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1.
D. Tomida S. Kenmochi T. Tsukada K. Qiao C. Yokoyama 《International Journal of Thermophysics》2007,28(4):1147-1160
Thermal conductivities are reported for a series of 1-alkyl-3-methylimidazolium hexafluorophosphates having butyl, hexyl,
and octyl groups, which are expressed by [bmim][PF6], [hmim][PF6], and [omim][PF6], respectively. The experimental method used was a transient short-hot-wire method. Since only a small amount of sample liquid
is required, this method was found to be effective for the thermal-conductivity measurements of ionic liquids (ILs). The experimental
temperatures ranged from 294 to 335 K at pressures up to 20 MPa. The values of the thermal conductivities of ILs at normal
pressure are similar to those of benzene. It was found that an effect of the length of the alkyl chain on the thermal conductivities
in ILs is negligible. From the data for the thermal conductivity and viscosity at 293.15 K and 0.1 MPa of ILs and normal alkanes,
a simple correlation was developed based on the Mohanty theory. From comparisons between the thermal conductivities of ILs
and those of organic liquids (n-hexane, benzene, and methanol), the temperature and pressure dependences of the thermal conductivity of ILs are relatively
weak. 相似文献
2.
The viscosities of 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim] [PF6]) and 1-butyl-3-methylimidazolium tetrafluoroborate ([bmim][BF4]) were measured by using a rolling-ball viscometer. The experimental temperatures were from 293.15 to 353.15 K, and the pressures were from 0.1 to 20.0 MPa.Paper presented at the Seventh Asian Thermophysical Properties Conference, August 23–28, 2004, Hefei and Huangshan, Anhui, P. R. China. 相似文献
3.
Ab initio molecular dynamics studies have been carried out on the room temperature ionic liquid, 1,n-butyl,3-methylimidazolium hexafluorophosphate ([bmim][PF6]) and supercritical carbon dioxide mixture at room temperature and experimental density. Partial radial distribution functions
(RDF) for different sites have been computed to see the organization of CO2 molecules around the ionic liquid. Several partial RDFs around the carbon atom of CO2 molecule are compared to find out that the CO2 has specific interaction with a carbon atom present in the imidazolium ring. The CO2 is also found to be very well organized around the terminal carbon atom of the butyl chain. The partial RDFs for the oxygen
atoms around oxygen and carbon atoms of the CO2 suggests that there is very good organization of CO2 molecules around themselves even in the [bmim][PF6]-CO2 mixture. The instantaneous quadrupole moment tensor has been calculated for the anion and the cation. The ensemble average
of diagonal components of quadrupole moment tensor of the cation have finite values, whereas the off-diagonal components of
the cation and both the diagonal and off-diagonal components of the anion have the value of zero with a large standard deviation.
The CPMD studies performed on CO2 clusters reveals the greater tendency of the clusters with more CO2 units, to deviate from the linear geometry. 相似文献
4.
D. Tomida S. Kenmochi T. Tsukada K. Qiao C. Yokoyama 《International Journal of Thermophysics》2010,31(10):1888-1895
Experimental results for the thermal conductivities of imidazolium-based ionic liquid + CO2 mixtures are reported. The thermal conductivities were measured with a transient short-hot-wire method. The experimental
temperatures were from 294 K to 334 K, and pressures were 10.0 MPa and 20.0 MPa. The CO2 mole fractions of the mixtures covered a range up to 0.42. It was found that the thermal conductivities of ionic liquids
have a very small CO2 mole fraction dependence. 相似文献
5.
A thermodynamic property model with new mixing rules using the Helmholtz free energy is presented for the binary mixture of
methane and hydrogen sulfide based on experimental Pρ Tx data, vapor–liquid equilibrium data, and critical-point properties. The binary mixture of methane and hydrogen sulfide shows
vapor–liquid–liquid equilibria and a divergence of the critical curve. The model represents the existing experimental data
accurately and describes the complicated behavior of the phase equilibria and the critical curve. The uncertainty in density
calculations is estimated to be 2%. The uncertainty in vapor–liquid equilibrium calculations is 0.02 mole fraction in the
liquid phase and 0.03 mole fraction in the vapor phase. The model also represents the critical points with an uncertainty
of 2% in temperature and 3% in pressure. Graphical and statistical comparisons between experimental data and the available
thermodynamic models are discussed 相似文献
6.
