Ge System Research Articles

Interaction of the component in Y–{V, Fe}–Ge systems at 870 K

This paper is part of a systematic study of the interaction of rare earth metals with transition metals and germanium. The interaction of components in Y–V–Ge and Y–Fe–Ge ternary systems was studied using X-ray diffraction and microstructure analyses. Isothermal sections of the systems have been constructed at 870 K. A new ternary compound YV 0.16 Ge 1.54 was found in Y–V–Ge system at the temperature of study. The crystal structure refinement of YV 0.16 Ge 1.54 was performed using X-ray powder diffraction method. It was indicated that the new compound belongs to CeNiSi 2 structure type (ST) (space group Cmcm ,Pearson symbol oS 16, a = 0.40815(1), b = 1.58775(5), c = 0.39429(1) nm, R B = 0.0286, R р = 0.0564, R wp = 0.0759). The existence of substitutional solid solution based onY 5 Ge 3 binary compound (ST Mn 5 Si 3 ) up to 10 at. % V was observed. V 3 Ge (SТСr 3 Si)binary germanide dissolves up to 3 at. % Y as evidenced by changes in the lattice parameter а = 0.4784 for V 3 Ge, а = 0.4789(2) nm for Y 3 V 72 Ge 25 sample. Existence of the following five ternary germanides: YFe 6 Ge 6 (ST TbFe 6 Sn 6 ), YFe 2 Ge 2 (SТ CeGa 2 Al 2 ),YFe 4 Ge 2 (SТ ZrFe 4 Si 2 ), Y 117 Fe 52 Ge 112 (SТ Tb 117 Fe 52 Ge 112 ) and YFe 1- x Ge 2 (SТ CeNiSi 2 ), was confirmed in Y–Fe–Ge ternary system at the temperature of study. The refinement of crystal structure of YFe 0.34 Ge 2 phase was performed by powder method (CeNiSi 2 – type, a = 0.41172(2), b = 1.58838(6), c = 0.39989(2) nm, R I =0.0193). On the basis of Y 5 Ge 3 binary compound (Mn 5 Si 3 -type) the existence of substitutional solid solution Y 5 Fe x Ge 3- x up to 5 аt. % Fe ( a = 0.8472(2); c = 0.6347(2) nm for Y 5 Ge 3 , a = 0.8462(1); c = 0.6378(2) nm for Y 62.5 Fe 5 Ge 32.5 ) was discovered. The substitution of M -component produces the change of character of phase diagrams, number of compounds, their composition and crystal structure. The number of ternary germanides in Y− M −Ge systems increases from 1 to 10 at V → Cr → Mn → Fe → Co → Ni transition and decreases to 5 at the transition to Cu. In all studied systems Y M 1- x Ge 2 compound with CeNiSi 2 -type is observed. Most ofR −M− Ge ternary systems are characterized by similar component interaction. The formation of R M 1- x Ge 2 compounds is the feature of Y−{V, Fe}−Ge and R−{Mn, Fe, Co, Ni, Cu}−Ge systems. These germanides are characterized by the presence of defects in the position of M component or statistical mixture ( M , Ge), which causes deviation of their compositions from ideal R M Ge 2 towards lower content of M component. Keywords: X-ray diffraction, EDX, phase equilibria, ternary compound, crystal structure.

Usefulness of longitudinal strain adjusted to regional thickness in hypertrophic cardiomyopathy

In hypertrophic cardiomyopathy (HCM), longitudinal strain analysis allows to early detect left ventricular (LV) contraction abnormalities despite preserved LV ejection fraction. In current software, the width of the region of interest (ROI) is the same over the entire myocardial wall and might analyze partially LV hypertrophic segments. The aim of this study is to evaluate a novel software for strain analysis with an adjustable ROI according to each segment thickness. We included 110 patients: 55 patients with HCM (HCM group) and 55 healthy subjects (age- and sex-matched control group). All pts underwent echocardiography using a Vivid 9 GE system and measurements were performed using EchoPAC software. Global longitudinal strain (GLS) and regional strain for each of the 17 segments were calculated with standard software (for 2 groups) and with software adjusted to the myocardial wall thickness (for HCM group). GLS was significantly decreased in the HCM group as compared to the control group (−15.1 ± 4.8% versus–20.5 ± 4.3%, P < 0.0001). In HCM group, GLS (standard method versus adjusted to thickness) was not significantly different ( P = 0.34). Interestingly, regional strain adjusted to thickness was significantly lower than standard strain in hypertrophic segments, especially in basal inferoseptal segment ( P = 0.0002), median inferoseptal segment ( P < 0.001) and median anteroseptal segment ( P = 0.02). Strain adjusted to thickness was still significantly lower in the most hypertrophic segments (≥ 20 mm) (−3.7 ± 3%, versus −5.9 ± 4.4%, P < 0.049 in the basal inferoseptal segment and −5.7 ± 3.5% versus −8.3 ± 4.5%, P < 0.0007 in the median inferoseptal segment). Analysis of strain adjusted to thickness had a better feasibility (97.5% versus 99%, P = 0.01). Analysis of longitudinal strain adjusted to regional thickness is feasible in HCM and allows a better evaluation of myocardial deformation, especially in the most LV hypertrophic segments.

