Theoretical Calculation of MMF's Bandwidth
Institute of Scientific and Technical Information of China (English)
LI Xiao-fu; JIANG De-sheng; YU Hai-hu
2004-01-01
The difference between over-filled launch bandwidth (OFL BW) and restricted mode launch bandwidth (RML BW) is described. A theoretical model is founded to calculate the OFL BW of grade index multimode fiber (GI-MMF),and the result is useful to guide the modification of the manufacturing method.
Theoretical Calculations of Atomic Data for Spectroscopy
Bautista, Manuel A.
2000-01-01
Several different approximations and techniques have been developed for the calculation of atomic structure, ionization, and excitation of atoms and ions. These techniques have been used to compute large amounts of spectroscopic data of various levels of accuracy. This paper presents a review of these theoretical methods to help non-experts in atomic physics to better understand the qualities and limitations of various data sources and assess how reliable are spectral models based on those data.
Theoretical calculation of ozone vibrational infrared intensities
Adler-Golden, S. M.; Langhoff, S. R.; Bauschlicher, C. W., Jr.; Carney, G. D.
1985-01-01
An ab initio dipole moment function for ozone has been computed using the CASSCF (complete active space self-consistent field) method, and forms the basis for a calculation of ozone infrared band intensities. Vibrational wave functions were generated using the variational method with potential energy surfaces derived from experimental force constants. Computed values of the permanent dipole moment, dipole moment derivatives, and infrared band strengths are all found to be in remarkably good agreement with experiment. Intensities are predicted for hot bands for which experimental values are unavailable, and implications for atmospheric ozone spectroscopy are discussed. As the dipole moment matrix element signs are now established for nearly all of the observed bands, further refinement of the dipole moment function is possible.
Theoretical Model Calculation for d + 8Li Reaction
Institute of Scientific and Technical Information of China (English)
HAN Yin-Lu; GUO Hai-Rui; ZHANG Yue; ZHANG Jing-Shang
2008-01-01
Based on the theoretical models for light nuclei, the calculations of reaction cross sections and the angular distributions for d+8Li reaction are performed. Since all of the particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism is taken into account. The three-body break-up process and the recoil effect are involved. The theoretical calculated results are compared to existing experimental data.
Calculation of Theoretical Isotropic Compton Profile for Many Particle Systems
Alzubadi, Ali A.; Albayati, Khalil H.
Theoretical isotropic (spherically symmetric) Compton profiles (ICP) have been calculated for many particle systems' He, Li, Be and B atoms in their ground states. Our calculations were performed using Roothan-Hartree-Fock (RHF) wave function, HF wave function of Thakkar and re-optimized HF wave function of Clementi-Roetti, taking into account the impulse approximation. The theoretical analysis included a decomposition of the various intra and inter shells and their contributions in the total ICP. A high momentum region of up to 4 a.u. was investigated and a non-negligible tail was observed in all ICP curves. The existence of a high momentum tail was mainly due to the electron-electron interaction. The ICP for the He atom has been compared with the available experimental data and it is found that the ICP values agree very well with them. A few low order radial momentum expectation values and the total energy for these atomic systems have also been calculated and compared with their counterparts' wave functions.
Theoretical calculations on layered perovskites: implications for photocatalysis
Directory of Open Access Journals (Sweden)
Xiang Liu
2014-12-01
Full Text Available The application of first-principles calculations to the study of layered perovskites is reviewed here, with an emphasis on properties relevant to the use of these materials in photocatalysis. First, the accuracies of the theoretical methods in common use for the study of layered perovskites are compared. The main body of the article then reviews studies of the bulk atomic and electronic structures of pure and doped perovskites; first-principles thermodynamics studies; studies of surfaces and studies of adsorption on surfaces.
The 239 Pu(n,2n)238Pu cross section: preliminary calculations
Energy Technology Data Exchange (ETDEWEB)
Chen, H; Reffo, G; Ross, M A; White, R M
1999-03-12
The primary motivation for the present work is to provide theoretical values for the ratio of the partial ^{239}Pu(n,2nx{gamma})^{238}Pu to total ^{239} Pu(n,2n)^{238}Pu cross section for several discrete gamma transitions. Results and conclusions of preliminary calculations from threshold to 20 MeV are presented. Calculations are based on theoretical models with parameters obtained from the literature or from our ad hoc systematics. Optical model cross sections and transmission coefficients were determined using the coupled-channels method. The calculations included a preequilibrium component followed by multiple particle and gamma-ray emissions. Fission competition was included at all stages of de-excitation. Suggestions for further verifications and possible improvements are provided.
Preliminary Calculation on a Spent Fuel Pool Accident using GOTHIC
Energy Technology Data Exchange (ETDEWEB)
Park, Jaehwan; Choi, Yu Jung; Hong, Tae Hyub; Kim, Hyeong-Taek [KHNP-CRI, Daejeon (Korea, Republic of)
2015-10-15
The probability of an accident happening at the spent fuel pool was believed to be quite low until the 2011 Fukushima accident occurred. Notably, large amount of spent fuel are normally stored in the spent fuel pool for a long time compared to the amount of fuel in the reactor core and the total heat released from the spent fuel is high enough to boil the water of the spent fuel pool when the cooling system does not operate. In addition, the enrichment and the burnup of the fuel have both increased in the past decade and heat generation from the spent fuel thereby has also increased. The failure of the cooling system at the spent fuel pool (hereafter, a loss-of-cooling accident) is one of the principal hypothetical causes of an accident that could occur at the spent fuel pool. In this paper, the preliminary calculation of a loss-of-cooling accident was performed. In this paper, the preliminary calculation of a loss-of cooling accident was performed with GOTHIC. The calculation results show boiling away of water in the spent fuel pool due to the loss-of-cooling accident and similar thermal performance of the spent fuel pool with previous research results.
THEORETICAL CALCULATION OF THE RELATIVISTIC SUBCONFIGURATION-AVERAGED TRANSITION ENERGIES
Institute of Scientific and Technical Information of China (English)
张继彦; 杨向东; 杨国洪; 张保汉; 雷安乐; 刘宏杰; 李军
2001-01-01
A method for calculating the average energies of relativistic subconfigurations in highly ionized heavy atoms has been developed in the framework of the multiconfigurational Dirac-Fock theory. The method is then used to calculate the average transition energies of the spin-orbit-split 3d-4p transition of Co-like tungsten, the 3d-5f transition of Cu-like tantalum, and the 3d-5f transitions of Cu-like and Zn-like gold samples. The calculated results are in good agreement with those calculated with the relativistic parametric potential method and also with the experimental results.
Theoretical calculation for magnetometric sensor based in anhysteretic processes
Energy Technology Data Exchange (ETDEWEB)
Garcia, A.; Moron, C. E-mail: cmoron@eui.upm.es; Carracedo, M.T
2003-01-01
In this work, we present a theoretical study to measure weak magnetic field based on measurements of anhysteretic states of a ferromagnetic nucleus. In order to improve this magnetometric sensor, cores of amorphous ribbons with different characteristics have been tested. The sensitivity of this device exhibits a great dependence on the magnetic anisotropy distribution of the core. The theoretical curves obtained are in good agreement with the experimental results, except in the proximity to zero field, where the magnetization processes are mainly due to domain walls displacements.
Field-theoretic calculation of kinetic helicity flux
Indian Academy of Sciences (India)
V Avinash; Mahendra K Verma; Amar K Chandra
2006-02-01
In this paper we apply perturbative field-theoretic technique to helical turbulence. In the inertial range the kinetic helicity flux is found to be constant and forward. The universal constant H appearing in the spectrum of kinetic helicity was found to be 2.47.
Theoretical and methodical support of calculating expenses for quality
Пархоменко, Валерій Миколайович
2015-01-01
A hybrid models of calculating expenses for quality on the full life cycle in combination with types of expenses on purpose and model of goods costing considering expenses for quality by standard-functional method have been developed.
Theoretical calculations of hyperfine coupling constants for muoniated butyl radicals.
Chen, Ya Kun; Fleming, Donald G; Wang, Yan Alexander
2011-04-01
The hyperfine coupling constants (HFCCs) of all the butyl radicals that can be produced by muonium (Mu) addition to butene isomers (1- and 2-butene and isobutene) have been calculated, to compare with the experimental results for the muon and proton HFFCs for these radicals reported in paper II (Fleming, D. G.; et al. J. Phys. Chem. A 2011, 10.1021/jp109676b) that follows. The equilibrium geometries and HFCCs of these muoniated butyl radicals as well as their unsubstituted isotopomers were treated at both the spin-unrestricted MP2/EPR-III and B3LYP/EPR-III levels of theory. Comparisons with calculations carried out for the EPR-II basis set have also been made. All calculations were carried out in vacuo at 0 K only. A C-Mu bond elongation scheme that lengthens the equilibrium C-H bond by a factor of 1.076, on the basis of recent quantum calculations of the muon HFCCs of the ethyl radical, has been exploited to determine the vibrationally corrected muon HFCCs. The sensitivity of the results to small variations around this scale factor was also investigated. The computational methodology employed was "benchmarked" in comparisons with the ethyl radical, both with higher level calculations and with experiment. For the β-HFCCs of interest, compared to B3LYP, the MP2 calculations agree better with higher level theories and with experiment in the case of the eclipsed C-Mu bond and are generally deemed to be more reliable in predicting the equilibrium conformations and muon HFCCs near 0 K, in the absence of environmental effects. In some cases though, the experimental results in paper II demonstrate that environmental effects enhance the muon HFCC in the solid phase, where much better agreement with the experimental muon HFCCs near 0 K is found from B3LYP than from MP2. This seemingly better level of agreement is probably fortuitous, due to error cancellations in the DFT calculations, which appear to mimic these environmental effects. For the staggered proton HFCCs of the
The confusion technique untangled: its theoretical rationale and preliminary classification.
Otani, A
1989-01-01
This article examines the historical development of Milton H. Erickson's theoretical approach to hypnosis using confusion. Review of the literature suggests that the Confusion Technique, in principle, consists of a two-stage "confusion-restructuring" process. The article also attempts to categorize several examples of confusion suggestions by seven linguistic characteristics: (1) antonyms, (2) homonyms, (3) synonyms, (4) elaboration, (5) interruption, (6) echoing, and (7) uncommon words. The Confusion Technique is an important yet little studied strategy developed by Erickson. More work is urged to investigate its nature and properties.
Theoretical calculations and analysis for n + 6Li reaction
Tao, Xi; Wang, Jimin; Chen, Guochang; Shen, Qingbiao
2017-09-01
R-matrix theory is an important methodology for applications on light, medium and heavy mass nuclides nuclear reaction in the resonance energy range. Full R-matrix formalism contains the diagonal elements of the energy levels matrix and it is a rigorous theory. Because of different assumptions and approximations, many kinds of R-matrix derived methods are obtained. The new R-matrix code FDRR is presented and includes 4 kinds of R-matrix applications. It can be used for calculating integral cross sections and angular distributions of 2-bodies reactions. The cross sections and angular distributions of n+ 6Li reaction are calculated and analyzed by FDRR code. The results are in good agreement with experimental data below 20 MeV.
Directory of Open Access Journals (Sweden)
Anderson Tiago Peixoto Gonçalves
2016-08-01
Full Text Available This theoretical essay aims to reflect on three models of text interpretation used in qualitative research, which is often confused in its concepts and methodologies (Content Analysis, Discourse Analysis, and Conversation Analysis. After the presentation of the concepts, the essay proposes a preliminary discussion on conceptual and theoretical methodological differences perceived between them. A review of the literature was performed to support the conceptual and theoretical methodological discussion. It could be verified that the models have differences related to the type of strategy used in the treatment of texts, the type of approach, and the appropriate theoretical position.
Institute of Scientific and Technical Information of China (English)
SONG; Ming-zhe; WEI; Ke-xin; HOU; Jin-bing; WANG; Hong-yu; GAO; Fei; NI; Ning
2015-01-01
The Bragg-Gray cavity theory(B-G theory)provided a theoretical basis for the analytical calculation of the energy response for ionization chamber.It was widely used in the theoretical calculation of the ionization chamber detector and the tissue equivalent detector.However,the B-G
Calorimetric determinations and theoretical calculations of polymorphs of thalidomide
Lara-Ochoa, F.; Pérez, G. Espinosa; Mijangos-Santiago, F.
2007-09-01
The analysis of the thermograms of thalidomide obtained for the two reported polymorphs α and β by differential scanning calorimetry (DSC) shows some inconsistencies that are discussed in the present work. The conception of a new polymorph form, named β ∗, allowed us to explain the observed thermal behavior more satisfactorily. This new polymorph shows enantiotropy with both α and β polymorphs, reflected in the unique endotherm obtained in the DSC-thermograms, when a heating rate of 10 °C/min is applied. Several additional experiments, such as re-melting of both polymorph forms, showed that there is indeed a new polymorph with an endotherm located between the endotherms of α and β. IR, Raman, and powder X-ray permit us to characterize the isolated compound, resulting from the re-melting of both polymorph forms. Mechanical calculations were performed to elucidate the conformations of each polymorph, and ab initio quantum chemical calculations were performed to determine the energy of the more stable conformers and the spatial cell energy for both polymorphs α and β. These results suggested a possible conformation for the newly discovered polymorph β ∗.
Molecular Structure, Theoretical Calculation and Thermodynamic Properties of Tebuconazole
Institute of Scientific and Technical Information of China (English)
MA Haixia; SONG Jirong; HUANG Ting; LU Xingqiang; XU Kangzhen; SUN Xiaohong
2009-01-01
Single crystals of 5-(4-chlorophenyl)-2,2-dimethyl-3-(1,2,4-triazol-1-ylmethyl)-pentom-3-ol (tebuconazole) were obtained in toluene. The single-crystal X-ray diffraction studies showed that it crystallized in the monoclinic system, with space group P2(1)/c and crystal parameters of a= 1.1645(1) nm, b= 1.6768(2) nm, c= 1.7478(2) nm,β=92.055(2)°, Dc= 1.199 g/cm3, Z=4 and F(000)= 1312. Density functional theory (DFT) B3LYP was employed to optimize the structure and calculate the frequencies of tebuconazole. The calculated geometrical parameters are close to the corresponding experimental ones. The specific heat capacity of the title compound was determined with continuous Cp mode of a mircocalorimeter. In the determining temperature range from 283 to 353 K, the special heat capacity of the title compound presents good linear relation with temperature. Using the determined relation-ship of Cp with temperature T, thermodynamic functions (enthalpy, entropy and Gibbs free energy) of the title compound between 283 and 353 K, relative to the standard temperature 298.15 K, were derived through thermody-namic relationship.
Metabolic engineering from a cybernetic perspective. 1. Theoretical preliminaries
Varner; Ramkrishna
1999-05-01
The theoretical basis of a cybernetic metabolic network design and analysis framework, which has been subsequently successfully applied to predict system response to genetic alteration, is presented. This conceptual methodology consists of three main branches, namely, a model realization framework, a representation of genetic alteration, and lastly, a metabolic design component. These concepts are introduced as a series of postulates that describe the basic tenets of the approach. Each branch is discussed in turn, starting with the cybernetic representation of arbitrarily complex metabolic networks. A set of postulates is put forth that affords the modular construction of cybernetic models of metabolic networks using as a base a library of elementary pathways. This is followed by a discussion of the representation of genetic alterations within the cybernetic framework. It is postulated that the objective of the base network and the altered system are identical (at least on the time scale required for the organism to "learn" new objectives). This implies, with respect to resource allocation, that the base network and its genetically altered counterpart may still be treated as optimal systems; however, the set of competing physiological choices open to the altered network expands or contracts depending upon the nature of the genetic perturbation. Lastly, to add a predictive design aspect to the methodology, we present a set of postulates that outline the application of metabolic control analysis to cybernetic model systems. We postulate that sensitivity coefficients computed from a cybernetic model, although still local in scope, have the added benefit of a systematic representation of regulatory function as described by the cybernetic variables. Thus, information gained from sensitivity measurements stemming from a cybernetic model include the explicit input of metabolic regulation, a component that is lacking in a purely kinetic representation of metabolic function
Theoretical Calculation on Optimum Si-doping Content in Boron Carbide Thin Film
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
The theoretical expression of the relationship between optimum doping content and crystal structure is presented as well as the preparation methods. By using this expression, the optimum doping content of silicon-doped boron carbide thin film is calculated. The quantitative calculation value is consistent with the experimental results. This theoretical expression is also appropriate to resolve the optimum doping content for other electric materials.
Preliminary skyshine calculations for the Poloidal Diverter Tokamak Experiment
Nigg, D. W.; Wheeler, F. J.
1981-01-01
A calculational model is presented to estimate the radiation dose, due to the skyshine effect, in the control room and at the site boundary of the Poloidal Diverter Experiment (PDX) facility at Princeton University which requires substantial radiation shielding. The required composition and thickness of a water-filled roof shield that would reduce this effect to an acceptable level is computed, using an efficient one-dimensional model with an Sn calculation in slab geometry. The actual neutron skyshine dose is computed using a Monte Carlo model with the neutron source at the roof surface obtained from the slab Sn calculation, and the capture gamma dose is computed using a simple point-kernel single-scatter method. It is maintained that the slab model provides the exact probability of leakage out the top surface of the roof and that it is nearly as accurate as and much less costly than multi-dimensional techniques.
Energy Technology Data Exchange (ETDEWEB)
Kripal, Ram, E-mail: ram_kripal2001@rediffmail.com; Yadav, Awadhesh Kumar, E-mail: aky.physics@gmail.com
2015-06-15
Zero field splitting parameters (ZFSPs) D and E of Cr{sup 3+} ion doped ammonium oxalate monohydrate (AOM) are calculated with formula using the superposition model. The theoretically calculated ZFSPs for Cr{sup 3+} in AOM crystal are compared with the experimental value obtained by electron paramagnetic resonance (EPR). Theoretical ZFSPs are in good agreement with the experimental ones. The energy band positions of optical absorption spectra of Cr{sup 3+} in AOM crystal calculated with CFA package are in good match with the experimental values.
Theoretical Calculation and Analysis of Slip and Deformation for Concrete Sandwich Panels
Institute of Scientific and Technical Information of China (English)
LI Yanbo; ZHANG Shaohua; XIA Baoyang
2007-01-01
Slip and deformation of concrete sandwich panels under uniformly distributed loads is concerned. The effect of slip on the deformation of concrete sandwich panels are studied, and the analytical expressions of slip and deformation for concrete sandwich panels is obtained. These formulae can describe the slip distribution and account for its effect on deformation. In order to restrict the bound of formula, the formula of crack moment is obtained. The results of theoretical calculation are compared with those of tests and finite element methods. The comparison shows that the results of theoretical calculation are in accord with those of tests and finite element methods. So the theoretical calculation can be used to calculate slip and deformation of concrete sandwich panels in practical projects.
Parallel processing of atmospheric chemistry calculations: Preliminary considerations
Energy Technology Data Exchange (ETDEWEB)
Elliott, S.; Jones, P.
1995-01-01
Global climate calculations are already saturating the class modern vector supercomputers with only a few central processing units. Increased resolution and inclusion of routines to deal with biogeochemical portions of the terrestrial climate system will soon demand massively parallel approaches. The atmospheric photochemistry ensemble is intimately linked to climate through the trace greenhouse gases ozone and methane and modules for representing it are being attached to global three dimensional transport and GCM frameworks. Atmospheric kinetics involve dozens of highly interactive tracers and so will accentuate the need for parallel processing of earth system simulations. In the present text we lay some of the groundwork for addition of atmospheric kinetics packages to GCM and global scale atmospheric models on multiply parallel computers. The discussion is tailored for consumption by the photochemical modelling community. After a review of numerical atmospheric chemistry methods, we examine how kinetics can be implemented on a parallel computer. We concentrate especially on data layout and flexibility and how these can be implemented in various programming models. We conclude that chemistry can be implemented rather easily within existing frameworks of several parallel atmospheric models. However, memory limitations may preclude high resolution studies of global chemistry.
Sneck, Sami; Saarnio, Reetta; Isola, Arja; Boigu, Risto
2016-01-01
Medication administration is an important task of registered nurses. According to previous studies, nurses lack theoretical knowledge and drug calculation skills and knowledge-based mistakes do occur in clinical practice. Finnish health care organizations started to develop a systematic verification processes for medication competence at the end of the last decade. No studies have yet been made of nurses' theoretical knowledge and drug calculation skills according to these online exams. The aim of this study was to describe the medication competence of Finnish nurses according to theoretical and drug calculation exams. A descriptive correlation design was adopted. Participants and settings All nurses who participated in the online exam in three Finnish hospitals between 1.1.2009 and 31.05.2014 were selected to the study (n=2479). Quantitative methods like Pearson's chi-squared tests, analysis of variance (ANOVA) with post hoc Tukey tests and Pearson's correlation coefficient were used to test the existence of relationships between dependent and independent variables. The majority of nurses mastered the theoretical knowledge needed in medication administration, but 5% of the nurses struggled with passing the drug calculation exam. Theoretical knowledge and drug calculation skills were better in acute care units than in the other units and younger nurses achieved better results in both exams than their older colleagues. The differences found in this study were statistically significant, but not high. Nevertheless, even the tiniest deficiency in theoretical knowledge and drug calculation skills should be focused on. It is important to identify the nurses who struggle in the exams and to plan targeted educational interventions for supporting them. The next step is to study if verification of medication competence has an effect on patient safety. Copyright © 2015 Elsevier Ltd. All rights reserved.
Kuwada, Takeshi; Fukui, Miyako; Hata, Toshiyuki; Choshi, Tominari; Nobuhiro, Junko; Ono, Yukio; Hibino, Satoshi
2003-01-01
The specific optical rotations of (R)-oxopropaline D calculated by two ab initio MO methods were +52+/-31 degrees and +61+/-29 degrees, respectively, and (+)-oxopropaline D (3) was presumed to have an R-configuration. On the basis of this theoretical result, the reaction of 1-litio-beta-carboline with (R)-glyceraldehyde acetonide followed by oxidation with MnO(2) gave (R)-oxopropaline D acetonide (4a), which was consistent with the previously synthesized (+)-oxopropaline D acetonide (4) in all respects. From the results of theoretical calculations and the experimental synthesis, we determined that natural (+)-oxopropaline D (3) has an R-configuration.
Theoretical Calculation of Rotational Bands of 179Pt in the Particle-Triaxial-Rotor Model
Institute of Scientific and Technical Information of China (English)
CHEN Guo-Jie; SONG Hui-Chao; LIU Yu-Xin
2005-01-01
Theoretical calculations have been performed for nucleus 179Pt in the particle-triaxial-rotor model with variable moment of inertia. The obtained energy spectrum agrees with the experimental data quite well. The calculated results indicate that the bands 1/2- and 7/2+ are triaxial deformation bands and originate mainly from the v[521]1/2- and v[633]7/2+ configurations respectively.
Orwat, Justyna; Mielimaka, Ryszard
2016-06-01
The article demonstrates the comparison of prognosed values of deformation indicators with their values obtained from geodetic measurements. The value of correlation coefficient R between its theoretical and practical values was calculated for each indicator. Following the measured values as basic ones, the evaluation of efficiency of prognosis via the use of Knothe`s theory (a mathematical model, in which lowering of point is calculated as a double integral from Gauss error function with adequate parameters).
Energy Technology Data Exchange (ETDEWEB)
Baguena, A.; Shaw, M.; Williart, A. [Universidad Nacional de Educacion a Distancia, Dpto. Fisica de los Materiales, Madrid (Spain); Baguena, A. [Consejo de Seguridad Nuclear, Madrid (Spain); Garcia, G. [Instituto de Matematicas y Fisica Fundamental, Consejo Superior de Investigaciones Cientificas, Madrid (Spain)
2006-07-01
We describe the calculations and preliminary measures made for the installation of a X-ray generator tube. This device is going to be used for the secondary electron production from photonic primary radiation of up to 125 keV. With this experimental system, we will study the energetic and space distribution of produced secondary electrons by obtaining its spectrum of energies and its angular distribution. This method of measurement is going to be applied in different targets of radiological, environmental and biological interest. Calculations in the present article include: theoretical yield of X-rays production of the designed equipment, necessary shielding for the radiological safety of the installation staff, and an estimated dose due to their use. Characteristics of the installation and the equipment are described with this purpose. (author)
Time-dependent density functional theory (TDDFT) was employed for theoretical calculation of electronic circular dichroism (ECD) of a hexahydroxydiphenoyl (HHDP)-containing flavanone glycoside, mattucinol-7-O-[4'',6''-O-(aS)-hexahydroxydiphenoyl]-ß-d-glucopyranoside (2). It identified the roles of t...
MR imaging of prostate. Preliminary experience with calculated imaging in 28 cases
Energy Technology Data Exchange (ETDEWEB)
Gevenois, P.A.; Van Regemorter, G.; Ghysels, M.; Delepaut, A.; Van Gansbeke, D.; Struyven, J.
1988-04-01
The majority of studies with MR imaging in prostate disease are based on a semiology obtained using images weighted in T1 and T2. A study was carried out to evaluate effects of images calculated in T1 and T2 obtained at 0.5T. This preliminary study concerns 28 prostate examinations with spin-echo acquisition and inversion-recuperation parameters, and provided images calculated in T1, weighted and calculated in T2. Images allowed detection and characterization of prostate lesions. However, although calculated images accentuate discrimination of the method, the weighted images conserve their place because of their improved spatial resolution.
Energy Technology Data Exchange (ETDEWEB)
Decossas, J.L.; Vareille, J.C.; Moliton, J.P.; Teyssier, J.L. (Limoges Univ., 87 (France). Lab. d' Electronique des Polymeres sous Faisceaux Ioniques)
1983-01-01
A fast neutron dosemeter is generally composed of a radiator in which n-p elastic scattering occurs and a detector which registers protons. A theoretical study, and the calculation (FORTRAN program) of the response of such a dosemeter is presented involving two steps: 1) The proton flux emerging from a thick radiator on which monoenergetic neutrons are normally incident is studied. This is characterised by its energy spectrum depending on the neutron energy and on the radiator thickness. 2) Proton detection being achieved with a solid state nuclear track detector whose performance is known, the number of registered tracks are calculated. The dosemeter sensitivity (tracks cm/sup -2/. Sv/sup -1/) is deduced. Then, the calculations show that it is possible to optimise the radiator thickness to obtain the smallest variation in sensitivity with neutron energy. The theoretical results are in good agreement with the experimental ones found in the literature.
Theoretical Calculation of Absolute Radii of Atoms and Ions. Part 1. The Atomic Radii
Directory of Open Access Journals (Sweden)
Raka Biswas
2002-02-01
Full Text Available Abstract. A set of theoretical atomic radii corresponding to the principal maximum in the radial distribution function, 4ÃÂ€r2R2 for the outermost orbital has been calculated for the ground state of 103 elements of the periodic table using Slater orbitals. The set of theoretical radii are found to reproduce the periodic law and the Lother MeyerÃ¢Â€Â™s atomic volume curve and reproduce the expected vertical and horizontal trend of variation in atomic size in the periodic table. The d-block and f-block contractions are distinct in the calculated sizes. The computed sizes qualitatively correlate with the absolute size dependent properties like ionization potentials and electronegativity of elements. The radii are used to calculate a number of size dependent periodic physical properties of isolated atoms viz., the diamagnetic part of the atomic susceptibility, atomic polarizability and the chemical hardness. The calculated global hardness and atomic polarizability of a number of atoms are found to be close to the available experimental values and the profiles of the physical properties computed in terms of the theoretical atomic radii exhibit their inherent periodicity. A simple method of computing the absolute size of atoms has been explored and a large body of known material has been brought together to reveal how many different properties correlate with atomic size.
Shembel, Adrianna C; Sandage, Mary J; Verdolini Abbott, Katherine
2017-01-01
The purposes of this literature review were (1) to identify and assess frameworks for clinical characterization of episodic laryngeal breathing disorders (ELBD) and their subtypes, (2) to integrate concepts from these frameworks into a novel theoretical paradigm, and (3) to provide a preliminary algorithm to classify clinical features of ELBD for future study of its clinical manifestations and underlying pathophysiological mechanisms. This is a literature review. Peer-reviewed literature from 1983 to 2015 pertaining to models for ELBD was searched using Pubmed, Ovid, Proquest, Cochrane Database of Systematic Reviews, and Google Scholar. Theoretical models for ELBD were identified, evaluated, and integrated into a novel comprehensive framework. Consensus across three salient models provided a working definition and inclusionary criteria for ELBD within the new framework. Inconsistencies and discrepancies within the models provided an analytic platform for future research. Comparison among three conceptual models-(1) Irritable larynx syndrome, (2) Dichotomous triggers, and (3) Periodic occurrence of laryngeal obstruction-showed that the models uniformly consider ELBD to involve episodic laryngeal obstruction causing dyspnea. The models differed in their description of source of dyspnea, in their inclusion of corollary behaviors, in their inclusion of other laryngeal-based behaviors (eg, cough), and types of triggers. The proposed integrated theoretical framework for ELBD provides a preliminary systematic platform for the identification of key clinical feature patterns indicative of ELBD and associated clinical subgroups. This algorithmic paradigm should evolve with better understanding of this spectrum of disorders and its underlying pathophysiological mechanisms. Copyright © 2017 The Voice Foundation. Published by Elsevier Inc. All rights reserved.
Paz-Garcia, J M; Schaetzle, O; Biesheuvel, P M; Hamelers, H V M
2014-03-15
Recently, a new technology has been proposed for the utilization of energy from CO2 emissions (Hamelers et al., 2014). The principle consists of controlling the dilution process of CO2-concentrated gas (e.g., exhaust gas) into CO2-dilute gas (e.g., air) thereby extracting a fraction of the released mixing energy. In this paper, we describe the theoretical fundamentals of this technology when using a pair of charge-selective capacitive electrodes. We focus on the behavior of the chemical system consisting of CO2 gas dissolved in water or monoethanolamine solution. The maximum voltage given for the capacitive cell is theoretically calculated, based on the membrane potential. The different aspects that affect this theoretical maximum value are discussed.
Institute of Scientific and Technical Information of China (English)
JIANG Xu-bao; ZHU Xiao-li; ZHANG Zhi-guo; KONG Xiang-zheng; TAN Ye-bang
2011-01-01
A theoretical method to calculate the mode of polyurethane(PU) prepolymers grafted to polyacrylic(PAC) was presented. Using hydroxyethyl acrylate(HEA) as coupling agent, polyurethane-acrylics(PU-AC) hybrid latexes were prepared with varying HEA level and the reaction of HEA with PU prepolymers at different temperatures, and PU grafted to PAC was experimentally determined. The results show that PU grafted to PAC regularly increased, and the non-grafted and linear free PU regularly decreased with increase in HEA/NCO(isocyanate group). The grafted PU on PAC was not proportional to HEA. More than half of linear PU prepolymers were grafted to PAC when HEA was at a low level with HEA/NCO at 0.33. While grafted PU increased to 84.80％ (mass fraction), when HEA/NCO increased to 1.0. The results were interpreted based on the theoretical calculation of PU grafted to PAC by the present method.
Improvements on Calculation Model of Theoretical Combustion Temperature in a Blast Furnace
Institute of Scientific and Technical Information of China (English)
WU Sheng-li; LIU Cheng-song; FU Chang-liang; XU Jian; KOU Ming-yin
2011-01-01
On the basis of the existing originally modified calculation models of theoretical combustion temperature（TCT）,some factors,such as the combustion ratio of pulverized coal injection（PCI）,the decomposition heat of PCI and the heat consumption of SiO2 in ash reduced in high temperature environment,were amended and improved to put forward a more comprehensive model for calculating TCT.The influences of each improvement on TCT were studied and the results were analyzed compared with those of traditional model and originally modified model,which showed that the present model could reflect the thermal state of a hearth more effectively.
Hyun-Kyung Chung; Per Jönsson; Alexander Kramida
2013-01-01
Atomic structure and transition probabilities are fundamental physical data required in many fields of science and technology. Atomic physics codes are freely available to other community users to generate atomic data for their interest, but the quality of these data is rarely verified. This special issue addresses estimation of uncertainties in atomic structure and transition probability calculations, and discusses methods and strategies to assess and ensure the quality of theoretical atomic...
Theoretical calculation of mid-infrared spectra from hypersonic non-ablative sphere
Wu, Jie; Yu, Xilong; Zhu, Xijuan; Ma, Jing; Mao, Hongxia
2016-10-01
Hypersonic body moving in the atmosphere will suffer high temperature reacting flows which will emit complex radiation. Theoretical calculation was taken in this paper for a hypersonic non-ablative sphere. Hypersonic flow around the sphere was simulated using 9 species chemical kinetic and two temperature thermal non-equilibrium model. Based on this simulated flow field, the LOS method is used to solve radiative transfer and line-by-line model is used to calculate the spectrum from molecular and atoms in mid-infrared. The spectra from different components have been analyzed one by one. The calculation founds out that atom N and O diatomic molecule NO and bremsstrahlung will be important radiation source in this pure air hypersonic flow field. The radiation from hypersonic flow field has been analyzed in both high pressure environment and low pressure environment.
Verification of EPA's " Preliminary remediation goals for radionuclides" (PRG) electronic calculator
Energy Technology Data Exchange (ETDEWEB)
Stagich, B. H. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
2017-03-29
The U.S. Environmental Protection Agency (EPA) requested an external, independent verification study of their “Preliminary Remediation Goals for Radionuclides” (PRG) electronic calculator. The calculator provides information on establishing PRGs for radionuclides at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites with radioactive contamination (Verification Study Charge, Background). These risk-based PRGs set concentration limits using carcinogenic toxicity values under specific exposure conditions (PRG User’s Guide, Section 1). The purpose of this verification study is to ascertain that the computer codes has no inherit numerical problems with obtaining solutions as well as to ensure that the equations are programmed correctly.
Energy Technology Data Exchange (ETDEWEB)
Dickerson, M.H.
1980-08-01
ARAC was on-line calculating hourly concentration values during the TMI-2 venting of /sup 85/Kr gas from June 28 to July 11, 1980. During this time hourly isopleths of normalized instantaneous concentration were calculated and transmitted to EPA in Middletown, PA. These isopleths were used to help locate the EPA and Penn State mobile air samplers and they were used for comparison to the EPA fixed 24 hr sampler measurements and the DOE helicopter measurements. This report summarizes preliminary comparisons for the EPA fixed samplers and the DOE helicopters.
Energy Technology Data Exchange (ETDEWEB)
Zhu, Jinhua; Fu, Qingshan; Xue, Yongqiang, E-mail: xyqlw@126.com; Cui, Zixiang
2017-05-01
Based on the surface pre-melting model, accurate thermodynamic relations of the melting temperature of nanocrystals with different shapes (tetrahedron, cube, octahedron, dodecahedron, icosahedron, nanowire) were derived. The theoretically calculated melting temperatures are in relative good agreements with experimental, molecular dynamic simulation and other theoretical results for nanometer Au, Ag, Al, In and Pb. It is found that the particle size and shape have notable effects on the melting temperature of nanocrystals, and the smaller the particle size, the greater the effect of shape. Furthermore, at the same equivalent radius, the more the shape deviates from sphere, the lower the melting temperature is. The value of melting temperature depression of cylindrical nanowire is just half of that of spherical nanoparticle with an identical radius. The theoretical relations enable one to quantitatively describe the influence regularities of size and shape on the melting temperature and to provide an effective way to predict and interpret the melting temperature of nanocrystals with different sizes and shapes. - Highlights: • Accurate relations of T{sub m} of nanocrystals with various shapes are derived. • Calculated T{sub m} agree with literature results for nano Au, Ag, Al, In and Pb. • ΔT{sub m} (nanowire) = 0.5ΔT{sub m} (spherical nanocrystal). • The relations apply to predict and interpret the melting behaviors of nanocrystals.
Theoretical Calculation Model of Single Rip Tearing Strength for the Nonwoven Composites
Institute of Scientific and Technical Information of China (English)
QIAN Cheng
2005-01-01
The nonwoven composites have sandwich structure, with the first and third layers being nonwovens and the middle layer of woven fabric. On the basis of tests of the single rip tearing strength and drawing out resistances of both the nonwoven composites and the woven fabric, the single rip tearing failure mechanism of the composites were analyzed.Then theoretical calculation model for the single rip tearing strength was established, which indicates that the breaking strength of warp and weft yarns in the nonwoven composites, the density of warp and weft yarns and drawing out resistances are the main influencing factors. In the end,experimental verification was made, which shows that theoretical values conform to the measured values well.
García-Granados, A; Melguizo, E; Parra, A; Simeó, Y; Viseras, B; Dobado, J A; Molina, J; Arias, J M
2000-12-01
Different lipase enzymes have been tested in order to perform regioselective acetylations on the eudesmane tetrol from vulgarin. High yields (95%) of 1,12-diacetoxy derivative (4) were achieved in 1 h with Candida antarctica lipase (CAL). However, only the 12-acetyl derivative (6) was obtained in similar yield with Mucor miehei (MML) or Candida cylindracea (CCL) lipases. The enzymatic protection at C-1 and C-12 has been used to form eudesmane cyclic-sulfites between C-6 and C-4 atoms. The R/S-sulfur configuration has been assigned by means of the experimental and theoretical (13)C and (1)H NMR chemical shifts. The theoretical shifts were calculated using the GIAO method, with a MM+ geometry optimization followed by a single-point calculation at the B3LYP/6-31G(*) level (B3LYP/6-31G(*)//MM+). Moreover, B3LYP/6-31G(*) geometry optimizations were carried out to test the B3LYP/6-31G(*)//MM+ results, for the deacetylated sulfites (12 and 15). In addition to the delta(C) and delta(H) shifts, the (3)J(HH) coupling constants were also calculated and compared with the experimental values when available. Finally, different reactivities have been checked in both sulfites by biotransformation with Rhizopus nigricans. While the R-sulfite gave 2 alpha- and 11 beta-hydroxylated metabolites, the S-sulfite yielded only regioselective deacetylations. Furthermore, both sulfites showed different reactivities in redox processes.
Michalska, Katarzyna; Mizera, Mikołaj; Lewandowska, Kornelia; Cielecka-Piontek, Judyta
2016-07-01
Tedizolid is the newest antibacterial agent from the oxazolidinone class. For its identification, FT-IR (2000-400 cm-1) and Raman (2000-400 cm-1) analyses were proposed. Studies of the enantiomeric purity of tedizolid were conducted based on ultraviolet-circular dichroism (UV-CD) analysis. Density functional theory (DFT) with the B3LYP hybrid functional and 6-311G(2df,2pd) basis set was used for support of the analysis of the FT-IR and Raman spectra. Theoretical methods made it possible to conduct HOMO and LUMO analysis, which was used to determine the charge transfer for two tedizolid enantiomers. Molecular electrostatic potential maps were calculated with the DFT method for both tedizolid enantiomers. The relationship between the results of ab initio calculations and knowledge about the chemical-biological properties of R- and S-tedizolid enantiomers is also discussed.
Theoretical Calculations of Transition Probabilities and Oscillator Strengths for Sc(Ⅲ) and Y(Ⅲ)
Institute of Scientific and Technical Information of China (English)
Tian-yi Zhang; Neng-wu Zheng
2009-01-01
The Weakest Bound Electron Potential Model theory is used to calculate transition probability-values and oscillator strength-values for individual lines of Sc(Ⅲ) and Y(Ⅲ). In this method, by solving the SchrSdinger equation of the weakest bound electron, the expressions of energy eigenvalue and the radial function can be obtained. And a coupled equation is used to determine the parameters which are needed in the calculations. The ob-tained results of Sc(Ⅲ) from this work agree very well with the accepted values taken from the National Institute of Standards and Technoligy (NIST) data base, most deviations are within the accepted level. For Y(Ⅲ) there are no accepted values reported by the NIST data base. So we compared our results of Y(Ⅲ) with other theoretical results, good agreement is also obtained.
Vagena, E.; Stoulos, S.
2017-01-01
Bremsstrahlung photon beam delivered by a linear electron accelerator has been used to experimentally determine the near threshold photonuclear cross section data of nuclides. For the first time, (γ, n) cross section data was obtained for the astrophysical important nucleus 162Er. Moreover, theoretical calculations have been applied using the TALYS 1.6 code. The effect of the gamma ray strength function on the cross section calculations has been studied. A satisfactorily reproduction of the available experimental data of photonuclear cross section at the energy region below 20 MeV could be achieved. The photon flux was monitored by measuring the photons yield from seven well known (γ, n) reactions from the threshold energy of each reaction up to the end-point energy of the photon beam used. An integrated cross-section 87 ± 14 mb is calculated for the photonuclear reaction 162Er (γ, n) at the energy 9.2-14 MeV. The effective cross section estimated using the TALYS code range between 89 and 96 mb depending on the γ-strength function used. To validate the method for the estimation of the average cross-section data of 162Er (γ, n) reaction, the same procedure has been performed to calculate the average cross-section data of 197Au (γ, n) and 55Mn (γ, n) reactions. In this case, the photons yield from the rest well known (γ, n) reactions was used in order to monitoring the photon flux. The results for 162Er (γ, n), 197Au (γ, n) and 55Mn (γ, n) are found to be in good agreement with the theoretical values obtained by TALYS 1.6. So, the present indirect process could be a valuable tool to estimate the effective cross section of (γ, n) reaction for various isotopes using bremsstrahlung beams.
A Preliminary Calculation of 235U (n,2n) 234U Cross Sections
Energy Technology Data Exchange (ETDEWEB)
Chen, H.; Ross, M.A.; Reffo, G.; White, R.M.; Younes, W.
1999-11-23
Preliminary calculations of the total two-neutron emission cross section, {sup 235}U(n,2n) {sup 234}U and the partial two-neutron emission cross sections, {sup 235}U(n, 2n{gamma}) {sup 234}U, are presented. The {sup 235}U(n, 2n{gamma}) {sup 234}U cross sections describe the process of {gamma}-decays in the residual nucleus following the two-neutron emission and were calculated for several {gamma}-transitions between states of the ground-state band of the {sup 234}U nucleus. All three reaction mechanisms, namely, direct, pre-equilibrium and compound, were included. In addition, fission competition as well as {gamma}-cascade were considered in the compound component of the cross section calculations. A comparison with the relevant experimental data obtained from the GEANIE detector at the LANSCE/WNR facility in Los Alamos was also carried out.
Directory of Open Access Journals (Sweden)
Sandeep Kumar Mishra
2017-03-01
Full Text Available The combined utility of many one and two dimensional NMR methodologies and DFT-based theoretical calculations have been exploited to detect the intramolecular hydrogen bond (HB in number of different organic fluorine-containing derivatives of molecules, viz. benzanilides, hydrazides, imides, benzamides, and diphenyloxamides. The existence of two and three centered hydrogen bonds has been convincingly established in the investigated molecules. The NMR spectral parameters, viz., coupling mediated through hydrogen bond, one-bond NH scalar couplings, physical parameter dependent variation of chemical shifts of NH protons have paved the way for understanding the presence of hydrogen bond involving organic fluorine in all the investigated molecules. The experimental NMR findings are further corroborated by DFT-based theoretical calculations including NCI, QTAIM, MD simulations and NBO analysis. The monitoring of H/D exchange with NMR spectroscopy established the effect of intramolecular HB and the influence of electronegativity of various substituents on the chemical kinetics in the number of organic building blocks. The utility of DQ-SQ technique in determining the information about HB in various fluorine substituted molecules has been convincingly established.
Directory of Open Access Journals (Sweden)
István Bors
2015-09-01
Full Text Available Maize (Zea mays L. is often contaminated with Fusarium verticillioides. This harmful fungus produces fumonisins as secondary metabolites. These fumonisins can appear both free and hidden form in planta. The hidden form is usually bound covalently to cereal starch. From the hidden fumonisins, during enzymatic degradation, glycosides are formed, and the fumonisin is further decomposed during a de-esterification step. In this short communication some preliminary DFT calculated structural results which could be useful in the future to help to understand the van der Waals force controlled molecular interactions between these kinds of mycotoxin molecules and enzymes are demonstrated.
Morales, Giovanni; Martínez, Ramiro
2009-07-30
This research's main goals were to analyze ketene dimers' relative stability and expand group additivity value (GAV) methodology for estimating the thermochemical properties of high-weight ketene polymers (up to tetramers). The CBS-Q multilevel procedure and statistical thermodynamics were used for calculating the thermochemical properties of 20 cyclic structures, such as diketenes, cyclobutane-1,3-diones, cyclobut-2-enones and pyran-4-ones, as well as 57 acyclic base compounds organized into five groups. According to theoretical heat of formation predictions, diketene was found to be thermodynamically favored over cyclobutane-1,3-dione and its enol-tautomeric form (3-hydroxycyclobut-2-enone). This result did not agree with old combustion experiments. 3-Hydroxycyclobut-2-enone was found to be the least stable dimer and its reported experimental detection in solution may have been due to solvent effects. Substituted diketenes had lower stability than substituted cyclobutane-1,3-diones with an increased number of methyl substituents, suggesting that cyclobutane-1,3-dione type dimers are the major products because of thermodynamic control of alkylketene dimerization. Missing GAVs for the ketene dimers and related structures were calculated through linear regression on the 57 acyclic base compounds. Corrections for non next neighbor interactions (such as gauche, eclipses, and internal hydrogen bond) were needed for obtaining a highly accurate and precise regression model. To the best of our knowledge, the hydrogen bond correction for GAV methodology is the first reported in the literature; this correction was correlated to MP2/6-31Gdagger and HF/6-31Gdagger derived geometries to facilitate its application. GAVs assessed by the linear regression model were able to reproduce acyclic compounds' theoretical thermochemical properties and experimental heat of formation for acetylacetone. Ring formation and substituent position corrections were calculated by consecutively
A theoretical model for calculation of the detective quantum efficiency in granular scintillators
Energy Technology Data Exchange (ETDEWEB)
Cavouras, D. E-mail: cavouras@hol.gr; Kandarakis, I.; Tsoukos, S.; Kateris, A.; Nomicos, C.D.; Panayiotakis, G.S
2001-11-01
A theoretical model has been developed for calculating the detective quantum efficiency (DQE) of scintillators, by taking into account the internal structure of granular scintillators often used in medical imaging detectors. Scintillators were considered to consist of N elementary thin layers containing spherical scintillating grains of equal size. Grains were assumed to be regularly distributed within each thin layer, the thickness of the latter being equal to the grain diameter. Values of the X-ray absorption and X-ray attenuation coefficients, of the intrinsic X-ray to light conversion efficiency and of the optical scattering and absorption coefficients were used as input data to the model. Optical scattering and optical absorption coefficients were determined by fitting the model to experimental luminescence data. The model was employed to calculate the detective quantum efficiency of La{sub 2}O{sub 2}S:Tb, Y{sub 2}O{sub 2}S:Tb, Y{sub 2}O{sub 2}S:Eu, ZnSCdS:Ag, ZnSCdS:Au,Cu scintillators. Results of the calculations were found close to values published in previous studies.
Kashinski, D. O.; Nelson, R. G.; Chase, G. M.; di Nallo, O. E.; Byrd, E. F. C.
2016-05-01
We are investigating the accuracy of theoretical models used to predict the visible, ultraviolet, and infrared spectra, as well as other properties, of product materials ejected from the muzzle of currently fielded systems. Recent advances in solid propellants has made the management of muzzle signature (flash) a principle issue in weapons development across the calibers. A priori prediction of the electromagnetic spectra of formulations will allow researchers to tailor blends that yield desired signatures and determine spectrographic detection ranges. Quantum chemistry methods at various levels of sophistication have been employed to optimize molecular geometries, compute unscaled harmonic frequencies, and determine the optical spectra of specific gas-phase species. Electronic excitations are being computed using Time Dependent Density Functional Theory (TD-DFT). Calculation of approximate global harmonic frequency scaling factors for specific DFT functionals is also in progress. A full statistical analysis and reliability assessment of computational results is currently underway. Work supported by the ARL, DoD-HPCMP, and USMA.
da Silva, Julio Cesar A.; Ducati, Lucas C.; Rittner, Roberto
2012-05-01
NMR solvent effects and theoretical calculations showed muscarinic agonists present a large stability for their near synclinal conformations, indicating the presence of significant stabilization factors. Analysis of the results clearly indicated that this stability is not determined by the dihedral around the substituted C-C ethane bond, as stated by some authors, but a consequence of the geometry adopted in order to maximize N+/O interactions in this type of molecules. It can be assumed that acetylcholine and its muscarinic agonists exhibit their biologic activity when the positively charged nitrogen and the oxygen atoms are in the same side of the molecule within an interatomic distance ranging from 3.0 to 6.0 Å.
Theoretical calculation of equilibrium copper (I) isotope fractionations in ore-forming fluid
Seo, J.; Lee, I.; Lee, S.
2006-05-01
Equilibrium isotope fractionation of Cu (I) complexes in hydrothermal ore-forming fluid is calculated. Ab-initio quantum calculation of molecular structures and vibrational frequencies is conducted by Density Functional Theory (DFT) and Hartree-Fock Self Consistent Field (HF-SCF) method. Cu isotope (65Cu, 63Cu) exchange is expressed as reduced partition function ratios, 103·ln(β65-63), for liquid phase complexes (copper chlorides, copper hydrosulfides), and vapor phase complexes (hydrated copper chloride). Isodensity Polarizable Continuum Model (IPCM) is applied to the liquid complexes, whereas the vapor complexes are calculated in vacuo. Large fractionation (more than 2‰ at 25°C) is predicted between coexisting phases without changing oxidation state. CuCl(H2O)2 (vapor phase) is enriched in 65Cu better than any other studied complexes, whereas [CuCl3]2- (liquid phase) is mostly depleted. Heavy copper isotope is favor to partition into vapor phase complexes than coexisting liquid phase complexes. In the sea-floor hydrothermal system, after separation of phases into vapor and brine, vapor phase (CuCl(H2O)2) and chlorine-rich brine ([CuCl3]2-) will show +0.418‰ and -0.688‰ deviation from [CuCl2]1- at 150°C, respectively. However, most of the dominant copper-bearing species in hydrothermal condition, [CuCl2]1- and [Cu(HS)2]1-, fractionate at almost the same degree. Possible ranges of copper isotope ratio, δ65Cu, can be constrained from the calculated equilibrium isotope fractionation. Changes of oxidation state in low-temperature (e.g. supergene formation) have been thought to trigger most copper isotope fractionations, so far. However, measurable Cu isotope fractionation (1.106‰ at 150°C and 0.615‰ at 300°C) in hydrothermal ore-forming fluid is predicted within +1 valence state by theoretical study. Molecular structures and vibrational frequencies are compared with measured data. However, there is no experimental or theoretical work of some molecules
Energy Technology Data Exchange (ETDEWEB)
Wu, Yanlin [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Shi, Jin; Chen, Hongche [Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433 (China); Zhao, Jianfu [State Key Laboratory of Pollution Control and Resources Reuse, College of Environmental Science and Engineering, Tongji University, Shanghai 200092 (China); Dong, Wenbo, E-mail: wbdong@fudan.edu.cn [Shanghai Key Laboratory of Atmospheric Particle Pollution and Prevention, Department of Environmental Science & Engineering, Fudan University, Shanghai 200433 (China)
2016-10-01
4-tert-butylphenol (4-t-BP), an endocrine disrupting chemical, is widely distributed in natural bodies of water but is difficult to biodegrade. In this study, we focused on the transformation of 4-t-BP in photo-initiated degradation processes. The steady-state photolysis and laser flash photolysis (LFP) experiments were conducted in order to elucidate its degradation mechanism. Identification of products was performed using the GC–MS, LC-MS and theoretical calculation techniques. The oxidation pathway of 4-t-BP by hydroxyl radical (HO·) was also studied and H{sub 2}O{sub 2} was added to produce HO·. 4-tert-butylcatechol and 4-tert-butylphenol dimer were produced in 4-t-BP direct photolysis. 4-tert-butylcatechol and hydroquinone were produced by the oxidation of HO·. But the formation mechanism of 4-tert-butylcatechol in the two processes was different. The benzene ring was fractured in 4-t-BP oxidation process and 29% of TOC was degraded after 16 h irradiation. - Highlights: • Photodegradation of 4-t-BP, an endocrine disrupting chemical, has been investigated. • 3 stable byproducts were identified from photolysis and oxidation processes. • 5 transient by-products were concluded from LFP experiments. • The theoretical calculation was performed to confirm the byproducts. • 4-t-BP was degraded with increasing efficiency: 254 nm < H{sub 2}O{sub 2}/313 nm < H{sub 2}O{sub 2}/254 nm.
Institute of Scientific and Technical Information of China (English)
MA Dong-Ping; LIU Yan-Yun; CHEN Ju-Rong
2001-01-01
On the basis of the unified calculation of the thermal shifts of R1 line, R2 line and ground-state-splitting transition probabilities of direct and Raman processes have theoretically been calculated. The thermal broadenings of R,The theoretically predicted transition probabilities are in good agreement with the experimental ones.PACS numbers: 71.70.Ch, 78.20.Nv, 63.20.Mt, 63.20.Kr
A new method of calculating the running coupling constant --- theoretical formulation ---
Bilgici, E; Itou, E; Kurachi, M; Lin, C -J D; Matsufuru, H; Ohki, H; Onogi, T; Yamazaki, T
2008-01-01
We propose a new method to compute the running coupling constant of gauge theories on the lattice. We first give the definition of the running coupling in the new scheme using the Wilson loops in a finite volume, and explain how the running of the coupling constant is extracted from the measurement of the volume dependence. The perturbative calculation of the renormalization constant to define the scheme is also given at the leading order. As a benchmark test of the new scheme we apply the method the case of the quenched QCD. We show the preliminary result from our numerical simulations which are carried out with plaquette gauge action for various lattice sizes and bare lattice couplings. With techniques to improve the statistical accuracy, we show that we can determine the non-perturbative running of the coupling constant in a wide range of the energy scale with relatively small number of gauge configurations in our scheme. We compare our lattice data of the running coupling constant with perturbative renorm...
Zhang, Huan; Bo, Tian-Li; Zheng, Xiaojing
2017-03-01
Dusty phenomena, such as wind-blown sand, dust devils, and dust storms, play key roles in Earth's climate and geological processes. Dust electrification considerably affects the lifting and transport of dust particles. However, the electrical properties of dust storms remain poorly understood. Here, we conducted multi-parameter measurements and theoretical calculations to investigate the electrical properties of dust storms and their application to dust storm prediction. The results show that the vertical electric field (E-field) decreases first, then increases, and finally decreases with the height above the ground, reversing its direction at two heights, ∼ 8- 12 and ∼ 24 m. This suggests that the charge polarity of dust particles changes from negative to positive and back to negative again as the height increases. By carefully analyzing the E-field and dust concentration data, we further found that there is a significant positive linear relationship between the measured E-field intensity and dust concentration at the given ambient conditions. In addition, measurements and calculations demonstrate that a substantial enhancement in the vertical E-field can be observed several hours before the arrival of the external-source dust storms, indicating that the E-field can be used to provide an early warning of external-source dust storms.
Xie, Min; Qi, Yajing; Hu, Yongjun
2011-04-14
2-Phenylethylamine (PEA) is the simplest aromatic amine neurotransmitter, as well as one of the most important. In this work, the conformational equilibrium and hydrogen bonding in liquid PEA were studied by means of Raman spectroscopy and theoretical calculations (DFT/MP2). By changing the orientation of the ethyl and the NH(2) group, nine possible conformers of PEA were found, including four degenerate conformers. Comparison of the experimental Raman spectra of liquid PEA and the calculated Raman spectra of the five typical conformers in selected regions (550-800 and 1250-1500 cm(-1)) revealed that the five conformers can coexist in conformational equilibrium in the liquid. The NH(2) stretching mode of the liquid is red-shifted by ca. 30 cm(-1) relative to that of an isolated PEA molecule (measured previously), implying that intermolecular N-H···N hydrogen bonds play an important role in liquid PEA. The relative intensity of the Raman band at 762 cm(-1) was found to increase with increasing temperature, indicating that the anti conformer might be favorable in liquid PEA at room temperature. The blue shift of the band for the bonded N-H stretch with increasing temperature also provides evidence of the existence of intermolecular N-H···N hydrogen bonds.
Energy Technology Data Exchange (ETDEWEB)
Duan, Yuhua
2012-11-02
Since current technologies for capturing CO{sub 2} to fight global climate change are still too energy intensive, there is a critical need for development of new materials that can capture CO{sub 2} reversibly with acceptable energy costs. Accordingly, solid sorbents have been proposed to be used for CO{sub 2} capture applications through a reversible chemical transformation. By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO{sub 2} sorbent candidates from the vast array of possible solid materials has been proposed and validated. The calculated thermodynamic properties of different classes of solid materials versus temperature and pressure changes were further used to evaluate the equilibrium properties for the CO{sub 2} adsorption/desorption cycles. According to the requirements imposed by the pre- and post- combustion technologies and based on our calculated thermodynamic properties for the CO{sub 2} capture reactions by the solids of interest, we were able to screen only those solid materials for which lower capture energy costs are expected at the desired pressure and temperature conditions. Only those selected CO{sub 2} sorbent candidates were further considered for experimental validations. The ab initio thermodynamic technique has the advantage of identifying thermodynamic properties of CO{sub 2} capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. Such methodology not only can be used to search for good candidates from existing database of solid materials, but also can provide some guidelines for synthesis new materials. In this presentation, we first introduce our screening methodology and the results on a testing set of solids with known thermodynamic properties to validate our methodology. Then, by applying our computational method
Yalçin, C.
2017-02-01
The theoretical cross section calculations for the astrophysical p process are very crucial due to the most of the related reactions are technically very difficult to measure at the laboratory. On the other hand, the theoretical cross sections are not in agreement with the experimental results, especially for the (α,γ) reactions. One of the main reason of the difference between theoretical and experimental cross section is description of the α+nucleus optical model potential. In order to understand current situation and improvement of the theoretical calculations, the 112Sn(α,γ)116Te reaction were investigated for different global optical model potentials at the astrophysically interested energies. Astrophysical S factors were also calculated and compared with experimental data available at EXFOR database.
Habegger, Maria L; Motta, Philip J; Huber, Daniel R; Dean, Mason N
2012-12-01
Evaluations of bite force, either measured directly or calculated theoretically, have been used to investigate the maximum feeding performance of a wide variety of vertebrates. However, bite force studies of fishes have focused primarily on small species due to the intractable nature of large apex predators. More massive muscles can generate higher forces and many of these fishes attain immense sizes; it is unclear how much of their biting performance is driven purely by dramatic ontogenetic increases in body size versus size-specific selection for enhanced feeding performance. In this study, we investigated biting performance and feeding biomechanics of immature and mature individuals from an ontogenetic series of an apex predator, the bull shark, Carcharhinus leucas (73-285cm total length). Theoretical bite force ranged from 36 to 2128N at the most anterior bite point, and 170 to 5914N at the most posterior bite point over the ontogenetic series. Scaling patterns differed among the two age groups investigated; immature bull shark bite force scaled with positive allometry, whereas adult bite force scaled isometrically. When the bite force of C. leucas was compared to those of 12 other cartilaginous fishes, bull sharks presented the highest mass-specific bite force, greater than that of the white shark or the great hammerhead shark. A phylogenetic independent contrast analysis of anatomical and dietary variables as determinants of bite force in these 13 species indicated that the evolution of large adult bite forces in cartilaginous fishes is linked predominantly to the evolution of large body size. Multiple regressions based on mass-specific standardized contrasts suggest that the evolution of high bite forces in Chondrichthyes is further correlated with hypertrophication of the jaw adductors, increased leverage for anterior biting, and widening of the head. Lastly, we discuss the ecological significance of positive allometry in bite force as a possible
Theoretical Calculations of Thermal Shifts of Ground-State Zero-Field-Splitting for Ruby
Institute of Scientific and Technical Information of China (English)
MA Dong-Ping; CHEN Ju-Rong; MA Ning
2001-01-01
By taking into account all the irreducible representations and their components in the electron-phonon interaction (EPI) as well as all the levels and the admixtures of wavefunctions within d3 electronic configuration, the thermal shifts (TS) of the ground-state zero-field-splitting (GSZFS) due to EPI for ruby have microscopic-theoretically been calculated; the contribution to TS of GSZFS from thermal expansion has also been calculated. The results are in very good agreement with experiments. It is found that the contributions from the first-order perturbation of the second-order term in EPI Hamiltonian are dominant in the Raman term and optical-branch term for TS of GSZFS; the different between the TS due to EPI oft3 2 4A2 ± 1/2e2 (G2) level and the TS due to EPI oft32 4A2 ± 3/2e2 (Gl) level gives riseto the TS due to EPI of GSZFS, which is very small in comparison with the TS due to EPI of G2 or G1 level. Among various terms in TS of GSZFS, Raman term is the largest one and the signs of the Raman term and optical-branch term are opposite to the sign of the thermal-expansion term; the optical-branch term plays an important role in TS of GSZFS and increases rapidly with temperature; all various contributions to TS of GSZFS have to be taken into account, since the subtle balance among them determines the total result. The comparison between the features of TS of GSZFS and those of TS of R1 and R2 lines has been made. For TS of GSZFS, the contribution from thermal expansion is especially important; the neighbor-level term is insignificant.``
Energy Technology Data Exchange (ETDEWEB)
Pinto, Rui M., E-mail: ruipinto@fct.unl.pt [CFA, Centro de Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal); Dias, Antonio A.; Costa, Maria L. [CFA, Centro de Fisica Atomica, Departamento de Fisica, Faculdade de Ciencias e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica (Portugal)
2011-03-18
Graphical abstract: Gas-phase UV photoelectron spectrum of the thermal decomposition of 5-aminotetrazole (5ATZ), obtained at 245 {sup o}C, and mechanism underlying the thermal dissociation of 2H-5ATZ. Research highlights: {yields} Electronic structure of 5ATZ studied by photoelectron spectroscopy. {yields} Gas-phase 5-ATZ exists mainly as the 2H-tautomer. {yields} Thermal decomposition of 5ATZ gives N{sub 2}, NH{sub 2}CN, HN{sub 3} and HCN, at 245 {sup o}C. {yields} HCN can be originated from a carbene intermediate. - Abstract: The electronic properties and thermal decomposition of 5-aminotetrazole (5ATZ) are investigated using UV photoelectron spectroscopy (UVPES) and theoretical calculations. Simulated spectra of both 1H- and 2H-5ATZ, based on electron propagator methods, are produced in order to study the relative gas-phase tautomer population. The thermal decomposition results are rationalized in terms of intrinsic reaction coordinate (IRC) calculations. 5ATZ yields a HOMO ionization energy of 9.44 {+-} 0.04 eV and the gas-phase 5ATZ assumes mainly the 2H-form. The thermal decomposition of 5ATZ leads to the formation of N{sub 2}, HN{sub 3} and NH{sub 2}CN as the primary products, and HCN from the decomposition of a intermediate CH{sub 3}N{sub 3} compound. The reaction barriers for the formation of HN{sub 3} and N{sub 2} from 2H-5ATZ are predicted to be {approx}228 and {approx}150 kJ/mol, at the G2(MP2) level, respectively. The formation of HCN and HNNH from the thermal decomposition of a CH{sub 3}N{sub 3} carbene intermediate is also investigated.
