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Showing papers by "Academy of Sciences of the Czech Republic published in 1970"


Journal ArticleDOI
TL;DR: In this article, it was shown that the particle acceleration in flares is confined to the initial phase of the flare development preceding the Hα flare maximum and lasting for less than 10 min.
Abstract: Evidence is given that the particle acceleration in flares is confined to the initial phase of the flare development preceding the Hα flare maximum and lasting for less than 10 min. The impulsive acceleration process is confined to a relatively small limited volume of about 5 × 1027 cm3 in the region of highest magnetic gradient in the flare, and its size represents about 0.05 or less of the total extent of the hot condensation which produces the soft X-ray and gradual microwave bursts. About one in fifty particles in this volume is accelerated to energy exceeding 100 keV, the total particle density being ≈ 1010 cm−3. The accelerated electrons produce the impulsive hard X-ray burst, but synchrotron losses greatly reduce the number of relativistic electrons participating in the bremsstrahlung process. Protons above 20 MeV penetrate to the lowest chromosphere and upper photosphere and temporarily increase the temperature in the bombarded region. As the result a flash of continuous emission appears, which should be most expressive below 1527 A. The associated white-light emission shows the bottom of the region where the impulsive acceleration process occurs.

122 citations


Journal ArticleDOI
30 Jun 1970-Gff
TL;DR: Loess sequences in Czechoslovakia and Austria contain continuous sedimentary record from Pleistocene extending into Matuyama epoch as discussed by the authors, and climate changes are sensitively registered in much more detail th...
Abstract: Loess sequences in Czechoslovakia and Austria contain continuous sedimentary record from Pleistocene extending into Matuyama epoch. Climate changes are sensitively registered in much more detail th...

89 citations


Journal ArticleDOI
01 Aug 1970
TL;DR: In this article, a formulation is given and computed solutions are presented for transient solidification accompanied by natural convection in a vertical slot, where the simplifying assumptions made limit the validity of the solutions to systems where GrPr < 500, i.e., to narrow slots or to low values of the superheat.
Abstract: A formulation is given and computed solutions are presented for transient solidification accompanied by natural convection in a vertical slot. It was found that appreciable fluid velocities may be produced by natural convection, the values of which could be comparable to the terminal rising velocities of typical nonmetallic inclusions. The simplifying assumptions made limit the validity of the solutions to systems where GrPr < 500,i.e., to narrow slots or to low values of the superheat; nonetheless, the results should be indicative of the effects of convection at much higher values of GrPr.

72 citations


Journal ArticleDOI
03 Apr 1970-Science
TL;DR: A series of archeomagnetic measurements have been carried out on archeologic materials from Arizona and Mexico which can be compared with results from Europe and Asia and shows a westward drift of geomagnetic intensity at a rate of about 0.24 degree per year.
Abstract: A series of archeomagnetic measurements have been carried out on archeologic materials from Arizona and Mexico which can be compared with results from Europe and Asia This comparison shows a westward drift of geomagnetic intensity at a rate of about 024 degree per year Furthermore, an apparent coincidence between changes in the earth's magnetic moment and changes in the production rate of radiocarbon is observed

69 citations


Journal ArticleDOI
TL;DR: The reverse osmosis technique is applicable for the separation of binary mixtures of alcohols and/or hydrocarbons, including azeotropic and isomeric mixtures as discussed by the authors.
Abstract: : The reverse osmosis technique is applicable for the separation of binary mixtures of alcohols and/or hydrocarbons, including azeotropic and isomeric mixtures. The porous structures of the cellulose acetate membranes used were affected by the composition of the feed solution in contact with them; hydrocarbon liquids tended to collapse their porous structures on continued contact. Hydrogen bonding and solubility parameter may offer valid criteria of preferential sorption for nonelectrolyte binary feed mixtures containing components whose solubilities are governed primarily by either polar or dispersion forces. (Author)

43 citations


Journal ArticleDOI
TL;DR: In this article, a strain of the entomophagous fungus Beauveria bassiana was cultivated under stationary and submersed conditions, and the presence of chitinase, cellulase, proteases, and lipase was ascertained.

42 citations


Journal ArticleDOI
TL;DR: In this paper, the emission spectra of self-, Mn-, Eu- and Sm-activated AlN luminophores under ultraviolet and cathode ray excitation as well as the excitation spectra for Mn and self-activated phosphors are measured.
Abstract: The emission spectra of self-, Mn-, Eu- and Sm-activated AlN luminophores under ultraviolet and cathode ray excitation as well as the excitation spectra for Mn and self-activated phosphors are measured. Basic information about the kinetics, excitation density dependence and energy transfer mechanism is given. The possibility of the direct excitation mechanism of Eu centres is discussed.

38 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of amplitude, frequency, flow-rates, distance between trays, fractional free area and hole size on longitudinal mixing in reciprocating and pulsed sieve-plate columns has been investigated for single-phase flow.
Abstract: Longitudinal mixing in reciprocating and pulsed sieve-plate columns has been investigated for single-phase flow and is described by a model in which both back-mixing between stages and axial mixing within stages is considered. The model proposed expresses the effect of the amplitude, frequency, flow-rates, distance between trays, their fractional free area and hole size on longitudinal mixing. The relations proposed have been verified by experiments, and the values of the constants in the correlation have been determined. On a etudie, dans le cas d'un ecoulement a phase simple, le melange fait en direction longitudinale dans des colonnes pourvues d'une plaque criblee soumise a un mouvement alternatif et des colonnes pulsees; on le decrit au moyen d'un modele ou il se fait a la fois un retro-melange entre les stades et un melange axial durant les stades. Le modele propose indique l'influence sur le melange en direction horizontales de l'amplitude, de la frequence et des debits ainsi que de la distance entre les plateaux, leur surface libre fractionnee et les dimensions de leurs ouvertures. On a verifie experimentalement les relations proposees et trouve les valeurs des constantes dans la correlation.

35 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that in some solid polymers, and in liquids sorbed on, or dispersed in solid lattices, resolution equal to that of pure liquids is obtained.

34 citations



Journal ArticleDOI
TL;DR: Rat-kidney adenosine-3′,5′-cyclic-phosphate phosphodiesterase possesses a number of properties common to the enzyme from other tissues, such as reaction kinetics, pH optimum and methylxanthine and ATP inhibition.

Journal ArticleDOI
TL;DR: A method has been developed for the determination of adenyl cyclase by means of [8-14C]ATP, which is incubated with the enzyme to produce Ado-3′,5′-P, and can be clearly separated from ATP and other metabolites of the latter, no matter what the mammalian tissue source of enzyme.

Journal ArticleDOI
TL;DR: In this article, the shape of the phase boundary of two fluids in systems with a rotational symmetry, and particularly the level of the liquid in a rotating vessel, is studied, and the solutions of these equations, taking into account the boundary conditions, are discussed.
Abstract: The shape of the phase boundary of two fluids in systems with a rotational symmetry, and particularly the level of the liquid in a rotating vessel, is studied. The knowledge of the shape of the surface of such a liquid is necessary for centrifugal moulding of optical surfaces. The dimensionless surface equations are formulated, and the solutions of these equations, taking into account the boundary conditions, are discussed.

Journal ArticleDOI
TL;DR: In the first part of the lecture some new advances in the chemistry of sesquiterpenic lactones are discussed and the revised structures of some guaianolides and germacranolides are presented as discussed by the authors.
Abstract: In the first part of the lecture some new advances in the chemistry of sesquiterpenic lactones are discussed and the revised structures of some guaianolides and germacranolides are presented.

Journal ArticleDOI
TL;DR: In this paper, the dynamical theory of the phase transition in KDP was modified by taking into account the interaction of the a-polarized transverse acoustic phonon both with the proton tunnelling mode and the transverse optic phonon polarized along the c-axis.
Abstract: The dynamical theory of the phase transition in KDP recently developed by Kobayashi (J. Phys. Soc. Japan24 (1968), 497) is modified by taking into account the interaction of the a-polarized transverse acoustic phonon both with the proton tunnelling mode and the transverse optic phonon polarized along thec-axis. The coupled modes of this three-component system are found in the paraelectric phase within the framework of the RPA approximation. The expressions for the sound velocity in the short-circuited (E = 0) crystal and the static susceptibility at constant stress are derived and well known thermodynamic formulae are obtained if the re-normalized elastic constantc 66 and the piezoelectric constanta 36 are introduced. It is shown that these so-called “true” constants should in principle exhibit anomalies near the proton ordering temperature. Also the role of the depolarizing energy in the phase transition of KDP is discussed. The shift of the phase transition temperature of a small insulated particle of KDP is shown to be only a few degrees. Finally, it is explained why the domain structure of a short-circuited or insulated crystal should be essentially the same.

Journal ArticleDOI
TL;DR: The main result of this paper shows that the dynamic programming method [1] yields an algorithm for the solution of the considered problem, which requires minimum number of comparisons.

