Studies on the decay of surface charges on dielectrics

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Studies on the decay of surface charges on dielectrics

Citation for published version (APA):

Naidu, M. S. (1979). Studies on the decay of surface charges on dielectrics. (EUT report. E, Fac. of Electrical Engineering; Vol. 79-E-100). Technische Hogeschool Eindhoven.

Document status and date: Published: 01/01/1979

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Studies on the decay of surface charges on dielectrics

by

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EINDHOVEN UNIVERSITY OF TECHNOLOGY Department of Electrical Engineering

Eindhoven The Netherlands

STUDIES ON THE DECAY OF SURFACE CHARGES ON DIELECTRICS by M.S. Naidu TH-Report 79-E-100 ISBN 90-6144-100-5 Eindhoven September 1979

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CONTENTS 1. 2. 3. 4. Abstract Introduction

Theory of the experiment Experimental technique Results and discussion References Figures 1 - 13 Page 1 2 2 3 5 7

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-1-STUDIES ON THE DECAY OF SURFACE CHARGES ON DIELECTRICS

ABSTRACT

Results of the measurements of the decay of charges on the surface of different dielectric materials are presented. A conducting ring around the investigated area was used in tests to ascertain that the conduction over the surface was always much smaller than the conduction through the volume. A power law dependence of current and voltage, I

=

K.Vn describes many of the results; exponents (n) as high as 13 and extending over many decades of current have been observed.

The measurements were carried out in the High Voltage Laboratory of the Eindhoven University of Technology, Eindhoven, The Netherlands, under the supervision of its head, Professor dr.ir. P.C.T. van der Laan and with the technical help of Ing. H. Antonides.

Naidu, M.S.

STUDIES ON THE DECAY OF SURFACE CHARGES.ON DIELECTRICS.

Eindhoven University of Technology, Department of Electrical Engineering, Eindhoven, The Netherlands, September 1979.

TH-Report 79-E-100

Present address of the author: Dr. M.S. Naidu,

Department of High Voltage Engineering, Indian Institute of Science,

Bangalore-560012, India

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2

-1. Introduction.

Electrostatic charges playa very important role in the production, working and storage of dielectric materials. This role played by the electrostatic charges if often unexpected and may cause explosions or other dangerous effects. When used for electrical insulation purpose, the surface charging of these dielectrics often causes flashovers, aid the growth processes of breakdown and reduce the insulation performance of the system. Therefore, it is of great importance to study and understand the phenomena of charge decay over the surface and into the bulk of the material. Also, there has been a recent improvement in the quality of the instrumentation used in measuring surface charges (ref. 1-3) and consequently

detailed experiments to study charge decay over surfaces have become possible.

The electrostatic probe is the instrument most commonly used to measure electrostatic charge because of its negligible interference on the distribution of charges to be measured. with such a probe

(Keithly 2503) electrostatic charge decay was measured for pyrex glass, cellulose triacetate (melinex), polyether, polystyrene, perspex and soft polyethylene. From these measurements, values were derived for the exponent of the power law relation between the

current and the voltage and the resistivity of the dielectric material.

2. Theory of the experiment.

In the experiments conducted, the decay of the charge was mostly caused by conduction through the volume of the material. This was checked by means of a conducting ring on the top surface of the dielectric (around the surface area to be investigated) as shown in fig. 1. To suppress the surface conduction entirely, one should apply a voltage to the ring, which at all times equals the decaying potential on the insulator surface. In practice however, the voltage on the ring did not influence the charge decay noticeably, provided the surface of the insulator was well cleaned (pure alcohol) and the sample was protected against air draughts. To minimise the remaining small surface currents even more, the ring was usually kept at an intermediate, but constant voltage. Under these

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3

-on the voltage as given by the following relati-onship (ref. 4-6)

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Where K is a constant which depends upon distribution of the traps. The measured

the density and energy dV

value

at '

the rate of decay of surface charge (potential) equals

dV

=

dt Le. dV

=

dt where K' l/C (2) A.~ _ K' . € .€ ~/

J-I-

J o r A (3 ) d € • € o r

is a constant for a given sample.

The current density through the bulk of the dielectric j can be evaluated from equation (3).

The electric field E can be found from the voltage on the surface of the dielectric

E = V/d (4)

where the assumption is made that no large space charge distortion of the voltage distribution occurs.

From j and E the exponent of the power law dependence (n) can be found from a graph of the logarithms of j and E.

The resistivity of the bulk of the material can also be evaluated from E and j7 for n ~ 1 this value will vary with value of E.

3. Experimental technique.

The experimental set up used has already been dscribed in earlier papers (ref. 1,3). The dielectric surface, which was flat, was charged during 100 sec. by a spraying discharge from a sharp needle 1 em. above the surface (see figures 1 and lA).

