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Magnetar is a kind of pulsar powered by magnetic field energy. Part of the X-ray luminosities of magnetars in quiescence have a thermal origin and can be fitted by a blackbody spectrum with temperature kT ～ 0.2－0.6 keV, much higher than the typical values for rotation-powered pulsars. The observation and theoretical study of magnetar are one of hot topics in the field of pulsar research. The activity and emission characteristics of magnetar can be attributed to internal superhigh magnetic field. According to the work of WGW19 and combining with the equation of state, we first calculate the electric conductivity of the crust under a strong magnetic field, and then calculate the toroidal magnetic field decay rate and magnetic energy decay rate by using an eigenvalue equation of toroidal magnetic field decay and considering the effect of general relativity. We reinvestigate the LX-Lrot relationship of 22 magnetars with persistent soft X-ray luminosities and obtain two new fitting formulas on LX-Lrot. We find that for the magnetars with LX < Lrot, the soft X-ray radiations may originate from their rotational energy loss rate, or from magneto-sphere flow and particle wind heating. For the magnetars with LX > Lrot, the Ohmic decay of crustal toroidal magnetic fields can provide their observed isotropic soft X-ray radiation and maintain higher thermal temperature.As for the initial dipole magnetic fields of magnetars, we mainly refer to the rersearch by Viganò et al. (Viganò D, Rea N, Pons J A, Perna R, Aguilera D N, Miralles J A 2013 Mon. Not. R. Astron. Soc. 434 123), because they first proposed the up-dated neutron star magneto-thermal evolution model, which can successfully explain the X-ray radiation and cooling mechanism of young pulsars including magnetars and high-magnetic field pulsars. Objectively speaking, as to the decay of toroidal magnetic fields, there are some differences between our theoretical calculations of magnetic energy release rates and the actual situation of magnetic field decay in magnetars, this is because the estimate of initial dipolar magnetic field, true age and the thickness of inner crust of a magnetar are somewhat uncertain. In addition, due to the interstellar-medium’s absorptions to soft X-ray and the uncertainties of distance estimations, the observed soft X-ray luminosities of magnetars have certain deviations. With the continuous improvement of observation, equipment and methods, as well as the in-depth development of theoretical research, our model will be further improved, and the theoretical results are better accordant with the high-energy observation of magnetars.We also discuss other possible anisotropy origins of soft X-ray fluxes of magnetars, such as the formation of magnetic spots and thermoplastic flow wave heating in the polar cap. Although anisotropic heating mechanisms are different from Ohmic decay, all of them require that there exist strong toroidal magnetic fields inside a magnetar. However, the anisotropic heating mechanisms require higher toroidal multipole fields inside a magnetar (such as magnetic octupole field) and are related to complex Hall drift: these may be our research subjects in the future.

Silicon carbide (SiC), as a representative of the third-generation semiconductor materials, is widely used in some fields which may suffer strong radiation such as in the cases of military affairs, aerospace and reactor. SiC possesses the superior radiation-resistance characteristic. However, SiC under the proton irradiation generate a lot of defects, resulting in degradation of device performance and even complete loss of its function. Therefore, the study on the irradiation damage to SiC under proton irradiation possesses important significance. A large number of studies have shown that for most of electronic devices and different types of incident particles, the degradation of device performance caused by displacement damage is linearly dependent on non-ionizing energy loss (NIEL), so the displacement damage can be evaluated by NIEL. In this work, the Monte Carlo software Geant4 is used to simulate the relationship between NIEL and proton energy, and the variation of NIEL with the depth of the material and the contribution of different types of primary recoil atoms to the total NIEL are also studied. The NIEL simulation results show that the NIEL in SiC material is less than that in Si and Ga semiconductor material under the same proton irradiation, proving that the stability and the radiation-resistance of SiC are stronger. The simulation results of NIEL at different depths show that the most serious damage regions of the material under different energy protons are diverse. Under the irradiation of low energy proton, the most serious region of the displacement damage occurs at the end of the proton range. With the increase of proton energy, the worst damage region of material will gradually move from the end of the proton range to the surface of SiC material. According to the contribution of different types of primary recoil atoms to the total NIEL, when the energy of the incident proton is low, the displacement damage of the proton in the SiC is mainly caused by 28Si and 12C, and the damage caused by 28Si is obviously higher than that by 12C. As the energy of proton increases, the 28Si and 12C are still the main causes of Bragg peak of the NIEL at the end of the proton range, but the number of ions generated by nuclear reactions increases accordingly, and the displacement damage caused by these ions increases in the shallow area of SiC, leading the surface of the material to be the worst damaged region. The combination of the two factors caused the most serious damage region moves from the end of the proton range to the surface of the material with the increase of proton energy. The results of this study are useful for the application of SiC devices to irradiation environment.

