• 한국지반환경공학회 논문집
• /
• 제2권3호
• /
• pp.81-88
• /
• 2001

다공질 매체의 거동은 선형 열역학적 다공 탄성 거동, 선형 다공 점성-탄성 거동, 다공소성 거동, 그리고 다공 점성-소성 거동 등으로 모형화가 된다. 또한 시간에 따라 그 거동 양상이 복합적인 형태를 띈다. 다공질 매체는 간극 속의 구성물들이 서로 상대속도를 가지며 상호 작용을 하기 때문에 coupling 효과를 고려한 다공질 매체의 변형 거동에 대한 구성모델의 개발이 필수적이다. 본 논문에서는 균질하고 등방성을 가진 재료들로 이루어진 다공질 매체의 3차원적인 거동을 포화도에 따라 완전 포화시와 부분 포화시로 나누어 연속체 다공 역학의 뼈대 위에 지배방정식들을 구한다. 또한 다공질 매체의 거동을 이해하고 해석할 수 있는 구성모델을 개발할 수 있는 토대를 마련한다. 본 연구가 확장될 경우 다공질 매체의 정확한 거동 해석과 변형량 예측이 이루어질 수 있을 것이다. 특히 도시 고형화 폐기물 매립지반의 3차원적인 거동을 해석할 수 있는 기초가 마련되어 비균질하고 이방성을 가진 재료들로 이루어진 다공질 매체 지반의 활용이 활발하게 이루어 질 것으로 기대된다.

• 한국수산과학회지
• /
• 제27권6호
• /
• pp.839-846
• /
• 1994

Changing concepts in fishery science increasingly are recognizing depletion of traditional stocks, utilization of alternate(non-traditional) species, demand for high quality products, and a total resource utilization approach. Innovative practices are occurring in fisheries processing wherein solid and liquid discharges are no longer treated as 'waste,' but rather as valuable feedstocks for recovery of a variety of value-added ('value enhanced') by-products. Among these are protein hydrolysates, soluble proteins and amino acids, proteolytic enzymes, flavor and flavor extracts, pigments, and biopolymers such as chitosan. Properties and applications of this deacetylated derivative of chitin are noted. Crustacean processing by-products are discussed in terms of their serving as materials for generation of natural flavors and flavor extracts, and products such as fish sauces using contemporary enzymatic techniques. Various food and feed applications of fisheries processing by-products are illustrated with increased usage seen in formulated diets for an expanding aquaculture market. Examples are given of aquaculture becoming increasingly significant in global fisheries resource projections. Critical issues in the international seafood industry Include those of seafood quality, processing quality assurance (HACCP), and recognition of the nutritional and health-related properties of fisheries products. A variety of current seafood processing research is discussed, including that of alternate fish species for surimi manufacture and formulation of value-added seafood products from crawfish and blue crab processing operations. Increasing emphasis is being placed on international aspects of global fisheries and the role of aquaculture in such considerations. Coupled with the need for the aquatic food industry to develop innovative seafood products for the 21st century is that of total resource utilization. Contemporary approaches in seafood processing recognize the need to discard the traditional concept of processing 'waste' and adapt a more realistic, and economically sound, approach of usable by-products for food and feed application. For example, in a period of declining natural fishery resources it is no longer feasible to discard fish frames following fillet removal when a significant amount of residual valuable flesh is present that can be readily recovered and properly utilized in a variety of mince-based formulated seafood products.

• 환경생물
• /
• 제21권1호
• /
• pp.31-35
• /
• 2003

유자의 착즙방법별 품질특성과 관능검사특성을 알아보기 위하여 원심분리식과 압착식 및 효소처리하여 압착한 방법으로 나뉘었다. 수율을 높이기 위하여 펙틴분해효소를 첨가한 방법이 수율이 68%로 가장 높고 압착식이 26.3%로 낮게 나타났다. PH는 큰 차이가 없었으나 당도는 압착한 방법이 6.0$^{\circ}$brix로 가장 높았고, 원심분리식이 4.5$^{\circ}$brix로 가장 낮았으며, 유리당은 모든 추출방법에서 fructose가 높은 함량을 보였다. 전체적인 유리당은 압착식이 높게 나타났다. 유자의 전처리에 따라 착즙액의 특성은 현저하게 달라지므로 유자의 전처리에 따라 음료제조시 당과 산 첨가량을 달리할 필요가 있을것으로 보인다. 원심분리식은 산이 강하고 당이 적으면 수율이 작고, 100 mesh체에 거른 추출 방법식은 수율은 너무 작고 작업의 용이성 면에서도 부적당하고 당도도 비교적 높고 수율이 높은 펙틴분해효소로 처리한 방법이 보다 적당한 가공방법으로 생각되었다.

