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Wyszukujesz frazę "Bhattacharyya, S." wg kryterium: Autor


Wyświetlanie 1-12 z 12
Tytuł:
Antihydrogen Formation in Low Energy Collision of Positron with Antiproton
Autorzy:
Bhattacharyya, S.
Powiązania:
https://bibliotekanauki.pl/articles/1931542.pdf
Data publikacji:
1994-05
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.50.+a
34.70.+e
39.10.+x
Opis:
In the present paper two-body radiative recombination rate for the production of antihydrogen (H̅) in a merged beam of slow positrons (e$\text{}^{+}$) and antiprotons (p¯) is studied in the light of a two-step process, which consists of capture in an excited state of H̅ with subsequent decay to the ground state and emission of a photon. Computation is done using the field theory and the Coulomb gauge. Importance of the two-step radiative recombination process relative to the well-known spontaneous photorecombination process, on the two-body radiative recombination rate for antihydrogen formation, is discussed. The present result predicts higher contribution from the two-step radiative recombination process as compared to the spontaneous photorecombination process to the rate of cold antihydrogen formation with the relative collision energy below 0.01 Rydberg, near which experiments are being conducted. However, above 0.1 Rydberg the spontaneous photorecombination process dominates over the two-step radiative recombination process. The present result is valid, as well, for the formation of hydrogen atom due to collision between slow electron and proton.
Źródło:
Acta Physica Polonica A; 1994, 86, 3; 297-308
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Angular Differential Cross-Section for Electron Transfer in ION-ION Collision
Autorzy:
Bhattacharyya, S.
Bhattacharyya, S. K.
Mitra, S.
Powiązania:
https://bibliotekanauki.pl/articles/1968872.pdf
Data publikacji:
1998-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.70.+e
Opis:
Angular differential cross-sections for the formation of He$\text{}^{0}$ in collision between fast He$\text{}^{+}$ ions are calculated using distorted wave Coulomb-Born approximation. The interaction potentials satisfy necessary Coulomb boundary conditions. In absence of any other theoretical results the present results are compared with the existing experimental data.
Źródło:
Acta Physica Polonica A; 1998, 93, 4; 601-610
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Single Ionization of He by High-Energy Proton and Antiproton. A QED Approach
Autorzy:
Bhattacharyya, S.
Pathak, K.
Powiązania:
https://bibliotekanauki.pl/articles/2014235.pdf
Data publikacji:
2000-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.80.Dp
82.30.Fi
Opis:
We have investigated single ionization of He by fast proton and antiproton using a QED approach. A field theoretical calculation gives the total cross-section of He in single ionization, from which it is seen that the projectile p$\text{}^{+}$ or p$\text{}^{-}$ gives almost the same values of cross-section. We have also compared our results with other theoretical and experimental results available in this context yet. Behaviour of the cross-section at a lower spectrum of projectile energy is discussed.
Źródło:
Acta Physica Polonica A; 2000, 98, 4; 335-344
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electron-ion Recombination at Sub-zero Temperature
Autorzy:
Bhattacharyya, S.
Roy, A.
Powiązania:
https://bibliotekanauki.pl/articles/2008325.pdf
Data publikacji:
1999-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.70.Fw
34.80.Kw
Opis:
In this paper we have considered two-step radiative recombination channel over the existing spontaneous radiative recombination channel to explain the causes of experimentally obtained enhanced recombination rate at sub-zero temperature. The existing recombination rate due to spontaneous radiative recombination is 4 times smaller than the recent experimental data. In the case of Ne$\text{}^{10+}$ we obtain good agreement between theory and experiment when contribution from two-step radiative recombination channel is added to the spontaneous radiative recombination channel. Recombination rate for Ar$\text{}^{18+}$ is calculated. The radiation spectrum given out by two-step radiative recombination and spontaneous radiative recombination in the recombination rate processes are discrete spectrum and continuous spectrum, respectively. Experimental identification of these two channels through the spectral signatures is suggested.
