bluuebunny/crossref_metadata_2025 huggingface dataset:
miR-155 promotes T reg cell development by safeguarding medullary thymic epithelial cell maturation
Authors: Dong Jiayi , Warner Lindsey M. , Lin Ling-Li , Chen Mei-Chi , O'Connell Ryan M. , Lu Li-Fan
Published: October 2020

During thymocyte development, medullary thymic epithelial cells (mTECs) provide appropriate instructive cues in the thymic microenvironment for not only negative selection but also the generation of regulatory T (T reg) cells. Here, we identify that miR-155, a microRNA whose expression in T reg cells has previously been shown to be crucial for their development and homeostasis, also contributes to thymic T reg (tT reg) cell differentiation by promoting mTEC maturation. Mechanistically, we show that RANKL stimulation induces expression of miR-155 to safeguard the thymic medulla through targeting multiple known and previously uncharacterized molecules within the TGFβ signaling pathway, which is recognized for its role in restricting the maturation and expansion of mTECs. Our work uncovers a miR-155–TGFβ axis in the thymic medulla to determine mTEC maturity and, consequently, the quantity of tT reg cells and suggests that miR-155 ensures proper tT reg cell development in both cell-intrinsic and -extrinsic manners.
Type I interferon signaling mediates Mycobacterium tuberculosis–induced macrophage death
Authors: Zhang Li , Jiang Xiuju , Pfau Daniel , Ling Yan , Nathan Carl F.
Published: October 2020

Macrophages help defend the host against Mycobacterium tuberculosis (Mtb), the major cause of tuberculosis (TB). Once phagocytized, Mtb resists killing by macrophages, replicates inside them, and leads to their death, releasing Mtb that can infect other cells. We found that the death of Mtb-infected mouse macrophages in vitro does not appear to proceed by a currently known pathway. Through genome-wide CRISPR-Cas9 screening, we identified a critical role for autocrine or paracrine signaling by macrophage-derived type I IFNs in the death of Mtb-infected macrophages in vitro, and blockade of type I IFN signaling augmented the effect of rifampin, a first-line TB drug, in Mtb-infected mice. Further definition of the pathway of type I IFN–mediated macrophage death may allow for host-directed therapy of TB that is more selective than systemic blockade of type I IFN signaling.
The T cell CD6 receptor operates a multitask signalosome with opposite functions in T cell activation
Authors: Mori Daiki , Grégoire Claude , Voisinne Guillaume , Celis-Gutierrez Javier , Aussel Rudy , Girard Laura , Camus Mylène , Marcellin Marlène , Argenty Jérémy , Burlet-Schiltz Odile , Fiore Frédéric , Gonzalez de Peredo Anne , Malissen Marie , Roncagalli Romain , Malissen Bernard
Published: October 2020

To determine the respective contribution of the LAT transmembrane adaptor and CD5 and CD6 transmembrane receptors to early TCR signal propagation, diversification, and termination, we describe a CRISPR/Cas9–based platform that uses primary mouse T cells and permits establishment of the composition of their LAT, CD5, and CD6 signalosomes in only 4 mo using quantitative mass spectrometry. We confirmed that positive and negative functions can be solely assigned to the LAT and CD5 signalosomes, respectively. In contrast, the TCR-inducible CD6 signalosome comprised both positive (SLP-76, ZAP70, VAV1) and negative (UBASH3A/STS-2) regulators of T cell activation. Moreover, CD6 associated independently of TCR engagement to proteins that support its implication in inflammatory pathologies necessitating T cell transendothelial migration. The multifaceted role of CD6 unveiled here accounts for past difficulties in classifying it as a coinhibitor or costimulator. Congruent with our identification of UBASH3A within the CD6 signalosome and the view that CD6 constitutes a promising target for autoimmune disease treatment, single-nucleotide polymorphisms associated with human autoimmune diseases have been found in the Cd6 and Ubash3a genes.
Covariance of the extended holonomy
Authors: Gambini Rodolfo , Pullin Jorge , Skirzewski Aureliano
Published: October 2020

It has been pointed out that the holonomy of generic extended loops is not gauge covariant. We show how to define a family of extended loops for which previous criticism does not apply. We also give sufficient conditions that extended loops must satisfy in order to yield covariant holonomies. This makes a quantum representation for Yang–Mills theories and gravity based on extended loops viable.
Tikhonov-like methods with inexact minimization for solving linear ill-posed problems
Authors: Margotti Fábio , Rabelo Joel
Published: October 2020

In this article we propose and study the properties of three distinct algorithms for obtaining stable approximate solutions for systems of ill-posed equations, modeled by linear operators acting between Hilbert spaces. Based on Tikhonov-like methods with uniformly convex penalty terms, we develop new versions with inexact minimization of both one step and iterated-Tikhonov methods. For the case of one step methods, we propose two distinct algorithms, one based in a priori and one based in a posteriori choice of the regularization parameter. Convergence and stability properties are provided, as well as optimal convergence rates (under appropriate source conditions). The third algorithm is based in a variant of the iterated-Tikhonov method with a posteriori choice of the sequence of penalization parameters. For this algorithm, we prove stability for noisy data and the regularization property.
Organic electronics Axon-Hillock neuromorphic circuit: towards biologically compatible, and physically flexible, integrate-and-fire spiking neural networks
Authors: Mirshojaeian Hosseini Mohammad Javad , Donati Elisa , Yokota Tomoyuki , Lee Sunghoon , Indiveri Giacomo , Someya Takao , Nawrocki Robert A
Published: October 2020