• Journal of Pharmaceutical Investigation
• /
• 제35권6호
• /
• pp.453-460
• /
• 2005

4-Aminopyridine (AP) is a potassium channel blocker used in the treatment of neurological disorders such as multiple sclerosis and Alzheimer disease. AP‘s window of therapeutic effect appears to correlate with its plasma halflife (3.5 hours). It demonstrates pH-dependent solubility because of a weakly basic drug. In addition, the resulting release from conventional matrix tablets decreases with increasing pH-milieu of the gastrointestinal tract. The aim of this study is to design sustained release matrix tablet containing AP, overcoming this problem. $Eudragit^{\circledR}$ L 100 (EuL) and sodium alginate were used in an effort to achieve pH independent drug release. The effect of sodium alginate and EuL on drug release from matrix tablet was investigated. The drug release behavior from the different tablets was analyzed by $t_{20%},\;t_{40%},\;t_{60%}$, The exponential diffusion coefficient n, kinetic constant K were calculated according to the Korsmeyer-Peppas equation. The drug release from matrix tablets prepared with sodium alginate was decreased with increasing the content of sodium alginate in pH 7.4 while there is no significant difference in pH 1.2. The exponent n values were determined to be approximately 0.5 and 0.8 respectively, in both pH 1.2 and 7.4. These values indicate diffusion-based anomalous mechanism and erosion-based anomalous mechanism, respectively. The drug release from sodium alginate matrix tablets prepared with solid dispersion of EuL containing drug showed a slow drug release in an acidic medium and a more fast drug release in phosphate medium, compared with sodium alginate matrix tablets prepared with physical mixture. These results may be attributed to the gel forming ability of sodium alginate and pH dependent solubility of EuL. Therefore, sustained-release AP matrix tablets using sodium alginate and EuL were successfully prepared.

• 기술사
• /
• 제17권3호
• /
• pp.22-31
• /
• 1984

Sardine ant mackerel so called dark muscled fish have been underutilized due to the disadvantages in bloody meat color, high content of fat, and postmortem instability of protein. Recent efforts were made to overcome these defects and develope new types of product such as texturized protein concentrates and dark muscle eliminated minced fish. Approach of this study is based on the rapicl dehydration of foamed fish-starch paste by dielectric heating. In process comminuted sardine meat was washed more than three times by soaking and decanting in chilled water and finally centrifuged. The meat was ground in a stone mortar added with adequate amounts of salt, foaming agent, and other ingredients for aid to elasticity and foam stability. The ground meat paste was extruded in finger shape and heated in a microwave oven to give foamed, expanded, and porous solid structure by dehydration. Dielectric constant ($\varepsilon$′) and dielectric loss ($\varepsilon$") vcalues of sardine meat paste were influenced by wavelength and moisture level. Those values at 100KHz and 15MHz were ranged 2.25∼9.86 ; 2.22∼4.18 for $\varepsilon$′ and 0.24∼19.24 ; 0.16∼1.25 for $\varepsilon$", respectively, at the moisture levels of 4.2∼13.8％. For a formula for fish-starch paste preparation, addition of 20∼30% starch (potato starch) to the weight of fish meat, 2∼4% salt, and 5∼10% soybean protein was adequate to yield 4∼5 folds of expansion in volume when heated. Addition of egg yolk was of benefit to micronize foam size and better crispness. In order to provide better foaming and dehydration, addition of 0.2∼0.5% sodium bicarbonate foaming agent, was proper to result in foam size of 0.5∼0.7mm and foam density of 200∼400/$\textrm{cm}^2$ which gave a good crispness.

• Bulletin of the Korean Chemical Society
• /
• 제35권11호
• /
• pp.3188-3194
• /
• 2014

Compound K (CK) was formulated as polymeric micelles (PM) using Pluronic$^{(R)}$ F-127 to enhance the oral absorption of CK, an intestinal bacterial metabolite of ginseng protopanaxadiol saponin. The physicochemical properties of Ck-loaded PM were characterized and an in vitro transport study using the Caco-2 cell system as well as an in vivo pharmacokinetic study using SD rats was carried out. The hydrodynamic mean particle size of CK-loaded PM (CK-PM) was $254{\pm}23.45nm$ after rehydration and the drug loading efficiency was ca. 99.9%. The FT-IR spectroscopy, X-ray diffraction, differential scanning calorimetry and scanning electron microscopy data supported the presence of a new solid phase in the PM. The $P_{app}$ value of in vitro Caco-2 cell permeation of CK-PM and the oral absorption of CK was enhanced about 1.2-fold and 2.6-fold compared to CK suspension, respectively, showing that the present PM formulation enabled an enhancement of oral CK absorption.

