离子阱中过渡金属Ti~ ,Co~ 与O_2的化学反应

利用激光溅射的方法产生并在射频离子阱中囚禁了Ti＋，Co＋离子，利用离子阱的质量选择存储和离子存储时间长等特点，开展了Ti＋，Co＋与O2的化学反应研究，得到了反应物的速率常数和反应产物分支比。结果表明，Co＋比Ti＋具有更大的化学活性，并且其二级产物（CoO2＋）具有更大的解离速率，因而更具有催化特性。     

Superfluid Rotation Sensor with Helical Laser Trap

The macroscopic quantum states of the dilute bosonic ensemble in helical laser trap at the temperatures about 10^?6 K are considered in the framework of the Gross-Pitaevskii equation. The helical interference pattern is composed of the two counter propagating Laguerre-Gaussian optical vortices with opposite orbital angular momenta ?? and this pattern is driven in rotation via angular Doppler effect. Macroscopic observables including linear momentum and angular momentum of the atomic cloud are evaluated explicitly. It is shown that rotation of reference frame is transformed into translational motion of the twisted matter wave. The speed of translation equals the group velocity of twisted wavetrain V _z =Ω?/k and alternates with a sign of the frame angular velocity Ω and helical pattern handedness ?. We address detection of this effect using currently accessible laboratory equipment with emphasis on the difference between quantum and classical fluids.     

矩形离子阱质谱仪软件系统的设计

摘要:针对矩形离子阱质谱仪时序控制复杂,控制软件的设计与开发困难的问题.提出一种控制离子阱质谱仪的时序可配置模型和模块化的软件系统结构,并开发出软件系统.在GC-EI-Trap联用仪和LC-ESI-Trap联用仪上应用测试表明软件系统具有实用性和可扩展性.     

A Microfluidic Ion Sensor Array

A balanced concentration of ions is essential for biological processes to occur. For example, [H⁺] gradients power adenosine triphosphate synthesis, dynamic changes in [K⁺] and [Na⁺] create action potentials in neuronal communication, and [Cl^?] contributes to maintaining appropriate cell membrane voltage. Sensing ionic concentration is thus important for monitoring and regulating many biological processes. This work demonstrates an ion‐selective microelectrode array that simultaneously and independently senses [K⁺], [Na⁺], and [Cl^?] in electrolyte solutions. To obtain ion specificity, the required ion‐selective membranes are patterned using microfluidics. As a proof of concept, the change in ionic concentration is monitored during cell proliferation in a cell culture medium. This microelectrode array can easily be integrated in lab‐on‐a‐chip approaches to physiology and biological research and applications.     

In-flight Capture of an Ion Beam in a Paul Trap

Abstract

A system for collecting 60 keV ion beams was set up at the ISOLDE-3 radionuclide mass-separator facility at CERN. Electric field retardation was used to bring the ions to 20 eV for injection into a Paul trap. Tests were made with ¹³²Xe⁺ and ⁷⁹Br^? ions. A trap potential well depth of about 30 V could be created. At this well depth a collection efficiency of about 0·2% was obtained for a xenon beam of emittance about 2π mm-mrad and energy spread estimated to be of a few electronvolts. The efficiency for bromine ions was less, but still appreciable. The efficiencies achieved indicate that a sizeable fraction of the ions arriving at the correct rf window for acceptance by the trap were being collected. To the limit of the apparatus, the efficiency was increasing in proportion to the third power of the rf amplitude applied to the trap, indicating that it was proportional to the phase space volume of the trap. These results are now being used to design a larger Paul trap collection system for installation at the ISOLDE-BOOSTER facility. By including a pre-bunching system to fit an incoming dc beam to the rf acceptance, it is expected that almost complete collection of weak mass-separated high-velocity beams can be achieved.     

Photon Correlation Measurement of Ion Oscillation Frequencies in a Combined Trap

Abstract

We present experimental verification of the oscillation frequencies of magnesium ions in a combined trap for a wide range of a.c. voltages and magnetic fields. We employ a new technique to measure these trap resonances using the distribution of time intervals between consecutively detected fluorescence photons.     

