CURRICULUM VITA

 

 

Wei-Heng Shih

Department of Materials Engineering

Philadelphia, PA 19104

shihwh@drexel.edu, http://ceramicslab.materials.drexel.edu/

 

PERSONAL INFORMATION

 

            Date of Birth: February 3, 1954

            Citizenship: USA

            President of Chinese Cultural Association of Greater Philadelphia, 1999-2001, 2002-2004

            Principal of Main Line Chinese School, 2001-2002

 

EDUCATION

 

Ph.D.               1984                Ohio State University, Columbus, Ohio

                                                Department of Physics

B.Sc.               1976                Tsing-Hua University, Hsinchu, Taiwan, ROC

                                                Department of Physics

 

POSITIONS HELD

 

Professor                                             Dept. of Materials Science & Engineering     9/1/03-present

Drexel University

Visiting Professor (Sabbatical leave)  National Taiwan University, Taiwan                12/15/06-5/15/07

Associate Professor                             Dept. of Materials Engineering                       9/1/96-8/31/03

Drexel University

Visiting Researcher                             Catalytic Systems Division                             7/1/98-3/31/99

(Sabbatical leave)                                Johnson Matthey, Wayne, PA

Visiting Associate Professor               Dept. of Applied Chem. and Chem. Eng.      6/97-8/97

Kagoshima University, Japan

Visiting Associate Professor               National Taiwan University, Taiwan              8/97

Assistant Professor                             Dept. of Materials Engineering                       4/1/91-8/31/96

Drexel University

Visiting Summer Faculty                    Naval Air Warfare Center, Warminster, PA   7/93-9/93

Research Scientist                               Dept. of Materials Science & Engineering     9/87-3/91

University of Washington, Seattle, WA

Visiting Researcher                             Academia Sinica, Taipei, Taiwan                    12/88-2/89

Postdoctoral Research Associate        Dept. of Physics, University of Washington 1985-1987

Postdoctoral Research Associate        Dept. of Physics, Ohio State University         1984-1985

 

AWARDS

 

1.      Voted the Best Professor of Materials Engineering Department by the graduating class of 1996

2.      The American Ceramic society 1999 Edward C. Henry Electronics Division Best Paper Award for “Electromechanical Behavior of PZT-Brass Unimorphs,” J. Am Ceram. Soc. 82[7], 1733-1740 (1999) by X. Li, W.Y. Shih, I. A. Aksay, and W.-H. Shih

3.      Faculty Achievement Award for excellence in teaching at Drexel, Feb. 23, 2000

4.      Professor of the Year, College of Engineering, Student Choice Awards, 2001

5.      Winner of Best Senior Design Project in Department of Materials Engineering, Drexel University, M. P. Rossi, 2002

6.      Winner of Best Senior Design Project in Department of Materials Engineering, Drexel University, Steve Szewczyk, 2003

7.      Best Poster in Drexel Research Day, Undergraduate category, Robert Luchenta and W.-H. Shih, 2003

8.      Inducted to Drexel 106 Club

9.      Research Achievement Award, Drexel University 2004

10.  Best Poster in 2004 Drexel Research Day, Graduate category in Emerging Technology, Hongyu Luo, C. Martorano, W. Y. Shih, and W.-H. Shih

11.  Teaching Award, Department of Materials Science and Engineering, Drexel University 2004

12.  2nd place best poster at the 4th annual poster contest for graduate students of the Philadelphia "Liberty Bell" Chapter of ASM International, 2005, Hui Li, W. Y. Shih, and W.-H. Shih

13.  Best poster award at the 2005 Research Day, College of Engineering, Drexel University, Hakki O. Yegingil, Wan Y Shih, Waqas Anjum, Jeffrey Justin, Ari D Brooks, and Wei-Heng Shih

14.  Travel Grant for Hakki O. Yegingil to attend 2005 MRS Fall Meeting

15.  Koerner Fellowship awarded to Joe Capobianco, 2007

 

RESEARCH AREAS

           

