Multistage Ring Research Articles

Exploring the Usage of Fast Carry Chains to Implement Multistage Ring Oscillators on FPGAs: Design and Characterization

Exploring the Usage of Fast Carry Chains to Implement Multistage Ring Oscillators on FPGAs: Design and Characterization

Design and Optimization of Multi-Stage TMR Sensors for Power Equipment AC/DC Leakage Current Detection

Tunnel magnetoresistance (TMR) can measure weak magnetic fields and has significant advantages for use in alternating current/direct current (AC/DC ) leakage current sensors for power equipment; however, TMR current sensors are easily perturbed by external magnetic fields, and their measurement accuracy and measurement stability are limited in complex engineering application environments. To enhance the TMR sensor measurement performance, this paper proposes a new multi-stage TMR weak AC/DC sensor structure with high measurement sensitivity and anti-magnetic interference capability. The front-end magnetic measurement characteristics and interference immunity of the multi-stage TMR sensor are found to be closely related to the multi-stage ring size design via finite element simulation. The optimal size of the multipole magnetic ring is determined using an improved non-dominated ranking genetic algorithm (ACGWO-BP-NSGA-II) to derive the optimal sensor structure. Experimental results demonstrate that the newly designed multi-stage TMR current sensor has a measurement range of 60 mA, a fitting nonlinearity error of less than 1%, a measurement bandwidth of 0–80 kHz, a minimum AC measurement value of 85 μA and a minimum DC measurement value of 50 μA, as well as a strong external electromagnetic interference. The TMR sensor can effectively enhance measurement precision and stability in the presence of intense external electromagnetic interference.

Residual Strength of Weakly Cemented Kaolin Clay in Multi-stage Ring Shear Test

Residual Strength of Weakly Cemented Kaolin Clay in Multi-stage Ring Shear Test

Residual shear strength of unsaturated soils via suction-controlled ring shear testing

Results from a comprehensive series of suction-controlled ring shear tests, conducted on statically compacted specimens of silty clayey sand and silty sand, are presented. The experiments were accomplished in a newly developed servo/suction-controlled ring shear apparatus suitable for testing unsaturated soils under large deformations and suction-controlled conditions via the axis-translation technique. The present work focuses primarily on two crucial aspects of compacted unsaturated soil behavior, namely, the behavior of silty clayey sand under suction-controlled ring shear testing, and the effects of pre-shearing and suction histories on unsaturated residual shear strength of compacted silty sand. Test results corroborate the important role played by matric suction on residual shear strength properties of unsaturated soils. For the range of net normal stresses and suction states investigated, the increase in residual shear strength with increasing suction was confirmed to be a linear trend for silty sand, but significantly nonlinear for silty clayey sand. Results from multi-stage ring shear tests confirmed that the residual shear strength of unsaturated soils is virtually independent of the pre-shearing and suction histories experienced by the soil.

Wavelength-Offset Filtering in Optical OFDM IMDD Systems Using Directly Modulated DFB Lasers

In optical OFDM (OOFDM) intensity-modulation and direct-detection (IMDD) single-mode fibre transmission systems using directly modulated DFB lasers (DMLs), wavelength-offset optical filtering considerably improves extinction ratios of OOFDM signals. However, optical filter-induced group delays bring about OOFDM signal spectrum distortions. Detailed investigations show that group delays associated with super Gaussian optical bandpass filters (OBPFs) significantly reduce both the dispersion tolerance and achievable optical power budget (OPB) of the system. To solve such a challenge, two simple approaches are proposed including combined optical filtering by using a ring resonator filter after a super Gaussian OBPF, and cascaded optical filtering by using multi-stage ring resonator filters. It is shown that, by optimizing ring resonator filter parameters, the proposed approaches can completely eliminate the filter group delay effect and enable 7 dB OPB improvements.

