Kai  Yang

Dr. Kai Yang

Smart Electronic Materials and Systems Research Group, Department of Electronics and Computer Science, University of Southampton, Southampton SO17 1BJ, UK

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 June 2013 in IET Microwaves, Antennas & Propagation
Verified
Journal Article
Open access
PDF file
ACAlford Chauraya
Alford Chauraya
William WhittowWilliam Whittow
William Whittow
JVJ(Yiannis) C. Vardaxoglou
J(Yiannis) C. Vardaxoglou
Yi LiYi Li
Yi Li
Russel  TorahRussel Torah
Russel Torah
John  TudorJohn Tudor
John Tudor
This study presents an inkjet printed textile antenna realised using a novel fabrication methodology. Conventionally, it is very difficult to inkjet print onto textiles because of surface roughness. This study demonstrates how this can be overcome by developing an interface coated layer which bonds to a standard polyester cotton fabric, creating a smooth surface. A planar dipole antenna has been fabricated, simulated and measured. This study includes DC resistance, RF reflection coefficient results and antenna radiation patterns. Efficiencies of greater than 60% have been achieved with only one layer of conducting ink. The study demonstrates that the interface layer saves considerable time and cost in terms of the number of inkjet layers needed whilst also improving the printing resolution.

12 July 2013 in Textile Research Journal
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Journal Article
Closed access
KYKai Yang
Kai Yang
Russel  TorahRussel Torah
Russel Torah
Yang WeiYang Wei
Yang Wei
Stephen BeebyStephen Beeby
Stephen Beeby
John  TudorJohn Tudor
John Tudor
Conductive textiles are fabrics that include conductive yarns woven into or conductive tracks printed on to the textiles. Conductive textiles have attracted significant attention, since they are fundamental for the integration of electronic functions to achieve wearable devices. Screen printing is a well-established and cost-effective fabrication method; it enables a versatile layout of conductive tracks. The limitation of the current screen-printed conductive textiles is low durability to weathering, abrasion and washing. This paper presents a process for producing a waterproof and durable conductive textile using only screen printing. A three functional layer design was used to fabricate the durable conductive tracks. Firstly, an interface layer was printed to provide a smooth surface for subsequent printing, under-side protection and electrical insulation. Next, a silver layer provided the conductive track and finally an encapsulation layer was printed on top to provide upper-side protection and electrical insulation. The printed silver tracks achieved maximum conductivity using a single print. The conductivity of the silver tracks returned to its original value when they were dried after soaking in water continuously for 24 hours.

1 July 2014 in Sensors and Actuators A: Physical
Verified
Journal Article
Closed access
KYKai Yang
Kai Yang
CFChris Freeman
Chris Freeman
Russel  TorahRussel Torah
Russel Torah
Stephen BeebyStephen Beeby
Stephen Beeby
John  TudorJohn Tudor
John Tudor

1 March 2017 in Nano Energy
Verified
Journal Article
Open access
AAAhmed Almusallam
Ahmed Almusallam
ZLZhenhua Luo
Zhenhua Luo
AKAbiodun Komolafe
Abiodun Komolafe
KYKai Yang
Kai Yang
ARAndrew Robinson
Andrew Robinson
Stephen BeebyStephen Beeby
Stephen Beeby
This paper details the enhancements in the dielectric and piezoelectric properties of a low-temperature screen-printable piezoelectric nano-composite film on flexible plastic and textile substrates. These enhancements involved adding silver nano particles to the nano-composite material and using an additional cold isostatic pressing (CIP) post-processing procedure. These developments have resulted in a 18% increase in the free-standing piezoelectric charge coefficient d33 to a value of 98 pC/N. The increase in the dielectric constant of the piezoelectric film has, however, resulted in a decrease in the peak output voltage of the composite film. The potential for this material to be used to harvest mechanical energy from a variety of textiles under compressive and bending forces has been evaluated theoretically and experimentally. The maximum energy density of the enhanced piezoelectric material under 800 N compressive force was found to be 34 J/m3 on a Kermel textile. The maximum energy density of the enhanced piezoelectric material under bending was found to be 14.3 J/m3 on a cotton textile. These results agree very favourably with the theoretical predictions. For a 10x10 cm piezoelectric element 100 µm thick this equates to 38 μJ and 14.3 μJ of energy generated per mechanical action respectively which is a potentially useful amount of energy

25 September 2013 in IEEE Sensors Journal
Verified
Journal Article
Closed access
GPGordon Mark Paul
Gordon Mark Paul
FCFan Cao
Fan Cao
Russel  TorahRussel Torah
Russel Torah
KYKai Yang
Kai Yang
Stephen BeebyStephen Beeby
Stephen Beeby
John  TudorJohn Tudor
John Tudor
This paper investigates a wearable approach to facial electromyography and electrooculography. The aim is to reduce discomfort and setup time in electromyographic research, rehabilitation, and computer control. A screen and stencil printed passive electrode network is fabricated on a textile headband. When this headband is worn, an array of stencil printed electrodes makes contact with the skin. The electrodes are connected to external electronics by screen printed flexible conductive tracks. The printed electrode headband is used in a facial electromyographic control system to evaluate performance. The system can be used to control a mouse cursor or simulate keyboard functions. It was found that 50 Hz noise levels in the printed textile electrodes were similar to commercial disposable electroencephalography electrodes. The effect of a wearable approach on pressure variations and motion artefact is examined. The way in which this influences the design and performance of the control system is discussed.

15 October 2019 in Sensors
Verified
Journal Article
Open access
PDF file
KYKai Yang
Kai Yang
BIBeckie Isaia
Beckie Isaia
LBLaura J.E. Brown
Laura J.E. Brown
Stephen BeebyStephen Beeby
Stephen Beeby
The ageing population has grown quickly in the last half century with increased longevity and declining birth rate. This presents challenges to health services and the wider society. This review paper considers different aspects (e.g., physical, mental, and social well-being) of healthy ageing and how health devices can help people to monitor health conditions, treat diseases and promote social interactions. Existing technologies for addressing non-physical (e.g., Alzheimer’s, loneliness) and physical (e.g., stroke, bedsores, and fall) related challenges are presented together with the drivers and constraints of using e-textiles for these applications. E-textiles provide a platform that enables unobtrusive and ubiquitous deployment of sensors and actuators for healthy ageing applications. However, constraints remain on battery, integration, data accuracy, manufacturing, durability, ethics/privacy issues, and regulations. These challenges can only effectively be met by interdisciplinary teams sharing expertise and methods, and involving end users and other key stakeholders at an early stage in the research.