• Bulletin of the Korean Chemical Society
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• v.32 no.1
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• pp.263-272
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• 2011

Highly luminescent and monodisperse InP quantum dots (QDs) were prepared by a non-organometallic approach in a non-coordinating solvent. Fatty acids with well-defined chain lengths as the ligand, a non coordinating solvent, and a thorough degassing process are all important factors for the formation of high quality InP QDs. By varying the molar concentration of indium to ligand, QDs of different size were prepared and their absorption and emission behaviors studied. By spin-coating a colloidal solution of InP QD onto a silicon wafer, InP QD thin films were obtained. The thickness of the thin films cured at 60 and $200^{\circ}C$ were nearly identical (approximately 860 nm), whereas at $300^{\circ}C$, the thickness of the thin film was found to be 760 nm. Different contrast regions (A, B, C) were observed in the TEM images, which were found to be unreacted precursors, InP QDs, and indium-rich phases, respectively, through EDX analysis. The optical properties of the thin films were measured at three different curing temperatures (60, 200, $300^{\circ}C$), which showed a blue shift with an increase in temperature. It was proposed that this blue shift may be due to a decrease in the core diameter of the InP QD by oxidation, as confirmed by the XPS studies. Oxidation also passivates the QD surface by reducing the amount of P dangling bonds, thereby increasing luminescence intensity. The dielectric properties of the thin films were also investigated by capacitance-voltage (C-V) measurements in a metal-insulator-semiconductor (MIS) device. At 60 and $300^{\circ}C$, negative flat band shifts (${\Delta}V_{fb}$) were observed, which were explained by the presence of P dangling bonds on the InP QD surface. At $300^{\circ}C$, clockwise hysteresis was observed due to trapping and detrapping of positive charges on the thin film, which was explained by proposing the existence of deep energy levels due to the indium-rich phases.

• Food Science of Animal Resources
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• v.24 no.2
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• pp.156-163
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• 2004

This study was carried out to investigate the improvement of stretchability in Mozzarella cheese based on the influence of various factors such as starter type, fat content, salt content and stretching temperature. To do this study, stretchability, meltability, fat leakage and the change of soluble nitrogen compound were measured during storage of the Mozzarella cheese at 4$^{\circ}C$ for 10 weeks. When L bulgaricus starter was added, stretchability of the cheese was excellent and cheese manufactured with starter of L bulgaricus and L. bulgaricus : Str. thermophilus = 1:2 improved meltability because of high soluble nitrogen compound. When salt content of cheese was 0.5％, this resulted in extreme deterioration of quality in regard to stretchability, meltability and fat leakage at five weeks and when salt content of cheese was 0.5, 1.0 and 1.5％, soluble nitrogen compound was 4.49, 4.45 and 2.61 ％ at one week and 19.71, 19.44％ and 17.07％ at eight weeks, respectively. Stretchability was good at high stretching temperature, and cheese with stretching at 60'C showed poor meltability at the first stage, but this cheese had good meltability in process of time because increase in soluble nitrogen compound was high at low stretching temperature.

• Journal of Ecology and Environment
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• v.42 no.1
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• pp.1-11
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• 2018

Background: In the study, the effects of elevated $CO_2$ and temperature on the nitrogen content, carbon content, and C:N ratio of seven rare and endangered species (Quercus gilva, Hibiscus hambo, Paliurus ramosissimus, Cicuta virosa, Bupleurum latissimum, Viola raddeana, and Iris dichotoma) were examined under control (ambient $CO_2$ + ambient temperature) and treatment (elevated $CO_2$ + elevated temperature) for 3 years (May 2008 and June 2011). Results: Elevated $CO_2$ concentration and temperature result in a decline in leaf nitrogen content for three woody species in May 2009 and June 2011, while four herb species showed different responses to each other. The nitrogen content of B. latissimum and I. dichotoma decreased under treatment in either 2009 and 2011. The leaf nitrogen content of C. virosa and V. raddeana was not significantly affected by elevated $CO_2$ and temperature in 2009, but that of C. virosa increased and that V. raddeana decreased under the treatment in 2011. In 2009, it was found that there was no difference in carbon content in the leaves of the six species except for that of P. ramosissimus. On the other hand, while there was no difference in carbon content in the leaves of Q. gilva in the control and treatment in 2011, carbon content in the leaves of the remaining six species increased due to the rise of $CO_2$ concentration and temperature. The C:N ratio in the leaf of C. virosa grown in the treatment was lower in both 2009 and 2011 than that in the control. The C:N ratio in the leaf of V. raddeana decreased by 16.4% from the previous year, but increased by 28.9% in 2011. For the other five species, C:N ratios increased both in 2009 and 2011. In 2009 and 2011, chlorophyll contents in the leaves of Q. gilva and H. hamabo were higher in the treatment than those in the control. In the case of P. ramosissimus, the ratio was higher in the treatment than that in the control in 2009, but in 2011, the result was the opposite. Among four herb species, the chlorophyll contents in the leaves of C. virosa, V. raddeana, and I. dichotoma did not show any difference between gradients in 2009, but decreased due to the rise of $CO_2$ concentration and temperature in 2011. Leaf nitrogen and carbon contents, C:N ratio, and chlorophyll contents in the leaves of seven rare and endangered species of plant were found to be influenced by the rise and duration of $CO_2$ concentration and temperature, species, and interaction among those factors. Conclusions: The findings above seem to show that long-term rise of $CO_2$ concentration, and temperature causes changes in physiological responses of rare and endangered species of plant and the responses may be species-specific. In particular, woody species seem to be more sensitive to the rise of $CO_2$ concentration and temperature than herb species.

