Informacja

Drogi użytkowniku, aplikacja do prawidłowego działania wymaga obsługi JavaScript. Proszę włącz obsługę JavaScript w Twojej przeglądarce.

English (EN)·Polski (PL)·Yкраїнський (UK)
Przejdź do strony domowej biblioteki Centralna Biblioteka Wojskowa Link otwiera się w nowym oknie Logo biblioteki Prolib Integro - strona głównaCentralna Biblioteka Wojskowa

Wyszukujesz frazę "Kumar, K.S." wg kryterium: Autor

  Lista filtrów
Wyrównaj
Wyświetlanie 1-15 z 63
Tytuł:
A Bayes algorithm for model compatibility and comparison of ARMA( p; q) models
Autorzy:
Tripathi, Praveen Kumar
Sen, Rijji
Upadhyay, S. K.
Powiązania:
https://bibliotekanauki.pl/articles/1054568.pdf
Data publikacji:
2021-06-04
Wydawca:
Główny Urząd Statystyczny
Tematy:
ARMA model
exact likelihood
Gibbs sampler
Metropolis algorithm
posterior predictive loss
model compatibility
Ljung-Box-Pierce statistic
GDP growth rate
Opis:
The paper presents a Bayes analysis of an autoregressive-moving average model and its components based on exact likelihood and weak priors for the parameters where the priors are defined so that they incorporate stationarity and invertibility restrictions naturally. A Gibbs- Metropolis hybrid scheme is used to draw posterior-based inferences for the models under consideration. The compatibility of the models with the data is examined using the Ljung- Box-Pierce chi-square-based statistic. The paper also compares different compatible models through the posterior predictive loss criterion in order to recommend the most appropriate one. For a numerical illustration of the above, data on the Indian gross domestic product growth rate at constant prices are considered. Differencing the data once prior to conducting the analysis ensured their stationarity. Retrospective short-term predictions of the data are provided based on the final recommended model. The considered methodology is expected to offer an easy and precise method for economic data analysis.
Źródło:
Statistics in Transition new series; 2021, 22, 2; 95-123
1234-7655
Pojawia się w:
Statistics in Transition new series
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A report on occurrence of Neofusicoccum sp. in Carallia brachiata (Lour.) Merr. trees from Karnataka, India
Autorzy:
Muthu Kumar, A.
Pandey, A.K.
Mishra, G.
Rao, S.
Powiązania:
https://bibliotekanauki.pl/articles/11572.pdf
Data publikacji:
2015
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Opis:
Carallia brachiata (Lour.) Merr. is one of the soft woody species occurring all along the Western Ghats region of Kundapura, Karnataka, India. The species is considered to be a potent medicinal plant exclusively used against itch and septic poisoning. A study was under gone based on the report of forest department (Karnataka) on mortality of Carallia brachiata. Observation of symptoms on the infected trees and experimental analysis of the samples under laboratory conditions revealed the incidence of Neofusicoccum sp., a first report on Carallia brachiata. This particular Neofusicoccum sp. belongs to Botryospaeriaceae family, and is considered to be an important fungal pathogen associated with tree decline in forest and plantation worldwide.
Źródło:
International Letters of Natural Sciences; 2015, 04
2300-9675
Pojawia się w:
International Letters of Natural Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Scheme for Template Security at Feature Fusion Level in Multimodal Biometric System
Autorzy:
Selwal, A.
Gupta, S. K.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/102518.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
feature template
biometric data
feature vectors
multimodal biometrics
fuzzy sets
database
feature fusion
Opis:
Biometrics is the science of human recognition by means of their biological, chemical or behavioural traits. These systems are used in many real life applications simply from biometric based attendance system to providing security at a very sophisticated level. A biometric system deals with raw data captured using a sensor and feature template extracted from raw image. One of the challenges being faced by designers of these systems is to secure template data extracted from the biometric modalities of the user and protect the raw images. In order to minimize spoof attacks on biometric systems by unauthorised users one of the solutions is to use multi-biometric systems. Multi-modal biometric system works by using fusion technique to merge feature templates generated from different modalities of the human. In this work, a novel scheme is proposed to secure template during feature fusion level. The scheme is based on union operation of fuzzy relations of templates of modalities during fusion process of multimodal biometric systems. This approach serves dual purpose of feature fusion as well as transformation of templates into a single secured non invertible template. The proposed technique is irreversible, diverse and experimentally tested on a bimodal biometric system comprising of fingerprint and hand geometry. The given scheme results into significant improvement in the performance of the system with lower equal error rate and improvement in genuine acceptance rate.