Experimental results for the viscosity of squalane + CO2 mixtures are reported. The viscosities were measured using a rolling ball viscometer. The experimental temperatures were
293.15, 313.15, 333.15, and 353.15 K, and pressures were 10.0, 15.0, and 20.0 MPa. The CO2 mole fraction of the mixtures varied from 0 to 0.417. The experimental uncertainties in viscosity were estimated to be within
±3.0%. The viscosity of the mixtures decreased with an increase in the CO2 mole fraction. The experimental data were compared with predictions from the Grunberg–Nissan and McAllister equations, which
correlated the experimental data with maximum deviations of 10 and 8.7%, respectively. 相似文献
7.
Yen Hui Liu Min Chao Chang Hsin Shao Meng-Shun Huang Arnold Chang-Mou Yang 《Journal of Materials Science》2010,45(2):369-376
The anatase crystallization behaviors in ionothermal synthesis (sol–gel method containing ionic liquid) of nanostructured
TiO2 were studied in this paper. It was found that the specific physical chemical characteristics of the water/ionic liquid mixture
caused the formation path and crystallinity of anatase TiO2 to depend on the H2O/titanium dioxide precursor (titanium tetraisopropoxide, TIP) molar ratio. Hydroxylated titanium compound was a key intermediate
for forming anatase TiO2. It could be directly formed from hydrolysis of titanium dioxide precursor or ionic liquid-induced water dissolution of the
condensation product. X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA) data indicated that a higher
hydroxyl group ratio content of hydroxylated titanium compound was obtained at medium H2O/TIP molar ratio and from the system containing hydrophilic ionic liquid, such as 1-butyl-3-methylimidazolium tetrafluoroborate
([BuMIm]+[BF4]−). The self organization ability of ionic liquid drove anatase crystallization through dehydration of the Ti–OH group of hydroxylated
titanium compound in the thermal annealing process. As for the particle size of TiO2, TEM results indicated smaller particle size of TiO2 was obtained at medium H2O/TIP molar ratio case. 相似文献
8.
The filtration method was used to study the solubility of solid chlorine, hydrogen sulphide, sulphur dioxide, and ammonia in liquid nitrogen. SO2 and NH3 were found to be insoluble in LN2 at 77.4 K. The solubility of solid chlorine in LN2 changes over the range 2.13 × 10?7 mole fraction at 77.4 K to 0.57 × 10?7 mole fraction at 63.5 K. The solubility of solid hydrogen sulphide in LN2 changes within the range of 15.6 × 10?8 mole fraction at 77.4 K and 0.87 × 10?8 mole fraction at 63.5 K.The experimental results were compared with the solubilities calculated on the basis of the Scatchard-Hildebrand equation. 相似文献
9.
The interaction of alloys based on SmCo5 with hydrogen is studied by the methods of differential thermal and X-ray phase diffraction analyses under initial pressures
of hydrogen of 200, 300, 400, 500, and 650 kPa at temperatures of up to 1223°K. The hydride of the alloy is formed up to a
temperature of 343°K. Within the temperature ranges 388–408°K and 488–523°K, hydrogen is released from the hydrides of phases
of the alloy. Within the temperature range 823–863°K, the alloy partially disproportionates into Sm Hx and Co. At 1008–1053°K, SmHx undergoes partial decomposition and the SmCo5 and Sm2Co17 phases are detected. The Co, SmCo5, and Sm2Co17 phases exist at temperatures above 1168–1188°K. The compositions of the phases depend on the duration of interaction of the
alloy with hydrogen.
__________
Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 1, pp. 94–98, January–February, 2007. 相似文献
10.
Z. Nagamedianova E. Sánchez 《Journal of Materials Science: Materials in Electronics》2007,18(5):547-552
There is great interest in sulfide glasses because of their high lithium ion conductivity. New sulfide glasses based on Li2S-P2S5-Sb2S3 system have been synthesized by a classical quenching technique. A summary of thermal and structural characterization is
presented. Electrical conductivities of the samples have been determined by Impedance Spectroscopy. The compositions of low
lithium content (below 20% mol) have presented low electronic conductivities close to 10−8 S/cm at room temperature. The compositions of medium lithium content (30–50% mol) have presented mixed ionic-electronic behavior
with predominant on ionic conductivity with a maximum values around 10−6 S/cm for samples up to 50% Li2S at room temperature. Arrhenius behavior is verified between 25°C and Tg for all glasses with activation energies about 0.55–0.64 eV. A comparative study of conductivities with glasses belonging
to the other chalcogenide systems has been undertaken. 相似文献
11.
