High resolution spectral features of a series of aromatic hydrocarbons and BrO: Potential interferences in atmospheric OH-measurements

Naphthalene (C₁₀H₈), several other hydrocarbons, mostly derivates of naphthalene, and bromine oxide (BrO) were analyzed for narrow band (0.01 nm) absorption lines in the wavelength range between 307.7 and 308.3 nm to study their potential impact on OH radical measurements by differential absorption spectroscopy.Only naphthalene showed narrow band absorption lines in this wavelength region. From nine naphthalene lines the differential absorption cross-section was determined.The strongest naphthalene line at 308.002 nm is close to the Q ₁(2) OH line, but about a factor of 200 weaker (=(65.2±15.3)×10^-20 cm²/molec). The corresponding detection limit for naphthalene is about 15 ppt. We re-evaluated some spectra of our OH measurement campaign in July 1987 with respect to naphthalene and obtained an upper limit of 30 ppt for its concentration.BrO was recorded in the larger wavelength interval between 307.7 and 308.7 nm. Structured absorptions were only observed at wavelengths above 308.2 nm and no significant structures were found in the vicinity of the Q ₁(2) and Q ₁(3) OH lines.     

The single-crystal,polarized-light,FTIR spectrum of stoppaniite,the Fe analogue of beryl

We report here a single-crystal polarized-light study of stoppaniite, ideally (Fe,Al,Mg)₄(Be₆Si₁₂O₃₆)(H₂O)₂(Na,□), from Capranica (Viterbo). Polarized-light FTIR spectra were collected on an oriented (hk0) section, doubly polished to 15 μm. The spectrum shows two main bands at 3,660 and 3,595 cm⁻¹; the former is strongly polarized for E ⊥c, while the latter is polarized for E //c. A sharp and very intense band at 1,620 cm⁻¹, plus minor features at 4,000 and 3,228 cm⁻¹ are also polarized for E //c. On the basis of literature data and considering the pleochroic behavior of the absorptions, the 3,660 cm⁻¹ band is assigned to the ν₃ stretching mode and the 1,620 cm⁻¹ (associated with an overtone 2*ν₂ at 3,230 cm⁻¹) band to the ν₂ bending mode of “type II” water molecules within the structural channels of the studied beryl. The sharp band at 3,595 cm⁻¹ is not associated with a corresponding ν₂ bending mode; thus it is assigned to the stretching vibration of O–H groups in the sample. The minor 4,000 cm⁻¹ feature can be assigned to the combination of the O–H bond parallel to c with a low-frequency metal-oxygen mode such as the Na–O stretching mode. The present results suggest that the interpretation of the FTIR spectrum of Na-rich beryl needs to be carefully reconsidered.     

三种方法测试岩溶水样氢氧同位素的对比研究

通过高温热转换元素-同位素比值质谱法（TC/EA-IRMS）、多用途气体制备仪-同位素比值质谱法（GasbenchⅡ-IRMS）以及激光光谱法对岩溶水样进行对比检测,其结果显示:对于氢同位素,TC/EA-IRMS的精密度达到0.3 ‰,激光光谱法的精密度达到0.1 ‰,均优于GasbenchⅡ-IRMS的精密度1.4 ‰;对于氧同位素,GasbenchⅡ-IRMS的精密度达到0.02 ‰,激光光谱法的精密度达到0.04 ‰,优于TC/EA-IRMS的精密度0.16 ‰。使用激光光谱法测定岩溶水样的氢氧同位素,所需要的样品量少,精密度高,能够满足岩溶区样品的高精度测试要求。      

傅立叶红外光谱技术在翡翠研究中的应用

基于透射光谱的差异，用傅立叶红外光谱研究翡翠的矿物组成；分析硬玉、霓石、霓辉石和透辉石等主要矿物，以天然翡翠的特征红外光谱为依据，鉴别市售翡翠的真伪和类别（Ａ、Ｂ货）；利用红外显微镜作微区透射光谱，鉴别通常难以鉴别的有裂缝及裂缝填充物的翡翠（Ｂ货），提出了准确的无损鉴别翡翠的方法。     

The proportions and variations of the light absorption coefficients of major ocean color components in the East China Sea

The East China Sea (ECS),one of the largest continental seas,has dynamic hydrology and complex optical characteristics that make ocean color remote-sensing retrieval difficult.The distributions and proportions of the light absorption coefficients of major ocean color components based on two large-scale investigations in the ECS are presented,showing these features in typical summer and winter seasons.The absorption coefficient a CDOM,a NAP and a phy of colored dissolved organic matter,non-algal particle,and pigment of phytoplankton show a decreasing trend from the coast to the outer shelf.According to the a CDOM distribution at 440 nm,the Changjiang River plume shows an abnormal southeastward transport.An extremely high a NAP value patch at 440 nm is present in the middle coast.The chlorophyll-a-specific phytoplankton pigment absorption (a phy) is much higher in winter than in summer,which may cause serious underestimated results when applying the averaged a phy into remote-sensing algorithms for chlorophyll concentration retrieval.The importance of phytoplankton size was evident in outer shelf waters.The absorption of a CDOM (440) is a dominant component accounting for over half of the total seawater absorption in summer.The a NAP (440) accounts for 64% of the absorption of the ECS coastal area in winter.     

