Improving the accuracy of the synthesis of the amplitude-phase distribution in an antenna array with an arbitrary geometry

2021 ◽  
Author(s):  
D.D. Gabrielyan ◽  
Dan.S. Fedorov ◽  
Den.S. Fedorov
Keyword(s):  
Antenna Arrays ◽  
Phase Distribution ◽  
Problem Statement ◽  
Arbitrary Geometry ◽  
Radiating Element ◽  
Path Measurement ◽  
The One ◽  
The Given ◽  
Single Approach

Problem statement. One of the constructing antenna arrays (AA) topic is related to the determination of complex amplitudes at the input of the antenna-feeder path, which, taking into account the distortions introduced by the its, ensure the formation of an amplitude-phase distribution (APD), in which the formed DP differed minimally from the set one. The statement of the problem assumes the known number and coordinates of the location of the emitters, the DP of the radiating element in the composition of the radiating opening, a given radiation pattern. It is required to form an APD in a given opening of the AA, which ensures the formation of a DP that has a minimum deviation from the specified one. To solve the problem, the following algorithm is proposed: determination of the APD at the input of the antenna-feeder path, which ensures the formation of a given DP in the absence of distortions introduced by the antenna-feeder path; measurement for the selected directions of the generated DP with the selected APD in the presence of APD distortions introduced by the antenna-feeder path; formation of a refined APD that ensures the fulfillment of required condition in the presence of distortions introduced by the antenna-feeder path of the AA. Objective. Minimize the root-mean-square deviation of the generated PD from the one specified for the AP with the opening of an arbitrary geometry. Results. The results obtained showed: The formulation of the problem of synthesis of the APD allows us to consider, within the framework of a single approach, AA with different geometries, including AA with a non-planar radiating opening, no restrictions are imposed on the shape of the boundary, and linear (quasi-ring) AA, the emitters of which are located along an arbitrary mane. Using the proposed algorithm for the synthesis of APD, which includes three main stages: the formation of APD for a given DP; measurement of complex values of the generated DP; refinement of the APD by determining the corrections while minimizing the standard deviation (SD) between the specified and formed at the first stage of the DP, allows us to form an APD that provides a minimum SD between the specified and formed DP. The performed studies have shown that when choosing the number of angular directions in each plane, comparable to the number of emitters in this plane, there is a large difference between the given and formed DP. When the number of angular directions for measuring the DP is approximately three times greater than the number of emitters in a given plane, the SD between the specified and formed DP is close to the minimum value and practically does not change with further increase.

Integration of one-dimensional equations of motions

2020 ◽  
pp. 79-90
Author(s):  
Gleb L. Kotkin ◽  
Valeriy G. Serbo
Keyword(s):  
Potential Energy ◽  
Field Change ◽  
One Dimensional ◽  
System A ◽  
Small Correction ◽  
The Law ◽  
The One ◽  
The Given ◽  
Equations Of Motions

If the potential energy is independent of time, the energy of the system remains constant during the motion of a closed system. A system with one degree of freedom allows for the determination of the law of motion in quadrature. In this chapter, the authors consider motion of the particles in the one-dimensional fields. They discuss also how the law and the period of a particle moving in the potential field change due to adding to the given field a small correction.

Integration of one-dimensional equations of motion

2020 ◽  
pp. 3-5
Author(s):  
Gleb L. Kotkin ◽  
Valeriy G. Serbo
Keyword(s):  
Potential Energy ◽  
Equations Of Motion ◽  
Field Change ◽  
One Dimensional ◽  
System A ◽  
Small Correction ◽  
The Law ◽  
The One ◽  
The Given

If the potential energy is independent of time, the energy of the system remains constant during the motion of a closed system. A system with one degree of freedom allows for the determination of the law of motion in quadrature. In this chapter, the authors consider motion of the particles in the one-dimensional fields. They discuss also how the law and the period of a particle moving in the potential field change due to adding to the given field a small correction.

scholarly journals XVII. On the double tangents of a curve of the fourth order

1861 ◽  
Vol 151 ◽  
pp. 357-362 ◽  
Keyword(s):  
Fourth Order ◽  
Plane Curve ◽  
Original Form ◽  
Quartic Curve ◽  
Cubic Curve ◽  
Seventh Order ◽  
The One ◽  
The Given ◽  
In Virtue Of

