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1.
As part of our study of the components of the hierarchic quadruple system ADS 11061, we acquired spectroscopic observations of the binary 40 Dra. Echelle spectra showing the separation of the components’ lines were obtained in the spectral range 3700–9200 Å. Effective temperatures and surface gravities were derived for the components from BV photometry and the hydrogen-line profiles. The components of the 40 Dra system have parameters close to T eff a = 6420 K, log g a = 4.17, T eff b = 6300 K, and log g b = 4.20. We find the microturbulence velocity in the component atmospheres to be V t = 2.6 km/s. The abundances of iron, carbon, nitrogen, and oxygen in the atmospheres of both components are estimated to be log N(Fe)a = 7.50, log N(Fe)b = 7.46, log N(C)a = 8.39, log N(C)b = 8.45, log N(N)a = 8.12, log(N)b = 8.15, log N(O)a = 8.77, log N(O)b = 8.74.  相似文献   

2.
An analysis of high-resolution CCD spectra of the giant 25 Mon, which shows signs of metallicity, and the normal giant HR 7389 is presented. The derived effective temperatures, gravitational accelerations, and microturbulence velocities are Teff = 6700 K, log g = 3.24, and ξ t = 3.1 km/s for 25 Mon and Teff = 6630 K, log g = 3.71, and ξ t = 2.6 km/s for HR 7389. The abundances (log ε) of nine elements are determined: carbon, nitrogen, oxygen, sodium, silicon, calcium, iron, nickel, and barium. The derived excess carbon abundances are 0.23 dex for 25 Mon and 0.16 dex for HR 7389. 25 Mon displays a modest (0.08 dex) oxygen excess, with the oxygen excess for HR 7389 being somewhat higher (0.15 dex). The nitrogen abundance is probably no lower than the solar value for both stars. The abundances of iron, sodium, calcium (for HR 7389), barium, and nickel exceed the solar values by 0.22–0.40 dex for both stars. The highest excess (0.62 dex) is exhibited by the calcium abundance for 25 Mon. Silicon displays a nearly solar abundance in both stars—small deficits of ?0.03 dex and ?0.07 dex for 25 Mon and HR 7389, respectively. No fundamental differences in the elemental abundances were found in the atmospheres of 25 Mon and HR 7389. Based on their Teff and log g values, as well as theoretical calculations, A. Claret estimated the masses, radii, luminosities, and ages of 25 Mon (M/M⊙ = 2.45, log(R/R⊙) = 0.79, log(L/L⊙) = 1.85, t = 5.3 × 108 yr) and HR 7389 (M/M⊙ = 2.36, log(R/R⊙) = 0.50, log(L/L⊙) = 1.24, t = 4.6 × 108 yr), and also of the stars 20 Peg (M/M⊙ = 2.36, log(R/R⊙) = 0.73, log(L/L⊙) = 1.79, t = 4.9 × 108 yr) and 30 LMi (M/M⊙ = 2.47, log(R/R⊙) = 0.73, log(L/L⊙) = 1.88, t = 4.8 × 108 yr) studied by the author earlier.  相似文献   

3.
A technique for IR spectroscopic determination of the total nitrogen content N S in the form of A-and B 1-defects is suggested. It provides for the computer processing and decomposition of IR spectra into constituent bands, calculation of the total absorption band area S N and individual areas S A and S B1 and their normalization with respect to the total area of the diamond intrinsic absorption S 0, with the normalization coefficients K S , K A , and K B1 being calculated. Based on the analysis of the IR spectra of 60 octahedral diamond crystals from the Mir and Yubileinaya pipes (Sakha-Yakutiya), the empirical functions N S = 911.85 K S 0.9919 ppm (R 2 = 0.9859), N A = 1185.6 K A 1.1511 ppm (R 2 = 0.8703), and N B1 = 911.85 K S 0.9919 ? 1185.6 K A 1.1511 ppm have been defined.  相似文献   