Źródło:
Advances in Science and Technology. Research Journal; 2016, 10, 31; 23-30
2299-8624
Pojawia się w:
Advances in Science and Technology. Research Journal
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Achieving cost efficiency through increased inventory leanness: Evidence from manufacturing industry
Autorzy:
Mor, Rahul S.
Kumar, Dinesh
Yadav, Sarika
Jaiswal, Swatantra K.
Powiązania:
https://bibliotekanauki.pl/articles/1839570.pdf
Data publikacji:
2021
Wydawca:
Stowarzyszenie Menedżerów Jakości i Produkcji
Tematy:
zarządzanie zapasami
ABC
analiza VED
przemysł wytwórczy
inventory management
VED analysis
manufacturing industry
lean production
Opis:
Inventory management’s fundamental problem starts with maintaining equilibrium among the operating efficiency, cost of investment, and other allied costs with extensive inventories to keep the actual conflicts at the minimum while optimizing the inventory holding levels. But, inventory management practices have not been well exploited in various manufacturing industries yet. In this study, inventory management tools, i.e., ABC and VED analysis, have been applied in the manufacturing industry, considering 146 items as raw material for an assembly. A total of 15 items under ‘AV’ class have been identified that consume 82.05 % of the total cost, and these items need strict control and frequent ordering. Sigma level of suppliers is also calculated, which comes out to be 2.36, and it must be improved to reduce the overall inventory cost.
Źródło:
Production Engineering Archives; 2021, 27, 1; 42-49
2353-5156
2353-7779
Pojawia się w:
Production Engineering Archives
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An ailuravine rodent from the lower Eocene Cambay Formation at Vastan, western India, and its palaeobiogeographic implications
Autorzy:
Rana, R S
Kumar, K.
Escarguel, G.
Sahni, A.
Rose, K.D.
Smith, T.
Singh, H.
Singh, L.
Powiązania:
https://bibliotekanauki.pl/articles/23190.pdf
Data publikacji:
2008
Wydawca:
Polska Akademia Nauk. Instytut Paleobiologii PAN
Tematy:
Ischyromyidae
Cambay Formation
paleontology
Euromys inexpectatus
Euromys cardosoi
Rodentia
Eocene
India
Ailuravinae
Meldimys musak
Mammalia
ailuravine rodent
new species
Ailuravus michauxi
rodent
paleobiogeography
Western India
Opis:
A new ailuravine rodent, Meldimys musak sp. nov. (Mammalia: Rodentia, Ischyromyidae), is recorded from the lower Eocene lignites of western India. It is the oldest record of Rodentia from India. M. musak is more derived than the earliest Eocene ailuravine Euromys cardosoi from Portugal and more generalized than late early Eocene E. inexpectatus and Ailuravus michauxi from France. Its dental morphology closely corresponds to the middle early Eocene species M. louisi, which lived about 52 Ma in Western Europe. Meldimys was previously known only from Europe, and ailuravines were previously reported only from Europe and North America. Its occurrence in India allows the first direct correlation between the early Eocene land mammal horizons of Europe and India, and raises the possibility of a terrestrial faunal exchange between India and Eurasia close to the Palaeocene–Eocene transition.
Źródło:
Acta Palaeontologica Polonica; 2008, 53, 1
0567-7920
Pojawia się w:
Acta Palaeontologica Polonica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Applicability of artificial intelligence in smart healthcare systems for automatic detection of Parkinson’s Disease
Autorzy:
Pallathadka, Harikumar
Padminivalli V., S.J.R.K.
Vasavi, M.
Nancy, P.
