Magnetic field effect in photodetachment from negative ion in electric field near metal surface

Based on the closed-orbit theory, the magnetic field effect in the photodetachment of negative ion in the electric field near a metal surface is studied for the first time. The results show that the magnetic field can produce a significant effect on the photodetachment of negative ion near a metal surface. Besides the closed orbits previously found by Duet al. for the H in the electric field near a metal surface （J. Phys. B 43 035002 （2010））, some additional closed orbits are produced due to the effect of magnetic field. For a given ion surface distance and an electric field strength, the cross section depends sensitively on the magnetic field strength. As the magnetic field strength is very small, its influence can be neglected. With the increase of the magnetic field strength, the number of the closed orbits increases greatly and the oscillation in the cross section becomes much more complex. Therefore we can control the photodetachment cross section of the negative ion by changing the magnetic field strength. We hope that our results may guide future experimental studies for the photodetachment process of negative ion in the presence of external fields and surfaces.

The Magnetic Field Effect on the Polymerization of Styrene in Supercritical Carbon Dioxide

Styrene was polymerized in supercritical （sc） CO2 with benzoyl peroxide （BPO） as initiator. It was found that the polymerization was accelerated by the external magnetic field.

In situ FTIR Investigation of Magnetic Field Effect on Heterogeneous Photocatalytic Degradation of Benzene over Pt/TiO_(2)

In situ FTIR spectroscopy was utilized to investigate the magnetic field effect on the heterogeneous photocatalytic degradation of benzene over platinized titania （Pt/TiO2）. The results revealed that the employment of magnetic field may not change the mechanism of photocatalytic degradation of benzene, however, it greatly facilitate the conversion of benzene to phenol and quinone, as well as the transformation from phenol to quinone, resulting in opening the benzene ring easily and promoting the production of CO2.

Lattice Boltzmann Simulation of Magnetic Field Effect on Electrically Conducting Fluid at Inclined Angles in Rayleigh-Bénard Convection

The magneto-hydrodynamics(MHD)effect is studied at different inclined angles in Rayleigh-Bénard(RB)convection inside a rectangular enclosure using the lattice Boltzmann method(LBM).The enclosure is filled with electrically conducting fluids of different characteristics.These characteristics are defined by Prandtl number,Pr.The considered Pr values for this study are 10 and 70.The influence of other dimensionless parameters Rayleigh numbers Ra=10^(3);10^(4);10^(5);10^(6) and Hartmann numbers Ha=0,10,25,50,100,on fluid flow and heat transfer,are also investigated considering different inclined anglesφof magnetic field by analyzing computed local Nusselt numbers and average Nusselt numbers.The results of the study show the undoubted prediction capability of LBM for the current problem.The simulated results demonstrate that the augmentation in heat transfer is directly related to Ra values,but it is opposite while observing the characteristics of Ha values.However,it is also found thatφhas a significant impact on heat transfer for different fluids.Besides,isotherms are found to be always parallel to the horizontal axis at Ra=10^(3) as conduction overcomes the convection in the heat transfer,but this behaviour is not seen at Ra=10^(4) when Ha>25.Furthermore,at Ra=10^(6),oscillatory instability appears but LBM is still able to provide a complete map of this predicted behavior.An appropriate validation with previous numerical studies demonstrates the accuracy of the present approach.

MAGNETIC FIELD EFFECT ON PHOTOPOLYMERIZATION OF STYRENE MICROEMULSION

External magnetic field increases the photo-induced polymerization rate of styrene microemulsion.The type of photoinitiator plays an important role. The photoinitiators, used are dimethoxyphenyl acetophenone(DMPA), 1-hydroxycyclohexyl phenylketone (Irgacure 184) and dimethylhydroxyacetophenone (Darocur 1173). No magnetic effect was observed by using dibenzylketone (DBK) as photoinitiator. The molecular weight of the polymer is slightly affected by magnetic field. The influence of temperature has also been investigated.

