Edge Of Stack Research Articles

3-D Self-aligned Stacked Ge Nanowires Complementary FET Featuring Single Gate S imple P rocess

3-D Self-aligned Stacked Ge Nanowires Complementary FET Featuring Single Gate S imple P rocess

3-D Self-Aligned Stacked Ge Nanowire pGAAFET on Si nFinFET of Single Gate CFET

3-D Self-Aligned Stacked Ge Nanowire pGAAFET on Si nFinFET of Single Gate CFET

Electronic “Bridge” Construction via Ag Intercalation to Diminish Catalytic Anisotropy for 2D Tin Diselenide Cathode Catalyst in Lithium–Oxygen Batteries

AbstractAs cathode catalysts for lithium–oxygen batteries (LOBs), 2D materials are attracting significant attention due to their layered structures, tunable surface chemistry, and unique electronic states. However, catalytic anisotropy, particularly the poor catalytic capability of the van der Waals forces contained in stack edge planes, has suppressed the enhancement of LOB performance as 2D cathode catalysts. Here, an ion‐intercalation strategy is proposed to diminish the catalytic anisotropy of 2D materials. Ag ions are successfully intercalated into SnSe2 layered structure and regulate the electronic states between stack edge planes, leading to an improvement in the catalytic capability of 2D SnSe2. Notably, the catalytic capability of the 2D surface (001) plane of SnSe2 is also significantly enhanced after Ag intercalation, which can efficiently accelerate charge transfer and suppress the passivation on the 2D surface plane during the oxygen reduction/evolution reaction process. As a consequence, the Ag‐intercalated SnSe2 cathode exhibits superior specific capacity of 16871 mAh g−1 and an ultrastable cycle life over 2300 h at a current density of 100 mA g−1 and 144 cycles at current density of 1000 mA g−1. This work provides insights into the modulation of the catalytic capabilities of 2D materials, which have significant potential for this application in LOBs.

2D SnSe Cathode Catalyst Featuring an Efficient Facet‐Dependent Selective Li2O2 Growth/Decomposition for Li–Oxygen Batteries

Abstract2D materials are attracting much attention in the field of cathode catalysts for lithium–oxygen batteries (LOBs) due to their layered structure, unique electronic properties, and high stability. However, different stacking layer structures trigger different catalytic capabilities in LOBs. In this work, tin selenide nanosheets with a black phosphorus‐like 2D structure are synthesized and used as the cathode catalyst for LOBs. SnSe nanosheets with exposed stack (200) facets and stack edge facets exhibit superior specific capacity over 20 783 mAh g−1 and ultralong cycle stability over 380 cycles at 500 mA g−1 in LOBs. This demonstrates that the growth of discharge products is mainly concentrated on the 2D surface (200) facets, rather than the stack edge facets. Experimental and theoretical studies reveal that the confined adsorption of Li2O2 on the stack edge facets of SnSe, due to the 2D layer structure and the unique electron distribution, restricts the growth of discharge products. The 2D surface facets of SnSe benefit for the formation and stabilization of LiO2 intermediates, leading to the efficient formation/decomposition of discharge products. The findings provide in‐depth insight into the elusive electrocatalytic mechanism for 2D layer‐structures materials in LOBs.

Characteristics and main factors of foam flow in broken rock mass in coal mine goaf.

To protect the environment and reduce the occurrence of coal mine fire, foam injection in goafs is an effective measure for preventing and extinguishing mine fires. The flow characteristics of foams injected into goafs have a significant impact on the prevention and extinguishment of such fires. To study the flow characteristics of foam injected into a goaf, we first independently constructed a set of experimental platforms for the visualization of goafs. Next, we performed physical experiments on foam injection using similarity theory. Flow characteristics were simulated under different foam concentrations, flow rates, and goaf porosities. The exponential function was found to provide a good fit to the trajectory of the foam's stacking edge in the goaf. According to the foam injection volume, the trend of the fitting equation parameter a could be divided into two stages. The first stage was the rapidly decreasing stage, and the second stage was the stable stage. It was inferred that the stacking height and diffusion radius of the foam under different conditions were related to the speed of liquid film drainage. The results of this study can provide a valuable reference for the use of fire prevention and extinguishment technology in the goaf.

