• 대한수학회보
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• 제33권4호
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• pp.613-618
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• 1996

In this paper, M will always denote an n- dimensional complete Riemannian manifold and $\omega_n$ is the volume of $S^n$.

• 패션비즈니스
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• 제12권2호
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• pp.1-11
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• 2008

The purpose of this study is to explore to determine the maximum volume with doing permanent waving in flat crown of the head. The method was like this. First of all, the diameter, the ratio of the circumference of a circle to its diameter and the number of rotations were analyzed same hair using permanent waving rods each number of 1$\sim$10. Secondly, the increasing rate of volume of curls number of 1$\sim$10 was analyzed. According to the result of the experiment, as the number of permanent waving rods were bigger, the ratio of the circumference of a circle to its diameter constant was increasing but the number of rotations was decreased. When the permanent waving rods of each number 1-3(Big diameter) were used, the volume was decreased. That's because there was fewer rotation compared to the diameter and was no ample combed dried hair. Due to this kind of reason, there was no perfect curling. Once number 10 permanent waving rods (most small size) was used, the shape of curling was strong and the stability was made after combed dried hair. But volume was decreased by 9% because of the cohesive power. In case of number of 4$\sim$9 rods used, volume was increased. Volume was highest when permanent waving rods was number 5 which was used combing on base both morphology and numerical value.

• Radiation Oncology Journal
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• 제30권2호
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• pp.70-77
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• 2012

Purpose: To evaluate the patterns of tumor shape and to compare tumor volume derived from simple diameter-based ellipsoid measurement with that derived from tracing the entire tumor contour using region of interest (ROI)-based 3D volumetry with respect to the prediction outcome in cervical cancer patients treated with concurrent chemotherapy and radiotherapy. Materials and Methods: Magnetic resonance imaging was performed in 98 patients with cervical cancer (stage IB-IIIB). The tumor shape was classified into two categories: ellipsoid and non-ellipsoid shape. ROI-based volumetry was derived from each magnetic resonance slice on the work station. For the diameter-based surrogate "ellipsoid volume," the three orthogonal diameters were measured to calculate volume as an ellipsoid. Results: The more than half of tumor (55.1%) had a non-ellipsoid configuration. The predictions for outcome were consistent between two volume groups, with overall survival of 93.6% and 87.7% for small tumor (<20 mL), 62.9% and 69.1% for intermediate-size tumor (20-39 mL), and 14.5% and 16.7% for large tumors (${\geq}$40 mL) using ROI and diameter based measurement, respectively. Disease-free survival was 93.8% and 90.6% for small tumor, 54.3% and 62.7% for intermediate-size tumor, and 13.7% and 10.3% for large tumor using ROI and diameter based method, respectively. Differences in outcome between size groups were statistically significant, and the differences in outcome predicted by the tumor volume by two different methods. Conclusion: Our data suggested that large numbers of cervical cancers are not ellipsoid. However, simple diameter-based tumor volume measurement appears to be useful in comparison with ROI-based volumetry for predicting outcome in cervical cancer patients.

• 한국분무공학회지
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• 제15권1호
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• pp.8-16
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• 2010

This paper present the diesel spray characteristics at different injection system parameters in a HSDI diesel engine. The spray characteristics was calculated by the coupled simulation of fuel injection system model and three-dimensional KIVA-3V code with TAB spray model. The relevant injection parameters are accumulator volume, control chamber initial volume, control orifice diameter, needle valve diameter and nozzle chamber initial volume, etc. Parametric investigation with respect to twelve relevant injection parameters showed that there was a significant advantage in varying control chamber initial volume, control chamber orifice diameter, and nozzle chamber orifice diameter with respect to effect the SMD and fuel injection speed. Consequently, in order to design the fuel injection system for spray characteristics, it seems reasonable to suppose to be optimized the fuel injection system.