Magnetic Field Effects on Photoreduction Reaction of 2-Methyl-1,4-Naphthoquinone in Brij 35 Micellar Solution with Additional Radical

A study was made of magnetic field effects (MFEs) on the photoreduction reaction of 2-methyl-1,4-naphthoqui- none (MNQ) in Brij 35 micellar solution containing 4-lauroylamino-TEMPO (2,2,6,6-tetramethylpiperidine-1-oxyl) radical (L-R) under magnetic fields below 1.75 T by a nanosecond laser flash photolysis technique. The triplet MNQ mainly underwent the hydrogen abstraction from Brij 35 molecule to give a radical pair. The escaped radical yield increased with magnetic fields from 0 to 0.62 T and then saturated from 0.62 to 1.75 T. MFEs for both sys-tems can be explained by the relaxation mechanism. However, it was supposed that additional radical, L-R affected the MFEs mainly through enhancing the spin-spin interactions of radical pairs. The effect of the micelle size on MFEs of the studying system was also discussed.

The Effects of Magnetic Fields on Swing Amplifier

The excitation and evolution of magnetohydrodynamic density waves are considered in a differentially rotating thin gaseous disk embedded with both an azimuthal magnetic field and a vertical magnetic field perpendicular to the disk. Our results shows that the effect of isopedic vertical magnetic fields tend to stabilize the fast MHD density waves while slow MHD density waves are not affected by such vertical magnetic fields for either rigid or differential rotation.

Effects of Pure Dzyaloshinskii-Moriya Interaction with Magnetic Field on Entanglement in Intrinsic Decoherence

We investigate the effects of pure Dzyaloshinskii Moriya （DM） interaction with magnetic field on entanglement in intrinsic decoherence, assuming that the system is initially in four Bell states ｜φ±〉 = （｜00） ± ｜11〉）/√2 and ｜ψ±〉 = （｜01） ±｜10〉）/√2, respectively. It is found that if the system is initially in the state p1（0） = ｜φ＋〉〈φ＋1, the entanglement can obtain its maximum when the DM interaction vector D is in the plane of XOZ and magnetic field B = By with the infinite time t, moreover the entanglement is independent of By and t when By is perpendicular to D. In addition, we obtain similar results when the system is initially in the states p2（0） = ｜φ-〉〈φ-｜ or p3 （0） = ｜ψ＋〉〈ψ＋1. However, we find that if the system is initially in the state P4 （0） = ｜ψ-〉〈ψ-l, the entanglement can obtain its maximum for infinite t, when the DM vector is in the plane ofYOZ, XOZ, or XOY, with the magnetic field parallel to X, Y, or Z axis, respectively. Moreover, when the axial B is perpendicular to D for the initial state p4（O）, the negativity oscillates with time t and reaches a stable value, the larger the value of B is, the greater the stable value is, and the shorter the oscillation time of the negativity is. Thus we can adjust the direction and value of the external magnetic field to obtain the maximal entanglement, and avoid the adverse effects of external environment in some initial state. This is feasible within the cun＇ent experimental technology.

Combined Effect of Uniaxial Strain and Magnetic Field on the Exciton States in Semiconducting Single-Walled Carbon Nanotubes

The exciton states of semiconducting carbon nanotubes are calculated by a tight-binding model supplemented by Coulomb interactions under the combined effect of uniaxial strain and magnetic field. It is found that the excitation energies and absorption spectra of zigzag tubes（11,0） and（10,0） show opposite trends with the strain under the action of the magnetic field. For the（11,0） tube, the excitation energy decreases with the increasing uniaxial strain, with a splitting appearing in the absorption spectra. For the（10,0） tube, the variation trend firstly increases and then decreases, with a reversal point appearing in the absorption spectra. More interesting,at the reversal point the intensity of optical absorption is the largest because of the degeneracy of the two bands nearest to the Fermi Level, which is expected to be observed in the future experiment. The similar variation trend is also exhibited in the binding energy for the two kinds of semiconducting tubes.

