共查询到20条相似文献,搜索用时 140 毫秒
1.
Li Wan Yiming Ren Bo Tang Xinhong Cheng Xuefei Zhang Dapeng Xu Hijun Luo Yunmi Huang 《Applied Physics A: Materials Science & Processing》2009,97(3):693-697
We report on the growth of NiSi film on Si(001) substrate with an orientation of NiSi[200]//Si[001]. Polarized Raman spectroscopy
was used to assign the symmetry of the NiSi Raman peaks. Raman peaks at 213 cm−1, 295 cm−1, and 367 cm−1 are assigned to be A
g
symmetry and peaks at 196 cm−1, and 254 cm−1 are B
3g
symmetry. 相似文献
2.
The magnetic hyperfine splitting frequencies of187WFe,182Re(j
π=2+)Ni,183ReNi,186ReNi,186ReFe and203PbFe in a zero external magnetic field have been determined by the NMR-ON method at about 7 mK as 225.56(6), 130.9(1), 98.17(4),
136.6(4), 1007.0(3) and 58.43(3) MHz, respectively. With the knowng-factors ofg(186Re, 1−)=1.739(3) andg(203Pb, 5/2−)=0.27456(20), the following hyperfine fields were deduced:B
HF(186ReNi)=−103.05(35) kG;B
HF(186ReFe)=−759.7(13) kG;B
HF(203PbFe)=+279.18(25) kG. Taking hyperfine anomalies into account, theg-factor of183Re was deduced as |g(183Re, 5/2+)|=1.267(6). With the assumption of Knight shift factorK=0, theg-factors of182Re and187W and the hyperfine field of187WFe were determined as |g(182Re, 2+)|=1.63(5), |g(187W, 3/2−)|=0.414(10) andB
HF(187WFe) =−714(18) kG. The large hyperfine anomaly was deduced to be183W Δ187W =−0.124(22). 相似文献
3.
Electron paramagnetic resonance (EPR) study of Cu2+-doped sodium zinc sulfate tetrahydrate is done at liquid nitrogen temperature. Two magnetically equivalent sites for Cu2+ are observed. The spin-Hamiltonian parameters determined by fitting the EPR spectra to the rhombic-symmetry crystalline field
are g
x
= 2.2356, g
y
= 2.0267, g
z
= 2.3472, A
x
= 27 × 10−4 cm−1, A
y
= 54 × 10−4 cm−1and A
z
= 88 × 10−4 cm−1. The ground state wave function is also determined. The g-anisotropy is evaluated and compared with the experimental value. With the help of optical study, the nature of bonding in
the complex is discussed. 相似文献
4.
Fourier transform infrared spectroscopy studies have been conducted to investigate the interaction among components in a system
of high molecular weight polyvinylchloride (PVC)–lithium trifluoromethanesulfonate (LiCF3SO3) incorporated with different type of plasticizers, namely, ethylene carbonate (EC), propylene carbonate (PC), and dibutylphthalate
(DBP). Interaction between PVC and LiCF3SO3 was confirmed by C–H rocking mode at 1,255 cm−1 for PVC shift to 1,252 cm−1 in PVC–LiCF3SO3. The plasticizers’ carbonyl (C=O) oxygen atom which carries lone pair electrons interact with Li+ of LiCF3SO3 and methine hydrogen of PVC in LiCF3SO3–plasticizer system and PVC–plasticizer system, respectively. Changes in peaks assigned to 1,264 cm−1 (ν
as(SO3)), 1,033 cm−1 (ν
s(SO3)), 1,181 cm−1 (ν
as(CF3)), 1,230 cm−1 (ν
s(CF3)), 765 cm−1 (δ
s(CF3)), 644 cm−1 (δ
s(SO3)), 578 cm−1 (δ
as(CF3)), and 519 cm−1 (δ
as(SO3)) indicate the occurrence of complexation in the PVC–LiCF3SO3 system, LiCF3SO3–plasticizer system, and PVC–LiCF3SO3–plasticizer system. 相似文献
5.
The electron paramagnetic resonance study of Cu2+-doped bis(l-asparaginato)Mg(II) is performed at room temperature. Two magnetically non-equivalent sites for Cu2+ are observed. The spin-Hamiltonian parameters evaluated by fitting spectra to the crystalline field of rhombic symmetry are
as follows: g
x
= 2.0420 ± 0.0002, g
y
= 2.0808 ± 0.0002, g
z
= 2.3600 ± 0.0002, A
x
= (99 ± 2) × 10−4 cm−1, A
y
= (108 ± 2) × 10−4 cm−1, A
z
= (140 ± 2) × 10−4 cm−1. The ground state wave function of Cu2+ is also determined. The g-anisotropy is estimated and compared with the experimental value. Further, with the help of optical study the nature of bonding
of a metal ion with different ligands in the complex is discussed. 相似文献
6.
