AIP Conference Proceedings Research Articles

RESEARCH PRODUCTIVITY OF PANDIT DEENDAYAL PETROLEUM UNIVERSITY AT GANDHINAGAR DURING 2008-2019: A BIBLIOMETRIC STUDY

This study endeavours to embrace a bibliometric analysis of the research publications of Pandit Deendayal Petroleum University (PDPU) from 2008-2019. It is in this context that the present study aims to audit the exploration execution the research performance of PDPU based on the papers published in journals that have indexed in Scopus for as far back as eleven years. The total number of 931 publications has retrieved from the Scopus database. Amongst them, 64.44 % are research articles published in scholarly journals and 28.89 % in Conference proceedings. The paper also analyzed the publication trend of Pandit Deendayal Petroleum University and found that from 2008 onwards there was a steady increase in the number of publications. The authors attempt to identify the current trends in research output by PDPU, which includes the most prolific authors, institutional collaborative works, research productivity in terms of publications, highest citations papers, most preferred publications, etc.… The research publications was found highest numbers of publications in the year 2019. Findings of this study also reveal that the “AIP Conference Proceedings” is the most preferred journal, and Mukhopadhyay, I, is the most prolific author and has made the highest number of publications.

(Invited) Second Harmonic Generation: A Powerful Non-Destructive Characterization Technique for Dielectric-on-Semiconductor Interfaces

The quality of interfaces between dielectrics and semiconductors has a tremendous impact on the performances of semiconductor devices. High-k dielectrics are omnipresent in the gate stack of advanced MOSFETs. They are also used as passivation layers for silicon in fields such as solar cells [1] or image sensors [2]. When referring to passivation, two mechanisms can be identified: chemical passivation (quantified by the interface state density, Dit) and electric-field passivation (quantified by fixed oxide charge density, Qox). An ideal characterization method for passivated silicon should give access to both chemical and field-effect relevant quantities (ideally being able to distinguish them) in a non-destructive way. Among the commonly used techniques, we can cite electrical methods based on current or capacitance monitoring of simple test devices [3], Corona characterization of semiconductors [4], carrier lifetime extraction [5] conducted through photoconductance or photoluminescence decay measurements, etc. The choice among these several options is based on criteria such as sensitivity, non-destructiveness, possibility of direct on-wafer probing without any additional device fabrication steps, ability to discriminate Dit and Qox, capability to provide a high spatial resolution. A recent technique which could meet all these criteria is the second harmonic generation (SHG) [6], provided that an appropriate calibration method is developed for Dit and Qox extraction.The SHG is a non-linear optics phenomenon: when a high intensity laser beam of wavelength λ reaches a sample, a second harmonic wave at λ/2 is generated by the sample. For centrosymmetric materials (such as silicon, SiO2, Al2O3, etc.) the SHG signal contains two parts: one related to the symmetry breaking inherently present at interfaces between two different materials, and another one produced by any “static” electric field in the sample [7]. Such field is present at the vicinity of dielectric-to-semiconductor interfaces due to charge trapping by various mechanisms. In other words, the magnitude of the generated SHG signal contains information on both Dit and Qox This technique has already been used for dielectric characterization with various modalities (SHG versus power, time, wavelength ...) [8], [9], [10].The SHG proved very promising (sensitive, non-destructive, applied directly on-wafer, etc.); however its extensive use still needs a more general calibration methodology. Such a methodology requires not only SHG measurements, but also real Qox/Dit values extracted by classical electrical methods on the same samples and modeling to understand/anticipate the expected effect of these parameters on the SHG signal. In this paper, we’ll discuss all these issues based on a review of our recent advances on how to exploit SHG for dielectrics on semiconductor characterization.AcknowledgementsThis work was supported by Region Rhône Alpes (ARC6 program), the French National Research Agency within the framework of the OXYGENE project (ANR-17-CE05-0034) and French National Plan Nano2022, within the IPCEI Nanoelectronics for Europe program.[1] A. G. Aberle, "Surface passivation of crystalline silicon solar cells: a review," Progress in Photovoltaics: Research and Applications, vol. 8, pp. 473-487, 2000.[2] J. L. Regolini, D. Benoit, and P. Morin, "Passivation issues in active pixel CMOS image sensors," Microelectronics Reliability, vol. 47, pp. 739-742, 2007.[3] D. K. Schroder, Semiconductor Material and Device Chracterization, 3rd Edition ed. New Jersey: John Wiley & sons, 2006.[4] M. Wilson, J. Lagowski, L. Jastrzebski, A. Savtchouk, and V. Faifer, "COCOS (corona oxide characterization of semiconductor) non-contact metrology for gate dielectrics," AIP Conference Proceedings, vol. 550, pp. 220-225, 2001.[5] D. K. Schroder, "Carrier lifetimes in silicon," Electron Devices, IEEE Transactions on, vol. 44, pp. 160-170, 1997.[6] G. Lupke, "Characterization of semiconductor interfaces by second-harmonic generation," Surface Science Reports, vol. 35, pp. 75-161, 1999.[7] J. E. Sipe, D. J. Moss, and H. M. van Driel, "Phenomenological theory of optical second- and third-harmonic generation from cubic centrosymmetric crystals," Physical Review B, vol. 35, pp. 1129-1141, 1987.[8] J. Price, M. Lei, P. S. Lysaght, G. Bersuker, and M. C. Downer, "Charge trapping defects in Si/SiO2/Hf(1−x)SixO2 film stacks characterized by spectroscopic second-harmonic generation," Journal of Vacuum Science & Technology B, vol. 29, p. 04D101, 2011.[9] N. M. Terlinden, G. Dingemans, V. Vandalon, R. H. E. C. Bosch, and W. M. M. Kessels, "Influence of the SiO2 interlayer thickness on the density and polarity of charges in Si/SiO2/Al2O3 stacks as studied by optical second-harmonic generation," Journal of Applied Physics, vol. 115, p. 033708, 2014.[10] H. Park, J. Qi, Y. Xu, K. Varga, S. M. Weiss, B. R. Rogers, et al., "Boron induced charge traps near the interface of Si/SiO2 probed by second harmonic generation," Physica Status Solidi (b), vol. 247, pp. 1997-2001, 2010.

