The synthesis of porphins and related macrocycles
R. L. N. Harris, A. W. Johnson and I. T. Kay, Q. Rev. Chem. Soc., 1966, 20, 211 DOI: 10.1039/QR9662000211
Materials Literature
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Dielectric study of the transition temperature regions for poly (vinyl chloride) and some chlorinated poly(vinyl chlorides)
Abstract Audio frequency dielectric constant data versus temperature data for poly(vinyl chloride) exhibit a high temperature (glass) transition which becomes steeper and reaches higher values as the frequency is reduced. The same trend is demonstrated for a series of chlorinated poly(vinyl chlorides) although the tra…
Inert Gases in Metals
The study of inert-gas behaviour with respect to metals has a history almost as long as that of the inert gases themselves, reference to the permeation of helium through a number of metals having been made in 1897, less than two years after the isolation of the new element.
The electron-spin resonance spectrum of a phosphorane radical cation trapped in a crystalline matrix
X-Irradiation of single crystals of carboxymethyltriphenylphosphonium chloride produces the corresponding oriented phosphorane radical-cation Ph3[graphic omitted]ĊH·CO2H. The spectrum has been analysed to yield the hyperfine coupling tensors of the 1H and 31P nuclei and the g-tensor. These values are discussed in term…
Physiological Studies of the Boron Requirement of the Diatom,Cylindrotheca fusiformisReimann and Lewin
Cylindrotheca fusiformis, a marine pennate diatom, requires boron for growth both in the light and in the dark. A synthetic saline nutrient medium and plastic containers were used to demonstrate the boron requirement. A boron concentration of at least 0.5 ppm supports the maximum growth-rate, with a generation time of…
Structure of B 2 O 3 and Binary Aluminoborate Melts at 1600°C
Viscosity and density data were obtained up to 1700°C for a series of binary aluminoborate melts that contained as much as 15 mole% (∼21 wt%) Al 2 O 3 and up to 1620°C for pure molten B 2 O 3 . Large expansion coefficient decreases and a slight activation energy increase for B 2 O 3 above 1400°C suggested a tightening…
The Parabolic Oxidation Kinetics of Niobium
The rate of growth and properties of the first layer of compact to form are important for elucidation of the oxidation reaction for niobium. It was found possible to maintain this oxide in contact with the metal for sufficient time in the temperature range 720°–825°C to make measurements of its growth rate at various…
Electrical Pinch in Elastically Deformed Germanium
Abstract The phenomena accompanying the flow of an electric current through uniaxially compressed plates of intrinsic Ge are investigated. The plates are cut with definite orientations relative to the main crystallographic axes so that the directions of the current and field do not coincide. Under these conditions tra…
The System V204-V205 Phase Diagram and Some Physical Properties of V6013, V307 and V205
V204～V206系平衡状態図のうち,V～V204系は多くの研究者によって詳細に研究されているが,V204～V205系については,完全な平衡状態図は完成されていな炉。そこで著者らは,X線解析と示差熱分析とを用いて,V204～V205系状態図を決定した.その結果,V204～V205の中間に,V8O13,V307の二相が存在し,それぞれ710°,680℃の包晶温度を持つことを確認した。またV307,V205は非常に狭い固溶領域を持つことがわかった。さらにV6O13,V307,V205の比抵抗と帯磁率を測定して比較検討した。新しい相V307は,-200°～+200℃の温膵範囲で,常磁性を示し,-200°～0℃の温度範囲で・他の相より大き…
{10\bar11} Transformation Twins in Titanium
{10\bar11} transformation twins, produced in the martensite of commercially pure titanium, have been investigated by means of transmission electron microscopy and discussed in relation to the character of the martensitic transformation. The results are as follows: (1) The twins have a thickness of 250∼3000 Å, and they…
Electron spin resonance spectra of [Cr(CN) 5 (NO)] 3– , [Cr(NO)(NH 3 ) 5 ] 2+ , and [Cr(NO)(H 2 O) 5 ] 2+
Electron spin resonance (e.s.r.) spectra of dilute fluid and rigid aqueous solutions of [Cr(CN)5NO]3–, [Cr(NO)(NH3)5]2+, and [Cr(NO)(H2O)5]2+ have been measured. [Cr(NO)(H2O)5]2+ appears axially symmetric with g⊥ considerably larger than g∥; 53Cr and 14N hyperfine structure has been observed for this complex. In contr…
Anodic deposition of NiOOH from nickel acetate solutions at constant potential
Potentiostatic methods have been used to investigate the kinetics of electrodeposition of NiOOH from buffered acetate solutions. The dependence of the rate constants governing crystal growth upon potential, pH, and Ni2+ ion concentration has been measured. The initial formation of a very thin oxide layer by three-dime…
Ultrasonic Treatment of Specimens in the Electron Microscope
A method and technical details are described for direct observation of effects of high amplitude ultrasonic stress waves on dislocations in metal crystals. The technique combines, for the first time, ultrasonic treatment at high acoustic energy densities (up to 109 ergs/cm3 at frequencies between 30 and 100 kc), obser…
5—FRICTIONAL FORCES IN COTTON AND REGENERATED CELLULOSIC FIBRES
Inter-fibre frictional forces, F, corresponding to normal loads, R, of up to 300 g, experimentally determined for a large number of fibres, mostly cottons, rayons, and polynosic rayons, conform to a general expression of the form F = αRn . The parameters α and n are, however, shown to be interdependent, correlations a…
Main Characteristics of Piezo-Magnetization and Their Qualitative Interpretation
Major characteristics of observed effects of uniaxial compression upon magnetization of rocks and assemblages of magnetic minerals are summarized as follows: -(a) uniaxial compression in a magnetic field results in a decrease of magnetization; (b) removal of the magnetic field in presence of the compession causes a de…
The structure of mercuri-iodide ions. I. Trimethylsulphonium mercuritriiodide (CH3)SHgI3
electrostatic forces. The repulsions terms amount to about 10-15% of the lattice energy and cannot be neglected. It should be pointed out the variation of the oxygen parameter has not been taken into account as has already been done by Verwey, de Boer & van Santen (1948), who already give the energy values for 1 and 2…
Specific heat studies of transition and relaxation behavior in polymers
Abstract Specific heat studies of polymers are reviewed within the framework of Buyer's classification: ( a ) melting transition ( T m ); ( b ) glass transition ( T g ); ( c ) subglass relaxation ( T < T g ); and ( d ) intermediate relaxation ( T g < T < T m ). The melting transition is readily apparent in sp…
The meso-reactivity of porphyrins and related compounds. Part II. Halogenation
The α-chloro-, αγ-dichloro-, and αβγδ-tetrachloro-derivatives of octaethylporphyrin have been prepared by direct halogenation of the porphyrin. Chlorination of octaethylchlorin gives the corresponding γ-chloro- and γδ-dichloro-chlorins; dehydrogenation of the former with 2,3-dichloro-5,6-dicyanobenzoquinone leads to α…
Infrared study of cation ordering and clustering in some (Fe,Mg) amphibole solid solutions
R. G. J. Strens, Chem. Commun. (London), 1966, 519b DOI: 10.1039/C1966000519B
Passivation and pitting characteristics of zinc
The passivation of a zinc electrode has been studied both by galvanostatic and potentiostatic methods in boric acid-sodium hydroxide buffer solutions. After addition of chloride ion, the characteristics of pitting corrosion have been investigated. The results indicate that pits form only on a passive surface and that…