1. Colloidal Coating: A Novel Ceramic Processing Approach

            Aqueous colloidal processing has the advantages of controlling the interactions between particles and environmental friendliness. I have developed a colloidal coating method that modifies the surface of ceramic powders by nanolayering. The nanolayer coating serves multiple functions. It can enhance the chemical and thermal stability of the powders, improve the consolidation and rheological properties of slurries, and lower the sintering temperatures of the green compacts. For example, silicon nitride and silicon carbide powders were coated by boehmite (AlOOH) via a sol-gel process. The coated powder suspensions were shown to have a significantly higher solids loading than the uncoated powder in water. Viscosity measurements and centrifugation showed that the coating changes the long-range interaction between the silicon nitride particles. Rheological studies indicate that the suspensions of coated powders have lower viscosity and wider linear viscoelastic region than that of uncoated powders. Furthermore, as the coating thickness increases, the shear modulus of boehmite-coated SiC gel decreases because the boehmite coating prevents the close contact of the SiC particles thereby reducing the van der Waals attraction interaction between the SiC particles. We have extended this part of research to the biomedical applications of nanometric hydroxyapatite coating for implant surface modifications. Additionally, we have also synthesized microporous and mesoporous nanostructured materials that are suitable for enzyme immobilization and absorbents for environmental wastes.

 

2. Low-Temperature Processing of Piezoelectric Ceramics with Enhanced Properties

Based on the nanocoating approach, a low-temperature, direct sintering approach for high performance perovskite lead magnesium niobate-lead titanate (PMN-PT) solid solution ceramics was developed using Mg(OH)2-coated Nb2O5 particles. The mixtures of Mg(OH)2-coated Nb2O5, PbO particles, and lead titanate particles are compacted and sintered to near full density at temperatures lower than 1000ºC with superior dielectric and piezoelectric properties.

More recently, we developed a method to fabricate freestanding piezoelectric films with giant electric-field-enhanced piezoelectric response. The d31 piezoelectric coefficient for PMN-PT layers can be as high as 2000 pm/V, larger than that of commercial single crystalline PMN-PT bulk, at 10 kV/cm (or 20 V over the 20-micron film thickness). In contrast to single crystals, the polycrystalline freestanding films are easy to make and can be made into any size. They are also easy to be miniaturized. The method can be applied to any piezoelectric material. The freestanding films can be easily stacked to form multilayer actuators as well as multilayer capacitors. They are ideal for miniaturized sensors and actuators applications. (US patent pending)

 

3. Aqueous Synthesis of Nanocrystalline Semiconductors: Quantum Dots

            We have developed a direct synthetic method for producing water soluble quantum dots (QDs) that are ready for bioconjugation. The method can produce aqueous QDs with wavelength varying from 400 nm to 700 nm. Highly luminescent metal sulfide (MS) QDs are produced in an aqueous synthesis route.  MS QDs are capped with thiol-containing charged molecules in a single step. The resultant MS QDs exhibit the distinctive excitonic photoluminescence desired of QDs and can be fabricated to avoid undesirable broadband emissions at higher wavelengths. This provides a significant improvement over the present complex and expensive commercial processes for the production of QDs. The aqueous QDs are stable in biological fluids over a long period of time. In addition, nontoxic ZnS QDs have been produced with good photoluminescence properties by refluxing the ZnS QD suspensions over a period of time. (US patent pending)

 

4. Synthesis of Dispersed Hydroxyapatite Particles and Gels

Hydroxyapatite, Ca10(PO4)6(OH)2, was synthesized using a sol-gel method. When sufficient amount of citric acid or sodium citrate was added to the precursor salts, a translucent suspension was formed, in contrast to the opaque suspension obtained without the citrate addition. Particle size analysis found that the size of the HA varied from 2.5 mm to 4 mm when the citrate concentration is below 0.8 M. Above 0.8 M of citrate, the particle size was 0.1 mm. In addition, the Ca/P ratio in the particles made with sodium citrate is higher than that without sodium citrate. The gelation behavior of the submicron HA particles was used for the fabrication of coatings on implant surface for bioactivity study.

 

