• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.10 no.1
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• pp.31-37
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• 2005

To find out temporal variations of net photosynthetic rate (NPR) of intertidal flats, we measured oxygen microprofiles in sediments with oxygen microsensors 4 times from December 2003 to June 2004. The study areas were the intertidial flats in Janghwa-ri and Dongmak-ri, located on the southwestern and the southern parts of Ganghwa-gun, respectively, and in Incheon North Harbor where the content of organic matter was relatively high. During the investigation, oxygen penetration depths in the tidal flats of Janghwa-ri and Dongmak-ri were high in December (mean values of 4.0-4.1 mm). Thereafter, the oxygen penetration depths declined to mean values of 2.2-2.8 mm and 1.6-1.8 mm in the two tidal flats. Interestingly, the oxygen penetration depths in the Incheon North Harbor tidal flat showed a lower range $(0.8{\pm}0.3\;mm;\;mean{\pm}1SD)$ over the period. The maximum NPR in the Dongmak-ri tidal flat was found in March $(11.1{\pm}2.8\;mmol\;O_2\;m^{-2}\;h^{-1})$, and those In Janghwa-ri $(6.1{\pm}4.1\;mmol\;O_2\;m^{-2}\;h^{-1})$ and Incheon North Harbor $(6.4{\pm}1.4\;mmol\;O_2\;m^{-2}\;h^{-1})$ were observed in May. During the period when NPR was most active, the highest oxygen concentration was found at 0.1-0.5 mm depth below the surface sediment, and was on average 1.8-3.2 times higher than the air-saturated oxygen concentration in the overlying seawater. Although we took into account of low in situ light intensity $(400{\mu}Einst\;m^{-2}\;s^{-1})$ during the investigation in June, NPR in the 3 study areas decreased significantly to less than $0.2\;mmol\;O_2\;m^{-2}\;h^{-1})$. Thus, temporal variations of NPR were somewhat different among the tidal flats. Generally, benthic primary producers inhabiting in the uppermost 0.5 mm of the sediment showed a peak photosynthetic activity in the study areas in spring. This is the first domestic report on photosynthetic rates of benthic microflora in the tidal flats with oxygen microsensors, and the use of the microsensor can be widely applied to measurements of benthic primary production of a tidal flat and the oxygen consumption rate of surficial sediments.

• Korean Journal of Soil Science and Fertilizer
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• v.26 no.3
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• pp.143-150
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• 1993

To gain the basic informations on soil management practices by determination of the differences of soil genetic characteristics and the contents of soil moisture due to slope aspects of hilly land, this study was conducted at 1992 on sweet persimmon orchard soils derived from porphyry in southern of Korea. The results obtained were summarized as follows. The soils studied were belong to fine loamy family. The degree of soil development was greater in the north than other slope aspects and the solum thickness also the same. The soil chemical properties such as pH and exchangeable cations except for potassium were low generally in the orchards studied but the content of organic matter was lack in the summit and south aspect. The contents of Fe oxide and extractable Al were higher in the subsurface than surface. Fe, Al and clay indexes which indicate relative intensity of B horizon development were higher in the side slope than summit and the highest in the north slope. The rate of solum to B horizon was higher as about 1.5 for summit and west aspect which had thiner B horizon thickness compared to other aspect. North and west aspect had certainly more amount of soil water at drought season than other slope aspects and was lower the difference of soil water between the drought and wet seasons. Therfore, the soil management such as erosion control and irrigation at drought season should be practices differently due to slope aspect and soil chararteristics in the sloped land.

• Journal of Dental Rehabilitation and Applied Science
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• v.26 no.4
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• pp.405-417
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• 2010

