bluuebunny/crossref_metadata_2025 huggingface dataset:
Dawn of nitride ferroelectric semiconductors: from materials to devices
Authors: Wang Ping , Wang Ding , Mondal Shubham , Hu Mingtao , Liu Jiangnan , Mi Zetian
Published: February 2023

III-nitride semiconductors are promising optoelectronic and electronic materials and have been extensively investigated in the past decades. New functionalities, such as ferroelectricity, ferromagnetism, and superconductivity, have been implanted into III-nitrides to expand their capability in next-generation semiconductor and quantum technologies. The recent experimental demonstration of ferroelectricity in nitride materials, including ScAl(Ga)N, boron-substituted AlN, and hexagonal BN, has inspired tremendous research interest. Due to the large remnant polarization, high breakdown field, high Curie temperature, and significantly enhanced piezoelectric, linear and nonlinear optical properties, nitride ferroelectric semiconductors have enabled a wealth of applications in electronic, ferroelectronic, acoustoelectronic, optoelectronic, and quantum devices and systems. In this review, the development of nitride ferroelectric semiconductors from materials to devices is discussed. While expounding on the unique advantages and outstanding achievements of nitride ferroelectrics, the existing challenges and promising prospects have been also discussed.
A practical guide to terahertz imaging using thermal atomic vapour
Authors: Downes Lucy A , Torralbo-Campo Lara , Weatherill Kevin J
Published: February 2023

This tutorial aims to provide details on the underlying principles and methodologies of atom-based terahertz imaging techniques. Terahertz imaging is a growing field of research which can provide complementary information to techniques using other regions of the electromagnetic spectrum. Unlike infrared, visible and ultraviolet radiation, terahertz passes through many everyday materials, such as plastics, cloth and card. Compared with images formed using lower frequencies, terahertz images have superior spatial resolution due to the shorter wavelength, while compared to x-rays and gamma rays, terahertz radiation is non-ionising and safe to use. The tutorial begins with the basic principles of terahertz to optical conversion in alkali atoms before discussing how to construct a model to predict the fluorescent spectra of the atoms, on which the imaging method depends. We discuss the practical aspects of constructing an imaging system, including the subsystem specifications. We then review the typical characteristics of the imaging system including spatial resolution, sensitivity and bandwidth. We conclude with a brief discussion of some potential applications.
Analytical insight into dark matter subhalo boost factors for Sommerfeld-enhanced s- and p-wave γ-ray signals
Authors: Facchinetti Gaétan , Stref Martin , Lacroix Thomas , Lavalle Julien , Pérez-Romero Judit , Maurin David , Sánchez-Conde Miguel A.
Published: February 2023

As searches for thermal and self-annihilating dark matter (DM) intensify, it becomes
crucial to include as many relevant physical processes and ingredients as possible to refine
signal predictions, in particular those which directly relate to the intimate properties of DM. We
investigate the combined impact of DM subhalos and of the (velocity-dependent) Sommerfeld
enhancement of the annihilation cross section. Both features are expected to play an important
role in searches for thermal DM particle candidates with masses around or beyond TeV, or in
scenarios with a light dark sector. We provide a detailed analytical description of the phenomena
at play, and show how they scale with the subhalo masses and the main Sommerfeld parameters. We
derive approximate analytical expressions that can be used to estimate the overall boost factors
resulting from these combined effects, from which the intricate phenomenology can be better
understood. DM subhalos lead to an increase of the Sommerfeld effect by several orders of
magnitude (for both s- and p-wave annihilation processes), especially on resonances, which
makes them critical to get sensible gamma-ray signal predictions for typical targets of different
masses (from dwarf galaxies to galaxy clusters).
Simulations of nonlinear interaction between beta-induced Alfvén eigenmode and tearing mode
Authors: Duan Sizhe , Wang Xiaogang , Cai Huishan , Li Ding
Published: February 2023

The nonlinear interaction between the

m

/

n
=
2

/

1

beta-induced Alfvén eigenmode (BAE) and the

m

/

n
=
2

/

1

tearing mode (TM) observed in the HL-2A experiment is systematically studied with the hybrid kinetic-magnetohydrodynamic code M3D-K. It is found that the nonlinear growth of TM can lead to a gradient buildup on the magnetic island (MI) edge, and then triggers the destabilization of the linearly-stable BAE. Then, the triggered BAE together with TM can produce a significant redistribution of energetic particles. For BAE linearly-dominant-unstable case, the TM activity results in the inward motion of BAE mode structure, and the BAE can have a delay effect on the MI saturation. Furthermore, a high-frequency axisymmetric

m

/

n
=
0

/

0

‘breathing’ mode is generated by the mode coupling of BAE and TM, agreeing well with the experimental observation, and causes the synchronized periodic oscillation of MI width.
Cause Analysis of Economizer Tube Leakage in a Biomass Power Plant
Authors: Fang Lulu , Dai Zhen , Zhao Jifeng , Tao Kangning , Zhang Yiwen , Zeng Yong , Chu Xi
Published: February 2023