Analytical Treatment of Parametric Effects in a Ring Resonator

We propose two systems of a nano-waveguide to study the effects of ring resonator radii and coupling coefficient. The first proposed system is introduced as a single ring resonator. The change of the center wavelength from the output signal is monitored and analyzed. It shifts towards higher wavelength of the spectrum. The multistage ring resonator system consists of two micro and a nano ring resonators that can be integrated into a single system. The soliton pulse propagating within a Kerr type nonlinear medium is used to generate the large bandwidth signals. By using the suitable parameters, for instance, the input power of soliton, coupling coefficients, and ring radii, the short-wave and millimetre-wave output signals can simultaneously be generated in a multi-stage ring resonator (MMRR). We found that by using the MMRR, a desired response can be achieved over a broader portion of the spectrum compared to the single-stage ring resonator (SMRR) in which it is more preferable in applications.

Attosecond Pulse and Beyond Generation Based on Multi-Stage Micro Ring Resonators

We firstly propose the simple system of an attosecond light pulse generation by using a soliton pulse circulating in the integrated micro ring devices. The ultra short pulse in the atto scale regime and its beyond can be easily generated. Simulation results obtained have shown that the generation of a very narrow pulse and sharp tip is achieved. In principle, light pulse known as soliton pulse is input into a three stage micro ring resonators, where the ring radii are within the range from 5-15 microns. With some selected parameters such as ring radius, coupling ratio and nonlinear refractive index, the attosecond pulse is generated and achieved. The potential applications of using such a narrow pulse for new generation optical lithography, high density CD writing, high resolution interferometer, surface roughness and high speed optical computing, quantum computing are discussed.

Objective Oriented Multistage Ring Shear Test for Shear Strength of Landslide Soil

Ring shear tests were conducted on five samples of different nature with a modified Imperial College type ring shear machine. The three different testing methods used, (1) individual sample testing for each normal stress, (2) increasing load multistage ring shear test, and (3) reducing load multistage ring shear test, all showed similar effective residual internal friction angle for the samples, irrespective of testing method. However, effective residual shear intercept was different according to the testing methodology. The internal friction angle did not vary, particularly after the first minimum point in the stress displacement curve, although the residual shear intercept decreased with increase in the displacement. The thickness of the shearing zone increased along with the displacement. The remolded peak shear strength for saturated conditions at field dry density varied with the consolidation history. Measurement of remolded peak shear strength was possible in a single sample using the increasing load multistage ring shear test at normal consolidation. The equilibrium water content of the sample after the ring shear test was nearly equal to the plastic limit.

Investigation on the Added Mass and Added Damping of a Circular Cylindrical Structure Enclosed in a Container with Narrow Passage (Study Using a Rigid Body Model)

A neutron reflector, a newly designed core internal structure, is supposed to be adopted to the advanced pressurized water reactor (=APWR). This neutron reflector is composed of multi-stage ring type structures and is installed in a core barrel with very narrow passages at the 4 corner portion. Thus, it is considered that the coupling effect with a core barrel through liquid will become very predominant due to very large added mass and added damping effects. The authors have evaluated the added mass and added damping using a simplified neutron reflector model which is a rigid, one-degree of freedom model, and systematically investigated the effects of various parameters such as frequency, liquid temperature, and so on. This report summarizes those results as a knowledge data base.

Multiwavelength optical signal processing using multistage ring resonators

We show that all-pass filters based on multistage ring resonators can be used to perform optical signal processing. In particular, using numerical simulations, we demonstrate their use for performing real-time Fourier transformation and for pulse repetition rate multiplication (temporal Talbot effect) simultaneously over multiple wavelength signals.

Multistage ring network: An interconnection network for large scale shared memory multiprocessors

Abstract Unidirectional ring-based networks are currently popular choices for high performance large scale shared memory multiprocessors. This class of networks is attractive for their simple hardware interfaces, high speed communication, wider data path, and easy addition of extra nodes. However, a single ring does not scale well due to the fixed bandwidth, and the hierarchical ring networks as a natural extension of a single ring show limited scalability due to their limited bandwidth near the root. In this paper we present a new interconnection network called the Multistage Ring Network (MRN). The MRN has a 2-level hierarchy of rings, and its interconnection of global rings forms a type of the multistage network. The architecture of the MRN is effective at diffusing the global traffic on the network to all global rings, and the bandwidth of the network increases proportionally with increases in the system size. Our results show that in a peak throughput, the MRN performs seven times better than the hierarchical ring network for system size of 1024.

