• The korean journal of orthodontics
• /
• v.29 no.3 s.74
• /
• pp.303-315
• /
• 1999

The aim of this study was to evaluate the morphology of the mandibular symphysis and anterior alveolar and skeletal relationship under the influence of the rotational growth pattern of mandible in skeletal Class III malocclusion. A total of U untreated adult subjects were divided into two groups-forward rotational growth pattern group, backward rotational growth pattern group-according to the suggestion of Skieller et al.. The antero-posterior position, vertical relationship, mandibular symphysis and anterior alveolar and skeletal relationship were assessed on lateral cephalometric radiographs. Mandibular symphysis and anterior alveolar and skeletal relationship in each subject were studied and the following conclusions were drawn : 1. Concerning the antero-posterior position, forward rotational growth pattern group showed significantly larger SNA, SNB. Conceming the vertical relationship, all measurements showed statistically significant differences. 2. Forward rotatioal growth pattern group showed significantly larger IMPA, MnAD, backward rotational growth pattern group showed significantly larger MxABH. 3. There was no statistically significant difference in symphysis ratio to mandibular plane between forward and backward rotational growth pattern group. 4. In the correlative analysis of rotational growth pattern of mandible and mandibular symphysis, anterior alveolar and skeletal relationship, statistically significant correlations in overbite, IMPA, MnAD, symphysis width were showed.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.7 no.4
• /
• pp.536-547
• /
• 1997

For various angular velocities of crucible and crystal, the characteristics of melt flows, temperatures and concentrations of oxygen are numerically studied in the Czochralski furnace with a uniform axial magnetic field. Buoyancy effect due to the heating of crucible wall and thermocapillary effect due to the temperature gradient at the free surface, can be differentiably suppressed by the centrifugal forces due to the rotations of the crucible and crystal. The most important factor which yields the centrifugal forces is the rotation velocity of the crucible, that influences the fields of velocities, temperatures and concentrations. In the case that the crucible rotation velocity is not high, the rotations of the crystal gives rise to the centrifugal forces effectively.

• Journal of the Korean Society of Mechanical Technology
• /
• v.13 no.3
• /
• pp.99-106
• /
• 2011

50kW급 동체회전형 파력발전시스템(WEC;wave energy converter)의 전력변환장치(PTO; power take-off)를 설계 제작한 후 성능시험을 하였다. 파력발전시스템은 2개의 실린더형 동체가 회전관절로 연결된 구조로 수면의 반정도 잠기는 구조로 되어있다. 파랑에 의해 유도된 회전관전의 움직임이 유압실린더에 힘을 가해주며, 유압실린더는 고압의 작동유를 축압기를 경유하여 발전기에 체결된 유압모터로 공급한다. 유압식 PTO은 유압실린더가 왕복운동하는 움직임을 이용하여 고품질의 전력을 생산하는데 효과전인 수단을 제공한다. 파력발전시스템의 경제성은 PTO의 에너지 변환 효율에 크게 의존한다. 발전기를 AC 380V 전력계통에 연계시킨 후, 발전기에서 나오는 출력이 5, 20, 35, 43kW 일때 PTO 전체와 개별기기에 대한 효율을 측정하였다. 본 논문에서 유압식 PTO시스템의 설계에 대해 설명하였으며 효율 향상에 초점을 맞추어 PTO 성능대해 분석하였다.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.4 no.2
• /
• pp.111-118
• /
• 1994

Silicon single crystals were continuously grown by a modified process. Polycrystalline silicon powder was fed from the top reservoir to the growth chamber. Silicon single crystals were grown from the botton of the growth chamber. The balance between the gravitational force of melt and the centrifugal force originated from the rotation of seed was the one of the main factors to control the diameter of crystals grown and quality, etc.

• Korean Journal of Cleft Lip And Palate
• /
• v.5 no.2
• /
• pp.117-122
• /
• 2002

성장기 환자에서의 각 부위별 임플란트 식려 시기를 요약해보면 다음과 같다. 1) 상악전방부 : 외상이나 선천적 결손을 해결하는 방법으로 임플란트를 사용하는 술식이 권장하지만 성장이 완료되지 않았기 때문에 야기되는 문제를 해결하기 위해 성장이 완료될 때까지 연기하는 것이 좋다. 2)상악 후방부: 수직적인 성장량이 최고 1cm까지 일어날 수 있으면 상악동의 흡수로 조기에 임플란트 침강과 치근부의 노출을 야기할 수 있다. 그리고 동시에 보철에 의한 구개열의 횡적인 성장방해를 피해야한다. 3) 하악 전방부 : 무치증 아이에서 임플란트의 조기식립이 적응증이 되는 유일한 곳으로 치아가 없을 때는 치조골의 성장이 최소이며 초기에 횡적, 후방 성장이 대부분 완료된다. 그러나 단일 임플란트 식립은 권장되지 않는다. 4)하악후방부: 늦게까지 성장변화가 지속되기 때문에 전후방, 횡적, 수직적 성장의 많은 양이 일어난다. 하악의 회전성장의 영향을 많이 받아 하악 무치악에서 조기 임플란트 사용한 보고도 적고. 자연치아에 인접하여 임플란트를 식립한 기록은 있으나 골격성장이 완료될 때 까지는 식립하지 않는 것이 좋다.

