• Restorative Dentistry and Endodontics
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• 제6권1호
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• pp.51-62
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• 1980

A Scanning Electron Microscope study was conducted to compare the effectiveness of mechanical preparation of the root canal in conjunction with a few number of canal irrigants that have been widely used for canal treatment. The irrigants used in this study were 5% sodium hypochlorite, 3% hydrogen peroxide, 15% EDTA, and 30% hydrochloric acid. The root canals of 84 freshly extracted teeth with single or multi root were conventionally prepared with Hedstroem files. 78 canals were irrigated with normal saline solution following each instrument number and 6 canals were prepared without irrigation. After instrumentation 72 canals were flushed with various irrigants for predetermined length of time as shown on the Table 1. Additional 20 teeth were kept uninstrumented and five of them were immersed in 15% EDTA for 5 minutes, five in 5% sodium hypochlorite for 5 minutes, five in 3% hydrogen peroxide for 20 minutes, and the last five were only rinsed with saline solution. The SEM examination revealed as follows: 1. The canal wall cannot be thoroughly prepared by means of files. 2. No typical structural changes occured on instrumented dentin surface by saline solution, 3% $H_2O_2$, 5% NaOCl, within 5 minutes. 3. 5% NaOCl Solution showed excellent solvent effect to organic substances in uninstrumented canal within 5 minutes and 15% EDTA and 3% $H_2O_2$ showed unsignificant changes. 4. 15% EDTA and 30% HCl dissolved calcified debris and dentin chips that obturated the dentinal tubules and showed patent orifices. 5. 15% EDTA affected on peritubular dentin more readily and showed concavity around dentinal tubules.

• 분석과학
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• 제6권3호
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• pp.261-265
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• 1993

새로운 DBPDA이온교체, {(4,5):(13,14)-dibenzo-6, 9, 12-trioxa-3, 15, 21-triazabicyclo [15.3.1] heneicosa-1(21), 17, 19-triene-2, 16-dione : DBPDA 이온교환체}의 이온교환용량은 4.2meq/g이었다. 그리고 이 이온교환체에 대한 알칼리 및 알칼리 토금속 이온들의 분배계수를 여러 농도의 염산용액 중에서 측정하였다. 또한 DBPDA 이온교환체를 사용하여 알칼리 및 알칼리 토금속 이온들을 이온교환 컬럼 크로마토그라피로 분리하였다. 이러한 결과로부터 알칼리 및 알칼리 토금속 이온들의 분배계수에 미치는 용액의 pH와 금속 이온들의 이온반경 효과를 고찰하였다.

• Asian-Australasian Journal of Animal Sciences
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• 제15권5호
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• pp.682-686
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• 2002

Ten growing male buffalo calves (aged 6-8 months, average body weight $88.2{\pm}0.57$ kg were divided randomly into two groups. Animals in group I were fed on concentrate mixture A (CP 20.2%, TDN 77.4%) and urea- ammoniated wheat straw (UAWS) while the animals in group II were fed on concentrate mixture B (CP 17.9%, TDN 77.6%) and HCl plus urea treated wheat straw (HCl UAWS) to meet their nutrient requirement for 500 g gain/d as per Kearl (1982). This feeding practice lasted for 120 days, during which fortnightly body weight were recorded to assess their growth rate. A metabolism trial was conducted after 90 days of experimental feeding to compare the digestibility of nutrients, their balance, plane of nutrition and relative cost of feeding in two groups of animals. Results revealed a significant increase in the CP content of ammoniated wheat straw due to addition of HCl viz 12.1% from 7.5%. There was a decrease in the intake of DM (p<0.05), OM (p<0.05), EE (p<0.05), NDF (p<0.01), ADF (p<0.01), cellulose (p<0.01) and hemicellulose (p<0.01) in group II as compared to group I. The digestibility (%) of DM, OM and CP was significantly (p<0.01) more in group II, whereas the digestibility (%) was significantly more for NDF (p<0.05) and hemicellulose (p<0.01) in group I than group II. There was no significant difference in the N, Ca and P balance in two groups. Intake of total DM (g/d) or (g/kg $W^{0.75}$) was significantly (p<0.01) more in group I as compared to group II, whereas the intake of DCP and TDN (g/d or g/kg $W^{0.75}$) was alike in two groups. The total body weight gain (kg), average daily gain (g/d) and feed conversion efficiency were significantly (p<0.01) more in UAWS fed group as compared to HCl UAWS fed group. Feeding cost (Rs./kg. weight gain) was significantly (p<0.05) more in group II as compared to group I. It is concluded that HCl UAWS is not suitable for the feeding of growing buffalo calves as it reduced the growth rate in comparison to UAWS fed buffalo calves.

