Zircon SHRIMP age of Mesoarchaean meta-argilloarenaceous rock in the Anshan area and its geological significance

In order to better understand the early continental evolution of the Anshan area, one of the typical Precambrian distribution areas of the North China Craton, the geochronology and REE composition of the zircons from the meta-argillo-arenaceous rock occurred as enclave in 3.1 Ga Lishan trondhjemite are studied by using SHRIMP II ion microprobe. It is indicated that the Paleoarchaean is a very important continental formation period in the Anshan area and 3.2 Ga can be regarded as the boundary between the Paleoarchaean and Mesoarchaean.     

Extraction of lithium from GSJ rock reference samples and determination of their lithium isotopic compositions

Li was extracted completely from the Geological Survey of Japan (GSJ) rock reference samples by HF-HC1 decomposition and separated from other alkali metal ions by cation exchange chromatography. The degree of Li isotope fractionation during the preparations of samples for mass spectrometry for Li isotopic ratio measurements was, therefore, negligible. The isotopic compositions of Li extracted from the GSJ samples were measured by double-filament surface ionization mass spectrometry. The permil (%.) deviation, δ⁷Li, of the ⁷Li-to-⁶Li ratio of one of the GSJ samples (JR-1) from that of the Li isotope standard, IRM-016, was +3.9%., with a 95% confidence limit of 0.7%. The δ⁷Li values of the 16 GSJ samples varied in the range −2.5 to +6.4%.. These data are probably the first such data obtained for the GSJ rock samples. No clear dependence of the δ⁷Li value on the kind of rock was observed.     

不同方法对西藏林芝野生核桃油的提取及脂肪酸成分分析

分别采用超临界流体萃取法、索氏抽提法、超声波提取法从西藏林芝地区野生核桃中提取核桃油,并采用气相色谱-质谱法分析了核桃油的脂肪酸组成.结果表明,3种提取方法核桃油得率均在57%以上,核桃油主要脂肪酸含量为亚油酸62.54%、油酸18.93%、亚麻酸7.27%、棕榈酸5.36%、花生四烯酸4.11%、硬脂酸1.78%.其...     

电热原子吸收光谱法测定恐龙化石及其围岩中的铅

电热原子吸收光谱分析法(ETAAS)灵敏度高、操作简便，是测定痕量铅的常用分析方法之一。铅及其化合物易挥发，在热解预处理阶段损失严重。对于某些样品，基体干扰较为复杂，需要选择合适的化学改进剂，如硝酸镁、磷酸、硫脲、磷酸氢二铵、磷酸二氢铵、钯盐等。现有许多测定铅     

Magmatism and deformation times of the Xidatan rock series, East Kunlun Mountains

The Xidatan rock series consist of mylonite, gneiss and granite. The U-Pb age showsthat the granite was formed at 206 Ma, and the ~(40)Ar/~(39)Ar ages of the biotite display that the my-lonite was formed at 145 Ma when the Xidatan ductile shear zone occurred. At about 110-100 Mathe Xidatan Fault reactivated again. As a result, the biotite and muscovite of Xidatan rock seriesopened their argon isotope system.     

电感耦合等离子体质谱法测定岩石中47种元素的不确定度评定

采用封闭酸溶电感耦合等离子体质谱(ICP-MS)法测定岩石样品,分别对47种元素的测量结果不确定度进行评定。通过分析测试方法和测量条件,得到测量结果的不确定度主要由样品称量、样品溶液定容和样品溶液中元素浓度测量引入。在实验室质控条件下,对各不确定度分量进行评定和计算,其中随机因素导致的不确定度采用期间精密度试验综合评价,即采用A类方法评定。共完成了16个岩石国家标准物质(GBW 07103~GBW 07123)47种元素测量结果的不确定度合成,并参照GB/T 6379.2-2004,建立了含量w与扩展不确定度U之间的关系模型,运用这一关系模型可得到测量结果的不确定度估计值,只要测量过程本身或所使用的设备未变化,就不需要再重复进行不确定度评估。     

