bluuebunny/crossref_metadata_2025 huggingface dataset:
Light-induced
psbA
translation in plants is triggered by photosystem II damage via an assembly-linked autoregulatory circuit
Authors: Chotewutmontri Prakitchai , Barkan Alice
Published: August 2020

Significance

Photosystem II (PSII) harbors the water-splitting activity underlying oxygenic photosynthesis. The PSII reaction center protein D1 is subject to photodamage and must be replaced with nascent D1 to maintain photosynthetic activity. How new D1 synthesis is coordinated with D1 damage has been a long-standing question. Our results clarify the nature of the light-induced signal that activates D1 synthesis for PSII repair in plants, and suggest an autoregulatory mechanism in which degradation of damaged D1 relieves a repressive interaction between D1 and translational activators in a complex that functions in PSII assembly and repair. This proposed mechanism comprises a responsive switch that couples D1 synthesis to need for D1 during PSII biogenesis and repair.
Supernova triggers for end-Devonian extinctions
Authors: Fields Brian D. , Melott Adrian L. , Ellis John , Ertel Adrienne F. , Fry Brian J. , Lieberman Bruce S. , Liu Zhenghai , Miller Jesse A. , Thomas Brian C.
Published: August 2020

The Late Devonian was a protracted period of low speciation resulting in biodiversity decline, culminating in extinction events near the Devonian–Carboniferous boundary. Recent evidence indicates that the final extinction event may have coincided with a dramatic drop in stratospheric ozone, possibly due to a global temperature rise. Here we study an alternative possible cause for the postulated ozone drop: a nearby supernova explosion that could inflict damage by accelerating cosmic rays that can deliver ionizing radiation for up to

∼
100

ky. We therefore propose that the end-Devonian extinctions were triggered by supernova explosions at

∼
20
 
pc

, somewhat beyond the “kill distance” that would have precipitated a full mass extinction. Such nearby supernovae are likely due to core collapses of massive stars; these are concentrated in the thin Galactic disk where the Sun resides. Detecting either of the long-lived radioisotopes

Sm

146

or

Pu

244

in one or more end-Devonian extinction strata would confirm a supernova origin, point to the core-collapse explosion of a massive star, and probe supernova nucleosynthesis. Other possible tests of the supernova hypothesis are discussed.
Characterization of mouse di-N-acetylchitobiase that can degrade chitin-oligosaccharides
Authors: Ohno Misa , Miyazaki Masao , Kimura Masahiro , Minowa Yusaku , Sakaguchi Masayoshi , Oyama Fumitaka , Yamashita Tetsuro
Published: August 2020

Di-N-acetylchitobiase (Ctbs) degrades β-1,4 glycoside bonds of the chitobiose core of free asparagine-linked glycan. This study examined whether Ctbs degrades chitin-oligosaccharides to GlcNAc in mammals. We analyzed Ctbs mRNA and protein expression in mouse tissues and characterized enzymatic activity using recombinant mouse Ctbs expressed in Escherichia coli. Ctbs mRNA and protein were expressed in various tissues of mouse, including the stomach. Optimal conditions for recombinant Ctbs were pH 3.0 and 45°C, and the recombinant enzyme was retained more than 94% activity after incubation at pH 3.0–7.0 and below 37°C. The recombinant Ctbs hydrolyzed (GlcNAc)3 and (GlcNAc)6 at pH 3.0 and produced GlcNAc. The Km of Ctbs was lowest with (GlcNAc)3 as a substrate. kcat/Km was fourfold as high with (GlcNAc)3 and (GlcNAc)4 as substrates than with (GlcNAc)2. These results suggest that Ctbs digests chitin-oligosaccharides or (GlcNAc)2 of reducing-end residues of oligosaccharides and produces GlcNAc in mouse tissues.
Where is Love? Tidal deformability in the black hole compactness limit
Authors: Chirenti Cecilia , Posada Camilo , Guedes Victor
Published: August 2020

One of the macroscopically measurable effects of gravity is the tidal deformability of astrophysical objects, which can be quantified by their tidal Love numbers. For planets and stars, these numbers measure the resistance of their material against the tidal forces, and the resulting contribution to their gravitational multipole moments. According to general relativity, nonrotating deformed black holes, instead, show no addition to their gravitational multipole moments, and all of their Love numbers are zero. In this paper we explore different configurations of nonrotating compact and ultracompact stars to bridge the compactness gap between black holes and neutron stars and calculate their Love number k
2. We calculate k
2 for the first time for uniform density ultracompact stars with mass M and radius R beyond the Buchdahl limit (compactness M/R > 4/9), and we find that k
2 → 0+ as M/R → 1/2, i.e., the Schwarzschild black hole limit. Our results provide insight on the zero tidal deformability limit and we use current constraints on the binary tidal deformability

Λ

̃

from GW170817 (and future upper limits from binary black hole mergers) to propose tests of alternative models.
emf generated by squeezing an ellipse
*
Authors: Binder P-M , Devedzhiev Kostadin G , Runyan Alexandra T
Published: August 2020

