Microscope Spectrophotometry Research Articles

光谱法检测玻璃物证的研究

利用紫外可见分光光度法、显微分光光度法以及红外光谱法建立了直接测定玻璃样品的分析方法。通过紫外可见分段光光谱、显微可见分段光光谱以及红外光光谱测定36种玻璃样品，并对比了三种方法。实验结果表明，三种光谱法测定玻璃物证方便简洁，精度高，且各有特点，相互补充，可以有效的鉴定不同种类和不同厚度的玻璃样品，从而为刑事案件现场玻璃样品检验提供科学的方法，为司法实践工作提供有力证据。 The method of direct determination of glass samples was established by UV-Vis spectrophotometry, microscopic spectrophotometry and infrared spectrophotometry. Through UV visible section light spectrum, microscopic visible section light spectrum and infrared light spectrum, 36 kinds of glass samples were measured, and the three methods were compared. The results showed that the methods were simple and concise and of high precision; each had its own characteristics and complemented each other; they even could effectively identify glass samples of different kinds and different thicknesses. This paper has provided scientific method for the inspection of glass samples in criminal cases, and provided strong evidence for the practice of judicial practice.

Muscle iridescence in yellowfin tuna (Thunnus albacares)

Microscope spectrophotometry was used to investigate strong iridescence in yellowfin tuna steaks. Iridescence was restricted to the axes of transversely sectioned myofibers. Sometimes groups of adjacent myofibers all had the same iridescent colors, but colors sometimes differed between adjacent myofibers; thus, myofibers were optically isolated. Iridescent colors were not changed by rotating a polarizer in the illumination pathway, nor by rotating a polarizer in the measuring pathway. But when both pathways contained polarizers, and the polarizers were crossed, both specular reflectance from the meat surface and iridescence from within myofibers were completely extinguished. The reflectance spectra of iridescent colors all showed multiple interference peaks, with a strong dependency on angles of illumination and measurement. Thus, iridescence in tuna muscle exhibited the same optical properties as iridescence previously reported in beef; the most likely cause was multilayer interference from A-bands at different depths. If low-order reflective interference from A-bands can cause iridescence, then high-order interference might be a source of pH-related light scattering along myofibers in food myosystems.

Modified Lignification in the Cell Walls of Cad Depressed Poplars

Ultraviolet microscopic spectrophotometry was used to investigate lignification in the secondary cell walls of wood fibers and vessel elements from either wild type or transgenic poplars with depressed activity of cinnamyl alcohol dehydrogenase (CAD). A distinct shoulder at 330 nm was characteristic of the transgenic poplar. Measurements performed after 1) a mild alkali treatment or 2) areduction with sodium borohydride indicated that this shoulder merely resulted from the occurrence of conjugated carbonyl groups in the lignin polymer rather than alkali-soluble cell wall bound phenolic aldehydes. UV absorbance ratios (A330 /A280) measured in the center of secondary walls in the differentiating xylem clearly showed that the structural changes observed in the lignin polymer of transgenic trees occurred very early during lignin deposition. This suggests that, in poplar trees with low CAD activity, cinnamaldehydes are incorporated into lignin even at the early stages of lignification.

Application of interferometry for 3-dimensional visualization of MgO-layer erosion in a.c.-plasma display panels

We applied the microscopic spectrophotometry for the in situ and real-time investigation of the MgO-layer erosion in an a.c.-plasma display panel cell. In particular, the 3-dimensional visualization of the temporal variation of the MgO-layer thickness was realized from measuring the transmission spectra corresponding to the area of 10×10 μm 2 while scanning the sample position using the stepping motor and the micrometer. The main features of the MgO-layer erosion were the formation of two trenches, the bottom of which were near but not coincide with the edges of indium tin oxide (ITO) electrodes, and the re-deposition of the eroded MgO in the region between two ITO electrodes. We discussed the temporal variation of the trench shape and size in detail. Moreover, we presented the correlation between the amount of the eroded and re-deposited MgO.

