Synthesis and stability evaluation of hierarchical silicoaluminophosphates with different structural frameworks in the methanol to olefins process

Silicoaluminophosphates (SAPOs) with different pore structures were synthesized through the implementation of polyethylene glycol (PEG) as a mesopores impregnation agent. Using PEGs with different molecular weights (MWs) and concentrations in the synthesis precursor, several samples were synthesized and characterized. Applying a PEG capping agent to the precursors led to the formation of tuned mesopores within the microporous matrix of the SAPO. The effects of the PEG molecular weight and PEG/Al molar ratio were investigated to maximize the efficiency of the catalyst in the methanol-to-olefin (MTO) process. Using PEG with a MW of 6000 resulted in the formation of both Zeolite Rho and chabazite structural frameworks (i.e., DNL-6 and SAPO-34). Pure SAPO-34 samples were successfully prepared using PEG with a MW of 4000. Our results showed that the PEG concentrations affect the porosity and acidity of the synthesized materials. Furthermore, the SAPO-34 sample synthesized with PEG (MW of 4000) and a PEG/Al molar ratio of 0.0125 showed a superior catalytic stability in the MTO reaction owing to the tuned bi-modal porosity and tailored acidity pattern. Finally, through reactivation experiments, it was found that the catalyst is stable even after several regeneration cycles.     

Composite anode material for lithium ion battery with low sensitivity to water

Here we demonstrate for the first time a novel kind of anode material with low sensitivity to water, which consists of natural graphite and deposited copper. Through measurement of X-ray photoelectron spectroscopy, thermogravimetric and differential thermal analysis and high resolution electron microscopy, it is found that copper exists at the surface of natural graphite in the forms of metallic copper and copper carbides. Since the deposited copper covers and removes some active sites at the surface of natural graphite, which absorbs water relatively easily, cycling behavior in the presence of high humidity (1000 ppm H₂O) is improved much. Concomitantly, reversible capacity enhances due to alloying of copper with lithium.     

Solubility and Dissolution Thermodynamics of Cefmetazole Acid in Four Neat Solvents and Preferential Solvation in Co-Solvent Mixtures of (Methanol,Ethanol or Isopropanol) + Water

The solubilities of cefmetazole acid in methanol, ethanol, isopropanol and water were determined experimentally by using the saturation shake-flask method within the temperature range from (278.15 to 303.15) K under pressure p?=?101.1 kPa. At a fixed temperature, the cefmetazole acid solubility falls in the order methanol?>?ethanol?>?isopropanol?>?water. The apparent dissolution enthalpy, dissolution entropy and Gibbs energy change were calculated. The acquired solubilities were correlated with Apelblat’s equation. The largest value of relative average deviation for mole fraction solubility was 0.45 × 10^?2, and of root-mean-square deviation, 0.747 × 10^?5. The type and extent and direction of solute–solvent interactions were identified using the concept of Linear Solvation Energy Relationship. In addition, the preferential solvation parameters (δx_1,3) of cefmetazole acid in co-solvent mixtures of methanol (1)?+?water (2), ethanol (1)?+?water (2) and isopropanol (1)?+?water (2) were derived via the inverse Kirkwood–Buff integrals method. At 298.15 K, the magnitude of preferential solvation of cefmetazole acid by the co-solvent is highest in methanol mixtures, followed by ethanol mixtures, and finally by isopropanol mixtures.     

双重光纤布拉格光栅的耦合理论分析

双重光纤布拉格光栅无论是在通信领域还是在传感领域都有着重要的应用价值。在分析双重光纤光栅折射率扰动特征的基础上,得出了它的耦合方程,并采用数值计算方法,对它的光谱特性及影响光谱特性的因素进行了系统的分析,重点讨论了两个光栅的关联特性,所用的分析方法和得到的结果对双重光纤光栅的制作和应用具有参考价值。     

A novel electrochemical conversion of CO2 with aryl hydrazines and paraformaldehyde into 1,3,4-oxadiazol-2(3H)-one derivatives in one step

Using CO₂ to replace phosgene or CO as the C1 synthon, we successfully achieved the one-pot electrochemical synthesis of 1,3,4-oxadiazol-2(3H)-one derivatives via a three-component coupling reaction of CO₂ with aryl hydrazines and paraformaldehyde in an undivided cell. With NaI as the electro-catalyst and t-BuOK as the base, this electrochemical process could be smoothly performed to afford the target products in good to high yields at room temperature.     

Pulsed ultrasound assisted dehydration of waste oil

A method to aid the separation of the oil phase from waste oil emulsion of refineries had been developed by using a pulsed ultrasonic irradiation technology. Compared with conventional continuous ultrasonic irradiation, it is found that pulsed ultrasonic irradiation is much better to make water drop coalescence and hence dehydration of waste oil. The effects of ultrasonic irradiation parameters on waste oil dehydration are further discussed. The orthogonal experiment is also designed to investigate the degrees of influence of ultrasonic parameters and the optimal technological conditions. Under the optimal experimental conditions, the water content of waste oil is decreased from 65% to 8%, which thereby satisfies the requirements of refineries on the water content of waste oil after treatment (<10%).     

Synthesis of new compounds in the series of aryl-substituted ureas with cytotoxic and antioxidant activity

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关于模的最大有理扩张

ｉ）设Ｍ_ｉ为一族左Ｒ－模,记Ｍ_ｉ为Ｍ_ｉ的最大有理扩张,本文首先考察了∑⊕Ｍ_ｉ和∑⊕Ｍ_ｉ之间的关系,并证明了如对环Ｒ上任何一族模上述两者相等的充要条件是环Ｒ上每一个模都有理完全．ｉ）利用ｉ）研究了无零因子环上模的最大有理扩张,得到了一些结果．