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11.
The electrochemistry of VS2 in molten NaAlCl4 has been investigated in relation to its usefulness as a reversible positive electrode for sodium batteries operating in the moderate temperature range of 160–200°C. VS2 reacted with NaAlCl4 during early stages of cell cycling, and became VS2Cl showing a reversible capacity of 2.8 electrons/vanadium. The electrochemistry of mixtures of VCl3 and S in molten NaAlCl4 showed similarities to that of VS2Cl. The VSxCly cathodes obtained via the two different routes exhibited excellent rechargeability as evidenced by the long-term cycling behavior of cells of the configuration, Na(l)/β″-Al2O3/NaAlCl4(l), cathode material. When NbS2Cl2 was used as the cathode material it underwent a structural change in the first cycle to form what appeared to be NbS2Cl2, the Nb analog of VSxCly. The structurally modified niobium sulfur chloride cathode exhibited excellent rechargeability. 相似文献
12.
Aronson Carl Lawrence Beloskur Douglas Frampton Isaac S. McKie Justin Montbriand Paul 《Polymer Bulletin》2004,52(6):409-419
Summary Functionalization of both linear poly(4-hydroxystyrene) (PHS) and branched poly(4-hydroxystyrene) (PHS-B) was accomplished via a Reimer-Tiemann electrophilic aromatic substitution reaction. Linear and branched poly(4-hydroxystyrene-co-5-vinylsalicylaldehyde) (pHS/5VSA and pHS-B/5VSA) copolymers were observed to undergo acid-catalyzed, novolac type self-crosslinking. Both the pHS/5VSA and pHS-B/5VSA copolymer systems possessed a lower deep ultra violet microlithographic sensitivity compared to linear PHS when formulated in negative photoresists. The sluggishness of the negative photoresists containing 5-vinylsalicylaldehyde functionalized copolymers was attributed to a combination of resonance stabilization and steric hindrance effects. 相似文献
13.
Assignment Games with Conflicts: Robust Price of Anarchy and Convergence Results via Semi-Smoothness
We study assignment games in which jobs select machines, and in which certain pairs of jobs may conflict, which is to say they may incur an additional cost when they are both assigned to the same machine, beyond that associated with the increase in load. Questions regarding such interactions apply beyond allocating jobs to machines: when people in a social network choose to align themselves with a group or party, they typically do so based upon not only the inherent quality of that group, but also who amongst their friends (or enemies) chooses that group as well. We show how semi-smoothness, a recently introduced generalization of smoothness, is necessary to find tight bounds on the robust price of anarchy, and thus on the quality of correlated and Nash equilibria, for several natural job-assignment games with interacting jobs. For most cases, our bounds on the robust price of anarchy are either exactly 2 or approach 2. We also prove new convergence results implied by semi-smoothness for our games. Finally we consider coalitional deviations, and prove results about the existence and quality of strong equilibrium. 相似文献
14.
M. B. Maple M. C. de Andrade J. Herrmann Y. Dalichaouch D. A. Gajewski C. L. Seaman R. Chau R. Movshovich M. C. Aronson R. Osborn 《Journal of Low Temperature Physics》1995,99(3-4):223-249
Experimental efforts to characterize and develop an understanding of non Fermi liquid (NFL) behavior at low temperature in f-electron materials are reviewed for three f-electron systems: M1–xUxPd3 (M = Sc, Y), U1–xThxPd2Al3, and UCu5–xPdx. The emerging systematics of NFL behavior in f-electron systems, based on the present sample of nearly ten f-electron systems, is updated. Many of the f-electron systems exhibit the following temperature dependences of the electrical resistivity p, specific heat C, and magnetic susceptibility for T T0, where To is a characteristic temperature: P(T) 1 –aT/T
0, where a < 0 or > 0, C(T)/T (-1/T
o) In (T/bT
0), and (T) 1 –c(T/To)1/2. In several of the f-electron systems, the characteristic temperature To can be identified with the Kondo temperature Tk. 相似文献
15.
'Grid cells' in the dorsocaudal medial entorhinal cortex (dMEC) are activated when a rat is located at any of the vertices of a grid of equilateral triangles covering the environment. dMEC grid cells have different frequencies and phase offsets. However, cells in the dentate gyrus (DG) and hippocampal area CA3 of the rodent typically display place fields, where individual cells are active over only a single portion of the space. In a model of the hippocampus, we have shown that the connectivity from the entorhinal cortex to the dentate granule cells could allow the dentate granule cells to operate as a competitive network to recode their inputs to produce sparse orthogonal representations, and this includes spatial pattern separation. In this paper we show that the same computational hypothesis can account for the mapping of EC grid cells to dentate place cells. We show that the learning in the competitive network is an important part of the way in which the mapping can be achieved. We further show that incorporation of a short term memory trace into the associative learning can help to produce the relatively broad place fields found in the hippocampus. 相似文献
16.
