Wire Model Research Articles

Modeling of electroplated diamond wire and its application towards precision slicing of semiconductors

Electroplated diamond multi-wire sawing is becoming the mainstream technique for semiconductor slicing, because of its desirable traits such as thin slice thickness, low kerf loss, and high surface/subsurface quality. Precisely describing the electroplated diamond wire is of significant importance to slicing process analysis. This study presents an electroplated diamond wire model based on statistical measurements of the cutting-edge geometry and scratching direction of abrasives on wire. These measurements are performed on a commercial wire (Diamond Wire-160) after exposing cutting edges from plated nickel layers. Results show that up to 91 % of abrasives have a single cutting edge with the shape of a triangular or quadrangular pyramid. The geometric angles (α1, α2, γ1, γ2) of these pyramids are observed to follow an approximate Gaussian distribution, and the scratching direction follows a uniform distribution. Combined with nanoindentation theory, the developed model is further employed for slicing process analysis, in which slicing forces and bow angles of wire are calculated. Additionally, slicing experiments are conducted on silicon for model verification, and the maximum relative error between predicted and experimental bow angles is 6.25 %. The developed wire model provides an effective tool for slicing process analysis, thereby accelerating the process development for scale-up production of high-precision semiconductor substrates.

Stability of ground state degeneracy to long-range interactions

We show that some gapped quantum many-body systems have a ground state degeneracy that is stable to long-range (e.g. power-law) perturbations, in the sense that any ground state energy splitting induced by such perturbations is exponentially small in the system size. More specifically, we consider an Ising symmetry-breaking Hamiltonian with several exactly degenerate ground states and an energy gap, and we then perturb the system with Ising symmetric long-range interactions. For these models we prove (a) the stability of the gap, and (b) that the residual splitting of the low-energy states below the gap is exponentially small in the system size. Our proof relies on a convergent polymer expansion that is adapted to handle the long-range interactions in our model. We also discuss applications of our result to several models of physical interest, including the Kitaev p-wave wire model perturbed by power-law density–density interactions with an exponent greater than 1.

Analytic solution for the lightning current induced mutually coupled resistive filament wire model

<abstract><p>When a lightning current flows between the lightning entry and exit points of a structure, the lightning current density varies in different parts of the structure depending on the shape of the structure and material variance. The structure can be discretized into parallel wires, called filament wires, running parallel to the current direction. Furthermore, using the filament wire method, we can calculate the current distribution among the wires. For a structure that has a low resistance material such as aluminum, current distribution can be calculated by considering self-inductance of the wire and mutual-inductance between wires but resistance is not considered. However, in modern aircraft, composite materials are used for parts of the structure because of their strength and weight. These composite materials have high resistance compared to metal, and resistance cannot be ignored. Thus, to solve a system of ordinary differential equations for a filament model, inhomogeneous structure, aperture, and resistance of each wire must be considered to obtain the correct current distribution of each part of the structure. However, the numerical solution of the filament wire model does not reveal the region of convergence and the accuracy of the given mathematical model. It also has high time complexity. This paper presents the analytic solution and stability condition for the mutually coupled resistive filament wire model using eigenvalues of given filament wire matrix model. The stability condition is rigorously calculated and the solution is also consistent with the numerical model.</p></abstract>

Квантовая проводимость в одиночных и связанных квантово-размерных частицах узкозонных полупроводников

An organo-modified ordered layered structure with three-dimensional close packing based on colloidal quantum-sized particles (QP) of InSb, PbS, CdSe semiconductors and Langmuir-Blodgett films has been fabricated and studied. According to the current-voltage characteristics (CVC) of single-electron transport in the model of a nanocell with a linear chain QP across the layers, the processes limiting conductivity were established: emission-injection tunneling from a probe into a nanoparticle, motion in a nanoparticle determined by the establishment of an electronic wave process in it, and tunneling through a nanogap between nanoparticles. Quasi-periodic oscillations of the current and resonant peaks of quantum conductivity are observed on the I–V characteristics, which were estimated in the quantum wire model. For an even number of layers (QP, 2, or 4), the I–V characteristics were used to determine the attenuation of size quantization and the decrease in current due to the weak interaction of nanoparticles. With an odd number (3 or 5), the nanochain acts as a single quantum thread with manifestations on the CVC similar to the cases of one QP. In this case, the motion of an electron can be considered as a one-electron charge wave.

