Proposed intense positron source for TESLA based on HERA-e

In this article we perform a general study of possible positron source for linear collider TESLA based on the HERA electron ring. 30 GeV electrons passing 10 T wiggler can produce intense synchrotron radiation with characteristic energy of photons of about 6 MeV. High energy photons are converted to few-MeV positrons in a suitable target. The ability of such a source to fit for the TESLA requirements is discussed. 14 refs., 3 figs

Dromion perturbation for the Davey-Stewartson-1 equations

The perturbation of the dromion of the Davey-Stewartson-1 equation is studied over the large time

Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Elucidation of the role of the complex in hydride transfer reaction between methylene blue and 1-benzyl-1,4-dihydronictinamide by effect of γ-cyclodextrin

The kinetics of the hydride transfer reaction between Methylene Blue (MB+) and&#12288;1-benzyl-1,4-dihydronicotinamide (BNAH) were studied in 10 % ethanol-90 % water mixed solvents containing &#946;- and &#947;-cyclodextrins (&#946;-CD and &#947;-CD). The pseudo-first order rate constant shows kinetic saturation at high initial concentration of BNAH. This indicates the formation of a complex between MB+ and BNAH. The reaction was suppressed by addition of &#946;-CD, but enhanced by addition of &#947;-CD. MB+ and BNAH were separately accommodated within the &#946;-CD cavity and the cavity walls may protect the activity site of the reactants. On the other hand, in the MB+-BNAH-&#947;-CD system, the inclusion of the complex between MB+ and BNAH with &#947;-CD occurred. This effect of &#947;-CD can distinguish between the productive and non-productive nature of the complex.</p

Сироватковий рівень протеїну C, фактора Bіллебранда, агрегація тромбоцитів і структурно-функціональні зміни серця ухворих на Q-інфаркт міокарда з гострою аневризмою лівого шлуночка

In 120 patients with acute Q-wave myocardial infarction levels and correlations of Protein C, Willebrand Factor, platelets aggregation and structural-functional heart indexes were investigated depending on left ventricle aneurism formation. In patients with Q-wave myocardial infarction and acute left ventricle aneurism significant enlargement of left atrium accompanied by early formation of diastolic dysfunction of II type was noted; in blood serum lower level of Protein C and increased content of Willebrand Factor were revealed. Correlation analysis revealed interrelations between indexes of platelets aggregation, coagulation hemostasis and heart remodeling in patients with Q-wave myocardial infarction and left ventricle aneurism.У 120 больных в остром периоде Q-инфаркта миокарда изучены уровень и корреляционные взаимосвязи протеина С, фактора Виллебранда, агрегации тромбоцитов и структурно-функциональных показателей сердца в зависимости от формирования аневризмы левого желудочка. У больных Q-инфарктом миокарда с острой аневризмой левого желудочка наблюдается существенное увеличение размеров левого предсердия, сопровождающиеся ранним формированием диастолической дисфункции левого желудочка II типа; в сыворотке крови определяется более низкий уровень протеина С и увеличение содержания фактора Виллебранда. Корреляционный анализ выявил взаимосвязь между показателями агрегации тромбоцитов, коагуляционного гемостаза и ремоделирования сердца у больных Q-инфарктом миокарда с аневризмой левого желудочка.У 120 хворих на гострий Q-інфаркт міокарда вивчали рівень і кореляційні зв’язки протеїну С, фактора Віллебранда, агрегації тромбоцитів і структурно-функціональних показників серця залежно від формування аневризми лівого шлуночка. У хворих на Q-інфаркт міокарда з гострою аневризмою лівого шлуночка спостерігається суттєве збільшення розміру лівого передсердя, що супроводжується раннім формуванням діастолічної дисфункції ІІ типу; в сироватці крові визначається нижчий рівень протеїну С і збільшення вмісту фактора Віллебранда. Кореляційний аналіз виявив взаємозв’язок між показниками агрегації тромбоцитів, коагуляційного гемостазу і ремоделювання серця у хворих на Q-інфаркт міокарда з аневризмою лівого шлуночка

Serum protein C, Willebrand factor, platelet aggregation and structural and functional changes of the heart in patients with Q-wave myocardial infarctoin with acute left ventricle aneurism

