Fiber-optic infrared radiometer for accurate temperature measurements

A fiber-optic radiometer is developed for accurate noncontact temperature measurements. Of compact and novel design, it is based on replacing the usual chopper with a simple shutter. The radiometer operates in a spectral range of 5-20 microm and uses a silver-halide IR-transmitting optical fiber. The radiometer has a temperature resolution of 0.1 degrees C, a time response of 200 ms, and a spatial resolution of approximately 1 mm. Theory, simulation, radiometer design and construction, and examples of experimental measurements are shown. The novel radiometer can be used in diverse applications in science, medicine, and industry.     

The measurement of specimen surface temperature in high-speed tension and torsion tests

A radiometric technique has been developed capable of measuring specimen surface temperatures as low as 25°C with a time resolution of ∼1 μs. The application of this technique to SHPB tests at strain rates of the order of 1000/s in both tension and torsion is described. In the torsion test results are obtained both during uniform deformation, using a single element radiometer, and during localised deformation and the onset of fracture, using a 12-element radiometer. In the tension test the same 12-element radiometer was used to obtain the surface temperature distribution along each half of the broken specimen immediately after fracture. The proportion of work converted to heat, β, has been calculated using the temperature data from torsion tests and was found to vary with increasing plastic strain from approximately 0.2 to approaching 0.7.     

Elucidation of reaction mechanisms responsible for afterglow and reagent-ion formation in the low-temperature plasma probe ambient ionization source

The development of ambient desorption/ionization mass spectrometry has shown promising applicability for the direct analysis of complex samples in the open, ambient atmosphere. Although numerous plasma-based ambient desorption/ionization sources have been described in the literature, little research has been presented on experimentally validating or determining the desorption and ionization mechanisms that are responsible for their performance. In the present study, established spectrochemical and plasma physics diagnostics in combination with spatially resolved optical emission profiles were applied to reveal a set of reaction mechanisms responsible for afterglow and reagent-ion formation of the Low-Temperature Plasma (LTP) probe, which is a plasma-based ionization source used in the field of ambient mass spectrometry. Within the dielectric-barrier discharge of the LTP probe, He(2)(+) is the dominant positive ion when helium is used as the plasma supporting gas. This helium dimer ion (He(2)(+)) has two important roles: First, it serves to carry energy from the discharge into the afterglow region in the open atmosphere. Second, charge transfer between He(2)(+) and atmospheric nitrogen appears to be the primary mechanism in the sampling region for the formation of N(2)(+), which is an important reagent ion as well as the key reaction intermediate for the formation of other reagent ions, such as protonated water clusters, in plasma-based ambient ionization sources. In the afterglow region of the LTP, where the sample is usually placed, a strong mismatch in the rotational temperatures of N(2)(+) (B (2)Σ(u)(+)) and OH (A (2)Σ(+)) was found; the OH rotational temperature was statistically identical to the ambient gas temperature (~300 K) whereas the N(2)(+) temperature was found to rise to 550 K toward the tail of the afterglow region. This much higher N(2)(+) temperature is due to a charge-transfer reaction between He(2)(+) and N(2), which is known to produce rotationally hot N(2)(+) (B (2)Σ(u)(+)) ions. Furthermore, it was found that one origin of excited atomic helium in the afterglow region of the LTP is from dielectronic recombination of vibrationally excited He(2)(+) ions.     

Power voltage source synchronized with a spectrometer for real-timespectroscopic studies of pulsed discharges

The evolution of the species generated in a plasma may be characterized through real-time optical emission spectroscopy. Nevertheless, for experimental situations in which the light emission intensity is insufficient for acquisition times of several tens of milliseconds (typical resolution time of optical multichannel analyzers), some complementary instrumentation has to be incorporated. In this paper, we present the design of an experiment to study the spectroscopic evolution of a plasma during a switch-on of a dc discharge, and/or during its switch-off (afterglow). The solution consisted of a periodic discharge generated by a dc square wave voltage source, synchronized with the optical multichannel analyzer of the spectrometer through its TTL (transistor-transistor logic) level pulse. The periodicity of the discharge under similar physical conditions allows accumulation the spectroscopic information for each cycle, making possible a time resolution of tens of milliseconds by increasing the resulting intensity profile of the spectra     

SZ-4飞船辐射模态沙漠地区数据模拟验证

对SZ-4飞船辐射模态获取的亮温数据,进行了模拟研究。辐射模态的工作频率范围为6．6～37GHz,对应的地面像元尺寸为6～32km。以新疆塔中地区为研究对象,通过分析被动微波遥感中裸露地表的辐射特性,基于裸露地表的辐射模型（AIEM模型）和地表的实测属性数据来模拟该地区的辐射亮温值,并将其与SZ-4辐射模态和AMSR-E实际的亮温观测值进行了比较,通过对正演结果的比较分析检验了SZ-4亮温数据的质量及其在沙漠地区反演地表参数的潜力。     

