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A charge excitation in a two-dimensional Mott insulator is strongly coupled with the surrounding spins, which is observed as magnetic-polaron formations of doped carriers and a magnon sideband in the Mott-gap transition spectrum. However, the dynamics related to the spin sector are difficult to measure. Here, we show that pump-probe reflection spectroscopy with seven-femtosecond laser pulses can detect the optically induced spin dynamics in Nd2CuO4, a typical cuprate Mott insulator. The bleaching signal at the Mott-gap transition is enhanced at ~18 fs. This time constant is attributable to the spin-relaxation time during magnetic-polaron formation, which is characterized by the exchange interaction. More importantly, ultrafast coherent oscillations appear in the time evolution of the reflectivity changes, and their frequencies (1400–2700 cm−1) are equal to the probe energy measured from the Mott-gap transition peak. These oscillations can be interpreted as the interference between charge excitations with two magnons originating from charge–spin coupling., Understanding the dynamics of cuprates following photoexcitation can provide insights into the complex coupling mechanisms that underlie their exotic equilibrium behaviour. Here the authors use pump-probe reflection spectroscopy to investigate the nonequilibrium spin dynamics of Mott-insulating Nd2CuO4.

The transition of a Mott insulator to metal, the Mott transition, can occur via carrier doping by elemental substitution, and by photoirradiation, as observed in transition-metal compounds and in organic materials. Here, we show that the application of a strong electric field can induce a Mott transition by a new pathway, namely through impulsive dielectric breakdown. Irradiation of a terahertz electric-field pulse on an ET-based compound, κ-(ET)

Mott insulators sometimes show dramatic changes in their electronic states after photoirradiation, as indicated by photoinduced Mott-insulator-to-metal transition. In the photoexcited states of Mott insulators, electron wavefunctions are more delocalized than in the ground state, and long-range Coulomb interactions play important roles in charge dynamics. However, their effects are difficult to discriminate experimentally. Here, we show that in a one-dimensional Mott insulator, bis(ethylenedithio)tetrathiafulvalene-difluorotetracyanoquinodimethane (ET-F2TCNQ), long-range Coulomb interactions stabilize not only excitons, doublon-holon bound states, but also biexcitons. By measuring terahertz-electric-field-induced reflectivity changes, we demonstrate that odd- and even-parity excitons are split off from a doublon-holon continuum. Further, spectral changes of reflectivity induced by a resonant excitation of the odd-parity exciton reveals that an exciton-biexciton transition appears just below the exciton-transition peak. Theoretical simulations show that long-range Coulomb interactions over four sites are necessary to stabilize the biexciton. Such information is indispensable for understanding the non-equilibrium dynamics of photoexcited Mott insulators., Comment: 30 pages including 4 figures and 1 table (Supplementary Informations: 8 pages including 5 figures)

The authors present the apparent improvement of quality of La 2 CuO 4 (LCO) thin films with the introduction of an amorphous layer (AL) of LCO. The samples were grown on LaSrAlO 4 substrates by pulsed laser deposition. X-ray diffraction (XRD) measurements demonstrate that the introduction of the AL of LCO significantly improves the structural quality of LCO thin films. The linewidth of XRD peaks is significantly narrowed down to 129 arcsec. Atomic force microscopy (AFM) shows that the surface precipitates are sufficiently suppressed for the LCO films with ALs. The spectra of optical absorption indicate that the ALs can improve the stoichiometry of the LCO films. The mechanism for the improved quality of LCO films with the ALs is discussed based on the results of XRD and AFM measurements.

In microcrystal samples of the prototypical organic molecular semiconductors rubrene and C10-DNTT (2,9-didecyl-dinaphtho[2,3-b:2′,3′-f]thieno[3,2-b]thiophene), we measured spectra of complex optical conductivity caused by photocarriers with optical-pump terahertz-probe spectroscopy. We analyzed the σ ω spectra using the Drude-Smith model and evaluated the DC mobility μ DC, which includes extrinsic effects, and the intrinsic mobility μ int. The resulting μ DC and μ int values are comparable to the mobility values obtained using transport measurements of polycrystalline and single-crystalline field-effect transistors, respectively. This correspondence demonstrates that the intrinsic mobility values of organic molecular semiconductors can be evaluated from the measurements of microcrystal samples using transient terahertz spectroscopy.

