Evolutionary status of the spectral variable BD + 48°1220 = IRAS 05040+4820

Based on high-resolution observations (R = 60 000 and 75 000), we have studied the optical spectral variability of the star BD + 48°1220, identified with the IR source IRAS 05040+4820. We have measured the equivalent widths of numerous absorption lines of neutral atoms and ions at wavelengths from 4500 Å to 6760 Å, as well as the corresponding radial velocities. We use model atmospheres to determine the effective temperature T _eff = 7900 K, surface gravity log g = 0.0, microturbulence velocity ξ _t = 6.0, and the abundances for 16 elements. The star’s metallicity differs little from the solar value: [Fe/H] = ?0.10 dex. The main peculiarity of the chemical composition of the star is a large helium excess, derived from the Hel λ 5876 Å absorption, [He/H] = +1.04, and the equally large oxygen excess, [O/Fe] = +0.72 dex. The carbon excess is small, [C/Fe] = +0.09 dex, and the ratio [C/O] < 1. We obtained an altered relation for the light-metal abundances: [Na/Fe] = +0.87 dex with [Mg/Fe] = ?0.31 dex. The barium abundance is low, [Ba/Fe] = ?0.84 dex. It is concluded that the selective separation of elements onto dust grains of the envelope is probably efficient. The radial velocity of the star measured from photospheric absorption lines over three years of observations varies in the interval V _⊙ = ?(7–15) km/s. Time-variable differential line shifts have been revealed. The entire set of available data (the luminosity M _v ≈ ?5 ^m , velocity V _lsr ≈ ?20 km/s, metallicity [Fe/H] = ?0.10, and peculiarities of the optical spectrum and chemical composition) confirms the status of BD + 48°1220 as a post-AGB star with He and O excesses belonging to the Galactic disk.     

Variability of the Blazar 1156+295 in 2005–2020

Astronomy Reports - We present and analyze the monitoring results of the blazar 1156+295 in radio, optical, and gamma ranges in 2005–2020. After a long period of relative quietness at the end...     

Solubility of the buffer assemblage pyrite + pyrrhotite + magnetite in NaCl solutions from 200 to 350°C

In the design of hydrothermal solubility studies it is important that the system be completely defined chemically. If the solubilities of minerals containing m metallic elements are to be determined in hydrothermal NaCl solutions, the phase rule requires that a total of m + 6 independent intensive parameters be controlled or measured in order to determine completely the system.In this study the solubility of the univariant assemblage pyrite + pyrrhotite + magnetite has been determined in vapor saturated hydrothermal solutions from 200 to 350°C for NaCl concentrations ranging from 0.0 to 5.0 molal. At any temperature, oxygen and sulfur fugacities were buffered by the chosen assemblage. System pH was determined from excess CO₂ partial pressures and computed ionic equilibria. Equilibrium constants were calculated by regression analysis of solubility data. The results show that more than 10 ppm of each mineral can dissolve in typical hydrothermal solutions under geologically realistic conditions. Solubilities were best represented by the species Fe²⁺ and FeCl⁺ at 200 and 250°C; Fe²⁺, FeCl⁺ and FeCl₂⁰ at 300°C; and Fe²⁺ and FeCl₂⁰ at 350°C. Ore deposition would occur by lowering temperature, diluting chloride concentration, or by raising pH through wall rock alteration reactions.     

Variations of the Blazar AO 0235+164 in 2006–2015

The results of optical, radio, and gamma-ray observations of the blazar AO 0235+16 are presented, including photometric (BV RIJHK) and polarimetric (R)monitoring carried out at St. Petersburg State University and the Central (Pulkovo) Astronomical Observatory in 2007–2015, 43 GHz Very Long Baseline Interferometry radio observations processed at Boston University, and a gamma-ray light curve based on observationswith the Fermi space observatory are presented. Two strong outbursts were detected. The relative spectral energy distributions of the variable components responsible for the outbursts are determined; these follow power laws, but with different spectral indices. The degree of polarization was high in both outbursts; only an average relationship between the brightness and polarization can be found. There was no time lag between the variations in the optical and gamma-ray, suggesting that the sources of the radiation in the optical and gamma-ray are located in the same region of the jet.     

