Stella W. Pang

Prof. Stella W. Pang

1. Department of Electrical Engineering, City University of Hong Kong, Hong Kong, China
+1
orcid

Research Focus & Metrics

Academic Career Length

45Years (1982-Present)

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

Representative Publications

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1 May 2007 in Experimental Cell Research
Verified
Journal Article
Closed access
EYEvelyn Yim
Evelyn Yim
Stella W. PangStella W. Pang
Stella W. Pang
KLKam W Leong
Kam W Leong

1 September 2005 in Biomaterials
Verified
Journal Article
Closed access
EYEvelyn Yim
Evelyn Yim
RRRon M. Reano
Ron M. Reano
Stella W. PangStella W. Pang
Stella W. Pang
AYAlbert F. Yee
Albert F. Yee
CCChristopher S. Chen
Christopher S. Chen
KLKam W Leong
Kam W Leong

10 August 2005 in Lab on a Chip
Verified
Journal Article
Closed access
PDF file
CLChia-Jung Lu
Chia-Jung Lu
WSWilliam H. Steinecker
William H. Steinecker
WTWei-Cheng Tian
Wei-Cheng Tian
MOMichael C. Oborny
Michael C. Oborny
JNJamie M. Nichols
Jamie M. Nichols
EZEdward Zellers
Edward Zellers
The fabrication, assembly, and initial testing of a hybrid microfabricated gas chromatograph (µGC) is described. The µGC incorporates capabilities for on-board calibration, sample preconcentration and focused thermal desorption, temperature-programmed separations, and “spectral” detection with an integrated array of microsensors, and is designed for rapid determinations of complex mixtures of environmental contaminants at trace concentrations. Ambient air is used as the carrier gas to avoid the need for on-board gas supplies. The microsystem is plumbed through an etched-Si/glass microfluidic interconnection substrate with fused silica capillaries and employs a miniature commercial pump and valve subsystem for directing sample flow. The latest performance data on each system component are presented followed by first analytical results from the working microsystem. Tradeoffs in system performance as a function of volumetric flow rate are explored. The determination of an 11-vapor mixture of typical indoor air contaminants in less than 90 s is demonstrated with projected detection limits in the low part-per-billion concentration range for a preconcentrated air-sample volume of 0.25 L.

1 November 2002 in Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena
Verified
Journal Article
Closed access
PDF file
LBL.-R. Bao
L.-R. Bao
XCXing Cheng
Xing Cheng
XHX. D. Huang
X. D. Huang
LGL. J. Guo
L. J. Guo
Stella W. PangStella W. Pang
Stella W. Pang
AYA. F. Yee
A. F. Yee
We have developed a simple imprinting technique that allows patterning over a nonflat substrate without the need for planarization. In this process, a polymer film is spin coated onto the mold and then transferred to a patterned substrate by imprinting. By selecting polymers with different mechanical properties, either suspended structures over wide gaps or supported patterns on raised features of the substrate can be obtained with high uniformity. It is found that imprinting at a temperature well above the glass transition temperature (Tg) of the polymer causes the thin residue film between features to dewet from the mold, which can greatly simplify the subsequent pattern transfer process. Multilayer three-dimensional polymer structures have also been successfully fabricated using this new imprinting method. The yield and dimensional stability in the multilayer structure can both be improved when polymers with progressively lower Tg are used for different layers. Compared to existing techniques for patterning on nonflat substrates, the current method has a number of advantages, including simplicity, versatility, high resolution, and low pattern distortion.

1 November 2002 in Journal of Vacuum Science & Technology B: Microelectronics and Nanometer Structures Processing, Measurement, and Phenomena
Verified
Journal Article
Closed access
PDF file
XHX. D. Huang
X. D. Huang
LBL.-R. Bao
L.-R. Bao
XCXing Cheng
Xing Cheng
LGL. J. Guo
L. J. Guo
Stella W. PangStella W. Pang
Stella W. Pang
AYA. F. Yee
A. F. Yee
A reversal imprinting technique was developed in this study. A polymer layer was first spin coated on a patterned hard mold, and then transferred to a substrate under an elevated temperature and pressure. The reversal imprinting method offers an advantage over conventional nanoimprinting by allowing imprinting onto substrates that cannot be easily spin coated, such as flexible polymer substrates. Another unique feature of reversal imprinting is that three different pattern-transfer modes can be achieved by controlling the degree of surface planarization of the mold after spin coating the polymer resist as well as the imprinting temperature. “Embossing” occurs at temperatures well above the glass transition temperature (Tg) of a polymer; “inking” occurs at temperatures around Tg with nonplanarized polymer coating surface on the mold; and “whole-layer transfer” occurs at temperatures around Tg but with a somewhat planarized surface. These three imprinting modes have been quantitatively correlated with the surface planarization of the mold after polymer coating and the imprinting temperature.

6 June 2005 in Journal of Microelectromechanical Systems
Verified
Journal Article
Closed access
WTWei-Cheng Tian
Wei-Cheng Tian
HCH.K.L. Chan
H.K.L. Chan
CLChia-Jung Lu
Chia-Jung Lu
Stella W. PangStella W. Pang
Stella W. Pang
EZE.T. Zellers
E.T. Zellers
The design, fabrication, and characterization of a multiple-stage Si microfabricated preconcentrator-focuser (/spl mu/PCF) for a micro gas chromatography (/spl mu/GC) system that can provide real-time quantification and identification of complex organic vapor mixtures are presented. The /spl mu/PCF consists of a Si microheater loaded with Carbopack B, Carbopack X, and Carboxen 1000 carbon adsorbent granules, and a Si micromachined cover plate. Deep reactive ion etching is utilized to produce mechanically robust fluidic interconnection adapters hermetically sealed to fused silica capillary tubing for connection to the other components in the /spl mu/GC. This three-stage device is designed to capture compounds spanning up to 4 orders of magnitude in volatility. The dead volume, thermal mass, heating efficiency, and pressure drop of the three-stage /spl mu/PCF are improved significantly over its single-stage /spl mu/PCF predecessor. We demonstrate the successful capture, desorption, and high-resolution chromatographic separation of a mixture of 30 common organic vapors using our three-stage /spl mu/PCF in a conventional GC system. The peak width at half height is <2.05 s for all compounds after elution from the GC column.