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The conversion of an organometallic compound into an intercalated thin-layer amorphous structure
Othman, M. R.,Fernando, W. J. N.,Kim, J. John Wiley Sons, Ltd. 2009 Applied Organometallic Chemistry Vol.23 No.10
<P>A thin alumina-hydrotalcite (Al-HT) film was fabricated from the synthesized boehmite and HT sol samples. The sols were a Newtonian fluid within 12 h of the sol synthesis and pseudo-plastic flow thereon. Co-precipitated HT demonstrated poorly crystallized periclase and spinel structures and apparent doublet peak of hydrotalcite at 2&thetas; = 39–44°, indicative of a disordered structure. The heated Al-HT sample demonstrated highly amorphous structure with single hydrotalcite peak but barely observed γ-alumina and γ-boehmite phases. The exfoliation of the spinel, gibbsite and periclase in the Al-HT was caused by the intercalation of boehmite into the HT layers that impeded the formation of the oxides phases. Copyright © 2009 John Wiley & Sons, Ltd.</P> <B>Graphic Abstract</B> <P>SEM images of thin (Al<SUB>2</SUB>O<SUB>3</SUB>)<SUB>0.98</SUB>[Mg<SUB>6</SUB>Al<SUB>2</SUB>(OH)<SUB>2</SUB>]<SUB>0.02</SUB> layer deposited by dip coating on a porous alumina (200 nm) that was used as a support material are shown. The Al-HT layer with thickness of 3–6 µm displays distinguishing denser, smoother surfaces and a more closely packed microstructure than its support material. <img src='wiley_img/02682605-2009-23-10-AOC1532-gra001.gif' alt='wiley_img/02682605-2009-23-10-AOC1532-gra001'> </P>
M. R. Othman,J. Kim 한국물리학회 2008 THE JOURNAL OF THE KOREAN PHYSICAL SOCIETY Vol.52 No.4
The development of CO₂ mono and multi-molecular layer adsorption was virtually impossible at relatively low △T and thin porous media, where the flow was predominantly laminar. Only sub-molecular layer coverage was achieved in this flow region. In a transient state, a multi-molecular layer of adsorption occurred at an accelerated pace even at low △T or increasing surface temperature. Ten of thousands of CO₂ molecules stacked up to form arrays of cohesive multi-molecular layers on the pore wall to completely fill up the micro and the meso-pore spaces and to partially fill up the macro-pores at △T = 5 K. The calculated adsorption of CO₂ from convective models was significantly higher in the turbulent system, in the order of 1 ×10 -7 -- 6 × 10 -6 kg/s in the region of △T = 15 -- 100 K. The adsorption rate increased with increasing △T and the adsorption film thickness increased with increasing pore length. The surface diffusivity also increased with increasing △T , regardless of the flow region. The development of CO₂ mono and multi-molecular layer adsorption was virtually impossible at relatively low △T and thin porous media, where the flow was predominantly laminar. Only sub-molecular layer coverage was achieved in this flow region. In a transient state, a multi-molecular layer of adsorption occurred at an accelerated pace even at low △T or increasing surface temperature. Ten of thousands of CO₂ molecules stacked up to form arrays of cohesive multi-molecular layers on the pore wall to completely fill up the micro and the meso-pore spaces and to partially fill up the macro-pores at △T = 5 K. The calculated adsorption of CO₂ from convective models was significantly higher in the turbulent system, in the order of 1 ×10 -7 -- 6 × 10 -6 kg/s in the region of △T = 15 -- 100 K. The adsorption rate increased with increasing △T and the adsorption film thickness increased with increasing pore length. The surface diffusivity also increased with increasing △T , regardless of the flow region.
Shabanah, Othman A AL,Alotaibi, Moureq R,Rejaie, Salim S Al,Alhoshani, Ali R,Almutairi, Mashal M,Alshammari, Musaad A,Hafez, Mohamed M Asian Pacific Journal of Cancer Prevention 2016 Asian Pacific journal of cancer prevention Vol.17 No.11
Objective: Breast cancer is global female health problem worldwide. Most of the currently used agents for breast cancer treatment have toxic side-effects. Ginseng root, an oriental medicine, has many health benefits and may exhibit direct anti-cancer properties. This study was performed to assess the effects of ginseng on breast cancer cell lines. Materials and Methods: Cytotoxicity of ginseng extract was measured by MTT assay after exposure of MDA-MB-231, MCF-10A and MCF-7 breast cancer cells to concentrations of 0.25, 0.5, 1, 1.5, 2 and 2.5 mg/well. Expression levels of p21WAF, p16INK4A, Bcl-2, Bax and P53 genes were analyzed by quantitative real time PCR. Results: The treatment resulted in inhibition of cell proliferation in a dose-and time-dependent manner. p53, p21WAF1and p16INK4A expression levels were up-regulated in ginseng treated MDA-MB-231 and MCF-7 cancer cells compared to untreated controls and in MCF-10A cells. The expression levels of Bcl2 in the MDA-MB-231 and MCF-7 cells were down-regulated. In contrast, that of Bax was significantly up-regulated. Conclusion: The results of this study revealed that ginseng may inhibit breast cancer cell growth by activation of the apoptotic pathway.
