• Composites Research
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• 제15권5호
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• pp.19-26
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• 2002

본 연구에서는 레이저 계측시스템을 이용하여 복합재료 구조물의 실제결함을 검출하였다. 다양한 하중을 적용하여 충격에 의한 복합재료 적층판의 층간분리, 하니컴 구조에서의 접착분리, 복합재료 적층판의 자유단 층간분리, 그리고 접착조인트 구조의 접착부위 접착부위와 같은 네 종류의 시험편을 제작하였고 ESPI와 전단 간섭계의 레이저 계측시스템으로부터 결함을 검출하였다. 열하중 방법을 통하여 시험편의 표면에 변형을 쉽게 일으켜 결함을 검출하였다. 실험결과 복합재료 구조물의 실제결함을 ESPI와 전단 간섭계로부터 쉽게 검출하였으며 더 나아가 ESPI와 전단 간섭계로부터 다양한 종류의 복합재료 구조물의 결함을 검출하는데 있어서 유용하게 이용될 것으로 사료된다.

• Steel and Composite Structures
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• 제23권2호
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• pp.161-172
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• 2017

A new composite tube connection method called the pre-tightened teeth connection technique is proposed to improve the composite tube connection efficiency. This paper first introduces the manufacturing process of the proposed technique. It then outlines how the mechanical properties of this technology were tested using four test groups. The factors that influence the load-bearing capacity and damage model of the connection were analyzed, and finally, the transfer load mechanism was investigated. The following conclusions can be obtained from the research results. (1) The new technique improves the compressive connection efficiency by a maximum of 79%, with the efficiency exceeding that of adhesive connections of the same thickness. (2) Changing the depth of teeth results in two types of damage: local compressive damage and shear damage. The bearing capacity can be improved by increasing the depth, length, and number of teeth as well as the pre-tightening force. (3) The capacity of the technique to transfer high loads is a result of both the relatively high interlaminar shear strength of the pultruded composite and the interlaminar shear strength increase provided by the pre-tightening force. The proposed technique shows favorable mechanical properties, and therefore, it can be extensively applied in the engineering field.

• 연구논문집
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• 통권26호
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• pp.121-132
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• 1996

The carburising surface modification treatment of the die steel has been used for improving wear resistance and heat cycle strength of the die and preventing a pitting on the surface because the carbides are forming in the matrix during carburising. Generally, the hot forging die was used after quenching-tempering treatment or nitriding after quenching-tempering treatment. The nitriding after carburising on the surface of a hot die steel and a wear resistance die steels was suggested by SOUCHARD, JACQUOT. and BUVRON. This surface modification treatment improved the adhesive and abrasive wear resistance and friction coefficient. The process was introduced to the forging die of stainless steel, titanium alloy steel, alloy and medium carbon steel and the physical properties of the die after the treatment were improved. The surface hardening treatment of the nitriding, the carburising, the boriding, and TD process were used to improved the life time of the forging die. Also, the coating process of PVD, CVD and PCVD were used and the hard chromium plating was occasionally used. Therefore, this study analyzed the effects of the carburising time and the conditions of nitriding on STD61 steel. The case depth, the surface hardness, the forming carbide size and shape during overcarburising process on the die steel were also examined.

• 한국실내디자인학회논문집
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• 제22권5호
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• pp.367-375
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• 2013

Using the 'New material' concept has recently been introduced into the natural characteristics. In the course of such a, Janine M. Benyus has proposed to mimic the characteristics of natural ecosystems to mention the concept of Biomimicry. Process made engineered using technical elements for representing the material properties of Biomimicry such will be acting importantly, This study intends to analyze how new materials applied to 'Biomimicry' characteristics are processed in space. The results were as follows : 1) Processing methods of new materials resulted as 'Forming', 'Surface treatment', 'Bonding', 'Inserting'. These four were divided and analyzed into 'Form', 'System', 'Adaptation'. As a result of this analysis, such significances were shown as 'Forming/Surface treatment/Bonding' in 'Form', 'Bonding' in 'System' and 'Adaptation'. 2) 'Bonding' applied to 'System' of new material can be recycled to be combined with other materials through the existing adhesive material, and present as a solution of 'Sustainable development'. 3) 'Bonding' applied to 'Adaptation' of new material is to impart the ability to react to the environment through the joint, but is characteristic, at this time, using digital and other field technology. It appeared primarily that it can be known to meet the social trends and convergence between fields. Thus, as the finish that are friendly to the environment from the interior design, the results of the study are expected to be utilized in the study of new materials guidelines.

