Materials Literature
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Abstract Polymer formation from THPOH‐urea, THPOH‐dichloropropanol‐urea, and THPC‐urea was studied. Order and rate of urea addition were shown to influence insoluble polymer yields as well as polymer structure. The polymers were characterized by elemental analyses and infrared spectroscopy, and predominant structures…
The action of NbCl5 on a porphyrin (H2L) followed by hydrolysis leads to a complex [(NbL)2O3]. When treated with acetic acid this complex in turn yields a metalloporphyrin of general formula [NbL(O)(O2CMe)]·xMeCO2H. The crystal structures of [{Nb(tpp)}2O3]·4C2H4Cl2(1b) and [Nb(tpp)O(O2CMe)]·MeCO2H (2b)(tpp is the dian…
The observation of spin–spin coupling between 89Y and 31P nuclei in the complex [Y(S2PR2)4]–, R = OEt, is interpreted as evidence for covalent bonding. The magnitude of the reduced coupling constant 2KY–P is of the same order as 2KRh–P and 2KPt–P in [Rh(S2PR2)3] and [Pt(S2PR2)2] indicating similarity in the covalent c…
Electronic energy transfer from the lowest triplet state of triphenylene to the terpositive aquated lanthanide ions, Pr3+, Nd3+, Sm3+, Er3+ and Tm3+ in alcohol glasses at 77 K was investigated. On the basis of spectral overlap calculations and the fitting of the observed donor phosphorescence decays to the decay funct…
Upon charge-transfer excitation (λirrad= 228 nm)[Ru(CN)6]4–, [Mo(CN)8]4–, and [W(CN)8]4–, dissolved in CHCl3, are photo-oxidized to [Ru(CN)6]3–(ϕ= 0·49), [Mo(CN)8]3–(ϕ= 0·40), and [W(CN)8]3–(ϕ= 0·37).
The cavitation-induced deformation and erosion of metals of the three common crystal structures, face centered cubic, body centered cubic, and hexagonal close packed (fcc, bcc, hcp), have been investigated. It is shown that the shock-loading conditions encountered by the metal during cavitation enhances the effects of…
Abstract The limits of neodymium substitution for yttrium in (Y, Nd)Al 3 (BO 3 ) 4 crystals in preparation from solutions in molten potassium trimolybdate have been studied. The maximum neodymium concentration in the crystals was 72 at.%, this corresponding to the ratio Nd:Y = 1 in the solution. When this ratio exceed…
The role of lead in free-machining brass has been studied by calculating the temperatures formed in the primary and secondary shear zones of chip formation and by examining, in a scanning electron microscope, the structure of chips from cutting experiments. The calculations show that the temperatures in the primary zo…
The Grandjean-Friedel-Cano wedge geometry is used to produce well controlled edge dislocation patterns in ordered latexes. Due to the strain field, the color of the Bragg reflected light is found to be modified, making the dislocations easily visible in a metallurgical microscope. An estimate of the elastic energy sto…
Silk, which has been utilized widely as an excellent textile fiber, has also been used as a good material for research, as a typical protein. Numerous studies on silk, carried out continuously over a period of more than one century, have contributed not only to the improvement of production process and quality of raw…
Analysis of a thermoelectric generator (TEG) in an ocean thermal energy conversion (OTEC) application is presented. An analytic model is developed for describing the heat exchanger-TEG interactions. This model is used to illustrate limitations of applying conventional fixed junction temperature assumptions to systems…
Abstract 1 J ( 15 N 13 C) values obtained from FT 13 C NMR spectra were measured for a number of 15 N‐enriched aniline derivatives and are found to exhibit varying degrees of dependence on the nature of the ring substituent. Theoretical calculations of 1 J ( 15 N 13 C) values for representative members of the systems…
Recent experiments on developmental fast-flux test facility (FFTF) cladding (20 percent cold-worked Type 316 stainless steel) have extended the data base to a fast neutron fluence of 8.4 × 1022 neutrons (n)/cm2 (E > 0.1 MeV). The specimens were irradiated in the experimental breeder reactor-II (EBR-II) at tempe…
This paper summarizes the r esults of 3 exploratory investigations: (1) radiant heattransfer, both solar and infrared, into water, (2) heat conduction through metals, and (3) melting of a heterogenous system. An ultrasonic cleaning bath having a frequency of SO kHz was used in the radiant heat transfer experiments wit…
To establish the mechanical response of Zircaloy cladding under thermal shock conditions typical of hypothetical loss-of-coolant accident (LOCA) situations in light-water reactors (LWRs), cladding specimens were ruptured in steam during transient heating (10 K/s), oxidized at maximum temperatures between 1140 and 1770…
The mechanism of emptying and filling of pore domains along the adsorption as well as the desorption boundary curve of the hysteresis loop was studied by the determination of a V–S curve derived from the tangents to primary scanning curves immediately after a pressure reversal at the boundaries of the hysteresis regio…
Luminescence from a wide range of NaCl crystals of different purity has been excited by electrons and ion beams. Despite the range of crystal quality there are many similarities between the spectra excited under similar conditions. At both 77 and 300 K there is strong emission near 2.4 eV in all samples but the so cal…
P, V, T equations of state were theoretically constructed for the orthorhombic (o-PE) and triclinic modifications of polyethylene (t-PE). Helmholtz free energies A at arbitrary temperatures were calculated for the lattices with various unit cell dimensions. Contribution of the zero-point energy (for T=0 K) as well as…
Abstract Es gelang, vierwertiges Neodym durch Einbau in Wirtsgitter mit Perowskitstruktur zu stabilisieren. Als Wirtsgitter wurden BaCeO 3 , BaPrO 3 , BaThO 3 und BaZrO 3 eingesetzt. Die Präparation erfolgte durch Glühen der entsprechenden Oxide an Luft bei 1 250–1400°C. Röntgenographische und analytische Charakterisi…
By simple steric considerations, we intend to show that the herringbone packing, which is characteristic of the ordered smectic phases, is governed by geometrical factors, contrary to the usually admitted theories which are based on dipolar interactions.