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1.
Carbon nanotubes (CNTs) were vertically well-grown on Ni/Cr-deposited glass substrates at 580 °C by ICPCVD and bias-assisted ICPHFCVD techniques. The vertically well-aligned CNTs showed multi-walled type with hollow structure. The measured critical current density on CNTs grown by the ICPCVD technique was 1.0×10–6 A cm–2 at 5 V m–1 of turn-on field and 7.7×10–5 A cm–2 at 7.8 V m–1 of the critical field. On the other hand, the critical current density on CNTs grown by the bias-assisted ICPHFCVD technique was 3.7×10–7 A cm–2 at 3 V m of turn-on field and 3.3×10–4 A cm–2 at 6.8 V m–1 of the critical field, respectively. On comparing the two processes, it can be concluded that CNTs grown by bias-assisted ICPHFCVD are more suitable than those grown by ICPCVD for the possible application of field emission displays (FEDs).  相似文献   

2.
This paper presents a technique for the preparation of vertically grown carbon nanotubes (CNTs) by bias-assisted inductively coupled plasma hot-filament chemical vapor deposition. Purification of the CNTs using r.f. plasma in a one-step process, based on the different etching property of the metal tip is also discussed. The Ni at the tip of the CNTs was effectively removed by using r.f. plasma based on the different etching property. After purification CNTs show the multi-walled and hollow-type structure. The measured critical current density on CNTs with a Ni tip was 3.52×10–7 A cm–2 at 2.47 V m–1 turn-on field and 6.6×10–4 A cm–2 at 4.8 V m–1 of the critical field. On the other hand, the critical current density on purified CNTs after Ni removal by an r.f. source was 1.36×10–7 A cm–2 at 2.1 V m–1 turn-on field and 1.5×10–3 A cm–2 at 6 V m–1 of the critical field, respectively.  相似文献   

3.
Results are given of an experimental investigation of the behavior of a vapor film on a highly superheated hemispherical surface immersed in water subcooled to the saturation temperature. The conditions of existence of vapor films on a hot surface and the characteristics of their collapse from the heating surface and transition to nucleate boiling are revealed, as well as the effects which accompany the vanishing of vapor film. The possibilities of internal triggering of fine fragmentation of hot melt and vapor explosion are discussed.Translated from Teplofizika Vysokikh Temperatur, Vol. 43, No. 1, 2005, pp. 100–114.Original Russian Text Copyright © 2005 by V. S. Grigorev, V. G. Zhilin, Yu. A. Zeigarnik, Yu. P. Ivochkin, V. V. Glazkov, and O. A. Sinkevich.  相似文献   

4.
A porous-coated Ti-6Al-4V implant was fabricated by electrical resistance sintering, using 480 F capacitance and 1.5 kJ input energy. X-ray photoelectron spectroscopy (XPS) was used to study the surface characteristics of the implant material before and after sintering. There were substantial differences in the content of O and N between as-received atomized Ti-6Al-4V powders and the sintered prototype implant, which indicates that electrical resistance sintering alters the surface composition of Ti-6Al-4V. Whereas the surface of atomized Ti-6Al-4V powders was primarily TiO2, the surface of the implant consisted of a complex of titanium oxides as well as small amounts of titanium carbide and nitride. It is proposed that the electrical resistance sintering process consists of five stages: stage I – electronic breakdown of oxide film and heat accumulation at the metal-oxide interface; stage II – physical breakdown of oxide film; stage III – neck formation and neck growth; stage IV – oxidation, nitriding, and carburizing; and stage V – heat dissipation. The fourth stage, during which the alloy repassivates, is responsible for the altered surface composition of the implant.  相似文献   

5.
Summary Measurements have been made on the electrochemical parameters in a model corrosion gap as affected by tensile stresses varying from zero up to the yield point of the material. It is shown on various constructional materials (D16T aluminum alloy, steel 45, Kh18N12T steel, and PT-3V titanium alloy) that the passivation time for a freshly renewed surface is reduced by a factor 1.5–3.5 as increases, while the galvanic current increases by a factor 1.2–3.0 and the electrode potentials shift by 30–100 mV in accordance with the pH. Numerical values are given for the parameters as functions of and pH.Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 26, No. 4, pp. 22–25, July–August, 1990.  相似文献   

