2,183 research outputs found

    Singular Schrodinger operators in one dimension

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    We consider a class of singular Schr\"odinger operators HH that act in L2(0,)L^2(0,\infty), each of which is constructed from a positive function ϕ\phi on (0,)(0,\infty). Our analysis is direct and elementary. In particular it does not mention the potential directly or make any assumptions about the magnitudes of the first derivatives or the existence of second derivatives of ϕ\phi. For a large class of HH that have discrete spectrum, we prove that the eigenvalue asymptotics of HH does not depend on rapid oscillations of ϕ\phi or of the potential. Similar comments apply to our treatment of the existence and completeness of the wave operators.Comment: 23 page

    Study of High Energy Gamma-Quanta Beyond the Atmosphere

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    Measurements of primary cosmic radiation gamma quanta from Proton I and II satellite

    Nonlinear interfaces: intrinsically nonparaxial regimes and effects

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    The behaviour of optical solitons at planar nonlinear boundaries is a problem rich in intrinsically nonparaxial regimes that cannot be fully addressed by theories based on the nonlinear Schrödinger equation. For instance, large propagation angles are typically involved in external refraction at interfaces. Using a recently proposed generalized Snell's law for Helmholtz solitons, we analyse two such effects: nonlinear external refraction and total internal reflection at interfaces where internal and external refraction, respectively, would be found in the absence of nonlinearity. The solutions obtained from the full numerical integration of the nonlinear Helmholtz equation show excellent agreement with the theoretical predictions

    Study of the nuclear component of primary cosmic rays aboard AES ''Proton-2''

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    Nuclear component of primary cosmic rays aboard Proton II satellite studied with aid of Cherenkov spectromete

    Quasigroups, Asymptotic Symmetries and Conservation Laws in General Relativity

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    A new quasigroup approach to conservation laws in general relativity is applied to study asymptotically flat at future null infinity spacetime. The infinite-parametric Newman-Unti group of asymptotic symmetries is reduced to the Poincar\'e quasigroup and the Noether charge associated with any element of the Poincar\'e quasialgebra is defined. The integral conserved quantities of energy-momentum and angular momentum are linear on generators of Poincar\'e quasigroup, free of the supertranslation ambiguity, posess the flux and identically equal to zero in Minkowski spacetime.Comment: RevTeX4, 5 page

    Structural and Functional Organization of Photosynthetic Apparatus in Wild Halophites

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    The structural and molecular parameters of photosynthetic apparatus in plants with different strategies for the accumulation of salts were investigated. The objects of the study were euhalophytes (Salicornia perennans, Suaeda salsa, Halocnemum strobilaceum), a crynohalophyte (Limonium gmelinii) and a glycohalophyte (Artemisia santonica). The euhalophytes S. perennans and S. salsa belong to plants of the halosucculent type, while the other three species represent the xerophilic type. Larger cells with a great number of chloroplasts, a high content of membrane glycerolipids and unsaturated C18:3 fatty acid and smaller pigment and light-harvesting complexes characterize the features of euhalophytes with a succulent leaf type. Therefore, thefeatures of the halophyte photosynthetic apparatus structure are closely related to its functional indicators and are defined by a strategy in both the accumulation of salts and the method of water regime regulation. Keywords: chlorophyll, lipids and fatty acids, photosynthetic apparatus, ultrastructure of chloroplast

    Establishment and Development of Ningxia Hui Autonomous Region of People’s Republic of China (1949—1979)

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    The article is devoted to one of the autonomous regions of the People’s Republic of China — the Ningxia Hui Autonomous Region (NHAR). The historical events associated with the territory of modern NHAR, the features of the development of Islam in China and the formation of the Hui ethnic group is showed in the article. As a result of the study, it was revealed that the creation of the NHAR was due to the ideological concepts of national development laid down in the 1954 Constitution of the People's Republic of China. Based on documents published in China in Chinese, it is proved that the creation of the NHAR played a significant role in the ethnic development of the Hui people. It was revealed that the political changes that took place in the PRC in 1958-1976 and associated with the policy of the “Three Red Banners” and the “Great Proletarian Cultural Revolution” caused significant damage both to the economy of the NHAR and to ethnic stability in the considered region of China. The implementation of political campaigns of this period even led to clashes on confessional and ethnic grounds, which required the use of armed force to suppress them. As a result of the study, it was revealed that the situation in the NHAR began to stabilize and change only after the death of Mao Zedong and the beginning of Deng Xiaoping's reforms in 1979

    Complex 99mTc-PDA-DTPA for myocardial imaging

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    The 123I-labeled fatty acids such as 123I-Iodophenylpentadecanoic acid and 123I-Beta-methyliodophenylpentadecanoic acid are the agents used clinically for myocardial imaging. Fatty acids are the major source of energy for the normal myocardium. However, under ischemic conditions the myocardial cells switch to glucose metabolism for their energy needs. Fatty acids undergo prolonged metabolic stunning in patients with reversible ischemia, thereby helping in early diagnosis of coronary artery disease in highrisk patients. High cost andlimited availability of cyclotron-produced 123I, makes 99mTc-labeled fatty acids more desirable for the purpose. In diagnosis the dominant radionuclide is 99mTc. It is estimated that it is involved in about 85% of all imaging procedures in nuclear medicine. The method for preparation of new 99mTc-fatty chemical systems based on modified diethylene triamine pentaacetic acid (DTPA) molecule has been elaborated in this work . The main advantage using DTPA as chelate agent for radioactive label, is the molecule or it's derivative ability to form sufficiently stable complexes with different radioactive metals including technetium-99. Moiety of pentadecanoic acid addition gave the ability to prepare modified complex of DTPA. In a labeling procedure, freshly eluted Na99mTcO4 (20mCi) was added to a mixture of cysteine, stannous chloride, PDK-DTPA and ethanol in a vial. On keeping the reaction mixture at 90 0C for 30 min, [99mTc-PDK-DTPA] radiopharmaceutical was formed. Thereafter, the reaction mixture was cooled over ice and characterized by HPLC. The result of dynamic scintigraphic research showed, that after being injected, the substance is actively acumulated into myocardium. Eventually one can say that modified DTPA-moleculs are functionally suitable for myocardial imaging
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