Browsing by Author "Wu, Jong-Shinn"

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A Cold Planar Nitrogen-Based Atmospheric-Pressure Dielectric Barrier Discharge Jet With Enhanced UV Emission and Radical Generation Using Short Electrodes
(2016-12)
Cheng, Kuang-Yao
;
Yang, Yi-Wei
;
Lin, Zhi-Hua
;
Liao, Guo-Chun
;
Liu, Chih-Tung
In this paper, a planar nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet with enhanced UV emission and radical generation, and much lower power consumption and gas temperature using shorter electrodes as compared with a previously developed DBD jet is presented. The highest UV intensity (five times larger) and radical generation (two times larger) in the DBD jet region are found to occur when the electrode length is 1 cm. Corresponding jet gas temperature and power consumption are 31 degrees C and 39 W, respectively. The 1-cm DBD jet was used to treat polylactide film for enhancing its hydrophilic properties. The results show that a contact angle of 28.4 degrees could be obtained with a residence time of 4 s. The resulting 1-cm DBD jet may provide an efficient surface treatment tool for delicate industrial and biomedical devices/materials.
A Cold Planar Nitrogen-Based Atmospheric-Pressure Dielectric Barrier Discharge Jet With Enhanced UV Emission and Radical Generation Using Short Electrodes
(2016-12-01)
Cheng, Kuang-Yao
;
Yang, Yi-Wei
;
Lin, Zhi-Hua
;
Liao, Guo-Chun
;
Liu, Chih-Tung
In this paper, a planar nitrogen-based atmospheric-pressure dielectric barrier discharge (DBD) jet with enhanced UV emission and radical generation, and much lower power consumption and gas temperature using shorter electrodes as compared with a previously developed DBD jet is presented. The highest UV intensity (five times larger) and radical generation (two times larger) in the DBD jet region are found to occur when the electrode length is 1 cm. Corresponding jet gas temperature and power consumption are 31 degrees C and 39 W, respectively. The 1-cm DBD jet was used to treat polylactide film for enhancing its hydrophilic properties. The results show that a contact angle of 28.4 degrees could be obtained with a residence time of 4 s. The resulting 1-cm DBD jet may provide an efficient surface treatment tool for delicate industrial and biomedical devices/materials.
A Novel Fabrication of PDMS Chip using Atmospheric Pressure Plasma Jet: Hydrophobicity Modification and Feasibility Test
(2018-01-01)
Yu, Ya-Shen
;
Kuo, Lih-Hwa
;
Wu, Mu-Chien
;
Wu, Jong-Shinn
;
Tsai, Chia-Hung Dylan
This paper presents a new application of atmospheric pressure plasma jet (APPJ) aiming for fabricating a microfluidic system on a polydimethylsiloxane (PDMS) surface. While PDMS is widely used for microfluidic chips, the fabrication of a chip requires different instruments which are not easily accessible for small-scale companies or laboratories. Therefore, we are motivated to develop a simple and low-cost method for such a fluidic system fabrication. The idea of this work is to directly pattern a fluidic channel on a PDMS surface with a plasma jet, which is known for its capability of modifying the hydrophobicity on a surface. The feasibility test first showed that fluid only flows in plasma-treated regions as having physical walls. The plasma parameters were then optimized using Taguchi method based on experiments. The optimization significantly reduce the required plasma treating time from more than 30 treating rounds to only 3 treating rounds, over ten times improved. Methods for further improving the resolution to micrometer-scale have been discussed. In addition to the advantages of fast and low-cost of the proposed method, making microfluidic channels on the surfaces of PDMS chip is also convenient for recollecting cultured cells on a chip in the field of regenerative medicine.
