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2006

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Articles 4801 - 4830 of 5872

Full-Text Articles in Physical Sciences and Mathematics

The Solar Flare Of The 14th Of July 2000 (L3+C Detector Results), Pablo Achard, Gyöngyi Baksay, László A. Baksay, K Dehmelt, Marcus Hohlmann, D Rembeczki, Z Szillasi, I Vodopianov, The L3 Collaboration Jan 2006

The Solar Flare Of The 14th Of July 2000 (L3+C Detector Results), Pablo Achard, Gyöngyi Baksay, László A. Baksay, K Dehmelt, Marcus Hohlmann, D Rembeczki, Z Szillasi, I Vodopianov, The L3 Collaboration

Aerospace, Physics, and Space Science Faculty Publications

Aims.Several experiments have reported observations on possible correlations between the flux of high energy muons and intense solar flares. If confirmed, these observations would have significant implications for acceleration processes in the heliosphere able to accelerate protons and other ions to energies of at least tens of GeV. Methods.The solar flare of the 14 of July 2000 offered a unique opportunity for the L3+C experiment to search for a correlated enhancement in the flux of muons using the L3 precision muon spectrometer. Its capabilities for observing a directional excess in the flux of muons above 15 GeV (corresponding to primary …


A Multisite Photometric Campaign On The Pre-Main-Sequence Δ Scuti Pulsator Ip Persei, Vincenzo Ripepi, T D. Oswalt Jan 2006

A Multisite Photometric Campaign On The Pre-Main-Sequence Δ Scuti Pulsator Ip Persei, Vincenzo Ripepi, T D. Oswalt

Aerospace, Physics, and Space Science Faculty Publications

We present the results of a photometric multisite campaign on the δ Scuti Pre-Main-Sequence star IP Per. Nine telescopes have been involved in the observations, with a total of about 190 h of observations over 38 nights. Present data confirms the multiperiodic nature of this star and leads to the identification of at least nine pulsational frequencies. Comparison with the predictions of linear non-adiabatic radial pulsation models allowed us to identify only five of the nine observed frequencies, and to constrain the position of IP Per in the HR diagram. The latter is in good agreement with the empirical determination …


Whole Earth Telescope Observations Of The Zz Ceti Star Hl Tau 76, Noël Dolez, Matt A. Wood, Thomas J. Ahrens, Nicole Silvestri Jan 2006

Whole Earth Telescope Observations Of The Zz Ceti Star Hl Tau 76, Noël Dolez, Matt A. Wood, Thomas J. Ahrens, Nicole Silvestri

Aerospace, Physics, and Space Science Faculty Publications

This paper analyses the Whole Earth Telescope observations of HL Tau 76, the first discovered pulsating DA white dwarf. The star was observed during two Whole Earth Telescope campaigns. It was a second priority target during the XCOV13 campaign in 1996 and the first priority one during the XCOV18 campaign in 1999. The 1999 campaign reached 66.5% duty cycle. With a total duration of 18 days, the frequency resolution achieved is 0.68 μHz. With such a frequency resolution, we were able to find as many as 78 significant frequencies in the power spectrum, of which 34 are independent frequencies after …


Runaway Breakdown In The Jovian Atmospheres, Joseph R. Dwyer, Lee M. Coleman, Ramon E. Lopez, Ziad H. Saleh, D. Concha, Michael G. Brown, Hamid K. Rassoul Jan 2006

Runaway Breakdown In The Jovian Atmospheres, Joseph R. Dwyer, Lee M. Coleman, Ramon E. Lopez, Ziad H. Saleh, D. Concha, Michael G. Brown, Hamid K. Rassoul

Aerospace, Physics, and Space Science Faculty Publications

Using detailed Monte Carlo calculations, the properties of runaway breakdown in the atmospheres of the four gas giant planets in our solar system are investigated, and the runaway avalanche lengths and average runaway electron kinetic energies are presented as a function of atmospheric electric field strengths. The runaway breakdown threshold field for the Jovian atmospheres is found to be 10 times smaller than the conventional breakdown field when hydrometeors are present, compared to 3 times smaller for Earth's atmosphere, indicating that runaway breakdown processes may be much more efficient in the gas giants than on Earth. In the Earth's atmosphere, …


