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71.
S.?Mohammad?Mozaffari John?M.?SteeleEmail author 《Archive for History of Exact Sciences》2015,69(4):343-362
From the early ninth century until about eight centuries later, the Middle East witnessed a series of both simple and systematic astronomical observations for the purpose of testing contemporary astronomical tables and deriving the fundamental solar, lunar, and planetary parameters. Of them, the extensive observations of lunar eclipses available before 1000 AD for testing the ephemeredes computed from the astronomical tables are in a relatively sharp contrast to the twelve lunar observations that are pertained to the four extant accounts of the measurements of the basic parameters of Ptolemaic lunar model. The last of them are Taqī al-Dīn Mu?ammad b. Ma‘rūf’s (1526–1585) trio of lunar eclipses observed from Istanbul, Cairo, and Thessalonica in 1576–1577 and documented in chapter 2 of book 5 of his famous work, Sidrat muntaha al-afkar fī malakūt al-falak al-dawwār (The Lotus Tree in the Seventh Heaven of Reflection). In this article, we provide a detailed analysis of the accuracy of his solar (1577–1579) and lunar observations. 相似文献
72.
Mohammad Mohammadi 《Journal of forecasting》2017,36(7):859-866
The best prediction of generalized autoregressive conditional heteroskedasticity (GARCH) models with α‐stable innovations, α‐stable power‐GARCH models and autoregressive moving average (ARMA) models with GARCH in mean effects (ARMA‐GARCH‐M) are proposed. We present a sufficient condition for stationarity of α‐stable GARCH models. The prediction methods are easy to implement in practice. The proposed prediction methods are applied for predicting future values of the daily SP500 stock market and wind speed data. 相似文献
73.
74.
Martín-García R de León N Sharifmoghadam MR Curto MÁ Hoya M Bustos-Sanmamed P Valdivieso MH 《Cellular and molecular life sciences : CMLS》2011,68(17):2907-2917
Chs5p is a component of the exomer, a coat complex required to transport the chitin synthase Chs3p from the trans-Golgi network
to the plasma membrane. The Chs5p N-terminal region exhibits fibronectin type III (FN3) and BRCT domains. FN3 domains are
present in proteins that mediate adhesion processes, whereas BRCT domains are involved in DNA repair. Several fungi—including
Schizosaccharomyces pombe, which has no detectable amounts of chitin—have proteins similar to Chs5p. Here we show that the FN3 and BRCT motifs in Chs5p
behave as a module that is necessary and sufficient for Chs5p localization and for cargo delivery. The N-terminal regions
of S. cerevisiae Chs5p and S. pombe Cfr1p are interchangeable in terms of Golgi localization, but not in terms of exomer assembly, showing that the conserved
function of this module is protein retention in this organelle and that the interaction between the exomer components is organism-specific. 相似文献
75.
Surface roughness and shape play an important role on the behavior of particles in various processes such as flotation. In this research, the influence of different grinding methods on the surface roughness and shape characteristics of quartz particles as well as the effect of these parameters on the flotation of the particles was investigated. The surface roughness of the particles was determined by measuring their specific surface area via the gas adsorption method. The shape characteristics of the particles were measured and calculated by images obtained by scanning electron microscopy via an image analysis system. The flotation kinetics was determined using a laboratory flotation cell. The results showed that the particles of rod mill products have higher roughness and elongation ratio and lower roundness than the particles of ball mill products. The flotation kinetics constant of the particles increased with their surface roughness increasing. Particles with higher elongation and lower roundness indicated higher floatability. In addition, the influence of the surface roughness on the flotation kinetics was greater than that of shape parameters. 相似文献
76.
77.
