scholarly journals Design and Fabrication of a Micropump With Mixing Function for LOC

2008 ◽  
Vol 2 (2) ◽  
Author(s):  
Ho-jin Kang ◽  
Bum-kyoo Choi
Keyword(s):  
Lorentz Force ◽  
High Speed ◽  
Low Voltage ◽  
Flow Direction ◽  
Ionic Current ◽  
Digital Camera ◽  
Working Medium ◽  
Electrode Length ◽  
Portable System ◽  
Phosphate Buffered Saline

A micropump, which includes a mixing function, has been fabricated. For the application to LOC (Lab On a chip), the micropump utilized PBS (Phosphate Buffered Saline) solution as the working medium. The solution is commonly used in biochemistry and cell culturing. The portable system and low energy consumption are important to realize the LOC device. In spite of a low voltage of 4V, the flow rate of the micropump was 0.02466ml∕min. The new micropump shows more enhanced performance than existing micropumps. The micropump uses Lorentz force actuation. The Lorentz force acting onto the ionic current in the PBS solution generates the fluid flow in the micropump. For the accurate prediction on flow direction, a computer simulation has been made using commercial CFD code. The results of simulation showing circulation direction were verified by experiment. The fluid circulation from each electrode combined and acted as the mixer in the micropump. The micropump was fabricated 20.2mm in length, 1mm in width and 400 μm in electrode length. To measure accurately, a high speed digital camera was used.

Investigation of the Arc of a Vacuum Circuit Breaker in a fixed Gap using the Triggering method.

2012 ◽  
Vol 13 (5) ◽  
Author(s):  
Stephen Ogidi Oodo ◽  
Huajun Dong ◽  
Jiyan Zou
Keyword(s):  
High Speed ◽  
Direct Relationship ◽  
Low Voltage ◽  
Circuit Breaker ◽  
Digital Camera ◽  
Life Time ◽  
Vacuum Arc ◽  
Ionized Gas ◽  
Metal Vapour ◽  
Vacuum Circuit Breaker

Abstract When the contacts of a Vacuum circuit breaker (VCB) with current flowing through it, is separated, an arc is generated. The Arc is usually supported by ionized gas or ionized metal vapour derived form the metal contact. This arc is an essential component of the interrupting process and capability of the Vacuum circuit breaker. The object of this paper is to trigger, record, observe and analyze the dynamic image of the Vacuum arc when it ignites in a short gap and at a low voltage. A CMOS high speed digital camera will be used to record the images of the arc. The characteristics of the arc in its diffused and constricted state, the degree of changes between the two states, and the direct relationship between the voltage and current will also be observed. The life time of the Vacuum arc will be 10ms

scholarly journals Asymmetric Ge/SiGe coupled quantum well modulators

Nanophotonics ◽  
2021 ◽  
Vol 10 (6) ◽  
pp. 1765-1773
Author(s):  
Yi Zhang ◽  
Jianfeng Gao ◽  
Senbiao Qin ◽  
Ming Cheng ◽  
Kang Wang ◽  
...  
Keyword(s):  
Energy Consumption ◽  
Quantum Well ◽  
Quantum Wells ◽  
High Speed ◽  
Low Voltage ◽  
Extinction Ratio ◽  
High Frequency Response ◽  
Modulation Format ◽  
Silicon Photonic ◽  
Coupled Quantum Well

Abstract We design and demonstrate an asymmetric Ge/SiGe coupled quantum well (CQW) waveguide modulator for both intensity and phase modulation with a low bias voltage in silicon photonic integration. The asymmetric CQWs consisting of two quantum wells with different widths are employed as the active region to enhance the electro-optical characteristics of the device by controlling the coupling of the wave functions. The fabricated device can realize 5 dB extinction ratio at 1446 nm and 1.4 × 10−3 electrorefractive index variation at 1530 nm with the associated modulation efficiency V π L π of 0.055 V cm under 1 V reverse bias. The 3 dB bandwidth for high frequency response is 27 GHz under 1 V bias and the energy consumption per bit is less than 100 fJ/bit. The proposed device offers a pathway towards a low voltage, low energy consumption, high speed and compact modulator for silicon photonic integrated devices, as well as opens possibilities for achieving advanced modulation format in a more compact and simple frame.

scholarly journals Generation of Reverse Meniscus Flow by Applying An Electromagnetic Brake

2021 ◽  
Author(s):  
Alexander Vakhrushev ◽  
Abdellah Kharicha ◽  
Ebrahim Karimi-Sibaki ◽  
Menghuai Wu ◽  
Andreas Ludwig ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Lorentz Force ◽  
Applied Magnetic Field ◽  
Numerical Study ◽  
Flow Direction ◽  
Experimental Studies ◽  
Submerged Entry Nozzle ◽  
Mean Flow ◽  
Slab Caster ◽  
The Mean

