Kinetics of the direct reaction between ozone and phenol by high-gravity intensified heterogeneous catalytic ozonation

In this study,high-gravity intensified heterogeneous catalytic ozonation is utilized for treatment of phenol-containing wastewater,and the kinetics of the direct reaction between ozone and phenol in the presence of excess tertiary butanol(TBA)is investigated.It is revealed that the direct reaction between ozone and phenol in the rotating packed bed(RPB)follows the pseudo-first-order kinetics with a reaction rate constant higher than that in the conventional bubbling reactor(BR).Under different conditions of temperature,initial pH,high-gravity factor,and gaseous ozone concentration,the apparent reaction rate constant varies in the range of 0.0160–0.115 min-1.An empirical power-exponential model is established to characterize the effects of these parameters on the direct reaction between ozone and phenol by high-gravity intensified heterogeneous catalytic ozonation.

Preparation and microstructure of in-situ(ZrB_2+Al_2O_3+Al_3Zr)_p/A356 composite synthesized by melt direct reaction

（ZrB2＋Al2O3＋Al3Zr）/A356 composites were synthesized by melt direct reaction from A356-（K2ZrF6＋KBF4＋Na2B4O7） system.The phase compositions and the microstructures of the as-prepared composites were investigated by XRD,SEM and TEM.The results show that the reinforcements are composed of ZrB2 and Al2O3 ceramic phase particles and Al3Zr intermetallic particles.The ZrB2 particulates are easy to join together to form some particle clusters and distribute along the α（Al） grain boundary.The morphologies of the ZrB2 particulates are in hexagon-shape with the size of about 50 nm.The TEM investigation results of Al3Zr indicate that Al3Zr grows in the form of facet with the length-diameter ratio of about 20.The morphologies of Al2O3 particles are in rectangular-shape and ellipsoidal-shape,with the size of about 0.1 μm.In addition,the interfaces of the matrix and particles are net and no interfacial outgrowth is observed.

Preparation of Al-Al_3Ti in situ composites by direct reaction method

Al-Al3Ti composites were prepared by a direct reaction method, in which Al3Ti was formed by the reaction of Ti and Al in aluminum alloy melt. The morphology of Al3Ti changes apparently from the fine particle, needle-like to large block with the increase of Al3Ti content. The addition of magnesium can markedly change the morphology of Al3Ti and reduce their size. Short rod-like Al3Ti was formed and homogeneous distribution was obtained with the addition of 3 wt.% Mg. The effect of Al3Ti and Mg on the microstructure of Al-Al3Ti composites and the mechanism were also discussed.

In-situ Preparation of Al/TiAl_3(P) Composite by Direct Reaction between Molten Al and TiO_2 Powder

TiAl3 particle reinforced pure Al composite has been made by direct reaction among molten Al, TiO2 and a flux. The composite exhibits high Synthetically properties. The strength and hardness are higher than those of pure Al matrix by 71.5% and 134% respectively However, the elongation is 20.36%, slightly lower than that of the Al matrix.

Reaction视频中用户弹幕信息交互行为的情感反应生成机理研究

深入挖掘Reaction视频中弹幕信息交互行为的情感反应机理有助于理解用户弹幕创作背后的情感生成原因及情感变化过程。本文基于情感反应模型,利用定向内容分析法对哔哩哔哩网站中11个热门视频的弹幕信息资源、视频内容以及reactor反应情况展开编码研究,构建了Reaction视频中用户弹幕信息交互行为的情感反应生成机理模型。研究发现,Reaction视频弹幕信息交互行为中的情感反应生成机理总体上遵循“信息刺激-情感反应”的路径,信息刺激有时会独立唤醒情绪或特定情感态度,有时也会通过唤醒特定情感态度进而影响情绪或内化情感态度的生成。该模型有助于提升情感反应理论在计算机协助交流中的情境化探索,也将为社交媒体中用户与信息交互提供优化建议。

