Materials Literature
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Sixteen 1:1 methanesulfonic acid–N-oxide systems were studied as a function of the basicity of the N-oxides. The observed IR continua demonstrate that a single minimum proton potential is shifted, with increasing basicity, from the acid to the N-oxide. The largest proton polarizability is attained with the system that…
The hydrothermal reaction of a mixture of vanadyl acetylacetonate (VO(acac)(2)), Na(2)SO(4), 2,2'-bipyridine (2,2'-bpy), and H(2)O for 48 h at 160 degrees C gives brown crystals of [V(2)O(2)(OH)(2)(SO(4))(2,2'-bpy)(2)] (1) in 70% yield. The structure of 1 consists of ribbons constructed from the infinite inorganic cha…
The protonation constants of the ligand 1,7-dicarboxymethyl-1,4,7,10-tetraazacyclododecane (DO2A) were re-determined by the potentiometric pH titration method (log K 10.94, 9.55, 3.85, 2.55) and the macrocycle ring protonation sites have also been confirmed by NMR techniques to be the secondary amine nitrogen atoms. T…
Sulfonated manganese(III) tetraphenylporphyrin supported on poly(4-vinylpyridine), Mn(tpps)–PVP, can act as an efficient heterogeneous catalyst for alkene epoxidation and alkane hydroxylation by sodium periodate.
This paper deals with the plasma surface treatment of polymers in a low frequency bell jar reactor with non-symmetrical configuration of electrodes. This special configuration of electrodes simulates the industrial surface treatment of polymers i.e. very short treatment times (milliseconds to a few seconds). The physi…
By using an electrostatic probe located close to the triple junction on the cathode surface, we have conducted real-time observations of the change in electric field due to surface charging of an insulator in vacuum. A cylindrical sample made of polymethylmethacrylate (PMMA) or Al/sub 2/O/sub 3/ has been exposed to HV…
The study was conducted to determine whether living or killed cell polyphosphate bodies (PPB) would sequester more of several heavy metals. Living and heat- or glutaraldehyde-killed cells were exposed to 20 ppm of Zn, Pb, Mn and Al. Air-dried cells on Formvar-coated grids were first observed in the transmission electr…
The upper critical temperature ${T}_{c2}$ for the phase transition between the cholesteric phase ${(N}^{*})$ and the twist grain boundary $C$ phase with the layer inclination tilted to the pitch axis $({\mathrm{TGB}}_{\mathrm{Ct}})$ in thermotropic liquid crystals is determined by the mean field Chen-Lubensky approach…
It has been shown that the high catalytic activity of a Dawson-type heteropolyacid for gas-phase methyl tert-butyl ether synthesis at low temperatures is attributable to its amorphous secondary structure, which brings about a flexible pseudo-liquid phase and facilitates rapid absorption and desorption of molecules.
Cycles of wetting and blow-drying were applied to hair fibers and resulted in the formation of multiple cracks on the hair cuticles. The peculiarity of these cracks was that they always appeared aligned parallel to the longitudinal axis of the hair fiber. The cracks appeared to be initiated at the end of the cuticles…
Carbon onions have been produced in a transmission electron microscope by electron irradiation of amorphous carbon in the presence of Pd clusters. High-resolution electron microscopy revealed structural changes of the onion surface, and atom clouds were observed at the pentagonal vertices. In some onions, Pd atoms wer…
The deposition of passive diamond layers of thickness comparable to 1 μm directly within integrated electronic and optoelectronic circuits and microelectromechanical systems promises to improve their figures of merit, in particular those influenced by heat conduction. This application of diamond poses major challenges…
A new carbon/carbon (C/C) composite was successfully produced at room temperature by drawing a silver tube containing carbon nanotubes as the fiber material and nanocrystalline carbon 60 (C60) as the matrix. Fine structures of the composite were examined by transmission electron microscopy (TEM) and the mechanical pro…
Cellulose triacetate prepared from bacterial cellulose of Acetobacter xylinum subsp. sucrofermentans BPR3001A showed a higher degree of polymerization and higher mechanical strength than that from the cotton linter. The fine fibrils of bacterial cellulose required only a short time for acetylation which preserved the…
In the Cu-Zr system, especially between 0.25 < x(Zr) < 1, experimental liquidus points are missing and many doubts arise concerning the invariant points. In 1986, Kneller et al. [1] pointed out the existence of three phases and two eutectoid reactions which had not yet been reported. This work has been questione…
The structure of oxide glass consists of relatively well defined oxide polyhedra, with significant disorder in the linkages between these groups. We review recent progress in understanding these structures, including the length scales over which they exist, and how they may be modified chemically. We discuss two prima…
Naphtho[2,1-d:6,5-d′]bis([1,2,3]dithiazole) NT, prepared by a ‘double Herz’ condensation of 2,6-diaminonaphthalene with S2Cl2, can be electrooxidized to the conductive, π-stacked mixed valence salt [NT]3[BF4]2.
Sonoluminescence has been used to excite the water soluble acid–base fluorescent indicator trisodium 8-hydroxy-1,3,6-pyrenetrisulfonate, leading to light emission (sonophotoluminescence) from the dye.
Upconversion fluorescences of the green 4 S 3/2 → 4 I 15/2 and red 4 F 9/2 → 4 I 15/2 transitions of the Er 3+ ion are studied for Yb 3+ ‐ and Er 3+ ‐codoped sodium germanate, potassium tantalum gallate, and barium tellurite glasses by InGaAs laser‐diode pumping. The phonon energies of the host glasses are determined…
3,6,10-Tri(carboxymethyl)-3,6,10-triazadodecanedioic acid (H5L), was synthesized and its protonation constants were determined by potentiometric titration in 0.10 mol dm–3 Me4NNO3 and by NMR pH titration at 25.0 ± 0.1 °C. Stability and selectivity constants have been measured to evaluate the possibility of using the c…