A Consistent Systems Mechanics Model of the 3D Architecture and Dynamics of Genomes

Identifying the Root Cause of Source-Drain Leakage Caused Soft Fail in Advanced Bulk FinFET Devices

10.31399/asm.cp.istfa2018p0383 ◽

2018 ◽

Author(s):

Liangshan Chen ◽

Yuting Wei ◽

Tanya Schaeffer ◽

Chongkhiam Oh

Keyword(s):

Careful Analysis ◽

Physical Analysis ◽

Device Structure ◽

Tem Analysis ◽

Root Cause ◽

3D Architecture ◽

Cause Of Failure ◽

Electrical Analysis ◽

Electrical Data

Abstract The paper reports the investigation on the root cause of source-drain leakage in bulk FinFET devices. While the failing device was readily isolated by nanoprobing technique and the electrical analysis pinpointed the potential defect location inside the Fin channel, the identification of physical root cause went through extreme challenges imposed by the tiny-sized device and the unique FinFET 3D architecture. The initial TEM analysis was misled by the projection of a species in the lamella surface and thus could not explain the electrical data. Careful analysis on the device structure was able to identify the origin of the species and led to the discovery of the actual root cause. This paper will provide the analysis details leading to the findings, and highlight the role of electrical understanding in not only providing guidance for physical analysis but also revealing the true root cause of failure in FinFET devices.

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Parametric Surface Modelling for Tea Leaf Point Cloud Based on Non-Uniform Rational Basis Spline Technique

Sensors ◽

10.3390/s21041304 ◽

2021 ◽

Vol 21 (4) ◽

pp. 1304

Author(s):

Wenchao Wu ◽

Yongguang Hu ◽

Yongzong Lu

Keyword(s):

Point Cloud ◽

Principal Component ◽

Point Clouds ◽

Parametric Surface ◽

B Spline ◽

Surface Modelling ◽

Modelling Method ◽

3D Architecture ◽

Tea Leaf ◽

Fitting Error

Plant leaf 3D architecture changes during growth and shows sensitive response to environmental stresses. In recent years, acquisition and segmentation methods of leaf point cloud developed rapidly, but 3D modelling leaf point clouds has not gained much attention. In this study, a parametric surface modelling method was proposed for accurately fitting tea leaf point cloud. Firstly, principal component analysis was utilized to adjust posture and position of the point cloud. Then, the point cloud was sliced into multiple sections, and some sections were selected to generate a point set to be fitted (PSF). Finally, the PSF was fitted into non-uniform rational B-spline (NURBS) surface. Two methods were developed to generate the ordered PSF and the unordered PSF, respectively. The PSF was firstly fitted as B-spline surface and then was transformed to NURBS form by minimizing fitting error, which was solved by particle swarm optimization (PSO). The fitting error was specified as weighted sum of the root-mean-square error (RMSE) and the maximum value (MV) of Euclidean distances between fitted surface and a subset of the point cloud. The results showed that the proposed modelling method could be used even if the point cloud is largely simplified (RMSE < 1 mm, MV < 2 mm, without performing PSO). Future studies will model wider range of leaves as well as incomplete point cloud.

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Stress wave propagation in different number of fissured rock mass based on nonlinear analysis

International Journal of Nonlinear Sciences and Numerical Simulation ◽

10.1515/ijnsns-2019-0301 ◽

2020 ◽

Vol 0 (0) ◽

Author(s):

Xiaoming Lou ◽

Mingwu Sun ◽

Jin Yu

Keyword(s):

Numerical Simulation ◽

Rock Mass ◽

Confining Pressure ◽

Displacement Discontinuity ◽

Stress Wave Propagation ◽

Theoretical Derivation ◽

Mechanics Model ◽

Fissured Rock ◽

Deep Rock ◽

Theoretical Accuracy

AbstractThe fissures are ubiquitous in deep rock masses, and they are prone to instability and failure under dynamic loads. In order to study the propagation attenuation of dynamic stress waves in rock mass with different number of fractures under confining pressure, nonlinear theoretical analysis, indoor model test and numerical simulation are used respectively. The theoretical derivation is based on displacement discontinuity method and nonlinear fissure mechanics model named BB model. Using ABAQUS software to establish a numerical model to verify theoretical accuracy, and indoor model tests were carried out too. The research shows that the stress attenuation coefficient decreases with the increase of the number of fissures. The numerical simulation results and experimental results are basically consistent with the theoretical values, which verifies the rationality of the propagation equation.

