Effect of solvent type on polycondensation of TEOS catalyzed by DBTL as used for stone consolidation

We have investigated the effect of solvent in the sol–gel process of tetraethylorthosilicate (TEOS) when di-n-butyltin dilaurate (DBTL) is used as polycondensation catalyst. Two sets of materials similar to those employed in the field of stone consolidation were prepared in the laboratory by using either protic or aprotic solvents: (1) xerogels from TEOS/DBTL, and (2) composites from TEOS/colloidal silica particles/DBTL. The results have shown that the solvent directly influences the aggregation pathway of the condensates. For a mixture of methyl ethyl ketone/acetone (aprotic solvents), gels with a higher degree of condensation were obtained. In the case of TEOS xerogels, the materials are essentially non-porous. Additionally, the incorporation of colloidal silica particles induces an important increase in porosity, which is even more dramatic when ethanol is used as solvent, through the formation of micro and mesoporous materials as the concentration of particles is increased. A TEOS polymerization pathway is suggested depending on which system of solvents is used. Various analytical techniques were used to characterize the materials obtained.     

Towards the identification of plant and animal binders on Australian stone knives

There is limited information regarding the nature of plant and animal residues used as adhesives, fixatives and pigments found on Australian Aboriginal artefacts. This paper reports the use of FTIR in combination with the chemometric tools principal component analysis (PCA) and hierarchical clustering (HC) for the analysis and identification of Australian plant and animal fixatives on Australian stone artefacts. Ten different plant and animal residues were able to be discriminated from each other at a species level by combining FTIR spectroscopy with the chemometric data analysis methods, principal component analysis (PCA) and hierarchical clustering (HC). Application of this method to residues from three broken stone knives from the collections of the South Australian Museum indicated that two of the handles of knives were likely to have contained beeswax as the fixative whilst Spinifex resin was the probable binder on the third.     

复完备随机内积模上的随机酉算子群的Stone表示定理

设[a,b]是有限实区间,(S,∥·∥)是完备的随机赋范模并赋予(ε,λ)-拓扑.在本文中,我们首先引进了从[a,b]到S的抽象值函数的Riemann积分并给出值域几乎处处有界的连续函数Riemann可积的一个充分条件.然后我们研究了随机谱测度和随机测度之间的关系.最后,在上述两个准备工作的基础之上,我们建立了复完备随机内积模上随机酉算子群的Stone表示定理.     

A canonical decomposition for linear operators and linear relations

An arbitrary linear relation (multivalued operator) acting from one Hilbert space to another Hilbert space is shown to be the sum of a closable operator and a singular relation whose closure is the Cartesian product of closed subspaces. This decomposition can be seen as an analog of the Lebesgue decomposition of a measure into a regular part and a singular part. The two parts of a relation are characterized metrically and in terms of Stone’s characteristic projection onto the closure of the linear relation.     

广西邕宁顶蛳山遗址出土黑色石料材质的光谱无损分析

石质材料鉴定是旧石器时代考古学研究的基础,因为石质种类会影响石器的制作技术、器物形态、工具类型,从而进一步制约遗址的石工业面貌乃至文化面貌。然而,仅从外观上对石器材质进行判定有很大的不确定性,特别是在鉴别黑曜石和玻璃陨石这类外观极其相似的天然玻璃质材料,大量案例表明人工目验的结果是不准确的,经常会出现误判的情况。因此,越来越多的研究开始借助现代科学仪器对石器材质进行鉴定。顶蛳山遗址作为岭南地区一处十分重要的石器时代遗址,为我们了解广西地区史前文化特征与内涵,探讨广西与周围地区史前文化交流提供了十分宝贵的资料。然而,对于出土在顶蛳山遗址中的大量黑色石器,发掘者们对这些石器的材质一直存疑。为了确定顶蛳山遗址出土黑色石料的材质,利用拉曼光谱、红外光谱和能量色散X射线荧光光谱（ED-XRF）等分析手段对其进行了原位无损材质鉴定。Raman分析表明,所有样品均为非晶态SiO₂类物质;同时样品的均在380 cm-1处出现极强吸收峰,提示样品中可能含有黄铁矿。所有样品的红外光谱在1 200~900 cm-1处平滑且不见明显肩峰,同时在750~500 cm-1处不见明显吸收峰,表明样品不含斜长石、石英等矿物,这与玻璃陨石的物相特征相吻合。ED-XRF结果表明,样品的主要成分是SiO₂和Al₂O₃,且其碱土金属（RO）和铁含量高而碱金属含量低（R₂O）,R₂O/RO小于1、K₂O/CaO的比值处于0.8～1.6之间,这些成分特征均与玻璃陨石相符。综合以上分析结果,可确定本文分析的石料样品均是玻璃陨石。分析结果对于进一步探讨顶蛳山遗址出土黑色石料的产地,顶蛳山遗址先民的活动范围及其与周边地区史前文化的交流与互动都具有重要参考价值。     

试论黄岩委羽山“方石”的科学与文化内涵

浙江省台州市黄岩区城南的委羽山产有＂方石＂,据称可用于治疗顽疾,为历代文人所赞美.经XRD和能谱测定,方石原为黄铁矿,后因蚀变与氧化成赤铁矿,其中含有微量的砷元素.这种微量的砷元素可能对人体的某些疾病具有一定的治疗作用.利用委羽山方石文化,可以开发科普旅游.同时,其所在的委羽山,号为道教＂第二洞天＂,亦可充分发掘道教文化,有效整合区内外各种相关道教资源,开发形成以道教文化为主题的旅游地,以推进黄岩城南新区的迅速发展.     

石材主量元素和微量元素测定的酸溶与碱熔分解方法比较

酸溶和碱熔分解石材标样,ICP-AES和ICP-MS法进行常量元素及微量元素的测定,分析结果的比较发现,根据不同的的石材类型、所需分析的元素种类以及研究目的,采用适当的样品分解方法,可以获得准确的常量元素和微量元素数据。