• Journal of the Korean Geographical Society
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• v.29 no.4
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• pp.438-449
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• 1994

This paper focuses on recontextualizing geography curriculum, i.e. examining recent changing aspects in three geography curriculum locators-society, student and discipline of geography-and searching future directions of geography curriculum in light of such changes. For conciliation and reflection of changing aspects of each locators, this paper dealt with social issues and societal changes in terms of locator of society, increased concern to student and development of cognitive science in terms of students, and challenging views on science and the meaning of epistemological changes in geography in terms of discipline. As a result, three future directions in geography curriculum are searched : issue-based geography curriculum, thinking geography curriculum, geography curriculum toward equity and accessbility.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.33 no.2
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• pp.152-161
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• 2007

This study was conducted to patients visited oral maxillo-facial surgery, KNUH and the purpose of the study was to assess skeletal and dento-alveolar stability after surgical-orthodontic correction treated by skeletal Class III malocclusion patients with open bite versus non-open bite. This retrospective study was based on the examination of 40 patient, 19 males and 21 females, with a mean age 22.3 years. The patients were divided into two groups based on open bite and non-open bite skeletal Class III malocclusion patients. The cephalometric records of 40 skeletal Class III malocclusion patients (open bite: n = 18, non-open bite: n = 22) were examined at different time point, i.e. before surgery(T1), immediately after surgery(T2), one year after surgery(T3). Bilateral sagittal split ramus osteotomy was performed in 40 patients. Rigid internal fixation was standard method used in all patient. Through analysis and evaluation of the cephalometric records, we were able to achieve following results of post-surgical stability and relapse. 1. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in maxillary occlusal plane angle of pre-operative stage(p>0.05). 2. Mean vertical relapses of skeletal Class III malocclusion patients with open bite were $0.02{\pm}1.43mm$ at B point and $0.42{\pm}1.56mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.12{\pm}1.55mm$ at B point and $0.08{\pm}1.57mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in vertical relapse(p>0.05). 3. Mean horizontal relapses of skeletal Class III malocclusion patients with open bite were $1.22{\pm}2.21mm$ at B point and $0.74{\pm}2.25mm$ at Pogonion point. In skeletal Class III malocclusion patients with non-open bite, $0.92{\pm}1.81mm$ at B point and $0.83{\pm}2.11mm$ at Pogonion point. There was no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in horizontal relapse(p>0.05). 4. There were no significant statistical differences between open bite and non-open bite with skeletal Class III malocclusion patients in post-surgical mandibular stability(p>0.05). and we believe this is due to minimized mandibular condylar positional change using mandibular condylar positioning system and also rigid fixation using miniplate 5. Although there was no significant relapse tendency observed at chin points, according to the Pearson correlation analysis, the mandibular relapse was influenced by the amount of vertical and horizontal movement of mandibular set-back(p=0.05, r>0.304).

• The Journal of Korean Academy of Prosthodontics
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• v.50 no.2
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• pp.92-98
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• 2012

Purpose: The aim of this study was to evaluate the effects of different abutment materials on abutment screw loosening and settling-down effect in conical connection type implant system. Materials and methods: Three types of abutment, cementation, gold UCLA, and metal UCLA abutment were used. Two UCLA groups were fabricated in a similar pattern to cementation abutment. Type III gold alloy and Nickel-Chromium alloy was used for casting gold UCLA abutment and metal UCLA abutment, respectively. Fixture and abutment were tightened to 30 Ncm by using digital torque controller and re-tightening was conducted with same force after 10 minutes. Digital torque gauge was used to measure loosening torque and fixture/abutment length was measured by digital micrometer. Dynamic loads between 25 N and 250 N were applied with $0^{\circ}$ angle to the abutment axis. After loading, fixture/abutment length was re-measured and amount of settlement was calculated. Loosening torque value was also measured for comparison Results: All three groups showed significant differences of length when comparing before and after loading, but there was no significant difference of settling amount in all groups. Loosening torque values were significantly decreased when comparing before and after loading in all groups($P$<.05). However, there was no significant difference in loss of loosening torque values when compared to groups. Conclusion: In internal conical connection type implants, dynamic load affected on settlement and loosening torque of implant, but there was no differences between abutments materials. Likewise gold UCLA abutment, metal UCLA abutment might be able to withstand functional load.

