• Title/Summary/Keyword: $^{133}Cs$

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The Statistical Thermodynamic Approach to the Liquid-Vapor Interface of Binary Solution (이성분 용액의 액체-증기 계면에 대한 통계 열역학적 연구)

  • Hyungsuk Park
    • Journal of the Korean Chemical Society
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    • v.15 no.3
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    • pp.133-145
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    • 1971
  • A method of theoretical calculation of the thermodynamic properties for liquid-vapor interface of binary solution is developed according to the transient state theory of significant liquid structure. The surface tensions, the adsorbed amounts at the liquid-vapor interface and the activity coefficients of the components for the solutions of $C_6H_{12}-C_6H_6$ $CCI_4-C_6H_6$, $CHCl_3-C_6H_6$, $CHCl_3-CCl_4$, $CCl_4-CS_2$ are calculated through the full ranges of the compositions.

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Study on New Airworthiness Requirements of Powerplant System for the Small Airplane (소형 비행기 동력장치에 관한 신규 인증요건 분석)

  • Lee, Eunsuk;Lee, Seung geun;Lee, Kang-Yi
    • Journal of the Korean Society of Propulsion Engineers
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    • v.22 no.3
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    • pp.128-133
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    • 2018
  • Korean civil airworthiness requirements of powerplant system are regulated by KAS(Korean Airworthiness Standard) Part 23 and Part 33. These are equivalent to FAR Part 23, Part 33 of FAA, and CS-23 and CS-E of EASA. FAA and EASA rewrite the airworthiness requirements for small airplane. They changed current 'prescriptive regulation' to a 'performance-based regulation' which makes safety performance the objective. Powerplant requirements have also been changed extensively by this concept revolution. In accordance with this reorganization, we studied the new powerplant system requirements of FAR Part 23 and proposed ideal directions to rewrite the Korean Airworthiness Standard.

Development and Validation of Dithiocarbamates Fungicide Analytical Method using CS2 Trap Method in Livestock Product (축산물 중 CS2 포집방법을 이용한 Dithiocarbamate계 살균제 분석법 개발 및 검증)

  • Jo, Hyeong-Wook;Sun, Jung-Hun;Heo, Hyo-Min;Lee, Sang-Hyeob;Kim, Jang-Eok;Moon, Joon-Kwan
    • Korean Journal of Environmental Agriculture
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    • v.40 no.2
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    • pp.127-133
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    • 2021
  • BACKGROUND: Dithiocarbamte fungicides have been used in crop cultivation for diseases protection and treatment. And cultivated agricultrual products were used as feedstuff, and residual pesticides are likely to be absorbed and transferred to livestock. But the maximum residue limits (MRLs) were not established for dithiocarbate fungicides in livestock products, and thus an analysis method was developed and validated for dithiocarbamate fungicides to establish MRLs. METHODS AND RESULTS: Samples were prepared using CS2 trap method and detected with UV/VIS spectrophotometer. Calibration line (0.1 ~ 10 ㎍/mL) was linear with r2 > 0.99. For validation, the recovery tests were carried out at three fortification levels (MLOQ, 10 MLOQ and 50 MLOQ) from livestock samples (egg, milk, beef, pork, and chicken). The results for mancozeb, propineb, and thiram ranged between 76.8 to 109.6%, 79.4 to 108.8%, and 80.2 to 107.8%, respectively and % RSD (relative standard deviation) values were below 9.5%. Furthermore, inter-laboratory analysis was performed to validate the method. CONCLUSION: All values were corresponded with the criteria ranges requested by both the CODEX (CAC/GL 40-1993, 2003) and MFDS guidelines (2016). This might be used as an official analytical method for determination of dithiocarbamate fungicides at established MRLs and monitoring.

Development of a Wireless Gamma-ray Probe for Diagnosing and Evaluation of its Effectiveness (진단용 무선 감마선 프로브 개발 및 유용성 평가)

  • Park, Hyemin;Joo, Koansik
    • Journal of the Institute of Electronics and Information Engineers
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    • v.52 no.2
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    • pp.173-181
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    • 2015
  • We developed a wireless gamma-ray probe based on radiation photon counting method to diagnose and detect remaining lesions after surgery, and its effectiveness was evaluated using calibration sources and a phantom. The probe was designed and miniaturized using a semi-conductor-based radiation sensor, and a Bluetooth remote communication module was used to implement the wireless diagnosis and detection system. Moreover, a remote monitoring system was implemented to monitor affected areas during diagnosis and surgery. To assess the effectiveness of the developed probe in this study, calibration sources $^{57}Co$, $^{133}Ba$, $^{22}Na$ and $^{137}Cs$ and a chicken breast phantom were used. Furthermore, the probe's detection response to gamma ray was confirmed through evaluation. Its clinical applicability was verified by assessing the response linearity and detection direction according to gamma-ray intensity, as well as the detection efficiency according to the depth of the gamma source in the phantom.

