• 제목/요약/키워드: Exposure Experiment

검색결과 802건 처리시간 0.029초

벼의 종실 발육단계에 따른 주간 및 야간 HTO 증기 피폭시 TFWT 및 OBT 농도 (TFWT and OBT Concentrations in Rice Plants Exposed to HTO Vapor during Daytime and Nighttime at Different Seed-Developing Stages)

  • 최용호;임광묵;이원윤;강희석;최희주;이한수;실비아디아바테;지그프리드슈트락
    • Journal of Radiation Protection and Research
    • /
    • 제28권1호
    • /
    • pp.9-18
    • /
    • 2003
  • 벼를 쌀알의 발육단계별로 주간 및 야간에 1 시간 동안 HTO 증기에 피폭시키고 작물체 부위별로 조직자유수 $^3H$ (TFWT) 및 유기결합형 $^3H$ (OBT) 농도를 조사하였다. 피폭종료 직후$(h_0)$ 잎의 TFWT 농도는 주간실험에서는 공기수분중 1 시간 평균 HTO 농도의 100% 내외였으나 야간실험에서는 $30{\sim}40%$에 불과하였다. 주 야간 피폭 모두 TFWT 농도는 초기에는 급히 감소하다가 나중에는 훨씬 천천히 감소하였고 수확시에는 $h_0$에 비해 수백${\sim}$수만 배 낮았다. OBT 농도는 부위 및 피폭시기에 따라 변화양상이 달랐고 $h_0$와 수확시 간 차이는 대체로 10 배 이내였다. 야간피폭 중에도 주간피폭의 약 1/3 수준으로 OBT가 생성되었다. 공기중 HTO의 수확시 쌀알내 OBT로의 전환 정도는 주간피폭시 야간피폭보다 수 배 높았고 주 야간 피폭 모두 쌀알의 발육 최성기 피폭시에 가장 높았다. 벼가 쌀알의 발육기에 HTO에 피폭되면 OBT에 의한 섭취피폭선량이 TFWT보다 훨씬 클 것으로 추정되었다.

Aerobic Stability and Effects of Yeasts during Deterioration of Non-fermented and Fermented Total Mixed Ration with Different Moisture Levels

  • Hao, W.;Wang, H.L.;Ning, T.T.;Yang, F.Y.;Xu, C.C.
    • Asian-Australasian Journal of Animal Sciences
    • /
    • 제28권6호
    • /
    • pp.816-826
    • /
    • 2015
  • The present experiment evaluated the influence of moisture level and anaerobic fermentation on aerobic stability of total mixed ration (TMR). The dynamic changes in chemical composition and microbial population that occur after air exposure were examined, and the species of yeast associated with the deterioration process were also identified in both non-fermented and fermented TMR to deepen the understanding of aerobic deterioration. The moisture levels of TMR in this experiment were adjusted to 400 g/kg (low moisture level, LML), 450 g/kg (medium moisture level, MML), and 500 g/kg (high moisture level, HML), and both non-fermented and 56-d-fermented TMR were subjected to air exposure to determine aerobic stability. Aerobic deterioration resulted in high losses of nutritional components and largely reduced dry matter digestibility. Non-fermented TMR deteriorated during 48 h of air exposure and the HML treatment was more aerobically unstable. On dry matter (DM) basis, yeast populations significantly increased from $10^7$ to $10^{10}cfu/g$ during air exposure, and Candida ethanolica was the predominant species during deterioration in non-fermented TMR. Fermented TMR exhibited considerable resistance to aerobic deterioration. Spoilage was only observed in the HML treatment and its yeast population increased dramatically to $10^9cfu/g$ DM when air exposure progressed to 30 d. Zygosaccharomyces bailii was the sole yeast species isolated when spoilage occurred. These results confirmed that non-fermented and fermented TMR with a HML are more prone to spoilage, and fermented TMR has considerable resistance to aerobic deterioration. Yeasts can trigger aerobic deterioration in both non-fermented and fermented TMR. C. ethanolica may be involved in the spoilage of non-fermented TMR and the vigorous growth of Z. bailii can initiate aerobic deterioration in fermented TMR.

