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Статті в журналах з теми "Terahertz; t-rays"

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Автор: Grafiati

Опубліковано: 10 грудня 2022

Оновлено: 28 січня 2023

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Withayachumnankul, Withawat, Bernd M. Fischer, and Derek Abbott. "Numerical removal of water vapour effects from terahertz time-domain spectroscopy measurements." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 464, no. 2097 (May 6, 2008): 2435–56. http://dx.doi.org/10.1098/rspa.2007.0294.

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Анотація:

The use of T-rays, or terahertz radiation, to identify substances by their spectroscopic fingerprints is a rapidly moving field. The dominant approach is presently terahertz time-domain spectroscopy. However, a key problem is that ambient water vapour is ubiquitous and the consequent water absorption distorts the T-ray pulses. Water molecules in the gas phase selectively absorb incident T-rays at discrete frequencies corresponding to their molecular rotational transitions. When T-rays propagate through an atmosphere, this results in prominent resonances spread over the T-ray spectrum; furthermore, in the time domain, fluctuations after the main pulse are observed in the T-ray signal. These effects are generally undesired, since they may mask critical spectroscopic data. So, ambient water vapour is commonly removed from the T-ray path by using a closed chamber during the measurement. Yet, in some applications, a closed chamber is not always feasible. This situation, therefore, motivates the need for an optional alternative method for reducing these unwanted artefacts. This paper represents a study on a computational means that is a step towards addressing the problem arising from water vapour absorption over a moderate propagation distance. Initially, the complex frequency response of water vapour is modelled from a spectroscopic catalogue. Using a deconvolution technique, together with fine tuning of the strength of each resonance, parts of the water vapour response are removed from a measured T-ray signal, with minimal signal distortion, thus providing experimental validation of the technique.

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Im, Kwang-Hee, Sun-Kyu Kim, Jong-An Jung, Young-Tae Cho, Yong-Deuck Woo, and Chien-Ping Chiou. "NDE Terahertz Wave Techniques for Measurement of Defect Detection on Composite Panels of Honeycomb Sandwiches." Electronics 9, no. 9 (August 21, 2020): 1360. http://dx.doi.org/10.3390/electronics9091360.

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Terahertz wave (T-ray) technologies have become a popular topic in scientific research over the last two decades, and can be utilized in nondestructive evaluation (NDE) techniques. This study suggests an optimal scanning technique method for honeycomb sandwich composite panels, where skins were utilized with two different skins, namely, carbon fiber-reinforced plastic (CFRP) skin and glass fiber-reinforced plastic (GFRP) skin, as layers of the panel surfaces. Foreign objects were artificially inserted between the skins and honeycomb cells in the honeycomb sandwich composite panels. For this experiment, optimal T-ray scanning methods were performed to examine defects based on the angle between the one-ply thin fiber skin axis and the angle of the electric field (E-field) according to the amount of conductivity of the honeycomb sandwich composite panels. In order to confirm the fundamental characteristics of the terahertz waves, the refractive index values of the GFRP composites were experimentally obtained and analyzed, with the data agreeing with known solutions. Terahertz waves (T-rays) were shown to have limited penetration in honeycomb sandwich composite panels when utilized with a skin of carbon fibers. Therefore, T-rays were found to interact with the electrical conductivity and electric field direction of honeycomb sandwich composite panels with glass fiber skins. The T-ray images were obtained regardless of the electric field direction and the fiber direction. In the honeycomb sandwich composite panels with carbon fiber skins, the T-ray images with higher signal-to-noise (S/N) ratios depended on the scanning angle between the angle of the carbon fiber and the angle of the electric field. Thus, the angle of optimum detection measurement was confirmed to be 90° between the E-field and the fiber direction, particularly when using a carbon fiber skin.

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HU, Q. "TERAHERTZ QUANTUM CASCADE LASERS AND REAL-TIME T-RAYS IMAGING AT VIDEO RATE." International Journal of High Speed Electronics and Systems 18, no. 04 (December 2008): 983–92. http://dx.doi.org/10.1142/s012915640800593x.

