• Korean Journal of Environmental Biology
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• v.38 no.1
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• pp.93-100
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• 2020

Hybrid grouper (Epinephelus fuscoguttatus ♀×E. lanceolatus ♂) (mean weight 27.3±3.8 g, mean length 11.6±0.7 cm) were exposed to waterborne nitrite at 0, 100, 200, 400, 800, and 1600mg L^-1 for 96 hours. The hematocrit and hemoglobin values were significantly decreased by exposure to 100 mg L^-1 and 400 mg L^-1, respectively. In plasma components, no significant change was observed in magnesium. Glucose was significantly increased by 200 and 400 mg L^-1 nitrite but reduced by 800 mg L^-1. Cholesterol was significantly decreased by 400 mg L^-1 nitrite, but there was no significant change in total protein. GPT(glutamic pyruvate transaminase) was significantly increased by exposure to 200 and 400mg L^-1. ALP(Alkaline phosphatase) was significantly increased by 800 mg L^-1. The results of this study indicate that acute exposure to nitrite changes physiological parameters, such as hematological properties and plasma components.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.29 no.8
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• pp.461-465
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• 2016

n-type silicon shows the better tolerance towards metal impurities with a higher minority carrier lifetime compared to p-type silicon substrate. Due to better lifetime stability as compared to p-type during illumination made the photovoltaic community to switch toward n-type wafers for high efficiency silicon solar cells. We fabricated the front electrode of the n-type solar cell with AgAl paste. The electrodes characteristics of the AgAl paste depend on the contact junction depth that is closely related to the firing temperature. Metal contact depth with p+ emitter, with optimized depth is important as it influence the resistance. In this study, we optimize the firing condition for the effective formation of the metal depth by varying the firing condition. The firing was carried out at temperatures below $670^{\circ}C$ with low contact depth and high contact resistance. It was noted that the contact resistance was reduced with the increase of firing temperature. The contact resistance of $5.99m{\Omega}cm^2$ was shown for the optimum firing temperature of $865^{\circ}C$. Over $900^{\circ}C$, contact junction is bonded to the Si through the emitter, resulting the contact resistance to shunt. we obtained photovoltaic parameter such as fill factor of 76.68%, short-circuit current of $40.2mA/cm^2$, open-circuit voltage of 620 mV and convert efficiency of 19.11%.

• Progress in Medical Physics
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• v.13 no.1
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• pp.21-26
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• 2002

A practical calculation algorithm which calculates the relative output factor(ROF) for irregular shaped electron field has been developed and evaluated the accuracy of the algorithm. The algorithm adapted two-source model, which assumes that the electron dose can be express as sum of the primary source component and the scattered component from the shielding block. Original two-source model has been modified in order to make the algorithm simpler and to reduce the number of parameters needed in the calculation, while the calculation error remains within clinical tolerance range. The primary source is assumed to have Gaussian distribution, while the scattered component follows the inverse square law. Depth and angular dependency of the primary and the scattered are ignored ROF can be calculated with three parameters such as, the effective source distance, the variance of primary source, and the scattering power of the block. The coefficients are obtained from the square shaped-block measurements and the algorithm is confirmed from the rectangular or irregular shaped-fields used in the clinic. The results showed less than 1.0 ％ difference between the calculation and measurements for most cases. None of cases which have bigger than 2.1 ％ have been found. By improving the algorithm for the aperture region which shows the largest error, the algorithm could be practically used in the clinic, since one can acquire the 1011 parameter's with minimum measurements(5∼6 measurements per cones) and generates accurate results within the clinically acceptable range.