Theoretical modeling of zircon's crystal morphology according to data of atomistic calculations
Gromalova, Natalia; Nikishaeva, Nadezhda; Eremin, Nikolay
2017-04-01
Zircon is an essential mineral that is used in the U-Pb dating. Moreover, zircon is highly resistant to radioactive exposure. It is of great interest in solving both fundamental and applied problems associated with the isolation of high-level radioactive waste. There is significant progress in forecasting of the most energetically favorable crystal structures at the present time. Unfortunately, the theoretical forecast of crystal morphology at high technological level is under-explored nowadays, though the estimation of crystal equilibrium habit is extremely important in studying the physical and chemical properties of new materials. For the first time, the thesis about relation of the equilibrium shape of a crystal with its crystal structure was put forward in the works by O.Brave. According to it, the idealized habit is determined in the simplest case by a correspondence with the reticular densities Rhkl of individual faces. This approach, along with all subsequent corrections, does not take into account the nature of atoms and the specific features of the chemical bond in crystals. The atomistic calculations of crystal surfaces are commonly performed using the energetic characteristics of faces, namely, the surface energy (Esurf), which is a measure of the thermodynamic stability of the crystal face. The stable crystal faces are characterized by small positive values of Esurf. As we know from our previous research (Gromalova et al.,2015) one of the constitutive factors affecting the value of the surface energy in calculations is a choice of potentials model. In this regard, we studied several sets of parameters of atomistic interatomic potentials optimized previously. As the first test model («Zircon 1») were used sets of interatomic potentials of interaction Zr-O, Si-O and O-O in the form of Buckingham potentials. To improve playback properties of zircon additionally used Morse potential for a couple of Zr-Si, as well as the three-particle angular harmonic
Energy Technology Data Exchange (ETDEWEB)
Tsukamoto, T.; Sagawa, N. [The Institute of Energy Economics, Tokyo (Japan)
1996-02-01
In order to optimize introduction of wide area power transmission access according to the amended Electric Power Business Law, discussions were given on a theoretical approach to calculation of access fee to transmission lines. The amended law is intended not to limit new comers in power generation area to operations in the supply areas for general electric power business operators, but to form power wholesale markets in wider range. Since a power wholesale market is structured via one transmission network, the access conditions for transmission lines largely govern the economic reasonability for new market comers. Too high access fee prevents high-efficiency power generation units from entering a market, thus not resulting in reduction in energy fees. Conversely, if the fee is too low, harmful effects will result in the system operation, such as entry of low-efficiency generation units. What maximizes economic gains and gives incentives to the system participants would be an operation by using a marginal expense approach, but a number of problems also exists. The overall expense distribution method is simple and easy to operate, but contains economic problems related to technical problems, fairness, and efficiency in the system operation. 5 refs., 5 figs., 1 tab.
Theoretical study of atomic oxygen on gold surface by Hückel theory and DFT calculations.
Sun, Keju; Kohyama, Masanori; Tanaka, Shingo; Takeda, Seiji
2012-09-27
It is fundamental to understand the behavior of atomic oxygen on gold surfaces so as to elucidate the mechanism of nano gold catalysts for low-temperature CO oxidation reactions since the atomic oxygen on gold system is an important intermediate involved in both the processes of O(2) dissociation and CO oxidation. We performed theoretical analysis of atomic oxygen adsorption on gold by using Hückel theory. It is found that formation of linear O-Au-O structure on Au surfaces greatly stabilizes the atomic oxygen adsorption due to stronger bond energy and bond order, which is confirmed subsequently by density functional theory (DFT) calculations. The linear O-Au-O structure may explain the surprising first order kinetics behavior of O(2) desorption from gold surfaces. This view of the linear O-Au-O structure as the natural adsorption status is quite different from the conventional view, which may lead to new understanding toward the reaction mechanism of low-temperature CO oxidation reaction on nano gold catalysts.
Poulain-Paul, Agnieszka; Nassour, Ayoub; Jelsch, Christian; Guillot, Benoit; Kubicki, Maciej; Lecomte, Claude
2012-11-01
Three models of charge-density distribution - Hansen-Coppens multipolar, virtual atom and kappa - of different complexities, different numbers of refined parameters, and with variable levels of restraints, were tested against theoretical and high-resolution X-ray diffraction structure factors for 2-methyl-4-nitro-1-phenyl-1H-imidazole-5-carbonitrile. The influence of the model, refinement strategy, multipole level and treatment of the H atoms on the dipole moment was investigated. The dipole moment turned out to be very sensitive to the refinement strategy. Also, small changes in H-atom treatment can greatly influence the calculated magnitude and orientation of the dipole moment. The best results were obtained when H atoms were kept in positions determined by neutron diffraction and anisotropic displacement parameters (obtained by SHADE, in this case) were used. Also, constraints on kappa values of H atoms were found to be superior to the free refinement of these parameters. It is also shown that the over-parametrization of the multipolar model, although possibly leading to better residuals, in general gives worse dipole moments.
García-Granados, Andrés; López, Pilar E; Melguizo, Enrique; Moliz, Juan N; Parra, Andrés; Simeó, Yolanda; Dobado, José A
2003-06-13
Several triterpenic derivatives, with the A-ring functionalized, were semisynthesized from oleanolic and maslinic acids. The reactivities of sulfites, sulfate, and epoxides in these triterpene compounds were investigated under different reaction conditions. Moreover, contracted A-ring triterpenes (five-membered rings) were obtained, by different treatments of the sulfate 7. From the epoxide 8, deoxygenated and halohydrin derivatives were semisynthesized with several nucleophiles. Ozonolysis and Beckmann reactions were used to yield 4-aza compounds, from five-membered ring olanediene triterpenes. The X-ray structure of sulfate 7 is given and compared with density functional theory geometries. Theoretical (13)C and (1)H chemical shifts (gauge-invariant atomic orbital method at the B3LYP/6-31G*//B3LYP/6-31G* level) and (3)J(H,H) coupling constants were calculated for compounds 5-9 and 34-36, identifying the (R)- or (S)-sulfur and alpha- or beta-epoxide configurations together with 4-aza or 3-aza structures.
Takeshima, Tsuguhide; Takeuchi, Hiroshi; Egawa, Toru; Konaka, Shigehiro
2005-01-01
The molecular structure of arecoline (methyl 1,2,5,6-tetrahydro-1-methylnicotinate, ? has been determined by gas electron diffraction. Diffraction patterns were taken at about 370 K. Structural constraints for the data analysis were obtained from MP2/6-31G** calculations. Vibrational mean amplitudes and shrinkage corrections were calculated from the force constants obtained from the gas-phase vibrational frequencies and the B3LYP/6-31G** calculations. The electron diffraction data were well reproduced by assuming the mixture of four conformers. The determined structural parameters ( rg (Å) and ∠ (°)) for the main conformer with 3 σ in parentheses are as follows: =1.456(4); rg(N-C methyl)=1.451 (d.p.); rg(C dbnd6 C)=1.339(9); =1.512(3); rg(O-C methyl)=1.434(5); rg(C(O)-O)=1.355 (d.p.); rg(C dbnd6 O)=1.209(4); the out-of-plane angle of the methyl group=50.3(23); ∠C ringN ringC ring=112.8(30); ∠N ringC ringC ring(H 2)=110.5(16); =118.4(5); ∠C dbnd6 CC(O)=116.8(7); ∠CC dbnd6 O=127.6(9); ∠CC-O=109.8(8), where the angle brackets denote averaged values and d.p. denotes dependent parameters. Fixing the abundances of the minor conformers, Ax-s- cis and Ax-s- trans, at the theoretical values (13% in total), those of the Eq-s- cis and Eq-s- trans conformers were determined to be 46(16) and 41(16)%, respectively. Here Ax and Eq denote the axial and equatorial directions of the N-CH 3 bond and s- cis and s- trans show the orientation of the methoxycarbonyl group expressed by the configuration of the C dbnd6 O and C dbnd6 C bonds. The N⋯O carbonyl distances of the Eq-s- cis and Ax-s- cis conformers are 4.832(13) and 4.874(16) Å, respectively. They are close to the N⋯N distance of the most abundant conformer of nicotine, 4.885(6) Å, suggesting that the Eq-s- cis and Ax-s- cis conformers have nicotinic activity.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
In this paper, primary manufacturing and assembling errors of three-ring gear reducer (TRGR) are analyzed. TRGR is a new transmission type whose eccentric phase difference between middle ring plate and side ring plates is 120°. Its mass of middle ring plate is equal to that of side ring plate or 180°, and its mass of middle ring plate is twice of that of side ring plate, which affects load distribution between ring plates. The primary manufacturing and assembling errors include eccentric error of eccentric sheath Em, internal gear plate Er and output external gear Eic. A new theoretical method is presented in this paper, which converts load on ring plates into the dedendum bending stress of ring plate to calculate load distribution coefficient ( LDC ), by means of gap elenent method (GEM), one of finite element method (FEM). The theoretical calculation and experimental study, which measures ring plate dedendum bending stress by means of sticking strain gauges on the dedendum of middle ring plate internal gear and side ring plate internal gears, are presented. The theoretical calculation and comparison with experiment result of LDC are implemented on two kinds of three-ring gear reducers whose eccentric phase difference between eccentric sheaths is 120° and 180° respectively. The research indicates that the result of theoretical calculation is consistent with that of experimental study. That is to say, the theoretical calculation method is feasible.
A selection method for the calculation of preliminary risk-based remediation goals
Energy Technology Data Exchange (ETDEWEB)
Mahoney, L.A.; Batey, J.C.; Pintenich, J.L. [Eckenfelder Inc., Nashville, TN (United States)
1995-12-31
In the process of deriving acceptable concentrations of chemical constituents (or preliminary risk-based remediation goals, PRGs) for hazardous and other waste sites based on the site risk assessment results, it may be necessary or desirable to select a subset of constituents to focus the remainder of the site activities including the feasibility study and possibly, remedial design and verification sampling. Use of a focused set of action or clean-up goals offers the benefits of targeting those site areas where efforts should be concentrated, and reducing the cost and complexity of clean-up and verification sampling. Although the federal Superfund risk assessment guidance provides methods by which to calculate PRGs, no information is given on how to select which chemicals PRGs should be generated for. A method for this selection is presented which establishes: the media of interest; the populations for which PRGs should be generated; the relevant exposure route(s) for a given population to be used in calculating PRGs; and the individual constituents for which PRGs should be estimated. To illustrate this selection process, remedial investigation (RI) data and a baseline risk assessment for a hazardous waste site in Mississippi were used. The media of interest were identified as surface water and sediment from a creek that is adjacent to the site, on-site surface water, and groundwater from the uppermost aquifer. Of the 45 constituents detected in site-related waters, this selection process resulted in 16 for which PRGs were calculated, which served to focus the subsequent feasibility study efforts.
Interaction of FeO(-) with water: anion photoelectron spectroscopy and theoretical calculations.
Zhao, Li-Juan; Xu, Xi-Ling; Xu, Hong-Guang; Feng, Gang; Zheng, Wei-Jun
2017-08-09
The interactions of FeO(-) with water molecules were studied by using photoelectron spectroscopy and density functional theoretical calculations. It is found that a dihydroxyl species, Fe(OH)2(-/0), can be formed when FeO(-/0) interacts with the first water molecule. The complexes formed via the interactions between FeO(-/0) and n water molecules can be viewed as Fe(OH)2(H2O)n-1(-/0), in which (n - 1)H2O molecules interact with a Fe(OH)2 core. For Fe(OH)2(-/0) and Fe(OH)2(H2O)(-), the Fe(OH)2 unit has two conformers with the two OH groups oriented differently. The vertical detachment energies (VDEs) of FeO2H2(H2O)n-1(-) (n = 1-4) are measured to be 1.25 ± 0.04, 1.66 ± 0.04, 2.06 ± 0.04, and 2.37 ± 0.04 eV, respectively, by experiment. It is also worth mentioning that in the FeO2H2(H2O)(-) anion the water molecule interacts with the Fe(OH)2 core by forming a hydrogen bond with one of the OH groups, while in neutral FeO2H2(H2O), the water molecule interacts with the Fe atom of the Fe(OH)2 core via its O atom.
Energy Technology Data Exchange (ETDEWEB)
Manfrini, Rozangela Magalhaes; Teixeira, Flavia Rodrigues; Pilo-Veloso, Dorila; Alcantara, Antonio Flavio de Carvalho, E-mail: aalcantara@zeus.qui.ufmg.br [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Inst. de Ciencias Exatas. Dept. de Quimica; Nelson, David Lee [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Fac. de Farmacia. Dept. de Quimica; Siqueira, Ezequias Pessoa de [Centro de Pesquisas Rene Rachou (FIOCRUZ), Belo Horizonte, MG (Brazil)
2012-07-01
The stability of N-propylbutanimine (1) was investigated under different experimental conditions. The acid-catalyzed self-condensation that produced the E-enimine (4) and Z-inimine (5) was studied by experimental analyses and theoretical calculations. Since the calculations for the energy of 5 indicated that it had a lower energy than 4, yet 4 was the principal product, the self-condensation of 1 must be kinetically controlled. (author)
Takeshima, Tsuguhide; Takeuchi, Hiroshi; Egawa, Toru; Konaka, Shigehiro
2007-09-01
The molecular structure of cotinine (( S)-1-methyl-5-(3-pyridinyl)-2-pyrrolidinone), the major metabolite of nicotine, has been determined at about 182 °C by gas electron diffraction combined with MP2 and DFT calculations. The diffraction data are consistent with the existence of the (ax, sc), (ax, ap), (eq, sp) and (eq, ap) conformers, where ax and eq indicate the configuration of the pyrrolidinone ring by means of the position (axial and equatorial) of the pyridine ring, and sc, sp and ap distinguish the isomers arising from the internal rotation around the bond connecting the two rings. The (CH 3)NCCC(N) dihedral angles, ϕ, of the (ax, sc) and (eq, sp) conformers were determined independently to be 158(12)° and 129(13)°, respectively, where the numbers in parentheses are three times the standard errors, 3 σ. According to the MP2 calculations, the corresponding dihedral angles for the (ax, ap) and (eq, ap) conformers were assumed to differ by 180° from their syn counterparts. The ratios x(ax, sc)/ x(ax, ap) and x(eq, sp)/ x(eq, ap) were taken from the theoretically estimated free energy differences, Δ G, where x is the abundance of the conformer. The resultant abundances of (ax, sc), (ax, ap), (eq, sp) and (eq, ap) conformers are 34(6)%, 21% (d.p.), 28% (d.p.), and 17% (d.p.), respectively, where d.p. represents dependent parameters. The determined structural parameters ( rg (Å) and ∠ α (°)) of the most abundant conformer, (ax, sc), are as follows: r(N sbnd C) pyrrol = 1.463(5); r(N sbnd C methyl) = 1.457(←); r(N sbnd C( dbnd O)) = 1.384(12); r(C dbnd O) = 1.219(5); = 1.541(3); r(C pyrrolsbnd C pyrid) = 1.521(←); = 1.396(2); = 1.343(←); ∠(CNC) pyrrol = 113.9(11); ∠CCC pyrrol(-C pyrid) = 103.6(←); ∠NCO = 124.1(13); ∠NC pyrrolC pyrid = 113.1(12); ∠C pyrrolC pyrrolC pyrid = 113.3(←); ∠(CNC) pyrid = 117.1(2); = 124.4(←); ∠C methylNC( dbnd O) = ∠C methylNC(-C pyrid) = 122.8(d.p.); ∠NC( dbnd O)C = 107.1(d.p.); ∠NC pyrrol
THE ACQM THEORETICAL CALCULATION OF LOW—LYING EXCITED STATES FOR HeH
Institute of Scientific and Technical Information of China (English)
Q.Q.GOU; Z.Y.Huang; 等
1990-01-01
The Low-lying excited states of HeH have been calculated by arrangement channel quantum mechanics(ACQM),The calculated potential curves,equilibrium geometry,Rc.dissociation energy Dc.harmonic vibration frequency ω0 and quadratic force coustant F2 are comparable with Ci calculations.
Energy Technology Data Exchange (ETDEWEB)
Jannik, Tim [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Stagich, Brooke [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)
2015-08-28
The U.S. Environmental Protection Agency (EPA) requested an external, independent verification study of their updated “Preliminary Remediation Goals for Radionuclides” (PRG) electronic calculator. The calculator provides PRGs for radionuclides that are used as a screening tool at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) and Resource Conservation and Recovery Act (RCRA) sites. These risk-based PRGs establish concentration limits under specific exposure scenarios. The purpose of this verification study is to determine that the calculator has no inherit numerical problems with obtaining solutions as well as to ensure that the equations are programmed correctly. There are 167 equations used in the calculator. To verify the calculator, all equations for each of seven receptor types (resident, construction worker, outdoor and indoor worker, recreator, farmer, and composite worker) were hand calculated using the default parameters. The same four radionuclides (Am-241, Co-60, H-3, and Pu-238) were used for each calculation for consistency throughout.
Spruck, K; Krantz, C; Novotný, O; Becker, A; Bernhardt, D; Grieser, M; Hahn, M; Repnow, R; Savin, D W; Wolf, A; Müller, A; Schippers, S
2014-01-01
We present new experimentally measured and theoretically calculated rate coefficients for the electron-ion recombination of W$^{18+}$([Kr] $4d^{10}$ $4f^{10}$) forming W$^{17+}$. At low electron-ion collision energies, the merged-beam rate coefficient is dominated by strong, mutually overlapping, recombination resonances. In the temperature range where the fractional abundance of W$^{18+}$ is expected to peak in a fusion plasma, the experimentally derived Maxwellian recombination rate coefficient is 5 to 10 times larger than that which is currently recommended for plasma modeling. The complexity of the atomic structure of the open-$4f$-system under study makes the theoretical calculations extremely demanding. Nevertheless, the results of new Breit-Wigner partitioned dielectronic recombination calculations agree reasonably well with the experimental findings. This also gives confidence in the ability of the theory to generate sufficiently accurate atomic data for the plasma modeling of other complex ions.
Burr, D. M.; Emery, J. P.; Lorenz, R. D.
2005-01-01
The Cassini Imaging Science System (ISS) has been returning images of Titan, along with other Saturnian satellites. Images taken through the 938 nm methane window see down to Titan's surface. One of the purposes of the Cassini mission is to investigate possible fluid cycling on Titan. Lemniscate features shown recently and radar evidence of surface flow prompted us to consider theoretically the creation by methane fluid flow of streamlined forms on Titan. This follows work by other groups in theoretical consideration of fluid motion on Titan's surface.
Evarestov, RA
2015-01-01
This book deals with the theoretical and computational simulation of monoperiodic nanostructures for different classes of inorganic substances. These simulations are related to their synthesis and experimental studies. A theoretical formalism is developed to describe 1D nanostructures with symmetric shapes and morphologies. Three types of models are considered for this aim: (i) nanotubes (rolled from 2D nanolayers and described within the formalism of line symmetry groups); (ii) nanoribbons (obtained from 2D nanolayers by their cutting along the chosen direction of translation); (iii) nanowire
Cormanich, Rodrigo A; Ducati, Lucas C; Tormena, Cláudio F; Rittner, Roberto
2014-04-01
Amino acid conformational analysis in solution are scarce, since these compounds present a bipolar zwitterionic structure ((+)H3NCHRCOO(-)) in these media. Also, intramolecular hydrogen bonds have been classified as the sole interactions governing amino acid conformational behavior in the literature. In the present work we propose phenylalanine and tyrosine methyl ester conformational studies in different solvents by (1)H NMR and infrared spectroscopies and theoretical calculations. Both experimental and theoretical results are in agreement and suggest that the conformational behavior of the phenylalanine and tyrosine methyl esters are similar and are dictated by the interplay between steric and hyperconjugative interactions.
Theoretical calculations of thermophysical properties of single-wall carbon nanotube bundles
Institute of Scientific and Technical Information of China (English)
Miao Ting-Ting; Song Meng-Xuan; Ma Wei-Gang; Zhang Xing
2011-01-01
Carbon nanotube bundles are promising thermal interfacial materials due to their excellent thermal and mechanical characteristics. In this study, the phonon dispersion relations and density of states of the single-wall carbon nanotube bundles are calculated by using the force constant model. The calculation results show that the inter-tube interaction leads to a significant frequency raise of the low frequency modes. To verify the applied calculation method, the specific heat of a single single-wall carbon nanotube is calculated first based on the obtained phonon dispersion relations and the results coincide well with the experimental data. Moreover, the specific heat of the bundles is calculated and exhibits a slight reduction at low temperatures in comparison with that of the single tube. The thermal conductivity of the bundles at low temperatures is calculated by using the ballistic transport model. The calculation results indicate that the inter-tube interaction, i.e. van der Waals interaction, hinders heat transfer and cannot be neglected at extremely low temperatures. For (5, 5) bundles, the relative difference of the thermal conductivity caused by ignoring inter-tube effect reaches the maximum value of 26% around 17 K, which indicates the significant inter-tube interaction effect on the thermal conductivity at low temperatures.
Theoretical Calculation for the Dip Feature in Tunnelling Experiment on Bi2212
Institute of Scientific and Technical Information of China (English)
谢刚; 韩汝珊
2001-01-01
We generalize a model, which was presented by Norman [Phys. Rev. Lett. 79 (1997) 3506], to calculate the Bi2Sr2CaCu2Os+δ (Bi2212) single-electron tunnelling conductance. In our calculation result, the dip feature appears which has been widely observed in tunnelling experiments. It is found that this dip feature in tunnelling experiments and the dip/hump feature in angle-resolved photoemission experiments have a common physics. Moreover, it is shown from our numerical calculation method that if the spectral function A(κ, ω) is known, the tunnelling conductance can be obtained.
A Preliminary Theoretical Analysis of a Research Experience for Undergraduates Community Model
Castillo-Garsow, Carlos; Castillo-Chavez, Carlos; Woodley, Sherry
2013-01-01
The Mathematical and Theoretical Biology Institute (MTBI) is a successful summer research experience for undergraduates, with a strong record of mentoring Ph.D. graduates, particularly, underrepresented minority students. However, the MTBI program was designed for education in research, not for research in education, and the mechanisms of the…
Kılınç, F.; Karpuz, N.; ćetin, B.
2017-02-01
In medical physics, radionuclides are needed to diagnose functional disorders of organs and to diagnose and treat many diseases. Nuclear reactions are significant for the productions of radionuclides. It is important to analyze the cross sections for much different energy. In this study, reactional cross sections calculations on 13N, 18F radioisotopes are with TALYS 1.6 nuclear reaction simulation code. Cross sections calculated and experimental data taken from EXFOR library were compared
Vinodkumar, Minaxi; Joshipura, K. N.; Limbachiya, Chetan; Mason, Nigel
2006-08-01
In this paper we report total cross sections (TCS), QT , total elastic cross sections, Qel , and total ionization cross section, Qion for electron impact on water, formaldehyde, formic acid, and the formyl radical from circa 15eVto2KeV . The results are compared where possible, with previous theoretical and experimental results and, in general, are found to be in good agreement. The total and elastic cross sections for HCHO, HCOOH, and CHO radical are reported.
Vinodkumar, M.; Joshipura, K. N.; Limbachiya, C.; Mason, Nigel
2006-01-01
In this paper we report total cross sections TCS, QT, total elastic cross sections, Qel, and total ionization cross section, Qion for electron impact on water, formaldehyde, formic acid, and the formyl radical from circa 15 eV to 2 KeV. The results are compared where possible, with previous theoretical and experimental results and, in general, are found to be in good agreement. The total and elastic cross sections for HCHO, HCOOH, and CHO radical are reported.
Shujun Yu; Xiangxue Wang; Rui Zhang; Tongtong Yang; Yuejie Ai; Tao Wen; Wei Huang; Tasawar Hayat; Ahmed Alsaedi; Xiangke Wang
2017-01-01
Although graphene oxide (GO) has been used in multidisciplinary areas due to its excellent physicochemical properties, its environmental behavior and fate are still largely unclear. In this study, batch experiments, spectroscopy analysis and theoretical calculations were addressed to promote a more comprehensive understanding toward the coagulation behavior of GO onto TiO2 under various environmental conditions (pH, co-existing ions, temperature, etc.). The results indicated that neutral pH w...
Automated Routines for Calculating Whole-Stream Metabolism: Theoretical Background and User's Guide
Bales, Jerad D.; Nardi, Mark R.
2007-01-01
In order to standardize methods and facilitate rapid calculation and archival of stream-metabolism variables, the Stream Metabolism Program was developed to calculate gross primary production, net ecosystem production, respiration, and selected other variables from continuous measurements of dissolved-oxygen concentration, water temperature, and other user-supplied information. Methods for calculating metabolism from continuous measurements of dissolved-oxygen concentration and water temperature are fairly well known, but a standard set of procedures and computation software for all aspects of the calculations were not available previously. The Stream Metabolism Program addresses this deficiency with a stand-alone executable computer program written in Visual Basic.NET?, which runs in the Microsoft Windows? environment. All equations and assumptions used in the development of the software are documented in this report. Detailed guidance on application of the software is presented, along with a summary of the data required to use the software. Data from either a single station or paired (upstream, downstream) stations can be used with the software to calculate metabolism variables.
Theoretical calculation of the shock compression properties of liquid H2 + D2 mixtures
Institute of Scientific and Technical Information of China (English)
陈其峰; 蔡灵仓; 陈栋泉; 经福谦
1999-01-01
Based on liquid variational perturbation theory with quantum mechanics correction, the effective exp-6 potential is adopted to compute the shock Hugoniot of liquid H2+D2 mixtures at different molar rations. An examination of the confidence of the above computation is performed by comparing experiments and calculations, in which similar calculation procedure used for H2+D2 is adopted for H2 and D2 each, since no experimental data are available to conduct this kind of comparison. Good agreement in both comparisons is found. This fact may look as if an indirect positive verification of calculation procedure was used here at least in the pressure and temperature domain covered by the experimental data of H2 and D2 used for comparison, numerically nearly up to 20 GPa and 104 K.
Theoretical calculation of the impact work in the alloying non-quenched and tempered steel
Institute of Scientific and Technical Information of China (English)
LIU; Zhilin; LIN; Cheng
2006-01-01
Coupled with hot-continuous rolling technology and based on the calculation of the finishing rolling impact work in the non-quenched and tempered Si-Mn steel, the calculations of the finishing rolling impact work in the alloying non-quenched and tempered steel with the elements of Cr, Ni, Mo, W, Cu, V, Nb and Ti are studied with the covalent electron number nA of the strongest bond in alloying phases, the smallest electron density difference △ρ of phase interfaces, and the number of atom states σ(σ') which keep the interface electron density continuous. The calculated results show that the finishing rolling impact work of the alloying non-quenched and tempered steel intensely depends on strengthening mechanisms. The solution strengthening, interface strengthening, precipitation strengthening of pearlite, and dispersion strengthening will result in the decrease of the finishing rolling impact work; the refinement strengthening, the precipitation strengthening of V, Nb and Ti in o-Fe-C-V(Nb, Ti), and the residual austenite containing Ni on the boundary of α-Fe-C-Ni will increase the impact work; and the increments or decrements can be calculated with nA, △ρ, σ(σ') and weights of alloying elements. The calculation formulas of the finishing rolling impact work in this paper are intergraded with the suggested ones of the finishing rolling tensile strength, yield strength, and elongation of the non-quenched and tempered steel. The calculated results agree well with the measured ones.
Calculation of theoretical lubrication regimes in two-piece first metatarsophalangeal prostheses.
Joyce, T J
2008-01-01
The key joint of the forefoot during gait is the first metatarsophalangeal joint. It plays an important role in propelling the human form but can be subject to a number of diseases which can lead to its replacement with an artificial joint. Some of these designs of prosthesis employ a two-piece ball and socket arrangement and are available with a range of biomaterial couples including ceramic-on-ceramic, metal-on-metal and metal-on-polymer. Calculation of predicted lubrication regimes applicable to these implant designs was undertaken. Modelling the ball and socket implant as an equivalent ball-on-plane model and employing elastohydrodynamic theory allowed the minimum film thickness to be calculated and in turn the lambda ratio to indicate the lubrication regime. The calculations were undertaken for a 50 to 1500 N range of loading values, a 0 to 30 mm/s range of entraining velocities, and a 3 to 15 mm radius range of sizes. Calculations showed that the ceramic-on-ceramic and metal-on-metal implants could operate under fluid film lubrication, whereas the metal-on-polymer combination operated in the boundary lubrication regime. It was also recognized that manufacturing capabilities are critical to the radial clearances and values of surface roughness that can be achieved, and thus the predicted lubrication regime.
Theoretical calculation of low-lying states of NaAr and NaXe
Laskowski, B. C.; Langhoff, S. R.; Stallcop, J. R.
1981-01-01
Potential curves as well as dipole moments and linking transition moments are calculated for the ground X 2 Sigma + and low lying excited A 2 Pi, B 2 Sigma +, C 2 Sigma +, (4) 2 Sigma +, (2) 2 Pi and (1) 2 Delta states of NaAr and NaXe. Calculations are performed using a self-consistent field plus configuration-interaction procedure with the core electrons replaced by an ab initio effective core potential. The potential curves obtained are found to be considerably less repulsive than the semiempirical curves of Pascale and Vandeplanque (1974) and to agree well with existing experimental data, although the binding energies of those states having potential minima due to van der Waals interactions are underestimated. Emission bands are also calculated for the X 2 Sigma + - C 2 Sigma + excimer transitions of NaAr and NaXe using the calculated transition moments and potential curves, and shown to agree well with experiment on the short-wavelength side of the maximum.
Determination of absolute configuration (AC) is one of the most challenging features in the structure elucidation of chiral natural products, especially those with complex structures. With revolutionary advancements in the area of quantum chemical calculations of chiroptical spectroscopy over the pa...
DEFF Research Database (Denmark)
Ruud, K.; Helgaker, T.; Jørgensen, Poul
1994-01-01
We report a systematic investigation of the magnetizability of a series of small molecules. The use of London atomic orbitals ensures gauge invariance and a fast basis set convergence. Good agreement is obtained with experimental magnetizabilities, both isotropic and anisotropic. The calculations...
Theoretical calculation of the finishing rolling elongation in non-quenched and tempered Si-Mn steel
Institute of Scientific and Technical Information of China (English)
LIU Zhilin; LIN Cheng
2006-01-01
The finishing rolling elongation in the non-quenched and tempered Si-Mn steel is theoretically calculated using the covalent electron number nA of the strongest bond in alloying phases and the interface electron density difference △ρ. Calculations show that the finishing rolling elongation of the non-quenched and tempered Si-Mn steel can be achieved by subtracting all the elongation decrements of solution strengthening, precipitation strengthening, and interface strengthening from the elongation of the refined α-Fe matrix. The calculated results of the finishing rolling tensile strength σb, the finishing rolling yield strength σs, and the finishing elongation δ of Q345steel and BG420CL steel agree well with the measured values.
A theoretical model for calculation of molecular stopping power. Ph.D. Thesis
Xu, Y. J.
1984-01-01
A modified local plasma model is established. The Gordon-Kim's molecular charged density model is employed to obtain a formula to evaluate the stopping power of many useful molecular systems. The stopping power of H2 and He gas was calculated for incident proton energy ranging from 100 keV to 2.5 MeV. The stopping power of O2, N2, and water vapor was also calculated for incident proton energy ranging from 40 keV. to 2.5 MeV. Good agreement with experimental data was obtained. A discussion of molecular effects leading to department from Bragg's rule is presented. The equipartition rule and the effect of nuclear momentum recoiling in stopping power are also discussed.
Theoretical Calculations of Refractive Properties for Hg3Te2Cl2 Crystals
Bokotey, O. V.
2016-05-01
This paper reviews the optical properties, such as refractive index, optical dielectric constant, and reflection coefficient of the Hg3Te2Cl2 crystals. The applications of the Hg3X2Y2 crystals as electronic, optical, and optoelectronic devices are very much determined by the nature and magnitude of these fundamental material properties. The origin of chemical bonding in the crystals is very important for definition of the physical and chemical properties. The main structural feature of the Hg3X2Y2 crystals is the presence of covalent pyramids [XHg3] and linear X-Hg-X groups. Optical properties are calculated according to the model proposed by Harrison. The refractive index in the spectral region far from the absorption edge is determined within the generalized single-oscillator model. The calculated results are found to be in good agreement with experimental data.
Huang, Jianhua
2012-07-01
There are three methods for calculating thermal insulation of clothing measured with a thermal manikin, i.e. the global method, the serial method, and the parallel method. Under the condition of homogeneous clothing insulation, these three methods yield the same insulation values. If the local heat flux is uniform over the manikin body, the global and serial methods provide the same insulation value. In most cases, the serial method gives a higher insulation value than the global method. There is a possibility that the insulation value from the serial method is lower than the value from the global method. The serial method always gives higher insulation value than the parallel method. The insulation value from the parallel method is higher or lower than the value from the global method, depending on the relationship between the heat loss distribution and the surface temperatures. Under the circumstance of uniform surface temperature distribution over the manikin body, the global and parallel methods give the same insulation value. If the constant surface temperature mode is used in the manikin test, the parallel method can be used to calculate the thermal insulation of clothing. If the constant heat flux mode is used in the manikin test, the serial method can be used to calculate the thermal insulation of clothing. The global method should be used for calculating thermal insulation of clothing for all manikin control modes, especially for thermal comfort regulation mode. The global method should be chosen by clothing manufacturers for labelling their products. The serial and parallel methods provide more information with respect to the different parts of clothing.
Ghazzali, Mohamed; Khattab, Sherine A. N.; Elnakady, Yasser A.; Al-Mekhlafi, Fahd A.; Al-Farhan, Khalid; El-Faham, Ayman
2013-08-01
A series of naphthyl and tolyl sulfonate ester were synthesized and characterized by H NMR. X-ray single crystal diffraction experiments established the molecular structure of three new sulfonate esters derivatives, and spectral data agree with these in solution. The observed hydrogen bonding is discussed on the basis of crystal structural analyses and DFT/MP2 geometry optimization quantum calculations. Antimicrobial activities were screened for selected compounds against three human cancer cell lines and Mosquito Culex pipiens larvae.
Directory of Open Access Journals (Sweden)
A. Djedouani
2015-03-01
Full Text Available The study of catecholase activity of a series of Schiff base compounds using in situ copper complexes of 4-hydroxy-6-methyl-3-(1-(phenyliminoethyl-2H-pyran-2-one derivatives has been reported. The reaction rate depends on four parameters: The nature of the substitution in para position to the benzene ring, the nature of counter anion, the concentration of ligand and the nature of solvent. The highest rate activity is given by complex resulting from one equivalent of ligand L2 and two equivalents of copper acetate in methanol, which equal to 62.25 µmol.min-1.L-1.In other part, a theoretical study of such ligands using the semi-empirical method AM1 were also investigated. A good relationship founded between the maximal reaction rate (Vmax and the HOMO energy (Pearson correlation: r=-0.794.
Theoretical calculations on structural and electronic properties of BGaAsBi alloys
Aslan, Metin; Yalcin, Battal G.; Ustundag, Mehmet; Bagci, Sadik
2015-11-01
The structural and electronic properties of cubic B x Ga1- x As1- y Bi y alloys with bismuth (Bi) concentration of 0.0625, 0.125, 0.1875 and 0.25 are studied with various boron (B) compositions by means of density functional theory (DFT) within the Wu-Cohen (WC) exchange correlation potential based on generalized gradient approximation (GGA). For all studied alloy structures, we have implemented geometric optimization before the volume optimization calculations. The obtained equilibrium lattice constants and band gap of studied quaternary alloys are investigated for the first time in literature. While the lattice constant behavior changes linearly with boron concentration, increasing small amount of bismuth concentration alter the lattice constant nonlinearly. The present calculation shows that the band gap decreases with increasing bismuth concentration and direct band gap semiconductor alloy became an indirect band gap with increasing boron concentration. From the band offset calculation we have shown that increasing B and Bi concentration in host GaAs reduced the valance band offset in a heterostructure formed by GaAs and studied alloys.
Directory of Open Access Journals (Sweden)
Joan Breiner
2007-01-01
Full Text Available Edaphic, foliar, and hydrologic forest nutrient status indicators from 15 mixed conifer forest stands in the Sierra Nevada, San Gabriel Mountains, and San Bernardino National Forest were used to estimate empirical or theoretical critical loads (CL for nitrogen (N as a nutrient. Soil acidification response to N deposition was also evaluated. Robust empirical relationships were found relating N deposition to plant N uptake (N in foliage, N fertility (litter C/N ratio, and soil acidification. However, no consistent empirical CL were obtained when the thresholds for parameters indicative of N excess from other types of ecosystems were used. Similarly, the highest theoretical CL for nutrient N calculated using the simple mass balance steady state model (estimates ranging from 1.4–8.8 kg N/ha/year was approximately two times lower than the empirical observations. Further research is needed to derive the thresholds for indicators associated with the impairment of these mixed conifer forests exposed to chronic N deposition within a Mediterranean climate. Further development or parameterization of models for the calculation of theoretical critical loads suitable for these ecosystems will also be an important aspect of future critical loads research.
Directory of Open Access Journals (Sweden)
Marjan Rafiee
2015-09-01
Full Text Available Tyrosinase is a multifunctional copper-containing enzyme. It can catalyze two distinct reactions of melanin synthesis and benzaldehyde derivatives, which are potential tyrosinase inhibitors. To find the relationships between charge distributions of benzaldehyde and their pharmaceutical behavior, the present study aimed at investigating nuclear quadrupole coupling constants of quadrupolare nuclei in the functional benzaldehyde group and calculating some its derivatives. In addition, the differences between the electronic structures of various derivatives of this depigmenting drug were examined. All ab initio calculations were carried out using Gaussian 03. The results predicted benzaldehyde derivatives to be bicentral inhibitors; nevertheless, the oxygen or hydrogen contents of the aldehyde group were not found to be the only active sites. Furthermore with the presence of the aldehyde group, the terminal methoxy group in C4 was found to contribute to tyrosinase inhibitory activities. In addition, an oxygen atom with high charge density in the side chain was found to play an important role in its inhibitory effect.
DFT-based Theoretical Calculation of Nb- and W-doped Anatase TiO2
Suenaga, Takahiro; Kamisaka, Hideyuki; Nakamura, Hisao; Yamashita, Koichi
2010-03-01
The structure and electronic states in the Nb-doped TiO2 (TNO) and W-doped TiO2 (TWO) in anatase phase were investigated from the first-principle using DFT-based band structure method. In addition to the cases where the dopant substituting a Ti atom, cells containing a dopant (MTi; M = Nb, W) and an oxygen vacancy (VO) were calculated in order to clarify the role of the oxygen vacancy in the system. Furthermore, cells containing two dopants and an oxygen vacancy (2MTi--VO), and cells with a dopant and two oxygen vacancies (MTi--2VO) were calculated. Energetically stable structures were found among the sampled 2WTi--VO and WTi--2VO cells, while the corresponding structures in TNO did not show any significant energy stabilization. Impurity states were found in the stable 2WTi--VO and WTi--2VO structures, and an approach of the two WTi atoms was observed in the former. The present results rationalize the lower electronic conductivity of TWO than that of TNO, and suggest possible formation of complex structures consisting of the WTi dopants and the oxygen vacancies.
Rafiee, Marjan; Javaheri, Masoumeh
2015-01-01
Tyrosinase is a multifunctional copper-containing enzyme. It can catalyze two distinct reactions of melanin synthesis and benzaldehyde derivatives, which are potential tyrosinase inhibitors. To find the relationships between charge distributions of benzaldehyde and their pharmaceutical behavior, the present study aimed at investigating nuclear quadrupole coupling constants of quadrupolare nuclei in the functional benzaldehyde group and calculating some its derivatives. In addition, the differences between the electronic structures of various derivatives of this depigmenting drug were examined. All ab initio calculations were carried out using Gaussian 03. The results predicted benzaldehyde derivatives to be bicentral inhibitors; nevertheless, the oxygen or hydrogen contents of the aldehyde group were not found to be the only active sites. Furthermore with the presence of the aldehyde group, the terminal methoxy group in C4 was found to contribute to tyrosinase inhibitory activities. In addition, an oxygen atom with high charge density in the side chain was found to play an important role in its inhibitory effect. PMID:27844007
Molecular Structure, Theoretical Calculation and Thermal Behavior of DAG(NTO)
Institute of Scientific and Technical Information of China (English)
CHANG Chun-Ran; XU Kang-Zhen; HUANG Jie; LI Meng; SONG Ji-Rong; MA Hai-Xi; ZHAO Feng-Qi
2008-01-01
A new compound,(NH2NH)2CNH+2C2N4O3Hˉ[DAG(NTO)],was prepared by mixing the NaNTO·H2O aqueous solution and diaminogannidine hydrochloride aqueous solution.Single crystals suitable for X-ray measurement were obtained by recrystaUization from water at room temperature.The crystal belongs to triclinic,space group P-1 with crystal parameters of a=0.6732(3)nm,b=0.6745(3)nm,c=0.9840(4)nm,a=88.309(7)°,β=77.255(6)°,y=86.520(7)°,V=4.349(3)nm3,Z=2,μ=0.144mm-1,F(000)=228,and Dc=1.674g/cm3.The theoretical investigation on DAG(NTO) as a structural unit was carried out by B3LYP,MP2 and HF methods with 6-31+G(d)basis set.The apparent activation energy and pre-exponential constant of the exothermic decomposition reaction of DAG(NTO)are 112.15 KJ·mol-1 and 109.603 s-1,respectively.The critical temperature of thermal explosion is 208.6℃.
Synthesis, Crystal Structure, Theoretical Calculation and Thermal Behavior of DNAZ·NTO
Institute of Scientific and Technical Information of China (English)
LI, Zhaona; MA, Haixia; YAN, Biao; GUAN, Yulei; SONG, Jirong
2009-01-01
DNAZ·NTO was prepared by mixing 3,3-dinitroazetidine (DNAZ) and 3-nitro-1,2,4-triazol-5-one (NTO) in ethanol solution. Single crystals suitable for X-ray measurement were obtained, which belong to monoclinic, space group P2_1/n with unit cell parameters of a=1.4970(4) nm, b=0.6325(2) nm, c=2.2347(7) nm, β=96.55(1)°,V=2.1022(11) nm~3, D_c=1.752 g·cm~(-3), F(000)=1136 and Z=8. Based on the analysis of the molecule structure,the theoretical investigation of the title compound was carried out at B3LYP/6-311 + +G~(**) levels, and the natural atomic charge and natural bond orbital analysis were performed. The interaction between the cation and anion was also discussed. The thermal behavior of DNAZ·NTO was carried out by DSC and TG/DTG techniques. The apparent activation energy (E_a) and pre-exponential constant (A) of the main exothermic decomposition reaction were obtained.
Synthesis, Structure and Theoretical Calculation of Imidazolium 3,5-Dinitrobenzoate
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The title adduct imidazolium 3,5-dinitrobenzoate has been synthesized in aqueous solution and characterized by elemental analyses, IR spectrum and X-ray crystallography. The title compound belongs to monoclinic, space group P21/n with a = 7.5540(9), b = 21.333(2), c =7.7823(9) (A), β = 102.741(2)°, C10H8N4O6, Mr = 280.20, V = 1223.3(2) (A)3, Z = 4, Dc = 1.521 g/cm3,F(000) = 576,μ = 0.129 mm-1, the final R = 0.0433 and wR = 0.1092 for 2001 observed reflections with I ＞ 2σ(1). The structural analysis indicates the component ions are linked by N-H…O hydrogen bonds into an infinite one-dimensional C22 (8) chain parallel to the [1 0 -1] direction. Moreover, the theoretical investigations of the title compound with HF/6-31G(d) method were performed, and its stability, frontier molecular orbital composition and Mulliken charge distribution were also discussed.
The three-fold theoretical basis of the Gravity Probe B gyro precession calculation
Adler, Ronald J
2014-01-01
The Gravity Probe B (GP-B) experiment is complete and the results are in agreement with the predictions of general relativity (GR) for both the geodetic precession, 6.6 arcsec/yr to about 0.3%, and the Lense-Thirring precession, 39 marcsec to about 19%. This note is concerned with the theoretical basis for the predictions. The predictions depend on three elements of gravity theory, firstly that macroscopic gravity is described by a metric theory such as general relativity, secondly that the Lense-Thirring metric provides an approximate description of the gravitational field of the spinning earth, and thirdly that the spin axis of a gyroscope is parallel displaced in spacetime, which gives its equation of motion. We look at each of these three elements to show how each is solidly based on previous experiments and well-tested theory. The agreement of GP-B with theory strengthens our belief that all three elements are correct and increases our confidence in applying GR to astrophysical phenomena. Conversely, if ...
Theoretical calculation on a compound formed by methyl alcohol and simmondsin
Directory of Open Access Journals (Sweden)
İzzet KARA
2016-12-01
Full Text Available Etheric oil results from the esterification reactions of oil acids with alcohols. In these reactions, one molecule water (H2O is composed of H× protons from oil acids and OH- groups which separated from alcohol. Etheric oil is commonly used in food industry, perfume industry and medicine. From this perspective, we need to know physical properties of etheric oil as well as chemical properties. In this study, the highest occupied molecular orbital (HOMO energies, the lowest unoccupied molecular orbital (LUMO energies, the electronic properties (total energy, electronegativity, chemical hardness and softness, NBO analysis and thermodynamic parameters of a compound formed by methyl alcohol and simmondsin have been performed by using Gaussian 09W program. The structural and spectroscopic data of the molecule in the ground state have been calculated by using density functional method (DFT/B3LYP with the 6-31++G(d,p basis set.
Energy Technology Data Exchange (ETDEWEB)
Nascimento, Josenaide P. do; Santos, Lourivaldo S.; Carmo, Maria Carolina L. do; Brasil, Davi S.B.; Alves, Claudio N., E-mail: nahum@ufpa.b [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Ciencias Exatas e Naturais; Santos, Regina Helena A.; Tozzo, Erica; Ferreira, Janaina G. [Universidade de Sao Paulo (IQSC/USP), Sao Carlos, SP (Brazil). Inst. de Quimica
2010-07-01
The synthesis and X-ray crystal diffraction structure of two analogues of neolignans, 2-(4-chlorophenyl)-1-phenylethanone (20) and 2-[(4-chlorophenyl)thio]-1-(3,4-dimethoxyphenyl) propan-1-one (12) is described. The compound 12 presents activity against intracellular Leishmania donovani and Leishmania amazonensis amastigotes that cause cutaneous and visceral leishmaniasis. In addition, the density functional theory (DFT) with the B3LYP hybrid functional was employed to calculate a set of molecular descriptors for nineteen synthetic analogues of neolignans with antileishmanial activities. Afterwards, the stepwise discriminant analysis was performed to investigate possible relationship between the molecular descriptors and biological activities. Through this analysis the compounds were classified into two groups active and inactive according to their degree of biological activities, and the more important properties were charges on some key atoms, electronic affinity and ClogP. (author)
Edwin, Bismi; Hubert Joe, I
2012-11-01
Vibrational spectral analysis and quantum chemical computations based on density functional theory have been performed on the anti-neuro-degenerative drug Orphenadrine hydrochloride. The geometry, intermolecular hydrogen bond, and harmonic vibrational frequencies of the title molecule have been investigated with the help of B3LYP method. The calculated molecular geometry has been compared with the experimental data. The various intramolecular interactions have been exposed by natural bond orbital analysis. The distribution of Mulliken atomic charges and bending of natural hybrid orbitals also reflect the presence of intramolecular hydrogen bonding. The analysis of the electron density of HOMO and LUMO gives an idea of the delocalization and low value of energy gap indicates electron transport in the molecule and thereby bioactivity. Effective docking of the drug molecule with NMDA receptor subunit 3A also enhances its bioactive nature. Copyright © 2012 Elsevier B.V. All rights reserved.
Jin, R. Y.; Sun, X. H.; Liu, Y. F.; Long, W.; Chen, B.; Shen, S. Q.; Ma, H. X.
2016-01-01
Series of isoxazole derivatives were synthesized by substituted chalcones and 2-chloro-6-fluorobenzene formaldehyde oxime with 1,3-dipolar cycloaddition. The target compounds were determined by melting point, IR, 1H NMR, elemental analyses and HRMS. The crystal structure of compound 3a was detected by X-ray diffraction and it crystallizes in the triclinic space group p2(1)/c with z = 4. The molecular geometry of compound 3a was optimized using density functional theory (DFT/B3LYP) method with the 6-31G+(d,p) basis set in the ground state. From the optimized geometry of the molecule, FT-IR, FT-Raman, HOMO-LUMO and natural bond orbital (NBO) were calculated at B3LYP/6-31G+(d,p) level. Finally, the antifungal activity of the synthetic compounds were evaluated against Pythium solani, Gibberella nicotiancola, Fusarium oxysporium f.sp. niveum and Gibberella saubinetii.
Theoretical Investigations of Si-Ge Alloys in P42/ncm Phase: First-Principles Calculations
Ma, Zhenyang; Liu, Xuhong; Yu, Xinhai; Shi, Chunlei; Yan, Fang
2017-01-01
The structural, mechanical, anisotropic, electronic and thermal properties of Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase are investigated in this work. The calculations have been performed with an ultra-soft pseudopotential by using the generalized gradient approximation and local density approximation in the framework of density functional theory. The achieved results for the lattice constants and band gaps of P42/ncm-Si and P42/ncm-Ge in this research have good accordance with other results. The calculated elastic constants and elastic moduli of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase are better than that of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/mnm phase. The Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase exhibit varying degrees of mechanical anisotropic properties in Poisson’s ratio, shear modulus, Young’s modulus, and universal anisotropic index. The band structures of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase show that they are all indirect band gap semiconductors with band gap of 1.46 eV, 1.25 eV, 1.36 eV and 1.00 eV, respectively. In addition, we also found that the minimum thermal conductivity κmin of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase exhibit different degrees of anisotropic properties in (001), (010), (100) and (01¯0) planes. PMID:28772964
Theoretical Investigations of Si-Ge Alloys in P42/ncm Phase: First-Principles Calculations
Directory of Open Access Journals (Sweden)
Zhenyang Ma
2017-05-01
Full Text Available The structural, mechanical, anisotropic, electronic and thermal properties of Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase are investigated in this work. The calculations have been performed with an ultra-soft pseudopotential by using the generalized gradient approximation and local density approximation in the framework of density functional theory. The achieved results for the lattice constants and band gaps of P42/ncm-Si and P42/ncm-Ge in this research have good accordance with other results. The calculated elastic constants and elastic moduli of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase are better than that of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/mnm phase. The Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase exhibit varying degrees of mechanical anisotropic properties in Poisson’s ratio, shear modulus, Young’s modulus, and universal anisotropic index. The band structures of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase show that they are all indirect band gap semiconductors with band gap of 1.46 eV, 1.25 eV, 1.36 eV and 1.00 eV, respectively. In addition, we also found that the minimum thermal conductivity κmin of the Si, Si0.667Ge0.333, Si0.333Ge0.667 and Ge in P42/ncm phase exhibit different degrees of anisotropic properties in (001, (010, (100 and (01¯0 planes.
Field theoretic calculation of energy cascade rates in non-helical magnetohydrodynamic turbulence
Indian Academy of Sciences (India)
Mahendra K Verma
2003-09-01
Energy cascade rates and Kolmogorov’s constant for non-helical steady magnetohydrodynamic turbulence have been calculated by solving the ﬂux equations to the ﬁrst order in perturbation. For zero cross helicity and space dimension = 3, magnetic energy cascades from large length-scales to small length-scales (forward cascade). In addition, there are energy ﬂuxes from large-scale magnetic ﬁeld to small-scale velocity ﬁeld, large-scale velocity ﬁeld to small-scale magnetic ﬁeld, and large-scale velocity ﬁeld to large-scale magnetic ﬁeld. Kolmogorov’s constant for magnetohydrodynamics is approximately equal to that for ﬂuid turbulence (≈ 1.6) for Alfvén ratio 0.5 ≤ A ≤ ∞. For higher space-dimensions, the energy ﬂuxes are qualitatively similar, and Kolmogorov’s constant varies as 1/3. For the normalized cross helicity c → 1, the cascade rates are proportional to (1-c)/(1+c), and the Kolmogorov’s constants vary signiﬁcantly with c.
Novotný, O; Bernhardt, D; Grieser, M; Hahn, M; Krantz, C; Lestinsky, M; Müller, A; Repnow, R; Schippers, S; Wolf, A; Savin, D W
2012-01-01
We have measured electron-ion recombination for Fe XII forming Fe XI using a merged beams configuration at the heavy-ion storage ring TSR located at the Max Planck Institute for Nuclear Physics in Heidelberg, Germany. The measured merged beams recombination rate coefficient (MBRRC) for collision energies from 0 to 1500 eV is presented. This work uses a new method for determining the absolute MBRRC based on a comparison of the ion beam decay rate with and without the electron beam on. For energies below 75 eV, the spectrum is dominated by dielectronic recombination (DR) resonances associated with 3s-3p and 3p-3d core excitations. At higher energies we observe contributions from 3-N' and 2-N' core excitations DR. We compare our experimental results to state-of-the-art multi-configuration Breit-Pauli (MCBP) calculations and find significant differences, both in resonance energies and strengths. We have extracted the DR contributions from the measured MBRRC data and transformed them into a plasma recombination ra...
Field theoretic calculation of energy cascade rates in non-helical magnetohydrodynamic turbulence
Indian Academy of Sciences (India)
Mahendra K Verma
2004-06-01
Energy cascade rates and Kolmogorov’s constant for non-helical steady magnetohydrodynamic turbulence have been calculated by solving the ﬂux equations to the ﬁrst order in perturbation. For zero cross helicity and space dimension $d = 3$, magnetic energy cascades from large length-scales to small length-scales (forward cascade). In addition, there are energy ﬂuxes from large-scale magnetic ﬁeld to small-scale velocity ﬁeld, large-scale velocity ﬁeld to small-scale magnetic ﬁeld, and large-scale velocity ﬁeld to large-scale magnetic ﬁeld. Kolmogorov’s constant for magnetohydrodynamics is approximately equal to that for ﬂuid turbulence $(≈ 1.6)$ for Alfvén ratio $0.5≤ r_{A}≤ ∞$. For higher space-dimensions, the energy ﬂuxes are qualitatively similar, and Kolmogorov’s constant varies as $d^{1/3}$. For the normalized cross helicity $_{c}→ 1$, the cascade rates are proportional to $(1-_{c})/(1+_{c})$, and the Kolmogorov’s constants vary signiﬁcantly with $_{c}$.
Hamolli, L; Nucita, A A
2014-01-01
Free-floating planets are recently drawing a special interest of the scientific community. Gravitational microlensing is up to now the exclusive method for the investigation of free-floating planets, including their spatial distribution function and mass function. In this work, we examine the possibility that the future Euclid space-based observatory may allow to discover a substantial number of microlensing events caused by free-floating planets. Based on latest results about the free-floating planet mass function in the mass range $[10^{-5}, 10^{-2}]M_{\\odot}$, we calculate the optical depth towards the Galactic bulge as well as the expected microlensing rate and find that Euclid may be able to detect hundreds to thousands of these events per month. Making use of a synthetic population, we also investigate the possibility of detecting parallax effect in simulated microlensing events due to free-floating planets and find a significant efficiency for the parallax detection that turns out to be around 30%.
Potentiometric studies and theoretical calculations of Some azo rhodanines and their metal complexes
Directory of Open Access Journals (Sweden)
K. A. Abu-Melha
2015-12-01
Full Text Available A series of 3-phenylazo-2-thioxo-4-thiazolidinone derivatives (H2L1 and H2L2 have been prepared and characterized by elemental analysis. The optimized bond lengths, bond angles and the calculated quantum chemical parameters for the ligands (H2L1 and H2L2 were investigated. Dissociation constants of (H2L1 and H2L2 and their metal-ligand stability constants of their complexes with (Cd2+, Fe2+, Fe3+, UO22+ and Zr4+ metal ions have been determined potentiometrically in 0.1M KCl and 40 % (by volume DMF-water mixture. The stability constants of the formed binary complexes were found to be Fe2+< Cd2+< Fe3+< UO22+< Zr4+. The effect of the substituents on the dissociation and stability constants was examined on the basis of the electron repelling property. The thermodynamic parameters (DG, DH and DS were reported for the ligands and complexes formation reactions. The enthalpy changes for the dissociation processes and complex systems are positive. The dissociation processes are nonspontaneous and entropically unfavorable. The metal complexes have been found to be spontaneous and entropically favorable.
Adherence of Molecules to Silica Glass Surface: Experimental Results and Theoretical Calculations
Rivera, Edison; Prado, Miguel Oscar; Nuñez, Matias
The adherence of molecules to surfaces is used in a wide scope of technological applications. In this work we study the attachment of molecules onto porous silica glass surface obtained from a Vycor glass, after glass- glass phase separation and leaching of the soluble phase with water. Nitrogen adsorption at 77 K was used for the determination of the specific surface area (BET area) and pore size distribution on the leached glass. The adherence onto the glass surface, of model molecules methylene blue (MB) and eosine yellow (EY), with positive and negative electrical charges respectively, was studied. The adsorption kinetics was determined from aqueous solutions using UV-VIS spectroscopy. It was found that the silica glass surface as prepared in this work is selective for positively charged molecules at pH≈5.20, an adsorption of 1 mg MB per gram of glass was found for methylene blue, and almost null adsorption for eosine yellow. First principles calculations were performed using the Density Functional Theory in order to model the interaction between both molecules and the glass surface.
Energy Technology Data Exchange (ETDEWEB)
Al-abyad, Mogahed; Mohamed, Gehan Y. [Atomic Energy Authority, Cairo (Egypt). Experimental Nuclear Physics Dept.
2017-08-01
Neutron capture cross section (σ{sub 0}) and resonance integral (I{sub 0}) of the reaction {sup 186}W(n,γ){sup 187}W were measured experimentally using the research reactor (ETRR-2) and an Am-Be neutron source, also calculated using TALYS-1.6 code. The present results of σ{sub 0} are (39.08±2.6, 38.75±0.98 and 38.33 barn) and I{sub 0} are (418.5±74, 439.3±36 and 445.5 barn) by using the reactor, neutron source and TALYS-1.6, respectively. The present results are in acceptable agreement with most of the previous experimental and evaluated data as well as the theoretical calculations.
Theoretical investigation of lead vapor adsorption on kaolinite surfaces with DFT calculations
Energy Technology Data Exchange (ETDEWEB)
Wang, Xinye [Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096 (China); Huang, Yaji, E-mail: heyyj@seu.edu.cn [Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096 (China); Pan, Zhigang [College of Materials Science and Engineering, Nanjing Tech University, Nanjing 210009 (China); Wang, Yongxing; Liu, Changqi [Key Laboratory of Energy Thermal Conversion and Control of Ministry of Education, School of Energy and Environment, Southeast University, Nanjing 210096 (China)
2015-09-15
Highlights: • Al surface after dehydroxylation is active while Si surface is inert. • The active sites are the unsaturated Al atoms and O atoms losing H atom. • PbO is the most suitable species for adsorption. • Increasing the activities of Al atoms can enhance the performance of kaolinite. • Produce of amorphous silica is a potential path to enhance the performance of kaolinite. - Abstract: Kaolinite can be used as the in-furnace sorbent/additive to adsorb lead (Pb) vapor at high temperature. In this paper, the adsorptions of Pb atom, PbO molecule and PbCl{sub 2} molecule on kaolinie surfaces were investigated by density functional theory (DFT) calculation. Si surface is inert to Pb vapor adsorption while Al surfaces with dehydroxylation are active for the unsaturated Al atoms and the O atoms losing H atoms. The adsorption energy of PbO is much higher than that of Pb atom and PbCl{sub 2}. Considering the energy barriers, it is easy for PbO and PbCl{sub 2} to adsorb on Al surfaces but difficult to escape. The high energy barriers of de–HCl process cause the difficulties of PbCl{sub 2} to form PbO·Al{sub 2}O{sub 3}·2SiO{sub 2} with kaolinite. Considering the inertia of Si atoms and the activity of Al atoms after dehydroxylation, calcination, acid/alkali treatment and some other treatment aiming at amorphous silica producing and Al activity enhancement can be used as the modification measures to improve the performance of kaolinite as the in-furnace metal capture sorbent.
Calzado, Carmen J
2013-01-21
This paper reports a theoretical analysis of the electronic structure and magnetic properties of a tetranuclear Cu(II) complex, [Cu(4) (HL)(4)], which has a 4+2 cubane-like structure (H(3) L=N,N'-(2-hydroxypropane-1,3-diyl)bis(acetylacetoneimine)). These theoretical calculations indicate a quintet (S=2) ground state; the energy-level distribution of the magnetic states confirm Heisenberg behaviour and correspond to an S(4) spin-spin interaction model. The dominant interaction is the ferromagnetic coupling between the pseudo-dimeric units (J(1) =22.2 cm(-1)), whilst a weak and ferromagnetic interaction is found within the pseudo-dimeric units (J(2) =1.4 cm(-1)). The amplitude and sign of these interactions are consistent with the structure and arrangement of the magnetic Cu 3d orbitals; they accurately simulate the thermal dependence of magnetic susceptibility, but do not agree with the reported J values (J(1) =38.4 cm(-1), J(2) =-18.0 cm(-1)) that result from the experimental fitting. This result is not an isolated case; many other polynuclear systems, in particular 4+2 Cu(II) cubanes, have been reported in which the fitted magnetic terms are not consistent with the geometrical features of the system. In this context, theoretical evaluation can be considered as a valuable tool in the interpretation of the macroscopic behaviour, thus providing clues for a rational and directed design of new materials with specific properties.
