• Structural Engineering and Mechanics
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• v.80 no.6
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• pp.701-709
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• 2021

The paper aims at improving the understanding and mitigating the effects of tunnel fires that may breakout due to the burning fuel and/or explosion within the tunnel. This study particularly focuses on the behavior of the commonly used horse shoe geometry of tunnel systems. The problem has been obtained using an adequate well-established program incorporating the Lagrangian approach. A transient-thermo-coupled static structural analysis is carried out. The effects of radiation and convection to the outer walls of the tunnel is studied. The paper also presents the impact of the hazard on the structural integrity of the tunnel. A methodology is proposed to study the tunnel fire using a model which uses equivalent steel sheet to represent the presence of reinforcements to improve the computational efficiency with adequate validation. A parametric study has been carried out and the effect of suitable lining property for mitigating the fire hazard is arrived at. Detailed analysis is done for the threshold limits of the properties of the lining material to check if it is acceptable in all aspects for the integrity of the tunnel. The study may prove useful for developing insights for ensuring tunnel fire safety. To conduct such studies experimentally are tremendously costly but are required to gain confidence. But, scaled models, as well as loading and testing conditions, cannot be studied by many trials experimentally as the cost will shoot up sharply. In this context, the results obtained from such computational studies with a feasible variation of various combinations of parameters may act as a set of guidelines to freeze the adequate combination of various parameters to conduct one or two costly experiments for confidence building.

• Journal of Environmental Science International
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• v.21 no.12
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• pp.1435-1447
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• 2012

The present study was conducted to determine the effect of hexaconazole (HEX), a triazole fungicide, on the growth, yield, photosynthetic response and antioxidant potential in cucumber (Cucumis sativus L.) plants subjected to UV-B stress. UV-B radiation and HEX were applied separately or in combination to cucumber seedlings. The growth parameters were significantly reduced under UV-B treatment, however, this growth inhibition was less in HEX treated plants. HEX caused noticeable changes in plant morphology such as reduced shoot length and leaf area, and increased leaf thickness. HEX was quite persistent in inhibiting shoot growth by causing a reduction in shoot fresh and dry weight. HEX noticeably recovered the UV-B induced inhibition of biomass production. Significant accumutation in anthocyanin and flavonoid pigments in the leaves occurred as a result of HEX or UV-B treatments. HEX permitted the survival of more green leaf tissue preventing chlorophyll content reduction and higher quantum yield for photosystemII under UV-B exposure. HEX treatment induced a transient rise in ABA levels in the leaves, and combined application of HEX and UV-B showed a significant enhancement of ABA content which activates $H_2O_2$ generation. UV-B exposure induced accumulation of $H_2O_2$ in the leaves, while HEX prevented UV-B induced increase in $H_2O_2$, indicating that HEX serves as an antioxidant agent able to scavenge $H_2O$ to protect cells from oxidative damage. An increase in the ascorbic acid was observed in the HEX treated cucumber leaves affecting many enzyme activities by removing $H_2O_2$ during photosynthetic processes. The activities of antioxidant enzymes including catalase(CAT), ascorbate peroxidase(APX), superoxide dismutase(SOD) and peroxidase(POD) in the leaves in the presence of HEX under UV-B stress were higher than those under UV-B stress alone. These findings suggest that HEX may participate in the enhanced tolerance to oxidative stress. From these results it can be concluded that HEX moderately ameliolate the effect of UV-B stress in cucumber by improving the components of antioxidant defense system.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.2
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• pp.78-85
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• 2010

A dynamic model has been developed to investigate the operability of a single and double-effect solar energy assisted parallel type absorption chiller. In the study, main components and fluid transport mechanism were modeled. And solar radiation and the solar collector were also modeled along with its control design. The model was run for the single mode with solar energy supply only and the solar/gas driving double effect mode. From the simulation results, it was found that the present configuration of the chiller is not capable of regulating solution flow rates according to variable solar energy input. And the issues of the excessive circulation flow rate and the mismatch between available solar power and cooling load discourages the use of the single mode, but the dual use of gas and solar power is recommendable in view of controllability and enhanced COP.

