Effect of varying normal stress on stability and dynamic motion of a spring-slider system with rate- and state-dependent friction

Incorporating rate and state friction laws, stability of linearly stable （i.e., with stiffness greater than the critical value） spring-slider systems subjected to triggering perturbations was analyzed under variable normal stress condition, and comparison was made between our results and that of fixed normal stress cases revealed in previous studies. For systems associated with the slip law, the critical mag- nitude of rate steps for triggering unstable slips are found to have a similar pattern to the fixed normal stress case, and the critical velocity steps scale with a/（b - a） when k = kcr for both cases. The rate-step boundaries for the variable normal stress cases are revealed to be lower than the fixed normal stress case by 7 %-16 % for a relatively large ct = 0.56 with （b - a）/a ranging from 0.25 to 1, indicating easier triggering under the variable normal stress condition with rate steps. The difference between fixed and variable normal stress cases decreases when the α value is smaller. In the same slip- law-type systems, critical displacements to trigger instability are revealed to be little affected by the variable normal stress condition. When k 〉 kcr（V,）, a spring-slider system with the slowness law is much more stable than with the slip law,suggesting that the slowness law fits experimental data better when a single state variable is adopted. In stick-slip motions, the variable normal stress case has larger stress drops than the constant normal stress case. The variable normal stress has little effect on the range of slip velocity in systems associated with the slowness law, whereas systems associated with the slip law have a slowest slip velocity immensely smaller than the fixed normal stress case, by ~ 10 orders of magnitude.

Solid-state synthesis of Sr-and Co-doped LaMnO_3 perovskites

The synthesis process for La 1- x Sr x Mn 1- y Co y O 3- δ ( x = 0.2, 0.3; y = 0.2, 0.8, designated as LSMC below) perovskite oxides prepared by solid state reaction was investigated using DSC/TG, XRD, EPMA and particle size analysis methods. It was found that LSMCs were all of single phase and the synthesis process might be divided into three stages: the decomposition of reactants, the formation of LaMn(Co)O 3 based oxides, and the formation of LSMC solid solution. Typical average and the peak value of particle size, and the specific surface area are 14.65?μm, 16.4?μm and 1.38?m 2/mL, respectively, for mixed reactants and are 23.81?μm, 32.11?μm and 0.5?m 2/mL, respectively, for powder synthesized at 1?200?℃ for 8?h in air.

Modeling of Solid-state Polycondensation of Poly (ethylene terephthalate)

A mathematical model has been developed to handle the reactions in Poly(ethylene terephthalate) (PET) undergoing polycondensation reactions in the solid state. The effect of temperature on chain mobility was considered to estimate the rate constants of chemical reactions. The polymer crystalline fraction is modeled as containing only repeat units, thus concentrating end groups and conden-sates in the amorphous fraction. This model is compared with PET reaction data with good results.

Equation of State of Nuclear Matter in Chiral σ-ω Model

The equation of state of nuclear matter is studied in the 1-loop approximation of chiral linear σ-ω model.By introducing the density-dependent coupling constants, the problem of tachyon pole in the chiral σ-ω model is resolved.The 1-loop contributions ofσ and π mesons to the nucleon's binding energy are included, while the empirical properties of nuclear matter such as saturation density, binding energy, and incompressibility are well reproduced.

Materials Design on the Origin of Gap States in a High-κ/GaAs Interface

Given the demand for constantly scaling micro- electronic devices to ever smaller dimensions, a SiO2 gate dielectric was substituted with a higher dielectric-constant material, Hf（Zr）O2, in order to minimize current leakage through dielectric thin film. However, upon interfacing with high dielectric constant （high-κ） dielectrics, the electron mobility in the conventional Si channel degrades due to Coulomb scattering, surface-roughness scattering, remotephonon scattering, and dielectric-charge trapping.Ⅲ-Ⅴ and Ge are two promising candidates with superior mobility over Si. Nevertheless, Hf（Zr）O2/Ⅲ-Ⅴ（Ge） has much more complicated interface bonding than Si-based interfaces. Successful fabrication of a high-quality device critically depends on understanding and engineering the bonding configurations at Hf（Zr）O2/Ⅲ-Ⅴ（Ge） interfaces for the optimal design of device interfaces. Thus, an accurate atomic insight into the interface bonding and mechanism of interface gap states formation becomes essential. Here, we utilize first- principle calculations to investigate the interface between HfO2 and GaAs. Our study shows that As--As dimer bonding, Ga partial oxidation （between 3＋ and 1＋） and Ga- dangling bonds constitute the major contributions to gap states. These findings provide insightful guidance for optimum interface passivation.

