• 한국식품과학회지
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• 제38권3호
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• pp.361-368
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• 2006

압출조건 즉, screw speed, screw configuration, 압출온도 및 원료투입량 등을 고정하고, 가수량을 조절하여 압출미삼을 제조하여 냉수 및 열수에서의 추출율, 총당, 우론산 및 비전분 탄수화물의 함량과 당 조성을 분석하였다. 가수량이 감소될수록 압출온도와 SME는 증가하고, 고형분, 총당 및 우론산의 추출율도 증가하였다. 추출율 증가는 열수추출에서 보다 상온추출에서 크게 증가하였다. 최적조건인 압출온도 $155^{\circ}C$에서 처리한 미삼 분말의 비전분 탄수화물의 추출율이 증가하였고, 추출된 NSP의 분자량은 냉수추출에서는 압출처리 미삼이 열수추출에서는 대조구에서 큰 분자량이 추출되었다. NSP의 당 조성은 미삼의 비전분 다당체의 주된 구성당은 arabinose와 galactose였고, 상온에서 추출된 압출 미삼의 경우 높은 함량의 glucose가 측정되었으며, 열수에서 추출된 미삼의 비전분 다당체는 대조구와 압출미삼 모두에서 glucose 및 xylose가 측정되었다. 이상의 결과로 구연산이 첨가된 미삼과 첨가되지 않은 미삼을 이용하여 $155^{\circ}C$에서 압출성형 하는 것이 최적조건임을 확인하였다. 최적조건에서 압출성형 된 압출미삼의 냉수추출의 경우 사포닌 추추율은 대조구에 비해 약 2배가량 높게 나타났다. 또한 압출처리에 의해 사포닌의 구성 성분 중 Rg3가 생성되었다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제43권2호
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• pp.77-82
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• 2017

Objectives: The aim of this study was to compare the mechanical resistance of four different osteosyntheses modeled in two different sagittal split ramus osteotomy (SSRO) designs and to determine the linear loading in a universal testing machine. Materials and Methods: An in vitro experiment was conducted with 40 polyurethane hemimandibles. The samples were divided into two groups based on osteotomy design; Group I, right angles between osteotomies and Group II, no right angles between osteotomies. In each group, the hemimandibles were distributed into four subgroups according to the osteosynthesis method, using one 4-hole 2.0 mm conventional or locking plate, with or without one bicortical screw with a length of 12.0 mm (hybrid technique). Each subgroup contained five samples and was subjected to a linear loading test in a universal testing machine. Results: The peak load and peak displacement were compared for statistical significance using PASW Statistics 18.0 (IBM Co., USA). In general, there was no difference between the peak load and peak displacement related to osteotomy design. However, when the subgroups were compared, the osteotomy without right angles offered higher mechanical resistance when one conventional or locking 2.0 mm plate was used. One locking plate with one bicortical screw showed higher mechanical resistance ($162.72{\pm}42.55N$), and these results were statistically significantly compared to one conventional plate with monocortical screws (P=0.016) and one locking plate with monocortical screws (P=0.012). The difference in peak displacement was not statistically significant based on osteotomy design or internal fixation system configuration. Conclusion: The placement of one bicortical screw in the distal region promoted better stabilization of SSRO. The osteotomy design did not influence the mechanical behavior of SSRO when the hybrid technique was applied.

• 한국항해학회지
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• 제25권4호
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• pp.443-453
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• 2001

선박조종시뮬레이터는 해기사의 교육 훈련, 항만 수로 설계 시 안전성 평가, 선박설계시 조종성능의 검토등으로 널리 활용되고 있다. 본 논문은 최근 한국해양대학교에서 개발한 선박조종시뮬레이터를 소개하고 개발 과정과 활용에 대하여 논의한다. 본 시뮬레이터는 Operation Panel, Instructor's Console, Ship Dynamics Calculation, 3D Bridge View, 2D Bird's Eye View 및 Navigational Indicators의 6구성요소로 이루어져 있으며, 이를 위해 8대의 퍼스널 컴퓨터가 배치되어 있다. 모든 구성요소들은 효율적인 정보 교환을 위하여 분산처리네트워크 방식으로 연결되어 있다. 또한, 본 논문은 항만내에서의 저속 시 조종운동 수학모델과 가상현실 모델링에 대해서도 논의한다. 마지막으로, 부산항에 대한 2축2타선박의 접안 조종 시뮬레이션 예를 보여주고 있다.

• 한국생산제조학회지
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• 제23권2호
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• pp.164-172
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• 2014

This paper presents a method for analyzing the stiffness of full and low DOF (degree of freedom) planar parallel manipulators with serially connected legs. The individual stiffness of each leg is obtained by applying reciprocal screws to the leg twist using passive joints and elastic elements consisting of actuators and links. Because the legs are connected in parallel, the manipulator stiffness is determined by summing the individual leg stiffness values. This method does not require the assumption that springs should be located along reciprocal screws and is applicable to a planar parallel manipulator with a generic or singular configuration. The stiffness values of three planar parallel manipulators with different DOFs are analyzed. The numerical results are confirmed using ADAMS S/W.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 춘계 학술대회논문집
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• pp.1-13
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• 2005

Fluid flows within microchannels are characterized by low Reynolds numbers. Therefore the effect of mixing is a crucial factor in design of the channels. Since the action of the electro-osmotic or magnetic forces used in the mixing enhancement is usually periodic in the three-dimensional channel configuration, use of the various concepts of chaotic advection is reasonable in the quantification of the stirring effect. In this paper, the details of the method of material-stretching mapping is explained. The actual application of the method to the screw extruder is also presented.

