Developing fast laboratory screening platform for sulfate dioxide in food by surface-enhanced Raman spectroscopy

基于表面增强拉曼光谱(SERS)的指纹图谱的高能量分辨率,以位于~630; cm~(-1)亚硫酸根的特征峰为定性和定量依据,本文开展了食品中滥用和非法添加二氧化硫的直接检测研究:一种检测流程实现了不同食品基质中二氧化硫的; 高灵敏检测,最低检出浓度达1 mg; kg~(-1)的水平.针对实际样本的传统蒸馏法前处理流程的一些不足以及SERS检测的指纹图谱优势,本文进行了三方面显著改进:; (1)碳酸钙和沸石取代氮气以提高二氧化硫的挥发提取效率; (2)草酸取代盐酸酸化蒸馏溶液,以有效避免挥发性强酸对操作环境的危害;; (3)氢氧化钠溶液代替乙酸铅溶液作为吸收液,以防止二次污染.环境友好、灵敏度高和不受基质干扰等特点使得本方法有望取代经典蒸馏法和比色法,用于食品; 中非法添加二氧化硫类添加剂的快速高效筛查.The direct detection of sulphur dioxide has been realized in various; food matrixes with high sensitivity and high selectivity, on the basis; of the integration of the high energy resolution of the finger-print; spectrum of surface-enhanced Raman spectroscopy and the universal but; easy-on-going pretreatment procedure. The characteristic peak of sulphur; dioxide at ~630 cm~(-1) was applied as the qualitative and quantitative; standard, which displayed a lowest detectable concentration at the 1 mg; kg~(-1) level for the spiked food samples. The key point of the high; sensitivity and selectivity is the effective pretreatment born out of; the standard distillation one, which has been improved in the three; parts. (1) Using CaCO_3 and Zeolite instead of N_2 gas as the bubbling; reagent. (2) Using oxalic acid as the acidic distillation solution to; eliminate the hazards from acid volatilization, such as hydrochloric; acid. (3) Using diluted sodium hydroxide solution as the absorption; reagent instead of lead acetate solution to avoid the secondary; pollution. With the three distinguished advantages of environment; friendly, high sensitivity and free of matrix interference, the proposed; method has great potential to replace the traditional ones for the fast; screening of the illegal or abused sulphur dioxide in food.国家自然科学基金; 福建省高校产学合作项目; 中央高校基本科研业务费专项资

Theoretical and Experimental Study on Fluorescent Static Quenching of Organic Micromolecule Fluorescence Probe by Macrobiological Molecule

现有的荧光猝灭理论的应用混淆了猝灭剂的平衡浓度[Q]与初始浓度[Q]0之间的关系.基于这一问题,本文探讨了生物大分子与有机物小分子探针之间相互作用的静态荧光猝灭理论,推导了相关的表观结合常数K和结合位点数n的数学表达式,及其相关的定量测定关系式.推导结果表明,荧光体的荧光强度与荧光体和猝灭剂之间的相对浓度有直接的关系,在猝灭剂的初始浓度[Q]0远小于荧光体的初始浓度[P]0时,?F与猝灭剂初始浓度[Q]0在一定浓度范围内呈正比;而在猝灭剂的初始浓度[Q]0远大于荧光体的初始浓度[P]0时,lg1F与lg[Q]0呈正比.本文对上述推导结果进行了实验验证,结果表明,理论推导与实验结果相符,克服了现有的荧光猝灭理论存在的不足,不仅建立了静态荧光猝灭法测定生物大分子的更加科学的方法,而且对研究生物大分子与小分子荧光探针之间的相互作用具有一定的指导作用.The initial concentration and equilibrium concentration are usually confused in the application of existing theories of fluorescent static quenching.So in this article,the theory of fluorescent static quenching by the formation of compound of organic micromolecule with macrobiological molecule was studied.The relationship concerning the apparent formation constant K and the reacting locus number n are deduced and discussed,and the formulas of the quantitative determination are also deduced and proved by experiments.The deduced result as follows,⊿F is proportional to the initial concentration of quencher when the initial concentration of quencher is far less than the initial concentration of fluorescence probe,and lg1F is proportional to lg[Q]_0 when the initial concentration of quencher is far higher than the initial concentration of fluorescence probe.The experiment results proved that the theoretical results deduced in this paper are working.To some extent,these theoretical and experimental results overcome the disadvantages of the existing theoretical and experimental results.So these results not only establish a scientific method of quantitative determination,which can really describe the fluorescent static quenching,but also have instructions for the study on the action between micromolecule fluorescence probes and macrobiological molecules