5. Piezoelectric Cantilever Sensor (PECS)

The piezoelectric cantilever sensor consists of a piezoelectric, e.g., PZT layer bonded to a nonpiezoelectric metal strip. Coating the cantilever surface with the antibody specific to a target antigen, we were able to detect the small mass change in the cantilever due to the binding of the target antigen to the antibody coated on the cantilever surface by monitoring the cantilever resonance frequency shift. This approach has been extended to directly detect and quantify biological substances such as cells and proteins in real time. With suitable receptor on the metal tip, detection of biological substances such as yeast cells, protein molecules (avidin, and avidin-biotin binding), bacteria E. coli and salmonella have been demonstrated. PECS is also excellent sensor for in-air detection. Array PECS can be used to selectively detect gaseous species including biological and chemical warfare agents. The cantilever sensor has been used to detect gas species such as dimethyl methylphosphonate (DMMP), a nerve gas simulant. Utilizing the coating method that I developed, we have made freestanding PMN-PT tapes that were electroplated to form piezoelectric microcantilevers having a sensitivity of 10-12 g/Hz. Comparing to the current quartz microbalance (QCM) technology, the piezoelectric cantilever sensor has the advantages of miniaturization, forming arrays, and compatible with microelectronics. The piezoelectric cantilever sensor has the advantage that it can be miniaturized easily and incorporated in a small device. A PECS has the driver, the vibrator, and the detector all in one device using simple electrical means. The sensor is compact and easily portable. A  PECS of 50 microns in length can reach unprecedented femtogram sensitivities, smaller than the mass of a single virus or a fraction of a bacterium.

In addition, a PEC can also measure a liquid’s viscosity and density over a wide range of viscosity, e.g., from less than 1 cp to larger than 4000 cp. A hand-held measuring unit has been built to complete the portable PEC sensor system. (US patent pending)

6. Piezoelectric Finger (PEF) for Soft-tissue Stiffness Detection/Imaging

Cancerous tissues and tumors are stiffer than surrounding tissues. Measurement of tissue stiffness could aid early tumor/cancer location. Ability to measure tumor stiffness under shear in the DC mode, which none of the current technology could achieve, could greatly improve the accuracy of tumor malignancy diagnosis. The PEF that we developed is an “electronic finger” capable of accurately and non-destructively measuring both the Young’s modulus and shear modulus of tissues with gentle touches to the surface. A PEF can measure the Young’s modulus and shear modulus variations in tissues with less than one-millimeter spatial resolution to a depth of up to several centimeters, offering great potential for in-vivo early detection of diseases such as breast cancer tumor. The ability of a PEF to probe the interfacial properties of hard inclusions by comparing the DC compression and shear tests stands to greatly aid tumor malignancy test accuracy. Preliminary results indicated that a PEF is capable of identifying and locating small malignant tumors (less than 3 mm) that were missed by mammography, ultrasound and a physician’s palpation. (US patent pending) 

 

7. High Surface-Area Catalytic Oxides

 

            High surface-area powders are a critical component in many catalytic systems. The thermal stability of these ceramic powders is essential to the performance of catalytic systems. We have been studying the synthesis of oxide nanoparticles such as ZrO2, CeO2, Al2O3, SiO2, and MnOx with the aim of maintaining high surface area at elevated temperatures. It was shown that impurities within the powders are a key factor in determining the thermal stability of oxide powders. Furthermore, synthesis conditions such as heat treatment temperature and time, as well as precursor concentration were shown to be controlling parameters in achieving high surface area. We discovered that the colloidal coating approach of precipitation an oxide in the presence of the support oxide can enhance the surface area of the mixed oxides due to morphological change. Our study provides a basic understanding to the important industrial processes in obtaining thermally stable, high surface-area ceramic particles.

 

8. Size Effect in Nanoparticles

            The crystalline structure of BaTiO3 nanoparticles has been shown by many authors to depend on the size of the particles. However, the reason for the size dependence is not clear. We showed that the size effect of crystalline structure of BaTiO3 is related to the depolarization effect of the small particles. The large depolarization energy prohibits the small particles from becoming polarized (the tetragonal structure) and causes the particles to remain as unpolarized (the cubic structure). The depolarization effect is demonstrated by coating the BaTiO3 particles with Cu and that the tetragonality of the powders (c/a lattice constant ratio) is enhanced by the metal coating. After oxidation of the metal coating, the tetragonality of BaTiO3 powders decreases. In addition, it is shown that particle clustering can stabilize the tetragonal structure down to a smaller particle size than individual BaTiO3 particles due to the reduction of depolarization energy by clustering.

            Size also plays an important role in the coating of particles. We found that nanoparticles were difficult to coat compare to micron-sized particles due to higher solubility of the small particle size. Size effect also plays an important role of the emission spectrum of quantum dots that we synthesized.

