西北地区侏罗纪煤显微组分结构的Micro-FTIR研究

我国西北地区侏罗纪煤资源丰富,揭示该地区煤显微组分的微观化学结构特征是对其进行合理高效利用的必要前提。采用透射式显微傅里叶红外光谱技术(Micro-FTIR)对西北地区侏罗纪煤中主要显微组分——镜质体、丝质体、半丝质体的分子结构特征进行了分析。结果表明,相对于丝质体,镜质体和半丝质体的脂肪氢相对含量较高,而芳香氢、CO相对含量较低,半丝质体的脂肪氢相对含量高于丝质体的这一分子结构特点是导致西北地区侏罗纪煤虽富含惰质组却具有较高反应性的一个重要原因;相对于强还原型煤,弱还原型煤镜质体、半丝质体和丝质体皆具有较低的脂肪氢相对含量及较高的CO相对含量,成煤过程中不同强度的氧化作用是造成煤具有不同还原类型的原因之一。     

显微红外光谱填图法示踪中国三个产地的天然钻石中氮杂质的非均匀生长

钻石产地特征研究在了解地幔演化及遏制国际冲突钻石非法交易等方面具有重要意义,采用傅里叶变换显微红外光谱技术对采自中国三个商业性产地的14片天然IaAB型钻石进行了系统的面扫描分析,根据显微红外光谱谱图定量计算出钻石中的氮含量(1 616个红外测试数据)并进行填图示踪。结果表明,钻石生长过程中氮的含量和聚集度不断变化,且成核阶段氮含量可高于或低于其他生长阶段,不同生长阶段氮杂质含量不具有单向变化规律,显示钻石生长过程中地幔流体碳和氮存在复杂的交换,不同产地钻石中氮含量频率分布及NB%/N(T)特征存在一定的区域性差异,与跳点法红外光谱测试相比,面扫描法填图能更直观和连续的示踪钻石生长过程中氮杂质的不均匀生长。     

Thermally excited multiplet states in macerals separated from bituminous coal

Electron paramagnetic resonance searches of thermally excited multiplet states in macerals, exinite, vitrinite, and inertinite of Polish medium-rank coal (85.6 wt% C), were performed. Numerical analysis of lineshape indicates a multicomponent structure of the EPR spectra of macerals heated at 300 degrees and 650 degrees C. EPR spectra of exinite and vitrinite are a superposition of broad Gauss, broad Lorentz (Lorentz 1), and narrow Lorentz (Lorentz 3) lines. Two narrow Lorentz (Lorentz 2 and Lorentz 3) lines were observed in the resonance absorption curves of inertinite. The influence of the measuring temperature (100-300 K) on the EPR lines of the macerals was also studied. The experimentally obtained temperature dependence of the EPR line intensities were fitted by the theoretical functions characteristic for paramagnetic centers with ground doublet state (S = 12) and paramagnetic centers with thermally excited triplet (S = 1) and quadruplet (S = 32) states. Thermally excited multiplet states were found in exinite and vitrinite. Both paramagnetic centers with doublet ground state (S = 12) and paramagnetic centers with thermally excited states, probably quadruplet states (S = 32), exist in the group of paramagnetic centers of exinite and vitrinite with the broad Lorentz 1 lines. Intensities (I) of the broad Gauss and the narrow Lorentz 3 lines of exinite and vitrinite changes with temperature according to the Curie law (I = C/T). The existence of thermally excited multiplet states was not stated for inertinite. The two groups of paramagnetic centers of inertinite with Lorentz 2 and Lorentz 3 lines obey the Curie law. Copyright 2000 Academic Press.     

Influence of microwave power on EPR spectra of coal macerals

The paper contains a numerical analysis of the electron paramagnetic resonance (EPR) spectra of coal macerals (exinite, vitrinite, inertinite) obtained from Polish medium-rank coal (85.6 wt% C). We determine the lineshapes and the parameters of the component lines, i.e., the intensities and linewidths. As a result, we find that the EPR spectra of the studied macerals are superpositions of broad Gaussian, broad Lorentzian 1 and narrow Lorentzian 3 lines for vitrinite and exinite and two narrow Lorentzian 2 and Lorentzian 3 lines for inertinite. The influence of microwave power on the component lines of the EPR spectrum is studied. A comparison of the results obtained at 223 and 293 K shows that the EPR lines at both temperatures saturate at the same microwave power. It also indicates similar changes of the linewidths with changes of microwave power at both temperatures, a slight increase with increasing microwave power.     

