神府和胜利煤液化残渣CS_2萃取物的组成分析

以CS2作为溶剂,对神府和胜利煤液化残渣进行了常温萃取,利用GC/MS对萃取物进行分析,考察产物中各族组分的分布规律,进而比较两种煤液化残渣的分子结构特征.结果表明:在神府和胜利煤液化残渣的萃取物中分别检测到33和22种化合物,主要由大分子的芳烃、脂肪烃和含杂原子有机化合物组成.芳烃包括4-7环的稠环芳烃及其烷基取代衍生物,其中6环的苯并[ghi]苝含量最高,脂肪烃主要为正构烷烃和取代烷烃,含杂原子有机化合物主要以含氧和含硫元素的化合物为主.     

Synthesis of glass ceramics from kaolin and dolomite mixture

Cordierite-and anorthite-based binary glass ceramics of the CaO-MgO-Al₂O₃-SiO₂ (CMAS) system were synthesized by mixing local and abundant raw minerals (kaolin and doloma by mass ratio of 82/18). A kinetics study reveals that the activation energy of crystallization (Ea) calculated by the methods of Kissinger and Marotta are 438 kJ·mol-1 and 459 kJ·mol-1, respectively. The Avrami parameter (n) is estimated to be approximately equal to 1, corresponding to the surface crystallization mechanism. X-ray diffraction (XRD) analysis shows that the anorthite and cordierite crystals are precipitated from the parent glass as major phases. Anorthite crystals first form at 850℃, whereas the μ-cordierite phase appears after heat treatment at 950℃. Thereafter, the cordierite allotropically transforms to α-cordierite at 1000℃. Complete densification is achieved at 950℃; however, the density slightly decreases at higher temperatures, reaching a stable value of 2.63 kg·m-3 between 1000℃ and 1100℃. The highest Vickers hardness of 6 GPa is also obtained at 950℃. However, a substantial decrease in hardness is recorded at 1000℃; at higher sintering temperatures, it slightly increases with increasing temperature as the α-cordierite crystallizes.     

Effect of Pd doping on the acetone-sensing properties of NdFeO<Subscript>3</Subscript>

The acetone-sensing properties of the undoped and Pd doped perovskite-type oxides NdFeO₃ were investigated from room temperature to 400°C. The perovskite-type NdFeO₃ was synthesized by a sol-gel method, and the dopants Pd with the content from 1wt% to 5wt% were implanted into NdFeO₃ nanoparticles by thermal diffusion. X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques show that NdFeO₃ is an orthorhombic structure with the average particle size of about 40 nm. A giant acetone-sensing response of 675.7 is observed when the Pd content in NdFeO₃ powders is about 3wt%. The response and recovery time of the sensor to the 5×10⁻⁴ acetone gas are 16 and 1 s, respectively. At the same time, it performs a good selectivity to acetone gas and may be a new promising material candidate for the acetone-sensor development.     

Thermal behavior of zirconia-dop ed mullite gel fibers

The zirconia-doped mullite gel fibers were prepared via a sol-gel method.The thermal behaviors of the gel fibers during pyrolysis were investigated by means of thermal gravitydifferential scanning calo...     

Effect of modifying agents on the hydrophobicity and yield of zinc borate synthesized by zinc oxide

The aim of this study was to synthesize zinc borate using zinc oxide, reference boric acid, and reference zinc borate (reference ZB) as the seed, and to investigate the effects of modifying agents and reaction parameters on the hydrophobicity and yield, respectively. The reaction parameters include reaction time (1–5 h), reactant ratio (H₃BO₃/ZnO by mass: 2–5), seed ratio (seed crystal/(H₃BO₃+ZnO) by mass: 0–2wt%), reaction temperature (50–120℃), cooling temperature (10–80℃), and stirring rate (400–700 r/min); the modifying agents involve propylene glycol (PG, 0–6wt%), kerosene (1wt%–6wt%), and oleic acid (OA, 1wt%–6wt%) with solvents (isopropyl alcohol (IPA), ethanol, and methanol). The results of reaction yield obtained from either magnetically or mechanically stirred systems were compared. Zinc borate produced was characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and contact angle tests to identify the hydrophobicity. In conclusion, zinc borate is synthesized successfully under the optimized reaction conditions, and the different modifying agents with various solvents affect the hydrophobicity of zinc borate.     

