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The article discusses a recently developed nonperturbative quantum theory, which explains the phonon-assisted photon absorption of conduction band electron in intense laser.

The control efficacy of tea polyphenol ( TP) in combination with tea saponin ( TS) against nectarine grey mould decay caused by Botrytis cinerea and the underlying mechanism were investigated. The in vitro experiments showed that both TP and TS inhibited the mycelial growth in a dose-dependent manner, and their combinations exhibited synergistic antifungal interactions with the synergistic ratios ( SR) exceeding 1·5. The in vivo experiments showed that disease incidence and lesion diameter of grey mould of inoculated fruit were significantly lowered after being treated with the combination of TP and TS; furthermore, the activities of phenylalanine ammonia-lyase ( PAL), peroxidase ( POD), polyphenol oxidase ( PPO), chitinase and β-1,3-glucanase of inoculated fruit as well as the contents of total phenolic and lignin were significantly induced, the respiration rate of inoculated fruit was significantly decreased and therefore the quality decrease was accordingly retarded. These results revealed that TP in combination with TS could control grey mould of inoculated nectarines and their mechanism of action might be attributed to their active components, the induction of defensive system and the regulation of respiration. Significance and Impact of the Study This study demonstrates that the combination of TP and TS has exhibited synergistic antifungal interactions against Botrytis cinerea, and it suggests that their combination may be useful and effective agents for the control of nectarine grey mould decay. Such natural products therefore represent a promising alternative to synthetic fungicides in the control of nectarine postharvest diseases. [ABSTRACT FROM AUTHOR]

Abstract: The effect of Ge addition on the microstructure, transformation temperatures and mechanical properties of (Ni56.5Fe17Ga26.5)100−x Ge x ferromagnetic shape memory alloys was investigated. With the increase of Ge content in these alloys the martensitic transformation temperatures decrease almost linearly from higher than 100°C down to −70°C or even lower that is attributed to the change of the electron concentrations of the Ni–Fe–Ga(Ge) alloys. The addition of Ge also significantly enhances the compression strength and the ductility of the alloys. The determined relationships between transformation temperatures and the mechanical properties and the Ge content will be useful for designing a suitable Ni–Fe–Ga(Ge) alloy device with a required martensitic transformation temperature and optimized mechanical property. [Copyright &y& Elsevier]

A new nonlinear filter is proposed for attenuating impulsive noise while preserving image details. The filter truncates the grey value of a pixel to the maximal or minimal value of its enclosed surrounding band. Impulsive noise inside the band is thus attenuated while image details are preserved as long as they stretch to the band. The recursive form of the proposed filter leads to a simple architecture for fast implementation. Theoretical analysis and experimental results demonstrate the effectiveness of this new filter for both noise attenuation and detail preservation. For moderately contaminated images, as shown in the experiments, the proposed filter outperforms the standard median filter, the centre-weighted median filter and the unidirectional multistage median filter in terms of mean absolute error and filtering speed. [ABSTRACT FROM AUTHOR]

Abstract: SiO2 films were deposited on K9 substrate by the electron-beam evaporation method. The influence of oxygen-plasma posttreatment on the properties of SiO2 films was investigated. After oxygen-plasma treatment, it was found that the microdefect density of films reduced. We deduced that the absorption of films also reduced. The treated sample exhibited higher LIDT value compared with the as-deposited sample. However, this study is the preliminary work and optimization by this method will be discussed in our future work. [Copyright &y& Elsevier]

Abstract: Monolayer zirconia physical vapor deposition (PVD) and sol–gel films on K9 glass substrates were prepared by electron beam evaporation and spin coating methods, respectively. The laser-induced damage threshold (LIDT) of each film was measured. Properties of the films were analyzed using Stanford photo-thermal solutions (SPTS), ellipsometry, atomic force microscopy (AFM) and optical microscopy to study the damage mechanism of films under laser irradiation. The experimental results showed that, compared with the monolayer zirconia sol–gel film, the monolayer zirconia PVD film had larger absorption and smaller porous ratio, and that it had smaller LIDT. The different damage morphologies of films were influenced by their different absorption and microstructure characteristics. The zirconia sol–gel film is more suitable for applications involving high-power lasers. [Copyright &y& Elsevier]

