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Complete Solution for Quasicrystals 认领
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作者 Antony J. Bourdillon 《现代物理(英文)》 2020年第4期581-592,共12页
A set of discoveries are described that complete the structural model and diffraction theory for quasicrystals. The irrational diffraction indices critically oppose Bragg diffraction. We analyze them as partly rationa... A set of discoveries are described that complete the structural model and diffraction theory for quasicrystals. The irrational diffraction indices critically oppose Bragg diffraction. We analyze them as partly rational;while the irrational part determines the metric that is necessary for measurement. The measurement is verified by consistency with the measured lattice parameter, now corrected with the metric and index. There is translational symmetry and it is hierarchic, as is demonstrated by phase-contrast, optimum-defocus imaging. In Bragg’s law, orders are integral, periodic and harmonic;we demonstrate harmonic quasi-Bloch waves despite the diffraction in irrational, geometric series. The harmonicity is both local and long range. A breakthrough in understanding came from a modified structure factor that features independence from scattering angle. Diffraction is found to occur at a given “quasi-Bragg condition” that depends on the special metric. This is now analyzed and measured and verified: the metric function is derived from the irrational part of the index in three dimensions. The inverse of the function is exactly equal to the metric that was first discovered independently by means of “quasi-structure factors”. These are consistent with all structural measurements, including diffraction by the quasicrystal, and with the measured lattice parameter. 展开更多
关键词 QUASICRYSTAL ICOSAHEDRA Hierarchic Integral Periodic HARMONIC IRRATIONAL GEOMETRIC Series Metric
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A study on periodic boundary condition in direct numerical simulation for gas–solid flow 认领
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作者 Shiwen Liu Xiaowen Liu +2 位作者 Feiguo Chen Limin Wang Wei Ge 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2020年第1期236-241,共6页
Direct numerical simulation(DNS) of gas–solid flow at high resolution has been carried out by coupling the lattice Boltzmann method(LBM) for gas flow and the discrete element method(DEM) for solid particles. However,... Direct numerical simulation(DNS) of gas–solid flow at high resolution has been carried out by coupling the lattice Boltzmann method(LBM) for gas flow and the discrete element method(DEM) for solid particles. However,the body force periodic boundary condition(FPBC) commonly used to cut down the huge computational cost of such simulation has faced accuracy concerns. In this study, a novel two-region periodic boundary condition(TPBC) is presented to remedy this problem, with the flow driven in the region with body force and freely evolving in the other region. With simulation cases for simple circulating fluidized bed risers, the validity and advantages of TPBC are demonstrated with more reasonable heterogeneity of the particle distribution as compared to the corresponding case with FPBC. 展开更多
关键词 Direct numerical simulation PERIODIC BOUNDARY CONDITION Two-region PERIODIC BOUNDARY CONDITION Gas–solid flow HETEROGENEITY
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Periodic surface functional group density on graphene via laserinduced substrate patterning at Si/SiO2 interface 认领
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作者 Karolina A.Drogowska-Horna Inam Mirza +8 位作者 Alvaro Rodriguez Petr Kovaricek Juraj Sladek Thibault J.-Y.Derrien Mindaugas Gedvilas Gediminas Raciukaitis Otakar Frank Nadezhda M.Bulgakova Martin Kalbac 《纳米研究:英文版》 SCIE EI CAS CSCD 2020年第9期2332-2339,共8页