• 자원리싸이클링
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• 제27권3호
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• pp.8-15
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• 2018

Nd-Fe-B 폐 영구자석으로부터 회수한 염화희토류용액을 PC88A에 의한 경희토류(Pr, Nd)/중희토류(Tb, Dy) 분리정제에 대한 용매추출 연구를 진행하였다. 회분식 실험 단계에서 추출제(PC88A) 농도 0.5 M, 추출 후 평형 pH는 0.8~1.0(feed의 초기 pH 1.3), 세정액(HCl)의 농도는 0.1 M, 탈거액(HCl)의 농도는 2 M 이상일 때 분리 효율이 좋은 것을 확인하였다. 이 결과값을 혼합침강조에 적용하여 초기 조건에서 운용 조건을 변화시키면서 180시간 운용하여 3N급의 경희토류(Pr, Nd)/중희토류(Tb, Dy)금속 이온으로 분리정제 후 회수하였다.

• 자원리싸이클링
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• 제15권6호
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• pp.33-40
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• 2006

폐 PCBs중 구리의 효율적이고 친환경적인 회수기술을 개발하려는 목적으로, 염산 용액 내에서 전해 생성된 염소를 이용하여 구리의 침출거동에 관한 연구를 수행하였다. 염산농도 1M, 교반속도 400 rpm, 용액온도 $25^{\circ}C$, 전류밀도 $10mA/cm^2$에서 전해 생성된 염소의 반응초기(구리이온 농도<3.6g/L) 침출반응 이용효율은 거의 100% 이었다 침출의 진행으로 용액 내 구리 이온의 농도가 3.6g/L에 도달하면 전기화학적 산화종이 $Cl^-$에서 침출반응으로부터 생성된 $Cu^+$ 이온으로 바뀌어 전극 전위의 급격한 감소가 관찰되었다. 또한 1M염산 침출 용액 내 구리 이온의 농도가 CuCl의 용해도 한계인 5.2g/L에 도달하면 침출속도가 초기침출속도보다 약 0.5배정도 감소하였다. CuCl의 용해도 한계가 높은 $Cl^-$의 농도가 3M인 조건에서는 이러한 침출속도의 감소가 일어나지 않았으며 이는 구리 표면에 $CuCl_{(s)}$층 생성이 침출반응에 큰 영향을 주는 것을 의미한다.

• Journal of Chest Surgery
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• 제23권1호
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• pp.90-94
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• 1990

Between Dec. 1958 and Oct. 1989, we had been experienced 14 cases of the esophageal corrosion carcinoma among 562 cases of corrosive esophageal stricture, which incidence was revealed 5.6 % of total esophageal carcinoma cases and 2.5 9o of total benign esophageal stricture cases. The age distribution was from 15 to 64 years, and the mean age was 45.6 years. Ten of the patients were women. The caustic agents were lye in 12 patients and hydrochloric acid in 2 patients. The latent time from injury to the development of carcinoma was from 12 years to 45 years, and the mean latent time was 29 years. In majority of cases, the developing site of carcinoma was just or just above the benign stricture portion of the esophagus. Corrective surgery were made in seven cases; three cases were made esophagectomy and esophagogastrostomy, and the other four cases were made esophagectomy and colon interposition. Palliative surgery including feeding gastrostomy were made in seven cases. All cases had a longstanding history of difficult oral swallowing especially at the site of stricture. We think chronic food irritations of stricture portion of the esophagus induced the development of corrosion carcinoma. In conclusion, we had to suspect possibility of carcinoma in patient with long standing history of benign esophageal stricture. So we recommended preoperative esophagoscopic biopsy in such cases.

• 대한소아치과학회지
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• 제24권3호
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• pp.511-517
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• 1997

Tooth discoloration detracts from one's appearance and influences self-image and it is particularly true in children. Therefore, pediatric dentists are required to treat tooth discoloration manifested in children for the normal development of their psycosocial health. Three treatment modalities are currently availabler for the removal of a variety of intrinsic stains from vital teeth. These are enamel microabrasion technique using hydrochloric acid, office bleaching and home bleaching technique with carbamide. Microabrasion technique has several advantages over bleaching in that it is easy to accomplish and does not require multiple office visits or the expensive instruments and the color change seems to be permanent after treatment. The process relies on decalcification, a softening with HCl and then removal of the enamel containing the stain with rubbing. Due to the mechanism of stain removal, this method is indicated for the removal of superficial enamel stains or disc oloration only. We report four successfully treated cases by enamel microabrasion using 15% HCl and pumice. Entire clinical steps are described in detail with some discussions on the outcome.

• The Korean Journal of Ceramics
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• 제3권1호
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• pp.52-56
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• 1997

The Pt doped $TiO_2$ composite membranes were prepared by the sol-gel process. The Pt doped titania sol was peptized with hydrochloric acid in the pH range of 1.23 to 1.32 at 5$0^{\circ}C$. The average particle size of the Pt doped titania sol was shown to be below 15nm and well dispersed in the solution. XPS show the Pt elements continuous and homogeneous dispersed in the $TiO_2$ membrane. The mean particle size of the Pt doped $TiO_2$ composite membrane has smaller than that of the undoped $TiO_2$ composite membrane. The average pore size of the Pt doped $TiO_2$ composite membrane was increased from 58 to 193 $\AA$ with firing temperature changed from 550 to 85$0^{\circ}C$. It was observed that the Pt doped $TiO_2$ composite membranes showed crack-free and homogeneous microstructue as well as narrow particle size distribution up to above 75$0^{\circ}C$.

