Advanced combined application of μ-X-ray diffraction/μ-X-ray fluorescence with conventional techniques for the identification of pictorial materials from Baroque Andalusia paintings

The process of investigating paintings includes the identification of materials to solve technical and historical art questions, to aid in the deduction of the original appearance, and in the establishment of the chemical and physical conditions for adequate restoration and conservation. In particular, we have focused on the identification of several samples taken from six famous canvases painted by Pedro Atanasio Bocanegra, who created a very special collection depicting the life of San Ignacio, which is located in the church of San Justo y Pastor of Granada, Spain. The characterization of the inorganic and organic compounds of the textiles, preparation layers, and pictorial layers have been carried out using an XRD diffractometer, SEM observations, EDX spectrometry, FT-IR spectrometry (both in reflection and transmission mode), pyrolysis/gas chromatography/mass spectrometry and synchrotron-based μ-X-ray techniques. In this work, the advantages over conventional X-ray diffraction of using combined synchrotron-based μ-X-ray diffraction and μ-X-ray fluorescence in the identification of multi-layer paintings is demonstrated.     

Spaces of type BLO on non-homogeneous metric measure

Let (, d, μ) be a metric measure space satisfying the so-called upper doubling condition and the geometrically doubling condition. In this paper, we introduce the space RBLO(μ) and prove that it is a subset of the known space RBMO(μ) in this context. Moreover, we establish several useful characterizations for the space RBLO(μ). As an application, we obtain the boundedness of the maximal Calderón-Zygmund operators from L ^∞(μ) to RBLO(μ).     

多圆柱上μBloch空间之间的加权Cesàro算子

分别给出了多圆柱上μ-Bloch空间βμ之间、βμ,0空间之间的加权Cesàro算子Tg为有界算子和紧算子的充要条件.     

原位微区同步辐射X射线荧光和近边吸收谱研究拟南芥幼苗及根际土壤中铅分布与形态特征

为了从组织和器官水平研究植物在铅锌矿山开采区尾矿坝土壤中植物中毒和胁迫机制,使用同步辐射微束X射线荧光技术(μ-SRXRF)研究了K,Ca,Mn,Fe,Cu,Zn,Pb等元素在云南某铅锌矿区尾矿坝土壤中生长的拟南芥幼苗中的分布特征。发现Pb易富集于植物根部,也容易富集在植物顶端叶芽部位,这是很多研究没有发现的。整株幼苗中Pb都与Mn形成明显的竞争分布特征。导致植株中毒凋亡的原因可能是Pb造成的拟南芥顶端幼芽的氧化压力,以及Pb分布对Mn等植物必需元素的吸收和分布的抑制。为研究Pb在土壤中的形态和植物可利用性,针对拟南芥及其根际土壤中开展了Pb L3边X射线吸收近边精细结构谱(XANES)研究,发现尾矿坝土壤种植的拟南芥根际土壤Pb主要以PbO(64.2%),Pb(OH)2(28.8%),Pb3O4(6.3%)形式存在,而非Pb矿物矿石或有机Pb形式存在,本尾矿坝土壤中Pb的植物可利用水平不高。进一步开展土壤中Pb进入植物的过程以及该过程中Pb的形态发生的变化,尤其是溶解性有机质在其中的角色,是开展重金属胁迫下植物中毒和解毒机制研究的重要前提。     

Synthesis and Characterization of Some Unique Heterocyclic Derivatives Containing Aluminium(III) Atoms in 4- and 6-Co-Ordination States∶ Reaction of Bis(β-Diketonato) Aluminium (III)-DI-μ-Isopropoxo-DI-Isopropoxo Aluminium(III) with Triphenylsilanol and Diphenylsilanediol

Reactions of bis ( g -diketonato) aluminium(III)-di- w -isopropoxo-di-isopropoxo-aluminium (III), [CH₃COCHCOR)2Al( w -OPrⁱ)₂Al(OPrⁱ) ₂], with triphenylsilanol, Ph₃SiOH, in 1:1 and 1:2 molar ratios and with diphenylsilanediol, Ph₂Si(OH)₂, in a 1:1 molar ratio, have resulted in the synthesis of [(CH₃COCHCOR)₂Al( w -OPrⁱ)₂Al(OSiPh₃)(OPrⁱ)], [(CH₃COCHCOR)₂Al( w -OPrⁱ)₂Al(OSiPh₃)₂] and [(CH₃COCHCOR)₂Al( w -OPrⁱ)₂Al(OSiPh₂O], respectively. These are soluble in a variety of organic solvents ( e.g. , benzene, chloroform and dimethylsulfoxide) and show dinuclear behaviour in chloroform. These derivatives have been characterized by elemental analyses, molecular weight measurements, IR and NMR (¹H, ¹³C and ²⁷Al) studies.     

