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1.
S I Bondarenko A V Lukashenko A A Shablo E N Tilchenko Yu K Neimirok 《Bulletin of Materials Science》1991,14(4):1115-1118
The results of the study of dc interferometers and SQUIDS from the thick-film YBa1·5Ca0·5Cu3O7\t-\gd ceramics are presented here. It is shown that under the influence of high-density currents through the film constriction
the differential resistance of interferometers thus formed increases by 2–3 orders of magnitude and the voltage-field characteristics
become more regular. The frequency dependence of intrinsic noise in dc SQUIDs based on thick-film interferometers is investigated.
It is demonstrated that in the white noise frequency region (1–10 Hz) the energy sensitivity is withinδɛ
n
=10−28 to 10−29 J/Hz. 相似文献
2.
X-ray diffraction patterns of chemically deposited lead sulphide thin films have been recorded and X-ray line profile analysis
studies have been carried out. The lattice parameter, crystallite size, average internal stress and microstrain in the film
are calculated and correlated with molarities of the solutions. Both size and strain are found to contribute towards the broadening
of X-ray diffraction line. The values of the crystallite size are found to be within the range from 22–33 nm and the values
of strain to be within the range from 1·0 × 10−3–2·5 × 10−3. 相似文献
3.
N. Ramamanohar Reddy M. Venkata Ramana K. Krishnaveni K. V. Siva Kumar V. R. K. Murthy 《Bulletin of Materials Science》2007,30(4):357-363
Ferroelectromagnetic composites with compositions, X Ni0·5Zn0·5Fe1·95O4−δ
+ (1 − X) Ba0·8Pb0·2TiO3, in which X varies as 0, 0·005, 0·010, 0·015, 0·020, 0·040, 0·060, 0·080 and 1 in mole %, were prepared by conventional ceramic double
sintering process. The presence of two phases was confirmed by X-ray diffraction. The temperature variation of dielectric
constant, ɛ′, dielectric loss, tan δ, d.c. conductivity, a.c. conductivity, elastic and anelastic behaviour of ferrite-ferroelectric composites were studied in
the temperature range 30–350°C. The a.c. conductivity measurements on these composites in the frequency range 100 Hz-1 MHz
at room temperature reveal that the conduction mechanism is due to small polaron hopping. The dielectric and elastic data
were discussed in the light of phase transitions. 相似文献
4.
A large number of thin films of cadmium oxide have been prepared on glass substrates by spray pyrolysis method. The prepared
films have uniform thickness varying from 200–600 nm and good adherence to the glass substrate. A systematic study has been
made on the influence of thickness on resistivity, sheet resistance, carrier concentration and mobility of the films. The
resistivity, sheet resistance, carrier concentration and mobility values varied from 1·56–5·72×10−3 Ω-cm, 128–189 Ω/□, 1·6–3·9×1021 cm−3 and 0·3–3 cm2/Vs, respectively for varying film thicknesses. A systematic increase in mobility with grain size clearly indicates the reduction
of overall scattering of charge carriers at the grain boundaries. The large concentration of charge carriers and low mobility
values have been attributed to the presence of Cd as an impurity in CdO microcrystallites. Using the optical transmission
data, the band gap was estimated and found to vary from 2·20–2·42 eV. These films have transmittance around 77% and average
reflectance is below 2·6% in the spectral range 350–850 nm. The films aren-type and polycrystalline in nature. SEM micrographs of the CdO films were taken and the films exhibit clear grains and grain
boundary formation at a substrate temperature as low as 523 K. 相似文献
5.
B. P. Das R. N. P. Choudhary P. K. Mahapatra 《Journal of Materials Science: Materials in Electronics》2009,20(6):534-542
The Polycrystalline samples of (Pb1−x
Gd
x
)(Sn0.45Ti0.55)1−x/4O3 (PGST) (x = 0, 0.05, 0.07, 0.1) were prepared using a standard mixed-oxide method. The XRD and SEM studies of the samples reveal that
PGST samples have tetragonal symmetry with uniform grain distribution. Measurements of dielectric constant, dielectric loss
and ac electrical conductivity were made in a wide temperature (300–650 K) and frequency (100 Hz to 1 MHz) range. These materials
undergo a ferroelectric–paraelectric phase transition at 569, 582, 598, and 603 K for x = 0, 0.05, 0.07, 0.1, respectively. The ferroelectric property of some samples at room temperature was confirmed through
the study of hysteresis loops. The Cole–Cole plots (ε′′ vs. ε′) at 125 and 150 °C form semicircular arcs with the center lying
underneath the abscissa, deviated from the ideal Debye relaxation model to some extent. In all the compounds, the slope of
ln σac ~ 1/T shows a distinct variation for temperature below 450, 450 K to T
c and for T > T
c. The room temperature ac conductivity at 10 kHz lies in the range of 10−5–10−6 (Ω−1 m−1). 相似文献
6.
