Artículos de revistas: "Double stretching"

1

Patterson, Richard F. "Analogues of some Tauberian theorems for stretchings". International Journal of Mathematics and Mathematical Sciences 27, n.º 2 (2001): 99–109. http://dx.doi.org/10.1155/s0161171201003933.

Texto completo

Resumen

We investigate the effect of four-dimensional matrix transformation on new classes of double sequences. Stretchings of a double sequence is defined, and this definition is used to present a four-dimensional analogue of D. Dawson's copy theorem for stretching of a double sequence. In addition, the multidimensional analogue of D. Dawson's copy theorem is used to characterize convergent double sequences using stretchings.

Los estilos APA, Harvard, Vancouver, ISO, etc.

2

Mathew-Fenn, Rebecca S., Rhiju Das, Timothy D. Fenn, Michael Schneiders y Pehr A. B. Harbury. "Response to Comment on “Remeasuring the Double Helix”". Science 325, n.º 5940 (30 de julio de 2009): 538.3–538. http://dx.doi.org/10.1126/science.1168876.

Texto completo

Resumen

We measured the mean and variance of end-to-end length in short DNA fragments in solution and reported evidence of DNA stretching that is cooperative over more than two turns of the double helix. Becker and Everaers suggest that the structural fluctuations we observed arise from bending motions of the DNA, rather than stretching. We present three experimental tests of this bending-based explanation.

Los estilos APA, Harvard, Vancouver, ISO, etc.

3

Hennig, D. y J. F. R. Archilla. "Stretching and relaxation dynamics in double stranded DNA". Physica A: Statistical Mechanics and its Applications 331, n.º 3-4 (enero de 2004): 579–601. http://dx.doi.org/10.1016/j.physa.2003.09.053.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

4

Scurtu, Adrian, Dorina Ticoș, Maria Luiza Mitu, Nicoleta Udrea y Cătălin Mihai Ticoș. "Stretching and Compression of Double Dusty Plasma Vortex". Crystals 13, n.º 1 (1 de enero de 2023): 76. http://dx.doi.org/10.3390/cryst13010076.

Texto completo

Resumen

The interest in complex plasmas is increasing due to the multiple applications they target (astrophysics, plasma fusion, industry, etc.). A crystal with two vortexes made of spherical microparticles that levitates in an rf plasma interacts with a gas jet. The crystal is displaced in the jet propagation direction due to the neutral pushing force, maintaining its vortex structure. The crystal shift also involves a change of its shape, especially at the level of the two vortexes. One vortex is stretched, and the other one is compressed. During the three phases of modification of the shape of the crystal, its length is approximately constant, about 12.5 mm, this being a consequence of the fact that electric forces and ion drag forces are preserved. The orderly structure of the crystal lasts until the particles begin to fall on the bottom electrode. The changing of the vorticity in the crystal regions can be attributed to the neutral push force.

Los estilos APA, Harvard, Vancouver, ISO, etc.

5

Becker, Nils B. y Ralf Everaers. "Comment on “Remeasuring the Double Helix”". Science 325, n.º 5940 (30 de julio de 2009): 538.2–538. http://dx.doi.org/10.1126/science.1168786.

Texto completo

Resumen

Mathew-Fenn et al. (Reports, 17 October 2008, p. 446) reported unexpected distance fluctuations in short end-labeled DNA constructs and interpreted them as evidence for cooperative DNA stretching modes. We show that when accounting for a subtle linker leverage effect, their data can be understood within standard noncooperative DNA elasticity.

Los estilos APA, Harvard, Vancouver, ISO, etc.

6

Rajalaxmi, V., S. Vasanthi, S. Sathya, K. Kirupa, SM Divya Mary, Vani Aravind y N. Muthukumaran. "Efficacy of Dynamic VS Closed Kinematic Exercise Combined with Stretching in Adhesive Capsulitis- a double blinded randomized controlled trial". Bangladesh Journal of Medical Science 20, n.º 2 (1 de febrero de 2021): 368–73. http://dx.doi.org/10.3329/bjms.v20i2.51550.

Texto completo

Resumen

Objective: To compare the efficacy of Dynamic exercise and Closed kinematic exercise combined with stretching in adhesive capsulitis. Background of the study: Adhesive capsulitis is a condition characterized by stiffness and pain in the shoulder joint. It is a painful and disabling disorder of unclear cause in which the shoulder capsule, the connective tissue surrounding the shoulder becomes inflamed and stiff, restricting ROM and causing chronic pain. Methodology: This was an experimental study design with Pre-Post test. 30 samples were selected from 45 volunteers based on the inclusion criteria. Group A-Dynamic exercise with stretching, Group B-Closed kinematic exercise with stretching, SWD is commonly given to the patients for 1 week. Results: The result concludes both the groups showed improvement while group A received Dynamic exercise with stretching was comparatively better than the Group B received Closed kinematic exercise with stretching Bangladesh Journal of Medical Science Vol.20(2) 2021 p.368-373

Los estilos APA, Harvard, Vancouver, ISO, etc.

7

Marin-Gonzalez, Alberto, J. G. Vilhena, Ruben Perez y Fernando Moreno-Herrero. "Understanding the mechanical response of double-stranded DNA and RNA under constant stretching forces using all-atom molecular dynamics". Proceedings of the National Academy of Sciences 114, n.º 27 (20 de junio de 2017): 7049–54. http://dx.doi.org/10.1073/pnas.1705642114.

Texto completo

Resumen

Multiple biological processes involve the stretching of nucleic acids (NAs). Stretching forces induce local changes in the molecule structure, inhibiting or promoting the binding of proteins, which ultimately affects their functionality. Understanding how a force induces changes in the structure of NAs at the atomic level is a challenge. Here, we use all-atom, microsecond-long molecular dynamics to simulate the structure of dsDNA and dsRNA subjected to stretching forces up to 20 pN. We determine all of the elastic constants of dsDNA and dsRNA and provide an explanation for three striking differences in the mechanical response of these two molecules: the threefold softer stretching constant obtained for dsRNA, the opposite twist-stretch coupling, and its nontrivial force dependence. The lower dsRNA stretching resistance is linked to its more open structure, whereas the opposite twist-stretch coupling of both molecules is due to the very different evolution of molecules’ interstrand distance with the stretching force. A reduction of this distance leads to overwinding in dsDNA. In contrast, dsRNA is not able to reduce its interstrand distance and can only elongate by unwinding. Interstrand distance is directly correlated with the slide base-pair parameter and its different behavior in dsDNA and dsRNA traced down to changes in the sugar pucker angle of these NAs.

Los estilos APA, Harvard, Vancouver, ISO, etc.

