• Journal of Pharmaceutical Investigation
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• 제39권3호
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• pp.161-166
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• 2009

This study is to specify the criteria and testing methods of WHW extract which has a potency as a therapeutic agent for chronic renal failure. The determination of specifications of WHW extract is mostly important because of the quality assurance. Three batches of WHW extract were obtained by the extraction at $98^{\circ}$C for 3 hr using water from mixture of 15 herbal medicines including Codonopsis Pilosulae Radix, Salviae Radix, Pinelliae Rhizoma, Coptidis Rhizoma, Evodiae Fructus, Epimedii Herba, Rhei Rhizoma, Perillae Herba, Glycyrrhizae Radix, Artemixiae capillaris Herba, Alimatis Rhizoma, Hoelen, Atractylodies Rhizoma alba, Polyporus and Cinnamomi Ramulus, subsequently, vaccum-dried for 15 hr. The yield of WHW extracts was 24.53% on the average. The identification of each herbal medicine of WHW extract was performed by modification of Korean Pharmacopeia IX (KP IX). The assay of WHW extract was performed using standard such as berberine, icariin, glycyrrhizin, and cinnamic acid of indicative herbal medicines by modification of KP IX, too. As well as, paticle size classification test was carried out to indicate the boundary of particle size of WHW extract and the particle size of WHW extract more than 50% showed the 140 ${\mu}$m. Taken together, WHW extract could be prepared reproducibly and assurable if follows the presented extraction and drying steps and its specifications were satisfied with the indicated criteria.

• 대한기계학회논문집B
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• 제25권12호
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• pp.1813-1820
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• 2001

The purpose of this study was to investigate the significant characteristics in atomization process of industrial etching spray fur the design or Precise pressure-swirl nozzles. The experiment was carried out with different viscosities and densities of the liquid. The macro characteristics of liquid spray, such as the spray angle and breakup process were captured by PMAS and the micro characteristics of liquid spray. such as droplet size and velocity measurements were obtained by PDA. The droplet axial and radial velocity and SMD were measured along axial and radial direction. The RMS of two velocities was measured along radial direction. It was found that the fluid with higher kinematic viscosity resulted in the larger SMD and the lower mean droplet velocity. And we could divide breakup processes into three regions that is atomization, non-dilution and dilution one in spray of pressure-swirl nozzle. The radial as well as axial velocity of droplet played an important role in the atomization process of higher kinematic viscosity fluid.

• 동굴
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• 제34권35호
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• pp.78-104
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• 1993

Analysis of one sinkhole, the Dodgeville sinkhole, developed in Ordovician dolostones in the Driftless Area of Wisconsin in the Upper Midwest'd Driftless Area reveals homogenous clayey sediment fills reflecting a range of dissolutional processes during the Quaternary or Pre-Quaternary. Granulometric analysis, graphical moments statistics, carbonate minerals, ana sand grain lithology were used to differentiate sinkhole sediment sources and modes of accumulation. Sediments in the dolostone sinkholes developed by dissolution. Sediments contain two major types of sediments : residual redish clay( autogenic sediments) and aeolian silt (allogenic sediments). The massive clay is generated from the weathered dolostone bedrocks as a in situ materials. The loessial silt is mostly derived from transportation of the surrounding surface materials, with some evidences of penetrated deposition. Unlike the collapsed sandstone sinkholes (Oh et al., 1993), dolostone sinkholes reveal homogenous, autogenic clay materials, and a geochemical composition indicative of in situ autogenic karstification. Dolostone sinkhole si1ts (26.9%) and sands (34.9%) are derived from weathered Plattevi1le-Galena dolostones, and contain high carbonate(37.5%), chert (57.2%) and lead ore (3%). Graphical moments statistics for sorting, skewness, and kurtosis indicate that sand grains from dolostones were derived entirely from local bedrock by in situ dissolution. Upper sinkhole sediments are pedagogically very young as carbonate is unleashed. Materials of the sinkhole sediment are definitely inherited from internal dolostones by dissolution and weathering, because not only a granulomatric comparison of dolostone and sandstone sediments demonstrates that they have heterogeneous paticle size distributions, but also 1ithologic analyses displays they differ completely.

• 대한토목학회논문집
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• 제13권1호
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• pp.173-178
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• 1993

다짐특성과 CBR값에 의해 얻어진 비회와 저회의 적정 혼합비는 5:5 또는 석탄회 재질에 따라서 6:4 까지도 가능하였다. 그러나 이들 혼합회에는 실트 크기의 입자를 상당히 많이 함유하게 되어, 입도분포등의 종래 기준에 의하면 동상현상에 의한 동해를 받기 쉬울 것으로 여겨진다. 본 연구는 적정비로 혼합한 석탄회를 노상재로서 사용하기 위하여 다짐할 경우의 동상성에 대해 실험적으로 검토한 것이다. 또한, 이들 혼합회를 동상의 피해에 대해 안전한 재료로 만들기 위하여 필요한 적정 시멘트 첨가량도 구하였다. 적정비로 혼합한 석탄회는 동상현상에 의한 동해를 받기 쉬운 재료이지만, 4% 정도의 시멘트를 첨가함으로써 동상량은 만족할 만큼 크게 줄일 수 있었다. 동상량은 혼합회의 강도와는 반비례적인 관계에 있고, 시료의 동결선속으로 공급되는 수분을 제한할 수 있을 정도의 작은 투수계수 k내에서는 동상량과 log k 는 비례관계에 있다고 할 수 있다.

