Full Amplitude Research Articles

Quartz as an accurate high-field low-cost THz helicity detector

Emerging concepts employing angular momentum of THz light for ultrafast material control rely on the measurement of undistorted intense THz fields and on the precise knowledge about sophisticated THz helicity states. Here, we establish z-cut α-quartz as a precise electro-optic THz detector for full amplitude, phase, and polarization measurement of highly intense THz fields, all at a fraction of costs of conventional THz detectors. We experimentally determine its detector response function, in excellent agreement with our modeling. Thereupon, we develop a swift and reliable protocol to precisely measure arbitrary THz polarization and helicity states. This two-dimensional electro-optic sampling in α-quartz fosters rapid and cost-efficient THz time-domain ellipsometry and enables the characterization of polarization-tailored fields for driving chiral or other helicity-sensitive quasi-particles and topologies.

Seismic attributes and quantitative inverse dynamical simulations for characterization of late Cretaceous classical fluvial meander channelized stratigraphic traps system, onshore Indus, Pakistan: Implications for hydrocarbon exploration

Meandering channel systems and point bars (PBRL) of the fluvial depositional system (FDPS) globally form primary stratigraphic traps (PST). These ultra-thin-bedded and sub-seismic features are developed during rising sea-levels (transgressive) and standstill (aggradational parasequences) inside the transgressive system tract (TST). The aggradational parasequences of TST have coarse-grained sandstone-filled PSTs, which have specific thickness, density, velocity, angle of the sedimentary reserves, and depositional and erosional characteristics for the development of seismic reflection configurations. All these implications are the key controlling factors for developing the aggrading parasequence sets of TST throughout a sea-level standstill, which is not feasible to predict using the full spectrum-based time and depth mapping tools. The full spectrum-based amplitude volumes lack the tuning frequency content for achieving the above-addressed implications. They require sophisticated tuned-frequency amplitudes, which are responsible to resolve these PSTs when they are filled with porous (Ps) and gas-saturated (Sgas) sedimentary facies, and hence, they show unique seismic-based expressions (velocity and density). Therefore, all these implications are achieved in this study by operating the spectral attributes and the instantaneous spectral decomposition-based velocity and density reservoir simulations (SVDRS) on a hydrocarbons-producing arena, onshore Indus, Pakistan. The tuning thickness for this FDPS was 8.75 m. The 42-Hz spectral attribute shows ∼13 m parallel and wavy seismic reflection configurations, but failed in predicting the horizontally deposited PST, simulated density and velocity, shelf or basin plain, and lateral distribution of Sgas and Ps point bars along the subsidence zones. SVDRS have predicted the ∼86–95% Sgas; ∼31–35% Ps; 14–16 m thick (on inverted density simulation); 2453–2500 m/s velocity; inside the 2.2–2.3 g/c.c densely-fractured and inclined (<3°) aggradational parasequences with parallel reflection configurations for high sinuosity index (S.I) > 2.2 PBRLs, which implicates the presence of a meandering channelized reservoir stream. These stratigraphic configurations implicate the low-risk and highly rewarding hydrocarbon prospecting zones due to no spilling out of the hydrocarbon from the PST during the sea-level standstills. These hydrocarbon-bearing PBRLs have a lateral extent of >2 km, which is an appreciable signature of velocity and densities to develop these traps as the future stratigraphic prospect. These PBRLs with >90% Sgas and >32% Ps of PST are completely embedded within the topmost and horizontal regions with transgressive shales facies (seal) of TST and low-Ps shaly-sandstones, which implicates the landward shifting of shoreline during the sea-level rising events. The uncertainty analysis for simulated velocity and density validates a strong R2>0.85% and 0.90% along the high sinuosity index (S.I.)>2.2 implicates the presence of meandering channel streams., which have implicated the presence of non-Ps and water-statured (Sw) retrogradational parasequences. This workflow has developed this FDPS into a pure stratigraphic trap, and hence, the presented scheme of exploration may serve to explore the remaining reserves from the exploration zones for global FDPS.

