Development and applications of an analytical electron microscope with a field emission electron gun

An analytical electron microscope with a field emission electron gun has been developed in order to improve the function of material identification, in order to obtain higher resolution of images, sharper electron diffraction patterns, and purer x-ray spectra with no effects of contamination from smaller areas than in the conventional instruments so far utilized. The performance capabilities of this newly developed analytical electron microscope, the Model H-600FE, have been examined and found to be very useful for the material characterization of nanometer-size areas. Various attributes of the microscope became apparent with reference to the results of different studies. These include better convergence of the electron beam (demonstrated by examination of an MoS₂ thin film), high-resolution transmission electron microscopy (using a gold film), high-resolution scanning electron microscopy (with a carbon film containing nanometer-size holes), high-angle resolution electron diffraction (of an iron carbide film), and precision x-ray analysis of nanometer-size areas (using a pyroxene crystal and a Cu---Zn---Al shape memory alloy).     

Repeated vergence adaptation causes the decline of visual functions in watching stereoscopic television

To evaluate visual fatigue when viewing stereoscopic TV, a technology expected to become the broadcasting display system of the future. Wide public acceptance of stereoscopic TV awaits resolution of many issues, including visual fatigue on viewing TV images. Visual fatigue was induced using a visual function simulator, consisting of prism and lens optical systems, while viewing stereoscopic TV. We assessed subject visual fatigue through subjective reports of symptoms and by the changes in visual functions. These functions included: viewer B [Js fusional break point, recovery point, accommodation step response, and visual evoked cortical potentials (VECP)]. Significant changes of some visual functions were found after watching simulated stereoscopic TV when the vergence load was heavy or when it changed over time; relative vergence limits decreased and the latency of VECP increased after watching, reflecting visual fatigue. After subjects rested, relative vergence limits recovered to pre-viewing levels. Our findings lead us to conclude that, aside from excessive horizontal binocular parallax, discontinuous changes in parallax is also a major factor that contributes to visual fatigue in the viewing of stereoscopic images. It also causes a decreased range of relative vergence, accommodation response, and a delay in the P100 latency of VECP.     

Microscopic implication of rapid shrinking of comb-type grafted poly(N-isopropylacrylamide) hydrogels

The shrinking mechanism of comb-type grafted poly(N-isopropylacrylamide) gel was investigated by small-angle X-ray scattering (SAXS). The SAXS reveals that the microdomain structure with characteristic spacing of 460 Å is developed in the comb-type grafted poly(N-isopropylacrylamide) gel during the shrinking process. These observations suggest that the freely mobile characteristics of the grafted chains are expected to show the rapid dehydration to make tightly packed globules with temperature, followed by the subsequent hydrophobic intermolecular aggregation of the dehydrated graft chains. The dehydrated grafted chains created the hydrophobic cores, which enhance the hydrophobic aggregation of the networks. These aggregations of the NIPA chains contribute to an increase in void volume, which allow the gel having a pathway of water molecules by the phase separation.     

Quantitative acoustic emission source characterization of microcrackings in steel

Acoustic emission (AE) source wave analysis is a new NDE technique for the investigation of dynamic fracture process. We applied this technique to the quantitative characterization of crack sources in ductile fracture. Using two samples of ASTM A533B steel with different sulfur content, acoustic emissions during fracture toughness tests were detected, located, and analyzed. The detected AE signals were classified into two types according to the analyzed source waveforms. One was a signal due to microcracking at the MnS inclusion, and the other was a signal due to coalescence of the voids. The results of the source wave analysis showed that microcracking at the inclusions was due to Mode I type tension crack with sizes of 10–30 µm, and the coalescence of the voids was due to tension shear mixed cracks with sizes of 60–100 µm. It was confirmed that this technique is very effective for the quantitative evaluation of microcrackings and for the detection of the nucleation and growth of cracks.     

Lasing band-edge identification for a surface-emitting photonic crystal laser

The possibility of single-mode oscillation over a large cavity area for photonic crystal lasers emitting at the photonic band edge has resulted in much interest in such materials for new forms of solid-state laser. In this paper, we measure the photonic bandstructure in our sample and identify the lasing band edge. By mapping out the bandstructure at the /spl Gamma/-point, we have observed fine structure at the band edge. The experimental results are in good agreement with the theoretically predicted bandstructure. Above threshold, we observe a lasing peak at 965 nm at one of the band edges. The far-field distribution of the laser is measured, showing an annular profile and azimuthal polarization. Calculations on the far-field distribution at the lasing band edge suggest the annular profile is due to an anti-symmetric resonant mode.     

Deriving protocol specifications from service specifications written in LOTOS

Summary.  A complete communication system is broken down into a number of protocol layers each of which provides services to the layer above it and uses services provided by its underlying layer. A service specification defines a particular ordering of the operations that a given layer provides to the layer above it. The active elements in each layer are called entities and they use a protocol in order to implement their service definition. On the basis of this relation between the service and protocol concepts we have developed algorithms for deriving protocol entity specifications from a formal service specification. The derived protocol entities ensure the correct ordering of the service primitives by exchanging synchronization messages through an underlying communication medium. This paper presents an extended version of our earlier derivation algorithms. This version of the algorithm can handle all operators and unrestricted process invocation and recursion as defined by basis LOTOS. The correctness of this derivation algorithm is formally proved. Received: January 1992 / Accepted: February 1996     

Efficacy of cefditoren pivoxil in the treatment of acute otitis media due to benzylpenicillin-insensitive Streptococcus pneumoniae

Clinical and bacteriological studies were carried out on cefditoren pivoxil (CDTR-PI) granule in infantile purulent acute otitis media treated at general practice settings and the following findings were obtained: 1. Two hundred forty eight strains were isolated from 210 patients, almost all of which (81.1%) harbored the following two strains: Streptococcus pneumoniae (42.3%) and Haemophilus influenzae (38.8%). Among S. pneumoniae, benzylpenicillin (PCG)-insensitive S. pneumoniae, (PISP) or PCG-resistant S. pneumoniae (PRSP) was 36.2%, corresponding to 15.3% of all the isolates and found in 18% of all patients. 2. The bacteria in the middle ear discharge and the nasopharyngeal swabs were correlated with conformity rate of more than 80% with regard to Streptococcus pyogenes, S. pneumoniae and H. influenzae but no Staphylococcus aureus was detected simultaneously from the two sources in any of the patients. S. aureus and coagulase-negative staphylococci (CNS) were considered to be contaminants that were originated from the external auditory meatus at the time of sampling. 3. Frequencies of isolation of S. pneumoniae from different age groups were higher in a lower age group between 0 and 4 years and those of PISP or PRSP had the similar tendency. 4. Antibacterial activities were determined for CDTR and related oral antibiotics against the strains of S. pneumoniae and H. influenzae as representative isolates. CDTR had stronger antibacterial activities against both bacteria than the reference antibiotics. CDTR was found to be transferred into the otorrhea at a mean concentration of 0.58 micrograms/ml after single administration of CDTR-PI granule formulation at 3 mg(potency)/kg. 5. As for bacterial eradication efficacies in the middle ear cavity and the nasopharynx, eradication rates were higher than 80% in the middle ear cavity in all cases without large differences among bacterial species but eradication rate of PISP was 30% in the nasopharynx, and it was significantly lower than those of PSSP and other bacteria. 6. In view of clinical effectiveness, the efficacy rate was 89.4% and bacteriological effects was 92.2%; in view of safety, adverse reactions were; observed in 9.5% and the rate of usefulness was 89.4%. 7. From above-stated results, CDTR-PI was considered as a useful oral antibiotic for infantile acute otitis media including PISP infections.     

Novel sensing system for glucose based on the complex formation between phenylborate and fluorescent diol compounds

From the standpoints of long-term stability and simple handling, a glucose sensor composed of totally synthetic sensing moieties should be of great advantage. This study was performed to demonstrate the feasibility of a novel glucose sensing system in an aqueous milieu based on a change in the fluorescence on competitive binding between a fluorescent diol compound and glucose toward a phenylborate compound. 6,7-Dihydroxy-4-methyl-coumarin (DHMC) was selected as a fluorophore, and 3-propionamidophenylboronic acid (PAPBA) as a phenylborate compound. The relationship between the glucose concentration and fluorescence intensity was linear in the range of 0 to 500 mg/dl of glucose. The availability of various derivatives of DHMC and phenylborate compounds allows the incorporation of these functionalities on the tip of an optical fiber to construct an opto-sensing system for glucose.