The present memoir is intended to be supplementary to that "On the Double Tangents of a Plane Curve.” I take the opportunity of correcting an error which I have there allen into, and which is rather a misleading one, viz., the emanants U 1 , U 2 ,.. were numerically determined in such manner as to became equal to U on putting ( x 1 , y 1 , z 1 ) equal to ( x, y, z ); the numerical determination should have been (and in the latter part of the memoir is assumed to be) such as to render H 1 , H 2 , &c. equal to H, on making the substitution in question; that is, in the place of the formulæ U 1 = 1/ n ( x 1 ∂ x + y 1 ∂ y + z 1 ∂ z ) 2 U, U 2 = 1/ n ( n -1)( x 1 ∂ x + y 1 ∂ y + z 1 ∂ z ) 2 U, &c., here ought to have been U 1 = 1/( n - 2)( x 1 ∂ x + y 1 ∂ y + z 1 ∂ z )U, U 2 = 1/( n - 2)( n - 3) ( x 1 ∂ x + y 1 ∂ y + z 1 ∂ z ) 2 U, &c. The points of contact of the double tangents of the curve of the fourth order or quartic U = 0, are given as the intersections of the curve with a curve of the fourteenth order II = 0; the last-mentioned curve is not absolutely determinate, since instead of II = 0, we may, it Is clear, write II + MU = 0, where M is an arbitrary function of the seventh order. I have in the memoir spoken of Hesse’s original form (say II 1 = 0) of the curve of the fourteenth order obtained by him in 1850, and of his transformed form (say II 2 = 0) obtained in 1856. The method in the memoir itself (Mr. Salmon’s method) gives, in the case in question of a quartic curve, a third form, say II 3 = 0. It appears by his paper “On the Determination of the Points of Contact of Double Tangents to an Algebraic Curve,” that Mr. Salmon has verified by algebraic transformations the equivalence of the last-mentioned form with those of Hesse; but the process is not given. The object of the present memoir is to demonstrate the equivalence in question, viz. that of the equation II 3 = 0 with the one or other of the equations II 1 = 0, II 2 = 0, in virtue of the equation U = 0. The transformation depends, 1st, on a theorem used by Hesse for the deduction of his second form II 2 = 0 from the original form II 1 = 0, which theorem is given in his paper “Transformation der Gleichung der Curven 14ten Grades welche eine gegebene Curve 4ten Grades in den Berührungspuncten ihrer Doppeltangenten schneiden,” Crelle , t. lii. pp. 97-103 (1856), containing the transformation in question; I prove this theorem in a different and (as it appears to me) more simple maimer; 2nd, on a theorem relating to a cubic curve proved incidentally in my memoir“ On the Conic of Five-pointic Contactat any point of a Plane Curve”, the cubic curve being in the present case any first emanant of the given quartic curve: the demonstration occupies only a single paragraph, and it is here reproduced; and I reproduce also Hesse’s demonstration of the equivalence of the two forms II 1 = 0 and II 2 = 0.

Using Spline Functions for the Shape Description of the Surface of Shell Structures

2014 ◽  
Vol 13 (1) ◽  
Author(s):  
Grzegorz Lenda
Keyword(s):  
Point Of View ◽  
Shell Structures ◽  
Shape Description ◽  
Basic Parameters ◽  
Point Set ◽  
The One ◽  
Half Axis ◽  
The Given ◽  
The Ideal

AbstractThe assessment of the cover shape of shell structures makes an important issue both from the point of view of safety, as well as functionality of the construction. The most numerous group among this type of constructions are objects having the shape of a quadric (cooling towers, tanks with gas and liquids, radio-telescope dishes etc.). The material from observation of these objects (point sets), collected during periodic measurements is usually converted into a continuous form in the process of approximation, with the use of the quadric surface. The created models, are then applied in the assessment of the deformation of surface in the given period of time. Such a procedure has, however, some significant limitations. The approximation with the use of quadrics, allows the determination of basic dimensions and location of the construction, however it results in ideal objects, not providing any information on local surface deformations. They can only be defined by comparison of the model with the point set of observations. If the periodic measurements are carried out in independent, separate points, then it will be impossible to define the existing deformations directly. The second problem results from the one-equation character of the ideal approximation model. Real deformations of the object change its basic parameters, inter alia the lengths of half-axis of main quadrics. The third problem appears when the construction is not a quadric; no information on the equation describing its shape is available either. Accepting wrong kind of approximation function, causes the creation of a model of large deviations from the observed points.All the mentioned above inconveniences can be avoided by applying splines to the shape description of the surface of shell structures. The use of the function of this type, however, comes across other types of limitations. This study deals with the above subject, presenting several methods allowing the increase of accuracy and decrease of the time of the modelling with the splines.

scholarly journals The optimum temperature of salicin hydrolysis by enzyme action is independent of the concentrations of substrate and enzyme

1914 ◽  
Vol 87 (594) ◽  
pp. 245-254 ◽  
Keyword(s):  
Enzyme Concentration ◽  
The Other ◽  
Optimum Temperature ◽  
Constant Concentration ◽  
M 10 ◽  
The One ◽  
The Given ◽  
Hydrolysis Of ◽  
Preliminary Determination