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4

-The surface charge was measured using an electrostatic probe, which functions as a potential divider. This probe (Keithly 2503) is

connected via a coaxial electrometer cable to a Keithly electrometer (type 610C) which drives the

The dielectric samples (size

y-deflection of an x-y recorder. 2

15x12 em ) were fastened to a mobile table, which moves under and past the probe for each measurement as shown in fig. 1A. The probe-dielectric distance was always maintained at 1 em. to obtain maximum spatial resolution, to avoid

flashover and to minimise the influence of the probe on the measurement. A control unit was used to monitor the decay times, the opening of the probe shutter, the start and end of the car motion and the operation of the x-y recorder. The dielectric materials tested were as follows:

Sample

Pyrex glass

Cellulose triacetate (Melinex) polyether Polystyrene perspex PO lythene (soft) Thickness (mm) 1.8 0.1 1.02 1.00 1.02 3.31 € r 8.2 3.0 3.0 2.5 3.7 2.8

In all the samples, the conducting ring (fig. 1) had the same dimensions (an octagonal shape with a side of 4 cm. and a diameter of approximately 10 cm; thickness of the silver paint 6 to 10 mm.). Examples of decay characteristics for pyrex-glass, cellulose triacetate and polyether are shown in figures 2 to 7. In figures 2, 4 and 6 the ring was maintained at 2.5 kV while in figures 3, 5 and 7 the ring was at ground potential. In all cases the charging voltage applied to the pin (kept at a distance of 1 cm. from the dielectric surface) was 5 kV for 100 sec. Decay

characteristics obtained for other materials were also similar and are not shown here. From the decay characteristics V (the voltage on the

dV

dielectric surface) and

at

(rate of decay) were calculated using the voltage on the ring i.e. 2.5 kV as a reference in calibration. From V and

~,

j and E were evaluated using equations (3) and (4) and graphs were drawn. The relationship between j and E for the various materials studied are shown in figures 8, 9, 10, 11, 12 and 13.

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5

-4. Results and discussion.

From figures 8 to 13 it is possible to evaluate the exponent (n) of the power-law dependence of the current through the dielectric on the voltage on the surface. The following table summarises the values of n for different dielectric materials investigated. Also shown are the values of the volume resistivity (p) of the materials at a voltage across the dielectric of 3 kV.

F

at V

= 3 kV

Thickness Material n (nro) (nun) Pyrex glass 2.2 2.193 x 1012 1.80 12 Cellulose triacetate 2.4 2.500 x 10 0.10 (Melinex) Polyether 8.3 7.262 x 1014 1.02 Polystyrene 13.0 3.666 x 1014 1.00 Perspex 6.1 2.280 x 1015 1.02 Polyethene (soft) 7.4 6.969 x 1014 3.31

As can be seen from the above table, the values of n are always greater than 2 for the materials investigated. In dielectric materials the flow of charges are normally controlled by space charges. If the dielectric is an ideal one and is free of traps, the value of n should equal two. Higher values of n have been observed and were interpreted in terms of the influence of traps on conduction processes and of the effect of non-uniform patterns of current flow (ref. 4-6). Higher exponents (n) and extending over many decades of current have been observed in

amosphous and glassy materials (ref. 5). Sixth power laws were found in zirconium oxide and titanium oxide (ref. 5). Exponents varying between 6-8 have been reported in germanium and silicon (ref. 7). However, there appears to be no data available on these values for the dielectrics inve&tigated.

Lampert's (ref. 4) model for the study of single-crystal CdS cannot be applied to the sudy of the behaviour of dielectrics because it has limitation& even in materials such as crystalline insulators and semi-conductor& in which it was expected to apply. It is extremely difficult to obtain relaibale estimates of the density and depth of traps from

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6

-the current-voltage relationship.

There appears to be no satisfactory explanation of this power law and it would be interesting to investigate specific aspects of this

complicated problem. It should be interesting to test the space-charge limited model by studying the current-voltage relationship at

different thicknesses of the sample, which eor a simple space-charge limited regime should follow a definite power-law relationship. Also, the traps may not respond to a short pulse and so transient response characteristics may help to distinguish between the trap-filled limit high power law and other mechanisms.

From figures 8 and 9 (in case of glass and melinex) values of n were evaluated for (a) when the ring potential was 2.5 kV and (b) when the ring was at ground potential, and were found to be nearly the same in both cases. Only values obtained when the ring was maintained at

2.5 kV were shown in the table because only in this case the conduction was mainly through the volume and the surface conduction was absent.

Resistivity values calculated are in good agreement with those obtained by Haenen (ref. 1) for glass and perspex and with the values available in literature for other materials.

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7

-REFERENCES.

