• School Mathematics
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• v.18 no.4
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• pp.819-838
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• 2016

This research analyzed proportional reasoning abilities of the 5th grade students who learned only the basis of ratio and rate and 6th grade students who also learned proportion and cross product strategy. Data were collected through the proportional reasoning tests and the interviews, and then the achievement of the students and their proportional reasoning strategies were analyzed. In the light of such analytical results, the conclusions are as follows. Firstly, there is not much difference between 5th and 6th grade students in the achievement scores. Secondly, both 5th and 6th graders are less familiar with the geometric, qualitative and comparisons tasks than the other tasks. Thirdly, not only 5th graders but also 6th graders used informal strategies much more than the formal strategy. Fourthly, some students can't come up with other strategies than the cross product strategy. Finally, many students have difficulties in discerning proportional situation and non-proportional situations. This study provided suggestions for improving teaching proportional reasoning in elementary schools in Korea as follows: focusing on letting students use their informal strategies fluently in geometric, qualitative, and comparisons tasks as well as algebraic, quantitative, and missing value tasks focusing on the concept of ratio and proportion instead of enforcing the formal strategy.

• Journal of Elementary Mathematics Education in Korea
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• v.19 no.4
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• pp.457-484
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• 2015

This study aims to investigate an approach to teach proportional reasoning in elementary mathematics class by analyzing the proportional strategies the students use to solve the proportional reasoning tasks and their percentages of correct answers. For this research 174 sixth graders are examined. The instrument test consists of various questions types in reference to the previous study; the proportional reasoning tasks are divided into algebraic-geometric, quantitative-qualitative and missing value-comparisons tasks. Comparing the percentages of correct answers according to the task types, the algebraic tasks are higher than the geometric tasks, quantitative tasks are higher than the qualitative tasks, and missing value tasks are higher than the comparisons tasks. As to the strategies that students employed, the percentage of using the informal strategy such as factor strategy and unit rate strategy is relatively higher than that of using the formal strategy, even after learning the cross product strategy. As an insightful approach for teaching proportional reasoning, based on the study results, it is suggested to teach the informal strategy explicitly instead of the informal strategy, reinforce the qualitative reasoning while combining the qualitative with the quantitative reasoning, and balance the various task types in the mathematics classroom.

• Journal of the Korean Society of Food Science and Nutrition
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• v.35 no.10
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• pp.1484-1490
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• 2006

This study was carried out to prepare spaghetti sauce with adductor muscle of pearl oyster (SSAM) and to compare with commercial spaghetti sauce (CSS). From the results of organic acid, pH, hunter color value and sensory evaluation, the optimal addition ratio of adductor muscle of pearl oyster was 11% based for preparing SSAM and reasonable $F_0$ value was about 4 min for keeping storage of SSAM. The proximate composition of SSAM was 69.8% for moisture, 3.7% for protein, 4.2% for crude lipid and 3.4% for crude ash. SSAM was superior in sensory flavor and texture to CSS. There was, however, no significant difference (p<0.05) in sensory color between CSS and SSAM. The total amino acid content (3,033.4 mg/100 g) of SSAM was higher than that (2,305.7 mg/100 g) of CSS and the major amino acids were aspartic acid, glutamic acid, leucine and lysine. Calcium and phosphorus contents in SSAM were 48.5 mg/100 g and 27.1 mg/100 g, respectively. Calcium level based on phosphorous was 1.78, which was a good ratio for absorbing calcium. The free amino acid content and taste value of SSAM were 989.4 mg/100 g and 141.04 mg/100 g, respectively These results suggested that the major taste active compounds among free amino acid were glutamic acid and aspartic acid.

• Journal of Korean Ophthalmic Optics Society
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• v.14 no.1
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• pp.9-15
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• 2009

Purpose: The aim of this study is to examine various national standards and to suggest problems and improvements on KS (Korean Industrial Standards) in spectacle frames. Methods: We surveyed the latest published KS, ISO (International Organization for Standardization), JIS (Japanese Industrial Standards), DIN (Deutsches Institut fur Normung) and ANSI (American National Standards Institute) standards with relating spectacle frames. The titles that were considered in comparative study were terms and vocabulary, measuring system and terminology, marking, requirements and test methods, formers, screw threads, and others. Results: There were 9 different languages such as English (USA and UK), French, Russian, Japanese, Chinese, German, Italian and Spanish for the lists of equivalent terms and vocabulary in all standards except KS and ANSI, but gave an explanation for terms and vocabulary in only KS. Complementary terms and definitions were not existed in annex of KS and ANSI for measuring system and terminology, but they were included in annex of standards of the others. KS and ANSI standard for requirements and test methods differed from the ISO revision. Except JIS and ANSI, standards of formers were almost identical. KS standard of screw threads were similar to JIS. Standards of welded joints and nickel release did not exist in KS. Conclusions: All standards except ANSI tend to follow ISO, especially DIN is almost entirely identical to ISO. But KS is behind the times because it has been amended lately or established in accordance with older editions of ISO. Therefore, in order to assist quality control and safety for spectacle frames, KS standards shall be superseded by the specifications which is identical to ISO within a reasonable time.

