$
\begin{gathered}
3H_2 WO_4^0 \leftrightarrow H_3 W_3 O_{12}^{3 - } + 3H^ + \log K_p = - 7.5 \pm 0.1, \hfill \\
3H_2 WO_4^0 \leftrightarrow W_3 O_9^{3 - } + 1.5H_2 O + 3H^ + + 0.75O_2 \log K_p = - 25.7 \pm 0.2, \hfill \\
5H_2 WO_4^0 \leftrightarrow \left[ {W^V W_4^{VI} O_{16} } \right]^{3 - } + 3H^ + + 3.5H_2 O + 0.25O_2 \log K_p = - 4.6 \pm 0.1 \hfill \\
\end{gathered}
$
\begin{gathered}
3H_2 WO_4^0 \leftrightarrow H_3 W_3 O_{12}^{3 - } + 3H^ + \log K_p = - 7.5 \pm 0.1, \hfill \\
3H_2 WO_4^0 \leftrightarrow W_3 O_9^{3 - } + 1.5H_2 O + 3H^ + + 0.75O_2 \log K_p = - 25.7 \pm 0.2, \hfill \\
5H_2 WO_4^0 \leftrightarrow \left[ {W^V W_4^{VI} O_{16} } \right]^{3 - } + 3H^ + + 3.5H_2 O + 0.25O_2 \log K_p = - 4.6 \pm 0.1 \hfill \\
\end{gathered}
相似文献
8.
The paper considers some petrological and geochemical aspects of the formation of oceanic plagiogranites (OPG)—felsic intrusive
rocks, which were found in the plutonic complexes of modern mid-ocean ridges (MOR) and ophiolites of paleo-collisional zones.
Based on the multi-equilibrium clinopyroxene-orthopyroxene-amphibole-plagioclase geothermobarometry, typical OPG found in
gabbros and peridotites were formed at temperatures of 820–850°C and pressure of 2–2.5 kbar. Close temperature estimates (825
± 50°C) were obtained from literature data on Ti content in zircon, with allowance for lowered TiO2 activity in the rock. Under these P-T parameters, OPG can be generated only in the presence of fluid of water activity $
\left( {a_{H_2 O} } \right)
$
\left( {a_{H_2 O} } \right)
close to 0.9. OPG and associated recrystallized gabbroids contain high-temperature hornblende with significant Cl content
(0.5–2 wt %). In addition, the plagiogranites are characterized by particular geochemical features such as extremely high
Na2O/K2O (up to 135), sharp LREE enrichment ((Ce/Yb)cn and (La/Sm)cn up to 10 and 4, respectively), and elevated 87Sr/86Sr ratio relative to DMM. All these facts point to the key role of hydrothermal fluid, the seawater derivative, in the OPG
formation. The fluid with $
a_{H_2 O} = 0.9
$
a_{H_2 O} = 0.9
(approximately 28 wt % NaCl) could be produced from seawater due to hydration reactions at the higher lower temperature horizons
of oceanic crust in the course of its percolation to the OPG generation areas. The formation of plagiogranites in the MOR
oceanic core complexes possibly reflects the fundamental feature of oceanic accretion: practically simultaneous (at the geological
time scale) proceeding of exogenic (neptunic) and endogenous (plutonic) processes. 相似文献
9.
E. N. Vinyaikin 《Astronomy Reports》2007,51(7):570-576
Radio flux measurements of the Crab nebula have been performed over many years relative to Orion A at 927 MHz and relative to Cygnus A and Virgo A at 151.5 MHz. The inferred average secular rates of decrease in the radio flux of the Crab nebula are d 927 MHz = ?0.18 ± 0.10% yr?1 over 1977–2000 and d 151.5 MHz = ?0.3 ± 0.1% yr?1 over 1980–2003. The weighted mean flux-decrease rate averaged over several years of relative measurements at 86, 151.5, 927, and 8000 MHz is d mw = ?0.17 ± 0.02% yr?1. The secular flux decrease is frequency independent, with an upper limit of |dα/dt| < 3 × 10?4 yr?1 for the absolute value of the rate of change of the spectral index, and remains constant in time when averaged over long time intervals. The results of our measurements at 151.5 and 927 MHz combined with published absolute measurements at 81.5 and 8250 MHz are used to determine the radio spectrum of the Crab nebula for epoch 2010.0. 相似文献
10.