J. C. Cruz V. Baglio S. Siracusano R. Ornelas L. Ortiz-Frade L. G. Arriaga V. Antonucci A. S. Aricò 《Journal of nanoparticle research》2011,13(4):1639-1646
Nanosized IrO2 electrocatalysts (d ~ 7–9 nm) with specific surface area up to 100 m2 g−1 were synthesized and characterized for the oxygen evolution reaction in a solid polymer electrolyte (SPE) electrolyzer. The
catalysts were prepared by a colloidal method in aqueous solution and a subsequent thermal treatment. An iridium hydroxide
hydrate precursor was obtained at ~100 °C, which was, successively, calcined at different temperatures from 200 to 500 °C.
The physico-chemical characterization was carried out by X-ray diffraction (XRD), thermogravimetry–differential scanning calorimetry
(TG–DSC) and transmission electron microscopy (TEM). IrO2 catalysts were sprayed onto a Nafion 115 membrane up to a loading of 3 mg cm−2. A Pt catalyst was used at the cathode compartment with a loading of 0.6 mg cm−2. The electrochemical activity for water electrolysis of the membrane-electrode assemblies (MEAs) was investigated in a single
cell SPE electrolyzer by steady-state polarization curves, impedance spectroscopy and chrono-amperometric measurements. A
maximum current density of 1.3 A cm−2 was obtained at 1.8 V and 80 °C for the IrO2 catalyst calcined at 400 °C for 1 h. A stable performance was recorded in single cell for this anode catalyst at 80 °C. The
suitable catalytic activity and stability of the most performing catalyst were interpreted in terms of proper combination
between nanostructure and suitable morphology. 相似文献
7.
M. A. Bolshov Y. A. Kuritsyn V. V. Liger V. R. Mironenko S. B. Leonov D. A. Yarantsev 《Applied physics. B, Lasers and optics》2010,100(2):397-407
A tunable diode laser absorption spectroscopy (TDLAS) technique and appropriate instrumentation was developed for the measurement
of temperature and water vapor concentrations in heated gases. The technique is based on the detection of the spectra of H2O absorption lines with different energies of low levels. The following absorption lines of H2O were used: 7189.344 cm−1 (E″=142 cm−1), 7189.541 cm−1 (E″=1255 cm−1), 7189.715 cm−1 (E″=2005 cm−1). Spectra were recorded using fast frequency scanning of a single distributed feedback (DFB) laser. A unique differential
scheme for the recording of the absorption spectra was developed. An optimal technique for fitting the experimental spectra
was developed. 相似文献
8.
R. Yu. Abdulsabirov I. I. Antonova S. L. Korableva N. M. Nizamutdinov V. G. Stepanov N. M. Khasanova 《Physics of the Solid State》1997,39(3):423-425
The orientational dependences of the EPR spectra of Fe3+-doped LiCaAlF6 single crystals (space group P31c, Z=2), grown at the Laboratory of Magnetic Radio Spectroscopy at Kazan’ State University, have been investigated in detail.
The spectrum is described by a trigonal spin Hamiltonian with the following parameters: B
20=40.072×10−4 cm−1, B
40=−5.799×10−4 cm−1, B
43=−4.281×10−4 cm−1, A
s=24.33±1, A
p=6.13±1, g
∥=g
⊥=2.00217±0.0003. A theoretical calculation of the hyperfine structure parameters shows that they are described quite well
when allowance is made for the overlapping of the wave functions of the paramagnetic center and the ligands (F−).
Fiz. Tverd. Tela (St. Petersburg) 39, 488–490 (March 1997) 相似文献
9.
