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Copper matrix-matched calibration samples were prepared by doping high purity copper powders (99.999%, 500–600 μm) with multi-element standard solutions with a total of 72 elements, and then the relative sensitivity factors (RSFs) of the 72 elements in both microsecond-pulsed and continuous direct current (dc) modes were determined by using Element GD type glow discharge mass spectrometry (GD-MS). The ability of pulsed and continuous dc-GD-MS to quantitatively determine trace elements in copper was demonstrated after calibration using the RSFs. The results showed that the uncertainty level of GD-MS analysis after calibration was comparable with that of ICP-MS and ICP-OES analysis. In order to standardize calibration sample preparation procedures, the doping concentration, pressed powder tablet compactness and tablet homogeneity were optimized. Good recovery (85% to 115%) was obtained. Good pressed powder tablet compactness and tablet homogeneity were obtained, which were expressed as relative standard deviations (

The conventional transrectal ultrasound (TRUS) probe for transperineal needle insertion is typically a sagittal viewing linear array or combined with another transverse curvilinear array. Physicians are required to manually move and rotate the probe back and forth to determine the needle trajectory or to render 3D volume. For the hands-free 3D imaging guidance of transperineal needle insertion, this paper proposes a reflector-based 3D TRUS imaging probe. The proposed probe is enabled by motorizing rotation of a forward-viewing array transducer and bending the ultrasound beam to cover whole prostate utilizing an acoustic mirror as reflector. The proposed device is capable of providing an arbitrary angled B-mode slice with respect to prostate based on the motorized probe rotation angle adjustment, and enables to render 3D images with volume-based reconstruction. In the experimental validation with the cyst phantom, the contrast-noise ratios in the 0 and 90-degree of rotation angle were 4.36 and 4.05 dB in the image acquisition with reflector, and 4.26 and 5.07 dB in that without reflector, respectively. Also, the 3D appearance of cyst can be rendered with maximum intensity projection. These results demonstrated the limited image quality deterioration by adding reflector, and indicate the reflector-based TRUS probe has a potential to improve the guidance of transperineal needle insertion.

High-purity silicon power was doped with standard solutions containing 15 elements, and a high-purity indium tablet was prepared by the melting of indium pellets. An In-Si tablet, which is mechanically stable and thus suitable as a calibration sample, was prepared by our pressing the doped silicon power on the high-purity indium tablet. The matrix effect was studied by our investigating the variations of measured mass fractions (standard relative sensitivity factor, StdRSF, calibration) of doped impurities in the In-Si tablet, which provides a series of matrixes with different mass ratios of In to Si. For all the elements, the relative standard deviations of the measured mass fractions of impurities were less than 30%. The RSFs of the glow discharge mass spectrometer (Element GD) were obtained, and the results showed that three RSFs derived from the In-Si tablet with low, intermediate and high mass ratios of In to Si, respectively, agreed with the mean RSF within an uncertainty interval of 30%. The measurement of Fe and Al matrix certified reference materials further demonstrated that the RSFs generated from a matrix can be used for the calibration of another matrix, and the uncertainty was within 30%. Finally, another doped silicon powder was measured with the glow discharge mass spectrometer, which was calibrated by the mean RSFs from the In-Si tablet, and the analytical results obtained by glow discharge mass spectrometry are in good agreement with the analytical results obtained by high-resolution inductively coupled plasma mass spectrometry. Graphical abstract ᅟ.

The triaxial creep compression tests of compacted loess samples are conducted with a new set of modified triaxial compression apparatus. With the new apparatus, the loess sample can be scanned with CT machine at the same time during compression process. The different damage process of compacted loess sample is directly observed for the first time with CT images and CT numbers. The initiation mechanisms of loess micro-crack during different creep compression processes are analyzed with CT images.