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We have developed a new laser ablation type cluster source named `spatiotemporal confined cluster source' (SCCS), which gives well-defined thermo-dynamical conditions for cluster growth with narrow size dispersion. A laser-induced shock is controlled to produce a definite mixed gas layer of the silicon vapor and helium gas, which is locally confined in a sub millimeter space, and conserved densely for a time of 160 μs. The generated silicon clusters, which are ionized by an ArF excimer laser for mass analysis without dissociation, show narrow size dispersion with characteristically higher abundance of stable Si 23 H x (46%), Si 19 H x (14%), and Si 21 H x (12%) clusters.

The dynamical process of pulsed laser ablation is investigated by means of Monte Carlo simulations in order to develop a new cluster source. The interaction between the ablated Cu vapor plume and the He ambient gas induces strong shock compression of the gas by which the gas density is one order of magnitude increased and forms a stable gas layer mixed with the plume at the contact front. It is found that even with the target-wall distance as short as about 80 μm, a mixed layer more than 10 μm in thickness can be formed at about 15 μm away from the source wall. This layer can be locally-confined for a considerable long time of hundreds of ns. Frequent collisions occur among the atoms of vapor and gas within the confined layer which induce effective cluster aggregation. The thermodynamic state of this region is well defined, so that the mono-dispersed growth condition might form cluster beam with well-defined internal freedom.

We have constructed a new massive ion beam system for the studies on well-defined microclusters. The laser-ablation-type cluster source is equipped for cluster generation separated from the ionization system. Two types of ionization systems are prepared: an ArF-excimer laser (193 nm, 0.8 mJ/pulse, 3 ns) or F2-excimer laser (157 nm, 0.3 mJ/pulse, 3 ns) and an electron impact ionizer. The energy and charge state of cluster ions are analyzed with a high accuracy by the sector-type 60° electrostatic analyzer with an orbital radius ρE=200 mm. The size of clusters with a specific energy and charge state is defined by the 60° magnetic analysis system characterized by an orbital radius ρM=650 mm and the maximum field strength Bmax=1.4 T. The massive ion beam system enables one to provide well mass-selected stable clusters, e.g. CuqN with sizes ranging as follows N=1–31 for q=+1 at energy E=20 keV, N=10–63 for q=+2 at E=40 keV, N=44–94 for q=+3 at E=60 keV, and N=121–126 for q=+4 at E=80 keV.

The second-harmonic (SH) spectra arising from magnetic- and electric-dipole contributions and the interference of these two channels are analyzed for antiferromagnetic ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}.$ A microscopic model which comprises boundary conditions and local-field corrections for electromagnetic waves is introduced for the nonlinear nonreciprocal optical responses. Effects of cross relaxation between the different ${\mathrm{Cr}}^{3+}$ $3d$ levels are also taken into account. Among these dissipative processes, the local-field correction for the magnetic field seems to be the most important. The origin of this correction is found to come from the presence of a coupling of orbital angular momenta of two magnetic ${\mathrm{Cr}}^{3+}$ ions which makes possible the excitation transfer between them. Only through the inclusion of this effect are the phases of the magnetic and electric susceptibilities appreciably different from each other, leading thus to the interference effect of the two channels in agreement with experimental observations.

We present a microscopic model to understand the magnetoelectric and second-harmonic spectra of ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$ and the interference effect between the magnetic $({\ensuremath{\chi}}^{m})$ and electric $({\ensuremath{\chi}}^{e})$ second-order optical polarizations. The spin-orbit interaction and the crystalline fields of correct symmetry around the ${\mathrm{Cr}}^{3+}$ ion, i.e., the axial and twisted crystalline field of ${C}_{3}$ symmetry, are treated as perturbation on the trigonal states of the ${d}^{3}$ system of ${\mathrm{Cr}}^{3+}$. By these treatments we attempt to describe the observed phenomena associated with the transitions between ${}^{4}{A}_{2g}$ and ${}^{4}{T}_{2g}$ states in ${\mathrm{Cr}}_{2}{\mathrm{O}}_{3}$. It is possible to reproduce the observed spectra of the polarization rotation and ellipticity, and the second-harmonic generation spectra described by the nonlinear susceptibilities ${\ensuremath{\chi}}^{m}$ and ${\ensuremath{\chi}}^{e}$. The estimated theoretical magnitudes of these quantities are in reasonable agreement with the observed magnitudes.

We will present a microscopic model to understand the nonreciprocal optical responses, i.e., the second-harmonic generation through electric and magnetic dipole moments and the magneto-electric effects. Here the twist crystalline field, which reflects the real crystal structure, is found to play an important role in both channels of the second-harmonic generation. Then we can explain the spectra of the second-harmonic generation through electric and magnetic dipoles. Absolute as well as relative magnitudes of the second-order susceptibilities through both channels are also estimated to be reasonable. In terms of the same model, we can also understand the magneto-electric spectra, i.e., the electric- and magnetic-dipole interference in the linear response.