• 대한족부족관절학회지
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• 제13권2호
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• pp.179-183
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• 2009

The triplane fracture has been described as a fracture of the distal tibial epiphysis occurring across three planes-sagittal, transverse and coronal. The characteristic pattern of fusion of distal tibial epiphysis explains the special configuration of the fragments in the triplane fracture. According to Dias-Tachdjian classification, triplane fracture is classified two part fracture, three part fracture, four part fracture and two part fracture with extension to the medial malleolus. Among four types, two part triplane fracture with extension to the medial malleolus is a relatively rare injury and generally is not treated by closed reduction. Such fractures should have an anatomic reduction and adequate fixation to restore the joint congruity and obtain an anatomic reduction of the growth plate to prevent a future growth deformity. This is usually best accomplished with an open reduction and screw fixation or k-wire fixation. We experienced two part triplane fracture with extension to medial malleolus and check the CT to define the extent of the injury completely. And then we underwent open reduction and screw fixation for the fracture. As a result, we present four cases of two part triplane fracture with extension with review of related literatures.

• 대한기계학회논문집
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• 제19권4호
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• pp.1023-1032
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• 1995

The multiple cooperating robot system plays an important role in the research of modern manufacturing system as the emphasis of production automation is more on the side of flexibility than before. While the kinematic and dynamic analysis of a single robot is performed as an open-loop chain, the dynamic formulation of robot in a multiple cooperating robot system differs from that of a single robot when the multiple cooperating robots form a closed kinematic chain holding an object simultaneously. The object may be any type from a rigid body to a multi-joint linkage. The mobility of the system depends on the kinematic configuration of the closed kinematic chain formed by robots and object, which also decides the number of independent input parameters. Since the mobility is not the same as the number of robot joints, proper constraint condition is sought. The constraints may be such that : the number of active robot joints is kept the same as mobility, all robot joints are active and have interrelations between each joint forces/torques, two robots have master-slave relation, or so on. The dynamic formulation of system is obtained. The formulation is based on recursive dual-number screw-calculus Newton-Eulerian approach which has been used for single robot analysis. This new scheme is recursive and compact symbolically and may facilitate the consideration of the object in real time.

• 한국기계가공학회지
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• 제15권6호
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• pp.35-40
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• 2016

In this study, the thermal and fluid dynamic characteristics for the coating process of large-sized water pipes was studied by heating the inside of a pipe directly with a gas burner. Heat and flow analyses were performed on large pipes with various inlet shapes. Using large pipes for coating was shown to be the proper shape for heating large pipes uniformly. This type has a screw with a diameter of 200 mm installed at the inlet to provide a rotational motion to the heating air. The rotational motion resulted in a uniform temperature distribution that ranged from $289.1^{\circ}C$ to $352.1^{\circ}C$ The optimized geometric configuration of the inlet of the pipe successfully and uniformly enhanced the thermal characteristics of the devised temperature limit.

• Structural Engineering and Mechanics
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• 제67권3호
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• pp.277-281
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• 2018

The analytical solution of two functionally graded layers with Volterra type screw dislocation is investigated under anti-plane shear impact loading. The energy dissipation of FGM layers is modeled by viscous damping and the properties of the materials are assumed to change exponentially along the thickness of the layers. In this study, the rate of gradual change ofshear moduli, mass density and damping constant are assumed to be same. At first, the stress fields in the interface of the FGM layers are derived by using a single dislocation. Then, by determining a distributed dislocation density on the crack surface and by using the Fourier and Laplace integral transforms, the problem are reduce to a system ofsingular integral equations with simple Cauchy kernel. The dynamic stress intensity factors are determined by numerical Laplace inversion and the distributed dislocation technique. Finally, various examples are provided to investigate the effects of the geometrical parameters, material properties, viscous damping and cracks configuration on the dynamic fracture behavior of the interacting cracks.

• 구강회복응용과학지
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• 제21권2호
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• pp.153-167
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• 2005

The purpose of this study was to compare the v-shape thread with the square shape thread of fixture in the view of stress distribution pattern using finite element stress analysis. The finite element model was designed with the parallel placement of two standard fixtures(4.0 mm diameter ${\times}$ 11.5 mm length) on the region of mandibular 1st and 2nd molars. Three dimensional finite element model was created with the components of the implant and surrounding bone. This study simulated loads of 200 N at the central fossa in a axial direction (load A), 200 N at the buccal offset load that is 2 mm apart from central fossa in a axial direction (load B), 200 N at the buccal offset load that was 4 mm apart from central fossa in a axial direction (load C). These forces of load A',B',C' were applied to a $15^{\circ}$ inward oblique direction at that same site with 200 N. Von Mises stress values were recorded and compared in the supporting bone, fixture, and abutment screw. The following results have been made based on this study : 1. The highest stress concentration occurred at the cervical region of the implant fixture. 2. Von Mises stress value of off-site region was higher than that of central fossa region. 3. Square shape thread type showed more even stress distribution in the vertical and oblique force than V-shape thread type. 4. Stress distribution was the most effective in the case of buccal offset load (2, 4 mm distance from central fossa) in the square shape thread type. 5. V-shape thread type revealed higher von Mises stress value than square shape thread type in all environmental condition. The results from numerical analyses concluded that square shape thread type had the lower destructive stress and more stress distribution between the fixture and bone interface than V-shape thread type. Therefore, square shape thread type was regarded as optimal thread configuration in biomechanical concepts.