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971.
Rodríguez Patino JM Molina Ortiz SE Carrera Sánchez C Rodríguez Niño MR Añón MC 《Journal of colloid and interface science》2003,268(1):50-57
In this paper we present surface dilatational properties of soy globulins (beta-conglycinin, glycinin, and reduced glycinin with 10 mM of dithiothreitol (DTT)) adsorbed onto the air-water interface, as a function of adsorption time. The experiments were performed at constant temperature (20 degrees C), pH (8.0), and ionic strength (0.05 M). The surface rheological parameters were measured as a function of protein concentration (ranging from 1 to 1x10(-3)% wt/wt). We found that the surface dilatational modulus, E, increases, and the phase angle, phi, decreases with time, theta, which may be associated with protein adsorption. These phenomena have been related to protein adsorption, unfolding, and/or protein-protein interactions (at long-term adsorption) as a function of protein concentration in solution. From a rheological point of view, the surface viscoelastic characteristics of soy globulin films adsorbed at the air-water interface are practically elastic. The main conclusion is that the dilatational properties of the adsorbed films depend on the molecular structure of the protein. 相似文献
972.
The fragmentation functions of the pion with distinction between
,
, and
are studied in the Field-Feynman recursive model, by taking into account the flavor structure in the excitation of quark-antiquark pairs by the initial quarks. The obtained analytical results are compatible with the available empirical results. The framework is also extended to predict the fragmentation functions of the kaon with distinction between
,
,
, and
. This work gives a significant modification of the original model, and the predictions can be tested by future experiments on the fragmentation functions of the kaon.Received: 30 January 2003, Revised: 12 June 2003, Published online: 15 August 2003Bo-Qiang Ma: Corresponding author 相似文献
973.
Viorel NiţicĂ 《Israel Journal of Mathematics》2001,126(1):141-156
Letσ: Σ → Σ be a topologically mixing shift of finite type. Letβ: Σ → ? be a continuous function, and σ β be the skew-product ofσ byβ. Assume that σ β has a positive semi-orbit that reaches any upper height, and any lower height. Then, arbitrarilyC 0-close toβ there exists a Hölder mapβ′: Σ → ? such that the skew-product $\sigma _{\beta ^\prime } $ ofσ byβ′ is topologically transitive. 相似文献
974.
975.
为提高头盔式单目微光夜视仪中光学系统的成像质量,并满足夜视仪结构紧凑、质量小的指标要求,提出在微光夜视仪光学系统设计中引入高次项非球面透镜的设计方法。针对具体的头盔式微光夜视仪,根据微光物镜、目镜系统技术参数计算理论,确定该微光夜视仪光学系统的技术参数,应用光学设计软件ZEMX上机调试,并在光学系统设计中引入高次非球面透镜,使物镜系统镜片数由原来的9片减少为6片,目镜系统由原来的9片减少为7片,简化了结构,并提高了成像质量。设计结果表明:在头盔式微光夜视系统中采用非球面透镜可以提高系统成像质量,简化系统结构。 相似文献
976.
977.
针对关键生命线系统,如电网、供水网、供气网、交通网、通信网等的一些共性特征,建立一个普适性的灾害蔓延动力学模型. 这个模型考虑网络结点的自修复功能、灾害蔓延机制和内部随机噪声,并研究自修复因子、延迟时间因子和噪声强度三个重要特征参数对三种网络(随机网络、无标度网络和小世界网络)结点修复率和崩溃结点数的影响. 模拟结果与这些实际生命线系统的特征一致,表明所建立的模型可以有效地模拟生命线系统的灾害演化动力学.
关键词:
复杂网络
生命线系统
灾害蔓延 相似文献
978.
979.
An analytical formula for the average intensity of cosh-Gaussian (ChG) beams diffracted by an aperture in turbulent atmosphere
is derived and some limiting cases are discussed. By using the average intensity formula, some numerical simulation comparisons
are made and some special cases are studied, especially the influences of the ChG beam parameter (Ω0), the propagation distance, the aperture and its size on the average normalized intensity distribution. It is determined
that the evolution properties of the average normalized intensity profile in turbulent atmosphere with aperture are different
not only from those of free space with aperture but also from those in turbulent atmosphere without aperture.
PACS 42.68.Bz; 42.79.Ag; 42.25.Fx 相似文献
980.
Novel Broadband Reflectarray Antenna with Windmill-Shaped Elements for Millimeter-Wave Application 总被引:1,自引:0,他引:1
Hua Li Bing-Zhong Wang Ping Du 《International Journal of Infrared and Millimeter Waves》2007,28(5):339-344
A novel broadband millimeter-wave reflectarray antenna composed of windmill-shaped elements of variable lengths is proposed.
Compared to the conventional single-layer reflectarray elements, the windmill-shaped elements can realize much larger phase
variation range (over 600°), leading to broader bandwidth. Using this technique, a 15°-beam-steering reflectarray operating
at 30 GHz is designed. The computed results demonstrate the agreement of the main beam steering with the design requirement,
and a 1-dB gain bandwidth close to 20% is obtained. The validity of the obtained results is verified by comparing the ones
generated by Ansoft High Frequency Structure Simulator (HFSS) with those produced by Ansoft Designer. The antenna is useful
for millimeter-wave applications.
This work was supported by the National Natural Science Foundation of China (No. 90505001), the High-Tech Research and Development
Program of China (No. 2006AA01Z275), and the Creative Research Group Program of UESTC. 相似文献