• Title/Summary/Keyword: active flux

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The Effect of Enhancer on the Penetration of Indapamide through Hairless Mouse Skin (경피흡수촉진제의 영향에 따른 인다파마이드의 피부투과)

  • Seo, Hui;Jeung, Sang-Young;Park, Ji-Seon;Shin, Byung-Cheol;Hwang, Sung-Joo;Cho, Sun-Hang
    • Journal of Pharmaceutical Investigation
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    • v.37 no.4
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    • pp.237-242
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    • 2007
  • The chemical formula of indapamide is 3-(aminosulfonyl)-4-chloro-N-(2,3-dihydro-2-methyl-1H-indol-l-yl)-benzamide, Indapamide is an oral antipertensive diuretic agent indicated for the treatment of hypertensive and edema. Indapamide inhibits carbonic anhydrase enzyme. Transdermal drug delivery systems, as compared to their corresponding classical oral or injectable dosage form counterparts, offer many advantages. The most important advantages are improved systemic bioavailability of the pharmaceutical active ingredients (PAI), because the first-pass metabolism by the liver and digestive system are avoided; and the controlled, constant drug delivery profile (that is, controlled zero-order absorption). Also of importance is the reduced dose frequency compared to the conventional oral dosage forms (that is, once-a-day, twice-a-week or once-a-week). Other benefits include longer duration of therapeutic action from a single application, and reversible action. For example, patches can be removed to reverse any adverse effects that may be caused by overdosing. In order to evaluate the effects of vehicles and penetration enhancers on skin permeation of Indapamide, the skin permeation rates of Indapamide from vehicles of different composition were determined using Franz cells fitted with excised hairless skins. Solubility of Indapamide in various solvents was investigated to select a vehicle suitable for the percutaneous absorption of Indapamide, The solvents used were Tween80, Tween20, Labrasol, Lauroglycol90 (LG90) and Peceol. Lauroglycol90 increase the permeability of indapamide approximately 3.75-fold compared with the control. Tween80, Tween20, Labrasol, Lauroglycol90 (LG90) and Peceol showed flux of $0.06ug/cm^2/hr,\;0.4ug/cm^2/hr,\;0.21ug/cm^2/hr,\;0.72ug/cm^2/hr,\;0.29ug/cm^2/hr$, respectively.

Development of a Daily Solar Major Flare Occurrence Probability Model Based on Vector Parameters from SDO/HMI

  • Lim, Daye;Moon, Yong-Jae;Park, Jongyeob;Lee, Kangjin;Lee, Jin-Yi
    • The Bulletin of The Korean Astronomical Society
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    • v.42 no.2
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    • pp.59.5-60
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    • 2017
  • We present the relationship between vector magnetic field parameters and solar major flare occurrence rate. Based on this, we are developing a forecast model of major flare (M and X-class) occurrence rate within a day using hourly vector magnetic field data of Space-weather HMI Active Region Patch (SHARP) from May 2010 to April 2017. In order to reduce the projection effect, we use SHARP data whose longitudes are within ${\pm}60$ degrees. We consider six SHARP magnetic parameters (the total unsigned current helicity, the total photospheric magnetic free energy density, the total unsigned vertical current, the absolute value of the net current helicity, the sum of the net current emanating from each polarity, and the total unsigned magnetic flux) with high F-scores as useful predictors of flaring activity from Bobra and Couvidat (2015). We have considered two cases. In case 1, we have divided the data into two sets separated in chronological order. 75% of the data before a given day are used for setting up a flare model and 25% of the data after that day are used for test. In case 2, the data are divided into two sets every year in order to reduce the solar cycle (SC) phase effect. All magnetic parameters are divided into 100 groups to estimate the corresponding flare occurrence rates. The flare identification is determined by using LMSAL flare locations, giving more numbers of flares than the NGDC flare list. Major results are as follows. First, major flare occurrence rates are well correlated with six magnetic parameters. Second, the occurrence rate ranges from 0.001 to 1 for M and X-class flares. Third, the logarithmic values of flaring rates are well approximated by two linear equations with different slopes: steeper one at lower values and lower one at higher values. Fourth, the sum of the net current emanating from each polarity gives the minimum RMS error between observed flare rates and predicted ones. Fifth, the RMS error for case 2, which is taken to reduce SC phase effect, are smaller than those for case 1.

