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This paper investigates possibilities of deriving new digital-to-analog converter (DAC) architectures based on polygonal and prime number theories. As the result, configurations of polygonal number DACs and prime number DACs are obtained; each consists of a few current sources, a resistor network, switch arrays and a decoder circuit. Whole circuits are designed and their operations are confirmed with simulation; they work as DAC in principle. In many cases, analog/mixed-signal circuit architecture design relies on intuitions and experiences of the designer, but here we demonstrate that it is feasible to derive different DAC architectures from conventional ones based on mathematical theory.

We study the twisted control of the near-field radiative heat transfer between two hyperbolic antiferromagnetic insulators under external magnetic fields. We show that the near-field heat flux can be affected by both the twist angle $\theta$ and the magnitude of the applied magnetic field with different broken symmetries. Irrespective of twist angle, the external magnetic field causes the radiative heat flux to change nonmonotonically, and the minimum heat flux can be found with the magnetic fields of about 1.5 T. Such nonmonotonic behavior is due to the fact that the magnetic field can radically change the nature of the magnon polaritons with time reversal symmetry breaking. The field not only affects the topological structure of surface magnon polaritons, but also induces the volume magnon polaritons that progressively dominate the heat transfer as the field increases. We further propose a twist-induced thermal switch device with inversion symmetry breaking, which can severely regulate radiative heat flux through different magnetic fields. Our findings account for a characteristic modulation of radiative heat transfer with implications for applications in dynamic thermal management.

This paper describes new configurations of digital-to-analog converters (DACs) based on number theory: (i) DACs consisting of N current sources, N-angle number weighted resistor networks, switch arrays and decoders (N= 3, 4, 5,…). (ii) A DAC composed of two current sources, a prime number weighted resistor network, switch array, a decoder; this is based on Goldbach's conjecture in the number theory. Their principles, configurations and operations are presented.

RNAs play crucial and versatile roles in biological processes. Computational prediction approaches can help to understand RNA structures and their stabilizing factors, thus providing information on their functions, and facilitating the design of new RNAs. Machine learning (ML) techniques have made tremendous progress in many fields in the past few years. Although their usage in protein-related fields has a long history, the use of ML methods in predicting RNA tertiary structures is new and rare. Here, we review the recent advances of using ML methods on RNA structure predictions and discuss the advantages and limitation, the difficulties and potentials of these approaches when applied in the field., Comment: 20 pages, 2 figures. Chinese Physics B, Aug. 2020

This paper investigates multi-tone signals for short-time and high quality testing of analog circuit frequency response. First, we study three multi-tone signal generation algorithms for minimum crest factor using an arbitrary waveform generator, and show that they are comparable. Then we propose crest factor controlled multi-tone signal generation algorithms for effective testing of transmitters. These algorithms are verified with simulations.

This paper reviews the authors’ group research results of data-weighted averaging (DWA) algorithm for multi-bit ΔΣADC/DAC/TDC and also dithering techniques for ΔΣ ADC/DAC for limit cycle reduction. When a multi-bit internal DAC or digital-to-time converter (DTC) is used inside a modulator, nonlinearities of the DAC/DTC are not noise-shaped and the SNR of the ΔΣADC/DAC/TDC degrades. To overcome this problem, we investigate several algorithms to noise-shape the DAC/DTC nonlinearities. Also we investigate limit cycle suppression techniques in ΔΣDAC. Then we discuss their generalization.