Search

Quantum error correction technology is an important method to eliminate errors during the operation of quantum computers. In order to solve the problem of the influence of errors on physical qubits, this paper proposes an approximate error correction scheme that performs dimension mapping operations on surface codes. This error correction scheme utilizes the topological properties of error correction codes to map the surface code dimension to three dimensions. Compared to previous error correction schemes, the three-dimensional surface code exhibits good scalability due to its higher redundancy and more efficient error correction capabilities. By reducing the number of ancilla qubits required for error correction, this approach achieves savings in measurement space and reduces resource consumption costs. In order to improve the decoding efficiency and solve the problem of the correlation between the surface code stabilizer and the 3D space after dimension mapping, we employ a Reinforcement Learning (RL) decoder based on Deep Qlearning, which enables faster identification of the optimal syndrome and achieves better thresholds through conditional optimization. Compared to the Minimum Weight Perfect Matching (MWPM) decoding, the threshold of the RL trained model reaches 0.78%, which is 56% higher and enables large-scale fault-tolerant quantum computation.

Digital channelization decomposes a wideband signal into multiple adjacent sub-bands using Parallel Technology. Channelization can effectively reduce the pressure on the radio astronomy digital backends system and make wideband signal processing possible. Aiming at the problems of signal attenuation at sub-band edge, spectral leakage and aliasing encountered in wideband signal channelization, algorithms to reduce the problems are studied. We design a Critically Sampled Polyphase Filter Bank (CS-PFB) based on the Finite Impulse Response (FIR) digital filter with a Hamming Window and systematically analyse the frequency response characteristics of the CS-PFB. Based on the channelized structure of the CS-PFB, an oversampled polyphase filter bank (OS-PFB) is designed by data reuse, and the filtering frequency response characteristics of CS-PFB and OS-PFB are compared and analyzed. Using the wideband baseband data generated by the CASPSR backends of Parkes, we implement sub-band division and 16-band output of these data based on the 2× oversampling OS-PFB, and the problem of spectrum inversion in the sub-bands is corrected. After removing 25% of redundant data in the head and tail of each sub-band, we recombine the sub-bands into a wideband. The wideband signal is almost identical to the original observed signal. Therefore, the experimental results show that OS-PFB can eliminate signal attenuation at the sub-band edge, spectrum leakage and aliasing caused by channelization. For the 400MHz baseband data of J0437-4715, we compare the pulse profile obtained from the original baseband data with the pulse profile obtained after the channelization and recombination. The phase and amplitude information of the pulse profiles are consistent, which verifies the correctness of our channelization algorithm.

We study the nonlinear collective dynamics of quasi-one-dimensional spin-orbit coupled spin-1 Bose-Einstein condensates trapped in harmonic potential analytically and numerically. The ground state of the system is determined by minimizing the Lagrange density, and the coupled equations of motions for the center-of-mass coordinate of the condensate and its width are derived. Then, two low energy excitation modes in breathing dynamics and dipole dynamics are obtained analytically, and the mechanism of exciting the anharmonic collective dynamics is revealed explicitly. The coupling among SO coupling, Raman coupling and spin-dependent interaction results in multiple external collective modes, which leads to the anharmonic collective dynamics. The cooperative effect of spin momentum locking and spin-dependent interaction results in coupling of dipolar and breathing dynamics, which strongly depends on spin-dependent interaction and behaves distinct characters in different phases. Interestingly, in absence of spin-dependent interaction, the breathing dynamics is decoupled from spin dynamics and the breathing dynamics is harmonic. Our results provide theoretical evidence for deep understanding the ground sate phase transition and nonlinear collective dynamics of the system.

