• Journal of Electrical Engineering and Technology
• /
• 제13권6호
• /
• pp.2545-2552
• /
• 2018

$SF_6$ has been widely used in high voltage power equipment, such as gas insulated switchgear (GIS) and gas insulated transmission line (GIL), because of its excellent insulation and arc extinguishing performance. However, $SF_6$ faces two environmental problems: greenhouse effect and high liquefaction temperature. Therefore, to find the $SF_6$ substitute gases has become a research hotspot in recent years. In this paper, the liquefaction characteristics of $SF_6$ substitute gases were studied. Peng-Robinson equation of state with the van der Waals mixing rule (PR-vdW model) was used to calculate the dew point temperature of the binary gas mixtures, with $SF_6$, $C_3F_8$, $c-C_4F_8$, $CF_3I$ or $C_4F_7N$ as the insulating gas and $N_2$ or $CO_2$ as the buffer gas. The sequence of the dew point temperatures of the binary gas mixtures under the same pressure and composition ratio was obtained. $SF_6/N_2$ < $SF_6/CO_2$ < $C_3F_8/N_2$ < $C_3F_8/CO_2$ < $CF_3I/N_2$ < $CF_3I/CO_2$ < $c-C_4F_8/N_2$ < $C_4F_7N/N_2$ < $c-C_4F_8/CO_2$ < $C_4F_7N/CO_2$. $SF_6/N_2$ gas mixture showed the best temperature adaptability and $C_4F_7N/CO_2$ gas mixture showed the worst temperature adaptability. Furthermore, the dew point temperatures of the $SF_6$ substitute gases at different pressures and the upper limits of the insulating gas mole fraction at $-30^{\circ}C$, $-20^{\circ}C$ and $-10^{\circ}C$ were obtained. The results would supply sufficient data support for GIS/GIL operators and researchers.

• Journal of Microbiology and Biotechnology
• /
• 제29권9호
• /
• pp.1470-1477
• /
• 2019

${\beta}_2$-adrenergic receptor (${\beta}_2-AR$) was expressed efficiently using Bac-to-Bac Baculovirus Expression System in Sf9 cells as a bio-recognition element for multianalyte screening of ${\beta}$-agonist residues in pork. Sf9 cells were selected as the expression system, and codon optimization of wild-type nucleic acid sequence and time-dependent screening of expression conditions were then carried out for enhancing expression level and biological activity. Under optimum conditions of multiplicity of infection (MOI) = 5 and 48 h post transfection, the protein yield was up to 1.23 mg/ml. After purification by chromatographic techniques, the purified recombinant protein was applied to develop a direct competitive enzyme-linked receptor assay (ELRA) and the efficiency and reliability of the assay was determined. The IC50 values of clenbuterol, salbutamol, and ractopamine were 28.36, 50.70, and $59.57{\mu}g/l$, and clenbuterol showed 47.61% and 55.94% cross-reactivities with ractopamine and salbutamol, respectively. The limit of detection (LOD) was $3.2{\mu}g/l$ and the relevant recoveries in pork samples were in the range of 73.0-91.2%, 69.4-84.6%, and 63.7-80.2%, respectively. The results showed that it had better performance compared with other present nonradioactive receptorbased assays, indicating that the genetically modified ${\beta}_2-AR$ would have great application potential in detection of ${\beta}$-agonist residues.

• Journal of Electrical Engineering and Technology
• /
• 제13권6호
• /
• pp.2402-2411
• /
• 2018

Fluoronitriles-$CO_2$ gas mixtures are promising alternatives to $SF_6$ in environmentally-friendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-$CO_2$ mixture was obtained and compared with those of GILs filled with $CO_2$ and $SF_6$. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-$CO_2$ gas mixture was better than that of $CO_2$ but worse than that of $SF_6$. When compared with $SF_6$, use of the Fluoronitriles-$CO_2$ gas mixture caused a reduction in the GIL's current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-$CO_2$ gas mixtures.