Detection Statistics of Pulse Signals at Declinations from +42° to +52° at the Frequency 111 MHz

Astronomy Reports - A search for pulse signals was carried out in a new sky area included in the monitoring program for the search for pulsars and transients. Processing of several months data...     

Radio flux variations of the quasar J1159+2914 (S5 1156+295) in 2010–2013

Results of the observations of the blazar J1159+2914 (S1156+295) in 2010–2013 are reported. The observations were carried out on the RATAN-600 radio telescope (Special Astrophysical Observatory, Russian Academy of Sciences) at 4.85, 7.7, 11.1, and 21.7 GHz and the 32-m Zelenchuk and Badary radio telescopes of the Quasar-KVO Complex (Institute of Applied Astronomy, Russian Academy of Sciences) at 4.85 and 8.57 GHz. A flare peaked in August 2010, after which the flux density decreased monotonically at all studied frequencies. Variability on a timescale of 7 days was detected at 7.7 and 11.1 GHz near the flare maximum. The delay in the maximum at 7.7 GHz relative to the maximum at 11.1 GHz was 1.5 d, implying a Lorentz factor γ = 55 and angle of the jet to the line of sight θ ≈ 2° since mid-2011. Searches for intraday variability (IDV) were undertaken by the 32-m telescopes, mostly since mid-2011. Intraday variability was confidently detected only at the Badary station on November 10–11, 2012 at 4.85 GHz: the IDV timescale was τ _acf = 6 h, the modulation index was m = 1.4%, and the flux density of the variable component was S _var = 126 mJy.     

Optical variability of the blazar S4 0954+658 in 2008–2012

The results of multi-color photometric and polarization observations of the blazar S4 0954+658 carried out mainly in the Astronomical Institute of St. Petersburg State University and the Central Astronomical Observatory of the Russian Academy of Sciences in 2008–2012 are analyzed. Individual variable components that are responsible for the activity are distinguished; the power-law spectrum and high degree of polarization confirm that the emission is synchrotron radiation. Modeling the observed dependences between the parameters of the polarization and intensity is used to derive parameters of both the constant and the variable components of the radiation. The observed color variability (“the brighter, the bluer”) can be explained by the superposition of a red constant component and a bluer variable component with a constant relative spectral energy distribution.     

Experiment and Pitzer Model Prediction for the Solid + Liquid Equilibria of the Ternary System LiCl–CaCl2–H2O

正1 Introduction Lithium resources are widely distributed in the oilfield brine from the Nanyishan district in the Qaidam Basin(Fan et al.,2007).The investigation of the thermodynamics and phase diagram of the brine system is valuable in providing the theoretic foundation and scientific guidance in the comprehensive exploitation of the mixture salts effectively.Comprehensive     

应用VC+ +对MAPGIS进行二次开发

本介绍了用VC＋＋对MAPGIS进行二次开发的方法和基本函数以及软件开发实例。     

Haitaite-(La), LaU4+Fe3+2(Ti13Fe2+4Fe3+)Σ18O38, a New Member of the Crichtonite Group

Haitaite-(La), (La, Ce)(U4+, U6+, Fe2+)(Fe3+, Al)2(Ti, Fe2+, Fe3+)18O38, is a new member of the crichtonite group. It is named after the Haita Village in the Miyi County of Sichuan Province, China, where the mineral was discovered. The mineral occurs as black opaque centimeter-sized aggregates in the external contact zone between the Neoproterozoic (~800 Ma) alkali feldspar granite and the Mesoproterozoic (~1700 Ma) micaschist. In the studied sample, haitaite-(La) is associated with other minerals, including ilmenite, magnetite, rutile, zircon, brannerite and uraninite. The new mineral is a black, metallic phase and has a Mohs hardness of 6, with a density of 4.99 g/cm3 (calculated) and 5.03 g/cm3 (measured). Haitaite-(La) is opaque in transmitted light and grayish-white under reflected light, with a reflectivity between 22.5% and 16.42% in the 400–700 nm band (SiC, in the air). The compositions of the mineral were measured by EPMA, the U4+/U6+ ratio was determined by X-ray photoelectron spectroscopy and the Fe2+/Fe3+ ratio was determined by M?ssbauer spectroscopy. Haitaite-(La) is trigonal, belongs to R3ˉ and has unit-cell parameters a = 10.3678(5) ?, c = 20.8390(11) ?, V = 1939.9(2) ?3, Z = 3. The crystalline structure is composed of octahedra with 9 layers of close-packed octahedra (M1, M3, M4, M5), tetrahedra (M2) and contains large 12-coordinated M0 sites.     