R2-xTi3+xGe4 compounds in the R–Ti–Ge (R = Gd–Lu) systems

R2-xTi3+xGe4 compounds in the R–Ti–Ge (R = Gd–Lu) systems

Predictive value of q waves in inferior leads for the diagnosis of old inferior wall myocardial infarction

Background: A diagnosis of an old Inferior Wall Myocardial Infarction (IMI), on a routinely performed Electrocardiogram (ECG) often leads to further consultations and imaging studies. The aim of this study was to assess the predictive value of Q waves in inferior leads, alone or in combination with repolarization abnormalities, for the diagnosis of inferior wall myocardial infarction confirmed by imaging studies. Methods: Fifty-six patients, in whom computerized interpretation of the electrocardiogram resulted in the diagnosis of inferior wall myocardial infarction, and in whom imaging studies were also available, were included in this study. Electrocardiograms were performed using the GE MACHD 5500. Electrocardiograms were interpreted using the MUSE GE system. Echocardiograms and nuclear medicine cardiac imaging were performed and interpreted using standard equipment and techniques. S AS 9.3 software (SAS Institute, Inc., Cary, North Carolina) was used to calculate 95% exact binomial confidence intervals (CI) for the population PPVs. Results: Computerized interpretation of the ECGs leading to the diagnosis of old inferior wall myocardial infarction when compared with inferior wall myocardial infarction confirmed by imaging studies, had a positive predictive value of 52.78%. Adding the criteria of Q waves wider than 0.04 ms, using manual interpretation of ECG, increased the positive predictive value of the test to 80%. However, the presence of ST changes and/or negative or isoelectric T waves, in the presence of diagnostic Q waves in the inferior leads, increased the positive predictive value to 92%. Conclusion: These results suggest that the computerized interpretation of ECG results in a high rate of false positive readings of old inferior myocardial infarction. This may result in overutilization of imaging modalities. Presence of diagnostic Q waves in inferior leads, if accompanied by repolarization abnormalities, improves the accuracy of the electrocardiogram for the diagnosis of inferior wall myocardial infarction..

Influence of magnetic field, chemical pressure and hydrostatic pressure on the structural and magnetocaloric properties of the Mn–Ni–Ge system

The magnetic, structural and thermomagnetic properties of the MM’X material system of MnNiGe are evaluated with respect to their utilization in magnetocaloric refrigeration. The effects of separate and simultaneous substitution of Fe for Mn and Si on the Ge site are analysed in detail to highlight the benefits of the isostructural alloying method. A large range of compounds with precisely tunable structural and magnetic properties and the tuning of the phase transition by chemical pressure are compared to the effect of hydrostatic pressure on the martensitic transition.We obtained very large isothermal entropy changes of up to J based on magnetic measurements for (Mn,Fe)NiGe in moderate fields of 2 T. The enhanced magnetocaloric properties for transitions around room temperature are demonstrated for samples with reduced Ge, a resource critical element. An adiabatic temperature change of 1.3 K in a magnetic field change of 1.93 T is observed upon direct measurement for a sample with Fe and Si substitution. However, the high volume change of 2.8% results in an embrittlement of large particles into several smaller fragments and leads to a sensitivity of the magnetocaloric properties towards sample shape and size. On the other hand, this large volume change enables to induce the phase transition with a large shift of the transition temperature by application of hydrostatic pressure (72 K ). Thus, the effect of 1.88 GPa is equivalent to a substitution of 10% Fe for Mn and can act as an additional stimulus to induce the phase transition and support the low magnetic field dependence of the phase transition temperature for multicaloric applications.

Crystalline Electric Field Level Scheme of the Non‐Centrosymmetric CePtSi3

The crystalline electric field (CEF) excitations in CePtSi3 with the non-centrosymmetric structure were investigated by inelastic neutron scattering (INS) experiment. CEF excitations were observed at 5.3 and 17.5meV. We discuss the CEF parameters and wave function of CePtSi3 by comparing those of other CeTX3(T: transition metal, X: Si, Ge) systems.

Intra-Individual Comparison between 2-D Shear Wave Elastography (GE System) and Virtual Touch Tissue Quantification (Siemens System) in Grading Liver Fibrosis

Ultrasound-based shear wave elastography (SWE) has recently gained substantial attention for non-invasive assessment of liver fibrosis. The purpose of this study was to perform an intra-individual comparison between 2-D shear wave elastography (2-D-SWE with a GE system) and Virtual Touch Tissue Quantification (VTTQ with a Siemens system) to assess whether these can be used interchangeably to grade fibrosis. Ninety-three patients (51 men, 42 women; mean age, 54 y) with liver disease of various etiologies (hepatitis B virus = 47, hepatitis C virus = 22; alcohol = 6, non-alcoholic steatohepatitis = 5, other = 13) were included. Using published system-specific shear wave speed cutoff values, liver fibrosis was classified into clinically non-significant (F0/F1) and significant (≥F2) fibrosis. Results indicated that intra-modality repeatability was excellent for both techniques (GE 2-D-SWE: intra-class correlation coefficient = 0.89 [0.84–0.93]; VTTQ: intra-class correlation coefficient = 0.90 [0.86–0.93]). Intra-modality classification agreement for fibrosis grading was good to excellent (GE 2-D-SWE: κ = 0.65, VTTQ: κ = 0.82). However, inter-modality agreement for fibrosis grading was only fair (κ = 0.31) using published system-specific shear wave speed cutoff values of fibrosis. In conclusion, although both GE 2-D-SWE and Siemens VTTQ exhibit good to excellent intra-modality repeatability, inter-modality agreement is only fair, suggesting that these should not be used interchangeably.

Band Offset Enhancement of a-Al2O3/Tensile-Ge for High Mobility Nanoscale pMOS Devices

The band alignment properties of amorphous Al2O3 on strain-engineered biaxial tensile-strained epitaxial Ge, grown in situ by molecular beam epitaxy on InxGa1–xAs virtual substrates, are presented. X-ray photoelectron spectroscopy investigation demonstrated an increase in the valence band offset of the Al2O3/strained Ge system with increasing tensile strain. For Ge strain-states of 1.14%, 1.6%, and 1.94%, the corresponding valence band offsets were found to be 4.43 ± 0.1 eV, 3.95 ± 0.1 eV, and 4.55 ± 0.1 eV, respectively, demonstrating a ~0.8 eV increase as compared with Ge grown on GaAs. The observed enhancement in the valence band discontinuity between tensile-strained Ge and Al2O3 offers a unique and novel path for the simultaneous improvement of hole mobility (via strain) and hole confinement (via a larger valence band offset) in future low-power and high-performance Ge-based nanoscale pMOS devices.

Prediction of saturation magnetostriction in solid-solution ternary alloys

A method for calculating saturation magnetostriction values in solid-solution ternary alloys is proposed using the magnetostriction data of binary alloys implicated in the ternary system and few data of ternary alloy. Studies on three systems are presented: the Fe–Al–Si system where a considerable magnetostriction data available in the literature was employed to perform the method; the Fe–Al–Ge system in which our data are compared and discussed with a previous study in this system; and the Fe–Ge–Si system for which iso-magnetostriction curves are proposed since only one experimental value in the literature was found. The results obtained by this method approximate previously reported experimental data. This can be used to design alloys with a defined value of magnetostriction reducing the number of samples and measurements or in calculations on theoretical models. In this sense, a hypothetical behaviour of magnetostriction in the Fe–Ge binary system for Ge > 20 at.%. is also presented.

