胡敏酸在高岭土上的吸附行为

研究了胡敏酸在高岭土上的吸附行为 ,并运用X衍射、红外光谱和热重等分析方法 ,对复合前后的高岭土进行分析。结果表明 ,连续洗涤 6次后 ,可获得稳定的胡敏酸高岭土复合体 ;胡敏酸在高岭土上的吸附符合Fruendlich吸附模式 ,Kf 为 0 .85 7;高岭土胡敏酸复合体的红外光谱出现了明显的C—H振动吸收峰 ;吸附行为主要表现为化学吸附 ,发生在铝的表面羟基吸附位上     

Lattice vibrational modes in synthetic tremolite-Sr-tremolite and tremolite-richterite solid solutions

Powder IR spectra of synthetic richterite-tremolite and Sr-tremolite-tremolite solid solutions were obtained in the spectral range between 1400 and 600?cm^?1. Under the consideration of the crystal structure and the Wykoff positions of the atoms in the primitive unit cell, the number, type and symmetry of vibrational modes were deduced. The space group of tremolite C_2h was used as the factor group leading to 16 theoretical stretching vibrations in the IR range caused by the Si₄O₁₁ ^∞-ribbon. The energy of the internal vibrations of the Si₄O₁₁ ^∞-ribbon is a function of the relative bond strengths and masses of nearby ions. For the amphiboles a one-mode behavior was observed for all the Si-O, Si-O-Si and O-Si-O stretching vibrations, indicating no clustering in the two solid solution series. In both solid solution series the vibrational energy of the stretching vibrations is a linear function of composition. In the system richterite-tremolite a shift of the stretching frequencies of the Si₄O₁₁ ^∞-ribbon over the whole compositional range of up to 30?cm^?1 was observed. In contrast, for Sr-tremolite-tremolite the maximum shift was only 5?cm^?1. These quite small band shifts allow the (Si₄O₁₁)^∞-ribbon to be treated as an isolated entity for factor group analysis. Nevertheless, by the two exchange mechanisms, Ca(M4)???Sr(M4) and □(A) Ca(M4)???Na(A)Na(M4), the FWHHs increased and the amplitudes decreased, indicating a slight distortion of the ribbon. For Sr-tremolite-tremolite only a linear expansion of the lattice was observed. In the series richterite-tremolite individual bond angles of the SiO₄ tetrahedra are additionally changed, causing the higher energy shift of the bands. The strongest and sharpest bands were observed for the end member tremolite. The one-mode behavior of the Si₄O₁₁-double chain indicates that there is no short-range order of Na/Ca and Ca/Sr at the M4 sites of these amphiboles.     

蓝宝石3310cm—1红外吸收峰的鉴定意义

本文对不同处理的蓝宝石及天然蓝宝石进行红外吸收光谱研究 ,结合蓝宝石的形成条件 ,发现 :(1)天然山东蓝宝石中普遍存在 3310cm- 1 的红外吸收峰 ,这与山东蓝宝石形成于还原环境有关 ;(2 )其他产地的蓝宝石是否存在 3310cm- 1 的红外吸收峰与其形成时的氧化还原条件有关 ;(3)经氧化热处理的蓝宝石中不存在 3310cm- 1 的红外吸收峰 ;(4 )扩散法处理的蓝宝石中是否存在 3310cm- 1 的红外吸收峰视其方法而定。因此 ,作者认为 :结合形成环境和处理方法 ,3310cm-     

Investigation of the Small-Scale Temperature and Density Fluctuations in Planetary Nebulae through the Use of the ISO Data

The problem of the ne and Te fluctuations in the planetary nebulae (PN) in a view of the ISO data was investigated. The fluxes in the OIII fine structure (FS) lines for a large sample of PNe were estimated. This revised version was published online in August 2006 with corrections to the Cover Date.     

AGB stars in the Magellanic Clouds

The stars that will be detectable in the Magellanic Clouds by the DENIS and 2MASS near infrared surveys are enumerated. All thermally-pulsing AGB stars will be observable in I, J, H and K, along with the top two magnitudes of both the early-AGB and the first giant branch. All carbon stars will be visible, and normal (N type) C stars will be easily distinguished by their large J-K colours. However, it will not be possible to separate faint, warm C stars from K and M stars using the photometry alone. Photometry of AGB stars in clusters will allow an accurate evaluation of the AGB tip luminosities as a function of initial mass. Random phase K magnitudes of LPVs and Cepheids should provide a better measure of the LMC tilt and distortions in the SMC. The K survey should turn up 100 to 150 objects undergoing superwind mass loss, these objects being OH/IR stars and the dust-enshrouded C star equivalents of OH/IR stars. It is shown that crowding should not be a problem even in the LMC bar.     

Current problems in star formation and infrared surveys

Star forming regions and young stellar objects are well known to be strong sources of infrared radiation. Such objects will be among the conspicous targets in the upcoming NIR surveys. Therefore, these surveys promise important new information on various unsolved questions concerning the star formation process. Among the problems where significant progress can be expected are the environmental effects on star formation, the derivation of star formation efficiencies and star formation rates, and all questions related to the fragmentation process and the initial mass function. Moreover, the NIR surveys may also help identifying new examples of protostars and PMS objects for follow-up investigations of their physical structure.     

