Determination of lumped rate coefficients of proteins: Effect of adsorption

The equilibria and kinetics of adsorption of lysozyme and bovine serum albumin on the Fractogel-EMD tentacle-type cation exchanger and the Fractogel-TSK conventional cation exchanger have been studied experimentally by batch stirred-tank method. Adsorption equilibrium data corresponded well to the Langmuir isotherm. For both proteins, the tentacle-type exchanger exhibited a higher binding capacity than the conventional exchanger. This is attributed to the flexibility of the functional groups in the tentacle-type exchanger which enhance optimal electrostatic interactions. The dynamic data were analyzed by a simplified data model which lumped mass transfer resistances and intrinsic adsorption kinetics into a single rate constant. For both proteins, it was found that the tentacle-type exchanger showed a smaller lumped rate coefficient than the conventional exchanger. The difference in the values of the lumped rate coefficients was shown to be due to the influence of nonlinear equilibrium constants rather than due to any difference in rate of adsorption.     

氯醋共聚树脂的官能团化

以氯乙烯—醋酸乙烯酯共聚树脂为原料，经过醇解后与马来酸酐酯化接枝，得到带羧基的改性树脂。探索其原料配比、催化剂用量、反应时间及反应温度对酯化接枝反应的影响．在酯化反应的最佳条件下：温度100℃，催化剂用量为原料的0．8％，原料和马来酸酐的质量比为1：1，得到酸值为14．39mg KOH/g的氯醋多元共聚树脂，同时用红外光谱进行了表征．     

Stability of ferrofluid flow between concentric rotating cylinders with an axial magnetic field

A linear stability analysis for the ferrofluid flow between two concentric rotating cylinders in the presence of an axial magnetic field is implemented in this study. Both of the wide-gap and small-gap cases are considered and the governing equations with respect to three-dimensional disturbances including axisymmetric and non-axisymmetric modes are derived and solved by a direct numerical procedure. A parametric study covering wide ranges of ?, the volume fraction of colloidal particles; ξ, the strength of axial magnetic field; μ, the ratio of angular velocity of the outer cylinder to that of the inner cylinder; and ε, the ratio of radius of the inner cylinder to that of the outer cylinder, is conducted. Results show that the stability characteristics depend heavily on these factors. It is found that the increases of ? and ξ, and decrease of ε tend to stabilize the basic flow for an assigned value of μ. The variations of the onset mode with these parameters are discussed in detail. An example for the practical application of present results is given to help the understanding of stability behaviour of this flow.     

A note on the equivalence between strict optical orthogonal codes and difference triangle sets

Zhang (see IEEE Trans. Commun., vol.47, p.967-973, July 1999) proposed a special family of optical address codes, called strict optical orthogonal codes (S-OOCs), was proposed for fiber-optic code-division multiple-access (FO-CDMA) networks. Such codes can strictly guarantee both cross-correlation and autocorrelation functions constrained to have the value one in fully asynchronous data communications and ultra fast switching. In Zhang's work the theory and designs of S-OOC, plus several examples, comparison tables, and performance analyses were presented. In this article, we set up the equivalence between S-OOC and so-called difference triangle sets (DTS), which have been extensively studied previously. Thus, all the known constructions, bounds, and analyses for DTS can be directly applied to S-OOC.     

Control of structure, morphology and property in electrospun poly(glycolide-co-lactide) non-woven membranes via post-draw treatments

Non-woven biodegradable membranes fabricated by electrospinning have recently attracted a great deal of attention for biomedical applications. In this study, microstructure, morphology and texture of electrospun poly(glycolide-co-lactide) (GA/LA: 90:10, PLA10GA90) non-woven membranes were investigated after post-draw and thermal treatments to tailor the degradation and mechanical properties. As-prepared electrospun PLA10GA90 membranes exhibited a low degree of crystallinity. When annealed at elevated temperatures without drawing, the membrane showed a higher degree of crystallinity with distinct lamellar structure but no overall orientation. The crystal orientation improved significantly when the membrane was drawn and annealed. As the elongation ratio increased, the degree of orientation and the tensile strength were increased. The corresponding tensile retention time was also increased from 2 to 12 days during in vitro degradation. Post-drawn and annealed membranes exhibited a slower degradation rate in the beginning of incubation, but a faster rate after two weeks of degradation when compared to as-spun membranes.     

