bluuebunny/crossref_metadata_2025 huggingface dataset:
Remote sensing and electromagnetic wave behaviour to measure vegetation phenology with physics
Authors: Woźniak Edyta , Gabryszewski Ryszard , Dziob Daniel
Published: May 2020

Interdisciplinary models of teaching have been present in education systems for at least 30 years. The idea of the interdisciplinarity is to show students the contextualisation of subject knowledge, its relation to real-life problems and to build skills across traditional disciplinary boundaries. This is essential to future competitiveness since innovations frequently occur at the interface of disciplines when people are able to collaborate. Schools try to respond to the need to prepare students for an interdisciplinary and collaborative job market by modifying the curricula and training teachers. But one of the most primary and difficult problems is preparing a truly interdisciplinary lesson or a project. It seems that all complex issues could be good examples for this purpose. One of these complex issues is the study of climate change, which requires the collaboration of different specialists and a comprehensive understanding of the problem in different scientific fields: physical, geographical, biological, social, engineering, etc. The paper presents an interdisciplinary project which links knowledge within a few different science areas around the real-life problem important for students. The work shows the developed and tested interdisciplinary educational project ‘Panta Rhei’ which integrates physics and other STEM subjects to present the biological and social consequences of changes in vegetation periods for different climate zones. It shows how Earth observation research can be utilised in schools for teaching physics and other science subjects. The project was validated on a group of Polish teachers. In the paper we present the whole project together with teachers' opinions.
A teaching module for blackbody radiation using the continuous
spectra of stars
Authors: Kardaras Ioannis , Kallery Maria
Published: May 2020

Teaching blackbody radiation within the framework of astrophysics can motivate
students to learn and obtain a more profound and qualitative understanding of
the subject. In this paper we present a teaching module that intertwines
teaching blackbody radiation via the continuous spectrum of hot objects,
especially the stars. The module’s approach was that of guided inquiry.
Students of upper secondary education carried out experimental activities that
included a combination of hands-on activities and computer processing. They
actively and creatively engaged in the activities which helped them develop a
more complex and structured knowledge of the subject. A ten-multiple choice
questionnaire was administered before and after the implementation and the data
were qualitatively and quantitatively analyzed. The results showed that the
intervention had a significant impact on students’ learning outcomes.
Our twinkling sun
Authors: Haigh David , Hikmet Hussein Ahmed , Moore Andrew , Hughes Jennifer
Published: May 2020

It is well known that the twinkling of stars in the night sky is due to
turbulence within the earth’s atmosphere causing localised fluctuations in
refractive index. The paper describes a method for demonstrating the effect to
learners during the daytime. This is accomplished by detecting audio frequency
fluctuations in the level of direct sunlight and then presenting the result via
headphones or a loudspeaker. The paper makes several suggestions for further
work and potential applications of the technique in different fields of study
are discussed.
Recent progress in graphene terahertz modulators*
Authors: Chen Xieyu , Tian Zhen , Li Quan , Li Shaoxian , Zhang Xueqian , Ouyang Chunmei , Gu Jianqiang , Han Jiaguang , Zhang Weili
Published: May 2020

Graphene has been recognized as a promising candidate in developing tunable terahertz (THz) functional devices due to its excellent optical and electronic properties, such as high carrier mobility and tunable conductivity. Here, we review graphene-based THz modulators we have recently developed. First, the optical properties of graphene are discussed. Then, graphene THz modulators realized by different methods, such as gate voltage, optical pump, and nonlinear response of graphene are presented. Finally, challenges and prospective of graphene THz modulators are also discussed.
Measurement and verification of concentration-dependent diffusion coefficient: Ray tracing imagery of diffusion process*
Authors: Wei Li , Meng Wei-Dong , Sun Li-Cun , Cao Xin-Fei , Pu Xiao-Yun
Published: May 2020

Ray tracing method is used to study the propagation of collimated beams in a liquid–core cylindrical lens (LCL), which has dual functions of diffusion cell and image formation. The diffusion images on the focal plane of the used LCL are simulated by establishing and solving both linear and nonlinear ray equations, the calculated results indicate that the complex imaging results of LCL in inhomogeneous media can be treated by the law of ray propagation in homogeneous media under the condition of small refractive index gradient of diffusion solution. Guided by the calculation conditions, the diffusion process of triethylene glycol aqueous solution is experimentally studied at room temperature by using the LCL in this paper. The spatial and temporal concentration profile C
e(z, t) of diffusion solution is obtained by analyzing diffusion image appearing on the focal plane of the LCL; Then, the concentration-dependent diffusion coefficient is assumed to be a polynomial D(C) = D
0 × (1 + α
1
C + α
2
C
2 + α
3
C
3 + ⋅). The finite difference method is used to solve the Fick diffusion equation for calculating numerically the concentration profiles Cn
(z, t). The D(C)of triethylene glycol aqueous solution is obtained by comparing the Cn
(z, t) with C
e(z,t). Finally, the obtained polynomial D(C) is used to calculate the refractive index profiles nn
(z,t)s of diffusion solution in the used LCL. Based on the ray propagation law in inhomogeneous media and the calculated n(z,t), the ray tracing method is used again to simulate the dynamic images of the whole experimental diffusion process to varify the correctness of the calculated D(C). The method presented in this work opens up a new way for both measuring and verifying the concentration-dependent liquid diffusion coefficients.
Effect of radio frequency bias on plasma characteristics of inductively coupled argon discharge based on fluid simulations*
Authors: Sun Xiao-Yan , Zhang Yu-Ru , Chai Sen , Wang You-Nian , Chu Yan-Yan , He Jian-Xin
Published: May 2020