Ab Initio Chemical Kinetics for Reactions of H Atoms with SiHx (x=1-3) Radicals and Related Unimolecular Decomposition Processes
(2013-06-15)
Raghunath, Putikam
;
Lee, Yun-Min
;
Wu, Shang-Ying
;
Wu, Jong-Shinn
;
Lin, Ming-Chang
Hydrogen atoms and SiHx (x = 1-3) radicals coexist during the chemical vapor deposition (CVD) of hydrogenated amorphous silicon (a-Si: H) thin films for Si-solar cell fabrication, a technology necessitated recently by the need for energy and material conservation. The kinetics and mechanisms for H-atom reactions with SiHx radicals and the thermal decomposition of their intermediates have been investigated by using a high high-level ab initio molecular-orbital CCSD (Coupled Cluster with Single and Double)(T)/CBS (complete basis set extrapolation) method. These reactions occurring primarily by association producing excited intermediates, (SiH2)-Si-1, (SiH2)-Si-3, SiH3, and SiH4, with no intrinsic barriers were computed to have 75.6, 55.0, 68.5, and 90.2 kcal/mol association energies for x = 1-3, respectively, based on the computed heats of formation of these radicals. The excited intermediates can further fragment by H-2 elimination with 62.5, 44.3, 47.5, and 56.7 kcal/mol barriers giving Si-1, Si-3, SiH, and (SiH2)-Si-1 from the above respective intermediates. The predicted heats of reaction and enthalpies of formation of the radicals at 0 K, including the latter evaluated by the isodesmic reactions, SiHx + CH4 SiH4 + CHx, are in good agreement with available experimental data within reported errors. Furthermore, the rate constants for the forward and unimolecular reactions have been predicted with tunneling corrections using transition state theory (for direct abstraction) and variational Rice-Ramsperger-Kassel-Marcus theory (for association/decomposition) by solving the master equation covering the P, T-conditions commonly employed used in industrial CVD processes. The predicted results compare well experimental and/or computational data available in the literature. (C) 2013 Wiley Periodicals, Inc.
Ab Initio Chemical Kinetics for the Unimolecular Decomposition of Si2H5 Radical and Related Reverse Bimolecular Reactions
(2014-02-15)
Wu, Shang-Ying
;
Lee, Yun-Min
;
Wu, Jong-Shinn
;
Lin, Ming-Chang
;
機械工程學系
For plasma enhanced and catalytic chemical vapor deposition (PECVD and Cat-CVD) processes using small silanes as precursors, disilanyl radical (Si2H5) is a potential reactive intermediate involved in various chemical reactions. For modeling and optimization of homogeneous a-Si:H film growth on large-area substrates, we have investigated the kinetics and mechanisms for the thermal decomposition of Si2H5 producing smaller silicon hydrides including SiH, SiH2, SiH3, and Si2H4, and the related reverse reactions involving these species by using ab initio molecular-orbital calculations. The results show that the lowest energy path is the production of SiH+SiH4 that proceeds via a transition state with a barrier of 33.4 kcal/mol relative to Si2H5. Additionally, the dissociation energies for breaking the SiSi and HSiH2 bonds were predicted to be 53.4 and 61.4 kcal/mol, respectively. To validate the predicted enthalpies of reaction, we have evaluated the enthalpies of formation for SiH, SiH2, HSiSiH2, and Si2H4(C-2h) at 0 K by using the isodesmic reactions, such as (HSiSiH2)-H-2+(C2H6Si2H6)-C-1-Si-1+(HCCH2)-H-2 and (Si2H4)-Si-1(C-2h)+(C2H6)-C-1 (Si2H6)-Si-1+(C2H4)-C-1. The results of SiH (87.2 kcal/mol), SiH2 (64.9 kcal/mol), HSiSiH2 (98.0 kcal/mol), and Si2H4 (68.9 kcal/mol) agree reasonably well previous published data. Furthermore, the rate constants for the decomposition of Si2H5 and the related bimolecular reverse reactions have been predicted and tabulated for different T, P-conditions with variational Rice-Ramsperger-Kassel-Marcus (RRKM) theory by solving the master equation. The result indicates that the formation of SiH+SiH4 product pair is most favored in the decomposition as well as in the bimolecular reactions of SiH2+SiH3, HSiSiH2+H-2, and Si2H4(C-2h)+H under T, P-conditions typically used in PECVD and Cat-CVD. (c) 2013 Wiley Periodicals, Inc.