Polytropic Coefficient Function for Tonks-Langmuir-Type Bounded Plasmas with Kappa-Distributed Electrons and Cold Ion Source

In the fluid description of the classical Tonks-Langmuir (TL) model [Tonks and Langmuir, Phys Rev., 34: 876, 1929], arises the “closure problem.” The continuity and the momentum equations need, in addition, a closure equation. Usually, this closure equation assumes zero ion pressure (pi = 0), or a constant ion polytropic coefficient (γi). These simplified assumptions are likely to produce incorrect results, because (i) the ions have a non-zero temperature, even if the ion source is assumed to be cold, and (ii) the polytropic coefficient is, in fact, a function of space (or potential), and is far from constant (Kuhn et al., AIP Conference Proceedings, 1306: 216, 2010). Here, the concept of polytropic coefficient function (PCF) is applied to a TL-type discharge with a Kappa-distributed ion source. The ion density and temperature are calculated numerically, for different values of the spectral index κ. The polytropic coefficient function is then calculated using the relation γ = 1 + (n/T) (dT/dn). Striking deviation from results of the classical case are observed. It is shown here that, for Kappa-distributed ion sources, the ion PCF is not a constant, but is a function of the potential. Moreover, the sheath-edge potential differs significantly from the classical case. It is concluded that in order to close the set of fluid equations in an appropriate manner, better approximations to the PCF are needed.

