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51.
Xinnan Zhang Gang‐Chi Chen Andrew Collins Solomon Jacobson Paul Morganelli Yadunandan L. Dar Osama M. Musa 《Journal of polymer science. Part A, Polymer chemistry》2009,47(4):1073-1084
New thermosetting materials were developed for reworkable adhesive applications by introducing acetal ester groups as thermally degradable linkages into maleimide compounds. The synthesis of compounds containing maleimide functionality and acetal ester linkages was conducted by a one‐step neat reaction from commercially available materials. The polymerization process and thermal degradation of the synthesized materials were studied. It was found that the acetal ester linkage degraded rapidly above 225 °C, and introduction of this linkage into the adhesive formulation led to improved reworkability of adhesively bonded substrates. A mechanism for reworkability was proposed based on the insight provided by experimental and modeling work. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1073–1084, 2009 相似文献
52.
E. W. Scott J. F. Treon A. v. Grosse E. J. Rosenbaum und H. F. Jacobson 《Fresenius' Journal of Analytical Chemistry》1941,122(1-2):78-79
Ohne Zusammenfassung 相似文献
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Cyclotetrabenzoin: Facile Synthesis of a Shape‐Persistent Molecular Square and Its Assembly into Hydrogen‐Bonded Nanotubes
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Qing Ji Ha T. M. Le Dr. Xiqu Wang Dr. Yu‐Sheng Chen Dr. Tatyana Makarenko Prof. Allan J. Jacobson Prof. Ognjen Š. Miljanić 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(48):17205-17209
Cyanide‐catalyzed benzoin condensation of terephthaldehyde produces a cyclic tetramer, which we propose to name cyclotetrabenzoin. Cyclotetrabenzoin is a square‐shaped macrocycle ornamented with four α‐hydroxyketone functionalities pointing away from the central cavity, the dimensions of which are 6.9×6.9 Å. In the solid state, these functional groups extensively hydrogen bond, resulting in a microporous three‐dimensional organic framework with one‐dimensional nanotube channels. This material exhibits permanent—albeit low‐porosity, with a Langmuir surface area of 52 m2 g?1. Cyclotetrabenzoin’s easy and inexpensive synthesis and purification may inspire the creation of other shape‐persistent macrocycles and porous molecular crystals by benzoin condensation. 相似文献
57.
Water cluster anions, (H(2)O)(N)(-), are examined using mixed quantum/classical molecular dynamics based on a one-electron pseudopotential model that incorporates many-body polarization and predicts vertical electron detachment energies (VDEs) with an accuracy of ~0.1 eV. By varying the initial conditions under which the clusters are formed, we are able to identify four distinct isomer types that exhibit different size-dependent VDEs. On the basis of a strong correlation between the electron's radius of gyration and its optical absorption maximum, and extrapolating to the bulk limit (N → ∞), our analysis supports the assignment of the "isomer Ib" data series, observed in photoelectron spectra of very cold clusters, as arising from cavity-bound (H(2)O)(N)(-) cluster isomers. The "isomer I" data reported in warmer experiments are assigned to surface-bound isomers in smaller clusters, transitioning to partially embedded isomers in larger clusters. The partially embedded isomers are characterized by a partially formed solvent cavity at the cluster surface, and they are spectroscopically quite similar to internalized cavity isomers. These assignments are consistent with various experimental data, and our theoretical characterization of these isomers sheds new light on a long-standing assignment problem. 相似文献
58.
Manoj Yadav Wenquan Gong Allan J. Jacobson 《Journal of Solid State Electrochemistry》2011,15(2):293-301
Oxygen gas can be electrochemically separated from ambient air with very high purity and compressed by using a solid-electrolyte
ion-transport membrane. An electrolyte with high ionic conductivity such as gadolinium-doped ceria (CGO) and mixed conducting
electrodes are used to construct the electrochemical cell. To achieve high oxygen flux, the electrodes must exhibit very fast
electrode kinetics. Here, we report the performances of mixed conducting PrBaCo2O5 + x
and NdBaCo2O5 + x
electrodes in oxygen separation in a planar CGO electrolyte-supported cell. The properties of the electrode materials were
evaluated using potentiostatic and potentiodynamic measurements and alternating current impedance spectroscopy. The oxygen
flux was also measured using gas chromatography to confirm the absence of gas leaks. The electrodes demonstrated very low
polarization resistances as a result of very high cathodic and anodic reaction rates at temperatures of 600–800 °C. High oxygen
gas flow rates were observed on applying potentials up to 1 V with an almost linear relationship between the applied potential
and the molar flow rate of oxygen gas. 相似文献
59.
This paper generalizes the sequential stochastic assignment problem, involving the assignment of workers to sequentially arriving
jobs, by introducing uncertainty into the job value distribution. Three estimators are presented that address various levels
of uncertainty while simultaneously improving worker assignments. Specifically, each estimator is designed to utilize the
unbiased and consistent properties of the sample mean to estimate the expected job value, while suppressing high variance
effects during start-up. The key contribution is that closed-loop decision policies involving past job value observations
can responsively adapt to changing environments and improve the overall reward resulting from pairing workers with jobs. Examples
of applications that can benefit from these results include aviation passenger screening and the real estate market, as well
as applications of the stochastic knapsack problem. 相似文献
60.