Adiabatic Compression of Soliton Matter Waves

The evolution of atomic solitary waves in Bose-Einstein condensate (BEC) under adiabatic changes of the atomic scattering length is investigated. The variations of amplitude, width, and velocity of soliton are found for both spatial and time adiabatic variations. The possibility to use these variations to compress solitons up to very high local matter densities is shown both in absence and in presence of a parabolic confining potential.Comment: to appear in J.Phys.

Size effects on dynamics of nanodroplets in binary head-on collisions

Head-on collision dynamics of 10, 50 and 100 nm droplets are investigated in vacuum by molecular dynamics, involving 35,858, 4,506,410 and 36,051,466 molecules, respectively. A variety of droplet collision dynamics are observed, such as coalescence, hole formation and shattering, as a function of the Weber number. It is found for the first time that the collision and reflexive separation can occur in the nanodroplet regime when the droplet diameter reaches 100 nm but not for 10 or 50 nm droplets. The size effect in droplet collisions is studied based on the analysis of stretching factors, energy dissipation and collision outcomes for droplets of different diameters. The kinetic energy dissipation due to the atomic interactions at nanoscales is identified to significantly influence the occurrence or otherwise of reflexive separation. Through quantitative analysis of the evolution of the internal structure of the 100 nm nanodroplets collision at the Weber number of 277, it is revealed for the first time that molecules from both parent nanodroplets have penetrated the full length of the merged nanodroplet in the direction of collision, due to a combination of molecular mixing and internal currents. Consequently, all three child nanodroplets have molecules from both parent nanodroplets, contrary to the perception gained from common imaging techniques. The results show that the dynamics, outcomes and mechanisms of nanodroplet collisions have both similarities and differences compared with their micro- and macro-counterparts

Simulation of indoor harmful gas dispersion and airflow using three-dimensional lattice Boltzmann method based large-eddy simulation

ABSTRACT The lattice Boltzmann method (LBM) and large-eddy simulation (LES) are combined with a scalar subgrid-scale model to simulate the indoor air velocity field and harmful gas dispersion. The LBM-LES model is validated by comparing its results with published experimental and numerical simulation results. Taking a simplified chemical building as the scenario, the relative ventilation efficiency is evaluated based on the maximum harmful gas concentration, and configurations with centralized and distributed harmful gas sources with both mixing ventilation (MV) and displacement ventilation (DV) systems are considered. According to the results, if the density of the harmful gas is less than the air density, the DV system is more efficient than the MV system. The DV system is more stable than the MV system under fluctuating relative ventilation efficiency due to changes in the distance between the ventilation vents and in the distance between the centralized gas sources and the exhaust air vent

Paediatric Over-the-Counter (OTC) Oral Liquids Can Soften and Erode Enamel

published_or_final_versio

Optical characteristics of GAN/SI micro-pixel light-emitting diode arrays

Two-dimensional arrays of emissive micro-light-emitting diodes (μ-LEDS) have been developed for a variety of applications such as high resolution micro-displays, maskless photo-lithography and multichannel visible-light optical communications amongst others. μ-LEDs have traditionally been fabricated on InGaN LED wafers grown on transparent sapphire substrates, and have suffered from optical crosstalk issues. When a single pixel is addressed, adjacent pixels and regions appear illuminated simultaneously. Such problems could result in functional failure in high-density μ-LED applications, including reduced resolution of micro-display and decreased signal-to-noise ratio in ...postprin

High sensitivity cymbal-based accelerometer

Author name used in this publication: Cheng-Liang SunAuthor name used in this publication: K. H. LamAuthor name used in this publication: S. H. ChoyAuthor name used in this publication: H. L. W. ChanAuthor name used in this publication: X.-Z. ZhaoAuthor name used in this publication: C. L. Choy2005-2006 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

A lead-free piezoelectric transformer in radial vibration modes

Author name used in this publication: D. M. LinAuthor name used in this publication: K. H. LamAuthor name used in this publication: S. WangAuthor name used in this publication: X. Z. Zhao2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

A study on the disk-shaped piezoelectric transformer with multiple outputs

Author name used in this publication: K. H. LamAuthor name used in this publication: S. WangAuthor name used in this publication: K. W. KwokAuthor name used in this publication: X. Z. Zhao2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Ultrasonic particle trapping in microfluidic devices using soft lithography

2007-2008 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Fabrication and characterization of Ni/P(VDF-TrFE) nanoscaled coaxial cables

Author name used in this publication: Kwo Ho LamAuthor name used in this publication: Cheng-Liang SunAuthor name used in this publication: Helen Lai Wa Chan2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe