• International Journal of Highway Engineering
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• v.4 no.1 s.11
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• pp.149-159
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• 2002

This study was performed to estimate the high-speed direct tensile strength(DTS1), low-speed direct tensile strength(DTS2) , indirect tensile strength(ITS) resilient modulus(MR) and stiffness index(SI) of sand asphalt mixture based on the absolute viscosity, kinematic viscosity, penetration, softening point and PG grade of binder. DTS2 showed higher correlation with the physical properties than other properties of mixture, and the next was DTS1, ITS, SI and MR in order. Among binder properties, PG grade showed the highest relation with DTS2. Therefore. it was found that the high DTS mixture could be made when the binder with a high PG grade was used. However, since the individual physical property showed a relatively low correlation, various properties were used together in regression analysis. The estimation models of DTS and ITS were over 0.99, respectively. R2 of MR and SI estimation models were over 0.91 and 0.93, respectively. It was concluded that mechanical properties could be estimated with a high coefficient of determination from those physical properties.

• Journal of the Korean Society of Food Science and Nutrition
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• v.44 no.3
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• pp.449-454
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• 2015

This study investigated the quality of noodles added with different amounts of freeze-dried fish scale collagen mixture powder (FDCMP). Freeze-dried fish scale collagen mixture was prepared by mixing ingredients (fish scale collagen : herb extracts : dextrin : distilled water=1:0.75:0.25:2), which were freeze-dried. Noodles were prepared by adding 0.5, 1.0, 1.5, and 2.0% (w/w) FDCMP based on flour weight. Cooked noodle weight and volume decreased with increasing amount of FDCMP, whereas turbidity of soups significantly increased. The water-binding capacity of FDCMP was higher than that of flour. Uncooked and cooked noodles showed reduced L values as well as increased a and b values increasing amount of FDCMP in the flour composite. Hardness and chewiness of cooked noodles significantly decreased with increased FDCMP content. Adhesiveness, cohesiveness, and gumminess increased with increased FDCMP content. Springiness and resilience were not significantly different between the control and FDCMP group. Finally, sensory evaluation results indicated that texture, mouthfeel, and overall preference of noodles containing 0.5% FDCMP were higher compared to those of the other samples. Based on cooking properties and sensory evaluation, freeze-dried fish scale collagen mixture powder up to 0.5% could be substituted for wheat flour to improve noodle quality.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2018.06a
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• pp.87-87
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• 2018

다이아몬드 상 탄소(diamond-like carbon, DLC)는 상당량의 $sp^3$ 결합을 가지는 비정질 탄소(a-C) 또는 수소화 비정질 탄소(a-C:H)로 이루어진 준안정 형태의 탄소이다. DLC는 전기 저항과 굴절률이 높고 화학적으로 다른 물질과 반응하지 않으며, 마찰계수가 낮고 경도가 높아 자기 디스크, 광학 소자 등의 다양한 분야에서 적용되고 있다[1,2]. 또한 다이아몬드에 비해 상온에서 성장이 가능할 정도로 합성온도가 낮아 적용 기판의 제한이 거의 없고, 증착 방법과 조건에 따라 탄소 결합의 다양성과 비정질성이 변화하기 때문에 넓은 범위의 특성을 얻을 수 있는 장점이 있다. 지금까지 DLC 박막의 광학적 특성, 특히 굴절률, 광학적인 에너지 밴드 갭, 자외선과 적외선 투과성에 대해서는 많은 연구가 진행되었으나 가시광선의 투과성에 대한 연구는 제한적이며[4], 가시광선 투과도 개선에 대한 연구는 전무하다. 본 연구에서는 ITO 기판 위에 DLC를 합성하고 기계적 특성과 가시광선 영역 투과도를 조사하였다. RF-PECVD(radio frequency plasma enhanced chemical vapor deposition) 방법에 의해서 $C_2H_2+Ar$ 혼합 가스 비율과 $C_2H_2+N_2$ 혼합 가스 비율을 변화시켜 ITO 기판 위에 DLC 박막을 합성하였다. 공정 압력과 rf-power, 증착시간, 기판온도는 0.2 torr, 40 W, 5 분, $50^{\circ}C$로 고정하고, 공정 가스는 $C_2H_2+Ar$과 $C_2H_2+N_2$가 200 sccm이 되도록 비율을 변화하였다. $C_2H_2:Ar$과 $C_2H_2:N_2$의 비율은 180 : 20, 160 : 40, 140 : 60, 120 : 80, 100 : 100이 되도록 가스의 유량을 조절하였다. 투과도는 가시광선(380 ~ 780 nm) 범위에서 측정하였고 두께와 표면조도는 AFM으로 측정하였다. 투과도는 $C_2H_2+Ar$의 Ar 가스 비율이 증가할수록 증가해 140 : 60일 때 최댓값을 나타낸 후 다시 감소하였다. $C_2H_2+N_2$ 투과도는 $N_2$ 가스 비율이 증가할수록 감소하는 경향을 나타내었다. 표면 거칠기는 $C_2H_2+Ar$ 혼합 가스를 사용한 경우의 Ar의 가스 비율이 증가할수록 증가하였다. 그러나 $C_2H_2+N_2$ 혼합 가스를 사용한 경우에는 $N_2$ 가스의 혼합 비율이 증가할수록 감소하였다.