8

Zhou, Chengbo, Huilong Guo, Jingqing Li, Shaoyong Huang, Hongfei Li, Yanfeng Meng, Donghong Yu, Jesper de Claville Christiansen y Shichun Jiang. "Temperature dependence of poly(lactic acid) mechanical properties". RSC Advances 6, n.º 114 (2016): 113762–72. http://dx.doi.org/10.1039/c6ra23610c.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

9

Liu, S., D. Baugh, K. Motobayashi, X. Zhao, S. V. Levchenko, S. Gawinkowski, J. Waluk, L. Grill, M. Persson y T. Kumagai. "Anharmonicity in a double hydrogen transfer reaction studied in a single porphycene molecule on a Cu(110) surface". Physical Chemistry Chemical Physics 20, n.º 17 (2018): 12112–19. http://dx.doi.org/10.1039/c8cp00178b.

Texto completo

Resumen

A pronounced anharmonicity of the N–H stretching mode in porphycene on Cu(110) is observed in the STM action and conductance spectra. DFT calculations find a strong intermode coupling of the N–H stretching with an in-plane bending mode within porphycene on the surface.

Los estilos APA, Harvard, Vancouver, ISO, etc.

10

Sastry, M. I. S. y Surjit Singh. "Raman spectral studies of solutions of alkali metal perchlorates in dimethyl sulfoxide and water". Canadian Journal of Chemistry 63, n.º 7 (1 de julio de 1985): 1351–56. http://dx.doi.org/10.1139/v85-231.

Texto completo

Resumen

Raman spectra of solutions of alkali metal perchlorates in dimethyl sulfoxide (DMSO) in the Cl—O, C—S, and S=O stretching regions, as well as of perchlorates in aqueous solutions in the Cl—O stretching region are reported. The results are discussed in terms of half-bandwidths, relative intensities, and depolarization ratios. For H2O the half-bandwidth of the Cl—O stretching band at ~935 cm−1 is almost double the value in DMSO solutions. Solutions of perchlorates in DMSO show two symmetric bands in the Cl—O stretching region, whereas in aqueous solutions only one band is observed. The half-bandwidths in perchlorate solutions in DMSO for the C—S stretching band increase with increase in concentration of perchlorate compared to that of liquid DMSO. The band contours in the S=O stretching region in DMSO solutions also show significant changes. These observations are explained on the basis of formation of ion pairs of metal perchlorates in solutions of DMSO and ion hydrates in the case of aqueous solutions.

Los estilos APA, Harvard, Vancouver, ISO, etc.

11

Wang, Deqiang, Winston Timp, Ji Wook Shim, Utkur Mirsaidov, Jeff Comer, Aleksei Aksimentiev y Gregory Timp. "Discriminating Bases by Stretching Double-Stranded DNA in a Nanopore". Biophysical Journal 98, n.º 3 (enero de 2010): 599a. http://dx.doi.org/10.1016/j.bpj.2009.12.3259.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

12

Akbar, Noreen, z. Khan, S. Nadeem y W. khan. "Double-diffusive natural convective boundary-layer flow of a nanofluid over a stretching sheet with magnetic field". International Journal of Numerical Methods for Heat & Fluid Flow 26, n.º 1 (4 de enero de 2016): 108–21. http://dx.doi.org/10.1108/hff-01-2015-0019.

Texto completo

Resumen

Purpose – The purpose of this paper, is to study the MHD double-diffusive natural convection of a nanofluid over a linearly stretching sheet using the Buongiorno model. Design/methodology/approach – The transport equations are transformed into coupled similarity equations. The numerical self-similar solutions are compared with the literature for the special case of pure fluid flow and found to be in good agreement. Graphical results are presented to illustrate the effects of various fluid flow, heat transfer and nano concentration parameters for both assisting and opposing flows. Findings – It is found that the heat transfer rate increases as nanoparticles and salt are suspended in water. It is also found that dual solutions exist for the stretching parameter. Originality/value – First paper on this model for stretching sheet.

Los estilos APA, Harvard, Vancouver, ISO, etc.

13

Penderghest, Caroline E., Iris F. Kimura y Dawn T. Gulick. "Double-Blind Clinical Efficacy Study of Pulsed Phonophoresis on Perceived Pain Associated with Symptomatic Tendinitis". Journal of Sport Rehabilitation 7, n.º 1 (febrero de 1998): 9–19. http://dx.doi.org/10.1123/jsr.7.1.9.

Texto completo

Resumen

The purpose of this study was to determine the clinical efficacy of dexametha-sone-lidocaine (DX-L) phonophoresis on perceived pain associated with symptomatic tendinitis. Twenty-four subjects were randomly assigned to a DX-L or placebo phoresis group. All subjects received strengthening, stretching, and cryotherapy. Five double-blind sessions were administered over a 5- to 10-day period, with 24 to 48 hr between sessions. Perceived pain was quantified using a visual perceived pain scale (VPPS) and a punctate tenderness gauge (PTG). Data were collected before stretching, strengthening, and DX-L/placebo phoresis treatments, 1 min after treatment, and 10 min after cryotherapy. There were no significant differences for VPPS or PTG between groups. There was a significant difference between treatment sessions, regardless of group or test, and there were significant decreases in perceived pain between Tests 1 and 3 and between Treatment Sessions 1 and 5. It was concluded that stretching, strengthening, and cryotherapy significantly decreased the levels of perceived pain associated with symptomatic tendinitis regardless of whether the subjects received phonophoresis.

Los estilos APA, Harvard, Vancouver, ISO, etc.

14

Kutsenko, O. G., A. G. Kutsenko y L. V. Kharytonova. "Study of perforated plates stretching by finite element method". Bulletin of Taras Shevchenko National University of Kyiv. Series: Physics and Mathematics, n.º 3 (2021): 55–58. http://dx.doi.org/10.17721/1812-5409.2021/3.8.

Texto completo

Resumen

The problem of axial stretching of a plate with a double-periodic system of round holes arranged in a checkerboard pattern is considered. The specified problem is reduced to elasticity second problem for one period of plate, which was solved by the finite element method. As a result, the reduced elastic characteristics of the equivalent homogeneous orthotropic plate are found. The analysis of their behavior depending on dimensionless geometrical parameters is carried out. The area of variation of the geometric parameters was divided into two subareas. The behavior of the equivalent elastic characteristics in these areas is significantly different. It turned out that the double-periodic perforated plate shows significantly anisotropic behavior. The limit values of the Poisson's ratios can reach unity and, on the other hand, may be less than the original value. Dependences of the stress concentration coefficient on dimensionless geometrical parameters are obtained too. Performed comparative analysis of the obtained results with the results known from the literature, confirmed their adequacy.

Los estilos APA, Harvard, Vancouver, ISO, etc.

15

Lim, Chi-Su, Dae-Sung Jang, Sang-Min Yu y Jae-Jun Lee. "Analysis of the Properties of Modified Asphalt Binder by FTIR Method". Materials 15, n.º 16 (19 de agosto de 2022): 5743. http://dx.doi.org/10.3390/ma15165743.

