scholarly journals A note on some further determinations of the dielectric constants of organic bodies and electrolytes at very low temperatures

1898 ◽  
Vol 62 (379-387) ◽  
pp. 250-266 ◽  
Keyword(s):  
Dielectric Constant ◽  
Low Temperatures ◽  
Tuning Fork ◽  
Dielectric Constants ◽  
The Past ◽  
Method Of Measurement ◽  
The Given ◽  
Past Summer

In several previous communications we have described the investigations made by us on the dielectric constants of various frozen organic bodies and electrolytes at very low temperatures. In these researches we employed a method for the measurement of the dielectric constant which consisted in charging and discharging a condenser, having the given body as dielectric, through a galvanometer 120 times in a second by means of a tuning-fork interrupter. During the past summer we have repeated some of these determinations and used a different method of measurement and a rather higher frequency. In the experiments here described we have adopted Nernst’s method for the measurement of dielectric constants, using for this purpose the apparatus as arranged by Dr. Nernst which belongs to the Davy-Faraday Laboratory.

scholarly journals On the measurement of the dielectric constants of liquids, with a determination of the dielectric constant of benzene

1929 ◽  
Vol 123 (792) ◽  
pp. 664-685 ◽  
Keyword(s):  
Dielectric Constant ◽  
Physical Properties ◽  
Dielectric Constants ◽  
Experimental Conditions ◽  
The Past ◽  
A Value ◽  
The Subject ◽  
Important Indication

It has long been recognised that the dielectric constant of a substance gives an important indication of its constitution, and the classical papers of Nernst and Drude giving methods for the determination of dielectric constants, have been followed by a long series of papers giving the dielectric constants of several hundreds of pure liquids and solutions. Since the publication of Debye’s dipole theory in 1912, the literature of the subject has become even more voluminous than before. In surveying the mass of data one is struck by the very large discrepancies which exist in the values obtained by different observers for any one substance, and it is very difficult to decide whether they are due to the difficulty of pre­paring and purifying the substance, differences in experimental conditions such as frequency of the applied E. M. F., or errors in the methods of measure­ment. In order to make it possible to compare the results of different observers, and to provide a fundamental basis for new measurements, it is important that the value of at least one standard liquid should be known with unquestion­able accuracy. The object of the present investigation was to provide such a value. Benzene was chosen as the standard liquid since it has been very widely used in the past, and it is used as a standard in the measurement of other physical properties.

scholarly journals On the dielectric constants of certain frozen electrolytes at and above the temperature of liquid air

1897 ◽  
Vol 61 (369-377) ◽  
pp. 299-316 ◽  
Keyword(s):  
Dielectric Constant ◽  
Low Temperatures ◽  
Dielectric Constants ◽  
Preliminary Note

In a preliminary note on the "Dielectric Constant of Ice and Alcohol at very Low Temperatures" we have described the method employed by us in determining the dielectric constants of ice and frozen ethylic alcohol at the temperature of liquid air. One difficulty which presented itself in our initial experiments was that of the construction of a suitable electrical condenser for use with frozen liquids as dielectrics.

Note on the dielectric constant of ice and alcohol at very Low temperatures

1897 ◽  
Vol 61 (369-377) ◽  
pp. 1-18 ◽  
Keyword(s):  
Dielectric Constant ◽  
Low Temperatures ◽  
Dielectric Constants ◽  
Capacity Of A Condenser

Of late years many careful determinations have been made of the dielectric constants of water and ice by different observers. These evaluations may be divided into two classes. Firstly, those which are, strictly speaking, determinations of the specific inductive capacity of the material, and have been made by measuring the change in the capacity of a condenser when water or ice is substituted for air as the dielectric.