Modeling and experimental investigation of monocrystalline silicon wafer cut by diamond wire saw

Diamond wire sawing is one of the key technologies in solar cell manufacturing process and semiconductor chip manufacturing process. The thinned of silicon wafer has become a development trend of semiconductor industry, and the reduction of silicon wafer thickness can improve the material utilization and reduce the manufacturing cost. Therefore, the minimum thickness analytical model of diamond wire saw cutting monocrystalline silicon wafer is proposed in this paper to study the processing mechanism of minimum thickness of monocrystalline silicon wafer. Firstly, based on the Kirchhoff’s thin plate theory, the theoretical equation of the maximum internal stress of single silicon wafer and the sawing thickness of the silicon wafer is derived from the sawing force model. Combined with the Mohr’s strength theory, the analytical model of minimum sawing thickness of monocrystalline silicon wafer is established. Then, the analytical model is verified by the finite element simulation. The average error between the simulation results and the calculation results of the analytical model about the minimum sawing thickness of silicon wafer is 9%. Finally, the monocrystalline silicon sawing verification experiments are conducted under some groups of processing conditions. The experimental results show that the minimum sawing thickness of the silicon wafer decreases with the increasing axial speed of the wire saw, increases with the increase of the feed rate of the wire saw, and decreases first and then increases with workpiece speed becoming large. The average error of the experimental results and the calculation results of the analytical model of the wafer minimum sawing thickness is 7.4%, which verifies corrections of the analytical model.

Evaluation of Flexible Central Buckles on Short Suspenders’ Corrosion Fatigue Degradation on a Suspension Bridge under Traffic Load

Suspenders are the crucial load-bearing components of long-span suspension bridges, and are sensitive to the repetitive vibrations caused by traffic load. The degradation of suspender steel wire is a typical corrosion fatigue process. Although the high-strength steel wire is protected by a coating and protection system, the suspender is still a fragile component that needs to be replaced many times in the service life of the bridge. Flexible central buckles, which may improve the wind resistance of bridges, are used as a vibration control measure in suspension bridges and also have an influence on the corrosion fatigue life of suspenders under traffic load. This study established a corrosion fatigue degradation model of high-strength steel wire based on the Forman crack development model and explored the influence of flexible central buckles on the corrosion fatigue life of suspenders under traffic flow. The fatigue life of short suspenders without buckles and those with different numbers of buckles was analyzed. The results indicate that the bending stress of short suspenders is remarkably greater than that of long suspenders, whereas the corrosion fatigue life of steel wires is lower due to the large bending stress. Bending stress is the crucial factor affecting the corrosion fatigue life of steel wires. Without flexible central buckles, short suspenders may have fatigue lives lower than the design value. The utilization of flexible central buckles can reduce the peak value and equivalent stress of bending stress, and the improved stress state of the short suspender considerably extends the corrosion fatigue life of steel wires under traffic flow. However, when the number of central buckles exceeds two, the increase in number does not improve the service life of steel wire.

Gas to Wire (GTW) Model in Brazil: Challenges and Possibilities

The expansion of natural gas production in Brazil presents some obstacles, the main one being the reduced volume of investments in expanding the transportation, distribution, and commercialization of natural gas produced offshore and onshore in the country. If, on the one hand, the lack of investments in infrastructure for the flow of natural gas produced in the country prevents the expansion of natural gas production in the onshore basins, the transformation of electric power near the reservoirs of natural gas has enabled the viability of projects for exploration and production of natural gas in the Brazilian onshore basins. A review of literature and analysis of secondary data allows the study of technical, legal, and economic factors that enable the implementation of a reservoir to wire projects, from the production of natural gas in the onshore basins of Brazil, aiming at the supply of electric power to the National Electric System. This way, natural gas changes its condition as a complementary energy source, together with the National Electricity System, to exercise the function of a basic energy source for parts of the national system.

An Effective Formability Model of Pearlitic Steel Wires in Multi-stage Drawing Process Based on the Stress-Based Forming Limit Criterion

An Effective Formability Model of Pearlitic Steel Wires in Multi-stage Drawing Process Based on the Stress-Based Forming Limit Criterion

A profile transformation based recursive multi-bead overlapping model for robotic wire and arc additive manufacturing (WAAM)