Spiking neural networks (SNNs) have emerged as a promising computational paradigm to emulate the features of natural neural tissue physiology. While hardware implementations of SNNs are being conceived to emulate biological systems, they typically rely on hard and rigid silicon electronics that are not bio-compatible. In the physical, or materials realm, organic electronics offer mechanical flexibility and bio-compatibility, allowing for the construction of neural processing systems that can be directly interfaced to biological networks. This study introduces an organic electronics implementation of an Integrate-and-Fire spiking neuron based on the Axon-Hillock CMOS circuit. The circuit employs organic p-type and n-type field effective transistors and reproduces the behavior of the CMOS neuromorphic counterpart. We demonstrate its operating characteristics measuring its spike rate output as a function of its input current. We show how it properly integrates input currents and demonstrate its computing abilities in a basic current summing experiment. The static and dynamic power dissipation is calculated to be less than 0.4 and 40 µW, respectively. This is the first demonstration of the spiking Axon-Hillock neuromorphic circuit using organic materials.
Topological insulator in a hexagonal plate with droplet holes
Authors: Zhang Kai , Hong Fang , Luo Jie , Deng Zichen
Published: October 2020

In this study, we introduce a tunable topological insulator (TI) system consisting of a hexagonal aluminum plate with rotatable droplet-shaped holes to produce topologically protected edge waves (TPEWs) along a topological interface. By rotating the round plate in the unit cells to break the unit cells’ mirror symmetry while preserving C3 symmetry, a new band gap is produced from the dispersion relations’ Dirac point. A topological protection state is generated at the interface due to the valley Hall effect. We also simulate different TPEWs along disparate interface routes and further prove their robustness, which means that they are immune to the vast majority of backscattering along interfaces. We also demonstrate that TPEWs at specific frequencies can be transported to different locations in hexagonal TIs, which is an innovative technique for precise control of acoustic guidance. This study provides a new method to modulate guide waves and energy accumulation of different frequency waves in topological systems.
3D computational study of arc splitting during power interruption: the influence of metal vapor enhanced radiation on arc dynamics
Authors: Huo Jindong , Wang Yifei , Cao Yang
Published: October 2020

Arc splitting is one of the most important processes in accomplishing a power interruption by multiplying the number of voltage drops. During arc-plate interaction, the arc roots erode and vaporize the metals which significantly alters the gas composition and plasma properties, such as the radiation absorption coefficient. In this work, we perform a 3D computational study of arc splitting in a circuit breaker. In order for the study to be systematic, the metal vaporization, species transport, and radiative heat transfer are integrated into the magnetohydrodynamics modeling with some special considerations. Firstly, the simulation considers the ferromagnetic effect of steel plates. Secondly, the metal-vapor-enhanced radiation is numerically implemented by the discrete ordinate method with consideration given to the banded radiation spectrum. Thirdly, the simulation model incorporates a near-electrode layer to implement the voltage drop and imposes additional heat flux on the arc spots. The simulation results show that the metal vaporization not only influences the arc dynamics (via Stefan flow) but also enhances the local radiation intensity. Besides, due to the ferromagnetic effect, the magnetic field increases dramatically during arc splitting. However, the self-induced magnetic force has quite a different influence on the motion of sub-arcs, which prevents even and concurrent arc splitting. This simulation reveals that the magnetic-field-induced uneven splitting can be compensated by the enhanced pressure wave or externally applied transversal magnetic field. This study is expected to explore more applications in simulating arc interruption and improve the design of highly-efficient circuit breakers.
Supreme enhancement of ferromagnetism in a spontaneous-symmetry-broken 2D nanomagnet
Authors: Kar S , Nair A K , Ray S J
Published: October 2020

The ability to tune and control the magnetic phases of two-dimensional (2D) nanomagnets at room temperature is indispensable for the development of future spintronics and low-dimensional spin circuits. In this work, a first-principles-based investigation combined with a Monte Carlo simulation based on a 2D Ising model is used to investigate the electronic and magnetic behaviour of a recently discovered 2D material, Cr2Ge2Se6 over a large range of strain and electric field strength. This material offers ferromagnetic

→

antiferromagnetic and semiconductor

→

metallic phase transitions in different regimes. In the presence of strain, a colossal enhancement of the critical temperature (T

c
) is observed, from 149 K to 885 K. The application of an electric field allows a further enhancement of the T

c
to a value of 919 K, offering a supreme enhancement (~517%), compared to its natural condition. The origin of this behavior can be traced to a super-exchange interaction between the Cr and Se atoms and the intrinsic magnetic anisotropy of Cr2Ge2Se6. The presence of external stimuli engenders spontaneous symmetry breaking with an enhanced magnetic moment (~4.36