Research Output of Guru Jambheshwar University of Science and Technology during 1999–2018: A Bibliometric Study

The present study explores bibliometric analysis of the research output of Guru Jambheshwar University of Science and Technology during 1999-2018. The data was extracted from SCOPUS database and produced a total of 2072 publications that were recognized to authors affiliated to GJUST 11.31 %) was the most favored subject category among authors. GJUS&T has the maximum number of collaborative scientific papers (137) with Maharshi Dayanand University, Rohtak. The most preferred journal for publication was AIP conference proceedings. Ashish Agarwal from Applied Physics department was identified as the most productive author with 155 publications, whereas V.K Garg from the department of Environmental Science & Engineering had the highest h-index (41) and average citation per paper (46.17) as well.

On the numerical investigations to the Cahn-Allen equation by using finite difference method

In this study, by using the finite difference method (FDM for short) and operators, the discretized Cahn-Allen equation is obtained. New initial condition for the Cahn-Allen equation is introduced, considering the analytical solution given in Application of the modified exponential function method to the Cahn-Allen equation, AIP Conference Proceedings 1798, 020033 [1]. It is shown that the FDM is stable for the usage of the Fourier-Von Neumann technique. Accuracy of the method is analyzed in terms of the errors in and Furthermore, the FDM is treated in order to obtain the numerical results and to construct a table including numerical and exact solutions as well as absolute measuring error. A comparison between the numerical and the exact solutions is supported with two and three dimensional graphics via Wolfram Mathematica 11.

(Invited) Electrodeposition of Copper and Cobalt in Presence of Some Organic Additives

Electroplated damascene copper has been used for more than 20 years for interconnects in semiconductor and microelectronic industry1. As the structures continue to scale, the coarse grains formed during annealing become increasingly difficult to extend into the fine structures, resulting in higher resistance and poorer electro-migration. While such difficulty in grain growth relates to the geometrical confinement of fine structures itself, the impurity incorporation from organic additives used in electrolyte was also found much higher2, 3 and is expected to impede the grain growth4. However, impurity elements such as carbon, oxygen, sulfur, and chloride are typically incorporated together and increase or decrease simultaneously. The first part of this talk presents a study where we used ion implantation to dissect the effects of each elements separately, aiming to identify the elements that have the dominant effect on copper grain growth. The different copper grain growth behaviors in presence of different impurity elements will be discussed. Figure 1 shows the top down focus ion beam image of copper films implanted with the same amount of chlorine and carbon after annealing at different temperatures. While both elements impeded copper grain growth compared with as-plated copper, a stronger inhibition effect in the nucleation of coarse grains at low temperature was observed for chlorine. However, an instantaneous nucleation followed by a more abnormal grain growth was observed for chlorine, resulting in a fully transformed film with uniform grain size at 400 C. On the other hand, carbon continue to inhibit the grain nucleation at high temperature and the film was only partially transformed even at a high temperature of 400 C. On the second part of the talk, electrodeposition of cobalt in presence of a class of additives, dioxime, will be presented. Copper suffers a rapid increase in its resistivity when the critical dimension of structures falls below the electron mean free path of copper, 38 nm5. On the other hand, cobalt is of interest as a candidate to replace copper in the metallization because of its much shorter electron mean free path of 7 to 11 nm6. The presence of dimethylglyoxime was found to suppress cobalt electrodeposition, which makes it of interest for metallization. Various of dioxime molecules are characterized and compared. A surface adsorbed complexed species between cobalt cation and oxime is proposed to result in the suppression. REFERENCES P. Andricacos, C. Uzoh, J. Dukovic, J. Horkans and H. Deligianni, IBM Journal of Research and Development, 42, 567-574 (1998).J. Kelly, T. Nogami, O. Van der Straten, J. Demarest, J. Li, C. Penny, T. Vo, C. Parks, P. DeHaven and C.-K. Hu, Journal of The Electrochemical Society, 159, D563-D569 (2012).Q. Huang, A. Avekians, S. Ahmed, C. Parks, B. Baker-O'Neal, S. Kitayaporn, A. Sahin, Y. Sun and T. Cheng, Journal of The Electrochemical Society, 161, D388-D394 (2014).C. K. Hu, M. Angyal, B. C. Baker, G. Bonilla, C. Cabral, D. F. Canaperi, S. Choi, L. Clevenger, D. Edelstein and L. Gignac, Proceedings of AIP Conference Proceedings, pp. 57, 2010.J. VanOlmen, S. List, Z. Tokei, L. Carbonell, S. Brongersma, H. Volders, E. Kunnen, N. Heylen, I. Ciofi and A. Khandelwal, Proceedings of 2007 IEEE International Interconnect Technology Conferencee, pp. 49-51, 2007.D. Gall, Journal of Applied Physics, 119, 085101 (2016). Figure 1