ACROSS-SESSION REPRODUCIBILITY OF AUTOMATIC WHITE MATTER HYPERINTENSITIES SEGMENTATION: A EUROPEAN MULTI-SITE 3T STUDY

PharmaCOG is an industry-academic European project aimed at identifying reliable biomarkers that are sensitive to disease progression in patients with mild cognitive impairment. Several automated methods for quantitative assessment of white matter hyperintensities (WMH) have been recently developed (for a review see Caligiuri, 2015). However, the longitudinal reproducibility of these approaches has been poorly investigated. Here we present preliminary work aimed at evaluating the across-session test-retest reproducibility of the automated WMH quantification computed with SPM12 (Schmidt, 2012) on a group of healthy elderly subjects. Eleven 3T MRI sites (Siemens, GE, Philips) participated across Italy, Spain, France, Germany, Greece and The Netherlands. The acquisition protocol includes one 2D FLAIR sequence: acceleration factor in the range of 1.5 to 2 where possible (GRAPPA, SENSE and ASSET in Siemens, Philips and GE systems, respectively), 0.9x0.9x4mm3, with TE/TR/TI as recommended by the ADNI project (Jack, 2008). Five local healthy volunteers (55–90 years) per site were scanned in two sessions a week apart. The segmentation of WMH was performed using lesion segmentation tool (LST) version 2.0.15 (Schmidt, 2012) with optimized parameters and applying the longitudinal correction. The WMH volume and number of lesions reliability for each subject was computed evaluating test-retest absolute differences relative to the mean. Visual assessment indicates good segmentation results. The WMH volume was comparable across sites (Kruskal–Wallis, p=.143) and was around 1.6 ml (SD=2.9). The reproducibility error of total WMH volume averaged across sites was 2.3% (SD= 7.0) while that reported for the lesion number was 1.9% (SD=7.0). None of the WMH volume reproducibility metrics showed MRI site effects (Kruskall-Wallis test, p>.185). Despite the differences of MRI scanner configurations across our 11 sites we found consistent WMH volumes and lesion count reliability. Our findings suggest that the WMH volume may be a reliable longitudinal marker in multisite studies. Pharmacog is funded by the EU-FP7 for the Innovative Medicine Initiative (grant n°115009).

15 - Usefulness of longitudinal strain adjusted to regional thickness in hypertrophic cardiomyopathy

Background In hypertrophic cardiomyopathy (HCM), longitudinal strain analysis allows to early detect left ventricular (LV) contraction abnormalities despite preserved LV ejection fraction. In current software, the width of the region of interest (ROI) is the same over the entire myocardial wall and might analyze partially LV hypertrophic segments. Purpose The aim of this study is to evaluate a novel software for strain analysis with an adjustable ROI according to each segment thickness. Methods We included 110 patients: 55 patients with HCM (HCM group) and 55 healthy subjects (age- and sex-matched control group). All pts underwent echocardiography using a Vivid 9 GE system and measurements were performed using EchoPAC software. Global longitudinal strain (GLS) and regional strain for each of the 17 segments were calculated with standard software (for 2 groups) and with software adjusted to the myocardial wall thickness (for HCM group). Results GLS was significantly decreased in the HCM group as compared to the control group (−15.1 ± 4.8% versus–20.5 ± 4.3%, P Conclusion Analysis of longitudinal strain adjusted to regional thickness is feasible in HCM and allows a better evaluation of myocardial deformation, especially in the most LV hypertrophic segments.

Metric for strong intrinsic fourth-order phonon anharmonicity

Under the framework of Taylor series expansion for potential energy, we propose a simple and robust metric, dubbed ``regular residual analysis,'' to measure the fourth-order phonon anharmonicity in crystals. The method is verified by studying the intrinsic strong higher-order anharmonic effects in ${\mathrm{UO}}_{2}$ and ${\mathrm{CeO}}_{2}$. Comparison of the thermal conductivity results, which calculated by the anharmonic lattice dynamics method coupled with the Boltzmann transport equation and the spectral energy density method coupled with ab initio molecular dynamics simulation further validates our analysis. Analysis of the bulk Si and Ge systems confirms that the fourth-order phonon anharmonicity is enhanced and cannot be neglected at high enough temperatures, which agrees with a previous study where the four-phonon scattering was explicitly determined. This metric will facilitate evaluating and interpreting the lattice thermal conductivity of crystals with strong fourth-order phonon anharmonicity.

