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1.
本文对类镓等电子序列GaI-XeXXIV离子4s^24p、4s^24p、4s^24d、4s4p^2、4p^3和4s^25s组态组级结果和组态相互作用了理论分析,找出沿等电子序列的变化规律。 相似文献
2.
The vortex pinning determining the current carrying capacity of a superconductor is an important property to the applications of superconducting materials.For layered superconductors,the vortex pinning can be enhanced by a strong interlayer interaction in accompany with a suppression of superconducting anisotropy,which remains to be investigated in iron based superconductors(FeSCs)with the layered structure.Here,based on the transport and magnetic torque measurements,we experimentally investigate the vortex pinning in two bilayer FeSCs,CaKFe 4As 4(Fe1144)and KCa 2Fe 4As4F 2(Fe12442),and compare their superconducting anisotropyγ.While the anisotropyγ≈3 for Fe1144 is much smaller thanγ≈15 in Fe12442 around Tc,a higher flux pinning energy as evidenced by a higher critical current density is found in Fe1144,as compared with the case of Fe12442.In combination with the literature data of Ba 0.72K 0.28Fe2As 2 and Nd Fe As O0.82F 0.18,we reveal an anti-correlation between the pinning energy and the superconducting anisotropy in these Fe SCs.Our results thus suggest that the interlayer interaction can not be neglected when considering the vortex pinning in Fe SCs. 相似文献
3.
The cation order-disorder transitions in Ag 2HgI 4 and Cu 2HgI 4 are first order. This is unusual, since in other superionic conductors the cation disordering is gradual with temperature if there is no structural phase transition. These two materials are also unique in that they have two disordering cations rather than one. A study of a two species lattice gas model shows that this extra degree of freedom is responsible for the first order nature of this transition on the fcc lattice. 相似文献
4.
利用成熟的偏振控制技术,设计了一种由偏振光分束器、相位型空间光调制器和反射镜构成的2×2光开关,该光开关所用器件少,具有结构简单紧凑、控制灵活方便、功能实现与信号光的偏振态无关以及可以双向交换等特点;在此基础上通过2×2光开关的串连,设计了一种与偏振无关的双向4×4光开关的实验模块,根据其路由选择与控制方法,得到了4×4光开关实现信号光全排列无阻塞输出与交换对应的路由状态表,并对该实验模块的功能实现进行了详细的分析与讨论。 相似文献
6.
The time-differential perturbed angular correlation technique has been used to study the temperature dependence of the electric-field gradient at 111Cd nuclei in the spinels CdFe2O4 and ZnFe2O4. The samples were doped with radioactive 111In tracers which decay to 111Cd by electron capture. For both compounds the results of the measurements show the presence of two electric quadrupole interactions. One is well defined and corresponds to a fairly symmetrical electric field gradient. The other is broadly distributed and corresponds to electric field gradients with lower symmetry. The fractions of probes associated with these interactions are temperature dependent. The interactions are analysed taking into account the possible sites in the spinel structure for In occupation. The results are compared with those obtained with other spinels. The electric field gradient associated with the octahedral site is compared with the predictions of point charge model and with Mössbauer spectroscopy results at iron site. 相似文献
7.
