bluuebunny/crossref_metadata_2025 huggingface dataset:
MC study for TALE Hybrid detector
Authors: Fujita K. , Fujiwara R. , Ogio S. , Tanoue Y.
Published: May 2021

The Telescope Array Low-energy Extension (TALE) Experiment is a hybrid air shower detector for observation of air showers induced by very high energy cosmic rays above 1016 eV. The TALE detector consists of a Fluorescence Detector (FD) station with ten FD telescopes and a surface detector (SD) array made up of 80 scintillation detectors. The TALE-FD and the TALE-SD array have been operational since 2013 and 2017 respectively. A triggering system of the TALE-SD using external triggering signals from the TALE-FD that is of a lower energy threshold, so called the hybrid trigger system, has been working since 2018. We evaluated the performance of hybrid mode of the TALE detector by using Monte Carlo simulation. Here we show analysis method for air shower events observed by the TALE hybrid detector and report the accuracies of air shower parameters.
The Status of AMoRE Double Beta Decay experiment
Authors: Seo Kyungmin
Published: May 2021

AMoRE (Advanced Mo-based Rare process Experiment) is searching for neutrinoless double beta decay of 100Mo. A pilot experiment, AMoRE-Pilot, was operated with six 48dep1Ca100MoO4 crystals of total mass ~1.9 kg in a cryostat at the Yangyang underground laboratory (Y2L) with the minimum overburden of 700 m. Since AMoRE-Pilot started in August 2015, two major improvements in its configuration took place to reduce its background level. The first one was replacement of detector components by materials with lower radioactivity level. The second one was the installation polyethylene blocks together with borated rubber sheets to reduce external neutron backgrounds. Using the AMoRE-Pilot data in different configurations, background modelling of the AMoRE-Pilot was performed.
WATCHMAN: A Remote Reactor Monitor and Advanced Instrumentation Testbed
Authors: Grant Christopher
Published: May 2021

The remote detection of undeclared nuclear reactors, which could be used for production of material used to make nuclear weapons, is a key goal for global nuclear security. To address this challenge, WATCHMAN is beginning construction in Boulby Underground Laboratory, in the UK. WATCHMAN aims to demonstrate the ability to monitor nuclear reactors at distances of tens of kilometers or farther, called far-field monitoring. The first phase of the experiment will consist of a kiloton-scale gadolinium-doped water Cherenkov detector to detect anti-neutrinos coming from the Hartlepool Nuclear Power Station, located at a distance of 25 km from Boulby. The predicted dwell time required for determining that one reactor core is turning on-and-off in the presence of another reactor core is about 10 months. In addition to reactor monitoring, WATCHMAN will also act as an Advanced Instrumentation Testbed for next-generation neutrino detectors.
The measurement of gamma rays from neutron-oxygen interactions
Authors: Horai T.
Published: May 2021

Neutrino neutral-current elastic interaction by atmospheric neutrinos is one of the main background in Supernova relic neutrino (SRN) search at Super-Kamiokande with Gadolinium. Understanding of gamma-ray production via neutron interaction on oxygen is important for the study of neutrino neutral-current elastic interactions. A measurement of gamma-rays production from such reactions was performed by using a 30 MeV quasi-mono energetic neutron beam in the Research Center for Nuclear Physics, Osaka University. In this proceedings the current status and future prospects of this mesurement are presented.
A Bayesian Approach to Neutrinoless Double Beta Decay Analysis in KamLAND-Zen
Authors: Li Aobo
Published: May 2021

Neutrinoless double beta decay (0vββ) is one of the major research interests in neutrino physics. The discovery of 0vββ would answer persistent puzzles in the standard model. KamLAND-Zen experiment is one of the leading efforts in the search for 0vββ. Since January 2019, data was collected using 745 kg of 136Xe and a frequentist likelihood analysis was used to set a limit on 0vββ half-life. In addition to the well-established frequentist approach, we conduct a Bayesian analysis with a Markov Chain Monte Carlo (MCMC). The Bayesian approach allows us to use modern statistical tools and serves as a cross check of the frequentist analysis. Furthermore, we provide the possibility of adding machine learning event classification algorithm to increase sensitivity.
Updated geoneutrino measurement with Borexino
Authors: Ludhova Livia , Agostini M. , Altenmüller K. , Appel S. , Atroshchenko V. , Bagdasarian Z. , Basilico D. , Bellini G. , Benziger J. , Bick D. , Bonfini G. , Bravo D. , Caccianiga B. , Calaprice F. , Caminata A. , Cappelli L. , Cavalcante P. , Cavanna F. , Chepurnov A. , Choi K. , D’Angelo D. , Davini S. , Derbin A. , Di Giacinto A. , Di Marcello V. , Ding X.F. , Di Ludovico A. , Di Noto L. , Drachnev I. , Fiorentini G. , Formozov A. , Franco D. , Gabriele F. , Galbiati C. , Gschwender M. , Ghiano C. , Giammarchi M. , Goretti A. , Gromov M. , Guffanti D. , Hagner C. , Hungerford E. , Ianni Aldo , Ianni Andrea , Jany A. , Jeschke D. , Kumaran S. , Kobychev V. , Korga G. , Lachenmaier T. , Lasserre T. , Laubenstein M. , Litvinovich E. , Lombardi P. , Lomskaya I. , Ludhova L. , Lukyanchenko G. , Lukyanchenko L. , Machulin I. , Mantovani F. , Manuzio G. , Marcocci S. , Maricic J. , Martyn J. , Meroni E. , Meyer M. , Miramonti L. , Misiaszek M. , Montuschi M. , Muratova V. , Neumair B. , Nieslony M. , Oberauer L. , Onillon A. , Orekhov V. , Ortica F. , Pallavicini M. , Papp L. , Penek Ö. , Pietrofaccia L. , Pilipenko N. , Pocar A. , Raikov G. , Ranalli M.T. , Ranucci G. , Razeto A. , Re A. , Redchuk M. , Ricci B. , Romani A. , Rossi N. , Rottenanger S. , Schöinert S. , Semenov D. , Skorokhvatov M. , Smirnov O. , Sotnikov A. , Strati V. , Suvorov Y. , Tartaglia R. , Testera G. , Thurn J. , Unzhakov E. , Vishneva A. , Vivier M. , Vogelaar R.B. , von Feilitzsch F. , Wojcik M. , Wurm M. , Zaimidoroga O. , Zavatarelli S. , Zuber K. , Zuzel G.
Published: May 2021

