scholarly journals Three dimensional acoustic tweezers with acoustic vortex streaming

2021 ◽  
Author(s):  
Junfei Li ◽  
Alexandru Crivoi ◽  
Xiuyuan Peng ◽  
Lu Shen ◽  
Yunjiao Pu ◽  
...  
Keyword(s):  
Acoustic Streaming ◽  
Three Dimensional ◽  
Radiation Force ◽  
Two Dimensions ◽  
Single Beam ◽  
Scale Particle ◽  
Acoustic Tweezers ◽  
Third Dimension ◽  
Contact Free ◽  
Micrometer Scale

Abstract Acoustic tweezers use ultrasound for contact-free manipulation of particles from millimeter to sub-micrometer scale. Particle trapping originated in either radiation forces or acoustic streaming fields. Acoustic tweezers based on single-beam focused acoustic vortices have attracted considerable attention due to their selective trapping capability, but have proven difficult to use for 3D trapping without a complex transducer array and significant constraints on the trapped particle properties. Here we demonstrate the first 3D acoustic tweezer that uses a single transducer and combines the radiation force for trapping in two dimensions with the streaming force to provide levitation in the third dimension. The idea is demonstrated in both simulation and experiments, and the achieved levitation force reaches three orders of magnitude larger than for previous 3D trapping. This hybrid acoustic tweezer that integrates acoustic streaming adds a new twist to the approach and expands the range of particles that can be manipulated.

scholarly journals Three dimensional acoustic tweezers with vortex streaming

2021 ◽  
Vol 4 (1) ◽  
Author(s):  
Junfei Li ◽  
Alexandru Crivoi ◽  
Xiuyuan Peng ◽  
Lu Shen ◽  
Yunjiao Pu ◽  
...  
Keyword(s):  
Acoustic Streaming ◽  
Three Dimensional ◽  
Radiation Force ◽  
Two Dimensions ◽  
Single Beam ◽  
Scale Particle ◽  
Acoustic Tweezers ◽  
Third Dimension ◽  
Contact Free ◽  
Micrometer Scale

AbstractAcoustic tweezers use ultrasound for contact-free manipulation of particles from millimeter to sub-micrometer scale. Particle trapping is usually associated with either radiation forces or acoustic streaming fields. Acoustic tweezers based on single-beam focused acoustic vortices have attracted considerable attention due to their selective trapping capability, but have proven difficult to use for three-dimensional (3D) trapping without a complex transducer array and significant constraints on the trapped particle properties. Here we demonstrate a 3D acoustic tweezer in fluids that uses a single transducer and combines the radiation force for trapping in two dimensions with the streaming force to provide levitation in the third dimension. The idea is demonstrated in both simulation and experiments operating at 500 kHz, and the achieved levitation force reaches three orders of magnitude larger than for previous 3D trapping. This hybrid acoustic tweezer that integrates acoustic streaming adds an additional twist to the approach and expands the range of particles that can be manipulated.

scholarly journals Three-dimensional manipulation of single cells using surface acoustic waves

2016 ◽  
Vol 113 (6) ◽  
pp. 1522-1527 ◽  
Author(s):  
Feng Guo ◽  
Zhangming Mao ◽  
Yuchao Chen ◽  
Zhiwei Xie ◽  
James P. Lata ◽  
...  
Keyword(s):  
Acoustic Waves ◽  
Single Cells ◽  
Surface Acoustic Waves ◽  
Three Dimensional ◽  
Biological Cells ◽  
Acoustic Vibrations ◽  
Label Free ◽  
Acoustic Tweezers ◽  
Contact Free ◽  
Micrometer Scale

The ability of surface acoustic waves to trap and manipulate micrometer-scale particles and biological cells has led to many applications involving “acoustic tweezers” in biology, chemistry, engineering, and medicine. Here, we present 3D acoustic tweezers, which use surface acoustic waves to create 3D trapping nodes for the capture and manipulation of microparticles and cells along three mutually orthogonal axes. In this method, we use standing-wave phase shifts to move particles or cells in-plane, whereas the amplitude of acoustic vibrations is used to control particle motion along an orthogonal plane. We demonstrate, through controlled experiments guided by simulations, how acoustic vibrations result in micromanipulations in a microfluidic chamber by invoking physical principles that underlie the formation and regulation of complex, volumetric trapping nodes of particles and biological cells. We further show how 3D acoustic tweezers can be used to pick up, translate, and print single cells and cell assemblies to create 2D and 3D structures in a precise, noninvasive, label-free, and contact-free manner.

scholarly journals Acoustohydrodynamic tweezers via spatial arrangement of streaming vortices

2021 ◽  
Vol 7 (2) ◽  
pp. eabc7885
Author(s):  
Haodong Zhu ◽  
Peiran Zhang ◽  
Zhanwei Zhong ◽  
Jianping Xia ◽  
Joseph Rich ◽  
...  
Keyword(s):  
Acoustic Radiation ◽  
Acoustic Streaming ◽  
Three Dimensional ◽  
High Sensitivity ◽  
Spatial Arrangement ◽  
Label Free ◽  
Droplet Transport ◽  
Dimensional Boundary ◽  
Acoustic Tweezers ◽  
Contact Free