Sorption Efficiency of the Bamboo Charcoal to Remove the Cesium in the Contaminated Water System (오염수계 내 세슘 제거를 위한 대나무 활성탄의 흡착효율 규명)

  • Ahn, Joungpil;Lee, Minhee
    • Economic and Environmental Geology
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    • v.51 no.2
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    • pp.87-97
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    • 2018
  • The cesium (Cs) removal from the contaminated water system has been considered to be difficult because the cesium likes to exist as soluble phases such as ion and complexes than the solid in water system. Many researches have focused on developing the breakthrough adsorbent to increase the cesium removal efficiency in water. In this study, the laboratory scale experiments were performed to investigate the feasibility of the adsorption process using the bamboo charcoal for the Cs contaminated water system. The Cs removal efficiency of the bamboo charcoal were measured and the optimal adsorption conditions were determined by the adsorption batch experiments. Total 5 types of commercialized bamboo charcoals in Korea were used to identify their surface properties from SEM-EDS and XRD analyses and 3 types of bamboo charcoals having large specific surface areas were used for the adsorption batch experiment. The batch experiments to calculate the Cs removal efficiency were performed at conditions of various Cs concentration (0.01 - 10 mg/L), pH (3 - 11), temperature ($5-30^{\circ}C$), and adsorption time (10 - 120 min.). Experimental results were fitted to the Langmuir adsorption isotherm curve and their adsorption constants were determined to understand the adsorption properties of bamboo charcoal for Cs contaminated water system. From results of SEM-EDS analyses, the surfaces of bamboo charcoal particles were composed of typical fiber structures having various pores and dense lamella structures in supporting major adsorption spaces for Cs. From results of adsorption batch experiments, the Cs-133 removal efficiency of C type bamboo charcoal was the highest among those of 3 bamboo charcoal types and it was higher than 75 % (maximum of 82 %) even when the initial Cs concentration in water was lower than 1.0 mg/L, suggesting that the adsorption process using the bamboo charcoal has a great potential to remove Cs from the genuine Cs contaminated water, of which Cs concentration is low (< 1.0 mg/L) in general. The high Cs removal efficiency of bamboo charcoal was maintained in a relatively wide range of temperatures and pHs, supporting that the usage of the bamboo charcoal is feasible for various types of water. Experimental results were similar to the Langmuir adsorption model and the maximum amount of Cs adsorption (qm:mg/g) was 63.4 mg/g, which was higher than those of commercialized adsorbents used in previous studies. The surface coverage (${\theta}$) of bamboo charcoal was also maintained in low when the Cs concentration in water was < 1.0 mg/L, investigating that the Cs contaminated water can be remediated up with a small amount of bamboo charcoal.

CHARACTERISTICS EVALUATION AND GROWTH OF $BI_4GE_3O_{12}$ SINGLE CRYSTAL BY CZOCHRALSKI METHOD

  • Cho, Yun-Ho;Kim, Yong-Kyun;Lee, Woo-Gyo;Kang, Byoung-Hwi;Kim, Jong-Kyung;Lee, Dong-Hoon;Park, Jae-Woo
    • Journal of Radiation Protection and Research
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    • v.34 no.2
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    • pp.83-86
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    • 2009
  • The single crystal scintillator of bismuth germinate ($Bi_4Ge_3O_{12}$:BGO) was successfully grown by the conventional Czochraski technique. The characteristics of the grown BGO were evaluated and presented on the excitation, emission responses and energy spectra of the $\gamma$-rays from $^{241}Am$, $^{133}Ba$, $^{57}Co$, $^{22}Na$, $^{137}Cs$ and $^{54}Mn$ radio-isotopes. The energy resolution of grown BGO, $\Delta$E/E, was estimated to be 12.1% at 662 keV of $\gamma$-ray for $^{137}Cs$ nuclide. Compared to the commercial BGO crystal, we confirmed that the grown BGO has a good performance and is comparable to reference one.

Airborne HPGe spectrometer for monitoring of air dose rates and surface activities

  • Marcel Ohera;Lubomir Gryc;Irena Cespirova;Jan Helebrant;Lukas Skala
    • Nuclear Engineering and Technology
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    • v.55 no.11
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    • pp.4039-4047
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    • 2023
  • This contribution describes the application of HPGe detector for the airborne quantitative analysis. The hardware of the airborne HPGe system was designed from the commercial components with only exception of the newly designed AirHPGeSpec special software to control, measure and process the data. The system was calibrated for the local air kerma rates measured on helicopter board and its conversion to the air kerma rates at 1 m above the ground was proposed. Two examples of the air kerma rates measured over the former uranium mining areas are presented and compared with the results of other airborne system on the board. This airborne HPGe system could be also used for measuring the surface activities in a radiation event. The nuclides of 131I, 132Te - 132I, 133I, 134I, 135I, 137Cs, 134Cs, 88Rb and 103Ru were selected from possible nuclear power plant emergency scenarios. The Monte Carlo simulation was used to calculate HPGe detector efficiencies for the flight altitudes from 25 to 300 m for the energies from 300 keV to 3 MeV of the nuclides in question. Also, the detection limits according to the Currie method as well as ISO 11929-2010 for selected nuclides are presented.

