• Applied Microscopy
• /
• 제23권2호
• /
• pp.11-26
• /
• 1993

This experiment was performed to study the morphological responses of the pigment epithelial cell and the Bruch's membrane of the retina of rat following X-ray irradiation. Male rats were divided into normal and experimental groups. The heads of the rats, under sodium thiopental anesthesia, were exposed to 3,000 rads or 6,000 rads of radiation in a single dose, respectively. The source was a Mitsubishi Linear Accelerator ML-4MV. The target to skin distance was 80cm, and the. dose rate was 200 rads/min. The experimental groups were sacrificed on the 6th hour, 2nd and 6th day after X-ray irradiation. Under anesthesia, 1% glutaraldehyde-1% paraformaldehyde solution(0.1M Millonig's phosphate buffer, pH 7.3) was perfused through the left ventricle and ascending aorta. Pieces of the tissue taken from the posterior region of the retina were fixed in 2.5% glutaraldehyde-1.5% paraformaldehyde(0.1M Millonig's phosphate buffer, pH 7.3) and 1% osmium tetroxide(0.1M Millonig's phosphate buffer, pH7.3), and embedded in araldite mixture. The ultrathin sections contrasted with uranyl acetate and lead citrate were observed with JEM 100 CX-II electron microscope. The results were as follow; 1. The morphological changes of the pigment epithelial cells were not pronounced after exposure to 3,000 rads of X-ray. But on the 6th hour after exposure to 6,000 rads of X-ray, bulging nuclear membrane protruding into the cytoplasm and nuclear chromatin clumped into numerous masses along the nuclear membrane were observed. At the 2nd and 6th day post-irradiation, partial cytolysis or necrosis were seen. 2. The thickness of the Bruch's membrane of the experimental groups were increased in the time and dose range covered by this study, and splitting or diffusing basal laminae of the choriocapillary layer were observed frequently in the experimental group. Above results suggest that large amount(6,000 rads) of head irradiation induce direct hazardous effects on the pigment epitherial cells and Bruch's membrane of the retina of the rat, but pigment epithelial cells are more radioresistant than Bruch's membrane.

• 대한방사선기술학회지:방사선기술과학
• /
• 제20권2호
• /
• pp.49-55
• /
• 1997

This study was carried out to investigate radiographical and operating conditions of X-ray units and exposure doses to patients during chest radiography, so that the results could provide basic data used for reducing the exposure dose and for providing the diagnostic information with better quality. The conditions and exposure doses of 100 X-ray units mainly used for chest radiography were examined and also 100 radiological technologists mainly handling those apparatus at 76 medical facilities in Pusan were surveyed using a questionnaire from October 1 to December 31 in 1995. The following results were obtained from the study : 1. It was found that most units were capable of taking a high tube voltage radiography by showing 67% of the units equipped with the maximum tube voltage of 150 kV, 94% with more than 500 mA for the rating capacity and 85% with the full wave type of a signal phase. 2. For actual chest radiographical conditions, however, 80% of the units were operated at $60{\sim}100\;kVp$ and only 14% at 100 kVp and over for the high tube voltage. 3. The average exposure time was less than 0.1 second, and eighty four percent of the units adapted the X-ray tube currents ranging from 200 to 300 mA, 80% the focus-film distances between 180 and 210 cm, and 63% the focus sizes of more than 2.0 mm. 4. Most units(98%) employed additional filters made of aluminum, 75% the thickness of filters less than 2.0 mm, and only 2 units the compound filters. 5. Ortho chromatic system was only adopted in 13% of screen film system for the units, and 73% used the grid ratio at 8 : 1 for the low tube voltage during chest radiography. 6. The average exposure dose of all X-ray units during chest radiography was $371\;{\mu}Sv$ with a difference of about 16 times between the minimum to the maximum, and $386\;{\mu}Sv$ both at hospitals and at health centers, followed by $380\;{\mu}Sv$ at general hospitals and $263\;{\mu}Sv$ at university hospitals without showing any statistically significant differences. In conclusion, since patients during chest radiography at medical facilities in Pusan exposed to high levels of radiation, it is recommended that appropriate added filters and grids necessary for the high tube voltage radiography and high-speed screen systems should be adopted and used as soon as possible in order to reduce exposure dose to the patients.

• 화훼연구
• /
• 제18권3호
• /
• pp.157-164
• /
• 2010

국화는 개화를 위해서는 30일의 지속적인 단일 처리가 요구되는 원예작물인데 본 연구에서는 국화의 화형별 홑꽃 타입의 'Limelight', 'sunlight', 'Candle Light', 'Firebrand', 'Twilight'와 겹꽃 타입의 'Spirit', 'Sunburst Spirit', 'Mandalay', 'Illini Harvest'가 단일 (SD)-장일 (LD)-단일 (SD)의 일장 처리가 생장 및 개화조절 반응에 미치는 효과를 알아보고자 수행되었다. 30일간의 단일처리와 5일 또는 10일 동안의 장일처리 후 5일 또는 10일 동안의 단일조건을 각각 처리하였다. 품종별 차이는 없었으나 5 SD-10 LD-25 SD 처리는 개화를 지연시키고 설상화 수가 증가되었다. 특히 'Firebrand'와 'Candlelight' 품종의 설상화 수는 각각 40개와 60.8개로 대조구에 비해 현저히 증가되었다. 또한 SD-LD-SD처리는 개화를 6일에서 7일정도 지연시키는 것 외에는 큰 효과를 나타나지 않았다. 그러나 'Illini Harvest'와 'Limelight의 설상화 수는 어떤 SD-LD-SD 처리에 의해서도 증가되지 않았다. 따라서 추후 새로운 품종별 일장처리에 따른 추가적인 연구 분석이 뒤따라야 할 것으로 판단되며 본 연구 결과는 국화의 신품종 육성을 위한 자료에 유용함을 알 수 있었다.

