• Proceedings of the Korean Society of Applied Pharmacology
• /
• 1996.04a
• /
• pp.276-276
• /
• 1996

합성한 BR-8702-2의 시험결과 원소분석에서는 이론치와 실험치가 잘 일치하였고, 구조확인을 위한 FT-IR 및 FT-NMR(H$^1$)등의 시험에서도 구조와 일치하는 결과치를 나타내었다. 합성물질의 정량법을 HPLC 및 구성원소인 P와 N을 이용한 정량법에서도 유의성있는 결과를 얻을 수 있었다. 또한 분말상태인 이 물질의 안정성은 고온 고습하에서도 양호하였으며, 각종 완충수용액에서 pH가 분해에 미치는 영향을 pH-rate profile로 나타낸 결과 pH7, 8, 9에서 안정하였고 pH8에서 k=1.3$\times$$10^{-4}$day으로 가장 안정하여 shelf life는 807일이었다. 광에 대해서도 k=5.8$\times$$10^{-4}$day로 매우 안정하였다.

• Clinical and Experimental Pediatrics
• /
• v.63 no.4
• /
• pp.119-124
• /
• 2020

A cluster of severe pneumonia of unknown etiology in Wuhan City, Hubei province in China emerged in December 2019. A novel coronavirus named severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) was isolated from lower respiratory tract sample as the causative agent. The current outbreak of infections with SARS-CoV-2 is termed Coronavirus Disease 2019 (COVID-19) by the World Health Organization (WHO). COVID-19 rapidly spread into at least 114 countries and killed more than 4,000 people by March 11 2020. WHO officially declared COVID-19 a pandemic on March 11, 2020. There have been 2 novel coronavirus outbreaks in the past 2 decades. The outbreak of severe acute respiratory syndrome (SARS) in 2002-2003 caused by SARS-CoV had a case fatality rate of around 10% (8,098 confirmed cases and 774 deaths), while Middle East respiratory syndrome (MERS) caused by MERS-CoV killed 861 people out of a total 2,502 confirmed cases between 2012 and 2019. The purpose of this review is to summarize known-to-date information about SARS-CoV-2, transmission of SARS-CoV-2, and clinical features.

• Journal of the Korean Ceramic Society
• /
• v.13 no.4
• /
• pp.5-8
• /
• 1976

Both oriented and non-oriented ferroxplana $Co_{1-x}Zn_xZ(Ba_3Co_{2(1-x)}Zn_{2x} Fe_{24}O_{41})$ with x=0.00, 0.45 were prepared by conventional ceramic method. The magnetostrictions of thus prepared specimens were measured by use of the three terminal capacitor device at room temperature. The magnitude of measured values was approximately five times greater than that of ZnY ferroxplana. The easy-magnetization plane at room temperature of both CoZ and Co0.55 $Zn_{0.45}$Z was their basal plane. The magentostrictions in the basal plane and the other planes showed saturated values at magnetic field intensity of about 2Koe and 4Koe, respectively. The magnetostriction constants $K_1, \; K_2, \;K_3\; and\; K_4$ for CoZ were -2.4, -10.5, -5.9 and -45.2$\times10^{-6}$ , while those for $Co_{0.55}Zn_{0.45}Z$ were +0.1, -1.2, -6.3 and -39.0$\times$10^{-6}, , respectively.

