• Preventive Nutrition and Food Science
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• 제1권1호
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• pp.46-52
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• 1996

Effective method for the preparation of Dongchimi juice was developed by addition of NaCi, sucrose and bydrolytic enzymes before fermentation and addition on Dongchimi juice during fermentation. The radish was ground and suspended in water(1:1, w/v) with addition of spices(garlic, green onion and ginger) followed by fermentation at $25^{\circ}C$. The addition of 2% NaCi and 0.5~2.0% sucrose resulted in significant increase of solid content and it was also improved by the addition of polysaccharide hydrolyzing enzyme during fermentation. When the fermented juices of pH 5.4 of 4.4 were added by 15% of total weight before(pH 5.4 juice)and during (pH 4.4 juice) fermentation, a significant increase in solid content after 24hrs of fermentation was resulted. The combined method of addition of 2% NaCI, 1.0% sucrode, 0.1% Viscozyme and 10% of fermented juice of pH 5.4 and 4.$ before and during fermentation improved solid content, reducing sugar, color and showed little effect on viscosity. The organoleptic characteristics were also improved by the combined method.

• Steel and Composite Structures
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• 제32권6호
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• pp.753-767
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• 2019

Vibration control in mechanical equipments is an important problem where unwanted vibrations are vanish or at least diminished. In this paper, free vibration active control of the porous sandwich piezoelectric polymeric nanocomposite microbeam with microsensor and microactuater layers are investigated. The aim of this research is to reduce amplitude of vibration in micro beam based on linear quadratic regulator (LQR). Modified couple stress theory (MCST) according to sinusoidal shear deformation theory is presented. The porous sandwich microbeam is rested on elastic foundation. The core and face sheet are made of porous and three-phase carbon nanotubes/resin/fiber nanocomposite materials. The equations of motion are extracted by Hamilton's principle and then Navier's type solution are employed for solving them. The governing equations of motion are written in space state form and linear quadratic regulator (LQR) is used for active control approach. The various parameters are conducted to investigate on the frequency response function (FRF) of the sandwich microbeam for vibration active control. The results indicate that the higher length scale to the thickness, the face sheet thickness to total thickness and the considering microsensor and microactutor significantly affect LQR and uncontrolled FRF. Also, the porosity coefficient increasing, Skempton coefficient and Winkler spring constant shift the frequency response to higher frequencies. The obtained results can be useful for micro-electro-mechanical (MEMS) and nano-electro-mechanical (NEMS) systems.

• 한국추진공학회지
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• 제25권4호
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• pp.12-18
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• 2021

본 연구에서는 추력 제어용 추진제 조성 개발을 위해 고 압력지수 추진제를 만들고자 하였다. 프리폴리머로 PCP를 사용하며 니트라민 계열의 산화제인 HMX와 HNIW 기반 추진제를 제조하여 각각의 연소특성을 비교하였다. HMX에 비해 HNIW가 추진제의 연소속도, 비추력 그리고 화염온도에 큰 영향을 준다는 것을 알았다. 또한, AP를 조 산화제로 사용할 경우, 추진제의 연소속도, 비추력 및 화염온도는 미세 AP 함량, 총 고체 함량 그리고 가소제 양이 증가할수록 병행 상승하였으나, 압력지수는 오히려 낮게 나타났다. 그리고, 여러 압력 구간에서 온도에 따른 연소특성 변화를 알아보기 위해 150 psia부터 2,500 psia사이 구간에 대해 PCP/Nitramine/AP 추진제의 연소속도에 대한 온도 민감도를 측정하였다.

• Computers and Concrete
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• 제32권5호
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• pp.439-454
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• 2023

In this article, the surface stress effects on the buckling analysis of the annular sandwich plate is developed. The proposed plate is composed of two face layers made of carbon nanotubes (CNT) reinforced composite with assuming of fully bonded to functionally graded porous core. The generalized rule of the mixture is employed to predict the mechanical properties of the microcomposite sandwich plate. The derived potentials energy based on higher order shear deformation theory (HSDT) and modified couple stress theory (MCST) is solved by employing the Ritz method. An exact analytical solution is presented to calculate the critical buckling loads of the annular sandwich plate. The predicted results are validated by carrying out the comparison studies for the buckling analysis of annular plates with those obtained by other analytical and finite element methods. The effects of various parameters such as material length scale parameter, core thickness to total thickness ratio (hc/h), surface elastic constants based on surface stress effect, various boundary condition and porosity distributions, size of the internal pores (e0), Skempton coefficient and elastic foundation on the critical buckling load have been studied. The results can be served as benchmark data for future works and also in the design of materials science, injunction high-pressure micropipe connections, nanotechnology, and smart systems.

