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Journal articles on the topic 'Longitudinal-transverse splitting'

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Published: 30 May 2022
Last updated: 31 May 2022

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1

Логинов, Д. К., and А. В. Донец. "Зависимость продольно-поперечного расщепления экситона в квантовой яме от внешнего однородного электрического поля." Физика твердого тела 62, no. 2 (2020): 208. http://dx.doi.org/10.21883/ftt.2020.02.48869.599.

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In our paper theoretical analyzed the decreasing of transverse-longitudinal splitting of an exciton in the GaAs/AlGaAs quantum well in the homogeneous electric field. Also the dependence of the splitting on application field is calculated. The excitonic reflectance spectra of the thick quantum well are calculated for field directed transversal to well layer. The decreasing of reflectance oscillation in the excitonic spectra because of decreasing transverse-longitudinal splitting is demonstrated.
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2

Burak, Ya V., Ya O. Dovgii, and I. V. Kityk. "Longitudinal-transverse splitting of phonon modes in Li2B4O7 crystals." Journal of Applied Spectroscopy 52, no. 1 (January 1990): 97–100. http://dx.doi.org/10.1007/bf00664791.

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3

Andreani, L. C., F. Bassani, and A. Quattropani. "Longitudinal-transverse splitting in Wannier excitons and polariton states." Il Nuovo Cimento D 10, no. 12 (December 1988): 1473–86. http://dx.doi.org/10.1007/bf02454213.

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4

Eda, Kazuo. "Longitudinal-transverse splitting effects in IR absorption spectra of MoO3." Journal of Solid State Chemistry 95, no. 1 (November 1991): 64–73. http://dx.doi.org/10.1016/0022-4596(91)90376-s.

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5

Vdovych, A. S. "Longitudinal and Transverse Electrocaloric Effects in Glycinium Phosphite Ferroelectric." Ukrainian Journal of Physics 66, no. 5 (May 28, 2021): 412. http://dx.doi.org/10.15407/ujpe66.5.412.

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A modified proton ordering model of glycinium phosphite ferroelectric, which involves the piezoelectric coupling of the proton and lattice subsystems, is used for the investigation of the electrocaloric effect. The model also accounts for the dependence of the effective dipole moment on a hydrogen bond on an order parameter, as well as a splitting of parameters of the interaction between pseudospins in the presence of shear stresses. In the two-particle cluster approximation, the influence of longitudinal and transverse electric fields on components of the polarization vector and the dielectric permittivity tensor, as well as on thermal characteristics of the crystal, is calculated. Longitudinal and transverse electrocaloric effects are studied. The calculated electrocaloric temperature change is quite small, about 1K; however, it can change its sign under the influence of a transverse field.
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6

Yu, Yang, and Jian-Feng Li. "The constraint equation of the vertex function of quantum anomaly and Dyson–Schwinger equations in massless QED2 theory." Modern Physics Letters A 35, no. 18 (May 26, 2020): 2050146. http://dx.doi.org/10.1142/s0217732320501461.

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In this paper, we calculate the quantum anomaly for the longitudinal and the transverse Ward–Takahashi (WT) identities for vector and axial-vector currents in QED2 theory by means of the point-splitting method. It is found that the longitudinal WT identity for vector current and transverse WT identity for axial-vector current have no anomaly while the longitudinal WT identity for axial-vector current and the transverse WT identity for vector current have anomaly in QED2 theory. Moreover, we study the four WT identities in massless QED2 theory and get the result that the four WT identities together give the constraint equation of the vertex function of quantum anomaly. At last, we discuss the Dyson–Schwinger equations in massless QED2 theory. It is found that the vertex function of the quantum anomaly has corrections for the fermion propagator and Schwinger model.
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7

Ivchenko, E. L., V. P. Kochereshko, P. S. Kop'ev, V. A. Kosobukin, I. N. Uraltsev, and D. R. Yakovlev. "Exciton longitudinal-transverse splitting in GaAs/AlGaAs superlattices and multiple quantum wells." Solid State Communications 70, no. 5 (May 1989): 529–34. http://dx.doi.org/10.1016/0038-1098(89)90944-7.

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8

Maringa, Maina, and LM Masu. "The effects of different fibre packing geometries on the transverse matrix strain magnification and fibre strain reduction in uniaxially aligned continuous fibre-reinforced composites." Journal of Composite Materials 50, no. 29 (July 28, 2016): 4159–70. http://dx.doi.org/10.1177/0021998316631701.

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Expressions for transverse matrix strain magnification and fibre strain reduction are derived for square and hexagonal fibre array reinforced composites. Respective transverse matrix and fibre strain magnification and reduction, for the square arrays are shown to be higher for all reinforcing fibre volume fractions than those for the hexagonal arrays. The respective magnification and reduction of the transverse matrix and fibre strains are shown to decrease with increasing values of the ratio of elastic modulus ( Em/ Ef) for both reinforcing fibre arrays. The magnified transverse matrix strains in axially loaded longitudinally aligned continuous fibre-reinforced composites are shown to be higher than the applied longitudinal strains for all square array reinforcing fibre volume fractions and for all hexagonal array reinforcing fibre volumes fractions above 31%. This raises possibilities of longitudinal matrix splitting before interfacial bond failure and transverse matrix failure, in a strain based rather than stress-based failure mode.
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9

Yamamoto, Kiyoshi, and Akio Masui. "TO-LO Splitting in Infrared Spectra of Thin Films." Applied Spectroscopy 50, no. 6 (June 1996): 759–63. http://dx.doi.org/10.1366/0003702963905709.

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The importance of transverse optic-longitudinal optic (TO-LO) splitting in the interpretation of infrared spectra of thin films is experimentally presented. When infrared spectra are observed at oblique angles of incidence, the shifts in peak position and/or the changes in peak shape may be due to TO-LO splitting. Before one assigns the optical behavior to surface phenomena such as molecular orientation, proper care must be employed. The proposed technique includes optical calculation to extract surface phenomena from TO-LO splitting in the spectra, and it is applied to reflection absorption spectra of perfluoropolyether.
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10

Bobrysheva, A. I., and W. M. Shvera. "The Influence of the Excitonic Longitudinal-Transverse Splitting on the Biexciton Binding Energy." physica status solidi (b) 132, no. 2 (December 1, 1985): K107—K110. http://dx.doi.org/10.1002/pssb.2221320248.

