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1.
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
2.
O. M. Al'chikova Kh. A. Akhmedzhanov V. G. Ben'kovskii V. G. Gladov 《Journal of Engineering Physics and Thermophysics》1967,12(6):432-435
Some general regularities of dispersion of a gas emerging from a nozzle submerged in a liquid are considered. A condition for establishment of the so-called maximum dispersion state is formulated.Notation 0
coefficient of surface tension at the liquidgas boundary
-
contact angle of wetting of the nozzle material surface by the liquid
- pat
atmospheric pressure
- p
air pressure
-
density of the liquid
- g
gravitational acceleration
- h
height of the liquid column
- 1, and g
dynamic viscosity coefficients of the liquid and gas, respectively
- R and r
radii of the bubble and nozzle, respectively
- Q and F
dimensionless criteria
-
, , , , and
undetermined coefficients
-
ratio of the circumference of a circle to its diameter 相似文献
3.
Thermally stimulated current (TSC) discharges in open circuit of amorphous poly(ethylene terephthalate) (PET) corona-charged electrets show a heteropolar relaxation at 87 °C, 1 between and peaks. This relaxation tends to become homopolar when the sample is annealed at temperatures below the glass transition temperature. This is due to the formation of a trapped charge density on the surface of the material that originates, during the TSC discharge, a current that counteracts the one that results in 1 This trapping effect, which initially is null, increases with annealing due to the rise in resistivity. On the other hand, TSC discharges in short-circuited annealed samples result in a heteropolar peak, *, that corresponds to 1 The area of * increases with the annealing time in a bounded way. This peak is related to the formation of thermal nuclei (embryos) in the bulk of the material that act as heterogeneities. This suggests that 1 is associated with a barrier-type polarization. If the annealed sample is heated to temperatures above the glass transition temperature, the tendency to the inversion of 1 vanishes and * disappears, whereas and are modified. This suggests that relaxation is related to a Maxwell-Wagner-Sillars effect. 相似文献
4.
V. A. Gorodtsov 《Journal of Engineering Physics and Thermophysics》1980,39(4):1062-1065
Energy losses to radiation of internal waves during the vertical motion of a point dipole in two-dimensional and three-dimensional cases are computed.Notation o(z), po(z)
density and pressure of the ground state
- z
vertical coordinate
- v, p,
perturbed velocity, pressure, and density
- H(d 1n o/dz)–1
characteristic length scale for stratification
- N=(gH–1–g2c
o
–2
)1/2
Weisel-Brent frequency
- g
acceleration of gravity
- co
speed of sound
-
vertical component of the perturbed velocity
- V
vector operator
- k
wave vector
-
frequency
- d
vector surface element
- W
magnitude of the energy losses
- (t), (r) (x)(y)(z)
Dirac functions
- vo
velocity of motion of the source of perturbations
- d
dipole moment of the doublet
- o,l
length dimension parameters
- o
intensity of the source
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 4, pp. 619–623, October, 1980. 相似文献
5.
Deformation approach to the evaluation of the period of initiation and growth of fatigue macrocracks
We performed experimental investigation of the opening displacements of the contours of stress concentrators (notches and cracks) for various amplitudes of cyclic loading. On the basis of experimental results, we propose a new deformation parameter
t
which is a function of the notch (crack) tip opening displacement , namely,
t
/(+d*), where is the radius of the tip of the notch andd* is the characteristic size of the prefracture zone. It is shown that this parameter uniquely determines the number of cyclesN
l to the initiation of a fatigue macrocrack independently of the geometry of the specimens and stress concentrators in elastic and elastoplastic materials, i.e., the dependence of
t
onN
1 is a characteristic of the material. It is experimentally demonstrated that this dependence enables one to quantitatively describe the process of fatigue fracture both in the stage of initiation of macrocracks and their propagation.Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 31, No. 5, pp. 7–21, September – October, 1995. 相似文献
6.