Detectability comparison between a high energy x-ray phase sensitive and mammography systems in imaging phantoms with varying glandular-adipose ratios

The objective of this study was to demonstrate the potential benefits of using high energy x-rays in comparison with the conventional mammography imaging systems for phase sensitive imaging of breast tissues with varying glandular-adipose ratios.This study employed two modular phantoms simulating the glandular (G) and adipose (A) breast tissue composition in 50 G–50 A and 70 G–30 A percentage densities. Each phantom had a thickness of 5 cm with a contrast detail test pattern embedded in the middle. For both phantoms, the phase contrast images were acquired using a micro-focus x-ray source operated at 120 kVp and 4.5 mAs, with a magnification factor (M) of 2.5 and a detector with a 50 µm pixel pitch. The mean glandular dose delivered to the 50 G–50 A and 70 G–30 A phantom sets were 1.33 and 1.3 mGy, respectively. A phase retrieval algorithm based on the phase attenuation duality that required only a single phase contrast image was applied. Conventional low energy mammography images were acquired using GE Senographe DS and Hologic Selenia systems utilizing their automatic exposure control (AEC) settings. In addition, the automatic contrast mode (CNT) was also used for the acquisition with the GE system. The AEC mode applied higher dose settings for the 70 G–30 A phantom set. As compared to the phase contrast images, the dose levels for the AEC mode acquired images were similar while the dose levels for the CNT mode were almost double.The observer study, contrast-to-noise ratio and figure of merit comparisons indicated a large improvement with the phase retrieved images in comparison to the AEC mode images acquired with the clinical systems for both density levels. As the glandular composition increased, the detectability of smaller discs decreased with the clinical systems, particularly with the GE system, even at higher dose settings. As compared to the CNT mode (double dose) images, the observer study also indicated that the phase retrieved images provided similar or improved detection for all disc sizes except for the disk diameters of 2 mm and 1 mm for the 50 G–50 A phantom and 3 mm and 0.5 mm for the 70 G–30 A phantom.This study demonstrated the potential of utilizing a high energy phase sensitive x-ray imaging system to improve lesion detection and reduce radiation dose when imaging breast tissues with varying glandular compositions.

Characterisation of noise and sharpness of images from four digital breast tomosynthesis systems for simulation of images for virtual clinical trials

In-depth evaluation of the noise and sharpness characteristics of FujiFilm Innovality, GE SenoClaire, Hologic Selenia Dimensions and Siemens Inspiration digital breast tomosynthesis (DBT) systems was performed with the intention of improving image simulation for virtual clinical trials. Noise power spectra (NPS) and modulation transfer function curves (MTF) were measured for planar modes and for the first and central projections for DBT modes. In DBT mode, the x-ray beam was blocked for the projections before the central projection in order to remove the influence of lag and ghosting from the previous images. A quadratic fit between the NPS and linearised pixel value gave the noise coefficients for planar and DBT imaging modes. The spatial frequencies corresponding to an MTF of 0.5 (MTF0.5) were calculated from the MTF measurements made on the breast support and at 40 mm above the breast support. This was done for the first and the central projections. The percentage of signal carried over from the first projection to subsequent images (lag) was measured using a slit. The noise associated with lag was also evaluated. The DBT modes typically had lower electronic noise coefficients but higher structural noise coefficients compared to the respective planar mode MTF0.5 measured 40 mm above the table was between 6% and 47% lower for continuous scanning systems compared to 1% lower for step and shoot systems. For wide angle DBT, the MTF0.5 of the first projection was 18% (FujiFilm) and 28% (Siemens) lower than for the central projection. Lag in the second projection was 2.2%, 0.3%, 0.8% for the FujiFilm, GE and Hologic systems respectively. In all cases, the noise associated with lag was negligible. Current modelling frameworks for virtual clinical trials of breast DBT systems need to be adapted to account for signals from lag and variations in the MTF at wide angles.

2D Tl–Pb compounds on Ge(1 1 1) surface: atomic arrangement and electronic band structure

Structural transformations and evolution of the electron band structure in the (Tl, Pb)/Ge(1 1 1) system have been studied using low-energy electron diffraction, scanning tunneling microscopy, angle-resolved photoelectron spectroscopy and density functional theory calculations. The two 2D Tl–Pb compounds on Ge(1 1 1), -(Tl, Pb) and -(Tl, Pb), have been found and their composition, atomic arrangement and electron properties has been characterized. The (Tl, Pb)/Ge(1 1 1) compound is almost identical to the alike (Tl, Pb)/Si(1 1 1) system from the viewpoint of its atomic structure and electronic properties. They contain 1.0 ML of Tl atoms arranged into a honeycomb network of chained trimers and 1/3 ML of Pb atoms occupying the centers of the honeycomb units. The (Tl, Pb)/Ge(1 1 1) compound contains six Tl atoms and seven Pb atoms per unit cell (i.e. ∼0.67 ML Tl and ∼0.78 ML Pb). Its atomic structure can be visualized as consisting of Pb hexagons surrounded by Tl trimers. The (Tl, Pb)/Ge(1 1 1) and (Tl, Pb)/Ge(1 1 1) compounds are metallic and their band structures contain spin-split surface-state bands. By analogy with the (Tl, Pb)/Si(1 1 1), these (Tl, Pb)/Ge(1 1 1) compounds are believed to be promising objects for prospective studies of superconductivity in one-atom-layer systems.

