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1

Electronic Resource

Semianalytical ion current model for radio-frequency driven collisionless sheaths (2001)

Bose, Deepak

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 89 (2001), S. 5932-5938

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ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: We propose a semianalytical ion dynamics model for a collisionless radio-frequency biased sheath. The model uses bulk plasma and electrode boundary conditions to predict the ion impact energy distribution and electrical properties of the sheath. The proposed model accounts for ion inertia and ion current modulation at bias frequencies that are of the same order of magnitude as the ion plasma frequency. A relaxation equation for ion current oscillations is derived, which is coupled with a damped potential equation in order to model ion inertia effects. We find that inclusion of ion current modulation in the sheath model shows marked improvements in the predictions of the sheath electrical properties and ion energy distribution function. © 2001 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.1365436

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2

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Ion dynamics model for collisionless radio frequency sheaths (2000)

Bose, Deepak ; Govindan, T. R. ; Meyyappan, M.

[S.l.] : American Institute of Physics (AIP)

Journal of Applied Physics 87 (2000), S. 7176-7184

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ISSN: 1089-7550

Source: AIP Digital Archive

Topics: Physics

Notes: Full scale reactor model based on fluid equations is widely used to analyze high density plasma reactors. It is well known that the submillimeter scale sheath in front of a biased electrode supporting the wafer is difficult to resolve in numerical simulations, and the common practice is to use results for electric field from some form of analytical sheath model as boundary conditions for full scale reactor simulation. There are several sheath models in the literature ranging from Child's law to a recent unified sheath model [P. A. Miller and M. E. Riley, J. Appl. Phys. 82, 3689 (1997)]. In the present work, the cold ion fluid equations in the radio frequency sheath are solved numerically to show that the spatiotemporal variation of ion flux inside the sheath, commonly ignored in analytical models, is important in determining the electric field and ion energy at the electrode. Consequently, a semianalytical model that includes the spatiotemporal variation of ion flux is developed for use as boundary condition in reactor simulations. This semianalytical model is shown to yield results for sheath properties in close agreement with numerical solutions. © 2000 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.372966

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3

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Thermal rate constants of the N2+O→NO+N reaction using ab initio 3A″ and 3A′ potential energy surfaces (1996)

Bose, Deepak ; Candler, Graham V.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 104 (1996), S. 2825-2833

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ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: Theoretical determinations of the thermal rate constants and product energy distributions of the N2+O→NO+N reaction, which plays a crucial role in hydrocarbon air combustion and high temperature air chemistry, are carried out using a quasiclassical trajectory method. An analytical fit of the lowest 3A′ potential energy surface of this reaction based on the CCI ab initio data is obtained. The trajectory study is done on this surface and an analytical 3A″ surface proposed by Gilibert et al. [J. Chem. Phys. 97, 5542 (1992)]. The thermal rate constants computed from 3000 to 20 000 K are in good agreement with the available experimental data. In addition, the dependence of the rate constant on the N2 internal state is studied. It is found that a low vibrational excitation can reduce the rate constant of this reaction by a factor of 3. Also, we investigate the effect of the N2 vibrational state on the product NO vibrational distribution, and it is found that at low N2 vibrational states, the NO vibrational distribution is nearly Boltzmann. However, at N2(v(approximately-greater-than)10), the product distribution is almost uniform at low energy levels. © 1996 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.471106

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4

Electronic Resource

A multiple translational temperature gas dynamics model (1994)

Candler, Graham V. ; Nijhawan, Sandeep ; Bose, Deepak ; [et al.]

[S.l.] : American Institute of Physics (AIP)

Physics of Fluids 6 (1994), S. 3776-3786

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ISSN: 1089-7666

Source: AIP Digital Archive

Topics: Physics

Notes: Within shock waves, the translational motion of the gas is more energetic in the direction perpendicular to the shock than in the direction parallel to the shock. To represent this translational nonequilibrium, new continuum conservation equations are developed. These equations are derived by solving the Boltzmann equation with a first-order Chapman–Enskog expansion of an anisotropic velocity distribution function. This results in a gas model with anisotropic pressure, temperature, and speed of sound. The governing equations are solved numerically for one-dimensional steady shock waves in a Maxwellian gas. The numerical results are compared to those obtained using the direct simulation Monte Carlo method. The new continuum model captures many of the features of shock waves. In particular, this paper finds that translational nonequilibrium is present at all Mach numbers. For Mach numbers greater than 1.5, the perpendicular temperature overshoots the post-shock temperature. At the point where this temperature reaches a maximum, the model predicts that for any shock wave, the square of the perpendicular-direction Mach number is one-third; this is substantiated by the DSMC results.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.868367

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5

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Thermal rate constants of the O2+N→NO+O reaction based on the A〈sup LOCATION="PRE"〉2′ and A〈sup LOCATION="PRE"〉4′ potential-energy surfaces (1997)

Bose, Deepak ; Candler, Graham V.

