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Many reports describe overestimation of liquefaction resistance based on sounding data related to ground materials containing coarse particles such as gravel and cobbles. Better methods of liquefaction potential estimation must be developed using investigation data other than those from sounding. Gathering perfect and undisturbed samples is difficult, but using seismic methods such as PS logging might be effective for assessing liquefaction potential. For this study, bender element (BE) tests and local small strain (LSS) tests were conducted, respectively, to measure the dynamic and static shear moduli of gravel--mixed sand specimens. Subsequently, relations between liquefaction strength and secant shear moduli were examined to provide reliable estimation of liquefaction in gravel--mixed sand. Although the liquefaction resistance increased considerably with overconsolidation, the initial shear modulus exhibited only a slight change with the same overconsolidation. The experimentally obtained results elucidated that the important shear strain level, for which secant shear modulus has a strong relation with liquefaction strength, was not a linear elastic region of 0.001%: it was about 0.01%. Key words: bender element test, cyclic triaxial test, deformation characteristic, gravel content, liquefaction, overconsolidation, sand. De nombreux rapports decrivent une surestimation de la resistance a la liquefaction basee sur des donnees de sondage relatives a des materiaux broyes contenant des particules grossieres telles que du gravier et des galets. De meilleures methodes d'estimation du potentiel de liquefaction doivent etre developpees a l'aide de donnees d'enquete autres que celles obtenues par sondage. Il est difficile de collecter des echantillons parfaits et non perturbes, mais l'utilisation de methodes sismiques telles que <> peut s'averer efficace pour evaluer le potentiel de liquefaction. Pour cette etude, des essais d'elements piezoceramiques (<>) et des essais de petites deformations locales (<>) ont ete realises, respectivement, pour mesurer les modules de cisaillement dynamique et statique d'echantillons de sable melange a du gravier. Ensuite, les relations entre la resistance a la liquefaction et les modules de cisaillement secant ont ete examinees afin de fournir une estimation fiable de la liquefaction dans du sable melange avec du gravier. Bien que la resistance a la liquefaction augmente considerablement avec la surconsolidation, le module de cisaillement initial ne presente qu'un leger changement avec la meme surconsolidation. Les resultats obtenus experimentalement ont permis de comprendre que le niveau de contrainte de cisaillement important, pour lequel le module de cisaillement secant a une relation etroite avec la resistance a la liquefaction, n'etait pas une region elastique lineaire de 0,001% : il etait d'environ 0,01%. [Traduit par la Redaction] Mots-cles : essais d'elements piezoceramiques, essais triaxiaux cycliques, caracteristique de deformation, teneur en gravier, liquefaction, surconsolidation, sable., Introduction Measurements of soil properties in the ground must be taken to estimate the safety factor of liquefaction, as defined by the ratio between the cyclic resistance ratio (CRR) against [...]

The design of the single-flux-quantum (SFQ) circuits which was estimated by applying over- and under-ground planes to minimize the parasitic inductances to determine its sheet inductances of base and counter superconducting layers is described.

A design of an up/down counter composed of 4-Junction Logic (JL) gates and the digital/analog (D/A) converter using an R-2R ladder circuit is presented to realize the digital flux locked-loop (FLL) circuit. The 4 JL gates with the Superconducting QUantum Interference Device (SQUID) regulator is developed and the correct logic operations are successfully confirmed using fabricated 4JL gates.

Photosensitive polyimide insulation layers are introduced to fabricate superconducting integrated circuits. It simplifies the fabrication process, because the photosensitive polyimide insulation layer can be patterned by conventional photolithography process, resulting in the etching process unnecessary in the present new fabrication process.

An innovative phonon detector in which the integrated coil and the normal-distribution junction are combined is described and discussed.

Nb1-xTixN thin films were prepared using reactive dc magnetron sputtering, and superconducting properties were found to be strongly linked to sputtering conditions.

Normal-distribution-shaped Josephson tunnel junctions for superconducting tunnel junction photon detector applications have been investigated.

CeO2 insulating film was utilized as a high temperature multilayer in the fabrication of a YBaCuO crossover. An adequate critical temperature of 87 L and critical current density of 1.0x10(super 5) A/cm2 were observed at the bottom YBaCuO bridges. Top bridges, however, exhibited a lower critical current density because the grain boundaries were developed at the bottom bridge's step edges.

X-ray irradiation was used to test a 200 micrometer x 200 micrometer surface area high-quality niobium-based superconducting tunnel junction. Application of a magnetic field with various ramping speeds revealed two types of stable operation modes. The single electron collection's higher mode operation energy requirement was 6.5 meV. Excellent response to x-rays of 5.9 keV and full width at half maximum of 93 eV were observed in the tunnel junction.

Experiments are performed to determine the feasibility of using superconducting tunnel junctions for high-energy resolution, x-ray detection. Characteristics of Nb-based junctions are studied to detect their responses to x-rays from synchrotron radiation. The dependence of the detector pulse height on x-ray energies falls somewhere between 4 and 15 keV.

A new etching process is proposed for fabricating submicron Nb/AlOx/Nb Josephson junctions for large-scale integration applications. The process uses a dummy etching process to improve the anisotropy in a reactive ion etching scheme. A scanning electron microscope is employed as an etching-end detector. The proposed etching scheme is very useful for producing high-quality submicron junctions with suitable critical current variations.

The effect of temperature on the critical current density profile of (103)-oriented YBaCuO/PrBaCuO/YBaCuO trilayer Josephson junctions is investigated by measuring their current-voltage characteristics at different temperatures. Results show that the junctions' critical current increases drastically at around 40 degrees Kelvin as temperature rises. This current decreases towards the critical temperature of the junctions.

