Titanate nanotubes: preparation, characterization, and application in the detection of dopamine

Titanate nanotubes were successfully synthesized via a hydrothermal process with the assistance of surfactant. These nanotubes with average length of several hundred nanometers and diameter of 10 nm were employed to modify glass carbon electrode and measure dopamine via electrochemistry method. The experiments showed ideal reversibility in cyclic voltammetry, which might be due to the decrease of the overvoltage of the electrode and increase of electron transference. The results illustrated the potential application in the detection of dopamine.     

Geochemical Characteristics of Rare Earth Elements in Intertidal Sediments of Tianjin Coastal Zone

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Antioxidant and Antithrombotic Activities of Rapeseed Peptides

The antioxidant and antithrombotic activities of crude rapeseed peptides (CRPs) and peptide fractions (RP25 and RP55) prepared from aqueous enzymatic extraction (AEE) of rapeseed were determined. The reducing power of RP55 and CRPs was higher than that of RP25 at the same concentrations. Rapeseed peptides exhibited marked antioxidant activities. The median effective dose (ED₅₀) values of CRPs, RP25 and RP55 for α,α-diphenyl-β-picrylhydrazyl (DPPH) radical scavenging were 72, 499 and 41 μg/mL, respectively. The ED₅₀ values for RP25 and RP55 for hydroxyl radicals scavenging were 2.53 and 6.79 mg/mL, respectively while the ED₅₀ values of RP55 and CRPs for inhibition of lipid peroxidation in a liposome model system were 4.06 and 4.69 mg/mL, respectively. The inhibitory effect on lipid oxidation of RP55 was similar to that of ascorbic acid at a concentration of 5.0 mg/mL. A good positive correlation existed between the peptide concentration and antioxidant activity. RP55 generally showed more potent antioxidant activities except for hydroxyl radicals scavenging ability than RP25 and CRPs at the same concentrations, which was thought to relate to the significantly higher contents of hydrophobic amino acid, tannin, and the brown color substances in RP55. Rapeseed peptides possessed marked inhibitory activities on the thrombin-catalyzed coagulation of fibrinogen, however, their inhibitory effects were not comparable to that of heparin.     

按条件更新参数的自校正控制器

本文对具有有界扰动的线性时不变系统提出了一种新的按条件更新参数的自校正控制算 法.算法的特点是它的计算量与典型的自校正调节器不相上下,但却具有跟随的能力,同时还 能保证闭环系统的稳定.文章对采用此法后的系统稳定性、跟随误差的上限和参数估计的 有界性等问题作了详细的理论分析,最后给出了与其它几种方法对比的仿真结果.     

棉花滩水电站施工期洪水预报

棉花滩水电站施工期洪水预报方案，因施工期短，采用了常规方法，而对于支流永定河顶托问题则突破常规，将流域外的永定河水位引入预报体系，建立多元回归预报方程。从还原结果看，解决了顶托影响，还原精度得到了提高。为满足施工要求，洪水预报密切配合施工，针对不同施工阶段，调整预报方案，抓住重点，确保了施工期防洪安全。     

日本新旧文化女装衣身原型样板的结构对比分析

原型是指结构最简单，但能从本质上反映人体重要特征信息，且力求最大覆盖面的基础图形，是服装制作的基础型。以日本成年女子新旧文化衣身原型样板为研究对象，采用定量、定性分析相结合的方法，对两种衣身原型样板的结构要素，即胸围松量、袖窿深、胸宽、背宽、袖窿宽、省位、省量、前后领围线、肩斜度及前后腰节差，进行探讨分析，指出了新、旧衣身原型的优势和劣势，论证了新原型将取代旧原型而被广泛推广的客观事实。     

Optimization of connecting two communication networks subject to a reliability constraint

This paper considers optimization of two networks with a reliability constraint. The objective is to find some links to connect two networks, at a minimal cost, under the constraint that the system reliability of the resultant network is not less than a given level. A decomposition method based on branch and bound is used for solving the problem. In order to speed up the solution procedure, an upper bound on system reliability in terms of node degrees is applied. In particular, when the threshold P_o is large enough, a new algorithm, the cut tree algorithm, can more effectively give an optimal solution.     

The flowability of fine powders in reduced gravity conditions

The extrapolation of Qian’s semi-theoretical relationship for the transition between cohesive and non-cohesive powder fluidization behavior into regions of low gravity is studied and a validation experiment employing fluidization is discussed. The fluidization experiment utilized fine glass and alumina powders in a fluidized bed and was flown onboard NASA’s reduced gravity aircraft. The transition region between cohesive and non-cohesive behavior is determined for the glass and alumina powders at gravity levels of 1.8, 1.0, 0.38, and 0.16 g. The results are compared to Qian’s model and show fair agreement. The fluidization experiment limitations are discussed and a rotating drum experiment that will reduce the experiment uncertainty, provide quantifiable results, and is suitable for flight onboard NASA’s reduced gravity aircraft is proposed. The rotating drum technique determines the characteristic frequency of the powder’s center of area to detect avalanching. The concept is validated by comparing the characteristic frequency obtained from analyzing a cohesive powder to the characteristic frequency obtained from analyzing a flowable powder.