First upper limits on the radar cross section of cosmic-ray induced extensive air showers
Abbasi, R.U.,Abe, M.,Abou Bakr Othman, M.,Abu-Zayyad, T.,Allen, M.,Anderson, R.,Azuma, R.,Barcikowski, E.,Belz, J.W.,Bergman, D.R.,Besson, D.,Blake, S.A.,Byrne, M.,Cady, R.,Chae, M.J.,Cheon, B.G.,Chib North-Holland 2017 Astroparticle physics Vol.87 No.-
<P>TARA (Telescope Array Radar) is a cosmic ray radar detection experiment colocated with Telescope Array, the conventional surface scintillation detector (SD) and fluorescence telescope detector (FD) near Delta, Utah, U.S.A. The TARA detector combines a 40 kW, 54.1 MHz VHF transmitter and high-gain transmitting antenna which broadcasts the radar carrier over the SD array and within the FD field of view, towards a 250 MS/s DAQ receiver. TARA has been collecting data since 2013 with the primary goal of observing the radar signatures of extensive air showers (EAS). Simulations indicate that echoes are expected to be short in duration (similar to 10 mu s) and exhibit rapidly changing frequency, with rates on the order 1 MHz/mu s. The EAS radar cross-section (RCS) is currently unknown although it is the subject of over 70 years of speculation. A novel signal search technique is described in which the expected radar echo of a particular air shower is used as a matched filter template and compared to waveforms obtained by triggering the radar DAQ using the Telescope Array fluorescence detector. No evidence for the scattering of radio frequency radiation by EAS is obtained to date. We report the first quantitative RCS upper limits using EAS that triggered the Telescope Array Fluorescence Detector. (C) 2016 Elsevier B.V. All rights reserved.</P>
Othman, A. E.,Brockmann, C.,Yang, Z.,Kim, C.,Afat, S.,Pjontek, R.,Nikoubashman, O.,Brockmann, M. A.,Nikolaou, K.,Wiesmann, M. SPRINGER INTERNATIONAL 2016 EUROPEAN RADIOLOGY Vol.26 No.1
<P>To examine the impact of denoising on ultra-low-dose volume perfusion CT (ULD-VPCT) imaging in acute stroke. Simulated ULD-VPCT data sets at 20 % dose rate were generated from perfusion data sets of 20 patients with suspected ischemic stroke acquired at 80 kVp/180 mAs. Four data sets were generated from each ULD-VPCT data set: not-denoised (ND); denoised using spatiotemporal filter (D1); denoised using quanta-stream diffusion technique (D2); combination of both methods (D1 + D2). Signal-to-noise ratio (SNR) was measured in the resulting 100 data sets. Image quality, presence/absence of ischemic lesions, CBV and CBF scores according to a modified ASPECTS score were assessed by two blinded readers. SNR and qualitative scores were highest for D1 + D2 and lowest for ND (all p a parts per thousand currency signaEuro parts per thousand 0.001). In 25 % of the patients, ND maps were not assessable and therefore excluded from further analyses. Compared to original data sets, in D2 and D1 + D2, readers correctly identified all patients with ischemic lesions (sensitivity 1.0, kappa 1.0). Lesion size was most accurately estimated for D1 + D2 with a sensitivity of 1.0 (CBV) and 0.94 (CBF) and an inter-rater agreement of 1.0 and 0.92, respectively. An appropriate combination of denoising techniques applied in ULD-VPCT produces diagnostically sufficient perfusion maps at substantially reduced dose rates as low as 20 % of the normal scan. aEuro cent Perfusion-CT is an accurate tool for the detection of brain ischemias. aEuro cent The high associated radiation doses are a major drawback of brain perfusion CT. aEuro cent Decreasing tube current in perfusion CT increases image noise and deteriorates image quality. aEuro cent Combination of different image-denoising techniques produces sufficient image quality from ultra-low-dose perfusion CT.</P>
Othmane Allam,Kada Draiche,Abdelmoumen Anis Bousahla,Fouad Bourada,Abdeldjebbar Tounsi,Kouider Halim Benrahou,S.R. Mahmoud,E.A. Adda Bedia,Abdelouahed Tounsi 사단법인 한국계산역학회 2020 Computers and Concrete, An International Journal Vol.26 No.2
This research is devoted to investigate the bending and free vibration behaviour of laminated composite/sandwich plates and shells, by applying an analytical model based on a generalized and simple refined higher-order shear deformation theory (RHSDT) with four independent unknown variables. The kinematics of the proposed theoretical model is defined by an undetermined integral component and uses the hyperbolic shape function to include the effects of the transverse shear stresses through the plate/shell thickness; hence a shear correction factor is not required. The governing differential equations and associated boundary conditions are derived by employing the principle of virtual work and solved via Navier-type analytical procedure. To verify the validity and applicability of the present refined theory, some numerical results related to displacements, stresses and fundamental frequencies of simply supported laminated composite/sandwich plates and shells are presented and compared with those obtained by other shear deformation models considered in this paper. From the analysis, it can be concluded that the kinematics based on the undetermined integral component is very efficient, and its use leads to reach higher accuracy than conventional models in the study of laminated plates and shells.
Technologies for production of biodiesel focusing on green catalytic techniques: A review
Helwani, Z.,Othman, M.R.,Aziz, N.,Fernando, W.J.N.,Kim, J. Elsevier Scientific Pub. Co 2009 Fuel processing technology Vol.90 No.12
Biodiesel production is undergoing rapid technological reforms in industries and academia. This has become more obvious and relevant since the recent increase in the petroleum prices and the growing awareness relating to the environmental consequences of the fuel overdependency. In this paper, various technological methods to produce biodiesel being used in industries and academia are reviewed. Catalytic transesterification, the most common method in the production of biofuel, is emphasized in the review. The two most common types of catalysts; homogeneous liquids and heterogeneous solids, are discussed at length in the paper. Two types of processes; batch and continuous processes, are also presented. Although batch production of biodiesel is favored over continuous process in many laboratory and larger scale efforts, the latter is expected to gain wider acceptance in the near future, considering its added advantages associated with higher production capacity and lower operating costs to ensure long term supply of biodiesel.