4.
The crystal structure of the unstable mineral alumoklyuchevskite K3Cu3AlO2(SO4)4 [monoclinic, I2, a = 18.772(7), b = 4.967(2), c = 18.468(7) Å, β = 101.66(1)°, V = 1686(1) Å] was refined to R 1 = 0.131 for 2450 unique reflections with F ≥ 4σF hkl. The structure is based on oxocentered tetrahedrons (OAlCu 3 7+ ) linked into chains via edges. Each chain is surrounded by SO4 tetrahedrons forming a structural complex. Each complex is elongated along the b axis. This type of crystal structure was also found in other fumarole minerals of the Great Tolbachik Fissure Eruption (GTFE, Kamchatka Peninsula, Russia, 1975–1976), klyuchevskite, K3Cu3Fe3+O2(SO4)4; and piypite, K2Cu2O(SO4)2.  相似文献   

5.
ROSAT spectra of 11 supersoft X-ray sources are approximated with theoretical spectra obtained in LTE models for the atmospheres of hot white dwarfs with line blanketing. The confidence intervals of parameters derived from these approximations—Teff, log, g, NH, and R2/d2—are determined. The results are compared with predictions for a model with stable/recurrent thermonuclear burning on the white-dwarf surface.  相似文献   

6.
Single-crystal study of the structure (R = 0.0268) was performed for garyansellite from Rapid Creek, Yukon, Canada. The mineral is orthorhombic, Pbna, a = 9.44738(18), b = 9.85976(19), c = 8.14154(18) Å, V = 758.38(3) Å3, Z = 4. An idealized formula of garyansellite is Mg2Fe3+(PO4)2(OH) · 2H2O. Structurally the mineral is close to other members of the phosphoferrite–reddingite group. The structure contains layers of chains of M(2)O4(OH)(H2O) octahedra which share edges to form dimers and connected by common edges with isolated from each other M(1)O4(H2O)2 octahedra. The neighboring chains are connected to the layer through the common vertices of M(2) octahedra and octaahedral layers are linked through PO4 tetrahedra.  相似文献   

7.
The crystal structure of a new compound, (H3O)[(UO2)(SeO4)(SeO2OH)] (monoclinic, P21/n, a = 8.6682(19), b = 10.6545(16), c = 9.846(2) Å, β = 97.881(17)°, V = 900.7(3) Å3), was solved by direct methods and refined to R 1 = 0.050. The structure contains two symmetrically different Se atoms. The Se1 site is coordinated by three O atoms as is characteristic of Se4+ cations. The Se2 site is coordinated by four O atoms and forms selenate anion SeO 4 2? . The structure is based on selenite-selenate sheets [(UO2)(SeO4)(SeO2OH)]? linked by the interlayer H3O? ions. The sheets are parallel to (101). The structure is compared to that of schmiederite, Pb2Cu2(SeO3)(SeO4)(OH)4.  相似文献   

