Study on the In-situ Synthesis of Aluminum Titanate Sintered by Waste Aluminum Slag

Aluminum titanate was in-situ synthesized by using industrial waste-residue in the aluminum factory and TiO2 as the main raw materials and the influence of different reaction temperatures on the purity and microstructures of synthesized products were mainly discussed. The obtained Al2TiO5 was characterized by X-ray diffraction （XRD）, scanning electron microscopy （SEM） and relevant analytical software. The results show that elevating the sintering temperature can increase the content of aluminum titanate; and at 1420 ℃, it reaches the highest in the synthesized ceramic. When the sintering temperature continues to increase, the produced aluminum titanate will decompose resulting in the drop of its content. Therefore, the optimum sintering temperature of in-situ synthesis of aluminum titanate is determined as 1420 ℃, at which the grains of aluminum titanate grow completely, the purity of aluminum titanate is 89.3wt%., the highest density is 2.75 g/cm^3, and the porosity is 9%.     

高频燃烧红外吸收光谱法测定高纯铝粉中碳含量

高纯铝粉在粉末冶金领域应用广泛,其碳含量的高低对材质的物理性能有较大影响,研究快速准确测定高纯铝粉中碳含量方法具有实际意义.采用高频感应燃烧红外碳硫仪测定高纯铝粉中碳含量,优化实验条件,建立高纯铝粉中碳含量测定的高频燃烧红外吸收光谱法.实验表明,称取0.1 g试样,在1980 W分析功率下,按照2.4:0.2:0.2质...     

AIN纳米微粉的微波合成

Nanometer aluminum nitride powder with purity higher than 98wt% and diameter in the range of 5-80nm has been obtained by microwave heating using α-Al2O3、Al(OH)3、 colloidal Al(OH)3 as the source for aluminum, and phenolformaldehyde resin, char, nanometer carbon black powder as the source for carbon, respectively. The effect of the type of starting materials and synthesis conditions on the purity and the size of the nanometer AlN powder has been analyzed in this paper.     

Corrosion behavior of aluminum exposed to a biodiesel

Aluminum was exposed to biodiesel with different levels of contaminants and impurities, and its corrosion behavior was evaluated by conventional electrochemical techniques. It was found that the corrosion behavior of aluminum in biodiesel contaminated with alkalis is similar to the corrosion behavior of aluminum in aqueous solutions. In addition, it was demonstrated that corrosion of aluminum can be used as a quantitative indication of the biodiesel purity.     

Corrosion-Electrochemical Behavior of Special-Purity Aluminum and Its AK1 Alloy Alloyed with Scandium

The anodic behavior of aluminum of varied purity, the effect of scandium on the corrosion resistance of AK1 alloy based on special-purity aluminum in NaCl electrolyte solutions was studied.     

利用铝废渣制备片状堇青石的影响因素研究

以铝厂废渣、高岭土、滑石为主要原料,采用固相法合成片状堇青石。分析了原料种类、原料配方、烧结温度、保温时间和晶核剂对合成堇青石的影响,并通过XRD、SEM进行表征。结果表明,原料的纯度越高合成的堇青石纯度越高;富含镁的配方能完全形成堇青石相;最佳烧成温度为1 380℃,保温时间为4 h,此时得到的堇青石纯度最高,且呈现片状结构,颗粒大小均匀;堇青石熟料可以起到晶核剂的作用,促进堇青石的生成。     

差示扫描量热法测定对乙酰氨基酚原料药纯度

建立差示扫描量热(DSC)法测定对乙酰氨基酚原料药纯度的方法。考察升温速率、称样量、坩埚类型对测定结果的影响,确定最佳测定条件:升温速率为1.0℃/min,称样量为2.0~2.2 mg,选用Tzero密封铝坩埚作为样品盘。DSC法测定对乙酰氨基酚原料药纯度为99.91%,测定结果的相对标准偏差为0.03%(n=6),DSC法测定结果与紫外可见分光光度法测定结果(99.85%)基本一致,且DSC法测定结果的相对标准偏差较小。该方法简便、快速、准确,无需标准品,可用于对乙酰氨基酚原料药纯度的测定。     