• 대한전기학회:학술대회논문집
• /
• 대한전기학회 1999년도 하계학술대회 논문집 D
• /
• pp.1992-1994
• /
• 1999

Dicumyl peroxide (DCP) is used for crosslinking agent in general. And the correlation between polyethylene and DCP is significant in particular radiation environment. On this paper, The effects on $Co^{60}{\gamma}$-ray irradiation of polyethylene doped dicumyl peroxide(DCP) were investigated. We experimented on electrical properties as following; electrical tree inception and growing type for applying AC step voltage, AC breakdown strength, volume resistivity, capacitance and dissipation factor at high frequency as increasing dosage. Also, chemical analysis was performed TGA, gel content.

• Mycobiology
• /
• 제40권2호
• /
• pp.145-146
• /
• 2012

The root of Hibiscus syriacus (Malvaceae) has been used for treatment of fungal diseases such as tinea pedis (athlete's foot). In this study, we investigated the antifungal constituent of the root of Hibiscus syriacus Ggoma, which was produced by a mutation breeding using gamma ray irradiation, and compared the antifungal activity of H. syriacus Ggoma and its parent type. According to the results, the methanolic extract of H. syriacus Ggoma exhibited four times higher antifungal activity than its parent type against Trichophyton mentagrophytes. Following purification through various column chromatographies, the antifungal substance was identified as nonanoic acid on the basis of spectroscopic analysis.

• ETRI Journal
• /
• 제25권6호
• /
• pp.517-522
• /
• 2003

This investigation confirms that silver stearate consists of an infinite-sheet, two-dimensional, nonmolecular layered structure. Scanning electron microscopy, X-ray diffraction, and infrared spectroscopy reveal the following: plate-like morphology is identified from the SEM image, XRD peaks can be indexed to the (0k0) reflections of a layered structure, and infrared peaks show that alkyl chains are present in an all-trans conformational state with little or no significant gauche population. Based on these structural characteristics, we demonstrate that silver stearate, a prototype of layered organic-inorganic hybrid material, can be grown not only in a designed two-dimensional pattern but also in three-dimensionally ordered ways by using carboxyl-group terminated nanoparticles as a template.

• Fisheries and Aquatic Sciences
• /
• 제18권3호
• /
• pp.297-300
• /
• 2015

This is the first report of Champsodon longipinnis (Champsodontidae) collected from Korea. The specimen (100.9 mm in standard length) was caught by a bottom trawl in the coastal waters off Busan, Korea. This species is characterized by the following morphological traits: body with small denticulate scales except abdomen around pelvic fin base; posterior end of maxilla extending beyond margin of eye; dark pigmentation on most of the first dorsal fin, upper half of the first to the fourth soft ray of the second dorsal fin, and partial upper lobe of caudal fin. We add C. longipinnis to the Korean fish fauna and suggest a new Korean name, "Jeom-ak-eo-chi," for the species.

• 치과방사선
• /
• 제8권1호
• /
• pp.23-27
• /
• 1978

The purpose of the present investigation is to determine how frequently radiopaque zones are seen on standard intraoral films and to research some other things about radiopaque zones. This study obtained the following results: 1. According to the standard intraoral films of the charts that were kept at the Dept. of Oral Diagnosis in Seoul National University Hospital, radiopaque zones were found in the rate of 4.1% among 1150 cases of amalgam-restored teeth that were treated at least two years ago. 2. Out of teeth that possessed radiopaque zones, 38.3% had radiolucent area between amalgam restoration and radiopaque zone. 3. Out of teeth that possessed radiopaque zones, 36.2% had cement base between amalgam restoration and radiopaque zone. 4. Out of teeth that possessed radiopaque zones, no tooth had periapical radiolucency. 5. Radiopaque zones were found more frequently in the mandibular teeth than the maxillary teeth. 6. According to the result of direct x-ray taking of 50 teeth that were treated at least 2 years ago, 6% had radiopaque zone.

• 한국진공학회지
• /
• 제7권s1호
• /
• pp.190-196
• /
• 1998

Amorphous ternary $Si_xC_yN-z$ thin films were obtained by plasma enhanced chemical vapor deposition(PECVD) using $N_2, SiH_4 \;and \;C_2H_4$ as the reaction sources. The chemical state were characterized by x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy(FTIR). The optical properties of the thin films were investigated by UV-visible spectrophotometer and ellipsometer, and the optical band gaps of thin films were determined from corresponding transmittance spectra following Tauc equation.

• Journal of Chest Surgery
• /
• 제35권4호
• /
• pp.311-314
• /
• 2002

간헐적 우측 흉부 동통을 호소하는 48세 남자 환자로 단순 흉부 방사선 촬영상 우측 중폐야에 거대 종괴가 관찰되어 우측 쌍폐엽 절제술 후 대세포 신경 내분비 암으로 진단되어진 1예를 치험 하였기에 문헌 고찰과 함께 보고하는 바이다.