Źródło:
Acta Physica Polonica A; 1999, 95, 6; 911-920
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoionization of He - a Field Theoretic Approach
Autorzy:
Bhattacharyya, S.
Mitra, S.
Powiązania:
https://bibliotekanauki.pl/articles/2028891.pdf
Data publikacji:
2001-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.80.Cy
32.80.Fb
Opis:
The present paper deals with the field theoretic study of single ionization cross-sectionsσ$\text{}_{ph}$ and σ$\text{}_{C}$ of helium due to photoelectric effect and the Compton scattering, respectively, by photons of energy lying between 0-12 keV. In this energy range,σ$\text{}_{ph}$ gradually decreases with energy whileσ$\text{}_{C}$ gradually increases. There is a crossover point around 6.5 keV where σ$\text{}_{ph}$=σ$\text{}_{C}$=10$\text{}^{-24}$ cm$\text{}^{2}$. Near about this crossover point σ$\text{}_{ph}$ andσ$\text{}_{C}$ curves are like mirror images. The ratio σ$\text{}_{C}$/σ$\text{}_{ph}$ lies between 0.3 to 1.5 in the energy range under consideration. The present results are compared with existing theoretical results.
Źródło:
Acta Physica Polonica A; 2001, 100, 4; 505-516
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Three-Particle Recombination at Low Temperature: a QED Approach
Autorzy:
Bhattacharyya, S.
Roy, A.
Powiązania:
https://bibliotekanauki.pl/articles/2027431.pdf
Data publikacji:
2001-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
32.80.Fb
33.55.Ad
Opis:
A theoretical study of the three-body recombination of proton and electron in presence of a spectator electron with electronic beam at near-zero temperature is presented using field theory and invariant Lorentz gauge. Contributions from the Feynman diagrams of different orders give an insight into the physics of the phenomena. Recombination rate coefficient is obtained for low lying principal quantum number n=1 to 10. At a fixed ion beam temperature (300 K) recombination rate coefficient is found to increase in general with n, having a flat and a sharp peak at quantum states 3 and 5, respectively. In absence of any other theoretical and experimental results for low temperature formation of H-atom by three-body recombination at low lying quantum states, we have presented the theoretical results of Stevefelt and group for three-body recombination of deuteron with electron along with the present results. Three-body recombination of antihydrogen in antiproton-positron plasma is expected to yield similar result as that for three-body recombination of hydrogen formation in proton-electron plasma. The necessity for experimental investigation of low temperature three-body recombination at low quantum states is stressed.
Źródło:
Acta Physica Polonica A; 2001, 100, 1; 23-40
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Operating characteristics of transcritical CO2 heat pump for simultaneous water cooling and heating
Autorzy:
Sarkar, J.
Bhattacharyya, S.
Powiązania:
https://bibliotekanauki.pl/articles/240930.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
charakterystyki pracy
eksperyment
pompa ciepła
symulacja
CO2 heat pump
experiment
performance characteristics
simulation
Water cooling and heating
Opis:
The effects of water-side operating conditions (mass flow rates and inlet temperatures) of both evaporator and gas cooler on the experimental as well as simulated performances (cooling and heating capacities, system coefficient of performance (COP) and water outlet temperatures) of the transcritical CO2 heat pump for simultaneous water cooling and heating the are studied and revised. Study shows that both the water mass flow rate and inlet temperature have significant effect on the system performances. Test results show that the effect of evaporator water mass flow rate on the system performances and water outlet temperatures is more pronounced (COP increases by 0.6 for 1 kg/min) compared to that of gas cooler water mass flow rate (COP increases by 0.4 for 1 kg/min) and the effect of gas cooler water inlet temperature is more significant (COP decreases by 0.48 for given range) compared to that of evaporator water inlet temperature (COP increases by 0.43 for given range). Comparisons of experimental values with simulated results show the maximum deviation of 5% for cooling capacity, 10% for heating capacity and 16% for system COP.
