• 대한소아치과학회지
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• 제33권4호
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• pp.633-642
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• 2006

본 연구는 레진 표면을 연마한 후 레진 표면 강화재를 도포한 것이 표면 처리하지 않은 군에 비해 칫솔질 마모시 표면 특성 즉, 표면 조도, 표면 자유 에너지, 마모율 등의 변화가 있는지 알아 보기 위해 시행하여 다음과 같은 결과를 얻었다(p=0.05). 1. 평균 조도는 Biscover < Forify < Polishing군 순이었다. 마모 전과 6개월에서는 모든 군에서 유의한 차이를 보였고, 1개월, 2개월, 3개월에서는 Polishing군과 Fortify군, Polishing군과 Biscover군에서 유의한 차이를 보였다. 2. 표면 자유 에너지는 마모 전은 Polishing군과 Biscover군, Fortify군과 Biscover군에서 유의한 차이를 보였고(Biscover < Fortify < Polishing), 1개월에서는 Polishing군과 Fortify군에서 유의한 차이를 보였으며, 2개월에서는 각 군간 유의한 차이를 보이지 않았다. 3개월에서는 Fortify군과 Biscover군에서 유의차를 보였고, 6개월에서는 Polishing군과 Fortify군, Fortify군과 Biscover군에서 유의한 차이를 보였다 (Fortify < Polishing < Biscover). 3. 마모율은 1개월에서 모든 군에서 유의차를 보였으며, 2개월에서는 군 간 유의차가 없었고, 3개월과 $4{\sim}6$개월 평균 마모율은 Polishing군과 Biscover군, Fortify군과 Biscover군에서 유의한 차이를 보였다. Fortify와 Biscover의 두께를 고려했을 때, Fortify는 2개월 내에, Biscover는 6개월 정도에 거의 소실되었다.

• Journal of Radiation Protection and Research
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• 제20권4호
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• pp.237-243
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• 1995

파라핀 왁스를 사용하여 건조된 농축폐액을 고화시킬 경우, 방사선적 가수분해에 의해 발생할 가능성이 있는 수소가스의 발생량을 추정하여 보았다 분석결과에 의하면, 코발트 60의 방사선 에너지에 의해 방사선적 가수분해가 주로 발생함을 알 수 있다. 200리터 드럼중 120 리터가 파라핀으로 채워졌다고 가정할 때 수소가스 발생은 초기에 $4.4{\times}10^2cm^3yr^1$이고 100년이 경과한 후는 $7.2cm^3yr^1$로 줄어든다. 수소에 의한 발화점을 25년이 경과한 후 도발할 가능성이 있으나, 폭발한계에는 1000년 이내에 도달할 가능성이 없다. 안전성 관련 주요 한계점에 도달하는 시기는 드럼내 파라핀 왁스의 채움 정도에 매우 민감하게 영향을 받는다 드럼내 공간의 감소시, 발화점에 도달 시간이 줄어듬을 알 수 있다.

• 치위생과학회지
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• 제12권5호
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• pp.459-468
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• 2012

본 연구는 2011년 6월 10일~11일까지 유아기의 비만과 구강건강과의 관계에 대하여 조사 분석하였다. 연구대상은 강원도에 위치한 K어린이집의 유아 90명을 대상으로 설문조사와 구강검사를 실시하였다. 수집된 자료는 SPSS WIN 15.0프로그램을 이용하여 분석한 결과 다음과 같은 결론을 얻었다. 1. 유치우식경험자율은 56.7%이었으며, 유치우식유병자율은 42.2%로 나타났다. 2. 일반적 특성에 따른 유치우식경험율을 조사한 결과 연령이 증가할수록 유치우식경험율이 높게 나타났다. 3. 성장과 비만 정도에 따른 유치우식경험율을 조사한 결과, 신장이 100~110 cm, 체중이 25 kg 이상인 유아가 다른 유아보다 유치우식경험율이 높게 나타났으며, 110~115cm인 유아가 다른 유아보다 유치우식유병율이 높게 나타났다. 4. 일반적 특성에 따른 우식경험유치(면)수를 조사한 결과, 연령이 많은 유아일수록 우식경험유치수와 우식경험유치면수가 높게 나타났다. 5. 성장과 비만 정도에 따른 우식경험유치(면)수를 조사한 결과, 체중이 높은 유아일수록 우식경험유치수와 우식경험유치면수가 높게 나타났으며, 과체중인 유아일수록 우식유치수, 충전유치수, 우식경험유치수와 우식유치면수, 우식경험유치면수가 높게 나타났다. 비만과 치아우식증이 관련성이 있는 것으로 나타났으므로, 보육기관에서는 유아들이 올바른 식습관을 익히도록 유아, 부모(보호자), 보육교사를 대상으로 지속적인 구강보건교육을 통하여 효율적인 구강건강관리에 도움을 주어야 할 것이다. 또한 간식 선택에 있어서도 신중을 기해야 할 것으로 사료된다. 학령전기인 유아를 대상으로 체계적으로 구강보건사업을 실시하여 유치뿐만 아니라 영구치도 효율적으로 관리할 수 있도록 구강보건사업의 연계성을 높여야 할 것이다.

