bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical radiation dosimetry in magnetic fields: characterization of a Fricke-type chemical detector in 6 MV photon beams and magnetic fields up to 1.42 T
Authors: Trachsel Maria A , Pojtinger Stefan , Meier Markus , Schrader Markus , Kapsch Ralf-Peter , Kottler Christian 
Published: February 2020

Abstract
In magnetic resonance guided radiotherapy (MRgRT) radiation dose measurements needs to be performed in the presence of a magnetic field. In this study, the influence of magnetic fields on the readings of a Fricke detector, a chemical dosimeter, have been investigated in 6 MV photon beams. This type of detector has been chosen, as the Federal Office of Metrology (METAS, Switzerland) has great experience with Fricke dosimetry and since it is not expected that this detector is greatly affected by the presence of a magnetic field.
Magnetic fields with field strengths between 0 T and 1.42 T were applied during the detector irradiation. In a 5  ×  10 cm2 irradiation field, the Fricke readings are affected less than 0.9% by the applied magnetic fields. Taking the altered dose distribution due to the magnetic field (

) into account, the magnetic field correction factors (

) for the Fricke detector at 0.35 T and 1.42 T are determined to be 0.9948 and 0.9980, respectively. These small corrections hardly exceed the measurement uncertainties. Hence, we could proof that the Fricke detector is not significantly influenced by the presence of a magnetic field.
The Fricke detector was also tested for the feasibility of measuring output factors in the presence of magnetic fields. For irradiation field sizes larger than the detector (>2  ×  2 cm2), comparable results were obtained as for other detectors. The output factors decrease when a magnetic field is applied. This effect is more pronounce for larger magnetic field strengths and smaller irradiation fields due to shifts of the depth dose curves and asymmetry of lateral dose profiles.
Research on hierarchical differentiation intelligent examination method for operational health of low voltage distribution network
Authors: Han Haian 
Published: February 2020

Abstract
The operational health assessment of the Low-voltage Electricity District is the basic task of grid and refined management of low-voltage distribution network. Considering of the large number of stations and the lack of standardized management constraints, using the big data platform and multi-source heterogeneous data management technology, a kind of intelligent medical check-up method for the health of district station is proposed. Firstly, the self-organizing neural network clustering technology is used to classify the station area into 15 categories, which must take into account of geographical attributes, economic attributes and so on. Then, for each major type of area, the analytic hierarchy process is used to realize the subjective weight of the differentiated subject indicators. The entropy weight method is used to realize the objective weight of the three-level subdivision index, and the distance map method is used to realize the percentile mapping of the three-level subdivision index. Finally, the subjective and objective comprehensive weights are given to get the running health score of the station. Based on the actual platform data of a power supply unit in Shan Xi Province, the accuracy of the confusion matrix of the health classification of the station is about 92%, which verifies the effectiveness and applicability of the method.
Research on fault feature extraction method of rolling bearing based on improved wavelet threshold and CEEMD
Authors: Yang Lixiang , Hu Qinghe , Zhang Shuang 
Published: February 2020

Abstract
Because bearing fault feature information is not easy to extract in noisy background, this paper proposes an improved rolling bearing fault feature extraction method based on combination of wavelet threshold and complementary ensemble empirical mode decomposition (CEEMD). Firstly, the improved wavelet threshold denoising method is used to reduce the noise of the vibration signal, and the impact characteristics in the signal are enhanced. Then, the CEEMD decomposition is used to obtain a set of Intrinsic Modal Functions (IMFs), and IMFs with larger kurtosis and correlation coefficients are selected for signal reconstruction. At last, the envelope spectrum analysis of reconstructed signal is carried out to extract fault characteristic information. Through the experimental analysis of the vibration signals of the outer ring and inner ring of the rolling bearing, it is proved that this method can effectively extract the fault characteristics of the bearing.
The Equivalent Relationship between Space Vector and Carrier-based PWM Modulation Strategy in Current Source five-level Inverters
Authors: Cheng Ruiqi , He Yingjie , Deng Qinrui , Wang Yue , Guo Haoting 
Published: February 2020

Abstract
In order to achieve equivalent modulation of the three-phase five-level current source converter, this paper, based on the topology of three-phase five-level current-source converter, proposes a new method to realize the output characteristic of SVPWM with CBPWM, and this method can be applied in any space vector modulation sector of the topology. Different from the strategies of traditional unity theory, the proposed method decomposes the modulated waves directly according to the switching states of SVPWM in five-level current source converters and compare the sub-modulation waves with two inverting carriers. Finally, a simulation on MATLAB is carried out to verify the correction of the method.
Design and Optimization of Magnetic Coupled Resonant Wireless Power Transfer System at Weak - coupling Region
Authors: Song Dawei , Shi Fengdong , Liu Wei 
Published: February 2020