Aiming at the leakage of economizer tube in a biomass power plant, the leakage mechanism of economizer tube was studied by means of macro analysis, chemical composition analysis, metallographic structure, micro Vickers hardness test and scanning electron microscope. The results show that there is no misuse of materials or unqualified chemical composition in the leaked economizer tube; The metallographic microstructure is ferrite + pearlite, and the spheroidization level is between 2.0 and 2.5, indicating that there is no obvious spheroidization in the pipe section submitted for inspection; At the same time, the micro Vickers hardness value did not decrease significantly; The outer wall of the pipe is yellowish brown and there is delamination and peeling of attachments. A leakage hole can be seen in the middle of the pipe section, and there is obvious thinning at the edge of the hole, indicating that there is corrosion thinning. The chemical components of the corrosion products are mainly Fe and O, and contain a certain amount of Cl, s, P, Si, K, Ca and other alkali metal elements. Therefore, it can be inferred that the main cause of economizer pipe leakage is corrosion thinning.
Effect of Mixed Firing Ethylene Glycol on Combustion and Emission Performance of Model 4190 Diesel Engine
Authors: Wang Qiwei , Zhang Feifei , Lin Hang , Li Pinfang , Fan Jinyu , Ye Zixiao , Huang Jialiang
Published: February 2023

In order to study the influence of ethylene glycol on the combustion and emission of marine diesel engine, a combustion chamber model was established based on 4190ZLC-2 marine medium speed diesel engine by AVL-FIRE simulation software, and the accuracy of the model was verified. The effects of ethylene glycol on the combustion and emission characteristics of diesel engine under different mixing ratios were studied by simulation experiments, and the optimal mixing ratio of ethylene glycol and diesel was obtained under the premise of ensuring the diesel engine to work at full load. The results show that the average pressure in the cylinder and the maximum burst pressure in the cylinder of the dual-fuel engine mixed with ethylene glycol are decreased compared with the original engine under different mixing ratios. Under full load condition, NOx and soot emissions are decreased by increasing ethylene glycol mixing ratio, and CO emission peak is increased but not significantly increased. Through analysis, it can be concluded that when mixing ratio is 15%, final CO emission decreases by 28.6%, final NO emission decreases by 7.9%, and Soot emission decreases by 16.9%.
Model-based Performance Study of Electrically Assisted Turbocharging Diesel Engine
Authors: Duan Baoyin , Yang Chuanlei , Wang Yinyan , Wang Hechun , Wang Binbin , Hu Deng , Wang Baohua
Published: February 2023

Under the low load conditions, the motor drives the compressor to increase the intake of the engine, and under the high load conditions, the motor recovers the excess exhaust energy, which greatly improves the performance of the diesel engine in all aspects. In this paper, the one-dimensional simulation prediction model of TBD620V16 diesel engine is established and checked. On this basis, the external electric auxiliary turbocharging system of motor is established. The influence of motor power on the performance of diesel engine under different working conditions is studied by simulation, and the control strategy is put forward according to the influence of power and economy of diesel engine under low load. Based on this control strategy, the improvement effect of power performance and economy under low load conditions is studied. The results show that there is an optimal motor power in each load condition to make the comprehensive thermal efficiency of diesel engine reach the maximum value. Under low load condition, with the increase of diesel engine speed, the pressure ratio of electrically assisted turbocharged diesel engine is higher and the fuel consumption is lower. When the diesel engine is accelerated from 25% to 30% load condition, the supercharged pressure of electrically assisted turbocharged diesel engine is stabilized for about 3s, and the supercharged pressure is higher when it is stable, and BSFC is significantly lower than that of traditional turbocharged diesel engine.
Increasing Efficiency and Capacity Expansion and Computer Monitoring Reformation of Aibu III Hydropower Station
Authors: Hu Huali , Yang Hongfeng , Chen Bingsen , Tang Zhengquan , Liu Qibo
Published: February 2023

The main problems and potential safety hazards of Aibu III Hydropower Station after extended service are analyzed. In view of the serious waste of hydraulic resources and low equipment efficiency of the power station, the expansion and reconstruction scheme of hydraulic turbine generator units is proposed, and the supporting design and implementation are carried out from all aspects of power station buildings, electrical engineering, calculation monitoring system, etc., which makes full use of hydraulic resources and completely solves the potential safety hazards of the power station, It has received good social and economic benefits. For the hydropower station after technical transformation, the operator on duty can monitor and control the operation status of main electromechanical equipment such as water turbine generator units, main transformers, transmission lines, high-voltage switches, station power, intake gates, unit main valves, and auxiliary equipment of the power station on the operator workstation in the central control room of the power station.
Study on Castor Oil-based Cationic Waterborne Polyurethane and Its Application
Authors: Kuang Guankun , Liu Yan , Qin Ying , Zhou Yuanyuan , Xin Binjie
Published: February 2023

The raw material for polyurethane synthesis is mainly polyols, while traditional polyols come from fossil resources. With the decrease of fossil resources, the synthesis of polyurethane by vegetable oil-based polyols has gradually gained more attention. Castor oil is a kind of plant oil-based polyols, which are the most suitable plant oil polyols because of its non-toxic, biodegradable and trihydroxy structure. Polyurethane synthesized with castor oil as a polyol has many special properties, such as good antibacterial properties, anti-UV properties, good biocompatibility and biodegradable properties. This paper explores the performance and application of castor oil-based cationic waterbased polyurethane (CWPU), which is helpful to promote its performance research and wider application.
Nanocrystalline-to-amorphous Transformation of Silicon Carbide Induced by Atomic Displacement Events
Authors: Chen Dong , Guo Zhiheng , Zheng Danting , Tian Zihan , Shi Qingyang , Mao Yandong
Published: February 2023