The object of the present investigation is to ascertain the influence, if any, on the optimum temperature—temperature of greatest activity—of an enzyme, of the concentration, on the one hand, of the substrate, and, on the other, of the enzyme. The investigation, involving two variables, presents three cases for consideration, according as the concentration of the substrate and the concentration of the enzyme are varied separately or together. An account is given of the results obtained with the enzyme or enzymic function, present in sweet-almond emulsin, which hydrolyses the glucoside salicin with the production of equimolecular quantities of glucose and saligenin. A commercial specimen of Merck’s emulsin was used, while the purity of the salicin employed was ascertained by determining its melting point (200-5°) and its optical activity ([ α ] 21 D = -62·7°). The successive stages in the inquiry may be briefly summarised as follows: (1) a preliminary determination of the activity of the specimen under certain chosen conditions as regards the concentration of the substrate, the temperature, and the duration of the experiment; (2) a preliminary determination of the optimum temperature with the quantity of enzyme found capable of producing 50 per cent, hydrolysis of the substrate under the above conditions; (3) a determination of the activity curves of the enzyme at the temperature thus found, in an action of the same duration for five concentrations of the substrate M/5, M/10, M/15, M/30, and M/50; (4) a determination of the optimum temperature of the enzyme for each of the five concentrations of the substrate in presence of a constant enzyme concentration ; (5) a determination of the optimum temperature of the enzyme for each of the five concentrations of the substrate with quantities of enzyme indicated by the activity curves as capable of producing 70 per cent, hydrolysis of the substrate in the given time: (6) a determination of the optimum temperature of the enzyme for a constant concentration of the substrate in presence of different enzyme concentrations.

Two-Stage Procedure for the Quantitative Determination of Autoprothrombin III Concentration and Some Applications

1967 ◽  
Vol 18 (01/02) ◽  
pp. 198-210 ◽  
Author(s):  
Ronald S Reno ◽  
Walter H Seegers
Keyword(s):  
Prothrombin Time ◽  
Factor Vii ◽  
Two Stage ◽  
Pronounced Increase ◽  
One Stage ◽  
Assay Procedure ◽  
Bovine Plasma ◽  
The One ◽  
Autoprothrombin C

SummaryA two-stage assay procedure was developed for the determination of the autoprothrombin C titre which can be developed from prothrombin or autoprothrombin III containing solutions. The proenzyme is activated by Russell’s viper venom and the autoprothrombin C activity that appears is measured by its ability to shorten the partial thromboplastin time of bovine plasma.Using the assay, the autoprothrombin C titre was determined in the plasma of several species, as well as the percentage of it remaining in the serum from blood clotted in glass test tubes. Much autoprothrombin III remains in human serum. With sufficient thromboplastin it was completely utilized. Plasma from selected patients with coagulation disorders was assayed and only Stuart plasma was abnormal. In so-called factor VII, IX, and P.T.A. deficiency the autoprothrombin C titre and thrombin titre that could be developed was normal. In one case (prethrombin irregularity) practically no thrombin titre developed but the amount of autoprothrombin C which generated was in the normal range.Dogs were treated with Dicumarol and the autoprothrombin C titre that could be developed from their plasmas decreased until only traces could be detected. This coincided with a lowering of the thrombin titre that could be developed and a prolongation of the one-stage prothrombin time. While the Dicumarol was acting, the dogs were given an infusion of purified bovine prothrombin and the levels of autoprothrombin C, thrombin and one-stage prothrombin time were followed for several hours. The tests became normal immediately after the infusion and then went back to preinfusion levels over a period of 24 hrs.In other dogs the effect of Dicumarol was reversed by giving vitamin K1 intravenously. The effect of the vitamin was noticed as early as 20 min after administration.In response to vitamin K the most pronounced increase was with that portion of the prothrombin molecule which yields thrombin. The proportion of that protein with respect to the precursor of autoprothrombin C increased during the first hour and then started to go down and after 3 hrs was equal to the proportion normally found in plasma.

The Role and Place of Budget Procedure in the System

2003 ◽  
pp. 42-49 ◽  
Author(s):  
E. Bushmin
Keyword(s):  
Budget Process ◽  
Public Expenditures ◽  
Principal Role ◽  
Process Trends ◽  
The Given ◽  
Rules Of The Game

The article is devoted to the analysis of improving budget process trends. The author offers the concept of "financial technologism". Its usage should promote an essential improvement of the budget process. The given concept is based on the fact that the regulation of budget procedure is the process of determination of "rules of the game", and the order of interaction of different institutions within the framework of the budget process, and the trends and volumes of expenses are the strategy of institutions. The procedure within the budget process plays a principal role as compared with the trends and volumes of public expenditures.

