bluuebunny/crossref_metadata_2025_split huggingface dataset:
Study of cathode-spot crater and droplet formation in a vacuum arc
Authors: Wang Lijun , Zhang Xiao , Li Jiagang , Luo Ming , Jia Shenli 
Published: February 2021

AbstractA 3D transient model of a cathode-spot crater and droplet formation in a vacuum arc is developed. The model includes mass, momentum, heat transfer (energy), current continuity and potential equations. Using the energy flux density, current density and pressure as external parameters, the shape of the cathode-spot crater and the temperature, velocity, potential and current density distributions at each time step are determined via numerical simulation. Under symmetrical conditions, the 3D simulation results are highly consistent with those from the previous 2D model. The new cathode spot tends to appear in the direction in which the protrusion is largest because the liquid-metal velocity is lower and the liquid-metal ridge radius is larger in this direction. The effect of the external transverse magnetic field is considered by using a symmetric space function to represent the pressure and energy flux density of the plasma cloud. Simulation results show that even small changes in the plasma cloud distribution have a significant impact on the cathode-spot crater process and droplet formation. Since the pressure is asymmetric, the crater becomes asymmetric and the new cathode spot tends to appear opposite to the direction of the Ampere force. Based on this phenomenon, a possible explanation for the retrograde motion phenomenon of cathode spots is proposed.
Raw GNSS observations from Android smartphones: characteristics and short-baseline RTK positioning performance
Authors: Gao Rui , Xu Li , Zhang Baocheng , Liu Teng 
Published: February 2021

Abstract
The release of raw global navigation satellite system (GNSS) observations by Google Android makes high-precision positioning possible with low-cost smart devices. This study contributes to this research trend by constructing a stochastic model based on raw GNSS observation characteristics from Android smartphones and verifying the feasibility of smartphone-based ambiguity fixing in the short-baseline real-time kinematic (RTK) case. This study uses the raw observation standard deviations (ROSTDs) delivered by the Android application programming interface (API) as a stochastic model and takes advantage of the multipath index from the API to rule out unusable observations. As well as these, the ambiguity integer property is investigated by analyzing the residuals of double-differenced carrier-phase observations associated with one smartphone and one geodetic-grade receiver. Furthermore, we note that the carrier-phase observations collected by tested smartphones do not have the integer property but for the Huawei P30 and Xiaomi 8 devices, such an integer property can be successfully recovered by means of detrending. With the use of ROSTD-dependent weighting, we first perform single-point positioning (SPP) and real-time differentition (RTD) using pseudorange observations delivered by the Huawei P30 and Xiaomi 8 devices. The results show that the stochastic model is applicable to the Xiaomi 8. Moreover, the three-dimensional root-mean-square (3D-RMS) errors of the two smartphones for SPP are 1.28 m and 1.96 m, and the 3D-RMS errors for RTD are 0.79 m and 1.64 m, respectively. We next test the RTK positioning performance based on a short-baseline of 882 m using carrier-phase observations with recovered integer ambiguities. For the Huawei P30, the positioning errors achieved were 7.8, 2.4, 1.1 mm for the east, north, and up (ENU) components at the time of first fix while for the Xiaomi 8, the positioning errors achieved were 4.3, 4.2, 4.2 mm for the ENU components at the time of first fix.
Hollow porous BiOCl microspheres assembled with single layer of nanocrystals: spray solution combustion synthesis and the enhanced photocatalytic properties
Authors: Yang Zhongxiang , Shang Zhichao , Liu Fang , Chen Yirui , Wang Xiaohong , Zhang Bangsheng , Liu Guiqing 
Published: February 2021

Abstract
The hollow porous microspheres assembled with BiOCl nanocrystals were successfully synthesized via a facile spray solution combustion synthesis method. The microstructure, morphology, absorbance, optical properties of the samples were investigated in detail. The results show that hollow porous BiOCl microspheres have narrow band gaps (2.66–2.71 eV), and the degradation rate of rhodamine B (RhB) can reach 98% under visible light irradiation for 60 min. Furthermore, the mechanism of the photocatalytic degradation of RhB was proposed through the experiment of trapping active species. This excellent photocatalytic property can be ascribed to the larger specific surface area and the special microstructure.
Interventional respiratory motion compensation by simultaneous fluoroscopic and nuclear imaging: a phantom study
Authors: Dietze Martijn M A , Kunnen Britt , Lam Marnix G E H , de Jong Hugo W A M 
Published: February 2021