Strain relaxation of CdTe on Ge studied by medium energy ion scattering

We have used the medium energy ion scattering (MEIS) technique to assess the strain relaxation in molecular-beam epitaxial (MBE) grown CdTe (211)/Ge (211) system. A previous X-ray diffraction study, on 10 samples of the same heterostructure having thicknesses ranging from 25nm to 10μm has allowed the measurement of the strain relaxation on a large scale. However, the X-ray diffraction measurements cannot achieve a stress measurement in close proximity to the CdTe/Ge interface at the nanometer scale. Due to the huge lattice misfit between the CdTe and Ge, a high degree of disorder is expected at the interface. The MEIS in channeling mode is a good alternative in order to profile defects with a high depth resolution. For a 21nm thick CdTe layer, we observed, at the interface, a high density of Cd and/or Te atoms moved from their expected crystallographic positions followed by a rapid recombination of defects. Strain relaxation mechanisms in the vicinity of the interface are discussed

SU‐F‐J‐171: Robust Atlas Based Segmentation of the Prostate and Peripheral Zone Regions On MRI Utilizing Multiple MRI System Vendors

Purpose:Automatically generated prostate MRI contours can be used to aid in image registration with CT or ultrasound and to reduce the burden of contouring for radiation treatment planning. In addition, prostate and zonal contours can assist to automate quantitative imaging features extraction and the analyses of longitudinal MRI studies. These potential gains are limited if the solutions are not compatible across different MRI vendors. The goal of this study is to characterize an atlas based automatic segmentation procedure of the prostate collected on MRI systems from multiple vendors.Methods:The prostate and peripheral zone (PZ) were manually contoured by an expert radiation oncologist on T2‐weighted scans acquired on both GE (n=31) and Siemens (n=33) 3T MRI systems. A leave‐one‐out approach was utilized where the target subject is removed from the atlas before the segmentation algorithm is initiated. The atlas‐segmentation method finds the best nine matched atlas subjects and then performs a normalized intensity‐based free‐form deformable registration of these subjects to the target subject. These nine contours are then merged into a single contour using Simultaneous Truth and Performance Level Estimation (STAPLE). Contour comparisons were made using Dice similarity coefficients (DSC) and Hausdorff distances.Results:Using the T2 FatSat (FS) GE datasets the atlas generated contours resulted in an average DSC of 0.83±0.06 for prostate, 0.57±0.12 for PZ and 0.75±0.09 for CG. Similar results were found when using the Siemens data with a DSC of 0.79±0.14 for prostate, 0.54±0.16 and 0.70±0.9. Contrast between prostate and surrounding anatomy and between the PZ and CG contours for both vendors demonstrated superior contrast separation; significance was found for all comparisons p‐value &lt; 0.0001.Conclusion:Atlas‐based segmentation yielded promising results for all contours compared to expertly defined contours in both Siemens and GE 3T systems providing fast and automatic segmentation of the prostate.Funding Support, Disclosures, and Conflict of Interest: AS Nelson is a partial owner of MIM Software, Inc. AS Nelson, and A Swallen are current employees at MIM Software, Inc.

Representation of type I heterostructure junctionless tunnel field effect transistor for high-performance logic application

In this paper, a gate-all-around junctionless tunnel field effect transistor (JLTFET) based on heterostructure of compound and group III–V semiconductors is introduced and simulated. In order to blend the high tunneling efficiency of narrow band gap material JLTFETs and the high electron mobility of III–V JLTFETs, a type I heterostructure junctionless TFET adopting Ge–AlxGa1−xAs–Ge system has been optimized by numerical simulation in terms of aluminum (Al) composition. To improve device performance, we considered a nanowire structure, and it was illustrated that high-performance logic technology can be achieved by the proposed device. The optimal Al composition founded to be around 20 % (x = 0.2). The numerical simulation results demonstrate that the proposed device has low leakage current IOFF of ~1.9 × 10−17, ION of 4 µA/µm, ION/IOFF current ratio of 1.7 × 1011 and subthreshold swing SS of 12.6 mV/decade at the 40 nm gate length and temperature of 300 K.