"三软煤层"电磁波吸收特征分析

通过对梁家煤矿两个工作面的坑透试验研究,获得了“三软煤层”的电磁波吸收系数β;应用ＣＴ技术处理得到了工作面吸收色谱图,分析了“三软煤层裂隙、构造的吸收异常特征,取得了较好的地质效果。     

短波红外光谱矿物测量技术在普朗斑岩铜矿区热液蚀变矿物填图中的应用

利用便携式短波红外光谱测量仪（PIMA）在云南普朗斑岩铜矿区开展了短波红外光谱测量工作,通过系统的野外数据采集,获得了研究区蚀变矿物组合及主要蚀变矿物的分布,并建立了普朗斑岩铜矿区蚀变矿物分带模式。在此基础上,建立了斑岩铜矿床找矿模型,该模型对普朗铜矿区及其外围的找矿工作具有积极的指导意义。     

华南地区新石器早中期动物骨中羟磷灰石的污染鉴别及机制——以广西桂林甑皮岩遗址为例

了解古代人（动物）骨羟磷灰石的污染,是对其开展C、O稳定同位素分析以揭示其食物来源和栖息环境的前提条件。目前,我国在此方面开展的研究较少,华南地区尚无报道,由此导致我们对此区域人群生存方式的变迁以及农业的产生与扩散等一些重要考古学问题,仍缺乏深入的了解。本文以广西桂林甑皮岩洞穴遗址（新石器早中期）出土的20例动物骨为研究对象,以10例现代骨为参照,对以上原始样品以及预处理后的样品进行了红外光谱分析,并对预处理后的样品进行了C、O稳定同位素分析,以期实现骨羟磷灰石的污染鉴别和探讨其机制。根据已发表数据和本研究10例现代骨的红外光谱及其指标（IRSF、CO₃/PO₄、FW85%）,未经化学处理前的原始样品中,3例样品检测出明显的外源污染（方解石）,剩余17例原始样品中仅余3例为未受污染样品。经预处理后,含方解石样品（n=3）红外谱图显示,其结构内仍有方解石残存;剩余17例不含方解石的样品中,12例样品的红外指标皆已符合现有标准（IRSF≤4.2和CO₃/PO₄≤0.6）,样品可用数量显著提升。20例骨羟磷灰石的C、O稳定同位素分析进一步显示,去污染样品与污染样品的δ¹³C和δ¹⁸O值存在明显差异,污染样品的同位素数据更多反映了埋藏环境对其的影响。骨羟磷灰石的污染机制可能主要与华南地区特有的石灰岩地质环境密切相关。由此,进一步完善华南地区出土骨样的预处理方法并挑选出未受污染的样品,是今后开展稳定同位素分析的必经之路。

     

Researches on the stability of porphyra-334 solution and its influence factors

1　Introduction　Ultravioletradiationisahighlyactivecomponentofsolarspectrum .Ultravioletradiationhasdetrimentaleffectsonlivingthingsexposedtosunlight ,includingthedestructionofDNA ,proteinsandothermolecules(Harm ,1980 ) ,inhibitionofphotosynthesisandgrow…     

Insights into oxygen-cation bonding in fresnoite-type structures from O <Emphasis Type="Italic">K</Emphasis>- and Ti <Emphasis Type="Italic">L</Emphasis><Subscript>23</Subscript>-electron energy-loss spectra and ab initio calculations of the electronic structure

O K- and Ti L₂₃-core-loss spectra of fresnoite Ba₂TiSi₂O₈ (BTS) and Sr₂TiSi₂O₈ (STS), which is isotypic to BTS, have been measured by electron energy-loss spectroscopy (EELS). The energy-loss near-edge structures (ELNES) of the O K edge have been identified on the basis of theoretical simulations and interpretations of the X-ray absorption near-edge structures (XANES), which have been modelled in the framework of self-consistent full multiple-scattering (FMS) theory using FEFF8. Herewith, the K-absorption spectra of oxygen (E) and the local partial electron density of states (DOS) of all atoms have been calculated. For BTS, the observed spectral features in the O K-edge spectra are interpreted in terms of mixing between the central O p and neighbouring Ba 5d and 4f, Si 3p and 3d, and Ti 3d orbitals. The observed differences in the O K-edge spectra for STS and BTS can mainly be attributed to three properties: (1) The lack of high local partial Sr unoccupied DOS with 4f symmetry near the Fermi level compared to the high Ba 4f unoccupied DOS results in differences of overlapping O 2p – cation orbitals. (2) The differences in the ionic radii of Sr and Ba result in a larger unit cell for BTS and, thus, in larger oxygen-cation bonding distances. (3) In comparison to STS, the strength of the incommensurate 2-D structural modulation is significantly weaker in BTS, i.e. distortions of coordination polyhedra occur to a much lesser extent. All these effects alter the oxygen-cation hybridization and, hence, result in a variation of the O 1s p transition and consequently of the O K-edge spectral shape. The observed peak broadening in Ti L₂₃ ELNES of STS compared to BTS is correlated with strong displacive modulations hosted in STS.