DOI
01 Jan 1970
TL;DR: In this paper, the authors examine the connection between family formation choices and value orientations, and empirically investigate to what extent the family trajectories have changed across generations and how these practiced family trajectory correspond to cross-cohort changes in socially established norms about family transitions.
Abstract: Dieser Beitrag liegt nur in englischer Sprache vor. Throughout recent decades, a gradual shift away from an early contracted and simple life course pattern which dominated in the 1950s and 1960s to late protracted and more complex patterns could be observed within European countries. Yet, despite multiple cross-national similarities in the changes of individual life course patterns, there exist considerable differences in the form and frequency of these changes. We argue that one possible way of better understanding these variations is to examine the connection between family formation choices and value orientations. Using data from the European Social Survey 2006 we empirically investigate to what extent the family trajectories have changed across generations and how these practiced family trajectories correspond to cross-cohort changes in socially established norms about family transitions. Our results corroborate the assumption of an increasing restandardisation of family lives: Even though family trajectories have become more turbulent involving more stages and stage changes for the younger generation, “deviations” from traditional family patterns (such as unmarried cohabitation) are turning into majority behaviour, i.e. into a “new standard”. Contrasting these trends with developments in family-related norms reveals that the liberalisation in norms appears to precede such changes in actual demographic behaviour, even though European countries differ in the degree and pace to which such normative and behavioural changes have yet taken place. Normal 0 21 false false false DE X-NONE X-NONE /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Normale Tabelle"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin-top:0cm; mso-para-margin-right:0cm; mso-para-margin-bottom:10.0pt; mso-para-margin-left:0cm; line-height:115%; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"MetaNormalLF-Roman","sans-serif"; mso-ascii-font-family:MetaNormalLF-Roman; mso-ascii-theme-font:minor-latin; mso-hansi-font-family:MetaNormalLF-Roman; mso-hansi-theme-font:minor-latin; mso-fareast-language:EN-US;}


Journal ArticleDOI
TL;DR: In this article, the melting behavior of poly(ethylene oxide) fibrillar crystals was compared and the results discussed in relation to their respective morphologies, and it was shown that fibrilar crystals exhibited superheating which increased with the temperature of crystallization.
Abstract: Poly(ethylene oxide) fibrillar crystals were prepared from ethyl alcohol solutions by stirred crystallization in the temperature range 31°-37°C. Electron microscopy and calorimetric measurements show that the crystals consist of a central thread with extended chains and lamellar overgrowths with folded chains. The melting behavior of crystals prepared at the same temperature with stirring (fibrillar) and without stirring (lamellar) was compared and the results discussed in relation to their respective morphologies. The fibrillar crystals exhibited superheating which increased with the temperature of crystallization. This is related to the amount of material which crystallizes in the extended-chain central threads. The relatively narrow temperature range in which the fibrillar crystals form is related to the greater tendency of the highly flexible poly(ethylene oxide) chains to crystallize in the folded conformation. Molecular fractionation occurs during crystallization, and the plot of molecular ...

Journal ArticleDOI
TL;DR: In this paper, the well-known two varieties of ionization waves (striations) in neon are explained as ion-guided and metastable-guided ionization wave with essentially identical propagation mechanism, and the hydrodynamic equations are used for the formulation of the theory and the electron energy distribution is characterised by the mean energy.
Abstract: The well-known two varieties “p” and “r” of ionization waves (striations) in neon are explained as ion-guided and metastable-guided ionization waves with essentially identical propagation mechanism. To obtain both waves as a solution, in the basic system of equations the time-derivatives in the continuity equations for both the ions as well as the metastables are taken into account. At low discharge currents, the rate of change of the metastables is slower than the rate of change of ion density, and both wave varieties develop separately and can exist simultaneously. The hydrodynamic equations are used for the formulation of the theory and the electron energy distribution is characterised by the mean energy. The Druyvesteyn distribution for electrons (instead of the usually used Maxwellian distribution) is used for calculation of the transport coefficients of the electron gas at the low currents, while the dependence of ionization and excitation rates on the mean electron energy is chosen by trial only and fitted to experimental characteristics of the waves. With non-maxwellian transport coefficients, an instability of the ion-guided wave occurs without any influence of stepwise ionization.