Differential Pulse Voltammetry of Nitrobenzene

Removal of nitrobenzene from water is of current interest due to its toxicity (1) as a mutagen and carcinogen. Water sample with initial known concentration of nitrobenzene (4mM) was taken and treated with adsorbent: spent tea leaves (2). After treatment with adsorbent nitrobenzene was analyzed using such electrochemical techniques (3) as differential pulse, Figure 1, and square wave voltammetry (curve not shown) to obtain a calibration curve for quantitative estimation of nitrobenzene. Cyclic voltammetry was employed for preliminary work (4). A calculated amount of cetyltrimethylammonium bromide (CTAB) was added to a specific volume of all nitrobenzene solutions as the supporting electrolyte. All analyses were carried out in 0.1 M aqueous CTAB at a platinum cathode using EG&G VersaStat II. This study shows that spent tea leaves can be effectively used for the removal of nitrobenzene from aqueous solutions. A substantial decrease in the concentration of nitrobenzene was observed after treating 100 mL of 4mM nitrobenzene solution with different weighed amounts of adsorbent (spent tea leaves) when a contact time of one hour was allowed, Figure 1. References (1) A. Hartwig, The MAK-Collection for Occupational Health and Safety, pp.1473-1544 (2017) DOI: 10.1002/3527600418.mb33341e5917 (2) E. Heraldy, R. R. Osa and V. Suryanti, AIP Conference Proceedings, 1710, 030025 (2016) (3) S. Manivannan, J. Jeong, D.-K. Kang, and K. Kim, Electroanalysis (2017) DOI:10.1002/elan.201700451 (4) I. U. Haque, AASCIT Journal of Materials (2017) Figure 1

On almost B-summable double sequence spaces

The concept of a four-dimensional generalized difference matrix and its domain on some double sequence spaces was recently introduced and studied by Tuğ and Başar (AIP Conference Proceedings, vol. 1759, 2016) and Tuğ (J. Inequal. Appl. 2017(1):149, 2017). In this present paper, as a natural continuation of (J. Inequal. Appl. 2017(1):149, 2017), we introduce new almost null and almost convergent double sequence spaces B(mathcal{C}_{f}) and B(mathcal{C}_{f_{0}}) as the four-dimensional generalized difference matrix B(r,s,t,u) domain in the spaces mathcal{C}_{f} and mathcal{C}_{f_{0}}, respectively. Firstly, we prove that the spaces B(mathcal{C}_{f}) and B(mathcal{C}_{f_{0}}) of double sequences are Banach spaces under some certain conditions. Then we give an inclusion relation of these new almost convergent double sequence spaces. Moreover, we identify the α-dual, beta(bp)-dual and γ-dual of the space B(mathcal{C}_{f}). Finally, we characterize some new matrix classes (B(mathcal{M}_{u}):mathcal{C}_{f}), (mathcal{M}_{u}:B(mathcal {C}_{f})), and we complete this work with some significant results.