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Seasonal Variations of Sediment Oxygen Demand and Denitrification in Kanghwa Tidal Flat Sediments (강화도 갯벌 퇴적물의 산소요구량과 탈질소화의 계절 변화)

  • An, Soon-Mo
    • The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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    • v.10 no.1
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    • pp.47-55
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    • 2005
  • Seasonal variations of remineralization and inorganic nitrogen removal capacity were measured from Dec. 2001 to Apr. 2004 in a tidal flat located in south-western pan of Gwanghwa island, Korea by measuring the sediment oxygen demand (SOD) and denitrification. SOD was higher in muddy sediment (Dong-Mak; three year average=$683;m^{-2}d^{-1}$) than sandy sediment(Yeocha; three year average=$457;m^{-2}d^{-1}$). The SOD was high in summer and tended to be lower in winter. During the sediment incubation in Apr. 2002, production of oxygen from sediment was observed implying active benthic photosynthesis. Denitrification was also higher in muddy sediment (Dong-Mak: $5.4;m^{-2}d^{-1}$) than sandy sediment (Yeocha; $3.4;m^{-2}d^{-1}$). The denitrification rate corresponds to the carbon remineralization rate of 9.3 and $5.9\;mg-C\;m^{-2}d^{-1}$ in Dong-Mak and Yeocha, respectively. The denitrification rates were lower compared to rates observed in other coastal area $(0{\sim}200\;{\mu}mole\;m^{-2}h^{-1})$. Although Kwanghwa tidal flat sediments are replete in organic matter, remineralization activity seems to be limited by the availability of labile organic matter. The Kwangwha tidal flat may have potential to effectively remove large load of organic matter. Net remineralization rates were 196 and $132\;mg-C\;m^{-2}d^{-1}$ in Dong-Mak and Yeocha, respectively.

Primary Production System in the Southern Waters of the East Sea, Korea I. Biomass and Productivity (한국동해 남부해역의 일차생산계 I. 생물량과 생산력)

  • SHIM, JAE HYUNG;YEO, HWAN GOO;PARK, JONG GYU
    • 한국해양학회지
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    • v.27 no.2
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    • pp.91-100
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    • 1992
  • For the study on the structure and characteristics of the primary production system in the southern waters of the East Sea, chlorophyll, phytoplankton standing stocks. nutrients and hydrographic properties were investigated and analyzed in conjunction with measurement of C-14 based primary productivity. The primary productivity was relatively high in comparison with the previous studies, ranging from 284 to 4,574 mgC$.$m/SUP -2/$.$day /SUP -1/ and averaged to be 2,000 mgC$.$m/SUP 02/$.$day/SUP -1/. The standing stocks within the euphotic zone were fairly high, but ambient inorganic nitrogenous nutrient concentrations were too low to support the high production. This implied that there might be active recycling of nitrogenous nutrients by heterotrophic processes and the upward flux of nutrients by vertical mixing. Subsurface chlorophyll maxima were continuously observed in the lower parts of the euphotic layer and the depth coincided with the nutricline rather than isopycnal surfaces, supporting the view that chlorophyll distributions and primary production were primarily influenced by nutrient supply. Despite low nutrient concentrations, phytoplankton standing stocks and production were fairly high and the fraction of autotrophic nano- and picoplankton production was significant.