• Journal of the Korean Institute of Gas
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• v.24 no.6
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• pp.47-54
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• 2020

A brittle fracture is one of the source of structural damage and can bring a fatal accident. The inner shell of LNG storage tank should be designed and applied to construction by ensure that no brittle crack will occur under -162℃ condition. In point of view of fracture mechanics brittle fracture in the structure could be referred as crack initiation and crack arrest. It should be designed no crack initiation. However, in the unlikely event of a brittle fracture occurring, a back-up function of arresting the brittle crack should be included for the design. In this paper investigated the characteristics of 9% Ni steel thick plates of having a capability of arresting brittle cracks under the thickness of 33 mm, 37mm, 40 mm. First, charpy test has performed to evaluate the fundamental brittle impact fracture property of 9% Ni steel under the temperature of 24℃, -162℃ and -196℃. In addition, Duplex ESSO tests were also performed under -196℃ to evaluate the capability of crack arrest for 9% Ni steel. From the experiments results, it was confirmed that all the thickness of 9% Ni steel plates exhibits sufficient brittle crack arrest fracture toughness for the application of LNG storage tank as a inner shell.

• Applied Biological Chemistry
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• v.44 no.4
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• pp.224-229
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• 2001

This study was carried out to examine the quality stability of powdered soup using powder from oyster wash water (PSW). To compare the quality stability, powdered soup from oyster hot-water extracts (PSE) was also prepared by mixing hot-water extract powder (15 g), table salt (5 g), cream powder (19 g), milk replacer (12 g), wheat flour (20 g), corn flour (15 g), starch (5 g), glucose (7.5 g), and onion powder (1.5 g). In preparing PSW, powder from oyster wash water, instead of powder from oyster hot-water extracts, was added and other additives were the same proportion as PSE. The PSW and PSE were packed with laminated film bag (OPP,$20\;{\mu}m$; PE, $20{\mu}m$; paper, $45\;g/m^3$; PE, $20\;{\mu}m$; Al, $7\;{\mu}m$; PE, $20\;{\mu}m$), and then stored at ambient temperature for 12 months. The moisture content, water activity, peroxide value, and fatty acid composition showed little changes during storage of the PSW, The pH, volatile basic nitrogen content, and brown pigment formation increased slightly, while white index decreased slightly during storage of PSW. No significant difference was observed in the changes of food components between PSW and PSE during storage. According to a sensory evaluation, the change in quality of PSW was negligible during 12 months of storage. From the results of the chemical experiment and sensory evaluation, PSW packed with laminated film bag (OPP, $20\;{\mu}m$; PE, $20\;{\mu}m$; paper, $45\;g/{\mu}m$; PE, $20\;{\mu}m$) was revealed to be preserved in good quality during 12 months of storage.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.175-182
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• 2009

Purpose : A number of countries have experienced an increase in pertussis during the past decade. In particular, there has been an increase in the incidence rate among adolescents and adults. To learn more about the current epidemiology of pertussis, we studied the prevalence and clinical characteristics of pertussis in children in Cheonan, South Korea. Methods : We collected nasopharyngeal aspirates of 118 patients who were treated for respiratory symptoms at Dankook Univeristy Hospital between March 2008 and September 2009. We performed multiplex PCR for detection of Bordetella pertussis in those aspirates. Results : Of the 118 patients, 10 (8%) were positive by PCR for B. pertussis. Six episodes occurred during the period July to September 2009. Nine of the 10 patients were less than 3 months old. Seven of them had not received DTaP vaccine. The mean duration of coughing before diagnosis was 10.9${\pm}$5.2 days. Ten patients (100%) had paroxysmal cough and 8 (80%) had post-tussive vomiting. Only one patient had fever. One who had complications that include pneumonia, atelectasis and pneumomediastinum developed an absolute increase in leukocyte count (84,400/$mm^3$). There was a statistically significant relation between vaccine being received and development of complications (P =0.033). Conclusion : We suspect that there was an epidemic of pertussis between July and September 2009. Further investigation by a pediatric or nationwide surveillance system is needed to monitor the changing epidemiology for pertussis.

