Modulation Coefficient Research Articles

On Lusztig’s Character Formula for Chevalley Groups of Type Al

For a Chevalley group G over an algebraically closed field K of characteristic p>0 with the irreducible root system R, Lusztig’s character formula expresses the formal character of a simple G-module by the formal characters of the Weyl modules and the values of the Kazhdan–Lusztig polynomials at 1. It is known that, for a sufficiently large characteristic p of the field K, Lusztig’s character formula holds. The known lower bound of the characteristic p is much larger than the Coxeter number h of the root system R. Observations show that for simple modules with restricted highest weights of small Chevalley groups such as those of types A1,A2, A3,B2, B3, and C3, Lusztig’s character formula holds for all p≥h. For large Chevalley groups, no other examples are known. In this paper, for G of type Al, we give some series of simple modules for which Lusztig’s character formula holds for all p≥h. Using this result, we compute the cohomology of G with coefficients in these simple modules. To prove the results, Jantzen’s filtration properties for Weyl modules and the properties of Kazhdan–Lusztig polynomials are used.

Generation and control of circular Airy solitons in fractional nonlinear optical systems under different modes.

In this paper, the dynamics of the circular Airy beam (CAB) in the spatial fractional nonlinear Schrödinger equation (FNLSE) optical system are investigated. The propagation characteristics of CABs modulated by the quadratic phase modulation (QPM) in a Kerr (cubic) nonlinear medium under power function diffractive modulation modes and parabolic potentials are numerically simulated by using a step-by-step Fourier method. Specifically, the threshold for CABs to form solitons in the Kerr medium is controlled by the Lévy index and the QPM coefficient. Secondly, the parabolic potential has the ability to stabilize the FNLSE optical system, making it easier for the formation of CAB solitons. The addition of QPM allows the refocusing of the split beam caused by the Lévy index, and it can change the position and intensity of solitons. Finally, we also study the transmission evolution of QPM-modulated CABs in the Kerr medium under the power function diffraction modulation mode. We can obtain different types of solitons by varying the power function modulation coefficients. A dark soliton with high stability is formed, and we can control its size. Results show that it is possible to optimize the parameter settings (parabolic potential coefficients, power function modulation coefficients, QPM coefficients, Lévy indices, and nonlinear Kerr intensity coefficients) to obtain different types of solitons as well as to modulate the soliton transport. It provides more degrees of freedom for the study of CAB soliton propagation in the Kerr media, which is of great significance and application in fields of nonlinear optical transport, particle manipulation, and optical metrology.

Dynamics of Airyprime beams with higher-order spectral phase modulation in the fractional Schrödinger equation

In this paper, the effects of spectral phase modulation on propagation characteristics of Airyprime beams modeled by fractional Schrödinger equation are studied, and the propagation dynamics of Airyprime beams are analyzed. It is found that the second and third-order spectral phase modulation significantly affect the beams dynamics. For the second-order spectral phase modulation, an increase in the Lévy index leads to a forward shift of the peak position, and the peak intensity increases for the positive spectral modulation coefficient, while the opposite tendency of the peak intensity is found for the negative spectral modulation coefficient. In addition, the appearance of multiple peaks depends on the positive modulation coefficient. For the third-order spectral phase modulation, the peak intensity increases under the larger spectral phase modulation coefficient with the backward shift of the maximum peak position, and an increase of the Lévy index results in the forward shift of the focusing position. The results show potential applications of Airyprime beams in various fields such as optical controlling and manipulation.

MTD precise jamming technology based on intra-pulse and inter-pulse frequency-phase joint modulation

For moving target detection (MTD) radar, existing jamming systems face problems such as poor controllability and strong regularity of two-dimensional false target characteristics. Time-frequency-phase modulation technology has great potential for active jamming and has received widespread attention. In this article, we propose a precise jamming method based on intra-pulse and inter-pulse frequency-phase joint modulation to control the two-dimensional distribution of false targets. First, construct periodic phase and segmented frequency modulation functions. Secondly, the intra-pulse phase modulation period Ts1 and frequency modulation amount ξl1 accurately control the positions of multiple false targets; the inter-pulse phase modulation period Ts2 and frequency modulation amount ξl2 accurately control the velocity of multiple false targets. Finally, the amplitude of the two-dimensional false target is accurately controlled by adjusting the phase modulation coefficient φi, phase modulation and frequency modulation duty cycles ηs, ηl. Compared with other jamming algorithms, the jamming distribution is more flexible and controllable, which verifies the superiority of this method.

