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Grounds subjected to cyclic loading, either continuous or fragmentary, widely exist in natural deposits and at reclaimed sites, e.g., induced by traffic loads, earthquakes, and wave-induced loading environments. Assessing the ground deformation under cyclic loading conditions is necessary for proper design and maintenance planning for traffic services. Accordingly, a testing program, in which vertical, horizontal, and shear stresses are automatically controlled, were newly developed in this study to reproduce the actual cyclic traffic load conditions using a hollow-cylindrical torsional shear apparatus.

This paper presents the effects of inherent anisotropy on the shear strength and shear modulus of both saturated and unsaturated sands. Several triaxial compression tests were performed using Toyoura sand with different contents of mica: 0%, 1%, 2.5%, 5%, and 10%. Specimens with various deposition angles αwere prepared using the air pluviation (AP) and dry vibration (DV) methods. The shear strength properties were measured by conventional triaxial tests, whereas the small strain stiffness was measured by both local small strain (LSS) tests and bender element (BE) tests. The orientation of the sand particles was assessed based on two-dimensional optical microscopic measurements and mathematical estimation. The results showed that an increase in the mica content brought about a decrease in the degree of anisotropy of the shear strength because of mica particle breakage. However, the degree of anisotropy of the shear modulus became higher with a 0%–10% increase in the mica content. The shear modulus of the unsaturated sand had a slightly higher degree of anisotropy than that of the saturated sand. In addition, the degree of anisotropy of the shear modulus was assessed based on the average orientation angle θof the sand particles.

Cohesive soils in nature are created under anisotropic stress and have various stress histories. Embankments generate greater vertical loads underground. Moreover, associated excavation activities can exacerbate the extensional stress state. This study investigated the effects of induced anisotropy on the shear modulus in saturated and unsaturated cohesive soils. A triaxial testing apparatus, equipped with local small strain (LSS) measurement devices and bender elements (BEs), was used to measure the small strain shear modulus. Two series of tests were conducted: (1) LSS and BE tests used specimens normally consolidated under a constant mean effective stress of p’=300 kPa or net mean stress pnet=300 kPa with different stress ratios to investigate the effects of anisotropic consolidation. The values of the applied stress ratios, represented as K= σ'h/ σ'vfor the saturated soil and Knet= (σh–ua)/(σv–ua) for the unsaturated soil, were 0.35, 0.43, 0.6, 0.8, 1.0, 1.5, 2.0, 3.0, and 3.5. (2) BE tests used specimens consolidated under various mean effective stresses in the order of p’=50, 100, 200, 300, 400, 500, and 600 kPa, and swollen in reverse order under Kof 0.35, 0.43, 0.6, and 1.0, to elucidate p’and the effects of the overconsolidation ratio (OCR). The results demonstrated that K-consolidation under constant p’produces large differences in initial shear modulus G0in saturated cohesive soil, but Knetproduces only slight differences in unsaturated cohesive soil because of the influence of strong matric suction. Finally, G0was normalized successfully considering the effects of void ratio e, K, and OCR.

The strain rate during shearing has been shown in experimental studies to strongly affect the mechanical behaviour of soil. For saturated soil, sufficient knowledge has been obtained to achieve equilibrium conditions for the pore water pressure. Nevertheless, little is known about unsaturated soil. Therefore, this study used a hollow cylindrical torsional shear apparatus to investigate the rate dependence on the deformation and strength properties of unsaturated soil. First, unsaturated specimens were anisotropically consolidated with different directions of major principal stress to assess the rate dependence of the anisotropic behaviour. Then, the shear stress was removed to produce an isotropic stress state. Shearing was applied using the specimens to evaluate the strain rate effects on the mechanical properties of unsaturated cohesive soil. The results indicate that the secant shear modulus increased with the strain rate in both constant suction (CS) and constant water content (CW) conditions. The shear strength did not change with the strain rate under a CW condition, but it decreased with the strain rate under a CS condition.

