Single-channel Structure Research Articles

Design and experiment study of a novel dual-channel independent-coil magnetorheological grease damper

In order to address the issue of reduced damping force dynamic range in magnetorheological (MR) damper caused by the high zero-field viscosity of MR grease, known for its sedimentation stability, this paper introduces a novel dual-channel independent-coil MR damper (DCICMRD). Firstly, the dual-channel configuration and the magnetic circuit structure of independent coils were meticulously designed, and a genetic algorithm was employed to conduct multi-objective optimization of the structural parameters for DCICMRD. The optimization results indicate that all performance metrics of the damper post-optimization exhibit improvements exceeding 15%. Then, the theocratical model of the damping force for DCICMRD under three operational modes are established, and the output damping force of various input currents for different operating mode is obtained. Finally, the DCICMRD was manufactured and subjected to dynamic performance testing. The results revealed that the damping force dynamic range in Mode III, i.e. dual-channel structure, can achieve approximately 15 times, whereas Mode I, i.e. traditional single-channel structure, only attains approximately 9 times. The aforementioned research holds significant implications for expanding the further engineering applications of MR dampers.

Emission Reduction and Channel Decisions in a Two-Echelon Supply Chain Considering Service Spillovers

The development of e-commerce and the green economy has prompted suppliers of green products to introduce internet channels by which products are directly sold to consumers. However, the emergence of “price wars” and “free riding” between the two channels after the introduction of online channels may affect the stability of the green supply chain. This paper uses optimization theory to investigate the impact of service spillover effects and different channel structures on the optimal decision of supply chain members in a Stackelberg game. By comparing the equilibrium outcomes of the single-channel and dual-channel supply chain in a setting with and without retail services, we observe that the supplier prefers to encroach on the market when services that retail locations provide largely spillover to and benefit the direct sales channel. Contrary to popular belief, a higher degree of service spillovers is beneficial for the retailer to achieve more returns under the dual-channel structure, whereas supplier encroachment will lead to a decline in the service level if the spillover degree is relatively low. In addition, the emission reduction level of products under supplier encroachment is always higher than that employed in the single-channel structure if consumers have both low-carbon preference and a high degree of service sensitivity. Finally, we expand our discussion by introducing the carbon cap-and-trade (CCT) mechanism to compare the conditions for achieving Pareto improvement under supplier encroachment. These results can provide helpful insights for decision-makers in supply chain management to implement effective channel selection and achieve sustainable development.

Simulation of a multichannel vacuum transistor with high cut-off frequency

A multichannel vertical vacuum transistor based on the Fowler–Nordheim tunneling emission mechanism was proposed and numerically investigated. The multichannel structure was demonstrated to be effective in enhancing the drain current when compared to the traditional single-channel structure with the same device size. For example, transconductance increased from 0.42 mS of the single-channel structure to 0.86 mS of the four-channel structure. In addition, when the vacuum channel number increases, the size of a single channel decreases correspondingly, leading to a reduction in electric field intensity on the electron emission surface. Thus, the off-state current dramatically reduced by two orders of magnitude reaching10−15 A according to the simulated results. In other words, the ON/OFF drain current ratio of the multichannel structure is significantly enhanced. Furthermore, the simulation results indicate that the cut-off frequency of the multichannel device is 33% higher than that of the traditional single-channel one reaching 0.19 THz.

Parallel dual-channel multi-label feature selection

In the process of multi-label learning, feature selection methods are often adopted to solve the high-dimensionality problem in feature spaces. Most existing multi-label feature selection algorithms focus on exploring the correlation between features and labels and then obtain the target feature subset by importance ranking. These algorithms commonly use single-channel structure to obtain important features, which induces the excessive reliance on the ranking results and causes the loss of important features. However, the correlation between label-specific feature and label-instance is ignored. Therefore, this paper proposes Parallel Dual-channel Multi-label Feature Selection algorithm (PDMFS). We first introduce the concept of dual channel and design the algorithm model as two independent modules. The algorithm obtained different feature correlation sequences, thus avoided relevant feature loss. And then, the proposed algorithm uses the subspace model to select the feature subset with the maximum correlation and minimum redundancy for each sequence, thus obtaining feature subsets under respective correlations. Finally, the subsets are cross-merged to reduce the important feature loss caused by the serial structure processing single feature correlation. The experimental results on eight datasets and statistical hypothesis testing indicate that the proposed algorithm is effective.