μ

B

/Cr atom), a significant intrinsic spin polarisation (~100%) in a half-metallic regime, and a very high critical temperature. The insights of the current investigation could be useful for future developments in multi-stimuli-assisted room-temperature ferromagnetism and electronic phase control, which are of great significance for future magneto-electronic applications.
Thermo-mechanical modeling and characterization of three-phase shape memory alloy hybrid composites
Authors: Yu Haifan , Lu Linjun , Qiao Pizhong
Published: October 2020

The thermo-mechanical properties of shape memory alloy hybrid composites (SMAHCs) are characterized, and their three-phase constitutive relationship in the form of a lamina embedded with shape memory alloy (SMA) wires is established by micromechanics. Considering large beam deflection, a theoretical bending model of SMAHC beams with different fiber volume fractions and arbitrary ply schemes is proposed. The Runge–Kutta method is employed to solve the nonlinear ordinary differential equations, and the quantitative relations of curvature, rotation and deflection under thermal load are obtained from the model by directly using the original three-phase material parameters without the need of the experimental measurement in single layer. The SMAHC beams with different fiber orientation, number of layers, and volume fraction of SMA are fabricated, and their thermo-mechanical behavior is experimentally evaluated. Good agreements between the theoretical predictions and experimental results demonstrate that the proposed model is capable of predicting the thermo-mechanical behavior of three-phase SMAHC beams. The generic model developed can be used as an analytical tool in design analysis and optimization of SMAHC structures for effective shape, tracking, and vibration control.
Synergistic effect of ion chelating agent and inorganic compound on pore structure, mechanical and self-healing performance of cement-based materials
Authors: Gu Shunjie , Wang Ruiyang , He Peng , Du Wei , Yu Jianying
Published: October 2020

Ion chelating agent can effectively improve the self-healing of concrete. In order to further enhance the self-healing ability of cement-based materials, ion chelating agent and inorganic compounds (sodium silicate and sodium bicarbonate) were used together in this paper. Pore size distribution, mechanical and self-healing performance of the mortars with ion chelating agent and inorganic compounds were investigated. The results showed that harmful pores (pore diameter above 0.1 μm) of the mortar was reduced and mechanical properties was increased by adding ion chelating agent and inorganic compounds, especially mortar mixed with 0.50% ion chelating agent and 0.25% sodium silicate had the least harmful pores and the highest compressive strength and flexural strength. Moreover, the self-healing properties of mortars were significantly improved by combination of ion chelating agent and inorganic compound. Especially for mortar mixed with 0.5% ion chelating agent and 0.5% sodium silicate, the relative water permeability coefficient decreased to 0 after curing for 28 d, and the cracks with width of 0.31 mm and 0.46 mm could be completely closed after curing for 3 d and 28 d respectively. SEM observation showed that the calcium carbonate, ettringite and calcium carbonate were covered by CSH gel in the cracks and interior of the mortar mixed with ion chelating agent and sodium silicate, which proved that the ion chelating agent and sodium silicate had synergistic effect on the self-healing properties of cement-based materials.
X-ray standing wave studies of molecular adsorption: why coherent fractions matter
Authors: Woodruff D P , Duncan D A
Published: October 2020

The normal incidence x-ray standing wave (NIXSW) technique is the primary source of quantitative experimental information on the adsorption height of many near-planar molecules on metal surfaces, of relevance to organic electronics. The technique yields two structural parameters, the coherent position and the coherent fraction. For high values of the coherent fraction the coherent position can be related directly to the adsorption height, but because the coherent fraction is effectively an order parameter, low values of this parameter are often attributed to partial disorder. It is certainly true that in depositing these large molecules on a surface it is very challenging to produce a perfectly ordered surface. However, is the type of disorder that is likely to occur able to account for no other effect on measured NIXSW data than a lowering of the coherent fraction? Here we show, by considering a wide range of possible types of ‘disorder’, that in almost all such situations it is improbable that the coherent positions associated with very low coherent fractions actually provide a reliable measure of the adsorption height of the ordered component, as is often assumed to be the case. As such, presentations of NIXSW data that only consider coherent position values are likely to be extremely misleading, and provide an unreliable benchmark for detailed understanding of these interfaces.
The Tsinghua University-Ma Huateng Telescopes for Survey: Overview and Performance of the System
Authors: Zhang Ji-Cheng , Wang Xiao-Feng , Mo Jun , Xi Gao-Bo , Lin Jie , Jiang Xiao-Jun , Zhang Xiao-Ming , Li Wen-Xiong , Yan Sheng-Yu , Chen Zhi-Hao , Hu Lei , Li Xue , Lin Wei-Li , Lin Han , Miao Cheng , Rui Li-Ming , Sai Han-Na , Xiang Dan-Feng , Zhang Xing-Han
Published: October 2020