A fluid model is employed to investigate the effect of radio frequency bias on the behavior of an argon inductively coupled plasma (ICP). In particular, the effects of ICP source power, single-frequency bias power, and dual-frequency bias power on the characteristics of ICP are simulated at a fixed pressure of 30 mTorr (1 Torr = 1.33322 × 102 Pa). When the bias frequency is fixed at 27.12 MHz, the two-dimensional (2D) plasma density profile is significantly affected by the bias power at low ICP source power (e.g., 50 W), whereas it is weakly affected by the bias power at higher ICP source power (e.g., 100 W). When dual-frequency (27.12 MHz/2.26 MHz) bias is applied and the sum of bias powers is fixed at 500 W, a pronounced increase in the maximum argon ion density is observed with the increase of the bias power ratio in the absence of ICP source power. As the ratio of 27.12-MHz/2.26-MHz bias power decreases from 500 W/0 W to 0 W/500 W with the ICP source power fixed at 50 W, the plasma density profiles smoothly shifts from edge-high to center-high, and the effect of bias power on the plasma distribution becomes weaker with the bias power ratio decreasing. Besides, the axial ion flux at the substrate surface is characterized by a maximum at the edge of the substrate. When the ICP source power is higher, the 2D plasma density profiles, as well as the spatiotemporal and radial distributions of ion flux at the substrate surface are characterized by a peak in the reactor center, and the distributions of plasma parameters are negligibly affected by the dual-frequency bias power ratio.
Selective linear etching of monolayer black phosphorus using electron beams*
Authors: Pan Yuhao , Lei Bao , Qiao Jingsi , Hu Zhixin , Zhou Wu , Ji Wei
Published: May 2020

Point and line defects are of vital importance to the physical and chemical properties of certain two-dimensional (2D) materials. Although electron beams have been demonstrated to be capable of creating single- and multi-atom defects in 2D materials, the products are often random and difficult to predict without theoretical inputs. In this study, the thermal motion of atoms and electron incident angle were additionally considered to study the vacancy evolution in a black phosphorus (BP) monolayer by using an improved first-principles molecular dynamics method. The P atoms in monolayer BP tend to be struck away one by one under an electron beam within the displacement threshold energy range of 8.55–8.79 eV, which ultimately induces the formation of a zigzag-like chain vacancy. The chain vacancy is a thermodynamically metastable state and is difficult to obtain by conventional synthesis methods because the vacancy formation energy of 0.79 eV/edge atom is higher than the typical energy in monolayer BP. Covalent-like quasi-bonds and a charge density wave are formed along the chain vacancy, exhibiting rich electronic properties. This work proposes a theoretical protocol for simulating a complete elastic collision process of electron beams with 2D layers and will facilitate the establishment of detailed theoretical guidelines for experiments on 2D material etching using focused high-energy electron beams.
Low-power electro–optic phase modulator based on multilayer cgraphene/silicon nitride waveguide*
Authors: Ji Lanting , Chen Wei , Gao Yang , Xu Yan , Wu Chi , Wang Xibin , Yi Yunji , Li Baohua , Sun Xiaoqiang , Zhang Daming
Published: May 2020

Electro–optic modulator is a key component for on-chip optical signal processing. An electro–optic phase modulator based on multilayer graphene embedded in silicon nitride waveguide is demonstrated to fulfill low-power operation. Finite element method is adopted to investigate the interaction enhancement between the graphene flake and the optical mode. The impact of multilayer graphene on the performance of phase modulator is studied comprehensively. Simulation results show that the modulation efficiency improves with the increment of graphene layer number, as well as the modulation length. The 3-dB bandwidth of around 48 GHz is independent of graphene layer number and length. Compared to modulator with two- or four-layer graphene, the six-layer graphene/silicon nitride waveguide modulator can realize π phase shift at a low-power consumption of 14 fJ/bit when the modulation length is 240 μm.
Understanding the Li diffusion mechanism and positive effect of current collector volume expansion in anode free batteries*
Authors: Zhuang Yan , Zou Zheyi , Lu Bo , Li Yajie , Wang Da , Avdeev Maxim , Shi Siqi
Published: May 2020

