超细分子筛材料的合成与应用研究进展

综述了近几年超细分子筛的合成与应用方面的研究进展,重点介绍了几种常用且研究较多的分子筛,主要包括Y,ZSM-5,β,Silicalite-1,ZSM-35,MCM-22等分子筛。对超细分子筛的合成方法及其在石化、环保和生物等领域的应用进行了介绍,并对分子筛复合材料的研究及应用的最新动态进行了评述,说明超细分子筛材料的应用领域仍在不断拓宽,超细分子筛复合材料的研究将会成为分子筛材料领域未来的重要发展方向。     

Preparations of nanosized TiO2 in reverse microemulsion and their photocatalytic activity

Nanosized titania sol has been produced by the controlled hydrolysis of titanium tetraisopropoxide (TTIP) in sodium bis(2-ethylhexyl)sulfosuccinate (AOT) reverse micelles. The physical properties, such as surface area, crystallite size and crystallinity according to R and W₀ ratio, have been investigated by TEM, XRD, BET, FT–IR, TGA and DTA. In addition, the photocatalytic decomposition of p-nitrophenol has been studied by using a batch reactor in the presence of UV light in order to compare the photocatalytic activity of prepared nanosized titania. It is shown that the anatase structure appears in the 300–600 °C calcination temperature range and the transformation of anatase into rutile starts above 700 °C. The crystallite size increases with increasing R and W₀ ratio but W₀ ratio shows a stronger effect on the crystallite size than R ratio. In the photocatalytic decomposition of p-nitrophenol, the photocatalytic activity is mainly determined by the crystallinity of titania. In addition, the titania calcined at 500 °C shows the highest activity on the photocatalytic decomposition of p-nitrophenol() and the pure anatase structure.     

Whey Drying on Porous Carriers

Whey is an undurable product. treated very often as a waste which pollutes the natural environment. Whey which is a valuable source of protein, lactose, vitamins and mineral salts should be utilized completely. The present paper is a proposal of whey drying on porous carriers. It is proved experimentally that the proposed drying method guarantees good product quality.     

高喷煤比操作对焦炭劣化的影响

为考查提高喷煤量对焦炭在炉内劣化的影响,在宝钢高炉上进行了风口取样研究.结果表明,喷煤量达到200 kg/t以上时焦炭劣化严重.高炉生产实绩回归显示,焦炭的热性能对高炉透气性的影响比冷强度显著.分析认为焦炭热性能指标CRI、CSR对高炉高煤比操作更重要.借此还提出了提高喷煤量和改善焦炭质量需加强研究的课题.     

A novel deep learning scheme for multi-condition remaining useful life prediction of rolling element bearings

The remaining useful life (RUL) prediction of a rolling element bearing is important for more reasonable maintenance of machinery and equipment. Generally, the information of a failure can hardly be acquired in advance while running and the degradation process varies in terms of different faults. Thus, fault identification is indispensable for a multi-condition RUL prediction, where, however, the fault identification and RUL prediction are separated in most studies. A new hybrid scheme is proposed in this paper for the multi-condition RUL prediction of rolling element bearings. The proposed scheme contains both classification and regression, where the 2D-DCNN based classifier and predictors are built concerning typical fault conditions of a bearing. For the online prediction, the raw signals are spanned in the time-frequency domain and then transferred into images as the input of the scheme. The classifier is used to monitor the vibration of rolling bearings for online fault recognition and excite the corresponding predictor for RUL prediction once a fault is detected. The output from the predictor is amended by the proposed adaptive delay correction method as the final prediction results. A demonstration is performed based on the XJTU-SY datasets and the results are compared with those from the state-of-the-art methods, which proves the superiority of the proposed scheme in improving the accuracy and linearity of RUL prediction. The time cost of the proposed online prediction scheme is also investigated and the results indicate high time effectiveness.     

Corrosion of metals and alloys in mixed gas environments at elevated temperatures

The attack of nickel, cobalt, iron, and alloys of these metals containing chromium and aluminum, by gases containing sulfur-oxygen, carbon-oxygen, and nitrogen-oxygen has been studied at temperatures of 600 and 900°C. The degradation of these metals and alloys was characterized by using standard analytical techniques with emphasis on optical metallography. Three types of accelerated degradation were identified for the attack of alloys by gases containing another oxidant in addition to oxygen. One type of degradation occurred because of the formation of reaction products composed of mixtures of phases involving both of the oxidants. Another type resulted from the reaction of second oxidant phases with oxygen. The third form of degradation involved the development of less protective phases due to thermodynamic instabilities. Thermodynamic stability diagrams are used to help account for the effects produced by different elements in the alloys.     

Investigations of surface degradation of high‐density polyethylene materials resulting from tracking,using physicochemical analysis

In the present work tracking phenomena were studied with high‐density polyethylene (HDPE) materials under dc voltage, with NH₄Cl and acid rain as contaminants. It was determined that the tracking time of the material depends on the conductivity and flow rate of the contaminant. Furthermore, physicochemical analysis by wide‐angle X‐ray diffraction studies, differential scanning calorimetry, and luminescence spectroscopy was carried out, whereupon it was concluded that the tracking process is a surface‐degradation process. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2843–2849, 2002; DOI 10.1002/app.10260     

NIT-Ph-p-BEN氮氧自由基的制备及催化降解性

以对醛基苯甲酸为原料，通过醛酸与2,3-二甲基-2,3-二羟胺基丁烷缩合，再经NaIO4氧化最终制得4-(4,4,5,5-四甲基-1,3-二氧化物)咪唑基-1-苯甲酸（NIT-Ph-p-BEN氮氧自由基）。采用FTIR、UV、ERP（电子顺磁共振波谱仪）和元素分析等对其结构进行表征；通过催化降解废水中有机染料甲基橙、甲基蓝和罗丹明B对其催化活性进行了评估。结果表明，当甲基橙、甲基蓝和罗丹明B浓度为15 mg/L，NIT-Ph-p-BEN质量浓度为0.15 g/L，H2O2浓度为30 mmol/L时，NIT-Ph-p-BEN对甲基橙有更好的催化降解性，仅在1 h内甲基橙的降解率达到94.26%。此外，反应机理表明，H2O2有助于实现NIT-Ph-p-BEN自由基的再生和循环利用。     

纤维素科学与技术研究进展

本文综述纤维素科学与技术的研究进展。阐述了纤维素结构、纤维素的合成、纤维素液晶、功能纤维素、纤维素溶剂、纤维素裂解和纤维素的废物利用等的最新动态。