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131.
An improvement of Fourier synthesis optics for hard x-ray imaging is described, and the basic performance of the new optics is confirmed through numerical simulations. The original concept of the Fourier synthesis imager utilizes nonposition-sensitive hard x-ray detectors coupled to individual bigrid modulation collimators. The improved concept employs a one-dimensional position-sensitive detector (such as a CdTe strip detector) instead of the second grid layer of each bigrid modulation collimator. This improves the imaging performance in several respects over the original design. One performance improvement is a two-fold increase in the average transmission, from 1/4 to 1/2. The second merit is that both the sine and cosine components can be derived from a single grid-detector module, and hence the number of imaging modules can be halved. Furthermore, it provides information along the depth direction simultaneously. This in turn enables a three-dimensional imaging hard x-ray microscope for medical diagnostics, incorporating radioactive tracers. A conceptual design of such a microscope is presented, designed to provide a field of view of 4 mm and a spatial resolution of 400 microm. 相似文献
132.
Though molecular biology-based visualization techniques such as antibody staining, in situ hybridization, and induction of reporter gene expression have become routine procedures for analyzing the structures of the brain, precautions to prevent misinterpretation have not always been taken when preparing and interpreting images. For example, sigmoidal development of the chemical processes in staining might exaggerate the specificity of a label. Or, adjustment of exposure for bright fluorescent signals might result in overlooking weak signals. Furthermore, documentation of a staining pattern is affected easily by recognized organized features in the image while other parts interpreted as "disorganized" may be ignored or discounted. Also, a higher intensity of a label per cell can often be confused with a higher percentage of labeled cells among a population. The quality, and hence interpretability, of the three-dimensional reconstruction with confocal microscopy can be affected by the attenuation of fluorescence during the scan, the refraction between the immersion and mounting media, and the choice of the reconstruction algorithm. Additionally, visualization of neurons with the induced expression of reporter genes can suffer because of the low specificity and low ubiquity of the expression drivers. The morphology and even the number of labeled cells can differ considerably depending on the reporters and antibodies used for detection. These aspects might affect the reliability of the experiments that involves induced expression of effector genes to perturb cellular functions. Examples of these potential pitfalls are discussed here using staining of Drosophila brain. 相似文献
133.
This study focuses on the coagulation mechanism by the purified coagulant solution (MOC-SC-PC) with the coagulation active component extracted from M. oleifera seeds using salt solution. The addition of MOC-SC-PC tap water formed insoluble matters. This formation was responsible for kaolin coagulation. On the other hand, insoluble matters were not formed when the MOC-SC-PC was added into distilled water. The formation was affected by Ca2+ or other bivalent cations which may connect each molecule of the active coagulation component in MOC-SC-PC and form a net-like structure. The coagulation mechanism of MOC-SC-PC seemed to be an enmeshment of Kaolin by the insoluble matters with the net-like structure. In case of Ca2+ ion (bivalent cations), at least 0.2 mM was necessary for coagulation at 0.3 mgC l-1 dose of MOC-SC-PC. Other coagulation mechanisms like compression of double layer, interparticle bridging or charge neutralization were not responsible for the coagulation by MOC-SC-PC. 相似文献
134.
The respective influences of exposure and inborn neural networks on conspecific and nonconspecific face processing remain unclear. Although the importance of exposure in the development of object and face recognition in general is well documented, studies explicitly comparing face recognition across species showed a species-specific effect. For instance, laboratory monkeys exposed daily to human faces were better at discriminating monkeys than humans, suggesting that the role of exposure may not be the only factor affecting cross-species recognition. In the present study, the authors investigated conspecific and nonconspecific face recognition in chimpanzees (Pan troglodytes) from 2 primate centers that provided different exposure to chimpanzee and human faces. The authors showed that the chimpanzees from the center providing more exposure to human faces than to chimpanzee faces were better at discriminating human faces than they were at discriminating chimpanzee faces. The chimpanzees from the other center did not show the same effect. A computational simulation was developed to evaluate the average similarities among human pictures and among chimpanzee pictures. Both categories were comparable. Chimpanzees' scores were significantly correlated with the similarity coefficients. Overall, the results show that exposure is a critical determinant in conspecific and nonconspecific face recognition. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
135.
Sachio Okada Takeyuki Kikuchi Masafumi Kobune Tetsuo Yazawa 《Thin solid films》2007,515(18):7342-7346
A mixed ionic and electronic conducting hydrogen separation membrane, which consisted of proton-conductive oxide and metallic palladium, was fabricated. A porous alumina tube was employed as a support, and proton-conductive oxide particles were introduced into a microporous top layer of the support by an impregnation method. Palladium particles were deposited into the same porous layer by chemical vapor deposition. Hydrogen permeated preferentially via the membrane thus obtained with a hydrogen permeance (PH2) of 1.2 × 10− 9 mol·m− 2·s− 1·Pa− 1 at 873 K. Selectivity for hydrogen (PH2/PN2) increased with the operating temperature due to an increase in proton conductivity of the membrane, and PH2/PN2 = 5.7 was attained at 873 K. 相似文献
136.