We perform a statistical analysis of the properties of 170 rich clusters of galaxies. We confirm the existence of correlations
between the X-ray luminosity and temperature of the cluster intergalactic medium (IGM) and between the velocity dispersion
of the galaxies and the X-ray luminosity of the IGM. In addition, we have found a new anti-correlation between the optical
luminosity in Hα and the X-ray luminosity of the cluster IGM: log $
\left( {\frac{{L_{H\alpha } }}
{{L_ \odot }}} \right) = a - b\log \left( {\frac{{L_x }}
{{L_ \odot }}} \right)
$
\left( {\frac{{L_{H\alpha } }}
{{L_ \odot }}} \right) = a - b\log \left( {\frac{{L_x }}
{{L_ \odot }}} \right)
. Clusters form sequences with different values of a but similar values of b. 相似文献
11.
A. D. Kuz’min B. Ya. Losovskii S. V. Logvinenko I. I. Litvinov 《Astronomy Reports》2008,52(11):910-916
Our measurements of the arrival-time delays of radio pulses from the Crab pulsar, PSR B0531+21, at low frequencies 111, 63, and 44 MHz revealed additional delays compared to the usual quadratic frequency relation, Δt(v) ∝ v ?2. These additional delays are 65 ms between 63 MHz and 111 MHz—i.e., a factor of two longer than the pulsar’s period, i.e., a factor of five longer than the pulsar period—and cannot be explained by the “twisting” of the magnetic-field lines by the rotation of the pulsar. We suggest the model in which a previously unknown high-density plasma layer with a high electron concentration is present along the line of sight in the Crab nebula, causing an additional frequency-dependent delay of the observed radio pulses at low frequencies due to the contribution of the n e 2 v ?4 term in the dispersion-delay formula. The parameters of this inferred layer have been derived: emission measure EM ? 4 × 106 pc/cm6, electron density n e ? 106 cm?3, depth along the line of sight d ? 4 × 10?6 pc, and electron temperature T e ≥ 2 × 106 K. 相似文献
12.
N. V. Chukanov R. K. Rastsvetaeva I. V. Pekov A. E. Zadov R. Allori N. V. Zubkova G. Giester D. Yu. Puscharovsky K. V. Van 《Geology of Ore Deposits》2009,51(7):588-594
Biachellaite, a new mineral species of the cancrinite group, has been found in a volcanic ejecta in the Biachella Valley,
Sacrofano Caldera, Latium region, Italy, as colorless isometric hexagonal bipyramidal-pinacoidal crystals up to 1 cm in size
overgrowing the walls of cavities in a rock sample composed of sanidine, diopside, andradite, leucite and hauyne. The mineral
is brittle, with perfect cleavage parallel to {10$
\bar 1
$
\bar 1
0} and imperfect cleavage or parting (?) parallel to {0001}. The Mohs hardness is 5. Dmeas = 2.51(1) g/cm3 (by equilibration with heavy liquids). The densities calculated from single-crystal X-ray data and from X-ray powder data
are 2.515 g/cm3 and 2.520 g/cm3, respectively. The IR spectrum demonstrates the presence of SO42−, H2O, and absence of CO32−. Biachellaite is uniaxial, positive, ω = 1.512(1), ɛ = 1.514(1). The weight loss on ignition (vacuum, 800°C, 1 h) is 1.6(1)%.
The chemical composition determined by electron microprobe is as follows, wt %: 10.06 Na2O, 5.85 K2O, 12.13 CaO, 26.17 Al2O3, 31.46 SiO2, 12.71 SO3, 0.45 Cl, 1.6 H2O (by TG data), −0.10 −O=Cl2, total is 100.33. The empirical formula (Z = 15) is (Na3.76Ca2.50K1.44)Σ7.70(Si6.06Al5.94O24)(SO4)1.84Cl0.15(OH)0.43 · 0.81H2O. The simplified formula is as follows: (Na,Ca,K)8(Si6Al6O24)(SO4)2(OH)0.5 · H2O. Biachellaite is trigonal, space group P3, a =12.913(1), c = 79.605(5) ?; V = 11495(1) ?3. The crystal structure of biachellaite is characterized by the 30-layer stacking sequence (ABCABCACACBACBACBCACBACBACBABC)∞. The tetrahedral framework contains three types of channels composed of cages of four varieties: cancrinite, sodalite, bystrite
(losod) and liottite. The strongest lines of the X-ray powder diffraction pattern [d, ? (I, %) (hkl)] are as follows: 11.07 (19) (100, 101), 6.45 (18) (110, 111), 3.720 (100) (2.1.10, 300, 301, 2.0.16, 302), 3.576 (18) (1.0.21,
2.0.17, 306), 3.300 (47) (1.0.23, 2.1.15), 3.220 (16) (2.1.16, 222). The type material of biachellaite has been deposited
at the Fersman Mineralogical Museum of the Russian Academy of Sciences, Moscow, Russia, registration number 3642/1. 相似文献
13.
