• Korean Journal of Ecology and Environment
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• v.47 no.4
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• pp.312-318
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• 2014

This study was conducted to establish models of filtrating rate and production of feces of a native freshwater bivalve, Anodonta woodiana, on removal organic matters in eutrophic waters. Among the applied shell size (4.3~15.5 cm), the filtrating rate and production of feces of Anodonta woodiana was $0.08{\sim}0.86L\;g^{-1}\;h^{-1}$ (average $0.24L\;g^{-1}\;h^{-1}$), $0.00{\sim}11.10mg\;g^{-1}\;h^{-1}$ (average $0.94mg\;g^{-1}\;h^{-1}$), respectively. In two different water current (high $48Lh^{-1}$, low $24Lh^{-1}$), the filtrating rate of Chl-a was $0.02{\sim}0.10L\;g^{-1}\;d^{-1}$ (average $0.05L\;g^{-1}\;d^{-1}$), $0.02{\sim}0.11L\;g^{-1}\;d^{-1}$ (average $0.07L\;g^{-1}\;d^{-1}$) and the removal rate was 65.4%, 82.1%, respectively. Response surface methodology, with a central composite design comprising 3 levels and 2 variables, was used to identify the optimal removal condition of shell length, water current and filtrating rate or feces production by bivalves. The optimum removal conditions were found that had optimized $6.21L\;mussel^{-1}\;d^{-1}$ at shell length 14.3~15.6 and water current $22{\sim}30Lh^{-1}$. The optimal conditions of production of feces ($4.2mg\;g^{-1}\;d^{-1}$) by freshwater mussels were shell length 14.3~16.3 cm and water current $36{\sim}44Lh^{-1}$.

• Journal of dental hygiene science
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• v.13 no.1
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• pp.97-104
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• 2013

This study investigated the safety management behavior of dental professionals to minimize exposure to harmful elements of amalgam and resin. As for the use of amalgam and resin, 85.8% of them used amalgam. 100% of used composite resin 100%. 97.8% used acryl resin, and 95.7% used tray resin. 95.2% and 36.5% of them were aware of the harm of amalgam and resin respectively. When using resin, their safety management behavior score was 1.99 on average, and the lowest score was 2.50 on average for 'ventilate the indoor air when handling resin'. Their average score of the safety management behavior was 1.83 when using amalgam. The lowest score was 2.89 on average for 'use the rubber dam for patients when handling amalgam'. As a result of the safety management behavior based on general characteristics, all characteristics were significant with regard to amalgam, and my position at work and work experience were significant with regard to resin (p<0.05). The correlation between the safety management behavior and general characteristics was analyzed when dental amalgam and resin are used. Amalgam was statistically correlated with academic background (p<0.05) and position at work (p<0.05), whereas resin was statistically significantly correlated with age (p<0.05) and position at work (p<0.05). Accordingly, education about the harm of dental materials must be continuously provided for dental professionals when they handle dental materials so that safety management behavior will be conducted correctly, and active efforts to protect the health of dental professionals from harmful chemicals must be made.

• Journal of Energy Engineering
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• v.23 no.4
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• pp.88-94
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• 2014

In this paper, Thermal Shock tests were performed varying the composition of the solder and ribbon thickness (A-type:0.2mm/60Sn40Pb, B-type:0.25mm/60Sn40Pb, C-type:0.2 /62Sn36Ag2Pb, D-type:0.25mm/62Sn36Ag2Pb) for evaluating the long-term reliability about Ribbon junction of Silicon solar cells. Thermal Shock test condition was performed during the 600cycles having $-40^{\circ}C{\sim}85^{\circ}C$ temperature range each 15 minutes; One cycle time was 30min. As a result, the initial efficiency of the A-type, B-type, and C, D-type were showed 15.0%, 15.4% and 15.8% respectively. After thermal shock test, the efficiency decreasing-rate of each type were as follow that A-type was 13.8%, B-Type was 15.4%. C-Type and D-Type was 15.3% and 16.2%, respectively. Also, degradation of surface changes and I-V characteristic curves were showed that the series resistance of the A, C-type was increased. Also, current lowering starting point of C-type shown 0.05volt[v] earlier than that of A-type. And B, D-type shown characteristics of composite lowering efficiency such as increase of series resistance, decrease of parallel resistance and cell damage. Therefore Initial solderability and efficiency of specimens using the solder with SnAgPb were superior. But, It has inferior the long-term reliability. The test was confirmed that as the ribbon thickness increases, long-term reliability of solar cell will decrease.

