硼酸盐水溶液结构及研究方法

硼酸盐水溶液中多聚硼酸盐阴离子的分布及其平衡十分复杂。综述了水溶液中硼酸盐的主要存在形式、化学平衡及其研究方法。重点介绍和评价了离子交换、电导/电势滴定、11B核磁共振(11B NMR)、红外(IR)、拉曼光谱(Raman)、质谱(MS)等方法及其研究结论。对硼酸盐溶液结构研究的新方法如计算机模拟和衍射法,尤其是X射线衍射法(XRD)进行了介绍和展望。     

Spectroscopy of Yamato 984028

Comprehensive spectroscopic characterization of interior and exterior chips of the lherzolitic shergottite Y-984028 has been performed using results from six techniques. Data from UV–visible–near-IR reflectance spectra, thermal (mid-IR) emission spectra, attenuated total reflectance (ATR) spectra, transmission FTIR spectra, Raman microprobe spectra, and Mössbauer spectra of whole rock and mineral separates from this meteorite are integrated and compared. Five of these analytical techniques accurately determined the ～Fo₆₅ composition of the olivine within ±10 mol%. Both transmission FTIR and ATR spectra show broad features near 3500 cm^?1 indicating the presence of OH/H₂O that does not arise from surface water adsorption. The brown color of the Y-984028 olivine is likely due to the presence of nanophase metallic iron particles (npFe⁰) dispersed throughout the olivine during a major shock event on Mars. Y-984028 olivine also contains a significant amount of Fe³⁺, but this cannot be distinguished from Fe³⁺ that is present in pyroxene and possibly clay minerals. This meteorite and the nakhlite MIL03346 are the two most oxidized of the SNC meteorites studied to date, with Fe³⁺ contents consistent with high-temperature equilibration near the QFM oxygen buffer.     

郯庐断裂西侧大井头钾镁煌斑岩中金刚石激光拉曼和红外光谱特征研究

大井头岩体为郯庐断裂带西侧首个发现的含金刚石钾镁煌斑岩。笔者对其中的金刚石进行了激光拉曼和傅里叶可变红外光谱研究。其激光拉曼和红外光谱特征研究表明,测试的6颗金刚石可分为1a型和Ⅰb型2类,部分Ⅰb型金刚石叠加有Ⅰa型金刚石所特有的1 175 cm-1或1 182 cm-1吸收谱峰。根据测试金刚石的外貌特征和Ⅰb型初生金刚石向1a型金刚石转换的机制,认为大井头钾镁煌斑岩中的金刚石并非岩浆结晶成因,而是金刚石于地幔中率先形成,其后被超深源岩浆携带至地表,应属地幔捕掳晶成因。结合大井头地区优越的构造地质条件、金刚石重砂矿物异常及多处钾质超基性岩、火山角砾岩体的出露,认为该地区有望成为鲁西地区第四金刚石原生矿带。     

A Raman Investigation on the Boron form Occurring in Salt Lake Brine during Evaporation

Boron resources are abundant in the Da Qaidam Salt Lake of the Qaidamu basin in China,which has generated significant attention due to the presence of polyborate species in brine from this lake. In this study,Raman spectroscopy was used to investigate the existing form of boron in brine during evaporation. MgO·2 B_2 O_3-H_2 O,MgO·2 B_2 O_3-MgCl_2-H_2 O,and MgO·2 B_2 O_3-MgSO_4~-H_2 O solutions were also studied to determine the influence of boron concentration,pH,and electrolytes on the borate speciation from brine. The mononborates B( OH)_3 and B( OH)_4~-were found to be the only forms present in natural salt lake brine. Brine evaporation promoted the formation of the polyborate anions B_3 O_3( OH)_4~-,B_5 O_6( OH)_4~-,and B_6 O_7( OH)_6~(2-)and also promoted the disappearance of the B( OH)_4~-ion from brine at boron concentrations of more than 11 g/L B_2 O_3. The pentaborate ion B_5 O_6( OH)_4~-was sensitive to the solution pH and appeared only at p H values less than 8. 0. Meanwhile,the hexaborate ion B_6 O_7( OH)_6~(2-)was observed to be more dependent on the electrolyte magnesium chloride due to its special properties,such as promoting boron accumulation,lowering solution pH,and also its strong affinity for water molecules,which were all beneficial for the polymerization of borate ions in brine. Interaction mechanisms between polyborate anions during evaporation are also proposed herein. ake; evaporation; polyborate species; interaction mechanism.     