In anode free batteries (AFBs), the current collector acts as anode simultaneously and has large volume expansion which is generally considered as a negative effect decreasing the structural stability of a battery. Moreover, despite many studies on the fast lithium diffusion in the current collector materials of AFB such as copper and aluminum, the involved Li diffusion mechanism in these materials remains poorly understood. Through first-principles calculation and stress-assisted diffusion equations, here we study the Li diffusion mechanism in several current collectors and related alloys and clarify the effect of volume expansion on Li diffusion respectively. It is suggested that due to the lower Li migration barriers in aluminum and tin, they should be more suitable to be used as AFB anodes, compared to copper, silver, and lead. The Li diffusion facilitation in copper with a certain number of vacancies is proposed to explain why the use of copper with a thickness ⩽ 100 nm as the protective coating on the anode improves the lifetime of the batteries. We show that the volume expansion has a positive effect on Li diffusion via mechanical–electrochemical coupling. Namely, the volume expansion caused by Li diffusion will further induce stress which in turn affects the diffusion. These findings not only provide in-depth insight into the operating principle of AFBs, but also open a new route toward design of improved anode through utilizing the positive effect of mechanical–electrochemical coupling.
Thickness-dependent structural stability and transition in molybdenum disulfide under hydrostatic pressure*
Authors: Dong Jiansheng , Ouyang Gang
Published: May 2020

Understanding the physical mechanism of structural stability and transition in various polytypes of layered transition metal dichalcogenides under the external stimulus is of crucial importance for their new applications. Here, we investigate the thickness-dependent structural properties of MoS2 under the condition of hydrostatic pressure in terms of bond relaxation and thermodynamics considerations. For both types of MoS2 structures, we find that the transition and metallization are significantly modulated by hydrostatic pressure and the number of layers. We establish a pressure-size phase diagram to address the transition mechanism. Our study not only provides insights into the thickness-dependent structural properties of MoS2, but also shows a theoretical guidance for the design and fabrication of MoS2-based devices.
A 3-kHz Er:YAG single-frequency laser with a ‘triple-reflection’ configuration on a piezoelectric actuator*
Authors: Huang Shuai , Wang Qing , Zhang Meng , Chen Chaoyong , Wang Kaixin , Gao Mingwei , Gao Chunqing
Published: May 2020

A novel Er:YAG laser system operating at 1645 nm with high pulse-repetition-frequency (PRF) of kHz level is demonstrated. A ring cavity with double gain medium end-pumped by two fiber lasers is utilized to obtain high pulse energy. A novel ‘triple-reflection’ configuration on a piezoelectric actuator (PZT) is adopted to achieve high-repetition-rate at 3-kHz operation with the ramp-fire locking method. Single frequency pulses with maximum average power of 18.3 W at 3 kHz are obtained, and the pulse duration time is 318 ns. The full line width at half maximum (FWHM) of the pulses measured by the heterodyne technique is 1.71 MHz at 3 kHz. To the best of our knowledge, this is the highest PRF single-frequency laser pulses achieved based Er:YAG gain medium.
An open-loop control algorithm of the active reflector system of FAST
Authors: Li Hui , Jiang Peng
Published: May 2020

An open-loop control algorithm is put forward for continuous paraboloid deformation of the active reflector system of the Five-hundred-meter Aperture Spherical radio Telescope (FAST). The method is based on a calibration database and interpolation in 2D spatial domain and temperature domain, respectively. It is completely independent of real-time measurement of cable nodes so that it has advantage of working all-weather and no additional electro-magnetic interference (EMI). Furthermore, its control accuracy can be effectively improved via reasonable layout of the calibrated paraboloids and increasing calibration accuracy. Meanwhile deformation safety is considered via calibration as well. Finally its control accuracy is also confirmed via site measurements of paraboloid deformations.
FAST VLBI: current status and future plans
Authors: Chen Ru-Rong , Zhang Hai-Yan , Jin Cheng-Jin , Gao Zhi-Shen , Zhu Yan , Zhu Kai , Jiang Peng , Yue You-Ling , Lu Ji-Guang , Zhang Bo , Jiang Wu , Zhu Ren-Jie , Guo Shao-Guang , Xia Bo , Zhao Rong-Bing , Collaboration FAST
Published: May 2020

The Five-hundred-meter Aperture Spherical radio Telescope (FAST) is the largest single-dish radio telescope in the world, and is now being commissioned after the first light in September 2016. Very long baseline interferometry (VLBI) is among the key science topics according to the original design. The FAST VLBI system has been established, and the first VLBI fringe has been successfully obtained. FAST will significantly improve the sensitivity of the existing VLBI networks in the future, and some science projects in need of high sensitivity will benefit from its participation.
HI hydrolysis-derived intermediate as booster for CsPbI3 perovskite: from crystal structure, film fabrication to device performance
Authors: Li Zhizai , Jin Zhiwen
Published: May 2020

Nowadays, inorganic CsPbI3 perovskite solar cells (PSCs) have become one of the most attractive research hotspots in photovoltaic field for its superior chemical stability and excellent photo-electronic properties. Since the first independent report in 2015, the power conversion efficiency (PCE) of CsPbI3 based PSCs has sharply increased from 3.9% to 19.03%. Importantly, during the developing process of CsPbI3 PSCs, HI hydrolysis-derived intermediate plays an important role: from stabilizing the crystal structure, optimizing the fabricated film to boosting the device performance. In this review, the different crystal and electronic structures of CsPbI3 are introduced. We then trace the history and disputes of HI hydrolysis-derived intermediate to make this review more logical. Meanwhile, we highlight the functions of HI hydrolysis-derived intermediate, and systematically summarize the advanced works on CsPbI3 PSCs. Finally, the bottlenecks and prospects are revealed to further increase the CsPbI3 PSCs performance.
The strategies for preparing blue perovskite light-emitting diodes
Authors: Lu Jianxun , Wei Zhanhua
Published: May 2020