Texto completo

Resumen

The usage of modified asphalt binder in road pavements has been increasing in the past few decades. Therefore, quality control and understanding of modified asphalt binders have become an important issue. This study was conducted as a part of a larger study on the efficient management of these modified asphalt binders by evaluating the characteristics of asphalt binders mixed with styrene–butadiene–styrene (SBS), ethylene-vinyl acetate (EVA), and wax-based warm-mix additives using Fourier transform infrared (FTIR) analysis. For original asphalt binders modified with SBS, response wavenumbers were 700 and 966 cm−1, which means a particular wavenumber of polybutadiene and polystyrene, while in the case of binders modified with EVA, peak response wavenumbers were at 1242 and 1739 cm−1, which represents a particular wavenumbers of a single stretching bond between carbon and hydrate and a double stretching bond between carbon and oxygen. Asphalt binders modified with wax-type additives showed peak response at 730 and 1540 cm−1, which represents a double stretching bond of carbon and a single stretching bond between nitrogen and oxygen. It was also found that peak values increased as addition rates also increased. The results showed that the additives used in this study have particular wavenumbers that show peak responses even when mixed into asphalt binders. Using these characteristics of the additives, FTIR analysis confirms that it is possible to determine whether or not a binder has been modified.

Los estilos APA, Harvard, Vancouver, ISO, etc.

16

Kamble, Harshad, Raja Vadivelu, Mathew Barton, Kseniia Boriachek, Ahmed Munaz, Sungsu Park, Muhammad Shiddiky y Nam-Trung Nguyen. "An Electromagnetically Actuated Double-Sided Cell-Stretching Device for Mechanobiology Research". Micromachines 8, n.º 8 (22 de agosto de 2017): 256. http://dx.doi.org/10.3390/mi8080256.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

17

Lee, Seung-Woong y Jung-Hoon Lee. "Effects of Proprioceptive Neuromuscular Facilitation Stretching and Kinesiology Taping on Pelvic Compensation During Double-Knee Extension". Journal of Human Kinetics 49, n.º 1 (1 de diciembre de 2015): 55–64. http://dx.doi.org/10.1515/hukin-2015-0108.

Texto completo

Resumen

Abstract Shortened hamstrings are likely to restrict the anterior pelvic tilt and induce a slumped posture due to the posterior pelvic tilt. This study was conducted to compare the effects of proprioceptive neuromuscular facilitation (PNF) stretching and modified anterior pelvic tilt taping (APTT) on hamstring shortness-associated pelvic compensation while executing seated double-knee extension. Male college students (28 healthy young adults; mean age: 21.4 ± 2.1 years) with hamstring shortness were recruited as study subjects and randomly assigned to either the PNF stretching group (control group) or the APTT group (experimental group). In all the subjects, changes in the movement distance of the centre of gluteal pressure (COGP) as well as rectus abdominis (RA) and semitendinosus (SEM) muscle activities were measured during seated double-knee extension while the respective intervention method was applied. Both groups showed significant decreases in COGP distance and RA muscle activity compared with their respective baseline values (p < 0.05), however, no significant changes were observed in SEM muscle activity. We can infer that not only a direct intervention on the hamstring, such as PNF stretching, but also a modified APTT-mediated pelvic intervention may be used as a method for reducing pelvic compensation induced by hamstring shortness.

Los estilos APA, Harvard, Vancouver, ISO, etc.

18

Osman, Mohd Junaedy, Wan Md Zin Wan Yunus, Keat Khim Ong, Noor Azilah Mohd Kasim, Siti Hasnawati Jamal, Mansor Ahmad y Nor Azowa Ibrahim. "Surface Modification of Multi-Walled Carbon Nanotube Using Double-Chained Quartenary Ammonium Bromide". Key Engineering Materials 701 (julio de 2016): 18–22. http://dx.doi.org/10.4028/www.scientific.net/kem.701.18.

Texto completo

Resumen

Modification of multi-walled carbon nanotube (MWCNT) plays an important role to produce MWCNT crossbreeds that may be useful for exploration of new materials. In this report, characterization of dimethyl dioctadecylammonium bromide (DDOAB) modified multi-walled carbon nanotube (Mo-MWCNT) using Fourier Transform Infrared (FTIR) spectroscopy and Thermogravimetric analysis (TGA) and X-ray diffraction (XRD) is described. FTIR shows the presence of both aliphatic (CH stretching and CH bending) and ammonium (CN stretching) groups from DDOAB and the existence of C=C aromatic functional group from the structure of MWCNT in Mo-MWCNT spectra. This result was supported by TGA result which suggests that there are weight losses due to the degradation of DDOAB (between 250 °C to 500 °C) in the product. In addition, XRD pattern remain after modification suggesting attachment of MWCNT and DDOAB occurs at the surface of MWCNT.

Los estilos APA, Harvard, Vancouver, ISO, etc.

19

Jin, Seon-Mi, Jun Ho Hwang, Ke Wang, Jiangping Xu, Inhye Kim, Jintao Zhu y Eunji Lee. "Symmetry breaking of Au nanospheres confined in 1D nanocylinders: exploring helical assembly by 3D transmission electron microscopy". Materials Chemistry Frontiers 4, n.º 10 (2020): 3032–39. http://dx.doi.org/10.1039/d0qm00374c.

Texto completo

Resumen

The hybrid assemblies of polystyrene-tethered gold NPs are controlled by polymer chain stretching in a cylindrical confinement. The zigzag NP arrays observed in 2D TEM can be revealed into double- or triple-stranded helical NP arrays using 3D TEM.

Los estilos APA, Harvard, Vancouver, ISO, etc.

20

Castellote-Caballero, Yolanda, Maríe C. Valenza, Emilio J. Puentedura, César Fernández-de-las-Peñas y Francisco Alburquerque-Sendín. "Immediate Effects of Neurodynamic Sliding versus Muscle Stretching on Hamstring Flexibility in Subjects with Short Hamstring Syndrome". Journal of Sports Medicine 2014 (2014): 1–8. http://dx.doi.org/10.1155/2014/127471.

Texto completo

Resumen

Background. Hamstring injuries continue to affect active individuals and although inadequate muscle extensibility remains a commonly accepted factor, little is known about the most effective method to improve flexibility.Purpose. To determine if an isolated neurodynamic sciatic sliding technique would improve hamstring flexibility to a greater degree than stretching or a placebo intervention in asymptomatic subjects with short hamstring syndrome (SHS).Study Design. Randomized double-blinded controlled trial.Methods. One hundred and twenty subjects with SHS were randomized to 1 of 3 groups: neurodynamic sliding, hamstring stretching, and placebo control. Each subject’s dominant leg was measured for straight leg raise (SLR) range of motion (ROM) before and after interventions. Data were analyzed with a3×2mixed model ANOVA followed by simple main effects analyses.Results. At the end of the study, more ROM was observed in the Neurodynamic and Stretching groups compared to the Control group and more ROM in the Neurodynamic group compared to Stretching group.Conclusion. Findings suggest that a neurodynamic sliding technique will increase hamstring flexibility to a greater degree than static hamstring stretching in healthy subjects with SHS.Clinical Relevance. The use of neurodynamic sliding techniques to improve hamstring flexibility in sports may lead to a decreased incidence in injuries; however, this needs to be formally tested.