Microstructure of NH4Cl-NH3-H2O system studied by ATR-FTIR, Raman and MD simulation

The solubilities of ammonium chloride in aqueous ammonia decreased first and then increased with increasing ammonia concentrations, but the mechanism of this phenomenon has not been clarified. In the present work, the ATR-FTIR and Raman spectroscopy were employed to investigate the corresponding mechanism. The spectra analysis was focused on the region between 2500 and 4000 cm-1. It was firstly discovered that the N-H???N hydrogen bonds between ammonium ions and ammonia molecule was mainly formed in the NH4Cl-NH3-H2O system with concentrations higher than 10% ammonia, but N-H???O hydrogen bonds between ammonium ions and water molecule took advantage in the system with lower ammonia concentrations. Correspondingly, the phenomena of hydrogen bonding redshift and blueshift was observed respectively compared in NH3?H2O solution. Moreover, the hydrogen bonding structure of the saturated solution was obtained by means of MD simulation. The present work provides some theoretical basis for the separation of ammonium potassium chloride.     

铁含量对白云石拉曼光谱特征的影响

白云石中Fe含量分析是研究白云石（岩）成因的重要手段,研究白云石中Fe含量与拉曼光谱之间的关系能够提供一种利用拉曼光谱原位测定白云石中Fe含量的潜在方法。本次研究应用显微共聚焦激光拉曼光谱仪对不同Fe含量的白云石进行了拉曼光谱分析,并对其拉曼光谱变化特征进行了研究。研究结果表明,相较于白云石,铁白云石各个拉曼特征峰均向低频方向偏移。白云石的拉曼特征峰位移与Fe含量呈明显的线性关系,随着Fe含量增加,白云石的各个拉曼特征峰位移均减小。相较于[CO3]2−基团内部振动特征峰（v1、v3和v4峰）,两个晶格振动特征峰（T峰和L峰）随Fe含量变化的偏移更为明显。研究认为,由于Fe2+的离子半径大于Mg2+,当Fe2+替代白云石晶格中的Mg2+后,晶格中金属-氧键平均键长变长、平均键能变弱,从而改变了金属-氧键和C-O键拉曼活性振动,致使拉曼特征峰向低频方向偏移。本次研究初步建立了基于拉曼光谱中L峰和v1峰的峰间距测定白云石中Fe含量的方法,与传统方法相比,该方法对样品要求较低,能够进行非破坏性测试。     

生态遥感新锐——轻小型无人机的应用

基于研究对象视角梳理轻小型无人机遥感手段在生态学研究中的应用现状,重点分析了无人机在不同生态对象应用的优势和局限：优势主要在于其能够高灵活性、高分辨率地获取各生态对象的数据,为较大规模的生态研究提供了便利。在农田生态系统应用中主要关注农田信息检测、自动化农作等方面,但在这方面的应用还比较单一,缺乏更深层更全面的系统化应用;在森林草地中主要关注植被结构参数提取、生物量反演等,在数据采集过程中应注意设备的稳定性避免对数据准确性造成影响;城市生态系统主要集中在城市环境监测和测绘方面,同时城市方面飞控政策尚待完善;水生生态系统主要关注水生动植物监测和潮间带观测等,大规模监测也对设备续航和数据标准化处理提出了要求;动物研究应用中主要关注动物迁徙规律、物种分布等方面,在监测过程中需注意不要对动物栖息造成干扰。总的来说,无人机应用局限主要在于其获取的数据处理尚未标准化,飞控政策尚未成熟和硬件续航等方面。在此基础上探讨了未来无人机遥感在生态学研究的应用趋势：随着无人机智能化的软硬件发展和云端生态大数据的建立,无人机数据的获取和处理将更加智慧化,多源的无人机遥感数据将会更好地服务于生态学研究。     