• 한국노년학
• /
• 제30권3호
• /
• pp.683-694
• /
• 2010

본 연구는 아쿠아로빅 운동이 노년 여성에게 미치는 신체적, 심리적 효과를 동시에 관찰함으로써, 노인운동처방에 관한 다각도적인 기초자료를 제공하고자 하였다. 본 연구의 피험자는 I시 Y구 보건소 아쿠아로빅 운동프로그램에 참가를 희망하는 60-70대 노년 여성으로 운동군 25명, 통제군 30명으로 분류하였다. 아쿠아로빅 운동은 8주 동안 주 2회 최대여유심박수 40~70%의 운동강도로 실시하여, 운동 전후의 신체구성, 체력 및 건강관련 삶의 질(SF-36)의 변화를 측정하였다. 아쿠아로빅 운동 전후 신체구성의 체중(p=0.044), 체질량지수(p=0.038) 및 체지방률(p=0.005)의 모든 변인에서 시점에 따라 집단 간에 유의한 차이가 나타났다. 체력변인의 의자에서 일어섰다 앉기, 의자앉아 앞으로 굽히기는 시점에 따라 집단 간에 유의한 차이가 나타나지 않았으나, 2분 제자리걷기(p=0.002), 덤벨들기(p=0.005), 등 뒤에서 손잡기(p=0.023), 244cm 왕복걷기(p<0.001)는 시점에 따라 집단 간에 유의한 차이가 나타났다. 건강관련 삶의 질(SF-36)의 신체기능, 신체역할제한, 감정역할제한, 사회적 기능, 정신건강, 피로는 시점에 따라 집단 간에 유의한 차이가 나타나지 않았으나, 신체통증(p=0.039)과 일반적인 건강(p=0.024)은 시점에 따라 집단 간에 유의한 차이가 나타났다. 노년 여성에게 있어서 아쿠아로빅 운동은 신체구성의 개선과 체력의 향상을 위한 좋은 운동형태가 될 수 있음을 확인할 수 있었으나, 건강관련 삶의 질(SF-36)에 관하여서는 8가지 요인 중 2가지의 일부 요인에서만 긍정적인 영향이 나타났음을 확인할 수 있었다.

• 천문학회보
• /
• 제38권1호
• /
• pp.38.1-38.1
• /
• 2013

We present observational estimation of the infrared (IR) luminosity function (LF) of local (z < 0.3) star-forming (SF) galaxies derived from the AKARI NEP-Wide samples. We made an analysis of the NEP-Wide data with optical spectroscopic information allowing an accurate determination of luminosity function. Spectroscopic redshifts for about 1650 objects were obtained with MMT/Hectospec and WIYN/Hydra, and the median redshifts is about 0.22. To measure the contribution of SF galaxies to the luminosity function, we excluded AGN sample by comparing their SEDs with various model template. Spectroscopic redshifts and the AKARI's continuous filter coverage in the mid-IR (MIR) wavelength (2 ~ 25 micron) enable us to avoid large uncertainties from the mid-IR SED of galaxies and corresponding k-corrections. The 8-micron luminosity function shows a good agreement with the previous works in the bright-end, whereas it seems not easy to constrain the faint-end slope. The comparison with the results of the NEP-Deep data (Goto et al. 2010) suggests the luminosity evolution to the higher redshifts, which is consistent with the down-sizing evolutionary pattern of galaxies.

• 한국학교보건학회지
• /
• 제22권1호
• /
• pp.73-83
• /
• 2009

Purpose: The purpose of this study was to develop a comprehensive health promotion program for North Korean young adult defectors in South Korea. Methods: The comprehensive health promotion program consisted of nutrition, mental healthcare, physical activity and sexual behavior was developed on the basis of need assessment results. For the evaluation of the program, 70 North Korean young adults who were attending two alternative schools for North Korean defectors were recruited. The program had taken place once a week for 13 or 19 weeks. Effectiveness of the health promotion program was evaluated using anthropometric measurement, 3-day food records and a questionnaires that comprised the Hospital Anxiety and Depression Scale (HADS), the Short Form with 36 questions (SF-36) and health behaviors. The surveys were proceeded at the beginning and after the program. Results: After health promotion program, participants' height was significantly increased (p=0.004) and body fat mass (0=0.004) and percentage of body fat mass (p=0.003) were significantly decreased. The number of subjects who ate breakfast alone was decreased whereas the number of subjects who ate breakfast with friends was increased (p<0.001). There were no significant changes in dietary intakes, mental health status and quality of life. North Korean young adult defectors' willingness to participate and interests in the health promotion program were high, however the practice rate was low. Conclusion: The health promotion program could induce interests and willingness to participate, but bring about limited effects on the health behaviors. These results imply that a health promotion program for North Korean young adult defectors should have a long-term strategy as well as short-term plan. Furthermore, it should be based on their health problems, health related behaviors, academic performance and daily life matters.

