Growth of LiF/LiBaF<Subscript>3</Subscript> eutectic scintillator crystals and their optical properties

Li-containing materials can be applied as neutron scintillators, and LiBaF₃ can discriminate neutron and gamma rays. Moreover, LIF/LiBaF₃ can have higher cross section of thermal-neutron capture compared with LiBaF₃. In this study, LiF (82.5 mol%) and (Ba_1?x RE _x )F₂ (17.5 mol%, RE = Ce and Eu, x = 0.002) eutectic crystals, LiF/RE:LiBaF₃, were grown by the micropulling down method with different pulling rates (growth rate) in order to observe the eutectic structure. Lamellar microstructure was formed for each pulling rate. LiF/Ce:LiBaF₃ excited by 5.5-MeV alpha rays had a broad peak at ~350 nm corresponding to 5d–4f transition of Ce³⁺. On the other hand, LiF/Eu:LiBaF₃ had two scintillation processes; a sharp emission was originated from ⁶P_7/2 → ⁸S_7/2 transitions in the 4f electronic configuration of Eu²⁺ at 360 nm, and a broad one was attributed to Eu²⁺ trapped exciton recombination at 400–450 nm. Since scintillation light was observed for these materials, these scintillators are sensitive to neutrons.     

Influence of pH on performance of sodium phosphinate for decreasing the particle size

To clarify the influence of pH on performance of sodium phosphinate (NaPH₂O₂) for decreasing particle size of Pt nanoparticles, carbon-supported Pt nanoparticles that contained phosphorus (P–Pt/C) were synthesised by an electron-beam irradiation reduction method (EBIRM) under four different pH conditions (pH = 3, 6, 9, and 12) and under five different NaPH₂O₂ concentrations (0.0, 0.5, 1.0, 3.0, and 5.0 mM). The relationship among pH, NaPH₂O₂ concentration, average particle size of Pt nanoparticle, and Pt loading weight was investigated in this study. The average particle size of Pt nanoparticles was in the range of 0.8–3.4 nm and lower in the order; pH12 > pH3 > pH6 > pH9; for example, under the same NaPH₂O₂ concentrations of 3.0 mM, the particle size of P–Pt/C prepared at pH = 12 and pH = 9 was 1.5 and 0.8 nm, respectively. In addition, Pt loading weight was also lower in the order; pH12 > pH3 > pH6 > pH9. In summary, these results indicated that the pH in the precursor solution affected the performance of NaPH₂O₂. These findings would be useful for controlling the particle size of monometallic Pt and Pt-based bimetallic nanoparticles supported on carbon particles for fuel cell applications.     

Learning word meanings and grammar for verbalization of daily life activities using multilayered multimodal latent Dirichlet allocation and Bayesian hidden Markov models

Intelligent systems need to understand and respond to human words to enable them to interact with humans in a natural way. Several studies attempted to realize these abilities by investigating the symbol grounding problem. For example, we proposed multilayered multimodal latent Dirichlet allocation (mMLDA) to enable the formation of various concepts and inference using grounded concepts. We previously reported on the issue of connecting words to various hierarchical concepts and also proposed a simple preliminary algorithm for generating sentences. This paper proposes a novel method that enables a sensing system to verbalize an everyday scene it observes. The method uses mMLDA and Bayesian hidden Markov models (BHMM) and the proposed algorithm improves the word inference of our previous work. The advantage of our approach is that grammar learning based on BHMM not only boosts concept selection results but enables our method to process functional words. The proposed verbalization algorithm produces results that are far superior to those of previous methods. Finally, we developed a system to obtain multimodal data from human everyday activities. We evaluate language learning and sentence generation as a complete process under this realistic setting. The results demonstrate the effectiveness of our method.     

Locating congested segments over the Internet by clustering the delay performance of multiple paths

Delay variation-based detection and location of congestion in a large network is considered. Since the Internet is still highly prone to performance deterioration due to transient large delays, locating a part of the network (segments) responsible is vital to ensure that Internet Service Providers can mitigate or prevent such performance deterioration. In the proposed method, the end-to-end packet delays from multiple origins to multiple destinations are actively and continuously measured. By analyzing those data on delay variation along each monitored path, congestion is detected by finding a delay performance deterioration worse than a predefined criteria and a congested segment responsible could be inferred by finding a set of paths among which delay variations are strongly correlated. This is a network tomographic approach based on a clustering technique that effectively tackles the correlation among packet delay variation along individual paths. The proposed method was evaluated through a real-world long-term experiment on the Japan’s commercial Internet, and was shown to have considerable potential to promptly locate congested segments through various analyses on the experimental results.     