Naved, Mohd
Kumar, Harish
Ray, Samrat
Powiązania:
https://bibliotekanauki.pl/articles/38709253.pdf
Data publikacji:
2024
Wydawca:
Instytut Podstawowych Problemów Techniki PAN
Tematy:
Parkinson’s disease
detection
machine learning
relief algorithm
LDA algorithm
SVM-RBF
accuracy
sensitivity
specificity
choroba Parkinsona
wykrywanie
nauczanie maszynowe
algorytm ulgi
Algorytm LDA
dokładność
wrażliwość
specyficzność
Opis:
Parkinson’s disease is associated with memory loss, anxiety, and depression in the brain. Problems such as poor balance and difficulty during walking can be observed in addition to symptoms of impaired posture and rigidity. The field dedicated to making computers capable of learning autonomously, without having to be explicitly programmed, is known as machine learning. An approach to the diagnosis of Parkinson’s disease, which is based on artificial intelligence, is discussed in this article. The input for this system is provided through photographic examples of Parkinson’s disease patient handwriting. Received photos are preprocessed using the relief feature option to begin the process. This is helpful in the process of selecting characteristics for the identification of Parkinson’s disease. After that, the linear discriminant analysis (LDA) algorithm is employed to reduce the dimensions, bringing down the total number of dimensions that are present in the input data. The photos are then classified via radial basis function-support vector machine (SVM-RBF), k-nearest neighbors (KNN), and naive Bayes algorithms, respectively.
Źródło:
Computer Assisted Methods in Engineering and Science; 2024, 31, 2; 175-185
2299-3649
Pojawia się w:
Computer Assisted Methods in Engineering and Science
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ballistic studies of lightweight materials - a review
Autorzy:
Balaji, S.
Kumar, S. Dharani
Moorthy, K. Chandra
Javeed, M. Mohamed
Dharanidharan, D.
Powiązania:
https://bibliotekanauki.pl/articles/95205.pdf
Data publikacji:
2020
Wydawca:
Politechnika Koszalińska. Wydawnictwo Uczelniane
Tematy:
lightweight materials
ballistics
heat treatment
numerical studies
materiały lekkie
balistyka
obróbka cieplna
badania modelowe
Opis:
A recent development in the material studies provides beneficial application of lightweight alloys such as aluminium, magnesium as well as composites and metal matrices. The alloys are experimentally improved by increasing hardness in the ballistics testing using projectiles,makes them viable for the areas such as aerospace, military, defence, automobiles and so on. So the study is made on different approaches. First, by comparing different types of non-ferrous alloys and projectiles regarding sizes, structures. Second, the materials with heat treatment are also studied for investigating the hardness property by overcoming successful penetration on non-ferrous alloys. Third, material to be improvised by use of numerical studies such as 3D models, empirical models and software such as ANSYS, ABAQUS and AUTODYN, etc. Finally, the aim of this paper is to review the recent progress ballistic studies of lightweight materials and to provide a best choice of material for further on-going research.
Źródło:
Journal of Mechanical and Energy Engineering; 2020, 4, 1; 7-14
2544-0780
2544-1671
Pojawia się w:
Journal of Mechanical and Energy Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Change in entropy of the spinning black holes
Autorzy:
Mahto, D.
Singh, A. S.
Vineeta, K.
Kumar, A.
Powiązania:
https://bibliotekanauki.pl/articles/411895.pdf
Data publikacji:
2014
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Event-horizon
AGN
Entropy & Energy
Opis:
Aims: To derive an expression for change in entropy of spinning black holes on the basis of the model for the energy of spinning black holes E BHs= KBHs R's ( Mahto et al. 2011a) & the model for entropy change δS bh = [wzór]δE ( Mahto et al. 2011b) and then calculate their values for different test spinning black holes. Study Design: Data for the mass of black holes have collected from the research paper entitled :Super massive Black Holes in Galactic Nuclei: Past Present & Future Research(2005), Space Science Reviews by L. Ferrarese & H. Ford and Black holes in Astrophysics(2005), New Journal Physics by R. Narayan. The data for black hole constant for spinning black holes (K BHs = 1.214x1044) is taken from the paper entitled: Study of Schwarzschild radius with reference to the spinning black holes. Bulletin of Pure and Applied Sciences (2011a). Place and Duration of Study: Department of Physics, Marwari College Bhagalpur and University Department of Physics, T.M.B.U. Bhagalpur, between December 2013 and March 2014. Methodology: A theoretical based work using Laptop to calculate the calculation for change in entropy of different test spinning black holes at Marwari College Bhagalpur and the residential research chamber of the first author. Results: The calculation shows that the change in entropy of spinning black holes of the rest masses for stellar – mass black holes (M ~ 5 – 20 Mʘ) in X-ray binaries is 2.483x10 63 to 39.731x10 63 J/K and for the super massive Black holes (M ~ 10 6 – 109.5 Mʘ) in active galactic nuclei is 9.932x10 73 to 28.432x10 80 J/K. The nature of the graph for XRBs is the same to the Hawking entropy with the event horizon and straight line for AGN which confirms the validity of equations EBHs=KBHs R’s and δS bh = [wzór]δE .Conclusion: The change in energy and entropy of black holes are mainly dependent on the mass and independent of their event horizons.