Measurement of Rb isotope ratio by atomic absorption spectroscopy with multi-microchannel array structure cavity

Rubidium (Rb) isotope analysis has important applications in geological exploration and environmental detection. Based on tunable laser atom absorption spectroscopy technology combined with thermal decomposition of the sample, a Rb isotope absorption spectroscopy measurement device is built to detect the Rb isotope ratio stability. And the atomic generator is designed by a new micro-channel array structure, which enhances atomic beam collimation capability, effectively suppresses the doppler effect of the spectrum, and improves the resolution of Rb isotope absorption spectrum. The device adopts tantalum metal to make the atomic generator with a diameter of 6 mm, and the micro-channel array with a diameter of 1 mm is stacked inside the atomic generator which can be heated resistively to 3000 ℃. In this experiment, the Rb carbonate sample is catalyzed to release Rb atom beam at a high temperature of 600 ℃, while a probe laser is used to obtain high resolution Rb absorption spectrum. The Rb isotope ratio (<sup>85</sup>Rb∶<sup>87</sup>Rb) of natural abundance Rb carbonate samples is 2.441±0.02 by combining the inversion of the spectral line parameters, the detection error is 5.9%, and the detection limit of <sup>87</sup>Rb is 1.76‰ (3<i>σ</i>). The experimental results show that the multi-microchannel structure reduces the linewidth of Rb atoms by 450 MHz (half height full width) compared with the counterparts of the single-channel structure, which can effectively distinguish the absorption characteristics of Rb isotopes. The device has a high detection accuracy and a high spectral resolution, which provides a possibility for the metal isotope abundance analysis, and has a broad application prospect.

Comparison of an opposed-piston free-piston engine using single and dual channel uniflow scavenging

• The OP2S-FPE using single-channel and dual-channel uniflow scavenging was proposed. • The CFD model of the engine was built, and simulation parameters were discussed. • The single-channel engine has advantages of fast heat release rate and low emission. • Energy loss comparisons between the single and dual channel engine was presented. • The single-channel uniflow scavenging combustor is suitable for the engine. The free-piston engine is an unconventional engine characterized by a free-moving piston without a crankshaft system. The scavenging process recharges the engine and is crucial to mixture formation and stable combustion. In this paper, a single-channel structure for a two-stroke opposed-piston free-piston engine was proposed. A comparative study of spray, combustion, emissions and energy balance was presented using computational fluid dynamics simulations. Grid independence and step sensitivity were discussed in order to improve the simulation accuracy. The results show that the combustion efficiency of the engine with single-channel structure increased to 98.1%, and the combustion duration decreased by 59.8%. Due to the successful combustion organization, the single-channel engine achieves low emissions even if the CO2 content is slightly higher. The thermodynamic analysis of the engine reveals that the energy loss from scavenging process contributes the largest part to the total energy loss. In addition, the study initially reveals the performance stability of the single-channel engine under different combustion conditions.

