• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.499-504
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• 2004

The purpose of this study is to investigate a investigating of a floor-impact isolation system using damping materials in apartment buildings. The stiffness elastic modulus(k) by puls impact forces were calculated loss factor by Hilbert transforms. It is absolved that natural frequency was moved floor shock-absorbing materials and the impact force was reduced by floor panel. The slab was constructed by damping materials. As towards a result, the system showed inverse A 45dB by heavy weight-impact noise and inverse A 52dB by light-impact noise. High frequencies impact-noise can be reduced by upgrading naturial frequency of vibration and noise in the system.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.368-372
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• 2003

There arc two methods to evaluate the combustion product, that is analysis method and measurement method. Properties of the combustion products, constituents, and quanties, can be used to calculate boiler efficiency and beat losses. Using combustion evaluation methods combustion calculation were performed at certain condition and analyze the results. In this paper by comparing the results between two methods, deviation, correction and possibility of site application were confirmed

• Bulletin of the Korean Institute for Industrial Safety
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• v.3 no.1
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• pp.1-5
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• 2003

작업관련 근골격계 질환은 최근 사업장의 집단적인 발병, 산업재해자수의 급증 등으로 인하여 주된 문제가 되고 있다. 특히, 자동차, 선박 등의 제조업에서 이러한 문제는 노사간의 갈등을 야기하는 주 요인으로 작용하여 사회적 이슈로 대두되었다. 이러한 산업재해 율 증가는 근골격계질환의 뇌심 혈관질환 등 작업관련성질환이 주도하고 있는 현상이다. 특히, 단순반복작업, 중량물 취급작업, 부적절한 작업자세 등에 의하여 신체에 과도한 부담을 주었을 때 나타나는 요통, 경견완장해 등 근골격계 질환은 매년 급증하고 있으며 향후에도 지속적인 증가가 예상된다. 이로 인하여 생산성 저하, 근로의욕저하, 품질저하 등으로 경영손실은 물론 직접 의료비의 부담이 커지고 있는 실정이다. 이와 동시에 근골격계 질환에 대한 직원들의 보상과 작업조건 개선에 대한 요구는 점차 증가하고 있고, 가장 중요한 노$.$사간의 쟁점사항으로 부각되고 있다. 정부에서는 근골격계 질환 예방대책으로 '근골격계 부담 작업으고 인한 건강장해예방' 편을 입법화를 하였으며 근골격계 예방팀을 구성하여 대책 마련에 고심 중에 있다.(중략)

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.936-941
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• 2005

Apartment building floor with a damping layer can be modeled as a sandwich plate. In order to reduce low frequency noise more efficiently due to heavy impact on such a floor, thickness of the damping layer needs to be optimized at the design stage. Modal loss factors are determined in this paper by RKU equation which is popular In sandwich plate theories. Optimum damping layer thickness determined at each mode is weighted so that several modes in the frequency range of interest can be included in a more systematic way. Furthermore, to reflect frequency-dependent characteristics of complex stiffness of the damping layer, an iteration method is proposed in finding modal frequencies.

• Journal of the Korean Society of Food Science and Nutrition
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• v.11 no.3
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• pp.57-62
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• 1982

This study was conducted to investigate the changes in plant state, chlorophyll, free amino acids and vitamin C content of soybean sprouts during circulation periods. The experiment was carried out under the indoor natural light and complete darkness at $20^{\circ}C$. The results are summarized as follows; Soybean sprout was grown about one cm in the darkness for 7 or 24 hours, but under the indoor natural light it was not grown. Weight was decreased both in the darkness and under the light. In the darkness the color of sprouts were not changed, but under the light the color was changed in 7 or 24 hours. Chlorophyll contents was increased rapidly by light in the cotyledon. Chlorophyll formation brought about loss not only in amino acids but also porphyrins, but it did not in the amino acids of hypocotyl. The kinds of amino acids being brought about loss under the light were cystine, aspartic acid, serine, histidine and glycine. The 22$\sim$27% of vitamin C was lost in cotyledon by 7 hours exposured light and in hypocotyl after 5 hours.

