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Aims Reduced muscle endurance (RME) in patients with HFpEF and HFrEF is associated with structural and metabolic changes in skeletal muscle. We investigated the role of kynurenine (Kyn) as a potential marker in detecting RME. Additionally, we described the likely distorted metabolic pathways in serum in patients with RME and both preserved (HFpEF) and reduced (HFrEF) ejection fraction. Methods Fifty-five participants were prospectively recruited (17 HFpEF, 18 HFrEF outpatients and 20 healthy controls, HC). All participants underwent echocardiography, CPET, isokinetic muscle function tests. Quantification of metabolites in serum was performed using liquid chromatography tandem mass spectrometry. Results In a linear regression, Kyn was an independent predictor for RME after adjusting for alanine, glutamate, ornithine, spermine and short-chain-ACs (B: −8.2 per 1μM increase, 95% CI: −13.01, −3.30, p=0.001). Kyn showed 83% sensitivity and 70% specificity (area under the curve 0.83) in detecting RME. Patients with RME and HFpEF showed reduced levels of long-chain-, medium-chain-, medium-/long-chain-ACs ratios and alanine (p Conclusions Kyn shows high potential as biomarker for detecting RME. RME was associated with impaired fatty acid oxidation rates in HFpEF patients and with reduced concentrations of AAs in those with HFrEF. Funding Acknowledgement Type of funding sources: None.

The paper investigates the effect of pedestal turbulence, i.e. coherent mode (CM), on the divertor total particle flux, the particle flux distribution and heat flux distribution, and their decay lengths in the scrape-off layer (SOL) region on EAST tokamak. The experimental evidence indicates the coherence between the pedestal CM and the divertor particle flux fluctuation, which implies that the pedestal CM can affect the divertor plasma behavior. The increase of the particle flux decay length ( λ j s ) correlates with the density radial decay length (λ n,SOL) in the SOL region where the λ n,SOL is largely affected by the change of pedestal CM amplitude. A quantitative statistical analysis shows that the divertor total particle flux and λ j s in the SOL region increase with increasing amplitude of the electron density fluctuation and the electron temperature fluctuation induced by the pedestal CM. The temporal decay process of the total particle flux is interrupted by the appearance of CM at the pedestal. Meanwhile, the spatial distributions of the divertor particle flux and heat flux are enhanced when the pedestal CM appears, which are observed in both the upper single null and lower single null configurations.

The I-mode is a promising operation mode for fusion in the future, featuring high-temperature and low-density confinement, but the reason why the temperature and density are decoupled remains an important aspect to be explored. The experimental results from the experimental advanced superconducting tokamak (EAST) showed that the weakly coherent mode (WCM) is directly related to sustaining the I-mode and that the peak amplitude of the WCM is proportional to the temperature in the pedestal. Simulating the experimental data from EAST with the six-field model of BOUT++, we find a density perturbation close to the frequency of the WCM observed in the experiment. By testing all the physical terms in this model, we find that the density perturbation and particle transport are directly related to the drift Alfvén wave (DAW) mode. We also use the SymPIC program (Xiao et al Plasma Sci. Technol. 20 110501; Phys. Plasmas 22 112504; Plasma Sci. Technol. 23 055102) to simulate the same experimental data and find that the frequency range of the WCM is close to both experimental and BOUT++ results. Therefore, the WCM of the I-mode can be considered to be driven by the DAW, which helps improve the transport of the I-mode.

Theory-based integrated modeling is validated against high-performance steady-state core plasmas on EAST in the high poloidal beta (β p) regime with only RF heating. Reasonably good agreement between the modeling results and experimental measurements is obtained not only for the temperature profiles but also for the 11-chord line-integrated densities and Faraday angles for the first time. This validation effort demonstrates that the safety factor profiles can be non-reversed in high β p experiments on EAST. The inaccessibility for LH waves observed in conventional ray-tracing simulations for some high β p experiments is effectively mitigated by including the modeling of wave propagation in the scrape-off layer. The observed confinement improvement with density increasing (Gong et al 2019 Nucl. Fusion 59 086030) can be attributed to the reduction of turbulent transport by the collisional stabilization in trapped electron modes, rather than by the Shafranov shift stabilization effect which was proposed to be the major cause of confinement enhancement in previous literature. Based on the successful validation and newly gained physical insights, predictive modeling is performed for core plasma considering the future upgrade capacity of LH wave system and shows that the high-performance steady-state H-mode scenario on EAST can be extended to the regime with q 95 to be ITER relevant.