In nanocrystalline silicon carbide (NC-SiC), nanocrystalline-to-amorphous (NC-A) transformation can be induced due to atomic displacement events. To evaluate the detailed mechanisms of radiation resistance to amorphization and understand the role of grain boundaries (GBs), it is significantly critical to determine the amorphized dose of NC-SiC by inducing atomic displacements and obtain the information of defect behaviors in the NC-A transformation by using molecular dynamics methods. The results of this study revealed that full amorphization of NC-SiC was achieved by randomly displace (1) a Si atom or (2) a Si/C atom at the same dose of displacement per atom (dpa). The migration of carbon interstitial is the driving force in the amorphization process of NC-SiC according to the low migration energy of carbon in 3C-SiC. Moreover, defect clusters subsequently form and merge into the amorphous domains at the GBs, which will reveal the microscopic mechanism of the irradiation-induced NC-SiC amorphization.
Application Research of Low-density Polypropylene Materials on Door Trim Panels
Authors: Li Shupeng , Li Bo
Published: February 2023

Lightweight design is an important indicator in the process of automobile development, including product structure design, using plastic instead of steel and low density materials and other technical solution, this paper studies low density material technology to achieve lightweight automotive parts. The material system of polypropylene (PP)/elastomer/talc blends(PP+EPDM-TD)was selected to study the combination of different types of PP (homopolymer PP and random PP) and talc powder (mesh number and content) in the material formula. With the goal of the performance of the door panel parts, PP materials with 5% (PP+EPDM-TD5), 10% (PP+EPDM-TD10) and 20% (PP+EPDM-TD20) talc content were developed to verify the material properties. 10% and 20% talc content can meet the requirements. Then, the two materials were comprehensively evaluated from the aspects of parts forming analysis, size verification and application cost, and the low-density material (PP+EPDM-TD10) was finally selected for application to meet the lightweight design requirements of parts.
Effect of Substrate Temperature on Structure of Vacuum Evaporated Zinc-Magnesium Alloy Coating
Authors: Liu Xin , Qiu Xiaopan , Liu Qiuyuan , Xiong Aiming , Teng Huaxiang , Jiang Guangrui , Zhang Wendong , Jiang Sheming , Zhang Qifu
Published: February 2023

In order to solve the problem that the poor plating ability of Galvanized ultra-high strength steel automobile sheet made by traditional continuous hot-dip galvanizing method and the problem that it is difficult to prepare high magnesium (more than 3%) content coated steel sheet by traditional continuous hot-dip galvanizing method. In this chapter, Zn-Mg coating was evaporated at substrate temperature of 50 °C, 100 °C, 150 °C and 200 °C by double source co-evaporation method, and the microstructure and adhesion of single-layer Zn Mg coating were analyzed. The results show that, with the increasing of substrate temperature, the surface grains of zinc magnesium coating have a trend of increasing gradually, but the adhesion of the coating has a trend of decreasing, among which ZnMg-100 coating has the best adhesion.
A Salt Spray Corrosion Prediction Model for Aviation Aluminum Alloy Based on MVO-GRNN Algorithm
Authors: Wang Zequan , Lv Shengli
Published: February 2023

It is very important to focus on the corrosion failure of aluminum alloy materials for airframe because of the increasing of aircraft service time. However, due to the long corrosion test cycle, the number of samples for processing alloy corrosion related data with high cost is very small. In this paper, a corrosion rate prediction model for less sample data sets is proposed: a General Regression Neural Network which using Multi-Verse Optimizer to optimize prarmeters in order to improve accuracy. In this paper, according to the public data of China Corrosion and Protection Network, the content of Mg, Cu, Fe and other components in different types of aluminum alloys, the corrosion environment (Cl− concentration, pH value) and outdoor exposure time are taken as the input and the mass loss per unit area of aluminum alloys is taken as the output of the model. Moreover, using radial basis function for comparsion. The experimental results show that the model has a good fitting effect for predicting the salt spray corrosion of aviation aluminum alloy, and its performance is better than the traditional RBFnetwork.
Method and Mechanism for Adhesion Recovery of Laser-Treated Aluminum Surface Exposed to Hygrothermal Environment
Authors: Li Shuangshuang , Lin Jianping
Published: February 2023

Laser treatment is used to improve the surface adhesion performance of metal materials, including aluminum alloy. However, the adhesion performance of laser-treated aluminum alloy is reduced after the hygrothermal exposure during storage before bonding, obtaining the reliable surface adhesion is a challenge. In this paper, the nanosecond laser-treated aluminum alloy was exposed in a hygrothermal environment with 80°C 95%R.H. for 48h. Scanning electron microscopy, transmission electron microscopy and adhesion strength testing were used to characterize the physical/chemical properties and adhesion reduction of the aluminum surface. Subsequently, a simple and effective method of heat treatment was proposed to recover the adhesion strength. Finally, molecular dynamics (MD) simulation was utilized to explore the underlying recover mechanism. The experimental results revealed a AlOOH layer with ~410 nm thickness was generated on the laser-treated aluminum surface after hygrothermal exposure, which reduced the adhesion strength by 38% (from 30.9MPa to 18.9MPa). After heating at 120 °C for 24 hours, the adhesion strength (30.4MPa) of aluminum surface recovered to the level before hygrothermal exposure. MD results suggested that there are two mechanisms for the adhesion recovery by heat treatment: 1) the atomic kinetic energy of AlOOH increased and the structural order decreased, which strengthened its electrostatic and hydrogen bond interactions with adhesive molecules; 2) the mechanical property of AlOOH were enhanced.
Parameters Identification of Blade Multi-mode Coupled Vibration Based on Blade Tip Timing
Authors: Zhi Fengyao , Duan Fajie , Li Jie , Niu Guangyue , Zhou Qi
Published: February 2023

