Anion-exchange membranes (AEMs) with high ion conductivity and chemical stability are urgently needed for electrochemical energy storage and conversion technologies, e.g., anion-exchange membrane fuel cells (AEMFCs), redox flow batteries, and water electrolysis cells. Herein, a series of AEMs with aryl-ether-free polymer backbones bearing long flexible alkoxy-containing bis-piperidinium cationic side chains and additional hydrophobic alkyl chains were prepared. Multiple morphology analyses confirm that such a structure can promote the self-assembly of the cationic groups. The resulting interconnected ionic highways accelerate the ion transport of AEMs, which can reach up to 122 mS cm(-1) at 80 degrees C. Moreover, the AEM shows excellent alkaline stability, with 93.4% ion conductivity remaining after aging in 2 M NaOH at 80 degrees C over 1000 h. The structural design opens an effective strategy for developing highly conductive and chemically robust AEMs.

A highly conductive anion exchange membrane with branched ionic clusters exhibits an excellent fuel cell performance of 266 mW cm−2 at 60 °C.

To access highly ion-conductive membrane materials which are urgently desired by the technologies like fuel cells, flow batteries, electro-dialysis etc., a novel polymer architecture featured by the densely grafting of three ionic strings onto each benzene ring was developed. Compared with the previous densely functionalized AEMs prepared by closely attaching multiple cations onto polymer main chain, this study aims to achieve the improved nano-phase separation ability through combing the advantages of high cation mobility and high cation density. As a result, distinct ion conducting channels were observed by atomic force microscopy and high Br(-)conductivity of 50.6 mS/cm was achieved at 80 degrees C, suggesting the effectiveness of this strategy.

The plastic deformation technologies of automotive alternator poles at home and abroad were introduced including sheet metal stamping process,cold extrusion,hot forging-cold sizing,warm-cold compound forming,back extrusion based on divided flow,hot forging-forward extrusion,hot trimming-piercing forming,as well as the short casting-forging compound forming,high speed warm extrusion,one single hot forging process.The processes used in current production have some deficiencies,such as excessive working procedures,long cycle time,huge amount of equipments and workers.However,the short forming processes of alternator poles such as casting-forging compound forming,high speed warm extrusion and one-step hot forging process,have problems of heavy forging load and short die life.Researching on methods with high efficiency,small consumption and high quality forming of alternator poles is the future development trend.

We theoretically study the electron transport properties in a ferromagnetic/normal/ferromagnetic tunnel junction, which is deposited on the top of a topological surface. The conductance at the parallel (P) configuration can be much bigger than that at the antiparallel (AP) configuration. Compared P with AP configuration, there exists a shift of phase which can be tuned by gate voltage. We find that the exchange field weakly affects the conductance of carriers for P configuration but can dramatically suppress the conductance of carriers for AP configuration. This controllable electron transport implies anomalous magnetoresistance in this topological spin valve, which may contribute to the development of spintronics. In addition, there shows an existence of Fabry-Perot-like electron interference in our model based on the topological insulator, which does not appear in the same model based on the two dimensional electron gas.

For micro-mechanical resonator capacitance signal is difficult to detect, this paper adopts one-port electrostatic excitation and ca-pacitive detection method based on the frequency separation, coupling with the isolation transformer application technology. The measurement is time-continuous and only requires a very simple resonant structure where a single electrode is simultaneously used for excitation and detection. This method solves the problem of electrical cross-talk in two-port resonator under same-frequency excitation. On the basis of building the platform of excitation/detection system, the experiments were carried out and the third harmonic of the output current can be observed. The vibra-tion information of the resonator can be obtained through dealing the information of the third harmonic, which verifies the validity of the entire method. It is a foundation for realizing closed-loop of the resonator in the future.

Exciton effects on the linear and nonlinear optical absorptions (the transition from the S state (L=0) to the P state (L=1)) in two-dimensional quantum dots are theoretically studied by using the configuration-integration methods (CI) and the compact density-matrix approach. The results show that the optical absorption coefficient, which can be controlled by the confinement potential strength and the incident optical intensity, is enhanced obviously when the exciton effect is taken into account. We find that both a trapped electron–hole pair and the incident optical intensity can bleach the exciton absorption and the appearance of the new absorption may be due to biexciton.

A single stage hot forging process and die set of alternator poles are put forward in this paper, the heated billet can be forged by only one press in a special die set, which has a moveable mandrel and ring die. The process is analyzed by finite element method(FEM) and experiment. The effects of mandrel on the mode of metal flow and forging load are discussed. The result shows that a well-shaped product can be forged successfully using a lower forging load than that of conventional precision forging.