非掺半绝缘磷化铟晶片的制备及其均匀性

对高温退火非掺磷化铟（InP）制备的半绝缘晶片的电学性质和均匀性进行了研究，非掺低阻N型磷化铟晶片分别在纯磷气氛和磷化铁气氛下进行930 ℃、80h退火均可获得半绝缘材料。但在这两种条件下制备的两种50mm半绝缘晶片却呈现出不同的电学性质和均匀性。纯磷气氛下制备的磷化铟片的电阻率和迁移率分别达到10~6Ω·cm和1800cm~2/(V·s)；而在磷化铁气氛下退火获得的半绝缘片的电阻率和迁移率分别高达10~7Ω·cm和3000cm~2/(V·s)以上。对这两种半绝缘片和原生掺铁磷化铟半绝缘片的PL－Mapping结果进一步比较表

一种仿生可控粘附性疏水金表面的制备方法

本发明涉及一种仿生可控粘附性疏水金表面的制备方法，该方法包括以用自然界生物材料为模板，通过软印章技术法和表面化学修饰法相结合，制备出具有可控粘附性的，并与生物原型表面微织构相一致的疏水金表面，采用本发明方法获得的表面微织构是典型的微、纳二元结构。获得了具有荷叶和水稻叶表面正、反形貌的微、纳二元织构的金表面。具有不同仿生微、纳织构的金表面对水滴表现出不同的粘附性，可以用于工程设计和仿生机器人等设计。正形貌微织构的金表面，具有滚动性疏水性质，反形貌的金表面，具有粘附性疏水性质，可作为“机械手”实现微量液滴的无损运输、液体携带材料和生物微量溶液移液管等应用

GaN基激光器的特性

GaN基激光器具有广泛的应用.如何获得平整腔面是蓝宝石衬底上制作GaN激光器的困难之一.通过对解理面的分析和不同衬底厚度时腔面形貌的比较,发现减薄衬底可以有效降低腔面粗糙度.当外延片厚度减薄至50μm时,获得近似镜面的腔面.激光器的测量证实了腔面的改善可以降低阈值电流,增加斜率效率.利用二维光波导模型计算了脊形高度对限制因子和远场分布的影响.计算结果说明,增加脊形高度可以增加限制因子,降低远场纵横比.通过测量具有不同脊形高度的器件,证实了脊形高度增加,阈值电流降低、远场纵横比减小

不同提示条件下的视空间注意脑机制研究

采用干扰"提示-目标"的视觉实验范式,分别以汉字和范围提示不同等级的搜索范围,通过事件相关电位(ERP)技术研究16名青年被试的视觉空间注意脑机制.结果发现,汉字提示的反应时明显长于范围提示,且在外部干扰条件下,范围提示的靶刺激识别速度优势更为突出;同时,范围提示和汉字提示下靶刺激识别的早期调控分别受干扰类型的影响.与范围提示相比,汉字提示下的靶刺激引起后部P1增强和N1抑制以及P2增强,外部干扰时,汉字提示与范围提示的差异不明显,而在内部干扰时,范围提示和汉字提示的差异增大,表明在靶识别难度增加(内部干扰)时,范围提示和汉字提示下的靶刺激消耗的前额叶资源有显著差异,本研究有力地证明了汉字提示与范围提示具有不同的加工机制

一株嗜盐嗜碱硫氧化菌的筛选、鉴定及硫氧化特性

【背景】沼气和天然气等清洁能源中往往会含有一定量的硫化氢,硫化氢的存在不仅污染环境,而且对人类危害很大。【目的】以硫代硫酸钠为唯一硫源从巴丹吉林沙漠盐碱湖岸边沉积物中分离筛选得到一株硫氧化菌BDL05,并研究其硫氧化特性。【方法】通过形态观察、生理生化特征及16S rRNA基因序列分析对硫氧化菌BDL05进行鉴定。【结果】菌株BDL05为革兰氏阴性菌,弧状,其16S rRNA基因序列与Thiomicrospira microaerophila ASL 8-2的相似性达99.8%,将其命名为Thiomicrospira microaerophila BDL05。该菌氧化硫代硫酸盐的最适pH为9.3,最适总钠盐浓度为0.8mol/L,在以硫化钠为硫源的气升式反应器中单质硫的生成率为94.7%,生成速率为3.0 mmol/(L·h)。【结论】菌株Thiomicrospira microaerophila BDL05为嗜盐嗜碱硫氧化菌,其耐盐耐碱性较强,比生长速率快,硫化钠氧化能力较强,是一株在气体生物脱硫方面具有应用价值的菌株