Robotic Wire and Arc Additive Manufacturing (WAAM) is an ideal process for manufacturing large-scale or large-format parts efficiently and economically, as compared with other AM methods, and therefore finds extensive applications in diverse fields including aerospace, automotive and mould. Accurate prediction of WAAM part dimension is fundamentally dependent on the modeling accuracy of single-bead profile and its subsequent overlapping ones. This paper proposes a new recursive model, based on coordinate transformation, to predict single-layer multi-bead overlapping profile. Firstly, commonly used single-bead profile functions are reviewed, followed by detailed description of conventional and proposed recursive profile model. The properties of developed recursive model are then investigated for understanding the effects of overlapping ratio and single-bead aspect ratio. The influence of function type is also analysed from the surface quality divergence of single-layer multi-bead overlapping profile. Finally, multi-bead overlapping experimental tests are carried out to validate the feasibility of presented recursive profile model. The results show that the modified recursive model is more accurate than the conventional one for its better accountability of valley area. It is also indicated that parabola and arc function are more suitable for the robotic WAAM process. The research outcome is beneficial to improving the forming accuracy of WAAM parts, and also provides a new method for predicting geometry of other additive manufactured products.

A non-destructive model for thermal-hydraulics of wire-wrapped rod bundle and wire-rod contact corner microscopic behavior

Wire-wrapped rod bundle numerical simulation relates to multiscale parameters, such as axial length of the rod bundle (600 mm) and wire-rod contact corner (0.4 mm). The existing studies tend to adopt the embedding approximation wire model, which cannot simulate microscopic behavior at the wire-rod contact corner and bring the uncertainty of numerical models. To simulate the actual situation of the wire-wrapped rod bundle, this paper established a high-precision non-destructive wrapped wire model based on virtual ellipse flow surfaces and fillet connection and then investigated the thermal-hydraulics of the wire-wrapped rod bundle and microscopic behavior at wire-rod contact corner at the working pressure of 25 MPa, inlet temperature of 692.45 K, mass flux of 1000 kg/m2·s, and heat flux of 400 kW/m2. The influence of the distance of wire embedded into the rod bundle on heat transfer and pressure drop was quantitatively analyzed. ω-RSM turbulence model is used due to its higher prediction accuracy in the high enthalpy region (enthalpy >2700 kJ/kg). The result shows that numerical simulation has a good agreement with the experimental data. Compared with embedding approximation models, the high-fidelity non-destructive wrapped wire model shows better heat transfer and greater friction resistance. The wire-wrapped rod bundle increased the heat transfer coefficient by 14% and increased the friction factor by 10% compared with the bare rod bundle. A dead-water area exists at the wire-rod contact corner with the phenomena of low velocity, poor heat transfer and high fluid temperature. This numerical investigation helps to optimize the wire structure design while providing insight into the influence of wire.

Effects of Rigid and Nonrigid Connections between the Miniscrew and Anchorage Tooth on Dynamics, Efficacy, and Adverse Effects of Maxillary Second Molar Protraction: A Finite Element Analysis.

Introduction Direct, rigid indirect, and nonrigid indirect absolute anchorages using temporary anchorage devices (TADs, mini-implants/miniscrews) can provide promising opportunities for challenging, yet common, orthodontic tooth movements such as molar protraction. Rigid rectangular wire and ligature wire are the most common methods of attaching a tooth to a miniscrew in indirect anchorages. We aimed to provide a comparison of the rigidity of the connecting wire in terms of stress on the miniscrew, the anchorage loss, and the risk of root resorption using finite element analysis (FEA). Methods The maxillary right second molar was protracted into the proximal space at a 150 g load (1) using direct absolute anchorage with a tapered miniscrew implanted between the premolar roots and using indirect absolute anchorage with the second premolar reinforced by the miniscrew through (2) a rigid stainless steel (SS) wire or (3) a nonrigid SS ligature wire (4) at different elastic moduli. Stresses and displacements of 4 models' elements were measured. The risk of external root resorption was evaluated. Results Connecting the tooth to the miniscrew using rigid full-size wire (model 2) compared to ligature (model 3) can give better control of the anchorage (using the ligature wire, the anchorage loss is 1.5 times larger than the rectangular wire) and may reduce the risk of root resorption of the anchorage unit. However, the risk of miniscrew failure increases with a rigid connection, although it is still lower than with direct anchorage. The miniscrew stress when using a ligature is approximately 30% of the rigid model using the rectangular wire. The miniscrew stress using the rectangular wire is approximately 82.4% of the miniscrew stress in the direct model. Parametric analysis shows that the higher the elastic modulus of the miniscrew-tooth connecting wire in the indirect anchorage, the less the anchorage loss/palatal rotation of the premolars/and the risk of root resorption of the anchorage teeth and instead the stress on the miniscrew increases. Conclusions Direct anchorage (followed by rigid indirect anchorage but not nonrigid) might be recommended when the premolars should not be moved or premolar root resorption is a concern. Miniscrew loosening risk might be the highest in direct anchorage and lowest in nonrigid indirect anchorage (which might be recommended for poor bone densities).

