共查询到17条相似文献,搜索用时 93 毫秒
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基于再沉淀方法制备了一种具有比率荧光发射的纳米水凝胶,适用于检测生理范围的pH值。通过在聚氨酯水凝胶中引入pH值指示剂以及具有共振能量传递关系的荧光染料分子,赋予原本非pH响应和非荧光型的水凝胶以pH探测能力。随着pH值由酸性渐变为碱性,纳米水凝胶的绿色荧光强度逐渐增强,而红色荧光逐渐减弱。所制备的纳米水凝胶由于具有灵敏度高、亲水性好、稳定性好、响应快以及pH值检测范围恰好涵盖了生理pH值范围(pH值6~8)等优点,因此在细胞内pH值探测领域具有广阔应用前景。 相似文献
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细圆管内纳米悬浮液对流换热的实验研究 总被引:1,自引:0,他引:1
实验研究了细圆管内氧化铜纳米颗粒悬浮换热特性。试验段的管径为0.68mm、1.01mm和1.28mm,氧化钢纳米颗粒平均粒径为50um,悬浮液中氧化铜纳米颗粒质量分数分别为0.02,0.04和0.06,分散剂十二烷基苯磺酸钠(SDBS)质量的分数为0.02。为进行对比分析,还测试了水的换热特性。实验结果表明,在所研究的尺寸下,层流时去离子水的努谢尔特数Nu要高于已有液体对流换热关联式计算之值,纳米颗粒悬浮液的对流换热系数高于水的,且纳米颗粒的质量分数越高,悬浮液的对流换热系数越大。随着流动从层流向湍流的转换,强化效果也越明显。 相似文献
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等离子体光谱/质谱中悬浮液进样研究进展 总被引:2,自引:2,他引:0
等离子体光谱/质谱法是无机元素分析主要的分析方法之一,但其通常要求以溶液形式进样.文章在介绍目前几种固体试样直接进样方法的基础上,着重对悬浮液进样等离子体光谱/质谱研究进展进行综述.叙述悬浮液的制备方法及表征,包括球磨法、混合研磨、振动球磨、超声研磨等降低颗粒的方法.通过分散剂、pH调节等方法分散和稳定悬浮液,并就其关系进行阐述.叙述粒度大小分布测量的几种方法:沉降法、光学显微镜法、光透沉降式粒度仪法、激光散射法、扫描或透射电镜法等.讨论悬浮液浓度影响以及校准方法技术:简单水溶液标准校准法、内标法、经验校正系数法、标准加入法、本征内标法、标准悬浮液法.综述了悬浮液进样的有关基础研究和近年悬浮液进样等离子体光谱/质谱分析应用. 相似文献
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利用传统荧光光谱法探讨了在pH=7、9、11、13下, 各为100 nm直径的纳米钻石及纳米硅土(配成0.25 μg/μL悬浮液)表面上与用7.0 mmol/L PPBS配制成不同浓度溶菌酶-蛋白质之吸附反应.获得了溶菌酶在0~1000 mmol/L不同浓度和不同pH值下的吸附反应常数及表面覆盖度.估算得到并讨论不同浓度和不同pH值下附着在纳米颗粒表面上溶菌酶分子的螺旋曲度及构型、每一溶菌酶分子所拥有之表面积大小.两吸附反应系统中,最高的吸附量与最佳的分子构型是在pH=13的环境下.又得到了溶菌酶在约150~250 nmol/L的线性覆盖曲区中及4个pH值范围中,可保持最佳活性及构型情況下,每平米纳米钻石及纳米硅土表面积可负载2和10 mg,每克纳米钻石及纳米硅土表面可承载溶菌酶130与150 mg.在临界浓度下及4个pH值范围中,可配制成最紧密、最大承载的溶菌酶量,每平米纳米钻石及纳米硅土表面积可负载20和55 mg,每克纳米钻石及纳米硅土表面可承載810~1680及580~1100 mg的溶菌酶. 相似文献
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碳纳米粒子悬浮液具有良好的光限幅性质,是一种优良的宽波段光限幅材料。通过热传导方程和米氏散射理论建立了微气泡半径与入射光能量、碳纳米粒子悬浮液散射系数和透过率的理论模型。采用Matlab数值模拟了散射系数随微气泡尺寸因子的变化关系,碳纳米粒子悬浮液光限幅性能随入射光能量的变化规律。研究了气泡尺寸因子、入射激光能量以及波长对碳纳米粒子悬浮液光限幅特性的影响。研究发现当激光能量达到一定值时,微气泡的半径保持恒定,不再随入射激光能量的增加而增加。微气泡尺寸的增大对碳纳米粒子悬浮液的透过率有着显著的影响。同时,碳纳米粒子悬浮液对不同入射光波长和光能表现出不同的光限幅性能。研究结果为实验研究提供了理论指导。 相似文献
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利用紫外-可见(Uv-Vis)光谱和荧光光谱研究了超声波照射激活纳米二氧化硅(SiO2)粒子对牛血清白蛋白(BSA)分子的损伤,并考查了超声波照射时间、纳米SiO2粉末加入量、溶液酸度和超声波照射功率等因素对BSA分子损伤程度的影响.结果表明,对于体系温度为(37.0±0.2)℃和浓度为1.0×10-5mol·-1的BSA溶液,UV-Vis光谱显示,随着超声波照射时间,纳米SiO2粉末加入量,溶液pH值和照射功率的增大呈现出越来越明显的增色效应.然而,BSA溶液的荧光光谱却随着上述因素的增大呈现出越来越明显的猝灭现象.此外,还初步探讨了超声波照射激活纳米siO2粒子对BSA分子损伤的机理,认为是声致发光或高热激发使纳米siO2粒子产生·OH自由基,进而损伤溶液中的BSA分子.这一研究结果对声催化方法应用于临床治疗肿瘤以及纳米药物的开发具有一定的指导意义. 相似文献
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Sonocatalytic degradation of acid red B and rhodamine B catalyzed by nano-sized ZnO powder under ultrasonic irradiation 总被引:1,自引:0,他引:1
Wang J Jiang Z Zhang Z Xie Y Wang X Xing Z Xu R Zhang X 《Ultrasonics sonochemistry》2008,15(5):768-774
Nano-sized ZnO powder was introduced to act as the sonocatalyst after the treatment of high-temperature activation, and the ultrasound of low power was used as an irradiation source to induce nano-sized ZnO powder performing sonocatalytic degradation of acid red B and rhodamine B. At the same time, the effects of operational parameters such as solution pH value, initial concentration of dyestuff and addition amount of nano-sized ZnO powder have been examined in this paper. We found that the degradation ratios of acid red B and rhodamine B in the presence of nano-sized ZnO