Aerosol-Assisted Plasma Deposition of Biocomposite Coatings: Investigation of Processing Conditions on Coating Properties
(2016-12)
Hsiao, Chun-Ping
;
Wu, Cheng-Chen
;
Liu, Yung-Hsin
;
Yang, Yi-Wei
;
Cheng, Yun-Chien
The aerosol-assisted atmospheric-pressure planar dielectric-barrier-discharge-type plasma deposition (AA-APPD) system can polymerize monomers and immobilize biomolecules simultaneously. In this paper, we used this technology to deposit biocomposite thin films of polyethylene (PE) along with lysozyme (Lyz) under different aerosol solution temperatures and at different coating positions in the discharge region. In addition, we compared the deposition efficacy of two kinds of Lyz solution using deionized (DI)-water and phosphate-buffered saline (PBS) as solvents, respectively. The results show that deposition rate of thin films increases with increasing solution temperature at most coating positions. In addition, coatings from Lyz-PBS perform higher deposition rates, but with weaker Lyz viability as compared with that of Lyz DI-water. Finally, we also verified that this DBD-type AA-APPD system can not only successfully deposit Lyz in PE thin film, but also maintain Lyz viability after plasma process under different solution temperatures and positions.
Aerosol-Assisted Plasma Deposition of Biocomposite Coatings: Investigation of Processing Conditions on Coating Properties
(2016-12-01)
Hsiao, Chun-Ping
;
Wu, Cheng-Chen
;
Liu, Yung-Hsin
;
Yang, Yi-Wei
;
Cheng, Yun-Chien
The aerosol-assisted atmospheric-pressure planar dielectric-barrier-discharge-type plasma deposition (AA-APPD) system can polymerize monomers and immobilize biomolecules simultaneously. In this paper, we used this technology to deposit biocomposite thin films of polyethylene (PE) along with lysozyme (Lyz) under different aerosol solution temperatures and at different coating positions in the discharge region. In addition, we compared the deposition efficacy of two kinds of Lyz solution using deionized (DI)-water and phosphate-buffered saline (PBS) as solvents, respectively. The results show that deposition rate of thin films increases with increasing solution temperature at most coating positions. In addition, coatings from Lyz-PBS perform higher deposition rates, but with weaker Lyz viability as compared with that of Lyz DI-water. Finally, we also verified that this DBD-type AA-APPD system can not only successfully deposit Lyz in PE thin film, but also maintain Lyz viability after plasma process under different solution temperatures and positions.
An Approximate Method for Solving Unsteady Transitional and Rarefied Flow Regimes in Pulsed Pressure Chemical Vapor Deposition Process using the Quiet Direct Simulation Method
(2011)
Lim, Chin Wai
;
Cave, Hadley M.
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Jermy, Mark C.
;
Krumdieck, Susan P.
;
Wu, Jong-Shinn
The Quiet Direct Simulation (QDS) method is a kinetic-based flux scheme that computes true-direction fluxes of mass, momentum and energy with high computational efficiency. In QDS, the molecular velocity is represented by the Maxwell-Boltzmann equilibrium distribution approximated by a Gauss-Hermite quadrature. The QDS algorithm is suitable for parallelization with its highly local nature. In this paper, the QDS method is used to simulate highly unsteady low pressure flows encountered in a Pulsed Pressure Chemical Vapor Deposition (PP-CVD) reactor. Two simulations were conducted to study the PP-CVD reactor flow field at 1Pa and 1 kPa reactor base pressures. The time required to establish the quasi-steady under-expanded jet is found to be similar to 5ms, and the jet dissipates within 1ms of the end of injection. Simulation results also show uniform molecular arrival at the depositing substrate surface to promote uniform deposition. This important information is important to set up PP-CVD operating conditions as well as the reactor design. The assumption of the local Maxwell-Boltzmann equilibrium distribution used in the QDS scheme is then verified by examining the gradient length local Knudsen number based on the density, and by estimating the average number of particles collisions within each computational cell in one computational time step. The validity of local equilibrium assumption is found satisfactory at I kPa reactor based pressure but not at 1Pa. However, the similarity of flow phenomena in both simulations suggests QDS to be a quick approximation method for low pressure flow simulations.