Effects of excess tellurium on the properties of CdZnTe radiation detectors

Room-temperature radiation detectors have been fabricated on high-resistivity, indium-doped Cd_0.90Zn_0.10Te crystals grown under different amounts of excess Te. The effects of the excess Te on the properties of the detectors are explained by a simple model using only three parameters: the density of Cd vacancies, the density of Te antisites (Te at Cd sites), and the deep level of doubly ionized Te antisites. The best detectors, which can resolve the low-energy Np-L and Te-K peaks as well as Cd and Te escape peaks of ²⁴¹Am, are produced from crystals grown with 1.5% excess Te. The detectors fabricated from crystals grown without excess Te are unable to resolve any characteristic-radiation peaks of ²⁴¹Am and ⁵⁷Co. This result is explained by a model of networked p-type domains in an n-type matrix or vice versa, which is caused by the lack of sufficient deep-level Te antisites. Such conduction-type inhomogeneity causes massive electron and hole trapping. As for the detectors fabricated from Cd_0.90Zn_0.10Te crystals grown with 2% and 3% excess Te, they are able to resolve the ²⁴¹Am 59.5-keV, ⁵⁷Co 122-keV, and ⁵⁷Co 136-keV radiation peaks. However, the full-width at half-maximum (FWHM) values of these peaks are broadened, especially the high-energy ⁵⁷Co peaks. These phenomena are attributed to the hole and, possibly, electron trapping by Cd vacancies and Te antisites, respectively. The result of the analysis indicates that sufficient Te antisites and a low density of carrier traps in Cd_0.90Zn_0.10Te are essential for producing high-quality radiation detectors. In the analysis, it was discovered that most of the excess Te, on the order of 1–2 × 10²⁰ cm⁻³, remain electrically inactive. A possible explanation for this phenomenon is that the excess Te atoms form neutral Te-antisite and Cd-vacancy complexes, such as Te_Cd·(V_Cd)², during the post-growth cooling process.     

Platform level support for high throughput edge applications: the Twin Cities prototype

Even in the face of increasing network bandwidth, there is a desire among service providers to improve network security, availability, and performance. These improvements require increasingly complex computations on network packets. Current networking platforms cannot keep up, leading to less than desired throughput or functionality. Network processors deliver high networking throughput, but not the complex processing capabilities required. High-performance general-purpose processors deliver the complex processing needed, but not the network throughput. Combination platforms that include high-performance general-purpose CPUs and network processors hold the promise of greatly increasing platform performance, enabling desired edge application improvements. This article presents Twin Cities, a heterogeneous multiprocessor research platform we have constructed from a standard IXP1240 platform, a high-volume Intel/spl reg/ Pentium/spl reg/ III processor platform, and custom hardware. This platform provides a high-performance path (high throughput, low latency) between the two processors and presents a shared memory model to the programmer. We motivate and describe the Twin Cities platform, discuss the applications it targets, and present performance measurements.     

A low-noise L-band EDFA with a 1500-nm Raman-pumped dispersion-compensating fiber section

This report presents a low-noise L-band erbium-doped fiber amplifier (EDFA) with a dispersion-compensating Raman amplifier. With an optimized prestage and 1500-nm Raman-pump laser diodes, the proposed EDFA achieved an internal noise figure of less than 4.5 dB over a 33-nm flat gain bandwidth within 0.5 dB at -2 dBm of large signal input power.     

MTBE装置醇烯比测定技术现状与进展

醇烯比是甲基叔丁基醚（MTBE）生产装置的重要控制指标，对MTBE裟置醇烯比的分析技术现状进行了系统综述，包括实验室气相色谱法，在线工业色谱和软测量技术等，详细介绍了这些方法的原理和优缺点。基于以上调研情况和国际在线分析仪表的发展趋势，提出了采用在线近红外光谱方法实时测量醇烯比的技术方案，并给出了实验室模拟在线测量醇烯比的一些近红外试验结果，该方法有望成为解决在线测量醇烯比的理想手段。     

直流电路CAI系统的位图资源设计

阐述了基于VC的直流电路实验仿真系统的位图资源的设计方案,包括位图资源的抽象化、类的创建,位图资源的树形控件的创建,位图资源的创建和导入.介绍了系统的主要功能和使用方法.该系统既节省了教学资源,又提高了教学效率.