• Current Photovoltaic Research
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• 제2권1호
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• pp.36-39
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• 2014

Formation mechanism of residual carbon layer, frequently observed in the $CuInSe_2$ (CIS) thin film prepared by direct solution coating routes, was investigated in order to find a way to eliminate it. As a model system, a methanol solution with dissolved Cu and In salts, whose viscosity was adjusted by adding ethylcellulose (EC), was chosen. It was found that a double layer, a top metal ion-derived film and bottom EC-derived layer, formed during an air drying step presumably due to different solubility between metal salts and EC in methanol. Consequently, the top metal ion-derived film acts as a barrier layer inhibiting further thermal decomposition of underlying EC, resulting a formation of bottom carbon residue layer.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 춘계학술대회 논문집
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• pp.441-443
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• 2008

A non-vacuum process for fabrication of $CuInSe_2$ (CIS) absorber layer from the corresponding Cu, In solution precursors was described. Cu, In solution precursors was prepared by a room temperature colloidal route by reacting the starting materials $Cu(NO_3)_2$, $InCl_3$ and methanol. The Cu, In solution precursors were mixed with ethylcellulose as organic binder material for the rheology of the mixture to be adjusted for the doctor blade method. After depositing the mixture of Cu, In solution with binder on Mo/glass substrate, the samples were preheated on the hot plate in air to evaporate remaining solvents and to burn the organic binder material. Subsequently, the resultant CI/Mo/glass sample was selenized in Se evaporation in order to get a solar cell applicable dense CIS absorber layer. The CIS absorber layer selenized at $530^{\circ}C$ substrate temperature for 30 min with various Se gas evaporation temperature was characterized by XRD, SEM, EDS.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2009년도 춘계학술대회 논문집
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• pp.19-22
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• 2009

A non-vacuum process for fabrication of $CuIn_xGa_{1-x}Se_2$ (CIGS) absorber layer from the corresponing Cu, In, Ga solution precursors was described. Cu, In, Ga precursor solution was prepared by a room temperature colloidal route by reacting the starting materials $Cu(NO_3)_2$, $InCl_3$, $Ga(NO_3)$ and methanol. The Cu, In, Ga precursor solution was mixed with ethylcellulose as organic binder material for the rheology of the mixture to be adjusted for the doctor blade method. After depositing the mixture of Cu, In, Ga solution with binder on Mo/glass substrate, the samples were preheated on the hot plate in air to evaporate remaining solvents and to burn the organic binder material. Subsequently, the resultant CIG/Mo/glass sample was selenized in Se evaporation in order to get a solar cell applicable dense CIGS absorber layer. The CIGS absorber layer selenized at $530^{\circ}C$ substrate temperature for 1h with various metal organic ratio.

• Journal of Pharmaceutical Investigation
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• 제35권3호
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• pp.157-163
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• 2005

The pellets with multiple drug release system (MDRS) of Diltiazem. HCl which consist of immediate drug release layer, drug reservoir layer and controlled release rate membrane, were prepared by using CF-Coater. As main factors for more effective MDRS of Diltiazem. HCl, ethylcellulose was used for the controlling drug release rate, and diethylphthalate was used for plasticizer, respectively. In vitro evaluation study was performed by comparative dissolution test between our test MDRS and reference Diltiazem. HCl preparation. The physical tests were performed using FT-IR and SEM. In vivo evaluation was also performed by observing the behavior of a plasma drug concentration after oral administration. The bioavailability was determined by analyzing the blood sample after oral administration to healthy, male volunteers once a day. As a result, there were no significant differences in bioequivalence parameters $(AUC_{\infty},\;C_{max},\;t_{1/2})$ between two systems. It might be concluded that our MDRS of Diltiazem. HCl could be an alternative delivery system to reference drug preparation.

