• Proceedings of the Korean Vacuum Society Conference
• /
• 2016.02a
• /
• pp.379.2-379.2
• /
• 2016

The Ni oxide/PVP nanofibers were synthesized by sol-gel and electrospinning technique. The obtained Ni oxide/PVP (polyvinylpyrrolidone) nanofibers were calcined to remove the PVP compound at 873 and 1173 K. The Ni oxide/PVP nanofibers were analyzed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS). The SEM images showed that the mat form was prepared by calcination of Ni oxide/PVP nanofibers at 873 K. And the crystal structure of Ni oxide at 1173 K was also confirmed by SEM images. XRD results shows the crystallinity of metallic Ni and NiO. TEM images also verified the crystal phase of Ni and Ni oxide. XP spectra revealed that the oxidation state of Ni to conclude the chemical composition of Cu oxide nanofibers.

• Proceedings of the Safety Management and Science Conference
• /
• 2001.05a
• /
• pp.319-324
• /
• 2001

High surface area and high pore volume activated carbon was prepared by KOH activation of rice hull. The electrodes were fabricated by compounding the commercial and rice hull activated carbons with PVdF and PVdF-PVP mixed binders without addition of conductivity improver. The electrodes fabricated with rice hull activated carbon and PVdF-PVP mixed binders showed the best performance because the PVP played as a pore-forming agent. The electrode exhibited excellent electrochemical characteristics having 7.9 W.h/kg of energy density, 33.5 F/g of speific capacitance, 0.7 $\Omega$ of ESR and good efficiency of self-discharge compared with that fabricated with commercial activated carbons.

• Steel and Composite Structures
• /
• v.9 no.1
• /
• pp.77-87
• /
• 2009

This paper reports the results of an experimental investigation of the polyvinylpyrrolidone (PVP) influence on the steel reinforcement corrosion and compressive strength of concretes in sulphate medium. The effect of admixture of PVP in concrete on the corrosion resistance of steel reinforced concrete was assessed by measuring electrochemical test during 60 days immersion in two different external solutions. AC impedance spectrum indicated that the resistance of PVP mixed electrodes were higher than those without PVP. The compressive strength of concrete specimens containing PVP was measured and an increase of 19%~24% was observed.

• Korean Journal of Optics and Photonics
• /
• v.6 no.1
• /
• pp.45-49
• /
• 1995

시간 상관 단일 광자 계수법을 사용하여 PVP/C/sub 2/H/sub 5/OH와 PEG/H/sub 2/O 혼합 용매에 위치한 rhodemine 6G 분자의 회전 재배열 시간을 측정하였다. 주어진 온도에서 혼합비를 변화시키면서 측정한 결과, PEG/H/sub 2/O와 PVP/C/sub2/H/sub 5/OH에서 각각 회전 이완 시간이 혼합액의 점성도에 선형적으로 비례하지 않는 것으로 관측되었다. 고분자 주의에 cluster가 형성된다는 관점에서 혼합비에 따른 회전 이완 시간의 변화를 설명하였다.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.04b
• /
• pp.33-34
• /
• 2009

Hybrid nanofibers made of $Cu_2O$ and polyvinyl pyrrolidone were fabricated by electrospinning. The current magnitude of the $Cu_2O$-PVP hybrid nanofibers is 10 times larger than that of pure PVP nanofibers. In addition, $Cu_2O$-PVP nanofibers possess high sensitivity to air at room temperature.

• 한국정보디스플레이학회:학술대회논문집
• /
• 2002.08a
• /
• pp.184-187
• /
• 2002

In this work, the electrical characteristics of organic thin film transistors with the stacked organic gate insulators have been studied. PVP(Polyvinylphenol) and polystyrene were used as gate insulating materials. Both the high dielectric constant of PVP and better insulating capability of polystyrene were compensatorily adopted in two different stacking orders of PVP-polystyrene and polystyrene-PVP. The output characteristics of the device with the stacked gate insulator showed substantial improvement compared with those of the devices with either PVP or polystyrene gate insulator: Furthermore, these stacked organic gate insulators can differently affect the TFT characteristics with the stacking orders. The electrical properties of TFTs with organic gate insulators stacked in different orders are discussed.