Acoustics-based tweezers provide a unique toolset for contactless, label-free, and precise manipulation of bioparticles and bioanalytes. Most acoustic tweezers rely on acoustic radiation forces; however, the accompanying acoustic streaming often generates unpredictable effects due to its nonlinear nature and high sensitivity to the three-dimensional boundary conditions. Here, we demonstrate acoustohydrodynamic tweezers, which generate stable, symmetric pairs of vortices to create hydrodynamic traps for object manipulation. These stable vortices enable predictable control of a flow field, which translates into controlled motion of droplets or particles on the operating surface. We built a programmable droplet-handling platform to demonstrate the basic functions of planar-omnidirectional droplet transport, merging droplets, and in situ mixing via a sequential cascade of biochemical reactions. Our acoustohydrodynamic tweezers enables improved control of acoustic streaming and demonstrates a previously unidentified method for contact-free manipulation of bioanalytes and digitalized liquid handling based on a compact and scalable functional unit.

Theory of Electron Diffraction by Crystals

1967 ◽  
Vol 22 (4) ◽  
pp. 422-431 ◽  
Author(s):  
Kyozaburo Kambe
Keyword(s):  
Integral Equation ◽  
Electron Diffraction ◽  
General Theory ◽  
Green’S Function ◽  
Green's Function ◽  
Scattering Problem ◽  
Three Dimensional ◽  
Two Dimensions ◽  
The Third ◽  
Third Dimension

A general theory of electron diffraction by crystals is developed. The crystals are assumed to be infinitely extended in two dimensions and finite in the third dimension. For the scattering problem by this structure two-dimensionally expanded forms of GREEN’S function and integral equation are at first derived, and combined in single three-dimensional forms. EWALD’S method is applied to sum up the series for GREEN’S function.

Contextualizing Multiculturalism: A Three Dimensional Examination of Multicultural Claims

2007 ◽  
Vol 1 (1) ◽  
pp. 309-353 ◽  
Author(s):  
Gila Stopler
Keyword(s):  
Political Participation ◽  
Three Dimensional ◽  
Orthodox Jews ◽  
Two Dimensions ◽  
National Minorities ◽  
Cultural Minorities ◽  
Third Dimension ◽  
The Right ◽  
Nancy Fraser ◽  
Multicultural Theory

The emergence of multicultural theory and of claims of recognition by cultural, ethnic, and national minorities has brought to the forefront previously neglected aspects of the right to equality. However, when judged on their own, claims for recognition stand the risk of failing to fully capture, and even distorting, the meaning of equality. I suggest that in order to avoid this risk, multicultural claims need to be contextualized. Employing Nancy Fraser’s framework of two dimensions of justice—recognition and redistribution—and adding a third dimension—political participation, I suggest a framework for a contextualized assessment of multicultural claims that allows us to properly and fully assess their validity. I then go on to employ this framework on the claims of Israel’s two most significant cultural minorities—the Palestinian Arabs and the Ultra Orthodox Jews. I show how the use of the suggested framework helps to expose the considerable differences between these two cultural minorities, and consequently the notable difference in the merits of their claims, a difference that would have otherwise gone undetected.

People Planning by a Fixed Resource Method

1972 ◽  
Vol 34 (3) ◽  
pp. 799-806 ◽  
Author(s):  
John C. Baird ◽  
Virgil Graf ◽  
Richard Degerman
Keyword(s):  
Cluster Analysis ◽  
Outer Space ◽  
Three Dimensional ◽  
Two Dimensions ◽  
The Third ◽  
Complex Stimuli ◽  
The Mean ◽  
Highly Correlated ◽  
Third Dimension ◽  
The Ideal

Results are presented from a new method to determine a person's conception of complex stimuli. In three related experiments Ss expressed their views of ideal organisms by distributing a fixed resource among hypothetical properties of the ideal. The results from the experiments were highly correlated, lending weight to the reliability and generality of the approach. Cluster analysis and multidimensional scaling were used to group the properties in two dimensions, while the mean amount allocated to a property was represented in the third dimension. A three-dimensional plot was constructed for each of four ideals: the only organism on earth, a member of the only species on earth, an organism going into outer space, and an organism coming to earth from outer space.

scholarly journals Responsiveness and Renewal in Canada's Community Colleges: A Study of Change in Organizations

1989 ◽  
Vol 19 (2) ◽  
Author(s):  
John S. Levin ◽  
John D. Dennison
Keyword(s):  
Community Colleges ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Developmental Models ◽  
Managing Change ◽  
The Matrix ◽  
Fiscal Support ◽  
Internal Forces ◽  
Third Dimension ◽  
The 1960S