Computer-aided diagnosis: the emerging of three CAD systems induced by Japanese health care needs

The aim of this paper is to describe three emerging computer-aided diagnosis (CAD) systems induced by Japanese health care needs. CAD has been developing fast in the last two decades. The idea of using a computer to help in medical image diagnosis is not new. Some pioneer studies are dated back to the 1960s. In 1998, the first U.S. FDA (Food and Drug Administration) approved commercial CAD system, a film-digitized mammography system, was launched by R2 Technologies, Inc. The success was quickly repeated by a number of companies. The approval of Medicare CAD reimbursement in the U.S. in 2001 further boosted the industry. Today, CAD has its significance in the economy of the medical industry. FDA approved CAD products in the field of breast imaging (mammography, ultrasonography and breast MRI) and chest imaging (radiography and CT) can be seen. In Japan, as part of the "Knowledge Cluster Initiative" of the government, three computer-aided diagnosis (CAD) projects are hosted at the Gifu University since 2004. These projects are regarding the development of CAD systems for the early detection of (1) cerebrovascular diseases using brain MRI and MRA images by detecting lacunar infarcts, unruptured aneurysms, and arterial occlusions; (2) ocular diseases such as glaucoma, diabetic retinopathy, and hypertensive retinopathy using retinal fundus images; and (3) breast cancers using ultrasound 3-D volumetric whole breast data by detecting the breast masses. The projects are entering their final development stage. Preliminary results are presented in this paper. Clinical examinations will be started soon, and commercialized CAD systems for the above subjects will appear by the completion of this project.     

Anisotropy in ac losses near the irreversibility field of Bi2Sr2CaCu2O8

The ac susceptibility under a biased dc field near the irreversibility field (H _irr) of a Bi₂Sr₂CaCu₂O₈ single crystal has been measured. The frequency dependence, the ac-power dependence, and the nearly lossless character of the vs.H _dc curve forHa-axis have been roughly explained from a reversible (elastic) fluxoid motion, while those forH c-axis have been explained from a thermally assisted flux-flow (TAFF) model. The obtained parameters are discussed in relation to anisotropic flux-pinning mechanisms in the layered structure of this compound.     

Monitoring x-ray beam damage on lipid films by an integrated Brewster angle microscope/x-ray diffractometer

We describe an integrated Brewster angle microscope (BAM), Langmuir trough, and grazing incidence x-ray diffraction assembly. The integration of these three techniques allows for the direct observation of radiative beam damage to a lipid monolayer at the air-water interface. Although beam damage has been seen in x-ray measurements, it has not been directly observed in situ at the micron scale. Using this integrated assembly, we examined the effects of radiative beam damage on Langmuir monolayers of 1,2-dimyristoyl-sn-glycero-3-[phospho-L-serine] (DMPS), 1:1 DMPS:1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine, and 1:1 DMPS:1,2-dioleoyl-sn-glycero-3-phosphocholine held at a constant surface pressure. For constant surface pressure experiments, we observed a marked decrease in the surface area of the film upon exposure to the beam due to photodissociation. For a condensed lipid film, a change in refractive index of the film was observed post-beam-exposure, indicating areas of damage. For DMPS in an oxygenated environment, the Bragg peak intensity decreased with beam exposure. In mixed monolayer systems, with saturated and unsaturated lipids, an increase in the number of small saturated lipid domains was seen as the unsaturated lipid was preferentially damaged and lost from the monolayer. We show that BAM is a highly effective technique for in situ observation of the effects of radiative damage at the air/water interface during a synchrotron experiment.     

Motion analysis of grip and release with fingers using simple magnetic detection system

We have developed a magnetic grip-and-release motion detection system to measure time differences among fingers during motion. We designed a magnetic sensing system consisting of a magnetic oscillation coil, sensing coil, and circuit unit. We measured wave forms of grip-and-release motion (15 s) of seven healthy volunteers using the system. To provide the grip-and-release timing of each finger, we used the reference voltage of each subject in the state of grasping a rod with a 30 mm diameter. Using the reference voltage, the time differences in the finger movements of all volunteers were detected. The detected grip-and-release time difference of both dominant and nondominant hands had a main tendency in which the closing movement of the little finger is fast, within 10 ms, and the opening movement is slow, within 13 ms. Our data suggest that the new magnetic sensing system has the potential to detect the quantitative value of the time difference in grip-and-release motion among fingers.     

Environmental stress cracking of poly(butylene succinate)/cellulose triacetate blend films

Blend films of poly(butylene succinate) (PBS) with cellulose triacetate (CTA) were prepared using a solvent‐cast technique. The environmental stress cracking (ESC) behavior of commercial PBS films and that of as‐prepared PBS/CTA blend films were investigated in an aqueous NaOH solution. It was found that the fracture behavior of PBS films can be analyzed by linear fracture mechanics, that is, the stress‐intensity factor, K, is found to control the crack‐growth rate, da/dt, in PBS films. The enhancement of da/dt induced by increasing the normality of NaOH(aq) is more marked at a high value of K rather than at a low value of K. Furthermore, the ESC behavior of the PBS/CTA blends was studied in NaOH(aq). It was found that the behavior cannot be analyzed by linear fracture mechanics and that the addition of CTA into PBS increases the ESC resistance of the blends. Large‐scale yielding of the material around the crack tip seems to be responsible for the high ESC resistance of the blends. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 87: 510–515, 2003     

Cold-active enzymes from cold-adapted bacteria

The properties of amylase, lipase and protease, excreted by newly isolated bacteria from snow-covered soil, salmon intestine and crab intestine, have been investigated. One amylase, one lipase, and three proteases have been characterized by shifts in their apparent optimal activities toward low temperatures and by reductions in their activation energy values. The discovered enzymes were rapidly inactivated at temperatures above the optimum (30 to 40°C). These results suggest that the enzymes are cold-active. The best cold-active protease producer, isolated from salmon intestine, has been identified as Flavobacterium balustinum by the analysis of 16S rRNA. The optimal growth temperature of this bacterium was 20°C, but a higher amount of protease activity was present at 10°C.