Microscope Spectrophotometry with a Continuous Interference Filter

Operating principles are described for microscope spectrophotometry using a continuous interference filter (CIF) powered by a DC motor operated from programmable relays and a multimeter. Optical fibers illuminated from green and red helium-neon lasers were used for calibration. A relatively slow “step, stop and measure” method for scanning through the spectrum was compared with continuous scanning, making measurements as the CIF was moving. Two vectors for wavelength and light intensity were integrated in a stepwise manner (31 wavelengths from 395 nm to 705 nm with a band-pass of 10 nm). The methods were tested against the difficult operating conditions created by measuring reflectance spectra through optical fibers, where there was a crossover between illuminating and measuring pathways and a restricted dynamic range of the photomultiplier at the edges of the spectrum. Both methods gave equally acceptable results with good operating conditions, and equally unacceptable results with bad operating conditions.

Reflectance spectroscopy of interplanetary dust particles

Abstract Reflectance spectra were collected from chondritic interplanetary dust particles (IDPs), a polar micrometeorite, Allende (CV3) meteorite matrix, and mineral standards using a microscope spectrophotometer. Data were acquired over the 380–1100 nm wavelength range in darkfield mode using a halogen light source, particle aperturing diaphrams, and photomultiplier tube (PMT) detectors. Spectra collected from titanium oxide (Ti4O7), magnetite (Fe3O4), and Allende matrix establish that it is possible to measure indigenous reflectivities of micrometer‐sized (>5 μm in diameter) particles over the visible (VIS) wavelength range 450–800 nm. Below 450 nm, small particle effects cause a fall‐off in signal into the ultraviolet (UV). Near‐infrared (IR) spectra collected from olivine and pyroxene standards suggest that the ∼1 μm absorption features of Fe‐bearing silicates in IDPs can be detected using microscope spectrophotometry.Chondritic IDPs are dark objects (<15% reflectivity) over the VIS 450–800 nm range. Large (>1 μm in diameter) embedded and adhering single mineral grains make IDPs significantly brighter, while surficial magnetite formed by frictional heating during atmospheric entry makes them darker. Most chondritic smooth (CS) IDPs, dominated by hydrated layer silicates, exhibit generally flat spectra with slight fall‐off towards 800 nm, which is similar to type CI and CM meteorites and main‐belt C‐type asteroids. Most chondritic porous (CP) IDPs, dominated by anhydrous silicates (pyroxene and olivine), exhibit generally flat spectra with a slight rise towards 800 nm, which is similar to outer P and D asteroids. The most C‐rich CP IDPs rise steeply towards 800 nm with a redness comparable to that of the outer asteroid object Pholus (Binzel, 1992). Chondritic porous IDPs are the first identified class of meteoritic materials exhibiting spectral reflectivities (between 450 and 800 nm) similar to those of P and D asteroids.Although large mineral grains, secondary magnetite, and small particle effects complicate interpretation of IDP reflectance spectra, microscope spectrophotometry appears to offer a rapid, nondestructive technique for probing the mineralogy of IDPs, comparing them with meteorites, investigating their parent body origins, and identifying IDPs that may have been strongly heated during atmospheric entry.

Microscope spectrophotometric study of GaAs/AlxGa1-xAs MBE structures

A series of GaAs/AlxGa1-xAs MBE structures, in which x ranged from 0.10 to 0.40, was studied using microscope spectrophotometry (MSP). The MSP reflectance measurements were found to be extremely sensitive to compositional variation, with a clear inverse relationship between Al content and reflected intensity, and a sympathetic relationship between composition and dispersion. Theoretical optical models were simulated and fitted to the measured data to give layer dimensions which fitted remarkably well with SIMS data. It is concluded that MSP has great potential for the non-destructive metrology and quality control of simple and complex multilayer structures.

Nondestructive characterization of SIMOX structures

In this paper we show how the technique of microscope-spectrophotometry (MSP) may be used to characterize SIMOX structures nondestructively. A range of SIMOX materials prepared using various implantation conditions were investigated. The structural parameters elucidated using MSP included: silicon overlayer and buried oxide thicknesses; approximate densities of silicon islands in the buried oxide layer and silicon dioxide islands in the silicon overlayer as appropriate. These results compared favourably with those obtained using XTEM and indicates that MSP is a reliable technique for the nondestructive, three dimensional characterization of complex multi-layer structures. Furthermore, the technique is capable of examining very small areas (1 μm) which should enable device structures and local inhomogeneities to be characterized.

