• Proceedings of the Ginseng society Conference
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• 2006.05a
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• pp.13-17
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• 2006

다양한 연구에 따르면, 고려인삼은 허약한 체질, 숙취, 폐경과 월경불순, 초기 당뇨병, 영양실조, 빈혈 및 단백질 부족, 간기능 악화, 각종 독성물질에 기인한 중독, 피로, 추위, 스트레스, 산후조리, 체력쇠퇴 등에 효능이 있음이 알려져 있다. 특히 고려인삼은 혈관 기능을 효과적으로 조절함으로 고혈압, 뇌졸중, 심근경색, 동맥경화, 관절염, 당뇨, 비만 등의 질환을 효과적으로 치료하거나 예방할 수 있는 효능이 있음이 최근 연구에 의하여 밝혀지고 있다. 그러나 고려인삼 약리효능의 표적분자(target molecule)나 생화학적 작용기전(biochemical mechanism)이 세포 및 분자 수준에서 규명되지 못하여 고려인삼이 의약품으로 인정받지 못하고 건강식품으로 분류되고 있어 소비가 한인 흑인 히스패닉 시장에 한정되고 있고, 최근에는 타 경쟁국 인삼에 비해 수출 경쟁력이 약화되고 있는 실정이다. 본 연구에서는 고려인삼 추출물과 효능성분이 혈관내피세포 기능조절에 미치는 효능 및 작용기전을 규명하여 고려인삼이 호발성 혈관질환에 대한 예방 및 치료 효능이 있음을 분자 및 유전자 수준에서 확인하고자 하였다.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.172-176
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• 1999

에폭시 수지의 강인성 향상을 위하여 양말단에 아민 반응기를 가지는 PES-CTBN-PES triblock copolymer를 합성하여 이를 에폭시 수지의 강인화제로 사용하였으며 경화제로는 p-DDS(p-dichlorodiphenylsulfone)를 사용하였다. 또한 공중합체에 의한 물성 향상효과를 CTBN과 PES-NH$_2$의 블렌드에 의한 경우와 비교하였다. 강인화된 에폭시 수지의 물성은 강인성 및 굴곡특성을 측정하여 분석하였으며, 열특성은 DSC, TGA, 및 DMA에 의해 실시되었다. 그리고 강인화된 에폭시 수지의 강인성 향상 mechanism을 규명하기 위하여 파단면을 SEM으로 분석하여 상분리 거동을 고찰하였다. 높은 유리전이온도와 우수한 기계적 물성을 가지는 고성능 기능성 폴리설폰(PES-NH$_2$)과 상용 액상 고무 첨가제인 CTBN을 이용하여 합성된 공중합체를 강인화제로 사용함으로써 열안정성, 탄성률 및 내식성의 감소없이 에폭시 수지의 쳐대 단점인 강인성을 최적 수준으로 개선시킬 수 있었으며 공중합체의 에폭시 수지에 대한 우수한 용해도에 따른 가공성이 향상되었다.

• Journal of the Korean Society for Heat Treatment
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• v.2 no.2
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• pp.1-10
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• 1989

In this study, the specimens of SCM 22 H steel were quenched in oil and water baths at various agitation conditions in order to investigate the effects of quenchants and agitation conditions on the quench-hardening. A multi-channel temperature measurement apparatus was employed to obtain the cooling curves at several predetermined positions of specimens. Microstructural observation and hardness test were also carried out. Computer simulation of heat treating process was carried out using the modified finite difference method. Prediction of thermal history and hardness distribution by 2-dimensional computer analysis was in good agreement with the experimental results. It was found that the quantitative design of heat treating process can be made by the computer aided heat-treating analysis.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2001.10a
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• pp.169-170
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• 2001

등푸른 생선 등에 많은 eicosapentaenoic acid(EPA, $C_{20-5}$ n-3), docosahexaenoic acid(DHA, $C_{22-6}$ n-3)등의 n-3계 지방산은 순환기 계통 질환의 위험인자를 제거해 주거나 혈청내 지질 구성이나 혈소판응집 기능에 변화를 주어 동맥경화증에 유익한 효과를 나타낸다고 알려져 있다. 특히 DHA는 망막 및 두뇌 인지질의 구성성분으로 실험동물의 학습능을 비롯한 뇌기능 향상에 기여한다고 한다. (중략)략)략)

• Magazine of the Korea Concrete Institute
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• v.7 no.3
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• pp.156-163
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• 1995

In the previous study, styrene mdleic dnhydride copolymer(SMA) as synthesized flom styrene and rnale~c dnhydr~de and further redcted with sulfuric acid to obtam water soluble SMA. In thls study, the flow dnd strcngth tests of cement mortar rmxed wth copolymers wele carried out to evaluate the capability of copolymers as high range water reducer for the con crete. It was found from flow exper~ment that the fluidity of cenient mortar rmxed wth sulfonated SMA(SSMAj was larger thdn that mxed ulth amnophenol substituted SSMA (SmSMAj. The decreasing rate of the flow of cement mortar rmxed ulth SSMA and SmSMA was significantly lower than that mixed ulth naphthalene condensate(NSC) The compressslve strength of the hardened cement mortars containing 0.5% copolymers after 28 dys curing was exarmned. 'The compressive strength of hdrdened cement mortar containing SSMA and SmSMA was mcreased up to 31% and 13%, respectively, when omp pared to the plain. As the results, the copolyniers(SSMA and SrnSMA) used in thls study are greatly expected as a good high range water reducers for the concrete.