• Molecules and Cells
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• v.21 no.3
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• pp.367-375
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• 2006

We previously identified a novel cancer/testis antigen gene CAGE by screening cDNA expression libraries of human testis and gastric cancer cell lines with sera of gastric cancer patients. CAGE is expressed in many cancers and cancer cell lines, but not in normal tissues apart from the testis. In the present study, we investigated its role in the motility of cells of two human cancer cell lines: HeLa and the human hepatic cancer cell line, SNU387. Induction of CAGE by tetracycline or transient transfection enhanced the migration and invasiveness of HeLa cells, but not the adhesiveness of either cell line. Overexpression of CAGE led to activation of ERK and p38 MAPK but not Akt, and inhibition of ERK by PD98059 or p38 MAPK by SB203580 counteracted the CAGE-promoted increase in motility in both cell lines. Overexpression of CAGE also resulted in a reduction of ROS and an increase of ROS scavenging, associated with induction of catalase activity. Inhibition of ERK and p38 MAPK increased ROS levels in cells transfected with CAGE, suggesting that ROS reduce the motility of both cell lines. Inhibition of ERK and p38 MAPK reduced the induction of catalase activity resulting from overexpression of CAGE, and inhibition of catalase reduced CAGE-promoted motility. We conclude that CAGE enhances the motility of cancer cells by activating ERK and p38 MAPK, inducing catalase activity, and reducing ROS levels.

• Radiation Oncology Journal
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• v.11 no.1
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• pp.97-102
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• 1993

A retrospective analysis of various characteristics in 32 limited stage small cell lung cancer patients treated at the Department of Therapeutic Radiology in Kangnam St. Mary's Hospital, Catholic University Medical College from April 1983 to September 1991, was carried out to identify factors which had prognostic significance for survival from initiation of radiation therapy. There were 26 men and 6 women. Median age was 63 years (range: 24-78 years). The follow up duration was 1.5 to 44 months (median: 9 months). External radiation therapy was done with daily 160-180 cGy,5 fraction/week, total of 1000-6660 cGy (median: 4500 cGy) to the mediastinum by 6 MV linear accelerator. Of 32 Patients, 27 ($84.4{\%}$) patients were treated with combined modality (chemotherapy plus radiation therapy), and 5 ($15.6{\%}$) patients were treated with radiation therapy only. Complete responders were 12 patients ($37.5{\%}$), partial responders were 11 ($34.4{\%}$), and no responders were 9($28.1{\%}$). Karnofsky performance status over 70 (p<0.04), chemotherapy regimen (CAV, PV, and CAV+PV) (p<0.04),6 or more cycles of chemotherapy (p<0.007), radiation therapy over 4500 cGy (p<0.03), and radiation therapy responder (CR+PR) (p<0.003) showed a significantly favorable influence on 1 year survival rate. Age (p=0.545), sex (p=0.666), presence of superior vena cava syndrome (p=0.719), prophylactic cranial irradiation (p=0.217), and radiation therapy duration (p=0.491) had no effect on survival. Radiation induced side effects were transient esophagitis in 11 ($34{\%}$), general weakness in 9($28{\%}$), gastrointestinal symptoms in terms of nausea, vomiting and indigestion in 5 ($15{\%}$) and leukopenia in 1 ($3{\%}$).

• Transactions of the Korean Society of Mechanical Engineers B
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• v.27 no.10
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• pp.1377-1384
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• 2003

An analysis has been performed for active thermal control of the KOMPSAT monopropellant rocket engine assembly, i.e., dual thruster module(DTM). The main efforts of this work have been directed at determining proper heater sizes for propellant valves and catalyst beds necessary to maintain their temperatures within specified temperature ranges under KOMPSAT environment and operational conditions. The TAS incorporated with TRASYS thermal radiation analyzer was used to establish a complete heat transfer model which allows to predict the DTM temperature as a function of time. The thermal analysis has been performed in transient mode to verify the appropriate power for catalyst bed heaters necessary to increase catalyst bed temperature to the required value within a specified period of time. Similar analysis has been executed to validate the heater power for the thermostatically controlled primary and redundant heater circuits used to prevent hydrazine freezing, i.e., single fault. Moreover the effect of the radiative property of thermal control coating of heat shield was examined. Thruster firing condition was also simulated for the heat soakback condition. As a consequence, all thermal analysis results for DTM satisfactorily met the thermal requirements for the KOMPSAT DTM under the worst case average voltage, i.e. 25 volt.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.11 no.3
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• pp.437-444
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• 2000

