• 한국식품조리과학회지
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• 제24권1호
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• pp.23-30
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• 2008

Sulgidduk samples made with additions of 2, 4, 6, 8, and 10% Houttuynia cordata Thunb. powder, and a control were examined for quality characteristics such as moisture content, water activity, color, gelatinization properties, textural characteristics, and sensory qualities in order to determine the optimal ratio of Houttuynia cordata Thunb. powder in the formulation. The moisture contents among the samples ranged from 41.98% to 44.97%, and increased as the content of Houttuynia cordata Thunb. powder increased. The water activities of the samples were not significantly different. As the Houttuynia cordata Thunb. powder content increased, the redness and yellowness of the samples also increased, but lightness decreased. For the gelatinization properties, the additions of Houttuynia cordata Thunb. powder caused decreases in peak viscosity (P) and holding strength viscosity (H). Furthermore, final viscosity (F), setback, and time to peak viscosity decreased with increasing Houttuynia cordata Thunb. powder content; however, breakdown and temperature to peak viscosity were not significantly different among the samples. Hardness and gumminess decreased with increasing Houttuynia cordata Thunb. powder content, and adhesiveness, cohesiveness, chewiness, and resilience also tended to decrease; however, springiness was not significantly different among the samples. In the consumer acceptance test, as the content of Houttuynia cordata Thunb. powder increased, the scores of all evaluated characteristics decreased; while the characteristic intensity ratings showed the reverse effect, and the 2 and 4% Houttuynia cordata Thunb. powder samples obtained fairly good scores. In conclusion, the results indicate that adding $2{\sim}4%$ Houttuynia cordata Thunb. powder to Sulgidduk is optimal, providing good physiological properties and reasonably high overall consumer acceptability.

• 한국건축시공학회지
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• 제22권4호
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• pp.337-345
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• 2022

해안지역 초고층 콘크리트 건축물 매트기초는 상하층 응력발생으로 인한 결함예방과 원활한 공정관리를 위해 일반적으로 일체타설이 요구되지만 일체타설의 경우 수화열에 의한 온도응력 균열 발생의 우려가 있으며 다짐에 대한 시공성을 확보하기 위해 높은 수준의 자기충전성의 콘크리트 배합이 필요하다. 본 연구에서는 이러한 요구성능을 만족할 수 있도록 고성능 분사제와 혼화재의 사용량을 실험변수로 배합 실험을 통해 최적량을 도출하고자 하였다. 배합 변수별 결과분석을 통해 단위수량은 155kg/m³, 결합재에서 시멘트 비율 18% 일 때 굳지 않은 콘크리트 물성 및 강도발현 목표값을 만족하는 것으로 나타났다. 4성분계(시멘트 18%, 슬래그미분말 50%, 플라이애시 27%, 실리카흄 5%)가 사용되었다.

• 한국세라믹학회지
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• 제45권8호
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• pp.439-442
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• 2008

A series of reaction-sintered SiC was fabricated from preforms with varying volume fractions of two resin-coated SiC particles of different sizes (63 and $18{\mu}m$). The electrical resistivity and mechanical strength were eventually optimized at the small particle volume fraction of $0.3{\sim}0.4$, at which point the porosity of the preform was minimized. This study experimentally proves that additional processes after the formation of the preform, such as silicon infiltration and reaction sintering, do not apparently alter the optimum volume fraction of the preform packing, predicted by an existing analytical model based on solid packing. Thus, the volume fraction of particles of different sizes can be determined practically through the solid packing model to fabricate RSSCs with optimal properties.

• 한국생산제조학회지
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• 제22권3호
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• pp.414-420
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• 2013

Research on decreasing the weight of composite sandwich panels is in progress. This paper reports the experimental results for the mechanical behavior of a composite sandwich panel. The skins of sandwich panels were made of glass fiber sheets and plywood matrix composites. Their interior layers consisted of glass fiber pultrusion pipes and gold foam. Experimental tests were performed to obtain the mechanical properties and complex mechanical behavior. Before fatigue tests, tensile tests and 3-point bending tests were carried out to obtain the optimal design and determine their strength and failure mechanisms in the flat-wise position. After the static test, a fatigue test were conducted at a load frequency of 5 Hz, stress ratio (R) of 0.1, and endurance limit for the S-N curve. It showed that the failure modes were related to both the core design and skin failure.

• 한국수산과학회지
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• 제25권2호
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• pp.93-102
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• 1992

In order to reduce long preparating time for alkali pretreated B-type gelatin, enzyme pretreatment was tried on flounder(Limanda aspera) skin for I-type gelatin. The optimal extraction conditions of the B-type gelatin were 9 folds of added water with material(w/w), 3 hrs of extraction time, $60^{\circ}C$ of extraction temperature and pH 5. The maximum amount of I-type gelatin was extracted at $60^{\circ}C$ for 3 hrs using water controlled to pH 6.0(material : water= 1:9, w/w). The yields of the B- and E-type gelatin were $64.2\%\;and\;59.2\%,$ respectively. The B-type was superior to the B-type in physical properties such as jelly strength, viscosity and electric conductivity. Molecular weight of B-type was so far larger than that of the E-type due to different pretreatment method. Hydrolysis ratio of the E-type was higher than that of the B-type because of its molecular weight. Results suggest that B-type product would be better than I-type as fish skin gelatin but E-type was desirable in hydrolyzate preparation.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2002년도 Proceedings of the International Welding/Joining Conference-Korea
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• pp.803-808
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• 2002

