• Journal of Pharmaceutical Investigation
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• v.40 no.3
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• pp.193-200
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• 2010

The objective of this study was to investigate the effects of sample preparation, HPLC conditions and peak measurement methods upon determining progesterone content of poly-d,l-lactide-co-glycolide microspheres. A series of the microspheres with different formulations was first prepared. To determine their actual drug contents, the microspheres were dissolved in tetrahydrofuran and diluted with various amounts of methanol to precipitate the polymer. After removal of polymeric precipitates, the filtrates were subject to HPLC analysis under versatile experimental conditions. Interestingly, the composition of a sample solution (e.g., the ratio of methanol to tetrahydrofuran) affected the magnitudes of both peak fronting and peak broadening of progesterone. Its peak became broader and more asymmetrical at lower methanol:tetrahydrofuran ratios. Furthermore, its peak height was influenced by the proportion of tetrahydrofuran in a sample solution. Such problems encountered with tetrahydrofuran were exacerbated when a larger volume of the sample solution was injected onto an analytical column. Under our experimental conditions a peak area measurement provided more accurate and reliable determination of progesterone content in various microspheres than a peak height determination. Optimizing the composition of a sample solution, HPLC chromatographic conditions and peak analysis methods was a prerequisite to an accurate determination of progesterone encapsulated within microspheres.

• Progress in Superconductivity
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• v.3 no.1
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• pp.36-40
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• 2001

We have studied vortex dynamics in$ Bi_2$$Sr_2$$CaCu_2$O$_{8}$single crystals of unirradiated and irradiated samples by using 100 $\times$ $100\mu\textrm{m}^2$Hall sensor. Doses equivalent magnetic fields are 20 G, 100 G and 1 kG. In the magnetization measurement, a second magnetization peak (SMP) was observed in unirradiated, 20 G dose and 100 G dose samples in contrast to 1 kG dose sample. In the unirradiated sample, the SMP was observed in the range of 18 K ~ 35 K and the amplitude of the SMP decreased with increasing temperature. With increase of the irradiation dose, temperature region and sharpness of the SMP were reduced. In the magnetic relaxation measurement, we observed that the normalized relaxation rate S decreased with increasing the irradiation dose. Our results suggest that the vortex dynamics is not greatly affected by low-density columnar defects.s.

• Proceedings of the KSAR Conference
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• 2004.06a
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• pp.279-279
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• 2004

성장중인 수토끼에서 성성숙 전후의 혈청내 IGF-I 수준과 정자형성의 변화를 12주령부터 28주령까지 2주 간격으로 조사하였다. IGF-I 수준 측정은 non-extraction IGF-I ELISA kit(Biognostic System, Lab, USA)를 이용하였으며 정소내 정자형성은 biopsy needle(22G×3¹/₂ 72㎜×8.89㎝, Becton Dickinson, USA)로 채취한 정소조직을 fled ctyometric ploidy analysis로 DNA histogram을 4개 peak(peak Ⅰ과Ⅱ :1N, peak Ⅱ :2N, peak Ⅳ : 4N, peak Ⅲ과 Ⅳ사이 : S기)로 구분하였다. (중략)

• Journal of Magnetics
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• v.2 no.4
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• pp.111-115
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• 1997

The electronic structure of the Kondo insulator CeNiSn has been investigated by using photoemission spectroscopy. A satellite feature is observed in the valence band spectrum about 6 eV below the Ni 3d main peak, indicating a strong Ni 3d Coulomb correlation in CeNiSn. The Ce 4f partial spectral weight exhibits three peak structures, including one due to the 4f1\longrightarrow4f0 transition, another near EF, and the other which overlaps the Ni 3d main peak. We interpret the peak near EF as reflecting mainly the Ce 4f/Sn 5p hybridization, whereas that around the ni 3d main peak as reflecting both the Ce 4f/Ni 3d and Ce 5d/Ni 3d hybridization. Yield measurements across the 4d\longrightarrow4f threshold indicate the Ce valence to be close to 3+. The prominent Fermi edge suggests a metallic ground state in CeNiSn.