• 한국산림과학회지
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• 제96권3호
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• pp.362-368
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• 2007

본 연구는 잣나무와 낙엽송을 대상으로 흉고직경급에 따른 임목의 용도별 이용재적 및 목재수율을 산출하기 위해 수행되었다. 먼저 기존에 개발된 수간곡선, 수고 추정식을 이용하여 입목의 형상에 따른 수간 재적량을 산출하였다. 그리고 일반용재와 펄프재의 이용재적 및 조재수율, 일반용재를 판재 및 각재로 가공했을 때 제재목의 이용재적 및 조재수율을 직경급별로 산출하였다. 연구결과에 따르면 수간재적에 있어서 낙엽송의 재적이 잣나무보다 동일한 흉고직경급에 있어서 23~38% 높게 나타났다. 일반용재 생산은 2개 수종 모두 흉고 직경급 18 cm부터 가능하였다. 또한 일반용재와 펄프재용 원목의 조재수율 합계는 흉고직경이 커지는 초기에 급격하게 증가하였고 잣나무의 경우 흉고직경 26 cm에서 90%, 낙엽송의 경우 흉고직경 38 cm에서 88%로 최대로 나타났다. 한편 판재의 조재수율은 23~56%, 각재는 그 생산크기가 커질수록 조재수율이 떨어지는 것으로 나타났다. 이 연구의 결과는 산림의 이용재적 산출 및 임목평가 그리고 제재목의 결정에 활용될 수 있을 것이다.

• 한국정밀공학회지
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• 제22권3호
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• pp.86-92
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• 2005

In this paper a forward-backward can extrusion process are analyzed by using rigid-plastic FEM simulation. FEM simulation is conducted to investigate forming characteristics such as deformation modes fur different process parameters. Design parameters such as thickness ratio, punch angle, friction factor and diameter ratio are selected to study the effect of them on the pattern of material flow. The analysis is focused mainly on the influences of the design factors on deformation pattern in terms of forming load, extruded length ratio and volume ratio. It is known for the simulation that the forming load, the length ratio and the volume ratio increase as the thickness ratio (TR), the wall thickness in forward direction to that in backward direction, decreases. The various punch angles have slight influence on the forming load. length ratio and volume ratio. However friction factor have little effect on the forming characteristics such as the forming load, volume ratio and so on. In addition the forming load increases as diameter ratio (DR), the outer diameter of a can in forward direction to that in backward direction, increases. Furthermore the extruded length ratio is lowest with a certain value of DR=0.85 among diameter ratios. Pressure distribution exerted on the die-material interface is illustrated schematically.

• 한국환경보건학회지
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• 제32권2호
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• pp.179-185
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• 2006

Effect of organic loading rate on UASB performance was evaluated under the renditions of some surface area/reactor volume ratio and different reactor diameter. At the low leading rate of 0.4 kg $COD/m^3{\cdot}d$, reactor performance was not affected by reactor diameter. At the organic loading rate of 6 kg $COD/m^3{\cdot}d$, however, volatile acid accumulation and low COD removal efficiency is observed in reactor having 6.4 cm diameter, while volatile acid is not accumulated at all and high COD removal efficiency is observed in reactor having 3 cm diameter. Such a difference of reactor performance depending on reactor diameter can be explained that sludge bed can be fluidized by evolved gas bubble in narrow reactor, while sludge bed ran not be fluidized by evolved gas bubble only in wide reactor. At a high organic loading rate of 20 kg $COD/m^3{\cdot}d$, it can be judged that there is no relation between reactor configuration and reactor performance because all reactors showed very low COD removal efficiencies regardless of reactor diameter. Narrow and tall type reactor is favorable condition for making sludge bed fluidization at a constant surface area/reactor volume ratio. Thus, it can be judged that reactor configuration and sludge bed fluidization have great influence to reactor performance.