• Journal of Marine Bioscience and Biotechnology
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• v.2 no.4
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• pp.250-256
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• 2007

The present study purified two noncyclic triterpenoids, compound 1 and compound 2, that intervene interaction of ICAM-1 and LFA-1 from ethanol extracts of Alpinia katsumadai. The compound 1 and 2 inhibited adherence of sICAM-1 to THP-1 cells with an $IC_{50}$ of $7.59{\mu}g/m{\ell}$ 및 $6.98{\mu}g/m{\ell}$, respectively, without affecting viability of the cells. The compound 1 and 2 also inhibited interaction of CHO-ICAM-1 cells with THP-1 cells with an $IC_{50}$ $6.7{\mu}g/m{\ell}$ 및 $5.5{\mu}g/m{\ell}$, respectively. These findings suggest that the noncyclic triterpenoids from Alpinia katsumadai have inhibitory activities against cell adherent molecules. The present study proposes that noncyclic triterpenoids from Alpinia katsumadai can applied to therapeutic approaches to the diseases that are associated with adhesion of inflammatory cells.

• Journal of Life Science
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• v.17 no.7 s.87
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• pp.931-936
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• 2007

The aim of this study was to evaluate the effects of Codium Fragile(CF) extract on the collagen content and collagen cross-link content of the connective tissues, alkaline phosphatase activity and calcium levels of serum in ovariectomized estrogen-deficient rats. Three groups were surgically ovariectomized. The fourth group was sham operated. Sprague-Dawley female rats were randomly assigned to the following groups : sham-oper-ated rats(Sham), ovariectomized control rats (OVX-CON), ovariectomized rats supplemented with CF at 50 mg/kg body wt and 200 mg/kg body wt, respectively The CF were orally administrated at 1mLa day. The ovariectomy caused a decreasing in collagen content in bone, cartilage, skin and lung tissues. However CF groups, supplementation with Codium Fragile extract, increased in collagen contentin bone and cartilage tissues than OVX-CON group. Fyridinoline content in cartilage collagen was de-creased by ovariectomy but supplementation with the CF extracts was similarly increased to Sham. Alkaline phosphatase activity on serum of CF groups decreased than OVX-CON group. These results suggest that CF supplementation prevents post-menopausal bone loss, thus it may be used possibly to improve the quality of life in menopausal women.