• Journal of Advanced Marine Engineering and Technology
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• v.35 no.5
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• pp.600-607
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• 2011

Recently, high carbon steel has become essential not only for shipbuilding parts, but also mass production. Its surface has been treated by carburizing, nitriding and induction hardening, but these existing treatments cause considerable deformation and increase the expense of postprocessing after treatment; furthermore, these treatments cannot be easily applied to parts that requiring the hardening of only a certain section. This is because the treatment cannot heat the material homogeneously, nor can it heat all of it. Laser surface treatment was developed to overcome these disadvantages, and when the laser beam is irradiated on the surface and laser speed is appropriate, the laser focal position is rapidly heated and the thermal energy of surface penetrates the material after irradiation, finally imbuing it with a new mechanical characteristic by the process of self-quenching. This research estimates the material characteristic after efficient and functional surface treatment using HPDL, which is more efficient than the existing CW Nd:YAG laser heat source. To estimate, microstructural changes and hardness characteristics of two parts (the surface treatment part, and parental material) are observed with the change of laser beam speed and surface temperature.

• Proceedings of the Korean Society of Dyers and Finishers Conference
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• 2012.03a
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• pp.74-74
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• 2012

섬유 프리프레그(Prepreg)는 강화섬유를 수지에 함침하여 B-stage로 만든 복합재료의 중간성형재료이다. 최종적으로 프리프레그를 금형에 적층하여 가열 가압하여 수지를 경화함으로써 최종제품이 완성된다. 본 연구에서는 직물형 프리프레그를 사용하였는데, 사용되는 직물형태로는 복합재료 성형공정에서 형태안정성이 우수한 평직물과 능직물이 주로 사용된다. 직물형 프리프레그를 사용한 복합재료는 작업성과 형태안정성이 우수하면서 내충격특성이 우수하여 오토바이용 헬멧, 방탄용 헬멧 등에 주로 사용된다. 프리프레그에 요구되는 주요 특성중 하나는 Tack성으로서, 성형 과정에서 프리프레그를 여러 장 적층할 때 적층된 층 간에 미끄러지지 않으면서 잘 고정되어 적층 작업을 원활하게 하는 역할을 한다. Tack성은 수지의 B-stage 경화 후의 점성 거동에 따라 변화될 수 있는 것으로 표면의 끈끈함의 정도로서 알 수 있다. Tack성은 온도에 민감하여 측정 시에 일정한 온도의 유지가 중요하다. 이러한 온도에 대한 민감성 때문에 프리프레그의 저장시 저온에서 저장하는 것이 원칙인데, 상온에 있을 경우 시간경과에 따른 Tack성 변화가 크게 나타나게 된다. 따라서 본 연구에서는 아라미드 섬유와 열경화성수지를 이용하여 프리프레그를 제조하고 이를 상온상태에서 보관 시 일정시간 경과에 따른 Tack성 변화를 알아보고자 하였다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.3
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• pp.1611-1619
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• 2015

This study examined the toughness improvement of a track shoe used as the undercarriage of excavator and bulldozer parts. The excavator is operated under poor conditions, such as the build-up field and quarry. Therefore, the track shoe requires high strength and impact toughness to endure immense shock while at work. The track shoe was made of heat treated boron steel. The sufficient possibility of hardenability with the theoretical Jominy curve for boron steel was confirmed while quenching. The Taguchi orthogonal array experiment method was used to optimize the process variables, such as area reduction ratio and heat treatment conditions (tempering temperature and holding time), to achieve toughness improvement. The toughness of the track shoe increased with increasing area reduction, and a tempering temperature of $210^{\circ}C$ and a tempering time of 80 min are beneficial for improving the toughness of the track shoe.

• Korean Journal of Materials Research
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• v.29 no.12
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• pp.781-789
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• 2019

The prediction of Jominy hardness curves and the effect of alloying elements on the hardenability of boron steels (19 different steels) are investigated using multiple regression analysis. To evaluate the hardenability of boron steels, Jominy end quenching tests are performed. Regardless of the alloy type, lath martensite structure is observed at the quenching end, and ferrite and pearlite structures are detected in the core. Some bainite microstructure also appears in areas where hardness is sharply reduced. Through multiple regression analysis method, the average multiplying factor (regression coefficient) for each alloying element is derived. As a result, B is found to be 6308.6, C is 71.5, Si is 59.4, Mn is 25.5, Ti is 13.8, and Cr is 24.5. The valid concentration ranges of the main alloying elements are 19 ppm < B < 28 ppm, 0.17 < C < 0.27 wt%, 0.19 < Si < 0.30 wt%, 0.75 < Mn < 1.15 wt%, 0.15 < Cr < 0.82 wt%, and 3 < N < 7 ppm. It is possible to predict changes of hardenability and hardness curves based on the above method. In the validation results of the multiple regression analysis, it is confirmed that the measured hardness values are within the error range of the predicted curves, regardless of alloy type.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.35 no.4
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• pp.383-391
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• 2011

The hot-stamping technique is used to manufacture high-strength parts by press forming by heating at a temperature above the Austenite transformation temperature and then rapid cooling. Boron steel, which contains a very small amount of boron, is one of the materials used for hot stamping. The purpose of this study is to show the microstructures and to investigate the mechanical properties under different heat-treatment conditions. The heat treatment of water quenching was conducted at the various temperatures and different elapsed times. These can be practical data useful when boron steels are used for hot stamping. Furthermore, the microstructures and mechanical properties of the spot-welded specimen with coatings and counterpart materials (SPRC 340, SPRC 590) is investigated in order to determine the welding characteristics of boron steel at different welding condition.