bluuebunny/crossref_metadata_2025_split huggingface dataset:
Multi-frequency, megawatt-power gyrotron to facilitate a wide range of operations at ITER
Authors: Ikeda Ryosuke , Shinya Takahiro , Yajima Satoru , Nakai Taku , Ohgo Takeru , Tsuneyama Masayuki , Yamazaki Hibiki , Kobayashi Takayuki , Kajiwara Ken 
Published: April 2023

Abstract
High-power (1 MW), long-pulse operations up to 300 s were demonstrated by multi-frequency oscillations at 170 GHz, 137 GHz, and 104 GHz. A multi-frequency gyrotron based on the design of the ITER gyrotron has been developed and studied. By redesigning the built-in mode convertor and internal mirrors of the ITER gyrotron, the internal scattered power of the gyrotron was reduced while maintaining the same output beam size and beam direction for the three frequencies. In addition, the mirrors of a matching optics unit were designed to efficiently couple the RF beam at 170 GHz, 137 GHz, and 104 GHz oscillations to a waveguide 50 mm in diameter, the same size that will be used in ITER. An HE
11 mode content of ∼94% was achieved for the three frequencies. Output powers of 1 MW at 170 GHz and 137 GHz, and 0.9 MW at 104 GHz were demonstrated up to 300 s. These oscillation frequencies can facilitate in a wide range of toroidal magnetic field operations at ITER, including plasma start-up and electron heating and current drive.
Leakage Protection of Low Voltage TN-C System Based on Characteristic Currents Amplitude Ratio
Authors: Sun Rongke , Gong Huichang 
Published: April 2023

Abstract
With the repeated grounding of the PEN line, load fluctuation, and other factors, there is no available leakage protection for the low-voltage TN-C system, which is very dangerous when a leakage fault occurs. And TN-C grounding mode is still widely used, and the reformation is slow. The single-phase leakage fault and load fluctuation characteristics of the TN-C system are analyzed, and a leakage protection method for the TN-C system based on the amplitude ratio of characteristic currents is proposed. This method takes the amplitude of the residual current sudden change as the starting criterion, and constructs the action criterion according to the amplitude ratio of load current sudden change and residual current’s sudden change, so as to realize the discrimination of leakage fault and load fluctuation. The proposed method can overcome the influence of load fluctuation and other factors, suitable for TN-C systems with high sensitivity and reliability. The effectiveness of the protection is verified by simulation.
Bi-directional Optical Flow-based Feature Point Tracking Method
Authors: Jiang Hao , Chen Li , Cang Naimeng , Wang Shuang 
Published: April 2023

Abstract
In order to improve the robustness of the SLAM system based on the optical flow method, we propose a feature point tracking method with a bi-directional optical flow. The method first couples the forward LK optical flow and the reverse LK optical flow. Then, the feature points are screened and tracked by coupling the bidirectional optical flow. If the screened feature points do not reach the set threshold, they can be supplemented with either Fast points or Harris points. The experimental validation of the above method by VINS-Mono with the EuRoC dataset shows that VINS-Mono using this method significantly improves the accuracy of localization without increasing the running time cost compared with the original VINS-Mono.
High-Gain Transmissive Array Antenna with Broadband Cross-Polarisation Isolation
Authors: Zhang Jing , Liang Jiangang , Zhao Xilai , Lou Jing 
Published: April 2023

Abstract
A transmissive metal unit working in the range of 18 GHz-29 GHz is designed in this paper. This is a three-layer metal circular slit unit with promising cross-polarization isolation properties. A planar lens antenna with a center operating frequency of 28 GHz is designed based on the unit utilizing a phase compensation algorithm. The numerical simulation results show that the antenna can improve the gain of the horn antenna from 22.9 dB to 25.6 dB, which can effectively advance the development of 5G communication technology.
Research on Modeling Method for Excitation System of One Million-Kilowatt Unit in Nuclear Power Plant based on Real-Time Digital Simulation System
Authors: Liu Yanchao , Gu Qiubin , Jiang Yanzhuo , Zhai Changying , Ma Hongxing , Jiang Yi , Li Yan 
Published: April 2023