• 한국방재학회:학술대회논문집
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• 2011.02a
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• pp.178-178
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• 2011

도로소음은 다양한 소음원에 의해 발생하며, 도로를 이용하는 사람과 도로 주변사람에게 큰 불편을 초래한다. 보다 쾌적한 환경을 원하는 현대인에게 있어 도로 소음의 경감은 중요한 환경 공해로 작용한다. 도로 소음을 줄이기 위해서는 여러 가지 방법이 있을 수 있으며, 이 중 도로 포장의 개선을 통해 도로 소음을 경감할 수 있으며, 이와 같은 포장을 저소음 포장이라고 한다. 저소음 포장은 주행하는 차량의 타이어와 노면이 마찰하면서 발생하는 소음을 최소화하기 위한 것으로 소음 발생의 메커니즘을 바탕으로 하고 있다. 저소음 포장중 가장 널리 사용되고 있는 방법은 공극을 늘리는 것이다. 약 20%의 공극은 타이어와 노면 사이의 에어펌핑음을 최소화 하며, 소리를 흡수하는 역할로 약 3dB의 소음 가소 효과가 있는 것으로 알려져 있다. 소음을 감소시키는 또 하나의 방법은 노면의 표면 조직을 매끈하게 하여 타이어와 노면의 충격음을 줄이는 방법이다. 노면의 평탄성을 개선하기 위해 포장에 사용되는 골재의 최대크기를 줄이는 소입경 포장을 소음 가소의 목적으로 유럽 등지에서 많이 사용되고 있다. 본 연구에서는 이와 같은 저소음 기능을 위해 공극률을 크게 하고 소입경 골재를 사용하는 소입경 저소음 포장의 현장 적용을 위한 배합 설계를 수행하였다. 소입경 저소음 포장의 최대 골재 크기는 현장 적용성과 경제성을 고려하여 10mm 골재를 사용하였으며, 수도권에서 입수한 4곳의 산지 골재를 분석하여 골재 합성 입도를 산정하였다. 10mm 저소음 포장의 골재 입도 범위는 공극률 15~18%를 목표로 하며, 이를 만족하기 위하여 배합 설계를 수행한 결과 5mm 통과 중량 백분율이 약 30%로 하는 개립도가 적당한 것으로 나타났다. 공극이 증가함에 따라 포장의 내구성 향상을 위해 사용된 고점도 바인더는 아스팔트 혼합물의 생산 및 시공온도를 증가시키게 된다. 또한 굵은골재의 비율이 높은 개립도 아스팔트 혼합물의 경우 운반과정과 포설 과정에서 온도가 빨리 떨어지는 단점이 있다. 이를 극복하기 위하여 중온 첨가제의 사용을 통해 생산 및 다짐온도를 낮추고자 하였다. 소입경 저소음 포장의 배합설계 과정은 배수성 포장의 배합설계 과정과 유사하나, 칸타브로 손실률과 흐름실험의 변곡점을 기준으로 할 경우, 칸타브로 손실률과 흐름 손실률이 매우 작아 변곡점을 판단하기 어렵기 때문에 칸타브로 손실률과 흐름 손실률의 기준 만족 여부로 판별하고, 최적 아스팔트 함량은 공극률을 기준으로 산정하는 것이 바람직할 것으로 판단된다. 중온 첨가제를 사용할 경우는 중온 첨가제로 인한 점도의 변화를 감안하여 혼합 및 다짐 온도를 결정하고 배합 설계를 수행하며, 중온 첨가제의 특성과 양에 따라 최적 아스팔트 함량이 변화하게 된다.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.10
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• pp.598-602
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• 2018

This study examined the characteristics of the waste catalyst used in the petroleum refinery operations. The total pore volume, specific surface area, and average pore size of the spent catalyst used in the petroleum refinery operations were 3.96cc/g, 13.81m2/g, and 1.15A, respectively. The weight loss observed in the range from $25^{\circ}C-700^{\circ}C$ for the spent catalysts using TG and DTA was approximately 23 wt. %. EDS analysis of the waste catalyst sample showed that the five major components were vanadium, nickel, manganese, iron, and copper. The extraction system is attractive for liquid-liquid extraction. In this study, Cynex 272 was used to extract vanadium from waste catalyst. The electrochemical characteristics of the extracted vanadium solution were measured by cyclic voltammetry (CV). As a result, an oxidation / reduction peak appeared, indicating the potential of an electrolytic solution.