The data of the bottom “summit” surface were used for compiling the schematic structural-neotectonic map and map of the main
neotectonic structural elements. Their comparison with the schematic paleogeographic maps of the lithophysical complexes for
four periods (K2-$
_{1 - 2}
$
_{1 - 2}
, $
\rlap{--} P_3
$
\rlap{--} P_3
-N11, N11–2, and N13-N2) reveals that the largest part of the considered area was characterized by either a continental or relatively shallow-sea
environment, except for the western areas occupied at that time by the relatively deep trough with its axis located substantially
westward of the neotectonic Deryugin Basin and the Staritskii Trough. In the Late Pliocene, the deep paleotrough ($
\rlap{--} P_3
$
\rlap{--} P_3
-N22) and Deryugin Basin were likely occupied by shelf settings with continuing sedimentation. The paleogeographic environments
of the area for the period from the terminal Pliocene to the late Riss (Taz) Glaciation (Q26; MIS6) are unknown so far. The most complete Quaternary section recovered by Core LV 28-34-2 consists of six units; the odd
(1, 3, and 5) and even (2, 4, and 6) among them correspond to the warm and cold marine isotopic stages, respectively. Judging
from the benthic foraminiferal assemblages, the water depths during cold periods were shallower as compared with the warm
stages, which is explained by the respective ascending and descending bottom movements and, partially, by the eustatic sea
level fluctuations. In the Late Pleistocene-Holocene (∼17 ka), the bottom of the Deryugin Basin and the summit part of the
Institut Okeanologii Rise subsided with average rates of 8 and 3 cm/year, respectively. 相似文献
14.
The pulsar PSR B2111+46 has been observed at 112 MHz, and a new approach to analyzing pulsar pulses scattered in turbulent
interstellar plasma applied. This method is based on the dependence of the normalized energy in the trailing part of a pulse
on the intrapulse time. Since the trailing edge of a pulse follow exponential law to high accuracy, the inner turbulence scale
of the interstellar plasma exceeds the field coherence scale. The measured scattering parameter is τ
sc
= 147 ± 1 ms. Analysis of the parameters of diffractive and refractive scintillations of the pulsar at 610 MHz together with
the 112 MHz data shows that the spectrum of the interstellar plasma toward PSR B2111+46 is a piecewise power law: on scales
of 1013–1014 cm, the exponent of the turbulence spectrum is n ≃ 4, whereas n = 3.5 on scales of 2 × 108−1013 cm. The spectrum flattens with approach to the inner turbulence scale l: n = 3–3.2. The obtained inner turbulence scale is l = (3.5 ± 1.5) × 107 cm. The distribution of the interstellar plasma toward the pulsar is close to statistically homogeneous. The local density
(N
e
= 0.4 cm−3) and filling factor (F = 0.04) of the interstellar plasma have been estimated. The similarity of N
e
estimates obtained from the inner scale of the inhomogeneities and the ratio of the emission measure to the dispersion measure
provides evidence that the inner turbulence scale corresponds to the ion inertial length. 相似文献
15.