The dynamics of electron-internal transport barrier (e-ITB) formation is studied in the hybrid plasma of neutral beam injection and lower hybrid wave heating on EAST. The e-ITB is observed to be repetitively formed at the H–L transition, where the relaxation process of core radiation triggers an increase in neutron yield and core electron temperature. A reversed q-profile is beneficial for generating the barrier, identified by the appearance of reversed shear Alfvén eigenmodes (RSAEs). The dimensionless parameter of the normalized Larmor radius ( ρ T e * ) is estimated to visualize the dynamic behavior of the e-ITB. It is found that the e-ITB forms once the electron ρ T e * exceeds 0.014, and the RSAEs are accompanied by the e-ITB formation. The barrier foot moves inwards until the L–H transition occurs, where the H-mode pedestal or type-I edge localized mode (ELM) strongly influences the e-ITB intensity. The results of thermal transport modeling show a significant reduction in the core thermal transport coefficient in the electron channel while maintaining a nearly unchanged ion transport level as the e-ITB evolves.

In order to study the generation and extraction of negative ions for neutral beam injection application, a negative ion source is being designed and constructed at Institute of Plasma Physics, Chinese Academy of Sciences (ASIPP). Through a four electrode grids system inside the accelerator, a negative ion beam will be extracted and accelerated up to −60 kV on a reduced scale extraction area of 12 × 50 cm 2 (the area of PG apertures is 185 cm 2 ). The beam optics is a key issue for the accelerator design, and greatly determine the source experimental performance in term of beam current, heat load on the grid, beam divergence, and so on. In this paper, the trajectories of electrons and negative ions were simulated in the electrode grids of the negative ion source. The filter capability of electron deflection magnet on the co-extracted electrons is evaluated and confirmed. The negative ion beam optics was designed according to the calculated results of beam divergence and beam radius along the beamlet in different acceleration voltages. The deflection effect of the electron deflection magnet on the negative ion beam was investigated in the single beamlet case and multi-beamlets case.

In order to accumulate the research experience and technical reserves for future negative ion sources of nuclear fusion reactors, a prototype negative ion source is being designed and constructed at ASIPP with a reduced scale extraction area (166 cm2 on the opening of 12 × 48 cm2). Based on the existing negative ion sources having the similar width, an external magnetic filter with permanent magnets is applied to the prototype negative ion source during the initial experiments. For the specific experiments of magnetic field dependence, an adjustable magnetic filter is required. Hence, the plasma grid current filter for short-pulse or long-pulse source and a combination filter using permanent magnets and plasma grid current are designed. The main design purpose is to produce a homogenous and sufficient filter field in front of the plasma grid, with the supply current as low as possible. The filter field distributions of these different magnetic filters are studied in detail by finite element method, especially on the plane paralleling with the plasma grid.

As current technology development trend of microelectronic industry driven by portable and wearable electronic products, adopting advanced IC fabrication process technology and a powerful integrated fan-out (InFO) wafer level system integration (WLSI) technology has been developed to integrate application processor chip with memory package for smart mobile devices[1][3]. This fan-out wafer level package (FO-WLP) to extend the functionality performance within thin form-factor for fulfilling product application requirements is essential and important to a successful new product development, especially for Application Processor, Field Programmable Gate Array (FPGA) and power management IC (PMIC) products[1]. FO-WLP is good electrical performance package by its very short distance package level interconnection, and it has been rapidly adopted for 12 inch copper fabrication process technologies. Knowing its very thin package without package substrate as stress buffer between IC chip and system board, board level reliability performance of FO-WLP becomes challenge as products moving to large die size for enabling more functionality on the same or less space due to higher package stress induced by larger die size[2]. The board level underfill(UF) has been implemented in Surface Mount Technology(SMT) assembly process to prevent mechanical stress induced solder ball and redistribution layer (RDL) damage[4]. In general, the UF will help to reduce the mechanical stress to impact solder joint reliability. However, due to less sophistication of SMT UF process compared with flip-chip assembly UF process, such as no pre-plasma treatment, high dispensing speed and no CSAM inspection to detect the dispensing quality, SMT UF dispensing quality brings a great of quality and reliability concern to the FO-WLP package joint on board, especially electrical leakage issue due to small ball pitch of the package. Therefore, it becomes the objective of this study on SMT production quality and reliability risk of FO-WLP package on board with focusing on board level UF filling into BGA balls of FO-WLP package impact to product reliability.