Controlling the spatial distribution of functional groups on two-dimensional(2D)materials on a micrometer scale and below represents a fascinating opportunity to achieve anisotropic(opto)electronic properties of these... Controlling the spatial distribution of functional groups on two-dimensional(2D)materials on a micrometer scale and below represents a fascinating opportunity to achieve anisotropic(opto)electronic properties of these materials.Periodic patterns of covalent functionalization can lead to pericxJic potentials in the monolayer;however,creating such superstructures is very challenging.Here,we describe an original approach to the periodic functionalization of graphene induced by substrate patterning using a pulsed laser.Laser-induced periodic surface structures(LIPSS)are produced on silicon wafers with thermally-grown oxide layers.The irradiation conditions for the formation of UPSS confined at the Si02/Si interface have been unravelled.LIPSS imprint their periodicity to the reactivity of the monolayer graphene placed on the substrate via modulation of its local doping level.This method is clean,straightforward and scalable with high spatial resolution. 展开更多
关键词 two-dimensional(2D)materials graphene functionalization laser-induced periodic surface structures(LIPSS) periodic patterns Raman spectroscopy atomic force microscopy(AFM)
文章速递基于结构相似性与模板校正的织物瑕疵检测方法 认领
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作者 杨达 狄岚 +1 位作者 赵树志 梁久祯 《智能系统学报》 CSCD 北大核心 2020年第3期475-483,共9页
针对复杂的具有周期性结构的织物瑕疵检测,提出一种基于结构相似性与模板校正的织物瑕疵检测方法。通过图案的周期性,得到图案单位模板大小,再对图像自动分割,同时应用基于模板校正的方法以减少晶格之间未对准的影响,并构建均值模板。... 针对复杂的具有周期性结构的织物瑕疵检测,提出一种基于结构相似性与模板校正的织物瑕疵检测方法。通过图案的周期性,得到图案单位模板大小,再对图像自动分割,同时应用基于模板校正的方法以减少晶格之间未对准的影响,并构建均值模板。通过计算所有晶格间的结构相似性,并将相似关系通过传递闭包的方式得到等价关系,再进行晶格间的聚类。之后通过阈值分割方法,完成瑕疵区域的检测。通过实验表明,改进后的算法检测效果较好,本文算法显著提高了样本的查准率。 展开更多
关键词 结构相似性 周期性 模板校正 单位模板 自动分割 相似关系 阈值分割 瑕疵检测
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文章速递Harmonic balance-based approach for optimal time delay to control unstable periodic orbits of chaotic systems 认领
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作者 Y.M.Chen Q.X.Liu J.K.Liu 《力学学报:英文版》 SCIE EI CAS CSCD 2020年第4期918-925,共8页
As a classical technique for chaos suppression,the time-delayed feedback controlling strategy has been widely developed by stabilizing unstable periodic orbits(UPOs)embedded in chaotic systems.A critical issue for ach... As a classical technique for chaos suppression,the time-delayed feedback controlling strategy has been widely developed by stabilizing unstable periodic orbits(UPOs)embedded in chaotic systems.A critical issue for achieving high controlling precision is to search for an appropriate time delay.This paper proposes a simple yet effective approach,based on incremental harmonic balance method,to determine the optimal time delay in the delayed feedback controller.The time delay is adjusted within the iterative scheme provided by the proposed method,and finally converges to the period of the target UPO.As long as the optimal time delay is fixed,moreover,the attained solution makes it quite convenient to analyze its stability according to the Floquet theory,which further provides the effective interval of the feedback gain. 展开更多
关键词 Chaos control Unstable periodic orbit Delayed feedback Optimal time delay Incremental harmonic balance method
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Numerical Approximation of Stochastic Theta Method for Random Periodic Solution of Stochastic Differential Equations 认领
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作者 Rong WEI Chuan-zhong CHEN 《应用数学学报:英文版》 SCIE CSCD 2020年第3期689-701,共13页
In this paper,we make use of stochastic theta method to study the existence of the numerical approximation of random periodic solution.We prove that the error between the exact random periodic solution and the approxi... In this paper,we make use of stochastic theta method to study the existence of the numerical approximation of random periodic solution.We prove that the error between the exact random periodic solution and the approximated one is at the 1/4 order time step in mean sense when the initial time tends to∞. 展开更多
