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1.
Influence of Antiferromagnetic Fluctuations on the Fulde–Ferrell–Larkin–Ovchinnikov State in CeCoIn5
M. Nicklas C. F. Miclea J. L. Sarrao J. D. Thompson G. Sparn F. Steglich 《Journal of Low Temperature Physics》2007,146(5-6):669-680
The Fulde–Ferrell–Larkin–Ovchinnikov (FFLO) state is a spatially inhomogeneous superconducting (SC) phase with a periodically
modulated order parameter predicted to appear in sufficiently clean type-II superconductors, close to the upper critical field,
if the orbital pair breaking is small relative to the Pauli-limiting effect. The heavy-fermion superconductor CeCoIn5 is the first material, where different physical probes show strong experimental evidence pointing to the realization of the
FFLO state, even though strong antiferromagnetic (AFM) spin-fluctuations (SF) are present at atmospheric pressure. To study
the influence of the AFM-SF on the FFLO state we performed heat-capacity experiments under pressure. We utilized a newly developed
miniature piston-cylinder type pressure cell specially suited for measuring small samples at high-magnetic fields and low
temperatures (0 GPa ≤ P ≤ 1.5 GPa, 0 kOe ≤ H ≤ 140 kOe, and 100 mK ≤ T ≤ 4 K). We found the second anomaly inside the SC state
in CeCoIn5 can still be observed with pressure, which suppress the strong AFM-SF. The FFLO phase extends to higher fields
and temperatures on applying pressure while the Pauli-limiting effect is becoming weaker and the SF are suppressed. This reveals
the detrimental effect of the AFM-SF on the FFLO phase stability.
相似文献
2.
L. A. Sosnovskii N. A. Makhutov V. I. Matviatsov A. A. Kebikov 《Strength of Materials》2009,41(1):68-73
The diagram of damage of structural steels under bending and contact loading has been constructed. The criterion of the critical
state of steels is proposed, which corresponds to the formation of incipient surface cracks in the rolling friction zone.
The methods of shortcut estimation of the damaged state of railway rails, which provide prediction of their reliability and
life under service conditions, are proposed. A set of experimental studies is made with objectives to justify the proposed
diagram, criterion and methods.
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Translated from Problemy Prochnosti, No. 1, pp. 88–94, January–February, 2009. 相似文献
3.
We analyze the problem of the stress distribution in an elastic orthotropic medium with an arbitrarily oriented elliptical
crack. To construct the problem solution, the Willis approach is used which is based on the triple Fourier transformation
of spatial variables and Fourier-image of Green’s function for an infinite anisotropic space. The investigation results in
special cases are compared with the data of other authors. The effect of the elliptical crack orientation in an orthotropic
space on the distribution of the stress intensity factors along its contour is studied.
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Translated from Problemy Prochnosti, No. 4, pp. 146–159, July–August, 2007. 相似文献
4.
A. A. Ostsemin 《Strength of Materials》2009,41(4):356-362
The tensile necking in cylindrical and plate specimens is described based on a modification of the Bridgman theory for an
isotropic case. A method of determination of principal stress trajectories in an elliptical tensile neck is put forward, which
involves transformation of the initial coordinate grid by means of conformal mappings. Expressions are derived for the principal
stresses and the radius of curvature of stress trajectories. Based on assumptions that depart from the Bridgman theory, an
approximate analytical solution is obtained for the stress distribution in specimens with an elliptical cross-section. The
new solution belongs to the one-parameter family of solutions which includes the Bridgman’s and Davidenkov–Spiridonova’s solutions.
Translated from Problemy Prochnosti, No. 4, pp. 19–28, July–August, 2009. 相似文献
5.
G. V. Stepanov V. V. Kharchenko A. I. Babutskii S. V. Kobel’skii I. V. Orynyak S. V. Romanov N. B. Trunov V. V. Denisov V. A. Piminov 《Strength of Materials》2007,39(5):539-544
Refined results of the stress-strain state evaluation for the hot header-steam generator connector weldment of small-and large-series
WWER-1000 reactors with three-dimensional models are presented. The layout of the steam generators in the reactors is shown
to influence maximum stresses in the vicinity of the weld.
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Translated from Problemy Prochnosti, No. 5, pp. 114–120, September–October, 2007. 相似文献
6.
Aditya M. Vora 《Journal of Superconductivity and Novel Magnetism》2007,20(5):355-368
The theoretical calculation of the superconducting state properties (SSP) viz electron–phonon coupling strength λ, Coulomb pseudopotential μ
*, transition temperature T
C
, isotope effect exponent α and effective interaction strength N
O
V of 50 binary metallic glasses of simple, non-simple, and transition metals have been carried out using a well-recognized
model potential. We have employed here five different types of local field correction functions proposed by Hartree (H), Taylor
(T), Ichimaru–Utsumi (IU), Farid et al. (F), and Sarkar et al. (S) to study the exchange and correlation effects on the present
investigations. Instead of using Vegard’s law, a pseudo-alloy-atom model (PAA) in the present investigation is proposed and
found successful. The present results of the SSP are found to be in qualitative agreement with other such earlier reported
data wherever they exist, which confirms the superconducting phase in the metallic glasses. 相似文献
7.