Solubility curves of water-hydrogen fluid were studied using a high-pressure gas apparatus at a pressure of 200 MPa under
variable fluid composition in haplogranite (Ab
39
Or
32
Qtz
29, 950°C), Na-disilicate (Na2Si2O5, 950°C), and albite melts (1200°C). The mole fraction of hydrogen in experiments was controlled directly by Ar-H2 mixtures using a specially designed cell with a Shaw membrane. $
X_{H_2 }^{Ar - H_2 }
$
X_{H_2 }^{Ar - H_2 }
ranged from 0 to 1. In some experiments with haplogranite and Na-disilicate melts under oxidizing conditions, in order to
increase the accuracy of experimental parameters, the fugacities of oxygen and hydrogen were controlled using the double-capsule
technique and the solid-phase buffer mixtures Ni-NiO (NNO) and Co-CoO (CCO). The addition of H2 to the H2O-saturated systems ($
X_{H_2 }^{H_2 O - H_2 }
$
X_{H_2 }^{H_2 O - H_2 }
≥ 0.012) results in the appearance of a distinct maximum on the solubility curves at $
X_{H_2 }^{H_2 O - H_2 }
$
X_{H_2 }^{H_2 O - H_2 }
= 0.05–0.07 (H2 mole fractions were calculated for real H2O-H2 mixtures of real gases), and the maximum content of H2O-H2 fluid increases relative to the H2O-saturated melts by 1.51 wt % for haplogranite melt at $
X_{H_2 }
$
X_{H_2 }
= 0.063, 2.68 wt % for albite melt at $
X_{H_2 }
$
X_{H_2 }
= 0.066, and 3.54 wt % for Na-disilicate melt at $
X_{H_2 }
$
X_{H_2 }
= 0.067. A further increase in H2 content in the gas mixture decreases the solubility of H2O-H2 fluid in the melts, and under pure H2 pressure, the contents of fluid components are 0.08 wt % in haplogranite melt and 0.06 wt % in albite melt. The 1H NMR study of aluminosilicate and Na-silicate glasses obtained under the pressure of H2O and H2O-H2 fluids suggests different mechanisms of the dissolution of H2O and H2O-H2 fluids in magmatic melts. In addition to the spectra of dissolved water fluid, the spectra of quenched glasses synthesized
under H2O-H2 fluid pressure exhibited a narrow line of molecular hydrogen with a width at half height of 1.8–2.0 kHz at $
X_{H_2 }
$
X_{H_2 }
≥ 0.653 for albite and $
X_{H_2 }
$
X_{H_2 }
≥ 0.063 for Na-disilicate and two lines at $
X_{H_2 }
$
X_{H_2 }
≥ 0.063 for the haplogranite composition. 相似文献
16.
Radio Sources in the Central Section of the RZF Catalog. Search for Objects with Ultra-Steep Spectra
Results of reducing and selecting data from the Ratan Zenith Field (RZF) are presented. A deep survey in the region 0h ≤ R.A. ≤ 24h, 40.5° ≤ DEC ≤ 42.5° carried out on the RATAN-600 radio telescope was used. Within +2′ of the center of the survey region, 448 objects were detected, 69 of them with ultra-steep spectra (USS). The SDSS digital optical survey (DR12), NVSS radio maps, and the FIRST catalogs have been used to cross-identify 208 radio sources from the RZF catalog, obtained as part of the “Genetic Code of the Universe” project. The characteristics of these objects are studied, and the distribution of the SDSS galaxies in a two-color diagram is obtained. Photometric redshifts and radio luminosities at 3940 and 1400 MHz are determined for 27 objects with spectral indices α < −1.1 (S ∝ να) for which magnitudes in various filters are presented in the SDSS. In the sample of USS objects, 12 galaxies have redshifts z < 0.5, are detected at wavelength λ = 7.6 cm, and have relatively high radio luminosities (type FR II or intermediate type FR I–FR II). Only one radio galaxy proved to be a rare nearby galaxy with relatively low radio luminosity L1400 MHz = 1.51 × 1024 W/Hz (type FR I). Two objects are candidate GHz-Peaked Spectrum objects. 相似文献17.
The pulse structure of the pulsar B1822-09 has been studied at 112, 62, and 42 MHz. The observations were conducted in 2010
on the Large Scanning Antenna and the DKR-1000 radio telescope of the Pushchino Radio Astronomy Observatory. The shape of
the main pulse and interpulse undergo considerable changes at low radio frequencies. In the main pulse, the precursor disappears
and is replaced by a new component that trails 50 ms behind the main component. At 62 MHz, the interpulse acquires a pronounced
two-peaked shape. At 62 and 112 MHz, as well as at higher frequencies, the brighter second component of the interpulse follows
the main pulse at 185° and has a relative amplitude of about 5%. The main pulse width changes with frequency according to
the power law W
0.5 ∼ ν
−0.15 in the frequency range 42–4750-MHz. The interpulse width follows this law only in the range 325–4750 MHz; at 112, 102, and
62 MHz, the interpulse is almost a factor of three broader than themain pulse. The parameters of the pulse’s scattering on
interstellar plasma inhomogeneities and the initial pulse width before it enters the scattering medium have been measured
at 62 and 42 MHz. The frequency dependence of the characteristic scale for scattering of the pulses of B1822-09 corresponds
to a Kolmogorov spectrum for the electron-density fluctuations in the interstellar medium in the direction toward this pulsar. 相似文献
18.