The low-frequency optical absorption properties of graphene nanoribbons in a composite magnetic field are investigated by using the gradient approximation. The spectral function exhibits symmetric delta-function like prominent peaks structure in a uniform magnetic field, and changes to asymmetric square-root divergent peaks structure when subjecting to a composite field. These asymmetric divergent peaks can be further classified into principal and secondary peaks. The spectral intensity and frequency of the absorption peaks depend sensitively on the strength and modulation period of the composite field. The transition channels of the absorption peaks are also analyzed. There exists an optical selection rule which is caused by the orthogonal properties of the sublattice wave functions. The evolution of the spectral frequency of the absorption peaks with the field strength is explored.

Rationale: The contribution of bone marrow–borne hematopoietic cells to the ischemic myocardium has been documented. However, a pivotal study reported no evidence of myocardial regeneration from hematopoietic-derived cells. The study did not take into account the possible effect of early injury–induced signaling as the test mice were parabiotically paired to partners immediately after surgery-induced myocardial injury when cross-circulation has not yet developed. Objective: To re-evaluate the role of circulating cells in the injured myocardium. Methods and Results: By combining pulse-chase labeling and parabiosis model, we show that circulating cells derived from the parabiont expressed cardiac-specific markers in the injured myocardium. Genetic fate mapping also revealed that circulating hematopoietic cells acquired cardiac cell fate by means of cell fusion and transdifferentiation. Conclusions: These results suggest that circulating cells participate in cardiomyocyte regeneration in a mouse model of parabiosis when the circulatory system is fully developed before surgery-induced heart injury.

During the process of beam extraction in positive ion source under high voltage region, a large number of electrons are produced in the gaps of grids. After back-streaming acceleration, these electrons go back to arc chamber or impinge grids and heat electron dump or grids, which are harmful for the safety of ion source. Under the situation of poor beam extraction optics, a large part of the primary beam ions bombard the surface of suppressor grid. And this process produces a large number of electrons. Due to the huge extracted voltage, the secondary electron emission coefficient of the suppressor grid surface is also great, when beam ions bombard on it. As a result, the grids’ current grows. The curvature of ion emission surface and equipotential surface nearby are mainly connected to the perveance and plasma grid geometry. In order to optimize the beam performance of high current ion source and increase the mean arc efficiency, the plasma grid of accelerator is already replaced from circular cross section grid to diamond cross section grid. As a result, the shape of ion emission surface is only connected to the perveance. According the measurement of the current of suppressor grid and the calculation of the perveance of the corresponding shoot, we can analyze the effect of beam divergence angle on back-streaming electron. When the beam divergence angle increases, the number of back-streaming electrons increases rapidly, and grids current changes significantly, especially the current of gradient grid and suppressor grid. The results can guide the parameters operating on the ion source for EAST-NBI and find the reasonable operation interval of perveance and the best one to ensure the safety and stable running of the ion source, which has great significance on the development of long pulse, high power ion source.

The reflectometry diagnostics on experimental advanced superconducting tokamak (EAST) are composed of Q-band (32–56 GHz), V-band (48–76 GHz) and W-band (72–110 GHz) microwave reflectometers with X-mode polarization. The three reflectometers with separate frequency bands were launched independently in previous experiments and now are combined together by applying advanced microwave technology. A quasi-optical (QO) combiner/de-combiner by using frequency selective surfaces (FSSs) has been built to combine the three bands so that these waves (32–110 GHz) can be transmitted to the antenna by using one single oversized waveguide. Two double-ridged horns are used for launcher and receiver. The received waves are decoupled by using a QO de-combiner, the same with the combiner. The designed parameters and laboratory test results of the upgraded system have been presented. The density pedestal evolution during the edge localized modes (ELMs) in EAST plasma have been presented as an example for the application of the updated reflectometers.