We study the motional emf generated by squeezing an elliptical conducting loop traversed by a constant magnetic field. The circumference of the loop remains constant in the elastic regime, acting as a non-trivial constraint. We numerically find the dependence of one axis of the ellipse on the other and hence calculate the rate of change in area and the ensuing emf. We discuss possible applications of our findings.
Theoretical and experimental study on scattering of low-energy electrons by dimethyl and diethyl ethers
Authors: Tatreau Gillian , Hlousek Borna A , Zawadzki Mateusz , Khakoo Murtadha A , Bardela Fernanda P , Barbosa Alessandra Souza , Bettega Márcio H F
Published: August 2020

We report a joint theoretical and experimental investigation on low-energy electron scattering by dimethyl and diethyl ethers. The experimental elastic differential cross sections were measured at impact energies from 1 eV up to 30 eV and scattering angle range of 10° to 130°. Theoretical elastic differential, integral and momentum-transfer cross sections are calculated at impact energies up to 30 eV, employing the Schwinger multichannel method implemented with norm-conserving pseudopotentials, in the static-exchange and static-exchange plus polarization approximations. Our experimental and theoretical results for dimethyl and diethyl ether are compared with previous data for their isomers, ethanol and butanol, respectively. These comparisons reveal that although the cross sections for the ether and its respective alcohol present similar magnitudes, the angular behavior of their differential cross sections shows some significant differences. From the analysis of the integral cross sections for electron scattering by dimethyl and diethyl ether, we observe a broad structure, at around 9.5 eV, which we assign as the overlap of several resonant structures.
Five texture zeros for Dirac neutrino mass matrices
Authors: Benavides Richard H. , Giraldo Yithsbey , Muñoz Luis , Ponce William A , Rojas Eduardo
Published: August 2020

In this work, we propose new five texture zeros for the mass matrices in the lepton sector in order to predict neutrino masses. In our approach, we extend beyond the standard model (SM) by assuming Dirac masses for the neutrinos, a feature which allows us to make a theoretical prediction for the lightest neutrino mass in the normal ordering. The textures that were analyzed have enough free parameters to adjust the V
PMNS mixing matrix including the CP-violating phase, the neutrino mass squared differences

δ

m

21

2

,
δ

m

31

2

, and the three charged lepton masses. In order to obtain reliable results, we used two different procedures that are based on the weak basis transformation, a well known technique to analyze textures and their implications for flavor physics. The first method was based on a least-squares analysis to theoretically fit the lepton masses and the mixing parameters to their corresponding experimental values; for this case, the best fit obtained for the lightest neutrino mass was

(

3.9

±

0.8

0.6

)

×
1

0

−
3

eV. The second approach was algebraic, resulting in a lightest neutrino mass consistent with the experimental values and the restrictions arising from the five texture zeros of the mass matrices, and the lightest neutrino mass obtained was (3.5 ± 0.9) × 10−3 eV.
Localization to delocalization transition in a double stranded helical geometry: effects of conformation, transverse electric field and dynamics
Authors: Sarkar Suparna , Maiti Santanu K
Published: August 2020

Conformational effect on electronic localization is critically investigated for the first time considering a double-stranded helical geometry (DSHG) subjected to an electric field. In the presence of electric field the DSHG behaves like a correlated disordered system whose site potentials are modulated in a cosine form like the well known Aubry–André–Harper model. The potential distribution can be modulated further by changing the orientation of the incident field. A similar kind of cosine modulation is also introduced in the inter-strand hopping integrals of the DSHG. Suitably adjusting the orientation of the electric field, we can achieve fully extended energy eigenstates or completely localized ones or a mixture of both. The effects of short-range and long-range hopping integrals along with the chirality on localization are thoroughly studied. Finally, we inspect the role of helical dynamics to make the model more realistic. The interplay between the helical geometry and electric field may open up several notable features of electronic localization and can be verified by using different chiral molecules.
Etch characteristics of magnetic tunnel junction materials using H2/NH3 reactive ion beam
Authors: Kim Ju Eun , Kim Doo San , Gill You Jung , Jang Yun Jong , Kim Ye Eun , Cho Hanna , Won Bok-Yeon , Kwon Oik , Yoon Kukhan , Choi Jin-Young , Park Jea-Gun , Yeom Geun Young
Published: August 2020

Magnetic tunneling junction (MTJ) materials such as CoFeB, Co, Pt, MgO, and the hard mask material such as W and TiN were etched with a reactive ion beam etching (RIBE) system using H2/NH3. By using gas mixtures of H2 and NH3, especially with the H2/NH3( 2:1) ratio, higher etch rates of MTJ related materials and higher etch selectivities over mask materials (>30) could be observed compared to those etching using pure H2( no etching) and NH3. In addition, no significant chemical and physical damages were observed on etched magnetic materials surfaces and, for CoPt and MTJ nanoscale patterns etched by the H2/NH3( 2:1) ion beam, highly anisotropic etch profiles >83° with no sidewall redeposition could be observed. The higher etch rates of magnetic materials such as CoFeB by the H2/NH3( 2:1) ion beam compared to those by H2 ion beam or NH3 ion beam are believed to be related to the formation of volatile metal hydrides (MH, M = Co, Fe, etc) through the reduction of M-NHx( x = 1 ∼ 3) formed in the CoFeB surface by the exposure to NH3 ion beam. It is believed that the H2/NH3 RIBE is a suitable technique in the etching of MTJ materials for the next generation nanoscale spin transfer torque magnetic random access memory (STT-MRAM) devices.
Global gyrokinetic simulations of ITG turbulence in the magnetic configuration space of the Wendelstein 7-X stellarator
Authors: Bañón Navarro A , Merlo G , Plunk G G , Xanthopoulos P , von Stechow A , Di Siena A , Maurer M , Hindenlang F , Wilms F , Jenko F
Published: August 2020

