• 토지주택연구
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• 제1권1호
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• pp.67-73
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• 2010

PHC 말뚝에서 강선을 노출시켜 건축물의 기초판과 연결시키는 기존 강선남김 방식은 강결합과 힌지결합의 중간형태로 공동주택(아파트)과 같은 건축구조물에 흔히 사용되는 방법이다. 그러나 이 방법은 역학적인 성능이 검증되지 않았으며 시공과정도 복잡하다. 이에 본 연구는 기존 관련 연구의 결과를 분석하고, PHC 말뚝의 콘크리트 단면적 대비 강선면적 비인 0.3%를 말뚝 접합부의 최소 철근보강량으로 선정하여 PHC 말뚝과 기초판과의 최적의 철근보강 방법을 말뚝 규격별(PHC 450, PHC 500, 및 PHC 600)로 제시하였다. PHC 말뚝과 기초판 접합부의 역학적 성능(인장강도와 전단강도)을 평가하기 위해 실물크기의 실험을 실시하였다. 그 결과, 모든 경우에 대해 요구강도를 만족하였으며 실제 적용되어도 문제가 없음을 확인하였다. 본 결과는 기존 연구에서 제시되었던 접합부의 철근 보강량보다 그 양이 대폭 감소하는 것으로 나타나 PHC 말뚝 시공 시 원가 절감에도 기여할 것으로 판단된다.

• 한국세라믹학회지
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• 제52권5호
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• pp.366-373
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• 2015

Sol-gel binder was prepared by hydrolysis and condensation reaction using boehmite sol and methyltrimethoxysilane as a function of aging-time. The coating slurry was composed of a plate-shape alumina in the sol-gel binder for the EPD process, in which particles dispersed in the slurry were deposited on the electrode under an electric field due to the surface charge. We studied the effects of three parameters: the content of boehmite, the aging time, and the applied voltage, on the physical, thermal, and electrical properties of the hybrid composite films by EPD. The amount of boehmite was 10 ~ 20 wt% and the aging time was 0.5 ~ 72, with a fixed amount of plate-shape alumina of 10 wt%. The condition of applied voltage was 5 ~ 30 V with a distance of 2 cm between the electrode during the EPD process. We confirmed that a structure of hybrid composite films of well-ordered plate alumina was deposited on the substrate when the film was prepared using a sol-gel binder composed of 15 wt% boehmite with 1 hr aging time and EPD at 10 V. The process shows a weight loss of 7% at $500^{\circ}C$ in TGA and a breakdown voltage of 8 kV at $87{\mu}m$.

• Clinics in Shoulder and Elbow
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• 제21권4호
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• pp.220-226
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• 2018

Background: This study introduces a surgical technique with good clinical outcome useful in the treatment of osteoporotic displaced 3- or 4-part proximal humeral fractures. Methods: From May 2014 to February 2016, 16 patients with displaced 3- or 4-part proximal humeral fractures were treated by application of a locking plate with an endosteal strut allograft via a deltoid splitting approach with a minimum follow-up of 12 months. The allograft was inserted through a fractured gap of the greater tuberosity to support the humeral head and then fixed by a locking plate with meticulous soft tissue dissection to protect the axillary nerve. Surgical outcomes were evaluated by the American Shoulder and Elbow Surgeons (ASES) and visual analogue scale (VAS) scores, radiological imaging, and clinical examination. Fixation failure on radiographs was defined as a >$5^{\circ}$ loss of neck shaft angle (NSA) compared to that on an immediate postoperative radiograph. Avascular necrosis (AVN) of the humeral head was also evaluated. Results: In all cases, complete union was achieved. The ASES and VAS scores were improved to $85.4{\pm}2.1$ and $3.2{\pm}1.3$, respectively. Twelve patients (75.0%) had greater than a $5^{\circ}$ change in NSA; the average NSA change was $3.8^{\circ}$. Five patients (31.3%) had unsatisfactory ranges of motion exhibiting a <$100^{\circ}$ active forward flexion. No axillary nerve injuries or AVN were observed at the last follow-up. One patient was converted to reverse total arthroplasty due to severe pain and functional deficit. Conclusions: Minimally invasive fixation via a locking compression plate and an endosteal fibula strut allograft in Neer classification 3-or 4-part fractures with severe osteoporosis in elderly patients can achieve good clinical results.