Abstract
The excitation system is an important link between the generator set and the power grid. It is not only the key system to stabilize the operation of the generator set but also an important element related to the network. The accurate modeling and testing of the excitation system clarify and analyze the characteristics of the system. The traditional simulation software can only simulate the excitation system without the ability to test the control device and protection equipment. However, the real-time digital simulation system (RTDS) can realize real-time closed-loop tests of the hardware, which provides a new means for the excitation system analysis. This paper builds a detailed excitation system model of nuclear power units based on RTDS. The under-excitation limitation model is proposed based on the actual test data. Furthermore, the stability of the stator current limitation is improved by adding restriction conditions. Finally, the excitation system model is validated based on the measured data.
Research and Governance of Power Quality of the Distribution Network Based on Large-Scale Distributed PV Access
Authors: Yu Danwen , Zhang Yan , Wang Qingyu , Su Yongzhi 
Published: April 2023

Abstract
The continuously increasing distributed photovoltaic installations have a great impact on power grid operation, which shows a trend of “local to global development and distribution network to the main network extension”. The situation puts forward higher requirements for power grid power balance, reactive power regulation, and power quality control. Based on the measured data of a regional power grid, this paper analyzes the new problems brought by the large-scale access of distributed photovoltaic to the power quality of distribution network from the aspects of voltage deviation, harmonics, three-phase imbalance, voltage fluctuation, low voltage ride through, and reactive power support in detail. Besides, it describes a series of management and control measures that the local government and grid companies can take to reduce the operation risk of the distribution network against these adverse effects. The purpose is to provide technical guidance for exploring the new mode of distributed photovoltaic grid connection service and regulation operation management in the whole county.
Digital surface morphology modeling of rotary ultrasonic auxiliary grinding spiral bevel gear
Authors: Li Xinrui , Han Jiaying , Jiang Yiqi , Shen Yongli 
Published: April 2023

Abstract
Because the tooth surface micromorphology affects the performance of the gear and the finite element analysis and the grinding process of tooth surface through finite element analysis and simulation is complicated and time-consuming, the paper proposed a three-dimensional (3D) ultrasonic assistant grinding (RUAG) geometric simulation method to discover the micromorphology formation mechanism. Based on the motion path of a single grain, the 3D models of gear blank and the grinder was built. It helps to simulate the RUAG process. The morphologies of the simulated tooth surface were compared under conventional grinding (CG) and RUAG, which was consistent with the practice. It is proved that the geometric simulation method intuitively shows the micro dents on the tooth surface under different grinding parameters. The simulation method is helpful to analyze the surface morphology under different RUAG machining parameters and saves the cost and time of the actual production and processing.
AMB-Supported Flywheel Battery for Electric Tractors: Structure Design and Driving Method
Authors: Liu Bo , Hu Yaobing , Lyu Xujun , Fan Wei , Zheng Kan 
Published: April 2023

Abstract
Active magnetic bearing (AMB) supported flywheel energy system, also called flywheel battery, is a mechanical battery storing kinetic energy in a rotating flywheel disk and has appealing features such as high specific power and energy, short time of charging/discharging, no pollution and long life span. In this paper, we apply AMB-supported flywheel battery as a new type of power battery to electric tractors, which absorbs wasted energy when the electric tractor brakes frequently and provide additional driving energy supplement when the electric tractor face an overload start, a sudden load mutations or field work resistance mutations. The structure design of the AMB-supported flywheel battery is introduced, including the axial/radial magnetic bearing, flywheel disk, the rotor and the motor. The driving method of the whole system is also analyzed. This design provides the reliability guarantee for the innovative application of the AMB-supported energy storage flywheel battery in electric tractors.
Structural Design and Analysis of an Adaptive Manipulator
Authors: Peng Yujie , Bai Jialuo , Chen Huadong , Yang Peijie , Mei Hao 
Published: April 2023