关键词 Stochastic theta method random periodic solution numerical approximation
Nonlinear dynamical magnetosonic wave interactions and collisions in magnetized plasma 认领
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作者 M.ISHAQ Hang XU 《应用数学和力学:英文版》 SCIE EI CSCD 2020年第8期1139-1156,共18页
The one-dimensional nonlinear dynamical wave interactions in a system of quasineutral two-fluid plasma in a constant magnetic field are investigated.The existence of the travelling wave solutions is discussed.The modu... The one-dimensional nonlinear dynamical wave interactions in a system of quasineutral two-fluid plasma in a constant magnetic field are investigated.The existence of the travelling wave solutions is discussed.The modulation stability of linear waves and the modulation instability of weakly nonlinear waves are presented.Both suggest that the Korteweg-de Vries(KdV)system is modulationally stable.Besides,the wave interactions including the periodic wave interaction and the solitary wave interaction are captured and presented.It is shown that these interacting waves alternately exchange their energy during propagation.The Fourier spectrum analysis is used to depict the energy transformation between the primary and harmonic waves.It is known that the wave interactions in magnetized plasma play an important role in various processes of heating and energy transportation in space and astrophysical plasma.However,few researchers have considered such magnetohydrodynamic(MHD)wave interactions in plasma.It is expected that this work can provide additional insight into understanding of behaviors of MHD wave interactions. 展开更多
关键词 magnetosonic wave periodic wave solitary wave modulation instability Fourier spectrum dispersion relation
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台风影响下海水养殖塘水环境响应特征分析 认领
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作者 杨栋 丁烨毅 +2 位作者 黄鹤楼 朱佳敏 申子彬 《中国农学通报》 2020年第1期82-88,共7页
挑选2013—2017年对宁波影响较大的强降水型和非强降水型台风,基于台风影响期间宁波地区5个代表性海水养殖塘水环境因子观测资料(水温T、溶解氧DO、盐度S、酸碱度pH),通过谐波分析和数理统计,以期探究台风期间海水养殖塘水环境因子的变... 挑选2013—2017年对宁波影响较大的强降水型和非强降水型台风,基于台风影响期间宁波地区5个代表性海水养殖塘水环境因子观测资料(水温T、溶解氧DO、盐度S、酸碱度pH),通过谐波分析和数理统计,以期探究台风期间海水养殖塘水环境因子的变化特征及关键影响因子。结果显示:(1)2阶谐波能反映养殖塘水体的T、pH和DO变化,3阶谐波能较好模拟S变化;(2)在台风影响关键期,水环境因子的谐波构成中短周期谐波的比重整体上升,强降水型台风短周期谐波的比重较非强降水台风高;(3)在相关性分析基础上,利用水环境和气象要素谐波构成及变化对比,可得T和DO变化主要受气温影响,强降水对S和pH影响显著。谐波方法能较好地模拟台风影响期间海水养殖塘水环境因子的变化特征,并为养殖塘水环境关键气象影响因子筛选提供新的思路。 展开更多
关键词 台风 养殖塘水环境 周期性 影响因子 谐波
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Sleep architecture, periodic breathing and mood disturbance of expeditioners at Kunlun Station(4087 m) in Antarctica 认领
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作者 XU Chengli LIU Shiying +1 位作者 KONG Zhanping CHEN Nan 《极地科学进展:英文版》 CSCD 2020年第3期215-223,共9页
Several studies have reported the detrimental impacts of hypoxia exposure on sleep.Chinese Kunlun Station(altitude 4087 m)is located at Dome A,the highest point on the Antarctic ice sheet and one of the most extreme e... Several studies have reported the detrimental impacts of hypoxia exposure on sleep.Chinese Kunlun Station(altitude 4087 m)is located at Dome A,the highest point on the Antarctic ice sheet and one of the most extreme environments on Earth.This study investigated alteration of sleep,breathing and mood status in healthy expeditioners at Kunlun Station at Dome A.The study examined 10 male volunteers of the inland transverse party to Kunlun Station during the 31st Chinese National Antarctic Research Expedition,and valid data from eight volunteers were analyzed.Sleep structure,breathing pattern and mood were monitored using portable polysomnography(PSG)and profile of mood state(POMS)at two time points:(1)at Zhongshan Station(10 m)before departure to Kunlun Station;(2)on nights 12–13 of residence at Kunlun Station.Slow-wave sleep(Stage 3 non-rapid eye movement)was markedly reduced at Kunlun Station(P<0.01).Total sleep time,sleep efficiency