D. V. Dukhopel'nikov A. V. Zhukov D. V. Kirillov M. K. Marakhtanov 《Measurement Techniques》2005,48(10):995-999
High-speed video filming by the VS-FAST-NG CCD-array-based video camera from the firm of Videoskan with speeds of 1000 and
5000 frames per second and exposure time of 1·10−3 and 2·10−4 sec, respectively, is conducted. It is established that the arc burns from two or three cathode spots for (1–1.2)·10−3 sec. The mean and local speeds of the group of cathode spots are determined. If there is no external magnetic field present,
the mean speed is equal to 5–6 m/sec. If there is a magnetic field B = 0.005 T present, the mean speed is equal to 15–16 m/sec.
__________
Translated from Izmeritel'naya Tekhnika, No. 10, pp. 42–44, October, 2005. 相似文献
7.
S. Zainabidinov D. É. Nazirov A. Zh. Akbarov A. A. Iminov T. M. Toshtemirov 《Technical Physics Letters》1998,24(1):71-72
Diffusion of erbium in silicon has been investigated by the electric method. The erbium diffusion coefficient in the temperature
range 1150–1250 °C increases from 1.4×10−13 to 6.2×10− 13 cm2·s−1. The values obtained for the diffusion coefficient of erbium in silicon are in good agreement with data obtained by the method
of tagged atoms.
Pis’ma Zh. Tekh. Fiz. 24, 68–71 (January 26, 1998) 相似文献
8.
Magnetostriction actuators for superprecision positioning in steps of 10−2 nm over a range of displacements up to 1 m have been developed and investigated. The actuators generate forces up to 104 N and are suitable as power actuators in steps of 10 nm. Exact displacement is achieved by an active element made from Terfenol
D alloy based on rare-earth metals with a high magnetostriction. The actuators can be controlled manually without any additional
power source or by using a computer. For manual control the minimum linear-displacement step does not exceed 3 nm, and when
the device is used on a turntable the minimum linear displacement step is 15·10−3" while for computer control these quantities are 10−2 nm and 4·10−5", respectively.
Translated from Izmeritel'naya Tekhnika, No. 5, pp. 56–62, May, 1997. 相似文献
9.
ZnS thin films of different thicknesses were prepared by chemical bath deposition using thiourea and zinc acetate as S2− and Zn2+ source. The effect of film thickness on the optical and structural properties was studied. The optical absorption studies
in the wavelength range 250–750 nm show that band gap energy of ZnS increases from 3·68–4·10 eV as thickness varied from 332–76
nm. The structural estimation shows variation in grain size from 6·9–17·8 nm with thickness. The thermoemf measurement indicates
that films prepared by this method are of n-type. 相似文献
10.
New NASICON type materials of composition, Li3−2x
Al2−x
Sb
x
(PO4)3 (x = 0·6 to 1·4), have been prepared and characterized by powder XRD and IR. D.C. conductivities were measured in the temperature
range 300–573 K by a two-probe method. Impedance studies were carried out in the frequency region 102−106 Hz as a function of temperature (300–573 K). An Arrhenius behaviour is observed for all compositions by d.c. conductivity
and the Cole-Cole plots obtained from impedance data do not show any spikes on the lower frequency side indicating negligible
electrode effects. A maximum conductivity of 4·5 × 10−6 S cm−1 at 573 K was obtained for x = 0·8 of the Li3−2x
Al2−x
Sb
x
(PO4)3 system. 相似文献
11.
Transparent and conducting SnO2 films are prepared at 500°C on quartz substrates by chemical vapour deposition technique, involving oxidation of SnCl2. The effect of oxygen gas flow rate on the properties of SnO2 films is reported. Oxygen with a flow rate from 0·8–1·35 lmin−1 was used as both carrier and oxidizing gas. Electrical and optical properties are studied for 150 nm thick films. The films
obtained have a resistivity between 1·72 × 10−3 and 4·95 × 10−3 ohm cm and the average transmission in the visible region ranges 86–90%. The performance of these films was checked and the
maximum figure of merit value of 2·03 × 10−3 ohm−1 was obtained with the films deposited at the flow rate of 1·16 lmin−1. 相似文献
12.
