ライフサイエンスコーパス: acoustic wave

1 f magnitude smaller than that of the driving acoustic wave.

2 , is controlled by a radio frequency surface acoustic wave.

3 f disk-in-sphere endoskeletal droplets using acoustic wave.

4 emitted by the plasma, together with an ion- acoustic wave.

5 tude lower than the frequency of the driving acoustic wave.

6 ur method uses tilted-angle standing surface acoustic waves.

7 iate and cavitate bubbles in the presence of acoustic waves.

8 t to transient or continuous perturbation by acoustic waves.

9 heory applies equally to electromagnetic and acoustic waves.

10 ubstrate foil surface due to laser-generated acoustic waves.

11 and permeabilization of cell membranes with acoustic waves.

12 cavity, where the bubble is resonated using acoustic waves.

13 ubwavelength-resolution manipulation of bulk acoustic waves.

14 is method, we simultaneously apply and sense acoustic waves.

15 information of an optical pulse sequence via acoustic waves.

16 has been demonstrated in electromagnetic and acoustic waves.

17 icinity of the observer, and transduced into acoustic waves.

18 rk provides a different way for manipulating acoustic waves.

19 bits that couple to short-wavelength surface acoustic waves(4-10), probing the properties of the atom

20 technique that leverages an entanglement of acoustic wave actuation and the spin of a fluidic drople

21 rdigital transducers with the pulsed surface acoustic wave actuation, GRADE can achieve tunable and d

22 g the electrode geometry, we determined that acoustic waves alone are not responsible for poration of

23 Directing acoustic waves along curved paths is critical for applic

24 s, leading to the highest performing surface acoustic wave amplifiers ever developed in terms of gain

25 k position can be estimated by measuring the acoustic wave amplitudes from the marker, using a single

26 e principles and different configurations of acoustic wave and acoustic streaming for the manipulatio

27 These include: Bulk Acoustic Wave and Surface Acoustic Wave devices, micro-

28 By exploiting surface acoustic waves and a coupling layer technique, cells are

29 modes induced by the evanescent guided Lamb acoustic waves and remained Landau undamped due to fermi

30 asurface object is autonomously guided by an acoustic wave, and tractor beaming, where a metasurface

31 itous at interfaces with optical, seismic or acoustic waves, and also with electron, neutron or atom

32 how that bringing the metasurface physics of acoustic waves, and its full arsenal of tools, to the do

33 for valley states, robust routing of surface acoustic waves, and spatial modulation of group velociti

34 o far one of the very few examples of a bulk acoustic wave aptasensor that is able to directly detect

35 Acoustic waves are a possible reusable method to extingu

36 Our work shows that acoustic waves are an effective, contact-free means to c

37 nals in 3D space because the X-ray generated acoustic waves are of a spherical nature and propagate i

38 uniform heating beam, laser-induced surface acoustic waves are strongly influenced by surface heatin

39 lusion metamaterial has the ability to guide acoustic waves around the obstacles and accurately recre

40 ng pulsed piezoelectric transducer-generated acoustic waves at the surface of a liquid, resulting in

41 sipation mechanisms: plastic deformation and acoustic wave attenuation.

42 Here, we demonstrate standing surface acoustic wave based "acoustic tweezers" that can trap an

43 MEMS fabrication of acoustic wave based biosensors enables device miniaturiz

44 The acoustic wave based MEMS devices reported in the literat

45 ed of asymmetric pillars that can manipulate acoustic waves based on the pillars' angular orientation

46 This paper presents a review of acoustic-wave based MEMS devices that offer a promising

47 irable for improving the performance of many acoustic wave-based applications.

48 Surface acoustic wave-based e-skin offers highly sensitive, low-

49 ating deep in the adiabatic regime, the bulk acoustic wave (BAW) modes of solid SiC disks are mostly

50 urface acoustic wave (SAW) actuator and bulk acoustic wave (BAW) trapping array to enable multiplexed

51 coustic waves in the system relative to bulk acoustic wave (BAW)-based actuation, which suppresses Ra

52 ted by the narrow-frequency bandwidth of the acoustic waves because of the large attenuation for high

53 henomena: highly nonlinear distortion of the acoustic wave before it hits the droplet and focusing of

54 evidence for the hydrodynamic nature of the acoustic wave/biomolecule interaction at a solid/liquid