Over the past decade, time-domain astronomy in optical bands has developed rapidly with the operations of some wide-field survey facilities. However, most of these surveys are conducted with only a single band, and simultaneous color information is usually unavailable for the objects monitored during the survey. Here we present introductions to the system of Tsinghua University-Ma Huateng Telescopes for Survey (TMTS), which consists of an array of four optical telescopes installed on a single equatorial mount. Such a system is designed to get multiband photometry simultaneously for stars and transients discovered during the survey. The optics of each telescope is a modified Hamilton-Newtonian system, covering the wavelengths from 400 to 900 nm, with a field of view (FoV) of about 4.5 deg2 and a plate scale of 1.″86 pixel−1 when combining with a 4K × 4K QHY4040 CMOS detector. The TMTS system can have a FoV of about 9 deg2 when monitoring the sky with two bands (i.e., SDSS g and r filters) at the same time, and a maximum FoV of ∼18 deg2 when four telescopes monitor different sky areas in monochromatic filter mode. For an exposure time of 60 s, the average 3σ detection limit of the TMTS system can reach at ∼19.4 mag in Luminous filter and at ∼18.7 mag in SDSS r filter. The preliminary discovery obtained during the first few months’ survey is briefly discussed. As this telescope array is located at the Xinglong Observatory of NAOC, it can have an excellent synergy with the spectroscopic survey by the LAMOST (with a FoV of about 20 deg2) at the same site, which will benefit the studies of stellar and binary physics besides the transient sciences.
Observational signatures of close binaries of supermassive black holes in active galactic nuclei
Authors: Wang Jian-Min , Li Yan-Rong
Published: October 2020

Inspired by the General Relativity for many decades, experimental physicists and astronomers have a solid dream to detect gravitational waves (GWs) from mergers of black holes, which came true until the excellent performance of the Laser Interferometer Gravitational-Wave Observatory (LIGO) at hundreds Hz. Nano-Hz GWs are expected to be radiated by close-binaries of supermassive black holes (CB-SMBHs; defined as those with separations less than ∼0.1 pc) formed during galaxy mergers and detected through the Pulsar Timing Array (PTA) technique. As of the writing, there remains no nano-Hz GWs detection. Searching for CB-SMBHs is also observationally elusive though there exist a number of possible candidates. In this review, we focus on observational signatures of CB-SMBHs from theoretic expectations, simulations and observations. These signatures appear in energy distributions of multiwavelength continuum, long term variations of continuum, jet morphology, reverberation delay maps and spectroastrometry of broad emission lines, AGN type transitions between type-1 and type-2 (changing-look), and gaseous dynamics of circumbinary disks, etc. Unlike hundred-Hz GWs from stellar mass black hole binaries, the waveform chirping of nano-Hz GWs is too slow to detect in a reasonable human timescale. We have to resort to electromagnetic observations to measure orbital parameters of CB-SMBHs to test nano-Hz GW properties. Reverberation mapping is a powerful tool for probing kinematics and geometry of ionized gas in the gravitational well of SMBHs (single or binary) and therefore provides a potential way to determine orbital parameters of CB-SMBHs. In particular, a combination of reverberation mapping with spectroastrometry (realized at the Very Large Telescope Interferometer) will further reinforce this capability. The Atacama Large Millimeter/submillimeter Array (ALMA) and the forthcoming Square Kilometre Array (SKA) are suggested to reveal dynamics of circumbinary disks through molecular emission lines.
The youngest X-ray binaries
Authors: Li Xiang-Dong
Published: October 2020

Several X-ray binaries (XRBs) have been identified to be associated with supernova remnants (SNRs). Because of the short lifetimes of SNRs, this leaves them to be the youngest known XRBs. This small group of binaries provides valuable information on the formation of compact stars under the framework of massive binary evolution. In this paper we review the observational characteristics of these youngest XRBs and discuss their possible implications on the initial conditions of compact stars and their interaction with the companion stars.
Contact binaries at different evolutionary stages
Authors: Qian Sheng-Bang , Zhu Li-Ying , Liu Liang , Zhang Xu-Dong , Shi Xiang-Dong , He Jia-Jia , Zhang Jia
Published: October 2020