Radiation effects of the floating gate read-only-memory (FG ROM) and the static random access memory (SRAM) have been evaluated using the 14 MeV neutron and 31.9MeV proton beams and Co-60 γ-rays. The neutron fluence, when the first error occurs in the FG ROMs, is at least 5 orders of magnitude higher than that in the SRAMs, and the proton fluence, 4 orders of magnitude higher. The total dose threshold for Co-60 γ-ray irradiation is about 104 rad (Si) for both memories. The difference and similarity are attributed to the structure of the memory cells and the mechanism of radiation effects. It is concluded that the FG ROMs are more reliable as semiconductor memories for storing data than the SRAMs, when they are used in the satellites or space crafts exposed to high energy particle radiation.

Silicon devices are extensively used in space and other radiation-rich environments. They must withstand radiation damage processes that occur over wide range of time and length. Ion implantation technique, one of the most important process in the fabrication of integrated circuits, can also create the displacement damage in silicon lattice. Exposure of silicon wafer or silicon device to radiation causes the creations of variety of defects and has adverse effects on the electrical properties of devices. Although phenomenological studies on the radiation effects in silicon have been carried out in the past decades, the features of multi-scale of displacement damage make it difficult to characterize the defect production and evolution experimentally or theoretically. Recently, the silicon device with ultra-low leakage current was shown to be very sensitive to the permanent displacement damage induced by single particles, called single particle displacement damage (SPDD) event. To the best of our knowledge, the investigation of single particle displacement damage (SPDD) event in silicon device by the coupling molecular dynamics (MD) and kinetic Monte Carlo (KMC) techniques has not yet been reported so far. In this paper, MD simulations are combined with KMC simulations to investigate the formation and evolution of SPDD event in silicon. In MD simulations, Tersoff potential is used to describe the Si-Si atomic interactions. The potential smoothly joins to Ziegler-Biersack-Littmark potential that describes the energetic short range interactions well. All atoms in the MD cell are allowed to evolve 0.205 ns to track the damage production and short-term evolution. A multi-phase simulations are performed to improve the simulation efficiency. Then the nearest neighbor criterion is employed to identify the configurations and spatial distributions of interstitials and vacancies, which are used as input in KMC simulations to study the thermal diffusion and interactions of those defects in the time interval from 0.205 ns to 1000 s. The results show that no defects are missing when transferring from MD to KMC simulation and the whole damage obtained in MD simulations is reproduced in KMC simulations. Since the production and evolution of defects are simulated, the SPDD current could be calculated based on Shockley-Read-Hall theory. We derive the formula to calculate the SPDD current and its annealing factor related to interstitials and vacancies in the depletion region. The calculated annealing factors of defects are compared with the annealing factors of SPDD currents and also with the experimental results. The results show that an annealing factor of defects has the same value as the annealing factor of an SPDD current when only one type of defect is considered in the calculations, while there are some differences between these two annealing factors when two and more types of defects are considered. The annealing factors of defects can be used to represent the annealing behaviors of SPDD currents since the divergences between these two annealing factors are not significant. Finally, SPDD current annealing factor based MD simulation results obtained with Tersoff potential are compared with the results in our previous study in which the Stillinger-Weber potential is used, and also compared with experimental results. The comparisons show that the simulation results with considering both Stillinger- Weber potential and Tersoff potential are in good agreement with experimental results. Compared with the calculated results with considering the Tersoff potential, the results with considering the Stillinger-Weber potential are closer to experimental results.

We investigate the structural transformations of water at the water/quartz interface under shock compression in ranges from 0.5 to 2 GPa and from 335 to 375 K by techniques of a gas-gun and light transmission tests. The results show that the structural transformation of water occurs in the region of liquid phase, which starts from water/quartz interface at high pressures and temperatures. The transformation rate is related to the property of quartz interface. This structural evolution indicates that a lager number of water molecules undergone transitions in equilibrium behavior. The kinetic process of liquid water structure can be divided into four stages while the structure continues growing to saturation. This new mechanism of structural transformation has immediate implications for water structure transformation in diverse natural environments.

We combine the flyer-impact experiment and improve the finite difference method to solve whether the shear viscosity coefficient of shock iron is more reliable. We find that the numerical simulated profile agrees well with the measured one, from which the determined effective shear viscosity coefficients of shocked iron are 3000 ? 100 Pa?s and 4000 ? 100 Pa?s, respectively, at 103 GPa and 159 GPa. These values are more than 2000 ? 300 Pa?s of Li Y L et al.[Chin. Phys. Lett. 26 (2009) 038301] Our values are more reasonable because they are obtained from a comprehensive simulation for the full-shocked perturbation evolving process.

