• Progress in Medical Physics
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• v.29 no.4
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• pp.123-136
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• 2018

The complex dose distribution and dose transfer characteristics of intensity-modulated radiotherapy increase the importance of precise beam data measurement and review in the acceptance inspection and preparation stages. In this study, we propose a process map for the introduction and installation of high-precision radiotherapy devices and present items and guidelines for risk management at the acceptance test procedure (ATP) and commissioning stages. Based on the ATP of the Varian and Elekta linear accelerators, the ATP items were checked step by step and compared with the quality assurance (QA) test items of the AAPM TG-142 described for the medical accelerator QA. Based on the commissioning procedure, dose quality control protocol, and mechanical quality control protocol presented at international conferences, step-by-step check items and commissioning guidelines were derived. The risk management items at each stage were (1) 21 ionization chamber performance test items and 9 electrometer, cable, and connector inspection items related to the dosimetry system; (2) 34 mechanical and dose-checking items during ATP, 22 multileaf collimator (MLC) items, and 36 imaging system items; and (3) 28 items in the measurement preparation stage and 32 items in the measurement stage after commissioning. Because the items presented in these guidelines are limited in terms of special treatment, items and practitioners can be modified to reflect the clinical needs of the institution. During the system installation, it is recommended that at least two clinically qualified medical physicists (CQMP) perform a double check in compliance with the two-person rule. We expect that this result will be useful as a radiation safety management tool that can prevent radiation accidents at each stage during the introduction of radiotherapy and the system installation process.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.22 no.2
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• pp.43-50
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• 2022

In this paper, we designed and verified a Far-field measurement system for measuring the performance of an antenna operating in millimeter wave(W-band). For the antenna test, a measurement system should be selected according to the type of antenna, measurement items, measurement environment and period, etc. In the case of near-field measurement, it takes a lot of time because the number of measurement items increases when the antenna has multiple channels or various beams. Such an antenna can reduce the measurement time through Far-field measurement, and only necessary measurement items can be measured. Therefore, this study secured precise alignment of the far-field measurement system using a high-power laser and improved the measurement accuracy by applying a double amplifier system. The designed system was built in the anechoic chamber and verified by comparison with the verified Near-field measurement system.

• Korean Journal of Exercise Nutrition
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• v.13 no.1
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• pp.75-81
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• 2009

This study aims to find out the effect of ingestion of 3 mg·kg^-1 caffeine on fluid-electrolyte balance and Tty change during exercise under heat environment of 30~32℃ (40-50% humidity). Five trained males who routinely trained for approximately 60 min·d^-1, 3-6 d·wk^-1 (age; 28.20±3.56yrs, height; 174.56±5.46 cm, body mass; 76.13±9.02 kg, body fat(%); 14.24±3.99, VO₂max; 54.00±4.30 mL·kg^-1·min^-1, exercise career; 4.20±1.95yrs) performed 40min of treadmill running in heat chamber. The study was a double-blind, randomized, crossover design. Body mass change following exercise was higher for the PLAC (Placebo) and CAFF (Caffeine) in comparison to the CON (Control), there was no significant difference between the CAFF, PLAC, CON (p= .997). The U_sg not significant differences (p= .731) and Osm_urine not significant differences between the CAFF, PLAC, CON (p= .901). There also were not significant between the CAFF, PLAC, CON for [Na⁺]_urine and [K⁺]_urine (p= .928, p= .469). In the case of Tty, although the increase rate of Tty was the highest for the CAFF on exercise early, exercise the second half in comparison to the CON and PLAC, there was not significant interaction effect between the CAFF, PLAC, and CON of Tty (p= .067), In conclusion, it was confirmed that the 3 mg·kg^-1 caffeine ingestion prior to exercising in heat environment does not impart negative effect on body fluid, electrolyte balance and changes in Tty.