Raman scattering study of polyaminopropylsiloxane and its compounds for characterization of 3-aminopropylsilane-modified silica gel. Utility of the CH2 rock and skeletal stretch modes

 The Raman scattering spectra for polyaminopropylsiloxane (poly-APS) samples in the solid state and in aqueous solution and for the related compounds, γ-aminobutyric acid (GABA) and its hydrochloride salt (GABA ⋅ HCl), have been examined in the CH₂ rock and skeletal stretch region. The Raman spectrum of the solid poly-APS sample may be accounted for by direct combination of the Raman spectra for GABA and GABA ⋅ HCl, whose crystal structures have been elucidated by a single-crystal X-ray diffraction study, suggesting that the APS segments of poly-APS in the solid state are in a conformationally ordered state. It has also been found that the Raman spectra of the solid and aqueous poly-APS samples in this region are useful for diagnosing the conformations of APS moieties bound onto the surface of silica gel. Received: 18 September 1996 Accepted: 2 December 1996     

On the area of feasible solutions and its reduction by the complementarity theorem

Multivariate curve resolution techniques in chemometrics allow to uncover the pure component information of mixed spectroscopic data. However, the so-called rotational ambiguity is a difficult hurdle in solving this factorization problem. The aim of this paper is to combine two powerful methodological approaches in order to solve the factorization problem successfully. The first approach is the simultaneous representation of all feasible nonnegative solutions in the area of feasible solutions (AFS) and the second approach is the complementarity theorem. This theorem allows to formulate serious restrictions on the factors under partial knowledge of certain pure component spectra or pure component concentration profiles.     

On the planarity and resonance effect of tetraphenylporphyren and its metallocomplexes

Based on Lennard-Jones potential and resonance effect calculations it has been demonstrated that in solution tetraphenylporphyrin assumes a structure closer to coplanar by 17° from that in the solid state. In the case of metalloporphyrin the tendency towards coplanarity is even greater, about 40°. The minimum in the energy curve is of the same order of magnitude as reported values of free energy of activation for the phenyl rotation.     

Multielement analysis of green coffee and its possible use for the determination of origin

Using instrumental neutron activation analysis (INAA), graphite furnace atomic absorption spectrometry (GFAAS), flame atomic absorption spectrometry (FAAS) and combustion elemental analysis, green coffees of the Arabica species produced in crop year 1987/88 in Colombia, Costa Rica, Cuba, El Salvador, Mexico, Nicaragua, Panamá and Papua New Guinea were analysed for the elements Ba, Br, C, Ca, Co, Cr, Cu, Cs, Fe, H, K, La, Mg, Mn, N, Na, Rb, Sc, Sr and Zn. In accordance with the concentrations determined, the elements could be ranked into five groups: Sc (sub-ppb level); Br, Co, Cr, Cs and La (ppb level); Ba, Cu, Fe, Mn, Na, Rb, Sr and Zn (ppm level); Ca and Mg (%o level); and C, H, K and N (% level). On the basis of the results obtained, an attempt was made to establish the origin of the green coffee via its elemental composition. Among the investigated elements, manganese was found to be best suited as an indicator for this purpose. However, the elements C, Co, Cs, Na and Rb proved to be of interest too.     

Evolution of the composition and structure of PAN carbon fiber during preoxidation

Using scanning electronic microscope, X-ray diffraction analysis, PYR-GCMS and IR etc., we studied the evolving process of the composition and structure of PAN carbon fiber during preoxidation. In the initial stage of preoxidation, PAN filament tows disappear and become semi-thaw. At first, reactions happen between the copolymers and esters disappear. The molecules annularly crosslink and the index of cyclation slowly increases. It is easy to fix the structure and form defects during the initial and the medium stages, which are most reactive. More traction is advised in these stages to minimize the structural deficiencies. In the medium stage of preoxidation, the fiber was reshaped into new sheet stacks and gradually changed to sheet sectors, and this structure tends to be stable in the final stage. Induced by acid and ester copolymer, PAN fiber forms a very stable cycle structure in the final stage. Besides, monomer, dimmer and trimer obviously decrease. In the final stage of the preoxidation, there exi     

