POSSIBLE PRIMARY MIGRATION OF OIL GLOBULES1

Difficulty of migrating a large amount of oil in either molecular or micellar solution may lead to an assumption that a continous oil phase or a relatively high (20–30%) concentration of oil in pores of shales is necessary for primary migration to overcome the capillary restrictions against the oil. Movement of small oil globules in shales is believed by many workers to be an extremely difficult process. However, the above assumption is not necessarilly valid in shales which contain a large quantity of structured and semi-solid water. Such oil globules may defrom by the effect of compacting grains (solid material) and the semi-solid water, thus reducing the capillary restrictions significantly. This suggests that the small oil globules which are separated from each other can move in the direction of lower stress in the shales: a continous oil phase or relatively high oil concentration is not a necessary requirement for primary oil migration.     

Weak localization of photons: contributions from the different scattering pathlengths

Using time-resolved techniques, the contribution from different scattering pathlengths to the coherent peak of backscattered light from a random medium was directly observed. Using a 30-fs pulse laser and a three-dimensional streak camera, the width of the coherent peak is found to be broader for backscattered light traveling through shorter distances, while the width decreases for the light scattered through longer paths.<>     

Injection locking and synchronization of periodic and chaotic signals in semiconductor lasers

We experimentally investigate the synchronous response of a semiconductor laser to the injection of a periodic or chaotic oscillating optical signal that is generated by a similar semiconductor laser with optical feedback. We show that there are two different types of synchronous response, appearing in separate regimes of laser frequency detuning and injection strength. They are distinguished by the time lag of the slave-laser response with respect to the injection signal from the output of the master laser. The experimental observations are well described by a numerical model consisting of a set of rate equations. It is revealed that the first type of synchronous response corresponds to the complete synchronization solution of the equations and the second type of response is the result of strong driving. The relevance of these two types of synchronous behavior to a number of recent experiments on chaos synchronization and their implications for data encoding/recovery using chaotic carriers are discussed.     

Effect of hexafluoropropylene on the performance of poly(vinylidene fluoride) polymer actuators based on single-walled carbon nanotube–ionic liquid gel

The effects of polymer species (poly(vinylidene fluoride)) (PVdF) homopolymer or poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF(HFP) copolymer), average molecular weight of the polymer, and the HFP content in PVdF(HFP) on the electrochemical and electromechanical properties of actuators using polymer-supported single-walled carbon nanotube (SWCNT)–ionic liquid (IL) gel electrodes were investigated. For the PVdF (Kynar 741 or 761) actuator containing 1-ethyl-3-methylimidazolium tetrafluoroborate (EMI[BF₄]), the generated strain was 0.90–1.05% for the frequency range of 0.01–0.005 Hz, which was over twice as large as that for the PVdF(HFP) (Kynar Flex 2801) actuator. Furthermore, it is considered that the HFP content should be low (or zero) for large generated strain and zero for large maximum stress. The PVdF actuator performs much better than the PVdF(HFP) actuator and has a quick response, sufficient for practical application (e.g., tactile displays).     

Eye-opening improved electroabsorption modulator/DFB laser diodewith optimized thickness of the separate-confinement heterostructurelayers

The separate-confinement heterostructure (SCH) of an electroabsorption modulator integrated with a distributed feedback laser diode (EAM-LD) was optimized to obtain a clear optical waveform (eye opening) without penalty of chirp characteristics. The electric field applied to the multiple-quantum-well (MQW) structure was controlled by employing the proper thickness of undoped SCH layers to attain gentle absorption characteristics of the EAM at the optical mark level. As a result, the eye opening of the modulated emission at 10 Gb/s was improved and the intersymbol interference was reduced. No severe drawback on chirp characteristics was found in an α-parameter measurement. EAM-LD's with the optimized SCH structure exhibited good transmission characteristics of power penalties under 1.5 dB at 10 Gb/s, and the reliability of 10 Gb/s transmission characteristics was also confirmed. We have also investigated how the optical waveform after transmission was affected by the dependence of the α-parameter on bias voltage. Measurement and numerical calculation of the optical waveform after transmission showed that the optical waveform was severely affected by the α-parameters at deep reverse voltages     

Seismic proof test of a reinforced concrete containment vessel (RCCV): Part 1: Test model and pressure test

In Japan, the Nuclear Power Engineering Corporation (NUPEC), sponsored by the Ministry of Economy, Trade and Industry (METI), has been conducting a series of seismic reliability proving tests using full-scale or close to full-scale models to simulate actual important equipment that is critical for seismic safety of nuclear power plants. The tests are intended to validate the seismic design and reliability with a sufficient margin even under destructive earthquakes. A series of tests was carried out on a reinforced concrete containment vessel (RCCV) for advanced boiling water reactor (ABWR) from 1992 to 1999. A large-scale high-performance shaking table at Tadotsu Engineering Laboratory, the largest in the world, was used for this test. Part 1 reports the test model and the results of pressure and leak tests. Part 2 describes test procedures, input waves and the results of verification tests such as changes of stiffness, characteristic frequency and damping ratio, the failure of the model and the load deflection. Part 3 shows the seismic safety margin that was evaluated from the energy input during the failure test to a design basis earthquake. Part 4 reports simulation analysis results by a stick model with lumped masses.     

Inflammatory bronchial polyps with a foreign body-like substance

A 68-year-old male complaining of hemosputum was admitted to our hospital. Fiberoptic bronchoscopic examinations revealed bronchial polyps and a flat foreign body-like substance in the left main bronchus. A closer inspection of a biopsied bronchial inflammatory polyp showed inflammatory edema with hypervascularization in the submucosal space and inflammatory cell infiltration. Following complete removal of this foreign body-like substance, the polyps disappeared within six weeks. It is therefore feasible to assume that the polyps appeared as a reaction to this extrinsic substance. The origin of the foreign matter is not obvious because the patient had no history of aspiration and because the histological examination did not confirm that it was a foreign body. The substance could have been formed out of the organization and calcification of some secretes in the bronchus.