• Journal of Veterinary Clinics
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• v.32 no.2
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• pp.168-173
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• 2015

This study estimated the degree of uterine inflammation and resumption of ovarian cyclicity in postpartum dairy cows. In addition, the prevalence of health problems during calving and the postpartum period was investigated. A total of 224 Holstein dairy cows from four dairy farms in Chungcheong Province were used for the study. Uterine discharge was scored on a 0 to 5 rank scale (metricheck score) using a metricheck instrument from 1 to 8 weeks postpartum and uterine cytology (neutrophil level) was examined at 4, 6 and 8 weeks postpartum to evaluate uterine inflammation. Resumption of ovarian cyclicity was evaluated based on progesterone analysis (${\geq}1ng/mL$) at 4, 6 and 8 weeks postpartum. Postpartum disorders were diagnosed by veterinarians in the research team. The metricheck score decreased linearly (p < 0.0001) from weeks 1 ($3.4{\pm}0.1$) to 4 ($2.0{\pm}0.1$) postpartum, and then remained at that level through week 8 postpartum ($1.6{\pm}0.1$, p > 0.05). The neutrophil levels determined by uterine cytology assays also decreased (p < 0.0001) from week 4 ($22.3{\pm}1.8%$) to 6 ($12.1{\pm}1.4%$) postpartum, and then remained at that level through week 8 postpartum ($9.2{\pm}1.4%$, p > 0.05). The proportion of cows exhibiting the ovarian cyclicity increased linearly (p < 0.0001) from weeks 2 (12.1%) to 8 (74.3%) postpartum. The prevalence of dystocia and retained placenta were 20.5% and 30.4%, respectively. The prevalence of ketosis, milk fever, abomasal displacement, septicemic metritis, endometritis, subclinical endometritis, pyometra, and ovarian cysts were 18.8%, 3.6%, 4.0%, 36.2%, 29.5%, 17.0%, 4.5%, and 14.7%, respectively. The prevalence of digestive problems and mastitis were 5.4% and 9.6%, respectively. The prevalence of culling and death were 4.0% and 3.6%, respectively. The prevalence of dystocia, retained placenta, septicemic metritis, endometritis, ovarian cysts, digestive problems, mastitis, and culling differed among farms (p < 0.05 to 0.01). In conclusion, proper examinations for uterine inflammation and ovarian cyclicity during 4 to 8 weeks postpartum are useful clinical tools to maintain herd reproductive health. Dystocia, retained placenta, septicemic metritis, and endometritis were predominant disorders in dairy cows of the survey area.

• Journal of the Korean Society of Radiology
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• v.13 no.3
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• pp.381-389
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• 2019

Although the development of Drug-eluting stent (DES) improved the ISR significantly more than the Bare metal stent (BMS), the coronary stent restenosis (ISR) treatment still has a high recurrence rate. This study is compared the efficacy of DEB with that of DES implantation in patients with ISR. Among 4,316 patients who underwent coronary stent implantation at the Chonnam National University Hospital between November 2012 and December 2016, 187 patients developed ISR on follow-up coronary angiography ($66.3{\pm}11.0years$, 123 males) were enrolled and divided into two groups according to revascularization method as group I (DEB group; n=127) and group II (DES group; n=60). Primary end point was defined as major adverse cardiac events (MACEs), composite of cardiac death (CD), myocardial infaction (MI), target lesion revascularization (TLR) and stent thrombosis (ST) during two-year follow-up between the two groups. There were no differences in the baseline characteristics and angiographic findings except that prevalence of device length was shorter ($21.1{\pm}5.3$ vs. $25.3{\pm}9.6 mm$, p<0.002) in group I.Two-year MACE were not different in the two groups (8.7%vs.10.0%, p=0.789). The incidences of cardiac death (0%vs.0%, p=1.000), MI (1.6%vs.6.7%, p=0.085), TLR(8.7% vs. 10.0%, p=0.789) and ST (0% vs. 0%, p=1000). DEB demonstrated comparable risk reduction for MACEs compared with DES in patients with ISR during two-year follow-up. DEB might be good alternative for the treatment of ISR in patients with ISR.

• Korean Journal of Food Science and Technology
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• v.42 no.3
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• pp.298-303
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• 2010

This study was carried out to compare the physicochemical characteristics of Korean traditional wine fermented from foxtail millet and nuruk at different mixing rates. The alcohol contents of fermented wine ranged from 12.70 to 13.38%. Two kinds of commercial nuruks, SH and BS nuruk, were used. The brix degrees of foxtail millet wine fermented by SH and BS nuruks were 21.6 and $22.4^{\circ}Bx$, respectively. The pH, total acidity, and turbidity of the wines fermented by SH and BS nuruks were 3.74 and 3.40, 1.40 and 1.51%, and 0.441 and 0.149, respectively. With an increase in the amount of foxtail millet, brix degree, pH, turbidity, b-value and L-value decreased, and total acidity and a-value increased. Total color difference (${\Delta}Eab$) parameter of the wine fermented by SH nuruk were 8.58, 22.59 and 22.55, while those by BS nuruk were 0.35, 4.08 and 7.16 in 30, 70 and 100% addition rates of foxtail millet, respectively. With an increase in the amount added of foxtail millet, glucose content decreased. The organic acids such as lactic acid and acetic acid were predominantly detected in the fermented wine. Finally, based on sensory evaluations, the wine fermented by BS nuruk showed the best overall quality at the 30% addition rate of foxtail millet.