Health monitoring is crucial for the safe operation of rotating machinery. As an effective technique for measuring the vibration of rotating blades, blade tip timing (BTT) is widely used since its advantages of non-contact and low intervention. During the operation of high-speed blades, the multi-mode coupled synchronous vibration will occur. However, the existing BTT-based methods cannot identify the multi-mode coupled vibration parameters. To solve the problem, a multi-mode coupled vibration model of the blade based on a slender cantilever beam is established, and the contribution of each mode to the blade vibration response is considered. A new Circumferential Fourier Fit (CFF) method for parameters identification of blade multi-mode coupled synchronous vibration is proposed. According to the proposed method, the reconstruction of multi-mode coupled synchronous vibration signals can be realized. Finally, the accuracy of the proposed method is verified by simulation data.
Optimization of Key Hinge Points Position of Folding Arm Ascending Platform Fire Truck
Authors: Wang Zhaojie , Liu Tao , Guo Tong
Published: February 2023

In modern society, high-rise buildings are everywhere, and urban fire protection is also facing many challenges. The primary problem is the fire protection and rescue of high-rise buildings. Therefore, there is always a demand for large ascending platform fire trucks in China. Collapsible boom structure is a common structure of fire truck with ascending platform. The performance of collapsible boom luffing process largely depends on the layout of each hinge point of luffing mechanism. In this paper, the hinge point position of the key structure of the folding arm type 72m ascending platform fire truck is optimized, and the original structure layout is improved, so that the variable amplitude hydraulic cylinder has less force, and the safety performance of the folding arm is improved. In this paper, the kinematic and dynamic models of boom amplitude are established, and two optimization methods, genetic algorithm and SQP algorithm, are adopted to optimize, and the two optimization results have a certain degree of improvement in performance compared with the original layout.
Establishment of Mathematical Model of Different Burr Removal Methods for Automobile Valve Body Parts
Authors: Zhang Chundong
Published: February 2023

In the process of auto body parts processing, machining surface at the junction will produce burrs or flares. The existence of burr will have a bad effect on the machining accuracy, assembly accuracy and appearance quality of parts. In industrial production, the cost of removing these burrs is enormous. In automotive parts, the cost of deburring body parts can account for machining costs15% - 20%. Industry practice has shown that the actual cost of deburring systems increases as the complexity and accuracy of parts increase. Precision parts such as automobile valve body require high precision, and burr is usually removed by grinding. In grinding process, different types of burr will adopt different grinding process to purify, frequent adjustment process will affect the production efficiency, so the combination with the characteristics of grinding, the grinding grain edge radius, equivalent negative rake Angle and other factors into consideration, burr types can be divided into three categories, respectively on the three types of burr mathematical modeling, The removal mechanism of different kinds of burr is explained theoretically, which lays a theoretical foundation for improving efficiency in production practice.
Modeling and Analysis of Vertical Angle Fine-tuning Mechanism Based on Bridge-type Mechanism
Authors: Jiang Bo , Zhang Zijie , Zhou Shun , Chu Yuanbo , Guo Yifan
Published: February 2023

To solve the problem of Angle fine-tuning in the vertical direction of optical devices, we propose an Angle fine-tuning mechanism based on Bridge-type Mechanism. In this paper, we use the method of compliance matrix to establish the statics model of the mechanism and calculate the influence of each parameter on the magnification of the model, then verify it by finite element simulation. Meanwhile, we deduce the calculation formula of compensation value by simulation value and theoretical value to establish Theoretical equations of motion for this mechanism. The results indicate that the simulation results agree well with the theoretical calculation results, after introducing the compensation value, the error caused by the amplification loss of the mechanism can be compensated well to ensure the accuracy of the derived formula.
Parameters Optimization for the Control of Energy Coupler Actuator based on Finite Element Method
Authors: Yang Chenghao , Dai Jin , Xiong Shaoping
Published: February 2023

In this paper, the multi-physics coupled model of the energy coupler actuator (ECA) based on finite element method is built in COMSOL. To achieve some determined indicators, Peak-Hold drive strategy is applied to replace the constant voltage driving plan. Consequently, several groups of Peak-Hold signals are inputted. And the simulation results are analyzed to obtain the optimal parameter sets under the specified target performance. The driving parameters of the model are optimized, resulting in an overall performance improvement. Finally, a solution to find an ideal driving strategy with minimum energy consumption is found in this paper.
Multi-target Emergency Rescue Path Planning in Marine Wind and Wave Environments
Authors: Sun Zhi , Yu Yuanyuan , Mei Yiying , Xiao Xunqiao , Shi Zicang
Published: February 2023

