• 한국농공학회지
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• 제20권1호
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• pp.4599-4613
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• 1978

This study was intended to investigate the effects of bituminous material content of soil-cement mixtures on their durability. For the purpose, unconfined compressive strength test, Freeze-thaw test, and wet-dry test were performed with three types of soil. Each type of soil was mixed with three levels of cement content and each soil-cement mixture was mixed with four levels of bituminous material content. For the unconfined compressive strength test, Freeze-thaw test and wet-dry test, 324, 108, and 108-specimens were prepared respectively. Unconfined compressive strength was measured at age of 7-days, 14-days and 28-days using 108-specimens in each age. The soil-cement loss rate due to freeze-thaw and wet-dry were calculated after 12 cycles of test using 108-specimens in each test. The results are summarized as follows : 1. Optimum moisture content was increased with increase of cement content, but maximum dry density was changed irregulary with increase of the cement content. 2. The unconfined compressive strength was increased with increase of cement content, bituminous material content and curing age. Cement is more effective factor than bituminous material on unconfined compressive strength of soil-cement Mixture. 3. It is estimated as the most economical cement content that the recommended cement content of A.S.T.M. because increasing rate of unconfined compressive strength at age of 28-days was low when cement content is above the recommanded cement content of A.S.T.M. among all types of soil. 4. Although a portion of cement content is substituted for bituminous material, the necessary unconfined compressive strength can be obtained. 5. The soil-cement loss was more influenced by wet-dry than Freeze-thaw 6. The bituminous material is more effective on the decrease of soil-cement loss than increase of unconfined compressive strength 7. The void ratio of soil-cement mixture was changet irregularly with increase of cement content, but that was decreased in proportion to the increase of bituminous material content. 8. The regression equation between the unconfined compressive strength and soil-cement loss rate were obtained as table 7.

• 간호행정학회지
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• 제7권3호
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• pp.473-485
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• 2001

This study is intended to develop a reliable and appropriate instrument of the clinical nursing education. This research consisted of 4 steps. First step is construction of the content validity by 1 Korean literature professor and 1 teaching professor in Ga Chon Gil College, the pilot study for the content validity by 14 professors and survey with four points Likert Scale, which includes from the point 'strongly valid' to the point of 'strongly non-valid', by 113 head nurses who guide and evaluate the students in clinical practice. The third step is the test of validity and reliability of the preliminary evaluation tool. The fourth step is the test of validity and reliability of the developmental evaluation tool. The data were collected from Sep. 10th, 2001 to Sep. 28th, 2001. This study was analyzed by SPSS PC+ for descriptive statistics, factor analysis and Cronbach's Co-efficient Alpha of the collected data. The results of these analysis are like as follows. 1. Evaluation tool of Clinical practice consists of 16 items including four categories : factor 1 was labeled 'desirable attitude'(5 items), factor 2 was labeled 'correctly judgement and nursing problem solving'(4 items), factor 3 was labeled 'adaptive ability of nursing knowledge and skill'(4 items), factor 4 was labeled 'desirable human relationship'(3 items) and these contributed 71.992% of the variance in the total score. 2. Cronbach's Co-efficient Alpha for internal consistency was .9128 for the total 16 items. For further research, it need to develop a variable and reliable instrument of the student self-evaluation and instrument that based on community.

• 한국세라믹학회지
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• 제42권10호
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• pp.698-702
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• 2005

Dielectric and Piezoelectric properties of complex perovskite 0.92Pb($Zr_{1/2}Ti_{1/2})O_{3}-(0.08-x)Pb(Cu_{1/3}Nb_{2/3})O_{3}-xPb(Mn_{1/3}Nb_{2/3})O_{3}(0{\leq}x{\leq}0.080$) (PZT-PCN-PMN) system were investigated as a function of PMN content. With the increase of PMN content of the sintered specimens, tetragonal phase was coexisted with rhombohedral phase, the dielectric constant was decreased, mechanical quality factor ($Q_{m}$) was inceased, and optimal sintering temperature was increased up to 1050$^{\circ}C$. For the composition of x = 0.064 sintered at 1050$^{\circ}C$ for 2 h, 1939 of maximum mechanical quality factor ($Q_{m}$), 57$\%$ of electromechanical coupling factor ($k_{p}$), and 1100$^{\circ}C$ of dielectric constant, 0.37$\% $ of dielectric loss (tan $\delta$) were obtained.

