• 한국가축번식학회지
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• 제12권2호
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• pp.120-124
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• 1988

Rat oocyte-cumulus complexes were cultured in verious media in order to induce maturation division in vitro. When the complexes were cultured in mKRB containing estrous rat serum (ERS) and FCS of 5% instead of BSA higher proportions(83.3 and 86.7%) of oocytes matured to metaphase II in 20h compared to control(75%) and t도 maturation rates in mKRB plus FCS were generally higher than those in mKRB plus ERS. Fertilization and early cleavage rates in vitro of the intact oocytes matured in mKRB containing BSA and FCS were generally higher than those of cumulus-removed oocytes and these rates were higher in mKRB containing 5% FCS than those in mKRB containing BSA. These results indicate that maturation rate in vitro was greatly increased by the addition of FCS instead of BSA to mKRB solution and the presence of cumulus cells around oocytes prior to sperm insemintion may be responsible for the increase of in vitro fertilization and early cleavage rates.

• 한국치위생학회지
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• 제18권5호
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• pp.693-705
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• 2018

Objectives: This study aimed to identify the importance of the directivity of reflecting on a realistic task when aiming to reorganize a relevant law for dental hygienists through examining dental hygiene students' perceived need for a relevant law on dental hygiene related work. Methods: A survey was conducted targeting dental hygiene students from March 28 to April 30, 2018. The following findings were obtained. The results were summarized as follows. The collected data were analyzed using the SPSS WIN 21.0 statistical program. Results: With reference to the influence of the need for a work-related legislation on dental hygienists' awareness of their legal rights, findings revealed that the latter was higher when there was higher involvement in precision impression procedures, higher involvement in occlusal adjustment in the middle stage, and higher perceived need for legislation on a comprehensive dental hygiene course (all p<0.05). Conclusions: Based on these findings, it is considered necessary to pursue a national solution for modifying the relevant legal system to provide institutional support for dental hygienists' work. Additionally, the worry in the whole dentistry in order to establish dental hygienists' task.

• 한국토양비료학회지
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• 제33권1호
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• pp.32-39
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• 2000

하수 오니에 의한 Cd 의 흡착반응을 조사하기 위하여, Cd의 처리농도 (5, 10, 15, 20, 25 및 $50{\mu}g\;Cd\;ml^{-1}$를 달리하여 흡착실험을 수행하였으며, 반응시간 (흡착 반응 후 0.5, 1.0, 1.5, 2.5, 4.5, 6.6, 8.5, 12.5, 24.5 및 48.5 h) 별로 Cd 의 농도를 구하여 흡착반응의 속도상수를 계산하였다. 모든 처리 농도에서 처음 반응시간 30분 이내에 처리 한 Cd의 약 95% 가 흡착되었다. 초기의 빠른 1단계 Cd 흡착반응 후에는 1차 가역 반응식으로 기술할 수 있는 1단계 반응보다는 느린 2단계의 Cd 흡착 반응이 일어났다. 1차 가역 반응식으로 기술할 수 있는 2단계의 Cd 흡착 반응의 속도상수는 $-0.137{\sim}-0.521h^{-1}$의 범위로서 Cd처리 농도가 증가할수록 속도상수는 감소하였다. 흡착 반응에서 평형에 도달하는 시간 (약 6-24 h) 이나, 평형에서의 Cd 의 흡착량 (약 $276-2720{\mu}g\;g^{-1}$) 또는 흡착되지 않고 용액에 남아있는 Cd의 농도 (약 $60-400{\mu}g\;L^{-1}$) 도 Cd 의 처리 농도에 의하여 결정되었다. 즉 Cd 의 처리 농도가 증가할수록 평형에 도달하는 시간, 흡착량 및 평형 농도는 증가하였다. 하수 오니에 의하여 흡착된 Cd 의 일부는 시간이 경과함에 따라 하수 오니로 부터 방출되었으나 그 양은 전체 Cd 흡착량에 비하면 매우 적었다.

• 한국치위생학회지
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• 제10권4호
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• pp.663-670
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• 2010

Objectives : The purpose of this study is to measure employment stress of health college students and to consider a proper means for the solution. Methods : The population of the research is some randomly chosen health college students located in Seoul City during the period from May 10 to June 11 2010, and the sample of 295 students were recruited as the analysis object group. The data on general characteristics and employment stress were collected by a questionnaire survey. The collected data were analyzed with the SPSS WIN 12.0 program. The following shows the results of this study. Results : 1. Mean scores of employment stress in female students were significantly higher than those in male(p<0.01). 2. Employment stress level was significantly higher in low group of home economy, competence for a schoolwork, personal relations, satisfaction in campus life. 3. In regression analysis, home economy, competence for a schoolwork, satisfaction in campus life were proved as significant factors that is related to the employment stress(p<0.01). In other words, It is significant statistically that the lower home economy, competence for a schoolwork, satisfaction in campus life, the higher employment stress level (p<0.05). Conclusions : I suggest with the result of the study that for coping effectively employment stress of health college students, we will need to open an exclusive employment counsel window for better administration welfare service in campus. Because of students are independent responsibility of employment, active effort must take precedence in order for the solution of problem by themselves. Also, we will need to create better academic environment and show more concern, consideration, love in family.

