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1.
Wen-Yang Chang Te-Hua Fang Yu-Cheng Lin 《Applied Physics A: Materials Science & Processing》2008,92(3):693-701
Physical characteristics of polyimide films, including optical, micro/nano mechanical, and thermophysical characteristics
were investigated using a photometric, a nanoindentation, and a thermomechanical analyzer for applications in flexible sensors.
Experimental results show that UV light cannot transmit into the polyimide films. The transmittances, with a maximum of about
86%, at VIS and near IR lights decrease with increasing PI film thicknesses. The mechanical characteristics were determined
using tensile, bending moment, and nanoindentation testing. The stress–strain curve approximated bilinear characteristics,
the load–unload bending moment exhibited hysteresis, and nanoindentation generated elastic energy dissipation in the loading–unloading
region. Nanoindentation showed an almost uniform hardness and a reduced Young’s modulus of about 0.181±0.03 and 3.21±0.06 GPa,
respectively, when the penetrating depth was more than about 2 μm. Thermophysical characteristics were greatly influenced
on 8.3 and 25 μm specimens due to the higher relaxation of thin PI films. The thermal expansion remained steady when the thickness
was over 50 μm. The results show that PI films have potential in flexible sensing and higher temperature fabrication. 相似文献
2.
G. Lehmann P. Hess S. Weissmantel G. Reisse P. Scheible A. Lunk 《Applied Physics A: Materials Science & Processing》2002,74(1):41-45
Cubic boron nitride (c-BN) films of 200–420 nm thickness and high phase purity were deposited on silicon (100) substrates
by ion-assisted pulsed laser deposition (IA PLD)from a boron nitride target using a KrF-excimer laser, and by plasma-enhanced
physical vapor deposition (PE PVD)with a hollow-cathode arc evaporation device. In order to improve the c-BNfilm adhesion,
hexagonal boron nitride (h-BN) films with 25–50 nm thickness were used as buffer layers. The density and Young’s modulus of
the c-BNfilms were obtained by investigating the dispersion of surface acoustic waves. In data analysis a two-layer model
was applied in order to take the influence of the h-BNlayer into consideration. The values for the density vary from 2.95±0.25 g/cm3to 3.35±0.3 g/cm3, and those for the Young’s modulus from 420±40 GPa to 505±30 GPa. The results are compared with literature values reported
for nanocrystalline films, polycrystalline disks and single crystal c-BN.
Received: 26 March 2001 / Accepted: 29 March 2001 / Published online: 25 July 2001 相似文献
3.
Guanghui Xu Qiang Zhang Weiping Zhou Jiaqi Huang Fei Wei 《Applied Physics A: Materials Science & Processing》2008,92(3):531-539
This study sought to produce carbon nanotube (CNT) pulp out of extremely long, vertically aligned CNT arrays as raw materials.
After high-speed shearing and mixing nitric acid and sulfuric acid, which served as the treatment, the researchers produced
the desired pulp, which was further transformed into CNT paper by a common filtration process. The paper’s tensile strength,
Young’s modulus and electrical conductivity were 7.5 MPa, 785 MPa and 1.0×104 S/m, respectively, when the temperature of the acid treatment was at 110°C. Apart from this, the researchers also improved
the mechanical property of CNT paper by polymers. The CNT paper was soaked in polyethylene oxide, polyvinyl pyrrolidone, and
polyvinyl alcohol (PVA) solution, eventually making the CNT/PVA film show its mechanical properties, which increased, while
its electrical conductivity decreased. To diffuse the polymer into the CNT paper thoroughly, the researchers used vacuum filtration
to fabricate a CNT/PVA film by penetrating PVA into the CNT paper. After a ten-hour filtration, the tensile strength and Young’s
modulus of CNT/PVA film were 96.1 MPa and 6.23 GPa, respectively, which show an increase by factors of 12 and 7, respectively,
although the material’s electrical conductivity was lowered to 0.16×104 S/m. 相似文献
4.