Investigation of precipitator ash from two sub-bituminous coals

Iron-57 Mössbauer spectra of the precipitator ash from two South Australian coals have allowed the identification of five iron containing phases, with extensive aluminium substitution for iron. Some effects of variation in the flame temperature were observed, but the analysis did not explain differences in the fouling characteristics of the coals.     

湖南扬子地台砂矿金刚石的红外、拉曼特征及指示意义

产于湖南沅水地区的十颗砂矿金刚石的红外光谱和拉曼光谱的研究结果表明：湖南砂矿金刚石多为I_aAB型,且往往表现为A型氮相对富集;金刚石中的氮含量介于38.30～840.67 μg·g-1之间,且不同金刚石晶体中氮含量差别极大;金刚石在地幔中的存储时间介于0.043～3.315 Ga之间,不同的样品在地幔中的存储时间相差较大,且最长存储时间(3.315 Ga)要大于湘鄂黔桂毗邻区最老岩体的年龄(3.285 Ga);湖南砂矿金刚石在其形成过程中经历过较为显著的环境变化,且菱形十二面体金刚石晶体的形成深度大于八面体金刚石晶体。     

镁合金阳极氧化膜腐蚀特性的红外显微成像分析

采用显微红外成像技术对镁合金阳极氧化膜表面的腐蚀特性进行了研究。镁合金在7.3 Wt% Na₂SO₄溶液中浸泡后,表面氧化层中的部分MgO逐渐转化为Mg(OH)₂,进而发生溶解和脱落,使得镁合金失去保护作用。当浸泡时间达到2 h时,显微红外成像结果表明阳极氧化膜中Mg(OH)₂的红外吸收信号最强,Mg(OH)₂的含量最多。而4 h后Mg(OH)₂的红外吸收信号开始减弱,Mg(OH)₂开始减少,镁合金不断被腐蚀。氧化膜中另一成分Al₂O₃随浸泡时间的显微红外成像信息与Mg(OH)₂的变化规律相同。采用电化学阻抗谱技术对阳极氧化膜的阻抗进行测试,其阻抗随时间的变化特点基本符合氧化膜腐蚀规律。本研究对于镁合金阳极氧化膜的表征具有很好的指导作用和推广应用价值。     

扬子克拉通西部砂矿型刻面状金刚石多晶的显微红外光谱研究及意义

扬子克拉通西部刻面状金刚石多晶的微区显微红外光谱研究结果表明,多晶以IaAB型为主,其中的氮含量变化较大,介于25.70～358.35 μg·g-1之间,且同一多晶的不同晶粒中的氮含量有明显差异。金刚石中的“A氮心→B氮心”聚集转变不完全,且B%集中在40%左右,未见C氮心;多晶不是在金刚石的成核阶段所形成的,而是在各个金刚石晶粒形成后在地幔储藏期间聚集在一起的。其形成环境较华北克拉通东部的山东蒙阴刻面状金刚石多晶更为复杂;多晶极可能形成于地幔深部160～180 km的范围内,达到扬子克拉通的核部深度,接近于岩石圈底部,为地幔深源成因;多晶中的sp2杂化C—H键的存在有利于片晶氮的形成,其浓度一般要高于sp3杂化C—H键的浓度。     

原位显微红外法检测热胁迫对荒漠植物刺叶墙藓质膜透性的影响

利用显微红外光谱法研究了不同生境下的刺叶墙藓质膜结构及其热胁迫耐性机理。从酯酰基、碳氢化合物红外吸收区域分析表明,刺叶墙藓野生叶片通过加快组织内部碳氢化合物合成速度,减少质膜渗透性,减轻高温对质膜胁迫损伤;室内培养的原丝体和新叶不能及时对热胁迫产生影响。     

