Devitrification process in rapidly solidified Al-Ni-Cu-Nd metallic glass

In the present study, rapidly solidified ribbons of Al87 Ni7Cu3 Nd3 metallic glass was prepared by usingmelt spinning. Devitrification process of the totally amorphous ribbons was investigated by high temperature X-raydiffraction analysis, combining with differential scanning calorimetry, under continuous and isothermal heating re-gime. The X-ray diffraction intensity and full width at the half maximum (FWHM) were analyzed to investigate theincrease of crystallized amount and growth of α-Al crystal particles. The results show that under continuous heatingregime, the metallic glass devitrifies via two main stages: primary crystallization, resulting in two-phase mixture ofα-Al plus residual amorphous phase, and secondary crystallization, corresponding to rapid precipitation of some in-ter-metallic phases in the form of dispersion or eutectic mixture. Under isothermal heating regime, only Al crystalprecipitates from the Al-rich amorphous matrix at low temperature, and when heating at 280 ℃ only Al crystal pre-cipitates within a short time, and then Al8 Cu4 Nd forms, followed by Al3 Ni, in the residual amorphous phase. Whenheating at higher temperature or for longer time, Aln Nd3 forms, the amorphous phase disappears, and the ribbonsdevelop into polycrystalline morphologies with multiply phase mixture of a-Al, Al8 Cu4 Nd, Al3 Ni, and Al11 Nd3.

利用交流磁化率无接触测量Bi-2223/Ag高温超导带材的E-J特性

对Bi-2223/Ag超导带材的交流磁化率(χ=χ′+jχ″)随交流磁场的峰值(μ0Hm=0.01～60mT)以及频率(f=1～540Hz)的变化进行了系统的研究,发现通过在不同频率下测量χ″最大值所对应的磁场Hm(χ″),结合临界态模型的假设,可以对带材的E-J特性进行推导。在单芯带材情况下,所得结果和由传输测量得到的E-J关系相符合;而在多芯带材情况下则需要对磁化电流进行修正。这可以作为一种非接触测量单芯Bi-2223/Ag带材E-J特性的方法。

能源和水资源需求持续增长的管理选择:仅从技术科学的角度可以解决该问题吗?

能源和水资源一瞥 在未来几十年中，制定能源和水资源的世界消费模式时，不但要根据经济和人口的增长，还要考虑人们的整体消费行为。有两份背景资料也被提上了与能源有关的议事日程：1）经济和技术的努力必须改变能源消费的基础结构，将单一依赖化石燃料资源转变为部分或全部依靠其它资源；2）证实如下假设：即，尽管水力发电和核裂变有许多明显的缺陷，

Search for the rare decays W^(+)→D_(s)^(+)γ and Z→D^(0)γ at LHCb

A search for the rare decays W^(+)→D_(s)^(+)γ and Z→D0γis performed using proton-proton collision data collected by the LHCb experiment at a centre-of-mass energy of 13TeV,corresponding to an integrated luminosity of 2.0fb−1.No significant signal is observed for either decay mode and upper limits on their branching fractions are set using W^(+)→D_(s)^(+)γ and Z→μ+μ−decays as normalization channels.The upper limits are 6.5×10^(−4) and 2.1×10^(−3) at 95% confidence level for the W^(+)→D_(s)^(+)γ and Z→D^(0)γ decay modes,respectively.This is the first reported search for the Z→D^(0)γ decay,while the upper limit on the W+→D+sγbranching fraction improves upon the previous best limit.

Search for the doubly heavy baryon Ξ_(bc)^(+)→ decaying to J/ψΞ_(c)^(+)

A first search for the Ξ_(bc)^(+)J/ψΞ_(c)^(+) decay is performed by the LHCb experiment with a data sample of proton-proton collisions, corresponding to an integrated luminosity of 9 fb−1 recorded at centre-of-mass energies of 7, 8, and 13 TeV. Two peaking structures are seen with a local (global) significance of 4.3(2.8) and 4.1(2.4) standard deviations at masses of 6571 and 6694 MeV/c2, respectively. Upper limits are set on the Ξ+bc baryon production cross-section times the branching fraction relative to that of the B+c→J/ψD+s decay at centre-of-mass energies of 8 and 13 TeV, in the Ξ+bc and in the B+c rapidity and transverse-momentum ranges from 2.0 to 4.5 and 0 to 20GeV/c, respectively. Upper limits are presented as a function of the Ξ+bc mass and lifetime.

A data-driven approach to π^0,η and η＇ single and double Dalitz decays

The dilepton invariant mass spectra and integrated branching ratios of the single and double Dalitz decays P→l^＋l^-γ and P→l^＋l^-l^＋l^-（P=π^0,η,η＇;l=e or μ） are predicted by means of a data-driven approach based on the use of rational approximants applied to π^0,η and η＇ transition form factor experimental data in the space-like region.

