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A fully coherent free electron laser (FEL) seeded with a higher-order harmonic (HH) pulse from high-order harmonic generation (HHG) is successfully operated for a sufficiently prolonged time in pilot user experiments by using a timing drift feedback. For HHG-seeded FELs, the seeding laser pulses have to be synchronized with electron bunches. Despite seeded FELs being non-chaotic light sources in principle, external laser-seeded FELs are often unstable in practice because of a timing jitter and a drift between the seeding laser pulses and the accelerated electron bunches. Accordingly, we constructed a relative arrival-timing monitor based on non-invasive electro-optic sampling (EOS). The EOS monitor made uninterrupted shot-to-shot monitoring possible even during the seeded FEL operation. The EOS system was then used for arrival-timing feedback with an adjustability of 100 fs for continual operation of the HHG-seeded FEL. Using the EOS-based beam drift controlling system, the HHG-seeded FEL was operated over half a day with an effective hit rate of 20%–30%. The output pulse energy was $20~{\rm\mu}\text{J}$ at the 61.2 nm wavelength. Towards seeded FELs in the water window region, we investigated our upgrade plan to seed high-power FELs with HH photon energy of 30–100 eV and lase at shorter wavelengths of up to 2 nm through high-gain harmonic generation (HGHG) at the energy-upgraded SPring-8 Compact SASE Source (SCSS) accelerator. We studied a benefit as well as the feasibility of the next HHG-seeded FEL machine with single-stage HGHG with tunability of a lasing wavelength.
We present a rare case of tracheostomy for removal of laryngeal foreign bodies consisting of three connected fish vertebral bones in a 15-month-old girl. Recent endoscopic techniques have made it possible to extract nearly all tracheobronchial foreign bodies with rigid bronchoscopes. However, the three connected foreign bodies in this report could not be extracted entirely by single endoscopy because the glottis as an exit was narrow due to severe oedema. Accordingly, tracheostomy was required to assist ventilation, prevent prolonged post-operative endotracheal intubation, remove the secondary tracheal foreign bodies and to provide a conduit for the introduction of a bronchoscope.
This suggests that tracheostomy should be considered to avoid the potential dangers of severe laryngeal oedema and to secure the route for removal of foreign bodies from the trachea when treating patients with multiple laryngeal foreign bodies and laryngeal oedema.
High-resolution K-shell spectra of a plasma created by superintense laser irradiation of micron-sized Ar clusters have been measured with an intensity above 1019 W/cm2 and a pulse duration of 30 fs. The total photon flux of 2 × 108 photons/pulse was achieved for Heα1 resonant line of Ar (λ = 3.9491 Å, 3.14 keV). In parallel with X-ray measurements, energy distributions of emitted ions have been measured. The multiply charged ions with kinetic energies up to 800 keV were observed. It is found that hot electrons produced by high contrast laser pulses allow the isochoric heating of clusters and shift the ion balance toward the higher charge states, which enhances both the X-ray line yield of the He-like argon ion and the ion kinetic energy.
The effect of thin Ti/PbZr0.4Ti0.6O3 seed layers on the properties of PbZr0.4Ti0.6O3 (PZT) capacitors has been investigated. The seed layer is based on a bi-layer of thin Ti and thin PZT with a total thickness ranging from 10 to 25 nm, which was deposited on Ir/Pt or Ir/IrO2/Pt by sputtering. After crystallization of the seed layers the main 130-nm-thick PZT film was deposited and crystallized. As a result, a highly preferred (111)-orientation of the PZT was obtained on a 10-nm-thick seed layer, where the peak intensity ratios of (111)/{100} and (111)/{110} are about 100 and 20, respectively. The 10-nm-thick seed forms a pyrochlore phase with a very smooth surface, where the formation of the pyrochlore phase is attributed to Pb diffusion, resulting in a Pb deficient stoichiometry. The seed layer transformed to the perovskite phase during the main PZT crystallization. It is shown that an IrO2 layer beneath the Pt can prevent Pt layer degradation related to the volume expansion due to the oxidation of Ir during the main PZT crystallization. Capacitors with the 10-nm-thick seed layer fabricated on the Ir/Pt and Ir/IrO2/Pt substrates showed typical 2 Pr values of 44.0 μC/cm2 and 41.2 μC/cm2, respectively. The voltage found for 90%-polarization saturation is about 3.0 V, and the capacitors are fatigue-free at least up to 1010 switching cycles.