Phase states of methane in fossil coals

NMR measurements have revealed that methane can exist in coal samples in the state of solid solution rather than only adsorbed gas, opening new ways to prevention of gas dynamic accidents in underground coal mines and true estimation of coalbed methane resources.Understanding molecular structure of coal constituents and forms of methane occurrence in coal is the only way of extracting safely either coal or methane. We had studied nuclear magnetic resonance lines in various coals at room or low temperatures and have found that there exist three species of methane molecules differing in molecular mobility. Based on estimated diffusion parameters, these species were attributed to free methane, adsorbed methane, and solid solution of methane in crystalline coal substance. While first two phases are well known and can be analyzed by many different techniques, the last one hardly can be studied by methods other than NMR, resulting in inadequate estimations of methane resources.     

Toward characterization of the aerosol optical properties over Loess Plateau of Northwestern China

Aerosol optical properties were obtained from a CIMEL sunphotometer of the Aerosol Robotic Network at the Semi-Arid Climate and Environment Observatory of Lanzhou University (SACOL). SACOL is located over the Loess Plateau of the Northwestern China. The observed data are analyzed for the period of August 2006-October 2008. We find that aerosol optical depths (AODs) have a pronounced annual cycle, with a maximum dust aerosol loading during the spring. The 2-year average values of AOD, Ångström exponent (α), and water vapor path (WVP) along with their standard deviation (in parenthesis) are 0.35 (0.21), 0.93 (0.34), and 0.77 cm (0.52 cm), respectively. The probability distributions of these quantities all have one modal value, which are 0.3, 1.1, and 0.5 cm, respectively. There is a notable feature in the relationship between daily averaged AOD and Ångström exponent: a wide range of α corresponding to moderate to low aerosol optical depths (<0.8). There is no significant correlation between daily averaged WVP and AOD. However the daily averaged Ångström exponent and WVP show a significant positive correlation, indicating that the smaller aerosol particles present when the WVP is large. Variations of the retrieved aerosol volume size distributions are mainly associated with the changes in the concentration of the coarse aerosol fraction. The geometric mean radii for the fine and coarse aerosols are 0.18 μm (±0.03 μm), and 2.53 μm (±0.25 μm), respectively. The spectral dependences of the single scattering albedos are different between the dusty and non-dusty conditions. In the presence of dust, the SSAs increase slightly with wavelength. When dust is not a major component, the corresponding values decrease with wavelength.     

Mössbauer study of the effect of acidic treatment on iron minerals during the demineralization of coals

Mössbauer spectroscopy was used to determine the iron-containing minerals that remained in two different Spanish subbituminous coals after acidic treatments. Spectra were taken before and after treatments of both coals with HCl and HCl followed by HF. Pyrite, jarosite and Fe²⁺-clay were the main iron mineral constituents of the untreated samples. After the treatments significant changes in the relative concentration of these species were noticed. The weakness of the used demineralization procedures is discussed.     

57Fe NGR studies on three-stage hydroliquefaction of coals

Iron Mössbauer spectroscopy has been performed on liquefaction residues of two different French coals. In a three-stage liquefaction of high volatile bituminous coal (Freyming), without an added catalyst, the coal pyrite is not entirely converted into pyrrhotites, whereas in the presence of an added catalyst, coal pyrite is totally transformed into more dispersed pyrrhotites than those from the sample without an added catalyst; furthermore, the whole added catalyst precursor is reduced into pyrrhotites. In the case of liquefaction of subbituminous coal (Gardanne), full conversion of coal pyrite into pyrrhotites (even without an added catalyst) occurs. In addition, in the presence of the added catalyst, besides pyrrhotites, FeS is evidenced. When molybdenum-iron oxide is added as a catalyst precursor, no mixed Fe?Mo phase is detected.     

Stability and electronic structure of InN nanotubes from first-principles study

The stability and electronic structure of hypothetical InN nanotubes were studied by first-principles density functional theory. It was found that the strain energies of InN nanotubes are smaller than those of carbon nanotubes of the same radius. Single-wall zigzag InN nanotubes were found to be semiconductors with a direct band gap while the armchair counterparts have an indirect band gap. The band gaps of nanotubes decrease with increasing diameter, similar to the case of carbon nanotubes.     