离子在矩形波四极场中的运动与四极场离子阱质谱的数字化操作

矩形波驱动的四极场同样可用于对离子进行质量分析和存储。本文推导了离子在矩形波四极场中的运动规律,并以常用于正弦波四极场的马绍方程参量a,q来表出离子的稳定性。运用赝势阱概念探讨了离子在这种四极场中的本征振动,推导了本征振动频率的近似公式。在理论研究的基础上,提出了数字化离子阱质谱的概念,并运用离子光学模拟,研究了实际离子阱几何结构下的共振出射以及数字化质量扫描的可行性。     

Improvements in LC/Electrospray Ion Trap Mass Spectrometry Performance Using an Off-Axis Nebulizer

Charged residues from the electrospray process have been hypothesized to limit the sensitivity and dynamic range of an ion trap mass spectrometry operation. Incorporation of an off-axis nebulizer (positioned 90-95° from the sampling orifice) was found to drastically reduce the detrimental effects caused by the charged particles or droplets compared to typical on-axis nebulization configurations (spraying 10-20° from sampling orifices). The off-axis nebulizer reduced total ion currents that enter the ion trap (through the reduction of charged residues) by a factor of 5-7 while resulting in an increase of analyte [M + H](+) signal by a factor of 6 compared to an on-axis sprayer at flow rates of 20 μL/min. At higher flow rates (e.g., 800 μL/min) these enhancements are more evident. At flows greater than 200 μL/min, off-axis nebulization reduced total ion current that enters the ion trap by a factor of 30 and resulted in a factor of more than 20 increase in [M + H](+) signal relative to on-axis nebulization. Incorporation of the off-axis nebulizer improved the detection limit and precision for determination of dihydroxyvitamin D(3) in plasma compared to on-axis nebulization. The LC/MS/MS detection limits obtained for the off-axis nebulizer on the ion trap was within a factor of 2 from the detection limit determined by the triple quadrupole. The relative standard deviation of the dihydroxyvitamin D(3) determination was less than 8% for both off-axis ion trap and triple-quadrupole determinations.     

A Distributed Optical Fiber Chemical Sensor System

ＩｎｔｒｏｄｕｃｔｉｏｎＯｐｔｉｃａｌｆｉｂｅｒｔｅｃｈｎｏｌｏｇｙｐｒｅｓｅｎｔｓｍａｎｙａｔｒａｃｔｉｖｅｐｏｓｉｂｉｌｉｔｉｅｓｉｎｔｈｅａｒｅａｏｆｃｈｅｍｉｃａｌｓｅｎｓｉｎｇ．Ｔｈｅｕｓｅｏｆｏｐｔｉｃａｌｆｉｂｅｒａｌｏｗｓｓｉｇｎａｌ...     

Design and Construction of a Helical Resonator for Delivering Radio Frequency to an Ion Trap

Supplying high voltage radio frequency (RF) is a critical part of ion trapping system due to impedance mismatching between RF source and the ion trap. A helical resonator has been constructed in order to deliver narrow bandwidth and high voltage RF to the ion trap for stable confinement of ions. The performances of the helical resonator have been studied for different capacitive load of the ion trap. Both the resonant frequency and quality factor of the resonator show strong dependence on external capacitive loads.     

A Pillar-Shaped Antifuse-Based Silicon Chemical Sensor and Actuator

We designed a silicon-processing compatible, simple, and cheap device operating at a power down to sub-muW. It has a pillar-shaped structure with a nanoscopic (10-100 nm in size) conductive link (the so-called antifuse) created between two electrodes separated by a SiO ₂ layer. The device exhibits a diode-like behavior due to the depletion effects in the mono-silicon pillar. The device is capable of maintaining a microscopic hot-surface area of several hundreds degrees centigrade. The size of the hot area and its temperature can be manipulated by the sign of the applied bias. Two different heat-generation mechanisms (i.e., dissipation at a resistor and a non-radiative recombination of carriers) are proposed and modelled. Such a device can be used as a heat source, as a light source, and as a sensitive detector of light and heat. In this paper, we describe thermo-electrical properties of the fabricated devices and demonstrate their feasibility to perform as gas-, adsorption-, desorption sensors, and as units for activating chemisorption/decomposition of gaseous precursors, i.e., micro-reactors     

有机高分子磁性材料研究进展

有机高分子磁性材料作为一种新型的功能材料,在超高频装置、高密度存贮材料、吸波材料和微电子工业等需要轻质磁性材料的领域具有很好的应用前景。室温稳定且具有实用价值的有机高分子磁性材料一直是该领域研究的热点。文中概述了纯有机类,大π键体系类,电荷转移复合物类和含金属原子复合物类等有机高分子磁性材料的最新研究进展,并介绍了各类有机高分子磁性材料的磁性能特点。     

Conditions of Ion Motion Confinement in an Electrostatic Trap with Separation of Variables in Parabolic Coordinates

Refined conditions for the confinement of ion motion in the trapping field admitting separation of variables in parabolic coordinates are formulated. The simplicity of equations allows some results to be obtained in an elementary form, which makes it possible to consider the issue of particle confinement in these systems in detail.     

