There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

基礎講座 電気泳動(Electrophoresis)

Alloy negative electrodes for Li-ion batteries.

Thermophysical Properties Research Literature Retrieval Guide Edited by Y. S. Touloukian, J. K. Gerritsen and N. Y. Moore Second edition, revised and expanded. Book 1: Pp. xxi + 819. Book 2: Pp.621. Book 3: Pp. ix + 1315. (New York: Plenum Press, 1967.) n.p.

/pdf/heat-and-mass-transfer-1yaijfx8vp.pdf

Heat and Mass Transfer

https://cyberleninka.org/article/n/591413.pdf

The state of understanding of the lithium-ion-battery graphite solid electrolyte interphase (SEI) and its relationship to formation cycling

The limitation of hot spot cooling in microchips represents an important hurdle for the electronics industry to overcome with coolers yet to exceed the efficiencies required. Nanotechnology-enabled heat sinks that can be magnetophoretically formed onto the hot spots within a microfluidic environment are presented. CrO2 nanoparticles, which are dynamically chained and docked onto the hot spots, establish tuneable high-aspect-ratio nanofins for the heat exchange between these hot spots and the liquid coolant. These nanofins can also be grown and released on demand, absorbing and releasing the heat from the hot spots into the microfluidic system. It is shown that both high aspect ratio and flexibility of the fins have a dramatic effect on increasing the heat sinking efficiency. The system has the potential to offer a practical cooling solution for future electronics.

Dynamic nanofin heat sinks

Increasing the thermal conductivity of PDMS (polydimethylsiloxane) based microfluidics is an important issue for the thermal management of hot spots produced by embedding electronic circuits in such systems. This paper presents a solution for enhancing the thermal conductivity of such PDMS based microfluidics by introducing thermally conductive alumina (Al2O3) nanoparticles, forming PDMS/Al2O3 nanocomposites. The materials are fully characterized for different concentrations of Al2O3 in PDMS for experiments which are conducted at different flow rates. Our results suggest that incorporation of Al2O3 nanoparticles at 10% w/w in the PDMS based nanocomposite significantly enhances the heat conduction from hot spots by enhancing the thermal conductivity, while maintaining the flexibility and decreasing the specific heat capacity of the developed materials. This proof-of-concept study offers potential for a practical solution for the cooling of future embedded electronic systems.

PDMS nanocomposites for heat transfer enhancement in microfluidic platforms

Miniaturization of conventional energy sources has so far proven to be a cumbersome process. A recently developed concept of thermopower waves has shown tremendous potential to reduce the dimensions of power sources while maintaining their energy generation capabilities. We demonstrate a tremendous improvement in the output for these thermopower wave-based energy generation devices by implementing manganese dioxide (MnO2) as the core thermoelectric material. In this work, the thermoelectric MnO2 layer is used as a pathway for the propagation of thermopower waves that are generated as a result of an exothermic chemical reaction of a solid fuel (nitrocellulose). Such self-propagating thermopower waves result in exceptionally high voltage output on the order of 1.8 V and a specific power (power-to-mass ratio) on the order of 1.0 kW·kg–1. The output voltage is at least 300% higher than any other thermopower wave system reported so far.

MnO2-Based Thermopower Wave Sources with Exceptionally Large Output Voltages

Recently, the bubble-based systems have offered a new paradigm in microfluidics. Gas bubbles are highly flexible, controllable and barely mix with liquids, and thus can be used for the creation of reconfigurable microfluidic systems. In this work, a hydrodynamically actuated bubble-based microfluidic system is introduced. This system enables the precise movement of air bubbles via axillary feeder channels to alter the geometry of the main channel and consequently the flow characteristics of the system. Mixing of neighbouring streams is demonstrated by oscillating the bubble at desired displacements and frequencies. Flow control is achieved by pushing the bubble to partially or fully close the main channel. Patterning of suspended particles is also demonstrated by creating a large bubble along the sidewalls. Rigorous analytical and numerical calculations are presented to describe the operation of the system. The examples presented in this paper highlight the versatility of the developed bubble-based actuator for a variety of applications; thus providing a vision that can be expanded for future highly reconfigurable microfluidics.

/pdf/a-multi-functional-bubble-based-microfluidic-system-10ex1842uq.pdf

A multi-functional bubble-based microfluidic system

We present the thermal analysis of liquid containing Al2O3 nanoparticles in a microfluidic platform using an infrared camera. The small dimensions of the microchannel along with the low flow rates (less than 120 μl min−1) provide very low Reynolds numbers of less than 17.5, reflecting practical parameters for a microfluidic cooling platform. The heat analysis of nanofluids has never been investigated in such a regime, due to the deficiencies of conventional thermal measurement systems. The infrared camera allows non-contact, three dimensional and high resolution capability for temperature profiling. The system was studied at different w/w concentrations of thermally conductive Al2O3 nanoparticles and the experiments were in excellent agreement with the computational fluid dynamics (CFD) simulations.

/pdf/thermal-analysis-of-nanofluids-in-microfluidics-using-an-3k62o5nzse.pdf

Pyshar Yi

Papers

Dynamic nanofin heat sinks

PDMS nanocomposites for heat transfer enhancement in microfluidic platforms

MnO2-Based Thermopower Wave Sources with Exceptionally Large Output Voltages

A multi-functional bubble-based microfluidic system

Thermal analysis of nanofluids in microfluidics using an infrared camera.