F. Monteverde 《Applied Physics A: Materials Science & Processing》2006,82(2):329-337
A fully dense ZrB2 ceramic containing 10 vol. % ultra-fine α-SiC particulate was successfully hot pressed at 1900 °C for 20 min and 40–50 MPa
of applied pressure. Faceted ZrB2 grains (average size ≈3 μm) and SiC particles dispersed regularly characterized the base material. No extra secondary phases
were found. The introduction of the ultra-fine α-SiC particulate was recognized as the key factor that enabled both the control
of the diboride grain growth and the achievement of full density. The mechanical properties offered an interesting combination
of data: 4.8±0.2 MPafracture toughness, 507±4 GPa Young’s modulus, 0.12 Poisson’sratio, and 835±35 MPa flexural strength at room temperature.
The flexural strength measured at 1500 °C (in air) provided values of 300±35 MPa. The incorporated ultra-fine α-SiC particulate
was fundamental, sinterability apart, to enhancing the strength and oxidation resistance of ZrB2. The latter property was tested at 1450 °C for 20 h in flowing dry air. In such oxidizing conditions, the formation of a
thin external borosilicate glassy coating supplied partial protection for the faces of the material exposed to the hot environment.
The oxidation attack penetrated into the material’s bulk and created a 200-μm-thick zirconia scale. The SiC particulate included
in the oxide scale, lost by active oxidation, left carbon-based inclusions in the formerly occupied sites.
PACS 81.05.Je; 81.20.Ev; 81.70.Bt 相似文献
5.
A.V. Podlipensky K.V. Yumashev N.V. Kuleshov H.M. Kretschmann G. Huber 《Applied physics. B, Lasers and optics》2003,76(3):245-247
Spectroscopic data of a V3+:YAG passive Q-switch crystal were measured. The absorption recovery time was determined to be of 37±7 ns and the ground state
absorption cross section was estimated to be 0.7×10-18 cm2 at 1.44 μm and 3.5×10-18 cm2 at 1.34 μm. Passively Q-switched operation of diode pumped 1.44 μm and 1.3 μm Nd:YAG lasers was demonstrated using this crystal
as saturable absorber. Average output powers of 1.42 W (1.44 μm) and 1.56 W (1.34 μm) and pulse energies of 24 μJ (1.44 μm)
and 25 μJ (1.34 μm) were observed, respectively.
Received: 19 August 2002 / Published online: 12 February 2003
RID="*"
ID="*"Corresponding author. Fax: +49-40/42838-6281, E-mail: kretschmann@physnet.uni-hamburg.de 相似文献
6.
I. P. Chernov Yu. P. Cherdantsev A. M. Lider Yu. I. Tyurin N. S. Pushilina S. V. Ivanova 《Journal of Surface Investigation: X-ray, Synchrotron and Neutron Techniques》2010,4(2):255-261
The results of studying the hydrogen permeability and physicomechanical properties of zirconium alloy irradiated with a pulse
electron beam are presented. It is established that, with an increase in the beam energy, a surface layer of this material
is hardened to depths of about 2.5 μμm. The depth distribution of Young’s modulus values of zirconium alloy confirms the obtained
results. The study of the hydrogen permeability of this material has shown that, after hydrogen charging of samples, the hydrogen
concentration in a sample treated at an energy density of 18 J/cm2 is 2.5–3 times lower than that of the initial material charged with hydrogen. 相似文献
7.
The dependences of the internal friction and the Young’s modulus defect of polycrystalline indium on the oscillatory strain
amplitude have been studied over a wide range of temperatures (7–320 K) and oscillatory strain amplitudes (10−7−3.5 × 10−4) at oscillatory loading frequencies of about 100 kHz. It has been revealed that the amplitude dependences of the internal
friction and the Young’s modulus defect include stages associated with the interaction of dislocations with point defects
and the interdislocation interaction. The temperature range characterized by the formation of point-defect atmospheres (the
Cottrell atmospheres) near dislocations in indium has been determined. 相似文献
8.
A combination Monte Carlo and equivalent-continuum simulation approach was used to investigate the structure-mechanical property
relationships of titania nanoparticle deposits. Films of titania composed of nanoparticle aggregates were simulated using
a Monte Carlo approach with diffusion-limited aggregation. Each aggregate in the simulation is fractal-like and random in
structure. In the film structure, it is assumed that bond strength is a function of distance with two limiting values for
the bond strengths: one representing the strong chemical bond between the particles at closest proximity in the aggregate
and the other representing the weak van der Waals bond between particles from different aggregates. The Young’s modulus of
the film is estimated using an equivalent-continuum modeling approach, and the influences of particle diameter (5–100 nm)
and aggregate size (3–400 particles per aggregate) on predicted Young’s modulus are investigated. The Young’s modulus is observed
to increase with a decrease in primary particle size and is independent of the size of the aggregates deposited. Decreasing
porosity resulted in an increase in Young’s modulus as expected from results reported previously in the literature. 相似文献
9.
