SUMMARY OF CHINA-MADE X-RAY THICKNESS GAUGES FOR STEEL INDUSTRIES

There are two kinds of China- made X- ray thickness gaugemeters i.e. dual beam- dual detector system and single beam- single detector system- SM series, the latter is used dominantly in Chinese steel industries. The performance comparison between domestic and foreign instruments as well as its developments and applications is presented in this paper.

Measurement and analysis of defects in high-performance concrete with three-dimensional micro-computer tomography

In order to investigate the effects of two mineral admixtures （i. e., fly ash and ground slag）on initial defects existing in concrete microstructures, a high-resolution X-ray micro-CT（ micro-focus computer tomography）is employed to quantitatively analyze the initial defects in four series of highperformance concrete （HPC）specimens with additions of different mineral admixtures. The nigh-resolution 3D images of microstructures and filtered defects are reconstructed by micro- CT software. The size distribution and volume fractions of initial defects are analyzed based on 3D and 2D micro-CT images. The analysis results are verified by experimental results of watersuction tests. The results show that the additions of mineral admixtures in concrete as cementitious materials greatly change the geometrical properties of the microstructures and the spatial features of defects by physical-chemistry actions of these mineral admixtures. This is the major cause of the differences between the mechanical behaviors of HPC with and without mineral admixtures when the water-to-binder ratio and the size distribution of aggregates are constant.

Characterization of Ga NAs/ Ga As and Ga In NAs/ Ga As Quantum Wells Grown by Plasma-Assisted Molecular Beam Epitaxy: Effects of Ion Damage

The effects of ion damage on Ga NAs/Ga As and Ga In NAs/Ga As quantum wells ( QWs) grown by plas- ma- assisted molecular beam epitaxy have been investigated. Itis found thation damage is a key factor affecting the quality of Ga NAs and Ga In NAs QWs. Obvious appearance of pendello¨ sung fringes in X- ray diffraction pattern and remarkable im provement in the optical properties of the samples grown with ion removal magnets are observed.By removing nitrogen ions,the PL intensity of the Ga In NAs QW is improved so as to be comparable with that of Ga In As QW. The stronger is the magnetic field,the m ore obvious the PL intensity im provement would be.

Chemical and molecular characterization of Hong Dangshen,a unique medicinal material for diarrhea in Hong Kong

Aim To investigate the plant origin and the identity of the red substance on the surface of Hong Dangshen, a unique medicinal material for diarrhea in Hong Kong. Methods The HPLC fingerprints and 5S rRNA gene spacer sequences of Hong Dangshen were obtained and compared with those of genuine species of Radix Codonopsis. The X-ray diffraction spectrum of the red substance was analyzed and compared with that of Halloysitum fingerprints to the Codonopsis species and the highest similarity to Rubrum. Results Hong Dangshen showed very similar HPLC Codonopsis pilosula var. modesta in terms of 5S rRNA gene spacer sequences. The X-ray diffraction spectrum of the red substance was consistent with that of Halloysitum Rubrum. Conclusion The source plant of Hong Dangshen was suggested to be Codonopsis pilosula var. modesta, one of the genuine original plants of Radix Codonopsis （Dangshen） in the China Pharmacopoeia （2005 edition）. The red substance on the surface of Hong Dangshen was indicated to be Halloysitum Rubrum, a traditional medicinal mineral for chronic diarrhea. Our data suggest that Hong Dangshen is derived from the roots of Codonopsis pilosula var. modesta which has been processed with Halloysitum Rubrum, and the name is suggested to be Radix Codonopsis Praeparata Halloysita Rubra.

X-ray spectra induced in highly charged 40Ar^q+ interacting with Au surface

By use of optical spectrum technology, the spectra of X-ray induced by highly charged 40Arq+ ions interacting with Au surface have been studied. The results show that the argon Kα X-ray were emitted from the hollow atoms formed below the surface. There is a process of multi-electron exciting in neutralization of the Ar16+ion, with electronic con-figuration 1s2 in its ground state below the solid surface. The yield of the projectile Kα X-ray is related to its initial electronic configuration, and the yield of the target X-ray is related to the projectile kinetic energy.

NON-DESTRUCTIVE MEASUREMENTS OF LEAD AND BARIUM IN ARCHAEOLOGICAL BONE SAMPLES USING XRF

The lead and barium contents in sixteen archaeological bone samples from 10 persons buried in Dalsby, Sweden, were determined by means of X- ray fluorescence analysis using two "Co sources for excitation and a planar Ge detector for registration of the X- rays. The lead concentrations were found to be less than 168μ g/g, and the barium concentrations were in the range of 15- 97μg/g.

Study of (Ga, Mn)N prepared by Mn-ion implantation using optical techniques

This paper reports that （Ga, Mn）N is prepared using implantation of 3at.% Mn Ions into undoped GaN. Structural characterization of the crystals was performed using x-ray diffraetion（XRD）. Detailed XRD measurements have revealed the characteristic of Mn-ion implanted GaN with a small contribution of other compounds. With Raman spectroscopy measurements, the spectra corresponding to the intrinsic GaN layers demonstrate three Raman active excitations at 747, 733 and 566 cm-1 identified as EI（LO）, A1 （LO） and E~, respectively. The Mn-doped GaN layers exhibit additional excitations at 182, 288, 650 725, 363, 506cm^-1 and the vicinity of E~ mode. The modes observed at 182, 288, 650 725em 1 are assigned to macroscopic disorder or vacancy-related defects caused by Mn-ion implantation. Other new phonon modes are assigned to Mnx-Ny, Gax-Mny modes and the local vibrational mode of Mn atoms in the （Ga, Mn）N, which are in fair agreement with the standard theoretical results.

Surface Modification of Titanium by Producing Ti/TiN Surface Composite Layers via FSP

In this paper, we report the use of blowing nitrogen gas for the successful fabrication of a composite layer composed of Ti/TiN on a substrate of commercially pure titanium （cp-2） using the friction stir processing technique. The prepared composite layer was characterized by X-ray diffraction, scanning electron microscopy and energy-dispersive X-ray spectrometry. The maximum microhardness of the Ti/TiN composite reached 1024 HV, which is 6.4 times higher than that of the titanium substrate. The results of wear test indicated that the Ti/TiN composite layer possesses excellent abrasive and adhesive wear resistance because of the formation of the TiN and its high hardness.