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Artigos de revistas sobre o tema "Intrinsic excitation"

Autor: Grafiati
Publicado: 2 de novembro de 2024

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1

Trukhin, A. N. "Energy Transport in SiO2 Crystals: Luminescence Excitation Spectra of Stishovite and α-Quartz". Latvian Journal of Physics and Technical Sciences 59, n.º 4 (1 de agosto de 2022): 19–24. http://dx.doi.org/10.2478/lpts-2022-0030.

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Abstract The migration of elementary electronic excitations was studied in a single crystal of stishovite and compared with migration in a crystal of α-quartz and polycrystalline stishovite powder. The research method is based on comparing the transfer of absorbed energy to luminescence centers, used as detectors of quasiparticles, and the near-surface nonradiative annihilation of electronic excitations. A sign of migration is the appearance of some minima in the photoluminescence (PLE) excitation spectrum in the region of maxima in the intrinsic absorption spectrum. The PLE spectrum of stishovite contains the first minimum at 9.8 eV, indicating the migration of electronic excitations and the existence of an intrinsic absorption band in stishovite at 9.8 eV. In α-quartz, the first minimum in the PLE spectrum is located at 10.5 eV and corresponds well to the intrinsic absorption band of the exciton.
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2

Belsky, A. N., R. Cortes, A. V. Gektin, P. Martin, V. V. Mikhailin e C. Pédrini. "Excitation mechanisms of CsI fast intrinsic luminescence". Journal of Luminescence 72-74 (junho de 1997): 93–95. http://dx.doi.org/10.1016/s0022-2313(97)00028-8.

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3

Sorbello, C., e R. Etchenique. "Intrinsic optical sectioning with upconverting nanoparticles". Chemical Communications 54, n.º 15 (2018): 1861–64. http://dx.doi.org/10.1039/c7cc08443a.

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4

Hizhnyi, Yuriy, S. G. Nedilko, V. Chornii, T. Nikolaenko, I. V. Zatovsky, K. V. Terebilenko e R. Boiko. "Electronic Structure and Luminescence Spectroscopy of M'Bi(MoO4)2 (M' = Li, Na, K), LiY(MoO4)2 and NaFe(MoO4)2 Molybdates". Solid State Phenomena 200 (abril de 2013): 114–22. http://dx.doi.org/10.4028/www.scientific.net/ssp.200.114.

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The mechanisms of intrinsic luminescence in the set of molybdate crystals of MIMIII(MoO4)2 (MI = Li, Na, K; MIII =Bi, Y, Fe) type are revealed in complex experimental and theoretical studies. The luminescence spectroscopy under vacuum ultraviolet (VUV) synchrotron excitations is applied together with the electronic structure calculations carried out by the FLAPW method. The energy gaps (Eg) values of the crystals are determined in simultaneous analysis of diffuse reflectance and luminescence excitation spectra. It is found that the molybdate groups MoO42- play a dominant role in the processes of intrinsic luminescence in studied molybdate compounds
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5

Omagari, Shun, e Martin Vacha. "Toward accurate measurement of the intrinsic quantum yield of lanthanide complexes with back energy transfer". Physical Chemistry Chemical Physics 22, n.º 6 (2020): 3683–90. http://dx.doi.org/10.1039/c9cp06294g.

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6

Wu, Ting, Yiting Tao, Panting Wang, Mingjun Zhao e Danping Chen. "ZnCl2-Enhanced Intrinsic Luminescence of Tin Chlorophosphate Glasses". Photonics 9, n.º 12 (12 de dezembro de 2022): 973. http://dx.doi.org/10.3390/photonics9120973.

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This communication reports the intrinsic luminescence of tin chlorophosphate glasses. The glass maintains the low melting point characteristics of tin fluorophosphate glasses, and exhibits a red-shifted and broadened excitation wavelength peak. Tin chlorophosphate glasses can exhibit a broadband luminescence of 400–700 nm under an excitation of 380–430 nm. Furthermore, the introduction of ZnCl2 into tin chlorophosphate glasses can considerably enhance the luminescence without affecting their low-melting characteristics. The luminescence intensity can be increased fourfold, with the enhancement attributed to the reduced visible absorption, improved dispersion of Sn2+ ions, and the energy exchange between Sn2+ and Zn2+ in the glasses owing to the addition of ZnCl2.
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7

Steiner, T., e M. L. W. Thewalt. "Subnanosecond transient studies of intrinsic and extrinsic luminescence in CdSe". Canadian Journal of Physics 63, n.º 9 (1 de setembro de 1985): 1205–11. http://dx.doi.org/10.1139/p85-197.

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The photoluminescence spectrum and transient behaviour of free and bound excitons in CdSe have been studied with both resonant and above band-gap excitation. The free- and bound-exciton lifetimes were found to be excitation-intensity dependent even at very low levels. In all cases, the free-exciton luminescence decayed more rapidly than that of the bound excitons. A comparison of the no-phonon and longitudinal-optic-phonon replicas of the free-exciton luminescence indicates that the observed doublet structure of the no-phonon spectrum arises from the two polariton branches. Resonant excitation of the donor and acceptor bound excitons revealed two-electron and two-hole replicas, respectively. We believe these to be the first reported two-hole transitions in CdSe. The initial rapid cooling of the free-exciton gas could be observed in a series of time-resolved spectra.
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8

Zhyshkovych, A. V. "Intrinsic and impurity luminescence of CaF2, CaF2:Eu2+ and CaF2:Eu3+ nanoparticles at high energy excitation". Functional materials 21, n.º 1 (30 de março de 2014): 10–14. http://dx.doi.org/10.15407/fm21.01.010.

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9

Wang, Yangbo, Yingdong Han, Runfa Liu, Cunping Duan e Huaiyong Li. "Excitation-Controlled Host–Guest Multicolor Luminescence in Lanthanide-Doped Calcium Zirconate for Information Encryption". Molecules 28, n.º 22 (16 de novembro de 2023): 7623. http://dx.doi.org/10.3390/molecules28227623.