Nichtinvasive Elektronendichtemessungen an technischen Plasmen mittels 26,5 GHz-Mikrowellen-Interferometrie

Non-invasive measurements of the electron density in technical plasmas using 26,5 GHz microwave interferometry Plasma diagnostics using microwave interferometry is discussed in comparison to the more traditional Langmuir probe diagnostics. A newly developed microwave interferometer, MWI 2650, available from JE PlasmaConsult GmbH is presented. This device uses a coaxial cable instead of a rigid wave guide for the reference path, giving more flexibility for different reactor geometries. A direct display of the electron density and a calibrated output for an oscilloscope make this device easy to operate. Besides measurements in chemically reactive and deposition plasmas, where Langmuir probes often fail, the MWI 2650 allows to measure the electron density in pulsed plasmas with high temporal resolution and high sensitivity. An electron density peak in the afterglow of dusty as well as electronegative plasmas has been detected for the first time using this device. A special version of the MWI 2650 is also suited for the diagnostics of atmospheric pressure plasmas.     

Langmuir probe diagnostic for measurement of recombination rates of positive ions with electrons in stationary afterglow system

We attempted to compare several probe theories that described collection of charged particles by Langmuir probe at elevated pressures. We used stationary afterglow environment with well-defined ionic composition to measure the electron density as a function of time. Afterglow plasma has the advantage that probability of secondary electron emission from probe surface when the probe works in positive ion acceleration regime is negligible and hence the probe data are more dependable. Since estimation of the rate of recombination required knowledge of absolute values of plasma density, we were able, in case of the ions the rate of recombination of which was known, to calculate the electron density, which corresponded to the known rate of recombination. Consequently we were able to compare apparent electron density calculated from the probe data using different theories with the “reference” electron density that we obtained from the known rate of recombination. Up to several mbar pressure the differences between the “reference” value of electron density and value calculated using the collisionless theories of electron collection by Langmuir probe stay within reasonable error limits.     

天然多糖基室温磷光油墨的制备及防伪应用

目的 为解决常规发光防伪油墨环境不友好，防伪性能单一等问题，以生物基材料为刚性主体结构，芳香磺酸类化合物为客体分子制备水性生物基室温磷光油墨，探索其性能调控因素及包装防伪应用性能。方法 将生物基材料与芳香磺酸类化合物溶于水中获得室温磷光油墨，调控油墨组分、含量等因素，研究其对油墨黏度、油墨层磷光性能的作用机理，并套印不同发光颜色、余辉时长的防伪油墨，获得多色、动态发光的防伪图案，挖掘其包装防伪应用潜力。结果 实验表明，在水性油墨中，生物基材料添加的质量分数为8%，芳香磺酸类化合物添加量为0.16%时，油墨干燥后获得最佳的长余辉发光效果；使用模板刮涂方式印刷防伪图案，模板厚度为0.5mm时，防伪图案综合效果最佳。结论 具有丰富氨基、羟基等基团的生物基材料（如羧甲基壳聚糖、海藻酸钠），能形成具有强氢键作用的刚性结构，有效抑制芳香磺酸类化合物的非辐射跃迁，提升了所制备油墨的发光寿命和效率，有效提升了包装防伪油墨的环境友好度及防伪性能。     

Chemical-reaction dependence of plasma parameter in reactive silane plasma

Electron temperature in a silane glow-discharge plasma, being an important plasma parameter for determining photo-induced instability in the resulting hydrogenated amorphous silicon (a-Si:H), has been studied under various film-preparation conditions. We have used an optical-emission-intensity ratio of Si^* to SiH^* (I_si*/I_siH^*) which corresponds to the high-energy-tail slope of the electron-energy-distribution function in the plasma as a measure of electron temperature in a reactive silane glow-discharge plasma. We have found quite differently from the conventional non-reactive glow-discharge plasma such as hydrogen plasma that the electron temperature in the silane plasma is strongly modified by the substrate temperature (gas temperature) especially under high silane-gas partial-pressure condition. This anomalous behavior of the electron temperature in the silane plasma has been explained by means of gas-phase-polymerization reaction and electron-attachment process to the polymers in the plasma. The electron temperature has been remarkably reduced when a hydrogen-dilution method and a cathode-heating method are used which are considered to control polymer-formation reactions in the silane plasma together with utilization of conventional electron-temperature-controlling methods such as a very high plasma-excitation frequency and an application of magnetic field for electron-confinement. As a consequence of the reduction of electron temperature in the silane plasma, highly stabilized a-Si:H has been successfully obtained even under high growth rate conditions of 1.5 nm s^-1.     