Contact binaries consist of two strongly interacting component stars where they are filling their critical Roche lobes and sharing a common envelope. Most of them are main-sequence stars, but some of them are post main-sequence systems. They are good astrophysical laboratories for studying several problems such as the merging of binary stars, evolution of the common envelope, the origin of luminous red nova outbursts and the formation of rapidly rotating single stars with possible planetary systems. A large number of contact binary candidates were detected by several photometric surveys around the world and many of them were observed by the LAMOST spectroscopic survey. Based on follow-up observations, the evolutionary states and geometrical structures of some systems were understood well. In this review, we will introduce and catalog new stellar atmospheric parameters (i.e., the effective temperature (T
eff), the gravitational acceleration (log(g)), metallicity ([Fe/H]) and radial velocity (Vr
)) for 9149 EW-type contact binaries that were obtained based on low- and medium-resolution spectroscopic surveys of LAMOST. Then we will focus on several groups of contact binary stars, i.e., marginal contact binary systems, deep and low-mass ratio contact binary stars, binary systems below the short-period limit of contact binaries and evolved contact binaries. Marginal contact binaries are at the beginning of the contact stage, while deep and low-mass ratio contact binary stars are at the final evolutionary stage of tidally locked binaries. Several statistical relations including the period-temperature relation are determined well by applying LAMOST data and their formation and evolutionary states are reviewed. The period-color relation of M-type binaries reveals that there are contact binaries below the short-period limit. Searching for and investigating contact binaries near and below this limit will help us to understand the formation of contact binary systems and a new prediction for the short-period limit is about 0.15 d. Some evolved contact binaries were detected by the LAMOST survey where both components are sub-giants or giants. They provide a good opportunity to investigate evolution of the common envelope and are the progenitors of luminous red novae like V1309 Sco.
Magnetic flux ropes in the solar corona: structure and evolution toward eruption
Authors: Liu Rui
Published: October 2020

Magnetic flux ropes are characterized by coherently twisted magnetic field lines, which are ubiquitous in magnetized plasmas. As the core structure of various eruptive phenomena in the solar atmosphere, flux ropes hold the key to understanding the physical mechanisms of solar eruptions, which impact the heliosphere and planetary atmospheres. The strongést disturbances in the Earth’s space environments are often associated with large-scale flux ropes from the Sun colliding with the Earth’s magnetosphere, leading to adverse, sometimes catastrophic, space-weather effects. However, it remains elusive as to how a flux rope forms and evolves toward eruption, and how it is structured and embedded in the ambient field. The present paper addresses these important questions by reviewing current understandings of coronal flux ropes from an observer’s perspective, with an emphasis on their structures and nascent evolution toward solar eruptions, as achieved by combining observations of both remote sensing and in-situ detection with modeling and simulation. This paper highlights an initiation mechanism for coronal mass ejections (CMEs) in which plasmoids in current sheets coalesce into a ‘seed’ flux rope whose subsequent evolution into a CME is consistent with the standard model, thereby bridging the gap between microscale and macroscale dynamics.
Overview of the LAMOST-Kepler project
Authors: Fu Jian-Ning , Cat Peter De , Zong Weikai , Frasca Antonio , Gray Richard O. , Ren An-Bin , Molenda-Żakowicz Joanna , Corbally Christopher J. , Catanzaro Giovanni , Shi Jian-Rong , Luo A-Li , Zhang Hao-Tong
Published: October 2020

The NASA Kepler mission obtained long-term high-quality photometric observations for a large number of stars in its original field of view from 2009 to 2013. To provide reliable stellar parameters in a homogeneous way, the LAMOST telescope began to carry out low-resolution spectroscopic observations for as many stars as possible in the Kepler field in 2012. By June 2018, 238 386 low-resolution spectra with SNR
g
≥ 6 had been collected for 155 623 stars in the Kepler field, enabling the determination of atmospheric parameters and radial velocities, as well as spectral classification of the target stars. This information has been used by astronomers to carry out research in various fields, including stellar pulsations and asteroseismology, exoplanets, stellar magnetic activity and flares, peculiar stars and the Milky Way, binary stars, etc. We summarize the research progress in these fields where the usage of data from the LAMOST-Kepler (LK) project has played a role. In addition, time-domain medium-resolution spectroscopic observations have been carried out for about 12 000 stars in four central plates of the Kepler field since 2018. The currently available results show that the LAMOST-Kepler medium resolution (LK-MRS) observations provide qualified data suitable for research in additional science projects including binaries, high-amplitude pulsating stars, etc. As LAMOST is continuing to collect both low- and medium-resolution spectra of stars in the Kepler field, we expect more data to be released continuously and new scientific results to appear based on the LK project data.
Analysis on the Characteristics of the Casualties Caused by Earthquake Disasters in China in Recent Years
Authors: He Ping
Published: October 2020

This paper intends to re-study the characteristics of earthquake disasters according to the 184 earthquake disaster events that occurred in mainland China from 2001 to 2016 on the basis of previous studies. Taking 184 earthquake cases as samples, a quantitative analysis of the main coupling factors of casualties caused by earthquakes is carried out to lay the foundation for establishing a more accurate casualty assessment model for earthquake disasters.
MRI Characterization of the Pore Structure Evolution by Forced Aeration during Heap Leaching
Authors: Yu Shaofeng , Gao Pengju
Published: October 2020

In spite of lots of methods in improving the performance of heap leaching, much controversy on the industrial applications remain. A relatively new and effective idea of introducing aeration to heap leaching, especially in abiotic heap leaching, may be a better way. Experiments on water content (WC) of the leaching columns employing a novel heap leaching apparatus and Magnetic Resonance Imaging (MRI) by changing aeration intensity (AI) were conducted. The results show that WC within the heap can be effectively increased which may enlarge the area of liquid-solid interface to probably improve the leaching efficiency and performance.
Landscape Design of Road Environment based on Computer
Authors: Gu Xin , Hong Tao
Published: October 2020