Miniaturized Sensor for Microbial Pathogens DNA and Chemical Toxins

A miniaturized, inexpensive and battery operated ultra-sensitive nanomaterial-based fluorescence resonance energy transfer (NSET) probe has been developed and evaluated for screening microbial pathogens DNA and chemical toxins at high sensitivity and selectivity. This paper illustrates application of the NSET portable device to detect microbial pathogens, e.g., Campylobacter, C. perfringens, and S. aureus DNA based on quenching of the NSET signal by gold nanoparticles to detect single base-mismatch DNA with high sensitivity (600 fM). Presence of the fluorescence signal indicates that the target DNA has been detected. We also report that the NSET probe is capable of screening chemical toxins like mercury from contaminated water with excellent sensitivity (2 parts-per-trillion) and selectivity for over competing analytes.     

一种光纤化学二氧化碳传感器的研制

研究开发了一种基于指示剂的二氧化碳光纤化学传感器,采用具有高气体可透过性和低折射率的无定型聚四氟乙烯(Teflon AF)材料作为液芯波导管,高灵敏度微型CCD分光光度计作为检测器,溴百里酚蓝(BTB,bromothymol blue)和Na2CO3为指示剂缓冲溶液。在0～194 ppm的CO2浓度范围内,传感器最佳精度为±1.21ppm,响应时间(99％)约为2 min。传感器具有体积小,能耗低等特点,适于现场长期自动监测。     

空间光学遥感器反射镜离子束加工过程的热效应

针对空间光学遥感器反射镜离子束加工过程中,离子束瞬态大热流密度造成加工过程镜体温度急剧上升引起的热应力问题,利用UG8.5软件flow thermal高级仿真模块对反射镜组件的温度场进行瞬态仿真,预示加工过程的温度场,将温度场映射至结构有限元模型,利用NX NASTRAN计算出反射镜组件的热应力分布。根据反射镜组件的加工环境和结构特点,采取导热措施将加工过程热量疏导至大热容工装板。结果表明,采取热控措施后反射镜组件加工过程最高温度降低15%,对应的最大热应力降低27%,有效降低了反射镜组件的热应力;通过ZYGO干涉仪检测加工完成后的反射镜面型,面型精度优于λ/50,为空间光学反射镜离子束加工提供了有效的保障。     

离子化学热处理的若干理论和技术问题

离子化学热处理具有节能、高效、优质、无污染等优点,近年来发展很快,但要广泛应用,尚须解决一些理论和技术问题,作者根据多年的实际经验在本文中对这些问题进行了探讨。     

食品接触材料中邻苯二甲酸酯的LTQ-Orbitrap组合式高分辨质谱快速筛查和确证

建立了食品接触材料中邻苯二甲酸酯快速筛查确证的高效液相色谱-高分辨质谱法(HPLC-LTQ-Orbi-trap/MS)。实验中采用加速溶剂萃取(ASE)法为样品前处理手段,优化了萃取溶剂、萃取温度、静态萃取时间等实验参数,提高了食品接触材料中邻苯二甲酸酯的提取效率。采用高分辨质谱有效地去除了基体干扰,通过静电场轨道阱全扫描得到的精确相对分子质量进行了化合物的定量,用离子阱的二级质谱图对未知化合物进行了进一步确证。结果表明:邻苯二甲酸酯的检测限为1 ng/mL;该方法的加标回收率为89.8%～101.3%,相对标准偏差均小于8.0%;所建立的方法简单,灵敏度高,适用于食品接触材料中邻苯二甲酸酯类增塑剂的筛查和检测。     

An Ultrasensitive Silicon Photonic Ion Sensor Enabled by 2D Plasmonic Molybdenum Oxide

Silicon photonics has demonstrated great potential in ultrasensitive biochemical sensing. However, it is challenging for such sensors to detect small ions which are also of great importance in many biochemical processes. A silicon photonic ion sensor enabled by an ionic dopant–driven plasmonic material is introduced here. The sensor consists of a microring resonator (MRR) coupled with a 2D restacked layer of near‐infrared plasmonic molybdenum oxide. When the 2D plasmonic layer interacts with ions from the environment, a strong change in the refractive index results in a shift in the MRR resonance wavelength and simultaneously the alteration of plasmonic absorption leads to the modulation of MRR transmission power, hence generating dual sensing outputs which is unique to other optical ion sensors. Proof‐of‐concept via a pH sensing model is demonstrated, showing up to 7 orders improvement in sensitivity per unit area across the range from 1 to 13 compared to those of other optical pH sensors. This platform offers the unique potential for ultrasensitive and robust measurement of changes in ionic environment, generating new modalities for on‐chip chemical sensors in the micro/nanoscale.