Abstract: Sol–gel single-layer silica acid and base thin films on K9 glass substrates were prepared with the dip-coating method from acid and base catalyzed silica sols, respectively. Laser-induced damage threshold (LIDT) of each film was measured. Properties of the films were analyzed using Stanford photo-thermal solutions (SPTS), ellipsometry, atomic force microscopy (AFM) and optical microscopy to study the damage mechanism of the films under laser irradiation. The experimental results showed that compared with the silica base film, the silica acid film had larger absorption and smaller porous ratio, and it had smaller LIDT. The different damage morphologies of films were influenced by their different absorption and microstructure characteristics. The silica base film is more suitable for applications involving high power lasers. [Copyright &y& Elsevier]

In this work, the effects of laser irradiation on fused silica at 355 nm are investigated by using transient absorption spectroscopy and luminescence spectroscopy. Our result shows that no transient absorption or luminescence in the spectra range from 400 nm to 600 nm is observed when laser energy density is below the damage threshold. When the laser energy density reaches the threshold, an initial damage site will be created. After subsequent laser pulses irradiation, the damage size grows. At the same time, the intensity of the transient absorption and luminescence spectra at the damage site also raises remarkably with the laser pulse number increasing. The absorption band from 420 nm to 520 nm is probably related to the absorption of impurity such as metal ion of iron, cerium and copper. Laser modified fused silica exhibits intense broad luminescence bands due to oxygen-deficiency centers at 444 nm and 580 nm. [ABSTRACT FROM AUTHOR]

Abstract: Monolayer ZrO2 sol–gel and physical vapor deposition (PVD) films were prepared by spin method and electron beam evaporation method, respectively. Monolayer sol–gel SiO2 films were prepared with the dip-coating method from acid and base catalyzed SiO2 sols, respectively. Some of the SiO2 base films were subsequently treated in saturated ammonia gas for 20h. The laser induced damage threshold (LIDT) of each film was measured. Properties of the films were analyzed by using Stanford photo-thermal solutions (SPTSs), ellipsometer, atomic force microscopy (AFM) and optical microscopy. The experimental results showed that porous ratio is an essential factor to decide the LIDT for sol–gel films, which benefits the pressure exerted on the film or substrate by the moving particle to dissipate. The films with lower thermal absorption and higher porous ratio have higher LIDT. [Copyright &y& Elsevier]

Abstract: UV laser irradiation induced structural modification in amorphous silica was characterized using Fourier transform infrared and X-ray induced photoelectron spectroscopy. Laser irradiation experiment was conducted using a 3ω, 355nm beam from a pulsed Nd-YAG laser with pulse length of 6.8ns and laser repetition rate of 1Hz at ambient conditions. The examined laser fluence was controlled at a relatively low level, ranging from 0 to 4J/cm2. The IR spectra revealed that the vibration frequency of the rocking mode of Sih name="sbnd" />Si covalent bond shifted to lower wave number, while the bending mode and asymmetric stretching mode of Sih name="sbnd" />Si covalent bond shifted to higher frequency. This result suggested that the length of Sih name="sbnd" />Si covalent bond was decreased, the bond angle was increased and the irradiation modified material was densified after irradiation. The high resolution XPS spectra of Si 2p and O 1s illustrated the chemical shift of silicon and oxygen ions after irradiation. The XPS chemical shift of the Si 2p peak about 1.1eV revealed the existence of low valence silicon ions Si3+ species in silica glass after irradiation. The chemical shift of the O 1s peak about 0.9eV illustrated the emergence of non-bridging oxygen ions during laser irradiation. The deconvoluted peak area and FWHM value of low valence silicon ions and non-bridging oxygen ions all exhibited exponentially growth as the linearly elevation of laser fluence. UV laser-induced photolysis of Sit bond was suggested to be responsible for the formation and increase of low valence silicon ions and non-bridging oxygen ions. These FT-IR and XPS data revealed that short range structural modifications were important structure alterations in silica glass before the emergence of distinct and large size damage crater. [Copyright &y& Elsevier]