An Empiric Linear Formula between the Internal Tetrahedron Symmetric Stretch Frequency and the Al Content in the Framework of KL Molecular Sieves

Since 1960's zeolite molecular sieves materials have been widely used in catalysis, adsorption, separation, host-guest chemistry and supramolecular science. During the research and application, the framework compositions of zeolite molecular sieves materials usually have to be determined, especially when the framework compositions are modified. Based on X-ray diffraction (XRD) peak positions and infrared (IR) spectroscopy frequencies, some empiric linear relationships have been reported t…     

稠油催化裂解前后咔唑类化合物的变化及其催化降黏机理的研究

在稠油族组成分离中,采用低毒试剂正己烷、二氯甲烷、无水乙醇及其混合溶剂,将反应前后已除去沥青质的稠油分离为饱和烃、芳烃和含氮化合物。优化并确立了各步分离条件,用GC-MS对各组分进行检测,了解水热催化裂解降黏前后各组分的变化,剖析了胶质中咔唑类化合物的变化。并结合¹HNMR、元素分析等分析手段,证明稠油经水热催化裂解反应后,重质组分中的含氮组分发生了变化,生成了部分咔唑类化合物, 同时,重质组分的组成和结构也发生了一定程度的改变,其超分子结构在一定程度上遭到破坏,生成二环、三环低环数芳烃和小分子量直链烃。这些变化使得稠油黏度降低。
     

广东省高州石鼓地区土壤硒分布特征及影响因素

富硒土壤是一种稀缺的土壤资源,具有重要的农业经济价值。以每1 km 8~16个点的表层(0~20 cm)、10条剖面的深层(100~220 cm)土壤以及6件岩石样品数据对广东省高州市石鼓地区硒分布特征及影响因素进行研究。结果表明,石鼓地区表层土壤以高硒为主,高硒面积达59.06%,适量硒土壤面积占40.94%,没有硒缺乏和硒过剩区域。深层土壤在硒含量适量区随深度变化不大,而在高硒区域硒富集于浅表层约60 cm处。表层土壤高硒含量位于北西侧及中部第四系冲积平原区,其次为北东部、中部新近系盆地相含油含煤地层,在南部白垩系河湖相砂泥岩硒含量基本呈自然状态―弱富集特征。土壤硒含量与土壤p H之间的关系不大,而与成土母质和有机质含量有关,富有机质的细粒土壤更有利于硒的富集。     

大别山北缘暨邻区中新生代砂岩稀土元素的地球化学特征及对源岩的制约

肥西地区侏罗纪防虎山组、园筒山组和早白垩世周公山组稀土元素具有如下特征: ∑REE为157 μg·g-1,δEu为0.69,(La/Yb)N为11.1.根据稀土元素比值、方差和以及REE分布模型判断,类似于佛子岭群和卢镇关群,后者可能是前者的主要源岩.三尖铺组和黑石渡组具有高的稀土总量,∑REE为264.8,328.2 μg·g-1,高Eu负异常,δEu为0.57,0.67和低的Eu/Sm比值(0.18～0.19),不同于大别山地区变质岩,其源岩值得进一步研究.正阳关组稀土元素特征类似大别杂岩和卢镇关群,表明大别杂岩在新第三纪遭受剥蚀,和卢镇关群一并成为前者的源岩.淮南地区中生代砂岩具有低的稀土总量,∑REE为80.9 μg·g-1,δEu为0.66,(La/Yb)N为5.7,不同于大别山北缘砂岩以及变质岩,说明其物源不是来自于大别山地区.     

Mineralogical and Geochemical Characteristics of the Human Body Ash Residue

The article is devoted to the element composition of the human body ash residue of some Russian cities. It presents the element composition of the human body ash residue, the distribution of elements in the ash residue depending on age and sex. The specific elements of different cities, showing the possible influence of the environmental conditions on the element composition of the human body ash residue. The main objective of this paper is to study the element composition of the human body ash residue and determine the regional characteristics. The methods of instrumental neutron activation analysis and inductively coupled plasma mass spectrometry were applied, an electronic microscope being used as a tool. The result of the research is 63 elements identified within in the human body ash residue. The issue is topical as it expands the knowledge of rare and radioactive elements within the human body and contributes to medicine, for example, by identifying the chemical elements to be included in a person's diet.     

