Building recognition on subregion’s multi-scale gist feature extraction and corresponding columns information based dimensionality reduction

Peer reviewedPublisher PD

Particle focusing and separation in xanthan gum solutions

There has been increasing interest in the use of magnetic fluids to manipulate diamagnetic particles in microfluidic devices. Focusing particles (both biological and synthetic) into a single tight stream is usually a necessary upstream operation in numerous microfluidic applications. Current methods for diamagnetic-particle focusing in magnetic fluids require either a pair of repulsive magnets or a diamagnetic sheath flow, which can work efficiently for very small particles by simply increasing the flow-rate ratio between the sheath fluid and particle suspension. This approach, however, becomes difficult to implement if particles need to be focused in both the horizontal and vertical directions for so-called three dimensional focusing. Therefore, a variety of sheathless particle-focusing approaches have been developed in microfluidic devices, which are classified as either passive or active depending on the source of the involving force. We demonstrate herein a passive, tunable, sheathless focusing of diamagnetic particles in a microchannel ferrofluid flow with a single set of overhead permanent magnets. Particles are focused into a single stream near the bottom wall of a straight rectangular microchannel, where a magnetic-field minimum is formed because of the magnetization of the ferrofluid. This focusing can be readily switched off and on by removing and replacing the permanent magnets. More importantly, the particle-focusing position can be tuned by shifting the magnets with respect to the microchannel. We perform a systematic experimental study of the parametric effects of the fluid-particle-channel system on diamagnetic particle focusing in terms of a defined particle-focusing effectiveness

Particles Focusing in Ferrofluids with Magnet

There has been increasing interest in the use of magnetic fluids to manipulate diamagnetic particles in microfluidic devices. Focusing particles (both biological and synthetic) into a single tight stream is usually a necessary upstream operation in numerous microfluidic applications. Current methods for diamagnetic-particle focusing in magnetic fluids require either a pair of repulsive magnets or a diamagnetic sheath flow, which can work efficiently for very small particles by simply increasing the flow-rate ratio between the sheath fluid and particle suspension. This approach, however, becomes difficult to implement if particles need to be focused in both the horizontal and vertical directions for so-called three dimensional focusing. Therefore, a variety of sheathless particle-focusing approaches have been developed in microfluidic devices, which are classified as either passive or active depending on the source of the involving force. We demonstrate herein a passive, tunable, sheathless focusing of diamagnetic particles in a microchannel ferrofluid flow with a single set of overhead permanent magnets. Particles are focused into a single stream near the bottom wall of a straight rectangular microchannel, where a magnetic-field minimum is formed because of the magnetization of the ferrofluid. This focusing can be readily switched off and on by removing and replacing the permanent magnets. More importantly, the particle-focusing position can be tuned by shifting the magnets with respect to the microchannel. We perform a systematic experimental study of the parametric effects of the fluid-particle-channel system on diamagnetic particle focusing in terms of a defined particle-focusing effectiveness

The Relation of Gas Seepage and Coal Body Damage Under the True Three Dimension Stress

AbstractThe law of gas flow is the basis of coal and gas outburst prevention and gas drainage rate increase. Thus the relation of gas seepage and coal body damage under the true three dimension stress is studied. The research results show that when volume stress is not change with the change of pore pressure the permeability of coal body change with the parabolic law. The relation of damage and permeability of coal body is established. It can be known that during load of coal body the greater the damage occur, the more the permeability of coal body after unload decrease than primary permeability of coal body

Dimension Reduction Using Samples’ Inner Structure Based Graph for Face Recognition

Acknowledgments This research is supported by (1) the Ph.D. Programs Foundation of Ministry of Education of China under Grant (no. 20120061110045) and (2) the Natural Science Foundation of Jilin Province of China under Grant (no. 201115022).Peer reviewedPublisher PD

Building recognition on subregion’s multi-scale gist feature extraction and corresponding columns information based dimensionality reduction

In this paper, we proposed a new building recognition method named subregion’s multiscale gist feature (SM-gist) extraction and corresponding columns information based dimensionality reduction (CCI-DR). Our proposed building recognition method is presented as a two-stage model: in the first stage, a building image is divided into 4 × 5 subregions, and gist vectors are extracted from these regions individually. Then, we combine these gist vectors into a matrix with relatively high dimensions. In the second stage, we proposed CCI-DR to project the high dimensional manifold matrix to low dimensional subspace. Compared with the previous building recognition method the advantages of our proposed method are that (1) gist features extracted by SM-gist have the ability to adapt to nonuniform illumination and that (2) CCI-DR can address the limitation of traditional dimensionality reduction methods, which convert gist matrices into vectors and thus mix the corresponding gist vectors from different feature maps. Our building recognition method is evaluated on the Sheffield buildings database, and experiments show that our method can achieve satisfactory performance

Designing a Programming Contract Library for Java

Programmers are now developing large and complex software systems, so it’s important to have software that is consistent, efficient, and robust. Programming contracts allow developers to specify preconditions, postconditions, and invariants in order to more easily identify programming errors. The design by contract principle [1] was first used in the Eiffel programming language [2], and has since been extended to libraries in many other languages. The purpose of my project is to design a programming contract library for Java. The library supports a set of preconditions, postconditions, and invariants that are specified in Java annotations. It incorporates contract checking for objects of classes following the bean notation [3]. The library also supports checking for user-defined functions as contract conditions. This feature allows the user to check for complex contract conditions. In addition to these, the library supports contracts using lambdas in Java 8 [4], which to our knowledge has not been done in previous works on Java contracts. While the results show us that enabling contracts lowers the performance of the system, especially when lambda contracts are used, we also demonstrate how careful design can significantly reduce the overhead

ELECTROKINETIC FOCUSING AND DISPENSING OF PARTICLES AND CELLS ON MICROFLUIDIC CHIPS

ABSTRACT This work investigated the electrokinetic focusing and dispensing of polystyrene particles and red blood cells on microfluidic chips. Particles or cells were first electrokinetically focused using the merging of focusing streams on the sample stream, and subsequently separated as a result of the focusing. These particles or cells were then selectively dispensed from the focused sample stream using precise application of electrical pulses. The whole process of focusing, separation and dispensing of particles was visualized by a custom-made microscopy system. In particular, the width of the focused fluorescein stream and the accelerated electrophoretic motion of particles and cells were measured in a cross-channel and compared with a proposed analytical model. The electrokinetic manipulation of particles and cells demonstrated in this work can be used for developing integrated lab-on-a-chip devices for studies of cells

An easy approach to control β-phase formation in PFO films for optimized emission properties

We demonstrate a novel approach to control β-phase content generated in poly(9,9-dioctylfluorene) (PFO) films. A very small amount of paraffin oil was used as the additive to the PFO solution in toluene. The β-phase fraction in the spin-coated PFO films can be modified from 0% to 20% simply by changing the volume percentage of paraffin oil in the mixed solution. Organic light emitting diodes (OLEDs) and amplified spontaneous emission (ASE) study confirmed low β-phase fraction promise better OLEDs device, while high β-phase fraction benefits ASE performance