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11

NOBARY, M. A. GOMSHI, and T. O'SATI. "FRAGMENTATION FUNCTIONS FOR Bc AND $B^*_c$ MESONS WITH DEFINITE POLARIZATION." Modern Physics Letters A 15, no. 07 (March 7, 2000): 455–64. http://dx.doi.org/10.1142/s021773230000044x.

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We present exact fragmentation functions for the production of S-wave Bc and [Formula: see text] mesons splitting out of a [Formula: see text]-antiquark. We distinguish transverse and longitudinal polarizations of [Formula: see text] which is important in hadronic spin properties of such states. Input parameters for our functions are quark masses, meson decay constants, and the transverse momentum for the hard production mechanism. Evolution of such functions from fragmentation scale up to an appropriate factorization scale are given. We compare our results with similar ones in the literature.
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12

Shan, Shu-Ping, Shi-Hua Chen, Ren-Zhong Zhuang, and Chun Hu. "Influence of magnetic field on the properties of polaron in an asymmetric quantum dot." International Journal of Modern Physics B 33, no. 23 (September 20, 2019): 1950263. http://dx.doi.org/10.1142/s0217979219502631.

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Influence of the magnetic field on the properties of the polaron in an asymmetric quantum dot is studied by using the Pekar variation method. The expression of the magnetopolaron ground-state energy is obtained by theoretical derivation. The relationship between the ground-state energy of the magnetopolaron with the transverse confinement strength, the longitudinal confinement strength and the magnetic field cyclotron resonance frequency are further discussed by us. Due to the crystal structure inversion asymmetry and the time inversion asymmetry, the polaron energy causes Rashba spin–orbit splitting and Zeeman splitting. Under the strong and weak magnetic fields, we discuss the dominant position of Rashba effect and Zeeman effect, respectively. Due to the presence of phonons, the polaron is more stable than the bare electron state, and the energy splitting is more stable.
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13

Durman, Ray, Upali A. Jayasooriya, and Sidney F. A. Kettle. "Is cerussite an aragonite? Longitudinal optical–transverse optical splitting in the single-crystal Raman spectra." J. Chem. Soc., Chem. Commun., no. 13 (1985): 916–17. http://dx.doi.org/10.1039/c39850000916.

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14

Nie, Yizhou, Niranjan D. Parab, Jou-Mei Chu, Garam Kim, Tao Sun, Kamel Fezzaa, Ronald Sterkenburg, and Weinong W. Chen. "Dynamic crack propagation from a circular defect in a unidirectional carbon fiber reinforced plastic composite." Journal of Composite Materials 52, no. 25 (September 3, 2018): 3539–47. http://dx.doi.org/10.1177/0021998318797394.

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A single-ply unidirectional IM7/8552 carbon fiber reinforced plastic composite with artificially introduced circular defects is subjected to dynamic tensile loading using a modified Kolsky tension bar. A high-speed X-ray phase contrast imaging method is integrated with the Kolsky bar setup to record the crack initiation from the defects and subsequent propagation in the material in real time during the tensile loading. The tensile loading was applied either in longitudinal (0° to fibers) or transverse (90° to fibers) direction of the specimens. Shear failure of the matrix and axial splitting along the loading/fiber direction were observed in longitudinal specimens to initiate from the edge of the artificial circular defects. Debonding of fiber and matrix was observed in transverse specimens, which initiated from the top and bottom edge of the hole. The dynamic tensile loading history during the crack propagation was recorded using a piezoelectric load cell and synchronized with the observed damage and failure processes.
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15

Kuo, Shou-Yi, Chung-Ting Li, and Wen-Feng Hsieh. "Decreasing giant splitting of longitudinal and transverse optical phonons in PbxSr1−xTiO3 due to Pb covalency." Applied Physics Letters 81, no. 16 (October 14, 2002): 3019–21. http://dx.doi.org/10.1063/1.1513660.

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16

Venger, E. F., A. V. Goncharenko, and S. N. Zavadskii. "Dielectric response of a crystal with a damaged surface layer in the longitudinal-transverse splitting region." Physics of the Solid State 43, no. 6 (June 2001): 1178–81. http://dx.doi.org/10.1134/1.1378163.

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17

Włoch, Wiesław, and Waldemar Szendera. "Observation of changes of cambial domain patterns on the basis of primary ray development in Fagus silvatica L." Acta Societatis Botanicorum Poloniae 61, no. 3-4 (2014): 319–30. http://dx.doi.org/10.5586/asbp.1992.028.

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The high multiseriate primary rays that occur in young stems of <i>Fagus silvatica</i> L. undergo splitting during cambium development. Segments of the split primary rays remain close to each other and form characteristic strands. Within these strands, sections can be observed in which the rays are split in the same direction, either in configuration Z or S. The configuration of other cambial cellular events neighboring the primary rays under consideration is in agreement with the configuration of the splitting of these rays. The arrangement of the rays on the surface of the wood after debarking a young stem makes it possible to decipher the domain pattern on a surface of any given size. As the stem segment ages, the borders between domains migrate and new borders are formed, changing their course from longitudinal to transverse.
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18

Hong, Lan, Jun Ge, Shan Shuang, and Da-Quan Liu. "Influence of Rashba effect and Zeeman effect on properties of bound magnetopolaron in an anisotropic quantum dot." Acta Physica Sinica 71, no. 1 (2022): 016301. http://dx.doi.org/10.7498/aps.71.20210803.

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The influence of Rashba effect and Zeeman effect on the properties of bound magnetopolaron in an anisotropic quantum dot are studied with Pekar variational method. The expression of the ground state energy of the bound magnetopolaron is obtained through theoretical derivation. The relationship of the ground state energy of the polaron with the transverse effective confinement length, the longitudinal effective confinement length, the magnetic field cyclotron resonance frequency, and the Coulomb bound potential are discussed, respectively. Owing to the crystal structural inversion asymmetry and the time inversion asymmetry, the polaron energy experiences Rashba spin-orbit splitting and Zeeman splitting. Under the strong and weak magnetic field, we discuss the dominant position of Zeeman effect and Rashba effect, respectively. Owing to the presence of phonons and impurities, the polaron is more stable than the bare electron state.
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19

Логинов, Д. К., and А. В. Донец. "Зависимость светоэкситонного взаимодействия от ширины квантовой ямы во внешнем однородном электрическом поле." Физика твердого тела 63, no. 4 (2021): 457. http://dx.doi.org/10.21883/ftt.2021.04.50709.238.