A cross-scale interaction between a kink instability with toroidal mode number (n) of 1 and background microturbulence (mainly a coherent mode with n = 12–17) has been observed in the H-mode edge pedestal region in the EAST tokamak. The n = 1 kink mode with a frequency ~3.5 kHz is localized in the pedestal region. The amplitude of pedestal microturbulence is evidently modulated at the frequency of the n = 1 mode. This amplitude modulation is mainly for the fluctuation component with frequency less than 100 kHz, while no modulation by the n = 1 mode is observed for the component with frequency larger than 100 kHz. This implies that the observed amplitude modulation by the n = 1 mode is not due to the Doppler shift effect. A further analysis shows that the amplitude modulation of microturbulence could be attributed to modulation of the local temperature gradient by the n = 1 kink mode. In addition, bicoherence analysis indicates that there exists a possible direct nonlinear interaction between background microturbulence and the n = 1 kink instability. A preliminary analysis shows that this cross-scale interaction has no evident effect on the pedestal structure.

Rutherford backscattering and channeling is combined with X-ray diffraction to study the depth dependence of crystalline quality in InN layers grown by metalorganic chemical vapor deposition on sapphire substrate. The poorest crystalline quality in InN layer is produced at the intermediate region over 100 nm away from the InN/sapphire interface. With increasing layer thickness the crystalline quality improves to a certain degree dependent on the growth temperature. The InN sample grown at 450 °C is found to be more homogeneous than the sample grown at 550 °C. The difference in the defect profile is explained by the temperature-dependent growth modes. The inhomogeneity of structural quality and related properties such as carrier concentration and strain field is possibly the reason to observe a high energy wing in PL spectrum of the InN sample grown at 550 °C.

The in-plane orientation of epitaxial ZnO thin film on Al2O3(0 0 0 1) was determined by azimuthal scan of X-ray diffraction. Comprehensive structural characterizations, including the lattice strain in perpendicular direction, the defect density, were obtained from high resolution X-ray diffraction. It's found that a 30° rotation in ZnO against Al2O3, resulting in ZnO〈1 1 2 0〉//Al2O3〈1 0 1 0〉, can efficiently reduce the strain and defects in ZnO layer. Consequently, the optical property is significantly improved.

High-quality AlInGaN quaternary layers were grown on c-Al2O3 using a thick GaN template. A full width at half maximum of 0.075 degrees from AlInGaN(0004) rocking curve and a minimum yield of 5.6% from Rutherford backscattering/channelling spectrometry (RBS) prove the AlInGaN layer of a comparable crystalline quality with GaN layers. The chemical compositions (both of Al and In contents) of AlInGaN layers are directly obtained from RBS and elastic recoil detection analysis. The lattice parameters both in perpendicular and parallel directions are deduced from X-ray diffraction. The AlInGaN layer is found to process a compressive strain in parallel direction and a tensile strain in perpendicular direction. (c) 2006 Elsevier B.V. All rights reserved.

We report on structural characterization of AlGaN/GaN superlattices grown on sapphire. The superlattice formation is evidenced by high-resolution x-ray diffraction and transmission electron microscopy. The high resolution x-ray diffraction spectra exhibit a pattern of satellite peaks. The in-plane lattice constants of the superlattices indicate the coherent growth of the AlGaN layer onto GaN. The average At composition in the superlattices is determined to be 0.08 by Rutherford backscattering spectroscopy. The average parallel and perpendicular elastic strains for the SLs are determined to be (e(parallel to)) = +0.25% and (e(perpendicular to)) = -0.17%. (c) 2006 Elsevier Ltd. All rights reserved.