8.
The crystal structures of synthetic K-dravite [XKYMg 3 Z Al 6 T Si6O18(BO3) 3 V (OH) 3 W (OH)], dravite [XNaYMg 3 Z Al 6 T Si6O18(BO3) 3 V (OH) 3 W (OH)], oxy-uvite [XCaYMg 3 Z Al 6 T Si6O18(BO3) 3 V (OH) 3 W O], and magnesio-foitite [X?Y(Mg2Al)ZAl 6 T Si6O18(BO3) 3 V (OH) 3 W (OH)] are investigated by polarized Raman spectroscopy, single-crystal structure refinement (SREF), and powder X-ray diffraction. The use of compositionally simple tourmalines characterized by electron microprobe analysis facilitates the determination of site occupancy in the SREF and band assignment in the Raman spectra. The synthesized K-dravite, oxy-uvite, and magnesio-foitite have significant Mg–Al disorder between their octahedral sites indicated by their respective average 〈Y–O〉 and 〈Z–O〉 bond lengths. The Y- and Z-site compositions of oxy-uvite (YMg1.52Al1.48(10) and ZAl4.90Mg1.10(15)) and magnesio-foitite (YAl1.62Mg1.38(18) and ZAl4.92Mg1.08(24)) are refined from the electron densities at each site. The Mg–Al ratio of the Y and Z sites is also determined from the relative integrated peak intensities of the Raman bands in the O–H stretching vibrational range (3250–3850 cm?1), producing values in good agreement with the SREF data. The unit cell volume of tourmaline increases from magnesio-foitite (1558.4(3) Å3) to dravite (1569.5(4)–1571.7(3) Å3) to oxy-uvite (1572.4(2) Å3) to K-dravite (1588.1(2) Å3), mainly due to lengthening of the crystallographic c-axis. The increase in the size of the X-site coordination polyhedron from dravite (Na) to K-dravite (K) is accommodated locally in the crystal structure, resulting in the shortening of the neighboring O1–H1 bond. In oxy-uvite, Ca2+ is locally associated with a deprotonated W (O1) site, whereas vacant X sites are neighbored by protonated W (O1) sites. Increasing the size of the X-site-occupying ion does not detectably affect bonding between the other sites; however, the higher charge of Ca and the deprotonated W (O1) site in oxy-uvite are correlated to changes in the lattice vibration Raman spectrum (100–1200 cm?1), particularly for bands assigned to the T 6O18 ring. The Raman spectrum of magnesio-foitite shows significant deviations from those of K-dravite, dravite, and oxy-uvite in both the lattice and O–H stretching vibrational ranges (100–1200 and 3250–3850 cm?1, respectively). The vacant X site is correlated with long- and short-range changes in the crystal structure, i.e., deformation of the T 6O18 ring and lengthening of the O1–H1 and O3–H3 bonds. However, X-site vacancies in K-dravite, dravite, and oxy-uvite result only in the lengthening of the neighboring O1–H1 bond and do not result in identifiable changes in the lattice-bonding environment.  相似文献   

9.
Theoretical analysis, calculations, and comparison with the results of observations in Lake Baikal, Lake Tanganyika, and the World Ocean are performed for the vertical stability E and the Brunt-Väisäla frequency N in the form of N 2 with regard to all components (at the constant temperature T and the salinity S, the common adiabatic form at T, S Const). The adiabatic stability E ad and the Väisäla frequency N in the form of N ad 2 are always positive; at a change from the inverse to the direct temperature stratification, they have deep minimums reaching 10?16 m?1 and 10?15 s?2 and less; the minimums have the form of a special point, a reversal point of the first kind called a “cusp.” The reality of these reversal points is confirmed by the analysis of the investigation procedure, comparison with the results of previous theoretical (Sherstyankin, et al., 2007), and experimental (observations in Baikal, Shimaraev et al., 1994) works. The features of vertical profiles of E ad , E andN ad 2 , N 2, as well as the layers where the Brunt-Väisäla frequency is less than the inertial frequency, are studied. The analysis with regard to all components of the stability E ad and the Brunt-Väisäla frequency N makes a great contribution to understanding of mixing processes in theoretical and experimental investigations; it is valid in all reservoirs of the Earth with inverse and direct temperature stratification, including Lake Baikal, Lake Tanganyika, and the World Ocean.  相似文献   

10.
The crystal structure of a new compound [Mg(H2O)4(SeO4)]2(H2O) (monoclinic, P2 1/a, a = 7.2549(12), b = 20.059(5), c = 10.3934(17) Å, β = 101.989(13), V = 1479.5(5) Å3) has been solved by direct methods and refined to R 1 = 0.059 for 2577 observed reflections with |F hkl | ≥ 4σ|F hkl |. The structure consists of [Mg(H2O)4(SeO4)]0 chains formed by alternating corner-sharing Mg octahedrons and (SeO4)2? tetrahedrons. O atoms of Mg octahedrons that are shared with selenate tetrahedrons are in a trans orientation. The heteropoly-hedral octahedral-tetrahedral chains are parallel to the c axis and undulate within the (010) plane. The adjacent chains are linked by hydrogen bonds involving H2O molecules not bound with M2+ cations.  相似文献   

