Dynamic behavior of bubble domains at low drive field

Dynamic properties of bubble domains at low drive pulse field are examined by the bubble transport method. Important findings are as follows. 1) The bubble does not move unless the pulse duration exceeds a critical value which depends on the pulse amplitude. 2) A minimum pulse amplitude is also required for the bubble translation which depends on the pulse duration. 3) As the pulse duration goes to infinity, the minimum drive field approaches a constant value which is different from the dynamic coercivity. 4) As soon as the pulse duration exceeds the critical value, the bubble is displaced discontinuously by a finite distance independent of the drive field. All of these properties are adequately explained by a simple phenomenological theory, in which the domain wall is assumed to be connected by springs to pinning sites until the wall is displaced by a finite distance.     

First-principles calculation of phase equilibria and phase separation of the Fe-Ni alloy system

Theoretical investigation of the phase equilibria of the Fe-Ni alloy has been performed by combining the FLAPW total energy calculations and the Cluster Variation Method through the Cluster Expansion Method. The calculations have proved the stabilization of the LIE phase at 1：3 stoichiometry, which is in agreement with the experimental result, and predicted the existence of L1 0 as a stable phase below 550 K; this L1 0 phase has been missing in the conventional phase diagram. The calculations are extended to the Fe-rich region that is characterized by a wide range phase separation and has drawn considerable attention because of the intriguing Invar property associated with a Fe concentration of 65%. To reveal the origin of the phase separation, a P-V curve in an entire concentration range is derived by the second derivative of free energy functional of the disordered phase with respect to the volume. The calculation confirmed that the phase separation is caused by the breakdown of the mechanical-stability criterion. The newly calculated phase separation line combined with the L1 0 and L12Eorder-disordered phase boundaries provides phase equilibria in the wider concentration range of the system. Furthermore, a coefficient of thermal expansion （CTE） is attempted by incorporating the thermal vibration effect through harmonic approximation of the Debye-Gruneisen model. The Invar behavior has been reproduced, and the origin of this anomalous volume change has been discussed.     

Investigation of shrinkage and cracking of ophthalmic lens coating by a cycle test of UV radiation and high humidity

This paper presents some ophthalmic lens coating failures such as shrinkage, cracking, and cracking with delamination caused by UV radiation, elevated temperature, and moisture. These phenomena are caused by: 1) interactions at the interface between the plastic substrate and the hard coating (HC), and 2) plastic deformation with stress and relaxation of the HC/substrate interface. This phenomenon leads to an understanding of the mechanical properties of ophthalmic lenses through a QUV test which is found to be a useful method in developing better ophthalmic lens systems. The coating failures were investigated by means of different analysis techniques including optical microscope, scanning electron microscope, atomic force microscope, thermo mechanical analysis, and dynamic secondary ion mass spectrometry.     

Tomakomai Large Scale Crude Oil Fire Experiments

This paper summarizes the results of large-scale crude oil fire experiments conducted in Tomakomai, Japan, in 1998 to obtain information that could be applied to the development of firefighting strategies for, and the design of, huge petroleum storages. Arabian light-equivalent crude oil was burned in pans 5-, 10-, and 20-m in diameter. Most of the experiments were performed under favorable conditions. Measured data include external radiation, infrared image of the flame, flame temperature, gas concentration inside the flame, and other burning characteristics. The height of the strongest radiant emittance was H/D=0.1 to 0.2, where D=pan diameter and H=height from the initial fuel surface, and a kind of fireball appeared occasionally at the intermittant flame zone. Emitted smoke particles were sampled on the ground and observed with a scanning electron micrograph, and the distribution of the diameters of primary smoke particles was examined. The average diameter of primary smoke particles is 53.0 (±10.5)nm. The dependence of burning characteristics and flame structure on pan diameter is discussed. The flame height of the 20-m diameter pan fire is 1.9 (±0.3) D. The burning rate increases as the pan diameters increase, but the radiative fraction decreases as pan diameter increases.     

Gradually intractable problems and nondeterministic log-space lower bounds

The paper places five different problems (thek-pebble game problem, two problems aboutk finite automata, the reachability problem for Petri nets withk tokens, and the teachability problem for graphs whose k-dimensional edge sets are described by Cartesian products ofk factors) into the hierarchyNL _k of problems solvable by nondeterministic Turing machines ink-log₂ n space (and binary tape alphabet, to avoid tape speed-up). The results, when combined with the conjecture thatNL _i contains problems that requireO(n ^k ) deterministic time, show that these problems, while inP for every fixed value ofk, have polynomial deterministic time complexities with the degree of the polynomial growing linearly with the parameterk, and hence are, in this sense, gradually intractable.     