6.
A comparison standard is developed in the form of a small voltage standard based on the Josephson effect whose metrological characteristics make it possible to compare stationary voltage standards with uncertainty less than 10–9. The standard was used in key comparisons of national voltage standards within the framework of Euromet Project N 723.__________Translated from Izmeritelnaya Tekhnika, No. 2, pp. 48–51, February, 2005.  相似文献   

7.
An experimental investigation is performed of the electrical and spectral characteristics of plasma of an electrodeless neon light source operating on the principle of inductively coupled discharge. The investigations are performed under the optimal conditions of discharge burning (neon pressure of 1 torr, current frequency of 250 kHz, and discharge current of 3 to 10 A) corresponding to the high efficiency of the light source (20%). The spatial distribution of the radiation intensity of individual lines of neon is studied. Measurements are performed of discharge spectra at different points of the gas-discharge bulb and of the electrical characteristics of the discharge. The resultant experimental data are used to calculate and analyze the parameters of discharge plasma (the electron density and temperature and the concentration of excited atoms).__________Translated from Teplofizika Vysokikh Temperatur, Vol. 43, No. 2, 2005, pp. 181–187.Original Russian Text Copyright © 2005 by M. V. Isupov, and I. M. Ulanov.  相似文献   

8.
A new procedure of determination of the effective density of the current in a nonstationary arc spot with the use of thermophysical and spectroscopic measurements has been proposed and tested. The procedure is based on recording of the critical cathode temperature corresponding to the instant of sharp increase in the intensity of the CuI = 5218 Å atomic spectral line, which coincides with the beginning of intense emission of a copper vapor from the spot, according the hypothesis proposed. New results are compared to those obtained earlier by purely thermophysical methods.__________Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 78, No. 1, pp. 159–166, January–February, 2005.  相似文献   

9.
Granular composite samples of GdBa2Cu3O7– (Gd123), PrBa2Cu3O7– (Pr123), and Pr0.5Ba0.5Ba2Cu3O7– (PrBa123) have been prepared by the solid state reaction technique. The characterization of samples has been done by SEM and XRD measurements. We have investigated the effect of Pr123 and PrBa123 insulating grains on the superconductor-insulator transition and the normal state resistivity of the (1–n)Gd123-nPr123 and (1–m)Gd123-mPrBa123 systems. The dominant diffusion of Pr ions onto the neighboring Gd123 grains in (1–n)Gd123-nPr123 causes high rate of suppression of superconductivity similar to the chemical-doped GdPr123 system. For (1–m)Gd123-mPrBa123 system, the suppression rate is slower and we have superconducting sample with Tcmid = 41 K for the second phase of m = 0.6 sample. Comparison of the superconductor-insulator and metal-insulator transitions in the granular samples and the chemical substituted GdPr123 indicates optimization of the superconducting state in (1–n)Gd123-mPrBa123 relative to (1–n)Gd123-nPr123 and GdPr123 systems. The more stable characteristic of PrBa123 relative to Pr123, when they are mixed with Gd123 grains, makes PrBa123 more suitable for any superconductor-insulator application. The mechanism of suppression of superconducting state for Pr123 has been discussed by comparison of experimental results against the hole filling and hole localization models presented for the insulating Pr123.  相似文献   

10.
Results are given for the reconstruction, based on spectral distributions of the amplification factor of the active medium, of the progressive temperature and the upper laser level temperature in the working chamber of a 1.2-kV technological CO2 laser. The obtained data on the temperature distribution in the zone of excitation of the medium enabled us to formulate requirements on organizing the process of laser energy removal and to assess the efficiency of the resonator devices used.Academic Scientific Complex A. V. Luikov Institute of Heat and Mass Transfer, Minsk. Institute of Flow Machines, Academy of Sciences of Poland, Gdansk. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 67, Nos. 3–4, pp. 281–286, September–October, 1994.  相似文献   

11.
Sodium diborate glasses (Na2B4O7) doped with 0.5 mol % Fe, Cu and V were irradiated by -rays at room temperature at a dose rate of 175 Gyh–1 for 8 and 30 h. The spectral absorption of these glasses before and after irradiation was measured in the range 185–2500 nm and was compared with that of the base glass (Na2B4O7). The spectral measurements were used to explore the effect of Fe, Cu and V in low quantities on the formation of colour centres in the base glass and, in particular, the sensitivity of these glasses to low and high doses of -rays.  相似文献   