Non-destructive characterization of thin film SIMOX structures using microscope spectrophotometry

Separation by implanted oxygen (SIMOX) substrates suitable for the fabrication of thin film fully depleted devices ( i.e. with silicon overlayer thicknesses of less than 1000 Å) have been produced by low energy (70 keV) oxygen implantation (to doses of 3 × 10 17, 7 × 10 17 and 10 × 10 17 O + cm −2) followed by annealing at 1405 °C for 30 min. Detailed structural analyses of the specimens were carried out, non-destructively, by microscope spectrophotometry (MSP) and, destructively, by cross-sectional transmission electron microscopy (XTEM). The results obtained from the MSP evaluation showed that the structures (produced with doses of 3 × 10 17, 7 × 10 17 and 10 × 10 17 O + cm −2) consist of a thin silicon film overlying a region which varies in structure from discrete oxide precipitates, interwoven by silicon (for the lowest dose), to a continuous oxide layer containing a few silicon islands (for the highest dose). For all of the samples, extremely good fits were obtained between the measured and simulated MSP data, without the need for unjustified fitting parameters. In all cases, the thickness and physical composition of the various layers were found to agree extremely well with those determined, destructively, by XTEM.

Microscopical study on estimation of time since death in skeletal remains

For the purpose of estimating time since death in skeletal remains, postmortem changes in human compact bones were examined by microradiography and electron microscopy. The UV-fluorescence of the peripheral zone of compact bone was also examined by microscopic spectrophotometry. Microradiographic examination revealed no morphological changes in bones left in the open air for long periods, except one of 15 years since death. In bones left in the soil, vacuoles of 5–10 μm diameter, which contained a honeycomb-like structure formed by small vacuoles of 0.5–1 μm diameter, were found in the peripheral zone of the substantia compacta approximately 5 years since death, and in bones of 6 years or more, this change extended to the mid-zone. In bones left in the sea for 4–5 years, vacuoles of 5–10 μm diameter were observed in the outer peripheral zone of the substantia compacta. The relative intensity of UV-fluorescence in bones dwindled with time since death and the correlation coefficient was considerably high.

UV-visible transmission microscope spectrophotometry on X-type zeolites: Part II. Motion of benzene and toluene within zeolite cavities

Comparative UV spectroscopic investigations on benzene- and toluene-loaded zeolite NaX and NiNaX single crystals were carried out. Absorption spectra of both aromatic compounds in different environments were obtained employing the method of microcomputer-controlled microscope spectrophotometry (MMSP) and of microcomputer-driven photon counting for spectroscopy (MPS). Additional high resolution spectra showed a rotational fine structure superimposed on single vibronic bands of benzene and toluene. A quantum theoretical analysis of the spectra indicates the formation of Na +- and Ni 2+-aryl complexes, but a stronger interaction between the aromatic system and the zeolite lattice in the case of NiNaX zeolites.

UV-visible transmission microscope spectrophotometry on x-type zeolites: Part I. Formation of different nickel complexes in zeolite X

Comparative UV-visible spectroscopic investigations on single crystals of nickel(II) salts of D 4h symmetry and of NiNaX zeolites with various nickel contents were carried out. The transmission spectra were recorded by means of a microcomputer-controlled microscope spectrophotometer (MMSP method). The absorption curves of NiNaX zeolites showed different symmetries of nickel(II) complexes within zeolites depending on the degree of ion exchange. An absorption maximum of 260 nm characteristic for nickel(II) complexes of D 4h symmetry was detected only at low degrees of ion exchange, whereas the spectra of highly-exchanged NiNaX zeolites were almost identical to those of octahedral nickel complexes obtained from aqueous solutions of nickel(II) salts. The formation of differently coordinated nickel complexes is discussed in terms of graph theory, assuming various molecular complexes whose graphs represent all relations between the cations and the surrounding zeolite lattice.