Analysis of multi-criteria recommendation system based on fuzzy algorithm

There is a gap in defining the multi-criteria decision-making issues and with recommendation techniques and theories that can help develop the modulation coefficient recommenders. The main objective of this research is to identify an in-depth examination of the category of multiple variables recommendation systems. The methodology that is used in the current study is fuzzy multi-critical decision-making to enhance the precision and appropriateness of the recommendations provided to users, and make recommendations by representing an individual's performance for the product as an ordered collection of rankings in addition to different parameters. The techniques used to make forecasts and produce recommendations using multi-criteria rankings are reviewed. In addition, we propose the multiple-criteria ranking algorithms. Experimental evaluations demonstrated that our proposed algorithms can solve the multi-criteria issues. Furthermore, the research considers unresolved problems and upcoming difficulties for the category of recommendations for multiple variables ratings.

Determination of phase components of impedance in the environments over hydrocarbon accumulation

Abstract The article presents a novel method for hydrocarbon accumulation exploration based on determining the phase components of impedance in environments over hydrocarbons. Experimental studies were conducted at the Rechitsa hydrocarbon field and Osipovichi underground gas storage. The phase characteristics of surface impedance of hydrocarbon accumulation were measured using amplitude-frequency-modulated signals. The results show that determining two components of surface impedance in this mode significantly improves the accuracy of hydrocarbon boundary determination. The developed method can be implemented at frequencies of 0.1-2 GHz, using modulation frequencies of 10-100 MHz, amplitude modulation coefficients of 0.1-1.0, and frequency modulation indices of 20-95. The findings of this research can be applied in electrical exploration for prospecting hydrocarbon accumulation.

Experimental study on a novel split thermoelectric cooler of big temperature difference for combined cooling and heating supply

The improvement in maximum temperature difference is very important for thermoelectric cooler potential applications under severe and complex conditions. Currently, the maximum temperature difference of commercial single-stage thermoelectric modules represented is usually below 70 K and the energy efficiency is not high. In this paper, 12 kinds of split thermoelectric modules are developed according to different semiconductor and connector structures, and their performance is compared by experiments. The results show that the temperature difference of novel split thermoelectric cooler can exceed 200 K, which is more than 180 % higher than the currently commercial module (70 K), and it also has good performance under high ambient temperature. The new thermoelectric module can achieve the application of cold and hot ends energy on long-distance different occasions and has a module coefficient of performances of 2.68 and 1.29 under temperature differences of 57.43 K and 197.73 K, respectively. Meanwhile, a new asymmetric design method for independent control of hot and cold end temperatures is presented. It can achieve independent heat flux density design for cold and hot ends, and its performance can be further enhanced by regulating the temperature of connector.

The first cohomology of lie superalgebra P̃(2) with coefficients in kac modules

Over a field of characteristic p > 2, firstly, the structure of Kac modules of Lie superalgebra P ˜ ( 2 ) and the weight space decompositions are given. Secondly, the weight-derivations of P ˜ ( 2 ) to its Kac modules are computed. Finally, the first cohomology of P ˜ ( 2 ) with coefficients in Kac modules is determined.

Programmable delay cell based area efficient time-mode smart temperature sensor exploiting channel length modulation coefficient λ

This work presents an all-digital Programmable Delay Cell (PDC)-based time-domain smart temperature sensor exploiting the channel length modulation coefficient λ. For the first time the work has been described to establish the choice of multimode conversion options in the time-domain architecture of temperature sensor. The sensor incorporates a PDC and a time-to-digital converter (TDC) for the generation of temperature code. The different channel lengths of the PDC and Gated Ring Oscillator (GRO) delay elements of the TDC ensure the precise operation of the sensor. The proposed design provides a novel approach for the generation of variable resolution options having different sampling rates. At 90-nm CMOS process and 1.1 V supply voltage, the sensor occupies 0.015 mm2 and operates over a span of −60 °C to 120 °C. Additionally, multimode conversion time allows the sensor to be tuned to a small value of energy/conversion at 27 °C. This confirms to 0.38 nJ and 3.13 nJ at modes M0 and M7, respectively. Besides the sensor obtains a resolution 0.747 °C and 0.093 °C at a conversion time of 0.669 μs and 5.5 μs, respectively.

