Synthesis, characterization and catalytic performance of a novel zeolite ITQ-2-like by treating MCM-22 precursor with H2O2

A novel zeolite material denoted as ITQ-2-like was synthesized by treating MCM-22 precursor with H₂O₂ and characterized by various physicochemical techniques (X-ray powder diffraction, transmission electron microscopy, thermogravimetric-differential thermal analyses, Fourier transform infrared spectroscopy and nitrogen adsorption-desorption). It was found that not only the organic template could be completely removed but also the morphology and topology structure of MCM-22 precursor was well preserved after H₂O₂ treatment. Novel zeolite material ITQ-2-like presented relatively ordered cascaded layers in a face-to-face orientation along the c-axis and exhibited different physicochemical properties in comparison with ITQ-2 and MCM-22 prepared from the same precursor. Moreover, the catalytic behaviour and pore roles of three kinds of Mo-containing catalysts of ITQ-2-like, MCM-22 and ITQ-2 were investigated in the reaction of methane aromatization.     

One-pot cascade reactions catalyzed by acid–base mesoporous MCM-41 materials

Acid–base bifunctional mesoporous materials (AB-MCM-41) with aminopropyl and propanesulfonic acid in the same mesoporous material have been synthesized by two different methods: postsynthetic grafting and direct synthesis. AB-MCM-41-g was gained by the modification of SO₃H-MCM-41 surfaces with organic amine functional groups, while AB-MCM-41-co was prepared through co-condensation of trialkoxyorganosilanes with tetraethyl orthosilicate. The bifunctional samples possess hexagonal arrays of uniform pores, large surface area, high pore volume and excellent acid–basic properties. One-pot acid–base cascade reactions were wonderfully achieved in the presence of the efficient acid–base catalysts, which demonstrate the coexistence of acid and base sites in the same material. In addition, the AB-MCM-41-g possesses higher activity for one-pot deacetalization–Knoevenagel and deacetalization–nitroaldol (Henry) reactions in contrast to AB-MCM41-co and this outcome is achieved under simpler synthetic conditions utilizing less time and less material.     

Partial Oxidation of Isobutane over Vanadium Phosphorus Oxides

A series of vanadium phosphorus oxides (VPO) were prepared by using dodecyl amine as surfactant and tested for the partial oxidation of isobutane and isobutene. Characterization results showed that their structure and properties depend on the content of dodecyl amine. Catalytic tests showed that relatively high isobutane conversion and desired product selectivity can be achieved over a proper dodecyl amine doping VPO catalyst. It is also found that higher isobutane conversion can be achieved over V⁴⁺-containing phases as compared to V⁵⁺-containing phases, while proper surface V⁵⁺/V⁴⁺ ratio may be propitious to obtain high selectivity to methacrylic acid for the selective oxidation of isobutane. In addition, the content of dodecyl amine in the preparation of the VPO catalysts appears to be more important in determining the surface P/V ratio of the catalysts.     

自适应混合注意力深度跨模态哈希

针对现有哈希方法在特征学习过程中无法区分各区域特征信息的重要程度和不能充分利用标签信息来深度挖掘模态间相关性的问题,提出了自适应混合注意力深度跨模态哈希检索（AHAH）模型。首先,通过自主学习得到的权重将通道注意力和空间注意力有机结合来强化对特征图中相关目标区域的关注度,同时弱化对不相关目标区域的关注度;其次,通过对模态标签进行统计分析,并使用所提出的相似度计算方法将相似度量化为0～1的数字以更精细地表示模态间的相似性。在4个常用的数据集MIRFLICKR-25K、NUS-WIDE、MSCOCO和IAPR TC-12上,当哈希码长度为16 bit时,与最先进的方法多标签语义保留哈希（MLSPH）相比,所提方法的检索平均准确率均值（mAP）分别提高了2.25%、1.75%、6.8%和2.15%。此外,消融实验和效率分析也证明了所提方法的有效性。     

Synthesis,characterization and catalytic activity of acid–base bifunctional materials through protection of amino groups

Acid–base bifunctional mesoporous material SO₃H-SBA-15-NH₂ was successfully synthesized under low acidic medium through protection of amino groups. X-ray diffraction (XRD), N₂ adsorption–desorption, transmission electron micrographs (TEM), back titration, ¹³C magic-angle spinning (MAS) NMR and ²⁹Si magic-angle spinning (MAS) NMR were employed to characterize the synthesized materials. The obtained bifunctional material was tested for aldol condensation reaction between acetone and 4-nitrobenzaldehyde. Compared with monofunctional catalysts of SO₃H-SBA-15 and SBA-15-NH₂, the bifunctional sample of SO₃H-SBA-15-NH₂ containing amine and sulfonic acid groups exhibited excellent acid–basic properties, which make it possess high activity for the aldol condensation.     

复合配筋管桩抗震性能试验研究

传统PHC管桩在地震作用下表现出脆性破坏特征,限制了其使用范围。已有室内试验研究结果表明,通过在PHC管桩中加入非预应力钢筋形成复合配筋管桩可提高其抗震性能。目前针对管桩破坏机理以及抗震性能的研究,主要采用室内模型试验或振动台试验,未能充分考虑实际工程中桩的受力条件和土体的作用。为研究复合配筋管桩的抗震性能,在软土地区对PHC管桩和复合配筋管桩进行了现场足尺抗震性能试验研究。试验比较了常规管桩以及掺入不同含量非预应力钢筋的复合配筋管桩的滞回曲线、骨架曲线、延性系数、曲率分布等数据,分析复合配筋管桩的抗震性能。研究结果表明：与PHC管桩相比,复合配筋管桩的抗震性能得到明显改善,且对于提高管桩延性来说,存在最优的非预应力筋配筋率。     

对再生沥青进行改性的可行性分析

目前，对老化沥青再生过程中，其低温性能恢复的较差。结合普通沥青改性的思路，从理论上分析了对再生沥青进行改性的可行性，对添加不同改性剂的再生沥青的性能进行了试验验证。结果表明：对再生沥青进行改性处理是可行的，TPS改性剂在改善再生沥青其他性能的同时，可以明显提高再生沥青的低温延度，表现出良好的改性效果。     

Synthesis of Mo/IM-5 catalyst and its catalytic behavior in methane non-oxidative aromatization

A Mo-modified catalyst, Mo-IM-5, was prepared for the non-oxidative aromatization of methane, and for comparison, Mo-ZSM-5 was also synthesized for the same reaction. The physical properties and acidities of the samples were characterized by XRD, SEM, BET and IR spectroscopy. Compared with Mo-ZSM-5, the Mo-IM-5 catalyst showed both a higher methane conversion and higher benzene selectivity. In addition, Mo-IM-5 was slightly more stable than Mo-ZSM-5. The catalytic behavior of Mo-IM-5 may be attributed to its unusual two-dimensional 10-member-ring channel system with the character of three-dimensional cavity. Furthermore, the effects of different Si/Al ratios, Mo loadings and temperatures on the catalytic performance of Mo-IM-5 were also investigated.     

我国汽车工业国际竞争力现状分析及发展路径

从产业集中度、企业生产规模、技术水平、劳动生产率和净出口贸易指数等指标,实证分析了我国汽车工业国际竞争力的发展现状;详细剖析了我国汽车工业国际竞争力水平比较低,落后于国外发达国家汽车工业发展水平的原因;并对提高我国汽车工业国际竞争力的路径提出了几点看法与建议.