Burst c-VEP Based BCI: Optimizing stimulus design for enhanced classification with minimal calibration data and improved user experience

The utilization of aperiodic flickering visual stimuli under the form of code-modulated Visual Evoked Potentials (c-VEP) represents a pivotal advancement in the field of reactive Brain–Computer Interface (rBCI). A major advantage of the c-VEP approach is that the training of the model is independent of the number and complexity of targets, which helps reduce calibration time. Nevertheless, the existing designs of c-VEP stimuli can be further improved in terms of visual user experience but also to achieve a higher signal-to-noise ratio, while shortening the selection time and calibration process. In this study, we introduce an innovative variant of code-VEP, referred to as “Burst c-VEP”. This original approach involves the presentation of short bursts of aperiodic visual flashes at a deliberately slow rate, typically ranging from two to four flashes per second. The rationale behind this design is to leverage the sensitivity of the primary visual cortex to transient changes in low-level stimuli features to reliably elicit distinctive series of visual evoked potentials. In comparison to other types of faster-paced code sequences, burst c-VEP exhibit favorable properties to achieve high bitwise decoding performance using convolutional neural networks (CNN), which yields potential to attain faster selection time with the need for less calibration data. Furthermore, our investigation focuses on reducing the perceptual saliency of c-VEP through the attenuation of visual stimuli contrast and intensity to significantly improve users’ visual comfort. The proposed solutions were tested through an offline 4-classes c-VEP protocol involving 12 participants. Following a factorial design, participants were instructed to focus on c-VEP targets whose pattern (burst and maximum-length sequences) and amplitude (100% or 40% amplitude depth modulations) were manipulated across experimental conditions. Firstly, the full amplitude burst c-VEP sequences exhibited higher accuracy, ranging from 90.5% (with 17.6s of calibration data) to 95.6% (with 52.8s of calibration data), compared to its m-sequence counterpart (71.4% to 85.0%). The mean selection time for both types of codes (1.5 s) compared favorably to reports from previous studies. Secondly, our findings revealed that lowering the intensity of the stimuli only slightly decreased the accuracy of the burst code sequences to 94.2% while leading to substantial improvements in terms of user experience. Taken together, these results demonstrate the high potential of the proposed burst codes to advance reactive BCI both in terms of performance and usability. The collected dataset, along with the proposed CNN architecture implementation, are shared through open-access repositories.

Helicity amplitudes without gauge cancellation for electroweak processes

In the 5-component representation of weak bosons, the first four components make a Lorentz four vector, representing the transverse and longitudinal polarizations excluding the scalar component of the weak bosons, whereas its fifth component corresponds to the Goldstone boson. We obtain the 5×5\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$5\ imes 5$$\\end{document} component propagators of off-shell weak bosons, proposed previously and named after the Goldstone boson equivalence theorem, by starting from the unitary-gauge representation of the tree-level scattering amplitudes, and by applying the BRST (Becchi–Rouet–Stora–Tyutin) identities to the two sub-amplitudes connected by each off-shell weak-boson line. By replacing all weak boson vertices with those among the off-shell 5-component wavefunctions, we arrive at the expression of the electroweak scattering amplitudes, where the magnitude of each Feynman amplitude has the correct on-shell limits for all internal propagators, and hence with no artificial gauge cancellation among diagrams. Although our derivation is limited to the tree-level only, it allows us to study the properties of each Feynman amplitude separately, and then learn how they interfere in the full amplitudes. We implement the 5-component weak boson propagators and their vertices in the numerical helicity amplitude calculation code HELAS (Helicity Amplitude Subroutines), so that an automatic amplitude generation program such as MadGraph can generate the scattering amplitudes without gauge cancellation. We present results for several high-energy scattering processes where subtle gauge-theory cancellation among diagrams takes place in all the other known approaches.

Mechanosensation in leaf veins.

Whether the plant vasculature has the capacity to sense touch is unknown. We developed a quantitative assay to investigate touch-response electrical signals in the leaves and veins of Arabidopsis thaliana. Mechanostimulated electrical signaling in leaves displayed strong diel regulation. Signals of full amplitude could be generated by repeated stimulation at the same site after approximately 90 minutes. However, the signals showed intermediate amplitudes when repeatedly stimulated in shorter timeframes. Using intracellular electrodes, we detected touch-response membrane depolarizations in the phloem. On the basis of this, we mutated multiple Arabidopsis H+-ATPase (AHA) genes expressed in companion cells. We found that aha1 aha3 double mutants attenuated touch-responses, and this was coupled to growth rate reduction. Moreover, propagating membrane depolarizations could be triggered by mechanostimulating the exposed primary vasculature of wild-type plants but not of aha1 aha3 mutants. Primary veins have autonomous mechanosensory properties which depend on P-type proton pumps.