Origin Of Heavy Ions In Upstream Events Near The Earth's Bow Shock, Mihir I. Desai, Glenn M. Mason, Joseph E. Mazur, Joseph R. Dwyer Jan 2006

Origin Of Heavy Ions In Upstream Events Near The Earth's Bow Shock, Mihir I. Desai, Glenn M. Mason, Joseph E. Mazur, Joseph R. Dwyer

Aerospace, Physics, and Space Science Faculty Publications

We have surveyed the ∼20-160 keV/nucleon heavy ion composition of 2102 upstream events observed by the Wind/STEP instrument near the Earth's bow shock over a complete solar cycle from day 325, 1994 through day 90, 2006. Our main results are: (1) During solar minimum conditions, both the C/O and Fe/O ratios are similar to the corresponding values measured in the solar wind and/or CIRs. (2) During solar maximum conditions, the C/O ratio is similar to that measured in SEP and CME-driven IP shock events, while the Fe/O ratio lies between the values measured in IP shock and SEP events. We …


Test 1881: Mccormick Xtx 200/Mtx 185 Diesel, Nebraska Tractor Test Lab Jan 2006

Test 1881: Mccormick Xtx 200/Mtx 185 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Test 1883: Agco Lt75a Diesel, Nebraska Tractor Test Lab Jan 2006

Test 1883: Agco Lt75a Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Test 1882: Mccormick Xtx 215 Diesel, Nebraska Tractor Test Lab Jan 2006

Test 1882: Mccormick Xtx 215 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Test 1880: Mccormick Xtx 185/Mccormick Mtx 165 Diesel, Nebraska Tractor Test Lab Jan 2006

Test 1880: Mccormick Xtx 185/Mccormick Mtx 165 Diesel, Nebraska Tractor Test Lab

Nebraska Tractor Tests

No abstract provided.


Unmatter Entities Inside Nuclei, Predicted By The Brightsen Nucleon Cluster Model, Florentin Smarandache, Dmitri Rabounski Jan 2006

Unmatter Entities Inside Nuclei, Predicted By The Brightsen Nucleon Cluster Model, Florentin Smarandache, Dmitri Rabounski

Branch Mathematics and Statistics Faculty and Staff Publications

Applying the R. A. Brightsen Nucleon Cluster Model of the atomic nucleus we discuss how unmatter entities (the conjugations of matter and antimatter) may be formed as clusters inside a nucleus. The model supports a hypothesis that antimatter nucleon clusters are present as a parton (sensu Feynman) superposition within the spatial confinement of the proton (1H1), the neutron, and the deuteron (1H2). If model predictions can be confirmed both mathematically and experimentally, a new physics is suggested. A proposed experiment is connected to othopositronium annihilation anomalies, which, being related to one of known unmatter entity, orthopositronium (built on electron and …


Test 1870: John Deere 5103 Diesel 9-Speed, Nebraska Tractor Test Lab Jan 2006

Test 1870: John Deere 5103 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …


Test 1871: John Deere 5203 Diesel 9-Speed, Nebraska Tractor Test Lab Jan 2006

Test 1871: John Deere 5203 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …


Test 1872: John Deere 5303 Diesel 9-Speed, Nebraska Tractor Test Lab Jan 2006

Test 1872: John Deere 5303 Diesel 9-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …


Test 1888: John Deere 8330t Diesel 16-Speed, Nebraska Tractor Test Lab Jan 2006

Test 1888: John Deere 8330t Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …


Nebraska Summary 559: Massey Ferguson 5470 Dyna 4 Diesel 16-Speed, Nebraska Tractor Test Lab Jan 2006

Nebraska Summary 559: Massey Ferguson 5470 Dyna 4 Diesel 16-Speed, Nebraska Tractor Test Lab

Nebraska Tractor Tests

ABOUT THE TEST REPORT AND USE OF THE DATA

The test data contained in this report are a tabulation of the results of a series of tests. Due to the restricted format of these pages, only a limited amount of data and not all of the tractor specifications are included. The full OECD report contains usually about 30 pages of data and specifications. The test data were obtained for each tractor under similar conditions and therefore, provide a means of comparison of performance based on a limited set of reported data.