Liquefaction resistance is known to increase concomitantly with the increase in time after construction or sedimentation. Nevertheless, the mechanisms of its aging effect on liquefaction have not been completely elucidated. To clarify the mechanisms of aging in sandy soils, the liquefaction resistance (CRR), initial and secant shear moduli (G0and Gsec), and laboratory penetration resistance of long-term consolidated sand specimens were examined using cyclic undrained triaxial tests, local small strain (LSS) tests equipped with bender elements (BEs), and penetration index tests, respectively. Based on the existing reports, the CRR was inferred from G0, Gsec, and the laboratory penetration resistance. In the case of Toyoura sand of Dr=40%, the CRR increased by about 14% with a 360-day consolidated specimen in the cyclic undrained triaxial tests. However, increases in the CRR evaluated from G0and the laboratory penetration resistance were nothing and only 2%, respectively. Gsecstarted to degrade at greater shear strain in the long-term consolidated specimens. An increase in the CRR, evaluated from the Gsecof 0.01% shear strain, had a much better agreement with that obtained from the cyclic undrained triaxial tests.

Triaxial testing apparatus and procedures for unsaturated soils have become common along with the development of equipment and sensors. Although many drainage conditions are related to the pore-air and pore-water phase, the drained pore-air condition is usually adopted for tests of unsaturated soils. The main reason is that it is difficult to keep the pore-air undrained because the air diffuses easily through a rubber membrane. However, pore-air and pore-water are sometimes not allowed to drain under ground deformation problems. Therefore, undrained conditions in which pore-air and pore-water are not allowed to flow in and out of the soil are achieved in the experiments described herein. First, problems of a conventional triaxial apparatus for unsaturated soils were investigated to produce the undrained conditions. Then, triaxial testing methods under the undrained conditions were developed for overcoming the problems. Finally, the performance of the proposed testing procedure was demonstrated in comparison with results obtained using conventional testing.

A novel intermolecular alkenyl transfer of enamines was developed for the preparation of cycloalkenylaminomethyleneoxazolones, which were thermally cyclized to [ b]-fused pyridines in good yields. The functional manipulation of the pyridines provided versatile precursors for further annulation to tricyclic ring systems.

The JFT-2M computer complex system of the Japan Atomic Energy Research Institute (JAERI) consists of a data acquisition system and a plasma control system. The data acquisition system is composed of a CAMAC serial highway, a front-end minicomputer, a super-minicomputer and their peripherals. The system constitutes a definite hierarchical structure. This provides for easy expansion and maintenance as well as for improved RAS (reliability, availability and serviceability) functions and man-machine interface capabilities. The system permits unified control and high quality analysis of experimental data from the JFT-2M tokamak, processing 1.2 megabytes of data in less than 3 minutes. The plasma control system is made up of a pre-programmed minicomputer for current form pattern generation, an analog computer for high-speed plasma control, a local data logger, and thyristor power supplies. This system controls poloidal coil current by real-time feedback method. With a learning control function added to it, the system can effectively correct steady-state deviations.

Glucoamylase was immobilized by glutaraldehyde combined with albumin coated on the surface of a powder of SrFe2O4as the carrier. This carrier obtained a magnetically anisotropic property under exposure to a static magnetic field. The carrier was able to oscillate and rotate in an alternating magnetic field. The rate of hydrolysis of starch to glucose increased in the alternating magnetic field. This is because the transport of molecules may be facilitated through the interface of the carrier surface and solution by oscillation.

High quality Nb-based tunnel junctions with surface areas of 100 x 100 μm2and 200 x 200 μm2were tested by irradiating X-rays. According to the decrease in the disappearance of quasiparticles before tunneling, the 200 x 200 μm2junction exhibited better X-ray response than that of 100 x 100 μm2one. In the operation of the 200 x 200 μm2junction, two kinds of stable operation modes with different pulse heights were found by applying a magnetic field with different ramping speeds. The higher pulse height mode was observed with a ramping-speed faster than about 200 G/s. After tuning of the bias current in the higher mode operation, the energy required for single electron collection was obtained to be 6.5meV and the junction detected 5.9keV X-rays of 55Mn with an energy resolution (FWHM) of 93eV. The 200 x 200 μm2junction has the largest dimension among tunnel junctions exceeding silicon-semiconductor detectors in energy resolution.

