其他检测

采用全新二元配置的Waters ACQUITY UPLC H-Class PLUS二元系统是对现有ACQUITY UPLC H-Class PLUS四元系统的补充。 该系统具有二元溶剂管理功能，拥有与四元系统相同的低扩散性和稳定性，采用0.005 in/0.127 mm管路，最高可支持15,000 psi的工 作背压。系统由二元溶剂管理器、流通针式样品管理器以及带主动预加热功能的色谱柱管理选件组成，用户可选配单色谱柱柱温箱或 最多可加热/冷却6根色谱柱的色谱柱管理器。

什么是阈值？ 阈值处理是一种在图像处理中使用的图像分割方法，用于从背景中辨别对象的边界的方法。 当阈值缺失或配置不当时，大多数成像颗粒分析仪经常对半透明粒子（例如蛋白质聚集体）进行错误表征或甚至未检测到。 大多数成像粒子分析仪提供的暗像素阈值处理，当它比成像背景更亮时，无法识别颗粒物质。 利用暗阈值和亮阈值可以检测和识别表现出不透明度范围的颗粒（透明不透明），并提高颗粒分析仪检测，成像和分析半透明颗粒的能力。

在LAMBDA 950/1050中安装马达驱动动变角的通用反射附件和马达驱动的偏振器附件，可轻松实现增强型镜面反射膜性能的自动验证。由于增强型镜面反射膜的厚度极薄且柔软，因此，要想在常规分光光度计系统和附件中专为硬质滤光片和玻璃设计的垂直样品架上妥当地固定超薄增强型镜面反射膜的难度极大。通用反射附件的独特设计（即，无样品架设计，样品只需平放在顶板的测样口上）能够确保精确地测量增强型镜面反射膜的镜面反射率。

随着离子色谱日益广泛的应用，许多样品已经无法用传统的方法采用采样、稀释、过滤后直接进样的模式来进行离子色谱的分析。对于大量复杂基体的样品，离子色谱可以采用合适的方法，通过预处理后再用离子色谱法进行分析，这样一方面可以解决样品复杂基体对离子色谱柱的沾污，另一方面也可以大大提高以复杂基体样品测定结果和准确性、提高分析方法的灵敏度。

Biotage是最早开发出商品化的快速制备色谱仪的公司。市场占有率最高。 Biotage最新推出智能化的快速制备色谱, 具有优秀的分离效果，最高的纯度和收率。

Injection processing of composite materials most often includes infiltration of a thermoset resin into a multi-scale porous fabric. Controlling the fluid flow within the multiscale fabric is essential for the quality of the final composite material, since the transport of fluid between regions with different scales plays an important role in phenomena such as void formation and filtration of particle doped resins. In this work, the transient flow behaviour in dual scale porous media is investigated with Micro Particle Image Velocimetry in order to enhance the knowledge and control of the processing of multi-scale composites so that their quality can be improved. Experiments show that the fluid transport between the two scales can be controlled by the injection velocity. Validation of the measured velocity fields furthermore shows excellent agreement with theory.

Two novel techniques based on Laser-Induced Fluorescence (LIF) were applied to measure gas-phase temperature distributions in boundary layers close to wall surfaces. Single line toluene-LIF thermometry was used to image temperature in a nitrogen gas flow above a heated wall. The nitrogen gas flow was doped with evaporated toluene. When excited at 266 nm, the toluene LIF-signal shows an exponential dependence on temperature. This behavior was used to calculate absolute temperatures from LIF images after calibration at known conditions. The second technique, multi-line NO-LIF thermometry was applied to image temperature in the quenching boundary layer close to a metal wall located on a flat flame burner. A small amount of nitric oxide was mixed into the air/methane mixture. NO molecules were excited in the A-X (0,0)-band at 225 nm. NO-LIF excitation spectra were acquired by tuning the excimer laser wavelength and recording the NO LIF-signal with an ICCD camera. Absolute temperatures were calculated for every pixel by fitting simulated excitation spectra to the experimental data. Temperature distributions close to the wall surface were measured at two different flow-rate conditions. A high nominal spatial resolution of 0.016 mm/pixel in direction perpendicular to the wall was reached. Wall surface temperatures were recorded simultaneously by embedded thermocouples and compared with gas-phase temperature near the wall surface.

采用配备全能型测量附件包的 Cary 5000 分光光度计测量了两种样品的折射率。其中一个样品为纳米复合涂层：石英基底（可见光范围内透明）上的 Zr-Si-B-(N) 薄膜。第二个样品为单晶硅基底（可见光范围内不透明）上的铌酸锂 LiNbO3 层状结构。计算出了两个样品的折射率，准确度为 ±0.01。根据所测定的折射率，计算了两个样品的薄膜厚度。

标准曲线拟合好，主灵敏线 R=0.99997，次灵敏线R= 0.9998， RSD＜1%。标准溶液重测回收率——QC3为 101.5%，QC4为99.79%。每个样品重复测定3次的结果非常相近。说明仪器的稳定性好，测定结果准确、可靠，完全适合该类样品的测试。主灵敏线与次灵敏线的测试结果基本相近。

文章作者建立了一套完整的生物气溶胶研究平台,从生物气溶胶的发生到特性研究,再到生物气溶胶的体内注入研究,数据详尽,内容翔实,研究领域处于世界前沿. 文中具体介绍了气溶胶发生器,气溶胶粒径测定仪,生物撞击采样器等仪器的使用方法,数据分析等

A numerical implementation of the advection equation is proposed to increase the temporal resolution of PIV time series. The method is based on the principle that velocity fluctuations are transported passively, similar to Taylor’s hypothesis of frozen turbulence. In the present work, the advection model is extended to unsteady threedimensional flows. The main objective of the method is that of lowering the requirement on the PIV repetition rate from the Eulerian frequency toward the Lagrangian one.