• Clean Technology
• /
• v.21 no.1
• /
• pp.68-75
• /
• 2015

In this study, we investigated the structure and properties of a highly heat conductive metal-ceramic core-shell CoAl₂O₄@Al micro-composite for heterogeneous catalysts support. The CoAl₂O₄@Al was prepared by hydrothermal surface oxidation of Al metal powder, which resulted in the structure with a high heat conductive Al metal core encapsulated by a high surface area CoAl₂O₄ shell. For comparison, CoAl₂O₄ was also prepared by co-precipitation method and also utilized for a catalyst support. Rh catalysts supported on CoAl₂O₄@Al and CoAl₂O₄ were prepared by incipient wetness impregnation and characterized by N₂ adsorption, X-ray diffraction (XRD), scanning electron microscopy (SEM), CO chemisorption, and temperature-programmed reduction (TPR). The properties of catalysts were investigated for glycerol steam reforming reaction for hydrogen production at 550 ℃. Rh/CoAl₂O₄@Al exhibited about 2.8 times higher glycerol conversion turnover frequency (TOF) than Rh/CoAl₂O₄ due to facilitated heat transport through the core-shell structure. The CoAl₂O₄@Al and CoAl₂O₄ also showed some catalytic activities due to a partial reduction of Co on the support, and a higher catalytic activity was also found on the CoAl₂O₄@Al core-shell than CoAl₂O₄. These catalysts, however, displayed deactivation on the reaction stream due to carbon deposition on the catalysts surface.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.28 no.8 s.227
• /
• pp.937-944
• /
• 2004

An experimental study has been conducted to evaluate the effects of $CO_2$ on heat transfer from oxygen-enriched hydrogen flame. Experiments were performed on flames stabilized by a co-flow swirl burner, which was mounted on top of the furnace. Five different oxidizer compositions were prepared by replacing $N_2$ with $CO_2$. In a steady state, the total as well as radiative heat flux from the flame to the wall of furnace have been measured using a heat flux meter. Temperature distribution in furnace also has been measured and compared. By increasing $CO_2$ proportion in the oxidizer, the convection played a more significant role rather than radiation. Overall temperature in the furnace was seen to be decreased, while the total heat flux has increased.

• Journal of Environmental Science International
• /
• v.11 no.8
• /
• pp.773-781
• /
• 2002

The natural carbon cycle has been perturbed since the mid-19th century by anthropogenic CO$_2$emissions from fossil fuel combustion and deforestation due to population growth and industrialization. The current study simulated the global carbon cycle for the past 42 years using an eight-box carbon cycle model. The results showed that since the terrestrial biospheric carbon sink was roughly offset by the deforestation source, the fossil fuel emission source was partitioned between the atmospheric and oceanic sinks. However, the partitioning ratio between the atmosphere and the ocean exhibited a change, that is, the carbon accumulation rate was faster in the atmosphere than in the ocean, due to a decrease in the so-called ocean buffering capacity. It was found that the ocean buffering capacity to take up excess CO$_2$decreased by 50% in terms of the buffer factor over the past 42 years. Accordingly, these results indicate that if the current CO$_2$emission trend continues, the future rate of increase in the atmospheric CO$_2$concentration will accelerate.

• The Korean Journal of Physiology
• /
• v.1 no.2
• /
• pp.185-191
• /
• 1967

In order to evaluate the elimination of CO through the lung comparing with the decrease of CO content in the blood, authors had induced acute CO poisoning on 9 dogs. Arterial CO-Hb saturation, CO concentration, %, in expired gas and eliminated CO amount through the lung were measured at 1,5,10,30,60, and 120 minutes after acute CO poisoning in 6 dogs breathing room air and 3 dogs breathing room air and oxygen alternately. Results obtained are summarized as follows. In room air breathing group, arterial CO-Hb saturation averaged 50.8% , and 53.67 ml of CO was blew off through the lung during 120 minutes and in alternately air and oBygen breathing group, the arterial CO-Hb saturation averaged 65.6% and 95.6 ml of CO was blew off through the lung. The amount of CO eliminated in expired gas for 120 minute was much less than the amount of decreased CO in arterial blood which was calculated with the decreased CO-Hb content in the estimated circulating blood volume. Such difference between the amount of eliminated CO in expired gas and the decreased CO in blood might be attributed to the oxidation of CO to $CO_2$ in the tissues. Concentration of CO in expired gas was markedly increased and the rate of decrease in arterial CO-Hb saturation is enhanced by oxygen breathing. In early period of recovery from acute CO poisoning, neither the CO concentration in expired gas, nor, the rate of CO elimination (unlit 2 minutes after CO poisoning) showed close correlation with the blood CO-Hb saturation level. The reason seemed to be due to irregularly depressed or unevenly stimulated respiration which were induced by acute CO poisoning.