Studies on Mn(II) and Mn(IV) Complexes of an Unsymmetrical Bidentate Donor,N(4-Chlorophenyl)-Pyridine-2-Aldimine (ClL): Crystal Structure of [Mn(ClL)2(NCS)2]

The synthesis, characterisation and X-ray structure of an Mn(II) compound, [Mn(ClL)₂(NCS)₂], is described. Oxidation of the compound by H₂O₂ leads to a mononuclear Mn(IV) compound [Mn(ClL)(ClL')(NCS)₂]ClO₄·2H₂O where one of the ClL ligands is oxidised to the corresponding amide ClL'. Oxidation of [Mn(ClL)₂(NCS)₂] by Ce(IV), however, leads to a binuclear Mn(IV) compound [Mn₂O(ClL')₃(ClL)(H₂O)₂](NCS)₂ClO₄·2MeCN. Electron transfer behaviour of the compounds was investigated by cyclic voltammetry and differential pulse voltammetry.     

X射线显微CT用于大鼠骨小梁结构分析的研究

应用X射线显微CT(X-μCT)对正常及骨质疏松大鼠的骨小梁结构进行了分析,并与骨组织形态计量法的测量值进行了比较,探讨了X射线光谱技术在骨结构分析中的应用。实验对大鼠骨样品进行X-μCT扫描,扫描条件为 80 kVp,80 μA,360°旋转,帧平均4帧,角度增益 0.4°,分辨率14 μm。三维重建并分析了骨小梁结构,结构参数包括骨体积分数(BV/TV)、骨小梁厚度(Tb.Th)、骨小梁数量(Tb.N)以及骨小梁间隔(Tb.Sp)。结果表明,采用X-μCT分析不同组大鼠的骨小梁结构参数值之间存在显著差异(P<0.05),测定值与传统骨组织形态计量法的测定值显著相关,其中胫骨骨小梁BV/TV,Tb.Th,Tb.N,Tb.Sp的相关系数r分别为0.984,0.960,0.995,0.988,腰椎骨小梁各结构参数的相关系数分别为0.938,0.968,0.877,0.951。因此,X-μCT可以较好地呈现并区分正常骨组织、骨质疏松骨组织以及经雌激素治疗后骨组织的微观结构,可以实现对骨小梁结构参数的分析测定,与骨组织形态计量法相比是一种更精确、立体、快速且无损测量骨微结构和评价骨质量的方法。     

(μ-L1)(μ-L2)十羰基合三锇电子光谱的含时从头计算

用从头计算(ab initio)方法,在HF/CEP-4G水平上,全优化计算了Os₃(CO)₁₀(μ-L1)(μ-L2) [L1,L2=H,Cl,Br,I]簇合物的的分子几何构型,在此基础上对这些簇合物的前线轨道进行了讨论,发现对于M—M键,p轨道虽有贡献,但以s,d轨道的贡献为主,同时从Cl→I,随着桥配体原子序的增大,Os₃(CO)₁₀(μ-L)₂类簇合物的HOMO与NHOMO轨道能量依次升高,而Os₃(CO)₁₀(μ-H)(μ-L)类簇合物只有HOMO轨道能量依次升高,而Os₃(CO)₁₀(μ-L)₂类簇合物的LUMO与HOMO的能量差Δε_L-H及LUMO与NHOMO的能量差Δε_L-NH都依次变小,可以预示,簇合物的电子光谱基谱带将红移。用TDHF计算了这些簇合物的电子吸收光谱。计算结构表明,簇合物Os₃(CO)₁₀(μ-H)₂(I)的跃迁主要为π→σ*和σ→σ*,对于其他几个簇合物Os₃(CO)₁₀(μ-H)(μ-L) [L=Cl,Br,I] 和Os₃(CO)10(μ-L)₂[L=Cl,Br],电子吸收峰主要都发生在σ→σ*的跃迁。从Cl→I,随着桥配体原子序的增大,簇合物的电子光谱基谱带红移,且光谱线强度逐渐减弱。     

Synthesis and Crystal Structure of a New μ-Oxamide Trimeric Hetero-tetranuclear Complex

A novel oxamide-bridged trimeric tetranuclear complex 1 incorporating a macro- cyclic oxamide of formula {[(CuL)3Mn](ClO4)2}3 (macrocyclic oxamide L = 2,3-dioxo-5,6,14,15- dibenzo-1,4,8,12-tetraazacyclopentadeca-7,12-diene) was prepared and structurally characterized. The compound [(CuL)3Mn](ClO4)2 crystallizes in the trigonal system, space group with a = 22.434(17), b = 22.434(17), c = 18.82(2) (A), α = β = 90, γ = 120o, V = 8203(13) (A)3, Z = 6, Dc = 1.751g/cm3, μ(MoKα) = 1.557, F(000) = 4392, the final R = 0.083 and wR = 0.1727 for 9604 obser- ved reflections with I > 2σ(I). The single-crystal X-ray analysis shows that 1 is a trimeric complex. There are three similar constitutes, dissimilar conformations and asymmetrically independent 'building-block' [(CuL)3Mn] in one crystal cell of the title complex 1.