• Archives of design research
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• v.17 no.4
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• pp.241-250
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• 2004

In this research, the copper alloy plates C2200, C5210, C7701, C8113 were selected to make datum and to identify further usage of metal craft experimentation. For its experimentation, the general welding and TIG welding methods were researched; for 2nd experimentation, the Reticulation and Electroforming skill's differences in color and temperature were researched. With these methods 3 different kinds of works are introduced for sample studies. For this research, Dr. Lee, Dong-Woo who works in Poongsan Metal Co, supported 4 kinds of copper alloy metals. Which are Commercial bronze (Cu-Zn), Deoxidiged Copper(Cu-Sn-P), Nickel Silver (Cu-Ni-Zn), and White Bronze (Cu-Ni); they were applied partly and wholly by the method of Laminatin, Reticulation, Fusing, and Electroforming skills. In case of C2200, the brass, the A. C. TIG welding method is better under 2mm slight plate; the D.C. TIG welding is better upper 2mm plate; and 250~300$^{\circ}C$ is recommended for remain heat treatment. In case of C5210, not having Hydrogen in high temperature return period, doesn't need Oxygen in high temperature and hardening in comparative high temperature neither, it is good for welding. It contains Sn 2-9% ad P 0.03-0.4% generally; and in accordance with the growth rate of Sn contain amount, the harden temperature boundary become broad. In case of cold moment after welding, they are recommended that higher speed TIG welding, smaller melting site and less than 200$^{\circ}C$ for pre-heating temperature. In case of C7701, the 10-20% Ni, 15-30% Zn are widely used.. If it is upper 30% Zn, it become (${\alpha}+{\beta}$) system and adhesive power rate become lower, and the productivity become lower in low temperature but the productivity become higher in high temperature. Nickel Silver's resistance of electricity is well; and the heatproof and incorrodibility is good, too. Lastly, in case of C8113, good at persistence in salty and grind; high in strength of high temperature. In case of white brass, contain 10-30% Nickel and hardened in high temperature and become single phrase. For these reason, the crystallization particles easily become large, if the resistance become higher small amount of Pb, P, S separation rate become higher.

• Korean Journal of Poultry Science
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• v.41 no.4
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• pp.297-303
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• 2014

Heat manipulation at early age has been known to help chickens cope with heat stress later in life. The present study was conducted to determine the effects of early heat conditioning at 5 days of age on performance in broilers when re-exposed to heat stress later in life. Day-old, 256 Arbor Acre boiler chicks were housed in two identical rooms where all broilers were exposed to a 23-h light: 1-h dark cycle throughout the study and provided with feed and water ad libitum. At the age of 5 days, one group was exposed to $37^{\circ}C$ for 24 hours and then returned to the temperature at which control birds were maintained (early heat condition group) while the other was maintained without heat modulation (Control). On 21 days, broilers were regrouped into 4 groups (CON+CON: control+control; CON+HS: control+heat stress; HC+CON: heat conditioning+control; HC+HS: heat conditioning+heat stress), and given 7 days for adaptation. On 28 days, birds in one room were exposed to heat stress ($21^{\circ}C{\rightarrow}31^{\circ}C$) for 3 days whereas those in the other were at room temperature. Heat stress resulted in decreased feed intake, water intake, and body weight gain (P<0.05), but increased rectal temperature and mortality (P<0.05). No beneficial effects of heat conditioning were detected when broilers were exposed to heat stress again at later in life. The present results were discussed together with other studies regarding possible differences in methods such as ages of breeders and strains, which may have resulted in the failure of heat conditioning to help broilers resist heat stress.

• Journal of Dental Rehabilitation and Applied Science
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• v.24 no.3
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• pp.269-281
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• 2008

