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乳酸左氧氟沙星的紫外光谱性质与应用 总被引:3,自引:0,他引:3
在不同pH(1.89-11.58)的Britton-Robinson(B-R)缓冲溶液中,乳酸左氧氟沙星的紫外光谱性质,并对其吸收光谱的移动进行了详细的探讨。提出pH=2.87为分光光度法测定乳酸左氧氟沙星的最佳酸度,在最大吸收波长292nm处,测得其表观摩尔吸光系数为3.4×104L·mol-1·cm-1。乳酸左氧氟沙星的线性范围为1.0-23.0mg·L-1,检出限为0.565mg·L-1。该法成功用于药物制剂中乳酸左氧氟沙星含量的测定,结果满意。 相似文献
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Fluidics is one of the most historic subjects that are well-established over centuries on the macroscopic scale.In recent years,fluid detection using a number of micro/nano scale devices has been achieved.However,the interaction of microfluid and solid devices on micro/nano-meter scale still lacks in-depth research.We demonstrate a practical nanomechanical detector for microfluidics via a string resonator with high Q-factor,suspended over a hole.This device is placed under a jet nozzle with several microns of diameter,and the interaction between the micro-gas flow and the resonator is observed by monitoring the variation of the fundamental frequency and the quality factor.Moreover,we manage to measure the fluctuations of the micro-gas flow on the nanomechanical resonator by means of stochastic resonance.This work manifests a potential platform for detecting dynamical fluid behaviors at microscopic scale for novel fluid physics. 相似文献
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We realize a coherent transfer of mechanical excitation in a finely controlled artificial nanomechanical lattice.We also realize strong dynamic coupling between adjacent high-Q mechanical resonators,via modulated dielectric force at the frequency difference between them.An excitation transfer across a lattice consisting of 7 nanobeams is observed by applying a design sequence of switching for couplings,with the final effective population reaching 0.94.This work not only demonstrates the ability to fully control an artificial lattice but also provides an efficient platform for studying complicated dynamics in one-dimensional systems. 相似文献
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金刚石氮-空位色心结构因在量子精密测量领域的高灵敏度优势而备受关注.本文引入耦合声子场对氮-空位色心原子自旋进行共振调控,以提高氮-空位色心的自旋跃迁效率.首先,基于波函数和晶格的点阵位移矢量关系,分析了声子与晶格能量交互作用,研究了基于声子共振调控的氮-空位色心的自旋跃迁机理,建立了基于应变诱导的能量转移声子-自旋交互耦合激发模型.其次,基于氮-空位色心晶格振动理论,引入满足布洛赫定理的系数矩阵,建立了不同轴向氮-空位色心第一布里渊区特征区域的声子谱模型.同时,基于德拜模型,考虑热膨胀效应,解析该声子共振系统的声子热平衡性质,并对其比热模型进行研究.最后,基于分子动力学仿真软件CASTEP和密度泛函理论进行第一性原理研究,构建了声子模式下不同轴向氮-空位色心的结构优化模型,并分析了其结构特性、声子特性和热力学特性.研究结果表明,系统声子模式的演化依赖于氮-空位的占位,声子模式强化伴随着热力学熵的降低.含氮-空位色心金刚石的共价键较纯净无缺陷金刚石更弱,热力学性质更不稳定.含氮-空位色心金刚石的声子主共振频段处于THz量级,次共振频率约为[800,1200]MHz.根据次共振频段设计叉指宽度为1.5μm的声表面波共振机构,其中心频率约为930 MHz.在该声子共振调控参数条件下,声子共振调控方法可有效增大氮-空位色心的自旋跃迁概率,实现氮-空位色心原子自旋操控效率的提高. 相似文献
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Chiral State Conversion in a Levitated Micromechanical Oscillator with In Situ Control of Parameter Loops 下载免费PDF全文
Physical systems with gain and loss can be described by a non-Hermitian Hamiltonian, which is degenerated at the exceptional points(EPs).Many new and unexpected features have been explored in the non-Hermitian systems with a great deal of recent interest.One of the most fascinating features is that chiral state conversion appears when one EP is encircled dynamically.Here, we propose an easy-controllable levitated microparticle system that carries a pair of EPs and realize slow evolution of the H... 相似文献
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