• 한국토양환경학회지
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• 제5권3호
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• pp.65-75
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• 2001

본 연구는 제주도의 전체 지하수공 중 수역별로 대표성이 있는 150공을 선정하여 고도에 따른 수질 특성을 파악하는데 목적을 두었다. 수질특성의 평가는 물리.화학적 특성과 통계분석을 이용하였다. Piper diagram에 의한 수질 유형은 표고 50m이하 지역은 $Na^{+}$＋ $K^{+}$-C $l^{-}$ 형태를 보이고 있다. 40~100 m에 위치한 지하수에서는 $Na^{+}$＋ $K^{+}$-HC $O_3$$^{-}$ ＋C $O_3$$^{2-}$ 형태와 일부 $Na^{+}$＋ $K^{+}$-C $l^{-}$ 형태의 군을 이루고 있다. 그리고 100 m이상의 지역에서는 $Na^{+}$＋ $K^{+}$-HC $O_3$$^{-}$ ＋C $O_3$$^{2-}$ 형태에 속하고 있다. 요인분석 결과, 50 m이하와 100 m이상 지역에서 공통적으로 TDS와 오염물질 2개 요인이 추출되었다. 50~100m지역에는 3개의 요인이 추출되었으며, 요인1에는 TDS함량으로 요인2는 오염의 영향과 광물용해로 볼 수가 있다. 그리고 요인 3에는 HC $O_3$$^{-}$ 함량으로 나타났다..

• 여성건강간호학회지
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• 제8권1호
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• pp.106-115
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• 2002

Little is known about sexual autonomy in the light of human sexual health or sexual behavior. The purpose of this study was to increase understanding of sexual autonomy by developing a scale to measure sexual autonomy in college students. The measure was based on the perspective of human beings as having autonomy. A methodological developmental design was used. The study was done in three steps and included concept development through content analysis of relevant literature individual interviews using open-ended questions with 19 college students, item analysis of data from self report questionnaires for item to total correlation, content validity index by professionals and college students, and factor analysis with principal component analysis. Three groups participated in testing the measurement scale; Group A in 1998, a nationwide convenience sample of college students (n=1,163), Group B, college students in 1999 (n=233), and Group C, college students in 2000 who responded to the measurement scale before and after a sex education program (n=216). A series of exploratory and confirmatory factor analyses were conducted to test validity. For analysis of the questionnaires, statistical methods including reliability (test-retest), item to total analysis, content validity, factor analysis for construct validity and t-test for mean difference according to gender, sexual coitus, previous sex education, and pre-post experiment sex education were used with SPSS 10.0. Results: 1. Two stable factors were extracted and these contributed 48.05% of the variance in the total score. All 13 items loaded above .40 on each factor. 2. Factor I with 10 items was named 'control' and factor II with 3 items and was named 'coping'. 3. Differences in sexual autonomy scores for college students according to their experience showed that there were significantly higher scores for sexual autonomy in the post sex education group(t=-10.841, p=.000), but there were no differences according to whether or not they had previous sex education. Female college students had higher sexual autonomy scores than male college students in A or B group (t=-5.933, p=.000/ t=-1.992, p=.048). 4. Cronbach's $\alpha$ was .8603 for the total 13 items with 1,632 college students, .8739 with 232 students, .8333$\sim$.7647 with pre-post sex education with 216 students. This measurement was found to have a high validity and reliability for measuring sexual autonomy in college students. Therefore, the author recommends that it be used to measure the effects of sex education. It is suggested that further study is needed to analyze the relationship between sexual autonomy and sexual behavior.

• 자원환경지질
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• 제22권2호
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• pp.141-150
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• 1989

In order to make economic and geological evaluation of coal in Korea, proximate and ultimate analyses were carried out as well as coal petrological studies such as maceral analyses, vitrinite reflectance and sporinite fluorescence measurement. The coeffcient of correlation between each factor of both conventional utilization and coal petrological parameters were studied as in Table 5 and 6. Their conclusions were as follow: (1) for anthracite, the good parameters of coal rank are mean vitrinite reflectance, carbon content, hydrogen content and H/C atomic ratio: (2) for brown coal and sub-bituminous coal, the good parameters of coal rank are carbon content, calorific value, moisture content, hydrogen content, oxygen content and O/C atomic ratio as well as vitrinite reflectance and sporinite fluorescence. An attempt is made to infer the coalforming environment by utilization of coal petrological analyses and to make comparison of coal analyses with proximate and ultimate analyses throughout the island arc region including Japan, Philippine and Indonesia and continental region including USA, Canada and Australia. As a result, meceral composition of Paleozoic and Mesozoic anthracite are similar to that of the Paleozoic continental coals, which were formed under dry conditions or low water table, but the coalification degree suddenly increased during Daebo orogeny (middle Jurassic to lower Cretaceous). The Tertiary coal resembles those of Tertiary island arc region coal characterized by higher calorific value, volatile matter content and H/C atomic ratio and by the formation of coal under wet conditions or higher water table.