Ju-Yeon Lee Jin-Hyang Kim Won-Taek Jung Young Kum Park 《Journal of Materials Science》2007,42(11):3936-3943
2,3-Di-(2′-hydroxyethoxy)benzylidenemalononitrile (3) was prepared and condensed with 2,4-toluenediisocyanate and 3,3′-dimethoxy-4,4′-biphenylenediisocyanate to yield novel Y-type
polyurethanes 4–5 containing 2,3-dioxy benzylidenemalononitrile group as a nonlinear optical (NLO)-chromophore, which constituted parts of
the polymer backbones. Polyurethanes 4–5 were soluble in common organic solvents such as acetone and N,N-dimethylformamide. They showed a thermal stability up to 270 °C in thermogravimetric analysis thermograms and the glass-transition
temperatures (T
g) obtained from differential scanning calorimetry thermograms were around 116–135 °C. The second harmonic generation (SHG)
coefficients (d
33) of poled polymer films at 106.4 mm−1 fundamental wavelength were around 9.07 × 10−19 C (2.72 × 10−9 esu). The dipole alignment exhibited high thermal stability up to 10 °C higher than T
g, and there was no SHG decay below 145 °C due to the partial main-chain character of the polymer structure, which was acceptable
for nonlinear optical device applications. 相似文献
13.
K. H. Kang H. S. Moon K. C. Song M. S. Yang S. H. Lee S. W. Kim 《International Journal of Thermophysics》2007,28(5):1595-1606
The thermal diffusivity of a simulated fuel with fission products forming a solid solution was measured using the laser-flash
method in the temperature range from room temperature to 1673 K. The density and the grain size of the simulated fuel with
the solid solutions used in the measurement were 10.49 g · cm−3 (96.9% of theoretical density) at room temperature and 9.5 μm, respectively. The diameter and thickness of the specimens were 10 and 1 mm, respectively. The thermal diffusivity decreased
from 2.108 m2 · s−1 at room temperature to 0.626 m2 · s−1 at 1673 K. The thermal conductivity was calculated by combining the thermal diffusivity with the specific heat and density.
The thermal conductivity of the simulated fuel with the dissolved fission products decreased from 4.973 W · m−1 · K−1 at 300 K to 2.02 W · m−1 · K−1 at 1673 K. The thermal conductivity of the simulated fuel was lower than that of UO2 by 34.36% at 300 K and by 15.05% at 1673 K. The difference in the thermal conductivity between the simulated fuel and UO2 was large at room temperature, and decreased with an increase in temperature.
Paper presented at the Seventeenth European Conference on Thermophysical Properties, September 5–8, 2005, Bratislava, Slovak
Republic. 相似文献
14.
The oxidation behaviour of Zr-based bulk amorphous alloy Zr65Cu17.5Ni10Al7.5 has been studied in air environment at various temperatures in the temperature range 591–684 K using a thermogravimetric
analyser (TGA). The oxidation kinetics of the alloy in the amorphous phase obeys the parabolic rate law for oxidation in the temperature
range 591–664 K. The values of the activation energy and pre-factor as calculated from the Arrhenius temperature dependence
of the rate constants have been found to be 1.80 eV and 2.12 × 109 g·cm−2·sec−1/2, respectively. 相似文献
15.
Yogesh Sharma N. Sharma G. V. Subba Rao B. V. R. Chowdari 《Bulletin of Materials Science》2009,32(3):295-304
Cadmium ferrite, CdFe2O4, is synthesized by urea combustion method followed by calcination at 900°C and characterized by X-ray diffraction (XRD),
scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HR-TEM) and selected area electron diffraction
(SAED) techniques. The Li-storage and cycling behaviour are examined by galvanostatic cycling, cyclic voltammetry (CV) and
impedance spectroscopy in the voltage range, 0·005–3·0 V vs Li at room temperature. CdFe2O4 shows a first cycle reversible capacity of 870 (± 10) mAhg−1 at 0·07C-rate, but the capacity degrades at 4 mAhg−1 per cycle and retains only 680 (± 10) mAhg−1 after 50 cycles. Heat-treated electrode of CdFe2O4 (300°C; 12 h, Ar) shows a significantly improved cycling performance under the above cycling conditions and a stable capacity
of 810 (± 10) mAhg−1 corresponding to 8·7 moles of Li per mole of CdFe2O4 (vs theoretical, 9·0 moles of Li) is maintained up to 60 cycles, with a coulombic efficiency, 96–98%. Rate capability of
heat-treated CdFe2O4 is also good: reversible capacities of 650 (± 10) and 450 (± 10) mAhg−1 at 0·5 C and 1·4 C (1 C = 840 mAg−1) are observed, respectively. The reasons for the improved cycling performance are discussed. From the CV data in 2–15 cycles,
the average discharge potential is measured to be ∼0·9 V, whereas the charge potential is ∼2·1 V. Based on the galvanostatic
and CV data, ex situ-XRD, -TEM and -SAED studies, a reaction mechanism is proposed. The impedance parameters as a function of voltage during the
1st cycle have been evaluated and interpreted.
Dedicated to Prof. C N R Rao on his 75th birthday, and his contributions to science for the past 56 years 相似文献
16.