C18AQ柱在Flash制备纯化样品中的一个典型应用是脱盐操作，即除去样品溶剂中的盐或缓冲液组分，以方便样品应用于后续研究中。在本案例中，某大极性化合物作为样品在C18AQ柱上进行了分离纯化，去除了粗品中所含的盐类杂质，且将样品从水相溶剂中转移至有机相体系中，从而方便了后续的旋蒸等操作，节省了溶剂及操作时间。

采用LaVision公司的充氦肥皂泡，可以获得大尺度，空气中中性飘浮均匀，大流量的示踪粒子集合。是测量大尺度3D3C层析PIV的理想示踪粒子源。测量尺度可以达到米的量级。

利用LaVisin公司提供的高速CMOS相机和高速图像增强器HS-IRO构成一套时间分辨PIV和PLIF联合测试系统，用于分析双稳态湍动旋流火焰中进动涡核（PVC）形成和火焰形状变化之间瞬态耦合过程。

采用LaVision公司的FlowMaster系统测量平面流动的速度场分布，同时用红外相机测量温度场。这对研究热传导机制非常有效。

采用两台LaVision公司的HighSpeedStar6 型高速相机，记录仿真蜂鸟扑翼机的振翅动作过程。

采用ImagerProX4M相机。长工作距离显微镜。测量一个粗糙的砂轮圆盘在液体池中旋转时所产生的流场。

LaVision公司的首席执行官Bernhard Wieneke是PIV领域的著名学者。在PIV不确定度的定量分析领域发表过多篇高水平，开拓性的文章。这是其中一篇。

采用LaVision公司最短帧间时间间隔可达115纳秒的跨帧相机，可以测量的速度上线可达十几公里/秒。本文的测试速度就达到了5倍音速。

在温度最高可达1000度的高温环境中进行三维非接触式形变应变测量。需要克服高温时被测对象的自发辐射干扰。解决喷涂标点油漆耐高温的难题。

提出了一种新颖的基于结构化光照明的方法，基于数字图像相关（DIC）原理实现用一台相机进行3维表明形貌，形变以及应变测量。

Two-dimensional velocity fields around a freely swimming freshwater black shark fish in longitudinal (XZ) plane and transverse (YZ) plane are measured using digital particle image velocimetry (DPIV). By transferring momentum to the fluid, fishes generate thrust. Thrust is generated not only by its caudal fin, but also using pectoral and anal fins, the contribution of which depends on the fish’s morphology and swimming movements. These fins also act as roll and pitch stabilizers for the swimming fish. In this paper, studies are performed on the flow induced by fins of freely swimming undulatory carangiform swimming fish (freshwater black shark, L = 26 cm) by an experimental hydrodynamic approach based on quantitative flow visualization technique. We used 2D PIV to visualize water flow pattern in the wake of the caudal, pectoral and anal fins of swimming fish at a speed of 0.5–1.5 times of body length per second. The kinematic analysis and pressure distribution of carangiform fish are presented here. The fish body and fin undulations create circular flow patterns (vortices) that travel along with the body waves and change the flow around its tail to increase the swimming efficiency. The wake of different fins of the swimming fish consists of two counterrotating vortices about the mean path of fish motion. These wakes resemble like reverse von Karman vortex street which is nothing but a thrust-producing wake. The velocity vectors around a C-start (a straight swimming fish bends into C-shape) maneuvering fish are also discussed in this paper. Studying flows around flapping fins will contribute to design of bioinspired propulsors for marine vehicles.

The entire process of atomization of the fuel in an internal combustion engine plays a very important role in determining the overall efficiency of these engines. A good atomization process could help the fuel to mix with the air properly leading to its efficient combustion, thereby reducing the emitted pollutants as well. The recent trend followed by the engineers focused on designing fuel injectors for more efficient atomization is to increase the atomization pressure while decreasing the nozzle orifice diameter. A consequence of this is the development of cavitation (formation of vapor cavities or bubbles in the liquid) inside the injector close to the nozzle. The main reason behind this is the sudden changes in the pressure inside the injector and these cavities or bubbles are usually formed where the pressure is relatively low. This work mainly focuses on studying the formation of cavitation and its effect on the velocity of the spray in the near nozzle region using asymmetrical transparent nozzle equipped with a needle lift sensor with nozzle diameter of 0.35 mm at 300 bar of injection pressure. The experiment consists in recording of several image-pairs, which are separated by about 300 ns, capturing the dynamics of the spray, a few millimeters from the nozzle in the direction of the flow. These image-pairs are then used to compute the velocity from the displacement of the liquid structures and ligaments by correlating the first image with the second. About 200 of such velocity graphs are then averaged to obtain a velocity map and is compared with the similar average velocity maps obtained at different times from the start of the injection. The angular spread of the spray from each of these images is calculated as well. The images showing cavitation in-side the injector are also recorded at these same instants of time so as to understand the effects of cavitation on the velocity and angular spread of the spray close to the nozzle.

