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1.
A. J. Ritger H. Meissner R. Rangel L. Kramer 《Journal of Low Temperature Physics》1988,73(3-4):221-227
Comparison of the measured microwave response in the presence of a dc current in narrow films of tin nearT
c
with the results from microscopic theory shows good agreement. Nonequilibrium effects become important when the frequency becomes of the order of the inverse inelastic relaxation time
E
–1
(k
B
T
c
3
/
D
2
) (D is the Debye temperature) even if remains well below the gap frequency 0(T)/. 相似文献
2.
A. Postelnicu 《Acta Mechanica》2001,146(1-2):73-86
Summary The paper deals with the aerodynamic analysis of flexible airfoils, based on a quasi-lattice vortex method (QVLM). The analysis is formulated in matrix form and leads, as in other similar studies, to a linear algebraic system when the angle of attack is nonzero, and to an eigenvalue problem when the incidence angle is zero. The aerodynamic characteristic curvesC
L
-,C
m
- are presented. Finally, the airfoil shapes for several values of the tension coefficient and angles of attack are drawn. The results obtained with the present method are in good agreement with those reported in previous studies and evidentiate the flexibility of the QVLM as applied to flexible airfoils.Notation
A
aerodynamic matrix, defined in QVL method, (8)
-
B
matrix, see Eq. (18)
-
c
chord of airfoil
-
C
matrix defined asAB
-
C
L
lift coefficient, 2L/V
2
c)
-
C
p
moment coefficient, 2M/(V
2
c
2)
-
C
p
pressure coefficient,C
p
=2p/(V
2
)
-
C
T
tension coefficient, 2T/(V
2
c)
-
D
matrix, see Eq. (11)
-
I
unit matrix
-
l
curvilinear length of the flexible airfoil
-
N
number of collocation points on the airfoil shape
-
q
dynamic pressure, V
2
/2
-
T
tension force in the sail
-
V
freestream velocity
-
w
downwash
-
x
nondimensional coordinate,x/c
-
X
i
control points, Eq. (9)
-
X
max
dimensionless position of the maximum camber
-
Y
k
source points, Eq. (9)
-
z
coordinate normal tox axis
-
Z
nondimensional coordinate,z/c
-
Z
s
camber equation in dimensionless form,z
s
/c
-
incidence with respect to the upstream flow velocity
-
column vector of the local curvatures {1, 2,...,
N
}
T
-
nondimensional membrane excess ratio
-
eigenvalue of the problem (23)
-
k
zeroes of the Chebyshev polynomia of the first kind, 1kN
-
column vector of the local slopes, {0, 1, 2,...,
N
}
T
-
column vector, {1, 2,...,
N
}
T
- 0
slope at airfoil leading edge 相似文献
3.
Yu. A. Kirichenko S. M. Kozlov K. V. Rusanov E. G. Tyurina 《Journal of Engineering Physics and Thermophysics》1982,42(1):1-6
The effect of pressure and underheating on the position of the boundary between heat-transfer regimes in liquid helium and hydrogen is investigated.Notation q
heat flux
- p
pressure
- =Ts–T
underheating
- Ts
saturation temperature
- T
temperature of liquid
- T=Twa – T
Ts=Twa – Ts
- Twa
temperature of heat-emitting surface
- A,a, B, b, C
constants
- m, n
indices
- Nu
Nusselt number
- Ra
Rayleigh number
-
thermal conductivity
-
coefficient of cubical expansion
-
kinematic viscosity
- g
acceleration
-
standard deviation
Indices 01
conditions of convection-boiling transition
- 02
conditions of boiling-convection transition
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 42, No. 1, pp. 5–11, January, 1982. 相似文献
4.
