bluuebunny/crossref_metadata_2025 huggingface dataset:
Rotational invariance in resistor networks: two-point resistances around an n-fold corner
Authors: Perrier Frédéric , Girault Frédéric
Published: October 2020

Equivalent resistances between nodes in a resistor network are related when symmetries are present. In this paper, we establish, using van Steenwijk’s method, that general relations can be derived around any n-corner node, which is a node with n branches holding an n-fold symmetry axis of the network. The expression of the equivalent resistance between an n-corner node and a neighbouring m-corner node can also be given. For networks with four- and five-fold rotational invariance, we illustrate the additional possibilities offered by rotational invariance and Kennelly’s theorem (known as the star-triangle or Y-Δ transform). In particular, we derive general equations for the addition of an n-fold corner on top of any n-fold invariant network. The expressions of two-point resistances for 2 × 4 and 2 × 5 globe networks, for example, are hence obtained. Rotational symmetry, thus, allows exact analytical results to be obtained using elementary methods without heavy calculations, which can be useful for checking the results of advanced numerical methods in practical problems. These didactical examples with resistor networks illustrate the simplifications occurring in a physical system in the presence of rotational invariance.
Auger electron wave packet interferometry on extreme timescales with coherent soft x-rays
Authors: Usenko Sergey , Schwickert David , Przystawik Andreas , Baev Karolin , Baev Ivan , Braune Markus , Bocklage Lars , Czwalinna Marie Kristin , Deinert Sascha , Düsterer Stefan , Hans Andreas , Hartmann Gregor , Haunhorst Christian , Kuhlmann Marion , Palutke Steffen , Röhlsberger Ralf , Rönsch-Schulenburg Juliane , Schmidt Philipp , Skruszewicz Slawomir , Toleikis Sven , Viefhaus Jens , Martins Michael , Knie André , Kip Detlef , Laarmann Tim
Published: October 2020

Wave packet interferometry provides benchmark information on light-induced electronic quantum states by monitoring their relative amplitudes and phases during coherent excitation, propagation, and decay. The relative phase control of soft x-ray pulse replicas on the single-digit attosecond timescale achieved in our experiments makes this method a powerful tool to probe ultrafast quantum phenomena such as the excitation of Auger shake-up states with sub-cycle precision. In this contribution we present first results obtained for different Auger decay channels upon generating L-shell vacancies in argon atoms using Michelson-type all-reflective interferometric autocorrelation at a central free-electron laser photon energy of 274.7 eV.
Single photon simultaneous K-shell ionization/excitation in C6H6: experiment and theory
Authors: Carniato S , Selles P , Ferté A , Berrah N , Wuosmaa A H , Nakano M , Hikosaka Y , Ito K , Žitnik M , Bučar K , Soejima K , Jänkälä K , Cubaynes D , Bizau J-M , Andric L , Khalal M A , Palaudoux J , Lablanquie P , Penent F
Published: October 2020

Single photon simultaneous core ionization/core excitation (K−2V) of the Benzene molecule has been observed experimentally, using synchrotron radiation, by electron coincidence spectroscopy with a magnetic bottle time-of-flight electron spectrometer and reveals a rich spectrum. DFT and Post–Hartree–Fock calculations provide detailed assignments of K−2V states. The specific Auger decay of these states has also been determined experimentally with a new technique to improve the energy resolution.
Photo-spin-voltaic effect in PtMn/Y3Fe5O12 thin films
Authors: Yadav Roshni , Shepit Michael , Li Xu , Lin Ko-Wei , van Lierop Johan , Ruotolo Antonio
Published: October 2020

The photo-spin-voltaic effect is revealed by the presence of a spin voltage generated by photons when a non-magnetic metal (e.g., Pt) is in close proximity to a ferrimagnetic insulator (e.g., Y3Fe5O12 (YIG)). This is attributed to the excited electrons and holes diffusing from the proximized layer near the interface to the metallic surface. By using a dual-ion-beam sputtering deposition technique, a metallic PtMn layer was deposited on YIG /Gd3Ga5O12 (GGG) (111) substrates. We report on the photo-induced-spin voltaic effect in a PtMn/YIG/GGG heterostructure. The sign of the photo-generated voltage was found to switch with magnetic field polarity and its intensity to decrease with increasing PtMn thickness. This indicates that spin-polarized electrons are confined near the interface in the metal. Photo-excitation of these carriers, together with spin–orbit coupling with Pt atoms, is at the origin of the measured transverse voltage. The design may find applications in antiferromagnetic spintronics.
Time- and energy-resolved effects in the boron-10 based multi-grid and helium-3 based thermal neutron detectors
Authors: Backis A , Khaplanov A , Al Jebali R , Ammer R , Apostolidis I , Birch J , Lai C C , Deen P P , Etxegarai M , de Ruette N , Freita Ramos J , Förster D F , Haettner E , Hall-Wilton R , Hamilton D , Höglund C , Kadletz P M , Kanaki K , Karnickis E , Kirstein O , Kolya S , Kraujalyte Z , Laloni A , Livingston K , Löhman O , Maulerova V , Mauritzon N , Müller F , Lopez Higuera I , Richter T , Robinson L , Roth R , Shetty M , Taylor J , Woracek R , Xiong W
Published: October 2020