Acquiring penmanship and writing skills from the first to fifth grade of primary school: Joined-up writing vs. Comenia Script

2018 ◽  
Vol 6 (2) ◽  
pp. 1-13
Author(s):  
Olga Kučerová ◽  
Anna Kucharská
Keyword(s):  
Primary School ◽  
Error Rate ◽  
Writing Skills ◽  
Fifth Grade ◽  
Point Scale ◽  
The Past ◽  
School Year ◽  
And Gender ◽  
Developmental Dynamics ◽  
The Given

Abstract The project presented here deals with a typical human means of communication – writing. The aim of the project is to map the developmental dynamics of handwriting from the first to the fifth grade of primary school. The question remains topical because of the fact that several systems of writing have been used in the past few years. Our project focuses on comparing the systems of joined-up handwriting (the standard Latin alphabet) and the most widespread form of printed handwriting: Comenia Script. The research can be marked as sectional; pupils took a writing exam at the beginning and at the end of the 2015/2016 school year. The total number of respondents was 624 pupils, evenly distributed according to the school year, system of writing and gender. To evaluate handwriting, the evaluation scale of Veverková and Kucharská (2012) was adjusted to include a description of phenomena related to graphomotor and grammatical aspects of writing, including the overall error rate and work with errors. Each area that was observed included a series of indicators through which it was possible to create a comprehensive image of the form handwriting took in the given period. Each indicator was independently classified on a three-point scale. Thanks to that, a comprehensive image of the form of writing of a contemporary pupil emerged.

scholarly journals Comment on “investigation of dielectric constants of water in a nano-confined pore” by H. Zhu, F. Yang, Y. Zhu, A. Li, W. He, J. Huang and G. Li, RSC Adv., 2020, 10, 8628

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 5179-5181
Author(s):  
Sayantan Mondal ◽  
Biman Bagchi
Keyword(s):  
Dielectric Constant ◽  
Dielectric Constants ◽  
Static Dielectric Constant ◽  
Inherent Anisotropy ◽  
Nanoconfined Water

Neglects of inherent anisotropy and distinct dielectric boundaries may lead to completely erroneous results. We demonstrate that such mistakes can give rise to gross underestimation of the static dielectric constant of cylindrically nanoconfined water.

DIELECTRIC CONSTANT AND SEEBECK COEFFICIENT FOR SEMICONDUCTORS: THERMODYNAMIC AND DFT STUDIES

2013 ◽  
Vol 12 (06) ◽  
pp. 1350057 ◽  
Author(s):  
HSIU-YA TASI ◽  
CHAOYUAN ZHU
Keyword(s):  
Boundary Condition ◽  
Dielectric Constant ◽  
Seebeck Coefficient ◽  
Gas Phase ◽  
Present Method ◽  
Dielectric Constants ◽  
Semiconductor Materials ◽  
Electronic Polarizability ◽  
Seebeck Coefficients ◽  
Good Agreement

Dielectric constants and Seebeck coefficients for semiconductor materials are studied by thermodynamic method plus ab initio quantum density functional theory (DFT). A single molecule which is formed in semiconductor material is treated in gas phase with molecular boundary condition and then electronic polarizability is directly calculated through Mulliken and atomic polar tensor (APT) density charges in the presence of the external electric field. This electronic polarizability can be converted to dielectric constant for solid material through the Clausius–Mossotti formula. Seebeck coefficient is first simulated in gas phase by thermodynamic method and then its value divided by its dielectric constant is regarded as Seebeck coefficient for solid materials. Furthermore, unit cell of semiconductor material is calculated with periodic boundary condition and its solid structure properties such as lattice constant and band gap are obtained. In this way, proper DFT function and basis set are selected to simulate electronic polarizability directly and Seebeck coefficient through chemical potential. Three semiconductor materials Mg 2 Si , β- FeSi 2 and SiGe are extensively tested by DFT method with B3LYP, BLYP and M05 functionals, and dielectric constants simulated by the present method are in good agreement with experimental values. Seebeck coefficients simulated by the present method are in reasonable good agreement with experiments and temperature dependence of Seebeck coefficients basically follows experimental results as well. The present method works much better than the conventional energy band structure theory for Seebeck coefficients of three semiconductors mentioned above. Simulation with periodic boundary condition can be generalized directly to treat with doped semiconductor in near future.

scholarly journals Optimising the AR Engraved Structure on Light-Guide Facets for a Wide Range of Wavelengths