• Journal of Pharmaceutical Investigation
• /
• v.9 no.1
• /
• pp.7-14
• /
• 1979

The relative efficacy on the renal function of rabbits by oral administration of furosemide and 1 : 2 furosemide-PVP coprecipitate was compared by measuring the urine volume in response to maximal response and the amounts of electrolytes excreted in urine. The furosemide produced a rapid onset, short duration of diuresis, in contrast, the 1: 2 furosemide-PVP coprecipitate, a rapid onset, significantly larger magnitude, and longer duration of diuresis and therefore the bioavailability of furosemide from the coprecipitate were increased significantly. The average urine volume and the amount of sodium and potassium excreted in urine were increased about 2.9-, 14.8-, and 1.8-fold from furosemide, and about 6.2-, 24.2-, and 3.6-fold from 1 : 2 furosemide- PVP 40,000 coprecipitate, rerpectively, comparing by their control values.

• Proceedings of the Membrane Society of Korea Conference
• /
• 1998.04a
• /
• pp.59-60
• /
• 1998

1. 서론 : 고분자 분리막은 대부분 immersion precipitation에 의한 상분리법으로 제조한다. 이 방법으로 제조한 막은 표면으로 갈수록 치밀한 구조를 갖고, 하부층에는 많은 경우 macrovoid가 형성된다. 이러한 연구의 하나로 PVP와 같은 고분자 첨가제를 고분자 용액에 첨가하여 막을 제조하는 방법에 대한 연구가 Boom 등을 중심으로 이루어져 왔는데, 대부분의 경우 macrovoid가 줄어들고 막의 porosity가 증가하는 결과를 보여준다. 본 연구에서는 막의 재료로 열적, 화학적 성질이 우수한 폴리이미드 막에 대해 PVP가 첨가되었을 때의 영향을 살펴보았는데, 특히 macrovoid가 없고 높은 투과도를 얻을 수 있는 조겅의 용액에 PVP를 첨가하여 막을 제조할 경우 나타나는 막의 구조 및 투과 특성의 변화를 중점적으로 관찰하였다.

• Journal of the Korean Ceramic Society
• /
• v.38 no.11
• /
• pp.1060-1066
• /
• 2001

Water-based alumina tapes for application of all-ceramic crowns were fabricated using PVP as binder that is biocompatible, highly soluble in solvents, and no residue leftafter firing. Tensile strength of alumina tapes was governed by binder/(binder+plasticizer)ratio. On the other hand, linear shrinkage and density were determined by alumina/(alumina+organic) ratio. Composite for all-ceramic crowns, prepared by infiltration of a glass into sintered porous alumina, showed high flexural strength which increased with increasing sintered density.

• Archives of Pharmacal Research
• /
• v.2 no.1
• /
• pp.35-47
• /
• 1979

In order to increase the dissolution rate of furosemide(4-choro-N-furfury1-5-sulfamoy1 anthranilic acid_, various ratio coprecipitates with water-soluble polymers, such as polyvinylpyrrolidone and polythylene glycol, of different molecular weight, were prepared and quantitatively studied by comparing their dissolution characteristics of furosemide at powder state and at nondisintegrating disk state containing constant surface area at various temperatures and rotating velocities. The dissolution characteristics of furosemide from pure furosemide disks and 1:2(w/w) furosemide-PVP coprecipitate disks were in accordance with Noyes-Nernst equation and the rate constant of dissolution was proportional to the square root of rotating velocity of the disks. The intrinsic rate of dissoluton at 150 rpm, 37.deg.C was $2.21{\times}10^{-7}$ for the PVP 10, 000 COPRECIPITATE, $1.64{\times}10^{-7}$ for the PVP 40, 000 coprecipitate, and$ 1.44 {\times} 10^{-7}$for the PVP 360, 000 corprecipitate, while the rate was $1.27{\times}10^{-8}M/cm^{2} min$ for pure furosemide, repectively. The activation energy of dissolution was about 17, 000 for furosemide and about 7, 300 cal/mole for the 1:2 furosemide PVP 40, 000 coprecipitate, respectively.