纳米水离子杀灭病毒效果及作用机理探究

研究纳米水离子对不同病毒的杀灭效果及作用机理。选择包膜病毒(甲型流感病毒A/Hong Kong/1/1968 H_(3)N_(2)、人普通冠状病毒HCoV-229E)及非包膜病毒(鼻病毒HRV16和肠道病毒EV71)作为试验毒株,研究纳米水离子对空间中和物表上病毒的杀灭效果,同时结合倒置荧光显微镜和流式细胞仪等进一步分析纳米水离子杀灭病毒的作用机理。结果表明:纳米水离子在1m^(3)舱内作用2h,对H_(3)N_(2)、229E、HRV16和EV71的杀灭效果分别为99.41%、99.99%、99.21%、98.94%;对距离为10cm的玻片上病毒的灭活效果随时间延长而加强,作用4h时,对H3N2、229E、HRV16和EV71灭活对数值分别为3.84、2.25、4.17、4.67;从流式细胞仪的观察结果来看,试验组与对照组病毒在后续吸附细胞的过程中并未体现出明显的差异,蚀斑形成法则显示纳米水离子对H3N2形成的蚀斑大小有影响,对HRV16形成的蚀斑大小无影响。结论:可推断纳米水离子不阻断病毒粒子吸附到细胞受体上,其对病毒的杀灭效果更可能作用于病毒感染的后续事件中,如病毒与细胞膜的融合、脱壳及复制等的生命周期事件中,其杀灭效果是有多重原理共同作用的。

纳米水离子对霉菌的消毒效果及机理研究

研究纳米水离子对室内常见霉菌的消毒效果及作用机理。选择黑曲霉、草本枝孢霉、产黄青霉作为试验菌种,研究纳米水离子对空间和物表霉菌的消毒效果,并结合扫描电镜和高通量RNA测序技术(RNASeq),进一步探索纳米水离子对霉菌的消毒作用机理。结果表明,纳米水离子作用2h,对空气中黑曲霉、产黄青霉和草本枝孢霉的杀灭率分别为94.15%、94.14%和92.89%;作用24h后,对物体表面上的黑曲霉、产黄青霉和草本枝孢霉的杀灭率分别为99.10%、99.06%和99.12%。在扫描电镜下观察发现作用后的霉菌孢子萌发的菌丝产生了破损、畸形等损伤。对作用后的霉菌菌丝进行RNA-Seq后富集分析,发现纳米水离子主要从膜结构和代谢通路上对霉菌的活性产生影响。结论:纳米水离子可通过破坏霉菌孢子的膜结构和改变其代谢通路的方式,达到对霉菌的消毒效果。

纳米水离子对异味去除效果的实验研究

本实验分别选用单一化合物异戊酸和混合物烟臭作为异味源,以官能法作为烟臭净化实验的测定及评价方法,以三点比较式臭袋法作为异戊酸净化实验的测定及评价方法,进行了自主研制的水离子发生装置的异味净化效果实验研究。实验结果表明:纳米水离子对烟臭和异戊酸均具有明显的净化效果,为水离子新型异味净化装置的研发提供依据。

多针-板直流放电纳米水离子发生器电极结构研究

等离子体是由电子,离子,自由基和中性粒子组成的准电中性流体,因其处于某种特殊的活化状态因而具有一定的净化效果。作为等离子体净化的分支,纳米水离子净化过程中形成的微小液滴包裹着水离子并延长了其存活时间,使得空间内存在更多的活性物质OH*自由基,加速了物质的降解过程。本文选取NH3作为被净化物质,利用异味净化实验台测试多组不同多针-板放电结构下纳米水离子发生器的净化效果,从而探究针板间距,针尖数量及排列方式参数对净化效果产生的影响。实验前利用Comsol软件对空间静电场进行模拟,根据模拟结果进行实验设计,同时将实验结果与模拟结果进行对比,得出结构参数对电场强度与对净化效果影响的相似与不同之处。

Influence of Nonionic Surfactant Addition on Drag Reduction of Water Based Nanofluid in a Small Diameter Pipe

The goal of this research was to determine the impact of nonionic surfactants on drag reduction effect in water and metal oxide nanofluid. Two nonionic surfactants （Rokacet 07 and Rokanol KT） and copper（II） oxide wa- ter-based nanofluid were examined. Friction factors in a 4 mm diameter pipe for the Reynolds number between 8000 and 50000 were determined. Results showed that addition of nonionic surfactants caused the decrease of fric- tion factor in water and nanofluid. The drag reduction effect was similar in both cases. Presence of nanoparticles in the system has no great influence on drag reduction effect.