Electromagnetic Wave Scattering by a Multiple Core Model of Composite Cylindrical Wires at Oblique Incidence

A complex cylindrical structure consisting of a group of parallel stratified circular lossy dielectric cylinders, embedded in a dielectric circular cylindrical region and surrounded by unbounded dielectric space, is considered in this paper. The scattering of electromagnetic (EM) plane waves by the aforementioned configuration was studied; the EM waves impinged obliquely upon the structure and were arbitrarily polarized. The formulation used was based on the boundary-value approach coupled with the generalized separation of variables method. The EM field in each region of space was expanded in cylindrical wave-functions. Furthermore, the translational addition theorem of these functions was applied in order to match the EM field components on any cylindrical interface and enforce the boundary conditions. The end result of the analysis is an infinite set of linear algebraic equations with the wave amplitudes as unknowns. The system is solved by the truncation of series and unknowns and then matrix inversion; thus, we provide a semi-analytical solution for the scattered far-field and, as a consequence, for the scattering cross section of the complex cylindrical structure. The numerical results focus on calculations of the electric- and magnetic-field intensity of the far-field as well as of the total scattering cross section of several geometric configurations that fall within the aforementioned general structure. The effect of the geometrical and electrical characteristics of the structure on the scattered field was investigated. Specifically, the cylinders’ size and spacing, their conductivity and permittivity as well as the incidence direction were modified in order to probe how these variations are imprinted on scattering. Moreover, comparisons with previously published results, as well as convergence tests, were performed; all tests and comparisons proved to be successful.

The Optimization Study for Electromagnetic Radiation With Ultrahigh Voltage Transmission Lines

Several factors affect the electromagnetic environment changes generated underneath high-voltage transmission lines. This article carries out a study on the impact of the electromagnetic environment on high-voltage transmission lines based on different tower structures, voltage levels, conductor layouts, conductor parameters, and other full range of engineering factors. First, the model of wire three-phase phase sequence, ground height, horizontal phase spacing, wire splitting number, split spacing, and model values are built. By continuously adjusting and optimizing the parameters, the electromagnetic environment distribution curve at 1.8 m above the horizontal plane is obtained. Then, according to the characteristic analysis of the distribution law after optimization, the simulation results under some typical factors are compared with the standard limits. Simultaneously, the effect of this optimization is verified by comparison with relevant literature. Finally, some suggestions on the optimization of the pole tower structure, transmission line parameters, and the influence of electromagnetic radiation in transmission line corridors are proposed in high-voltage transmission line projects, which may potentially have constructive contributions and value.

The gap-filling overlapping model for wire and arc additive manufacturing of multi-bead components

The gap-filling overlapping model for wire and arc additive manufacturing of multi-bead components

Stability of the smectic phase in arrays of parallel quantum wires

Using bosonization, we study a microscopic model of parallel quantum wires constructed from two dimensional Dirac fermions in the presence of periodic topological domain walls. The model accounts for the lateral spread of the wavefunctions $\ell$ in the transverse direction to the wires. The gapless modes confined to each domain wall are shown to form Luttinger liquids, which realize a well known smectic non-Fermi liquid fixed point when interwire Coulomb interactions are taken into account. Perturbative studies on phenomenological models have shown that the smectic fixed point is unstable towards a variety of phases such as superconductivity, stripe, smectic and Fermi liquid phases. Here, we show that the considered microscopic model leads to a phase diagram with only smectic metal and Fermi liquid phases. The smectic metal phase is stable in the ideal quantum wire limit $\ell\to0$. For finite $\ell$, we find a critical Coulomb coupling $\alpha_{c}$ separating the strong coupling smectic metal from a weak coupling Fermi liquid phase. We conjecture that the absence of superconductivity should be a generic feature of similar microscopic models. Finally, we discuss the physical realization of this model with moire heterostructures.

Damage and fracture analyses of wire with V‐shaped microcrack on multi‐pass drawing under back tensions

AbstractWire breakage has always attracted much attention in drawing. Mastering the mechanism of drawing fracture can effectively improve the quality of steel wire. In this study, the morphology of the fracture samples is analyzed. There are obvious V‐shaped microcracks in the materials by observing the microstructure. Base on the above results, the wire models with V‐shaped microcrack of different inclinations are established via the finite element method (FEM). Besides, the multi‐pass drawing under different back tension is simulated, and the process from crack propagation caused by damage to fracture is realized. The results show that microcrack has a great influence on the drawing fracture, and inclination is a key factor. With the increase of angle, the propagation rate of crack increases accordingly. Meanwhile, back tension will increase the accumulation of damage. The larger the back tension is, the larger the crack path is, which eventually leads to the formation of pen‐tip shaped fracture.