B. A. Kolovandin N. N. Luchko T. V. Sidorovich V. A. Sosinovich 《Journal of Engineering Physics and Thermophysics》1982,42(1):36-40
The problem of universal simulation of the dynamics of a turbulent velocity field (universal in the sense of arbitrary values of the Reynolds turbulence number) is treated on the basis of the moment model in the second approximation.Notation ¯q2
i
2
double the kinetic turbulence energy
-
u
2
=5v¯q2/u
Taylor turbulence scale squared
- u=v1/xk)2>
kinetic-energy dissipation function
- NRe,=¯q2u /
Reynolds turbulence number
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 42, No. 1, pp. 46–52, January, 1982. 相似文献
7.
Vl. N. Smirnov 《Journal of Engineering Physics and Thermophysics》1981,40(3):299-304
Thermoelasticity equations in stresses are derived in this paper for a Cosserat medium taking into account the finiteness of the heat propagation velocity. A theorem is proved on the uniqueness of the solution for one of the obtained systems of such equations.Notation
u
displacement vector
-
small rotation vector
-
absolute temperature
-
0
initial temperature of the medium
-
relative deviation of the temperature from the initial value
-
, , , , , ,, m
constants characterizing the mechanical or thermophysical properties of the medium
-
density
-
I
dynamic characteristic of the medium reaction during rotation
- k
heat conduction coefficient
-
0
a constant characterizing the velocity of heat propagation
-
X
external volume force vector
-
Y
external volume moment vector
- w
density of the heat liberation sources distributed in the medium
-
E
unit tensor
-
T
force stress tensor
- M
moment stress tensor
-
nonsymmetric strain tensor
-
bending-torsion tensor
- s
entropy referred to unit volume
- V
volume occupied by the body
-
surface bounding the body
- (T)ki, (M)ki
components of the tensorsT andM
-
q
thermal flux vector
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 40, No. 3, pp. 482–488, March, 1981. 相似文献
8.
Flux motion in anisotropic type-II superconductors near Hc
2 is studied in the framework of the time-dependent Ginzburg-Landau (TDGL) theory for the case that the average flux densityB is oriented in an arbitrary direction relative to the principal axes of the sample. The linearized TDGL equation for a uniformly translating order parameter is solved and expressions for all elements of the flux-flow resistivity tensor ij (including the off-diagonal Hall elements) are obtained. The diagonal elements ii show the angular scaling property that ii(B) = ii(B/Hc
2(, ø)), whereas the Hall elements ij (i j) have additional angular dependences that are not contained in Hc2. For the case that the normal state Hall elements
ij
(n)
B
k with i j k, the ratios ij/
ij
(n)
are functions of B/Hc2 (, ) only. 相似文献
9.
W. N. Kang Kijoon H. P. Kim Hyeong-Jin Kim Eun-Mi Choi Heon Jung Kim Hyun-Sook Lee Sung-Ik Lee 《Journal of Low Temperature Physics》2003,131(5-6):1075-1084
We have measured the Hall resistivity,
xy
, and the longitudinal resistivity,
xx
, in superconducting MgB2 thin films in a mixed-state while changing the magnetic field and the current density. A Hall scaling behavior without the anomalous Hall effect was observed with a exponent of 2.0±0.1 in
xy
=A
xx
. This exponent is observed to be constant, i.e., independent of magnetic field, temperature, and current density. 相似文献
10.
Summary. The boundary-layer similarity flow driven over a semi-infinite permeable flat plate by a power-law shear with asymptotic velocity profile U(y)=y(y,>0) is considered in the presence of lateral suction or injection of the fluid (y denotes the coordinate normal to the plate). The analytically tractable cases =–2/3 and =–1/2 are examined in detail. It is shown that while for =–2/3 the adjustment of the flow over an impermeable plate to the power-law shear is not possible, in the permeable cases the presence of suction allows for a family of boundary-layer solutions with the proper algebraic decay. The value of the skin friction corresponding to this family of solutions is given by the parameter s=93/(4fw), where fw denotes the suction parameter. In the limiting case of a vanishing suction and a properly vanishing value of the parameter (such that s=finite), this family of algebraically decaying solutions goes over into the (exponentially decaying) Glauert-jet. In the case =–1/2, solutions showing the proper algebraic decay were found both for suction ( fw > 0) and injection ( fw<0) in the whole range –<fw<+. In this case the skin friction parameters s=22/3 is independent of the suction/injection parameter fw. 相似文献
11.