Channelling studies on the lattice location of B atoms in graphite

In order to obtain information on the lattice location of B atoms in graphite, channelling experiments have been performed at room temperature with a proton beam of an energy of 0.65-0.77 MeV for the 〈0 0 0 1〉 axial channel in highly oriented pyrolytic graphite (HOPG) crystals doped with 0.32 at.% B. The B atoms are detected by measuring α-particles which are emitted as a result of a nuclear reaction ¹¹B(p,α)αα. It is clearly demonstrated that most of B atoms are shadowed behind the 〈0 0 0 1〉 C atomic rows. Taking account of the already reported experimental results on a change of lattice parameters by B-doping, it is concluded that most of B atoms are located at substitutional sites. It is also observed that B-doping introduces lattice strain on the c-plane. In addition, the presence of a small portion of interstitial B atoms is suggested.     

Preparation and properties of carbon dental implant with fine rahmen surface layer

Blade- and tooth-root-form carbon dental implants were prepared by fixing fine Rahmen surface (FRS) layers of carbon fabric on a carbon fiber-reinforced carbon (CFRC) core. The fixing was successfully performed through the low-temperature deposition of pyrolytic carbon using cis-1,2-dichloroethylene as the raw material. The resultant implants showed flexural and compressive strength more than 150 and 100 MPa, respectively. The outer part of this FRS layer contained many pores ranging from 30 to 300 μm in diameter and 40–75% in volume fraction.New bone was generated in the open pores after being embedded in the femur of a monkey for 6 months. The shear strength of the embedded implant vs bone interface was 15 MPa. On the other hand, the blade-form FRS implant in the mandible of a monkey gave a locking system consisting of “bone-collagen fiber-calcified layer” after two years under a masticating pressure. The latter is very similar to the natural tooth system.     

Synthesis and characterization of dextrin derivatives by heterogeneous esterification

A series of fully-acylated dextrin esters (DS = 3) with varying side-chain lengths (C2–12) were synthesized by heterogeneous esterification using trifluoroacetic anhydride/carboxylic acid. The influence of side-chain lengths on structure and properties of dextrin esters were investigated by structural, thermal, mechanical and hydrophobic analysis. The thermal stability of dextrin was enhanced by esterification, presenting ca. 40–60 °C higher decomposition temperatures than that of neat-dextrin. The transition temperatures of melting and crystallization were not observed for all dextrin esters because they were amorphous polymers. The glass transition temperature (T_g) was not observed in dextrin but was observed in dextrin esters. As increasing side-chain length, T_gs of dextrin esters decreased ranged from 162.2 °C (C2) to 49.2 °C (C12). Colorless and transparent dextrin ester films were prepared to measure the film properties. Tensile strength of dextrin ester films tended to decrease with increasing side-chain lengths, whereas the elongation at break increased. And, dextrin ester films showed significantly increased hydrophobicity with a contact angle of up to 102° (C12).     

Dermal application of lisuride on parkinsonism induced by 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in the common marmoset and on cases with Parkinson''s disease

BACKGROUND: Follow-up study of patients with surgical repair of aneurysmal subarachnoidal hemorrhage (SAH), looking for clinical outcome predictors. PATIENTS AND METHODS: Sixty two patients consecutively admitted to a teaching hospital, from January 1992 to December 1995 were included in the study. We studied preoperative, intraoperative and postoperative features looking for their relationship with the outcome. The ultimate outcome was evaluated by means of Glasgow Outcome Scale on discharge and 6 months later. RESULTS: Smoking (p = 0.0001) and arterial hypertension (AHT) (p = 0.0186) were more frequent in these patients than in general population, but without relationship to the outcome as with the age of the clinical status on admission. The greatest statistical relationship was found between the level of consciousness on postoperative awakening (measured by the Hunt and Hess scale), and the outcome (p = 2.53 x 10(-8). From our results we made an algorithm that correctly assigned 92% of studied patients to their outcome. CONCLUSIONS: All patients admitted on with aneurysm SAH deserve intensive care treatment besides their clinical grade. The level of consciousness on postoperative awakening was a good outcome predictor.     

Pressure Rise and Propagation Phenomena Due to Fault Arc in Container with Opened Pipe

This paper describes experimental and analytic studies on pressure rise and propagation phenomena due to high current arcs in a container with opened pipes. The shape of the experimental container was chosen taking into account underground common ducts. First, arcs were ignited in the container with varying diameter D and length L of the opened pipes and at arc currents of 4 kA to 12.5 kA and an arc duration of 0.1 s. Based on measured waveforms, the maximum pressure rise and the pressure oscillation frequency were obtained. It was found that there is a tendency for to increase with decreasing D and increasing L, and that D has a much greater impact on . In addition, the tendencies of with changing D and L can be approximately explained by Helmholtz resonance. Second, a CFD model for the container with opened pipe was developed based on the experimental results, and simulations were performed. The simulation results were found to correspond to the experimental pressure rise.