We report comprehensive transport, electron microscopy and Raman spectroscopy studies on the transition-metal chalcogenides Cu1.89Te single crystals. The metallic Cu1.89Te displays successive metal-semiconductor transitions at low temperatures and almost ideal linear MR when magnetic field up to 33T. Through the electron diffraction patterns, the stable room temperature phase is identified as a 3×3×2 modulated superstructure based on Nowotny hexagonal structure. The superlattice spots of Transmission electron microscopy and Scanning tunneling microscopy clearly show the structural transitions from the room temperature Commensurate Ⅰ (C-Ⅰ) phase to the low temperature Commensurate Ⅱ (C-Ⅱ) phase. All the results can be understood in term of charge density wave (CDW) instability, yielding intuitive evidences for the CDW formations in Cu1.89Te. The additional Raman modes below room temperature further reveal that the zone-folded phonon modes may play an important role on the CDW transitions. Our research sheds light on the novel electron features of Cu1.89Te at low temperature, and may provide potential applications for future nano-devices.

This article has been withdrawn by IOP Publishing following an admission by the authors that this article may contain research errors. IOP Publishing has investigated in line with the COPE guidelines with the help of an independent subject expert, who has found the article contains numerous flaws, which bring into question the reliability of the work presented. As such, IOP Publishing agree that this work should be withdrawn.

Safety is an important factor restricting the cascade utilization of lithium-ion batteries (LIBs). In this paper, the safety characteristics of fresh and retired lithium iron phosphate batteries are investigated by means of a heating-triggered thermal runaway (TR). The results show that under the heating condition of 200 W, the internal short circuit (ISC) can directly cause the TR of a new battery and lead to an explosion with an overpressure of 98.9 kPa. However, there is still a buffer time of 13.1-22.3 min between the ISC and TR for the retired battery with states of health (SOHs) of 80% - 60%, and the retired battery cannot explode. The large-scale ISC onset time, TR onset time, and TR onset temperature of the 70% SOH battery are 27.4 min, 40.5 min, and 179.9 °C, respectively, which are the smallest among retired batteries, indicating that the 70% SOH battery may be more likely to trigger TR. The findings can provide guidance for the safe application of retired batteries.

In order to solve the problem that the medium cannot be supplied accurately during the perfusion culture of the vascular network in large-volume 3D printing tissue, a perfusion control technology was studied by designing and building an in vitro perfusion and monitoring platform with feedback regulation. First, a large-volume vascular network of hydrogel material was fabricated by 3D bioprinting technology as the experimental object of perfusion. Then we designed and built the dynamic perfusion device and the monitoring equipment in the perfusion process independently and applied the real-time flow calibration control technology on this basis. Finally, the accuracy of the flow real-time calibration control technology was verified through the perfusion experiment of the large-volume vascular network. The results showed that the error rate between the actual flow rate and the preset flow rate increased gradually with the decrease of the preset flow rate of medium perfusion. When the preset flow is 3 mL/min, the error rate between them is as high as 19.33% without the application of flow calibration control technology. The dynamic perfusion device can reduce the average error rate between the two from 8.1% to 0.4% after applying real-time flow calibration control technology, which proves that the device can cultivate a large-volume vascular network with high-precision perfusion after the application of real-time flow calibration control technology.

Without the difficulty of applying particular excitations on arch dams, a method using the correlation coefficients of time-scale representations (CCTSRs) of seismic responses to identify the damage in transverse joints is proposed. The identification of damage using the CCTSR method is characterized by comparing the time-scale representations (TSRs) of paired seismic accelerations measured from two neighboring points crossing the transverse joints horizontally. With the CCTSR method, the TSRs of measured seismic accelerations are produced with the continuous wavelet transform; the comparison of the TSRs is carried out by calculating the correlation coefficients. The correlation coefficients of the paired TSRs are combined with the defined damage intervals to evaluate the positions and severities of the damage. The method’s feasibility is numerically verified via the identification of the damage in transverse joints by discussing the effects of the wavelet functions, seismic excitations, and noise resistance. The method’s effectiveness is experimentally validated via the detection of the damage in transverse joints of a scaled arch dam model subjected to artificial seismic loads. The proposed CCTSR method can localize the positions of various damage scenarios and quantify the damage severities caused by progressive seismic loads.