• 토지주택연구
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• 제1권1호
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• pp.35-42
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• 2010

하수도관 정비사업 및 정부의 4대강 사업에서 발생되는 준설모래는 대부분 투기 및 매립에 의존하여 처리되고 있다. 이는 준설모래를 적절히 이용하는 관련 재활용 기술의 부족과 기존의 준설모래 생산시스템에서 생산된 준설모래의 높은 흡수율과 미립분 함유량에서 비롯된다. 따라서 본 연구에서는 기존의 준설모래 생산시스템의 문제점을 보완한 최적의 세척선별시스템을 통해, 준설모래 품질개선 성능과 세척선별시스템의 미립분과 유기이물질 제거 성능을 알아보기 위한 연구의 일환으로서, 처리된 준설모래의 기초물성을 평가한 결과, 세척선별시스템을 통해 생산된 준설모래가 흡수율, 0.08 mm체 통과량, 점토덩어리량, 유기이물질 함유량에서 큰 폭의 품질개선효과를 나타냈으며, 본 연구에서 목표로 하는 품질기준인 KS F 2573(콘크리트용 순환골재)과 KS F 2526(콘크리트용 골재) 기준에 모두 만족하는 것으로 나타나 향후 콘크리트용 골재로서의 활용가능성을 확인할 수 있었다.

• 한국학교ㆍ지역보건교육학회지
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• 제2권1호
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• pp.31-40
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• 2001

A study of fluoride effects on teeth of school children was conducted in order to determine the usefulness of fluoride for preventing dental caries. Nine hundred and thirty six(936) elementary school children were selected from Chongju where children drank fluoridated water. Eight hundred and thirty six(836) from Seoul where children applied fluoride topically, and eight hundred and three(803) from Kumi where the children drank non fluoridated water(control). DMFs of school children were compared by the sources of fluoride. This study was conducted from May 1, through June 15, 2000. The results are summarized as follows; 1. The DMF rate of male school children topically applying fluoride was 51.4%, that of female children was 56.1%, and that of both males and females was 54.0%, The DMF rate of male children of control group was 72.4%, that of females was 77.5% and that of both males and females was 74.8%. 2. The DMF rate of male children drinking fluoridated tap water was 56.1%, that of females was 54.1%, and that of both males and females was 55.5%. The rates of control group were 72.4% for males, 77.5% for females and 74.8% for male and female children respectively. 3. The difference of DMF rates between the group of children who drank fluoridated water and applied fluoride topically, and control group was statistically significant. 4. The difference of DMF rates between the children who drank fluoridated water and the children who applied fluoride topically were not statistically significant. 5. The difference of DMFT rates between 5th graders who applied fluoride topically and the 5th graders of control group was not statistically significant. However, the difference of DMFT rates of the 6th graders who applied fluoride topically and the same graders of control group were statistically significant. The difference of DMF rates between 5th and 6th graders who drank fluoridated tap water and the same graders of control group was statistically significant. 6. The difference of DMFT rates between children drinking fluoridated tap water and children applying fluoride topically was statistically significant.

• 한국분말재료학회지
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• 제16권6호
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• pp.431-437
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• 2009

Various inorganic fillers improve the thermal conductivity and physical properties of organic products. Alumina has been used a representative filler in the heat radiation sheet for the heat radiation of electric device. The high filling rate of alumina increases the thermal conductivity and properties of products. We successfully developed the spherical alumina by flame fusion process using the oxygen burner with LPG fuel. In the high temperature flame (2500$\sim$3000$^{\circ}C$) of oxygen burner, sprayed powders were melting and then rotated by carrier gas. This surface melting and rotation process made spherical alumina. Especially effects of chemical composition and particle size of stating materials on the melting behavior of starting materials in the flame and spheroidization ratio were investigated. As a result, spheroidization ratio of boehmite and aluminum hydroxide with endothermic reaction of dehydration process was lower than that of the sintered alumina without dehydration reaction.

• 한국축산식품학회지
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• 제40권1호
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• pp.21-33
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• 2020

This study aimed to determine the current prevalence, serovar distribution and antimicrobial resistance rate and patterns of nontyphoid Salmonella (NTS) in slaughter sheep and their edible offal. While filling the gap of up to date related information in Turkey, data presented is also of significance since contamination of ovine meat, its products and offal with this pathogen is threat to public health due to their considerably high consumption rates in our country. Current NTS carriage in 200 apparently healthy slaughter sheep by ISO 6579:2002, 6579:2002/A1:2007 standard bacteriology (ISO) was 5% (10/200) (4 fecal content - 2%, 3 mesenterial lymph node - 1.5%, 3 kidney - 1.5%) out of 1,400 samples (0.7%), with no isolation from carcass, liver, gallbladder, spleen. Real-time PCR was in substantial agreement to ISO in confirming Salmonella-suspect isolates (Relative Trueness: 93.6%). S. Newport (40%) was the predominant serovar, followed by the second prevalent serovars as S. Typhimurium and S. Kentucky (20%), and by S. Umbilo and S. Corvallis (10%). Four and 6 out of 10 NTS isolates were susceptible (40%) and resistant (60%) to 18 antimicrobials, respectively. S. Typhimurium isolates were multidrug resistant (MDR) to tigecycline and sulphamethoxazole/trimethoprim, with one also resistant to cefepime. S. Corvallis was MDR to ampicillin, ciprofloxacin, norfloxacin and pefloxacin. The predominance of S. Newport and first isolation of S. Corvallis in sheep in the world; first time isolations of Newport, Kentucky, Corvallis, Umbilo serovars from sheep in Turkey; and high antimicrobial resistance rates obtained in majority of the isolates highlights study findings.

