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Hu Kunming - One of the best experts on this subject based on the ideXlab platform.
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the equal probability comparison method of determining the Equivalent Electron young basis
2008Co-Authors: Hu KunmingAbstract:The concepts of the basic symmetric operator and complete symmetric operator of the Equivalent-Electron regular Young tableau T ［ λ ］ ig are presented, and the concepts of the root state and generative state generated by these symmetric operators acting on each Slater function i are also given. Based on the establishment rules of the vertical permutation operator A ［ λ ］ ig of the orthogonal normalization Young tableau T ［ λ ］ ie , the symmetric operators in A ［ λ ］ ie and the equiprobability comparison method for solving T ［ λ ］ ie are presented, which can avoid the complicated algebra involving many operators. Finally, a new method for sloving the Young basis of the Electron system with a large N is presented.
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a new young tableau method of obtaining Equivalent Electron young basis
2007Co-Authors: Hu Kunming, Wang JianboAbstract:In this paper, the projection function of regular Young tableau of Equivalent-Electrons is proved to be a Slauer function, and the operation rules of Young's permutation operators operating on the Slater function are given. The Young operators can be distinguished as elimination operator and effective permutation operator by the normalization of Young basis, then the constructive rules of permutation operators of the orthogonal normalization of Young basis is given. By this method, the number of Young's permutation operators is reduced and the new Young tableau method of obtaining Equivalent-Electron Young basis is represented.
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discussion on the transformation property between the configuration wavefunction of the Equivalent Electron and the young tableau
2005Co-Authors: Hu KunmingAbstract:The transformation property between the configuration wavefunction of the Equivalent-Electron and the Young tableau is pointed out to be unitary but not to be Hermite unitary. And a sign error of the spectrum item wavefunction is presented.
Walker Adrian - One of the best experts on this subject based on the ideXlab platform.
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Development of an anatomically correct mouse phantom for dosimetry measurement in small animal radiotherapy research
2019Co-Authors: Soultanidish George, Subiel Anna, Renard Isaline, Reinhart, Anna Merle, Green, Victoria L, Oelfke Uwe, Archibald, Stephen J, Greenman John, Tulk Amanda, Walker AdrianAbstract:Significant improvements in radiotherapy are likely to come from biological rather than technical optimization, for example increasing tumour radiosensitivity via combination with targeted therapies. Such paradigms must first be evaluated in preclinical models for efficacy, and recent advances in small animal radiotherapy research platforms allow advanced irradiation protocols, similar to those used clinically, to be carried out in orthotopic models. Dose assessment in such systems is complex however, and a lack of established tools and methodologies for traceable and accurate dosimetry is currently limiting the capabilities of such platforms and slowing the clinical uptake of new approaches. Here we report the creation of an anatomically correct phantom, fabricated from materials with tissue-Equivalent Electron density, into which dosimetry detectors can be incorporated for measurement as part of quality control (QC). The phantom also allows training in preclinical radiotherapy planning and cross-institution validation of dose delivery protocols for small animal radiotherapy platforms without the need to sacrifice animals, with high reproducibility. Mouse CT data was acquired and segmented into soft tissue, bone and lung. The skeleton was fabricated using 3D printing, whilst lung was created using computer numerical control (CNC) milling. Skeleton and lung were then set into a surface-rendered mould and soft tissue material added to create a whole-body phantom. Materials for fabrication were characterized for atomic composition and attenuation for x-ray energies typically found in small animal irradiators. Finally cores were CNC milled to allow intracranial incorporation of bespoke detectors (alanine pellets) for dosimetry measurement.status: publishe
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Development of an anatomically correct mouse phantom for dosimetry measurement in small animal radiotherapy research
2019Co-Authors: Soultanidis George, Subiel Anna, Renard Isaline, Reinhart, Anna Merle, Green, Victoria L, Oelfke Uwe, Archibald, Stephen J, Greenman John, Tulk Amanda, Walker AdrianAbstract:Significant improvements in radiotherapy are likely to come from biological rather than technical optimization, for example increasing tumour radiosensitivity via combination with targeted therapies. Such paradigms must first be evaluated in preclinical models for efficacy, and recent advances in small animal radiotherapy research platforms allow advanced irradiation protocols, similar to those used clinically, to be carried out in orthotopic models. Dose assessment in such systems is complex however, and a lack of established tools and methodologies for traceable and accurate dosimetry is currently limiting the capabilities of such platforms and slowing the clinical uptake of new approaches. Here we report the creation of an anatomically correct phantom, fabricated from materials with tissue-Equivalent Electron density, into which dosimetry detectors can be incorporated for measurement as part of quality control (QC). The phantom also allows training in preclinical radiotherapy planning and cross-institution validation of dose delivery protocols for small animal radiotherapy platforms without the need to sacrifice animals, with high reproducibility. Mouse CT data was acquired and segmented into soft tissue, bone and lung. The skeleton was fabricated using 3D printing, whilst lung was created using computer numerical control (CNC) milling. Skeleton and lung were then set into a surface-rendered mould and soft tissue material added to create a whole-body phantom. Materials for fabrication were characterized for atomic composition and attenuation for x-ray energies typically found in small animal irradiators. Finally cores were CNC milled to allow intracranial incorporation of bespoke detectors (alanine pellets) for dosimetry measurement.