The “Non-Locality” of Entangled States Is Seeming Phenomenon

EPR raised fundamental problems of non-locality (NL) in the case of entangled states (ES) 82 years ago. These problems were not solved until now. EPR and their followers used and would continue to use calculation methods that were available at that time. However, we can easily explain this observable NL as a trivial result of conservation laws (CL) within modern quantum mechanics (MQM). But application of CL requires materialistic descriptions of reality in a micro world in contrast to so-called quantum measurement theory (QMT), which was created mainly in the times of EPR and is widely accepted until now. We have to use a materialistic description, just as many physicists who actually work with high precision do by default. In this article, practical examples are given for real, precise measurements of wave functions of molecules and crystals, which, of course, were not known to EPR and were not noticed by their followers. We should acknowledge that QMT is merely an unneeded complication of simple relations of MQM. NL is the seeming result of these complications.

Tectonic Related Lithium Deposits Another Major Region Found North East Tanzania—A New Area with Close Association to the Dominant Areas: The Fourth of Four

The current “mega” interest in Lithium resources was spurred by the development of Lithium-Ion batteries to aid in restructuring the world’s reliance on carbon spewing power petroleum reserves. Current resources of lithium recovery have fallen into two main categories—Pegmatite, found worldwide associated with felsic intrusions and Brine Related, and now with development in the Southwest United States of America (SWUS), a third category— Tertiary Volcanic clays, are specifically associated with Tertiary volcanics and major Tectonic Plate interactions. “Active” Plate tectonics is important as both the SWUS, the Lithium Triangle of South America (LTSA) and the Tibetan Plateau of China (TPC) producing tertiary (Miocene) volcanism that is important to the development of Lithium resources. The Tanzanian part of the East Africa Rift System (EARS) has features of both the SWUS, tertiary volcanic related “playas” and Continental rifting, the LTSA, tertiary volcanic related “Brines” and a major Tectonic plate event (subduction of an Oceanic Plate beneath the Continental South American Plate) and the TPC, tertiary volcanics (?) and major tectonic plate event (subduction of the Indian Continental Plate under the Eurasian Continental Plate). As well as the association of peralkaline and metaluminous felsic volcanics with Lithium playas of the SWUS and the EARS (Tanzania) “playas”. These similarities led to an analysis of a volcanic rock in Northeast Tanzania. When it returned 1.76% Lithium, a one-kilometer spaced soil sampling program returned, in consecutive samples over 0.20% Lithium (several samples over 1.0% lithium and a high of 2.24% lithium). It is proposed that these four regions with very similar past and present geologic characteristics, occur nowhere else in the world. That three of them have produced Lithium operations and two of them have identified resources of Lithium clay and “highly” anomalous Lithium clays should be regarded as more than “coincidental”.

State of Country Report——Foreign Trade 2009-2010

Facing economic crisis in the world 2009, international market demands suffered a serious recession, also China's foreign trade has encountered unprecedented difficulties. In front of this, Chinese Government takes series of adjustment timely to get over this rough time. So how is China's foreign trade in 2009, and where it will go in 2010, let's have a look at this…

基于ε-支配的多目标进化算法及自适应ε调整策略

提出了一类新的基于ε-支配关系的多目标进化算法.该算法采用配对比较选择和稳态替换策略,提高了算法的收敛速度,降低了计算时间.首先,在保持种群分布性上,采用了一种新的基于ε-支配关系的精英保留策略,避免了传统修剪策略所引起的Pareto前沿面的退化.其次,根据不同ε取值分析了算法收敛性,提出了一种自适应ε调整策略.最后,通过5个常用的双目标测试函数的计算,验证了包括该自适应调整策略的多目标进化算法在求解质量上显著强于NSGAII,SPEA2和ε-MOEA等主流多目标进化算法.

技术创新抑或资本扩张-不同发展战略下的国有上市公司经营绩效比较

文章首先利用聚类分析将国有制造业企业划分为两类,一类是盈利和发展能力较强但资产负债率较低的企业,另一类企业的资产负债率较高但盈利和发展能力较弱。其次,利用我国2010年之后经济增速减缓的实际数据,对这两类企业进行伺服原理中的主导因素检验,发现第一类企业的主导因素是技术创新,第二类的主导因素是资本扩张。由此表明,技术创新为主导的企业具有较强的适应性和竞争力,而资本扩张为主导的企业适应性较弱,在经济增长减速时却往往陷入高负债和低盈利水平状态。因此,解决当前我国国有企业竞争力不强的关键在于国有企业的战略选择,我国政府只有积极引导和激励国有企业将技术创新作为首要的战略发展目标,才能切实提高我国国有企业的竞争力。

S-粗集与它的F-记忆

利用F-记忆S-粗集与它的F-记忆特性,F-记忆S粗集与它的F-记忆特性,给出(f,f)知识,F-记忆S-粗集的概念,利用这些概念,提出F记忆的F记忆显性定理,F-记忆的F记忆显性定理,F-记忆的不变性定理,F记忆可分辨定理,系统状态稳定的记忆识别准则,并给出应用实例.指出了(f,f)记忆知识与系统状态稳定识别之间存在着必然的联系.