• New Physics: Sae Mulli
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• v.69 no.10
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• pp.1107-1114
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• 2019

Producing extremely stable high temperature and pressure condition is crucial in order to synthesize novel materials with various functions and to investigate their static and dynamic properties. Already a high pressure in the Mbar range, which is necessary to make novel materials, can be acquired by using a Diamond Anvil Cell (DAC), In this study, a laser-heating system combined with the DAC was designed and installed using two 1064-nm, 100-W fiber lasers on different sides of the DAC to heat the sample and three spectrometers to measure the temperature, pressure, and Raman spectra. A stainless-steel gasket, which is generally used as a sample chamber in high-pressure experiments, was heated to make a thermal radiation source, and the temperature of the heated gasket was obtained by measuring the spectrum of the radiation. By applying this technique, we were able to make various materials and to investigate their physical properties under extreme conditions.

• Korean Journal of Heritage: History & Science
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• v.53 no.2
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• pp.242-253
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• 2020

Six ornamental metal quiver fittings were excavated from stone chamber No.1 of the ancient tombs of Jeongchon, Bokam-ri, Naju. The ornamental quiver fittings are metal, but the body of the quiver was made of organic material, so that it corroded and disappeared in the burial environment. The ornamental metal quiver fittings were made in pairs, and decorated one quiver according to the location they were found in and their forms. The ornamental metal quiver fitting can be divided into two types: A band style ornament (帶輪狀金具) which decorates the arrow pouch, and a board style ornament (板狀金具) which decorates the board connecting the waist belt. Two ornamental metal quiver fittings excavated from wooden coffin 2 of stone chamber No.1, were made in the band style, while the ornamental metal quiver fittings from southeast of stone chamber No.1 were identified as two boardstyle ornaments and two band-style ornaments for what was presumed to be belt loops. Material analysis of the ornamental metal quiver fittings shows that they are made of a gilt bronze plate attached to an iron plate, and the surface is marked with a speck of chisel to make lines and patterns. Chemical composition analysis (XRF) established that 24~40wt% Au and 50~93wt% Cu were detected on the gold surface, and it was confirmed that bronze corrosion had taken place on the gilt surface. SEM-EDS analysis of the gold plating layer identified a working line for glossing, and 7~9wt% Hg and an amalgam of gilt layers was detected, confirming the amalgam gilding. CT and FT-IR analysis established that the band style was double-layered with silk fabric under the iron plate, and there was also a lacquer piece underneath. The band-style ornaments have two layers of silk under the iron plate, along with lacquer pieces. Adding the fabric to the arrow pouch increases adhesion and decorative value. It is assumed that the lacquer pieces indicate that the surface of the lacquered arrow pouch had fallen together with the ornaments. On the other hand, the board-style ornaments have a thick layer of organic matter under the iron plate, but this is difficult to identify and appears to be a remnant of the quiver board. The characteristics of these ornamental metal quiver fittings were similar in Baekje, Silla, and Gaya cultures from the late 4th to the late 5th centuries, and enable us to identify the art of ancient gold craftwork at that time.

• Radiation Oncology Journal
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• v.16 no.4
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• pp.497-504
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• 1998

Purpose : To evaluate the usefulness of electronic portal imaging device through objective compare of the images acquired using an EPID and a conventional port film Materials and Methods : From Apr. to Oct. 1997, a total of 150 sets of images from 20 patients who received radiation therapy in the pelvis area were evaluated in the Inha University Hospital and Severance Hospital. A dual image recording technique was devised to obtain both electronic portal images and port film images simultaneously with one treatment course. We did not perform double exposure five to ten images were acquired from each patient. All images were acquired from posteroanterior (PA) view except images from two patients. A dose rate of 100-300 Mu/min and a 10-MV X-ray beam were used and 2-10 MUs were required to produce a verification image during treatment. Kodak diagnostic film with metal/film imaging cassette which was located on the top of the EPID detector was used for the port film. The source to detector distance was 140 cm. Eight anatomical landmarks (pelvic brim, sacrum, acetabulum. iliopectineal line, symphysis, ischium, obturator foramen, sacroiliac joint) were assessed. Four radiation oncologist joined to evaluate each image. The individual landmarks in the port film or in the EPID were rated - very clear (1), clear (2), visible (3), not clear (4), not visible (5). Results : Using an video camera based EPID system. there was no difference of image quality between no enhanced EPID images and port film images. However, when we provided some change with window level for the portal image, the visibility of the sacrum and obturator foramen was improved in the portal images than in the port film images. All anatomical landmarks were more visible in the portal images than in the port film when we applied the CLAHE mode enhancement. The images acquired using an matrix ion chamber type EPID were also improved image qualify after window level adjustment. Conclusion : The quality of image acquired using an electronic portal imaging device was comparable to that of the port film. When we used the enhance mode or window level adjustment. the image quality of the EPID was superior to that of the port film. EPID may replace the port film.

• Journal of Chest Surgery
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• v.34 no.8
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• pp.597-603
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• 2001

Background: The purpose of writing this article is to get better clinical results and further clinical improvement based on subject to 110 cases of cardiac surgery which were performed and clinically analyzed. Material and Method: Since January 1995, the patent ductus arteriosus surgery had started in our hospital. In February 1999, an open heart surgery had started and up to September 2000, total of 110 cases were performed as of double ligation of patent ductus arteriosus(10 cases) and open heart surgery(100 cases). Result: Among the patients, Korean-Chines was 74(67.3%) and Han-Chinese was 35(31.8%). Congenital heart disease was 95 cases and acquired valvular heart disease was 15 cases. 83 cases of acyanotic congenital heart disease consisted of ventricular septal defect(VSD) with associated anomaly(45 cases), atrial septal defect(ASD) with associated anomaly(20 cases), patent ductus arteriosus(PDA) with associated anomaly(11 cases), cogenital aortic stenosis(5 cases), double chamber right ventrical(1 case) and Ebstein's anomaly(1 case). Among the 12 cases of cyanotic congenital heart disease, 11 cases of tetralogy of Fallot underwent total correction. Among the 15 cases of acquired valvular heart disease, valvular replacement(7 cases), double valve replacement (3 cases), mitral valve replacement(3 cases) and aortic valve replacement(1 case) were performed. And 8 cases of valvuloplasty were performed by using of commissurotomy, chordal plasty, plasty of papillary muscle, ring type annuloplasty, repair of leaflet. Conclusion: on cogenital heart disease, short term results of surgery for acyanotic cogenital heart disease was good. Among the cyanotic congenital heart disease, tetralogy of Fallot showed a little difference of recovery according to the surgery method so that further follow up observation was needed for long term result. On acquired valvular heart disease, especially, in terms of short term result of valvuloplasty, was relatively good, but further follow up observation was also needed for long term result. There wasn's any operative mortality.

• Journal of Chest Surgery
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• v.17 no.2
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• pp.223-230
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• 1984