Metal halide perovskites have attracted tremendous interest due to their excellent optical and electrical properties, and they find many promising applications in the optoelectronic fields of solar cells, light-emitting diodes, and photodetectors. Thanks to the contributions of international researchers, significant progress has been made for perovskite light-emitting diodes (Pero-LEDs). The external quantum efficiencies (EQEs) of Pero-LEDs with emission of green, red, and near-infrared have all exceeded 20%. However, the blue Pero-LEDs still lag due to the poor film quality and deficient device structure. Herein, we summarize the strategies for preparing blue-emitting perovskites and categorize them into two: compositional engineering and size controlling of the emitting units. The advantages and disadvantages of both strategies are discussed, and a perspective of preparing high-performance blue-emitting perovskite is proposed. The challenges and future directions of blue Pero-LEDs fabrication are also discussed.
Mo5+ doping induced interface polarization for improving performance of planar perovskite solar cells
Authors: Jiang Yurong , Yang Yue , Liu Yiting , Yan Shan , Feng Yanxing , Xia Congxin
Published: May 2020

In this paper, we investigate how interface-induced polarization affects the photovoltaic performance of hybrid perovskite solar cell (PSC) devices. The polarization of the hole transport layer (HTL) is regulated through incorporating metallic-like MoO
x
into PEDOT:PSS. The common MoO3 doped into PEDOT:PSS is used as a reference, and the device that used PEDOT:PSS-MoO
x
as the HTL shows an enhanced J
sc and FF compared to the reference device. The open-circuit photovoltage decay and impedance spectroscopy measurements indicate that trap-assisted recombination is effectively suppressed at the interface between the hybrid perovskite and the PEDOT:PSS-MoO
x
HTL, while severe trap assisted recombination takes place at the perovskite/PEDOT:PSS and perovskite/PEDOT:PSS-MoO3 interface. We attribute these experimental findings to the fact that the incorporation of metallic-like Mo5+ into PEDOT:PSS enhances the conductivity of HTL and the interface polarization between PEDTOT:PSS layer and perovskite, which helps to induce an interface polarization electric field to facilitate separation of charges and screen the recombination between the traps and free charges.
The analysis of air-cooled heat exchanger for Reactor Cavity Cooling System (RCCS) on Experimental Power Reactor (RDE) design
Authors: Susmikanti Mike , Yunus Muhammad , Tjahjono Hendro , Kusumastuti Rahayu , Sulistyo Jos Budi
Published: May 2020

The National Nuclear Energy Agency (BATAN) is designing the Experimental Power Reactor (RDE). The Reactor Cavity Cooling System (RCCS) is a new basic design in the nuclear power plant. It will be incorporated into High-Temperature Reactors (HTR), which is one proposed generation of IV reactors. While HTR has been designed and operated, the RCCS design is unique to the recent generation of gas-cooled reactors as a passive decay heat removal system. However, many aspects of the new air- or water-cooled design still need to be investigated on RCCS. The temperature, mass flow, configuration of the riser, and number of the risers on the water-cooled heat exchanger system which is used is a necessary test. The RCCS designs have not been studied for the RDE design. The heat-transfer and fluid-flow on the RCCS facility have not been investigated for the air-cooled cavity cooling system. The aim of this study is to examine the condition of the air-cooled heat exchanger of RCCS for RDE 10 MWth design. The pressure, temperature, and velocity with certain diameters of cooling pipes are computed with FLUENT 6.3 computational fluid dynamics (CFD) software package under a mass flow rate variation. The pressure, the flow velocity and delta temperature outlet were examined on the RCCS process. The air-cooled heat exchanger in RDE basic design was found to attain safe operation.
Studied of Tritium Breeding Ratio on HCLL (Helium Cooled Lithium-Lead) Fusion Blanket by Using MCNP Program
Authors: Rosidah M Indah , Suud Zaki , Yazid Ilham Putra
Published: May 2020

The fusion reactor using a tritium-deuterium reaction is going to be a prolific source of 14.1 MeV (80% of fusion energy) neutrons, which will release from the plasma. This reactor features a major radius of 8.1 m and a minor radius of 2.5 m. Thus, one part of the fusion reactor, which is a basic design is Blanket Module (BM). One of the two European blanket concepts is Helium Cooled Lithium Lead (HCLL). HCLL blanket uses Pb-Li as a neutron multiplier, Li as a breeder, and He as a cooler is in high pressure (8 MPa). The study goal is to investigate the feasibility of blanket reactors, such as neutron analysis, shield efficiency, and tritium breeding capabilities. This calculation was simulated to achieve TBR value more than one, which will assure tritium self-sufficiency in steady-state operations. The MCNP program with Monte Carlo is a tool for calculating this. The neutron flux produced by this simulation shows that the reactor does no leak. And the production of tritium from breeding blanket will be optimal when the utilizing of breeding materials is Pb-Li.
Neutronic Analysis of Lead208-Bismuth Eutectic-Cooled Modified CANDLE Reactor with Core Geometry Variations
Authors: Widiawati Nina , Su’ud Zaki , Irwanto Dwi , Permana Sidik , Sekimoto Hiroshi
Published: May 2020