1. H.T.M. Haenen, J. of Electrostatics, vol. 1, 173 (1975).

2. T.R. Foord, J. Phys. E. (sci.Instr.), vol. 2, 411 (1969).

3. H.T.M. Haenen, J. of Electrostatics, vol. 2, 203 (1976/1977).

4. M.A. Lampert, A. Many and P. Mark, Phys. Rev., vol. 135, A1444 (1964).

5. A.K. Jenscher, Thin solid films, vol. 1,213 (1967).

6. M.A. Lampert, Rep. on Progress in Physics, vol. 27, 329 (1967).

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Ring

,

Pin connected to High Voltage.

W~J~0h;iW~Q

I I 1 1 I I I

I

1

I

I I I

I

Dielectric

I

r---1...-

j - - -

---1---+

----1

I 1

I

1 I

I

1 I

I

I I 1 1

I

1

1 I ;

1

I

:

I

I I

I

:

I I

I

I I I I I

I

I I I I I I I I I

I

I I I I

I

to High Voltage.

I

I I

:.. ____________________

...c~l~e!:..~~nte~ ~t!h.!"-!.I~!!:~d!;_J

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Charging pin Probe

Dielectric test sample.

~

fig: 101. The test sample stays below the pin for 100 sec. during charging. Afterwards, it moves back and forth under the probe at pre -determined

intervals when the potential corresponding to the charge on the dielectric surface was recorded.

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2.5kV

!

1

5 kV/100 sec

1500

fig:2 Decay characteristics of pyrex glass, thickness 1.8 mm. Distances: probe -glass = IOmm; pin glass = 10mm.

4000 6000

2.5 kV

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5 kV/l00 sec

J

10 fig: 3 Decay characteristics of pyrex glass; thickness 1.8

mm.

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~

S kVlIOO sec

t

_2.SkV

fig: 4 Decay characteristics of cellulose triacetate; thickness 0.1 mm. Distances: probe - dielectric = 10 mm; pin-dielectric

aID

mm.

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15 kV /100 sec

10 fig: 5 Decay charactenstlCs of cellulose triacetate; thickness and distances

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A

~

5 kV 1100 sec

2.5 kV 2.5 kV

1 J

fig: 6 Decay characteristics of polyether; thickness 1.02 mm. Distances: probe- dielectric =10 mm; pin -dielectric

=

10 mm.

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~

5kV 1100 sec

fig:7 Decay characteristics of polyether; thickness 1.02 mm. Distances as shown in fig: 6.

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- - ; - - -

- - - - -

1----

--

--- - - - -I---- --- --- ---

---1

j<Am"'

-

_._-

_------.-~- - - -~--1----

---!

'I

/

II

1 /

--[l

f---:;

8

oV

/

10 A

/

V

1--- - 1---- - - .-.•

J

v

-10

9 II

/

v

/

- -

--

t--- ." -- •...

---

_{I-- --}

-

---E(Vlml 0 ~ -1 10 4 10

fig;8 Current density as a function of electric field for pyrex glass. 1.8 mm thick.

er

=

8.2

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----

.. --~--1---- ---

---II

/

-- -- -- - f--- 1--- - --

-ill

rl

- -2

l

](Am _) __

--/

°

_f

I

-V

;

r-

1---

°1

- --- . __ .. _--. -- ... -_. -- -- ~-.--" .. f--- --- --

-I

01 I

5

;

10

_I

,

I

I I

f

,0

I. I

/

I

/c

-- - , ... _-- _{-- --} - .. '- - --

1----__ 1._

_-

---I

I

/

1---I/°

_I

-10

II

f

6 _II

x

.I

!I

I I

I

I I

I.

-

- --

~- .. _.

r-'I;

- - - -~---- --- --- ... - I 1--- - - --_.--. - - -' . --.•

---Il

'/

I

-7 ECMV/m)

1

10 100 101 102

fig: 9 Current density as a function of electric field for cellulose triacetate, 0.1

mm

thick. Er

~3.o

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-8

10

-9

10 -10 10

1

j(Am-2)

x

0

,

I

:

i

x

,

I

~I

,

I

i

;

1 de

,

!

;

,

/0

I

/0

I

,0

I

)(/0

,

- I

,

X ,

;

/0

II .11

I

,

;

,

I

,

~

E

(Mll/m)

lig:10 Current density as a function of electric field

for polyether, 1.02

mm

thick. Er "3.0

-_ring at ground potental;

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-10

10

-1

10

1 -1

10

2

I

j(Am-2) o I 0 0 0 v 0

,

E(MVlm)

•

fig:ll Current density as a function of electric field for perspex, 1.02 mm thick. Er =3.7

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-9

10 -10 10 -1 10 1

1 j(Am-

2 )

r---.~----I

i

,

I

I I I 0

t---0 0 E(MV/m)

•

fig: 12 Current density as a function of electric field for polystyrene. 1.0

mm

thick. tr

=2.5

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-8 10 -9

f

j(Am-2) ,---f - - - .

-.