In order to resolve the defects that exist in conventional manufacture of bearing inner and outer rings,such as low material utilization,too many work steps and low quality,a combined warm extrusion process and its die were put forward.An extrusion part could be obtained by combined warm extrusion in one step,and the bearing inner ring and outer ring could be obtained by two step blanking based on the extrusion part.Finite element method was used to analyze the combined warm extrusion process.The results show that an extrusion part with precise size and high quality can be obtained by the upper and lower clamping device and appropriate pressure.

We investigate the energy-level shift of a hydrogen atom in a two-dimensional optical microcavity, where there exists a Bose—Einstein condensation of photons. It is found that below the critical temperature Tc, the energy-level shift of the bound electron is dependent on temperature, and it is a monotonically increasing function of the absolute temperature T. Especially, at the absolute zero temperature, the energy-level shift entirely comes from the Lamb shift, and the atom can be treated approximately, that is, in vacuum.

We analyze the ground-state properties and the excitation spectrum of Bose-Einstein condensates of photons and PPs in a two-dimensional optical microcavity. First, using the variational method, we discuss the ground-state phase transition of the two-component system. We also investigate the energy gap between the ground state and the first excited state. Moreover, by investigating the excitation spectrum, we also illustrate how the superfluid behavior of photons and PPs can be associated with the phase transition of the system.

Bose–Einstein condensation of a weakly interacting photon gas in a two-dimensional optical microcavity is investigated. The effective mass and chemical potential for a photon confined inside this optical microcavity are non-vanishing. A reservoir theory has been used to study the decay rate of a two-level atom in the microcavity, in which photons are in the Bose–Einstein condensate state. It is found that below the critical temperature Tc, the atomic decay rate is a monotonically increasing function of the absolute temperature T.

In this paper, we investigate the transport features and the Fano factor of Dirac electrons on the surface of a three-dimensional topological insulator with a magnetic modulation. We consider a hard wall bounding condition on the edge of the topological insulator, which implies that a surface state of the topological insulator is insulating. We find that a valley of conductivity at the Dirac point is associated with a Fano factor peak, and more interestingly, this topological metal changes from insulating to metallic by controlling the effective exchange field.

We investigate the Bose-Einstein condensation of photons and photon pairs in a two-dimension optical microcavity. We find that in the paraxial approximation, the mixed gas of photons and photon pairs is formally equivalent to a two dimension system of massive bosons with non-vanishing chemical potential, which implies the existence of two possible condensate phase. We also discuss the quantum phase transition of the system and obtain the critical point analytically. Moreover, we find that the quantum phase transition of the system can be interpreted as second harmonic generation.

We investigate the decay rate of an atom in a two-dimensional optical microcavity in which there exists a Bose-Einstein condensation of photons. It is found that below the critical temperature T-c., the atomic decay rate depends on the absolute temperature T. Especially, at absolute zero temperature almost all photons are in the condensate state, and the atom can be approximately treated as if it is in vacuum.

Mixed structure of amorphous-nanocystalline phases with several nanometers was found on impacted surface of a medium carbon steel with HRTEM.The amorphous distributes in ribbon along surface of microcrack formed during impact wearing.The calculation results show that a new mechanism of amorphous formation is in effect possibly under impact load,and the nanocystalline can transform into amorphous.The microcrack surface is the priority site for amorphous formation,which is accordance with the experimental result,and interface energy is main driving force for amorphous formation.The calculation result shows that the amorphous can occur at the inside of materials with higher resistance,and it is very difficult for a high density dislocations zone directly to transform into the amorphous without nanocystallines formation.

Based on analysis of the characteristics of upper ejector stamping die,the features of reclaiming device were pointed out.A kind of automatic reclaiming device based on the connecting rod was designed.Sliding block of the press was taken as power source of the device,which can be used in different die height.The motion simulation was carried out in Pro/Engineering,which shows the validity of the reclaiming device in upper ejector stamping die.

We study magnetic field modulated transport properties of Dirac fermions in graphene, where Dirac fermions penetrate through a velocity barrier. We find strong wave vector filtering and resonant effect. The angular-dependent region of resonant tunneling is suppressed by tuning velocity barriers. We can also found that the confined states in this velocity barrier can be changed by the magnetic field. Various novel devices, such as wavevector filter and magnetic switches, may be constructed based on our observed phenomena.

Considering the attractive interaction between two magnons with opposite wave vectors in a Heisenberg ferromagnet, we propose the model of magnon-pairs, which is suitable for low-temperature environment. A dressed magnon is an energy quantum of the magnon-pairs whose energy is a monotonically increasing function of absolute temperature. Based on the model, we re-investigate the excitation mechanism and thermodynamic properties of the Heisenberg ferromagnet. The correction factor e(0) plays an important role in studying the low-temperature properties of a ferromagnet.