An Optimized Two-Step Nitrogen-Based Plasma Treatment Procedure under Atmospheric-Pressure Condition and its Surface Amination Mechanism
(2015-07-01)
Yang, Yi-Wei
;
Wu, Jane-Yii
;
Liu, Chih-Tung
;
Liao, Guo-Chun
;
Cheng, Kuang-Yao
Atmospheric pressure nitrogen-based dielectric barrier discharge (DBD) jet with two-step plasma treatment procedure has been verified to be very effective in facilitating nitrogen-containing group incorporation on Polylactide (PLA) surface. It includes: 1) pretreatment plasma treatment by a nitrogen discharge with a trace amount of oxygen, and 2) ammonia plasma treatment by a nitrogen discharge with a small amount of ammonia. In this study, the optimized operation condition of two-step plasma procedure is investigated under different concentrations of added gases (0-1% oxygen; 0-10% ammonia). XPS analysis shows that approximate to 0.19 of N/C ratio can be achieved by means of the optimized two-step plasma procedures. Furthermore, a surface amination mechanism is proposed based on the observations of Optical Emission Spectra (OES), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectra (XPS) analyses.
Analysis of Hydroxyl Radical and Hydrogen Peroxide Generated in Helium-Based Atmospheric-Pressure Plasma Jet and in Different Solutions Treated by Plasma for Bioapplications
(2020-06-22)
Chen, Tsung-Wen
;
Liu, Chih-Tung
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Chen, Chao-Yu
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Wu, Mu-Chien
;
Chien, Po-Chien
This study systematically analyzed reactive species generated with self-built helium-based low-temperature atmospheric-pressure plasma jet (He-APPJ); we measured the hydroxyl radical (OH) and hydrogen peroxide (H2O2) above surfaces of plasma-treating solutions and in plasma-treated medium (PTM) of different solutions, including deionized water, phosphate buffered saline, and Dulbecco's modified Eagle medium. The effects of adding O(2)into He working gas on OH and H(2)O(2)generation were discussed. The MCF7 cell responses to plasma treatment were also observed. The OH emission (309 nm) in He-APPJ and above surfaces of plasma-treating solutions were analyzed through optical emission spectroscopy, and concentrations of OH and H(2)O(2)in different solutions were measured using terephthalic acid and Amplex Red, respectively. In our plasma system, it was observed that higher conductivity of solutions may cause stronger OH emission above solution. The ingredients of the solution may affect the concentrations of OH and H2O2. Addition of 0.1% O(2)generates strongest OH emission above surfaces of plasma-treating solution with our He-APPJ, and thus, the highest H(2)O(2)concentration in PTM. The MCF7 cell viability is influenced by the H(2)O(2)concentration in PTM. The results of this study can facilitate further study of plasma effects on PTM and cell culture.
Atomic Oxygen and Hydroxyl Radical Generation in Round Helium-Based Atmospheric-Pressure Plasma Jets by Various Electrode Arrangements and Its Application in Sterilizing Streptococcus mutans
(2014-12-01)
Liu, Chih-Tung
;
Wu, Ching-Jung
;
Yang, Yi-Wei
;
Lin, Zhi-Hua
;
Wu, Jong-Shinn
The reactive chemical species generated in an atmospheric-pressure plasma jet (APPJ), such as hydroxyl radical and atomic oxygen, are generally regarded as the major sources for several biomedical applications. In this paper, we propose an APPJ with a 25-kHz high-voltage powered stainless steel tube fixed inside a quartz tube and an aluminum grounded electrode that is wrapped around the quartz tube. The results show that the radical intensities of atomic oxygen and hydroxyl radical, gas temperature, and power absorption increase with increasing distance of discharge gap distance under the same applied voltage. Increasing the width of grounded electrode increases gas temperature and causes higher power absorption but only slight change of radical generation. We have applied the APPJ with the conditions of highest radical generation (grounded electrode width = discharge gap distance = 15 mm) for effectively sterilizing Streptococcus mutans within 15 s, which shows a highly potential application for root canal disinfection.