Źródło:
International Letters of Chemistry, Physics and Astronomy; 2014, 13, 2; 95-103
2299-3843
Pojawia się w:
International Letters of Chemistry, Physics and Astronomy
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Chatter detection using principal component analysis in cold rolling mill
Autorzy:
Usmani, N. I.
Kumar, S.
Velisatti, S.
Tiwari, P. K.
Mishra, S. K.
Patnaik, U. S.
Powiązania:
https://bibliotekanauki.pl/articles/329460.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
chatter
principal component analysis
PCA
cold rolling
vibration
drgania samowzbudne
analiza składowych głównych
walcowanie na zimno
drgania
Opis:
Most cold rolling mills are prone to chatter problem. Chatter marks are often observed on the strip surface in cold rolling mill leading to downgrade and rejection of rolled material. Chatter impact product quality as well as productivity of mill. In absence of online chatter detection no corrective action can be taken immediately and whole campaign gets affected. Most conventional approach for online chatter detection is by using vibration measurement of mill stands in time & frequency domain. Present work proposes two approaches to detect chatter in cold rolling mill using a statistical technique called Principal Component Analysis (PCA). In this paper two methods are used for chatter detection. First method applies PCA on Fast Fourier Transform (FFT) to differentiate between chatter and non-chatter condition. Second method applies PCA on statistical parameters calculated from raw vibration data to detect chatter.
Źródło:
Diagnostyka; 2018, 19, 1; 73-81
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative evaluation of inversion approaches of the radiative transfer model for estimation of crop biophysical parameters
Autorzy:
Mridha, N.
Sahoo, R.N.
Sehgal, V.K.
Krishna, G.
Pargal, S.
Pradhan, S.
Gupta, V.K.
Nagesh Kumar, D.
Powiązania:
https://bibliotekanauki.pl/articles/25984.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Instytut Agrofizyki PAN
Opis:
The inversion of canopy reflectance models is widely used for the retrieval of vegetation properties from remote sensing. This study evaluates the retrieval of soybean biophysical variables of leaf area index, leaf chlorophyll content, canopy chlorophyll content, and equivalent leaf water thickness from proximal reflectance data integrated broad bands corresponding to moderate resolution imaging spectroradiometer, thematic mapper, and linear imaging self scanning sensors through inversion of the canopy radiative transfer model, PROSAIL. Three different inversion approaches namely the look-up table, genetic algorithm, and artificial neural network were used and performances were evaluated. Application of the genetic algorithm for crop parameter retrieval is a new attempt among the variety of optimization problems in remote sensing which have been successfully demonstrated in the present study. Its performance was as good as that of the look-up table approach and the artificial neural network was a poor performer. The general order of estimation accuracy for para-meters irrespective of inversion approaches was leaf area index > canopy chlorophyll content > leaf chlorophyll content > equivalentleaf water thickness. Performance of inversion was comparable for broadband reflectances of all three sensors in the optical region with insignificant differences in estimation accuracy among them.
Źródło:
International Agrophysics; 2015, 29, 2
0236-8722
Pojawia się w:
International Agrophysics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Comparative study of GA & DE algorithm for the economic operation of a power system using FACTS devices
Autorzy:
Bhattacharyya, B.