• Journal of Environmental Science International
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• v.22 no.7
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• pp.787-799
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• 2013

The aim of this study was to investigate the accumulation of metallic elements and the control effect of marine pollution caused by ocean dumping in the sediments at a waste disposal area in the Yellow Sea. In July 2009, concentrations of organic matter and metallic elements (Al, Fe, As, Cd, Cr, Co, Hg, Ni, Mn, Pb, and Zn) were measured in surface sediments at the site. The ignition loss (IL) in the surface sediments showed a mean value of 15.4%, about 1.5 times higher than the mean value of the sediments in the coastal areas of Korea. The chemical oxygen demand (COD) at some disposal sites exceeded 20 mg $O_2/g{\cdot}dry$, which signifies the initial concentration of marine sediment pollutants in Japan. The disposal sites contain higher concentrations of Cr, Cu and Zn than the sediments of bays and estuaries that might be contaminated. The magnitude of both metal enrichment factors (EF) and adverse biological effects suggest that pollution with Cr and Ni occurred due to the dumping of waste in the study area. In addition, the geoaccumulation index (Igeo) showed that the surface sediments were moderately contaminated. By the mid-2000s, when the amount of waste dumped at this site was the highest, the concentration of metallic elements was higher than ever recorded. On the other hand, in 2008-09, the need for environmental management was relatively low compare with the peak. As a result, the quality of marine sediment has been enhanced, considering the effect of waste reduction and natural dilution in the disposal area.

• The korean journal of orthodontics
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• v.36 no.6
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• pp.442-450
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• 2006

Objective: Many factors are considered when a patient chooses the type of dental institution they wish to receive treatment from. Numerous studies have been conducted regarding this issue. However, more research is needed in analyzing the patient's psychological aspects when he/she decides to choose the dental institution they wish to receive treatment from. Methods: A locus of control test was utilized to analyze the psychological aspects in orthodontic patients of a university dental hospital and a private dental clinic. The locus of control test is known to be useful in predicting a human being's behavior. Both intrinsic and extrinsic locus of control tests were carried out in 934 orthodontic patients attending Seoul National University Dental Hospital and 1466 orthodontic patients from a private dental clinic. Results: The orthodontic patients at the university dental hospital showed a stronger extrinsic locus of control compared with those from the private dental clinic. Conclusion: The orthodontic patients at the university dental hospital value the doctor as the authority figure and the treatment quality more than those at the private dental clinic.

• Journal of Gastric Cancer
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• v.7 no.1
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• pp.47-54
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• 2007

Purpose: To investigate the characteristics and chronological changes of gastric cancer in Korea, the Information Committee of the Korean Gastric Cancer Association performed nationwide survey for 2004. Materials and Methods: The data on patients who underwent gastric cancer surgery in 2004 were collected from 57 institutes and compared with those of 1995 and 1999 which were reported in 2002. Fourteen factors (sex, age, tumor location and size, gross type, approach to operation, radicality, operative method, reconstruction method, WHO and Lauren classification, UICC stage, and numbers of positive and retrieved lymph nodes) were analyzed. According to the annual number of gastric cancer operations, 57 institutes were divided into 4 groups (group 1, <100; 100 ${\leq}$ group 2 < 200 operations; 200 ${\leq}$ group 3 < 500 operations; group 4, ${\geq}500$). Results: Data on 11,293 patients were collected. The sex ratio (M : F) was 2.05 : 1 (7,586/3,705). The mean age was 58.0 years old. The age of highest incidence in both male and female has increased recently. The proportion of early gastric cancer has increased from 28.6% in 1995 and 32.8% in 1999 to 47.4% in 2004. The mean number of retrieved lymph nodes was 34.0 (32.8, 34.0, 36.1, and 32.9 for group 1, 2, 3, and 4 respectively). Conclusion: Early gastric cancer has increased in 2004 compared to 1995 and 1999. Gastric cancer surgery seems to be performed with acceptable quality in view of number of retrieved lymph nodes. These data presented in nationwide survey could be used as a fundamental resource for gastric cancer in Korea.