With the rapid development of atom interferometry, atom interferometers have been widely used in inertial navigation, resource exploration, basic physics and other fields. For precise measurement experiments with multi-loop atom interferometer configuration, it is urgent to establish a high-precision theoretical model charactering the relationship between target measurement quantities and measurement results. Based on this, we adopt the idea of co-moving reference frame, so as to transfer the gravity, gravity gradient and Earth’s rotation effects to the laser light field interacting with atoms by translating, rotating and stretching the background spacetime. With this method, we not only can simplify the analysis process of the experimental principle, but also give the analytical results of the high-order interference phase of the multi-loop atom interferometer containing the gravity gradient and Earth’s rotation. This work will lay a certain theoretical foundation for higher-precision experiment, and will also help to clearly guide the implementation of the experiment.

Mimicking the multilayered structure of blood vessels and constructing a porous inner surface are two effective approaches to achieve mechanical matching and rapid endothelialization to reduce occlusion in small-diameter vascular grafts. However, the fabrication processes are complex and time consuming, thus complicating the fabrication of personalized vascular grafts. A simple and versatile strategy is proposed to prepare the skeleton of vascular grafts by rolling self-adhesive polymer films. These polymer films are directly fabricated by dropping a polymer solution on a water surface. For the tubes, the length and wall thickness are controlled by the rolling number and position of each film, whereas the structure and properties are tailored by regulating the solution composition. Double-layer vascular grafts (DLVGs) with microporous inner layers and impermeable outer layers are constructed; a microporous layer is formed by introducing a hydrophilic polymer into a polyurethane (PU) solution. DLVGs exhibit a J-shaped stress–strain deformation profile and compliance comparable to that of coronary arteries, sufficient suture retention strength and burst pressure, suitable hemocompatibility, significant adhesion, and proliferation of human umbilical vein endothelial cells. Freshly prepared PU tubes exhibit good cytocompatibility. Thus, this strategy demonstrates potential for rapid construction of small-diameter vascular grafts for individual customization.

To solve the problem of an unbalanced state of charge (SOC) between the in-phase sub-modules of the cascaded H-bridge energy storage system, this paper proposed a method based on carrier phase-shifting pulse-width modulation. Different from the traditional in-phase balancing method which is achieved by adding components, by setting the parameter related to the SOC difference to adjust the amplitude of the modulation wave, the new method could solve the problem that the traditional method is not applicable under extreme SOC conditions. The new in-phase SOC balancing method could expand the scenario, and the feasibility of the method is verified by simulation.

In order to ensure the stability and reliability of the assembly performance of the solar array driving mechanism, research on the influence of assembly and adjustment coaxiality of harmonic reducer to transmission efficiency of solar array driving mechanism was carried out. With the research, the assembly and adjustment coaxiality mode of the harmonic reducer was analyzed. The driving mechanism simulator and harmonic reducer test piece were developed. Based on a piece of special test equipment, a fully systematic test was carried out. According to the characteristics of different products, the assembly and adjustment coaxiality parameters of harmonic reducer can be accurately and reasonably formulated. The best transmission efficiency of the solar array driving mechanism has been achieved. The on-orbit stable operation of the solar array was effectively ensured.

The energy transition is one of the main challenges of our society and therefore a major driver for the scientific community. To ensure a smart transition to a sustainable future energy scenario different technologies such as energy harvesting using solar cells or windmills and chemical storage in batteries, super-capacitors or hydrogen have to be developed and ultimately deployed. New fabrication approaches based on additive manufacturing and the digitalization of the industrial processes increase the potential to achieve highly efficient and smart technologies required to increase the competitiveness of clean energy technologies against fossil fuels. In this frame, the present roadmap highlights the tremendous potential of 3D printing as a new route to fully automate the manufacturing of energy devices designed as digital files. This article gives numerous guidelines to maximize the performance and efficiency of the next generation of 3D printed devices for the energy transition while reducing the waste of critical raw materials. In particular, the paper is focused on the current status, present challenges and the expected and required advances of 3D printing for the fabrication of the most relevant energy technologies such as fuel cells and electrolysers, batteries, solar cells, super-capacitors, thermoelectric generators, chemical reactors and turbomachinery.