With the development of marine-related industries, the number of tasks at sea has increased, and accidents there happen more frequently as well. Search and rescue are very challenging because of the extreme wind and wave environment at sea. Therefore, the state has been paying more attention to maritime emergency rescue. One part is emergency rescue path planning, which is crucial for helicopter emergency rescue at sea. In this paper, a series of multi-target rescue path solutions are created in order to solve the challenge of multi-target rescue path planning while taking into account sea wind and waves. The rescued targets’ floating trajectory model is first established. Then, a recursive algorithm based on a permutation tree is given in response to the unsteady change of the targets’ position at sea. The rescue path is planned with the goal of cutting down on the helicopter’s search time. Finally, using the multi-target rescue in China’s Taiwan Strait as an example, it is discovered that the overall time needed for the multi-target rescue is decreased by 7.03 minutes, and the efficiency of the rescue is improved by 13.3% in the wind and wave environment at sea. According to the research, the optimal rescue path shortens the time required for multi-target rescue at sea while increasing the effectiveness of helicopter rescue operations.
Failure Analysis of a Deep Pit on the Inner Wall of Water Wall Tube in a Power Plant
Authors: Zhang Yiwen , Fang Lulu , Tao Kangning , Chu Xi , Dai Zhen
Published: February 2023

A deep pit on the inner wall of a water wall tube of a 600MW boiler was found at the extension end of the front of the furnace during an overhaul after 200 thousand hours of operation. To investigate the causes of the failure, various techniques including macroscopic inspection, chemical composition analysis, microstructural analysis, mechanical performance testing, scanning electron microscope (SEM) observation and energy dispersive spectroscopy (EDS) analysis were carried out. The results of investigations showed that the chemical composition of the as-received tube conformed with SA-178 Grade C and the mechanical properties were qualified. EDS analysis revealed that the main elements of the deposit on the surface of the pit were iron and oxygen, along with phosphorus, potassium and aluminium, which were identified with the constitutes of the under deposit corrosion products. Based on the results, the cause of the failure is under deposit corrosion. Possible measures to combat the corrosion were proposed.
An Anti-disturbance Control Algorithm for Permanent Magnet AC Servo System
Authors: Liu Huan , Zhang Xiaomin , Guo Lanjie , Che Mingshuo
Published: February 2023

Permanent magnet AC servo system is widely used in aerospace, industrial robots, petrochemical equipment and so on. In order to improve the anti-interference control performance of the permanent magnet AC servo system, in this paper, a non-singular terminal sliding mode controller based on the extended state observer is designed for the permanent magnet synchronous motor control system using the resolver as the angle sensor. The proposed algorithm uses the extended state observer to observe disturbance while realizing demodulation, and then uses the non-singular terminal sliding mode controller to realize high-precision anti-interference speed control. The proportion of the symbol term in the sliding mode controller can be reduced by compensating the disturbance observation term, thereby effectively suppressing the sliding mode chattering and improving the anti-interference performance of the system. Simulation results show that the proposed method has better control performance than the traditional PID control method in both steady-state accuracy and dynamic performance.
Research on Modeling and Control Algorithm of Self-Balancing Platform of Spraying Robot
Authors: Ye Fan , Su Yuanping
Published: February 2023

In order to improve the driving stability of the tracked vehicle robot with agricultural spray in mountainous complex terrain, an automatic leveling device of the medicine box was designed to adjust the center of gravity of the tracked vehicle during driving by controlling the sidle Angle of the tracked vehicle. Because in the spraying process, the liquid in the medicine box is constantly reduced, which produces a certain load disturbance to the control system. In this paper, an adaptive controller is designed based on the mathematical model of self-balancing platform. Experiments in Matlab/Simulink show that the control method can effectively control the system.
Design of Spaceborne Stepper Motor Driver Based on FPGA
Authors: Zhang Chao , Zhang Ai , Chen Huanhong , Li Jing , Zhang Xiaomin , Jiu Yuanwei
Published: February 2023

In order to meet the specific application requirements of stepper motor in space optical remote sensor, such as large load current, low operating frequency, sufficient safety margin, anti radiation and other space environment indicators, a spaceborne stepper motor driver based on antifuse Field Programmable Gate Array (FPGA) is designed. The driver consists of power conversion module, control module, drive module, and position detection module. Using P-channel Metal-Oxide-Semiconductor Field-Effect Transistor (MOSFET) and N-channel MOSFET to design bipolar drive circuit, the driver hardware circuit is simple and the software resource occupancy rate is low. Through the experiments of the dual functions of logic protection circuit in hardware and dead zone protection in software, it is verified that the design of spaceborne stepper motor driver based on FPGA meets the requirements of space optical remote sensor mechanism control.
Structural Design and Simulation Analysis of Quadruped Tree Climbing Robot
Authors: Jiang Hancheng , Yu Baojun , Qi Xin , Pan Chenhao , Yang Jinfeng
Published: February 2023

Aiming at the problems of large size and complex structure of the existing tree-climbing robot, a new structure of the quadruped tree-climbing robot is designed based on the structure of the existing quadruped tree-climbing robot. We established a mathematical model using robotics, and carried out a positive kinematics analysis of the overall structure. The finite element simulation analysis of the key components and the simulation and verification of the transmission core components are carried out. The overall structure of the redesigned four-legged tree climbing robot is simple, weight, small endurance, high endurance and high finite element results show the grasping mechanism The reasonable stress distribution of the frame design is more uniform, and the robot has strong stability in the process of climbing trees.
The EMC Design of Flap and Slat Electronic Control Unit
Authors: Han Bing
Published: February 2023