The boron-10 based multi-grid detector is being developed as an alternative to helium-3 based neutron detectors. At the European Spallation Source, the detector will be used for time-of-flight neutron spectroscopy at cold to thermal neutron energies. The objective of this work is to investigate fine time- and energy-resolved effects of the Multi-Grid detector, down to a few µeV, while comparing it to the performance of a typical helium-3 tube. Furthermore, it is to characterize differences between the detector technologies in terms of internal scattering, as well as the time reconstruction of ∼ µs short neutron pulses. The data were taken at the Helmholtz Zentrum Berlin, where the Multi-Grid detector and a helium-3 tube were installed at the ESS test beamline, V20. Using a Fermi-chopper, the neutron beam of the reactor was chopped into a few tens of µs wide pulses before reaching the detector, located a few tens of cm downstream. The data of the measurements show an agreement between the derived and calculated neutron detection efficiency curve. The data also provide fine details on the effect of internal scattering, and how it can be reduced. For the first time, the chopper resolution was comparable to the timing resolution of the Multi-Grid detector. This allowed a detailed study of time- and energy resolved effects, as well as a comparison with a typical helium-3 tube.
A thermographic data augmentation and signal separation method for defect detection
Authors: Liu Kaixin , Tang Yuwei , Lou Weiyao , Liu Yi , Yang Jianguo , Yao Yuan
Published: October 2020

Non-destructive testing is a popular technique for defect assessment of composite materials, where machine learning models become more important in its data analysis. Nevertheless, deep learning, which has achieved state-of-the-art results in many tasks, has received less attention in this field. Herein, a generative independent component (IC) thermography method is proposed. In detail, a generative adversarial network is implemented for image augmentation, which generates fake thermal images that mimic the patterns of real measurements. In doing this, the sample size is enlarged and the defect information contained in the images is enriched. Then, both the real and fake thermal images are decomposed by IC analysis, which separates the defect signals represented by non-Gaussian sources and the non-uniform backgrounds caused by uneven heating. Consequently, the defect detection results are improved. The performance of the proposed method on a polymer composite specimen demonstrates its effectiveness.
A comparative study on the dielectric response and microwave absorption performance of FeNi-capped carbon nanotubes and FeNi-cored carbon nanoparticles
Authors: Kuang Daitao , Wang Shiliang , Hou Lizhen , Luo Heng , Deng Lianwen , Chen Chuansheng , Song Min , Mead James L , Huang Han
Published: October 2020

The mechanisms responsible for the dielectric response of C-based microwave absorbers remain a long-standing theoretical question. Uncovering these mechanisms is critical to enhance their microwave absorption performance. To determine how different C forms alter the dielectric response of C-based absorbers, FeNi-capped carbon nanotubes (FeNi-CNTs) and FeNi–cored carbon nanoparticles (FeNi-CNPs) are synthesized, and a comparative study of their dielectric responses is then carried out in this study. The as-synthesized FeNi-CNTs and FeNi-CNPs have similar magnetic properties and complex permeabilities, but differ in complex permittivities. It is shown that FeNi-CNTs have a much stronger dielectric loss than FeNi-CNPs. At a thickness of 2.8 mm, a low optimal reflection loss of −32.2 dB and a broad effective absorption bandwidth of 8.0 GHz are achieved for FeNi-CNTs. Meanwhile, equivalent circuit models reveal that the CNT network of the FeNi-CNTs could introduce an electrical inductance that can effectively improve its dielectric loss capability. This study demonstrates that designing a composite with a tailored C form and composition is a successful strategy for tuning its microwave absorption performance. Furthermore, the equivalent circuit modeling is an effective tool for analyzing the dielectric response of the microwave absorbers, as is expected to be applicable for other metal-C composites.
Rapidly-convergent flux-surface shape parameterization
Authors: Arbon R , Candy J , Belli E A
Published: October 2020

We propose a novel flux-surface parameterization suitable for local MHD equilibrium calculations with strongly-shaped flux surfaces. The method is based on a systematic expansion in a small number of intuitive shape parameters, and reduces to the well-known Miller D-shaped parameterization in the limit where some of the coefficients are set to zero. The new parameterization is valid for up-down asymmetric plasmas and provides an improvement to the Miller form. Simultaneously, the method is rapidly convergent and requires only about half the number of shape parameters as a general Fourier representation in the pedestal.
Current structure in the scrape-off layer of a tokamak in a quiescent state
Authors: Rozhansky V , Kaveeva E , Senichenkov I , Sorokina D , Vekshina E , Coster D , McCarthy P , Khromov N
Published: October 2020

Current structure in the scrape-off layer (SOL) of a tokamak is analyzed. It is demonstrated that poloidal currents measured in the experiments are a combination of several current types with different physical nature. Besides the known Pfirsch–Schlüter currents and thermoelectric currents, so-called plate closing currents flowing to/from the divertor plates are also analyzed. The latter close radial currents in the SOL and below/above the X-point in the SOL and private flux region (PFR). In particular, the current flowing to the outer plate in the PFR, opposite to the thermoelectric current, is predicted for the standard single-null configuration and favorable direction of