O. V. Suberlyak V. V. Krasins’kyi I. M. Shapoval O. M. Hrytsenko 《Materials Science》2011,46(5):669-678
We study the influence of concentrations of the components of reactive compositions and the conditions of production and hardening
of phenol-formaldehyde resins with the help of epoxy resins in the presence of polyvinylpyrrolidone on the physicomechanical,
thermal, adhesion, insulation, and anticorrosion properties of the composites. The positive effect of modifications with polyvinylpyrrolidone
and epoxy resin manifests itself within the following ranges of concentrations: 0.5–1 wt.% of polyvinylpyrrolidone and 25–30
wt.% of ED-20 in the presence of 1 wt.% of N, N-dimethylaniline. Thus, the adhesion strength of a glue based on the developed
composition becomes four times higher and constitutes 5–6 MPa; the impact strength, static strength in bending, surface hardness,
and the specific bulk electric resistance of the specimens hardened at 150–160°C for 25–30 min become 1.5–2.5 times higher
and are equal to 5–6J/m2, 15–17 MPa, 350–420 MPa, and (5.5–6.5)⋅1010 Ω⋅m, respectively. The behavior of these characteristics strongly depends on the conditions of hardening. We optimized the
composition of modified phenol-formaldehyde resins, which made it possible to produce materials with predicted properties. 相似文献
8.
9.
B. B. Straumal S. G. Protasova A. A. Mazilkin E. Rabkin D. Goll G. Schütz B. Baretzky R. Z. Valiev 《Journal of Materials Science》2012,47(1):360-367
The homogeneous coarse-grained (CG) Cu–Ni alloys with nickel concentrations of 9, 26, 42, and 77 wt% were produced from as-cast
ingots by homogenization at 850 °C followed by quenching. The subsequent high-pressure torsion (5 torsions at 5 GPa) leads
to the grain refinement (grain size about 100 nm) and to the decomposition of the supersaturated solid solution in the alloys
containing 42 and 77 wt% Ni. The lattice spacing of the fine Cu-rich regions in the Cu–77 wt% Ni alloy was measured by the
X-ray diffraction (XRD). They contain 28 ± 5 wt% Ni. The amount of the fine Ni-rich ferromagnetic regions in the paramagnetic
Cu–42 wt% Ni alloy was estimated by comparing its magnetization with that of fully ferromagnetic Cu–77 wt% Ni alloy. According
to the lever rule, these Ni-rich ferromagnetic regions contain about 88 wt% Ni. It means that the high-pressure torsion of
the supersaturated Cu–Ni solid solutions produces phases which correspond to the equilibrium solubility limit at 200 ± 40 °C
(Cu–77 wt% Ni alloy) and 270 ± 20 °C (Cu–42 wt% Ni alloy). To explain this phenomenon, the concept of the effective temperature
proposed by Martin (Phys Rev B 30:1424, 1984) for the irradiation-driven decomposition of supersaturated solid solutions was employed. It follows from this concept that
the deformation-driven decomposition of supersaturated Cu–Ni solid solutions proceeds at the mean effective temperature T
eff = 235 ± 30 °C. The elevated effective temperature for the high-pressure torsion-driven decomposition of a supersaturated
solid solution has been observed for the first time. Previously, only the T
eff equal to the room temperature was observed in the Al–Zn alloys. 相似文献
10.
11.
The life of high-strength materials under cyclic loading in the multiaxial stress state is experimentally estimated using
the deformation-kinetic criterion.
Translated from Problemy Prochnosti, No. 2, pp. 139–143, March–April, 2009. 相似文献
12.
B. S. Karpinos 《Strength of Materials》2009,41(3):268-277
We describe a procedure for representing material characteristics as thermodynamic invariants. It has enabled us to put forward
arguments of equations for limiting mechanical states under nonisothermal deformation for similar materials. The procedure
is based on relations of a simple theory of fracture and on the concepts of the similarity theory and dimensional analysis
theory.
Translated from Problemy Prochnosti, No. 3, pp. 45–57, May–June, 2009. 相似文献
13.
O. V. Veselov 《Measurement Techniques》2007,50(7):758-762
A method of estimating the actual state of electromechanical systems based on the use of a model, connected in parallel with
the diagnosed equipment, and an indirect measurement of the state variables is considered. A diagnostic system structure is
proposed and also versions of models which take the operating features into account.
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Translated from Izmeritel’naya Tekhnika, No. 7, pp. 43–46, July, 2007. 相似文献
14.
J. Ha S. Chae K. W. Chou T. Tyliszczak P. J. M. Monteiro 《Journal of Materials Science》2012,47(2):976-989
This study investigated the effects of organic polymers (polyethylene glycol and hexadecyltrimethylammonium) on structures
of calcium silicate hydrates (C–S–H) which is the major product of Portland cement hydration. Increased surface areas and
expansion of layers were observed for all organic polymer modified C–S–H. The results from attenuated total reflectance–Fourier
transform infrared (ATR–FTIR) spectroscopic measurements also suggest lowered water contents in the layered structures for
the C–S–H samples that are modified by organic polymers. Scanning transmission X-ray microscopy (STXM) results further supports
this observation. We also observed difference in the extent of C–S–H carbonation due to the presence of organic polymers.