55 st label-free real-time ultra-high frequency acoustic wave biosensor prototype capable of detecting t

56 and microfluidics are easily constructed for acoustic wave biosensors, such as the Love wave device d

57 cteristic sample input in the laser-produced acoustic wave can be used for the creation of a statisti

58 ical and/or electrical cable communications, acoustic waves can be simply and effectively coupled int

59 Acoustic waves can be used to accurately position cells

60 Here, we demonstrate that low-power standing acoustic waves can be used to guide, block, focus, and s

61 fluidic channel walls and travelling surface acoustic waves can generate spatially variable acoustic

62 cting objects, the evolution of the radiated acoustic waves carries information on the source.

63 oherent optical coupling to Gaussian surface acoustic wave cavities with small mode volumes and high

64 it is piezoelectrically coupled to a surface acoustic wave cavity, realising circuit quantum acoustod

65 Rendering objects invisible to impinging acoustic waves (cloaking) and creating acoustic illusion

66 ng such a zero-index medium, we demonstrated acoustic wave collimation emitted from a point source.

67 It could be an acoustic wave, detected by an auditory organ as sound an

68 ably, incorporating a small, 100 MHz surface acoustic wave device (SAW) solves this problem.

69 er-layer deposited on the surface of a shear acoustic wave device and supported a Love wave.

70 y upon specific binding on the surface of an acoustic wave device.

71 Surface acoustic wave devices are key components for processing

72 Few types of acoustic wave devices could be integrated in microfluidi

73 hese include: Bulk Acoustic Wave and Surface Acoustic Wave devices, micro- and nano-cantilever sensor

74 the responses of an array of polymer-coated acoustic wave devices.

75 nspection, mechanical vibration, and surface acoustic wave devices; precise manipulation of surface R

76 ipation mechanisms, such as bond rupture and acoustic wave dissipation, in response to high-strain-ra

77 g oscillations well below the frequencies of acoustic waves, down to much longer periods typical of g

78 tudied, such as heating by gravity waves and acoustic waves emanating from the lower atmosphere(2,11-

79 t potential expressions used for solving the acoustic wave equation and propose a unified framework f

80 Mixing is provided by way of surface acoustic wave excitation; this high-frequency vibration

81 Surface acoustic waves excited on the substrate can manipulate a

82 acoustics, Lord Rayleigh showed that surface acoustic waves exhibit a characteristic elliptical parti

83 ieve real-time control of a standing surface acoustic wave field, which enables flexible manipulation

84 constrained by the limited complexity of the acoustic wave field.

85 oribbons a potential candidate for use as an acoustic wave filter with applications in tunable gate-c

86 e functionalities at these frequencies, e.g. acoustic wave filtering, that are currently in widesprea

87 and activate a pulsed highly focused surface acoustic wave for single-cell level sorting.

88 sing low-intensity, low-frequency ultrasound acoustic waves for understanding of interfacial implant

89 r capabilities for slowing down and trapping acoustic waves for various applications such as metastru

90 The scattered acoustic waves from this time-varying system experience

91 ocusing and highly focused traveling surface acoustic wave (FTSAW) to sort cells with high recovery r

92 We show that the acoustic wave generated by FOC can directly activate ind

93 louin scattering experiment, in which an ion-acoustic wave generated by the beating of electromagneti

94 nge-verification method for proton beam with acoustic waves generated from spherical metal markers.

95 Using the acoustic waves generated in response to the absorption o

96 plying shear waves to the liver, a pneumatic acoustic wave generator was developed and tested by usin

97 rformance of guided shear horizontal surface acoustic wave (guided SH-SAW) devices on LiTaO3 substrat

98 nd high yield using a highly focused surface acoustic wave (HFSAW) with a beam width around 50 mum.

99 espite many similarities between optical and acoustic waves, high-acoustic-index-contrast phononic wa

100 actless manipulation of microparticles using acoustic waves holds promise for applications ranging fr

101 h the two independent relative phases of the acoustic wave in the three waveguides.

102 ta-skin" insulator, which is able to confine acoustic waves in an all-angle and wide spectrum range d

103 The bulk acoustic waves in ME antennas stimulate magnetization os

104 tics concerns operations with high-frequency acoustic waves in solid media in a similar way to how tr

105 The critical keyhole instability generates acoustic waves in the melt pool that provide additional

106 AW-based excitation generates high-frequency acoustic waves in the system relative to bulk acoustic w

107 lens capable of steering the convergence of acoustic waves in three-dimensional space.