The Development and Verification of a Simulation Model of Shape-Memory Alloy Wires for Strain Prediction

One of the greatest challenges in the design of shape-memory elements (mostly binary Nickel-Titanium wires) is to ensure that the required travel (stroke) is achieved, as this is subject to variation due to various influencing factors. One way of predicting the stroke is to use a suitable energy model. In the past, for example, a model was developed by Oelschläger with which the stroke can be calculated on the basis of the electrical energy. However, so far no model takes into account the change of the phase transformation temperature. In this study, the model of Oelschläger is extended and verified to consider the degradation behavior over the whole lifetime. For this purpose, fatigue tests of 52 wires (2 different load scenarios) were performed. Based on these tests and the application of statistical methods (distribution models, goodnes-of-fit tests etc.), a target model was developed for each load scenario, which is used to verify the extended energy model. The energy model was applied to wires of both load scenarios to simulate the stroke progression. The verification of the extended simulation model shows that it is possible to simulate the longterm behavior of the stroke for one of the two load scenarios. The second load scenario shows deviations between the target model and the simulation, which is due to problems in the area of measurement equipment, convection, and temperature distribution in the wire. Nevertheless, a decisive modeling approach could be developed, which can be used to consider the long-term behavior of the phase transformation temperature of wires in simulations.

Quantum wires, Chern-Simons theory, and dualities in the quantum Hall system

Over the years, many theoretical frameworks have been developed to understand the remarkable physics of the quantum Hall system. In this work we discuss the interplay among quantum wires, Chern-Simons theory, bosonization, and particle-vortex duality, which enable a unified approach for the Laughlin states of the fractional quantum Hall system. Starting from the so-called quantum wires system, which is a semi-microscopic description in terms of 1+1 dimensional theories, we discuss the emergence of 2+1 dimensional low-energy effective field theories by using different maps connecting the microscopic degrees of freedom with the macroscopic ones. We show the origin of these maps by embedding the bosonized version of the original quantum wires model in a gauge invariant theory and using particle vortex-duality.

Adolescent development of multiscale structural wiring and functional interactions in the human connectome

Adolescence is a time of profound changes in the physical wiring and function of the brain. Here, we analyzed structural and functional brain network development in an accelerated longitudinal cohort spanning 14 to 25 y (n = 199). Core to our work was an advanced invivo model of cortical wiring incorporating MRI features of corticocortical proximity, microstructural similarity, and white matter tractography. Longitudinal analyses assessing age-related changes in cortical wiring identified a continued differentiation of multiple corticocortical structural networks in youth. We then assessed structure-function coupling using resting-state functional MRI measures in the same participants both via cross-sectional analysis at baseline and by studying longitudinal change between baseline and follow-up scans. At baseline, regions with more similar structural wiring were more likely to be functionally coupled. Moreover, correlating longitudinal structural wiring changes with longitudinal functional connectivity reconfigurations, we found that increased structural differentiation, particularly between sensory/unimodal and default mode networks, was reflected by reduced functional interactions. These findings provide insights into adolescent development of human brain structure and function, illustrating how structural wiring interacts with the maturation of macroscale functional hierarchies.

Estimation of heat transfer model parameters by using recursive least square (RLS) method for a shape memory alloy wire

The thermal model of shape memory alloy (SMA) wires is improved by identifying the convectional heat transfer model (htm) parameters. Recursive Least Square (RLS) Method is used to estimate heat transfer coefficient, specific heat and latent heat coefficient. The parameters are estimated altogether with the surface area, volume and density of the wire. Also, after measuring the resistance by using multimeter, the value of each parameter was separately determined. Heat transfer coefficient is ambient dependent and dominant in the heat transfer model. The estimation of heat transfer coefficient is important and this is shown in this study. The proposed method builds an improved heat transfer model for SMA wire by using a single set of experimental data. Performance of the estimation with RLS is validated by using the measured data. It is shown that heat convection coefficient can be estimated with high accuracy. Thus, it is revealed that addition of the latent heat term during phase transformation into the model resulted in a more accurate model. The accuracy of the model can be enhanced by 28% by the addition of latent heat term.