A. M. Mamedov 《Journal of Engineering Physics and Thermophysics》1980,39(2):897-900
Using two liquids-water and toluene — as an example, the author determines the dependence of the coefficient of thermal conductivity on the speed of sound and isobaric molar heat capacity for high state parameters.Notation
coefficient of thermal conductivity
- u
speed of sound
-
S
same for a saturated liquid
- c
isobaric molar heat capacity
-
density
- ps
same, for a saturated liquid
- p
pressure
- ps
same, for a saturated liquid
- R
gas constant
- T
absolute temperature
-
x
coefficient of thermal activity
-
x
s
same, for a saturated liquid
- L,
constants in Eqs. (1) and (2)
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 39, No. 2, pp. 311–314, August, 1980. 相似文献
12.
K. A. Moler D. J. Baar Ruixing Liang W. N. Hardy A. Kapitulnik 《Journal of Superconductivity》1995,8(5):571-574
The total specific heat of YBa2Cu3O6.95 single crystals includes contributions from phonons and spin-1/2 particles, as well as electronic contributions. The electronic specific heat is described by a quadratic term T2 in zero field and a linear term [(0)+(H)]T which is increased when a magnetic field H is applied perpendicular to the CuO2 planes. In agreement with d-wave superconductivity, we find that n/Tc and (H)n(H/Hc2)1/2, where n is the coefficient of the normal-state linear term. The H1/2 dependence of the density of states at the Fermi level was predicted by G. Volovik for lines of nodes in the gap: the quasiparticles which contribute to this density of states are close to the nodes in momentum space and are located outside the vortex core. 相似文献
13.
R. Tidecks 《Journal of Low Temperature Physics》1985,58(5-6):439-449
Based on the assumption that a phase-slip center in a clean quasi-one-dimensional superconductor excites a collective oscillation, the time-averaged value of the electrochemical potential of quasiparticles is calculated. At larger distances from the phase-slip center, swings below (or above) the electrochemical potential
p
of the Cooper pairs. This makes it possible to understand the unexpected results of previous measurements. 相似文献
14.
R. Ocaña A. Taldenkov P. Esquinazi Y. Kopelevich 《Journal of Low Temperature Physics》2001,123(3-4):181-196
We have performed high-resolution measurements of the magnetic field (0 TB9 T) and temperature (10 KT<140 K) dependence of the longitudinal and transverse Hall thermal conductivity of a twinned YBa2Cu3O6.95 single crystal. We have used and compared two recently published methods to extract the thermal Hall angle H(T, B). Our results indicate that cot(H) varies quite accurately as T4 in the intermediate temperature range 0.3c. It shows a well defined minimum at Tm20 K which resembles that observed in the c-axis microwave conductivity. The electronic part of the longitudinal and the transverse thermal conductivity show the scaling behavior for transport properties predicted for d-wave superconductors in the temperature range 18 KT30 K. 相似文献
15.