• Journal of Pharmaceutical Investigation
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• 제38권3호
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• pp.177-182
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• 2008

The purposes of this study were to prepare dual-layered coated compact pellets containing three nutrients Glucose, Chromium picolinate, Vitamin C) for rumen bypass. The core compact pellets were prepared by an extrusionspheronization method and then double layered coated with pH independent EC (ethyl cellulose) and pH-dependent polymers ($Eudragit^{(R)}$ E100) using a fluid-bed spray coater. Depending on the coating levels of EC and $Eudragit^{(R)}$ E100, release profiles were variable in simulated rumen (pH 6.8) and abomasums (pH 2.0) fluid using USP apparatus I (basket method). When compact pellets were coated with EC (about 10% level in inner layer) and then $Eudragit^{(R)}$ E100 (20% level in outer layer) in a dual-layered manner, rumen-bypass delivery resisting rumen fluid followed by release in abomasums fluid could possible. The friability was also satisfactory based on chewing behavior of ruminants. The dual-layered coated compact pellets showed smooth surface and distinct inner/outer layers using scanning electron microscopy (SEM). The current rumen bypass delivery system can be also applicable to deliver other nutrients in ruminants.

• 약학회지
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• 제40권4호
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• pp.400-410
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• 1996

In oder to develop the controlled release of drugs from the suppositories, in vitro drug release and in vivo absorption in rabbits were investigated. Various suppo sitory forms with hollow cavities, into which drugs in the form of fine powder or solid dispersion system(SDS) could be placed, were utilized. The oleaginous Witepsol H-15 (WH-15) as a base, and indomethacin (IDM) of a very slightly soluble drug and propranolol-HCL (PPH) of a very soluble drug were employed as model drugs. The in vitro drug release showed that the cumulative release amount of PPH from PPH-(methylcellulose) MC-SDS and PPH-(ethylcellulose) EC-SDS hollow type suppositories reached 40% and 12% in 6 hrs,respectively. On the other hand, the drug release for a conventional suppository was 80% in 6 hrs. For the IDM suppositories,the cumulative drug release from IDM-(polyvinylpyrrolidone) PVP-SDS hollow type suppositories reached 99% in 24 hrs, whereas that from a conventional suppository reached 85%. An in vivo experiment with rabbits showed that IDM-PVP-SDS hollow type suppository delayed the absorption of IDM, significantly. The $t_{max},\;C_{max}\;and\;AUC_{0{\to}8}$ of IDM-PVP-SDS suppository were 60 min, 12.12${\mu}g$/ml and 2657${\mu}g$/ml/min, respectively. The $t_{max},\;C_{max}\;and\;AUC_{0{\to}8}$ of controlled group were 20 min, 15.49${\mu}g$/ml and 2190${\mu}g$/ml/min, respectively.

• 한국세라믹학회지
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• 제39권5호
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• pp.467-472
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• 2002

다이아몬드 연마 필름(diamond lapping film)으로 긴 탄소나노튜브를 절단하고 이를 Scanning Electron Microscope(SEM)으로 관찰했다. 절단된 탄소나노튜브를 ${\alpha}$-terpineol을 용매로 ethyl cellulose를 바인더로 사용하여 제조한 페이스트를 스크린 프린팅과 주사 사출법으로 유리 기판에 도포하였다. 스크린 프린팅으로 인쇄된 선에 존재하는 절단된 탄소나노튜브를 기판에 대해 수직 배향을 시키기 위하여 사포, 다이아몬드 연마 필름을 사용하여 마찰시키거나 접착성이 있는 테이프를 이용하여 접촉시켰다가 분리 하는 방법을 시도하였다. SEM으로 탄소나노튜브의 배향 특성을 관찰한 결과 주사 사출법과 스크린 프린팅 후 다이아몬드 연마 필름을 사용하여 후처리하는 간편한 방법으로 탄소나노튜브의 우수한 수직배양이 이루어짐을 알 수 있었다.

