有机硅氧烷原位,接枝聚合改性丙烯酸树脂研究

介绍了有机硅氧烷原位、接枝聚合改性丙烯酸树脂的方法及改性过程中水、酸、催化剂等的影响。研究结果表明,这二种方法,特别是原位聚合改性,大大提高了丙烯酸树脂的耐热性和耐溶剂性     

羟基聚硅氧烷一步合成的速率研究

以四甲基氢氧化铵为催化剂,八甲基环四硅氧烷为单体,水为封端剂,一步合成羟基聚硅氧烷。采用凝胶渗透色谱(GPC)测定上述一步合成法的转化率,并建立转化率一时间关系曲线的模型函数(Bolzman函数),获得聚合过程中的重要特征参数：最大转化速率rm,极限转化率x(∞)等。研究表明．温度升高,rm加快,x(∞)降低;催化剂浓度增加,rm加快,x(∞)也增加,而转化速率与催化剂浓度在一定的范围内呈l级动力学关系;水浓度增加,rm降低,同时x(∞)也降低。     

Catalytic decomposition of organic anions in alkaline radioactive waste: IV. Oxidation of glycolate with persulfate in the presence of Ru(III)

Oxidation of glycolate ions with Na₂S₂O₈ + RuCl₃ mixture in 0.2 M NaOH was studied by spectrophotometry. Glycolate is oxidizd to oxalate at 20–70°C. The reaction of glycolate with persulfate follows the first-order rate law with respect to [S₂O ₈ ^2? ], weakly depends on the glycolate concentration, and accelerates with increasing the Ru(III) content from 2 × 10^?5 to 1 × 10^?4 M. Further increase in the Ru(III) concentration does not affect the reaction rate. Probable reaction mechanism was considered.     

含醇污水预处理工艺优化

榆林天然气处理厂担负着整个榆林南区生产污水的处理与回注、甲醇再生利用的任务,甲醇再生的质量、数量、污水回注工艺指标等对于周围环境保护、节能降耗有着重要影响。污水预处理工艺是含醇污水处理工艺的关键过程,预处理参数的好坏直接影响含醇污水的甲醇回收效率、污水回注指标和装置的处理能力,通过对预处理药剂加入、工艺操作进行分析、优化,使预处理后的各项参数达到最佳,提高装置处理能力,减少装置的堵塞和腐蚀,延长装置运行时间,使含醇污水处理后的各项指标达到最优化。     

Catalytic decomposition of hydrazine on ruthenium catalysts in nitric acid solutions

The kinetics and stoichiometry of catalytic decomposition of hydrazine on 5% Ru/SiO₂ in nitric acid solutions were studied. The major reaction products are N₂, N₂O, and HN₃. Ammonium ion is not formed. HN₃ is generated owing to the occurrence of a heterogeneous-catalytic redox cycle on the catalyst surface. The influence exerted on the reaction kinetics by reaction mixture composition and temperature was examined. The process scheme was suggested. The hydrazine decomposition on ruthenium catalysts is a structure-sensitive reaction (positive size effect).     

Genome-Wide DNA Methylation Changes between the Superficial and Deep Backfat Tissues of the Pig

Adipose tissue is not only a storage organ involved in fuel metabolism, but also an endocrine organ involved in the regulation of insulin sensitivity, thermogenesis, immunity, and inflammation. There are anatomical, cellular, molecular and physiological differences among adipose tissues deposited in different body sites. However, current understanding of the intrinsic differences between the sub-compartments of the subcutaneous adipose tissue remains rudimentary. Here, we analyzed the genome-wide DNA methylation differences between the porcine superficial and deep backfat tissues using methylated DNA immunoprecipitation combined with high-throughput sequencing. We show that the genes with differentially methylated regions in their promoter are mainly involved in the processes of "lipid metabolism" and "regulation of immune-related cytokines". Compared with the deep backfat tissue, the promoters of genes related to the 'positive regulation of cytokine production' were significantly hypermethylated in the superficial backfat tissue, which reflects the intrinsic functional and metabolic differences between the sub-compartments of the subcutaneous adipose tissue. This study provides epigenetic evidence for functionally relevant methylation differences between different layers of porcine backfat tissues.     

Stability of Pu(VI) and Pu(V) in aqueous formate solutions

The behavior of Pu(VI), Pu(V), and Pu(IV) in K(Li,Na)HCO₂ and HCOOH + Li(Na)HCO₂ solutions was studied by spectrophotometry. Changes in the spectra of a Pu(VI) solution, observed on adding alkali metal formates, suggest formation of Pu(VI) formate complexes. Changes in the absorption spectra of Pu(V), observed with an increase in the concentration of LiHCO₂ or NaHCO₂, suggest the appearance of Pu(V) formate complexes. The absorption spectra of Pu(IV) indicate that, in a wide range of formate concentrations, the composition of the Pu(IV) formate complexes under the examined conditions is constant. The Pu(VI) content in formate solutions decreases at a rate exceeding the rate of the Pu(VI) disappearance in 0.5–2 M HClO₄ under the action of the ²³⁹Pu α-radiation. The tendency of Pu(V) to reduction and disproportionation in formate solutions depends in a complex fashion on the formate ion concentration and kind of the alkali metal. The kinetics of the Pu(V) consumption in HCOOH + Li(Na)HCO₂ solutions was studied. The reaction starts with the formation of a Pu(V) formate complex, which interacts with Pu(V) aqua ions and Pu(V) formate complex to form dimers, with their subsequent protonation and transformation into Pu(VI) and Pu(IV).     

试谈中国现阶段卫浴空间的设计

卫浴间是室内空间中一个与人的关系极为亲密的功能场所。在中国现阶段室内设计的发展过程中存在着卫浴空间存在着形式设计单一化、空间设计模糊化的问题。本文由这两大问题入手进行简要分析,说明卫浴空间的设计必须重视设计的多样性、提高设计的合理性和提倡设计的环保性。     

Results from experimental investigations of the performance of air condensers for steam turbine units

Results from experimental investigations of the model versions of Type ABC GI air condensers are presented, and it is shown that these condensers have better performance characteristics as compared with their analogs that are currently in operation.     

一种层级化的人眼检测方法

为了提高人眼检测算法的鲁棒性和实时性,提出了一种层级化的人眼检测方法.首先,该方法通过融合人脸检测器和肤色模型在图像大范围内进行快速人脸检测.然后,根据人脸面部拓扑结构几何关系的先验知识粗定位人眼得到人眼的粗定位区域.最后通过融合人眼检测器和人眼模板在人眼粗定位区域实现人眼的精确定位.大规模比较实验表明所提出方法能够准确定位人眼,并能够适用于人脸大小和旋转的变化,具有更强的鲁棒性.