Recognition and separation of fringe patterns in deflectometric measurement of transparent elements based on empirical curvelet transform

In the deflectometric measurement of transparent elements, it is critical to separate the superposed fringes reflected from the front and rear surfaces to establish the pixel correspondences between the camera and screen pixels. But it is a challenging task due to the low reflectivity and uneven background of transparent elements. A reliable fringe separation method is proposed based on the empirical curvelet transform. The captured fringe images are decomposed into different modes according to their directions, periods, curvatures or modulation coefficients, and then a weighted-permutation-entropy-based fusing algorithm is developed to automatically aggregate those over-separated patterns. By employing the proposed method, the measurement accuracy is significantly improved, the number of demanded images is effectively reduced, and high-precision, automatic, and rapid measurement is thereby achieved. The measurement accuracy of spherical and cylindrical lenses can achieve 73 nm and 332 nm Root-of-Mean-Squares-Error, respectively.

Manipulating circular Airy beam dynamics with quadratic phase modulation in fractional systems under some diffraction modulations and potentials.

Based on a split-step Fourier algorithm, the transmission of circular Airy beams with quadratic phase modulation (QPM) is investigated in the fractional Schrödinger equation (FSE) under diffraction modulations (periodic modulation, linear modulation and power function modulation) and external potentials (parabolic potential and linear potential). The results show that QPM is able to change the focusing position and intensity, as well as the transmission trajectory of the beam. In a periodic modulation, the circular Airy beam (CAB) exhibits periodic variation characteristics, and the beam splitting is retarded under the action of the QPM. The self-focusing distance of the beam is significantly reduced, and its transmission trajectory and beam width are altered by the QPM under the linear modulation. The CAB progressively evolves into a non-diffraction beam under the power function modulation, and the QPM is able to reduce the light intensity and increase the beam width as the Lévy index decreases. In a parabolic potential, CABs display autofocusing and defocusing behavior, and the QPM affects the intensity distribution and optical width of the beam. The CAB is deflected and evolves periodically in a linear potential. The beam width increases and gradually stabilizes with the addition of the QPM. The propagation of CABs controlled with QPM in parabolic and linear potentials is also analyzed in the frequency domain. The results demonstrate that we can control the transmission of CABs in an FSE optical system by rationally setting parameters such as QPM, modulation coefficients, and external potentials.

Resonant fiber optic gyroscope driven by a broadband light source based on an over-coupled state fiber ring resonator

The resonant fiber optic gyroscope (RFOG) driven by a broadband light source has advantages over conventional RFOGs in terms of structure, solution, etc., and provides new ideas for the commercialization of RFOGs. In this paper, the basic working principle of RFOG driven by a broadband light source is introduced. The optimal modulation coefficients are provided for sinusoidal wave modulation. The influence of the length of the fiber-optic ring resonator (FRR) and the coupling coefficient of the fiber coupler on the sensitivity is analyzed. The FRR is constructed in the over-coupled state to improve the utilization of optical power, and thus significantly increase the system sensitivity. In experiments, an RFOG prototype with a diameter of 13 cm, a height of 7 cm, and a fiber ring length of 210 m is produced. A bias instability (BI) of 0.06°/h and an angular random walk (ARW) of 0.01∘/h are obtained.

P‐32: Dual Gate Amorphous Silicon Thin Film Transistor Technology for High Brightness and High Frame Rate Outdoor Display Panels

In this paper, we present the development of a dual‐gate (DG) architecture for hydrogenated amorphous silicon thin film transistors (a‐Si:H TFTs). The aim is to address the challenges of low on‐state current (Ion) and light‐induced degradation in traditional single‐gate (SG) TFTs. The experimental results demonstrate that the DG‐TFT exhibits significantly higher Ion compared to the SG‐TFT, and the improvement depends on the thickness of the top gate insulator. Additionally, the threshold voltage (Vth) can be adjusted by applying the top gate voltage, allowing for a full‐ swing modulation coefficient of approximately 0.2. To ensure long‐term stability, a light‐blocking layer has been incorporated as the top gate electrode, enabling the DG‐ TFT to maintain its initial properties even under intense illumination conditions of up to 28,000 nits.