Źródło:
Archives of Thermodynamics; 2012, 33, 4; 23-40
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influences of a "hybrid grid" on the networks voltage quality and supply reliability
Autorzy:
Bhattacharyya, S.
Myrzik, J.
Meeuwsen, J.
Powiązania:
https://bibliotekanauki.pl/articles/262592.pdf
Data publikacji:
2007
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie
Tematy:
hybrid grid
DG
power system reliability
voltage quality
interruption
NaS storage system
Opis:
The electricity is a basic need for functioning of modern society. In the deregulated electricity market, delivering quality power to the clients is a challenge for the utilities. In this paper, a "hybrid grid" is discussed that consists of centralized generations and localized distributed generations which may be comprised of small-scale conventional and sustainable sources. Energy storage option is also integrated in the hybrid-grid. Simulations are done on a test network, using "Power-Factory" software. It was found from the analysis that voltage quality and power supply availability of a hybrid-grid can be improved by proper selection of energy storage system along with protective and control devices.
Źródło:
Electrical Power Quality and Utilisation. Journal; 2007, 13, 2; 25-31
1896-4672
Pojawia się w:
Electrical Power Quality and Utilisation. Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Motor unit involvement and activities in respiratory muscles during spirometric measurements of obstructive and restrictive lung diseases in 14-20 years male
Autorzy:
Nandy, P.
Sawoo, R.
Bhattacharyya, S.
Bandyopadhyay, A.
Powiązania:
https://bibliotekanauki.pl/articles/1918930.pdf
Data publikacji:
2020-06-10
Wydawca:
Uniwersytet Medyczny w Białymstoku
Tematy:
Motor units
respiratory muscles
lung volume
surface EMG
Opis:
Introduction: Breathing involves respiratory muscle activities by recruiting motor units. The obstructive and restrictive lung diseases were categorized based on spirometric measurement. Measurement of respiratory muscle function is important in the diagnosis of respiratory disease or dysfunction. Purpose: This study focuses on the involvement of motor units in diaphragm, external intercostals and latissimus dorsi muscles during voluntary contractions in young boys having obstructive and restrictive lung diseases. Materials and methods: Fifty eight young male (14-20 years) were participated and they were grouped into three (normal, restrictive and obstructive) according to their lung condition measured by Spirometry. One way ANOVA was done to understand the significant differences between the muscles of three groups. Involvement of motor unit was shown by plotting the Line diagrams. Mean and standard deviation along with one way ANOVA were calculated in case of three respiratory muscles (External intercostals, Diaphragm, and latissimus dorsi) for three groups. Results: No significant differences were found among three groups during performing Forced vital capacity (FVC), Slow vital capacity (SVC), Maximum voluntary ventilation (MVV), and Minute ventilation (MV). Line diagram shows that during FVC, SVC, and MVV responses of different muscles are higher in three different groups except during MV. Conclusion: This study states that motor unit involvement is different in the case of three different conditions. It can be concluded that restrictive and obstructive diseases might not be interpreted on the basis of only spirometric measurements in static and dynamic lung conditions. Motor unit activation and responses of major respiratory muscles were important determinants during spirometric measurements
Źródło:
Progress in Health Sciences; 2020, 10(1); 35-42
2083-1617
Pojawia się w:
Progress in Health Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Angular Differential Cross-Sections for Electron Transfer in Collisions between Proton and He$\text{}^{+}$(1s) Ions
Autorzy:
Bhattacharyya, S.
Pathak, K.
Becker, A.
Faisal, F. H. M.
Powiązania:
https://bibliotekanauki.pl/articles/1952747.pdf
Data publikacji:
1996-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
34.70.+e
34.40.+n
Opis:
Angular differential cross-sections for the formation of H, as a result of electron capture by proton from He$\text{}^{+}$(1s) at the centre-of-mass energies from 4 to 24 keV, are calculated using distorted wave Coulomb-Born approximation. The total interaction potentials in the prior-interaction channel and in the post-interaction channel are considered. Coulomb boundary conditions are taken care of with the proper choice of the perturbation potentials in both the prior and the post channels. A prior-post discrepancy is noted. Existing theoretical results are presented along with the present results.