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Efficient control over lanthanide luminescence by regulating excitations offers a real-time and reversible luminescence-managing strategy, which is of great importance and highly desirable for various applications, including multicolor display and information encryption. Herein, we studied the crystal structure, luminescence properties, and mechanisms of undoped and Tb3+/Eu3+-doped CaZrO3 in detail. The intrinsic purple-blue luminescence from host CaZrO3 and the introduced green/red luminescence from guest dopants Tb3+/Eu3+ were found to have different excitation mechanisms and, therefore, different excitation wavelength ranges. This enables the regulation of luminescent color through controlling the excitation wavelengths of Tb3+/Eu3+-doped CaZrO3. Furthermore, preliminary applications for information encryption with these materials were demonstrated using portable UV lamps of 254 and 302 nm. This study not only promotes the development of multicolor luminescence regulation in fixed-composition materials, but also advances the practical applications of lanthanide luminescent materials in visually readable, high-level anti-counterfeiting and information encryption.
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10

Yamayose, Y., Y. Kinoshita, Y. Doi, A. Nakatani e T. Kitamura. "Excitation of intrinsic localized modes in a graphene sheet". Europhysics Letters (EPL) 80, n.º 4 (24 de outubro de 2007): 40008. http://dx.doi.org/10.1209/0295-5075/80/40008.

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11

Martinez Turtos, Rosana, Stefan Gundacker, Marco Pizzichemi, Alessio Ghezzi, Kristof Pauwels, Etiennette Auffray, Paul Lecoq e Marco Paganoni. "Measurement of LYSO Intrinsic Light Yield Using Electron Excitation". IEEE Transactions on Nuclear Science 63, n.º 2 (abril de 2016): 475–79. http://dx.doi.org/10.1109/tns.2016.2527738.

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12

Qaid, Saif M. H., Hamid M. Ghaithan, Khulod K. AlHarbi, Abrar F. Bin Ajaj, Bandar Ali Al-Asbahi e Abdullah S. Aldwayyan. "Investigation of Threshold Carrier Densities in the Optically Pumped Amplified Spontaneous Emission of Formamidinium Lead Bromide Perovskite Using Different Excitation Wavelengths". Photonics 9, n.º 1 (22 de dezembro de 2021): 4. http://dx.doi.org/10.3390/photonics9010004.

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The high crystal quality of formamidium lead bromide perovskite (CH(NH2)2PbBr3 = FAPbBr3) was infiltrated in a mesoporous TiO2 network. Then, high-quality FAPbBr3 films were evaluated as active lasing media, and were irradiated with a picosecond pulsed laser to demonstrate amplified spontaneous emission (ASE), which is a better benchmark of its intrinsic suitability for gain applications. The behavior was investigated using two excitation wavelengths of 440 nm and 500 nm. Due to the wavelength-dependent absorbance spectrum and the presence of a surface adsorption layer that could be reduced using the shorter 440 nm wavelength, the ASE power dependence was strongly reliant on the excitation wavelength. The ASE state was achieved with a threshold energy density of ~200 µJ/cm2 under 440 nm excitation. Excitation at 500 nm, on the other hand, needed a higher threshold energy density of ~255 µJ/cm2. The ASE threshold carrier density, on the other hand, was expected to be ~4.5 × 1018 cm−3 for both excitations. A redshift of the ASE peak was detected as bandgap renormalization (BGR), and a BGR constant of ~5–7 × 10−9 eV cm was obtained.
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13

BANDO, K., I. AKAI, T. KARASAWA, K. INOUE e H. NAKASHIMA. "HIGH DENSITY EXCITATION EFFECTS ON EXCITONS AND ELECTRON-HOLE PAIRS IN AlxGa1-xAs/AlAs QUANTUM WIRES". International Journal of Modern Physics B 15, n.º 28n30 (10 de dezembro de 2001): 3757–60. http://dx.doi.org/10.1142/s0217979201008597.

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High density excitation effects on excitons in Al x Ga 1-x As/AlAs (x=0.2~0.5) quantum wires (QWRs) have been investigated. In these samples, the difference between the type-I (x≤0.3) and type-II (x≥0.4) band structures was clearly observed in high density effects on the photoluminescence (PL) and its temporal response. In the type-I samples, the PL is characterized by a fast radiative decay process reflecting intra-wire transitions. The PL peak shows a small blueshift with increasing excitation density, and the shift becomes large to 20meV under the highest excitation limit. The large shift is ascribed to intrinsic high density excitation effects appearing beyond the weak localization of the excitons ito structural fluctuations. On the other hand, in the type-II PL, a huge blueshift appears, being much larger than the localization energies of the excitons. This shift is also considered to be due to another intrinsic high-density effects brought about by the long-lived type-II excitons.
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14

Aprahamian, Ani, e Shelly R. Lesher. "Low lying oscillations of deformed nuclei". EPJ Web of Conferences 178 (2018): 02009. http://dx.doi.org/10.1051/epjconf/201817802009.

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Low-lying oscillations of the intrinsic deformed shape of a nucleus remain an open challenge in nuclear structure. The question or challenge revolves around the viability of single or multiple quanta of vibrational excitations superimposed on the equilibrium, deformed shape of a nucleus. The K=2 or “γ” vibrations are fairly widespread and nominally conform to expectations whereas the existence of the K=0 or “β” vibrational excitation is yet to be distinguished from other possible origins including the coexistence of other potential minima.
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15

Барышников, В. И., О. В. Горева, Ю. А. Григорьева e О. Л. Никонович. "Фемтосекундное многофотонное возбуждение люминесценции примесных ионов в кристаллах". Журнал технической физики 126, n.º 3 (2019): 336. http://dx.doi.org/10.21883/os.2019.03.47375.230-18.

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AbstractThe mechanism of excitation of the impurity luminescence in crystalline materials under intense femtosecond laser irradiation has been investigated. It is established that a high concentration of band electrons and holes, which are successively captured by impurity ions, is formed during the femtosecond three-photon ionization of the intrinsic crystalline material. The efficiency of electron–hole excitation of the impurity composition in crystals (as for the electron beam irradiation) is determined by the degree of difference between the electron systems of the s , p , and d subgroups of the outer shell of cations of the intrinsic material and activator.
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16

Arguirov, Tzanimir, Martin Kittler, Michael Oehme, Nikolay V. Abrosimov, Oleg F. Vyvenko, Erich Kasper e Jörg Schulze. "Luminescence from Germanium and Germanium on Silicon". Solid State Phenomena 205-206 (outubro de 2013): 383–93. http://dx.doi.org/10.4028/www.scientific.net/ssp.205-206.383.