Optics ◽  
2020 ◽  
Vol 2 (1) ◽  
pp. 25-42
Author(s):  
Ioseph Gurwich ◽  
Yakov Greenberg ◽  
Kobi Harush ◽  
Yarden Tzabari
Keyword(s):  
Theoretical Analysis ◽  
Light Guide ◽  
Spectral Band ◽  
Angular Range ◽  
The Past ◽  
Input And Output ◽  
Wide Range ◽  
The Given ◽  
Theoretical Results ◽  
Shape And Size

The present study is aimed at designing anti-reflective (AR) engraving on the input–output surfaces of a rectangular light-guide. We estimate AR efficiency, by the transmittance level in the angular range, determined by the light-guide. Using nano-engraving, we achieve a uniform high transmission over a wide range of wavelengths. In the past, we used smoothed conical pins or indentations on the faces of light-guide crystal as the engraved structure. Here, we widen the class of pins under consideration, following the physical model developed in the previous paper. We analyze the smoothed pyramidal pins with different base shapes. The possible effect of randomization of the pins parameters is also examined. The results obtained demonstrate optimized engraved structure with parameters depending on the required spectral range and facet format. The predicted level of transmittance is close to 99%, and its flatness (estimated by the standard deviation) in the required wavelengths range is 0.2%. The theoretical analysis and numerical calculations indicate that the obtained results demonstrate the best transmission (reflection) we can expect for a facet with the given shape and size for the required spectral band. The approach is equally useful for any other form and of the facet. We also discuss a simple way of comparing experimental and theoretical results for a light-guide with the designed input and output features. In this study, as well as in our previous work, we restrict ourselves to rectangular facets. We also consider the limitations on maximal transmission produced by the size and shape of the light-guide facets. The theoretical analysis is performed for an infinite structure and serves as an upper bound on the transmittance for smaller-size apertures.

scholarly journals VIII. Account of experiments on torsion and flexure for the determination of rigidities

1867 ◽  
Vol 157 ◽  
pp. 139-153 ◽  
Keyword(s):  
The Past ◽  
Past Summer

In my Paper read February 22nd, 1866, the intention was expressed of continuing my experiments on rigidity with a modified form of apparatus. This intention was carried out during the past summer, and I have now to report the results. In the former experiments, the rod operated on was supported at both ends, and was bent or twisted by hanging a pair of equal weights so as to act symmetrically on both ends; and the amounts of flexure and torsion were measured by the movements of two images formed by reflection upon a screen.

Development of Advanced CNC Interpolation Algorithm With Consideration of Command and Dynamic Errors

2015 ◽  
Author(s):  
Meng-Shiun Tsai ◽  
Ying-Che Huang
Keyword(s):  
The Other ◽  
Contour Error ◽  
Interpolation Algorithm ◽  
Interpolation Scheme ◽  
Error Equation ◽  
The Past ◽  
Cnc Interpolation ◽  
Dynamic Errors ◽  
Simulation Results ◽  
The Given

In this paper, an integrated acceleration/deceleration with dynamics interpolation scheme is proposed to confine the maximum contour error at the junction of linear junction. The dynamic contour error equation is derived analytically and then it is utilized for the interpolation design. Based on the derived formulations which could predict the command and dynamic errors, the advanced interpolation design could adjust the connecting velocity of the two blocks to confine the overall contour errors under the given tolerance. Simulation results validate the proposed algorithm can achieve higher accurate trajectory as compared to the other interpolation algorithm proposed in the past.

scholarly journals On an Internal Parasite (Hym.—Chalcidoidea) of a Thrips from Trinidad

1923 ◽  
Vol 13 (4) ◽  
pp. 453-455 ◽  
Author(s):  
James Waterston
Keyword(s):  
Prepupal Stage ◽  
The Past ◽  
Internal Parasite ◽  
Past Summer

During the past summer Mr. F. W. Urich, Government Entomologist, Trinidad, B.W.I., succeeded in rearing a number of small Chalcids from larvae of a thrips in the prepupal stage. The following description is based on part of this material.

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