Although distance dependence of Förster resonance energy transfer (FRET) is well-studied and FRET has been extensively applied as "molecular ruler", only limited examples of orientation-dependent FRET have been reported. To create a robust FRET system that precisely reflects the orientation between donor and acceptor, donor and acceptor fluorophores were introduced into a DNA via a D-threoninol scaffold. Strong stacking interactions among intercalated dyes and natural base-pairs suppress free movement of the dyes, clamping them in the duplex in a fixed orientation. Pyrene and perylene were used as donor and acceptor, respectively, and both the distance and orientation between these dyes were systematically controlled by varying the number of intervening AT pairs from 1 to 21 (corresponding to two turns of helix). FRET efficiency determined from static fluorescence measurement did not decrease linearly with the number (n) of inserted AT pairs but dropped significantly every 5 base pairs (i.e., n = 8, 13, and 18), corresponding to a half-turn of the B-type helix. This clearly demonstrates that FRET efficiency reflects the orientation between pyrene and perylene. We also measured time-resolved fluorescence spectroscopy with a streak camera and successfully observed the time-course of the energy transfer directly. As expected, the FRET efficiencies determined from the lifetime of pyrene emission were in good agreement with static measurements. Theoretical calculation of FRET efficiency assuming that the DNA duplex is a rigid cylinder with B-type geometry coincided with the experimental results. We believe that our method of using d-threoninol will contribute to further development of FRET-based measurement techniques.

We measured the optical conductivity $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\sigma}}(\ensuremath{\omega})$ spectra caused by photocarriers in anatase $\mathrm{Ti}{\mathrm{O}}_{2}$ by applying ultraviolet-pump terahertz-probe spectroscopy on epitaxially grown thin films. Drude model analyses of $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\sigma}}(\ensuremath{\omega})$ spectra reveal that, in the terahertz region, the reduced mass ($\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{m}$) of the carriers is greater and their damping constant ($\ensuremath{\gamma}$) is smaller than those in the infrared region. With regard to the extended Drude model, these differences can be attributed to the frequency dependence of $\stackrel{\ifmmode \hat{}\else \^{}\fi{}}{m}$ and $\ensuremath{\gamma}$ originating from carrier-phonon scatterings. Furthermore, the interaction between carriers and Ti-O stretching modes in the $500--1000\ensuremath{-}\mathrm{c}{\mathrm{m}}^{\ensuremath{-}1}$ region strongly influences the intrinsic carrier scattering mechanism in anatase $\mathrm{Ti}{\mathrm{O}}_{2}$.

To control the efficiency of photoinduced charge-order melting in perovskite manganites, we performed femtosecond pump-probe spectroscopy using double-pulse excitation on Pr_{0.6}Ca_{0.4}MnO_{3}. The results revealed that the transfer of the spectral weight from the near-infrared to infrared region by the second pump pulse is considerably enhanced by the first pump pulse and that the suppression of crystal anisotropy, that is, the decrease of long-range lattice deformations due to the charge order by the first pump pulse is a key factor to enhance the charge-order melting. This double-pulse excitation method can be applied to various photoinduced transitions in complex materials with electronic and structural instabilities.

To control the efficiency of photoinduced charge-order melting in perovskite manganites, we performed femtosecond pump-probe spectroscopy using double-pulse excitation on Pr_{0.6}Ca_{0.4}MnO_{3}. The results revealed that the transfer of the spectral weight from the near-infrared to infrared region by the second pump pulse is considerably enhanced by the first pump pulse and that the suppression of crystal anisotropy, that is, the decrease of long-range lattice deformations due to the charge order by the first pump pulse is a key factor to enhance the charge-order melting. This double-pulse excitation method can be applied to various photoinduced transitions in complex materials with electronic and structural instabilities.