Exploring an edge convolution and normalization based approach for link prediction in complex networks

Link prediction in complex networks is to discover hidden or to-be-generated links between network nodes. Most of the mainstream graph neural network (GNN) based link prediction methods mainly focus on the representation learning of nodes, and are prone to over-smoothing problem. This paper dedicates to the representation learning of links, and designs an edge convolution operation so as to realize the link representation learning. Besides, we propose an normalization strategy for the learned link representation, for the purpose of alleviating the over-smoothing problem of edge convolution based link prediction model, when constructing the link prediction graph neural network EdgeConvNorm with stacking edge convolution manipulations. Lastly, we employ a binary classifier sigmod on the Hadamard product of two nodes representation parsed from the final learned link representation. The EdgeConvNorm can also be employed as a baseline, and extensive experiments on real-world benchmark complex networks validate that EdgeConvNorm not only alleviates the over-smoothing problem, but also has advantages over representative baselines.

Numerical analysis of the flow pathlines in thermo-acoustic couples

Abstract Thermo-acoustic systems use a high amplitude sound-wave for refrigeration or electricity generation without the drawbacks of expensive construction, adverse environmental impact or high maintenance cost. The effective conversion of energy occurs within the “stack” considered as the heart of the system. The time-averaged rate of heat transfer across the edges of the stack is a good indicator of an effective performance. Hence, studying the effect of the geometry of the stack edges together with their locations is useful. Furthermore, current manufacturing practices make it possible to develop diverse stack edges, resulting in an improved efficiency of the heat transfer. For effective modelling of the heat transfer rate, a second-order, double-precision discretization of state variables and a laminar viscous model was used. A numerical model was developed using the commercial code FLUENT. The evolution of the flow vortices at different drive ratio was analyzed. Two edges shapes were considered namely rectangular and rounded edges. Using numerical analysis, this study has pointed out that stack edge profiles has a significant effect on the overall performance of thermo-acoustic systems. Rounding the stack edge profile appears to be beneficial for the system performance. This study points out the link between the non-linearity observed in thermo-acoustic systems, the flow streaming and the mean vorticity at the stack edges.

The Influence of Stack Position and Acoustic Frequency on the Performance of Thermoacoustic Refrigerator with the Standing Wave

Abstract Thermoacoustic refrigerator uses acoustic power to transport heat from a low-temperature source to a high-temperature source. The increasing interest in thermoacoustic technology is caused due to its simplicity, reliability as well as application of environmentally friendly working fluids. A typical thermoacoustic refrigerator consists of a resonator, a stack of parallel plates, two heat exchangers and a source of acoustic wave. The article presents the influence of the stack position in the resonance tube and the acoustic frequency on the performance of thermoacoustic refrigerator with a standing wave driven by a loudspeaker, which is measured in terms of the temperature difference between the stack edges. The results from experiments, conducted for the stack with the plate spacing 0.3 mm and the length 50 mm, acoustic frequencies varying between 100 and 400 Hz and air as a working fluid are consistent with the theory presented in this paper. The experiments confirmed that the temperature difference for the stack with determined plate spacing depends on the acoustic frequency and the stack position. The maximum values were achieved for resonance frequencies and the stack position between the pressure and velocity node.

Formation and Strain Analysis of Stacked Ge Quantum Dots With Strain‐Compensating Si1−xCx Spacer

To stack Ge quantum dots (QDs) in a multilayer structure without undesirable enlargement of the QDs, the effects of both Si1−xCx spacer on a strain compensation of the embedded QDs and a sub‐monolayer (ML) carbon (C) mediation on a formation of the Volmer‐Weber (VW)‐mode Ge QDs on the Si1−xCx spacer were investigated. In a Si1−xCx/Ge/Si(100) structure, lattice rexation of the embedded QDs was kept about 80% at x = 0.015. This maintaining the state of high relaxation attributed to a tensile strain from the Si1−xCx layer grown on a surface of a Si substrate around the QDs. In addition, by utilizing an analysis of Kelvin probe force microscopy, it was revealed that the sub‐ML C mediation of 0.25 ML and over is effective to form the VW‐mode Ge QDs on the Si1−xCx spacer. This is because the promotion of subdivision effect for the formation of the QDs via C mediation was also effective on the Si1−xCx surface. At C = 0.25 and 0.5 ML, diameter and density of second QDs were about 22 nm and 1.5 × 1011 cm−2, respectively. These results pave the way to stack the VW‐mode Ge QDs in the multilayer structure without enlargement of the QDs.