Abstract
In view of the fact that the existing special manipulator is difficult to meet the requirements, and the universal full-drive multi-finger dexterous manipulator has the shortcomings of complex control and relatively poor reliability, this paper designs a manipulator with simple structure, few driving components, strong adaptive ability, and flexible, stable and fast grasp of objects of different complex shapes. The adaptive manipulator underdrive finger adopts a bionic design, which is composed of a rotary wrist joint, condylar MP joint, intermediate PIP joint, and terminal DIP joint, mixed transmission with gear and tendon rope, with the interaction ability of outer rigidity and inner flexibility, which can realize adaptive envelope grasping and pinching.
Study on the Reliability of X-ray Detection of Dissimilar Metal Welded Joints
Authors: Wei Daoxiang 
Published: April 2023

Abstract
Different steel welding joints are widely used in special equipment and often bear the role of high temperature and high pressure, and corrosive media. Because dissimilar steel welded joints are prone to residual stress and defects during welding, cracks may occur during use. Due to the tissue structure of heterogeneous steel and austenite, ultrasonic detection and surface detection methods are poor. This paper puts forward the ray detection method, including artificial defects, using the ray detection method. Detection results show that the heterogeneous steel welding joint internal defects and that the ray detection method has a good detection effect.
Implementation and Precision Analysis of Speed Measurement System for Marine Main Engine
Authors: Chen Kai , Huang Guoxiong , Sun Jiangping 
Published: April 2023

Abstract
The rotational speed of the marine engine plays a critical role in navigation. In practical application, speed measurement was carried out with the help of the centralized control system. In most cases, the speed information would be obtained through a dedicated line, and it would be transmitted to a few special areas, such as the pilot house, the captain’s office, and the controlling center. Consequently, the users could not get the speed information in time, which might increase navigation risk. A speed measurement system independent from the centralized control system of the original engine was proposed and detailed designed in this work. In addition, remote access was realized by network environment configuration. Furthermore, measurement precision was analyzed from theory and experiment. The results indicate that the system works well during long-term operation and the accuracy of measurement meets the requirement. Due to its accuracy and convenience in use, the system can also be widely used in other monitoring situations.
A Pseudo-Differential Capacitive MEMS Accelerometer Analog Front-End Design
Authors: Kong Dameng , Duan Quanzhen 
Published: April 2023

Abstract
Based on the current design and application of the chip and the research status at home and abroad, we proposed a silicon micro-accelerometer analog front-end integrated circuit with high resolution and wide capacitance application range by using SMIC 0.18μm CMOS technology. The circuit is composed of a capacitive readout circuit, a demodulator, and a low-pass filter. To detect the weak capacitive signal, the capacitor readout circuit of this paper adopts the continuous-time voltage mode charge amplifier structure and combines with the signal modulation technology and the optimization of the MOS transistor size to achieve low noise and high resolution. With the application of the signal modulation technology, the low-frequency capacitance sensor signal is shifted from 2-12 kHz to high-frequency 800 kHz. The signal modulation technology modulates the low-frequency capacitive sensor signal of 2~12 kHz at the high frequency of 800 kHz, and the signal is converted into voltage through the capacitive readout circuit. The simulation results show that the designed analog front-end circuit can convert the accelerometer capacitance signal with the frequency of 2~12 kHz, the dynamic capacitance peak is 0.108 pF, and the static capacitance is 10 pF into the expected voltage signal. In addition, the output noise can be as low as 556 nV/√Hz in the capacitive frequency range of the accelerometer, which meets the requirement of 2.5 aF capacitive resolution. Therefore, the silicon micro-accelerometer analog front-end circuit designed in this paper has the characteristics of a wide capacitor application range, low noise, and high resolution, and can be widely used.
Research on cumulative effect and diagnosis method of transformer short-circuit impulse
Authors: Duan MingHui , Liu LiQing , Yao Chuang , Feng JunJi , Ma Xiaoguang , Wei JuFang , Zhang He , Ma Hao 
Published: April 2023

