• Land and Housing Review
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• v.12 no.4
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• pp.119-125
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• 2021

The study presents the ductility reinforcement effect of the RC bending member using the CFRP Grid as an experimental result. Experimental variables include a non-reinforced RC bending member (ORI), a bottom reinforced RC bending member (REB), and an RC bending member reinforced at the bottom and side (REBS). The experiment was carried out with four points bending test. As a result of the experiment, it was confirmed that the maximum bending strength increased by 17-20% through reinforcement. In addition, the ductility index calculation results confirmed that the ductility index of REB and REBS increased by 2 and 3 times, respectively, compared to the ORI.

• Journal of the Korea Concrete Institute
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• v.16 no.4 s.82
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• pp.477-484
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• 2004

As a part of durability improvement of concrete-structure, penetrating water repellency of liquid type is applied to concrete surface. Besides, a related standard is made recently, but the standard has been prescribe for initial settlement state of penetrating water repellency of liquid type, to the exclusion of performance variation depending time and outdoor environment factor. For measurement of performance variation, we measured the weight of outdoor exposure specimen every regular intervals and check a measured value against a measured value of different condition specimen. Moreover, after the application of penetrating water repellent, measured a adhesive strength in tension between cement-polymer modified waterproof coatings and surface of specimen. The applied penetrating water repellent is a emulsified silicon type with a deep penetration depth. In view of the results so far achieved, the more a Quantity of application and active solid content does get, the deeper penetrating water repellency of emulsion type Penetrate get longer and supplied moisture increase in quantity, a penetrating water repellency of liquid type penetrates more deep, but a quantity of water absorption increase gradually. Perhaps this result is caused by a reduction of active solid content on concrete surface, because active ingredient is moved into the concrete by dissolution.

• Korean Journal of Optics and Photonics
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• v.8 no.4
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• pp.340-344
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• 1997

We proposed and demonstrated a tunable wavelength optical add/drop multiplexer(OADM) employing piezoactuated fiber grating pairs and polarization beam splitters. We used piezostack act as a fiber stretcher, using the fact that the resonant wavelength of the grating can be controlled by the axial strain along the fiber grating. The polarization controlled configuration showed high stability because the reflected signals from the two identical gratings are dropped or added not by interference but by polarizations of the beams. We could add and drop not noly 1549.3nm signal channel(original gratings), but also 1550.1nm(tuned gratings) with PZT actuators and in both cases, we found that the rejection of adjacent channels was more than -26dB, and signal leakage at the gratings was less than -34dB.

• Polymer(Korea)
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• v.34 no.5
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• pp.474-479
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• 2010

We developed laminated cylindrical scaffolds composed of poly(lactide-co-glycolide)(PLGA) and keratin, and investigated their potential for tissue engineering and disk regeneration. The scaffold was designed to have two parts, i.e. inner cylinder and outer disk, to mimic a natural disk. The outer disk was composed of PLGA and the inner cylinder was prepared using PLGA film or PLGA/keratin hybrid film. In this study, we investigated the effects of keratin on the growth and proliferation of annulus fibrous(AF) cells in the cylindrical scaffolds. Scaffolds containing PLGA/keratin films showed a significantly higher cell proliferation and expression of collagen I and II than the counterpart with PLGA films. Keratin containing scaffolds also exhibited an excellent mechanical strength, demonstrating that keratin influences the proliferation of annulus fibrous cells. The results provide valuable information on PLGA/keratin films for tissue engineered disk regeneration.

