nils-herrmann/clean_scirepeval huggingface dataset:
Time-domain Green's functions for waves on simplicial complexes

Maxwell's laws of classical electrodynamics have exact counterparts on a purely discrete space, reformulated as discrete Stokes' Theorems on simplicial complexes. We here address the formulation of discrete Green's Theorems and discrete Green's functions in discrete-time on sim-plicial complexes in 3-space as the fully discretised versions of continuum wave equations that preserve Stokes' Theorems in all sub-dimensions of the sim-plicial complexes. These Green's functions have the same applications in discrete wave systems as their continuum counterparts, but are pre-conditioned to live wholly on the discrete space. 3-complexes in space with discrete time-stepping are the natural setting for generalisations of the FDTD algorithm from Yee-cells to general unstructured meshes.
Stable self-consistent Green's function diakoptics without spurious recurrences

The discrete space-time-domain wave interaction between distant computational domains can efficiently be described via Green's function diakoptics. For a toy problem with a computational domain consisting of two non-adjacent points, the inverse of the stability function facilitates the derivation of a stable unlimited lookback scheme. This approach permits the use of inter-domain continuous Green's functions, which eliminates the problem of mesh dispersion, but sacrifices self-consistency. Discrete Green's functions should be used if self-consistency is preferred. For a square lattice, inter-domain mesh dispersion can be suppressed by doubling the number of points per wavelength, for every factor of ten distance increase.
Discrete Green's functions and functional determinants

A theorem is shown in which the elements of the inverse of a symmetric matrix F are constructed by Jacobi's formula using the derivative of the determinant detF with respect to its elements, and the determinant is defined by the partition function of a statistical field theory with interaction matrix F, generally Z = (detF)−1/2. When the matrix F is the discrete Laplacian, the theorem is the essential connection between the discrete Green's function and two-point correlations of the lattice gas.
Modeling second-order nonlinear effects in optical waveguides using a parallel-processing beam propagation method

In this work, we present a simple efficient numerical solution for the three-dimensional coupled wave equations containing a second-order nonlinearity, using an explicit finite difference beam propagation method (EFD BPM). The linear EFD-BPM is known to be very efficient and to gain large speed up when implemented on parallel computers. The new nonlinear version of the EFD-BPM has the same features of the linear counterpart in using two separate computational windows, one for the fundamental field and the other for the second-harmonic field. We demonstrate the implementation and discuss the application of this method to a nonlinear rib waveguide using the quasi-phase-matching technique.
Spurious modes in the DuFort-Frankel finite-difference beam propagation method

In this letter, we analyze the DuFort-Frankel beam propagation method (BPM) which is a modification to the known explicit finite-difference beam propagation method (EFD-BPM) and found that there are some precautions that must he taken before using the method. The accuracy and the efficiency of this method has been shown and compared with the most popular FD-BPMs.
The sum-over-paths representation of discrete Green's functions

Classes of cohomology operators based on functions of the discrete Laplacian are constructible in a sum-over-paths formalism. The Laplacian L is an adjacency operator constructed from incidence matrices of the cell complex representing a discrete decomposition of space; a discrete field φ is defined as a function whose domain is a union of discrete elements of the cell complex, which in general may be vertices, edges, faces, or volumes. The discrete-time Green's function corresponding to a discrete Laplacian is constructed. The problem of identification of a localised wavefront in the discrete Green's function on vertices of a 3-dimensional hypercube lattice is examined.
Layered coding using bitstream decomposition with drift correction