• Journal of the Society of Naval Architects of Korea
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• v.29 no.4
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• pp.193-201
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• 1992

A new equivalent curved beam theory is developed for the analysis of the corner part of ship structures, in which effects of distributed loads and asymmetricity with two or three connected parts are considered. Equivalent loads are obtained from equilibrium conditions between the distributed loads and the member forces and moments at the ends of curved beam. And an equivalent curved beam for the asymmetric structure is obtained by superposing the equivalent symmetric parts which have equivalent stiffness. From the sample calculation, it is found that the results of the new equivalent curved beam theory are well agreed with those of finite element method using membrane elements with little computing time and sufficient accuracy.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.5
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• pp.3074-3078
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• 2014

We implemented a dual-band slot-coupled patch (SCP) antenna for the external access point (AP) of the wireless local area network (WLAN) band. The antennas consist of two radiators on three layers. The first radiator is a slotted bow tie antenna operating at the 2.4-2.483 GHz band. The second radiator is a patch antenna with parasitic elements operating at 4.095-5.845 GHz. The high gain and broad bandwidth is important element of wireless access. To enhance the bandwidth, a coupled feeding was used in the first radiator and a parasitic patch was used in the second radiator. We used a parasitic patch and chock to improve the directivity and isolation in both radiators. The porposed antenna was designed by EM simulation tool and measured. The S11 of the antenna was less than -11dB (VSWR 1.8:1) at operating frequency. The peak gain was more than 6 dBi in the first antenna and more than 8 dBi in the second antenna.

• Journal of Adhesion and Interface
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• v.22 no.4
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• pp.136-143
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• 2021

Polyurea has been investigated as a polymer matrix for composite materials because of its high mechanical strength. Although polyurea has a similar chemical structure to polyurethane, it has much higher strength and durability. In this study, the fabrication of polyurea composites reinforced with carbon nanotube (CNT) and graphene oxide (GO) is demonstrated to enhance the tensile strength of the glass fibers composite. Using FTIR and Raman spectroscopies, the chemical structures of polyurea, CNT, and GO are investigated. As a result, spectroscopy analysis reveals that the chemical structure of CNT, GO, and polyurea is maintained during the fabrication of the composite structure. Scanning electron microscopy reveals the uniform distribution of CNT and GO across the polyurea matrix. The reinforcement of 1 wt% CNT in polyurea enhances the tensile strength of CNT/polyurea composites. In contrast, the reinforcement of GO in polyurea induces the degradation of the tensile strength of GO/polyurea composites.

• Journal of the Korean Geotechnical Society
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• v.24 no.7
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• pp.61-73
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• 2008

Piles of a bridge pier are connected with the column through the pile cap (footing). Behavior of the pile foundation can be different according to the connection method between piles and the pile cap. Connection methods between pile heads and the pile cap are divided into two groups : rigid connections and hinge connections. Domestic design code has been specified to use rigid connection method for the highway bridge. In the rigid connection method, maximum bending moment of a pile occurs at the pile head and this helps the pile to prevent the excessive displacement. Rigid methods are also good to improve the seismic performance. However, some specifications prescribe that conservative results through investigations of both the fixed-head condition and the free-head condition should be reflected in the design. This statement may induce an over-estimated design for the bridge which has high-quality structures with casing covered drilled shafts and the PC-house contained pile cap. Because the assumption of free-head conditions (hinge connections) is unreal for the elevated pile cap system with multiple piles of the long span sea-crossing bridges. On the other hand, elastic displacement method to evaluate the pile reactions under the pile cap is not suitable for this type of bridges due to impractical assumptions. So, full modeling techniques which analyze the superstructure and the substructure simultaneously should be performed. Loads and stress state of the large diameter drilled shaft and the pile cap for Incheon Bridge which will be the longest bridge of Korea were investigated through the full modeling for rigid connection conditions.

• Journal of Digital Convergence
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• v.11 no.12
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• pp.345-352
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• 2013

In this paper, a depth estimate method is proposed using GPU(Graphics Processing Unit) in monocular image. a monocular image is a 2D image with missing 3D depth information due to the camera projection and we used a monocular cue to recover the lost depth information by the projection present. The proposed algorithm uses an energy function which takes a variety of cues to create a more generalized and reliable depth map. But, a processing time is late because energy function is defined from the various monocular cues. Therefore, we propose a depth estimate method using GPGPU(General Purpose Graphics Processing Unit). The objective effectiveness of the algorithm is shown using PSNR(Peak Signal to Noise Ratio), a processing time is decrease by 61.22%.