The application of a multidisciplinary methodological approach to the training of physical therapists in the process of rehabilitation of a patient with a gunshot wound to the spinal cord

rehabilitation is one of the key areas of medicine, especially during periods of full-scale war, when militaries and civilians require long-term rehabilitation interventions. The use of a multidisciplinary approach in rehabilitation made it possible to expand the scope and opportunities of rehabilitation treatment and improve the recovery of patients. A physical therapist plays an important role in a multidisciplinary team and carries out rehabilitation measures to eliminate, stop or reduce pain, restore body functions, achieve a normal level of health, physical independence and activity, optimal physical condition and well-being. The training of qualified physical therapists is an important component of successful rehabilitation. The article presents the results of the cooperated work of specialists of the multidisciplinary team of the Military Medical Clinical Treatment and Rehabilitation Center of city Irpin, and physical therapy higher education applicants of the Department of Physical Rehabilitation and Sports Medicine of the Bogomolets National Medical University. The aim of the work was to improve the practical skills of physical therapy higher education applicants by integrating them into the work process of a multidisciplinary rehabilitation team for the rehabilitation of a patient with a gunshot wound to the spinal cord. Higher education applicants took part in the rehabilitation examination and had the opportunity to expand practical skills in this direction. The team of specialists conducted the following rehabilitation tests and obtained results - according to the ASIA scale, the degree of damage to the patient's spinal cord is complete - there is no sensitivity and motor function of the S4-S5 segments, according to the modified Rankin scale 5 points, which corresponds to severe functional disability; according to the Barthel index, 10 points, which corresponds to the patient's complete dependence on external assistance, according to manual muscle testing, the strength of the muscles of the upper shoulder girdle corresponded to 3 points - the full amplitude of movement against the force of gravity. On the basis of the obtained results, the multidisciplinary team determined the main violations according to the domains of the international classification of functioning, and in accordance with them, the higher education applicants developed the key goals of rehabilitation and methods that must be included in the rehabilitation process. Physical therapy higher education applicants conducted rehabilitation interventions aimed at improving patient mobility and self-care, prevention of bedsores, contractures, improvement of the musculoskeletal system, and increased tolerance to physical exertion. After six weeks of the rehabilitation process, repeated rehabilitation examinations were carried out, positive dynamics were admitted according to the Rankin scale, according to the Barthel index and manual muscle testing. The higher education applicants survey showed that while working in a multidisciplinary team, physical therapist higher education applicants managed to expand their knowledge, practical skills and acquire the necessary components for work and close interaction with all team members, to increase the effectiveness of rehabilitation measures for a patient with a spinal cord injury.

Anomalous triple gauge couplings in electroweak dilepton tails at the LHC and interference resurrection

We study the electroweak dilepton production with two forward jets at the LHC, aiming to measure the anomalous triple gauge couplings in the Effective Field Theory (EFT) approach. This process exhibits a distinctive feature, namely, the interference between Standard Model (SM) and beyond the SM is resurrected in the inclusive cross section of the full amplitude, including two forward jets. As a concrete illustration, we perform the detailed analytic and numerical study of the interference using a simpler toy process, and discuss the subtlety of the effective W approximation. We propose a new kinematic variable, VBFhardness, that controls the amount of energy flowing into the dilepton subprocess. We show that an appropriate cut on VBFhardness makes the interference resurrection manifest. Finally, we use the invariant mass of the dilepton system as well as the transverse momentum, as done in the literature, to derive the sensitivity to anomalous triple gauge couplings at the LHC and the high luminosity LHC. Our result is compared with the existing limits from the experiments.

Systematic design method for generation, storage, and reconstruction of holographic images.

Metasurface has extraordinary capability in the wavefront manipulation of electromagnetic waves, which provides an effective method for meta-holographic technology. However, holographic technology mostly focuses on the generation of the single-plane image, which lacks a systematic design method to generate, store, and reconstruct multi-plane holographic images. In this paper, the Pancharatnam-Berry phase meta-atom is designed as electromagnetic controller with the characteristics of the full phase range and high reflection amplitude. Different from the single-plane holography method, a novel multi-plane retrieval algorithm is proposed for the computation of the phase distribution. The metasurface, containing only 24 × 24 (30 × 30) elements, can produce high-quality single-(double-) plane image(s) with fewer elements. Meanwhile, the implementation of the compressed sensing approach stores almost all the holographic image information under a 25% compression ratio and reconstructs the image by the compressed data. The experimental measurements of the samples are consistent with the theoretical and simulated results. This systematic scheme provides an innovative and effective way for designing miniaturized meta-devices to generate high-quality images, which relate to practical applications including high-density data storage, information security, and imaging.