铝箔在盐酸中的交流电侵蚀的研究—Ⅱ.50周交流电正半周侵蚀

五种不同纯度电容器用铝箔(99.97—99.999%Al)在盐酸中用50周交流电正半周进行侵蚀。由于侵蚀膜是在断电半周低pH值下形成的,属透明钝化型薄膜,不堵塞侵蚀孔,因此不出现纯交流电侵蚀时的"掉粉"、"减薄"现象。实验结果表明,侵蚀形态以及表面积扩大率与箔的纯度,也即其自钝化能力有关。用电位波形图解释了得到的现象。     

Absorption and photoluminescence properties of 4-substituted Alq3 derivatives and tris-(4-hydroxypyridinoanthrene)aluminum

A series of 4-substituted Alq₃ derivatives have been synthesized. Photophysical properties of the complexes in solution have been studied in detail. The results show that Hammett σ_p constants of the substituents have a linear correlation with the emission maximum values of the aluminum complexes. Substitution at the 4-position improves the color purity of the emission and it has also a strong influence on the quantum yields. A new type of Alq₃ derivative, tris-(4-hydroxypyridinoanthrene)aluminum, has a good quantum yield and high emission color purity.     

Ultrasonic irradiation in the synthesis of trimethylaluminum from methyl iodide via methylaluminum sesquiiodide

Methyl iodide and aluminum powder were irradiated with ultrasound to form methylaluminum sesquiiodide, which was then treated with triethylaluminum to give trimethyaluminum in satisfactory yield (86%) and purity (95%).     

氮化钛的制备及表征

以金红石为原料 ,金属铝作还原剂合成氮化钛 ,以X射线衍射、热分析等方法进行测定 ,结果表明该法合成得到的氮化钛纯度较高 ,经济可行。     

Large-scale preparation of aluminum borate-coated aluminum oxide nanowires

Single-crystal and uniform aluminum borate (Al₄B₂O₉)-coated aluminum oxide nanowires have been synthesized in high purity and in large yield via a reaction of metal aluminum with boron oxide in the presence of carbon nanotubes (CNTs). The aluminum oxide nanowires exhibit a well-crystallized one-dimensional structure with diameters ranging from 50 to 70 nm, and the Al₄B₂O₉ have a coating thickness of about 1-5 nm. CNTs play a crucial role in the formation of the important ceramic nanowires, by providing a platform to grow the composite structure. The growth mechanism was proposed by the detailed microscopy observations.     

Effects of Calcining Temperature and Holding Time on the Synthesis of Aluminum Titanate

We aim in this research at synthesizing high-purity aluminium titanate with sludge from the aluminium profile factory by shock cooling method, and mainly discuss the effect of calcining reaction temperature and holding time on crystalline, microstructure and content of aluminum titanate materials to determine the preferred calcining temperature and holding time. XRD and SEM methods were utilized to characterize the crystalline and microstructure of each specimen, Rietveld Quantification software was used for the determination of different crystalline contents of specimens, and Philips plus software was applied to determine the cell parameters of aluminium titanate in different specimens. According to the experimental results, preferred calcining temperature is determined as 1400℃ and preferred holding time is 2 h, at which the grains of aluminum titanate grow completely and the purity of aluminum titanate is 97.2wt%.     

A continuous acetic acid system for polyacrylamide gel electrophoresis of gliadins and other prolamines

A polyacrylamide gel electrophoresis system buffered by acetic acid alone was developed for electrophoresis of prolamines. When applied to gliadin electrophoresis, the acetic acid system produces more bands than does a conventional aluminum lactate-lactic acid system (using 12% acrylamide gels). The acetic acid system is relatively simple, requiring a single buffer component that is universally available in high purity.     

Synthesis of Mordenite with the Use of Aluminum Sulfate Solutions

A procedure has been developed for synthesis of a mordenite-type zeolite with high phase purity and high dispersity of crystals. The procedure is based on hydrothermal crystallization of aluminum-silicon hydrogels prepared from aluminum sulfate solutions serving as a source of Al(III).     

