Design and processing of high-density single-mode fiber arrays for imaging and parallel interferometer applications

The design and fabrication procedures for implementing a high-density (16-microm center spacing) single-mode fiber (SMF) array are described. The specific application for this array is a parallel optical coherence tomography system for endoscopic imaging. We obtained fiber elements by etching standard single-mode SMF-28 fibers to a diameter of 14-15 microm. We equalized 1-m lengths of fiber to within 1 mm by using a fiber interferometer setup, and we describe a method for packaging arrays with as many as 100 fibers.     

Czochralski growth of Yb doped oxyapatite for high power laser application

Ca₈(La,Yb)₂(PO₄)₆O₂ (Yb:CLPA) single crystals with the apatite-type structure could be grown from the melt using the Czochralski method. Grown crystal was 18 mm in diameter and 110 mm in length. It is transparent with slightly blue color. Neither visible inclusion nor crack was observed. Thermal conductivity of Yb:CLPA was calculated from the values of thermal diffusivity, heat capacity measurement and density. Luminescent characterization was carried out from the results of emission, absorption and Raman spectrum.     

Seismic Performance of a River Dike Improved by Sand Compaction Piles

Sand compaction piling is one of the commonly used countermeasures for earthquake liquefaction hazard of river dikes. This paper presents a case study of the performance of an instrumented dike in northeast Japan that was improved by sand compaction piles and subjected to the 2003 Northern Miyagi Earthquake, with the aim to better understand the effectiveness of this ground improvement method. Simulation has been carried out by means of a fully coupled numerical procedure which employs a sophisticated cyclic elastoplastic constitutive model and the updated Lagrangian algorithm. Comparisons between the field measurements and the computed responses, including the time histories of accelerations and pore-water pressures at different locations, show reasonably good agreement. Numerical simulation has also been made of the same dike but without ground improvement to identify the effects of sand compaction piles in altering the performance of the dike. The study demonstrates that the comprehensive numerical procedure is a promising tool for development of seismic performance-based design of earth structures.     

Motivational bases of the public goods problem.

Compared 2 motivational bases for not contributing to a public good, desire to "free ride" (or greed) and fear of being a "sucker," among 110 Japanese undergraduates. It was hypothesized that these 2 types of motivation would be activated under different situations. When a public good was provided conjunctively, fear would have a strong effect but greed would not; when a public good was disjunctively provided, greed would have a strong effect but fear would not. In addition, it was predicted that the greater mutual trust existing among friends would make them contribute more than strangers would in the conjunctive condition but would make no difference in the disjunctive condition. Three types of production rules, in which a public good was conjunctively, disjunctively, or additively produced on the basis of members' contributions, were experimentally created. Half of the groups in each condition consisted of total strangers, and the other half consisted of friends. The hypotheses were supported when the size of the public good (bonus points) was relatively large. Also, Ss responded similarly in the conjunctive condition and in the additive condition. (25 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Deoxidation of Ti Melt by Newly Developed Two-Step Plasma Arc Melting Process Using Hydrogen

Metallurgical and Materials Transactions B - A two-step plasma arc melting process, comprising a first step under Ar-30 pct H2 gas flow and the second step under Ar gas flow, has been...     

Effects of boron on the creep properties,phosphorus segregation behaviour,and stress relief cracking susceptibility of 1.5% Cr–0.5% Mo steels

The effects of 25 ppm boron and of 0.05% phosphorus on the creep behaviour at 550 °C and on the fracture temperature in the constant load fracture test were tested for a 1.5% Cr–0.5% Mo steel. B and P decrease the creep strength, the rupture elongation is increased by B. B and P lower stress relief cracking susceptibility, however, it is increased at low stress. In the B doped material the rate of P grain boundary segregation is accelerated and the level of equilibrium segregation is somewhat higher, the equilibrium segregation is somewhat lower in the bainitic than in the martensitic structure.     

Grain refining of Al-4.5Cu alloy by adding an Al-30TiC master alloy

A particulate Al-30 wt pct TiC composite was employed as a grain refiner for the Al-4.5 wt pct Cu alloy. The composite contains submicron TiC particles. The addition of the TiC grain refiner to the metal alloy in the amount of 0.1 Ti wt pct effected a remarkable reduction in the average grain size in Al-4.5 wt pct Cu alloy castings. With the content of over 0.2 Ti wt pct, the grain refiner maintained its refining effectiveness even after a 3600-second holding time at 973 K. The TiC particles in the resulting castings were free of interfacial phases. It is concluded that the TiC are the nucleating agents and that they are resistant to the “fading effect” encountered with most grain refiners.     

Video-assisted thoracoscopy in single-stage resection of a para-aortic posterior mediastinal dumbbell tumor

The incidence of cystic fibrosis (CF) has previously been calculated from epidemiological surveys and from neonatal screening. With the cloning of the CF gene it has become possible to derive incidence figures from heterozygote frequencies, provided that the distribution of mutant alleles among healthy carriers is the same as among affected people. We have estimated the allele frequencies for four CF mutations, AF508, G551D, G542X and R117H, in 14360 unselected women undergoing antenatal heterozygote screening. The proportion of R117H, an allele of known mild effect, was much greater for heterozygotes than for homozygotes. The incidence of CF was therefore calculated from the heterozygote frequencies of AF508, G551D and G542X in a larger cohort of 27 161 successively screened women. The point estimate for the incidence of CF in the Scottish population was 1 in 1984, with 95% confidence intervals of 1 in 1692 to 1 in 2336.