• 공업화학
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• 제10권8호
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• pp.1114-1118
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• 1999

플라즈마 디스플레이 패널(PDP)의 격벽(barrier rib)은 일정한 선폭과 높이를 가져 균일한 방전 공간을 제공하고, 인접한 셀 간의 전기적, 광학적 혼선(crosstalk)을 방지하기 위해 PDP의 하부 유리 기판 패널에 들어가는 구조물이다. 본 연구에서는 사진식각(photolithography)법으로 격벽을 형성하는데 필요한 감광성 격벽 페이스트가 제조되었다. 페이스트는 바인더 고분자인 에틸셀룰로오즈를 BC/BCA = 30/70 wt %인 혼합 용매에 15 wt %로 용해한 다음 관능성 단량체로서TPGDA/PETA = 50/50 wt % 혼합물, 광개시제로서 Irgacur 651 및 격벽 분말을 도입한 다음 전체를 균일하게 분산시켜 제조하였다. 감광성 격벽 페이스트의 각 성분, 조성 및 공정을 최적화하여 소성 후 높이 약 $100{\mu}m$ 에 이르는 PDP용 격벽을 고해상도로 사진식각법으로 얻을 수 있었다.

• Archives of Pharmacal Research
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• 제28권5호
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• pp.619-625
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• 2005

Beads loaded with the water-soluble drug, phenylpropanolamine HCl (PPA), were prepared using an extruder and double arm counter-rotating roller modified from a traditional pill machine. The mean diameter of the cylindrical rod-like extrudate from the ram extruder was 3 mm; that of the uncoated bead after cutting and spheronization by the modified double arm counter-rotating roller was 3.26~3.28 mm. Although the surface of the beads was moderately rough and irregular, some exhibited hump-shaped protrusions, the sphericity was acceptable (roundness 1.15) and adequate for the subsequent coating process. An increase in mean diameter of the coated beads and improvements in friability and sphericity were observed in proportion to the amount of coating material applied (ethylcellulose or Eudragit？？ RS 100). It was also found that the release rate of PPA from the coated beads could be controlled by the amount and type of coating materials applied or with the incorporation of Eudragit ？？ RS 100 into the core matrix. Further modifications to the double arm counter-rotating roller, including adjustment of the rotation speed and distance between the rollers, would yield smaller uncoated beads with improved roundness and surface roughness. In conclusion , the present method could be potentially applied to prepare controlled release drug delivery beads or pellet dosage forms.

• Journal of Pharmaceutical Investigation
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• 제26권4호
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• pp.299-308
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• 1996

In order to develop the controlled release of a drug from the suppsitories, in vitro drug release and in vivo absorption in rabbits were investigated. Various suppository forms with hollow cavities, into which drugs in the form of fine powder or solid dispersion system(SDS) could be placed, were utilized. The polyvinyl alcohol(PVA) hydrogel as a base, and propranolol HCl(PPH) as a model drug were employed. In vitro drug dissolution studies showed that the dissolved amounts(%) of PPH from PPH-methylcellulose(MC)-SDS and PPH-ethylcellulose(EC)-SDS reached 100% and 63% in 4.5-hours, respectively. In the relative strength test for PVA hydrogel, PVA hydrogel became harder and more rigid when the number of freezing-thawing cycles and the ratio of PVA 2000 were increased. In vitro drug release profile revealed that the release rate(%) of PPH from PPH-EC-SDS and PPH-MC-SDS hollow type suppositories were sustained. The release amount(%) of PPH from PPH-EC-SDS hollow type suppositories was not affected by storage time, but since the use of hydrophilic MC made PPH diffuse into the hydrogel after it absorbed the water of base, the various release patterns were appeared as the storage time went by. In vivo absorption experiments with rabbits showed that PPH-EC-SDS(PPH : EC=1:3) hollow type suppository delayed the absorption of PPH, significantly. The $C_{max}$, $AUC_{0{\rightarrow}8}$ and MRT of PPH powder hollow type suppository were $196.37{\pm}5.63\;ng/ml$, 1105.26 ng/ml/min and 8.66 min, respectively. The $C_{max}$, $AUC_{0{\rightarrow}8}$ and MRT of PPH-EC-SDS(PPH : EC=1:3) were $91.30{\pm]14.14\;ng/ml$, 554.69 ng/ml/min, 235.99 min, respectively.