and sleep latency showed no significant changes.Total respiratory events(P<0.05),apnea/hypopnea index(AHI)(P<0.05)and hypopnea index(P<0.01)substantially increased at Kunlun Station.The most common respiratory disorder was periodic breathing,occurring almost exclusively during non-rapid eye movement sleep.The oxygen desaturation index increased markedly(P<0.05),while nocturnal oxygen saturation dramatically fell at Kunlun Station(P<0.05).Vigor scores decreased at Kunlun Station(P<0.05).Expeditioners exhibited reduced slow wave sleep,induced periodic breathing,decreased oxygen saturation and decreased vigor at Kunlun Station. 展开更多
关键词 SLEEP periodic breathing expeditioner Kunlun Station ANTARCTICA
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Time-headway distribution for random-sequential-update TASEP with periodic and open boundaries 认领
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作者 Pavel Hrabák 《交通运输工程学报(英文版)》 CSCD 2020年第1期30-41,共12页
The temporal-headway distribution for Totally Asymmetric Simple Exclusion Process(TASEP) with random-sequential update is investigated.Considering the stationary/steady state of the process,exact formula for the step-... The temporal-headway distribution for Totally Asymmetric Simple Exclusion Process(TASEP) with random-sequential update is investigated.Considering the stationary/steady state of the process,exact formula for the step-headway distribution is derived for conditions when the stationary measure is Bernoulli,Le.,for periodic boundaries and for open boundaries with entering boundary rate α and leaving boundary rate 0 satisfying α+β=1.The step-headway formula for general values of boundary rates is calculated numerically by means of the matrix product ansatz.The formula is applicable mainly for the model defined on finite small lattice representing short segment of complex network.In this case the dependency of the motion of individual particles is noticeable and cannot be neglected.The finite lattice results are compared to continuous time distribution obtained by mans of the large L limit It can be observed that the scaled distribution converges quite fast to continuous time distribution.However,in the case of rather small lattice the distribution significantly differs from the limiting one.Moreover,in the case of Bernoulli stationary measure,the distribution is not dependent on the position of the reference site on the lattice.Considering general values of boundary parameters,the shape of the distribution is influenced by the density profile of the process near boundaries.This influence vanishes with increasing lattice size. 展开更多
关键词 Transportation TASEP Time-headway DISTRIBUTION Random-sequential UPDATE PERIODIC and open boundaries
Observations of TEC Depletion,Periodic Structure of TEC,ROTI and Scintillation Associated with ESF Irregularities over South China 认领
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作者 DENG Kun MA Yonghui +2 位作者 LIU Minbo GUO Zhixiong WANG Shu 《空间科学学报》 CAS CSCD 北大核心 2020年第3期331-340,共10页
The observations of Global Positioning System(GPS) scintillation,Total Electron Content(TEC)depletion,the periodic structure of TEC and Rate of TEC Index(ROTI) over south China were presented.Data were collected from ... The observations of Global Positioning System(GPS) scintillation,Total Electron Content(TEC)depletion,the periodic structure of TEC and Rate of TEC Index(ROTI) over south China were presented.Data were collected from GPS observations at stations of Shenzhen and Guangzhou from 2011 to 2012.This study reported that the ratio of simultaneous occurrences of TEC depletions with strong scintillations was higher than that of TEC depletions with weak scintillations in vernal and autumnal equinoxes of 2011 over South China.The number of the periodic structures of TEC with depletion contained was greater than that with no depletion contained corresponding to strong scintillations.The structure of the slab of plasma irregularities could be responsible for the simultaneous occurrences of TEC depletion with strong scintillations and ROTI.Before and during the occurrences of strong scintillation,there was Large-Scale Wave Structure(LSWS) which provided the seed ionization perturbation to trigger ESF irregularities and contributed to the periodic structure of TEC. 展开更多
