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Author: A. F. Armington Publisher: ISBN: Category : Boron Languages : en Pages : 12
Book Description
In this paper the present methods of boron preparation are discussed with emphasis on the iodide intermediate. Several methods of boron triiodide preparation were investigated, the most satisfactory method being the preparation from the elements. A yield of 60 pct based on iodine is found for this method. Zone-refining, sublimation, distillation, and fractionalrecrystallization results are given for the boron triiodide, with distillation producing the best results. Several methods of decomposition are also discussed. The purity of the resulting iodide boron approximates the purity of the best available bromide boron. (Author).
Author: A. F. Armington Publisher: ISBN: Category : Boron Languages : en Pages : 12
Book Description
In this paper the present methods of boron preparation are discussed with emphasis on the iodide intermediate. Several methods of boron triiodide preparation were investigated, the most satisfactory method being the preparation from the elements. A yield of 60 pct based on iodine is found for this method. Zone-refining, sublimation, distillation, and fractionalrecrystallization results are given for the boron triiodide, with distillation producing the best results. Several methods of decomposition are also discussed. The purity of the resulting iodide boron approximates the purity of the best available bromide boron. (Author).
Author: Alton F. Armington Publisher: ISBN: Category : Boron Languages : en Pages : 0
Book Description
In this paper the present methods of boron preparation are discussed with emphasis on the iodide intermediate. Several methods of boron triiodide preparation were investigated, the most satisfactory method being the preparation from the elements. A yield of 60 pct based on iodine is found for this method. Zone-refining, sublimation, distillation, and fractionalrecrystallization results are given for the boron triiodide, with distillation producing the best results. Several methods of decomposition are also discussed. The purity of the resulting iodide boron approximates the purity of the best available bromide boron. (Author)
Author: J. T. Buford Publisher: ISBN: Category : Languages : en Pages : 78
Book Description
Ultrapure boron was produced via the boron triiodide intermediate. The BI3 was synthesized from crude elemental boron and C.P. grade iodine at various temperatures. A conversion efficiency of 56% was obtained using a charge of -4 +6 mesh boron at a temperature of 900-950C. Purification of the boron triiodide was performed by distillation in a 30 plate Oldershaw distillation apparatus, by batch zoning of the BI3 matrix, and by vacuum distillation. Thermal decomposition of the distilled BI3 produced boron with approximately 50 ppm carbon as the major impurity. The carbon impurity was measured by a gas chromatographic technique. Boron was crystallized for electrical measurements by vacuum zoning, using induction heating and by melting in a high pressure resistance heated furnace. Using this same high pressure equipment the synthesis of boron phosphide, boron arsenide and boron antimonide was studied. (Author).
Author: G.V. Samsonov Publisher: Springer Science & Business Media ISBN: 3642666205 Category : Science Languages : en Pages : 666
Book Description
V. I. MATKOVICH During the meeting of the International Symposium on Boron held in October, 1972 in Tbilisi, U.S.S.R., the idea was proposed to assemble a review of boron and refractory borides by the specialists present. The advantages of such a work were immediately apparent. Such diverse applications of borides as in protective armor, nuclear reactors, coat ings, reinforcement, etc. can hardly all be presented in sufficient detail by a single author. On the other hand it was also recognized that with so much specialization, some areas of interest may not be covered. Within the last decade or two a number of areas have been developed in which the use of refractory borides is growing and improvements are being actively explored. Thus, a number of borides have considerable potential as reinforcing material for plastics or light metals, though only boron fibers have been firmly established up to the present. Ap plication of flakes and films for two-dimensional reinforcement appears attractive, although the high cost of materials and development repre sents a considerable barrier. A number of borides have been used to manufacture lightweight protec tive armor. In this area relatively fast changes seem to be taking place as improvements in performance and weight are made. Boron carbide has found considerable use in this application and new developments exploit the light weight of beryllium borides.
Author: Edward A. Lewis Publisher: ISBN: Category : Error analysis (Mathematics) Languages : en Pages : 96
Book Description
Certain fundamental geometric properties of hyperbolas and ellipses on the surface of a sphere are developed. A first-order theory is then presented for the random errors in the location of a point on a spherical earth, by the intersection of spherical hyperbolas physically determined by a time difference technique in which the individual errors are 'normally' distributed and uncorrelated. Two cases are treated: (a) Four time-measuring stations working as two independent pairs, and (b) Three time-measuring stations working on a common time-base. In both cases, the contours of equal error probability density are shown to be ellipses and their properties are discussed. In both cases the distribution of radial error without regard to direction is given by a generalized distribution function which contains the Rayleigh distribution as a special case. Using the general form, the most probable mean, root mean square, and median radial errors are obtained. The results are adaptable to include errors in ordinary direction finders as well as those of the hyperbolic type. Numerical examples are included. (Author).
Author: Charles J. Drane (Jr.) Publisher: ISBN: Category : Antenna radiation patterns Languages : en Pages : 40
Book Description
The optimum design of Dolph-Tchebyscheff broadside arrays of an odd number of elements presents definite computational problems in terms of existing excitation coefficient design procedures, particularly for element spacings of less than a half-wavelength. This paper presents approximate representations for these coefficients in terms of Bessel functions for arrays of, say, more than twenty elements of arbitrary but uniform spacing. To facilitate comparison of the approximations with exact theory, graphs and tables are presented for various main beam--sidelobe ratios, numbers of array elements, and element spacing. (Author).
Author: Thomas G. Evans Publisher: ISBN: Category : Computer-aided design Languages : en Pages : 30
Book Description
The following paper represents work to date on the deformation method for quadratic programming and thus may be regarded as a sequel to Zahl, S. (1964) A Deformation Method for Quadratic Programming, Research Note AFCRL-63-132. It gives an explanation of a modified Iverson programming language and uses this to give a detailed algorithm for the Zahl Deformation Method of Quadratic Programming.
Author: A. F. Armington
Author: A. F. Armington
Author: Alton F. Armington
Author: 
Author: J. T. Buford
Author: G.V. Samsonov
Author: Edward A. Lewis
Author: Takeshi Namioka
Author: Charles J. Drane (Jr.)
Author: K. V. Narasinga Rao
Author: Thomas G. Evans