• 한국해양공학회:학술대회논문집
• /
• 한국해양공학회 2000년도 춘계학술대회 논문집
• /
• pp.189-194
• /
• 2000

Due to the rapid growth of ship building industry and increment of ship construction in Korea, several hundred thousand of lifting lugs per year, have been installed at the lifting positions of ship block and removed after finishing their function, therefore, appropriate design system for strength check or optimal design of each lug structure has been required in order to increase the capability of efficient design. In this study, design system of D-type lifting lug structure which is most popular and useful in shipyards, was developed for the purpose of initial design of lug structure. Developed system layout and graphic user interface for this design system based on the C++ language were explained step by step. Using this design system, more efficient performance of lug structural design will be expected on the windows of personal computer.

• 대한치과보철학회지
• /
• 제43권2호
• /
• pp.258-263
• /
• 2005

Statement of problem. Implant screw loosening has been remained a problem in implant prosthodontics. The time needed to insert screw driver into abutment screw head should be shortened for the purpose of decreasing the chair time. Purpose. The purpose of this study was to investigate the effects of the design of abutment screw driver on the amount of time for insertion of screw driver into abutment screw head. Material and methods. Hexagonal and rectangular types of abutment screw drivers were used. The original abutment screw drivers were modified by grinding acute angle of the screw driver tip (modified drivers). Group 1 : hexagonal type abutment screw and original driver Group 2 : hexagonal type abutment screw and modified driver Group 3 : rectangular type abutment screw and original driver Group 4 : rectangular type abutment screw and modified driver UCLA lab analogues were located in acrylic resin block. The angulations of them were 0 and 20 degrees. The times needed for insertion were measured. Group 1 and 3 were used as controls. Results. 1. Group 2 showed shorter insertion time than group 1, regardless of implant angulations (p<.05). 2. Group 4 showed shorter insertion time than group 3, regardless of implant angulations (p<.05). Conclusion. Modified abutment screw drivers required less amount of time to insert screw driver into abutment screw head. Modification of abutment screw driver was beneficial.

• 대한조선학회논문집
• /
• 제51권1호
• /
• pp.42-50
• /
• 2014

Lifting lugs are frequently used in shipyard to transportate and turn over blocks. As the shipbuilding technology develops, blocks has become bigger and bigger, and block management technology takes a more important role in shipbuilding to enhance the productivity. For the sake of economic as well as safe design of lug structure, more rigorous analysis is needed. In this study in order to investigate the strength characteristics of two type of lug, that is, D and T type lugs, non-linear strength analysis has been carried out to compare the ultimate strength characteristics of two types of lug varying in-plane and out-of-plane loading directions. Based on the present numerical analysis results, it can be drawn that T type lug is superior to D type lug from view points of ultimate strength and deformation.

• 한국전산유체공학회지
• /
• 제14권2호
• /
• pp.59-67
• /
• 2009

An accurate prediction of the bypass flow is of great importance in the VHTR core design concerning the fuel thermal margin. Nevertheless, there has not been much effort in evaluating the amount and the distribution of the core bypass flow. In order to evaluate the behavior and the distribution of the coolant flow, a unit-cell experiment was carried out. Unit-cell is the regular triangular section which is formed by connecting the centers of three hexagonal blocks. Various conditions such as the inlet mass flow rate, block combinations and the size of bypass gap were examined in the experiment. CFD analysis was carried out to analyze detailed characteristics of the flow distribution. Commercial CFD code FLUENT 6.3 was validated by comparing with the experimental results. In addition, SST model and standard k-$\varepsilon$ model were validated. The results of CFD simulation show good agreements with the experimental results. SST model shows better agreement than standard k-$\varepsilon$ model. Results showed that block combinations and the size of the bypass gap have an influence on the bypass flow ratio but the inlet mass flow rate does not.

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
• /
• 제53권12호
• /
• pp.718-724
• /
• 2004

This study investigates the design factors of Interior Permanent Magnet Synchronous Motor(IPMSM) which is applied to Hybrid electric vehicle as a driving power. Recently, there are many studies of IPMSM for application to Hybrid Electric Vehicle, because IPMSM has characteristics of high torque, high power density and high efficiency which come from reluctance torque due to difference of inductance as well as magnet torque. This study analyzes the inductance and design characteristics of IPMSM by using finite element method and focuses on design and analysis of IPMSM which can operates with high efficiency at low speed range. For this embodiment, magnet shape is changed from conventional block type to arc type without any change of outline dimension of motor and this change of magnet shape makes it possible to increase back EMF and sinusoidal waveform. Analysis results are verified by test of improved and embodied motor. As a test result , increased back EMF and sharply decrease of harmonics are secured and through this contribution of reduced fuel consumption of Hybrid electric vehicle is expected.

