Magnetic properties of ferrites-cobaltites Bi1 − x La x Fe1 − x Co x O3 (1.0 ≥ x ≥ 0.7) with a perovskite structure

The molar magnetic susceptibility (χ_mol) of Bi_{1 ? x} La _x Fe_{1 ? x} Co _x O₃ solid solutions (x = 1.0, 0.9, 0.8, or 0.7) with a crystal structure of rhombohedrally distorted perovskite (R $\bar 3$ c) has been investigated in the temperature range of 5–300 K in a 0.86 T magnetic field. In the temperature range where χ_mol depends on temperature T according to the Curie-Weiss law, the resulting effective magnetic moments of Fe³⁺ and Co³⁺ ions ( $\mu _{eff,Fe^{3 + } ,Co^{3 + } ,} \mu _{eff,Fe^{3 + } } $ and $\mu _{eff,Co^{3 + } } $ ) have been determined for the solid solutions under study. Fe³⁺ ions in the solid solutions have been found to be in the mixed intermediate spin (IS) and high spin (HS) states ( $\mu _{eff,Fe^{3 + } } $ is 4.26μ_B and 4.68μ_B for the temperature range of 5–100 and 150–300 K, respectively). It is shown that 8% Co³⁺ ions in LaCoO₃ at 5–19 K are in the paramagnetic IS state and they determine to a great extent the magnetic susceptibility. It is established that only 9% and 18% Co³⁺ ions in Bi_{1 ? x} La _x Fe_{1 ? x} Co _x O₃ solid solutions (x = 0.9 or 0.8) are in the paramagnetic IS state in the temperature ranges of 5–30 and 5–110 K, respectively, while the other ions are diamagnetic.     

Crystal structure,magnetic and electric properties of highly coercive ferrites Sr1 − x Sm x Fe12 − x Zn x O19 (0 ≤ x ≤ 0.4)

The samples of highly coercive ferrites Sr_{1 ? x} Sm _x Fe_{12 ? x} Zn _x O₁₉ (0 ≤ x ≤ 0.4) with the structure of magnetoplumbite have been obtained by the solid-phase method. It has been determined that the samples Sr_{1 ? x} Sm _x Fe_{12 ? x} Zn _x O₁₉ are single-phase at x ≤ 0.2 and contain the impurity phases of α-Fe₂O₃, SmFeO₃, and ZnFe₂O₄ at x ≥ 0.3. In the magnetic fields up to 14 T, the specific magnetization has been measured and the values of coercive force (_σ H _c ) have been determined at 5 and 300 K. It has been shown that semiconductor electroconductivity of single-phase samples Sr_{1 ? x} Sm _x Fe_{12 ? x} Zn _x O₁₉ gradually decreases with the increase in the degree of substitution of x from 0 to 0.2.     

Characterization of the Li1−x H x AlO2 system; 0.00 ⩽x ⩽ 0.90

The mechanism of cation replacement in the Li_1–x H _x AlO₂; 0.00 x 0.90 system was investigated with XRD. Examination of the peak position and intensity associated with the 018 and 110 Bragg reflections in a series of partially replaced samples showed that the cation replacement process proceeded by a two phase mechanism. Catalytic characterization of LiAlO₂ with the 2-propanol probe reaction revealed the formation of the condensation products methyl-cyclopentene, 4-methyl-2-pentanone, and 4-methyl-2-pentanol. These products were seen in addition to propylene and acetone. Catalytic characterization of Li_1–x H _x AlO₂;x = 0.90 with 2-propanol showed a significant decrease in condensation activity and no change in the propylene/acetone ratio relative to LiAlO₂. This suggests that the decrease in the amount of lithium eliminated the basic sites necessary for the condensation reactions.     

Surface Exchange of Oxygen in La1−x Sr x FeO3−δ (x = 0, 0.1)

The electronic charge carrier concentration in La_1?x Sr _x FeO_3?δ was shown to depend on the partial pressure of O₂ (pO ₂). Chemical diffusion coefficient and surface exchange coefficient, k _chem, were determined by conductivity relaxation in O₂/N₂ and CO/CO₂ mixtures. k _chem was proportional to pO ₂ ^1.06 in O₂/N₂, while in CO/CO₂ k _chem was controlled by a reaction mechanism involving both CO and CO₂.     