Machine Learning-Based Figure of Merit Model of SIPOS Modulated Drift Region for U-MOSFET.

This paper presents a machine learning-based figure of merit model for superjunction (SJ) U-MOSFET (SSJ-UMOS) with a modulated drift region utilizing semi-insulating poly-crystalline silicon (SIPOS) pillars. This SJ drift region modulation is achieved through SIPOS pillars beneath the trench gate, focusing on optimizing the tradeoff between breakdown voltage (BV) and specific ON-resistance (RON,sp). This analytical model considers the effects of electric field modulation, charge-coupling, and majority carrier accumulation due to additional SIPOS pillars. Gaussian process regression is employed for the figure of merit (FOM = BV2/RON,sp) prediction and hyperparameter optimization, ensuring a reasonable and accurate model. A methodology is devised to determine the optimal BV-RON,sp tradeoff, surpassing the SJ silicon limit. The paper also delves into a discussion of optimal structural parameters for drift region, oxide thickness, and electric field modulation coefficients within the analytical model. The validity of the proposed model is robustly confirmed through comprehensive verification against TCAD simulation results.

An Algorithm for a Space-Vector Pulse Width Modulation with a Hybrid Switching Sequence for a Three-Level Neutral Point Clamped Voltage Source Inverter

This paper proposes a new algorithm for a space-vector pulse width modulation (SVPWM) with a hybrid switching sequence (SS) designed to control a three-level (3L) neutral point clamped (NPC) voltage source inverter (VSI). Based on the advantages of five-stage and seven-stage SS, we designed a hybrid SS to improve four key parameters in the system: inverter output current quality, neutral point (NP) and common-mode (CM) voltage levels, and switching losses of power switches. The proposed algorithm flexibly regulates meeting the four criteria depending on the system operating conditions by changing the regulation coefficient. The paper obtained an approximate dependence to determine the optimal regulation coefficient for any values of the inverter modulation coefficient when operating jointly with an active-inductive load. The effectiveness of the proposed algorithm is confirmed by computer simulation in the MatLab+Simulink environment, as well as the results of experimental studies. The paper presents the experimental dependences of static state spaces, including the distortion coefficient of higher current harmonics at the inverter output, the maximum error of the NP voltage, the number of switching pairs of power switches, and the pulse duty factor of CM voltage, depending on the inverter modulation coefficient and the regulation coefficient of the hybrid SS. The results showed that in the algorithm for a SVPWM with a hybrid SS, the number of switchings of power switches is reduced by an average of 13.5 % while maintaining the NP voltage balance and the quality of the curve at the inverter output at an acceptable level, close to a seven-stage SS (the deviations do not exceed 0.5 % and 0.2 %, respectively). The average CM voltage coefficient decreased by no more than 4.5 %. The indicators improve the energy saving, the weight-size parameters, and the operational reliability of the 3L NPC VSI. The application area of the algorithm is much wider and includes the control of power switches of active front ends, grid converters for electricity storage systems, active power filters, and power conditioners. DOI: https://doi.org/10.52783/pst.237

Buoyancy effects on very-large-scale motions and amplitude modulation in convective atmospheric surface layers

A large amount of high-Reynolds-number experimental data was obtained from long-term observations of the atmospheric surface layer in the Qingtu Lake Observation Array under different thermal stability conditions. To reveal the thermal effects, the variations of the scales of turbulent coherent structures, energy distribution and amplitude modulation as a function of thermal stability are investigated. Results show that in the convective atmospheric surface layer, the superposition of buoyancy and shear drives leads to a large enhancement of turbulent kinetic energy, an increase in the scales of coherent structures, and in particular, a more significant enhancement of the very-large-scale motions kinetic energy. This results in an increased energy proportion of very-large-scale motions, and thus enhancing the amplitude modulation effect on small scales. Moreover, the variations in the coherent structure scale, energy proportion of the very-large-scale motions, amplitude modulation coefficient and the corresponding modulating and carrier signal scales with the thermal stability parameter can all be characterized by the same parametric equation form. This study contributes to a better understanding of turbulence dynamics driven by both buoyancy and shear.