Lead208-Bismuth Eutectic (LBE)- cooled reactor is one of the Generation IV reactors. The fourth-generation has several objectives: economic competitiveness, inherent safety, minimize radioactive waste, and non-proliferation. Modified CANDLE burnup scheme is one solution to fulfil these objectives. The scheme does not need fuel enrichment and reprocessing Pu from LWR. Lead208-Bi eutectic was employed as a coolant of the reactor due to its low neutron absorption cross-section. However, However, it is necessary for surveying the neutronic core design. In this study, we compared the core neutronic among the variations of core geometry with equal volume of Pb208-Bi eutectic-cooled Modified CANDLE reactor. The calculation is performed by PIJ and CITATION of SRACs module. The Pancake cylindrical (larger diameter) has the highest K-eff and the lowest-peaking factor among of balance and tall cylindrical.
The effect of radiation source distance to the scintillation detector based on Monte Carlo simulation
Authors: Junios  , Haryanto Freddy , Su’ud Zaki , Novitrian
Published: May 2020

The variation of the source distance to the detector causes a change in the count value. The aims were to study the effect of source distance variation to a detector. This research simulated count value detected by the scintillator detector with a variety of distance to the radiation source using EGSNRC tutor.3 Monte Carlo. The Energy of 60Co radiation source was modeled monoenergetic, so energies 1.17 MeV and 1.33 MeV are handled separately. The geometry of this source was assumed to be the point source. The simulated medium was divided into three regions, vacuum, scintillation detector, and vacuum. The range of detector distance variated from 5 to 9.5 cm from the source and used 109 particles. The cut-off Energy for electrons 0.512 MeV and photons 0.01 MeV. The output score energy deposited in the scintillation detector. The count value for each region was analyzed and compared. The changes of distance from 5 cm to (5.5, 7.5, 8.5, and 9.5) caused an increase of a count in the Compton area of 5.1%, 27.1%, 35.9%, and 44.6%, respectively. While in the photopeak area there was a decrease of 2.7%, 12.2%, 15.8%, and 19.0%, respectively. There was a change in count value on the distance variation caused by the quantity of source changed. The detector captures less quantity in the photopeak area.
Study of Modified CANDLE Burnup Scheme In A Helium Cooled Fast Reactor Using Uranium-Plutonium Nitride
Authors: Syahputra T S , Razak Abdul , Su’ud Zaki
Published: May 2020

The startup strategies for neutronic analysis Gas-Cooled Fast Reactors with scheme Modified CANDLE have been investigated. This research used natural uranium and spent fuel PWR in the starter core. The reactor power level was set at case 800 MWth, 900 MWth, and 1000 MWth, while the fuel fraction was varied at 50%, 55%, 60%, and 65%. The calculation was performed by using SRAC-CITATION system codes, with two-dimensional R-Z cylindrical cell models. In this Modified CANDLE burnup scheme start-up strategy, the active core was divided into ten regions (region-1 until region-10) with similar volume in the axial direction and two regions in the radial direction. The fresh fuel of natural Uranium was initially put in region-1 while another was filled with a mixture of spent fuel PWR and natural Uranium. After each cycle of burnup, defined by 10 years, the fuel from region-1 was shifted to region-2, and the fuel from region-2 was shifted to region-3. This was done consecutively until all the regions have been refueling while region 1 is refilled with natural uranium fuel. An optimum design was achieved in the reactor by 60% inner and 65% outer fuel fraction for case 800 MWt. The ratios of a peak to average power density were 1.37, with power density of 187.43 W/cc.
Study on the Effects of Enrichment and Fraction of Coated Fuel Particles on Fissile Utilization of 100 MWt Prismatic-type of High Temperature Gas Reactor
Authors: Pratama Ayu Lia , Irwanto Dwi
Published: May 2020

High Temperature Gas-cooled Reactor (HTGR) is one of Generation-IV reactor technology that has graphite moderate, Helium gas-cooled, and Coated Fuel Particle (CFP) layered by Tristructural-Isotropic (TRISO). The HTGR has an outlet temperature of around 1000°C that can be utilized for many co-generation processes other than to generate electricity. Due to characteristics of the CFP and TRISO, utilization of fissile material during reactor operation becomes important. This study aims to analyze the effects of enrichment and fraction of CFP on the fissile utilization of 100 MWt HTGR for two different fuels; UO2 and (Th-U)O2. Fissile enrichment is analyzed from 1-20% while the fraction of CFP from 10-60%. Using SRAC2006 code and JENDL-4.0 as nuclear data library, calculation and analysis are performed to find the optimal values of several important neutronic parameters.
An Optimization Method for Measurement Matrix Based on Double Decomposition
Authors: Mao Zhaoyang , Li Lan
Published: May 2020