Borexino is a 280-ton liquid scintillator detector located at the Laboratori Nazionali del Gran Sasso (LNGS), Italy and is one of the two detectors that has measured geoneutrinos so far. The unprecedented radio-purity of the scintillator, the shielding with highly purified water, and the placement of the detector at a 3800 m w.e. depth have resulted in very low background levels and has made Borexino an excellent apparatus for geoneutrino measurements. The new update of the Borexino geoneutrino measurement, using the data obtained from December 2007 to April 2019, has been presented. Enhanced analysis techniques, adopted in this measurement, have been also presented (poster presentation #39 by S. Kumaran). The updated statistics and the new elaborate analysis have led to more than a factor two increase in exposure ((1.12 ± 0.05) × 1032 protons × yr) when compared to the latest Borexino result from 2015. The resulting geoneutrino signal of

47.0

−
7.7

+
8.4

(
stat
)

−
1.9

+
2.4

(
sys
)

TNU has

−
17.2

+
18.3

%

total precision. The geological interpretations of this measurement have been discussed. In particular, the 99% C.L. observation of the mantle signal by exploiting the relatively well-known lithospheric contribution, the estimation of the radiogenic heat, as well as the comparison of these results to the predictions based on different geological models. The upper limits on the power of a hypothetical georeactor that might be present at different locations inside the Earth have been set.
Fast Sampling and Read-Out for Ground-Based Imaging Cherenkov Telescopes
Authors: Bitossi M.
Published: May 2021

The SCT telescope has been proposed as a medium-sized telescope for the Cherenkov Telescope Array. One of the major upgrades is the design of the new Front End Electronics Module (FEEM). New FEEMs aim to read-out and digitize the SiPM pre-amplified signals down to the single photoelectron (phe). This phe signal is assumed equivalent to a signal with 2 mV peak amplitude and 500 MHz maximum bandwidth. FEEM should have a linear response up to 2 V for a required dynamic range of 1000 phe. FEEM noise equivalent of 0.5 phe - 1 mV of RMS noise - is an acceptable value. Due to the severe mechanical constraints, and to have a very compact electronics and low noise performance, FEEM consists of two stacked-up submodules, one dedicated to the power supplies and the other to house the FPGA, which reads out and sends digitized data to the main backplane. An FEEM is capable of digitizing 64 analog channels with a sampling frequency of 1 GSamples/s.
Development of low background PMT R13111
Authors: Abe K.
Published: May 2021

Photomultiplier tubes (PMTs) are one of the largest background sources for many direct dark matter search experiments. The development of a new low background PMT, Hamamatsu R13111, for liquid xenon dark matter experiments is ongoing. With its 3-inch-wide convex protruding photocathode, the R13111 achieved a large reduction in radioactive impurity compared to its precursor, the R10789, which was used in the XMASS-I detector. Xenon leaks, a problem reported by the XENON1T and PandaX experiments, are also investigated to realize stable operation with liquid xenon.
A measurement of the scintillation decay time constant in liquid xenon with the XMASS-I detector
Authors: Ichimura K.
Published: May 2021

The scintillation decay time constant in liquid xenon was measured using the XMASS-I detector and its calibration setup. The scintillation decay time constants of both electron recoil and nuclear recoil were evaluated by comparing the observed photon detection times with Monte Carlo simulations. Two exponential components, corresponding to the singlet and triplet state of the xenon excited dimer, are needed to reproduce the observed photon detection times. In this paper, we report the measurement of the electron recoil and the nuclear recoil scintillation decay time constants with the XMASS-I detector.
Delayed coincidence with a day-scale window for tagging 232Th series isotopes in KamLAND
Authors: Hachiya Takahiko
Published: May 2021

