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71.
New efficient intermetallide catalysts for hydrogen storage in reversible processes of aromatics hydrogenation and naphthene dehydrogenation were studied. These catalysts provide an enhanced activity in the dehydrogenation of saturated organic molecules, with no side reactions like cracking, hydrogenolysis, ring opening, or coke formation occurring on these catalysts. The use of intermetallides provides some hydrogen storage capacity in the low-temperature region, while their catalytic activity in the dehydrogenation affords the hydrogen supply in the high-temperature range. 相似文献
72.
The paper presents a simple but efficient new numerical scheme for the integration of nonlinear constitutive equations. Although it can be used for the integration of a system of algebraic and differential equations in general, the scheme is primarily developed for use with the direct solution methods for solving boundary value problems, e.g. explicit dynamic analysis in ABAQUS/Explicit. In the developed explicit scheme, where no iteration is required, the implementation simplicity of the forward-Euler scheme and the accuracy of the backward-Euler scheme are successfully combined. The properties of the proposed NICE scheme, which was also implemented into ABAQUS/Explicit via User Material Subroutine (VUMAT) interface platform, are compared with the properties of the classical forward-Euler scheme and backward-Euler scheme. For this purpose two highly nonlinear examples, with the von Mises and GTN material model considered, have been studied. The accuracy of the new scheme is demonstrated to be at least of the same level as experienced by the backward-Euler scheme, if we compare them on the condition of the same CPU time consumption. Besides, the simplicity of the NICE scheme, which is due to implementation similarity with the classical forward-Euler scheme, is its great Advantage. 相似文献
73.
Yoav Linzon Boris A. Malomed Michael Zaezjev R. Morandotti Maite Volatier-Ravat Vincent Aimez Richard Ares Shimshon Bar-Ad 《Mathematics and computers in simulation》2009
The nonlinear interactions between discrete optical solitons that propagate in different regimes of diffraction, and the nonlinear scattering of dispersive waves by local optical potentials, were studied experimentally. It is well known in electromagnetism that when linear coherent waves meet they interfere without interactions. Linear waves also scatter through local optical structures without exchanging any power with guided and anti-guided modes of these structures. When a focusing Kerr nonlinearity is present, linearly inhibited phenomena, which break these rules, are shown to exist. Our studies were performed with Silica glass and semiconductor AlGaAs nonlinear planar modulated waveguides, excited by ultra-short pulses in the near infrared spectral regime. 相似文献
74.
Changes in urokinase-plasminogen activator (u-PA) and u-PA receptor (u-PAR) expression at the protein and mRNA level in resting neutrophils and in neutrophils activated by phorbol myristate acetate (PMA) were examined. Low amounts of u-PA were found intracellularly or membrane-bound in resting neutrophils. However, incubation of resting neutrophils with purified exogenous u-PA (10 IU/ml) revealed extensive binding of u-PA to cell membranes. Excess amino-terminal fragment of the u-PA molecule, a proteolytically inactive fragment of u-PA (amino acids 1-135) blocked binding of exogenous u-PA to the cell membrane. These results, collectively, indicate that the binding of u-PA is specific and that resting neutrophils have unoccupied u-PA receptors on their cell membrane. Addition of PMA led to an increase (P < 0.01) in total cell-associated, membrane-bound u-PA activity and u-PA mRNA expression by bovine neutrophils. In contrast. PMA increased u-PAR mRNA levels but this was accompanied by a decrease (2.5-fold; P < 0.01) in free, unoccupied u-PA binding sites. No significant effects on total cell-associated or membrane-bound u-PA were found when neutrophils were treated with 4-phorbol 12,13 didecanoate, a phorbol ester that does not activate protein kinase C (PKC). Furthermore, addition of 1-(5-isoquinolinesylphonyl)-2-methlylpiperazine dihydrochloride (H-7), a potent PKC inhibitor, blocked the effect of PMA on total cell-associated u-PA activity. Thus, PKC plays a role in the modulation of u-PA and u-PAR by PMA in bovine neutrophils. 相似文献
75.