• 패션비즈니스
• /
• 제26권5호
• /
• pp.135-152
• /
• 2022

This study aimed to evaluate the user experience of hearable devices for seniors and suggest possible development directions. A literature review, case study, and in-depth interviews were conducted. Based on the literature review, convenience, accessibility, transmissibility, wearability, aesthetics, and interest were determined as the user experience factors of hearable devices. Then, in-depth interviews were conducted with 12 participants aged 60 or older regarding four devices. Participants tried four different types of wireless earphones which were selected based on a case study: open-type, kernel-type, neckband-type, and earring-type. Regarding convenience, the participants preferred to carry small devices and regarding accessibility, participants responded positively for most product types. For transmissibility and wearability, there were differences depending on whether devices were put on correctly, but the participants preferred products that did not wholly block external sounds. For aesthetics, participants preferred small and cutting-edge designs. Interest was noticeable among those who had not used the devices before, and for stability, the neckband-type was the most preferred. Based on the results we suggest designing small cutting-edge designs and button-type assist devices, not blocking the external sound, providing a participation program, simplifying device functions, and establishing a method that can be combined with and stored in clothes and a delivery method that can signal danger.

• 한국습지학회지
• /
• 제10권3호
• /
• pp.87-97
• /
• 2008

본 연구는 현재 대부분의 자연형 하천에 적용되는 프리캐스트 호안블록 대신 현장 타설식 일체형 블록시스템을 개발하고 수리특성분석을 위하여 수리모형 실험을 실시하여 수위와 유속의 변화를 통하여 호안 적용성을 검토하였다. 기존의 프리캐스트 불록은 홍수 시 빠른 유속과 집중하중에 유실 및 탈락의 문제점이 나타나고 있으나 이를 보완한 일체형 호안블록 시스템은 홍수시나 수충부에 적합한 호안식생블록 시스템이다. 수리모형실험에서는 성덕댐이 위치한 보현천의 하도에 1/50 축척으로 모형을 재현하고 설계홍수량을 방류하는 조건으로 하도에서 원형과 개발된 블록의 식생유무에 대한 흐름 및 특성의 변화를 검토하였다. 검토결과, 설계홍수량 $200m^3/sec$에서 유속 저감 평균 10.1%, 수위 상승 평균 17.8%의 실험 결과를 얻었다. 연구(II)에서는 수치모형실험을 통하여 실험결과를 검증하고자 하였다.

• 한국산학기술학회논문지
• /
• 제16권4호
• /
• pp.2424-2429
• /
• 2015

유압 피스톤 펌프에서, 고속 상대운동을 하는 실린더 블록과 밸브 플레이트는 누설 및 마찰 손실의 최적화를 위해 극단적으로 제어되어야 하는 특성을 가지고 있으며, 내압 특성 설계는 고압 성능에 매우 중요하지만 이에 대한 응력 해석에 관한 연구가 활발하게 수행되지는 않았다. 따라서 본 논문에서는 CATIA V5를 사용한 정적 응력 해석을 통하여 사판식 유압 피스톤 펌프의 실린더 블록과 밸브 플레이트의 응력과 변위를 해석하고자 하였으며, 실린더 블록의 최대응력은 실린더 뒷부분 동 재질의 접합 소재에 발생하며, 축방향에 비해 반경방향 작용압력이 응력과 변위에 더 큰 영향을 주고, 응력은 약 66%, 변위는 약 30% 더 크게 나타났다. 밸브 플레이트의 경우 재질 및 형상에 대한 검토가 요구됨을 알 수 있었다.

• 한국지반신소재학회논문집
• /
• 제8권3호
• /
• pp.45-52
• /
• 2009

최근 국내에서는 시공성 및 경제성이 우수하고, 수려한 경관을 연출할 수 있는 보강토옹벽의 적용이 급증하고 있는 추세이다. 일반적으로 블록식 보강토옹벽 시공시 전면블록과 보강재 사이의 연결은 블록에 미리 형성시킨 돌기(전단키형 방식) 또는 플라스틱 핀(핀형 방식)을 이용하여 보강재를 블록에 정착시키는 방식으로 이루어지고 있다. 그러나 이와 같은 연결방식은 시공중 보강재에 부분적인 손상의 원인이 되며, 이로 인해 보강토옹벽의 안정성에 문제를 야기시킬 수 있다. 따라서 본 연구에서는 기존 연결방식의 문제점을 해결하고자, 안정성을 보다 높이고 경제성은 기존 방식과 유사한 I형 연결장치를 이용한 전면블록/지오그리드 보강재의 연결방법을 개발하였으며, 현장 적용을 위하여 연결강도 특성을 평가하였다.

• 한국물환경학회지
• /
• 제34권3호
• /
• pp.293-300
• /
• 2018

Ihe purpose of this study is to evaluate the effects the storage type of permeable concrete block paving (ST-PCBP) have on runoff reduction and infiltration increasement at Andong Maskdance Festival Square. This was accomplished using the NRCS-curve number method over the last 10 years. Two different scenarios were developed in this study for low impact development (LID) design. For the $1^{st}$ scenario, the walking path and parking lot were install using the ST-PCBP and runoff from the inline skating rink ($3,808m^2$) and lawn ($11,191m^2$) were routed to the ST-PCBP, but the rooftop runoff flowed into the storm water drainage system. For the $2^{nd}$ scenario, one of the non-structural BMPs, disconnected impervious surface (DIS), was applied so additional runoff from rooftop would enter the ST-PCBP. It was determined that ST-PCBP could significantly reduce surface runoff from the study area and increase infiltration with 71% and 88% of surface runoff reduction and 151% and 215% of infiltration increasement for scenarios 1 and 2, respectively. The effect of LID in the $2^{nd}$ scenario was better than the $1^{st}$ scenario, therefore DIS in conjunction with ST-PCBP could be a more cost-effective LID application.