The Taylor–Melcher leaky dielectric model as a macroscale electrokinetic description

While the Taylor–Melcher electrohydrodynamic model entails ionic charge carriers, it addresses neither ionic transport within the liquids nor the formation of diffuse space-charge layers about their common interface. Moreover, as this model is hinged upon the presence of non-zero interfacial-charge density, it appears to be in contradiction with the aggregate electro-neutrality implied by ionic screening. Following a brief synopsis published by Baygents & Saville (Third International Colloquium on Drops and Bubbles, AIP Conference Proceedings, vol. 7, 1989, American Institute of Physics, pp. 7–17) we systematically derive here the macroscale description appropriate for leaky dielectric liquids, starting from the primitive electrokinetic equations and addressing the double limit of thin space-charge layers and strong fields. This derivation is accomplished through the use of matched asymptotic expansions between the narrow space-charge layers adjacent to the interface and the electro-neutral bulk domains, which are homogenized by the strong ionic advection. Electrokinetic transport within the electrical ‘triple layer’ comprising the genuine interface and the adjacent space-charge layers is embodied in effective boundary conditions; these conditions, together with the simplified transport within the bulk domains, constitute the requisite macroscale description. This description essentially coincides with the familiar equations of Melcher & Taylor (Annu. Rev. Fluid Mech., vol. 1, 1969, pp. 111–146). A key quantity in our macroscale description is the ‘apparent’ surface-charge density, provided by the transversely integrated triple-layer microscale charge. At leading order, this density vanishes due to the expected Debye-layer screening; its asymptotic correction provides the ‘interfacial’ surface-charge density appearing in the Taylor–Melcher model. Our unified electrohydrodynamic treatment provides a reinterpretation of both the Taylor–Melcher conductivity-ratio parameter and the electrical Reynolds number. The latter, expressed in terms of fundamental electrokinetic properties, becomes $O(1)$ only for intense applied fields, comparable with the transverse field within the space-charge layers; at this limit the asymptotic scheme collapses. Surface-charge advection is accordingly absent in the macroscale description. Owing to the inevitable presence of (screened) net charge on the genuine interface, the drop also undergoes electrophoretic motion. The associated flow, however, is asymptotically smaller than that corresponding to the Taylor–Melcher circulation. Our successful matching procedure contrasts the analysis of Baygents & Saville, who considered more general electrolytes and were unable to directly match the inner and outer regions. We discuss this difference in detail.

Linear and Quasi-linear Spaces of Interval Maps

Interval-valued functions, or briefly interval functions, are traditionally associated with numerical analysis and validated computing, see for instance [4, 5]. Such maps also occur naturally as mathematical tools for modeling phenomena where uncertainty is present, such as in biological dynamical systems [3]. Recently interval functions have also been applied to problems in pure mathematics, such as the Dedekind order completion of spaces of continuous functions [1]. In [2] the structure of a linear space was introduced on the set of finite Hausdorff continuous interval functions with domain an open subset of Euclidean space R^n. In this paper we generalize this result to the case of functions defined on an arbitrary topological space. It should be noted that the problem of defining algebraic operations on spaces of interval functions is nontrivial, due to the fact that the set of compact intervals in R is not a group with respect to the Minkowski sum. [1] R. Anguelov R, S. Markov, B. Sendov, The set of Hausdorff continuousfunctions — the largest linear space of interval functions, ReliableComputing 12 (2006) 337 – 363. [2] R. Anguelov R, S. Markov, B. Sendov, The set of Hausdorff continuous functions - the largest linear space of interval functions, Reliable Computing 12 (2006) 337 - 363. [3] S. Markov, Biomathematics and interval analysis: a prosperous marriage, In: M. D. Todorov, Ch. I. Christov, Eds., AIP ConferenceProceedings, Vol. 1301, Amitans’2010, American Institute of Physics,Melville, New York, 2010, pp. 26–36. [4] R. E. Moore, Methods and Applications of Interval Analysis, SIAM,Philadelphia, 1979. [5] B. Sendov, Hausdorff Approximations, Kluwer, Dordrecht, 1990.