A feasibility study for electrical impedance tomography as a means to monitor tissue electroporation for molecular medicine 总被引:3,自引:0,他引:3
Molecular medicine involves the introduction of macromolecules, such as drugs or gene constructs, into specific cells of the body. Electroporation, which uses electric pulses to permeate cell membranes, is a method for achieving this. However, as with other molecular medicine procedures, it lacks a real-time mechanism to detect and control which cells have been affected. We propose and demonstrate, via computer simulation, that electrical impedance tomography has the potential for detecting and imaging electroporation of cells in tissue in real-time, thereby providing feedback for controlling electroporation. 相似文献
76.
Zoran Hadzi-Velkov Boris Spasenovski 《International Journal of Wireless Information Networks》2002,9(3):191-199
In this paper, we estimated the influence of capture effect over the capacity of IEEE 802.11b DCF within a single picocell. The channel utilization is examined analytically by introducing two capture models based on Rayleigh-distributed envelopes of the captured and the interfering frames divided into two local-mean power classes. Simulations in a pure Rician-faded channel depict the conditions under which both Rayleigh-faded capture models can be used to accurately predict the peak network capacity. Unlike the RTS/CTS handshake access mode, Basic access mode is significantly sensitive to the capture ratio, i.e., the receiver design. The packet size threshold over which it is convenient to switch from Basic to RTS/CTS handshake access scheme is also sensitive to the capture effect. 相似文献
77.
A suffix tree approach to anti-spam email filtering 总被引:1,自引:0,他引:1
We present an approach to email filtering based on the suffix tree data structure. A method for the scoring of emails using
the suffix tree is developed and a number of scoring and score normalisation functions are tested. Our results show that the
character level representation of emails and classes facilitated by the suffix tree can significantly improve classification
accuracy when compared with the currently popular methods, such as naive Bayes. We believe the method can be extended to the
classification of documents in other domains.
Editor: Tom Fawcett 相似文献
78.
We describe a patient with pauciarticular juvenile rheumatoid arthritis with aortic insufficiency who underwent successful aortic valve replacement with a mechanical prosthetic valve. 相似文献
79.
36 3-mo-old infants interacted with their mothers under conditions in which they could see and hear their mothers (correlated auditory plus visual information: A?+?V), see but not hear their mothers (V), and hear but not see their mothers (A); the latter 2 conditions are termed perceptual paradox. The interactions were videotaped, and the Ss' behavior was judged by naive observers who used a subjective 7-point rating scale of infant affect. For 2 groups of Ss, 3 1-min presentations of the A?+?V condition were alternated with 3 1-min presentations of either A (Group 1) or V (Group 2) conditions. In both groups, Ss were judged as being more distressed during unimodal presentations than during bimodal presentations. In a 3rd group, unimodal (A) presentations were alternated with unimodal (V) presentations. Ss in this group were significantly more distressed when they could hear but not see their mothers than when they could see but not hear their mothers. Results demonstrate the suitability of global subjective ratings of affective state in studies of infant perception. (17 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
80.
Ruder Boskovi? Institute (RBI) criticality dosimetry system consists of a chemical dosimetry system for measuring the total (neutron + gamma) dose, and a thermoluminescent (TL) dosimetry system for a separate determination of the gamma ray component. The use of the chemical dosemeter solution chlorobenzene-ethanol-trimethylpentane (CET) is based on the radiolytic formation of hydrochloric acid, which protonates a pH indicator, thymolsulphonphthalein. The high molar absorptivity of its red form at 552 nm is responsible for a high sensitivity of the system: doses in the range 0.2-15 Gy can be measured. The dosemeter has been designed as a glass ampoule filled with the CET solution and inserted into a pen-shaped plastic holder. For dose determinations, a newly constructed optoelectronic reader has been used. The RBI team took part in the International Intercomparison of Criticality Accident Dosimetry Systems at the SILENE Reactor, Valduc, June 2002, with the CET dosimetry system. For gamma ray dose determination TLD-700 TL detectors were used. The results obtained with CET dosemeter show very good agreement with the reference values. 相似文献