Raman study of MgCr2O4–Fe2+Cr2O4 and MgCr2O4–MgFe2 3+O4 synthetic series: the effects of Fe2+ and Fe3+ on Raman shifts

Two synthetic series of spinels, MgCr₂O₄–Fe²⁺Cr₂O₄ and MgCr₂O₄–MgFe₂ ³⁺O₄ have been studied by Raman spectroscopy to investigate the effects of Fe²⁺ and Fe³⁺ on their structure. In the first case, where Fe²⁺ substitutes Mg within the tetrahedral site, there is a continuous and monotonic shift of the Raman modes A_1g and E_g toward lower wavenumbers with the increase of the chromite component into the spinel, while the F_2g modes remain nearly in the same position. In the second series, for low Mg-ferrite content, Fe³⁺ substitutes for Cr in the octahedral site; when the Mg-ferrite content nears 40 %, a drastic change in the Raman spectra occurs as Fe³⁺ starts entering the tetrahedral site as well, consequently pushing Mg to occupy the octahedral one. The Raman spectral region between 620 and 700 cm^?1 is associated to the octahedral site, where three peaks are present and it is possible to observe the Cr–Fe³⁺ substitution and the effects of order–disorder in the tetrahedral site. The spectral range at 500–620 cm^?1 region shows that there is a shift of modes toward lower values with the increase of the Mg-ferrite content. The peaks in the region at 200–500 cm^?1, when observed, show little or negligible Raman shift.     

Optical absorption investigation of Cr3+ ion-bearing minerals in the temperature range 77–797 K

The effect of raising temperature on spin-allowed dd-transitions of octahedral Cr³⁺ was studied for various point symmetries of the Cr³⁺-bearing structural sites, i.e. 3 m and 3 with inversion center in spinel and garnets, respectively, or 32, 3, 2 and 1, lacking the inversion centre, in beryl, corundum, diopside and topaz, respectively. For this purpose, crystals of Cr³⁺-bearing spinel, pyrope, andradite, grossular, uvarovite, emerald, ruby, diopside and topaz were analyzed by microprobe, oriented, and measured in polarized radiation (except for the cubic minerals) in the spectral range 30 000 to 11 100 cm^-1 and at temperatures between 77 and 797 K. The evaluation of the intensities, half widths, and energy positions of bands due to Cr³⁺-transitions derived from ⁴ A _2g ⁴ T _2g (F) and ⁴ T _1g (F) as well as of Dq- and B-values derived, had the following results:In all cases, red shift of the above bands and, hence, independent on the site symmetry of Cr³⁺, decreases in the Dq-values were obtained. The dependcies of Dq on T are nearly linear above room temperature and amount between -1.6% in topaz and -5.1% in pyrope in the temperature range studied. From this, values for the local thermal expansion of the Cr³⁺-centered octahedra, _loc, were derived on the basis of the R _M-0 ^-5 -proportionality of 10Dq. Such values are consistently higher than those obtained from X-ray refinements, a method averaging r_m-o for all the respective octahedral positions.     

