Magnetic and structural properties of CaO–SiO2–P2O5–Na2O–Fe2O3 glass ceramics

Magnetic properties of glass ceramics derived from glasses with composition 41CaO·(52−x)SiO₂·4P₂O₅·xFe₂O₃·3Na₂O (2?x?10 mol% iron oxide (Fe₂O₃)) are reported. Structural investigation revealed the presence of nanocrystalline magnetite phase in the heat-treated samples containing x?2 mol% Fe₂O₃. Magnetic hysteresis cycles of the glass-ceramic samples were obtained with a maximum applied field of ±20 kOe as well as a low field of ±500 Oe, in order to evaluate the potential of these glass ceramics for hyperthermia treatment of cancer. Samples with x>2 mol% of iron oxide exhibited magnetic behavior similar to soft magnetic materials with low coercivity. The evolution of magnetic properties in these samples as a function of iron oxide molar concentration is correlated with the amount and crystallite size of magnetite phase present in them.     

Investigation of structural,physical and optical properties of CeO2–Bi2O3–B2O3 glasses

xCeO₂–30Bi₂O₃–(70−x) B₂O₃ glasses are synthesized by using the melt quench technique. A number of studies such as XRD, density, molar volume, optical band gap, refractive index and FTIR spectroscopy are employed to characterize the glasses. The band gap decreases from 2.15 to 1.61 eV, refractive index increases from 2.67 to 2.93 and density increases from 4.151 to 4.633 g/cm³. The decrease in band gap with CeO₂ doping approaches the semiconductor behavior. FTIR spectroscopy reveals that incorporation of CeO₂ into glass network helps to convert the structural units of [BO₃] into [BO₄] and results in Bi–O bond vibration of [BiO₆].     

Physical,optical and radiative properties of CaSO4–B2O3–P2O5 glasses doped with Sm3+ ions

Trivalent rare earth ions doped borosulfophosphate glasses are in high demand owing to their several unique attributes that are advantageous for applications in diverse photonic devices. Thus, Sm³⁺ ion doped calcium sulfoborophosphate glasses with composition of 25CaSO₄–30B₂O₃–(45?x)P₂O₅–xSm₂O₃ (where x?=?0.1, 0.3, 0.5, 0.7 and 1.0 mol%) were synthesized using melt-quenching technique. X-ray diffraction confirmed the amorphous nature of the prepared glass samples. Differential thermal analyses show transition peaks for melting temperature, glass transition and crystallization temperature. The glass stability is found in the range 91?°C to 116?°C which shows increased stability with addition of Sm₂O₃ concentration. The Fourier transform infrared spectral measurements carried out showed the presence of vibration bands due to PO linkage, BO_3, BO₄, PO₄, POP, OPO, SOB, and BOB unit. Glass density showed increase in value from 2.179 to 2.251?g cm^?3 with increase in Sm₂O₃ concentration. The direct, indirect band gap and Urbach energy calculated were found to be within 4.368–4.184?eV, 3.641–3.488?eV and 0.323–0.282?eV energy ranges, respectively. The absorption spectra revealed ten prominent peaks centered at 365, 400, 471, 941, 1075, 1228, 1375, 1477, 1528 and 1597?nm corresponding to ⁴D_3/2,⁶H_5/2→⁴I_11/2,⁶P_3/2, ⁶F_11/2, ⁶F_9/2, ⁶F_7/2, ⁶F_5/2, ⁶F_3/2, ⁶H_15/2 and ⁶F_1/2 transitions respectively. Photoluminescence spectra monitored at the excitation of 398?nm exhibits four emission bands positioned at 559, 596,643 and 709?nm corresponding to ⁴G_5/2→⁶H_5/2, ⁶H_7/2, ⁶H_9/2 and ⁶H_11/2 transitions respectively. The nephelauxetic parameters calculated showed good influence on the local environment within the samarium ions site and the state of the SmO bond. The Judd–Ofelt intensity parameters calculated for all glass samples revealed that Ω_6?>?Ω_4?>?Ω₂. The emission cross-section and the branching ratios values obtained for ⁴G_5/2→⁶H_7/2 transition indicate its suitability for LEDs and solid-state laser application.     