Abstract
Frequency splitting is one of the hot topics in the research of magnetic coupling wireless power transfer technology. Its purpose is to improve the transmission efficiency by eliminating the frequency splitting at the over-coupled region of the system. Frequency splitting does not occur at the weak coupling region. The transmission characteristics of the system in weak-coupled region are also of research significance. The mathematical model of the system’s transmission characteristic was established by equivalent circuit theory. Several key factors that affect the transmission characteristics of the system, self-inductance of the coil, mutual inductance between the coils, load resistance and so on, were obtained. A magnetically coupled resonant wireless power transfer system is designed and A method of coil design is proposed. The transmission efficiency of the system at the weak-coupling region was improved by optimized the design of the coil. Simulation and experimental results had good consistency. The results show that the transmission performance of the system at the weak-coupling area was improved.
Fiber optic gyro signal denoising based on variational mode decomposition and adaptive noise cancellation
Authors: Huang Chunfu , Li An , Qin Fangjun , Wang Zhi 
Published: February 2020

Abstract
The output signal of the fiber optic gyro (FOG) often contains a large amount of noise, which makes it difficult to model and calibrate. Therefore, it must be denoised. In this paper, an adaptive noise cancellation method based on variational mode decomposition (VMD) is proposed. The FOG signal was decomposed into a series of mode components with different center frequencies, and the correlation coefficient method was used to determine the number of decomposition layer. The low-frequency signal and the high-frequency noise components were distinguished by the frequency distribution of each component. They were respectively accumulated to use as the ready denoising signal and the reference noise, then obtaining the denoised signal by adaptive noise cancellation. Using FOG measured data, the proposed method was taken into experiment compared with traditional methods. Allan variance analysis verified that the proposed method effectively suppresses the noise in the FOG signal.
Selection Method of Test Pulse Width and Amplitude to Avoid Self-heating Effect of Power Devices
Authors: Li Jinyuan , Wei Lei , Li Yaosheng , Guo Chunsheng 
Published: February 2020

Abstract
The objective of this study was to address the deviation of electrical parameters, which is caused by the self-temperature rise effect of power devices in electrical testing processes. The pulse width and amplitude of the device test were considered as the research object. The three-dimensional variation of the power, junction temperature, and pulse width of semiconductor power devices were investigated using the principle of electrical temperature measurement, and the three-dimensional variation surfaces of the power, junction temperature, and pulse width were established. A method for selecting the pulse width and amplitude of the test to avoid the self-temperature rise of the power device is proposed. This method uses cutting projection to obtain the characteristic curve of the pulse width and power change, and selects an appropriate two-dimensional region of the pulse width and power to avoid the self-temperature rise of the power device. Moreover, the proposed method can be used as a reference when selecting a pulse test method.
Charging Strategy of Supercapacitor in Photovoltaic Power Generation System
Authors: Guo Kunli , Dong Yan , Fu Jianzhe 
Published: February 2020

Abstract
The charging efficiency of supercapacitor under different charging methods is analyzed by using the improved RC model of supercapacitor. A photovoltaic cell charging system for supercapacitor based on Boost cascade Buck converter (BOCBB) is proposed. The former Boost converter is connected to the photovoltaic power generation system, and the conductance increment method is used to track the maximum power point of the photovoltaic cell. The latter Buck converter uses a segmented charging strategy to charge the supercapacitor. Based on this circuit, a complete control method for the supercapacitor charging system is proposed. Finally, the charging efficiency of supercapacitor by photovoltaic cells under different lighting conditions is simulated and analyzed.
Design of a Broadband LNA with Multi-feedback Using 70nm GaAs MHEMT Process
Authors: Guan Jin , Gong Min , Gao Bo , Zhang Ran 
Published: February 2020

Abstract
This paper presents a broadband LNA using 70nm GaAs MHEMT process operating from 1.5GHz to 20GHz. The multi-feedback technique and input/output impedance match are applied to compensate the transistor gain roll-off with frequency and optimize the stability and reflection coefficients. The effect of the multi-feedback technique for stability, noise figure, gain flatness, linearity, and S-parameter performance are analyzed and discussed. Among the whole bandwidth, this LNA features gain of average 29.5dB increasing with frequency and noise figure of average 1.15dB. This LNA also achieves good reflection and isolation performance. The consuming of this LNA is blow 150mW and the chip area is less than 1.4mm*0.8mm. The figure-of-merit (FOM) is about 362.6 (GHz/mW). This LNA could be found its application in high data rate transmission, software defined radio, 5G communication, test instrumentation, wideband radar and other wideband systems.
Research on Electric Micro-Meteorological Monitoring and Early Warning System
Authors: Zhang Zehao , Yu Zhen , Xu Xiyuan , Guan Cheng , Zhang Song 
Published: February 2020