Previous studies have already shown that mouthguard is effective in protecting jaw bone, teeth and oral tissue against sports trauma. However, other than severe trauma, repetitive force, such as disorders like clenching, cause teeth or oral tissue damage. These kinds of disorders usually present pathologic attrition in the posterior teeth, resorption in alveolar bone, loss of teeth and destruction of occlusion. Wearing a mouthguard is believed to be effective in preventing these disorders. But its effect is not examined thoroughly enough. The purpose of this study is to identify whether mouthguard is effective in reducing strain caused by clenching. Mandibular first molars in the normal occlusal relationship without any history of dental treatment were chosen. Biaxial type strain gauge was placed on the buccal surface of the tooth. Having maximum occlusal force, measured by load cell, as a standard, clenching intensity were divided into three stages; moment of slightly tooth contact, medium bite force (50% of maximum bite force), maximum bite force. Strain occurring in dentition in each stage with and without mouthguard was measured. Changes in strain (on dentition) between each stage and difference in strain, between with or without mouthguard were recorded by PCD-300 analyzer and PCD-30 soft ware. The data was statistically analyzed by Wilcoxon signed rank test. The following results were drawn; Without mouthguard, strain given on dentition increased as the clenching force increased. With mouthguard, strain given on dentition also increased as the clenching force increased. With mouthguard, strain decreased, in all cases of clenching force stages. Data on the moment of slightly tooth contact stage, had no statistical significance. However, with mouthguard, 50-90% of decrease in strain could be obtained in maximum occlusal force, compared to the group without mouthguard. Mouthguard decreased the strain on the dentition, caused by clenching. Therefore, mouthguard seems to be effective in preventing damage on dentition, by acting against clenching, which occurs both consciously and unconsciously during sports activities.

• Korean Journal of Environmental Agriculture
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• v.2 no.1
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• pp.45-54
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• 1983

This experiment was carried out to investigate effects of dense planting on the growth and productivity in varieties of hot pepper at open field. Three varieties (Joseng jinheung, Weonkyo No. 304 and Bulam house Putgochu) were sowed on Jan. 30th and transplanted on May 12th. The planting densities used were 3,300, 5,500 and 8,300 plants per 10a. The results obtained are as follows: 1) With higher plant density, the plant shape was changed from open-type to upright-type and the yield was increased, presumably due to the increase of leaf area index. 2) LAI and SLA per unit area were increased by denser planting. Wonkyo No. 304 presented the highest LAI and the lowest SLA. 3) Dry matter weight per unit area was also increased, however the LW/SW ratio was tended to decrease on denser planting. 4) Through crop growth analysis, it was determined that CGR and NAR were increased during the early growth stages and became decreased from last June. 5) Light intensity under the canopy formed by denser planting was decreased by 40% measured at 60 ㎝ above the soil surface. The vertical distribution of fruits became concentrated the upper part of plant. Fruit yield per unit area in denser planting was increased as compared to the conventional planting. The number of fruit setting decreased. 6) Generally, no differences in yield were detected in comparison between denser planting and conventional planting harvested on Aug. 30th and Oct. 15th, respectively. But Weonkyo No. 304 increased yield by 18% in denser planting.

• The Journal of Korean Society for Radiation Therapy
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• v.18 no.1
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• pp.1-5
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• 2006

Purpose: IMRT quality assurance(Q.A) is consist of the absolute dosimetry using ionization chamber and relative dosimetry using the film. We have in general used 0.015 cc ionization chamber, because small size and measure the point dose. But this ionization chamber is too small to give an accurate measurement value. In this study, we have examined the degree of calculated to measured dose difference in intensity modulated radiotherapy(IMRT) based on the observed/expected ratio using various kinds of ion chambers, which were used for absolute dosimetry. Materials and Methods: we peformed the 6 cases of IMRT sliding-window method for head and neck cases. Radiation was delivered by using a Clinac 21EX unit(Varian, USA) generating a 6 MV x-ray beam, which is equipped with an integrated multileaf collimator. The dose rate for IMRT treatment is set to 300 MU/min. The ion chamber was located 5cm below the surface of phantom giving 100cm as a source-axis distance(SAD). The various types of ion chambers were used including 0.015cc(pin point type 31014, PTW. Germany), 0.125 cc(micro type 31002, PTW, Germany) and 0.6 cc(famer type 30002, PTW, Germany). The measurement point was carefully chosen to be located at low-gradient area. Results: The experimental results show that the average differences between plan value and measured value are ${\pm}0.91%$ for 0.015 cc pin point chamber, ${\pm}0.52%$ for 0.125 cc micro type chamber and ${\pm}0.76%$ for farmer type 0.6cc chamber. The 0.125 cc micro type chamber is appropriate size for dose measure in IMRT. Conclusion: IMRT Q.A is the important procedure. Based on the various types of ion chamber measurements, we have demonstrated that the dose discrepancy between calculated dose distribution and measured dose distribution for IMRT plans is dependent on the size of ion chambers. The reason is small size ionization chamber have the high signal-to-noise ratio and big size ionization chamber is not located accurate measurement point. Therefore our results suggest the 0.125 cc farmer type chamber is appropriate size for dose measure in IMRT.