This paper introduces a novel method of measurement matrix in compressed sensing. In order to overcome the difficulties associated with coherence of measurement matrix, we propose double optimization methods by eigenvalue decomposition and singular value decomposition under mild conditions. An efficient algorithm (SVD-EIG) is used to recover sparse inputs from the optimized measurement matrix, based on the adaptation of the optimized matrix by eigenvalue decomposition. Lastly, compared with the other methods as the same sampling rate, we demonstrate through simulations that SVD-EIG algorithm can improve accuracy and probability of the reconstruction.
Development of Thin Film Thermocouple Test System for Transient Temperature Measurement
Authors: Xi Zhu , Wanqing An , Chang Liu , Xiaoyuan Yang , Xinming Su , Yan Zhou , Zhenwei Li , Zeyuan Liu
Published: May 2020

In order to achieve accurate temperature measurement in a fast temperature change environment, a set of thin film thermocouple test system for transient temperature measurement is designed and developed. The system consists of cold junction compensation and data collector. The temperature of the film thermocouple can be obtained in real time through the upper acquisition software. The hardware composition and software design of the thin film thermocouple test system are given. The data acquisition terminal and coordinator program are designed to control the temperature signal of the MAX31855 to collect the sensor, realizing the real-time transmission of temperature data between the sensor and the computer. In order to verify the actual application effect of the system, the matching, stability and reliability of the temperature acquisition system and monitoring software, the FLUKE-9144 dry calibration furnace was selected as the heat source for the temperature test. The test results show that the system has fast acquisition speed, high measurement accuracy and good temperature stability.
Overview of the Development of Rotary Steerable Systems
Authors: Li Fei , Ma Xueying
Published: May 2020

Rotary steerable system remains the development focus of current drilling technology. It is essential for China’s unconventional Oil and Gas development. This paper outlines the research and development history, classification, development status of the rotary steerable system, and summarizes the advantages and disadvantages of different systems. Moreover, the prospects of the intelligent RSS technology is explored, and the outlook for the future development of the steerable drilling technology is presented.
A novel coplanar system with a minimal anisotropic effect
Authors: Zhang Miaoyu , Wu Jie , Yanping Liu
Published: May 2020

To obtain the response of the novel coplanar system, we use an analytic method to solve horizontal component of electromagnetic field in the anisotropic stratigraphic model by introducing the magnetic Hertz vector and the magnetic Hertz scalar from Maxwell equations. This paper examines anisotropic response characteristics between novel coplanar system and traditional coplanar system. The negative response area of the proposed coplanar system is decreased. Compared this with traditional coplanar system, the anisotropic effects have the same trend; the affected amplitude of novel coplanar system is far less than that of the traditional coplanar system. The results of experiments demonstrate the superiority of the proposed coplanar system.
Study on acoustic transmission characteristics of BHA in directional well
Authors: Xie Haiming , Zhou Jing , Zhang Peifen
Published: May 2020

Acoustic telemetry technology while drilling may effectively solve the practical and speed bottleneck of downhole information transmission, but its channel characteristics are subject to the influence of drill string structure in the channel. According to the requirements of reservoir exploitation and drilling technology, the directional well technology is becoming more complex, and the changeable bottom hole assembly (BHA) in the well causes the aperiodicity of acoustic channel. Through the modeling and analysis of BHA under different drilling technology, the characteristics of various aperiodic channels are obtained, and compared with the characteristics of ideal periodic channels, the acoustic transmission characteristics of drill string in directional well are obtained. The aperiodicity brought by BHA makes the high frequency section of the channel seriously attenuated, so the number of aperiodic drilling tools used in the acoustic remote transmission channel needs to be strictly controlled. It can be excluded from the channel if necessary.
Research on Analog Signal Source of Gamma Ray Spectrum Logging Technology
Authors: Tang Jun , Li Yiying , He Jia , Wang Simeng , Wang Hui , Zhang Chaoyang
Published: May 2020

Gamma ray spectrum logging tool acquires reservoir information by detecting gamma ray from formation. It has strict requirements for preservation and use, which is not convenient for college teaching. This paper introduces the design of an analog signal source for gamma ray spectrum logging tool, which generates random number based acceptance-rejection method. These random numbers are converted into electronic pulse signal by data acquisition system. It can simulate the electric pulse signal obtained from gamma ray through stratum. The statistical law of energy spectrum from simulation signal source accords with the probability distribution law of pulse signal generated gamma ray from formation. The analog signal source of gamma ray spectrum logging tool can generate simulation gamma ray logging signal without formation model and radiation source, which is of great value for efficient teaching.
Distribution Characteristics and Edge Detection of Electromagnetic Field in Two Beds Formation Based on Analytical Solution
Authors: Wu Jie , Li Ye
Published: May 2020

After decades of development of the Chinese petroleum industry, complex oil and gas reservoirs have become the main battlefield for oil and gas field detection and development, which pose severe challenges to geosteering drilling technology that uses integrated logging and conventional logging-while-drilling tools to locate and predict formation interfaces. Based on the developed software for the distribution of forward and lateral detection electromagnetic fields, this paper calculates and analyzes the distribution characteristics of electromagnetic fields at different distances in front, and studies the lateral detection characteristics based on the half-coil of the electric field. The results show that the influence of boundary on the field is revealed according to the distribution characteristics of electromagnetic fields at different distances in front. The 1-3m receiving-transmitting short-pitch half-coil have approximately the same edge detection distance, and when the frequency is less than 20 kHz, the edge detection distance is more than 30m in two beds formation of 0.01S/m and 1.0S/m.
Borehole transient electromagnetic array based relative attitude determination for relief well drilling
Authors: Ling Yang , Bo Dang , Changzan Liu , Linkang Xu , Zhiping Ren , Ruirong Dang
Published: May 2020