A brief description of EMC (electromagnetic compatibility) design in FSECU (Flap and Slat Electronic Control Unit) is proposed. FSECU (Flap and Slat Electronic Control Unit) is the core component of High Lift System. The FSECU’s EMC design for case, I/O interface circuit, ground and PWB is described in detail. In parallel, the analysis for the electromagnetic environment difference of HLS is proposed. The EMC design methodology of FSECU is introduced, which includes the chassis, interface circuit, grounding and PWB. The requirements of controlling the electromagnetic leakage and interference are satisfied by using this way. Several tests of DO-160G are to be performed and the EMC requirements need to be met.
Secondary electron emission characteristics of alumina coating on metallic substrate prepared by atomic layer deposition
Authors: Wei Wenlu , Yan Baojun , Heng Yuekun , Liu Shulin , Zhang Binting , Peng Huaxing , Wang Yuman , Wen Kaile
Published: February 2023

The main objective of this study is to research the
secondary electron emission characteristic of different thickness
alumina coatings which are prepared by atomic layer deposition (ALD)
technique on several metallic secondary-emitting materials. The
experimental results reveal that secondary electron yield (SEY)
property concerned with the metal work function and the surface
topography of alumina coatings when coating thickness is in the
nanometer level. In addition, after utilizing SEY measurement setup
and pulsed electron gun, the SEY curves of metallic substrates with
different thickness alumina coatings and primary energy (PE) of
incident electron could be measured. From an analysis of the SEY
curves, some key parameters related to secondary electron emission
characteristics such as the maximum SEY value and its corresponding
PE of incident electron, and the penetration depth of incident
electron can be obtained. Furthermore, basing on the ALD technique
and on the SEY results of stainless steel substrate coated with
80-cycle alumina thin film, a novel 18-stage discrete dynode
electron multiplier (DDEM) was fabricated and tested. The gain of
DDEM 1.6× 106 was obtained.
Robust surface profile envelope estimation using a beam-surface contact model
Authors: Groche T , Seewig J
Published: February 2023

An important tool for the functional characterization of technical surfaces are envelope estimation techniques. This paper describes a new method for generating profile envelope lines based on a simplified beam-surface contact model with intuitive parameterization. The method is closely related to spline filters and shares some of their positive characteristics such as smoothness and robustness against isolated outliers. Unlike spline filters, the proposed method does not calculate mean lines, but envelope lines. Several examples of calculated profile envelopes of sintered surfaces are shown and a comparison with morphological methods, the state-of-the-art method for envelope estimation, is presented.
A novel self-separating silicon nanowire thin film and application in lithium-ion batteries
Authors: Li Haibin , Kato Shinya , Ishii Yosuke , Kurokawa Yasuyoshi , Soga Tetsuo
Published: February 2023

Nano silicon structures are important materials for modern electronic devices and have been widely researched with regard to photoelectricity, thermoelectricity, and lithium-ion batteries. However, since the nano silicon structures fabricated by conventional methods cannot be separated from silicon substrates, reuse of the substrate is restricted. Here, we propose a simple fabrication method to separate the nano silicon structures from the silicon substrates, which allows the reuse of the substrates. The fabrication was processed at room temperature, which allows large-area fabrication and is not restricted by the substrate thickness. Honeycomb structures of different length scales observed on both the nano silicon structure and the substrate suggest that the separation occurred due to the amplification of the silicon crystal defects. The nano silicon structures comprised porous silicon with an excellent specific surface area of 480 m2 g−1 and a mean pore diameter of 5.7 nm. Moreover, the nano silicon structures show good potential as anode materials for lithium-ion batteries wherein the measured reversible capacity was 1,966 mAh g−1 after 100 cycles. Based on the proposed method and morphological characteristics, the fabricated nano silicon structures can be considered a low-cost material with suitable applications in the energy field.
On dynamical gaskets generated by rational maps, Kleinian groups, and Schwarz reflections
Authors: Lodge Russell , Lyubich Mikhail , Merenkov Sergei , Mukherjee Sabyasachi
Published: February 2023

According to the Circle Packing Theorem, any triangulation of the Riemann sphere can be realized as a nerve of a circle packing. Reflections in the dual circles generate a Kleinian group

H
H

whose limit set is a generalized Apollonian gasket

Λ
H

\Lambda _H

. We design a surgery that relates

H
H

to a rational map

g
g

whose Julia set

J

g

\mathcal {J}_g

is (non-quasiconformally) homeomorphic to

Λ
H

\Lambda _H

. We show for a large class of triangulations, however, the groups of quasisymmetries of

Λ
H

\Lambda _H

and

J

g

\mathcal {J}_g

are isomorphic and coincide with the corresponding groups of self-homeomorphisms. Moreover, in the case of

H
H

, this group is equal to the group of Möbius symmetries of

Λ
H

\Lambda _H

, which is the semi-direct product of

H
H

itself and the group of Möbius symmetries of the underlying circle packing. In the case of the tetrahedral triangulation (when