• 한국분말재료학회지
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• 제31권1호
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• pp.23-29
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• 2024

This study investigates the effect of the microstructure of Li_1.3Al_0.3Ti_1.7(PO₄)₃ (LATP), a solid electrolyte, on its ionic conductivity. Solid electrolytes, a key component in electrochemical energy storage devices such as batteries, differ from traditional liquid electrolytes by utilizing solid-state ionic conductors. LATP, characterized by its NASICON structure, facilitates rapid lithium-ion movement and exhibits relatively high ionic conductivity, chemical stability, and good electrochemical compatibility. In this study, the microstructure and ionic conductivity of LATP specimens sintered at 850, 900, and 950℃ for various sintering times are analyzed. The results indicate that the changes in the microstructure due to sintering temperature and time significantly affect ionic conductivity. Notably, the specimens sintered at 900℃ for 30 min exhibit high ionic conductivity. This study presents a method to optimize the ionic conductivity of LATP. Additionally, it underscores the need for a deeper understanding of the Li-ion diffusion mechanism and quantitative microstructure analysis.

• 한국축산식품학회지
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• 제44권4호
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• pp.934-950
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• 2024

This study addresses the prevalent issue of meat species authentication and adulteration through a chemometrics-based approach, crucial for upholding public health and ensuring a fair marketplace. Volatile compounds were extracted and analyzed using headspace-solid-phase-microextraction-gas chromatography-mass spectrometry. Adulterated meat samples were effectively identified through principal component analysis (PCA) and partial least square-discriminant analysis (PLS-DA). Through variable importance in projection scores and a Random Forest test, 11 key compounds, including nonanal, octanal, hexadecanal, benzaldehyde, 1-octanol, hexanoic acid, heptanoic acid, octanoic acid, and 2-acetylpyrrole for beef, and hexanal and 1-octen-3-ol for pork, were robustly identified as biomarkers. These compounds exhibited a discernible trend in adulterated samples based on adulteration ratios, evident in a heatmap. Notably, lipid degradation compounds strongly influenced meat discrimination. PCA and PLS-DA yielded significant sample separation, with the first two components capturing 80% and 72.1% of total variance, respectively. This technique could be a reliable method for detecting meat adulteration in cooked meat.

• Journal of Nutrition and Health
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• 제21권2호
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• pp.129-133
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• 1988

수유기간의 경과에 따른 모유중의 비중, 총고형분, 단백질 함량 변화를 살펴 보고자 수유부 27명을 대상으로 분만후 15일부터 150일까지 추적하여 채취한 총112개 모유시료로 부터 얻은 결과는 다음과 같다. 즉 모유 비중의 경시적인 변화는 15일경에 1.0298(S.D. 0.0044, n=25), 30일경에 1.0304(S.D. 0.0046, n=24), 60일경에 1.0270(S.D. 0.0035, n=20) 90일경에 1.0293(S.D. 0.0055, n=18), 120일경에 1.0254(S.D. 0.0038, n=16), 150일경에 1.0268(S.D. 0.0039, n=9)로서 나타났고 수유기간이 경과함에 따라 유의하게 감소하는 경향을 보였다. 총고형분은 모유 100$m\ell$중에 15일 경에 12.48g(S.D. 1.23, n=25), 30일경에 12.31g(S.D. 1.31, n=24) 60일경에 12.47g (S.D. 1.45, n=20), 90일경에 11.81g (S.D. 1.85, n=18), 120일경에 11.44g(S.D. 0.92, n=16) 150일경에 11.88 (S.D. 0.89, n=9)으로 나타났고 수유기간의 경과에 따른 유의한 차이는 보이지 않았다. 모유 100$m\ell$중 단백질함량은 1.07~1.46g의 범위였고, 수유기간별 변화는 15일경에 1.46g (S.D. 0.20, n=25), 30일 경에 1.32g (S.D. 0.19, n=24) 60일경에 1.15g (S.D. 0.10, n=20), 90일경에 1.09g (S.D. 0.17, n=18), 120일경에 1.11g (S.D. 0.17, n=16), 150일 경에 1.07g (S.D. 0.18, n=9)으로 수유기간이 경과 함에 따라 유의하게 감소하는 경향을 보였다. 또한 수유기간 15, 30, 50, 90, 120, 150일에 수집한 모유시료 전체의 총평균 단백질함량은 1.20g (S.D. 0.14, n=27, 총시료수 112)로 나타났다.