College Park, Md. : American Institute of Physics (AIP)

The Journal of Chemical Physics 107 (1997), S. 6136-6145

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ISSN: 1089-7690

Source: AIP Digital Archive

Topics: Physics , Chemistry and Pharmacology

Notes: A detailed quasiclassical trajectory study of the O2+N→NO+O reaction is performed based on ab initio potential-energy surfaces of the 2A′ and 4A′ states. The study is aimed at generating a database of thermally averaged and O2 state-specific rate constants needed for accurate simulations of NO kinetics in high-temperature flow processes. The rate constants obtained show good agreement with the available experimental data and with other quasiclassical trajectory calculations. It is found that the reactant internal energy of the O2+N→NO+O reaction is less effective in enhancing the rate than in theN2+O→NO+N reaction. An analysis of the product vibrational energy shows that NO formed by theO2+N→NO+O reaction has a non-Boltzmann distribution. It is also found that the most populated NO vibrational level is determined by the reactant vibrational energy, while the terminal slope of the NO vibrational distribution is a strong function of the reactant translational temperature. © 1997 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.475132

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6

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Simulation of hypersonic flows using a detailed nitric oxide formation model (1997)

Bose, Deepak ; Candler, Graham V.

[S.l.] : American Institute of Physics (AIP)

Physics of Fluids 9 (1997), S. 1171-1181

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ISSN: 1089-7666

Source: AIP Digital Archive

Topics: Physics

Notes: In this paper the extensive quasiclassical trajectory (QCT) study recently concluded [J. Chem. Phys. 104, 2825 (1996)] is used to model the kinetics of the primary NO formation reaction, N2+O→NO+N, in hypersonic nonequilibrium flows. The QCT data are used to obtain expressions for the thermal rate constant, reactant energy removal, and product energy disposal rates of this reaction. The QCT results are coupled with the continuum conservation flow equations, and these equations are used to simulate the Bow-Shock UltraViolet2 (BSUV2) flow at altitudes between 75 to 87.5 km. It is found that the use of the Macheret and Rich [Chem. Phys. 174, 25 (1993)] vibration–dissociation coupling model along with the QCT rates gives improvements in the NO concentration predictions at altitudes between 80 and 85 km. Also, it is found that the vibrational and rotational temperatures of NO are much higher than that of the N2 and O2 in the gas, in accordance with the BSUV2 measurements. The amount of NO produced in the flow fields at 87.5 km and above is found to be strongly dependent on the free-stream density of atomic oxygen. © 1997 American Institute of Physics.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1063/1.869205

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7

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An endogenous positive inotropic factor (EPIF) from porcine heart: Its effects on sarcoplasmic reticular (SR) Ca2+metabolism (1997)

Khatter, Jagdish C. ; Agbanyo, Moses ; Bose, Deepak ; [et al.]

Springer

Molecular and cellular biochemistry 176 (1997), S. 163-168

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ISSN: 1573-4919

Keywords: endogenous positive inotrope ; porcine heart ; SR

Source: Springer Online Journal Archives 1860-2000

Topics: Biology , Chemistry and Pharmacology , Medicine

Notes: Abstract We have isolated an endogenous positive inotropic factor (EPIF) from porcine left heart ventricular tissue, which demonstrated to have only weak digitalis-like properties including the inhibition of myocardial Na+,K+-ATPase. EPIF completely lacks digitalis-like toxicity such as after-contractions in larger doses. In our recent studies, we have demonstrated that EPIF produces a decrease in the amplitude of the post-rest rapid cooling contracture which indicated that EPIF may release Ca2+from the sarcoplasmic reticulum. In the present study, the effects of EPIF were investigated on the Ca2+uptake and release properties of SR enriched membrane vesicles from rat heart. At pH 6.8 and in the presence of oxalate, EPIF dose-dependently inhibited the ATPdependent uptake of Ca2+by SR vesicles. Concentrations as low as 25 ul (in 1 mL uptake medium) of EPIF caused a 45-47% reduction in the uptake of Ca2+within 3-4 min. Increases in EPIF concentration to 50 ul/mL caused additional reduction of only 15-20% in the uptake of Ca2+. Concentrations of 25 ul/mL of EPIF had little or no effects on passive release of actively loaded Ca2+in SR vesicles. On doubling the concentrations to 50 ul/mL EPIF, however, enhanced the release of Ca2+by 25-28% during 1-2 min. and 44-48% after 4 min of incubation of Ca2+loaded vesicles in the release medium. Relatively smaller effects of EPIF on Ca2+release implies that EPIF may mainly lower the uptake of Ca2+in SR. This reduced uptake of Ca2+may be explained by the EPIF-induced inhibition of Ca2+pump.

Type of Medium: Electronic Resource

URL: http://dx.doi.org/10.1023/A:1006859919764

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