• Journal of the Korean Wood Science and Technology
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• v.38 no.1
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• pp.1-10
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• 2010

In this study, to study an effective use and improve strength performances of woods and wood-based materials, three-ply hybrid laminated woods which are composed of spruce in the face and three kinds of wood-based boards (MDF, PB, OSB) in the core were manufactured, and the effect of constitution elements used for the core laminae on bending creep performances was investigated. The shape of creep curves showed exponential function plots which the upper right side was increased, and differed among the kinds of wood-based boards used for the core laminae of hybrid laminated wood. The creep deformation perpendicular to the grain of faces of hybrid laminated woods was in order $C_{\perp}$(P) > $C_{\perp}$(M) > $C_{\perp}$(O) with PB, MDF and OSB in the core, respectively. It was found that the creep deformation arranged with OSB in the core had 2 times smaller than those arranged with MDF and PB in the core. By hybrid laminating, the creep deformation of spruce perpendicular to the grain was markedly decreased. On the other hand, the creep deformation parallel to the grain of the faces ($C_{\parallel}$ type) of hybrid laminated woods was in order $C_{\parallel}$(P) > $C_{\parallel}$(O) > $C_{\parallel}$(M) with PB, OSB and MDF in the core. The ratios among three hybrid laminated woods were considerably decreased, especially the difference between $C_{\parallel}$(P) and $C_{\parallel}$(O) hybrid laminated woods arranged with PB and OSB in the core was very small. These values showed 0.108~0.464 times smaller than creep deformation of three wood-based boards and it was found that creep deformation of three wood-based boards was considerably decreased by hybrid laminating. Creep anisotropy of hybrid laminated woods was greater in creep deformation than in initial deformation, whereas it was found that the values was much smaller than that of spruce parallel laminated woods.

• Tuberculosis and Respiratory Diseases
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• v.45 no.4
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• pp.746-753
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• 1998

Background : Cigarette smoking is closely related to both lung cancer and chronic obstructive pulmonary disease. The incidence of lung cancer is higher in patients with obstructive ventilatory impairment than in patients without obstructive ventilatory impairment regardless of smoking. So, obstructive ventilatory impairment is suspected as an independent risk factor of lung cancer. Methods: For the evaluation of the role of obstructive ventilatory impairment as a risk factor of lung cancer, a total of 73 cases comprising 47 cases of malignant and 26 benign solitary pulmonary nodule were analyzed retrospectively. A comparative study of analysis of forced expiratory volume curves and frequencies of obstructive ventilatory impairment were made between cases with malignant and benign nodules. Results: In comparison of vital capacity and parameters derived from forced expiratory volume curve between two groups. VC, FVC and $FEV_1$ were not significantly different. whereas $FEV_1/FVC%$ and FEF 25-75% showed a significant decrease in the cases with malignant nodule. The frequency of obstructive ventilatory impairment determined by pulmonary function test was significantly higher in the cases with malignant nodule(23.4%) than in benign nodule(3.8%). When the risk for lung cancer was examined by the presence or absence of obstructive ventilatory impairment using the logistic regression analysis, the unadjusted relative risk for the lung cancer of obstructive ventilatory impairment was 17.17. When the effect of smoking and age were considered, the relative risk was to 8.13. Conclusion: These findings suggest that an obstructive ventilatory impairment is a risk factor of lung cancer.

• Journal of the Society of Naval Architects of Korea
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• v.28 no.2
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• pp.52-68
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• 1991

A new propeller series is developed using the newly developed blade section(KH18 section) which behaves better cavitation characteristics and higher lift-drag ratio at wide range of angle-of-attack. The pitch and camber distributions are disigned in order to have the same radial and chordwise loading distribution with the selected circumferentially averaged wake input. Since the geometries of the series propeller, such as chord length, thickness, skew and rate distribations, are selected by regression of the recent full scale propeller geometric data, the performance prediction of a propeller at preliminary design stage can be mure realistic. Number of blades of the series propellers is 4 and the expanded blade area ratios are 0.3, 0.45, 0.6 and 0.75. Mean pitch ratios are selected as 0.5, 0.65, 0.8, 0.75 and 1.1 for each expanded area ratio. The new propeller series is composed of 20 propellers and is named as KD(KRISO-DAEWOO) propeller series. Propeller open water tests are performed at the experimental towing tank, and the cavitation observation tests and fluctuating pressure measurements are carried out at the cavitation tunnel of KRISO. $B_{P}-\delta$ curves, which can be used to select the optimum propeller diameter at the preliminary design stage, are derived from a regression analysis of the propeller often water test results. The KD-cavitation chart is derived from the cavitation observation test results by choosing the local maximum lift coefficient and the local cavitation number as parameters. The caviy extent of a propeller can be predicted more accurately by using the KD-cavitation chart at a preliminary design stage, since it is derived from the results of the cavitation observation tests in the selected ship's wake, whereas the existing cavitation charts, such as the Burrill's cavitation chart, are derived from the test results in uniform flow.