Abstract

Purpose. A compact and mobile hybrid c-arm scanner, capable of simultaneously acquiring nuclear and fluoroscopic projections and SPECT/CBCT, was developed to aid fluoroscopy-guided interventional procedures involving the administration of radionuclides (e.g. hepatic radioembolization). However, as in conventional SPECT/CT, the acquired nuclear images may be deteriorated by patient respiratory motion. We propose to perform compensation for respiratory motion by extracting the motion signal from fluoroscopic projections so that the nuclear counts can be gated into motion bins. The purpose of this study is to quantify the performance of this motion compensation technique with phantom experiments. Methods. Anthropomorphic phantom configurations that are representative of distributions obtained during the pre-treatment procedure of hepatic radioembolization were placed on a stage that translated with three different motion patterns. Fluoroscopic projections and nuclear counts were simultaneously acquired under planar and SPECT/CBCT imaging. The planar projections were visually assessed. The SPECT reconstructions were visually assessed and quantitatively assessed by calculating the activity recovery of the spherical inserts in the phantom. Results. The planar nuclear projections of the translating anthropomorphic phantom were blurry when no motion compensation was applied. With motion compensation, the nuclear projections became representative of the stationary phantom nuclear projection. Similar behavior was observed for the visual quality of SPECT reconstructions. The mean error of the activity recovery in the uncompensated SPECT reconstructions was 15.8% ± 0.9% for stable motion, 11.9% ± 0.9% for small variations, and 11.0% ± 0.9% for large variations. When applying motion compensation, the mean error decreased to 1.8% ± 1.6% for stable motion, 2.2% ± 1.5% for small variations, and 5.2% ± 2.5% for large variations. Conclusion. A compact and mobile hybrid c-arm scanner, capable of simultaneously acquiring nuclear and fluoroscopic projections, can perform compensation for respiratory motion. Such motion compensation results in sharper planar nuclear projections and increases the quantitative accuracy of the SPECT reconstructions.
H2RSPET: a 0.5 mm resolution high-sensitivity small-animal PET scanner, a simulation study
Authors: Lai Youfang , Wang Qian , Zhou Shiwei , Xie Zhaoheng , Qi Jinyi , Cherry Simon R , Jin Mingwu , Chi Yujie , Du Junwei 
Published: February 2021

Abstract
With the goal of developing a total-body small-animal PET system with a high spatial resolution of ∼0.5 mm and a high sensitivity >10% for mouse/rat studies, we simulated four scanners using the graphical processing unit-based Monte Carlo simulation package (gPET) and compared their performance in terms of spatial resolution and sensitivity. We also investigated the effect of depth-of-interaction (DOI) resolution on the spatial resolution. All the scanners are built upon 128 DOI encoding dual-ended readout detectors with lutetium yttrium oxyorthosilicate (LYSO) arrays arranged in 8 detector rings. The solid angle coverages of the four scanners are all ∼0.85 steradians. Each LYSO element has a cross-section of 0.44 × 0.44 mm2 and the pitch size of the LYSO arrays are all 0.5 mm. The four scanners can be divided into two groups: (1) H2RS110-C10 and H2RS110-C20 with 40 × 40 LYSO arrays, a ring diameter of 110 mm and axial length of 167 mm, and (2) H2RS160-C10 and H2RS160-C20 with 60 × 60 LYSO arrays, a diameter of 160 mm and axial length of 254 mm. C10 and C20 denote the crystal thickness of 10 and 20 mm, respectively. The simulation results show that all scanners have a spatial resolution better than 0.5 mm at the center of the field-of-view (FOV). The radial resolution strongly depends on the DOI resolution and radial offset, but not the axial resolution and tangential resolution. Comparing the C10 and C20 designs, the former provides better resolution, especially at positions away from the center of the FOV, whereas the latter has 2× higher sensitivity (∼10% versus ∼20%). This simulation study provides evidence that the 110 mm systems are a good choice for total-body mouse studies at a lower cost, whereas the 160 mm systems are suited for both total-body mouse and rat studies.
Conversion factor for size specific dose estimation of head CT scans based on age, for individuals from 0 up to 18 years old
Authors: Honorio da Silva Edilaine , Baffa Oswaldo , Elias Jorge , Buls Nico 
Published: February 2021