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THE MILLIMETER-RADIO EMISSION OF BL LACERTAE DURING TWO γ-RAY OUTBURSTS

  • Kim, Dae-Won;Trippe, Sascha;Lee, Sang-Sung;Park, Jong-Ho;Kim, Jae-Young;Algaba, Juan-Carlos;Hodgson, Jeffrey A.;Kino, Motoki;Zhao, Guang-Yao;Wajima, Kiyoaki;Kang, Sincheol;Oh, Junghwan;Lee, Taeseok;Byun, Do-Young;Kim, Soon-Wook;Kim, Jeong-Sook
    • Journal of The Korean Astronomical Society
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    • v.50 no.6
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    • pp.167-178
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    • 2017
  • We present a study of the inexplicit connection between radio jet activity and ${\gamma}$-ray emission of BL Lacertae (BL Lac; 2200+420). We analyze the long-term millimeter activity of BL Lac via interferometric observations with the Korean VLBI Network (KVN) obtained at 22, 43, 86, and 129 GHz simultaneously over three years (from January 2013 to March 2016); during this time, two ${\gamma}$-ray outbursts (in November 2013 and March 2015) can be seen in ${\gamma}$-ray light curves obtained from Fermi observations. The KVN radio core is optically thick at least up to 86 GHz; there is indication that it might be optically thin at higher frequencies. To first order, the radio light curves decay exponentially over the time span covered by our observations, with decay timescales of $411{\pm}85$ days, $352{\pm}79$ days, $310{\pm}57$ days, and $283{\pm}55$ days at 22, 43, 86, and 129 GHz, respectively. Assuming synchrotron cooling, a cooling time of around one year is consistent with magnetic field strengths $B{\sim}2{\mu}T$ and electron Lorentz factors ${\gamma}$ ~ 10 000. Taking into account that our formal measurement errors include intrinsic variability and thus over-estimate the statistical uncertainties, we find that the decay timescale ${\tau}$ scales with frequency ${\nu}$ like ${\tau}{\propto}{\nu}^{-0.2}$. This relation is much shallower than the one expected from opacity effects (core shift), but in agreement with the (sub-)mm radio core being a standing recollimation shock. We do not find convincing radio flux counterparts to the ${\gamma}$-ray outbursts. The spectral evolution is consistent with the 'generalized shock model' of Valtaoja et al. (1992). A temporary increase in the core opacity and the emergence of a knot around the time of the second ${\gamma}$-ray event indicate that this ${\gamma}$-ray outburst might be an 'orphan' flare powered by the 'ring of fire' mechanism.

Development of an Improved Numerical Methodology for Design and Modification of Large Area Plasma Processing Chamber

  • Kim, Ho-Jun;Lee, Seung-Mu;Won, Je-Hyeong
    • Proceedings of the Korean Vacuum Society Conference
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    • 2014.02a
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    • pp.221-221
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    • 2014
  • The present work proposes an improved numerical simulator for design and modification of large area capacitively coupled plasma (CCP) processing chamber. CCP, as notoriously well-known, demands the tremendously huge computational cost for carrying out transient analyses in realistic multi-dimensional models, because electron dissociations take place in a much smaller time scale (${\Delta}t{\approx}10-8{\sim}10-10$) than time scale of those happened between neutrals (${\Delta}t{\approx}10-1{\sim}10-3$), due to the rf drive frequencies of external electric field. And also, for spatial discretization of electron flux (Je), exponential scheme such as Scharfetter-Gummel method needs to be used in order to alleviate the numerical stiffness and resolve exponential change of spatial distribution of electron temperature (Te) and electron number density (Ne) in the vicinity of electrodes. Due to such computational intractability, it is prohibited to simulate CCP deposition in a three-dimension within acceptable calculation runtimes (<24 h). Under the situation where process conditions require thickness non-uniformity below 5%, however, detailed flow features of reactive gases induced from three-dimensional geometric effects such as gas distribution through the perforated plates (showerhead) should be considered. Without considering plasma chemistry, we therefore simulated flow, temperature and species fields in three-dimensional geometry first, and then, based on that data, boundary conditions of two-dimensional plasma discharge model are set. In the particular case of SiH4-NH3-N2-He CCP discharge to produce deposition of SiNxHy thin film, a cylindrical showerhead electrode reactor was studied by numerical modeling of mass, momentum and energy transports for charged particles in an axi-symmetric geometry. By solving transport equations of electron and radicals simultaneously, we observed that the way how source gases are consumed in the non-isothermal flow field and such consequences on active species production were outlined as playing the leading parts in the processes. As an example of application of the model for the prediction of the deposited thickness uniformity in a 300 mm wafer plasma processing chamber, the results were compared with the experimentally measured deposition profiles along the radius of the wafer varying inter-electrode gap. The simulation results were in good agreement with experimental data.