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We present an overview on generation of direct gap photo- and electroluminescence in Ge bulk wafers, Ge thin films deposited on Si, and Ge p-i-n diodes prepared on Si substrates. We analyzed the emission in a spectral range from 0.45 eV to 0.95 eV, covering the radiation caused by direct gap transitions, the indirect one, and also the luminescence related to transition on dislocations. The temperature and excitation level strongly influence the intensities of direct and indirect photoluminescence in bulk samples. As it could be expected, high temperature and excitation favour the generation of direct gap luminescence. Intrinsic bulk Ge shows a quadratic dependence of the direct gap luminescence on the excitation and a sub-quadratic one for the indirect. The photoluminescence spectra taken from intrinsic Ge on Si layers show features related to dislocations. There are two spectral regions associated with dislocation recombination. At room temperature one is at around 0.45 eV and the other at 0.72 eV. We found strong direct gap radiation from the Ge p-i-n diodes with intrinsic, highly dislocated active area (dislocation density of about 108-1010 cm-2). There is a threshold current density of 8 kA/cm2, at which the direct band luminescence becomes a super-quadratic. The dependence of the radiation intensity on the excitation is governed by a power law with exponent of 1.7 before reaching that threshold and 4.5 after exceeding it. Above the threshold the dislocation radiation shows similar dependence on the excitation as the direct band luminescence.
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17

Lin, Jui-Liang, Manh-Tien Bui e Keh-Chyuan Tsai. "An Energy-Based Approach to the Generalized Optimal Locations of Viscous Dampers in Two-Way Asymmetrical Buildings". Earthquake Spectra 30, n.º 2 (maio de 2014): 867–89. http://dx.doi.org/10.1193/052312eqs196m.

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This paper proposes a simple approach to the generalized optimal locations of linear viscous dampers in elastic two-way asymmetrical buildings under bi-directional ground excitations. The control target used in this optimization process is to maximize the average dissipation rate of the overall strain energy of the two-way asymmetrical building under the ground excitation of two bi-directional unit impulses. The proposed control target, referred to as the smeared damping ratio, is an intrinsic property of the building system. Two advantages of the proposed approach appeal to engineering practice. First, the proposed approach does not require a complicated optimization algorithm. Second, due to the employment of an intrinsic property rather than a certain response parameter as the target performance index, the optimal damper locations resulting from the proposed approach are generalized, which are independent on the characteristics of input ground motions.
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18

Xing, Tong, Ruiheng Liu, Feng Hao, Pengfei Qiu, Dudi Ren, Xun Shi e Lidong Chen. "Suppressed intrinsic excitation and enhanced thermoelectric performance in AgxBi0.5Sb1.5−xTe3". Journal of Materials Chemistry C 5, n.º 47 (2017): 12619–28. http://dx.doi.org/10.1039/c7tc04573e.

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A maximum ZT of 1.25 at 400 K and an average ZT value of approximately 1.03 between 300 and 600 K were achieved in Ag0.002Bi0.5Sb1.498Te3 by successfully suppressing the intrinsic excitation.
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19

Nurakhmetov, T. N., Zh M. Salikhodzha, K. B. Zhangylyssov, A. M. Zhunusbekov, A. Zh Kainarbay, D. H. Daurenbekov, Zh Azmagambetova et al. "Energy transfer of intrinsic electronic excitation to impurities in the CaSO4 − Mn crystal". Eurasian Journal of Physics and Functional Materials 5, n.º 1 (25 de março de 2021): 31–38. http://dx.doi.org/10.32523/ejpfm.2021050104.

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The nature of the impurity emission center and the energy transfer mechanisms from intrinsic electronic excitations to the Mn2+ impurity centers in the CaSO4 − Mn crystal have been investigated. The methods of vacuum ultraviolet, atomic absorption and luminescence spectroscopy are used in a wide temperature range from 5 K to 300 K. The energy transfer of intrinsic electronic excitations to impurity emission centers in CaSO4 − Mn has been detected.
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20

Wang, De-Yin, Chien-Hao Huang, Bing-Ming Cheng, Teng-Ming Chen e Yu-Hua Wang. "Charge transfer luminescence of hafnates under synchrotron vacuum ultraviolet excitation". RSC Adv. 4, n.º 54 (2014): 28632–35. http://dx.doi.org/10.1039/c4ra03481c.

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21

Co’, Giampaolo. "Introducing the Random Phase Approximation Theory". Universe 9, n.º 3 (7 de março de 2023): 141. http://dx.doi.org/10.3390/universe9030141.

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Random Phase Approximation (RPA) is the theory most commonly used to describe the excitations of many-body systems. In this article, the secular equations of the theory are obtained by using three different approaches: the equation of motion method, the Green function perturbation theory and the time-dependent Hartree–Fock theory. Each approach emphasizes specific aspects of the theory overlooked by the other methods. Extensions of the RPA secular equations to treat the continuum part of the excitation spectrum and also the pairing between the particles composing the system are presented. Theoretical approaches which overcome the intrinsic approximations of RPA are outlined.
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22

Rack, Philip D., Jeffrey J. Peterson, Michael D. Potter e Wounjhang Park. "Eu+3 and Cr+3 doping for red cathodoluminescence in ZnGa2O4". Journal of Materials Research 16, n.º 5 (maio de 2001): 1429–33. http://dx.doi.org/10.1557/jmr.2001.0199.