Drilling relief well is one of the most effective way to control blowout well at present. In order to improve the connection rate, the relief well needs to trace a short distance and then gradually approaches the accident well, where the relative space attitude determination of relief well and blowout well is the key to improve the drilling efficiency. In this paper, a symmetry multi-coil array-based borehole transient electromagnetic (TEM) system for relative attitude determination of relief well drilling is presented. On the basis of the borehole TEM theory, the multi-coil array weighting is applied to improve the detection performance in the case that the blowout well is parallel to the relief well. Moreover, in order to determine the relative attitude, a symmetrical borehole TEM array structure is proposed for the short-range detection. Experiments were conducted and the results demonstrate the effectiveness of the proposed method for improving the short-range detection performance, which would offer significant information for the tracing phase of relief well drilling.
Radiation Characteristics Test of FOG Circuit Magnetic Field
Authors: Lu Jun , Guo Zhirui , Liu Lei
Published: May 2020

Aiming at the magnetic field issue in the engineering application of fiber optic gyroscope (FOG), this paper explores the distribution law of magnetic field generated by the internal circuit of gyroscope and builds an electromagnetic field distribution scanning system to complete the test. The experimental results show that the overall radiation of FOG circuit magnetic field is low, and the front circuit radiation intensity is higher than that of bottom circuit. The front radiation is strongest at 8.76MHz, approximately 0.01mGs. It is of referential significance for the study of FOG magnetic sensitivity.
Exploration of Teaching Reform of Computer Network Practice Course
Authors: Wang Jiong , Zhang Hua , Ruan Zhiqiang , Wu Zhengyuan , Xu Ge
Published: May 2020

With the vigorous development of digital and network technology in China, computer and it’s technology have been widely used in various industries. Therefore, information technology has become increasingly important in today’s society. However, there are still many shortcomings in computer teaching in China, and reforms and improvements are urgently needed to give full play to the important role of computer technology. The research focuses on the following reforms of computer network practice course teaching reform.
Research on Network APT Attack Intrusion Detection Technology Based on Machine Learning Algorithm
Authors: Meng Qingchuan , Yang Yang , Wu Fengzhi , Chen Xiang , Chen Xiaoming
Published: May 2020

The attack frequency of network advanced persistent threat (APT) is more and more higher, which seriously endangers the network security. In order to obtain high accuracy of network APT attack intrusion detection results, aiming at the limitations of current network APT attack intrusion detection model, a network APT attack intrusion detection model based on machine learning algorithm is proposed. A “one-to-one” network APT attack intrusion detection classifier is built through a neutral and excellent support vector mechanism of machine learning algorithm, and the current standard network APT attack intrusion detection database is adopted to verify the validity of the model. The accuracy of network APT attack intrusion detection is over 95%, and the detection error is far lower than the actual application range. It can be used in the actual network security management.
Digital Signal Processing Optimization Algorithm for Terahertz Communication Based on Short Convolution Iterative Algorithm and Adaptive Blind Equalization Algorithm
Authors: Deng Dingsheng
Published: May 2020

This paper systematically studies the crosstalk problem caused by the low parallelization rate and tail-to-back tailing in the high-speed digital signal parallel processing in terahertz communication. First, in order to improve the parallelization rate in system application, a high-speed digital signal in the network is filtered in parallel based on a short convolution iterative algorithm for the input signal. Second, an adaptive blind equalization algorithm is proposed to solve the problem crosstalk is used to restore the original signal. Finally, the effectiveness of the equalization algorithm is verified by MATLAB, and the designed algorithm is implemented by Labview simulation software. The effectiveness of the designed algorithm is verified by simulation analysis. The high-speed signal after parallel filtering and equalization can restore the information of the original signal well.
ENSO prediction based on Long Short-Term Memory (LSTM)
Authors: Xiaoqun Cao , Yanan Guo , Bainian Liu , Kecheng Peng , Guangjie Wang , Mei Gao
Published: May 2020

El Niño-Southern Oscillation (ENSO), as a global climate event with cyclical characteristics, often causes global climate anomalies and produces non-negligible economic and social impacts. Therefore, the prediction and research of ENSO events are important for understanding and solving global climate change issues. It has important scientific and practical significance. Previous research on ENSO events mainly used traditional statistical analysis and numerical simulation methods. This study explores the use of deep learning to improve the accuracy of El Niño-Southern Oscillation (ENSO) prediction. Based on long-term and short-term memory neural networks, the time series of meteorological and marine elements were analyzed. In the meantime, the sea surface temperatures (SST) and sea level pressure were predicted to calculate the Southern Oscillation Index (SOI) to reflect the ENSO phenomenon. Finally, this article takes the Niño3.4 regional data from the National Centers for Environmental Prediction (NCEP) dataset as an example, and uses the model proposed in this paper to compare with traditional statistical regression methods. The results show that the Long Short-Term Memory (LSTM) has a good effect in the prediction of ENSO events, and has certain scientific significance and practical value for the prediction of ENSO events.
Research and Design of Hybrid Scheduling Algorithm Based on LIN Bus
Authors: Liang Zhanwei , Shi Hongyu , Yan Hao , Ma Dongmei , Li Jie
Published: May 2020