∇
B

drift. In addition, a pair of currents should flow to and away from the outer plate. In the single-null configuration, they are often masked by a larger thermoelectric current. However, for the connected double null (CDN) case, where the thermoelectric current is strongly reduced due to smaller temperature asymmetry, these currents dominate. The suggested physical model is supported by the results of simulations performed with the SOLPS-ITER transport code. Simulations were done for ASDEX Upgrade (AUG), L- and H-modes, single-null configurations, and for Globus-M H-mode, both disconnected and CDN configurations. Results of the simulations are compared with probe measurements for AUG and Globus-M tokamaks, and reasonable agreement has been found. The role of parallel currents in the formation of the potential maximum/minimum in the vicinity of the X-point for strongly detached regimes is also analyzed.
Delamination imaging in laminated composite plates using 2D wavelet analysis of guided wavefields
Authors: Sha Ganggang , Radzienski Maciej , Soman Rohan , Wandowski Tomasz , Cao Maosen , Ostachowicz Wieslaw
Published: October 2020

Delamination is a type of damage frequently occurring in laminated composite plates. Delamination detection is crucial to ensure structural integrity and safety. This paper presents a delamination imaging algorithm based on the space-wavenumber analysis of guided wavefields using two-dimensional (2D) continuous wavelet transform (CWT). The premise of this algorithm is that delaminations in a structure will alter wavenumbers in the delamination regions. The state of the art uses the short-space Fourier transform (SSFT) for local wavenumber analysis in order to capture these wavenumber alterations. However, window size in local wavenumber analysis using SSFT needs to be determined according to the wavelength in the delamination regions, which is not known a priori. Moreover, window size in SSFT is fixed and cannot adapt to the wavenumber alterations in varying damage scenarios. To address these disadvantages, the 2D CWT is introduced to analyze the guided wavefield data in the space-wavenumber domain leading to 2D CWT-wavefields. The wavenumber alterations induced by delaminations are well isolated in the 2D CWT-wavefields at fine scales. Window size in wavelet analysis is flexibly adapted to guided wavefields from varying damage cases by adjusting wavelet scale factor that is seen as the pseudo-wavenumber. A final damage map is developed by fusing the 2D CWT-wavefield images. The algorithm is successfully used in detecting multiple delaminations in a GFRP plate with the accurate location, size, and shape of each delamination clearly visualized in the final damage map.
Hybrid behavior of a two-dimensional Noguchi nonlinear electrical network
Authors: PELAP François Beceau , NDECFO Jean Emac , DEFFO Guy Roger
Published: October 2020

In this work, the propagation of modulated waves in a nonlinear two-dimensional discrete electrical line is studied. Based on the linear dispersive law, we demonstrate that the network can adopt Hybrid’s behavior due to the fact that, without changing its appearance structure or its parameters values, it can become alternatively, a purely right-handed line, a purely left-handed line or a composite right-left-handed line depending on coupling transverse parameters

L

2

,

C

2

and

k

2

.

Using the reductive perturbation method, a (2+1)-dimensional nonlinear Schrodinger equation governing the dynamics of the small amplitude signals in the network is derived and the impact of the above transverse parameters on the sign of the product of their coefficients is examined. Likewise, backward and forward solitary wave propagations in the system is predicted and analyzed quantitatively and qualitatively. The effects of relevant transverse network parameters on the characteristic parameters of these waves are investigated. We find out that these transverse parameters considerably affect the characteristics and the nature of the waves that are propagated throughout the system.
Laser diagnostics of atomization and combustion of kerosene in a model combustion chamber
Authors: Chelebyan O G , Vasiliev A Yu , Sviridenkov A A , Loginova A A , Kobtsev V D , Kozlov D N , Kostritsa S А , Smirnov V V , Fabelinsky V I
Published: October 2020

The experimental results are presented of implementation of a built-up laser-based diagnostic system at a test rig for investigations of the flame tube heads of aircraft gas turbine engines, both existing and being under development. At this test rig the processes of liquid fuel atomization and mixing with air by flame tube heads of model combustion chambers equipped with newly-developed atomizers, and of combustion of the fuel–air mixture formed in the flow have been studied. These studies enable development and optimization of advanced low-emission engines satisfying the established environmental requirements for the levels of polluting species in the exhaust gases. By using the particle shadow velocimetry technique with a pair of 10 μs delayed 5 ns laser pulses the transverse spatial distributions of average kerosene droplet dimensions, the axial components of their average velocity, and of the average volume flux of the fuel have been measured in the mixture flow axial cross-section. By employing coherent anti-Stokes Raman scattering with 10 ns pump laser pulses at 10 Hz repetition rate during combustion of the produced kerosene–air mixture the statistical characteristics of local ‘instantaneous’ gas temperature fluctuations in the flame, slow variations of these temperatures in time during the combustion process, and transverse distributions of average temperatures in the flame axial cross-section have been measured.
Pulse-amplitude equalization in the monotonic region of the modulator of a rational-harmonically mode-locked fiber ring laser
Authors: Moon Byunghyuck , Kim Yong Soo , Ju Byeong-Kwon , Lee Ju Han , Jhon Young Min
Published: October 2020

