The influence of the microstructure evolution on the surface morphology in the annealing process of helium-implanted spinel

Single-crystalline spinel (MgAl2O4) specimens were implanted with helium ions of 100 keV at three successively increasing fluences of (0.5, 2.0 and 8.0) x 10(16) ions/cm(2) at room temperature. The specimens were subsequently annealed in vacuum at different temperatures ranging from 500 to 1100 degrees C. Different techniques, including Fourier transformed infrared spectroscopy (FTIR), thermal desorption spectrometry (TDS), atomic force microscopy (AFM) and scanning electron microscopy (SEM) were used to investigate the specimens, It was found that the absorbance peak in the FTIR due to the stretching vibration of the Al-O bond shifts to smaller wave numbers with increasing fluence, shifting back to larger wave numbers with an increase of annealing temperature. The absorbance peak shift has a linear relationship with the fluence increase in the as-implanted state, while it does not have a linear relationship with the fluence increase after the annealing process. Surface deformation occurred in the specimens implanted with fluences of 2.0 and 8.0 x 10(16) ions/cm(2) in the annealing process. The phenomena described above can be attributed to differences in defect formation in the specimens. (C) 2008 Elsevier B.V. All rights reserved.

Annealing effects in silicon implanted with helium

Silicon samples were implanted with helium and analyzed by atomic force microscopy (AFM) and Raman spectroscopy before and after annealing in the range of 523-1273 K. After annealing at 523 K, the amorphous area induced by He-ion implantation at room temperature was partially recovered and grain sizes became larger. The surface morphology was analyzed through AFM measurements and it was observed that root mean square of the surface roughness alters upwards and then downwards with annealing temperature. (C) 2008 Elsevier B.V. All rights reserved.

Effects of annealing on the photoluminescence of He ion implanted sapphire after 230-MeV Pb ion irradiation

Single crystal sapphire (Al2O3) samples implanted with 110 keV He and irradiated at 320 K by Pb-208(27), ions with energy of 1.1 MeV/u to the fluences ranging from 1 X 10(12) to 5 X 10(14) ion/cm(2) and subsequently annealed at 600, 900 and 1100 K. The obtained PL spectra showed that emission peaks centred at 375, 390, 413, and 450 nm appeared in irradiated samples. The peak of 390 ran became very intense after 600 K annealing. The peak of 390 nm weakened and 510 nm peak started to build up at 900 K annealing, the peak of 390 nm vanished and 510 nm peak increased with the annealing temperature rising to 1100 K. Infrared spectra showed a broadening of the absorption band between 460 cm(-1), and 510 cm(-1) indicating strongly damaged regions being formed in the Al2O3 samples and position shift of the absorption band at 1000-1300 cm(-1) towards higher wavenumber after Pb irradiation.

Temperature annealing of tracks induced by ion irradiation of graphite

Highly oriented pyrolytic graphite (HOPG) samples were irradiated by Xe ions of initial kinetic energy of 3 MeV/u. The irradiations were performed at temperatures of 500 and 800 K. Scanning tunneling microscopy (STM) images show that the tracks occasionally have elongated structures under high-temperature irradiation. The track creation yield at 800 K is by three orders of magnitude smaller compared to that obtained during room-temperature irradiation. STM and Raman spectra show that amorphization occurs in graphite samples irradiated at 500 K to higher fluences, but not at 800 K. The obtained experimental results clearly reveal that the irradiation under high temperature causes track annealing.

聚乙二醇模拟干旱对甜高粱幼苗丙二醛、脯氨酸含量的影响；Effects of Drought Stress Simulated by PEG on Malonaldehyde and Proline Contents of Sweet Sorghum Seedlings

以甜高粱品种KFJT-CK及经过碳离子辐照选育出的早熟突变株KFJT-1为材料,用浓度分别为5%,10%和15%的聚乙二醇(PEG)6000模拟干旱对其进行胁迫处理,测定丙二醛(MDA)及脯氨酸(Pro)的含量。随着胁迫时间的延长和胁迫程度的增加,MDA含量持续升高;Pro含量在5%和10%PEG胁迫下持续升高,在15%PEG胁迫下先升高后降低。表明碳离子辐照可能使甜高粱膜脂过氧化特性发生改变,影响Pro的表达。为进一步研究碳离子束辐照对甜高粱的耐旱生理提供一定的基础,并为下一步的育种工作提供有用的参考。

The effects of the annealing time on helium implantation in Si

The modifications induced in silicon samples by helium implantation before and after isothermal annealing at 673 K have been investigated. The surface morphology has been detected by atomic force microscopy. A hillock structure is observed on the sample surface before and after annealing for 5-10 min. Surface blister formation is observed with an increasing annealing time. The variation of crystal damage with annealing time has been investigated by Rutherford backscattering/channeling. The intensity of the damage peak first increases with annealing time, reaches maximum at an annealing time of 60 min and then decreases. Helium-induced bubbles and residual defects have been observed by transmission electron microscopy, which shows that dislocations are close to the bubbles. (C) 2010 Elsevier B.V. All rights reserved.