The reaction between magnesium and nickel powders in a KCl-NaCl-MgCl2 ionic melt at 970 K (reaction time, 5 h) has been studied by X-ray diffraction, scanning electron microscopy, energy dispersive
X-ray microanalysis, and chemical analysis. According to scanning electron microscopy data, the synthesized Mg2Ni powder consists of particles 70–75 nm in size, in reasonable agreement with the equivalent particle diameter, ≃ 64 nm,
determined from the specific surface area of the Mg2Ni powder and with the crystallite size, D
hkl
≃ 65 nm, evaluated from X-ray diffraction data. The hydrogen sorption properties of the Mg2Ni obtained in a KCl-NaCl-MgCl2 ionic melt are identical to those of Mg2Ni powder prepared by a standard method, but the former reacts with hydrogen far more rapidly. 相似文献
12.
D. M. Babanly 《Inorganic Materials》2011,47(6):583-587
The equilibrium subsolidus phase diagram of the TlBr-Tl2Se-TlSe system has been mapped out using X-ray diffraction analysis and emf measurements on thallium concentration cells.
Tl5Se2Br has been shown to have a broad homogeneity region. The emf results are used to evaluate the relative partial thermodynamic
functions of the thallium in the alloys studied and the standard integral thermodynamic functions (ΔG
0(298 K), ΔH
0(298 K), S
0(298 K)) of the Tl5Se2Br-based solid solutions. 相似文献
13.
M. B. Seregin A. P. Parshin A. Yu. Kuznetsov L. I. Ponomarev S. A. Mel’nikov A. A. Mikhalichenko A. A. Rzheutskii R. N. Manuilov 《Radiochemistry》2011,53(5):491-493
The solubility of UF4, ThF4, and CeF3 in fluoride melt of the composition 45 mol % LiF-12 mol % NaF-43 mol % KF in the temperature interval 773–973 K was determined.
The solubility of the fluorides increases with an increase in the melt temperature. The CeF3 solubility in the LiF-NaF-KF system is high: 19.9 mol % at 923 K and 23.3 mol % at 973 K. Experimental data on the solubility
of CeF3 (PuF3 imitator) were compared to the calculated data on the PuF3 solubility in the LiF-NaF-KF melt. The results showed that CeF3 can be considered as PuF3 imitator in FLINAK melt. 相似文献
14.
The effect of heating rate on the structural and magnetic properties of the nanocrystalline Fe81Si4B12P2Cu1 alloy has been investigated. Amorphous Fe81Si4B12P2Cu1 alloy was annealed at 753 K for 180 s at different heating rates ranging from 0.05 to 5 K/s in protective argon atmosphere.
The structural and magnetic properties of the as-quenched and annealed alloys were studied using X-ray diffractometer (XRD),
differential scanning calorimeter (DSC), vibrating sample magnetometer (VSM), and B–H loop tracer, respectively. Amorphous
precursor prepared by industry-grade raw materials is obtained. The increase of heating rate is found to be significantly
effective in decreasing the grain size of α-Fe(Si) phase, but the grain size increases at higher heating rate. The volume
fraction of α-Fe(Si) phase shows a monotonic decrease with the increase of the heating rate. The coercivity H
c markedly decreases with increasing heating rate and exhibits a minimum at the heating rate of 0.5 K/s, while the saturation
magnetization, M
s, shows a slight decrease. These results suggest that the effect of heating rate on H
c and M
s is originated from the changes of grain size and the volume fraction of α-Fe(Si) phase. 相似文献
15.
The viscosity of imidazolium-based ionic liquids with four different cations and three different anions was measured to pressures
of 126 MPa and at three temperatures (298.15 K, 323.15 K, and 343.15 K). The high-pressure viscosity of 1-ethyl-3-methylimidazolium
([EMIm]), 1-n-hexyl-3-methylimidazolium ([HMIm]), and 1-n-decyl-3-methylimidazolium ([DMIm]) cations with a common anion, bis(trifluoromethylsulfonyl)imide ([Tf2N]), was measured to determine the alkyl-chain length effect of the cation. An increase in the alkyl-chain length increased
the viscosity at elevated pressures. [DMIm] exhibited a larger nonlinear increase with pressure over the shorter alkyl substituents.
Anion effects were investigated with [HMIm] as a common cation and anions of [Tf2N], hexafluorophosphate ([PF6]), and tetrafluoroborate ([BF4]). [HMIm][PF6], with the highest viscosity, demonstrated a very nonlinear pressure dependence even at relatively moderate pressures (to
30 MPa), similar to the results for [BMIm][PF6]. A combined Litovitz and Tait equation was utilized to describe the viscosity of the ionic liquids with pressure and temperature
and demonstrated good correlation with the experimental data. 相似文献
16.