PHASES AND STRUCTURE OF PREFORM DURING PREPARING PROCESS OF Al／TiCp COMPOSITES BY DIRECT REACTION SYNTHESIS

Direct reaction synthesis(DRS), based on the principle of self-propagating hightemperature synthesis (SHS), is a new method for preparing particulate metal matrix composites (PMMCs). The effects of the temperature of the aluminum melt and the aluminum content in the preform on the phases and structure of the reacted preform have been investigated by X-ray diffraction and scanning electron microscopy.It has been shown that TiC phase is prone to be synthesized with the increasing of the temperature of the aluminum melt and the decreasing of the aluminum powder content in the preform, and that the size of TiC particle becomes fine with the increasing of the temperature and the decreasing of the aluminum powder content.

Direct Dynamics Study on CH_2O + CH_3~·→ CHO + CH_4 Reaction

It is still a formidable challenge to study CH2O ＋ CH3·→ CHO ＋ CH4 reaction in the gas phase by traditional dynamics, because of the large number of freedom degrees for the system. In this paper, direct dynamics, in which trajectories were run directly on the DFT potential energy surface, have been applied to the reaction, which gave a direct look in the reaction processes. Two sets of trajectories at different initial orientations of reactants and temperature have been simulated. And the detailed reaction mechanisms have been described.

In-situ synthesized (Al_3Zr+Al_2O_3)_p /A356 composites by direct melt reaction in Al-Zr-O system

A novel in situ reaction system Al Zr O was developed. In situ Al 3Zr and Al 2O 3 particulate reinforced A356 alloy matrix composites have been fabricated by direct melt reaction method. The results show that the maximum sizes of Al 3Zr and Al 2O 3 particulates synthesized in the system ZrOCl 2 A356 are 1 μm and 3 μm respectively, and they are well distributed in the matrix. The investigation shows that the Al 3Zr crystal is in the shape of polyhedron and rectangle. There is a faceted growth phenomenon on Al 3Zr crystal surface. It is firstly found that the Al 3Zr crystal grows in the mechanism of twinning. The twinning plane is (1 1 4), and the twinning direction is [2 2 1] . The crystal morphology of in situ α Al 2O 3 particulate is rectangle or sphere. Furthermore, (Al 3Zr+Al 2O 3) p/A356 composites have not only higher tensile strength at room temperature (376.2 MPa) but also higher yield strength (319.4 MPa) and higher tensile strength at elevated temperature (200 ℃) than those of the A356 alloy. The dry sliding wear test shows that the wear resistance of the (Al 3Zr+Al 2O 3) p/A356 composites is greatly enhanced with increasing particulate volume fraction.

Direct Electrochemical Reaction of Horseradish Peroxidase Immobilized on the Surface of Active Carbon Powders

It is reported for the first time that horseradish peroxidase (HRP) immobilized on the active carbon can undergo a direct quasi-reversible electrochemical reaction. In addition, the immobilized HRP showed the stable bioelectrocatalytic activity for the reduction of H2O2.

DFT Study on the (S)-Proline-catalyzed Direct Aldol Reaction between Acetone and 4-Nitrobenzaldehyde

DFT/6-31G^＊ calculations were applied to study the direct aldol reaction between acetone and 4-nitrobenzaldehyde catalyzed by （S）-proline. Four transition states associated with the stereo-controlling step, corresponding to syn and anti arrangements of methylene moiety related to the carboxylic acid group in enamine intermediate and re and si attacks to the aldehyde carbonyl carbon have been obtained. The solvent effect of DMSO was investigated with polarized continuum model. The computed energies of transition states reveal the stereo-selectivity of the reaction.