Artificial gauge field switching using orbital angular momentum modes in optical waveguides

The discovery of artificial gauge fields controlling the dynamics of uncharged particles that otherwise elude the influence of standard electromagnetic fields has revolutionised the field of quantum simulation.Hence,developing new techniques to induce these fields is essential to boost quantum simulation of photonic structures.Here,we experimentally demonstrate the generation of an artificial gauge field in a photonic lattice by modifying the topological charge of a light beam,overcoming the need to modify the geometry along the evolution or impose external fields.In particular,we show that an effective magnetic flux naturally appears when a light beam carrying orbital angular momentum is injected into a waveguide lattice with a diamond chain configuration.To demonstrate the existence of this flux,we measure an effect that derives solely from the presence of a magnetic flux,the Aharonov-Bohm caging effect,which is a localisation phenomenon of wavepackets due to destructive interference.Therefore,we prove the possibility of switching on and off artificial gauge fields just by changing the topological charge of the input state,paving the way to accessing different topological regimes in a single structure,which represents an important step forward for optical quantum simulation.

PARTICLE DETECTORS AT ACCELERATORS

33.1. Introduction This review summarizes the detector technologies employed at accelerator particle physics experiments. Several of these detectors are also used in a non-accelerator context and examples of such applications will be provided. The detector techniques which are specific to non-accelerator particle physics experiments are the subject of Chap.

ACCELERATOR PHYSICS OF COLLIDERS

Revised August 2013 by M.J. Syphers （MSU） and F. Zimmermann （CERN）.29.1. Luminosity This article provides background for the High-Energy Collider Parameter Tables that follow. The number of events, Nexp, is the product of the cross section of interest,

ELECTROWEAK MODEL AND CONSTRAINTS ON NEW PHYSICS

Revised November 2013 by J. Erler （U. Mexico） and A. Freit＆s （Pittsburgh U.）.10.1 Introduction 10.2 Renormalization and radiative corrections

QUARK MODEL

Revised August 2013 by C. Amsler （University of Bern）, T. DeGrand （University of Colorado, Boulder）, and B. Krusche （University of Basel）.

PARTICLE DETECTORS FOR NON-ACCELERATOR PHYSICS

Updated 2013 （see the various sections for authors）.34.1. Introduction Non-accelerator experiments have become increasingly important in particle physics. These include classical cosmic ray experiments, neutrino oscillation measurements, and searches for double-beta decay, dark matter candidates, and magnetic monopoles.

Efficient option pricing with a unary-based photonic computing chip and generative adversarial learning

In the modern financial industry system,the structure of products has become more and more complex,and the bottleneck constraint of classical computing power has already restricted the development of the financial industry.Here,we present a photonic chip that implements the unary approach to European option pricing,in combination with the quantum amplitude estimation algorithm,to achieve quadratic speedup compared to classical Monte Carlo methods.The circuit consists of three modules:one loading the distribution of asset prices,one computing the expected payoff,and a third performing the quantum amplitude estimation algorithm to introduce speedups.In the distribution module,a generative adversarial network is embedded for efficient learning and loading of asset distributions,which precisely captures market trends.This work is a step forward in the development of specialized photonic processors for applications in finance,with the potential to improve the efficiency and quality of financial services.

Robust general N User authentication scheme in a centralized quantum communication network via generalized G HZ states

Quantum communication provides an enormous advantage over its classical counterpart： security of communications based on the very principles of quantum mechanics. Researchers have proposed several approaches for user identity authentication via entanglement. Unfortunately, these protocols fail because an attacker can capture some of the particles in a transmitted sequence and send what is left to the receiver through a quantum channel. Subsequently, the attacker can restore some of the confidential messages, giving rise to the possibility of information leakage. Here we present a new robust General N user authentication protocol based on N-particle Greenberger-Horne-Zeilinger （GHZ） states, which makes eavesdropping detection more effective and secure, as compared to some current authentication protocols. The security analysis of our protocol for various kinds of attacks verifies that it is unconditionally secure, and that an attacker will not obtain any information about the transmitted key. Moreover, as the number of transferred key bits N becomes larger, while the number of users for transmitting the information is increased, the probability of effectively obtaining the transmitted authentication keys is reduced to zero.