In electronic-type ferroelectrics, where dipole moments produced by the variations of electron configurations are aligned, the polarization is expected to be rapidly controlled by electric fields. Such a feature can be used for high-speed electric-switching and memory devices. Electronic-type ferroelectrics include charge degrees of freedom, so that they are sometimes conductive, complicating dielectric measurements. This makes difficult the exploration of electronic-type ferroelectrics and the understanding of their ferroelectric nature. Here, we show unambiguous evidence for electronic ferroelectricity in the charge-order (CO) phase of a prototypical ET-based molecular compound, α-(ET)2I3 (ET:bis(ethylenedithio)tetrathiafulvalene), using a terahertz pulse as an external electric field. Terahertz-pump second-harmonic-generation(SHG)-probe and optical-reflectivity-probe spectroscopy reveal that the ferroelectric polarization originates from intermolecular charge transfers and is inclined 27° from the horizontal CO stripe. These features are qualitatively reproduced by the density-functional-theory calculation. After sub-picosecond polarization modulation by terahertz fields, prominent oscillations appear in the reflectivity but not in the SHG-probe results, suggesting that the CO is coupled with molecular displacements, while the ferroelectricity is electronic in nature. The results presented here demonstrate that terahertz-pump optical-probe spectroscopy is a powerful tool not only for rapidly controlling polarizations, but also for clarifying the mechanisms of ferroelectricity.

We measured the optical conductivity $\stackrel{\ifmmode \tilde{}\else \~{}\fi{}}{\ensuremath{\sigma}}(\ensuremath{\omega})$ spectra of photodoped silicon by optical-pump terahertz-probe spectroscopy and analyzed them with a two-carrier Drude model. Taking into account the values of electron (hole)-phonon scattering rates previously reported in chemically doped silicon, we evaluated the electron-hole scattering rates ${\ensuremath{\gamma}}_{\mathrm{e}\ensuremath{-}\mathrm{h}}$. From 293 to $90\phantom{\rule{0.16em}{0ex}}\mathrm{K}$, the magnitudes and temperature dependence of ${\ensuremath{\gamma}}_{\mathrm{e}\ensuremath{-}\mathrm{h}}$ were successfully reproduced by a theoretical model including the effects of Rutherford scattering, Coulomb screening, and Pauli exclusion. This suggests that these three factors dominate electron-hole scattering processes in silicon. Below $90\phantom{\rule{0.16em}{0ex}}\mathrm{K}, {\ensuremath{\gamma}}_{\mathrm{e}\ensuremath{-}\mathrm{h}}$ becomes larger than that of the theoretical curve, which is attributable to a prolongation of the relaxation time of hot carriers.

Photoinduced melting of the spin-Peierls phase was investigated in Na-tetracyanoquinodimethane by pump-probe reflection spectroscopy with a time resolution of 49 fs. Photoirradiation generates coherent molecular oscillation, which indicates that the spin-Peierls dimerization decreased. Increasing the excitation photon density to $g0.02$ photon/molecule doubles the oscillation frequency attributable to recovery of the original symmetry, that is, complete melting of the spin-Peierls phase. We observed a complete photoinduced transition with symmetry recovery revealed by frequency doubling of coherent oscillations.

International audience; Carrier dynamics of an organic molecular semiconductor, rubrene, was investigated by optical- pump terahertz-probe spectroscopy from 1 to 15 THz. At 294 K, a Drude-like response due to pho- togenerated hole carriers is observed below 8 THz. The real part r1ðxÞ of the optical conductivity is suppressed below 2 THz, indicating the presence of a localization effect. Such a spectral feature was reproduced by a Drude-Anderson model including the effect of dynamical disorder due to intermolecular vibrations. At 50 K, the spectral weight of r1 ðxÞ due to photocarriers shifts to lower frequency below 4 THz and the suppression of r1ðxÞ is hardly observed, which we associate with a reduction of thermal molecular motions. The overall photocarrier generation and recombination dynamics is also discussed.