We investigate characteristics of the modulator and classify the modulation regions to study pulse-amplitude equalization (PAE) of a rational-harmonically mode-locked fiber ring laser pulses. PAE was accomplished experimentally in a polarization-maintaining laser resonator simply by optimizing the modulator driving power without any additional devices, and stable pulse-amplitude-equalized pulses were obtained in the monotonic region of the modulator at repetition rates of 20 GH, 30 GH, and 40 GH.
Elimination of the zeroth order for four-port power separation by T-ridge metamaterial
Authors: Fu Chen , Wang Bo
Published: October 2020

In this paper, we describe a transmissive grating that eliminates the zeroth order, based on a T-ridged grating structure. The transmission efficiency of the zeroth order under transverse-electric polarization is 0.19%, and the diffraction efficiencies are 22.17% and 21.77% for the ±first and ±second orders, respectively. The transmission efficiency of the zeroth order under transverse-magnetic polarization is 0.11%, and the diffraction efficiencies are 24.12% and 21.93% for the ±first and ±second orders, respectively. In addition, a normalized electric-field diagram is obtained using a finite-element method and the physical mechanism inside the grating is comprehensively analyzed. The diffraction efficiency of each order is calculated for fluctuating values of the wavelength, period and duty cycle and optimized grating parameters. It is concluded that the grating has good tolerance and stability. The analytical results show that the T-ridged four-port grating has good development prospects in the laser field.
Precision measurement of single-electron current with quantized Hall array resistance and Josephson voltage
Authors: Bae Myung-Ho , Chae Dong-Hun , Kim Mun-Seog , Kim Bum-Kyu , Park Suk-In , Song Jindong , Oe Takehiko , Kaneko Nobu-Hisa , Kim Nam , Kim Wan-Seop
Published: October 2020

A single electron pump was incorporated with a quantum Hall resistance and a Josephson voltage for the current evaluation in the framework of Ohm’s law. The pump current of about 60 pA level was amplified by a stable amplifier with a gain of 103 to induce a Hall voltage of about 60 mV level across a 1 MΩ Hall resistance array, which was compared with the Josephson voltage. The gain of the current amplifier was calibrated with a cryogenic current comparator bridge. For two different drive frequencies and repeated thermal cycles, the comparisons demonstrated that the pump current averaged over the first plateau was equal to ef within the combined uncertainty level of 0.3 × 10−6 (k = 1).
Hybrid deep-learning architecture for general disruption prediction across multiple tokamaks
Authors: Zhu J.X. , Rea C. , Montes K. , Granetz R.S. , Sweeney R. , Tinguely R.A.
Published: October 2020

In this paper, we present a new deep-learning disruption-prediction algorithm based on important findings from explorative data analysis which effectively allows knowledge transfer from existing devices to new ones, thereby predicting disruptions using very limited disruption data from the new devices. The explorative data analysis, conducted via unsupervised clustering techniques confirms that time-sequence data are much better separators of disruptive and non-disruptive behavior than the instantaneous plasma-state data, with further advantageous implications for a sequence-based predictor. Based on such important findings, we have designed a new algorithm for multi-machine disruption prediction that achieves high predictive accuracy for the C-Mod (AUC = 0.801), DIII-D (AUC = 0.947) and EAST (AUC = 0.973) tokamaks with limited hyperparameter tuning. Through numerical experiments, we show that a boosted accuracy (AUC = 0.959) is achieved for the EAST predictions by including only 20 disruptive discharges with thousands of non-disruptive discharges from EAST in the training,
combined
with more than a thousand discharges from DIII-D and C-Mod. The improvement in the predictive ability obtained by combining disruption data from other devices is found to be true for all permutations of the three devices. Furthermore, by comparing the predictive performance of each individual numerical experiment, we find that non-disruption data are machine-specific, while disruption data from multiple devices contain device-independent knowledge that can be used to inform predictions for disruptions occurring in a new device.
A dynamical mean-field theory for learning in restricted Boltzmann machines
Authors: Çakmak Burak , Opper Manfred
Published: October 2020

We define a message-passing algorithm for computing magnetizations in restricted Boltzmann machines, which are Ising models on bipartite graphs introduced as neural network models for probability distributions over spin configurations. To model nontrivial statistical dependencies between the spins’ couplings, we assume that the rectangular coupling matrix is drawn from an arbitrary bi-rotation invariant random matrix ensemble. Using the dynamical functional method of statistical mechanics we exactly analyze the dynamics of the algorithm in the large system limit. We prove the global convergence of the algorithm under a stability criterion and compute asymptotic convergence rates showing excellent agreement with numerical simulations.
Research on Optimization of Teaching Mode of Energy and Power Engineering Major Based on ”MOOC + Flipped Classroom” under the Network Technology
Authors: Ma Chuan , Liu Xiaoyan , Liu Lijun
Published: October 2020