M. A. Kharinov A. M. Finkel’shteĭn A. V. Ipatov O. A. Tsiopa Yu. N. Gnedin M. Yu. Piotrovich 《Astronomy Reports》2010,54(9):853-860
Results of radio observations of the cosmic gamma-ray burst GRB 080319B at 8.45 GHz during the afterglow are reported. The
observations were carried out on telescopes of the Zelenchukskaya and Svetloe Observatories of the Institute of Applied Astronomy,
Russian Academy of Sciences. Two outbursts in the radio brightness were detected in the afterglow of GRB 080319B. A total
of 148 radio observations were performed at 3.5, 6.2, and 13 cm. The observations were conducted in a mode with smooth scanning
in elevation, which was also used to update the flux densities of the primary reference sources. The first powerful radio
outburst was recorded on March 28, 2008, 6.86d after the gamma-ray burst, when the maximum flux density was F
8.45 GHz = 44 ± 12 mJy. Almost two months later, a second increase in the radio brightness was observed. The flux density monotonically
increased from 19 mJy (59.55d) to 34mJy (59.79d) over 6.5 h; 1.17 d later, the flux density fell to 12mJy.At this last epoch, the radio flux demonstrated variability within
3σ on timescales of 9d−10d. The detected radio brightness increases are interpreted in terms of MHD interactions of a fast plasma outflow with a cloud
of inhomogeneous surrounding medium. This interaction is accompanied by restructuring of the relativistic plasma outflow;
the analysis of this process has been carried out. 相似文献
19.
N. V. Chukanov O. V. Yakubovich I. V. Pekov D. I. Belakovsky W. Massa 《Geology of Ore Deposits》2008,50(8):713-719
Britvinite, a new mineral species, has been found in manganese ore at the Långban deposit, Bergslagen ore district, Filipstad, Värmland County, Sweden. Calcite, barytocalcite, brucite, cerussite, and hausmannite are associated minerals. Britvinite occurs as pale yellow to colorless transparent plates with a white streak up to 0.2 × 0.5 × 0.5 mm in size, which are flat parallel to {001}; the luster is adamantine. Thin lamellae are flexible, whereas thick ones are brittle; the Mohs hardness is 3. The cleavage is eminent parallel to {001}. The calculated density is 5.51 g/cm3. In the infrared spectrum of the new mineral, the bands of (OH)?, (CO3)2?, and (BO3)3? are recorded, whereas those corresponding to water molecules are absent. Britvinite is optically biaxial and negative, α = 1.896(2), β = 1.903(2), γ = 1.903(2), 2Vmeas = 20(10), Z≈c. Dispersion is strong, r<v. The chemical composition (electron microprobe; H2O determined with the Alimarin method, CO2, with selective sorption) is (wt %) 7.95 MgO, 71.92 PbO, 0.41 Al2O3, 12.77 SiO2, 2.2 H2O, 2.1 CO2, 2.67 B2O3 (calculated on the basis of structural data); total 100.02. The empirical formula calculated on the basis of 59 anions (O + OH) (Z = 1) is as follows: Pb14.75Mg9.03Si9.73Al0.37O30.76(BO3)3.51(CO3)2.18(OH)11.7. The simplified formula (Z = 2) is Pb7 + x Mg4.5(Si5O14)(BO3)2(CO3)(OH,O)7 (x < 0.5). The crystal structure of britvinite has been studied on a single crystal at 173 K; R = 0.0547. The new mineral is triclinic, space group P $ \bar 1
20.
Observations of the RRAT pulsars J0627+16, J0628+09, J1819?1458, J1826?1419, J1839?01, J1840?1419, J1846?0257, J1848?12, J1850+15, J1854+0306, J1919+06, J1913+1330, J1919+17, J1946+24, and J2033+00 observed earlier on the 64-m Parkes telescope (Australia) and the 300-m Arecibo radio telescope (Puerto Rico) at 1400 MHz were conducted at 111 MHz on the LSA radio telescope of the Pushchino Radio Astronomy observatory in 2010–2012. A characteristic feature of these pulsars is their sporadic radio emission during rare active epochs and the absence of radio emission during long time intervals. No appreciable flare activity of these pulsars was detected in the Pushchino observations. However, processing the observations using the Fast Folding Algorithm taking into account known information about the pulsar dispersion measures and periods shows that, even during quiescent intervals, the majority of the studied pulsars generate weak radio pulses with a period corresponding to that of the radio emission of the sporadic pulses observed at active epochs. The flux of this radio emission does not exceed 100 mJy at the pulse peak, even at the low frequency of 111 MHz. This considerably hinders detection of the radio emission of RRAT pulsars at high frequencies, since the radio fluxes of RRAT pulsars decreases with increasing frequency. 相似文献
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