-10 -10 1 .

fig: 13 Current density as a polyethylene, 3.31 mm 0 0 0 E(MV/m) 100 function of electric field for

thick. cr =2.8

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EINDHOVEN UNIVERSITY OF TECHNOLOGY THE NETHERLANDS

DEPARTMENT OF ELECTRICAL ENGINEERING

Reports:

1) Dijk, J., M. Jeuken and E.J. Maanders

AN ANTENNA FOR A SATELLITE COMMUNICATION GROUND STATION (PROV ISIONAL ELECTRICAL DESIGN).

TH-Report 68-E-01. 1968. ISBN 90-6144-001-7 2) Veefkind, A .• J.H. Blom and L.H.Th. Rietjens

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A COMPARISON OF SOME PROCESS PARAMETER ESTIMATING SCHEMES. TH-Rcport 68-E-03. 1968. ISBN 90-6144-003-3

4) Eykhoff, P .• P.J.M. Ophey, J. Severs and J.O.M. Oome

AN ELECTROLYTIC TANK FOR INSTRUCTIONAL PURPOSES REPRESENTING THE COMPLEX-FREQUENCY PLANE.

TH-Report 68-E-02. 1968. ISBN 90-6144-004-1 5) Vermij, L. and J.E. Daalder

ENERGY BALANCE OF FUSING SILVER WIRES SURROUNDED BY AIR. TH-Report 68-E-05. 1968. ISBN 90-6 I 44-005-X

6) Houben, J.W.M.A. and P. Mussee

MHO POWER CONVERSION EMPLOYING LIQUID METALS. TH-Report 69-E-06. 1969. ISBN 90-6144-006-8

7) Heuvel, W.M.C. van den and W.F.J. Kersten

VOLTAGE MEASUREMENT IN CURRENT ZERO INVESTIGATIONS. TH-Report 69-E-07. 1909. ISBN 90-6144-007-6

X) Vermij, L.

SELECTED BIBLIOGRAPHY OF FUSES. TH- Report 69-E-08. 1909. ISBN 90-6144-008-4 l)) Westenoorg. J .Z_

SOME IDENTIFICATION SCHEMES FOR NON-LINEAR NOISY PROCESSES. TH-Report 69-E-09. 1909. ISBN 90-6144-009-2

10) Koop. H.E.M., J. Dijk and E.J. Maanders ON CONICAL HORN ANTENNAS.

TH-Report 70-E-10. 1970. ISBN 90-6144-010-6 I I) Veefkind. A.

NON-EQUILIBRIUM PHENOMENA IN A DISC-SHAPED MAGNETOHYDRODYNAMIC GENERATOR.

TH-Report 70-E-I1. 1970. ISBN 90-6144-011-4 12) Jansen, J.K.M., M.E.J. Jeuken and C.W. L::m:,rechtse

THE SCALAR FEED.

TH-Report 70-E-12. 1969. ISBN 90-6144-012-2 13) Teuling. D.J.A.

ELECTRONIC IMAGE MOTION COMPENSATION IN A PORTABLE TELEVISION CAMERA. TH-Report 70-E-I3. 1970. ISBN 90-6144-013-0

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AUTOMATIC METEOR REFLECTIONS RECORDING EQUIPMENT. TH-Report 7Q..E-14. 1970. ISBN 90-6144-014-9

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THE INSTRUMENTAL VARIABLE METHOD AND RELATED IDENTIFICATION SCHEMES. TH-Report 7Q..E-15. 1970. ISBN 90-6144-015-7

16) White. Jr., R.C.

A SURVEY OF RANDOM METHODS FOR PARAMETER OPTIMIZATION. TH-Report 7Q..E-16. 1971. ISBN 90-6144-016-5

17) Ta1mon, J.L.

APPROXIMATED GAUSS-MARKOV ESTIMATORS AND RELATED SCHEMES. TH- Report 71-E-17. 1971. ISBN 9Q..6 I 44-0 17-3

18) Kahlkk, V.

MEASUREMENT OF TIME CONSTANTS ON CASCADE D.C. ARC IN NITROGEN. TH-Report 71-E-18. 1971. ISBN 90-6144-018-1

19) Hosselet, L.M.L.F.

OZONBILDUNG MITTELS ELEKTRISCHER ENTLADUNGEN. TH-Report 71-E-19. 1971. ISBN 9Q..6 I 44"()1 9-X

20) Arts, M.G.J.