• Radiation Oncology Journal
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• v.11 no.1
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• pp.35-42
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• 1993

The dose response of the number of micronuclei in cytokinesis-blocked (CB) lymphocytes after in vitro irradiation with $\gamma$-rays and neutrons in the 5 dose ranges was studied for a heterogeneous population of 4 donors. One thousand binucleated cells were systematically scored for micronuclei. Measurements performed after irradiation showed a dose-dependent increase in micronuclei (MN) frequency in each of the donors studied. The dose-response curves were analyzed by a linear-quadratic model, frequencies per 1000 CB cells were ($0.31{\pm}0.049$)D+($0.0022{\pm}0.0002)D^2+(13.19{\pm}1.854) (r^2=1.000,\;X^2=0.7074,\;p=0.95$) following $\gamma$ irradiation, and ($0.99{\pm}0.528$)\;D+(0.0093{\pm}0.0047)\;D^2+(13.31{\pm}7.309)\;(r^2=0.996,\;X^2=7.6834,\;p=0.11) following neutrons irradiation (D is irradiation dose in cGy). The relative biological effectiveness (RBE) of neutrons compared with $\gamma$-rays was estimated by best fitting linear-quadratic model. In the micronuclei frequency between 0.05 and 0.8 per cell, the RBE of neutrons was $2.37{\pm}0.17$. Since the MN assay is simple and rapid, it may be a good tool for evaluating the $\gamma$-ray and neutron response.

• Journal of Korean Society of Environmental Engineers
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• v.29 no.9
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• pp.1013-1019
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• 2007

Electronic wastes have increased tremendously. However, any reliable treatment methodologies have rarely been established. Electronic wastes have posed serious disposal problem due to their physico-chemical stability. This paper investigated the application possibility of pyrolysis for the purpose of recycling the p-CCL(phenol based Copper Clad Laminate). Thermogravimetric analysis(TGA) was used to investigate the thermal decomposition pattern of p-CCL. We elucidated the characteristics of pyrolysis by-products at operating temperatures of 280, 350 and $600^{\circ}C$. GC/MS and FT-IR were used to characterize the liquid by-products along with general characterization methods such as Ultimate Analysis, Proximate Analysis and Heating Value, whereas general characterization methods were only introduced for the solid by-products. At a heating rate of $5^{\circ}C$/min, TGA curves exhibited three decomposition stages: (1) low-temperature decomposition region$(<280^{\circ}C)$, (2) medium temperature region$(280\sim350^{\circ}C)$ and (3) high-temperature region$(>350^{\circ}C)$. The major compounds of liquid by-products at low- and medium-temperatures were accounted for by water and phenol, whereas branched phenols and furans were major compounds at high-temperatures. As the temperature increases, volatile quantities decreased but the fixed carbon increased. High heating values of solid by-products($7,400\sim7,600$ kcal/kg) would suggest that the solid by-products could be applicable as fuel. In addition, high fixed carbon but low ash content of the solid by-products offered an implication that they are capable of being upgradable for adsorbent after applying appropriate activating process.

• Journal of the korean academy of Pediatric Dentistry
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• v.32 no.1
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• pp.89-100
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• 2005

The purpose of this study was to analyze the morphometrics of primary second molar and permanent first molar. Samples were consisted of normal occlusion in the primary dentition(50 males and 50 females) and permanent dentition(43 males and 43 females). Their upper and lower plaster casts were used and their measuring points were decided, through 3-dimensional laser scanning(3D Scanner, DS4060, LDI, U.S.A.), fitting standard horizontal plane were made for measuring the intercuspal distance, volume of intercuspal area and section curve. The results were as follows; 1. Average distance from the fit plane to the cusp tips of mandibular primary second molar was smaller than any other tooth. (0.05-0.09 mm in male and 0.04-0.09 mm in female). 2. Intercuspal distances of mandibular primary second molar and permanent first molar were larger in male than in female. Especially, there was statistical significance in primary second molar(p<0.05). 3. Intercuspal distance between distobuccal and distolingual cusp was larger in maxillary primary second molar, except cross intercuspal distances. And distances between distal and distolingual cusp, in mandibular primary second molar, between mesiolingual and mesiobuccal cusp, in maxillary first molar, and between distolingual and mesiolingual cusp, in mandibular first molar were larger than any other intercuspal distance. 4. Volume of intercuspal area of primary second molar and permanent first molar was larger in mandible than in maxilla and that of permanent first molar was 1.40-1.75 times of primary second molar (p<0.05). Also it was larger in male than in female, but there was no statistical significance. 5. In most cases, section curves were wider and deeper in permanent dentition than in primary dentition. Except cross intercuspal distances, in maxilla, section curve between mesiobuccal and mesiolingual cusp was the deepest in both dentition. In mandible, section curve between distobuccal and distal cusp was the deepest in permanent dentition and between distolingual and distal cusp was the deepest in primary dentition.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.6 no.1
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• pp.1-11
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• 1986