It is well known that layered video coding is useful both for service interworking and as an aid to error resilience. A major drawback of layered coding is that it invariably results in a reduction in overall coding efficiency for the high quality service. An attractive approach would be one in which the high quality service is coded, and then the resulting bitstream is decomposed in such a way that the lower resolution services can be reconstructed using only a subset of the total generated data. This would mean that there would be no impact on the coding efficiency of the highest quality service. In this paper we demonstrate that the quality of the lower layer when this approach is used is fundamentally limited by drift. It is shown that even a coarsely quantized, low rate correction signal provides a major benefit to the quality of this lower layer service while still not impacting significantly on the coding efficiency of the high quality service. Of course, some overhead is introduced in the coding of the lower quality service but the total overhead is still significantly better than simulcast.
A 7nm FinFET technology featuring EUV patterning and dual strained high mobility channels

We present a 7nm technology with the tightest contacted poly pitch (CPP) of 44/48nm and metallization pitch of 36nm ever reported in FinFET technology. To overcome optical lithography limits, Extreme Ultraviolet Lithography (EUV) has been introduced for multiple critical levels for the first time. Dual strained channels have been also implemented to enhance mobility for high performance applications.
On-wafer W-band determination of the driving point impedance of a double slot antenna

Part of the ESTEC funded Integrated Antenna Development project includes the development of an optimised 500 GHz planar antenna on a dielectric lens. One aspect of this study involves the development of an accurate model for the antenna impedance at the point where a bolometric detector is inserted in the receiver. To verify the modelling, an on-wafer measurement strategy to determine the driving point impedance of a 100 GHz scale model of the antenna structure was developed. This paper describes the W-band on-wafer measurement technique and compares the experimentally and theoretically derived feed point impedances of the antenna structures.
Preparing to Witness a Multimegawatt Motor and Adjustable Speed Drive Acceptance Test–The Basics

Adjustable speed drive (ASD) and motors, if selected as a prime mover for compressors, pumps, extruders, etc., can provide various electromechanical benefits to its operators and stakeholders. Their benefits and application considerations have been well documented in past papers and tutorials. However, a successful installation of a multimegawatt motor and ASD system requires detailed application, engineering, manufacturing, testing, and installation considerations. Many times testing is requested by the operator and/or consultant, but navigating the types of tests available, test procedures, plans, and how they comply with appropriate standards is often not fully understood. This can lead to surprises, shipment delays, price adders, and ultimately the equipment itself not being in compliance with the stated project objectives. This paper attempts to address the factory acceptance testing phase of a medium voltage motor and ASD system whether procured separately or as a package. Issues such as type of test selection, specifications, standards, preparation, acceptance criteria, and finally string testing will be covered. This paper serves as a guideline of how one can select, prepare, witness, and sign off on a medium voltage motor and ASD test.
Rigorous Evanescent Wave Theory for Guided Modes in Graded Index Optical Fibers

The evanescent wave theory of modal propagation in graded index optical fiber developed recently by Choudhary and Felsen is based on certain postulates, which are examined here. It is shown that an analytical condition on the asymptotic expansion coefficents for the modal amplitudes on the fiber axis, as imposed by these authors, should be replaced by the single-valuedness of these coefficients in a strip of the complex coordinate plane. The analyticity condition is of questionable validity because of the nonunifomity of the asymptotic expansion on the axis. The previous results of Choudhary and Felsen are found to be unaffected by this change but the method is now made rigorous and need not be justified, as before, by comparison with asymptotic expansions of exact solutions for special profiles. Also developed here is a uniform asymptotic approximation that is valid near the fiber axis and connects with the leading term of the nonuniform evanescent wave theory formulation. Within this rigorous framework, the evanescent wave theory continues to provide a very useful and systematic procedure for calculating modal eigenvaluess and modal fields to arbitrary orders in inverse powers of the large wavenumber k.
Asymmetric two-step GaAlAs quantum well for cascaded second-order processes

An asymmetric two-step GaAlAs quantum-well suitable for applications that employ the cascading second-order nonlinear effect is proposed. The existence of a large /spl chi//sub zzz//sup (2)/ (d/sub 33/) second-order susceptibility tensor based on transitions between the light hole and the conduction band at a wavelength of 1.55 /spl mu/m is demonstrated. The expression for /spl chi//sub zzz//sup (2)/ is obtained using the density matrix formalism and the envelope function approximation including the valence band-mixing model. The magnitude of the /spl chi//sub zzz//sup (2)/ is estimated to be of the same order as that of the bulk GaAs material and /spl chi//sub xzx//sup (2)/. >
Experiences with the subsumption architecture