108 itive readout, we use this to demonstrate an acoustic wave interference effect, similar to atomic coh

109 A microstructured pillar is used to couple acoustic waves into the fluid channel for noncontact par

110 eanwhile, the SVTAS is applicable to convert acoustic waves into TIEL signals in contact-separation m

111 The acoustic wave is focused into a small geometrical volume

112 of quartz, a temperature-compensated surface acoustic wave is generated via an interdigital transduce

113 The acoustic wave is locally coupled into the microfluidic c

114 ing unidirectional transmission property for acoustic waves is extremely desirable in many practical

115 lower part of the MT film, penetrated by the acoustic wave, is able to detect a pronounced cationic d

116 -ray photon pulses synchronized to a surface acoustic wave launcher, we achieve an effective time res

117 The acoustic waves link different optical pulses, capturing

118 metasurface could enable a new degree of the acoustic wave manipulating and be applied in the functio

119 as versatile platforms for various advanced acoustic wave manipulation and signal modulation, leadin

120 Surface acoustic wave mediated transductions have been widely us

121 Methods of integration of the acoustic wave MEMS devices in the microfluidic systems a

122 n integrated array of polymer-coated surface acoustic wave microsensors is described.

123 single electron may be captured in a surface acoustic wave minimum and transferred from one quantum d

124 placements rules out the presence of magneto-acoustic wave modes.

125 Atmospheric standing acoustic waves near the source produced oscillatory peak

126 t corona discharge (CD) coupled to a surface acoustic wave nebulization (SAWN) device enhanced sampli

127 d desorption performance for APCI, a surface acoustic wave nebulization (SAWN) device was implemented

128 Surface acoustic wave nebulization (SAWN) is a new technique tha

129 Surface acoustic wave nebulization (SAWN) is a novel method to t

130 anisotropies in longitudinal and transverse acoustic waves occur, especially along the [110] directi

131 At short beam pulse, specific high-frequency acoustic waves of 1.62 MHz originating from the marker w

132 ed by a Gunn diode oscillator, with coherent acoustic waves of frequency ~100 GHz, generated by pulse

133 Cell sorting by acoustic waves offers a means to separate cells on the b

134 are based on Brillouin light scattering from acoustic waves or phonons in the GHz range, providing a

135 The MARS device generates radial shear acoustic waves over a broad bandwidth that are unaffecte

136 re has good focusing intensity and can focus acoustic waves over a wide range of incidence angles wit

137 highly efficient overlap between optical and acoustic waves over an imaging depth of >6 mm in D2O med

138 new avenue for controlling the properties of acoustic wave patterns, and benefit potential applicatio

139 ing qubit to a bath of piezoelectric surface acoustic wave phonons enables a novel platform for inves

140 ic emission and capture of itinerant surface acoustic wave phonons, enabling the quantum entanglement

141 Phonons, and in particular surface acoustic wave phonons, have been proposed as a means to

142 The acoustic wave produced alongside laser-induced plasmas c

143 uidic channel using shear-horizontal surface acoustic waves, producing an array of virtual electrodes

144 s from molecules in the gas within which the acoustic wave propagates.

145 yrating electric field produced by a surface acoustic wave propagating on a slab of lithium niobate.

146 ning the dose calculations with modelling of acoustic-wave propagation.

147 can be detected by monitoring changes in the acoustic wave properties such as velocity, attenuation,

148 We show that acoustic waves provide a fertile ground to apply the ano

149 We study the effect of a propagating surface acoustic wave (PSAW) with different frequencies on parti

150 namics can be detected by means of a surface-acoustic-wave quantum dot(14), this method does not allo

151 for numerous applications including surface acoustic wave radio frequencies devices and integrated o

152 -mean-square (RMS) phase noise by minimizing acoustic wave reflections from electrode edges, thus ena

153 id manipulation and measurement with surface acoustic waves rely on the efficient transmission of aco

154 on of the acoustic waveform near the surface acoustic wave resonance frequency of the levitated drop

155 n is realized by exciting high-overtone bulk acoustic wave resonances (HBAR) in the photonic stack.