원자력안전법에 대한 방사선학과 학생들의 학습권 보장에 관한 연구 (A Study on the Guarantee of Learning Rights of Radiology Students in Nuclear Safety Act)

  • 이보우
    • 대한방사선기술학회지:방사선기술과학
    • /
    • 제45권2호
    • /
    • pp.159-164
    • /
    • 2022
  • The study developed a radiation dose measurement program in the radiology laboratory to measure how much exposure the students are exposed to during the radiology class, to request for the improvement and the revision of the current Nuclear Safety Act. The experimental program is shown in the following figure, and experiments were conducted to determine the degree of radiation exposure in the control room with a lead gown at a distance of 1 m, 2 m, and 1 m, and in a control room with a radiographic lead glass wall. The duration of the experiment was 3 months from April to June, when radiation imaging practice classes were conducted, and 128 hours of imaging practice per month were conducted. In order to find out the dose of radiation dose during radiology imaging practice class, the experiment was carried out from April to June for 3 months, and according to the program, the results of exposure dose were 0.34 mSv at 1 m distance, 0.01 mSv at shielding of lead gown at 1 m distance, 0.16 mSv at 2 m distance, and 0.01 mSv at control room with radiation lead glass wall. The exposure dose from the test results was much below the annual general public limit dose of 1 mSv. The restriction on the operation of the radiation equipment in the practice of the students is a regulation that infringes the right of students to learn, and amendments or exemptions of Nuclear Safety Act should be enacted to ensure that it does not violate the fundamental right to learn for students in radiology.

흡연과 낮은 방사선 피폭량이 Lymphocyte DNA 손상에 미치는 영향 (The Influence of Smoking and Low Dose Radiation Exposure to the Damage of the Lymphocyte DNA)

  • 신현길;김윤주;권은혜;육진영;최수용
    • Environmental Analysis Health and Toxicology
    • /
    • 제18권4호
    • /
    • pp.237-242
    • /
    • 2003
  • Single cell gel electrophoresis (SCGE) was used to the experiment with the variation on the amount of smoking and low dose radiation exposure to find how much the Lymphocyte DNA was damaged, and especially for whom smoke a lot(about 20 or more than 20 cigarettes a day) it was found to be highly damaged. While, the damage of 'not more than 20 cigarettes a day' was found to be not so much significant as like for whom smoke about or more than 20 cigarettes a day And, according to the different amount of the radiation exposure, the Lymphocyte DNA was found to be considerably damaged for 0-13m Sv (P<0.01), it was not able to prove the relationship between the DNA damage and the radiation exposure.

Maternal Exposure to Bisphenol A Impacts on Fecundity in F1 and F2 Generations in Drosophila melanogaster

  • Kim, Sohee;Kang, Kyong-hwa;Koh, Hyongjong
    • 한국발생생물학회지:발생과생식
    • /
    • 제25권3호
    • /
    • pp.193-197
    • /
    • 2021
  • In previous reports, bisphenol A (BPA) exposure affects reproductive function in Drosophila melanogaster females. To test the maternal effect of BPA exposure on fly reproductive function, F0 mothers were exposed to 0, 0.1, 1, and 10 mg/L of BPA and the fecundity in F1 and F2 generations were checked. In this experiment, 1 and 10 mg/L BPA significantly decreased the fecundity of F1 females. Moreover, 0.1 and 1 mg/L BPA substantially reduced egg production in the F2 generation. These results suggested that maternal exposure to BPA at enviromentally relavant concnetrations reduces reproductive function in Drosophila melanogaster females and that this effect is transgenerational.

동물 염색체 분리를 위한 최적 혈액배양 조건에 관한 연구 (Methodology of Lymphocytes Culture for Animal Chromosome Preparation)

  • 손시환;이정업
    • Reproductive and Developmental Biology
    • /
    • 제35권3호
    • /
    • pp.257-263
    • /
    • 2011
  • In general, the blood cell culture is a common method for animal chromosome preparation. However, every animal and its cells have unique physiological characteristics and functions. Hence, it is very difficult to find the suitable method of chromosome preparation using animal lymphocyte culture. This study was carried out to fine the suitable method of chromosome preparation using lymphocytes cultures in mammalians and aves including cattle, rat, mouse and chicken. To seek the optimal method of lymphocyte culture in each animal, $2^3$ factorial experiment was designed. The design evaluated three main effects in culture duration, kinds of mitogen supplements and colcemid exposure time with two levels within each effect. The mitotic index and the score of chromosome morphology were analyzed. In results, the suitable methods of lymphocyte culture for chromosome preparation were 72 hours culture, pokeweed mitogen(PWM) supplement and 90 minutes of colcemid exposure in cattle, 72 hours culture, PWM supplement and 50 minutes of colcemid exposure in chicken, 96 hours culture, concanavalin A supplement and 90 minutes of colcemid exposure in rat, and 72 hours culture, PWM supplement and 50 minutes of colcemid exposure in mouse, respectively. In conclusion, kinds of mitogen, culture duration and colcemid exposure time significantly affected the mitotic index and chromosome morphology, in animal lymphocyte culture. The interaction effects between/among treatment factors were also statistically significant.

