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81.
Yu. V. Zorenko L. N. Limarenko I. V. Nazar M. V. Pashkovskii 《Journal of Applied Spectroscopy》1991,55(5):1100-1103
Translated from Zhurnal Prikladnoi Spektroskopii, Vol. 55, No. 5, pp. 774–778, November, 1991. 相似文献
82.
Chaos and multiple periods are presented for the harmonically excited unsymmetrical spring and damping system with clearance. This paper demonstrates the non-linear behaviour of the motion through simulation and experiment. Intensive care and caution are taken in the experiments to observe the chaos and the multiple periods properly. The focus in this paper is mainly on the change of the bilinear spring stiffness ratio as a prime factor by which chaotic motions occur from quasi-periodic motion. Other investigations and effects on motion are also discussed for the changing of the extent of clearance. The investigations are based on frequency response curves. To understand the dynamics of the non-linearity of this model, all possible data processing and displaying techniques are taken into account. To observe the overall phenomena of this bilinear system, the resonance curves and the bifurcation diagrams are taken thoroughly for a wide frequency region. 相似文献
83.
MK Bhide RM Kadam MD Sastry Ajay Singh Shashwati Sen Manmeet Kaur DK Aswal SK Gupta VC Sahni 《Pramana》2002,58(5-6):799-802
Microwave absorption studies have been carried out on MgB2 superconductor using a standard X-band EPR spectrometer. The modulated low-field microwave absorption signals recorded for
polycrystalline (grain size ∼ 10 μm) samples suggested the absence of weak-link character. The field dependent direct microwave
absorption has been found to obey a ✓H dependence with two different slopes, which indicated a transition from strongly pinned lattice to flux flow regime. 相似文献
84.
85.
Nazar Mohammad Ranjha Jahanzeb Mudassir Naveed Akhtar 《Journal of Sol-Gel Science and Technology》2008,47(1):23-30
In the present work methyl methacrylate-co-itaconic acid (MMA-co-IA) hydrogels were synthesized by free radical copolymerization
of methyl methacrylate (MMA) and itaconic acid (IA) using ethylene glycol dimethacrylate (EGDMA) and methylene bisacrylamide
(MBAAm) as crosslinkers and benzoyl peroxide as initiator. Selected samples were loaded with model drug lactulose. For the
lactulose release, the effect of pH, monomeric compositions, degree of crosslinking were investigated. The release of lactulose
was studied for 8 h period in USP phosphate buffer solutions of varying pH 1.2, 5.5, 6.5 and 7.0. The drug release data were
fitted into various kinetics models like the zero order, first order, Higuchi and Peppas. The release kinetics of lactulose
from MMA/IA hydrogels was found to be best described by the Peppas model. Results showed that drug release increased by increasing
IA content in the hydrogels but the effect of changing of crosslinking ratio on drug release was not significant. The surface
morphology of MMA/IA drug loaded hydrogel was studied by SEM which revealed uniform distribution of the drug in the hydrogels.
In conclusion, it can be said that lactulose can be successfully incorporated into crosslinked MMA/IA hydrogels and its release
can be modulated by changing the mole fraction of the acid component in the gels. 相似文献
86.
Dr. Tong-Tong Zuo Dr. Felix Walther Jun Hao Teo Dr. Raffael Rueß Yubo Wang Prof. Marcus Rohnke Prof. Daniel Schröder Prof. Linda F. Nazar Prof. Jürgen Janek 《Angewandte Chemie (International ed. in English)》2023,62(7):e202213228
Lithium argyrodite-type electrolytes are regarded as promising electrolytes due to their high ionic conductivity and good processability. Chemical modifications to increase ionic conductivity have already been demonstrated, but the influence of these modifications on interfacial stability remains so far unknown. In this work, we study Li6PS5Cl and Li5.5PS4.5Cl1.5 to investigate the influence of halogenation on the electrochemical decomposition of the solid electrolyte and the chemical degradation mechanism at the cathode interface in depth. Electrochemical measurements, gas analysis and time-of-flight secondary ion mass spectrometry indicate that the Li5.5PS4.5Cl1.5 shows pronounced electrochemical decomposition at lower potentials. The chemical reaction at higher voltages leads to more gaseous degradation products, but a lower fraction of solid oxygenated phosphorous and sulfur species. This in turn leads to a decreased interfacial resistance and thus a higher cell performance. 相似文献
87.