ПОЛУМАРКОВСКАЯ МОДЕЛЬ ТЕЛЕКОММУНИКАЦИОННОЙ СЕТИ С ДИНАМИЧЕСКИМ УПРАВЛЕНИЕМ

The paper proposes a semi-Markov model of telecommunication network. The variant of dynamictraffic control of queuing system as a special case of telecommunication network is considered.The main purpose of control is to minimize the average cost per unit of time to service theincoming flow of information (packets). This takes into account the different bandwidth of thechannels, the processing speed of information in the channel and the information capacity of thebuffers. The approach to the organization of dynamic control taking into account noise immunity(information reliability) and information security is discussed. The problem of dynamic control ofa telecommunication network is considered on the example of a simple single-channel structure ofthe “point-to-point” type, which is modeled as a linear unidirectional Markov chain. The parametersof the service tariff, the cost of the fine for refusal of service were introduced. The analysisallows us to make the following remarks that the distribution of the input information flow ofpackets is Poisson, the law of distribution of the length of packets and the speed of their arrival isexponential, which together characterizes the Markov process. However, there are concurrentservice delays relative to the timing of service requests, including buffer overflow delays. The proposedsemi-Markov model of a telecommunications network can be used for more complex networkstructures. In particular, for a telecommunication network, consisting not only of one singlechannelinformation transmission system (single-channel queuing system), but representing a setof several systems, that is, for multichannel telecommunication networks.

Non-extensitivity and criticality of atomic hydropathicity around a voltage-gated sodium channel’s pore: a modeling study

Voltage-gated sodium channels (NavChs) are pore-forming membrane proteins that regulate the transport of sodium ions through the cell membrane. Understanding the structure and function of NavChs is of major biophysical, as well as clinical, importance given their key role in cellular pathophysiology. In this work, we provide a computational framework for modeling system-size-dependent, i.e., cumulative, atomic properties around a NavCh’s pore. We illustrate our methodologies on the bacterial NavAb channel captured in a closed-pore state where we demonstrate that the atomic environment around its pore exhibits a bi-phasic spatial organization dictated by the structural separation of the pore domains (PDs) from the voltage-sensing domains (VSDs). Accordingly, a mathematical model describing packing of atoms around NavAb’s pore is constructed that allows—under certain conservation conditions—for a power-law approximation of the cumulative hydropathic dipole field effect acting along NavAb’s pore. This verified the non-extensitivity hypothesis for the closed-pore NavAb channel and revealed a long-range hydropathic interactions law regulating atom-packing around the NavAb’s selectivity filter. Our model predicts a PDs-VSDs coupling energy of sim !282.1 kcal/mol corresponding to a global maximum of the atom-packing energy profile. Crucially, we demonstrate for the first time how critical phenomena can emerge in a single-channel structure as a consequence of the non-extensive character of its atomic porous environment.

Numerical modeling of highly sensitive resonant detection of THz radiation using a multichannel dispersive plasmonic HEMT

The resonant detection of terahertz radiation using a dispersive AlN/GaN multichannel high-electron-mobility transistor (HEMT) is analyzed and modeled in this paper. The proposed full-wave model is based on the concurrent solution of the complete hydrodynamic model (CHM) and Maxwell’s equations. The CHM is derived from the first three moments of the Boltzmann transport equation (BTE). Considering the variations of the electron temperature and transport parameters along the HEMT channel, this model well characterizes the electron–wave interaction in the device for both low- and high-field conditions. Moreover, the effect of the optical phonon modes of the GaN buffer, which cannot be ignored in the target terahertz frequency band, is described using the Lorentz dispersive model. Employing the developed model, the transmission spectrum of the device is extracted numerically using the finite-difference time-domain (FDTD) method for grating-gate single-, double-, and three-channel HEMT structures. The results show that, at a lattice temperature of 300 K for a GaN grating-gate HEMT with gate periodicity of 680 nm and gate width of 520 nm, at given resonance frequency and overall electron concentration, the resonance depth improves by about 2.7 dB in the three- compared with the single-channel structure. Moreover, it is shown that the detection performance of such a structure at 300 K is similar to the single-channel HEMT at a reduced temperature of 120 K. Therefore, the multichannel HEMTs can show notably improved resonant detection performance, enabling the design of resonant detectors with enhanced sensitivity at room temperature.