关键词 GPS scintillation Total Electron Content(TEC) TEC depletion Periodic structure of TEC Rate of TEC Index(ROTI)
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Free and forced vibration of layered one-dimensional quasicrystal nanoplates with modified couple-stress effect 认领
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作者 JunHong Guo Miao Zhang +1 位作者 WeiQiu Chen XiaoYan Zhang 《中国科学:物理学、力学、天文学英文版》 SCIE EI CAS CSCD 2020年第7期120-121,共2页
To the editor,A new type of solid, called quasicrystal (QC) was discovered after Shechtman et al.[1] accidently got in 1982 a five-fold symmetry diffraction image of rapidly cooled Al-Mn alloys.In contrast with crysta... To the editor,A new type of solid, called quasicrystal (QC) was discovered after Shechtman et al.[1] accidently got in 1982 a five-fold symmetry diffraction image of rapidly cooled Al-Mn alloys.In contrast with crystals with periodic atomic arrangement,QCs have perfect long-range order (like mirror symmetry)but no periodic translational symmetry. Due to their intrinsic brittleness at room temperature, QCs cannot be used directly as structural materials. However, QCs as thin films and coatings of metals in industry are applied to surface modified materials and the reinforcing phase in structural materials. 展开更多
关键词 materials. SYMMETRY periodic
基于AMESim的多执行机构周期性顺序动作建模方法研究 认领
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作者 陈奇 任德新 梁爽 《液压气动与密封》 2020年第8期78-81,共4页
该文提出了一种基于AMESim仿真软件的,对含有多个执行机构的液压系统进行周期性顺序动作控制的建模方法,在AMESim中建立了仿真模型并进行了仿真分析,得出了多个执行机构周期性顺序动作的位移曲线,验证了该方法的正确性。该方法对于有周... 该文提出了一种基于AMESim仿真软件的,对含有多个执行机构的液压系统进行周期性顺序动作控制的建模方法,在AMESim中建立了仿真模型并进行了仿真分析,得出了多个执行机构周期性顺序动作的位移曲线,验证了该方法的正确性。该方法对于有周期性动作控制要求的液压系统建模仿真具有借鉴和指导意义。 展开更多
关键词 AMESIM 多执行机构 周期性 建模
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Banana Xanthomonas wilt dynamics with mixed cultivars in a periodic environment Juliet 认领
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作者 N.Nakakawa Joseph Y.T.Mugisha +1 位作者 Michael W.Shaw Eldad Karamura 《生物数学学报:英文版》 SCIE 2020年第1期141-162,共22页
In this paper,we study a deterministic model with non-autonomous system for mixed cultivars to assess the effect of cultivar susceptibility and seasonal variation on banana Xanthomonas wilt(BXW)disease dynamics.A spec... In this paper,we study a deterministic model with non-autonomous system for mixed cultivars to assess the effect of cultivar susceptibility and seasonal variation on banana Xanthomonas wilt(BXW)disease dynamics.A special case of two cultivars classified as highly susceptible for inflorescence infection(ABB)and less susceptible(AAA)cultivar is considered.The basic reproduction number corresponding to the non-autonomous sys­tem is derived and numerically computed to determine disease dynamics.Results showed that the disease dies out whenever the periodic basic reproduction number is less than unity and a periodic solution is obtained when it is greater than one.Results further showed that for both cultivars,the basic reproduction number increases with increas­ing values of the transmission rates and declines exponentially with increasing values of roguing rates.The critical roguing rate of ABB-genome cultivar was higher than that of AAA-genome cultivars.The peaks in disease prevalence indicate the importance of effective implementation of controls during the rainy season.We conclude that highly susceptible cultivars play an important role in the spread of BXW and control measures should be effectively implemented during the rainy season if BXW is to be eradicated. 展开更多
关键词 Banana Xanthomonas wilt non-autonomous system CULTIVARS periodic basic reproduction number.