• Korean Journal of Environmental Biology
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• v.31 no.4
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• pp.440-447
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• 2013

The ecological health, based on the Index of Biological Integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) was evaluated in 10 stream sites of Southern Han River. Eleven parameters of 12 parameters (Karr 1981) were modified for the application of regional Korean circumstance. The ecological health, based on IBI grade, was in "good condition" and the IBI score ranged from 33 to 47. Nine parameters of the original 12-parameter metrics in QHEI model (Plafkin et al. 1989) were applied in the habitat assessment. The mean QHEI model values were judged as "partially supporting" and ranged from 75 (non-supporting) to 109 (supporting). Comparative analyses revealed that values of IBI and QHEI models were greater in Gj stream than Ig- and Dn streams. The analysis of fish compositions showed that the proportions of insectivore, omnivore, and carnivore were 61.9%, 19%, and 9.5%, respectively. According to tolerance guild analysis, sensitive species and tolerant species were 76.1% and 4.7%, respectively, indicating a healthy trophic state in terms of food chain. The analysis by habitat guild type indicated that riffle benthic species dominated (57.1%) when compared to water column species (28.5%). The introduced species and individuals with diseases or external abnormality were not observed. Overall, the model values of IBI and QHEI suggested that the ecological health was maintained well in this upstream region.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.973-979
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• 2005

To investigate the effect of Pinus densiflora on biochemical parameters in type I diabetic rats, we evaluated the changes of body weight, fasting blood glucose level, oral glucose tolerance test (OGTT) and biochemical parameters after the intraperitoneal injection of distilled solution of Pinus densiflora in streptozotocin (STZ)­induced rats. Thirty-seven male Sprague Dawley rats $(180\pm10g)$ were divided into four groups; diabetic mellitus (DM) group received STZ (50 mg/kg BW, i.v.); low level of pine extract (LP) group received Pinus densiflora (5 mg/kg BW, i.p.), high level of pine extract (HP) group received Pinus densiflora (10 mg/kg BW, i.p.) after the single injection of STZ (50 mg/kg BW, i.v.), respectively. Normal control (NC) group received saline. The change of fasting blood glucose level and OGTT were measured using glucocard II, and the change of biochemical parameter were measured by Automatic Chemistry Analyzer (Hitach-747, Japan). Mean body weight change of DM group was retarded greatly by STZ-exposure. While, body weights of LP and HP groups were progressively increased with some fluctuation, although the increase rates were slower than that of NC group. Fasting blood glucose levels of LP and HP groups were reduced by Pinus densiflora injection, although the fasting blood glucose levels were higher than that of NC group. The results of OGTT was significantly improved in both of LP and HP group compared to DM group. Increases of blood glucose, alanine aminotransferase (ALT), alkaline phosphatase (ALP) and blood urea nitrogen (BUN) levels by STZ-exposure were attenuated by the Pinus densiflora treatment (p<0.05). From the results, it was suggested that Pinus densiflora has a tendency to decrease STZ-induced toxicity in terms of monitoring fasting blood glucose, OGTT and some biochemical parameters of rat.

• Korean small business review
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• v.31 no.2
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• pp.103-120
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• 2009