This study deals with change in organizations. Specifically, the focus is upon Canada's community colleges during a period of economic and socio-political change in the 1980s. Canadian colleges, born and nurtured within an unprecedented era of postsecondary educational expansion in the 1960s, were founded upon ideals of democratization of opportunity, accessibility, adaptability, and comprehensiveness. This study examines if and to what extent the colleges have retained these principles in confronting external and internal forces during the last decade. The theoretical model designed for the study involved a three-dimensional matrix in which theories of adaptation (Cameron, 1984) and power, (Mintzberg, 1979) form two dimensions. The third dimension is created from a variety of optional developmental models specific to the community college as an organization (McCartan, 1983; Cross, 1985; Dennison and Gallagher, 1986). The results of the study revealed that much of the idealism and innovation which guided the colleges in earlier days was still to be found. However, in attempting to deal with increased direction from government, and from reduced fiscal support, the colleges have sought several ways to adjust or adapt. In doing so they have become more enterpreneurial, less community-oriented, and more tightly managed. Diversity, however, was also evident, as adaptive strategies differed widely in various regions across Canada. By applying the matrix designed for the study, it was possible to determine that colleges were managing change by utilizing a variety of techniques. Change in community colleges involves a diversity of methods and produces a diversity of results.

scholarly journals Measurement of the acoustic streaming pattern in a standing surface acoustic wave field

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Sebastian Sachs ◽  
Christian Cierpka ◽  
Jörg König
Keyword(s):  
Wave Field ◽  
Acoustic Waves ◽  
Acoustic Radiation ◽  
Electrical Power ◽  
Surface Acoustic Waves ◽  
Acoustic Streaming ◽  
Fluid Motion ◽  
Three Dimensional ◽  
Radiation Force ◽  
Flow Measurements

The application of standing surface acoustic waves (sSAW) has enabled the development of many flexible and easily scalable concepts for the fractionation of particle solutions in the field of microfluidic lab-ona-chip devices. In this context, the acoustic radiation force (ARF) is often employed for the targeted manipulation of particle trajectories, whereas acoustically induced flows complicate efficient fractionation in many systems [Sehgal and Kirby (2017)]. Therefore, a characterization of the superimposed fluid motion is essential for the design of such devices. The present work focuses on a structural analysis of the acousticallyexcited flow, both in the center and in the outer regions of the standing wave field. For this, experimental flow measurements were conducted using astigmatism particle tracking velocimetry (APTV) [Cierpka et al. (2010)]. Through multiple approaches, we address the specific challenges for reliable velocity measurements in sSAW due to limited optical access, the influence of the ARF on particle motion, and regions of particle depletion caused by multiple pressure nodes along the channel width and height. Variations in frequency, channel geometry, and electrical power allow for conclusions to be drawn on the formation of a complex, three-dimensional vortex structure at the beginning and end of the sSAW.

Developing a Better Understanding of the Engineer's Creative Role in Design

2002 ◽  
Vol 17 (2-3) ◽  
pp. 129-133
Author(s):  
Bill Addis
Keyword(s):  
Three Dimensional ◽  
Two Dimensions ◽  
Three Dimensions ◽  
Space Structures ◽  
The Third ◽  
Structural Problems ◽  
The World ◽  
Third Dimension ◽  
Dimension Space ◽  
Creative Role

Both architects and engineers are unconsciously drawn towards the two dimensional world – the ubiquity of the plan and elevation, and the ease of analysing 2-D structures. Yet the best architecture always exploits the three dimensional world, and the majority of structural problems and collapses occur when engineers have failed to think in the third dimension. Space structures offer an ideal learning environment for students of both architecture and engineering. They stimulate and challenge both the imagination and the intellect by forcing students out of the cosy, and often dull familiarity of two dimensions. They encourage students to conceive structures in three dimensions and drop down to two when necessary or convenient, rather than the other way round. In a world where form and forces so strongly interact, space structures force architects to step into the world of statics, and engineers into the world of geometry. An important result is a better understanding, for both architects and engineers, of the role engineers can play in helping create imaginative and practical structures.

scholarly journals Rapid three dimensional two photon neural population scanning

2015 ◽  
Author(s):  
Renaud Schuck ◽  
Peter Quicke ◽  
Caroline Copeland ◽  
Stefania Garasto ◽  
Luca A Annecchino ◽  
...  
Keyword(s):  
Laser Scanning ◽  
Neural Circuits ◽  
Three Dimensional ◽  
Two Dimensions ◽  
Laser Scanning Microscopy ◽  
Neural Population ◽  
Two Photon ◽  
Third Dimension ◽  
Scanning Strategies ◽  
Tunable Lenses

Recording the activity of neural populations at high sampling rates is a fundamental requirement for understanding computation in neural circuits. Two photon microscopy provides one promising approach towards this. However, neural circuits are three dimensional, and functional imaging in two dimensions fails to capture the 3D nature of neural dynamics. Electrically tunable lenses (ETLs) provide a simple and cheap method to extend laser scanning microscopy into the relatively unexploited third dimension. We have therefore incorporated them into our Adaptive Spiral Scanning (SSA) algorithm, which calculates kinematically efficient scanning strategies using radially modulated spiral paths. We characterised the response of the ETL, incorporated its dynamics using MATLAB models of the SSA algorithm and tested the models on populations of Izhikevich neurons of varying size and density. From this, we show that our algorithms can theoretically at least achieve sampling rates of 36.2 Hz compared to 21.6 Hz previously reported for 3D scanning techniques.

Sign in / Sign up

Export Citation Format

Share Document