2 laser standards. Using this technique, we can tune the CO laser frequency with absolute frequency control within the gain
profile of each laser transition. The frequency uncertainty is smaller than 15 kHz, corresponding to Δν/ν=2.5×10-10. Moreover, we obtain a reduction of the CO laser linewidth by a factor of 2 down to 65 kHz, corresponding to a spectral resolution
of δν/ν=1×10-9. With this outstanding accuracy and resolution we studied the shape of saturation dips in rovibrational lines of CO and carbonyl
sulfide (OCS) at low pressure (<5 Pa). The self-pressure-broadening rate of CO was found to be γc=+83(7) kHz/Pa in this pressure region. This value is about four times higher than values resulting from previous measurements
at much higher pressures. To our knowledge the measurements described here are the first line-shape studies with sub-Doppler
resolution in the 5 μm spectral region.
Received: 4 November 1996 相似文献
10.
M. Moner-Girona E. Martínez J. Esteve A. Roig R. Solanas E. Molins 《Applied Physics A: Materials Science & Processing》2002,74(1):119-122
Materials’ endurance to mechanical stress is desirable from a technological point of view. In particular, in the case of silica
aerogels, an improvement of the material elasticity is needed for some applications. Carbon–silica aerogel composites have
been obtained and their mechanical properties, Young’s modulus, elastic parameter and hardness, have been evaluated with a
dynamical, non-destructive microindentation technique. Large changes are found in Young’s modulus when only a small amount
of carbon is added. This is clearly shown in the shape of the indentation curves as well as in the increase of the elastic
parameter value, which evaluates the percentage of elasticity versus plasticity. Young’s modulus values obtained for carbon–silica
aerogels show a similar variation with the carbon mass fraction to that predicted by a commonly used model for composite materials.
The measured hardness values corresponding to the total elastoplastic deformation do not show such a prominent dependency
on the carbon mass fraction as the elastic parameter and Young’s modulus do and they are similar to those measured for the
pure-silica aerogel.
Received: 18 May 2001 / Accepted: 30 July 2001 / Published online: 30 October 2001 相似文献
11.
S.I. Dolgaev J.M. Fernández-Pradas J.L. Morenza P. Serra G.A. Shafeev 《Applied Physics A: Materials Science & Processing》2006,83(3):417-420
We report the growth of conical microstructure arrays on a stainless steel substrate under multi-pulsed Nd:YAG laser irradiation
(wavelength of 1.064 μm, pulse duration of 300 ns, repetition rate of 5 kHz) at atmospheric air pressure. The average period
of microcones is 70 μm, and they protrude 50–60 μm above the substrate. At an air pressure of 1 Pa, the well-defined conical
shape is lost and the resulting microstructure shows a smaller period and height. At 10-3 Pa, only small protrusions separated by about 5 μm are observed. The different mechanisms involved in the growth of conical
microstructures are discussed.
PACS 42.62.-b; 81.65.-b 相似文献
12.
E. György I.N. Mihailescu P. Serra A. Pérez del Pino J.L. Morenza 《Applied Physics A: Materials Science & Processing》2002,74(6):755-759
We report micrometre-sized crown-like structure growth on a Ti surface by multipulse Nd:YAG (λ=1.064 μm,τ=170 ns) laser irradiation
in air at atmospheric pressure. The irradiation was performed at 8×107 W/cm2 laser-pulse intensity, below the ablation threshold. A ring-shape structure develops in the centre of the irradiation spot
after the action of five laser pulses. The further increase of the laser-pulse number leads gradually to a crown-like structure,
which has, for 150 pulses, a height of 120–140 μm above the non-irradiated Ti surface. The forming crater’s depth does not
exceed the height of the grown structure. In the neighbouring zone, after the action of 25 laser pulses, microcracks of the
oxide surface layer develop. With the next pulses this leads to the formation of a surface microrelief. The crown-like-structure
growth is originated by molten material movement attributed to the laser-induced plasma-recoil pressure.