• Korean Journal of Food Science and Technology
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• v.20 no.4
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• pp.536-540
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• 1988

Effects of blanching time, chemical dipping, freezing method and storage period on texture, color and yield of frozen whole and sliced mushrooms were investigated, and the results are summarized as follows; Frozen whole mushrooms blanched for 5min. had markedly tougher texture than mushrooms blanched for 1 or 2 minutes. As the storage time of frozen mushrooms increased from 3 to 6 months, shear press values increased very significantly. The texture of Freon frozen and plate frozen mushrooms was similar after 3 months storage. Blanching time did not affect texture of frozen sliced mushrooms significantly, but storage time did. The results of sensory evaluation for texture were in good agreement with shear press values. Chemical dipping methods were effective in maintaining desirable color of frozen whole and sliced mushrooms stored for 3 months. The yield of frozen whole mushrooms was significantly increased by shortening blanching time in combination with chemical dipping. Sliced mushrooms required at least 2 min. blanching, to avoid excessive breakage in mechanical slicing operation, for better yield.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.35 no.4
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• pp.363-368
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• 2007

Lithium-ion batteries providing high gravimetric energy density are rapidly replacing Ni-Cd and Ni-H2 in aerospace applications. The main advantage is the weight reduction of the battery system. Weight is a major concern in aerospace applications. Also, lithium-ion offer low thermal dissipation, high energy efficiency, and low cell cost. The Onboard battery module for KSLV-I(Korea Space Launch Vehicle) contains 80 Sony US18650 cells configured as 10 strings in parallel, with each string containing 8 series connected cells. This allows to meet voltage and capacity requirements specified for the mission. In this paper design description and specifications of lithium-ion battery developed are presented. Qualification test flow is also shown to make sure the performance in the predicted space environment. Electrical performance was simulated by dedicated program, and verified with electronic load. Lastly, the capacity was proven on real equipment load assembly.

• The Korean Journal of Food And Nutrition
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• v.7 no.4
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• pp.297-306
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• 1994

This experiment was carried out to investigate the healing loss and the heavy metal residues such as copper, zinc, manganese, cadmium and lead In porcine visceras by inductively coupled argon plasma spectrometer(ICP), and to probe changes when porcine visceras were boiling In water treatment(BWT), heating in autoclave treatment (HAT) and heating In oil treatment (HOT) . The range of heating loss on porcine viscera were BWT(23.11∼34.53%) , HAT(18.48∼28.00%) and HOT(14.20∼25.22%)and the heart tissue were higher and liver were lower than those of the other tissues. The total value of heavy metal residues in large intestine, small intestine, heart, kidney, liver and stomach tissue were 11.298${\pm}$5.302 ppm, 27.825${\pm}$8. 177 ppm, 16.756${\pm}$6.334 ppm 21.107${\pm}$6.057 ppm, 25.369 ${\pm}$ 10.164 ppm and 12.611 ${\pm}$5.513 ppm, respectively. Heavy metal residues in porcine visceras tended to decrease according to heating methods and the variety viscera, and the change of total heavy metal residues on BWT, HAT and HOT were 4.16∼32.57%, 12.01∼28.09% and 9.60∼25.76%, respectively. The decrease of lead element of mean value were 21.76% and copper, zinc, manganese and cadmium element were 18.00∼ 18.16%. The change of heavy metal residues were not significant in the porcine visceras(P>0.05), and the these were significantly correlated among the three heating method(P < 0.05).