We study the effect of turbulent transport in different magnetic configurations of the Weldenstein 7-X stellarator. In particular, we performed direct numerical simulations with the global gyrokinetic code GENE-3D, modeling the behavior of Ion Temperature Gradient turbulence in the Standard, High-Mirror and Low-Mirror configurations of W7-X. We found that the Low-Mirror configuration produces more transport than both the High-Mirror and the Standard configurations. By comparison with radially local simulations, we have demonstrated the importance of performing global non-linear simulations to predict the turbulent fluxes quantitatively.
Realization of wafer-scale single-crystalline GaN film on CMOS-compatible Si(100) substrate by ion-cutting technique
Authors: Shi Hangning , Huang Kai , Mu Fengwen , You Tiangui , Ren Qinghua , Lin Jiajie , Xu Wenhui , Jin Tingting , Huang Hao , Yi Ailun , Zhang Shibin , Li Zhongxu , Zhou Min , Wang Jianfeng , Xu Ke , Ou Xin
Published: August 2020

Heterogeneous integration of gallium nitride (GaN) film on complementary metal-oxide-semiconductor (CMOS)-compatible Si(100) substrate provides a material platform for future high-performance chips with multiple functions. In this work, a 2 inch wafer-scale single-crystalline GaN film is transferred from commercialized bulk GaN wafer onto Si(100) substrate by combining ion-slicing and modified surface-activated bonding with a sputtering-deposited Si nanolayer. The H+ implantation fluence for the exfoliation of GaN film is as low as 2.5 × 1017 cm−2 and the full width at half maximum of the (0002) x-ray rocking curve of GaN film is 203 arcsec. The sliced bulk GaN wafer is recycled, which is beneficial to reduce the cost and to enhance the mass application of the ion-cutting technique to GaN. The exfoliation mechanism of H-implanted GaN is investigated. The activation energy for slicing GaN is only 2.08 eV owing to the high quality of the GaN wafer, while the wide residual damage band is still an obstacle to improving the quality of the GaN film. The successful demonstration of wafer-scale single-crystalline GaN film on Si(100) substrate will be of great benefit to the integration of high-performance GaN devices and Si CMOS integrated circuits with mature processing technology.
DC electric discharge in processes surface polishes of metal products
Authors: Shaidullin A I , Kuputdinova A I , Akhmadullina L I , Gaysin Al F , Gaysin F M , Gaysin Az F
Published: August 2020

An electric discharge of direct current between the jet anode and the metal cathode is studied in the processes of local surface treatment of metal products at atmospheric pressure. The oscillations of the current and voltage of the discharge, the power invested in the discharge are investigated. The surface temperature of the medium in the combustion zone of the discharge was investigated. The microrelief of the product surface was studied before and after electrolyte-plasma treatment.
Study of corona discharge treated poly(ethylene terephtalate) films by atomic force microscopy
Authors: Galikhanov E M , Lyakhovich A M , Luchkin A G
Published: August 2020

The paper studies poly(ethylene terephthalate) films modified in corona discharge. Surface topography and elastic properties of films dependence on the distance between needle and grounded substrate are obtained by atomic force microscopy.
A the one-dimensional J.J. Thomsons model of radio frequency induction discharge
Authors: Gerasimov A , Kirpichnikov A
Published: August 2020

In this paper, the Thomson’s one dimensional model of radio-frequency induction discharge is considered and some important relations for investigation of its structure are obtained.
Temperature measurement in the PMMA k-phase during combustion in a high enthalpy flowunder the electrostatic field influence
Authors: Zyryanov I A , Pozolotin A P , Budin A G
Published: August 2020

The purpose of present work is to clarify the mechanisms of the electrostatic field influence on the polymers (PMMA) combustion in high enthalpy flows. For this, the PMMA temperature profiles during combustion in a hybrid rocket engine studies were carried out. Based on the results obtained the assumption about the intensification of the substance entrainment from the polymer surface combusting in a high-enthalpy flow under the electrostatic field influence is confirmed.
Application of low-pressure glow discharge in transverse supersonic gas flow
Authors: Israphilov D I , Israphilov I H
Published: August 2020

Article presents application of glow discharge at low pressures in transverse supersonic gas flow limited in part of discharge region. Mathematical model of supersonic flow in a vacuum chamber described. Results of experiments on realization of glow discharge at low pressures due to the organization of a transverse supersonic gas flow are given.
The ionization waves propagation in a long capillary dielectric tube in the absence of surface charge
Authors: Akishev Yu S , Balakirev A A , Karalnik V B , Medvedev M A , Petryakov A V , Trushkin N I
Published: August 2020