The environmental landscape design of the road is an important embodiment of the historical background and cultural accomplishment of a city and a region. In the computer age, environmental landscape design becomes more simple. This paper mainly describes the main principles and design ideas of computer-based road landscape design. This paper also put the idea of green design in landscape design.
Research on the Curriculum Reform of “Plant Planting Design” Based on SketchUP
Authors: Zheng Yi
Published: October 2020

With the rapid development of society, garden has become an indispensable leisure place in the city. Therefore, landscape design has become a hot professional. “Plant planting design” is the core professional course of landscape architecture specialty, which every landscape designer must learn. Plant planting design is an indispensable link in the process of landscape design, which is an important content in the process of landscape professional training. However, most engineering schools lack of teaching experience in plant planting design, which will lead to students not fully understand plant planting design. The SketchUP technology, also known as computer-aided technology, refers to the use of computers and graphics equipment to help designers perform design work, which can greatly improve people’s work efficiency and enable people to have concrete cognition of abstract things. Therefore, we must reform the course of plant planting design, which will improve students’ interest and enthusiasm, and actively use the SketchUP and other related design tools in the teaching process. First of all, this paper analyzes the problems of curriculum teaching. Then, some suggestions are put forward.
Development Characteristics and Development Technology Analysis of Low Permeability Oilfield
Authors: Zhang Nan
Published: October 2020

Oil is an important energy resource in the world. Therefore, the oil extraction efficiency will affect the social and economic development of our country, which requires us to constantly improve our own extraction technology and improve the efficiency of oil development. Although China is a country with abundant oil reserves, most of the oilfields in China are low permeability ones. There are many problems in Low permeability oilfield (hereinafter referred to as LPO), such as small porosity, low permeability, difficult production and so on. Therefore, this paper first analyzes the characteristics of LPO, such as low natural productivity, poor water absorption capacity, rapid decline after fracturing. Therefore, China has made more research on LPO, which has formed a relatively complete series of LPO production technology. Finally, this paper summarizes the current development technology of LPO in China, which will realize the economic and effective development of LPO.
New Energy Formats and Quantitative Methods
Authors: Wu Shanshan , Wu Chenrui , Tang Rui
Published: October 2020

The article mainly deduces and summarizes the definition and classification of new energy format based on the concept of energy format, combined with industry consensus and objective description. From the perspective of changes in product types, production methods, and organizational forms, they are divided into five types of new energy formats: energy format with integration of production and consumption, energy format of clean supply, vertically integrated energy format, energy format of Multi-energy complementary and energy format of the integration of information and industrialization. Aiming at the investment and employment of new business forms, construct a data processing method and give a quantitative research basis for new energy formats. It is found that from an overall point of view, the new energy format has shown a good development trend, especially the rapid development of new energy represented by wind power and photovoltaic power generation.
Classroom Environment Empirical Evaluation of the Professional English for Chemistry Based on Project-based Learning Model
Authors: Xu Xiaoshu
Published: October 2020

With the development of the education internationalization, the teaching modes of professional English are becoming more and more diversified, and Project-based learning method is one of the most powerful ones. In order to evaluate the professional English classroom environment, an effective instrument is needed. A sample of 290 students were taken from one university in Dalian, using the methods of exploratory factor analysis, Cronbach’s Alpha, correlation test of SPSS 22.0. The results indicate that most items in the instrument can be categorized into 12 factors which are internally reliable. The reliability coefficients are so high that the items in one factor have certain homogeneity. The formative evaluation and the terminal evaluation are significantly correlated and significantly influenced each other. Thus, in the project-based professional English for Chemistry classroom, the learning behaviors and interpersonal support should be fully focused on, in order to optimize students’ ways and the processes of classroom participation, enhance the learning effects and learning satisfaction.
Analysis on the Survivability of Equipment Support System of Non War Military Operations Based on Operational Efficiency
Authors: Qi Ou , Zhang Lei , Shi Wenhua , Wang Yanli
Published: October 2020

In the process of carrying out the mission, the equipment support system of non war military operations will be interfered and destroyed by various kinds. How to ensure the normal operation of the equipment support system of non war military operations under the interference and destruction is an important factor that restricts the effectiveness of our military non war military operations. Therefore, scholars at home and abroad have carried out a lot of research.
Investigation on Multi-level Extensive Evaluation of the Safety Risk of Tank Guns’ Live Shooting
Authors: Song Chao , Luo Jianhua , Jia Yizhuo
Published: October 2020

Adopting a systematic perspective to create the safety management evaluation of the index system of tank guns’ live shooting, which formed from three elements, for example, people, tools, and management. Next, an extensive evaluation approach used to install an evaluation model for safety management and more impartial entropy utilized. Later, the value method used to estimate the weight of every layer of indicators, and then the evaluation model is employed to a standard case investigation. Hence, the application outcomes prove the practicability of the evaluation model.
Theoretical investigation of incomplete ionization of dopants effect on p+nn-n+ 4H-SiC IMPATT diode
Authors: Chen Qing , He Wei , Cheng Cankun , Xue Yanxia
Published: October 2020