Augmented reality (AR) surgical navigation has developed rapidly in recent years. This paper reviews and analyzes the visualization, registration, and tracking techniques used in AR surgical navigation systems, as well as the application of these AR systems in different surgical fields. The types of AR visualization are divided into two categories of in situ visualization and non in situ visualization. The rendering contents of AR visualization are various. The registration methods include manual registration, point-based registration, surface registration, marker-based registration, and calibration-based registration. The tracking methods consist of self-localization, tracking with integrated cameras, external tracking, and hybrid tracking. Moreover, we describe the applications of AR in surgical fields. However, most AR applications were evaluated through model experiments and animal experiments, and there are relatively few clinical experiments, indicating that the current AR navigation methods are still in the early stage of development. Finally, we summarize the contributions and challenges of AR in the surgical fields, as well as the future development trend. Despite the fact that AR-guided surgery has not yet reached clinical maturity, we believe that if the current development trend continues, it will soon reveal its clinical utility.

A telecommunication network used for the transmission of astronomical observation data, telescope remote control and other astronomical research purposes is a critical infrastructure. The monitoring and analysis of network traffic, which help improve the network performance and the utilization of network resources, are a challenging task. The accurate identification of the astronomical data traffic will effectively improve transmission efficiency. In this paper, a classification method applied to types of traffic containing astronomical data using deep learning is proposed. The advantages of a convolutional neural network model in image classification are exploited to classify types of traffic containing astronomical data. The objective is to identify the mixed traffic in the network and accurately identify types of traffic containing astronomical data. The effectiveness of the model in improving classification accuracy is also discussed. Actual traffic data captured by Tcpdump and Wireshark are tested, and the experimental results indicate that the proposed method can accurately classify types of traffic containing astronomical data.

In order to reduce the prediction error of Air Quality Index (AQI) by Extreme Learning Machine (ELM), an Intelligent Composite Prediction Model (ICPM) is proposed. ICPM uses an Improved Whale Optimization Algorithm (IWOA) to find the ELM parameters. IWOA introduces logarithmically varying nonlinear control factors and cosine varying adaptive weighting factors to balance local exploitation with global search capabilities. Prediction of AQI combined with daily historical data of air quality in Henan Province (2019), it is proved that ICPM has better prediction performance and generalization performance than ELM and other models.

At present, there are few methods for quantitative calculation of installed load or new energy for distribution network equipment. Based on this, this paper proposes a calculation method for the open capacity of the distribution network. Firstly, the calculation methods of the open capacity of a 10 kV distribution transformer, 10 kV lines, and high-voltage substation three-level distribution network based on the conventional situation and new power system are studied, respectively. Then the calculation methods of the open capacity of the distribution system based on the conventional case and the new power system are studied, respectively. Finally, the empirical region is selected, and the research results are used for case analysis to verify the effectiveness and operability of the research results.

High voltage cascaded energy storage power conversion system, as the fusion of the traditional cascade converter topology and the energy storage application, is an excellent technical route for large capacity high voltage energy storage system, but it also faces many new problems. How to use the control strategy to play better the advantages of high voltage cascaded energy storage has gotten more and more attention. This paper summarizes the research on power control, balance control, and fault-tolerant control of high voltage cascaded energy storage to provide a reference for related research and engineering application.

Structural metamaterial with negative Poisson’s ratio often has low stiffness due to its porous structure. For engineering applications, the various strategies have been developed to enhance its stiffness but also weaken the negative Poisson effect. In this work, we propose a 3D reinforced re-entrant structure (RRS) by adding arrow structures to the classical re-entrant structure (RS), which is fabricated by photocuring 3D printing of photosensitive resin. The structure-properties correlative mechanism of RRS is systematically analyzed by combining experiment (quasi-static compression experiment) and finite element simulation (ABAQUS). It is found that the equivalent elastic modulus and negative Poisson’s ratio of RRS can be tuned by various structural parameters (i.e. the thickness ratio η, the length ratio of the slant rod α, the length ratio of the vertical rod β, and the angle θ of the re-entrant cells). By optimizing the structure parameters, the equivalent elastic modulus of RRS with the negative Poisson’s ratio of −0.28 can be significantly increase to 13.67 MPa, which is 12.32 times larger than that of RS with the same negative Poisson’s ratio. Due to the flexible design of stiffness and negative Poisson ratio, our proposed 3D reinforced re-entrant structural metamaterial provides a potential way for designing engineering materials with desirable performance.