The initiation of the electrical breakdown in a narrow tube filled with a gas under reduced pressure requires the voltage higher compared to that for a much broader tube. Besides, at the fixed applied voltage formally sufficient for breakdown, the probability for the breakdown happening in a narrow tube is far from 100%. This probability can be increased appreciably if to organize the surface ionization waves preceding the volume breakdown in a narrow tube. The breakdown development in a long capillary dielectric tube induced by the surface ionization waves was investigated in this work. The experiments were carried out with the use of a quartz capillary tube with a high aspect ratio of length to diameter. The tube was filled with helium at pressures of 1 - 30 Torr. The pre-posited surface charge on the tube wall was absent. It has been found the completed high-current breakdown between two electrodes located at the ends of the long capillary tube develops with a high probability with the presence of surface ionization waves within the tube.
Application of gas discharge with liquid electrolytic cathode to create flow of steam-water plasma
Authors: Tazmeev G K , Tazmeev K K , Timerkaev B A
Published: August 2020

A gas discharge with flowing liquid electrolyte cathode was experimentally investigated under combustion conditions inside an extended chamber with walls made of refractory material. The copper anode was located above the cathode at a distance of 20 cm. The length of the output channel was 50 cm. Heavily diluted aqueous solutions of sodium chloride were used as the electrolyte. The mass velocity of the electrolyte ranged from 8-16 g/s. A three-phase two-half-wave rectifier with voltage at the output of 2100 V served as a power source. The discharge burned stably without a ballast resistor. A plasma flow with mass velocity of 1.0-1.7 g/s in the power range of 25-30 kW was obtained. The total heat loss through electrodes did not exceed 30% of power consumption.
The effect of gas injection on energy characteristics of high-current gas discharge with liquid electrolyte cathode
Authors: Tazmeev K K , Tazmeev A K , Dautov I G
Published: August 2020

A gas discharge with flowing liquid electrolyte cathode was studied experimentally in high-current combustion conditions under conditions of gas injection into the discharge chamber. The interelectrode distance was 20 cm. Aqueous solutions of sodium chloride with specific electrical conductivity of 10–12 mS/cm were used as electrolyte. The discharge current varied within 14-20 A. The studies were carried out with air blowing at a mass flow rate of up to 2.2 g/s. It is shown that air blowing leads to an increase in the discharge current and decrease heat losses through electrodes.
Gas-flame spraying of babbit materials on parts of friction units
Authors: Fedyaev V L , Galimov E R , Kusk O G , Kusk A O , Belyaev A V , Sirotkina L V
Published: August 2020

The questions of applying on the working surfaces of the sliding friction units of babbitt coatings by gas-flame spraying are considered. The operating conditions of babbit bearings are discussed, the main causes and types of their destruction are determined. The widely used technologies for applying babbitt coatings with the method of flame spraying are compared. Experimentally, using the methods of mechanical tests, qualitative and quantitative analysis of the metal structure in control samples, the influence of the main operating parameters of the deposition on the porosity of the babbit coating material, its adhesion to the substrate, wear resistance, and other performance indicators are studied. Rational sputtering distance, the temperature of heating the surface of the substrate before sputtering are established, which ensure optimal values of these indicators. As a result of the analysis of the experimental data, regression relations were obtained characterizing the dependences of the adhesion strength, wear resistance on design (coating thickness), technological (spraying distance), and operational (load, sliding speed) factors.
Study of RF plasma flow at low pressure: electron temperature influence
Authors: Shemakhin A Yu , Zheltukhin V S , Shemakhin E Yu , Pryalukin I S
Published: August 2020

A mathematical model of low-pressure RF plasma flow taking into consideration electron temperature influence is presented. Results of calculations of carrier gas velocity, pressure and temperature as well as electron density and electron temperature in plasma flow are showed. Influence of electric field on electron temperature and plasma flow is analyzed.
Airflow velocity measurement of the electrostatic spray gun
Authors: Fazlyyyakhmatov Marsel , Shaidullin Linar
Published: August 2020

The results of an experimental study of the airflow velocity measurement of the electrostatic spray gun are presented. It has been shown experimentally that airflow velocity rate varies in the range from 1 to 25 m/s depending on the distance from the nozzle of the spray gun and air pressure.
Design and Implementation of DAC Circuit in Waveform Generator
Authors: Zhou Dengrong
Published: August 2020

This article combines the different stages and different levels of various courses such as circuit principle, analog circuit, digital circuit, signal and system, single-chip microcomputer principle, FPGA application and practice, and utilizes the flexibility and interest of the “hardwood classroom” personal multi-functional experimental platform. The simulation design and experimental test of the DAC circuit and signal conditioning and waveform reconstruction circuit in the waveform generator are completed step by step, which fully reflects the process and fun of electronic system design.
Design of High Performance Magnetron Power Supply on the Basis of PWM Power Control
Authors: Li Jianbing , Wu Hao , Xu Tao , Lin Pengfei
Published: August 2020

