• Journal of the Korean Magnetics Society
• /
• v.20 no.5
• /
• pp.187-190
• /
• 2010

$Sn_{0.99}{^{57}Fe}_{0.01}O_2$ prepared by a sol-gel method, and studied by x-ray diffractometer, vibrating magnetometer, Superconducting quantum interference devices and M$\ddot{o}$ssbauer spectroscopy. the crystal structure were found to be a rutile tetragonal structure with space group $P4_2$/mnm, and oxygen deficiency are 5.6 % by Rietveld refinement. magnetization value were $M_s=1.95{\times}10^{-2}{\mu}_B/Fe$ at room temperature, and Curri-weiss temperature were and ${\theta}_{cw}$ = 18 k, measurement of VSM and SQUID, respectively. Mssbauer spectra of $Sn_{0.99}{^{57}Fe}_{0.01}O_2$ have been Sextet taken at various temperatures ranging from 4.2 K to RT, and isomer shift value $\delta$ = 0.18~0.36 mm/s of $^{57}Fe$ ion site all of the temperature range the state shows ferric.

• Applied Chemistry for Engineering
• /
• v.32 no.6
• /
• pp.632-639
• /
• 2021

In this research, fluorine doping was performed to enhance the photocatalytic activities of WO₃ which were measured using methylene blue dye. WO_3-xF_x photocatalyts were prepared by a vaper phase fluorination during a sintering for preparing WO₃ photocatalysts from a WCl₆ precursor. The bandgap energy of WO₃ photocatalysts decreased from 2.95 eV to 2.54 eV, and the oxygen vacancies site increased by about 55% after fluorine doping. In addition, the initial degradation efficiency of methylene blue showed that the fluorine doped sample showed a 6-fold increase in photocatalytic activities from 10% to 60% compared to that of the untreated sample. It is believed that fluorine is doped to reduce the band gap of photocatalysts, enabling the catalytic activity with low energy, and that oxygen vacancies-generated surface defects increase the visible light absorption region of WO₃ photocatalysts, thereby increasing photocatalytic activity. In this study, it was confirmed that fluorine-doped WO_3-xF_x photocatalysts with an excellent photocatalytic activity can be manufactured easily using a one-step vaper phase fluorination that does not require a post-treatment process.

• Ocean and Polar Research
• /
• v.28 no.4
• /
• pp.407-413
• /
• 2006

The effect of water temperature and photoperiod on the oxygen consumption of the fasted juvenile parrot fish, Oplegnathus fasciatus was investigated to provide empirical data for the early-stage culture management and bioenergetic growth model of the species. The mean body weight of the juvenile used for the experiment was $21.5{\pm}1.9g$, and the oxygen consumption rate was measured under four water temperatures (10, 15, 20 and $25^{\circ}C$) and three photoperiods (24L:0D, 12L:12D and OL:24D) with an interval of 5 minutes for 24 hours using a continuous flow-through respirometer. In each treatment three replicates were set up and 15 juveniles were totally involved. The oxygen consumption rates increased with increasing water temperature under all photoperiod treatments (P<0.001). Mean oxygen consumption rates at 10, 15, 20 and $25^{\circ}C$ ranged $202.1{\sim}403.4,\;306.7{\sim}502.2,\;536.7{\sim}791.0\;and\;879.9{\sim}1,077.4mg\;O_2\;kg^{-1}h^{-1}$, respectively. $Q_{10}$ values ranged $1.58{\sim}2.30$ between 10 and $15^{\circ}C,\;2.44{\sim}3.06$ between 15 and $20^{\circ}C\;and\;1.86{\sim}2.6y9$ between 20 and $25^{\circ}C$, respectively. Mean oxygen consumption rates of O. fasciatus were the highest in continuous light (24L:0D) followed by 12L:12D and 0L:24D (P<0.001). The oxygen consumption of fish exposed to the 12L:12D photoperiod was significantly higher during the light phase than during the dark phase under all temperature treatments (P<0.001). In summary, oxygen consumption rates of the juvenile parrot fish increase with increasing water temperature and lengthening daylight period; and, thereby, changes in water quality resulted from the depletion of oxygen under high temperature and long daylight photoperiod conditions should be monitored.

• Clinical and Experimental Pediatrics
• /
• v.49 no.4
• /
• pp.455-459
• /
• 2006

The major pathogenesis of acute respiratory distress syndrome (ARDS) is an inflammatory process that results from a diversity of injuries to the body. Due to the various cytokines and vasoactive peptides released from the endothelium, the vascular permeability is increased; the migration of inflammatory cells and the leakage of plasma proteins then occur and edema develops in the alveolus. There is a hypothesis that the impairment of alveolar recruitment in ARDS is caused by a defect of the surfactant system and the resultant increase of alveolar surface tension. This has been studied in pediatric patients in ARDS; after the administration of surfactant, hypoxia, respiratory symptoms and survival chances were improved. To alleviate the major pathogenic mechanism in this disease, that is to say, inflammation of the lung, steroids have been used and studied as another treatment modality for ARDS, and it has been concluded that the administration of low dose methylprednisolone may improve patients' symptoms and survival rates. We report here on a case of a young infant admitted with ARDS, who, after the intratracheal administration of 120 mg/kg surfactant, on $PaO_2/FiO_2$ was elevated. Subsequent low doses of methylprednisolone were given, and the symptoms did not recur, and no fibrotic change was shown during the follow-up period of 2 months.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.40 no.1
• /
• pp.31-37
• /
• 2016