Xue Wang Chen Guo Hu Yi Xi Chuan Hui Xia Xiao Shan He 《Journal of Superconductivity and Novel Magnetism》2010,23(6):909-911
Al-doped Fe3O4 nanoparticles were synthesized for the first time via the Composite-Hydroxide-Mediated (CHM) method from Fe3O4 and Al2O3 without using any capping agent. The synthesis technique was one-step and cost effective. The obtained products were characterized
by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersion spectroscopy (EDS). Samples with a tunable
size of 500–1500 nm, 200–800 nm, and 100–700 nm could be obtained by adjusting the reaction time and temperature. Magnetic
property of the as-synthesized Al-doped Fe3O4 nanoparticles was investigated. Magnetic hysteresis loops measured in the field range of −10 kOe<H<10 kOe, indicated the ferromagnetic behavior with coercivity (H
c) of 470 and 110 Oe and remanence magnetization (M
r) of 13 and 6.4 emu/g at the temperature of 5 and 300 K, respectively. The saturation intensity (M
s) was 46.1 emu/g at 5 K, while it was about 43.6 emu/g at 300 K. 相似文献
17.
An experimental study of the pressure–volume–temperature-composition (pVTx) properties for the aqueous solution of ammonia, namely NH3–H2O mixtures, has been conducted with the use of a constant-volume apparatus, especially focusing on the maximum density behavior,
in the range of temperatures from 253 to 309 K, pressures from 0.47 to 16.93 MPa, densities from 950 to 1007 kg · m−3 and compositions from 0 to 0.1436 mole fraction of ammonia. The behavior of the maximum densities for the aqueous solution
of ammonia has been investigated for the first time by the present experimental study, and the available equations of state
do not represent the pVTx properties of the present measured data adequately near the maximum density region.
Paper presented at the Fifteenth Symposium on Thermophysical Properties, June 22–27, 2003, Boulder, Colorado, U.S.A. 相似文献
18.
The influence of doping with Ti and Al on the structure and hydrogen sorption properties of ZrFe2 was studied by XRD, XRSMA, and measurement of hydrogen absorption and desorption isotherms at pressure up to 300 MPa. The
hydrogen capacity and equilibrium desorption pressures of hydrides decrease with increasing Al content at a constant ratio
of Ti and Zr. The increase in the Ti content at a constant content of Al in alloys also leads to a decrease in hydrogen capacity;
however, the equilibrium desorption pressures of hydrides increase considerably. Zr1−x
Ti
x
(Fe1−y
Al
y
)2 (x= 0.2–0.8; y = 0.05–0.4) alloys were investigated. 相似文献
19.
YOSHIMI OHZAWA MITSUTAKA TAKAHASHI KOHZO SUGIYAMA 《Journal of Materials Science》1997,32(16):4289-4294
SiC was infiltrated in two-dimensionally woven Tyranno/SiC particulate preforms from SiCl4–CH4–H2 using pressure-pulsed chemical vapour infiltration (PCVI) in the temperature range 1348–1423 K. Above 1373 K, only β-SiC
was deposited, whereas, at 1348 K, Si codeposition was found. At 1423 K, a macrosurface film was formed in the early stage
of PCVI. At 1373 K, residual porosity decreased from 30% to 7.5% irrespective of the sample size. Three point flexural strength
increased with decreasing residual porosity and increasing fibre volume fraction in the sample. Flexural strength of the sample
having 48% fibre volume fraction reached about 325 MPa after 5 × 104 pulses of CVI at 1373 K. Inter-laminar shear strength of the sample obtained at 1373 K reached 40 MPa at 7 × 104 pulses.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
20.
Passynski’s hydration numbers were calculated for 1-propanol, 2-methylpyridine, 3-methylpyridine, 4-methylpyridine, 2,6-dimethylpyridine,
and 2,4, 6-trimethylpyridine in H2O and D2O, for the temperature range from 277K to 313 K. Correlations between the hydration numbers and the association energies of
1:1 water–amine complexes as well as the net atomic charges on the nitrogen atom were found. It seems probable that the O–H·
· ·N bond promotes the structure due to the strengthening of the O–H· · ·O bonds between water molecules neighboring that
of amine. The higher the O–H· · ·N bond energy, the stronger is the promoting effect. The calculated hydration numbers in
H2O are lower than their counterparts in D2O. ThusD2O appears more sensitive than H2O to the solute-induced changes of structure. 相似文献