EXPLANATION OF THE TEST PROCEDURES

Purpose

The purpose of …


Empirical Model For The Electron-Impact K-Shell-Ionization Cross Sections, A K. F Haque, M A. Uddin, A K. Basak, K R. Karim, B C. Saha Jan 2006

Empirical Model For The Electron-Impact K-Shell-Ionization Cross Sections, A K. F Haque, M A. Uddin, A K. Basak, K R. Karim, B C. Saha

Faculty publications – Physics

The total cross sections of electron-impact single-K-shell ionization of 14 atomic targets ranging from H to U (1 <= Z <= 92) are calculated using a modified version of the BELI formula [Bell , J. Phys. Chem. Ref. Data 12, 891 (1983)] by incorporating both ionic and relativistic corrections in it. The proposed modified Bell model with a single set of parameters is found to provide an excellent description of the experimental data in the reduced energy range 1 <= E/I-K <= 10(6) (E and I-K are, respectively, the incident energy and ionization potential) with a performance level at least as good as any of the existing methods and models.


3-Methyl-5-Nitrouracil, Maciej Kubicki, Pawel Wagner Jan 2006

3-Methyl-5-Nitrouracil, Maciej Kubicki, Pawel Wagner

Australian Institute for Innovative Materials - Papers

The mol­ecules of the title compound, C5H5N3O4, are approximately planar. The nitro group makes a dihedral angle of 1.3 (4)° with the plane of the six-membered ring. This coplanar disposition is a reason for the changes in valence angles in the vicinity of the nitro group. Mol­ecules are connected into dimers by means of N—H⋯O hydrogen bonds, and these dimers make larger structures with the help of relatively short C—H⋯O hydrogen bonds.


The Effect Of Oxidation On The Structure Of Styryl-Substituted Sexithiophenes: A Resonance Raman Spectroscopy And Density Functional Theory Study, Tracy Clarke, Keith Gordon, David L. Officer, Daina K. Grant Jan 2006

The Effect Of Oxidation On The Structure Of Styryl-Substituted Sexithiophenes: A Resonance Raman Spectroscopy And Density Functional Theory Study, Tracy Clarke, Keith Gordon, David L. Officer, Daina K. Grant

Australian Institute for Innovative Materials - Papers

The structures and vibrational properties of a series of styryl-substituted sexithiophenes and their charged species have been examined using resonance Raman spectroscopy in conjunction with density functional theory calculations. The calculated geometries of the radical cations and dications indicate that the quinoidal charged defects are more strongly localized in the center of the thiophene backbone than is observed in other sexithiophenes. This defect confinement, induced by the positions of the styryl substituents, is particularly evident in the dication species. However, the defect confinement weakens when alkoxy groups are added onto the phenyl rings by causing the extension of the charged …


Solid State Ph Sensor Based On Light Emitting Diodes (Led) As Detector Platform, King Tong Lau, Roderick Shepherd, Danny Diamond, Dermot Diamond Jan 2006

Solid State Ph Sensor Based On Light Emitting Diodes (Led) As Detector Platform, King Tong Lau, Roderick Shepherd, Danny Diamond, Dermot Diamond

Australian Institute for Innovative Materials - Papers

A low-power, high sensitivity, very low-cost light emitting diode (LED)-based device developed for low-cost sensor networks was modified with bromocresol green membrane to work as a solid-state pH sensor. In this approach, a reverse-biased LED functioning as a photodiode is coupled with a second LED configured in conventional emission mode. A simple timer circuit measures how long (in microsecond) it takes for the photocurrent generated on the detector LED to discharge its capacitance from logic 1 (+5 V) to logic 0 (+1.7 V). The entire instrument provides an inherently digital output of light intensity measurements for a few cents. A …