Preparation and characteristics of?a?BaO–Al2O3–B2O3–SiO2–La2O3 glass ceramic via spray pyrolysis

The characteristics of a BaO–Al₂O₃–B₂O₃–SiO₂–La₂O₃ glass ceramic prepared by spray pyrolysis were studied. Glass powders with spherical shape and amorphous phase were prepared by complete melting at a preparation temperature of 1 500°C. The mean size and geometric standard deviation of the powders prepared at the temperature of 1 500°C were 0.6 μm and 1.3. The glass powders had similar composition to that of the spray solution. The glass transition temperature (T _g) of the glass powders was 600.3°C. Two crystallization exothermic peaks were observed at 769.3 and 837.8°C. Densification of the specimen started at a sintering temperature of 600°C, in which Ba₄La₆O(SiO₄)₆ as main crystal structure was observed. Complete densification of the specimen occurred at a sintering temperature of 800°C. The specimens sintered at temperatures above 800°C had main crystal structure of BaAl₂Si₂O₈.     

Varistor and dielectric properties of Cr2O3 doped SnO2–Zn2SnO4 composite ceramics

Cr₂O₃ doped SnO₂–Zn₂SnO₄ composite ceramics were prepared by traditional ceramic processing and the varistor, dielectric properties were investigated. With increasing Cr₂O₃ content, the breakdown electrical field E_B increases from 11 to 92 V/mm and the relative dielectric constant ε_r measured at 1 kHz, 50 °C decreases from 11,028 to 3412, respectively. The barrier height ?_B about 0.8–0.84 eV and the decreasing of SnO₂ grain size suggest that the varistor behavior with high ε_r is originated from SnO₂–SnO₂ or SnO₂–Zn₂SnO₄ grain boundary. In the dielectric spectra lower than 1 kHz, a dielectric peak is presented and depressed with increasing bias voltage. Similarly, at high temperature, the dielectric constant also presents a dielectric peak in the temperature spectra and the peak becomes faint with increasing frequency. The exhibition of the dielectric peak is thought to be attributed to the conduction of grain boundary since it is accompanied by the sharp increase of dielectric loss. In addition, a dielectric relaxation with the activation energy about 0.4–0.5 eV was observed in the temperature range of 20–100 °C. Based on the results, the formation mechanism of Schottky barriers at grain boundaries and the varistor behavior with high dielectric constant are well understood.     

FTIR Study of the ν1/ν4 Bands of D3SiCl near 1600 cm

The ν₁ (A₁, 1583.22 cm⁻¹) and ν₄ (E, 1615.33 cm⁻¹) Si-D stretching bands of monoisotopic D₃Si³⁵Cl have been studied by FTIR spectroscopy with a resolution of 3.3×10⁻³ cm⁻¹. We have assigned 2341 rovibrational lines for ν₁ (J_max=70, K_max=19) and 6207 for ν₄ (J_max=75, K_max=27). Both (ΔK=±1, Δ?=±1) and (ΔK=±2, Δ?=?1) interactions connect the v₁=1 and v₄=1 levels, the latter exerting moreover a weak ?(2, 2) interaction. These interactions were taken into account in a nonlinear least-squares fit, refining 29 free parameters with a standard deviation of 0.257×10⁻³ cm⁻¹ over 6722 nonzero-weighted data. Blended lines and about 250 of the 330 lines belonging to the K=11 subband of ν₁ and the KΔK=−6 subband of ν₄ were zero-weighted because they are locally perturbed respectively by the neighboring upper states of the 2ν₃+ν₆ (E, 1561.95 cm⁻¹) and 3ν₃ (A₁, 1604.81 cm⁻¹) bands. Equivalent fits were obtained for altogether three different models obeying constraints according to the theory of unitary equivalent reductions of the rovibrational Hamiltonian. By means of a band contour simulation both the transition moment ratio |M₁:M₄|=0.67 and a positive sign of the Coriolis intensity perturbation were determined.     

Electrodeposition of TiO2–RuO2–IrO2 coating on titanium substrate

TiO₂, RuO₂, and IrO₂ transition metal oxides have many applications in the field of applied electrochemistry. In this work, the mixed solid solutions of TiO₂–RuO₂–IrO₂ coatings have been electrodeposited from aqueous–unaqueous baths.     

