• Journal of the Korean Wood Science and Technology
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• 제25권4호
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• pp.45-50
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• 1997

This research was studied for dissolving pulp preparation as the raw material of viscose rayon from woody biomass by solvolysis pretreatment. In the change of pulp characteristic after solvolysis pretreatment, the following results were obtained. In the case of solvolysis pretreatment, we have obtained pulp that high purity cellulose, and degree of polymerization was inclined to decrease less than 440 on the phosphoric acid as catalyst. Comparing phosphoric acid and formic acid as catalyst in the solvolysis pretreatment, using on formic acid catalyst is superior to phosphoric acid catalyst for making dissolving pulp.

• Restorative Dentistry and Endodontics
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• 제21권1호
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• pp.136-149
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• 1996

The effects of various All-Etching Agents (10% phosphoric acid, 10% maleic acid and 10 % citric acid) and 32 % phosphoric acid and varied etching time were evaluated by observing the morphology of the etched enamel surfaces using Scanning electron microscopy and by measuring the shear bond strength of a composite resin to human enamel. A total of 156 extracted premolar and molar teeth free of irregularities were employed in this study. Specimens for the observation of enamel morphology were divided into 12 groups of 3 teeth each, based on the type of etchant used and application time. After exposure to the etching agent specimens were washed air-dried and then glued to aluminum stubs and coated with a layer of gold for examination in the scanning electron microscope. Specimens for the evaluation of bond strength were divided into 12 groups of 10 teeth each also based on the type of etchant used and application time. After exposure to the etching agent the specimens were washed, air-dried and a thin layer of bonding agent was applied using a brush. Z 100 composite resin was light cured to the surface and stored at $37^{\circ}C$, 100% humidity for 7 days. An Instron Universal Testing Machine was used to apply a shearing force at $90^{\circ}$ angle from the enamel surface. It is concluded from this study that commercial All-etching agents can be used with a 15-second etching without adversely affecting retention of dental resin materials. At the same time, the acid concentration is probably a suitable compromise regarding the acid's function as a dentin demineralizing all-etch conditioning agent. The following results were obtained. 1. Specimens etched with 10 % citric acid showed a random superficial etching pattern which could not be related to prism morphology. 2. Specimens etched with 10 % and 32 % phosphoric acid and 10 % maleic acid showed a type I pattern in which core material was preferentially removed leaving the prism peripheries relatively intact or a type II pattern in which prism peripheries were preferentially removed. This delineation became more distinguished as etching time was increased. 3. All-Etching Agents and 32 % phosphoric acid showed a statistically significant higher shear bond strength at 15 seconds etching time.(p<0.05) 4. 10 % maleic acid and 32 % phosphoric acid exhibited a statistically significant higher shear bond strength than 10 % phosphoric and citric acid at 15 seconds etching time.(p<0.05).

• Applied Biological Chemistry
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• 제29권3호
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• pp.294-303
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• 1986

유기인계(有機燐系) 및 carbamate계(系) 살충제(殺蟲劑)의 처리(處理)로 뇨소(尿素)가 시용(施用)된 토양내(土壞內)의 효소활성(酵素活性) 및 잔류량(殘留量)의 변화(變化), 총세균수(總細菌數)에 미치는 영향(影響)을 규명(糾明)한 결과(結果)는 다음과 같았다. 살충제(殺蟲劑)가 urease와 phosphatase의 활성(活性)에는 dithioposphoric acid, thiophosphoric acid, phosphoric acid, carbamate계(系)의 순(順)으로 저해율(沮害率)이 높았으며, L-glutaminase와 protease의 활성(活性)에는 thiophosphoric acid, dithiophosphoric acid, phosphoric acid, carbamate계(系)의 순(順)으로 저해율(沮害率)이 높았다. 대체적으로 유기인계(有機燐系) 살충제(殺蟲劑)는 처리(處理) 후(後) 56일(日)째까지 약하게나마 저해현상(沮害現象)을 나타낸 반면 carbamate계(系)는 28일(日)째 이후에는 영향(影響)이 거의 없었다. Carbamate계(系) 살충제(殺蟲劑)는 protease와 L-glutaminase의 활성(活性)을 56일(日)째에 약간 증가(增加)시켰다. 뇨소(尿素)의 시용(旅用)으로 인(因)해 살충제(殺蟲劑)의 분해(分解)는 무시용구(無施用區)에 비해서 약간 촉진(促進)되었다. 토양내(土壞內)의 총세균수(總細菌數)는 살충제(殺蟲劑)의 처리(處理)로 초기(初期)에는 대조구(對照區)보다 감소(減少)되었으나 후기(後期)에는 phosphoric acid형(形)과 carbamater계(系)에서는 균수(菌數)가 약간 증가(增加)되었으나 thiophoric, dithiophosphosphoric acid형(形)에서는 계속 저해(沮害)를 받는 것으로 나타났다.

