• 대한기계학회논문집A
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• 제24권2호
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• pp.472-480
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• 2000

A macroscopic yield criterion for porous solids with pressure-sensitive matrices modeled by Coulomb's yield criterion was obtained by generalizing Gurson's yield criterion with consideration of the hydrostatic yield stresses for a spherical thick-walled shell and by fitting the finite element results of a voided cube. The macroscopic yield criterion is valid for negative mean normal stresses as well as for positive mean normal stresses. From the yield criterion, a plastic potential function for the porous solids was derived either for plastic normality flow or for plastic non-normality flow of pressure- sensitive matrices. In addition, the elastic relation, an evolution equation of the plastic flow stress of the matrices and an evolution equation of the void volume fraction were presented to complete a set of constitutive relations. The set of constitutive relations was implemented into a finite element code ABAQUS to analyze the material behavior of rubber-toughened epoxies. The cavitation and the deformation behavior were analyzed around a crack tip under three-point bending and around notch tips under four-point bending. In the numerical analyses, the cavitation of rubber particles was considered via a stress-controlled nucleation model. The numerical results indicate that a reasonable cavitation zone can be obtained with void nucleation controlled by the macroscopic mean normal stress, and a plastic zone is smaller around a notch tip under compression than under tension. These numerical results agree well with corresponding experimental results on the cavitation and plastic zones.

• Asian-Australasian Journal of Animal Sciences
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• 제14권1호
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• pp.92-95
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• 2001

The Baghabarighat Milk Shed Area (BMSA), in Bangladesh belonging to the Bangladesh Milk Producers Cooperative Union Limited (BMPCUL) was selected to study the qualitative and quantitative aspects of dairy milk and to establish a trend throughout the year (July 1995 to June 1990) of milk collected at morning and evening, and daily. The average fat, solids-not-fat (SNF) and total solid (TS) contents of the morning milk were 4.58, 7.75 and 12.33%, respectively, and evening milk contained 5.41, 7.81 and 13.23%. The values for the quality varied (p<0.01) throughout the year without a specific trend. Higher milk collection occured at morning (52.77%) than evening (47.24%), but total yield of fat from morning milk was lower (48.74%) than evening milk (51.26%) due to a lower fat value (4.58%). Yield of SNF (52.57% morning, 47.37% evening) followed the values of the amount of milk collected due to their similar value at morning (7.75) and evening (7.81). Overall, TS yield was 51 and 49% from morning and evening. There was not a significant (p>0.01) relationship between fat and TS values of morning milk with those of evening milk, but there was a correlation (p<0.01) between milk yield at morning and all other parameters for evening. Solids-not-fat value of morning milk was related with yield and SNF value of milk from evening, but not with fat and TS evening milk. It may be concluded that evening milk contains higher amounts of fat, SNF and TS, but yields were higher at morning, except fat. Milk collected at morning showed a relationship with all the parameters found at evening.

• Biotechnology and Bioprocess Engineering:BBE
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• 제8권2호
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• pp.117-125
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• 2003

Experimental and theoretical works were performed for the separation of large polyelectrolyte, such as DNA, in a column packed with gel particles under the influence of an electric field. Since DNA quickly orient in the field direction through the pores, this paper presents how intraparticle convection affects the residence time distribution of DNAs in the column. The concept is further illustrated with examples from solid -liquid systems, for example, from chromatography Showing how the column efficiency is improved by the use of a n electric field. Dimensionless transient mass balance equations were derived, taking into consideration both diffusion and electrophoretic convection. The separation criteria are theoretically studied using two different Peclet numbers in the fluid and solid phases. These criteria were experimentally verified using two different DNAs via electrophoretic mobility measurements. which showed how the separation position of the DNAs varies in the column in relation to the Peg/Pef values of an individual DNA. The residence time distribution was solved by an operator theory and the characteristic method to yield the column response.

• 센서학회지
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• 제17권4호
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• pp.273-280
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• 2008

Monolith aperture-type oxygen sensors with simple structure of YSZ(pin-hole)/Pt/ YSZ(solid electrolyte)/Pt were fabricated by co-firing technique. To enhance the yield of productivity, a couple of YSZ green sheets for diffused barrier and solid electrolyte were prepared by tape-casting and co-firing method. The limit current characteristics of the oxygen sensors were measured between 500 and $650^{\circ}C$ The heating temperature of $600^{\circ}C$ was optimum as a portable oxygen sensor in the range of oxygen concentration from 0 to 75 vol%. Linear proficiency of limit current behavior as a function of oxygen concentration was controlled by the variation of aperture dimension. The fabricated oxygen sensors showed the stable sensing output for 30 days. Gas leakage in bonding area due to warping, cracking and thermal cycling was not found in the period.