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Cathodoluminescence emission spectra and photoluminescence (PL) excitation spectra were used to evaluate Eu+3 and Cr+3 as activators for red luminescence in ZnGa2O4. In the ZnGa2O4:Eu materials red emission from Eu+3 and blue intrinsic emission were observed. The blue intrinsic emission increased relative the Eu+3 emission with increasing current density and is attributed to preferential current saturation of the Eu+3 activators. In addition, PL excitation measurements revealed that the inefficient energy transfer from the ZnGa2O4 host to the Eu+3 is due to poor spectral overlap between the ZnGa2O4 emission and the Eu+3 absorption. Cr-doping resulted in a saturated red-color, and no host emission was observed over the entire current density regime investigated. The PL excitation of the ZnGa2O4:Cr revealed good overlap between the ZnGa2O4 host and the Cr+3 absorption. Efficient energy transfer to the Cr+3 activators occurs via multipolar interactions.
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23

Wu, Kai, Kuo Lu, Qingsong Li, Yongmeng Zhang, Ming Zhuo, Sheng Yu, Xuezhong Wu e Dingbang Xiao. "Analysis of Parametric and Subharmonic Excitation in Push-Pull Driven Disk Resonator Gyroscopes". Micromachines 12, n.º 1 (6 de janeiro de 2021): 61. http://dx.doi.org/10.3390/mi12010061.

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For micro-electromechanical system (MEMS) resonators, once the devices are fabricated and packaged, their intrinsic quality factors (Q) will be fixed and cannot be changed, which seriously limits the further improvement of the resonator’s performance. In this paper, parametric excitation is applied in a push-pull driven disk resonator gyroscope (DRG) to improve its sensitivity by an electrical pump, causing an arbitrary increase of the “effective Q”. However, due to the differential characteristics of the push-pull driving method, the traditional parametric excitation method is not applicable. As a result, two novel methods are proposed and experimentally carried out to achieve parametric excitation in the push-pull driven DRGs, resulting in a maximum “effective Q” of 2.24 × 106 in the experiment, about a 7.6 times improvement over the intrinsic Q. Besides, subharmonic excitation is also theoretically analyzed and experimentally characterized. The stability boundary of parametric excitation, defined by a threshold voltage, is theoretically predicted and verified by related experiments. It is demonstrated that, when keeping the gyroscope’s vibration at a constant amplitude, the fundamental frequency driving voltage will decrease with the increasing of the parametric voltage and will drop to zero at its threshold value. In this case, the gyroscope operates in a generalized parametric resonance condition, which is called subharmonic excitation. The novel parametric and subharmonic excitation theories displayed in this paper are proven to be efficient and tunable dynamical methods with great potential for adjusting the quality factor flexibly, which can be used to further enhance the resonator’s performance.
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24

Rauch, Matthias, e Herbert A. Schmid. "Functional evidence for subfornical organ-intrinsic conversion of angiotensin I to angiotensin II". American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, n.º 6 (1 de junho de 1999): R1630—R1638. http://dx.doi.org/10.1152/ajpregu.1999.276.6.r1630.

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Using extracellular electrophysiological recording in an in vitro slice preparation, we investigated whether ANG I can be locally converted to the functionally active ANG II within the rat subfornical organ (SFO). ANG I and ANG II (10−8–10−7M) excited ∼75% of all neurons tested with both peptides ( n = 25); the remainder were insensitive. The increase in firing rate and the duration and the latency of the responses of identical neurons, superfused with equimolar concentrations of ANG I and ANG II, were not different. The threshold concentrations of the ANG I- and ANG II-induced excitations were both 10−9M. Inhibition of the angiotensin-converting enzyme by captopril (10−4M; n = 8) completely blocked the ANG I-induced excitation, a 10-fold lower dose was only effective in two of four neurons. The AT1-receptor antagonist losartan (10−5M; n = 6) abolished the excitation caused by ANG I and ANG II. Subcutaneous injections of equimolar doses of ANG I and ANG II (200 μl; 2 × 10−4M) in water-sated rats similarly increased water intake by 2.4 ± 0.5 ( n = 16) and 2.7 ± 0.4 ml ( n = 20) after 1 h, respectively. Control rats receiving saline drank 0.07 ± 0.06 ml under these conditions. Pretreatment with a low dose of captopril (2.3 × 10−3M) 10 min before the injection of ANG I caused a water intake of 2.8 ± 0.5 ml ( n = 10), whereas a high dose of captopril (4.6 × 10−1M) suppressed the dipsogenic response of ANG I entirely ( n = 11). These data provide direct functional evidence for an SFO-intrinsic renin-angiotensin system (RAS) and underline the importance of the SFO as a central nervous interface connecting the peripheral with the central RAS.
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25

PANCHENKO, A. N., V. M. ORLOVSKII e V. F. TARASENKO. "Efficient e-beam and discharge initiated nonchain HF(DF) lasers". Laser and Particle Beams 21, n.º 2 (abril de 2003): 223–32. http://dx.doi.org/10.1017/s0263034603212106.

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The spectral and amplitude-temporal parameters of HF (DF) lasers pumped by nonchain chemical reactions initiated by radially convergent or planar e-beams and self-sustained discharge were studied. Intrinsic efficiency of the HF lasers up to ∼10% was obtained for both excitation methods. It was shown that the high efficiency of an e-beam-initiated HF laser may be attained as a result of the simultaneous formation of atomic and molecular fluorine and of the participation of F2 in population inversion. A laser pulse has a complex profile caused by the successive generation of P-lines and the overlap during the radiation pulse of both the rotational lines of the same vibration band and of individual vibration bands. Experimental conditions providing high intrinsic efficiency of a discharge nonchain HF (DF) laser are determined. Intrinsic efficiency of HF and DF lasers up to ηin ∼ 10% and 7%, respectively, is obtained using excitation by inductive and LC generators in the SF6-H2 (D2) mixtures. High discharge uniformity obtained with the use of special shaped electrodes along with uniform UV preionization is a key parameter for improving the intrinsic efficiency of discharge HF (DF) lasers. It was found that in this excitation condition, output spectra of the HF laser significantly widen and cascade laser action on some rotational lines of the vibrational transitions of HF molecules ν(3–2) → ν(2–1) → ν(1–0) is observed. This can explain the high intrinsic efficiency obtained. Specific output of the discharge HF laser over 8 J/L (140 J/L×atm) and total laser efficiency ηt ∼ 4.5% were achieved. For the discharge DF laser, specific output and total efficiency were as high as 6.5 J/L and 3.2%, respectively.
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26

Charbonneau, S., E. Fortin e J. Beauvais. "Time-resolved photoluminescence in CdIn2S4". Canadian Journal of Physics 65, n.º 3 (1 de março de 1987): 204–7. http://dx.doi.org/10.1139/p87-032.