• Korean Journal of Microbiology
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• v.47 no.1
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• pp.1-6
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• 2011

Inefficiency of in vivo gene transfer using currently available vectors reflects a major hurdle in cancer gene therapy. Both viral and non-viral approaches have been described to improve gene transfer efficiency but suffer from a number of limitations. Here we tested an adenovirus carrying the small peptide ligand derived from heregulin${\beta}$ EGF-like domain onto fiber, the adenoviral capsid protein, to deliver transgene to ovarian cancer cells which overexpress ErbB, the cognate receptors for heregulin. The attachement of 53 amino acids to fiber didn't affect on the fiber's trimer structure that is critical for the viral entry to cells. The fiber-modified adenovirus can mediate entry and expression of a ${\beta}$-galactosidase into cancer cells in an increased efficiency compared the unmodified adenovirus. Particularly, the gene transfer efficiency was improved up to 5 times in OVCAR3 cells, an ovarian cancer cell line. Such transduction systems hold promise for delivering genes to ErbB receptor overexpressing cancer cells, and could be used for future cancer gene therapy.

• Journal of the Korean Society for Advanced Composite Structures
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• v.2 no.2
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• pp.7-12
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• 2011

Presently, composite method for steel and concrete is often used the stud. Steel properties of composite column could be changed by increasing of welding. The changed properties is possibly to cause local-buckling. Composite column had a large effect by slip instead of pull-out force in comparison composite girder. Improvement of adhesive force had effect by contact area rather than height of stud in composite column. This paper proposed new type of stud and analyzed performance through experimental study. This method would be effect steel structure with curvature.

• Journal of the Korea institute for structural maintenance and inspection
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• v.21 no.4
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• pp.13-20
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• 2017

Unreinforced masonry buildings are vulnerable to lateral forces, such as earthquakes, owing to the nature of the building materials, yet numerous masonry buildings remain in South Korea. Since the majority of the existing masonry buildings were constructed more than 20 years ago, it is necessary to develop economical reinforcement methods for disaster reduction. In this study, external reinforcement of masonry walls using adhesive stiffeners was proposed as a reinforcement method for such age-old masonry buildings. Six specimens were fabricated with different aspect ratios (L/H = 1.0, 1.3, and 2.0) and used in static load tests to verify the reinforcement effect. The experimental results showed that the masonry walls before and after reinforcement were ruptured by rigid body rotation and slip. In addition, the maximum strength, maximum displacement, and dissipated energy of the walls were shown to increase after applying the adhesive stiffeners, thereby verifying the excellent reinforcement effect. Furthermore, an adhesive stiffener design for unreinforced masonry walls was proposed based on the increased shear strength achieved by using conventional glass fibers. The proposed design can be used as a basis for the application of adhesive stiffeners for unreinforced masonry walls.

• Korean Journal of Agricultural Science
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• v.27 no.1
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• pp.13-19
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• 2000

The external morphology of male and female of Liriomyza trifolii (Burgess) was studied using the scanning electron microscopy (SEM). Three types of sensilla were identified on the funicle of antennae. The trichoid sensilla were most conspicious and distributed with a characteristic sharp structure at the apical end. Basiconic sensilla were showed distal curvature about $13{\mu}m$ long and $1.2{\mu}m$ to $1.4{\mu}m$ in diameter. Grooved sensilla were showed a finger-like projections at the peg apex. The function of these sensilla likely to be olfactory. The mouthparts were adapted for sucking food, and formed a elongate rostrum which was incorporated with labrum. The labrum was a small and flap-like shape. The slender and paired maxillary palp seemed to combine with each other lengthwise to long tube. The tarsus typically consisted of 5 segments, which might be variously modified, principally by thickening or flattening. The segment beared a pair of claws. Beneath the claws, there was a pair of pad-like pulvillia and a bristle-like median empodium. L. trifolii might secreted on the pulvillus and empodium an adhesive substance that enable them to cling to smooth surfaces. Male terminalia was complicated. The name 'aedeagus' seemed the best available general term for the copulatory organ, otherwise, female terminalia was usually relatively simple. This structure was reduced and formed a telescopic, eversible, and tubular ovipositor.