A Novel Single-Channel Arrangement in Chirp Transform Spectrometer for High-Resolution Spectrum Detection

Chirp transform spectrometer (CTS) has become a powerful tool widely used in spectral analysis nowadays. In this paper, a novel single-channel structure of Chirp transform spectrometer for high-resolution spectrum detection is developed. By adding an additional signal source, a mixer, a power divider, and a combiner, one channel of the classical CTS is replaced and the matching problem between the two channels is avoided. The circuit principle and characteristics of the novel single-channel structure are presented. Two simulation models with ideal devices and nonideal devices for the classical two-channel CTS structure and the improved single-channel structure are built to verify the effectiveness of the novel structure. Simulation results show that the time distributions of the obtained compression pulses resulting from the improved structure are the same as that from the classical two-channel CTS. The obtained amplitudes and spectral resolution are almost the same in both structures with ideal devices. The introduced nonideal devices mainly influence the amplitudes of the output pulses. In addition, an experiment with hardware implementation is verified on real chains. The influence of nonideal devices is measured and analyzed. Compared to the classical two-channel structure of CTS, the modified one-channel arrangement avoids the matching problem between different channels and saves devices.

Multi-Temporal Ultra Dense Memory Network for Video Super-Resolution

Video super-resolution (SR) aims to reconstruct the corresponding high-resolution (HR) frames from consecutive low-resolution (LR) frames. It is crucial for video SR to harness both inter-frame temporal correlations and intra-frame spatial correlations among frames. Previous video SR methods based on convolutional neural network (CNN) mostly adopt a single-channel structure and a single memory module, so they are unable to fully exploit inter-frame temporal correlations specific for video. To this end, this paper proposes a multi-temporal ultra-dense memory (MTUDM) network for video super-resolution. Particularly, we embed convolutional long-short-term memory (ConvLSTM) into ultra-dense residual block (UDRB) to construct an ultra-dense memory block (UDMB) for extracting and retaining spatio-temporal correlations. This design also reduces the layer depth by expanding the width, thus avoiding training difficulties, such as gradient exploding and vanishing under a large model. We further adopt multi-temporal information fusion (MTIF) strategy to merge the extracted temporal feature maps in consecutive frames, improving the accuracy without requiring much extra computational cost. The experimental results on extensive public datasets demonstrate that our method outperforms the state-of-the-art methods by a large margin.

Improvement in IGZO-based thin film transistor performance using a dual-channel structure and electron-beam-irradiation

We investigated the effects of electron-beam-irradiation (EBI) on amorphous indium gallium zinc oxide (IGZO) films deposited by RF magnetron sputtering. The device performance of thin film transistors (TFTs) fabricated from these films was also evaluated. We conducted transmission electron microscopy and x-ray photoelectron spectroscopy to analyze the microstructure and chemical state of the synthesized IGZO. The EBI-treated IGZO TFTs achieved higher carrier mobility and on/off ratio than conventionally annealed IGZO TFTs. In addition, we found that a dual-channel structure shows electrical characteristics superior to those of a single-channel structure, with a carrier mobility of 18.1 cm2/V · s.

Safety Critical Computer Systems: Failure Independence and Software Diversity Effects on Reliability of Dual Channel Structures

Abstract The paper examines Safety Critical real-time Systems (SCS), in particular their dual-channel structures. The analytical study on computer-based SCS recognizing failures comparing the results of both channels is based on the theory of reliability. The aim is to establish reliable models that include independence rate between failures of both channels and their diversity. The created formulas are used to calculate the function of reliability, probability of safety failures and hazard failures. The intensity of failures of the system and the intensity of its recovery, the ratio between Common Mode Failures (CMF) and failures of individual channels are explicitly presented in the models. for the independence of hardware and software Faults are introduced. The analytical models obtained allow evaluating the effects of independence of channels and the depth of their diversity. A formula for calculating the improvement of safety thanks to the dual-channel architecture in comparison to a single-channel structure of the same output reliability parameters has been worked out. Analytical models can be used to calculate indicators of systems in order to establish their compliance with safety standards. Analytical models can be used to calculate indicators of specific systems to determine their compliance with safety standards. The results make possible to find out technical solutions with better reliability and safety features.