Using strong terahertz fields, we succeeded in rapidly modulating ferroelectric polarizations in electronic-type ferroelectrics of molecular crystals, TTF-CA and croconic acid. Polarization modulations are attributable to collective inter- or intra-molecular charge-transfers induced by terahertz field.

We report a new photoinduced transition from a nonordered phase to a transient ordered phase with symmetry breaking in an organic charge-transfer compound, dimethyltetrathiafulvalene (DMTTF)-dibromodichloro-$p$-benzoquinone ($2,6Q{\mathrm{Br}}_{2}{\mathrm{Cl}}_{2}$), which is a neutral compound located near the neutral-ionic phase boundary and shows quantum paraelectricity at low temperatures. By an irradiation of a femtosecond laser pulse, an ionic domain consisting of $\ensuremath{\sim}40$ molecules is introduced into the neutral lattice per photon, giving rise to coherent molecular oscillations with fractional charge modulations over $\ensuremath{\sim}400$ molecules. This response is due to the recovery of ferroelectric nature from the quantum paraelectricity by a photoinjection of an ionic domain with a large dipole moment.

Ferroelectrics sometimes show large electro-optical and non-linear optical effects, available for polarization rotation and frequency conversion of light, respectively. If the amplitude of ferroelectric polarization is modulated in the picosecond time domain, terahertz repetition of optical switching via electro-optical and non-linear optical effects would be achieved. Here we show that polarization amplitude can be rapidly modulated by a terahertz electric field in an organic ferroelectric, tetrathiafulvalene-p-chloranil (TTF-CA). In this compound, alternately stacked donor (TTF) and acceptor (CA) molecules are dimerized via the spin-Peierls mechanism, and charge transfer within each dimer results in a new type of ferroelectricity called electronic-type ferroelectricity. Using a terahertz field, the intradimer charge transfer is strongly modulated, producing a subpicosecond change in the macroscopic polarization, which is demonstrated by transient reflectivity and second-harmonic generation measurements. Subsequently, coherent oscillation of the dimeric molecular displacements occur, which is explained by the modulation of the spin moment of each molecule., Controlling ferroelectric polarization on a terahertz timescale is a challenge, because typically the domain-wall motion occurs on much longer time scales. Here, the authors achieve control over the electronic ferroelectricity in an organic material using a terahertz pump–probe technique.

The performance of a simple servo-derived clocking scheme for magnetic disk recording channels is presented. Using a theoretical model, the bit clock jitter is analyzed by computer simulation, and it is shown that in the bit clock jitter the mechanical-component (velocity jitter) is more influential than the jitter component which originates from the position noise in the detected clock mark readback pulse. Cancellation error of an eccentricity jitter component between writing and reading moments due to PLL (Phase-Locked Loop) gain variation can be reduced by a feed-forward eccentricity suppression technique. Part of simulation results are verified by jitter measurements using an experimental recording channel, a patterned magnetic disk and an MR/Inductive head. Bit clock jitter of less than 2.5 ns(rms) is obtained for a spindle with air-bearing, supporting the analytical results. The simple servo-derived clocking scheme can be used in magnetic disk drives with a data rate of 20 Mbit/s or more.

A coherent digital maximum-likelihood (ML) head position estimator was proposed and examined for sampled-servo magnetic disk drives. Estimating the ML head position is obtained through four ML amplitude estimators of each servo mark readback pulse. When compared to a conventional analog integration detector about 1.7 dB improvement in position estimation accuracy was obtained. To generate a servo clock for coherent estimation, an ML phase estimating digital phase-locked loop (DPLL) was also developed. Since five inner product operations for amplitude and phase estimation are performed by a time-shared multiplier-accumulator, this ML head position estimator is applicable for use in small scale hardware and adaptable to ICs.