Los estilos APA, Harvard, Vancouver, ISO, etc.

21

Phimmasene, Soukvilay, Kittipong Tonmitra, Apirat Siritaratiwat y Arkom Kaewrawang. "Environmental Study on the Behavior of Water Drops with Circular Resin Insulator Material under DC Electric Field Stress". Advanced Materials Research 979 (junio de 2014): 111–14. http://dx.doi.org/10.4028/www.scientific.net/amr.979.111.

Texto completo

Resumen

The influence of damages on the insulator’s surface in the distribution system is investigated in this paper. The circular resin is used as the specimen under high voltage direct current (HVDC) between the electrodes with diameter of 2 mm and distance between both electrodes are 35 mm. There are three cases in the experiment and it was tested in environmental condition under dry surface, single droplet and double droplets. The HVDC had been applied to the electrodes, the level of applied were 5, 10, 15, 20, 25, 30 and 35 kV. The results show that the arc occurs rapidly in the case of single and double drops with compared to dry surface. The movements of the water drop of the single and doubles are pretty similar, but the arc occurs quickly in the double drop in comparison with single drop owing to double drops stretch to each other. The double drops take a lower voltage on stretching, whereas the single drop takes higher because the double drops have much more densities than single drop. Besides, the double drops act as a bridge allow the electrical field generated from both electrodes pulled them resulting in arcing easily. In conclusion, the droplets on the surfaces cause the leakage current and it has an effect on the stability of the distribution system.

Los estilos APA, Harvard, Vancouver, ISO, etc.

22

Li, Zhenlan, Tian Wang, Mengyue Shen, Tao Song, Jie He, Wei Guo, Zhen Wang y Jie Zhuang. "Comparison of Wuqinxi Qigong with Stretching on Single- and Dual-Task Gait, Motor Symptoms and Quality of Life in Parkinson’s Disease: A Preliminary Randomized Control Study". International Journal of Environmental Research and Public Health 19, n.º 13 (30 de junio de 2022): 8042. http://dx.doi.org/10.3390/ijerph19138042.

Texto completo

Resumen

The objective of this study was to investigate the therapeutic effect of Wuqinxi Qigong vs. stretching on single- and dual-task gait, motor symptoms, and quality of life in people with mild and moderate Parkinson’s disease (PD). This single-blind, randomized control trial included 40 participants with idiopathic PD who were randomized into the Wuqinxi Qigong (WQ) group or stretching group. Participants completed 12 weeks (two sessions/week) of intervention. The primary outcomes were gait parameters when performing single-task (comfortable pace) and dual-task (obstacle crossing, serial-3 subtraction and backward digit span) walking, including gait speed, stride length, and double support percentage. The secondary outcomes were ratings from the Movement Disorder Society Unified Parkinson’s Disease Rating Scale (MDS-UPDRS), results of the timed-up-and-go test (TUGT), results of the Mini-Balance Evaluation Systems Test (MiniBESTest), and responses from the 39-item Parkinson’s Disease Questionnaire (PDQ-39). All measures were assessed pre- and post-intervention. The WQ group demonstrated increased gait speed (p = 0.000) during the single task, and increased stride length (p = 0.001, p = 0.021) during the single-task and serial-3 subtraction task. Double support percentage significantly decreased (p = 0.004) in the WQ group during the obstacle crossing task, and also decreased (p = 0.045) in the stretching group during the single-task. TUGT (p = 0.005), MiniBESTest (p = 0.023) and PDQ-39 (p = 0.043) in the WQ group significantly improved, and both groups showed significant improvement in MDS-UPDRS after intervention. Wuqinxi Qigong is an effective method to improve single- and dual-task gait. While both exercises improve motor symptoms, Wuqinxi Qigong results in better mobility, balance and quality of life compared to stretching alone.

Los estilos APA, Harvard, Vancouver, ISO, etc.

23

Hamed, G. R. y M. Y. Huang. "Tensile and Tear Behavior of Anisotropic Double Networks of a Black-Filled Natural Rubber Vulcanizate". Rubber Chemistry and Technology 71, n.º 5 (1 de noviembre de 1998): 846–60. http://dx.doi.org/10.5254/1.3538513.

Texto completo

Resumen

Abstract Double networks of a black-filled natural rubber composition have been prepared by partially curing a sheet, stretching it, and then completing cure. Upon release, a double network retracts to a residual extension ratio, αr. Samples cut perpendicular to the stretch direction have stress—strain responses like the isotropic single network, while parallel samples have enhanced stiffness and tensile strength, and reduced extensibility. Tensile strength is rather weakly dependent on αr. Tear strengths of the double networks, determined using edge-cut strip specimens, exceed that of the single network for low αr. However, when αr is high, double networks have very low tear strengths. Consistent with previous studies, high tear strengths are associated with extensive longitudinal cracking.

Los estilos APA, Harvard, Vancouver, ISO, etc.

24

Norzawary, N. H. A., N. Bachok, F. M. Ali y N. A. A. Rahmin. "Double solutions and stability analysis of slip flow past a stretching/shrinking sheet in a carbon nanotube". Mathematical Modeling and Computing 9, n.º 4 (2022): 816–24. http://dx.doi.org/10.23939/mmc2022.04.816.

Texto completo

Resumen

A stagnation point flow past a stretching/shrinking surface in carbon nanotubes (CNTs) with slip effects is investigated in this paper. Applying transformations of similarity, the governing partial differential equations are modified to the nonlinear ordinary differential equations. Afterward, they are numerically solved in Matlab by the bvp4c solver. The single-wall CNTs and multi-wall CNTs are used, including water as a base fluid. The effects of the flow parameters are investigated, shown in the form of graphs, and physically evaluated for the dimensionless velocity, temperature, skin friction, and Nusselt numbers. According to our findings, the unique solution exists for stretching sheets, whereas non-unique solutions are obtainable for shrinking sheets. The stability analysis is utilized to discover which solution is stable.

Los estilos APA, Harvard, Vancouver, ISO, etc.

25

MATSUO, YASUTAKA, KUNIHARU IJIRO y MASATSUGU SHIMOMURA. "STRETCHING OF SINGLE DNA MOLECULES BY LANGMUIR–BLODGETT METHOD". International Journal of Nanoscience 01, n.º 05n06 (octubre de 2002): 695–99. http://dx.doi.org/10.1142/s0219581x02000917.

