• Restorative Dentistry and Endodontics
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• 제8권1호
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• pp.107-113
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• 1982

The purpose of this study was to observe the tensile strength of composite resins to etched dentin surface with the various methods of placing bonding agent before composite resin or placing composite resin alone. Recently extracted 60 maxillary incisors were chosen. These were divided into 6 groups: Group I : Immediate Silar adaptation to the etched dentin surface with 37% phosphoric acid for 60 seconds without bonding agent. Group II : Immediate Silar adaptation to the etched dentin surface with 37% phosphoric acid for 60 seconds with bonding agent. Group III : Silar adaptation to the etched dentin surface with 37% phosphoric acid for 60 seconds after 5 minutes of bonding agent. Group IV : Immediate Enamelite adaptation to the etched dentin surfaces with 50% phosphoric acid for 120 seconds without bonding agent. Group V : Immediate Enamelite adaptation to the etched dentin surface with 50% phosphoric acid for 120 second s with bonding again. Group VI : Enamelite adaptation to the etched dentin surface with 50% phosphoric acid for 120 seconds after 5 minutes of bonding agent. All specimens were immersed in water at $37^{\circ}C$ for 24 hours before testing. The results were as follows: 1. The tensile strength of powder/liquid composite resin system was higher than that of pastel paste composite resin system. 2. The tensile strength of the composite resin group II, III, V, & VI with bonding agent was higher than that of the composite resin group I & IV without bonding agent. 3. The tensile strength of the composite resin group III & VI after 5 minutes added to bonding agent was higher than that of the composite resin group II & V immediately added to bonding agent.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2001년도 The 6th International Symposium of East Asian Resources Recycling Technology
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• pp.478-481
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• 2001

The spent petrochemical catalyst used in the manufacturing process of terephthalic-acid contains valuable metals such as cobalt and manganese. To recover these metals, sulfuric acid leaching was performed with hydrogen peroxide as a reducing agent. Low extractions of Mn, Co and Fe were obtained by sulfuric acid leaching without reducing agent. With adding hydrogen peroxide as a reducing agent, the high extraction of these metals could be obtained. Different from general leaching experiment, the extraction rates of metal components were decreased with increasing reaction temperature in this case. Under the optimum condition, the extraction rates of Mn, Co and Fe were 93.0%, 87.0% and 100% respectively.

• 폴리머
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• 제24권6호
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• pp.770-776
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• 2000

비반응성 커플링제기 도입에 따라 talc가 충전된 폴리프로필렌의 기계적, 열적 물성에 미치는 영향을 살펴보았다. 커플링제로서 stearic acid와 이와 화학적으로 유사한 구조를 가지는 oleic acid를 사용하였으며 커플링제의 종류 및 농도에 따라 talc로 충전된 폴리프로필렌의 인장강도, 굴곡강도, 충격강도 및 열적안정성, 용융전이점 등을 측정, 분석하였다. 인장강도와 굴곡강도는 커플링제의 종류에 관계없이 커플링제의 도입에 따라 증가하였으며, talc 대비 3 wt%의 농도에서 최대값을 보였다. 인장강도와 굴곡강도에서는 oleic acid로 처리한 시편의 강도가 stearic acid로 처리한 시편의 강도보다 높은 값을 나타내었으나, 충격강도에서는 그 반대의 결과를 나타내었다. 전자주사현미경 (SEM)을 이용하여 각 시편의 모폴로지를 관찰함으로써 이러한 결과에 대한 원인을 유추해 보았다.

• 한국전기전자재료학회논문지
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• 제17권3호
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• pp.272-277
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• 2004

The primary aim of this study is to investigate new semi-abrasive free slurry including acid colloidal silica and hydrogen peroxide for copper chemical-mechanical planarization (CMP). In general, slurry for copper CMP consists of colloidal silica as an abrasive, organic acid as a complex-forming agent, hydrogen peroxide as an oxidizing agent, a film forming agent, a pH control agent and several additives. We developed new semi-abrasive free slurry (SAFS) including below 0.5％ acid colloidal silica. We evaluated additives as stabilizers for hydrogen peroxide as well as accelerators in tantalum nitride CMP process. We also estimated dispersion stability and Zeta potential of the acid colloidal silica with additives. The extent of enhancement in tantalum nitride CMP was verified through anelectrochemical test. This approach may be useful for the application of single and first step copper CMP slurry with one package system.

• 약학회지
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• 제41권4호
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• pp.480-483
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• 1997

The efficient synthesis of p-(acetylamino)phenylacetic acid(7), a antirheumatic agent, is reported. Methyl phenylacetate(3) was prepared from Friedel- Crafts reaction of benzene with methyl ${\alpha}$-chloro-${\alpha}$-(methylthio)acetate(1) followed by reductive desulfurization with zinc dust in acetic acid. Compound(7) was obtained from 3 by a sequence of nitration, reduction, N-acylation, and hydrolysis.