Abstract
This paper studies and analyzes the influence of micro-meteorological disasters on power system, points out the main problems in the establishment of power micro-meteorological monitoring and early warning system, puts forward the system architecture of power micro-meteorological monitoring and early warning system, which provides a reference for the establishment of power micro-meteorological monitoring and early warning system.
Electric Field Signal Recognition Method of DS Switching Operations Based on Wavelet Packet Analysis and PSO-HSVM
Authors: Yi Tongqiang , Xie Yanzhao , Zhang Hongye , Liu Henan 
Published: February 2020

Abstract
In order to monitor the state of Gas Insulated Substation (GIS), this paper established a fault simulation experimental platform for Disconnecting Switch (DS), and collected data through a 3D radiation electric field (E-field) measurement system. For extract the feature parameters, four-layer wavelet packet decomposition was performed on the data to obtain normalized energy, and the dimension of the eigenvector was reduced by principal component analysis (PCA) algorithm. Then, the model was trained with the hybrid kernel support vector machine (HSVM) algorithm, and the parameters was optimized with the particle swarm optimization(PSO) algorithm. The result shows that compared with the traditional SVM model, the method proposed in this paper improves the diagnosis accuracy of DS defect signals.
Analytical Results to Fuel-optimal Spacecraft Formation Maneuver
Authors: Wang Nan , Gong Deren , Xu Guangtan , Duan Dengping 
Published: February 2020

Abstract
In this study, analytical results are obtained for fuel-optimal spacecraft formation maneuver, including initialization and reconfiguration. The method consists of two stages. The first is parameterization of the problem and a new form of the problem is developed for simplicity. Second, the out-of-plane and in-plane maneuver are studied with the help of a useful inequality introduced and proved, the lower bound of the fuel consumption and the corresponding constraints of the control forces are derived and obtained. The result shows that the minimum total fuel consumption depends on the relative size parameters, and that the existence of optimal control algorithms depends upon the initial conditions. Numerical simulation of application proved the validity and efficiency of the proposed method, which can also be utilized in the maneuver of PCF.
Analysis on the influence factors of operational test effectiveness
Authors: Bo Yun , Bai Hongbo , Wei Guojun 
Published: February 2020

Abstract
Operational test is the concrete embodiment of actual combat guidance in the field of weapon equipment test and evaluation. Based on the analysis of the operational test process, this paper summarizes the operational test requirements and components. Based on the interaction between them, 18 factors of 5 categories affecting the effectiveness of operational tests were analysed, provides a reference for promoting the follow-up operational test to be carried out more scientifically.
Research on the Source-Load Interactive Scheduling Strategy for Modern Industrial Parks
Authors: Haibo Tan , Kai Li , Mouhai Liu , Haiyuan Wang , Cong Tan , Zhiguo Liu 
Published: February 2020

Abstract
Aiming at the problems of diversified demand for electricity, high rate of load growth, limited distribution network corridor and single power supply mode in industrial parks, this paper explores a new scheduling strategy, studies a mechanism of source-load interactive scheduling for modern industrial parks, and puts forward three scheduling strategies, namely, optimal electricity price, friendly power grid and enhanced production. The strategy has been applied in a smart industrial park of Hunan Power Grid. The application results show that the method can effectively improve the power supply capacity of the modern industrial parks, reduce the total cost of electricity, and enhance the load rate of distribution transformers, and it also has high economic and practical value.
A Fast-transient NMOS Capacitor-less LDO with Spike Voltage Sampling Amplifier and Transient Enhancement
Authors: Li Yun , Huang Shengming , Duan Quanzhen 
Published: February 2020

Abstract
A fully-integrated NMOS low dropout voltage (LDO) with spike voltage sampling amplifier is proposed in this paper to provide a stable power supply for many portable devices and artificial intelligence systems. The proposed Spike Voltage Sampling Amplifier circuit is composed of an error amplifier based on dynamic bias of output voltage and a capacitive coupling network, which is embedded in the circuit to detect fluctuations in the output voltage to increase the slew rate of the power transistor so that it turns on and off quickly. The LDO is implemented in 0.18 um CMOS process, which consumes 84uA quiescent current. It regulates output at 1.6V, with dropout voltage of 200 mV. For load current transients from light load 100 uA to heavy load 20 mA at the 100 ns edge-time, the undershoot of the LDO is 82 mV and the recovery time is 167 ns. Similarly, the load current transient from heavy load to light load produces an overshoot of 67 mV and recovery time is 156 ns.
Summary of web crawler technology research
Authors: Yu Linxuan , Li Yeli , Zeng Qingtao , Sun Yanxiong , Bian Yuning , He Wei 
Published: February 2020