The effect of incomplete ionization of dopants on p+nn-n+ 4H silicon carbide (4H-SiC) impact-ionization-avalanche-transit-time (IMPATT) diodes has been investigated. Breakdown voltage, avalanche region width, DC to RF conversion efficiency and RF output power of the 4H-SiC IMPATT device with incomplete and complete ionization are given at different temperatures. Theoretical analysis reveals that the influence of the incomplete ionization of dopants on the performance of the p+nn-n+ 4H-SiC IMPATT devices cannot be ignored.
Modeling and Calculation of Coupled Heat Transfer for Heating Process of Perforating Test Tool
Authors: Hou Yongqiang , Jia Guangzheng
Published: October 2020

The perforating bullet detection experimental device is used to simulate the downhole high-temperature and high-pressure environment in which the perforating bullet performance is test. The perforating test tool is inside liquid-filled cylindrical wellbore cavity that is heated by heating wellbore wall with natural convection heat transfer. A mathematical model for unsteady heat-fluid-solid coupling heat transfer between the liquid in the wellbore cavity and the perforating test tool was established. The projection method is used to numerically solve the mathematical model, and the results of the dynamic heating evolution process of the perforation experimental device are calculated. The internal flow field and temperature field of the perforation experimental device with and without the perforating test tool in the wellbore are analyzed. Through the calculation and analysis results, it is found that the perforating test tool inside the simulated wellbore cavity has a greater influence on the flow field and temperature field.
Research on Automatic Cable Monitoring System Based on Vibration Fibber Optic Sensor Technology
Authors: Feng Yuan , Bai Fan , Zhu Yong , Cao Zhuobin , Ge Zhifeng , Fei Wu , Guo Pengcheng
Published: October 2020

To ensure the safety of power cables, temperature monitoring of power cables is critical. In view of the shortcomings of some optical fibre measurement products, a long-distance distributed optical fibre sensor is proposed, which has the advantages of high measurement sensitivity, fast response speed, low false alarm rate, large measurement length, and stable operation. The distributed optical fibre vibration sensing measurement equipment is used to monitor the vibration signals along the cable in real time, and the signal changes before and after the breakdown fault are visually displayed by the patio-temporal spectrum diagram, and the vibration signal of the breakdown point is analysed in time and frequency. The performance of the system was tested, and the experiment verified that the temperature measurement accuracy error range of the temperature measurement system is about ± 5 °C, and it has good stability. At the same time, the positioning accuracy is very high, and the fault point can be accurately located. This can avoid the occurrence of cable accidents.
Research on Typical System Platform of Mechanical and Electrical Equipment Based on Embedded Technology
Authors: Zhang Chenyu
Published: October 2020

Embedded technology is a new development of computer technology and has a wide range of applications and development prospects. The application of embedded technology has greatly promoted the development of the field of electromechanical control and improved the performance of electromechanical control equipment. Aiming at the problem that the mechanical and electrical products have low technical content and cannot meet the requirements of modern engineering, this paper uses DM642 as the core to build an embedded electromechanical device composed of video / audio signal processing modules, memory expansion modules, external interface modules, etc. A typical system platform proposes a motion detection method and an abnormal sound recognition algorithm based on the improved frame difference method. This paper introduces the composition of the system platform in detail, and also studies the application scheme of the embedded operating system for electromechanical equipment. Using this system platform can greatly improve the digitization, information and automation of mechanical and electrical products, and provide reference value for the technological upgrading of traditional manufacturing.
Ultimate Strength Analysis of Local Thinning Tee Pipe Considering Plastic Strengthening Effect
Authors: Su Wei , Luo Wenhao , Dong Xianshan , Liu Renhuai
Published: October 2020

In this paper, the locally thinned three-way structure under internal pressure is analyzed based on the theory of plastic strengthening effect and limit analysis. A finite element model is presented through ANSYS commercial software to simulate the mechanical properties of orthogonal and oblique three-way structures. This paper systematically analyses how the shape and size of the thinning effect the plastic limit load of the pipe and what is the typical failure mode of plastic failure. Some valuable conclusions are drawn, which provide a useful reference for the design and production of the tee pipe.
Research on Liquid Characteristic Sensing Technology of Quartz Tuning Fork Based on COMSOL Multiphysics
Authors: Ou Chunqian , Ding Jiafeng , Li Xinmei , Xiao Dihong , Zhang Cong
Published: October 2020

In this paper, the relationship between the liquid characteristic parameters and the resonance characteristics of the quartz tuning fork is studied through impedance analysis and computer simulation. Firstly, the three-dimensional model of the quartz tuning fork driven by AC voltage is established using finite element analysis software, and the vibration mode and frequency response of the quartz tuning fork were analyzed. Then, the impedance spectrum of the quartz tuning fork in the air is measured by experiment, and its equivalent circuit parameters are estimated. This result is consistent with the equivalent circuit parameters estimated by simulation, which proves the effectiveness of the simulation. Finally, the values of the geometric parameters A and B are calculated by the frequency response of the quartz tuning fork in the liquid and used for the calculation of the density and viscosity of the liquid with unknown characteristics. The research provides a theoretical basis and experimental support for the design of quartz tuning fork liquid characteristic sensors.
Comprehensive Evaluation and Experimental Research on Power Performance of BEV
Authors: Hu Zongmei , Huang Yangzhi
Published: October 2020