Λ
H

\Lambda _H

is the classical Apollonian gasket), we give a quasiregular model for the above actions which is quasiconformally equivalent to

g
g

and produces

H
H

by a David surgery. We also construct a mating between the group and the map coexisting in the same dynamical plane and show that it can be generated by Schwarz reflections in the deltoid and the inscribed circle.
Splitting integrators for stochastic Lie–Poisson systems
Authors: Bréhier Charles-Edouard , Cohen David , Jahnke Tobias
Published: February 2023

We study stochastic Poisson integrators for a class of stochastic Poisson systems driven by Stratonovich noise. Such geometric integrators preserve Casimir functions and the Poisson map property. For this purpose, we propose explicit stochastic Poisson integrators based on a splitting strategy, and analyse their qualitative and quantitative properties: preservation of Casimir functions, existence of almost sure or moment bounds, asymptotic preserving property, and strong and weak rates of convergence. The construction of the schemes and the theoretical results are illustrated through extensive numerical experiments for three examples of stochastic Lie–Poisson systems, namely: stochastically perturbed Maxwell–Bloch, rigid body and sine–Euler equations.
The Vicissitudes of Slave Life.
Authors: Douglass Frederick
Published: February 2023

Death of old Master’s son Richard, speedily followed by that of old Master — Valuation and division of all the property, including the slaves — Sent for to come to Hillsborough to be valued and divided — Sad prospects and grief — Parting — Slaves have no voice in deciding their own destinies — General dread of...
Experience in St. Michaels.
Authors: Douglass Frederick
Published: February 2023

St. Michaels and its inhabitants — Capt. Auld — His new wife — Sufferings from hunger — Forced to steal — Argument in vindication thereof — Southern camp-meeting — What Capt. Auld did there — Hopes — Suspicions — The result — Faith and works at variance — Position in the church — Poor Cousin Henny — Methodist Preachers — Their disregard of the slaves — One exception — Sabbath-school — How and by whom broken up — Sad change in my prospects — Covey,...
Life As a Freeman.
Authors: Douglass Frederick
Published: February 2023

Loneliness and Insecurity — ‘Allender’s Jake’ — Succored by a sailor — David Ruggles — Marriage — Steamer J. W. Richmond — Stage to New Bedford — Arrival there — Driver’s detention of baggage — Nathan Johnson — Change of name — Why called ‘Douglass’ — Obtaining work — The Liberator and its editor.
Secession and War.
Authors: Douglass Frederick
Published: February 2023

Recruiting of the 54th and 55th Colored Regiments — Visit to President Lincoln and Secretary Stanton — Promised a Commission as Adjutant-General to General Thomas — Disappointment.
Living and Learning.
Authors: Douglass Frederick
Published: February 2023

Inducements to a political career — Objections — A newspaper enterprise — The new National Era — Its abandonment — The Freedmen’s Savings and Trust Company — Sad experience — Vindication.
Weighed in The Balance.
Authors: Douglass Frederick
Published: February 2023

The Santo Domingo controversy — Decoration Day at Arlington, 1871 — Speech delivered there — National colored convention at New Orleans, 1872 — Elector at large for the State of New York — Death of Hon. Henry Wilson.
Defeat of James G. Blaine.
Authors: Douglass Frederick
Published: February 2023

Causes of the Republican defeat — Tariff and free trade — No confidence in the Democratic party.
The Campaign of 1888.
Authors: Douglass Frederick
Published: February 2023

Preference for John Sherman — Speech at the convention — On the stump — The tariff question.
Administration of President Harrison.
Authors: Douglass Frederick
Published: February 2023

Appointed Minister to Haïti — Unfriendly criticism — Admiral Gherardi.
Continued Negotiations For The MÔle St. Nicolas.
Authors: Douglass Frederick
Published: February 2023

Unfortunate delay — Renewed authority from the United States — Haïti’s refusal — Reasons for the refusal — The Clyde contract — A dishonest proposition — A strange demand — Haïti’s mistake — Bad effect of the Clyde proposition — Final words.
WINTHROP’S ADVENTURE
Authors: Lee Vernon , Worth Aaron
Published: February 2023

I

All the intimates at the villa S ——  knew Julian Winthrop* to be an odd sort of creature, but I am sure no one ever expected from him such an eccentric scene as that which took place on the first Wednesday of last...
CHAPTER II
Authors: Austen Jane , Mullan John
Published: February 2023

Mr. Weston was a native of Highbury, and born of a respectable family, which for the last two or three generations had been rising into gentility and property. He had received a good education, but on succeeding early in life to a small independence,...
CHAPTER VII
Authors: Austen Jane , Mullan John
Published: February 2023

The very day of Mr. Elton’s going to London produced a fresh occasion for Emma’s services towards her friend. Harriet had been at Hartfield, as usual, soon after breakfast; and after a time, had gone home to return again to dinner: she returned, and...
CHAPTER XI
Authors: Austen Jane , Mullan John
Published: February 2023

Mr. Elton must now be left to himself. It was no longer in Emma’s power to superintend his happiness or quicken his measures. The coming of her sister’s family was so very near at hand, that first in anticipation and then in reality, it...
CHAPTER XIV
Authors: Austen Jane , Mullan John
Published: February 2023

Some change of countenance was necessary for each gentleman as they walked into Mrs. Weston’s drawing-room; — Mr. Elton must compose his joyous looks, and Mr. John Knightley disperse his ill-humour. Mr. Elton must smile less, and Mr. John Knightley more, to fit them for the...
CHAPTER XVI
Authors: Austen Jane , Mullan John
Published: February 2023