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We report our development of terahertz (THz) quantum-cascade lasers with record performance. Using those high-power lasers as the illumination sources and a focal-plane array camera, we are able to perform real-time THz imaging at video rate.

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Mickan, S. P., and X. C. Zhang. "T-Ray Sensing and Imaging." International Journal of High Speed Electronics and Systems 13, no. 02 (June 2003): 601–76. http://dx.doi.org/10.1142/s0129156403001843.

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Terahertz (THz) radiation occupies part of the electromagnetic spectrum between the infrared and microwave bands. Until recently, technology at THz frequencies was under-developed compared to the rest of the electromagnetic spectrum, leaving a gap between millimeter waves and the far-infrared (FIR). In the past decade, interest in the THz gap has been increased by the development of ultrafast laser-based T-ray systems and their demonstration of diffraction-limited spatial resolution, picosecond temporal resolution, DC-THz spectral bandwidth and signal-to-noise ratios above 104. This chapter reviews the development, the state of the art and the applications of T-ray spectrometers. Continuous-wave (CW) THz-frequency sources and detectors are briefly introduced in comparison to ultrafast pulsed THz systems. An emphasis is placed on experimental applications of T-rays to sensing and imaging, with a view to the continuing advance of technologies and applications in the THz band.

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SUN, YIWEN, TIANFU WANG, SIPING CHEN, JIAN ZUO, ZHENWEI ZHANG, and CUNLIN ZHANG. "IMPACT OF DYNAMICAL HYDRATION SHELL AROUND HA PROTEIN ON NONLINEAR CONCENTRATION DEPENDENT T-RAYS ABSORPTION." Journal of Innovative Optical Health Sciences 06, no. 04 (October 2013): 1350047. http://dx.doi.org/10.1142/s1793545813500478.

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T-rays is sensitive to covalently cross-linked proteins and can be used to probe unique dynamic properties of water surrounding a protein. In this paper, we demonstrate the unique absorption properties of the dynamic hydration shells determined by hemagglutinin (HA) protein in terahertz frequency. We study the changes arising from different concentrations in detail and show that nonlinear absorption coefficient is induced by the dynamic hydration water. The binary and ternary component model were used to interpret the nonlinearity absorption behaviors and predict the thickness of the hydration shells around the HA protein in aqueous phase.

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Im, Kwang-Hee, Sun-Kyu Kim, Jong-An Jung, Young-Tae Cho, Yong-Deuck Woo, and Chien-Ping Chiou. "NDE Detection Techniques and Characterization of Aluminum Wires Embedded in Honeycomb Sandwich Composite Panels Using Terahertz Waves." Materials 12, no. 8 (April 17, 2019): 1264. http://dx.doi.org/10.3390/ma12081264.

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For many years, scientists have been aware of the importance of terahertz waves (T-rays), which have now emerged as an NDE (nondestructive evaluation) technique for certain ranges of the electronic spectrum. The present study deals with T-ray scanning techniques of honeycomb sandwich composite panels with a carbon-fiber-reinforced plastic (CFRP) skin as well as the refractive index (n), and the electrical conductivity (α) of glass fiber-reinforced plastic (GFRP) composites. For this experiment, the degree of penetration to FRP composites is investigated for the THz transmitted power based on the angle in the electric field (E-field) direction vs. the direction of the unidirectional carbon fibers. Also, when CFRP skin honeycomb sandwich panels are manufactured for use in aerospace applications, aluminum wires are twisted together into the one-sided surface of the honeycomb sandwich panels to protect against thunderstorms. The aluminum wires are partly visible because they are embedded in the CFRP skin on the honeycomb sandwich panels. After finishing work with a paintjob, the wires become invisible. Thus, detecting the aluminum wires is a key issue for product monitoring. Based on a simple resistor model, an optimal scanning method is proposed to determine the preferred scan orientation on the baseline of the E-field in the direction of fibers to evaluate the level of transmission of T-rays according to the frequency bandwidth. Thus, the combination of angles required to detect the aluminum wires embedded with carbon fibers on the surface of the composite panels can be determined.