• Korean Journal of Food Science and Technology
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• v.42 no.1
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• pp.33-38
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• 2010

This study was conducted to compare the physicochemical properties of powdered green teas produced in Korea and Japan including particle size, color, chlorophyll, caffeine and theanine. The average particle size of Korean powered green tea ($14.63-25.39\;{\mu}m$) was similar to that of Japanese powdered green tea ($15.46-21.02\;{\mu}m$). The surface color of shade-cultivated Haenam Green Tea (HN-1) had the highest negative 'a' value, which represents 'green' color. When the TCD (total color difference value) was measured in the samples, HN-1 was most similar to the premium powdered green tea of Japan (JA-1). Domestic shade-cultivated powdered green teas had 1.5-2 times greater chlorophyll content than powdered green teas produced from plants that were not cultivated in the shade. The presence of chlorophyll a resulted in a higher intensity of green color than the presence of chlorophyll b. A significant negative correlation was also observed between the color and the chlorophyll a, chlorophyll b and total chlorophyll contents. Specifically, chlorophyll a had the greatest impact on the green color of powdered green tea. The content of catechins, caffeine and theanine in Korean powdered green teas ranged from 14.679-20.128, 1.496-3.237 and 0.926-1.977 g/100 g, respectively. The caffeine and theanine contents were high in shade-cultivated powdered green teas. Based on the above results, domestic powdered green teas cultivated under shaded conditions had a quality similar to that of medium-quality green teas produced in Japan, and the overall quality of Korean powdered green tea was poorer than that of Japanese powdered green tea.

• Journal of the Korean Magnetics Society
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• v.26 no.6
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• pp.219-225
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• 2016

In this study, for assessment of degenerative knee joint cartilage disease we acquired images by fat suppressed 3D spoiled gradient recalled (SPGR) and fat suppressed 3D $T2^*$ weighted imaging techniques. To do a quantitative evaluation, the knee joint cartilage was divided into medial femoral cartilage (MFC), medial tibial cartilage (MTC), lateral femoral cartilage (LFC), lateral femoral cartilage (LFC) and patella cartilage (Pat) to measure their respective signal intensity values, signal-to-noise ratio, and contrast-to-noise ratio. As for the measured values, statistical significance between two techniques was verified by using Mann-Whitney U-Test. To do a qualitative evaluation, two radiologists have examined images by techniques after which image artifact, cartilage surface, tissue contrast, and depiction of lesion distinguishing were evaluated based on 4-point scaling (1: bad, 2: appropriate, 3: good, 4: excellent), and based on the result, statistical significance was verified by using Kappa-value Test. 3.0T MR system and HD T/R 8ch knee array coil were used to acquire images. As a result of a quantitative analysis, based on SNR values measured by using two imaging techniques, MFC, LFC, LTC, and Pat showed statistical significance (p < 0.05), but MTC did not (p > 0.05). As a result of verifying statistical significance for measured CNR value, MFC, LFC, and Pat showed statistical significance (p < 0.05), while MTC and LTC did not show statistical significance (p > 0.05). As a result of a qualitative analysis, by comparing mean values for evaluated image items, 3D $T2^*$ weighted Image has indicated a slightly higher value. As for conformance verification between the two observers by using Kappa-value test, all evaluated items have indicated statistically significant results (p < 0.05). 3D $T2^*$ weighted technique holds a clinical value equal to or superior to 3D SPGR technique with respect to evaluating images, such as distinguishing knee joint cartilages, comparing nearby tissues contrast, and distinguishing lesions.

• Journal of the Korean Geographical Society
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• v.40
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• pp.1-13
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• 1989