There are still many problems in the current network teaching practice of energy and power engineering, which need to be innovated. The new teaching mode based on “MOOC + flipped classroom” is helpful to change the disadvantages of traditional teaching mode and improve students’ application ability. This paper first introduces the teaching mode of “MOOC + flipped classroom”, then analyzes the problems existing in the construction of network courses of energy and power engineering major in colleges and finally gives a new teaching mode design based on “MOOC + flipped classroom” under the network technology.
The modification and Application of Existing Empirical Formula for Predicting Water Inflow Considering the Space of Caverns
Authors: Wang Yong , Zhang Qinghe , Li Ning
Published: October 2020

The prediction of water inflow in cavern is significant for underground engineering, as the inflow has important influence on construction and drainage system. At present, the empirical formulas for predicting inflow are usually based on a single cavern, but the influence of nearby caverns is not taken into account. In order to consider the influence of spacing and radius on water inflow, the inflow in an underground crude oil storage cavern is analyzed by numerical analysis in this paper. The results show that when the s/r < 20, the spacing has great influence on the inflow; when 20<s/r<60, it has some effect on the inflow; and when s/r>60, it almost has no effect on the inflow (s and r represent spacing between caverns and radius). Based on numerical analysis, empirical formulas for predicting water inflow are modified, and the new formula is proposed considering the influence of the spacing. Finally, field data show that the new formula is more suitable for predicting inflow.
Stability Analysis of Flow Control Valve
Authors: Mei Junhua , Liu Wenbin
Published: October 2020

The speed regulating valve is used to control the motion speed of the executive components of the hydraulic system by regulating flow rate for accomplishing the uniform and stable motion. The valve is a combined flow valve by two valves in series, one is a constant differential pressure reducing valve, and the other is a throttle valve. The pressure reducing valve automatically compensates the influence of load, and the pressure is always kept constant. However, it does not change and eliminates the influence of load change on flow, but this flow stability range of the flow control valve is limited, that is, there is a limit to pressure change on the inlet and outlet. This paper introduces the structure principle and flow stability analysis of the flow control valve.
The Simultaneous Determination of Six Components in Zadi-5 Powder by One Test and Multiple Evaluation Methods
Authors: Gao Ling , Lu Ping , Kong Weixue
Published: October 2020

Establish a one-test multi-evaluation method for simultaneous determination of piperine, Costunolide, Dehydrocostus Lactone, dehydrodiisoeugenol, Alantolactone and Isoalantolactone. Method: The drug was extracted with 70% ethanol, using Diamonsil C18 column (4.6mm × 250mm, 5μm), using acetonitrile-0.2% phosphoric acid as mobile phase, gradient elution, flow rate 1.0mL / min; column temperature 30 °C, detection Wavelength 220nm, 343nm. Using Alantolactone as the internal standard, the relative correction factors of the other five components were calculated to determine their content. Results: The six components have a good linear relationship (r> 0.9990) in their respective ranges, and the method precision and accuracy are good. The result of one test and multiple evaluation method for the content of each component in the three batches of samples is close to the standard curve method (RE≤2.23%). Conclusion: This method is accurate, reliable, simple and fast, and can be used for the quality control of Zadi-5 powder.
The Mechanism of Supramolecular Platinum Drugs Acting on Tumor or Tissue
Authors: Qiao Jing , Yuan Xuanju , Zhao Lijun
Published: October 2020

In recent years, the morbidity and mortality of malignant tumors are increasing, and the incidence trend is younger. With the continuous development and application of chemotherapy drugs, chemotherapy has become one of the important means to treat tumors. Platinum drugs are the most commonly used non-specific anti-tumor drugs in the clinical treatment. Cisplatin (CCP) used in this study is a new platinum complex with supramolecular structure synthesized in China, aiming to investigate the effect of CCP on gastrointestinal tumors. The inhibitory effects of carboplatin and cisplatin on hepatocellular carcinoma, gastric cancer, colon cancer and embryonic lung fibroblast pancreatic cancer were determined by cell culture (IC50). The results showed that CCP and carboplatin (CBP) had significant inhibitory effects on liver cancer, stomach cancer, colon cancer and embryonic lung fibroblast pancreatic cancer, and the inhibitory effects were concentration-dependent. The IC50 value of CCP for liver cancer, stomach cancer, colon cancer and embryonic lung fibroblast pancreatic cancer was significantly lower than that of CBP(P<0.05), which was about 1/3∼1/2 of the IC50 value of carboplatin. Meanwhile, the IC50 value of CBP and CCP for embryonic lung fibroblast pancreatic cancer was both more than 240ml/L. It indicates that the supramolecular platinum drugs CCP have a significant inhibitory effect on gastrointestinal tumors, which is stronger than the clinical effect of CBP.
Analysis on the Properties of Modified Steel Slag Asphalt Mixture
Authors: Zhou Yan
Published: October 2020

steel slag property reform is the main form of comprehensive utilization of industrial waste resources. Therefore, this paper combines the theory of steel slag surface modification technology, focusing on the expansion characteristics, aggregate effect and other aspects, to explore the performance of modified steel slag asphalt mixture, in order to achieve clear technical points, to achieve the purpose of comprehensive development and application of social resources.
Research on simulation technology of Shipborne Satellite Communication System
Authors: Jin Rong , Zhao Qianhong , Teng Xiaoyun , Liu Mingbo
Published: October 2020