12.
Electroless deposition of Ni–Zn–P layers was studied on steel electrodes by varying the bath temperature (40–90°C), pH and chemical composition. The deposition parameters were optimized. Alloys containing 70–86 wt % Ni, 6–20 wt % Zn and 6–10 wt % P are obtained at 20 m h–1 and 85°C. Corrosion measurements were performed in aerated 5% sodium chloride solution, the corrosion potential and current density are, respectively, –0.49 V/SCE and 2.6 A cm–2.  相似文献   

13.
The spectrum of dielectronic satellites of resonance lines of the neon-like selenium ion was analyzed experimentally and theoretically. The satellite line spectrum resulting from stabilizing radiative transitions from doubly excited states of the sodium-like selenium ion to nonautoionizing states was obtained using a laser plasma and a record spectral resolution of / 5000–8000. A detailed analysis is given of the laser plasma x-ray emission spectrum in the range 7.2–8.8 Å, more than 300 lines or compact groups of spectral lines were identified, and their wavelengths were measured with an error of ±5–10 –4 Å.The good agreement between the modeled and experimental spectra indicates that the emission spectrum of Na-like ions shows promise for use in high-temperature plasma diagnostics.Translated from Izmeritel'naya Tekhnika, No. 5, pp. 3–15, May, 1994.  相似文献   

14.
The lattice parameters and composition range of orthorhombic CaTi1 – x CrxO3 – solid solutions were determined by x-ray powder diffraction. Samples with the nominal compositions CaTi1 – y InyO3 – , synthesized in the range y=0.05–0.3, consisted of two phases: CaTiO3 – and a CaIn2O4-based phase. The compositions of the synthesized phases were checked by x-ray microanalysis. The electrical conductivity of the CaTi1 – x CrxO3 – (0 < × 0.2)solid solutions was measured as a function of oxygen partial pressure (0.21 × 104 to 1.0 × 10–11 Pa) at 900 and 1000°C. Cr doping of calcium titanate was shown to increase its conductivity. A mechanism of defect formation in doped calcium titanate was inferred from conductivity versus data.__________Translated from Neorganicheskie Materialy, Vol. 41, No. 4, 2005, pp. 475–478.Original Russian Text Copyright © 2005 by Murashkina, Demina.  相似文献   

15.
It is shown that the main characteristics of broadband radio inteference may be the voltage spectral density for pulsed interference and the power spectral density for both pulsed and smooth interference.Translated from Izmeritelnaya Tekhnika, No. 1, pp. 40–42, January, 2005.  相似文献   

16.
Methods of evaluation of thermodynamic and optical properties of multicomponent gases within a wide range of conditions are discussed. A databank on component composition, thermodynamic functions, spectral and group absorption coefficients, and Planck and Rosseland mean free paths of radiation for plasmas of air, water, silicon dioxide, and the Martian atmosphere (0.965 CO2+0.035 N2) is composed based on calculations.Academic Scientific Complex A. V. Luikov Institute of Heat and Mass Transfer of the Academy of Sciences of Belarus, Minsk, Belarus. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 68, No. 2, pp. 291–305, March–April, 1995.  相似文献   

17.
The electrical resistance and thermoelectric power of p-ZnAs2 are measured in the pressure range 15–50 GPa. The results attest to phase transitions at 7–10 and 25–30 GPa.Translated from Neorganicheskie Materialy, Vol. 41, No. 2, 2005, pp. 135–137Original Russian Text Copyright © 2005 by Mollaev, Arslanov, Saipulaeva, Babushkin, Tatur, Marenkin, Volfkovich.  相似文献   

18.
Quantitative estimates of the components of the error associated with the spectral characteristics of interference light filters, the curving of the surface of a liquid in a crater of the microplotter due to its motion, and capillary effects are given. Methods of identifying and limiting these errors are proposed.__________Translated from Izmeritelnaya Tekhnika, No. 2, pp. 40–42 February, 2005.  相似文献   

19.
A new original method is described for calibrating vacuum gauges making it possible to cover a range of intermediate pressures from 0.01–0.1 to 1–10 MPa. Experimental data confirm the efficiency of the suggested procedure.Translated from Izmeritelnaya Tekhnika, No. 12, pp. 43–44, December, 2004.This revised version was published online in April 2005 with a corrected cover date.  相似文献   

20.
After chemical polishing, the spectral response of bismuth silicate crystals shows a minimum at 0.41–0.43 m, where photosensitivity is comparable to that in the red spectral region (0.6–0.63 m).  相似文献   

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