This paper proposed a kind of high-performance magnetron power supply circuit, the output power of which could be regulated precisely and stably. Based upon the LLC resonant converter with multiplier, efficient power conversion and stable loop control were realized when the switch frequency was near to the resonant frequency. The driving pulses of the switches were controlled by a low-frequency PWM signal, thus realizing the intermittent operation mode. Therefore, the output voltage was in the form of pulsation, which met the requirement of the magnetron. Furthermore, the mean output power of the microwave could be regulated through the PWM duty ratio. An experimental prototype of 1000 W magnetron power supply was completed. As shown in the experiment, the soft switch of this circuit possessed excellent performance. The converting efficiency was higher than 93%; moreover, its output power could be easily adjusted.
Study on the Design of an Optoelectronic Equipment Capable of Detecting Infusion Returns Blood
Authors: Zhu Maolin , Wang Ya , Dong Liming
Published: August 2020

This topic uses photoelectric switch to monitor the characteristics of liquid in the infusion tube to transmit the resistance state. When the transmittance in the infusion tube changes, the signal is captured and fed back to MCU by means of the photoelectric switch to distinguish the return of blood to the infusion tube and the termination of transfusion process or other states. While MCU determines the occurrence of blood returning or the completion of medical transfusion, the alarm reminder function will be triggered. And stepper motor rotates to further clamps the infusion tube to stop the dripping of medicine to prevent the emergence of blood returning, air inflow, etc. The study of this system has a certain research and development value and market potential to alleviate the pain of patients and the burden on family members, greatly improving the work efficiency and fatigue of medical staff.
Research on the Characteristics of Wireless Power Transfer in Ferromagnetic Metal Pipe
Authors: Li Changsheng , Sun Wei , Hu Defu , Liu Yong
Published: August 2020

With the development of society, radio energy transmission technology has been paid more and more attention. However, in the actual application environment, the surrounding metal environment has a significant impact on the radio energy transmission performance. Based on the technology of MRR radio energy transmission, this paper establishes a two coil radio energy transmission model, and analyzes the influence of metal environment on the coil self inductance L, mutual inductance m and coil resistance R of the radio energy transmission system by finite element simulation. On this basis, aiming at the ferromagnetic metal environment, the steel pipe is selected as the research object to study the relationship between coil diameter and mutual inductance in the metal pipe, and the relationship between coil diameter and metal pipe diameter when the maximum mutual inductance is obtained through fitting analysis. At the same time, through the experiment, the mutual inductance between the coils of the wireless energy system in the steel tube is verified, and the experimental results are very consistent with the theory.
Simulation analysis of DC bus short circuit fault in electrochemical energy storage power station
Authors: Ren Hongtao , Zhang Ying , Zheng Shanshan
Published: August 2020

The paper builds a unified equivalent modelling simulation system for electrochemical cells. In this paper, the short-circuit fault of DC bus in energy storage power station is analyzed and simulated. The short circuit of DC bus is composed of three parts: short circuit current provided by energy storage battery, short circuit current provided by power grid and short circuit current provided by DC energy storage capacitor. The factors that affect the amplitude of three kinds of short-circuit current are summarized to provide reference for reducing the DC short-circuit current of energy storage station.
Research on Large-diameter Electro-hydraulic Rotary Table and Its Control System for Deep-water Drilling Rig
Authors: Wang Weixu , Zhang Bin , Li Yunpeng , Dou Wei , Yang Xiuju , Liu Jing , Wang Xinwei
Published: August 2020

With the rapid development of offshore oil and gas drilling equipment industry, it is imperative to study the technology of large-diameter electrically controlled hydraulic rotary table for deep-water drilling rig. Firstly, the hydraulic rotary table design is carried out, which include mechanical structure, electronic control system and hydraulic system design. Secondly, studying the electric control system. The driving force of the electric hydraulic rotary table comes from the hydraulic system, and its control function is mainly realized by the electric control system. This paper analyzes the input and output of the the hydraulic rotary table’s electric control system, completes the design of the hardware system and software system, and puts forward an electric control system scheme of the hydraulic rotary table with perfect function and reasonable configuration. Finally, the conclusion is drawn that the hydraulic rotary table, which is driven by hydraulic motor and rotates at low speed, has the characteristics of compact structure, light weight and large opening size, and can meet the requirement of laying down the riser. It is of great significance to the development of deepwater offshore drilling equipment.
Overview on Risk Assessment of Power System under Typhoon Disaster
Authors: Du J M , Hou H , Tang A H , Jia W Q
Published: August 2020

With the frequent occurrence of typhoon disaster and the resulting large-scale power outage losses, the risk assessment of power system under typhoon damage has been widely concerned. In this paper, we summarize the research status of risk assessment of power system under typhoon damage. Firstly, we introduce several classical wind field model. Secondly, based on the static classical wind field model, we introduce the research progress of typhoon dynamic wind field model. By summarizing the existing risk assessment theory of typhoon disaster, it is divided into system level and component level. In the systematic risk assessment theory, it is further classified into the traditional risk assessment theory based on reliability principle and the new risk assessment theory based on toughness index. Finally, we make a conclusion and outlook on the research of the topic.
Fuzzy control strategy of interconnected power grid AGC system based on particle swarm optimization
Authors: Wang Zaiying , Tao Jiang
Published: August 2020

