• 한국연초학회지
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• 제10권1호
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• pp.75-82
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• 1988

Cigarettes were made using a triple filter with several porous materials in its cavity. The removal effect of the adsorbents on carbon monoxide and hydrogen cyanide in cigarette smoke was investigated with the variation of their surface area and pore volume distributions. Several attempts were made to activated coconut shell based char under the fixed steam purging rate. 1. The specific surface area increased in number of micropore. It was found for transitional pore to have a little effect on the total surface area. 2. A Small amount of the particulate matter adsorbed on the adsorbents with transitional pores, Zeolite showed a little effect on the carbon monoxide adsorption though its small pore volume, but there was no significant difference in the adsorption capacity zeolite and the others. 3. In the adsorption for hydrogen cyanide as a vapor phase in cigarette smoke, the adsorption effect of the adsorbents increased remarkably with increasing their surface area and number of micropore. It was considered that the adsorbents with small pore volume like molecular seive 4A, in which the capillary diffusion of adsorbates could not be able, would not be effective for the adsorption of hydrogen cyanide.

• 펄프종이기술
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• 제42권3호
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• pp.67-73
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• 2010

Pine (Pinus densiflora) and aspen (Populus euramericana) wood meals were treated with ozone at various time schedule in acidic condition. The lignin contents and surface area of the ozone treated wood meals were determined and the enzymatic hydrolysis rate of ozonated wood meals was evaluated. The feasibility of enzymatic hydrolysis of the ozone treated wood meal was obviously influenced with the degree of delignification. After ozone treatment of wood meal for 10min, total pore volume were slightly increased in the surface of wood meal. When wood meals were treated with ozone longer than 10min, few change in the pore volume was observed. However, the area of over $50{\AA}$ of pore size is increased with ozonation time. As a conclusion, the rate of enzymatic hydrolysis of wood is more effective with the pore size distribution than the total pore volume.

• 한국분말재료학회지
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• 제10권2호
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• pp.97-102
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• 2003

The powder-in sheath rolling was applied to the fabrication of $Al/Al_2O_3$ composite. A stainless steel tube with outer diameter of 12 mm and wall thickness of 1 mm was used as a sheath. Mixture of aluminum powder and $Al/Al_2O_3$ particles of which volume content was varied from 5 to 20 vol.% was filled in the tube by tap filling and then rolled to 75% reduction at ambient temperature. The re]]ed specimen was sintered at 56$0^{\circ}C$ for 0.5 hr. The $Al/Al_2O_3$ composite fabricated by the sheath rolling and subsequent sintering showed the relative density higher than 0.96. The tensile strength of the composite increased with the volume content of $Al_2O_3$ particles, and it reached a maximum of 90 MPa which is 1.5 times higher than unreinforced material. The elongation decreased with the volume content of $Al_2O_3$ particles. It is concluded that the powder-in sheath rolling is an effective method for fabrication of $Al/Al_2O_3$ composite.

• 방사성폐기물학회지
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• 제15권2호
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• pp.181-189
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• 2017

방사성금속폐기물의 관리 옵션들을 안전성, 경제성, 작업자 피폭, 부피 감용 등의 선별 기준을 적용하여 비교 평가하였다. 원전 해체로부터 발생하는 금속폐기물의 관리 옵션에는 무구속 방출, 제한적 재사용, 그리고 직접 처분이 있다. 고려된 각각의 옵션들은 금속폐기물의 절단과 용융에 의한 부피감용을 수반한다. AHP기법을 적용하여 각 옵션들의 순위를 부여하였다. 방사성금속폐기물을 용융하여 금속 잉곳을 제조한 후 제한적 재이용 또는 무구속 방출하는 방안이 가장 효율적인 옵션으로 도출되었다.

• Structural Engineering and Mechanics
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• 제67권6호
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• pp.659-669
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• 2018

The Dynamic equations in the polar coordinates are drawn out using the MLPG method for the non-symmetric FG cylindrical shell. To simulate the mechanical properties of FGM, the nonlinear volume fractions for radial direction are used. The shape function applied in this paper is a form of the radial basis functions, by using this function all the requirements for an effective and suitable shape function are established. Hence in this study, the multiquadrics (MQ) radial basis functions are exploited as the shape function governing the problem. The MLPG method is combined with the the Newmark time approximation scheme to solve dynamic equations in the time domain. The obtained results by the MLPG method to be verified are compared with the analytical solution and the FEM. The obtained results through the MLPG method show a good agreement in comparison to other results and the MLPG method has high accuracy for dynamic analysis of the non-symmetric FG cylindrical shell. To demonstrate the capability of the present method to dynamic analysis of the non-symmetric FG cylindrical shell, it is analyzed dynamically with different volume fraction exponents under harmonic and rectangular shock loading. The present method shows high accuracy, efficiency and capability to dynamic analysis of the non-symmetric FG cylindrical shell with nonlinear grading patterns.