Germanium–tin interdiffusion in strained Ge/GeSn multiple-quantum-well structure

The thermal stability and germanium–tin (Ge–Sn) interdiffusion properties were studied in epitaxial Ge/GeSn multiple-quantum-well (MQW) structure. No obvious interdiffusion was observed for annealing temperatures of 300 °C or below, while observable interdiffusion occurred for annealing temperatures of 380 °C and above. High-resolution x-ray diffraction was used to obtain the interdiffusion coefficient by analyzing the decrease rate of Ge/GeSn periodic satellite peaks. The interdiffusion coefficient is much higher, and the activation enthalpy of 1.21 eV is substantially lower in Ge/GeSn MQW structure than that previously reported in silicon–germanium (Si–Ge) systems. When the annealing temperature is increased to above 500 °C, Ge–Sn interdiffusion becomes severe. Some small pits appear on the surface, which should be related to Sn out-diffusion to the Ge cap layer, followed by Sn desorption from the top surface. This work provides insights into the Ge–Sn interdiffusion and Sn segregation behaviors in Ge/GeSn MQW structure, and the thermal budget that may be used for fabrication of devices comprising Ge/GeSn heterostructures.

0553 : Assessment of myocardial deformation using multi-layer speckle tracking in patients undergoing chemotherapy: a comparison of two vendors

The purpose of this study was to investigate intervendor variability when measuring multilayer strain in cancer patients treated with oral chemotherapy. Patients enrolled to receive oral chemotherapy were prospectively included. Firstly, a same operator performed a 2 dimensional echocardiography within a delay of 10 minutes using Vivid 9 (Vendor A) and SC 2000 Siemens (Vendor B) ultrasound systems for each patient. Thereafter, we assessed myocardial deformation by using their respective speckle tracking softwares for strain multilayer measurement. Thus, we compared GLS multilayer values for the 2 vendors in each apical view (4c, 3c and 2c) and for each layer (endocardial, mid and epicardial layer). Comparisons between the 2 vendors were evaluated using intra class correlation coefficient. Eighty patients planned to receive chemotherapy were prospectively included between February and June 2015. Mean age was 55.3±16.3 years and 61% were female. Median left ventricular ejection fraction was 62% (57-66). Results of GLS multilayer values according to vendor, incidence, layer and their comparison are summarized in Table 1 There was a poor agreement between GLS multilayer as measured with GE system and Siemens system, whatever the layers, the incidence and the vendor. We found a poor agreement for layer specific strain evaluation between GE and Siemens system using their dedicated softwares for strain multilayer assessment. These results suggest that in patient receiving chemotherapy the same system and software from the same vendor should be used for a longitudinal follow-up. The author hereby declares no conflict of interest Table Values of GLS according to vendor, layer and views Vendor A Vendor B ICC±SD 4c GLS endo 20.7 (18.5-23.5) 18.8 (17.1-21.0) 0.315±0.089 4c GLS mid 18.2 (16.1-20.5) 15.5 (13.6-17.2) 0.222±0.075 4c GLS epi 15.9 (14.1-17.9) 11.8 (10.6-14.2) 0.125±0.055 3c GLS endo 22.2 (19.8-25.7) 18.5 (16.6-21.4) 0.310±0.078 3c GLS mid 19.2 (17.3-22.3) 15.1 (13.6-17.5) 0.291±0.061 3c GLS epi 16.9 (15.2-14.2) 12.0 (9.6-13.5) 0.189±0.045 2c GLS endo 21.7 (19.0-24.1) 18.0 (16.7-20.9) 0.234±0.075 2c GLS mid 19.3 (17.0-21.8) 15.3 (13.2-17.1) 0.180±0.057 2c GLS epi 17.3 (15.1-19.4) 12.0 (10.3-14.0) 0.042±0.040 GLS: Global longitudinal strain, 4c: 4 chamber view, 3c: 3 chamber view, 2c: 2 chamber view, endo: endocardial layer, mid: mid layer, epi: epicardial layer, ICC: intraclass correlation coefficient, SD: Standard deviation.