共查询到20条相似文献,搜索用时 46 毫秒
1.
V. R. Shayapov M. L. Kosinova A. P. Smirnov E. A. Maksimovskii B. M. Ayupov Yu. M. Rumyantsev 《Inorganic Materials》2011,47(3):262-266
Boron carbonitride (BC
x
N
y
) films of different compositions have been grown by low-pressure chemical vapor deposition using triethylamine borane as
a single-source precursor and ammonia as an additional nitrogen source. Experiments were performed at various initial vapor
compositions. The resultant films have been characterized by ellipsometry, IR spectroscopy, energy dispersive X-ray spectroscopy,
scanning electron microscopy, nanoindentation, and surface acoustic wave spectroscopy. The mechanical properties of the films
are shown to correlate with their density and chemical composition. With increasing initial ammonia partial pressure in the
vapor phase, the elemental composition of the films moves away from boron carbide, approaching boron nitride, which is accompanied
by a reduction in the Young’s modulus, hardness, and density of the films. 相似文献
2.
3.
This paper reports the results of photoacoustic measurements of Cd1-xBexSe mixed crystals grown by the high pressure Bridgman method with varying concentrations of Be (0.1 < x < 0.2). For examining continuous wave photoacoustic spectra, a piezoelectric transducer (PZT) and an open cell were used. An increase of the energy gap with increasing x has been observed. The thermal diffusivity values were estimated using the dependence of the amplitude and phase of the PA signal on the light modulation frequency.Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A. 相似文献
4.
We have studied the influence of irradiation by 4-MeV electrons via flat metal screens on the main electrical characteristics
of high-power silicon diodes intended to operate at currents up to 600 A. The electron irradiation was performed via metal
masks, which led to the formation of enhanced recombination zones (ERZs) in the base region of p
+-n-n
+ silicon structures. It is shown that the local irradiation of a large-area diode structure improves (as compared to the total
irradiation) the relationship been the reverse recovery time (t
rr
) and energy loss in the conducting state (U
f
), while decreasing the temperature sensitivity of the reverse current (I
R
). It is established that the relationships between t
rr
, U
F
, and I
R
in locally irradiated structures depends on the experimental conditions (ERZ size). 相似文献
5.
Ion Lizarraga M. Mounir Bou-Ali C. Santamaría 《Microgravity science and technology》2018,30(5):591-598
In this study, the thermodiffusion coefficient of n-dodecane/n-hexane binary mixture at 25 °C mean temperature was determined for several pressure conditions and mass fractions. The experimental technique used to determine the thermodiffusion coefficient was the thermograviational column of cylindrical configuration. In turn, thermophysical properties, such as density, thermal expansion, mass expansion and dynamic viscosity up to 10 MPa were also determined. The results obtained in this work showed a linear relation between the thermophysical properties and the pressure. Thermodiffusion coefficient values confirm a linear effect when the pressure increases. Additionally, a new correlation based on the thermodiffusion coefficient for n C12/n C6 binary mixture at 25 °C temperature for any mass fraction and pressures, which reproduces the data within the experimental error, was proposed. 相似文献
6.
T. S. Khasanshin V. S. Samuilov A. P. Shchemelev 《Journal of Engineering Physics and Thermophysics》2008,81(4):760-765
This paper describes an improved experimental facility for measuring the speed of sound in liquids with an accuracy of up
to 0.1%. Measurements of the speed of sound in liquid n-hexane, n-octane, n-decane, and n-hexadecane at temperatures of 298–433
K and pressures of 0.1–100 MPa have been made. It has been shown that in the possible comparison range the obtained values
of the speed of sound are in good agreement with the literature data.
Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 81, No. 4, pp. 732–736, July–August, 2008. 相似文献
7.
D. L. Tsyganov 《High Temperature》2016,54(1):68-77
The numerical-analytical investigation of the shock forced oscillator (SFO) model is complete. Approaches for calculating the probabilities of quantum transitions from the initial to some final state with VV energy exchange of diatomic molecules and VV and VT energy exchange of polyatomic molecules are considered. Formulas for calculating the probabilities of the \({W_{{i_1},{i_2} \to {f_1},{f_2}}}\) transition for VV energy exchange in collision of molecules AB and CD within the harmonic approximation are represented (SFHO model). It is shown that the probabilities of a quantum transition in VV and VT energy exchange of polyatomic molecules can be calculated in terms of the quantum transition probability for VT energy exchange of diatomic molecules on the assumption of “frozen” quantum transitions of polyatomic molecules. The problem of determining the dissociation rate constant is considered by the example of a nitrogen molecule (N2) in the N2–N2 system for the “improved” Lennard-Jones potential in VV energy exchange. The calculated dissociation rate constant is compared with the experimental data obtained for a shock tube. 相似文献
8.