Abstract: Metal inclusions play critical roles in laser-induced damage for large fused silica optics. Here, the spatial distribution of sodium, aluminum, iron and copper in as-prepared samples is analyzed by synchrotron based X-ray fluorescence spectrometry microprobe system at the BL15U1 beam line at the Shanghai Synchrotron Radiation Facility. The as-prepared fused silica samples are induced by 355nm laser pulses with no, or low, or high fluences. The spatial resolution of the obtained elemental maps is up to 50μm. Analysis of the elemental maps indicates that the distribution of metals has a close association with the laser fluence and pulses. The normalized fluorescence signal attenuation for metal inclusions corresponds to the laser fluence. The decrement of metals depends chiefly upon the fluence other than pulses of the incidence laser, which is most pronounced for iron and least for copper. The decrement is evident for high fluence laser irradiation, while the amount is negligible for low fluence laser irradiation. Among the four metals, iron concentration is suggested as the most destructive factor for optics lifetime, especially under high fluence irradiation. The quasi-periodic feature of elemental distribution is partly ascribed to laser intensity modulation induced by Fresnel diffraction. [Copyright &y& Elsevier]

Abstract: Two-layer ZrO2/SiO2 and SiO2/ZrO2 films were deposited on K9 glass substrates by sol–gel dip coating method. X-ray photoelectron spectroscopy (XPS) technique was used to investigate the diffusion of ZrO2/SiO2 and SiO2/ZrO2 films. To explain the difference of diffusion between ZrO2/SiO2 and SiO2/ZrO2 films, porous ratio and surface morphology of monolayer SiO2 and ZrO2 films were analyzed by using ellipsometry and atomic force microscopy (AFM). We found that for the ZrO2/SiO2 films there was a diffusion layer with a certain thickness and the atomic concentrations of Si and Zr changed rapidly; for the SiO2/ZrO2 films, the atomic concentrations of Si and Zr changed relatively slowly, and the ZrO2 layer had diffused through the entire SiO2 layer. The difference of diffusion between ZrO2/SiO2 and SiO2/ZrO2 films was influenced by the microstructure of SiO2 and ZrO2. [Copyright &y& Elsevier]

Abstract: Single-layer optical films, ZrO2, SiO2 and HfO2, were deposited on K9 glass substrates by ion beam sputtering deposit technique in order to study laser-induced damage threshold (LIDT) and damage mechanism. Impurities and defects will result in strong weak absorption coefficient and photothermal signal. Further LIDT is inverse proportional to the absorption coefficient of the films. AFM images of as-deposited films showed a similar roughness of 2–4nm. Among the films, ZrO2 film has a pore structure, which results in the largest weak absorption, photothermal effect and smallest LIDT. HfO2 film has the largest LIDT (22.13J/cm2) due to the smallest number and size of both defects and impurities on the surface. Different films have different damage morphology, which is related to the morphology of defects or impurities in the film before laser irradiation and the interface between films and substrates. In order to enhance LIDT, it is important to prepare high-quality film and passivate the defects in the films. [Copyright &y& Elsevier]

Abstract: Sol–gel (ZrO2/SiO2)12 ZrO2 films were prepared by spin coating method. The reflectivity spectrum of the films was measured with a Lambda 900 spectrometer. In order to investigate laser-induced damage threshold (LIDT) characteristic of highly reflective films, one-layer ZrO2 and SiO2 films, two-layer ZrO2/SiO2 and SiO2/ZrO2 films were also prepared by spin coating method. LIDT of each film was measured. Damage morphology after laser irradiation was characterized by optical microscopy (Nikon E600K). The experimental results showed that the reflectivity of (ZrO2/SiO2)12 ZrO2 film at 1064nm and 355nm wavelength is 99.7%. The LIDT results decreases as the number of layer of films increases. All the films have similar damage morphology. The experimental results are explained by the different temperature profiles of the films. [Copyright &y& Elsevier]