• Korean Journal of Crystallography
• /
• v.6 no.2
• /
• pp.125-133
• /
• 1995

The crystal structure of dehydrated, partially Co(II)-exchanged zeolite X, stoichiometry Co2+Na+-X (Co41+Na10Si100Al92O384) per unit cell, has been determined from three-dimensional X-ray diffraction data gathered by counter methods. The structure was solved and refined in the cubic space group Fd3:α=24.544(1)Å at 21(1)℃. The crystal was prepared by ion exchange in a flowing stream using a solution 0.025 M each in Co(NO3)2 and Co(O2CCH3)2. The crystal was then dehydrated at 380℃ and 2×10-6 Torr for two days. The structure was refined to the final error indices, R1=0.059 and R2=0.046 with 211 reflections for which I > 3σ(I). Co2+ ions and Na+ ions are located at the four different crystallographic sites. Co2+ ions are located at two different sites of high occupancies. Sixteen Co2+ ions are located at the center of the double six-ring (site I; Co-O = 2.21(1)Å, O-Co-O = 90.0(4)°) and twenty-five Co2+ ions are located at site II in the supercage. Twenty-five Co2+ ions are recessed 0.09Å into the supercage from its three oxygen plane (Co-O = 2.05(1)Å, O-Co-O = 119.8(7)°). Na+ ions are located at two different sites of occupandies. Seven Na+ ions are located at site II in the supercage (Na-O = 2.29(1)Å, O-Na-O = 102(1)°). Three Na+ ions are statistically distribyted over site III, a 48-fold equipoint in the supercages on twofold axes (Na-O = 2.59(10)Å, O-Na-O = 69.0(3)°). Seven Na+ ions are recessed 1.02Å into the supercage from the three oxygen plane. It appears that Co2+ ions prefer sites I and II in order, and that Na+ ions occupy the remaining sites, II and III.

• Journal of Korean Society of Environmental Engineers
• /
• v.35 no.8
• /
• pp.547-553
• /
• 2013

This paper investigates the effect of coal-fired fly ash on dry $CO_2$ sorbents as the supports and additives. For this purpose, various kinds of dry sorbent were manufactured by mixing fly-ash, the primary $CO_2$ absorption components (NaOH and CaO) and water with their different combination. Thereafter, their $CO_2$ absorption performance and the property were analyzed. As a result, variation of absorption efficiency and temperature as well as $CO_2$ desorption of the sorbents are confirmed, which may be primarily ascribed to fly-ash addition to the sorbents. Particularly, fly-ash effect is strongly measured in the sorbent manufactured by mixing all four components (named WNCF sorbents). Absorption efficiency of WNCF sorbents at $550^{\circ}C$ is 35.6% higher than that of flyash free sorbent and desorption is solely observed in WNCF sorbents. Fly-ash in WNCF sorbents leads to increase the dispersity of $CO_2$ absorption components and decrease their particle size in the sorbents. In addition, fly-ash is used as the supports and pozzolanic reaction is hindered by NaOH in WNCF sorbent. Furthermore, $CO_2$ desorption from the sorbents may be due to fly-ash. The interaction between fly-ash and $CO_2$ absorption components substantially attenuate the strength between captured $CO_2$ in CaO and NaOH.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.22 no.8
• /
• pp.545-552
• /
• 2010

Research and development efforts to reduce $CO_2$ emission are in progress to cope with global warming. $CO_2$ emission from fossil fuel fired power plants is a major greenhouse gas source and the post-combustion $CO_2$ capture is considered as a short or medium term option to reduce $CO_2$ emissions. In this study, the application of the post-combustion $CO_2$ capture system, which is based on chemical absorption and stripping processes, to typical fossil fuel fired power plants was investigated. A coal fired plant and a natural gas fired combined cycle plant were selected. Performance of the MEA-based $CO_2$ capture system combined with power plants was analyzed and overall plant performance including the energy consumption of the $CO_2$ capture process was investigated.