To determine whether a newly developed PERM (Pre-Embossed Rigid Magnetic) disk can be used with an MB/inductive head and a PRML (Partial-Response Maximum-Likelihood) channel, an experimental digital magnetic recording system was developed. This system used an external clocking scheme instead of a conventional self-clocking scheme. The track pitch was 5.2 /spl mu/m, and the track width was 3.6 /spl mu/m. Basic read-write characteristics, such as signal-to-noise ratio, frequency response, positive/negative symmetry or the readback pulse, were measured. An areal density of 605 kbit/mm/sup 2/ (390 Mbit/inch/sup 2/) was obtained at a bit error rate of 10/sup -6/. >

The relaxation dynamics of an exciton in rubrene was investigated by femtosecond absorption spectroscopy. Exciton relaxation to a self-trapped state occurs via the coherent oscillation with 78 cm(-1) due to a coupled mode of molecular deformations with phenyl-side-group motions and molecular displacements. From the temperature dependence of the decay time of excitons, the energy necessary for an exciton to escape from a self-trapped state is evaluated to be ~35 meV (~400 K). As a result, a self-trapped exciton is stable at low temperatures. At room temperature, excitons can escape from a self-trapped state and, subsequently, they are dissociated to charged species. The exciton dissociation mechanism is discussed on the basis of the results.

A 13-week oral repeated dose toxicity study of suplatast tosilate (IPD-1151T), a new anti-allergic agent, as well as a 5-week recovery study were carried out at dose levels of 0 (control), 50, 150, 450 and 1350 mg/kg/day using male and female beagle dogs. The results were as follows: 1. In general conditions, soft feces and diarrhea with specific smell were dose-dependently observed in males and females given 450 mg/kg/day or more. Both sexes given 1350 mg/kg/day, revealed reeling with dropped head, abnormal gait, dysstasia, lying at lateral or prone position, sedation, and tremor, and one male and one female in this group died after showing respiratory depression, collapse and cyanosis. 2. There were no significant or remarkable changes in body weight, food consumption, water consumption, ophthalmology, electrocardiogram, urinalysis, hematology, biochemistry, fecal occult blood test, and absolute and relative organ weights. 3. Pathological examination in dead animals revealed hemorrhagic change in the heart and slight vacuolar changes in hepatocytes. In survived animals, there were no pathological changes attributable to the IPD-1151T. 4. In electron microscopic examination, there were no abnormalities in the liver and kidney attributable to the IPD-1151T. 5. After 5-week recovery period, above-mentioned changes disappeared. 6. From the above results, the non-effective dose level and the toxic dose level were estimated to be 150 mg/kg/day and 1350 mg/kg/day, respectively, and no sex differences were found.

A new delay compensation method is derived for servo systems using state prediction control and disturbance observer. The delay in the closed loop deteriorates the stability margin because of the phase delay in high frequency region. The proposed method consists of three steps, (1) state estimation with state observer, (2) state prediction, and (3) state feedback of predicted state. For SISO(single input, single output) systems, the proposed method can be rewritten in the scheme of conventional disturbance observer design by using Youla parameterization. This result can be drawn by the analysis of the closed loop system poles and by applying the separation theorem. Improvement of the stability margin is confirmed by simulation in the track following mode of a hard disk drive with the synchronous servo scheme.

The present study investigated methods for bonding between semiconductor bonding pads and the metal bumps of a film carrier developed for use in chip-size packages (CSP). The structure of the film carrier is that of a copper circuit bearing a layer of insulating polyimide (PI) on both sides and connecting on one side with the exposed bumps, which in turn connect with the bonding pads. The bumps either have a copper core with a gold surface, or are all gold. In the first stage of the experiment, in which basic data were gathered, the ability of the bumps to bond via gang-bonding with the aluminum of the silicon chip was tested, using bumps with gold-plating of different thicknesses to give exposed heights of 10, 30 and 50 /spl mu/m. Bump height is a decisive factor in the peeling strength of the bonding site; satisfactory results were not achieved with low bumps of 10 /spl mu/m height. In the second stage, a method was sought which would help minimize production cost by ensuring successful bonding even with bumps of only 10 /spl mu/m height. The three following methods were tested and found effective: (1) inserting a convex frame immediately beneath the film carrier on the side opposite the bumps; (2) using a film carrier containing a layer of thermoplastic material immediately beneath the bumps; and (3) undertaking scrubbing during the initial bonding phase.