 

9. Conversion of Coal Wastes into Microporous and Mesoporous Materials

            Annually, in the state of Pennsylvania alone, 8.4 million tons of fly ash, a coal combustion waste, is generated. Due to the increasingly tighter environmental regulations, the disposal of such a large amount of fly ash poses a challenge. In the past few years, we have chemically converted fly ash into zeolites which have a wide range of applications such as molecular sieves, catalysts, adsorbents, etc. Zeolites are crystalline forms of aluminosilicates and the fly ash is composed of mainly silica and alumina. Therefore, it is expected that fly ash can be converted to zeolites. This study represents a new approach in dealing with waste materials. It not only eliminates the disposal problem of coal wastes and more importantly turns the waste material into a useful one. We have found a fusion method that can convert a variety of ashes into zeolites with high yields. The zeolites converted from fly ash were shown to have good ion-exchange property with heavy metals such as Cs and Co. Our results show that the converted fly ash has a great potential in immobilizing nuclear wastes and toxic ions in waste streams.

            As an extension of our work on zeolites, the formation of mesoporous molecular sieves that were recently discovered by researchers at Mobil was investigated. The mesoporous molecular sieves are composites of organic (surfactant) and inorganic (for example, silicate) species. After calcination (heat treatment), the organic part is burned out and the remaining porous materials contain periodic pores of sizes in the order of 20-100 angstroms. The mesoporous materials have a wide range of possible applications such as catalysts, molecular sieves, and adsorbents. We have succeeded in converting fly ashes into mesoporous aluminosilicates. Furthermore, we synthesized mesoporous nickel silicates using the same approach. The mesoporous nickel silicates show great promise as energy storage electrodes in electrochemical cells. Currently our expertise in this area has been applied to the separation of CO2/N2 gases. In the DOE funded program, we worked on synthesizing a microporous membrane material that can effectively separate CO2 from N2 due to preferential adsorption of CO2.

 

PUBLICATIONS

 

Patents

 

  1. J. Vartuli, D. L. Milius, Xiaoping Li, W.-H. Shih, W. Y. Shih, R. K. Prud'homme, and I. A. Aksay, "Multilayer Ceramic Piezoelectric Laminates with Zinc Oxide Conductors," United States Patent #6,329,741 issued Dec. 11, 2001.
 
US Patent Applications

 

  1. Wan Y. Shih, Wei-Heng Shih, and Zuyan Shen, “Piezoelectric Cantilever Sensor,” Patent Application No. PCT/US2004/036705, October 27, 2004.
  2. Wei-Heng Shih, Wan Y. Shih, and Huiming Gu, “Method of Making Mixed Metal Oxide Ceramics,” US Patent Application No. 10/981,985, Nov. 6, 2004.
  3. Wei-Heng Shih, Hui Li, Melissa Schillo, and Wan Y. Shih, “Synthesis of Water Soluble Nanocrystalline Quantum Dots and Uses Thereof,” US Patent application No. 60/573,804, May 24, 2005.
  4. Wan Y. Shih, Wei-Heng Shih, Anna Markidou, Stephen T. Szewczyk, and Hakki Yegingil, “All-electrical Piezoelectric Finger Sensor (PEFS) for Soft Material Stiffness Measurement,” Patent Application No. PCT/US2004/036705, May, 2005.
  5. Wei-Heng Shih, Hongyu Luo, Christian Martorano, and Wan Y. Shih, “Freestanding Films with Giant Electric-Field-Enhanced Piezoelectric Coefficients,” US patent application No. 11/392,116, filed March 29, 2006

 

Provisional Patent applications

 

  1. Wan Y. Shih, Wei-Heng Shih, and Joseph A. Capobianco, “Electrical Insulation of Micro- and Nano-Devices by Bi-Functional Thin Layers for In-Water Applications,” filed in July 7, 2006. US Provision patent application No. 60/806,765.
  2. Wei-Heng Shih, Wan Y. Shih, Zuyan Shen, Huidong Li, and Xiaotong Gao, “Sol-Gel Synthesis of Lead-Based Perovskite Thin Films Through Multiple Depositions,” filed in November 6, 2006. US Provision patent application No. 60/864,470.
  3. Wei-Heng Shih, Wan Y. Shih, and Hakki Yegingil, “Piezoelectric Energy Harvesting Device,” filed in January 29, 2007. US Provision patent application No. 60/887,051.
  4. Wan Y. Shih, Wei-Heng Shih, and Zuyan Shen, “Piezoelectric Microcantilevers and Uses in Atomic Force Microscopy,” filed on November 6, 2006, US provisional patent application No. 60/867,539.
  5. Wan Y. Shih, Wei-Heng Shih, Zuyan Shen, Qing Zhu, Joseph Capobianco, and John-Paul McGovern, “Piezoelectric Microcantilever Sensors for Biosensing,” filed on November 6, 2006, US provisional patent application No. 60/867,538
  6. Wei-Heng Shih, Wan Y. Shih, and Hui Li, “Synthesis of Water Soluble Nanocrystalline ZnS Quantum Dots and Uses Thereof,” filed on November 28, 2006, US provisional patent application No. 60/867,245
  7. Wan Y. Shih and Wei-Heng Shih, “A Hand-Held Phase-Shift Detector for Sensor Applications,” filed on February 1, 2007, US provisional patent application No. 60/887,686
  8. W.-H. Shih, W. Y. Shih, “Specificity and sensitivity enhancement in cantilever sensing,” filed on Oct. 4, 2007, US provisional Patent application No. 60/977776