• 산업진흥연구
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• 제5권3호
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• pp.105-122
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• 2020

본 연구의 목적은 천궁도 28수(宿)와 낙샤트라에 대하여 고찰해보는 것이다. 천궁도가 어떤 과정을 거쳐서 만들어졌는지 고전 문헌에 기록된 자료들을 살펴보고 28수와 낙샤트라가 어떤 의미를 지니는지 살펴봄으로써 각 개인의 삶에 어떻게 적용될 수 있는지 알아보고자 하였다. 천궁도의 문헌적 고찰을 통해 천궁도가 기원전 1000년 전 바빌로니아인들 사이에 존재했으며 동물의 이름을 붙여서 부르기 시작한 데서 유래된 것으로 알려지고 있다. 아시리아인들이 기록한 점토판인 에누마 아누 엔릴(Enuma Anu Enlil)중 몰아핀(Molapin)에 "황도대는 달의 길"이라고 칭하고 있다. 따라서 천궁도라고 불리는 황도대는 달의 움직임을 통해서 만들어졌다는 것을 알 수 있었다. 또한 달이 지나는 길인 백도(白道)에 28개의 항성이 존재하며 이를 28수(宿)라 한다. 28수(宿)는 인도에서 낙샤트라라고 하며 낙샤트라를 통해서 개인의 타고난 운명을 읽을 수 있는 것이다. 음력의 태어난 달과 날짜를 알면 개인의 낙샤트라를 찾아 타고난 운명의 틀 안에서 가장 나은 삶을 선택할 수 있다. 그러므로 본 연구자는 천궁도와 28수(宿) 그리고 낙샤트라에 대한 문헌을 고찰하고 활용방안을 제시해 보았다. 이 연구 결과가 향후 관련 연구에 도움이 되기를 기대한다.

• 제어로봇시스템학회논문지
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• 제7권1호
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• pp.1178-1186
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• 2001

This paper presents design and analysis of a 6 degree-of-freedom new haptic device using a par-allel mechanism for interfacing with virtual reality. The mechanism is composed of three pantograph mecha-misms that, driven by ground-fixed servomotors. stand perpendicularly to the base plate. Three spherical joints connect the top of the pantograph with connecting bars, and three revolute joint connect connecting bars with a mobile joystick handle. Forward and inverse kinematic analyses have been performed and the Jacobian matrix is derived by using the screw theroy. Performance indices such as GPI(Global Payload Index), GCI(Global Conditioning index), Traslation and Orientation workspaces, and Sensitivity are evaluated to find optimal pa-rameters in the design stage. The proposed haptic mechanism has better load capability than those of the ex-isting haptic mechanisms due to the fact that motors are fixed at the base. It has also wider orientation work-space mainly due to RRR type spherical joints.

• 한국안광학회지
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• 제6권2호
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• pp.59-63
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• 2001

대비 민감도를 측정할 대비 휘도는 두 편광 판의 회전과 spectrophotometer로 측정한 가시광 영역의 투과율 면적(T%nm)을 이용하였다. 2개의 contrast 값으로부터 contrast sensitivity(Cs) 계산은 평균 contrast, $L_{max}$ 및 ${\theta}_{max}$ 값을 일정하게 한 후 $L_{min}$ ${\theta}_{min}$값을 계산하여 얻었다. 실험결과 $L_{max}=4000(T%nm)$, ${\theta}_{max}=44.1^{\circ}$로 고정시키고, Cs값이 2.5 및 100에서 $L_{min}$값은 각각 1333, 2666 및 3920(T%nm)이고, ${\theta}_{min}$값은 각각 56.6, 54.3 및 $45^{\circ}$이다.

