A porous puckered V_(2)O_(5) polymorph as new high performance cathode material for aqueous rechargeable zinc batteries

Aqueous rechargeable zinc batteries are getting increasing attention for large-scale energy storage owing to their advantages in terms of cost,environmental friendliness and safety.Here,the layered puckeredγ’-V_(2)O_(5) polymorph with a porous morphology is firstly introduced as cathode for an aqueous zinc battery system in a binary Zn^(2+)/Li^(+)electrolyte.The Zn‖γ’-V_(2)O_(5) cell delivers high capacities of 240 and190 mAh g^(-1) at current densities of 29 and 147 mA g^(-1),respectively,and remarkable cycling stability in the 1.6 V-0.7 V voltage window(97%retention after 100 cycles at 0.15 A g^(-1)).The detailed structural evolution during first discharge-charge and subsequent cycling is investigated using X-ray diffraction and Raman spectroscopy.We demonstrate a reaction mechanism based on a selective Li insertion in the1.6 V-1.0 V voltage range.It involves a reversible exchange of 0.8 Li^(+)in γ’-V_(2)O_(5) and the same structural response as the one reported in lithiated organic electrolyte.However,in the extended 1.6 V-0.7 V voltage range,this work puts forward a concomitant and gradual phase transformation from γ’-V_(2)O_(5) to zinc pyrovanadate Zn_(3)V_(2)O_(7)(OH)2.2 H_(2)O(ZVO)during cycling.Such mechanism involving the in-situ formation of ZVO,known as an efficient Zn and Li intercalation material,explains the high electrochemical performance here reported for the Zn‖γ’-V_(2)O_(5) cell.This work highlights the peculiar layered-puckeredγ’-V_(2)O_(5) polymorph outperforms the conventionalα-V_(2)O_(5) with a huge improvement of capacity of 240 mAh g^(-1)vs 80 mAh g^(-1) in the same electrolyte and voltage window.

Chip-Based Square Wave Dynamic Micro Atom Trap

我们为陷井潜力被方形的波浪放射和一个不同类的静态的磁场创造的一个基于薄片的动态微原子陷井建议一个计划。这种陷井数组的参数能动态地被调制。两一个维(1-D ) 并且二维(2-D ) 为 6Li 原子的陷井数组潜力被讨论。1-D 陷井被方形的波浪放射(6 kHz ) 和一个坡度磁场(300 G/cm ) 联合， 1-D 陷井的数组常数是 0.85 公里。因为陷井数组不要求任何激光域，它能在一块芯片上是容易综合的，它在可伸缩的量信息处理的应用程序是有用的。[从作者抽象]

Quantum Computation with Two-Level Systems in Current-Biased Josephson Junction

我们在场在现在的试验性的技术下面在偏导水流的 Josephson 连接(CBJJ ) 用二水平的系统(TLS ) 认识到量计算的一个可行计划。由用作收款机 qubit 的 CBJJ 的 TLS 的有效操作能被获得，例如初始化， single-qubit 旋转， two-qubit 门，纠纷产生，并且读出，等等。另外，我们也讨论计划的试验性的可行性和效率。

Effects of Colored Noise on Periodic Orbits in a One-Dimensional Map

噪音能导致反的加倍时期的转变和混乱。在逻辑地图的不同周期的序列，周期的轨道上的有颜色的噪音的效果被调查。这被发现轨道的动态行为，由指数地相关的有颜色的噪音导致了，在他们的动态行为上的噪音紧张的转变，和效果的合并是不同的与噪音的关联时间的效果不同。显著地，也就是，噪音能导致新周期的轨道二条新轨道出现在时期--在分叉参数值=的四个序列 3.5 ，在时期的四条新轨道--在=的八个序列 3.55 ，并且在时期的三条新轨道--在=的六个序列 3.846 分别地。而且，新轨道的动态行为清楚地显示出 resonancelike 反应到有颜色的噪音。

Spin-dependent negative differential conductance in transport through single-molecule magnets

Transport properties are theoretically studied through an anisotropy single-molecule magnet symmetrically connected to two identical ferromagnetic leads. It is found that even though in parallel configuration of leads’ magnetizations, the total current still greatly depends on the spin polarization of leads at certain particular bias region, and thus for large polarization a prominent negative differential conductance （NDC） emerges. This originates from the joint effect of single-direction transitions and spin polarization, which removes the symmetry between spin-up and spin-down transitions. The present mechanism of NDC is remarkably different from the previously reported mechanisms. To clarify the physics of the NDC, we further monitored the shot noise spectroscopy and found that the appearance of the NDC is accompanied by the rapid decrease of Fano factor.