This paper highlights the influence of contact line (pinning) forces on the mobility of dry bubbles in microchannels. Bubbles moving at velocities less than the dewetting velocity of liquid on the surface are essentially dry, meaning that there is no thin liquid film around the bubbles. For these “dry” bubbles, contact line forces and a possible capillary pressure gradient induced by pinning act on the bubbles and resist motion. Without sufficient driving force (e.g. external pressure) a dry bubble is brought to stagnation. For the first time, a bipartite theoretical model that estimates the required pressure difference across the length of stagnant bubbles with concave and convex back interfaces to overcome the contact line forces and stimulate motion is proposed. To validate our theory, the pressure required to move a single dry bubble in square microchannels exhibiting contact angle hysteresis has been measured. The working fluid was deionized water. The experiments have been conducted on coated glass channels with different surface hydrophilicities that resulted in concave and convex back interfaces for the bubbles. The experimental results were in agreement with the model’s predictions for square channels. The predictions of the concave and convex back models were within 19% and 27% of the experimental measurements, respectively.

We present the results of a laboratory experimental study of an internal wave field generated by harmonic, spatially periodic boundary forcing from above of a density stratification comprising a strongly stratified, thin upper layer sitting atop a weakly stratified, deep lower layer. In linear regimes, the energy flux associated with relatively high frequency internal waves excited in the upper layer is prevented from entering the lower layer by virtue of evanescent decay of the wave field. In the experiments, however, we find that the development of parametric subharmonic instability in the upper layer transfers energy from the forced primary wave into a pair of subharmonic daughter waves, each capable of penetrating the weakly stratified lower layer. We find that around 10% of the primary wave energy flux penetrates into the lower layer via this nonlinear wave-wave interaction for the regime we study.

Recent advances in composite manufacturing have occurred predominantly in the aerospace, marine, automotive and related industries. Whilst, formerly, naval vessels were constructed from steel, composites provide a significant weight reduction and increase in stealth properties whilst maintaining high strength properties. However composite sandwich materials have yet to be widely adopted in the construction of naval vessels despite their excellent strength to weight ratio and low radar return. One barrier to their wider use is our limited understanding of their performance when subject to air blast.

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.

A stereo-μ-PIV system for the measurement of all three components of the velocity vector in a measurement plane (2D-3C) in a closed microchannel has been developed and first test measurements have been performed on the three-dimensional laminar flow in a T-shaped micromixer. Stereo-μ-PIV measurements in closed microchannels require a calibration based on the self-calibration of the tracer particle images. In order to include the effects of different refractive indices of the water in the microchannel, the glass of the entrance window, and the surrounding air a three-media-model is included in the triangulation procedure of the self calibration. A preliminary test case shows that the stereo-μ-PIV results deviate less than 5% from theoretical values. First measurements in the mixing zone of a T-shaped micromixer show that three-dimensional flow in a microchannel can be resolved, however, the accuracy of the measurements needs to be improved.

The mass balance of orchard air-blast sprayers has historically been assessed using an array of samplers to capture airborne particles. However, these methods only provide an idea of flux with no other information which is pertinent to understand the movement of droplets and their potential to drift. While droplet analysis for agricultural sprayers has always been conducted in a laboratory setting with the use of laser devices, a new phase Doppler approach is being explored to assess droplet spectra, velocity, and flux in outdoor field conditions. Therefore it is the objective of this study to develop a methodology and the potential limitations for using a phase Doppler system while in a laboratory setting. Due to the expected variability of field conditions as well as the turbulence of orchard sprayers, a computational approach was sought to assess flux from a single scan of a conical spray plume's diameter. Using a constant scanning speed of 0.0079 m/s, a disc core (D1/DC33) hollow cone nozzle was examined at 310, 410, and 520 kPa pressure at five different heights (10, 20, 30, 40, and 50 cm). Computational flux was then compared to the actual flow rate, finding a
3.3% average error with a range of
16.9% and 4.7% illustrating a small underestimation of mass with the phase Doppler which was related to distance and droplet frequency. Further, comparisons were also assessed including pattern/symmetry, droplet spectra, velocity, and the overall number of samples. The proposed methodology indicates potential for the use of phase Doppler technology for in situ measurements of spray equipment using a conical-type spray nozzle, such as that of the orchard air-blast sprayer.

Crude Unit Column Overhead – Corrosion Water is usually injected in the overhead piping to: • Help quench and scrub the overhead vapors • Dilute acids formed • Prevent any salts or acids from forming in the system