Optical circulator consisting of a YIG spherical lens, PANDA-fibre polarisers and a fibre-optic polarising beam splitter

A novel optical circulator is reported which employs an yttrium-iron-garnet (YIG) sphere, PANDA-fibre polarisers and a fibre-optic polarising beam splitter. The splitting ratios of the fibre-optic polarising beam splitter were 1.0:99.0 for x-polarisation and 97.5:2.5 for y-polarisation, with an excess loss of 0.5 dB at 1.30 ?m wavelength. The backward isolation of the optical circulator was 30 dB with the total insertion loss of 4.5 dB.     

Effects of Particle Size of Bulk Drug and food on the Bioavailability of U-78875 in Dogs

The effects of particle size and food on the absolute bioavailability of U-78875 in dogs after oral administration of either a suspension or tablet dosage form were investigated. A reduction of particle size caused a significant increase in bioavailability along with an increase in dissolution rate. Additionally, both suspension and tablet dosage forms administered after food caused an increase in bioavailability. Thus, to accelerate drug dissolution, a reduction of U-78875 particle size from the unmilled state is important for the optimization of formulation compositions. To increase the bioavailability of U-78875, postprandial dosing should be considered.     

ELEVATED AND ROOM TEMPERATURE MECHANICAL BEHAVIOR OF BORON DOPED NiAl ALLOYS

The effects of boron addition on defect hardening at room temperature and on high temperatrue creep properties are investigated in the B_2 NiAl intermetallic comopound.It is foundthat boron addition is effective on inereasing the room temperature hardeness on theNi-rich side but it has no effect on the Al rich side of stoichiometry.These obseryationsare attributed to interstitial dissolution of boron in Ni-rich NiAl and to a lack of solubilityand also due to an enrichment at grain boundaries on the Al-rich side.The similar effect is found in high temperature creep resistance of NiAl by bofom addition.The high temperature creep resistance increases on the Ni-rich side but it does not affect the Al-rich side ofoff-stoiciometry.     

Polarisation-maintaining fibre couplers with low excess loss

Polarisation-maintaining fused fibre couplers with excess loss of less than 0.1 dB have been fabricated by using polarisation-maintaining and absorption-reducing (PANDA) fibres with matched-index stress-applying parts. The couplers show polarisation crosstalk of less than ?30 dB.     

Study on the hydrothermal drying technology of sewage sludge

Drying of sewage sludge is an effective way for treatment and utilization of sewage sludge,where reduction of energy consumption is one of the major technical challenges.So we experimentally investigated the possibility of the hydrothermal treatment.We have found that treatment of sewage sludge by saturated steam with the temperature of 190°C and pressure of 20 bar can dramatically improve the dehydration performance of the slurry like product.And the water content can be reduced down to about 55% by a mech...     

Growth and photoreactive properties of a- and c-axis cerium-doped strontium barium niobate single-crystal fibers

The authors report on the photorefractive properties of cerium-doped strontium barium niobate (Ce:SBN60) single-crystal fibers grown by the laser-heated pedestal growth method. Single-crystal fibers, 250 mu m in diameter, were successfully grown along both the a- and c-axes. The diffraction efficiency and grating formation time results for each fiber in two beam coupling experiments are compared, with emphasis on their crystal orientation and relevant figure of merit. It is found that the hologram efficiency of the a-axis fiber is larger than that of the c-axis fiber and that its grating formation time is faster. The results suggest that Ce-doped SBN single-crystal fiber grown along the a-axis is a promising candidates for holographic storage, parallel data processing, and phase-conjugation mirrors.<>     

Polarising fibre coupler with high extinction ratio

Fused polarising fibre couplers have been fabricated using single-polarisation single-mode fibres. When circularly polarised light is fed into the coupler, one of the two orthogonal polarisation modes suffers strong attenuation, and only one polarisation mode couples in the fused biconical taper region. The extinction ratio of the coupler is 41 dB at a wavelength ? = 1.3 ?m with a coupling ratio of 48:52.     

Effects of diffuser shape and back pressure on the performance of disk MHD generators

The effects of diffuser shape and back pressure on the performance of closed‐cycle disk MHD generators are investigated with two‐dimensional numerical simulations taking account of the boundary layer. The enthalpy extraction ratio decreases and fluctuates periodically with increase in the back pressure. The amplitude of power output fluctuation and the period depend on the volume of the inverse flow region. For the reduced height diffuser, the inverse flow region is suppressed and the fluctuation becomes smaller than that for the constant height diffuser. When operated with a back pressure lower than an optimum value, the diffuser does not work because of reacceleration in the diffuser. For the higher back pressure, on the contrary, the inverse flow region propagates into the MHD channel, then the enthalpy extraction ratio is reduced and the Mach number at the exit of the MHD channel becomes lower than unity. For the optimum back pressure, high enthalpy extraction ratio is achieved and the adiabatic efficiency at the diffuser exit is decreased by several percent from that evaluated at the MHD channel exit. © 2000 Scripta Technica, Electr Eng Jpn, 133(2): 11–19, 2000