Ellison, Peter
2012-10-01
Component design and position are major factors in achieving adequate range of motion post hip replacement. It is therefore important to understand how implant design and positioning impact the motion available before impingement. The Yoshimine-Ginbayashi equations allow the theoretical range of motion of total hip replacements to be calculated accurately and quickly. However, a significant limitation of these equations is that they can only be applied to femoral neck geometry with a circular cross section. The objective of the present study was to reformulate the equations to allow fast and accurate calculation of the range of motion for prostheses with any femoral neck geometry. Using vector analysis, formulae were derived such that the range of motion could be calculated from the cross section of the neck at the point of impingement, cup radius at the point of impingement, cup inclination angle, cup anteversion angle, neck angle of the femoral component from the transverse plane and neck anteversion. The range of motion was calculated for circular, truncated circle and free-form femoral neck geometry under a range of component positions. These values were successfully compared with those measured from analysis of solid models in three-dimensional computer-aided design software. The method of analysis presented offers a powerful new technique enabling hip prostheses to be analysed in an accurate and efficient manner, therefore facilitating optimisation of the design geometry, assessment of existing pre-clinical designs and clinical pre- or postoperative evaluation.
Shieh, Minghuey; Chu, Yen-Yi; Hsu, Miao-Hsing; Ke, Wei-Ming; Lin, Chien-Nan
2011-01-17
The trichromium-lead complex [Pb{Cr(CO)5}3](2-) (1) was isolated from the reaction of PbCl2 and Cr(CO)6 in a KOH/MeOH solution, and the new mixed chromium-iron-lead complex [Pb{Cr(CO)5}{Fe(CO)4}2](2-) (3) was synthesized from the reaction of PbCl2 and Cr(CO)6 in a KOH/MeOH solution followed by the addition of Fe(CO)5. X-ray crystallography showed that 3 consisted of a central Pb atom bound in a trigonal-planar environment to two Fe(CO)4 and one Cr(CO)5 fragments. When complex 1 reacted with 1.5 equiv of Mn(CO)5Br, the Cr(CO)4-bridged dimeric lead-chromium carbonyl complex [Pb2Br2Cr4(CO)18](2-) (4) was produced. However, a similar reaction of 3 or the isostructural triiron-lead complex [Pb{Fe(CO)4}3](2-) (2) with Mn(CO)5Br in MeCN led to the formation of the Fe3Pb2-based trigonal-bipyramidal complexes [Fe3(CO)9{PbCr(CO)5}2](2-) (6) and [Fe3(CO)9{PbFe(CO)4}2](2-) (5), respectively. On the other hand, the Ru3Pb2-based trigonal-bipyramidal complex [Ru3(CO)9{PbCr(CO)5}2](2-) (7) was obtained directly from the reaction of PbCl2, Cr(CO)6, and Ru3(CO)12 in a KOH/MeOH solution. X-ray crystallography showed that 5 and 6 each had an Fe3Pb2 trigonal-bipyramidal core geometry, with three Fe(CO)3 groups occupying the equatorial positions and two PbFe(CO)4 or PbCr(CO)5 units in the axial positions, while 7 displayed a Ru3Pb2 trigonal-bipyramidal geometry with three equatorial Ru(CO)3 groups and two axial PbCr(CO)5 units. The complexes 3-7 were characterized spectroscopically, and their nature, formation, and electrochemistry were further examined by molecular orbital calculations at the B3LYP level of density functional theory.
Directory of Open Access Journals (Sweden)
Henry Arturo Bastidas Mora
2010-05-01
Full Text Available This article presents the properties of electric power networks for use as a channel for transmitting telecommunications signals. It starts by exploring the principles and theoretical basis for calculating power lines’ critical technical parameters, referring in detail to the following primary parameters: inductance, capacitance, conductance and resistance. It then deals with e secondary para- meters (most useful from a telecommunications perspective: characteristic impedance and propagation constant (the attenuation constant being the latter’s real component. Different topologies and low- and medium-tension aerial power line structures are verified; a mathematical model is then proposed to analyse their behaviour at high frequencies, extending to most aerial electric power distribution systems in Colombia. This work includes some of the results from previous research which was known as “U- sing power line telecommunications (PLT technology for designing a solution for accessing the broadband internet in rural areas of Colombia” by the present author and the Pilot University of Colombia. The proposed mathematical model provides a tool for making theoretical calculations applicable to PLT.
Gu, Zhenyan; Lei, Wu; Shi, Wenyan; Hao, Qingli; Si, Weimeng; Xia, Xifeng; Wang, Fengxiang
2014-11-01
The interaction between 9-fluorenylmethyl chloroformate (FMOC-Cl) and Fe3+ and Cu2+ ions was investigated using fluorescence, UV/Vis absorption spectroscopies and theoretical calculation. The optical property of FMOC-Cl was studied in detail in absence and presence of various transition metal ions with particular affinity to Fe3+ and Cu2+ ions. With the fluorescence characteristic band centered at 307 and 315 nm for FMOC-Cl, the introduction of Fe3+ or Cu2+ ions leads to the fluorescence quenching of FMOC-Cl with different shift and intensities of two fluorescent bands. It allows us to differentiate between FMOC-Cl and Fe3+ and Cu2+ ions interaction behavior. The study on fluorescent kinetics confirms that the fluorescence quenching of FMOC-Cl with Fe3+ and Cu2+ ions is based on the formation of non-fluorescent material, that is, static quenching. Further analyses of bond lengths, Mulliken atomic charges and the frontier orbital compositions for FMOC-Cl and its complexes with Fe3+ and Cu2+ ions were carried out. The theoretical calculations prove the fluorescence quenching originates from the formation of coordination bonds between the oxygen atom of the carbonyl group of FMOC-Cl and Fe3+ and Cu2+ ions. The commercially available FMOC-Cl can be used as excellent fluorescent probe toward Fe3+ and Cu2+ ions with high sensitivity.
Calzado, Carmen J; Ben Amor, Nadia; Maynau, Daniel
2014-07-14
This paper reports a theoretical analysis of the electronic structure and magnetic properties of a ferromagnetic Cu(II) [3×3] grid. A two-step strategy, combining calculations on the whole grid and on binuclear fragments, has been employed to evaluate all the magnetic interactions in the grid. The calculations confirm an S = 7/2 ground state, which is in accordance with the magnetisation versus field curve and the thermal dependence of the magnetic moment data. Only the first-neighbour coupling terms present non-negligible amplitudes, all of them in agreement with the structure and arrangement of the Cu 3d magnetic orbitals. The results indicate that the dominant interaction in the system is the antiferromagnetic coupling between the ring and the central Cu sites (J3 = J4 ≈ -31 cm(-1)). In the ring two different interactions can be distinguished, J1 = 4.6 cm(-1) and J2 = -0.1 cm(-1), in contrast to the single J model employed in the magnetic data fit. The calculated J values have been used to determine the energy level distribution of the Heisenberg magnetic states. The effective magnetic moment versus temperature plot resulting from this ab initio energy profile is in good agreement with the experimental curve and the fitting obtained with the simplified spin model, despite the differences between these two spin models. This study underlines the role that the theoretical evaluations of the coupling constants can play on the rationalisation of the magnetic properties of these complex polynuclear systems.
Theoretical study of fMet-tRNA and fAla-tRNA structures by using quantum calculation
Directory of Open Access Journals (Sweden)
M. Noei
2016-11-01
Full Text Available In the prokaryotes, protein synthesis always starts with N-formylmethionine amino acid. Comparison of this amino acid with other amino acids is attempted and that is why formylmethionine is always the first amino acid to begin protein synthesis, in this paper we added a formyl group to alanine amino acid and then studied it when attached to the tRNA molecule and compared this structure with formylmethionine-tRNA structure. The quantum chemical calculations have performed using Gaussian 03 suite of programs. The fAla-tRNA and fMet-tRNA structures have fully optimized at the HF and B3LYP levels with 3–21G∗ and 6–31G∗ basis sets as well as MP2/3–21G∗ level and theoretically solvent effects on the structures were investigated. Then we studied electronic structures of the compounds using Natural Bond Orbital (NBO analysis and calculated NMR parameters at the gas-phase. Frequency analysis was also calculated at the HF and B3LYP/3-21G∗ levels in the different solvents in 298.15 K, 310.15 K temperatures and 1.00 atmosphere pressure.
Preliminary Study on the Calculation Method of “Carbon Footprint”
Institute of Scientific and Technical Information of China (English)
无
2011-01-01
At present, greenhouse effect has become a severe challenge of international society. In order to cope with this challenge, countries all over the world reached an agreement to develop low-carbon economy and create low-carbon society. As a new concept, "carbon footprint" emerged with the vigorous development of low-carbon economy, and its calculation method is related to the evaluation system of low carbon economy. In order to calculate "carbon footprint", "carbon subject" in the study was divided into ener...
Matos, Maria J.; Uriarte, Eugenio; Santana, Lourdes; Vilar, Santiago
2013-06-01
Compounds 1 (4-methyl-N-(coumarin-3-yl)benzamide) and 2 ((coumarin-3-yl)-4-methylbenzoate) were synthesized by linking the coumarin system (3-aminocoumarin or 3-hydroxycoumarin, respectively) to a p-toluoylchloride. 1H and 13C NMR and X-ray diffractometry determined the molecular structures of both derivatives. The X-ray results were compared to those obtained by conformational analysis followed by semiempirical methodologies (AM1 and PM3). The theoretical calculations yielded results reproducing the whole three-dimensional (3D) structure of both molecules in a good agreement with X-ray structural analysis. The global structures of the two compounds are very similar in the two studied environments, meaning that the structural determination in the gas phase can be extrapolated. A comparative study between compounds 1 and 2, based on the structural results, was carried out.
Buchalski, Piotr; Kamińska, Elzbieta; Piwowar, Katarzyna; Suwińska, Kinga; Jerzykiewicz, Lucjan; Rossi, Fulvio; Laschi, Franco; de Biani, Fabrizia Fabrizi; Zanello, Piero
2009-06-01
Reactions of 9-nickelafluorenyllithium with cobalt and nickel pentamethylcyclopentadienyl-acetylacetonates resulted in the formation of the novel nickelacyclic-cobaltocene 2 and nickelacyclic-nickelocene 3, respectively, in which the central metal atom is bonded to the nickelafluorenyl ring. On the basis of their redox propensity, compounds 2 and 3 were oxidized to the corresponding monocations [2](+) and [3](+). The crystal and molecular structures of both the redox couples were determined by single-crystal X-ray analysis. In spite of their structural similarity, they display a rather different electron transfer ability. To throw light on such an aspect, the pertinent redox couples have been examined by EPR spectroscopy and the nature of the frontier orbitals involved in the redox activity of the neutral precursors has been supported by extended Huckel theoretical calculations.
Duarte, S B; Guzmán, F; Di Marco, A; García, F; Rodríguez, O; Gonçalves, M
2002-01-01
Half-life values of spontaneous nuclear decay processes are presented in the framework of the effective liquid drop model (ELDM) using the combination of varying mass asymmetry shape description for the mass transfer (VMAS) and Werner-Wheeler's inertia coefficient (WW). The calculated half lives of ground-state to ground-state transitions for proton emission, alpha decay, cluster radioactivity, and cold fission processes are compared with experimental data. These comparisons show that the ELDM is a very efficient model to describe these different decay processes in a same, unified, theoretical framework. A table listing the predicted half-life values, tau sub c , is presented for all possible cases of spontaneous nuclear breakup such that -7.30 -17.0, where tau is the total half life of the parent nucleus.
Institute of Scientific and Technical Information of China (English)
LIU; Zhilin; LIN; Cheng; WANG; Ping
2006-01-01
Based on the hot-continuous rolling technology, the finishing rolling impact work αk of the non-quenched and tempered Si-Mn steel is theoretically calculated with the covalent electron number nA of the strongest bond in alloying phases, and the smallest interface electron density difference Δρ of alloying phase interface and the number of atom states σ which keep the interface electron density continuous. Calculations show that the solution strengthening, the precipitation strengthening, and the interface strengthening will result in the decrease of the finishing rolling impact work αk, and the effects of the number of atom states σ which keep the interface electron density continuous on the finishing rolling impact work αk are different. Taking the impact work and the number of atom states α0 keeping the electron density continuous of the phase interface α-Fe/α-Fe-C between α-Fe and α-Fe-C as reference values, the impact work of the interface will increase when σof some interface is larger than α0; otherwise, the impact will decrease. Therefore, the finishing rolling impact work αk can be calculated with the impact value of the refined α-Fe matrix and the influence amounts caused by the solution strengthening, the precipitation strengthening, the interface strengthening, and the number of atom states σ which keep the interface electron density continuous. The calculated results agree well with the measured ones. In this paper, the effect of S on the impact work is also discussed.
Loued, W.; Wéry, J.; Dorlando, A.; Alimi, K.
2015-02-01
In this paper, the significance of annealing, in two different atmospheres (air and vacuum), on the surface characteristics of poly (lactic acid) (PLA) films was investigated. X-ray diffraction (XRD) measurements correlated to atomic force microscopy (AFM) observations of the cast PLA films show that thermal treatment under air atmosphere is responsible for a significant increase of crystallinity with the increase of temperature. However, band gap energy of the title compound is slightly affected by annealing at different temperatures. As for the untreated PLA, the molecular geometry was optimized using density functional theory (DFT/B3LYP) method with 6-31g (d) basis set in ground state. From the optimized geometry, HOMO and LUMO energies and quantum chemical parameters were performed at B3LYP/6-31g (d). The theoretical results, applied to simulated optical spectra of the compound, were compared to the observed ones. On the basis of theoretical vibrational analyses, the thermodynamic properties were calculated at different temperatures, revealing the correlation between internal energy (U), enthalpy (H), entropy (S), Free energy (G) and temperatures.
Energy Technology Data Exchange (ETDEWEB)
Davidson, S; Followill, D; Ibbott, G [University of Texas M. D. Anderson Cancer Center, Houston, TX (United States); Cui, J; Deasy, J [Washington University, St. Louis, MO (United States)], E-mail: sedavids@mdanderson.org
2008-02-01
The Dose Planning Method (DPM) is one of several 'fast' Monte Carlo (MC) computer codes designed to produce an accurate dose calculation for advanced clinical applications. We have developed a flexible machine modeling process and validation tests for open-field and IMRT calculations. To complement the DPM code, a practical and versatile source model has been developed, whose parameters are derived from a standard set of planning system commissioning measurements. The primary photon spectrum and the spectrum resulting from the flattening filter are modeled by a Fatigue function, cut-off by a multiplying Fermi function, which effectively regularizes the difficult energy spectrum determination process. Commonly-used functions are applied to represent the off-axis softening, increasing primary fluence with increasing angle ('the horn effect'), and electron contamination. The patient dependent aspect of the MC dose calculation utilizes the multi-leaf collimator (MLC) leaf sequence file exported from the treatment planning system DICOM output, coupled with the source model, to derive the particle transport. This model has been commissioned for Varian 2100C 6 MV and 18 MV photon beams using percent depth dose, dose profiles, and output factors. A 3-D conformal plan and an IMRT plan delivered to an anthropomorphic thorax phantom were used to benchmark the model. The calculated results were compared to Pinnacle v7.6c results and measurements made using radiochromic film and thermoluminescent detectors (TLD)
Davidson, S.; Cui, J.; Followill, D.; Ibbott, G.; Deasy, J.
2008-02-01
The Dose Planning Method (DPM) is one of several 'fast' Monte Carlo (MC) computer codes designed to produce an accurate dose calculation for advanced clinical applications. We have developed a flexible machine modeling process and validation tests for open-field and IMRT calculations. To complement the DPM code, a practical and versatile source model has been developed, whose parameters are derived from a standard set of planning system commissioning measurements. The primary photon spectrum and the spectrum resulting from the flattening filter are modeled by a Fatigue function, cut-off by a multiplying Fermi function, which effectively regularizes the difficult energy spectrum determination process. Commonly-used functions are applied to represent the off-axis softening, increasing primary fluence with increasing angle ('the horn effect'), and electron contamination. The patient dependent aspect of the MC dose calculation utilizes the multi-leaf collimator (MLC) leaf sequence file exported from the treatment planning system DICOM output, coupled with the source model, to derive the particle transport. This model has been commissioned for Varian 2100C 6 MV and 18 MV photon beams using percent depth dose, dose profiles, and output factors. A 3-D conformal plan and an IMRT plan delivered to an anthropomorphic thorax phantom were used to benchmark the model. The calculated results were compared to Pinnacle v7.6c results and measurements made using radiochromic film and thermoluminescent detectors (TLD).
Preliminary Development of Thermal Power Calculation Code H-Power for a Supercritical Water Reactor
Directory of Open Access Journals (Sweden)
Fan Zhang
2014-01-01
Full Text Available SCWR (Supercritical Water Reactor is one of the promising Generation IV nuclear systems, which has higher thermal power efficiency than current pressurized water reactor. It is necessary to perform the thermal equilibrium and thermal power calculation for the conceptual design and further monitoring and calibration of the SCWR. One visual software named H-Power was developed to calculate thermal power and its uncertainty of SCWR, in which the advanced IAPWS-IF97 industrial formulation was used to calculate the thermodynamic properties of water and steam. The ISO-5167-4: 2003 standard was incorporated in the code as the basis of orifice plate to compute the flow rate. New heat balance model and uncertainty estimate have also been included in the code. In order to validate H-Power, an assessment was carried out by using data published by US and Qinshan Phase II. The results showed that H-Power was able to estimate the thermal power of SCWR.
Yu, Shujun; Wang, Xiangxue; Zhang, Rui; Yang, Tongtong; Ai, Yuejie; Wen, Tao; Huang, Wei; Hayat, Tasawar; Alsaedi, Ahmed; Wang, Xiangke
2017-01-01
Although graphene oxide (GO) has been used in multidisciplinary areas due to its excellent physicochemical properties, its environmental behavior and fate are still largely unclear. In this study, batch experiments, spectroscopy analysis and theoretical calculations were addressed to promote a more comprehensive understanding toward the coagulation behavior of GO onto TiO2 under various environmental conditions (pH, co-existing ions, temperature, etc.). The results indicated that neutral pH was beneficial to the removal of GO due to the electrostatic interaction. The presence of cations accelerated GO coagulation significantly owing to the influence of electrical double layer compression. On the contrary, the presence of anions improved the stability of GO primarily because of electrostatic repulsion and steric hindrance. Results of XRD, FTIR and XPS analysis indicated that the coagulation of GO on TiO2 was mainly dominated by electrostatic interactions and hydrogen bonds, which were further evidenced by DFT calculations. The high binding energy further indicated the stability of GO + TiO2 system, suggesting that TiO2 can be used as an effective coagulant for the efficient elimination and coagulation of GO from aqueous solutions. These findings might likely lead to a better understanding of the migration and transformation of carbon nanomaterials in the natural environment.
Park, Hanwool; Lee, Choul-Gyun
2016-11-01
Microalgae have long been considered as one of most promising feedstocks with better characteristics for biofuels production over conventional energy crops. There have been a wide range of estimations on the feasibility of microalgal biofuels based on various productivity assumptions and data from different scales. The theoretical maximum algal biofuel productivity, however, can be calculated by the amount of solar irradiance and photosynthetic efficiency (PE), assuming other conditions are within the optimal range. Using the actual surface solar irradiance data around the world and PE of algal culture systems, maximum algal biomass and biofuel productivities were calculated, and feasibility of algal biofuel were assessed with the estimation. The results revealed that biofuel production would not easily meet the economic break-even point and may not be sustainable at a large-scale with the current algal biotechnology. Substantial reductions in the production cost, improvements in lipid productivity, recycling of resources, and utilization of non-conventional resources will be necessary for feasible mass production of algal biofuel. Among the emerging technologies, cultivation of microalgae in the ocean shows great potentials to meet the resource requirements and economic feasibility in algal biofuel production by utilizing various marine resources. © 2016 The Authors. Biotechnology Journal published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Park, Hanwool
2016-01-01
Abstract Microalgae have long been considered as one of most promising feedstocks with better characteristics for biofuels production over conventional energy crops. There have been a wide range of estimations on the feasibility of microalgal biofuels based on various productivity assumptions and data from different scales. The theoretical maximum algal biofuel productivity, however, can be calculated by the amount of solar irradiance and photosynthetic efficiency (PE), assuming other conditions are within the optimal range. Using the actual surface solar irradiance data around the world and PE of algal culture systems, maximum algal biomass and biofuel productivities were calculated, and feasibility of algal biofuel were assessed with the estimation. The results revealed that biofuel production would not easily meet the economic break‐even point and may not be sustainable at a large‐scale with the current algal biotechnology. Substantial reductions in the production cost, improvements in lipid productivity, recycling of resources, and utilization of non‐conventional resources will be necessary for feasible mass production of algal biofuel. Among the emerging technologies, cultivation of microalgae in the ocean shows great potentials to meet the resource requirements and economic feasibility in algal biofuel production by utilizing various marine resources. PMID:27782372
A theoretical study of perovskite CsXCl3 (X=Pb, Cd) within first principles calculations
Ilyas, Bahaa M.; Elias, Badal H.
2017-04-01
The structural, elastic, electronic, optical acoustic and thermodynamic properties of the cubic perovskite CsPbCl3 and CsCdCl3 unit cell, were studied using an ultra-soft pseudopotential plane wave, the Trouiller-Martins-Functional was utilized to perform these calculations. The study was implemented within both the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA). the Generalized Gradient Approximation (GGA) scheme proposed by van Leeuwen-Baerends which is the same as the Perdew-Wang 92 functional have been carried out to preform our calculations. As for the Local Density Approximation (LDA) the Teter-Pade parametrization (4/93) was implemented which is the same as Perdew-Wang that in its turn reproduces the Ceperley-Alder-Functional. The computed GGA/LDA-lattice parameter for both CsCdCl3 and CsPbCl3 is in an exquisite agreement with the experimental and theoretical results. The energy band structure shows that CsCdCl3 is Γ-R indirect band gap insulator, while CsPbCl3 is an insulator with a direct band gap Γ-Γ separating the valence bands from the conduction bands, which shows metallic nature after pressure 30 GPa. A hybridization exists between Pb-p states and Cl-p states for CsPbCl3, and Cd-p states and Cs-p states for the CsCdCl3 in the valence bonding region. Optimization of both cell shape (geometry) volume were investigated as pressure of 0-20 GPa and 0-40 GPa for the CsCdCl3 and CsPbCl3 respectively. The Pressure dependence of cubic perovskite elastic constants, Young modulus, bulk and shear moduli, Lame's constants, elastic anisotropy factor, elastic wave velocities, phonon dispersion, Debye temperature and the density of states of CsXCl3 (X=Pb, Cd) were theoretically calculated and compared with the other available theoretical results. The above elastic constants reveal the fact that both compounds are stable and show nature of ductility. For the optical properties, both the static refractive index and dielectric
A theoretical study of perovskite CsXCl3 (X=Pb, Cd) within first principles calculations
Energy Technology Data Exchange (ETDEWEB)
Ilyas, Bahaa M., E-mail: bahaastring@gmail.com [Department of Physics, University Of Dohuk (Iraq); Elias, Badal H. [Laboratory of Theoretical Physics, Department of Physics, Faculty of Sciences, University of Dohuk (Iraq)
2017-04-01
The structural, elastic, electronic, optical acoustic and thermodynamic properties of the cubic perovskite CsPbCl{sub 3} and CsCdCl{sub 3} unit cell, were studied using an ultra-soft pseudopotential plane wave, the Trouiller-Martins-Functional was utilized to perform these calculations. The study was implemented within both the Local Density Approximation (LDA) and the Generalized Gradient Approximation (GGA). the Generalized Gradient Approximation (GGA) scheme proposed by van Leeuwen-Baerends which is the same as the Perdew-Wang 92 functional have been carried out to preform our calculations. As for the Local Density Approximation (LDA) the Teter-Pade parametrization (4/93) was implemented which is the same as Perdew-Wang that in its turn reproduces the Ceperley-Alder-Functional. The computed GGA/LDA-lattice parameter for both CsCdCl{sub 3} and CsPbCl{sub 3} is in an exquisite agreement with the experimental and theoretical results. The energy band structure shows that CsCdCl{sub 3} is Γ–R indirect band gap insulator, while CsPbCl{sub 3} is an insulator with a direct band gap Γ–Γ separating the valence bands from the conduction bands, which shows metallic nature after pressure 30 GPa. A hybridization exists between Pb-p states and Cl-p states for CsPbCl{sub 3}, and Cd-p states and Cs-p states for the CsCdCl{sub 3} in the valence bonding region. Optimization of both cell shape (geometry) volume were investigated as pressure of 0–20 GPa and 0–40 GPa for the CsCdCl{sub 3} and CsPbCl{sub 3} respectively. The Pressure dependence of cubic perovskite elastic constants, Young modulus, bulk and shear moduli, Lame’s constants, elastic anisotropy factor, elastic wave velocities, phonon dispersion, Debye temperature and the density of states of CsXCl{sub 3} (X=Pb, Cd) were theoretically calculated and compared with the other available theoretical results. The above elastic constants reveal the fact that both compounds are stable and show nature of ductility. For
Preliminary Calculations of Shutdown Dose Rate for the CTS Diagnostics System
DEFF Research Database (Denmark)
Klinkby, Esben Bryndt; Nonbøl, Erik; Lauritzen, Bent
2015-01-01
DTU and IST 2 are partners in the design of a collective Thomson Scattering (CTS) diagnostics for ITER through a contract with F4E. The CTS diagnostic utilizes probing radiation of ~60 GHz emitted into the plasma and, using a mirror, collects the scattered radiation by an array of receivers. Having...... a direct and unshielded view to the plasma, the first mirror will be subject to significant radiation and among the first tasks in the CTS design, is to determine whether the mirror will need active cooling. At present the CTS is in the conceptual design phase and the related neutronics calculations focus...
Preliminary Calculation of the EROI for the Production of Gas in Russia
Directory of Open Access Journals (Sweden)
Roman Nogovitsyn
2014-09-01
Full Text Available Russia is one of the world’s largest producers of energy resources. Production of energy resources in Russia is profitable, both economically and in terms of the energy produced (as measured by EROI. At the present time, Russian oil and gas companies have a policy of energy saving, and data on energy consumption is given in annual reports. Based on these data, we can make the EROI calculation. In 2013, the EROI for the production, transportation and processing of gas for Open joint stock company (OJSC “Gazprom” was 79:1; for OJSC “NOVATEK”, 76:1; for OJSC “Yakutsk Fuel and Energy Company (YATEC”, only for production, 116:1. Currently, the situation in the oil and gas industry has come to a point when there is a need for the introduction of an energy audit.
Preliminary Analysis on Distribution Calculation of Elevator%电梯配电计算初析
Institute of Scientific and Technical Information of China (English)
谢宁
2014-01-01
以电机采用蜗轮蜗杆传动方式的一般电梯为例，提出电梯配电设计的功率应以满载时电功率转换为机械功率的传动功率为依据。对配置一般起重用（绕线转子异步）电动机为动力的曳引机的电梯主回路供电，提出配电计算思路。同时论述电动机铭牌功率和按需要系数法得出的功率，都不能真实反映电梯电功率和机械功率的能量关系。%A common elevator characterized in that the motor adopts worm-gear transmission is taken as an example, based on that the power of the elevator distribution design shall be the transmission power for converting the electrical power into the mechanical power under full load, a distribution calculation idea is proposed for power supply to the main circuit of the elevator with a general crane motor (asynchronous wound-rotor) as dynamic tractor. Besides, the rated power and the power calculated by demand factor method are discussed, both of which are unable to truly reflect the energy relationship between the electrical power and the mechanical power of the elevator.
Preliminary study on CAD-based method of characteristics for neutron transport calculation
Chen, Zhen-Ping; Sun, Guang-Yao; Song, Jing; Hao, Li-Juan; Hu, Li-Qin; Wu, Yi-Can
2013-01-01
The method of characteristics (MOC) is widely used for neutron transport calculation in recent decades. However, the key problem determining whether MOC can be applied in highly heterogeneous geometry is how to combine an effective geometry modeling method with it. Most of the existing MOC codes conventionally describe the geometry model just by lines and arcs with extensive input data. Thus they have difficulty in geometry modeling and ray tracing for complicated geometries. In this study, a new method making use of a CAD-based automatic modeling tool MCAM which is a CAD/Image-based Automatic Modeling Program for Neutronics and Radiation Transport developed by FDS Team in China was introduced for geometry modeling and ray tracing of particle transport to remove those limitations. The diamond -difference scheme was applied to MOC to reduce the spatial discretization errors of the flat flux approximation. Based on MCAM and MOC, a new MOC code was developed and integrated into SuperMC system, whic h is a Super ...
Preliminary safety calculations to improve the design of Molten Salt Fast Reactor
Energy Technology Data Exchange (ETDEWEB)
Brovchenko, M.; Heuer, D.; Merle-Lucotte, E.; Allibert, M.; Capellan, N.; Ghetta, V.; Laureau, A. [LPSC, CNRS/IN2P3, Grenoble INP, 53,rue des Martyrs, 38026 Grenoble Cedex (France)
2012-07-01
Molten salt reactors are liquid fuel reactors so that they are flexible in operation but very different in the safety approach from solid fuel reactors. This study bears on the specific concept named Molten Salt Fast Reactor (MSFR). Since this new nuclear technology is in development, safety is an essential point to be considered all along the R and D studies. This paper presents the first step of the safety approach: the systematic description of the MSFR, limited here to the main systems surrounding the core. This systematic description is the basis on which we will be able to devise accidental scenarios. Thanks to the negative reactivity feedback coefficient, most accidental scenarios lead to reactor shut down. Because of the decay heat generated in the fuel salt, it must be cooled. After the description of the tools developed to calculate the residual heat, the different contributions are discussed in this study. The decay heat of fission products in the MSFR is evaluated to be low (3% of nominal power), mainly due to the reprocessing that transfers the fission products to the gas reprocessing unit. As a result, the contribution of the actinides is significant (0.5% of nominal power). The unprotected loss of heat sink transients are studied in this paper. It appears that slow transients are favorable (> 1 min) to minimize the temperature increase of the fuel salt. This work will be the basis of further safety studies as well as an essential parameter for the design of the draining system. (authors)
The complete quantum collapse scenario of 2+1 dust shell: Preliminary Calculations
Ortiz, L
2007-01-01
If we consider the gravitational collapse of a material object to a black hole, we would expect, for ranges of mass where a black hole would form, the following scenario. A large enough object would collapse classically until an event horizon forms, and to an external observer the object would be lost fom view. However, once the horizon has formed the black hole will begin to emit Hawking radiation and the hole will lose mass and the horizon will shrink. The final state of this process could be either a zero-mass "black hole" with consequent information loss, or some sort of "quantum remnant. A complete investigation of this process would require: 1) A complete and consistent theory of quantum gravity coupled to some kind of field that would provide the Hawking radiation (which could be the gravitational field itself --gravitons); 2) Some kind of definition of a "horizon" in this quantum gravity, and; 3) The calculational tools to achieve a description of the scenario. Lacking these, one may resort to toy mod...
Qu, Y. D.; Zhang, W. J.; Kong, X. Q.; Zhao, X.
2016-03-01
The heat-transfer behavior of the interface of Flyer plate (or Base Plate) has great influence on the microcosmic structures, stress distributions, and interface distortion of the welded interface of composite plates by explosive welding. In this paper, the temperature distributions in the combing zone are studied for the case of Cu/Fe composite plate jointed by explosive welding near the lower limit of explosive welding. The results show that Flyer plate (Cu plate) and Base Plate (Fe plate) firstly almost have the same melting rate in the explosive welding process. Then, the melting rate of Cu plate becomes higher than that of Fe plate. Finally, the melt thicknesses of Cu plate and Fe plate trend to be different constants, respectively. Meanwhile, the melting layer of Cu plate is thicker than that of Fe plate. The research could supply some theoretical foundations for calculating the temperature distribution and optimizing the explosive welding parameters of Cu/Fe composite plate to some extent.
Zou, Yidong; Wang, Xiangxue; Ai, Yuejie; Liu, Yunhai; Li, Jiaxing; Ji, Yongfei; Wang, Xiangke
2016-04-01
Graphene oxide (GO) has attracted considerable attention because of its remarkable enhanced adsorption and multifunctional properties. However, the toxic properties of GO nanosheets released into the environment could lead to the instability of biological system. In aqueous phase, GO may interact with fine mineral particles, such as chloridion intercalated nanocrystallined Mg/Al layered double hydroxides (LDH-Cl) and nanocrystallined Mg/Al LDHs (LDH-CO3), which are considered as coagulant molecules for the coagulation and removal of GO from aqueous solutions. Herein the coagulation of GO on LDHs were studied as a function of solution pH, ionic strength, contact time, temperature and coagulant concentration. The presence of LDH-Cl and LDH-CO3 improved the coagulation of GO in solution efficiently, which was mainly attributed to the surface oxygen-containing functional groups of LDH-Cl and LDH-CO3 occupying the binding sites of GO. The coagulation of GO by LDH-Cl and LDH-CO3 was strongly dependent on pH and ionic strength. Results of theoretical DFT calculations indicated that the coagulation of GO on LDHs was energetically favored by electrostatic interactions and hydrogen bonds, which was further evidenced by FTIR and XPS analysis. By integrating the experimental results, it was clear that LDH-Cl could be potentially used as a cost-effective coagulant for the elimination of GO from aqueous solutions, which could efficiently decrease the potential toxicity of GO in the natural environment.
Energy Technology Data Exchange (ETDEWEB)
Duarte, S.B.; Tavares, O.A.P.; Guzman, F.; Dimarco, A. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil); Garcia, F. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologicas; Rodriguez, O. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Instituto Superior de Ciencias e Tecnologia Nucleares, La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria (IRD), Rio de Janeiro, RJ (Brazil)
2002-01-01
Half-life values of spontaneous nuclear decay processes are presented in the framework of the Effective Liquid Drop Model (ELDM) using the combination of varying mass asymmetry shape description for the mass transfer with Werner-Wheeler's inertia coefficient V{sub MAS}/WW. The calculated half-lives of ground-state to ground-state transitions for the proton emission, alpha decay, cluster radioactivity, and cold fission processes are compared with experimental data. Results have shown that the ELDM is a very efficient model to describe these different decay processes in a same, unified theoretical framework. A Table listing the predicted half-life values, {tau}{sub c} is presented for all possible cases of spontaneous nuclear break-up such that -7.30 <{approx_equal} log{sub 10} {tau}{sub c} [S] <{approx_equal} 27.50 and log {sub 10}({tau}/{tau}{sub c}) > -17.0, where {tau} is the total half-life of the parent nucleus. (author)
Directory of Open Access Journals (Sweden)
Yujie Huang
2015-01-01
Full Text Available This paper theoretically investigates interactions between a template and functional monomer required for synthesizing an efficient molecularly imprinted polymer (MIP. We employed density functional theory (DFT to compute geometry, single-point energy, and binding energy (ΔE of an MIP system, where spermidine (SPD and methacrylic acid (MAA were selected as template and functional monomer, respectively. The geometry was calculated by using B3LYP method with 6-31+(d basis set. Furthermore, 6-311++(d, p basis set was used to compute the single-point energy of the above geometry. The optimized geometries at different template to functional monomer molar ratios, mode of bonding between template and functional monomer, changes in charge on natural bond orbital (NBO, and binding energy were analyzed. The simulation results show that SPD and MAA form a stable complex via hydrogen bonding. At 1 : 5 SPD to MAA ratio, the binding energy is minimum, while the amount of transferred charge between the molecules is maximum; SPD and MAA form a stable complex at 1 : 5 molar ratio through six hydrogen bonds. Optimizing structure of template-functional monomer complex, through computational modeling prior synthesis, significantly contributes towards choosing a suitable pair of template-functional monomer that yields an efficient MIP with high specificity and selectivity.
Klaassen, Joshua J; Darkhalil, Ikhlas D; Deodhar, Bhushan S; Gounev, Todor K; Gurusinghe, Ranil M; Tubergen, Michael J; Groner, Peter; Durig, James R
2013-08-01
The FT-microwave spectrum of cyclobutylcarboxylic acid chloride, c-C4H7C(O)Cl, has been recorded and 153 transitions for the (35)Cl and (37)Cl isotopologues have been assigned for the gauche-equatorial (g-Eq) conformation. The ground state rotational constants were determined for (35)Cl [(37)Cl]: A = 4349.8429(25) [4322.0555(56)] MHz, B = 1414.8032(25) [1384.5058(25)] MHz, and C = 1148.2411(25) [1126.3546(25)] MHz. From these rotational constants and ab initio predicted parameters, adjusted r0 parameters are reported with distances (Å) rCα-C = 1.491(4), rC═O = 1.193(3), rCα-Cβ = 1.553(4), rCα-Cβ' = 1.540(4), rCγ-Cβ = 1.547(4), rCγ-Cβ' = 1.546(4), rC-Cl = 1.801(3) and angles (deg) τCγCβCβ'Cα = 30.9(5). Variable temperature (-70 to -100 °C) infrared spectra (4000 to 400 cm(-1)) were recorded in liquid xenon and the g-Eq conformer was determined the most stable form, with enthalpy differences of 91 ± 9 cm(-1) (1.09 ± 0.11 kJ/mol) for the gauche-axial (g-Ax) form and 173 ± 17 cm(-1) (2.07 ± 0.20 kJ/mol) for the trans-equatorial (t-Eq) conformer. The relative amounts at ambient temperature are 54% g-Eq, 35 ± 1% g-Ax, and 12 ± 1% t-Eq forms. Vibrational assignments have been provided for the three conformers and theoretical calculations were carried out. The results are discussed and compared to corresponding properties of related molecules.
Bakker, D.J.; Vries, W. de
1996-01-01
Methodologies are described for calculating critical loads of persistent organic pollutants (POPs) for soils and surface waters. The various aspects which are discussed, are: environmental quality criteria, calculation methods, input data and the various sources of uncertainty. The calculation
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
A density functional theory (DFT)-calculation scheme for constructing the modified embedded atom method (MEAM) potentials for face-centered cubic (fcc) metals is presented. The input quantities are carefully selected and a more reliable DFT approach for surface energy determination is introduced in the parameterization scheme, enabling MEAM to precisely predict the surface and nanoscale properties of metallic materials. Molecular dynamics simulations on Pt and Au crystals show that the parameterization employed leads to significantly improved accuracy of MEAM in calculating the surface and nanoscale properties, with the results agreeing well with both DFT calculations and experimental observations. The present study implies that rational DFT parameterization of MEAM may lead to a theoretical tool to bridge the gap between nanoscale theoretical simulations and DFT calculations.
Castañeda, I. C. Henao; Jios, J. L.; Piro, O. E.; Tobón, G. E.; Della Védova, C. O.
2007-10-01
Structural and conformational properties of S-(2-methoxyphenyl) 4-nitrobenzenecarbothioate ( I), S-(2-methoxyphenyl) 4-chlorobenzenecarbothioate ( II) and S-(2-methoxyphenyl) 4-methylbenzenecarbothioate ( III) are analyzed using data of two new structures obtained from X-ray diffraction, vibrational data and theoretical calculations. According to chemical quantum calculations, the synperiplanar and +anticlinal forms were found as the first and second more stable conformations, respectively, for the title compounds. The geometric parameters and normal modes of vibration have been calculated using a density functional theory method (B3LYP) and the 6-31+G ∗∗ basis set. The calculated parameters are in good agreement with the corresponding X-ray diffraction values. The combined experimental and theoretical approach allows a consistent assignment for most of the fundamental modes.
Castro, Maria Eugenia; Percino, M Judith; Chapela, Victor M; Soriano-Moro, Guillermo; Ceron, Margarita; Melendez, Francisco J
2013-05-01
This study examined absorption properties of 2-styrylpyridine, trans-2-(m-cyanostyryl)pyridine, trans-2-[3-methyl-(m-cyanostyryl)]pyridine, and trans-4-(m-cyanostyryl)pyridine compounds based on theoretical UV/Vis spectra, with comparisons between time-dependent density functional theory (TD-DFT) using B3LYP, PBE0, and LC-ωPBE functionals. Basis sets 6-31G(d), 6-31G(d,p), 6-31+G(d,p), and 6-311+G(d,p) were tested to compare molecular orbital energy values, gap energies, and maxima absorption wavelengths. UV/Vis spectra were calculated from fully optimized geometry in B3LYP/6-311+G(d,p) in gas phase and using the IEFPCM model. B3LYP/6-311+G(d,p) provided the most stable form, a planar structure with parameters close to 2-styrylpyridine X-ray data. Isomeric structures were evaluated by full geometry optimization using the same theory level. Similar energetic values were found: ~4.5 kJ mol(-1) for 2-styrylpyridine and ~1 kJ mol(-1) for derivative compound isomers. The 2-styrylpyridine isomeric structure differed at the pyridine group N-atom position; structures considered for the other compounds had the cyano group attached to the phenyl ring m-position equivalent. The energy difference was almost negligible between m-cyano-substituted molecules, but high energy barriers existed for cyano-substituted phenyl ring torsion. TD-DFT appeared to be robust and accurate approach. The B3LYP functional with the 6-31G(d) basis set produced the most reliable λmax values, with mean errors of 0.5 and 12 nm respect to experimental values, in gas and solution, respectively. The present data describes effects on the λmax changes in the UV/Vis absorption spectra of the electron acceptor cyano substituent on the phenyl ring, the electron donor methyl substituent, and the N-atom position on the electron acceptor pyridine ring, causing slight changes respect to the 2-styrylpyridine title compound.
Directory of Open Access Journals (Sweden)
Żelazny Katarzyna
2015-01-01
Full Text Available During ship design, its service speed is one of the crucial parameters which decide on future economic effects. As sufficiently exact calculation methods applicable to preliminary design stage are lacking the so called contract speed which a ship reaches in calm water is usually applied. In the paper [11] a parametric method for calculation of total ship resistance in actual weather conditions (wind, waves, sea current, was presented. This paper presents a parametric model of ship propulsion system (screw propeller - propulsion engine as well as a calculation method, based on both models, of mean statistical value of ship service speed in seasonal weather conditions occurring on shipping lines. The method makes use of only basic design parameters and may be applied in preliminary design stage.
Directory of Open Access Journals (Sweden)
Isaev Veniamin
2016-01-01
Full Text Available Calculation of compressed footings settlement is one of the most vital tasks of soil mechanics. The calculation method of layer-by-layer addition, which recommended by current regulations and used in structural engineering practice, is most suitable for determining the settlement of foundations with an area of less than 50 m2. The authors prove that it’s possible to apply the one-dimensional problem of soils compression seal theory to the calculation of the settlement of large foundation plates. The proposed method of determining the settlement of large foundation plates makes the calculations simpler. There are examples of comparable calculations using the existing and proposed methods.
Costa, Renyer A.; Oliveira, Kelson M. T.; Costa, Emmanoel Vilaça; Pinheiro, Maria L. B.
2017-10-01
A combined experimental and theoretical DFT study of the structural, vibrational and electronic properties of strychnobrasiline and 12-hydroxy-10,11-dimethoxystrychnobrasiline is presented using the Becke three-parameter Lee-Yang-Parr function (B3LYP) and 6-311G(2d,p) basis set. The theoretical geometry optimization data were compared with the X-ray data for a similar structure in the associated literature, showing close values. The calculated HOMO-LUMO gap values showed that the presence of substituents in the benzene ring influences the quantum properties which are directly related to the reactive properties. Theoretical UV spectra agreed well with the measured experimental data, with bands assigned. In addition, Natural Bond Orbitals (NBOs), Mapped molecular electrostatic potential surface (MEPS) and NLO calculations were also performed at the same theory level. The theoretical vibrational analysis revealed several characteristic vibrations that may be used as a diagnostic tool for other strychnobrasiline type alkaloids, simplifying their identification and structural characterization. Molecular docking calculations with DNA Topoisomerase II-DNA complex showed binding free energies values of -8.0 and -9.5 kcal/mol for strychnobrasiline and 12-hydroxy-10,11-dimethoxystrychnobrasiline respectively, while for amsacrine, used for the treatment of leukemia, the binding free energy ΔG presented a value of -10.0 kcal/mol, suggesting that strychnobrasiline derivative alkaloids might exhibit an antineoplastic activity.
Li, Shenhui; Zheng, Anmin; Su, Yongchao; Fang, Hanjun; Shen, Wanling; Yu, Zhiwu; Chen, Lei; Deng, Feng
2010-04-21
Extra-framework aluminium (EFAL) species in hydrated dealuminated HY zeolite were thoroughly investigated by various two-dimensional solid-state NMR techniques as well as density functional theoretical calculations. (27)Al MQ MAS NMR experiments demonstrated that five-coordinated and four-coordinated extra-framework aluminium subsequently disappeared with the increase of water loading, and the quadrupole interaction of each aluminium species decreased gradually during the hydration process. (1)H double quantum MAS NMR revealed that the EFAL species in the hydrated zeolite consisted of three components: a hydroxyl AlOH group, and two types of water molecule (rigid and mobile water). (1)H-(27)Al LG-CP HETCOR experiments indicated that both the extra-framework and the framework Al atoms were in close proximity to the rigid water in the fully rehydrated zeolite. The experimental results were further confirmed by DFT theoretical calculations. Moreover, theoretical calculation results further demonstrated that the EFAL species in the hydrated zeolite consisted of the three components and the calculated (1)H NMR chemical shift for each component agreed well with our NMR observations. It is the rigid water that connects the extra-framework aluminium with the four-coordinated framework aluminium through strong hydrogen bonds.
Directory of Open Access Journals (Sweden)
Filip Zdraveski
2015-05-01
Full Text Available This paper explores the possibilities of the Eurocode EN 1991-1-4 to be used to predict the response of structures with installed dynamic vibration absorber or TMD.The analysis is performed in a way that Davenport model is used to conduct theoretical calculation, and then is made calculation according to Eurocode procedure 2. Finally, results from both methods are compared. Floor displacements, accelerations, aerodynamical damping of structure and compliance to serviceability criteria ISO 10137:2007 is being calculated. In the end, remarks concerning the usability of the EN standard for predicting wind response of wind susceptible structures are given on the basis of calculated results from both methods.
2007-01-01
Edaphic, foliar, and hydrologic forest nutrient status indicators from 15 mixed conifer forest stands in the Sierra Nevada, San Gabriel Mountains, and San Bernardino National Forest were used to estimate empirical or theoretical critical loads (CL) for nitrogen (N) as a nutrient. Soil acidification response to N deposition was also evaluated. Robust empirical relationships were found relating N deposition to plant N uptake (N in foliage), N fertility (litter C/N ratio), and soil acidification...
Yi, Xingwen; Xu, Bo; Zhang, Jing; Lin, Yun; Qiu, Kun
2014-12-15
Digital coherent superposition (DCS) of optical OFDM subcarrier pairs with Hermitian symmetry can reduce the inter-carrier-interference (ICI) noise resulted from phase noise. In this paper, we show two different implementations of DCS-OFDM that have the same performance in the presence of laser phase noise. We complete the theoretical calculation on ICI reduction by using the model of pure Wiener phase noise. By Taylor expansion of the ICI, we show that the ICI power is cancelled to the second order by DCS. The fourth order term is further derived out and only decided by the ratio of laser linewidth to OFDM subcarrier symbol rate, which can greatly simplify the system design. Finally, we verify our theoretical calculations in simulations and use the analytical results to predict the system performance. DCS-OFDM is expected to be beneficial to certain optical fiber transmissions.
Directory of Open Access Journals (Sweden)
Gümüs Hacer Pir
2015-06-01
Full Text Available Quantum chemical calculations have been performed to study the molecular geometry, 1H and 13C NMR chemical shifts, conformational, natural bond orbital (NBO and nonlinear optical (NLO properties of the 2-chloro-5-(2-hydroxyethyl-4- methoxy-6-methylpyrimidine molecule in the ground state using DFT and HF methods with 6-311++G(d,p basis set. The optimized geometric parameters and 1H and 13C NMR chemical shifts have been compared with the experimental values of the title molecule. The results of the calculations show excellent agreement between the experimental and calculated frequencies at B3LYP/6-311++G(d,p level. In order to provide a full understanding of the properties of the title molecule in the context of molecular orbital picture, the highest occupied molecular energy level (EHOMO, the lowest unoccupied molecular energy level (ELUMO, the energy difference (DE between EHOMO and ELUMO, electronegativity (χ, hardness (η and softness (S have been calculated using B3LYP/6-311++G(d,p and HF/6-311++G(d,p levels. The calculated HOMO and LUMO energies show that the charge transfer occurs within the title molecule.
Derkaoui, Z.; Kebbab, Z.; Miloua, R.; Benramdane, N.
2009-08-01
A new method for predicting optical characteristics of multilayer coatings based on calculated material properties is presented. This method combines the use of the full potential linear-augmented plane wave method (FP-LAPW) within the framework of the Density Functional Theory (DFT) and the optical matrix approach for modeling the multilayer assembly. The simulation process is applied to thin films of the II-VI semiconductors compounds. The optical constants of each thin film are determined by using the first principle calculations. Each layer is represented by the square Abeles matrix, including all necessary data in the calculation of the optical characteristics (as transmittance, reflectance and absorbance). The simulation of multilayer optical response includes the effect of thickness, light polarization and incident angle. The obtained results are helpful in the design of the multilayer systems with required properties.
Institute of Scientific and Technical Information of China (English)
Wu Xing-Ju; Chen Xiang-Jun; Shan Xu; Chen Li-Qing; Xu Ke-Zun
2004-01-01
The triple differential cross section for the low-energy electron impact ionization of inner-valence 3s orbital of argon has been calculated using the modified distorted wave Born approximation in coplanar symmetric energy-sharing geometry. Satisfactory agreement between theory and experiment is achieved when the polarization and post-collisional interaction (PCI) are included in the calculations. It is shown that the polarization and PCI effects play a very important role in the case of argon at low incident energies.
Wilson, Chick C.; Morrison, Carole A.
2002-08-01
Low temperature neutron diffraction and high level computational methods have been applied to investigate the short hydrogen bond in urea-phosphoric acid. It is found that isolated molecule calculations predict a `normal' O-H⋯O hydrogen bond, in strong disagreement with the very short, 3 c-4 e hydrogen bond found from the neutron diffraction. Extending these calculations into a periodic environment using plane-wave DFT methods give much improved agreement with experiment, with a much shorter, stronger hydrogen bond, and significant elongation of the O-H `covalent' bond.
Roldán, María L.; Ledesma, Ana E.; Raschi, Ana B.; Castillo, María V.; Romano, Elida; Brandán, Silvia A.
2013-06-01
A new study on the structural and vibrational properties of the aminoethylphosphonic acid was performed in aqueous solution phase by using the self-consistent reaction field (SCRF) method. We have studied and characterized it by infrared and Raman spectroscopies in solid and aqueous solution phases. The Density Functional Theory (DFT) method with Pople's basis set show that three stable zwitterions for the title molecule have been theoretically determined in aqueous solution and that probably they are present in it medium. Here, the solvent effects were studied by means of the self-consistent reaction field (SCRF) method with the polarized continuum model (PCM). The harmonic vibrational frequencies for the optimized geometries of the three zwitterions were calculated at the B3LYP/6-31G∗ level of the theory. A complete assignment of the IR and Raman spectra of the compound in aqueous solution was performed combining the DFT calculations with Pulay's Scaled Quantum Mechanics Force Field (SQMFF) methodology in order to fit the theoretical frequency values to the experimental ones. Moreover, Natural Bond Orbital (NBO) and topological properties calculations were performed to analyze the energies and geometrical parameters of its three zwitterions in aqueous medium as well as the magnitude of the intramolecular interactions. The bond orders, atomic charges, solvation energies, dipole moments, molecular electrostatic potentials and force constants parameters calculated for zwitterions in aqueous solution, may be used to gain chemical and vibrational insights into related compounds.
Theoretical calculations of high-pressure phases of NiF2: An ab initio constant-pressure study
Kürkçü, Cihan; Merdan, Ziya; Öztürk, Hülya
2016-12-01
We have studied the structural properties of the antiferromagnetic NiF2 tetragonal structure with P42/ mnm symmetry using density functional theory (DFT) under rapid hydrostatic pressure up to 400 GPa. For the exchange correlation energy we used the local density approximation (LDA) of Ceperley and Alder (CA). Two phase transformations are successfully observed through the simulations. The structures of XF2-type compounds crystallize in rutile-type structure. NiF2 undergoes phase transformations from the tetragonal rutile-type structure with space group P42/ mnm to orthorhombic CaCl2-type structure with space group Pnnm and from this orthorhombic phase to monoclinic structure with space group C2/ m at 152 GPa and 360 GPa, respectively. These phase changes are also studied by total energy and enthalpy calculations. According to these calculations, we perdict these phase transformations at about 1.85 and 30 GPa.
Synthesis, crystal structure, IR, 1H NMR and theoretical calculations of 1,2,4-triazole Schiff base
Jin, R. Y.; Sun, X. H.; Liu, Y. F.; Long, W.; Lu, W. T.; Ma, H. X.
2014-03-01
5-Propyl-4-amino-1,2,4-triazole Schiff base was characterized by FT-IR, 1H NMR and X-ray single crystal diffraction techniques. The compound crystallizes in the triclinic space group p-1 with z = 2. The molecular geometry was optimized using density functional theory (DFT/B3LYP) and hartree fock (HF) methods with the 6-311G+(d,p) and 6-311G basis set in ground state. From the optimized geometry of the molecule, vibrational frequencies, HOMO-LUMO and natural bond orbital (NBO) were calculated with B3LYP/6-311G+(d,p) level. In addition, gauge independent atomic orbital (GIAO) 1H NMR chemical shift values was calculated at B3LYP/6-311G+(d,p) and HF/6-311G+(d,p) level.
Institute of Scientific and Technical Information of China (English)
ZHANG Hai-tao; WU Di; ZHANG Li-xing
2008-01-01
The relative response factors(RRFs) for noble gas(Ng) were determined on a pulsed discharge helium photoionization detector,Using ab initio method,the atomic orbitals of noble gas were calculated and used to determine the number of ionizable electrons on the basis of the continuous emission of He2,The molar responses of noble gases is well correlated with the number of ionizable electrons.
Katsukura, Hirotaka; Miyata, Tomohiro; Tomita, Kota; Mizoguchi, Teruyasu
2017-07-01
The effect of the van der Waals (vdW) interaction on the simulation of the electron energy-loss near edge structure (ELNES) by a first-principles band-structure calculation is reported. The effect of the vdW interaction is considered by the Tkatchenko-Scheffler scheme, and the change of the spectrum profile and the energy shift are discussed. We perform calculations on systems in the solid, liquid and gaseous states. The transition energy shifts to lower energy by approximately 0.1eV in the condensed (solid and liquid) systems by introducing the vdW effect into the calculation, whereas the energy shift in the gaseous models is negligible owing to the long intermolecular distance. We reveal that the vdW interaction exhibits a larger effect on the excited state than the ground state owing to the presence of an excited electron in the unoccupied band. Moreover, the vdW effect is found to depend on the local electron density and the molecular coordination. In addition, this study suggests that the detection of the vdW interactions exhibited within materials is possible by a very stable and high resolution observation. Copyright © 2016 Elsevier B.V. All rights reserved.
Institute of Scientific and Technical Information of China (English)
YU Li-Li; SHOU Wen-De; HUI Chun
2011-01-01
A new linear phased array on a concave cylindrical transducer is designed for meeting the specific requirements of applications for interstitial thermal ablation. Using the array, a focal line can be generated rapidly and the focal position can be adjusted in the proper range without the use of complex mechanical structures. The focused acoustic Reid distributions in the axial, radial and azimuthal directions of the transducer are investigated theoretically by numerical simulation. Effects of the focal distance, steering angle, element arc-width, arc-space between adjacent elements and number of elements on the acoustic field are also thoroughly studied. Many important results are obtained.%A new linear phased array on a concave cylindrical transducer is designed for meeting the specific requirements of applications for interstitial thermal ablation.Using the array,a focal line can be generated rapidly and the focal position can be adjusted in the proper range without the use of complex mechanical structures.The focused acoustic field distributions in the axial,radial and azimuthal directions of the transducer are investigated theoretically by numerical simulation.Effects of the focai distance,steering angle,element arc-width,arc-space between adjacent elements and number of elements on the acoustic field are also thoroughly studied.Many important results are obtained.Interstitial thermal ablation is a promising technique for treating tumors that are both nonresectable and difficult to reach with extracorporeal therapy.[1,2] In this method,a small transducer is brought into contact with the targeted region and emits a highintensity acoustic wave;the interaction between the wave and the tissues causes a strong heating effect that induces the thermal coagulation and necrosis of the target.[3
Ai, Yuhui; Lange, Rebecca A
2008-03-01
A rigorous analysis of the torsional modes in both a cylindrical wave guide and the associated static viscous fluid field has been conducted from the solid and the fluid wave equations and the coupled boundary conditions. As a result, two acoustic viscometer models, along with four independent equations connecting the density and the viscosity of the fluid with the attenuation and the phase velocity of the torsional wave in the wave guide, have been developed. The analysis shows that the product of the viscosity and the density of the fluid can be measured from the end reflection coefficient of the torsional wave in the wave guide and that both the viscosity and the density can be determined simultaneously from either the phase velocity or the attenuation of the torsional wave in a single cylindrical wave guide. For the simultaneous measurements of the viscosity and the density, the independent equations have to be solved numerically, for example, using Matlab (The MathWorks, Natick, MA), given either the attenuation or the phase velocity in the wave guide that is surrounded by the fluid. To demonstrate the technical feasibility, numerical simulations have been conducted to discern viscosity, phase velocity, and density, all versus attenuation, at different frequencies, and with variable dimension of a molybdenum rod, so that both the advantages and the disadvantages of the simultaneous measurements can be explored. In the end, to test the two models, preliminary experiments on two viscous standards were conducted at 23 degrees C, and good agreements have been achieved between the viscosities measured from both models and for both standards.
Microscopic-Theoretical Calculations ofR-Line Thermal Shifts and Broadenings of MgO:V2
Institute of Scientific and Technical Information of China (English)
MA Dong-Ping; LIU Yan-Yun; MA Ning; CHEN Ju-Rong
2002-01-01
A great improvement on a previous work (Phys. Rev. B48 (1993) 14067) has been made. By taking intoaccount all the irreducible representations and their components in the electron-phonon interaction (EPI) as well as allthe levels and the admixtures of basic wavefunctions within d3 electronic configuration, the values of all the parametersin the expressions of thermal shift (TS) and thermal broadening (TB) from EPI for the ground level, R level and R lineof MgO:V2+ have microscopically been evaluated; and then, both the TS and TB of R line and various contributions tothem have uniformly been calculated. The results are in very good agreement with the experimental data. It is foundthat all the three terms of TS from EPI are red shifts; the term of the contribution to TS from thermal expansion is blueshift. The Raman term is the largest, and the other terms are also important for TS. The R-line TS of MgO:V2+ comesfrom the first-order term of EPI. The elastic Raman scattering of acoustic phonons plays a dominant role in R-line TBof MgO:V2+. For calculations of both the TS and TB, it is very important to take into account all the admixtures ofwavefunctions.
Yin, W.; Peyton, A. J.; Stefani, F.; Gerbeth, G.
2009-10-01
A completely contactless flow measurement technique based on the principle of EM induction measurements—contactless inductive flow tomography (CIFT)—has been previously reported by a team based at Forschungszentrum Dresden-Rossendorf (FZD). This technique is suited to the measurement of velocity fields in high conductivity liquids, and the possible applications range from monitoring metal casting and silicon crystal growth in industry to gaining insights into the working of the geodynamo. The forward problem, i.e. calculating the induced magnetic field from a known velocity profile, can be described as a linear relationship when the magnetic Reynolds number is small. Previously, an integral equation method was used to formulate the forward problem; however, although the sensitivity matrices were calculated, they were not explicitly expressed and computation involved the solution of an ill-conditioned system of equations using a so-called deflation method. In this paper, we present the derivation of the sensitivity matrix directly from electromagnetic field theory and the results are expressed very concisely as the cross product of two field vectors. A numerical method based on a finite difference method has also been developed to verify the formulation. It is believed that this approach provides a simple yet fast route to the forward solution of CIFT. Furthermore, a method for sensor design selection based on eigenvalue analysis is presented.
Woldegebriel, Michael
2015-11-17
In toxicology screening (forensic, food-safety), due to several analytical errors (e.g., retention time shift, lack of repeatability in m/z scans, etc.), the ability to confidently identify/confirm a compound remains a challenge. Due to these uncertainties, a probabilistic approach is currently preferred. However, if a probabilistic approach is followed, the only statistical method that is capable of estimating the probability of whether the compound of interest (COI) is present/absent in a given sample is Bayesian statistics. Bayes' theorem can combine prior information (prior probability) with data (likelihood) to give an optimal probability (posterior probability) reflecting the presence/absence of the COI. In this work, a novel method for calculating an informative prior probability for a Bayesian model in targeted toxicology screening is introduced. In contrast to earlier proposals making use of literature citation rates and the prior knowledge of the analyst, this method presents a thorough and nonsubjective approach. The formulation approaches the probability calculation as a clustering and random draw problem that incorporates few analytical method parameters meticulously estimated to reflect sensitivity and specificity of the system. The practicality of the method has been demonstrated and validated using real data and simulated analytical techniques.
Ionizing Collisions of Electrons with Radical Species OH, H2 O2 and HO2; Theoretical Calculations
Joshipura, K. N.; Pandya, S. H.; Vaishnav, B. G.; Patel, U. R.
2016-05-01
In this paper we present our calculated total ionization cross sections (TICS) of electron impact on radical targets OH, H2 O2 and HO2 at energies from threshold to 2000 eV. Reactive species such as these pose difficulties in measurements of electron scattering cross sections. No measured data have been reported in this regard except an isolated TICS measurement on OH radical, and hence the present work on the title radicals hold significance. These radical species are present in an environment in which water molecules undergo dissociation (neutral or ionic) in interactions with photons or electrons. The embedding environments could be quite diverse, ranging from our atmosphere to membranes of living cells. Ionization of OH, H2 O2 or HO2 can give rise to further chemistry in the relevant bulk medium. Therefore, it is appropriate and meaningful to examine electron impact ionization of these radicals in comparison with that of water molecules, for which accurate da are available. For the OH target single-centre scattering calculations are performed by starting with a 4-term complex potential, that describes simultaneous elastic plus inelastic scattering. TICS are obtained from the total inelastic cross sections in the complex scattering potential - ionization contribution formalism , a well established method. For H2 O2 and HO2 targets, we employ the additivity rule with overlap or screening corrections. Detailed results will be presented in the Conference.
Energy Technology Data Exchange (ETDEWEB)
NONE
2005-09-15
The European Commission decided in 2001 an analysis program to reduce the atmospheric emissions. This report presents different limit scenari for France in 2020 (the reference scenari and the MTFR scenari, Maximum Technically Feasible Reduction), optimized scenari calculated by the RAINS model (Regional Air Pollution Information and Simulation), the costs of the scenari calculated with RAINS and the cost-benefit analysis of the strategy CAFE. From the study results, the benefits are higher than the costs, even with the most ambitious scenari. At an european level the emission reduction strategies have no effect on the employment but an impact on the Gross Domestic Product (decrease between 0,04 % and 0,12 % in function of the scenari). (A.L.B.)