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The paper is devoted to analyse of the dependance of exciton-light coupling on a quantum well thickness at presence of an uniform electric field. It is shown that the increasing of quantum well thickness at an enough strong field results in decreasing of the exciton-light coupling in compare with narrower wells.The numerical calculations of longitudinal-transverse splitting are performed for a wide ranges of both electric field and values of quantum well thickness.The analyse of obtained data allows to get analytical expressions which desсribe the exciton-light coupling dependence like on the electric field as quantum well thickness.
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20

Ramakrishnan, Chellam, K. Navaneethakrishnan, and N. Krishnamurthy. "Effect of screening on the long-wavelength optical phonons in La1.85Sr0.15CuO4." Canadian Journal of Physics 70, no. 5 (May 1, 1992): 352–56. http://dx.doi.org/10.1139/p92-057.

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The lattice dynamics of La1.85Sr0.15CuO4 are studied with a rigid-ion model that takes into account the anisotropic screening of the Coulomb field by the charge carriers. The coupling coefficients for the screened potential are obtained using a generalized Ewald transformation that incorporates the Thomas–Fermi screening function. From the calculated phonons in the long-wavelength region it can be seen that the screening considerably reduces the longitudinal optical–transverse optical splitting of the polar modes. The nonpolar modes do not exhibit any changes in their behaviour with respect to that in the unscreened Coulomb potential.
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21

Логинов, Д. К., and А. В. Донец. "Зависимость светоэкситонного взаимодействия от ширины квантовой ямы во внешнем однородном электрическом поле." Физика твердого тела 63, no. 4 (2021): 457. http://dx.doi.org/10.21883/ftt.2021.04.50709.238.

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The paper is devoted to analyse of the dependance of exciton-light coupling on a quantum well thickness at presence of an uniform electric field. It is shown that the increasing of quantum well thickness at an enough strong field results in decreasing of the exciton-light coupling in compare with narrower wells.The numerical calculations of longitudinal-transverse splitting are performed for a wide ranges of both electric field and values of quantum well thickness.The analyse of obtained data allows to get analytical expressions which desсribe the exciton-light coupling dependence like on the electric field as quantum well thickness.
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22

Loginov, D. K., and A. V. Donets. "Dependence of the Longitudinal-Transverse Exciton Splitting in a Quantum Well on an External Homogeneous Electric Field." Physics of the Solid State 62, no. 2 (February 2020): 246–51. http://dx.doi.org/10.1134/s106378342002016x.

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23

Misochko, O. V., M. V. Lebedev, and T. Dekorsy. "Observation of longitudinal optical–transverse optical splitting for E-symmetry phonons in Te by coherent phonon spectroscopy." Journal of Physics: Condensed Matter 17, no. 19 (April 29, 2005): 3015–23. http://dx.doi.org/10.1088/0953-8984/17/19/015.

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24

Pincus, HJ, and HJ Pincus. "Round One—Longitudinal and Transverse Pulse Velocities, Unconfined Compressive Strength, Uniaxial Elastic Modulus, and Splitting Tensile Strength." Geotechnical Testing Journal 16, no. 1 (1993): 138. http://dx.doi.org/10.1520/gtj10279j.

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25

Durman, R., P. Favre, U. A. Jayasooriya, and S. F. A. Kettle. "Longitudinal optical-transverse optical (L.O.-T.O.) splitting on internal modes in the Raman spectra of noncentric crystals." Journal of Crystallographic and Spectroscopic Research 17, no. 4 (August 1987): 431–84. http://dx.doi.org/10.1007/bf01180320.

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26

Li, Zhi-Xin, Cheng-Hong Yin, and Xiu-Yun Zhu. "Influence of Rashba spin-orbit interaction and Zeeman splitting on the ground state energy of polaron in an asymmetric quantum dot." Modern Physics Letters B 29, no. 22 (August 20, 2015): 1550124. http://dx.doi.org/10.1142/s0217984915501249.

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On the basis of Lee–Low–Pines unitary transformation, the influence of Rashba spin-orbit (RSO) interaction and Zeeman splitting on the ground state energy of polaron in an asymmetric quantum dot (AQD) is studied by using the variational method of Pekar type. The variations of the absolute ratios of the Zeeman splitting energy and the RSO coupling energy to the ground state energy of polaron with the transverse confinement length (TCL) and the longitudinal confinement length (LCL) of AQD and the magnetic field adjusting length (MFAL) are derived when the RSO interaction and the Zeeman splitting are taken into account. We find the influences of the Zeeman splitting energy and the RSO coupling energy on the ground state energy of a polaron are more dominant when the values of the TCL and the LCL are small. The absolute ratio of the Zeeman splitting energy to the ground state energy rapidly decreases with increasing the MFAL and the absolute ratio of the RSO coupling energy to the ground state energy slowly decreases with increase in MFAL when [Formula: see text], whereas the absolute ratio of the RSO coupling energy to the ground state energy rapidly increases with increase in MFAL when [Formula: see text]. The above results can be attributed to the interesting quantum size confining and spin effects.
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27

Jones, Llewellyn H., and Basil I. Swanson. "Transverse optical to longitudinal optical splitting and dipole moment derivatives from infrared spectra of thin films of molecular solids." Journal of Physical Chemistry 95, no. 7 (April 1991): 2701–7. http://dx.doi.org/10.1021/j100160a016.

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28

Rowland, B., N. S. Kadagathur, and J. P. Devlin. "Infrared spectra of CF4 adsorbed on ice: Probing adsorbate dilution and phase separation with the ν3 transverse‐longitudinal splitting." Journal of Chemical Physics 102, no. 1 (January 1995): 13–19. http://dx.doi.org/10.1063/1.469384.