非优势 大脑半球缺血性脑卒中患者存在的急性期脑功能连接改 变:基于rs-fMRI技术

目的运用静息态脑功能成像探究非优势大脑半球缺血性脑卒中患者在急性期的脑功能连接的变化。方法以15例健康受试者作为正常对照组,15例非优势大脑半球(右半球)中动脉急性梗塞(发病<72 h)的患者作为卒中组,采用西门子3.0 T超导MRI采集两组患者相关数据,以功能连接为结局指标,并基于Matlab 2012a平台使用DPABI工具包对两组数据进行预处理和统计学分析。结果最终10例患者纳入试验,与健康受试者对比,差异有统计学意义(P<0.005)的感兴趣区(ROI)有11个。以右背外侧额上回为ROI,与左后扣带回(T=6.5173)等脑区功能连接增强;以右眶部额上回为ROI,与左BA18(T=6.0674)等脑区功能连接增强;以左中央沟盖为ROI,与左距状裂周围皮层(T=5.7831)等脑区功能连接增强;以右眶内额上回为ROI,与左梭状回(T=5.7361)等脑区功能连接增强;以左岛叶为ROI,与左梭状回(T=4.5436)等脑区功能连接增强;以右岛叶为ROI,与右小脑后叶(T=4.9352)等脑区功能连接增强;以左楔叶为ROI,与左岛叶(T=5.6924)等脑区功能连接增强;与右梭状回为ROI,与左眶回(T=8.4505)等脑区功能连接增强;以左楔前叶为ROI,与左豆状壳核(T=5.1894)等脑区功能连接增强;以左中央旁小叶为ROI,与左豆状壳核(T=7.9109)等脑区功能连接增强;以左颞横回为ROI,与左舌回(T=5.9146)等脑区功能连接增强。结论非优势大脑半球缺血性脑卒中患者在急性期存在与视觉、听觉、高级认知及运动相关的脑区之间功能连接增强的脑功能变化。

The New Trend:US’Strengthening Dominance in Cyberspace

With its advantages in technological innovation,industrial leadership,and international influence,the United States(US)has long dominated cyberspace.However,with the evolution of international power structures,competition for power in cyberspace has intensified,thereby bringing unprecedented challenges to the US’dominance.Cyberspace has become an increasingly important battleground,especially in the context of Sino-US strategic competition.To maintain its advantages and safeguard national interests,the US government has made continuous efforts to explore and consolidate cyberspace power from three dimensions—adjusting ideologies,strengthening capabilities,and seeking institutional power.These trends will have profound impacts on the future development of,and power structures in,cyberspace.

Elaborately tuning the electronic structure of single-atom nickel sites using nickel nanoparticles to markedly enhance the electrochemical reduction of nitrate into ammonia

The electrochemical reduction of nitrate to ammonia(NH3) can be used to recycle nitrogen and offers a decarbonized route for sustainable NH3production,but requires efficient electrocatalysts.Herein,we have rationally designed and fabricated a novel self-supported electrocatalyst comprised of Ni nanoparticles(NiNPs) embedded in Ni single atoms(NiSAs) anchored to nitrogen-doped carbon nanotubes grown on carbon cloth(NiNPs@NiSAs-NCNTs/CC) used for an efficient nitrate reduction reaction(NO3-RR) to produce NH_(3).The electrocatalyst can attain a maximum NH3yield rate of 27.67±1.16 mgNH3h^(-1)cm^(-2)at-1.4 V vs.reversible hydrogen electrode(RHE) and nearly 100% Faradic efficiency in the range of-1.2--1.4 V vs.RHE in a neutral medium,outperforming the previously reported Ni-based catalysts.Our experimental analysis and theoretical calculations have demonstrated that the moderate electrondeficient state of NiSAsregulated by NiNPsnot only facilitates the enrichment of NO_(3)^(-),but also benefits the formation of NO3*and decrease in the energy barrier of the rate-limiting step,thus resulting in the enhanced NO3-RR performance.

A New Cadmium(Ⅱ) Coordination Polymer Extended through Hydrogen Bonds and π-π Stacking Interactions: Synthesis and Photoluminescence Property

A new coordination polymer, {[Cd(OPY)(tdc)(HO)]·H2 O}n(OPY = 4,4?-(oxybis(4,1-phenylene))dipyridine, H2 tdc = thiophene-2,5-dicarboxylic acid), has been synthesized hydrothermally based on a V-shaped ligand OPY. The structure was fully characterized by elemental analysis, FT-IR spectroscopy, and X-ray single-crystal diffraction analysis. In1, two OPY ligands and one water molecule acted as terminal ligands coordinating to Cdcation to form [Cd(OPY)HO]units, which are then linked by tdc2-ligands to generate a one-dimensional chain. Every two adjacent chains linked by extensive O–H···O hydrogen bonds constitute one-dimensional double-chains, and such chains are extended into two-dimensional layers via O–H···N hydrogen bonds. These layers are further connected to form a three-dimensional supramolecular architecture via π-π stacking interactions. In addition, the thermal stability and solid state fluorescence property of 1 were also investigated.

