontal and vertical relapse, an X-Y coordinate system was established in which the X-axis was constructed by rotating S-N downward by $7^{\circ}$ (approximation of the Frankfort horizontal plane) and the Y-axis was defined as a line perpendicular to the X-axis and passing through the point Sella. For certain reference points including point A, point B, pogonion and menton, the perpendicular distance between each point and both axes was determined and cephalometric variables were recorded as X and Y coordinates. Results: Twenty-five subjects were studied. A significant correlation between the amount of mandibular advancement and relapse in the B point (vertical and horizontal) and the pogonion point was observed (vertical and horizontal, P<0.001). Evaluation of data demonstrated a positive correlation between the mandibular plane angle (SN/ML) change and vertical relapse in the B point (P<0.05). A simple regression model demonstrated that 74% of horizontal relapse and 42.3% of vertical relapse in the B point was related to the amount of mandibular advancement. The receiver operating characteristic test showed that 8.5 mm mandibular advancement is related to a relapse rate of 1 mm or more in the pogonion, vertically or horizontally. Conclusion: The magnitude of mandibular advancement is a stronger surgical predictor for horizontal rather than vertical relapse at the B point. Changes in mandibular plane angle (SN/ML) during surgery affect vertical, but not horizontal relapse at the B point.

• The Journal of Advanced Prosthodontics
• /
• 제5권1호
• /
• pp.58-66
• /
• 2013

PURPOSE. The purpose of this study was to decide the most appropriate point on tragus to be used as a reference point at time of marking ala tragus line while establishing occlusal plane. MATERIALS AND METHODS. The data was collected in two groups of subjects: 1) Dentulous 2) Edentulous group having sample size of 30 for each group with equal gender distribution (15 males, 15 females each). Downs analysis was used for base value. Lateral cephalographs were taken for all selected subjects. Three points were marked on tragus as Superior (S), Middle (M), and Inferior (I) and were joined with ala (A) of the nose to form ala-tragus lines. The angle formed by each line (SA plane, MA plane, IA plane) with Frankfort Horizontal (FH) plane was measured by using custom made device and modified protractor in all dentulous and edentulous subjects. Also, in dentulous subjects angle between Frankfort Horizontal plane and natural occlusal plane was measured. The measurements obtained were subjected to the following statistical tests; descriptive analysis, Student's unpaired t-test and Pearson's correlation coefficient. RESULTS. The results demonstrated, the mean angle COO (cant of occlusal plane) as $9.76^{\circ}$, inferior point on tragus had given the mean angular value of IFH [Angle between IA plane (plane formed by joining inferior point-I on tragus and ala of nose- A) and FH plane) as $10.40^{\circ}$ and $10.56^{\circ}$ in dentulous and edentulous subjects respectively which was the closest value to the angle COO and was comparable with the values of angle COO value in Downs analysis. Angulations of ala-tragus line marked from inferior point with occlusal plane in dentulous subject had given the smallest value $2.46^{\circ}$ which showed that this ala-tragus line was nearly parallel to occlusal plane. CONCLUSION. The inferior point marked on tragus is the most appropriate point for marking ala-tragus line.

• 제어로봇시스템학회논문지
• /
• 제21권11호
• /
• pp.1050-1056
• /
• 2015

In this paper, we use the characteristics of electromagnetic waves underwater attenuation for estimating linear distance between a transmitting node and receiving node, and research underwater vertical plane attenuation model for constructing the underwater localization system. The underwater localization of 2 dimensional with the plane attenuation model in the horizontal plane (H-plane) was proposed previous research. But for the 3 dimensional underwater localization, the additional vertical plane (E-plane) model should be considered. Because the horizontal plane of omnidirectional antenna has the same attenuation tendency in x-y plane according to the distance, whereas in vertical plane shows an irregular pattern in x-z plane. For that reason, in the vertical plane environment, the attenuation should be changed by the position and inclination. Hence, in this paper the distance and angle between transmitting and receiving node are defined using spherical coordinate system and derive an antenna gain pattern using half power beam width (HPBW). The HPBW is called a term which defines antenna's performance between isotropic and other antennas. This paper derives omnidirectional antenna's maximum gain and attenuation pattern model and define vertical plane's gain pattern model using HPBW. Finally, experimental verifications for the proposed underwater vertical plane's attenuation model was executed.