ON THE INSTANTANEOUS MEASUREMENT OF BLOODFLOW BY ULTRASONIC MEANS. TH-Report 71-E-20. 1971. ISBN 90-6 I 44"()2Q..3

21) Roer, Th.G. van oe

NON-ISO THERMAL ANALYSIS OF CARRIER WAVES IN A SEMICONDUCTOR. TH-Report 71-E-21. 1971. ISBN 90-6144-021-1

22) Jeuken. P.J .• C. Huber and C.E.Mulders

SENSING INERTIAL ROTATION WITH TUNING FORKS. TIl-Report 71-E-22. 1971. ISBN 9Q..6144-022-X

23) Dijk, J., J. M. Berends and E.J. Maanoers

APERTURE BLOCKAGE IN DUAL REFLECTOR ANTENNA SYSTEMS - A REVIEW. TH-Report 71-E-23. 1971. ISBN 9Q..6 I 44-023-8

24) Kregting, J. ano R.C. White, Jr. ADAPTIVE RANDOM SEARCH.

TH-Report 71-E-24. 1971. ISBN 90-6144-024-6 25) Danlen, A.A.H. and H.A.L. Piceni

THE MULTIPLE DIPOLE MODEL OF THE VENTRICULAR DEPOLARISATION. TH-Report 71-E-25. 1971. ISBN 90-6144-025-4

26) Bremmer, H.

A MATHEMATICAL THEORY CONNECTING SCATTERING AND DIFFRACTION PHENOMENA. INCLUDING BRAGG-TYPE INTERFERENCES.

TH-Report 71-E-26. 1971. ISBN 9Q..6144-026-2 27) Bokhoven, W.M.G. vun

METHODS AND ASPECTS OF ACTIVE RC-FILTERS SYNTHESIS. TH-Report 71-E-27. 1970. ISBN 9Q..6144-027-0

28) Boeschoten, F.

TWO FLUIDS MODEL REEXAMINED FOR ACOLLISIONLESS PLASMA IN THE

STATION~IW .sTATE. .'

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Reports:

29) REPORT ON THE CLOSED CYCLE MHO SPECIALIST MEETING. Working group of tbe joint ENEA/IAEA International MHO Liaison Group.

Eindhoven, TIle Netherlands, September 20-22, 1971. Edited. by L.H.Th. Rietjens. TH-Report 72-E-29. 1972. ISBN 90-6144-029-7

30) Kessel, C.G.M. van and J.W.M.A. Houben

LOSS MECHANISMS IN AN MHO GENERATOR. TH-Report 72-E-30. 1972. ISBN 90-6144-030-0 3 J) Veefkind, A.

CONDUCTION GRIDS TO STABILIZE MHO GENERATOR PLASMAS AGAINST IONIZATION INSTABILITIES.

TH Report 72-1'.-31. 1972. ISBN 90-6144-031-9 32) Daalder, J.E., and C.W.M. Vos

DISTRIBUTION FUNCTIONS OF THE SPOT DIAMETER FOR SINGLE- AND MULTI-CATHODE DISCHARGES IN VACUUM.

TH- Report 73-E-32. 1973. ISBN 90-6144-032-7 33) Daalder, J.E.

JOULE HEATING AND DIAMETER OF THE CATHODE SPOT IN A VACUUM ARC. TH-Report 73-E-33. 1973. ISBN 90-6144-033-5

34) HUUer, C.

BEHAVIOUR OF THE SPINNING GYRO ROTOR. TH-Report 73-E-34. 1973. ISBN 90-6144-034-3 35) Bastian, C. et al.

THE VACUUM ARC AS A FACILITY FOR RELEVANT EXPERIMENTS IN FUSION RESEARCH. Annual Report 1972. EURATOM-T.H.E. Group 'Rotating Plasma'. TH-Report 73-E-35. 1973. ISBN 90-6144-035-1

3M Blol11, J.A.

ANALYSIS OF PHYSIOLOGICAL SYSTEMS BY PARAMETER ESTIMATION TECHNIQUES. TH-Report 73-E-36. 1973. ISBN 90-6 I 44-036-X

37) Cancelled

38) Alldriessen, F.J., W. Boerman and I.F.E.M. Holtz

CALCULATION OF RADIATION LOSSES IN CYLINDER SYMMETRIC HIGH PRESSURE DISCHARGES BY MEANS OF A DIGITAL COMPUTER.

TH-Report 73-E-38. 1973. ISBN 90-6144-038-6

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TH-Report 73-E-39. 1973. ISBN 90-6144-039-4 40) Goes, W.P.

SEPARATION OF SIGNALS DUE TO ARTERIAL AND VENOUS BLOOD FLOW IN THE DOPPLER SYSTEM THAT USES CONTINUOUS ULTRASOUND.

TH-Report 73-E-40. 1973. ISBN 90-6144-040-8 41) Darnen, A.A.H.

A COMPARATIVE ANALYSIS OF SEVERAL MODELS OF THE VENTRICULAR DEPOLARIZATION; INTRODUCTION OF A STRING-MODEL.

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THEORY OF GYRO WITH ROTATING GIMBAL AND FLEXURAL PIVOTS. TH· Report 73-E-42. 1973. ISBN 90-6144-042-4

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ON THE IDENTIFICATION OF CONTINOUS LINEAR PROCESSES. TH·Report 74-E-43. 1974. ISBN 90-6144-043-2

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TH·Report 74-E-44. 1974. ISBN 90-6144-044-0 45) Bastian, C. et al.