Growth Of Width-Controlled Nanowires Mno2 From Mesoporous Carbon And Investigation Of Their Properties, Shenmin Zhu, Xiaolin Wang, Wei Huang, Deyue Yan, Honghua Wang, Di Zhang Jan 2006

Growth Of Width-Controlled Nanowires Mno2 From Mesoporous Carbon And Investigation Of Their Properties, Shenmin Zhu, Xiaolin Wang, Wei Huang, Deyue Yan, Honghua Wang, Di Zhang

Australian Institute for Innovative Materials - Papers

One-dimensional α-MnO2 nanowires with a controlled width of 10–20 nm have been developed by means of ultrasonic waves from mesoporous carbon using KMnO4 as the precursor. The formation mechanism has been proposed based on the results. A peak around 100 K was detected in the temperature-dependence of magnetization curve, indicating the ferromagnetic state in nanocomposite mesoporous carbon-MnO2, which is in agreement with the transition temperature found from the magnetization versus applied magnetic field curve. The magnetization versus temperature curve of the obtained MnO2 nanowires showed a magnetic transition at about 50 K, illustrating that a …


Spin Singlet Pairing In The Superconducting State Of Naxco02 1.3h2o: Evidence From A 59co Knight Shift In A Single Crystal, Guo-Qing Zheng, Kazuaki Matano, Dapeng Chen, C T. Lin Jan 2006

Spin Singlet Pairing In The Superconducting State Of Naxco02 1.3h2o: Evidence From A 59co Knight Shift In A Single Crystal, Guo-Qing Zheng, Kazuaki Matano, Dapeng Chen, C T. Lin

Australian Institute for Innovative Materials - Papers

We report a 59Co Knight-shift measurement in a single crystal of the cobalt oxide superconductor NaxCoO2∙1.3H2O (Tc=4.25 K). We find that the shift due to the spin susceptibility, Ks, is substantially large and anisotropic, with the spin shift along the a-axis Kas being two times that along the c-axis Kcs. The shift decreases with decreasing temperature (T) down to T≈100 K, then becomes a constant until superconductivity sets in. Both Kas and Kcs decrease below Tc. Our results indicate unambiguously that the electron pairing in the superconducting state is in the spin singlet form.


Previous Heat Treatment Inducing Different Plasma Nitriding Behaviors In Martensitic Stainless Steels, C A. Figueroa, F Alvarez, D Rg Mitchell, G A. Collins, K T. Short Jan 2006

Previous Heat Treatment Inducing Different Plasma Nitriding Behaviors In Martensitic Stainless Steels, C A. Figueroa, F Alvarez, D Rg Mitchell, G A. Collins, K T. Short

Australian Institute for Innovative Materials - Papers

In this work we report a study of the induced changes in structure and corrosion behavior of martensitic stainless steels nitrided by plasma immersion ion implantation (PI3) at different previous heat treatments. The samples were characterized by x-ray diffraction and glancing angle x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and potentiodynamic measurements. Depending on the proportion of retained austenite in the unimplanted material, different phase transformations are obtained at lower and intermediate temperatures of nitrogen implantation. At higher temperatures, the great mobility of the chromium yields CrN segregations like spots in random distribution, and the a' -martensite is …


Decompositions Of Continuity, Talal Al-Hawary, Ahmad Al-Omari Jan 2006

Decompositions Of Continuity, Talal Al-Hawary, Ahmad Al-Omari

Turkish Journal of Mathematics

In 2004, Al-Hawary and Al-Omari introduced and explored the class of \omega^o-open sets which is strictly stronger than the class of \omega-open sets and weaker than that of open sets. In this paper, we introduce what we call \omega^o-continuity and \omega_X^o-continuity and we give several characterizations and two decompositions of \omega ^o-continuity. Finally, new decompositions of continuity are provided.