• 분석과학
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• 제10권3호
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• pp.179-186
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• 1997

본 연구는 식물체 중 게르마늄을 분석할 때 기존의 방법보다 분석효율이 높고 간편하여 분해시간이 짧게 걸리는 방법을 찾고자 실험을 수행하였다. 시료 분해시 분해액은 $HNO_3+HClO_4+H_2SO_4$의 혼합산을 10 : 4 : 1(v/v)의 비율로 혼합 사용하였을 때 분해 소요 일수는 4~5일이었고, 회수율은 98% 이상이었다. 분해 후 최종 일정 부피로 맞추어 주기 위한 용액은 0.1M acetic acid-sodium acetate가 좋았으며, 아르곤 연료를 사용한 탄소봉원자화기부착 원자흡광분광광도계의 검출 한계는 0.02ppm이었다. 이와 같은 결과들은 식물체 중 게르마늄 분석에 있어서 전술한 실험 목적에 부합되는 결과였다.

• 말소리와 음성과학
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• 제1권2호
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• pp.51-59
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• 2009

This study was designed to investigate the effects of neonatal hearing screening program (NHSP) information on parental satisfaction with the Parent Satisfaction Questionnaire with Neonatal Hearing Screening Program (PSQ-NHSP) by Mazlan et al. (2006). The PSQ-NHSP consisted of four aspects including: information, personnel in charge of the hearing test, appointment activity, and overall satisfaction in the neonatal hearing screening program. A total of 106 parents (50 in the experimental group and 56 in the control group) participated in this study in one general hospital and two delivery clinics. The fifty parents in the experimental group received information and counseling with educational materials before filling out the PSQ-NHSP, but the fifty-six parents in the control group did not receive any counseling or education materials before completing the PSQ-NHSP. The PSQ-NHSP demonstrated excellent internal consistency reliability (${\sigma}=0.914$). The results of the study were as follows. First, the overall satisfaction ($3.77{\pm}0.81$) and personnel in charge of hearing test ($3.52{\pm}0.79$) aspects showed higher rates of satisfaction than the appointment activity aspect ($3.51{\pm}0.80$) for total subjects. Second, the overall parental satisfaction rate of the experimental group ($4.15{\pm}0.50$) was significantly higher than that of the control group ($3.09{\pm}0.53$) in all items. Lastly, thirty-two participants (30%) made at least one comment in response to the open-set items. A total of 29 comments were related to satisfaction with participating in the NHSP and II comments were related to dissatisfaction. In conclusion, to improve parental satisfaction it is important to provide parents with education and information about the NHSP before the test. In addition, PSQ-NHSP was found to be a useful instrument for identifying the benefits and shortfalls of the NHSP.

• International Journal of Fluid Machinery and Systems
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• 제10권2호
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• pp.119-137
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• 2017

Although the stall stagnation phenomena have often been experienced in site and also analytically in numerical experiments in surges in systems of compressors and flow paths, the fundamental causes have not been identified yet. In order to clarify the situations, behaviours of infinitesimal disturbance waves superposed on a main flow were studied in a simplified one-dimensional flow model. A ratio of the amplifying rate of the system instability to the characteristic slope of the compressor element was surveyed as the instability enhancement factor. Numerical calculations have shown the following tendency of the factor. In the situation where both the sectional area ratio and the length ratio of the delivery flow-path to the suction duct are sufficiently large, the enhancement factors are greater in magnitude, which means occurrence of ordinary deep surges. However, in the situation where the area ratio and/or the length ratio is relatively smaller, the enhancement factor tends to lessen significantly, which situation tends to suppress deep surges for the same value of the characteristic slope. It could result in the stall stagnation condition. In the domain of area ratio vs. length ratio of the delivery duct to the suction duct, contour-lines of the enhancement factor behave qualitatively similar to those of the stall stagnation boundaries of a fan analytically obtained, suggesting that a certain range of the enhancement factor values could specify the stagnation occurrence. The significant decreases in the factors are observed to accompany appearances of phase lags and travelling waves in the wave motions, which macroscopically suggests breaking down of the complete surge actions of filling and emptying of the air in the delivery duct. The strength of the action is deeply related with acoustic interferences and is evaluated in terms of the volume-modified reduced resonance frequency proposed by the author. These observations have shown the fundamental cause and the sequence of the stall stagnation in principle.