Thermal decomposition of K1 − x Cs x BSi2O6 borosilicates

Thermal decomposition of mixed K_{1 ? x} Cs _x BSi₂O₆ borosilicates by the methods of thermal analysis, annealing, and quenching, with the following refining of the structure by the Rietveld method on the example of solid solutions with x = 0.3 and 0.7 crystallizing in the space groups $I4\bar 3d$ and $Ia\bar 3d$ , respectively, is studied. It is shown that the solid-phase decomposition of borosilicates proceeds with the release of the gas- eous phase and formation of cristobalite and/or tridymite of SiO₂ at the final stage. In this case the solid solutions enriched by potassium decompose in one stage with the formation of SiO₂, while the solutions enriched by cesium decompose with the formation of the intermediate zeolite-like CsBSi₅O₁₂ borosilicate, which also decomposes during further thermal treatment. According to the data of the structure, the refining of K_{1 ? x} Cs _x BSi₂O₆ solid solutions obtained by thermal treatment at 1000°C for 20, 65, 80, and 100 h, it is detected that for the samples with x = 0.3 and 0.7 the parameter of the cubic cell of the leucite-like phase decreases and the vacancies in the position of alkaline cation appear. During the solid-phase decomposition of K_{1 ? x} Cs _x BSi₂O₆ solid solutions the structure degrades.     

NiMn x Fe2 − x O4 ferrites: Combustion synthesis and characterization

Ferrites NiMn _x Fe_{2 ? x} O₄ (x = 0.0, 0.2, 0.4, and 0.6) were synthesized by SHS and hot sintering and comparatively characterized by ESM, EDS, and XRD; and a tentative mechanism of SHS reaction was suggested.     

LaCo1−x Pd x O3 Perovskite-Type Oxides: Synthesis, Characterization and Simultaneous Removal of NO x and Diesel Soot

A series of naometric perovskite catalysts LaCo_1?x Pd _x O₃ (x = 0, 0.01, 0.03) were prepared via a solution combustion synthesis route using metal nitrates as oxidizers and urea as fuel. It is essential to add a certain amount of ammonia aqueous solution to Pd²⁺ ions solution in the catalyst preparation process. Homogeneous nanoparticles LaCo_1?x Pd _x O₃ catalysts with the sizes in the range of 68–122 nm were obtained and characterized by using of XRD, BET, H₂-TPR, XPS, SEM and TEM. Pd was successfully introduced into the LaCoO₃ perovskite lattices. Further information was obtained by using XPS upon the LaCo_0.97Pd_0.03O₃ (with NH₄OH) sample after H₂-TPR. The results revealed that surface Pd was reduced to the metallic state at the end of the first step in the H₂-TPR experiment, and some surface Co could be reduced to metallic Co simultaneously. The catalytic properties were investigated for simultaneous NO _x -soot removal reaction. The performance of LaCo_1?x Pd _x O₃ catalysts were greatly improved by the partial substitution of Pd. The maximum NO conversion into N₂ and the ignition temperature of soot are 32.8% and 265 °C, respectively.     

高温风机的轴承改造x

焦作水泥厂Φ 4 2m× 65m四级悬浮预热器窑上高温风机引进于罗马尼亚，风量 220 000m3／ h，风压 6 370Pa， F式装配形式，径向式风叶，叶轮回转部分重约 3 000kg。轴承 22238K，相当于国产 153538轴承，轴承与轴靠紧定套锁紧定中。 1993年系统投运以来，轴承常出故障，为此于 2000年 1月对其支承部分进行了改造，改造中因有试验，也得到了其它方面的收获。 1 轴承损坏的原因及分析     

Preparation and electrochemical characterization of Ti/Ru x Mn1−x O2 electrodes

DSA^® type electrodes of ruthenium–manganese mixed oxides (30 at % Ru < 100) supported on titanium were prepared by the spray-pyrolysis technique, using Ru(NO)(OH) _x (NO₃)_3–x and Mn(NO₃)₂ as precursors. Electrodes were characterized by SEM, XRD and cyclic voltammetry. Their behaviour as anode for the chlorine and oxygen evolution reactions was also evaluated by polarization curves. The stability of the mixed oxides was determined through accelerated tests of service life. It has been verified that the best performance on the apparent electrocatalytic activity of both reactions as well as on stability is achieved at a composition of about 70% Ru.     