• Mycobiology
• /
• 제40권1호
• /
• pp.27-34
• /
• 2012

Fifty three fungi isolated from soils of different microhabitats of eastern Himalayan range (3,400-3,600 msl) were screened for mycosynthesis of silver nanaoparticles (AgNPs) and their efficacy as antimicrobials were assessed in combination with commonly used antibiotics. Three isolates $Aspergillus$ $terreus$ SP5, $Paecilomyces$ $lilacinus$ SF1 and $Fusarium$ sp. MP5 identified based on morphological and 18S rRNA gene sequences were found to synthesize AgNPs. These nanoparticles were characterized by visual observation followed by UV-visible spectrophotometric analysis. The AgNPs synthesized by $Aspergillus$ $terreus$ SP5, $Paecilomyces$ $lilacinus$ SF1 and $Fusarium$ sp. MP5 showed absorbance maxima at 412, 419, and 421 nm respectively in the visible region. Transmission electron microscopy micrograph showed formation of spherical AgNPs of 5-50 nm size. The antimicrobial activity of the mycosynthesized nanoparticles were investigated alone and in combination with commonly used antibiotics for analysis of growth inhibition zone against test organisms, namely, $Staphylococcus$ $aureus$ MTCC96, $Streptococcus$ $pyogenes$ MTCC1925, $Salmonella$ $enterica$ MTCC735 and $Enterococcus$ $faecalis$ MTCC2729. The mycosynthesized nanoparticles showed potent antibacterial activity and interestingly their syngergistic effect with erythromycin, methicillin, chloramphenicol and ciprofloxacin was significantly higher as compared to inhibitions by AgNPs alone. The present study indicates that silver nanoparticles synthesized using soil borne indigenous fungus of high altitudes show considerable antimicrobial activity, deserving further investigation for potential applications.

• 천문학회보
• /
• 제40권1호
• /
• pp.72.3-72.3
• /
• 2015

We present the mid-infrared (MIR) luminosity function (LF) of local (z < 0.3) star forming (SF) galaxies based on the AKARI's NEP-Wide Survey data. We utilized a combination of the NEP-Wide point source catalogue containing a large number (114,000) of infrared (IR) sources distributed over the wide (5.4 sq. deg) field and spectroscopic redshift (z) data for 1790 selected targets obtained by optical follow-up surveys with MMT/Hectospec and WIYN/Hydra. The AKARI's continuous $2{\sim}24{\mu}m$ wavelength coverage and the spectroscopic redshifts for sample galaxies enable us to derive accurate spectral energy distributions (SEDs) in the mid-infrared. We carried out SED-fit analysis and employed 1/Vmax method to derive the mid-IR (e.g., $8{\mu}m$, $12{\mu}m$, and $15{\mu}m$ rest-frame) luminosity functions. Our results for local galaxies from the NEP region generally consistent with various previous works for other fields over wide luminosity ranges. The comparison with the results of the NEP-Deep data implies the luminosity evolution from higher redshifts towards the present epoch. We attempted to fit our derived LFs to the double power-laws and present the resulting power indices. We also examined the correlation between mid-IR luminosity and total IR luminosity.

• 천문학논총
• /
• 제32권1호
• /
• pp.263-265
• /
• 2017

We present the mid-infrared (MIR) luminosity function (LF) of local (z < 0.3) star-forming (SF) galaxies in the North Ecliptic Pole (NEP) field. This work is based on the NEP-Wide point source catalogue and the spectroscopic redshift (z) data for ~ 1700 galaxies obtained by the optical follow-up survey with MMT/Hectospec and WIYN/Hydra. The AKARI's continuous $2-24{\mu}m$ coverage and the spectroscopic redshifts enable us to determine the spectral energy distribution (SED) in the mid-infrared and derive the luminosity functions of galaxies. Our $8{\mu}m$ LF finds good agreements with the results from SWIRE field over the wide luminosity range, while showing significant difference from the NOAO deep data in the faint end. The comparison with higher-z sample shows significant luminosity evolution from z > 0.3 to local universe. $12{\mu}m$ LF also shows a clear indication of luminosity evolution.

• 한국실내디자인학회논문집
• /
• 제18권3호
• /
• pp.102-113
• /
• 2009

The SARS virus began to appear and spread in North America and Southeast Asia in the early 2000' s, infecting and harming many people. In the process of examining the causes for the virus, studies on the airborne SARS virus and the way it spread were carried out mainly in the medical field. In the field of architecture, studies were done on the diffusion of air pollutants in buildings using gases such as $CO_2$, $N_2O$, or $SF_6$, but research on virus diffusion was limited. There were also explanations of only the diffusion process without accurate information and discussion on virus characteristics. The aim of this study is to analyze the physical characteristics of airborne virus, consider the possibility of using coupled analysis model and tracer gas for analyzing virus diffusion in building space and, based on reports of how the infection spread in a hospital where SARS patients were discovered, analyze infection risk using tracer gas density and also diffusion patterns according to the location, shape, and volume of supply diffusers and exhaust grilles. This paper can provide standards and logical principles for evaluating various alternatives for making decisions on vertical or horizontal ward placement, air supply and exhaust installation and air volumes in medium or high story medical facilities.