Chikayama, Eisuke; Shimbo, Yudai; Komatsu, Keiko; Kikuchi, Jun
2016-04-14
NMR spectroscopy is a powerful method for analyzing metabolic mixtures. The information obtained from an NMR spectrum is in the form of physical parameters, such as chemical shifts, and construction of databases for many metabolites will be useful for data interpretation. To increase the accuracy of theoretical chemical shifts for development of a database for a variety of metabolites, the effects of sets of conformations (structural ensembles) and the levels of theory on computations of theoretical chemical shifts were systematically investigated for a set of 29 small molecules in the present study. For each of the 29 compounds, 101 structures were generated by classical molecular dynamics at 298.15 K, and then theoretical chemical shifts for 164 (1)H and 123 (13)C atoms were calculated by ab initio quantum chemical methods. Six levels of theory were used by pairing Hartree-Fock, B3LYP (density functional theory), or second order Møller-Plesset perturbation with 6-31G or aug-cc-pVDZ basis set. The six average fluctuations in the (1)H chemical shift were ±0.63, ± 0.59, ± 0.70, ± 0.62, ± 0.75, and ±0.66 ppm for the structural ensembles, and the six average errors were ±0.34, ± 0.27, ± 0.32, ± 0.25, ± 0.32, and ±0.25 ppm. The results showed that chemical shift fluctuations with changes in the conformation because of molecular motion were larger than the differences between computed and experimental chemical shifts for all six levels of theory. In conclusion, selection of an appropriate structural ensemble should be performed before theoretical chemical shift calculations for development of an accurate database for a variety of metabolites.
Arzoumanian, E.; Es-Sebbar, Et.; Romanzin, C.; Perrier, S.; Bénilan, Y.; Gazeau, M.-C.
2008-09-01
This paper presents studies performed in the frame of the SETUP program (a French acronym for Experimental and Theoretical Simulations Useful for Planetology). The final goal of this project is to perform representative simulations of Titan's atmosphere and to be able to determine the physicochemical processes involved in its atmosphere. The simulation experiments will be performed in a reactor where an initial gas mixture will be exposed, for the first time, to both major energy sources (electrons and photons) that are responsible for the chemical evolution of Titan's atmosphere. Thus, the complex chemistry between N atoms and CH3, CH2, CH fragments, issued from electron dissociation of N2 and photodissociation of CH4 respectively, will be initiated. For these simulation experiments, we are planning to use a pulsed excimer KrF laser delivering photons at 248 nm to dissociate methane via a multiphotonic process because the Lyman-α radiation, mainly responsible for the dissociation of this compound in the upper atmosphere, cannot be easily reproduced in the laboratory. A first attempt to check for the energetic equivalence of the two processes - 2 photons at 248 nm vs. one single photon at Lyman-α - has already been performed and a more extensive re-examination of the methane photolysis at both wavelengths has been undertaken. The available literature indeed provides contradictory results for the methane's primary photolytic scheme at Lyman-α and no studies at all have been performed yet to establish the different photolytic decomposition pathways at 248 nm. One has to note that the available literature provides contradictory results for methane's primary photolytic scheme at Lyman-α and no studies at all have been performed yet to establish the different photolytic decomposition pathways at 248 nm. Thus, a re-examination of the methane photolysis at both wavelengths has been undertaken. Photolysis of methane has been carried out using a photochemical classic
Ichikawa, Kazuhide; Fukushima, Akinori; Ishihara, Yoshio; Isaki, Ryuichiro; Takeguchi, Toshio; Tachibana, Akitomo; 10.1016/j.theochem.2009.08.026
2009-01-01
We investigate a reaction of boron trichloride (BCl3) with iron(III) hydroxide (Fe(OH)3) by ab initio quantum chemical calculation as a simple model for a reaction of iron impurities in BCl3 gas. We also examine a reaction with water. We find that compounds such as Fe(Cl)(OBCl2)2(OHBCl2) and Fe(Cl)2(OBCl2)(OHBCl2) are formed while producing HCl and reaction paths to them are revealed. We also analyze the stabilization mechanism of these paths using newly-developed interaction energy density derived from electronic stress tensor in the framework of the Regional DFT (Density Functional Theory) and Rigged QED (Quantum ElectroDynamics).
Energy Technology Data Exchange (ETDEWEB)
Huang, Guimei; Zhang, Xia; Fan, Yuhua; Bi, Caifeng; Yan, Xingchen; Zhang, Zhongyu; Zhang, Nan [Ocean Univ. of China, Qingdao (China)
2013-10-15
A new complex [Ni(phen)(C{sub 9}H{sub 8}Br{sub 2}NO{sub 3}){sub 2}·2CH{sub 3}OH·2H{sub 2}O] [phen: 1,10-phenanthroline C{sub 9}H{sub 8}Br{sub 2}NO{sub 3}: 3,5-dibromo-L-tyrosine] was synthesized and characterized by IR, elemental analysis and single crystal X-ray diffraction. X-ray crystallography shows that Ni(II) ion is six-coordinated. The Ni(II) ion coordinates with four nitrogen atoms and two oxygen atoms from three ligands, forming a mononuclear Ni(II) complex. The crystal crystallizes in the Orthorhombic system, space group P2{sub 1}2{sub 1}2 with a = 12.9546 A, b = 14.9822 A, c = 9.9705 A, V = 1935.2 A, Z = 1, F(000) = 1008, S = 0.969, ρ{sub calcd} = 1.742 g·cm{sup -3}, μ = 4.688 mm{sup -1}, R{sub 1} = 0.0529 and wR{sub 2} = 0.0738 for 3424 observed reflections (I > 2σ(I)). Theoretical study of the title complex was carried out by density functional theory (DFT) method and the B3LYP method employing the 6-3l+G{sup *} basis set. The energy gap between HOMO and LUMO indicates that this complex is prone to interact with DNA. CCDC: 908041.
Seo, Jaemyeong Mango; Ganbat, Gantuya; Han, Ji-Young; Baik, Jong-Jin
2017-02-01
Many big cities around the world are located near mountains. In city-mountain regions, thermally and topographically forced local winds are produced and they affect the transport of pollutants emitted into the urban atmosphere. A better understanding of the dynamics of thermally and topographically forced local winds is necessary to improve the prediction of local winds and to cope with environmental problems. In this study, we theoretically examine the interactions of urban breezes with mountain slope winds in the presence of basic-state wind within the context of the response of a stably stratified atmosphere to prescribed thermal and mechanical forcing. The interactions between urban breezes and mountain slope winds are viewed through the linear superposition of individual analytical solutions for urban thermal forcing, mountain thermal forcing, and mountain mechanical forcing. A setting is considered in which a city is located downwind of a mountain. In the nighttime, in the mountain-side urban area, surface/near-surface horizontal flows induced by mountain cooling and mountain mechanical forcing cooperatively interact with urban breezes, resulting in strengthened winds. In the daytime, in the urban area, surface/near-surface horizontal flows induced by mountain heating are opposed to urban breezes, giving rise to weakened winds. It is shown that the degree of interactions between urban breezes and mountain slope winds is sensitive to mountain height and basic-state wind speed. Particularly, a change in basic-state wind speed affects not only the strength of thermally and mechanically induced flows (internal gravity waves) but also their vertical wavelength and decaying rate. The examination of a case in a setting in which a city is located upwind of a mountain reveals that basic-state wind direction is an important factor that significantly affects the interactions of urban breezes with mountain slope winds.
Lin, Chun Che; Xiao, Zhi Ren; Guo, Guang-Yu; Chan, Ting-Shan; Liu, Ru-Shi
2010-03-10
The orthophosphate host family, A(I)B(II)PO(4) (A(I) = monovalent cation, B(II) = divalent cation), has recently been made available as phosphors that combine with near-UV lighting chips for use in solid-state white light-emitting diodes (LEDs). This study elucidates the crystalline structure and lattice parameters of the products via a solid-state reaction, using powder X-ray diffraction (XRD) and GSAS refinement. The versatility of the phosphor host A(I)B(II)PO(4) is established by examining isovalent substitutions of four cations in the structure-Li or K for A(I), Sr or Ba for B(II)-and three doped activators, RE = Eu(2+), Tb(3+), and Sm(3+). The luminescence properties, decay time, and Commission Internationale de l'Eclairage (CIE) chromaticity index are determined for various concentrations of these activators and metal constituents of the host. The thermal stabilities of all of these compounds are determined for the first time from the crystal structure and the coordination environment of the rare-earth metal. The morphology, composition, and particle size were measured in detail. Finally, density functional calculations were performed using the generalized gradient approximation plus an on-site Coulombic interaction correction (GGA+U) scheme to investigate the electronic structures of the KSrPO(4) system. A concise model was proposed to explain the luminescence mechanism.
Marchewka, M. K.; Drozd, M.; Janczak, J.
2011-08-01
The N-(4-nitrophenyl)-β-alanine in crystalline form directly by the addition of 4-nitroaniline to the acrylic acid in aqueous solution has been obtained. The title β-alanine derivative crystallizes in the P2 1/ c space group of monoclinic system with four molecules per unit cell. The X-ray geometry of β-alanine derivative molecule has been compared with those obtained by molecular orbital calculations corresponding to the gas phase. In the crystal the molecules related by an inversion center interact via symmetrically equivalent O-H⋯O hydrogen bonds with O⋯O distance of 2.656(2) Å forming a dimeric structure. The dimers of β-alanine derivative weakly interact via N-H⋯O hydrogen bonds between the H atom of β-amine groups and one of O atom of nitro groups. The room temperature powder vibrational (infrared and Raman) measurements are in accordance with the X-ray analysis. In aqueous solution of 4-nitroaniline and acrylic acid, the double C dbnd C bond of vinyl group of acrylic acid breaks as result of 4-nitroaniline addition.
Marchewka, M K; Drozd, M; Janczak, J
2011-08-15
The N-(4-nitrophenyl)-β-alanine in crystalline form directly by the addition of 4-nitroaniline to the acrylic acid in aqueous solution has been obtained. The title β-alanine derivative crystallizes in the P2(1)/c space group of monoclinic system with four molecules per unit cell. The X-ray geometry of β-alanine derivative molecule has been compared with those obtained by molecular orbital calculations corresponding to the gas phase. In the crystal the molecules related by an inversion center interact via symmetrically equivalent O-H···O hydrogen bonds with O···O distance of 2.656(2) Å forming a dimeric structure. The dimers of β-alanine derivative weakly interact via N-H···O hydrogen bonds between the H atom of β-amine groups and one of O atom of nitro groups. The room temperature powder vibrational (infrared and Raman) measurements are in accordance with the X-ray analysis. In aqueous solution of 4-nitroaniline and acrylic acid, the double CC bond of vinyl group of acrylic acid breaks as result of 4-nitroaniline addition.
Theoretical calculations of the high-pressure phases of ZnF2 and CdF2
Wu, X.; Wu, Z.
2006-04-01
First-principles calculations based on density functional theory were used to study the high-pressure phases of both ZnF2 and CdF2. We found that the sequence of the pressure-induced phase transitions is: Rutile (P42/mnm) ↦ CaCl2 (Pnnm) ↦ PdF2 (Pa-3) and CaF2 (Fm3m) ↦ PbCl2 (Pnma) ↦ Ni2In (P63/mmc) for ZnF2 and CdF2 respectively. In ZnF2 the behavior of the ground-state total energy, of the Gibbs free energy and of the lattice constant vs. pressure shown that the phase transition at 4 GPa from the rutile-type phase to the CaCl2-type phase is a second-order phase transition. The mechanism of the structural change was also revealed by the transition from the PbCl2-type phase to the Ni2In-type phase in CdF2. Moreover, the high-pressure behavior of divalent metal fluorides was compared and discussed.
Microscopic Theoretical Calculations ofR-Line Thermal Shifts and Broadenings of MgO:Cr3+
Institute of Scientific and Technical Information of China (English)
MA DongPing; LIU YanYun; MA Ning; CHEN JuRong
2002-01-01
By taking into account all the irreducible representations and their components in t he electron-phononinteraction (EPI) as well as all the levels and the admixtures of basic wavefunctions within d3 elect ronic configuration,the values of all the parameters in the expressions of thermal shift (TS) and thermal broadening (TB) due to EPI forthe ground level, R level and R line of MgO:Cr3+ have microscopically been evaluated; and then, TS and TB of R lineand various contributions to them have uniformly been calculated. The results arc in very good agreement with theexperimental data. It is found that all the three terms of TS due to EPI are red shifts; the Raman term is the largestone, and the optical-branch term and neighbor-level term are important for TS; the contribution to TS from thermalexpansion is bluc shift, which is also important. The R-line TS of MgO:Cr3+ comes from the first-order term of EPI. Theelastic Raman scattering of acoustic phonons plays a dominant role in R-line TB of MgO:Cr3+. For both TS and TB,it is very important to take into account all the admixtures of basic wavefunctions within d3 electronic configuration.
Thamilarasan, V; Sengottuvelan, N; Sudha, A; Srinivasan, P; Siva, A
2015-01-01
Manganese(III) complex (1) [Mn(8-hq)3] (where 8-hq=8-hydroxyquinoline) has been synthesized and characterized by elemental, spectral (UV-vis, FT-IR) and thermal analysis. The structure of complex (1) has been determined by single crystal X-ray diffraction studies and the configuration around manganese(III) ion was elongated octahedral coordination geometry. Density functional theory calculations were performed for ligand and its complex. Binding studies of ligand and complex 1 with calf thymus DNA (CT-DNA) was investigated by absorption, fluorescence, circular dichroic (CD) spectroscopy and viscosity measurements. Absorption spectral studies revealed that ligand and complex 1 binds to DNA groove and its intrinsic binding strength has been found to be 2.57×10(4) and 2.91×10(4)M(-1). A molecular docking study confirm that the complex 1 is a minor groove binder and was stabilized through hydrogen bonding interactions. Complex 1 exhibits a good binding propensity to bovine serum albumin (BSA) protein. The in vitro cytotoxicity study of complex 1 on breast cancer cell line (MCF-7) indicate that it has the potential to act as effective anticancer drug, with IC50 values of 3.25μM. The ligand and its complex have been screened for antimicrobial activities and the complex showed better antimicrobial activity than the free ligand.
Energy Technology Data Exchange (ETDEWEB)
Wang, Xiaoyan; Zhang, Zhongju [Ocean University of China, College of Chemistry and Chemical Engineering, Qingdao (China); Zhang, Luo; Wang, Xin [Ocean University of China, Institute of Material Science and Engineering, Qingdao (China)
2016-05-15
The morphologies of the materials have strong effects on their performance in particular applications. In our experiment, we synthesized LaPO{sub 4} successfully by the typical hydrothermal method in acidic conditions. The morphologies, preferred orientation and crystal facets are characterized by scanning electron microscopy, selected-area electron diffraction and high-resolution transmission electron microscopy. Combining the experimental findings, the surface energies of two major surfaces, (110) and (031) planes, were calculated using density functional theory methods. The theoretical calculations on the slabs surface energies were performed to simulate the shape of nanoparticles by the Wulff construction. The experimental results indicate that LaPO{sub 4} prepared in this work shows rodlike structure. The equilibrium shape of clava with large length-diameter ratio is achieved. With increasing hydrogen ion concentration in solutions, the morphologies present as sticks and their length-diameter ratios tend bigger, which is consistent with experimental results to a great extent. (orig.)
Fu, Weitao; Chen, Lingfeng; Wang, Zhe; Kang, Yanting; Wu, Chao; Xia, Qinqin; Liu, Zhiguo; Zhou, Jianmin; Liang, Guang; Cai, Yuepiao
2017-02-01
The activation and overexpression of fibroblast growth factor receptors (FGFRs) are highly correlated with a variety of cancers. Most small molecule inhibitors of FGFRs selectively target FGFR1-3, but not FGFR4. Hence, designing highly selective inhibitors towards FGFR4 remains a great challenge because FGFR4 and FGFR1 have a high sequence identity. Recently, two small molecule inhibitors of FGFRs, ponatinib and AZD4547, have attracted huge attention. Ponatinib, a type II inhibitor, has high affinity towards FGFR1/4 isoforms, but AZD4547, a type I inhibitor of FGFR1, displays much reduced inhibition toward FGFR4. In this study, conventional molecular dynamics (MD) simulations, molecular mechanics/generalized Born surface area (MM/GBSA) free energy calculations and umbrella sampling (US) simulations were carried out to reveal the principle of the binding preference of ponatinib and AZD4547 towards FGFR4/FGFR1. The results provided by MM/GBSA illustrate that ponatinib has similar binding affinities to FGFR4 and FGFR1, while AZD4547 has much stronger binding affinity to FGFR1 than to FGFR4. A comparison of the individual energy terms suggests that the selectivity of AZD4547 towards FGFR1 versus FGFR4 is primarily controlled by the variation of the van der Waals interactions. The US simulations reveal that the PMF profile of FGFR1/AZD4547 has more peaks and valleys compared with that of FGFR4/AZD4547, suggesting that the dissociation process of AZD4547 from FGFR1 are easily trapped into local minima. Moreover, it is observed that FGFR1/AZD4547 has much higher PMF depth than FGFR4/AZD4547, implying that it is more difficult for AZD4547 to escape from FGFR1 than from FGFR4. The physical principles provided by this study extend our understanding of the binding mechanisms and provide valuable guidance for the rational design of FGFR isoform selective inhibitors.
Lim, Sara N.; Pradhan, Anil K.; Nahar, Sultana N.
2013-06-01
When used with X-ray radiotherapy, heavy elements (high atomic number Z or HZ) such as gold(Au) and platinum(Pt) have the potential to greatly sensitize and enhance the damage to tumor tissues. While HZ radiosensitization has been shown to be higly effective in reducing tumor sizes, much work still needs to be done to determine the ideal X-ray energy/energy spectrum. The likelihood of photoelectric absorption of X-rays that result in the production of cell-killing Auger electrons relative to the photon scatter in an HZ sensitized tumor has to be determined for treatments using X-rays from various sources and energies to assess their efficacy. In this report, we present computations that outline the dependence of photoelectric absorption on X-ray energy. The relative X-ray absorption by a radiosensitized tumor was calculated to contrast the efficacy of different X-ray sources in Auger electron production at different tumor depths. Enhanced photoabsorption of low-energy X-rays from broadband sources in the keV range is shown to be much higher than from those in the MeV range. In addition, with the use of the Monte Carlo code package Geant4, we present the total X-ray energy deposited into a radiosensitized tumor located at different depths in a phantom. The enhancement in radiation dose deposition will also be analysed at the microscopic cellular level to determine the HZ radiosensitizer concentration required. Potential use of monochromatic X-rays for more precise HZ radiosensitization will also be described.
Petrescu, M I
2012-10-01
The calculation of the hardness of Mo and W disulfides using a crystallo-chemical model provides a unique opportunity to obtain separate quantitative information on the maximum hardness H(max) governed by strong intra-layer covalent bonds acting within the (0001) plane versus the minimum hardness H(min) governed by weak inter-layer van der Waals bonds acting along the c-axis of the hexagonal lattice. The penetration hardness derived from fundamental crystallo-chemical data (confirmed by experimental determinations) proved to be far lower in MS(2) (M = Mo, W) than in graphite and hexagonal BN, both for H(max) (H(graph)/H(MoS2) = 3.85; H(graph)/H(WS2) = 3.60; H(hBN)/H(MoS2) = 2.54; H(hBN)/H(WS2) = 2.37) as well as for H(min) (H(graph)/H(MoS2) = 6.22; H(graph)/H(WS2) = 5.87; H(hBN)/H(MoS2) = 4.72; H(hBN)/H(WS2) = 4.46). However, the gap between H(max) and H(min) is considerably larger in MS(2) (M = Mo,W), as indicated by H(max)/H(min) being 279 in 2H-MoS(2), 282 in 2H-WS(2), 173 in graphite and 150 in hBN. The gap was found to be even larger in MS(2) (M = Mo, W) nanostructures. These findings help to explain the excellent properties of MS(2) (M = Mo, W) as solid lubricants in high tech fields, either as bulk 2H crystals (inter-layer shear and peeling off lubricating mechanisms), or especially as onion-like fullerene nanoparticles (rolling/sliding mechanisms).
Zhang, Xueli; Gong, Xuedong
2014-08-04
Nitrogen-rich heterocyclic bases and oxygen-rich acids react to produce energetic salts with potential application in the field of composite explosives and propellants. In this study, 12 salts formed by the reaction of the bases 4-amino-1,2,4-trizole (A), 1-amino-1,2,4-trizole (B), and 5-aminotetrazole (C), upon reaction with the acids HNO3 (I), HN(NO2 )2 (II), HClO4 (III), and HC(NO2 )3 (IV), are studied using DFT calculations at the B97-D/6-311++G** level of theory. For the reactions with the same base, those of HClO4 are the most exothermic and spontaneous, and the most negative Δr Gm in the formation reaction also corresponds to the highest decomposition temperature of the resulting salt. The ability of anions and cations to form hydrogen bonds decreases in the order NO3 (-) >N(NO2 )2 (-) >ClO4 (-) >C(NO2 )3 (-) , and C(+) >B(+) >A(+) . In particular, those different cation abilities are mainly due to their different conformations and charge distributions. For the salts with the same anion, the larger total hydrogen-bond energy (EH,tot ) leads to a higher melting point. The order of cations and anions on charge transfer (q), second-order perturbation energy (E2 ), and binding energy (Eb ) are the same to that of EH,tot , so larger q leads to larger E2 , Eb , and EH,tot . All salts have similar frontier orbitals distributions, and their HOMO and LUMO are derived from the anion and the cation, respectively. The molecular orbital shapes are kept as the ions form a salt. To produce energetic salts, 5-aminotetrazole and HClO4 are the preferred base and acid, respectively. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Energy Technology Data Exchange (ETDEWEB)
Sheu, Hong-Li; Boopalachandran, Praveenkumar [Department of Chemistry, Texas A& M University, College Station, TX 77843-3255 (United States); Kim, Sunghwan [National Center for Biotechnology Information, National Library of Medicine, National Institutes of Health, Department of Health and Human Services, 8600 Rockville Pike, Bethesda, MD 20894 (United States); Laane, Jaan, E-mail: laane@chem.tamu.edu [Department of Chemistry, Texas A& M University, College Station, TX 77843-3255 (United States)
2015-07-29
Highlights: • The structures of 2,3,5,6-tetrafluoropyridine for its S{sub 0} and S{sub 1}(π, π{sup ∗}) states have been calculated. • TFPy is rigidly planar in its ground electronic state, but is quasi-planar and floppy in S{sub 1}. • The barrier to planarity is 30 cm{sup −1} in the excited state. • The observed vibrational frequencies for both states agree well with the computations. • A ring-bending potential energy function for the S{sub 1}(π, π{sup ∗}) state was proposed. - Abstract: Infrared and Raman spectra of 2,3,5,6-tetrafluoropyridine (TFPy) were recorded and vibrational frequencies were assigned for its S{sub 0} electronic ground states. Ab initio and density functional theory (DFT) calculations were used to complement the experimental work. The lowest electronic excited state of this molecule was investigated with ultraviolet absorption spectroscopy and theoretical CASSCF calculations. The band origin was found to be at 35,704.6 cm{sup −1} in the ultraviolet absorption spectrum. A slightly puckered structure with a barrier to planarity of 30 cm{sup −1} was predicted by CASSCF calculations for the S{sub 1}(π, π{sup ∗}) state. Lower frequencies for the out-of-plane ring bending vibrations for the electronic excited state result from the weaker π bonding within the pyridine ring.
Directory of Open Access Journals (Sweden)
Maliszewska Weronika
2016-03-01
Full Text Available The area of interests of nuclear physics are studies of reactions, wherein atomic nuclei of projectile collide with target nuclei. An amount of energy lost by projectile nucleus during its passing through the target is a major issue – it is important to know how charged particles interact with matter. It is possible to afford this knowledge by using theoretical programs that calculate energy loss applying the Bethe-Bloch equation. Hadrontherapy, which is a field of still growing interest, is based on the interactions of charged particles with matter. Therefore, there exists a need of creating a simple model that could be used to the calculation of dose distributions in biological matter. Two programs (SRIM, Xeloss, used to the calculation of energy loss by nuclear physicist, have been adapted to determine the dose distributions in analogues of human tissues. Results of the calculations with those programs for beams used in hadrontherapy (e.g. 1H, 12C will be compared with experimental data available in references.
Dai, Zuyang; Gao, Shuming; Wang, Jia; Mo, Yuxiang
2014-10-14
The torsional energy levels of CH3OH(+), CH3OD(+), and CD3OD(+) have been determined for the first time using one-photon zero kinetic energy photoelectron spectroscopy. The adiabatic ionization energies for CH3OH, CH3OD, and CD3OD are determined as 10.8396, 10.8455, and 10.8732 eV with uncertainties of 0.0005 eV, respectively. Theoretical calculations have also been performed to obtain the torsional energy levels for the three isotopologues using a one-dimensional model with approximate zero-point energy corrections of the torsional potential energy curves. The calculated values are in good agreement with the experimental data. The barrier height of the torsional potential energy without zero-point energy correction was calculated as 157 cm(-1), which is about half of that of the neutral (340 cm(-1)). The calculations showed that the cation has eclipsed conformation at the energy minimum and staggered one at the saddle point, which is the opposite of what is observed in the neutral molecule. The fundamental C-O stretch vibrational energy level for CD3OD(+) has also been determined. The energy levels for the combinational excitation of the torsional vibration and the fundamental C-O stretch vibration indicate a strong torsion-vibration coupling.
Cappelletti, David; Aquilanti, Vincenzo; Bartocci, Alessio; Nunzi, Francesca; Tarantelli, Francesco; Belpassi, Leonardo; Pirani, Fernando
2016-07-14
Gas phase collisions of O2 by CH4, CF4, and CCl4 have been investigated with the molecular beam technique by measuring both the integral cross section value, Q, and its dependence on the collision velocity, v. The adopted experimental conditions have been appropriate to resolve the oscillating "glory" pattern, a quantum interference effect controlled by the features of the intermolecular interaction, for all the three case studies. The analysis of the Q(v) data, performed by adopting a suitable representation of the intermolecular potential function, provided the basic features of the anisotropic potential energy surfaces at intermediate and large separation distances and information on the relative role of the physically relevant types of contributions to the global interaction. The present work demonstrates that while O2-CH4 and O2-CF4 are basically bound through the balance between size (Pauli) repulsion and dispersion attraction, an appreaciable intermolecular bond stabilization by charge transfer is operative in O2-CCl4. Ab initio calculations of the strength of the interaction, coupled with detailed analysis of electronic charge displacement promoted by the formation of the dimer, fully rationalizes the experimental findings. This investigation indicates that the interactions of O2, when averaged over its relative orientations, are similar to that of a noble gas (Ng), specifically Ar. We also show that the binding energy in the basic configurations of the prototypical Ng-CF4,CCl4 systems [ Cappelletti , D. ; Chem. Eur. J. 2015 , 21 , 6234 - 6240 ] can be reconstructed by using the interactions in Ng-F and Ng-Cl systems, previously characterized by molecular beam scattering experiments of state-selected halogen atom beams. This information is fundamental to approach the modeling of the weak intermolecular halogen bond. On the basis of the electronic polarizability, this also confirms [ Aquilanti , V. ; Angew. Chem., Int. Ed. 2005 , 44 , 2356 - 2360 ] that O2
Sarkar, Sougata; Chowdhury, Joydeep; Dutta, Soumen; Pal, Tarasankar
2016-12-01
calculations for these prescribed model systems were also carried out to have a plausible understanding of their equilibrium geometries and the vibrational wavenumbers. An idea about the molecular orientation of the adsorbate over nanocolloidal gold substrate is also documented.
Qu, Liu; Choy, Kwang-Leong; Wheatley, Richard
2016-02-01
Ceramic oxides that have high-temperature capabilities can be deposited on the superalloy components in aero engines and diesel engines to advance engine efficiency and reduce fuel consumption. This paper aims to study doping effects of Dy3+ and Y3+on the thermodynamic properties of ZrO2 synthesized via a sol-gel route for a better control of the stoichiometry, combined with molecular dynamics (MD) simulation for the calculation of theoretical properties. The thermal conductivity is investigated by the MD simulation and Clarke’s model. This can improve the understanding of the microstructure and thermodynamic properties of (DyY)Zr2O7 (DYZ) at the atomistic level. The phonon-defect scattering and phonon-phonon scattering processes are investigated via the theoretical calculation, which provides an effective way to study thermal transport properties of ionic oxides. The measured and predicted thermal conductivity of DYZ is lower than that of 4 mol % Y2O3 stabilized ZrO2 (4YSZ). It is discovered that DYZ is thermochemically compatible with Al2O3 at 1300 °C, whereas at 1350 °C DYZ reacts with Al2O3 forming a small amount of new phases.
Energy Technology Data Exchange (ETDEWEB)
Romanowski, Stela Maris de M.; Friedermann, Geraldo R.; Mangrich, Antonio S.; Hermann, Monique de F.; Nakagaki, Shirley, E-mail: shirley@quimica.ufpr.b [Universidade Federal do Parana (UFPR), Curitiba, PR (Brazil). Dept. de Quimica; Machado, Sergio P.; Lima, Hugo Orofino [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Inst. de Quimica
2010-07-01
The synthesis and characterization of the manganese(II) complexes [Mn{sup II}(Hbpeten)] and [Mn{sup II}(Hbnbpeten)], where H{sub 3}bpeten and H{sub 3}bnbpeten are respectively [N,N'-bis-(2-hydroxybenzyl)- N-(2-pyridylmethyl)-N'-(2-hydroxyethyl)ethane-1,2-diamine] and [N,N'-bis-(5-nitro-2- hydroxybenzyl)-N'-(2-hydroxyethyl)ethane-1,2-diamine], are reported. The characterization was carried out by elemental analyses, cyclic voltammetry, spectroscopic methods (UV-Vis, FTIR, {sup 1}H NMR), electronic paramagnetic resonance spectroelectrochemistry (EPR) and theoretical DFT calculations. The electrochemistry and EPR spectroelectrochemistry data were consistent with the reduction of one of the nitro groups in free H{sub 3}bnbpeten and in the respective manganese(II) complex. These results were supported by DFT calculations, which showed that only one nitro group contributes to the LUMO. The theoretical data appear to be suitable to describe the electronic properties of the compounds. (author)
THEORETICAL CALCULATION OF MINIMUM WATER DROPS SEPARATED BY CYCLONE DEHYDRATOR%旋流式脱水器分离最小水滴理论计算
Institute of Scientific and Technical Information of China (English)
杨建勋
2012-01-01
The structure and working principle of the cyclone dehydrator are presented and the factors influencing its performance are analyzed. Starting from theoretical analysis, the method for calculating the minimum diameter of water drops separated by a cyclone dehydrator is also deduced, which has been verified by project practice. The result shows that the actual use effect agrees well with the theoretical calculation, which provides a useful reference for study, design and application of cyclone dehydrators.%介绍了旋流式的构造和工作原理，分析了影响性能的因素。通过对脱水器构造的剖析，找出叶片形状影响脱水效果的关键所在，从理论分析入手，推导出旋流式脱水器分离最小直径水滴的计算方法，并根据工程实践进行了检验。工程实践表明，实际应用效果与理论计算相符合。
Waggoner, E. G.; Phillips, P. S.; Viken, J. K.; Davis, W. H.
1985-01-01
NASA Langley and NASA Ames-Dryden have defined a variable-sweep transition-flight experiment utilizing the F-14 aircraft to enhance understanding of the interaction of crossflow and Tollmien-Schlichting instabilities on a laminar-boundary-layer transition. The F-14 wing outer panel will be modified to generate favorable pressure gradients on the upper wing surface over a wide range of flight conditions. Extensive computations have been performed using two-dimensional and three-dimensional transonic analysis codes. Flight-test and computational data are compared and shown to validate the applicability of the three-dimensional codes (WBPPW and TAWFIVE). In addition, results from two preliminary glove designs derived from two different approaches to the design problem are presented. Advantages and disadvantages of each approach are identified, and it is concluded that coupling an analysis code with an automated design procedure yields a powerful code with distinct advantages over a 'cut-and-dry' approach.
Theoretical calculation of the Hall mobility of InNAs1− alloys when = 0.0–0.1
Indian Academy of Sciences (India)
Senem Aydogu; Mustafa Akarsu; Omer Ozbas
2012-01-01
The Hall mobility of InNAs1− semiconductor alloys is calculated by solving the Boltzmann transport equation using the iterative method. All the major scattering mechanisms are included in the calculations. The Hall mobilities of InAs and InN0.01As0.99 are presented in the temperature range of 30–600 K. It is shown that incorporation of even small amount of nitrogen leads to an abrupt reduction of the Hall mobility in InNAs1− at low temperatures. The effect of alloy random scattering on the Hall mobility of InNAs1− is examined at 77 and 300 K as the mole fraction x varies from 0.0 to 0.1. It is seen that the Hall mobility drops sharply up to = 0.02 for 77 K and reduces slowly as the temperature increases to 300 K compared to 77 K. The Hall mobilities calculated theoretically are compared with the experimental data available in the literature.
Rhodes, Charles Kirkham
2010-01-01
The fine-structure constant {\\alpha}, the dimensionless number that represents the strength of electromagnetic coupling in the limit of sufficiently low energy interactions, is the crucial fundamental physical parameter that governs a nearly limitless range of phenomena involving the interaction of radiation with materials. Ideally, the apparatus of physical theory should be competent to provide a calculational procedure that yields a quantitatively correct value for {\\alpha} and the physical basis for its computation. This study presents the first demonstration of an observationally anchored theoretical procedure that predicts a unique value for {\\alpha} that stands in full agreement with the best (~370 ppt) high-precision experimental determinations. In a directly connected cryptographic computation, the method that gives these results also yields the magnitude of the cosmological constant {\\Omega}{\\Lambda} in conformance with the observational data and the condition of perfect flatness ({\\Omega}{\\Lambda} +...
Pang, Sumei; Zhao, Yanying; Xin, Liu; Xue, Jiadan; Zheng, Xuming
2017-01-01
The vibration spectra of 5-(methylthio)-1,3,4-thiadiazole-2(3H)-thione (MTTN) in acetonitrile (CH3CN), methanol (CH3OH) and water (H2O) solvents were collected and evaluated via deuterium isotopic substitution Raman spectroscopic experiments. These experiments were combined with the quantum chemical theoretical calculations using the PCM solvent model and normal mode analysis. The results confirmed that the MTTN in CH3CN, CH3OH and H2O have hydrogen bonding (H-bonding) MTTN(solvent)n clusters that produce significantly different Raman intensity patterns in different solvents. Combined with the normal Raman assignment, most resonance Raman spectra were assigned to the vibration modes of the H-bonding MTTN(CH3CN), MTTN(CH3OH)3 and MTTN(H2O)3 clusters in CH3CN, CH3OH and H2O. The theoretically-predicted frequencies and intensities in different surrounding environments enabled reliable assignments of Raman bands. The intermolecular > NH ⋯ O and > NH ⋯ N H-bonding interactions are key constituents of stable thione structures in MTTN. This underlines the significant structural differences of MTTN in CH3CN, CH3OH and H2O. H-bonding perturbation of MTTN reveal important insights about the intermolecular excited state proton transfer (ESPT) reaction mechanisms in the Franck-Condon region structural dynamics of the thione → thiol tautomer in CH3OH and H2O.
Yang, Wanmin; Yang, Pengtao; Wang, Yanan; Li, Qiang
2017-09-01
The lower critical temperature Tc and critical current density Jc are serious weaknesses of SmBCO bulk superconductors fabricated in air for practical applications, because of the Sm3+/Ba2+ solid solution in Sm1+xBa2-xCu3Oy crystals. In this paper, high quality single domain SmBCO bulk samples S1 (ϕ20 mm) and S2 (ϕ32 mm) have been fabricated in air by a new Sm+011 TSIG method. The trapped field of the samples is 0.8 T and 1.15 T at liquid nitrogen temperature for the samples S1 and S2 respectively, which is the strongest trapped field of the SmBCO samples fabricated in air today. The theoretical formula for 3D trapped field distribution have been derived for a cylindrical model with uniformly distributed critical current density Jc based on the Biot Savart law; the cylindrical sample is divided into a series of concentric rings with the same width and thickness, the trapped field of the samples is the summation of magnetic field produced by all the rings, while the magnetic field generated by each ring was worked out by trapezoidal numerical integration based on the Biot Savart law with the critical current density Jc of the samples. It is found that the calculated field of the samples is well in agreement with the experimental results if the reasonable Jc of the samples is adopted. The theoretical calculation result also indicates that the larger the diameter and the thickness of the samples, the stronger the trapped flux density, but the optimal diameter/thickness ratio should be of a reasonable value around one, and it is not so good to fabricated samples with too larger diameter or thickness for practical applications.
Energy Technology Data Exchange (ETDEWEB)
Jin, L; Eldib, A; Li, J; Price, R; Ma, C [Fox Chase Cancer Center, Philadelphia, PA (United States)
2015-06-15
Purpose: Uneven nose surfaces and air cavities underneath and the use of bolus present complexity and dose uncertainty when using a single electron energy beam to plan treatments of nose skin with a pencil beam-based planning system. This work demonstrates more accurate dose calculation and more optimal planning using energy and intensity modulated electron radiotherapy (MERT) delivered with a pMLC. Methods: An in-house developed Monte Carlo (MC)-based dose calculation/optimization planning system was employed for treatment planning. Phase space data (6, 9, 12 and 15 MeV) were used as an input source for MC dose calculations for the linac. To reduce the scatter-caused penumbra, a short SSD (61 cm) was used. Our previous work demonstrates good agreement in percentage depth dose and off-axis dose between calculations and film measurement for various field sizes. A MERT plan was generated for treating the nose skin using a patient geometry and a dose volume histogram (DVH) was obtained. The work also shows the comparison of 2D dose distributions between a clinically used conventional single electron energy plan and the MERT plan. Results: The MERT plan resulted in improved target dose coverage as compared to the conventional plan, which demonstrated a target dose deficit at the field edge. The conventional plan showed higher dose normal tissue irradiation underneath the nose skin while the MERT plan resulted in improved conformity and thus reduces normal tissue dose. Conclusion: This preliminary work illustrates that MC-based MERT planning is a promising technique in treating nose skin, not only providing more accurate dose calculation, but also offering an improved target dose coverage and conformity. In addition, this technique may eliminate the necessity of bolus, which often produces dose delivery uncertainty due to the air gaps that may exist between the bolus and skin.
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
In this work,the relationship between electronic structure and hemocompatibility of oxygen deficient rutile TiO2-x was studied by both theoretical calculation and experimental study. Based on the local density functional theory,first-principals method was performed to calculate the electronic structure of rutile TiO2 with different oxygen vacancy concentration. In the range of less than 10% of (or equal) physically realistic O vacancy concentration,the band gap of rutile TiO2 increases with increasing O vacancy concentration,leading the TiO2 changes from a p-type to an n-type semiconductor. The valance band of TiO2 is predominated by O 2p orbital,while the conduction band is occupied by Ti 3d orbital for different O vacancy concentration. The O vacancy results in the occupation of electrons at the bottom of conduction band of TiO2,and the donor density increases with increasing O vacancy concentration. When materials come in contact with blood,the n-type semiconductor feature of oxygen deficient TiO2-x with the bottom of conduction band occupied by electrons would prevent charge transfer from fibrinogen into the surface of materials,thus inhibiting the aggregation and activation of platelets,therefore improving the hemocompatibility of rutile TiO2-x.
Astani, Elahe K; Heshmati, Emran; Chen, Chun-Jung; Hadipour, Nasser L
2016-07-01
A theoretical study at the level of density functional theory (DFT) was performed to characterize noncovalent intermolecular interactions, especially hydrogen bond interactions, in the active site of enzyme human androsterone sulphotransferase (SULT2A1/ADT). Geometry optimization, interaction energy, (2)H, (14)N, and (17)O electric field gradient (EFG) tensors, (1)H, (13)C, (17)O, and (15)N chemical shielding (CS) tensors, Natural Bonding Orbital (NBO) analysis, and quantum theory of atoms in molecules (QTAIM) analysis of this active site were investigated. It was found that androsterone (ADT) is able to form hydrogen bonds with residues Ser80, Ile82, and His99 of the active site. The interaction energy calculations and NBO analysis revealed that the ADT molecule forms the strongest hydrogen bond with Ser80. Results revealed that ADT interacts with the other residues through electrostatic and Van der Waals interactions. Results showed that these hydrogen bonds influence on the calculated (2)H, (14)N, and (17)O quadrupole coupling constants (QCCs), as well as (1)H, (13)C, (17)O, and (15)N CS tensors. The magnitude of the QCC and CS changes at each nucleus depends directly on its amount of contribution to the hydrogen bond interaction.
Baldenebro-López, Jesús; Báez-Castro, Alberto; Glossman-Mitnik, Daniel; Höpfl, Herbert; Cruz-Enríquez, Adriana; Miranda-Soto, Valentín; Parra-Hake, Miguel; Campos-Gaxiola, José J.
2017-02-01
cis-(±)-2,4,5-tris(pyridin-2-yl)imidazoline has been fully characterized by FT-IR, FT-Raman, UV-Vis and fluorescence spectroscopy, one- and two-dimensional NMR spectroscopy (1H, 1H-1H gCOSY, 1H-1H gNOESY,13C{1H} ATP, 1H-13C and 1H-15N gHSQC and 1H-13C gHMBC), high-resolution mass spectrometry (HR-FAB+), TG-DSC analysis and low-temperature single-crystal X-ray diffraction analysis. Additionally, the molecular geometry and the vibrational infrared and Raman frequencies were calculated by density functional theory using the M06/6-31G(d) level of theory, showing good agreement with the experimental results. The title compound showed interesting photophysical properties, which were studied experimentally in solution and in the solid state by UV-Vis and fluorescence spectroscopy and compared to the theoretically obtained parameters using TD-DFT calculations. Natural and Mulliken atomic charges and the molecular electrostatic potential (MEP) have been mapped.
Tanaka, Isao; Mizoguchi, Teruyasu; Yamamoto, Tomoyuki
2009-03-01
Both electron energy loss near edge structure (ELNES) spectroscopy and x-ray absorption near edge structure (XANES) spectroscopy provide information on the local structural and chemical environments of selected elements of interest. Recent technological progress in scanning transmission electron microscopy has enabled ELNES measurements with atomic column spatial resolution. Very dilute concentrations (nanograms per milliliter or ppb level) of dopants can be observed using third-generation synchrotron facilities when x-ray fluorescence is measured with highly efficient detectors. With such technical developments, ELNES and XANES have become established as essential tools in a large number of fields of natural science, including condensed matter physics, chemistry, mineralogy and materials science. In addition to these developments in experimental methodology, notable progress in reproducing spectra using theoretical methods has recently been made. Using first-principles methods, one can analyze and interpret spectra without reference to experiment. This is quite important since we are often interested in the analysis of exotic materials or specific atoms located at lattice discontinuities such as surfaces and interfaces, where appropriate experimental data are difficult to obtain. Using the structures predicted by reliable first-principles calculations, one can calculate theoretical ELNES and XANES spectra without too much difficulty even in such cases. Despite the fact that ELNES and XANES probe the same phenomenon—essentially the electric dipole transition from a core orbital to an unoccupied band—there have not been many opportunities for researchers in the two areas to meet and discuss. Theoretical calculations of ELNES spectra have been mainly confined to the electron microscopy community. On the other hand, the theory of XANES has been developed principally by researchers in the x-ray community. Publications describing the methods have been written more
Cazacu, Maria; Shova, Sergiu; Soroceanu, Alina; Machata, Peter; Bucinsky, Lukas; Breza, Martin; Rapta, Peter; Telser, Joshua; Krzystek, J; Arion, Vladimir B
2015-06-15
Mononuclear nickel(II), copper(II), and manganese(III) complexes with a noninnocent tetradentate Schiff base ligand containing a disiloxane unit were prepared in situ by reaction of 3,5-di-tert-butyl-2-hydroxybenzaldehyde with 1,3-bis(3-aminopropyl)tetramethyldisiloxane followed by addition of the appropriate metal(II) salt. The ligand H2L resulting from these reactions is a 2:1 condensation product of 3,5-di-tert-butyl-2-hydroxybenzaldehyde with 1,3-bis(3-aminopropyl)tetramethyldisiloxane. The resulting metal complexes, NiL·0.5CH2Cl2, CuL·1.5H2O, and MnL(OAc)·0.15H2O, were characterized by elemental analysis, spectroscopic methods (IR, UV-vis, X-band EPR, HFEPR, (1)H NMR), ESI mass spectrometry, and single crystal X-ray diffraction. Taking into account the well-known strong stabilizing effects of tert-butyl groups in positions 3 and 5 of the aromatic ring on phenoxyl radicals, we studied the one-electron and two-electron oxidation of the compounds using both experimental (chiefly spectroelectrochemistry) and computational (DFT) techniques. The calculated spin-density distribution and localized orbitals analysis revealed the oxidation locus and the effect of the electrochemical electron transfer on the molecular structure of the complexes, while time-dependent DFT calculations helped to explain the absorption spectra of the electrochemically generated species. Hyperfine coupling constants, g-tensors, and zero-field splitting parameters have been calculated at the DFT level of theory. Finally, the CASSCF approach has been employed to theoretically explore the zero-field splitting of the S = 2 MnL(OAc) complex for comparison purposes with the DFT and experimental HFEPR results. It is found that the D parameter sign strongly depends on the metal coordination geometry.
Preliminary Calculation of the EROI for the Production of Crude Oil and Light Oil Products in Russia
Directory of Open Access Journals (Sweden)
Alexander Safronov
2014-09-01
Full Text Available Russia is one of the world’s largest producers of energy resources. The production of energy resources in Russia is profitable both economically and in terms of energy production. Currently, Russian oil and gas companies have a policy of increasing energy efficiency, which will led to an increase in the energy return on investment (EROI of both oil and gas production as a whole, and of separate companies in particular. By our calculations, the EROI for oil production in Russia differs for the different companies, and in 2012 was in the range of 22–35:1. The EROI for light oil products in 2012 was in the range of 5–13:1.
Directory of Open Access Journals (Sweden)
Inseon Ryoo
Full Text Available PURPOSE: To evaluate the usefulness of dynamic susceptibility contrast (DSC enhanced perfusion MR imaging in predicting major genetic alterations in glioblastomas. MATERIALS AND METHODS: Twenty-five patients (M:F = 13∶12, mean age: 52.1±15.2 years with pathologically proven glioblastoma who underwent DSC MR imaging before surgery were included. On DSC MR imaging, the normalized relative tumor blood volume (nTBV of the enhancing solid portion of each tumor was calculated by using dedicated software (Nordic TumorEX, NordicNeuroLab, Bergen, Norway that enabled semi-automatic segmentation for each tumor. Five major glioblastoma genetic alterations (epidermal growth factor receptor (EGFR, phosphatase and tensin homologue (PTEN, Ki-67, O6-methylguanine-DNA methyltransferase (MGMT and p53 were confirmed by immunohistochemistry and analyzed for correlation with the nTBV of each tumor. Statistical analysis was performed using the unpaired Student t test, ROC (receiver operating characteristic curve analysis and Pearson correlation analysis. RESULTS: The nTBVs of the MGMT methylation-negative group (mean 9.5±7.5 were significantly higher than those of the MGMT methylation-positive group (mean 5.4±1.8 (p = .046. In the analysis of EGFR expression-positive group, the nTBVs of the subgroup with loss of PTEN gene expression (mean: 10.3±8.1 were also significantly higher than those of the subgroup without loss of PTEN gene expression (mean: 5.6±2.3 (p = .046. Ki-67 labeling index indicated significant positive correlation with the nTBV of the tumor (p = .01. CONCLUSION: We found that glioblastomas with aggressive genetic alterations tended to have a high nTBV in the present study. Thus, we believe that DSC-enhanced perfusion MR imaging could be helpful in predicting genetic alterations that are crucial in predicting the prognosis of and selecting tailored treatment for glioblastoma patients.
Hetmańczyk, Joanna; Hetmańczyk, Łukasz; Migdał-Mikuli, Anna; Mikuli, Edward
2015-02-05
The vibrational and reorientational motions of NH3 ligands and ClO4(-) anions were investigated by Fourier transform middle-infrared spectroscopy (FT-IR) in the high- and low-temperature phases of [Mn(NH3)6](ClO4)2. The temperature dependencies of full width at half maximum (FWHM) of the infrared bands at: 591 and 3385cm(-1), associated with: ρr(NH3) and νas(N-H) modes, respectively, indicate that there exist fast (correlation times τR≈10(-12)-10(-13)s) reorientational motions of NH3 ligands, with a mean values of activation energies: 7.8 and 4.5kJmol(-1), in the phase I and II, respectively. These reorientational motions of NH3 ligands are only slightly disturbed in the phase transition region and do not significantly contribute to the phase transition mechanism. Fourier transform far-infrared and middle-infrared spectra with decreasing of temperature indicated characteristic changes at the vicinity of PT at TC(c)=137.6K (on cooling), which suggested lowering of the crystal structure symmetry. Infrared spectra of [Mn(NH3)6](ClO4)2 were recorded and interpreted by comparison with respective theoretical spectra calculated using DFT method (B3LYP functional, LANL2DZ ECP basis set (on Mn atom) and 6-311+G(d,p) basis set (on H, N, Cl, O atoms) for the isolated equilibrium two models (Model 1 - separate isolated [Mn(NH3)6](2+) cation and ClO4(-) anion and Model 2 - [Mn(NH3)6(ClO4)2] complex system). Calculated optical spectra show a good agreement with the experimental infrared spectra (FT-FIR and FT-MIR) for the both models. Copyright © 2014 Elsevier B.V. All rights reserved.
Zavodnik, I B; Domanski, A V; Lapshina, E A; Bryszewska, M; Reiter, R J
2006-06-20
Melatonin, a pineal secretory product, has properties of both direct and indirect powerful antioxidant. The aim of the present study was to compare the radical-scavenging, structural and electronic properties of melatonin and tryptophan, precursor of melatonin. Using the alkoxyl- and peroxyl radical-generating systems [the organic peroxide-treated human erythrocytes and a cell-free system containing the azo-initiator 2,2'-azobis(2-amidinopropane)dihydrochloride], we evaluated the radical-scavenging effects of melatonin and tryptophan. Melatonin rather than tryptophan at concentrations of 100-2000 microM markedly inhibited membrane lipid peroxidation in human erythrocytes treated with organic hydroperoxide as well as radical-induced generation of luminol-dependent chemiluminescence. The apparent Stern-Volmer constants for inhibition of membrane lipid peroxidation by melatonin and tryptophan were estimated to be (0.23+/-0.05) x 10(4) M(-1) and (0.02+/-0.005) x 10(4) M(-1), respectively. The apparent Stern-Volmer constants for inhibition of azo-initiator-derived peroxyl radical generation by melatonin and tryptophan were determined to be (0.42+/-0.05) x 10(4) M(-1) and (0.04+/-0.01) x 10(4) M(-1), respectively. The structural and electronic properties of melatonin and its precursor, tryptophan, were determined theoretically by performing semi-empirical and ab initio calculations. The high radical-scavenging properties of melatonin may be explained by the high surface area value and high dipole moment value. From the thermodynamic standpoint, based on our calculations, N(1)-acetyl-N(2)-formyl-5-methoxykynuramine (AFMK), was the most stable end oxidative product of melatonin.
Hartzell, S.; Guatteri, Mariagiovanna; Mai, P.M.; Liu, P.-C.; Fisk, M. R.
2005-01-01
In the evolution of methods for calculating synthetic time histories of ground motion for postulated earthquakes, kinematic source models have dominated to date because of their ease of application. Dynamic models, however, which incorporate a physical relationship between important faulting parameters of stress drop, slip, rupture velocity, and rise time, are becoming more accessible. This article compares a class of kinematic models based on the summation of a fractal distribution of subevent sizes with a dynamic model based on the slip-weakening friction law. Kinematic modeling is done for the frequency band 0.2 to 10.0. Hz, dynamic models are calculated from 0.2 to 2.0. Hz. The strong motion data set for the 1994 Northridge earthquake is used to evaluate and compare the synthetic time histories. Source models are propagated to the far field by convolution with 1D and 3D theoretical Green’s functions. In addition, the kinematic model is used to evaluate the importance of propagation path effects: velocity structure, scattering, and nonlinearity. At present, the kinematic model gives a better broadband fit to the Northridge ground motion than the simple slip-weakening dynamic model. In general, the dynamic model overpredicts rise times and produces insufficient shorter-period energy. Within the context of the slip-weakening model, the Northridge ground motion requires a short slip-weakening distance, on the order of 0.15 m or less. A more complex dynamic model including rate weakening or one that allows shorter rise times near the hypocenter may fit the data better.
Xie, Yujun; Ge, Yuwei; Peng, Qian; Li, Conggang; Li, Qianqian; Li, Zhen
2017-02-21
Long-lived phosphorescence at room temperature (RTP) from pure organic molecules is rare. Recent research reveals various crystalline organic molecules can realize RTP with lifetimes extending to the magnitude of second. There is little research on how molecular packing affecting RTP. Three compounds are designed with similar optical properties in solution, but tremendously different solid emission characteristics. By investigating the molecular packing arrangement in single crystals, it is found that the packing style of the compact face to face favors of long phosphorescence lifetime and high photoluminescence efficiency, with the lifetime up to 748 ms observed in the crystal of CPM ((9H-carbazol-9-yl)(phenyl)methanone). Theoretical calculation analysis also reveals this kind of packing style can remarkably reduce the singlet excited energy level and prompt electron communication between dimers. Surprisingly, CPM has two very similar single crystals, labeled as CPM and CPM-A, with almost identical crystal data, and the only difference is that molecules in CPM-A crystal take a little looser packing arrangement. X-ray diffraction and cross-polarization under magic spinning (13) C NMR spectra double confirm that they are different crystals. Interestingly, CPM-A crystal shows negligible RTP compared to the CPM crystal, once again proving that the packing style is critical to the RTP property.
Yang, M; Virshup, G; Clayton, J; Zhu, X R; Mohan, R; Dong, L
2010-03-07
We discovered an empirical relationship between the logarithm of mean excitation energy (ln Im) and the effective atomic number (EAN) of human tissues, which allows for computing patient-specific proton stopping power ratios (SPRs) using dual-energy CT (DECT) imaging. The accuracy of the DECT method was evaluated for 'standard' human tissues as well as their variance. The DECT method was compared to the existing standard clinical practice-a procedure introduced by Schneider et al at the Paul Scherrer Institute (the stoichiometric calibration method). In this simulation study, SPRs were derived from calculated CT numbers of known material compositions, rather than from measurement. For standard human tissues, both methods achieved good accuracy with the root-mean-square (RMS) error well below 1%. For human tissues with small perturbations from standard human tissue compositions, the DECT method was shown to be less sensitive than the stoichiometric calibration method. The RMS error remained below 1% for most cases using the DECT method, which implies that the DECT method might be more suitable for measuring patient-specific tissue compositions to improve the accuracy of treatment planning for charged particle therapy. In this study, the effects of CT imaging artifacts due to the beam hardening effect, scatter, noise, patient movement, etc were not analyzed. The true potential of the DECT method achieved in theoretical conditions may not be fully achievable in clinical settings. Further research and development may be needed to take advantage of the DECT method to characterize individual human tissues.
Nishida, Shinsuke; Fukui, Kozo; Morita, Yasushi
2014-02-01
The stable tetrathiafulvalene (TTF)-linked 6-oxophenalenoxyl neutral radical exhibits a spin-center transfer with a continuous color change in solution caused by an intramolecular electron transfer, which is dependent on solvent and temperature. Cyclic voltammetry measurements showed that addition of 2,2,2-trifluoroethanol (TFE) to a benzonitrile solution of the neutral radical induces a redox potential shift that is favorable for the spin-center transfer. Temperature-dependent cyclic voltammetry of the neutral radical using a novel low-temperature electrochemical cell demonstrated that the redox potentials change with decreasing temperature in a 199:1 CH2Cl2/TFE mixed solvent. Furthermore, theoretical calculation revealed that the energy levels of the frontier molecular orbitals involved in the spin-center transfer are lowered by the hydrogen-bonding interaction of TFE with the neutral radical. These results indicate that the hydrogen-bonding effect is a key factor for the occurrence of the spin-center transfer of TTF-linked 6-oxophenalenoxyl. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Veiga, Nicolás; Torres, Julia; González, Gabriel; Gómez, Kerman; Mansell, David; Freeman, Sally; Domínguez, Sixto; Kremer, Carlos
2011-02-01
Animal cells contain a pool of inositol phosphates whose biological function is still under current investigation. Ins(1,2,3) P3 is probably an important safe chelator of iron cations not strongly bound to proteins. In order to clarify its biological functions, Ins(1,2,3) P3 chemistry under physiological conditions must be completely elucidated. The protonation and complexation behaviour of Ins(1,2,3) P3 has been recently studied under these conditions by potentiometry. Under simulated physiological conditions it forms the protonated species H 2L 4- and H 3L 3-. The presence of high concentrations of potassium in intracellular compartments causes the formation of two predominant Ins(1,2,3) P3 complexes: [K(HL)] 4- and [K(H 2L)] 3-, in the absence of iron. In this work we expand part of this macroscopic knowledge to the inframolecular level, by 31P NMR measurements and focusing on the protonation and complexation of this biologically relevant molecule to potassium. We complete this study with theoretical calculations which lead us to predict the geometries of every form of the ligand and their relative stabilities. The influence of the ring conformation in protonated and complexed forms is also discussed.
Xu, Liang; Zhang, Dingfeng; Zhou, Yecheng; Zheng, Yusen; Cao, Liu; Jiang, Xiao-Fang; Lu, Fushen
2017-08-01
In this paper, mono- and di-4-N,N-bis(4-methoxylphenyl)aniline-substituted anthraquinone have been designed and synthesized through Suzuki reaction. For mono-4-N,N-bis(4-methoxylphenyl)aniline-substituted anthraquinone, polymorphous crystal structures have been obtained in different crystallization conditions. Electrochemical characterization combined with theoretical calculation suggests that the addition of a second triphenylamine unit causes a larger band gap with higher lying LUMO (Lowest Unoccupied Molecular Orbital) and HOMO (Highest Occupied Molecular Orbital). The linear optical property shows that the introduction of a second triphenylamine unit bring about a significant hyperchromic effect with the extinction coefficients increasing from 11199 M-1 cm-1 to 22136 M-1 cm-1. The third-order nonlinear optical properties indicate that the introduction of a second triphenylamine unit lead to a much larger nonlinear absorption coefficient and two-photon absorption cross section, with the relevant value increasing from 2.04 × 10-12 cm W-1 to 3.91 × 10-12 cm W-1, and from 148 GM to 286 GM, respectively.
Xie, Hua; Xing, Xiaopeng; Liu, Zhiling; Cong, Ran; Qin, Zhengbo; Wu, Xia; Tang, Zichao; Fan, Hongjun
2012-09-07
Structures and electronic properties of the mixed metal hydride anions AuAgH(-), Au(2)AgH(-), AuAg(2)H(-) and their neutrals are studied using anionic photoelectron imaging and theoretical calculations. The three isomers of AuAgH(-) are determined to be linear and those of AuAgH are determined to have C(s) symmetry. The structures of Au(2)AgH(-), AuAg(2)H(-) and their corresponding neutrals are determined to be planar with C(s) or C(2v) symmetries. The vertical detachment energies (VDEs) and adiabatic detachment energies (ADEs) of these anions are reported. Similar to the homonuclear Au(m)(-) and Ag(n)(-) clusters, the metal hydride anions with an even number of valence electrons have higher VDEs than those with an odd number. Variation of the VDEs of these metal hydride anions with interchange of Au, Ag and H (for example Au(m)Ag(n)(-)→ Au(m-1)Ag(n+ 1)(-), or Au(m-1)Ag(n)H(-)) will be shown to be characterized by the electronegativities of Au, Ag and H. The results presented in this study provide important insights into the similar and different characteristics of these three elements in small clusters.
GHB光学性质的DFT理论计算研究%The Study on the Optical Properties of GHB by DFT Theoretical Calculation
Institute of Scientific and Technical Information of China (English)
唐利斌; 宋立媛; 陈雪梅; 马钰; 庄继胜; 姬荣斌; 刘树平; 王忆锋; 叶婧; 台国安; 魏长松; 陆志文; 许扬羽
2011-01-01
The geometry optimization, IR spectrum, Raman spectrum, UV-Vis spectrum as well as frontier molecular orbitals are calculated by using Density Functional Theory (DFT) at B3LYP/6-31G level. Research results show that the theoretical calculation results agree well with experimental data, the characteristic peaks in IR, THz, UV-Vis and Raman spectra have been assigned. It is found that GHB has four obvious absorption peaks in 0.1~10THz range, they are located at 0.85, 2.89, 7.21 and 8.61 THz. GHB has three UV absorption peaks which located at 235.50, 190.23 and 169.79 nm, respectively. Based on the characteristic IR, Raman, THz, UV-Vis optical properties, GHB may be detected, identified, analyzed, and inspected by means of spectroscopic technique.%采用密度泛函理论( DFT)方法对γ-羟基丁酸(GHB)进行了B3LYP/6-31G水平上的分子结构优化、红外光谱、Raman光谱、紫外-可见光谱及分子前线轨道理论等计算.研究结果表明:理论计算结果与实验数据吻合得较好,对IR、THz、UV-Vis吸收光谱和Raman散射光谱中的特征峰进行了归属,发现GHB在0.1 ～ 10 THz波谱范围内有四个明显的吸收峰,分别位于0.85、2.89、7.21以及8.61 THz,GHB在紫外波段的235.50、190.23及169.79 nm有3个吸收峰.基于GHB具有特征性的IR、Raman、THz、UV-Vis光谱性质,可以使用光谱技术对GHB进行探测、识别、分析和检测.
Red Giant Oscillations: Stellar Models and Mode Frequency Calculations
DEFF Research Database (Denmark)
Jendreieck, A.; Weiss, A.; Aguirre, Victor Silva
2012-01-01
We present preliminary results on modelling KIC 7693833, the so far most metal-poor red-giant star observed by {\\it Kepler}. From time series spanning several months, global oscillation parameters and individual frequencies were obtained and compared to theoretical calculations. Evolution models ......_\\odot$ in radius and of about 2.5 Gyr in age....