Rutherford backscattering/channeling (RBS/C) and X-ray diffraction (XRD) are used to comprehensively characterize a heterostructure of AlInGaN/GaN/Al2O3(0001). The AlInGaN quaternary layer was revealed to process a high crystalline quality with a minimum yield of 1.4% from RBS/C measurements. The channeling spectrum of (1 (2) under bar 13) exhibits higher dechanneling than that of (0001) at the interface of AlInGaN/GaN. XRD measurements prove a coherent growth of AlInGaN on the GaN template layer. Combining RBS/C and XRD measurements, we found that the interface of GaN/Al2O3 is a nucleation layer, composed of a large amount of disorders and cubic GaN slabs, while the interface of AlInGaN/GaN is free of extra disordering (i.e. compare with the GaN layer). The conclusion is further evidenced by transmission electron microscopy (TEM). (c) 2005 Elsevier Ltd. All rights reserved.

The strain state of 570nm AlXGa1-xN layers grown on 600nm GaN template by metal organic chemical vapor deposition was studied using Rutherford backscattering (RBS)/channeling and triple-axis X-ray diffraction measurements. The results showed that the degree of relaxation (R) of AlxGa1-xN layers increased almost linearly when x less than or equal to 0.42 and reached to 70% when x = 0.42. Above 0.42, the value of R varied slowly and AI(x)Ga(1-x)N layers almost full relaxed when x = 1 (AIN). In this work the underlying GaN layer was in compressive strain, which resulted in the reduction of lattice misfit between GaN and AlxGa1-xN, and a 570nm AlxGa1-xN layer with the composition of about 0.16 might be grown on GaN coherently from the extrapolation. The different shape of (0004) diffraction peak was discussed to be related to the relaxation. (C) 2004 Elsevier B.V. All rights reserved.

In this paper, an approach to determine the average In composition in InGaN/GaN multiple quantum wells (MQWs) was suggested. The period thickness and the average lattice constants (〈aepi〉 and 〈cepi〉) of MQWs were calculated from high-resolution X-ray diffraction (HRXRD). Then by applying the Vegard's law, the average In composition 〈x〉 was simultaneously determined by considering the relationship between the lattice constants under strain. At the same time, by using the period thickness, the average In composition was obtained from the simulation of the Rutherford backscattering spectroscopy (RBS). The results obtained from the two techniques are agreeable. So the approach of combining both HRXRD and RBS can tell reliable chemical composition in InGaN/GaN MQWs.

The objective of this study was to examine the effects of follicular cells on the in vitro development of porcine preantral follicles. In Experiment 1, one preantral follicle alone (Trt 1) was cocultured with a follicle of the same size with oocytes (Trt 2) or without oocytes (Trt 3). Preantral follicles cultured alone in vitro for 12 days had greater follicle diameters (1017 +/- 96 microm versus 706 +/- 69 or 793 +/- 72 microm, P0.05), growth rates (201 +/- 0.3 versus 103 +/- 0.2 or 128 +/- 0.2, P0.05) and oocyte survival rates (73% versus 48, or 25%, P0.05) than other groups. The inhibitory effects of follicle cells on the growth of preantral follicles and oocyte survival rates were not enhanced by the addition of oocytectomized preantral follicles (Experiment 2). Follicles were cocultured with different sources of follicular cells in other experiments. Coculture with cumulus cells enhanced oocyte survival compared to the control (without coculture) and mural follicular cell groups (Experiment 3). The growth and survival rates of oocytes collected from the group of follicles cocultured with cumulus cells from large antral follicles (3 mm) were greater (P0.05) than those from small antral follicles (3 mm), or than the control group (without cumulus cells, experiment 4). No significant differences in the follicular diameters (674 +/- 30 microm versus 638 +/- 33 and 655 +/- 28 microm) and growth rate (105% versus 94 and 105%) were observed among the preantral follicles of the different treatments (P0.05). Taken together, coculture with the cells from large antral follicles (3 mm) exerted a significant positive effect on oocyte survival. The growth and oocyte survival of preantral follicle cocultured with the same size of follicles (with or without oocyte) were inhibited. Growth and survival rates of preantral follicles and oocytes are improved by coculturing them with the cumulus cells derived from larger antral follicles.