11.
We have obtained high-accuracy photoelectric measurements of ES Lac, an eclipsing binary with an elliptical orbit (B9III + B9III; P = 4.459d, e = 0.198) in 1985–2004 at the Sternberg Astronomical Institute’s Tien Shan High-Altitude Observatory. Our detailed analysis of the 19-year uniform series of measurements has yielded the first photometric elements for this system, as well as a self-consistent set of physical and geometrical parameters for the binary. The virtually identical components (M 1 = M 2 = 3.0 M ⊙; R 1 = R 2 = 4.12 R ⊙) are appreciably separated from the main sequence, and are located on the giant branch: their age is t = (3.5 ± 0.2) × 108 yrs. An analysis of our observations together with previously published times of minima has enabled a considerable refinement of the period of the apsidal motion, U = 355 ± 20 years, and a first determination of the apsidal parameter reflecting the radial density distributions for the components stars: k 2 obs = 0.00213(18). This value is in a good agreement with the value expected theoretically for current evolutionary models of such stars: k 2 th = 0.00257(15).  相似文献   

12.
A new potassium uranyl selenate compound K(UO2)(SeO4)(OH)(H2O) has been synthesized for the first time using the technique of evaporation from water solution. Its crystal structure has been solved by direct methods (monoclinic, P21/c,a = 8.0413(9) Å, b = 8.0362(9) Å, c = 11.6032(14) Å, β = 106.925(2)°, V = 717.34(14) Å3) and refined to R 1 = 0.0319 (wR 2 = 0.0824) for 1285 reflections with |F 0| > 4σ F . The structure consists of [(UO2(SeO4)(OH)(H2O)]? chains extending along axis b. In the chains, the uranyl pentagonal bipyramids are linked via bridged hydroxyl anions and tetrahedral oxoanions [SeO4]2?. Potassium ions are situated between these chains. No chains of that type have been observed in uranyl compounds earlier, but they had been detected in the structures of butlerite, parabutlerite, uklonskovite, fibroferrite, and a number of synthetic compounds.  相似文献   

13.
The first high-accuracy CCDUBV RI light curves for the recently discovered eclipsing system V1176 Cas (P = 6 . d 33, V = 11 . m 1) have been obtained. A photometric solution for the light curves and physical characteristics of the component stars are derived. The orbital eccentricity is negligible, e = 0.009; both components have physical parameters similar to the Sun, but they are younger and may have an overabundance of metals. The orientation of the orbital ellipse and the low eccentricity make studies of the apsidal motion difficult. Nevertheless, the high accuracy of the available measurements of the timings of minima has enabled derivation of an upper limit for the rate of apsidal rotation, which agrees with a theoretical estimate of this effect.  相似文献   

14.
The solubility of Gd2Ti2O7 ceramic in acidic solutions (HCl and HClO4) was studied at 250°C and saturation vapor pressure within pH 2.5–5.2. The dissolution process occurs mainly via two reactions: 0.5 Gd2Ti2O7(cr) + 3H+ = Gd3+ + TiO2(cr) + 1.5 H2O at pH < 3 and 0.5Gd2Ti2O7(cr) + H+ + 0.5H2O = Gd(OH) 2 + TiO2(cr) at pH 3–5. The thermodynamic equilibrium constants were calculated at the 0.95 confidence level as log K (1) o = 4.12 ± 0.47; = ?0.97 ± 0.16 at 250°C. It was shown that Gd3+ undergoes hydrolysis in solutions with pH > 3, and the species Gd(OH) 2 + dominates up to at least pH 5. At pH < 3, Gd occurs in solutions as Gd3+. The second constant of Gd3+ hydrolysis was determined at 250°C as K o = ?5.09 ± 0.5, and the thermodynamic characteristics of the initial Gd2Ti2O7 solid phase were determined: S 298.15 o = 251.4 J/(mol K) and ΔfG 298.15 o = ?3630 ± 10 kJ/mol.  相似文献   

15.
We have analyzed the orbital light curve of the X-ray nova XTE J1118+480 in a “disk + hot line” model based on three-dimensional gas-dynamical computations of gas flows in interacting binary systems. As a result, we have been able to derive reliable parameters for the system: i = 80 ?4 +4 degrees, MBH = 7.1 ?0.1 +0.5 M⊙, M opt = 0.39 ?0.07 +0.15 M⊙.  相似文献   