• Radiation Oncology Journal
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• v.20 no.2
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• pp.165-171
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• 2002

Purpose : In order to perform craniospinal irradiation (CSI) in the supine position on patients who are unable to lie in the prone position, a new simulation technique using a CT simulator was developed and its availability was evaluated. Materials and Method : A CT simulator and a 3-D conformal treatment planning system were used to develop CSI in the supine position. The head and neck were immobilized with a thermoplastic mask in the supine position and the entire body was immobilized with a Vac-Loc. A volumetrie image was then obtained using the CT simulator. In order to improve the reproducibility of the patients' setup, datum lines and points were marked on the head and the body. Virtual fluoroscopy was peformed with the removal of visual obstacles such as the treatment table or the immobilization devices. After the virtual simulation, the treatment isocenters of each field were marked on the body and the immobilization devices at the conventional simulation room. Each treatment field was confirmed by comparing the fluoroscopy images with the digitally reconstructed radiography (DRR)/digitally composite radiography (DCR) images from the virtual simulation. The port verification films from the first treatment were also compared with the DRR/DCR images for a geometrical verification. Results : CSI in the supine position was successfully peformed in 9 patients. It required less than 20 minutes to construct the immobilization device and to obtain the whole body volumetric images. This made it possible to not only reduce the patients' inconvenience, but also to eliminate the position change variables during the long conventional simulation process. In addition, by obtaining the CT volumetric image, critical organs, such as the eyeballs and spinal cord, were better defined, and the accuracy of the port designs and shielding was improved. The differences between the DRRs and the portal films were less than 3 mm in the vertebral contour. Conclusion : CSI in the supine position is feasible in patients who cannot lie on prone position, such as pediatric patienta under the age of 4 years, patients with a poor general condition, or patients with a tracheostomy.

• Korean journal of food and cookery science
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• v.29 no.6
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• pp.661-669
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• 2013

This study was performed to determine the optimal composition of Cheonggukjang added with garlic. The experiment utilized a central composite design (CCD). The evaluation was carried out by means of response surface methodology (RSM), which included 18 experimental points with three independent variables : the content of the garlic (1.3~9.7%, $X_1$), the steaming time of garlic (0~15.1 min, $X_2$), and the fermentation time of Cheonggukjang (48.2~71.8 h, $X_3$). The viscous substance ($Y_1$), acidity ($Y_2$), amino-type nitrogen ($Y_3$), ${\gamma}$-GTP activity ($Y_4$) and ABTS radical scavenging activity ($Y_5$). were assessed in four replicates with five dependent variables. The maximum content of the viscous substance was 13.02% at 6.53% ($X_1$), 6.81 min ($X_2$) and 55.18 h ($X_3$). The acidity was increased when the fermentation time was longer, and the minimum acidity point was 0.50% at 7.75% ($X_1$), 3.42 min ($X_2$) and 58.60 h ($X_3$), respectively. The content of the amino-type nitrogen at the experimental range studied was was 80.58~158.82 mg%, and the stationary point was at saddle point. Using ridge analysis, the maximum point was 156.97 mg% at 6.21% ($X_1$), 14.85 min ($X_2$) and 58.04 h($X_3$). The optimum conditions of ${\gamma}$-GTP activity was 5.73% ($X_1$), 6.99 min ($X_2$) and 57.96 h($X_3$), respectively, at the maximum point was 353.66 mU/mL. The maximum point of ABTS radical scavenging activity was 76.43% at 3.78% ($X_1$), 14.28 min ($X_2$) and 57.99 h($X_3$) at the saddle point, when the garlic steaming time was longer.