Arsou Arimi Mehrdad Farhadian Ali Reza Solaimany Nazar Maryam Homayoonfal 《Research on Chemical Intermediates》2016,42(5):4021-4040
In the current study, a nanophotocatalyst doped with of TiO2 and Fe2O3 nanoparticles supported on Iranian clinoptilolite was synthesized and characterized by XRD, XRF, SEM, and EDX analyses. The results suggested the successful loading of TiO2 and Fe2O3 nanoparticles onto the surface of clinoptilolite. The SEM images confirmed the average size of nanoparticles deposited on zeolite, which was about 20–40 nm. Furthermore, application of the synthesized photocatalyst in photocatalytic degradation of Acid Black 172 dye was studied using the Taguchi method and the chosen parameters were as follows: pH (2–7), dye concentration (50–200 mg/l), irradiation time (30–120 min), and catalyst dosage (0.5–1.5 g/l). The results indicate that dye concentration, pH, and irradiation time are respectively the most effective factors in these experiments while with the minimum dosage of the catalyst (0.5 g/l), up to 90 % removal efficiency could be achieved. The optimum value for each parameter was pH = 2, dye concentration = 50 mg/l, catalyst dosage = 1 g/l and irradiation time = 60 min, and the dye removal efficiency reached up to 100 % at these optimal conditions. Furthermore, after five-times recycling and reusing the catalyst, the efficiency of the photocatalytic degradation was reduced from 91.5 to 65.9 %, which is still an acceptable value. 相似文献
88.
Jens Schoene Hassen Bel Abed Mathias Christmann Marc Nazaré 《Tetrahedron letters》2017,58(16):1633-1635
A versatile two-step, one-pot reaction to access N-substituted-2H-indazol-2-amine derivatives has been elaborated. A diverse set of analogues was obtained by a sequential hydrazone formation and reductive cyclization in moderate to good yields from readily available starting materials. The strategy tolerates a broad range of substitutions pattern and functional groups allowing further derivatizations. 相似文献
89.
Analysis of Voice and Quantitative Measurement of Glottal Gap After Thyroplasty Type I in the Treatment of Unilateral Vocal Paralysis 总被引:2,自引:0,他引:2
Thyroplasty type I is one of several surgical treatments in which improving the voice of unilateral vocal fold paralysis is the ultimate objective. The goal of the surgery is the medialization of the paralyzed vocal fold. The purpose of this study is to evaluate the effectiveness of thyroplasty type I through acoustical analysis, aerodynamic measures, and quantitative videostroboscopic measurements. We report on 20 patients with unilateral vocal cord paralysis who underwent thyroplasty type I. We performed preoperative and postoperative video image analysis (normalized glottal gap area) and computer-assisted voice analysis (fundamental frequency, jitter, shimmer, noise-to-harmonic ratio, mean phonation time, mean flow rate, mean subglottic pressure) in all patients. The glottal gap was significantly reduced after thyroplasty type I. Postoperative voice quality was characterized by an improved pitch and amplitude pertubation (jitter and shimmer), phonation time (mean phonation time), and subglottic pressure (mean subglottic pressure). Thyroplasty type I is an effective method for regaining glottal closure and vocal function. 相似文献
90.
On acoustic and fiberscopic studies of stop consonants, voice onset time and glottal width have been shown to be greatest in heavily aspirated stops, next greater for slightly aspirated stops, and least for unaspirated stops. Integrated activity of the thyroarytenoid and posterior cricoarytenoid muscles has been reported to be involved in differentiating aspirate characteristics of the stops. However, the fine movement of mucosal edges of vocal folds during the production of stops has not been well documented. In recent years, a new method for high-speed digital recording of laryngeal dynamics has made this possible. In the current study, the movements of vocal fold edges were documented during the period of stop production using a fiberscopic system of high-speed digital images. By observing the glottal width and the visual vibratory movements of vocal folds before voice onset, the heavily aspirated stop was characterized as being more prominent and dynamic than the slightly aspirated and unaspirated stops. 相似文献