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29

Oguejiofor, E. C., and M. U. Hosain. "Tests of full-size composite beams with perfobond rib connectors." Canadian Journal of Civil Engineering 22, no. 1 (February 1, 1995): 80–92. http://dx.doi.org/10.1139/l95-008.

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This paper presents the test results of six full-size composite beam specimens with perfobond rib shear connectors embedded in solid concrete slab. The objective of this investigation was to study the performance of this connector in full-size composite beams and to correlate the test results with those obtained from push-out specimens. In the first three beam specimens, the amount of transverse reinforcement was varied. Two other specimens were used to investigate the effectiveness of more perfobond rib connectors of shorter length. The effect of passing transverse reinforcing bars through the connector rib holes was investigated using the last specimen. Failure of the test specimens was initiated by longitudinal splitting of the concrete slab, eventually culminating in the crushing of concrete in the bearing zone immediately in front of the end perfobond rib connectors. The test results showed that increasing the transverse reinforcement ratio, excluding the wire mesh, from 0.11% to 0.20% led to a 10% increase in the ultimate capacity. The test specimen with six 251 mm long connectors sustained 11% higher ultimate capacity compared to that with four 376 mm long connectors. An increase of 8.4% in the ultimate strength was observed when transverse reinforcing bars were passed through the perfobond rib holes while keeping the total amount of transverse reinforcement unchanged. The experimental values of the ultimate flexural capacity of the beam specimens were, on the average, approximately 1.11 times the predicted values based on push-out test results. Key words: composite beam, perfobond rib connector, push-out test, full-size test, flexural capacity.
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30

Ayas, Hillal, Mohamed Chabaat, and Lyes Amara. "Dynamic analysis of a cracked bar by the method of characteristics." International Journal of Structural Integrity 10, no. 4 (August 12, 2019): 438–53. http://dx.doi.org/10.1108/ijsi-01-2018-0001.

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Purpose The purpose of this paper is to introduce a new numerical approach for studying a cantilever bar having a transverse crack. The crack is modeled by an elastic longitudinal spring with a stiffness K according to Castiglione’s theorem. Design/methodology/approach The bar is excited by different longitudinal impulse forces. The considered problem based on the differential equation of motion is solved by the method of characteristics (MOC) after splitting the second-order motion equation into two first-order equivalent equations. Findings In this study, effects of the crack size and crack’s position on the reflected waves from the crack are investigated. The results indicate that the presence of the crack in the cantilever bar generates additional waves caused by the reflection of the incident wave by the crack. Originality/value A numerical approach developed in this paper is used for detecting the extent of the damage in cracked bars by the measurement of the difference between the dynamic response of an uncracked bar and a cracked bar.
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31

Mims, C. W., and E. A. Richardson. "Ultrastructure of sporodochium and conidium development in the anamorphic fungus Epicoccum nigrum." Canadian Journal of Botany 83, no. 10 (October 2005): 1354–63. http://dx.doi.org/10.1139/b05-137.

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Scanning and transmission electron microscopy were used to examine sporodochium and conidium development in Epicoccum nigrum Link. Each sporodochium, a slightly raised mass of hyphae consisting of a pseudoparenchymous stroma covered with muriform conidia, arose from a group of loosely packed hyphae that formed on the agar surface. Conidiophores developed from the surface of the stroma. Each possessed a two-layered wall consisting of an inner electron transparent layer and an outer electron dense layer. Most conidiophores consisted of only two cells, the apical of which became swollen and gave rise to a solitary conidium initial in a holoblastic fashion. This initial enlarged and became divided into a smaller basal cell and a larger apical cell by a transverse septum. While the basal cell did not divide further, the apical cell became divided into numerous cells as the result of the formation of longitudinal and transverse septa. As a conidium matured the electron transparent inner layer of its wall thickened while the surface of its electron dense outer wall layer became transformed into small wart-like surface ornaments. Conidium secession was schizolytic and involved a transverse splitting of the septum separating the basal cell of a conidium from its conidiophore. The end of the basal cell and the tip of the conidiophore became rounded off during conidium secession.
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32

Lawrence Watters, Conrad William, Carmen Jadick, and Phillipe Fleuriau-Chateau. "Anatomical Findings and Preservation of Transverse Sensory Branches of the Palmar Cutaneous Nerve during Carpal Tunnel Decompression." Canadian Journal of Plastic Surgery 5, no. 2 (May 1997): 123–26. http://dx.doi.org/10.1177/229255039700500201.

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Of the possible complications following carpal tunnel release, one of the most distressing to the patient is a painful surgical scar. In this clinical study, 89 hands were examined at the time of surgery in order to identify the precise location, number and size of transverse sensory branches of the median palmar cutaneous nerve (PCN) and to preserve these during the procedure. Without the aid of operating microscope or loupes, a longitudinal interthenar incision was made, followed by careful splitting dissection of the subcutaneous fat. Transverse branches of the PCN, arising from the median nerve, were found in 85.4% of hands. Both median and ulnar nerve branches were found in 3.4% of hands, only ulnar nerve branches were found in 1.12% of hands and no branches were identified in 13.5% of hands. Multiple branches were found in 32.6% of cases. On average, these branches crossed the palm 1.5 cm from the distal wrist crease and were preserved 95% of the time without the use of operating microscope or loupes. Preservation of these small sensory nerves may prevent neuroma formation and, thereby, reduce the incidence of painful scars following carpal tunnel release.
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33

CHO, KIKUO, KIYOHIKO KAWANO, TETSUYA TSUJI, and HIROSHI AJIKI. "OPTICAL RESPONSE OF A CONFINED EXCITON IN A SPHERE WITH THE EFFECTS OF LT SPLITTING AND BACKGROUND POLARIZATION: COMPARISON OF TWO DIFFERENT APPROACHES." International Journal of Modern Physics B 15, no. 28n30 (December 10, 2001): 3619–22. http://dx.doi.org/10.1142/s0217979201008287.