Oxygen-induced Ag-based binary structure for efficient heat-regulating windows

Heat-regulating (HR) windows are essential for net-zero-energy building approaches. Silver (Ag) thin films are preferred for developing high-functioning HR windows because of their unique optoelectrical properties. The quality of the HR windows depends on the tradeoff between the transparency and conductivity of the Ag film. Ultrathin Ag (thickness < 10 nm) obtained using the wetting technique has been universally adopted to overcome this trade-off. However, the use of a wetting layer can hinder the optimum transparency of HR windows because of the possible optical loss associated with the wetting layer. Herein, the partial oxidation technique was thoroughly investigated for fabricating one-step grown Ag used for high-functioning HR windows. The incorporation of oxygen (5.7 % volume) during Ag sputtering allowed the direct growth of continuous Ag film on substrates with a percolation threshold below 4 nm. Partial oxidization of Ag resulted in modulated optical coefficients of Ag, thereby facilitating the ease of developing AZO/Ag (6.5 nm)/glass with optimum transparency of 98 % and sheet resistance of 12 Ω sq−1. AZO/Ag/glass possessing a high Haacke figure of merit 68.1 (10−3 Ω−1) was developed for HR windows, with the capability of providing a temperature discrepancy of 2 °C for different simulated weather conditions.

Digital inverse patterning solutions for fabrication of high-fidelity microstructures in spatial light modulator (SLM)-based projection lithography.

Digital mask projection lithography (DMPL) technology is gaining significant attention due to its characteristics of free-mask, flexibility, and low cost. However, when dealing with target layouts featuring sizes smaller than the wavelength scale, accurately producing resist patterns that closely match the target layout using conventional methods to design the modulation coefficients of digital masks produced by spatial light modulators (SLM) becomes challenging. Here, we present digital inversion lithography technology (DILT), which offers what we believe to be a novel approach to reverse engineer the modulation coefficients of digital masks. In the case of binary amplitude modulation, DILT achieves a remarkable reduction in pattern errors (PE), reaching the original 0.26. At the same time, in the case of the gray amplitude modulation, the PE can be reduced to the original 0.05, which greatly improves the high-fidelity transfer of the target layout. This significant improvement enhances the accuracy of target design transfer. By leveraging the capabilities of DILT, DMPL can now attain higher precision and reliability, paving the way for more advanced applications in the field of micro-nano device manufacturing.

On-chip oscillator based temperature-to-digital converter exploiting channel length modulation coefficient λ

This work presents a fully integrated, self-clocked temperature-to-digital converter-based smart temperature sensor for thermal monitoring of SoC for self-heating problem. The design utilizes the channel length modulation coefficient λ with MOSFET sensing followed by a time-to-digital converter (TDC). The proposed method considers the ratio of saturation currents of two nMOSFETs with constant gate voltages but different gate lengths. At a CMOS process of 90-nm and supply voltage of 1.1 V, the sensor occupies a small area of 0.047 mm2. The sensor further attains a resolution of 0.036OC over a temperature range of −40OC to 100OC and limits the inaccuracy between −0.79OC and 0.78OC after two-point calibration.

Metamaterials with modulated coefficient of thermal expansion and ultra-low thermal stress

Mechanical Metamaterials, which integrate multi-material systems, possess the exclusive capability to modulate the coefficient of thermal expansion (CTE). However, the thermal stress induced by the uncoordinated deformation of multi-material seriously restricts their engineering applications under cyclic and extreme temperature variations. Here, an innovative Zigzag Connection (ZC) metamaterial is originally developed to integrate the modulated CTE and ultra-low thermal stress, in contrast to the End-to-end Connection (EC) and Side-to-side Connection (SC) metamaterials reported in the literature. The mechanism and theoretical analysis of the CTE and thermal stress are established and validated through numerical simulations. It is revealed that the EC and SC metamaterials consistently generate the high thermal stress far beyond the yield strength, while the newly designed ZC metamaterial simultaneously exhibits the modulated CTE and ultra-low thermal stress. Moreover, an Ashby plot of CTE versus thermal stress is illustrated, and the concept of temperature variation tolerance is defined to guide the comprehensive design of these metamaterials. The ZC metamaterial shows a higher temperature variation tolerance within compared with the EC and SC metamaterials. Overall, the ZC metamaterial emerges as a solution for the inherent conflict between the modulate CTE and thermal stress, highlighting its obvious superiority of applications under high-temperature environments.