نتایج جستجو برای: harmonic excitation
تعداد نتایج: 108365 فیلتر نتایج به سال:
This paper investigates the failure mechanism of Fine-pitch Ball Grid Array (FBGA) solder joints of memory modules due to harmonic excitation by the experiments and the finite element method. A finite element model of the memory module was developed, and the natural frequencies and modes were calculated and verified by experimental modal testing. Modal damping ratios are also obtained and used ...
A multifunctional device to transfer graphical or text information for blind or visually impaired is presented. The prototype using tactile perception has been designed where information displayed on the screen of electronic device (mobile phone, PC) is transferred by oscillating needle, touching the fingertip. Having the aim to define optimal parameters of the fingertip excitation by needle, t...
Second-harmonic generation (SHG) is the most specific label-free indicator of collagen accumulation in widespread pathologies such as fibrosis, and SHG-based measurements hold important potential for biomedical analyses. However, efficient collagen SHG scoring in histological slides is hampered by the limited depth-of-field of usual nonlinear microscopes relying on focused Gaussian beam excitat...
A biophotonics approach based on the nonlinear optical process of second harmonic generation is presented and demonstrated on malignant human cell lines labelled by harmonic nanoparticles. The method enables independent imaging and therapeutic action, selecting each modality by simply tuning the excitation laser wavelength from infrared to visible. In particular, the generation of deep ultravio...
The generation of the third harmonic of 150-fs 4-mJ Ti:sapphire laser pulses in the atmospheric air preliminary excited by 15-ns 100-mJ pulses of the second harmonic of a Nd:YAG laser is investigated. Preliminary laser excitation of a gas is shown to considerably increase the efficiency of frequency tripling of femtosecond pulses. Characteristic times corresponding to the maximum intensity of t...
Synopsis: The interference of attosecond electron wavepackets, created by high harmonic and femtosecond laser pulses, is measured. The first electron wavepacket is generated by direct ionization of He, and the second one by the two step process of resonant excitation by the attosecond high harmonic pulse and subsequent ionization by the laser pulse. The amplitude and phase retrieved from the in...
Squeezed states are quantum states of a harmonic oscillator in which the variance of two conjugate variables each oscillate out of phase. Ultrafast optical excitation of crystals can create squeezed phonon states, where the variance of the atomic displacements oscillates due to a sudden change in the interatomic bonding strength. With femtosecond x-ray diffraction we measure squeezing oscillati...
By radiating bifrequency primary waves from two ultrasonic emitters with changing the phases of the primary waves, we can obtain the sound fields that are different from the usual inphase excitation. Especially, for the excitation of out-phase by 180 degrees the difference frequency wave has the directivity of almost uniformity near the acoustic axis. Additionally, the sound pressure levels of ...
We calculate the cross-section for the excitation and subsequent decay of triple giant resonances (TGDR) in several nuclei excited with heavy ions. The recently developed coherent plus incoherent theory for the excitation in conjunction with the hybrid decay model of Dias-Hussein-Adhikari are used for the purpose. It is emphasized that the direct decay of the TGR is expected to deviate apprecia...
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