The behaviour of dioxin in several arc furnaces was studied in detail in relation with the specifications for various types of organic and inorganic gas. After a pilot plant study has been carried out to know the effect of secondary combustion and rapid cooling on the reduction of dioxin in the arc fumace, ways to lower dioxin below regulation levels were proposed. To understand the reactions, laboratory studies and thermodynamic calculations have been done.
For high density FeRAM devices small cell sizes are essential. The combination of the capacitor on plug (COP) structure with the Chain FeRAM™ cell design is used to develop a 32Mb FeRAM. Based on a 0.2 μm standard CMOS process a silicide capped polysilicon plug is used to contact the bottom electrode of the ferroelectric capacitor to the transistor. The barrier contact to the plug is formed by IrO2/Ir and a sputter deposited PZT (40/60) is used as ferroelectric material. The function of SrRuO3 (SRO) layers at the electrode/PZT interfaces is described in more detail. Double sided SRO results in slightly lower coercive voltage and imprint behavior compared to capacitors without SRO. Double sided SRO is essential to achieve excellent fatigue behavior measured up to 1×1011 switching cycles.
Increases in height were reported in children chronically exposed prenatally and postnatally to D2 receptor-blocking drugs. A possible haplotypic association between stature and the DRD2 gene was also reported. In this study, we examined linkage between stature and DRD2 by genotyping a dinucleotide repeat polymorphism in 79 sib-pairs aged 8–17 years. An association between stature and a putative functional polymorphism in the promoter region of the DRD2 gene was examined in the sib-pairs and in 125 unrelated male adults. All the subjects were Japanese. Linkage (p = 0.004, SIBPAL) and an association (p = 0.009, paired t-test, in the sib-pairs; p = 0.006, ANOVA, in the adults) with stature were suggested. These findings indicate that DRD2 is one of the genes that contribute to heritability of stature.
A high-current, low-energy multi-ion beam deposition system has been developed for the fabrication of tailored new materials. This system consists of two ion sources, a dual-sector type mass analyzer and a deceleration system. Several ion species can be extracted successively from the two ion sources by switching the mass analyzer selection. Artificially structured materials, especially having a layered structure, can be grown by the fine control of the growth process of each layer. Ar* ion deceleration characteristics of this ion beam deposition system and preliminary results about the epitaxial growth of Ca film on Si(100) are shown.
Hydrogenated amorphous silicon (a-Si:H) films prepared by electron cyclotron resonance plasma enhanced CVD (ECR PECVD) were investigated electrically and optically. The electrical and optical properties of a-Si:H were strongly dependent on magnet coil current, microwave power, and substrate temperature. A high deposition rate of a-Si:H up to 150 nm/min was realized by this technology. The photoconductive characteristics prepared at 300°C are comparable to those obtained by glow discharge PECVD (GD PECVD).
Doping effects of metal ions in chalcogenide glass films were studied. Doped impurities were found to act as donor or acceptor centers, when impurity ions were introduced in chalcogenide glass films below the glass transition temperature. Rectifying effects were realized in chalcogenide glass films doped with Al, Cd and Mg, so it is certain that the p-n junction was formed by the impurity doping. The tunneling of electrons through gap states, however, appeared to increase the reverse current of heavily doped diodes, so that large rectifying effects were not attained. A high density of defect states especially in the surface region would be responsible for low temperature diffusion of metal ions.
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