Lingnan Spirit Forever - A Mission in Transition, 1951-1990 : From the Trustees of Lingnan University to the Lingnan Foundation

Dr. AU, Tung Steven, taught at Lingnan University (Guangzhou) during 1946-47. He later became a board member of the Trustee of Lingnan University in US in 1973. Dr. AU had extensive knowledge of the historical development of Lingnan University. This publication supplemented and extended an earlier publication entitled Lingnan University : a short history based primarily on the records of the University\u27s American Trustees written by Prof. Corbett, Charles. The contents covered also the post-1952 development of Lingnan University in various occasions, including the re-establishment of Lingnan College in 1967.https://commons.ln.edu.hk/lingnan_history_bks/1029/thumbnail.jp

Bio-Hybrid Micro/Nanodevices Powered by Flagellar Motor: Challenges and Strategies

Molecular motors, which are precision-engineered by nature, offer exciting possibilities for bio-hybrid engineered systems. They could enable real applications ranging from micro/nano fluidics, to biosensing, to medical diagnoses. This review describes the fundamental biological insights and fascinating potentials of these remarkable sensing and actuation machines, in particular bacterial flagellar motors, as well as their engineering perspectives with regard to applications in bio-engineered hybrid systems and nanobiotechnology

Method of fabricating a nanochannel system for DNA sequencing and nanoparticle characterization

A process for fabricating a nanochannel system using a combination of microelectromechanical system (MEMS) microfabrication techniques, atomic force microscopy (AFM) nanolithography, and focused ion beam (FIB). The nanochannel system, fabricated on either a glass or silicon substrate, has channel heights and widths on the order of single to tens of nanometers. The channel length is in the micrometer range. The nanochannel system is equipped with embedded micro and nanoscale electrodes, positioned along the length of the nanochannel for electron tunneling based characterization of nanoscale particles in the channel. Anodic bonding is used to cap off the nanochannel with a cover chip

Magnetic microrobot and its application in a microfluidic system

AbstractThis paper researches the design and control method of a microrobot in a microfluidic system by electromagnetic field. The microrobot can move along the microchannel to a required position, and by changing the magnetic torque, the microrobot can also rotate in the microfluidic chip. As an application of the microrobot, it is used as a mobile micromixer to mix two solutions in the microfluidic chip, and the experimental results verify its effectiveness

High-frequency eddy current measurements using sensor-mounted electronics

Eddy current techniques are used widely for the detection of surface-breaking cracks in metal samples and the detection of such defects in metals with low electrical conductivity is challenging. To achieve good sensitivity to small surface cracks, the electromagnetic skin depth of the eddy current needs to be small, which often means operating at MHz frequencies. One of the major challenges in high-frequency eddy current testing is that the capacitance of the cable between the instrument electronics and the sensor head becomes significant in the MHz range, making the system unstable and introducing noise into the system as the cable moves and interacts electrically with objects close to it. There are significant benefits to locating the electrical circuitry directly behind the eddy current sensor coils, reducing issues with cable-induced electrical noise, enabling the detection of smaller defects at earlier stages of growth. Materials such as nickel-based super-alloys, titanium, austenitic steel and carbon fibre composites are often used in safety-critical applications, where the ability to detect surface cracks at the earliest possible stage is vital. Examples are presented that show the detection of small defects in a range of challenging materials at eddy current frequencies up to more than 15 MHz

A micromachined flow shear-stress sensor based on thermal transfer principles

Microhot-film shear-stress sensors have been developed by using surface micromachining techniques. The sensor consists of a suspended silicon-nitride diaphragm located on top of a vacuum-sealed cavity. A heating and heat-sensing element, made of polycrystalline silicon material, resides on top of the diaphragm. The underlying vacuum cavity greatly reduces conductive heat loss to the substrate and therefore increases the sensitivity of the sensor. Testing of the sensor has been conducted in a wind tunnel under three operation modes-constant current, constant voltage, and constant temperature. Under the constant-temperature mode, a typical shear-stress sensor exhibits a time constant of 72 μs

Method of fabricating a nanochannel system for DNA sequencing and nanoparticle characterization

A process for fabricating a nanochannel system using a combination of microelectromechanical system (MEMS) microfabrication techniques, atomic force microscopy (AFM) nanolithography, and focused ion beam (FIB). The nanochannel system, fabricated on either a glass or silicon substrate, has channel heights and widths on the order of single to tens of nanometers. The channel length is in the micrometer range. The nanochannel system is equipped with embedded micro and nanoscale electrodes, positioned along the length of the nanochannel for electron tunneling based characterization of nanoscale particles in the channel. Anodic bonding is used to cap off the nanochannel with a cover chip

Underwater shear-stress sensor

This paper reports the development of a micromachined, vacuum-cavity insulated, thermal shear-stress sensor for underwater applications. We focus on two major challenges for underwater shear-stress sensors: the waterproof coating and pressure sensitivity. It is found that thin-film CVD Parylene is a good waterproof material and sensors coated with 2 µm Parylene N can survive in water for at least one month at 55°C. It is also found that reducing the size and increasing the thickness of the sensor diaphragm are effective in minimizing the pressure sensitivity

Micro thermal shear stress sensor with and without cavity underneath

Micro hot-film shear-stress sensors have been designed and fabricated by surface micromachining technology compatible with IC technology. A poly-silicon strip, 2 µm x 80 µm, is deposited on the top of a thin silicon nitride film and functions as the sensor element. By using sacrificial-layer technique, a cavity (vacuum chamber), 200 x 200 x 2 µm^3, is placed between the silicon nitride film and silicon substrate. This cavity significantly decreases the heat loss to the substrate. For comparison purposes, a sensor structure without a cavity has also been designed and fabricated on the same chip. Theoretical analyses for the two vertical structures with and without a cavity show that the former has a lower frequency response and higher sensitivity than the latter. When the sensor is operated in constant temperature mode, the cut-off frequencies can reach 130 k-Hz and 9 k-Hz respectively for the sensors without and with cavities