Selective removal of heavy metal ions from aqueous solutions with surface functionalized silica nanoparticles by different functional groups

The industrial silica fume pretreated by nitric acid at 80 °C was re-used in this work. Then, the obtained silica nanoparticles were surface functionalized by silane coupling agents, such as(3-Mercaptopropyl) triethoxysilane(MPTES) and(3-Amincpropyl) trithoxysilane(APTES). Some further modifications were studied by chloroaceetyl choride and 1,8-Diaminoaphalene for amino modified silica. The surface functionalized silica nanoparticles were characterized by Fourier transform infrared(FI-IR) and X-ray photoelectron spectroscopy(XPS). The prepared adsorbent of surface functionalized silica nanoparticles with differential function groups were investigated in the selective adsorption about Pb2+, Cu2+, Hg2+, Cd2+ and Zn2+ions in aqueous solutions. The results show that the(3-Mercaptopropyl) triethoxysilane functionalized silica nanoparticles(SiO2-MPTES) play an important role in the selective adsorption of Cu2+ and Hg2+, the(3-Amincpropyl) trithoxysilane(APTES) functionalized silica nanoparticles(SiO2-APTES) exhibited maximum removal efficiency towards Pb2+ and Hg2+, the 1,8-Diaminoaphalene functionalized silica nanoparticles was excellent for removal of Hg2+ at room temperature, respectively.

Simulation study on dynamics of A- to B-form transition in aqueous DNA solution:Effect of alkali metal counterions

DNA and its conformational transition can be used to design nanometer-scale structures, nano-tweezers and nanomechanical devices. Experiments and molecular simulations have been used to study the concentration effect on the A-DNA→B-DNA conformational transition, but a systematical investigation on counterion effect on the dynamics of this transition has not been reported up to now. In present work, restrained and unrestrained molecular dynamics （MD） simulations have been performed to characterize the stability of DNA conformations and the dynamics of A-DNA→B-DNA transitions in aqueous solutions with different alkali metal counterions. The DNA duplex d（CGCGAATTCGCG）2, coion Cl- and counterions Li＋, Na＋, K＋, Rb＋ and Cs~ as well as water molecule were considered using the PARM99 force field in the AMBER8 package. It was found that B-form DNA is more stable than A-form DNA in aqueous electrolyte solutions with different alkali metal counterions. In- creasing KCI concentration in solution hinders the A-DNA^B-DNA transition and the transition times for different alkali metal counterions conform to neither the simple sequence related to naked ion size nor to hydrated diameter, but an apparently abnormal sequence of K＋ 〈 Rb＋ 〈 Cs＋ 〈 Na＋ 〈 Li＋. This abnormal sequence can be well understood in terms of an electrostatic model based on the effective cation diameters and the modified mean-spherical approximation （MMSA）. The present results provide valuable information for the design of DNA-based nanomaterials and nanodevices.

Light scattering investigations on mercury ion induced amalgamation of gold nanoparticles in aqueous medium

With the aids of SEM,XPS measurements,localized plasmon resonance light scattering(PRLS) spectrometry and light scattering imaging,investigations on the amalgamation process of both cetyltrimethylammonium bromide(CTAB) and citrate-coated gold nanoparticles(AuNPs) in the presence of Hg2+ showed that the Au-Hg amalgam process of gold nanoparticles is surface coating dependent in aqueous medium,and the scattering light color change of AuNPs under a dark-field microscope is blue-shifted from red-orange into yellow-orange or even yellow.The former one involves the reduction of Hg2+ to Hg0 species and adsorption of Hg0 on the surfaces of AuNPs,while the later one indicates the shape-evolution of AuNPs.

Effect of anions from calcium sources on the synthesis of nano-sized xonotlite fibers

The xonotlite fibers were synthesized via the hydrothermal synthesis method with CaO and SiO_2 as the raw materials and the molar ratio of Si/Ca of 1.0. Effect of anions from various calcium sources on the microstructure of the xonotlite fibers is studied in this paper. These obtained products were characterized by X-ray diffraction(XRD), transmission electron microscope(TEM) and scanning electron microscope(SEM) techniques to investigate their crystalline phase, crystal structure and morphology. The results indicate that anion from various calcium sources has little influence on the crystalline phases of xonotlite fibers but poses a great impact on their morphologies. Xonotlite fibers with single crystal characteristics and large aspect ratio of 50—100 were successfully fabricated from CaCl_2 as calcium material at 225 °C for 15 h. The existence of Cl-anion in the CaO-SiO_2-H_2O system significantly contributes to the formation of xonotlite crystal.