 

Archival Journal Papers

 

1.      W.-H. Shih and D. Stroud, “Theoretical Study of Freezing of Polystyrene Sphere Suspensions,” J. Chem. Phys., 79, 6254 (1983)

2.      W.-H. Shih and D. Stroud, “Theoretical Study of Miscibility and Glass-Forming Trends in Mixtures of Polystyrene Spheres,” J. Chem. Phys., 80, 4429 (1984)

3.      W.-H. Shih and D. Stroud, “Thermodynamic Properties of Liquid Si and Ge,” Phys. Rev. B, 31, 3715 (1985)

4.      W.-H. Shih and D. Stroud, “Theory of Surface Tension of Liquid Metal Alloys,” Phys. Rev. B, 32, 804 (1985)

5.      W.-H. Shih and D. Stroud, “Two-Component Lattice-Gas Model for Surface Segregation in Liquid Alloys,” Phys. Rev. B, 33, 8048 (1986)

6.      M. Schick and W.-H. Shih, “Spin 1 Model of a Microemulsion,” Phys. Rev. B, 34, 1797 (1986)

7.      W.-H. Shih, C. Ebner, and D. Stroud, “Potts Lattice-Gas Model for the Solid-Liquid Interfacial Tensions of Simple Fluids,” Phys. Rev. B, 34, 1811 (1986)

8.      Y. Gefen, W.-H. Shih, R. B. Laibowitz, and J. M. Viggiano, “Nonlinear Behavior Near the Percolation Metal-Insulator Transition,” Phys. Rev. Lett., 57, 3097 (1986)

9.      M. Schick and W.-H. Shih, “Z(N) Model of Grain-Boundary Wetting,” Phys. Rev. B, 35, 5030 (1987)

10.  J. Adler, Y. Gefen, M. Schick, and W.-H. Shih, “Order Propagation on Dilute Antiferromagnetic Potts Models,” J. Phys. A:  Math. Gen., 20, L227 (1987)

11.  W.-H. Shih, Z. Q. Wang, X. C. Zeng, and D. Stroud, “Ginzburg-Landau Theory for the Solid-Liquid Interface of BCC Elements,” Phys. Rev. A, 35, 2611 (1987)

12.  M. Schick and W.-H. Shih, “Simple Microscopic Model of a Microemulsion,” Phys. Rev. Lett., 59, 1205 (1987)

13.  H. F. Cheung, Y. Gefen, E. Riedel, and W.-H. Shih, “Persistent Currents in Small One-Dimensional Metal Rings,” Phys. Rev. B, 37, 6050 (1988)

14.  W. Y. Shih, W.-H. Shih, and I. A. Aksay, “Stability of Binary Charged Colloidal Crystals,” J. Chem. Phys., 90, 4506 (1989)

15.  W.-H. Shih, W. Y. Shih, S. I. Kim, J. Liu, and I. A. Aksay, “Scaling Behavior of Elastic Properties of Colloidal Gels,” Phys. Rev. A, 42, 4772 (1990)

16.  W. Y. Shih, W.-H. Shih, and I. A. Aksay, “Semi-Dilute Athermal Polymer Solutions Near a Hard Wall: Monte Carlo Simulations,” Macromolecules, 23, 3291 (1990)

17.  W. Y. Shih, J. Liu, W.-H. Shih, and I. A. Aksay, “Aggregation of Colloidal Particles with a Finite Interparticle Attraction Energy,” J. Stat Phys., 62, 961 (1991)