The aim of this study was to prepare a novel targeting nano drug delivery system of 2-methoxyestradiol (2-ME) based on the folic acid-modified bovine serum albumin, in order to improve the clinical application disadvantages and antitumor effect of 2-ME. In this study, 2-methoxyestradiol-loaded albumin nanoparticles (2-ME-BSANPs) were prepared by desolvation method, and then the activated folic acid was conjugated to 2-ME-BSANPs by covalent attachment (2-ME-FA-BSANPs). The size and zeta potential of 2-ME-FA-BSANPs were about 208.8 ± 5.1 nm and ?32.70 ± 1.01 mV, respectively. 2-ME loading efficiency and loading amount of the nanoparticles were 80.49 ± 3.80 and 10.25 ± 1.59 %, respectively. SEM images indicated that 2-ME-FA-BSANPs were of a round shape, similar uniform size, and smooth surface. Studies on drug release indicated that 2-ME-FA-BSANPs had the properties of sustained and controlled release, which provided them with the ability to fight continually against cancer cells. Internalization analysis demonstrated that 2-ME-FA-BSANPs-targeting drug delivery system could get efficiently transferred into the cells through the folic acid-mediated endocytosis, leading to higher apoptosis and affording higher antitumor efficacy against SMMC-7721 cells in vitro compared with 2-ME alone. Furthermore, the cell-cycle arrest of 2-ME-FA-BSANPs on the SMMC-7721 cells occurred at G2/M phase, and 2-ME-FA-BSANPs did not change the inhibition of the tumor mechanisms of 2-ME. Based on these results, it was concluded that albumin nanoparticles could be the promising nano carrier for 2-ME, and 2-ME-FA-BSANPs-targeting drug delivery system may be promising candidate for providing high treatment efficacy with minimal side effects in future cancer therapy. 相似文献
8.
Thermal, physical, structural, optical, and dielectric investigations have been performed for oxyfluoride solid solutions (NH 4) 2W 1 — x Mo x O 2F 4 ( x = 0, 0.1, 0.2, 0.3, 0.4, 0.6, 0.8, 1). The character of the influence of the chemical and hydrostatic pressures on the stability of the parent (space group Cmcm) and distorted ferroelastic and antiferroelectric phases has been determined by analyzing the temperature-pressure, unit cell volume-composition, and temperature-composition phase diagrams. The specific features of the nature and mechanism of the phase transitions have been discussed using the available data on the structural, entropy, and dielectric parameters. 相似文献
9.
Infrared reflection spectra of single crystals of BeSO 4·4H 2O and BeSO 4·4D 2O have been obtained in polarized light at 300°K and at 14°K in the region between 4000 cm ?1 and 300 cm ?1. By a Kronig-Kramers analysis, the frequencies of the infrared active transitions have been calculated. These transitions are attributed to internal vibrations of the water molecules and sulfate ions and, in the region between 1000 cm ?1 and 300 cm ?1, especially to internal and external vibrations of the tetrahedral Be ++·4aqu-complexes. The vibrational modes of these complexes consist of a superposition of translational and librational modes of the water molecules and translational modes of the central Be ++-ion. The vibrational frequencies and normal modes of this complex have been calculated in a central-force model, and force-constants have been determined by fitting the calculated frequencies to the observed spectra. The calculations have shown that the modes, which comprise mainly translational motions of the water molecules, are strongly coupled with librational motions of the water molecules. On the other hand, there exist pure librational modes with practically no admixture of translational motions. The optimum sets of force constants for the BeSO 4·4H 2O crystal and the BeSO 4·4D 2O crystal differ in a manner which can be understood under the assumption that the dimensions of the Be(D 2O) 4 complex are about 0.1 Å larger than those of the Be(H 2O) 4 complex. Some arguments supporting this conclusion will be discussed. 相似文献
14.
Ferrites with the composition Mg 1−x
CO
x
Fe 2O 4(0< x≤0·33) were synthesized by solid state reaction between MgO, α-Fe 2O 3 and CoFe 2O 4 at 1300°C. The compounds were analyzed from the results of x-ray diffraction, magnetic hysteresis and initial susceptibility
( χ) studies. All the compounds of the series were found to be monophasic with no appreciable change in their lattice parameter.
The saturation magnetization and coercive field ( H
c
) values increased with increasing cobalt ferrite content. Similarly, the shapes of the χ-T curves and temperature variations of H
c
values indicated that the magnetic behaviour changes from multi-domain to single domain with increasing cobalt content. The
results are similar to those observed for the (MgFe 2O 4) 1−x
(Co 3O 4) system. 相似文献
15.