ESR investigations on exchange coupled pairs of Cu ions in single crystals of Cu(dtc)2, isomorphously diluted with the corresponding diamagnetic zinc salt, are reported. The spin Hamiltonian parameters for the
coupled species (S=1) are:g
‖=2.1025,g
+=2.031,A=75.1×10−4 cm−1,B=14.8×10−4,D=276.0×10−4 cm−1 andE=46.7×10−4 cm−1. While theg andA tensors show tetragonal symmetry, the zeor-field splitting tensor is rhombic and has principal axes different from those
of theg andA tensors. Intensity measurements made down to 4.2 K indicate that the exchange is ferromagnetic with |FFF| ∼ 10 cm−1. Direct dipole-dipole interaction appears to be the major contribution to the zero-field splitting. A calculation on the
distributed point dipole model shows that dipolar interaction is considerably modified by the high covalency of the Cu-S bond
and accounts for the rhombic nature of the tensor. The possible exchange mechanisms in Cu(dtc)2—direct exchange and superexchange through the bridging sulphurs—are discussed. 相似文献
10.
We have recorded and investigated the ESR spectrum of vanadium-doped α-RbTiOPO4 single crystals in the temperature interval 77–300 K. Two types of structurally distinct centers, V1 and V2, with a 4:1 ratio
of the peak intensities were observed. The angular dependences of the resonance magnetic fields are described by a spin Hamiltonian
corresponding to axial symmetry with the parameters g
∥1=1.9305, g
⊥1=1.9565, A
∥1=−168.2×10−4cm−1, and A
⊥1=−54.3×10−4cm−1 for V1 centers and g
∥2=1.9340, g
⊥2=1.9523, A
∥2=−169.0×10−4cm−1, and A
⊥2=−55.2×10−4cm−1 for V2 centers. A model of a paramagnetic center is proposed: The vanadium ions replace titanium ions in two structurally
distinct positions Ti1 and Ti2 (V1 and V2 centers, respectively). The possibility that a VO2+ ion forms when α-RbTiOPO4 crystals and crystals of the KTP group (KTiOPO4, NaTiOPO4, α-and β-LiTiOPO4), studied earlier, are doped with vanadium is discussed.
Fiz. Tverd. Tela (St. Petersburg) 40, 534–536 (March 1998) 相似文献
11.
P. Kienle 《Hyperfine Interactions》1996,103(1):49-58
Experiments which led to the discovery of the heaviest, self-conjugated double magic nucleus100Sn and the bound-state β-decay of completely ionized187Re are presented.100Sn was produced by fragmentation of 1.1 A GeV124Xe beams, separated and implanted in a 4π Si-stack detector. From its decay a half-lifeT
1/2=0.94(+0.54, −0.27) s and a β+ endpoint energy ofE
β=3.4(+0.7, −0.3) MeV were determined for the 0+−1+ Gamov-Teller transition. Completely stripped187Re75+ was produced and stored in a coolerring with an energy of 351 A MeV for several hours. The products of bound-state β-decay
of187Re75+ were detected by two independent methods, which allowed to determine a half-life ofT
1/2=33±6 y for this decay, which is of importance for the calibration of the Re/Os nucleosynthesis chronometer. 相似文献
12.
Quantitative correlations between the intensity of the crystalline band at 1144 cm−1 (A
1144) normalized to the intensity of the C–O stretching band at 1094 cm−1 (A
1094) in IR spectra of PVA films and the degree of crystallinity (α) of these films measured by an x-ray diffraction method were
investigated. It was found that α and A
1144/A
1094 were related by the linear dependence α (%) = a + b(A
1144/A
1094) with correlation coefficient 0.999 for α values in the range 18–60%. 相似文献
13.
Electron paramagnetic resonance studies have been carried out at 300 K on the Cu(II)-doped [Zn(C3H2O4)2(H2O)2] system in single-crystal and powder forms in order to rationalize the low parallel 63Cu hyperfine value. Angular variation of the hyperfine resonances in the three orthogonal planes shows the presence of only
one magnetic site with g and A values equal to g
zz
= 2.455, g
yy
= 2.121, g
xx
= 2.105 and A
zz
= 160.9 · 10−4 cm−1, A
yy
= 12.5 · 10−4 cm−1, A
xx
= 7.35 · 10−4 cm−1. The crystal structure of the host lattice is isostructural with the corresponding cobalt complex and contains two molecules
per unit cell. The low magnitude of A
zz
value for the complex is rationalized in terms of an admixture of the
ground state with the
excited state and delocalization of the unpaired spin density onto the ligands. In addition, the highest hyperfine value
obtained from the single-crystal data (160.9 · 10−4 cm−1) is considerably larger than that obtained from the powder spectrum (138 · 10−4 cm−1).
Authors' address: P. Sambasiva Rao, Department of Chemistry, Pondicherry University, Pondicherry 605014, India 相似文献
14.