Not only the selection rules for the matrix elements but also the reality of their values matter to understand microscopically the nonreciprocal optical effects in antiferromagnetic crystals. We propose a microscopic model which can explain second-harmonic generation in Cr 2 O 3 by taking account of this circumstance.

Novel concepts of X-ray production by relativistic electrons in stratified targets are developed. It is shown that by transmitting an electron beam through a compound target, consisting of a periodic multifoil structure and a crystal, it is possible to obtain the intense, tunable, quasi-monochromatic X-rays, emitting at large (Bragg) angles with respect to the electron beam axis due to the diffraction on the crystal of resonance transition radiation, previously generated in the multilayered structure. The first results of experimental investigation of this effect for 900 MeV electrons, transmitting through the periodic stack of 10 Mylar foils and pyrolytic graphite crystal, are presented. The obtained results show that, by using of the combined radiator, it is possible to produce much more intense X-rays than parametric X-ray radiation, emitting by relativistic electrons due to the diffraction of virtual photons of electron eigenfield during the electron passage through the crystal.

An extracorporeal bioartificial liver (BAL) that could prevent death from hepatic encephalopathy in acute hepatic insufficiency was aimed to develop. A functional human hepatocellular carcinoma cell line (FLC-4) was cultured in a radial-flow bioreactor. The function of the BAL was tested in mini-pigs with acute hepatic failure induced by alpha-amanitin and lipopolysaccharide. When the BAL system was connected with cultured FLC-4 to three pigs with hepatic dysfunction, all demonstrated electroencephalographic improvement and survived. Relatively low plasma concentrations of S-100 beta protein, as a marker of astrocytic damage, from pigs with hepatic failure during BAL therapy were noted. BAL therapy can prevent irreversible brain damage from hepatic encephalopathy in experimental acute hepatic failure.

We have been studying temporal characteristics of Japanese for decades. Not only acoustic measurements but also perceptual studies on temporal modification have revealed the control principles lying behind manifestation of segmental duration characteristics. This talk tries to introduce familiar generation principles such as ‘‘mora‐timing’’ and phrasal tempo reset from the viewpoint of humans temporal organization through the understanding of duration statistics. Moreover, by showing perceptual characteristics including sentential factors, we would like to propose how linguistic units relate to temporal perception and what kind of information form can be considered in temporal cognition process. Some of our recent efforts will also be presented to investigate language‐dependent temporal characteristics by observing non‐native learners temporal control characteristics. We really expect that we will be able to have a better picture of generation and perception mechanism through the cross check of their characteristic differences between natives and non‐natives. [Work supported by Waseda Univ. RISE research project of ‘‘Analysis and modeling of human mechanism in speech and language processing’’ and Grant‐in‐Aid for and Scientific Research A‐2, No. 16200016 of JSPS.]

To contribute to the naturalness criteria of speech synthesis, acceptability of changes in segment duration has been investigated. Previous studies showed context dependency of the acceptability evaluation such as intraphrase positional effect, where listeners were more sensitive to the phrase‐initial segment duration than the phrase‐final one. Such contextual effects were independent of the original durations of the segments tested [Kato et al., J. Acoust. Soc. Am. 104, 540–549 (1998)]. However, past studies used only normal‐speed speech and temporal variation was limited. The current study, therefore, examined the contextual effect with a wide variety of speaking rates. The materials were three‐mora phrases with either rising or falling accent that were spoken at three rates (fast, normal, and slow) with or without a carrier sentence. The duration of each vowel was either lengthened or shortened (10–50 ms) and listeners evaluated the acceptability of these changes. The results showed a clear speaking‐rate effect in parallel with the intraphrase positional effect: the acceptability declined more rapidly as the speaking rate became faster. These results, along with those of Kato et al., suggest that acceptability is evaluated based on the speaking rate rather than on the original duration itself. [Work supported by TAO, Japan.] a)Currently at GITI, Waseda University.

X radiation by 900 MeV electrons in accurately aligned 1–100 layers of 16 μm thick monocrystalline foils of Si was measured. We found intense and well collimated monochromatic photons, i.e. self-diffracted X rays (SDX), emitted to the “Bragg angle”. The intensity of SDX was much greater than the parametric X rays from a Si plate of equivalent thickness. For 35.5 keV X rays with 100 layered Si target, absolute brightness of SDX was comparable to the synchrotron radiation from a 1.7 GeV storage ring.