Quantum key distribution (QKD) system based on passive silica planar lightwave circuit (PLC) asymmetric Mach–Zehnder interferometers (AMZI) is characterized with thermal stability, low loss and sufficient integration scalability. However, waveguide stresses, both intrinsic and temperature-induced stresses, have significant impacts on the stable operation of the system. We have designed silica AMZI chips of 400 ps delay, with bend waveguides length equalized for both long and short arms to balance the stresses thereof. The temperature characteristics of the silica PLC AMZI chip are studied. The interference visibility at the single photon level is kept higher than 95% over a wide temperature range of 12 °C. The delay time change is 0.321 ps within a temperature change of 40 °C. The spectral shift is 0.0011~nm/0.1 °C. Temperature-induced delay time and peak wavelength variations do not affect the interference visibility. The experiment results demonstrate the advantage of being tolerant to chip temperature fluctuations.

When the pulsar signal propagates in the interstellar medium (ISM), the high frequency and low frequency components of the signal reach the radio telescope with a certain delay. Therefore, the pulsar signal will appear energy dispersion, which will broaden the pulse profile, decrease the signal to noise ratio, and even lead to the disappearance of the pulse signal. In this paper, we analyze the sampling, polarization and arrangement of baseband data based on the coherent dedispersion algorithm for the problem of pulsar baseband data dedispersion. We systematically study the coherent dedispersion data processing procedure, and test the pulse profile changes under different FFT block sizes. An optimal selection strategy of FFT block sizes is proposed for reducing the operation time and obtaining a better pulse profile. We propose two methods, one is the generation of ISM transfer function, the other is the pulsar period and phase prediction method at a certain time, and discuss integral and folding strategies. We test the algorithm based on the baseband data of CASPSR and Medusa terminals observed by the Parkes 64 m radio telescope, and analyze the reading and processing methods of baseband data of different terminals. The experimental results show that the phase and amplitude information of the pulse profile processed by our algorithm is basically consistent with the results obtained by DSPSR.

Copyright © 2021 The Author(s). Since the last decade, the non-contact finger seal (NCFS) has attracted an increasing number of researchers due to its inherent flexibility and non-contact features, which can significantly improve the service life and reduce the leakage rate of the finger seals. In this paper, to enhance the NCFS sealing performance, lifting pads with twenty (20) different herringbone groove surface topographies are proposed based on the uniform design method. Numerical analysis is carried out based on the two-way fluid-structure interaction (FSI) method to better mimic the actual working conditions. The analysis of results using statistical tools reveals that the herringbone groove topographies placed on the bottom surface of low-pressure lifting pads can significantly improve the load-carrying capacity and sealing performance. In addition, the correlation analysis of the sealing performance and geometric parameters of the herringbone groove demonstrate that reducing the groove width or increasing the groove internal angle can improve the lifting and leakage capacities. Finally, the optimal herringbone groove and general structure (no groove) are comparatively analysed under variable working conditions, and the results show that the former has much better sealing performance. National Natural Science Foundation of China (Grant Nos. 52075436, 51305343); Education Department of Shaanxi Province (Grant No. 19JC030).