Mehdi Razavi Mohammadhossein Fathi Omid Savabi Lobat Tayebi Daryoosh Vashaee 《Journal of materials science. Materials in medicine》2018,29(10):159
Magnesium (Mg) alloys as a new group of biodegradable metal implants are being extensively investigated as a promising selection for biomaterials applications due to their apt mechanical and biological performance. However, as a foremost drawback of Mg alloys, the high degradation in body fluid prevents its clinical applications. In this work, a bioceramic composite coating is developed composed of diopside, bredigite, and fluoridated hydroxyapatite on the AZ91 Mg alloy in order to moderate the degradation rate, while improving its bioactivity, cell compatibility, and mechanical integrity. Microstructural studies were performed using a transmission electron microscope (TEM), scanning electron microscope (SEM), X-ray diffraction (XRD) analysis, and energy dispersive spectroscopy (EDS). The degradation properties of samples were carried out under two steps, including electrochemical corrosion test and immersion test in simulated body fluid (SBF). Additionally, compression test was performed to evaluate the mechanical integrity of the specimens. L-929 fibroblast cells were cultured on the samples to determine the cell compatibility of the samples, including the cell viability and attachment. The degradation results suggest that the composite coating decreases the degradation and improves the bioactivity of AZ91 Mg alloy substrate. No considerable deterioration in the compression strength was observed for the coated samples compared to the uncoated sample after 4 weeks immersion. Cytotoxicity test indicated that the coatings improve the cell compatibility of AZ91 alloy for L-929 cells. 相似文献
9.
S. L. Liu 《Journal of Superconductivity and Novel Magnetism》2008,21(3):199-203
Based on the Arrhenius equation, a method to calculate the activation energy from the resistance transition is proposed for
high temperature superconductors. This method is applied to the Y-based superconductors. The activation energy is found to
be U(T,H)∼(1−T/T
c
)4.8(H/H
0)−3.8 of YBCO crystal, and U(T,H)∼(1−T/T
c
)3.3(H/H
0)−2.2 of Er doped MTG YBCO crystal, respectively. With the obtained activation energy U(T,H), the lower part of the experimental curve ρ(T,H) and its derivative can be reproduced.
相似文献
10.
Rodríguez-Hernández AG Juárez A Engel E Gil FJ 《Journal of materials science. Materials in medicine》2011,22(8):1913-1922
Dental implant failure is commonly associated to dental plaque formation. This problem starts with bacterial colonization
on implant surface upon implantation. Early colonizers (such as Streptococcus sanguinis) play a key role on that process, because they attach directly to the surface and facilitate adhesion of later colonizers.
Surface treatments have been focused to improve osseointegration, where shot-blasting is one of the most used. However the
effects on bacterial adhesion on that sort of surfaces have not been elucidated at all. A methodological procedure to test
bacterial adherence to titanium shot-blasted surfaces (alumina and silicon carbide) by quantifying bacterial detached cells
per area unit, was performed. In parallel, the surface properties of samples (i.e., roughness and surface energy), were analyzed
in order to assess the relationship between surface treatment and bacterial adhesion. Rather than roughness, surface energy
correlated to physicochemical properties of shot-blasted particles appears as critical factors for S. sanguinis adherence to titanium surfaces. 相似文献
11.
The binding energies of Si 2p and Co 3p core-shell electrons in four stable cobalt silicides (Co3Si, Co2Si, CoSi, and CoSi2) have been determined by high-resolution photoelectron spectroscopy using synchrotron radiation. The silicides were formed
by solid-state epitaxy under identical conditions on Si(100), Si(110), and Si(111) faces of silicon single crystals. 相似文献
12.
R. Velazquez-Hernandez I. Rojas-Rodriguez J. Carmona-Rodríguez S. Jiménez-Sandoval M. E. Rodriguez-Garcia 《International Journal of Thermophysics》2011,32(3):720-728
In this research quaternary alloy thin films made of Cu, CdTe, and O have been grown and characterized. The samples used in
this investigation were grown simultaneously by reactive RF co-sputtering and by introducing oxygen and argon in the chamber
during growth and changing the power in the Cu target from 10 W to 50 W. The carrier distribution as a function of the position
was studied by using energy dispersive spectroscopy–scanning electronic microscopy (EDS–SEM), micro-Raman spectroscopy, and
photocarrier images. Structural characterization was carried out by using X-ray diffraction. According to the results, a lateral
carrier distribution was found in all samples and a new phase identified as Cu2Te was revealed for samples grown at 50 W. 相似文献
13.
The dynamic properties of the triangular Ising ferromagnet consisting of the mixed spins A = 1/2, B = 1/2, and C = 1 is studied by using the mean-field theory (MFT) as well as Glauber-type stochastic dynamics (GSD). The coupling equations to investigate dynamic behaviors of the system are calculated, and phase transitions, phase diagrams, and hysteresis curves are obtained. From these studies, first- and second-order transition lines, the dynamic phase diagrams (DPDs) in the (T,h 0) and (T,d) planes, and single hysteresis curves are presented. In the DPDs, dynamic tricritical point due to the first- and second-order phase transitions are observed. It is found that the dynamic hysteresis properties of the triangular system strongly depend on the temperature and crystal field. 相似文献
14.