• 대한기계학회논문집
• /
• 제17권1호
• /
• pp.141-152
• /
• 1993

본 연구에서는 축대칭 열전도 고체의 형상설계민감도 해석을 위하여 2차원 문 제를 다룬 Lee, Choi와 Kwak의 방법을 축대칭 문제로 확장하였다.축대칭 형태로 표 시된 직접 및 간접 경계적분방정식의 정식화에 기초하여 전미분방접과 보조변수방법으 로 형상최적화 문제에서 발생하는 일반적인 성능 범함수의 형상설계민감도 공식을 유 도하고, 온도 및 열속의 제한조건에 이를 응용하였다. 제시된 민감도해석방법의 정 확성을 검증하기 위하여 해석적인 해를 갖는 원통문제와 구문제를 다루었는데, 두 문 제에 대하여 민감도 공식을 이용하여 수치계산된 결과를 해석적인 민감도와 비교하였 다. 또한 복잡한 수치해로서 냉각핀(cooling fin)문제를 다루었으며, 민감도 공식에 의한 계산 결과를 유한차분(finite difference)으로 수치미분한 결과와 비교하였다.

• Journal of Pharmaceutical Investigation
• /
• 제31권1호
• /
• pp.7-12
• /
• 2001

Amphotericin B (AmB) is a drug of choice for the treatment of systemic fungal diseases, but its use is considerably limited due to a high incidence of toxicity, particularly nephrotoxicity. It has been demonstrated that the toxicity of AmB is caused by self-aggregated species of the drug and that unaggregated (monomeric) drug is nontoxic but still expresses antifungal activity. Poly (ethylene oxide) (PEO) is a water-soluble polymer, which may impact the aggregation state of AmB. We have studied the aggregation state of AmB as a function of PEO molecular weight and concentration. At 3,000 and 8,000 g/mole, there was minimal or no change of critical aggregation concentration (CAC) of AmB regardless of the concentration of polymer. By contrast at 20,000 g/mole, the CAC of AmB strikingly increased to 24.3 and $37.5\;{\mu}M$ at 5.0% and 10 % w/v of polymer, respectively. The critical overlap concentration (COC) of PEO 20,000 g/mole was 5.5%. It appears that an interaction between monomeric AmB and polymer coil increases above the COC, competing with self-aggregation of the drug. Accordingly, the degree of aggregation of AmB stayed low and the toxicity became less. There was no such effect at 3,000 and 8,000 g/mole of PEO, owing perhaps to small dimensions in comparison to AmB. Based upon these findings, less toxic AmB formulation may be developed by a pharmaceutical technique such as solid dispersion system containing both AmB and PEO 20,000 g/mole.

• 한국농업기계학회:학술대회논문집
• /
• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
• /
• pp.692-700
• /
• 1996

The objective of this study is to develop a systematic purification plant using the metabolism of aerobic microorganisms. This system is subsequently aerated and continuously removes suspended solids and settling sludges caused by aerating pressure at the bottom of a lower pipe (i.e., Continuous Removal of Suspended solids and Settling sludges, CRSS). The CRSS plants are brought out by introducing fine air bubbles into the liquid phase of a lower pipe in the bio-reactor. These plant uses aeration pipe, with multiple inlets to sweep the floor of bio-reactor tank, instead of the conventional scraper mechanisms. The principal advantage of this system is that it can continuously remove very small or light particles that settles completely within a short time. Once the particles have been floated to the surface, they can be moved into the pipe and collected in the settling tank by sequently aerated pressure. The experimental results shows that about 99.0% of the biochemical oxygen demand(BOD), 99.3% of the suspended solid(SS), 92.3% of the total nitrogen(T-N), 99.0% of the turbidity(TU), 100% of the total coliform(TC)and ammonia was respectively removed during aerobic digestion for 9 days. These result indicates that the CRS S plants are very effective for reduction and deodorization of swine wastewater contaminants, and the efflux from CRS S can either be discharged in the river or used as nutrient solution of formulation for plant growth factories. The developed CRSS plant proved to be flexible and it can simply be adapted to any type of biological waste treatment problem.roblem.

• 한국소음진동공학회논문집
• /
• 제19권12호
• /
• pp.1356-1363
• /
• 2009

The aim of this research is to construct eigenfrequency optimization codes for plates with Arbitrary Rank Microstructures. From among noise factors, resonance sound is main reason for floor's solid noise. But, Resonance-elusion design codes are not fixed so far. Besides, The prediction of composite material's capability and an resonance elusion by controlling natural frequency of plate depend on designer's experiences. In this paper, First, using computer program with arbitrary rank microstructure, variation on composite material properties is studied, and then natural frequency control is performed by plate topology optimization method. The results of this study are as followed. 1) Programs that calculate material properties along it's microstructure composition and control natural frequency on composite material plate are coded by Homogenization and Topology Optimization method. and it is examined by example problem. 2) Equivalent material properties, calculated by program, are examined for natural frequency. In this paper, Suggested programs are coded using $Matlab^{TM}$, Feapmax and Feap Library with Homogenization and Topology Optimization method. and Adequacy of them is reviewed by performing the maximization or minimization of natural frequency for plates with isotropic or anisotropic materials. Since the programs has been designed for widely use. If the mechanism between composite material and other structural member is identified, extension application may be possible in field of structure maintenance, reinforcement etc. through application of composite material.