P. Ortwein W. Woiwode S. Wagner M. Gisi V. Ebert 《Applied physics. B, Lasers and optics》2010,100(2):341-347
A high-resolution spectrometer based on a vertical-cavity surface-emitting laser (VCSEL) was developed and used to determine
the line strength S(T
0)=12.53(11)×10−21 cm−1/(molec cm−2) and the self-broadening coefficient
g0HCl=0.021787(61)\gamma^{0}_{\mathrm{HCl}}=0.021787(61)
cm−1/atm of the R(3) absorption line in the first rovibrational overtone (2←0) band of H35Cl. Furthermore, the first laser-based high-pressure study on the pressure broadening of HCl by He, N2 and
O2(g0N2=0.07292(5)\mathrm{O}_{2}(\gamma^{0}_{\mathrm{N}_{2}}=0.07292(5)
cm−1/atm,
g0He=0.02113(1)\gamma^{0}_{\mathrm{He}}=0.02113(1)
cm−1/atm,
g0O2=0.03978(6)\gamma^{0}_{\mathrm{O}_{2}}=0.03978(6)
cm−1/atm) is presented covering pressures of up to 1 MPa. The results are compared to previously available low-pressure data. 相似文献
15.
A. A. Kaminskii H. Rhee H. J. Eichler K. Ueda K. Oka H. Shibata 《Applied physics. B, Lasers and optics》2008,93(4):865-872
We report the experimental investigations of nonlinear-laser effects in LuVO4 vanadate under one-micron picosecond Nd3+:Y3Al5O12 pumping. In this tetragonal host-crystal for Ln3+ lasants for the first time we excited ultra-broad, more than one and half octave (13500 cm−1) Raman induced Stokes and anti-Stokes generation combs and observed multi-step cascaded parametric χ
(3)-lasing in UV spectral region. All generation lines were identified and attributed to SRS-promoting modes of the crystal (ω
SRS1≈900 cm−1 and ω
SRS2≈113 cm−1). We classified this vanadate as a promising material for self-Raman laser converters. 相似文献
16.
The absorption spectra, fluorescence spectrum and fluorescence decay curve of Nd3+ ions in CaNb2O6 crystal were measured at room temperature. The peak absorption cross section was calculated to be 6.202×10−20 cm2 with a broad FWHM of 7 nm at 808 nm for E//a light polarization. The spectroscopic parameters of Nd3+ ions in CaNb2O6 crystal have been investigated based on Judd-Ofelt theory. The parameters of the line strengths Ω
t
are Ω
2=5.321×10−20 cm2,Ω
4=1.734×10−20 cm2,Ω
6=2.889×10−20 cm2. The radiative lifetime, the fluorescence lifetime and the quantum efficiency are 167 μs, 152 μs and 91%, respectively. The fluorescence branch ratios are calculated to be β
1=36.03%,β
2=52.29%,β
3=11.15%,β
4=0.533%. The emission cross section at 1062 nm is 9.87×10−20 cm2. 相似文献
17.
G. B. Scott D. E. Lacklison J. L. Page J. Hewett 《Applied Physics A: Materials Science & Processing》1976,9(1):71-77
The absorption (α) and Faraday rotation (θ) spectra of 14 garnets belonging to the series Bi
x
Sm3-x
Fe5-y
Ga
y
O12 (0<x<1.05, 0.8<y<1.15) have been measured between 15 000 cm−1 and 19 000 cm−1. The figure of merit (θ/α) at 17 850 cm−1 (560 nm) increases linearly with increasing bismuth concentration up tox∼0.6 where it begins to increase less rapidly. For operation of magneto-optic display devices at 17 850 cm−1 there is no advantage in using garnets in this series withx>0.8. The Faraday rotation at 17 850 cm−1 increases linearly with bismuth concentration whereas the absorption coefficient increases more rapidly. The presence of
Bi3+ increases the intensity of all Fe3+ pair transitions in the garnet system as a result of the increased superexchange induced by Bi3+. This is in keeping with the observation that the intensity of the6A1g
(S)→4T1g
(G) transition in (RE)3Fe5O12 (RE=Er, Y, Dy, Gd, Eu) increases on traversing the above RE series as do the Curie temperatures of these iron garnets. 相似文献
18.