• 한국환경복원기술학회지
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• 제14권6호
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• pp.17-27
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• 2011

Prunus serrulata var. serrulata f. spontanea (E. H. Wilson) C. S. Chang was treated with dried swine excrement at various concentration levels, and their growth reactions and the contents of total kjeldahl nitrogen and total phosphoric acid were analyzed. The result is as follows; 1. When the plants were treated with 0.25% of dried swine excrement, the seed germination rate of Prunus serrulata var. serrulata f. spontanea was higher than that of the control. However, it showed a tendency to decrease when the treatment concentration got higher than 0.25%. 2. The growth rate of species was highest when they were treated with 0.25% of dried swine excrement. It tended to decrease with higher treatment concentration than 0.25%. Significant difference was clear between the control and the experimental plants of Prunus serrulata var. serrulata f. spontanea. 3. The contents of nitrogen and phosphoric acid in Prunus serrulata var. serrulata f. spontanea also got higher as the concentration of dried swine excrement increased. However, the content of total kjeldahl nitrogen was highest in the leaves, and followed by the roots and stems. In contrast, the content of total phosphoric acid were highest in the roots, and followed by the leaves and stems. Therefore, stems had the lowest contents of both nitrogen and phosphoric acid. 4. The contents of total kjeldahl nitrogen and total phosphoric acid in the soil were measured before and after the growth experiment of Prunus serrulata var. serrulata f. spontanea treated with dried swine excrement. The contents of nitrogen and phosphoric acid significantly decreased after the experiment. In conclusion, the contents of total kjeldahl nitrogen and total phosphoric acid accumulated in the plants increased as the concentration level of dried swine excrement got higher. The seed germination and plant growth rates were best at 0.25% treatment of dried swine excrement. The treatment of dried swine excrement may bring high effects on increasing the plant growth rate but could damage the plants with higher concentration than they need. Different optimal concentration levels of dried swine excrement for different plants should be found before it is used as fertilizer.

• 한국식품과학회지
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• 제17권2호
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• pp.128-130
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• 1985

미강유의 탈검에 알맞는 탈검제(Degumming agent)를 찾기 위하여 85% 인산과 4%, 8% 및 12% 수산의 탈검효과를 비교하였다. 85% 인산을 미강조유 1kg당 2ml 첨가할 때와 4%의 수산을 조유 1kg당 20ml를 처리할 때 미강조유내의 검물질을 96.6%까지 제거 할 수 있었다. 탈검후 수율은 인산을 이용할 때 61.0%, 수산을 이용할 때 63.6%로 나타났다.

• Restorative Dentistry and Endodontics
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• 제18권2호
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• pp.423-430
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• 1993

The purpose of this study was to investigate the effect of ferric and ferric ions contained in phosphoric acid solution as a pretreatment solution on bonding of MMA/TBBO resin to dentin. Each of 1 % and 3 % ferric chloride. cupric chloride. cupric sulfate. and cupric nitrate was mixed into 10% phosphoric acid solution and pretreated dentin surface of bovine anterior teeth for 30 seconds followed- by water rinse and dry. Tensile bond strength was determined after bonding of pretreated dentin with MMA/TBBO resin by use of brush-on ;technique and storing for 24 hours in 3it distilled water. The amount of cupric ions adsorbed on pretreated dentin surface was detected by Wave-Dispersion X-ray microanalyzer for different groups of each pretreatment solution containing cupric salts. The pretreatment with cupric ions contained in 10% phosphoric acid solution was effective to increase bonding strength of MMA/TBBO resin to dentin but not in case of ferric ions. The pretreatment with 3 % cupric chloride and cupric nitrate both enhanced significant increase in bonding strength compared to the control group of 10% phosphoric acid solution(p<0.05). Cupric ions measured in pretreated dentin surface was higher in 3 % cupric chloride group than in 1% cupric chloride group, but couldn't find distinct relationship from the results of this experiment between the amount of adsorbed cupric ions according to the kind of cupric salts and the bonding strength value.