Fatigue or overload can result in mechanical problems of implant components. The mechanical strength in the implant system is dependent on several factors, such as screw and fixture diameters, material, and design of the fixture-abutment connection and abutment. In these factors, the last rules the strength and stability of the fixture-abutment assembly. There have been some previous reports on the mechanical strength of the fixture-abutment assembly with the compressive bending test or short-term cyclic loading test. However, it is restrictive to predict the long-term stability of the implant system with them. The purpose of this study was to evaluate the influence of the design of the fixture-abutment connection and abutment on the mechanical strength and failure mode by conducting the endurance limit test as well as the compressive bending strength test. Tests were performed according to a specified test(ISO/FDIS 14801) in 4 fixture-abutment assemblies of the Osstem implant system: an external butt joint with Cemented abutment (group BJT), an external butt joint with Safe abutment (group BJS), an internal conical joint with Solid abutment (group CJO), and an internal conical joint with ComOcta abutment (group CJT). The following conclusions were drawn within the limitation of this study. Compressive bending strengths were decreased in order of group BJS(1392.0N), group CJO(1261.8N), group BJT(1153.2N), and group CJT(1110.2N). There were no significant differences in compressive bending strengths between group BJT and group CJT(P>.05). Endurance limits were decreased in order of group CJO(600N), group CJT(453N), group BJS(360N), and group BJT(300N). 3. Compressive bending strengths were influenced by the connection and abutment design of the implant system, however endurance limits were affected more considerably by the connection design.

• Clinical and Experimental Pediatrics
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• v.53 no.2
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• pp.195-202
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• 2010

Purpose : Despite recent advances in pulmonary hypertension management and surgery, appropriate guidelines remain to be developed for operability in congenital heart disease with pulmonary artery hypertension (PAH). Our aim was to evaluate clinical outcomes of patients with severe PAH who underwent surgical closure of left-to-right shunt lesions (LRSL) on the basis of pulmonary reactivity. Methods : We retrospectively reviewed 21 patients who underwent surgical closure of LRSL with severe PAH (${\geq}8$ Wood unit) from January 1995 to April 2009. The median age at operation was 26 years. Atrial septal defect, ventricular septal defect (VSD), VSD and patent ductus arteriosus (PDA), and PDA was present in 11, 4, 4, and 2 patients, respectively. Results : Operability was based on vasoreactivity of PAH. Of the 21 patients, 5 showed response to pulmonary vasodilator therapy and 8 showed vasoreactivity after balloon occlusion of defects. The remaining 8 patients were considered operable because of significant left-to-right shunt (Qp/Qs ${\geq}1.5$). Five patients underwent total closure of defects and 16 were left with small residual shunts. The median follow-up duration was 32 months. There was no significant postoperative mortality or morbidity. Systolic pulmonary artery pressure (PAP) decreased in all but 2 patients. All patients except 1 showed improvement of New York Heart Association functional class. Conclusion : Closure of LRSL in patients with severe PAH on the basis of pulmonary vasoreactivity seems reasonable. PAP and clinical symptoms improved in most patients. Further research is needed for the evaluation of long-term results.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.14 no.11
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• pp.5915-5922
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• 2013

In this study, with the aim of improving the performance of shale to allow for its use as coarse aggregate for concrete, we coated shale aggregates with water repellents and polymers and evaluated their physical properties such as density, water absorption rate, wear rate, and stability depending on the coating method. In addition, the effects of the performance improvement were evaluated by assessing the properties of fresh concrete produced by varying the shale substitution ratio, as well as the compressive strength, flexural strength, and freeze-thaw resistance according to curing ages. The test results revealed that the absolute dry densities of all coated aggregates satisfied the standard density for coarse aggregates for concrete(>$2.50g/cm^3$),and the absorption rate of the shale aggregate coated with water repellent decreased by about 50% compared with that of uncoated shale. The wear rate of the polymer-coated shale decreased by up to 13.0% compared with that of uncoated shale. All coated aggregates satisfied the stability standard for coarse aggregates for concrete(${\leq}12$). The water repellent-induced performance improvement decreased the shale aggregates' slump by about 20~30mm compared with that of the uncoated shale aggregates, and the air content of the repellent-coated shale aggregate increased by up to 0.9% compared with that of the uncoated shale aggregate. The compressive strength of the polymer-coated shale aggregates at a curing age of 28 days was RS(F) 95.7% and BS(F) 90.0%, and the flexural strength was RS(F) 98.0 % and BS(F) 92.0% of the corresponding values of concretes produced using plain aggregates. Furthermore, the concrete using polymer-coated shale aggregates showed a dynamic modulus of elasticity of RS(F) 91% and BS(F) 88% after 300 freeze-thaw cycles, thus demonstrating improved freeze-thaw durability.