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Photoluminescence spectra of CdIn2S4 single crystals at 1.8 K under both continuous-wave (CW) and pulsed excitation were obtained. In the latter case, a variable time-window technique was used to observe the time evolution of the spectra between 0 and 100 μs. In contrast to previous studies, four spectral bands were observed under both CW and pulsed, intrinsic or extrinsic excitation. In particular, two bands previously unobserved under extrinsic excitation were detected at 1.35 and 1.68 eV, and have been attributed to donor–acceptor pairs and free-electron to acceptor transitions respectively.
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27

Sreebunpeng, Krittiya, Weerapong Chewpraditkul e Martin Nikl. "Intrinsic Light Yield and Light Loss Coefficient of LuAG: Pr under Excitation with α- and γ-Rays". Key Engineering Materials 675-676 (janeiro de 2016): 768–71. http://dx.doi.org/10.4028/www.scientific.net/kem.675-676.768.

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In this paper we present the scintillation properties of polished Lu3Al5O12: Pr (LuAG: Pr) crystals grown by the Czochralski method. The light yield (LY) and energy resolution were measured using XP5200B photomultiplier under excitation with α - and γ-rays. High LY of 20,800 and 5,700 ph/MeV were obtained at 662 keV γ-rays and 5.5 MeV α-rays, respectively, for a 2 mm thick sample. Light yield dependences on sample thickness were measured under excitation with α - and γ-rays and the intrinsic LY and light loss coefficient were evaluated. The LY ratio under excitation with α - and γ-rays (α/γ ratio) was also determined.
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Febriansyah, Benny, David Giovanni, Sankaran Ramesh, Teck Ming Koh, Yongxin Li, Tze Chien Sum, Nripan Mathews e Jason England. "Inducing formation of a corrugated, white-light emitting 2D lead-bromide perovskite via subtle changes in templating cation". Journal of Materials Chemistry C 8, n.º 3 (2020): 889–93. http://dx.doi.org/10.1039/c9tc05357c.

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A corrugated (110)-oriented 2D Pb–Br perovskite was obtained by systematic modulation of templating dication structure. Upon excitation by UV light, this material exhibits intrinsic “cold” white light emission.
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29

Yu, Ruijin, Aiping Fan, Maosen Yuan, Tianbao Li e Jinyi Wang. "Observation of intrinsic emission in β-BiNbO4 available for excitation of both UV light and high energy irradiation". Physical Chemistry Chemical Physics 18, n.º 34 (2016): 23702–8. http://dx.doi.org/10.1039/c6cp04477h.

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β-BiNbO4 shows photoluminescence and scintillation emission at room temperature. The excitation is from optical transitions from NbO67− groups and 6s(Bi)–4d(Nb) MMCT states; the intrinsic emission is from 3P1 → 1S0 transitions of Bi3+ ions under UV light and X-ray excitation.
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30

Sato, M., H. Furusawa, M. Sakai, Y. Soga e A. J. Sievers. "Experimental investigation of supertransmission for an intrinsic localized mode in a cyclic nonlinear transmission line". Chaos: An Interdisciplinary Journal of Nonlinear Science 32, n.º 3 (março de 2022): 033118. http://dx.doi.org/10.1063/5.0084395.

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In this experimental study of the nonlinear loss mechanism between traveling localized excitation and the underlying extended normal mode spectrum for a 1D lattice, three types of cyclic, electric, nonlinear transmission lines (NLTLs) are used. They are nonlinear capacitive, inductive, and capacitive+inductive NLTLs. To maintain a robust, steady-state traveling intrinsic localized mode (ILM), a traveling wave driver is used. The ILM loses energy because of a resonance between it and the extended NLTL modes. A wake field excitation is detected directly from ILM velocity experiments by the decrease in ILM speed and by the observation of the wake. Its properties are quantified via a two-dimensional Fourier map in the frequency-wavenumber domain, determined from the measured spatial-time voltage pattern. Simulations support and extend these experimental findings. We find for the capacitive+inductive NLTL configuration, when the two nonlinear terms are theoretically balanced, the wake excitation is calculated to become very small, giving rise to supertransmission over an extended driving frequency range.
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31

Creager, W. N., P. L. Richards e A. Zettl. "Far-infrared conductivity ofTaS3: The intrinsic charge-density-wave excitation modes". Physical Review B 44, n.º 8 (15 de agosto de 1991): 3505–8. http://dx.doi.org/10.1103/physrevb.44.3505.

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32

Irie, A., Yu M. Shukrinov e G. Oya. "Experimental observation of the longitudinal plasma excitation in intrinsic Josephson junctions". Journal of Physics: Conference Series 129 (1 de outubro de 2008): 012029. http://dx.doi.org/10.1088/1742-6596/129/1/012029.

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33

BLOCK, D., B. BOULANGER, R. ROMESTAIN, B. DEVEAUD, B. LAMBERT e A. REGRENY. "INTRINSIC VERSUS EXTRINSIC EFFECTS IN EXCITATION DYNAMICS IN GaAs/GaAlAs SUPERLATTICES". Le Journal de Physique Colloques 48, n.º C7 (dezembro de 1987): C7–537—C7–539. http://dx.doi.org/10.1051/jphyscol:19877128.

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34

Gorassini, Monica, Jaynie F. Yang, Merek Siu e David J. Bennett. "Intrinsic Activation of Human Motoneurons: Possible Contribution to Motor Unit Excitation". Journal of Neurophysiology 87, n.º 4 (1 de abril de 2002): 1850–58. http://dx.doi.org/10.1152/jn.00024.2001.

