• International Journal of Highway Engineering
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• v.6 no.4 s.22
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• pp.35-43
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• 2004

Skid resistance is an important factor that control braking distance and secure safety by preventing slipperiness between tire and pavement surface. Decrease of skid resistance at wet condition may cause fatal traffic accidents. Dirt materials such as sand and do-icings on the road surface also can be a factor for decrease skid resistance. This study makes an investigation into influence of skid resistance between varied cement concrete pavements about surface texturing method(transverse tining, longitudinal tining, exposed aggregate surface texturing method) and wearing condition of pavement surface texture(new constructed pavement's surface, wore pavement's surface) using accelerate concrete pavement wearing tester when remains of dirt material are obtained between tire and road surface on PCC pavement. As dirt material on road surface of concrete pavement, sand, calcium chloride and old oil were used with different amount of each cases.

• Journal of the Korean Magnetics Society
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• v.1 no.2
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• pp.69-73
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• 1991

The effects of disk surface velocity on the microstructures and magnetic properties of ${(Nd_{0.8}Dy_{0.2})}_{12}Fe_{80}B_8$ melt-spun ribbons were investigated. From the X-ray diffraction results. it is confirmed that the lower the surface velocity ($V_{s}$), the better the orientation of c-axis normal to the ribbon plane. The results of magnetic property measurements for the powder solidfied in magnetic field showed that the highest remanence was obtained from the alloy quenched at medium velocity of $V_{s}=14.6m/s$. The remanence of the powder solidfied in magenetic field was about 10 % higher than that of the powder solidfied in non-magnetic field.

• Korean Journal of Materials Research
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• v.8 no.11
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• pp.993-998
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• 1998

In this study TiNi/A16061 shape memory composite is introduced as one of new material using a shape memory alloy. High tensile strength of composite due to compressive residual stress in matrix by the shape memory effect of TiNi fiber can be produced. This composite can remove the tensile residual stress by the difference of coefficients of thermal expansion between fiber and matrix. one of the significant weak point of metal matrix composite. In this paper, shape memory composites are made by squeeze casting. And then, microstructure and fatigue properties of the composites by shape memory effect above inverse transformation temperature A, of TiNi alloy are discussed. The results of the fatigue crack control properties of TiNi/A16061 shape memory composite by a squeeze casting are summarized as follows the effect of fatigue crack propagation control at 363K increases according to the increase of volume fraction and prestrain in composites.

• Journal of the Korean Magnetics Society
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• v.2 no.1
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• pp.44-49
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• 1992

Magnetic properties and microstructures of $Nd_{12}Fe_{80}B_{6}(Nb,\;M)$ (M=Ti/Cu/Ga) melt-spun ribbons prepared by single wheel technique have been studied. The results of microstructural study have shown that Ga is effective for the orientation of c-axis normal to the ribbon plane. The Ga-added melt-spun ribbon, $Nd_{12}Fe_{80}B_{6}(Nb,\;Ga)$, quenched at $V_{s}=17.9\;m/s$ was mostly composed of fine grains of about 30 nm in size with the textured free-side surface. The powder of this ribbon aligned in mag-netic field showd a high remanence of 0.87 T which was about 5 % higher than that of ribbon itself. It is believed that there is a possibility to fabricate a new type of HIREM melt-spun ribbon with highly textured free-side surface.

• The Journal of the Convergence on Culture Technology
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• v.8 no.5
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• pp.685-690
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• 2022

Recent research on soft adhesives has sought to understand in depth how their chemical or mechanical structures interact strongly with living tissues. The aim is to optimally address the unmet needs of patients with acute or chronic diseases. Synergy adhesion, which includes both electrostatic (hydrogen bonds) and mechanical interactions (capillary stress), appears to be effective in overcoming challenges related to long-term unstable bonds to wet surfaces. Here, we report electrostatic and mechanically synergistic mechanisms of adhesion without chemical residues. To infer the mechanism, a thermodynamic model based on custom combination adhesives has been proposed. The model supported experimental results that thermodynamically controlled swelling of hydrogels embedded in elastomeric structures improves biofluidic insensitive on-site adhesion to wet surfaces and improves detachment without chemical residues in the direction of peeling.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2011.11a
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• pp.53-53
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• 2011