Landslides triggered by near-field earthquakes with epicentres directly beneath towns have attracted intense attention since the 2004 Mid-Niigata (Niigata-ken Chuetsu) Earthquake. Hilly and mountainous areas sustained heavy damage. Social problems developed when many towns became isolated because landslides cut off traffic and public service lifelines. Soil from landslides closed river channels and formed natural dams. The natural dams submerged some towns. Emergency measures were undertaken promptly to prevent debris flows caused by natural dam breaks. Subsequently, the 2007 Mid-Niigata Offshore (Niigata-ken Chuetsu-oki) Earthquake and the 2011 Northern Nagano Earthquake struck the Niigata region. Landslides triggered by those earthquakes differed in terms of their number, scale, and location. Therefore, characteristics of the landslide sites of the respective earthquakes were examined to ascertain their topographical and geological features. Furthermore, differences in groundwater level and damage related to compound disasters were explained for discussion of the stability progress of damaged slopes.

The magnetic field dependence of the Josephson current of a Josephson tunnel junction whose shape was a normal distribution is analyzed for superconducting tunnel junction (STJ) photon detector applications. It was found that the Josephson current of a normal distribution junction is very sensitive to the external magnetic field and follows a function of exp (-B2), while a conventional rectangular STJ exhibits the well-known Fraunhofer pattern of sin x/x. Numerical calculations show that the Josephson current of the normal distribution junction can be suppressed by an external magnetic field that is one tenth of that needed for conventional rectangular junctions. Calculations of a normal distribution junction approximated with a 1 µm mesh also show that the Josephson current is sufficiently suppressed by a small magnetic field. The effect of the misalignment of the angle between the junction and the magnetic field was evaluated. It was found that for a normal-distribution-shaped junction, misalignment of the magnetic field is allowed within ± 5°, suppressing the Josephson effect by two orders of magnitude more than that of a rectangular junction.

We perform growth of thin Al films using the electron cyclotron resonance (ECR) technique on {100} Si wafer and bcc {110} Nb thin films at room temperature. The {110} Nb thin films are also prepared by means of ECR. We carry out depositions using Xe plasma gas. We analyse the surface structure of the films using reflection high-energy electron diffraction (RHEED) and atomic force microscopy (AFM). The analyses show that Al films are polycrystalline on both Nb and Si substrates. Moreover, very thin Al films on Nb show a remarkable match with Nb surfaces that in turn, exhibit epitaxial behaviour and atomic scale flatness. This results in a good coverage of the Nb base itself.

We have fabricated YBa2Cu3Ox(YBaCuO) crossover structures using CeO2films as insulating layers, varying the area from 10×50 to 50×50 µm2. The fabrication process of the crossover structure was performed ex situ, by combining the deposition of YBaCuO and CeO2films with the microfabrication of YBaCuO bridges and contact holes in the CeO2layer using a liquid-nitrogen-cooled dry etching method. Even though we used ex situprocesses, the bottom YBaCuO bridges had a transition temperature Tcof 87 K and a critical current density Jcof 1.0×105A/cm2at 77 K. Typical crossover resistivity was more than 2.0×108?·cm below 80 K even for 50×50 µm2structures. This indicates that CeO2is a promising material for insulating layers in high-Tcsuperconducting devices.

Niobium-based superconducting tunnel junctions are expected to be applicable to high-resolution X-ray measurements. Large-sized tunnel junctions with a Nb/Al/AlOx/Nb structure have been fabricated in order to study their performance in X-ray detection. The niobium layer which was sensitive to X-rays had a large size of 100 µm square ×1.2 µm thick. The junction detected 5.9 keV X-rays with an energy resolution of 1 keV. On the basis of the experimental data, the junction parameters were studied to produce a better energy resolution than that of silicon semiconductor detectors. The microstructure of the aluminum layer was observed by means of a transmission electron microscope.