Mohammad Zarbayani Esmaeil Jorjani Mirsaleh Mirmohammadi Mohammad Taghi Shadloo Mohammad Noaparast 《矿物冶金与材料学报》2010,17(3):251-256
Jajarm’s bauxite deposits are mainly diasporic, and they have a low mass ratio of Al2O3/SiO2. It is necessary to increase the run-of-mine mass ratio before feeding the material to the Bayer process. Chemical analysis indicated that the low-grade bauxite sample from Jajarm contained 43.9wt% Al2O3 and 13.35wt% SiO2, resulting in a mass ratio of 3.29. According to mineralogical studies, the presence of aluminosilicate minerals such as kaolinite, illite, and quartz was the main reason for the decrease of the mass ratio. Microscopic observations revealed that, with the size reduction from -1000+710 to -38 μm, the liberation degree of diaspore increased from 10% to 60%, and that of aluminosilicates increased from 20% to 85%. Heavy liquids with the densities of 2.8, 3.0, 3.2, and 3.4 g/cm3 were used to evaluate the heavy media separation in three sizes, i.e., -3350+710, -710+212, and -212+125 μm. Laboratory studies confirm that the density of 3.2 g/cm3 can produce the concentrates (in sunk fractions) with recoveries of 89.09%, 91.24%, and 84.68% with the Al2O3/SiO2 mass ratios of 5.03, 5.16, and 5.15 for the -3350+710, -710+212, and -212+125 μm sizes, respectively. 相似文献
78.
The production of MoO3 from Sarcheshmeh molybdenite concentrate via a pyro-hydrometallurgical process was studied. The molybdenite concentrate and sodium carbonate were premixed and fused under air atmosphere. Then the fused products were leached in water and the dissolved molybdenum was recovered as ammonium molybdate. The ammonium molybdate was then calcined to produce molybdic oxide. At the fusion stage, the effect of the mass ratio of carbonate to sulfide on the reaction products and the solubility of the products was investigated. The results show that during the fusion, sodium molybdate and sodium sulfate are the final reaction products and sodium sulfide is detected as an intermediate reaction product. By melting at 850℃ with 5wt% excess carbonate, the maximum solubility of the products is obtained. The molybdenum is recovered from the solutions as ammonium molybdate. 相似文献
79.
Budde BS Namavar Y Barth PG Poll-The BT Nürnberg G Becker C van Ruissen F Weterman MA Fluiter K te Beek ET Aronica E van der Knaap MS Höhne W Toliat MR Crow YJ Steinling M Voit T Roelenso F Brussel W Brockmann K Kyllerman M Boltshauser E Hammersen G Willemsen M Basel-Vanagaite L Krägeloh-Mann I de Vries LS Sztriha L Muntoni F Ferrie CD Battini R Hennekam RC Grillo E Beemer FA Stoets LM Wollnik B Nürnberg P Baas F 《Nature genetics》2008,40(9):1113-1118
Pontocerebellar hypoplasias (PCH) represent a group of neurodegenerative autosomal recessive disorders with prenatal onset, atrophy or hypoplasia of the cerebellum, hypoplasia of the ventral pons, microcephaly, variable neocortical atrophy and severe mental and motor impairments. In two subtypes, PCH2 and PCH4, we identified mutations in three of the four different subunits of the tRNA-splicing endonuclease complex. Our findings point to RNA processing as a new basic cellular impairment in neurological disorders. 相似文献
80.
Bandwidth optimization of a Planar Inverted-F Antenna using binary and real coded genetic algorithms
With the exponential development of mobile communications and the miniaturization of radio frequency transceivers, the need for small and low profile antennas at mobile frequencies is constantly growing. Therefore, new antennas should be developed to provide larger bandwidth and at the same time small dimensions. Although the gain in bandwidth performances of an antenna are directly related to its dimensions in relation to the wavelength, the aim is to keep the overall size of the antenna constant and from there, find the geometry and structure that give the best performance. The design and bandwidth optimization of a Planar Inverted-F Antenna (PIFA) were introduced in order to achieve a larger bandwidth in the 2 GHz band, using two optimization techniques based upon genetic algorithms (GA), namely the Binary Coded GA (BCGA) and Real-Coded GA (RCGA). During the optimization process, the different PIFA models were evaluated using the finite-difference time domain (FDTD) method-a technique belonging to the general class of differential time domain numerical modeling methods. 相似文献