자동차용 천연가죽 시트의 제조 공정에서 크롬과 비크롬 Metalic 탄닝제, 식물성 탄닝제, 신탄(Syntan) 및 가지제(Fatliuor) 등의 종류와 함량에 따른 인장강도, 신장율, 정하중 신율, 잔류줄음율 등을 측정하여 특정하중에 따른 콜라겐 섬유 조직의 영구변형율과의 상관관계를 비교 분석해본 결과, 크롬 및 비크롬계 탄닝제에 비해 식물성 탄닝제를 적용하였을 때 조직의 변형율이 적었으며, 리틴닝 공정에서 아크릴계, 레진계 및 단백질계 신탄을 혼합 적용하였을 때 가죽의 배(Belly)부위의 물성 균일화 효과가 우수하였으며, 음이온성 가지제 9%를 사용하여 가죽에 유연성을 부여함으로써 조직이 치밀하고 변형율이 감소되어 내구성이 우수한 결과를 나타내었다.

• Journal of the Korean earth science society
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• v.22 no.6
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• pp.528-547
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• 2001

The blastoporphyritic granite gneiss (BPGN) including much alkali-feldspar megacrysts occurs in Jiri mountains area, southwestern part of Sobaegsan massif, Korea. The BPGN is formed gneiss complexes with other gneisses in Precambrian. The BPGN was named as porphyroblastic gneiss with porphyroblasts of alkali-feldspar megacrysts by other researchers, but the BPGN includes of euhedral alkali-feldspars (microcline), and the boundary with the granitic gneiss represents sharp contact as intrusive relationship. The BPGN mainly composes of alkali-feldspar megacrysts, quartz, plagioclase, K-feldspar and biotite some almandine and accessary minerals are muscovite, chlorite, apatite, zircon and opaques. The alkali-feldspar is microcline with perthitic texture. An content of plagioclases show 30 to 40. Biotites occur two type, one is Brown biotite which shows compositional ranges of Mg/Fe+Mg ratios from 0.38 to 0.52, the other is Green Bt. which is retrograde product. Camels to be various sizes and shapes have composition of almandine with 73 to 80 mole percent, but represent retrogressive zoning from core (X$_{pyr}$: 15.9${\sim}$20.8) to rim (X$_{pyr}$:13.7${\sim}$15.9) to be evidence of retrograde metamorphism. Megacrysts of alkali-feldspar in the BPGN show rectangular shape of euhedral and some become ellipsoidal or spheroidal in shape and the average size up to 20 cm long. The megacryst includes of biotite, plagioclase and quartz, and rarely euhedral apatite as inclusions. In petrochemistry the BPGN represents granodiorite composition, characteristics of peraluminous S-type granitoid and calc-alkaline features.

• Journal of the Korean Society of Marine Environment & Safety
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• v.18 no.6
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• pp.505-513
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• 2012

To determine the concentration of trace metals in the tissues of whale from the coastal ocean of Korea, we measured the concentration of trace metals (Cu, Cd, Pb, As, Zn and Hg) in the organs (liver, intestine, muscle, epidermis and blubber) of minke whale entangled from the eastern coast of Korea in 2009. The highest and lowest concentrations of Cu, Cd, Zn, and Hg were found in the liver and blubber, respectively. In contrast, the highest and lowest concentration of As was found in the blubber and muscle, respectively. The accumulation trend of trace metals in the organs of minke whales was in the order Zn > Cu > As > Pb > Hg > Cd. The concentrations of Cu, As and Zn in liver and epidermic were higher in male than in female, whereas the concentrations of Cu and Pb in intestine and muscle were higher in female than in male. The mature individuals of minke whale were much higher Cd in liver, Cd and Hg in muscle, As and Hg in epidermic and blubber, Cd, As and Hg in intestine than immature individuals of minke whale.