• 한국자기학회지
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• 제10권1호
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• pp.11-15
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• 2000

수분사법으로 제조된 13Cr-1.5Nb-Fe 합금분말을 수소분위기 하에서 환원처리 하였다. 분말특성이 조사된 환원분말을 이용하여 자기코아를 제작한 후 약 $10^{-5}$Torr의 진공분위기에서 소결하였다. 자기코아의 교류자기특성을 조사하기 위하여 투자율과 자기손실을 조사하였다. 환원분말의 입도분포는 약 70$\mu\textrm{m}$에서 50% vol.을 나타내며, 포화자화 값은 약160 emu/g이었다. 10ton/$\textrm{cm}^2$ 성형압력, 1,20$0^{\circ}C$ 소결온도에서 제작된 자기코아의 교류투자율은 주파수, f=1 kHz, 인가자장, H$_{a}$ =5 Oe에서 400이다. 또한 동조건에서 제작된 자기코아의 교류자기이력손실은 유도자화, B$_{m}$ =80G에서 0.12mW/cc이다.

• 한국식품과학회지
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• 제32권6호
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• pp.1291-1297
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• 2000

묵 형성 전분의 입도분포, 신속점도계에 의한 호화성질 및 전분 겔의 텍스쳐 특성을 비교하고 전분 겔의 텍스쳐 특성과의 상관관계를 조사하였다. 전분의 입도분포에서 녹두 전분 입자는 17.04 미크론 입자를 정점으로 하나의 피크를 보였으나, 도토리와 메밀 전분입자는 세 개의 피크를 보였다. 신속점도계에 의한 호화성질을 보면 일정한 농도에서 녹두 전분은 다른 전분보다 최고점도가 크며, 최저점도와 최종점도가 작고 breakdown과 setback이 컸다. 도토리 전분은 최고점도와 breakdown이 가장 작았다. 메밀 전분은 최고점도가 녹두 전분과 비슷하였으나 최저점도와 최종점도는 도토리 전분과 비슷하였다. 일정한 최고점도에서의 호화성질을 보면 녹두 전분은 최저점도와 최종점도가 가장 낮았고, breakdown과 setback은 가장 컸다. 도토리와 메밀 전분은 최저점도와 breakdown이 비슷하였으나, setback은 도토리 전분이 컸다. 전분 겔(농도 10.7%)의 텍스쳐 특성 값을 보면 녹두 전분은 탄성을 제외한 모든 특성에서 다른 전분과 유의적으로 달랐으며 응집성은 가장 작았고, 경고, 검성과 부서짐성은 가장 컸다. 도토리와 메밀 전분은 경도와 검성에서 유의적으로 달랐으며 전자가 경도와 검성이 모두 컸다. 전분 겔의 경도는 최저점도 및 최종점도와 음의 상관을, setback과는 정의 상관을 보였다.

• Journal of Welding and Joining
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• 제15권5호
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• pp.134-143
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• 1997

The formation of thick alloyed layer with high Si content have been investigated on the surface of Al alloy (A5083) plate by PTA process with Si powder. Hardening characteristics and wear resistance of alloyed layer was examined in relation to the microstructure of alloyed layer. Thick hardened layer in mm-order thickness on the surface of A5083 plate can be formed by PTA process with wide range of process condition by using Si powder as alloying element because of eutectic reaction of Al-Si binary alloy. High temperature and rapid solidification rate of molten pool, which are features of PTA process, enable the formation of high Si content alloyed layer with uniform distribution of fine primary Si paticle. High plasma arc current was beneficial to make the alloyed layer with smooth surface appearance in wide range of powder feeding rate, because enough volume of molten pool was necessary make alloyed layer. Uniform dispersion of fine primary Si particle with about 30${\mu}{\textrm}{m}$ in particle size can be obtained in layer with Si content ranging from 30 to 50 mass %. Hardness of alloyed layer increased with increasing Si content, but increasing rate of hardness differed with macrostructure of alloyed layer. Wear resistance of alloyed layer depended on $V_{si}$(volume fraction of primary Si) and was remarkably improved to two times of base metal at 20-30% $V_{si}$ without cracking, but no more improvement was obtained at larger $V_{si}$.