超快门宽增强型CCD相机

利用德国LaVision公司门宽达到皮秒量级的超快门宽增强型CCD相机PicoStar研究二氧化钛微粒聚集体的局域化行为。

采用德国LaVision公司独特的皮秒门宽增强型CCD相机对鼠抗体样本进行了增强器快门门宽尺度对基于寿命的福斯特共振能量转移(FRET)参数的估计的研究。

Research on laser-liquid interaction and its induced fluid flows, as well as microbubbles, is important in many applications, such as laser ophthalmic microsurgery, manufacturing and repairing of micro-electronic-mechanical devices, laser deposition of thin liquid film to a specific location in micro system, etc. This work was focused on the interaction mechanisms of a laser pulse with distilled/degassed water as well as the characteristics of the microbubbles. Microbubbles and optohydrodynamic flows induced by a Nd:YAG pulse laser (New Wave Research) were studied. A recently improved PIV and PDA system were used to analyze the bubble dynamics and fluid flow quantitatively. Two CCD cameras were used to capture the images of microbubbles and visualize the laser induced Optohydrodynamic flows. The experimental results show that a bright fluid beam (density flow) with duration less than 127μs is produced by a focused laser pulse while an explosive cavitation just around the focus point is also occurred. Immediately following the fluid beam and the explosive cavitation, two new fluid regions which may be formed with the superheated dense fluid were found. One of them is just under the fluid beam due to the optical pressure while the other one is around the explosion area due to the force caused by the explosive cavitation. As shown in Figure 1, Single and multi microbubbles were generated immediately after the cavitation explosion when the nucleation conditions were satisfied. In addition, the characteristics, such as bubble velocities and diameters, were measured by a recently improved phase-Doppler anemometry (PDA). These results will help to have a better understanding of the mechanisms of laser-induced optohydrodynamic flows and bubbles related phenomena, which is crucial to numerical modeling.

Nitric oxide laser-induced-fluorescence (NO-LIF) 2-D imaging measurements using a new multi-spectral detection strategy are reported for high-pressure flames (1–60 bar). This work builds on previous research that identified interference LIF from O2 and CO2 in high-pressure flames and optimized the choice of excitation strategies as a function of application conditions. In this study, design rules are presented to optimize the LIF detection wavelengths for quantitative 2-D NO-LIF measurements over a wide range of pressures (1–60 bar) and temperatures. Simultaneous detection of LIF in multiple wavelength regions enables correction of the NO signal for interference from O2 and CO2 and allows simultaneous imaging of all three species. New experiments of wavelength-resolved 1-D LIF in slightly lean (/ = 0.9) and slightly rich (/ = 1.1) methane/air flames are used to evaluate the design rules and estimate the NO detection limits for a wide range of flame conditions. The quantitative 2-D measurements of NO in the burnt gas are compared with model calculations (using GRI-Mech 3.0) versus pressure for slightly lean and slightly rich flames. The discussions and demonstrations reported in this study provide a practical guideline for application of instantaneous 1-D or 2-D NO-LIF imaging strategies in high-pressure combustion systems.  2006 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

This paper describes the development of an experimental technique that combines simultaneous planar laser-induced fluorescence (PLIF) and infrared (IR) thermography imaging, and its application to the measurement of unsteady and conjugate heat-transfer in harmonically forced, thin liquid-film flows falling under the action of gravity over an inclined electrically heated-foil substrate. Quantitative, spatiotemporally resolved and simultaneously conducted measurements are reported of the film thickness, film free-surface temperature, solid–liquid substrate interface temperature, and local/instantaneous heat flux exchanged with the heated substrate. Based on this information, local and instantaneous heat-transfer coefficients (HTCs) are recovered. Results concerning the local and instantaneous HTC and how this is correlated with the local and instantaneous film thickness suggest considerable heat-transfer enhancement relative to steady-flow predictions in the thinner film regions. This behaviour is attributed to a number of unsteady/mixing transport processes within the wavy films that are not captured by laminar, steady-flow analysis. The Nusselt number Nu increases with the Reynolds number Re; at low Re values the mean Nu number corresponds to 2.5, in agreement with the steady-flow theory, while at higher Re, both the Nu number and the HTC exhibit significantly enhanced values. Evidence that the HTC becomes decoupled from the film thickness for the upper range of observed film thicknesses is also presented. Finally, smaller film thickness fluctuation intensities were associated with higher HTC fluctuation intensities, while the amplitude of the wall temperature fluctuations was almost proportional to the amplitude of the HTC fluctuations.