Multipartite quantum correlations among atoms in QED cavities

We study the nonlocality dynamics for two models of atoms in cavity quantum electrodynamics （QED）; the first model contains atoms in a single cavity undergoing nearest-neighbor interactions with no initial correlation, and tile second contains atoms confined in n different and noninteracting cavities, all of which were initially prepared in a maximally correlated state of n qubits corresponding to the atomic degrees of freedom. The nonlocality evolution of the states in the second model shows that the corresponding maximal violation of a multipartite Bell inequality exhibits revivals at precise times, defining, nonlocality sudden deaths and nonlocality sudden rebirths, in analogy with entanglement. These quantum correlations are provided analytically for the second model to make the study more thorough. Differences in the first model regarding whether the array of atoms inside the cavity is arranged in a periodic or open fashion are crucial to the generation or redistribution of quantum correlations. This contribution paves the way to using the nonlocality multipartite correlation measure for describing the collective complex behavior displayed by slightly interacting cavity QED arrays.

Numerical Bifurcation Methods and their Application to Fluid Dynamics: Analysis beyond Simulation

We provide an overview of current techniques and typical applications of numerical bifurcation analysis in fluid dynamical problems.Many of these problems are characterized by high-dimensional dynamical systems which undergo transitions as parameters are changed.The computation of the critical conditions associated with these transitions,popularly referred to as‘tipping points’,is important for understanding the transition mechanisms.We describe the two basic classes of methods of numerical bifurcation analysis,which differ in the explicit or implicit use of the Jacobian matrix of the dynamical system.The numerical challenges involved in both methods are mentioned and possible solutions to current bottlenecks are given.To demonstrate that numerical bifurcation techniques are not restricted to relatively low-dimensional dynamical systems,we provide several examples of the application of the modern techniques to a diverse set of fluid mechanical problems.

Tailoring thermal conductivity by engineering com- positional gradients in Sil-xGex superlattices

The transport properties of artificially engineered superlattices （SLs） can be tailored by incorporating a high density of interfaces in them. Specifically, SiGe SLs with low thermal conductivity values have great potential for thermoelectric generation and nano-cooling of Si-based devices. Here, we present a novel approach for customizing thermal transport across nanostructures by fabricating Si/Sil-xGex SLs with well-defined compositional gradients across the SiGe layer from x = 0 to 0.60. We demonstrate that the spatial inhomogeneity of the structure has a remarkable effect on the heat-flow propagation, reducing the thermal conductivity to -2.2 W.m-1.K-1, which is significantly less than the values achieved previously with non-optimized long-period SLs. This approach offers further possibilities for future applications in thermoelectricity.

Quantifying water stress effect on daily light use efficiency in Mediterranean ecosystems using satellite data

The capacity of six water stress factors(ε′(i))to track daily light use efficiency(ε)of water-limited ecosystems was evaluated.These factors are computed with remote sensing operational products and a limited amount of ground data:ε′1 uses ground precipitation and air temperature,and satellite incoming global solar radiation;ε′(2) uses ground air temperature,and satellite actual evapotranspiration and incoming global solar radiation;ε′_(3) uses satellite actual and potential evapotranspiration;ε′_(4) uses satellite soil moisture;ε′_(5) uses satellite-derived photochemical reflectance index;and ε′_(6) uses ground vapor pressure deficit.These factors were implemented in a production efficiency model based on Monteith’s approach in order to assess their performance for modeling gross primary production(GPP).Estimated GPP was compared to reference GPP from eddy covariance(EC)measurements(GPP EC)in three sites placed in the Iberian Peninsula(two open shrublands and one savanna).ε′_(i) were correlated to ε,which was calculated by dividing GPP EC by ground measured photosynthetically active radiation(PAR)and satellite-derived fraction of absorbed PAR.Best results were achieved by ε′(1),ε′(2),ε′(3) and ε′(4) explaining around 40% and 50% of ε variance in open shurblands and savanna,respectively.In terms of GPP,R^(2)≈0.70 were obtained in these cases.

Slowβrelaxation in La-based metallic glasses based on mechanical spectroscopy measurements

Dynamic mechanical relaxations of La-based metallic glasses were investigated by mechanical spectroscopy.In the framework of the mixing enthalpy of constituent atoms,it was found thatβrelaxation was less evident by the addition of Cu to replace Ni in the LaCuNiAl glassy alloy.By introducing Cu into the LaNiAl metallic glass,the mixing enthalpy was less negative,which led to weakerβrelaxation of the metallic glasses.Theαrelaxation of the La-based metallic glasses could be described by a Kohlrausch-Williams-Watts（KWW）function with a Kohlrausch exponentβKWW around 0.5.It should be noted that physical aging above the glass transition temperature Tginduced a decrease ofβrelaxation intensity in the La-based metallic glass.

BOTTOM MESONS(B=±1)B^+=u,B^0=d,B^0=db,B^-=b,similarly for B~*'s

Many measurements of B decays involve admixtures of B hadrons. Previously we arbitrarily included such admixtures in the B±section, but because of their importance we have created two new sections：