Abstract
Assessing the radiation doses received by patients in computed tomography is still challenging. To overcome this, the American Association of Physicists in Medicine has introduced the concept of the size specific dose estimate (SSDE). However, the calculation of SSDE for head CT scans requires the knowledge of attenuation characteristics of the volume scanned, making its implementation in the daily clinical workflow cumbersome. In this study, we defined conversion coefficients from CTDIvol,16cm to SSDE for head CT scans based solely on the age of the patient. Using the head circumference-for-age from the child growth standards of the World Health Organization (WHO), the effective diameter-for-age was calculated for male and female individuals from 0 to 60 months-old. The effective diameter was converted into a water equivalent diameter-for-age, using a correlation established from the measurements of both quantities in 295 exams of male and female patients, from 0 to 18 years-old. WHO-estimated water equivalent diameter-for-age was validated against the measured water equivalent diameter-for-age. The head circumference-for-age from WHO was extrapolated for male and females individuals up to 18 years-old and their respective water equivalent diameter were estimated. Finally, the SSDE was calculated for all the CT head scans performed in a 9-years period in patients aged from 0 to 18 years old. Typical values of CTDIvol,16cm and DLP were also defined. SSDE varied from 0.80 up to 1.16 of the CTDIvol,16cm, depending on sex and age of the patient. WHO-estimated water equivalent diameter-for-age differed less than 20% from the measured water equivalent diameter-for-age. Typical values of SSDE varied from 28.5 up to 38.9 mGy, while typical values ranged from 30.9 up to 47.6 mGy for the CTDIvol,16cm and from 417.6 up to 861.1 mGy*cm for the DLP. SSDE can be directly calculated for head CT scans once the age of the patient is known.
A Novel Fault Diagnosis Strategy of MMC Battery Energy Storage System Based on SPVD
Authors: Yibin Tao , Shi Yin , Xin Zhan , Guanjun Li , Zhong Liu 
Published: February 2021

Abstract
With the vigorous development of renewable energy, high-power energy storage systems have become a key technology for energy transformation. Electrochemical energy storage systems based on modular multilevel converters have become a hot and difficult research topic due to their modular design, fast dynamic response, and excellent output quality. The MMC-BESS system contains a large number of sub-modules, each of which is a potential fault point. How to quickly diagnose and locate faults is the main research content of this article. First, the mathematical model of MMC-BESS is established, and the observer is constructed to judge whether the system is in a fault state. Second, the changing trend of the fault status of the sub-module is analyzed, and a fault location strategy based on port voltage discrimination is proposed. Finally, the experimental verification of the proposed diagnostic strategy proves the effectiveness and feasibility of the diagnostic strategy.
Compensation of Subdivision Error of Capacitance Encoder Based on Lissajous Graphic Analysis
Authors: Wang Aijia , Ding Hongchang , Hou Han , Li Kun , Zhao Changfu 
Published: February 2021

Abstract
With the development of measurement technology in the direction of precision, high speed, automation, integration, intelligence, economy, non-contact and multifunction, it has simple structure, small size, low energy consumption and strong adaptability. And other advantages have been widely used. However, the sensor of the capacitive encoder works in the state of low voltage and low current, and is extremely susceptible to the influence of the external electric field and magnetic field, causing problems such as input signal distortion and system failure. With the increasing requirements of the manufacturing industry for stability and accuracy, it is of great significance to analyze the capacitive coding error and improve the accuracy. This article analyzes the error generated by the capacitive encoder, enumerates the influence of DC deviation, amplitude deviation, phase deviation, and high-order harmonics on the interpolation error, and compensates the error signal for the aspects that cause larger errors. The sine and cosine signals are close to the ideal state.
An Improved Research on Frequency-Fixed Cascaded SOGI Single-Phase PLL
Authors: Gu Yukun , Jin Ke , Yang Chen 
Published: February 2021