• Journal of the Korean Ceramic Society
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• v.38 no.10
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• pp.908-913
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• 2001

Paper sludge Ash (PA) and Fly Ash (FA) wastes are usually land-filled for reclamation or substituted for cements as a resource. It could also offer some advantages when they are substituted for clay to preserve the environment. To recycle those wastes, the sintered specimen made of PA-FA-Clay system were examined to find the microstructure and physical properties. The ratio of clay to wastes was fixed as 30:70 by wt%, while PA to FA within waste portion were varied in the range of $1:6{\sim}7:0$. Those specimens were fired in $1150{\sim}1350^{\circ}C$. It was found that the relative density of sintered specimen was increased with amount of PA added at low sintering temperature (i.e, $1150{\sim}1200^{\circ}C$). This is due to increased amount of liquid during sintering. It is shown, however that at high sintering temperature ($1250{\sim}1350^{\circ}C$), the relative density of specimens was decreased with amount of PA added. This is because of overfiring phenomenon which may be able to induce an inhomogeneous microstructure and increased porosity. The mechanical properties of sintered specimen were depended upon the homogeneity of microstructure in accordance with SEM (Scanning Electron Microscopy) and pore size distribution analysis. For example, the compressive strength of 10PA-60FA-30Clay specimen sintered at $1225^{\circ}C$ was twice higher than that of 70PA-30Clay specimen even thought the relative density of those specimen was similar. This decreased strength of 70PA-30Clay specimen appears to be an inhomogeneity of microstructure due to overfiring.

• Journal of Bio-Environment Control
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• v.29 no.3
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• pp.239-244
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• 2020

Effect of 6kg large unit with the carton box (20% open ratio) and MA box (10,000cc·m^-2·day^-1·atm^-1 oxygen transmission rates modified atmosphere package), and the 100g small unit with MA film on asparagus sensory quality were evaluated. The CO₂ concentration depended largely on the packing unit and maintained at around 3% in small MA packages, whereas in the MA box increased to 12%. Ethylene concentration rapidly increased until after 3 days of storage in MA packages and then decreased to maintain 5μL·L^-1. Unrelated to the unit size, the lower weight loss was obtained in MA packages. A significant difference in visual quality was shown since the 15th day, the best and worst were the MA box and small MA package on the finish day. Off-odor was the highest in small MA packages and the lowest in the carton box (< 3.0). Although there was no significant difference in firmness among all treatments, the packages showed the highest firmness in tips and stems, respectively. The sugar content and hue angle decreased during storage, but there was no statistical difference in all treatments. EL was lowest and highest in small MA package and carton box, respectively. On the 10th day, the total aerobic bacteria was lowest in small MA packages, but no significant difference on the 20th day. E. coli was not found in all treatments on the 10th day, while it was the lowest in the MA box on the 20th day. The mold and yeast were not observed during the whole storage. Based on the above results, the carton box packaged with 10,000cc OTR film was more effective in maintaining the quality of green asparagus with the suitable CO₂ concentration for asparagus cold storage.