• 한국컴퓨터산업학회논문지
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• 제2권3호
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• pp.377-388
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• 2001

소프트웨어 척도는 소프트웨어를 특징화하기 위한 효율적인 방법을 제공한다. 척도들은 전통적으로 식의 정의를 통해 구성되었지만 이러한 접근은 소프트웨어를 특징화해주는 모든 매개변수사이의 모든 관계를 완전하게 이해할 수 있을 때만 적용 가능하다는 한계가 있다. 이 논문은 비선형 함수를 매우 정교하게 근사화 시키고, 인지 심리 이론을 결합할 수 있는 퍼지 논리 시스템을 사용하였다. 우선, Java 프로그램으로부터 수집된 12개 척도들의 인자들로부터 다중 회귀식을 추출하였다. 또한 그 중에서 프로그램 볼륨 인자에 인지 심리 이론을 적용하고 퍼지 학습을 수행하여 프로그램 볼륨 복잡도를 측정하였다. 이 연구는 소프트웨어 척도의 분석과 설계의 더 나은 조사를 위한 토대가 될 수 있을 것이다.

• 한국조리학회지
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• 제9권2호
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• pp.1-10
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• 2003

느릅나무 추출액을 0, 10, 20, 30% 첨가한 식빵을 제조한 결과, 추출액의 첨가량이 많을 수 록 반죽수율은 다소 증가하였으며, 식빵의 부피도 약간 증가한 것으로 나타났다. 빵의 기계적 특성을 조사한 결과 경도(hardness)의 경우 느릅나무 추출액 30%에서 가장 높았으며, 탄력성(springiness)의 경우 20% 첨가군에서 가장 높은 결과를 나타내었고, 점착성(gumminess)과 씹힘성(chewiness)은 느릅나무 추출액 함량이 높을 수 록 증가하였다. 색도의 경우 L 값은 대조군에 비해서 느릅나무 추출액 농도가 높을 수 록 낮은 값을 나타냈었으며, a 값은 느릅나무 추출액 10%, 20% 첨가군에서 대조군에 비해 약간 증가되었고, b 값은 모든 첨가군에서 뚜렷한 차이가 없었다. 관능검사에서는 느릅나무 추출액 10% 첨가군에서 가장 좋은 기호도를 보였으나, 반죽수율이나, 물성 특성에 미치는 영향과 느릅나무 추출액의 기능성 성분을 고려할 때 20% 첨가군이 적합한 것으로 판단된다.

• 대한토목학회논문집
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• 제13권5호
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• pp.255-260
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• 1993

본 연구에서는 실트흙의 거동을 자동화된 삼축시험기를 사용하여 비배수 상태하에서 정적 삼축압축과 인장시험을 수행하여 파괴전과 파괴상태시 체적변형 경향으로 인한 응력 변형률 상태를 점토질흙과 비교 검토하였다. 점토질흙의 거동과 비교하기 위하여 순수 실트인 실리카 분말을 사용하여 성형된 시료를 450 kPa인 유효구속 압력까지 등방압밀시킨 후 압밀하중을 감소시키며 과압밀비(OCR)가 다른 시료를 만들어 전단시험을 하였다. 해석 결과 정규압밀 실트의 비배수 강도는 점토와 달리 전단하에서 체적팽창으로 계속 증가하며 과압밀 실트(OCR>2)에 있어서도 체적변형 경향으로 상당히 다른 거동을 보임을 알 수 있었다.

• Structural Engineering and Mechanics
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• 제52권4호
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• pp.663-686
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• 2014

This paper deals with free vibration analysis of bidirectional functionally graded annular plates resting on a two-parameter elastic foundation. The formulations are based on the three-dimensional elasticity theory. This study presents a novel 2-D six-parameter power-law distribution for ceramic volume fraction of 2-D functionally graded materials that gives designers a powerful tool for flexible designing of structures under multi-functional requirements. Various material profiles along the thickness and in the in-plane directions are illustrated by using the 2-D power-law distribution. The effective material properties at a point are determined in terms of the local volume fractions and the material properties by the Mori-Tanaka scheme. The 2-D differential quadrature method as an efficient and accurate numerical tool is used to discretize the governing equations and to implement the boundary conditions. The fast rate of convergence of the method is shown and the results are compared against existing results in literature. Some new results for natural frequencies of the plates are prepared, which include the effects of elastic coefficients of foundation, boundary conditions, material and geometrical parameters. The interesting results indicate that a graded ceramic volume fraction in two directions has a higher capability to reduce the natural frequency than conventional 1-D functionally graded materials.

• The Korean Journal of Pain
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• 제8권1호
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• pp.60-64
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• 1995

Stellate ganglion block is a selective sympathetic blockade affecting the head and neck, and the upper extemity. It is an important method which has been used most frequently in neuro-pain clinic due to its wide range of indications. The authors attermpted to define the minimal volume of local anesthetic which need for successful stellate ganglion block by using 1% mepivacaine HCl mixed with dye. In 40 heathy volunteers, two different volumes, 3 ml in the group 1 (n=20) and 4 ml in the group 2 (n=20), were injected by an anterior paratracheal technique at the sixth cervical vertebral level. We compared the degree in sympathetic blockade by clinical sings and symptoms and also checked the spread range of dye by plain X-ray. With seven criteria for an effective block. mean score was 5.7 in group 2, while 3.4 in group 1. These results suggest that 4 ml of local anesthetic are adequate for a successful stellate ganglion block.