Theoretical calculation of the photo electron angular distribution of neon%氖原子光电子角分布的理论计算∗
Institute of Scientific and Technical Information of China (English)
马堃; 颉录有; 张登红; 董晨钟; 屈一至
2016-01-01
The general formula of the angular distribution of photoelectron is derived by using the density matrix theory and Racah algebra method. For comparing with the experimental data, the general formula in this paper is matched to the parametric formula and the non-dipole parameters of the photoelectron angular distribution associated with the terms of the second order for both unpolarized and polarized incident light are given explicitly. From the formula of these parameters we can see that the contribution to the non-dipole parameter is from the interference between dipole amplitude and multipole amplitude. And then, the relativistic calculation program for photoelectron angular distribution is further developed with the help of the program packages GRASP2K and RATIP which are based on the multi-configuration Dirac-Fock method. By using this program, the dipole and non-dipole angular-distribution parameters for neon 2s and 2p photoelectrons are calculated concretely. The good agreement between the results of this paper and the available theoretical data is obtained in a 50–5000 eV photoelectron-energy range studied. On this basis, the angular photoelectron distributions for neon 2s and 2p are calculated with and without considering the second non-dipole terms at the photoelectron energy E = 600 eV and E = 5000 eV, respectively. Special attention is paid to the effects of the polarization property of incident light and the non-dipole terms of photo-electron interaction on the angular distribution of photoelectrons. The results show that 1) the dipole and non-dipole parameters of the photoelectron angular distribution are sensitive to the ionized electron orbital, it can bring out considerable diversities among the photoelectron angular distributions of the different shells;2) non-dipole effects make the photoelectron forward distribution in the direction of incident light, the polarization property of incident light will strengthen the asymmetric distribution of
Energy Technology Data Exchange (ETDEWEB)
Mein, S [Duke University Medical Physics Graduate Program (United States); Gunasingha, R [Department of Radiation Safety, Duke University Medical Center (United States); Nolan, M [Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University (United States); Oldham, M; Adamson, J [Department of Radiation Oncology, Duke University Medical Center (United States)
2016-06-15
Purpose: X-PACT is an experimental cancer therapy where kV x-rays are used to photo-activate anti-cancer therapeutics through phosphor intermediaries (phosphors that absorb x-rays and re-radiate as UV light). Clinical trials in pet dogs are currently underway (NC State College of Veterinary Medicine) and an essential component is the ability to model the kV dose in these dogs. Here we report the commissioning and characterization of a Monte Carlo (MC) treatment planning simulation tool to calculate X-PACT radiation doses in canine trials. Methods: FLUKA multi-particle MC simulation package was used to simulate a standard X-PACT radiation treatment beam of 80kVp with the Varian OBI x-ray source geometry. The beam quality was verified by comparing measured and simulated attenuation of the beam by various thicknesses of aluminum (2–4.6 mm) under narrow beam conditions (HVL). The beam parameters at commissioning were then corroborated using MC, characterized and verified with empirically collected commissioning data, including: percent depth dose curves (PDD), back-scatter factors (BSF), collimator scatter factor(s), and heel effect, etc. All simulations were conducted for N=30M histories at M=100 iterations. Results: HVL and PDD simulation data agreed with an average percent error of 2.42%±0.33 and 6.03%±1.58, respectively. The mean square error (MSE) values for HVL and PDD (0.07% and 0.50%) were low, as expected; however, longer simulations are required to validate convergence to the expected values. Qualitatively, pre- and post-filtration source spectra matched well with 80kVp references generated via SPEKTR software. Further validation of commissioning data simulation is underway in preparation for first-time 3D dose calculations with canine CBCT data. Conclusion: We have prepared a Monte Carlo simulation capable of accurate dose calculation for use with ongoing X-PACT canine clinical trials. Preliminary results show good agreement with measured data and hold
Abuzariba, Suad Mohamed
This thesis includes a theoretical study of the performance of an optical network system with linear impairments: chromatic dispersion (CD), polarization mode dispersion (PMD), polarization dependent loss (PDL), and amplified spontaneous emission (ASE) noise. Both the a-factor and bit error rate (BER) were used as performance parameters in this study. First, an analytical optical eye diagram evaluation for a system of highly mode coupled PMD/PDL fiber and lumped sections (up to fifteen sections) have been presented in this study. Based on this evaluation we found that with PDL considered as well as PMD, the a-factor of the output becomes higher than that of a Maxwellian fiber having the same total root mean-squared PMD and PDL values, when the mean-square PDL element of the lumped sections makes up the major portion of the total mean-square of the whole system. Whereas without considering PDL, the a-factor becomes higher as the mean-square PMD element of the Maxwellian fiber takes the major portion of the total mean-square PMD element of the whole system. Also the worst case for the a-factor occurred when the lumped sections were in the middle between two equivalent Maxwellian fibers, rether than if the lumped sections were followed by Maxwellian fiber or the Maxwellian fiber is followed by the lumped sections. We also note that two equivalent Maxwellian fibers connected in series will not give the same a-factor as a Maxwellian fiber equivalent calculated by concatenation rules unless they have the same values of PMD, PDL, and polarization direction correlation elements. Second, considering ASE-noise besides CD, PMD, and PDL, improved values of bit error rate (BER) were gotten using the moment generation function for the optical system in cases of ON-OFF modulation format and DPSK modulation format. We found that, even when considering the noise only without the signal, the probability density function of the output current was dependent on the output state of
Al-Jaroudi, Said S; Altaf, Muhammad; Al-Saadi, Abdulaziz A; Kawde, Abdel-Nasser; Altuwaijri, Saleh; Ahmad, Saeed; Isab, Anvarhusein A
2015-10-01
The gold(III) complexes of the type (1,2-diaminocyclohexane)(1,3-diaminopropane)gold(III) chloride, [(DACH)Au(pn)]Cl3, [where DACH = cis-, trans-1,2- and S,S-1,2-diaminocyclohexane and pn = 1,3-diaminopropane] have been synthesized and characterized using various spectroscopic and analytical techniques including elemental analysis, UV-Vis and FTIR spectroscopy; solution as well as solid-state NMR measurements. The solid-state (13)C NMR shows that 1,2-diaminocyclohexane (1,2-DACH) and 1,3-diaminopropane (pn) are strongly bound to the gold(III) center via N donor atoms. The stability of the mixed diamine ligand gold(III) was checked by UV-Vis spectroscopy and NMR measurements. The molecular structure of compound 1 (containing cis-1,2-DACH) was determined by X-ray diffraction analysis. The structure of 1 consists of [(cis-DACH)Au(pn)](3+) complex ion and chloride counter ions. Each gold atom in the complex ion adopts a distorted square-planar geometry. The structural details and relative stabilities of the four possible isomers of the complexes were also estimated at the B3LYP/LANL2DZ level of theoretical calculations. The computational study demonstrates that trans- conformations are slightly more stable than the cis- conformations. The antiproliferative effects and cytotoxic properties of the mixed ligand gold(III) complexes were evaluated in vitro on human gastric SGC7901 and prostate PC3 cancer cells using MTT assay. The antiproliferative study of the gold(III) complexes on PC3 and SGC7901 cells indicate that complex 3 (containing 1S,2S-(+)-1,2-(DACH)) is the most effective antiproliferative agent. The IC50 data reveal that the in vitro cytotoxicity of complex 3 against SGC7901 cancer cells manifested similar and very pronounced cytotoxic effects with respect to cisplatin. Moreover, the electrochemical behavior, and the interaction of complex 3 with two well-known model proteins, namely, hen egg white lysozyme and bovine serum albumin is also reported.
Energy Technology Data Exchange (ETDEWEB)
Marc Vanderhaeghen
2007-04-01
The theoretical issues in the interpretation of the precision measurements of the nucleon-to-Delta transition by means of electromagnetic probes are highlighted. The results of these measurements are confronted with the state-of-the-art calculations based on chiral effective-field theories (EFT), lattice QCD, large-Nc relations, perturbative QCD, and QCD-inspired models. The link of the nucleon-to-Delta form factors to generalized parton distributions (GPDs) is also discussed.
Prakash, Punit; Salgaonkar, Vasant A.; Scott, Serena J.; Jones, Peter; Hensley, Daniel; Holbrook, Andrew; Plata, Juan; Sommer, Graham; Diederich, Chris J.
2013-02-01
Image-guided thermal interventions have been proposed for potential palliative and curative treatments of pancreatic tumors. Catheter-based ultrasound devices offer the potential for temporal and 3D spatial control of the energy deposition profile. The objective of this study was to apply theoretical and experimental techniques to investigate the feasibility of endogastric, intraluminal and transgastric catheter-based ultrasound for MR guided thermal therapy of pancreatic tumors. The transgastric approach involves insertion of a catheter-based ultrasound applicator (array of 1.5 mm OD x 10 mm transducers, 360° or sectored 180°, ~7 MHz frequency, 13-14G cooling catheter) directly into the pancreas, either endoscopically or via image-guided percutaneous placement. An intraluminal applicator, of a more flexible but similar construct, was considered for endoscopic insertion directly into the pancreatic or biliary duct. An endoluminal approach was devised based on an ultrasound transducer assembly (tubular, planar, curvilinear) enclosed in a cooling balloon which is endoscopically positioned within the stomach or duodenum, adjacent to pancreatic targets from within the GI tract. A 3D acoustic bio-thermal model was implemented to calculate acoustic energy distributions and used a FEM solver to determine the transient temperature and thermal dose profiles in tissue during heating. These models were used to determine transducer parameters and delivery strategies and to study the feasibility of ablating 1-3 cm diameter tumors located 2-10 mm deep in the pancreas, while thermally sparing the stomach wall. Heterogeneous acoustic and thermal properties were incorporated, including approximations for tumor desmoplasia and dynamic changes during heating. A series of anatomic models based on imaging scans of representative patients were used to investigate the three approaches. Proof of concept (POC) endogastric and transgastric applicators were fabricated and experimentally
Liu, Gang; Mei, Yang; Zhang, Xin-Xin; Zheng, Wen-Chen
2015-05-01
The high-order perturbation formulas based on a two-mechanism model (where in addition to the contributions from the crystal-field (CF) mechanism in the usually-applied CF theory, those from the generally-neglected charge-transfer (CT) mechanism are also contained) are employed to calculate the spin-Hamiltonian parameters (g factors g//, g⊥ and the hyperfine structure constants A//, A⊥) of the square planar CuCl4 2 - clusters in Cs2ZrCl6 crystal. The needed CF energy levels in the calculations are obtained from the observed optical spectra. The calculated results show reasonable agreement with the experimented values. The negative sign of A// and positive sign of A⊥ are proposed from the calculations. The calculations also suggest that one should take account of the contributions due to both the CF and CT mechanisms for the exact and rational calculations of spin-Hamiltonian parameters of Cu2+-Cl- combination in crystals.
Energy Technology Data Exchange (ETDEWEB)
Talbi, D [Universite Montpellier II - GRAAL, CNRS - UMR 5024, place Eugene Bataillon, 34095 Montpellier (France); Hickman, A P; Kashinski, D; Malenda, R F [Department of Physics, Lehigh University, 16 Memorial Dr. E, Bethlehem, PA, 18015 (United States); Redondo, P, E-mail: Dahbia.Talbi@graal.univ-montp2.f, E-mail: aph2@lehigh.ed [Departamento de Quimica Fisica, Facultad de Ciencias, Universidad de Valladolid, 47005 Valladolid (Spain)
2009-11-15
Preliminary calculations related to the dissociative recombination (DR) of electrons with C{sub 3}H{sup +}{sub 3} have been carried out. Both the linear and cyclic isomers of this ion exist in the interstellar medium, and accurate DR rate constants for both isomers are needed for astrophysical models. The electronic structure calculations reported here yield quasi-diabatic potential energy curves that can be used to assess the efficiency of dissociation of a CH bond. The calculations confirm a favorable position of a dissociative state for the cyclic isomer and suggest that dissociation of the linear isomer is less probable. More detailed dynamical studies are planned, and a normal mode analysis of the vibrational modes of C{sub 3}H{sup +}{sub 3} is reported as the first step in that direction.
Borque-Fernando, Á; Esteban-Escaño, L M; Rubio-Briones, J; Lou-Mercadé, A C; García-Ruiz, R; Tejero-Sánchez, A; Muñoz-Rivero, M V; Cabañuz-Plo, T; Alfaro-Torres, J; Marquina-Ibáñez, I M; Hakim-Alonso, S; Mejía-Urbáez, E; Gil-Fabra, J; Gil-Martínez, P; Ávarez-Alegret, R; Sanz, G; Gil-Sanz, M J
2016-04-01
To prevent the overdiagnosis and overtreatment of prostate cancer (PC), therapeutic strategies have been established such as active surveillance and focal therapy, as well as methods for clarifying the diagnosis of high-grade prostate cancer (HGPC) (defined as a Gleason score ≥7), such as multiparametric magnetic resonance imaging and new markers such as the 4Kscore test (4KsT). By means of a pilot study, we aim to test the ability of the 4KsT to identify HGPC in prostate biopsies (Bx) and compare the test with other multivariate prognostic models such as the Prostate Cancer Prevention Trial Risk Calculator 2.0 (PCPTRC 2.0) and the European Research Screening Prostate Cancer Risk Calculator 4 (ERSPC-RC 4). Fifty-one patients underwent a prostate Bx according to standard clinical practice, with a minimum of 10 cores. The diagnosis of HGPC was agreed upon by 4 uropathologists. We compared the predictions from the various models by using the Mann-Whitney U test, area under the ROC curve (AUC) (DeLong test), probability density function (PDF), box plots and clinical utility curves. Forty-three percent of the patients had PC, and 23.5% had HGPC. The medians of probability for the 4KsT, PCPTRC 2.0 and ERSPC-RC 4 were significantly different between the patients with HGPC and those without HGPC (p≤.022) and were more differentiated in the case of 4KsT (51.5% for HGPC [25-75 percentile: 25-80.5%] vs. 16% [P 25-75: 8-26.5%] for non-HGPC; p=.002). All models presented AUCs above 0.7, with no significant differences between any of them and 4KsT (p≥.20). The PDF and box plots showed good discriminative ability, especially in the ERSPC-RC 4 and 4KsT models. The utility curves showed how a cutoff of 9% for 4KsT identified all cases of HGPC and provided a 22% savings in biopsies, which is similar to what occurs with the ERSPC-RC 4 models and a cutoff of 3%. The assessed predictive models offer good discriminative ability for HGPCs in Bx. The 4KsT is a good classification
Energy Technology Data Exchange (ETDEWEB)
Malenda, R. F.; Price, T. J.; Stevens, J.; Uppalapati, S. L.; Fragale, A.; Weiser, P. M.; Kuczala, A.; Hickman, A. P., E-mail: aph2@lehigh.edu [Department of Physics, Lehigh University, 16 Memorial Dr. East, Bethlehem, Pennsylvania 18015 (United States); Talbi, D. [Laboratoire Univers et Particules de Montpellier, UMR 5299, Université Montpellier, Place Eugène Bataillon, 34095 Montpellier (France)
2015-06-14
We have performed extensive calculations to investigate thermal energy, rotationally inelastic collisions of NaK (A{sup 1}Σ{sup +}) with He. We determined a potential energy surface using a multi-reference configuration interaction wave function as implemented by the GAMESS electronic structure code, and we have performed coupled channel scattering calculations using the Arthurs and Dalgarno formalism. We also calculate the Grawert coefficients B{sub λ}(j, j′) for each j → j′ transition. These coefficients are used to determine the probability that orientation and alignment are preserved in collisions taking place in a cell environment. The calculations include all rotational levels with j or j′ between 0 and 50, and total (translational and rotational) energies in the range 0.0002–0.0025 a.u. (∼44–550 cm{sup −1}). The calculated cross sections for transitions with even values of Δj tend to be larger than those for transitions with odd Δj, in agreement with the recent experiments of Wolfe et al. (J. Chem. Phys. 134, 174301 (2011)). The calculations of the energy dependence of the cross sections and the calculations of the fraction of orientation and alignment preserved in collisions also exhibit distinctly different behaviors for odd and even values of Δj. The calculations also indicate that the average fraction of orientation or alignment preserved in a transition becomes larger as j increases. We interpret this behavior using the semiclassical model of Derouard, which also leads to a simple way of visualizing the distribution of the angles between the initial and final angular momentum vectors j and j′. Finally, we compare the exact quantum results for j → j′ transitions with results based on the simpler, energy sudden approximation. That approximation is shown to be quite accurate.
Energy Technology Data Exchange (ETDEWEB)
Manning, Karessa L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dolislager, Fredrick G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Bellamy, Michael B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
2016-11-01
The Preliminary Remediation Goal (PRG) and Dose Compliance Concentration (DCC) calculators are screening level tools that set forth Environmental Protection Agency's (EPA) recommended approaches, based upon currently available information with respect to risk assessment, for response actions at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) sites, commonly known as Superfund. The screening levels derived by the PRG and DCC calculators are used to identify isotopes contributing the highest risk and dose as well as establish preliminary remediation goals. Each calculator has a residential gardening scenario and subsistence farmer exposure scenarios that require modeling of the transfer of contaminants from soil and water into various types of biota (crops and animal products). New publications of human intake rates of biota; farm animal intakes of water, soil, and fodder; and soil to plant interactions require updates be implemented into the PRG and DCC exposure scenarios. Recent improvements have been made in the biota modeling for these calculators, including newly derived biota intake rates, more comprehensive soil mass loading factors (MLFs), and more comprehensive soil to tissue transfer factors (TFs) for animals and soil to plant transfer factors (BV's). New biota have been added in both the produce and animal products categories that greatly improve the accuracy and utility of the PRG and DCC calculators and encompass greater geographic diversity on a national and international scale.
Energy Technology Data Exchange (ETDEWEB)
S.G. Lee; J.G. Bak; Y.S. Jung; M. Bitter; K.W. Hill; G. Hoelzer; O. Wehrhan; E. Foerster
2003-04-09
This paper describes a new method for the simultaneous measurement of the integrated reflectivity of a crystal for multiple orders of reflection at a predefined Bragg angle. The technique is demonstrated with a mica crystal for Bragg angles of 43{sup o}, 47{sup o}, and 50{sup o}. The measured integrated reflectivity for Bragg reflections up to the 24th order is compared with new theoretical predictions, which are also presented in this paper.
Afaneh, Akef T; Schreckenbach, Georg; Wang, Feiyue
2014-09-25
The structures and harmonic vibrational frequencies of water clusters (H2O)n, n = 1-10, have been computed using the M06-L/, B3LYP/, and CAM-BLYP/cc-pVTZ levels of theories. On the basis of the literature and our results, we use three hexamer structures of the water molecules to calculate an estimated "experimental" average solvation free energy of [Hg(H2O)6](2+). Aqueous formation constants (log K) for Hg(2+) complexes, [Hg(L)m(H2O)n](2-mq), L = Cl(-), HO(-), HS(-), and S(2-), are calculated using a combination of experimental (solvation free energies of ligands and Hg(2+)) and calculated gas- and liquid-phase free energies. A combined approach has been used that involves attaching n explicit water molecules to the Hg(2+) complexes such that the first coordination sphere is complete, then surrounding the resulting (Hg(2+)-Lm)-(OH2)n cluster by a dielectric continuum, and using suitable thermodynamic cycles. This procedure significantly improves the agreement between the calculated log K values and experiment. Thus, for some neutral and anionic Hg(II) complexes, particularly Hg(II) metal ion surrounded with homo- or heteroatoms, augmenting implicit solvent calculations with sufficient explicit water molecules to complete the first coordination sphere is required-and adequate-to account for strong short-range hydrogen bonding interactions between the anion and the solvent. Calculated values for formation constants of Hg(2+) complexes with S(2-) and SH(-) are proposed. Experimental measurements of these log K values have been lacking or controversial.
Institute of Scientific and Technical Information of China (English)
葛自明; 周雅君; 吕志伟; 王治文
2002-01-01
The triple differential cross sections of the 2p electron of argon in a coplanar highly asymmetric geometry have beencalculated with the modified distorted wave Born approximation (DWBA) and the target Hartree-Fock approximationmethods. The damping polarization of the semi-classical short-range potentials and the Mee factor are included in thedistorting potentials of the modified DWBA. Theoretical results are compared with a recent experiment. The dynamicmechanism of inner shell ionization in a coplanar highly asymmetric geometry (e, 2e) reaction are also discussed.
Yaqoob, M.A.; Rooij, de M.B.; Schipper, D.J.
2013-01-01
The adhesion force due to capillary interaction between two hydrophilic surfaces is strongly dependent on the partial pressure of water and is often calculated using the Kelvin equation. The validity of the Kelvin equation is questionable at low relative humidity (RH) of water, like in high vacuum a
Shin-ya, Kei; Takahashi, Osamu; Katsumoto, Yukiteru; Ohno, Keiichi
2007-02-01
Contributions of the intramolecular CH⋯π and CH⋯O interactions to the molecular conformation of benzyl methyl ether (BME) have been investigated by matrix-isolation infrared (IR) spectroscopy combined with quantum chemical calculations. Comparative investigations have been carried out for propylbenzene. Quantum chemical calculations predict that there are two conformers for BME; for the ET conformer the methyl ether and the phenyl groups lie in the plane of the benzene ring, while for the AG conformer they are out of the plane. Comparison between the observed and calculated spectra for BME reveals that the ET and AG conformers coexist in an Ar matrix. By measuring matrix-isolation IR spectra of BME deposited at different gas temperatures, the enthalpy difference (Δ H (AG - ET)) between ET and AG conformers was determined to be -1.03 ± 0.06 kJ mol -1. The experimental and calculation results indicate that the AG conformer of BME is stabilized by the intramolecular CH⋯π and CH⋯O interactions.
Directory of Open Access Journals (Sweden)
Guangtao Zhang
2017-05-01
Full Text Available Inter-turn short circuit of field windings (ISCFW may cause the field current of a generator to increase, output reactive power to decrease, and unit vibration to intensify, seriously affecting its safe and stable operation. Full integration of mechanical and electrical characteristics can improve the sensitivity of online monitoring, and detect the early embryonic period fault of small turns. This paper studies the calculations and variations of unbalanced magnetic pull (UMP, of which the excitation source of rotor vibration is the basis and key to online fault monitoring. In grid load operation, ISCFW are first calculated with the multi-loop method, so as to obtain the numerical solutions of the stator and the rotor currents during the fault. Next, the air-gap magnetic field of the ISCFW is analyzed according to the actual composition modes of the motor loops in the fault, so as to obtain the analytic expressions of the air-gap magnetic motive force (MMF and magnetic density. The UMP of the rotor is obtained by solving the integral of the Maxwell stress. The correctness of the electric quantity calculation is verified by the ISCFW experiment, conducted in a one pair-pole non-salient pole model machine. On this basis, comparing the simulation analysis with the calculation results of the model in this paper not only verifies the accuracy of the electromagnetic force calculation, but also proves that the latter has the advantages of a short time consumption and high efficiency. Finally, the influencing factors and variation law of UMP are analyzed by means of an analytic model. This develops a base for the online monitoring of ISCFW with the integration of mechanical and electrical information.
Institute of Scientific and Technical Information of China (English)
QUO,Hui; ZHU,Hai-Yan; HE,Xian-Ling; SU,Zhen-Ping; LI,Jun; ZHANG,Feng-Xing
2007-01-01
Two supramolecular complexes [Zn(tacd)2](C6H8O4)·6H2O (1) and [Cu(tacd)2]Cl2·4H2O (2) were synthesized and characterized by elemental analysis, IR spectra, TGA and single-crystal X-ray diffraction analysis. The crystal structure showed that the metal ions in complexes 1 and 2 had similar coordination circumstance. But for the complex 2, it formed a novel two-dimensional supramolecular network with 12-membered rings and four-membered rings via hydrogen bond interaction. The thermal gravimetric analyses indicated that the two complexes had similar steps of weight-loss. On the basis of experiment, the two complexes were calculated by DFT-B3LYP/6-31G(d) in Gaussian 03. The results of calculation are in good agreement with the experiment.
Maffeo, Davide; Lampropoulou, Maria; Fardis, Michael; Lazarou, Yannis G; Mavridis, Irene M; Mavridou, Despoina A I; Urso, Elena; Pratsinis, Harris; Kletsas, Dimitris; Yannakopoulou, Konstantina
2010-04-21
Novel -type cyclodextrin (CD) derivatives, , and , bearing 6, 7 and 8 bis(carboxymethyl)amino (iminodiacetic acid) groups, respectively, were prepared, and their complexation with Eu(iii), Tb(iii) and Gd(iii) ions was studied. Luminescence titrations and mass spectrometry showed formation of multimetal complexes ( 2 to 3, mainly 3 and exactly 4 metal ions), whereas luminescence lifetime measurements revealed the presence of exchangeable water molecules. Semiempirical quantum mechanical calculations, performed by the PM3 method and assessed by DFT calculations on model ligands, indicated efficient multi-metal complexation, in agreement with the experiment. The structures showed coordination of the metal ions in the outer primary side of the CDs via 4 carboxylate O atoms, 2 N atoms and a glucopyranose O atom per metal ion. Coordination of water molecules was also predicted, in accordance with experimental results. Calculated bond lengths and angles were in agreement with literature experimental values of lanthanide complexes. Calculated energies showed that complex stability decreases in the order > > . (1)H NMR molecular relaxivity measurements for the Gd(iii) complexes of , or in water afforded values 4 to 10 times higher than the relaxivity of a commercial contrast agent at 12 MHz, and 6 to 20 times higher at 100 MHz. Solutions of and Gd(iii) complexes in human blood plasma displayed relaxivity values at 100 MHz 7 and 12 times, respectively, higher than the commercial agent. MTT tests of the Gd(iii) complexes using human skin fibroblasts did not show toxicity. Attempts to supramolecularly sensitize the luminescence of the lanthanide complexes using various aromatic CD guests were ineffective, evidently due to large guest-metal distances and inefficient inclusion. The described lanthanide complexes, could be useful as contrast agents in MRI.
Directory of Open Access Journals (Sweden)
Alejandro Morales-Bayuelo
2014-01-01
Full Text Available A theoretical study on the molecular polarization of thiophene and furan under the action of an electric field using Local Quantum Similarity Indexes (LQSI was performed. This model is based on Hirshfeld partitioning of electron density within the framework of Density Functional Theory (DFT. Six local similarity indexes were used: overlap, overlap-interaction, coulomb, coulomb-interaction, Euclidian distances of overlap, and Euclidean distances of coulomb. In addition Topo-Geometrical Superposition Algorithm (TGSA was used as a method of alignment. This method provides a straightforward procedure to solve the problem of molecular relative orientation. It provides a tool to evaluate molecular quantum similarity, enabling the study of structural systems, which differ in only one atom such as thiophene and furan (point group C2v and cyclopentadienyl molecule (point group D5h. Additionally, this model can contribute to the interpretation of chemical bonds, and molecular interactions in the framework of the solvent effect theory.
Zehe, Michael J.; Jaffe, Richard L.
2010-01-01
High-level ab initio calculations have been performed on the exo and endo isomers of gas-phase tetrahydrodicyclopentadiene (THDCPD), a principal component of the jet fuel JP10, using the Gaussian Gx and Gx(MPx) composite methods, as well as the CBS-QB3 method, and using a variety of isodesmic and homodesmotic reaction schemes. The impetus for this work is to help resolve large discrepancies existing between literature measurements of the formation enthalpy Delta (sub f)H deg (298) for exo-THDCPD. We find that use of the isodesmic bond separation reaction C10H16 + 14CH4 yields 12C2H6 yields results for the exo isomer (JP10) in between the two experimentally accepted values, for the composite methods G3(MP2), G3(MP2)//B3LYP, and CBS-QB3. Application of this same isodesmic bond separation scheme to gas-phase adamantane yields a value for Delta (sub f)H deg (298) within 5 kJ/mol of experiment. Isodesmic bond separation calculations for the endo isomer give a heat of formation in excellent agreement with the experimental measurement. Combining our calculated values for the gas-phase heat of formation with recent measurements of the heat of vaporization yields recommended values for Delta (sub f)H deg (298)liq of -126.4 and -114.7 kJ/mol for the exo and endo isomers, respectively.
Sheu, Hong-Li; Kim, Sunghwan; Laane, Jaan
2014-01-01
The infrared and Raman spectra of 2,6-difluoropyridine (26DFPy) along with ab initio and DFT computations have been used to assign the vibrations of the molecule in its S0 electronic ground state and to calculate its structure. The ultraviolet absorption spectrum showed the electronic transition to the S1(π,π*) state to be at 37,820.2 cm−1. With the aid of ab initio computations the vibrational frequencies for this excited state were also determined. TD-B3LYP and CASSCF computations for the excited states were carried out to calculate the structures for the S1(π,π*) and S2(n,π*) excited states. The CASSCF results predict that the S1(π,π*) state is planar and the S2(n,π*) state has a barrier to planarity of 256 cm−1. The TD-B3LYP computations predict a barrier of 124 cm−1 for the S1(π,π*) states, but the experimental results support the planar structure. Hypothetical models for the ring-puckering potential energy function were calculated for both electronic excited states to show the predicted quantum states. The changes in the vibrational frequencies in the two excited states reflect the weaker π bonding within the pyridine ring. PMID:24070189
Samsonowicz, M.; Kowczyk-Sadowy, M.; Piekut, J.; Regulska, E.; Lewandowski, W.
2016-04-01
The structural and vibrational properties of lithium, sodium, potassium, rubidium and cesium homovanillates were investigated in this paper. Supplementary molecular spectroscopic methods such as: FT-IR, FT-Raman in the solid phase, UV and NMR were applied. The geometrical parameters and energies were obtained from density functional theory (DFT) B3LYP method with 6-311++G** basis set calculations. The geometry of the molecule was fully optimized, vibrational spectra were calculated and fundamental vibrations were assigned. Geometric and magnetic aromaticity indices, atomic charges, dipole moments, HOMO and LUMO energies were also calculated. The microbial activity of investigated compounds was tested against Bacillus subtilis (BS), Pseudomonas aeruginosa (PA), Escherichia coli (EC), Staphylococcus aureus (SA) and Candida albicans (CA). The relationship between the molecular structure of tested compounds and their antimicrobial activity was studied. The principal component analysis (PCA) was applied in order to attempt to distinguish the biological activities of these compounds according to selected band wavenumbers. Obtained data show that the FT-IR spectra can be a rapid and reliable analytical tool and a good source of information for the quantitative analysis of the relationship between the molecular structure of the compound and its biological activity.
Imachi, Hiroto; Yokoyama, Seiya; Kaji, Takami; Abe, Yukiya; Tada, Tomofumi; Hoshi, Takeo
2016-12-01
One-hundred-nm-scale electronic structure calculations were carried out on the K supercomputer by our original simulation code ELSES (http://www.elses.jp/) The present paper reports preliminary results of transport calculations for condensed organic polymers. Large-scale calculations are realized by novel massively parallel order-N algorithms. The transport calculations were carried out as a theoretical extension for the quantum wavepacket dynamics simulation. The method was applied to a single polymer chain and condensed polymers.
Zhang, Shufang; Zhang, Xiaoyan; Tang, Ke; Zhou, Zhengyu
2009-08-15
The dissociation constant of 1,2,3,9-tetrahydro-4H-carbazol-4-one was determined by ultraviolet absorption spectrometry method based on the absorption spectra of 1,2,3,9-tetrahydro-4H-carbazol-4-one at different pH in ethanol-water mixed solvents. The results show that the pK(b) was a good linear function of the volume fraction of ethanol in the concentration range studied. The dissociation constant of 1, 2, 3,9-tetrahydro-4H-carbazol-4-one in water were determined by extrapolation to be 14.04 under the condition of this experiment. The accurate pK(b) calculations of 1,2,3,9-tetrahydro-4H-carbazol-4-one have been investigated using the combination of the extended clusters-continuum model with the polarizable continuum solvation model (PCM). The calculations are performed at the B3LYP/6-31G levels. The formation of molecular clusters by means of the 1,2,3,9-tetrahydro-4H-carbazol-4-one wrapped up with water molecules leads to the weakness of the interaction between the polar solvents and the 1,2,3,9-tetrahydro-4H-carbazol-4-one, hence, the accuracy of pK(b) has been enhanced. The dissociation constant of 1,2,3,9-tetrahydro-4H-carbazol-4-one in water were calculated to be 14.10 and agreed well with experimental data.
Karthikeyan, N; Joseph Prince, J; Ramalingam, S; Periandy, S
2015-05-15
In the present research work, the FT-IR, FT-Raman and (13)C and (1)H NMR spectra of the α-Methylstyrene were recorded. The observed fundamental frequencies in finger print as well as functional group regions were assigned according to their uniqueness region. The Gaussian computational calculations are carried out by HF and DFT (B3LYP and B3PW91) methods with 6-31++G(d,p) and 6-311++G(d,p) basis sets and the corresponding results were tabulated. The impact of the presence of vinyl group in phenyl structure of the compound is investigated. The modified vibrational pattern of the molecule associated vinyl group was analyzed. Moreover, (13)C NMR and (1)H NMR were calculated by using the gauge independent atomic orbital (GIAO) method with B3LYP methods and the 6-311++G(d,p) basis set and their spectra were simulated and the chemical shifts linked to TMS were compared. A study on the electronic and optical properties; absorption wavelengths, excitation energy, dipole moment and frontier molecular orbital energies were carried out. The kubo gap of the present compound was calculated related to HOMO and LUMO energies which confirm the occurring of charge transformation between the base and ligand. Besides frontier molecular orbitals (FMO), molecular electrostatic potential (MEP) was performed. The NLO properties related to Polarizability and hyperpolarizability based on the finite-field approach were also discussed. Crown Copyright © 2015. Published by Elsevier B.V. All rights reserved.
Walters, Wendell W.; Michalski, Greg
2016-10-01
The oxygen stable isotope composition (δ18O) of nitrogen oxides [NOx = nitric oxide (NO) + nitrogen dioxide (NO2)] and their oxidation products (NOy = NOx + nitric acid (HNO3) + particulate nitrate (p-NO3-) + nitrate radical (NO3) + dinitrogen pentoxide (N2O5) + nitrous acid (HONO) + …) have been shown to be a useful tool for inferring the proportion of NOx that is oxidized by ozone (O3). However, isotopic fractionation processes may have an influence on δ18O of various NOy molecules and other atmospheric O-bearing molecules pertinent to NOx oxidation chemistry. Here we have evaluated the impacts of O isotopic exchange involving NOy molecules, the hydroxyl radical (radOH), and water (H2O) using reduced partition function ratios (xβ) calculated by hybrid density functional theory. Assuming atmospheric isotopic equilibrium is achieved between NO and NO2 during the daytime, and NO2, NO3, and N2O5 during the nighttime, δ18O-δ15N compositions were predicted for the major atmospheric nitrate formation pathways using our calculated exchange fractionation factors and isotopic mass-balance. Our equilibrium model predicts that various atmospheric nitrate formation pathways, including NO2 + radOH → HNO3, N2O5 + H2O + surface → 2HNO3, and NO3 + R → HNO3 + Rrad will yield distinctive δ18O-δ15N compositions. Our calculated δ18O-δ15N compositions match well with previous atmospheric nitrate measurements, and will potentially help better understand the role oxidation chemistry plays on the N and O isotopic composition of atmospheric nitrate.
Institute of Scientific and Technical Information of China (English)
刘丽梅; 杨林; 夏建才
2011-01-01
The explosion temperature of expanded ammonium nitrate explosives are calculated in this paper. The result shows that the explosion temperature of opencast expanded ammonium nitrate explosives, rock expanded ammonium nitrate explosives, class Ⅰ and Ⅱ coal mine permissible expanded ammonium nitrate explosives is 2 722 K, 2 771 K,2 544 K,2 486 K respectively. The explosion temperature of rock expanded ammonium nitrate explosives in assumed formula are calculated when the ratio of paraffin with diesel oil in composite fuel oil are different. According to the calculation results,it can be seen that the explosion heat and explosion temperature of rock expanded ammonium nitrate explosives increase weakly with the increasing of contents of paraffin in composite fuel oil.%运用B-W法确定膨化硝铵炸药的爆炸反应方程式,用盖斯定律计算定容爆热,用加权法计算爆炸产物的摩尔定容热容,研究计算得出露天膨化硝铵炸药、岩石膨化硝铵炸药、一级、二级煤矿许用膨化硝铵炸药的爆温依次为2722 K、2 771K、2544K和2 486 K.同时计算分析了复合油相中不同的石蜡与柴油的混合比例对岩石膨化硝铵炸药爆热、爆温数据的影响情况,计算结果表明复合油相组成的变化对岩石膨化硝铵炸药爆热、爆温的影响不明显.
Institute of Scientific and Technical Information of China (English)
Shen Guang-Xian; Linghu Rong-Feng; Wang Rong-Kai; Yang Xiang-Dong
2007-01-01
In this paper, close-coupling method was applied to the He-H2(D2,T2) system, and the first vibrational excitation differences of these partial wave cross sections, this paper have obtained the change rules of the partial wave cross sections with increases of quantum number, and with change of reduced mass of system. Based on the calculation,influence on the partial wave cross sections brought by the variations in the reduced mass of systems and in the relative kinetic energy of incident atoms is discussed.
Energy Technology Data Exchange (ETDEWEB)
Kostko, Oleg; Zhou, Jia; Sun, Bian Jian; Lie, Jie Shiuan; Chang, Agnes H.H.; Kaiser, Ralf I.; Ahmed, Musahid
2010-06-10
Results from single photon vacuum ultraviolet photoionization of astrophysically relevant CnN clusters, n = 4 - 12, in the photon energy range of 8.0 eV to 12.8 eV are presented. The experimental photoionization efficiency curves, combined with electronic structure calculations, provide improved ionization energies of the CnN species. A search through numerous nitrogen-terminated CnN isomers for n=4-9 indicates that the linear isomer has the lowest energy, and therefore should be the most abundant isomer in the molecular beam. Comparison with calculated results also shed light on the energetics of the linear CnN clusters, particularly in the trends of the even-carbon and the odd-carbon series. These results can help guide the search of potential astronomical observations of these neutral molecules together with their cations in highly ionized regions or regions with a high UV/VUV photon flux (ranging from the visible to VUV with flux maxima in the Lyman- region) in the interstellar medium.
Energy Technology Data Exchange (ETDEWEB)
Kostko, Oleg; Zhou, Jia; Sun, Bian Jian; Lie, Jie Shiuan; Chang, Agnes H.H.; Kaiser, Ralf I.; Ahmed, Musahid
2010-03-02
Results from single photon vacuum ultraviolet photoionization of astrophysically relevant CnN clusters, n = 4 - 12, in the photon energy range of 8.0 eV to 12.8 eV are presented. The experimental photoionization efficiency curves, combined with electronic structure calculations, provide improved ionization energies of the CnN species. A search through numerous nitrogen-terminated CnN isomers for n=4-9 indicates that the linear isomer has the lowest energy, and therefore should be the most abundant isomer in the molecular beam. Comparison with calculated results also shed light on the energetics of the linear CnN clusters, particularly in the trends of the even-carbon and the odd-carbon series. These results can help guide the search of potential astronomical observations of these neutral molecules together with their cations in highly ionized regions or regions with a high UV/VUV photon flux (ranging from the visible to VUV with flux maxima in the Lyman-a region) in the interstellar medium.
Oh, Won Sup; Chon, Sung-Bin
2016-05-01
Fluid resuscitation, hemostasis, and transfusion is essential in care of hemorrhagic shock. Although estimation of the residual blood volume is crucial, the standard measuring methods are impractical or unsafe. Vital signs, central venous or pulmonary artery pressures are inaccurate. We hypothesized that the residual blood volume for acute, non-ongoing hemorrhage was calculable using serial hematocrit measurements and the volume of isotonic solution infused. Blood volume is the sum of volumes of red blood cells and plasma. For acute, non-ongoing hemorrhage, red blood cell volume would not change. A certain portion of the isotonic fluid would increase plasma volume. Mathematically, we suggest that the residual blood volume after acute, non-ongoing hemorrhage might be calculated as 0·25N/[(Hct1/Hct2)-1], where Hct1 and Hct2 are the initial and subsequent hematocrits, respectively, and N is the volume of isotonic solution infused. In vivo validation and modification is needed before clinical application of this model.
Cao, Jun
2015-06-01
In the present work, the combined electronic structure calculations and dynamics simulations have been performed to explore photocleavages of 2-formyl-2H-azirine and isoxazole in the gas phase and the subsequent rearrangement reactions. The carbonyl n → π* transition induces a cleavage of the C—N single bond of 2-formyl-2H-azirine to yield β-formylvinylnitrene in open-shell singlet state. However, the n → π* excitation of the imine chromophore results in a cleavage of the C—C single bond, producing a nitrile ylide intermediate through an internal conversion to the ground state. β-formylvinylnitrene and nitrile ylide with the carbonyl group are easily transformed into 2-formyl-2H-azirine and oxazole, respectively. The N—O bond cleavages on both S1(1ππ*) and S2(1nNπ*) of isoxazole are ultrafast processes, and they give products of 2-formyl-2H-azirine, 3-formylketenimine, HCN + CHCHO, and HCO + CHCHN. Both 2H-azirines and ketenimines were suggested to be formed from the triplet vinylnitrenes by intersystem crossing in the previous studies. However, our calculations show that the singlet β-formylvinylnitrene is responsible for the formation of 2-formyl-2H-azirine and 3-formylketenimine, and the singlet vinylnitrenes can play a key role in the photoinduced reactions of both 2H-azirines and isoxazoles.
Atif Sattar, M.; Rashid, Muhammad; Hashmi, M. Raza; Ahmad, S. A.; Imran, Muhammad; Hussain, Fayyaz
2016-10-01
Structural, electronic, and magnetic properties of new predicted half-Heusler YCrSb and YMnSb compounds within the ordered MgAgAs C1b-type structure are investigated by employing first-principal calculations based on density functional theory. Through the calculated total energies of three possible atomic placements, we find the most stable structures regarding YCrSb and YMnSb materials, where Y, Cr(Mn), and Sb atoms occupy the (0.5, 0.5, 0.5), (0.25, 0.25, 0.25), and (0, 0, 0) positions, respectively. Furthermore, structural properties are explored for the non-magnetic and ferromagnetic and anti-ferromagnetic states and it is found that both materials prefer ferromagnetic states. The electronic band structure shows that YCrSb has a direct band gap of 0.78 eV while YMnSb has an indirect band gap of 0.40 eV in the majority spin channel. Our findings show that YCrSb and YMnSb materials exhibit half-metallic characteristics at their optimized lattice constants of 6.67 Å and 6.56 Å, respectively. The half-metallicities associated with YCrSb and YMnSb are found to be robust under large in-plane strains which make them potential contenders for spintronic applications.
Energy Technology Data Exchange (ETDEWEB)
Cao, Jun, E-mail: caojunbnu@mail.bnu.edu.cn [Guizhou Provincial Key Laboratory of Computational Nano-Material Sciences, Guizhou Normal College, Guiyang, Guizhou 550018, China and Key Laboratory of Theoretical and Computational Photochemistry, Ministry of Education, College of Chemistry, Beijing Normal University, Beijing 100875 (China)
2015-06-28
In the present work, the combined electronic structure calculations and dynamics simulations have been performed to explore photocleavages of 2-formyl-2H-azirine and isoxazole in the gas phase and the subsequent rearrangement reactions. The carbonyl n → π{sup *} transition induces a cleavage of the C—N single bond of 2-formyl-2H-azirine to yield β-formylvinylnitrene in open-shell singlet state. However, the n → π{sup *} excitation of the imine chromophore results in a cleavage of the C—C single bond, producing a nitrile ylide intermediate through an internal conversion to the ground state. β-formylvinylnitrene and nitrile ylide with the carbonyl group are easily transformed into 2-formyl-2H-azirine and oxazole, respectively. The N—O bond cleavages on both S{sub 1}({sup 1}ππ{sup *}) and S{sub 2}({sup 1}n{sub N}π{sup *}) of isoxazole are ultrafast processes, and they give products of 2-formyl-2H-azirine, 3-formylketenimine, HCN + CHCHO, and HCO + CHCHN. Both 2H-azirines and ketenimines were suggested to be formed from the triplet vinylnitrenes by intersystem crossing in the previous studies. However, our calculations show that the singlet β-formylvinylnitrene is responsible for the formation of 2-formyl-2H-azirine and 3-formylketenimine, and the singlet vinylnitrenes can play a key role in the photoinduced reactions of both 2H-azirines and isoxazoles.
Institute of Scientific and Technical Information of China (English)
许仕荣; 赵伟; 王长平; 徐洪福
2012-01-01
Among many water chemical stability indexes, the calcium carbonate precipitation potential (CCPP) is the one that can quantitatively analyze the accurate dissolved or precipitated CaCO3. This paper deduced a calculation model of CCPP from theory, and offered a calculating solving by Matlab. Compared with other existing related softwares, the results of CCPP were closer to the experimental results than the results of other softwares, therefor it could be used to replace the experimental data for water quality chemical stability analysis.%水质化学稳定性评价指数较多,其中碳酸钙沉淀势(CCPP)是一个能定量分析CaCO3溶解或沉淀的精确指数.从理论上推导了CCPP计算模型,并基于Matlab计算求解.模型计算结果与已有相关软件的计算结果相比,该理论模型的计算值更接近试验结果,可以用其代替试验值进行水质化学稳定性分析.
Helmrot, E; Alm Carlsson, G
1996-01-01
In the radiological process it is necessary to develop tools so as to explore how X-rays can be used in the most effective way. Evaluation of models to derive measures of image quality and risk-related parameters is one possibility of getting such a tool. Modelling the image receptor, an important part of the imaging chain, is then required. The aim of this work was to find convenient and accurate ways of describing the blackening of direct dental films by X-rays. Since the beginning of the 20th century, the relation between optical density and photon interactions in the silver bromide in X-ray films has been investigated by many authors. The first attempts used simple quantum theories with no consideration of underlying physical interaction processes. The theories were gradually made more realistic by the introduction of dosimetric concepts and cavity theory. A review of cavity theories for calculating the mean absorbed dose in the AgBr grains of the film emulsion is given in this work. The cavity theories of GREENING (15) and SPIERS-CHARLTON (37) were selected for calculating the mean absorbed dose in the AgBr grains relative to the air collision kerma (Kc,air) of the incident photons of Ultra-speed and Ektaspeed (intraoral) films using up-to-date values of interaction coefficients. GREENING'S theory is a multi-grain theory and the results depend on the relative amounts of silver bromide and gelatine in the emulsion layer. In the single grain theory of SPIERS-CHARLTON, the shape and size of the silver bromide grain are important. Calculations of absorbed dose in the silver bromide were compared with measurements of optical densities in Ultra-speed and Ektaspeed films for a broad range (25-145 kV) of X-ray energy. The calculated absorbed dose values were appropriately averaged over the complete photon energy spectrum, which was determined experimentally using a Compton spectrometer. For the whole range of tube potentials used, the measured optical densities of the
Energy Technology Data Exchange (ETDEWEB)
Zhang, Zhongyu; Bi, Caifeng; Fan, Yuhua; Zhang, Xia; Zhang, Nan; Yan, Xingchen; Zuo, Jian [Ocean Univ. of China, Qingdao (China)
2014-06-15
A novel complex [Zn(phen)(o-AB){sub 2}] [phen: 1,10-phenanthroline o-AB: o-aminobenzoic acid] was synthesized and characterized by elemental analysis and X-ray diffraction single-crystal analysis. The crystal crystallizes in monoclinic, space group P2(1)/c with a = 7.6397(6) A, b = 16.8761(18) A, c = 17.7713(19) A, α = 90 .deg., β = 98.9570(10) .deg., γ = 90 .deg., V = 2.2633(4) nm{sup 3}, Z = 4, F(000) = 1064, S = 1.058, Dc = 1.520 g·cm{sup -3}, R{sub 1} = 0.0412, wR{sub 2} = 0.0948, μ = 1.128 mm{sup -1}. The Zn(II) is six coordinated by two nitrogen and four oxygen atoms from the 1,10-phenanthroline and o-aminobenzoic acid to furnish a distorted octahedron geometry. The complex exhibits intense fluorescence at room temperature. Theoretical studies of the title complex were carried out by density functional theory (DFT) B3LYP method. CCDC: 898291.
Energy Technology Data Exchange (ETDEWEB)
Li, L. H.; Hu, L.; Yang, S. J.; Wang, W. L.; Wei, B., E-mail: bbwei@nwpu.edu.cn [Department of Applied Physics, Northwestern Polytechnical University, Xi' an 710072 (China)
2016-01-21
The thermodynamic properties, including the density, volume expansion coefficient, ratio of specific heat to emissivity of intermetallic Ni{sub 7}Zr{sub 2} alloy, have been measured using the non-contact electrostatic levitation technique. These properties vary linearly with temperature at solid and liquid states, even down to the obtained maximum undercooling of 317 K. The enthalpy, glass transition, diffusion coefficient, shear viscosity, and surface tension were obtained by using molecular dynamics simulations. Ni{sub 7}Zr{sub 2} has a relatively poor glass forming ability, and the glass transition temperature is determined as 1026 K. The inter-diffusivity of Ni{sub 7}Zr{sub 2} alloy fitted by Vogel–Fulcher–Tammann law yields a fragility parameter of 8.49, which indicates the fragile nature of this alloy. Due to the competition of increased thermodynamic driving force and decreased atomic diffusion, the dendrite growth velocity of Ni{sub 7}Zr{sub 2} compound exhibits double-exponential relationship to the undercooling. The maximum growth velocity is predicted to be 0.45 m s{sup −1} at the undercooling of 335 K. Theoretical analysis reveals that the dendrite growth is a diffusion-controlled process and the atomic diffusion speed is only 2.0 m s{sup −1}.
Energy Technology Data Exchange (ETDEWEB)
Pate, Brooks H.; Seifert, Nathan A. [Department of Chemistry, University of Virginia, Charlottesville, VA 22904 (United States); Guirgis, Gamil A. [Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424 (United States); Deodhar, Bhushan S.; Klaassen, Joshua J.; Darkhalil, Ikhlas D. [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Crow, Joseph A. [Department of Physics, University of Missouri-Kansas City, Kansas City, MO 64110 (United States); Wyatt, Justin K.; Dukes, Horace W. [Department of Chemistry and Biochemistry, College of Charleston, Charleston, SC 29424 (United States); Durig, James R., E-mail: durigj@umkc.edu [Department of Chemistry, University of Missouri-Kansas City, Kansas City, MO 64110 (United States)
2013-04-18
Highlights: • Structural parameters have been determined for the stable twist conformer. • Rotational constants for the six isotopologues for the twist conformer were determined from the microwave spectra. • Vibrational assignments are given for the molecule. • Ab intio and density functional theory calculations have been carried out for all possible conformers. - Abstract: The FT-microwave spectrum of 1,1,3,3-tetrafluoro-1,3-disilacyclopentane (c-C{sub 3}H{sub 6}Si{sub 2}F{sub 4}) has been recorded and 339 transitions for 6 isotopologues have been assigned for the twist conformation. The ground state rotational constants were determined with values for the normal species: A = 2102.74026(68), B = 751.34319(32), C = 736.51478(31). Adjusted r{sub 0} parameters are reported with distances (Å): rC{sub α}–Si = 1.859(2), rSi–C{sub β} = 1.864(2), rSi–F{sub 1} = 1.583(3), rSi–F{sub 2} = 1.578(3), and rC{sub β}–C{sub β} = 1.559(3), and angles (°): ∠SiC{sub α}Si = 102.8(3), ∠C{sub α}SiC{sub β} = 104.3(3), ∠SiC{sub β}C{sub β′} = 106.6(3), τC{sub β}SiC{sub α}Si = 10.7(3), and τ SiC{sub β}C{sub β′}Si = 40.8(3). The conformational stabilities have been predicted from ab initio calculations utilizing several various basis sets. Vibrational assignments have been provided for the observed bands for the twist conformer which are supported by ab initio calculations to predict harmonic force constants, vibrational wavenumbers, infrared intensities, Raman activities and depolarization ratios. The results are discussed and compared to the corresponding properties of some related molecules.
Iriarte, Ana G; Cutin, Edgardo H; Argüello, Gustavo A
2014-01-01
The synthesis of [chloro(difluor)acetyl]phosphorimidic trichloride (ClF2CC(O)NPCl3), together with a tentative assignment of the vibrational, NMR and mass spectra, are reported. Quantum chemical calculations (MP2 and B3LYP methods with 6-311+G(d) and 6-311+G(2df,p) basis sets) predict three stable conformers in the gas phase (syn, gauche and anti, defined according to the rotation around both the ClCCN and the CCNP dihedral angles). However, only a single C1 symmetry conformer is observed in the liquid phase, possessing the CO double bond in synperiplanar orientation with respect to the PN double bond, and the ClC bond distorted from the plane defined by the CC(O)NP entity. A Natural Bond Orbital (NBO) analysis was carried out for the title compound and related molecules in order to provide an explanation about the electronic properties.
Institute of Scientific and Technical Information of China (English)
Jingjie GUO; Guizhong LIU; Yanqing SU; Jun JIA; Hengzhi FU
2004-01-01
A new model was established to calculate the real vapor pressure of Al in the molten Ni-xAI (at. Pct) (x=25～50)alloy. The effects of the holding time, chamber pressure, mole fraction of Al and melting temperature on the real vapor pressure of Al in the vacuum chamber were analyzed. Because of the impeding effect of the real vapor pressure on the evaporation loss rate, within a short time (less than 10 s), the real vapor pressure tends to a constant value.When the chamber pressure is less than the saturated vapor pressure of Al, the real vapor pressure of Al is equal to the chamber pressure. While when the chamber pressure is higher than the saturated vapor pressure, the real vapor pressure of Al approaches to the saturated vapor pressure of Al of the same condition.
Energy Technology Data Exchange (ETDEWEB)
Dolly, S [Washington University School of Medicine, Saint Louis, MO (United States); University of Missouri, Columbia, MO (United States); Chen, H; Anastasio, M; Mutic, S; Li, H [Washington University School of Medicine, Saint Louis, MO (United States)
2015-06-15
Purpose: Local noise power spectrum (NPS) properties are significantly affected by calculation variables and CT acquisition and reconstruction parameters, but a thoughtful analysis of these effects is absent. In this study, we performed a complete analysis of the effects of calculation and imaging parameters on the NPS. Methods: The uniformity module of a Catphan phantom was scanned with a Philips Brilliance 64-slice CT simulator using various scanning protocols. Images were reconstructed using both FBP and iDose4 reconstruction algorithms. From these images, local NPS were calculated for regions of interest (ROI) of varying locations and sizes, using four image background removal methods. Additionally, using a predetermined ground truth, NPS calculation accuracy for various calculation parameters was compared for computer simulated ROIs. A complete analysis of the effects of calculation, acquisition, and reconstruction parameters on the NPS was conducted. Results: The local NPS varied with ROI size and image background removal method, particularly at low spatial frequencies. The image subtraction method was the most accurate according to the computer simulation study, and was also the most effective at removing low frequency background components in the acquired data. However, first-order polynomial fitting using residual sum of squares and principle component analysis provided comparable accuracy under certain situations. Similar general trends were observed when comparing the NPS for FBP to that of iDose4 while varying other calculation and scanning parameters. However, while iDose4 reduces the noise magnitude compared to FBP, this reduction is spatial-frequency dependent, further affecting NPS variations at low spatial frequencies. Conclusion: The local NPS varies significantly depending on calculation parameters, image acquisition parameters, and reconstruction techniques. Appropriate local NPS calculation should be performed to capture spatial variations of
Theoretical model and numerical calculation of pellet ablation rate%弹丸消融速率的理论模型及数值计算
Institute of Scientific and Technical Information of China (English)
程发银
2016-01-01
建立了计算托卡马克加料中弹丸消融的物理模型，结合1维输运模型编制了1.5维弹丸消融计算机模拟代码。使用ITER-FEAT的相关参数，对半径为6mm，初速度为2000m·s−1，从低磁场侧注入弹丸的消融速率进行了模拟计算。结果显示，弹丸消融速率先随注入深度而逐渐增大，最大消融速率约6×1026s−1，然后由于弹丸半径的减小，消融速率迅速减小，穿透深度约0.45m。这一结果与中性气体屏蔽模型(NGS)的结果一致，证明计算代码正确有效。同时，从计算结果反映出，对ITER这样的堆级托卡马克，采用常规弹丸注入方式，尽管速度高达2000m·s−1，穿透深度也远未达到等离子体中心，因此应采取其他有效措施来提高等离子体加料效率。%A physical model of calculating the pellet ablation rate in tokamak fueling was proposed, which was combined with the 1-D transport model to develop the 1.5D pellet ablation code. Using the parameter of ITER-FEAT, the pellet ablation rate of radius 6mm with initial injection speed of 2000m·s−1 when injecting from low field side was calculated. The results show that the ablation rate first increases gradually over time, then decreases rapidly because of decrement of pellet radius, the maximum ablation rate is about 6×1026s−1, the total penetration depth is about 0.45m. This result is consistent with that gained from the neutral gas shielding model (NGS), and it proved the validity of the code. At the same time, the calculation result indicate that, for the reactor grade tokamak such as ITER, using conventional pellet injection method, the penetration depth is small enough so that the core plasma fueling cannot be achieved although the injection speed is 2000m·s−1. Therefore in order to raise the plasma fueling efficiency, other effective pellet injection scenario must be chosen.
Monari, Antonio; Rivail, Jean-Louis; Assfeld, Xavier
2013-02-19
Molecular mechanics methods can efficiently compute the macroscopic properties of a large molecular system but cannot represent the electronic changes that occur during a chemical reaction or an electronic transition. Quantum mechanical methods can accurately simulate these processes, but they require considerably greater computational resources. Because electronic changes typically occur in a limited part of the system, such as the solute in a molecular solution or the substrate within the active site of enzymatic reactions, researchers can limit the quantum computation to this part of the system. Researchers take into account the influence of the surroundings by embedding this quantum computation into a calculation of the whole system described at the molecular mechanical level, a strategy known as the mixed quantum mechanics/molecular mechanics (QM/MM) approach. The accuracy of this embedding varies according to the types of interactions included, whether they are purely mechanical or classically electrostatic. This embedding can also introduce the induced polarization of the surroundings. The difficulty in QM/MM calculations comes from the splitting of the system into two parts, which requires severing the chemical bonds that link the quantum mechanical subsystem to the classical subsystem. Typically, researchers replace the quantoclassical atoms, those at the boundary between the subsystems, with a monovalent link atom. For example, researchers might add a hydrogen atom when a C-C bond is cut. This Account describes another approach, the Local Self Consistent Field (LSCF), which was developed in our laboratory. LSCF links the quantum mechanical portion of the molecule to the classical portion using a strictly localized bond orbital extracted from a small model molecule for each bond. In this scenario, the quantoclassical atom has an apparent nuclear charge of +1. To achieve correct bond lengths and force constants, we must take into account the inner shell of
Theoretical calculation of the 1CCl2+O2 reaction mechanism%1CCl2+O2反应机理的理论研究
Institute of Scientific and Technical Information of China (English)
石从云; 伊双莉
2011-01-01
在B3LYP/6-311+ +G(d,p)水平上研究了二氯卡宾1CCl2与O2在单重态势能面上的微观反应机理.优化了中间体、过渡态和产物的构型,并得到了相应的能量值.研究发现1CCl2+O2反应有4种产物通道:CO2+Cl2、CO2+2Cl、ClCO+ClO和CO+Cl2O,且前两种是主要通道.%The dissolution enthalpies of the[Tb(Gly)3·6H2O(s)+3 Gly (s)] and Tb(Gly)3Cl3· 3H2O(s) in 2 mol·L-1 HC1 solution have been measured at 298.2 K by isoperibol calorimeter.The standard molar reaction enthalpy of the coordination reaction of terbium chloride with glycine has been determined by a thermochemical cycle, △rHmθ(298.15 K) = -6.247±0.060 kJ·mol-1.According to the results, the standard molar enthalpy of formation of Tb(Gly)3Cl3·3H2O(s) has been calculated to be △rHmθ(298.15 K) =-3631.9±2.9 kJ·mol-1, and the molar dissolution enthalpy of Tb(Gly)3Cl3 ·3H2O(s) in water has been measured by isopribel calorimeter, the standard molar enthalpy of formation of Tb(Gly)33+(aq) has been calculated at 298.15 K to be △rHmθ[Tb(Gly)33+ ,aq,298.15 K] = -2 260.6+2.9 kJ·mol-1.
Theoretical Calculation for the Thermochemistry of Modified ANFO Explosive%改性铵油炸药的热化学计算与分析
Institute of Scientific and Technical Information of China (English)
刘丽梅; 肖国; 夏建才; 张永明
2014-01-01
Based on B-W rule the explosion reaction equation of modified ANFO explosive were established. The constant volume explosion heat of modified ANFO explosive were calculated based on Hess law, and Specific Heat Capacity (SHC) of explosion products were calculated with the method of weighted averages. The result shows that constant volume explosion heat of opencast modified ANFO explosive, rock modified ANFO explosive and water resistant rock modified ANFO explosive is-3777.00 kJ· kg-1, the explosion temperature is 2771 K, Specific Volume is 965.15 L· kg-1, that constant volume explosion heat of the class I and II coal mine permissible modified ANFO explosive are-2567.69kJ· kg-1 and-2312.09 kJ· kg-1 respectively, the explosion temperature are 2257 K and 2127K respectively, Specific Volume are 842.26 L· kg-1 and 817.06L· kg-1 respectively.%运用 B-W 法确定改性铵油炸药的爆炸反应方程式，用盖斯定律计算定容爆热，用加权法计算爆炸产物的摩尔定容热容，研究计算了露天型改性铵油炸药、岩石型改性铵油炸药、抗水岩石型改性铵油炸药爆热为-3777.00 kJ· kg-1、爆温为2771 K，比容为965.15 L· kg-1，一级煤矿许用改性铵油炸药、二级煤矿许用改性铵油炸药的爆热分别为-2567.69kJ· kg-1、-2312.09 kJ· kg-1，爆温依次为2257 K、2127K，比容为842.26 L· kg-1、817.06L· kg-1。
Lucas, J. N.; Deng, W.; Oram, S. W.; Hill, F. S.; Durante, M.; George, K.; Wu, H.; Owens, C. L.; Yang, T.