Effect of gradient magnetic field on physiochemistry functions of rice seedlings

Rice varieties Handao 2,Zhongbai 4,Han-jingzi,and Akihikari were treated with gradi-ent magnetic fileld to study the effect of gradi-ent field on rice.The magnetic field was madeup of 12 plots magnetic plates arranged in eachother south and north pole.The magneticstrength was 0-40 mT.Each four varieties wasput under the magnetic plate 15 cm away,andwent through the magnetic field with the speedof 20 cm/s.The same varieties without thetreatment were used as CK.Both of the seedswere soaked in water for 48 h in room temper-ature,and then sprouted on the porcelain platewith absorbed water paper.When the

INFLUENCE OF EXTERNAL MAGNETIC FIELD ON THE FLOW FIELD IN MOLTEN SEMICONDUCTOR OF CZOCHRALSKI CRYSTAL GROWTH——A NUMERICAL SIMULATION

Numerical results show that an external magnetic field may influence significantly the flow pattern in the molten semiconductor of Czochralski crystal growth. The melt flow could be pronouncedly damped by a magnet. ic field with the intensity of several thousands Gauss, while the temperature field is affected only in a less extent by the magnetic field.

Oxygen Incorporation in Czochralski Growth of Silicon under a Horizontal Magnetic Field

A mechanism of oxygen transportation in Czochralski growth of silicon crystals under a horizontal magnetic field (HMCZ) is proposed. Oxygen depleted surface melt, driven to the growth interface by the thermal Marangoni flow, determines oxygen concentration in the grown crystals. Systematic study was carried out to investigate effects of growth parameters on oxygen incorporation into crystals.

Local magneto-optical Kerr effect imaging by scanning near-field optical microscope in reflection-mode

A method for local magneto-optical Kerr effect imaging based on a home-made scanning near-field optical microscope working in reflection mode is presented. Shear force detection is carried out by using a symmetric piezoelectric bimorph sensor, which provides an easy way not only for probe-surface distance control but also for imaging. Polarization-preserving fiber probes used as a local optical detector are fabricated with a heating-pulling technique and the probes＇ polarization properties are measured. Shear force topographic and near-field magneto-optical images of magueto-optical disk taken with the proposed method are shown.

Comparative Observation of Ar,Ar-H_2 and Ar-N_2 DC Arc Plasma Jets and Their Arc Root Behaviour at Reduced Pressure

Results observed experimentally are presented, about the DC arc plasma jets and their arc-root behaviour generated at reduced gas pressure without or with an applied magnetic field. Pure argon, argon-hydrogen or argon-nitrogen mixture was used as the plasma-forming gas. A specially designed copper mirror was used for a better observation of the arc-root behaviour on the anode surface of the DC non-transferred arc plasma torch. It was found that in the cases without an applied magnetic field, the laminar plasma jets were stable and approximately axisymmetrical. The arc-root attachment on the anode surface was completely diffusive when argon was used as the plasma-forming gas, while the arc-root attachment often became constrictive when hydrogen or nitrogen was added into the argon. As an external magnetic field was applied, the arc root tended to rotate along the anode surface of the non-transferred arc plasma torch.

Progress in organic spintronics

Recent progress in organic spintronics is given an informative overview, covering spin injection, detection, and trans-port in organic spin valve devices, and the magnetic field effect in organic semiconductors （OSCs）. In particular, we focus on our own recent work in spin injection and the organic magnetic field effect （OMFE）.

Numerical investigation of radio-frequency negative hydrogen ion sources by a three-dimensional fluid model