• 반도체디스플레이기술학회지
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• 제13권3호
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• pp.13-19
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• 2014

Phosphoric acid was used as etching agent instead of conventional peroxide - based chemicals for forming pattern of ultra definition display. Etchant was synthesized by mixing etching agent, oxidation agent, buffer solution, and additive into solvent, deionized water. Thicknesses of copper, main metal of ultra definition display, for etching, were 10,000 and $30,000{{\AA}}$. Etch stop of good low skew for proper pattern formation has been occurred at the content ratio of phosphoric acid 60 - 64%, nitric acid 4 - 5%, additive(potassium acetate) 1 - 3%. Buffer solution(acetic acid) decreased the metal contact angle $63.07^{\circ}$ to $42.49^{\circ}$ for benefiting pattern formation. Content variations on four components (phosphoric acid, nitric acid, acetic acid, potassium acetic acid) of the etchant with storage time were within 3 wt% after 24 hrs of etching work.

• 펄프종이기술
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• 제47권3호
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• pp.18-23
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• 2015

In this study, the effects of cationic fatty acid bulky promotor on the properties of BCTMP (bleached chemithermomechnical pulp) handsheet including bulk and strength were elucidated. As results, it was observed that the bulk of BCTMP handsheet increased with the increases of the concentration of cationic fatty acid bulky agent, while mechanical properties such as tensile strength and burst strength decreased. The opacity of BCTMP handsheet also increased with the increases of the concentration of cationic fatty acid bulky agent, while brightness was almost not changed. The effectiveness of bulky agent with SwBCTMP (softwood) was higher than that with HwBCTMP (hardwood). Compared with previous research on the effect of bulky agent on BKP handsheet, the bulk increase of BCTMP handsheet was greater compared to that of BKP handsheet. However, the reduction of mechanical property in BCTMP handsheet was lower than that of BKP handsheet.

• Macromolecular Research
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• 제10권2호
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• pp.127-134
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• 2002

Microporous polypropylene hollow fiber membrane was fabricated from isotactic polypropylene-soybean oil system by melt spinning process. Addition of nucleating agent accelerated the crystallization rate and elevated the crystallization temperature. Nucleating agent increased the number of nuclei and spherulites, which offered more inter-spherulitic amorphous sites for stretching. Benzoic acid, adipic acid, and dibenzylidene sorbitol were selected as nucleating agents, and their characteristics and effects were investigated by thermal and optical analyses. Spherulite growth and micropore formation characteristics were correlated with the kind of nucleating agent. Benzoic acid and adipic acid showed the remarkable nucleating effect, while dibenzylidene sorbitol was less effective than those. Nucleating agents also helped the sample have uniform microporous structure. Increase of nucleating agent composition enhanced the nucleation effect to some extent. Nucleating agents played very important roles in enhancing the membrane porosity and water flux.

• Transactions on Electrical and Electronic Materials
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• 제4권2호
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• pp.1-4
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• 2003

The purpose of this study was to investigate the characteristics of slurry including phosphoric acid for chemical-mechanical planarization of copper and tantalum nitride. In general, the slurry for copper CMP consists of alumina or colloidal silica as an abrasive, organic acid as a complexing agent, an oxidizing agent, a film forming agent, a pH control agent and additives. Hydrogen peroxide (H$_2$O$_2$) is the material that is used as an oxidizing agent in copper CMP. But, the hydrogen peroxide needs some stabilizers to prevent decomposition. We evaluated phosphoric acid (H$_3$PO$_4$) as a stabilizer of the hydrogen peroxide as well as an accelerator of the tantalum nitride CMP process. We also estimated dispersion stability and zeta potential of the abrasive with the contents of phosphoric acid. An acceleration of the tantalum nitride CMP was verified through the electrochemical test. This approach may be useful for the development of the 2$\^$nd/ step copper CMP slurry and hydrogen peroxide stability.

• Journal of Microbiology and Biotechnology
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• 제15권3호
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• pp.510-518
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• 2005

In this study, we investigated whether PLGA microspheres in combination with hyaluronic acid (HA) gel have appropriate properties as a bulking agent for urologic injection therapies and whether the implantation of PLGA microspheres and HA gel induces angiogenesis in the newly formed tissues. In order to investigate whether this bulking agent is injectable, this material was injected through 24-gauge needles into the subcutaneous dorsum of the mouse. The bulking agent was easily injected without needle obstruction. Histological analyses of the hybrid tissues at 2 weeks showed that host cells at the surrounding tissues migrated into the spaces between the implanted PLGA microspheres and formed tissue-like structures. An inflammatory response to the implants was mild at 2 weeks and diminished at 8 weeks. Importantly, extensive ingrowth of blood vessels was observed in the hybrid tissues formed by the injection of PLGA microspheres and HA, whereas blood vessels rarely formed in the hybrid tissues formed by the injection of PLGA microspheres only. The implant volume was conserved for almost the entire implantation period. Histological analyses of the distant organs of the bulking agent-implanted animals, such as the lungs, liver, heart, brain, kidney, and spleen, showed no evidence of the injected microsphere migration. These results show that PLGA microspheres in combination with HA possess the appropriate characteristics for a bulking agent for urologic injection therapies and induce extensive blood vessel formation in the hybrid tissues.