In this paper, aiming at the architecture, key technologies and member functions of the simulation of the onboard satellite system, a simulation federate model with good hierarchical structure is designed, and a satellite communication simulation system based on HLA is constructed. The key problems such as time unification, fault simulation and real-time visual display are solved. Through the functional simulation of the operation process of the Shipborne Satellite Communication System in the distributed virtual simulation environment, the results show that the system has good interactivity and scalability, and is an effective means to test the reliability of equipment and reduce the risk of scientific test.
Improvement of center-correction reset between guide-model switching for shipborne radar
Authors: Zhang Hao , Tao Min , Xia Jiafeng
Published: October 2020

Antenna servo system of shipborne radar has added digital-guide model and mutual-guide model with the support of center correction in order to capture and track targets conveniently. However, the switching between these two models would create larger step change resulting from the non-reset of center-correction. To this point, this paper represents the working principle of digital guidance, mutual guidance and center correction, and analyses the reason of step change. Then an novel approach is presented to improve the reset of center-correction. The results of experiments indicate that it can avoid the step change caused by the existence of center-correction value, and it enhances the reliability of facility effectively.
A Compounding Method for Calculating Stress Intensity Factor of Pipelines with MSD Structure
Authors: Zhao Jinfang , Zhao Qun , Zhao Yuan
Published: October 2020

Multiple site damage (MSD) often occurs during the service of the nuclear pipeline. The typical structure is multiple cracks on circumferential internal surface of the pipeline. In order to evaluate the reliability of the nuclear pipeline and discuss the damage tolerance of the pipeline with multiple cracks, a compounding method for calculating stress intensity factor (SIF) of pipelines with MSD structure is proposed. Compared with the finite element results, the compounding method is accurate and reliable. The SIF of double cracks and triple cracks are studied by using crack spacing as single factor variable. The result shows that the SIF of MSD cracks can be influenced by the crack spacing of the adjacent crack.
Research on the Development Direction of Mechanical Automation
Authors: Ye Weiwen
Published: October 2020

This article analyzes the current application and development status of mechanical automation in many aspects, and proposes that the essential difference between the two is that modern machinery has intelligent features, while traditional machinery does not, and at the same time it shows the advantages and benefits of all aspects of its products. The fierce still can meet the ever-changing needs of people in production and life. This article takes the system as a starting point, and through listing examples and combining the technologies related to mechanical automation, it proposes the stage goals of the automation control module and the development direction of mechanical design and automation in future development planning.
Synthetic Aperture Radar Image Speckle Noise Suppression and Mine Target Detection
Authors: Yi Xiongsheng , Huang Cailun
Published: October 2020

Synthetic Aperture Radar (SAR) provides a comprehensive, all-weather target monitoring function and is widely used in the military and industrial fields of defense. This article mainly studies a landmine target detection technology based on synthetic aperture radar image processing, shallow buried mines. The detection and identification of military radar has important military significance, which can reduce the casualties caused by landmine explosions. This article first introduces the basic imaging principle of synthetic aperture radar, then introduces the noise processing of SAR images based on the Gamma filter, and finally targets the targets of mine SAR images Features were identified and analyzed.
Stiffness Modeling of Cylindrical Hydrostatic Guideways
Authors: Zhu Jinbo , Jiang Shuyun
Published: October 2020

Static stiffness is an important performance index of the cylindrical hydrostatic guideway. In this paper, the static stiffness model of the cylindrical hydrostatic guideway is studied. Considering the guideway is a system with a rail and a hydrostatic bearing in series, firstly, geometric relationship between the displacement of the table and the deformation of the rail and the displacement of the hydrostatic bearing was derived, the mathematical expression of the stiffness was given. Secondly, based on the beam bending deformation theory, the linear superposition principle was used to derive the deformation equation of the rail under the force of the oil film. Finally, the static stiffness test rig was developed. The static stiffness test was carried out and the theoretical model was verified. The results show that the static stiffness model of the cylindrical hydrostatic guideway established in this paper has high accuracy, which can lay a theoretical foundation for the static characteristics analysis of the cylindrical hydrostatic guideway.
Research on Foundation Defect Identification Technology of Transmission Tower Based on SSP Technology
Authors: Zhang Xingsen , Liang Shirong , Li Junhua , Bian Meihua , Liang Qingguo
Published: October 2020

Transmission tower foundation defect identification has become more and more important. However, conventional detection methods are inefficient, which can cause secondary damage to the structure, and are limited by the inability to achieve large-scale detection. For this reason, the SSP technology is introduced in this paper which is applied to the foundation defect identification of transmission tower. Firstly, the feasibility of applying SSP technology to the foundation defect identification of transmission tower is analyzed. Secondly, the field test flow and data processing of SSP technology for foundation defect identification of transmission tower are introduced. Finally, the basic model of a transmission tower is tested to verify the feasibility of SSP technology for the foundation defect identification of transmission tower.
Lower extremity assisted exoskeleton for people who need rehabilitation training and stairs assistance
Authors: Tan Qilong
Published: October 2020