Ultra-fast in vivo x-ray microtomography of blowfly wingbeat

Ultra-fast in vivo x-ray microtomography of blowfly wingbeat

ENGLISH

The present study attempts to highlight quantitatively the growth and development of world literature on nuclear waste management in terms of publication output as per international nuclear information system (INIS) database. During 1970-2009, a total of 44529 publications were published by the scientists in the field of nuclear waste management. The average number of publications published per year was 1113. The highest number of publications (2795) were published in 2001. The spurt in the literature output was reported during 1991.2007. There were 140 countries involved in research in this field. The USA topped the list with 6672 (14.98 %) publications followed by Japan with 2859 (6.42 %) publications and France with 2612 (5.87 %). Authorship and collaboration trend was towards multi-authored as more than 56 per cent of the publications were collaborative in nature. An intensive collaboration was found during 2000.2004. Maximum publications were from the domains, nuclear fuel processing and waste management aspect with 29159 publications followed by nuclear installations/reactors with 4188 publications and chemical analysis with 2452 publications. Japan Atomic Energy Agency (Japan) topped the list with 677 publications followed by Bhabha Atomic Research Centre (India) with 533 publications. The most preferred journals by the scientists were: Transactions of the American Nuclear Society with 528 publications, Atw Internationale Zeitschrift fuer Kernenergie with 244 publications, AIP Conference Proceedings with 238 publications. English was the most predominant language (79.56 %) used by the scientists for communication. http://dx.doi.org/10.14429/djlit.31.6.1321

Modelling and Simulation of Phased Array Transducers Base on Advanced UT Techniques

Removed due to plagiarism The original research was published as: SIMULATION OF ADVANCED UT PHASED ARRAY TECHNIQUES WITH MATRIX PROBES AND DYNAMIC SETTINGS FOR COMPLEX COMPONENT INSPECTIONS <https://apps.webofknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=4&SID=U2SJlTPsegzt99T6d6T&page=2&doc=20> By: Chatillon, S.; Mahaut, S.; Dubois, P. Edited by: Thompson, DO; Chimenti, DE Conference: 35th Annual Review of Progress in Quantitative Nondestructive Evaluation Location: Univ Chicago, Chicago, IL Date: JUL 20-25, 2008 REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 28A AND 28B Book Series: AIP Conference Proceedings Volume: 1096 Pages: 864-871 Published: 2009

The Bernoulli Equation and the Poloidal-sonic Singularity in an Inverse Aspect-ratio Expansion Formulation of Equilibria with Flow

Fluid flow can play a significant role in plasma equilibrium, possibly producing transport barriers and profile pedestals. To be consistent with hot ions, finite Larmor radius (FLR) effects should be included. Ito and Nakajima have developed a formulation for calculating magnetohydrodynamic (MHD) equilibria with poloidal-sonic flow and FLR effects using an inverse aspect-ratio expansion, known as the “Ito formulation” [A. Ito and N. Nakajima, AIP Conference Proceedings 1069, 121 (2008)]. The Ito formulation typically possess a singularity when the poloidal flow varies from sub- to super-poloidal sonic, known as the “poloidal-sonic (PS) singularity.” The presence of the PS singularity prevents the Ito formulation from being directly applied to equilibria with such flows. An investigation of the single-fluid MHD model shows that the PS singularity is due to an inverse aspect-ratio expansion of the Bernoulli equation. This suggests that, in order to use the Ito formulation for an accurate calculation of MHD equilibria with poloidal-sonic flows, the Bernoulli equation must be handled non-linearly near the singularity.

Wave Propagation in Coarse Grain Structure in UT Inspection

Removed due to plagiarism The original research was published as: MODELING OF ULTRASONIC PROPAGATION IN A COARSE GRAIN STRUCTURE <https://apps.webofknowledge.com/full_record.do?product=UA&search_mode=GeneralSearch&qid=2&SID=Z1pJDVNJsjgeYkWdsdi&page=2&doc=15> By: Jenson, F.; Fortuna, T.; Doudet, L. Edited by: Thompson, DO; Chimenti, DE Conference: 35th Annual Review of Progress in Quantitative Nondestructive Evaluation Location: Univ Chicago, Chicago, IL Date: JUL 20-25, 2008 REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION, VOLS 28A AND 28B Book Series:AIP Conference Proceedings Volume: 1096 Pages: 1201-1208 Published: 2009

