Catalytic activities and properties of mesoporous sulfated Al2O3–ZrO2

Mesoporous sulfated Al₂O₃–ZrO₂ (MSAZ) catalysts with large surface areas and pore volumes after calcination at high temperature (650 °C) and with higher Al₂O₃ content than 20wt% were successfully prepared from a template of block copolymer (P84). The MSAZ catalysts were characterized by X-ray diffraction (XRD), N₂ adsorption, transmission electron microscopy (TEM), ²⁷Al magic-angle spinning nuclear magnetic resonance (MAS NMR), thermogravimetric analysis (TG–DTG), temperature-programmed desorption of ammonia (NH₃-TPD) and infrared spectra (IR) of adsorbed pyridine. It is shown that the resulting mesostructured sulfated Al₂O₃–ZrO₂ samples have a well-developed textural mesoporosity. The number of acid sites present on MSAZ catalysts is higher than that on conventional sulfated zirconia, and the former catalysts are more active than the latter one for various acid-catalyzed reactions.     

Photoelectric conversion of photosynthetic reaction center in multilayered films fabricated by layer-by-layer assembly

Multilayered protein films which contained ordered layers of photosynthetic reaction center (RC) from Rhodobacter Sphaeroides (RS601) were assembled by means of alternate electrostatic adsorption with positively charged poly(diallyldimethylammonium chloride) (PDDA). The assembly of RC was monitored by spectrometry and photocurrent measurement. Linear film growth was observed up to about 20 cycles of adsorption. For the monolayer film, the photocurrent was about 8.5 nA cm⁻². For the multilayered film, the total photocurrent was about 77 nA cm⁻² for the 24-layer RC film, while the average photocurrent increment per adsorption cycle was about 3.2 nA cm⁻². The overall light-to-electricity conversion efficiency for a 24-layer film was about eight times higher than that for the monolayer one. The effects of electrode potential and pH on the photocurrent were also measured to illustrate the light-to-electric converting mechanism.     

基于改进傅里叶描绘子的CBIR系统

在现有的基于傅里叶描绘子的CBIR系统中,为了提高检索速度,一般需要舍去物体轮廓经傅里叶变换后的大部分高频分量.当物体轮廓在细节部分具有较高能量时,此方法不具备有效性.为尽可能保证检索准确率并兼顾检索速度,在原有傅里叶描绘子上进行扩展,避免直接舍去高频分量,引入Fisher判别分析法将描绘子映射到子空间进行降维,并保证...     

端到端冗余流量消除技术的指纹选择算法研究

为了兼顾服务器端的内存消耗和有效性,在分析了现有端到端冗余流量消除技术中的指纹选择算法后,提出了贪婪指纹选择算法。该算法认为两个数据包中相同片段的邻接片段很有可能也是相同的,基于这一原理,邻接片段的指纹也将被选为代表指纹,有效地避免了在服务器端缓存整个数据包,大大减少了服务器端的内存消耗。仿真实验结果表明,该算法与现有的指纹选择算法相比,能够大大减少服务器端和用户终端的内存消耗,同时冗余消除率在10%-50%之间,与现有算法相近,证明了该算法的有效性。     

The Ratip program for relativistic calculations of atomic transition,ionization and recombination properties

During the past decade, the Ratip program has been developed to calculate the electronic structure and properties of atoms and ions. This code, which is now organized as a suite of programs, provides a powerful platform today to generate and evaluate atomic data for open-shell atoms, including level energies and energy shifts, transition probabilities, Auger parameters as well as a variety of excitation, ionization and recombination amplitudes and cross sections. Although the Ratip program focus on properties with just one electron within the continuum, recent emphasis was placed also on second-order processes as well as on the combination of different types of transition amplitudes in order to explore more complex spectra. Here, I present and discuss the (design of the) Ratip program and make available a major part of the code for public use. Selected examples show a few of its possible applications, while reference is made to a much wider range of computations as supported by the program. The Ratip program has been developed as a scalar Fortran 90/95 code and provides a simple make feature which help port the code to different platforms and architectures.Program summaryProgram title: RatipCatalogue identifier: AEMA_v1_0Program summary URL: http://cpc.cs.qub.ac.uk/summaries/AEMA_v1_0.htmlProgram obtainable from: CPC Program Library, Queen?s University, Belfast, N. IrelandLicensing provisions: Standard CPC licence, http://cpc.cs.qub.ac.uk/licence/licence.htmlNo. of lines in distributed program, including test data, etc.: 256 562No. of bytes in distributed program, including test data, etc.: 4 975 979Distribution format: tar.gzProgramming language: ANSI standard Fortran 90/95 and subsequent developmentsComputer: PCs and workstationsOperating system: Suse, Debian and Ubuntu LinuxRAM: Memory requirements strongly depend on the size of the bound-state wave functions, the property considered as well as the special features selected during the computations.Word size: All real variables are parametrized by a selected kind parameter and, thus, can easily be adapted to any required precision as supported by the compiler. Presently, the kind parameter is set to double precision (two 32-bit words) in the module rabs_constant.Classification: 2.1, 2.9Subprograms used:     

9.

将数学建模思想融入数学类主干课程   总被引：8，自引：0，他引：8  

李大潜 《工程数学学报》2005,22(8):3-7

将数学建模的思想融入数学类主干课程这一建议，并不是心血来潮的产物，而是有充分的根据，并已酝酿了相当长的一段时间的。今天，我只想谈一些自己的看法，作一个非常一般性的发言，不妥之处，请大家批评指正。     

10.

Characteristics and durability test of magnesium phosphate cement-based material for rapid repair of concrete   总被引：11，自引：0，他引：11  

Q. Yang  B. Zhu  X. Wu 《Materials and Structures》2000,33(4):229-234

This paper presents some research results on characteristics and durability of magnesium phosphate cement-based material, such as strength, coefficient of thermal expansion, drying shrinkage, corrosion protection, deicer-frost resistance, abrasive resistance and strength loss while soaking in water or 3% NaCl solution. Experimental results indicate that MPB materials posses high deicer-frost resistance, high abrasion resistance and high corrosion protection for reinforcing steel. In addition, the MPB materials have good compatibility and bond with old concrete, and very low drying shrinkage. However, for the MPB materials soaked in water or 3% NaCl solution for a long time, the strengh loss occurs. Laboratory and field studies show that the MPB materials are suitable for rapid repair of concrete structures. especially pavements aiport runways, bridge decks and key municipal roads, etc.     

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将数学建模思想融入数学类主干课程

将数学建模的思想融入数学类主干课程这一建议，并不是心血来潮的产物，而是有充分的根据，并已酝酿了相当长的一段时间的。今天，我只想谈一些自己的看法，作一个非常一般性的发言，不妥之处，请大家批评指正。     

Characteristics and durability test of magnesium phosphate cement-based material for rapid repair of concrete

This paper presents some research results on characteristics and durability of magnesium phosphate cement-based material, such as strength, coefficient of thermal expansion, drying shrinkage, corrosion protection, deicer-frost resistance, abrasive resistance and strength loss while soaking in water or 3% NaCl solution. Experimental results indicate that MPB materials posses high deicer-frost resistance, high abrasion resistance and high corrosion protection for reinforcing steel. In addition, the MPB materials have good compatibility and bond with old concrete, and very low drying shrinkage. However, for the MPB materials soaked in water or 3% NaCl solution for a long time, the strengh loss occurs. Laboratory and field studies show that the MPB materials are suitable for rapid repair of concrete structures. especially pavements aiport runways, bridge decks and key municipal roads, etc.