The design of bistable structures is a hot topic in the last decade due to its wide application in smart actuators, energy harvesters, flexible robotics, etc. The characterization of the nonlinear restoring force of bistable structures plays a significant role in modeling and enhancing dynamic performance. However, the traditional nonparametric identification methods may have insufficient accuracy or even be invalid because of numerical differentiation procedures and static fitting. Besides, the modern data-driven sparse regression identification methods rely highly on the assumed nonlinear basis functions and lack interpretability. In this paper, a physics-informed sparse identification method is proposed for the nonlinear restoring force identification of bistable structures. The function of the nonlinear restoring force is physically informed by the derived equation of the Hilbert transform and parameter fitting. Furthermore, sparse identification is conducted based on the free vibration responses of the bistable vibrator. The numerical studies verify the effectiveness of the proposed algorithm under the noise level of 30 dB. Experimental measurement is conducted on a magnetic coupled bistable beam to perform the model identification. It has been demonstrated that the reconstructed dynamic response and nonlinear restoring force both keep in good agreement with the measured ones.

The observational data of high redshift galaxies become increasingly abundant, especially since the operation of the James Webb Space Telescope, which allows us to verify and optimize the galaxy formation model at high redshifts. In this work, we investigate the merging history of massive galaxies at 3 < z < 6 using a well-developed semi-analytic galaxy formation catalog. We find that the major merger rate increases with redshift up to 3 and then flattens. The fraction of wet mergers, during which the sum of the cold gas mass is higher than the sum of the stellar mass in two merging galaxies, also increases from ∼34% at z = 0 to 96% at z = 3. Interestingly, almost all major mergers are wet at z > 3. This can be attributed to the high fraction (>50%) of cold gas at z > 3. In addition, we study some special systems of massive merging galaxies at 3 < z < 6, including the massive gas-rich major merging systems and extreme dense proto-clusters, and investigate the supermassive black hole–dark matter halo mass relation and dual active galactic nuclei. We find that the galaxy formation model reproduces the incidence of those observed massive galaxies, but fails to reproduce the relation between the supermassive black hole mass and the dark matter halo mass at z ∼ 6. The latter requires more careful estimates of the supermassive black hole masses observationally. Otherwise, it could suggest modifications of the modeling of the supermassive black hole growth at high redshifts.

For large spacecraft such as space stations and spacecraft, due to their huge systems, when the power supply equipment and electrical equipment are remote away, it is necessary to lay a long power supply cable. Therefore, when high-power energy transmission is carried out, the voltage drop of the cable will cause the terminal voltage of the electrical equipment to fluctuate with the transmission power. This will have an impact on some load equipment with high demand for electricity, and even shorten the service life of the equipment. In order to ensure the stability of terminal voltage and controllable amplitude of fluctuation, this paper proposes a voltage stabilization technology for long-distance energy transmission in orbit, and the principle analysis, simulation, and experimental verification are carried out to confirm the effectiveness of the technology.

This paper introduces the design, fabrication and characterization of a micro electromagnetic linear actuator integrated with magnetic guide. The actuator consists of a slider, a stator and a magnetic guide. A magnetic guide is used to replace the mechanical rail of conventional linear actuator to ensure the linear motion and to avoid friction. The purpose of this paper is to study the influence of magnetic guide on the dynamic characteristics of electromagnetic linear actuator and measuring techniques for micro-actuators. To test the resistance to motion and output thrust force of the actuator, a cantilever type force sensor is proposed, which can measure the small force in ∼mN order, and the measurement error is less than 3%. Using this sensor, the output thrust measured is higher than 10 mN when 1 A current is applied, and the friction force of the actuator measured is about 7.73 mN. Two-phase square wave and sine wave current are used to drive the actuator, the minimum driving current and frequency of the actuator are less than 0.1 A and 1 Hz respectively. The actuator attains a maximum stable moving speed of 0.15 m s−1 with the input signal frequency of below 250 Hz. In addition, the anti-interference capability of the actuator is evaluated through simulations and experiments. These results show that the actuator can bear an interference 45 times its own gravity in the directions that are perpendicular to the moving freedom, and can adjust the direction of motion automatically when the rotation angle in three orthogonal directions is less than 6°.