D+CD4→CD3+D2反应的四维量子散射计算

运用约化维数量子动力学理论，利用含时波包法，对反应D+CD₄→CD_{3+D2进行了四维量子散射计算.将反应多原子CD4看作双原子D—CD 3，反应D+CD4→CD3+D2看作单原子-双原 子反应，把体系的反应简化为四维散射问题. 波函数的传播采用分裂算符法，为避免格点边界处含时波函数的边界反射，采用了光学吸收 势法，在格点边界处引入光学势，消除边界反射.根据CD4分子的C3v对称性， 选取了Jordan和Gilbert提出的半经验势能面.计算结果表明，反应概率随平动能的变化图像 ，呈现出显著的量子共振特性，这是很多提取反应的共同特征.而不同振动态下的反应概率 随平动能的变化表明，随振动量子数的增大，反应概率有明显提高，且反应阈能明显降低， 这说明反应分子的振动能对分子的碰撞反应有重要贡献.而对基态和第一振动激发态时散射 截面的计算，也证明了这一结论.同时，还分别通过计算量子数j，k，m对反应概率的影响， 对该反应的空间取向效应进行了研究，并与H+CH4→CH3+H2反应进行了比较. 关键词： 含时波包 量子散射 反应概率}     

FTIR structural investigation of gamma irradiated BaO–Na2O–B2O3–SiO2 glasses

Fourier transform infrared (FT-IR) spectra of xBaO–15Na₂O–(70−x)B₂O₃–15SiO₂ glass system with x=0, 5, 10, 15 and 20 (mol%) has been measured in the spectral range 400–4000 cm⁻¹ at room temperature in order to understand the characteristic frequencies of the chemical bonds and bonding mechanisms, which are susceptible to the structural and spectral changes. The effect of gamma irradiation in the dose range 0.1 kGy–60 kGy on the infrared absorption spectra of these glasses is also reported. The change in the glass structure due to the effect of composition is also discussed. It has been observed that irradiation of the glasses with the gamma rays increases the BO₃ groups and the non bridging oxygens which make the network loose.     

Effects of BaCu（B2O5 ） addition on sintering temperature and microwave dielectric properties of Ba5Nb4O15–BaWO4 ceramics

The effects of BaCu(B2O5)(BCB) addition on the microstructure, phase formation, and microwave dielectric properties of Ba5Nb4O15–BaWO4ceramic are investigated. As a sintering aid, BaCu(B2O5) ceramic could effectively lower the sintering temperature of Ba5Nb4O15–BaWO4ceramic from 1100?C to 950?C due to the liquid-phase effect. Meanwhile,BaCu(B2O5) addition effectively improves the densification of Ba5Nb4O15–BaWO4ceramic and significantly influences the microwave dielectric properties. X-ray diffraction analysis reveals that Ba5Nb4O15and BaWO4coexist with no crystal phase of BaCu(B2O5) in the sintered ceramics. The Ba5Nb4O15–BaWO4ceramics with 1.0 wt% BaCu(B2O5) sintered at 950?C for 2 h presents good microwave dielectric properties of εr = 19.0, high Q × f of 33802 GHz and low τfof2.5 ppm/?C.     

Magnetic field dependence of piezoelectric resonance frequency in CoFe2O4–BaTiO3 composites

The particulate and the multilayer CoFe₂O₄(CFO)–BaTiO₃(BT) composites were prepared by the conventional solid state reaction method and the tape casting method, respectively. Both the prepared composites were simultaneously ferroelectric and ferromagnetic at room temperature. For the multilayer composite sample, a piezoelectric resonance frequency remarkably depended on the applied DC magnetic field, while no remarkable magnetic field dependence was observed for the particulate composite samples. An uniform magnetostriction of the CFO phase in the multilayer composite contributes to piezoelectric effect of the BT phases, resulting in the modulation of the piezoelectric resonance frequency.     