Properties improvement of SPEEK based proton exchange membranes by doping of ionic liquids and Y2O3

The membranes of sulfonated poly(etheretherketone) with 65％ sulfonation degree were prepared by doping of Y2O3 and ionic liquids,such as 1-ethyl-3-methylimidazole tetrafluoroborate (EB) or 1-butyl-3-me...     

Carbothermal synthesis of Si3N4 powders using a combustion synthesis precursor

Si₃N₄ powders were synthesized by a carbothermal reduction method using a SiO₂ + C combustion synthesis precursor derived from a mixed solution consisting of silicic acid (Si source), polyacrylamide (additive), nitric acid (oxidizer), urea (fuel), and glucose (C source). Scanning electron microscopy (SEM) micrographs showed that the obtained precursor exhibited a uniform mixture of SiO₂ + C composed of porous blocky particles up to ～20 μm. The precursor was subsequently calcined under nitrogen at 1200–1550°C for 2 h. X-ray diffraction (XRD) analysis revealed that the initial reduction reaction started at about 1300°C, and the complete transition of SiO₂ into Si₃N₄ was found at 1550°C. The Si₃N₄ powders, synthesized at 1550°C, exhibit a mixture phase of α- and β-Si₃N₄ and consist of mainly agglomerates of fine particles of 100–300 nm, needle-like crystals and whiskers with a diameter of about 100 nm and a length up to several micrometers, and a minor amount of irregular-shaped growths.     

Molten-salt synthesis of tungsten oxide nanotubes： Morphological and gas sensitivity

A very simple molten-salt method was used to synthesize WO3 nanotubes at moderate temperature （600 ）. The outer and inner diameters of the WO3 nanotubes were about 100 nm and 30 nm,with a length of dozens of micrometers. TEM and XRD analyses showed that the WO3 nanotubes were single crystal, and had monoclinic structure with the axes preferentially aligned along the [011] direction. The photoluminescence and the gas sensitivity of the nanotubes had been tested, showing that the products very well responded to acetone at 340℃.     

Dispersion of CoCl2 into γ-Al2O3 studied by positron

Co²⁺/γ-Al₂O₃ samples were prepared by incipient wetness impregnation of γ-Al₂O₃ with different concentration solution of CoCl₂ and dried at 40 °C. We measured the positron lifetime spectra of the samples of different Co²⁺ mass fractions (0%–8.24%) heated at different temperatures (100–500°C). All lifetime spectra were resolved into four components, in which the third and the fourth components were related to the surface state of the micropores and the secondary pores of the γ-Al₂O₃. The experimental results showed that the Co²⁺ was mainly located in the micropores and the secondary pores near to the exterior of the support. For low Co²⁺ mass fraction samples, when the heating temperature was above 400 °C, dispersal was almost finished. When the Co²⁺ mass fraction was above 5.59%, Co²⁺ and Cl⁻ were dispersed into the secondary pores in the form of multiple layers.     