This paper compares the differences between battery electric vehicles (BEV) and fuel vehicles, concludes the blind spots in the dynamic evaluation of BEV, and sets up mathematical models of the power performance of BEV, and builds a subjective evaluation system based on mathematical modeling. Test the objective evaluation data of the benchmark model, and subjectively evaluate the test results. The subjective evaluation test shows that the problem of longer acceleration time in the objective performance test of model 2 is mainly caused by the acceleration and deviation of the car in moving, which can reflect the results of the objective test and reflect the true feelings of the driver. The system can be used as the main basis for the evaluation of new BEV on the market. It is worthy of further promotion and research.
Research on Position Error of External Radiation Radar Sensor Based on 3D Positioning Algorithm
Authors: Duo Liu
Published: October 2020

The paper establishes a measurement-launch station correlation model of a single-frequency off-line radar system, derives the principles of the three-dimensional TOA positioning method and the two-dimensional TOA positioning method to estimate the target height, and gives the analysis of the GDOP positioning accuracy of the corresponding algorithm, and Through the simulation verification of a three-transmission single-receiving external radiation source positioning model, the effects of different algorithms on positioning accuracy and measurement-transmission station correlation are analysed. The results show that using the two-dimensional TOA positioning method to estimate the target height can improve the measurement-transmitting station correlation probability of the single-frequency off-line radiation source radar.
Lattice Vibration and Field Model for Phonons
Authors: Xm Z , Lü Jingjing , Wei Hongliang , Liang Wenhao
Published: October 2020

In this letter, we first briefly review Hamiltonian and Newtonian method for solving lattice vibration. Second, the equivalence between phonons and Klein-Gordon particles is proven. Finally, we use the new method to analyse some simple models and compute their phonon spectrum as well as Berry curvature.
Design and analysis of optical system of semi-active laser seeker
Authors: Pu Xiaoqin , Du Yawen , Dong Quanlin
Published: October 2020

The laser seeker is an important part of navigation guided weapons. The working principle of the laser seeker was expounded, and the optical system of the seeker was designed according to the system index requirements. Its optical system is mainly composed of a receiving optical lens combination and a four-quadrant detector. According to the system performance and technical indicators such as the detection distance of the seeker, the receiving clear aperture, and distortion, the laser imaging spot diameter and the center position range were simulated. The optical system model was established by using CODE-V software. And the spot quality was optimized and evaluated through distortion, trace map, and radial envelope energy curve. Finally, an optical system that satisfies the requirements is designed, and the spot imaging quality is great, and the angular tracking accuracy reaches 0.10° / s.
Design and application of mobile phone anti loss based on electronic information
Authors: Luo Jiachun , Yuan Ming , Chen Shen , Yong Sun , Chen Tianyu
Published: October 2020

With the continuous development of science and technology, artificial intelligence technology has gained a good opportunity. It has brought many conveniences to human production and life, and solved many problems that could not be solved before. How to apply electronic information technology has become the focus of attention. It can quickly solve different difficult problems in each link, improve work efficiency and design accuracy. And in the design process to improve and improve the actual design requirements at the same time to ensure the quality level. This paper designs a mobile phone anti loss device, which is mainly composed of STC89C52 minimum single chip system, Bluetooth module, power supply and anti-loss device. The anti-loss system of mobile phone needs a smart phone supporting Bluetooth to connect with the Bluetooth main board. The data between the single chip computer and Bluetooth is transmitted to the anti-loss device of mobile phone through the serial port. When the Bluetooth of the mobile phone is successfully connected to the Bluetooth motherboard, the anti-loss device shows that it is connected. When the distance between the mobile phone and the Bluetooth main board exceeds the safe distance, disconnect the connection and alarm the mobile phone and the Bluetooth main board at the same time.
A Multi-Parameter Fusion Turning Force Prediction Method Considering the Arc Radius of the Tool Tip
Authors: Gou Jianfeng , Zhang Guangpeng
Published: October 2020

According to the force analysis of turning, the principle of oblique cutting is applied. A new multi-parameter fusion turning force prediction method considering the radius of cutter tip arc is proposed. The mathematical model of new turning force prediction is established. The influence of cutting parameters, cutting parameters and machining conditions on the cutting force is considered in this method. By using the method of cutting force coefficient of the front cutting face, three cutting force coefficients on the front cutting face can be solved by one turning experiment, and the turning force prediction can be realized under the conditions of different cutting tool geometry parameters and different cutting parameters. Finally, the feasibility of the method is verified by TC4 turning test of titanium alloy. And it has high prediction accuracy.