A standard cell method that combines a routing process and automatic placement process yields a chip layout design for a high-speed Josephson LSI circuit comprising 1,500 gates that help analyze high-speed operability of a clock frequency of one GHz. A circuit dividing method that decreases the power supply circuit size and power wire length helps incorporate high frequency power into the chip layout design. A power load balancing technique achieves a steady power supply circuit operation.

The fabrication of all-oxide superconductor-normal metal-superconductor junction structures by the in-situ deposition of YBaCuO/PrBaCuO/YBaCuO trilayer films on a (100)MgO single crystal substrate is discussed. The junctions were patterned on the substrate using a conventional photolithographic technique. A gold layer was also deposited on the surface of the trilayer films to eliminate the influence of moisture and photoresist process. Experimental results show that the structures have a supercurrent with a small resistance connected in series to the junctions.

A proposed method for reducing logic delay uses a high Josephson critical current density with minimal junction area and is applied in the production of submicron NbN-MgO-NbN Josephson junctions. The resulting logic circuit is composed of junctions measuring 0.9 micrometers square. A minimum logic delay of 3.6 picosecond per gate is observed in the delay measurement resulting in a plus or minus 17% operating margin within 50 gates.

A major obstacle to the further miniaturization and higher speed of computers is the dissipation on an integrated circuit chip. The use of Josephson junction devices is potentially a solution to this problem and much research was done in 1980s. Results were disappointing, mainly because of technical problems in making stable junction electrodes. Recently, however, a new approach by Japanese workers shows how these difficulties may be overcome and computers based on the Josephson effect are again the subject of much research.

An Nb-based superconducting tunnel junction (STJs) is fabricated with Al trapping layer using the photosensitive polyimide insulation layer and was detected for X-ray irradiation. It was found that the method of using the photosensitive polyimide insulation layer practically applicable as X-ray detector.

A phonomediated radiation detector using Nb-based superconducting tunnel junctions is developed that are fabricated on an Al2O3 and LiNbO3 substrates. It is found that the maximum pulse height of the phonon events for the LiNbO3 substrate is about twice of that for the Al2O3 substrate.elp

Fabrication of Nb-based suerconducting tunnel junctions (STJ) with [beta]-Ta trapping layers is described and discussed.

In recent years, linear motors are gaining wide popularity in the field of office and factory automation. Therefore, small and high thrust linear motors are needed. This paper deals with a proposal of a new interior permanent magnet type linear pulse motor and it's characteristics. The thrust density of the interior permanent magnet linear pulse motor is larger compared to the other type linear pulse motors. [ABSTRACT FROM AUTHOR]

We have developed a Phononmediated radiation detector using Nb-based superconducting tunnel junctions (STJs). The STJs are fabricated on a substrate as an absorber of the radiation, and a substantial amount of emergent phonons with an energy above the energy gap are detected. The performance of the detector depends on the collection efficiency of the phonon. A selection of an appropriate substrate is required for optimizing the detector performance. We fabricated Nb-bass STJs on a Al2O3 and a LiNbO3 substrates, and compared the pulse heights of substrate phonon events due to X-ray irradiation to the substrates. We found that the maximum pulse height of the phonon events for the LiNbO3 substrate was about twice of that for the Al2 O3 substrate, so that these spectra which was obtained from two STJs showed different shapes, especially the peak due to phonon events. [ABSTRACT FROM AUTHOR]

We have successfully fabricated Nb-based superconducting tunnel junctions (STJs) with β-Ta trapping layers. In an Nb/ β-Ta stacked structure, β-Ta film showed the thickness dependence of critical temperature T[sub c] in current-voltage (I-V) characteristics due to the proximity effect from Nb films. We fabricated Nb-based STJs with Β-Ta trapping layers for X-ray detector working at 0.4 K. We obtained an energy resolution of 52 eV for 5.9 kev X-ray irradiation at 0.4 K. We expect a high energy resolution by optimizing the thickness of Β-Ta trapping layers and improving the fabrication process. [ABSTRACT FROM AUTHOR]

Switching functions using a parallel connection of conventional-type and πtype junctions have been investigated. Both junctions consist of Nb/Au/YBa[sub 2]Cu[sub 3]O[sub 7]-δ Josephson junctions on YBa[sub 2]Cu[sub 3]O[sub 7]-δ edges, whose faces are (110) and (100). The modulation patterns of critical currents in low magnetic fields indicate that the d-wave component is dominant: the (100) junctions exhibit the conventional type, but the (110) junctions the π type. Superconducting current path is alternated between the conventional junction and the π junction by applied magnetic fields using these anisotropic magnetic field dependences of the critical current. [ABSTRACT FROM AUTHOR]

Demonstrates the anisotropic Josephson effect in all (103)-oriented junctions consisting of YBa[sub 2]Cu[sub 3]O[sub 7-delta]/PrBa[sub 2]Cu[sub 3]O[sub 7-delta']/YBa[sub 2]Cu[sub 3]O[sub 7-delta] films. Characteristics of the junction; Use of the junction isolation technology; Exhibition of anisotropic Fraunhofer interference patterns.

We have investigated the magnetic field dependence of the Josephson tunnel junctions whose shape is defined with a normal-distribution function. It was revealed that the normal-distribution-shaped Josephson tunnel junctions show an exponential decay and no side lobes of the Josephson current as the external magnetic field is increased. This behavior was confirmed experimentally by using the Nb/AlO[sub x]/Nb tunnel junctions with a Josephson critical current density of J[sub c]=50 A/cm[sup 2], and an area of 10 000 μm[sup 2] corresponding to the "small" junction region. Normal-distribution junctions should have a potential for wide applications to photon detection since the external magnetic field to suppress the Josephson current can be lowered to less than one tenth that of other junctions reported. © 2000 American Institute of Physics. [ABSTRACT FROM AUTHOR]