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41.
A novel device has been proposed which uses a double quantum well structure for the detection of signals in the THz range. The technology for the manufacturing of such devices at this point of time is significantly mature so that such a device may be easily fabricated. The detector frequency may be varied from 10 to 90 THz by changing the well widths from 10 to 30 Å. 相似文献
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随着微分离技术的发展和微电子、微制造技术的进步,芯片分析仪器已成为当今一个重要的发展方向.传统的单通道、单点检测所存在的弊端是检测通量太小. 相似文献
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Fullerene(C60)‐dibenzo‐16‐crown‐5‐oxyacetic acid (DBI6C5‐OCH2‐COOC60) was prepared and applied as the coating material on piezoelectric quartz crystals for detection of various metal ions and polar/nonpolar organic molecules. The C60‐crown ether‐coated piezoelectric crystal sensor with a home‐made computer interface for signal acquisition and data processing was applied as an ion chromatographic (IC) detector for various metal ions, e.g., alkali metal, alkaline earth metal and transition‐metal ions. The piezoelectric detector exhibited quite good sensitivity of 104 ~ 106 Hz/M and good detection limit of 10?3 ~ 10?4 M for these metal ions. The C60‐crown ether piezoelectric detector compared well with the commercial conductivity detector conventionally used for metal ions. The ionic size and ionic charge seemed to have significant effect on the frequency response of the piezoelectric detector. The C60‐crown ether coated piezoelectric crystal sensor was also employed as a high performance liquid chromatographic (HPLC) detector for various polar organic molecules with frequency responses in the order: amines > carboxylic acids > alcohols > ketones. Furthermore, nonpolar organic molecules, e.g., n‐hexane, 1‐hexene and 1‐hexyne, were also detected with this piezoelectric crystal detector. The frequency responses of the piezoelectric crystal detector for these nonpolar organic molecules were in the following order: alkynes > alkenes > alkanes. The effects of solvents and flow rate on the frequency responses of the piezoelectric crystal detector were investigated. The C60‐crown ether coated piezoelectric crystal detector also showed short response time (< 1 min.) and good reproducibility. 相似文献
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Murat Canpolat 《Optik》2011,122(10):887-890
In order to recover distributions of optical parameters of underlining tissues utilizing backreflection optic tomography or diffuse reflectance spectroscopy for diagnostic proposes, trajectories of photons should be correctly estimated within tissue. Therefore, we have simulated the soft tissues with 1% Intralipid emulsion and have determined photon density distribution as a function of depth inside the Intralipid emulsions using laser light of wavelength 808 nm and two different detectors for different source-to-detector (S-D) separations. In this study we have shown difference in path distribution of the detected photons with two different detectors with different sensitivity for the same S-D separations in the Intralipid emulsions. This study has also shown that, the maximum penetration depth (MPD) of the detected photons is not an increasing function of the S-D separations. After reaching a maximum depth, the penetration depth decreases as S-D separation increases. 相似文献
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B. Roth D. Köther A. Beyer 《International Journal of Infrared and Millimeter Waves》1988,9(11):971-981
An electronical system for real-time measurement of scattering parameters of millimeterwave two-ports is described. In order to achieve a suitable measurement accuracy, the output signals of the millimeterwave detectors and the characteristic of the measurement amplifier should be matched. For this reason the detector power-characteristic is approximated by help of a polygon and it is realized with a few nonlinear amplifiers. The theoretical background and experimental results show the applicability of the measurement system presented here. 相似文献
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To design a new radon gas dosemeter, the knowledge of the SSNTD α counting efficiency is essential. It depends primarily on the energy and incidence angle into the detector, then on the etching conditions and finally on the track counting procedure. Therefore the elicited efficiency function represents all these factors. The detectors were exposed to α particles at different angles of incidence and energies, by using a 244Cm source; two alternative NaOH solution etching conditions were tested, 6.25 N 70°C at 6 and 12 h, respectively. The counting was performed with a light microscope, 267×, and with an automatic track analysis procedure. The critical incidence angle dependance on energy, in our standard condition (6 h), resulted θC(E)=380.0e(−0.286•(E−0.050))(1−e(−0.186•(E−0.050))), and it was used to design our new radon gas holder. 相似文献
50.
Combination of chromatographic and chemometric methods to study the interactions between DNA strands
This work describes the combination of size-exclusion chromatography and chemometric resolution methods to study the formation of complex DNA structures from individual strands. This combined procedure has been applied to two different experimental data. Firstly, the formation of an intermolecular Watson–Crick duplex structure formed by the individual unstructured strands. Secondly, the competition between the intermolecular Watson–Crick duplex and intramolecular quadruplex structures formed by two sequences found in the hTERT gene has been studied. 相似文献