The 2ν4 overtone bands of FClO3

The high resolution infrared spectrum of the mono-isotopic species F³⁵Cl¹⁶O₃ has been studied in the region of the 2ν₄ overtone, from 2560 to 2680 cm⁻¹. The perpendicular component is strong and clearly observed while the parallel component is very weak and almost completely hidden by the perpendicular one. Their origins differ by 12.6 cm⁻¹, the being located at higher wavenumbers. The band is perturbed by the anharmonic interaction between the v₄ = 2, l₄ = ?2 and v₂ = v₄ = v₅ = 1, l₄ = l₅ = ±1 excited states, both of E symmetry. In total 3157 transitions have been assigned, 83% of these to , 12% to , and 5% to . The three bands have been analyzed simultaneously, taking into account the Fermi resonance effective between the excited states of E symmetry. The ro-vibration parameters of the excited states have been obtained, including the deperturbed band origins of and , at 2628.5890(4) and 2619.3342(5) cm⁻¹, respectively. The W₂₄₅ anharmonic constant is equal to 4.0161(4) cm⁻¹. The x₄₄+g₄₄ and x₂₄+x₄₅+g₄₅ anharmonicity constants have been derived from the obtained band origins and those of ν₄ and ν₂ + ν₅.     

D3→FJ emission of Tb doped sol–gel silica

Amorphous silica samples doped with 0.1 and 1 mol% of terbium (Tb) were synthesized by the sol–gel method. In addition to the green light associated with ⁵D₄→⁷F_J transitions of Tb³⁺, the sample containing 0.1 mol% also emitted blue light as a result of ⁵D₃→⁷F_J transitions during photoluminescence (PL) measurements. As a result of concentration quenching this blue emission was not observed for the samples doped with the higher concentration (1 mol%). However the blue ⁵D₃ →⁷F_J emission was observed in the 1 mol% doped samples during cathodoluminescence (CL) measurements. Since a rough calculation indicated that the excitation rate in the CL system where the blue emission is observed may be similar to a laser PL system under conditions where the blue emission is not observed, the difference is attributed to the nature of the excitation sources. It is suggested that during the CL excitation incident electrons can reduce non-luminescent Tb⁴⁺ ions in the silica, substituting for Si⁴⁺ ions, to the excited (Tb³⁺)? state and that these are responsible for the blue emission, which does not occur during PL excitation.     

High-Resolution Fourier-Transform Intracavity Laser Absorption Spectroscopy of D2O in the Region of the 4ν1+ν3 Band

The high-resolution absorption spectrum of the D₂O molecule was recorded with the Fourier-transform intracavity laser absorption spectrometer in the region 12 570-12 820 cm⁻¹ where the band 4ν₁+ν₃ is located. Transitions belonging to the 4ν₁+ν₃ band, and the bands 3ν₁+2ν₃ and 3ν₁+2ν₂+ν₃, of which the up states are strongly interacted with that of the 4ν₁+ν₃, were assigned in the recorded spectrum. Up state energy levels were fitted to derive effective spectroscopic parameters, which reproduce majority of the assigned transitions within the experimental accuracy.     

Vibration-Torsion-Rotation Study of the ν5 State of CH3CF3

An investigation of the torsion-rotation-vibration energies in the ν₅ vibrational state in CH₃CF₃ has been carried out using infrared and mm-wave spectroscopy. The lowest frequency parallel fundamental band ν₅ near 600 cm⁻¹ has been measured at a resolution of 0.00125 cm⁻¹ with Fourier transform spectroscopy for the two lowest torsional states v₆=0 and 1. The cold band (v₅=1, v₆=0)←(v₅=0, v₆=0) showed no torsional splittings and looked much like a parallel band in a C_3v molecule. The hot band (v₅=1, v₆=1)←(v₅=0, v₆=1) consisted of three distinct subbands, one for each torsional sublevel σ=0, +1, and −1. For the state (v₅=1, v₆=1), the torsional splitting was increased from ∼0.001 cm⁻¹ to ∼0.022 cm⁻¹ by torsion-mediated Fermi-type interaction primarily with the dark state (v₅=0, v₆=5). The effects of this coupling on the spectrum are striking in spite of the fact that the two interacting states are ∼100 cm⁻¹ apart and differ by four units in v₆. The large amplitude character of the state (v₅=0, v₆=5) is seen to be largely responsible for the unusual (k, σ) dependence of the energies in the state (v₅=1, v₆=1). The pure rotational spectrum in the state (v₅=1, v₆=0) has been measured between ∼50 and 370 GHz with Doppler-limited resolution; no σ-splitting was detected. The 3590 infrared and mm-wave frequencies measured here have been analyzed together with the 1494 measurements reported earlier by Wang et al. in an analysis of the vibrational ground state (2001, J. Mol. Spectrosc.205, 146-163). A good fit was obtained here by varying 36 parameters in a Hamiltonian which takes into account the interaction between the torsional stacks of levels for v₅=0 and 1, as well as the (A₁−A₂) splittings measured earlier for v₅=0. The explicit treatment of the interstack interactions is shown to lead to significant changes in the parameters (V_0,3, V_0,6) that characterize the torsional potential for v₅=0. These changes have been explained quantitatively by examining the contact transformation that is implicitly applied when the interstack coupling is neglected.     