EXPERIMENTS WITH A LARGE SIZED HOLLOW CATHODE DISCHARDE FED WITH ARGON. Annual Report 1973. EURATOM·T.H.E. Group 'Rotating Plasma'.

TH·Report 74-E-45. 1974. ISBN 90-6144-045-9 46) Roer, Th.G. van de

ANALYTICAL SMALL·SIGNAL THEORY OF BARITI DIODES. TH·Report 74-E-46. 1974. ISBN 90-6144-046-7

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THE DESIGN OF A MOCK CIRCULATION SYSTEM. TH·Report 74-E-47. 1974. ISBN 90-6144-047-5

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SOME NOTES ON THE INVERSE PROBLEM IN ELECTRO CARDIOGRAPHY. TH·Report 74-E-48. 1974. ISBN 90-6144-048-3

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TlI·Report 74-E-49. 1974. ISBN 90-6144-049-1 50) Puel, A.P.M. van der

A COMPUTER SEARCH FOR GOOD CONVOLUTIONAL CODES. TH·Report 74-E-50. 1974. ISBN 90-6144-050-5

51) Sampie, G.

THE BIT ERROR PROBABILITY AS A FUNCTION PATH REGISTER LENGTH IN THE VITERBI DECODER.

TH·Report 74-E-51. 1974. ISBN 90-6144-051-3 52) Schalkwijk, J.P.M.

CODING FOR A COMPUTER NETWORK. TH·Report 74-E-52. 1974. ISBN 90-6144-052-1 53) Stapper, M.

MEASUREMENT OF THE INTENSITY OF PROGRESSIVE ULTRASONIC WAVES BY MEANS OF RAMAN·NA TH DIFRACTION.

TH·Report 74-E-53. 1974. ISBN 90-6144-053-X 54) Sehalkwijk, J.P.M. and A.J. Vinck

SYNDROME DECODING OF CONVOLUTIONAL CODES. TH·Report 74-E-54. 1974. ISBN 90-6144-054-8

55) Yakimov, A.

FLUCTUATIONS IN IMPATT·D10DE OSCILLATORS WITH LOW Q-FACTORS. TH·Report 74-E-55. 1974. ISBN 90-6144-055-6

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Reports:

56) Plaats, J. van der

ANAL YSIS OF THREE CONDUCTOR COAXIAL SYSTEMS. Computer-aided determination of the frequ~ncy characteristics and the impulse and step resl?onse of a two-port consisting of a system of three coaxial conductors terminating in lumped impedances.

TH-Report 75-E-56. 1975. ISBN 90-6144-056-4 57) Kalken, P.J.H. ami C. Kooy

RAY-OPTICAL ANALYSIS OF A TWO DIMENSIONAL APERTURE RADIATION PROBLEM. Til-Report 75-E-57. 1975. ISBN 90-6144-057-2

58) Schalkwijk, J.P.M., A.J. Vinck and L.J.A.E. Rust

ANALYSIS AND SIMULATION OF A SYNDROME DECODER FOR A CONSTRAINT LENGTH k

=

5, RATE R

=

% BINARY CONVOLUTIONAL CODE.

TH-Report 75-E-58. 1975. ISBN 90-6144-058-0. 59) Boeschoten, F. et al.

EXPERIMENTS WITH A LARGE SIZED HOLLOW CATHODE DISCHARGE FED WITH ARGON,II. Annual Report 1974. EURATOM-T.H.E. Group 'Rotating Plasma'.

TH-Report 75-E-59. 1975. ISBN 90-6144-059-9 60) Maanders, E.J.

SOME ASPECTS OF GROUND STATION ANTENNAS FOR SATELLITE COMMUNICATION. TH-Report 75-E-60. 1975. ISBN 90-6144-060-2

61) Mawira, A. and J. Dijk

DEPOLARIZATION BY RAIN: Some Related Thermal Emission Considerations. TH-Report 75-E-61. 1975. ISBN 90-6144-061-0

62) Safak, M.

CALCULATION OF RADIATION PATTERNS OF REFLECTOR ANTENNAS BY HIGH-FREQUENCY ASYMPTOTIC TECHNIQUES.

TH-Report 76-E-62. 1976. ISBN 90-6144-062-9 (3) Schalkwijk, J.P.M. and A.J. Vinck

SOFT DECISION SYNDROME DECODING. TH-Report 76-E-63. 1976. ISBN 90-6144-063-7 <>4) Damen, A.A.H.

EPICARDIAL POTENTIALS DERIVED FROM SKIN POTENTIAL MEASUREMENTS. Til-Report 76-E-64. 1976. ISBN 90-6144-064-5

65) Bakhuizen, A.J.C. and R. de Boer

ON THE CALCULATION OF PERMEANCES AND FORCES BETWEEN DOUBLY SLOTTED STRUCTURES.