Abstract
The second-order generalized integrator (SOGI) with band-pass filtering characteristics is widely used in the design of advanced single-phase phase-locked loops (PLLs). But this type of PLL has insufficient ability to restrain dc biases, which limits their applications under certain conditions. Recently, a PLL adopting two cascade SOGI structures is called the cascaded generalized integrator PLL (CGI-PLL), which has perfect dc offsets blocking capability. However, the two output signals of the quadrature signal generator (QSG) formed by frequency-fixed CGI have different amplitudes, which makes the second harmonic oscillations appear in the estimated parameters of the PLL while the frequency deviates from the nominal frequency. Similarly, the in-phase output signal of CGI-based QSG is not synchronized with the fundamental frequency component of the grid voltage under frequency drifts, which is the reason for the phase offset error in the PLL outputs in the steady state. Some compensation strategies are added to correct the error that exists in the frequency-fixed CGI-PLL when the frequency deviates from the nominal value.
Wireless strain synchronization acquisition method based on Kalman Filter
Authors: Tang Yu , Dai Yawen 
Published: February 2021

Abstract
For distributed wireless sensor networks, the time synchronization mechanism is the core part and the key to realize the coordination and processing of tasks between nodes. In this paper, an algorithm based on kalman filter is developed the wireless strain of synchronous acquisition system, through the coordinator fixed time interval by a synchronous message, when each node receives the synchronous message to mark its timer timestamp clock information of nodes, then the node according to the records of the clock information periodically call kalman filtering algorithm is used to estimate the next cycle of its own real clock and standard clock deviation coordinator, in the next cycle, real-time compensation is made by adjusting the overflow count value of node timer to achieve high synchronization accuracy. The sensor nodes in the system have high strain sampling accuracy and meet the requirements of general engineering applications.
Research on Model Predictive Control Based on Sensorless Permanent Magnet Synchronous Motor
Authors: Fan Shengwen , Zhang Xinsen , Tong Chaonan 
Published: February 2021

Abstract
For permanent magnet synchronous motor (PMSM) speed control system, aiming at the problems of slow dynamic response and large dependence on system model parameters of traditional PI control of PMSM, the model predictive current control strategy is adopted to design the predictive model. Aiming at the problems of poor reliability and high cost of traditional permanent magnet synchronous motor with mechanical sensor, the speed sensorless control technology is introduced to design the control structure, and the rotor position and speed are estimated by sliding mode observer method. Through simulation verification, the results show that the combination of the above two control methods can obviously improve the performance of the traditional permanent magnet synchronous motor control system, and has strong robustness under the conditions of motor parameters and load changes.
Improved two-vector model predictive torque control for PMSM
Authors: Sun Chaojun , Liu Shuxi , chen Lan 
Published: February 2021

Abstract
Aiming at the problems of the traditional model predictive control (MPTC) of permanent magnet synchronous motor (PMSM) that the weight coefficient setting is cumbersome and the torque and flux pulsation are large, an improved PMSM two-vector model is proposed to predict the torque. This method expands the virtual vector to increase the voltage candidate vector, combines the voltage vector to act on the torque and flux linkage principle, selects the voltage vector, and reduces the calculation amount of the candidate vector. The evaluation mechanism of the selected vector is set by combined with the duty cycle method, so the weight factor of cost function in the traditional method is eliminated. The simulation results show that the improved method proposed can not only maintain high dynamic performance, but also improve the control effect of torque and flux linkage in the steady state of the system.
The power-delay product and its implication to CMOS Inverter
Authors: Han Zitong 
Published: February 2021