Direct asymmetric aldol reaction using MBHA resin-supported peptide containing L-proline unit

MBHA resin-supported tripeptide catalyst system containing L-proline unit has been developed for use in the direct asymmetric aldol reaction of acetone and aldehydes, which afford the corresponding products with satisfactory isolated yields and enantiomeric excesses. 2009 Hong Bin Zou. Published by E]sevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

Study on reaction characteristics of phenolic hydroxyl in coal by using the model compound during direct coal liquefaction

The reaction characteristics of phenolic hydroxyl group were studied under the conditions of direct coal liquefaction. 2-naphthol was used as a coal model compound in this study. Under the conditions of with and without catalysts, a series of experiments were conducted at different temperatures, pressures and reaction time. Gas chromatography-mass spectrometry and gas chromatography were used to identify and quantify the reactants and products respectively. The conversion of 2-naphthol rises with the increase of reaction temperature, initial pressure and catalyst amount. The results indicated that tem- perature had a significant effect on 2-naphthol conversion, which promoted the dehydroxylation reaction. However, initial pressure had an important influence on the hydrogenation of 2-naphthol and naphthalene. The iron catalyst plays a significant role of cracking instead of hydrogenation. It is concluded that the harsh reaction conditions of high temperature, high pressure, and more catalyst are conducive to promoting dehydroxylation of 2-naphthol. The reaction mechanism was put forward based the experimental results, in which 2-tetralone was an intermediate.

Comparison of direct fecal smear microscopy,culture,and polymerase chain reaction for the detection of Blastocystis sp.in human stool samples

Objective:To compare the sensitivity and specificity of direct fecal smear microscopy,culture,and polymerase chain reaction in the detection of Blastocystis sp.in human stool.Methods:Human stool samples were collected from a community in San Isidro,Rodriguez,Rizal,Philippines.These samples were subjected to direct fecal smear microscopy,culture and polymerase chain reaction to detect the presence of Blastocystis sp.Results:Of the 110 stool samples collected,28(25%)were detected positive for the presence of Blastocystis sp.by two or more tests.Culture method detected the highest number of Blastocystis-positive stool samples(n=36),followed by PCR of DNA extracted from culture(n=26),PCR of DNA extracted from stool(n=10),and direct fecal smear(n=9).Compared to culture,the sensitivity of the other detection methods were 66.7%for PCR from culture and 19.4%for both PCR from stool and direct fecal smear.Specificity of the methods was high,with PCR from culture and direct fecal smear having97.3%,while PCR from stool at 95.9%.Conclusions:In this study,in vitro culture is the best method for detecting Blastocystis sp.in human stool samples.

Effect of tritium reduction in determining energy gain by using R-matrix method direct laser fusion in D-T reaction

The laser fusion criterion is known as the ρR-Criterion, also called high-gain condition. This parameter is temperature dependent and can be calculated by R-matrix method. This method is applied for determining improved fusion cross-section for the reactions T(d,n)4He, 3He(d,p)4He, D(d,p)T, D(d,n)3He. In this paper the time dependent reaction rate equations for fusion reaction T(d,n)4He are solved and by using the obtained results we computed the fu- sion power density, energy gain versus temperature and ρR-parameter. The obtained results show that a suitable com- bination may be a deuterium fraction fD=0.65 and fT=0.35 which would lead 30% reduction in the tritium content of the fuel mixture, and this choice would not change the energy gain value very much. Finally, the obtained energy gain for D-T reaction by using R-matrix is in good agreement with other theories.

ALTERNATING DIRECTIONFINITE ELEMENT METHOD FORSOME REACTION DIFFUSION MODELS

This paper is concerned with some nonlinear reaction - diffusion models. To solve this kind of models, the modified Laplace finite element scheme and the alternating direction finite element scheme are established for the system of patrical differential equations. Besides, the finite difference method is utilized for the ordinary differential equation in the models. Moreover, by the theory and technique of prior estimates for the differential equations, the convergence analyses and the optimal L2- norm error estimates are demonstrated.