Local structural relaxation around Co2+ along the hardystonite–Co-?kermanite melilite solid solution

Six pure compounds belonging to the hardystonite (Ca₂ZnSi₂O₇)–Co-?kermanite (Ca₂CoSi₂O₇) solid solution were investigated by the combined application of X-ray powder diffraction and electronic absorption spectroscopy. Structural refinements of the XRPD data revealed a negative excess volume of mixing due to the single isovalent substitution of Co for Zn in the tetrahedral site. In agreement with the diffraction data, deconvolution of the optical spectra showed a progressive decreasing of the crystal field strength parameter 10Dq moving toward the Co-?kermanite end-member, meaning that the local cobalt–oxygen bond distance, $ \langle {\text{Co}}{-}{\text{O}}\rangle^{\text{local}} $ , increased along the join with the amount of cobalt. The calculated structural relaxation coefficient around the fourfold coordinated Co²⁺ in the Ca₂(Zn_1?x Co _x )Si₂O₇ join was ε?=?0.69, very far from the one predicted by the Vegard’s law (ε?=?0) and at variance with ε?=?0.47 previously found for tetrahedrally coordinated Co²⁺ in gahnite–Co-aluminate spinel solid solution. This difference is consistent with the largest constraints existing on the spinel structure, based on cubic closest packing, compared to the more flexible layered melilite structure.     

Influence of cation distribution on the optical absorption spectra of Fe3+-bearing spinel s.s.–hercynite crystals: evidence for electron transitions in VIFe2+–VIFe3+ clusters

Flux-grown Fe³⁺-bearing spinel s.s.–hercynite solid-solution crystals, (Mg _1-y Fe²⁺ _y )Al₂O₄ (0 < y≤ 1), have been investigated by means of electron microprobe technique and Mössbauer and electronic spectroscopy. Obtained results show that different electronic processes cause intense optical absorption bands in the near-infrared spectral region. In addition to an electronic d–d transition in single-ion ^IVFe²⁺, observed at 5200 cm^?1, intense and broad bands at 9500 and 14 500 cm^?1 are assigned to exchange-coupled pair (ECP) and intervalence charge-transfer (IVCT) transitions in ^VI Fe ^{2+ VI} Fe³⁺clusters, respectively. The net linear extinction coefficients of these bands (α) were calibrated against Fe²⁺ and Fe³⁺ concentrations and site distributions previously defined by combined microchemical, Mössbauer, and XRD structural refinement data. The following expressions were obtained: where α is measured in cm^?1 and concentrations are expressed in mol?l^?1. The present results show that optical absorption spectroscopy may be used as a probe to obtain high spatial resolution (?～ 10 μm) information on Fe²⁺ ordering as well as on Fe³⁺ concentrations in minerals belonging to the spinel group.     

富含Na+ 、Ca2+、Al3+、Cr3+蒙脱石对垃圾渗滤液中有机物的吸附

由于层间含有高价态金属阳离子的蒙脱石对特定有机物的吸附能力可大大增强,故分别用层间含有Na+、Ca2+、Al3+和Cr3+的蒙脱石对垃圾渗滤液中的有机物进行吸附实验,研究它们吸附苯酚、二甲苯和COD的能力及离子形态对吸附效果的影响.结果表明,含高价金属阳离子的蒙脱石对苯酚和COD的吸附能力较高,吸附能力由小到大的顺序为Na+<Ca2+<Al3+<Cr3+蒙脱石;各种类型蒙脱石对二甲苯的吸附能力相对较低,并且没有一定的规律可循.并对氢键吸附机制进行了探讨.     

The influence of the Jahn–Teller effect at Fe<Superscript>2+</Superscript> on the structure of chromite at high pressure