TH-Report 76-E-65. 1976. ISBN 90-6144-065-3 66) Geutjes, A.J.

A NUMERICAL MODEL TO EVALUATE THE BEHAVIOUR OF A REGENERATIVE HEAT EXCHANGER AT HIGH TEMPERATURE.

TH-Report 76-E-66. 1976. ISBN 90-6144-066-1 67) Boeschoten, F. et aI.

EXPERIMENTS WITH A LARGE SIZED HOLLOW CATHODE DISCHARGE, III; concluding work Jan. 1975 to June 1976 of the EURATOM-THE Group 'Rotating Plasma'.

TH-Report 76-E-67. 1976. ISBN 90-6144-067-X 68) CanceUed.

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DEPARTMENT OF ELECfRICAL ENGINEERING

Reports:

69) Merck, W.F.H. and A.F.e. Sens

THOMSON SCATTERING MEASUREMENTS ON A HOLLOW CATHODE DISCHARGE. TH-Report 76-E-69. 1976. ISBN 90-6144-069-6

70) Jongbloed, A.A.

STATISTICAL REGRESSION AND DISPERSION RATIOS IN NONLINEAR SYSTEM IDENTIFICATION.

TH-Report 77-E-70. 1977. ISBN 90-6 I 44-070-X 71) Barrett, J .F.

BIBLIOGRAPHY ON VOLTERRA SERIES HERMITE FUNCTIONAL EXPANSIONS AND RELATED SUBJ ECTS.

TH-Report 77-E-71. 1977. ISBN 90-6144-071-8 72) Boeschoten, F. and R. Komen

ON THE POSSIBILITY TO SEPARATE ISOTOPES BY MEANS OF A ROT A TING PLASMA COLUMN: Isotope separation with a hollow cathode discharge.

TH-Report 77-E-72. 1977. ISBN 90-6144-072-6 73) Schalkwijk, -'.P.M., A.J. Vinck and K.A. Post

SYNDROME DECODING OF BINARY RATE-kin CONVOLUTIONAL CODES. TH-Report 77-E-73. 1977. ISBN 90-6144-073-4

74) Dijk, J., E.J. Maanders and J .M.J. Oostvogels

AN ANTENNA MOUNT FOR TRACKING GEOSTATIONARY SATELLITES. TH-Report 77-E-74. 1977. ISBN 90-6144-074-2

75) Vinck, A.J., J.G. van Wijk and A.J.P. de Paepe

A NOTE ON THE FREE DISTANCE FOR CONVOLUTIONAL CODES. TH-Report 77-E-75. 1977. ISBN 90-6144-075-0

7<» Daalder, J.E.

RADIAL HEAT FLOW IN TWO COAXIAL CYLINDRICAL DISKS. 'I'll-Report 77-E-76. 1977. ISBN 90-6144-076-9

77) Barrett, J.F.

ON SYSTEMS DEFINED BY IMPLICIT ANALYTIC NONLINEAR FUNCTIONAL EQUATIONS.

TH-Report 77-E-77. 1977. ISBN 90-6144-077-7 78) Jansen, J. and J.F. Barret!

ON THE THEORY OF MAXIMUM LIKELIHOOD ESTIMATION OF STRUCTURAL RELATIONS. Part 1: One dimensional case.

TH-Report 78-E-78. 1977. ISBN 90-6144-078-5

79) Borghi, C.A., A.F.C. Sens, A. Veefkind and L.H.Th. Rietjens

EXPERIMENTAL INVESTIGATION ON THE DISCHARGE STRUCTURE IN A NOBLE GAS MHD GENERATOR.

TH-Report 78-E-79. 1978. ISBN 90-6144-079-3 80) Bergmans, T.

EQUALIZATION OF A COAXIAL CABLE FOR DIGITAL TRANSMISSION: Computer-optimized location of poles and zeros of a constant-resistance network to equalize a coaxial cable 1.2/4.4 for high-speed digital transmission (J 40 Mb/s).

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EINDHOVEN UNIVERSITY OF TECHNOLOGY THE NETHERLAND~

Reports:

81 \ Kam. J.1. van der and A.A.H. Damen

OBSERVABILITY OF ELECTRICAL HEART ACTIVITY STUDIES WITH THE SINGULAR VALUE OECOMPOSlTION

TH-Report 78-E-81. 1978. IS13N 90-6144-081-5 82) Jansen. J. and J.F. Barrett

ON THE THEORY OF MAXIMUM LIKELIHOOD ESTIMATION OF STRUCTURAL RELATIONS. Part 2: Multi-dimensional case.

TH-Report 78-E-82. 1978. ISBN 90-6144-082-3 83) Etten. W. van and E. de J ong

OPTIMUM TAPPED DELAY LINES FOR THE EQUALIZATION OF MULTIPLE CHANNEL SYSTEMS.