• Korean Journal of Cognitive Science
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• v.15 no.4
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• pp.31-47
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• 2004

This study was carried out to examine the development of physical knowledge in children. Eighty children aged 3- to 11-year-old and 16 adults were participated in this study. Participants' knowledge about failing, sliding and sinking/floating objects was investigated to understand what kind of knowledge they had, whether their knowledge was organized as theory and what was the nature of the developmental change in physical knowledge. Results showed that, for falling object task children of all age had correct knowledge about object's falling phenomena. However, there were age differences in children's understanding of the cause of object's falling. As the children's age decreased, the frequency of explanation referring to the absence of supper rather than the gravity as the cause of falling phenomena increased. For the sliding object task, children of all age could predict the motion of sliding object correctly. But only a few 9- and 11-year-old children could understand the effect of object weight and relations between gravity, frictional force and their interactions. Children under age 7 showed no evidence of possessing these knowledge. For sinking or floating object task, children of all age and even adults showed difficulties in understanding the sinking or float phenomena per se. For the cause of these phenomena although a few 9- and 11-year-old children referred to buoyancy as the cause, they had no correct knowledge about the buoyancy. This was also true for the adults. As a conclusion, the results of this study suggested that, not 3, but as young as 5-year-old children's physical knowledge exited as a form of naive theory in terms of their use as a causal devise in explaining the cause of object motion. However, even the theory of 9- and 11-year-old children was lack of the abstractness and coherence, which were also important characteristics of a theory. Finally, developmental change in physical knowledge proceeded toward more frequent and consistent use of physical knowledge as causal device and more abstract and coherently organized theory.

• Journal of Korean Society of Environmental Engineers
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• v.36 no.11
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• pp.758-763
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• 2014

Soil microbial fuel cells (SMFC) have gained a great attention as an eco-friendly technology that can simultaneously generate electricity and treat organic pollutants from the contaminated soil. We evaluated the effect of electrode spacing and size on the performance of SMFC treating soil contaminated with organic pollutants. Maximum power density decreased with increase in electrode distance or decrease in electrode size, likely due to higher internal resistance. The maximum voltage and power density decreased from 326 mV and $19.5mW/m^2$ with 4 cm of electrode distance to 222 mV and $5.9mW/m^2$ with 9 cm of electrode distance. In case of electrode size test, the maximum voltage and power density generated was 291 mV, $0.34mW/m^3$ when both of anode and cathode area were $64cm^2$ with 4 cm of electrode distance. The maximum voltage decreased by 19~29% when the anode area decreased to $16cm^2$ while only 3~12% of voltage decreased with cathode area decrease. The maximum power density decreased by 49~68% with decreasing anode size, and by 29~47% with decreasing cathode size. These results showed that the anode area had more significant effects than the cathode area on the power generation of SMFC which has a high internal resistance due to a coexistence of soil and wastewater in the reactor.

• Pediatric Infection and Vaccine
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• v.5 no.1
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• pp.79-87
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• 1998

Purpose : The P1 protein of Mycoplasma pneumoniae mediates the attachment of the pathogen to its host cell and elicits a strong humoral immune response during infection with this organism. Mycoplasma pneumoniae strains can be classified into two groups(I and II) by PCR method of P1 cytadhesin gene. In this study, we evaluated the prevalence, epidemiological and clinical characteristics of each group. Methods : From 155 patients with Mycoplasma pneumoniae, who admitted to the Department of Pediatrics, Sung-Ae and Kwangmyung Sung-Ae Hospital between November 1996 and October 1997, we collected their throat swabs or nasopharyngeal aspirates for DNA extraction and serum for indirect hemagglutination test of Mycoplasma pneumoniae. The group specific PCR amplification were performed using specific oligonucleotide primers designed for P1 gene genotyping. Results : Group I(137 patients, 88.4%) occurred frequently than group II(18 patients, 11.6%). In both group, the most prevalent season was winter in 1996(Nov. to Dec.) and fall in 1997(Aug. to Oct.) The prevalent age was four to six years old. The number of male was more than female in both group; Group 1(1.2:1), Goup 2(1.6:1). No significant relationship were found between two groups in duration of fever and hospital days(P>0.05). The rate of high antibody titers(>1:5120) was lower in group I(6/137, 4.4%) than group II(2/18, 11.1%). Conclusion : Group I was much more prevalent than group II during 1996~1997 in Korea. There was no difference between two groups in epidemiological and clinical parameters except the rate of high antibody titers. Further follow-up survey will be needed for the epidemiologic and clinical studies of Mycoplasma pneumoniae in Korea.