Presents a multi-loop adaptive feedforward cancellation (AFC) in order to compensate for the repeatable runout (RRO) in disk file systems such as a disk eccentricity not only in the track following mode but also in the seek mode. By using a double-loop AFC, a cancellation of the fundamental RRO component with fixed coefficients is applied in the seek mode, resulting in a stable settling characteristic which is independent of the disk eccentricity. In the track following mode, the first four harmonic components of the RRO are cancelled so that each harmonic component of a position error is reduced to less than 0.01 /spl mu/m/sub 0-p/.

For magnetic recording channels with EPR4 signaling, a rate 16/18 (0,6) trellis code and a time-varying Viterbi detector for the code are proposed and examined. A method to construct the code that has a pseudo matched spectral null (MSN) at the Nyquist frequency is described. We show that the TC-EPR4ML detection with the proposed 16/18 (0,6) code can provide 1.5 dB and 1 dB gains compared to the conventional 16/17 EPR4ML and 16/18 TC-PR4ML detection respectively at a user bit density of 2.5.

The dynamics of photogenerated electrons and holes in undoped anatase TiO2 were studied by femtosecond absorption spectroscopy from the visible to mid-infrared region (0.1–2.0 eV). The transient absorption spectra exhibited clear metallic responses, which were well reproduced by a simple Drude model. No mid-gap absorptions originating from photocarrier localization were observed. The reduced optical mass of the photocarriers obtained from the Drude-model analysis is comparable to theoretically expected one. These results demonstrate that both photogenerated holes and electrons act as mobile carriers in anatase TiO2. We also discuss scattering and recombination dynamics of photogenerated electrons and holes on the basis of the time dependence of absorption changes.

We have investigated the possible role of theca and granulosa cell interaction in the control of the hormone-producing activity and growth of granulosa and theca cells during bovine ovarian follicular development, using a coculture system in which granulosa and theca cells were grown on opposite sides of a collagen membrane. When follicular cells were isolated from small follicles (3-5 mm), theca cells reduced estradiol, progesterone, and inhibin production by granulosa cells to 14 +/- 5%, 64 +/- 6%, and 27 +/- 4%, respectively, of the production by granulosa cells cultured alone. On the other hand, when the cells were isolated from large follicles (15-18 mm), theca cells increased these levels to 253 +/- 34%, 156 +/- 24%, and 287 +/- 45%, respectively. Theca cells did not affect the growth of granulosa cells. Androstenedione production by theca cells was augmented by granulosa cells to 861 +/- 190% (in small follicles) and 1298 +/- 414% (in large follicles), respectively. The growth of theca cells was also augmented by granulosa cells (small follicle, 210 +/- 43%, and large follicle, 194 +/- 24%, respectively). These results indicate that theca cells secrete factor(s) inhibiting the differentiation of immature while promoting that of matured granulosa cells; they also suggest that granulosa cells secrete factor(s) promoting both the differentiation and growth of theca cells throughout the follicular maturation process.

Polarized absorption spectra of hole carriers in rubrene single crystal field-effect transistors were measured in the infrared region (725–8000 cm−1) by charge modulation spectroscopy. The absorptions, including the superimposed oscillatory components due to multiple reflections within thin crystals, monotonically increased with decreasing frequency. The spectra and their polarization dependences were well reproduced by the analysis based on the Drude model, in which the absorptions due to holes in rubrene and electrons in the gate electrodes (silicon), and multiple reflections were fully considered. The results support the band transport of hole carriers in rubrene.

Sub-picosecond modulation of the optical reflectivity (R) using terahertz electric-field (ETHz) pulses was achieved in a typical one-dimensional Mott insulator, the bromine-bridged nickel compound, [Ni(chxn)2Br]Br2 (chxn: cyclohexanediamine). The reflectivity change (ΔR/R) at around the Mott-gap transition peak (∼1.3 eV) was ∼1% for ETHz ∼45 kV/cm, and proportional to the square of ETHz. The relaxation time of ΔR/R was under 0.1 ps, enabling optical switching with a high repetition rate in the near-infrared region. The electric-field and probe-energy dependences of ΔR/R demonstrate that the modulation is due to large third-order optical nonlinearity of one-dimensional Mott insulators.