Influence of sample pre-treatment on the determination of trace silver and cadmium in geological and environmental samples by quadrupole inductively coupled plasma mass spectrometry

The suitability of three different digestion procedures has been evaluated with regard to the quantitative determination of trace amounts of silver and cadmium in geological and environmental samples. Procedure A: extraction with aqua regia in an open vessel system; Procedure B: extraction with aqua regia in a closed pressurized vessel system; Procedure C: digestion with HF + HNO₃ in a closed pressurized vessel system. It was found that procedure A represented an effective way of extracting analytes from different types of geological samples while the effect of extracting interfering metals is low. Because it is interference-free, poses a low risk of contamination and is time-saving, sample treatment procedure A was preferred. For this digestion procedure, a series of Chinese geological reference materials was determined by ICP-MS, the results of which were found to be in reasonable agreement with the certified values.     

A nonelectrolyte local composition model and its application in the correlation of the mean activity coefficient of aqueous electrolyte solutions

The local composition models have been widely used for the correlation of activity coefficient of nonelectrolyte and electrolyte solutions. A new equation for the excess Gibbs energy function is developed based on the local composition expression of Wilson and the random reference state. This new function, the nonelectrolyte Wilson nonrandom factor (N-Wilson-NRF) model, is presented in the form of a molecular framework so that it can be used for both nonelectrolyte and electrolyte solutions. Without any particular assumptions for ionic solutions, the new function is used to described the short-range contribution of the excess Gibbs energy of electrolyte solutions. The long-range contribution is represented by Pitzer–Debye–Hückel model. With two adjustable parameters per electrolyte, the new model is applied to correlate the mean activity coefficients of more than 150 binary aqueous electrolyte solutions at 25 °C. The results are compared with various local composition models such as the electrolyte-NRTL, electrolyte NRF-Wilson and electrolyte-NRTL-NRF models. The comparison of the results with experiment demonstrates that the new model can correlate the experimental data accurately. Moreover, the model shows high precision of predictability for the osmotic coefficient of binary electrolyte solutions.     

Copper(II)-cetyltrimethylammonium chloride-chromal blue G ternary complex and its application to the spectrophotometric determination of copper(II)

A sensitive spectrophotometric method for the determination of copper(II) based on a ternary complex with chromal blue G, a triphenylmethane reagent in the presence of cetyltrimethylammonium chloride, is described. The sensitivity of color reaction between copper and chromal blue G has been greatly increased by the sensitizing action of cetyltrimethylammonium chloride, a cationic surfactant. The color development of the ternary complex can be utilized in the highly sensitive spectrophotometric determination of copper. The molar absorptivity of the binary complex between copper and chromal blue G ε_630nm = 9.56 × 10³liters · mol⁻¹ · cm⁻¹ is enchanced on ternary complex formation to ε_{542 nm} = 4.78 × 10⁴liters · mol⁻¹ · cm⁻¹. The ternary complex gave a maximal absorbance at 542 nm in the pH range 9.8–11. Beer's law is obeyed up to at least 1.2 ppm of copper. The maximal absorbance of the ternary complex was found to develop within 5 min and then it remains constant for several hours. The formation constant of the ternary complex is calculated to be 8.6 × 10¹⁰ under these conditions.     

Determination of thiosemicarbazide alone and in its metal complexes with arylhalosulfonamides

The behavior of 10 arylhalosulfonamides as oxidimetric analytical reagents toward thiosemicarbazide (TSC) alone or in its metal complexes has been critically examined and general procedures for its estimation have been developed. The proposed analytical techniques are simple and reproducible. These procedures are also useful for computing the number of TSC ligands present in the complexes. The oxidation involves twelve-electron change per TSC molecule with all the oxidants. The complexes have been prepared and characterized by elemental analyses and IR spectra.