三种投加方式化学强化BAF除磷的试验研究

两级曝气生物滤池串联工艺对有机物和氮的去除效果较好,但除磷效果不理想,常采取化学强化除磷的方法来达到排放标准.分别研究了前置、同步、后置铁盐( FeCl3)化学强化BAF进行化学除磷的效果.结果表明,前置除磷效果最好,同步好于后置,但考虑到前置和后置都得增加沉淀池,所以同步强化也是一种较好的方法,能够使出水TP达标.     

通过引入异氰酸酯制备水性硝化棉的动力学研究

将亲水基团引入硝化纤维素分子中是消除硝基涂料VOC含量过高缺陷的重要手段。为获得最佳反应条件,分析了异氰酸酯与硝化纤维素分子反应动力学的特点;通过测定不含催化剂及不同催化剂浓度、不同反应温度下异氰酸酯浓度随时间的变化,配合数学处理,得到了两者反应时的活化能、最佳催化剂浓度、不同条件下的反应速率常数等参数,推导了反应机理。认为异氰酸酯与硝化纤维素反应为二级反应,催化剂的加入可极大提高反应速率,并降低活化能50%。     

Prediction of lysine ubiquitylation with ensemble classifier and feature selection

Ubiquitylation is an important process of post-translational modification. Correct identification of protein lysine ubiquitylation sites is of fundamental importance to understand the molecular mechanism of lysine ubiquitylation in biological systems. This paper develops a novel computational method to effectively identify the lysine ubiquitylation sites based on the ensemble approach. In the proposed method, 468 ubiquitylation sites from 323 proteins retrieved from the Swiss-Prot database were encoded into feature vectors by using four kinds of protein sequences information. An effective feature selection method was then applied to extract informative feature subsets. After different feature subsets were obtained by setting different starting points in the search procedure, they were used to train multiple random forests classifiers and then aggregated into a consensus classifier by majority voting. Evaluated by jackknife tests and independent tests respectively, the accuracy of the proposed predictor reached 76.82% for the training dataset and 79.16% for the test dataset, indicating that this predictor is a useful tool to predict lysine ubiquitylation sites. Furthermore, site-specific feature analysis was performed and it was shown that ubiquitylation is intimately correlated with the features of its surrounding sites in addition to features derived from the lysine site itself. The feature selection method is available upon request.     

Biomorphic silicon/silicon carbide ceramics from birch powder

A novel process has been developed for the fabrication of biomorphic silicon/silicon carbide (Si/SiC) ceramics from birch powder. Fine birch powder was hot-pressed to obtain pre-templates, which were subsequently carbonized to acquire carbon templates, and these were then converted into biomorphic Si/SiC ceramics by liquid silicon infiltration at 1550 °C. The prepared ceramics are characterized by homogeneous microstructure, high density, and superior mechanical properties compared to biomorphic Si/SiC ceramics from birch blocks. Their maximum density has been measured as 3.01 g/cm³. The microstructure is similar to that of conventional reaction-bonded silicon carbide. The Vicker's hardness, flexural strength, elastic modulus, and fracture toughness of the biomorphic Si/SiC were 19.6 ± 2.2 GPa, 388 ± 36 MPa, 364 ± 22 GPa, and 3.5 ± 0.3 MPa m^1/2, respectively. The outstanding mechanical properties of the biomorphic Si/SiC ceramics are assessed to derive from the improved uniform microstructure of the pre-templates made from birch powder.     

Preparation of molecularly imprinted CS membrane for recognizing naringin in aqueous media

A molecularly imprinted membrane (MIM) was prepared in aqueous media using chitosan (CS) as a functional polymer, naringin (NG) as a template molecule by phase-inversion technique. The morphologies of the MIM before and after modification with the porogen (PEG) were observed by SEM. The imprinted membrane showed an excellent performance when sulfuric acid was used as a cross-linking agent at the mass ratio of CS:NG = 15:1. The FT–IR spectra confirmed that the formation of hydrogen bond between functional polymer and template molecules. The NG–CS MIM was used to separate NG from neohesperidin/NG in the aqueous media, and the highest permeation percentage was 11.16% for 8 h.     

Preparation and properties of poly(ether ether ketone) composites reinforced by modified wollastonite grafting with silaneterminated poly(ether ether ketone) oligomers

Silane-terminated poly(ether ether ketone) oligomers were synthesized and grafted onto wollastonite (W) particles. The prepared grafted-wollastonite particles (g-W) were then incorporated into PEEK matrix via melt processing. Properties of the PEEK composites were investigated using differential scanning calorimetry (DSC), universal tester and rheometer. The researchers found the mechanical properties of the PEEK/g-W composites were markedly enhanced, complex viscosity of the PEEK/g-W composites increased, and both the peak crystallization temperature (T _c ) and crystalline fraction (χ _c ) of the PEEK composites with g-W were significant higher compared with those of the PEEK composites with W. It is our belief that these results are due to the strong interaction between the grafted-wollastonite particles and the PEEK matrix.     

锂离子电池锡/碳复合负极材料的制备及电化学性能研究

以二氧化锡和导电碳(Super P)为原料,通过高能球磨,采用高温固相法制得锡/碳复合材料作为锂离子电池负极材料。用XRD、SEM进行表征,并进行有关电化学性能测试,首次放电比容量高达566.4 mAh.g-1,循环性能得到了较大改善。     

水处理工艺中甾体雌激素的去除及控制研究进展

综述了甾体雌激素( SEs)在水处理工艺中的去除及其控制研究进展.文献表明,现有水处理工艺对SEs处理效果不佳,其在水处理工艺中会进一步发生迁移转化.根据SEs的研究进展,目前亟需进行SEs去除条件下的毒性削减技术研究,为确保水质安全提供科学依据和技术指导.     

三甘醇（TEG）清洗在PBT聚合装置中的应用

基于三甘醇（TEG）清洗的工作原理,通过对PBT（聚对苯二甲酸丁二醇酯）聚合装置酯化釜进行TEG清洗操作,摸索清洗所需工艺流程改造、清洗操作参数、准备工作,对使用TEG和1,4-丁二醇（BD）为清洗济的清洗效果进行了比较。PBT酯化釜使用TEG进行热清洗后,产品质量得到了提高,清洗过程的产品降等量得到了降低,装置清洗周...     

在传统与现代之间选择

工笔人物画作为中国画最重要的组成部分,是中国画最早出现的画种,呈现出不同于西方艺术而独具东方品味的人物画科。工笔人物画在其漫长的历史演进中,积淀了一套完整的表现规律和格法,展现出独有的中国画审美特征。工笔人物画的主要特征体现在以下几个方面：首先,重视主体精神的表现,追求一种超物质精神本源和自然具象的束缚;其次是“以形写神”的法则入画,追求缘物寄情,物我交融的“意象”造型观;三是“以线立骨,尚骨气”的主要特征。