Improving the tensile properties of extruded Mg–Ga alloy by ageing treatment

A hot-extruded Mg-5Ga alloy was subjected to ageing treatment at 150 ?°C, 190 ?°C and 230 ?°C. The microstructures and mechanical properties of the extruded and aged alloy were examined in this study. Microstructure examinations suggested that particle-shaped and rod-shaped Mg₅Ga₂ were precipitated in the alloy after peak ageing treatment. The extruded alloy showed the yield strength, ultimate tensile strength and elongation to fracture of 157.6 ?MPa, 248.6 ?MPa and 17.5%, respectively. After peak ageing, the yield strength and ultimate tensile strength can be enhanced by as much as 15.7% and 8.6% reaching 182.3 ?MPa and 270 ?MPa, respectively. The improvement of the tensile strengths is mainly attributed to the enhanced precipitation strengthening by newly formed fine Mg₅Ga₂ precipitates. The ductility of the alloy was slightly increased by peak ageing at low temperatures (150 ?°C and 190 ?°C), but remarkably decreased by peak ageing at high temperature (230 ?°C) due to the formation of coarsened Mg₅Ga₂ particles which easily initiated the cracks during tensile deformation.     

Preparation, structure, and properties of polyurethane foams modified by nanoscale titanium dioxide with three different dimensions

TiO2-based nanosheets (TiNSs), TiO2-based nanotubes (TiNTs) were prepared by hydrothermal processing, and polyurethane foams with TiO2 nanopowders (P25), TiNSs and TiNTs were synthesized by free-rising foaming method. The Fourier-transform infrared (FT-IR) spectra show that the addition of titanium dioxide does not affect the chemical structure of polyurethane foam. However, microscope observations show that PU/TiNSs composite foams have more uniform cells and the average aperture smaller than that of pure poly-urethane foams. According to the results of thermal analysis, the PU/TiNSs composite foams have better thermal stability, the temperature of decompostion occurring with a maximum weight loss rate is about 30 ℃ higher than that of pure PU foams. The decompostion temperatures are 167 ℃ and 148 ℃ for the PU/P25 composite foams and the PU/TiNTs composite foams respectively, which are lower than that of pure PU foams. Moreover, with the addition of the fillers, the sound absorption property also has changed; the addition of TiNSs improved the sound absorbing property efficiently. The better thermal stability and sound absorption of PU/TiNSs composite foams are mainly due to the uniform cells diffuse and smaller aperture.     

Enhanced low-temperature performance of slight Mn-substituted LiFePO<Subscript>4</Subscript>/C cathode for lithium ion batteries

Low temperature performance of LiFePO₄/C cathode was remarkably improved by slight Mn-substitution. Electrochemical measurements showed that about 95% of the discharge capacity of LiFe_0.98Mn_0.02PO₄/C cathode at 20°C was obtained at 0°C, compared to 85% of that of LiFePO₄/C cathode. The LiFe_0.98Mn_0.02PO₄/C sample also presented enhanced rate performance at −20°C with the discharge capacities of 124.4 mA h/g (0.1C), 99.8 mA h/g (1C), 80.7mAh/g (2C) and 70 mA h/g (5C), respectively, while pristine LiFePO₄/C only delivered capacities of 120.5 mA h/g (0.1C), 90.7 mA h/g (1C), 70.4 mA h/g (2C) and 52.2 mA h/g (5C). Cyclic voltammetry measurements demonstrated an obvious improvement of the lithium insertion-extraction process of the LiFePO₄/C cathode by slight Mn-substitution. The results of FSEM observation and electrical conductivity measurement indicated that slight Mn-substitution minimized the particle size of LiFe_0.98Mn_0.02PO₄/C and also obviously improved the electrical conductivity of the compound, thus obviously enhances the interface reaction process on the cathode.     

Effect of trace Zn, P and Mg additions on microstructure and mechanical properties of Nb-Si-Ti alloys

The effects of Zn,P and Mg additions on the microstructure and mechanical properties of Nb-22Ti-3Si alloys were studied. The phases of Nbss and Nb_3Si presented in Nb-22Ti-3Si(AC1),Nb-22Ti-3Si-0.2Zn(AC2) and Nb-22Ti-3Si-0.2Mg alloys(AC3). The Nb-22Ti-3Si-0.2P(AC4) alloy consisted of Nbss,Nb_3Si network and eutectic cell of Nbss/α-Nb_5Si_3.By the addition of Zn,the Nb_3Si network was broken and the volume fraction of Nbss increased from 92%to 96%.The values of fracture toughness of the alloy AC2 at ambien...     