Decays of 232Th series isotopes such as 212Bi212Po and 208Tl form background events for underground physics experiments. In this study, we performed new delayed coincidence with a day-scale window using data of KamLAND, a 1 kton liquid scintillator detector. We firstly searched for a coincidence of 220Rn–216Po (T1/2 = 0.15 s), prompt coincidence (PC), and then searched for events of 212Bi212Po or 208Tl decays within 2 day from PC. It yields ~80% tagging efficiency with modest, ~10%, deadtime despite the requirement of long time correlation thanks to low accidental coincidence rate of PC. This method will be newly introduced to analyses of solar neutrino measurement at 3 MeV region with KamLAND and neutrinoless double-beta decay search with KamLAND-Zen to reduce the backgrounds.
Optimized Development of Web Front-end Development Technology
Authors: Xiaoshu Wang
Published: May 2021

With the widespread use of the Internet in modern social life, the existing Web technology still has a large room for optimization and development in terms of loading time, response speed, and user Internet experience. Therefore, Internet technicians need to fully understand and master various Web front-end development technologies. Besides, through the technical optimization we can reduce the HTTP errors and requests. Moreover, in order to improve the user’s Internet experience we are supposed to control the file size, reduce the invalid responses and DNS queries reasonably.
Focal Gradient Harmonized Loss Function for Object Detection
Authors: Sun Muye , Huang Hongbo , Hu Zhiying , Ran Qinglin , Liu Yahui
Published: May 2021

Mainstream detectors in the field of object detection usually can be divided into one-stage and two-stage detectors. Compared to the two-stage detectors, one-stage detectors are more efficient and elegant, but are more easily disturbed by imbalanced data during the training. Inspired by the gradient harmonized single-stage detector (GHM detector)[1], we propose a focal gradient harmonizing loss function for classification (FGHM-C). FGHM-C loss function optimizes the method of generating example weights during training, thereby alleviating the impact of long-tailed distribution. Our proposed model achieves 42.0 mAP on COCO test-dev set, which is 0.4 points higher than the original GHM detector.
Research and application of appearance inspection system for spacecraft low frequency electrical connector based on machine vision
Authors: Guo Mingyu , Huang Lei , Yao Lei , Xu Zhen , Fu Guanghui , Feng Tao
Published: May 2021

In order to improve the accuracy and efficiency of the inspection of the appearance quality of the electrical connector in the acceptance process of the low frequency cable, the machine vision recognition technology is studied to realize the appearance quality inspection of the electrical connector on the existing low frequency cable, in order to improve the quality and efficiency of appearance inspection of low-frequency cable connectors, various kinds of defects such as slanting, missing and shrinking wires can be identified automatically.
Research on motor modular drive control technology based on FPGA
Authors: Luo Haifeng , Yuan Jiajin , Weng Shentian , Zhao Jiling , Zhang Tao
Published: May 2021

brushless DC motor is widely used in aviation, aerospace and other fields because of its fast response speed and high operation efficiency. The motor drive module based on FPGA has the advantages of small size and high reliability. In order to carry out the motor modular drive control technology based on FPGA, the electrical drive module and control module are designed, and the correctness of the design is verified by the test, which lays the foundation for the follow-up project implementation.
Analysis of hydrogen isotopes in construction materials by means of electron spectroscopy
Authors: Afanas’ev V P , Bodisko Yu N , Kaplya P S , Lobanova L G , Yu O , Strukov A N
Published: May 2021

The possibility of measuring hydrogen depth profiles by means of electron spectroscopy is demonstrated. In the near-surface layer with a thickness corresponding to the inelastic mean free path (IMFP) the elastic peak electron spectroscopy (EPES) is employed for this purpose. For measuring hydrogen isotope depth profiles deeper in the solid at depths corresponding to the transport mean free path (which is by several orders of magnitude larger than the IMFP) the so-called spectroscopy of reflected electrons (SRE) is used. In this work, the SRE technique is employed for the investigation of a pure beryllium sample and a beryllium sample implanted with deuterium atoms.
Study of the effect of argon pressure on the temperature of a hot target
Authors: Kozin A A , Shapovalov V I , Ahmedov H , Demir A , Korutlu B , Shabalin A E
Published: May 2021

In this work, thermal processes in direct current operating magnetron with hot titanium target are studied in Argon medium. Thermal processes are described by stationary, three-dimensional, heat equation with surface heat source which is the flux of argon ions from the gas discharge. The problem was solved numerically via the Heat Transfer Module in COMSOL Multiphysics Software.
Change in ion sputtering coefficients of targets due to cross-dusting during simultaneous operation of two sputters
Authors: Volpian O D , Kuzmichev A I , Obod Yu A
Published: May 2021

The influence of cross-dusting of silicon and metal targets simultaneously sputtered by argon ions on partial sputtering coefficients of targets materials components is studied to take this effect into account in the technology of gradient optical coating deposition. The effect has been numerically simulated as series of cascades of binary collisions of bombarding ions and recoil atoms with target atoms. Addition of metal atoms (Ti, V, Zr, Hf, Nb and Ta) to the Si target enhances the partial sputtering of Si atoms but addition of Si atoms to the metal targets decreases the partial sputtering of metals atoms. Also the coefficients of reflection (back scattering) of the bombarding argon ions from the targets with different additives have been calculated. It is possible that enhanced sputtering of Si atoms from the coatings with a “heavy” component by reflected neutralized ions would lead to dusting the “heavy” target by silicon.
Research on Detection Technology of Joint Sealing of Large Diameter PVC Water Supply Pipe
Authors: Meng Fanzhao , Yang Ruiqing , Yang Yonghai , Wei Daifeng
Published: May 2021