412 スタック形状の差異による直管型熱音響冷凍機の冷却特性に関する研究(エネルギー有効利用・需給マネジメント)

The thermoacoustic system has attracted attention as an effective utilization of low-temperature waste heat. The purpose of this study is to enhance the performance of the thermoacoustic cooling system by examining the cooling characteristics of the thermoacoustic refrigerator. In this paper, a straight-tube type thermoacoustic refrigerator is constructed and evaluated based on the temperature difference between the stack's edges and work intensity of sound by focusing on the geometric influence of the stack, such as the density and length. Air is employed as a working gas, and the sound source is supplied by a woofer speaker with a sound generator and power amplifier. As a result, the consumed energy in the stack increases as the length and density of the stack become longer and higher, and there is an optimum stack length to have a higher temperature difference between the stack's edges.

Silhouette-Edge-Based Descriptor for Human Action Representation and Recognition

Extraction and representation of postures and/or gestures from human activities in videos have been a focus of research in this area of action recognition. With various applications cropping up from different fields, this paper seeks to improve the performance of these action recognition machines by proposing a shape-based silhouette-edge descriptor for the human body. Information entropy, a method to measure the randomness of a sequence of symbols, is used to aid the selection of vital key postures from video frames. Morphological operations are applied to extract and stack edges to uniquely represent different actions shape-wise. To classify an action from a new input video, a Hausdorff distance measure is applied between the gallery representations and the query images formed from the proposed procedure. The method is tested on known public databases for its validation. An effective method of human action annotation and description has been effectively achieved.

CMOS-Compatible Precise Placement of Ge Quantum Dots for Nanoelectronic, Nanophotonic, and Energy Conversion Devices

We have developed a self-assembled CMOS compatible scheme for the generation of Ge QDs through thermal oxidation of Si1-xGex patterned structures as well as demonstrated precise QD placement by guiding Ge nucleus migration along the oxidation path and thus arranging them onto targeted locations where the ultimate oxidation occurs. Thereby a single QD self-aligned with electrodes through nanoscale tunnel barriers of SiO2/Si3N4 is realized for an effective management of single electron tunneling. On the other hand, using the fidelity of lithographic patterning and selective oxidation of SiGe pillars well-organized 3D stacked Ge QDs are precisely placed vertically and laterally, and the stacking number is managed by conditions of etching and layer deposition. Stacked QDs luminescence tunable over the visible and possess low thermal conductivity, showing promise for nanophotonic and energy conversion devices.

Optical and structural studies of highly uniform Ge quantum dots on Si (001) substrate grown by solid-source molecular beam epitaxy

We have studied Ge self-assembled quantum dots (QDs) grown by molecular beam epitaxy on Si (001) substrates. We investigated the effect of a pulse growth technique, which involves the combination of a high deposition rate of 2.8Å/s and a 5-s growth interruption (GI) time, on the properties of 20-layer stacked Ge QDs. We found that both the size and size dispersion of the QDs grown using the pulse growth technique were successfully maintained without generating any dislocations even after 20 layers of stacking. Further, a high sheet density of 6.9×1010cm−2 and better size dispersion of 12.4% can be achieved. In photoluminescence (PL) measurements, PL emission at 0.833eV with line width of 71.2meV was clearly observed at 12K for 20-layer stacked Ge QDs grown using the pulse growth technique.

Underlying strain-induced growth of the self-assembled Ge quantum-dots prepared by ion beam sputtering deposition

The quantum-dot samples with single Ge layer and twofold stacked Ge layers are prepared by ion beam sputtering deposition. The different sizes and morphologies of quantum-dots are characterized using atomic force microscope technique. The effects of strain from the capped Ge quantum-dots on the upper Ge wetting layer and the nucleation are also investigated by the buried strain model. The results show that the non-uniform strain in the Si spacing layer which caps the buried quantum-dot layer, leads to the decrease of Ge critical thickness in the upper layer, which increases the upper dot size. The strain intensity increases with the decrease of Si spacer thickness, which results in the changes of dot shape and size in the upper layer. Furthermore, the strain also modulates the distribution of upper quantum-dot layer.