Dynamic Composition Of Agent Grammars, Kyle Neumeier Jan 2006

Dynamic Composition Of Agent Grammars, Kyle Neumeier

Inquiry: The University of Arkansas Undergraduate Research Journal

In the very near future, as pervasive computing takes root, there will be an explosion of everyday objects that are uniquely identifiable and wrapped by a computational layer- effectively bringing the object to life. An important component of this system is the mechanism that will allow humans to interface with the objects. Menu Based Natural Language Interfaces (MBNLI) seem like a good candidate for this job because of the intuitive way in which they allow the user to build commands. However, the MBNLI system will have to scale with the number of objects in the system. This project describes context …


Cuoricino And Cuore Detectors: Developing Big Arrays Of Large Mass Bolometers For Rare Events Physics, P. Gorla, R. Ardito, C. Arnaboldi, D. R. Artusa, F. T. Avignone Iii, M. Balata, I. Bandac, M. Barucci, J. Beeman, C. Brofferio, C. Bucci, S. Capelli, F. Capozzi, L. Carbone, S. Cebrian, O. Cremonesi, R. J. Creswick, M. Dolinski, A. De Waard, H. A. Farach, F. Ferroni, E. Fiorini, G. Frossati, C. Gargiulo, A. Giuliani, E. Guardincerri, T. Gutierrez, E. E. Haller, I. G. Irastorza, E. Longo, G. Maier, R. Maruyama, R. J. Mcdonald, S. Morganti, A. Morales, S. Nisi, E. B. Norman, A. Nucciotti, E. Olivieri, P. Ottonello, M. Pallavicini, V. Palmieri, E. Pasca, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, B. Quiter, L. Risegari, C. Rosenfeld, S. Sangiorgio, M. Sisti, A. R. Smith, Toffanin, L. Torres, G. Ventura, N. Xu Jan 2006

Cuoricino And Cuore Detectors: Developing Big Arrays Of Large Mass Bolometers For Rare Events Physics, P. Gorla, R. Ardito, C. Arnaboldi, D. R. Artusa, F. T. Avignone Iii, M. Balata, I. Bandac, M. Barucci, J. Beeman, C. Brofferio, C. Bucci, S. Capelli, F. Capozzi, L. Carbone, S. Cebrian, O. Cremonesi, R. J. Creswick, M. Dolinski, A. De Waard, H. A. Farach, F. Ferroni, E. Fiorini, G. Frossati, C. Gargiulo, A. Giuliani, E. Guardincerri, T. Gutierrez, E. E. Haller, I. G. Irastorza, E. Longo, G. Maier, R. Maruyama, R. J. Mcdonald, S. Morganti, A. Morales, S. Nisi, E. B. Norman, A. Nucciotti, E. Olivieri, P. Ottonello, M. Pallavicini, V. Palmieri, E. Pasca, M. Pavan, M. Pedretti, G. Pessina, S. Pirro, E. Previtali, B. Quiter, L. Risegari, C. Rosenfeld, S. Sangiorgio, M. Sisti, A. R. Smith, Toffanin, L. Torres, G. Ventura, N. Xu

Physics

In the last 10 years bolometers have become extremely powerful detectors in the search for rare events, due to their very good resolution. Cuoricino, a 62 bolometer array, in the first months of activity reached a resolution (average in all detectors) in the energy region of interest (2528 keV) of 7 keV and a limit on the tn1/2 of the process of 7.5·10n23y. Cuoricino’s 62 detectors constitute the biggest number of macrobolometers (790 g each) ever cooled and demonstrate the feasibility of large arrays of bolometers. Following the indication of Cuoricino in CUORE R&D a new detector …


Factors Influencing Internal P Loading In A Western Michigan, Drowned River-Mouth Lake, Alan D. Steinman, Lori Nemeth, Eric Nemeth, Richard Rediske Jan 2006

Factors Influencing Internal P Loading In A Western Michigan, Drowned River-Mouth Lake, Alan D. Steinman, Lori Nemeth, Eric Nemeth, Richard Rediske