Microstructural evolution of a recycled aluminum alloy deformed by equal channel angular pressing process

The microstructural evolution of a recycled aluminum alloy after equal channel angular pressing （ECAP） up to four passes was investigated using X-ray diffxaction （XRD） analysis and transmission electron microscopy （TEM）. Microhardness tests were performed to determine the associated changes in mechanical properties. An ultrafine-grained material has been obtained with a microstructure showing a mixture of highly strained crystallites. A high density of dislocations was achieved as a result of severe plastic deformation （SPD） through the die. Changes in mechanical behavior are also revealed after ECAP due to strain hardening. Thermal analysis and TEM micrographs ob- tained after annealing indicate the succession of the recovery, recrystallization, and grain growth phenomena. Moreover, the energy stored during ECAP may be related to the dislocation density introduced by SPD. We finally emphasize the role played by the precipitates in this alloy.

Locally Accessible Information from Multipartite Ensembles

我们在场为任意的多国参加的整体的局部地可存取的信息上的通用象 Holevo 一样上面的界限。这界限允许我们分析在里面在本地操作和古典通讯下面的一套直角的状态的可区别性。我们也为与多国参加的发送者和多国参加的接收装置的分布式的稠密的编码的能力导出上面的界限。

The Vision of France, Germany, and the European Union on Future Hydrogen Energy Research and Innovation

Hydrogen(H2)is an essential vector for freeing our societies from fossil fuels and effectively initiating the energy transition.Offering high energy density,hydrogen can be used for mobile,stationary,or industrial applications of all sizes.This perspective on the crucial role of hydrogen is shared by a growing number of countries worldwide(e.g.,China,Germany,Japan,Republic of Korea,Australia,and United States),which are publishing ambitious roadmaps for the development of hydrogen and fuel cell technologies,supported by substantial financial efforts.

Implementation of a Quantum Conditional Phase Gate for the Quantum Fourier Transform in Circuit QED

联合到一个传播线共鸣器的多重超导的费用 qubits 能被控制完成在二任意的 qubits 之间的量逻辑门，是众所周知的。我们建议一个计划认识到量有由电路的一个几何性质的有条件的阶段门 electrodynamics，和它自然地被使用与高保真度认识到量 Fourier 变换。申请在现在的试验性的技术下面可行、可观，这也被表明。[从作者抽象]

All-electric-controlled spin current switching in single-molecule magnet-tunnel junctions

A single-molecule magnet （SMM） coupled to two normal metallic electrodes can both switch spin-up and spin- down electronic currents within two different windows of SMM gate voltage. Such spin current switching in the SMM tunnel junction arises from spin-selected single electron resonant tunneling via the lowest unoccupied molecular orbit of the SMM. Since it is not magnetically controlled but all-electrically controlled, the proposed spin current switching effect may have potential applications in future spintronics.

Resonant tunneling through double-barrier structures on graphene

Quantum resonant tunneling behaviors of double-barrier structures on graphene are investigated under the tight- binding approximation. The Klein tunneling and resonant tunneling are demonstrated for the quasiparticles with energy close to the Dirac points. The Klein tunneling vanishes by increasing the height of the potential barriers to more than 300 meV. The Dirac transport properties continuously change to the Schr6dinger ones. It is found that the peaks of resonant tunneling approximate to the eigen-levels of graphene nanoribbons under appropriate boundary conditions. A comparison between the zigzag- and armchair-edge barriers is given.

Efficient Phase-Encoding Quantum Key Generation with Narrow-Band Single Photons

We propose an efficient phase-encoding quantum secret key generation scheme with heralded narrow-band single photons.The key information is carried by the phase modulation directly on the single-photon temporal waveform.We show that when the technique is applied to the conventional single photon phase-encoding BB84 and differential phase shift(DPS)quantum key distribution schemes,the key generation efficiencies can be improved by factors of 2 and 3,respectively.For N(≥3)−period DPS systems,the key generation efficiency can be improved by a factor of N.The technique is suitable for quantum-memory-based long-distance fiber communication systems.

Majorana fermion realization and relevant transport processes in a triple-quantum dot system

Nonequilibrium electronic transports through a system hosting three quantum dots hybridized with superconductors are investigated. By tuning the relative positions of the dot levels, we illustrate the existence of Majorana fermions and show that the Majorana feimions will either survive separately on single dots or distribute themselves among different dots with tunable probabilities. As a result, different physical mechanisms appear, including local Andreev reflection（LAR）,cross Andreev reflection（CAR）, and cross resonant tunneling（CRT）. The resulting characteristics may be used to reveal the unique properties of Majorana fermions. In addition, we discuss the spin-polarized transports and find a pure spin current and a spin filter effect due to the joint effect of CRT and CAR, which is important for designing spintronic devices.

AB_(2)-type rare earth-based compounds with C-15 structure:Looking for reversible hydrogen storage materials

AB_(2)-type(A=rare earth,B=transition metal)intermetallic compounds with C15 structure can easily absorb large amount of hydrogen,showing their potential use as hydrogen storage materials.The crucial problem hindering their application is hydrogen induced amorphization(HIA),which leads to the irreversible hydrogen sorption process.The stability of the AB_2 Laves phase compounds,the structural properties,the hydrogenation properties and the controlling factors of HIA are discussed in this review.Comparing with other factors,the atomic radii ratio r_A/r_B is the most important one influencing the HIA.Multi-element substitution is an efficient way to suppress or limit HIA and may enable AB_2 compounds to be suitable for hydrogen storage.