The Assistant Exoskeleton for Lower Limbs are able to help the following three kind of people walk better: People with congenital defects in the lower limbs, those who have suffered major trauma to their the lower limbs, and those who use the lower limbs for work in a high frequency. For the exoskeleton of this project, aluminum alloy is adopted as the main material, high-power steering gear as the driving part, Arduino Uno as the main board, hard plastic as the lumbar support board, and Velcro as a aid for wearing. In order to make the movement of the exoskeleton more flexible without being too rigid, in this project, an extra set of exoskeleton was manufactured to collect motion data, and a program was written to record the movement of people walking. In the end, this exoskeleton device will mainly provide support for the waist, and share the pressure on the legs, so as to can help anyone with walking fatigue and care for people’s waist and leg health.
Synchronous generator fuzzy PID excitation control system
Authors: Dang Xunyi , Yang Xiaoyu , Yuan Shengrui
Published: October 2020

This paper focuses on the design of excitation controller based on fuzzy PID. According to the whole design process, the input and output variables of fuzzy controller are determined. The domain of language variables and membership functions are determined. The selection of quantization factor, average weighted fuzzy method and scale factor in the process of fuzzification; Based on excitation control experience, 49 fuzzy control rules are established.
Design of Control System Based on Electromagnetic Balance Vehicle
Authors: Peng Wenliang , Li Huise , Hu Ying , Zheng Zexin
Published: October 2020

This paper introduces the design of control system of electromagnetic balance vehicle based on kea128. From two aspects of hardware and software, the control system is designed. The hardware layer includes micro controller, vehicle model attitude measurement and road information recognition module. According to the collected information, combined with filtering algorithm and closed-loop control of upright, speed, direction, etc., through repeated practice verification, the balance car can achieve independent tracking, and can maintain upright state under different track elements, fast and stable operation.
H-inf and State Jumps Control for Switched Singular Systems
Authors: Shi Shuhui , Wang Yajuan , Qi Shuang
Published: October 2020

In this paper, the problem of switched singular systems with exogenous disturbance aiming to minimize H
∞ norm bound and inconsistent state jumps when switch occurs between two different singular subsystems is studied. By designing static output feedback controllers, under which the closed-loop system can be admissible (regular, impulse free and stable) as well as minimizing H
∞ norm bound and instantaneous state jumps at arbitrary switching point. The validity of the main result is illustrated by an example.
The application of CAMSHIFT algorithm based on kernel function in laser tracking moving target
Authors: Qu Jubao
Published: October 2020

According to the characteristics of laser technology, a fast moving target tracking algorithm is designed. Using the spatial information of laser diffuse reflection light points, by adding the kernel function of CAMSHIFT algorithm, the weight of light points in the center of the target is increased by using the weighted histogram, so as to improve the convergence speed of the algorithm and the tracking accuracy of the target. The simulation results show that the improved algorithm can adapt to more complex tracking environment quickly and has better anti-interference, agility and prediction ability.
Research on Threshold Characteristics of Telemetry Receive Channel
Authors: Liu Yang , He Jing , Wu Xingcun , He Qian
Published: October 2020

This article first explains the nature of the threshold effect. Combining various shipborne telemetry channels with regard to the threshold input signal-to-noise ratio, which is the most widely used channel test link for detection, a unified and universal calibration method is proposed: modulation calibration and carrier signal-to-noise calibration According to the different background noise of the channel, it is divided into two ways: radio-frequency wired and wireless. The detailed, theoretical, and highly operable test procedures and steps are given. Finally, the dual-mode loop circuit is implemented. The dynamic tracking of the carrier can significantly reduce the threshold effect.
Application of Geometric Eigensubspace Framework in The Characterization of Atomic Structure
Authors: Jia Jikui
Published: October 2020

The specific atomic structure of materials plays an important role in solid-state physics and materials science because it is inherently related to many physical properties of materials. Various structural fingerprints have been proposed to identify the configuration of atoms. They do not depend on the coordinate system and the order of atoms, so they are more convenient than traditional atomic coordinates. They are unique, but they cannot fully describe the structure of the atom. Therefore, we hope to have a notation that uniquely identifies the atomic configuration and contains as much structural information as possible. This paper proposes a novel and intrinsic representation of atomic structure. We first proposed an extended distance matrix to describe the atomic structure of the cluster. It is different from the traditional distance matrix in that the zero of the diagonal element is replaced with the characteristic quantity of each atom to distinguish different elements. The extended distance matrix contains all the structural information of the cluster. In addition to the overall chirality, through spectral decomposition, the position information of the atoms can be discussed based on the eigenvector coordinate system and the eigensubspace framework. Studies have shown that due to the difference in the number of bonds, the Λ
dec
distance between the diamond atom (the number of bonds is 4) and the other two atoms (the number of bonds is 3) is relatively large, about 0.076; graphene atoms and C
60 atoms the Λ
dec
distance is relatively small, about 0.051.
Research and Design of Electronic Measuring Instrument Based on Single Chip Microcomputer
Authors: Zhang Tianrun , He Xi , Hu Linshan
Published: October 2020