• Journal of agricultural medicine and community health
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• v.28 no.2
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• pp.1-14
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• 2003

Objectives: This paper introduces need and supply level of rural mental health care service and especially focuses on the evaluation for the community mental health programs of Public Health Centers(PHCs) in rural areas as the facilities for primary mental health care. Methods: We defined the need as prevalance rate and service utilization rate, for which reviewed the results of the epidemiological study of mental disorders using Korean Composite International Diagnostic Interview surveyed on a nationwide scale in 2001. Supply was appraised in terms of psychiatric beds and primary mental heath care facilities such as private psychiatric clinics, facilities for social rehabilitation, PHCs running community mental health programs. For this, we reveiwed a variety of annual reports related mental health published by Ministry of Health and Welfare. To evaluate the community mental health programs of PHCs in rural areas, we selected. randomly samples out of the 3rd community health plans including the contents of community mental health programs, which submitted by 89 rural counties and 44 cities mixed with rural areas, and used the program's guideline established by central government as a standard. Results: Prevalence rates of major psychiatric diseases such as schizophrenia, alcoholism, major depression, anxiety disorder were higher in rural area than in urban area and 8.9% of psychiatric patients in both areas stayed at homes contacted with mental health manpower more than one time during the last year. Psychiatric beds were sufficiently supplied, but urban area had less beds than rural area contrary to general health care service. Psychiatric clinics were supplied very insufficiently in rural areas and PHCs bridged the gap instead. However rural PHCs got less financial support for community mental health programs from higher positioned agencies than urban PHCs. Rural community health programs not supported hardly worked out. Conclusions: Central government should consider a special policy for rural primary mental health care, because private psychiatric clinics can't be introduced in rural areas due to demand-deficiency and the financial independence of rural counties was very vulnerable.

• The Journal of Korean Academy of Prosthodontics
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• v.42 no.5
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• pp.514-523
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• 2004

Statement of problem: All-ceramic restorations have been advocated for superior esthetics. Various post and core systems have been used to improve the strength of damaged teeth, but it is unclear whether they affect the final shade of finished all-ceramic restorations. Purpose: The influence of different types of post and core systems on light transmission through all-ceramic crowns was assessed by spectrophotometric analysis. Also the masking effect of different thickness of ceramic ingot was evaluated. Material and Methods : Forty-five sample disks (15mm in diameter) at several thickness(1.0, 1.5, 2.0mm) and value(shade 100, 200, 300) were made in heat pressed ceramic(IPS-Empress). Background specimens simulating gold-alloy cast posts(Type III casting gold alloy), metal posts(Ni-Cr casting alloy) and ceramic posts(CosmoPost) were fabrica-ted. Resin composite(Z250, A3 shade) was used as a tooth substrate reference. For each combination, the change in color was measured with a spectrophotometer. Readings were performed for 2 conditions (1) ability of ceramic to mask the core in relation to its thickness(1.0, 1.5, or 2.0mm) ; (2) influence of post and core types on the final color of the ceramic. Data were recorded according to the CIE $L^*a^*b^*$ systems and color difference($\Delta$E) was calculated. Results: 100 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post larger than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5mm, only $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 2. 200 shade ingot: when ceramic thickness was 1.0mm, $\Delta$E value for ceramic post was smaller than 1 but $\Delta$E value for metal and gold post was larger than 2. For ceramic thickness of 1.5 mm, only the $\Delta$E value for metal was larger than 2, and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. 300 shade ingot: when ceramic thickness was 1.0mm, only $\Delta$E value for metal was larger than 2 and the other samples' $\Delta$E value was smaller than 2. For ceramic thickness of 1.5mm, $\Delta$E values for all specimens was smaller than 1. For ceramic thickness of 2.0mm, $\Delta$E values for all specimens was smaller than 1. Conclusion: The final esthetic result of the IPS-Empress glass-ceramic restoration was not affected by the presence of different core materials when the thickness was more than 2.0 mm. When ceramic thickness decreases to 1.5mm, it is advised to take the substrate aspects into consideration. If the ceramic thickness is less than 1.0mm, using the tooth color matched substrate is strongly recommended.