• 한국입자에어로졸학회지
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• 제8권2호
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• pp.89-95
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• 2012

Spherical mesoporous silica particles, of which main pore diameter was 3.8 nm, were successfully prepared by spray pyrolysis from aqueous silicic acid. The effect of precursor concentration, reaction temperature, and the addition of urea and PEG on the particle diameter and pore properties such as pore diameter, total pore volume, and specific surface area were investigated by using FE-SEM, particle size analyzer, and nitrogen absorption-desorption analysis. With an increase of the precursor concentration from 0.2 M to 0.7 M, the average particle diameter, total pore volume, and specific surface area of the porous silica particles increased from 0.56 to $0.96\;{\mu}m$, 0.434 to $0.486\;cm^3/g$, 467.8 to $610.4\;m^2/g$, respectively. Within the temperature range $(600\;^{\circ}C{\sim}800\;^{\circ}C)$, there was no significant difference in the pore diameter, total pore volume, and specific surface area. In addition, the addition of urea as an expansion aid led to slight increases in particle diameter, pore diameter, and specific surface area. However, when the polyethylene glycol (PEG) as an organic template was used, the total pore volume of porous particles increased dramatically.

• Maxillofacial Plastic and Reconstructive Surgery
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• 제38권
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• pp.23.1-23.7
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• 2016

Background: The purpose of this retrospective study was to develop a two- and three-dimensional analysis of the airway using cone-beam computed tomography (CBCT) and to determine whether the airway space would be changed in mandibular prognathism after bimaxillary surgery involving maxillary posterior impaction. Methods: Patients requiring orthognathic surgery from 2012 to 2014 were recruited for this study. CBCT scans were obtained at three points: preoperatively (T0), immediate postoperatively (T1), and after 6 months postoperatively (T2). The nasopharynx, oropharynx, and hypopharynx were measured on the CBCT scan for each patient in a repeatable manner. With the midsagittal plane, linear measurements in the middle of each were obtained. For the CBCT, volumetric measurements of each and total airway were obtained. Results: A total of 22 consecutive patients (11 men and 11 women) were included in the present study. The total volume was significantly reduced (p < .001). However, the change of the diameter and volume of the nasopharynx was not statistically significant (p = .160, p = .137, respectively). In the oropharynx, the change of both the diameter and volume showed statistical significance between preoperatively and immediate postoperatively (p < .001, p = .001, respectively) and also preoperatively and after 6 months postoperatively (p = .001, p = .010, respectively). In the hypopharynx, the change of both the diameter and volume showed statistical significance between preoperatively and immediate postoperatively (p = .001, p < .001, respectively) and also preoperatively and after 6 months postoperatively (p = .001, p < .001, respectively). Conclusions: The bimaxillary surgery involving maxillary posterior impaction can reduce the volume of airway in the patients of mandibular prognathism. Although total airway volume was reduced significantly, the changes in the volume and diameter of the nasopharynx were not statistically significant. The maxillary posterior impaction affects on the nasopharyngeal airway minimally.

• 한국산림과학회지
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• 제18권1호
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• pp.9-12
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• 1973

1. 본(本) 조사(調査) 16년생(年生)의 리기다소나무임분(林分)에 대(對)한 재적생장량(材積生長量)과 장래(將來)의 임분재적예측(林分材積豫測) 임분표법(林分表法)에 의하여 추정(推定)한 것이다. 2. 직경성장량(直徑成長量) 조사(調査)는 'Meyer'의 Increment borer법(法)에 의하고 단목재적(單木材積)은 기(旣) 조사(調査)된 V=0.000058 $D^{1.8}{\times}{\cdot}H^{1.1}$의 재적식(材積式)에 의하여 각각(各各) 조사(調査)되었다. 3. 0.33ha의 표준지(標準地)를 설정(設定)하고 표준지내(標準地內) 339본(本)의 임목(林木)에 대(對)하여 95%의 신뢰도(信賴度)로서 조사(調査)한 결과(結果)는 다음과 같다. 1) 직경(直徑)에 대(對)한 직경연년성장량(直徑連年成長量)의 회귀식(回歸式)은 Y=0.1618 +0.0298x. 이다. 2) 2cm 괄약(括約)의 직경분포(直徑分布)에서 전임목(全林木) 본수(本數)의 약(約) 90%가 완전(完全) 1계급(階級) 진급(進級)을 하였다. 3) 임분재적성장율(林分材積成長率)은 16%의 고도(高度)의 성장율(成長率)을 나타냈다. 4) 5개년간(個年間)의 재적성장량(材積成長量)은 46%의 증가율(增加率) 보이고있다.