• Geomechanics and Engineering
• /
• 제30권1호
• /
• pp.67-73
• /
• 2022

In this study, the fiber orientation distribution (FOD) is investigated using both micro-CT (computerized tomography) and image analysis of physically cut specimens prepared from Polyvinyl Alcohol (PVA) fiber reinforced cemented Toyoura sand. The micro-CT images of the fiber reinforced cemented sand specimens were visualized in horizontal and vertical sections. Scans were obtained using a frame rate of two frames and an exposure time of 500 milliseconds. The number of images was set to optimize and typically resulted in approximately 3000 images. Then, the angles of the fibers for horizontal sections and in vertical section were calculated using the VGStudio MAX software. The number of fibers intersecting horizontal and vertical sections are counted using these images. A similar approach was used for physically cut specimens. The variation of results of fiber orientation between micro-CT scans and visual count were approximately 4-8%. The micro-CT scans were able to precisely investigate the fiber orientation distribution of fibers in these samples. The results show that 85-90% of the PVA fibers are oriented between ±30° of horizontal, and approximately 95% of fibers have an orientation that lies within ±45° of the horizontal plane. Finally, a comparison of experimental results with the generalized fiber orientation distribution function 𝜌(θ) is presented for isotropic and anisotropic distribution in fiber reinforced cemented Toyoura sand specimens. Experimentally, it can be seen that the average ratio of the number of fibers intersecting the finite area on a vertical plane to number of fibers intersecting the finite area on a horizontal plane (N^V_tot/N^H_tot) cut through a sample varies from 2.08 to 2.12 (an average ratio of 2.10 is obtained in this study). Based up on the analytical predictions, it can be seen that the average N^V_tot/N^H_tot ratio varies from 2.13 to 2.17 for varying n values (an average ratio of 2.15).

• Structural Engineering and Mechanics
• /
• 제62권5호
• /
• pp.643-649
• /
• 2017

Masonry walls are amongst the oldest building systems. A large portion of the research on these structures focuses on the load-bearing walls. Numerical methods have been generally used in modelling load-bearing walls during recent years. In this context, macro and micro modelling techniques emerge as widely accepted techniques. Micro modelling is used to investigate the local behaviour of load-bearing walls in detail whereas macro modelling is used to investigate the general behaviour of masonry buildings. The main objective of this study is to investigate the elastic behaviour of the load- bearing walls in masonry buildings by using micro modelling technique. In order to do this the brick and mortar units of the masonry walls are modelled by the combination of plane truss elements and plane frame elements with no shear deformations. The model used in this study has fewer unknowns then the models encountered in the references. In this study the vertical frame elements have equivalent elasticity modulus and moment of inertia which are calculated by the developed software. Under in-plane static loads the elastic displacements of the masonry walls, which are encountered in literature, are calculated by the developed software, where brick units are modelled by plane frame elements, horizontal joints are modelled by vertical frame elements and vertical joints are modelled by horizontal plane truss elements. The calculated results are compatible with those given in the references.

• 대한토목학회논문집
• /
• 제32권5A호
• /
• pp.267-275
• /
• 2012

본 연구에서는 철근 콘크리트 벽과 강판 콘크리트 벽이 이질접합 형태로 만나는 구조물의 휨 및 전단거동 특성을 검토하기 위하여 L형과 I형 타입의 실험체를 제작하고 구조실험을 수행하였다. 실험 시, 지진하중 등에 대한 실험체의 동적특성을 확인하기 위하여 Push 및 Pull을 반복하는 싸이클 하중을 구현하고자 하였다. L형 실험체에 대한 면외 휨 실험결과, 실험체의 공칭강도를 초과하는 휨 성능을 발휘하였으며, 이에 따라 설계에 적용된 수직철근의 미겹침 이음길이의 타당성을 확인할 수 있었다. 한편, 강판 콘크리트 벽 내에 수평철근의 배근 유무를 변수로 구성한 두 개의 I형 실험체에 대한 면내 전단 실험결과, 수평철근의 배근 유무에 상관없이 공칭강도를 초과하는 전단 성능을 보였다.

• 한국융합학회논문지
• /
• 제11권5호
• /
• pp.81-86
• /
• 2020

본 연구의 목적은 20대 여대생들을 대상으로 수평면에서 어깨각도의 변화에 따라 악력의 차이를 알아보았다. 여대생 20명을 대상으로 바로 선 상태에서 수평면에서 어깨각도 중립자세, 수평면에서 어깨각도 40도 수평모음자세, 수평면에서 어깨각도 40도 수평벌림자세에서 악력검사를 실시하였다. 실험통계는 자세각도에 따른 악력의 결과를 비교하기 위해 일요인 반복측정분석으로 실시하였다. 실험결과를 보면 어개각도의 중립자세에서 약력이 다른 두 자세보다 더 큰 증가하였다. 변화량 검증에서는 중립자세, 어깨각도 40도 수평모음자세 사이에서 유의한 차이를 보였다(p<.05). 수평면에서 어깨각도 중립상태에서 악력의 힘이 가장 큰 결과를 나타났으며 일상생활에서도 중립자세에서 활동을 할 때 효율적인 근력을 사용할 것으로 사료된다.