TH-Report 78-E-83. 1978. ISBN 90-6144-083-1 83) Vinck, A.J.

MAXIMUM LIKELIHOOD SYNDROME DECODING OF LINEAR 13LOCK CODES. TH-Report 78-E-84. 1978. ISBN 90-6 I 44-084-X

85) Spruit, W.P.

A DIGITAL LOW FREQUENCY SPECTRUM ANALYZER, USING A PROGRAMMABLE POCKET CALCULATOR.

TH-Report 78-E-85. 1978. ISBN 90-6144-085-8 86) Beneken, J. E. W. et al

TREND PREDICTION AS A 13ASIS FOR OPTIMAL THERAPY. TH-Report 78-E-86. 1978. ISBN 90-6144-086-6

87) Geus. C.A.M. and J. Dijk

CALCULATION OF APERTURE AND FAR-FIELD DISTRIBUTION FROM MEASUREMENTS IN THE FRESNEL ZONE OF LARGE REFLECTOR ANTENNAS.

TH-Report 78-E-87. 1978. ISBN 90-6144-0874 88) Hajdasinski, A. K.

THE GAUSS-MARKOV APPROXIMATED SCHEME FOR IDENTIFICATION OF MULTIVARIABELE DYNAMICAL SYSTEMS VIA THE REALIZATION THEORY. An Explicit Approach.

TH-Report 78-E-88. 1978. ISBN 90-6144-088-2 89) Niederlinski. A.

THE GLOBAL ERROR APPROACH TO THE CONVERGENDE OF CLOSED-LOOP IDENTIFICATION, SELF-TUNING REGULATORS AND SELF-TUNING PREDICTORS. TH-Report 78-E-89. 1978. ISBN 90-6144-089-0

90) Vinck, A.J. and A.J.P. de Paepe

REDUCING THE NUMBER OF COMPUTATIONS IN STACK DECODING OF CONVOLUTIONAL CODES BY EXPLOITING SYMMETRIES OF THE ENCODER. TH- Report 78-E-90. 1978. ISBN 90-6144-0904

91) Geutjes, A.J. and D.J. Kleyn

A PARAMETRIC STUDY OF 1000 MWe COMBINED CLOSED CYCLE MHD/STEAM ELECTRICAL POWER GENERATING PLANTS.

TH-Report 78-E-91. 1978. ISBN 90-6144-091-2 92) Massee, P.

THE DISPERSION RELATION OF ELECTROTHERMAL WAVES IN A NONEQUILIBRIUM MHDPLASMA.

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EINDHOVEN UNIVERSITY OF TECHNOLOGY' . THE NETHERLANDS

DEPARTMENT OF ELECTRICAL ENGINEERING

Reports:

93} Duin, C.A. van

DIPOLE SCATTERING OF ELECTROMAGNETIC WAVES PROPAGATION THROUGH A RAIN MEDIUM. TH-Report 79-E-93. 1979. ISBN 90-6144-093-9

94) Kuijper, A.H. de and L.K.J. Vandamme

CHARTS OF SPATIAL NOISE DISTRIBUTION IN PLANAR RESISTORS WITH FINITE CONTACTS. TH-Report 79-E-94. 1979. ISBN 90-6144-094-7

95) Hajdasinski, A.K. and A.A.H. Damen

REALIZATION OF THE MARKOV PARAMETER SEQUENCES USING THE SINGULAR VALUE DECOMPOSITION OF THE HANKEL MATRIX. TH-Report 79-E-95. 1979.

ISBN 90-6144-095-5 96) Stefanov, B.

ELECTRON MOMENTUM TRANSFER CROSS-SECTION IN CESIUM AND RELATED CALCULATIONS OF THE LOCAL PARAMETERS OF Cs + Ar MHD PLASMAS. TH-Report 79-E-96. 1979.

ISBN 90-6144-096-3 97) Worm, S.C.J.

RADIATION PATTERNS OF CIRCULAR APERTURES WITH PRESCRIBED SIDELOBE LEVELS. TH-Report 79-E-97. 1979. ISBN 90-6144-097-1

98) Kroezen, P.H.C.

A SERIES REPRESENTATION METHOD FOn THE FAR FIELD OF AN OFFSET REFLECTOR ANTENNA. TH-Report 79-E-98. 1979. ISBN 90:"6144-098-X

~)9) Koonen, A.M.J.

ERROR PROBABILITY IN DIGITAL FIBER OPTIC COMMUNICATION SYSTEMS. TH-Report 79-E-99. 1979. ISBN 90-6144-099-8

100) Naidu, M.S.

STUDIES ON THE DECAY OF SURFACE CHARGES ON DIELECTIUCS. TH-Report 79-E-100. 1979. ISBN 90-6144-100-5