• 한국세라믹학회지
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• 제52권3호
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• pp.204-208
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• 2015

Synthesis of hydroxyapatite (HA) was attempted through a room-temperature reaction of calcined eggshell with phosphoric acid. Ball-milled, calcined eggshell powder, which has a specific surface area of $31.6m^2/g$, was mixed with various concentrations of phosphoric acid at room temperature. The mixtures showed high reactivity and a vigorous exothermic reaction ; the reacted samples showed both $Ca(OH)_2$ and $CaHPO_4$ crystal phases. After heating at temperatures above $400^{\circ}C$, an HA crystal phase was observed in all samples. The calcined eggshell showed a pure CaO single phase, while the $Ca(OH)_2$ phase was only observed in the wet, ball-milled calcined powder. The degree of formation of the HA crystal phase increased as the phosphoric acid concentration and the heating temperature were increased. A mixture with 50 wt% phosphoric acid concentration showed a well-developed HA crystal phase after heat treatment at $800^{\circ}C$, while the formation of a more intensive amorphous phase was observed in the products of the room-temperature reaction.

• 한국세라믹학회지
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• 제37권1호
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• pp.26-32
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• 2000

Preparation and characteristics of a matrix retaining electrolyte using SiC whisker, PES binder, and NMP(n-methyl-2-pyrrolidone) as a non-volatile solvent for a phosphoric acid fuel cell were investigated. The conditions of binder and plasticizer, and the effects of substituting a volatile solvent by a non-volatile solvent were also studied. The minimum amount of the binder was about 17 wt% for the proper bubble pressure and surrounding SiC whiskers. And the maximum amount of the plasticizer was about 10wt% to be fitted into the polymer chain of the binder. The matrix prepared by using a non-volatile solvent needed longer time to dry, and its pore size was smaller compared with that of the matrix prepared by using volatile solvent. The small pore size resulted in decrease of the overall pore volume. The ionic conductivity in the condition of the same thickness was decreased due to decrease of phosphoric acid absorbancy. As the internal resistance of the electrolyte increased, the fuel cell performance slightly decreased.

• 한국세라믹학회지
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• 제39권11호
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• pp.1103-1107
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• 2002

생체재료의 일환으로 사용되고 있는 ${\beta}$-TCP(${\beta}$-Tricalcium Phosphate)를 합성하기 위하여 주원료인 칼슘을 화학약품이 아닌 천연재료인 달걀껍질을 이용하여 실험을 하였고, 이를 인산(phosphoric acid)과 혼합하여 ${\beta}$-TCP를 합성하였다. 본 연구에서는 인산의 혼합 량, 하소온도의 변화 그리고 달걀껍질의 출발물질 상태 등의 변수를 두고 실험을 실시하였다. 실험 변수에 따른 결과는 XRD 분석에 의해 결정상을 관찰하고, SEM에 의해 미세구조를 관찰하여 특성분석을 하였다. $900{\circ}$에서 하소한 달걀껍질을 인산과 함께 습식으로 볼 밀링 한 후, 이를 건조시켜 $900{\circ}$에서 1시간 동안 열처리하여 비교적 좁은 입도분포의 ${\beta}$-TCP 분말을 얻을 수 있었다. 차후 합성된 분말의 소결체를 이용하여, 생체 친화성과 뼈 속으로 대체되는 속도 등을 실험할 예정이다.

• 공업화학
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• 제29권3호
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• pp.264-269
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• 2018

Polysulfone (PSf)에 탄소 나노 튜브(CNTs, carbon nano tubes)와 두 가지 추출제, di-(2-ethylhexyl)-phosphoric acid (D2EHPA)와 tributyl phosphate (TBP)를 고정화시킨 PSf/D2EHPA/TBP/CNTs 비드를 제조하였다. 제조한 비드의 특성은 SEM, TGA 및 FTIR로 분석하였다. 제조한 PSF/D2EHPA/TBP/CNTs 비드에 의한 Sr(II)의 제거속도는 유사 2차 속도식에 의해 잘 설명되었으며, Langmuir 등온식으로 구한 Sr(II)의 최대 제거 용량은 5.52 mg/g이었다. 본 연구에서 제조한 PSf/D2EHPA/CNTs 비드에 의한 Sr(II)의 제거효율은 TBP가 첨가되지 않은 PSf/D2EHPA/CNTs 비드에 의한 Sr(II)의 제거효율 보다 크게 향상되는 결과를 나타내었다.