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Kovalevska, Larysa, Olexandr Golenkov, Yelyzaveta Kulahina, Todd Callender, Fedir Sizov, and Elena Kashuba. "A Comparative Study on the Viability of Normal and Cancerous Cells upon Irradiation with a Steady Beam of THz Rays." Life 12, no. 3 (March 5, 2022): 376. http://dx.doi.org/10.3390/life12030376.

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Terahertz (THz) electromagnetic radiation is commonly used in astronomy, security screening, imaging, and biomedicine, among other applications. Such approach has raised the question of the influence of THz irradiation on biological objects, especially the human body. However, the results obtained to date are quite controversial. Therefore, we performed a comparative study on the viability of normal cells and cancer cells upon irradiation with a steady beam of THz rays. We used human peripheral blood mononuclear cells and cancer cell lines. Primary human mononuclear blood cells (monocytes, and B-, and T-cells) showed an increased death rate, determined by cell counting and fluorescence microscopy, upon 0.14 THz irradiation. The effect of THz radiation was different among malignant cells of B- and T-cell origin (Ramos and Jurkat cells) and epithelial cancer cells (MCF7 and LNCaP). This was demonstrated by cell counting and by the alamarBlue assay. In conclusion, THz radiation can result in the death of human primary and malignant cells. However, the mechanism of this phenomenon is largely unknown. Hence, more work should be done to shed some light on the mechanism of action of THz irradiation in living organisms to enhance technologic developments.

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Im, Kwang Hee, David K. Hsu, Chien Ping Chiou, and Daniel J. Barnard. "T-Ray NDE Inspections on the Fiber Direction of Thermoplastic PPS-Based CFRP Composites." Advanced Materials Research 650 (January 2013): 253–57. http://dx.doi.org/10.4028/www.scientific.net/amr.650.253.

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Terahertz ray (T-ray) imaging has been emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques, and new application systems are under processing development for the area applications. The terahertz time domain spectroscopy (THz TDS) can be considered as a useful tool using general non-conducting materials; however it is quite limited to conducting materials. In this study, a new time-domain spectroscopy system was utilized for detecting and evaluating layup effect and flaw in FRP composite laminates. In order to solve various material properties, the index of refraction (n) and the absorption coefficient (α) are derived in reflective and transmission configuration using the terahertz time domain spectroscopy. However, the T-ray is limited in order to penetrate a conducting material to some degree. So, investigation of terahertz time domain spectroscopy (THz TDS) was made and reflection and transmission configurations were studied for a 48-ply thermoplastic PPS (poly-phenylene sulfide)-based CFRP solid laminate.

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Im, Kwang-Hee, Je-Woong Park, In-Young Yang, and David Kuei Hsu. "Influence of electric field direction of terahertz radiation on composite materials." Journal of Composite Materials 54, no. 12 (December 26, 2016): 1603–12. http://dx.doi.org/10.1177/0021998316688592.

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Terahertz waves (T-ray) for the non-destructive evaluation were investigated on composite materials. The modalities of the T-ray radiation used were time domain spectroscopy and continuous wave for composites. The composite materials are composed of non-conducting polymeric composites and carbon fiber composites. T-ray signals in the time domain spectroscopy mode resembles that of ultrasound; however, unlike ultrasound, T-ray pulse can detect a crack hidden behind a larger crack (shadow effect). Thick glass fiber reinforced polymer laminates containing double-saw slots was demonstrated. Also, in carbon composites the penetration of T-ray waves was investigated in order to detect flaws is strongly affected by the angle between the electric field vector of the terahertz waves and the intervening fiber directions. Other composites tested in this study include both solid laminates and honeycomb sandwiches. The defects and anomalies investigated by T-ray were foreign material inclusions, simulated disbond and delamination, mechanical impact damage, heat damage, and water or hydraulic fluid ingression. The intensive characterization of T-ray for the non-destructive evaluation of composites are being discussed.