A three-dimensional fluid model is developed to investigate the radio-frequency inductively coupled H2 plasma in a reactor with a rectangular expansion chamber and a cylindrical driver chamber,for neutral beam injection system in CFETR.In this model,the electron effective collision frequency and the ion mobility at high E-fields are employed,for accurate simulation of discharges at low pressures(0.3 Pa-2 Pa)and high powers(40 kW-100 kW).The results indicate that when the high E-field ion mobility is taken into account,the electron density is about four times higher than the value in the low E-field case.In addition,the influences of the magnetic field,pressure and power on the electron density and electron temperature are demonstrated.It is found that the electron density and electron temperature in the xz-plane along permanent magnet side become much more asymmetric when magnetic field enhances.However,the plasma parameters in the yz-plane without permanent magnet side are symmetric no matter the magnetic field is applied or not.Besides,the maximum of the electron density first increases and then decreases with magnetic field,while the electron temperature at the bottom of the expansion region first decreases and then almost keeps constant.As the pressure increases from 0.3 Pa to 2 Pa,the electron density becomes higher,with the maximum moving upwards to the driver region,and the symmetry of the electron temperature in the xz-plane becomes much better.As power increases,the electron density rises,whereas the spatial distribution is similar.It can be summarized that the magnetic field and gas pressure have great influence on the symmetry of the plasma parameters,while the power only has little effect.

Tunneling-induced π-phase shift with a single-photon signal field in asymmetric double quantum wells

A theoretical investigation is carried out into the cross phase modulation （XPM） in an asymmetric double A1GaAs/GaAs quantum wells structure with a common continuum. It is found that, combining resonant tunneling-induced transparency and constructive interference in the third-order Kerr effect, a giant XPM can be achieved with vanishing linear and nonlinear absorptions, accompanied by the velocities of the probe and signal fields being matched. Furthermore, this giant XPM could induce a π-phase shift at a single-photon level which is favorable for the applications in two-qubit quantum logic gates.

Spin-Enhanced C-C Coupling in CO_(2)Electroreduction with Oxide-Derived Copper

Electrocatalytic reduction of carbon dioxide(CO_(2))to multicarbon(C2+)products involves intricate multiple protons and electron transfer of C-C coupling,which is dictated by not only the intrinsic reactivity but also the spin states of electrons in the catalyst.Here,we observe spin-enhanced CO_(2)reduction(CO_(2)RR)electrocatalytic activity on an oxidederived copper(OD-Cu)catalyst due to the existence of a specific Cu*site that carried the magnetic moments.Due to the correlation of magnetic and catalytic properties in OD-Cu,the current density through the OD-Cu electrode increases by nearly 10%at 350 mT.The field strength and angle dependence of such magnetic field effect(MFE),together with the time-resolved measurements proved that it originated from the alignment of magnetic moments on Cu*sites.The MFE on the electrocatalytic process enabled an enhancement(up to 15%)of the CO_(2)RR Faradaic efficiency using the OD-Cu catalyst.Importantly,the enhancement was attributed to the spinantiparallel alignment of electrons to promote C-C coupling on asymmetric Cu*-Cu sites;consequently,the optimal bias was reduced by∼0.2 V under the magnetic field for C2 products with Faradaic efficiency>30%and selectivity>75%.Our work uncovers a new paradigmfor spin-enhanced catalysis applicable to a broad range of chemical reactions involving spin singlet products.

Unconventional strategies to break through the efficiency of light-driven water splitting:A review

Semiconductor-based solar-driven water splitting technology is an environmentally friendly and cost-effective approach for the production of clean fuels.The overall solar-to-hydrogen efficiency of semiconductorbased photo(electro)catalysts is jointly determined by factors,such as light absorption efficiency of the photo(electro)catalysts,internal separation efficiency of charge carriers,and injection efficiency of surface charges.However,the traditional improvement strategies,such as morphology control,functional layer modification,and band alignment engineering,still have certain limitations in enhancing the conversion efficiency of the photo(electro)catalytic water splitting.Recently,unconventional enhancement strategies based on surface plasmonic effects,piezoelectric effects,thermoelectric effects,and magnetic effects have provided unique pathways for improving the solar-to-hydrogen efficiency of photo(electro)catalysts.Therefore,this review outlines the fundamental concepts of these physical effects and elucidates their intrinsic mechanisms in enhancing the efficiency of photo(electro)catalysts for water splitting process through practical application examples.Ultimately,the future development of unconventional strategies for enhancing photo(electro)catalytic water splitting is envisioned.