powder were much higher than that with only ultrasonic irradiation. However, the degradation ratio of acid red B was about two times higher than that of rhodamine B for the initial concentration of 10.0 mg/L, addition amount of 1.0 g/L nano-sized ZnO powder, solution acidity of pH 7.0 and 60 min irradiation experimental condition. The difference of the degradation ratios can be illustrated by the difference of chemical forms of acid red B and rhodamine B in aqueous solution and the surface properties of nano-sized ZnO particles. In addition, the researches on the kinetics of sonocatalytic reactions of acid red B and rhodamine B have also been performed and found to the follow pseudo first-order kinetics. All the experiments indicated that the sonocatalytic method in the presence of nano-sized ZnO powder was an advisable choice for the treatments of non- or low-transparent organic wastewaters in future. 相似文献
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用化学气相沉积法制备了碳纳米管,进行了不同时间的球磨处理。用扫描电镜、拉曼光谱对其形貌和结构进行了表征。对不同球磨条件下的碳纳米管制备成阴极,进行了场致发射特性的测试。结果表明,高能球磨会对碳纳米管的形貌、结构及场致发射性能有明显的影响。球磨时间为0.5~1h时,可以使碳纳半管变短而均匀,且场致发射电性能与未处理时相近,即有低的阈值电场和高的发射电流密度,从而使发射时在阳极上产生的荧光点密度大大增加,发光均匀。但研磨时间过长会改变碳纳半管结构,使其非晶化或石墨化,导致其场致发射性能和显示效果变差。 相似文献
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采用加热回流老化技术制备了系列组成为0.6CeO2-0.4ZrO2的铈锆复合氧化物,通过N2物理吸附、Raman光谱、UV-Vis漫反射光谱等方法对沉淀过程pH值对铈锆复合氧化物结构及储氧性能的影响进行了研究.结果表明,沉淀过程pH值不同,将导致铈锆复合氧化物的组成产生波动,进而影响样品的晶相组成、缺陷性质、结晶程度和孔结构性质.控制沉淀pH值为10.5~11.0,可消除Si的影响,改善铈锆复合氧化物的孔结构,提高相均匀性,提高缺陷浓度,降低结晶度,从而可提高样品的储氧性能. 相似文献
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Cui Liu Zhen Zhou Linling Zou Yuan-Cheng Cao Jun’An Liu Yongjun Lin 《Journal of fluorescence》2016,26(2):451-457
A highly sensitive transgenic protein analysis method was proposed here based on fluorescein diacetate (FDA). First, FDA was prepared by the ball mill to harvest the nano-sized organic particles. Further examines showed that the FDA size can be controlled by the speed of centrifugation which can obtain FDA in well-distributed size. Cy3 antibody immobilization tests showed that the proteins can attach onto the FDA particles while keep bioactivities. FDA and Cry1Ac antibody immunoassay tests showed that when the FDA particle was in 150 nm, the linear range was 0.01 ng/L-30 μg/mL. And it has the lower detection limitation of 0.01 ng/L, which is 100 times more sensitive than the ELISA methods. These results indicate that the FDA related immunoassays are the promising approach in the transgenic analysis. 相似文献
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Nanostructured Fe2CrAl has been prepared by mechanical alloying using a high energy ball mill. The structural and magnetic properties of the as-milled and mechanically alloyed sample annealed in the presence of a magnetic field have been studied by means of X-ray diffractometry, 57Fe Mössbauer spectroscopy and DC magnetization. The observed properties are compared to that of the bulk sample. The magnetic hyperfine fields are related to structural disorder. There is a very good enhancement of bulk magnetic properties in the nano-sized samples, the most notable one being a dramatic increase in the Curie temperature of these samples and are explained in terms of structural disordering and size effect. 相似文献