• 대한화학회지
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• 제54권4호
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• pp.414-418
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• 2010

Ethyl 1-aminotetrazole-5-carboxylate (1)를 hydrazine hydrate와 반응시켜서 대응하는aminohydrazide 2를 합성한 후에, 화합물 2를carbon disulfide와 반응시켜서 1,3,4-oxadiazole-5-thiol structure 3을 합성하였다. 얻어진 화합물 3을 either chloroacetone 또는 ethyl chloroacetate와 반응시켜서S-acyl 1,3,4-oxadiazole 유도체인 4 와 5를 합성하였으며, 또한 hydrazine hydrate와 반응시켜서 4-amino-1,2,4-triazole-5-thiol 유도체인 6을 합성하였으며, 화합물 6을 glacial acetic acid와 반응시켜서 6-methyl-1,3,4-triazolo[3,4-b]-1,3,4-thiadiazole (7)을 합성하였다. 한편, 알려진 방법에 따라서, 화합물 1로부터 tetrazolo[5,1-f]-1,2,4-triazine 9을 얻은 다음에, 화합물 9를 carbon disulfide와 반응시켜서 8-thione 유도체인 10을 합성한 후에, 대응하는 화합물 11, 12 및 13을 합성하였다. 얻어진 화합물13을 이용하여1,2,4-triazolo[4,3-d]tetrazolo[5,1-f]-1,2,4-triazines 14와 15를 합성하였다. 새롭게 합성한 화합물들의 화학구조를 확인하였으며, 합성한 화합물들에 대한 항균 활성시험을 수행하였다.

• 농업과학연구
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• 제10권1호
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• pp.135-145
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• 1983

당근 주우스 개발(開發)을 위(爲)한 기초자료(基礎資料)를 얻고자 당근의 blanching 조건(條件), 산천리(酸處理), alkali 처리(處理) 및 살균처리(殺菌處理)가 당근 주우스의 품질(品質)에 미치는 영향을 검토(檢討)하여 다음과 같은 결론(結論)을 얻었다. 1. 당근을 $90{\sim}100^{\circ}C$의 열탕(熱湯) 중(中)에서 15~5분간(分間) blanching하였을 때 $100^{\circ}C$에서 5분간(分間) 처리(處理)한 것이 당근 주우스의 당도(糖度), amino-N, suspended solid, 광투과도(光透過度) 및 수율면(收率面)에서 가장 우수(優秀)하였다. 2. 당근을 0.05N의 구연산, 초산용액(醋酸溶液) 및 0.03N의 염산(鹽酸) 용액(溶液) 중(中)에서 blanching하였을 때 초산용액처리(醋酸溶液處理)가 주우스의 suspended solid, 광투과도(光透過度), 점도(粘度) 및 수율면(收率面)에서 유리(有利)하였다. 3. 당근 주우스의 제조공정(製造工程) 중(中)에 있어서의 변색(變色)은 blanching 조건(條件)에 의(依)해서 좌우(左右)되었으며 살균공정(殺菌工程) 중(中)에는 거의 변색(變色)되지 않았다. 4. 당근 주우스 제조공정(製造工程) 중(中)에 있어서의 ${\beta}$-carotene의 변화(變化)는 심(甚)하지 않았으며 당근을 파쇄(破碎)하여 $115^{\circ}C$에서 30분간(分間) 살균(殺菌)하였을 때에도 80%내외(內外)의 ${\beta}$-carotene이 잔존(殘存)하였다. 5. 희초산용액(稀醋酸溶液) 중(中)에서 blanching한 후(後) 착즙(搾汁)한 당근 주우스에 alkali를 첨가(添加)하여 중화(中和)한 후(後) 살균(殺菌)하였을 때에는 화학성분(化學成分)의 변화(變化)는 거의 인정(認定)되지 않았으나 변색(變色)이 뚜렸하였고 광투과도(光透過度)가 증대(增大)되어 품질(品質)을 저하(低下)시키는 원인(原因)이 되었다. 6. 무처리(無處理) 당근 주우스 중(中)의 당류(糖類)의 조성(組成)은 ribose 8.51%, fructose 10.15%. glucose 12.25%, sucrose 49.53% 및 oligosaccharide 19.56%로 구성(構成)되어 있었으며 비등수 중(中)에서 blanching하였을 때에는 이당류(二糖類) 이하(以下)의 당(糖)의 함량비(含量比)가 약간(若干) 감소(減少)되었으나 oligosaccharide는 약간(若干) 증가(增加)하였고 산액중(酸液中)에서 blanching하거나 이를 더욱 중화(中和), 살균(殺菌)하였을 때는 ribose와 sucrose의 함량비(含量比)가 현저(顯著)히 증가(增加)하였으며 fructose와 glucose도 약간(若干) 증가(增加)하는 경향(傾向)을 나타내었다. 7. 당근 주우스 중(中)에서 19가지의 유리(遊離) amino산(酸)이 동정(同定)되었고 주요 amino산(酸)은 threonine + aspargine, alanine, serine + glutamine, aspartic-acid, arginine 및 glutamic acid 등(等)이었다.