Etude des mouvements de molécules linéaires en phase liquide par analyse du profil des bandes d'absorption infrarouge.: II. Bande v3 du sulfure de carbonyle

1972 ◽  
Vol 50 (2) ◽  
pp. 217-225 ◽  
Author(s):  
A. M. Bize ◽  
J. Soussen-Jacob ◽  
J. Vincent-Geisse ◽  
D. Legay ◽  
J. P. Perchard
Keyword(s):  
Potential Barrier ◽  
Correlation Functions ◽  
Carbonyl Sulfide ◽  
Experimental Results ◽  
The Other ◽  
Band Width ◽  
Saturated Hydrocarbons ◽  
Rotational Effect ◽  
The Mean

The band width and profile of v3 mode of carbonyl sulfide (OCS) dissolved in about 30 solvents have been examined. The study of temperature broadening permits the separation of the vibrational and rotational effects and the determination of the potential barrier to rotation. Correlation functions have been plotted from the experimental results; the mean squared torques acting on carbonyl sulfide in various solvents have been calculated from the second and the fourth moments. The obtained results bear evidence of a dominant rotational effect for solutions in saturated hydrocarbons while, for the other solvents, vibrational broadening proves important.

scholarly journals Estimation of the mean normal measure from flat sections

2008 ◽  
Vol 40 (01) ◽  
pp. 31-48
Author(s):  
Markus Kiderlen
Keyword(s):  
A Priori ◽  
The Other ◽  
Consistent Estimator ◽  
Random Set ◽  
Normal Measure ◽  
Mild Assumption ◽  
The Mean ◽  
Vertical Sections ◽  
Almost All

We discuss the determination of the mean normal measure of a stationary random set Z ⊂ ℝ d by taking measurements at the intersections of Z with k-dimensional planes. We show that mean normal measures of sections with vertical planes determine the mean normal measure of Z if k ≥ 3 or if k = 2 and an additional mild assumption holds. The mean normal measures of finitely many flat sections are not sufficient for this purpose. On the other hand, a discrete mean normal measure can be verified (i.e. an a priori guess can be confirmed or discarded) using mean normal measures of intersections with m suitably chosen planes when m ≥ ⌊d / k⌋ + 1. This even holds for almost all m-tuples of k-dimensional planes are viable for verification. A consistent estimator for the mean normal measure of Z, based on stereological measurements in vertical sections, is also presented.

Components of biological variation in prolyl endopeptidase and dipeptidyl-peptidase IV activity in plasma of healthy subjects

1994 ◽  
Vol 40 (9) ◽  
pp. 1686-1691 ◽  
Author(s):  
M Maes ◽  
S Scharpé ◽  
I De Meester ◽  
P Goossens ◽  
A Wauters ◽  
...  
Keyword(s):  
Seasonal Pattern ◽  
Dipeptidyl Peptidase ◽  
Biological Variation ◽  
Dipeptidyl Peptidase Iv ◽  
Prolyl Endopeptidase ◽  
The Other ◽  
Yearly Variation ◽  
Dpp Iv ◽  
The Mean

Abstract We investigated the components of biological variation in plasma prolyl endopeptidase (PEP; EC 3.4.21.26) and dipeptidyl-peptidase IV (DPP IV; EC 3.4..14.5) activity in healthy individuals. We took monthly blood samples from 26 healthy volunteers for determination of plasma PEP and DPP IV activity during one calendar year. The estimated CVs for PEP activity were: total (CVt) = 25.0%, interindividual (CVg) = 13.9%, and intraindividual (CVi) = 16.8%. There was a statistically significant (P < 0.0001) seasonal pattern in plasma PEP activity, with significantly higher values in the fall than in the other seasons. The peak-trough difference in the yearly variation in PEP activity, expressed as a percentage of the mean, was as high as 56.8%. The estimated CVs for DPP IV activity were: CVt = 17.1%, CVg = 14.5%, and CVi = 8.2%. DPP IV activity was significantly (P < 0.0001) higher in summer than in the other seasons but the amplitude of the yearly variation was small.

Quantitative Determimatioh of Sulfur, Chlorine, Potassium, Calcium, Scandium and Titanium in Aqueous Solutions by Radioisotopic Excited Fluorescent Spectrometer and by Conventional X-Ray Spectrometer

1970 ◽  
Vol 14 ◽  
pp. 102-126 ◽  
Author(s):  
Frank L. Chan ◽  
W. Barclay Jones
Keyword(s):  
Particle Size ◽  
Aqueous Solutions ◽  
Experimental Results ◽  
The Other ◽  
X Rays ◽  
Helium Atmosphere ◽  
X Ray ◽  
Effect Of Particle Size ◽  
The One

AbstractAn x-ray spectrometer with experimental results is herewith described using a radiosotope source Fe55 having a halflife of 2.6 years. As a result of the disintegration, the managanese x-rays are capable of exciting fluorescent x-rays of such elements as sulfur, chlorine, potassium, calcium, scandium and titanium in aqueous solutions. These elements with the Ka wavelengths ranging from 5.3729 Å to 2.7496 Å may be designated as between the very soft x-rays on the one hand and the hard x-rays on the other. The x-ray spectrometer presently described has achieved a resolution of 136 ev, FWHM.Simultaneously, these elements have also been quantitatively determined by conventional x-ray fluorescent spectrometers. Since one of the spectrometers is designed to operate in vacuum as well as in helium or air, determination of sulfur, potassium and calcium were carried out in vacuum. Determination of chlorine was carried out in a helium atmosphere, Calcium, scandium and titanium were determined in air with an air-path spectrometer.In the present study aqueous solutions containing these elements were used. The use of aqueous solutions has the inherent advantages of being homogeneous and free from effect of particle size.

scholarly journals II. Observations of the absolute direction and intensity of terrestrial magnetism at Bombay

1869 ◽  
Vol 17 ◽  
pp. 426-427
Keyword(s):  
Horizontal Component ◽  
The Other ◽  
Secular Change ◽  
Horizontal Force ◽  
Annual Change ◽  
Terrestrial Magnetism ◽  
Exact Determination ◽  
The Mean ◽  
Complete Observation

The observations made by the author were of the three usual elements —the Dip, Declination, and Intensity of the Horizontal Component of the Force. They were taken with instruments supplied to the Colaba Observatory in the year 1867 through the Kew Committee of the British Association, after having been tested at the Kew Observatory. The dip-circle was made by Barrow of London, and is furnished with two needles; the other instrument, the unifilar magnetometer, which serves both for observations of declination and horizontal force, was made by Elliott Brothers of London. The results of the observations for dip only have as yet been received from the author. A complete observation consists of thirty-two readings, each end of the needle being read twice in each different position of the needle and circle; and the mean of the thirty-two is taken as the result of the observation. The observations were 178 in number, commencing on the 29th of April 1867, and extending to the 29th of December 1868. They were generally taken, with the two needles alternately, on particular days of the week. Up to August 17, 1867, the observations commenced with either end (A or B) of the needle dipping, and without remagnetizing the needle; i. e . the magnetization for the latter half of one observation was made to serve for the first half of the next observation with the same needle, the two needles having been kept during the interval with contrary poles adjacent in a zinc box; but after August 17, 1867, the needle was always remagnetized, so as to make the end A dip during the first half of the observation. The effect of this change of practice was to produce a marked increase in the accordance of successive observations. Tables are given containing every complete observation made up to the end of 1868, and showing, as well as the mean dip, the partial results in each position of the circle, and with each end of the needle dipping, and also the mean weekly and mean monthly values. The mean dip obtained for the months April to December 1867 was 19° 2'.00, and for the year 1868 was 19° 3'.87. The period embraced by the observations is too limited to allow of an exact determination of the rate of secular change; nevertheless the observations show distinctly that the dip is increasing. The author takes + l'.3 as the rate of annual change.

scholarly journals Spectrophotometric Determination of Caramel Content in Spirits Aged in Oak Casks

2002 ◽  
Vol 85 (3) ◽  
pp. 744-750 ◽  
Author(s):  
Mauricio Boscolo ◽  
Luiz G Andrade-Sobrinho ◽  
Benedito S Lima-Neto ◽  
Douglas W Franco ◽  
Marcia Miguel Castro Ferreira
Keyword(s):  
Clustering Analysis ◽  
Geographic Origin ◽  
The Other ◽  
Ratio Method ◽  
Calibration Model ◽  
First Derivative ◽  
The Mean ◽  
Components Analysis ◽  
Clear Differentiation

Abstract A new methodology was developed for determination of caramel in spirits aged in oak casks. The method is based on differences between the electronic spectra of oak aqueous alcoholic extracts and caramel solutions in the same solvent. The data were treated by 2 different approaches: the simplest one was based on the plot of caramel concentration versus the ratio of absorbance at 210 and 282 nm; the other was based on a partial least squares (PLS) calibration model using the first derivative of the spectral data. Both methodologies were applied to analysis of 159 aged spirit samples. The mean caramel content of several Brazilian sugar cane spirits (cachaça) and all United States whiskies was smaller than that of Scottish whiskies and other brandies from several countries. Correlation was good between caramel concentrations for the same sample calculated by the 2 methods. The uncertainties following PLS and the absorbance ratio method were 0.01 and 0.03 g/L, respectively, for a sample containing 0.45 g/L caramel. Treatment of UV-VIS spectra by pattern recognition using hierarchical clustering analysis and principal components analysis allowed discrimination of the samples as a function of their caramel content. It was possible to distinguish U.S. whiskies from other whiskies, but a clear differentiation among Brazilian cachaças as a function of their geographic origin was not feasible. Small caramel quantities as low as 0.08 g/L were clearly detected by these methodologies.

De Haas – van Alphen effect and Fermi surface of the intermetallic compound PtSn

1970 ◽  
Vol 48 (10) ◽  
pp. 1151-1160 ◽  
Author(s):  
W. N. Cathey ◽  
P. T. Coleridge ◽  
J.-P. Jan
Keyword(s):  
Intermetallic Compound ◽  
Fermi Surface ◽  
Cross Sections ◽  
Experimental Results ◽  
The Other ◽  
Platinum Atom ◽  
Spin Splitting ◽  
Approximate Determination ◽  
Formula Unit

Extremal cross sections of the Fermi surface of the intermetallic compound PtSn (NiAs structure) have been determined by means of the de Haas – van Alphen effect. The Fermi surface proposed here is similar to that found in isostructural AuSn by Edwards et al. Several of the frequencies have been inverted to yield the profile of the corresponding sheets of the Fermi surface. An approximate determination of the dimensions of the other sheets shows that the observed Fermi surface encloses 4.60 ± 0.27 electrons per formula unit; this suggests that one or several sheets of the Fermi surface containing 0.6 d-band holes per platinum atom have remained undetected. Some cyclotron masses have been measured and to explain all the features of the experimental results, it is necessary to invoke spin splitting with a g factor different from 2, and to postulate magnetic breakdown.

scholarly journals On the flow of viscous fluids through smooth circular pipes

1914 ◽  
Vol 91 (623) ◽  
pp. 46-53 ◽  
Keyword(s):  
Capillary Tube ◽  
Viscous Fluids ◽  
The Other ◽  
Stream Line ◽  
Circular Section ◽  
Circular Pipes ◽  
Line Flow ◽  
The Mean ◽  
The Difference

1.The problem of the flow of a viscous fluid through a tube of circular section is of considerable interest both to physicists and to engineers. Since Stokes showed the connection between the viscosity of the fluid and the empirical formula given by Poiseuille for the rate of slow or stream-line flow of the fluid through a capillary tube, the tube method has been one of the most useful and accurate for the determination of viscosity. On the other hand, the extensive use of pipes for the transmission of gas, compressed air, water and oil, at speeds much above those which obtain in a Poiseuille experiment, rendered it necessary to investigate the laws of "turbulent" flow of viscous fluids through tubes, and there are at the present time several formulae in use by engineers giving the mean rate of flow of such a fluid through a pipe and the difference of pressure between its ends.

scholarly journals II. On the application of the conversion of chlorates and nitrates into chlorides, and of chlorides into nitrates, to the determination of several equivalent numbers

1839 ◽  
Vol 129 ◽  
pp. 13-33 ◽  
Keyword(s):  
Hydrochloric Acid ◽  
Nitrous Acid ◽  
The Other ◽  
Improved Method ◽  
Whole Numbers ◽  
The Mean ◽  
The One

1. The following researches originated from some experiments which were undertaken to discover an improved method for ascertaining the quantity of nitrate of potassa existing in crude saltpetre. After several unsuccessful attempts the action of hydrochloric acid was tried. The fact, that nitrates are decomposed by this acid, has been long known; but the nature of the resulting compound of potassium has not, so far as I am aware, been hitherto determined. I anticipated that the nitrate would be decomposed into chloride of potassium. To decide the question some pure nitrate of potassa was mixed with hydrochloric acid, and the mixture heated; while at common temperatures no perceptible action occurs, but immediately the acid becomes hot, decomposition commences. Chlorine and nitrous acid are evolved with copious effervescence, and the nitrate slowly disappears. The solution was gradually evaporated to dryness, and the dry salt treated with an additional quantity of acid until decomposition was no longer evident. The resulting salt was then carefully examined, and it was found to be pure chloride of potassium. This experiment was repeated several times, and all the results concurred in satisfactorily establishing the fact, that nitrate of potassa may be perfectly converted into chloride of potassium, provided a sufficient quantity of the acid be employed, and the temperature necessary to effect the decomposition be properly regulated. 2. So far the decomposition was admirably adapted for the object mentioned at the commencement. The usual impurities, such as chlorides, sulphates, silica, &c. which any sample of crude saltpetre might contain, would obviously remain unchanged, while the nitrate of potassa alone suffering decomposition, its quantity could easily be ascertained, by comparing the weight of the resulting salt with that obtained from a known quantity of absolutely pure nitrate. Several experiments were therefore performed to determine the exact quantity of chloride of potassium corresponding to a known weight of nitrate. The mean result of four experiments gave the ratio of 100 of nitrate to 73·730 chloride. I was then naturally led to compare this result with the equivalent numbers of these two compounds. In this country there are two series of equivalents in general use, one in which whole numbers are adopted, and the other in which fractional parts are admitted. For example, according to the former, nitrate of potassa will be 102, and to the latter 101·3. So chlo­ride of potassium will be 76 and 74·6. Whence, according to the former, every 100 parts of nitrate should yield 74·51 of chloride: the latter gives the ratio of 100 to 73·613. But these results differ considerably from my experiments. In the one case, we have a difference of ·78, and in the other ·12. Whence therefore could they arise? Either the process must be defective, or the equivalent numbers, so generally considered as correct, must be erroneous.