A numerical model for layered composite structures based on a geometrical nonlinear shell theory is presented. The kinematic is based on a multi-director theory, thus the in-plane displacements of each layer are described by independent director vectors. Using the isoparametric apporach a finite element formulation for quadrilaterals is developed. Continuity of the interlaminar shear stresses is obtained within the nonlinear solution process. Several examples are presented to illustrate the performance of the developed numerical model.List of symbols
reference surface
-
convected coordinates of the shell middle surface
-
i
coordinate in thickness direction
-
i
h
thickness of layer i
- Xo
position vector of the reference surface
-
iXo
position vector of midsurface of layer i
- t
k
orthonormal basis system in the reference configuration
-
i
a
k
orthonormal basis system of layer i
- iW
axial vector
- Ro
orthonormal tensor in the reference configuration
-
i
R
orthonormal tensor of layer i
-
i
Cauchy stress tensor
-
i
P
First Piola-Kirchhoff stress tensor
-
i
q
vector of interlaminar stresses
-
i
n,
i
m
vector of stress resultants and stress couple resultants
-
v
x
components of the normal vector of boundary
-
i
N,
i
Q,
i
M
stress resultants and stress couple resultants of First Piola-Kirchhoff tensor
-
stress resultants and stress couple resultants of Second Piola-Kirchhoff tensor
-
i
,
i
,
i
strains of layer i
- K
transformation matrix
- uo
displacement vector of layer 1
-
i
local rotational degrees of freedom of layer i 相似文献
5.
The dielectric properties of chemically vapour-deposited (CVD) amorphous and crystalline Si3N4 were measured in the temperature range from room temperature to 800° C. The a.c. conductivity (
a.c.) of the amorphous CVD-Si3N4 was found to be less than that of the crystalline CVD-Si3N4 below 500° C, but became greater than that of the crystalline CVD-Si3N4 over 500° C due to the contribution of d.c. conductivity (
d.c.). The measured loss factor () and dielectric constant () of the amorphous CVD-Si3N4 are smaller than those of the crystalline CVD-Si3N4 in all of the temperature and frequency ranges examined. The relationships of
n-1, (-
)
n-1 and/(-
) = cot (n/2) (were observed for the amorphous and crystalline specimens, where is angular frequency andn is a constant. The values ofn of amorphous and crystalline CVD-Si3N4 were 0.8 to 0.9 and 0.6 to 0.8, respectively. These results may indicate that the a.c. conduction observed for both of the above specimens is caused by hopping carriers. The values of loss tangent (tan) increased with increasing temperature. The relationship of log (tan) T was observed. The value of tan for the amorphous CVD-Si3N4 was smaller than that of the crystalline CVD-Si3N4. 相似文献
6.
V. A. Domovtsev 《Journal of Engineering Physics and Thermophysics》1984,47(1):787-790
A method is described for measuring the temperature of a non-steady-state gas flow with a thermocouple which is an inertial component of the first order.Notation T*f
non-steady-state gas flow temperature
- Tt
thermosensor temperature
-
thermal inertia factor of thermosensor
-
time
- C
total heat capacity of thermosensor sensitive element
- S
total heat-exchange surface between sensitive element and flow
-
heat-liberation coefficient
-
temperature distribution nonuniformity coefficient in sensitive element
- Re, Nu, Pr, Bi, Pd
hydromechanical and thermophysical similarity numbers
- P*
total flow pressure
- P
static flow pressure
- T*
total flow temperature
- dt
sensitive element diameter
- w
gas flow velocity
-
flow density
-
flow viscosity
- f
flow thermal conductivity
- k
gas adiabatic constant
- R
universal gas constant
- M
Mach number
- T
thermodynamic flow temperature
- o, o
and values at T=288°K
- A, m, n, p, r
coefficients
- c
heat-liberation coefficient due to colvection
- r
heat-liberation coefficient due to radiation
- b
emissivity of sensitive element material
-
Stefan-Boltzmann constant
- Te
temperature of walls of environment
- c, r, tc
thermosensor thermal inertia factors due to convective, radiant, and conductive heat exchange
- L
length of sensitive element within flow
-
a
thermal diffusivity of sensitive element material
- t
thermal conductivity of sensitive element material
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 47, No. 1, pp. 59–64, July, 1984. 相似文献
7.
A kinetic analysis of the isothermal nitridation of high-purity oxide-free silicon powder is described. The kinetic analysis suggests that the and polymorphs of Si3N4 are formed by separate and parallel reaction paths. This analysis provides for the decoupling and quantitative kinetic interpretation of- and-Si3N4 formation reactions. Consistent with existing microstructural and thermodynamic evidence, the-forming reaction is shown to obey a first-order rate law, whereas a phase-boundary controlled rate law describes the-forming reaction. A kinetic model employing these rate laws is developed and is used to predict the/ phase ratio as a function of isothermal reaction temperature and extent of reaction. The/ phase ratios so obtained are shown to be in good agreement with experimental observations made under a variety of reaction conditions. 相似文献
8.
