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91.
Redjala Sonya Ferhoum Rabah Aït Hocine Nourredine Azem Said 《Journal of Failure Analysis and Prevention》2019,19(2):536-542
Journal of Failure Analysis and Prevention - The aim of this paper is to characterize the thermal aging effect near the glass transition temperature of polycarbonate (PC) at different hold time.... 相似文献
92.
Paul B. Slater 《Quantum Information Processing》2018,17(4):83
We begin by investigating relationships between two forms of Hilbert–Schmidt two-rebit and two-qubit “separability functions”—those recently advanced by Lovas and Andai (J Phys A Math Theor 50(29):295303, 2017), and those earlier presented by Slater (J Phys A 40(47):14279, 2007). In the Lovas–Andai framework, the independent variable \(\varepsilon \in [0,1]\) is the ratio \(\sigma (V)\) of the singular values of the \(2 \times 2\) matrix \(V=D_2^{1/2} D_1^{-1/2}\) formed from the two \(2 \times 2\) diagonal blocks (\(D_1, D_2\)) of a \(4 \times 4\) density matrix \(D= \left||\rho _{ij}\right||\). In the Slater setting, the independent variable \(\mu \) is the diagonal-entry ratio \(\sqrt{\frac{\rho _{11} \rho _ {44}}{\rho _ {22} \rho _ {33}}}\)—with, of central importance, \(\mu =\varepsilon \) or \(\mu =\frac{1}{\varepsilon }\) when both \(D_1\) and \(D_2\) are themselves diagonal. Lovas and Andai established that their two-rebit “separability function” \(\tilde{\chi }_1 (\varepsilon )\) (\(\approx \varepsilon \)) yields the previously conjectured Hilbert–Schmidt separability probability of \(\frac{29}{64}\). We are able, in the Slater framework (using cylindrical algebraic decompositions [CAD] to enforce positivity constraints), to reproduce this result. Further, we newly find its two-qubit, two-quater[nionic]-bit and “two-octo[nionic]-bit” counterparts, \(\tilde{\chi _2}(\varepsilon ) =\frac{1}{3} \varepsilon ^2 \left( 4-\varepsilon ^2\right) \), \(\tilde{\chi _4}(\varepsilon ) =\frac{1}{35} \varepsilon ^4 \left( 15 \varepsilon ^4-64 \varepsilon ^2+84\right) \) and \(\tilde{\chi _8} (\varepsilon )= \frac{1}{1287}\varepsilon ^8 \left( 1155 \varepsilon ^8-7680 \varepsilon ^6+20160 \varepsilon ^4-25088 \varepsilon ^2+12740\right) \). These immediately lead to predictions of Hilbert–Schmidt separability/PPT-probabilities of \(\frac{8}{33}\), \(\frac{26}{323}\) and \(\frac{44482}{4091349}\), in full agreement with those of the “concise formula” (Slater in J Phys A 46:445302, 2013), and, additionally, of a “specialized induced measure” formula. Then, we find a Lovas–Andai “master formula,” \(\tilde{\chi _d}(\varepsilon )= \frac{\varepsilon ^d \Gamma (d+1)^3 \, _3\tilde{F}_2\left( -\frac{d}{2},\frac{d}{2},d;\frac{d}{2}+1,\frac{3 d}{2}+1;\varepsilon ^2\right) }{\Gamma \left( \frac{d}{2}+1\right) ^2}\), encompassing both even and odd values of d. Remarkably, we are able to obtain the \(\tilde{\chi _d}(\varepsilon )\) formulas, \(d=1,2,4\), applicable to full (9-, 15-, 27-) dimensional sets of density matrices, by analyzing (6-, 9, 15-) dimensional sets, with not only diagonal \(D_1\) and \(D_2\), but also an additional pair of nullified entries. Nullification of a further pair still leads to X-matrices, for which a distinctly different, simple Dyson-index phenomenon is noted. C. Koutschan, then, using his HolonomicFunctions program, develops an order-4 recurrence satisfied by the predictions of the several formulas, establishing their equivalence. A two-qubit separability probability of \(1-\frac{256}{27 \pi ^2}\) is obtained based on the operator monotone function \(\sqrt{x}\), with the use of \(\tilde{\chi _2}(\varepsilon )\). 相似文献
93.
Darton NJ Sederman AJ Ionescu A Ducati C Darton RC Gladden LF Slater NK 《Nanotechnology》2008,19(39):395102
The use of magnetic fields in magnetic resonance imaging (MRI) for the tracking and delivery of chemotherapeutics bound to superparamagnetic nanoparticles offers a promising method for the non-invasive treatment of inoperable tumours. Here we demonstrate that superparamagnetic magnetite nanoparticles fabricated by an easily scalable method can be driven and tracked in real time at high velocities in vitro using MRI hardware. Force balance calculations are consistent with the magnetic properties of individual 10 nm diameter particles that move collectively as micron sized agglomerates with hydrodynamic diameter similar to that inferred from zero-magnetic-field dynamic light scattering measurements. 相似文献
94.