This paper reports the temperature relaxation process at melting iron/sapphire interface under shock compression, and interpretes the phenomenon basing on transformation kinetics and heat conduction equation. Analysis shows that if iron keeps melting, the history of interface temperature is affected by the melting speed. The interface temperature undergoes a slow cooling process when the melting speed of iron is finite, which is different from the result of previous researches. Simulation signal can be made accord ant with the experimental signal by adjusting some parameters. It was found that the melting temperature and melting speed of iron at high pressure can be dctermined by researching the relaxation process. So, this paper shows a new theoretical method and its experimental verification.

In this paper, we study the crystallization of water due to fused quartz effect under shock compression by a gas gun and light transmission tests. The experimental results indicate that at 1.28 GPa water rapid crystallizes when the water has come into direct contact with the quartz glass. On the contrary, freezing cannot occur within 2 s, demonstrating that the observed phenomenon of the liquid-solid phase transition of water can be promoted by the fused quartz. The dynamics of the phase transition is also discussed in this paper.

Optical transmission of quartz glass is measured during loading and unloading process，and the stress was kept below their Hugoniot elastic limit. The results show that the quartz glass maintains good transparency for more than 15 μs under loading processes of 18 GPa，then it starts to lose its transparency about 07 μs after unloading，with 30% decrease of transmittance. This phenomenon，which reflects the growth and evolution of failure induced by unloading process in quartz glass，has been explained reasonably by the growth of spherical particles and the scattering model. The results are different from the explanation of liquid-solid phase transition given in literature［J. Chem. Phys. 2004，121 9050］. This paper is significant for studying the transparency of other transparent material.

To solve the method of measuring the viscosity of related substance at high pressures and high temperatures, Sakharov has proposed an experimental method of small disturbance in shock wave. However, the quantitative relation between the disturbance amplitude damping and viscosity in Sakharov flow field has not been given by theory. In this paper, the propagation of complex flow in Al, the development of relative disturbance amplitude on sinusoidal shock front, and the effect of viscosity on it are studied, and the relation between the relative distance of zero-point on the disturbance amplitude damping curve and viscosity is given. Compared with Zaidel’s uniform flow model and Millers’ nonuniform flow model, our Sakharov flow is close to real experiment. From our numerical analysis method, Sakharov small disturbance experiment can give a credible viscosity coefficient. We analyze the experimental data of Mineev again, and find the effective viscosity coefficient of Al at shock pressure 31 GPa and strain rate 2×106 s-1 should be modified by 1100 Pa·s, which is half of the former analytic result.

A kind of test method of total dose effects (TDE) is presented for very large scale integrated circuits (VLSI). The consumption current of devices is measured while function parameters of devices (or circuits) are measured. Then the relation between data errors and consumption current can be analyzed and mechanism of TDE in VLSI can be proposed. Experimental results of 60Co γ TDEs are given for SRAMs, EEPROMs, FLASH ROMs and a kind of CPU.

The experiments of ionizing radiation were performed on floating gate ROM device s by using 60Coγrays. The experimental aim was to examine the radi ation response at various dose rates. According to the extrapolation technique and the failu re criteria we defined,the parameter failure and function failure of devices vs. dose rate were studied. Finally, based on the function of failure timevs. doserate, the failure time of floating gate ROM device in space radiation environm ent was predicted.

In this paper the characteristics of isothermal and isochronal annealing for post-radiated MOS transistor were studied. The results show that 100℃ isothermal a nnealing is the most effective treatment, while the time of isochronal annealing is the shortest. Secondly, the recovery of threshold voltage under the +5V bias is the fastest and biggest, compared to that under 0V and float bias. These predictied results by using isochronal annealing data were compared with the ex periment curve obtained from isothermal annealing, and the agreement is good.

In this paper, we discuss the special structures of dislocations in h.c.p. metals. Two sets of dislocations that lay on two parallel non-basal slip planes will change their shape soasto become zigzag and form regular dislocation structures if the spacing of the slip planes is smaller than one quarter of the distance between the dislocations in the dislocation array. Under TEM observation, these structures appear to be regular dislocation networks that present double lines in one direction. Two of these dislocation networks in α-Ti were observed and others were shoAved schematically.

The microstructure of the single core and multifilamentary Nb/Nb3Sn composite materials has been observed using a 1000 kV HVEM. Two types of moire patterns, formed by overlapping Nb3Sn/Nb3Sn and Nb/Nb3Sn crystals respectively, have been found.