Texto completo

Resumen

We propose a new method that double-stranded DNA molecules can be stretched and immobilized on the clean glass substrate by using a lipid monolayer at the air–water interface. This method is based on the substrate lifting of Langmuir–Blodgett method. We observed fluorescence images of polyion complex films with a scanning near-field optical microscope (SNOM). As a result, straight fluorescent lines aligned parallel to the lifting direction were observed and it was considered that isolated single DNA molecules were extended to align on the substrate. This method is applied to various DNA molecules.

Los estilos APA, Harvard, Vancouver, ISO, etc.

26

Dong, Ruixin, Xunling Yan y Shenggang Liu. "The salt dependence of the stretching transition of double-stranded DNA molecules". Journal of Physics A: Mathematical and General 37, n.º 18 (21 de abril de 2004): 4977–84. http://dx.doi.org/10.1088/0305-4470/37/18/005.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

27

Hamed, G. R. y K. Umetsu. "Gum and Black-Filled Double Networks of cis-1,4-Polyisoprene Crosslinked with Sulfur Donors: Part I. Tensile Properties". Rubber Chemistry and Technology 78, n.º 1 (1 de marzo de 2005): 130–42. http://dx.doi.org/10.5254/1.3547866.

Texto completo

Resumen

Abstract Gum and black-filled double networks of cis-1,4 polyisoprene, crosslinked with sulfur donors, have been prepared by first partially curing sheets, then stretching them and completing cure. Double networks are anisotropic and exhibit a residual extension ratio λr, which is higher for filled compared to gum samples. Additionally, double networks of filled specimens have higher anisotropy than gum counterparts, presumably because carbon black promotes chain alignment and strain-crystallization. Tensile specimens cut parallel to the stretch direction are stiffer, less extensible, and sometimes stronger than simple isotropic networks, while perpendicular specimens have stress-strain responses much like that of the isotropic control.

Los estilos APA, Harvard, Vancouver, ISO, etc.

28

Sulalitha Priyankara, K. G. D., Sanjeeva Balasuriya y Erik Bollt. "Quantifying the Role of Folding in Nonautonomous Flows: The Unsteady Double-Gyre". International Journal of Bifurcation and Chaos 27, n.º 10 (septiembre de 2017): 1750156. http://dx.doi.org/10.1142/s0218127417501565.

Texto completo

Resumen

We analyze chaos in the well-known nonautonomous Double-Gyre system. A key focus is on folding, which is possibly the less-studied aspect of the “stretching+folding=chaos” mantra of chaotic dynamics. Despite the Double-Gyre not having the classical homoclinic structure for the usage of the Smale–Birkhoff theorem to establish chaos, we use the concept of folding to prove the existence of an embedded horseshoe map. We also show how curvature of manifolds can be used to identify fold points in the Double-Gyre. This method is applicable to general nonautonomous flows in two dimensions, defined for either finite or infinite times.

Los estilos APA, Harvard, Vancouver, ISO, etc.

29

Wang, Feng, Yu Hai Guo, Hua Peng Zhang y Hong Yan Tang. "Surface Refining Treatment of Filter Media". Advanced Materials Research 441 (enero de 2012): 593–97. http://dx.doi.org/10.4028/www.scientific.net/amr.441.593.

Texto completo

Resumen

In order to improve filtration efficiency and precision of the filter media, two methods of surface refining treatment were presented, which were the co-stretching PTFE micro-porous membrane and foam coating on nonwoven filter media. During the process of co-stretching, the pore diameters and thickness of the membrane were different on the surface. The double-layer PTFE base sheet was simultaneously stretched, which induced the reduction of pore sizes and uniform thickness of the filter media. After foam coating, the pore sizes of nonwoven filter media were reduced to under 10 μm because of the micro-pore membrane formed on the surface. Therefore, filtration efficiency and precision were remarkably increased.

Los estilos APA, Harvard, Vancouver, ISO, etc.

30

Akbar, Noreen Sher, C. M. Khalique y Z. H. Khan. "Double Diffusion Effects on Magnetohydrodynamic Non-Newtonian Fluid Nanoparticles". Journal of Computational and Theoretical Nanoscience 14, n.º 1 (1 de enero de 2017): 694–703. http://dx.doi.org/10.1166/jctn.2017.6260.

Texto completo

Resumen

In the present article, the double-diffusive natural convection of a micropolar nanofluid over a linearly stretching sheet is discussed. The flow equations are transformed into ordinary differential equations using similarity transformations. The numerical solutions are computed using shooting technique and compared with the literature for the special case of pure fluid flow and found to be in good agreement. Graphical results are presented to illustrate the effects of various fluid flow parameters on velocity, heat transfer, nanoparticle volume fraction, salt concentration, Nusselt number, Sherwood number and skin friction coefficient for both assisting and opposing flows.

Los estilos APA, Harvard, Vancouver, ISO, etc.

31

Laksee, S., W. Chitaka, K. Laohhasurayotin y C. Suwanchawalit. "Fabrication of zinc-aluminum layer double hydroxide thin films and their anionic adsorption performance". Digest Journal of Nanomaterials and Biostructures 17, n.º 1 (enero de 2022): 127–36. http://dx.doi.org/10.15251/djnb.2022.171.127.

Texto completo

Resumen

Layered double hydroxides (LDHs) are also known as hydrotalcite-like compounds or anionic clays. In this work, ZnAl-LDH films were prepared on aluminium (Al) plates by a hydrothermal technique using zinc nitrate solution as the precursors. ZnAl-LDHs films were characterized by SEM, EDX, XRD and FT-IR. The SEM analysis revealed that the ZnAl-LDH films with hierarchical nanoarchitectures on the surface of Al plates. EDX mapping and elemental analysis also showed that Zn, Al, and O dispersed uniformly on the aluminium substrates. XRD results were used to confirm the presence of ZnAl-LDH films as they appeared purely with the typical (003) and (006) peaks of LDH diffraction. The characteristic bands of bending vibrations due to the intercalating water, stretching vibration due to the overlapping signal of carbonate anion and nitrate anion were measured by FT-IR spectroscopy. The brucite structure also exhibited the OH-stretching vibration as well as the ZnO lattice vibration in the spectra. These ZnAl-LDH forms were evaluated for their removal performance against orange II dye solutions.

Los estilos APA, Harvard, Vancouver, ISO, etc.

32

Wu, Heng, Yani Zhang, Wenyu Yuan, Yingxin Zhao, Shaohong Luo, Xiaowen Yuan, Lianxi Zheng y Laifei Cheng. "Highly flexible, foldable and stretchable Ni–Co layered double hydroxide/polyaniline/bacterial cellulose electrodes for high-performance all-solid-state supercapacitors". Journal of Materials Chemistry A 6, n.º 34 (2018): 16617–26. http://dx.doi.org/10.1039/c8ta05673k.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

33

Mai, Thanh-Tam, Takahiro Matsuda, Tasuku Nakajima, Jian Ping Gong y Kenji Urayama. "Damage cross-effect and anisotropy in tough double network hydrogels revealed by biaxial stretching". Soft Matter 15, n.º 18 (2019): 3719–32. http://dx.doi.org/10.1039/c9sm00409b.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

34

Oh, Sung Joon y Jack L. Koenig. "Studies of Peroxide Curing of Polybutadiene/Zinc Diacrylate Blends by Fast FT-IR Imaging". Rubber Chemistry and Technology 73, n.º 1 (1 de marzo de 2000): 74–79. http://dx.doi.org/10.5254/1.3547581.