• Korean journal of applied entomology
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• v.39 no.3
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• pp.135-140
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• 2000

Development and reproduction of the cotton caterpillar, Palpita indica, were investigatedunder different temperatures (15 .O, 17.5, 20.0, 22.5, 25 .O, 27.5, 30.0, 32.5, and 35 .O$^{\circ}$C). Duration fromegg to pre-adult of the cotton caterpillar were ranged from 68.6 days at 175$^{\circ}$C to 19.7 days at 35.0% (3.5times shorter growth period compared with that at 17S$^{\circ}$C). At 15.0$^{\circ}$C, cotton caterpillar eggs developedto the last larval instar but were not able to go through the pupal stage. The lower developmentalthreshold temperatures and degree-days of egg, larva, pupa, and complete development were 13.4, 10.6,11.6, and 11.5"C and 55.3,251.5, 138.3, and 479.8 degree days, respectively. The hatching, pupation andemergence rates were higher at 25.0eC and 27.5"C compared with other temperatures. The survival ratefrom the hatched larva to adult was the highest at 27.5"C. The preoviposition and the adult longevity were11.5 and 30.6 days at 17.5"C and 1.5 and 9.2 days at 35.0$^{\circ}$C, respectively. The mean fecundity perfemales was greater at 25.0$^{\circ}$C and 27.5"C compared with other temperatures. Mean generation time indays (T) was shorter on higher temperature. Net reproductive rate per generation (R,) was the lowest atthe highest temperature as well as at the lowest, and it was 199.1 which was the highest at 27.5"C. Theintrinsic rate of natural increase (r,) was highest at 30.0$^{\circ}$C as 0.148. As a result, optimum ranges oftemperature for P. indica growth were between 25.0-32.5"C .emperature for P. indica growth were between 25.0-32.5"C .t;C .

• Progress in Medical Physics
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• v.13 no.4
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• pp.209-217
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• 2002

There have been many studies on the application of the reciprocal advantages of multimodality image to define accurate target volume in the Process of radiation treatment planning. For the proper use of the multimodality images, the registration works between different modality images should be performed in advance. In this study, we selected chamfer matching method and mutual information method as most popular methods in recent image registration studies considering the registration accuracy and clinical practicality. And the two registration methods were analyzed to deduce the optimal registration method according to the characteristics of images. Lung phantom of which multimodality images could be acquired was fabricated and CT, MRI and SPECT images of the phantom were used in this study. We developed the registration program which can perform the two registration methods properly and analyzed the registration results which were produced by the developed program in many different images' conditions. Although the overall accuracy of the registration in both chamfer matching method and mutual information method was acceptable, the registration errors in SPECT images which had lower resolution and in degraded images of which data were removed in some part were increased when chamfer matching method was applied. Especially in the case of degraded reference image, chamfer matching methods produce relatively large errors compared with mutual information method. Mutual information method can be estimated as more robust registration method than chamfer matching method in this study because it did not need the prerequisite works, the extraction of accurate contour points, and it produced more accurate registration results consistently regardless of the images' characteristics. The analysis of the registration methods in this study can be expected to provide useful information to the utilization of multimodality images in delineating target volume for radiation treatment planning and in many other clinical applications.

• Korean journal of applied entomology
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• v.41 no.4
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• pp.269-277
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• 2002

Ecological studies on entomopathogenic nematodes are required to increase control efficacy against target insect pests and to obtain basic information for mass production. Thus, effect of temperature and nematode concentration on infectivity and reproduction of Steinernema carpocapsae Pocheon and that of exposure time and soil depth on infectivity were examined using Galleria mellonella larvae. Infectivity and reproduction were examined at five temperatures, 13, 18, 24, 30 and 35$^{\circ}C$ with seven concentrations, 0, 5, 10, 20, 40, 80 and 160 infective juveniles (IJs)/larva. Temperature and nematode concentration influenced infectivity and reproduction of S. carpocapsae Pocheon. Although G. mellonella larvae were killed by S. carpocapsae Pocheon at all given temperatures and nematode concentrations, mortality was higher at 24$^{\circ}C$ than other temperatures. Lethal time of G. mellonella by S. carpocapsae Pocheon was shorter with increasing temperature and nematode concentrations. S. carpocapsae Pocheon was not established in G. mellonella at 13 and $35^{\circ}C$. Time for the first emergence from G. mellonella cadaver was longer $18^{\circ}C$ (about 20 days) than 24 and $30^{\circ}C$ (about 5 days). The highest number of progenies was obtained at $24^{\circ}C$ with 80IJs/1arva, i.e., $18.8$\times$10^4$IJs were produced from a larva. In the exposure time assay, G. mellonella death was recorded in 10 minutes when 300 IJs were inoculated per larva. When S. carpocapsae Pocheon was inoculated at the rate of $10^{9}$ IJs/ha to G. mellonella at the depth of 0, 2, 5 and 10 cm of sand columns, 100% mortality and similar sex ratio were observed but number of established IJs in cadaver was decreased with deepening the soil depth. The results indicated that optimum temperature for infectivity and reproduction of S. carpocapsae Pocheon was $24^{\circ}C$ In addition, S. carpocapsae Pocheon was effective to target insects within 5 cm from the soil surface.

