Purcell’s swimmer was proposed by E. M. Purcell to explain bacterial swimming motions. It has been proved experimentally that a swimmer of this kind is possible under inertial-less and high viscous environment. But w...Purcell’s swimmer was proposed by E. M. Purcell to explain bacterial swimming motions. It has been proved experimentally that a swimmer of this kind is possible under inertial-less and high viscous environment. But we could not investigate all the aspects of this mechanism through experiments due to practical difficulties. The computational fluid dynamics (CFD) provides complementary methods to experimental fluid dynamics. In particular, these methods offer the means of testing theoretical advances for conditions unavailable experimentally. Using such methodology, we have investigated the fluid dynamics of force production associated with the Purcell’s swimmer. By employing dynamic mesh and user-defined functions, we have computed the transient flow around the swimmer for various stroke angles. Our simulations capture the bidirectional swimming property successfully and are in agreement with existing theoretical and experimental results. To our knowledge, this is the first CFD study which shows the fact that swimming direction depends on stroke angle. We also prove that for small flapping frequencies, swimming direction can also be altered by changing frequency-showing breakdown of Stokes law with inertia.展开更多
A nonlinear optical crystal of gamma glycine was grown by slow evaporation solution growth technique using deionized water and sodium acetate. The functional groups and vibrational frequencies were identified using FT...A nonlinear optical crystal of gamma glycine was grown by slow evaporation solution growth technique using deionized water and sodium acetate. The functional groups and vibrational frequencies were identified using FTIR spectral analysis. The cell parameters were determined from single crystal X-ray diffraction analysis. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. The optical transmittance window and lower cutoff wavelength have been identified by UV-absorption spectrum analysis. Second harmonic generation (SHG) efficiency measurement was carried out by powder Kurtz method.展开更多
Single crystals of glycine doped potassium acid phthalate (KAP) have been grown from low temperature solution growth method by employing slow evaporation of the solvent at room temperature. The grown crystal was subje...Single crystals of glycine doped potassium acid phthalate (KAP) have been grown from low temperature solution growth method by employing slow evaporation of the solvent at room temperature. The grown crystal was subjected to various studies such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV-visible and Second Harmonic Generation (SHG) studies. The thermal stability, mechanical strength and dielectric constant were also measured. The various studies revealed the influence of the glycine on KAP and the investigations indicated that glycine played an important role in the changes of the spectral, optical and mechanical properties of KAP crystals.展开更多
文摘Purcell’s swimmer was proposed by E. M. Purcell to explain bacterial swimming motions. It has been proved experimentally that a swimmer of this kind is possible under inertial-less and high viscous environment. But we could not investigate all the aspects of this mechanism through experiments due to practical difficulties. The computational fluid dynamics (CFD) provides complementary methods to experimental fluid dynamics. In particular, these methods offer the means of testing theoretical advances for conditions unavailable experimentally. Using such methodology, we have investigated the fluid dynamics of force production associated with the Purcell’s swimmer. By employing dynamic mesh and user-defined functions, we have computed the transient flow around the swimmer for various stroke angles. Our simulations capture the bidirectional swimming property successfully and are in agreement with existing theoretical and experimental results. To our knowledge, this is the first CFD study which shows the fact that swimming direction depends on stroke angle. We also prove that for small flapping frequencies, swimming direction can also be altered by changing frequency-showing breakdown of Stokes law with inertia.
文摘A nonlinear optical crystal of gamma glycine was grown by slow evaporation solution growth technique using deionized water and sodium acetate. The functional groups and vibrational frequencies were identified using FTIR spectral analysis. The cell parameters were determined from single crystal X-ray diffraction analysis. Thermogravimetric analysis (TGA) and differential thermal analysis (DTA) were used to study its thermal properties. The optical transmittance window and lower cutoff wavelength have been identified by UV-absorption spectrum analysis. Second harmonic generation (SHG) efficiency measurement was carried out by powder Kurtz method.
文摘Single crystals of glycine doped potassium acid phthalate (KAP) have been grown from low temperature solution growth method by employing slow evaporation of the solvent at room temperature. The grown crystal was subjected to various studies such as X-ray diffraction (XRD), Fourier Transform Infrared (FTIR), UV-visible and Second Harmonic Generation (SHG) studies. The thermal stability, mechanical strength and dielectric constant were also measured. The various studies revealed the influence of the glycine on KAP and the investigations indicated that glycine played an important role in the changes of the spectral, optical and mechanical properties of KAP crystals.
