血红细胞时滞模型的谱及其解的结构

研究一个带有时滞的血红细胞模型的解展开问题.对模型在平衡点处线性化,并利用泛函分析方法,将线性化模型写成抽象发展方程.借助半群理论证明了方程的适定性.对系统算子细致的谱分析,得到了本征值的渐近表达式.通过对算子的Riesz谱投影范数的渐近估计,证明系统的本征向量不能构成状态空间的基,但我们仍给出了方程的解在平衡点附近按照本征向量的的渐近展开.     

A chemostat model of resource competition and allelopathy

Presented is a chemostat model in which one microbial population excretes a poison that increases the mortality of another, with toxin production increasing as the growth rate of the toxic species decreases. The model is intended to explore the role of allelopathy in blooms of harmful algae, such as red tide (Karenia brevis) and golden algae (Prymnesium parvum). This study introduces the model and its biological basis, and proceeds to the analysis of its asymptotic states. All theoretical results are supported by a set of numerical simulations. A discussion of biological conclusions and similarities to other mathematical models is also presented.     

Hydrodynamic cavitation coupled with zero-valent iron produces radical sulfate radicals by sulfite activation to degrade direct red 83

In the present research, hydrodynamic cavitation (HC) and zero-valent iron (ZVI) were used to generate sulfate radicals through sulfite activation as a new source of sulfate for the efficient degradation of Direct Red 83 (DR83). A systematic analysis was carried out to examine the effects of operational parameters, including the pH of the solution, the doses of ZVI and sulfite salts, and the composition of the mixed media. Based on the results, the degradation efficiency of HC/ZVI/sulfite is highly dependent upon the pH of the solution and the dosage of both ZVI and sulfite. Degradation efficiency decreased significantly with increasing solution pH due to a lower corrosion rate for ZVI at high pH. The corrosion rate of ZVI can be accelerated by releasing Fe²⁺ ions in an acid medium, reducing the concentration of radicals generated even though ZVI is solid/originally non-soluble in water. The degradation efficiency of the HC/ZVI/sulfite process (95.54 % + 2.87%) was found to be significantly higher under optimal conditions than either of the individual processes (<6% for ZVI and sulfite and 68.21±3.41% for HC). Based on the first-order kinetic model, the HC/ZVI/sulfite process has the highest degradation constant of 0.035±0.002 min⁻¹. The contribution of radicals to the degradation of DR83 by the HC/ZVI/sulfite process was 78.92%, while the contribution of SO₄^•− and ^•OH radicals was 51.57% and 48.43%, respectively. In the presence of HCO₃⁻ and CO₃²⁻ ions, DR83 degradation is retarded, whereas SO₄²⁻ and Cl⁻ ions promote degradation. To summarise, the HC/ZVI/sulfite treatment can be viewed as an innovative and promising method of treating recalcitrant textile wastewater.     

三维荧光光谱-小波变换-粒子群算法联用快速识别测定浮游藻群落组成方法的研究

利用三维荧光光谱(EEMs)技术测定了实验室培养的分属5个门13个属的17种中国近海常见赤潮藻的荧光性质,通过db7二维小波变换提取赤潮藻三维荧光光谱的特征参量,采用系统聚类法构建荧光特征标准谱库,并利用多元线性回归辅以粒子群算法进行参数估计建立识别技术,实现了赤潮藻在门、属水平上的识别测定。测定样品中:赤潮藻纯种培养体在门、属水平上的平均识别正确率分别为96.1%和73.6%;对于优势度分别为60%,75%,80%,90%的赤潮藻模拟混合样品,优势藻在门水平上的平均识别正确率分别为86.7%,96.9%,98.7%,99.4%,识别相对含量分别为62.6%,72.7%,76.0%,81.6%;优势藻在属水平上的平均识别正确率分别为51.0%,68.9%,72.0%,78.8%;对于优势度达75%的赤潮藻实际混合样品,优势藻在门、属水平上的平均识别正确率分别为99.4%和75.9%。将所建技术用于围隔实验水样和现场调查采集水样进行分析,有效实现了浮游藻群落组成的识别测定,尤其是硅藻和甲藻的分类识别。     

Sonoelectrochemical oxidation for decolorization of Reactive Red 195

The decolorization and degradation of Reactive Red 195 (RR 195) is studied using sonoelectrochemical and electrochemical oxidation. Sonoelectrochemical oxidation was found to be more efficient than electrochemical oxidation. The efficiency of decolorization was found to be 91% and 99% in the case of electrochemical and sonoelectrochemical process, respectively. The effect of different supporting electrolytes and ultrasonic power on decolorization and COD removal has been studied. The decolorization was found to be maximum in the KCl and NaCl as electrolytes. The color removal decreased with increasing ultrasonic power. Response surface methodology was used to assess optimal condition for decolorization and COD removal of RR 195. A Central Composite Design in five most important operating variables; current density, electrolyte concentration, dye concentration, time and sonication power was employed for experimental design and optimization of results. The significance of independent variables and their interactions were tested by means of the analysis of variance with 95% confidence limits. There was good agreement between the experimental and predicated values. Sonoelectrochemical degradation was found to be efficient in decolorizing simulated textile effluent. The results show that ultrasound was significantly enhanced in the electrochemical oxidation.     

A Novel Nitric Oxide Cellular Biosensor Based on Red Blood Cells Immobilized on Gold Nanoparticles

Abstract

We have developed a novel nitric oxide (NO) cellular biosensor based upon the immobilization of red blood cells (RBCs) onto nanometer‐size colloidal gold that is attached to an electrochemically pretreated glassy carbon electrode via the bridging of an ethylenediamine monolayer. The biosensor has been characterized by atomic force microscopy (AFM), scanning electron microscopy (SEM), and electrochemistry. The immobilized RBCs display an excellent electrocatalytic response to nitric oxide. The electrocatalytic currents are proportional to the NO concentration in the range from 1.0×10^–8 to 1.0×10^–6 M and the detection limit is as low as 5.0×10^–9 M (S/N=3). Furthermore, the biosensor is very stable and relatively free of potential interference.     

Fourier Transform Infrared Spectroscopy Evaluation of Commercial Room Temperature Vulcanized Silicones

Abstract

Increased use of instrumental analysis techniques is being required for critical quality control of polymeric raw materials used in the Thermal Protection System of Space Shuttl's External Fuel Tank. This paper is concerned with the FTIR evaluation of commercial room temperature vulcanized silicones. These silicone materials are two-component systems and the methodology developed is a comparison technique, and is performed via a computerized difference spectroscopy approach. A reference material is used as standard, and the subsequent lots are compared with the standard to assess their acceptability and conformance to specificatio. Results obtained so far indicated that the FTIR technique is a viable quality control procedure for use as a routine receiving/acceptance test.     

Optical grating recording in highly organized thin films of Disperse Red 1

Optical grating recording with submicrometer spatial resolution, which can handle grey-level patterns, has been investigated in photochromic material made of Disperse Red 1 (DR1) molecules vacuum-deposited on a glass substrate. Holographic gratings of periods Λ within the range of 0.6 μm - 12 μm were recorded by 514.5 nm light from cw Ar⁺ laser using a degenerate two-wave mixing technique. Despite the very small DR1 layer thickness (∼ 0.1 μm), the diffraction efficiency measured in a Raman-Nath scattering regime reached 2 %. The obtained amplitude gratings were analysed with an optical microscope and Fourier transforms. Grating profiles were analysed in relation to exposure conditions and in correlation with molecular organisation. Polarising microscopy studies revealed the presence of light-induced optical anisotropy. Following that, we have checked the possibility of polarisation-sensitive recording in this medium.