Received: 6 June 2001 / Accepted: 6 January 2002 / Published online: 26 March 2002 相似文献
13.
S.I. Dolgaev S.V. Lavrishev A.A. Lyalin A.V. Simakin V.V. Voronov G.A. Shafeev 《Applied Physics A: Materials Science & Processing》2001,73(2):177-181
The formation and development of the large-scale periodic structures on a single crystal Si surface are studied upon its evaporation
by pulsed radiation of a copper vapor laser (wavelength of 510.6 nm, pulse duration of 20 ns). The development of structures
occurs at a high number of laser shots (∼104) at laser fluence of 1–2 J/cm2 below optical breakdown in a wide pressure range of surrounding atmosphere from 1 to 105 Pa. The structures are cones with angles of 25, which grow towards the laser beam and protrude above the initial surface
for 20–30 μm. It is suggested that the spatial period of the structures (10–20 μm) is determined by the capillary waves period
on the molten surface. The X-ray diffractometry reveals that the modified area of the Si substrate has a polycrystalline structure
and consists of Si nanoparticles with a size of 40–70 nm, depending on the pressure of surrounding gas. Similar structures
are also observed on Ge and Ti.
Received: 12 February 2000 / Accepted: 28 March 2000 / Published online: 20 June 2001 相似文献
14.
G.K. Kitaeva I.I. Naumova A.A. Mikhailovsky P.S. Losevsky A.N. Penin 《Applied physics. B, Lasers and optics》1998,66(2):201-205
3 crystals are measured in the transparency region (with the accuracy ±0.0002) and for the upper phonon polariton branch (with
the accuracy ±0.003–±0.05), from 0.44 μm up to 10.5 μm. The method of spontaneous parametric light scattering is used for
measurement of the ordinary refractive index dispersion in the mid-infrared region and for determination of the domain grating
period d=5.6±0.2 μm in the periodically-poled crystal.
Received: 29 January 1997/Revised version: 10 July 1997 相似文献
15.
Organic–inorganic composite microspheres with PS as a core and CeO2 as a shell were synthesized by in situ chemical precipitation method. The size of PS core was 117, 163, 206, and 241 nm,
respectively, and the shell thickness was about 10 nm. The CeO2 shell was composed of a large number of nanoparticles, of which the size was 4–6 nm. Atomic force microscopy was employed
to probe the mechanical properties of core–shell structured ceria-coated polystyrene (PS/CeO2) composite microspheres. On the basis of Hertz’s theory of contact mechanics, compressive moduli were measured by the analysis
of force–displacement curves captured on the microsphere samples. For a fixed CeO2 shell thickness, the Young’s modulus of composite microspheres increased with an increase of PS core size. The calculated
Young’s moduli (E) values of composites for 136, 185, 242, and 261 nm in diameter were 5.78 ± 0.9, 7.23 ± 1.3, 11.46 ± 1.7, and 14.54 ± 1.4 GPa,
respectively. The results revealed the effect of the CeO2 shell on the elastic deformation of the PS core. This approach will provide fundamental insights into the actual role of
organic/inorganic core/shell composite abrasives in chemical mechanical polishing. 相似文献
16.
Yasemin ?. ?iftci Kemal ?olako?lu Cansu ?oban Engin Delig?z 《Central European Journal of Physics》2012,10(1):197-205
The structural, elastic and thermodynamic characteristics of CeGa2 compound in the AlB2 (space group: P6/mmm) and the omega trigonal (space group: P-3m1) type structures are investigated using the methods of density
functional theory within the generalized gradient approximation (GGA). The thermodynamic properties of the considered structures
are obtained through the quasi-harmonic Debye model. The results on the basic physical parameters, such as the lattice constant,
the bulk modulus, the pressure derivative of bulk modulus, the phase-transition pressure (P
t
) from P6/mmm to P-3m1 structure, the second-order elastic constants, Zener anisotropy factor, Poisson’s ratio, Young’s modulus,
and the isotropic shear modulus are presented. In order to gain further information, the pressure and temperature-dependent
behavior of the volume, the bulk modulus, the thermal expansion coefficient, the heat capacity, the entropy, Debye temperature
and Grüneisen parameter are also evaluated over a pressure range of 0–6 GPa and a wide temperature range of 0–1800 K. The
obtained results are in agreement with the available experimental and the other theoretical values. 相似文献
17.