Gupta, V. K.
Kumar, S.
Powiązania:
https://bibliotekanauki.pl/articles/141459.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
FACTS devices
line power flow
FACTS devices & its optimal locations
genetic algorithm
differential evolution technique
Opis:
The problem of improving the voltage profile and reducing power loss in electrical networks must be solved in an optimal manner. This paper deals with comparative study of Genetic Algorithm (GA) and Differential Evolution (DE) based algorithm for the optimal allocation of multiple FACTS (Flexible AC Transmission System) devices in an interconnected power system for the economic operation as well as to enhance loadability of lines. Proper placement of FACTS devices like Static VAr Compensator (SVC), Thyristor Controlled Switched Capacitor (TCSC) and controlling reactive generations of the generators and transformer tap settings simultaneously improves the system performance greatly using the proposed approach. These GA & DE based methods are applied on standard IEEE 30 bus system. The system is reactively loaded starting from base to 200% of base load. FACTS devices are installed in the different locations of the power system and system performance is observed with and without FACTS devices. First, the locations, where the FACTS devices to be placed is determined by calculating active and reactive power flows in the lines. GA and DE based algorithm is then applied to find the amount of magnitudes of the FACTS devices. Finally the comparison between these two techniques for the placement of FACTS devices are presented.
Źródło:
Archives of Electrical Engineering; 2013, 62, 4; 541-552
1427-4221
2300-2506
Pojawia się w:
Archives of Electrical Engineering
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Corrosion Inhibition of Mild Steel in Nitric Acid Media by some Schiff Bases Derived from Anisalidine
Autorzy:
Saxena, N.
Kumar, S.
Sharma, M. K.
Mathur, S. P.
Powiązania:
https://bibliotekanauki.pl/articles/779278.pdf
Data publikacji:
2013
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
Schiff base
degradation
inhibitor and mild steel
Opis:
Corrosion inhibition performance of mild steel in nitric acid solution containing different concentration of anisalidine derivative Schiff bases viz. N- (4-nitro phenyl) p-anisalidine (SB1), N- (4-chloro phenyl) p-anisalidine (SB2), N- (4-phenyl) p-anisalidine (SB3), N- (4-methoxy phenyl) p-anisalidine (SB4), N- (4-hydroxy phenyl) p-anisalidine (SB5) has been investigated using mass loss, thermometric and potentiostate polarization technique. Inhibition efficiencies of Schiff bases have been evaluated at different acid strength. The inhibition efficiency was found larger than their parent amines. Inhibition efficiencies of synthesized Schiff bases increase with inhibitor concentration. Inhibition efficiency increases up to 98.32% with ansalidine derivative Schiff base.
Źródło:
Polish Journal of Chemical Technology; 2013, 15, 1; 61-67
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and analysis of a novel concept-based unmanned aerial vehicle with ground traversing capability
Autorzy:
Kumar, Ramanuj
Gour, Surjeet S.
Pandey, Anish
Kumar, Shrestha
Mohan, Abhijeet
Shashwat, Pratik
Sahoo, Ashok K.
Powiązania:
https://bibliotekanauki.pl/articles/2105984.pdf
Data publikacji:
2022
Wydawca:
Politechnika Białostocka. Oficyna Wydawnicza Politechniki Białostockiej
Tematy:
unmanned aerial vehicle
unmanned ground vehicle
rough terrain
quadcopter
caterpillar wheel
kinematic analysis
Opis:
Unmanned aerial vehicle (UAV) is a typical aircraft that is operated remotely by a human operator or autonomously by an on-board microcontroller. The UAV typically carries offensive ordnance, target designators, sensors or electronic transmitters designed for one or more applications. Such application can be in the field of defence surveillance, border patrol, search, bomb disposals, logistics and so forth. These UAVs are also being used in some other areas, such as medical purposes including for medicine delivery, rescue operations, agricultural applications and so on. However, these UAVs can only fly in the sky, and they cannot travel on the ground for other applications. Therefore, in this paper, we design and present the novel concept-based UAV, which can also travel on the ground and rough terrain as an unmanned ground vehicle (UGV). This means that according to our requirement, we can use this as a quadcopter and caterpillar wheel–based UGV using a single remote control unit. Further, the current study also briefly discusses the two-dimensional (2D) and three-dimensional (3D) SolidWorks models of the novel concept-based combined vehicle (UAV + UGV), together with a physical model of a combined vehicle (UAV + UGV) and its various components. Moreover, the kinematic analysis of a combined vehicle (UAV + UGV) has been studied, and the motion controlling kinematic equations have been derived. Then, the real-time aerial and ground motions and orientations and control-based experimental results of a combined vehicle (UAV + UGV) are presented to demonstrate the robustness and effectiveness of the proposed vehicle.