The concept of the Internet of things affects the way that people control electrical appliances. Moreover, due to the increasing importance of energy saving, the transformation of electrical power and energy system (EPES) is urgently needed. However, massive waste of energy caused by the inappropriate use of power-consuming equipment and most of the electrical devices controlled in traditional methods. This paper illustrates an Internet of Things (IoT) and edge computing (EC) technique to intellectualize standard energy-consuming equipment via LoRa wireless technology. The proposed system is low power and supports ad-hoc networks. Each node connects to the Internet via a LoRa based gateway. We mainly focus on controlling regular air conditioning and lighting system in office buildings via web pages, apps, etc. To simplify the process of installing the purposed node, several techniques were used to take over the control of traditional power-consuming equipment via user-side. The EC node can receive the short control command and operate itself according to the environment sensing results without control intelligence from cloud server. The experimental results indicate that our intellectualized network can work reliably and save energy-consuming equipment from wasting power.

A single-photon interferometer is a fundamental element in quantum information science. In most previously reported works, single-photon interferometers use an active feedback locking system to stabilize the relative phase between two arms of the interferometer. Here, we use a pair of beam displacers to construct a passively stable single-photon interferometer. The relative phase stabilization between the two arms is achieved by stabilizing the temperature of the beam displacers. A purely polarized single-photon-level pulse is directed into the interferometer input port. By analyzing and measuring the polarization states of the single-photon pulse at the output port, the achieved polarization fidelity of the interferometer is about 99.1±0.1%. Our passively stabilized single-photon interferometer provides a key element for generating high-fidelity entanglement between a photon and atomic memory.

An efficient and timely emergency response to a major accident is more challenging for the exploration and utilization of deep-sea oil and gas fields due to harsh external environment factors. An optimal solution is needed to tackle the external environment changes in the demand for emergency resources. To effectively balance emergency response time and the satisfaction of resource scheduling quantity, this paper proposes a multiple rescue points and multi-objective optimization model to address such challenges. Such model takes into account the environment factors involving wind speed and wave height caused by the variability of the deep-sea monsoon climate. Additionally, to handle the uncertainty of the resource demand at the accident sites, a linear programming and heuristic hybrid algorithm is proposed to help decision makers select the ideal routes and minimal scheduling time of deep-sea emergency resources, as well as the optimal operation season. A case study of a blowout accident is conducted to demonstrate the application of the proposed model and the real-world implications.

The physical role of magnetically semi-hard Co2+ cation addition in enhancing the AC heat induction temperature (T AC) or specific loss power (SLP) of solid (Co x Mn1−x )Fe2O4 superparamagnetic iron oxide nanoparticles (SPIONPs) was systematically investigated at the biologically safe and physiologically tolerable range of H AC (H AC,safe = 1.12 × 109 A m−1 s−1, f appl = 100 kHz, H appl = 140 Oe (11.2 A m−1)) to demonstrate which physical parameter would be the most critical and dominant in enhancing the T AC (SLP) of SPIONPs. According to the experimentally and theoretically analyzed results, it was clearly demonstrated that the enhancement of magnetic anisotropy (K u )-dependent AC magnetic softness including the Néel relaxation time constant τ N (≈τ eff , effective relaxation time constant), and its dependent out-of-phase magnetic susceptibility χ ″ primarily caused by the Co2+ cation addition is the most dominant parameter to enhance the T AC (SLP). This clarified result strongly suggests that the development of new design and synthesis methods enabling to significantly enhance the K u by improving the crystalline anisotropy, shape anisotropy, stress (magnetoelastic) anisotropy, thermally-induced anisotropy, and exchange anisotropy is the most critical to enhance the T AC (SLP) of SPIONPs at the H AC,safe (particularly at the lower f appl < 120 kHz) for clinically safe magnetic nanoparticle hyperthermia.

Neuromorphic implementation of Boltzmann Machine using a network of stochastic neurons can allow non-deterministic polynomial-time (NP) hard combinatorial optimization problems to be efficiently solved. Efficient implementation of such Boltzmann Machine with simulated annealing desires the statistical parameters of the stochastic neurons to be dynamically tunable, however, there has been limited research on stochastic semiconductor devices with controllable statistical distributions. Here, we demonstrate a fully digitized stochastic neurons based on reconfigurable stochastic model that can realize tunable stochastic dynamics in its output sampling characteristics. We emulate the Restricted Boltzmann Machine based on reconfigurable stochastic neurons and leverage the handwritten digits from the MNIST dataset to validate its recognition capabilities and investigate the accuracy of several distinct network parameters.