The brightness temperature from NOAA AVHRR CH 4 images was examined for the metropolitan Seoul area, the capital city of Korea, to detect the characteristics of the urban heat island for this study. Surface data from 21 meteorological stations were compared with the brightness temperatures Through computer enhancement techniques, more than 20 heat islands could be recognized in South Korea, with 1 km spatii resolution at a scale of 1: 200, 00O(Fig. 3, 4 and 6). The result of the analysis of AVHRR CH 4 images over the metropolitan Seoul area can be summerized as follows (1) The pattern of brightness temperature distribution in the metropolitan Seoul area shows a relatively strong temperature contrast between urban and rural areas. There is some indication of the warm brightness temperature zone characterrizing built-up area including CBD, densely populated residential district and industrial zone. The cool brightness temperature is asociaed with the major hills such as Bukhan-san, Nam-san and Kwanak-san or with the major water bodies such as Han-gang, and reservoirs. Although the influence of the river and reservoirs is obvious in the brightness temperauture, that of small-scaled land use features such as parks in the cities is not features such as parks in the cities is not apperent. (2) One can find a linerar relationshop between the brightenss temperature and air temperature for 10 major cities, where the difference between two variables is larger in big cities. Though the coefficient value is 0.82, one can estimate that factors of the heat islands can not be explained only by the size of the cities. The magnitude of the horizontal brightness temperature differences between urban and rural area is found to be greater than that of horizontal air temperature difference in Korea. (3) Also one can find the high heat island intensity in some smaller cities such as Changwon(won(Tu-r=9.0$^{\circ}$C) and Po-hang(Tu-r==7.1$^{\circ}$~)T. he industrial location quotient of Chang-won is the second in the country and Po-hang the third. (4) A comparision of the enhanced thermal infrared imageries in 1986 and 1989, with the map at a scale of 1:200, 000 for the meotropolitan Seoul area showes the extent of possible urbanization changes. In the last three years, the heat islands have been extended in area. zone characterrizing built-up area including (5) Although the overall data base is small, the data in Fig. 3 suggest that brightness tempeautre could ge utilized for the study on the heat island characteristics. Satellite observations are required to study and monitor the impact of urban heat island on the climate and environment on global scale. This type of remote sensing provides a meams of monitoring the growth of urban and suburban aeas and its impact on the environment.

• Culinary science and hospitality research
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• v.21 no.1
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• pp.77-89
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• 2015

The objective of this study was to optimize processing conditions for the production of an instant puffed rice product using response surface methodology (RSM) and contour analysis. Sensory and texture qualities, and physical properties of the puffed rice were analyzed with various processing conditions related to drying and puffing temperature, and moisture content. Preference, color intensity, cohesiveness, rehydration ratio, density and lightness of the puffed rice product significantly varied depending on the processing conditions. The responses showed high $R^2$ values (0.623, 0.852, 0.735, 0.688, and 0.790) and lack-of-fit. Rehydration ratio was found to have a negative correlation with density in the condition of drying and puffing temperature. Lightness and preference scores of the puffed rice increased as the moisture content increased. According to RSM, the preference scores were very highly related to the moisture content, and the optimum processing conditions of the puffed rice product were at $40^{\circ}C$ of drying temperature, with 11.0% of moisture content, and at $232.7^{\circ}C$ of puffing temperature.

• Restorative Dentistry and Endodontics
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• v.32 no.4
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• pp.377-384
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• 2007

Present tooth bonding system can be categorized into total etching bonding system (TE) and self-etching boding system (SE) based on their way of smear layer treatment. The purposes of this study were to compare the effectiveness between these two systems and to evaluate the effect of number of themocycling on microleakage of class V composite resin restorations. Total forty class V cavities were prepared on the single-rooted bovine teeth and were randomly divided into four experimental groups: two kinds of bonding system and another two kinds of thermocycling groups. Half of the cavities were filed with Z250 following the use of TE system, Single Bond and another twenty cavities were filled with Metafil and AQ Bond, SE system. All composite restoratives were cured using light curing unit (XL2500, 3M ESPE, St. Paul, MN, USA) for 40 seconds with a light intensity of $600mW/cm^2$. Teeth were stored in distilled water for one day at room temperature and were finished and polished with Sof-Lex system. Half of teeth were thermocycled 500 times and the other half were thermocycled 5,000 times between $5^{\circ}C$ and $55^{\circ}C$ for 30 second at each temperature. Teeth were isolated with two layers of nail varnish except the restoration surface and 1 mm surrounding margins. Electrical conductivity (${\mu}A$) was recorded in distilled water by electrochemical method. Microleakage scores were compared and analyzed using two-way ANOVA at 95% level. From this study, following results were obtained: There was no interaction between variables of bonding system and number of thermocycling (p = 0.485). Microleakage was not affected by the number of thermocycling either (p = 0.814). However, Composite restoration of Metafil and AQ Bond, SE bond system showed less microleakage than composite restoration of Z250 and Single Bond, TE bond system (p = 0.005).