Texto completo

Resumen

Abstract Fast Fourier transform infrared (FT-IR) imaging measurements of cured polybutadiene(PBD)/zinc diacrylate(ZDA) showed a heterogeneous distribution of zinc diacrylate. The phase structures were classified as PBD-rich and ZDA-rich domains. Upon curing, the increase in the infrared aliphatic CH stretching mode at 2916 cm−1 and the decrease in unsaturated CH stretching mode at 3075 cm−1 were observed as the single bond crosslinks were formed at the expense of double bonds. In a solvent diffusion experiment with toluene of these cured blends, it was observed that more solvent is imbibed into the PBD-rich matrix than the ZDA-rich domains. The difference is due to the lower swelling ratio of ZDA-rich domains than that of PBD-rich matrix.

Los estilos APA, Harvard, Vancouver, ISO, etc.

35

Rudikov, S. I., V. Yu Tsviatkou y A. P. Shkadarevich. "Dynamic Range Compression of Infrared Images Based on Histogram Equalization with Edge Inversion". Doklady BGUIR 22, n.º 1 (28 de febrero de 2024): 108–15. http://dx.doi.org/10.35596/1729-7648-2024-22-1-108-115.

Texto completo

Resumen

The problem of compression of the dynamic range of infrared images is considered. To improve the quality of tone mapping of infrared images when their dynamic range is compressed and to simplify the control over the reproduction characteristics of infrared images, a dynamic range conversion algorithm based on adaptive histogram equalization with edge inversion is proposed. The essence of the algorithm consists in double reduction of the dynamic range of the infrared image with intermediate stretching, compression and overlapping of edges with inversion. To select the brightness interval and the degree of its stretching, the proposed algorithm uses the asymmetry coefficient. The algorithm makes it possible to improve some global and interval indicators of image reproduction quality by superimposing the edges of the histogram.

Los estilos APA, Harvard, Vancouver, ISO, etc.

36

Merkulov, B. H. y O. G. Sokolov. "Replacement of post-traumatic skin defects in children by tissue stretching with the use of endo-expanders". N.N. Priorov Journal of Traumatology and Orthopedics 1, n.º 2 (12 de junio de 2022): 9–13. http://dx.doi.org/10.17816/vto64662.

Texto completo

Resumen

In the clinic for pediatric trauma, CITO, replacement of post-traumatic skin defects by tissue stretching was performed in 11 patients aged 4 to 14 years. 16 expanders were implanted (5 patients with two expanders). Implantation was performed on the lower leg (5 patients), in the projection of the knee joint (2), on the hand, thigh, scalp and in Filatov's stem (one patient each). The area of the replaced cicatricial defects was 20 cm2 on the hand, up to 135 cm2 on the lower leg, and 160 cm2 on the scalp. Preference will be given to double-expander stretching with expanders located on opposite sides of the cicatricial defect. Among the complications, the formation of pressure ulcers of the skin over the valve tube, violation of the tightness of the balloons were noted. Out of 11 patients, the desired result was obtained in 9. The method of tissue stretching with the help of expanders can be used in children to replace post-traumatic defects of the skin of the limbs and scalp.

Los estilos APA, Harvard, Vancouver, ISO, etc.

37

Weng, Yih-Ming, Ru-Hui Weng, Chin-Yin Tzeng y Wenlung Chen. "Structural Analysis of Triacylglycerols and Edible Oils by Near-Infrared Fourier Transform Raman Spectroscopy". Applied Spectroscopy 57, n.º 4 (abril de 2003): 413–18. http://dx.doi.org/10.1366/00037020360625952.

Texto completo

Resumen

Fourier transform Raman spectroscopy was employed for structural analysis of triacylglycerols and edible oils. Raman spectra sensitively reflected structural changes in oils. Even slight structural fluctuation between triacylglycerols and free fatty acids led to obvious differences in Raman bands as shown by C–O–C stretching from 800 to 1000 cm−1 and the band at 1742 cm−1. Structural difference in geometric isomers was easily distinguished as proved by C = C stretching at 1655 cm−1 ( cis) shifting to 1668 cm−1 ( trans) and by =C–H in-plane bending at 1266 cm−1 in cis disappearing in the trans isomer. Raman intensity at 1266, 1302, and 1655 cm−1 changed concomitantly with the change of double-bond content in oils. It showed that FT-Raman was capable of precisly reflecting the content of double bonds in oils. A linear correlation with high consistency between the Raman intensity ratio ( v1655 /v1444) and the iodine value was obtained for commercial oils. Based on the results, FT-Raman spectroscopy proved itself a simple and rapid technique for oil analysis since each measurement could be directly completed in 3 min without any sample modifications.

Los estilos APA, Harvard, Vancouver, ISO, etc.

38

Sadaoka, Kana y Yoshitaka Saga. "Effects of the central metal on stretching vibrational bands of the peripheral carbonyl moieties in formylated chlorophyll derivatives studied by Fourier-transform infrared spectroscopy". Journal of Porphyrins and Phthalocyanines 18, n.º 06 (junio de 2014): 506–12. http://dx.doi.org/10.1142/s1088424614500242.

Texto completo

Resumen

The vibrational properties of metal complexes of monoformylated and diformylated chlorophyll derivatives were compared with those of the corresponding free-base chlorins to unravel the effects of the central metal on the carbonyl stretching vibration modes of the peripheral oxygen functional groups in the chlorin macrocycle by means of FTIR spectroscopy. The 3- C = O stretching vibrational bands of a 3-formyl group were shifted to lower wavenumbers by insertion of Zn and Cu into the center of the 3-formyl free-base chlorin. In contrast, the 7- and 8- C = O stretching vibrational bands of the formyl groups linked to the B-ring of the chlorin macrocycle were barely shifted even if 7- and 8-formyl free-base chlorins were metalated. The down-shifts of the 3- C = O and few shifts of the 7-/8- C = O vibrational stretching bands were in line with the results of DFT calculations. The difference in the effects of the central metal on the vibrational properties between the formyl group in the A-ring and those in the B-ring is ascribable to the different conjugation manners with the adjacent π-system: the 3-formyl group was connected to the chlorin 18π-system, whereas the 7-/8-formyl groups were conjugated to the rather isolated C 7– C 8 double bond. The 13- C = O stretching vibrational bands were shifted to lower wavenumbers by metalation. These down-shifts can also be rationalized by invoking the conjugation of the 13-keto group with the chlorin 18π-system.

