Cationic polyelectrolyte/bentonite prepared by ultrasonic technique and its use as adsorbent for Reactive Blue K-GL dye

In this study, the cationic polyelectrolyte polyepicholorohydrin-dimethylamine (EPI-DMA) was intercalated into bentonite using ultrasonic. The structure of EPI-DMA/bentonite and its adsorption of Reactive Blue K-GL (RB K-GL) dye were investigated. Compared with raw bentonite, the EPI-DMA/bentonite had larger interlayer spacing and was more hydrophobic, providing with better surface properties for adsorption. The adsorption of RB K-GL on EPI-DMA/bentonite was described by the adsorption models of Langmuir, Freundlich and Dubinin-Radushkevic. The adsorption kinetics was analyzed using pseudo-first- and second-order kinetic models and intraparticle diffusion model. Results showed that both the intraparticle diffusion and first-order adsorption occur in the initial period of adsorption, and that pseudo-second-order kinetic model was more suitable for describing the whole adsorption process. The reaction rates were also calculated. The changes of free energy, enthalpy and entropy of adsorption were evaluated for the adsorption of RB K-GL onto EPI-DMA/bentonite, suggesting that the adsorption process was spontaneous and exothermic.     

Effects of Fe/Ni Ratio on Microstructure and Properties of FeNiCrAlNb High-Entropy Alloys

Herein, the effects of Fe/Ni ratio on the microstructure, mechanical properties, and corrosion resistance in a 3.5 wt% NaCl solution of Fe_xNi_65−xCr₂₀Al₁₀Nb₅ are investigated systematically. It is found that the phases shifted from the FCC-dominated to the BCC-dominated with the molar ratio of the Fe/Ni increased. The strength of Fe_xNi_65−xCr₂₀Al₁₀Nb₅ increases with the molar ratio of Fe/Ni further increased, while the plasticity decreases. The yield strength reaches 1,653 MPa at x = 45. The alloy exhibits the best corrosion resistance when x = 35 which is attributed to the dominant FCC phases in the dendritic region.     

运动平台上多基地雷达接收机中频率误差对测距的影响

针对运动平台上的多基地雷达,定量分析了接收机中频综与发射机工作频率之间的误差对测距的影响。     

大肠埃希氏菌ERIC-PCR指纹图谱构建及贝类污染微生物源示踪

目的:采用rep-PCR的ERIC引物(ERIC-PCR)构建象山港周边粪污染指示因子大肠埃希氏菌(E.coli)的DNA指纹图谱库,并根据所建DNA指纹图谱库对贝类产品污染进行微生物源示踪(Microbial Source Tracking,MST)。方法:在选定的贝类养殖区域周边的畜禽养殖场采集鸡、鸭、鹅和猪来源的粪样,从已知来源的粪样中分离鉴定大肠埃希氏菌并构建ERIC-PCR指纹图谱库;用InfoQuestFPTM(Bio-rad)软件对指纹图进行聚类分析与判别分析,并对分离于象山港滩涂贝类及养殖水域的未知来源大肠埃希氏菌进行多维尺度(MDS)的分析,判别其可能来源。结果:216株不同粪样来源的大肠埃希氏菌经聚类分析后得到37种聚类;经Jackknife分析,正确判别率分别为猪源91.7%,鸡源76.9%,鸭源100%和鹅源94.4%;此外,分离自贝样和水样的未知来源得到有效区分,区分率达80.0%(12/15),正确判别率为78.8%。结论:建立的ERIC-PCR微生物源示踪方法能区分贝类和水体中指示菌的不同来源,该方法的建立为查找贝类粪便污染可能的来源以及确保贝类产品安全提供了新技术。     

金线鱼鱼鳞营养成分的分析研究

用等离子体发射光谱法、气相色谱-质谱联用分析法和高效液相色谱法分别测定了金线鱼鱼鳞中9种元素、6种脂肪酸和15种氨基酸的含量。结果表明:金线鱼鱼鳞中含有丰富且对人体健康有益的元素;含5种必需氨基酸(苏氨酸、赖氨酸、苯丙氨酸、亮氨酸、异亮氨酸);所含的脂肪酸主要是十六脂肪酸(棕榈酸)和9-十八碳烯酸(油酸),其含量分别占脂肪酸总含量的30.16%和15.17%;金线鱼鱼鳞营养价值高,具有开发利用价值。     

浅析江苏省高新技术企业申报与立项

通过对2002年-2006年江苏省高新技术企业的申报与立项情况的分析，指出了江苏省高新技术企业发展中存在的主要不足并提出了相应的对策及建议。     

基于田口方法的GaAs基片化学机械抛光加工工艺研究

为获得超平滑的GaAs基片表面,以H2O2、CeO2和NH4OH溶液为抛光液,采用化学机械抛光方法对GaAs基片进行了超精密加工.采用田口方法对氧化剂H2O2含量、碱性溶液NH4OH含量、加工载荷、抛光盘转速4个重要影响因素进行了优化设计,得到以表面粗糙度和材料去除率为评价条件的综合最优抛光参数.结果表明,当H2O2质量分数为 30%,NH4OH质量分数为0.08%,加工载荷为18 kPa,抛光盘转速为30 r/min时,可以获得表面粗糙度和材料去除率综合最优的GaAs基片抛光效率.     

Regulation of presynaptic NMDA responses by external and intracellular pH changes at developing neuromuscular synapses

NMDA receptors play important roles in synaptic plasticity and neuronal development. The functions of NMDA receptors are modulated by many endogenous substances, such as external pH (pHe), as well as second messenger systems. In the present study, the nerve-muscle cocultures of Xenopus embryos were used to investigate the effects of both external and intracellular pH (pHi) changes on the functional responses of presynaptic NMDA receptors. Spontaneous synaptic currents (SSCs) were recorded from innervated myocyte using whole-cell recordings. Local perfusion of NMDA at synaptic regions increased the SSC frequency via the activation of presynaptic NMDA receptors. A decrease in pHe from 7.6 to 6.6 reduced NMDA responses to 23% of the control, and an increase in pHe from 7.6 to 8.6 potentiated the NMDA responses in increasing SSC frequency. The effect of NMDA on intracellular Ca2+ concentration ([Ca2+]i) was also affected by pHe changes: external acidification inhibited and alkalinization potentiated [Ca2+]i increases induced by NMDA. Intracellular pH changes of single soma were measured by ratio fluorometric method using 2,7-bis (carboxyethyl)-5, 6-carboxyfluorescein (BCECF). Cytosolic acidification was used in which NaCl in Ringer's solution was replaced with weak organic acids. Acetate and propionate but not methylsulfate substitution caused intracellular acidification and potentiated NMDA responses in increasing SSC frequency, intracellular free Ca2+ concentration, and NMDA-induced currents. On the other hand, cytosolic alkalinization with NH4Cl did not significantly affect these NMDA responses. These results suggest that the functions of NMDA receptors are modulated by both pHe and pHi changes, which may occur in some physiological or pathological conditions.     

如何有效地进行供应商开发

笔者结合了大连三洋制冷在供应商管理工作中的实际运行经验，分析了供应商开发的步骤，阐述了供应商开发的基本准则，突出源头控制作用，将产品的质量、成本、交货期以及服务进行了有效的延伸，为企业应对激烈的市场变化，保持自身的竞争优势，提供了有益的借鉴。