A thin AlGaN layer, which is suitable for structural study using Rutherford backscattering (RBS)/channeling, was grown on an Al2O3(0 0 0 1) substrate by metalorganic chemical vapor deposition. The results show that the composition of the epilayer is Al0.05Ga0.95N and that although the epilayer is very thin (79 nm), it has a good crystalline quality (χmin=1.9%). The azimuthal orientation of the AlGaN epilayer relative to the Al2O3 substrate is AlGaN[0 0 0 1] // Al2O3[0 0 0 1] and AlGaN {1 1 2 0} // Al 2 O 3 {1 0 1 0} , showing that the AlGaN epilayer is rotated by 30° around the [0 0 0 1] axis with respect to the Al2O3 substrate which decreases the lattice mismatch between the epilayer and the substrate significantly. RBS angular scan was used to determine the strain-induced tetragonal distortion of the epilayer. Combined with X-ray diffraction, the perpendicular and parallel elastic strains of the AlGaN layer, e⊥=+0.31% and e∥=−0.28%, can be calculated.

InGaN and AlGaN layers were grown on Al2O3 substrate by metalorganic chemical vapor deposition (MOCVD) with a GaN intermediate layer. The thickness and the composition of the layers, 270 nm In0.18Ga0.82N and 765 nm Al0.28Ga0.72N, were determined by Rutherford backscattering (RBS). The elastic strain of these layers was determined by X-ray diffraction combined with RBS/channeling. The results show that these layers are partially strained with a perpendicular strain e⊥=+0.21%, parallel strain e||=−0.53% for the InGaN layer and e⊥=−0.16%, e||=+0.39% for the AlGaN layer. The signs of e|| and e⊥ of AlGaN are opposite to those of InGaN, since the lattice mismatch between AlGaN and GaN is negative while the lattice mismatch between InGaN and GaN is positive.

The ternary silicide, Er0.5Y0.5Si1.7 has been produced by channeled ion beam synthesis (CIBS) in a Si(1 1 1) substrate. The properties of the material have been compared with those of the binary silicides (i.e. ErSi1.7 and YSi1.7) produced by the same method. Analysis was carried out using Rutherford backscattering (RBS) and X-ray diffraction (XRD). The study revealed that the layer produced is of good crystalline quality, and is indeed composed of the Er0.5Y0.5Si1.7 ternary silicide as opposed to a mixture of the two binaries. It is epitaxial with respect to the Si substrate and possesses the same hexagonal (AlB2) structure exhibited by both binary silicides. The azimuthal orientation with respect to the substrate is Er0.5Y0.5Si1.7[0 0 0 1]//Si[1 1 1] and Er0.5Y0.5Si1.7{1 1 2 0}//Si{1 1 0}. The epilayer was found to be elastically strained with the perpendicular strain=−0.67% and the parallel strain=+0.34% similar to the values found for the Er and Y silicides.

A buried hexagonal YSi 1.7 layer is formed by channelled implantation of Y ions into (1 1 1) oriented silicon wafers. The orientation relationship between the epitaxial YSi 1.7 and the silicon is (0 0 0 1) YSi 1.7 ‖(1 1 1) Si with 〈1 1 2 0〉 YSi 1.7 ‖〈1 1 0〉 Si . Annealing at 600°C for 1 h and subsequently at 1000°C for 0.5 h improves the crystalline quality of the buried YSi 1.7 layer. On the other hand, Nd-disilicide cannot be grown epitaxially on a Si(1 1 1) substrate. However, by using a sequential implantation of Y and Nd ions, a buried hexagonal Nd 0.32 Y 0.68 Si 1.7 layer with good crystalline quality is formed in the Si(1 1 1) substrate.

Epitaxial ternary silicide Er0.49Gd0.51Si1.7 layers with a good crystalline quality (χmin of Er and Gd is 3.7%) have been formed by 60 keV Er and Gd ion implantation into Si(1 1 1) substrates to a total dose of 1.0 × 1017/cm2 at 450°C using channeled ion beam synthesis (CIBS). The composition, the structure, the strain and the thermal stability of these layers have been studied using energy dispersive spectroscopy (EDS), Rutherford backscattering (RBS)/channeling and X-ray diffraction (XRD). It is shown that the perpendicular and parallel elastic strains of the Er0.49Gd0.51Si1.7 epilayer are e⊥=−0.46% ± 0.02% and e‖=+0.73% ± 0.19%. The layer is stable up to 900°C. Annealing at 950°C results in a phase transformation.