16.
A new mineral, droninoite, was found in a fragment of a weathered Dronino iron meteorite (which fell near the village of Dronino, Kasimov district, Ryazan oblast, Russia) as dark green to brown fine-grained (the size of single grains is not larger than 1 μm) segregations up to 0.15 × 1 × 1 mm in size associated with taenite, violarite, troilite, chromite, goethite, lepidocrocite, nickelbischofite, and amorphous Fe3+ hydroxides. The mineral was named after its type locality. Aggregates of droninoite are earthy and soft; the Mohs hardness is 1–1.5. The calculated density is 2.857 g/cm3. Under a microscope, droninoite is dark gray-green and nonpleochroic. The mean (cooperative for fine-grained aggregate) refractive index is 1.72(1). The IR spectrum indicates the absence of S O 4 2? and C O 3 2? anions. Chemical composition (electron microprobe, partition of total iron into Fe2+ and Fe3+ made on the basis of the ratio (Ni + Fe2+): Fe3+ = 3: 1; water is calculated from the difference) is as follows, wt %: 36.45 NiO, 12.15 FeO, 17.55 Fe2O3, 23.78 H2O, 13.01 Cl, ?O=Cl2 ?2.94, total is 100.00. The empirical formula (Z = 6) is Ni2.16Fe 0.75 2+ Fe 0.97 3+ Cl1.62(OH)7.10 · 2.28H2O. The simplified formula is Ni3Fe3+Cl(OH)8 · 2H2O. Droninoite is trigonal, space group R \(\bar 3\) m, R3m, or R32; a = 6.206(2), c = 46.184(18) Å; V = 1540.4(8) Å3. The strong reflections in the X-ray powder diffraction pattern [d, Å (I, %) (hkl)] are 7.76(100)(006), 3.88(40)(0.0.12), 2.64(25)(202, 024), 2.32(20)(0.2.10), 1.965(0.2.16). The holotype specimen is deposited at the Fersman Mineralogical Museum, Russian Academy of Sciences, Moscow, registration number 3676/1.  相似文献   

17.
The paper reports new findings of avdoninite from deposits of active fumaroles in the Second Scoria Cone at the Northern Breach of the Great Fissure Tolbachik Eruption, Tolbachik Volcano, Kamchatka Peninsula, Russia. The crystal structure of the mineral has been determined for the first time, which has allowed reliable determination of its space group and unit cell dimensions, refinement of its formula K2Cu5-Cl8(OH)4 · 2H2O, and correct indexing of its X-ray powder diffraction pattern. Avdoninite is monoclinic, space group P21/c, a = 11.592(2), b = 6.5509(11), c = 11.745(2) Å, β = 91.104(6)°, V = 891.8(3) Å3, Z = 2. The crystal structure of this mineral has been determined on a single crystal R 1 [F > 4σ (F)] = 0.063. It is based on sheets of copper–oxo-chloride complexes [Cu5Cl8(OH)4]2– parallel to (100). The K+ cation and H2O molecules are interlayers.  相似文献   

18.
Large-scale melting of the Earth’s early mantle under the effect of global impact processes was accompanied by the generation of volatiles, which concentration was mainly controlled by the interaction of main N, C, O, and H gas-forming elements with silicate and metallic melts at low oxygen fugacity (fO2), which predominated during metallic segregation and self-oxidation of magma ocean. The paper considers the application of Raman and IR (infrared) Fourier spectroscopy for revealing the mechanisms of simultaneous dissolution and relative contents of N, C, O, and H in glasses, which represent the quench products of reduced model FeO–Na2O–Al2O3–SiO2 melts after experiments at 4 GPa, 1550°C, and fO2 1.5–3 orders of magnitude below the oxygen fugacity of the iron—wustite buffer equilibrium (fO2(IW)). Such fO2 values correspond to those inferred for the origin and evolution of magma ocean. It was established that the silicate melt contains complexes with N–H bonds (NH3, NH 2 + , NH 2 - ), N2, H2, and CH4 molecules, as well as oxidized hydrogen species (OH– hydroxyl and molecular water H2O). Spectral characteristics of the glasses indicate significant influence of fO2 on the N–C–O–H proportion in the melt. They are expressed in a sharp decrease of NH 2 + , NH 2 - (O–NH2), OH–, H2O, and CH4 and simultaneous increase of NH 2 - (≡Si–NH2) and NH3 with decreasing fO2. As a result, NH3 molecules become the dominant nitrogen compounds among N–C–H components in the melt at fO2 two orders of magnitude below fO2(IW), whereas molecular СН4 prevails at higher fO2. The noteworthy feature of the redox reactions in the melt is stability of the ОН– groups and molecular water, in spite of the sufficiently low fO2. Our study shows that the composition of reduced magmatic gases transferred to the planet surface has been significantly modified under conditions of self-oxidation of mantle and magma ocean.  相似文献   