Determination of the Recombination Processes in Copper Ternary Chalcopyrites by Phototransport Measurements

1996 ◽  
Vol 426 ◽  
Author(s):  
Y. Lubianmker ◽  
G. Bitton ◽  
I. Balberg ◽  
O. Resto ◽  
S. Z. Weisz
Keyword(s):  
Level Structure ◽  
Experimental Results ◽  
The Other ◽  
Recombination Level ◽  
Recombination Processes ◽  
General Recombination ◽  
Level Model ◽  
Ternary Chalcopyrites ◽  
Two Level Model

AbstractWe have measured the phototransport properties of CuGaSe2 films as a function of temperature. The simplest model which is consistent with all the experimental results consists of two recombination levels, one of which is donor-like and the other is acceptor-like. This model is similar to the symmetrical two-level model, which we have recently suggested for CuInS2 films. We thus conclude that this model, with slight variations, represents the general recombination level structure in all copper ternary chalcopyrites.

scholarly journals Bakerian Lecture: Stereochemical types and valency groups

1940 ◽  
Vol 176 (965) ◽  
pp. 153-180 ◽  
Keyword(s):  
Linear Structure ◽  
Trigonal Prism ◽  
Experimental Results ◽  
The Other ◽  
Trigonal Bipyramid ◽  
Distorted Tetrahedron ◽  
Electron Pairs ◽  
Regular Octahedron ◽  
The Mean ◽  
Tellurium Tetrachloride

The arrangements in space of the covalencies of a polyvalent atom , while they are subject to small variations seldom exceeding 5 or 10°, tend to conform to quite a limited number of types. It is desirable to relate this grouping to some familiar property of theatom . The property here used is the size (in G. N. Lewis’s sense) of the valency group of the centralatom , and the number of shared electrons which it contains, together with that of the preceding (unshared) electronic group in the atom . The experimental results show the following relations. I. When the valency group is less than 8 we have with a covalency of 2 a linear structure (as in Cl-Hg-Cl), and with one of 3 a plane with equal angles of 120° (as in BF 3 ). II. With a complete octet the arrangement can be either tetrahedral or planar. When the covalency is less than 4 it is always derived from the tetrahedron, as in the triangular OH 2 and th e pyramidal NH 3 . The fully shared octet is always tetrahedral when the preceding group ( n in the grouping ( n ) 8) is 2, 8, or 18. In the transitional elements where 8 < n < 18, it is tetrahedral if n is not much more than 8, and planar if it is not much less than 18; but the two series overlap. III. When there are 10 valency electrons, at least 2 of them (the “inert pair”) unshared, the structure with a dicovalent atom (as in M[I 3 ]) is linear: that of a 4-eovalent atom is found in the thallous and plumbous salts to be planar, but in tellurium tetrachloride it may be a distorted tetrahedron. IV . The peculiar 4-covalent duodecet in M[ICl 4 ] is planar. V. A covalency of 5 is always found to give a trigonal bipyramid. VI. Covalency 6. Three structures are theoretically possible, a trigonal prism, a trigonal antiprism , and a regular octahedron. Experimentally the octahedron is always found, except in a few giant molecules such as those with a nickel-arsenide lattice. The regular octahedron has been found with practically every possible size of the preceding group, as well as with the “inert pair” of electrons. VII. A covalency of 7 can have two different structures, one derived from the octahedron and the other from the trigonal prism. VIII. Covalency 8. The only com pound exam ined, K 4 [Mo(CN) 8 ], has a dodecahedral arrangement of the 8 CN groups. Nearly (but not quite) all the structures can be even more simply related to the size of the valency group by assuming that the mean positions of the electron pairs in this group are the same whether they are shared or not, the structure being linear for 4 electrons, plane symmetrical for 6, either tetra­hedral or plane for 8, a trigonal bipyramid for 10, and an octahedron for 12.

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