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The main purpose of this study was to estimate the contribution of intrinsic activation of human motoneurons (e.g., by plateau potentials) during voluntary and reflexive muscle contractions. Pairs of motor units were recorded from either the tibialis anterior or soleus muscle during three different conditions: 1) during a brief muscle vibration followed by a slow relaxation of a steady isometric contraction; 2) during a triangular isometric torque contraction; and 3) during passive sinusoidal muscle stretch superimposed on a steady isometric contraction. In each case, the firing rate of a tonically firing control motor unit was used as a measure of the effective synaptic excitation (i.e., synaptic drive) to a slightly higher-threshold test motor unit that was recruited and de-recruited during a contraction trial. The firing rate of the control unit was compared at recruitment and de-recruitment of the test unit. This was done to determine whether the estimated synaptic drive needed to recruit a motor unit was less than the amount needed to sustain firing as a result of an added depolarization produced from intrinsic sources. After test unit recruitment, the firing rate of the control unit could be decreased significantly (on average by 3.6 Hz from an initial recruitment rate of 9.8 Hz) before the test unit was de-recruited during a descending synaptic drive. Similar decreases in control unit rate occurred in all three experimental conditions. This represents a possible 40% reduction in the estimated synaptic drive needed to maintain firing of a motor unit compared with the estimated amount needed to recruit the unit initially. The firing rates of both the control and test units were modulated together in a highly parallel fashion, suggesting that the unit pairs were driven by common synaptic inputs. This tight correlation further validated the use of the control unit firing rate as a monitor of synaptic drive to the test motor unit. The estimates of intrinsically mediated depolarization of human motoneurons (≈40% during moderate contractions) are consistent with values obtained for plateau potentials obtained from intracellular recordings of motoneurons in reduced animal preparations, although various alternative mechanisms are discussed. This suggests that similar intrinsic conductances provide a substantial activation of human motoneurons during moderate physiological activity.
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35

Iwanaga, M., M. Watanabe e T. Hayashi. "Intrinsic luminescence in PbBr2 crystals under one- and two-photon excitation". Journal of Luminescence 87-89 (maio de 2000): 287–89. http://dx.doi.org/10.1016/s0022-2313(99)00317-8.

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36

Afanas’ev, V. P., A. S. Gryazev, P. S. Kaplya e Y. O. Andreyeva. "Intrinsic excitation effect for the Al and Mg samples XPS analysis". Journal of Surface Investigation. X-ray, Synchrotron and Neutron Techniques 10, n.º 1 (janeiro de 2016): 108–12. http://dx.doi.org/10.1134/s102745101506004x.

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37

Ogorodnikov, I. N., V. A. Pustovarov e M. Kirm. "Intrinsic ultraviolet luminescence of LiB3O5 single crystals under inner-shell excitation". Physics of the Solid State 46, n.º 5 (maio de 2004): 842–47. http://dx.doi.org/10.1134/1.1744958.

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38

Butler, P. A., C. Baktash, C. R. Bingham, M. Carpenter, D. Cline, B. Cox, M. W. Guidry et al. "Observation of intrinsic excitation in 160Dy following heavy-ion transfer reactions". Physics Letters B 191, n.º 4 (junho de 1987): 333–38. http://dx.doi.org/10.1016/0370-2693(87)90618-6.

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39

Long, Yang, Jie Ren e Hong Chen. "Intrinsic spin of elastic waves". Proceedings of the National Academy of Sciences 115, n.º 40 (18 de setembro de 2018): 9951–55. http://dx.doi.org/10.1073/pnas.1808534115.

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Unveiling spins of physical systems usually gives people a fundamental understanding of the geometrical properties of waves from classical to quantum aspects. A great variety of research has shown that transverse waves can possess nontrivial spins and spin-related properties naturally. However, until now, we still lack essential physical insights about the spin nature of longitudinal waves. Here, demonstrated by elastic waves, we uncover spins for longitudinal waves and the mixed longitudinal–transverse waves that play essential roles in spin–momentum locking. Based on this spin perspective, several abnormal phenomena beyond pure transverse waves are attributed to the hybrid spin induced by mixed longitudinal–transverse waves. The unique hybrid spin reveals the complex spin essence in elastic waves and advances our understanding about their fundamental geometrical properties. We also show that these spin-dependent phenomena can be exploited to control the wave propagation, such as nonsymmetric elastic wave excitation by spin pairs, a unidirectional Rayleigh wave, and spin-selected elastic wave routing. These findings are generally applicable for wave cases with longitudinal and transverse components.
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40

LEI, YOUMING, e FULI GUAN. "DISORDER INDUCED ORDER IN AN ARRAY OF CHAOTIC DUFFING OSCILLATORS". International Journal of Modern Physics C 23, n.º 10 (outubro de 2012): 1250071. http://dx.doi.org/10.1142/s0129183112500714.

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This paper addresses the issue of disorder induced order in an array of coupled chaotic Duffing oscillators which are excited by harmonic parametric excitations. In order to investigate the effect of phase disorder on dynamics of the array, we take into account that individual uncoupled Duffing oscillator with a parametric excitation is chaotic no matter what the initial phase of the excitation is. It is shown that phase disorder by randomly choosing the initial phases of excitations can suppress spatio-temporal chaos in the system coupled by chaotic Duffing oscillators. When all the phases are the same and deterministic, the oscillators remain chaotic and asynchronous no matter what the common phase is. When driven asynchronously by introducing phase disorder, the oscillators coupled in the array appear more regular with increase of the amplitude of random phase, and the highest level of synchrony between them is induced by intermediate phase disorder, displaying a resonance like phenomenon caused from the transition of the coupled oscillators from chaos to periodic motion. Since varying the initial phases of excitations is more feasible than altering parameters intrinsic to the oscillators coupled in an array, this study provides a practical method for control and synchronization of chaotic dynamics in high-dimensional, spatially extended systems, which might have potential applications in engineering, neuroscience and biology.
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41

Odland, Hans Henrik, Torbjørn Holm, Lars Ove Gammelsrud, Richard Cornelussen e Erik Kongsgaard. "Determinants of LV dP/dtmax and QRS duration with different fusion strategies in cardiac resynchronisation therapy". Open Heart 8, n.º 1 (maio de 2021): e001615. http://dx.doi.org/10.1136/openhrt-2021-001615.