• Journal of Korea Society of Industrial Information Systems
• /
• v.24 no.3
• /
• pp.1-21
• /
• 2019

The objective of this study is three-fold: to investigate the relationship between information technology (IT) investment and inventory turnover, using 98 U.S. firms spanning eleven years (from 1999 to 2009); to analyze the correlation of inventory turnover with firm and industry characteristics, where vertical integration and growth options are chosen to reflect the features of the firm's internal characteristics, and industry dynamism and industry concentration are selected to represent the industry's competitive environment; and to examine time trends in inventory turnover. The significant findings include the following: (i) both IT investment and growth options have a positive impact on inventory turnover; (ii), but vertical integration and industry concentration have a negative impact on inventory turnover; (iii) the impact of industry dynamism on inventory turnover positive; and (iv) the time trends in inventory turnover and 'adjusted inventory turnover' have been increased during the sample period from 1999 to 2009.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.326-326
• /
• 2013

본 연구에서는 회전 원통형 마그네트론 스퍼터링 시스템(Cylindrical Magnetron Sputtering)을 이용하여 성막한 Sn-doped $In_2O_3$ (ITO) 투명전극의 두께 변화에 따른 전기적, 광학적, 구조적 특성을 연구하였다. 회전 원통형 마그네트론 스퍼터링 시스템을 이용한 ITO 투명전극은 박막의 두께가 50~1,000 nm의 두께로 증가함에 따라 비저항 값은 일정하게 유지되나 면저항 값이 $37.8{\Omega}$/square로부터 $1.5{\Omega}$/square로 점차적으로 감소됨을 확인할 수 있었다. 또한 ITO 박막의 두께 증가가 50 nm에서 1,000 nm로 증가함에 따라 400~800nm 파장 범위에서 71~83％의 높은 광투과도를 나타내었다. 두께 변화에 따른 광학적 특성 변화를 설명하기 위해 Spectroscopic ellipsometry 분석을 실시하였으며 이를 기반으로 박막 두께와 투과도의 상관관계를 설명하였다. 한편, 원통형 마그네트론 스퍼터로 성장시킨 ITO 박막은 두께가 50~200 nm의 범위에서는 (222) 방향으로 우월 성장하였으나, 200-1000 nm 두께 범위에서는 우월 성장방향이 (400)과 (622)로 바뀜을 X-ray diffraction (XRD) 분석을 통하여 확인하였다. 이를 통해 박막의 두께변화에 따른 전기적/광학적 특성의 변화는 박막의 구조와 매우 밀접한 상관관계가 있음을 알 수 있었다.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.3 no.2
• /
• pp.117-124
• /
• 1993

It was found that the basic principle of continuous crystal growth method was following as; the powder supplied from the feeding system is molten in the graphite crucible under the ambient gas. After forming the molten zone in the lower part of the crucible, the seed crystal is deeped into the melt and pulled down with the rotation so that the melt crystallized from the seed. When the lowering rate, rotation rate, feeding rate and temperature are correct, the single crystal can grow. The critical melt level, the feeding rate, the growth rate, the change of the shape of molten zone by the graphite susceptor and crucible, the position of work coil, the balance between the gravitational force of melt and the centrifugal force originated from the rotation of seed which are the variables of the crystal growth and the sintering phenomenon of melt surface were researched.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2007.11a
• /
• pp.13.1-13.1
• /
• 2007

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.8 no.1
• /
• pp.18-28
• /
• 1998

A laboratory experiment was made of a control of temperature oscillation in Czochralski convection. Numerical computation was also made to delineate the control of temperature oscillation. The suppression of temperature oscillation was achieved by varying the rotation rate of crystal rod ($\Omega=\Omega_0(1+A sin 2{\pi}ft/t_p)$), where A denotes the amplitude of rotation rate and f the frequency factor. Based on the inherent dimesionless time period of temperature oscillation ($t_p$), the suppression rate of temperature oscillation was characterized by the mixed convection parameter ($0.217{\leq}Ra/PrRe^2{\leq}1.658$). The optimal values of A and f were also scrutinized. To understand the suppression mechanism of temperature oscillation, the controls of isotherm($\theta$) and equi-vorticity($\omega$) were investigated.