动物源性食品中氟苯尼考残留水平和 分布情况分析

目的分析动物源性食品中氟苯尼考残留水平和分布规律。方法采用超高效液相色谱-串联质谱法进行残留量测定,并借助Excel2010和社会科学统计软件包18.0对测定结果进行分析。结果方法中,以乙腈-水为最佳流动相,以Welch Xtimate C_(18)为最佳色谱柱。不同品种样品中,氟苯尼考平均回收率为80.3%～95.3%,检出限为0.052～0.095μg/kg,定量限为0.150～0.313μg/kg。472批次样品中,氟苯尼考检出率为15.9%,残留量主要为0.1～1.0μg/kg,检出品种以各鲜肉、胗、大肠以及相应的腊制品和蛋类为主。新复极差分析显示,检出品种中鸡蛋残留量不同于其他品种。结论本研究对氟苯尼考残留水平和分布规律进行了分析,可为市民选择提供参考。     

ZigBee网络技术研究综述

ZigBee是一种供移动电子设备使用的短距离、低功耗、低速率的无线通讯技术, 在智能交通、环境监测等许多领域有广泛的应用, 已成为当前的一个研究和应用热点. 对ZigBee网络拓扑结构、路由选择方法和基于网关的ZigBee互连技术进行分析和综述, 提出了ZigBee技术待解决的问题和未来的研究方向.     

Structure deformation of indium oxide from nanoparticles into nanostructured polycrystalline films by in situ thermal radiation treatment

A microstructure deformation of indium oxide (In₂O₃) nanoparticles by an in situ thermal radiation treatment in nitrous oxide plasma was investigated. The In₂O₃ nanoparticles were completely transformed into nanostructured In₂O₃ films upon 10 min of treatment time. The treated In₂O₃ nanoparticle sample showed improvement in crystallinity while maintaining a large surface area of nanostructure morphology. The direct transition optical absorption at higher photon energy and the electrical conductivity of the In₂O₃ nanoparticles were significantly enhanced by the treatment.     

班布特罗对豚鼠实验性哮喘的作用及其机理研究

目的 研究班布特罗对豚鼠实验性哮喘的作用、药效学及药动学特点及作用机制。方法 组胺和卵清蛋白诱发在体豚鼠实验性哮喘模型, 使用豚鼠离体气管片和肺条进行研究。结果 班布特罗剂量依赖性抑制组胺和卵清蛋白诱发的豚鼠哮喘, 班布特罗对豚鼠气管片无松弛作用, 而灌服其后的松弛气管片和肺条血浆呈剂量依赖性, 且对肺条的松弛作用强于气管片。其峰效应出现于给药后4 h 前后, 作用持续24 h 以上。结论 班布特罗作为特布他林的前药对豚鼠实验性哮喘的作用缓和而持久。     

螺旋藻多糖对小鼠移植性肿瘤化疗后造血恢复及相关细胞因子的影响

目的: 研究螺旋藻多糖(polysaccharide fromspirulina platensis, PSP) 对小鼠移植性肿瘤化疗后造血恢复及相关细胞因子的影响。方法: 通过右前肢皮下接种肿瘤细胞形成小鼠移植性实体瘤, 给予PSP 连续灌胃 10 d, d 4 给予环磷酰胺(CTX) 腹腔注射连续 3 d。于 d 11, 分别观察了外周血细胞、骨髓有核细胞及 CFU-S 计数, 用紫外分光光度计检测骨髓DNA 含量, 用双抗体夹心 ELISA 法检测血清中IL-1、IL-3、GM-CSF、TNF 含量。 结果: CTX 可造成明显骨髓抑制, 而 PSP 则提升了外周血细胞、增加了骨髓中有核细胞计数和 DNA 含量以及促进了 CFU-S形成。 此外, PSP 还增加了血清中 IL-1、IL-3、GM-CSF、TNFα含量。结论: PSP 可能通过促进内源性细胞因子的分泌来实现其促进小鼠移植性肿瘤化疗损伤后的造血恢复。     