A computer-aided alloy-designing technique to develop the insert metal for transient liquid phase (TLP) bonding was applied to high aluminum Ni-base superalloys. The main procedure of a mathematical programming method was to obtain the optimal chemical composition through rationally compromising the plural objective performances of insert metal by a grid-search which involved data estimation from the limited experimental data using interpolation method. The objective function Z which was introduced as an index of bonding performance of insert metal involved the melting point, hardness (strength), formability of brittle phases and void ratio (bonding defects) in bond layer as the evaluating factors. The contour maps of objective function Z were also obtained applying the interpolation method. The compositions of Ni-3.0%Cr-4.0%B-0.5%Ce (for ${\gamma}$/${\gamma}$/${\beta}$ type alloy) and Ni3.5%Cr-3.5%B-3%Ti (for ${\gamma}$/${\gamma}$ type alloy) which optimized the objective function were determined as insert metal. SEM observations revealed that the microstructure in bond layers using the newly developed insert metals indicated quite sound morphologies without forming microconstituents and voids. The creep rupture properties of both joints were much improved compared to a commercial insert metal of MBF-80 (Ni-15.5%Cr-3.7%B), and were fairly comparable to those of base metals.

• 한국정밀공학회지
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• 제28권8호
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• pp.915-928
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• 2011

Titanium for dental implant application has the superior properties of biocompatibility, specific strength, and corrosion resistance. However, it is extremely difficult to find a suitable surface treatment method for sufficient osseointegration with biological tissue/bone cell and implant surface. Surface treatment technology using laser has been researched as the way to increase surface area of implant. In this study, to develop the surface treatment process with improved adhesion between implant and bone cell at the same time for superior biocompatibility, pulsed laser beam was overlapped continuously for scribed surface morphology and determination of friction coefficient. As the results, surface area and friction coefficient was increased over 2 times by the comparison with sand blasting, which is used for the conventional method. In this time, the optimal condition for laser beam power and beam irradiation speed was 13 watt and 50 mm/sec, respectively.

• 한국정밀공학회지
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• 제30권8호
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• pp.878-884
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• 2013

Stereolithography can be classified into two main categories according to the cross-sectional shape: scanning type and projection type. Projection stereolithography has significant advantages when making a layer using a single patterned beam, and results in improved speed and accuracy. To implement relatively low-cost projection stereolithography, we developed a system using a commercially available resin, which cures on exposure to visible light. The optimum photoinitiator was investigated, as well as the mixing ratio. The viscosity, shrinkage, curing depth and tensile strength were evaluated through several experiments on fabricated three-dimensional structures, and thus an optimal resin selection system was developed.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.339-342
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• 2000

Recently, the importance of the conutermeasures for waste materials has pointed out. Waste glass is also one to waste materials used for the recycling in construction sites. The crushed waste glass has been used to make a glass polymer composite that can be applied for sewer, storm drain pipe and interlocking block, etc. In this study, the crushed waste glass is explored with the possibility of recycling it, as a substitute for fine aggregates. The prepose of this investigation is to improve the strengths and acid resistance of the UP mortars using crushed waste glass. The UP mortars are prepare with blast furnace slag fly ash filler. the UP-fine aggregate ratios the crushed waste glass replacements for fine aggregate are tested strengths before and after immersion(H (아래첨자2)SO(아래첨자4) 10%), weight change and acid resistance are also tested. From the test results, the relative strength or UP mortars using fly ash as filler are found to be somewhat superior to that of the UP mortars using blast furnace as filler, And a UP mortar with fly ash as a filler, a UP-fine aggregate ratio of 15% and a waste glass replacement if 50% for fine aggregate is recommended as optimal mix proportion of UP mortar using crushed waste glass. Accordingly, it is enough to assure the use of the crushed waare glass as an aggregate for the production of UP mortar.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2003년도 학술.기술논문 발표회
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• pp.27-31
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• 2003

To maintain serviceability of concrete structure more than proper it is necessary not only predict service life through periodical monitor but also need monitoring system to recognize optimal time and method for repair. Recently, CPGFRP, replacing some GFRP with CF, is developed and used for monitoring concrete fraction. But dramatic resistance change of CPGFRP is showed below 0.5% strain and it is not small strain in terms of monitoring micro crack in concrete. In other word, monitoring with CF is not suitable in low stress hut hight stress. In this study, we accessed applicable possibility and reliability of CPGFRP composite as monitoring sense that is proved very sensitive to stress through domestic and oversea previous study. CPGFRP composite plays a role in specimen like steel and increases flexural strength. CPGFRP composite shows resistance increasement in micro crack. In particular, CPUFRP is more sensitive than strangage in low stress. Resistance change ratio curve is very similar to strain curve so sensitivity and reliability is very excellent to monitor concrete fracture.