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病原菌污染给人类的健康带来极大的安全隐患,对病原菌快速、准确和灵敏的检测是减少污染的重要手段。传统检测病原菌的方法存在耗时长和操作繁琐等缺点。荧光纳米材料具有荧光强度高、稳定性好以及良好的生物相容性等优势,为应用其构造传感器用于病原菌检测提供了新的研究途径。本文对近年来常见荧光纳米材料,包括半导体量子点、金属纳米簇、碳纳米材料、上转换纳米粒子和荧光硅纳米颗粒,在病原菌检测方面的应用进行了概述,着重将不同类别荧光纳米材料的光学性质和检测机理进行了分析和比较。纳米材料的生物修饰是实现病原菌特异性识别的重要环节,本文对抗体、适配体、噬菌体和抗生素等病原菌识别方式的特点及其与纳米材料的连接方式进行了介绍。最后对不同荧光纳米材料在检测病原菌中具有的优势和局限性进行了总结,并对其在未来的应用与研究重点进行了展望。 相似文献
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Using the technology of pressure jump, variations of temperature associated with pressure from 2.4 GPa to 4.6 GPa are measured for lead. The Grfuneisen parameter is calculated from the thermodynamic relation γ =(Ks/T)(aT/aP)s, in which substitution of △T/△P for aT/aP at median pressure is strictly justified. The correction of temperature change is carried out by analysing the experimental data, which makes the process more approaching to an adiabatic condition. The calculated values of △T/ △ P and γ gradually decrease with the increasing pressure. The decrease trend is consistent with the previous work. The γ values in the range of 2-3 GPa are averagely higher than the results of Ramakrishnan et al., indicating the effect of temperature correction. The improved method is promising for measurements of Grfineisen parameter to higher pressure range. 相似文献
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在室温下对干燥的一年生矮种长春花种子进行了静高压氮气处理,压力分别为10、20、30 MPa,保压4 h。将各处理组与未经高压处理的对照组种子同时在相同的自然条件下进行播种培育。详细观察对比了各组植株的花形等性状,用高效液相色谱检测了生长旺盛期植株中长春碱和长春新碱的含量,另外还观察了剪枝后再生植株的生长性状。结果表明:种子经高压处理的各组长春花植株中的长春碱含量都有显著增加;长春新碱含量也有提高趋势。这种变化与花形改变和再生植株患病率的分布有一定程度的对应关系。初步认为植株体内长春碱含量的提高可能与高压导致的愈伤组织有关。 相似文献
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The melt's solidification behavior of elemental selenium is investigated by a series of experiments including rapid compressing to 2.8 and 3.5 GPa within 20ms respectively, slow compressing to 2.8 GPa for 20 min and natural cooling at ambient pressure. Based on the x-ray diffraction, scanning electron microscope and transmission electron microscope results of the recovered samples, it is clearly shown that homogenous nanostructures are formed only by the rapid compression processes, and that the average crystal sizes are about 18.7 and 19.0 nm in the samples recovered from 2.8 and 3.5 GPa, respectively. The relative density of the nanocrystalline bulk reaches 98.17% of the theoretical value. It is suggested that rapid compression could induce pervasive nucleation and restrain grain growth during the solidification, which is related to fast supercooling, higher viscosity of the melt and lower diffusivity of atoms under high pressure. 相似文献
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Using a pseudopotential plane-waves method,we calculate the phonon dispersion curves,thermodynamic properties,and hardness values of α-CdP_2 and β-CdP_2 under high pressure.From the studies of the phonon property and enthalpy difference curves,we discuss a phase transform from β-CdP_2 to a-CdP_2 in a pressure range between 20 GPa and 25 GPa.Then,the thermodynamic properties,Debye temperatures,and heat capacities are investigated at high pressures.What is more,we employ a semiempirical method to evaluate the pressure effects on the hardness for these two crystals.The results show that the hardness values of both α-CdP_2 and β-CdP_2 increase as pressure is increased.The influence mechanism of the pressure effect on the hardness of CdP_2 is also briefly discussed. 相似文献
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采用高压技术实现了500 MPa下聚左旋乳酸(PLLA)在稀薄二甲苯溶液中的单晶生长,采用透射电子显微镜、拉曼光谱和红外光谱对样品的结晶形态和结构进行了表征,考察了高压对聚左旋乳酸单晶生长行为的影响。结果表明,在相同的结晶温度和时间下,高压结晶PLLA的单晶仍为α-型晶体,但单晶尺寸明显大于常压样品;高压环境下PLLA分子链在晶核两端的生长扩散速率不同,容易形成非对称的菱晶形态;高压影响PLLA晶体中分子链的构象分布;在单晶生长期,高压诱导有利于PLLA晶体成核,但不利于单晶生长。 相似文献