Characterization of the Primo-Vascular System in the Abdominal Cavity of Lung Cancer Mouse Model and Its Differences from the Lymphatic System

Cancer growth and dissemination have been extensively studied for a long time. Nevertheless, many new observations on anatomy and histopathology of cancer events are still reported such as formation of a vasculogenic-like network inside aggressive tumors. In this research, new kinds of micro-conduits, named primo-vessels, were found inside the abdominal cavity of NCI-H460 lung cancer murine xenograft models. These vascular threads were largely distributed on the surfaces of various organs and were often connected to peritoneal tumor nodules. Histological and immunofluorescent investigations showed that the primo-vessels had characteristic features that were distinctively different from those of similar-looking lymphatic vessels. They had multiple channels surrounded with loose collageneous matrices, which is in contrast to the single-channel structure of other vascular systems. The rod-shaped nuclei aligned longitudinally along the channels were assumed to be the endothelial cells of the primo-vessels, but LYVE-1, a specific marker of lymphatics, was not expressed, which indicates a clear difference from lymphatic endothelial cells. Taken together these findings on and characterization of the novel threadlike vascular structures in cancer models may have important implications for cancer prognosis and for therapy.

Single-channel imaging receiver for optical wireless communications

A novel and simple single-channel imaging receiver for high-speed portable wireless infrared communications is proposed. The receiver is able to aim automatically at the ceiling areas with better signal-to-noise ratio. The self-orienting capability, together with the very narrow field of view employed, drastically reduces the path loss, background noise and multipath distortion. Moreover, its single-channel structure minimizes hardware complexity in contrast to conventional angle diversity receivers. Our simulation results indicate that the proposed receiver, operating in a multispot diffusing configuration, offers significant gains in power requirements and channel bandwidth compared to angle diversity receivers.

Characteristics of In0.52Al0.48As/InxGa1−xAsyP1−y/In0.52Al0.48As high electron-mobility transistors

In 0.52 Al 0.48 As/In x Ga 1−x As y P 1−y / In 0.52 Al 0.48 As high electron-mobility transistors with single-channel and triple-channel structures were successfully fabricated by low-pressure metal-organic chemical-vapor deposition. The single-channel structure exhibits higher transconductance and drain-source saturation current than the triple-channel due to the higher average-carrier saturation velocity and sheet-carrier concentration of the In0.53Ga0.47As channel. The triple-channel structure is employed to take advantage of both the high electron mobility of In0.53Ga0.47As and the low ionization coefficient of InP. A third quaternary In0.72Ga0.28As0.61P0.39 (Eg∼0.95 eV) layer is introduced between In0.53Ga0.47As (Eg∼0.75 eV) and InP (Eg∼1.35 eV) channels to improve the electron-transport characteristics. Experimentally, the investigated triple-channel structure exhibits a low leakage current, a high breakdown voltages and a high linear-operation regime.

Single-channel correlators and residue calculus

Some simple (namely, single-channel) correlation functions involving an arbitrary number of fields are computed by means of a direct application of the residue calculus, through partial fraction expansions. Examples are presented in minimal models and parafermionic conformal theories. A generic factorized expression is deduced for the corresponding single-channel structure constants.

Self-consistent calculation of electron density in a two-channel modulation-doped structure

A method of self-consistent calculation of energy levels, electron density and conduction band-edge profile is described. Schrödinger's equation is solved by using a variational approach that reduces it to a matrix equation. The solution of the matrix eigenvalue problem gives all the solutions and eigenenergies for a given conduction band-edge profile. Poisson's equation is then solved to get the new profile and the procedure is repeated till convergence is reached. The results of application of this method to two structures are described. One is a single-channel modulation-doped structure and the other is a two-channel modulation doped structure. The calculation is carried out for the AlGaAs-GaAs material system. The implications of this calculation on device performance are pointed out. The two-channel structure is expected to result in higher drain currents but about the same transconductance value as the single-channel structure. Possible complications in applying this procedure to more complex structures are discussed.