Co-firing of biomass with coal is a promising combustion technology in a coal-fired power plant. However, it still requires verifications to apply co-firing in an actual boiler. In this study, data from the Thermogravimetric analyzer(TGA) and Drop tube furnace(DTF) were used to obtain the combustion characteristics of biomass when co-firing with coal. The combustion characteristics were verified using experimental results including reactivity from the TGA and Unburned carbon(UBC) data from the DTF. The experiment also analyzed with the variation of the biomass blending ratio and biomass particle size. It was determined that increasing the biomass blending ratio resulted in incomplete chemical reactions due to insufficient oxygen levels because of the rapid initial combustion characteristics of the biomass. Thus, the optimum blending condition of the biomass based on the results of this study was found to be 5 while oxygen enrichment reduced the increase of UBC that occurred during combustion of blended biomass and coal.

• KSBB Journal
• /
• v.13 no.6
• /
• pp.681-686
• /
• 1998

Effect of glucose feeding strategy and initial concentration of glucose on Serratia marcescens ATCC 27117 in high cell density fed-batch fermentation was investigated. The final biomasses in batch, constant feeding, constant and exponentially feeding strategy at glucose starvation condition in fed-batch were 1.40, 5,07, 6,93 and 7.60 g/L at 40, 41, 24 and 40 hrs, respectively. Productivities of biomass were 0.035, 0.124, 0.289 and 0.190 g/L$.$h, respectively. As a result, constant feeding strategy at starvation condition was 1.5∼8.6 times higher than other strategies. The relationship between dissolved oxygen and glucose feeding times was good identified in exponential feeding strategy and constant feeding strategy at starvation condition. And high cell density cultivation was obtained when minimal media was used.

• KSBB Journal
• /
• v.11 no.2
• /
• pp.201-210
• /
• 1996

The production of polyhydroxyalkanoate(PHA) from glucose by batch and fed-batch culture of Pseudomonas sp. HJ was studied. In batch culture using fermentor, 400 rpm of agitalion speed, 2 vvm of aeration rate, 18 hours of inoculum age, and 5% (vlv) of inoculum size were optimal. PHA production was not increased by deficiency of oxygen. In a batch culture, the final call mass was $6.251g/\ell$, and PHA content was 20% of dry cell weight. In a constant feeding fed-batch culture, cell mass increased to $33.24g/\ell$, and PHA content reached 48.9% of dry cell weight. In an intermittent feeding fed-batch culture, cell mass increased to $37.89g/\ell$, and PHA content reached 53.5% of dty cell weight.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2005.05b
• /
• pp.102-105
• /
• 2005

가스센서는 응용 분야와 기능 및 종류가 다양하고 최첨단 분야로서 학문적으로는 물리, 화학, 전기, 전자 및 기계 등의 배경을 필요로 하며 산업적으로는 공업 전 분야와 농림, 축산, 사무기기에서 뿐만 아니라 공해 방진용(자동차 연소제어 및 배출가스 제어, 대기오염 감시등), 민생용(조리, 환기, 공조 등), 교통 보안용(음주운전측정 및 음주운전 방지장치 등), 방재용(가스 누설 탐지기, 불완전 연소 방지, 산소 결핍, 화재 등), 의료용(호기, 마취가스의 분석 등) 매우 광범위하며 점점 더 확대되어 가고 있다. 본 연구에서는 검출 가스 종류에 따라 졸-겔법으로 감응막을 최적 설계하고, 최적으로 설계된 감응막을 디핑법으로 코팅처리한 후 최적으로 열처리하여 센서를 제작하였다. 또한, 자체 제작한 가스검출 시스템에 제작된 센서를 장착하여 센서의 가스 검출 특성을 측정하고, 측정 데이터를 이용하여 휴대용 가스 검출 시스템을 설계 제작하였다.

• Maxillofacial Plastic and Reconstructive Surgery
• /
• v.13 no.1
• /
• pp.110-116
• /
• 1991

Fracture site osteomyelitis begins rarely with an acute event but rather has a subacute onset. It develops almost exclusively in the mandibular region. The treatment principles of mandibular fracture site osteomyelitis are complete removal of inflammatory tissue and drainage, rigid fixation with or without autogenous bone bone graft and specific antibiotic therapy. But hyperbaric oxygen used as a modality in the treatment of intractable osteomyelitis. In this paper, we reported that the three patients who have osteomyelitis accompying secondary in fection after mandibular fracture.

• Microbiology and Biotechnology Letters
• /
• v.32 no.2
• /
• pp.149-153
• /
• 2004

L-Threonine fermentation process was constructed on batch and fed-batch culture by using Escherichia coli MT201. The production type of L-threonine was observed as growth-associated production in batch culture. In fed-batch culture studying optimal concentration of yeast extract in feeding media, when 600 g/l of glucose and 60 g/l of yeast extract were added in feeding media, 87 g/$\ell$ of L-threonine was produced. To improve cell growth and L-threonine production, the culture of high cell density was performed in fed-batch culture with oxygen enriched air and feeding media containing L-methionine and phosphate. Under the conditions, we could achieve the highest L-threonine production of98 g/$\ell$ at 60 h. The highest productivity of L-threonine was about 3.85 g/$\ell$/h.