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Im, Kwang Hee, Sun Kyu Kim, David K. Hsu, and Jong An Jung. "Coating Thickness Characterization of Composite Materials Using Terahertz Waves." Materials Science Forum 878 (November 2016): 70–73. http://dx.doi.org/10.4028/www.scientific.net/msf.878.70.

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Анотація:

Recently, terahertz ray imaging has emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques for the area applications. In this study, a new time-domain spectroscopy system was utilized for measuring the coating thickness on CFRP composite laminates. Extensive experimental measurements in reflection mode were made to map out the T-ray images. Also, the refractive index was estimated based on the electromagnetic properties. The CFRP composite laminates were observed in reflection mode and limitations will be discussed in the T-ray processing. By using these characterized material properties, the characteristics was successfully demonstrated for T-ray behavior propagating through the Shim Stock films for acquiring the refractive index. The T-ray technique has been developed for the measurement of the thickness of the Shim Stock films and the coating thickness on CFRP composites. Good results have been obtained in tests made on the thickness of the standard film samples with the coating thickness ranging from around hundreds of μm.

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Park, Je Woong, Kwang Hee Im, David K. Hsu, Chien Ping Chiou, and Daniel J. Barnard. "Terahertz Ray Nondestructive Characterizations in FRP Composites." Advanced Materials Research 123-125 (August 2010): 839–42. http://dx.doi.org/10.4028/www.scientific.net/amr.123-125.839.

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Анотація:

Recently, terahertz ray imaging has emerged as one of the most promising new powerful nondestructive evaluation (NDE) techniques, and new application systems are under processing development for the area applications. In this study, a new time-domain spectroscopy system was utilized for detecting and evaluating layup effect and flaw in FRP composite laminates. Extensive experimental measurements in reflection mode were made to map out the T-ray images. Especially in this characterization procedure, we estimated the electromagnetic properties such as the refractive index. Estimates of properties are in good agreement with known data. Furthermore layup effect and flaw of FRP composite laminates were observed in reflection mode and limitations will be discussed in the T-ray processing.

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Han, Seong-Tae, Antonio C. Torrezan, Jagadishwar R. Sirigiri, Michael A. Shapiro, and Richard J. Temkin. "Real-time, T-ray imaging using a sub-terahertz gyrotron." Journal of the Korean Physical Society 60, no. 11 (June 2012): 1857–61. http://dx.doi.org/10.3938/jkps.60.1857.

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Xin, Yu, Hassan Yousefi Oderji, Ran Hai, and Hong Bin Ding. "Molecular Dynamics Simulation on Terahertz Spectra of Methamphetamine Hydrochloride." Advanced Materials Research 760-762 (September 2013): 35–39. http://dx.doi.org/10.4028/www.scientific.net/amr.760-762.35.

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Methamphetamine hydrochloride crystal (trade name Methedrine) that is one of the illegal drugs used as a stimulant to the nervous system has been considered to be detected by T-ray via the terahertz time-domain spectroscopy (THz-TDS). In this research, we simulated the THz spectra of Methedrine by molecular dynamics methods for the first time. The terahertz spectra at temperatures 78.4K, 200K, 294K and 400K in the frequency range of 10-100cm-1 were investigated, which exhibited the variation of spectra position and intensity with increasing temperature. Firstly, we used DL_POLY simulation package to obtain the instantaneous values of the dipole moment. Subsequently, the intensities of THz vibrational modes were obtained by the Fourier transform of the autocorrelation function of the dipole moment. The results showed our theoretical calculation by molecular dynamics simulations got a good consistency with available experimental spectroscopy. These are useful to determine the best conditions of temperature at which the terahertz time-domain spectroscopy of Methedrine results a highly informative spectrum.

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Im, Kwang-Hee, David K. Hsu, Chien-Ping Chiou, Daniel J. Barnard, Jong-An Jung, and In-Young Yang. "Terahertz Wave Approach and Application on FRP Composites." Advances in Materials Science and Engineering 2013 (2013): 1–10. http://dx.doi.org/10.1155/2013/563962.