With the increasing application of PVC water supply pipe in production and life, this paper aims at the problem that there is no single sealing ring connected large diameter PVC pipe interface sealing detection equipment in the construction site of agricultural water supply. According to the sealing test method of negative pressure test, a set of large diameter PVC pipe interface sealing test device is designed, and the corresponding test procedures and standards are put forward. The field sealing test of large diameter PVC pipe interface is carried out, and the portable aviation aluminum box with universal wheel is designed and customized. The device has the advantages of simple structure, easy installation and disassembly, easy carrying, and is suitable for field operation. It provides important equipment support for the better promotion and use of large PVC pipes.
Multi-axis NC machining of integral impeller parts based on NX
Authors: Shan Wenju , Guo Liyu
Published: May 2021

The Integral impeller is widely used in all kinds of turbine machinery and aeroengine. With the improvement of engine performance, the shape of the impeller becomes more and more complex. It has the characteristics of small blade spacing, large distortion and thin blade, etc. The Integral impeller is more difficult to process. This paper analyzes the NC machining technology of the Integral impeller and discusses the parameter setting of the multi-axis NC machining.
Research on the Coordination and Matching of Cylinder Head Gasket Strength and Sealing Performance
Authors: Wang Long , Zuo Zhengxing , Cheng Ying , Zhu Xinran
Published: May 2021

In this paper, the cylinder head gasket of a certain type of diesel engine is taken as the research object. Under the condition of changing the mechanical load parameters, the changing trend of the strength and sealing performance of the cylinder head gasket is analyzed, and then its reliability and durability are evaluated. Through the analysis, we can see that the changing trend of the strength and sealing performance of the cylinder head gasket is the opposite. Therefore, in this paper, the fatigue life and sealing performance of the cylinder head gasket are regarded as factors with equal weight, and the total coordination coefficient is introduced to measure the change of the strength and sealing performance of the cylinder head gasket after changing the explosion pressure and bolt preload, the best loading scheme is selected.
A New Approach for Testing Engagement Characteristics of Clutch
Authors: Zou Xinyu , Wang Yang
Published: May 2021

In this paper, a new method for testing the dynamic engagement characteristics of clutch is proposed. This approach is that the dynamic characteristics of clutch is simulated by finite element method. For the fluid friction characteristics, the average Reynolds equation proposed by Patir and Cheng is improved, and dimensionless parameters are adopted, which is applied to calculate the viscous torque. For the boundary friction characteristics, a surface elastic contact model is established to calculate rough contact torque. For the mixed friction characteristics, total torque consists of viscus torque and rough contact torque. The simulation and bench test are completed to verify the validity of model proposed. The model proposed can be used to guide the design of clutch in early stages of product development.
Construction Technique for TBM to Cross Unfavorable Geological Sections
Authors: Quan Yongwei , Pan Xuyong , Li Xiulin
Published: May 2021

The diversion tunnel of VI Section, XE Project in Xinjiang Autonomous Region was constructed with an open-type tunnel boring machine (TBM). Concerning the unfavorable geological sections encountered during TBM tunneling in the project construction, the author has summarized the engineering countermeasures used to improve the efficiency and construction safety of TBM tunneling.
Research on Subway Construction Monitoring and Warning System Based on Internet of Things Technology
Authors: Zheng Xuezhao , Guo Hang
Published: May 2021

Aiming at the problems that the low specification, underinvestment and the low professional level of risk management existed in the subway construction at present, analyzed the construction demand of monitoring and warning system for subway construction, a king of subway construction monitoring and warning system based on internet of things technology was proposed. Internet of things, wireless communication, cloud computing and other technologies was exploited to comprehensive sense and monitor of the construction site; Researched the personnel positioning system based on Mesh technology to realize wireless self-organizing network of transmit data and improve positioning accuracy and response speed; By combining the video monitoring with wireless sensing technology, real-time monitoring of field operations was realized, ensure the safety of workers’ lives and “zero hidden danger“ in the field working environment; Data push technology was used to achieve mobile video monitoring, stagewise and classified management, improve the flexibility of safety management.
A new rejuvenating technique for cable localized insulation failures of railway locomotives
Authors: Jia JinJun , Zhao YongXiang , Wang JunGou , Liu ZhiWei
Published: May 2021

A new rejuvenating technique, injection plastic technique with standard scales and over coatings, is developed for restoring the localized cable insulation failures of railway locomotives. The materials of cable jacket and insulation layers are pelt with standard scales around the localized fault location. The failed materials are treated visibly to eliminate hidden perils. Matched moulds with over coating spaces are creatively designed and manufactured for rejuvenating cable insulation and jacket layers materials with injection moulding machine. The policies of standard scales and over coatings can well ensure a reliable rejuvenation, good bound seals and well economic benefits.
Concept of biomimetic mechanical foot based on muscle simulation
Authors: Jin Chaoyue , Xiao Jialuan , Cao Chuqi
Published: May 2021