The anisotropy in the magnetic penetration depth ? at 4.2 K has been systematically investigated with (103)-oriented YBa2Cu3O7-xthin films, using the resonator technique in transmission lines. The obtained values are ?=1.4±0.4 µm and ?=400±130 nm for the current flow across and parallel to Cu-O planes, respectively. This anisotropy ratio is in good agreement with the value estimated from the anisotropic resistivities of the films.

High quality Nb-based tunnel junctions with surface areas of 100×100 µm2and 200×200 µm2were tested by irradiating x-rays. The 200×200 µm2junction exhibited better x-ray response than that of the 100×100 µm2one, due to better collection of quasiparticles. The junction detected 5.9-keV x-rays with an energy resolution (FWHM) of 93 eV and the energy required for single electron collection was 6.5 meV. In the operation of the 200×200 µm2junction, two kinds of operation modes with different pulse heights were found by applying a magnetic field with different ramping speeds. The individual operation modes gave different current-voltage characteristics. The Sine-Gordon equation was employed to calculate the current-volt-age characteristics for the large junction. From calculated results, it was confirmed that the higher pulse height operation mode was related to a large reduction of dc current through the junction.

High quality Nb/AlOx/Nb superconducting tunnel junctions (STJs) are fabricated for the radiation detection. The fabrication process includes a MgO thin film, an underlayer method, a control of critical current, a nitrogen plasma passivation, and a SiO2insulating layer. Subgap current characteristics of STJs have been investigated in the temperature range of 0.35K to 4.2K in order to evaluate the junction quality for the radiation detection. The STJs fabricated by present process show extremely high quality junction characteristics with a leakage current density of 0.1 pA/µm2, a resistance ratio Rd/Rnof 6×106for a 200×200-µm2STJ with a critical current density of 200A/cm2.

Superconducting Tunnel Junctions are promising devices in next generation nuclear and optical detectors. Unfortunately, a number of relaxation processes in the number of initially produced excitations degrades the performances of such devices. In order to investigate the role of charge loss mechanisms in Nb and/or at the Nb/Si interface we have fabricated three terminal in-planedouble tunnel junctions, in which quasi-particles are injected into a Nb common strip and detected at different distances by tunnel junctions. The detection efficiency ? decreases of about one order of magnitude from T=4.2K to T=1.2K for any injector-detector distance. The presence of charge trapping centers, activated at low temperatures, can qualitatively explain such a result. The estimation of the quasi-particle diffusion constant D=28±5 cm2/s at T=1.2 K is in agreement with other similar values reported in literature.

Nb/Al-AlOx/Nb superconducting tunnel junctions (STJ's) designed for X-ray detection have been fabricated. The behavior of the low-temperature subgap leakage current, which severely limits the energy resolution obtained in such devices, is investigated. From trends in the dependence of the leakage currents on the critical current density and the size of the STJ, as well as from the low-temperature current-voltage characteristics, and an analysis of the base electrode surface morphology, it is concluded that physical defects in the barrier region are the most probable cause of the leakage currents. Suggestions are given for optimization of the device processing.

A novel optical imaging method by using a memory-correlator in which a laser pulse acts to store wideband surface wave signals in surface states of a semiconductor is described. The Fourier transform technique is used to scan optical images by storing a chirp surface wave signal and an optical pattern simultaneously, which can improve a dynamic range and a signal-to-noise ratio in comparison with a single scan pulse method.

A new fabrication process is presented to make Nb/Al/AlOx/Nb superconducting tunnel junctions with ultralow subgap leakage current at low temperatures below 4.2 K for X-ray detection. A Nb anodization process has been adopted to make electric insulation at the periphery of an ultrathin AlOxtunnel barrier through use in combination with the conventional SiO self-aligned insulation process. The temperature dependence of the subgap current of the junctions fabricated by the present process is in good agreement with that predicted by the Bardeen-Cooper-Schrieffer (BCS) theory, while junctions made by the conventional process show a weak temperature dependence of the subgap current. In addition, the Vmvalue of the junction fabricated by the present process was found to be more than 3000 mV at 1.2 K. It has been clarified that the anodization process introduces improvements to make the subgap leakage current extremely small in the temperature range from 4.2 K down to 1.2 K.