Frequency is one of the key indicators of power quality. The power load is constantly changing and has uncontrollability. The change of load will affect the frequency of the system. The power system always hopes to keep the frequency as constant as possible, which leads to the problem of frequency control. The mechanism modeling of the multi-region interconnected power grid system is carried out, and the frequency response of the networked system is analyzed by building a simulation platform. Aiming at the shortcomings of “AGC controller” using fuzzy PID control, according to the particle swarm optimization algorithm, a fuzzy adaptive PID controller based on particle swarm algorithm is designed. The simulation results show that the fuzzy adaptive PID controller based on particle swarm algorithm can better improve the dynamic performance of the system.
Noise Analysis and Compensation Strategy of Photoelectric Detection Circuit
Authors: Qin Jiaqiong , Cui Shaobo , Dai Jun
Published: August 2020

A photoelectric detection circuit was designed for improving the accuracy of photoelectric detection and reducing the system error. On the basis of analyzing the noise of the photoelectric detection circuit, the error compensation was proceeded on photoelectric detection circuit using lookup method, linear interpolation method, surface fitting method and adaptive neuro-fuzzy inference method, and the effects of the major error compensation method were compared. The measured data of photoelectric diode experimental platform was used as the sample data. The simulation results in the MATLAB environment demonstrate that under the same condition, the adaptive neuro-fuzzy inference method (ANFIS) can improve the detecting accuracy, and is more effective than lookup method, linear interpolation method, and surface fitting method.
Robust optimization for optimal day-ahead economic dispatch of CCHP considering wind-load uncertainty
Authors: Gu Xiangwen , Chen Xianbang , Liu Yang
Published: August 2020

Distributed wind power generators (WPGs) have been increasingly deployed into power system through combined cooling, heat, and power (CCHP) system. However, uncertain load and intermittent wind power generation adversely affect the economy of the system operation. In order to improve the economy of the CCHP operation, this paper presents a two-stage robust optimization model for the CCHP day-ahead (DA) economic dispatch considering the uncertainties of wind power generation and electric load demand. The model aims at minimizing the total operation cost. The day-ahead first stage is to decide the state and base generation of controllable generators that can withstand the worst-case scenario of the uncertainty while the real-time (RT) second stage is to adjust the generation of the generators according to the actual scenario of the uncertainty. To solve the model, duality theory, Big-M method, and column-and-constraint generation (C&CG) decomposition approach are employed to convert the model into tractable master problem and sub problem, so that a column-and-constraint generation iteration algorithm can be applied to figure out the optimal dispatch solution. Finally, experimental results reveal the effectiveness of the presented model and the employed method.
Analysis of Interior Color Design Based on Computer Virtual Technology
Authors: Xue Shengyan
Published: August 2020

With the development of the times, computer virtual technology has become more and more popular. Computer virtual technology, which has been widely used in many fields, has also contributed to the development of interior color design. Interior design is a highly specialized subject, which often requires designers to spend a lot of energy and time in the process of interior design. Based on this, this paper analyzes the application of computer virtual technology in interior design industry, expounds the application mode of computer virtual technology in interior color design from many aspects, and the influence of computer information technology on interior color design, so as to provide reference for relevant people.
Discussion and Analysis of Computer Information Data Security and Encryption Technology
Authors: Hao Rong Bin
Published: August 2020

With the continuous development of science and technology, Internet technology has become more and more mature, and the advantages of actual information technology have gradually emerged. In the development of such technologies, it can also provide new opportunities for the promotion of computer network technology. This article summarizes the security threats of computer information data based on previous work experience, and discusses the application form of encryption technology in computer information data includes seven aspects: data encryption technology, key management encryption technology, confirmation encryption technology, storage encryption technology, transmission encryption technology, message digest technology, and integrity authentication technology.
Statistical Dependence Test with Hilbert-Schmidt Independence Criterion
Authors: Tian Xinle , He Jiapeng , Shi Yueming
Published: August 2020

This paper studies an approach of nonlinear independence test between random variables. The method is Hilbert–Schmidt independence criterion (HSIC), one of the popular kernel methods for testing statistical dependence between random variables. There are several advantages of using HSIC method. It is easier compared with other kernel methods like the canonical correlation, because it requires no extra regularization terms for an appropriate finite sample behavior. Also, the learning rates of HSIC method is faster because there exists a well-defined population quantity in the estimate. The paper studies the detailed concepts and criterion associated with HSIC, its p-value and sensitivity maps. Results in the experiment about the wine data from UCI data set show the good performance of the approach.
Type Prediction of Student’s Achievement based on Grey Neural Network Optimized by GA
Authors: Wang Jian , Zhang Yuanyuan
Published: August 2020

Students’ learning performance is predicted based on their online learning data, which is of great significance to evaluate the learning effect of school education and the reform and development of online education. In this paper, the characteristics of learning behaviour that constitute the influencing factors of students’ achievement are analysed and screened, and then a prediction model based on neural network and intelligent optimization algorithm is proposed. In this paper, the working principle of grey neural network (GNN) is described, the genetic algorithm (GA) is used to optimize the parameters, and the performance of the model is tested by simulation experiment. The experimental results show that, compared with the reference model, the prediction model optimized by GA parameters shows good prediction performance, and the prediction accuracy remains at a high level.
Iterative Learning Control for Singular Network Control System with Time-Delay and Data Dropout
Authors: Li Zu-Song , He Fu-Gui , Li Shi-Rong
Published: August 2020