废CeO x -MnO x 基SCR脱硝催化剂还原酸浸综合回收铈锰

废选择性催化还原（SCR）脱硝催化剂中含有大量的有价金属,直接废弃易造成资源浪费及环境污染。以废CeO _x -MnO _x 基SCR脱硝催化剂为原料,采用热力学分析结合湿法冶金实验方法,研究了浸出条件对Ce、Mn元素浸出率的影响。结果表明,废催化剂直接酸浸Ce、Mn元素浸出率低,还原-酸浸Ce、Mn元素热力学条件上可行,抗坏血酸对Ce、Mn高价氧化物有明显的还原作用。当抗坏血酸质量分数为30%、硫酸浓度2mol/L、液固比6∶1、搅拌速度350r/min、80℃恒温反应5h时,Ce、Mn的浸出率分别达到92.09%、95.51%。加入抗坏血酸后,部分Ce⁴⁺和Mn⁴⁺还原为Ce³⁺和Mn²⁺,Ce⁴⁺/Ce的比值由75.82%降低到71.62%,Mn⁴⁺/Mn的比值由29.39%降低到27.17%,同时削弱了高价Ce辅助低价Mn向高价Mn转化的作用,使得Ce、Mn高效浸出,为CeO _x -MnO _x 基废催化剂中Ce、Mn资源化利用奠定了基础。     

Preparation of La1?x Sr x CoO3 Oxide Electrode Material and its Influence on the Structure and Dielectric Performance of the Supported Ba1?x Sr x TiO3 Thin Films

Using the sol–gel method, La_1−x Sr _x CoO₃ (LSCO) electrode films were first fabricated on the Si (100) substrates, followed by the growth of Ba_1−x Sr _x TiO₃ (BST) thin films on the LSCO electrode film. The crystal structure and surface morphology of these films were characterized by XRD and SEM. The effects of Sr-doping and annealing temperature on the structure and electric resistivity of the LSCO films and the dielectric properties of the BST films were studied. Results show that the La_0.5Sr_0.5CoO₃ electrode annealed at 750 °C has the lowest electric resistivity, 1.1 × 10⁻³Ω cm. The relative permittivity of the La_0.5Sr_0.5CoO₃-supported BST films first increases and then decreases with Sr-doping. The relative permittivity of the BST film decreases while the dielectric loss increases with frequency. Among the studied BST films, Ba_0.5Sr_0.5TiO₃ has the largest relative permittivity and the smallest dielectric loss (95 and 0.1, respectively) when the frequency is 1 kHz.     

Structural and ion transport properties of [(AgI)x(AgBr)0.4−x](LiPO3)0.6 and (AgBr)x(LiPO3)(1−x) solid electrolytes

The (AgBr)_x(LiPO₃)_(1−x) (x=0.4 and 0.5) and [(AgI)_x(AgBr)_0.4−x](LiPO₃)_0.6 (x=0.1, 0.2, and 0.3) superionic electrolytes have been prepared by conventional melt quenching using a twin roller. These electrolytes are characterized by X-ray diffraction, SEM, and energy dispersive X-ray analysis (EDAX) for structural investigation. Electrical characterizations have been carried out by the AC impedance analysis. The conductivity of LiPO₃ glassy system at room temperature is improved by doping with the silver bromide (AgBr)_x(LiPO₃)_(1−x) and the mixture of silver iodide, silver bromide (AgI-AgBr-LiPO₃ system) up to 10⁻⁵ and 10⁻³ Ω⁻¹ cm⁻¹, respectively (improvements by four or five orders of magnitude). The frequency response of ionic conductivity has been analyzed by universal dynamic response model (Jonscher's law) and AC conductivity data are fitted using the Jonscher's power law. The conductivity values obtained by the power law and impedance plots are comparable. The frequency exponent (n) has a value between 0 and 1. The AgI-AgBr-LiPO₃ system shows the mixed alkali effect. Summerfield scaling master curve is temperature dependent, which may be due to the contribution of the both lithium and silver ions to ionic conduction.     

Synthesis,characterization and catalytic properties of La2−x Sr x NiO4−δ

Various compositionsx in the catalyst system La_2–x Sr _x NiO_4– have been prepared by conventional techniques and characterized by X-ray powder diffraction, electron microscopy and BET surface measurements. The catalytic properties of these catalysts have been tested in the propylene oxidation reaction. The catalytic activity can be correlated with the oxygen content and with the strontium substitution.     