18.  A. A. Tseng, W.-H. Shih, C. Thomas, S. Chen, “Intelligent Processing of Polymer Sheets for Calendering,” Adv. in Poly. Tech., 12, 241 (1993)

19.  W.-H. Shih, W. Y. Shih, and I. A. Aksay, “Equilibrium-State Density Profiles of Centrifuged Cakes,” J. Am. Ceram. Soc., 77, 540 (1994)

20.  W.-H. Shih and Q. Lu, “Ultrafine Titanate Powders Processed via a Precursor-Modified Sol-Gel Method, ”Ferroelectrics, 154, 241-46 (1994)

21.  W. Y. Shih, W.-H. Shih, and I. A. Aksay, “Size Effect in the Ferroelectric Properties of Small BaTiO3 Particles: Effect of Depolarization,” Phys. Rev. B, 50, 15575 (1994)

22.  W. Y. Shih, W.-H. Shih, and I. A. Aksay, "Elimination of an Isolated Pore: Effect of Grain Size," J. Mat. Res., 10[4], 1000-1015 (1995)

23.  W.-H. Shih, D. Kisailus, and Y. Wei, "Silica Coating of Barium Titanate Particles," Materials Lett., 24, 13-15 (1995)

24.  W.-H. Shih, L.-L. Pwu, A. A. Tseng, “Boehmite Coating as Consolidation and Sintering Aids in Aqueous Silicon Nitride Processing,” J. Am. Ceram. Soc., 78[5], 1252-1260 (1995)

25.  W.-H. Shih and L.-L. Pwu, “Rheology of Aqueous Boehmite-Coated Silicon Nitride Suspensions and Gels,” J. Mat. Res., 10[11], 2808-16, (1995)

26.  W.-H. Shih, D. Kisailus, W. Y. Shih, Y.-H. Hu, J. Hughes, "Rheology and Consolidation of Colloidal Alumina-Coated Silicon Nitride Suspensions," J. Am. Ceram. Soc., 79[5], 1155 (1996)

27.  W. Y. Shih, W.-H. Shih, and I. A. Aksay, "Heteroflocculation in Binary Colloidal Suspensions: Monte Carlo Simulations," J. Am. Ceram. Soc., 79[10], 2587-91 (1996)

28.  M. Buchta and W.-H. Shih, "Improved Aqueous Dispersion of Silicon Nitride with Aminosilanes," J. Am. Ceram. Soc., 79[11], 2940-46 (1996)

29.  W.-H. Shih and H.-L. Chang, "Conversion of Fly Ash into Zeolites for Ion-Exchange Applications," Mat. Lett., 28, 263-68 (1996)

30.  W. Y. Shih, W.-H. Shih, and I. A. Aksay, "Scaling Analysis for the Axial Displacement and Pressure of Flextensional Transducers," J. Am. Ceram. Soc., 80[5], 1073-78 (1997)

31.  X. Liu, W. Y. Shih, and W.-H. Shih, "Effect of Copper Coating on the Crystalline Structure of Small BaTiO3 Particles," J. Am. Ceram. Soc., 80[11], 2781-88 (1997)

32.  X. Li and W.-H. Shih, "Size Effects in BaTiO3 Particles and Clusters," J. Am. Ceram. Soc., 80[11], 2844-52 (1997)

33.  H.-L. Chang and W.-H. Shih, "A General Method for the Conversion of Fly Ash into Zeolites as Ion Exchangers for Cesium," Ind. Eng. Chem. Res., 37, 71-78 (1998)

34.  Y. Wei, D. Jin, T. Ding, W.-H. Shih, X. Liu, S. Z. D. Cheng, and Q. Fu, "A Non-Surfactant Templating Route to Mesoporous Silica Materials," Adv. Mater., 3[4], 313-316 (1998)

35.  P. C. Y. Lee, J.-D. Yu, X. Li, and W.-H. Shih, “Piezoelectric Ceramic Disks with Thickness-Graded Material Properties,” IEEE Trans. Ultrasonics, Ferro. Freq. Control, 46[1] 205-215 (1999)

36.  C.-Y. Yang and W.-H. Shih, “Effect of pH on the Boehmite Coating on SiC,” J. Am. Ceram. Soc. 82[2] 436-440 (1999)

37.  W. Y. Shih, W.-H. Shih, and I. A. Aksay, “Elastic and Yield Behavior of Strongly Flocculated Colloids,” J. Am. Ceram. Soc. 82[3] 616-624 (1999)

38.