Źródło:
Acta Physica Polonica A; 1996, 90, 6; 1143-1153
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Assessment of viable fungi in indoor air: a case study from Tagore’s residence at Jorasanko, India
Autorzy:
Bhattacharyya, S.
Mukherjee, D.
Sarkar, P.
Ghosh, S.
Samaddar, B.
Chaudhuri, P.
Powiązania:
https://bibliotekanauki.pl/articles/11560.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
assessment
viable fungi
fungi
indoor air
indoor environment
Tagore’s residence
Jorasanko
India
Opis:
Indoor environment is significant with respect to human health especially if it is concerned when the building is v. Aim of very old. In the present study was to assess the presence of airborne fungi at an old building in Kolkata India where lots of tourists are exposed every day. Residence of famous Nobel laureate poet Rabindranath Tagore (built in the 18th century and presently used as a famous museum) in Kolkata, West Bengal was selected for this study and the indoor fungi from different room of the museum were assessed by using exposure plate technique. Humidity, temperature, wind speed and illuminance were also measured by hygrometer, thermometer anemometer and lux-meter respectively. The fungal species isolated from the air samples of different rooms were Aspergillus sp., Penicillium sp., Paecilomyces sp., Trichoderma sp, Alternaria sp Verticillium sp, Fusarium sp, Cladosporium sp, Yeast, Curvularia sp. and Helminthosporium sp. among them, Aspergillus sp. (71.4% at monsoon at library), Penicillium sp (57% at summer at library), Paecilomyces sp.(91% at monsoon at manuscript room) are mostly dominated pathogens, which may harm the workers and visitors of the museum. No significant correlation among colony forming unit of fungi with illuminance, wind speed and temperature in the tested indoor environment was noted whereas, the humidity in indoor environment played a crucial (P<0.05) role. Round the year humidity control may be required for maintaining healthy environment.
Źródło:
International Letters of Natural Sciences; 2015, 06
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Photoconductivity Study of Sputter-Deposited $Cu_2O$ Films
Autorzy:
Bhattacharyya, S.
Reppin, D.
Sanguino, P.
Ayouchi, R.
Polity, A.
Schwarz, R.
Hofmann, D.
Meyer, B.
Powiązania:
https://bibliotekanauki.pl/articles/1492344.pdf
Data publikacji:
2011-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.-w
73.50.-h
73.61.-r
Opis:
Cuprous oxide $(Cu_2O)$ thin films were deposited by radio frequency sputtering technique on fused silica substrates. The X-ray diffraction study of the $Cu_2O$ samples showed reflections from (111) and (200) planes of cubic $Cu_2O$. The samples were then annealed at 1008 K in nitrogen $(N_2)$ atmosphere. Annealed samples indicated strain relaxation. The samples were then characterized optically by measuring the transmittance using an ultraviolet-visible-near infrared photospectrometer. The band gap of the as-deposited samples were found to be ≈ 2.1 eV, whereas the annealed samples had a band gap of ≈ 2.6 eV. The transient photocurrent decay measurements of the annealed films indicated slow non-exponential power law decays in several time windows, indicating multiple trapping of the carriers in the deep defects within the band gap. The steady-state photo and dark current measurement and persistent photocurrent (PPC) was carried out on the annealed samples. In general, the photocurrent was found to be much smaller than the dark current. The steady-state and transient photocurrent measurements were utilized to determine the carrier lifetime-mobility product, 〈μτ 〉 of the samples and to determine the carrier mobility, 〈μ 〉.
Źródło:
Acta Physica Polonica A; 2011, 120, 6A; A-011-A-014
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-12 z 12

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