Summary One-dimensional stress and temperature fields in a suddenly loaded and/or heated semi-infinite rod of nonlinear thermoviscoelastic material are studied using coupled thermomechanical theory. The transport of heat is governed by the modified Fourier heat conduction law, and thus proceeds by wave propagation rather than by diffusion. The application of thermal and mechanical disturbances at the end of the rod gives rise to two wave fronts along which these disturbances propagate. Field solutions for the stress and temperature are obtained by numerical integration along the five characteristics of the governing equations, and results are presented for several linear and nonlinear viscoelastic models.
Notation C specific heat at constant stress - E Young's modulus - J integer as an indication of position - K integer for the condensation of computer storage, Eq. (42) - k isotropic thermal conductivity - nondimensional material constants - M number of nonlinear memory integrals, Eq. (2) - N number of components of strain, Eq. (7) - n steady creep power, Eq. (2) - Q one-dimensional heat flux, Eq. (1) - q i transient creep powers, Eq. (2) - T temperature - T 0 constant reference temperature - t time - time scale for nondimensionalization - V 1,V 2 coupled wave speeds, Eq. (6a) - uncoupled elastic mechanical wave speed - uncoupled thermal wave speed - v particle velocity - x space coordinate - coefficient of thermal expansion - , positive nondimensional quantities governing the wave speeds, Eqs. (5) - one-dimensional strain - 1 linear elastic strain, Eq. (7b) - 2 steady creep strain, Eq. (7c) - i ,i=3, ...,N transient creep strains, Eq. (7d) - T thermal strain, Eq. (7e) - =T–T 0 temperature increment relative to constant reference temperatureT 0 - 0 input temperature discontinuity - ,µ i material constants, Eq. (2) - mass density - one-dimensional stress - i input stress discontinuity - relaxation time of heat conduction, Eq. (1) - i retardation time of transient creep, Eq. (2) - [] j ,j=1, 2 indicates a discontinuity across the leading and lagging wave fronts respectively - (–) indicates nondimensional variables and parameters (drooped after Eq. (9)) With 12 FiguresThis research was supported in part by the Office of Naval Research under Contract No. N00014-75-C-0302. 相似文献
Einige Ergebnisse zum eindimensionalen, gekoppelten, nichtlinearen Wellenausbreitungsproblem mit zweitem Schall
Zusammenfassung Eindimensionale Spannungs- und Temperaturfelder in einem plötzlich belasteten und/oder erwärmten, halbunendlichen Stab aus nichtlinearem, viskoplastischen Material werden mit Hilfe der gekoppelten thermodynamischen Theorie untersucht. Der Wärmetransport gehorcht dem modifizierten Fourierschem Wärmeleitungsgesetz und erfolgt daher eher durch Wellenausbreitung als durch Diffusion. Die Aufbringung thermischer oder mechanischer Störungen am Ende des Stabs läßt zwei Wellenfronten entstehen, mit welchen die Störungen fortschreiten. Feldlösungen für Spannungen und Temperatur werden durch numerische Integration längs der fünf Charakteristiken der beschreibenden Gleichungen erhalten und die Resultate für einige lineare und nichtlineare viskoelastische Modelle angegeben.