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Mechanical Properties of a High-temperature Superconductor Bearing Rotor in a 10 kWh Class Superconductor Flywheel Energy Storage System (10 kWh급 초전도 베어링 회전자의 기계적 특성 평가)

  • Park, B.J.;Jung, S.Y.;Kim, C.H.;Han, S.C.;Park, B.C.;Han, S.J.;Doo, S.G.;Han, Y.H.
    • Progress in Superconductivity
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    • v.13 no.1
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    • pp.58-63
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    • 2011
  • Recently, superconductor flywheel energy storage systems (SFESs) have been developed for application to a regenerative power of train, a power quality improvement, the storage of distributed power sources such as solar and wind power, and a load leveling. As the high temperature superconductor (HTS) bearings offer dynamic stability without the use of active control, accurate analysis of the HTS bearing is very important for application to SFESs. Mechanical property of a HTS bearing is the main index for evaluating the capacity of an HTS bearing and is determined by the interaction between the HTS bulks and the permanent magnet (PM) rotor. HTS bearing rotor consists of PM and iron collector and the proper dimension design of them is very important to determine a supporting characteristics. In this study, we have optimized a rotor magnet array, which depends on the limited bulk size and performed various dimension layouts for thickness of the pole pitch and iron collector. HTS bearing rotor was installed into a single axis universal test machine for a stiffness test. A hydraulic pump was used to control the amplitude and frequency of the rotor vibration. As a result, the stiffness result showed a large difference more than 30 % according to the thickness of permanent magnet and iron collector. This is closely related to the bulk stiffness controlled by flux pining area, which is limited by the total bulk dimension. Finally, the optimized HTS bearing rotor was installed into a flywheel system for a dynamic stability test. We discussed the dynamic properties of the superconductor bearing rotor and these results can be used for the optimal design of HTS bearings of the 10kWh SFESs.

A Study on the Surface-Radiation Heat Transfer Characteristics in an Open Cavity with a Heat Source (발열체가 존재하는 개방된 정사각형공간에서 표면복사 열전달 특성에 관한 연구)

  • Nam, Pyoung-Woo;Park, Myoung-Sig;Park, Chan-Woo
    • Solar Energy
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    • v.12 no.3
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    • pp.70-83
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    • 1992
  • The interaction between the surface radiation and the mixed convection transport from an isolated thermal source, with a uniform surface heat flux input and located in a rectangular enclosure, is stuied numerically. The enclosure simulates a practical system such an air cooled electric device, where an air-stream flows through the openings on the two vertical walls. The heat source represents an electric component located in such an enclosure. The size of this cavity is $0.1[m]{\times}0.1[m]$. The inlet velocity is assumed as 0.07[m/s] and the inlet temperature is maintained as $27^{\circ}C$. The inflow is kept at a fixed position. Laminar, two dimensional flow is assumed, and the problem lies in the mixed convection regime, governed by buoyancy force and surface readiation. The significant variables include the location of the out-flow opening, of the heat source and the wall emissivity. The basic nature of the resulting interaction betwwn the externally induced air stream and the buoyancy-driven flow generated by the source is investigated. As a result, the best location of the heat source to make the active heat transfer is 0.075[m] from the left wall on the floor. The trends observed are also discussed in terms of heat removal from practical systems such as electric circuitry.