A Compact High-Stability Nanosecond Pulse Test System Using Corona-Stabilized Switch and Coaxial Resistance Divider

Due to the lack of a standard nanosecond high-voltage pulse generator for sensor calibration, a high-stability nanosecond high-voltage pulse test system was developed in terms of circuit analysis, structural design, and performance test. By establishing the equivalent circuit model of the nanosecond pulse generator, the circuit component parameters of the five-stage Marx loop and the one-stage compression steepening unit were simulated. The influence of the action performance of the steepening gap on the characteristics of output nanosecond pulse was analyzed. The nanosecond pulse test system was established through the structural design of the nanosecond pulse-generating circuit, the development of a high-performance corona-stabilized switch, and the measurement of a fast-response resistance divider made of metal oxide thin-film resistors. The nanosecond pulse test system has the capability to output a double exponential nanosecond pulse voltages in the amplitude range of 10–60 kV with a rise time of 2.3 ± 0.5 ns and a half-peak time of 23 ± 5 ns. In addition, the output pulse voltage has a high consistency and stability in the full amplitude range. The maximum relative standard deviation of the peak value is 1.517%, and the relative standard uncertainty is less than 5‰.

90-m/560-Mbps underwater wireless optical communication utilizing subband multiple-mode full permutation CAP combined with an SNR-weighted detector and multi-channel DFE.

In this paper, a joint signal processing scheme including a subband multiple-mode full permutation carrierless amplitude phase modulation (SMMP-CAP), signal-to-noise ratio weighted detector (SNR-WD), and multi-channel decision feedback equalizer (MC-DFE) is proposed to mitigate the bandwidth limitation of a high-speed long-reach underwater wireless optical communication (UWOC) system. Referring to the trellis coded modulation (TCM) subset division strategy, 16 quadrature amplitude modulation (QAM) mapping set is divided into four 4-QAM mapping subsets by SMMP-CAP scheme. An SNR-WD and an MC-DFE are employed to enhance the demodulation effect of this system in a fading channel. In a laboratory experiment, the minimal required received optical powers (ROPs) for data rates of 480 Mbps, 600 Mbps, and 720 Mbps, at hard-decision forward error correction (HD-FEC) threshold of 3.80 × 10-3, are -32.7 dBm, -31.3 dBm, and -25.5 dBm, respectively. Moreover, the proposed system successfully achieves a data rate of 560 Mbps in a swimming pool with a transmission distance up to 90 m and a total attenuation measured to be 54.64 dB. To the best of our knowledge, this is the first time to demonstrate a high-speed, long-distance UWOC system by employing an SMMP-CAP scheme.

Multifocus Multinull Near-Field Transmitting Focused Metasurface

We propose a novel design of a near-field transmitting focused metasurface, which transforms a linearly polarized planar incident wave into a near-field focused beam with multiple foci and multiple nulls in this article. A generalized method of obtaining the metasurface field distribution on its aperture for specified near-field foci and nulls is first introduced. Then, a three-layer metasurface particle structure with close to full range reconfigurable amplitude and phase transmitting response for realizing the required field distribution is studied. By adjusting the arc length and the rotating angle of the middle-layer metasurface particle structure, a transmitting response with arbitrary amplitude and phase is achieved. Finally, a focused metasurface with two near-field foci and two near-field nulls is designed based on the proposed theory and metasurface particle structure. The designed metasurface is full-wave simulated, fabricated, and measured in the experiment. The experimental results agree well with the full-wave simulating results, showing that both the foci and nulls are well presented at the specified positions and the measured power of the near-field nulls is more than 26 dB below the power of the foci.

Phenomenological model for the γγ→π+π−π0 reaction

We present a phenomenological model for the $\gamma\gamma \to \pi^+\pi^-\pi^0$ reaction by including the production mechanism of the $a_2(1320)$ resonance, as well as the contributions from the $\sigma/f_0(500)\, \pi^0$ and $f_2(1270)\, \pi^0 $ production channels. Furthermore, the $\gamma\gamma\to\rho^{\pm} \pi^{\mp}\to\pi^{+}\pi^-\pi^0$ channel, which is essential for a description in the low-energy region, is investigated carefully by introducing the complete set of gauge invariant and Lorentz-covariant tensors for the $\gamma\gamma\to\rho^\pm \pi^\mp$ subprocess. The full amplitude is constructed to yield a correct high-energy Regge behavior. Within our model, we achieve a very reasonable description of ARGUS and L3 data of the total cross section, as well as of the $\pi^\pm\pi^0$ and $\pi^+\pi^-$ invariant mass distributions. We also predict the invariant mass distributions in the $\gamma\gamma$ center-of-mass energy range from $0.8$ GeV to $2.0$ GeV, which will be studied by the forthcoming data of the BESIII collaboration.