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The optical response spectra of a weakly confined exciton in a sphere, obtained via microscopic nonlocal response theory, have been compared with the macroscopic approach combined with Pekar type additional boundary condition (ABC). The results give a good agreement with respect to the peak positions and their intensities, indicating that the non-escape boundary condition for the exciton wave function is equivalent to Pekar type ABC. It is also stressed that the microscopic approach is much suitable to discussing the details of the quantized excitons, such as the character of transverse (T), longitudinal (L) and LT-mixed modes, and the radiative shift and width of each level, and the details of the internal field.
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34

Tofil, Arkadiusz, Janusz Tomczak, and Tomasz Bulzak. "Comparative Analysis of Forging Rolling and Cross-Wedge Rolling of Forgings from Titanium Alloy Ti6Al4V." Key Engineering Materials 687 (April 2016): 141–48. http://dx.doi.org/10.4028/www.scientific.net/kem.687.141.

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Theoretical-experimental results of forging rolling and cross-wedge rolling of stepped shafts forgings from titanium alloy Ti6Al4V are presented in this paper. Theoretical assumptions were based on the results of numerical simulations conducted by means of finite element method with the application of software Simufact Forming. During numerical simulations optimal parameters of the rolling processes were determined in view to possibility of obtaining forgings of assumed quality and stable process course. Experimental verification was conducted in universal forging rolling mill of own design, which allows for realization of such processes as splitting without waste, forging rolling and cross as well as cross-wedge rolling processes. During conducted research influence of the way of rolling on the obtained parts quality and the process force parameters were determined. Complex analysis of the chosen rolling parameters impact on the rolling process course and quality of finished products was made. Conducted research showed that it is possible to roll axi-symmetrical forgings of stepped shafts both in transverse and longitudinal arrangement. However, forgings rolled crosswise are characterized by larger precision than in comparison with semi-finished products in longitudinal arrangement.
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35

Rezansoff, T., U. S. Konkankar, and Y. C. Fu. "Confinement limits for tension lap slices under static loading." Canadian Journal of Civil Engineering 19, no. 3 (June 1, 1992): 447–53. http://dx.doi.org/10.1139/l92-054.

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In tension lap splices, the benefit provided to the lap by stirrups placed to intercept longitudinal cracking due to bond splitting action is recognized by the American Concrete Institute code (ACI 318-89) and the design recommendations of ACI Committee 408, on which the American code provisions are partially based. However, a limit exists on the benefit that can be derived from this confinement. In Canada, Canadian Standards Association Standard CAN3 A23.3 M-84 does not directly recognize the confinement benefit provided by stirrups placed along a lap splice. The current study shows that the ACI limit of 1 bar diameter of equivalent concrete cover provided by the transverse reinforcement confinement is too restrictive under static loading. When the concrete cover is small, much larger transverse reinforcement confinement, up to 2-2.5 bar diameters of equivalent concrete cover, can be utilized, in lieu of requiring very long lap lengths. The tests also show that total confinement (actual concrete confinement plus equivalent concrete confinement provided by stirrups) is effective beyond the current limit of 3 main bar diameters, when stirrups are provided. Good performance was found with confinements of 4-4.5 bar diameters, and correspondingly shorter lap splice lengths. Key words: concrete, reinforcement, lap splices, beams, confinement, stirrups, tension, static loading.
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36

Mazen, S. A., and T. A. Elmosalami. "Structural and Elastic Properties of Li-Ni Ferrite." ISRN Condensed Matter Physics 2011 (January 4, 2011): 1–9. http://dx.doi.org/10.5402/2011/820726.

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Li-Nickel ferrites with the chemical formula () have been prepared by the ceramic method. The spinel structure in homogenous state was realized by X-ray diffraction analysis. The lattice parameter has been determined for each composition and found to be nearly constant over the whole range of Ni concentration (= 0.83 nm ± 0.01). The cation distribution for each composition has been suggested. The experimental and theoretical lattice constants were found to be in good agreement with each other confirming the agreeability of the suggested cation distribution. The analysis of IR spectra indicates the presence of splitting in the absorption band due to the presence of small amounts of Fe2+ ions in the ferrite system. The force constants for tetrahedral and octahedral sites have been determined. Young’s modulus (E), rigidity modulus (G), bulk modulus (B), Debye temperature (), and transverse () and longitudinal () wave velocities have been determined. The variation of elastic moduli with composition has been interpreted in terms of binding forces between the atoms of spinal lattice.
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37

Ahmad, Javed, M. Qadeer Awan, Roomana Yasmin, Maria Sabir, Shafiq Anwar, M. Ehsan Mazhar, and Syed Hamad Bukhari. "Infrared reflectance spectroscopy of MgAl2O4 nanoparticles substituted by K+ ions." International Journal of Modern Physics B 32, no. 06 (February 26, 2018): 1850067. http://dx.doi.org/10.1142/s0217979218500674.

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The infrared reflectivity spectra for potassium-doped polycrystalline magnesium aluminates Mg[Formula: see text]K[Formula: see text]Al2O4 (x=0, 0.25, 0.50, 0.75, 1) are measured in the frequency range between 10–15, 500 cm[Formula: see text] using FTIR spectrometer at room-temperature. Four optical phonon modes are observed in measured spectra, which are fitted by Lorentz oscillator model for semiconducting behavior and Lorentz–Drude model for metallic behavior. Moreover, optical parameters are also determined for these modes which may attribute to spinel structure for samples Mg[Formula: see text]K[Formula: see text]Al2O4, their reflectivity spectra shows a typical semiconducting nature. To study ionicity and effect of polarization, Born and Szigeti effective charges are calculated from longitudinal optical and transverse optical (LO–TO) splitting of modes for all samples. Optical bandgap has been estimated through optical conductivity ([Formula: see text]([Formula: see text])) and found to be x dependent.
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38

Michaelian, K. H. "The Raman spectrum of kaolinite #9 at 21°C." Canadian Journal of Chemistry 64, no. 2 (February 1, 1986): 285–94. http://dx.doi.org/10.1139/v86-048.

