Measuring the Hubble Constant Using Strongly Lensed Gravitational Wave Signals

The measurement of the Hubble constant $H_0$ plays an important role in the study of cosmology. In this letter, we propose a new method to constrain the Hubble constant using the strongly lensed gravitational wave (GW) signals. By reparameterizing the waveform, we find that the lensed waveform is sensitive to the $H_0$. Assuming the scenario that no electromagnetic counterpart of the GW source can be identified, our method can still give meaningful constraints on the $H_0$ with the information of the lens redshift. We then apply Fisher information matrix and Markov Chain Monte Carlo to evaluate the potential of this method. For the space-based GW detector, TianQin, the $H_0$ can be constrained within a relative error of $\sim$ 0.3-2\%, using a single strongly lensed GW event. Precision varies according to different levels of electromagnetic information.Comment: 8 pages, 4 figure

An Opacity-Free Method of Testing the Cosmic Distance Duality Relation Using Strongly Lensed Gravitational Wave Signals

The cosmic distance duality relation (CDDR), expressed as DL(z) = (1 + z)2DA(z), plays an important role in modern cosmology. In this paper, we propose a new method of testing CDDR using strongly lensed gravitational wave (SLGW) signals. Under the geometric optics approximation, we calculate the gravitational lens effects of two lens models, the point mass and singular isothermal sphere. We use functions of {\eta}1(z) = 1 + {\eta}0z and {\eta}2(z) = 1 + {\eta}0z=(1 + z) to parameterize the deviation of CDDR. By reparameterizing the SLGW waveform with CDDR and the distance-redshift relation, we include the deviation parameters {\eta}0 of CDDR as waveform parameters. We evaluate the ability of this method by calculating the parameter estimation of simulated SLGW signals from massive binary black holes. We apply the Fisher information matrix and Markov Chain Monte Carlo methods to calculate parameter estimation. We find that with only one SLGW signal, the measurement precision of {\eta}0 can reach a considerable level of 0.5-1.3% for {\eta}1(z) and 1.1-2.6% for {\eta}2(z), depending on the lens model and parameters.Comment: 15 pages, 7 figure

Authenticity identification method for calligraphy regular script based on improved YOLOv7 algorithm

A regular calligraphy script of each calligrapher has unique strokes, and a script’s authenticity can be identified by comparing them. Hence, this study introduces a method for identifying the authenticity of regular script calligraphy works based on the improved YOLOv7 algorithm. The proposed method evaluates the authenticity of calligraphy works by detecting and comparing the number of single-character features in each regular script calligraphy work. Specifically, first, we collected regular script calligraphy works from a well-known domestic calligrapher and divided each work into a single-character dataset. Then, we introduced the PConv module in FasterNet, the DyHead dynamic detection header network, and the MPDiou bounding box loss function to optimize the accuracy of the YOLOv7 algorithm. Thus, we constructed an improved algorithm named YOLOv7-PDM, which is used for regular script calligraphy identification. The proposed YOLOv7-PDM model was trained and tested using a prepared regular script single-character dataset. Through experimental results, we confirmed the practicality and feasibility of the proposed method and demonstrated that the YOLOv7-PDM algorithm model achieves 94.19% accuracy (mAP50) in detecting regular script font features, with a single-image detection time of 3.1 m and 31.67M parameters. The improved YOLOv7 algorithm model offers greater advantages in detection speed, accuracy, and model complexity compared to current mainstream detection algorithms. This demonstrates that the developed approach effectively extracts stroke features of regular script calligraphy and provides guidance for future studies on authenticity identification

Multiple “hits” during postnatal and early adulthood periods disrupt the normal development of sensorimotor gating ability in rats

In the present study, we evaluated a multiple-hit animal model of schizophrenia in an attempt to capture the complex interactions among various adverse developmental factors in schizophrenia. Sprague–Dawley rats were assigned to receive either repeated daily 3-h maternal separation for eight days (first “hit”) on postnatal days (PND) 3 to 10, and/or avoidance conditioning for six days (second “hit”) on PND 49–56, and/or repeated phencyclidine treatment (third “hit”, 3.0 mg/kg, sc) immediately after each daily avoidance conditioning. Prepulse inhibition (PPI) of acoustic startle reflex was assessed at late adolescence (PND 41–43) and early adulthood (PND 62–63). The change in %PPI from the adolescence phase to adulthood phase was used to index the maturation-related improvement of sensorimotor gating ability. Maternal separation, avoidance conditioning, and PCP treatment had a complex three-way interaction on the functional improvement of sensorimotor gating. Maternal separation impaired PPI improvement preferentially in the saline rats that were not subjected to avoidance conditioning. Avoidance conditioning had no effect on PPI improvement in the non-maternally separated rats, but restored the maternal separation-induced disruption. However, this restoration effect was abolished by PCP treatment. The present study also identified a number of behavioral, emotional and learning abnormalities caused by these three developmental insults which may precede their interactive disruption of normal development of sensorimotor gating ability

Development of 5 kW single-phase non-isolated inverter

Aiming at the weaker suppression ability of grid-connected inverters with traditional PI and proportional resonance PR control, a single-phase grid-connected inverter control scheme based on quasi-PR control strategy is proposed. A small-scale, low-cost single-phase non-isolated 5 kW inverter that can be used for large-scale power supply at home has been simulated and connected to the grid. The design principle of the inverter is expounded from two aspects of hardware and software. The simulation analysis is carried out by using the S-Function function in Matlab software. The control strategy is based on quasi-PR control and compared with the traditional PI and PR controllers. Based on the simulation, the experimental verification is carried out with an experimental prototype. The research results show that the proposed quasi-PR control strategy has great advantages compared with PI and PR control in eliminating steady-state error, improving grid-side current quality and resisting grid interference. Not only can it be better to achieve no static control, but also has scalability. With the static-free characteristics of the quasi-PR controller, the single-phase non-isolated 5 kW inverter will have broad application prospects in the home power supply system

High-efficiency separation of CO2 from CO2-CH4 gas mixtures via gas hydrates under static conditions

Hydrate technology with high gas storage capacity and excellent safety features has attracted much attention for capturing CO2 from biogas to produce purified CH4. When considering operational efficiency, it is desirable to overcome technical barriers such as slow hydrate generation and low separation efficiency. Therefore, based on the properties of surfactant-enhanced hydrate generation kinetics, this work first systematically evaluated the performance of 500 ppm SDS on the separation efficiency of 40 mol% CO2 and 60 mol% CH4 simulated biogas. The experimental results show a significant increase in gas capture at higher driving forces, with the rise being dominated by the CH4 component, indicating that larger driving forces reduce hydrate selectivity to CO2-CH4 and weaken gas separation efficiency, with a maximum CO2 recovery of 84.24 +/- 1.19% at 275.15 K and 8 MPa. Interestingly, hydrate growth mainly occurred in the liquid phase, leading to the separation factor being positively correlated with the induction time with sufficient CO2 dissolution. In comparison, the gas capture per unit volume of solution could be improved by more than a factor of 2 at higher gas-liquid ratios. The best separation factor of 7.84 +/- 0.73 was achieved, and separation factors in general gradually decreased with increasing gas-liquid ratio; however, there was high-pressure failure behavior. Furthermore, the impact of the defoamer on separation efficiency was deeply investigated for SDS decomposition foaming, with results showing that the defoamer would alleviate hydrate decomposition foaming behaviour while having no significant effect on hydrate generation kinetics and separation efficiency