• 산업식품공학
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• 제13권2호
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• pp.159-163
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• 2009

팽화미분을 활용한 타락죽의 제품화를 위한 기초자료를 제공하기 위해서 팽화미분 첨가에 따른 타락죽의 pH, 수분, 고형분, 총당, 아밀로스, 점도, 퍼짐성 그리고 색도 변화를 조사하였다. 타락죽의 pH는 갈은 쌀로 제조한 시료가 팽화미분으로 제조한 시료보다 높았다. 그리고 분유를 첨가한 시료도 우유를 첨가한 시료보다 높았다(p<0.05). 수분 함량은 갈은 쌀과 분유를 혼합한 타락죽이 84.56%로 가장 높았고, 팽화미분과 우유를 혼합한 타락죽은 81.04%로 가장 낮았다(p<0.05). 고형분 함량은 수분함량과 반대되는 결과를 보였다(p<0.05). 총당 함량은 조리 시 가열처리한 시료사이에서 유의적인 차이가 없었고 가열처리하지 않은 시료보다 높았다(p<0.05). 팽화미분으로 제조한 타락죽의 아밀 로스 함량이 갈은 쌀로 제조한 타락죽보다 높았다(p<0.05). 점도는 갈은 쌀 타락죽이 팽화미분 타락죽보다 높았으며 (p<0.05) 아밀로스 함량과 반비례하는 결과를 보였다. 퍼짐성은 점도와 상반되는 결과를 보였다(p<0.05). L값은 갈은쌀 타락죽이 팽화미분 타락죽보다 높았다. 적색도는 팽화미분 타락죽이 가장 높았으며(p<0.05), 갈은 쌀과 우유를 혼합한 시료가 가장 낮게 나타나 L값과 반대되는 결과를 보였다. 황색도는 a값과 유사한 경향을 보였다.

• 환경위생공학
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• 제14권1호
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• pp.70-79
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• 1999

A questionary survey was conducted to investigate citizen's attitude to treatment facilities of municipal solid waste in Miryang during 8. June of 1998 and 22 June of 1988. Collection effiencies was 86.7%, as 260 individuals of the 300 individuals. The survey showed that 43.0% of answers recognized seriousness of problem of the waste treatment and 33.1% of respondents concerned about recycle of organic waste. 40.8% of total answers said that they most hated landfill site among waste treatment facilities, and most citizens wanted as much distant as possible from waste treatment facilities. It was investigated that the greater part of respondents wanted the greatest compensation. About 58% of respondents was opposed to complete waste treatment facilities. 36.2$ among answers wanted establishment of waste treatment facilities in an industrial complex or an industrial area. The majority of respondents was willing to increase recycle rate and recognized seriousness of landfill site security. The majority of citizens do not trust environmental administration of Miryang City and they think that democracy and open of administration need for overcome MINBY.

• 한국식품조리과학회지
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• 제18권4호
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• pp.426-432
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• 2002

The purpose of the study was to identify the standards of quality management in contract foodservice companies. The subject companies were selected by convenient sampling and surveyed for their standards. The questionnaire consisted of 7 categories: managements of food procurement, menu, production, personnel, equipment, information system, and solid waste. As a result of the study, 60% of the respondents appeared to use standard recipes, 51.5% of them spent 21-30% of the total cost as a labor cost, and 70% were reluctant to answer the food cost. The half of the respondents had job description and specification, 74.76% had training manuals on foodservice and computer software program, and 80.6% had a training program for solid waste management.