• 한국식품저장유통학회지
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• 제7권2호
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• pp.171-176
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• 2000

Drink and tea-bag were processed with safflower seed powder. Drinks were processed with 90$^{\circ}$C hot water extraction. Yield, soluble solid, pH and centrifugation residue of drinks were ranged in 79.2~89.3%, 0.6~0.99%, 5.98~6.40 and 1.00~1.18, respectively. Sensory score of overall acceptance in drinks were highest at that of enzyme treated drink. Tea-bag was processed with roasted safflower seed powder, alone(1.2g) and the mixtured tea-bags were consisted of persimmon leaves, pine needle and angelica gigas powder in same amount, respectively. Teas were prepared with extraction at 80$^{\circ}$C water for 2 min. Soluble solid and sensory evaluation score of teas were the highest when the tea was processed with safflower seed alone.

• 자연과학논문집
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• 제8권2호
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• pp.129-136
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• 1996

염화물을 이산화질소기체로 반응시킬때와 같이 고체 염화칼륨으로부터 고체 질산칼륨으로의 직접적인 전환이 질산칼륨의 생성을 암시하고 있음을 확인하였다. 또 열역학적 추정에 있어서 자유에너지 변화는 상온에서 유리하며 발열반응을 보여준다. 그리고 높은 수율과 함께 적은양의 물존재로 인하여 상온에서 반응이 일어나며 반응생성물에서 염화니트로실이 동시에 생성되고 있다.

• BMB Reports
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• 제37권4호
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• pp.387-393
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• 2004

The L-asparaginase (E. C. 3. 5. 1. 1) enzyme was purified to homogeneity from Pseudomonas aeruginosa 50071 cells that were grown on solid-state fermentation. Different purification steps (including ammonium sulfate fractionation followed by separation on Sephadex G-100 gel filtration and CM-Sephadex C50) were applied to the crude culture filtrate to obtain a pure enzyme preparation. The enzyme was purified 106-fold and showed a final specific activity of 1900 IU/mg with a 43% yield. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) of the purified enzyme revealed it was one peptide chain with $M_r$ of 160 kDa. A Lineweaver-Burk analysis showed a $K_m$ value of 0.147 mM and $V_{max}$ of 35.7 IU. The enzyme showed maximum activity at pH 9 when incubated at $37^{\circ}C$ for 30 min. The amino acid composition of the purified enzyme was also determined.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.333-338
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• 1997

A hollow crankshaft is considered as part of an effort to reduce the weight of the automobile powertrain. Since the resulting mass reduction alters both the inertia and stiffness properties of the crankshaft, the vibration characteristics of the hollow crankshaft needs to be investigated in comparison with the original solid crankshaft. The crankshafts are modeled by 38 lumped mass and stiffness elements, in which the dynamic parameters for each lumped element are obtained by the finite element calculation. The fluid-film bearings supporting the crankshaft give rise to linear spring and damping elements that can be derived from the hydrodynamic bearing model. The transfer matrix method is applied to yield the natural frequencies and mode shapes of the crankshaft vibration. The natural frequencies of the hollow crankshaft are founded to be greater than that of the solid crankshaft, and the incorporation of the bearing stiffness tends to accentuate the difference.

• 대한약학회:학술대회논문집
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• 대한약학회 2003년도 Proceedings of the Convention of the Pharmaceutical Society of Korea Vol.2-1
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• pp.89-89
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• 2003

Numerous lead compounds, based on multipurpose privileged structures, can be generated that address a variety of targets from a gene family of interest, irrespective of therapeutic area. Solid-phase organic synthesis has been emerged as a powerful technique in generating combinatorial libraries of small organic molecules useful for drug discovery. Heterocyclic compounds provide scaffolds on which pharmacophores can be arranged to yield potent and selective drugs and a variety of heterocycles have been synthesized on solid support. (omitted)

• 한국균학회지
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• 제49권4호
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• pp.525-530
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• 2021

The cultivation in sawdust media, mushroom productivity, and fruiting body characteristics of Lentinula edodes strains NIFoS 2778 and NIFoS 3363 were compared according to the inoculation conditions. The cultivation period was 5% shorter when liquid spawn was used. Fruiting bodies were induced after 113 days of incubation on media inoculated with liquid spawn, and the cultivation period was 119 days on media inoculated with solid spawn. Mushroom productivity of NIFoS 2778 was the highest (661.4 g) when 36 mL of liquid spawn was used. For NIFoS 3363, mushroom production was higher under liquid inoculation conditions when the same amount of liquid and solid spawns were used. The mushroom characteristics of the two strains were not significantly different, except for gill width and stipe diameter.