The prevention of viral hepatitis caused by blood transfusion is the most serious problem at this present, as hepatitis viral agent has not been identified, and there is no specific measure to detect a silent carrier of viral agent.In 1961, isolation of agent, with using a human embryonic lung cell culture, from the blood of volunteers who developed serum hepatitis after inoculation of U. S. N. I. H. icterogenic plasma pool No. 6 has been reported by Bolin.HIM (Hepatitis-Infectious Mononucleosis) test is a serological examination for detecting a specific antibody in serum with using agglutination of latex particles which are coated with its viral agent isolated by Bolin. This viral antigen has many problems which must be solved since not being out of the position of candidate. From the view of a high positive rate found by Bolin and also by us in screening the cases of Suspective Viral Hepatitis, this study was made to seek for possibility of preventing viral hepatitis after the blood transfusion by applying the HIM test to screen donor's blood before transfusion. The results obtained were summalized as follows:1) Total 4, 009 cases of normal donors sera were screened by HIM qualitative test and 42.8% of these specimens gave positive result.2) A little difference was shown in the positivity of HIM screening test between the groups of donor classified by age, sex and blood groups.3) A linear relationship was not found to exist between the results obtained by HIM screening test and SGO-T screening test for the same donors serum.4) By the HIM qualitative screening test with the use of the serum dilution of 1:5, the blood which had been shown to be under 40 units by SGO-T screening test (Whetzel method) were sort out to HIM positive blood and negative ones. These blood were transfused to the patients who had needed the blood transfusion except of liver and bile duct deseases. Recipients were classified with using these HIM positive blood or negative ones by the blood transfused to each group. Each recipient group was followed up for about a 6 month on their clinical conditions and liver function (mainly Serum transaminase level).The incidence of liver dysfunction was investigated in both these two recipient groups, and the incidence of liver dysfunction in HIM negative blood recipients group was only a half as in HIM positive blood recipient group. In case of excluding the cases which had been suffered from cancer from all the followed-up cases, the incidence of dysfunction in the HIM negative recipient group was only one third as in the HIM positive blood recipient group. This difference was found to be statistically significant at 5% level.Thus, from these findings, it is suggested that HIM screening test is effective for the donor screening method to prevent the viral hepatitis after transfusion.

In order to realize the on-line prediction and on-line control of mechanical properties of steels, efforts are being made on modelling the evolution of microstructure and resulting mechanical properties. This paper describes the present state of things about such modelling in hot strip rolling based on the authors' own experience. Corresponding to the high-speed, continuous hot strip rolling, a new hot deformation model was developed. A new type of transformation model was also developed, since the conventional Johnson-Mehl type time-dependent equation is difficult to be applied to low-carbon strip steels with higher transformation rate. The transformation temperature calculated by this model was found to have linear relationship with the microhardness of the corresponding microconstituent. The tensile strength calculated from the above transformation temperature agreed well with the observed values. The prospect of the application of such models to production was surveyed, including the on-line control system of mechanical properties.

The relations between the compression ratio and the leak of some rubber gaskets having practical dimensions were investigated by a helium leak detector. As the materials of the samples we used aerylenttrile butadiene, chloroprene, natural and silicone rubber. Testing was tried for three different kinds of cross-section; circular, semicircular and square, and also for the gaskets of seven different Shore hardness from 30 to 90. Five jointless pieces for each kind of samples (420 pieces in total) are made as samples to be tested, there are two kinds of the leak in a gasket sealing, namely usual “leak” and “permeation”. The former is a leak through the space between the surface of a gasket and that of a gasket seat, and the latter is a leak through the gasket material itself These two kinds of leak can be distinguished clearly by experiment. The former leak can be made less than 1 × 10−9 mmHg l./s when rubber of any kind is compressed by 10 15%.