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The Raman spectrum of kaolinite #9, a layer silicate of composition Al2Si2O5(OH)4 from Mesa Alta, New Mexico, USA, is reported and compared to previously published Raman and infrared spectra, as well as calculated lattice vibration frequencies, of other kaolinite samples. In the OH stretching region, a Raman band is observed at 3684 cm−1, a frequency which is generally unknown in infrared spectra of kaolinite. The two most likely origins of this band are (a) uncoupled inner-surface hydroxyl stretching, and (b) transverse/longitudinal splitting involving the 3695 cm−1 band, which occurs in both Raman and infrared spectra of kaolinite. The existing data do not conclusively show which of these explanations is correct. In the lattice vibration region, most of the observed Raman bands of kaolinite #9 have been tentatively assigned by comparison with published frequency calculations and existing assignments of infrared spectra of various kaolinites. The descriptions of many of the vibrational modes are approximate, partly because extensive mixing of vibrations makes a simple description of them impossible.
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39

Popov, Alexander L., and Sergey A. Sadovskiy. "Influence of beam butt face nonparallelism on free damped vibration spectrum of the beam." Vestnik MGSU, no. 5 (May 2019): 538–47. http://dx.doi.org/10.22227/1997-0935.2019.5.538-547.

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Introduction. The free vibration method is widely applied to detecting internal defects in rod and lamellar structural elements. In this work, it is used to diagnose a rod sample defect consisting in nonparallelism of the rod ends. The possibility of identifying a defect in the form of a bevel of one of the rod butts by the frequency spectrum of free damped longitudinal and transverse vibration after impact actions to the rod side or butt face is considered. Materials and methods. An experimental facility and a method of contact-free recording of the frequency spectrum of the rod natural vibration by its acoustic radiation spectrum are presented. Signs of a defect in the form of a split frequency of the rod transverse vibration are detected. At the same time, the maximum amplitudes of the split frequencies correspond to higher or lower frequencies depending on the face to which the impact is applied. This allows not only determining the presence of a defect in the form of the bevelled butt face, but also establishing its orientation relative to the side rod faces. Results. An approximate theoretical model is suggested. It explains the effect of frequency splitting in the presence of nonparallelism of the rod butts. For this, the frequency spectra of transverse vibration of two rods with lengths equal to the lengths of the smaller and the larger faces of the original rod with the bevel edge are considered. Experiments show that the differences in the natural frequencies of the bending vibration of these rods, which correspond to the same eigenmodes, are consistent with the differences in the split frequencies of the free damped transverse vibrations of the bevelled-face rod. At this, relationship between the split frequency amplitudes allows determining not only the presence of bevelled face, but also its location. Conclusions. The application and development of the method through the analysis of the natural vibration spectrum can lead to creation of remote quality control equipment for rod structural elements.
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40

Gil Sevillano, J., D. González, and J. M. Martínez-Esnaola. "Heterogeneous Deformation and Internal Stresses Developed in BCC Wires by Axisymmetric Elongation." Materials Science Forum 550 (July 2007): 75–84. http://dx.doi.org/10.4028/www.scientific.net/msf.550.75.

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BCC wires macroscopically deformed by axisymmetric elongation (wire drawing) develop an intense <011> fibre texture and exhibit a characteristic non-uniform deformation of the grains evident in transverse sections (grain curling or “Van Gogh sky structure”). The extraordinary grain morphology induced by the <011> fibre texture is also accompanied by a peculiar constant strain hardening rate in single-phase BCC wires (exponentially increasing in case of BCC containing composite wires) that allows to reach very high strengths. Here we present a calculation of the elastoplastic axial elongation of such an aggregate of BCC grains with the ideal <011> fibre texture, using a slip-gradient dependent large-strain crystal plasticity constitutive equation incorporated into a finite element method (FEM) code, i.e., with proper account of the influence of the evolving shape and size of individual grains and of the local grain interactions. The results reproduce well the observed macroscopic behaviour (linear flow stress-strain curve at large strains) and the peculiar mesoscopic structural changes (grain curling in transverse sections). The simulation is focused on the analysis of strain and dislocation density heterogeneities and on the building up of mesoscopic (inter- and intra-granular) internal stresses during deformation. The computed average transverse tensile stresses acting normal to the axially oriented {100} planes approximately parallel to the boundaries of the flattened grains is close to 0.3 times the tensile flow stress of the aggregate, in good agreement with previous calculations based on the Taylor-Bishop-Hill model or on elasticplastic self-consistent calculations and with available neutron diffraction measurements. Such a high level of internal tensile stresses explains the well-known tendency of high strength BCC wires to fail by longitudinal splitting.
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41

Tsuneda, A., N. Maekawa, I. Ohira, and I. Furukawa. "Incipient decay of Quercus serrata sapwood by Lentinus edodes and its inhibition by an antagonistic hyphomycete, Leptodontidium elatius." Canadian Journal of Botany 69, no. 12 (December 1, 1991): 2797–805. http://dx.doi.org/10.1139/b91-350.

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Incipient decay of Quercus serrata by Lentinus edodes and its inhibition by Leptodontidium elatius were investigated by scanning electron microscopy. Rapid accumulation of L. edodes hyphae in earlywood vessels was a prerequisite to efficient decay of sapwood. In the early stages of decay, selective removal of lignin and other amorphous wall components occurred in the vessels and surrounding tissues, including vasicentric tracheids and wood fibres. Thus, bundles of cellulose microfibrils, having lateral dimensions of 15–50 nm, became recognizable. Disintegration of cellulose microfibril bundles appeared to begin with longitudinal and (or) transverse splitting of the bundles, and then the walls became progressively thinner. In ray parenchyma cells, end walls were susceptible to the fungal degradation, but lateral walls, particularly the innermost layer, were relatively resistant. Hyphae of L. elatius grew in close contact with the vessel wall and exuded slime material to create a distinct microarea (mycosphere) around them. In the vessels precolonized by this hyphomycete, the growth rate of L. edodes hyphae was drastically reduced to less than 20% of that in antagonist-free vessels. Possible roles of the slime material in this antagonism are discussed. Key words: wood decay, Lentinus edodes, Leptodontidium elatius, antagonism, mycosphere.
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42

Bini, Donato, Paolo Carini, and Robert T. Jantzen. "The Intrinsic Derivative and Centrifugal Forces in General Relativity: I." International Journal of Modern Physics D 06, no. 01 (February 1997): 1–38. http://dx.doi.org/10.1142/s0218271897000029.