An concept of biomimetic mechanical foot based on muscle simulation is proposed to solve the problems of biped robots, such as unstable motion and inability to start at a high acceleration. Firstly, the human plantar muscles are mechanically simulated according to the force area and various factors, and the plantar mechanical matrix composed of several mechanical units is constructed. The biped robot collects its own motion state data through sensors, and then processes the data through the control system and issues posture instructions to the plantar mechanical matrix. Finally, the mechanical matrix module adjusts the mechanical unit according to the posture instructions, thereby greatly improving the movement of the biped robot’s stability.
Research on temperature error compensation method of vehicle-mounted laser gyro SINS
Authors: Yang Chen , Cai Yuanwen , Xin Chaojun , Shi Meiling
Published: May 2021

In order to solve the problem that the measurement accuracy of vehicle-mounted laser gyro strapdown inertial navigation system (SINS) is affected by the temperature change, a temperature error compensation method which can adapt to the full temperature environment is proposed. Based on the phenomenon that the temperature of the inertial sensor is still rising when the temperature of the temperature control box is kept, a continuous temperature change experiment is designed. Then, Pearson correlation analysis of the output of laser gyro and quartz flexible accelerometer with temperature, temperature rate and temperature gradient has been carried out. Based on that, the temperature error models of gyro and accelerometer are constructed, and the temperature compensation method based on polynomial model is proposed. The results show that this method could compensate the temperature error of the laser gyro and the quartz flexible accelerometer effectively, and the zero-bias stability of them are both improved, especially the zero-bias stability of the accelerometer is improved by at least one order of magnitude, the accuracy of inertial measurement in full temperature environment is improved effectively.
Experimental study on mechanical behavior of welded joints of strain strengthening austenitic stainless steel under 77K
Authors: Si Jun , Ren Facai , Ren Bin
Published: May 2021

With the development of economy and technology, people’s demand for material properties is developing towards the extreme direction of cryogenic temperature and high pressure. The development of materials with better properties has been widely studied. Austenitic stainless steel S30408 is a typical transformation induced plastic steel, that is, the martensite produced after strain affects the mechanical properties of the material, which will improve the yield strength of the material, effectively reduce the wall thickness. Compared with base metal, welded joint is the weakest link in pressure vessel. Therefore, the research on the mechanical properties of the welded joint of strain strengthening austenitic stainless steel can effectively ensure the safety and reliability of the strain strengthening pressure vessel. In this paper, experimental study on mechanical properties of S30408 welded joints with strain-strengthening were carried out.
Residual Stress Recognition Method for Welded Structures based on An Improved Multiple Differential Empirical Mode Decomposition
Authors: Liu Xiaohan , Shi Guangfeng , Liu Weina
Published: May 2021

To overcome the difficulty in accurately identifying the residual stress of complex large welded parts, a multiple differential empirical mode decomposition (MDEMD) method based on grey mean GM(1,1) prediction and mirror symmetry (MS) extension combined with energy entropy is proposed to identify the residual stress state of components. Firstly, the vibration signal of the welded steel plate is collected by the hammering method and preprocessed by MD algorithm. Secondly, GM(1,1) is used to predict the extreme points at the endpoints and mirror symmetry continuation is used to obtain the intrinsic mode function (IMF). Then, the energy value of IMF component is calculated and normalized by energy entropy, and the characteristic parameters are extracted to realize the identification of the residual stress state. The experimental results show that this method can effectively identify the residual stress state of welded components, and the recognition rate reaches 98.7%.
Intelligent Laser Leveling Control System for Cement Concrete Based on MCU Control
Authors: Wei Xinhua , Huang Shuangcheng
Published: May 2021

With the development of urbanization, cement concrete roads are laying more and more, and the requirements are getting higher and higher. The traditional leveling operation has the disadvantages of high labor cost, long time and poor precision. Based on this, a control system of cement concrete leveling based on laser sweeping technology is designed, and the cement concrete leveling control system based on the laser scanning level is designed. The embedded controller STM32 is used as the control core of the system, the laser horizontal plane scanned by the laser swinger is regarded as the horizontal standard of the leveling system. Two rows of laser receiving sensor arrays mounted on the scraping shovel were used to detect the vertical relative position and tilt of the scraping shovel. The stepping motor driving chip TB67S109AFTG was used to drive two stepping motors to realize the automatic adjustment of the vertical position and inclination of the scraping shovel, and realize the automatic leveling function of the laser leveling machine. Finally, the precision reached 4mm.
Study on opening pressure of hydrocephalus shunt under siphon
Authors: Ji Ping , Dong Quancheng , Wan Min , Yao Xiujun , Shi Kai , Sun Xuan
Published: May 2021