Capturing H and H-2 by SiHx+ (x <= 4) ions: Comparison between Langevin and quantum statistical models
(2017-02)
Trong-Nghia Nguyen
;
Lee, Yun-Min
;
Wu, Jong-Shinn
;
Lin, Ming-Chang
;
機械工程學系
H, H-2, and SiHx+ (x <= 4) ions coexist under plasma-enhanced chemical vapor deposition (PECVD) conditions. We have studied the kinetics of their interactions by high-level quantum chemical and statistical theory calculations, and compared the results with classical Langevin values (similar to 2 x 10(-9)cm(3) molecule(-1) s(-1) independent of temperature). The results indicate that, for H capturing by SiHx+ (x <= 4), both theories agree within a factor of 2-4, whereas for H-2 capturing by SiHx+ (x <= 3), the modern theory gives higher and weakly temperature-dependent values by up to more than one order of magnitude, attributable to reaction path degeneracies and increased entropies of activation. The heats of formation and structural parameters of SiHx+ ions (x <= 5) in this work agree well with available experimental data. For practical applications, we have provided tables of rate constants for modeling various processes of relevance to the PECVD of a-Si: H films. (C) 2017 The Japan Society of Applied Physics
CHARACTERIZATION OF A NITROGEN-BASED PLANAR DBD APPJ AND ITS APPLICATION IN ITO GLASS CLEANING
(2009)
Chiang, Ming-Hung
;
Lin, I-Min
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Lu, Chi-Chang
;
Huang, Hao-Yuan
;
Wu, Jong-Shinn
A parallel-plate dielectric barrier discharge (DBD) driven by a quasi-pulsed power supply (60 kHz) under atmospheric-pressure condition was developed and characterized. Various types of working gases, including pure nitrogen, various ratios of volume flow rates of nitrogen to oxygen and compressed air, were tested and compared. A colorful planar jet plume up to 50 mm wide, 25 mm long and gas temperature of 330K was formed at the exit of the parallel-plate channel for both pure and oxygen-traced nitrogen jets. OES measurements in the post-discharged nitrogen jet region showed that UV intensities increase dramatically with trace addition of oxygen (e.g., 1/1000) as compared to the pure nitrogen case. The post-discharge jet region was applied to improve the hydrophilicity of a moving ITO glass surface. Results showed that the measured contact angle of ITO glass surface can reduce from 84 to 26 degrees with a relative moving speed of 9 cm/s.
Deposition of Hydroxyl Functionalized Films by Means of ethylene Aerosol-Assisted Atmospheric Pressure Plasma
(2014-11-01)
Yang, Yi-Wei
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Camporeale, Giuseppe
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Sardella, Eloisa
;
Dilecce, Giorgio
;
Wu, Jong-Shinn
The atmospheric pressure plasma deposition of hydroxyl functionalized hydrocarbon films is reported in this work, with a reactor fed with water aerosol and ethylene. The effects of power and feed flow rates onto film chemistry have been investigated. Coatings produced with this approach can find application in the biomedical field, among others, as platforms for cell adhesion and proliferation. Results show that operating at 4 kHz provides a much higher amount of hydroxyl group in the coating compared with samples obtained at 11 kHz. After water immersion, the stability of the films and their amount of hydroxyl groups remain high. A simplified deposition mechanism is proposed.
DEVELOPMENT AND CHARACTERIZATION OF A PORTABLE ATMOSPHERIC-PRESSURE ARGON PLASMA JET FOR STERILIZATION
(2016)
Lin, Zhi-Hua
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Wu, Jong-Shinn
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Tschang, Chen-Yon Tobias
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Su, Chi-Feng
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Wu, Tuoh
In this study, we would like to develop a portable round argon atmospheric-pressure plasma jet (APPJ) which can be applied for general use of bacteria inactivation. The APPJ was characterized electrically and optically, which include measurements of absorption power, gas temperature and optical properties of plasma generated species. Measured OH* number density at 5 mm downstream was estimated to be 5.8 x 10(15) cm(3) and the electron density and electron temperature were estimated to be 2.4 x 10(15) cm(-3) and 0.34 eV, respectively, in the discharge region. This APPJ was demonstrated to effectively inactivate E. coli within seconds of treatment, which shows its great potential in the future use of general bacteria inactivation and sterilization.