AbstractA numerical study is presented that deals with the flow in the mold of a continuous slab caster under the influence of a DC magnetic field (electromagnetic brakes (EMBrs)). The arrangement and geometry investigated here is based on a series of previous experimental studies carried out at the mini-LIMMCAST facility at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR). The magnetic field models a ruler-type EMBr and is installed in the region of the ports of the submerged entry nozzle (SEN). The current article considers magnet field strengths up to 441 mT, corresponding to a Hartmann number of about 600, and takes the electrical conductivity of the solidified shell into account. The numerical model of the turbulent flow under the applied magnetic field is implemented using the open-source CFD package OpenFOAM®. Our numerical results reveal that a growing magnitude of the applied magnetic field may cause a reversal of the flow direction at the meniscus surface, which is related the formation of a “multiroll” flow pattern in the mold. This phenomenon can be explained as a classical magnetohydrodynamics (MHD) effect: (1) the closure of the induced electric current results not primarily in a braking Lorentz force inside the jet but in an acceleration in regions of previously weak velocities, which initiates the formation of an opposite vortex (OV) close to the mean jet; (2) this vortex develops in size at the expense of the main vortex until it reaches the meniscus surface, where it becomes clearly visible. We also show that an acceleration of the meniscus flow must be expected when the applied magnetic field is smaller than a critical value. This acceleration is due to the transfer of kinetic energy from smaller turbulent structures into the mean flow. A further increase in the EMBr intensity leads to the expected damping of the mean flow and, consequently, to a reduction in the size of the upper roll. These investigations show that the Lorentz force cannot be reduced to a simple damping effect; depending on the field strength, its action is found to be topologically complex.

scholarly journals Reliability-Oriented Design of Inverter-Fed Low-Voltage Electrical Machines: Potential Solutions

Energies ◽  
2021 ◽  
Vol 14 (14) ◽  
pp. 4144
Author(s):  
Yatai Ji ◽  
Paolo Giangrande ◽  
Vincenzo Madonna ◽  
Weiduo Zhao ◽  
Michael Galea
Keyword(s):  
Power Density ◽  
High Speed ◽  
High Performance ◽  
Low Voltage ◽  
Electrical Machines ◽  
Design Stage ◽  
Switching Frequency ◽  
Special Focus ◽  
Electrical Machine ◽  
Engineering Approach

Transportation electrification has kept pushing low-voltage inverter-fed electrical machines to reach a higher power density while guaranteeing appropriate reliability levels. Methods commonly adopted to boost power density (i.e., higher current density, faster switching frequency for high speed, and higher DC link voltage) will unavoidably increase the stress to the insulation system which leads to a decrease in reliability. Thus, a trade-off is required between power density and reliability during the machine design. Currently, it is a challenging task to evaluate reliability during the design stage and the over-engineering approach is applied. To solve this problem, physics of failure (POF) is introduced and its feasibility for electrical machine (EM) design is discussed through reviewing past work on insulation investigation. Then the special focus is given to partial discharge (PD) whose occurrence means the end-of-life of low-voltage EMs. The PD-free design methodology based on understanding the physics of PD is presented to substitute the over-engineering approach. Finally, a comprehensive reliability-oriented design (ROD) approach adopting POF and PD-free design strategy is given as a potential solution for reliable and high-performance inverter-fed low-voltage EM design.

scholarly journals Advanced Electrode Design for Low-Voltage High-Speed Thin-Film Lithium Niobate Modulators

2021 ◽  
Vol 13 (2) ◽  
pp. 1-9
Author(s):  
Xingrui Huang ◽  
Yang Liu ◽  
Zezheng Li ◽  
Huan Guan ◽  
Qingquan Wei ◽  
...  
Keyword(s):  
Thin Film ◽  
Lithium Niobate ◽  
High Speed ◽  
Low Voltage ◽  
Electrode Design

scholarly journals Investigation of PVT-Aware STT-MRAM Sensing Circuits for Low-VDD Scenario

Micromachines ◽  
2021 ◽  
Vol 12 (5) ◽  
pp. 551
Author(s):  
Zhongjian Bian ◽  
Xiaofeng Hong ◽  
Yanan Guo ◽  
Lirida Naviner ◽  
Wei Ge ◽  
...  
Keyword(s):  
Nonvolatile Memory ◽  
High Speed ◽  
Low Voltage ◽  
Supply Voltage ◽  
Random Access ◽  
Magnetic Tunnel Junction ◽  
Complementary Metal Oxide Semiconductor ◽  
Current Mode ◽  
Cmos Technology ◽  
Oxide Semiconductor

Spintronic based embedded magnetic random access memory (eMRAM) is becoming a foundry validated solution for the next-generation nonvolatile memory applications. The hybrid complementary metal-oxide-semiconductor (CMOS)/magnetic tunnel junction (MTJ) integration has been selected as a proper candidate for energy harvesting, area-constraint and energy-efficiency Internet of Things (IoT) systems-on-chips. Multi-VDD (low supply voltage) techniques were adopted to minimize energy dissipation in MRAM, at the cost of reduced writing/sensing speed and margin. Meanwhile, yield can be severely affected due to variations in process parameters. In this work, we conduct a thorough analysis of MRAM sensing margin and yield. We propose a current-mode sensing amplifier (CSA) named 1D high-sensing 1D margin, high 1D speed and 1D stability (HMSS-SA) with reconfigured reference path and pre-charge transistor. Process-voltage-temperature (PVT) aware analysis is performed based on an MTJ compact model and an industrial 28 nm CMOS technology, explicitly considering low-voltage (0.7 V), low tunneling magnetoresistance (TMR) (50%) and high temperature (85 °C) scenario as the worst sensing case. A case study takes a brief look at sensing circuits, which is applied to in-memory bit-wise computing. Simulation results indicate that the proposed high-sensing margin, high speed and stability sensing-sensing amplifier (HMSS-SA) achieves remarkable performance up to 2.5 GHz sensing frequency. At 0.65 V supply voltage, it can achieve 1 GHz operation frequency with only 0.3% failure rate.

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