Microstructure and mechanical properties of a hot-extruded Al-based composite reinforced with core-shell-structured Ti/Al3Ti

An Al-based composite reinforced with core-shell-structured Ti/Al₃Ti was fabricated through a powder metallurgy route followed by hot extrusion and was found to exhibit promising mechanical properties. The ultimate tensile strength and elongation of the composite sintered at 620℃ for 5h and extruded at a mass ratio of 12.75:1 reached 304 MPa and 14%, respectively, and its compressive deformation reached 60%. The promising mechanical properties are due to the core-shell-structured reinforcement, which is mainly composed of Al₃Ti and Ti and is bonded strongly with the Al matrix, and to the reduced crack sensitivity of Al₃Ti. The refined grains after hot extrusion also contribute to the mechanical properties of this composite. The mechanical properties might be further improved through regulating the relative thickness of Al-Ti intermetallics and Ti metal layers by adjusting the sintering time and the subsequent extrusion process.     

Mineralogical alteration of thermally treated siderite in air: Mössbauer spectroscopy results

Mineralogical alternation of thermally treated siderite in air atmosphere has been systematically analyzed by Mössbauer effects. It was preliminarily estimated from the area of subspectra that 4%, 39% and 62% of magnetite were formed at 410 °C, 490 °C and 510 °C respectively. After being incrementally heated at 530 °C the spectra consist of two sextets of Fe₃O₄. Sextet of γ-Fe₂O₃ with hyperfine field of 50T was observed at 550 °C. Spectra at 580 °C consisted of two sextets with hyperfine fields caused by γ-Fe₂O₃ and α-Fe₂O₃. Fe₃O₄ disappeared and the amount of γ-Fe₂O₃ decreased, while the quantity of α-Fe₂O₃ increased to 34% and 77% at 640 °C and 690 °C, respectively. During the early stage of decomposition and oxidation, FeO was probably produced but quickly oxidized to magnetite and unidentified in our experiment. These results, in good agreement with the X-ray diffraction analyses and microscopic observation, provide an interpretation to anomalous magnetic property changes of siderite-bearing rock samples.     

Extraction of vanadium from high calcium vanadium slag using direct roasting and soda leaching

The extraction of vanadium from high calcium vanadium slag was attempted by direct roasting and soda leaching. The oxidation process of the vanadium slag at different temperatures was investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The effects of roasting temperature, roasting time, Na₂CO₃ concentration, leaching temperature, leaching time, and liquid to solid ratio on the extraction of vanadium were studied. The results showed that olivine phases and spinel phases in the vanadium slag were completely decomposed at 500 and 800℃, respectively. Vanadium-rich phases were formed at above 850℃. The leaching rate of vanadium reached above 90% under the optimum conditions:roasting temperature of 850℃, roasting time of 60 min, Na₂CO₃ concentration of 160 g/L, leaching temperature of 95℃, leaching time of 150 min, and liquid to solid ratio of 10:1 mL/g. The main impurities were Si and P in the leach liquor.     

Spectroscopic investigation of the interaction between human serum albumins and 10-hydroxycamptothecin

The binding reaction between 10-hydroxycamptothecin (10-HCPT) and human serum albumins (HSA) is studied by means of fluorescence spectroscopy, UV-Vis absorption spectrum, 1H NMR spectrum, and molecular simulation. The results indicate that the binding reaction of 10-HCPT and HSA is a single static quenching process, and the binding equilibrium constant for 10-HCPT binding with HSA is estimated K ₀= 4.93×10⁴ L · mol⁻¹ at 25 °C with the molar ratio of 1:1. The distance (r) and energy transfer efficiency (E) between donor (HSA) and acceptor (10-HCPT) are obtained as follows, r =3.51 nm; E =0.27. The enthalpy change (ΔH ^⦵) and entropy change (ΔS ^⦵) are calculated at different temperatures, and the hydrophobic force and shidipole force are the functions in the reaction. The results show that 10-HCPT binds within the subdomain II A of HSA by the hydrophobic force, and the 10-OH and 20-OH of 10-HCPT bind with both residue Leu-238 of HSA and Ala 291 of HSA by hydrogen bonds. Biography: LI Guizhi(1962–), female, Associate professor, research direction: organic analysis.     