Journal ArticleDOI
03 Oct 1970-Nature
TL;DR: The amino-acid composition of trypsinogen isolated from the pancreas of the spiny Pacific dogfish is studied and a preliminary examination of the primary structure of this enzyme is presented, showing a high degree of homology as compared with bovine tryps inogen.
Abstract: THE homology in primary structure of mammalian pancreatic serine proteases is well established1,2. Progress has now been made in the elucidation of the evolutionary history of this group of proteases. Neurath and his co-workers3 studied the amino-acid composition of trypsinogen isolated from the pancreas of the spiny Pacific dogfish and presented a preliminary examination of the primary structure of this enzyme. From these data a high degree of homology as compared with bovine trypsinogen can be inferred. It is now of interest what will be found beyond the gap that separates vertebrate and invertebrate animals. Invertebrate proteases are difficult to investigate because of the small amounts of material obtainable from these animals. In the crayfish Astacus leptodactylus we found an enzyme resembling mammalian trypsin in many respects4,5. It exhibits a distinct tryptic cleavage specificity when tried on the oxidized B-chain of insulin and is inhibited by all natural and synthetic trypsin inhibitors including TLCK. It is a serine protease and possesses the sequence –Asp–Ser–Gly– around the active centre serine residue6. In addition, extended immunological studies have been carried out on the crayfish trypsins of three species which revealed that they do occur as iso-enzymes varying in number and electrophoretic mobility7.

Journal ArticleDOI
TL;DR: In this article, the elastic field of a cylindrical inclusion with plane or antiplane transformation strain is found under assumptions of linear isotropic homogeneous theory of elasticity, and different integral expressions are obtained from expressions known for the three-dimensional case and interpreted in terms of the theory of dislocations.
Abstract: The elastic field of a cylindrical inclusion with plane or antiplane transformation strain is found under assumptions of linear isotropic homogeneous theory of elasticity. Different integral expressions are obtained from expressions known for the three-dimensional case and interpreted in terms of the theory of dislocations. The surface integrals correspond to a volume distribution of infinitesimal dislocation dipoles inside the inclusion, the line integrals to a surface distribution of dislocations in the boundary between the inclusion and matrix. The case of a shear transformation in a rectangular region is discussed in more detail in connection with twinning.

Journal ArticleDOI
TL;DR: Two analogues ofoxytocin have an oxytocin-like contractile effect on the rat mammary gland strip and, in some experiments, on the isolated rat uterus and the antagonism is surmountable, reversible and probably competitive.

Journal ArticleDOI
TL;DR: In this article, the increase in the complex permittivity during switching was calculated from a two-dimensional model of residual nuclei, assuming that domain walls possess a pyramidal step structure.
Abstract: The increase in the complex permittivity during switching is calculated from a two-dimensional model of residual nuclei, assuming that domain walls possess a pyramidal step structure. The resulting formulae are compared with previous experimental data on BaTiO3 and with corresponding formulae from the same model with smooth walls. It is shown that the real part of the permittivity during switching is very sensitive to the presence of steps on moving domain walls and that there is an indication that in BaTiO3 such step structure actually exists.


Journal ArticleDOI
TL;DR: 1-naphthylisothiocyanate is the most suitable for stepwise degradation of proteins because of the luminescent properties of these derivatives being increased up to the order 10−3 to 10−4 μmoles, which is comparable to the sensitivity of the 1-dimethylamino-5- naphthalene sulphochloride (DANSYL) derivatives.

Journal ArticleDOI
TL;DR: In this article, the results of existing macroscopic theories of FMR in bulk metals are discussed and the applicability is analyzed of the resulting formulas in exact and approximative forms, which are used by experimentalists to determine the physically interesting (resonance) parameters (i.e. the spectroscopical splitting factor and the relaxation constant) from the experimental data.
Abstract: In the present work the results of existing macroscopic theories of FMR in bulk metals are discussed and the applicability is analyzed of the resulting formulas in exact and approximative forms, which are used by experimentalists to determine the physically interesting (resonance) parameters (i.e. the spectroscopical splitting factor and the relaxation constant) from the experimental data. In the case of normal skineffect and parallel field configuration the values of the resonance linewidth, the shift of the resonance field and the line symmetry are computed from both the exact and approximative formulas for a typical metallic ferromagnet.

Journal ArticleDOI
TL;DR: The O-methyl- and O-ethyltyrosine analogues of oxytocin and lysine vasopressin and also [2-p-ethylphenylalanine]-oxytocin had little or no constrictor effect on the isolated artery and inhibited its response to the hormones.

Journal ArticleDOI
28 Mar 1970-Nature
TL;DR: Light scattered off particles in circum-terrestrial space may make an appreciable contribution to the zodiacal glow, but just how significant this contribution might be unfortunately is still unknown.
Abstract: LIGHT scattered off particles in circum-terrestrial space may make an appreciable contribution to the zodiacal glow. Just how significant this contribution might be unfortunately is still unknown. The information we have comes directly from the infrared observations by Petersen1 and McQueen2. These show that an appreciable portion of the dust must be in circum-solar orbits, some of it quite near the Sun. Direct observations on the circum-terrestrial components, however, are still ambiguous, despite extensive particle detection experiments from space probes3. Such experiments have been largely sensitive to particles larger than those thought responsible for the zodiacal glow.