1999-01-01
In the present study, F ratios for both stable chromosome aberrations, i.e. ratios of translocations to pericentric inversions, and unstable aberrations, i.e. dicentrics and centric rings, were measured using fluorescence in situ hybridization. F ratios for stable aberrations measured after exposure to low (2.89 Gy 60Co gamma rays) and high-LET (0.25 Gy 56Fe ions; 1.25 Gy 56Fe ions; 3.0 Gy 12C ions) radiation were 6.5 +/- 1.5, 4.7 +/- 1.6, 9.3 +/- 2.5 and 10.4 +/- 3.0, respectively. F ratios for unstable aberrations measured after low (2.89 Gy 60Co gamma rays) and high-LET (0.25 Gy 56Fe ions; 3.0 Gy 12C ions) radiations were 6.5 +/- 1.6, 6.3 +/- 2.3 and 11.1 +/- 3.7, respectively. No significant difference between the F ratios for low- and high-LET radiation was found. Further tests on the models for calculation of the F ratio proposed by Brenner and Sachs (Radiat. Res. 140, 134-142, 1994) showed that the F ratio may not be straightforward as a practical fingerprint for densely ionizing radiation.
Dolmella, A.; Bandoli, G.; Cavallin, M.
2000-08-01
LU 25-109 ( II) and WAL 2014 (talsaclidine, III) are two M1 muscarinic agonists chemically related to the natural substance arecoline ( I). All these compounds have beneficial effects on memory and cognition in animals and humans, and they have been proposed in the treatment of Alzheimer's disease, but only III will likely find a place in therapy. In this work we have investigated the solid state structures of II and III, and the X-ray structures of the two molecules and of the parent compound I have been used to input a series of computational chemistry efforts. In particular, the X-ray geometries have been manipulated to model 20 molecular structures ( 1- 20) which have been submitted to ab initio, semiempirical quantum mechanics and molecular mechanics calculations. The conformational space accessible to the 20 structures has been assessed by means of potential energy maps. The reactivities of 1- 20 have been estimated by examining at the graphics terminal the composition and the extension of the frontier orbitals (HOMOs and LUMOs) and of the molecular electrostatic potential. The information obtained has been interpreted to explain the different degrees of activity shown by I- III. Our data indicate that III has better in vivo activity for its intermediate size, less polar surface, conformational rigidity and orientation of reactive domains.
Lestinsky, M; Bernhardt, D; Grieser, M; Hoffmann, J; Lukić, D; Müller, A; Orlov, D A; Repnow, R; Savin, D W; Schmidt, E W; Schnell, M; Schippers, S; Wolf, A; Yu, D
2009-01-01
We have measured electron-ion recombination for Fe$^{9+}$ forming Fe$^{8+}$ and for Fe$^{10+}$ forming Fe$^{9+}$ using merged beams at the TSR heavy-ion storage-ring in Heidelberg. The measured merged beams recombination rate coefficients (MBRRC) for relative energies from 0 to 75 eV are presented, covering all dielectronic recombination (DR) resonances associated with 3s->3p and 3p->3d core transitions in the spectroscopic species Fe X and Fe XI, respectively. We compare our experimental results to multi-configuration Breit-Pauli (MCBP) calculations and find significant differences. From the measured MBRRC we have extracted the DR contributions and transform them into plasma recombination rate coefficients (PRRC) for astrophysical plasmas with temperatures from 10^2 to 10^7 K. This spans across the regimes where each ion forms in photoionized or in collisionally ionized plasmas. For both temperature regimes the experimental uncertainties are 25% at a 90% confidence level. The formerly recommended DR data sev...
Directory of Open Access Journals (Sweden)
Sanju Gupta
2016-07-01
thin heterogeneous composite electrodes. We attribute the superior performance to the open graphene topological network being beneficial to available ion diffusion sites and the faster transport kinetics having a larger accessible geometric surface area and synergistic integration with optimal nanostructured VO loading. Computational simulations via periodic density functional theory (DFT with and without V2O5 adatoms on graphene sheets are also performed. These calculations determine the total and partial electronic density of state (DOS in the vicinity of the Fermi level (i.e., higher electroactive sites, in turn complementing the experimental results toward surface/interfacial charge transfer on heterogeneous electrodes.
Directory of Open Access Journals (Sweden)
Martín A Dragonetti
2008-01-01
Full Text Available Una serie de compuestos derivados de quinoxalina, benzoxazina y benzodiazepina fue utilizada para realizar un estudio teórico preliminar que permita plantear un potencial grupo farmacóforo que conduzca a la síntesis de posibles inhibidores no-nucleosídicos de la transcriptasa reversa del virus del SIDA. El estudio teórico se llevó a cabo utilizando modelado molecular asistido por computadora. Se analizaron las conformaciones obtenidas para los compuestos en estudio (densidad atómica de carga y del arreglo espacial de los grupos atómicos. Los resultados se compararon con la información aportada por los complejos cristalográficos (fármaco-transcriptasa reversa extraídos de una base de datos de proteínas. Este estudio permitió establecer los requerimientos esenciales para que un compuesto se comporte como inhibidor de la transcriptasa reversa del VIH-1 y encontrar el potencial farmacóforo común a este tipo de fármacos.A series of quinoxaline, benzooxazine and benzodiazepine derivatives was selected to perform a preliminary theoretical study tending to find a potential pharmacophoric group that could lead to the synthesis of non nucleoside inhibitors of the HIV-1 reverse transcriptase. The theoretical study was performed using computer-assisted molecular modeling. The achieved final conformations of the selected compounds were compared and analyzed in terms of the atomic charge density and the atomic groups arrangements. The results were compared with information extracted from the crystallographic complexes (drug-reverse transcriptase reported in a protein data bank. This analysis enables to establish the essential requirements for a compound inhibition behavior of the HIV-1 reverse transcriptase and to find a potential pharmacophore common to this type of compounds.
Institute of Scientific and Technical Information of China (English)
陈军; 龙瑶; 陈栋泉
2013-01-01
高能炸药热导率参数的计算是一个难点问题.介绍了我们发展的两种计算复杂结构炸药单晶热导率的方法:第一种方法基于运动方程,推导出了固体内较直观简洁的热流公式,可以研究不同方向HMX炸药的热导率;第二种方法基于声子-声子散射模型,结合德拜模型,计算高压下HMX炸药的热导率.两种方法各有其优缺点.利用这两种方法,计算了HMX炸药在高压下的热导率,并得到了高压下HMX热导率随压强的变化关系.%The theoretical calculation on thermal conductivity of explosive is still one problem.We presented our developed two calculation methods for thermal conductivity of explosive.The first one is based on atomic motion equation.We derived the formulations of thermal flux in system and thermal conductivity of system.It is suitable to calculate the thermal conductivity in different directions.The second one is based on the phonon-phonon dispersion model and Debye model.This method can effectively calculate the thermal conductivity under pressure.Using these two methods,we have calculated the thermal conductivity of HMX under pressure,and deeply analyzed the factors which affect the thermal conductivity of HMX.
Institute of Scientific and Technical Information of China (English)
高乃云; 黄鑫; 蔡云龙; 梅红; 丁国际
2011-01-01
使用phreeqc软件计算黄浦江水的碳酸钙沉淀势(Calcium Carbonate Precipitation Potential,CCPP),首次分析了地表水CCPP的理论计算值与实验值的差异原因,并作黄浦江水pH与CCPP的统计关联分析.结果表明:免费开源的 phreeqc程序计算CCPP的精度同商业软件不相上下.CCPP计算值与实验值存在较大差距,主要原因在于计算时水质参数偏少.统计分析表明,黄浦江水的pH与CCPP值有一定关联,控制计算CCPP值为6～10mg/L时,实际水体CCPP值约为0～4 mg/L,基本满足水质稳定要求.%Phreeqc was used to calculate the calcium carbonate precipitation potential(CCPP) of Huang-pu river water. The possible reasons for the differential between calculated and experimental CCPP were firstly analyzed. Furthermore a statistical analysis was made to study the correlation between pH and CCPP of the raw waters. The results show phreeqc, a free open-source program, has similar high level of calculation accuracy with other commercial software. The difference of CCPP values between experimental and theoretical calculation are considerable, which is mainly due to the lack of water indexes. With a statistical analysis, the correlation between pH and CCPP of Huangpu river water was found. The chemical stability of raw water could be achieved by adjusting the calculated CCPP to be 0～4 mg/L CaCO3 and the experimental CCPP to be 0~4 mg/L CaCO3.
Dorofeeva, Olga V; Vogt, Natalja; Vogt, Jürgen; Popik, Mikhail V; Rykov, Anatolii N; Vilkov, Lev V
2007-07-19
The molecular structure of 1,3-dihydroxyacetone (DHA) has been studied by gas-phase electron diffraction (GED), combined analysis of GED and microwave (MW) data, ab initio, and density functional theory calculations. The equilibrium re structure of DHA was determined by a joint analysis of the GED data and rotational constants taken from the literature. The anharmonic vibrational corrections to the internuclear distances (re-ra) and to the rotational constants (B(i)e-B(i)0) needed for the estimation of the re structure were calculated from the B3LYP/cc-pVTZ cubic force field. It was found that the experimental data are well reproduced by assuming that DHA consists of a mixture of three conformers. The most stable conformer of C2v symmetry has two hydrogen bonds, whereas the next two lowest energy conformers (Cs and C1 symmetry) have one hydrogen bond and their abundance is about 30% in total. A combined analysis of GED and MW data led to the following equilibrium structural parameters (re) of the most abundant conformer of DHA (the uncertainties in parentheses are 3 times the standard deviations): r(C=O)=1.215(2) A, r(C-C)=1.516(2) A, r(C-O)=1.393(2) A, r(C-H)=1.096(4) A, r(O-H)=0.967(4) A, angleC-C=O=119.9(2) degrees, angleC-C-O=111.0(2) degrees, angleC-C-H=108.2(7) degrees, angleC-O-H=106.5(7) degrees. These structural parameters reproduce the experimental B(i)0 values within 0.05 MHz. The experimental structural parameters are in good agreement with those obtained from theoretical calculations. Ideal gas thermodynamic functions (S degrees (T), C degrees p(T), and H degrees (T)-H degrees (0)) of DHA were calculated on the basis of experimental and theoretical molecular parameters obtained in this work. The enthalpy of formation of DHA, -523+/-4 kJ/mol, was calculated by the atomization procedure using the G3X method.
Energy Technology Data Exchange (ETDEWEB)
Ognibene, T J; Bench, G; Brown, T A; Vogel, J S
2005-12-13
Ion-optics calculations were performed for a new ion source and injection beam line. This source, which can accept both solid and gaseous targets, will be installed onto the 1-MV BioAMS spectrometer at the Center for Accelerator Mass Spectrometry, located at Lawrence Livermore National Laboratory and will augment the current LLNL cesium-sputter solid sample ion source. The ion source and its associated injection beam line were designed to allow direct quantification of {sup 14}C/{sup 12}C and {sup 3}H/{sup 1}H isotope ratios from both solid and gaseous targets without the need for isotope switching. Once installed, this source will enable the direct linking of a nanoflow LC system to the spectrometer to provide for high-throughput LC-AMS quantitation from a continuous flow. Calculations show that, for small samples, the sensitivity of the gas-accepting ion source could be precision limited but zeptomole quantitation should be feasible.
Yonezawa, Shuji; Fujiwara, Kenichiro; Yamamoto, Takahiko; Hattori, Kazunari; Yamakawa, Hidekuni; Muto, Chie; Hosono, Motoko; Tanaka, Yoshikazu; Nakano, Toru; Takemoto, Hiroshi; Arisawa, Mitsuhiro; Shuto, Satoshi
2013-11-01
For further investigation of BACE1 inhibitors using conformational restriction with sp(3) hybridized carbon, we applied this approach to 6-substituted aminopyrimidone derivatives 3 to improve the inhibitory activity by reducing the entropic energy loss upon binding to BACE1. Among eight stereoisomers synthesized, [trans-(1'R,2'R),6S] isomer 6 exhibited the best BACE1 inhibitory activity, which was statistically superior to that of the corresponding ethylene linker compound (R)-3. Combinational examinations of the binding mode of 6 were performed, which included isothermal titration calorimetry (ITC), X-ray crystallographic structure analysis and theoretical calculations, to clarify the effect of our conformational restriction approach. From the ITC measurement, the binding entropy of 6 was found to be ∼0.5kcal larger than that of (R)-3, which is considered to be affected by conformational restriction with a cyclopropane ring.
Energy Technology Data Exchange (ETDEWEB)
Toreti, Dalila; Xavier, Clarice; Moura, Fabio, E-mail: clarice.xavier@rem.ind.b, E-mail: fabio.moura@rem.ind.b [REM Industria e Comercio Ltda., Sao Paulo, SP (Brazil)
2011-10-26
The CyberKnife robotic system uses a manipulator with six grade of freedom for positioning a 6 MV Linac accelerator for treatment of lesions. This paper presents calculations for a standard room, with 200 cm of thickness walls primary, build for a CyberKnife system, and calculations for a room originally designed for a Linac conventional (with gantry), with secondary barriers of 107 cm thickness. After the realization of shielding for both rooms, the results shown that walls of standard room with 200 cm thickness are adequate for the secondary shield, and for a room with a conventional Linac, from all six evaluated points, two would require additional shielding of nine cm and four cm of concrete with 2.4 g/cubic cm. This shows that the CyberKnife system can be installed in a originally designed room for a conventional Linac with neither restrict nor any shielding, since no incidence of beams on the secondary barriers is existent
Towards general information theoretical representations of database problems
Energy Technology Data Exchange (ETDEWEB)
Joslyn, C.
1997-06-01
General database systems are described from the General Systems Theoretical (GST) framework. In this context traditional information theoretical (statistical) and general information theoretical (fuzzy measure and set theoretical, possibilistic, and random set theoretical) representations are derived. A preliminary formal framework is introduced.
DEFF Research Database (Denmark)
Bruus, Henrik
in complexity, a proper theoretical understanding becomes increasingly important. The basic idea of the book is to provide a self-contained formulation of the theoretical framework of microfluidics, and at the same time give physical motivation and examples from lab-on-a-chip technology. After three chapters...
Armentano, Donatella; De Munno, Giovanni; Di Donna, Leonardo; Sindona, Giovanni; Giorgi, Gianluca; Salvini, Laura; Napoli, Anna
2004-02-01
Electrospray tandem mass spectrometry (ESI-MS/MS) is used to evaluate the assembling of cytosine and thymine nucleosides in the gas phase, through the formation of hydrogen bonded supermolecules. Mixtures of cytidine analogues and homologues deliver in the gas phase proton-bound heterodimers stabilized by multiple interactions, as proven by the kinetics of their dissociation into the corresponding protonated monomers. Theoretical calculations, performed on initial structures of methylcytosine homodimers available in the literature, converged to a minimized structure whereby the two pyrimidine rings interact through the formation of three hydrogen bonds of similar energy. The crystallographic data here reported show the equivalency of the two interacting pyrimidines which is attributable to the presence of an inversion center. Thymine and uracil pyrimidyl nucleosides form, by ESI, gaseous proton-bound dimers. The kinetic of their dissociation into the related protonated monomers shows that the nucleobases are weekly interacting through a single hydrogen bond. The minimized structure of the protonated heterodimer formed by thymine and N-1-methylthymine confirmed the existence of mainly one hydrogen bond which links the two nucleobases through the O4 oxygens. No crystallographic data exists on thymine proton-bound species, nor have we been able to obtain these aggregates in the solid phase. The gaseous phase, under high vacuum conditions, seems therefore a suitable environment where vanishing structures produced by ESI can be studied with a good degree of approximation.
Institute of Scientific and Technical Information of China (English)
刘洪
2012-01-01
主要针对高频线圈于单晶生长过程中，在高频电流及棒体的高温作用下，产生的附加扭矩，改变线圈的设计外形，进行了原因研究、理论计算，并对单晶生长的影响进行了分析。通过采取适当的措施，降低由于线圈的形变对单晶的影响，提高单晶的成晶率。%Change the shape of the coil design for high-frequency coil in the crystal growth process, high-frequency current and the high temperature of the rods, resulting in additional torque, why study the theoretical calculations, and crystal growth the impact analysis. Take appropriate measures to reduce the coil deformation of single crystals, to improve the yield of single crystal.
Energy Technology Data Exchange (ETDEWEB)
Brasil, Davi S.B.; Mueller, Adolfo H.; Guilhon, Gisele M.S.P.; Alves, Claudio N., E-mail: muller@ufpa.b [Universidade Federal do Para (UFPA), Belem, PA (Brazil). Inst. de Ciencias Exatas e Naturais; Peris, Gabriel; Llusar, Rosa; Moliner, Vicent [Universitat Jaume I, Castellon (Spain).VDept. de Quimica Fisica i Analitica
2010-07-01
Phytochemical studies of the bark and leaves of Croton palanostigma Klotzsch (Euphorbiaceae) led to the isolation of a new clerodane diterpene, 8-epicordatin (2), in addition to 12-oxohardwickiic acid methyl ester (3), aparisthman, cordatin (1), ent-trachyloban-18-oic acid, ent-13-epimanoyl oxide, ent-3-oxo-13-epimanoyl oxide, ent-3{beta}-hydroxy-13-epimanoyl oxide, sitosterol, stigmasterol, stigmastan-3-one, 6{beta}-hydroxystigmast-4-en-3-one, 6{beta}-hydroxystigmasta-4,22-dien-3-one, stigmast-4-en-3-one, stigmasta-4,22-dien-3-one, 3-O-acetylaleuritolic acid, 11a-hydroxyurs-12-en-3-one, a-amyrenone, 24-methylenecycloartenone and lupenone. These compounds were isolated using typical phytochemical procedures and the structures were deduced from spectroscopic studies, including 2D NMR experiments. In addition, the crystalline structure of 8-epicordatin (2) was determined by X-ray diffraction. NMR theoretical calculations at the B3PW91/DGDZVP level were used to confirm the assignment of the chemical shifts of the H-7a and H-7{beta} hydrogens of 8-epicordatin. (author)
Preliminary calculation of proliferation resistance of Pyroprocess
Energy Technology Data Exchange (ETDEWEB)
Yeop, Joung Sung; Chang, Soon Heung [Korea Advanced Institute Science and Technology, Daejeon (Korea, Republic of)
2010-10-15
We measured the proliferation resistance of Pyroprocess by using multi-attribute utility analysis method. This methodology is intended to allow for the assessment of the effectiveness of safeguards implementation at facilities within a large-scale fuel cycle and allow for the ability to choose technologies based in part on their effectiveness to deter the proliferation of nuclear materials. Pyroprocess may be the part of new Fuel cycle that includes PWR, fuel storage facilities, Pryoprocessing facilities, SFR, fuel repository facilities. In this paper we only focused on Pyroprocessing facilities as a single process
Institute of Scientific and Technical Information of China (English)
苏海鹏; 毕福强; 葛忠学; 汪伟; 朱勇
2014-01-01
Three dinitro heteroaromatic ring-fused pyridazines,4,7-dinitrofurazano[3,4-d]pyridazine (DNFP),4,7-dinitrofuroxano[3,4-d]pyridazine (DNFOP)and 5,8-dinitropyridazino [4,5-e][1 ,2,3,4 ]tetrazine 1,3-dioxide (DNPTDO)were designed.On the basis of the stable geometries optimized at B3LYP/6-31G** theoretical level, the Wiberg bond order,bond dissociation energy (BDE),electrostatic potential,theoretical density and solid state phase heats of formation of title compounds were calculated at the same theoretical level.The detonation velocities (D),detonation pressures (p )and the performances of these compounds as monopropellants were predicted by Kamlet-Jacobs formula and the minimum free energy method,respectively.The results show that the BDE,ρ,D , and p of DNFOP are 80.37 kJ/mol,1.939 g/cm3 ,9 151 m/s,and 39.54 GPa,respectively,and the BDE,ρ,D ,and p of DNPTDO are 208.59 kJ/mol,1 .942 g/cm3 ,9 235 m/s,and 40.30 GPa,respectively,while DNFP presents relatively lower detonation velocity (8 811 m/s)and detonation pressure (36.27 GPa).As monopropellants,specific impulse of DNFP,DNFOP and DNPTDO are higher than that of RDX by 97.6,120.6 and 140.6 N·s/kg,respectively.%设计了3种二硝基芳杂环并哒嗪化合物：4，7-二硝基呋咱并[3，4-d]哒嗪（DNFP）、4，7-二硝基氧化呋咱并[3，4-d]哒嗪（DNFOP）和5，8-二硝基哒嗪并[4，5-e][1，2，3，4]-四嗪1，3-二氧化物（DNPTDO）。采用密度泛函理论的 B3LYP 方法在6-31G**基组水平上对3种化合物的构型进行了全优化，计算了 Wiberg 键级、键离解能（BDE）和静电势参数、理论密度和固相生成焓，用 Kamlet-Jacobs 公式和最小自由能法计算了爆速、爆压和能量特性。结果表明，DNFP 的键离解能为216．13 kJ/mol，密度为1．903 g/cm3，爆速为8811 m/s，爆压为36．27 GPa，未达到高能量密度化合物的标准；DNFOP 和 DNPTDO 的键离解能分别为80．37和208．59 kJ/mol，密度分别为1．939和1．942
Roy, Subhadip; Oyarzabal, Itziar; Vallejo, Julia; Cano, Joan; Colacio, Enrique; Bauza, Antonio; Frontera, Antonio; Kirillov, Alexander M; Drew, Michael G B; Das, Subrata
2016-09-06
A mononuclear cobalt(II) complex [Co(3,5-dnb)2(py)2(H2O)2] {3,5-Hdnb = 3,5-dinitrobenzoic acid; py = pyridine} was isolated in two polymorphs, in space groups C2/c (1) and P21/c (2). Single-crystal X-ray diffraction analyses reveal that 1 and 2 are not isostructural in spite of having equal formulas and ligand connectivity. In both structures, the Co(II) centers adopt octahedral {CoN2O4} geometries filled by pairs of mutually trans terminal 3,5-dnb, py, and water ligands. However, the structures of 1 and 2 disclose distinct packing patterns driven by strong intermolecular O-H···O hydrogen bonds, leading to their 0D→2D (1) or 0D→1D (2) extension. The resulting two-dimensional layers and one-dimensional chains were topologically classified as the sql and 2C1 underlying nets, respectively. By means of DFT theoretical calculations, the energy variations between the polymorphs were estimated, and the binding energies associated with the noncovalent interactions observed in the crystal structures were also evaluated. The study of the direct-current magnetic properties, as well as ab initio calculations, reveal that both 1 and 2 present a strong easy-plane magnetic anisotropy (D > 0), which is larger for the latter polymorph (D is found to exhibit values between +58 and 117 cm(-1) depending on the method). Alternating current dynamic susceptibility measurements show that these polymorphs exhibit field-induced slow relaxation of the magnetization with Ueff values of 19.5 and 21.1 cm(-1) for 1 and 2, respectively. The analysis of the whole magnetic data allows the conclusion that the magnetization relaxation in these polymorphs mainly takes place through a virtual excited state (Raman process). It is worth noting that despite the notable difference between the supramolecular networks of 1 and 2, they exhibit almost identical magnetization dynamics. This fact suggests that the relaxation process is intramolecular in nature and that the virtual state involved in the
Institute of Scientific and Technical Information of China (English)
范春珍; 臧华平; 牧凯军
2016-01-01
Bimetallic nanoparticles exhibied optical properties that differ significantly from those of the bulk material due to hybrid surface plasmon resonance. With the quasi-static approximation, the behavior of the light propagation was investigated. Resorting to the Bruggernan theory, the extinction coefficient, absorption coefficient, reflection, transmittance and refraction were theoretically investigated. Our results showed that by tuning the volume fraction of the metallic nanoparticles, its resonant peak could be tuned as accordingly. This calculation method can significantly improve the computing efficiency.%双金属合金纳米颗粒基于杂化的表面等离子共振特性表现出优异的光学性能，因而利用Brug-german理论研究双金属合金的光学调控特性，在准静态近似下计算双金属合金的光学消光系数、吸收系数、反射率和透射率，通过调节复合双金属合金的体积分数，体系的共振峰得到有效调节。结果表明，该研究方法是一种简单、快速、有效的方法，不需要求解复杂的微分方程，仅仅通过改变体积分数和颗粒周围的介电常数即可以实现光谱的调节。
铁路隧道列车相会时活塞风理论计算%Theoretical calculation of piston-wind caused by train meeting in railway tunnel
Institute of Scientific and Technical Information of China (English)
田峰; 王海桥; 朱祝龙
2012-01-01
由于占据了部分隧道空间,列车在运行时会产生活塞作用效应,列车周围的流场和压力场均发生变化,造成了隧道与外部空间的空气交换.为了找出列车相会时活塞效应的关键因素,根据粘性流体力学的非稳定流理论,分析了列车在隧道内的运行情况,采用相对坐标法建立了列车相会时的活塞风数学模型,提出了在自然风速影响下列车相会以及减速相会时的活塞风速计算方法.结果表明,列车活塞效应的影响因素主要有隧道净空尺寸、自然风速和阻塞比等.%For taking part space of tunnel by train, the change of flow and pressure field which is caused by piston effect of train leaded to the exchange of airflow between tunnel and outside. In order to find out the key factors of piston effect, according to the unsteady flow theory of viscous fluid mechanics, train operation in tunnel is analyzed in the paper. Basing on relative coordinate method mathematical model of piston effect is founded, and theoretical calculation of piston wind caused by train meeting under the influence of natural wind is put forward. Results indicated that blockage ratio, tunnel cross - section, train speed and natural wind speed are the major factors of piston wind.
Energy Technology Data Exchange (ETDEWEB)
Nguyen, Son (ed.) [Canadian Nuclear Safety Commission (Canada); Lanru Jing (ed.) [Royal Institute of Technology, Stockholm (Sweden); Boergesson, Lennart [Clay Technology AB, Lund (Sweden); Chijimatzu, Masakazu [Hazama Corporation (Japan); Jussila, Petri [Helsinki Univ. of Technology, Helsinki (Finland); Rutqvist, Jonny [Lawrence Berkeley National Laboratory CA (United States)
2007-02-15
The DECOVALEX-THMC project is an ongoing international co-operative project that was stared in 2004 to support the development of mathematical models of coupled Thermal (T), Hydrological (H), Mechanical (M) and Chemical (C) processes in geological media for siting potential nuclear fuel waste repositories. The general objective is to characterise and evaluate the coupled THMC processes in the near field and far field of a geological repository and to assess their impact on performance assessment: - during the three phases of repository development: excavation phase, operation phase and post-closure phase; - for three different rocks types: crystalline, argillaceous and tuff; - with specific focus on the issues of: Excavation Damaged Zone (EDZ), permanent property changes of rock masses, and glaciation and permafrost phenomena. The project involves a large number of research teams supported by radioactive waste management agencies or governmental regulatory bodies in Canada, China, Finland, France, Germany, Japan, Sweden and USA, who conducted advanced studies and numerical modelling of coupled THMC processes under five tasks. This report presents the definition of the first phase, Task A-1, of the Task A of the project. The task is a working example of how interaction between THMC modelling and SA analysis could be performed. Starting with the technical definition of the Task A, the report presents the results of preliminary THM calculations with a purpose of an initial appreciation of the phenomena and material properties that must be better understood in subsequent phases. Many simplifications and assumptions were introduced and the results should be considered under these assumptions. Based on the evaluation of the multiple teams' results, a few points of concern were identified that may guide the successive phases of Task A studies: 1. The predicted maximum total stress in the MX-80 bentonite could slightly exceed the 15 MPa design pressure for the
Institute of Scientific and Technical Information of China (English)
谢小鹏; 曹立峰; 曾建豪
2015-01-01
According to the friction resistance decrease of van body surface observed by experiments in the presence of air film, three theories, namely the thickened boundary layer theory , the mixed deceleration theory and the thickened boundary layer-mixed deceleration theory , are put forward to explore the mechanism of air-film drag re-duction , and a model to calculate the friction resistance of van body surface in the presence of air film is estab -lished .Then , the friction resistances of van body surface with and without air film are qualitatively compared and analyzed , respectively .The results show that the friction resistance decreases in the presence of air film , which is consistent with the previous experimental results obtained by the authors .This research provides a theoretical foun-dation for the practical application of air-film drag reduction of van body surface .%针对气膜条件下厢式运输车厢体表面摩擦阻力减小的实验结果，分别提出边界层加厚理论、混合降速理论、边界层加厚－混合降速理论3种理论来研究空气介质中空气膜的减阻机理，建立了气膜条件下厢式运输车厢体表面气流摩擦阻力计算模型，定性对比分析了厢体表面在有气膜和无气膜条件下各自所受到的气流摩擦阻力。结果表明，有气膜时摩擦阻力减小，这一结果与笔者前期的实验研究结果趋于一致，为气膜减阻在厢体表面减阻中的实际应用提供了理论基础。
Mikeš, Daniel
2010-05-01
Theoretical geology Present day geology is mostly empirical of nature. I claim that geology is by nature complex and that the empirical approach is bound to fail. Let's consider the input to be the set of ambient conditions and the output to be the sedimentary rock record. I claim that the output can only be deduced from the input if the relation from input to output be known. The fundamental question is therefore the following: Can one predict the output from the input or can one predict the behaviour of a sedimentary system? If one can, than the empirical/deductive method has changes, if one can't than that method is bound to fail. The fundamental problem to solve is therefore the following: How to predict the behaviour of a sedimentary system? It is interesting to observe that this question is never asked and many a study is conducted by the empirical/deductive method; it seems that the empirical method has been accepted as being appropriate without question. It is, however, easy to argument that a sedimentary system is by nature complex and that several input parameters vary at the same time and that they can create similar output in the rock record. It follows trivially from these first principles that in such a case the deductive solution cannot be unique. At the same time several geological methods depart precisely from the assumption, that one particular variable is the dictator/driver and that the others are constant, even though the data do not support such an assumption. The method of "sequence stratigraphy" is a typical example of such a dogma. It can be easily argued that all the interpretation resulting from a method that is built on uncertain or wrong assumptions is erroneous. Still, this method has survived for many years, nonwithstanding all the critics it has received. This is just one example of the present day geological world and is not unique. Even the alternative methods criticising sequence stratigraphy actually depart from the same
Theoretical Delay Time Distributions
Nelemans, Gijs; Bours, Madelon
2012-01-01
We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of type Ia supernova progenitors. We also compare the results of the different research groups and conclude that although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this cannot explain all the differences.
Theoretical Delay Time Distributions
Nelemans, Gijs; Toonen, Silvia; Bours, Madelon
2013-01-01
We briefly discuss the method of population synthesis to calculate theoretical delay time distributions of Type Ia supernova progenitors. We also compare the results of different research groups and conclude that, although one of the main differences in the results for single degenerate progenitors is the retention efficiency with which accreted hydrogen is added to the white dwarf core, this alone cannot explain all the differences.
Joos, Georg
1986-01-01
Among the finest, most comprehensive treatments of theoretical physics ever written, this classic volume comprises a superb introduction to the main branches of the discipline and offers solid grounding for further research in a variety of fields. Students will find no better one-volume coverage of so many essential topics; moreover, since its first publication, the book has been substantially revised and updated with additional material on Bessel functions, spherical harmonics, superconductivity, elastomers, and other subjects.The first four chapters review mathematical topics needed by theo
ANALYTICAL METHODS FOR CALCULATING FAN AERODYNAMICS
Directory of Open Access Journals (Sweden)
Jan Dostal
2015-12-01
Full Text Available This paper presents results obtained between 2010 and 2014 in the field of fan aerodynamics at the Department of Composite Technology at the VZLÚ aerospace research and experimental institute in Prague – Letnany. The need for rapid and accurate methods for the preliminary design of blade machinery led to the creation of a mathematical model based on the basic laws of turbomachine aerodynamics. The mathematical model, the derivation of which is briefly described below, has been encoded in a computer programme, which enables the theoretical characteristics of a fan of the designed geometry to be determined rapidly. The validity of the mathematical model is assessed continuously by measuring model fans in the measuring unit, which was developed and manufactured specifically for this purpose. The paper also presents a comparison between measured characteristics and characteristics determined by the mathematical model as the basis for a discussion on possible causes of measured deviations and calculation deviations.
Stöltzner, Michael
Answering to the double-faced influence of string theory on mathematical practice and rigour, the mathematical physicists Arthur Jaffe and Frank Quinn have contemplated the idea that there exists a `theoretical' mathematics (alongside `theoretical' physics) whose basic structures and results still require independent corroboration by mathematical proof. In this paper, I shall take the Jaffe-Quinn debate mainly as a problem of mathematical ontology and analyse it against the backdrop of two philosophical views that are appreciative towards informal mathematical development and conjectural results: Lakatos's methodology of proofs and refutations and John von Neumann's opportunistic reading of Hilbert's axiomatic method. The comparison of both approaches shows that mitigating Lakatos's falsificationism makes his insights about mathematical quasi-ontology more relevant to 20th century mathematics in which new structures are introduced by axiomatisation and not necessarily motivated by informal ancestors. The final section discusses the consequences of string theorists' claim to finality for the theory's mathematical make-up. I argue that ontological reductionism as advocated by particle physicists and the quest for mathematically deeper axioms do not necessarily lead to identical results.
Institute of Scientific and Technical Information of China (English)
陈宗平; 徐金俊; 梁红飞; 陈宇良
2012-01-01
Industrial tanks are widely used in various petrochemical industries. Located in an indus-trial area in Nanning, Guangxi, the foundation ring walls of twelve newly built huge alcohol fermen-tation tanks were cracked massively when a trial operation began. There were many vertical cracks, together with a large angle warping between the steel tank and the ring wall, which had a negative impact on the production of the factory. In order to explore the cause of such accidents, the perform-ance indicators, such as concrete strength, state of cracks, steel condition and its cover thickness, tank verticality, concrete surface defects and so on, were tested on site. The No. 1 fermentation tank was analyzed as a typical example. Computer simulation and traditional theoretical approaches were applied to calculate the bearing capacity of different cases. It is concluded that the ring walls above the ground elevation faced lateral pressure induced by the internal sand may lead to the crack. Or it is most likely that the internal sand is not dense and when the water was injected into the steel tank, the tank was warped. This may result in the bottom steel slab to become deformed and to push the sand, leading to too much larger tensile stress in the ring walls to crack.%工业储罐广泛应用于各类石油化工行业.位于广西南宁市某工业区的12个巨型酒精发酵罐在试运营阶段曾发生了基础环墙的群体性开裂,产生大量的竖向裂缝,同时钢液罐与环墙发生较大角度的翘曲,影响了企业的后续生产.为了探究此类工程事故的内在原因,通过现场检测获取发酵罐与基础环墙的各项性能指标,分析了各罐的环墙混凝土强度、裂缝状况、钢筋保护层厚度及罐体垂直度等宏观特性；并以具有代表性的1号发酵罐为例,运用计算机数值模拟以及传统理论方法进行不同工况组合下的承载力验算.分析结果表明:事故由两个方面原因所致,其一是
Yu, Dong; Jiang, Lan; Wang, Feng; Qu, Liangti; Lu, Yongfeng
2016-05-01
Time-dependent density functional theory-based first-principles calculations have been used to study the ionization process and electron excitation. The results show that the number of excited electrons follows the power law σ k I k at peak intensities of I key role. The multiphoton absorption cross section of α-quartz σ k is further calculated to be 3.54 × 1011 cm-3 ps-1 (cm2/TW)6. Using the plasma model, the theoretical results of the damage threshold fluences are consistent with the experimental data, which validates the calculated value of multiphoton absorption cross section. By employing the calculated cross section value in the plasma model, the damage threshold fluences are theoretically estimated, being consistent with the experimental data, which validates the calculated value of multiphoton absorption cross section. The preliminary multiscale model shows great potential in the simulation of laser processing.
Theoretical Physics 1. Theoretical Mechanics
Energy Technology Data Exchange (ETDEWEB)
Dreizler, Reiner M.; Luedde, Cora S. [Frankfurt Univ. (Germany). Inst. fuer Theoretische Physik
2010-07-01
After an introduction to basic concepts of mechanics more advanced topics build the major part of this book. Interspersed is a discussion of selected problems of motion. This is followed by a concise treatment of the Lagrangian and the Hamiltonian formulation of mechanics, as well as a brief excursion on chaotic motion. The last chapter deals with applications of the Lagrangian formulation to specific systems (coupled oscillators, rotating coordinate systems, rigid bodies). The level of this textbook is advanced undergraduate. The authors combine teaching experience of more than 40 years in all fields of Theoretical Physics and related mathematical disciplines and thorough knowledge in creating advanced eLearning content. The text is accompanied by an extensive collection of online material, in which the possibilities of the electronic medium are fully exploited, e.g. in the form of applets, 2D- and 3D-animations. (orig.)
Directory of Open Access Journals (Sweden)
Barney G. Glaser, Ph.D., Hon. Ph.D.
2009-11-01
Full Text Available Theoretical sorting has brought the analyst to the point of pent-up pressure to write: to see the months of work actualized in a “piece.” But this is only a personal pressure. The goal of grounded theory methodology, above all is to offer the results to the public, usually through one or more publications. We will focus on writing for publication, which is the most frequent way that the analyst can tell how people are “buying” what really matters in sociology, or in other fields.Both feedback on and use of publications will be the best evaluation of the analyst’s grounded theory. It will be his main source or criticism, constructive critique, and frequently of career rewards. In any case, he has to write to expand his audience beyond the limited number of close colleagues and students. Unless there is a publication, his work will be relegated to limited discussion, classroom presentation, or even private fantasy. The rigor and value of grounded theory work deserves publication. And many analysts have a stake in effecting wider publics, which makes their substantive grounded theory count.
Directory of Open Access Journals (Sweden)
Borkowski Andrzej
2015-12-01
Full Text Available The paper presents a summary of research activities concerning theoretical geodesy performed in Poland in the period of 2011-2014. It contains the results of research on new methods of the parameter estimation, a study on robustness properties of the M-estimation, control network and deformation analysis, and geodetic time series analysis. The main achievements in the geodetic parameter estimation involve a new model of the M-estimation with probabilistic models of geodetic observations, a new Shift-Msplit estimation, which allows to estimate a vector of parameter differences and the Shift-Msplit(+ that is a generalisation of Shift-Msplit estimation if the design matrix A of a functional model has not a full column rank. The new algorithms of the coordinates conversion between the Cartesian and geodetic coordinates, both on the rotational and triaxial ellipsoid can be mentioned as a highlights of the research of the last four years. New parameter estimation models developed have been adopted and successfully applied to the control network and deformation analysis.
Borkowski, Andrzej; Kosek, Wiesław
2015-12-01
The paper presents a summary of research activities concerning theoretical geodesy performed in Poland in the period of 2011-2014. It contains the results of research on new methods of the parameter estimation, a study on robustness properties of the M-estimation, control network and deformation analysis, and geodetic time series analysis. The main achievements in the geodetic parameter estimation involve a new model of the M-estimation with probabilistic models of geodetic observations, a new Shift-Msplit estimation, which allows to estimate a vector of parameter differences and the Shift-Msplit(+) that is a generalisation of Shift-Msplit estimation if the design matrix A of a functional model has not a full column rank. The new algorithms of the coordinates conversion between the Cartesian and geodetic coordinates, both on the rotational and triaxial ellipsoid can be mentioned as a highlights of the research of the last four years. New parameter estimation models developed have been adopted and successfully applied to the control network and deformation analysis. New algorithms based on the wavelet, Fourier and Hilbert transforms were applied to find time-frequency characteristics of geodetic and geophysical time series as well as time-frequency relations between them. Statistical properties of these time series are also presented using different statistical tests as well as 2nd, 3rd and 4th moments about the mean. The new forecasts methods are presented which enable prediction of the considered time series in different frequency bands.
Preliminary designs: passive solar manufactured housing. Technical status report
Energy Technology Data Exchange (ETDEWEB)
1980-05-12
The criteria established to guide the development of the preliminary designs are listed. Three preliminary designs incorporating direct gain and/or sunspace are presented. Costs, drawings, and supporting calculations are included. (MHR)
Energy Technology Data Exchange (ETDEWEB)
Hellmann, Robert
2009-06-16
Thermophysical properties of the pure gases helium, neon, methane and water vapor were calculated for low densities over wide temperature ranges. Statistical thermodynamics was used for the determination of the pressure virial coefficients. The kinetic theory of gases was utilized for the calculation of the transport and relaxation properties. So far kinetic theory was limited to linear molecules and has now been extended to molecules of arbitrary geometry to enable calculations on methane and water vapor. The interaction potentials, which are needed for all computations, were determined for helium, neon and methane from the supermolecular approach using quantum chemical ab initio methods. For water the interaction potentials were taken from the literature. The calculated values of the thermophysical properties for the four gases show very good agreement with the best experimental data. At very low and very high temperatures the theoretical values are more accurate than experimental data. (orig.)
Institute of Scientific and Technical Information of China (English)
贾继峰; 张继生
2011-01-01
The index of stopping power of inner-support anti-sliding device could be gained mainly through the free rolling experiment on dispatching line. In order to give theoretical support for the design of inner-support anti-sliding device,the authors establish calculation model by taking T·TK-92 controllable stopping device as example,calculate the major technical parameters and stopping power,study the theoretical calculation method for calculating the stopping power of inner-support anti-sliding device. The results show that the calculation values are very similar to those gained by experiment,the errors are in the acceptable ranges.%内撑式停车防溜器的制动能力指标主要通过调车线溜放试验获取,为给内撑式停车防溜器设计提供理论支持,以T.TK-92型可控停车器为例,建立计算模型,计算主要技术参数和制动能力,研究内撑式停车防溜器制动能力的理论计算方法。结果表明,计算所得数值与车辆溜放制动实测数值基本一致,在允许误差范围内。
National Oceanic and Atmospheric Administration, Department of Commerce — Declination is calculated using the current International Geomagnetic Reference Field (IGRF) model. Declination is calculated using the current World Magnetic Model...
Theoretical Mechanics Theoretical Physics 1
Dreizler, Reiner M
2011-01-01
After an introduction to basic concepts of mechanics more advanced topics build the major part of this book. Interspersed is a discussion of selected problems of motion. This is followed by a concise treatment of the Lagrangian and the Hamiltonian formulation of mechanics, as well as a brief excursion on chaotic motion. The last chapter deals with applications of the Lagrangian formulation to specific systems (coupled oscillators, rotating coordinate systems, rigid bodies). The level of this textbook is advanced undergraduate. The authors combine teaching experience of more than 40 years in all fields of Theoretical Physics and related mathematical disciplines and thorough knowledge in creating advanced eLearning content. The text is accompanied by an extensive collection of online material, in which the possibilities of the electronic medium are fully exploited, e.g. in the form of applets, 2D- and 3D-animations. - A collection of 74 problems with detailed step-by-step guidance towards the solutions. - A col...
Theoretical solid state physics
Haug, Albert
2013-01-01
Theoretical Solid State Physics, Volume 1 focuses on the study of solid state physics. The volume first takes a look at the basic concepts and structures of solid state physics, including potential energies of solids, concept and classification of solids, and crystal structure. The book then explains single-electron approximation wherein the methods for calculating energy bands; electron in the field of crystal atoms; laws of motion of the electrons in solids; and electron statistics are discussed. The text describes general forms of solutions and relationships, including collective electron i
Institute of Scientific and Technical Information of China (English)
刘丽梅; 夏建才; 刘永
2012-01-01
运用B—W法确定煤矿许用电雷管药剂的爆炸反应方程式,用盖斯定律计算定容爆热,用加权法计算爆炸产物的摩尔定容热容,研究计算得出采用冰晶石作消焰剂的煤矿许用电雷管药剂常见配方的爆热、爆温数据,并对计算结果进行了分析与讨论.计算结果显示随着冰晶石含量的增加,煤矿许用电雷管药剂的爆热、爆温分别呈现下降趋势.%Based on B-W rule the explosion reaction equation of composition in permissible electric detonator was established, the constant volume explosion heat of composition in permissible electric detonator was calculated based on Hess law, and specific heat capacity (SHC) of explosion products were calculated with the method of weighted averages. The constant volume explosion heat and explosion temperature were calculated for the composition in permissible electric detonator which contain sodium aluminum fluoride as flame-depressant. Calculation results show that the explosion heat and explosion temperature of composition in permissible electric detonator respectively decrease as the content of sodium aluminum fluoride increased.
Structure and content of fencers’ theoretical training
Directory of Open Access Journals (Sweden)
Briskin Y.A.
2013-08-01
Full Text Available The structure and content of the theoretical training in the system of long-term improvement of athletes fencers is identified. Found that the theoretical training athletes selected 1.2-2.0% (initial training, 1,9-2,3% (preliminary stage of basic training, 2.1% (stage specialized basic training, 1, 8% (preparation stage for the highest achievements of the total training load in the annual cycle of training. It is established that there is a wrong approach to the planning of educational material on theoretical training. Under it, information material (by category and blocks presented based on the total phase, rather than individual grade levels. Recommended compensation direction of the individual components of theoretical training athletes: refining the means and methods of theoretical training, structuring of information, implementation of control theoretical training.
Hubbard, W B
2016-01-01
In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen-helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses, and a hydrogen-helium-rich envelope with...
Hubbard, W. B.; Militzer, B.
2016-03-01
In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen-helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses and a hydrogen-helium-rich envelope with approximately three times solar metallicity.
Sychrovský, Vladimír; Sponer, Jirí; Hobza, Pavel
2004-01-21
The calculated intermolecular and intramolecular indirect NMR spin-spin coupling constants and NMR shifts were used for the discrimination between the inner-shell and the outer-shell binding motif of hydrated divalent cations Mg(2+) or Zn(2+) with a guanine base. The intermolecular coupling constants (1)J(X,O6) and (1)J(X,N7) (X = Mg(2+), Zn(2+)) can be unambiguously assigned to the specific inner-shell binding motif of the hydrated cation either with oxygen O6 or with nitrogen N7 of guanine. The calculated coupling constants (1)J(Mg,O6) and (1)J(Zn,O6) were 6.2 and -17.5 Hz, respectively, for the inner-shell complex of cation directly interacting with oxygen O6 of guanine. For the inner-shell coordination of the cation at nitrogen N7, the calculated coupling constants (1)J(Mg,N7) and (1)J(Zn,N7) were 5.6 and -36.5 Hz, respectively. When the binding of the cation is water-mediated, the coupling constant is zero. To obtain reliable shifts in NMR parameters, hydrated guanine was utilized as the reference state. The calculated change of NMR spin-spin coupling constants due to the hydration and coordination of the cation with guanine is caused mainly by the variation of Fermi-contact coupling contribution while the variation of diamagnetic spin-orbit, paramagnetic spin-orbit, and spin-dipolar coupling contributions is small. The change of s-character of guanine sigma bonding, sigma antibonding, and lone pair orbitals upon the hydration and cation coordination (calculated using the Natural Bond Orbital analysis) correlates with the variation of the Fermi-contact term. The calculated NMR shifts delta(N7) of -15.3 and -12.2 ppm upon the coordination of Mg(2+) and Zn(2+) ion are similar to the NMR shift of 19.6 ppm toward the high field measured by Tanaka for N7 of guanine upon the coordination of the Cd(2+) cation (Tanaka, Y.; Kojima, C.; Morita, E. H.; Kasai. Y.; Yamasaki, K.; Ono, A.; Kainosho, M.; Taira, K. J. Am. Chem. Soc. 2002, 124, 4595-4601). The present data
Gökşen, Umut Salgın; Alpaslan, Yelda Bingöl; Kelekçi, Nesrin Gökhan; Işık, Şamil; Ekizoğlu, Melike
2013-05-01
1-[2-(5-Chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3-methoxyphenyl)-4,5-dihydro-(1H)-pyrazole (5a), 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-phenyl-5-(3,4-dimethoxyphenyl)-4,5-dihydro-(1H)-pyrazole (5b) and 1-[2-(5-chloro-2-benzoxazolinone-3-yl)acetyl]-3-(4-methylphenyl)-5-(2,3-dimethoxyphenyl)-4,5-dihydro-(1H)-pyrazole (5c) were synthesized. The crystal and molecular structures of the compounds 5a, 5b and 5c were determined by elemental analyses, IR, 1H NMR, ESI-MS and single-crystal X-ray diffraction. DFT method with 6-31G(d,p) basis set was used to calculate the optimized geometrical parameters, vibrational frequencies and chemical shift values. The calculated vibrational frequencies and chemical shift values were compared with experimental IR and 1H NMR values. The results represented that there was a good agreement between experimental and calculated values of the compounds 5a-5c. In addition, DFT calculations of the compounds, molecular electrostatic potentials (MEPs) and frontier molecular orbitals were performed at B3LYP/6-31G(d,p) level of theory. Furthermore, compounds were tested against three Gram-positive bacteria: Staphylococcus aureus ATCC 29213 (American Type Culture Collection), methicillin resistant S. aureus (MRSA) ATCC 43300 and Enterococcus faecalis ATCC 29212; two Gram negative bacteria: Escherichia coli ATCC 25922 and Pseudomonas aeruginosa ATCC 27853; and three fungi: Candida albicans ATCC 90028, Candida krusei ATCC 6258 and Candida parapsilosis ATCC 90018. In general, all of the compounds were found to be slightly active against tested microorganisms.
Institute of Scientific and Technical Information of China (English)
田晓明; 冯永振
2001-01-01
本文根据激光汽化兼热杀癌肿瘤的理论模型〔1，2〕，对三种常见热效应激光进行了理论计算和结果对比，讨论了在较大汽化域情况下尽可能减少照射治疗时间的应用方法和措施，为激光治疗较大肿瘤提供具体理论参考数据。%Based on the theoretical models of vaporizing and heat-killing therapy of cancer with laser,the theoretical calculations of three common thermal-effect lasers have been made,and the results are shown and compared in this paper.We discuss on the applied methods to get the irradiating time as short as possible under more large vaporizing area.These theoretical calculated data will be valuable for reference.
Institute of Scientific and Technical Information of China (English)
王海军; 柳敏燕; 高娟
2013-01-01
为了解决传统的采用一元线性回归法计算农用地理论单产和可实现单产的局限性，该文将遗传算法和支持向量回归机理论应用于农用地产能核算，构建理论单产和可实现单产核算模型。通过建立样点分等因素质量分与理论单产的遗传算法支持向量回归机（genetic algorithm-support vector machine，GA-SVM）模型进行理论单产预测；建立样点分等因素质量分和利用系数之积与可实现单产的遗传算法支持向量回归机模型进行可实现单产预测。以广东省揭西县产能核算为例，分别采用GA-SVM模型和一元线性回归模型测算，并将测算结果进行对比分析。研究结果证明，GA-SVM对于理论单产和可实现单产的测算精度更高，适于单个样本值的预测，可以作为农用地产能核算的一种新方法。%Grain security is a complex, resource-intensive problem being addressed by governments, international organizations, and scientific community. Ensuring adequate grain supply is vital to the survival of humanity, and its key lies in improving total agricultural land productivity. The level of the comprehensive productive capacity of agriculture is directly related to the effective supply of grains. In 2011, China conducted a nationwide agricultural productivity survey in order to improve its overall capacity, protect farm quality, and accomplish the National Food Security Strategy. The core components of agricultural land productivity calculations are the theoretical and accessible yields. The theoretical yield calculation was traditionally performed by establishing samples’ linear regression models between natural level index and theoretical yield. The accessible yield, meanwhile, was performed by establishing samples’ linear regression models between usage level index and accessible yield. Then the agricultural land productivity can be calculated by the yield multiplying with the total area of
Transfer Area Mechanical Handling Calculation
Energy Technology Data Exchange (ETDEWEB)
B. Dianda
2004-06-23
This calculation is intended to support the License Application (LA) submittal of December 2004, in accordance with the directive given by DOE correspondence received on the 27th of January 2004 entitled: ''Authorization for Bechtel SAX Company L.L. C. to Include a Bare Fuel Handling Facility and Increased Aging Capacity in the License Application, Contract Number DE-AC28-01R W12101'' (Arthur, W.J., I11 2004). This correspondence was appended by further Correspondence received on the 19th of February 2004 entitled: ''Technical Direction to Bechtel SAIC Company L.L. C. for Surface Facility Improvements, Contract Number DE-AC28-OIRW12101; TDL No. 04-024'' (BSC 2004a). These documents give the authorization for a Fuel Handling Facility to be included in the baseline. The purpose of this calculation is to establish preliminary bounding equipment envelopes and weights for the Fuel Handling Facility (FHF) transfer areas equipment. This calculation provides preliminary information only to support development of facility layouts and preliminary load calculations. The limitations of this preliminary calculation lie within the assumptions of section 5 , as this calculation is part of an evolutionary design process. It is intended that this calculation is superseded as the design advances to reflect information necessary to support License Application. The design choices outlined within this calculation represent a demonstration of feasibility and may or may not be included in the completed design. This calculation provides preliminary weight, dimensional envelope, and equipment position in building for the purposes of defining interface variables. This calculation identifies and sizes major equipment and assemblies that dictate overall equipment dimensions and facility interfaces. Sizing of components is based on the selection of commercially available products, where applicable. This is not a specific recommendation for the future use
Institute of Scientific and Technical Information of China (English)
马堃; 褚园; 焦铮; 谢国秋
2013-01-01
以多电子原子精细结构哈密顿的球张量形式为基础,借助不可约张量理论,对铍原子1s22snp(n=2～6) 3p态精细结构(包括自旋-轨道相互作用、自旋-其它轨道相互作用和自旋-自旋相互作用)进行了具体地计算,并将计算结果与文献结果进行了比较,符合地较好.同时,计算了1s22snp(n=2～6)3p态精细结构参数A和B的值.%Based on the tensor expression of the fine-structure Hamiltonian for many-electron atoms,and with the help of irreducible tensor theory,the fine-structure energies (including spin-orbit interaction,spin-other-orbit interaction and the spin-spin interaction) of the 1s22snp3p state in beryllium atom have been calculated.The results are in close agreement with the experimental data.Meanwhile,parameters of the fine-structure have been calculated further.
Institute of Scientific and Technical Information of China (English)
林大能; 邓新文
2001-01-01
In this paper,the development of study on blasting cut hight calculation in demolishing building by controlled blasting is introduced．Based on energy conversion theory,the criteria determing minimum blasting cut height are given．The criteria are simplfied in terms of theory of progression．The practica lmethod of calculating blasting cut hei ght is given．The analysis of practical examplesi llustrated that the practicalc alulation method is of practical signifi cance for demolishing building by contro lled blasting．%介绍了爆破缺口高度的研究现状,以能量转化理论为基础给出了确定爆破缺口最小范围的判据,借助级数理论对判据进行了简化,得出了爆破缺口高度实用理论计算方法。通过实例计算分析,证明了文中的实用理论计算方法对工程实践有指导意义。
Institute of Scientific and Technical Information of China (English)
何彪; 何建新; 易有根; 江少恩; 郑志坚
2011-01-01
在David Botz分析模型的基础上,综合考虑正电子及电子碰撞电离的库仑效应和电子交换效应,引入离子效应和相对论效应修正因子,计算了Ag,In,Sn原子的L壳层电离截面.计算结果表明,引入了修正因子的计算结果明显优于平面波波恩近似和扭曲波波恩近似的计算结果,并和最近文献的实验值符合得较好.其计算结果可为激光等离子体模拟提供准确参数.%Based on the analytical formulas of David Botz, considering the Coulomb effect and exchange effect in the ionization by positron and electron impact, the total cross sections of positron-impact Lshell ionization of Ag? In, Sn atomic are calculated by incorporating both ionic and relativistic corrections in it. In comparison with the quantum mechanical predictions of plane-wave and distorted-wave Born approximations, it is found that the improved analytical formulas are in better agreement with the experimental results. The calculated results can be used to simlate the laser plasma.
Wang, Hongjuan; Han, Genquan; Wang, Yibo; Peng, Yue; Liu, Yan; Zhang, Chunfu; Zhang, Jincheng; Hu, Shengdong; Hao, Yue
2016-04-01
In this work, a lattice-matched SiGeSn/GeSn heterostructure p-channel tunneling field-effect transistor (hetero-PTFET) with a type-II staggered tunneling junction (TJ) is investigated theoretically. Lattice matching and type-II band alignment at the Γ-point is obtained at the SiGeSn/GeSn interface by tuning Sn and Si compositions. A steeper subthreshold swing (SS) and a higher on state current (I ON) are demonstrated in SiGeSn/GeSn hetero-PTFET than in GeSn homo-PTFET. Si0.31Ge0.49Sn0.20/Ge0.88Sn0.12 hetero-PTFET achieves a 2.3-fold higher I ON than Ge0.88Sn0.12 homo-PTFET at V DD of 0.3 V. Hetero-PTFET achieves a more abrupt hole profile and a higher carrier density near TJ than the homo-PTFET, which contributes to the significantly enhanced band-to-band tunneling (BTBT) rate and tunneling current in hetero-PTFET.
Energy Technology Data Exchange (ETDEWEB)
Otmani, R
1998-03-01
The Nb{sub 3}Sn ITER-type wire is made up of 19 sub-elements and 162 filaments compose each sub-element. The calculation of the loss by coupling current inside a wire follows 2 stages: first we evaluate the loss due to the mutual interaction between filaments inside a sub-element then we calculate the loss due to the coupling between sub-elements of the wire. In both calculations the hypothesis of stationary states is made and we assume that the filaments are not saturated. (A.C.) 9 refs.
A theoretical and spectroscopic study of conformational structures of piroxicam
Souza, Kely Ferreira de; Martins, José A.; Pessine, Francisco B. T.; Custodio, Rogério
2010-02-01
Piroxicam (PRX) has been widely studied in an attempt to elucidate the causes and mechanisms of its side effects, mainly the photo-toxicity. In this paper fluorescence spectra in non-protic solvents and different polarities were carried out along with theoretical calculations. Preliminary potential surfaces of the keto and enol forms were obtained at AM1 level of theory providing the most stable conformers, which had their structure re-optimized through the B3LYP/CEP-31G(d,p) method. From the optimized structures, the electronic spectra were calculated using the TD-DFT method in vacuum and including the solvent effect through the PCM method and a single water molecule near PRX. A new potential surface was constructed to the enol tautomer at DFT level and the most stable conformers were submitted to the QST2 calculations. The experimental data showed that in apolar media, the solution fluorescence is raised. Based on conformational analysis for the two tautomers, keto and enol, the results indicated that the PRX-enol is the main tautomer related to the drug fluorescence, which is reinforced by the spectra results, as well as the interconvertion barrier obtained from the QST2 calculations. The results suggest that the PRX one of the enol conformers presents great possibility of involvement in the photo-toxicity mechanisms.
Hansen, Inger M J; Emamifar, Amir; Andreasen, Rikke A; Antonsen, Steen
2017-01-01
Disease Activity Score in 28 joints (DAS28) is commonly used to evaluate disease activity of rheumatoid arthritis (RA) and is a guide to treatment decision.The aim of this study was to evaluate the impact of lower reporting limit for C-reactive protein (CRP), with respect to intraindividual biological variability, on the calculation of DAS28 and subsequent patient classification.This study consists of 2 sections: a theoretical consideration discussing the performance of CRP in calculating DAS28 taking intraindividual biological variation and lower reporting limit for CRP into account and a cross-sectional study of RA patients applying our theoretical results. Therefore, we calculated DAS28 twice, with the actual CRP values and CRP = 9 mg/L, the latter to elucidate the positive effects of reducing the lower reporting limit of CRP from <10 to <3 mg/L.Lower-reporting limit of <10 mg/L leads to overestimate DAS28. However, reducing lower reporting limit for CRP to <3 mg/L results in optimizing DAS28 calculation. Further lowering of reporting limit for CRP to <3 mg/L does not increase the precision of DAS28 owing to the relatively large intraindividual biological variation.Five hundred twelve patients were included. There was a significant difference between recalculated and patients DAS28 (P < 0.001). One hundred nine patients had DAS28 deviation (compatible to remission to low: 66, low to moderate: 39. and moderate to high: 4).Owing to significant impact of intraindividual biologic variation on DAS28 and patient classification, special attention should be paid to calculate DAS28 when CRP values are within normal range. Furthermore, we conclude that results of different studies evaluating DAS28 and treatment response are not comparable if the reporting limits of CRP are unknown.
Energy Technology Data Exchange (ETDEWEB)
Charifi, Z., E-mail: charifizoulikha@gmail.com [Physics Department, Faculty of Science, University of M' sila, 28000 M' sila (Algeria); Hamad, B. [Physics Department, The University of Jordan, Amman 11942 (Jordan); Physics Department, University of Arkansas, 825 W. Dickson St., Fayetteville, AR 72701 (United States); Baaziz, H. [Physics Department, Faculty of Science, University of M' sila, 28000 M' sila (Algeria); Soyalp, F. [Yüzüncü Yıl University, Faculty of Education, Department of Physics, Van 65080 (Turkey)
2015-11-01
The electronic and magnetic properties of Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn and Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys are investigated using density functional theory (DFT) within a full-potential linearized augmented-plane-wave (FP-LAPW) method. Amongst the systems under investigation, Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys show half metallicity with 100% spin polarization at the Fermi level, however Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn are found to be pseudo-half metals with few minority states at the Fermi level and high spin polarization. The substitution of Si with Sn keeps the magnetic moment constant in Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys, whereas the substitution of Mn with Cr decreases the magnetic moment and degrade the half-metallicity in Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn alloys. The Curie temperature is calculated and it is found to be about 928 K for all Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys, whereas it decreases linearly with x for Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn alloys. The lattices constants, bulk modulii, energy gaps, polarization ratio and density of states are calculated and their variation versus x or y are discussed. - Highlights: • The band structure calculations show that Co{sub 2}MnSn{sub 1−y}Si{sub y} alloys are half-metallic ferromagnets. • The effect of substituting Sn by Si is a slight change in the position of the Fermi level and an increase in the band gap. • For Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn alloys, the results suggest that there is a finite density of states in the minority-spin d band of manganese. • The Co{sub 2}Mn{sub 1−x}Cr{sub x}Sn compounds cannot be classified as half-metallic ferromagnets. • The substitution of Mn with Cr decreases the magnetic moment per formula unit from 5.0 to 4.0µ{sub B}.
Ng, Maggie; Mok, Daniel K W; Lee, Edmond P F; Dyke, John M
2015-03-21
The reaction between atomic chlorine (Cl) and methyl nitrate (CH3ONO2) is significant in the atmosphere, as Cl is a key oxidant, especially in the marine boundary layer, and alkyl nitrates are important nitrogen-containing organic compounds, which are temporary reservoirs of the reactive nitrogen oxides NO, NO2 and NO3 (NOx). Four reaction channels HCl + CH2ONO2, CH3OCl + NO2, CH3Cl + NO3 and CH3O + ClNO2 were considered. The major channel is found to be the H abstraction channel, to give the products HCl + CH2ONO2. For all channels, geometry optimization and frequency calculations were carried out at the M06-2X/6-31+G** level, while relative electronic energies were improved to the UCCSD(T*)-F12/CBS level. The reaction barrier (ΔE(‡)0K) and reaction enthalpy (ΔH(RX)298K) of the H abstraction channel were computed to be 0.61 and -2.30 kcal mol(-1), respectively, at the UCCSD(T*)-F12/CBS//M06-2X/6-31+G** level. Reaction barriers (ΔE(‡)0K) for the other channels are more positive and these pathways do not contribute to the overall reaction rate coefficient in the temperature range considered (200-400 K). Rate coefficients were calculated for the H-abstraction channel at various levels of variational transition state theory (VTST) including tunnelling. Recommended ICVT/SCT rate coefficients in the temperature range 200-400 K are presented for the first time for this reaction. The values obtained in the 200-300 K region are particularly important as they will be valuable for atmospheric modelling calculations involving reactions with methyl nitrate. The implications of the results to atmospheric chemistry are discussed. Also, the enthalpies of formation, ΔHf,298K, of CH3ONO2 and CH2ONO2 were computed to be -29.7 and 19.3 kcal mol(-1), respectively, at the UCCSD(T*)-F12/CBS level.