• Proceedings of the KIEE Conference
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• 1993.07b
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• pp.886-888
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• 1993

Recently current mode control is widely adopted in switching power converter because of inherent stablity and ability of parallel operating. There are several ways in current mode control. One of them, peak current control is chiefly employed. Peak current mode control converter usually senses and controls peak inductor current. But there is peak-to-average current errors. Therefore peak current control needs compensation ramp correcting the errors. Average current mode control eliminates these problems, and is constructed by simple structures. This paper will describe the behavior of a simple average current mode boost converter and introduce the design techniques.

• Fire Science and Engineering
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• v.27 no.6
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• pp.57-63
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• 2013

This study was performed to test the combustive properties of Pinus rigida specimens treated with piperazinomethyl-bis-phosphonic acid (PIPEABP), methylpiperazinomethyl-bis-phosphonic acid (MPIPEABP), and N,N-dimethylethylene-diaminomethyl-bis-phosphonic acid (MDEDAP). Pinus rigida Plates were painted in three times with 15 wt% alkylenedi-aminoalkyl-bis-phosphonic acid solutions at the room temperature. After drying specimen treated with chemicals, combustive properties were examined by the cone calorimeter (ISO 5660-1). It was indicated that the specimens treated with chemicals showed the later time to peak mass loss rate ($TMLR_{peak}$) = (315~420) s than that of virgin plate by reduc-ing the burning rate except for $TPMR_{peak}$ (280 s) treated with DMDAP. In adition, the specimens treated with chemicals showed both the higher total smoke release rate (TSRR) (407.3~902.0) $m^2/m^2$ and $CO_{mean}$ production (407.3~902.0) $m^2/m^2$ than those of virgin plate. Especially, for the specimens treated with PIPEABP, 1st-smoke production rate (1st-SPR) (0.1250~0.1297) g/s was lower than that of virgin plate, while the 2nd-SPR (0.183 g/s) was higher. Thus, It is supposed that the combustion-retardation properties were improved by the partial due to the treated alkylenediaminoalkyl-bis-phos-phonic acids in the virgin Pinus rigida.

• Resources Recycling
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• v.13 no.6
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• pp.16-25
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• 2004

In this study, nano-sized indium oxide powder with the average particle size below 100 nm is prepared from the indium chloride solution by the spray pyrolysis process. The effects of the concentration of raw material solution, the nozzle tip size and the air pressure on the properties of powder were studied. As the indium concentration of the raw material solution increased from 40 g/l to 350 g/l, the average particle size of the powder gradually increased from 20 nm to 60 nm, yet the particle size distribution appeared more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the nozzle tip size increased from 1 nm to 5 nm, the average particle size of the powder increased from 40 nm to 100 nm, the particle size distribution was much more irregular, the intensity of a XRD peak increased and specific surface area decreased. As the air pressure increased from 0.1 kg/cm$^2$ to 0.5 kg/cm$^2$, the average particle size of the powder varies slightly upto 90~100 nm. As the air pressure increased from 1 kg/cm$^2$ to 3 kg/cm$^2$, the average particle size decreased upto 50~60 nm, the intensity of a XRD peak decreased and the specific surface area increased.

• Korean Journal of Medicinal Crop Science
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• v.19 no.1
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• pp.1-8
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• 2011

Biological characteristics of 5 Zanthoxylum schinifolium (Zs) fruits such as Z1 (early August), Z2 (middle August), Z3 (middle September), Z4 (early October) and Z5 (middle October) according to harvesting time were evaluated. As fruits ripened, average weight of Zs increased from 4.8mg (Z1) to 50.7mg (Z5), while moisture contents decreased from 74.6% (Z1) to 55.2% (Z5). Crude fat contents of the fruits during ripening increased from 1% (Z1) to 10.6% (Z5). The major fatty acids in Zs were palmitic (C16:0), palmitoleic (C16:1), oleic (C18:1), and linoleic (C18:2) acids. Linoleic acid (C18:2) was a main fatty acid in Z1 and Z2, whereas oleic acid (C18:1) was found as a main one in the other Zs. The ratio of unsaturated fatty acid to total fatty acids increased from 60% (Z1) to 80% (Z3~Z5) during ripening. Among ripening stages, Z4 had the highest contents of total fatty acids ($3,355{\mu}g/g$) and total unsaturated fatty acids ($2,753{\mu}g/g$). Forty six volatile compounds in Zs were also identified. The major volatile compounds were ${\alpha}-pinene$, ${\beta}-myrcene$, ${\beta}-ocimene$, 2-nonanone, estragole, 2-undecanone, and ${\beta}-caryophyllene$. Major volatile components of Z1 were ${\beta}-ocimene$ (20.8 peak area %) and ${\alpha}-pinene$ (9.7 peak area %). In Z2, estragole (30.1 peak area %) was a main volatile compound, but the contents of ${\alpha}-pinene$ (0.4 peak area %), ${\beta}-myrcene$ (0.3 peak area %), and ${\beta}-ocimene$ (0.6 peak area %) were lower than those in Z1. Especially, estragole used as perfumes and as a food additive for flavor was drastically increased to 91.2 (Z3) and 92% (Z4) as fruits ripened.