A subsumption architecture has been proposed as an effective approach for the construction of robust, real-time control systems for mobile robots. To investigate its strengths and weaknesses, a simulation of the architecture was developed called the Subsumption Architecture Tool (SAT). This simulation allows various models of system behavior to be quickly built and tested. During the building and testing of the SAT, issues related to some architectural features became evident: level of commitment of each layer; code redundancy; problem decomposition and programming style; complexity of large system; and abstract reasoning capabilities. The effects of these issues are presented with respect to the design and implementation choices of two sample layers of behavior. These layers are used to illustrate considerations that need to be taken into account when a project team is considering the use of the subsumption architecture or when a subsumption-architecture-based system is being designed and implemented.<<ETX>>
Dual stress liner for high performance sub-45nm gate length SOI CMOS manufacturing

For the first time, tensile and compressively stressed nitride contact liners have been simultaneously incorporated into a high performance CMOS flow. This dual stress liner (DSL) approach results in NFET/PFET effective drive current enhancement of 15%/32% and saturated drive current enhancement of 11%/20%. Significant hole mobility enhancement of 60% is achieved without using SiGe. Inverter ring oscillator delay is reduced by 24% with DSL. Overall yield for the DSL process is comparable to that of a similar technology without DSL. Single and multi-core SOI microprocessors are being manufactured using the DSL process in multiple, high-volume fabrication facilities.
Optimization of pitch-split double patterning phoresist for applications at the 16nm node

Pitch-split resist materials have been developed for the fabrication of sub-74 nm pitch semiconductor devices. A thermal cure method is used to enable patterning of a second layer of resist over the initially formed layer. Process window, critical dimension uniformity, defectivity and integration with fabricator applications have been explored. A tone inversion process has been developed to enable the application of pitch split to dark field applications in addition to standard bright field applications.
Loss measurements in intermixed InGaAs/AlGaInAs multiple-quantum-well ridge waveguides

A study of the losses in InGaAs/AlGaInAs multiple-quantum-well ridge waveguides band edge shifted by quantum well intermixing is presented. The intermixing process is based on point defects generated on the sample surface during the deposition of sputtered SiO/sub 2/ and a subsequent rapid thermal annealing. It is demonstrated that for small wavelength shifts (60-80 nm), losses are considerably lower than in samples with maximum band edge shift (150 nm). Minimum losses of 6 dB/cm have been measured.
Aspects of the generation of finite-difference Green's function sequences for arbitrary 3-D cubic lattice points

The robust and speedy evaluation of lattice Green's functions LGFs) is crucial to the effectiveness of finite-difference Green's function diakoptics schemes. We have recently determined a generic recurrence scheme for the construction of scalar LGF sequences at arbitrary points on a 3-D cubic lattice. For this recurrence scheme, proper care must be taken to retain sufficient accuracy. For certain lattice points recurrence breakdown may occur at some discrete instant in time. Fortunately, this breakdown is rare, may be easily repaired, and does not seem to affect the LGF sequence behaviour. However, due to the anomalous wavefield behaviour induced by the discrete lattice, one must take care to work with time-domain signals that are sufficiently band-limited.
Analysis Of Harmonic (Sub-)THz Passive Mode Locking in Monolithic Compound Cavity Fabry-Perot and Ring Laser Diodes

The authors analyse harmonic mode-locking at (sub)terahertz frequencies in linear Fabry-Perot compound-cavity laser diodes (theoretically), and in ring structures (experimentally and theoretically) and compare these lasers with other constructions used for harmonic mode-locking.
Polarisation stability of optical solitons