A Josephson logic gate which consists of a closed loop with four Josephson junctions (4JL gate) and its operating characteristics are described. Devices have been fabricated using Pb-alloy technology with a minimum line-width of 5 µm. Gate operations with a current gain of 2 have been performed under complete input/output current isolation. A logic delay of 20 ps per gate has been measured in a chain of ten OR-gates for a fan-out of 1 with an average power dissipation of 3.7 µW.

A new dry etching method has been developed for patterning YBaCuO thin films with less damage, wherein samples are cooled by liquid nitrogen. It is found that the critical current density Jcof films etched by this cooling method is significantly improved, more than one order of magnitude higher than that for the films etched at 5°C. Furthermore, it is found that this technique causes less damage to the surface of the YBaCuO films, compared to the etching at 5°C. This result suggests that the dry etching process with liquid nitrogen cooling is a promising method for the fabrication of high-Tcsuperconducting electronic devices of small dimensions.

Palladium thin-film resistors have been systematically investigated for Josephson LSI circuits. It has been found that the sheet resistance of the palladium was strongly affected by the deposition rate. By the introduction of precise control for the deposition rate using an electron-beam gun, the palladium thin-film resistors have been successfully integrated on the chips with a resistance variation of less than ±2% as is required for fabrication runs.

A new fabrication process of small Nb/Al-oxide/Nb tunnel junctions for integrated circuits is presented. Prior to making tunnel junctions of Nb/Al-oxide/Nb sandwich structure with a full wafer size, an Nb electrode layer was prepared on the wafer, whose patterns were duplicated from each junction base electrode pattern. This additional underlayer of Nb plays an important role in improving I-V characteristics, especially in the small size Nb/Al-oxide/Nb junctions. A reactive ion etching process was employed to define each junction size precisely. Using the present process, Vm=40 mV and Rsg/Rnn=26 with a critical current density of 1000A/cm2have been achieved in an one-hundred 2.5 µm square junction array.

Characteristics of the NbN/MgO/NbN Josephson junction for integrated circuits have been investigated. The deposition process of the MgO film for the tunnel barrier was systematically investigated to obtain the controllability of the Josephson critical current density. The reproducibility of the Josephson critical current density was improved to ±28% with the critical current density of 610 A/cm2and ±20% with the critical current density of 16 kA/cm2. The uniformity of the Josephson critical current density across a 3 cm-square area on the substrate was improved to ±12% with the critical current density of 650 A/cm2.

Josephson tunnel junctions with all niobium nitride (NbN) electrodes were fabricated with sputtered amorphous silicon (a-Si:H) films as tunnel barriers whose surfaces are oxidized by an rf-plasma oxidation. The specific capacitance of the fabricated junction strongly decreased with increase in the thickness of the a-Si:H film. The specific capacitance of less than 4 µF/cm2was obtained for the a-Si:H thickness of about 2 nm. A logic circuit composed of four-junction logic (4JL) gates was fabricated using these junctions and was operated with the minimum logic delay of 9 ps/gate.

A new timed inverter with a simple structure and a wide operating margin has been developed. It is composed of a 4JL gate with a single limiting junction connected to the input terminal of the gate. The threshold characteristics and operating sequences have been investigated theoretically. Successful logic operation of the inverter has been performed with an operating margin of ±33% against both input and timing signals.

Sub-10 ps logic delays have been obtained in a Josephson four junction logic (4JL) gate. An experimental circuit including a logic chain of ten 4JL gates whose minimum junction size is 2.5 µm square has been fabricated using a Pb-alloy integration technology. The shortest switching delay has been measured to be 7 ps/gate for the fanout of 1 with a power dissipation of 4 µW/gate.

A fabrication technology of NbN/Pb Josephson tunnel junctions has been developed by using a new microfabrication technique. The Josephson characteristics of NbN/Pb tunnel junctions formed on rf reactive sputtered NbN films are reported. The junctions are found to have large gaps (?NbN+?Pb=3.8 mV), low leakage, and to be quite stable with respect to thermal cyclings and storage at room temperature.