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BackgroundWe designed this study to assess the acute effects of different fusion strategies and left ventricular (LV) pre-excitation/post-excitation on LV dP/dtmax and QRS duration (QRSd).MethodsWe measured LV dP/dtmax and QRSd in 19 patients having cardiac resynchronisation therapy (CRT). Two groups of biventricular pacing were compared: pacing the left ventricle (LV) with FUSION with intrinsic right ventricle (RV) activation (FUSION), and pacing the LV and RV with NO FUSION with intrinsic RV activation. In the NO FUSION group, the RV was paced before the expected QRS onset. A quadripolar LV lead enabled distal, proximal and multipoint pacing (MPP). The LV was stimulated relative in time to either RV pace or QRS-onset in four pre-excitation/post-excitation classes (PCs). We analysed the interactions of two groups (FUSION/NO FUSION) with three different electrode configurations, each paced with four different degrees of LV pre-excitation (PC1–4) in a statistical model.ResultsLV dP/dtmax was higher with NO FUSION than with FUSION (769±46 mm Hg/s vs 746±46 mm Hg/s, p<0.01), while there was no difference in QRSd (NO FUSION 156±2 ms and FUSION 155±2 ms). LV dP/dtmax and QRSd increased with LV pre-excitation compared with pacing timed to QRS/RV pace-onset regardless of electrode configuration. Overall, pacing LV close to QRS-onset (FUSION) with MPP shortened QRSd the most, while LV dP/dtmax increased the most with LV pre-excitation.ConclusionWe show how a beneficial change in QRSd dissociates from the haemodynamic change in LV dP/dtmax with different biventricular pacing strategies. In this study, LV pre-excitation was the main determinant of LV dP/dtmax, while QRSd shortens with optimal resynchronisation.
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42

Nurakhmetov, Turlybek N., Temirulan T. Alibay, Keleshek B. Zhangylyssov, Aibek S. Nurpeissov, Sapargali Pazylbek, Diana Griesiute, Aleksej Zarkov e Aivaras Kareiva. "Luminescence and Electron–Hole-Trapping Centers in α-Ca2P2O7-Mn". Crystals 14, n.º 5 (26 de abril de 2024): 406. http://dx.doi.org/10.3390/cryst14050406.

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The mechanisms of formation of induced intrinsic and impurity radiative states, which consist of intrinsic and impurity electron–hole-trapping center states in irradiated Ca2P2O7-Mn and Ca2P2O7 phosphates, were investigated using thermoactivation and vacuum-ultraviolet spectroscopy methods. These centers are excited at photon energies of 4.0 eV and 4.5 eV, which are within the matrix’s transparency region. New radiative-induced states at 3.06 eV and 2.92 eV are demonstrated to be generated upon the excitation of anions by photons with energies of 5.0 and 5.64 eV. This process is due to charge transfer from the ion to the impurities, specifically Mn2+(O2--Mn2+) and the neighboring ion O 2--(P2O7)4-. Furthermore, upon the excitation of matrix anions with photon energies exceeding the band gap (8.0–8.25 eV), electron-trapping by impurities such as Mn2+ and (P2O7)4- ions results.
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43

Li, Chen Yu, Zhi Cheng, Feng Chen, Yao Hua Du, Long Xue Qiao, Hong Tao Bao e Tai Hu Wu. "Excitation and Emission Wavelength Comparison Study for Bacterial Aerosol Identification Based on Intrinsic Fluorescence". Applied Mechanics and Materials 696 (novembro de 2014): 127–33. http://dx.doi.org/10.4028/www.scientific.net/amm.696.127.

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Background: The rapid and efficient identification of bacterial aerosol become important in clinical application, public health, and manufacturing increasingly. Laser-induced-fluorescence is an important method for identifying bacteria from environmental aerosol. This method is real-time, can operate 24-hour without pretreatment, and even remotely. Objective: Choosing the optimal excitation and emission wavelength and designing an appropriate analysis apparatus fulfill identification of bacterial aerosol. Method: First, fluorescence spectral data of five different strains of bacteria (S.aureus, E.coli, Bacillus subtilis, salmonella, Vibrio Parahaemolyticus) and three types of disruptors (pollen, leave powder, cloth fiber) were obtained by Three-dimensional fluorescent spectrometer. Second, the original spectral data was preprocessed and analyzed in light of common laser wavelength. Last, the optimal excitation and emission wavelength was chosen based on the balance of identification performance and fabricating cost. Result: Experiments showed that choosing ex:266nm/em:354nm and ex:337nm/em:394nm as ex/em wavelength can meet the requirement to identify bacterial aerosol specifically. Furthermore, the 337nm/394nm wavelength had more practical value. Conclusion: Choosing 337nm wavelength laser as excitation light inducing intrinsic the fluorophores within bacterial aerosol and receiving emission fluorescence with 394nm bandpass light filter can differentiate bacteria from disruptors in environmental aerosol efficiently.
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44

Tuerhong, Rouzhaji, Mauro Boero e Jean-Pierre Bucher. "Molecular attachment to a microscope tip: inelastic tunneling, Kondo screening, and thermopower". Beilstein Journal of Nanotechnology 10 (19 de junho de 2019): 1243–50. http://dx.doi.org/10.3762/bjnano.10.124.

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The vibrational excitation related transport properties of a manganese phthalocyanine molecule suspended between the tip of a scanning tunneling microsope (STM) and a surface are investigated by combining the local manipulation capabilities of the STM with inelastic electron tunneling spectroscopy. By attachment of the molecule to the probe tip, the intrinsic physical properties similar to those exhibited by a free standing molecule become accessible. This technique allows one to study locally the magnetic properties, as well as other elementary excitations and their mutual interaction. In particular a clear correlation is observed between the Kondo resonance and the vibrations with a strong incidence of the Kondo correlation on the thermopower measured across the single-molecule junction.
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45

Georges, Joseph. "Continuous-Wave-Laser versus Pulsed-Laser Excitation for Crossed-Beam Photothermal Detection in Small Volume Applications: Comparative Features". Applied Spectroscopy 59, n.º 9 (setembro de 2005): 1103–8. http://dx.doi.org/10.1366/0003702055012645.