Since January 1977 to the end of September 1982, total 60 Ionescu-Shiley pericardial xenograft heart valves were implanted for valve replacement in 50 patients at the Han Yang University Hospital. The operative procedures were as follow: Mitral valve replacement [MVR] in 25 patients, Mitral valve replacement [MVR] and Tricuspid valve [TV] annuloplasty in 7 patients, Aortic valve replacement [AVR] in 8 patients, Aortic valve replacement [AVR] and Mitral valve replacement [MVR] in 8 patients. Aortic valve replacement [AVR] and Mitral valve replacement [MVR] and Tricuspid valve [TV] annuloplasty in 2 patients. To evaluate the immediate hemodynamic changes after valve replacements, the pressures of each cardiac chamber and ulmonary artery were checked before and after valve replacement on the operation table. Right ventricle [RV] pressure was decreased from 52.09\ulcorner6.71 to 45.57\ulcorner5.03 mmHg, Pulmonary artery [PA] pressure was decreased from 45.97\ulcorner2.69 to 41.00\ulcorner3.99 mmHg, and Left atrium [LA] pressure was decreased from 30.33\ulcorner13.02 to 22.76\ulcorner.97 mmHg before and after valve replacement. In MVR group, RV pressure was decreased from 49.17\ulcorner7.89 to 43.14\ulcorner4.14 mmHg, PA pressure was decreased from 44.67\ulcorner3.18 to 38.67\ulcorner2.85 mmHg, and LA pressure was decreased from 31.46\ulcorner13.47 to 21.91\ulcorner.17 mmHg. In AVR group, RV pressure was decreased from 53.0\ulcorner7.44 to 44.71 \ulcorner3.24 mmHg, PA pressure was decreased from 34.83\ulcorner0.73 to 31.86\ulcorner.36 mmHg, and LA pressure was not changed. In double valve replacement [MVR and AVR] group, RV pressure was decreased from 57.50\ulcorner3.82 to 42.50\ulcorner.80 mmHg, PA pressure was decreased from 51.17\ulcorner1.42 to 43.33\ulcorner4.53mmHig, and LA pressure was decreased from 34.33\ulcorner2.09 to 25.50\ulcorner0.21 mmHg. But in the group where MVR and TV annuloplasty were performed, preoperative RV and PA pressure were markedly increased and no pressure decrease in RV and PA noticed after valve replacement. This study shows good immediate postoperative hemodynamic results after valve replacement using Ionescu-Shiley xenograft valve except in the cases of MVR and TV annuloplasty and advanced disease with pulmonary hypertension.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.20 no.12
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• pp.1340-1350
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• 2009

The design and implementation of planar Active Phased Array Antenna System are described in this paper. This Antenna system operates at X-band with its bandwidth 10 % and dual polarization is realized using dual slot feeding microstrip patch antenna and SPDT(Single Pole Double Through) switch. Array Structure is $16\times16$ triangular lattice structure and each array is composed of TR(Transmit & Receive) module with more than 40 dBm power. Each TR module includes digital attenuator and phase shifter so that antenna beam can be electronically steered over a scan angle$({\pm}60^{\circ})$. Measurement of antenna pattern is conducted using a near field chamber and the results coincide with the expected beam pattern. From these results, it can be convinced that this antenna can be used with control of beam steering and beam shaping.

• Journal of Conservation Science
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• v.30 no.4
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• pp.353-364
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• 2014

Formaldehyde(HCHO) may have a damage effect on Korean traditional textiles, because concentration is high and occurrence frequency is frequent at the exhibition room and storage area. Total 20 specimens were prepared using 4 different materials (silk, cotton, ramie, hemp) after dyeing with 5 colors (undyed, red, yellow, blue, black). The specimens were exposed to HCHO gas in the test chamber. The gas acceleration test was conducted to identify the deterioration of Korean traditional textiles according to HCHO concentration(0.5, 1, 10, 100, 500ppm), to temperature-humidity condition at HCHO 500ppm, and deterioration conditions at HCHO 500ppm. Optical, chemical, and physical evaluation was carried out after the exposure. The results, color difference, grey scale rating, formate($HCO_2{^-}$) of some textiles increased at 500ppm, while pH decreased at 500ppm. Also, color difference, grey scale rating, formate($HCO_2{^-}$) of some textiles increased double damage at high temperatures & humidity, high humidity condition. But, damages of accelerated degradation textiles were slight, because of degradation degree and degradation products. The results suggest that determined the damage to the korean traditional textile, damage level, damage-weighted condition, damage to accelerated degradation textiles. In addition, formaldehyde damaged to yellowing of red textiles, bleaching of accelerated degradation textiles, formic acid damaged to bleaching of total 20 specimens.