锦x块地质特征再认识

针对锦x块开发井主要集中在区块的北部,断块构造复杂,区块西部空白区控制井少,构造不够落实,油层发育变化较大,为挖掘该块潜力,进一步落实该块的构造及储层发育情况,为下一步部署开发井提供有力依据,我们对该块进行了地质研究,主要开展了构造、储层、沉积相研究等工作。     

Thermal characterization of Se78 − x Te20Sn2Pb x (0 ≤ x ≤ 6) glassies for phase change optical recording technique

New multi-component glasses of Se_{78 ? x} Te₂₀Sn₂Pb _x (0 ≤ x ≤ 6) system have been synthesized using melt-quench technique. Differential Scanning Calorimetric measurements are performed at different heating rates under non-isothermal conditions to study the glass transition kinetics of prepared chalcogenide glass. Different kinetic parameters such as the activation energy of glass transition, thermal stability, glass forming ability etc have been determined. The composition dependence of kinetic parameters of glass transition is also discussed.     

胶条x光机异物自动检测剔除设备

轮胎工厂挤出压延车间将胶料加工成各种橡胶半成品,再输送至成型车间组合成型。若胶料中带有金属杂物,易损坏挤出机的螺旋喂料杆。同时带有金属杂物的橡胶半成品流入下一工序,会影响轮胎质量或造成轮胎报废,增加生产成本。因此对于轮胎企业来讲,金属检测设备的连续化和自动化是发展的趋势和要求。而胶条X光机异物自动剔除设备正好能够满足设备自动化的要求,因此能得到广泛的应用。     

QX小型x荧光光谱仪的应用

ＱＸ小型ｘ荧光光谱仪的应用李延冬，王江山东潍坊水泥厂（２６１０５５）我厂１９９３年２月使用从国外引进的ＱＸ小型多道波长色散ｘ荧光光谱仪用于分析控制，９个固定道可同时准确测定９种元素（Ｎａ、Ｍｇ、Ａｌ、Ｓｉ、Ｓ、Ｃｌ、Ｋ、Ｃａ，Ｆｅ），分析时间２ｍｉｎ...     

New solid solutions of mixed alkali-zinc diphosphates LiNa1 − x K x ZnP2O7

Phase relationships in the LiNaZnP₂O₇-LiKZnP₂O₇ system have been studied. For the first time a vast region of solid solutions of the rhombic syngony LiNa_{1 ? x} K _x ZnP₂O₇ containing simultaneously three alkali cations was found. The miscibility is broken at the temperature of the polymorphous transformations LiKZnP₂O₇ (270°C) and below, with the formation of the two-phase region of the solid solution with the rhombic and monoclinic structures (0.85 ≤ x ≤ 1 at 25°C).     

Microstructure and properties of (1 − x)La0.9Ca0.1CrO3/x ZrO2 (x = 0–30 wt-%) composites

The microstructure and properties of Ca doped lanthanum chromate [La_0.9Ca_0.1CrO₃ (LCCO)] and zirconia (ZrO₂) composites [abbreviated as (1???x)LCCO/xZrO₂, x?=?0–30?wt-%] prepared by solid state reaction method are investigated in this paper whose potential application in heat resistant ceramics are also discussed. The growth and fusion of the LCCO grains are hindered by the ZrO₂ grains, which make the matrix grains refined. In the stable system, it is discovered that the density of the composites decreases, the porosity increases and the decrease amplitude of the bend strength after thermal shock at 600°C reduces with the increasing ZrO₂ content, which results in diminishing the bend strength gradually and enhancing the thermal shock resistance. When x?=?10–15?wt-%, the samples show the best thermal shock resistance realising a maximum thermal cycle times of 8. The material with x?=?20?wt-% exhibits excellent slag resistance.     

Composition dependence of the oxygen-evolution reaction rate on Ir x Ti1−x O2 mixed-oxide electrodes

Mudcrack-free oxide films of Ir _x Ti_1–x O₂ (0 < x 1) on titanium substrates were obtained, and the effects of the oxide composition on the rate of oxygen-evolution reaction were investigated. At x 0.6, Ir-rich grains appear on the mudcrack-free surface. In the purely single-phase region (0 < x 0.5), the pseudo-capacitive charge is proportional to the surface composition, x _s, and the exchange-current density for the oxygen-evolution reaction increases linearly with x _s at 0.2 x _s 0.5, with an extrapolated intercept at x _s 0.15, below which the oxides are inactive.