Since the object becomes more and more complicated and the existed data dropout and network-introduced time-delay are random and varying in network control system (NCS), the traditional control method is more and more difficult to obtain a good control effect. In this paper, the iterative learning control (ILC) issue for a class of linear continuous singular network control system (SNCS) with time-delay and data dropout is investigated. According to the λ norm and expectation algorithm, the convergence condition of the system is derived. At last, simulation example shows the effectiveness and superiority of the presented method.
Research on Sensor Differential Measurement with Transmission Line Vibration Detection System
Authors: Guo Ji-Yuan , Zhang Fu-Sheng , Liu Xuefei , An Jia-Kun , Zhao Yang
Published: August 2020

In this paper, the transmission line system is used as a model to detect the vibration of the transmission line ground wire. The circuit and transmission characteristics of sensor differential method are discussed in detail. The application of sensor differential method in transmission line vibration detection system is analyzed in time and frequency domain. The experimental results show that sensor differential mode is greatly improved than single sensor on sensitivity, linearity and frequency characteristics in vibration measurement of transmission line.
Graphic User Interface Development of a Digital Phased Array Radar System
Authors: Jia Zhen
Published: August 2020

A graphical user interface (GUI) of a digital phased array radar system is developed to detect and reveal the supposed multi-targets. As the core of the digital radar system, the radar signal generation environment aims at producing a radar echo signal, which is achieved by superposing the simulated radar transmission signals, clutter, jamming signals and radar internal noise linearly; And the radar signal processing environment focuses on processing the radar echo signal to measure multi-target range and velocity information, by employing pulse compression (PC), moving target indication (MTI), moving target detection (MTD) and constant false alarm rate (CFAR) technologies. Every module of the core can be exhibited in the form of MATLAB GUI. In addition, an integrated GUI of the digital phased array radar system is constructed to offer all the multi-target detection and display functions.
New Multi-expert System Based on LSSVM and FI
Authors: Xiong Xiaolong
Published: August 2020

In order to make a diagnosis and obviate the fault more effectively, when complicated mechanical system goes wrong, combining the characteristics of support vector machine, fuzzy integral and expert system, this paper puts forward the integral structure and diagnosis model of multi-expert system based on LSSVM and FI. The model synthesizes the advantages of each algorithm. This method overcomes the insufficiency of traditional expert system such as lack of the mechanism of effective self-study and self-adapt, be difficult to resolve the nonlinear system fault problems. Therefore, it is a convenient way to resolve the multi-sign and multi-reason fault problems of complicated mechanical system.
The Logical Hierarchy of Software Protection Requirements in IR46
Authors: Fan Xuezhong , Li Congcong
Published: August 2020

The updated version of OIML recommendation “Active Electrical Energy Meters” (IR46) requires protection of metrological properties, it provides a new idea for the development of new type watt-hour meter. These requirements are mainly focused on software protection, because for modern static electricity meters, software is the key part for processing and storing legal metrological data. According to the logical relationship between these requirements, this paper analyzes them to form a logical level. The validation methods are analyzed at the same time, which shows the feasibility and the necessity of new generation smart meter.
Switch Migration in SD-IoT Networks for Urban Sensing
Authors: Li Yabo , Jiang Lifen , Zhu Jinqi , Cao Ke
Published: August 2020

Large scale software-defined IoT (SD-IoT) networking need to deploy multiple controllers. How to ensure load balancing among multiple controllers is important to network performance. This paper proposes a switch migration strategy (MMM) which aims to minimize the global migration cost in SD-IoT networks. MMM not only considers the migration cost when making a migration decision, but also takes both the load of the overloaded domain and other domains after migration into consideration when selecting a switch for migration. Simulation experiments prove the effectiveness of the proposed scheme.
Real-time Visual Tracking Based on Convolutional Neural Networks
Authors: Li Rui , Lian Jirong
Published: August 2020

Traditional target tracking is based on target detection. When the target changes significantly, such as occlusion, scale change, the update of the tracking model will waste a lot of space and time resources, resulting in a very slow tracking speed, which cannot meet the actual engineering needs. In view of the above situation, an end-to-end tracking strategy is proposed, which is simpler and faster than the existing technology. The proposed tracker only needs to detect the first frame image and use it as the input of the model, and set the multi-task loss function to predict the position of the next frame of the target and the size of the bounding box. This paper constructs a lightweight network architecture with an additional selection mechanism to avoid wasting resources for global search and matching. Through experiments, good results can be achieved on the standard data set, and tracking speeds close to one hundred frames per second are achieved, which is very competitive with existing advanced trackers.
Treatment of abnormal vibration at the end of large air-cooled generator --The reference of operation and maintenance fault diagnosis of new type phase modifier
Authors: Feng Jianbao , Li Chengzhi , Liu Quan , Ji Peng , Xia Chao , Hu Jianyong , Shen Yongjun , Ma Xiaoguang
Published: August 2020