The association of poorly ordered graphite, coke and bitumens in greenschist facies rocks of the Poniklá Group, Lugicum, Czech Republic: the result of graphitization of various types of carbonaceous matter

Greenschist facies rocks of the Poniklá Group (Ordovician-Silurian), Czech Republic, contain several types of carbonaceous matter that differ in their morphology, texture, reflectance and Raman characteristics. The first type consists of large (up to 3 mm) irregularly bound particles of low reflectance (R_omin = 0.9%; R_omax = 5.6%). The area ratio of the 1585 cm^-1 to 1350 cm^-1 Raman peaks (1.08–1.17) indicates an intermediate degree of graphitization. The formation of this type of highly porous particle, displaying a texture reminiscent of regular or needle coke, is attributed to the thermal alteration of the amorphous (structureless) kerogen of the precursor sediments. The second type consists of lamellar particles up to 30 μm thick, which can be associated with the latter or can occur independently in white mica-rich laminae. This type is characterized by high bireflectance (R_omin = 0.6%; R_omax = 11.9%) and by lower ratios (0.70–0.82) of the Raman peak areas. These particles are interpreted as the product of solid-state, diffusion-controlled graphitization of a chemically homogeneous organic material, e.g. of graptolite periderms. The third type consists of isometric, up to 2 mm large, commonly fractured grains and fragments which mainly occur in quartz-rich laminae. In reflected light, the texture is either homogeneous or consists of various types of anisotropic mozaics. The Raman peak area ratios (0.75–1.14) indicate a highly variable degree of structural ordering. These particles are considered as the remains of metamorphosed bitumens, accumulated in the sandy laminae of the original sediments. The fourth type consists of small particles of carbonaceous matter (maximum length 25 μm, thickness 1-2 μm), which occur adjacent to crystal faces of white micas. This type is probably the product of epitaxial growth of graphite from the gaseous phase. The results of this work indicate that the differences in the degree of graphitization of the carbonaceous matter in low-grade metamorphosed rocks can be mainly related to the initial nature of the sedimentary organic matter and to its premetamorphic history.     

Archaeometric characterisation and origin of black coatings on prehistoric pottery

Black or dark grey vessel surfaces with characteristic metallic lustre are recognised from various archaeological contexts throughout Europe. This feature is commonly attributed to the application of graphite-bearing coatings onto ceramic vessels. However, recent experimental studies have shown that a very similar visual effect can alternatively be achieved by polishing and, subsequently, firing in a reducing atmosphere (so-called smudging). In this study, experimentally manufactured ceramics as well as samples of prehistoric ware (dated to the Neolithic Age, late Bronze Age and early Iron Age) have been analysed to find the distinguishing features between graphite-based and non-mineral black coatings. In the low-magnification BSE images the well-preserved graphite-coated surfaces are characterized by a distinctive spotty pattern with numerous dark grey angular fragments of monomineralic or nearly monomineralic metamorphic rocks scattered in the clay groundmass. Provided that polished thin sections are skilfully prepared, individual graphite plates can be easily recognized in the near-surface layer of the sherds using polarized reflected light microscopy. A relatively homogeneous appearance is typical of the low-magnification BSE images of surfaces coated by smudging. At higher magnifications, presence of blurred darkish stains (presumably organic-derived, as indicated by elevated levels of biogenic elements) is characteristic of this kind of non-mineral black coatings. SEM-EDS and optical microscopy have been supplemented by micro-Raman spectroscopy, which allows differentiation between various carbonaceous phases.