Zhou, Shiqi; Solana, J. R.
2013-06-01
The first four perturbation coefficients in the expansion of the Helmholtz free energy in power series of the inverse of the reduced temperature for a number of potential models with hard-sphere cores plus core-softened and discontinuous tails are obtained from Monte Carlo simulations. The potential models considered include square-well, double square-well, and square-shoulder plus square-well, with different potential parameters. These simulation data are used to evaluate the performance of a traditional macroscopic compressibility approximation (MCA) for the second order coefficient and a recent coupling parameter series expansion (CPSE) for the first four coefficients. Comprehensive comparison indicates the incapability of the MCA for the second order coefficient in most non-stringent situations, and significance of the CPSE in accurately calculating these four coefficients.
Institute of Scientific and Technical Information of China (English)
马军; 李爱魁; 杨祥军; 刘飞; 张爱芳
2012-01-01
The calculation of shunt current in the all vanadium redox flow battery was described and the calculation process was completed by MATLAB software. The regularity of distribution and effect factors of shunt current was reviewed. In addition, the energy efficiency of 7.5 kW stack was tested. The results show that the center battery has the minimum feed port shunt current and the maximum manifold road shunt current. The modular construction has lower shunt current and higher energy efficiency.%提出了钒电池支路电流计算方法,采用MATLAB软件对不同结构7.5 kW钒电池的支路电流进行了理论计算,分析了支路电流的分布规律及影响因素,并对7.5 kW钒电池进行效率测试,结果表明:支管上的支路电流在电堆中心最小,而总管及主路上的支路电流在电堆中心为最大值,同时单电池个数减少有利于减小支路电流;采用模块化结构的7.5 kW电堆(由2组共30个单电池串联而成,即15个单电池组成一个模块)的支路电流明显降低,其能量效率达到74.4％,高于一体化结构电堆(由1组共30个单电池串联而成,即每组30个单电池)的能量效率(69.4％).
Energy Technology Data Exchange (ETDEWEB)
Chi, Yuan, E-mail: jtext@hust.edu.cn [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China); Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Hu, Chundong [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhuang, Ge [State Key Laboratory of Advanced Electromagnetic Engineering and Technology, Huazhong University of Science and Technology, Wuhan 430074 (China)
2014-02-15
Calorimetric method has been primarily applied for several experimental campaigns to determine the angular divergence of high-current ion source for the neutral beam injection system on the Experimental Advanced Superconducting Tokamak (EAST). A Doppler shift spectroscopy has been developed to provide the secondary measurement of the angular divergence to improve the divergence measurement accuracy and for real-time and non-perturbing measurement. The modified calculation model based on the W7AS neutral beam injectors is adopted to accommodate the slot-type accelerating grids used in the EAST's ion source. Preliminary spectroscopic experimental results are presented comparable to the calorimetrically determined value of theoretical calculation.
Institute of Scientific and Technical Information of China (English)
李晓丽; 李志强; 代博洋; 陈振拓
2012-01-01
The study of earthquake symbols has been an important part of earthquake emergency response. In this paper, we apply the methodology of semeiology and mass communication to analyze the semeiology connotation, main users and the information transmitted of the earthquake symbols. Then We discuss the characteristics of the earthquake symbology system and the basic principles when it is built up. We find that earthquake itself is special and destructive, which eventually leads to the specialty and temporality of the earthquake symbol. With consideration of the principles of applicability, importance and generality followed, we finally propose a kind of theoretical framework of the earthquake symbology system, which offers reference for the further development of the earthquake symbology system.%地震灾害符号的研究已经成为地震应急工作的一项重要内容,本文借助于符号学及传播学的方法论,在分析地震灾害符号的符号学内涵、使用人群和传播内容的基础上,探讨了地震灾害符号体系的特点及构建原则.地震本身的特殊性和破坏性决定了地震灾害符号体系的特殊性和时间性,本文在遵循实用性、主次性及概括性三个原则的前提下,提出了一套地震灾害符号体系构建的理论框架,可为地震灾害符号体系的构建和深入研究提供参考.
Institute of Scientific and Technical Information of China (English)
李昌勇; 张临杰; 赵建明; 贾锁堂
2012-01-01
Rydberg atoms has been one of the hot current research subjects in the field of physics becasue of its large volume, long life, easy polarization and energy levels easily controlled by external electric field. In this paper, the Stark energies and electric dipole moments of 15/93/2 and 16/93/2 of atomic cesium are measured experimentally. The empirical analytic equations of dipole moments and Stark energies for these two states are presented. We also numerically solve the Schr/Sdinger equation and obtain Stark energies, dipole moments, and electron probability density distributions. The probability density distribution accords with the calculated dipole moments. The Stark energies and dipole moments are consistent with our experimental results. To the best of our knowledge, the measurement and calculation methods for dipole moments presented in this paper are reported for the first time.%里德堡原子由于具有体积大、寿命长、易极化及在外电场中能级易于操控等特点，已经成为了目前物理学领域研究的热点之一．本文在磁光阱中实验测量了铯原子15P3／2和16P3／2态的Stark光谱，根据光谱给出了15P 3／2和16P3／2｜m｜=1／2Stark态在0-1400V／cm场强范围适用的Stark能量和偶极矩的经验性解析表达式；用数值方法求解薛定谔方程获得了这些态的Stark能量、偶极矩和电子几率密度分布．电子几率密度分布定性说明了计算的偶极矩矢量的方向是正确的．计算的Stark能量、偶极矩与实验结果相一致．
Institute of Scientific and Technical Information of China (English)
王宗志; 张玲玲; 王银堂; 金菊良; 程亮
2012-01-01
The initial basin water rights assignment is not only the important premise that realize the reasonable water rights circulation and play a fundamental role in market allocation water resources, it is also the important content under the China socialist market economy condition to realize the basin water resources integrated dispatch and to alleviate water resources supply and demand contradiction. To provide technical support for promoting the construction process of China 's water rights system and implementing the most stringent water resources management system, based on existing research results of two-dimensional water rights concept and connotation, and considering the research progress of the initial water rights allocation at home and abroad, the theoretical framework is put forward including the initial two dimensional water rights allocation (simplified initial allocation) , the basin water resources optimal regulation based on the initial two-dimensional water rights (simplified as optimal regulation) and three-part real-time control, and further elaborated on the modeling process and support technology and its work relation of the above three elements.%为推动中国水权制度建设进程与落实最严格水资源管理制度提供技术支撑,基于二维水权概念与内涵等现有研究成果,结合对国内外初始水权分配相关研究进展与需求实践的系统梳理,从供水管理视角提出了包括“初始分配”、“优化调控”和“实时调控”3项内容在内的基于初始二维水权的流域水资源调控理论框架,详细阐述了各组成部分的实现途径、支撑技术、建模步骤及其之间的工作关系.
Institute of Scientific and Technical Information of China (English)
王双力; 梁军; 陶松涛; 崔执凤
2015-01-01
On the basis of the closed expression of the Franck-Condon overlap integrals between arbitrary multi-dimensional harmonic oscillators and considering influence of the Duschinsky effects, a more general algebraic expression for the calculation of the three -dimensional three -mode Franck -Condon factors was derived straightforwardly.This algebraic expression was applied to study the photoelectron spectra of H2 CO.Franck-Condon analyses and spectral simulations were carried out on the H2 CO+( B珘2 A1 )←H2 CO( X珘1 A1 ) photoionization processes.The spectral simulations of vibrational structures based on the computed Franck-Condon factors are in excellent agreement with the observed spectra.%本文凭借多振动模混合下任意维Franck-Condon 重叠积分封闭表示，推导出三维三振动模Franck-Condon重叠积分的解析表示式；基于厄米多项式的级数形式，得到计算三维三振动模Franck-Condon 因子的一般代数表示式。另外，应用Franck-Condon因子的代数表示，研究甲醛光电子能谱的强度分布及振动结构。对于H2 CO＋（Β珟2 A1）←H2 CO（ X珘1 A1）离子化过程，基于ab initio力常数及几何参数，计算Franck－Condon因子，得到光电子能谱的谱线相对强度。结果表明理论模拟得到的光电子能谱与实验上观测到的能谱达到较好的一致；基于光谱模拟使人们能够对实验谱给予合理解释以及对谱峰进行正确归属。
Institute of Scientific and Technical Information of China (English)
黄时中; 张法保; 王大理; 李伟艳; 胡健
2006-01-01
Based on the tensor expression of the fine structure Hamiltonian and the non-relativistic energy structure theory for helium, and by virtue of irreducible tensor theory, an analytical method for calculating the fine structure parameter for spin-other-orbit interaction in helium-like atoms is established. All the angular integrations and spin summations involved in the problem have been carried out explicitly, the parameter is expressed finally as a sum of some radial integrations. Approximate evaluation for these radial integrations in the (1s2p)3P state of helium is outlined, in which the hydrogen-like radial functions are employed. It is found that in the fine structure of helium, the spin-other-orbit interaction and the pure spin-orbit interaction act in the opposite directions, and it is the former that plays the most important role, which determines the splitting order of the fine structure.%以多电子原子精细结构哈密顿的球张量形式和氦原子非相对论性能级结构理论为基础,借助不可约张量理论, 建立了计算氦原子自旋-其它轨道相互作用精细结构参数的一种解析理论形式.完成了所有的角向积分和自旋求和计算,自旋-其它轨道相互作用精细结构参数最终用若干个径向积分来表示.以氦原子(1s2p)3P态为例,借用类氢形式的径向函数对这些径向积分进行了近似计算.计算结果表明:在氦原子的精细结构中,自旋-其它轨道相互作用与纯自旋-轨道相互作用的作用效果相反;在总自旋-轨道相互作用精细结构参数中,自旋-其它轨道相互作用起决定性作用,它决定着精细结构分裂的顺序.
Institute of Scientific and Technical Information of China (English)
刘庭磊; 王韶; 张知; 朱姜峰
2015-01-01
In order to calculate the theoretical line loss of low-voltage distribution transformer district and improve the line loss management level by using automatic meter reading system, a Newton-Raphson method to calculate the theoretical line loss of low-voltage distribution transformer district by adopting the load electrical energy is proposed. On the basis of the equivalent resistance method and the electrical energy acquired from the watt-hour meters of customers, the mathematical model of regarding theoretical line loss of transformer district as a variable is created. The model introduces relationship between load shape coefficients and the average load current, and the line loss modified coefficient of unbalanced three-phase load. The procedure of the Newton-Raphson method to solve the model is presented. Case analyses show that the proposed method can not only calculate the theoretical line loss of low-voltage distribution transformer district, but also provide the information to identify unknown line loss.%为计算低压配电台区理论线损和利用远程自动抄表系统提高管理线损水平,提出一种采用负荷电量计算低压配电台区理论线损的牛拉法.该方法基于等值电阻法和用户电能表实抄电量,通过引入线路负荷曲线形状系数与平均负荷电流的关系和三相负荷不平衡线损修正系数建立以台区理论线损为变量的数学模型.给出了运用牛拉法求解该模型的实现过程.算例分析表明,提出的方法不仅能够计算低压配电台区的理论线损,而且能够为识别不明线损提供信息.
Amato, Maria E.; Bandoli, Giuliano; Djedaïni, Florence; Dolmella, Alessandro; Grassi, Antonio; Pappalardo, Giuseppe C.
1990-05-01
The crystal and molecular structures of the cognition activators 1-(4-methoxybenzoyl)-5-oxo-2-pyrrolidinepropanoic acid (CI-933) ( 1) and 4-hydroxymethyl-1-benzyl-pyrrolidin-2-one (WEB-1868) ( 2) have been determined by X-ray analysis. The conformations of the isolated molecules 1 and 2 have been deduced from AM1-type theoretical calculations. Whilst in 1 there are no hydrogen bonds, in 2 stabilization of the crystal occurs through effective inter- and intramolecular ? bonds. The five-membered ring in both 1 and 2 adopts an envelope conformation in the solid with C(3) at the flap displaced from the C(1), C(2), C(4), N(5) mean plane. Bond distances and angles are normal and comparable with previously known similar structures. In the crystal, the torsion angles C(1)-N(5)-C(6)-C(7) and N(5)-C(6)-C(7)-C(8) in 1 are 43.1° and 44.8°, respectively; the same torsion angles in 2 are -101° and 42°, respectively. Results of theoretical calculations correlate well with the conformation of 1 in the solid, whilst in the case of 2 these indicate that the conformation in the crystal should not be retained by the isolated molecule. The complete analysis of the very high field (600 MHz) 1H NMR spectra of both compounds in CDCl 3, gives results well in line with the above established conformational features.
Institute of Scientific and Technical Information of China (English)
吴鸿亮; 门锟; 董楠; 廖兵兵; 郑全朝
2016-01-01
In order to strengthen the meticulous management of line loss and improve the economic benefits of electric power company, this paper establishes the model of electric energy loss calculation model of power grid component in HVDC system and diagnosis analysis and loss reduction potential analysis of line loss, develops theoretical calculation and diagnosis analysis system of line loss based on J2EE framework. With the EMS system, SCADA system, production management system, measurement automation system, marketing management system, distribution network automation system, and the data centralized management system, through the open design, it not only realizes the automatic extraction of line loss data and efficient synthesis, but also achieves the line loss theoretical calculation online, energy loss diagnosis analysis and loss reduction potential analysis function. The proposed system has high security and portability, and can provide a scientific decision-making tool for theoretical calculation of line loss and meticulous management, economic operation, power grid planning and energy saving reconstruction, so it has broad application prospect.%为加强电网线损精细化管理水平和提高电力企业经济效益，建立了高压直流输电系统电网元件电能损耗计算、线损诊断分析及降损潜力分析模型，研发了基于 J2EE 架构的线损理论计算与诊断分析系统。该系统通过与EMS系统、SCADA系统、生产管理系统、计量自动化系统、营销管理系统、配网自动化系统以及营配数据集中管理系统的开放性接口设计，不仅实现了线损数据的自动抽取和高效合成，还实现了线损理论在线计算和线损诊断分析及降损潜力分析功能。该系统安全性高，可移植性强，为电网线损理论计算及精细化管理、电网经济运行、电网规划与节能改造提供科学决策工具，具有广阔的应用前景。
Theoretical, Methodological, and Empirical Approaches to Cost Savings: A Compendium
Energy Technology Data Exchange (ETDEWEB)
M Weimar
1998-12-10
This publication summarizes and contains the original documentation for understanding why the U.S. Department of Energy's (DOE's) privatization approach provides cost savings and the different approaches that could be used in calculating cost savings for the Tank Waste Remediation System (TWRS) Phase I contract. The initial section summarizes the approaches in the different papers. The appendices are the individual source papers which have been reviewed by individuals outside of the Pacific Northwest National Laboratory and the TWRS Program. Appendix A provides a theoretical basis for and estimate of the level of savings that can be" obtained from a fixed-priced contract with performance risk maintained by the contractor. Appendix B provides the methodology for determining cost savings when comparing a fixed-priced contractor with a Management and Operations (M&O) contractor (cost-plus contractor). Appendix C summarizes the economic model used to calculate cost savings and provides hypothetical output from preliminary calculations. Appendix D provides the summary of the approach for the DOE-Richland Operations Office (RL) estimate of the M&O contractor to perform the same work as BNFL Inc. Appendix E contains information on cost growth and per metric ton of glass costs for high-level waste at two other DOE sites, West Valley and Savannah River. Appendix F addresses a risk allocation analysis of the BNFL proposal that indicates,that the current approach is still better than the alternative.
Applications of theoretical methods in atmospheric science
DEFF Research Database (Denmark)
Johnson, Matthew Stanley; Goodsite, Michael E.
2008-01-01
Theoretical chemistry involves explaining chemical phenomenon using natural laws. The primary tool of theoretical chemistry is quantum chemistry, and the field may be divided into electronic structure calculations, reaction dynamics and statistical mechanics. These three all play a role in addres...
Beauty baryon decays: a theoretical overview
Wang, Yu-Ming
2014-11-01
I overview the theoretical status and recent progress on the calculations of beauty baryon decays focusing on the QCD aspects of the exclusive semi-leptonic Λb → plμ decay at large recoil and theoretical challenges of radiative and electro-weak penguin decays Λb → Λγ,Λl+l-.
McCarty, George
1982-01-01
How THIS BOOK DIFFERS This book is about the calculus. What distinguishes it, however, from other books is that it uses the pocket calculator to illustrate the theory. A computation that requires hours of labor when done by hand with tables is quite inappropriate as an example or exercise in a beginning calculus course. But that same computation can become a delicate illustration of the theory when the student does it in seconds on his calculator. t Furthermore, the student's own personal involvement and easy accomplishment give hi~ reassurance and en couragement. The machine is like a microscope, and its magnification is a hundred millionfold. We shall be interested in limits, and no stage of numerical approximation proves anything about the limit. However, the derivative of fex) = 67.SgX, for instance, acquires real meaning when a student first appreciates its values as numbers, as limits of 10 100 1000 t A quick example is 1.1 , 1.01 , 1.001 , •••• Another example is t = 0.1, 0.01, in the functio...
Petsalakis, I D; Georgiadou, D G; Vasilopoulou, M; Pistolis, G; Dimotikali, D; Argitis, P; Theodorakopoulos, G
2010-05-06
A theoretical investigation on the electronic structure of 4-dimethylamino-4'-nitrostilbene (DANS), 4-(dicyanomethylene)-2-methyl-6-p-(dimethylamino) styryl-4H-pyran (DCM), and their protonated forms is presented in an effort to rationalize recent experimental results on the tuning of the emitted color of organic light-emitting diodes through photochemically induced protonation. Density functional theory (DFT) and time-dependent density functional theory (TDDFT) calculations have been carried out on the neutral and protonated forms of DANS and DCM, employing both the B3LYP and the CAM-B3LYP functionals. It was found that the CAM-B3LYP functional leads to better agreement than the B3LYP of the calculated with the experimental absorption lambda(max) for DANS, whereas B3LYP is more appropriate than CAM-B3LYP for DCM. The results of the calculations aid in a rationalization of the observed differences of the spectra of DANS and DCM upon protonation, and in particular those differences that make DANS a more attractive system for absorbance and emission tuning.
Linewidth calculations and simulations
Strandberg, Ingrid
2016-01-01
We are currently developing a new technique to further enhance the sensitivity of collinear laser spectroscopy in order to study the most exotic nuclides available at radioactive ion beam facilities, such as ISOLDE at CERN. The overall goal is to evaluate the feasibility of the new method. This report will focus on the determination of the expected linewidth (hence resolution) of this approach. Different effects which could lead to a broadening of the linewidth, e.g. the ions' energy spread and their trajectories inside the trap, are studied with theoretical calculations as well as simulations.
Calculations in furnace technology
Davies, Clive; Hopkins, DW; Owen, WS
2013-01-01
Calculations in Furnace Technology presents the theoretical and practical aspects of furnace technology. This book provides information pertinent to the development, application, and efficiency of furnace technology. Organized into eight chapters, this book begins with an overview of the exothermic reactions that occur when carbon, hydrogen, and sulfur are burned to release the energy available in the fuel. This text then evaluates the efficiencies to measure the quantity of fuel used, of flue gases leaving the plant, of air entering, and the heat lost to the surroundings. Other chapters consi
Energy Technology Data Exchange (ETDEWEB)
Hubbard, W. B. [Lunar and Planetary Laboratory, The University of Arizona, Tucson, AZ 85721 (United States); Militzer, B. [Department of Earth and Planetary Science, Department of Astronomy, University of California, Berkeley, CA 94720 (United States)
2016-03-20
In anticipation of new observational results for Jupiter's axial moment of inertia and gravitational zonal harmonic coefficients from the forthcoming Juno orbiter, we present a number of preliminary Jupiter interior models. We combine results from ab initio computer simulations of hydrogen–helium mixtures, including immiscibility calculations, with a new nonperturbative calculation of Jupiter's zonal harmonic coefficients, to derive a self-consistent model for the planet's external gravity and moment of inertia. We assume helium rain modified the interior temperature and composition profiles. Our calculation predicts zonal harmonic values to which measurements can be compared. Although some models fit the observed (pre-Juno) second- and fourth-order zonal harmonics to within their error bars, our preferred reference model predicts a fourth-order zonal harmonic whose absolute value lies above the pre-Juno error bars. This model has a dense core of about 12 Earth masses and a hydrogen–helium-rich envelope with approximately three times solar metallicity.
Theoretical Calculations of H(2) CARS Spectra for Propellant Flames
1983-12-01
FLAMES JOANNE FENDELL L. E. HARRIS KENNETH ARON DECEMBER 1983 U.S. ARMY ARMAMENT RESEARCH AND.DEVELOPMENT CENTER URGE CAUBER WEAPON SYSTEMS...TYPE OF REPORT & PERIOD COVERED 6. PERFORMING ORG. REPORT NUMBER 7. AUTHORfaJ Joanne Fendell L. E. Harris Kenneth Aron 8. CONTRACT OR GRANT...normalized population difference between the Personal communication between W. C. Erraler, Stevens Institute of Technology, Hoboken, NJ and J. Fendell
Study of nonplanarity of peptide bond using theoretical calculations.
Selvarengan, P; Kolandaivel, P
2005-08-01
The conformational dependence of nonplanarity of the peptide bond of formylglycinamide has been studied using ab initio and density functional theory methods. Hartree-Fock self-consistent field theory (HF), Møller-Plesset perturbation theory (MP2) of ab initio and B3LYP level of theory of dft method have been used employing 6-31++G** basis set. The MP2 method predicts better results than HF and B3LYP levels of theory for conformational stability dependence of nonplanarity. Systematic dependence of planarity deviation has been observed in MP2 theory. The chemical hardness values successfully predict the conformational region, but fail to obey maximum hardness principle. It is concluded that the most reliable dft method could not successfully predict the planarity of peptide bond in comparison with electron correlated method of ab initio method.
Gonzálvez, Alicia G; González Ureña, Ángel
2012-10-01
A laser spectroscopic technique is described that combines transmission and resonance-enhanced Raman inelastic scattering together with low laser power (view, a model for the Raman signal dependence on the sample thickness is also presented. Essentially, the model considers the sample to be homogeneous and describes the underlying physics using only three parameters: the Raman cross-section, the laser-radiation attenuation cross-section, and the Raman signal attenuation cross-section. The model was applied successfully to describe the sample-size dependence of the Raman signal in both β-carotene standards and carrot roots. The present technique could be useful for direct, fast, and nondestructive investigations in food quality control and analytical or physiological studies of animal and human tissues.
Institute of Scientific and Technical Information of China (English)
杨寿海; 陈义学; 王伟金; 靳忠敏; 陆道纲
2012-01-01
Based on the American H.B.Robinson-2 pressure vessel benchmark, the neutron spectrum in surveillance capsule and reaction rates for some species have been obtain by three-dimensional (3-D) discrete ordinates (Sn) method code (TORT). The results show that, the neutron spectrum in surveillance capsule makes good agreement with the benchmark, and the C/M of reaction rates for some species is 1.04±0.04 by TORT code. Then, the heat release rate distribution over reactor components has been calculated by TORT code and MCNP program for Ningde Nuclear Power Plant in Fujian China, and compared with each other. Finally, the application of TORT code in the calculation of the heating rate for PWR internals is presented and discussed.%以美国H.B.Robinson-2#机组反应堆压力容器(RPV)基准实验的参数为输入数据,采用三维离散纵标方法程序( TORT)计算压力辐照监督管处中子能谱及典型核素的活度值.计算得到的辐照监督管处中子能谱与基准实验结果趋势一致、吻合较好;典型核素活度的计算值与测量值之比(C/M)为1.04±0.04.用TORT对福建宁德核电站堆内构件释热率分布进行初步计算,并与蒙特卡罗方法(MCNP)的计算结果相比较,两种方法的结果表现出良好的一致性.最后对TORT程序应用于堆内释热率计算进行讨论.
Institute of Scientific and Technical Information of China (English)
张克武; 张宇英
2006-01-01
提出气体不平衡状态方程后,将其移植应用于气体平衡性质的研究,建立气体定压比热理论方程和两个定理;经用各种结构类型的538种气体纯质2398个实验数据检验,平均误差0.38%,显著优于文献中各式,尤其突出的是物理意义明晰,有一定的理论意义与实际应用价值,在基础理论研究中取得重要进展.%According to differential equation of Argon model the author has proposed a theoretical equation for the nonequilibrium state of gases (TENSG), that is extended here to the theoretical calculation of gaseous heat capacity. Thus an equation of the heat capacity of gases at constant pressure is derived. This equation applies to both polar and nonpolar gases, the average error from 2398 experimental values being 0. 38% based on 538 compounds. The method is far better than the other published methods. These results show that this work makes a great progress in basic research.
Theoretic Study of CⅡ Recombination Line
Institute of Scientific and Technical Information of China (English)
彭永伦; 王民盛; 韩小英; 李家明
2004-01-01
Using the R-matrix method, we carry out theoretical calculations for recombination line λ 8794 A(3d'-3p') of CⅡ, which is important to estimate the abundances of carbon in planetary nebulae. Our calculations are based on three sets of target orbital basis, through which we elucidate the electron correlation and static polarization effects in the dielectronic recombination processes.
A Preliminary Analysis of the Theoretical Parameters of Organizaational Learning.
1995-09-01
Management Equal Organizational Learning?," Quality Progress. 26: 39-43 (July 1993). Bateson , Gregory . Steps to an Ecology of Mind, New York...Learning about the context of learning itself. (Isaacs, 1994:46; Bateson , 1972) 2-7 The three levels of learning presented above provide a good...of learning called "triple-loop learning." ( Bateson , 1972:34). While double-loop learning as defined by Argyris encourages considering which
Michel Foucault on Education: A Preliminary Theoretical Overview
Deacon, Roger
2006-01-01
Michel Foucault's work is already well-known in the field of education. What is not yet well-known is that Foucault's oeuvre as a whole incorporates within itself and offers for wider consumption a number of key educational themes. For purposes of clarity, these themes can be reduced to three, dealing with what might be called the past, present,…
Equilibrium calculations of firework mixtures
Energy Technology Data Exchange (ETDEWEB)
Hobbs, M.L. [Sandia National Labs., Albuquerque, NM (United States); Tanaka, Katsumi; Iida, Mitsuaki; Matsunaga, Takehiro [National Inst. of Materials and Chemical Research, Tsukuba, Ibaraki (Japan)
1994-12-31
Thermochemical equilibrium calculations have been used to calculate detonation conditions for typical firework components including three report charges, two display charges, and black powder which is used as a fuse or launch charge. Calculations were performed with a modified version of the TIGER code which allows calculations with 900 gaseous and 600 condensed product species at high pressure. The detonation calculations presented in this paper are thought to be the first report on the theoretical study of firework detonation. Measured velocities for two report charges are available and compare favorably to predicted detonation velocities. However, the measured velocities may not be true detonation velocities. Fast deflagration rather than an ideal detonation occurs when reactants contain significant amounts of slow reacting constituents such as aluminum or titanium. Despite such uncertainties in reacting pyrotechnics, the detonation calculations do show the complex nature of condensed phase formation at elevated pressures and give an upper bound for measured velocities.
Preliminary Monthly Climatological Summaries
National Oceanic and Atmospheric Administration, Department of Commerce — Preliminary Local Climatological Data, recorded since 1970 on Weather Burean Form 1030 and then National Weather Service Form F-6. The preliminary climate data pages...
Directory of Open Access Journals (Sweden)
Sabria Aued-Pimentel
2008-01-01
Full Text Available The difference between the actual ECN 42 triacylglyceride content in vegetable oils, obtained by HPLC analysis, and the theoretical value calculated from the fatty acid composition was applied to detect the addition of seed oils with high contents of linoleic acid to olive oils commercialized in Brazil. The results indicate that samples analyzed were probably adulterated with low commercial value seed oils, rich in linoleic acid, like soybean, sunflower or corn.
Theoretical Provision of Tax Transformation
Directory of Open Access Journals (Sweden)
Feofanova Iryna V.
2016-05-01
Full Text Available The article is aimed at defining the questions, giving answers to which is necessary for scientific substantiation of the tax transformation in Ukraine. The article analyzes the structural-logical relationships of the theories, providing substantiation of tax systems and transformation of them. Various views on the level of both the tax burden and the distribution of the tax burden between big and small business have been systematized. The issues that require theoretical substantiation when choosing a model of tax system have been identified. It is determined that shares of both indirect and direct taxes and their rates can be substantiated by calculations on the basis of statistical data. The results of the presented research can be used to develop the algorithm for theoretical substantiation of tax transformation
Theoretical Advanced Study Institute: 2014
Energy Technology Data Exchange (ETDEWEB)
DeGrand, Thomas [Univ. of Colorado, Boulder, CO (United States)
2016-08-17
The Theoretical Advanced Study Institute (TASI) was held at the University of Colorado, Boulder, during June 2-27, 2014. The topic was "Journeys through the Precision Frontier: Amplitudes for Colliders." The organizers were Professors Lance Dixon (SLAC) and Frank Petriello (Northwestern and Argonne). There were fifty-one students. Nineteen lecturers gave sixty seventy-five minute lectures. A Proceedings was published. This TASI was unique for its large emphasis on methods for calculating amplitudes. This was embedded in a program describing recent theoretical and phenomenological developments in particle physics. Topics included introductions to the Standard Model, to QCD (both in a collider context and on the lattice), effective field theories, Higgs physics, neutrino interactions, an introduction to experimental techniques, and cosmology.
Institute of Scientific and Technical Information of China (English)
郑瑞杰; 王德永
2011-01-01
determination coefficient reached a significant level（P〈0.0001）,the unary quadratic regression equation of the product of the leaf length and width and leaf area had the best regression effect with the determination coefficient of 0.987 9 and the correction determination coefficient of 0.987 7;the binary linear regression relationship of the leaf biomass of individual plants with crown width and crown height reached a significant level（P〈0.0001）,the determination coefficient was 0.987 9 and the correction determination coefficient was 0.987 7.In production,the leaf biomass and leaf area indexes of individual plants could be calculated through the measurement on crown width and crown height.The method is simple to operate and has higher application value.
Directory of Open Access Journals (Sweden)
Yu Wang
2002-01-01
Full Text Available Abstract:We investigate a theoretical model of molecular metalwire constructed from linear polynuclear metal complexes. In particular we study the linear Crn metal complex and Cr molecular metalwire. The electron density distributions of the model nanowire and the linear Crn metal complexes, with n = 3, 5, and 7, are calculated by employing CRYSTAL98 package with topological analysis. The preliminary results indicate that the bonding types between any two neighboring Cr are all the same, namely the polarized open-shell interaction. The pattern of electron density distribution in metal complexes resembles that of the model Cr nanowire as the number of metal ions increases. The conductivity of the model Cr nanowire is also tested by performing the band structure calculation.
Qualitative methods in theoretical physics
Maslov, Dmitrii
2017-01-01
This book comprises a set of tools which allow researchers and students to arrive at a qualitatively correct answer without undertaking lengthy calculations. In general, Qualitative Methods in Theoretical Physics is about combining approximate mathematical methods with fundamental principles of physics: conservation laws and symmetries. Readers will learn how to simplify problems, how to estimate results, and how to apply symmetry arguments and conduct dimensional analysis. A comprehensive problem set is included. The book will appeal to a wide range of students and researchers.
Theoretical studies of combustion dynamics
Energy Technology Data Exchange (ETDEWEB)
Bowman, J.M. [Emory Univ., Atlanta, GA (United States)
1993-12-01
The basic objectives of this research program are to develop and apply theoretical techniques to fundamental dynamical processes of importance in gas-phase combustion. There are two major areas currently supported by this grant. One is reactive scattering of diatom-diatom systems, and the other is the dynamics of complex formation and decay based on L{sup 2} methods. In all of these studies, the authors focus on systems that are of interest experimentally, and for which potential energy surfaces based, at least in part, on ab initio calculations are available.
Institute of Scientific and Technical Information of China (English)
唐斌; 康盛伟; 王先良; 黎杰; 王培
2016-01-01
Objective To investigate the feasibility of the virtual source model in Monte Carlo dose calculation for clinical radiotherapy.Methods The Monte Carlo simulation was used to obtain the phase space files which recorded the physical properties of the particles emitted by a medical linear accelerator, and the information on the type, energy spectrum, and distribution of particles were extracted from these files and analyzed to establish the semi-empirical model of virtual two-photon source.The GMC dose calculation engine was used to obtain the 3 cm×3 cm, 5 cm×5 cm, 10 cm×10 cm, 20 cm×20 cm, and 30 cm×30 cm fields of radiotherapy and the results of Monte Carlo simulation of dose distribution in three-dimensional water phantom in 2 intensity-modulated radiotherapy ( IMRT) plans.These results were compared with the results of water phantom measurement or the results of Elekta Monaco planning system to verify the accuracy of Monte Carlo dose calculation based on a virtual source.Results As for the percentage depth-dose distribution curves of the central axis of the water phantom and the off-axis dose curves at different depths in the five fields for radiotherapy, the difference between the results of Monte Carlo simulation and the results of measurement was within 1%.As for the two IMRT plans, the three-dimensional passing rates of Monaco calculation results and Monte Carlo simulation results were 98.9%and 99.4%, respectively, for 3%/3 mm, and 95.1%and 95.4%, respectively, for 2%/2 mm.Conclusions Monte Carlo simulation based on the virtual source model can obtain accurate results of radiotherapy dose calculation.%目的：研究临床放疗蒙特卡洛剂量计算方法中虚拟源模型的可行性。方法通过蒙特卡洛方法模拟得到记录医用直线加速器机头出射粒子物理特性的相空间文件，分析提取相空间文件中粒子的种类、能谱及位置分布，建立半经验虚拟双光子源抽样模型。结合并
Institute of Scientific and Technical Information of China (English)
许新胜; 朱光来; 陆同兴; 崔执凤
2008-01-01
Based on the whole zero field splitting (zfs) inte raction of triplet molecule in the interaction Hamiltonian of stable radicals and excited triplet molecules complexes, the intensity of chemical induced dynamic electron polarization (CIDEP) originated from RTPM were theoretically calculated in detail. In the calculation, the second order perturbation theory and the motion equation are used. The result of calculation indicates that the polarization pattern is hyperfine related E+E/A or A+A/E pattern, in which the net emissive or net absorptive polarization results from the zero field splitting (zfs) and the E/A or A/E polarization results from hyperfine (hf) interactions of the radical. Furthermore, the zero field splitting interaction E(S2Tξ-S2Tη) makes the net polarization decrease and the hyperfine dependent polarization increase.%基于考虑含E(S2Tξ-S2Tη) 项的相互作用全哈密顿,利用密度矩阵运动方程,对自由基-三重态对机理的CIDEP强度进行了详细的理论计算.计算结果表明:四重态母体自由基-三重态机理(QP-RTPM)和二重态母体自由基-三重态机理(DP-RTPM)分别使稳定自由基形成发射+发射/吸收(E+E/A)和吸收+吸收/发射(A+A/E)型多重性极化,其中净E(A)极化由零场分裂相互作用产生,超精细相关E/A(A/E)极化由超精细相互作用产生.另外,零场分裂相互作用项E(S2Tξ-S2Tη) ,使稳定自由基的净极化减弱,超精细相关极化加强.
Preliminary considerations concerning actinide solubilities
Energy Technology Data Exchange (ETDEWEB)
Newton, T.W.; Bayhurst, B.P.; Daniels, W.R.; Erdal, B.R.; Ogard, A.E.
1980-01-01
Work at the Los Alamos Scientific Laboratory on the fundamental solution chemistry of the actinides has thus far been confined to preliminary considerations of the problems involved in developing an understanding of the precipitation and dissolution behavior of actinide compounds under environmental conditions. Attempts have been made to calculate solubility as a function of Eh and pH using the appropriate thermodynamic data; results have been presented in terms of contour maps showing lines of constant solubility as a function of Eh and pH. Possible methods of control of the redox potential of rock-groundwater systems by the use of Eh buffers (redox couples) is presented.
Friction and wear calculation methods
Kragelsky, I V; Kombalov, V S
1981-01-01
Friction and Wear: Calculation Methods provides an introduction to the main theories of a new branch of mechanics known as """"contact interaction of solids in relative motion."""" This branch is closely bound up with other sciences, especially physics and chemistry. The book analyzes the nature of friction and wear, and some theoretical relationships that link the characteristics of the processes and the properties of the contacting bodies essential for practical application of the theories in calculating friction forces and wear values. The effect of the environment on friction and wear is a
Blatt, John M
2010-01-01
A classic work by two leading physicists and scientific educators endures as an uncommonly clear and cogent investigation and correlation of key aspects of theoretical nuclear physics. It is probably the most widely adopted book on the subject. The authors approach the subject as ""the theoretical concepts, methods, and considerations which have been devised in order to interpret the experimental material and to advance our ability to predict and control nuclear phenomena.""The present volume does not pretend to cover all aspects of theoretical nuclear physics. Its coverage is restricted to
Calculation of Temperature Rise in Calorimetry.
Canagaratna, Sebastian G.; Witt, Jerry
1988-01-01
Gives a simple but fuller account of the basis for accurately calculating temperature rise in calorimetry. Points out some misconceptions regarding these calculations. Describes two basic methods, the extrapolation to zero time and the equal area method. Discusses the theoretical basis of each and their underlying assumptions. (CW)
Experimental and theoretical study of the onset of the growth of an irregular metal electrodeposit
Energy Technology Data Exchange (ETDEWEB)
Gonzalez, Graciela [Laboratoire de Physique de la Matiere Condensee, CNRS-Ecole Polytechnique, F91128 Palaiseau Cedex (France); Laboratorio de Sistemas Complejos, Departamento de Computacion, Facultad de Ciencias, Exactas y Naturales, Universidad de Buenos Aires, 1428 Buenos Aires (Argentina); Rosso, Michel; Chazalviel, Jean-Noel [Laboratoire de Physique de la Matiere Condensee, CNRS-Ecole Polytechnique, F91128 Palaiseau Cedex (France); Chassaing, Elisabeth [IRDEP, EDF R and D, 6 Quai Watier, 78401 Chatou (France)
2007-11-20
Electrodeposition of a metal can produce aggregates with very irregular morphologies, in particular dendrites. In order to better understand these phenomena, we studied the preliminary stage of copper growth from copper sulfate by in situ optical experiments and impedance spectroscopy. Experiments were performed in a thin layer cell put in a vertical position, with cathode on top. Using a vertical cell instead of a horizontal one tends to stabilize the electrochemical system. The concentration measured by optical absorption is in agreement with theoretical prediction at the onset of polarization. Close to the limiting current density, oscillations were observed in the cell voltage. Impedance spectra could be fitted either using a simple equivalent circuit at low current density, or more complex calculations at high current density. (author)
DEFF Research Database (Denmark)
2002-01-01
The proceedings contains 8 papers from the Conference on Theoretical Computer Science. Topics discussed include: query by committee, linear separation and random walks; hardness results for neural network approximation problems; a geometric approach to leveraging weak learners; mind change...
Order-theoretical connectivity
Directory of Open Access Journals (Sweden)
T. A. Richmond
1990-01-01
Full Text Available Order-theoretically connected posets are introduced and applied to create the notion of T-connectivity in ordered topological spaces. As special cases T-connectivity contains classical connectivity, order-connectivity, and link-connectivity.
DEFF Research Database (Denmark)
2002-01-01
The proceedings contains 8 papers from the Conference on Theoretical Computer Science. Topics discussed include: query by committee, linear separation and random walks; hardness results for neural network approximation problems; a geometric approach to leveraging weak learners; mind change...
Consensus theoretic classification methods
Benediktsson, Jon A.; Swain, Philip H.
1992-01-01
Consensus theory is adopted as a means of classifying geographic data from multiple sources. The foundations and usefulness of different consensus theoretic methods are discussed in conjunction with pattern recognition. Weight selections for different data sources are considered and modeling of non-Gaussian data is investigated. The application of consensus theory in pattern recognition is tested on two data sets: 1) multisource remote sensing and geographic data and 2) very-high-dimensional remote sensing data. The results obtained using consensus theoretic methods are found to compare favorably with those obtained using well-known pattern recognition methods. The consensus theoretic methods can be applied in cases where the Gaussian maximum likelihood method cannot. Also, the consensus theoretic methods are computationally less demanding than the Gaussian maximum likelihood method and provide a means for weighting data sources differently.
Theoretical and computational chemistry.
Meuwly, Markus
2010-01-01
Computer-based and theoretical approaches to chemical problems can provide atomistic understanding of complex processes at the molecular level. Examples ranging from rates of ligand-binding reactions in proteins to structural and energetic investigations of diastereomers relevant to organo-catalysis are discussed in the following. They highlight the range of application of theoretical and computational methods to current questions in chemical research.
Theoretical physics and astrophysics
Ginzburg, VL
1979-01-01
The aim of this book is to present, on the one hand various topics in theoretical physics in depth - especially topics related to electrodynamics - and on the other hand to show how these topics find applications in various aspects of astrophysics. The first text on theoretical physics and astrophysical applications, it covers many recent advances including those in X-ray, &ggr;-ray and radio-astronomy, with comprehensive coverage of the literature
Theoretical Overview of Jet Photoproduction at HERA
Klasen, M.
1997-01-01
We review the theoretical framework of jet photoproduction at HERA discussing the conceptual ideas, phenomenological models, and higher order perturbative calculations. Numerically, we study the physically interesting distribution of transverse energy within the observed jet, the real and virtual photon structure, and the proton structure at large x.
Institute of Scientific and Technical Information of China (English)
夏云峰; 闻云呈; 张世钊; 徐华
2012-01-01
With the development of the 12. 5 m deep-water channel of the Yangtze River estuary, the deep water channel extending up to Nanjing is in urgent need. The start-up year of the existing datum of Nanjing downstream is 1970. In the study, the navigation datum upstream of Jiangyin has been adopted, and the theoretical datum downstream of Jiangyin has been used. With the human activities such as river channel regulations and bridge construction and the natural factors such as sea level rise, the tidal wave from Nanjing downstream has been transformed along distance, the existing datum needs to be recalculated and rechecked. In this paper, tide data of different stations along distance has been collected, interpolated, extended and completed by one dimensional mathematical model. Based on these tide level data, we calculated the datum plane of Nanjing downstream by use of integrated cumulative curve method, and compared the difference between existing datum planes and our calculation datum planes. It is shown that the existing datum planes can ensure ship navigation safety, and that the charts, topographic maps and relevant research results based on the existing datum are reliable and applicable.%由于沿江河道治理、航道整治、桥梁建设等人类活动以及海平面上升等因素的影响,南京以下沿程潮波发生变形,现行的基面需要重新计算与复核.通过收集沿程各站潮位资料,并利用一维数学模型对资料进行插补延伸；根据所得的沿程各站潮位资料,采用综合历时曲线法等手段对南京以下基面进行计算,比较现行基面与本次计算基面的差异.研究表明,南京以下现行的基面是可行的,且对船舶的航行是偏安全的,利用现行基面所测量的海图、地形图及研究成果可信有效.
Zarycz, Natalia; Botek, Edith; Champagne, Benoît; Sciannaméa, Valérie; Jérôme, Christine; Detrembleur, Christophe
2008-08-28
Density functional theory (DFT) calculations have been performed to address the structure of nitroxide intermediates in controlled radical polymerization. In a preliminary step, the reliability of different theoretical methods has been substantiated by comparing calculated hyperfine coupling constants (HFCCs) to experimental data for a set of linear and cyclic alkylnitroxyl radicals. Considering this tested approach, the nature of different nitroxides has been predicted or confirmed for (a) the reaction of C-phenyl- N- tert-butylnitrone and AIBN, (b) N- tert-butyl-alpha-isopropylnitrone and benzoyl peroxide, (c) tert-butyl methacrylate polymerization in the presence of sodium nitrite as mediator, and (d) for the reaction of a nitroso compound with AIBN. Values of HFCC experimentally determined have been confirmed by DFT calculations.
THEORETICAL MODEL OF VIBRATING OBJECT TRANSMITTING NOISE TOWARDS EXTERNAL SOUND
Institute of Scientific and Technical Information of China (English)
姚志远
2002-01-01
On the basic theory of modal method, the coupling relation between the vibration of objects and external sound was analyzed, the theoretical model solving the vibration and noise was provided, the corresponding calculation formula was given. The calculating results show out that this calculation formula is correct.
Directory of Open Access Journals (Sweden)
Dagiuklas Tasos
2011-01-01
Full Text Available This paper presents a Wireless Information-Theoretic Security (WITS scheme, which has been recently introduced as a robust physical layer-based security solution, especially for infrastructureless networks. An autonomic network of moving users was implemented via 802.11n nodes of an ad hoc network for an outdoor topology with obstacles. Obstructed-Line-of-Sight (OLOS and Non-Line-of-Sight (NLOS propagation scenarios were examined. Low-speed user movement was considered, so that Doppler spread could be discarded. A transmitter and a legitimate receiver exchanged information in the presence of a moving eavesdropper. Average Signal-to-Noise Ratio (SNR values were acquired for both the main and the wiretap channel, and the Probability of Nonzero Secrecy Capacity was calculated based on theoretical formula. Experimental results validate theoretical findings stressing the importance of user location and mobility schemes on the robustness of Wireless Information-Theoretic Security and call for further theoretical analysis.
Reflections on theoretical pragmatics
Institute of Scientific and Technical Information of China (English)
黄衍
2001-01-01
This paper provides a critical survey of theoretical pragmatics in contemporary linguistics. Among the topics that are addressed in the essay include the Anglo-American, and European Continental schools of thought;neo-Gricean pragmatic, and Relevance theories, the pragmatics-semantics interface; and the pragmatics-syntax interface.
Institute of Scientific and Technical Information of China (English)
李乐; 李志刚; 李鑫; 史仲平
2013-01-01
在丁醇发酵产溶剂阶段,乙酸和丁酸的生成途径、消耗途径同时存在,各自形成一个闭环路径.本研究利用图论对丁醇发酵中丁醇丙酮质量比进行了理论计算,并对以木薯和玉米为原料的丁醇发酵进行了模拟计算,结果表明:丁酸闭环路径(L2环)的代谢强度是影响丁醇丙酮质量比的主要因素,并且L2环的代谢强度越弱,丁醇丙酮质量比越高;与玉米原料丁醇发酵相比,木薯原料发酵的m(丁醇)/m(丙酮)提高了16.7％.实验结果证实了以上计算结果:在传统发酵、油醇萃取发酵和生物柴油萃取发酵中,以木薯(适时添加酵母浸粉)为原料的发酵批次与以玉米为原料的发酵批次相比,由于其丁酸闭环路径代谢强度较弱,相应发酵方式下丁醇丙酮质量比分别提高了12.9％、61.4％和6.7％,而且两种原料相应发酵方式的丁醇总产量和生产效率基本持平.另外,高丁醇丙酮质量比的木薯发酵所得改良型生物柴油中丁醇浓度与玉米发酵的相比提高了16％,性能得到进一步提高.%ABE fermentation is characterized with acetate butyrate formation and re-assimilation in multiple closed reaction loops during solventogenesis phase.In this study,we estimated butanol acetone mass ratio using graph theory for bio-butanol production utilizing cassava and corn based media.Theoretical calculations revealed that the metabolic strength of butyrate loop (L2) dominantly influenced butanol acetone mass ratio and lower metabolic strength in butyrate loop led to a higher butanol acetone mass ratio,and the ratio could be increased by 16.7％ when using cassava based medium.Experimental results confirmed the theoretical estimations:weakened metabolic strength in butyrate loop using cassava based medium led to higher butanol acetone mass ratios in traditional fermentation and extractive fermentations with oleyl alcohol and biodiesel as the extractants,and butanol acetone mass ratios
Energy Technology Data Exchange (ETDEWEB)
Cohen, Andrew [Boston Univ., MA (United States); Schmaltz, Martin [Boston Univ., MA (United States); Katz, Emmanuel [Boston Univ., MA (United States); Rebbi, Claudio [Boston Univ., MA (United States); Glashow, Sheldon [Boston Univ., MA (United States); Brower, Richard [Boston Univ., MA (United States); Pi, So-Young [Boston Univ., MA (United States)
2016-09-30
This award supported a broadly based research effort in theoretical particle physics, including research aimed at uncovering the laws of nature at short (subatomic) and long (cosmological) distances. These theoretical developments apply to experiments in laboratories such as CERN, the facility that operates the Large Hadron Collider outside Geneva, as well as to cosmological investigations done using telescopes and satellites. The results reported here apply to physics beyond the so-called Standard Model of particle physics; physics of high energy collisions such as those observed at the Large Hadron Collider; theoretical and mathematical tools and frameworks for describing the laws of nature at short distances; cosmology and astrophysics; and analytic and computational methods to solve theories of short distance physics. Some specific research accomplishments include + Theories of the electroweak interactions, the forces that give rise to many forms of radioactive decay; + Physics of the recently discovered Higgs boson. + Models and phenomenology of dark matter, the mysterious component of the universe, that has so far been detected only by its gravitational effects. + High energy particles in astrophysics and cosmology. + Algorithmic research and Computational methods for physics of and beyond the Standard Model. + Theory and applications of relativity and its possible limitations. + Topological effects in field theory and cosmology. + Conformally invariant systems and AdS/CFT. This award also supported significant training of students and postdoctoral fellows to lead the research effort in particle theory for the coming decades. These students and fellows worked closely with other members of the group as well as theoretical and experimental colleagues throughout the physics community. Many of the research projects funded by this grant arose in response to recently obtained experimental results in the areas of particle physics and cosmology. We describe a few of
The TRI preliminary dataset includes the most current TRI data available and reflects toxic chemical releases and pollution prevention activities that occurred at TRI facilities during the 2016 calendar year.
Friedrich, Harald
2017-01-01
This expanded and updated well-established textbook contains an advanced presentation of quantum mechanics adapted to the requirements of modern atomic physics. It includes topics of current interest such as semiclassical theory, chaos, atom optics and Bose-Einstein condensation in atomic gases. In order to facilitate the consolidation of the material covered, various problems are included, together with complete solutions. The emphasis on theory enables the reader to appreciate the fundamental assumptions underlying standard theoretical constructs and to embark on independent research projects. The fourth edition of Theoretical Atomic Physics contains an updated treatment of the sections involving scattering theory and near-threshold phenomena manifest in the behaviour of cold atoms (and molecules). Special attention is given to the quantization of weakly bound states just below the continuum threshold and to low-energy scattering and quantum reflection just above. Particular emphasis is laid on the fundamen...
Compendium of theoretical physics
Wachter, Armin
2006-01-01
Mechanics, Electrodynamics, Quantum Mechanics, and Statistical Mechanics and Thermodynamics comprise the canonical undergraduate curriculum of theoretical physics. In Compendium of Theoretical Physics, Armin Wachter and Henning Hoeber offer a concise, rigorous and structured overview that will be invaluable for students preparing for their qualifying examinations, readers needing a supplement to standard textbooks, and research or industrial physicists seeking a bridge between extensive textbooks and formula books. The authors take an axiomatic-deductive approach to each topic, starting the discussion of each theory with its fundamental equations. By subsequently deriving the various physical relationships and laws in logical rather than chronological order, and by using a consistent presentation and notation throughout, they emphasize the connections between the individual theories. The reader’s understanding is then reinforced with exercises, solutions and topic summaries. Unique Features: Every topic is ...
Robustness - theoretical framework
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Rizzuto, Enrico; Faber, Michael H.
2010-01-01
More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new struct...... of this fact sheet is to describe a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines....
Electrochemical kinetics theoretical aspects
Vetter, Klaus J
1967-01-01
Electrochemical Kinetics: Theoretical Aspects focuses on the processes, methodologies, reactions, and transformations in electrochemical kinetics. The book first offers information on electrochemical thermodynamics and the theory of overvoltage. Topics include equilibrium potentials, concepts and definitions, electrical double layer and electrocapillarity, and charge-transfer, diffusion, and reaction overvoltage. Crystallization overvoltage, total overvoltage, and resistance polarization are also discussed. The text then examines the methods of determining electrochemical reaction mechanisms
Silicene: Recent theoretical advances
Lew Yan Voon, L. C.
2016-04-14
Silicene is a two-dimensional allotrope of silicon with a puckered hexagonal structure closely related to the structure of graphene and that has been predicted to be stable. To date, it has been successfully grown in solution (functionalized) and on substrates. The goal of this review is to provide a summary of recent theoretical advances in the properties of both free-standing silicene as well as in interaction with molecules and substrates, and of proposed device applications.
MARKETING MIX THEORETICAL ASPECTS
Margarita Išoraitė
2016-01-01
Aim of article is to analyze marketing mix theoretical aspects. The article discusses that marketing mix is one of the main objectives of the marketing mix elements for setting objectives and marketing budget measures. The importance of each element depends not only on the company and its activities, but also on the competition and time. All marketing elements are interrelated and should be seen in the whole of their actions. Some items may have greater importance than others; it depends main...
Robustness - theoretical framework
DEFF Research Database (Denmark)
Sørensen, John Dalsgaard; Rizzuto, Enrico; Faber, Michael H.
2010-01-01
More frequent use of advanced types of structures with limited redundancy and serious consequences in case of failure combined with increased requirements to efficiency in design and execution followed by increased risk of human errors has made the need of requirements to robustness of new struct...... of this fact sheet is to describe a theoretical and risk based framework to form the basis for quantification of robustness and for pre-normative guidelines....
Theoretical numerical analysis
Wendroff, Burton
1966-01-01
Theoretical Numerical Analysis focuses on the presentation of numerical analysis as a legitimate branch of mathematics. The publication first elaborates on interpolation and quadrature and approximation. Discussions focus on the degree of approximation by polynomials, Chebyshev approximation, orthogonal polynomials and Gaussian quadrature, approximation by interpolation, nonanalytic interpolation and associated quadrature, and Hermite interpolation. The text then ponders on ordinary differential equations and solutions of equations. Topics include iterative methods for nonlinear systems, matri
Theoretical Developments in SUSY
Shifman, M.
2009-01-01
I am proud that I was personally acquainted with Julius Wess. We first met in 1999 when I was working on the Yuri Golfand Memorial Volume (The Many Faces of the Superworld, World Scientific, Singapore, 2000). I invited him to contribute, and he accepted this invitation with enthusiasm. After that, we met many times, mostly at various conferences in Germany and elsewhere. I was lucky to discuss with Julius questions of theoretical physics, and hear his recollections on how supersymmetry was born. In physics Julius was a visionary, who paved the way to generations of followers. In everyday life he was a kind and modest person, always ready to extend a helping hand to people who were in need of his help. I remember him telling me how concerned he was about the fate of theoretical physicists in Eastern Europe after the demise of communism. His ties with Israeli physicists bore a special character. I am honored by the opportunity to contribute an article to the Julius Wess Memorial Volume. I will review theoretical developments of the recent years in non-perturbative supersymmetry.
Theoretical developments in SUSY
Energy Technology Data Exchange (ETDEWEB)
Shifman, M. [University of Minnesota, William I. Fine Theoretical Physics Institute, Minneapolis, MN (United States)
2009-01-15
I am proud that I was personally acquainted with Julius Wess. We first met in 1999 when I was working on the Yuri Golfand Memorial Volume (The Many Faces of the Superworld, World Scientific, Singapore, 2000). I invited him to contribute, and he accepted this invitation with enthusiasm. After that, we met many times, mostly at various conferences in Germany and elsewhere. I was lucky to discuss with Julius questions of theoretical physics, and hear his recollections on how supersymmetry was born. In physics Julius was a visionary, who paved the way to generations of followers. In everyday life he was a kind and modest person, always ready to extend a helping hand to people who were in need of his help. I remember him telling me how concerned he was about the fate of theoretical physicists in Eastern Europe after the demise of communism. His ties with Israeli physicists bore a special character. I am honored by the opportunity to contribute an article to the Julius Wess Memorial Volume. I review theoretical developments of the recent years in non-perturbative supersymmetry. (orig.)
Morning and Night People in the Family: A Preliminary Statement
Adams, Bert N.; And Others
1978-01-01
This paper is a preliminary statement about morning and night people. The authors collected and analyzed married student responses to open-ended questions concerning "morningness" and "nightness" as factors influencing individual, marital, and family adjustment. This issue has both theoretical and practical significance for marriage and the…
National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Calculator will calculate the total magnetic field, including components (declination, inclination, horizontal intensity, northerly intensity,...
Information theoretic approach for accounting classification
Ribeiro, E M S
2014-01-01
In this paper we consider an information theoretic approach for the accounting classification process. We propose a matrix formalism and an algorithm for calculations of information theoretic measures associated to accounting classification. The formalism may be useful for further generalizations, and computer based implementation. Information theoretic measures, mutual information and symmetric uncertainty, were evaluated for daily transactions recorded in the chart of accounts of a small company during two years. Variation in the information measures due the aggregation of data in the process of accounting classification is observed. In particular, the symmetric uncertainty seems to be a useful parameter for comparing companies over time or in different sectors; or different accounting choices and standards.
A queer-theoretical approach to community health psychology.
Easpaig, Bróna R Nic Giolla; Fryer, David M; Linn, Seònaid E; Humphrey, Rhianna H
2014-01-01
Queer-theoretical resources offer ways of productively rethinking how central concepts such as 'person-context', 'identity' and 'difference' may be understood for community health psychologists. This would require going beyond consideration of the problems with which queer theory is popularly associated to cautiously engage with the aspects of this work relevant to the promotion of collective practice and engaging with processes of marginalisation. In this article, we will draw upon and illustrate the queer-theoretical concepts of 'performativity' and 'cultural intelligibility' before moving towards a preliminary mapping of what a queer-informed approach to community health psychology might involve.
From Game to Gamification: Preliminary Research of Gamification Marketing Theory
Directory of Open Access Journals (Sweden)
Dai-Yun Wu
2015-07-01
Full Text Available This article aims to provide a new understanding of the theoretical foundations of gamification and the related phenomena in the field of marketing communication. We started from redefining the concept of marketing gamification, and tried to point out the mechanisms of the phenomena by proposing theoretical basis from brand and consumer perspective separately. Finally, we tried to clarify some similar concepts, and put forward a marketing gamification model and a gamification concept map as the preliminary theoretical framework for further research in the future.
R-matrix calculation for photoionization
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
We have employed the R-matrix method to calculate differe ntial cross sections for photoionization of helium leaving helium ion in an exci ted state for incident photon energy between the N=2 and N=3 thresholds (69～73 eV) of He+ ion. Differential cross sections for photoionization in the N=2 level at emission angle 0° are provide. Our results are in good agreem ent with available experimental data and theoretical calculations.
Flow calculation of a bulb turbine
Energy Technology Data Exchange (ETDEWEB)
Goede, E.; Pestalozzi, J.
1987-01-01
In recent years remarkable progress has been made in the field of theoretical flow calculation. Studying the relevant literature one might receive the impression that most problems have been solved. But probing more deeply into details one becomes aware that by no means all questions are answered. The report tries to point out what may be expected of the quasi-three-dimensional flow calculation method employed and - much more important - what it must not be expected to accomplish. (orig.)
Linear Response Calculations of Spin Fluctuations
Savrasov, S. Y.
1998-09-01
A variational formulation of the time-dependent linear response based on the Sternheimer method is developed in order to make practical ab initio calculations of dynamical spin susceptibilities of solids. Using gradient density functional and a muffin-tin-orbital representation, the efficiency of the approach is demonstrated by applications to selected magnetic and strongly paramagnetic metals. The results are found to be consistent with experiment and are compared with previous theoretical calculations.
Efficient Theoretical Screening of Solid Sorbents for CO2 Capture Applications*
Energy Technology Data Exchange (ETDEWEB)
Duan, Yuhua; Luebke, David; Pennline, Henry
2012-03-31
By combining thermodynamic database mining with first principles density functional theory and phonon lattice dynamics calculations, a theoretical screening methodology to identify the most promising CO2 sorbent candidates from the vast array of possible solid materials has been proposed and validated. The ab initio thermodynamic technique has the advantage of allowing identification of thermodynamic properties of CO2 capture reactions without any experimental input beyond crystallographic structural information of the solid phases involved. For a given solid, the first step is to attempt to extract thermodynamic properties from thermodynamic databases and the available literatures. If the thermodynamic properties of the compound of interest are unknown, an ab initio thermodynamic approach is used to calculate them. These properties expressed conveniently as chemical potentials and heat of reactions, which obtained either from databases or from calculations, are further used for computing the thermodynamic reaction equilibrium properties of the CO2 absorption/desorption cycles. Only those solid materials for which lower capture energy costs are predicted at the desired process conditions are selected as CO2 sorbent candidates and are further considered for experimental validations. Solid sorbents containing alkali and alkaline earth metals have been reported in several previous studies to be good candidates for CO2 sorbent applications due to their high CO2 absorption capacity at moderate working temperatures. In addition to introducing our computational screening procedure, in this presentation we will summarize our results for solid systems composed by alkali and alkaline earth metal oxides, hydroxides, and carbon- ates/bicarbonates to validate our methodology. Additionally, applications of our computational method to mixed solid systems of Li2O with SiO2/ZrO2 with different mixing ratios, our preliminary results showed that increasing the Li2O/SiO2 ratio in
Theoretical Astrophysics at Fermilab
2004-01-01
The Theoretical Astrophysics Group works on a broad range of topics ranging from string theory to data analysis in the Sloan Digital Sky Survey. The group is motivated by the belief that a deep understanding of fundamental physics is necessary to explain a wide variety of phenomena in the universe. During the three years 2001-2003 of our previous NASA grant, over 120 papers were written; ten of our postdocs went on to faculty positions; and we hosted or organized many workshops and conferences. Kolb and collaborators focused on the early universe, in particular and models and ramifications of the theory of inflation. They also studied models with extra dimensions, new types of dark matter, and the second order effects of super-horizon perturbations. S tebbins, Frieman, Hui, and Dodelson worked on phenomenological cosmology, extracting cosmological constraints from surveys such as the Sloan Digital Sky Survey. They also worked on theoretical topics such as weak lensing, reionization, and dark energy. This work has proved important to a number of experimental groups [including those at Fermilab] planning future observations. In general, the work of the Theoretical Astrophysics Group has served as a catalyst for experimental projects at Fennilab. An example of this is the Joint Dark Energy Mission. Fennilab is now a member of SNAP, and much of the work done here is by people formerly working on the accelerator. We have created an environment where many of these people made transition from physics to astronomy. We also worked on many other topics related to NASA s focus: cosmic rays, dark matter, the Sunyaev-Zel dovich effect, the galaxy distribution in the universe, and the Lyman alpha forest. The group organized and hosted a number of conferences and workshop over the years covered by the grant. Among them were:
Institute for Theoretical Physics
Energy Technology Data Exchange (ETDEWEB)
Giddings, S.B.; Ooguri, H.; Peet, A.W.; Schwarz, J.H.