• 한국지역사회생활과학회지
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• 제25권2호
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• pp.261-269
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• 2014

This study evaluates the nutritional retention factors influencing beef based on different cuts and boiling. Two cuts (brisket and shin foreshank) were prepared from beef and used in this experiment. Boiling methods were applied to each cut. The fat content of the boiled shin foreshank cut (236.43%) exceeded that of the brisket cut (142.38%). The moisture content of the boiled brisket cut (47.68%) was lower than that of the shin foreshank cut (49.54%). The sodium content of the boiled shin foreshank cut (47.89%) exceeded that of the brisket cut (37.30%). The potassium content of the boiled brisket cut (41.90%) exceeded that of the shin foreshank cut (39.63%). The calcium content of the boiled brisket cut (48.43%) was lower than that off the shin foreshank cut (71.34%). The phosphorus content of the boiled brisket cut (58.09%) exceeded that of the shin foreshank cut (57.24%). The iron content of the boiled brisket cut (72.72%) was lower than that of the shin foreshank cut (87.29%). Nutritional retention factors represent output data on cooking methods with a yield (%) for each item.

• Food Science and Biotechnology
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• 제16권3호
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• pp.381-385
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• 2007

The objective of this experiment was to study the influence of feed moisture content on the degree of enzymatic hydrolysis of com starch in a twin screw extruder and the saccharification yield of the dried extrudate. The feed moisture content was set at 25, 30, and 35% and ${\alpha}$-amylase solution was directly injected into the feed section at a barrel temperature of $95^{\circ}C$ and screw speed of 250 rpm. Amyloglucosidase was used for the saccharification of the dried extrudate at a concentration of 0.055%(w/w). Expansion ratio and swelling factor of extrudates decreased with increasing the feed moisture content. Addition of ${\alpha}$-amylase during extrusion process raised reducing sugar content of extrudates which also increased with the feed moisture content. The saccharification yield of dried extrudate was higher for the extrudate with lower feed moisture content.

• 한국식품저장유통학회지
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• 제31권3호
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• pp.499-505
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• 2024

Patulin has been reported as a risk factor in various foods, especially apple juice. This study monitored residual patulin and polyphenolic content in apple juice during post-irradiation storage conditions. Response surface methodology (RSM) was applied to monitor the changes in dependent variables (Yn, patulin, and polyphenolics) as affected by independent variables, such as storage temperature (Xi, -20℃ to 20℃), irradiation dose (Xii, 0-2 kGy), and storage period (Xiii, 0-20 days), which were based on a central composite design. The predicted peak point resulted in the lowest residual patulin content of 58.42 ppb with the corresponding independent parameter conditions, such as 18.19℃ of storage temperature, 1.24 kGy of irradiation dose, and 13.42 days of storage period. The residual patulin content of 58.42 ppb is the minimum desirable level, representing a 91% reduction compared to the non-irradiated control (675.00 ppb). A maximum polyphenolics content (11.98 mg/g) was obtained under the predicted maximum conditions of 14.40℃, 0.78 kGy, and 3.4 days. The most influential parameter in reducing residual patulin content while maintaining polyphenolic content in apple juice was irradiation dose (p<0.01), which showed potential to be applied in controlling the patulin levels in apple juice.

• 폴리머
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• 제31권6호
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• pp.474-478
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• 2007

다이사이클로펜타다이에닐 비스페놀 시아네이트 에스터 올리고머와 열가소성 수지인 폴리페닐렌에테르(PFE)를 복합체화함으로써 유전손실이 적은 고분자 기판소재를 제작하였다. 올리고머와 촉매의 경화반응을 분석하여 최적 촉매첨가량을 Zn 0.02 phr로 선정하고 이를 복합체 제작에 적용하였다. 올리고머와 PPE의 함량비를 변화시키며 제작된 복합체의 동박 박리 강도, gel content 등을 측정하였으며, GHz 대역에서의 유전율과 유전손실을 평가하였다. PPE의 함량은 박리 강도 및 유전특성에 큰 영향을 주었으나, 촉매의 함량에 따라서는 유전특성에 큰 차이가 없었다. 실험결과 박리 강도가 1 kN/m 이상이고, 1 GHz에서 유전손실이 0.004로 낮은 고분자 복합체 라미네이트를 얻을 수 있었다.