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A Study on Seolmunhaeja and Jeongyeokwonui′s Twelve Earthly branches. (설문해자(說文解字)와 정역원의(正易原義)의 십이지(十二支)에 관(關)한 연구(硏究))

  • Hong, Jin-Im;Yun, Chang-Yeol
    • Journal of Haehwa Medicine
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    • v.26 no.1
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    • pp.33-48
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    • 2017
  • Objective : Ten heavenly stems and twelve earthly branches are the important means to understand the orders of changes in heaven and earth. Method : We have so far looked into detailed explanations about twelve earthly branches in Seolmunhaeja, annotations in Seolmun of four major people, and commentaries in Jeongyeokwonui. Result & Conclusion : This can be also applied to the explanations of twelve early branches, as follows. In the $11^{th}$ month of the lunar calendar, the yang energy is finally born amid full of the ying energy. In the $12^{th}$ month, the yang energy prepares to break through the knots of the ying energy and gets ready to come out of the ground. In the first month, three kinds of the yang energy start to become vigorous and active. In the second month, the yang energy gains more force, sprouting various plants on the ground. In the third month, the yang energy arouse further, strengthening and growing plants. In the fourth month, all the yang energy is released, while the ying energy is still hiding. In the fifth month, one ying energy is born amid full of the yang energy, and there are interchanges between the yang energy and the ying energy. In the sixth month, the yang energy is still strong and vigorous, ripening the fruits in the fields. In the seventh month, the yang energy starts to hurt all creation. In the eighth month, the ying energy starts to flourish, and the yang energy starts to decline, diminishing all creation and, however, still ripening grains to be harvested. In the ninth month, one yang energy starts to hide from sight, not working its duty, while five kinds of the ying energy start to annihilate all creation. Finally, in the tenth month, the small yang energy hides to be rebirthed amid the flux and reflux of the ying-yang energy. The creative and unique interpretation of Jeongyeokwonui about twelve earthly branches is worth to be referred. It is definitely beyond the other existing explanations, as it incorporates trigrams and hexagrams from I Ching (Book of Changes) and the five primary substances.

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IMPLICATION OF STELLAR PROPER MOTION OBSERVATIONS ON RADIO EMISSION OF SAGITTARIUS A

  • CHANG HEON-YOUNG;CHOI CHUL-SUNG
    • Journal of The Korean Astronomical Society
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    • v.36 no.3
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    • pp.81-87
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    • 2003
  • It is suggested that a flying-by star in a hot accretion disk may cool the hot accretion disk by the Comptonization of the stellar emission. Such a stellar cooling can be observed in the radio frequency regime since synchrotron luminosity depends strongly on the electron temperature of the accretion flow. If a bright star orbiting around the supermassive black hole cools the hot disk, one should expect a quasi-periodic modulation in radio, or even possible an anti-correlation of luminosities in radio and X-rays. Recently, the unprecedentedly accurate infrared imaging of the Sagittarius A$\ast$ for about ten years enables us to resolve stars around it and thus determine orbital parameters of the currently closest star S2. We explore the possibility of using such kind of observation to distinguish two quite different physical models for the central engine of the Sagittarius A$\ast$, that is, a hot accretion disk model and a jet model. We have attempted to estimate the observables using the observed parameters of the star S2. The relative difference in the electron temperature is a few parts of a thousand at the epoch when the star S2 is near at the pericenter. The relative radio luminosity difference with and without the stellar cooling is also small of order $10^{-4}$, particularly even when the star S2 is near at the pericenter. On the basis of our findings we tentatively conclude that even the currently closest pass of the star S2 is insufficiently close enough to meaningfully constrain the nature of the Sagittarius A$\ast$ and distinguish two competing models. This implies that even though Bower et al. (2002)have found no periodic radio flux variations in their data set from 1981 to 1998, which is naturally expected from the presence of a hot disk, a hot disk model cannot be conclusively ruled out. This is simply because the energy bands they have studied are too high to observe the effect of the star S2 even if it indeed interacts with the hot disk. In other words, even if there is a hot accretion disk the star like S2 has imprints in the frequency range at v $\le$ 100 MHz.