Materials Literature
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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…
In this paper, we report an effective-medium theory on the remanence of magnetically interacting particles to demonstrate the effect of intergranular magnetostatic interactions on the remanence enhancement of materials, which agrees excellently with micromagnetic simulations. A dimensionless parameter \ensuremath{\lam…
Single crystals of LaSeTe(2) have been prepared by reaction of the elements in a LiCl/RbCl flux at 970 K for seven days. Satellite reflections observed in diffraction experiments indicate the presence of an incommensurate lattice distortion, which is of the charge-density-wave (CDW) type. The modulated structure has b…
Abstract The values of the percentage crystallinity, melting temperature, birefringence, and cross‐sectional area of ultrahigh molecular weight polyethylene (UHMWPE)/low MWPE (LMWPE) as‐prepared fiber specimens are reduced consistently as the formation temperatures decreased from 60 to 0°C. Much more sparse structures…
A wall-jet flow cell was used to study reduction at AA2024-T3. In buffered -saturated solution the current density was 2% of the diffusion-limited value and relatively stable with time. In unbuffered solution the current density was 25-50% of the diffusion-limited value. The higher currents under unbuffered conditions…
Abstract The radiation grafting of silk with methacrylamide (MAA) was studied using an electron‐beam (EB) irradiation technique. Two irradiation processes, preirradiation and coirradiation, were compared, and some factors affecting the degree of grafting were investigated. The radiation crosslinking of silk with dimet…
Abstract A set of high‐molecular‐weight, new, side‐chain liquid‐crystalline polyethers was obtained by chemical modification of poly(epichlorohydrin) with potassium 3,4,5‐tris[4‐( n ‐dodecan‐1‐yloxy)benzyloxy]benzoate. The degree of modification depended on the reaction conditions and ranged from 39 to 58%. The highes…
Abstract Electron beam (EB) irradiation of polyvinyl chloride (PVC) was carried out in the presence of three different ethylene–vinyl acetate copolymers (EVA). The mechanical properties of the original and irradiated blends were tested. The gel content measurement, chlorine loss upon electron irradiation, and gel perm…
Two types of equilibrium core structures (denoted symmetric and asymmetric) for $1/2a〈111〉$ screw dislocations in bcc metals have been found in atomistic simulations. In asymmetric (or polarized) cores, the central three atoms simultaneously translate along the Burgers vector direction. This collective displacement of…