Si(111) substrates were implanted with 70 or 90 keV 166 Er atoms to doses from 1.3 to 2.0×10 17 cm −2 at substrate temperatures from 450 to 530°C. During implantation, the Si substrates were tilted by 7° to minimize the channeling effect. The Er silicide layers formed under these conditions are not as good as Co silicide layers formed by Co implantation under similar conditions and the reason is discussed. One of the best results is an annealed sample containing a discontinuous epitaxial ErSi 1.7 layer with χ min of 40%. Rutherford backscattering and channeling spectrometry, X-ray diffraction and transmission electron microscopy have been used to study this heteroepitaxial ErSi 1.7 layer, showing that the epilayer is compressively strained and the azimuthal orientation of the epilayer is ErSi 1.7 [0001]∥Si[111] and ErSi 1.7 (10 1 0)∥Si( 11 2)

Heteroepitaxial ErSi1.7 layers with excellent crystallinity (χmin of Er is 1.5%) have been prepared by high‐dose 90 keV Er implantation into a Si(111) substrate using channeled implantation. Such an ErSi1.7/Si system offers a rare opportunity to study comprehensively the structure, orientation, and strain using Rutherford backscattering spectrometry and channeling analysis. We found that the minimum yield and width of the [0001] dip of the Er atoms are quite different from that of the Si atoms in the silicide layer. It is confirmed that the azimuthal orientation of the hexagonal ErSi1.7 layer to the cubic Si substrate is ErSi1.7 [0001] ∥ Si[111] and ErSi1.7 {1120} ∥ Si {110}, and that the epilayer is compressively strained. Besides, by using the angular scan and image scan, we reveal that the dips of the {1010} family are missing for the Si atoms in the epilayer but do exist for the Er atoms in the same epilayer. The reason for this drastic difference is explained by the separate {1010} planes and the different steering potential of the Si and Er atoms in ErSi1.7.

The magnetic viscosity of Sm 2 Fe 17 N x ( x =1.6−3.5) with different particle sizes was measured with a vibrating sample magnetometer at 10–373 K and during a period of t = 6–1000 s. The magnetic viscosity parameter S v was found to vary with the nitrogen concentration, showing a maximum value at x = 3.0. The relationship between log( S v ) and log( H c ) fits the Barbier linear plot fairly well, with a slope of about 0.9. The activation volume V of Sm 2 Fe 17 N x decreases as the nitrogen concentration increases. The value of V can be related to the H c value by H c = V − n ( n = 1.0−1.4).

An unusual Ni distribution with two completely separated buried and surface silicide layers has been observed after Ni ion implantation in Si(111) kept at a temperature of 300°C, with a dose of 1.1 × 10 17 /cm 2 and at a fixed energy of 90 keV. The Ni profile and its substrate temperature dependence, its dose dependence and the influence from the preceding Co implantation were studied by RBS, AES and TEM. A model based on the diffusion of the transition metal, defect annealing during the implantation, and the gettering power of the surface and the end-of-range defects is presented.

X-ray diffraction, transmission electron microscopy and Rutherford backscattering/channeling are used to characterize the structure of an InGaN/GaN multiple quantum well (MQW) grown on an Al/sub 2/O/sub 3/(0001) substrate. Using the combination of these measurements, not only the layered structure of the MQW is revealed clearly but also the In content x (0.16) of the In/sub x/Ga/sub 1-/N component can be determined reliably, which is a prerequisite for further determination of the elastic strain of the MQW. X-ray /spl theta/-2/spl theta/ scans of the (0002) and (101~4) diffractions are used to determine the average lattice parameters and of the MQW, consequently the average parallel elastic strain = -0.25% and the average perpendicular elastic strain = +0.13% of the MQW are deduced. The experimental result of / = -0.52 is in good agreement with the value deduced from the elastic constants.