19.
Kamarizaite, a new mineral species, has been identified in the dump of the Kamariza Mine, Lavrion mining district, Attica Region, Greece, in association with goethite, scorodite, and jarosite. It was named after type locality. Kamarizaite occurs as fine-grained monomineralic aggregates (up to 3 cm across) composed of platy crystals up to 1 μm in size and submicron kidney-shaped segregations. The new mineral is yellow to beige, with light yellow streak. The Mohs hardness is about 3. No cleavage is observed. The density measured by hydrostatic weighing is 3.16(1) g/cm3, and the calculated density is 3.12 g/cm3. The wavenumbers of absorption bands in the IR spectrum of kamarizaite are (cm?1; s is strong band, w is weak band): 3552, 3315s, 3115, 1650w, 1620w, 1089, 911s, 888s, 870, 835s, 808s, 614w, 540, 500, 478, 429. According to TG and IR data, complete dehydration and dehydroxylation in vacuum (with a weight loss of 15.3(1)%) occurs in the temperature range 110–420°C. Mössbauer data indicate that all iron in kamarizaite is octahedrally coordinated Fe3+. Kamarizaite is optically biaxial, positive: n min = 1.825, n max = 1.835, n mean = 1.83(1) (for a fine-grained aggregate). The chemical composition of kamarizaite (electron microprobe, average of four point analyses) is as follows, wt %: 0.35 CaO, 41.78 Fe2O3, 39.89 As2O5, 1.49 SO3, 15.3 H2O (from TG data); the total is 98.81. The empirical formula calculated on the basis of (AsO4,SO4)2 is Ca0.03Fe 2.86 3+ (AsO4)1.90(SO4)0.10(OH)2.74 · 3.27H2O. The idealized formula is Fe 3 3+ (AsO4)2(OH)3 · 3H2O. Kamarizaite is an arsenate analogue of orthorhombic tinticite, space group Pccm, Pcc2, Pcmm, Pcm21, or Pc2m; a = 21.32(1), b = 13.666(6), c =15.80(1) Å, V= 4603.29(5) Å3, Z= 16. The strongest reflections of the X-ray powder diffraction pattern [\(\bar d\), Å (I, %) (hkl)] are: 6.61 (37) (112, 120), 5.85 (52) (311), 3.947 (100) (004, 032, 511), 3.396 (37) (133, 431), 3.332 (60) (314), 3.085 (58) (621, 414, 324). The type material of kamarizaite is deposited in the Mineralogical Collection of Technische Universität Bergakademie Freiberg, Germany, inventory number 82199.  相似文献   

20.
The crystal structure of a new compound Zn(SeO4)(H2O)2 (orthorhombic, Pbca, a = 9.0411(13), b = 10.246(2), c = 10.3318(15) Å, V = 957.1(3) Å3) has been solved by direct methods and refined to R 1 = 0.033 on the basis of 1076 observed reflections with |F hkl | ≥ 4σ|F hkl |. The structure contains one independent Zn2+ cation coordinated by two water molecules and four oxygen atoms of selenate group. The only independent (SeO4)2? tetrahedral oxoanion is tetradentate, sharing its corners with four adjacent [Zn2+O2(H2O4)]2+ octahedrons. The structure can be described as consisting of heteropolyhedral sheets parallel to the (001) plane and linked together into a three-dimensional network. The compound belongs to the variscite structure type and is the first structurally characterized selenate of this group.  相似文献   

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