Development of a parallel implicit solver of fluid modeling equations for gas discharges
(2011-01-01)
Hung, Chieh-Tsan
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Chiu, Yuan-Ming
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Hwang, Feng-Nan
;
Wu, Jong-Shinn
;
機械工程學系
A parallel fully implicit PETSc-based fluid modeling equations solver for simulating gas discharges is developed Fluid modeling equations include the neutral species continuity equation the charged species continuity equation with drift-diffusion approximation for mass fluxes the electron energy density equation and Poisson s equation for electrostatic potential Except for Poisson s equation all model equations are discretized by the fully implicit backward Euler method as a time integrator and finite differences with the Scharfetter-Gummel scheme for mass fluxes on the spatial domain At each time step the resulting large sparse algebraic nonlinear system is solved by the Newton-Krylov-Schwarz algorithm A 2D-GEC RF discharge is used as a benchmark to validate our solver by comparing the numerical results with both the published experimental data and the theoretical prediction The parallel performance of the solver is investigated (C) 2010 Elsevier B V All rights reserved
Development of a parallelized 2D/2D-axisymmetric Navier-Stokes equation solver for all-speed gas flows
(2011-06-01)
Hu, Meng-Hua
;
Wu, Jong-Shinn
;
Chen, Yen-Sen
;
機械工程學系
;
Department of Mechanical Engineering
A parallelized 2D/2D-axisymmetric pressure-based, extended SIMPLE finite-volume Navier-Stokes equation solver using Cartesians grids has been developed for simulating compressible, viscous, heat conductive and rarefied gas flows at all speeds with conjugate heat transfer. The discretized equations are solved by the parallel Krylov-Schwarz (KS) algorithm, in which the ILU and BiCGStab or GMRES scheme are used as the preconditioner and linear matrix equation solver, respectively. Developed code was validated by comparing previous published simulations wherever available for both low- and high-speed gas flows. Parallel performance for a typical 2D driven cavity problem is tested on the IBM-1350 at NCHC of Taiwan up to 32 processors. Future applications of this code are discussed briefly at the end. (C) 2010 Elsevier Ltd. All rights reserved.
Development of a semi-implicit fluid modeling code using finite-volume method based on Cartesian grids
(2011-01-01)
Smith, Matthew R.
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Hung, Chieh-Tsan
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Lin, Kun-Mo
;
Wu, Jong-Shinn
;
Yu, Jen-Perng
Presented is the HLLG (Harten Lax and van Leer with Gradient inclusion) method for application to the numerical solution of general Partial Differential Equations (PDEs) in conservation form The HLLG method is based on the traditional HLL method with formal mathematical inclusion of gradients of conserved properties across the control volume employed for flux derivation The simple extension demonstrates that conventional higher extensions of the HLL method are mathematically inconsistent and produce various numerical instabilities The HLLG method with higher order extensions consistent with the flux derivation is absent of (or less affected by) the said numerical instabilities The HLLG method is then applied to solutions of the Euler Equations and the simulation of ID argon RF plasma simulation (C) 2010 Elsevier B V All rights reserved
Direct Plasma Deposition of Lysozyme-Embedded Bio-Composite Thin Films
(2015-11-01)
Palumbo, Fabio
;
Camporeale, Giuseppe
;
Yang, Yi-Wei
;
Wu, Jong-Shinn
;
Sardella, Eloisa
Bio-composite coatings, consisting of an organic matrix embedding a bioactive molecule, have been deposited by means of atomizer-assisted atmospheric pressure plasma. Ethylene was chosen as the precursor of the matrix, while the atomizer was fed with a water solution of lysozyme. Coatings chemical composition was investigated by XPS, FTIR and MALDI-TOF spectroscopies, and it has been proved that the one-step inclusion of protein domains in the composite coatings is successful and lysozyme chemical structure is only slightly altered. The amount of embedded lysozyme is as high as 14 mg/cm(2) as evaluated from water release test. Finally, the activity of the plasma-embedded protein is close to that of pure lysozyme as verified against Micrococcus lysodeikticus ATCC 4698 through an agar plate diffusion test.
Direct Plasma Deposition of Lysozyme-Embedded Bio-Composite Thin Films
(2015-11)
Palumbo, Fabio
;
Camporeale, Giuseppe
;
Yang, Yi-Wei
;
Wu, Jong-Shinn
;
Sardella, Eloisa
Bio-composite coatings, consisting of an organic matrix embedding a bioactive molecule, have been deposited by means of atomizer-assisted atmospheric pressure plasma. Ethylene was chosen as the precursor of the matrix, while the atomizer was fed with a water solution of lysozyme. Coatings chemical composition was investigated by XPS, FTIR and MALDI-TOF spectroscopies, and it has been proved that the one-step inclusion of protein domains in the composite coatings is successful and lysozyme chemical structure is only slightly altered. The amount of embedded lysozyme is as high as 14 mg/cm(2) as evaluated from water release test. Finally, the activity of the plasma-embedded protein is close to that of pure lysozyme as verified against Micrococcus lysodeikticus ATCC 4698 through an agar plate diffusion test.