Notation C specific heat at constant stress - E Young's modulus - J integer as an indication of position - K integer for the condensation of computer storage, Eq. (42) - k isotropic thermal conductivity - nondimensional material constants - M number of nonlinear memory integrals, Eq. (2) - N number of components of strain, Eq. (7) - n steady creep power, Eq. (2) - Q one-dimensional heat flux, Eq. (1) - q i transient creep powers, Eq. (2) - T temperature - T 0 constant reference temperature - t time - time scale for nondimensionalization - V 1,V 2 coupled wave speeds, Eq. (6a) - uncoupled elastic mechanical wave speed - uncoupled thermal wave speed - v particle velocity - x space coordinate - coefficient of thermal expansion - , positive nondimensional quantities governing the wave speeds, Eqs. (5) - one-dimensional strain - 1 linear elastic strain, Eq. (7b) - 2 steady creep strain, Eq. (7c) - i ,i=3, ...,N transient creep strains, Eq. (7d) - T thermal strain, Eq. (7e) - =T–T 0 temperature increment relative to constant reference temperatureT 0 - 0 input temperature discontinuity - ,µ i material constants, Eq. (2) - mass density - one-dimensional stress - i input stress discontinuity - relaxation time of heat conduction, Eq. (1) - i retardation time of transient creep, Eq. (2) - [] j ,j=1, 2 indicates a discontinuity across the leading and lagging wave fronts respectively - (–) indicates nondimensional variables and parameters (drooped after Eq. (9)) With 12 FiguresThis research was supported in part by the Office of Naval Research under Contract No. N00014-75-C-0302. 相似文献
9.
Neutron scattering experiments on La2–x
Sr
x
CuO4 (LSCO) have revealed the incommensurate antiferromagnetic peaks do not lie exactly on the symmetry axes (q
x=± and q
y=±), but, are slightly shifted from them. In this paper, a scenario is presented for such shift in terms of the anisotropy of t (next-nearest-neighbor hopping integral on the square lattice) in the slave-boson scheme of the two-dimensional t-J model. Since the predictions of the present theory are different from those based on the spin-charge stripes hypothesis, further studies of the shift may clarify the factor responsible for the incommensurate antifcrromagnetic fluctuations in LSCO systems. 相似文献
10.
Summary The tangent modulus tensor, denoted as
, plays a central role in finite element simulation of nonlinear applications such as metalforming. Using Kronecker product notation, compact expressions for
have been derived in Refs. [1]–[3] for hyperelastic materials with reference to the Lagrangian configuration. In the current investigation, the corresponding expression is derived for materials experiencing finite strain due to plastic flow, starting from yield and flow relations referred to the current configuration. Issues posed by the decomposition into elastic and plastic strains and by the objective stress flux are addressed. Associated and non-associated models are accommodated, as is plastic incompressibility. A constitutive inequality with uniqueness implications is formulated which extends the condition for stability in the small to finite strain. Modifications of
are presented which accommodate kinematic hardening. As an illustration,
is presented for finite torsion of a shaft, comprised of a steel described by a von Mises yield function with isotropic hardening.Notation B
strain displacement matrix
- C=F
T
F
Green strain tensor
-
compliance matrix
- D=(L+L
T
)/2
deformation rate tensor
-
D
fourth order tangent modulus tensor
-
tangent modulus tensor (second order)
-
d
VEC(D)
-
e
VEC()
-
E
Eulerian pseudostrain
-
F, F
e
,F
p
Helmholtz free energy
- F=x/X
deformation gradient tensor
-
f
consistent force vector
-
residual function
- G
strain displacement matrix
-
h
history vector
-
h
time interval
-
H
function arising in tangent modulus tensor
-
I, I
9
identity tensor
-
i
VEC(I)
-
k
0,k
1
parameters of yield function
-
K
g
geometric stiffness matrix
-
K
T
tangent stiffness matrix
-
k
k
kinematic hardening coefficient
-
J
Jacobian matrix
-
L=v/x
velocity gradient tensor
-
m
unit normal vector to yield surface
- M
strain-displacement matrix
- N
shape function matrix
-
n
unit normal vector to deformed surface
-
n
0
unit normal vector to undeformed surface
-
n
unit normal vector to potential surface
-
r, R, R
0
radial coordinate
-
s
VEC()
-
S
deformed surface
-
S
0
undeformed surface
-
t
time
-
t, t
0
traction
-
t
VEC()
-
VEC(
)
-
t
VEC()
-
t
r
reference stress interior to the yield surface
-
t
t–t
r
-
T
kinematic hardening modulus matrix
-
u=x–X
displacement vector
- U
permutation matrix
-
v=x/t
particle velocity
-
V
deformed volume
-
V
0
undeformed volume
-
X
position vector of a given particle in the undeformed configuration
-
x(X,t)
position vector in the deformed configuration
-
z, Z
axial coordinate
-
vector of nodal displacements
- =(F
T
F–I)/2
Lagrangian strain tensor
-
history parameter scalar
- ,
azimuthal coordinate
-
elastic bulk modulus
-
flow rule coefficient
-
twisting rate coefficient
-
elastic shear modulus
-
iterate
-
Second Piola-Kirchhoff stress
-
Cauchy stress
-
Truesdell stress flux
-
deviatoric Cauchy stress
-
Y, Y
yield function
-
residual function
-
plastic potential
-
X, Xe, Xp
second order tangent modulus tensors in current configuration
-
X, Xe, Xp
second order tangent modulus tensors in undeformed configuration
- (.)
variational operator
- VEC(.)
vectorization operator
- TEN(.)