The opening pressure of the hydrocephalus shunt with the siphon device was studied and analyzed in this paper. The influence of fluid velocity and siphon height on the opening pressure of hydrocephalus shunt is analyzed. According to the national medical industry standards, the hydrocephalus shunt must be opened by the liquid column detection method. In this paper, computational fluid dynamics was used to simulate the liquid column pressure, and the interaction analysis of the two factors of flow rate and siphon height was carried out. Finally, the influence of flow velocity and siphon height on the opening pressure of hydrocephalus shunt was obtained in this paper, and the relevant formula of the influence of these two factors on the opening pressure was obtained.
Calculation method of steady-state fault current for offshore wind farm
Authors: Miao Weiying , Gao Houlei , Xu Bin
Published: May 2021

In order to improve the efficiency of solving the steady-state fault current of the offshore wind farm current collection system, In this method, the equivalent model of the PMSG and the VF control converter is established by taking into account the low-voltage ride-through in the case of failure. The Newton-Raphson method is used to iteratively calculate the fault equivalent network. By establishing a simulation model under PSCAD, the symmetric and asymmetrical faults in the collector system of a grid-connected permanent magnet wind turbine connected to the VSC-HVDC are simulated. Simulation results verify the effectiveness and accuracy of the calculation method.
Study on dynamic characteristic optimization of virtual inertia control for the grid-connected converters in DC micro grid
Authors: Wang Xue , Yang Tingyu
Published: May 2021

In order to reduce the transient time and voltage deviation due to voltage variation while increasing the system inertia of the DC microgrid, a new adaptive control method for the parameters of the grid-connected end is proposed. Firstly, a grid-connected converter control strategy mathematical model is established. Secondly, the influences of different control parameters on the dynamic characteristics of the system are studied. An adaptive equation based on the parameters of voltage deviation and voltage change rate of DC bus is proposed. Finally, through MATLAB/Simulink simulation, the simulation results of the traditional drooping control, the virtual inertial control with fixed parameters and the control strategy proposed in this paper are compared and analyzed. The result shows that the proposed control method has better dynamic characteristics.
Quadric Lyapunov Algorithm for Stochastic Networks Optimization with Q-learning Perspective
Authors: Li Hu , Zhang Xinguang , Bai Jinliang , Sun Heng
Published: May 2021

In this article, we investigate stochastic networks optimization using Quadric Lyapunov Algorithm (QLA) with Q-learning perspective. We proposed firstly a model of stochastic queueing networks with power constraints. QLA is then proposed aiming at minimizing an expression containing Lyapunov drift. Based on the analysed similarity between QLA and Q-learning, we show the possibility and feasibility of Q-learning. Simulation of a simple queue network model is carried out, and results using both QLA and Q-learning are compared.
The Influence of Different Constitutive Model Relations on Mechanical Behavior of Crack Tip Plastic Zone
Authors: Shao Xiaolin , Wang Jing , Zhang Yan , Huang Huiru
Published: May 2021

For ductile materials with cracks, when the stress at crack tip exceeds the yield strength, a plastic zone will be formed around crack tip. In this paper, the extended finite element method(XFEM) in ABAQUS was used to simulate the crack, and the mechanical behaviors of crack tip plastic zone under different constitutive models were studied by taking the three-point bending specimen as the research object. The COD experiment and theoretical verification of three-point bending demonstrate the effectiveness of this method. The effect of the plastic modulus on size of crack tip plastic zone under the double broken line constitutive model is analyzed, and the effects of the load on plastic zone size and stress distribution near crack tip under the true stress-strain constitutive model is discussed. Finally, the difference of stress distributions around crack tip obtained from two constitutive models is compared.
Design of functional electrical stimulator for foot drop rehabilitation
Authors: Wang Jinxiang , Zhang Yulin
Published: May 2021

This paper designed a functional electrical stimulator controlled by STM32F103 microprocessor for the rehabilitation of foot drop patients. The frequency, pulse width, period and other parameters of the electrical stimulator are set by the upper computer and transmitted to the remote controller. The remote controller then controls the lower computer to adjust the stimulus intensity through Bluetooth for electrical stimulation treatment. The electric stimulator outputs the stimulus current through the boost control circuit and the constant current output circuit. The results show that the functional electrical stimulator can adjust the therapeutic pulse in the range of 0-100mA current intensity, 17-40Hz frequency and 100-300μs pulse width. The design is easy to use, high degree of automation, easy to use in the home and hospital.
Design and experiments of a bio-inspired tensegrity spine robot for active space debris capturing
Authors: Feng Xiaogang , Wu Zhigang , Wang Zijie , Luo Jiahui , Xu Xiaoming , Qiu Zhoujingzi
Published: May 2021

Aiming at active space debris capturing, this paper proposes a novel tensegrity spine robot, inspired by the structure and mechanism of vertebrates’ spine. It consists of a series of conical rigid elements, which are linked with springs and stabilized in a tension network. The continuous bending of the robot is achieved by the actuation of three sets of cables. A prototype is built and a closed-loop control method is proposed for proof-of-concept experiments, including bending motion control, capturing a non-cooperative target, and tests of load performance. The experimental results show that the proposed tensegrity spine robot has potential application prospects in space debris capturing.
Design of the blow-drying device for gearbox housing based on stm32 microcomputer
Authors: Yang Xiaoyan , Hou Xujie , Wang Yanyan , Zhang Qiang
Published: May 2021