A storage of phase and amplitude (holographic storage) of surface acoustic waves has been realized in an Al/ZnO/SiO2/Si monolithic structure. An injection of electrons from Al into ZnO is utilized to form the charge grating with the periodicity equal to the wavelength of the surface wave. This pattern is stored in trapping centers in ZnO resulting in the storage time longer than 10 h.

A new method for storing both phase and amplitude of surface wave signals with large bandwidth in silicon surface states by a short light pulse emitted from a GaAs laser diode is presented. 87 MHz surface wave signals are stored by using a light pulse with a duration of 0.5 ns and the stored signal are read out as a correlation output signal at a delayed time after storage. Pulse compression experiments are also demonstrated by storing a linear FM chirp signal with this method.

Flip-chip bonding using superconducting solder bumps consists of two technologies: acid-free thermosonic compression ball bonding and face-down bonding of the chip on the substrate by means of thermosonic compression at 373 K. A superconducting test chip with 68 bumps formed on Nb/Pd film pads was bonded on a ceramic substrate. The maximum shear strength of a single solder bump for the Nb/Pd films was found to be 26.5 MPa, which was about 3 times higher than that obtained for Nb/Au film pads. The flip-chip module did not undergo catastrophic failures in either prototype design or material combination during 20 thermal cyclings between 4.2 K and 273 K. Electrical check tests at 4.2 K before and after the thermal cyclings suggest that the present superconducting solder bump can be put into practical use for superconducting IC chip connection.

Nb/polyimide stacked layers on a multilayer ceramic substrate makes it possible to fabricate superconducting off-chip wiring for control signal lines. This superconducting multichip module (SuperMCM) also provides matching circuits for the clock signal and DC bias circuits beneath the superconducting transmission lines. The first prototype SuperMCM in the world successfully made,which has been designed to drive Josephson LSI chips at the highest clock frequency of 1.2 GHz.

A novel current switching Josephson logic gate in which four junctions are connected in a loop is described. This four-junction logic gate can reduce an inductance included in the loop as small as possible, so that the higher switching speed and the smaller device size is expected. The switching threshold and the switching characteristics of the gate are investigated both theoretically and experimentally. Logic circuits based on the gates are also experimentally demonstrated.

Series arrays of 1440 Josephson tunnel junctions were fabricated out of Nb/AN-oxide/Nb- and Nb/NbN/MgO/NbN/Nb-sandwiches The arrays provide microwave-induced constant voltage steps of at least one volt. The good stability of hard superconductor tunnel junctions against room temperature storage and thermal cyling suggests that these arrays might be very useful for the constructions of practical lasting Josephson voltage standards of high precision.

A full adder Josephson circuit consisting of direct-coupled four-junction logic gates (4JL gate) has been designed and fabricated by a 5 µm lead-alloy junction technology. Carry signal is generated by the combination of two-input OR- and AND-gates, and sum signal is generated by two exclusive-OR gates connected with a four switching gates chain to obtain a delayed timing signal. The circuit of 21 gates has been found to be quite stable for add opeations at a total power current level of 3.5 mA±0.23 mA with a total power dissipation of 42 µW. By dynamic simulations of the circuit, carry and sum logic times are evaluated to be about 70 ps and 220 ps, respectively.

We have fabricated Josephson junctions consisting of all (103)-oriented YBaCuO/PrBaCuO/YBaCuO trilayer films, varying the thickness of the PrBaCuO barrier from 45 to 100 nm and the junction area from 10×10 to 50×50 µm2. A scaling behavior with critical current× normal resistance ( IcRnproducts) proportional to (critical current density Jc)1/2is observed for fabricated trilayer junctions. Furthermore, it is found that junctions with trilayer and edge structures reported by other groups also obey this scaling behavior, strongly suggesting that the junction properties can be determined by the lowered value of the order parameter at the interface between the YBaCuO film and barrier layer, due to the proximity effect within the framework of the short-coherence-length effect.