Current methods used clinically to assess myocardial perfusion are invasive and expensive. As the technology of ultrasound imaging improves, CE may provide a relatively inexpensive, noninvasive means of quantitating myocardial perfusion. Issues regarding stability of microbubble contrast agents must be studied more closely under physiologic conditions. As such, encapsulated microbubbles may provide more stability under physiologic pressures than free gas microbubbles. Introducing high concentrations of contrast, either by hyperconcentrating the contrast agent or by increasing the injection rate, may provide greater stability under physiologic conditions. Further, before quantitative statement of tissue perfusion can be made, the relationship between tracer concentration and system response must be established. Further, a "linear" postprocessing ultrasound setting does not eliminate this requirement as data must still undergo nonlinear transformation during log compression and time-gain compensation. Additionally, issues regarding "electronic thresholding" must be explored more extensively in vivo. Commercial ultrasound scanners, in their present form, may not offer adequate sensitivity for absolute quantitative studies. Further development of modified ultrasound systems may provide sufficient sensitivity for quantitative perfusion imaging. CE offers a potentially powerful tool in the clinical management of patients with ischemic heart disease. Conventional coronary angiography provides information on the size of a lesion, but accompanying tissue perfusion distal to the lesion cannot be determined. Doppler ultrasonography determines velocity of blood flow in large vessels but does not offer the potential to quantitate tissue perfusion. Clearly, CE has a place in the future of diagnostic imaging. The recent work of Ito et al. demonstrated the qualitative potential of CE in the identification of "areas at risk" in patients who had undergone thrombolysis or percutaneous transluminal coronary angioplasty after an acute myocardial infarction. With further improvement in the ultrasound imaging techniques and microbubble stability, CE may offer an inexpensive, noninvasive means of assessing myocardial perfusion. 相似文献
17.
18.
Single-mother, cohabiting 2-parent, and married 2-parent families with infants were compared on maternal and infant behavior, Home Observation for Measurement of the Environment (HOME) scores, and infant's security of attachment. Married mothers and their infants demonstrated more positive behavior and received higher HOME scores when the infant was 6 and 15 months old than did their cohabiting and single counterparts. Married families were also better off than single and cohabiting families on several demographic, parent personality, financial, and social context measures. Single and cohabiting families were similar across most measures. Selection variables (maternal age, ethnic group, and education) explained much, but not all, of the family structure differences in the mother-infant relationship and the HOME. Maternal psychological adjustment, attitudes about child rearing, income, and social support explained little of the family structure variation, suggesting that characteristics that preceded marriage and conception were important determinants of family structure differences. (PsycINFO Database Record (c) 2010 APA, all rights reserved) 相似文献
19.
We present the results of analytical and numerical calculations of the free-surface shape and temperature distribution produced
in liquid metal droplets processed in the TEMPUS electromagnetic levitation facility. The mathematical models were developed
to predict the behavior of liquid metal droplets in containerless experiments used to measure thermophysical properties aboard
the Space Shuttle Columbia during the IML-2 mission in July 1994. A normal stress balance model was used to numerically calculate
the equilibrium free-surface shapes for various samples produced by a number of induction coil voltages. Analytical and numerical
calculations were performed to model the heat transfer in the liquid metal droplets during and following the heating coil
pulses. The work illustrates the use of mathematical modeling in the design of microgravity experiments and is applicable
to industrial processes such as casting and skull melting. 相似文献
20.
The performance of InGaP-based pHEMTs as a function of gate metallization is examined for Mo/Au, Ti/Au, and Pt/Au gates. DC and microwave performance of pHEMT's with 0.7-μm gate lengths is evaluated. Transconductance, threshold voltage, ft, and fmax are found to depend strongly on gate metallization. High-speed performance is achieved, with ft of 41.3 GHz and f max of 101 GHz using Mo/Au gates. The difference in performance between devices with different gate metallizations is postulated to be due to a combination of the difference in Schottky barrier heights and different gate-to-channel spacings due to penetration of the gate metal into the InGaP barrier layer 相似文献