Berchane NS Andrews MJ Kerr S Slater NK Jebrail FF 《Journal of materials science. Materials in medicine》2008,19(4):1831-1838
Biological adhesives, natural and synthetic, are of current active interest. These adhesives offer significant advantages
over traditional sealant techniques, in particular, they are easier to use, and can play an integral part in the healing mechanism
of tissue. Thus, biological adhesives can play a major role in medical applications if they possess adequate mechanical behavior
and stability over time. In this work, we report on the method of preparation of bovine serum albumin (BSA) into a biological
adhesive. We present quantitative measurements that show the effect of BSA concentration and cross-linker content on the bonding
strength of BSA adhesive to wood. A comparison is then made with synthetic poly(glycidyl methacrylate) (PGMA) adhesive, and
a commercial cyanoacrylate glue, which was used as a control adhesive. In addition, BSA samples were prepared and characterized
for their water content, tensile strength, and elasticity. We show that on dry surface, BSA adhesive exhibits a high bonding
strength that is comparable with non-biological commercial cyanoacrylate glues, and synthetic PGMA adhesive. Tensile testing
on wet wood showed a slight increase in the bonding strength of BSA adhesive, a considerable decrease in the bonding strength
of cyanoacrylate glue, and negligible adhesion of PGMA. Tests performed on BSA samples demonstrate that initial BSA concentration
and final water content have a significant effect on the stress–strain behavior of the samples. 相似文献
95.
Nimrod Yavo Alaric D. Smith Ori Yeheskel Sydney Cohen Roman Korobko Ellen Wachtel Peter R. Slater Igor Lubomirsky 《Advanced functional materials》2016,26(7):1138-1142
Classical electrostriction, describing a second‐order electromechanical response of insulating solids, scales with elastic compliance, S, and inversely with dielectric susceptibility, ε. This behavior, first noted 20 years ago by Robert Newnham, is shown to apply to a wide range of electrostrictors including polymers, glasses, crystalline linear dielectrics, and relaxor ferroelectrics. Electrostriction in fluorite ceramics of (Y, Nb)‐stabilized δ‐Bi2O3 is examined with 16%–23% vacant oxygen sites. Given the values of compliance and dielectric susceptibility, the electrostriction coefficients are orders of magnitude larger than those expected from Newnham's scaling law. In ambient temperature nanoindentation measurements, (Y, Nb)‐stabilized δ‐Bi2O3 displays primary creep. These findings, which are strikingly similar to those reported for Gd‐doped ceria, support the suggestion that ion conducting ceramics with the fluorite structure, a large concentration of anion vacancies and anelastic behavior, may constitute a previously unknown class of electrostrictors. 相似文献
96.
Paola Marzullo Sonya Vasto Silvestre Buscemi Andrea Pace Domenico Nuzzo Antonio Palumbo Piccionello 《International journal of molecular sciences》2021,22(22)
1,2,4-Oxadiazole is a heterocycle with wide reactivity and many useful applications. The reactive O-N bond is usually reduced using molecular hydrogen to obtain amidine derivatives. NH4CO2H-Pd/C is here demonstrated as a new system for the O-N reduction, allowing us to obtain differently substituted acylamidine, acylguanidine and diacylguanidine derivatives. The proposed system is also effective for the achievement of a reductive rearrangement of 5-(2′-aminophenyl)-1,2,4-oxadiazoles into 1-alkylquinazolin-4(1H)-ones. The alkaloid glycosine was also obtained with this method. The obtained compounds were preliminarily tested for their biological activity in terms of their cytotoxicity, induced oxidative stress, α-glucosidase and DPP4 inhibition, showing potential application as anti-diabetics. 相似文献
97.
98.
We investigated the electrical signatures of iron corrosion and mineral precipitation in angle cores from an Fe(0) barrier installation in operation for eight years. The real and imaginary parts of the complex electrical conductivity measured between 0.1 and 1000 Hz were 2-10 times higher (varying between cores) in the reacted zone at the upgradient edge of the barrier relative to less altered locations inside the barrier. Scanning electron microscopy identified iron surface alteration with the thickest corrosion rinds closest to the upgradient soil/iron interface. Surface area of iron minerals was also greatest at the upgradient interface, gradually decreasing into the cores. X-ray diffractometry identified precipitation of iron oxide/hydroxide, carbonate minerals, iron sulfide, as well as green rusts, with mineral complexity decreasing away from the interface. The electrical measurements correlate very well with the solid-phase analyses, and they verify that electrical methods could be used to assess or monitor iron corrosion and mineral precipitation occurring in Fe(0) barriers. 相似文献
99.
Objective
To characterise the relative amount and type of daily newspaper, local and national TV newscast, and national news magazine coverage of tobacco control issues in the United States in 2002 and 2003.Design
Content analysis of daily newspapers, news magazines, and TV newscasts.Subjects
Items about tobacco in daily newspapers, local and national TV newscasts, and three national news magazines in a nationally representative sample of 56 days of news stratified by day of week and season of the year, from 2002 and 2003.Main outcome measures
Story theme, tobacco topics, sources, story prominence, story valence (orientation), and story type.Results
Tobacco coverage was modest over the two‐year period as estimated in our sample. Only 21 TV stories, 17 news magazine stories, and 335 daily newspaper stories were found during the two‐year sampling period. Noteworthy results for the newspaper data set include the following: (1) government topics predominated coverage; (2) government action and negative health effects topics tended not to occur together in stories; (3) tobacco stories were fairly prominently placed in newspapers; (4) opinion news items tended to favour tobacco control policies, while news and feature stories were evenly split between positive and negative stories; and (5) tobacco coverage in the southeast, which is the country''s major tobacco producing region, did not differ from the rest of the country.Conclusion
Results suggest mixed support in news coverage for tobacco control efforts in the United States. The modest amount of news coverage of tobacco is troubling, particularly because so few news stories were found on TV, which is a more important news source for Americans than newspapers. When tobacco was covered, government themed stories, which often did not include mentions of negative health effects, were typical, suggesting that media coverage does not reinforce the reason for tobacco control efforts. However, some results were encouraging. For example, when newspapers did cover tobacco, they accorded the stories relatively high prominence, thus increasing the chance that readers would see tobacco stories when they were published. 相似文献100.