The crystal structure of chromite FeCr₂O₄ was investigated to 13.7 GPa and ambient temperature with single-crystal X-ray diffraction techniques. The unit-cell parameter decreases continuously from 8.3832 (5) to 8.2398 (11) Å up to 11.8 GPa. A fit to the Birch–Murnaghan equation of state (EoS) based on the P–V data gives: K ₀ = 209 (13) GPa, K′ = 4.0 (fixed), and V ₀ = 588 (1) ų. The FeO₄ tetrahedra and CrO₆ octahedra are compressed isotropically with pressure with their Fe–O and Cr–O bond distances decreasing from 1.996 (6) to 1.949 (7) Å and from 1.997 (3) to 1.969 (7) Å, respectively. The tetrahedral site occupied by the Fe²⁺ cation is more compressible than the octahedral site occupied by the Cr³⁺ cation. The resulting EoS parameters for the tetrahedral and the octahedral sites are K ₀ = 147 (9) GPa, K′ = 4.0 (fixed), V ₀ = 4.07 (1) ų and K ₀ = 275 (24) GPa, K′ = 4.0 (fixed), V ₀ = 10.42 (2) ų, respectively. A discontinuous volume change is observed between 11.8 and 12.6 GPa. This change indicates a phase transition from a cubic (space group Fd-[`3]{\overline{3}} m) to a tetragonal structure (space group I4₁ /amd). At the phase transition boundary, the two Cr–O bonds parallel to the c-axis shorten from 1.969 (7) to 1.922 (17) Å and the other four Cr–O bonds parallel to the ab plane elongate from 1.969 (7) to 1.987 (9) Å. This anisotropic deformation of the octahedra leads to tetragonal compression of the unit cell along the c-axis. The angular distortion in the octahedron decreases continuously up to 13.7 GPa, whereas the distortion in the tetrahedron rises dramatically after the phase transition. At the pressure of the phase transition, the tetrahedral bond angles along the c-axis direction of the unit cell begin decreasing from 109.5° to 106.6 (7)°, which generates a “stretched” tetrahedral geometry. It is proposed that the Jahn–Teller effect at the tetrahedrally coordinated Fe²⁺ cation becomes active with compression and gives rise to the tetrahedral angular distortion, which in turn induces the cubic-to-tetragonal transition. A qualitative molecular orbital model is proposed to explain the origin and nature of the Jahn–Teller effect observed in this structure and its role in the pressure-induced phase transition.     

设计总承包+全过程项目管理(E+PMC)及设计院牵头的研发+工程总承包(R+EPC)的工程实践

<正>当前,随着工程建设投资的日益多元化,大量对建设领域并不熟悉的投资主体纷纷进入市场。然而,复杂的工程项目建设对业主的管控能力和专业性都提出了极高的要求。缺乏专业性的业主自行管理建设时,会面临很大的风险,并需建立和维持长期的项目管理班子,构建足够的全环节管控能力,这也必然会造成人力和物力的浪费。因此,寻求社会化、专业化的项目管理单位(PMC)和EPC工程总承包商,以提供全过程项目管理服务和EPC工程总承包服务就成了最佳选择。而作为长     

Forest biomass carbon dynamics (1980–2009) in western Himalaya in the context of REDD+ policy

Carbon emissions from forests have decreased in the past decade due to conservation efforts, however majority of carbon losses suffered in the past went unnoticed until the role of forests in mitigating climate change was realized. Forestry sector in developing countries is recognized as one of the largest and low cost mitigation options to address climate change. The present study was conducted to assess the multi-temporal biomass carbon mitigation in the temperate forests of western Himalaya using satellite (Landsat MSS, TM, ETM+) and forest inventory data. Forest type density mapping was done through on-screen visual interpretation of satellite data. After conducting preliminary survey in 2009, 45 quadrats (0.1 ha) were laid in six forest types for collecting field inventory data viz., diameter at breast height, tree height, slope and aspect. Biomass carbon (t ha^?1) was estimated for different forest types with different crown densities (open with 10–40% crown density and closed with >40%) using recommended regression equations, ratios and factors. A decreasing trend of carbon (145.13–134.87 mt) was observed over the period of time. Temporal biomass carbon dynamics was analyzed for REDD+ opportunities. The temporal variation of carbon observed was found to be more useful for claiming benefits under negative options (deforestation and forest degradation) of REDD+. The study doesn’t take actual conversions to CO₂ into account. However, the findings are useful in establishing baseline emissions through temporal carbon losses. Further, the study helps in identification of location specific socio-economic drivers of losses that can be used for appropriate mitigation interventions.     

高效厌氧+A/O+MBR+NF多级组合工艺处理某垃圾填埋场垃圾渗滤液

本项目采用厌氧+A/O+MBR+NF多级组合工艺处理某垃圾填埋场垃圾渗滤液,设计处理规模为300m3/d,出水水质可达到《生活垃圾填埋场污染控制标准》(GB16889-2008)中一般地区对渗滤液出水水质的要求。