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        검색결과 25

        1.
        2021.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Abstract Activated carbon from the shell of the cashew of Para (SCP) was produced by chemical activation with ZnCl using the ratio of SCP: ZnCl2 1.0:1.5 at 700 °C. The prepared activated carbon (SCP700) was used for the removal of two emerging contaminants, 4-bromophenol (4-BrPhOH) and 4-chloroaniline (4-ClPhNH2) that are primarily employed in the industry. Different analytical techniques were used to characterize the activated carbon. From the N2 adsorption–desorption isotherms were obtained the specific surface area of 1520 m2 g− 1 and total pore volume of 0.492 cm3 g−1. The functional groups were identified by the FTIR technique and quantified by modified Boehm titration. The results revealed the bearing of several functional groups on the SCP700 surface, which may utterly influence the removal of the emerging contaminants. The equilibrium experiments showed that the maximum uptaken capacities (Qmax) achieved at 45 °C were 488.2 (4-BrPhOH) and 552.5 mg g−1 (4-ClPhNH2). The thermodynamic parameters demonstrated that the processes of 4-BrPhOH and 4-ClPhNH2 adsorption are exothermic, spontaneous, energetically suitable, and the magnitude of ΔH° is compatible with physisorption. The mechanism of the adsorption of the emerging contaminants onto the carbon surface is dominated by microporous filling, hydrogen bonds, π-stacking interactions, and other Van der Waals interactions. The use of activated carbon for the treatment of industrial synthetic wastewater with several inorganic and organic molecules commonly found in industrial effluents showed a very high percentage of uptaking (up to 98.64%).
        4,900원
        2.
        2018.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present the analysis of KMT-2016-BLG-0212, a low flux-variation (Iflux−var ∼ 20 mag) microlensing event, which is in a high-cadence (Γ = 4hr −1) field of the three-telescope Korea Microlensing Telescope Network (KMTNet) survey. The event shows a short anomaly that is incompletely covered due to the brief visibility intervals that characterize the early microlensing season when the anomaly occurred. We show that the data are consistent with two classes of solutions, characterized respectively by low-mass brown-dwarf (q = 0.037) and sub-Neptune (q < 10−4) companions. Future high-resolution imaging should easily distinguish between these solutions.
        4,000원
        4.
        2016.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the characterization of a massive (mp = 3:91:4Mjup) microlensing planet (OGLE- 2015-BLG-0954Lb) orbiting an M dwarf host (M = 0:33  0:12M ) at a distance toward the Galactic bulge of 0:6+0:4 􀀀0:2 kpc, which is extremely nearby by microlensing standards. The planet-host projected separation is a?  1:2AU. The characterization was made possible by the wide- eld (4 deg2) high cadence (􀀀 = 6 hr􀀀1) monitoring of the Korea Microlensing Telescope Network (KMTNet), which had two of its three telescopes in commissioning operations at the time of the planetary anomaly. The source crossing time t = 16 min is among the shortest ever published. The high-cadence, wide- eld observations that are the hallmark of KMTNet are the only way to routinely capture such short crossings. High-cadence resolution of short caustic crossings will preferentially lead to mass and distance measurements for the lens. This is because the short crossing time typically implies a nearby lens, which enables the measurement of additional e ects (bright lens and/or microlens parallax). When combined with the measured crossing time, these e ects can yield planet/host masses and distance.
        4,000원
        5.
        2015.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Polarbear is a ground-based experiment located in the Atacama desert of northern Chile. The experiment is designed to measure the Cosmic Microwave Background B-mode polarization at several arcminute resolution. The CMB B-mode polarization on degree angular scales is a unique signature of primordial gravitational waves from cosmic in ation and B-mode signal on sub-degree scales is induced by the gravitational lensing from large-scale structure. Science observations began in early 2012 with an array of 1,274 polarization sensitive antenna-couple Transition Edge Sensor (TES) bolometers at 150 GHz. We published the first CMB-only measurement of the B-mode polarization on sub-degree scales induced by gravitational lensing in December 2013 followed by the first measurement of the B-mode power spectrum on those scales in March 2014. In this proceedings, we review the physics of CMB B-modes and then describe the Polarbear experiment, observations, and recent results.
        3,000원
        7.
        2009.05 구독 인증기관·개인회원 무료
        Predation, development, and ovipostion experiments were conducted to evaluate Amblyseius swirskii (Athias-Henriot) (Acari: Phytoseiidae) as a potential biological control agent for tomato russet mite, Aculops lycopersici (Massee) (Acari: Eriophyidae) which is a periodic pest of greenhouse tomatoes. Results show that A. swirskii attacked all developmental stages of A. lycopersici, and had a type II functional response on the prey densities given. The predation rates of A. swirskii on A. lycopersici in the presense of alternative food sources such as pollen, thrips first instar, or whitefly eggs were recorded as 74%, 56%, and 76%, respectively of the predation rate on A. lycopersici alone. Amblyseius swirskii successfully completed their life-cycle on either A. lycopersici or cattail pollen. At 25oC, 70% RH, development time of female A. swirskii fed on A. lycopersici or on cattail pollen took 5.0 and 6.2 days, respectively. For the first 10 days after moulting to the adult stage, A. swirskii fed on A. lycopersici had higher daily oviposition rate (2.0 eggs per day) than on pollen (1.5 eggs per day). From this laboratory study, it can be concluded that A. swirskii has promising traits as a predator against A. lycopersici and that their populations can be stably maintained using alternative food such as cattail pollen. We suggest that the effectiveness of A. swirskii against A. lycopersici under field conditions deserves to be investigated.
