Optical low coherence reflectometer with a 47-dB dynamic rangeachieved by using a fluoride-based erbium-doped fiber amplifier

We describe a jaggedness-free optical low coherence reflectometer (OLCR) with a high power tunable narrow-band light source which employs a fluoride-based erbium-doped fiber amplifier. The use of the amplifier simplifies the structure of the source and enables us to generate narrow-band light with a power of 18±0.2 dBm in the 1530-1560 nm wavelength range and with a reduced background level in each spectrum. The OLCR achieves a dynamic range of 47 dB and the signal fluctuations caused by residual speckle-like noise in the Rayleigh backscattering measurement are less than ±1 dB. This is the best data yet obtained with a diode-pumped fiber amplifier. The diagnosis of fiber-optic attenuators is successfully demonstrated using the OLCR     

Small intestinal metastasis from esophageal carcinoma associated with small intestinal obstruction: report of a case

The small intestine is rarely involved with metastatic tumors from outside the abdomen, and few case reports have been documented in the literature. We describe herein what to our knowledge is the third case of a solitary metastasis from squamous cell carcinoma (SCC) of the esophagus being found in the jejunum, causing small intestinal obstruction.     

Application of diamond films from CO-H2 plasma to tool blade coating

Diamond films were coated on WC-Co alloy tool blades using a microwave plasma of CO-H₂ mixed gas. Diamond film prepared at a CO concentration of 10% had good properties: Vickers hardness % 8500 kg mm^–2 and adhesion force 1.7 kg mm^–2. No peel-off of the diamond film was observed after a cutting test of an Al-Si alloy rod at a cutting speed of 450 m min^–1 for 0.5 h. It is thought that the high quality of the film originated from the selective etching of cobalt from the tool blade surface by CO-H₂ plasma.     

Diamond-like carbon films prepared from CH4-H2-H2O mixed gas using a microwave plasma

Diamond-like carbon films were synthesized on polished silicon substrates from CH₄-H₂-H₂O mixed gas using a microwave plasma technique. The film properties were studied. Their growth rate was several times as fast as that for CH₄-H₂ mixed gas under the same experimental conditions. The films have a large Vickers hardness (5000 to 6000 kg mm^–2), high electrical resistivity (10¹² to 10¹³ cm) and good optical transparency, especially in the infrared region. Low hydrogen and oxygen contents in the films were detected by secondary ion mass spectroscopy.     

Effect of Cold-Rolling on Precipitation Phenomena in Sensitized Type 316L and 304L Austenitic Stainless Steels

Precipitation phenomena in Type 316L and 304L stainless steels were studied mainly by transmission electron microscopic (TEM) observations after cold-rolling ranging from 0% (as solution annealed) to 80% reduction in thickness,and then by sensitization treatment. Precipitates were identified by electron diffraction analysis and EDS analysis.Precipitates observed in sensitized 316L stainless steel were sigma and chi phases, whereas carbide and sigma were observed in sensitized 304L stainless steel. Recrystallized grains were formed in 30% cold-rolled and sensitized 304L.However, the tendency toward recrystallization in sensitized 316L was much lower than in 304L. Precipitation of sigma and chi phases was accelerated by cold-rolling and they were observed at grain boundaries in lower cold-rolling; they were also seen, in grain interiors in higher cold-rolling. Higher deformation induced partially recrystallization combined with precipitation, resulting in the formation of heterogeneous microstructures.     

Structural ion selectivity of thia crown ether compounds with a bulky block subunit and their application as an ion-sensing component for an ion-selective electrode

Several 14-membered thia crown ether ionophores having a bulky block subunit were synthesized, and their chemical structures and ion selectivities were examined in detail when these compounds were used as an ion-sensing component of an ion-selective electrode. The ionophores of both cyclic and noncyclic thia ethers exhibited a high selectivity for silver ion (Ag(+)), in which the sulfur atom in the ionophore molecule plays a role as the effective coordination donor site for the silver ion. The best Ag(+)-selective electrode was prepared with the 14-membered thia crown ether having one sulfur atom, three oxygen atoms, and a bulky pinan subunit. The ion selectivity of this electrode for Ag(+) was over 10(4) times that for other metal cations. In the case where the sulfide in the thia ether ionophore was changed to sulfoxide by oxidation, ion selectivity for mercury ion became higher; therefore, the sulfoxide was found to be an effective coordination site for the mercury ion. The ion selectivity features of noncyclic sulfide, sulfoxide, and sulfone were also examined and compared with the results of the cyclic and noncyclic thia ethers.     

A new three-dimensional CT reconstruction method for cerebral arteriovenous malformation: development and clinical evaluation of see-through view method

The authors developed a new three-dimensional reconstruction method called "See-Through View (STV)" using a spiral CT in evaluating of cerebral arteriovenous malformation (AVM). Spiral CT was performed in eight patients with AVM. STV was obtained by reconstructing with a voxel transmission projection using a double threshold method. In all eight patients, STV images enable us to depict the nidus of AVM from all angles by see-throughing skull bone, evaluating the relationship of the vascular lesions adjacent to other cerebrovascular or skeletal structures. In conclusion, STV will provide us further spatial recognition, and will be greatly helpful for surgical planning.     

Evaluation of a mirror-polishing technique for fluorocarbon polymer surfaces for reduction of contamination from containers used in ultratrace analysis

A mirror-polishing technique for fluorocarbon polymer surfaces using high-precision diamond cutting tools was developed. The goal of this technique was the reduction of ultratrace elemental analysis contamination levels of containers fabricated from such mirror-polished materials. Remarkably smooth inner surfaces with degrees of flatness of 0.1 μm peak-to-valley (PTV) for containers fabricated from mirror-polished PTFE materials were obtained, in contrast to degrees of surface flatness of more than 30 μm PTV for commercially available PTFE containers. (Here, PTV denotes the difference between the highest peak and deepest valley in a scanned area of 10 × 10 μm.) Extractable impurity levels for mirror-polished PTFE container surfaces were reduced by more than 1 order of magnitude relative to those of unpolished PTFE containers. The surface conditions of the PTFE containers were observed by atomic force and scanning electron microscopy. The microphotographs so obtained suggest that the degree of surface smoothness of the containers is proportional to their ultratrace metallic contamination levels.     

Orthotropic material orientation optimization method in composite laminates

This paper proposes a optimization method that is capable of simultaneous design of multiple layers in a composite laminate with respect to multiple objective functions. The optimization process obtains a continuous orientation of an orthotropic material for each layer of the laminate. Each layer by itself is a single design domain, which allows multiple domains to be stacked in various orientations. Multiple optimization objectives are considered resulting in layers that perform different functions. The layers are modeled within a three-dimensional structure and by discretizing the structure using three-dimensional elements, the interaction between individual layers can be modeled. This also allows the optimization method to obtain a three-dimensional orientation vector. In this study, the individual layers are assumed to be thin, limiting the orientation vector to the mid-plane of the layer. The optimization model is tested on a two-layer laminate in which one layer is optimized for thermal control by directing heat toward specified sections while shielding other sections and the second layer is optimized to reduce the total deformation of the laminate structure that results from the thermal load. The results of simultaneous optimization for both layers are shown for several different configurations of boundary conditions.