• Proceedings of the Korean Society for Bio-Environment Control Conference
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• 2001.04b
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• pp.100-102
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• 2001

본 연구에서는 온실의 난방에 사용되는 열풍식 난방기 등의 배기 연통에 부착하여 배출되는 가스로부터 열을 회수할 수 있는 장치를 개발함에 있어서 연통과 열회수 장치간의 열 교환 성능을 3가지 상이하게 설계된 열 교환 장치(Fig. 1 참조)에 대하여 실험적으로 비교 분석하였다. Fig. 1-(a)는 열 교회수기 개발을 위해 기존에 사용한 장치로서 회수용 공기의 흐름방향이 배기 연통과 직각을 이룬 형식이며, Fig. 1-(b) 및 (c)는 열 회수 성능 개선을 위해 새로 설계된 형식으로서 각각 열 교환 파이프의 배치형식이 상이하나 회수용 공기의 흐름방향이 180도로 굴곡되는 U-자형 흐름이 이루어지도록 하였다. 실험에 사용된 공기 순환 펜의 용량은 AB-형의 경우에는 최대 25㎥/min이고, C-형 및 D-형의 경우는 공히 최대 42㎥/min으로서 송풍전압 조절장치를 이용하여 풍량을 연속적으로 조절할 수 있도록 하였다. U-자형 흐름형식인 C-형 및 D-형의 경우 흐름 방향의 굴곡으로 인한 마찰저항이 있을 것으로 예상은 했으나 당초 예상했던 것에 비해 마찰 저항이 지나치게 큰 것으로 밝혀졌다. 비록 설계된 열교환 튜브의 배열형식별 열 교환기의 외부 모양이 달라 회수기의 표면을 통한 대류 열 교환이 다소 차이를 보일 것으로 예상되지만 본 연구에서는 열 회수장치에 내장된 열 교환 튜브부분만을 통한 열 회수율을 중심으로 형식간의 성능을 비교하였다. 실험을 통하여 측정된 자료중 대표적인 예는 Fig-2와 같으며, 측정자료를 기준으로 분석된 열회수 성능에 대한 설계형식별 비교 결과는 Table-1과 같으며, 분석된 결과를 요약하면 다음과 같다: 1. AB-형 열회수시스템의 경우, 초기 투자비용과 현재의 농용 전력요금 하에서 에너지 절감규모를 비교하면, 대체로 1년을 전후하여 투자에 대한 보상이 충분히 가능할 것으로 판단된다. 2. C-형 및 D-형 열회수시스템의 경우, 열 회수용 공기의 흐름방향이 동일 공간내에서 180도 굴절됨으로서 저항이 크게 발생되어 송풍 펜의 전압 증가에 따른 유속증가가 미미하였으며, 굴절형의 열교환장치는 비록 열교환면적은 직선형과 유사하더라도 송풍 펜의 공기저항이 커져서 결국 열 회수성능이 기대했던 것만큼 크게 개선되지는 못했다. 3. 송풍펜의 용량은 AB-형에 사용된 용량인 25㎥/min 전후가 적절할 것으로 판단되며, 적정 송풍 펜용량 하에서 열 회수성능은 굴절형이 직선형보다 효과적인 것으로 나타났다. 다만, 곡선형은 물론 직선형에서도 열교환 튜브의 배치밀도, 튜브 길이 및 두께 등의 변화에 따른 최적화 연구가 수반되어야 할 것으로 판단된다.

• 한국HCI학회:학술대회논문집
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• 2008.02a
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• pp.553-558
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• 2008

In this paper, we develop a vibration system which can generate diverse vibration effects in realtime by analyzing signals from the sound output of PC. This system is able to detect the occurrences of particular sounds in order to generate corresponding pre-programmed vibration patterns. It contributes to the improvement of the reality and the immersiveness of games and virtual reality applications. In addition, its advantage is to easily add vibration features to applications which were originally developed without consideration for vibration. Our system consists of an external DSP board for signal processing and a vibration pad which can be put on wrists. It is superior to other sound-driven vibration devices because its DSP board can detect more diverse sounds, has higher performance and does not interfere with PC. Also the wrist-wearable vibration pad is able to generate more realistic vibration than other mouse or joystick type devices.