Hyperkalemia-induced arrhythmias are commonly observed in emergency medicine. Clinically, hyperkalemia is verified through laboratory tests, which takes 20 minutes or more to generate results. To increase the efficiency of treatment, the identification and classification of hyperkalemia directly from electrocardiogram are crucial. In this study, we developed a two-stage artificial neural network (ANN) to classify the disorder of electrolyte from 20 normal and 20 moderate hyperkalemic (5.4 - 7.4 mmole/L) individuals. The first stage of ANN, consisting of two multi-layer back-propagation ANNs, was fed with selected features extracted directly from 12-lead electrocardiograms. The second stage was composed of a two-layer back-propagation ANN receiving input from the outcomes of previous stage. A total of 17 features were selected, among which 12 features including T wave amplitude and duration from V1to V6 leads served as the inputs of the first ANN in the first stage and the other 5 features including P wave amplitude and duration, QRS duration, PR interval, averaged RR interval from lead II served as the inputs of the second ANN in the first stage. By training the two-stage ANN with 30 normal and 30 hyperkalemic cases, the results indicated that the accuracy is 62.5% with sensitivity 12/20. In conclusion, the algorithm developed in this study can predict hyperkalemia more efficiently compared to the prediction by experienced clinicians whose accuracy is 50 % with sensitivity 7/20. It can be expected that the sensitivity and the accuracy will be promoted once the training data increase.

Commercial light emitting devices (LEDs) containing InGaN layers offer unrivaled performance in the violet ({approximately}400 nm), blue ({approximately}450 nm) and green ({approximately}520 nm) spectral regions. Nichia Chemicals Company has also produced amber InGaN LEDs with peak output near 590 nm. Here, they predict, on purely theoretical grounds, a surprisingly high limiting value of 1020 nm (peak) for InGaN intrinsic emission. The authors partly confirm this prediction by spectroscopic measurements of samples with photoluminescence (PL) peaks between 370 nm and 980 nm. In addition, they have measured the indium content of a range of light-emitting layers, using Rutherford Backscattering Spectrometry (RBS), Extended X-Ray Absorption Fine Structure (EXAFS) and Energy Dispersive X-Ray Analysis (EDX). The PL peak energy is found to depend linearly on the indium fraction: violet-emitting layers have an indium content of {approximately}8%, blue layers {approximately}16% and green layers {approximately}25%. A linear extrapolation to the limit set by the Stokes' shift prediction, mentioned earlier, yields a limiting indium concentration of only {approximately}52%. The profound impact of these results on future extensions of nitride technology and current theoretical models of InGaN is briefly discussed.

The Nd-disilicide, which exists only in a tetragonal or an orthorhombic structure, cannot be grown epitaxially on a Si(111) substrate. However, by adding Y and using channeled ion beam synthesis, hexagonal Nd0.32Y0.68Si1.7 epilayers with lattice constant of aepi = 0.3915 nm and cepi = 0.4152 nm and with good crystalline quality (χmin of Nd and Y is 3.5% and 4.3 % respectively) are formed in a Si(111) substrate. This shows that the addition of Y to the Nd-Si system forces the latter into a hexagonal structure. The epilayer is stable up to 950 °C; annealing at 1000 °C results in partial transformation into other phases. The formation, the structure and the thermal stability of this ternary silicide have been studied using Rutherford backscattering/channeling, x-ray diffraction and transmission electron microscopy.

Thin gadolinium silicide layers have been formed by channeled ion beam synthesis. Continuous and heteroepitaxial GdSil.7 layers with a hexagonal structure and a χmin value of 10% are prepared by Gd ion implantation at 90 keV to a dose of 1.3x1017/cm2 at 450°C in Si(111) using channeled implantation. The hexagonal phase of GdSi1.7 is stable up to a temperature of 850°C. Both the crystalline quality and the phase stability are much better than the results obtained by conventional techniques. Annealing at > 900°C suddenly changes the χmin value of the silicide layer from 10% to 100%. X-ray diffraction shows that the phase has changed to orthorhombic. RBS/channeling, x-ray diffraction and transmission electron microscopy are used in this study.

The results are discussed of the characterization by means of TEM, RBS and XRD of ErSi2-x layers prepared by ion beam synthesis on (111) silicon. It will be shown that high quality (buried) layers can be prepared by channelled implantation of the erbium, whereas unchannelled implantation leads to discontinuous polycrystalline surface layers. The epitaxial growth and vacancy ordering in the silicide are discussed.