Kronecker operator
- tr(.)
trace
-
Kronecker product 相似文献
11.
A new method to measure the thermal diffusivity of liquids is presented. It requires determination of the time dependence of the thermal expansion of the liquid when it is subjected to a heat source at the top of the cell containing the liquid. The high accuracy of the method (about 3%) is due to an essential reduction of convective currents and also to the absence of temperature detectors, which generally introduce unwanted perturbations on the thermal Field.Nomenclature
Thermal conductivity
-
c
Specific heat
-
Density
-
c = specific heat x density
-
h
Newton coefficient
-
Thermal diffusivity
-
T, 0
Temperature
-
tV
Electric signal
-
Calibration coefficient
- exp, th
Volume change of the liquid 相似文献
12.
I. G. Borovskoi A. B. Vorozhtsov E. A. Kozlov 《Journal of Engineering Physics and Thermophysics》1988,54(5):534-539
The article presents results of a numerical solution of a nonsteady problem on the free discharge of a mixture of gases from a hemispherical volume with allowance for thermal decomposition of heat-insulating materials.Notation V
volume
- S
area
- t
- P
p
- T
- u
v
- Q
q, dimensional and dimensionless time, pressure, temperature, TIM decomposition rate, and heat flux
-
adiabatic exponent
- R
gas constant
-
density
- H
specific enthalpy
- c
specific heat
-
thermal conductivity
- , , s
dimensionless complexes
-
coefficient expressing the radiative properties of the gas medium and the heat-transfer surface
-
Stefan-Boltzmann constant
Indices 0
initial state and scale factors
- s
surface
-
coke
- M
TIM material
- P
pyrolysis front
- A
ablation front
- v
volatile degradation products
-
adiabatic conditions
- c
completion of discharge
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 54, No. 5, pp. 787–793, May, 1988. 相似文献
13.
S. P. Detkov 《Journal of Engineering Physics and Thermophysics》1971,20(5):565-570
Necessary conditions are established for the validity of the Hottel formulas for the absorptivity relative to black radiation. The formulas are used in describing the absorption of a badly mixed medium and for nonblack incident radiation.Notation x
ray path in mat
- p, P
partial and total pressure
- Peff
effective broadening pressure
- T, T0
gas and wall temperatures, °K
- T*, Ti
selected temperature values
- Tc
weighted-mean temperature
- a0
absorptivity of the gas for black radiation
-
a
same for a flux with nonblack spectrum
-
emissivity
- m, u, n, ,
power exponents
-
i
0j
Planck function for the center of the band, cm · W/m2 · sr
- Ij
incident flux intensity at the center of the band j, cm · W/m2 · sr
- I
integrated incident flux intensity, W/m2 · sr
- Aj
integral absorption (equivalent width) of band f, cm–1
- j
mean absorption in the band
-
wave number, cm–1
-
0
position of the band center
-
j
width parameter
-
effj
effective width
-
j
total width of the band j, cm–1
- Dj
mean transmissivity in the band j
- S
integrated line intensity, cm–1/mat
- d, b
spacing between lines and their half-width, cm–1
- Sj
integrated intensity of the band j
- L
Landenburg and Reiche functions
-
spectral absorption coefficient, mat–1
- (T)
dimensionless function
- ci
dimensionless number
- R*, Rc
general notation for parameters averaged over the band and for Tc
- E
Elsasser function
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 20, No. 5, pp. 802–808, May, 1971. 相似文献
14.