• The Korean Journal of Nuclear Medicine Technology
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• v.15 no.1
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• pp.3-9
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• 2011

Purpose: Generally dual energy X-ray absorptiometry has been used for the purpose of evaluation of osteoporosis and treatment. Recently the interest of obesity came to be high and body percent fat test is increasing. Existing measure of body fat have to scan the whole body can be evaluated, but only lumbar spine and hip measurements was assumed to be whole body fat as well as improving the software. It tries to check whether the part measured value not being whole body measurement has the validity or not compared with the value calculated with the method that it is different, it forgives through a correlation with a (BIA) and (BMI). Materials and Methods: In 2010, the body percent fat was measured among the examinee coming to the Asan Medical Center public health care center from March till August against 90 females more than 40 years old through (DXA) and BIA. BMI utilized the value which wrote an hight and weight measured through the body measuring instrument in the examinee information and is automatically calculated. In addition, it classified as the low weight ($13-18.5kg/m^2$), normal ($18.5-25kg/m^2$), and corpulence ($25-30kg/m^2$) based on BMI and so that it could check whether there was the difference according to the weight or not BMI and BIA and correlation between DXA were analyzed in each group. The statistical program for the analysis used SPSS 12.0. Results: The comparison of DXA at 3 which it divides into the low weight and normal and corpulence groups and BIA did not show the difference noted statistically in all groups and the between group comparison was exposed to do not have a meaning. The body percent fat measured by the correlation analysis result DXA at the state that it doesn't divide into the group showed the high correlation (r=0.908, p0.01) noted statistically compared with BMI and showed the high correlation noted statistically in a comparison with BIA (r=0.927, p0.01). Conclusion: It confirmed that the whole body percent fat presumed from the part bone density measurement showed the excel correlation compared with BIA and BMI and information is high. There is still no clear standard about the presumed whole body percent fat and it is difficult to evaluate the fat evaluation by the bone mineral density measurement. However, it is determined that the information offering which is more objective through the comparative study with the body percent fat which is very efficient and in that it can obtain till the information about a fat as well as diagnosis of the osteoporosis through the bone density checkup is measured by the afterward telegraph bone density checkup and is clinically useful is possible.

• Korean Journal of Food Science and Technology
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• v.26 no.3
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• pp.213-220
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• 1994

Gastrodia (G) Rhizoma has been used clinically as an oriental herbal medicine with sedative, anticonvulsive, and depressor effects. The present study tested effects of G. Rhizoma extracts on the coronary circulation and myocardial oxygen consumption in perfused rat hearts. Sprague Dawley rats (SD) and spontaneously hypertensive rats (SHR) were employed as experimental animals and nonworking Langendorff heart perfusion technique introduced for heart experiments. G. Rhizoma extracts were prepared from grinding G. Rhizoma into powder, extracting in water and 50% ethanol for 4 or 16 hr and diluting with Krebs-Henseleit bicarbonate perfusion buffer to be 70%. Hearts were perfused with bicarbonate buffer oxygenated with 95% $O_{2}:$ 5% $CO_{2}$ at constant coronary perfusion pressure of $90cmH_{2}O$. The diluted extracts were infused into coronary arteries in a concentration of $1{\sim}5\;{\mu}M$ for $7{\sim}8 min. While in SD water- or ethanol-extracts of G. Rhizoma extracted for 16 hr increased coronary perfusate flow (CPF) and decreased coronary vascular resistance (CVR), ethanol-extracts in SHR produced coronary vasoconstriction associated with enhanced CVR. G. Rhizoma extracts-induced increase in CPF reduced myocardial oxygen extraction, and thus myocardial oxygen consumption ($MVO_{2}$) remained at that observed prior to infusion of extracts. In SD and SHR 16 hr-water-extracts markedly altered coronary venous effluent pH and $Pco_{2}$ and evoked metabolic acidosis, which could be a coronary vasodilator mechanism decreasing CVR. In this study, the extracts decreasing CVR in SD and SHR did not augment the lactate production. Therefore, although the effects of the extracts on cardiac function and coronary circulation depended on solvents and duration for extraction, the 16hr-water-extracts, at least, exhibited coronary vasodilation in SD and SHR. Conversely, ethanol-extracts constricted coronary arteries in SHR. G. Rhizoma extracts-induced vasodilation might be due to the metabolic acidosis rather than due to the increased lactate production. The results indicate that G. Rhizoma extracts obtained from proper extracting procedures can be used as a safe and clinically applicable herbal medicine in the cardiovascular diseases such as coronary artery disease and hypertension for vasodilatory and antihypertensive actions.