This paper studies and designs a high-precision resistance inductance and capacitance measuring instrument based on single-chip microcomputer. It uses MAX038 monolithic voltage control function generator to generate high-precision sine wave signal flow, through the capacitor or inductor and the standard resistance string to be tested. Connect the circuit, use the voltage ratio calculation method to calculate the capacitance value or the inductance value, use the 51 single-chip microcomputer to control the measurement and calculation results, use the 1602 liquid crystal module to display the value in real time, and the sinusoidal signal generator can realize the amplitude and frequency. In order to improve the accuracy, the measured AC voltage is first passed through the ICL7650 to eliminate the error caused by the lower input resistance of the AD637.The experimental test results show that the measuring instrument has stable performance and high measurement accuracy.
The Design and Simulation of Beidou Navigation Receiver LNA in B3 Frequency Band
Authors: Zang Zhibin , Pang Hui , Liao Baoquan , Ji Fulong , Nie Haitao , Yu Zhixi
Published: October 2020

The Beidou satellite navigation receiver needs to receive Beidou signals efficiently in a complex environment, and the design of receiver front-end is the key link. According to the Beidou receiver front-end system indicators, such as noise figure, gain, etc., we propose a low-noise amplifier design scheme which is based on Infineon’s broadband NPN RF bipolar transistor BFP740FED, and employ ADS to simulation and optimization tests. The results show that the low noise amplifier has a noise factor NF < 0.7dB, gain Gain > 35dB, gain flatness less than 0.5dB, input-output standing wave ratio less than 1.5 in the B3 band. This system has high noise performance of the amplifier, which can support the further development of Beidou navigation receiver application.
Simulation Study on Solenoid Valve of Hydraulic Control Unit
Authors: Qian Feng
Published: October 2020

In the research and development and improvement of the wet double-clutch automatic transmission, the hydraulic control unit has always been the focus of attention in the industry, and the working characteristics of the solenoid valve will directly affect the control effect of the hydraulic control unit, which in turn affects the quality of the vehicle’s shifting action. [1]This article is based on a hydraulic control unit, using its rich component library on the AMESim software platform, according to the working principle of the solenoid valve, the simulation model of various types of solenoid valves in the hydraulic control unit is established, and the exploration design module is used to the various parameters in the valve that are not easy to obtain directly are identified based on genetic algorithm, and the parameters in the model are optimized; then the S function is generated through the interface in AMESim, and each solenoid valve is simulated with the help of the numerical calculation ability of Matlab to obtain The simulation results of the solenoid valve working process are presented.[2, 3].
Design of a Shielded Core Current
Authors: Zhao Mo , Wu Wei , Li Jinxi , Guo Jinghai , Liu Yifei , Wang Wenbing
Published: October 2020

Aiming at the problem that the signal noise ratio (SNR) can’t meet the requirement due to electromagnetic interference in the measurement of coupling current of transmission cable core line in electromagnetic pulse environment, a shielded core line pulse current probe is designed and developed. This paper introduces the measuring principle of the probe, the structure characteristics and development situation, given the characteristics of the probe sensitivity and parameters, such as spectrum method and the calibration parameters, and analyzes its usage in the experimental results show that the design of shielded conductor pulse current probe based on the structure of the original transmission has a better ability to resist electromagnetic interference and pulse signal measurement capability.
Reliability analysis of self-developed mechanical Meta action test-bed based on FTA
Authors: Ge Hongyu , Liu Yuan , Liu Baoqiang , Wang Tuo
Published: October 2020

In view of the complex mechanical product assembly failure frequency and difficult to control the problem. In this paper, based on the independent research and development of the reliability test-bed of the mechanical Meta action unit, the reliability of the worm rotation Meta action test-bed is analyzed by the method of fault tree analysis (FTA). Firstly, the structure model of the action assembly unit of worm rotating Meta is established. By analyzing the assembly condition of the action unit and using the principle and steps of fault tree, the assembly fault tree model of the test-bed of worm action unit is established, and the minimum cut set is obtained. On the basis of the minimum cut set, the importance of each assembly behavior is determined by quantitative analysis The basic events are sorted according to the importance degree; each basic event is determined as the reliability control point, and the reliability control measures of the assembly process of the meta action unit are formulated by analyzing the fault source of the reliability control point. Through quantitative analysis, the probability of the top event is 0.163, and the reliability of the experimental device system is 82.7%. The results show that FTA is simple, easy to understand, universal and reasonable in conclusion to analyze the reliability of the self-developed action unit test-bed. The modeling idea, calculation process and analysis method formed provide a reference for the reliability analysis of the self-developed action unit test-bed.
A new type of pneumatic linear reciprocating actuator
Authors: Li Xiaorui , Wang Xingsong , Tian Mengqian
Published: October 2020

A new type of pneumatic linear reciprocating actuator based on the Sarrus mechanism is presented in this paper, which includes an external rigid deployable frame, and an internal flexible foldable bellows-type airbag, and a set of rubber bands. The actuator has advantages of large stroke, small volume, large expansion ratio, and elongation which can be controlled by air pressure. It can achieve reciprocating linear motion with a larger expansion ratio of 800%. This paper first introduces the structure of the rigid frame and airbag, and introduces the manufacturing process of the airbag under laboratory conditions. Then, the theoretical analysis of the actuator is carried out, and the air pressure displacement characteristic formula is introduced. Finally, the correctness of the characteristic curve is verified by experiments.