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Modelling the asymmetric tension–compression properties of additively manufactured alloys using continuum damage mechanics

Proceedings of the Institution of Mechanical Engineers Part L Journal of Materials Design and Applications ◽

10.1177/14644207211013434 ◽

2021 ◽

pp. 146442072110134

Author(s):

A Nayebi ◽

H Rokhgireh ◽

M Araghi ◽

M Mohammadi

Keyword(s):

Damage Mechanics ◽

Continuum Damage Mechanics ◽

Element Model ◽

Continuum Damage ◽

Compression Tests ◽

Compression Properties ◽

Mechanics Model ◽

Stress Components ◽

Tension And Compression ◽

Closure Effect

Additively manufactured parts often comprise internal porosities due to the manufacturing process, which needs to be considered in modelling their mechanical behaviour. It was experimentally shown that additively manufactured parts’ tensile and compressive mechanical properties are different for various metallic alloys. In this study, isotropic continuum damage mechanics is used to model additively manufactured alloys’ tension and compression behaviours. Compressive stress components can shrink discontinuities present in additively manufactured alloys. Therefore, the crack closure effect was employed to describe different behaviours during uniaxial tension and compression tests. A finite element model embedded in an ABAQUS’s UMAT format was developed to account for the isotropic continuum damage mechanics model. The numerical results of tension and compression tests were compared with experimental observations for additively manufactured maraging steel, AlSi10Mg and Ti-6Al-4V. Stress–strain curves in tension and compression of these alloys were obtained using the continuum damage mechanics model and compared well with the experimental results.

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A novel model of Z-pin insertion in prepreg based on fracture mechanics

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211014442 ◽

2021 ◽

pp. 095440542110144

Author(s):

Guobiao Ji ◽

Liang Cheng ◽

Shaohua Fei ◽

Jiangxiong Li ◽

Yinglin Ke

Keyword(s):

Fracture Toughness ◽

Fracture Mechanics ◽

Analytical Model ◽

Model Parameters ◽

Force Model ◽

Fe Model ◽

Cohesive Elements ◽

Fe Method ◽

Insertion Force ◽

Mechanics Model

Through-thickness reinforcement is a promising solution to the problem of delamination susceptibility in laminated composites. Modeling Z-pin–prepreg interaction is essential for accurate robotics-assisted Z-pin insertion. In this paper, a novel Z-pin insertion force model combining the classical cohesive finite element (FE) method with a dynamic analytical fracture mechanics model is proposed. The velocity-dependent cohesive elements, in which the fracture toughness is provided by the analytical model, are implemented in Z-pin insertion FE model to predict the crack initiation and propagation. Then Z-pin insertion experiments are performed on prepreg sample with metallic Z-pins at different velocities to identify the analytical model parameters and validate the simulation predictions offered by the model. Dynamics of Z-pin interaction with inhomogeneous prepreg is described and the effects of insertion velocity on prepreg contact force are studied. Results show that the force model agrees well with experiments and the fracture toughness rises with the increasing Z-pin insertion velocity.

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Expanding 3D Nanoprinting Performance by Blurring the Electron Beam

Micromachines ◽

10.3390/mi12020115 ◽

2021 ◽

Vol 12 (2) ◽

pp. 115

Author(s):

Lukas Seewald ◽

Robert Winkler ◽

Gerald Kothleitner ◽

Harald Plank

Keyword(s):

Electron Beam ◽

Direct Write ◽

Design Flexibility ◽

Individual Branch ◽

Inclination Angles ◽

3D Architecture ◽

20 Nm ◽

Surface Morphologies ◽

Nm Range ◽

Mechanical Rigidity

Additive, direct-write manufacturing via a focused electron beam has evolved into a reliable 3D nanoprinting technology in recent years. Aside from low demands on substrate materials and surface morphologies, this technology allows the fabrication of freestanding, 3D architectures with feature sizes down to the sub-20 nm range. While indispensably needed for some concepts (e.g., 3D nano-plasmonics), the final applications can also be limited due to low mechanical rigidity, and thermal- or electric conductivities. To optimize these properties, without changing the overall 3D architecture, a controlled method for tuning individual branch diameters is desirable. Following this motivation, here, we introduce on-purpose beam blurring for controlled upward scaling and study the behavior at different inclination angles. The study reveals a massive boost in growth efficiencies up to a factor of five and the strong delay of unwanted proximal growth. In doing so, this work expands the design flexibility of this technology.

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