Based on STM32 microcontroller, the design scheme of the gear box shell drying device is proposed, and the design framework and software design flow of the device are given. On the basis of high-performance MCU, the device can automatically complete the intelligent drying of the gearbox shell, and can carry out the secondary recovery of cutting fluid. At the same time, the device is equipped with a monitoring system, which can monitor the internal influencing factors according to the specified requirements, so as to achieve the goal of safety and efficiency.
On-line detection device for high temperature forgings based on laser triangulation
Authors: Bian Shaoshun , Zhou PengZhong , Xu Jiawei , Zhang Jin , Shan Debin
Published: May 2021

This paper takes the online detection equipment of high temperature forgings in the forging environment as the research goal, and uses laser triangulation to perform 3D point cloud imaging of high temperature forgings, and then conducts online detection of the defects, temperature, position, size and other parameters of the forgings. Real-time information feedback of measurement results, and timely adjustment of forging equipment and improvement of production process routes based on the feedback results, thereby effectively improving forging accuracy and forging efficiency, and reducing the work intensity of workers.
Optimal Design of Flexspline in New Modular Robotic Joints Considering Position Keeping Conditions
Authors: Luo Yuyang , Li Zhaoyang , Wu Hongyu
Published: May 2021

In order to improve the service life of modular joints and meet the requirements of compact structure, considering the position keeping conditions of modular joints, a multi-objective optimization design method for the maximum stress and tube length of the new modular joint flexspline was proposed. This method established a finite element analysis model based on a new modular joint structure, conducted a thermo-mechanical coupling analysis on the joint under the holding state, and obtained the stress distribution of the flexible wheel. Plackett-Burman factorial design was used to screen the significant factors that affect the maximum stress. Based on the Box-Behnken test method and the least square method, the second-order response surface approximate model of the maximum stress of the flexspline was established. Taking the geometric structure parameters of the harmonic drive components as the design variables, and the maximum stress and tube length of the flexspline as the design goals, the response surface approximate model is optimized through the multi-objective genetic algorithm. The optimization calculation example of the new modular joint shows that the method can reduce the maximum stress of the flexspline while reducing the tube length, achieving the purpose of reducing the joint volume and increasing the service life.
Design of Geopolymer for Removal of Nitrogen in Industrial Wastewater based on Artificial Intelligence Technology
Authors: Yu Yangmei
Published: May 2021

In the era of big data, as an essential direction of international development in the next few decades, artificial intelligence has an extensive application suitable for all fields of life. Nowadays, artificial intelligence technology is also integrated into production and life. As a new unique material, geopolymer has been widely used thanks to its properties. Due to their special network structure, geopolymer materials have a higher temperature and mechanical properties than other materials, such as cement, ceramics, and metals. The experiment results show that the artificial intelligence technology is very suitable for the geopolymer design for nitrogen removal from industrial wastewater, and the satisfaction is as high as 72.3%. In this paper, industrial wastewater is used as raw material for nitrogen removal, and the future development direction of geopolymer research is analyzed. We hope to provide a novel way for the utilization of industrial wastewater.
Sand Bar Evolution Process Numerical Simulation Analyze Based on two Dimensional Numerical Model
Authors: Jiang Caodong , Ma Liangchao , Li Dongfeng , Zhang Hongwu , Li Zihao
Published: May 2021

The sand bar lies near the entrance to the sea, which is not only detrimental to the flood discharge and sediment discharge of the river, but also an important factor causing the swing the flow path to the sea. With the formation and development of the sand bar, the form of the sand bar is constantly changing, the river is expected to extend continuously, and the water level and velocity of the estuary river change within a certain range, thus affecting the estuary flood control and river management measures. It is of great significance to study the development process of sand bar and its form for flood control of estuarine rivers and to put forward reasonable control measures of the sand bar. The sediment inflow into the sea is calculated by using the validated two - dimensional numerical model of estuarine and rivers. In this paper, the variation and development process of the sediment form with time and space are analyzed from the following aspects: the process of sediment deposition thickness into the sea, the distribution chart of sediment deposition thickness along the direction of water flow into the sea, the process chart of seabed deposition height, the variation of intraday flow velocity along the sea and the analysis of the temporal and spatial variation of sediment concentration, etc. The calculated and analyzed results are consistent with the measured data.
Research on Intelligent Campus System Design Based on BIM & VR/AR Technology
Authors: Wu Bei , Hao Ruoyan , Li Huanyu , Chai Qian , Wang Yaning
Published: May 2021

With the new form of social development dominated by Internet technology innovation, more and more domestic colleges and universities are applying virtual reality technology to the construction of smart campuses. This method of combining virtual reality and augmented reality (VR & AR) technology with smart campuses has realized campus The goal of informatization, intelligence and visualization.
Parameter identification of general damping model based on structural dynamic response
Authors: Sun Qian , Zhang Kun , Ju Jianmin
Published: May 2021

