Combined PIXE and SEM study of the behaviour of trace elements in gel formed around implant coated with bioactive glass

Bioactive glasses are used as coating biomaterials to facilitate anchorage of metallic prostheses implanted into the body. The aim of this work is to study the behavior of gel formed in contact with alloys and BVA and BVH bioactive glasses implanted. Cylinders of metallic implants composed by Ti, Al and V, are coated with bioactive glass. Three sheep were implanted for different time length: 3, 6 and 12 months in the femoral epiphysis. Results obtained with particle induced X-ray emission and scanning electron microscopy show that BVA coating induces a better contact between the metallic implant and bone. On the other hand, BVH coating prevents corrosion from the metallic implant.     

部分种子成分的特征X射线在等效生物材料中衰减的测定

用Ｓｉ（Ｌｉ）探测器实现了Ｎａ、Ｍｇ、Ｓ、Ｃｌ的特征Ｘ射线在有机膜中的相对衰减以及与Ｏ、Ｋ元素的特征Ｘ射线能量相当的Ｘ射线或轫致辐射在有机膜中的相对衰减，分别得出了它们减的数学描述，并把实验得到不同能量的Ｘ射线在有机膜中的质量吸收系数与Ｂｅｒｋｅｌｅｙ的ＯＣＧ软件计算出的结果相比，相关都小于３０％。     

Application of Rachinger''s method to separate overlapped doublets in the X-ray photoelectron spectrum

Rachinger's method of separating ₁ and ₂ doublets in X-ray emission spectra is applied for the first time to separate the superimposed doublets due to spin-orbit coupling. This method has been applied to separate closely lying doublets such as (Ag 4p_3/2and Ag 4p_1/2, (Ni 3p_3/2and Ni 3p_1/2) and (Cu 3p_3/2and Cu 3p_1/2). The intensities ratios of the separated peaks are measured and compared with the ratios obtained from a first-order calculation. An excellent agreement between the measured and calculated ratios are obtained. Residual background intensities compared with the estimated values are found to agree within certain uncertainties.     

超低膨胀陶瓷K_（2x）Ba_（1－x）Zr_4（PO_4）_6系统的X射线衍射

用高温Ｘ射线衍射方法对磷酸锆钡钾系统陶瓷材料的各向异性热膨胀作了研究．对七个组份试样的７７套高温Ｘ射线衍射图作了仔细的指标化和精密点阵常数测定．点阵常数随温度作非线性变化·对Ｋ_２ｘＢａ_１－ｘＺｒ_４（ＰＯ_４）_６的不同组份不同温度（３００～１３００Ｋ）的热膨胀系数。α_ａ、α_ｃ、　作了测定·该系统零膨胀陶瓷的组份为Ｋ_１．１６Ｂａ_０．４２Ｚｒ_４（ＰＯ_４）_６（ｘ＝０．５８）     

Standard reference materials for cements

The eight portland cements and two calcium aluminate cements in the Standard Reference Material (SRM) 1880 series are among the most popular SRMs in the catalog of the National Institute of Standards and Technology (NIST) Standard Reference Materials Program. Numerous laboratories rely on them for elemental analysis and qualification for ASTM C 114-00 Standard Test Methods for Chemical Analysis of Hydraulic Cement. NIST has collected new candidate materials from around the world and partnered with Construction Technology Laboratories (CTL) in their preparation and certification. This paper describes the procedures taken at NIST and CTL to prepare and test materials for certification including the homogeneity testing, the X-ray fluorescence methods and the statistical data analysis performed for value assignment.     

Use of helical parameters to generate candidate conformations for crystal packing: illustrative application to a polyimide

This communication describes the application and extension of a method for calculating the helical parameters with which to describe molecular conformations. The method, which was originally developed by Shimanouchi and others, is applied to a polyimide of 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) and 2,2-dimethyl-1,3-(4-aminophenoxy)propane (DMDA) which has eight torsional bonds in the chemical repeat unit. Discrete low energy states for these torsions were determined by Ramanchandran energy maps of sequential dihedral pairs or single bond torsional energy diagrams. The total number of possible low energy conformations for these states is 1152 including conformationally related isoenantiomorphs. The method conveniently generates the conformations for subsequent crystal structure packing and refinement. Consideration of these together with the X-ray data of Cheng and co-workers reduces the number to about 15 with about a 2/1 conformation and a c axis of approximately 49.2 Å. Of these, about half appear to be good candidates for crystal packing.     

特征X射线能谱法测定Fe^＋注入小麦种子的深度

用１１０ｋｅＶ Ｆｅ＾＋离子束垂直注入小麦种胚后，在扫描电子显微镜上沿种子纵沟剖面，在不同深度上测量Ｆｅ元素被激发出的特征Ｘ射线强度分布，结果表明分布呈指数衰减，与晶体中的热扩散分布相类似，并对此进行了讨论。     

Residual Stress Evolution in Repair Welds

Abstract: The aim of this paper is to study the influence of the repair procedure on the evolution of residual stress distribution in butt welds. C-Mn steel coupon plates of 11 mm thickness were prepared, subjected to stress relief heat treatment and welded with two beads, using the gas metal arc welding process. After the deposition of two weld beads, two successive repair welds were made on the middle length of the second bead. Longitudinal and transverse residual stresses were measured in the vicinity of the weld, after deposition of the two weld beads and after each repair weld. Residual stress evaluation was conducted using an X-ray diffraction method. The repair welds caused a decrease in magnitude of the initial longitudinal residual welding stresses, and an increase of the transverse residual stress magnitude, in tension at points within the repair length, and in compression at points outside the repair length.     

Yttrium sol–gel coating effects on the cyclic oxidation behaviour of 304 stainless steel

The present results reveal the interest of sol–gel coating technique to improve 304 steel high temperature oxidation resistance. An yttrium sol–gel coating appears to enhance the oxidation resistance during isothermal oxidation test, to decrease widely the oxide weight gain and to reduce the initial transient oxidation stage generally observed in the case of blank steels. Moreover, the experimental results confirm that yttrium sol–gel coating also plays a significant role on the cyclic oxidation behaviour of the 304 steel. In fact, the yttrium addition promotes remarkably the prolongation of the period during which the oxide scale still remains adherent to the substrate.     

Biodegradation and corrosion behavior of manganese oxidizer Bacillus cereus ACE4 in diesel transporting pipeline

The degradation problem of petroleum products arises since hydrocarbon acts as an excellent food source for a wide variety of microorganisms. Microbial activity leads to unacceptable level of turbidity, corrosion of pipeline and souring of stored product. The present study emphasizes the role of Bacillus cereus ACE4 on degradation of diesel and its influence on corrosion of API 5LX steel. A demonstrating bacterial strain ACE4 was isolated from corrosion products and 16S rRNA gene sequence analysis showed that it has more than 99% similarity with B. cereus. The biodegradation and corrosion studies revealed that B. cereus degraded the aliphatic protons and aromatic protons in diesel and is capable of oxidizing ferrous/manganese into oxides. This is the first report that discloses the involvement of manganese oxidizer B. cereus ACE4 on biodegradation of diesel and its influence on corrosion in a tropical country pipeline.