1998-06-01
String theory is the only serious candidate for a unified description of all known fundamental particles and interactions, including gravity, in a single theoretical framework. Over the past two years, activity in this subject has grown rapidly, thanks to dramatic advances in understanding the dynamics of supersymmetric field theories and string theories. The cornerstone of these new developments is the discovery of duality which relates apparently different string theories and transforms difficult strongly coupled problems of one theory into weakly coupled problems of another theory.
Theoretical astrophysics an introduction
Bartelmann, Matthias
2013-01-01
A concise yet comprehensive introduction to the central theoretical concepts of modern astrophysics, presenting hydrodynamics, radiation, and stellar dynamics all in one textbook. Adopting a modular structure, the author illustrates a small number of fundamental physical methods and principles, which are sufficient to describe and understand a wide range of seemingly very diverse astrophysical phenomena and processes. For example, the formulae that define the macroscopic behavior of stellar systems are all derived in the same way from the microscopic distribution function. This function it
Shivamoggi, Bhimsen K
1998-01-01
"Although there are many texts and monographs on fluid dynamics, I do not know of any which is as comprehensive as the present book. It surveys nearly the entire field of classical fluid dynamics in an advanced, compact, and clear manner, and discusses the various conceptual and analytical models of fluid flow." - Foundations of Physics on the first edition. Theoretical Fluid Dynamics functions equally well as a graduate-level text and a professional reference. Steering a middle course between the empiricism of engineering and the abstractions of pure mathematics, the author focuses
Theoretical Optics An Introduction
Römer, Hartmann
2004-01-01
Starting from basic electrodynamics, this volume provides a solid, yet concise introduction to theoretical optics, containing topics such as nonlinear optics, light-matter interaction, and modern topics in quantum optics, including entanglement, cryptography, and quantum computation. The author, with many years of experience in teaching and research, goes way beyond the scope of traditional lectures, enabling readers to keep up with the current state of knowledge. Both content and presentation make it essential reading for graduate and phD students as well as a valuable reference for researche
Institute of Scientific and Technical Information of China (English)
徐志广; 古国榜; 刘海洋
2007-01-01
Crystal structure of dibenzothiophene sulfoxide was obtained by the X-ray diffraction method. It crystallizes in triclinic, space group P-1 with a=0.84712 nm, b=0.94137 nm, c=1.20380 nm,α=97.866 °,β=106.2630 °,γ=96.437 °, V=0.9014 nm3, R1 (all data)= 0.0348 and ωR2(all data) = 0.0814. It exhibits a longer S=O bond length, which meaning a weak S=O bond of dibenzothiophene sulfoxide . With antiparallel-sandwich geometry of III and antiparallel-displaced geometry of IV, the crystals constructed with III and IV alternately following π-π stacking interactions. Theoretical calculations on dibenzothiophene sulfoxide had been carried out by BHandH method at the 6-31+G**level can give reasonable results for III, IV and V structure, furthermore, the Eπ-π, π-π stacking interaction energies, are -36.06, -39.83 and -75.72 kJ/mol respectively. The π-π stacking stability of III and IV may be understood by the matching of atoms’ charge populations of between two II structures.% 采用X射线衍射法测定二苯并噻吩亚砜单晶结构,发现晶体中二苯并噻吩亚砜分子以反平行三明治式的结构III和反平行位移式的结构IV两种堆砌方式交替堆砌形成有序π-π堆积晶体.二苯并噻吩亚砜单晶结构属于三斜型,空间群为P-1,晶体参数为：a=0.84712 nm, b=0.94137 nm, c=1.20380 nm,α=97.866°,β=106.2630°,γ=96.437°, V=0.9014 nm3, R1(全部数据)=0.0348和ωR2(全部数据)=0.0814.利用BHandH/6-31+G**方法计算了二苯并噻吩亚砜分子间的π-π堆积作用,III和IV堆砌模式的π-π堆积效应作用能相当大,其计算值分别为-36.06 kJ/mol和-39.83 kJ/mol,电荷布局表明正负电荷匹配是稳定晶体π-π堆积体系的重要因素.
Theoretical and Experimental Physics
Energy Technology Data Exchange (ETDEWEB)
Nelson, Ann E. [Univ. of Washington, Seattle, WA (United States); Ellis, Stephen D. [Univ. of Washington, Seattle, WA (United States); Karch, Andreas [Univ. of Washington, Seattle, WA (United States); Rosenberg, Leslie [Univ. of Washington, Seattle, WA (United States); Sharpe, Stephene R. [Univ. of Washington, Seattle, WA (United States); Wilkes, R. Jeffrey [Univ. of Washington, Seattle, WA (United States); Yaffe, Laurence G. [Univ. of Washington, Seattle, WA (United States)
2015-04-07
We report on progress towards finding axion dark matter, neutrino oscillation parameters, Use of the gravity/gauge correspondence to to calculations in strongly coupled systems, use of jet substructure to search for new physics, use of lattice QCD to compute weak matrix elements, constraints on dark matter interactions from neutron stars, exotic Higgs searches, and new dark matter models.
Energy Technology Data Exchange (ETDEWEB)
Gottlieb, S.A.
1990-05-01
My research in lattice gauge theory during the past year is described. Several projects were completed dealing with QCD simulations including dynamical fermions. Under the DOE Grand Challenge program, a large scale calculation of the QCD spectrum with two light flavors of dynamical staggered quarks was carried out. This calculation is one of the most significant efforts to data to take into account the effects of dynamical fermions. Smaller lattice spacing and lighter quark masses were used than in previous attempts. QCD thermodynamics was studied on the ST-100 array processor and on an ETA supercomputer at the John von Neumann Supercomputer Center. On the ST-100, a study with two flavors of dynamical staggered quarks with am{sub q} = 0.025 and 0.0125 was carried out on a 12{sup 3} {times} 8 lattice. These results give a rough estimate of the crossover couplings where we see the restoration of chiral symmetry. A study of QCD with dynamical Wilson fermions was carried out with N{sub t} = 4 to try to bring the study of QCD with dynamical Wilson fermions to the level that has been attained with staggered fermions over the past two years. We have calculated screening lengths to elucidate the properties of the high temperature phase. In the pure gluon theory, claims that the finite temperature deconfinement transition is second order, rather than first order, were investigated using a finite size scaling analysis. Our results support a first order transition. Finally, work was done to port computer code to new environments involving parallelism in order to pursue more ambitious calculations on more powerful hardware than the ST-100 and ETA10 used for the calculations reported here.
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
This article presents a theoretical investigation on the steady-state natural circulation characteristics of a new type of pressurized water reactor. Through numerically solving the one-dimensional steady-state single-phase conservative equations for the primary circuit and the steady-state two-phase drift-flux conservative equations for the secondary side of the steam generator, the natural circulation characteristics were studied. On the basis of the preliminary calculation analysis, it was found that natural circulation mass flow rate was proportional to the exponential function of the power and that the value of the exponent is related to the operating conditions of the secondary side of the steam generator. The higher the outlet pressure of the secondary side of the steam generator, the higher the primary natural circulation mass flow rate. The larger height difference between the core center and the steam generator center is favorable for the heat removal capacity of the natural circulation.
UVISS preliminary visibility analysis
DEFF Research Database (Denmark)
Betto, Maurizio
1998-01-01
The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part of the w......The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part...
FUEL HANDLING FACILITY BACKUP CENTRAL COMMUNICATIONS ROOM SPACE REQUIREMENTS CALCULATION
Energy Technology Data Exchange (ETDEWEB)
B. SZALEWSKI
2005-03-22
The purpose of the Fuel Handling Facility Backup Central Communications Room Space Requirements Calculation is to determine a preliminary estimate of the space required to house the backup central communications room in the Fuel Handling Facility (FHF). This room provides backup communications capability to the primary communication systems located in the Central Control Center Facility. This calculation will help guide FHF designers in allocating adequate space for communications system equipment in the FHF. This is a preliminary calculation determining preliminary estimates based on the assumptions listed in Section 4. As such, there are currently no limitations on the use of this preliminary calculation. The calculations contained in this document were developed by Design and Engineering and are intended solely for the use of Design and Engineering in its work regarding the FHF Backup Central Communications Room Space Requirements. Yucca Mountain Project personnel from Design and Engineering should be consulted before the use of the calculations for purposes other than those stated herein or use by individuals other than authorized personnel in Design and Engineering.
Theoretical study of n-alkane adsorption on metal surfaces
DEFF Research Database (Denmark)
Morikawa, Yoshitada; Ishii, Hisao; Seki, Kazuhiko
2004-01-01
The interaction between n-alkane and metal surfaces has been studied by means of density-functional theoretical calculations within a generalized gradient approximation (GGA). We demonstrate that although the GGA cannot reproduce the physisorption energy well, our calculations can reproduce the e...
Theoretical Analysis of Shrouded Horizontal Axis Wind Turbines
Directory of Open Access Journals (Sweden)
Tariq Abdulsalam Khamlaj
2017-01-01
Full Text Available Numerous analytical studies for power augmentation systems can be found in the literature with the goal to improve the performance of wind turbines by increasing the energy density of the air at the rotor. All methods to date are only concerned with the effects of a diffuser as the power augmentation, and this work extends the semi-empirical shrouded wind turbine model introduced first by Foreman to incorporate a converging-diverging nozzle into the system. The analysis is based on assumptions and approximations of the conservation laws to calculate optimal power coefficients and power extraction, as well as augmentation ratios. It is revealed that the power enhancement is proportional to the mass stream rise produced by the nozzle diffuser-augmented wind turbine (NDAWT. Such mass flow rise can only be accomplished through two essential principles: the increase in the area ratios and/or by reducing the negative back pressure at the exit. The thrust coefficient for optimal power production of a conventional bare wind turbine is known to be 8/9, whereas the theoretical analysis of the NDAWT predicts an ideal thrust coefficient either lower or higher than 8/9 depending on the back pressure coefficient at which the shrouded turbine operates. Computed performance expectations demonstrate a good agreement with numerical and experimental results, and it is demonstrated that much larger power coefficients than for traditional wind turbines are achievable. Lastly, the developed model is very well suited for the preliminary design of a shrouded wind turbine where typically many trade-off studies need to be conducted inexpensively.
Theoretical Particle Astrophysics
Energy Technology Data Exchange (ETDEWEB)
Kamionkowski, Marc
2013-08-07
Abstract: Theoretical Particle Astrophysics The research carried out under this grant encompassed work on the early Universe, dark matter, and dark energy. We developed CMB probes for primordial baryon inhomogeneities, primordial non-Gaussianity, cosmic birefringence, gravitational lensing by density perturbations and gravitational waves, and departures from statistical isotropy. We studied the detectability of wiggles in the inflation potential in string-inspired inflation models. We studied novel dark-matter candidates and their phenomenology. This work helped advance the DoE's Cosmic Frontier (and also Energy and Intensity Frontiers) by finding synergies between a variety of different experimental efforts, by developing new searches, science targets, and analyses for existing/forthcoming experiments, and by generating ideas for new next-generation experiments.
Theoretical physics 5 thermodynamics
Nolting, Wolfgang
2017-01-01
This concise textbook offers a clear and comprehensive introduction to thermodynamics, one of the core components of undergraduate physics courses. It follows on naturally from the previous volumes in this series, defining macroscopic variables, such as internal energy, entropy and pressure,together with thermodynamic principles. The first part of the book introduces the laws of thermodynamics and thermodynamic potentials. More complex themes are covered in the second part of the book, which describes phases and phase transitions in depth. Ideally suited to undergraduate students with some grounding in classical mechanics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful German editions, the eight volumes of this series cove...
Theoretical Molecular Biophysics
Scherer, Philipp
2010-01-01
"Theoretical Molecular Biophysics" is an advanced study book for students, shortly before or after completing undergraduate studies, in physics, chemistry or biology. It provides the tools for an understanding of elementary processes in biology, such as photosynthesis on a molecular level. A basic knowledge in mechanics, electrostatics, quantum theory and statistical physics is desirable. The reader will be exposed to basic concepts in modern biophysics such as entropic forces, phase separation, potentials of mean force, proton and electron transfer, heterogeneous reactions coherent and incoherent energy transfer as well as molecular motors. Basic concepts such as phase transitions of biopolymers, electrostatics, protonation equilibria, ion transport, radiationless transitions as well as energy- and electron transfer are discussed within the frame of simple models.
Social Security: Theoretical Aspects
Directory of Open Access Journals (Sweden)
O. I. Kashnik
2013-01-01
Full Text Available The paper looks at the phenomena of security and social security from the philosophical, sociological and psychological perspective. The undertaken analysis of domestic and foreign scientific materials demonstrates the need for interdisciplinary studies, including pedagogy and education, aimed at developing the guidelines for protecting the social system from destruction. The paper defines the indicators, security level indices and their assessment methods singled out from the analytical reports and security studies by the leading Russian sociological centers and international expert organizations, including the United Nations.The research is aimed at finding out the adequate models of personal and social security control systems at various social levels. The theoretical concepts can be applied by the teachers of the Bases of Life Safety course, the managers and researches developing the assessment criteria and security indices of educational environment evaluation, as well as the methods of diagnostics and expertise of educational establishments from the security standpoint.
Theoretical physics 3 electrodynamics
Nolting, Wolfgang
2016-01-01
This textbook offers a clear and comprehensive introduction to electrodynamics, one of the core components of undergraduate physics courses. It follows on naturally from the previous volumes in this series. The first part of the book describes the interaction of electric charges and magnetic moments by introducing electro- and magnetostatics. The second part of the book establishes deeper understanding of electrodynamics with the Maxwell equations, quasistationary fields and electromagnetic fields. All sections are accompanied by a detailed introduction to the math needed. Ideally suited to undergraduate students with some grounding in classical and analytical mechanics, the book is enhanced throughout with learning features such as boxed inserts and chapter summaries, with key mathematical derivations highlighted to aid understanding. The text is supported by numerous worked examples and end of chapter problem sets. About the Theoretical Physics series Translated from the renowned and highly successful Germa...
Validation of fluorescence transition probability calculations
Pia, M G; Sudhaka, Manju
2009-01-01
A systematic and quantitative validation of the K and L shell X-ray transition probability calculations according to different theoretical methods has been performed against experimental data. This study is relevant to the optimization of data libraries used by software systems, namely Monte Carlo codes, dealing with X-ray fluorescence. The results support the adoption of transition probabilities calculated according to the Hartree-Fock approach, which manifest better agreement with experimental measurements than calculations based on the Hartree-Slater method.
UVISS preliminary visibility analysis
DEFF Research Database (Denmark)
Betto, Maurizio
1998-01-01
The goal of this work is to obtain a preliminary assessment of the sky visibility for anastronomical telescope located on the express pallet of the International SpaceStation (ISS)} taking into account the major constraints imposed on the instrument by the ISSattitude and structure. Part...
Threlfall, John
2002-01-01
Suggests that strategy choice is a misleading characterization of efficient mental calculation and that teaching mental calculation methods as a whole is not conducive to flexibility. Proposes an alternative in which calculation is thought of as an interaction between noticing and knowledge. Presents an associated teaching approach to promote…
Geochemical Calculations Using Spreadsheets.
Dutch, Steven Ian
1991-01-01
Spreadsheets are well suited to many geochemical calculations, especially those that are highly repetitive. Some of the kinds of problems that can be conveniently solved with spreadsheets include elemental abundance calculations, equilibrium abundances in nuclear decay chains, and isochron calculations. (Author/PR)
Autistic Savant Calendar Calculators.
Patti, Paul J.
This study identified 10 savants with developmental disabilities and an exceptional ability to calculate calendar dates. These "calendar calculators" were asked to demonstrate their abilities, and their strategies were analyzed. The study found that the ability to calculate dates into the past or future varied widely among these…
Theoretical study of a melting curve for tin
Institute of Scientific and Technical Information of China (English)
Xi Feng; Cai Ling-Cang
2009-01-01
The melting curve of Sn has been calculated using the dislocation-mediated melting model with the 'zone-linking method'. The results are in good agreement with the experimental data. According to our calculation, the melting temperature of γ-Sn at zero pressure is about 436 K obtained by the extrapolation of the method from the triple point of Sn. The results show that this calculation method is better than other theoretical methods for predicting the meltingcurve of polymorphic material Sn.
How Do Calculators Calculate Trigonometric Functions?
Underwood, Jeremy M.; Edwards, Bruce H.
How does your calculator quickly produce values of trigonometric functions? You might be surprised to learn that it does not use series or polynomial approximations, but rather the so-called CORDIC method. This paper will focus on the geometry of the CORDIC method, as originally developed by Volder in 1959. This algorithm is a wonderful…
A theoretical evaluation of possible transition metal electro-catalysts for N2 reduction
DEFF Research Database (Denmark)
Skulason, Egill; Bligaard, Thomas; Gudmundsdottir, Sigrıdur
2012-01-01
Theoretical studies of the possibility of forming ammonia electrochemically at ambient temperature and pressure are presented. Density functional theory calculations were used in combination with the computational standard hydrogen electrode to calculate the free energy profile for the reduction ...
TO THE CALCULATION OF THE ECONOMIC POTENTIAL OF WIND ENERGY AND THE CHOICE OF WIND POWER PLANTS
Directory of Open Access Journals (Sweden)
Vinnikov A. V.
2016-01-01
Full Text Available To determine the feasibility of using PV systems we should assess the economic efficiency of wind energy in the region. At the same time, the first step should be an analysis of upper-air and power characteristics of the wind. The next stage is to determine the energy source of wind power (theoretical, technical and economic potential. The basic approach to the calculation of economic indicators should include a determination of the effectiveness of wind power installations in competition with traditional energy sources in a particular region. There are important following indicators: the payback period and economic efficiency. If the economic potential of wind power satisfies the requirements, the next step is to study the technical requirements applicable to wind power stations. For a preliminary assessment of the terrain, the article discloses a sequence of events that must be performed to assess the effectiveness of the installation of wind power systems. We have listed advantages and disadvantages of the main types of wind power plants, and other ramifications of choosing of basic functional units. The considered in an article analytical expressions for calculating the evaluation of economic efficiency of wind energy, the technical requirements for the basic parameters of wind turbines and their main advantages, disadvantages and features the work will allow at the design stage to carry out a preliminary assessment of effectiveness of the wind power stations for a particular region and locality, specific types consumers in view of their modes of operation and the quality requirements of electricity
Preliminary hazards analysis -- vitrification process
Energy Technology Data Exchange (ETDEWEB)
Coordes, D.; Ruggieri, M.; Russell, J.; TenBrook, W.; Yimbo, P. [Science Applications International Corp., Pleasanton, CA (United States)
1994-06-01
This paper presents a Preliminary Hazards Analysis (PHA) for mixed waste vitrification by joule heating. The purpose of performing a PHA is to establish an initial hazard categorization for a DOE nuclear facility and to identify those processes and structures which may have an impact on or be important to safety. The PHA is typically performed during and provides input to project conceptual design. The PHA is then followed by a Preliminary Safety Analysis Report (PSAR) performed during Title 1 and 2 design. The PSAR then leads to performance of the Final Safety Analysis Report performed during the facility`s construction and testing. It should be completed before routine operation of the facility commences. This PHA addresses the first four chapters of the safety analysis process, in accordance with the requirements of DOE Safety Guidelines in SG 830.110. The hazards associated with vitrification processes are evaluated using standard safety analysis methods which include: identification of credible potential hazardous energy sources; identification of preventative features of the facility or system; identification of mitigative features; and analyses of credible hazards. Maximal facility inventories of radioactive and hazardous materials are postulated to evaluate worst case accident consequences. These inventories were based on DOE-STD-1027-92 guidance and the surrogate waste streams defined by Mayberry, et al. Radiological assessments indicate that a facility, depending on the radioactive material inventory, may be an exempt, Category 3, or Category 2 facility. The calculated impacts would result in no significant impact to offsite personnel or the environment. Hazardous materials assessment indicates that a Mixed Waste Vitrification facility will be a Low Hazard facility having minimal impacts to offsite personnel and the environment.
Theoretical Approaches to Coping
Directory of Open Access Journals (Sweden)
Sofia Zyga
2013-01-01
Full Text Available Introduction: Dealing with stress requires conscious effort, it cannot be perceived as equal to individual's spontaneous reactions. The intentional management of stress must not be confused withdefense mechanisms. Coping differs from adjustment in that the latter is more general, has a broader meaning and includes diverse ways of facing a difficulty.Aim: An exploration of the definition of the term "coping", the function of the coping process as well as its differentiation from other similar meanings through a literature review.Methodology: Three theoretical approaches of coping are introduced; the psychoanalytic approach; approaching by characteristics; and the Lazarus and Folkman interactive model.Results: The strategic methods of the coping approaches are described and the article ends with a review of the approaches including the functioning of the stress-coping process , the classificationtypes of coping strategies in stress-inducing situations and with a criticism of coping approaches.Conclusions: The comparison of coping in different situations is difficult, if not impossible. The coping process is a slow process, so an individual may select one method of coping under one set ofcircumstances and a different strategy at some other time. Such selection of strategies takes place as the situation changes.
Energy Technology Data Exchange (ETDEWEB)
Nagao, Yoshiharu [Japan Atomic Energy Research Inst., Oarai, Ibaraki (Japan). Oarai Research Establishment
1998-03-01
In material testing reactors like the JMTR (Japan Material Testing Reactor) of 50 MW in Japan Atomic Energy Research Institute, the neutron flux and neutron energy spectra of irradiated samples show complex distributions. It is necessary to assess the neutron flux and neutron energy spectra of an irradiation field by carrying out the nuclear calculation of the core for every operation cycle. In order to advance core calculation, in the JMTR, the application of MCNP to the assessment of core reactivity and neutron flux and spectra has been investigated. In this study, in order to reduce the time for calculation and variance, the comparison of the results of the calculations by the use of K code and fixed source and the use of Weight Window were investigated. As to the calculation method, the modeling of the total JMTR core, the conditions for calculation and the adopted variance reduction technique are explained. The results of calculation are shown. Significant difference was not observed in the results of neutron flux calculations according to the difference of the modeling of fuel region in the calculations by K code and fixed source. The method of assessing the results of neutron flux calculation is described. (K.I.)
A Theoretical Analysis of Ball Spinning
Institute of Scientific and Technical Information of China (English)
无
2002-01-01
As a special method of manufacturing thin wall tubes, the ball spinning process has been used for nearly 30 years because of its less investment of equipment, higher precision, and more perfect properties of products. However, the application is limited since the process parameters are determined based on empirical data and laboratory experiments for lack of a whole theoretical analysis. In this paper, some basic parameters such as the force and power parameters have been studied based on an analysis of geometry and mechanics of the process. The calculation of forming forces and the selection of the working angle are carried out. At the end, a perfect comparison between the results of the experiments and the theoretical analysis is made.
Beasley, W. H.; Petersen, D.
2013-12-01
The preliminary breakdown phase of a negative cloud-to-ground lightning flash was observed in detail. Observations were made with a Photron SA1.1 high-speed video camera operating at 9,000 frames per second, fast optical sensors, a flat-plate electric field antenna covering the SLF to MF band, and VHF and UHF radio receivers with bandwidths of 20 MHz. Bright stepwise extensions of a negative leader were observed at an altitude of 8 km during the first few milliseconds of the flash, and were coincident with bipolar electric field pulses called 'characteristic pulses'. The 2-D step lengths of the preliminary processes were in excess of 100 meters, with some 2-D step lengths in excess of 200 meters. Smaller and shorter unipolar electric field pulses were superposed onto the bipolar electric field pulses, and were coincident with VHF and UHF radio pulses. After a few milliseconds, the emerging negative stepped leader system showed a marked decrease in luminosity, step length, and propagation velocity. Details of these events will be discussed, including the possibility that the preliminary breakdown phase consists not of a single developing lightning leader system, but of multiple smaller lightning leader systems that eventually join together into a single system.
Institute of Scientific and Technical Information of China (English)
冉勇; 秦家银; 朱昌平; 李太全; 陶少华
2001-01-01
We have made a systematic study in optically pumped submillimeter wave laser. In this paper, expound a semiclassical density matrix theory, it was used by Author in theoretical study of miniature optically pumped submillimeter wave laser.%该作者曾对光泵亚毫米波激光作过系统深入地的研究。重点论述在小型光泵亚毫米波激光的理论研究中所应用的量子系统的半经典密度矩阵理论。
DEFF Research Database (Denmark)
Bahr, Patrick; Hutton, Graham
2015-01-01
In this article, we present a new approach to the problem of calculating compilers. In particular, we develop a simple but general technique that allows us to derive correct compilers from high-level semantics by systematic calculation, with all details of the implementation of the compilers...... falling naturally out of the calculation process. Our approach is based upon the use of standard equational reasoning techniques, and has been applied to calculate compilers for a wide range of language features and their combination, including arithmetic expressions, exceptions, state, various forms...
Radar Signature Calculation Facility
Federal Laboratory Consortium — FUNCTION: The calculation, analysis, and visualization of the spatially extended radar signatures of complex objects such as ships in a sea multipath environment and...
Electrical installation calculations basic
Kitcher, Christopher
2013-01-01
All the essential calculations required for basic electrical installation workThe Electrical Installation Calculations series has proved an invaluable reference for over forty years, for both apprentices and professional electrical installation engineers alike. The book provides a step-by-step guide to the successful application of electrical installation calculations required in day-to-day electrical engineering practice. A step-by-step guide to everyday calculations used on the job An essential aid to the City & Guilds certificates at Levels 2 and 3Fo
Electrical installation calculations advanced
Kitcher, Christopher
2013-01-01
All the essential calculations required for advanced electrical installation workThe Electrical Installation Calculations series has proved an invaluable reference for over forty years, for both apprentices and professional electrical installation engineers alike. The book provides a step-by-step guide to the successful application of electrical installation calculations required in day-to-day electrical engineering practiceA step-by-step guide to everyday calculations used on the job An essential aid to the City & Guilds certificates at Levels 2 and 3For apprentices and electrical installatio
Electronics Environmental Benefits Calculator
U.S. Environmental Protection Agency — The Electronics Environmental Benefits Calculator (EEBC) was developed to assist organizations in estimating the environmental benefits of greening their purchase,...
Methods for Melting Temperature Calculation
Hong, Qi-Jun
Melting temperature calculation has important applications in the theoretical study of phase diagrams and computational materials screenings. In this thesis, we present two new methods, i.e., the improved Widom's particle insertion method and the small-cell coexistence method, which we developed in order to capture melting temperatures both accurately and quickly. We propose a scheme that drastically improves the efficiency of Widom's particle insertion method by efficiently sampling cavities while calculating the integrals providing the chemical potentials of a physical system. This idea enables us to calculate chemical potentials of liquids directly from first-principles without the help of any reference system, which is necessary in the commonly used thermodynamic integration method. As an example, we apply our scheme, combined with the density functional formalism, to the calculation of the chemical potential of liquid copper. The calculated chemical potential is further used to locate the melting temperature. The calculated results closely agree with experiments. We propose the small-cell coexistence method based on the statistical analysis of small-size coexistence MD simulations. It eliminates the risk of a metastable superheated solid in the fast-heating method, while also significantly reducing the computer cost relative to the traditional large-scale coexistence method. Using empirical potentials, we validate the method and systematically study the finite-size effect on the calculated melting points. The method converges to the exact result in the limit of a large system size. An accuracy within 100 K in melting temperature is usually achieved when the simulation contains more than 100 atoms. DFT examples of Tantalum, high-pressure Sodium, and ionic material NaCl are shown to demonstrate the accuracy and flexibility of the method in its practical applications. The method serves as a promising approach for large-scale automated material screening in which
Experimental and theoretical study on hollow-cone spray
Chang, Keh-Chin; Wang, Muh-Rong; Wu, Wen-Jing; Hong, Chia-Hong
1993-02-01
A theoretical and experimental investigation has been conducted to study the two-phase turbulent structure in an isothermal hollow-cone spray. Mean and fluctuating velocity components, drop number density, as well as drop-size distribution were measured with a nonintrusive diagnostic tool, a two-component phase Doppler particle analyzer. Complete initial conditions required for theoretical calculations were also provided with measurements. Theoretical calculations were made with an Eulerian-Lagrangian formulism. Turbulent dispersion effects were numerically simulated using a Monte Carlo method. Turbulence modulation effects were also taken into account in the modeling. The well-defined experimental data were used to assess the accuracy of the resultant Eulerian-Lagrangian model. Comparisons showed that the theoretical predictions, based upon the Eulerian-Lagrangian model, yielded reasonable agreement with the experimental data. The improvements made by inclusion of the selected turbulence modulation model were insignificant in this work.
The Basic Theoretical Framework
Loeb, Abraham
Cosmology is by now a mature experimental science. We are privileged to live at a time when the story of genesis (how the Universe started and developed) can be critically explored by direct observations. Looking deep into the Universe through powerful telescopes, we can see images of the Universe when it was younger because of the finite time it takes light to travel to us from distant sources. Existing data sets include an image of the Universe when it was 0.4 million years old (in the form of the cosmic microwave background), as well as images of individual galaxies when the Universe was older than a billion years. But there is a serious challenge: in between these two epochs was a period when the Universe was dark, stars had not yet formed, and the cosmic microwave background no longer traced the distribution of matter. And this is precisely the most interesting period, when the primordial soup evolved into the rich zoo of objects we now see. The observers are moving ahead along several fronts. The first involves the construction of large infrared telescopes on the ground and in space, that will provide us with new photos of the first galaxies. Current plans include ground-based telescopes which are 24-42 m in diameter, and NASA's successor to the Hubble Space Telescope, called the James Webb Space Telescope. In addition, several observational groups around the globe are constructing radio arrays that will be capable of mapping the three-dimensional distribution of cosmic hydrogen in the infant Universe. These arrays are aiming to detect the long-wavelength (redshifted 21-cm) radio emission from hydrogen atoms. The images from these antenna arrays will reveal how the non-uniform distribution of neutral hydrogen evolved with cosmic time and eventually was extinguished by the ultra-violet radiation from the first galaxies. Theoretical research has focused in recent years on predicting the expected signals for the above instruments and motivating these ambitious
Theoretically Optimal Distributed Anomaly Detection
National Aeronautics and Space Administration — A novel general framework for distributed anomaly detection with theoretical performance guarantees is proposed. Our algorithmic approach combines existing anomaly...
Calculators and Polynomial Evaluation.
Weaver, J. F.
The intent of this paper is to suggest and illustrate how electronic hand-held calculators, especially non-programmable ones with limited data-storage capacity, can be used to advantage by students in one particular aspect of work with polynomial functions. The basic mathematical background upon which calculator application is built is summarized.…
Modeling of alkynes: synthesis and theoretical properties
Directory of Open Access Journals (Sweden)
Renato Rosseto
2003-06-01
Full Text Available In this paper we present the synthesis and simulation of alkynes derivatives. Semiempirical calculations were carried out for the ground and first excited states, including the spectroscopic properties of the absorption and emission (fluorescence and phosphorescence spectra by INDO/S-CI and DNdM-INDO/S-CI methods with geometries fully optimized by PM3/CI. The fact that the theoretical spectra are in accord with the experimental absorption spectra gives us a new possible approach on how structure modifications could affect the non-linear optical properties of alkynes.
Preliminary evaluation of diabatic heating distribution from FGGE level 3b analysis data
Kasahara, A.; Mizzi, A. P.
1985-01-01
A method is presented for calculating the global distribution of diabatic heating rate. Preliminary results of global heating rate evaluated from the European center for Medium Range Weather Forecasts Level IIIb analysis data is also presented.
The friction of polymers around Tg,Tm : Preliminary results
DEFF Research Database (Denmark)
Sivebæk, Ion Marius; Samoilov, V N; Persson, B N J
We present Molecular Dynamics calculations involving polymers of different lengths. Polymers with lengths from 20 to 1400 carbon atoms are considered. The systems are able to simulate friction between polymer surfaces and polymer against metal. The results we present are very preliminary...
Quantum chemical calculations of glycine glutaric acid
Arioǧlu, ćaǧla; Tamer, Ömer; Avci, Davut; Atalay, Yusuf
2017-02-01
Density functional theory (DFT) calculations of glycine glutaric acid were performed by using B3LYP levels with 6-311++G(d,p) basis set. The theoretical structural parameters such as bond lengths and bond angles are in a good agreement with the experimental values of the title compound. HOMO and LUMO energies were calculated, and the obtained energy gap shows that charge transfer occurs in the title compound. Vibrational frequencies were calculated and compare with experimental ones. 3D molecular surfaces of the title compound were simulated using the same level and basis set. Finally, the 13C and 1H NMR chemical shift values were calculated by the application of the gauge independent atomic orbital (GIAO) method.
Theoretical study of the NO beta system
Langhoff, Stephen R.; Partridge, Harry; Bauschlicher, Charles W., Jr.; Komornicki, Andrew
1991-01-01
A theoretical determination of the transition moment functions (TMFs) for the beta system of NO is presented. High levels of correlation treatment are required to show the changing degree of Rydberg character in the B2II with decreasing r values. The state-averaged complete-active-space self-consistent-field multireference configuration-interaction method is used for the determination. Previous lifetime measurements made with laser-induced fluorescence, varying between 2 and 0.85 microns, are discussed in terms of the calculated lifetimes for v-prime values 0-6, which vary from 2.12-1.17 microns. When larger r values are used for the transition moment function, the calculated lifetimes correlate with experimental lifetimes. The Einstein coefficients agree with experimental results, although limitations in the calibration of the spectrometer can account for systematic differences. The correlation with earlier experimental results suggests that radiative lifetimes are in the range of 1-2 microns.
Theoretical study on spherical proton emission
Institute of Scientific and Technical Information of China (English)
无
2009-01-01
The proton radioactivity half-lives of spherical proton emitters are investigated within a generalized liquid drop model(GLDM),including the proximity effects between nuclei in a neck and the mass and charge asymmetry.The penetrability is calculated in the WKB approximation and the assault frequency is estimated by the quantum mechanism method considering the structure of the parent nucleus.The spectroscopic factor is taken into account in half-life calculation,which is obtained by employing the relativistic mean field(RMF) theory.The half-lives within the GLDM are compared with the experimental data and other theoretical values.The results show that the GLDM works quite well for spherical proton emitters when the assault frequency is estimated by the quantum mechanical method and the spectroscopic factor is considered.
Theoretical study on spherical proton emission
Institute of Scientific and Technical Information of China (English)
ZHANG HongFei; WANG YongJia; DONG JianMin; LI JunQing
2009-01-01
The proton radioactivity half-lives of spherical proton emitters are investigated within a generalized liquid drop model (GLDM),including the proximity effects between nuclei in a neck and the mass and charge asymmetry.The penetrability is calculated in the WKB approximation and the assault frequency is estimated by the quantum mechanism method considering the structure of the parent nucleus.The spectroscopic factor is taken into account in half-life calculation,which is obtained by employing the relativistic mean field (RMF) theory.The half-lives within the GLDM are compared with the experimental data and other theoretical values.The results show that the GLDM works quite well for spherical proton emitters when the assault frequency is estimated by the quantum mechanical method and the spectroscopic factor is considered.
Biomechanics of injury prediction for anthropomorphic manikins - preliminary design considerations
Energy Technology Data Exchange (ETDEWEB)
Engin, A.E. [Univ. of South Alabama, Mobile, AL (United States)
1996-12-31
The anthropomorphic manikins are used in automobile safety research as well as in aerospace related applications. There is now a strong need to advance the biomechanics knowledge to determine appropriate criteria for injury likelihood prediction as functions of manikin-measured responses. In this paper, three regions of a manikin, namely, the head, knee joint, and lumbar spine are taken as examples to introduce preliminary design considerations for injury prediction by means of responses of theoretical models and strategically placed sensing devices.
Environmental Survey preliminary report
Energy Technology Data Exchange (ETDEWEB)
1988-04-01
This report presents the preliminary findings from the first phase of the Environmental Survey of the United States Department of Energy (DOE) Sandia National Laboratories conducted August 17 through September 4, 1987. The objective of the Survey is to identify environmental problems and areas of environmental risk associated with Sandia National Laboratories-Albuquerque (SNLA). The Survey covers all environmental media and all areas of environmental regulation. It is being performed in accordance with the DOE Environmental Survey Manual. This phase of the Survey involves the review of existing site environmental data, observations of the operations carried on at SNLA, and interviews with site personnel. 85 refs., 49 figs., 48 tabs.
Ruiz Volcano: Preliminary report
Ruiz Volcano, Colombia (4.88°N, 75.32°W). All times are local (= GMT -5 hours).An explosive eruption on November 13, 1985, melted ice and snow in the summit area, generating lahars that flowed tens of kilometers down flank river valleys, killing more than 20,000 people. This is history's fourth largest single-eruption death toll, behind only Tambora in 1815 (92,000), Krakatau in 1883 (36,000), and Mount Pelée in May 1902 (28,000). The following briefly summarizes the very preliminary and inevitably conflicting information that had been received by press time.
TINTE. Nuclear calculation theory description report
Energy Technology Data Exchange (ETDEWEB)
Gerwin, H.; Scherer, W.; Lauer, A. [Forschungszentrum Juelich GmbH (DE). Institut fuer Energieforschung (IEF), Sicherheitsforschung und Reaktortechnik (IEF-6); Clifford, I. [Pebble Bed Modular Reactor (Pty) Ltd. (South Africa)
2010-01-15
The Time Dependent Neutronics and Temperatures (TINTE) code system deals with the nuclear and the thermal transient behaviour of the primary circuit of the High-temperature Gas-cooled Reactor (HTGR), taking into consideration the mutual feedback effects in twodimensional axisymmetric geometry. This document contains a complete description of the theoretical basis of the TINTE nuclear calculation, including the equations solved, solution methods and the nuclear data used in the solution. (orig.)
Practical versus theoretical domestic energy consumption for space heating
Energy Technology Data Exchange (ETDEWEB)
Audenaert, A., E-mail: amaryllis.audenaert@artesis.be [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium); Department of Environment, Technology and Technology Management, University of Antwerp, Prinsstraat 13, B-2000 Antwerp (Belgium); Briffaerts, K. [Unit Transition Energy and Environment, VITO NV, Boeretang 200, B-2400 Mol (Belgium); Engels, L. [Department of Applied Engineering: Construction, Artesis University College of Antwerp, Paardenmarkt 92, B-2000 Antwerp (Belgium)
2011-09-15
Methods to calculate the theoretical energy consumption consider several things: the number of degree days per year that need to be compensated by heating, the characteristics of the dwelling, the number of occupants and the characteristics of the installation for space heating and sanitary hot water. However, these methods do not take into account consumer behaviour, which may affect the actual consumption. The theoretical calculation methods are based on assumptions and use a number of standardized parameters. The difference between the actual and the theoretical energy consumption, and the impact of the residents' behaviour on energy consumption, is analysed by means of a literature study and a practical research. An energy advice procedure (EAP) audit is executed in five dwellings, as well as a survey regarding the energy related behaviour of the households. The theoretically calculated consumption is compared with the billed actual energy consumption of the families. The results show some problems with the current procedure and give some options to improve it. Some research needs are identified to gain more insights in the influence of different behavioural factors on the actual energy use for heating. - Highlights: > The energy advice procedure (EAP) calculates the energy use for heating in dwellings. > Calculations are compared with the real energy use for 5 dwellings. > A survey on the occupants' behaviour is used to interpret the observed differences. > Default values used in the EAP can be very different from the observed behaviour.
Energy Technology Data Exchange (ETDEWEB)
Vahala, George M. [College of William and Mary, Williamsburg, VA (United States)
2013-12-31
with the electric field only being about three times higher than in the ideal case. Moreover, the quasi-optical grill was significantly fewer structural elements that the multijunction grill. Nevertheless there has not been much interest from experimental fusion groups to implementing these structures. Hence we have returned to optimizing the multijunction grill so that the large number of coupling matrix elements can be efficiently evaluated using symmetry arguments. In overdense plasmas, the standard electromagnetic waves cannot propagate into the plasma center, but are reflected at the plasma edge. By optimizing mode conversion processes (in particular, the O-X-B wave propagation of Ordinary Mode converting to an Extraordinary mode which then converts into an electrostatic Bernstein wave) one can excite within the plasma an electrostatic Bernstein wave that does not suffer density cutoffs and is absorbed on the electron cyclotron harmonics. Finally we have started looking at other mesoscopic lattice algorithms that involve unitary collision and streaming steps. Because these algorithms are unitary they can be run on quantum computers when they become available – unlike their computational cousin of lattice Boltzmann which is a purely classical code. These quantum lattice gas algorithms have been tested successfully on exact analytic soliton collision solution. These calculations are hoped to be able to study Bose Einstein condensed atomic gases and their ground states in an optical lattice.
AGING FACILITY CRITICALITY SAFETY CALCULATIONS
Energy Technology Data Exchange (ETDEWEB)
C.E. Sanders
2004-09-10
criticality safety results to support the preliminary design of the Aging Facility. As the ongoing design evolution remains fluid, the results from this design calculation should be evaluated for applicability to any new or modified design. Consequently, the results presented in this document are limited to the current design. The information contained in this document was developed by Environmental and Nuclear Engineering and is intended for the use of Design and Engineering in its work regarding the various criticality related activities performed in the Aging Facility. Yucca Mountain Project personnel from Environmental and Nuclear Engineering should be consulted before the use of the information for purposes other than those stated herein or use by individuals other than authorized personnel in Design and Engineering.
Interval arithmetic in calculations
Bairbekova, Gaziza; Mazakov, Talgat; Djomartova, Sholpan; Nugmanova, Salima
2016-10-01
Interval arithmetic is the mathematical structure, which for real intervals defines operations analogous to ordinary arithmetic ones. This field of mathematics is also called interval analysis or interval calculations. The given math model is convenient for investigating various applied objects: the quantities, the approximate values of which are known; the quantities obtained during calculations, the values of which are not exact because of rounding errors; random quantities. As a whole, the idea of interval calculations is the use of intervals as basic data objects. In this paper, we considered the definition of interval mathematics, investigated its properties, proved a theorem, and showed the efficiency of the new interval arithmetic. Besides, we briefly reviewed the works devoted to interval analysis and observed basic tendencies of development of integral analysis and interval calculations.
Unit Cost Compendium Calculations
U.S. Environmental Protection Agency — The Unit Cost Compendium (UCC) Calculations raw data set was designed to provide for greater accuracy and consistency in the use of unit costs across the USEPA...
EFFECTIVE DISCHARGE CALCULATION GUIDE
Institute of Scientific and Technical Information of China (English)
D.S.BIEDENHARN; C.R.THORNE; P.J.SOAR; R.D.HEY; C.C.WATSON
2001-01-01
This paper presents a procedure for calculating the effective discharge for rivers with alluvial channels.An alluvial river adjusts the bankfull shape and dimensions of its channel to the wide range of flows that mobilize the boundary sediments. It has been shown that time-averaged river morphology is adjusted to the flow that, over a prolonged period, transports most sediment. This is termed the effective discharge.The effective discharge may be calculated provided that the necessary data are available or can be synthesized. The procedure for effective discharge calculation presented here is designed to have general applicability, have the capability to be applied consistently, and represent the effects of physical processes responsible for determining the channel, dimensions. An example of the calculations necessary and applications of the effective discharge concept are presented.
DEFF Research Database (Denmark)
Frederiksen, Morten
2014-01-01
Williamson’s characterisation of calculativeness as inimical to trust contradicts most sociological trust research. However, a similar argument is found within trust phenomenology. This paper re-investigates Williamson’s argument from the perspective of Løgstrup’s phenomenological theory of trust....... Contrary to Williamson, however, Løgstrup’s contention is that trust, not calculativeness, is the default attitude and only when suspicion is awoken does trust falter. The paper argues that while Williamson’s distinction between calculativeness and trust is supported by phenomenology, the analysis needs...... to take actual subjective experience into consideration. It points out that, first, Løgstrup places trust alongside calculativeness as a different mode of engaging in social interaction, rather conceiving of trust as a state or the outcome of a decision-making process. Secondly, the analysis must take...
Magnetic Field Grid Calculator
National Oceanic and Atmospheric Administration, Department of Commerce — The Magnetic Field Properties Calculator will computes the estimated values of Earth's magnetic field(declination, inclination, vertical component, northerly...
Isomerization, Perturbations, Calculations and the S_{1} State of C_{2}H_{2}
Baraban, J. H.; Changala, P. B.; Berk, J. R. P.; Field, R. W.; Stanton, J. F.; Merer, A. J.
2013-06-01
Preliminary analysis of the energy region of the cis-trans isomerization transition state on the S_{1} surface of C_{2}H_{2} has revealed novel patterns and surprising perturbations, including unusually large (and high-order) anharmonicities, as well as K-staggerings of several vibrational levels. These effects complicate the analysis considerably, and require new models and calculations to account for and predict features of the observed spectra. The ˜{A}-˜{X} spectrum of acetylene has been studied both experimentally and theoretically for almost a century, and this cycle of unexpected phenomena eliciting innovative responses is found throughout its history. Especially in the last ten years, progress in understanding the S_{1} state rovibrational level structure and cis-trans isomerization has been accelerated by combining the information available from both ab initio computation and spectroscopic observations. The resulting dialogue has then frequently suggested fruitful avenues for further experiments and calculations. Current challenges and recent results in understanding the cis-trans isomerization transition state region will be discussed in this context.
Scientific calculating peripheral
Energy Technology Data Exchange (ETDEWEB)
Ethridge, C.D.; Nickell, J.D. Jr.; Hanna, W.H.
1979-09-01
A scientific calculating peripheral for small intelligent data acquisition and instrumentation systems and for distributed-task processing systems is established with a number-oriented microprocessor controlled by a single component universal peripheral interface microcontroller. A MOS/LSI number-oriented microprocessor provides the scientific calculating capability with Reverse Polish Notation data format. Master processor task definition storage, input data sequencing, computation processing, result reporting, and interface protocol is managed by a single component universal peripheral interface microcontroller.
Current interruption transients calculation
Peelo, David F
2014-01-01
Provides an original, detailed and practical description of current interruption transients, origins, and the circuits involved, and how they can be calculated Current Interruption Transients Calculationis a comprehensive resource for the understanding, calculation and analysis of the transient recovery voltages (TRVs) and related re-ignition or re-striking transients associated with fault current interruption and the switching of inductive and capacitive load currents in circuits. This book provides an original, detailed and practical description of current interruption transients, origins,
Shielding calculations for SSC
Energy Technology Data Exchange (ETDEWEB)
Van Ginneken, A.
1990-03-01
Monte Carlo calculations of hadron and muon shielding for SSC are reviewed with emphasis on their application to radiation safety and environmental protection. Models and algorithms for simulation of hadronic and electromagnetic showers, and for production and transport of muons in the TeV regime are briefly discussed. Capabilities and limitations of these calculations are described and illustrated with a few examples. 12 refs., 3 figs.
Geometric unsharpness calculations
Energy Technology Data Exchange (ETDEWEB)
Anderson, D.J. [International Training and Education Group (INTEG), Oakville, Ontario (Canada)
2008-07-15
The majority of radiographers' geometric unsharpness calculations are normally performed with a mathematical formula. However, a majority of codes and standards refer to the use of a nomograph for this calculation. Upon first review, the use of a nomograph appears more complicated but with a few minutes of study and practice it can be just as effective. A review of this article should provide enlightenment. (author)
Source and replica calculations
Energy Technology Data Exchange (ETDEWEB)
Whalen, P.P.
1994-02-01
The starting point of the Hiroshima-Nagasaki Dose Reevaluation Program is the energy and directional distributions of the prompt neutron and gamma-ray radiation emitted from the exploding bombs. A brief introduction to the neutron source calculations is presented. The development of our current understanding of the source problem is outlined. It is recommended that adjoint calculations be used to modify source spectra to resolve the neutron discrepancy problem.
INVAP's Nuclear Calculation System
Ignacio Mochi
2011-01-01
Since its origins in 1976, INVAP has been on continuous development of the calculation system used for design and optimization of nuclear reactors. The calculation codes have been polished and enhanced with new capabilities as they were needed or useful for the new challenges that the market imposed. The actual state of the code packages enables INVAP to design nuclear installations with complex geometries using a set of easy-to-use input files that minimize user errors due to confusion or mi...
Media’s role in pro-environmental practice changes – a theoretical and methodological framework
DEFF Research Database (Denmark)
Petersen, Lars Kjerulf
The aim of this paper is to present the theoretical framework and some preliminary findings from a research project investigating the metabolism of meanings between public communication and socio-material practice. The project seeks to integrate media analyses with practice theory and actor...
Directory of Open Access Journals (Sweden)
Carlos Mario Ruiz
2011-06-01
Full Text Available Las propiedades elásticas de la familia de los minerales isoestructurales Cu3VSe4, Cu3NbSe4 y Cu3TaSe4 han sido calculadas por primera vez usandoel estado del arte en cálculos atomísticos de primeros-principios, utilizandola Teoría de los Funcionales de la Densidad y la Aproximación del Gradiente Generalizado para el funcional de la energía de intercambio-correlación. Laspropiedades elásticas calculadas son el módulo volumétrico (B, las constantes elásticas (c11, c12 y c44, el factor de anisotropía de Zener (A, el módulo de cizalladura isotrópico (G, el módulo de Young (Y, y la razón de Poisson(ν. A través de estas cantidades también hemos calculado otras propiedades termodinámicas tales como la velocidad promedio del sonido transversal (st y longitudinal (sl y la temperatura de Debye (ΘD. Los valores calculados de B, c11, c12 y c44, G, Y , y ν nos llevan a la conclusión que estos compuestosson compresibles, frágiles y quebradizos.The elastic properties of the family of isostructural minerals Cu3VSe4, Cu3NbSe4 and Cu3TaSe4 have been calculated for the first time using the state of the art in first-principles atomistic calculations, using Density Functional Theory and the Generalized Gradient Approximation for the exchangecorrelation energy functional. The elastic properties calculated are bulk modulus (B, the elastic constants (c11, c12 and c44, the Zener anisotropy factor (A, the isotropic shear modulus (G, the Young modulus (Y , and the Poisson ratio (. By means of these quantities we also computed other thermodynamic properties such as the average transversal (st and longitudinal (sl sound velocities and the Debye temperature (D. The calculated values of B, c11, c12 and c44, G, Y and lead us to the conclusion that these compounds are compressible, fragile and brittle.
Development of a universal toric intraocular lens calculator
Hjelmstad, David; Sayegh, Samir I.
2014-02-01
We present a method for calculating the ideal toric lens to implant in astigmatic patients following cataract surgery. We show that the online calculators provided by major toric IOL manufacturers are insufficient for both theoretical and practical reasons. We reveal important theoretical shortcomings in their approach, illustrated by a number of cases which demonstrate how the approach can lead to errors in lens selection. Our approach combines the spherical and cylindrical power calculations into one, and allows for lens data from any manufacturer to be used, eliminating the reliance on multiple programs.
Theoretical and computational analyses of LNG evaporator
Chidambaram, Palani Kumar; Jo, Yang Myung; Kim, Heuy Dong
2017-04-01
Theoretical and numerical analysis on the fluid flow and heat transfer inside a LNG evaporator is conducted in this work. Methane is used instead of LNG as the operating fluid. This is because; methane constitutes over 80% of natural gas. The analytical calculations are performed using simple mass and energy balance equations. The analytical calculations are made to assess the pressure and temperature variations in the steam tube. Multiphase numerical simulations are performed by solving the governing equations (basic flow equations of continuity, momentum and energy equations) in a portion of the evaporator domain consisting of a single steam pipe. The flow equations are solved along with equations of species transport. Multiphase modeling is incorporated using VOF method. Liquid methane is the primary phase. It vaporizes into the secondary phase gaseous methane. Steam is another secondary phase which flows through the heating coils. Turbulence is modeled by a two equation turbulence model. Both the theoretical and numerical predictions are seen to match well with each other. Further parametric studies are planned based on the current research.
Theoretical chemistry advances and perspectives
Eyring, Henry
1980-01-01
Theoretical Chemistry: Advances and Perspectives, Volume 5 covers articles concerning all aspects of theoretical chemistry. The book discusses the mean spherical approximation for simple electrolyte solutions; the representation of lattice sums as Mellin-transformed products of theta functions; and the evaluation of two-dimensional lattice sums by number theoretic means. The text also describes an application of contour integration; a lattice model of quantum fluid; as well as the computational aspects of chemical equilibrium in complex systems. Chemists and physicists will find the book usef
Energy Technology Data Exchange (ETDEWEB)
Valette-Silver, J.N. (Univ. de Perpignan, France); Thompson, J.M.; Ball, J.W.
1981-01-01
The chemical compositions of waters collected from the Cerro Prieto geothermal production wells and hydrothermal emanations are different. Compared to the Cerro Prieto well waters, the surficial waters generally contain significantly less potassium, slightly less calcium and chloride, and significantly more magnesium and sulfate. In comparison to the unaltered sediments, the changes in the mineralogy of the altered sediments appear to be controlled by the type of emanation (well, spring, mud pot, geyser, fumarole, or cold pool). However, an increase in quartz and potassium feldspar percentages seems to be characteristic of the majority of the sediments in contact with geothermal fluids. Preliminary attempts to model the chemical processes occurring in the Cerro Prieto geothermal field using chemical equilibrium calculations are reported. For this purpose the chemical compositions of thermal waters (well and surficial emanation) were used as input data to make calculations with SOLMNEQ and WATEQ2 computer programs. Then the theoretical mineral composition of altered sediments was predicted and compared to the mineralogy actually observed in the solid samples.
Measurement of the density of animal bone by absorptiometry: some preliminary results
Energy Technology Data Exchange (ETDEWEB)
Gonnelli, Eduardo; Costa, Vladimir Eliodoro; Rezende, Marcos Antonio de; Hormaza, Joel Mesa; Machado, Vania Maria de Vasconcelos [UNESP, Botucatu, SP (Brazil)
2009-07-01
Full text: Measurement of bone mineral content for different bone types at various sites of the human body has been extensively studied in the last three decades. There are several methods for the determination of bone mineral density and strength by using non ionizing and ionizing radiation, as well as by other techniques, such as ultrasound. In humans, the accuracy and precision of those kind of measurement varies between the methods and, in all the cases, reference values are adopted as a function of sex, age and nutritional parameters. In this work, we have presented some preliminary results of the measurement of the density in animal bone obtained experimentally by absorptiometry, which is based on the fact that attenuation of a gamma ray beam is proportional to the coefficient of mass attenuation of an object in the path of the beam: with the increase of the density of the object, less photons will pass through it. Starting from this, we can calculate the bone mineral density in any point of the material. The radionuclide (through a sealed and shielded source of the radioisotope {sup 241}Am with an activity of 7.4 GBq and an energy of 59.6 keV) is the photons source and a scintillation detector quantify the transmitted photons through the bone to determine the density. The results obtained experimentally were compared with theoretical ones calculated by simulation with the MCNPX based Monte Carlo transport code. (author)
Institute of Scientific and Technical Information of China (English)
LI Yiwen; LI Yinghong; LU Haoyu; ZHU Tao; ZHANG Bailing; CHEN Feng; ZHAO Xiaohu
2011-01-01
This paper presents a preliminary experimental investigation on magnetohydrodynamic (MHD) power generation using seeded supersonic argon flow as working fluid.Helium and argon are used as driver and driven gas respectively in a shock tunnel.Equilibrium contact surface operating mode is used to obtain high temperature gas,and the conductivity is obtained by adding seed K2CO3 powder into the driven section.Under the conditions of nozzle inlet total pressure being 0.32 MPa,total temperature 6 504 K,magnetic field density about 0.5 T and nozzle outlet velocity 1 959 m/s,induction voltage and short-circuit current of the segmentation MHD power generation channel are measured,and the experimental results agree with theoretical calculations; the average conductivity is about 20 S/m calculated from characteristics of voltage and current.When load factor is 0.5,the maximum power density of the MHD power generation channel reaches 4.797 1 MW/m3,and the maximum enthalpy extraction rate is 0.34%.Finally,the principle and method of indirect testing for gas state parameters are derived and analyzed.
a Random Walk in Theoretical Physics
Roberts, Bruce Wharton
1995-01-01
This thesis covers four diverse topics, representing a cross section of theoretical physics (and mathematical biology). The initial two subjects deal with nonequilibrium dynamics of spatially extended systems. These two topics are spatiotemporal chaos in the complex Ginzburg-Landau equation and a mathematical model for biological evolution and mass extinctions. The study of the complex Ginzburg -Landau equation provides results on the topological defects that exist in this system. The defect-defect correlation function is calculated numerically, and the result is discussed in the context of generic scale invariance and in terms of analytic bounds. The biological evolution work provides a simple, coarse-grained description of the evolutionary process and its interaction with the physical environment. It provides testable predictions about the distribution of extinction sizes and species lifetimes found in the fossil record. The third topic covered in this thesis is real -space renormalization of the random field Ising model. The results provide evidence about the nature of the phases of the system through calculation of renormalization flows in parameter space. The calculation also gives critical exponents for the transition between phases, as well as the heights of barriers between metastable states. The final topic deals with the fractional quantum Hall effect in double quantum wells. Analytic work is done which provides a framework for calculating collective excitations within the single-mode approximation. These excitations are then calculated using Monte Carlo techniques and numerical integration. These calculations yield information about density fluctuations and excitonic modes, the latter of which can be related to tunneling spectral moments.
A novel lattice energy calculation technique for simple inorganic crystals
Energy Technology Data Exchange (ETDEWEB)
Kaya, Cemal [Department of Chemistry, Faculty of Science, Cumhuriyet University, 58140 Sivas (Turkey); Kaya, Savaş, E-mail: savaskaya@cumhuriyet.edu.tr [Department of Chemistry, Faculty of Science, Cumhuriyet University, 58140 Sivas (Turkey); Banerjee, Priyabrata [Surface Engineering and Tribology Group, CSIR-Central Mechanical Engineering Research Institute, Mahatma Gandhi Avenue, Durgapur 713209 (India)
2017-01-01
In this pure theoretical study, a hitherto unexplored equation based on Shannon radii of the ions forming that crystal and chemical hardness of any crystal to calculate the lattice energies of simple inorganic ionic crystals has been presented. To prove the credibility of this equation, the results of the equation have been compared with experimental outcome obtained from Born-Fajans-Haber- cycle which is fundamentally enthalpy-based thermochemical cycle and prevalent theoretical approaches proposed for the calculation of lattice energies of ionic compounds. The results obtained and the comparisons made have demonstrated that the new equation is more useful compared to other theoretical approaches and allows to exceptionally accurate calculation of lattice energies of inorganic ionic crystals without doing any complex calculations.
A novel lattice energy calculation technique for simple inorganic crystals
Kaya, Cemal; Kaya, Savaş; Banerjee, Priyabrata
2017-01-01
In this pure theoretical study, a hitherto unexplored equation based on Shannon radii of the ions forming that crystal and chemical hardness of any crystal to calculate the lattice energies of simple inorganic ionic crystals has been presented. To prove the credibility of this equation, the results of the equation have been compared with experimental outcome obtained from Born-Fajans-Haber- cycle which is fundamentally enthalpy-based thermochemical cycle and prevalent theoretical approaches proposed for the calculation of lattice energies of ionic compounds. The results obtained and the comparisons made have demonstrated that the new equation is more useful compared to other theoretical approaches and allows to exceptionally accurate calculation of lattice energies of inorganic ionic crystals without doing any complex calculations.
Fast Theoretical Simulation for Design of Helical Flux Compression Generators
Institute of Scientific and Technical Information of China (English)
YANG Xian-Jun; DONG Zhi-Wei
2006-01-01
A theoretical scheme is derived to achieve the numerical simulation of helical flux compression generator (HFCG) design, by which not only any physical approximation is not made, but also numerical simulation can be fast obtained. In particular, an analytic formula to calculate the inductance is deduced, which is extremely close to the experimental results. The physical process of relevant interesting physical quantity, such as inductance, enlarging current, and magnetic flux density, can be calculated to compare with the experimentally quantitative results.
Theoretical tools for atom-laser-beam propagation
Riou, Jean-Félix; Le Coq, Yann; Impens, François; Guerin, William; Bordé, Christian,; Aspect, Alain; Bouyer, Philippe
2008-01-01
We present a theoretical model for the propagation of non self-interacting atom laser beams. We start from a general propagation integral equation, and we use the same approximations as in photon optics to derive tools to calculate the atom laser beam propagation. We discuss the approximations that allow to reduce the general equation whether to a Fresnel-Kirchhoff integral calculated by using the stationary phase method, or to the eikonal. Within the paraxial approximation, we also introduce...
Caracciolo, Adriana; Vanuzzo, Gianmarco; Balucani, Nadia; Stranges, Domenico; Cavallotti, Carlo; Casavecchia, Piergiorgio
2017-09-01
We report preliminary combined experimental/theoretical results on O(3P) + 1-butene reaction dynamics with focus on atomic hydrogen displacement and molecular hydrogen elimination channels. Dynamics and relative yield of the ethylvinoxy + H and ethylketene + H2 product channels are characterized in crossed beam experiments. Stationary points and energetics of triplet/singlet C4H8O potential energy surfaces (PESs) are calculated at CCSD(T)/CBS and CASPT2 level. O(3P) attack occurs on both unsaturated C-atoms with preference for the less substituted one leading, among other products, to C2H5CHCHO + H via an exit barrier on the triplet PES, and to C2H5CHCO + H2 via a very high exit barrier on the singlet PES following intersystem crossing.
Validation and Implementation of Uncertainty Estimates of Calculated Transition Rates
Directory of Open Access Journals (Sweden)
Jörgen Ekman
2014-05-01
Full Text Available Uncertainties of calculated transition rates in LS-allowed electric dipole transitions in boron-like O IV and carbon-like Fe XXI are estimated using an approach in which differences in line strengths calculated in length and velocity gauges are utilized. Estimated uncertainties are compared and validated against several high-quality theoretical data sets in O IV, and implemented in large scale calculations in Fe XXI.