Peer-reviewed scientific publications

Originally published in: J. N. Am. Benthol. Soc., 2006, 25(2):304–312

Release of P from lake sediments may account for a significant portion of a lake’s total P (TP) load. Previous studies using sediment cores showed that ;65% of the total P load entering Spring Lake, Michigan, came from the sediments, and that an alum concentration of 24 mg Al/L effectively inactivated P release in experimental sediment-core tubes. In 2004, we studied the influence of alum concentration and sediment resuspension on P release rates from the sediments. Based on laboratory incubations using alum concentrations of 0, 5, 10, 15, 20, and …


Spanning Trails Containing Given Edges, Weiqi Luo, Zhi-Hong Chen, Wei-Guo Chen Jan 2006

Spanning Trails Containing Given Edges, Weiqi Luo, Zhi-Hong Chen, Wei-Guo Chen

Scholarship and Professional Work - LAS

A graph G is Eulerian-connected if for any u and v in V ( G ) , G has a spanning ( u , v ) -trail. A graph G is edge-Eulerian-connected if for any e ′ and e ″ in E ( G ) , G has a spanning ( e ′ , e ″ ) -trail. For an integer r ⩾ 0 , a graph is called r -Eulerian-connected if for any X ⊆ E ( G ) with | X | ⩽ r , and for any u , v ∈ V ( G ) , G …


Strain Accumulation Across The Carrizo Segment Of The San Andreas Fault, California: Impact Of Laterally Varying Crustal Properties, Gina Schmalzle, Timothy H. Dixon, Rocco Malservisi, Rob Govers Jan 2006

Strain Accumulation Across The Carrizo Segment Of The San Andreas Fault, California: Impact Of Laterally Varying Crustal Properties, Gina Schmalzle, Timothy H. Dixon, Rocco Malservisi, Rob Govers

School of Geosciences Faculty and Staff Publications

Major strike slip faults juxtapose geologically dissimilar terrain which may vary in mechanical properties, leading to an asymmetric pattern of strain accumulation. We present new GPS data on the Carrizo segment of the San Andreas Fault, separating the Salinian block southwest of the fault from Franciscan terrane northeast of the fault, to better quantify asymmetric strain accumulation. We also present a series of finite element models to investigate the possible role of variable elastic layer thickness and material properties of the upper crust. The geodetic data are well fit with a simple model comprising a weak upper crustal zone 10–25 …


Applications Of Computational Homology, Christopher Aaron Johnson Jan 2006

Applications Of Computational Homology, Christopher Aaron Johnson

Theses, Dissertations and Capstones

Homology is a field of topology that classifies objects based on the number of n- dimensional holes (cuts, tunnels, voids, etc.) they possess. The number of its real life ap- plications is quickly growing, which requires development of modern computational meth- ods. In my thesis, I will present methods of calculation, algorithms, and implementations of simplicial homology, alpha shapes, and persistent homology.

The Alpha Shapes method represents a point cloud as the union of balls centered at each point, and based on these balls, a complex can be built and homology computed. If the balls are allowed to grow, one …


A New Method For The Preparation Of Pyridazine Systems: Experimental Data And Semiempirical Pm3 Calculations, Di̇lek Ünal, Emi̇n Saripinar, Yunus Akçamur Jan 2006

A New Method For The Preparation Of Pyridazine Systems: Experimental Data And Semiempirical Pm3 Calculations, Di̇lek Ünal, Emi̇n Saripinar, Yunus Akçamur

Turkish Journal of Chemistry

The reactions of 4-benzoyl-5-phenyl-2,3-furandione (1a) and 4-(4-methoxybenzoyl)-5-(4-methoxyphenyl)-2,3-furandione (1b) with acyl hydrazines (2) (namely hydrazides) are reported. From these reactions, novel pyridazinone systems (3a-g) are obtained as well as the cyclization product of 3g at high temperature (4). The electronic properties and conformational parameters for these molecules, such as bond lengths, bond angles, torsion angles and atom charges, are calculated with a semiempirical PM3 method. In order to determine the mechanism of the reaction between the model furandion (R1) and formic hydrazide (R2), the electronic properties, conformational parameters and imaginary frequencies of the reactants, transition states and intermediates are calculated at …