The hair was curled, and the maid sent away, and Emma sat down to think and be miserable. — It was a wretched business, indeed! — Such an overthrow of every thing she had been wishing for! — Such a development of every thing most unwelcome! — Such a blow for Harriet! — ...
CHAPTER XVII
Authors: Austen Jane , Mullan John
Published: February 2023

Mr. and Mrs. John Knightley were not detained long at Hartfield. The weather soon improved enough for those to move who must move; and Mr. Woodhouse having, as usual, tried to persuade his daughter to stay behind with all her children, was obliged to...
CHAPTER I
Authors: Austen Jane , Mullan John
Published: February 2023

Emma and Harriet had been walking together one morning, and, in Emma’s opinion, been talking enough of Mr. Elton for that day. She could not think that Harriet’s solace or her own sins required more; and she was therefore industriously getting rid of the...
CHAPTER II
Authors: Austen Jane , Mullan John
Published: February 2023

No misfortune occurred, again to prevent the ball. The day approached, the day arrived; and, after a morning of some anxious watching, Frank Churchill, in all the certainty of his own self, reached Randall’s before dinner, and every thing was safe.

No second meeting had...
CHAPTER XIV
Authors: Austen Jane , Mullan John
Published: February 2023

What totally different feelings did Emma take back into the house from what she had brought out! — she had then been only daring to hope for a little respite of suffering; — she was now in an exquisite flutter of happiness, and such happiness moreover as she...
CHAPTER XVII
Authors: Austen Jane , Mullan John
Published: February 2023

Mrs. Weston’s friends were all made happy by her safety;* and if the satisfaction of her well-doing could be increased to Emma, it was by knowing her to be the mother of a little girl. She had been decided in wishing for...
The Street
Authors: Melville Herman , Blum Hester
Published: February 2023

If I had been astonished at first catching a glimpse of so outlandish an individual as Queequeg circulating among the polite society of a civilized town, that astonishment soon departed upon taking my first daylight stroll through the streets of New Bedford....

In thoroughfares...
Biographical
Authors: Melville Herman , Blum Hester
Published: February 2023

Queequeg was a native of Kokovoko, an island far away to the West and South. It is not down on any map; true places never are.

When a new-hatched savage running wild about his native woodlands in a grass clout, followed by the nibbling goats,...
Wheelbarrow
Authors: Melville Herman , Blum Hester
Published: February 2023

Next morning, Monday, after disposing of the embalmed head to a barber, for a block, I settled my own and comrade’s bill; using, however, my comrade’s money. The grinning landlord, as well as the boarders, seemed amazingly tickled at the sudden friendship which had...
His Mark
Authors: Melville Herman , Blum Hester
Published: February 2023

As we were walking down the end of the wharf towards the ship, Queequeg carrying his harpoon, Captain Peleg in his gruff voice loudly hailed us from his wigwam, saying he had not suspected my friend was a cannibal, and furthermore announcing that he let...
All Astir
Authors: Melville Herman , Blum Hester
Published: February 2023

A day or two passed, and there was great activity aboard the Pequod. Not only were the old sails being mended, but new sails were coming on board, and bolts of canvas, and coils of rigging; in short, everything betokened that the ship’s preparations...
The Lee Shore
Authors: Melville Herman , Blum Hester
Published: February 2023

Some chapters back, one Bulkington was spoken of, a tall, new-landed mariner, encountered in New Bedford at the inn.

When on that shivering winter’s night, the Pequod thrust her vindictive bows into the cold malicious waves, who should I see standing at her helm but...
The Advocate
Authors: Melville Herman , Blum Hester
Published: February 2023

As Queequeg and I are now fairly embarked in this business of whaling; and as this business of whaling has somehow come to be regarded among landsmen as a rather unpoetical and disreputable pursuit; therefore, I am all anxiety to convince ye, ye landsmen,...
Ahab
Authors: Melville Herman , Blum Hester
Published: February 2023

For several days after leaving Nantucket, nothing above hatches was seen of Captain Ahab. The mates regularly relieved each other at the watches, and for aught that could be seen to the contrary, they seemed to be the only commanders of the ship; only...
Enter Ahab; to Him, Stubb
Authors: Melville Herman , Blum Hester
Published: February 2023

Some days elapsed, and ice and icebergs all astern, the Pequod now went rolling through the bright Quito spring, which, at sea, almost perpetually reigns on the threshold of the eternal August of the Tropic. The warmly cool, clear, ringing, perfumed, overflowing, redundant days,...
The Specksynder
Authors: Melville Herman , Blum Hester
Published: February 2023

Concerning the officers of the whale-craft, this seems as good a place as any to set down a little domestic peculiarity on ship-board, arising from the existence of the harpooneer class of officers, a class unknown of course in any other marine...
The Whiteness of the Whale
Authors: Melville Herman , Blum Hester
Published: February 2023

What the white whale was to Ahab, has been hinted; what, at times, he was to me, as yet remains unsaid.

Aside from those more obvious considerations touching Moby Dick, which could not but occasionally awaken in any man’s soul some alarm, there was another...
The Chart
Authors: Melville Herman , Blum Hester
Published: February 2023

Had you followed Captain Ahab down into his cabin after the squall that took place on the night succeeding that wild ratification of his purpose with his crew, you would have seen him go to a locker in the transom, and bringing out a...