Abstract
Due to power dissipation has always been a significant standard for low power VLSI design, as a parameter that could reflect both circuit power consumption and delay, Power-Delay Product is of great research value. This paper mainly explores the working principle of CMOS inverter, and the definition, and formation causes of PDP. Two experiments were designed based on LTspice for investigating the effect of width to length ratio of the channel of transistors and the stack approach on the propagation delay and dynamic dissipation of CMOS inverter. It is verified that the propagation delay of the inverter is just related to the ratio of the width of the channel between NMOS and PMOS transistors. It is also verified that the range of ratios of the width of the channel between two transistors which makes the propagation delay and PDP minimum is 2∼4, and the stack approach could reduce the PDP in the CMOS inverter effectively.
Construction and Application Research of Knowledge Graph in Spacecraft Launch
Authors: Chao Kou , Tao Liu , Li Ma , Guoyu Jiang , yuchao Wang , Yu Zhao 
Published: February 2021

Abstract
In this paper, through analyzing the necessity of constructing a knowledge graph in spacecraft launch, we construct and use a knowledge graph in spacecraft launch, which serves as not only an effective way of solving the problem of "sparse knowledge" and "incomplete knowledge" in a sea of data but also a basis for achieving Semantic Artificial Intelligence (Semantic AI) and complex data analytics and applications. On the basis of understanding the basic technical architecture of knowledge graph, this paper analyzes the construction approaches of the knowledge graph in spacecraft launch in terms of knowledge source, modeling, extraction, fusion, inference, and storage. By means of the knowledge graph, automatic question-answering based on semantic search, fault detection based on machine learning, and portraits of equipment or information system can be achieved at the launch site. In doing so, the intelligent data engineering and construction at the launch site can be improved.
Research on sales Forecast based on XGBoost-LSTM algorithm Model
Authors: Wei He , Zeng QingTao 
Published: February 2021

Abstract
Reasonable sales forecast is very important for enterprises. The short-term and long-term sales changes of a product are helpful for enterprises to make marketing strategies and sales decisions. On the basis of in-depth analysis of the characteristics of a certain algorithm model and long and short memory neural network, and according to the data set provided by a supermarket chain in kaggle competition, a XGBoost-LSTM neural network combination model for sales forecasting and a classical time series prediction model are constructed to compare the experimental results. The experimental results show that the XGBoost-LSTM neural network prediction model has higher accuracy than the time series prediction model, which can provide an important scientific basis for the supermarket chain to make sales forecast.
Design of an Adaptive Sidelobe Cancellation Algorithm for Radar
Authors: Hong Tian 
Published: February 2021

Abstract
In complex electromagnetic interference environments, adaptive sidelobe cancellation is an effective measure to suppress radar active jamming. It adopts spatial filtering technology, which can effectively suppress sidelobe interference[1]. In this paper, the basic theory of adaptive sidelobe cancellation system is introduced, and two commonly used algorithms are briefly introduced. In practical application, the cancellation effect decreases due to many factors. In order to improve the performance of adaptive sidelobe cancellation, this paper proposes a method of adaptive acquisition of interference sampling data, and uses this method to simulate and analyze the collected jamming data. Now the device function is becoming more and more powerful, and the system hardware platform has also developed rapidly. Compared with the traditional method, this new interference data sampling method has certain advantages and is of practical significance. At the same time, the problems that should be paid attention to in engineering implementation are put forward.
Assessment of the passenger aircraft mass and efficiency with a fuselage without portholes
Authors: Menouni Abderrafie El , Kretov Anatolii , Zhijin Wang 
Published: February 2021

Abstract
The problem of evaluating the effectiveness of reducing the weight of the aircraft and, in particular, the use of the concept of “fuel efficiency” is considered. For the design (operational) mass analysis, the mass state equation is used, on the basis of which the method of mass growth coefficients is constructed. The most widely used short-haul and medium-haul passenger aircraft of the B737 and A320 types are considered as an example of the application of this technique. The authors suggest to reduce the weight of the aircraft structure to switch to the fuselage without portholes. In the present work, this decision is assessed from the point of view of saving fuel weight.