The annealing behavior of Cu nanoparticles in Ar-ion implanted spinel

Magnesium aluminate spinel crystals (MgAl2O4 (1 1 0)) deposited with 30 nm Cu film on surface were implanted with 110 key Ar-ions to a fluence of 1.0 x 10(17) ions/cm(2) at 350 degrees C, and then annealed in vacuum condition at the temperature of 500, 600, 700, 800 and 900 degrees C for 1 h, respectively. Ultraviolet-visible spectrometry (UV-VIS), scanning electron microscopy (SEM), Rutherford backscattering (RBS) and transmission electron microscopy (TEM) were adopted to analyze the specimens. After implantation, the appearance of surface plasmon resonance (SPR) absorbance peak in the UV-VIS spectrum indicated the formation of Cu nanoparticles, and the TEM results for 500 degrees C also confirmed the formation of Cu nanoparticles at near-surface region. In annealing process, The SPR absorbance intensity increased at 500 and 700 degrees C, decreased with a blue shift of the peak position at 600 and 800 degrees C, and the peak disappeared at 900 degrees C. The SPR absorbance intensity evolution with temperature was discussed combined with other measurement results (RBS, SEM and TEM). (C) 2010 Elsevier B.V. All rights reserved.

Enhanced photoluminescence of Ar+ implanted sapphire before and after annealing

In this paper, we studied the changes in the photoluminescence spectra of the Ar+ ion implanted monocrystalline sapphire annealed at different atmospheres and different temperatures. Single crystals of sapphire (Al2O3) with the (1 0 (1) over bar 0) (m-samples) orientation were implanted at 623 K with 110 keV Ar+ ions to a fluence of 9.5 x 10(16) ions/cm(2). Photoluminescence measurement of the as-implanted sample shows a new emission band at 506 nm, which is attributed to the production of interstitial Al atoms. The intensity of emission band at 506 nm first increased then decreased with increase in annealing temperature. For the same annealing temperature, the intensity of PL peak at 506 nm of the sample annealed in air was higher than the sample annealed in vacuum. The experimental results show that the intensity of the PL peak at 506 nm of Ar-implanted sapphire can be enhanced by subsequent annealing with an enhancement of nearly 20 times. The influence of thermal annealing of the Ar-implanted samples on the new 506 nm emission band was discussed. (C) 2009 Elsevier B.V. All rights reserved.

Effect of substrate and annealing on the structural and optical properties of ZnO:Al films

ZnO:Al thin films with c-axis preferred orientation were deposited on glass and Si substrates using RF magnetron sputtering technique. The effect of substrate on the structural and optical properties of ZnO:Al films were investigated. The results showed a strong blue peak from glass-substrate ZnO:Al film whose intensity became weak when deposited on Si substrate. However, the full width at half maxima (FWHM) of the Si-substrate ZnO:Al (0 0 2) peaks decreased evidently and the grain size increased. Finally, we discussed the influence of annealing temperature on the structural and optical properties of Si-substrate ZnO:Al films. After annealing, the crystal quality of Si-substrate ZnO:Al thin films was markedly improved and the intensity of blue peak (similar to 445 nm) increased noticeably. This observation may indicate that the visible emission properties of the ZnO:Al films are dependent more on the film crystallinity than on the film stoichiometry. Crown Copyright (C) 2009 Published by Elsevier Ltd. All rights reserved.

Controls on suppression of methane flux from a peat bog subjected to simulated acid rain sulfate deposition

The effect of acid rain SO42− deposition on peatland CH4 emissions was examined by manipulating SO42− inputs to a pristine raised peat bog in northern Scotland. Weekly pulses of dissolved Na2SO4 were applied to the bog over two years in doses of 25, 50, and 100 kg S ha−1 yr−1, reflecting the range of pollutant S deposition loads experienced in acid rain-impacted regions of the world. CH4 fluxes were measured at regular intervals using a static chamber/gas chromatographic flame ionization detector method. Total emissions of CH4 were reduced by between 21 and 42% relative to controls, although no significant differences were observed between treatments. Estimated total annual fluxes during the second year of the experiment were 16.6 g m−2 from the controls and (in order of increasing SO42− dose size) 10.7, 13.2, and 9.8 g m−2 from the three SO42− treatments, respectively. The relative extent of CH4 flux suppression varied with changes in both peat temperature and peat water table with the largest suppression during cool periods and episodes of falling water table. Our findings suggest that low doses of SO42− at deposition rates commonly experienced in areas impacted by acid rain, may significantly affect CH4 emissions from wetlands in affected areas. We propose that SO42− from acid rain can stimulate sulfate-reducing bacteria into a population capable of outcompeting methanogens for substrates. We further propose that this microbially mediated interaction may have a significant current and future effect on the contribution of northern peatlands to the global methane budget.

Simulated morphological landscape of polymer single crystals by phase-field model

The novel phase field model with the "polymer characteristic" was established based on a nonconserved spatiotemporal Ginzburg-Landau equation (TDGL model A). Especially, we relate the diffusion equation with the crystal growth faces of polymer single crystals. Namely, the diffusion equations are discretized according to the diffusion coefficient of every lattice site in various crystal growth faces and the shape of lattice is selected based on the real proportion of the unit cell dimensions.

The dewetting dynamics of the polymer thin film by solvent annealing

The slippage effect of the polymer chains is investigated in the dewetting process of the polymer solution film. The solvent-induced dewetting is used in our experiments to study the dynamics of hole growth in the dewetting process of the polymer solution film. Our results show that in the case of the low molecular weight polystyrene (PS) film, the slippage effect of the polymer chains is not displayed and the radius of the holes is R similar to exp(t/tau); in the case of the higher molecular weight PS film, the slippage effect of the polymer chain is not valid in the case of the thin film and that is valid in the case of the thick film, and the dynamic process of hole growth divides into three stages (R similar to t, and then R similar to t(x) (2/3 < x < 1), finally, R similar to t). Besides, the solvent and substrate properties also influence the dewetting dynamics of the polymer solution film.