        10.
        2006.09 구독 인증기관·개인회원 무료
        Solid Oxide Fuel Cell technology uses powder processes to produce electrodes with residual porosity by partially sintering a mixture of electronically and ionically conducting particles. We model porous fuel cell electrodes with 3D packings of monosized spherical particles. These packings are created by numerical sintering. Each particle-particle contact is characteristic for an ionic, electronic or electrochemical resistance. The numerical packing is then discretized into a resistor network which is solved by using Kirchhoff's current law to evaluate the electrode's electrochemical performance. We investigate in particular percolation effects in functionally graded electrodes as compared to other types of electrodes.
        11.
        2006.04 구독 인증기관·개인회원 무료
        The free sintering of metallic powders blended with non sintering inclusions is investigated by the Discrete Element Method (DEM). Each particle, whatever its nature (metallic or inclusion) is modeled as a sphere that interacts with its neighbors. We investigate the retarding effect of the inclusions on the sintering kinetics. Also, we present a simple coarsening model for the metallic particles, which allows large particles to grow at the expense of the smallest.
        15.
        2004.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We present photometric results for four new variable stars discovered in the vicinity of the ZZ Ceti-type pulsating white dwarf BR Cam. Observations were performed on 5 nights in November 2003 using the 1.8m telescope at Bohyunsan Optical Astronomy Observatory with no filter, on 3 nights in December 2003 using the 0.61m telescope at Sobaeksan Optical Astronomy Observatory with V, I filters, and on 3 nights in October 2004 using the 1.0m telescope at Mt. Lemmon Optical Astronomy Observatory with V, I filters. We estimated their periods from the phase-match technique for one eclipsing binary and the multiple frequency analysis for three pulsating stars. By considering the light curve shape, period and amplitude difference between two passbands, we classified the objects by their variability types as follows: V1 (USNO-A2.0 1425-05691757) is a W UMa-type eclipsing binary with an orbital period of 0d.4641; V2 (USNO-A2.0 1425-05703335) is a multi-periodic δ Sct-type pulsating star with a dominant period of 0d.0649; V3 (USNO-A2.0 1425-05699659) is also a δ Sct-type pulsating star with a period of 0d.1408; and V4 (USNO-A2.0 1425-05707705) is a RR Lyr-type pulsating star with a period of 0d.2643.
        4,000원
        16.
        1996.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        An x-ray astronomy experiment consisting of three collimated proportional counters and an X-ray Sky Monitor (XSM) was flown aboard the Indian Satellite IRS-P3 launched on March 21, 1996 from SHAR range in India. The Satellite is in a circular orbit of 830 km altitude with an orbital inclination of 98° and has three axis stabilized pointing capability. Each pointed-mode Proportional Counter (PPC) is a multilayer, multianode unit filled with P-10 gas (90% Ar + 10% CH4) at 800 torr and having an aluminized mylar window of 25 micron thickness. The three PPCs are identical and have a field of view of 2°×2° defined by silver coated aluminium honeycomb collimators. The total effective area of the three PPCs is about 1200 cm2. The PPCs are sensitive in 2-20 keV band. The XSM consists of a pin-hole of 1 cm2 area placed 16 cm above the anode plane of a 32 cm×32 cm position sensitive proportional counter sensitive in 3-8 keV interval. The position of the x-ray events is determined by charge division technique using nichrome wires as anodes. The principal objective of this experiment is to carry out timing studies of x-ray pulsars, x-ray binaries and other rapidly varying x-ray sources. The XSM will be used to detect transient x-ray sources and monitor intensity of bright x-ray binaries. Observations of black-hole binary Cyg X-1 and few other binary sources were carried out in early May and July-August 1996 period. Details of the x-ray detector characteristics are presented and preliminary results from the observations are discussed.
        3,000원
        20.
        1992.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A laboratory bioassay that incorporates Bacillus thuringiensis (Bt) purified crystal protein toxins into an artificial diet has identified three toxins, CryIA(b), CryIA(c), and CryIIA, to by effective against the yellow stemborer, Scirpophaga incertulas(Walker). Research is aimed at engineering rice that incorporates genes of one of or more of these toxins so as to mimic the insecticidal action of the insect to Bt. The paper discusses potential strategies for slowing the rate of adaptation that include the use of multiple Bt toxins, promoters that express the toxins only in specific plant tissues at specific times, and mixing transgenic and non-transgenic plants.
        4,000원
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