• Journal of the Korean Society for Marine Environment & Energy
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• v.9 no.4
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• pp.243-252
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• 2006

Influence of the increasing carbon dioxide concentration in seawater on various marine organisms is assessed in this article with regard to the impacts of anthropogenic $CO_2$ introduced into surface or deep oceans. Recent proposals to sequester $CO_2$ in deep oceans arouse the concerns of adverse effects of increased $CO_2$ concentration on deep-sea organisms. Atmospheric introduction of $CO_2$ into the ocean can also acidify the surface water, thereby the population of some sensitive organisms including coral reefs, cocolithophorids and sea urchins will be reduced considerably in near future (e.g. in 2100 unless the increasing trend of $CO_2$ emission is actively regulated). We exposed bioluminescent bacteria and benthic amphipods to varying concentrations of $CO_2$ and also pH for a short period. The ${\sim}l.5$ unit decrease of pH adversely affected test organisms. However, amphipods were not influenced by decreasing pH when HCl was used for the seawater acidification. In this article, we reviewed the biological adverse effects of $CO_2$ on various marine organisms studied so for. Theses results will be useful to predict the potential risks of the increase of $CO_2$ concentrations in seawater due to the increase of atmospheric $CO_2$ emission and/or sequestration of $CO_2$ in deep oceans.

• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.2
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• pp.203-214
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• 2018

Ballast water treated by sodium dichloroisocyanurate (NaDCC) injection method in ballast water management system (BWMS) contains reactive bromine, chlorine species and disinfection by-products (DBPs). In this study, we conducted whole effluent toxicity (WET) testing and ecological risk assessment (ERA) to investigate its ecotoxicological effects on the marine environment. WET testing was carried out for eight marine and fresh water organisms, i.e. diatom, Skeletonema costatum, Navicula pelliculosa, green algae, Dunaliella tertiolecta, Pseudokirchneriella subcapitata, rotifer, Brachionus plicatilis, Brachionus calyciflorus and fish, Cyprinodon variegatus, Pimephales promelas. The WET test revealed that diatom and green algae were the only organisms that showed apparent toxicity to the effluent; it showed no observed effect concentration (NOEC), lowest observable effect concentration (LOEC) and effect concentration of 50 % (EC50) values of 25.0 %, 50.0 % and over 100.0 %, respectively, in seawater conditions. In contrast, rotifer and fish showed no toxicities to the effluent in the all salinity conditions. Meanwhile, chemical analysis revealed that the BWMS effluent contained total of 25 DBPs such as bromate, isocyanuric acid, formaldehyde, chloropicrin, trihalomethanes (THMs), halogenated acetonitriles (HANs) and halogenated acetic acids (HAAs). Based on ERA, the 25 DBPs were not considered to have persistency, bioaccumulation and toxicity (PBT) properties. The ratio of predicted environmental concentration (PEC) to predicted no effect concentration (PNEC) of the all DBPs did not exceed 1.0 for general harbour environments, but isocyanuric acid, tribromomethane, chloropicrin and monochloroacetic acid exceed 1.0 for near ship environments. However, when NOEC (25.0%) of the WET test results where actual effluent was applied, it was concluded that the NaDCC injection method did not have unacceptable ecological risks to the general harbor including near ship environments.