Flexible piezo- and pyroelectric composite was made in the thin film form by spin coating. Lead Zirconate Titanate (PZT) ceramic
powder was dispersed in a castor oil-based polyurethane (PU) matrix, providing a composite with 0–3 connectivity. The dielectric
data, measured over a wide range of frequency (10–5 Hz to 105 Hz), shows a loss peak around 100 Hz related with impurities in the polymer matrix. There is also an evidence of a peak in
the range 10–4 Hz, possibly originating from the glass transition temperature Tg of the polymer. The pyroelectric coefficient at 343 K is 7.0×10–5 C·m–2·K–1 which is higher than that of β-PVDF (1×10–5 C·m–2·K–1).
Electronic Publication 相似文献
17.
V. I. Kyryliv 《Materials Science》1998,34(3):416-419
It is shown that intense saturation of the surface layers of a hardened metal with nickel, copper, and chromium from electroplates
occurs in the course of mechanical pulse treatment in the zone of frictional contact. In this case, the mass transfer coefficients
range from 0.95·10−7 to 1.1·10−7 m2/sec. It is established that the number of alloying elements is defined by the number of generated dislocations.
Karpenko Physicomechanical Institute, Ukrainian Academy of Sciences, L'viv. Translated from Fizyko-Khimichna Mekhanika Materialiv,
Vol. 34, No. 3, pp. 108–110, May–June, 1998. 相似文献
18.
V. A. Lyubochko V. V. Malikov O. G. Parfenov N. V. Belousova 《Journal of Engineering Physics and Thermophysics》2000,73(3):568-572
A new method is proposed and experimental investigations are carried out aimed at reducing aluminum oxide in a nonequilibrium
hydrogen plasma of a combined glow discharge (CGD) at a pressure of 1315.8–13,158 Pa, a discharge current of 5·10−2–3 A, and a hydrogen flow rate of 10−6–10−4 nm3/sec. A high degree of conversion of the aluminum oxide (60%) with an energy consumption of 20 kW·h/kg of Al2O3 is attained. Reduction of metals from oxides and other compounds in a CGD nonequilibrium hydrogen plasma can be used for
producing rare-earth and high-purity metals.
Translated from Inzhenerno-Fizcheskii Zhurnal, Vol. 73, No. 3, pp. 580–584, May–June, 2000. 相似文献
19.
Pushpa Muthiah K. S. Seshadri P. K. Sinha K. B. Lal 《Bulletin of Materials Science》2007,30(5):521-526
Study on the cementation of the regenerated activity (from spent resin using ferric as regenerant) containing ferric in cement
matrix showed that compressive strength and leaching behaviour are better when the ferric strength was < 5 N. The diffusion
coefficient of Cs from the cement matrix was found to be in the range 2.4 × 10−5 cm2/day and 5.9 × 10−5 cm2/day with ferric solutions of strength in the range 0.5–3 N. When bentonite and vermiculite were included in the cement matrix,
the diffusion coefficient of Cs was found to be in the range 6.2 × 10−7 cm2/day to 1.26 × 10−5 cm2/day with ferric strength in the same range. 相似文献
20.
The DC electrical resistivity results of La4 −x
Sr1 +x
Cu5 −x
Fe
x
O12 + δ (0 ≤x ≤ 1·0) showed that for S1 (x = 0) and S2 (x = 0·25) the temperature coefficient of resistivity (TCR), dρ/dT, is positive and slightly increases with increasing temperature in the range 20–270 K. This shows the metallic nature of
S1 and S2. For the samples S3(x = 0·5) and S4 (x = 0·75), TCR slightly increases in the range 20–270 K, with change in sign from negative to positive at ∼ 80 K and ∼ 130
K, respectively. These results show the metal-insulator type transition in S3 and S4. For the sample S5 (x = 1·0), the TCR is negative and gradually increases in the range 20–270 K, which shows its semiconductor-like behaviour.
The activation energy for S5 is found to be 0·21 × 10−2 eV. Furthermore, the DC resistivity results of S1–S5 in the range 350–660 K are in conformity with the low temperature results.
The very weak temperature dependence of magnetic susceptibility results of S1–S3 show Pauli-paramagnetic behaviour in the
range 77K–400 K, while S4 and S5 exhibit Pauli-paramagnetic behaviour in the range 77–850 K. Long-range antiferromagnetic
interaction is observed in S5 (x = 1·0) belowT
c ∼ 100 K. The room temperature EPR lineshapes gradually improve from metallic S1 (x = 0) to semiconductor-like S5(x = 1·0). Negativeg-shift is observed in the samples S2–S5 with increasing trend ing
iso-values of 1·880 in S2 to 1·961 in S5. However, theg
iso-value for S1 could not be observed due to very poor lineshape. 相似文献