Optical solitons are a topic of increasing importance with major applications in trans-oceanic communications (temporal solitons) and all-optical reconfigurable interconnects (spatial solitons). Initial investigations considered only single component solitons but research has advanced to considering the practicalities and problems of multi-component solitons. There are several possible implementations of this, including multiple wavelengths, but the most straightforward is based on the two orthogonal polarisation components. If the medium has a low birefringence then four-wave-mixing leads to an exchange of energy between the two components. We consider two examples of such systems employing a Kerr nonlinearity (1) temporal solitons in birefringent optical fibre and (2) spatial solitons in semiconductor slab waveguides.
Solitons in communications

Communications of tens of gigabits per second of data over distances of many thousands of kilometres using optical-fibre solitons has been predicted and demonstrated experimentally. This paper reviews the history, physics and engineering of optical-fibre solitons and assesses the problems encountered in realising the concept for high-capacity transatlantic telecommunications. The possibilities of communications inherent in the transmission of pulses which do not suffer dispersion were recognised almost immediately after the mathematical clarification of the soliton, and in 1973 a proposal was initiated by Hasegawa and Tappert for the use of this phenomenon for high-capacity digital communications along optical fibres. The technical issues involved in a proper understanding of this idea are discussed and the impact on technology that has followed the proposal is considered.
Time- and frequency-domain theory of externally synchronised operation of a passively mode-locked laser diode

calculations, based on a third order approximation for the chirp, show that the third order chirp coefficient, which can be evaluated from A& and higher order moments of the spectrum, is negligible, at least in the present experiment. This confirms the transform limited quality of the pulse. Possible applications of optimized pulses from gain-switched DFB lasers are all optical demultiplexing and soliton generation in ultrahigh bitrate communications. "CNR-Consiglio Nazionale delle Ricerche, Piazzalc Aldo Mom 7 00185 Roma, Italy
Process optimization for high electron mobility in nMOSFETs with aggressively scaled HfO/sub 2//metal stacks

The performance of aggressively scaled (1.4nm<T/sub inv/<2.1nm) self-aligned HfO/sub 2/-based nMOSFETs with various metal gate electrodes (W, TaN, TiN, and TaSiN) is optimized. It is shown that high mobility values, competitive with oxynitride controls (SiON/poly-Si, T/sub inv//spl sim/1.8-2.1nm), can be achieved. Detailed studies of the role of interface states, remote charges in the HfO/sub 2/ layer, interfacial layer regrowth, and nitrogen-induced charge lead to the conclusion that high-temperature-induced structural modifications near the SiO/sub 2//HfO/sub 2/ interface substantially improve the electron mobility.
Analysis of nonlinear optical-electromagnetic interactions in ultrafast mode-locked laser diodes

The operation of mode-locked (ML) semiconductor laser diodes (LDs), in common with lasers of other types, is a nonlinear process in which a balance of dispersion and various nonlinearities results in the generation of an ultrashort optical pulse, repeated at the cavity round-trip frequency or its harmonic and with parameters, averaged over a round-trip, constant, similar to an optical soliton. In this paper we theoretically analyse the fundamentals of high-frequency mode-locked laser diodes and their application to generating and/or frequency shifting ultrafast electrical signals.
Ion implant data log analysis for process control and fault detection

Data mining techniques have been introduced to the semiconductor industry in recent years. In this paper, we report on progress in developing a network based implant data log (IDL) data analysis system which can be used to access data from multiple tools and multiple recipes. The system that is currently under development can be used to generate individual control charts from any of over 100 process variables for a user selectable process recipe or from all implants in the database. Multi-variable models are being developed to compare relationships among process variables. These models calculate predicted values of process variables, and the differences between the model and the actual variables are used as indicators of process drift, hardware malfunctions, recipe integrity, and in some cases mis-processing.
Apparent 3-D finite-difference Green's function anomalies are features, not artefacts