Don H Madison - One of the best experts on this subject based on the ideXlab platform.
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differential cross sections for the ionization of oriented h2 molecules by Electron impact
2008Co-Authors: J Colgan, Michael S Pindzola, F Robicheaux, Christian Kaiser, Andrew James Murray, Don H MadisonAbstract:A nonperturbative close-coupling technique is used to calculate differential cross sections for the Electron-impact ionization of H2 at an energy of 35.4 eV. Our approach allows cross sections for any orientation of the molecule with respect to the incident Electron beam to be analyzed. New features in the resulting cross sections are found compared with the case where the molecular orientation is averaged, and also with cross sections for He at Equivalent Electron kinematics. When averaged over all possible molecular orientations, good agreement is found with recent experimental results. DOI: 10.1103/PhysRevLett.101.233201 PACS numbers: 34.80.Dp Studies of the Electron-impact ionization of small atoms and molecules continues to be the source of new discoveries as to the role of Electron correlation in the break-up process, leading to new ways ofinvestigating the Electronic structure of the target. Measures of cross sections which are differential in both the energies and angles of the outgoing Electrons [commonly known as triple differential cross sections (TDCS)] provide the most detailed information about the interaction between the outgoing Electrons. For simple atoms, good agreement now exists, for the most part, between experiment and several theoretical approaches for differential cross sections for the Electronimpact ionization of H [1–4] and He [5–7]. For molecules, the problem is considerably more complex. The nonspherical nature of the target, along with the extra vibrational and rotational degrees offreedom inherent in even a simple diatomic molecule, make the theoretical description much more challenging. Consequently, most theoretical approaches to date have focused on ionization by high incident energy Electrons where plane-wave impulse approximations may be employed, and where severe approximations, such as ignoring exchange effects [8], may be used. Another recent theoretical technique [9–11] which uses the three-body distorted-wave (3DW) approach (where distorted-waves are used to describe all incident and outgoing Electrons) previously successfully used for atoms, also makes an orientation-average approximation, in which the molecular wave function used is averaged over all molecular orientations. This approach finds remarkably good agreement with experiment for most ge
U S Inan - One of the best experts on this subject based on the ideXlab platform.