SIMPLIFIED DEXAMETHASONE SUPPRESSION TEST

1969 ◽  
Vol 61 (2) ◽  
pp. 219-231 ◽  
Author(s):  
V. H. Asfeldt
Keyword(s):  
Cushing’S Syndrome ◽  
Normal Subjects ◽  
Cushing's Syndrome ◽  
Dexamethasone Suppression Test ◽  
Clinical Value ◽  
Suppression Test ◽  
The One ◽  
Steroid Excretion ◽  
Dexamethasone Suppression

ABSTRACT This is an investigation of the practical clinical value of the one mg dexamethasone suppression test of Nugent et al. (1963). The results, evaluated from the decrease in fluorimetrically determined plasma corticosteroids in normal subjects, as well as in cases of exogenous obesity, hirsutism and in Cushing's syndrome, confirm the findings reported in previous studies. Plasma corticosteroid reduction after one mg of dexamethasone in cases of stable diabetes was not significantly different from that observed in control subjects, but in one third of the insulin-treated diabetics only a partial response was observed, indicating a slight hypercorticism in these patients. An insufficient decrease in plasma corticosteroids was observed in certain other conditions (anorexia nervosa, pituitary adenoma, patients receiving contraceptive or anticonvulsive treatment) with no hypercorticism. The physiological significance of these findings is discussed. It is concluded that the test, together with a determination of the basal urinary 17-ketogenic steroid excretion, is suitable as the first diagnostic test in patients in whom Cushing's syndrome is suspected. In cases of insufficient suppression of plasma corticosteroids, further studies, including the suppression test of Liddle (1960), must be carried out.

THE EU SUGAR MARKET PROFILE AND ITS MAIN DRIVERS

2015 ◽  
Author(s):  
Lubos SMUTKA ◽  
Irena BENEŠOVÁ ◽  
Patrik ROVNÝ ◽  
Renata MATYSIK-PEJAS
Keyword(s):  
Market Failure ◽  
Current System ◽  
Quota System ◽  
Considerable Debate ◽  
Sugar Market ◽  
The Common ◽  
The One ◽  
Production Capacities ◽  
The Given ◽  
The Eu

Sugar is one of the most important elements in human nutrition. The Common Market Organisation for sugar has been a subject of considerable debate since its establishment in 1968. The European agricultural market has been criticized for its heavy regulations and subsidization. The sugar market is one of the most regulated ones; however, this will change radically in 2017 when the current system of production quotas will end. The current EU sugar market changed is structure during the last several decades. The significant number of companies left the market and EU internal sugar market became more concentrated. The aim of this paper is presentation characteristics of sugar market with respect to the supposed market failure – reduction in competition. The analysis also identifies the main drivers and determinants of the EU especially quota sugar market. In relation to paper’s aim the following results are important. The present conditions of the European sugar market have led to market failure when nearly 75 % (10 million tonnes) of the quota is controlled by five multinational companies only. These multinational alliances (especially German and French one) are also taking control over the production capacities of their subsidiaries. In most countries, this causes serious problems as the given quota is controlled by one or two producers only. This is a significant indicator of market imperfection. The quota system cannot overcome the problem of production quotas on the one hand and the demand on the other; furthermore, it also leads to economic inefficiency. The current EU sugar market is under the control of only Sudzucker, Nordzucker, Pfeifer and Langen, Tereos and ABF.

Quasi-Periodic Control Technique for Minimizing Fuel Consumption During Record Vehicle Competition

2013 ◽  
Vol 60 (2) ◽  
pp. 185-197 ◽  
Author(s):  
Paweł Sulikowski ◽  
Ryszard Maronski
Keyword(s):  
Fuel Consumption ◽  
Optimal Control Theory ◽  
Slope Angle ◽  
Control Technique ◽  
Decision Variables ◽  
Aeronautical Engineering ◽  
The One ◽  
Optimal Driving ◽  
The Given ◽  
Engine Power

The problem of the optimal driving technique during the fuel economy competition is reconsidered. The vehicle is regarded as a particle moving on a trace with a variable slope angle. The fuel consumption is minimized as the vehicle covers the given distance in a given time. It is assumed that the run consists of two recurrent phases: acceleration with a full available engine power and coasting down with the engine turned off. The most fuel-efficient technique for shifting gears during acceleration is found. The decision variables are: the vehicle velocities at which the gears should be shifted, on the one hand, and the vehicle velocities when the engine should be turned on and off, on the other hand. For the data of students’ vehicle representing the Faculty of Power and Aeronautical Engineering it has been found that such driving strategy is more effective in comparison with a constant speed strategy with the engine partly throttled, as well as a strategy resulting from optimal control theory when the engine is still active.

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