Boundedness and Almost Periodicity of Solutions for a Class of Semilinear Parabolic Equations with Boundary Degeneracy 认领
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作者 Yi XIE Peidong LEI 《数学年刊:B辑英文版》 SCIE CSCD 2020年第2期303-324,共22页
In this paper the authors investigate the boundedness and almost periodicity of solutions of semilinear parabolic equations with boundary degeneracy. The equations may be weakly degenerate or strongly degenerate on th... In this paper the authors investigate the boundedness and almost periodicity of solutions of semilinear parabolic equations with boundary degeneracy. The equations may be weakly degenerate or strongly degenerate on the lateral boundary. The authors prove the existence, uniqueness and global exponential stability of bounded entire solutions, and also establish the existence theorem of almost periodic solutions if the data are almost periodic. 展开更多
关键词 ALMOST periodic SOLUTION BOUNDED entire SOLUTION BOUNDARY DEGENERACY
冗余I/O模块切换方法的设计与实现 认领
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作者 臧峰 徐卫峰 +1 位作者 吴波 牛洪海 《自动化仪表》 CAS 2020年第8期57-60,共4页
在工业过程控制领域,为了提高系统的可靠性与稳定性,一般都进行冗余设计。因此,设计了一种动态可配置的冗余I/O模块系统,包括控制器、I/O底座、I/O模块和通信总线。其中,冗余通信总线集成在I/O底座中,I/O模块可通过热插拔插入I/O底座。... 在工业过程控制领域,为了提高系统的可靠性与稳定性,一般都进行冗余设计。因此,设计了一种动态可配置的冗余I/O模块系统,包括控制器、I/O底座、I/O模块和通信总线。其中,冗余通信总线集成在I/O底座中,I/O模块可通过热插拔插入I/O底座。控制器对I/O模块进行配置,可设置成单模块运行或冗余模块运行,并把设置模式下发给I/O模块。I/O模块初始化为“初始化”运行方式。当接收到控制器下发的是冗余运行方式时,I/O模块进行状态决策,决策出主I/O模块和备I/O模块,并把决策结果反馈给控制器。备I/O模块周期性地监视主I/O模块状态,当发现主I/O模块丢失或故障等级高于本身时,则发送命令给对方,让其切换为备I/O模块,当前备I/O模块主动升级为主I/O模块。该方法通过高速通信的方式,实现了主备I/O模块的决策。 展开更多
关键词 冗余 控制器 I/O模块 热插拔 可配置 状态决策 周期性
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An Interdisciplinary Perspective from the Earth Scientist's Periodic Table:Similarity and Connection between Geochemistry and Metallurgy 认领
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作者 Fenglong Sun Zhongwei Zhao 《工程(英文)》 SCIE EI 2020年第6期707-715,共9页
In 2003,Railsback proposed the Earth Scientist's Periodic Table,which displays a great deal of elemental geology information in accordance with the natural environment of the earth.As an applied science,metallurgy... In 2003,Railsback proposed the Earth Scientist's Periodic Table,which displays a great deal of elemental geology information in accordance with the natural environment of the earth.As an applied science,metallurgy is based on mineral composition and element behavior,that is similar to geochemistry.In this paper,connections and similarities between geology and metallurgy are identified,based on geochemical laws and numerous metallurgical cases.An obvious connection is that simple cations w让h high and low ionic potential are commonly extracted by hydrometallurgy,while those with intermediate ionic potential are extracted by pyrometallurgy.In addition,element affinity in geology is associated with element migration in metallurgic phases.To be specific,in pyrometallurgy,lithophile elements tend to gather in slags,chalcophile elements prefer the matte phase,siderophile elements are easily absorbed into metal melt,and atmophile elements readily enter the gas phase.Furthermore,in hydrometallurgy,the principles of hard/soft acids and bases(HSABs)offer an explanation of how precipitation and dissolution occur in different solutions,especially for fluoride and chloride.This article provides many metallurgical examples based on the principles of geochemistry to verify these similarities and conn ections. 展开更多
关键词 METALLURGY GEOCHEMISTRY Periodic table Ionic potential Elemental affinity
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Formation of mono-dispersed droplets with electric periodic dripping regime in electrohydrodynamic(EHD) atomization 认领
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作者 Zhentao Wang Qisi Wang +2 位作者 Yaosheng Zhang Yimin Jiang Lei Xia 《中国化学工程学报:英文版》 SCIE EI CAS CSCD 2020年第5期1241-1249,共9页