An atmospheric-pressure glow-discharge micro plasma in contact with liquid paraffin is stably generated by using a capacitively coupled plasma method with a mesh electrode. When characteristics of the plasma are measured in the boundary between the micro plasma (gas-phase) and liquid paraffin (liquid-phase) using optical emission spectroscopy, spectrum peaks of the emission of CH and C2 which dissociate from paraffin are observed. The result indicates that solution can feed particles to the plasma at gas-liquid interface and this plasma is accordingly expected to promote an attractive plasma process for creating materials consisting of elements in various solutions. 相似文献
137.
In the densely-populated urban areas, pedestrian flows often cross each other and congestion is caused. The congestion makes us feel uncomfortable and sometimes leads to pedestrian accidents. To reduce the congestion or the risk of accidents, it is required to control the swarm behavior of pedestrian flows. This paper proposes modeling and controlling method of the crossing pedestrian flows. In the social/urban engineering, it is well known that the swarm behavior with a diagonal stripe pattern emerges in the crossing area of the flows. This is a self-organized phenomenon caused by the local collision avoidance effect of the pedestrians. To control the macroscopic behavior of the flows, we utilize this self-organized phenomenon. Firstly, we propose the continuum model of the crossing pedestrian flows. In the continuum model, the dynamic change of the congestion in the diagonal stripe pattern is simulated as the density. Secondly, the novel control method to improve average flow velocity is proposed based on the model. The proposed method utilizes the dynamic interaction between the diagonal stripe pattern and guides, who are moving in the flows. The authors derive the control algorithm through an analysis on the temporal and spatial frequencies of the crossing flows. The validity is verified with simulations using the continuum model. Moreover, we apply the proposed method to the particle model, assuming the actual pedestrians. 相似文献
138.
Catalin Popa Yuki Okayasu Ken-ichi Katsumata Toshihiro Isobe Nobuhiro Matsushita Akira Nakajima Taisuke Kurata Kiyoshi Okada 《Journal of Materials Science》2013,48(2):941-947
Porous mullite ceramics with unidirectionally oriented pores were prepared by an extrusion method using rayon fibers as the pore formers. Rayon fibers of 8.1, 9.6, 16.8, and 37.6 μm in diameter were used as the pore formers and were kneaded with alumina powder, kaolin clay, China earthen clay, and water to form pastes. These pastes were extruded into cylindrical tubes, dried, and fired at 1500 °C for 4 h. The apparent porosities ranged from 45.7 to 48.2 %. The pore size distributions showed a sharp peak at 9.4, 10.0, 15.6, and 30 μm with increasing fiber diameters. The height of the capillary rise was 1780, 1670, 1320, and 950 mm with increasing fiber diameter. The maximum capillary rise is much higher than previously reported. The contact angle and effective pore radius that determine the capillary rise ability were calculated by fitting the capillary rise curves using the Fries and Dreyer’s equation. 相似文献
139.
Yasuyoshi Fukui Hiroshi Okada Noriyoshi Kumazawa Yashimi Watanabe 《Metallurgical and Materials Transactions A》2000,31(10):2627-2636
A possibility to make near-net-shape functionally graded material (FGM) products has been examined. The FGM billets having
a graded volume fraction of Al3Ni in thickness direction were machined from an Al-Al3Ni FGM thick-walled tube manufactured by a vacuum centrifugal method. Billets, which were set in the container for the backward
extruding, were heated to 650 °C to 680 °C, at which temperature the FGM becomes a mixture of molten aluminum eutectic and
solid intermetallics. Then, billets were extruded successfully to FGM cups by a semisolid forming, except at 650 °C. Residual
bulky Al3Ni particles are found at higher temperature. Thus, an optimum operation temperature is found to be around 660 °C, because
bulky Al3Ni particles transform to fine spheroidal or fibrous shape after the forming. The volume fraction of intermetallics at the
bottom region of the cup was condensed more than 60 vol pct in a proper billet setting. 相似文献
140.
Mitsutoshi Okada Tohru Hisamatsu Takayuki Kitamura 《Journal of Thermal Spray Technology》2009,18(1):90-95
A superalloy with a thermal barrier coating (TBC) simulating a gas turbine blade is exposed to a high-temperature environment
to develop a method for predicting the local temperature and Al content in a bond coat (BC). The Al content decreases with
an increase in the test time due to the Al transport induced by the oxidation of the BC and the interdiffusion between the
BC and the substrate. This brings about Al-decreased layer (ADL) at the boundary between the BC and the top coat. The thickness
of the ADL increases in proportion to the square root of the test time, and the temperature dependence of the growth rate
shows an Arrhenius-type behavior. Based on this relation, the local temperature of an in-service blade can be estimated by
measuring the ADL thickness when the operation time is known. The Al content decreases in proportion to the ADL thickness.
The prediction method of the Al content based on the relation is also presented. 相似文献