V. A. Borodulya Yu. G. Epanov Yu. S. Teplitskii V. I. Kovenskii 《Journal of Engineering Physics and Thermophysics》1981,41(3):972-977
A method is proposed for the joint determination of the coefficients of horizontal particle diffusion and external heat exchange in a stagnant fluidized bed.Notation cf, cs, cn
specific heat capacities of gas, particles, and nozzle material, respectively, at constant pressure
- D
effective coefficient of particle diffusion horizontally (coefficient of horizontal thermal diffusivity of the bed)
- d
equivalent particle diameter
- dt
tube diameter
- H0, H
heights of bed at gas filtration velocities u0 and u, respectively
- Ha
height of active section
-
l
width of bed
- L
tube length
-
l
o
width of heating chamber
- N
number of partition intervals
- p=H/H0
expansion of bed
- sn
surface area of nozzle per unit volume of bed
- Sh, Sv
horizontal and vertical spacings between tubes
- tc, t0, ts, tn, tw
initial temperature of heating chamber, entrance temperature of gas, particle temperature, nozzle temperature, and temperature of apparatus walls, respectively
- u0, u
velocity of start of fluidization and gas filtration velocity
- y
horizontal coordinate
-
*,
coefficient of external heat exchange between bed and walls of apparatus and nozzle
- 1, 1, 2, ...
coefficients in (4)
-
thickness of tube wall
- b
bubble concentration in bed
- 0
porosity of emulsion phase of bed
- n
porosity of nozzle
- =(ts – t0)/(tc – t0)
dimensionless relative temperature of particles
- n
coefficient of thermal conductivity of nozzle material
- f, s, n
densities of gas, particles, and nozzle material, respectively
- be=s(1 – 0) (1 – b)
average density of bed
-
time
- max
time of onset of temperature maximum at a selected point of the bed
- R =l
o/l
Fourier number
- Pe = 1
l
2/D
Péclet number
- Bi = /n
Biot number
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 41, No. 3, pp. 457–464, September, 1981. 相似文献
16.
J. Mucha H. Misiorek A. V. Golubkov L. S. Parfenieva I. A. Smirnov 《International Journal of Thermophysics》2003,24(3):859-865
The thermal conductivity () and electrical resistivity () of mixed-valence compound Sm3S4 have been measured in the temperature range 5 to 300 K. The present results and those presented previously [1] for the thermal conductivity between 80 to 850 K are interpreted in terms of the temperature-dependent fluctuating valence of Sm ions. Sm3S4 crystallizes in the cubic Th3P4 structure, and the cations with different valences occupy equivalent lattice sites. Divalent and trivalent Sm ions are randomly distributed in the ratio of 1:2 over all possible crystallographic cation positions (Sm2+
2Sm3+
2S2–
4). The behavior of the Sm3S4 lattice thermal conductivity
ph
is extraordinary since valences of Sm ions are fluctuating (Sm3+Sm2+) with a temperature dependent frequency. In the interval 20 to 50 K (low hopping frequencies),
ph
of Sm3S4 varies as
ph
T
–1 (it is similar to materials with static distribution of cations with different valences): at 95 to 300 K (average hopping frequencies 107 to 1011 Hz),
ph
changes as
ph
T
–0.3 (it is similar to materials with defects). Defects in Sm3S4 appear because of local strains in the lattice by the electrons hopping from Sm2+ ions (with big ionic radii) to Sm3+ ions (with small ionic radii) and back (Sm2+Sm3+), at T>300 K (high hopping frequencies),
ph
becomes similar to materials with homogenous mixed valence states [1]. 相似文献
17.
Z. M. Galasiewicz 《Journal of Low Temperature Physics》1984,57(1-2):123-150
The spin hydrodynamic equations for superfluid3He-B have been obtained for the case of external, time-dependent fields. On the basis of a microscopic approach, expressions are found for additional terms in equations containing these fields. Considering the linear response of the system to the switching on of external fields, formulas are found for suitable Green's functions (magnetization-magnetization, rotation-rotation, magnetization-rotation, rotation-magnetization). The rotation-rotation Green's function has the 1/q
2 singularity characteristic of superfluid systems. Connections between Green's functions lead to relations among kinetic coefficients v, 1, and 2. It is also shown that there is a conserved quantityQ
(B) = div v
s
(B)
that describes sources or magnetic type charges (monopoles) of the superfluid velocity v
s
(B)
. Comparison with the phenomenological approach suggests thatQ
(B) is proportional to a pseudoscalar giving the projection of the spin density onto the vector describing the axis of rotation. 相似文献
18.