The formation of controllable size and dripping frequency in electrohydrodynamic(EHD)atomization with electric periodic dripping regime are of much interest and importance because of significant and wide applications,... The formation of controllable size and dripping frequency in electrohydrodynamic(EHD)atomization with electric periodic dripping regime are of much interest and importance because of significant and wide applications,such as micro-encapsulation and ink-printing.In the present study,the experimental and theoretical works were carried out to explore droplet formation in periodic dripping regime in presence of an electric field.The dimensionless electric charge carried by each droplet produced is smaller than the 50%of critical value of the Rayleigh limit,where charge-to-mass ratio of droplets was obtained through the deflection distance in the presence of an electric field.The droplet in electric periodic dripping regime usually undergoes oscillating deformation,and finally forms a spherical droplet below the tip no more than ten times out diameter of tube.The droplet size tens of microns to one hundreds of microns decreases with an increase in applied potential.In the electric dripping mode,droplets size is independent of flow rate and affected by flow rate due to adsorption of surface active species in micro-dripping.The simplified model to predict droplets size was derived from the balance of electric,surface tension and gravity forces.The droplets size calculated in good agreement with the experiments.Meanwhile,the dripping frequency of droplets with rang of a few to several hundred hertz obtained from timeresolved images is highly dependent of liquid flow rate and electric potential.The largest dripping frequency was predicted and in reasonable agreement with the experimental results.In electric periodic dripping regime drop-on-demand droplets in size and dripping frequency further our understanding on the formation of identical droplets and are beneficial to many practical applications. 展开更多
关键词 Electric field Electric periodic dripping Formation Diameter Dripping frequency
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Periodic Solutions for a Damped Rayleigh Beam Model with Time Delay 认领
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作者 Bochao Chen Yong Li 《数学研究通讯:英文版》 CSCD 2020年第3期296-319,共24页
Vibrations of a beam can be described as an Euler-Bernoulli beam,or as a Rayleigh beam or as a Timoshenko beam.In this paper,we establish the existence of periodic solutions in time for a damped Rayleigh beam model wi... Vibrations of a beam can be described as an Euler-Bernoulli beam,or as a Rayleigh beam or as a Timoshenko beam.In this paper,we establish the existence of periodic solutions in time for a damped Rayleigh beam model with time delay,which is treated as a bifurcation parameter.The main proof is based on a Lyapunov-Schmidt reduction together with the classical implicit function theorem.Moreover,we give a sufficient condition for a direction of bifurcation. 展开更多
关键词 Beam equations DAMPING time delay periodic solutions
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Non-spherical aluminum nanoparticles fabricated using picosecond laser ablation 认领
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作者 A.Brahma Swamulu S.Venugopal Rao G.Krishna Podagatlapalli 《矿物冶金与材料学报:英文版》 SCIE EI CAS CSCD 2020年第7期980-986,共7页
We report the picosecond laser ablation of aluminum targets immersed in a polar organic liquid(chloroform,CHCl3)with~2 ps laser pulses at an input energy of~350μJ.The synthesized aluminum nanoparticles exhibited a su... We report the picosecond laser ablation of aluminum targets immersed in a polar organic liquid(chloroform,CHCl3)with~2 ps laser pulses at an input energy of~350μJ.The synthesized aluminum nanoparticles exhibited a surface plasmon resonance peak at~340 nm.Scanning electron microscopy images of Al nanoparticles demonstrated the spherical morphology with an average size of(27±3.6)nm.The formation of smaller spherical Al nanoparticles and the diminished growth could be from the formation of electric double layers on the Al nanoparticles.In addition to spherical aluminum nanoparticles,triangular/pentagonal/hexagonal nanoparticles were also observed in the colloidal solution.Field emission scanning electron microscopy images of ablated Al targets demonstrated laser induced periodic surface structures(LIPSSs),which were the high spatial frequency LIPSSs(HSF-LIPSSs)since their grating period was~280 nm.Additionally,coarse structures with a period of~700 nm were observed. 展开更多
关键词 ablation PICOSECOND SILVER POLAR periodic surfaces electric double layers
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