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nighttime d region Electron density measurements from elf vlf tweek radio atmospherics recorded at low latitudes
2012Co-Authors: Ajeet K Maurya, Sushil Kumar, B Veenadhari, Rajesh Singh, M B Cohen, R Selvakumaran, Sneha A Gokani, P Pant, A K Singh, U S InanAbstract:[1] Dispersive atmospherics (tweeks) observed during 2010 simultaneously at two low-latitude stations, Allahabad (geomagnetic latitude, 16.05°N) and Nainital (geomagnetic latitude, 20.48°N), have been used to estimate the nighttime D region Electron density at the ionospheric reflection height under the local nighttime propagation (21:00–02:00 LT or 15:30–20:30 UT). The analysis of simultaneously recorded tweeks at both the stations on five international quiet days during one month each from summer (June), winter (January), and equinox (March) seasons shows that the D region Electron density varies 21.5–24.5 cm−3 over the ionospheric reflection height of 85–95 km. The average values of Wait lower ionospheric parameters: ionospheric reference height h′ and sharpness factor β are almost same during winter (85.9–86.1 km, 0.51–0.52 km−1) and equinox (85.6–85.7 km, 0.54 km−1) seasons. The values of h′ and β during summer season are about 83.5 km and 0.60 km−1at both stations. Overall, Equivalent Electron density profile obtained using tweek method shows lower values of Electron density by about 5–60% than those obtained using the International Reference Ionosphere (IRI-2007) model and lower/higher by 2–68% than those obtained using rocket technique. The Electron density estimated using all three techniques (tweek, IRI-2007, and rocket) is consistent in the altitude range of 82–98 km. The estimated geographic locations of causative lightnings of tweeks were matched with the locations and times of lightnings detected by the World-Wide Lightning Location Network (WWLLN). The WWLLN detected about 27.5% of causative lightnings of tweeks simultaneously observed at both the stations.
Sushil Kumar - One of the best experts on this subject based on the ideXlab platform.
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nighttime d region Electron density measurements from elf vlf tweek radio atmospherics recorded at low latitudes
2012Co-Authors: Ajeet K Maurya, Sushil Kumar, B Veenadhari, Rajesh Singh, M B Cohen, R Selvakumaran, Sneha A Gokani, P Pant, A K Singh, U S InanAbstract:[1] Dispersive atmospherics (tweeks) observed during 2010 simultaneously at two low-latitude stations, Allahabad (geomagnetic latitude, 16.05°N) and Nainital (geomagnetic latitude, 20.48°N), have been used to estimate the nighttime D region Electron density at the ionospheric reflection height under the local nighttime propagation (21:00–02:00 LT or 15:30–20:30 UT). The analysis of simultaneously recorded tweeks at both the stations on five international quiet days during one month each from summer (June), winter (January), and equinox (March) seasons shows that the D region Electron density varies 21.5–24.5 cm−3 over the ionospheric reflection height of 85–95 km. The average values of Wait lower ionospheric parameters: ionospheric reference height h′ and sharpness factor β are almost same during winter (85.9–86.1 km, 0.51–0.52 km−1) and equinox (85.6–85.7 km, 0.54 km−1) seasons. The values of h′ and β during summer season are about 83.5 km and 0.60 km−1at both stations. Overall, Equivalent Electron density profile obtained using tweek method shows lower values of Electron density by about 5–60% than those obtained using the International Reference Ionosphere (IRI-2007) model and lower/higher by 2–68% than those obtained using rocket technique. The Electron density estimated using all three techniques (tweek, IRI-2007, and rocket) is consistent in the altitude range of 82–98 km. The estimated geographic locations of causative lightnings of tweeks were matched with the locations and times of lightnings detected by the World-Wide Lightning Location Network (WWLLN). The WWLLN detected about 27.5% of causative lightnings of tweeks simultaneously observed at both the stations.
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nighttime d region Equivalent Electron density determined from tweek sferics observed in the south pacific region
2009Co-Authors: Sushil Kumar, Anil Deo, Visagaperuman RamachandranAbstract:Atmospherics or sferics that originate from lightning discharges on propagating large distances in the Earthionosphere waveguide, particularly at the night, form dispersed sferics called tweeks. Tweeks are novel diagnostic tool to monitor the nighttime D-region ionosphere. Mean Equivalent Electron density nem at mean tweek reflection heights hm and Electron density profile have been estimated using the higher harmonic tweeks recorded in the time between 21–03 hrs LT at Suva (18.2°S, 178.3°E), Fiji, during a period March–December 2006. The values of nem vary from 29–170 cm−3 in the altitude range of about 3.5 km at hm of about 83 km. In terms of usually used exponential Electron density profile, the ionospheric reference height and the exponential sharpness factor are calculated to be 83.1 km and 0.64 km−1, respectively. The scale height is calculated to be 1.9 km. Equivalent Electron density profile of the nighttime lower ionosphere, using tweek method, shows lower values of Electron density by about 20–45% than those obtained from the IRI-2001 model.