Luminescence properties of Eu3+ or Dy3+/Au co-doped SiO2 nanoparticles

Silica nanoparticles, prepared by the Stober method, have been doped with Eu³⁺, Dy³⁺, or processed to result in Au nanoparticles on the silica surface. The luminescence of the rare earth (RE)-doped SiO₂ particles has been studied as a function of the nature of the RE, their concentration and also of the presence of Au nanoparticles at the surface of the SiO₂ nanoparticles. We have shown that the Eu³⁺ emission is observable over the experimental conditions examined, whereas it was not possible to observe any emission for Dy³⁺ doped materials. No enhancement of the Eu³⁺ emission was observed following the adsorption of gold nanoparticles at the surface of the SiO₂ nanoparticle, however an excitation at 250 nm leads to both the emission of the matrix and Eu³⁺ showing an energy transfer from the SiO₂ matrix to Eu³⁺ ions.     

低起球涤纶短纤织物的染整工艺

研究了低起球涤纶织物与普通涤纶织物染整加工的不同,讨论了影响低起球涤纶短纤织物起球的几个因素.研究表明,与普通涤纶相比,低起球涤纶对碱用量更敏感,碱减量更容易,强力损失更严重,在染色过程中更容易上染.在低起球涤纶抗起球工艺中,碱减量与轧染工艺使织物抗起球效果更明显,浸染染色时间长短基本不影响其抗起球等级;柔软整理会降低其抗起球效果.     

A new heptamolybdate-based supramolecular compound with an alternating organic and inorganic layer structure: Synthesis,crystal structure and properties of (Hapy)4[Co(H2O)5Mo7O24] · 9H2O

A new supramolecular compound based on the heptamolybdate anion, formulated as (Hapy)₄[Co(H₂O)₅Mo₇O₂₄] · 9H₂O (1) (apy = 2-aminopyridine), has been synthesized hydrothermally and characterized by elemental analyses, IR, and X-ray single crystal diffraction. Compound 1 crystallizes as alternating layers of inorganic anions and organic cations linked by hydrogen-bonding interactions. A variable-temperature magnetic susceptibility measurement of 1 demonstrated the presence of antiferromagnetic interactions. Furthermore, the cyclic voltammogram of 1 shows two reversible redox couples both of which are associated with two-electron processes of molybdenum.     

Effect of inorganic salts on ferric oxalate-induced decomposition of CI Acid Black 234 under different weather conditions

In this study, sodium chloride and sodium sulphate were used for investigating their effects on photocatalytic decomposition of a triazo acid dye, CI Acid Black 234, used widely for the coloration of leather and wool products by the Fe ⁱⁱⁱ -oxalate complexes/hydrogen peroxide system under different weather conditions, respectively. Moreover, the photocatalytic degradation and mineralisation of CI Acid Black 234 was also examined by ultraviolet–visible spectrum and total organic carbon measurements. The results indicated that photocatalytic decoloration of CI Acid Black 234 was significantly limited in the presence of inorganic salt. Increasing the concentration of inorganic salt led to a lower decoloration percentage and kinetic reaction constant. The effect of inorganic salt on dye decomposition varied with solar light intensity. Sodium chloride exhibits a much stronger reduction effect on photocatalytic decoloration, degradation and mineralisation than sodium sulphate at similar reaction conditions, especially on a cloudy day.     

Biofilm deposited by the atmospheric plasma liquid sputtering

The biofilm of allylamine polymer was deposited by using the liquid sputtering apparatus, which was achieved by the atmospheric cold plasma plume. The surface roughness of the polymer was improved by increasing the power and He gas velocity. The average allylamine polymer deposition rate was about 30 nm/min. Rich morphologies (e.g., nanoline, microcloudlet) appearing on the biofilm revealed the important information of the growing processes that occurred in the plasma deposition. The density of the amine groups was obviously related to the plasma parameters, and the highest density of amino-labeled DNA probe was about 0.9 pM/cm² confirmed by the dyed oligonucleotide.     

聚丙烯切片样品粒度与用量对其熔融曲线的影响

在差示扫描量热分析过程中,通过改变样品粒度及用量,考查了对聚丙烯切片热行为的影响。结果表明:样品粒度变大或样品用量增加会导致熔融峰顶温度升高,同时会使熔融焓有轻微变化。因此在仪器的灵敏度可满足的情况下,为得到切片真实结晶结构参数的有效方法是减少样品用量(例如5 mg以下)。     

A site-isolated mononuclear iridium complex catalyst supported on MgO: Characterization by spectroscopy and aberration-corrected scanning transmission electron microscopy

Supported mononuclear iridium complexes with ethene ligands were prepared by the reaction of Ir(C₂H₄)₂(acac) (acac is CH₃COCHCOCH₃) with highly dehydroxylated MgO. Characterization of the supported species by extended X-ray absorption fine structure (EXAFS) and infrared (IR) spectroscopies showed that the resultant supported organometallic species were Ir(C₂H₄)₂, formed by the dissociation of the acac ligand from Ir(C₂H₄)₂(acac) and bonding of the Ir(C₂H₄)₂ species to the MgO surface. Direct evidence of the site-isolation of these mononuclear complexes was obtained by aberration-corrected scanning transmission electron microscopy (STEM); the images demonstrate the presence of the iridium complexes in the absence of any clusters. When the iridium complexes were probed with CO, the resulting IR spectra demonstrated the formation of Ir(CO)₂ complexes on the MgO surface. The breadth of the ν_CO bands demonstrates a substantial variation in the metal–support bonding, consistent with the heterogeneity of the MgO surface; the STEM images are not sufficient to characterize this heterogeneity. The supported iridium complexes catalyzed ethene hydrogenation at room temperature and atmospheric pressure in a flow reactor, and EXAFS spectra indicated that the mononuclear iridium species remained intact. STEM images of the used catalyst confirmed that almost all of the iridium complexes remained intact, but this method was sensitive enough to detect a small degree of aggregation of the iridium on the support.     

Adsorption and dehydrogenation of methanol on alkali-cation-exchanged zeolite: A first-principles density functional study

The adsorption and dehydrogenation of methanol on an alkali-cation-exchanged zeolite model, M-zeolite (M = Na⁺, K⁺, Rb⁺, and Cs⁺), were studied using first-principles calculations based on density functional theory (DFT). The adsorption energies, geometric structures, and vibrational frequencies of the transition states were computed by full-geometry optimization with a 6MR (membered-ring) cluster model. We have calculated the transition states and adsorption complexes of the reactants, transition states, and products, as well as the corresponding activation barriers and adsorption energies of the numerous reactions involved in these processes. The interaction first leads to the formation of a methanol complex, where the methanol via the oxygen atom and the alkali metal cation of the 6MR. Then, a transition state involves the coordination of two hydrogen bonds. Finally, the adsorbed formaldehyde and hydrogen complex is formed. The calculated results are compared with the data obtained from previous experimental studies.     

PET酯化蒸气能量回收技术和应用

介绍了2种酯化水蒸气余热回收利用的方法,直接制冷法和热水法,并从流程、布置要求和投资上对2种方案进行了对比,并对其经济性进行了分析。使用溴化锂制冷机组和热水换热器回收酯化废热蒸汽能量,夏天制取冷冻水,冬天生产空调热水,节约能耗的同时,实现废热的综合利用。