Abstract
With the continuous development of network information technology, there is a large amount of unstructured data called big data on the network. Human resources to collect information laborious, so web crawler technology came into being. This paper explores the basic principle and characteristics of web crawler and the classification of current popular crawler, introduces the key technology of crawler, compares two search strategies and the current application of crawler. Finally, the future research direction of web crawler is introduced.
Research on Early Warning of Power Grid Construction Safety Based on PSO-SVM Model
Authors: Sun Yuwei , Zhu Jianbao , Yu Xinchun , Ye Chao , Fan Guoxiang 
Published: February 2020

Abstract
Electric power system is an important symbol of China’s economic development, and electric power construction is an important way of electric power system. However, the potential safety hazards and safety accidents generated during its development have a great impact on economic and social development. In order to reduce the occurrence rate of such accidents, this paper proposes a power grid construction safety early warning model based on PSO-SVM. The quantitative model adopted by the traditional SVM safety early warning method has limitations in parameter optimization. The particle swarm optimization (PSO) algorithm is superior to the traditional method in parameter optimization because it cannot obtain better early warning effect. It uses the information sharing between the whole group and the mutual cooperation between individuals to search, thus searching for better parameter combination and achieving better early warning effect. Finally, the traditional SVM model test for power grid construction is compared, further proving the improvement of the model after improvement.
Research and Application of Integrated Energy Coordination Optimization Control in Distribution Network
Authors: Qi Wang , Hu Hao , Li Hui 
Published: February 2020

Abstract
In recent years, China’s new energy industry has developed rapidly, and photovoltaic and wind power installed capacity has ranked first in the world. However, at the same time of rapid development of new energy sources, the problem of consumption has become increasingly prominent, and the phenomenon of abandoning wind and abandoning light is serious. This paper will start from the power generation principle of distributed power supply and the charge and discharge mechanism of energy storage. Through the analysis of the characteristics of distributed power supply, the new energy consumption is the most, the thermal power input is the minimum, and the distributed power supply is established. The cooperative optimization model of distribution network is constructed, and the coordinated optimization control model based on distribution network automation technology is constructed, and the experimental simulation is carried out to obtain the optimal coordinated energy optimization control model for distribution network to realize the safety, high efficiency and high degree of regional distribution network.
Environmental protection analysis of thermal power units operating under unconventional conditions
Authors: Wang Shunjiang , Ge Weichun , Wei Mofan , Zhang Wuyang , Cao Lina , Lv Xuming 
Published: February 2020

Abstract
Aiming at the problem of optimal distribution of dust removal, desulfurization and denitrification load in thermal power plants, considering the cost of environmental protection, from the perspective of improving the comprehensive economic benefits of the whole plant, the relationship between coal consumption and power generation of the unit is described by using quadratic polynomial. Based on this model, it can be obtained. The unit corresponds to the fuel cost of different power. Considering the cost of environmental protection, the cubic polynomial is used to model the relationship between the pollutant concentration of the unit and the power generation of the unit. The total cost of peak shaving of the unit is calculated by the unit price of pollutant emissions in different periods. In addition, considering the efficiency of desulfurization and denitrification when the unit is operated under low load conditions, the concentration of pollutants in the exhaust gas is increased, which causes additional environmental costs of government fines, and a model of additional cost is proposed. Based on the actual operating data of the unit, a model for optimal comprehensive economic benefit was established and the constraints were established. And verify the correctness of the model.
Level Set for Semantic Segmentation with Edge Compensation
Authors: Lei Zhipeng , Zheng Wei , Miao Yongxin , Fei Xuan 
Published: February 2020

Abstract
This paper demonstrated that active contour based on points evolution is not suitable for Objects with blurring boundary segmentation. In irregular areas adjacent points have similar motion trends trapped into ‘piles phenomena’. Level set should be preferred in practice. Whereas, classic level set lacks of perception in distance especially narrow and abnormal region. Consequently, we reported an algorithm localized level set that is able to improve accuracy. Meanwhile, in cases lost boundary of bone, we gave a strategy called edge compensation. Depending on shapes of neighborhood slices, defective section is estimated and restored effectively. Our experiments showed that the algorithm localized level set increases segmental quality with precision 99.74%. Additionally, it could not only rectify mistakes brought by incorrect initialization but also have a robust performance to overcome local region with highly inhomogeneous intensity.
Research on Clock Source Correction Method based on Wireless Sensor Network and TPSN Network Protocol
Authors: Cui Jisheng , Liu Yunsong , Wei Kai , Cao Hanwen 
Published: February 2020

Abstract
By analyzing TPSN synchronization protocol and various uncertain factors, this paper summarizes the concept of wireless sensor network and the research status of clock synchronization technology in wireless sensor network. To solve the problem that TPSN did not estimate the clock frequency drift, a new idea of wireless sensor network development is proposed: the node local clock self-correction method. The average clock deviation index is designed to evaluate the clock accuracy in a synchronous period. The experimental results show that this method is easy to implement. The synchronization period can be extended, the synchronization cost can be reduced and the energy consumption can be saved.