Verifying the accuracy of interlocking tables for railway signalling systems using abstract state machines

Railway transportation system is a critical sector where design methods and techniques are defined by international standards in order to reduce possible risks to an acceptable minimum level. CENELEC 50128 strongly recommends the utilization of finite state machines during system modelling stage and formal proof methods during the verifi- cation and testing stages of control algorithms. Due to the high importance of interlocking table at the design state of a sig- nalization system, the modelling and verification of inter- locking tables are examined in this work. For this purpose, abstract state machines are used as a modelling tool. The developed models have been performed in a generalized structure such that the model control can be done automatically for the interlocking systems. In this study, NuSMV is used at the verification state. Also, the consistency of the developed models has been supervised through fault injection. The developed models and software components are applied on a real railway station operated by Metro Istanbul Co.

Theoretical Study of the Molecular and Electronic Structures of CPDT-TCNQ and Its Difluoro and Dimethyl Derivatives

CPDT-TCNQ and its derivatives are good candidates for charge-transfer acceptors. In this work, the electronic ground and excited states of CPDT-TCNQ as well as its difluoro and dimethyl derivatives are studied. The ground state optimized structures and energies were obtained using a restricted （closed-shell） density functional theory （DFT） as approximated by the various hybrid functionals （RB3LYP, RB3P86, RB3PW91）. The 6-31G＊＊ and 6-31＋G＊＊ basis sets were employed in calculations. All derivatives are planar and exhibit a quinoid structure in their electronic ground states. The energy and oscillator strength of the first 15 singlet-singlet electronic transitions have been investigated by applying the dine-dependent density functional theory （TD-DFT） approximations to the correspondingly optimized ground state geometries. The results show the strongest absorption in electronic spectra of molecules due to the HOMO-LUMO electronic transition of the thiophene backbone.

Fuzzy Modeling on L - R Fuzzy Number and Its Application

A new fuzzy modeling method, which based on L - R fuzzy number, is discussed in this paper. First, the fuzzy state equation model is constructed based on fuzzy state variable,fuzzy Input variable and fuzzy output variable whkh are represented by L - R fuzzy number. And then, identification of time - varying parameter in this model is discussed further. At the end, a simulated application is given to Indicate the effectiveness of this fuzzy modeling method.

First-principles study of the co-effect of carbon doping and oxygen vacancies in ZnO photocatalyst

Although tuning band structure of optoelectronic semiconductor-based materials by means of doping single defect is an important approach for potential photocatalysis application,C-doping or oxygen vacancy(Vo)as a single defect in ZnO still has limitations for photocatalytic activity.Meanwhile,the influence of co-existence of various defects in ZnO still lacks sufficient studies.Therefore,we investigate the photocatalytic properties of ZnOx C0.0625(x=0.9375,0.875,0.8125),confirming that the co-effect of various defects has a greater enhancement for photocatalytic activity driven by visible-light than the single defect in ZnO.To clarify the underlying mechanism of co-existence of various defects in ZnO,we perform systematically the electronic properties calculations using density functional theory.It is found that the coeffect of C-doping and Vo in ZnO can achieve a more controllable band gap than doping solely in ZnO.Moreover,the impact of the effective masses of ZnO_(x)C_(0.0625)(x=0.9375,0.875,0.8125)is also taken into account.In comparison with heavy Vo concentrations,the light Vo concentration(x=0.875)as the optimal component together with C-doping in ZnO,can significantly improve the visible-light absorption and benefit photocatalytic activity.

O(t^(-β))-SYNCHRONIZATION AND ASYMPTOTIC SYNCHRONIZATION OF DELAYED FRACTIONAL ORDER NEURAL NETWORKS

This article explores the O(t^(-β))synchronization and asymptotic synchronization for fractional order BAM neural networks(FBAMNNs)with discrete delays,distributed delays and non-identical perturbations.By designing a state feedback control law and a new kind of fractional order Lyapunov functional,a new set of algebraic sufficient conditions are derived to guarantee the O(t^(-β))Synchronization and asymptotic synchronization of the considered FBAMNNs model;this can easily be evaluated without using a MATLAB LMI control toolbox.Finally,two numerical examples,along with the simulation results,illustrate the correctness and viability of the exhibited synchronization results.