A. E. Koshelev 《Journal of Low Temperature Physics》2005,139(1):111-125
No Heading In presence of the Josephson vortex lattice in layered superconductors, small c-axis magnetic field penetrates in the form of vortex chains. In general, structure of a single chain is determined by the ratio of the London [] and Josephson [J] lengths, = /J. The chain is composed of tilted vortices at large s (tilted chain) and at small s it consists of crossing array of Josephson vortices and pancake-vortex stacks (crossing chain). We study chain structures at the intermediate s and found two types of phase transitions. For 0.6 the ground state is given by the crossing chain in a wide range of pancake separations a [2–3]J. However, due to attractive coupling between deformed pancake stacks, the equilibrium separation can not exceed some maximum value depending on the in-plane field and . The first phase transition takes place with decreasing pancake-stack separation a at a = [1 – 2]J, and rather wide range of the ratio , 0.4 0.65. With decreasing a, the crossing chain goes through intermediate strongly-deformed configurations and smoothly transforms into the tilted chain via the second-order phase transition. Another phase transition occurs at very small densities of pancake vortices, a [20 – 30]J, and only when exceeds a certain critical value 0.5. In this case small c-axis field penetrates in the form of kinks. However, at very small concentration of kinks, the kinked chains are replaced with strongly deformed crossing chains via the first-order phase transition. This transition is accompanied by a very large jump in the pancake density.PACS numbers: 74.25.Qt, 74.25.Op, 74.20.De 相似文献
15.
E. M. Godzhaev A. M. Nazarov Kh. S. Khalilova A. M. Suleimanova 《Inorganic Materials》2001,37(11):1104-1105
The thermal expansion coefficient () and isothermal compressibility (
T
) of TlIn1 – x
Nd
x
Se2(0 x 0.08) crystals were measured between 77 and 400 K. In the range 77–160 K, both and
T
increase with temperature, the increase in being much steeper. At higher temperatures, and
T
change very little. The observed composition dependences of and
T
are interpreted in terms of energy-band structure. 相似文献
16.
Prof. Dr. H. F. Bauer 《Acta Mechanica》1990,84(1-4):1-12
Summary The response of a solidly rotating liquid bridge consisting of inviscid liquid is determined for pitch excitation about its undisturbed center of mass. Free liquid surface displacement and velocity distribution has been determined in the elliptic (>20) and hyperbolic (<20) excitation frequency range.List of symbols
a
radius of liquid column
-
h
length of column
-
I
1
modified Besselfunction of first kind and first order
-
J
1
Besselfunction of first kind and first order
-
r, ,z
cylindrical coordinates
-
t
time
-
u, v, w
velocity distribution in radial-, circumferential-and axial direction resp.
-
mass density of liquid
-
free surface displacement
-
velocity potential
- 0
rotational excitation angle
- 0
velocity of spin
-
forcing frequency
- 1n
natural frequency
-
surface tension
-
acceleration potential
-
for elliptic range >20
-
for hyperbolic range >20 相似文献
17.
The interaction between a dislocation and the impurity in KCl: Mg2+ (0.035 mol% in the melt) was investigated at 77–178 K with respect to the two models: one is the Fleischer's model and the other the Fleischer's model taking account of the Friedel relation. The latter is termed the F-F. The dependence of strain-rate sensitivity due to the impurities on temperature for the specimen was appropriate to the Fleischer's model than the F-F. Furthermore, the activation enthalpy, H, for the Fleischer's model appeared to be nearly proportional to the temperature in comparison with the F-F. The Friedel relation between effective stress and average length of the dislocation segments is exact for most weak obstacles to dislocation motion. However, above-mentioned results mean that the Friedel relation is not suitable for the interaction between a dislocation and the impurity in the specimen. Then, the value of H(T
c) at the Fleischer's model was found to be 0.61 eV. H(T
c) corresponds to the activation enthalpy for overcoming of the strain field around the impurity by a dislocation at 0 K. In addition, the Gibbs free energy, G
0, concerning the dislocation motion was determined to be between 0.42 and 0.48 eV on the basis of the following equation ln / = G
0/(kTp0)1 – (T/T
c)1/2
–1(T/T
c)1/2 + ln 0/where k is the Boltzmann's constant, T the temperature, T
c the critical temperature at which the effective stress due to the impurities is zero, p0 the effective shear stress without thermal activation, and 0 the frequency factor. 相似文献
18.