홀로그래픽 저장장치의 각/프랙탈 다중화 방식에서 균일한 회절 효율을 위한 기록 시간 분배 (The exposure-time schedule for uniform diffraction efficiency in angle/fractal multiplexing of holographic data storage)

  • 이재성;최진영;박영필;양현석;박노철
    • 정보저장시스템학회:학술대회논문집
    • /
    • 정보저장시스템학회 2005년도 추계학술대회 논문집
    • /
    • pp.139-144
    • /
    • 2005
  • Because of the photorefractive recording dynamics, each newly recorded hologram partially erases all previously stored image. Thus achieving the desired diffraction efficiency profile for the entire sequence after all images have been recorded requires exposure time schedule. The often cited classical exposure-schedule model predicts a rising-exponential build-up and an exponential decay in An with an exposure time. However because we cannot directly measure the An, it's difficult to establish the relation of both. In this paper, we deduce the relation of diffraction efficiency and exposure time from experiment data and suggest an algorithm to make time schedule profile in angle/fractal multiplexing of holographic data storage. After that, we present simulated result with equal hologram diffraction efficiency for a sequence of 250 holograms recorded by angle/fractal multiplexing.

  • PDF

Monitoring of Initial Stages of Atmospheric Zinc Corrosion in Simulated Acid Rain Solution under Wet-dry Cyclic Conditions

  • EL-Mahdy, Gamal A.;Kim, Kwang B.
    • Corrosion Science and Technology
    • /
    • 제3권6호
    • /
    • pp.251-256
    • /
    • 2004
  • Exposure of zinc samples in simulated acid rain solution (SARS) was investigated under a periodic wet-dry conditions using an AC impedance technique. The periodic wet and dry exposure consisted of the immersion of zinc samples in SARS for one hour followed by exposure to 7 hours drying at 60% RH. Phases of the corrosion products were indentified by X-ray diffraction (XRD). The influence of relative humdiity (RH), temperature, and surface inclination on the atmospheric corrosion of zinc is described. The reciprocal of polarization resistance (1/Rp) decreases rapidly during the initial stages then slowly and eventually attains a steady state as exposure time progresses. The average of reciprocal of polarization resistance per cycle, (ARPR) was calculated and found to decrease as number of exposure cycle increases. An increase of temperature enhances the corrsion rate of zinc. The values of ARPR, of a sample inclined at 30 o are lower than those for a sample oriented horizontally. The experiment result shows a pronounced dependence of reciprocal of polarization resistance on RH. Exposure in the presence of carbonate anions gives rise to more protective corrosion products than in nitrate anion solution. The corrosion mechanism during the initial stages of atmospheric zinc corrosion under wet-dry cyclic conditions is suggested.

Characterization of Low-temperature SU-8 Negative Photoresist Processing for MEMS Applications

  • May Gary S.;Han, Seung-Soo;Hong, Sang-Jeen
    • Transactions on Electrical and Electronic Materials
    • /
    • 제6권4호
    • /
    • pp.135-139
    • /
    • 2005
  • In this paper, negative SU-8 photoresist processed at low temperature is characterized in terms of delamination. Based on a $3^3$ factorial designed experiment, 27 samples are fabricated, and the degree of delamination is measured for each. In addition, nine samples are fabricated for the purpose of verification. Employing the. neural network modeling technique, a process model is established, and response surfaces are generated to investigate degree of delamination associated with three process parameters: post exposure bake (PEB) temperature, PEB time, and exposure energy. From the response surfaces generated, two significant parameters associated with delamination are identified, and their effects on delamination are analyzed. Higher PEB temperature at a fixed PEB time results in a greater degree of delamination. In addition, a higher dose of exposure energy lowers the temperature at which the delamination begins and also results in a larger degree of delamination. These results identify acceptable ranges of the three process variables to avoid delamination of SU-8 film, which in turn might lead to potential defects in MEMS device fabrication.

Tensile Properties of Hybrid Fiber-Reinforced Reactive Powder Concrete After Exposure to Elevated Temperatures

  • Li, Haiyan;Liu, Gang
    • International Journal of Concrete Structures and Materials
    • /
    • 제10권1호
    • /
    • pp.29-37
    • /
    • 2016
  • The paper presents a research project on the tensile properties of RPC mixed with both steel and polypropylene fibers after exposure to $20-900^{\circ}C$. The direct and the indirect tensile strength (in bending) were measured through tensile experiment on dog-bone specimens and bending experiment on $40{\times}40{\times}160mm$ prisms. RPC microstructure was analyzed using scanning electron microscope. The results indicate that, steel fibers can significantly improve the tensile performance of hybrid fiber-reinforced RPC, whereas polypropylene fibers have no obvious effect on the tensile performance. With increasing temperature, the flexural and axial tensile strength of hybrid fiber-reinforced RPC substantially decrease linearly, which attributes to the deteriorating microstructure. Based on the experimental results, equations are established to express the decay of the flexural and tensile strength with increasing temperature.