Materials Literature
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The theoretical model is fully developed and the test rig is designed for the measurements of microwave parameters of unclad and laminated dielectric substrates. The geometry of the electromagnetic field in the resonator allows dielectric measurements with electric field component orthogonal to the sample surface. The…
We compare two different approaches to investigations of many-electron systems. The first is the Hartree-Fock (HF) method and the second is the Density Functional Theory (DFT). Overview of the main features and peculiar properties of the HF method are presented. A way to realize the HF method within the Kohn-Sham (KS)…
The multiscale Monte-Carlo algorithm outlined in Bai and Brandt[1] is applied to a simple model of the polypeptide backbone. Effective coarse level Hamiltonians are derived by a fast Newtonian iterative scheme. The coarse Hamiltonian parameters are adjusted so that local structural properties have the same value in bo…
The title compound, lead bismuth calcium sodium phosphate, Pb(4.6)Bi(0.4)Ca(2.6)Na(2.4)(PO(4))(6) crystallizes in the apatite structure type, with vacancies in sites 2a or 2b that are normally occupied by anions. The fact that the Bi and Pb ions are mainly localized in the 6h sites confirms the electron lone-pair infl…
Aromatic hydrocarbon vapors adsorb to the air/water interface and are transported by wet deposition processes via fog, mist, and rain. A falling droplet apparatus was used to study the adsorption and uptake of naphthalene vapor on water droplets with diameters ranging from 14 to 200 microm. Uptake of naphthalene vapor…
Quantitative image analysis of transmission electron micrographs (TEM) of poly(ethylene terephthalate) (PET) thin sections was performed and compared to data obtained by small-angle X-ray scattering (SAXS) on the same samples. Different methods to analyze the TEM images are presented, and the results are compared with…
A trisilanol derivative of polyhedral oligomeric silsesquioxanes (POSS), trisilanolisobutyl-POSS, has recently been reported to form stable monolayers at the air/water interface. Moreover, the trisilanolisobutyl-POSS monolayer undergoes a nonequilibrium structural transition (collapse) around a surface pressure of Rho…
A series of diacetylene-containing polymers were prepared by oxidative coupling polymerization of 9,9-bis(4-propargyloxyphenyl)fluorene and dipropargyl 4,4‘-(hexafluoroisopropylidene)diphthalimide. The polymers had molecular weights of 42 000−235 300 and polydispersity indices of 1.1−1.8 as determined by gel permeatio…
Highly photoluminescent glass was prepared by embedding water-soluble nanocrystals in a glass matrix using a novel sol-gel process. Thiol-stabilized CdTe nanocrystals and aminopropyltrimethoxysilane were found to be the best combination in the preparation. The synthesis process had to be optimized to avoid nanocrystal…
Gallium trichloride, GaCl 3, reacts with the in situ prepared sodium salt of an aminoalkoxide or iminoalkoxide, denoted as NaL, to give the disubstituted compounds GaL 2 Cl, where L = OC(CF 3 ) 2 CH 2 NMe 2 ( 1 ), OC(CF 3 ) 2 CH 2 C(Me) NMe ( 2 ). Single-crystal X-ray diffraction studies on 1 and 2 indicated the forma…
[structure: see text] A novel (two-zone process with different spin-state channels) mechanistic picture for the Jacobsen-Katsuki reaction is presented that provides insight into the still elusive understanding of the epoxidation mechanism. For the first time, we show that the salen moiety of the catalyst can be explic…
Bulk condensation polymerizations of adipic acid and octanediol, catalyzed by Candida antartica Lipase B (CALB), were investigated. The polymers formed by 8 and 24 h polymerizations using CALB immobilized on Accurel and Lewatit had similar molecular weights (e.g., M n at 24 h ≈15 000). CALB “free” of the immobilizatio…
The controlled decomposition of the sandwich-type polyoxometalates K(12)[(M(OH(2))(2))(3)(A-alpha-PW(9)O(34))(2)] (where M = Mn(II) or Co(II)) in 0.5 M NaCl yields a new family of transition metal substituted POMs of the general formula [((MOH(2))M(2)PW(9)O(34))(2)(PW(6)O(26))](17)(-) (where M = Mn(II) (1Mn) or Co(II)…
We demonstrate a silicone damping elastomer with a constant high damping performance ( tan δ = E ‘ ‘/ E ‘ ≈ 0.3 where E ‘ and E ‘ ‘ are the storage and loss Young's moduli, respectively) over a broad temperature range of 180 °C (−30 °C < T < 150 °C) utilizing a slow viscoelastic relaxation of an irregular network stru…
The labeling of biological species using dyes has become common practice to aid in their detection, and immediate positive identification of specific dyes in high dilution is a key requirement. Here the detection by surface-enhanced resonance Raman scattering (SERRS) of eight commercially available dye labels (ROX, rh…
Highly monodisperse, 1−2-nm diameter Au nanoparticles were prepared using poly(amidoamine) (PAMAM) dendrimers as templates. The synthesis is carried out in water, takes less than 30 min, and requires no subsequent purification. Au nanoparticles having diameters of 1.3 ± 0.3 and 1.6 ± 0.3 nm were obtained when 55 and 1…
We present measurements of photoluminescence decay dynamics from single colloidal CdSe quantum dots. We find that the decays fluctuate in time with decay rates that correlate with time-averaged emission intensities. Moreover, the decays measured by selecting only those photons collected while the single quantum dot em…
thiophene] (1) and poly [3-(12-bromododecyl)thiophene] (2) were synthesized by chemical polymerization of their respective monomers, 3 and 4, using FeCl 3 . NMR spectroscopy showed 81% of head-to-tail couplings and GPC showed M n = 51,500 and 91,100 with PDIs of 5.2 and 1.7 for 1 and 2, respectively. Conductivities of…
Abstract The volume strain changes of plasticized poly(vinylidene fluoride) during tensile and creep tests were characterized. A negative volume strain was observed. This phenomenon was ascribed to compaction taking place during mechanical testing, which further delayed the onset of plastic instability and, therefore,…
Polymer-dispersed liquid crystal (PDLC) films of 4-cyano-4‘-pentylbiphenyl (5CB) were fabricated between two quartz substrates, the surfaces of which had been modified with the self-assembled monolayers (SAMs) of CH 3 −(CH 2 ) 17 −Si(OMe) 3 ( 1 ), HS−(CH 2 ) 10 −Si(OEt) 3 ( 2 ), and NC−(CH 2 ) 11 −Si(OEt) 3 ( 3 ). The…