N. F. Bondarenko E. Z. Gak M. Z. Gak É. E. Rokhinson 《Journal of Engineering Physics and Thermophysics》1978,35(5):1317-1323
It is known that in nonuniform magnetic fields the precavitation properties of aqueous media change, leading to an increase in the irreversible physicochemical changes.Notation
l
length of zone II
- D and d
diameters of tubes I, III, and II
- pI, pII, pIII
pressures in regions I, II, and III
- pcr
critical pressure at which cavitation occurs
- pcr and p
cr
0
critical pressures in the magnetic field and when there is no magnetic field
- [VI, VII, VIII]
velocities of the liquid in regions I, II, and III
- VII, lim
velocity of the liquid at which breakdown of the hydrated layer occurs for a certain value of the induction
- Vcr and V
cr
0
critical velocities at which cavitation occurs in the magnetic field and when there is no magnetic field
- pa
atmospheric pressure
- psv
saturation-vapor pressure at the given temperature
-
density of the liquid
-
kinematic viscosity
- Re
Reynolds number
- Recr
critical Reynolds number
- cgf and cgd
concentrations of free and dissolved gases in the magnetic field and when there is no magnetic field
- cgf and cgd, and c
gf
0
and c
gd
0
concentrations of free and dissolved gases in the magnetic field and when there is no magnetic field
-
sc
space-charge density
-
electrical conductivity in the volume of the liquid
- b
electrical conductivity in the boundary layer
-
l
, g, d
dielectric constants of the liquid in the volume, of the gas in the bubbles, and of the diffusion layer
- j, jb, ji, and jT
current density of the general, boundary layer, induced and current flow
- fMHD and fEHD
volume forces of magnetohydrodynamic and electrodynamic nature (per unit volume)
- pMHD
pressure in the liquid due to the action of the magnetohydrodynamic forces
- 0
limiting shear stress in the liquid
- B
magnetic induction
- E
electric field strength in the volume of the liquid
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 35, No. 5, pp. 842–850, November, 1978. 相似文献
19.
M. M. Talianker 《Journal of Materials Science》1982,17(11):3097-3100
The athermal transformation in Zr-2 at.% Nb alloy has been investigated by transmission electron microscopy. Analysis of the selected-area diffraction pattern has shown that the orientation relationships between the omega and the parent-phase in quenched Zr-2 at.% Nb alloy are the same as have been previously observed for the reaction in pure zirconium. Thus it was deduced that the direct transition has taken place in the alloy during cooling. The-originated -particles were visualized using the dark-field technique. The formation of the athermal omega in the-region of-stabilized Zr-Nb alloy is discussed in terms of the relative positions of the free energy equilibrium curvesT
0
,T
0
,T
0
and the correspondingM
s
,M
s
andT
s
start curves. It is concluded that the omega phase can occur over a much wider range of alloy compositions than is usually recognized on the basis of transformation data. 相似文献
20.
Measurements of the acoustic attenuation and dispersion in liquid 3He-4He mixtures near the superfluid transition T
(x) are reported. The frequency range is /2gp=1–45 MHz and the 3He mole fraction X of the mixtures is 0.007, 0.05, 0.15, and 0.36. Comparisons are made with the measurements of Buchal and Pobell for similar mixtures obtained in the kHz region, and on the whole, the consistency between the two experiments is very satisfactory. An analysis is then performed using both the kHz and MHz data. In the normal phase, where the energy dissipation is caused by order parameter fluctuations having a lifetime
F
, the attenuation data can all be scaled according to the expression = (T
)f(F. Here (T
)1+y, with y being a function of the mole fraction X and F(T–T
)–x, with x increasing weakly with X. In the superfluid phase, we attempt a similar scaling representation, which is found to be fairly successful, but where x(T\s-T
) is roughly 15% larger than x(T>T
). In the superfluid phase we also analyze the attenuation data, assuming the additivity of relaxation and fluctuation-dissipation mechanism, and discuss the relaxation times so derived. In contrast to the attenuation, the dispersion data cannot be brought satisfactorily into a scaling representation. However, at T
, we find U()-U(0)y as predicted by Kawasaki, where y is in good agreement with the values from attenuation experiments.Supported by a grant from the National Science Foundation. 相似文献