• Membrane and Water Treatment
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• 제7권4호
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• pp.277-296
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• 2016

The aim of this research was to investigate the ability of nanofiltration (NF) and ultrafiltration (UF) membranes as a filtration unit for groundwater treatment for drinking water resources. Commercial membranes denoted as TS40, TFC-SR3 and GHSP were used to study the performance based on rejections and fluxes. The investigation has been conducted using natural groundwater obtained from a deep tube well with initial concentration of iron (Fe) and manganese (Mn) at 7.15 mg/L and 0.87 mg/L, respectively. Experimental results showed that NF membranes exhibited higher fluxes than UF membrane with pure water permeability at 4.68, 3.99 and $3.15L.m^{-2}.h^{-1}.bar^{-1}$, respectively. For metal rejection, these membranes have performed higher removal on Fe with TS40, TFC-SR3 and GHSP membranes having more than 82%, 92% and 86% respectively. Whereas, removal on Mn only achieved up to 60%, 80% and 30%, for TS40, TFC-SR3 and GHSP membranes respectively. In order to achieve drinking water standard, the membranes were efficient in removing Fe ion at 1 and 2 bar in contrast with Mn ion at 4 and 5 bar. Higher rejection of Fe and Mn were achieved when pH of feed solution was increased to more than 7 as TFC-SR3 membrane was negatively charged in basic solution. This effect could be attributed to the electrostatic effect interaction between membrane material and rejected ions. In conclusion, this study proved that NF membrane especially the TFC-SR3 membrane successfully treated local groundwater sources for public drinking water supply in line with the WHO standard.

• Journal of Nutrition and Health
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• 제40권6호
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• pp.531-541
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• 2007

This study was conducted to determine factors affecting detection threshold and the optimally-preferred concentration for sweet taste, since investigation into factors decreasing sensitivity or increasing preference for sweet taste is important to prevent overconsumption of simple sugar. Subjects were 70 first-grade middle school students in the Gyeonggi-Do. The detection threshold concentration of sucrose solution and the optimally-preferred sucrose concentration of omija jelly were determined by sensory evaluation. A self-administered questionnaire was used to obtain the information regarding health-related lifestyle practices, dietary habits, preference for and eating frequency of Westernized foods and frequencies of eating foods other than home-made. The detection threshold concentration of sucrose solution and the optimally-preferred sucrose concentration of omija jelly of the subjects were 0.204% and 14.44%, respectively. Subjects who exercise less (< 30 minutes/week except PE class), skipping meals (${\geq}$ 3/week), type of breakfast rather than traditional Korean meal and frequent eating out and buying foods from school tuck-shop tended to have higher sweet taste threshold. There was significant positive correlation between the sucrose threshold concentration and fried chicken preference or eating frequency of hamburger. Those who exercise less (< 30 minutes/week except PE class) did have significantly higher optimally-preferred sweetness of omija jelly, which tended to be higher in the subjects who had more (${\geq}$ 4 out of 10) behavioral or psychological stress symptoms and who had early getting-up time (before 7 am). There was significant positive correlations between the optimally-preferred sweetness of omija jelly and pizza preference, instant noodle eating frequency or sum of eating frequencies of five fast foods. From the results of this study, it was suggested that middle school students should make efforts to stop skipping meals, exercise more, eat Korean traditional breakfast and reduce the frequencies of eating out and using instant/fast foods in order to prevent overconsumption simple sugar.

• Restorative Dentistry and Endodontics
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• 제16권2호
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• pp.126-142
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• 1991