Preparation of Ultrafine Silicon Nitride, and Silicon Nitride and Silicon Carbide Mixed Powders in a Hybrid Plasma

Ultrafine Si3N4 and Si3N4+ SiC mixed powders were synthesized through thermal plasma chemical vapor deposition (CVD) using a hybrid plasma which was characterized by the superposition of a radio‐frequency plasma and an arc jet. The reactant, SiCl4, was injected into an arc jet and completely decomposed in a hybrid plasma, and the second reactant, CH4 and/or NH3, was injected into the tail flame through multistage ring slits. In the case of ultrafine Si3N4 powder synthesis, reaction effieciency increased significantly by multistage injection compared to single‐stage injection. The most striking result is that amorphous Si3N4 with a nitrogen content of about 37 wt% and a particle size of 10 to 30 nm could be prepared successfully even at the theoretical NH3/SiCl4 molar ratio of ∼ 1.33, although the crystallinity depended on the NH3/SiCl4 molar ratio and the injection method. For the preparation of Si3N4+ SiC mixed powders, the N/C composition ratio and particle size could be controlled not only by regulating the flow rate of the NH3 and CH4 reactant gases and the H2 quenching gas, but also by adjusting the reaction space. The results of this study provide sufficient evidence to suggest that multistage injection is very effective for regulating the condensation process of fine particles in a plasma tail flame.

Effect of Testing Procedure in Ring Shear Tests

Abstract This technical note describes a comparison between the results obtained from single-stage and multistage ring shear tests on two different types of normally consolidated clay. The results confirm the brittle behavior of normally consolidated soils containing a high proportion of clay particles and the curved nature of the residual stress failure envelope. Detailed examination of the test data shows that while the multistage technique offers a considerable advantage in terms of the test duration, it may give erroneous results for soils with a high proportion of platy clay particles.

Investigation into the multi-stage ring rolling of aluminium bicycle wheel rims

A method of producing bicycle wheel rims by expanding small diameter ring blanks in a ring rolling mill offers potential advantages over existing methods of rim production, which involve the circling and jointing of lengths of extruded section. The paper describes feasibility studies of the ring rolling method, the work having been sponsored by a cycle manufacturer. The required rim profile could not be formed in one rolling stage, from a simple form of ring blank, and a multi-stage rolling process was developed. The design of the forming rolls is described and problems encountered in achieving sound products of the required accuracy are discussed.

Ion-implanted ESFI MOS devices with short switching times

Switching times of complementary MOS devices realized with epitaxial silicon films on insulators (ESFI) are reduced by using a self-aligning technique with ion implantation, since the gate overlapping capacitances and therefore the so-called Miller capacitances, are reduced thereby. Switching times and power dissipation have been measured using multistage ring oscillators. Stage-delay times of 500 ps at a supply voltage of 10 V (800 ps at 5 V), and power-delay products of 0.5 pJ at 5 V, have been obtained at five-stage ring oscillators with a channel length of about 3 /spl mu/m. Calculated and measured results are compared, and a simple formula for calculating the influence of the Miller capacitance on the switching times is indicated.

Silicon controlled rectifier static alternators

The paper gives a general introduction to a new technique of using silicon controlled rectifiers in ring counters for polyphase sine-wave generation based on the experimental observation that such waveforms occur across diametrically opposite output terminals of a multistage ring counter having an optimum network geometry. A specific application of this-principle in the form of a d.c. to 3-phase a.c. sinusoidal inverter is then described in detail, the design and evaluation data of a prototype 30 V d.c. to 240 V, 60 VA per phase unit operating at 400c/s being presented as an example of practical design.