• The Korean Journal of Ecology
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• v.28 no.6
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• pp.347-351
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• 2005

The amounts of organic carbon and several nutrients in litterfall on the forest floor of Quercus mongolica forest were assessed for two years from 1998 through 2000 in Mt. Songnisan National Park in Korea. The amounts of organic carbon (C) in litterfall were the highest in autumn with the values of $150.4g/m^2$ (62.6%) in 1998 and $219.2g/m^2$ (61.0%) in 1999. In winter, organic C was the lowest with the values of $16.3g/m^2$ (6.8%) in 1998 and $12.5g/m^2$ (6.7%) in 1999. It was estimated that the organic C added to forest floor via litterfall was 240.1 $g{\cdot}m^{-2}yr^{-1}$ and 186.6 $g{\cdot}m^{-2}yr^{-1}$ 1998 and 1999, respectively. The amounts of nitrogen (N) in litterfall were the highest in autumn with the values of 5.9 $g/m^2$ (58.0%) in 1998 and 5.2 $g/m^2$ (62.3%) in 1999. The amount of phosphorus (P) in litterfall showed its peak in autumn with 0.19 $g/m^2$ (52.9%) in 1998 and 0.11 $g/m^2$ (52.6%) in 1999. The amount of P returned to forest floor via litterfall was 0.35 $g{\cdot}m^{-2}yr^{-1}$ in 1998 and 0.22 $g{\cdot}m^{-2}yr^{-1}$ in 1999. The amount of potassium (K) in litterfall showed its peak in autumn with 0.57 $g/m^{2}$ (53.8%) in 1998 and 0.42 $g/m^2$ (55.3%) in 1999. The amounts of K returned to forest floor via litterfall was 1.11 $g{\cdot}m^{-2}yr^{-1}$ in 1998 and 0.81 $g{\cdot}m^{-2}yr^{-1}$ in 1999.

• Fire Science and Engineering
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• v.28 no.3
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• pp.55-61
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• 2014

This study was performed to test the combustive properties of pinus rigida specimens treated with methylpiperazinomethyl-bis-phosphonic acid $M^{n+}$ ($PIPEABPM^{n+}$)s and methylpiperazinomethyl-bis-phosphonic acid (PIPEABP). Pinus rigida Plates were painted in three times with 15 wt% $PIPEABPM^{n+}s$ and PIPEABP solutions at the room temperature respectively. After drying specimen treated with chemicals, combustive properties were examined by the cone calorimeter (ISO 5660-1). It was indicated that the specimens treated with $PIPEABPM^{n+}s$ showed the lower speed to peak mass loss rate ($MLR_{peak}$), (0.104~0.121) g/s than that of PIPEABP plate. In adition, the specimens treated with $PIPEABPM^{n+}s$ showed both the lower total smoke release rate (TSRR), (224.4~484.0) $m^2/m^2$ and $CO_{mean}$ production (0.0537~0.0628) kg/kg than those of PIPEAB plate. Especially, for the specimens treated with $PIPEABPM^{n+}$ by reducing the smoke production rate except 2nd-smoke production rate (2nd-SPR), (0.0254~0.02270) g/s treated with $PIPEABPNi^{2+}$, 2nd-SPR (0.0117~0.0146) g/s was lower than that of PIPEABP plate. Thus, It is supposed that the combustion-retardation properties were improved by the partial due to the treated $PIPEABPM^{n+}s$ in the virgin plate.