No calcite formed in the presence of HDTMA whereas formation of calcite was observed with C–S–H sample modified with PEG.
We suggest that the difference in the carbonation reaction is possibly due to the ease of penetration and diffusion of the
CO2. This observation suggests that CO2 reaction strongly depends on the presence of organic polymers and the types of organic polymers incorporated within the C–S–H
structure. This is the first comprehensive study using STXM to quantitatively characterize the level of heterogeneity in cementitious
materials at high spatial and spectral resolutions. The results from BET, XRD, ATR–FTIR, and STXM measurements are consistent
and suggest that C–S–H layer structures are significantly modified due to the presence of organic polymers, and that the chemical
composition and structural differences among the organic polymers determine the extent of the changes in the C–S–H nanostructures
as well as the extent of carbonation reaction. 相似文献
15.
Several simple equations of state, requiring only two input properties, have been studied in order to determine the liquid
saturation density of 144 fluids of different kinds. This study includes old and new simple modifications of the van der Waals
equation of state, and the Carnahan–Starling–Yelash–Kraska and Carnahan–Starling–Dieterici equations. The new simple modifications
of the van der Waals equation give better overall results than some other more complex proposed equations, especially near
the critical point. The recent equation proposed by Eslami including the boiling temperature and density as input parameters
was also checked, and was found not to reproduce the critical point, but to give excellent results at intermediate or low
temperatures. As a reference, the behavior of the well-known Soave– Redlich–Kwong and Peng–Robinson equations, and the more
recent expression proposed by Mohsen-Nia et al. that requires three input parameters were also checked. The latter does not
improve the accuracy of the Peng–Robinson equation, and very simple van-der-Waals type equations give better overall results. 相似文献
16.
A stable correlation between the material fracture toughness characteristics and statistical parameters of scatter of hardness
values has been established.
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Translated from Problemy Prochnosti, No. 6, pp. 5–12, November–December, 2007. 相似文献
17.
The stress-strain state and the failure onset time are calculated by Rabotnov's kinetic theory of creep for a thick-walled
nonuniformly heated pipe loaded by internal pressure. We analyze the influence of the temperature difference along the pipe
radius on the stress intensity distribution and damageability parameter of material in the pipe cross section at various instants
of time up to the rupture onset. Based on the comparative analysis, we proved incompatibility of the results obtained by the
above-mentioned theory with those calculated by the similar theory of creep in the Kachanov's statement.
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Translated from Problemy Prochnosti, No. 5, pp. 30 – 44, September – October, 2005. 相似文献
18.
R. É. Minikes 《Measurement Techniques》2007,50(1):69-73
A method of obtaining the temperature corrections to readings of measuring instruments, taking their thermal inertia into
account, when the temperature of the medium changes is proposed. The procedure was tested under laboratory conditions on static
nonthermostated gravimeters. The results of the investigations, which confirm the effectiveness of the proposed procedure,
are presented.
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Translated from Izmeritel’naya Tekhnika, No. 1, pp. 50–52, January, 2007. 相似文献
19.
A. F. Nikitenko 《Strength of Materials》2005,37(6):551-557
For an arbitrary body (a structural member) subjected to external steady temperature and force actions, a limiting state condition
which ensures the uniform strength of the body until its load-carrying capacity is exhausted has been derived using Rabotnov's
kinetic theory of creep. A procedure of strength analysis of structural members by the limiting state is put forward. For
the case where the limiting state condition is fulfilled only on some individual portions of the body's surface, a procedure
of calculating its stress-strain state with the nearest approach to the uniform-strength state is outlined.
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Translated from Problemy Prochnosti, No. 6, pp. 5 – 14, November – December, 2005. 相似文献
20.
Models representing the thermodynamic behavior of the CO2–H2O mixture have been developed. The single-phase model is based upon the thermodynamic property mixture model proposed by Lemmon and Jacobsen. The model represents the single-phase vapor states over the temperature range of 323–1074 K, up to a pressure of 100 MPa over the entire composition range. The experimental data used to develop these formulations include pressure–density–temperature-composition, second virial coefficients, and excess enthalpy. A nonlinear regression algorithm was used to determine the various adjustable parameters of the model. The model can be used to compute density values of the mixture to within ±0.1%. Due to a lack of single-phase liquid data for the mixture, the Peng–Robinson equation of state (PREOS) was used to predict the vapor–liquid equilibrium (VLE) properties of the mixture. Comparisons of values computed from the Peng–Robinson VLE predictions using standard binary interaction parameters to experimental data are presented to verify the accuracy of this calculation. The VLE calculation is shown to be accurate to within ±3 K in temperature over a temperature range of 323–624 K up to 20 MPa. The accuracy from 20 to 100 MPa is ±3 K up to ±30 K in temperature, being worse for higher pressures. Bubble-point mole fractions can be determined within ±0.05 for CO2. 相似文献