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Crossed-beam thermal lens spectrometry can be implemented using continuous-wave- (cw) laser or pulsed-laser excitation. In both cases, the signal depends on the position of the sample with respect to the probe beam waist, the size of the excitation beam, the beam-size ratio into the sample, and the power or energy of the excitation beam. However, due to differences in the rate of formation and relaxation of the thermal lens, both methods exhibit distinct key features. Optimization of the experimental setup and understanding the thermal lens signal are more complicated under cw-laser excitation than with pulsed-laser excitation. Unlike that observed under pulsed excitation, the effect of the excitation beam waist, of the sample size, and of the flow rate are closely related to the effective size of the thermal element and depend on the chopping frequency. Although the intrinsic sensitivities are almost the same, the performance can significantly differ depending on the chopping frequency or pulse repetition rate, which should be high enough to allow fast data collection and efficient signal averaging.
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46

Calendron, Anne-Laure, Emma Kueny, Liwei Song, Giovanni Cirmi, Lars Bocklage, Franz X. Kärtner e Ralf Röhlsberger. "Excitation and control of spin waves in FeBO3 by a strong-field THz pulse". EPJ Web of Conferences 205 (2019): 07008. http://dx.doi.org/10.1051/epjconf/201920507008.

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The dynamically resolved response of the canted-antiferromagnet FeBO3 excited near a magnon resonance shows fast oscillations after THz-excitation’ followed by the magnons’ intrinsic relaxation’ enabling to probe transient magnetic relaxation dynamics over large frequency range.
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47

Wang, Jing, Huoming Shen, Bo Zhang e Juan Liu. "Studies on the dynamic stability of an axially moving nanobeam based on the nonlocal strain gradient theory". Modern Physics Letters B 32, n.º 16 (5 de junho de 2018): 1850167. http://dx.doi.org/10.1142/s0217984918501671.

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In this paper, we studied the parametric resonance issue of an axially moving viscoelastic nanobeam with varying velocity. Based on the nonlocal strain gradient theory, we established the transversal vibration equation of the axially moving nanobeam and the corresponding boundary condition. By applying the average method, we obtained a set of self-governing ordinary differential equations when the excitation frequency of the moving parameters is twice the intrinsic frequency or near the sum of certain second-order intrinsic frequencies. On the plane of parametric excitation frequency and excitation amplitude, we can obtain the instability region generated by the resonance, and through numerical simulation, we analyze the influence of the scale effect and system parameters on the instability region. The results indicate that the viscoelastic damping decreases the resonance instability region, and the average velocity and stiffness make the instability region move to the left- and right-hand sides. Meanwhile, the scale effect of the system is obvious. The nonlocal parameter exhibits not only the stiffness softening effect but also the damping weakening effect, while the material characteristic length parameter exhibits the stiffness hardening effect and damping reinforcement effect.
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48

Funaki, T., K. Nakagawa e T. Hikihara. "The Origin of Nonlinear Phenomena in TCR-SVC Associated With Parametric Excitation of Intrinsic Oscillation and External Excitation". IEEE Transactions on Circuits and Systems I: Regular Papers 55, n.º 9 (outubro de 2008): 2952–58. http://dx.doi.org/10.1109/tcsi.2008.922025.

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49

Schmid, Laura, Thomas Klotz, Oliver Röhrle, Randall K. Powers, Francesco Negro e Utku Ş. Yavuz. "Postinhibitory excitation in motoneurons can be facilitated by hyperpolarization-activated inward currents: A simulation study". PLOS Computational Biology 20, n.º 1 (19 de janeiro de 2024): e1011487. http://dx.doi.org/10.1371/journal.pcbi.1011487.

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Postinhibitory excitation is a transient overshoot of a neuron’s baseline firing rate following an inhibitory stimulus and can be observed in vivo in human motoneurons. However, the biophysical origin of this phenomenon is still unknown and both reflex pathways and intrinsic motoneuron properties have been proposed. We hypothesized that postinhibitory excitation in motoneurons can be facilitated by hyperpolarization-activated inward currents (h-currents). Using an electrical circuit model, we investigated how h-currents can modulate the postinhibitory response of motoneurons. Further, we analyzed the spike trains of human motor units from the tibialis anterior muscle during reciprocal inhibition. The simulations revealed that the activation of h-currents by an inhibitory postsynaptic potential can cause a short-term increase in a motoneuron’s firing probability. This result suggests that the neuron can be excited by an inhibitory stimulus. In detail, the modulation of the firing probability depends on the time delay between the inhibitory stimulus and the previous action potential. Further, the postinhibitory excitation’s strength correlates with the inhibitory stimulus’s amplitude and is negatively correlated with the baseline firing rate as well as the level of input noise. Hallmarks of h-current activity, as identified from the modeling study, were found in 50% of the human motor units that showed postinhibitory excitation. This study suggests that h-currents can facilitate postinhibitory excitation and act as a modulatory system to increase motoneuron excitability after a strong inhibition.
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50

Scherschel, John A., e Michael Rubart. "Cardiovascular Imaging Using Two-Photon Microscopy". Microscopy and Microanalysis 14, n.º 6 (6 de novembro de 2008): 492–506. http://dx.doi.org/10.1017/s1431927608080835.

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AbstractTwo-photon excitation microscopy has become the standard technique for high resolution deep tissue and intravital imaging. It provides intrinsic three-dimensional resolution in combination with increased penetration depth compared to single-photon confocal microscopy. This article will describe the basic physical principles of two-photon excitation and will review its multiple applications to cardiovascular imaging, including second harmonic generation and fluorescence laser scanning microscopy. In particular, the capability and limitations of multiphoton microscopy to assess functional heterogeneity on a cellular scale deep within intact, Langendorff-perfused hearts are demonstrated. It will also discuss the use of two-photon excitation-induced release of caged compounds for the study of intracellular calcium signaling and intercellular dye transfer.
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