The Xinjiang Astronomical Observatory Data Center faces issues related to delay-affected services. As a result, these services cannot be implemented in a timely manner due to the overloading of transmission links. In this paper, the software-defined network technology is applied to the Xinjiang Astronomical Observatory Data Center Network (XAO-DCN). Specifically, a novel reconfiguration method is proposed to realise the software-defined Xinjiang Astronomical Observatory Data Center Network (SDXAO-DCN), and a network model is constructed. To overcome the congestion problem, a traffic load-balancing algorithm is designed for fast transmission of the service traffic by combining three factors: network structure, congestion level and transmission service. The proposed algorithm is compared with current commonly load-balancing algorithms which are used in data center to verify its efficiency. Simulation experiments show that the algorithm improved transmission performance and transmission quality for the SDXAO-DCN.

This paper presents data from a 21 cm H i emission drift scan observation of a field partially covering the NGC 4636 galaxy group with the Five-hundred meter Aperture Radio Telescope (FAST). We construct a pipeline to reduce the data, and use SoFiA for source finding. When not contaminated by Radio Frequency Interference (RFI), the FAST observations are capable of detecting all of the galaxies previously detected by the Arecibo Legacy Fast ALFA (ALFALFA) survey in the same region. Comparing to ALFALFA for the detections in common, the FAST data show consistent integrated spectra when the H i disks are spatially unresolved, and capture more flux when the H i disks are resolved. The FAST data further reveal 10 new detections in the region mutually covered with ALFALFA, and 18 new detections beyond the footprint of ALFALFA. All of the new detections have the matching optical counterparts. For the member galaxies of the NGC 4636 group, the detection limit of FAST is deeper by 0.4 dex in H i mass than that of the ALFALFA data. After correcting for the incompleteness caused by RFI contamination, we show that the H i detection rate of galaxies rises steeply with radius out to the virial radius of the group, and flattens beyond that. We also examine four spatially resolved galaxy systems with potential tidal interaction features in detail. Considering that the data have been taken during the “shared-risk” period before a major source of local RFI was eliminated, the results highlight the power of FAST in detecting extragalactic H i.

The effects of GaN/InGaN asymmetric lower waveguide (LWG) layers on photoelectrical properties of InGaN multiple quantum well laser diodes (LDs) with an emission wavelength of around 416 nm are theoretically investigated by tuning the thickness and the indium content of InGaN insertion layer (InGaN-IL) between the GaN lower waveguide layer and the quantum wells, which is achieved with the Crosslight Device Simulation Software (PIC3D, Crosslight Software Inc.). The optimal thickness and the indium content of the InGaN-IL in lower waveguide layers are found to be 300 nm and 4%, respectively. The thickness of InGaN-IL predominantly affects the output power and the optical field distribution in comparison with the indium content, and the highest output power is achieved to be 1.25 times that of the reference structure (symmetric GaN waveguide), which is attributed to the reduced optical absorption loss as well as the concentrated optical field nearby quantum wells. Furthermore, when the thickness and indium content of InGaN-IL both reach a higher level, the performance of asymmetric quantum wells LDs will be weakened rapidly due to the obvious decrease of optical confinement factor (OCF) related to the concentrated optical field in the lower waveguide.

In order to find the action potential hidden in the neural signal, this study proposes a method of detecting the action potential through adaptive threshold, and designs an adaptive threshold detection circuit which can be used for the action potential. Different from the past, the circuit controls the gain by the current of the input signal itself, so as to generate an appropriate adaptive comparison threshold. This circuit not only retains the advantages of the traditional threshold detection method, but also can quickly respond to the input signal, generate an appropriate comparison threshold and detect the action potential without external supervision. The spectre simulation shows that when the power supply voltage is 1.8V, the adaptive threshold generation circuit can accurately detect the action potential without missing or wrong detection.