T. S. Khasanshin V. S. Samuilov A. P. Shchemelev F. M. Mosbach 《Journal of Engineering Physics and Thermophysics》2010,83(5):1043-1053
By the method of direct measurement of the pulse-passage time, the velocity of sound in a binary liquid mixture n-dodecane+n-hexadecane has been investigated in the temperature range 298–433 K and in the pressure range 0.1–100.1 MPa. The maximum
measurement error is 0.1%. Experimental data on the velocity of sound for the investigated mixture have been obtained for
the first time. On the basis of the data on the velocity of sound, we have determined the density, the isobaric expansion
coefficient, the isobaric and isochoric heat capacities, and the isothermal compressibility coefficient of a mixture of three
compositions in the 298–433 K temperature range and in the 0.1–100.1 MPa range of pressures. The coefficients of the Tate
equations in the above range of parameters have been calculated. A table of thermodynamic properties of the mixture is presented. 相似文献
15.
n-Si/n-Cd1 - x
ZnxS heterojunctions are produced by electrodepositing Cd1 - x
ZnxS (0 x 0.6) films on silicon substrates, and their electrical and photoelectric properties are studied. The results demonstrate that the spectral response of the heterojunctions depends strongly on the film composition and heat-treatment conditions. The highest photosensitivity is achieved at x = 0.6 by heat treatment at 350°C for 7 min: V
OC = 0.5 V and I
SC = 3.8 mA/cm2 under illumination of 1500 lx at 300 K.Translated from Neorganicheskie Materialy, Vol. 41, No. 3, 2005, pp. 276–280.Original Russian Text Copyright © 2005 by Mamedov, Gasanov, Amirova.This revised version was published online in April 2005 with a corrected cover date.This revised version was published online in April 2005 with a corrected cover date. 相似文献
16.
The influence of treatment by a low energy hydrogen ions on degradation of the spectral response, diffusion length of minority carriers (LD) and efficiency (η) of silicon p-n junction photodiodes (solar cells without antireflective coatings) under the effect of electron irradiation has been investigated. Evaluation of the radiation hardness was made by subjecting the unhydrogenated and hydrogenated photodiodes to 1 MeV electron irradiation with doses of (0.1÷3) × 1015 cm-2. The measurements have shown that pre-hydrogenation of the silicon p-n junction devices significantly decreases the degradation rate of LD and η thereby improving their radiation hardness. 相似文献
17.
E. A. Baranov A. O. Zamchii A. I. Safonov S. V. Starinskii S. Ya. Khmel’ 《Technical Physics Letters》2017,43(3):244-246
Data on the optical properties of a nanocomposite material constituted by gold nanoparticles covered with a thin film of amorphous hydrogenated silicon suboxide have been obtained for the first time. The thin film was deposited by gas-jet electron-beam plasma chemical-vapor deposition. As gold particles situated on the surface of quartz glass are covered with a thin a-SiO x : H film, their plasmonic resonance peak is shifted to longer wavelengths. The calculations made in the study demonstrated a good agreement with the experiment. 相似文献
18.
A. N. Golubenko M. L. Kosinova V. S. Sulyaeva Yu. M. Rumyantsev N. I. Fainer F. A. Kuznetsov 《Inorganic Materials》2009,45(12):1342-1345
Thermodynamic modeling of the chemical vapor deposition of boron-carbonitride-based films in the B-C-N-H-O system using mixtures of N-trimethylborazine and nitrogen is carried out for reduced pressures (13.3 and 1.33 Pa) and a wide temperature range (300–1300 K). The source of oxygen impurities in this system is a residual pressure of 0.40 Pa. The results indicate that films of various compositions can be grown. The conditions for the deposition of BC x N y films are identified. 相似文献
19.
The time-dependent Ginzburg–Landau equation with thermal noise is used to calculate the Nernst signal e
N
, describing the Nernst effect, in type-II superconductor in the vortex-liquid regime. The Gaussian method used is an elaboration
of the Hartree–Fock method. An additional assumption often made in analytical calculations that only the lowest Landau level
significantly contributes to physical quantities of interest in the high-field limit is lifted by including all the Landau
levels. The values of e
N
are in good quantitative agreement with experimental data for temperature close to T
c
on Bi2Sr2CaCu2O8+δ
and Bi2Sr2Ca2Cu3O10+δ
. 相似文献
20.
Weiyan Wang Deren Yang Xuegong Yu Duanlin Que 《Journal of Materials Science: Materials in Electronics》2008,19(1):32-35
The effect of point defects on the recombination activity of copper (Cu) precipitates in p-type Czochralski (CZ) silicon has been investigated by means of microwave photoconductivity decay and electron beam induced current (EBIC). It was found that the value of the reciprocal of effective minority carrier lifetime and EBIC contrast of the samples with pre-annealing in Ar, without pre-annealing and with pre-annealing in O2, related to the recombination activity of Cu precipitates, decreased in turn. It was considered that the highest recombination activity of Cu precipitates in the sample with pre-annealing in Ar was mainly attributed to the relative higher minority carrier capture cross section of Cu precipitates, which was affected by the induced vacancies. While the weakest recombination activity of Cu precipitates in the sample with pre-annealing in O2 was ascribed to the relative lower density of Cu precipitates, which was influenced by the induced silicon interstitials. 相似文献