Welded connectors of the cover plates, the transverse stiffeners of the plate girders, and the gusset plates of the plates girders or box girders, were selected as studying objects. A simplified method of drawing the S-N curves in these welded joints by a computer program without the direct fatigue tests was established. The plots on the S-N curve using the values from the practical fatigue tests were compared with the results from the method of the computer programming. The results of these studies are as follows. It appeared that the fatigue life by calculation method was a little less than the practical fatigue life from the actual tests. The latter values included both life $N_c$ of occurrence of initial crack $a_i$ and the life $N_p$ of propagation of critical crack. On the other hand, the former values included only the life $N_p$. Therefore, these results should be considered as justifiable ones. Since the difference between the two results was not significant, the results by calculation method should be in the conservation side when the safety of the structures was considered. Consequently, the results by calculation method should be applicable to the fracture fatigue design of structure. For reference, the same fatigue tests were performed with the specimens of 3 pieces in each case made of the low-strength steel, SS 41. The results went unexpected showing that the fatigue strength was lower in the case of low-strength steel. That is, in the case of the cover plate, the fatigue strength became slowly higher than the case of high-strength steel, SWS 50. That was observed when the maximum testing stress was higher than $14kg/mm^2$. In addition, in the case of the transverse stiffener, the fatique strength became rapidly higher than the case of SWS 50. That was observed when the maximum testing stress was lower than $31kg/mm^2$. It was thought that more such fatigue tests should be performed for more reliable results.

• Journal of Life Science
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• v.23 no.8
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• pp.1025-1031
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• 2013

From a 95% ethanolic extract of H. diffusa, four marker compounds (HD1~HD4) were isolated, which were relatively unique and exist in comparably high contents. The structures of marker compounds were identified as digitolutein (1), 2-hydroxy-3-methylanthraquinone (2), (E/Z)-6-O-p-coumaroyl scandoside methyl ester (4:1 mixture) (3), and (E/Z)-6-O-p-methoxycinnamoyl scandoside methyl ester (4:1 mixture) (4), respectively, on the basis of $^{13}C$ and $^1H$-NMR analyses. The calibration curves of marker compounds showed high linearity, as their correlation coefficient ($R^2$) were in the range of 0.9991~0.9999. In addition, the limit of detection (LOD) and the limit of quantification (LOQ) were $0.03{\sim}0.07{\mu}g/ml$ and $0.099{\sim}0.231{\mu}g/ml$, respectively. The intra-day/inter-day precision and accuracy were 0.23~2.00%/0.25~1.16% and 94.60~108.44%/94.73-110.23%, respectively. The optimal HPLC conditions for the simultaneous quantification of HD1~HD4 were as follows: stationary phase; Merck Chromolith RP-18e ($100{\times}4.6mm$, $5{\mu}m$), column temp.; room temperature, UV detection at 280 nm, flow rate; 2.0 ml/min, injection volume; $10{\mu}l$, mobile phase; start with the mixture of 80% solvent A ($H_2O$ containing 0.5% acetic acid) and 20% solvent B (methanol containing 0.5% acetic acid) and gradually decrease solvent A to 40% in 9 min., then retain this condition to 18 min. Under the HPLC condition, the four marker compounds 1~4 were successfully separated without any interference of other constituents. The results obtained in this study are expected to be helpful for the development of nutraceutics and natural medicines and for the quality control of this plant.