应用DPRA替代方法评价3种香豆素类化合物的皮肤致敏性

应用直接多肽反应试验(DPRA)方法,对化妆品植物提取物原料中存在的蛇床子素、滨蒿内酯、东莨菪内酯3种未知致敏性的香豆素类化合物进行评价。3种香豆素类化合物与半胱氨酸多肽和赖氨酸多肽模拟的皮肤蛋白共同孵育,使用高效液相色谱法检测3种化合物的多肽消耗率。在标准色谱条件下,蛇床子素和滨蒿内酯与两种多肽的反应体系峰型均正常,东莨菪内酯与赖氨酸反应体系峰型异常,以体积分数0.1%的甲酸水-乙腈流动相体系对标准流动相体系进行优化后检测。结果表明:蛇床子素与半胱氨酸反应体系在反应24 h前产生沉淀,致敏性结果为不确定;滨蒿内酯多肽消耗率均值为6.95%,判定致敏性为阳性,反应等级为弱反应;东莨菪内酯的半胱氨酸多肽消耗率为75.82%,优化色谱条件后的赖氨酸多肽消耗率为80.46%,判定致敏性为阳性,反应等级为中度反应。阳性和阴性对照化合物的结果均与小鼠淋巴结试验(LLNA)致敏性结果一致,实验结果可为3种香豆素类化合物的致敏性提供参考和依据。

铅银渣混配铅精矿直接还原熔炼成渣特性及动力学解析

利用铅火法熔炼资源化消纳铅银渣等含铅固废已成为大势所趋。然而,由于原料结构明显差异导致常规高铅渣直接还原控制理论并不适用于混配铅银渣的反应过程。为此,在原料赋存状态及热力学分析基础上,结合还原实验对资源化消纳铅银渣的直接还原过程成渣特性及反应动力学规律进行了研究。结果表明,还原初期及还原后期(>30 min)均受界面反应控制,还原20~30 min内受外扩散控制,可通过增大反应界面及降低黏度来强化还原反应效率。随还原过程进行,渣中含铅相不断减少,锌黄长石相和铁锌尖晶石不断增加,硅酸盐结构由简单SiO_(4)^(4-)变为Si_(2)O_(7)^(4-),还原渣熔化温度及黏度均有所增加;控制终渣FeO/SiO_(2)=1.6,CaO/SiO_(2)=0.6,ZnO≤20 wt.%,可满足还原熔炼生产要求。

直接法合成棕榈酰基甲基牛磺酸钠的催化剂筛选和反应动力学

N-酰基氨基酸型表面活性剂具有优良的表面活性、安全性和生物降解性,广泛应用于日化、医药和食品等领域。以棕榈酸和N-甲基牛磺酸钠为原料经直接法合成棕榈酰基甲基牛磺酸钠,对比分析了金属氧化物、金属氯化物和硼酸系催化剂对棕榈酰基甲基牛磺酸钠合成反应的影响,筛选出适宜的催化剂,并进行反应动力学研究。结果表明,2-氯苯硼酸可有效催化棕榈酰基甲基牛磺酸钠的合成反应,当2-氯苯硼酸质量为棕榈酸质量的4%时,棕榈酰基甲基牛磺酸钠的收率达到97.5%,选择性达到98.4%。在棕榈酸过量的情况下,反应活化能为68.0 kJ/mol,指前因子为1.6×10^(10 )h^(−1)。

酶促4+2和2+2环加成反应:区域与立体选择性的理解与应用

4+2和2+2环加成反应均是构筑环结构的重要有机化学反应,在复杂天然产物、手性药物的化学合成和生物合成方面有广泛的应用。发现、发展包括4+2和2+2在内的酶促环加成反应,是当前化学生物学研究的热点之一。近期,国际、国内研究团队相继报道了多个酶促4+2和2+2环加成反应,解析了环化酶的蛋白结构和催化机制,设计了新的环化酶,或通过定向进化实现了不同类型环加成反应的区域和立体选择性调控。相关研究为采用合成生物学的策略设计和优化新型环加成酶提供了理论基础和成功范例,有利于促进酶促反应在有机合成领域的应用。