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Terahertz (THz) applications have emerged as one of the most new powerful nondestructive evaluation (NDE) techniques. A new T-ray time-domain spectroscopy system was utilized for detecting and evaluating orientation influence in carbon fiber-reinforced plastics (CFRPs) composite laminates. Investigation of terahertz time-domain spectroscopy (THz-TDS) was made, and reflection and transmission configurations were studied as a nondestructive evaluation technique. Here, the CFRP composites derived their excellent mechanical strength, stiffness, and electrical conductivity from carbon fibers. Especially, the electrical conductivity of the CFRP composites depends on the direction of unidirectional fibers since carbon fibers are electrically conducting while the epoxy matrix is not. In order to solve various material properties, the index of refraction (n) and the absorption coefficient (α) are derived in reflective and transmission configurations using the terahertz time-domain spectroscopy. Also, for a 48-ply thermoplastic polyphenylene-sulfide-(PPS-) based CFRP solid laminate and nonconducting materials, the terahertz scanning images were made at the angles ranged from0°to180°with respect to the nominal fiber axis. So, the images were mapped out based on the electrical field (E-field) direction in the CFRP solid laminates. It is found that the conductivity (σ) depends on the angles of the nominal axis in the unidirectional fiber.

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Tanikawa, T., S. Karabekyan, S. Kovalev, S. Casalbuoni, V. Asgekar, S. Bonetti, S. Wall, et al. "Volt-per-Ångstrom terahertz fields from X-ray free-electron lasers." Journal of Synchrotron Radiation 27, no. 3 (April 29, 2020): 796–98. http://dx.doi.org/10.1107/s1600577520004245.

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The electron linear accelerators driving modern X-ray free-electron lasers can emit intense, tunable, quasi-monochromatic terahertz (THz) transients with peak electric fields of V Å−1 and peak magnetic fields in excess of 10 T when a purpose-built, compact, superconducting THz undulator is implemented. New research avenues such as X-ray movies of THz-driven mode-selective chemistry come into reach by making dual use of the ultra-short GeV electron bunches, possible by a rather minor extension of the infrastructure.

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YIN, XIAOXIA, BRIAN W. H. NG, DEREK ABBOTT, BRADLEY FERGUSON, and SILLAS HADJILOUCAS. "APPLICATION OF AUTO REGRESSIVE MODELS OF WAVELET SUB-BANDS FOR CLASSIFYING TERAHERTZ PULSE MEASUREMENTS." Journal of Biological Systems 15, no. 04 (December 2007): 551–71. http://dx.doi.org/10.1142/s0218339007002374.

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This paper presents an approach for automatic classification of pulsed Terahertz (THz), or T-ray, signals highlighting their potential in biomedical, pharmaceutical and security applications. T-ray classification systems supply a wealth of information about test samples and make possible the discrimination of heterogeneous layers within an object. In this paper, a novel technique involving the use of Auto Regressive (AR) and Auto Regressive Moving Average (ARMA) models on the wavelet transforms of measured T-ray pulse data is presented. Two example applications are examined — the classification of normal human bone (NHB) osteoblasts against human osteosarcoma (HOS) cells and the identification of six different powder samples. A variety of model types and orders are used to generate descriptive features for subsequent classification. Wavelet-based de-noising with soft threshold shrinkage is applied to the measured T-ray signals prior to modeling. For classification, a simple Mahalanobis distance classifier is used. After feature extraction, classification accuracy for cancerous and normal cell types is 93%, whereas for powders, it is 98%.

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Paek, Mun-Cheol, Min-Hwan Kwak, Seung-Beom Kang, Sung-Il Kim, Han-Cheol Ryu, Sang-Kuk Choi, Se-Young Jeong, Dae-Won Kang, Dong-Suk Jun, and Kwang-Yong Kang. "Terahertz Time Domain Spectroscopy, T-Ray Imaging and Wireless Data Transfer Technologies." Journal of electromagnetic engineering and science 10, no. 3 (September 30, 2010): 158–65. http://dx.doi.org/10.5515/jkiees.2010.10.3.158.