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Everyday experience with centrifugal forces has always guided thinking on the close relationship between gravitational forces and accelerated systems of reference. Once spatial gravitational forces and accelerations are introduced into general relativity through a splitting of spacetime into space-plus-time associated with a family of test observers, one may further split the local rest space of those observers with respect to the direction of relative motion of a test particle world line in order to define longitudinal and transverse accelerations as well. The intrinsic covariant derivative (induced connection) along such a world line is the appropriate mathematical tool to analyze this problem, and by modifying this operator to correspond to the observer measurements, one understands more clearly the work of Abramowicz et al. who derine an "optical centrifugal force" in static axisymmetric spacetimes and attempt to generalize it and other inertial forces to arbitrary spacetimes. In a companion article the application of this framework to some familiar stationary axisymmetric spacetimes helps give a more intuitive picture of their rotational features including spin precession effects, and puts related work of de Felice and others on circular orbits in black hole spacetimes into a more general context.
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43

Ivantsov, Andrey, Maria Zakrevskaya, Aleksey Nagovitsyn, Anna Krasnova, Ilya Bobrovskiy, and Ekaterina Luzhnaya (Serezhnikova). "Intravital damage to the body of Dickinsonia (Metazoa of the late Ediacaran)." Journal of Paleontology 94, no. 6 (September 2, 2020): 1019–33. http://dx.doi.org/10.1017/jpa.2020.65.

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AbstractSeveral specimens of Dickinsonia cf. D. menneri, originating from a single burial event at the Lyamtsa locality of the late Ediacaran (Vendian) in the southeastern White Sea area, Russia, represent deviations from normal morphology: a reduction in the total length of the body; the loss of portions of the body; various deformations of the transverse elements, called isomers; and splitting of the longitudinal axis with the formation of two posterior ends. It is assumed that these deformations were formed as a result of non-lethal damage, which occurred long before the burial event, and the response of Dickinsonia to them. The progress of the regeneration process at the damaged areas, and especially its deviations, indicates that the growth zone was located at the posterior end of the Dickinsonia body. The cause of non-lethal damage to Dickinsonia could not be established, but the local distribution of deformed specimens preserved in the same burial event alongside cyanobacterial colonies, and the presence of weak deformations, expressed only in shortening of the length of some isomers, lead to the conclusion that damage resulted from short episodes of physicochemical impact, rather than occasional attacks by a hypothetical macrophage.
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44

Talwar, Devki N., and Hao-Hsiung Lin. "Assessing thermodynamical properties of Al1−xGaxSb alloys and optical modes for Al1−xGaxSb/GaAs epifilms and (AlSb)m/(GaSb)n superlattices." Journal of Vacuum Science & Technology A 40, no. 3 (May 2022): 032801. http://dx.doi.org/10.1116/6.0001611.

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A generalized Green's function (GF) theory is adopted in the framework of a realistic rigid-ion-model (RIM) to assess the composition, x-dependent lattice dynamics, and thermodynamical characteristics of ideal random Al1−xGaxSb alloys. For simulating phonons, the alloy parameters are achieved by interpolating the values of the RIM force constants between AlSb and GaSb without requiring any additional interactions. The outcomes of phonon dispersions [Formula: see text], Debye temperature ΘD(T), and specific heat Cv(T) compare favorably well with the existing experimental and theoretical data. An established methodology of multilayer optics is also employed for modeling the far-infrared reflectance and transmission spectra of ultrathin GaSb/GaAs, AlSb/GaAs, Al1−xGaxSb/GaAs epilayers, and (AlSb)m/(GaSb)n/GaAs superlattices at near normal (θi = 0) incidence and oblique (θi ≠ 0) incidence. An accurate appraisal of the x-dependent longitudinal-optical [[Formula: see text]] and transverse-optical [[Formula: see text]] phonon splitting by Berreman's effect, along with the calculated GF results of localized vibrational mode ( GaSb:Al) and gap mode ( AlSb:Ga), is carefully integrated into the modified-random-iso-displacement model to validate the two-phonon mode behavior in Al1−xGaxSb ternary alloys.
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45

Deaton, Joseph C., Matthew S. Gebhard, and Edward I. Solomon. "Transverse and longitudinal Zeeman effect on [tetraphenylphosphonium tetrachloroferrate(1-)]: assignment of the ligand field transitions and the origin of the 6A1 ground-state zero-field splitting." Inorganic Chemistry 28, no. 5 (March 1989): 877–89. http://dx.doi.org/10.1021/ic00304a016.

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46

Polilov, A. N., D. D. Vlasov, and N. A. Tatus’. "Developing of the optimal shape and reinforcement structure of the specimen for adequate determination of the tensile strength in unidirectional composites." Industrial laboratory. Diagnostics of materials 87, no. 2 (February 16, 2021): 43–55. http://dx.doi.org/10.26896/1028-6861-2021-87-2-43-55.

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Unidirectional composites exhibit the highest strength when stretched along the fibers. However, the proper determination of the strength faces great methodological difficulties. The main problems of tensile testing of polymer composites consisted in developing of the specimen shape and the method of specimen fixation which ensure the minimum impact of the stress concentration near the grips on the strength measurements. A conventional shape of the specimen with fillets is unsuitable for unidirectional polymers due to the splitting occurred in the fillet zones upon loading. Therefore, the specimens are usually standardized in the form of rectangular strips fixed using pads or special grips which provide constant transverse forces. However, with such a specimen shape, a significant stress concentration inevitably occurs at the edge of grips and the lower the ratio of the interlayer shear modulus to the longitudinal Young’s modulus, the greater the stress concentration impact. For the purpose of the most correct determination of the strength we propose to use specimens with smoothly varying dimensions at the same cross-sectional area which ensures keeping the total number of unbroken fibers in each section. The specimen thickness decreases when moving from the working part of the specimen to the gripping part, whereas the width (while maintaining the section area) grows to prevent the specimen collapsing resulting from transverse forces in standard self-tightening grips. Analytical and FEM modeling is performed to select a rational contour shape. Technological equipment has been developed and a procedure of manufacturing testing specimens has been worked out. The tensile test of specially manufactured curvilinear reinforced specimens showed higher strength values compared to standard rectangular strips or specimens with semicircular fillets.
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47

Yang, Jianhui, Qiang Fan, You Yu, and Weibin Zhang. "Pressure Effect of the Vibrational and Thermodynamic Properties of Chalcopyrite-Type Compound AgGaS2: A First-Principles Investigation." Materials 11, no. 12 (November 26, 2018): 2370. http://dx.doi.org/10.3390/ma11122370.