Abstract
After transformers suffer from short-circuit impact, their mechanical performance decreases significantly. This article establishes a two-wire vibration model to represent the coupling between forces and mechanics and analyzes the transient vibration signals of a 400 V transformer during 22 short-circuits impact. To illustrate the cumulative effect of short-circuits, the vibration entropy, and energy ratio of the main vibration frequency and half frequency are adopted. The results show that transient vibration signals of transformer in short-circuits contain half frequency components, such as 25 Hz and 75, etc., and with the increase of the number of short-circuits, plastic deformation exists in insulation material, which leads to the loss of winding clamping pressure, the reduction of natural frequency, and the upsurge of parametric resonance. With the increase of short circuits, the vibration entropy and half-frequency energy ratio increase, and the main frequency energy ratio decreases. After winding completely lose the axial stability, the vibration entropy and half frequency ratio decrease, and the main frequency ratio increases. The conclusion is of great significance to the analysis of the cumulative effect of short circuits on power transformers.
Measurement Method for Wall Crack Size Based on Pixel Ratio
Authors: Luo Xiao , Zhu Hao 
Published: April 2023

Abstract
The identification and measurement of building cracks can reduce the harm caused by accidents to people’s lives. Reducing manual work can improve the efficiency of crack inspection and reduce inspection errors. In this paper, (1) Machine vision with high measurement accuracy and fast response speed is used, the crack contour is extracted by OpenCV splicing, segmentation, morphological processing, and wall cracks can be accurately detected. (2) The crack size is calculated using the pixel ratio algorithm, the image pixel ratio is calculated by the reference object method, and the size of the wall crack is measured. (3) The measurement error is small. In comparing the experimental results and manual measurement, the width measurement error rate is the highest, 0.314%, and the height error rate is the highest, 2.9%. (4) Size information can be displayed to prevent the hazard caused by cracks in advance. So, the system has a good wall crack identification and measurement effect, which reduces labor costs.
A New Piecewise-Compensated Bandgap Reference Circuit with a Trimming Procedure
Authors: Wei H Y , Duan Q Z 
Published: April 2023

Abstract
A new CMOS bandgap reference (BGR) circuit with a piecewise-compensation circuit and a trimming network is proposed and designed to obtain a bandgap reference voltage with a low-temperature coefficient and a high precision, taking into account the effect of non-ideal factors on the results. The proposed piecewise compensation circuit is designed to achieve a constant reference voltage by using a current mirror to mirror the current, combined with a subtractive circuit and an additive circuit to obtain a low-temperature coefficient over an extensive temperature range. The trim network part is used to change the voltage value of the output reference by controlling the magnitude of the resistance value of the resistors connected to the circuit. The design and simulation of the proposed bandgap reference circuit are obtained by using Cadence Spectre simulation by SMIC 0.18 μm CMOS technology. The results indicates that when the power is 3.3 V and the temperature scope is within -40 °C to 125 °C, the output voltage is 1.2 V with the temperature coefficient equal to 0.658 ppm/°C. When the power varies within 3.2 V to 3.4 V, the linear regulating rate is 0.001019 %/V.
Numerical studies on rock breaking of single axe-shaped PDC cutter
Authors: Yao Jianlin , Zhang Wei , Liu Bin 
Published: April 2023

Abstract
For a drill bit, the cutter is the most important part to break the rock. In oilwell drilling, polycrystalline diamond compact (PDC) bit is widely used to shear the rock formation. In this paper, a finite element model with including the axe-shaped PDC cutter and rock formation is developed to study the rock breaking behaviours. Results show that the effect of axe-shaped PDC cutter on rock breaking is better than that of the planar PDC cutter. The front rake angle and face angel play significant role on the axial force but have little influence on the tangential force. In addition, both the tangential force and axial force increase rapidly with increasing the depth of cut.
Ground Fault Detection of Small Resistance Grounding System Based on Improved Phase Current Abrupt Variable Method
Authors: Xu Xianze 
Published: April 2023