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Im, Kwang-Hee, Sun-Kyu Kim, Young-Tae Cho, Yong-Deuck Woo, and Chien-Ping Chiou. "THz-TDS Techniques of Thickness Measurements in Thin Shim Stock Films and Composite Materials." Applied Sciences 11, no. 19 (September 24, 2021): 8889. http://dx.doi.org/10.3390/app11198889.

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Terahertz wave (T-ray) scanning applications are one of the most promising tools for nondestructive evaluation. T-ray scanning applications use a T-ray technique to measure the thickness of both thin Shim stock films and GFRP (glass fiber-reinforced plastics) composites, of which the samples were selected because the T-ray method could penetrate the non-conducting samples. Notably, this method is nondestructive, making it useful for analyzing the characteristics of the materials. Thus, the T-ray thickness measurement can be found for both non-conducting Shim stock films and GFRP composites. In this work, a characterization procedure was conducted to analyze electromagnetic properties, such as the refractive index. The obtained estimates of the properties are in good agreement with the known data for poly methyl methacrylate (PMMA) for acquiring the refractive index. The T-ray technique was developed to measure the thickness of the thin Shim stock films and the GFRP composites. Our tests obtained good results on the thickness of the standard film samples, with the different thicknesses ranging from around 120 μm to 500 μm. In this study, the T-ray method was based on the reflection mode measurement, and the time-of-flight (TOF) and resonance frequencies were utilized to acquire the thickness measurements of the films and GFRP composites. The results showed that the thickness of the samples of frequency matched those obtained directly by time-of-flight (TOF) methods.

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Escobar Mejía, Andrés Felipe. "Medición de materiales con radiación Terahertz." Scientia et technica 24, no. 4 (December 30, 2019): 624. http://dx.doi.org/10.22517/23447214.20171.

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La radiación Terahertz (THz) o Rayos T, define las ondas electromagnéticas con un rango de frecuencias entre 0,1 THz y 10 THz. Es posible categorizar las técnicas de detección de radiación en la banda de los THz en técnicas coherentes e incoherentes. La principal diferencia entre ellas es que en la técnica coherente se determinan tanto la amplitud como la fase de la señal recibida; pero, en la técnica incoherente, solo se mide la intensidad de la señal.La espectroscopía THz en el dominio del tiempo es, generalmente un método coherente. Los detectores directos como los piroeléctricos son principalmente detectores incoherentes. Este artículo presenta la medición experimental de diferentes materiales cuando se irradian con radiación de terahertz, aplicando técnicas de espectroscopia THz en el dominio del tiempo. La radiación es emitida por una antena fotoconductora, excitada por un láser de femtosegundos. Los resultados se obtienen al medir el pulso THz transmitido a través de los materiales al implementar sistemas de detección coherentes e incoherentes, al analizar los datos obtenidos, se logró obtener el índice de refracción y coeficiente de absorción, en caso de la técnica coherente, y el coeficiente de absorción en la técnica incoherente, para los distintos materiales estudiados en este trabajo. Con estos resultados se concluye que es posible realizar una caracterización de distintos tipos de materiales al ser irradiados con radiación THz, lo cual conlleva a diversas aplicaciones desde la seguridad hasta el control de calidad.

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WITHAYACHUMNANKUL, WITHAWAT, BRADLEY FERGUSON, TAMATH RAINSFORD, SAMUEL MICKAN, and DEREK ABBOTT. "DIRECT FABRY-PÉROT EFFECT REMOVAL." Fluctuation and Noise Letters 06, no. 02 (June 2006): L227—L239. http://dx.doi.org/10.1142/s0219477506003318.

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This study indicates that the removal of reflections from T-ray signals can be carried out in the frequency domain without prior knowledge of material parameters or sample thickness. By fitting polynomials to the logarithm and the argument of the sample's transfer function, the Fabry-Pérot reflection term is canceled out, leading to disappearance of the reflections in spatial domain. The method successfully removes the reflections for optically thick samples under the condition of noise or amplitude fluctuations. The application to optically thin samples is possible when the samples are subjected to broadband terahertz measurements. The Fabry-Pérot free signal, when used as input to the parameter estimation method, results in correct material parameters with low variance.