In this paper, we propose a method that directly converts 3D CAD files for handheld phones designed by a commercial CAD S/W, PATRAN, to FDTD modeling with 1mm resolution. To qualify the accuracy of this method, we compared the calculation of radiation pattern using 3D transient far zone transformation with the measured results by gain comparison method in anechoic chamber and the difference is less than 0.5 dB. The calculation of magnetic field distributions on the front of handheld phones has been done to find a factor contributes to SAR. The result showed up the H-field in the width direction of the phone gives more dominant effect than the field in the length or inside to the front direction.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.17 no.7
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• pp.1558-1563
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• 2013

In this paper, we analyze the radio propagation path loss characteristics for the vertical electric dipole radiation over the perfect electric conductor(PEC) ground plane. Most research have been performed about the electromagnetic analysis of vertical electric dipole in free space for time domain or frequency domain. But this paper present the radio propagation path loss over PEC ground plane in time domain under the assumption of the vertical electric dipole as a base station. From the simulated results, the ground plane effect can change the location of near field from transmitting antenna and the transient responses at mobile are calculated. The results of this paper can be applied to surface radar or signal processing applications.

• Radiation Oncology Journal
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• v.12 no.2
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• pp.191-199
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• 1994

Purpose : This study was undertaken to show the clinical results of combined radiotherapy and hyperthermia in primary hepatoma Materials and Methods : Between December 1989 and March 1993, 50 patients with hepatomas were treated by combined radiotherapy and hyperthermia. Among them, we analyzed retrospectively 33 patients who received the complete course of treatment. The ages of the patients ranged from 36 to 75(mean age: 55.5 years). Twenty-six patients ($78.8\%$) were men, and 7 ($21.2\%$ were women. According to Child's classification, nine patients ($27.3{\%}$) were A group, 9 ($27.3\%$) were B group, 15 ($45.4\%$) were C group. Radiation therapy was done by a 6 MV and 15 MV linear accelerator. Patients were treated with daily fractions of 150-180 cCy to doses of 2550 cGy -4950 cGy (median : 3000 cGy). Local hyperthermia was done by 8 MHZ RF capacitive heating device (Cancermia. Green Cross Co., Korea), 50-60 min/session, 1-2 sessions/wk, and 8.5 sessions (median number)/patient. We analyzed the prognostic factors including age, sex, tumor type, Child's classification, $\alpha$-fetoprotein, liver cirrhosis, ascites, portal vein invasion, esophageal varix, number of hyperthermia, chemotherapy, total bilirubin level, Karnofsky perfomance status. Results : The overall 1-year survival was $24.2\%$, with a mean survival of 10months. Of 33 patients, tumor regression (PR+MR) was seen in $30.4\%$, no response was seen in $52.2\%,\;17.4\%$ patient was progressed. In patients who had tumor regression, the overall 1-year survival was $42.1\%$ with a mean survival of 14 months. Factors influencing the survival were sex (p=0.05), tumor type (p=0.0248), Child's classification (p=0.0001), liver cirrhosis (p=0.0108), ascites (p=0.0009), and Karnofsky perfomance status (p=0.0028). Complications developed in 28 patients, including 18 hot pain,5 fat necrosis, 3 transient fever, 2 nausea and vomiting. Conclusion : In this study, the results suggests that combined radiotherauy and hyperthermia may improve the survival rate of hepatoma.

• Applied Science and Convergence Technology
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• v.24 no.5
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• pp.136-141
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• 2015

We studied the compact anode design to develop 100 kW rotating anode X-ray tube with large focal spot 1.2 mm, small focal spot 0.6 mm and tube voltage 150 kV for large hospital digital radiography using computer thermal simulation. The larger thermal radiation effect in a high vacuum can reduce the temperature of anode so the method to increase the surface area of anode is investigated. The anode has the multi-tier shape at the back side of TZM body of anode and also bigger diameter of anode. The number of multi-tiers was varied from 6 to 15 and the diameter of anode was also varied from ${\Phi}74$ to ${\Phi}82$. From ANSYS transient thermal simulation result, we could obtain $1056.4^{\circ}C$ anode maximum temperature when applying 100 kW input power at 0.1 second on target focal track which is less than $1091^{\circ}C$ of the conventional 75 kW X-ray tube with reduced anode weight by 15.5% than the conventional anode. The compact anode of reduced anode weight is able to improve the unwanted noise when the rotor is rotating at high-speed and also reduce the rotational torque which the cost effective stator-coil is possible. It is believed that the anode with 15 ea multi-tiers using ${\Phi}82$ can satisfy with the specification of the anode heat capacity. From the results of this paper, it has been confirmed that the proposed compact anode can be used as the anode of 100 kW rotating anode X-ray tube for digital radiography.