The ignition characteristics of a premixed bluff-body burner under lean conditions were investigated experimentally and numerically with a physical model focusing on ignition probability. Visualisation of the flame with a 5 kHz OH* chemiluminescence camera confirmed that successful ignitions were those associated with the movement of the kernel upstream, consistent with previous work on non-premixed systems. Performing many separate ignition trials at the same spark position and flow conditions resulted in a quantification of the ignition probability Pign, which was found to decrease with increasing distance downstream of the bluff body and a decrease in equivalence ratio. Flows corresponding to flames close to the blow-off limit could not be ignited, although such flames were stable if reached from a richer already ignited condition. A detailed comparison with the local Karlovitz number and the mean velocity showed that regions of high Pign are associated with low Ka and negative bulk velocity (i.e. towards the bluff body), although a direct correlation was not possible. A modelling effort that takes convection and localised flame quenching into account by tracking stochastic virtual flame particles, previously validated for non-premixed and spray ignition, was used to estimate the ignition probability. The applicability of this approach to premixed flows was first evaluated by investigating the model’s flame propagation mechanism in a uniform turbulence field, which showed that the model reproduces the bending behaviour of the ST-versus-u curve. Then ignition simulations of the bluff-body burner were carried out. The ignition probability map was computed and it was found that the model reproduces all main trends found in the experimental study.

A high level of fluorescence background signal rejection was achieved for solid and powder samples by using a combination of simple low-resolution spectrograph and ultrafast gated charge coupled device ~CCD! camera. The unique timing characteristics of the CCD camera match exceptionally well to characteristics of a Ti:sapphire oscillator allowing fast gated light detection at a repetition rate of up to 110 MHz, making this approach superior in terms of the duty cycle in comparison with other time-resolved Raman techniques. The achieved temporal resolution was about 150 ps under 785 nm Ti: sapphire laser excitation. At an average excitation power up to 300 mW there was no noticeable sample damage observed. Hence, the demonstrated approach extends the capabilities of Raman spectroscopy regarding the investigation of samples with a short fluorescence lifetime. The combination of a spectrometer and a gated CCD camera allows simultaneous study of spectral and temporal characteristics of emitted light. This capability opens an exciting possibility to build a universal instrument for solving multitask problems in applied laser spectroscopy

Electron heating, mechanisms of plasma generation, and electron dynamics in dif- ferent types of capacitively coupled radio frequency (CCRF) discharges relevant for industrial applications are investigated by a combination of di®erent experimen- tal diagnostics, simulations and models. Geometrically symmetric and asymmetric single frequency discharges operated at low pressures, geometrically symmetric dual frequency discharges operated at two substantially di®erent frequencies and two sim- ilar frequencies (fundamental and second harmonic with variable phase shift between the driving voltages) as well as hybrid capacitively/inductively coupled (CCP-ICP) RF discharges are studied. Electron heating is found to be strongly a®ected by phenomena characteristic for a certain discharge type, that do not occur in another. At low pressures the generation of highly energetic electron beams by the expand- ing sheath is observed. Such beams propagate through the entire plasma bulk and are re°ected at the opposing plasma boundaries, if the electron mean free path is long enough. An analytical model demonstrates that these beams lead to an en- hanced high energy tail of the electron energy distribution function and are, there- fore, closely related to stochastic heating

采用LaVision公司独有的，快门宽度最小可达50皮秒的增强型CCD相机，通过化疗可咯和多模光学成像方法对光子激发诱导线粒体损伤机理进行了研究。

Amphiphysin 1, an endocytic adaptor concentrated at synapses that couples clathrin-mediated endocytosis to dynamin-dependent fission,wasalsoshownto have a regulatory role in actindynamics. Here, we report that amphiphysin 1 interacts with N-WASP and stimulates N-WASP- and Arp2/3-dependent actin polymerization. Both the Src homology 3 and the N-BAR domains are requiredforthisstimulation.Acidicliposome-triggered,N-WASPdependent actin polymerization is strongly impaired in brain cytosol of amphiphysin 1 knock-out mice. FRET-FLIM analysis of Sertoli cells, where endogenously expressed amphiphysin 1 colocalizes with N-WASP in peripheral ruffles, confirmed the association between the two proteins in vivo. This association undergoes regulation and is enhanced by stimulating phosphatidylserine receptors on the cell surface with phosphatidylserine- containing liposomes that trigger ruffle formation. These results indicate that actin regulation is a key function of amphiphysin 1 and that such function cooperates with the endocytic adaptor role and membrane shaping/curvature sensing properties of the protein during the endocytic reaction.

An imaging fibre bundle is demonstrated for spatially-multiplexed probe beam delivery in OCT, with the aim of eliminating the mechanical scanning currently required at the probe tip in endoscopic systems. Each fibre in the bundle addresses a Fizeau interferometer formed between the bundle end and the sample, allowing acquisition of information across a plane with a single measurement. Depth scanning components are now contained within a processing interferometer external to the completely passive endoscope probe. The technique has been evaluated in our laboratory for non-biological samples. Images acquired using the bundle-based system are presented. The potential of the system is assessed, with reference to SNR performance and acquisition speed.

Fluorescence Spectroscopy in disease detection ?? Interaction of light with biological systems (molecules, cells, tissue). • Origin of fluorescence in biological systems ?? Instrumentation and Analytical Methods • Complete description of fluorescence emission ?? Interpret results. • Understanding of the physical-biological basis of the interaction.