Abstract
When a high fault resistance happens in a small resistance ground system, the protection device is simple to be unsuccessful to manage. By analyzing the characteristics of positive, negative currents in the additional state of fault, it is found that the fault detection method constructed only by the phase current increment relationship has risk of misoperation, but relationship among the magnitude of phase current increment can directly reflect the phase of the ground fault. At the same time, the phase location among the fault phase voltage and the current of the unhealthy part and non-fault line is different. Therefore, a ground fault protection method based on the correlation between the phase current increment ratio and the different phase angles of fault phase voltage and current is proposed. We choose the phase with the big phase current mutation as the grounding phase, and affect the fault part by the phase difference between the fault phase voltage and the current of the line. This eliminates the risk of protection maloperation only using the relationship between the size of current increment and protection sensitivity in case of high resistance fault. It can be used for fault phase selection, location, and multi-level protection. The correctness of the way is certificated by simulation.
An Improved RGB-D SLAM Method Based on Manhattan World and Point-Line-Plane Features
Authors: Yang Dehua , Pei Hailong , Weng Zhuorong 
Published: April 2023

Abstract
At present, most feature-based SLAM methods are based on feature points. But in indoor environments where texture is scarce and light varies greatly, these methods will reduce the accuracy of pose estimation or even lead to pose tracking failure. To tackle the above problem, we propose an improved RGB-D SLAM method which employs point-line-plane feature extraction and matching as well as Manhattan Frames-based rotation estimation. Finally, the proposed method is proven to have good reliability and robustness in open datasets and real indoor scenes.
Design of Function of Anti-islanding in Novel Power Distribution System with Distributed New Energy Access
Authors: Su Guang , Shi Jinyuan , He Shengli , Han Tao , Su Biaolong , Du Hongwei 
Published: April 2023

Abstract
With the proposal of “Double-Carbon” goal and the acceleration of energy transformation, a large number of distributed new energy sources such as photovoltaics and wind power, are connected to the power distribution system, the power distribution system has developed into a novel distribution system with the optimization and coordination of energy as its core, thus put forward higher requirements for the safety protection of distribution network. However, when the line of distribution network is repaired or faulty, the power distribution system is very easy to cause islanding effect. Measures of anti-islanding are still implemented based on the grid-connected inverter on the user’s side, and there may be dead zones for anti-islanding protection or other abnormal situations. From the perspective of a novel power distribution system, this paper proposes the method of anti-islanding in novel distribution system with distributed new energy access. The identification of islanding criterion signal, the determination of islanding operation’s area, the generation and execution of islanding processing strategy, the evaluation of islanding processing result and the display of anti-islanding function are elaborated in detail. By analyzing the scenarios of actual application of the anti-islanding processing method, the proposed method can accurately sense the state of islanding of the distribution network and quickly isolate the operating area of islanding through remote control, and the novel power distribution system with distributed new energy access can be prevented from running in islanding, which greatly improves the efficiency of anti-islanding processing for dispatchers, so as to ensure the safe, stable and reliable operation of the distribution network.
Dispatching strategy of base station backup power supply considering communication flow variation
Authors: Ouyang Zheyu , Zhang Yanchi 
Published: April 2023

Abstract
With the mass construction of 5G base stations, the backup batteries of base stations remain idle for most of the time. It is necessary to explore these massive 5G base station energy storage response power transmission network scheduling. In this article, the schedulable capacity of the battery at each time is determined according to the dynamic communication flow, and the scheduling strategy of the standby power considering the dynamic change of communication flow is proposed. In addition, the model of a base station standby battery responding grid scheduling is established. The simulation results show that the standby battery scheduling strategy can perform better than the constant battery capacity.