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Crosby, Kariah, Aunik Rahman, Kera F. Crawford, Zia Shariat-Madar, Bozena Michniak-Kohn, Donald A. Tomalia, and Anis Rahman. "Critical evaluation of the interaction of special proteins with human stratum corneum via terahertz scanning reflectometry and spectrometry." Precision Nanomedicine 2, no. 2 (March 17, 2019): 256–69. http://dx.doi.org/10.33218/prnano2(2).181218.2.

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Many patients with chronic skin disease develop hemostatic abnormalities. The blood coagulation factor XII is a multifunctional protease, which is involved in thrombosis, fibrinolysis, and inflammatory processes. The aim of this investigation was to assess the autoactivation of FXII that leads to the generation of FXII fragments and their subsequent cell penetration compared to UM8190, a lipophilic selective prolyl carboxypeptidase inhibitor compound. Terahertz scanning reflectometry (TSR) and terahertz spectrometry (TS) were used to study the surface-mediated FXII activation, as well as penetration of the FXII and UM8190, their retardant property, diffusion kinetics and fragmentation profiles into human stratum corneum (SC). From the diffusion kinetics and profiling experiments it was found that FXII does not penetrate the SC but remains mostly on the surface. Compound UM8190 indicates penetration into the SC, as indicated by the increased reflected intensity of T-ray. The terahertz spectral analysis via absorbance spectra indicates that at a low frequency of 0.56 THz a prominent peak occurs due to water or moisture for the SC alone. This peak, however, exhibits a shift for post-diffusion samples of both FXII saturated SC and UM8190-saturated SC. This is indicative of adhesion of these proteins onto the SC. Though this process corroborates the binding of FXII to the cell membrane surface as reported in the in vitro findings, it does not appear to be activated and degraded. It was also found that there are a number of absorbance peaks characteristic for each molecule and these peaks are uniquely shifted relative to each other when compared with the SC alone. Thus, these absorbance peaks may be utilized for assigning identifying features of the protein and peptides in this present study. Further investigation will be conducted for assigning the absorbance peaks to the specific proteins and their resonances.

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Krügener, K., M. Schwerdtfeger, S. F. Busch, A. Soltani, E. Castro-Camus, M. Koch, and W. Viöl. "Terahertz meets sculptural and architectural art: Evaluation and conservation of stone objects with T-ray technology." Scientific Reports 5, no. 1 (October 7, 2015). http://dx.doi.org/10.1038/srep14842.

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SAITO, Yoshito, Kazuhiro Maruyama, Kazuhito Oda, Masanori NAGAO, Shintaro Adachi, Kensei Terashima, Isao Tanaka та Yoshihiko Takano. "Growth and characterization of Bi₂Sr₂Ca_1-xY_xCu₂O_8+δ single-crystal whiskers". Japanese Journal of Applied Physics, 25 квітня 2022. http://dx.doi.org/10.35848/1347-4065/ac6a35.

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Анотація:

Abstract Substitution of Y for Ca in Bi2Sr2CaCu2O8+δ (Bi-2212) system is known to effectively change the hole carrier density. In this paper, we report the growth and characterization of Y-substituted Bi-2212 whisker crystals. The evaluated Y content in the whiskers increased as we increased the nominal Y-ratio in the Bi-Sr-Ca-Y-Cu-Te precursor. The X-ray diffraction patterns of whiskers aligned on a glass plate only showed (00l) Bragg peaks of Bi-2212 phase, indicating that the grown whiskers are single crystalline. The c-axis lattice parameter showed monotonic decrease with Y-substitution. The resistivity of Y-substituted whiskers showed systematic decrease of superconducting transition temperature and increase of normal resistivity, suggesting that the hole carrier density was controlled via Y-substitution. Based on these results, we propose that Bi-2212 with various carrier concentrations can be easily obtained by growing Y-substituted whiskers. Furthermore, such whiskers with controlled T c might be useful for microelectronic applications such as terahertz oscillator.

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