新疆吐哈盆地侏罗纪煤生烃模式的红外光谱分析

应用石英小玻管生烃热模拟实验和傅里叶变换红外光谱技术(FTIR),对吐哈盆地柯柯亚地区J_1b煤层煤样在不同热模拟温度下干酪根化学结构的变化特征进行了研究。结合煤样的显微组分镜下统计结果及红外吸收峰和相应的红外参数随温度变化的信息,初步确定了柯柯亚地区侏罗纪藻烛煤的生烃特征和模式。本区煤样以基质镜质体为主,同时含有一定量的藻类体和大量的小孢子体,是一种良好的生油气源岩。随着热模拟温度的升高,干酪根中芳香核的侧链不断脱落,活化能较低的含氧官能团和脂肪结构逐渐被分离出去,生烃潜力减小。这一生烃过程始于200 ℃左右,并在约350 ℃处达到高峰,至500 ℃已进行得比较完全。另一方面,当温度达到500 ℃时,干酪根开始有石墨化倾向,芳香核发生缩聚并逐渐密集排列,在600 ℃时比较明显。     

煤岩变质变形作用的谱学研究

为了探讨不同变质程度煤在不同变形机制和变形强度影响下的结构成分演化,该文对淮北煤田经历不同变质变形作用的构造煤样品进行了傅里叶变换红外光谱(FTIR)和激光Raman光谱的测试和分析.FTIR显示,变质和变形作用对大分子结构的降解和缩聚过程有着不同程度的影响;激光Raman光谱显示,变形作用导致大分子结构中次生结构缺陷的产生,变质作用对次生结构缺陷和芳族总量也有一定的影响.综合研究表明:韧性变形将应力作用转换成应变能,对降解和缩聚产生明显的影响,而脆性变形将应力作用转换成热能,促进降解的进行,对缩聚作用的影响较小.低变质阶段煤岩以降解作用为主,高变质阶段则以缩聚作用为主.在变质变形作用的影响下,脱落的小分子优先补充嵌入大分子结构的次生结构缺陷中或残留的芳环缩聚形成芳族结构,从而提高煤岩结构的稳定性,且韧性变形比脆性变形更容易导致次生结构缺陷的形成.     

Calorimetric study on the electronic structure in UP-US system

The heat capacity of UP_1?xS_x (x = 0.0, 0.1, 0.2, 0.4, 0.6, 0.8, 1.0) has been measured from 80 to 670 K by laser-flash calorimetry. All samples exhibit an anomaly corresponding to the magnetic transition. The magnetic transition temperatures determined are in good agreement with literature values. UP_0.4S_0.6 shows an additional small peak at 86 K below T_c. It has been derived that the US-rich ferromagnetically ordered state should be divided into two phases in terms of the direction of the moments. Above 250 K, the heat capacities of all samples increase monotonically with temperature and are well represented in the form of C_p= 6R + AT ? BT^?2. The conduction band structure has been derived from the high-temperature linear term and has been compared with that in literature. It has been suggested that the magnetically ordering behavior such as the direction of the moments would be closely correlated with the band structure.     

Analysis of trace elements in different three region coals in Erzurum (Turkey): a study using EDXRF

Analysis by energy dispersive X-ray fluorescence (EDXRF) spectroscopy of A?kale, Balkaya and Sütkans coal in Erzurum (Turkey) has been carried out for the determination of their elemental composition, using an annular and radioisotope source. The characteristic K X-rays of the different elements were detected with Si(Li) and Ge(Li) detectors. The analysis were performed on coal samples and the results were compared.     

A study of the level structure in Fe from the (d, p) reaction on Fe

The reaction ⁵⁶Fe(d, p)⁵⁷Fe is investigated at 12 MeV using the Aldermaston multi-channel magnetic spectrograph. The angular distributions of protons leading to various states in ⁵⁷Fe upto an excitation of 6.7 MeV are measured over an angular range 5°–175°. The data are analysed with the distorted wave Born approximation calculations; a satisfactory agreement is found in most cases upto about 100°. Spin, parity and the spectroscopic factors for various states are obtained and the positions of the single-quasiparticle energies determined. The results are compared with those for the isotonic nuclei ⁵⁵Cr and ⁵⁹Ni and with the pairing theory.