The path from the Chinese and Japanese observations of supernova 1181 AD, to a Type Iax supernova, to the merger of CO and ONe white dwarfs

ABSTRACT In 1181 ad, Chinese and Japanese observers reported an unmoving bright ‘Guest Star’ in the constellation Chuanshe, visible for 185 d. In 2013, D. Patchick discovered what turned out to be a unique nebula surrounding a unique star, with the structure named ‘Pa 30’, while subsequent workers made connections to mergers of white dwarfs, to the supernova subclass of low-luminosity Type Iax, and to the 1181 transient. Here, I provide a wide range of new observational pieces of evidence: First, detailed analysis of the original Chinese and Japanese reports places the ‘Guest Star’ of 1181 into a small region with the only interesting source being Pa 30. Second, the ancient records confidently place the peak magnitude as 0.0 &amp;gt; Vpeak &amp;gt; −1.4, and hence peak absolute magnitude −14.5 &amp;gt;MV, peak&amp;gt;−16.0 mag. Third, the Pa 30 central star is fading from B = 14.9 in 1889, to B = 16.20 in 1950, to B = 16.58 in 2022. Fourth, recent light curves show typical variability with full amplitude of 0.24 mag on time-scales of 1 d and longer, critically with no coherent modulations for periods from 0.00046–10 d to strict limits. Fifth, the spectral energy distribution from the far-infrared to the ultraviolet is a nearly perfect power law with Fν ∝ ν0.99 ± 0.07, observed luminosity 128 ± 24 L⊙, and absolute magnitude MV = +1.07. I collect my new pieces of evidence with literature results to make a confident case to connect the East-Asian observations to a supernova, then to Pa 30, then to a low-luminosity Type Iax SN, then to the only possible explosion mechanism as a merger between CO and ONe white dwarfs.

A Single-Shot Harmonic Imaging Approach Utilizing Deep Learning for Medical Ultrasound.

Tissue Harmonic Imaging (THI) is an invaluable tool in clinical ultrasound owing to its enhanced contrast resolution and reduced reverberation clutter in comparison to fundamental mode imaging. However, harmonic content separation based on high pass filtering suffers from potential contrast degradation or lower axial resolution due to spectral leakage. Whereas nonlinear multi-pulse harmonic imaging schemes, such as amplitude modulation and pulse inversion, suffer from a reduced framerate and comparatively higher motion artifacts due to the necessity of at least two pulse echo acquisitions. To address this problem, we propose a deep-learning-based single-shot harmonic imaging technique capable of generating comparable image quality to pulse amplitude modulation methods, yet at a higher framerate and with fewer motion artifacts. Specifically, an asymmetric convolutional encoder-decoder structure is designed to estimate the combination of the echoes resulting from the half-amplitude transmissions using the echo produced from the full amplitude transmission as input. The echoes were acquired with the checkerboard amplitude modulation technique for training. The model was evaluated across various targets and samples to illustrate generalizability as well as the possibility and impact of transfer learning. Furthermore, for possible interpretability of the network, we investigate if the latent space of the encoder holds information on the nonlinearity parameter of the medium. We demonstrate the ability of the proposed approach to generate harmonic images with a single firing that are comparable to those from a multi-pulse acquisition.

Revealing the embedded phase in single-pixel quantum ghost imaging

Single-pixel quantum ghost imaging involves the exploitation of non-local photon spatial correlations to image objects with light that has not interacted with them and, using intelligent spatial scanning with projective masks, reduces detection to a single pixel. Despite many applications, extension to complex amplitude objects remains challenging. Here, we reveal that the necessary interference for phase retrieval is naturally embedded in the correlation measurements formed from traditional projective masks in bi-photon quantum ghost imaging. Using this, we develop a simple approach to obtain the full phase and amplitude information of complex objects. We demonstrate straightforward reconstruction without ambiguity using objects exhibiting spatially varying structures from phase steps to gradients as well as complex amplitudes. This technique could be an important step toward imaging the phase of light-sensitive structures in biological matter.