Y.H. Cheng B.K. Tay S.P. Lau X.L. Qiao J.G. Chen Z.H. Sun C.S. Xie 《Applied Physics A: Materials Science & Processing》2002,75(3):375-380
Super-hard and elastic carbon nitride films have been synthesized by using an off-plane double-bend filtered cathodic vacuum
arc combined with a radio-frequency nitrogen-ion beam source. A nanoindenter was used to determine the micromechanical properties
of the deposited films. X-ray photoelectron spectroscopy was used to study the composition and bonding structure of the deposited
films. The influence of nitrogen ion energy on the structure and micromechanical properties of the deposited films was systematically
studied. As the nitrogen ion energy is increased, the microhardness, Young’s modulus and elastic recovery also increase, reaching
a maximum of 47 GPa, 400 GPa, and 87.5%, respectively, at a nitrogen ion energy of 100 eV. Further increase in nitrogen ion
energy results in a decrease in microhardness, Young’s modulus and elastic recovery of the deposited films. The formation
of five-membered rings, as indicated by XPS, which causes bending of the basal planes and forms a three-dimensional rigid
covalent bond network, contributes to the super-hardness, Young’ s modulus and high elastic recovery of the films deposited
at a nitrogen ion energy of 100 eV.
Revised version: 29 October 2001 / Accepted: 7 November 2001 / Published online: 2 May 2002 相似文献
18.
S.A. Starostin I.V. Kochetov P.J.M. Peters Y.B. Udalov W.J. Witteman A.P. Napartovich 《Applied physics. B, Lasers and optics》2000,71(4):491-494
The performance of a RF excited cw atomic xenon laser at wavelengths of 2.03 μm and 2.65 μm was studied theoretically and
experimentally as a function of electrode distance. Results for inter-electrode distances from 2 to 0.25 mm are presented.
A high pumping rate resulted in strong 40 mW cw amplified spontaneous emission at 2.65 μm wavelength from the configuration
with the smallest distance of 0.25 mm between the electrodes. The maximum laser output of 2.7 W (0.24 W/cm3) was obtained with an active medium volume of 2×15×370 mm3 whereas the maximum specific output of 1.9 W/cm3 was received for an active medium volume of 0.25×2.25×370 mm3. A fluid model of the RF discharge was developed to analyze the laser behavior for different distances between the electrodes.
Received: 30 November 1999 / Revised version: 21 April 2000 / Published online: 6 September 2000 相似文献
19.
Y. Duan G. Tang L. Qin L. Shi 《The European Physical Journal B - Condensed Matter and Complex Systems》2008,66(2):211-215
Elasticity and polarization of GaxAl1-xN alloys subjected
to uniaxial and homogeneous biaxial compression are calculated using
first-principles methods. The uniaxial compression along the c-axis
reduces Young’s modulus along the c-axis, and enhances bulk
modulus and total polarization, whereas the biaxial compression in
the plane perpendicular to the c-axis enhances bulk and Young’s
moduli. It is also found that when the in-plane biaxial compression
is applied by constraining the a-axis lattice constant to that of
AlN, the bulk and Young’s moduli dramatically increase with
increasing Ga concentration, and the total polarization could be
suppressed, even annihilated, and finally enhanced by controlling Ga
concentration. 相似文献
20.
M. Jackson E.M. Telles M.D. Allen K.M. Evenson 《Applied physics. B, Lasers and optics》2001,72(7):815-818
A significantly improved far-infrared laser has been used to generate optically pumped laser emissions from 26 to 150 μm for
CD3OH. Using an X–V-pumping geometry, several new laser emissions have been found for CD3OH. In addition, an increase in power, by factors from 10 to 1000, for many of the previously known shorter-wavelength laser
lines, below 100 μm, has been observed. Frequency measurements for several lines have also been performed and have been reported
to a fractional uncertainty up to ±2×10-7, permitting the spectroscopic assignment of the laser transition. One of the frequency-measured lines, 44.256 μm observed
using the 10R34 pump, has confirmed the assignment of the previously reported FIR emission (n,K;J)=(1,7;20)?(0,8;20)A in the
ground vibrational state.
Received: 26 October 2000 / Published online: 7 February 2001 相似文献