A general damping model suitable for linear systems is proposed, which is not limited by the traditional damping model, and the parameters of the damping model are identified by using the inversion algorithm based on the sensitivity of the structure dynamic response. Firstly, the expression of the general damping model is constructed, and the sensitivity formula of the dynamic response of the structure to the parameters of the damping model is deduced. Then, the identification equation of structural damping parameter inversion is constructed, and the regularization method is used to solve the equation in an iterative way. Finally, the applicability and identifiability of the general damping mathematical model are verified by taking a 12-story shearing frame as an example. The numerical simulation results show that the general damping mathematical model has higher accuracy than the classical damping model in damping parameter identification and dynamic calculation.
Research on calculation model of Tower Impulse resistancebased on EMTP
Authors: Hongtao Ren , Yi Li Chen
Published: May 2021

Accurate determination of impulse grounding resistance of tower grounding body is the premise to improve the lightning withstand level of transmission line. The current research mostly ignores the nonlinear effect of soil spark discharge. Based on the analysis of the idea and conception of the equivalent model of grounding body considering spark discharge effect, two simulation models based on EMTP are proposed. The two simulation models can well simulate the inductance effect and spark discharge effect when lightning current flows through grounding body, and improve the grounding body model under impulse condition. The comparison results show that the simulation results are in good agreement with the field measurement results.
Design and Simulation of Sandwich Structure of Exoskeleton Backplate Based on Biological Inspiration
Authors: Peng Xuefeng , Dai Zongmiao , Liu Jiasheng , Wang Yongyuan
Published: May 2021

The backplate is the main skeleton of the exoskeleton robot, and its structural strength and lightweight design are very important to the body structure of exoskeleton. In this paper, a design scheme of grille reinforced foam sandwich structure based on biological inspiration is presented. By analyzing the influence of core thickness on the mechanical properties of the sandwich structure, a new sandwich structure of exoskeleton backplate with a surface thickness of 2mm and a core thickness of 15mm was designed. Based on finite element software ABAQUS, the simulation calculation was carried out. The results show that the maximum stress of the sandwich structure is 298.5Mpa and the maximum strain value is 2730με, which is less than the allowable value. This meets the structural strength design and lightweight design requirements.
Distributed VOCs Gas Monitoring System in Large and Medium Cities
Authors: Wei Xinwei , Wang Yanyang , Xia Dingyuan
Published: May 2021

VOCs are the most important task of urban air pollution control at present, and its wide variety and emission range are important factors to produce haze. In this paper, a ladder distributed node network detection platform based on high performance electrochemical nanoarray gas detection chip and NB-IoT low power consumption is proposed. It is beneficial for environmental protection department to supervise VOCs, and reduce energy consumption while ensuring accuracy.
Research on Electromagnetic Wave Propagation and Optical Characteristics Based on Optical Transfer Matrix Method
Authors: Yan Zhang
Published: May 2021

The processing of electromagnetic waves by means of optical transmission matrix can be applied through multi-layer homogenization media, and finally real-time transmission can be realized. After that, it can derive the transmission matrix based on the interface and propagation matrix construction, and finally obtain the reflection and permeability coefficients. This article summarizes the content of the transmission matrix method based on previous work experience. The author discusses the propagation and optical characteristics of physical electromagnetic waves based on the optical transmission matrix method from four aspects: reflection-increasing film analysis, DBR design, reflectance calculation of fiber multi-directional laminates, plane wave propagation and reflection in the medium.
Welding procedure qualification of Q345 grade fire-resistant steel based on Jmat-pro calculation
Authors: Rongchun Wan , Yimeng Fang , Baoshan Cao , Qingyan Ma , Xun Gong
Published: May 2021

The welding process of two Q345 grade low Mo (about 0.25 wt.%) fire-resistant steels will be calculated and evaluated in this paper. The continuous cooling transformation (CCT) curve and isothermal transformation (TTT) curve of test steel were calculated by Jmat-pro software. The welding processes of steels were evaluated by measuring the continuous cooling transition (SH-CCT) curves of welding heat affected zone. The test results show that when the actual cooling time of Q1 steel is t 8/5>43s, cracking does not occur in the HAZ of welding and near the fusion zone, while when t 8/5<43s, cracking may occur in the HAZ or fusion zone; When the actual cooling time of Q2 steel is t 8/5>44s, cracking does not occur in the welding heat affected zone and the vicinity of the fusion zone, while when t 8/5<44s, cracking may occur in the heat affected zone or the fusion zone. In addition, Jmat-pro software has a certain accuracy for the calculation of Ac 3, but has a large error for the continuous cooling transformation (CCT) curve, especially the difference between the calculated value and the measured value of Q2 steel is larger, which only has reference value.
Design and implementation of spatial analysis module for forestry ecological engineering monitoring system
Authors: Yang Yuan
Published: May 2021

Spacial Analyst(SA)is the core technology of GIS and it’s also the technology which is different from other information systems. In this paper, the design of spatial analysis module is a sub-module of forestry ecological engineering monitoring system. in view of the forest is dispersed, vast and dynamic, the long-term characteristic, this paper designs its functions include digital terrain analysis, spatial characteristics of geometric analysis, statistical analysis, etc., and it briefly introduces the method and technical requirements of realization of each function module, the result is suitable for resourceful forestry workers are applied in the spatial data processing and analysis.