This paper introduces the abnormal natural frequency at the end of a large-scale air-cooled generator in a power generation company, analyzes the abnormal vibration frequency data at the end of the generator, and solves them successfully, which provides a reference for the state analysis of new high power phase modifier.
Transient flow analysis for multi-state automotive scroll compressors
Authors: Yu Yao , Wang Xiumei
Published: August 2020

Due to the merit of high efficiency, low noise and vibration, scroll compressor has been rapidly developed in recent years. The working process of a scroll compressor is a three-dimensional non-constant compressible viscous flow process. In order to optimize the compressor design for better performance, it is necessary to understand and reveal the detailed mechanism of the unsteady flow inside a scroll compressor. In this paper, a three-dimensional flow-field model of scroll compressor is established. Non-stationary transient simulation of the flow field is carried out by using a combination of dynamic grid and User-Defined-Files. The distribution of temperature, pressure and velocity within the flow field of the work gas under different operating conditions were obtained. In this paper, the flow phenomenon of gas reflux at the suction and discharge ports and its effect on the performance of the scroll compressor was analysed.
The Text modeling method of Tibetan text combining Word2vec and improved TF-IDF
Authors: Tao Jiang , Jia Li , Wan Ma Cao , Meng Jia Hao
Published: August 2020

In view of the problem of ignoring the importance of words in Tibetan text representation, this paper proposes a Tibetan text representation method combining Word2ve and improved TF-IDF. First of all, the method uses the Word2vec model to train all the word vectors of the text, which can capture the semantic information of the text. Secondly, the improved TF-IDF algorithm is used to calculate the weight of each word and word vector in the text. Fusion of Word2vec and improved TF-IDF algorithm to construct a Tibetan text vector representation model based on word vectors and weights. Finally, it uses the BiLSTM neural network model classifier to effectively classify the Tibetan text. The experimental results show that this method is better than the traditional method in the classification of Tibetan text, which verifies the effectiveness of the method.
Study on Quality Influence of Hot Air Drying and Heat pump drying of Xiaocaoba Gastrodia elata
Authors: Cheng Bin , Tan Chao , Tang Xiuying , Chu Zheyu , Min Jiabao , Luo Yinghua
Published: August 2020

This paper takes fresh gastrodia elata of Xiaocaoba as the research object. After the samples are steamed, two processing methods which are hot air drying and heat pump drying are used respectively. The drying temperature is set at 50 degrees for both methods. The results show that different weight gastrodia elata is suitable for different drying methods. The gastrodia elata of 70-105 grams is suitable dried by the hot air drying, while the gastrodia elata of 105-140 grams is better dried by the hot pump drying. The two drying methods had no effect on polysaccharides of samples.
The Cutting Force Simulation of 30CrMnSiA Based on AdvantEdge 2D Broaching
Authors: Hu Zheng , Zhang Wanhao , Li Xin , Gao Hanjun
Published: August 2020

30CrMnSiA alloy steel is a kind of medium carbon quenched and tempered structural steel commonly used in machinery manufacturing industry, which has superior comprehensive mechanical and technological properties. In view of the great difficulty in solving the cutting process of metal by analytical method, this paper simulates the broaching process of 30CrMnSiA by using AdvantEdge software, and studies the influence of cutting parameters, tool geometry parameters, heat exchange coefficient of coolant and other factors on the cutting force. The results show that the cutting force increases with the increase of cutting width, cutting thickness, friction coefficient between tool and chip, and cutting edge radius, while decreases with the increase of relief angle. The cutting force decreases slightly with increasing of rake angle, and it almost does not change with the increase of cutting speed, coating thickness and the heat exchange coefficient of coolant.
Motion Characteristics Analysis of Circulating Roller Screw Pair
Authors: Meng Li Jun , Meng Dongrong
Published: August 2020

With the increasing demand for large thrust and small volume mechanism that converts rotary motion into linear motion, the application of roller screw pair has gradually increased. In order to study the characteristics of the circulating roller screw pair, and solve the common problems in engineering design and manufacturing, this paper has conducted theoretical analysis and research on the working principle, motion characteristics and geometric relations of the circular roller screw. The equation of the motion relationship of the circulating roller screw is derived, and the relationship between the lead formulae and the structural parameters of the cyclic roller screw is given.
The improvement of model predictive control based on three-level three phase inverter
Authors: Liu Feng , Dai Jun
Published: August 2020

To improve the dynamic response of the inverter, the conventional proportional-integral controller and the modulation part are substituted by the finite-control step model predictive control (FCS-MPC) strategy. Unlike the two-level inverter, the drifted neutral point potential is the issue that cannot be neglected. To resolve this issue, the cost function is modified in this paper. Besides, as all of the voltage vectors are employed during optimal research progress in FCS-MPC, the switching frequency is variable, which burdens the filter. The complex calculation progress also burdens the microcontroller. According to the conventional modulation algorithm, the voltage vectors are divided into several groups and the optimal calculations are simplified with them. Based on that modification, the switching frequency is fixed. Finally, the simulation and the experimental results are demonstrated, they reveal the validity and the merits of the proposed algorithm.