Źródło:
Acta Mechanica et Automatica; 2022, 16, 3; 169--179
1898-4088
2300-5319
Pojawia się w:
Acta Mechanica et Automatica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Design and Evaluation of the Thermal Properties of Di-, Tri- and Tetra-Azido-Esters
Autorzy:
Kumar, S.
Kumar, A.
Yamajala, K. D. B.
Gaur, P.
Kumar, D.
Banerjee, S.
Powiązania:
https://bibliotekanauki.pl/articles/358266.pdf
Data publikacji:
2017
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Przemysłu Organicznego
Tematy:
azido-esters
energetic plasticizers
DFT
contact angle
Opis:
A group of polycyclic and aliphatic azido-esters (as energetic plasticizers) have been synthesized by simple synthetic routes and their molecular structures were confirmed by spectroscopic techniques. In addition, their thermal and rheological properties have been determined utilizing DSC, TGA, viscosity, and contact angle. Computational studies of these plasticizers have been performed by means of DFT (B3LYP/6-31G*) to estimate possible stable structures, energies, heat of formation, bond dissociation energies, IR and NMR spectra etc. Their compatibility with glycidyl azide polymer (GAP) binder was studied to explore their applicability in propellants. All of these molecules are novel and have been synthesized with the possibility of scale up.
Źródło:
Central European Journal of Energetic Materials; 2017, 14, 4; 844-860
1733-7178
Pojawia się w:
Central European Journal of Energetic Materials
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
DFT and TD-DFT Calculations of Some Metal Free Phthalonitrile Derivatives for Enhancement of the Dye Sensitized Solar Cells
Autorzy:
Anbarasan, P.
Senthil Kumar, P.
Vasudevan, K.
Moorthy Babu, S.
Aroulmoji, V.
Powiązania:
https://bibliotekanauki.pl/articles/1505357.pdf
Data publikacji:
2011-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
78.66.Qn
31.10.+z
71.15.Mb
32.30.-r
Opis:
The geometries, electronic structures, polarizabilities, and hyperpolarizabilities of organic dye sensitizers 3,4-pyridinedicarbonitrile, 3-aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile were studied based on density functional theory using the hybrid functional B3LYP. Ultraviolet-visible spectra were investigated by time dependent density functional theory. The features of electronic absorption spectra in the visible and near-UV regions were assigned based on time dependent density functional theory calculations. The absorption bands are assigned to π → π* transitions. Calculated results suggest that the three lowest energy excited states of 3,4-pyridinedicarbonitrile, 3-aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile are due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor $TiO_2$ electrode and dye sensitizers 3,4-pyridinedicarbonitrile, 3-aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile is due to an electron injection process from excited dyes to the semiconductor's conduction band. The role of amide and methyl groups in phthalonitrile in geometries, electronic structures, and spectral properties were analyzed in a comparative study of 3,4-pyridinedicarbonitrile, 3-aminophthalonitrile, 4-aminophthalonitrile and 4-methylphthalonitrile for the improvement of dye sensitized solar cells.
Źródło:
Acta Physica Polonica A; 2011, 119, 3; 395-404
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 63

Ta witryna wykorzystuje pliki cookies do przechowywania informacji na Twoim komputerze. Pliki cookies stosujemy w celu świadczenia usług na najwyższym poziomie, w tym w sposób dostosowany do indywidualnych potrzeb. Korzystanie z witryny bez zmiany ustawień dotyczących cookies oznacza, że będą one zamieszczane w Twoim komputerze. W każdym momencie możesz dokonać zmiany ustawień dotyczących cookies