Hydrogen storage properties of Li-Mg-N-B-H/ZrCoH_(3) composite with different ball-milling atmospheres

Li-Mg-N-B-H/ZrCoH_(3) composites were successfully synthesized by ball milling of the reactants under argon and hydrogen atmosphere,respectively.The composite synthesized by reactive ball milling(RBM)under hydrogen has the best hydrogen storage properties.It can desorb 3.71 wt%hydrogen in 60 min at 150℃under pressure of 0.1 MPa,and the dehydrogenation capacity reaches 4.59 wt%in 8 h.For the re-hydrogenation,5.27 wt%hydrogen was absorbed in only 10 min at 150℃under H_(2) pressure of 8 MPa.The phases of the as-milled and subsequently dehydrogenated and re-hydrogenated samples were determined by X-ray diffraction(XRD).The microstructures and elemental distributions were characterized by scanning electron microscope(SEM)and energy-dispersive spectrometer(EDS)measurements.It is shown that Mg is in situ hydrogenated and introduced homogeneous distribution of ZrCoH_(3) particles during the RBM process under hydrogen atmosphere.The activation energies for the composites were calculated by Kissinger method through differential scanning calorimetric(DSC)measurements for the dehydrogenation process with different heating rates.It is determined that the activation energy for the Li-Mg-N-B-H/ZrCoH_(3) composite synthesized by RBM under hydrogen is 79.9 kJ·mol^(-1),which is14 kJ·mol^(-1) lower than that for the sample without ZrCoH_(3) addition.The N-H bond energies were analyzed by infrared(IR)absorption spectrum,and the reasons for weakening of the N-H bond were further discussed.

Heat treatment effect on structural evolution and hydrogen sorption properties of Y_(0.5)La_(0.2)Mg_(0.3-x)Ni_(2) compound

The effect of heat treatment on phase occurrence,crystal structures and hydrogen sorption properties of Y_(0.5)La_(0.2)Mg_(0.3-x)Ni_(2) compounds has been investigated.The targeted compounds were synthesized through induction melting and processed heat treatment at 700 and 900℃,respectively.Phase occurrence and structural properties were studied by X-ray powder diffraction(XRD).The global compositions and phase compositions have been determined by inductively coupled plasma-optical emission spectrometer(ICP-AES) and electron probe microanalysis(EPMA) respectively.

Electron microscopy methods for space-, energy-, and time-resolved plasmonics

Nanoscale plasmonic systems combine the advantages of optical frequencies with those of small spatial scales, circumventing the limitations of conventional photonic systems by exploiting the strong field confinement of surface plasmons. As a result of this miniaturization to the nanoscale, electron microscopy techniques are the natural investigative methods of choice. Recent years have seen the development of a number of electron microscopy techniques that combine the use of electrons and photons to enable unprecedented views of surface plasmons in terms of combined spatial, energy, and time resolution. This review aims to provide a comparative survey of these different approaches from an experimental viewpoint by outlining their respective experimental domains of suitability and highlighting their complementary strengths and limitations as applied to plasmonics in particular.

Synthesis,sintering,and thermoelectric properties of the solid solution La_(1–x)Sr_(x)CoO_(3±δ)(0≤x≤1)

In this work, we synthesized cubic perovskite ceramics of the whole La_(1–x)Sr_xCoO_3(0 ≤ x ≤ 1) solid solution for the first time. Synthesis was carried out by solid state reaction and conventional sintering to reach dense ceramics. For x > 0.8, it was necessary to substitute 3% cobalt by silicon to stabilize the cubic perovskite structure. Electrical conductivity increased with Sr content to reach 3×10~5 S·m^(–1) at 330 K for x = 0.3. However, the optimum electrical properties have been found for x = 0.05 at 330 K with PF_(max) = 3.11×10^(–4)W·m^(–1)·K^(–2). Indeed, the Seebeck coefficient was decreasing when x increased to reach values close to 0 for x ≥ 0.3. Thermal conductivity was low at low temperature(≈ 2.5 W×m^(–1)·K^(–1)) and increased up to 6.5 W·m^(–1)·K^(–1) when temperature increased. As the highest power factor was reached at low temperature as well as the lowest thermal conductivity, La_(1–x)Sr_xCoO_3 compounds with low x values appeared as very promising thermoelectric materials around room temperature, on the contrary to layered cobalt oxides. For high x values, Seebeck coefficient values close to zero made these materials unsuitable for thermoelectric applications.

Magnetically Controlled Electronic Transport Properties of a Ferromagnetic Junction on the Surface of a Topological Insulator

We have investigated the transport properties of the Dirac fermions through a ferromagnetic barrier junction on the surface of a strong topological insulator.The current-voltage characteristic curve and the tunneling conductance are calculated theoretically.Two interesting transport features are predicted:observable negative differential conductances and linear conductances tunable from unit to nearly zero.These features can be magnetically manipulated simply by changing the spacial orientation of the magnetization.Our results may contribute to the development of high-speed switching and functional applications or electrically controlled magnetization switching.