Optics and Spectroscopy - The frequencies and intensities are calculated for fundamental transitions between vibrational states of an electride-like molecule Li4C4H2N2 that can be obtained from the... 相似文献
16.
(NH 4) 2WO 2F 4 single crystals are grown, and their polarization-optical, calorimetric, and birefringence properties are studied in the
temperature range 90–350 K. A first-order structural phase transition is found to occur at T
01↑ = 202 K with thermal hysteresis of Δ T
01 ≈ 6–12 K. The phase transition is accompanied by twinning and modification of the symmetry
. An additional weak anomaly in the differential scanning calorimeter signal is found at T
02 ≈ 170 K. The total thermal effect of both anomalies is ∑Δ H
i = 3200 ± 400 J/mol and ∑Δ S
i = 16.5 ± 2.0 J/mol K. The phase transition at T
01 is of the order-disorder type. 相似文献
17.
Tungsten–bronze polycrystalline ceramic Li 2Pb 2Dy 2W 2Ti 4V 4O 30 was prepared by mixed-oxide method. The preparation conditions were optimized by thermogravimetry analysis and repeated firing. Room-temperature structural analysis confirms the formation of the compound in single phase (orthorhombic). Studies of dielectric parameters ( ) of the compound with temperature at different frequencies suggest the existence of phase transition in the compound. The existence of ferroelectric property (based on dielectric anomaly) of the material was confirmed by polarization study. 相似文献
19.
The electron paramagnetic resonance (EPR) spectrum of Cr 5+(3 d
1, S=1/2) in undeuterated and 58%-deuterated NH 4H 2AsO 4 was investigated. The EPR g-value tensors in the paraelectric and antiferroelectric phases are almost the same as those observed at high and low temperatures in KH 2PO 4 and KH 2AsO 4. This shows that the (Cr 5+O 4)H 2 complex is the same in all crystals, i.e., a wave function of d
x
2– y
2 character coupled to two lateral protons which reorient among the four possible Slater configurations in the paraelectric phase. The remarkable isotope shift of the local dynamic reorientational slowing-down observed in KH 2PO 4 and KH 2AsO 4 in approximate proportion to the shift of the bulk ferroelectric transition temperatures T
c
F
, and the antiferroelectric T
c
AF
of NH 4H 2AsO 4, is analyzed qualitatively. It is shown to result mainly from the isotope effect of the short-range interaction J
sr
via protons and deuterons for the impurity and for the bulk.
Q-band data of the (Cr 5+O 4)H 2 center in 75%-deuterated KH 2AsO 4 are also reported. An averaged high- and nonaveraged low-temperature EPR spectrum is observed in a temperature range of 250 to 290 K. The intensity ratio of the two follows an exp 2( T—T)/ law over four orders of magnitude at T=266 to 273 K and =5.3 to 6.1 K depending on the orientation of the external magnetic field. This novel result in motional narrowing is analyzed analytically to be compatible with a distribution P
A
of
0( T, T, ) of half width , in reorientation times
with E=0.23 ±0.02 eV,
, probably resulting from the statistical occupation of deuterium atoms among the O—–H–O bridges. Comparison with a theory of Binder definitely proves the extrinsic slowing-down and thus Halperin-Varma type character. In the range of temperatures investigated no local freeze-out has been detected. 相似文献
20.
(NH 4) 2MoO 2F 4 single crystals were grown and studied using polarization-optical methods, and the birefringence was measured in the temperature range 90–350 K. The following sequence of phase transitions is revealed: G 0 ? G 1 ? G 2. It is established that the phase transition at T 01 ≈ 267 K is of the first order and exhibits thermal hysteresis δ T 01 ≈ 0.6 K. A weak anomaly is found in Δ n( T) at T 02 ≈ 180 K. The crystals are shown to retain the orthorhombic symmetry during the phase transitions. 相似文献
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