Atomic Simulation of Effect of Stacking Fault and Dislocation on Fracture Behavior in Fe Crystal

The defects in crystalline materials significantly affect the fracture behaviors. In this paper molecular dynamics (MD) model using a potential of embedded atom method (EAM) has been developed to investigate the effect of the major crystalline defects, stacking fault and edge dislocation, on the crack propagation in Fe crystal. Six cases with different locations of stacking fault and edge dislocation have been studied. The strain distribution in lattice aggregate was heterogeneous. The dislocations were observed slipping along directions [100] and [-100] on the plane (100). Simulation results showed that the location of the stacking fault and edge dislocation significantly influenced the crack propagation speed.

Numerical comparison of thermoacoustic couples with modified stack plate edges

It has been demonstrated that the bulk of time-averaged heat transfer between the oscillating fluid and a thermoacoustic couple is concentrated towards the edges of the stack plate. Previous numerical studies which have considered thermoacoustic couples of finite thickness have used a rectangular form for the plate edge. In practice however, current manufacturing practices allow for a variety of stack edges which may improve the efficiency of heat transfer and/or reduce entropic losses. In this numerical study, the performance of a thermoacoustic couple is investigated at selected drive ratios and using a variety of stack plate edge profiles. Results indicate that stack profiles with enlarged and blunter shapes improve the rate of heat transfer at low drive ratios but retard the rate of heat transfer at higher drive ratios due to increased residence time of the fluid in contact with the stack plate. The improvement in COP through minimisation of acoustic streaming on the inside face of the stack, and increased effective cooling power by greater retention of stack thickness at the plate extremities, leads to recommendation of the Rounded edge shape profile for thermoacoustic stack plates in practical devices.

Numerical study of the performance of thermally isolated thermoacoustic-stacks in the linear regime

A simplified calculus model to investigate on the transverse heat transport near the edges of a thermally isolated thermoacoustic stack in the low acoustic Mach number regime is presented. The proposed methodology relies on the well known results of the classical linear thermoacoustic theory which are implemented into an energy balance calculus-scheme through a finite difference technique. Details of the time-averaged temperature and heat flux density distributions along a pore cross-section of the stack are given. It is shown that a net heat exchange between the fluid and the solid walls takes place only near the edges of the stack plates, at distances from the ends not exceeding the peak-to-peak particle displacement amplitude. The structure of the mean temperature field within a stack plate is also investigated; this last results not uniform near its terminations giving rise to a smaller temperature difference between the plate extremities than that predicted by the standard linear theory. This result, when compared with experimental measurements available in literature, suggests that thermal effects localized at the stack edges may play an important role as sources of the deviations found between linear theory predictions and experiments at low and moderate Mach numbers.

Grazing incidence small angle x-ray scattering study for determining structure and composition of multi -stack Ge nanowires on Si(113)

Grazing incidence small angle x-ray scattering study for determining structure and composition of multi -stack Ge nanowires on Si(113)

Effects of gate edge profile on off-state leakage suppresion in metal gate/high-k dielectric n-type metal-oxide-semiconductor field effect transistors

The impact of process integration on device characteristics of metal gate/high-k device was investigated systematically. It was found that the profile of gate stack edge and following processes should be optimized to achieve low gate-induced drain leakage, gate leakage, and high drive current. For low standby power applications, an offset of high-k dielectric layer was more desirable. With an optimized gate edge profile, the authors achieved 100 times lower off-state current compared to previous reported results. However, the saturation current degradation was minimal.

Computation of the time-averaged temperature fields and energy fluxes in a thermally isolated thermoacoustic stack at low acoustic Mach numbers

A simplified calculus model to investigate on the transverse heat transport near the edges of a thermally isolated thermoacoustic stack in the low acoustic Mach number regime is presented. The proposed methodology relies on the well-known results of the classical linear thermoacoustic theory which are implemented into an energy balance calculus-scheme through a finite difference technique. Details of the time-averaged temperature and heat flux density distributions along a pore cross-section of the stack are given. It is shown that a net heat exchange between the fluid and the solid walls takes place only near the edges of the stack plates, at distances from the ends not exceeding the peak-to-peak particle displacement amplitude. The structure of the mean temperature field within a stack plate is also investigated; this last results not uniform near its terminations giving rise to a smaller temperature difference between the plate extremities than that predicted by the standard linear theory. This result, when compared with experimental measurements available in literature, suggests that thermal effects localized at the stack edges may play an important role as sources of the deviations found between linear theory predictions and experiments at low and moderate Mach numbers.