• The Journal of Korean Academy of Prosthodontics
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• v.46 no.1
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• pp.1-11
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• 2008

Statement of problem: Over the past decade, increased demand for esthetically pleasing restorations has led to the development of all-ceramic systems. Recent reports suggest that the all-ceramic crowns have excellent physical properties, wear resistance, and color stability. In addition, numerous ceramics have excellent biocompatibility, a natural appearance, and improved physical bonding with resin composite luting agents. However, the brittle nature of ceramics has been a major factor in their restriction for universal usage. Functional occlusal loading can generate stress in the luting agent, and the stress distribution may be affected by the marginal geometry at the finish line. Tooth preparation for fixed prosthodontics requires a decision regarding the marginal configuration. The design dictates the shape and bulk of the all ceramic crowns and influences the fit at the margin. Purpose: The purpose of this study was to evaluate the stress distribution within marginal configurations of all- ceramic crowns (90-degree shoulder, 110-degree shoulder, 135-degree shoulder). Material and methods: The force is applied from a direction of 45 degrees to the vertical tooth axis. Three-dimensional finite element analysis was selected to determine stress levels and distributions. Results and conclusion: The result of stress level for the shoulder marginal configuration was more effective on stress distribution at 135-degree shoulder margin. But the stresses concentrated around at 135-degree shoulder margin. The stress decreased apically at the surface between cements and alumina core, and increased apically at the surface between alumina core and veneering porcelain.

• Journal of the korean academy of Pediatric Dentistry
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• v.29 no.4
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• pp.632-640
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• 2002

The objective of the study was to apply the vibration technique to reduce the viscosity of bonding adhesives and thereby compare the bond strength and resin penetration into dentinal tubules achieved with those gained using the conventional technique. Eighty-eight noncarious extracted human permanent molar teeth were sectioned to remove the coronal enamel and were embedded in 1-inch PVC pipe with acrylic resin. The occlusal surfaces were placed so that the tooth and the embedding medium were at the same level to form one flat surface, and the samples were subsequently polished with silicon carbide abrasive papers. The samples were randomly assigned to 4 groups(n=22). On Group 1 and 2, Single Bond(3M-ESPE, St. Paul, USA) was used, and on Group 3 and 4, One-Step(Bisco Inc., Schaumburg, USA) was used, and each was applied according to its manufacturer's instructions. For Group 2 and Group 4, vibration was applied with ultrasonic scaler for 10 seconds, and the adhesive was light-cured for 10 seconds. Resin composite was condensed on to the prepared surface in two increments using a mold kit(Ultradent Products Inc., USA) and each was light-cured for 40 seconds. After 24 hours in tap water at room temperature the specimens were thermocycled, and shear bond strengths were measured with a universal testing machine(Instron 4465, Canton, USA). To investigate infiltration patterns of the adhesive materials, the surface of specimen was examined with scanning electron microscope. The results were as follows. 1. The shear bond strengths of vibration groups(Group 2, Group 4) were significantly greater than those of the non-vibration groups(Group 1, Group 3)(p<0.05). 2. The shear bond strengths of Single Bond and One-Step were not significantly different (p>0.05). 3. The vibration groups showed greater number of resin tags in tubules and lateral branches under SEM.

• Journal of the korean academy of Pediatric Dentistry
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• v.28 no.3
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• pp.464-470
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• 2001

The purpose of this study was to evaluate the tensile strength of light-cured restorative posterior resin-based composites. Five commercially available light-cured composites(Denfil : DF, P60 : PS, Unifil S : US, Z100 : ZH, Z250 : ZT) were used. Rectangular tension test specimens were fabricated in a teflon mold giving 5mm in gauge length and 2mm in thickness. Specimens were subjected to the 5,000 thermal cycles between $5^{\circ}C$ and $55^{\circ}C$ and the immersion time in each bath was 15 second per cycle. Tensile testing was carried out with Instron at a crosshead speed of 0.5mm/min and fractured surface were observed with scanning electron microscope. The obtained results were summarized as follows; 1. The tensile strength of PS was highest. PS was significantly higher than DF, US and ZH(p<0.05) but in the case of ZT was similar to PS(p>0.05). 2. The tensile strength DF was lowest. DF was significantly lower than PS, US, ZH and ZT(p<0.05). 3. The tensile strength of US and ZH were significantly lower than PS and ZT(p<0.05). but were significantly higher than DF(p<0.05). The tensile strength of US and ZH were similar(p>0.05).