The mechanical behaviour of Mg-5.1 wt % Zn alloy single crystals was studied in the 4.2 to 300° K temperature range. Quenched crystals have activation energies and volumes best associated with the cutting of small clusters of Zn atoms by dislocations. Fully hardened crystals contain fine
1 and occasional
2 precipitates with an average
1 interparticle spacing of 330 to 660 Å. Strengthening in these crystals is mainly ascribed to the cutting of
1 particles by dislocations. In the overaged condition
1,
2 and equilibrium particles are present and lead to a considerable temperature-dependence unusual for an overaged condition. Analysis of this temperature-dependence suggests that below 77° K the relatively easy cutting of
1 particles by dislocations takes place in addition to the cutting of
2 and particles. Above 77° K the difficult cutting of
2 and particles alone controls the deformation,
1 being more easily cut with the aid of thermal fluctuations. 相似文献
19.
A. Siginer 《Acta Mechanica》1987,66(1-4):233-249
Summary The free surface motion of a layered medium of liquids in a gravitationally stable configuration, resting on top of a layer of mercury, driven by a torsionally oscillating, cylindrical outer wall is investigated. The non-linear problem in the unknown physical domain is expressed as a series of linear problems in the rest state by means of a domain perturbation method. The flow variables and the stress are expanded into series in terms of the amplitude of the oscillation of the cylinder. The shapes in the mean of the interfaces between layers and the flow field are determined up to second order in the perturbation parameter, the amplitude of the oscillation.Nomenclature
Density
-
Modified pressure field
-
Amplitude of the oscillation
-
Frequency of the oscillation
-
Interfacial value of the surface tension
-
Dynamic viscosity
- , ,
Material functions
-
Complex viscosity
-
Stream function
-
Position vector at timet=
- 1, 2
The first two Rivlin-Ericksen constants
-
Quadratic shear relaxation modulus
- ,t
Time
-
u
Velocity vector
-
u,v,w
Velocity components
-
S
Extra stress tensor
-
h
Interface elevation
-
D
Stretching tensor
-
G
Strain history tensor
-
A
1
The first Rivlin-Ericksen tensor
-
J
Mean curvature
-
p
Pressure
-
t
Unit tangent vector
-
n
Unit normal vector
-
G
Shear relaxation modulus
-
X
Position vector in the rest stateD
0
-
r, ,z
Rest state coordinates
-
x
Position vector in the physical spaceD
-
R, ,Z
Physical space coordinates
-
r
0
Radius of the oscillating cylinder
-
e
r
,e
,e
z
Physical basis vectors inD
0
-
e
R
,e
,e
Z
Physical basis vectors inD
-
Indicates the jump in the enclosed quantity across an interface
With 1 FigurePresented at the Xth Canadian Congress of Applied Mechanics, The University of Western Ontario, London, Ontario, Canada, June 2–7, 1985. 相似文献
20.
The details of structure modification on 2/ interface induced by deformation in a hot-deformed Ti-45Al-10Nb alloy were investigated by conventional and high-resolution transmission electron microscopy. A new type of dislocation ledge containing 1/3[111] partials was identified. The Burgers vectors of these dislocation ledges were determined to be 1/2[110] or 1/2101]. The formation mechanism of this new type of dislocation ledge is discussed. Also, two types of hot deformation induced 2/ interfaces, coherent interfaces with high density of ledges and misoriented semi-coherent 2/ interfacial boundaries were observed. For the misoriented semi-coherent 2 interfaces, the density of dislocation ledges in these interfaces increases with the misoriented angle between the (111)
and (0001)
planes, and 1/3[111] partial dislocations were involved in all the dislocation ledges. The formation mechanism of these deformation-induced 2/ interfaces were discussed related to the role of 2/ interfaces adjusting the deformation as a dislocation sink absorbing the slipping dislocations in the phase. Moreover, misoriented semi-coherent 2 interface related deformation twinning and structure transformation induced by deformation were analyzed and discussed related to the role of 2/ interfaces as a dislocation source during deformation. 相似文献