Challenges in Self-Consistent Full-Wave Simulations of Lower Hybrid Waves

Analysis of wave propagation in the lower hybrid range of frequencies (LHRF) in the past was done using ray tracing and the Wentzel-Kramers-Brillouin approximation taking advantage of the very small scale of those waves. To include the effects of wave diffraction and focusing in this regime, full-wave simulation is necessary but requires significantly more computational power. In both ray tracing and full-wave simulations in the LHRF, it is also essential to include the self-consistent evolution of the electron distribution in response to the waves. This adds a considerable computational burden in constructing the stiffness matrix for the system [Valeo , “Full-wave Simulations of LH wave propagation in toroidal plasma with non-Maxwellian electron distributions,” 18th Topical Conference on Radio Frequency Power in Plasmas, AIP Conference Proceedings (2007)]. Advances in algorithms and the availability of massively parallel computer architectures have permitted the solving of the Maxwell-Vlasov system for wave propagation directly [Wright , Phys. Plasmas (2009), 16, July]. We will discuss the various modeling advances that have led to this capability, including various memory-management approaches, physics-motivated algorithm adaptions appropriate to the LHRF, and improvements in the matrix solver to minimize communication overhead when using thousands of cores on leadership-class computer platforms. Of particular importance have been the use of verification and validation techniques and the analytic approximations to the imaginary (pole residue) contribution to the plasma dielectric response.

Possible Physical Mechanisms in the Galaxy to Cause Homochiral Biomaterials for Life

The origin of homochirality in life remains a mystery that some believe is essential for life, and which may result from chiral symmetry breaking interactions with galactic organic material.

Hopf bifurcation of a bacteria-immunity system with delayed quorum sensing

On the basis of Zhang’s model (see [P. Fergola, J. Zhang, M. Cerasuolo, Z.E. Ma, On the influence of quorum sensing in the competition between bacteria and immune system of invertebrates, in: Collective Dynamic: Topics on Competition and Cooperation in the Biosciences: A Selection of Papers in the Proceedings of the BIOCOMP2007 International Conference, AIP Conference Proceedings, vol. 1028, 2008, pp. 215–232] for more details), we formulate a bacteria-immunity model to describe the competition between bacteria and immune cells with bacterial quorum sensing mechanism. A time delay is introduced to characterize the time in which bacteria receive signal molecules and then combat with immune cells. Subsequently, the length of delay which preserves the stability of the positive equilibrium is estimated and Hopf bifurcation occurs when time delay crosses through a critical value are researched. Further, by using the normal form theory and center manifold theory, the explicit formulaes are calculated which determine the stability, the direction and the period of bifurcating periodical solutions. Finally, numerical simulations are employed to verify the mathematical conclusions.

Possibility of resonant capture of antiprotons by highly charged hydrogenlike ions

Recently, an experimental setup was proposed by Lapierre et al. [Physics with ultra slow antiproton beams, AIP Conference Proceedings (2005), Vol. 793, p. 361] which would allow antiprotons and highly charged ions to collide repeatedly in an electron beam ion trap (EBIT) due to a nested trap configuration. As mentioned by the authors, such a setup may open the possibility to study antiproton capture into well-defined states through a resonant process which involves simultaneous electron excitation. In the present work, we give some theoretical estimations of the feasibility of that process.

Vibration–rotation–translation spectrum of molecular hydrogen in fullerite lattices around 80K

Abstract Calculations are presented for the fundamental vibration–rotation spectrum of H 2 in fcc C 60 (fullerite) lattices near 80 K using the approach and the parameters used by Herman and Lewis [Phys. Rev. B 73 (2006) 155408; in: E. Oks, M. Pindzola (Eds.) Spectral Line Shapes, AIP Conference Proceedings, No. 874, American Institute of Physics, 2006, pp. 162–176 (Proceedings of the 18th ICSLS)] at 293 K. Good agreement is found with recent drift spectra of FitzGerald et al. [Personal communication, 2006]. It is argued that our approach cannot be extended to the 10 K spectrum without significant modification.