J. J. Camacho M. Santos L. Díaz L. J. Juan J. M. L. Poyato 《Applied Physics A: Materials Science & Processing》2010,99(1):159-175
A spectroscopic study of ambient air plasma, initially at room temperature and pressures ranging from 32 to 101 kPa, produced
by high-power transverse excitation atmospheric (TEA) CO2 laser (λ=9.621 and 10.591 μm; τ
FWHM≈64 ns; power densities ranging from 0.29 to 6.31 GW cm−2) has been carried out in an attempt to clarify the processes involved in laser-induced breakdown (LIB) air plasma. The strong
emission observed in the plasma region is mainly due to electronic relaxation of excited N, O and ionic fragments N+. The medium-weak emission is due to excited species O+, N2+, O2+, C, C+, C2+, H, Ar and molecular band systems of N
2+(_{2}^{+}(
B
2\varSigma u+^{2}\varSigma _{\mathrm{u}}^{+}
–X
2\varSigma g+)^{2}\varSigma _{\mathrm{g}}^{+})
, N2(C3
Π
u–B3
Π
g), N
2+(_{2}^{+}(
D2
Π
g–A2
Π
u) and OH(A2
Σ
+–X2
Π). Excitation temperatures of 23400±700 K and 26600±1400 K were estimated by means of N+ and O+ ionic lines, respectively. Electron number densities of the order of (0.5–2.4)×1017 cm−3 and (0.6–7.5)×1017 cm−3 were deduced from the Stark broadening of several ionic N+ and O+ lines, respectively. Estimates of vibrational and rotational temperatures of N
2+_{2}^{+}
electronically excited species are reported. The characteristics of the spectral emission intensities from different species
have been investigated as functions of the air pressure and laser irradiance. Optical breakdown threshold intensities in air
at 10.591 μm have been measured. 相似文献
19.
Guo-Yu Lan Yang-Wei Lin Zong-Hong Lin Huan-Tsung Chang 《Journal of nanoparticle research》2010,12(4):1377-1388
This article describes the synthesis of highly water-soluble Zn
x
Hg1−x
Se
y
S1−y
quantum dots (QDs) in aqueous solution through a simple photo-assisted reaction between ZnSe QDs and mercury(I) nitrate dihydrate
[Hg2(NO3)2·2H2O]. In order to deduce the optimal synthesis conditions, we varied several parameters, including the concentrations of mercaptosuccinic
acid (MSA) and Hg2(NO3)2·2H2O, the illumination time, and the reaction temperature. When irradiated at temperatures below 80 °C, the ZnSe QDs reacted
with the S2− ions formed rapidly from MSA and the Hg2+ ions formed from Hg2
2+ ions to form Zn
x
Hg1−x
Se
y
S1−y
QDs through a process of photo-etching and surface combination. Under different conditions, we prepared a series of Zn
x
Hg1−x
Se
y
S1−y
QDs that emit fluorescence at the maximum wavelengths ranging from 405 to 760 nm. Inductively coupled plasma-mass spectrometry
and transmission electron microscopy/energy dispersive spectrometry revealed that the content of Hg in the Zn
x
Hg1−x
Se
y
S1−y
QDs was greater when the synthesis was conducted at higher temperature. The Zn0.88Hg0.12Se0.44S0.56 QDs exhibit improved photostability than crude ZnSe QDs and possess long lifetimes (τ1 ~ 38 ns and τ2 ~ 158 ns). 相似文献
20.
A nanoparticle TiO2 solid-state photoelectrochemical cell utilizing as a solid electrolyte of poly(acrylonitrile)–propylene–carbonate–lithium
perchlorate (PAN–PC–LiClO4) has been fabricated. The performance of the device has been tested in the dark and under illumination of 100-mW cm−2 light. A nanoparticle TiO2 film was deposited onto indium tin oxide-covered glass substrate by controlled hydrolysis technique assisted with spin-coating
technique. The average grain size for the TiO2 film is 76 nm. LiClO4 salt was used as a redox couple. The room temperature conductivity of the electrolyte is 4.2 × 10−4 S cm−1. A graphite electrode was prepared onto a glass slide by electron beam evaporation technique. The device shows the rectification
property in the dark and shows the photovoltaic effect under illumination. The best J
sc and V
oc of the device were 2.82 μA cm−2 and V
oc of 0.58 V, respectively, obtained at the conductivity of 4.2 × 10−4 S cm−1 and intensity of 100 mW cm−2. The J
sc was improved by about three times by introducing nanoparticle TiO2 and by using a solid electrolyte of PAN–PC–LiClO4 replacing PVC–PC–LiClO4 in the device. The current transport mechanism of the cell is also presented in this paper. 相似文献