Potentiation of Anticancer Effect of Artesunate by Combination with Nonsteroidal Anti-inflammatory Drugs on Human Cancer Cells (Artesunate와 비스테로이드소염제 NSAID의 병용 처리에 의한 항암 활성 증강)

  • Moon, Hyun-Jung;Kang, Chi-Dug;Kim, Sun-Hee
    • Journal of Life Science
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    • v.31 no.10
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    • pp.873-884
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    • 2021
  • The purpose of present study is to investigate the role of artesunate (ART) in enhancing anticancer effect of nonsteroidal anti-inflammatory drug (NSAID) on human cancer cells, and we elucidate a possible molecular mechanism of this combination effect. We showed that the combined effect of ART with NSAID such as celecoxib (CCB) or dimethyl-CCB (DMC) in various type of human cancer cells. After ART treatment, the expression of p62, nuclear factor erythroid 2-like 2 (NRF2) and cancer stemness (CS)-related proteins including CD44, CD133, aldehyde dehydrogenase 1 (ALDH1), octamer-binding transcription factor 4 (Oct4), mutated p53 (mutp53) and c-Myc was down-regulated. ART induced autophagy as reduction of the autophagy receptor p62, which was associated with up-regulation of activating transcription factor 4 (ATF4) and C/EBP homologous protein (CHOP), and simultaneous down-regulation of NRF2 and CS-related proteins was occurred in the human cancer cells. These results indicate a possibility that ART activates autophagy through ATF4-CHOP cascade leading to down-regulation of CS-related proteins and subsequently eradicated cancer stem cells. In addition, co-treatment with ART and imatinib was more effective than either drug alone on growth inhibition and apoptosis induction of cancer cells. In conclusion, induction of autophagy-dependent cell death by ART might play a critical role in mediating the synergistic effect of drug combination (ART/NSAID and ART/imatinib). Therefore, ART could be a promising candidate as a chemosensitizer to enhance the anticancer effects of NSAID and imatinib.

The spectrum of 5p deletion in Korean 20 patients with Cri du chat syndrome (한국인 묘성증후군 20명 환자에서의 5p 결실 양상 분석)

  • Park, Sang-Jin;Kim, Sook-Ryung;Baek, Kum-Nyeo;Yoon, Joon-No;Jeong, Eun-Jeong;Kown, Ji-Eun;Kim, Hyon-J.
    • Journal of Genetic Medicine
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    • v.4 no.2
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    • pp.133-141
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    • 2007
  • Purpose : Cri-du-Chat syndrome (CdCs) is a rare but clinically recongnizable condition with an estimated incidence of 1:50,000 live births. The clinical characteristics of the syndrome include severe psychomotor and mental retardation, microcephaly, hypertelorism, hypotonia, and slow growth. Also the size of the chromosome 5p deletion ranges were known from the region 5p13 to the terminal region. In this study, we report the spectrum of 5p deletion in Korean 20 pts. with CdCs and genotype-phenotype associations in CdCs. Methods : In order to delineate genotype-phenotype correlation, molecular cytogenetic studies including GTG banding and clinical characterization were performed on Korean 20 pts with CdCs including parents. CGH array and Fluorescence in situ hybridization (FISH) analysis were used to confirm a terminal deletion karyotype and map more precisely the location of the deletion breakpoint. Results : Molecular analysis of the spectrum of 5p deletion revealed 9 pts (45%) with a del (5)(p14), 7 pts. (35%) a del (5)(p13), 3 pts. (15%) a del (5)(p15.1) and 1 pt. (5%) a del (5)(p15.2) in 20 pts with CdCs. 4(20%)pts were identified to have additional chromosome abnormalites of deficiency and duplication involving chromosomes of 6, 8, 18, & 22. Parental study identified 3 familial case (2 paternal and 1 maternal origin) showing parents being a balanced translocation carrier. And the comparison study of the deletion break points among these 20 pts. with their phenotype has showed the varying clinical pheno-types in the CdCs critical region. Conclusion : The characterization of 5p deletion including parental study may help to delineate the genotypephenotype correlation in CdCs. Also these molecular cytogenetic analyses will be able to offer better information for accurate genetic diagnosis in CdCs and further make possible useful genetic counseling in pts. and family.

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A Study on the Development of Nuclear Radiation Detector with Silicon PIN Photodiode (실리콘 포토다이오드를 이용한 방사선 검출기 개발에 관한 연구)

  • Yi, Un-K.;Kim, Jung-S.;Sohn, Chang-H.;Baek, Kwang-R.
    • Proceedings of the KIEE Conference
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    • 1999.11c
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    • pp.754-756
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    • 1999
  • In this paper, we have developed a high-sensitivity SNRD(Semiconductor Nuclear Radiation Detector) using silicon PIN photodiode. The SNRD is constructed with silicon PIN photodiode(S3590-05), preamplifier and shaping amplifier. To show the effectiveness of SNRD, nuclear radiation experiments are conducted with $\gamma$-ray Ba-133, Cs-137 and Co-60. The SNRD is different in characteristics of the energy spectrum to scintillation detectors. However, the SNRD have a good linearity on $\gamma$-ray energy and activity. The results of this paper can be applied to electronic personal dosimeter.

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