• 센서학회지
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• 제23권3호
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• pp.165-169
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• 2014

An existing infrared (IR) analysis system is generally composed of infrared source, IR focusing lenses, IR detector, and optical chopper. An optical chopper is widely used in combination with lock-in amplifier to improve the signal-to-noise ratio by periodically interrupting incident light beam. During recent years, a few researches on miniaturized optical chopper have been reported to apply to micro-scaled optical systems. In this paper, a micro optical chopper operated by electromagnetic actuation is proposed and applied to a miniaturized micro-scaled optical system operating in IR spectral range. Additionally, the fabrication method of the proposed micro chopper is demonstrated. The proposed micro optical chopper is composed of the polydimethylsiloxane (PDMS) membrane, solenoid, and permanent magnet. The permanent magnet is bonded on the PDMS membrane using an ultraviolet-activated adhesive. The operation of the chopper is based on the attractive and repulsive forces between permanent magnet and solenoid induced by an electrical current flowing through the solenoid. The fabricated micro optical chopper could operate up to 200 Hz of frequency. The maximum operating distance of the chopper with 7mm diameter membrane was $750{\mu}m$ at 100 Hz of frequency.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 추계학술대회 논문집
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• pp.599-602
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• 2002

A novel rapid prototyping (RP) process, an automated transfer type variable lamination manufacturing process (Automated VLM-ST) has been developed. In Automated VLM-ST, a vacuum chuck and linear moving system transfer the plate type material with two pilot holes to the rotation stage. A four-axis synchronized hotwire cutter cuts the material twice to generate Automated Unit Shape Layer (AUSL) with the desired width, side slopes, length, and two reference shapes in accordance with CAD data. Each AUSL is stacked on the stacking plate with two pilot pins using the pilot holes in AUSL and the pilot pins. Subsequently, adhesive is supplied to the top surface of the stacked AUSL by a bonding roller and pressure is simultaneously applied to the bottom surface of the stacked AUSL. Finally, three-dimensional shapes are rapidly fabricated. This paper describes the procedure for generating the cutting path data (AUSL data) f3r automated VLM-ST. The method for the generation of the Automated Unit Shape Layer (AUSL) in Automated VLM-ST was practically applied and fabricated for a various shapes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.432-432
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• 2011

Dry adhesion caused by Nanoscale contact comes up to important scientific issue. Herein, we introduce bendable nanohairy locking fastener system with high shear strength and mechanically flexible backing. The polymeric patches like velcro are composed of an array of straight nanohairs with 100 nm diameter and $1{\mu}m$ height. To fabricate high aspect vertical nanohairs, we used UV molding method with appropriately flexible and rigid polyurethane acrylate material on PET substrate. Two identical nanohairy patches are easily merged and locked each other induced by van der Waals force. Because nanohairs can be arrayed with high density ${\sim}4{\times}10^8/cm^2$, we can obtain high shear adhesion force on flat surface (~22 N/$cm^2$). Furthermore, we can obtian nanohairy locking system with maximum shear adhesion ~48 N/$cm^2$ of curved surface due to flexibility of PET substrate. We confirm the tendency that shear adhesion force increases, as radius of curvature increases.

• The Korean Journal of Pain
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• 제1권2호
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• pp.199-202
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• 1988

Secure fixation is essential for continous epidural catheterization on a long-term-basis. Adhesive tape or surgical knots were commonly used for those patients, but the surgical knot method has a tendency to cause strangulation of catheter. Another invasive technique, subcutaneous tissue tunnelling is more safe than other methods but requires sophisticated technique and time. We employed a simple device using a blood transfusion set for patients who have epidural catheters placed safely un their backs. In 120 patients treated for postoperative and chronic pain by means of this technique, the results were as follows: 1) Five of 120 patients (4.2%) developed backache and pruritus, but there were no instances of respiratory depression, local infection and headache. 2) Nine of 120 patients (7.5%) failed booster-injections, but two cases were due to be non-technical errors. 3) The duration of fixation was 1~3 days in most cases (85%), the longest being for 21 days.

• Current Photovoltaic Research
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• 제5권3호
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• pp.95-99
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• 2017

The interconnecting shingled solar cells method shows extremely high ratio active area per total area and has the excellent potential for high power PV (photovoltaic). Compared to the conventional module, it can have much more active area due to busbar-free structure. The properties of ECA (electrically conductive adhesives) are significant to fabricate the shingled array PV since it should be used in terms of electric and structural connection. Various ECA were tried and characterized to optimize the soldiering conditions. The open circuit voltage of shingled array cells showed a three-fold increase and efficiency was also increased by 1.63%. The shingled array cells used in CE3103WLV showed the highest power and in CA3556HF the lowest curing temperature and very fast curing time.

• Applied Biological Chemistry
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• 제39권2호
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• pp.123-126
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• 1996

도축동물의 대부분 폐기되는 혈액으로부터 기능성 소재를 발굴하고 수질오염을 방지하기 위해서 소, 돼지 도축혈액으로부터 간단하고 신속한 방법으로 혈장 단백질을 분리하는 방법을 개발했고 그것을 혈분접착제로 응용하였다. 혈액을 원심분리한후 혈장단백질은 2% TCA 또는 0.6N HCl을 최종농도가 되게 첨가하여 침전시킴으로써 얻어졌다. 소, 돼지 혈장단백질을 비교 분석하기 위하여 SDA-PAGE를 하였고 얻어진 혈장단백질을 이용하여 혈분접착제로서 합판제조에 사용하여 다른 합성접착제와 접착성 시험을 한 결과 다른 합성 접착제와 비교해서 만족한 결과를 얻었다.