Spin-foams as semiclassical vertices: Gluing constraints and a hybrid algorithm

Numerical methods in spin-foam models have significantly advanced in the last few years, yet challenges remain in efficiently extracting results for amplitudes with many quantum degrees of freedom. In this paper we sketch a proposal for a ``hybrid algorithm'' that would use both the full quantum amplitude and its asymptotic approximation in the relevant regimes. As a first step towards the algorithm, we derive a new representation of the partition function where each spin-foam vertex possesses its own coherent data, such that it can be individually asymptotically approximated. We do this through the implementation of gluing constraints between vertices, which we study numerically. We further derive an asymptotic expression for the constraints for arbitrary boundary data, including data for which there are no critical points. From this new representation we conjecture an intermediate quasi-geometric spin-foam regime describing a superposition of semi-classical vertices glued in a non-matching way via the gluing constraints.

Design of metasurfaces with decoupled amplitude and phase response for spatial light modulation.

Spatial light modulators based on metasurfaces have attracted great attention due to their abilities of amplitude and phase modulation. However, the traditional one degree of freedom (1-DOF) tunable metasurfaces are limited by incomplete phase coverage and coupled amplitude and phase modulation. Here, we propose an optimization method for 2-DOF tunable metasurfaces within the framework of temporal coupled mode theory. As a validation of the proposed method, we present a germanium antimony tellurium (GST)-alloy-based 2-DOF tunable reflective metasurface. Full-wave simulation shows that independent modulation of amplitude and phase is realized with full phase coverage and amplitude range from 0 to 0.55. Our proposed design scheme for a 2-DOF tunable metasurface may facilitate the development of high-performance metasurface devices.

High-Speed Shift Register with Dual-Gated Thin-Film Transistors for a 31-Inch 4K AMOLED Display.

In this work, a promising dual-gated thin film transistor (TFT) structure has been proposed and introduced in the shift register (SR)-integrated circuits to reduce the rising time. The threshold voltage can be simultaneously changed by the top gate and the bottom gate in the proposed dual-gated TFTs. When the SR circuits start to export the scan signals in the displays, the driving currents in the SR circuits are increased by switching the working station of driving TFTs from the enhancement characterization to the depletion characterization. Subsequently, the detailed smart spice simulation has been used to study the function of the proposed SR circuits. In the next step, the proposed SR circuits have been fabricated in a G4.5 active-matrix organic light-emitting diode manufacture factory. The simulated and experimental results indicate that the shift register pulses with the full swing amplitude can be obtained in the SR circuits. Moreover, in contrast to the conventional SR circuits employing with the single-gated TFTs, it has been found that the rising time of the output signals can be reduced from 3.75 μs to 1.23 μs in the proposed SR circuits with the dual-gated TFTs, thus exhibiting the significant improvement of the driving force in the proposed SR circuits. Finally, we demonstrated a 31-inch 4K AMOLED display with the proposed SR circuits.

On the positivity of Coon amplitude in D = 4

The Coon amplitude is the unique solution to duality constraints with logarithmic Regge trajectories. A striking feature of this solution is that it interpolates between the Veneziano amplitude and a scalar particle amplitude. However, an analytic proof of unitarity of the amplitude is not yet known. In this short note, we explicitly compute the partial wave coefficients on the leading Regge trajectory in D = 4. We find that these coefficients always remain positive, even though their magnitude decreases with spin. Since the coefficients on the subleading trajectories are observed to be larger than those on the leading ones, our result indicates the positivity of the full Coon amplitude in D = 4.

K-Band Digital Power Amplifier Based on InP DHBT

Based on 0.7-μm indium phosphide (InP) double heterojunction bipolar transistor (DHBT) process, this paper designs a digital power amplifier (DPA) monolithic microwave integrated circuit. Digital-to-analog converter (DAC), modulation and power amplifier are integrated into the DPA, reducing losses and improving linearity of traditional radio frequency (RF) links. The test results show that the DPA can achieve an output power of 23-23.5 dBm and power added efficiency (PAE) of 21.5-23% within 19.2-21.2 GHz. And the mean squared error of normalized output voltage is 0.0158 at 20 GHz. Then, asymmetrical synthesis technology is used to improve the efficiency of DPA in non-full amplitude state. Simulation results of DPA demonstrate saturated output power of 23.5 dBm and the maximum PAE of 21.9% in 19-21 GHz. At 20 GHz, the PAE between full and half amplitude state is greater than 20%.