Los estilos APA, Harvard, Vancouver, ISO, etc.

39

Vialleron, Thomas, Arnaud Delafontaine, Sebastien Ditcharles, Paul Fourcade y Eric Yiou. "Effects of stretching exercises on human gait: a systematic review and meta-analysis". F1000Research 9 (13 de agosto de 2020): 984. http://dx.doi.org/10.12688/f1000research.25570.1.

Texto completo

Resumen

Background: Stretching is commonly used in physical therapy as a rehabilitation tool to improve range of motion and motor function. However, is stretching an efficient method to improve gait, and if so, for which patient category? Methods: A systematic review of randomized and non-randomized controlled trials with meta-analysis was conducted using relevant databases. Every patient category and every type of stretching programs were included without multicomponent programs. Data were meta-analysed where possible. Estimates of effect sizes (reported as standard mean difference (SMD)) with their respective 95% confidence interval (95% CI) were reported for each outcome. The PEDro scale was used for the quality assessment. Results: Twelve studies were included in the analysis. Stretching improved gait performance as assessed by walking speed and stride length only in a study with a frail elderly population, with small effect sizes (both SMD= 0.49; 95% CI: 0.03, 0.96; PEDro score: 3/10). The total distance and the continuous walking distance of the six-minute walking test were also improved only in a study in an elderly population who had symptomatic peripheral artery disease, with large effect sizes (SMD= 1.56; 95% CI: 0.66, 2.45 and SMD= 3.05; 95% CI: 1.86, 4.23, respectively; PEDro score: 5/10). The results were conflicting in healthy older adults or no benefit was found for most of the performance, spatiotemporal, kinetic and angular related variables. Only one study (PEDro score: 6/10) showed improvements in stance phase duration (SMD=-1.92; 95% CI: -3.04, -0.81), swing phase duration (SMD=1.92; 95 CI: 0.81, 3.04), double support phase duration (SMD= -1.69; 95% CI: -2.76, -0.62) and step length (SMD=1.37; 95% CI: 0.36, 2.38) with large effect sizes. Conclusions: There is no strong evidence supporting the beneficial effect of using stretching to improve gait. Further randomized controlled trials are needed to understand the impact of stretching on human gait.

Los estilos APA, Harvard, Vancouver, ISO, etc.

40

Vialleron, Thomas, Arnaud Delafontaine, Sebastien Ditcharles, Paul Fourcade y Eric Yiou. "Effects of stretching exercises on human gait: a systematic review and meta-analysis". F1000Research 9 (30 de octubre de 2020): 984. http://dx.doi.org/10.12688/f1000research.25570.2.

Texto completo

Resumen

Background: Stretching is commonly used in physical therapy as a rehabilitation tool to improve range of motion and motor function. However, is stretching an efficient method to improve gait, and if so, for which patient category? Methods: A systematic review of randomized and non-randomized controlled trials with meta-analysis was conducted using relevant databases. Every patient category and every type of stretching programs were included without multicomponent programs. Data were meta-analysed where possible. Estimates of effect sizes (reported as standard mean difference (SMD)) with their respective 95% confidence interval (95% CI) were reported for each outcome. The PEDro scale was used for the quality assessment. Results: Twelve studies were included in the analysis. Stretching improved gait performance as assessed by walking speed and stride length only in a study with a frail elderly population, with small effect sizes (both SMD= 0.49; 95% CI: 0.03, 0.96; PEDro score: 3/10). The total distance and the continuous walking distance of the six-minute walking test were also improved only in a study in an elderly population who had symptomatic peripheral artery disease, with large effect sizes (SMD= 1.56; 95% CI: 0.66, 2.45 and SMD= 3.05; 95% CI: 1.86, 4.23, respectively; PEDro score: 5/10). The results were conflicting in healthy older adults or no benefit was found for most of the performance, spatiotemporal, kinetic and angular related variables. Only one study (PEDro score: 6/10) showed improvements in stance phase duration (SMD=-1.92; 95% CI: -3.04, -0.81), swing phase duration (SMD=1.92; 95 CI: 0.81, 3.04), double support phase duration (SMD= -1.69; 95% CI: -2.76, -0.62) and step length (SMD=1.37; 95% CI: 0.36, 2.38) with large effect sizes. Conclusions: There is no strong evidence supporting the beneficial effect of using stretching to improve gait. Further randomized controlled trials are needed to understand the impact of stretching on human gait.

Los estilos APA, Harvard, Vancouver, ISO, etc.

41

Afanasyev, Alexander Y. y Alexey V. Onufriev. "Stretching of long double-stranded DNA and RNA described by the same model". Biophysical Journal 121, n.º 3 (febrero de 2022): 65a. http://dx.doi.org/10.1016/j.bpj.2021.11.2391.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

42

Srinivasacharya, Darbhashayanam y Pashikanti Jagadeeshwar. "Flow over an Exponentially Stretching Sheet with Double Dispersion and Convective Thermal Condition". Mathematical Modelling of Engineering Problems 6, n.º 2 (20 de junio de 2019): 300–308. http://dx.doi.org/10.18280/mmep.060219.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

43

Zhao, Feihu, Joose Kreutzer, Sami Pajunen y Pasi Kallio. "Mechanical Analysis of a Pneumatically Actuated Concentric Double-Shell Structure for Cell Stretching". Micromachines 5, n.º 4 (16 de octubre de 2014): 868–85. http://dx.doi.org/10.3390/mi5040868.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

44

Li, Zi, Chong-Yu Wang, Xu Zhang, San-Huang Ke y Weitao Yang. "Transport properties of an armchair carbon nanotube with a double vacancy under stretching". Journal of Physics: Condensed Matter 20, n.º 34 (6 de agosto de 2008): 345225. http://dx.doi.org/10.1088/0953-8984/20/34/345225.

Texto completo

Los estilos APA, Harvard, Vancouver, ISO, etc.

45

Wu, Yao Peng. "Study on Bi-Stable Behaviors of Double-Layered Cylindrical Shell". Advanced Materials Research 243-249 (mayo de 2011): 5981–84. http://dx.doi.org/10.4028/www.scientific.net/amr.243-249.5981.

Texto completo

Resumen

Bi-stable structure can be stable in both its extended and coiled forms. As a novel deployable structure, it shows a broad application prospect in the field of aeronautics and civil engineering, etc. Considered two cylindrical shells having the same flattening configurations, they can be closely bound together by applying external forces. And the corresponding double-layered cylindrical shell model is proposed. Expressions for the bending and stretching strain energies of the cylindrical shells are presented. Calculations show that total strain energy has two local minimal values, which reveals that the double-layered cylindrical shell has its bi-stability. The corresponding rolled-up radii are thus determined.

Los estilos APA, Harvard, Vancouver, ISO, etc.