7047584余辉等离子体对PVC吸附FIB的抑制作用

为改善聚氯乙烯(PVC)的抗凝血性,采用余辉等离子体修饰PVC表面,通过扫描电子显微镜(SEM)、接触角、X射线光电子能谱分析(XPS)和散射比浊法等方法,研究了余辉等离子体和放电区等离子体修饰前后的PVC表面形貌、亲水性和化学成分的变化,分析了余辉等离子体和放电区等离子体对PVC吸附血浆中纤维蛋白原(FIB)的影响.结果表明,余辉等离子体对PVC的刻蚀作用较弱,余辉等离子体修饰PVC的亲水性更强,其表面生成了更多的含氧官能团,对纤维蛋白原的抑制吸附明显,表现出好的血液相容性.     

HY-2卫星扫描微波辐射计多通道分辨率匹配技术研究

星载微波辐射计多通道海洋参数反演需要基于同一位置、同一分辨率的多通道观测值,但由于星载微波辐射计设计的局限性,多通道观测地面像元位置和分辨率均不同,因此运用多通道分辨率匹配技术统一观测面元是扫描微波辐射计数据处理中的关键技术,基于海洋二号(HY-2)卫星扫描微波辐射计的成像原理和天线方向图,模拟各通道天线方向图在地面的投影,用Backus-Gilbert(BG)算法将高频观测亮温重采样到最低的低频6.6 GHz通道的观测位置和像元分辨率。结果表明,BG降低分辨率重采样算法能得到很好的拟合效果,并且不另引入噪声。     

Chemical-reaction dependence of plasma parameter in reactive silane plasma

Electron temperature in a silane glow-discharge plasma, being an important plasma parameter for determining photo-induced instability in the resulting hydrogenated amorphous silicon (a-Si:H), has been studied under various film-preparation conditions. We have used an optical-emission-intensity ratio of Si¹ to SiH¹ (I_Si¹/I_SiH¹) which corresponds to the high-energy-tail slope of the electron-energy-distribution function in the plasma as a measure of electron temperature in a reactive silane glow-discharge plasma. We have found quite differently from the conventional non-reactive glow-discharge plasma such as hydrogen plasma that the electron temperature in the silane plasma is strongly modified by the substrate temperature (gas temperature) especially under high silane-gas partial-pressure condition. This anomalous behavior of the electron temperature in the silane plasma has been explained by means of gas-phase-polymerization reaction and electron-attachment process to the polymers in the plasma. The electron temperature has been remarkably reduced when a hydrogen-dilution method and a cathode-heating method are used which are considered to control polymer-formation reactions in the silane plasma together with utilization of conventional electron-temperature-controlling methods such as a very high plasma-excitation frequency and an application of magnetic field for electron-confinement. As a consequence of the reduction of electron temperature in the silane plasma, highly stabilized a-Si:H has been successfully obtained even under high growth rate conditions of 1.5 nm s⁻¹.     

Laser ablation coupled to a flowing atmospheric pressure afterglow for ambient mass spectral imaging

A plasma-based ambient desorption/ionization mass spectrometry (ADI-MS) source was used to perform molecular mass spectral imaging. A small amount of sample material was ablated by focusing 266 nm laser light onto a spot. The resulting aerosol was transferred by a nitrogen stream to the flowing afterglow of a helium atmospheric pressure glow discharge ionization source; the ionized sample material was analyzed by a Leco Unique time-of-flight mass spectrometer. Two-dimensional mass spectral images were generated by scanning the laser beam across a sample surface. The total analysis time for a 6 mm (2) surface, which is limited by the washout of the ablation chamber, was less than 30 min. With this technique, a spatial resolution of approximately 20 microm has been achieved. Additionally, the laser ablation configuration was used to obtain depth information of over 2 mm with a resolution of approximately 40 microm. The combination of laser ablation with the flowing atmospheric pressure afterglow source was used to analyze several sample surfaces for a wide variety of analytes and with high sensitivity (LOD of 5 fmol for caffeine).     

Synthesis and afterglow properties of MgAl2O4:Eu2+, Dy3+ nanopowders

The MgAl2O4:Eu2+, Dy3+ nanophosphors with different particle sizes have been synthesized through a simple and inexpensive precipitate approach followed by a post-annealing process. The structure and morphology of the phosphor are characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM). According to XRD and TEM results, the particle size of MgAl2O4:Eu2+, Dy3+ could be controlled via changing the ratio of MgSO4/Al2O3, and the obtained samples possess regular morphology. The afterglow properties of MgAl2O4:Eu2+, Dy3+ nanophosphors as a function of particle sizes are investigated by afterglow decay curves. Compared with the bulk phosphor, the nanophosphors exhibit longer afterglow time and higher initial afterglow intensity. In nanophosphors, there exist numerous defects on their surfaces due to the large surface to volume ratio, which generally act as luminescent killers, while some of which, however, can probably act as traps beneficial for the generation of afterglow. In the nanosized MgAl2O4:Eu2+, Dy3+ phosphor, the thermoluminescence results indeed indicate the existence of more traps which are introduced due to the large surface to volume ratio of nanoparticles and that the high temperature sintering process contributes to the longer afterglow in the nanophosphors.     