• The Korean Journal of Nuclear Medicine
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• v.33 no.2
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• pp.131-142
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• 1999

Purpose: Either gated myocardial perfusion SPECT or attenuation corrected SPECT can be used to improve specificity in the diagnosis of coronary artery disease. We investigated in this study whether gating or attenuation correction improved diagnostic performance of rest/stress perfusion SPECT in patients having intermediate pre-test likelihood of coronary artery disease. Materials and Methods: Sixty-eight patients underwent rest attenuation-corrected T1-20l/dipyridamole stress gated attenuation-corrected Tc-99m -MIBI SPECT using an ADAC vertex camera (M:F=29:39, aged $59{\pm}12$ years, coronary artery stenosis ${\geq}70%$, one vessel: 13, two vessel: 18, three vessel: 8, normal: 29). Using a five-point scale, three physicians graded the post-test likelihood of coronary artery disease for each arterial territory (1:normal, 2: possibly normal, 3:equivocal, 4. possibly abnormal, 5: abnormal). Sensitivity, specificity and area under receiver-operating-characteristic curves were compared for each operator between three methods : (A) non-attenuation-corrected SPECT; (B) gated SPECT added to (A): and (C) attenuation-corrected SPECT added to (B). Results: When grade 3 was used as the criteria for coronary artery disease, no differences in sensitivity and specificity were found between the three methods for each operator. Areas under receiver-operating-characteristic curves for diagnosis of coronary artery disease revealed no differences between each modality (p>0.05). Conclusion: In patients at intermediate risk of coronary artery disease, gated SPECT and attenuation- corrected SPECT did not improve diagnostic performance.

• Tuberculosis and Respiratory Diseases
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• v.42 no.6
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• pp.846-854
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• 1995

Background: Cytokeratin 19 is a subunit of cytokeratin intermediate filament expressed in simple epithelia such as respiratory epithelial cells and their malignant counterparts. An immunoradiometric assay is available to detect a fragment of the cytokeratin, referred to as Cyfra 21-1 in the serum. This study was conducted to evaluate the clinical utility of this new marker in the diagnosis of lung cancer compared with established markers of squamous cell carcinoma antigen (SCC Ag) and carcino-embryonic antigen(CEA). In addition, we compared the diagnostic sensitivity and specificity of Cyfra 21-1 with those of SCC Ag in squamous cell carcinoma of the lung. We also measured the level of Cyfra 21-1 in the different stages of squamous cell carcinoma of the lung. Method: We measured Cyfra 21-1(ELSA-CYFRA 21-1), SCC Ag(ABBOTT SCC RIABEAD) and CEA(ELSA2-CEA) in 79 patients with primary lung cancer and in 78 persons as a comparison group including 32 patients with pulmonary tuberculosis, 23 patients with benign lung disease and 23 cases with healthy individual. Cyfra 21-1 is measured by a solid-phase immunoradiometric assay(CIS Bio International, France) based on the two-site sandwich method. SCC Ag is measured by a radioimmunoassay(Abbott Laboratories, USA). CEA is measured by a immunoradiometric assay(CIS Bio International, France). All data were expressed as the mean$\pm$standard deviation. Results: 1) The mean value of Cyfra 21-1 was $18.38{\pm}3.65\;ng/mL$ in the lung cancer and $1.l6{\pm}0.53\;ng/mL$ in the comparison group(p<0.0001). SCC Ag was $3.53{\pm}6.06\;ng/mL$ in the lung cancer and $1.19{\pm}0.5\;ng/mL$ in the comparison group(p<0.01). CEA was $35.03{\pm}13.9\;ng/mL$ in the lung cancer and $2.89{\pm}1.01\;ng/mL$ in the comparison group(p<0.0001). 2) Cyfra 21-1 level in squamous cell carcinoma($31.52{\pm}40.13\;ng/mL$) was higher than that in adenocarcinoma($2.41{\pm}1.34\;ng/mL$)(p<0.0001) and small cell carcinoma($2.15{\pm}2.05\;ng/mL$)(p=0.007). SCC Ag level in squamous cell carcinoma($5.1{\pm}7.68\;ng/mL$) was higher than that in adenocarcinoma($1.36{\pm}0.69\;ng/mL$)(p=0.009) and small cell carcinoma($1.1{\pm}0.24\;ng/mL$) (p=0.024). 3) The level of Cyfra 21-1 was not correlated with the progression of stage in squamous cell carcinoma of the lung. 4) Using the cut-off value of 3.3ng/mL, the diagnostic sensitivity of Cyfra 21-1 was 83% in squamous cell carcinoma, 22% in adenocarcinoma and 17% in small cell carcinoma. The sensitivity of SCC Ag and CEA were 39% and 20%, respectively in squamous cell carcinoma, 11% and 39% in adenocarcinoma, and 0% and 33% in small cell carcinoma. 5) Comparison of the receiver operating characteristics curves(ROC curve) for Cyfra 21-1, SCC Ag and CEA revealed that Cyfra 21-1 showed highest diagnostic sensitivity among them in the diagnosis of lung cancer. Conclusion: Cyfra 21-1 is thought to be a better tumor marker for the diagnosis of lung cancer than SCC Ag and CEA, especially in squamous cell carcinoma of the lung.