悬浮液直接进样ICP–OES法测定高纯氧化铝中的铁、钛、硅、铬

采用悬浮液直接进样电感耦合等离子体发射光谱法(ICP–OES)测定高纯氢氧化铝中铁、钛、硅、铬的含量。悬浮液用电磁搅拌器搅拌,均匀地分散在溶液中,通过仪器蠕动泵进入雾化室,均匀无阻地导入ICP光源。Fe,Ti,Si,Cr的分析谱线分别为259.940,336.112,251.611,205.552 nm;RF功率为1 300W,等离子体气流量为13.0 L/min,雾化器气体流量为0.60 L/min,辅助气流量为1.00 L/min。Fe,Ti,Si,Cr的质量浓度分别在0.0~30.0,0.0~15.0,0.0~90.0,0.0~15.0μg/m L范围内与信号强度呈良好的线性,线性相关系数均大于0.999,方法的检出限为0.027 6~0.993 9μg/m L,测量结果的相对标准偏差为0.65%~6.84%(n=11),回收率为95.0%~104.8%。该法抗干扰能力强、线性范围宽,适用于高纯氢氧化铝中铁、钛、硅、铬含量的分析。     

以CTMABr和CTMAOH为共模板剂合成MCM-41

采用共模板剂水热合成了MCM-41.分别用X射线粉末衍射(XRD)、固体核磁共振(²⁷AlMASNMR)和N₂吸附等温线技术考察了用该方法和传统方法所制备的Si-MCM-41和Al-MCM-41样品的晶相结构、孔结构以及Al在分子筛中的化学环境.结果表明,用共模板剂方法合成的MCM-41样品,其纯度和孔径均一性显著提高,特别是当样品中Al含量较高时,仍可保证Al原子以四配位结合在MCM-41的硅骨架上.还就采用共模板剂的理论依据进行了讨论.     

Production of carrier free <Superscript>188</Superscript>Re radioisotope generator based on aluminum tungstate matrix

Improved radionuclide generator include a substantially insoluble salt of a radioactive parent which may be directly packed in column for subsequent elution of the daughter radionuclide. An improved ¹⁸⁸Re generator was prepared by reacting a radioactive tungsten (¹⁸⁸W) as parent radionuclide incorporated with aluminum chloride to obtain an insoluble radioactive aluminum tungstate matrix. The investigated matrix was characterized on the basis of the chemical composition, IR, thermal analysis and mechanical stabilities. The factors affecting the elution performance were studied such as influence of pH, molar ratio and drying temperature. From the obtained data, the molar ratio W:Al was 1.5:1 at pH = 4, the matrix dried at 105 °C for 2 h. Chromatographic and multichannel analysis has been currently used to investigate the radiochemical and radionuclidic purity respectively on eluted ¹⁸⁸Re. An elution yield more than 80%, with radiochemical purity <98% and radionuclidic purity <99% with a ¹⁸⁸W break through >10⁻⁴% of the column. The Al⁺³ and W contents value were about 2 and 3 μg/mL eluate. The obtained data approved the stability of the prepared generator and its suitability for medical application.     

Diastereoselective alkynylation of chiral phosphinoylimines: preparation of optically active propargylamines

Chiral phosphinoylimines were prepared from methylphenylphosphonamides and tested as new chiral and activated imines. The addition of aluminum acetylides was proved to be highly diastereoselective while lithium or magnesium acetylides gave poor results. The cleavage of the chiral auxiliary was done under mild conditions and allows the recovery of the starting phosphonamide without loss of optical purity.     

ASYMMETRIC REDUCTION OF CHIRAL SULFOXIDES BY OPTICALLY ACTIVE LITHIUM ALUMINUM HYDRIDE COMPLEXES WITH ALCOHOLS

Abstract

Optically active sulfoxides of low optical purity have been obtained by partial reduction of racemic sulfoxides using optically active lithium aluminum hydride-alcohol complexes as reducing agents. The steric course of the asymmetric reductions was found to be dependent on the composition of the complexes and on the configurations of optically active alcohols used. No configurational relationship between chirality at the sulfur and carbon atoms was observed.