• Korean Journal of Veterinary Research
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• v.38 no.1
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• pp.43-52
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• 1998

서방형 돼지성장호르몬(sustained-release formulation of porcine somatotropin, PST-SR)을 1주 간격으로 6차례 피하 및 근육주사하고 혈액과 조직중의 돼지 성장호르몬(PST)과 insulin-like growth factor 1(IGF-1)의 농도를 측정하여 다음과 같은 결과를 얻었다. 대조군의 혈중 PST와 IGF-1의 농도는 각각 2.41과 95.2 ng/ml 이었다. 1. PST-SR을 투여한 후 PST의 혈중농도는 8시간만에 최대에 도달하여(30 ng/ml) 곧 감소하였다. 혈중농도 반감기(decay half life)는 91~227시간이었다. IGF-1의 혈중농도는 투여후 12시간에 최대에 도달하였으며(165 ng/ml), 이후 서서히 감소되었고 반감기는 77~99시간이었다. 2. 혈중 PST농도-시간의 자료는 제재에서 PST가 유리되는 과정에는 두단계 즉, 투여후 24시간까지의 유리속도가 빠른 단계와 그 이후의 유리속도가 느린 단계가 있음을 보여주었다. 3. 여섯번의 반복투여기간에는 PST의 혈중농도는 투여직후 증가하여 24시간 이후 다음 투여전까지 지속적으로 감소되는 패턴이 반복되었고, 최종투여후 1주일경에는 정상수준으로 회복되었다. 반면에 투여가 반복됨에 따라 매 투여직후의 PST의 혈중 최고치는 다소 증가되는 경향을 보였다(20~40 ng/ml). IGF-1의 혈중농도는 투여가 반복됨에 따라 누적적인 증가현상이 뚜렷하였으며, 이후 2주일후 까지도 정상농도보다 높게 유지되었다(200ng/ml). 임상용량 투여군에서 PST 및 IGF-1의 혈중농도는 투여경로에 따른 차이는 나타나지 않았다. 4. 최종(6번째) 투여후 6, 8, 10, 14일에 조사한 간장, 신장, 소장, 근육, 지방 및 주사부위의 조직중의 PST 농도는 6일째에 이미 대조군 수준으로 회복되었다. IGF-1의 경우 최종투여후 6일에는 간장, 신장, 소장, 지방조직에서 정상보다 높은 농도로 잔류하나 이후 14일까지 모두 대조군 수준으로 감소되었다. 5. 이상의 결과는 본 실험에서 사용된 서방형 PST제제는 최소 1주간 유효성이 유지되며, 동시에 PST는 투여 6일째에, IGF-1은 투여후 14일에 정상수준으로 회복됨을 보여주고 있다.

• Analytical Science and Technology
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• v.20 no.4
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• pp.347-354
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• 2007

A simple and rapid high-performance liquid chromatography assay for the determination of residual novobiocin levels in bovine, porcine, chicken, flatfish and japanese eel muscle has been developed and validated. The separation condition for HPLC/UV was optimized with phenyl hexyl ($4.6{\times}150mm$, $5{\mu}m$) column with 10 mM monobasic sodium phosphate buffer (pH 2.5)/acetonitrile (50/50, v/v) as the mobile phase at a flow rate of 1.0 mL/min and detection wavelength was set at 254 nm. Residues were extracted from tissue by blending with methanol and lipid materials were removed with n-hexane. Then, the methanol extract was evaporated to dryness under a nitrogen stream, reconstituted in the mobile phase. Aliquot of the organic extract was decanted and filtered through $0.45{\mu}m$ syringe filter. The $20{\mu}L$ of the resulting solution was injected into the HPLC system. The calibration ranges were $0.5{\sim}5{\mu}g/g$ and calibration curves were linear with coefficients of correlation better than 0.95. The limits of quantification were $0.5{\mu}g/g$ for all muscles. The recoveries of bovine, porcine, chicken, flatfish and japaneseel muscles were 99.8%, 102.4%, 91.0%, 104.0% and 93.0%, respectively. The procedures were validated according to the CODEX guideline, determining specificity, linearity, accuracy, precision, quantitation limit and recovery.