Effects of time response on the point spread function of a scanning radiometer

Scanning radiometers on satellites have a finite response time, because of the detector and the associated electronics. The radiometer measurement as it scans over a point source of radiation of unit strength is the point spread function (PSF). The time response causes a widening and skewing of the PSF. The PSF of a scanning radiometer that has well-focused optics together with time responses for the detector and electronic filter is treated in the time domain. The PSF can be expressed in terms of the system time response to a step input. For a first-order system time response, the displacement of the centroid is the product of the system time constant and the scan rate of the radiometer. The electronic filter further displaces the centroid of the PSF by the product of the scan rate and the filter time constant. Also, the width of the PSF in the scan direction will be increased because of the system time response. The minimum resolvable feature is of the order of the width of the PSF, thus the system time response limits the resolution in the scan direction that can be obtained. The analysis is illustrated by applying it to the Clouds and Earth Radiant Energy System experiment scanning radiometer.     

Characterization of an Ar/O2 magnetron sputtering plasma using a Langmuir probe and an energy resolved mass spectrometer

An argon plasma with a small amount of oxygen in a radio-frequency magnetron sputtering system has been studied experimentally. A Langmuir probe has been used to measure the ion density, electron temperature and plasma potential in the plasma, whereas an energy-resolved mass spectrometer has been used to investigate the ions flowing towards the growing film. It has been found that the argon ion density decreases when the oxygen gas is added to the plasma above a certain flow. A discussion on which process is responsible for this effect is presented.     

长余辉蓄光玻璃的制备及其性能研究

利用传统陶瓷制备方法合成了SrAl2O4:Eu,Dy长余辉发光粉体,该磷光体主发射波长位于520nm,余辉时间长达8h以上。并以硼硅酸盐低熔点玻璃为底材,掺杂该发光粉体,在一定温度下烧成,结果制得长余辉蓄光玻璃。研究还表明,烧成温度对该玻璃的发光性能影响较大,随着温度的升高,发光强度及余辉时间明显下降。     

Penning ionization electron spectroscopy in glow discharge: another dimension for gas chromatography detectors

Admixtures to helium of 100 and 5 ppm of nitrogen, and 100 and 10 ppm of carbon monoxide were identified and measured in the helium discharge afterglow using an electrical probe placed into the plasma. For nitrogen and carbon monoxide gases, the measured electron energy spectra display distinct characteristic peaks (fingerprints). Location of the peaks on the energy scale is determined by the ionization energies of the analyte molecules. Nitrogen and carbon monoxide fingerprints were also observed in a binary mixture of these gases in helium, and the relative concentration of analytes has been predicted. The technically simple and durable method is considered a good candidate for a number of analytical applications, and in particular, in GC and for analytical flight instrumentation.     

Chemical imaging using microline laser ablation: performance comparison of Gaussian and flat top lasers

In previous studies, the potential of a microline imaging arrangement for surface characterization of solid samples in air at atmospheric pressure using laser-induced plasma spectrometry (LIPS) has been demonstrated. An improvement of this approach to obtain a uniform ablation along the microline focus that leads to a representative spatial distribution of elements on the sample surface is presented. For this purpose, the influence of beam energy distribution of two types of Nd:YAG pulsed lasers (a Gaussian laser and a flat top laser) on lateral resolution, intensity profiles of elements, chemical distribution maps, and plasma electron temperature has been investigated. As models of homogeneous and compositionally patterned samples, a stainless steel sample and a photovoltaic cell were chosen for this study. The results demonstrated that the Gaussian laser provides the best lateral resolution, but more redeposition at both sides of the microline crater, while the chemical maps obtained with the flat top laser matched with the distribution of the constituents of the sample surface.     

Formation de polymères dans une décharge radio fréquence: influence de la densité électronique

The polymerization of organic vapours has been studied in a radio frequency plasma (14 MHz) whose electron density has been measured by a resonant cavity method. Changes in the electron density were brought about by modification of the energy input.At constant pressure the rate of deposition has been found to be proportional to the electron density. This is true at different pressures and with such different monomers as styrene and methane.The deposition rate was modified by the introduction of a background gas into the organic plasma, and this was attributed to changes in electron density and temperature. As an illustration, at the same total pressure, monomer partial pressure and electron density, the deposition rate was greater with hydrogen than with nitrogen as a background gas, corresponding to the well-known higher electron temperature in a hydrogen plasma.