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To explore the structural, vibrational, and thermodynamic properties of the chalcopyrite-type compound AgGaS2 under pressure, we applied hydrostatic pressure to the relaxed compound based on the first principles calculation and quasi-harmonic approximation. The structural parameters, including lattice constants and bond lengths decrease monotonically with the increasing pressure. The phonon dispersion curves under various pressures reveal the structural phase transition of chalcopyrite-type compound AgGaS2 at about 4 GPa. The intrinsic mechanism of thermal conductivity for the chalcopyrite-type compound AgGaS2 has been shown with phonon anharmonicity. The frequencies of the optical phonons at the center point Γ of the first Brillouin zone were calculated with the longitudinal optical–transverse optical (LO–TO) splitting mode. The dependence of the frequencies of the optical phonons on the pressure provides the information for the Raman spectroscopic study under high pressure. The pressure dependence of the Grüneisen parameters indicates that the instability of chalcopyrite-type compound AgGaS2 is associated with the softening of the acoustic phonon modes at around the center point Γ. The thermal conductivity for chalcopyrite-type compound AgGaS2 could be reduced by applying external pressure. The various thermodynamic properties, such as the Helmholtz free energy, entropy, and heat capacity, at different temperatures and pressures were discussed and analyzed based on the phonon properties.
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48

Bouhassoune, Mohammed, and Arno Schindlmayr. "Ab InitioStudy of Strain Effects on the Quasiparticle Bands and Effective Masses in Silicon." Advances in Condensed Matter Physics 2015 (2015): 1–8. http://dx.doi.org/10.1155/2015/453125.

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Usingab initiocomputational methods, we study the structural and electronic properties of strained silicon, which has emerged as a promising technology to improve the performance of silicon-based metal-oxide-semiconductor field-effect transistors. In particular, higher electron mobilities are observed inn-doped samples with monoclinic strain along the [110] direction, and experimental evidence relates this to changes in the effective mass as well as the scattering rates. To assess the relative importance of these two factors, we combine density-functional theory in the local-density approximation with theGWapproximation for the electronic self-energy and investigate the effect of uniaxial and biaxial strains along the [110] direction on the structural and electronic properties of Si. Longitudinal and transverse components of the electron effective mass as a function of the strain are derived from fits to the quasiparticle band structure and a diagonalization of the full effective-mass tensor. The changes in the effective masses and the energy splitting of the conduction-band valleys for uniaxial and biaxial strains as well as their impact on the electron mobility are analyzed. The self-energy corrections withinGWlead to band gaps in excellent agreement with experimental measurements and slightly larger effective masses than in the local-density approximation.
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49

Liu, Xiaochun, Zhiwu Yu, Ping Xiang, and Cheng Jin. "Composite action of the track slab and the self-compacting concrete filling layer subjected to train-induced fatigue load: An experimental investigation." Proceedings of the Institution of Mechanical Engineers, Part F: Journal of Rail and Rapid Transit 233, no. 5 (October 9, 2018): 580–92. http://dx.doi.org/10.1177/0954409718803821.

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To investigate the composite performance of the track slab and the self-compacting concrete filling layer in the China Railway Track System III slab track structure, six segmental specimens comprising either one or a pair of sleepers were fabricated by dividing a full-scale slab track structure. Fatigue tests in the transverse bending perpendicular to the rail were conducted on four slab track specimens supported on rubber plates simulating the subgrade, to a maximum of five million applied load cycles. It was observed in the fatigue tests that longitudinal cracks first appeared on the top surface of the track slab at the mid-span of the specimen. Splitting cracks appeared later from the anchorage ends of the transverse prestressed tendons to the top surface of track slab. Delamination of the track slab–filling layer interface developed with increasing number of cycles. Static three-point bending tests were also conducted on both fatigue-damaged and control composite plate specimens to evaluate the effect of fatigue damage on the composite performance of the track slab and the filling layer. In the static tests, significant deformation developed in the fatigue-damaged specimens from the start of loading, and the fatigue damage and interface delamination adversely affected the composite action of the track slab and the filling layer. Static loads corresponding to new cracking of the fatigue-damaged composite plates were reduced by 20–30%, and the load corresponding to the initial interlayer slip reduced by 25–62% compared with the control specimens. The interfacial bond strength between the track slab and the filling layer is the first line of defense against the interlayer slip, and the dowel action of the interlayer connection reinforcement is the second line of defense. Roughening by multitooth chiseling on the track slab and an increase in the ratio of interlayer connection reinforcements are both effective ways to enhance the composite action of the track slab and the filling layer.
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50

Taylor, David, and Jan-Henning Dirks. "Shape optimization in exoskeletons and endoskeletons: a biomechanics analysis." Journal of The Royal Society Interface 9, no. 77 (September 12, 2012): 3480–89. http://dx.doi.org/10.1098/rsif.2012.0567.

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This paper addresses the question of strength and mechanical failure in exoskeletons and endoskeletons. We developed a new, more sophisticated model to predict failure in bones and other limb segments, modelled as hollow tubes of radius r and thickness t . Five failure modes were considered: transverse fracture; buckling (of three different kinds) and longitudinal splitting. We also considered interactions between failure modes. We tested the hypothesis that evolutionary adaptation tends towards an optimum value of r/t , this being the value which gives the highest strength (i.e. load-carrying capacity) for a given weight. We analysed two examples of arthropod exoskeletons: the crab merus and the locust tibia, using data from the literature and estimating the stresses during typical activities. In both cases, the optimum r/t value for bending was found to be different from that for axial compression. We found that the crab merus experiences similar levels of bending and compression in vivo and that its r/t value represents an ideal compromise to resist these two types of loading. The locust tibia, however, is loaded almost exclusively in bending and was found to be optimized for this loading mode. Vertebrate long bones were found to be far from optimal, having much lower r/t values than predicted, and in this respect our conclusions differ from those of previous workers. We conclude that our theoretical model, though it has some limitations, is useful for investigating evolutionary development of skeletal form in exoskeletons and endoskeletons.
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