The radiolysis of SO2 and H2S in water ice: Implications for the icy jovian satellites

Spectra of Europa, Ganymede, and Callisto reveal surfaces dominated by frozen water, hydrated materials, and minor amounts of SO₂, CO₂, and H₂O₂. These icy moons undergo significant bombardment by jovian magnetospheric radiation (protons, electrons, and sulfur and oxygen ions) which alters their surface compositions. In order to understand radiation-induced changes on icy moons, we have measured the mid-infrared spectra of 0.8 MeV proton-irradiated SO₂, H₂S, and H₂O-ice mixtures containing either SO₂ or H₂S. Samples with H₂O/SO₂ or H₂O/H₂S ratios in the 3-30 range have been irradiated at 86, 110, and 132 K, and the radiation half-lives of SO₂ and H₂S have been determined. New radiation products include the H₂S₂ molecule and HSO⁻₃, HSO⁻₄, and SO²⁻₄ ions, all with spectral features that make them candidates for future laboratory work and, perhaps, astronomical observations. Spectra of both unirradiated and irradiated ices have been recorded as a function of temperature, to examine thermal stability and phase changes. The formation of hydrated sulfuric acid in irradiated ice mixtures has been observed, along with the thermal evolution of hydrates to form pure sulfuric acid. These laboratory studies provide fundamental information on likely processes affecting the outer icy shells of Europa, Ganymede, and Callisto.     

A CLIMATOLOGY OF DEEP CONVECTION OVER SOUTH CHINA AND THE ADJACENT WATERS DURING SUMMER

Due to the higher temporal and spatial resolution and the better integrality of long-term satellite infrared(IR) Brightness Temperature(TBB) data,a climatology of deep convection during summer over South China and the adjacent waters is presented in this paper based on the 1-hourly infrared IR TBB data during June-August of 1996-2007(except 2004).The results show that the geographic distribution of deep convection denoted by TBB ≤-52℃ over South China and the adjacent waters are basically consistent with previous statistical results based on surface thunderstorm observations and low-orbit satellite lightning observations.The monthly,ten-day,five-day and diurnal variations of deep convection in this region are focused on in this paper.There are 5 active deep-convection areas in June-August.The monthly variations of the deep convection are closely associated with the large-scale atmospheric circulations.The deep convection over the land areas of South China is more active in June while that over the South China Sea is more active in July and August.The development of deep convection is prominently intermittent and its period is about 3 to 5 five-day periods.However,the deep convection over the coastal areas in South China remains more active during summer and has no apparent intermittence.The ten-day and five-day variations of deep convection show that there are different variations of deep convection over different areas in South China and the adjacent waters.The tendency of deep convection over the land areas of South China is negatively correlated with that over the South China Sea.The diurnal variations of deep convection show that the sea-land breeze,caused by the thermal differences between land and sea,and the mountain-valley breeze,caused by the thermal differences between mountains and plains or basins,cause deep convection to propagate from sea to land in the afternoon and from land to sea after midnight,and the convection over mountains propagates from mountains to plains after midnight.The different diurnal variations of deep convection over different underlying surfaces show that not only there are general mountainous,marine and multi-peak deep convection,but also there is longer-duration deep convection over coastal areas and other deep convection triggered and maintained by larger-scale weather systems in South China during summer.     

Saturn’s F ring grains: Aggregates made of crystalline water ice

We present models of the near-infrared (1-5 μm) spectra of Saturn’s F ring obtained by Cassini’s Visual and Infrared Mapping Spectrometer (VIMS) at ultra-high phase angles (177.4-178.5°). Modeling this spectrum constrains the size distribution, composition, and structure of F ring particles in the 0.1-100 μm size range. These spectra are very different from those obtained at lower phase angles; they lack the familiar 1.5 and 2 μm absorption bands, and the expected 3 μm water ice primary absorption appears as an unusually narrow dip at 2.87 μm. We have modeled these data using multiple approaches. First, we use a simple Mie scattering model to constrain the size distribution and composition of the particles. The Mie model allows us to understand the overall shapes of the spectra in terms of dominance by diffraction at these ultra-high phase angles, and also to demonstrate that the 2.87 μm dip is associated with the Christiansen frequency of water ice (where the real refractive index passes unity). Second, we use a combination of Mie scattering with Effective Medium Theory to probe the effect of porous (but structureless) particles on the overall shape of the spectrum and depth of the 2.87 μm band. Such simple models are not able to capture the shape of this absorption feature well. Finally, we model each particle as an aggregate of discrete monomers, using the Discrete Dipole Approximation (DDA) model, and find a better fit for the depth of the 2.87 μm feature. The DDA models imply a slightly different overall size distribution. We present a simple heuristic model which explains the differences between the Mie and DDA model results. We conclude that the F ring contains aggregate particles with a size distribution that is distinctly narrower than a typical power law, and that the particles are predominantly crystalline water ice.