Fast acoustic tweezers for the two-dimensional manipulation of individual particles in microfluidic channels

This paper presents a microfluidic device that implements standing surface acoustic waves in order to handle single cells, droplets, and generally particles. The particles are moved in a very controlled manner by the two-dimensional drifting of a standing wave array, using a slight frequency modulation of two ultrasound emitters around their resonance. These acoustic tweezers allow any type of motion at velocities up to few 10mm/s, while the device transparency is adapted for optical studies. The possibility of automation provides a critical step in the development of lab-on-a-chip cell sorters and it should find applications in biology, chemistry, and engineering domains

Decrypting the cyclotron effect in graphite using Kerr rotation spectroscopy

We measure the far-infrared magneto-optical Kerr rotation and reflectivity spectra in graphite and achieve a highly accurate unified microscopic description of all data in a broad range of magnetic fields by taking rigorously the c-axis band dispersion and the trigonal warping into account. We find that the second- and the forth-order cyclotron harmonics are optically almost as strong as the fundamental resonance even at high fields. They must play, therefore, a major role in magneto-optical and magneto-plasmonic applications based on Bernal stacked graphite and multilayer graphene.Comment: 4 pages, 3 figures + Supplemental Materia

Analysis of interior noise ground and flight test data for advanced turboprop aircraft applications

Interior noise ground tests conducted on a DC-9 aircraft test section are described. The objectives were to study ground test and analysis techniques for evaluating the effectiveness of interior noise control treatments for advanced turboprop aircraft, and to study the sensitivity of the ground test results to changes in various test conditions. Noise and vibration measurements were conducted under simulated advanced turboprop excitation, for two interior noise control treatment configurations. These ground measurement results were compared with results of earlier UHB (Ultra High Bypass) Demonstrator flight tests with comparable interior treatment configurations. The Demonstrator is an MD-80 test aircraft with the left JT8D engine replaced with a prototype UHB advanced turboprop engine

Sustainable Growth and Ethics: a Study of Business Ethics in Vietnam Between Business Students and Working Adults

Sustainable growth is not only the ultimate goal of business corporations but also the primary target of local governments as well as regional and global economies. One of the cornerstones of sustainable growth is ethics. An ethical organizational culture provides support to achieve sustainable growth. Ethical leaders and employees have great potential for positive influence on decisions and behaviors that lead to sustainability. Ethical behavior, therefore, is expected of everyone in the modern workplace. As a result, companies devote many resources and training programs to make sure their employees live according to the high ethical standards. This study provides an analysis of Vietnamese business students’ level of ethical maturity based on gender, education, work experience, and ethics training. The results of data from 260 business students compared with 704 working adults in Vietnam demonstrate that students have a significantly higher level of ethical maturity. Furthermore, gender and work experience are significant factors in ethical maturity. While more educated respondents and those who had completed an ethics course did have a higher level of ethical maturity, the results were not statistically significant. Analysis of the results along with suggestions and implications are provided

Micro-Brillouin spectroscopy mapping of the residual density field induced by Vickers indentation in a soda-lime silicate glass

High-resolution Brillouin scattering is used to achieve 3-dimensional maps of the longitudinal acoustic mode frequency shift in soda-lime silicate glasses subject to Vickers indentations. Assuming that residual stress-induced effects are simply proportional to density changes, residual densification fields are obtained. The density gradient is nearly isotropic, confirming earlier optical observations made on a similar glass. The results show that Brillouin micro-spectroscopy opens the way to a fully quantitative comparison of experimental data with predictions of mechanical models for the identification of a constitutive law.Comment: 4 pages, 3 figures, revised version, to appear in Appl. Phys. Let