The purpose of this study was to evaluate the effect of various dentin surface treatments on shear bond strength, microhardness and fracture mode before and after thermocycling. Recently extracted 75 human molars were used. The teeth were sagittal sectioned faciolingually to obtain 150 specimens. They were randomly divided into six groups. Mesial and distal dentinal surfaces of specimens were exposed by grinding and treated respectively with GC-DENTIN CONDITIONER. 10-3 solution of 4-Meta, Cleansar and Primer of GLUMA, Scotchprep of Scotchbond 2, DENTIN CONDITIONER and PRIMER A, B of ALL BOND according to the manufacturers directions. Specimens of one group were not treated. Adhesive agent of Scotchbond 2, were applied and cured on the treated dentin surfaces. After P-50 were cured on them, specimens were stored in 31c water for 24 hours before shear bond strength measurement Shear bond strength was measured in 10 specimens of each group. 10 specimens of each group were thermocycled in $20^{\circ}C$, $60^{\circ}C$,$20^{\circ}C$, $4^{\circ}C$, $20^{\circ}C$ water in order, for 30 seconds respectively, 100 times a day for 7 days. After thermocycling shear bond strength was measured. Microhardness was checked on treated dentin surface and fractured dentin surface in 10 specimens respectievly. Francture modes were observed with SEM The following results were obtained. 1. Before thermocycling. shear bond strengths in the specimens treated with DENTIN CONDITIONER and PRIMER A, B of ALL BOND were significantly higher than those in other specimens(P<0.01). 2. After thermocycling. shear bond strengths in the specimens treated with Cleanser and Primer of GLUMA, Scotchprep of Scotchbond 2 and DENTIN CONDITIONER and PRIMER A, B of AIL BOND were significantly higher than those in specimens not: treated, treated with GC-DENTIN CONDITIONER and 10-3 solution of 4-Meta(P<0.01). Shear bond strengths in the specimens treated with GC-DENTIN CONDITIONER and PRIMER A, B of ALL BOND were significantly higher than those in other specimens except those treated with Scotchprep of Srotchbond 2(P<0.01). 3. Shear bond strengths after thermocycling were reduced in the specimens not treated, treated with GC-DENTIN CONDITIONER and 10-3 solution of 4-Meta and were increased in the specimens treated with Cleanser and Primer of GLUMA, Scotchprep of Scotchbond 2, without significance, compared with those before thermocycling. In the specimens treated with DENTIN CONDITIONER and PRIMER A, B of ALL BOND, shear bond strengths after thermocycling were significantly increased, compared with those before thermocycling(P<0.01). 4. Microhardnesses in the fractured surfaces after shear bond strength measurement were significantly increased in the specimens treated with 10-3 solution of 4-Meta and significantly decreased in the specimens treated with DENTIN CONDITIONER and PRIMER A, B of ALL BOND, compared with those in the treated dentin surfaces(P<0.01). 5. In the specimens treated with Cleanser and Primer of GLUMA, Scotchprep of Scotchbond 2 and DENTIN CONDITIONER and PRIMER A, B of ALL BOND, cohesive fracture modes were observed more than adhesive fracture modes.

• 한국식품영양과학회지
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• 제20권6호
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• pp.559-564
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• 1991

동치미의 저장성 향상효과를 보기 위하여 동치미 제조시와 발효시 열처리 및 염 첨가 등을 같이 행하여 >$25^{\circ}C$에서 발효시키면서 이들이 동치미의 pH, 산도, 텍스쳐, 환원당 및 관능적 품질 변화에 미치는 영향을 측정하였다. 그 결과 열처리와 무기산염 및 인산염을 같이 처리한 방법 B 및 C 처리구가 대조구에 비해 약 2~2.5배의 저장 연장 효과를 보였으며 총산도에서는 열처리 및 KCI, $CaCl_2 첨가를 같이한 방법 A구가 가장 낮은 함량을 나타내었다. 텍스쳐에서는 대체로 대조구에 비해 처리구의 견고성이 높았으며 환원당은 열수담금을 했던 방법 A, B, C는 담금초기부터 환원당의 농도가 높았으나 발효가 진행되면서 감소하여 대조구와 반대현상을 보여주었다. 한편 동치미의 관능적 평가에서는 처리구의 품질이 대조구보다 더 신선하여 같은 발효일에서 생무우내와 생무우맛은 많은 반면 신내와 신 맛은 적은 것으로 나타났다.

• 대한기계학회논문집
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• 제13권4호
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• pp.572-582
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• 1989

본 논문에서는 윗면에 균일한 압력을 받는 외팔보의 굽힘 변형과 고정 자유 지지된 무한길이 스트립의 폭 방향 굽힘변형을 위에 언급된 이론을 적용하여 살펴보고자 한다. 먼저 기본 지배방정식들을 요약하여 변형률의 1차항까지 나타내며 각 경우에 대해 변형을 중심선에 상대적인 단면의 변위와 단면의 회전 그리고 병진을 나타내며 각 경우에 대해 변형을 중심선에 상대적인 단면의 변위와 단면의 회전 그리고 병진을 나타내는 도심의 변위로 분해하고 도심에 상대적인 변위는 Michell에 의한 평판의 해와 St. Venant에 의한 봉의 해를 이용한다. 가정된 변위장으로부터 응력을 구한 다음 적절한 조건 하에서 국부평형방정식을 구하여 전체평형방정식을 유도한다. 또한 이로부터 각 단면의 회전과 중심선의 변위가 구해질 수 있음을 보인다.

• 자원리싸이클링
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• 제28권1호
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• pp.40-46
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• 2019

염산용액에서 유기인산 추출제(D2EHPA, PC88A, Cyanex 272) 단독, Alamine 336과의 혼합용매, Aliquat 336으로 제조한 이온성액체에 의한 터븀(III)의 용매추출을 조사하였다. 유기인산의 혼합용매와 이온성액체를 사용하면 단독 유기인산에 비해 수용액상의 평형 pH는 상승하였다. 세 종류의 유기인산 추출제중에서 Cyanex 272와 Aliquat 336과의 이온성액체에서만 터븀(III) 추출에 대해 상승효과가 있었다. 혼합용매에 의한 터븀(III)의 추출률은 단독조건보다 낮았으며 D2EHPA + Alamine 336 > PC88A + Alamine 336 > Cyanex 272 + Alamine 336의 순서로 추출률이 높았다. 이온성액체로 추출시 Cyanex 272 + Aliqaut 336 > PC88A + Aliquat 336 > D2EHPA + Aliquat 336 순서로 터븀(III)의 추출률이 높았다.