Microstructure and heat treatment for Ni3Al-based single crystal alloy with different crystal orientations

Ni₃Al-based single crystal alloy IC6SX with different crystal orientations were prepared by seed crystal method. The microstructure and heat treatment of the alloy were investigated. The results showed that the microstructure of the alloy was in dendrite structure, and the crystal orientation had significant effect on the dendrite morphology of this alloy. The precipitated phases of (MoNi)₆C and NiMo appeared in the microstructure of the three alloys with different crystal orientations during solidification process. Compared with other two alloys, the volume fractions of precipitated phases of both (MoNi)₆C and NiMo was the most in the alloy with [111] orientation and the least in the alloy with [001] orientation. The solidus and liquidus temperatures of the alloy IC6SX tested by differential scanning calorimetry (DSC) were 1356 °C and 1387 °C, respectively. Meanwhile, the effect of different solution temperatures on the microstructure of the alloy with different orientations was studied. The results showed that the precipitated phases of (MoNi)₆C and NiMo were eliminated with the solid solution treatment under the condition of 1300 °C/10 h. However, the incipient melting of the alloys occurred due to the dissolution of low melting point phases. As the temperature dropped to 1280 °C, the area of incipient melting in the alloy with different orientations decreased gradually. However, there was no incipient melting appearing in the three alloys with different orientations when the solution treatment temperature dropped to 1260 °C.     

Acetone hydrogenation in exothermic reactor of an isopropanol–acetone–hydrogen chemical heat pump: effect of intra-particle mass and heat transfer

Intra-particle mass and heat transfer plays an important role in performance of the exothermic fixed-bed reactor for an isopropanol-acetone-hydrogen chemical heat pump. In this work, an exothermic fixed-bed reactor model, taking into account the actual packing structure, is established in the commercial software Fluent. A 120° segment of a tube with tube-to-particle diameter ratio （n） of 4, where realistic particles are packed and set to porous media, is used to simulate the 3D external flow, concen- tration and temperature fields in the exothermic packed-bed reactor. The influence of catalyst particle diameter （dp） and micropore diameter （do） on the intra-particle temperature, species distribution, reaction rate and selectivity is dis- cussed. The appropriate dp and do are obtained. Simulation results showed that intra-particle temperature gradient is not obvious. Large dp and small do lead to remarkable gradient of reaction rate inside the catalyst particle and the decrease in the catalyst efficiency and reduce the acetone conversion and the selectivity in isopropanol. The optimal results reveal that the spherical catalyst with dp of 1 mm and dpore of 10 nm is appropriate for high-temperature acetone hydrogenation.     

Magnetic properties and thermal stability of sintered Nd-Fe-B magnet with Dy-Ni additive

A sintered(Nd_(0.8)Pr_(0.2))_(30.7)FebalB_(0.98)Cu_(0.2) magnet with 3% intergranular Dy_(85)Ni_(15) additive is prepared to study the magnetic properties and thermal stability of the Nd-Fe-B magnet. The results show that the magnet with or without additive obtains its optimum comprehensive magnetic properties at the sintering temperature of 1 030 ℃ and 1 040 ℃, respectively. The maximum coercivity of the magnet with additive reaches 15.16 k Oe, while that of the magnet without additive is just 11.88 k Oe. Further investigation on microstructure indicates that the grains of the magnet with additive form a modified "core shell" structure. Adding Dy_(85)Ni_(15) can significantly enhance the coercivity of Nd-Fe-B magnet and thus decrease its coercivity temperature coefficient.