We have previously reported on the use of Zeil-berger's algorithm to construct a third-order recurrence scheme with polynomial coefficients of the sixth degree, by which 2-D finite-difference time-domain (FDTD) Green's function sequences can be generated on-the-fly. For 3-D cubic lattices, we have managed to find recurrence schemes for lattice points along the symmetry directions. In the non-diagonal symmetry directions, an apparently strong secondary signal peak occurs. A group-delay analysis associated with the characteristic variety of a spectral integral representation for the FDTD Green's function leads to curves that coincide with the ones in its spectrogram resulting from a Gabor transformation, indicating that the anomalies are rapidly oscillating local features rather than artefacts.
Discrete Green's function diakoptics for stable FDTD interaction between multiply-connected domains

We have developed FDTD boundary conditions based on discrete Green's function diakoptics for arbitrary multiply-connected 2D domains. The associated Z-domain boundary operator is symmetric, with an imaginary part that can be proved to be positive semi-definite on the upper half of the unit circle in the complex Z-plane. Through Schwarz' exterior formula an integral representation of this operator is obtained that is analytic outside that unit circle. A quadrature-rule based rational approximation of the operator corresponds to a self-consistent finite-lookback scheme in the discretised time domain. This scheme is demonstrably stable, in that only secular, non-growing, source-free solutions remain, which may be suppressed.
Adaptive quadtree coding of motion-compensated image sequences for use on the broadband ISDN

An image-coding technique is described in which an adaptive quadtree scheme is used to encode motion-compensated difference images. A mechanism is determined within the encoding process that allows a predetermined level of image quality to be selected by the user at call setup time and then maintained by the encoder. The coder operates in a variable-bit-rate mode providing a video service of near-constant image quality. A multilayered version of the coding scheme is also described in which the degradation caused by cell loss during transmission can be limited in its effect and removed completely within a short period of time. The recovery from cell loss is achieved by sending blocks from the original image sequence whenever cells are known to have been deleted by the local-network access node.
Intrinsic mode theory of conical corrugated horns

The application of the concept of intrinsic modes to the theory of propagation in conical corrugated horns is developed. An intrinsic mode is an exact solution of source-free Maxwell equations which satisfies the boundary conditions to a prescribed order of accuracy as the flare angle alpha becomes small. There exists an infinite number of intrinsic modes for a given structure and each one corresponds with a fixed local normal mode at every cross-section, to which it approximates asymptotically as alpha to 0. An intrinsic mode is given by a Fourier-like spectral integral which is uniformly valid, including the regions where the corresponding local normal mode is evanescent or in transition from propagating to evanescent. This spectral integral can be generated from knowledge of only one local normal mode at each cross section, and numerical calculations show that the intrinsic mode based on the HE/sub 11/ local normal mode is sufficient for many applications, including the calculation of crosspolar radiation.
Sinusoidal Currents in Linearly Tapered Loaded Transmission Lines

Working formulas for the calculation of input impedances and attenuation are obtained for a transmission line in which the resistance and inductance per unit length are linear functions of distance, and in which the capacitance and leakance are constant. Generalized functions depending on the initial constants and the rate of taper are introduced, in such a way that the formulas and the functions are analogous to the usual formulas and hyperbolic functions. The latter are secured as special cases of the former. The theory is applicable to the tapered loaded submarine cable. Propagation in such a transmission line, as distinguished from that in the smooth uniform line, is characterized by the fact that the current attenuation is, in general, different from the voltage attenuation.
Application of 3D finite-difference time-domain (FDTD) method to predict radiation from a PCB with h

The authors have applied the 3D FDTD technique to simulate the propagation of electrical signals within printed circuit boards (PCBs). This relates to the work currently being carried out into the propagation of very high speed digital pulses in PCBs for high bandwidth systems. Visualisation of an applied Gaussian pulse from multiple sources within and outwith a PCB is shown and the techniques used to determine the system characteristics are discussed.