Li2K(IO3)3与Li2NH4(IO3)3的晶体结构

本文用X射线粉末法测定了Li₂K(IO₃)₃与Li₂NH₄(IO₃)₃的晶体结构和原子参数。发现Li₃K(IO₃)₃,Li₂NH₄(IO₃)₃与Li₂Rb(IO₃)₃同晶型,属单斜晶系,空间群为P2₁/α,每个单胞含有四个化合式量。室温的点阵常数分别为α=11.198?,b=11.046?,c=8.254?,β=111.53°,及α=11.327?,b=11.078?,c=8.341?,β=111.87°。讨论了二元化合物的形成与离子半径的关系。 关键词：     

The (ν1, ν4, ν2+ν3, ν3+ν5) Polyad of D3SiF around 1600 cm, Studied by High-Resolution FTIR Spectroscopy

The ν₁ (A₁, 1578.31 cm⁻¹)/ν₄(E, 1615.17 cm⁻¹) Si-D stretching dyad of D₃SiF has been studied by FTIR spectroscopy with a resolution of 2.4×10⁻³ cm⁻¹. Only weak interactions of Coriolis (ΔK=±1, Δ?=±1) and α resonance (ΔK=±2, Δ?=?1) type between ν₁ and ν₄, and of ? (2,−4) type within ν₄, were revealed. However, the v₁=1 and v₄=1 levels were found to be severely perturbed by the v₃=v₅=1 (E, 1590.37 cm⁻¹) and v₂=v₃=1 (A₁, 1604.25 cm⁻¹) states. These perturbations are observable only near level crossings involving strong Coriolis and α interactions. The energy structure within these perturbers is severely complicated by strong Coriolis and α resonances and by ? (2, 2), ? (2,−1), and ? (2,−4) interactions as already revealed by the ν₂(A₁, 710.16 cm⁻¹) and ν₅ (E, 701.72 cm⁻¹) fundamentals. Interactions of the perturbing states with the ν₁/ν₄ dyad are particularly evident in local crossings. In total, 12 transitions belonging to the dark states and 68 perturbation-allowed transitions within the ν₁/ν₄ dyad have been detected among the more than 5000 transitions that have been assigned for the ν₁/ν₄ dyad, with J_max and K_max of 50 and 30, respectively. Altogether about 85% of the assigned transitions were fitted with a standard deviation of 0.221×10⁻³ cm⁻¹, leading to 61 parameters of the interacting polyad.     

Flat Band and Z2 Topology of Kagome Metal CsTi3Bi5

The simple kagome-lattice band structure possesses Dirac cones, flat band, and saddle point with van Hove singularities in the electronic density of states, facilitating the emergence of various electronic orders. Here we report a titanium-based kagome metal CsTi₃Bi₅ where titanium atoms form a kagome network, resembling its isostructural compound CsV₃Sb₅. Thermodynamic properties including the magnetization, resistance, and heat capacity reveal the co...     

(NH4)2SO4，NH4NO3和(NH4)2SO4/NH4NO3混合气溶胶吸湿质量增长因子的快速测量方法

气溶胶颗粒的吸湿性决定了其尺寸、浓度、化学组成以及相态,从而显著影响着全球气候、大气异相化学以及人类健康。运用在线、原位、连续扫描衰减全反射傅里叶变换红外光谱（ATR-FTIR）技术, 结合线性湿度（RH）控制系统,实现了RH连续变化条件下气溶胶FTIR-ATR光谱的快速测量。根据水弯曲振动谱带（~1 640 cm-1）峰面积随RH的变化,得到了(NH₄)₂SO₄,NH₄NO₃和(NH₄)₂SO₄/NH₄NO₃混合气溶胶的质量增长因子（MGFs）、潮解点（DRH）和风化点（ERH）。与气溶胶的E-AIM模型预测值相比较,实验结果表现出良好的一致性,证实该方法是一种测量大气气溶胶MGFs,ERH和DRH的快速测量方法。