X射线可视化检查GIS设备技术研究

气体绝缘全封闭组合电器(GIS)是高压及超高压领域的常用设备,为实现其内部缺陷的系统检查,能有效地提升设备运作安全性、可靠性,需对GIS设备进行X射线可视化检查。本文在阐述GIS设备X射线可视化修系统结构组成的基础上,就GIS设备技术常见内部故障进行分析,然后指出X射线可视化检查对GIS设备的影响。期望能提升X射线可视化检查技术的应用水平,进而在提升GIS设备运作质量的同时,推动我国高压、超高压电力工程的有序发展。

Sol-Gel Synthesis and Structure-Property Relations in Silver Nanoparticles-Dispersed in GeO2 Matrix

Synthesis of Ag nanoparticles dispersed in germanium dioxide （GeO2） matrix was performed via sol-gel route. Analysis of the powder X-ray diffraction （XRD） pattern shows fcc cubic unit cell of Ag with lattice parameters： a = 4.0884 A, space group Fm-3m. Energy dispersive analysis of X-rays （EDAX） results show the presence of only GeO2 and Ag in the sample. The average crystallite sizes of Ag particles determined by Scherrer＇s relation are found to be i 8-47 nm. Observed sharp electron paramagnetic resonance （EPR） lineshapes at 8, 70 and 300 K with g-values of 2.004, 2.004, and 2.004, respectively, show that the Ag （5s~） electrons are localized in the Ag nanoparticles. The calculated value of the magnetic susceptibility is 1.014~ 10-5 emu/gG from the observed magnetic moments data at 300 K, which shows fairly strong paramagnetic nature of the material. Refinement of Ag crystal structure in space group Fm-3m with Ag atoms in 4（a） position shows the agreement bond length as 2.8909 ,＆. Calculated density of states below Fermi factors Rp= 67.22%, Rwp= 75.7%, Rexp= 0.06%, Z = 4 and Ag-Ag energy, EF, from -2 to -8 eV are due to valence d orbitals of Ag.

Variation of microfibril angle and its correlation to wood properties in poplars

The microfibril angle of seven poplar clones was determined by using X-ray diffraction technique. Microfibril angle, wood basic density, fiber length, fiber width and cellulose content were assessed for every growth ring at breast height for all sample trees. Significant variation in microfibril angle was observed among growth rings. Mean microfibril angle (MFA) at breast height varied from 7.8?to 28?between growth rings with cambial age and showed a consistent pith-to-bark trend of decline an-gles. Analysis of variance also indicated that there were significant differences in wood basic density, fiber length, fiber width and cellulose content between the growth rings, which had an increasing tendency from pith to bark. Correlations between MFA and examined wood properties were predominantly large and significant negative (?0.01), and the coefficients were -0.660 for cellulose content, -0.586 for fiber length, -0.516 for fiber width and -0.450 for wood basic density, respectively. Regression analysis with linear and curve estimation indicated that a quadratic function showed the largest R2 and the least standard error for describing the relationships between microfibril angle and measured wood properties, and the correlation coefficients were over -0.45 (n=125). The results from this study suggested that microfibril angle would be a good characteristic for improvement in the future breeding program of poplars.

The distribution and variation of elements in sediments off the Huanghe (Yellow) River mouth

Surface sediment samples collected off the Huanghe （Yellow） River mouth during the period 2007-2009 were analyzed for major and trace element concentrations. Concentrations of 16 elements were measured using X-ray fluorescence spectrometry. Results demonstrate that sediment grain size is the dominant factor controlling the spatial variations of elemental concentrations. Correlation and cluster analyses allowed classification of the study area into four geochemical regions： Regions Ⅰ and Ⅲare characterized by high concentrations ofAl2O3, Fe2O3, MgO, Na2O, K2O, Cr, Cu, Mn, Ni, Pb, V, and Zn, and contain fine-grained sediments with mean grain size （Mz）〈22 μm; and; Regions Ⅱ and Ⅳcontain mostly coarse-grained sediments, and are characterized by high concentrations of SiO2, Na2O, and Zr. The sediment entering the sea from the Huanghe River and its tributaries is enriched in Ca. Thus, the Ca/Al ratio was used as an indicator of the proportion of sediments in the study area that originated from the Huanghe River. Ca/Al ratios decrease from Regions Ⅰ and Ⅱ（located in the nearshore zone of the Huanghe River delta） to Regions Ⅲand Ⅳ（distributed in the offshore zone of the northern Huanghe River delta, southern and southeastern Laizhou Bay area）.

Liquidus and phase equilibria in CaO-SiO2-5%MgO-20%Al2O3-TiO2 system

The single hot thermocouple technique （SHTT） and high temperature equilibrium technique were combined to investigate the phase diagram of the CaO-SiO2-5%MgO-20%AlzO3-TiO2 system. The 1300 ℃ to 1500 ℃ liquidus lines are calculated according to the thermodynamic equations based on the pseudo-melting temperatures measured by the single hot thermocouple technique. The phase equilibria relationships are experimentally determined at 1400 ℃ using the high temperature equilibria technique followed by X-ray fluorescence （XRF）, X-ray diffraction（XRD）, scanning electron microscopy （SEM） and energy dispersive X-ray spectroscopy （EDX） analysis. The liquid phase（L）, melilite solid solution phase （（C2MSz,C2AS）ss）, diopside phase（CMS2） and perovskite phase （CaO·TiO2） are found. Coupled with the liquidus lines and equilibria results, the phase diagram is constructed for the specified region of the CaO-SiO2-5%MgO-20%Al2O3-TiO2 system.

Irreducible traumatic posterior hip dislocation with entrapment and a buttonhole effect

The authors reported the case of a 27- year-old man who sustained an irreducible postero-lateral traumatic dislocation of the hip with capsular and labral entrapment. Initial X-rays showed only a small acetabular fragment. After two attempts to reduce the hip with muscle paralysis under general anaesthesia failed, the patient was treated by immediate open reduction through a posterolateral approach. Surgical exploration of the hip revealed a small osteochondral fragment attached to a large piece of labrum and capsule, clogging the acetabulum. The femoralhead crossed over the torn capsule with a buttonhole effect. These elements were relieved, the bone fragment was fixed with a 2 mm screw and the capsule was repaired. At the 10- year follow-up, the functional outcome was excellent with a Harris score of 100 points and no signs of necrosis or osteoarthritis. The authors propose a literature review of this uncommon lesion.