Investigation of Characteristics of Al2O3/n-In x Ga1−x As (x = 0.53, 0.7, and 1) Metal–Oxide–Semiconductor Structures

The electrical properties of Al₂O₃/n-InGaAs metal–oxide–semiconductor capacitors (MOSCAPs) with In content of 0.53, 0.7, and 1 (InAs) have been investigated. Results show small capacitance–voltage (C–V) frequency dispersion in accumulation (1.70% to 1.85% per decade) for these MOSCAPs, mostly being assigned to border traps in Al₂O₃. With higher In content, shorter minority-carrier response time and smaller C–V hysteresis are observed. The reduction of C–V hysteresis might be related to the reduction of Ga-bearing oxides in Al₂O₃/InGaAs interfaces as indicated by x-ray photoelectron spectroscopy.     

Preparation of superabsorbent based on the graft copolymerization of acrylic acid and acrylamide onto konjac glucomannan and its application in the water retention in soils

A new konjac glucomannan (KGM)-based superabsorbent polymer, KGM-g-poly(acrylic acid-co-acrylamide), was prepared by the free radical grafting solution polymerization of acrylic acid (AA) and acrylamide (AM) monomers onto KGM in the presence of N,N′-methylenebisacrylamide as a crosslinker with potassium persulfate as an initiator. The effects of reaction parameters, including the amount of crosslinking agent and initiator, the weight ratio of both (AA + AM) to KGM and AM to (AA + AM), neutralization degree of AA, bath temperature, and reaction time, on the water absorbency of the superabsorbent were investigated. The Fourier transform infrared spectroscopy was used to characterize the structures of the copolymer. The maximum water absorbency of the optimized product was 650 g/g for distilled water and 70 g/g for a 0.9 wt % aqueous NaCl solution. Furthermore, the water retention of the copolymer in soils was studied. The effect of the copolymers on the aggregate distribution of soils was also evaluated. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

环介导等温扩增技术检测食源性致病菌的研究进展

环介导等温扩增(LAMP)技术是一种新型核酸扩增技术, 该技术在60?65 ℃恒温条件1 h内, 把特异性靶序列扩增到109水平, 具有高特异性、高敏感性、简单、便捷及成本低的特点, 已广泛应用于流行性细菌、病毒的定性定量检测等领域。本研究对LAMP的原理、特性及其应用做一综述, 从而为其在食源性致病菌检测应用中提供理论依据。     

高村排土场泥石流形成的可能性分析及防治措施

排土场是露天矿山发生地质灾害的要害部位，加强排土场安全管理对于矿山安全生产具有重要意义。结合高村排土场现状，对泥石流形成的可能性进行了分析，并对相应的防治措施进行了探讨，对于类似矿山泥石流地质灾害防治有一定的借鉴价值。     

Effect of lithium phosphate on the structural and electrochemical performance of nanocrystalline LiFePO4 cathode material with iron defects

The influence of excessive lithium on the crystal structure, morphology, and electrochemical properties of Fe-deficient Li_xFePO₄ (x = 1.00, 1.02, 1.04, 1.05) cathode material was investigated using co-precipitation and the carbon thermal method. The X-ray diffraction pattern and Rietveld refinement results show that excessive Li⁺ combines with the phosphate group to form Li₃PO₄ rather than occupying the Fe site to form antisite pairs. Benefitting from the intrinsic ion conductivity of lithium phosphate, the lithium diffusion coefficient of Li_xFePO₄ increases. However, the charge transfer impedance (Rct) also increases with increasing Li content due to the presence of Li₃PO₄, a nonconductive phase that can block the electric transfer channel. The biphasic Li_xFePO₄ (x = 1.02) compound shows the best performance. This work suggests an effective and easy way to improve the electrochemical performance by adding excessive Li, which leads to the formation of Li₃PO₄.