156 Thin film bulk acoustic wave resonator (FBAR) devices supporting simult

157 aviolet (UV) light sensor based on film bulk acoustic wave resonator (FBAR) is proposed.

158 The multi-mode composite high-overtone bulk acoustic wave resonator (HBAR) is a popular phonon sourc

159 d directly by use of higher harmonics of the acoustic wave resonator and indirectly via temperature.

160 rimentally demonstrate a high-frequency bulk acoustic wave resonator that is strongly coupled to a su

161 y shape-engineering of a single-contact bulk acoustic wave resonator, acoustic vortices are generated

162 The microchip, a commercial surface acoustic wave resonator, contains an array of interdigit

163 s and presented in this review are film bulk acoustic wave resonators (FBAR), surface acoustic waves

164 study, we fabricate several lithium niobate acoustic wave resonators and apply different processing

165 eme frequency scaling opportunities for bulk acoustic wave resonators for beyond-5 G applications.

166 g a scalable platform comprising two surface acoustic wave resonators on separate substrates, each co

167 equency (f = omega/2pi) using high-frequency acoustic wave resonators.

168 thiophene) films, using thickness shear mode acoustic wave resonators.

169 s propagates through a thin metal foil as an acoustic wave, resulting in desorption of neutral molecu

170 Our platform integrates a surface acoustic wave (SAW) actuator and bulk acoustic wave (BAW

171 carried in a potential minimum of a surface acoustic wave (SAW) and is transported to a region of ho

172 Here we report the use of a surface acoustic wave (SAW) atomizer for fast sample handling in

173 re diagnostic device which harnesses surface acoustic wave (SAW) biochips, to detect HIV in a finger

174 ing a low-dead-volume polymer-coated surface acoustic wave (SAW) detector.

175 We describe the fabrication of a surface acoustic wave (SAW) device on a LiNbO(3) piezoelectric t

176 An 82 MHz surface acoustic wave (SAW) device was placed in contact with th

177 Surface acoustic wave (SAW) devices are widely used for signal p

178 ectra of specifically functionalized surface acoustic wave (SAW) devices concurrently with analyte ex

179 e-blood manipulation capabilities of surface acoustic wave (SAW) driven counterflow micropumps.

180 ogies is based on the development of surface acoustic wave (SAW) flexible biosensors, which are highl

181 The sensor is based on a surface acoustic wave (SAW) gravimetric transducer modified with

182 We report ZnO/glass surface acoustic wave (SAW) humidity sensors with high sensitivi

183 Here we consider the use of surface acoustic wave (SAW) irradiation of C. elegans worms-with

184 ea alumina coatings were prepared on surface acoustic wave (SAW) mass balances.

185 While surface acoustic wave (SAW) microcentrifugation has been demonst

186 n Acoustic Gym on a chip through the surface acoustic wave (SAW) microfluidic technology to precisely

187 coupled to a zinc oxide (ZnO)-based surface acoustic wave (SAW) resonator.

188 ection of odorant molecules based on surface acoustic wave (SAW) resonators coated with odorant-bindi

189 ection of odorant molecules based on surface acoustic wave (SAW) resonators is presented.

190 (RESS), and deposited directly onto surface acoustic wave (SAW) resonators.

191 The use of polymer coated surface acoustic wave (SAW) sensor arrays is a very promising te

192 104 MHz lithium tantalate (LiTaO(3)) surface acoustic wave (SAW) sensor have been used to investigate

193 udy is to investigate a microfluidic surface acoustic wave (SAW) sensor platform capable of monitorin

194 rs collected from six polymer-coated surface acoustic wave (SAW) sensors were used in Monte Carlo sim

195 ated using MOF-functionalized quartz surface acoustic wave (SAW) sensors.

196 f combining molecular imprinting and surface acoustic wave (SAW) technologies for the selective and l

197 MMP-8) using specific antibodies and surface acoustic wave (SAW) technology.

198 energy relationships (LSERs) and the surface acoustic wave (SAW) transducers being mass sensitive.

199 Surface acoustic wave (SAW) vapor sensors with polymeric sorbent

200 trate that the propagation path of a surface acoustic wave (SAW), excited with an interdigitated tran

201 In this work, we present a surface acoustic wave (SAW)-based device that integrates a Fabry

202 uartz microcrystal balance (QMB) and surface acoustic wave (SAW).