• Journal of Radiation Protection and Research
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• v.40 no.4
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• pp.202-210
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• 2015

The low dose radiation is done for a long period, thus researchers have to know the exact dose distribution for the irradiated mouse. This research has been conducted in order to find out methods in transmitting an exact dose to mouse in a mouse irradiation experiment carried out using $^{137}Cs$ irradiation equipment installed in the DIRAMS (Dongnam Institution of Radiological & Medical Sciences) research center. We developed a single mouse housing cage and shelf with adjustable geometric factors such as distance and angle from collimator. The measurement of irradiated dose showed a maximal 42% difference of absorbed dose from the desired dose in the conventional irradiation system, whereas only 6% difference of the absorbed dose was measured in the self-developed mouse apartment system. In addition, multi mice housing showed much difference of the absorbed dose in between head and body, compared to single mouse housing in the conventional irradiation system. This research may allow further research about biological effect assessment for the low dose irradiation using the self-developed mouse apartment to provide more exact doses which it tries to transmit, and to have more reliability for the biological analysis results.

• Culinary science and hospitality research
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• v.15 no.1
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• pp.254-270
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• 2009

As consumers are becoming more conscious about food safety and high quality standards, they are getting more interested in influencing the food policy-making process. Triggered by FTA (Free Trade Agreement) ratification between the Republic of Korea and the U.S. in 2008, a sharp conflict was created in importing U.S. beef between the government of Republic of Korea and its people. Food selection is known as a complex mental process of consumers, which incorporates social and cultural values, personal tastes, and other psychological factors. This study utilized the concept of antinomy which was signified by Immanuel Kant in his thesis. The concept of antinomy indicates a contradiction between conclusions which seem equally logical, reasonable or necessary. This study is designed to investigate the changes in the amount of beef consumption among Korean consumers after the Republic of Korea resumed U.S. beef imports and the impact of a consumer's trust in the U.S. on his/her antinomic acceptance. Also, it examined the effects of antinomic acceptance and whether a consumer is a potential restaurateur or a general consumer on the changes in the amount of beef consumption.

• Korean Journal of Social Welfare
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• v.38
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• pp.284-308
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• 1999

This study is about the nationwide research concerning the degree and trends of marital conflict and instability. The research samples are 1,217 married. As the result of the research, the most conflict able issues in Korean couples are on the husband-wife relations, such as habitual differences, sharing in houseworks, conflicts in the role expectation, and the communication problems. In this study, We devide the marital relationships into 4 types (A, B, C, and D) in the view of the satisfaction & instability of marriage. First, the marriage with unsatisfaction and instability (A) was portioned 8.3%, and the satisfactory & stable type (D) was portioned 68.4%. It seems the marital relationships in Korea are relatively stable. However, the portion of type B-unsatisfactory, but stable couples-is 17.1% and the type C-satisfactory, but unstable marriage 6.2%. The result implies that the indication of marital instability should consider not only the divorce rate, but also the quality of marital relationships. In other words, the intervention for the conflict couples yet not divorce is needed. The differences of conflict areas among the relational types is not so much, but the degrees on conflicts are very serious. Especially, in the areas of marital conflict, love issues and personal value system affect the division of relational types of marriage most. It means the interaction factors are the most important variables about maintaining the marital relations with stable and satisfaction.

• Journal of the Korean Society of Food Science and Nutrition
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• v.34 no.7
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• pp.1028-1034
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• 2005

The purposes of this study were to: (a) identify students' patronage behaviors on university foodservice, (b) evaluate customers' perception and detect complaints on food service quality, and (c) recommend new design of food service operation by identifying relative importance of university foodservice attributes. The questionnaire was developed and distributed to 400 undergraduates. Statistical data analysis was completed using SPSS/Win 12.0 for descriptive analysis and conjoint analysis. The results of this study were summarized as follows: Students were patronizing university foodservice 3.4 times per week because of 'a short distance', 'a low price' and 'speedy meals' and evaluated overall satisfaction and value as low level. Customers were dissatisfied with eight among twelve food service attributes including handling customer's complain ASAP, According to conjoint analysis, price $(37\%)$ was considered as the most important factor and atmosphere $(30\%),\;food\;(22\%)$ and distance $(11\%)$ were the next factors. Profile 2, which had 4 attributes of a location within 6-10 min, comfortable circumstances, a meal served with 4 side-dish and dessert and a meal price of \2,000 firstly, were recommend as new food service operation model.