• Journal of Welding and Joining
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• 제21권2호
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• pp.57-63
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• 2003

Since new types of vehicles or structures made from thin aluminum alloy are under rapid development and some products are already on the market, welding of aluminium sheet is increasing. MIG(Metal Inert Gas), MIG-Pulse, TIG(Tungsten Inert Gas) welding are the typical Ai welding. MIG welding has the advantage of high speed, but it is difficult to apply to the thin plate, because of bum-through by the high heat input and spatter. MIG-Pulse welding can weld without spatter and burn-through, but when the gap exists at the welding joint, there is quite a possibility of bum-through. TIG welding is difficult to weld at a high speed. AC Pulse welding alternates between DCEP(Direct Current Electrode Positive) and DCEN(Direct Current Electrode Negative). DCEN is higher wire melting rate than DCEP, while lower temperature of droplet than DCEP. In AC Pulse welding, far fixed welding current, wire melting rate increases as the EN ratio increases. For fixed wire feed rate, welding current decreases as the EN ratio increases. Because of these features, the temperature of droplet, the depth of penetration, the width of bead decrease and the reinforcement height increases as EN ratio increases, and these are able to weld at a high speed, lower heat input. It is the purpose of this study that design of AC pulse current waveform for MIG welding of Al sheet and estimation of output characteristic.

• 한국주거학회논문집
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• 제24권6호
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• pp.133-140
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• 2013

This study is to clarify the form of window and door of medieval times house which are no longer in existence, by comparative analysis between literature materials and architectural remains of united Silla and Goryo period. Particularly the window and door form change process of was analyzed, in connection with the change of term which are recorded in literature material. The form and the composition of window and door are the elements which determine the elevation design of architecture and concerned with interior environment. Therefore this study is significant in the sense that it could be used as base data for the study on the reconstruction and interior space of medieval times house. There were ho (戶) and moon (門) as door, and chang (窓) for lighting and ventilation as window. Among these, the window can be divided into fixed and openable. There were two kind of fixed window. One is called chang (窓), and it was covered by silk or paper for lighting. The other is called ham (檻), it was the form of vertical bar window and lighting and ventilation was available. And there were two kind of openable window. One is called ho (戶), which had wooden plate window leaves. And the other is called changho (窓戶), lighting was available in the condition of closing.

• Journal of Biosystems Engineering
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• 제23권2호
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• pp.157-166
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• 1998

In this study. a traveling control system was developed to transfer a machine without an operator in the working zone. The dimension of the system was modelized to design and construct smaller than that of real configuration of a greenhouse. For this system, the fixed path type was used to detect exact position during operating a manless machine. and the X-Y table actuator type to escape a unique path, which had the disadvantage in a fixed path type environment. Based on the results of this research the following conclusions were made : 1. This system used two screws to move toward horizontal direction, and a Plate to reach at any points in the working zone. 2. The software combined the functions of path selection and motor operation to control into one program. The path selection program was a menu driven program written in Visual Basic, and the motor operation program was written in Borland C++ for actuating motors. 3. The path-select mode of the program was used by selecting the desired paths, and the user path-create mode by selecting a random path in the path-selection program. 4. The system proved to be a reliable system for operating a manless machine, since accuracy and precision to reach the positions were less than 1%.

• 소성∙가공
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• 제15권3호
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• pp.206-212
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• 2006

Design programs of tube-sheet for heat exchanger based on the related engineering society codes have been widely used. But it is not easy fer beginners to use the design programs. So we need to develop an easy program for design of tube-sheet for heat exchanger. This paper describes a developed design-program of tube-sheet fur heat exchanger. The developed program was coded on boiler theory and pressure vessel codes, provided by TEMA(Tubular Exchanger Manufactures Association) and ASME(American Society of Mechanical Engineers). Visual Basic, which is convenient for beginners to deal with, was used in the programming. Also a finite element analysis of tube-sheet for heat exchanger was carried to verify this developed program by using a commercial software, ANSYS. In the finite element analysis, tube and tube-sheet of heat exchanger were substituted by solid plate having equivalent properties for convenience of calculation. The thickness of tube-sheet obtained by the developed design-program was in good agreement with that of tube-sheet by FEA.