203 Surface acoustic waves (SAW) and associated devices are ideal fo

204 SiO(2)-cover layer, shear horizontal surface acoustic waves (SAW) are excited and detected by a set o

205 e introduce highly focused traveling surface acoustic waves (SAW) at high frequencies between 193 and

206 Surface acoustic waves (SAW) generated by laser-based ultrasound

207 hanical disruption by high frequency surface acoustic waves (SAW) is presented as an appealing altern

208 ulk acoustic wave resonators (FBAR), surface acoustic waves (SAW) resonators and SAW delay lines.

209 We exploit the mechanical action of surface acoustic waves (SAW) to differentially lyse human cancer

210 Converging surface acoustic waves (SAW) with controlled amplitude are gener

211 opagating potential traps induced by surface acoustic waves (SAW).

212 roparticles and cells in paper using surface acoustic waves (SAW).

213 e with an ultra-high-frequency (UHF) surface-acoustic-wave (SAW) based lab-on-chip (LoC).

214 er-billion range using an integrated surface-acoustic-wave (SAW) sensor are achieved.

215 ness-shear-mode resonator (TSMR) and surface-acoustic-wave (SAW) vapor sensors are clarified.

216 A scalable surface-acoustic-wave- (SAW-) based cantilevered device for port

217 Piezoelectric surface acoustic waves (SAWs) are powerful for investigating and

218 It has recently been shown that surface acoustic waves (SAWs) can be piezoelectrically coupled t

219 In this device, two identical surface acoustic waves (SAWs) generated by interdigital transduc

220 Rayleigh surface acoustic waves (SAWs) have been demonstrated as a powerf

221 field-effect transistors (FETs) with surface acoustic waves (SAWs) have substantial potential, previo

222 he airborne ultrasound, generated by surface acoustic waves (SAWs) in the solid which are first refle

223 Surface acoustic waves (SAWs) offer great potential for quantum

224 i are supplied either by piezoactive surface acoustic waves (SAWs) or by microelectrode-generated ele

225 Surface acoustic waves (SAWs) propagating on piezoelectric subst

226 Surface acoustic waves (SAWs) strongly modulate the shallow elec

227 Specifically, we employ surface acoustic waves (SAWs) to drive intense chaotic streaming

228 iation forces, generated by standing surface acoustic waves (SAWs), and dielectrophoretic (DEP) force

229 man blood plasma, using ultra-high frequency acoustic wave sensing in combination with ultrathin, oli

230 The acoustic wave sensing platform is a quartz substrate fun

231 ast gas-chromatograph coupled with a surface acoustic wave sensor (UFGC-SAW) was also used to monitor

232 notube, gold nanoparticle-based, and surface acoustic wave sensor arrays.

233 Results showed that the sensitivity of the acoustic wave sensor can be improved by simply increasin

234 sing polymer-guided shear horizontal surface acoustic wave sensor platforms on 36 degrees rotated Y-c

235 s) to amplify the mass loading effect of the acoustic wave sensor to achieve a limit of detection of

236 escribe the development and evaluation of an acoustic wave sensor, the quartz crystal microbalance (Q

237 HMF determination in honey, using a low cost acoustic wave sensor.

238 ients will not provide accurate estimates of acoustic-wave sensor responses.

239 We employed a 24-channel acoustic-wave sensor system that provided previously una

240 ic transducer (i.e., pMUT and cMUT), surface acoustic wave sensors (SAW) and triboelectric nanogenera

241 an array of 6 diverse polymer-coated surface acoustic wave sensors are used to illustrate the approac

242 n integrated array of polymer-coated surface acoustic wave sensors configured and tested similarly.

243 s suggest that DNA conformation probing with acoustic wave sensors is a much more improved detection

244 ity to fabricate Love wave and other surface acoustic wave sensors using planar metallization technol

245 Surface acoustic wave sensors with acoustically thin polymer fil

246 Shear horizontal surface acoustic wave (SH-SAW) sensors are regarded as a promisi

247 The system uses shear-horizontal surface acoustic wave (SH-SAW) sensors operating directly in the

248 es this need, using shear horizontal surface acoustic wave (SH-SAW) sensors, which function effective

249 In this study, a shear horizontal surface acoustic wave (SHSAW) was used for the detection of food

250 hich accordingly built up a standing surface acoustic wave (SSAW) field across the channel.