As business incubation centers (BICs) have been operating for more than 10 years in Korea, many early stage startups tend to use the services provided by the incubating centers. BICs in Korea have accumulated the knowledge and experience in the past ten years and their services have been considerably improved. The business incubating service has three facets : (1) business infrastructure service, (2) direct service, and (3) indirect service. The mission of BICs is to provide the early stage entrepreneurs with the incubating service in a limited period time to help them grow strong enough to survive the fierce competition after graduating from the incubation. However, the incubating services sometimes fail to foster the independence of new startup companies, and raise the dependence of many companies on BICs. Thus, the dependence on BICs is a very important factor to understand the survival of the incubated startup companies after graduation from BICs. The purpose of this study is to identify the main factors that influence the firm's dependence on BICs and to characterize the relationships among the identified factors. The business incubating service is a core construct of this study. It includes various activities and resources, such as offering the physical facilities, legal service, and connecting them with outside organizations. These services are extensive and take various forms. They are provided by BICs directly or indirectly. Past studies have identified various incubating services and classify them in different ways. Based on the past studies, we classify the business incubating service into three categories as mentioned above : (1) business infrastructure support, (2) direct support, and (3) networking support. The business infrastructure support is to provide the essential resources to start the business, such as physical facilities. The direct support is to offer the business resources available in the BICs, such as human, technical, and administrational resources. Finally, the indirect service was to support the resource in the outside of business incubation center. Dependence is generally defined as the degree to which a client firm needs the resources provided by the service provider in order to achieve its goals. Dependence is generated when a firm recognizes the benefits of interacting with its counterpart. Hence, the more positive outcomes a firm derives from its relationship with the partner, the more dependent on the partner the firm must inevitably become. In business incubating, as a resident firm is incubated in longer period, we can predict that her dependence on BICs would be stronger. In order to foster the independence of the incubated firms, BICs have to be able to manipulate the provision of their services to control the firms' dependence on BICs. Based on the above discussion, the research model for relationships between dependence and its affecting factors was developed. We surveyed the companies residing in BICs to test our research model. The instrument of our study was modified, in part, on the basis of previous relevant studies. For the purposes of testing reliability and validity, preliminary testing was conducted with firms that were residing in BICs and incubated by the BICs in the region of Gwangju and Jeonnam. The questionnaire was modified in accordance with the pre-test feedback. We mailed to all of the firms that had been incubated by the BICs with the help of business incubating managers of each BIC. The survey was conducted over a three week period. Gifts (of approximately ₩10,000 value) were offered to all actively participating respondents. The incubating period was reported by the business incubating managers, and it was transformed using natural logarithms. A total of 180 firms participated in the survey. However, we excluded 4 cases due to a lack of consistency using reversed items in the answers of the companies, and 176 cases were used for the analysis. We acknowledge that 176 samples may not be sufficient to conduct regression analyses with 5 research variables in our study. Each variable was measured through multiple items. We conducted an exploratory factor analysis to assess their unidimensionality. In an effort to test the construct validity of the instruments, a principal component factor analysis was conducted with Varimax rotation. The items correspond well to each singular factor, demonstrating a high degree of convergent validity. As the factor loadings for a variable (or factor) are higher than the factor loadings for the other variables, the instrument's discriminant validity is shown to be clear. Each factor was extracted as expected, which explained 70.97, 66.321, and 52.97 percent, respectively, of the total variance each with eigen values greater than 1.000. The internal consistency reliability of the variables was evaluated by computing Cronbach's alphas. The Cronbach's alpha values of the variables, which ranged from 0.717 to 0.950, were all securely over 0.700, which is satisfactory. The reliability and validity of the research variables are all, therefore, considered acceptable. The effects of dependence were assessed using a regression analysis. The Pearson correlations were calculated for the variables, measured by interval or ratio scales. Potential multicollinearity among the antecedents was evaluated prior to the multiple regression analysis, as some of the variables were significantly correlated with others (e.g., direct service and indirect service). Although several variables show the evidence of significant correlations, their tolerance values range between 0.334 and 0.613, thereby demonstrating that multicollinearity is not a likely threat to the parameter estimates. Checking some basic assumptions for the regression analyses, we decided to conduct multiple regression analyses and moderated regression analyses to test the given hypotheses. The results of the regression analyses indicate that the regression model is significant at p < 0.001 (F = 44.260), and that the predictors of the research model explain 42.6 percent of the total variance. Hypotheses 1, 2, and 3 address the relationships between the dependence of the incubated firms and the business incubating services. Business infrastructure service, direct service, and indirect service are all significantly related with dependence (β = 0.300, p < 0.001; β = 0.230, p < 0.001; β = 0.226, p < 0.001), thus supporting Hypotheses 1, 2, and 3. When the incubating period is the moderator and dependence is the dependent variable, the addition of the interaction terms with the antecedents to the regression equation yielded a significant increase in R2 (F change = 2.789, p < 0.05). In particular, direct service and indirect service exert different effects on dependence. Hence, the results support Hypotheses 5 and 6. This study provides several strategies and specific calls to action for BICs, based on our empirical findings. Business infrastructure service has more effect on the firm's dependence than the other two services. The introduction of an additional high charge rate for a graduated but allowed to stay in the BIC is a basic and legitimate condition for the BIC to control the firm's dependence. We detected the differential effects of direct and indirect services on the firm's dependence. The firms with long incubating period are more sensitive to indirect service positively, and more sensitive to direct service negatively, when assessing their levels of dependence. This implies that BICs must develop a strategy on the basis of a firm's incubating period. Last but not least, it would be valuable to discover other important variables that influence the firm's dependence in the future studies. Moreover, future studies to explain the independence of startup companies in BICs would also be valuable.