In the LIN(Local Interconnect Network) bus communication transmission, there is a problem of data transmission delay in the process of sending messages by the master-slave node ECU(Electronic Control Unit).Aiming at this kind of delay problem, this paper analyzes the characteristics of static scheduling and dynamic scheduling algorithm of LIN bus, optimizes the scheduling strategy of LIN bus message, and proposes a hybrid scheduling algorithm based on time slice scheduling. At the same time, the simulation model of LIN bus master-slave node message transmission is established, and the simulation experiment verification platform of LIN bus hardware-in-the-loop is built. It is verified that the algorithm reduces the delay by about 30%.
KSR: Knowledge-based Sequential News Recommendation System
Authors: Bai Jiameng , Huang Xin , Li Min , Peng Jia
Published: May 2020

With the popularity of the Internet, some online news reading habits have gradually replaced traditional media devices. People can see a variety of news on mobile phones or web pages. The overloaded information makes it impossible for users to quickly get the news they want to see, so the existence of a news recommendation system is necessary. However, unlike other fields, the recommendation of news is time-sensitive, and the problem of sparse data makes traditional collaborative filtering algorithms invalid. There are many entities in the news, and the knowledge graph is a collection of a large number of entities. In this paper, we propose a KSR model (Knowledge-based Sequential Recommendation) which uses the knowledge graph as side information to enrich the feature representation of the news to calculate the user’s probability to click the forecasted news. KSR uses the knowledge graph to represent the entities in the news and uses a recurrent neural network to capture the sequential relationships in the news data to enrich the feature representation of the news. Because the different news that user has clicked have different relations with the news to be predicted, the attention model is introduced to calculate the weights. Finally, we conduct experiments on the existing dataset and results prove the efficacy of KSR over several baselines. Different contrast experiments also prove the effectiveness of each module of the model.
The Cognitive Communication based Anti-jamming Method for UAV Swarm Communication
Authors: Wu Jian , Liu Rang , Zhao Sen
Published: May 2020

The communication environment of intelligent UAV swarm is complex and easy to be interfered by various electromagnetic signals. An anti-jamming method of UAV swarm communication based on cognitive communication is proposed to realize the communication networking function of UAV swarm in certain interference environment. The main approaches include spectrum sensing in electromagnetic environment, anti-jamming based intelligent decision making, and series typical anti-jamming techniques such as adaptive interference and signal separation, dynamic spectrum access, high reliability waveform enabled.
Research on Numerically Solving the Inverse Problem Based on L1 Norm
Authors: Yanan Guo , Xiaoqun Cao , Bainian Liu , Kecheng Peng , Guangjie Wang , Mei Gao
Published: May 2020

In this paper, the numerical solution method based on L1 norm for inverse problem is studied. First, according to the theory of the L1 norm and the characteristics of the problem to be solved, a cost function is constructed. Further, for complex parameter estimation problems and derivative discontinuities, the regularization method is used to construct the cost function and the Huber function is used in the derivative discontinuity. Finally, the problem is solved numerically by the semi-smooth Newton method. The experimental results show that the method based on L1 norm is an effective method under the interference of non-Gaussian noises. For the parameter estimation of complex models, the results based on the L1 norm method are very closer to the real parameters when there is impulse noise. For parameter estimation under non-Gaussian noise, the L1 norm estimation method has significant advantages over the L2 norm method.
Review of Crop Disease and Pest Image Recognition Technology
Authors: Jia Shaopeng , Gao Hongju
Published: May 2020

Throughout the history of agricultural development, crop diseases and pests have been one of the main obstacles hindering the development of agricultural economy, which not only caused irreversible economic losses to farmers, but also hindered the development of economic and social. The crop pets and diseases identification system based on digital image processing technology has the characteristics of fast, accurate and real-time, which can assist farmers to take effective control measures in time. In this paper, we have done some review on different digital image processing techniques to detect the plant diseases. We compared traditional machine learning and deep learning and discussed the future research trends and directions .
Post-job Data Analysis by Python for a Miniature Recorder in Drilling Motors
Authors: Li Fei , Song Haolan
Published: May 2020

A vibration recorder has been deployed to capture the dynamics data of drilling motors for their operation and health evaluation. The recorder is usually inserted inside the rotor catcher of a conventional drilling motor in such a way that no extra length is introduced to the planned bottom hole assembly (BHA). The recorder can log data over the full operation cycle of a drilling motor, including vibration during surface activities and downhole operation. A post-job data analyzer was specifically designed based on Python. The analyzer processes the recorded data and generates statistics, time plots, and the various statistical plots such as histograms. These statistics and plots help the operators and maintenance technicians to gain insights into the motor operation and performance. The analyzer can provide adequate information on a drilling motor to asset owners for maintenance and operation optimization without analysis training or qualification from operators.