251 n this article, we report a standing surface acoustic wave (SSAW)-based cell coculture platform.

252 e short bursts (150 mus) of standing surface acoustic waves (SSAW) triggered by an electronic feedbac

253 into multiple outputs using standing surface acoustic waves (SSAW).

254 ng inflammatory cells using standing surface acoustic waves (SSAW).

255 re selectively merged by a traveling surface acoustic wave (T-SAW) pulse.

256 We demonstrate that a narrow beam surface acoustic wave, targeted at the oil buffer, causes nearby

257 nfiguration of tilted-angle standing surface acoustic waves (taSSAW), which are oriented at an optima

258 We present a versatile surface acoustic wave technique that is capable of controlling t

259 ve agreement with those obtained via surface acoustic wave techniques.

260 cal functionalities to passive piezoelectric acoustic wave technologies could enable all-acoustic and

261 asic concepts remain the same: to produce an acoustic wave that can be focused at a specific location

262 to demonstrate a novel type of leaky-guided acoustic wave that couples simultaneously to two indepen

263 gh the piezo-electric effect, which produces acoustic waves that are routed and coupled to the optome

264 onator array, we generate localized standing acoustic waves that can be reconfigured in real-time.

265 r is used to generate high frequency surface acoustic waves that propagate through the laser-heated r

266 oiting local pressure differences created by acoustic waves that result in refractive index contrasts

267 e of control of radiation and propagation of acoustic waves thus offering new design approaches for a

268 functional characteristics by detecting the acoustic wave to construct PA images.

269 erapy (PDT) by the use of highly penetrating acoustic waves to activate a class of sound-responsive m

270 In this paper, we utilize bulk acoustic waves to control the position of microparticles

271 sent 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the captu

272 ontrol nanostructure growth is through using acoustic waves to create pressure nodes for clustering.

273 stage, it can also be accomplished by using acoustic waves to deflect the laser beam in a manner tha

274 Acousto-microfluidics uses acoustic waves to manipulate and sense particles and flu

275 g time reversal in a room to focus transient acoustic waves to the flame to extinguish it.

276 The ability of surface acoustic waves to trap and manipulate micrometer-scale p

277 an observable luminescent signal (or even an acoustic wave) to offer sensitive and selective imaging

278 e we demonstrate microwave frequency surface acoustic wave transducers co-integrated with nanophotoni

279 ngle-crystal samples of periclase (MgO) from acoustic wave travel times was measured with ultrasonic

280 The precisely measured acoustic wave travel times which were used to derive the

281 particle separation via a traveling surface acoustic wave (TSAW).

282 echanical properties using traveling surface acoustic waves (TSAWs).

283 We also show that the same acoustic waves, used to create the nanolenses, can mitig

284 frequency separation of electromagnetic and acoustic waves using graded metasurfaces.

285 h sub-microsecond switching time by exciting acoustic waves using multi-tone microwave signals.

286 e of an array of four polymer-coated surface acoustic wave vapor sensors was explored using calibrate

287 rray of eight polymer-coated 158-MHz surface acoustic wave vapor sensors were investigated.

288 ) as models of responses from polymer-coated acoustic-wave vapor sensors are critically examined.

289 The acoustic wave velocity of the material is directly recov

290 Surface acoustic waves were then used to tune light scattering a

291 i-bit is a two-state degree of freedom of an acoustic wave, which can be in a coherent superposition

292 lanche is modified by the propagation of the acoustic wave, which is then measured by the detector.

293 tion that particles can be manipulated by an acoustic wave with a wavelength that is 6 orders of magn

294 t, these ultrasonic metamaterials can convey acoustic waves with a group velocity antiparallel to pha

295 However, acoustic waves with frequency equal to marker's resonant

296 to device miniaturization needed to support acoustic waves with nanometer-scale wavelengths.

297 With nanoscale transducers, acoustic waves with sub-optical wavelengths can now be e

298 esent an X-ray microscope capable of imaging acoustic waves with subpicosecond resolution within mm-s

299 that this intrinsic limit can be broken for acoustic waves with subwavelength-structured surfaces (m

300 ovide broad insights into the interaction of acoustic waves with the structure of materials, and the