46

Hiroe, Tetsuyuki, Kazuhito Fujiwara, Hidehiro Hata, Kiyotaka Tsutsumi, Takuya Igawa y Wataru Yamashita. "Explosively Driven Fragmentation Behavior for Structural Components and Shatterproof Effect of Wall Doubling". Materials Science Forum 673 (enero de 2011): 191–96. http://dx.doi.org/10.4028/www.scientific.net/msf.673.191.

Texto completo

Resumen

One-dimensional symmetrical explosive loadings are applied to expand structural components: tubular cylinders, spherical shells and rings of 304 stainless steel and double and single walled cylinders of an aluminum alloy, A5052 to fragmentation, and the effects of wall thicknesses, explosive driver diameters and the constant proportionality of the in-plane biaxial stretching rates are investigated on the deformation and fracture behavior of three types of single walled structures and shatterproof behavior for double walled cylinders experimentally and numerically. In the cylinder tests, the driver is a column of high explosive PETN, inserted coaxially into the bore of a cylinder and initiated by exploding a fine wire bundle at the column axis using a discharge current. In case of the ring tests, ring specimens are placed onto a cylinder charged with the PETN as an expansion driver, and for sphere tests, a specimen filled with the PETN is also initiated by exploding a fine copper wire line with small length located at the central point. Observation results of deformation have shown the final maximum in-plane stretching rate order of , and fracture evaluations on recovered fragments are discussed indicating the need of modified fragmentation model for the structural components. In the double walled cylinder tests, only for lowermost amount of the explosive the outer cylinder has almost caught the fragments of inner cylinder, revealing that the damage phenomena are much different from those for single walled ones.

Los estilos APA, Harvard, Vancouver, ISO, etc.

47

Semchenko, Igor V., Ivan S. Mikhalka, Andrey L. Samofalov y Sergei A. Khakhomov. "Controlling the Shape of a Double DNA-like Helix as an Element of Metamaterials". Photonics 11, n.º 9 (23 de agosto de 2024): 788. http://dx.doi.org/10.3390/photonics11090788.

Texto completo

Resumen

The aim of the article is to study the forces arising in a conductive DNA-like double helix in the field of a microwave electromagnetic wave. These forces must be considered for both actual DNA molecules and double DNA-like helices that serve as components of metamaterials and metasurfaces. The helix comprises twenty-and-a-half turns and has geometric parameters proportional to the size of an actual DNA molecule. The forces acting on the strands of a double helix, both in the central region and at the edges of the helix, are investigated. It has been demonstrated that the aforementioned forces induce a change in the shape of the helix, specifically the mutual repulsion of the strands, as well as their stretching and twisting in the field of electromagnetic waves. Consequently, exposure to an electromagnetic wave under half-wave resonance can damage the double helix. Conversely, the impact of electromagnetic waves has the potential to introduce novel avenues for controlling the shape of the double helix.

Los estilos APA, Harvard, Vancouver, ISO, etc.

48

Garaboa-Paz, D. y V. Pérez-Muñuzuri. "A method to calculate finite-time Lyapunov exponents for inertial particles in incompressible flows". Nonlinear Processes in Geophysics 22, n.º 5 (5 de octubre de 2015): 571–77. http://dx.doi.org/10.5194/npg-22-571-2015.

Texto completo

Resumen

Abstract. The present study aims to improve the calculus of finite-time Lyapunov exponents (FTLEs) applied to describe the transport of inertial particles in a fluid flow. To this aim, the deformation tensor is modified to take into account that the stretching rate between particles separated by a certain distance is influenced by the initial velocity of the particles. Thus, the inertial FTLEs (iFTLEs) are defined in terms of the maximum stretching between infinitesimally close trajectories that have different initial velocities. The advantages of this improvement, if compared to the standard method (Shadden et al., 2005), are discussed for the double-gyre flow and the meandering jet flow. The new method allows one to identify the initial velocity that inertial particles must have in order to maximize their dispersion.

Los estilos APA, Harvard, Vancouver, ISO, etc.

49

Yang, Peng Fei, Jun Ying Li y Tian Duo Li. "Characterization on Propylene Oxide Polymerization with In Situ FT-IR". Advanced Materials Research 160-162 (noviembre de 2010): 60–64. http://dx.doi.org/10.4028/www.scientific.net/amr.160-162.60.

Texto completo

Resumen

In-situ FT-IR technique is used to investigate the polymerization of propylene oxide with potassium t-butoxide as initiator. The epoxy absorbance at 828 cm-1 is the most useful peaks to monitor the reaction. The absorbance of C-O-C stretching vibration at 1107 cm-1 is very strong and also very useful. Yet, the absorbance of C-H stretching vibration in 3000~2800 cm-1 region is very weak and not reliable for In-situ FT-IR analysis. By monitoring the consumption of propylene oxide, the polymerization rate constant k at 33°C was calculated out and an interesting auto acceleration phenomenon was discovered. Moreover, the chain-transfer process was analyzed by measuring the formation of C=C double bonds, which clarified a former confusion about the course of propylene oxide rearrangement.

Los estilos APA, Harvard, Vancouver, ISO, etc.

50

Zakir, Zahid. "Slowing time cosmology with initial violetshift and three types of redshift". QUANTUM AND GRAVITATIONAL PHYSICS 2 (16 de agosto de 2021): 1–20. http://dx.doi.org/10.9751/qgph.2-012.7533.

Texto completo

Resumen

In general relativity, the stretching of the wavelengths of photons in the expanding universe occurs along the path and does not depend on the velocity of the source. Therefore, the photons from the sources at rest relative to us did not have, and from the sources comoving the expansion there was an initial Doppler redshift, and then on the way both photon fluxes acquired a stretching redshift. As the result, the redshift of the comoving the expansion sources should be at least doubled. But observations show a single redshift already in the linear part, and therefore in cosmological models only with redshifts (Friedmann's and others) there was the double redshift problem with one hundred percent discrepancy between theory and observations. The observational fact of single redshifts means that the photons should have an initial violetshift, which was compensated for along the way by one of two types of redshift. In the model of slowing time cosmology (STC) proposed in 2020, the rate of proper times was higher in earlier epochs, which led to the violetshift, compensated along the way by the stretching redshift. As a result, in STC the observed shift is reduced to the initial Doppler redshift, to which the gravitational redshift is added for distant objects. The relativistic aberration then leads to dimming of the apparent luminosities. The basic relations of STC are presented, including the “distance modulus – redshift”, which are consistent with observations at new values of cosmological parameters. Evolution in early epochs and its influence on the properties of CMB are also discussed. In STC the light velocity was higher in the past and for this reason it has no previously known cosmological problems.

Los estilos APA, Harvard, Vancouver, ISO, etc.

Artículos de revistas sobre el tema "Double stretching"

Crea una cita precisa en los estilos APA, MLA, Chicago, Harvard y otros