Abstract In 120 patients with acute Q-wave myocardial infarction levels and correlations of Protein C, Willebrand Factor, platelets aggregation and structural-functional heart indexes were investigated depending on left ventricle aneurism formation. In patients with Q-wave myocardial infarction and acute left ventricle aneurism significant enlargement of left atrium accompanied by early formation of diastolic dysfunction of II type was noted; in blood serum lower level of Protein C and increased content of Willebrand Factor were revealed. Correlation analysis revealed interrelations between indexes of platelets aggregation, coagulation hemostasis and heart remodeling in patients with Q-wave myocardial infarction and left ventricle aneurism

Sharp difference in the change in molar volumes and enthalpy of dissolution of 2D and 3D molecules in solvents illustrated by the Diels-Alder reaction

© 2020 Elsevier B.V. A sharp difference in the change in the molar volume during the transition from the solid phase to the solution for a number of 2D molecules of reagents compared with 3D molecules of the Diels-Alder reaction adducts was observed. The dissolution of 2D crystal molecules is accompanied by a significant increase in volume (10–15%) with a dissolution enthalpy close in magnitude to the fusion enthalpy. A similar transition for 3D crystal molecules is often accompanied by an unexpected decrease in volume and even negative enthalpy of dissolution in inert solvents. The similar change in these parameters is also considered for a number of 3D molecules: 1,3,5-triphenylbenzene, hexaphenylbenzene, 9,10-diphenylanthracene, congressane, and C-60 fullerene. This can be explained by the fact that the surface of large 3D molecules in a solution can be much more thoroughly surrounded by solvent molecules than in its own environment. These results indicate that the values of activation and reaction volumes and their ratio (ΔV≠S/ΔVr-n, S) may be weakly related to the mechanism of non-polar cycloaddition reactions

Diels–Alder Reaction as an Indicator of Internal and External Factors Influencing the Rate and Equilibrium: Kinetics, Thermochemistry, Catalysis, and High Pressure. A Review

Abstract: The Diels–Alder reaction (DAR), in addition to its enormous synthetic potential, is the most reliable testing ground for quantitative research of the influence of various internal and external factors on the rate and equilibrium. The influence of the energy of intermolecular orbital interaction and then the influence of the enthalpy of reaction have been considered. It has been demonstrated that the DAR rate can be described when both factors are considered jointly. Kinetic and thermochemical data for DAR in the presence of Lewis acids are discussed. New data on the DAR rate during grinding reagents in the solid phase generate many problems for further study. Finally, the analysis of extensive data on the high pressure effect on the DAR rate and equilibrium have allowed the conclusion that differences in activation volumes and reaction volumes are not related to the mechanism of the DAR

Study of all stages of the Diels–Alder reaction of cyclopentadiene with 2,3-dicyano-1,4-benzoquinone and monoadducts: Kinetics, thermochemistry, and high pressure effect

© 2020 Wiley Periodicals, Inc. The kinetic parameters and enthalpies of the Diels–Alder reactions between cyclopentadiene and 2,3-dicyano-1,4-benzoquinone leading to the formation of two different monoadducts and bisadduct were determined. The stability of adducts is compared. Monoadduct appears to be thermodynamically more stable than the bisadduct. Comparison with the other Diels–Alder reactions studied previously allows us to conclude that the heat effects upon formation of the considered Diels–Alder adducts are the lowest in comparison with all the studied dienophiles

Sharp difference in the rate of formation and stability of the Diels–Alder reaction adducts with 2,3-dicyano-1,4-benzoquinone and N-phenylimide-1,4-benzoquinone-2,3-dicarboxylic acid

This work reports new studies of the activity and Diels–Alder kinetics of a series of dienophiles: tetracyanoethylene (1), 2,3-dicyano-p-benzoquinone (10), and N-phenylimide-1,4-benzoquinone-2,3-dicarboxylic acid (11). Rate differences are interpreted in terms of the donor–acceptor properties of the reagents. The relative π-acceptor properties of the dienophiles are probed by measuring their interaction energies with a series π-donor solvents: benzene, toluene, o-xylene, and chlorobenzene. The normalized interaction energies of 1, 10, and 11 are found to be 100:64:28. Despite the increased energy of the donor–acceptor interaction, dienophile 10 is 255 times less active in the reaction with 9,10-dimethylanthracene than 11. It is suggested that this is due to the significantly lower energy of π-bond cleavage in bicyclic dienophile 11, compared with monocyclic 10