Contractions of Low-Dimensional Lie Algebras

Theoretical background of continuous contractions of finite-dimensional Lie algebras is rigorously formulated and developed. In particular, known necessary criteria of contractions are collected and new criteria are proposed. A number of requisite invariant and semi-invariant quantities are calculated for wide classes of Lie algebras including all low-dimensional Lie algebras. An algorithm that allows one to handle one-parametric contractions is presented and applied to low-dimensional Lie algebras. As a result, all one-parametric continuous contractions for the both complex and real Lie algebras of dimensions not greater than four are constructed with intensive usage of necessary criteria of contractions and with studying correspondence between real and complex cases. Levels and co-levels of low-dimensional Lie algebras are discussed in detail. Properties of multi-parametric and repeated contractions are also investigated.Comment: 47 pages, 4 figures, revised versio

Equivalence principle and experimental tests of gravitational spin effects

We study the possibility of experimental testing the manifestations of equivalence principle in spin-gravity interactions. We reconsider the earlier experimental data and get the first experimental bound on anomalous gravitomagnetic moment. The spin coupling to the Earth's rotation may also be explored at the extensions of neutron EDM and g-2 experiments. The spin coupling to the terrestrial gravity produces a considerable effect which may be discovered at the planned deuteron EDM experiment. The Earth's rotation should also be taken into account in optical experiments on a search for axionlike particles.Comment: 12 pages, version to appear in Physical Review

Magneto-Gyrotropic Photogalvanic Effects in Semiconductor Quantum Wells

We show that free-carrier (Drude) absorption of both polarized and unpolarized terahertz radiation in quantum well (QW) structures causes an electric photocurrent in the presence of an in-plane magnetic field. Experimental and theoretical analysis evidences that the observed photocurrents are spin-dependent and related to the gyrotropy of the QWs. Microscopic models for the photogalvanic effects in QWs based on asymmetry of photoexcitation and relaxation processes are proposed. In most of the investigated structures the observed magneto-induced photocurrents are caused by spin-dependent relaxation of non-equilibrium carriers

Каталитическая дезоксигенация воды на волокнистых ионитах, модифицированных гидроксидами железа и марганца

Catalysts based on iron and manganese hydroxide modified fibrous ion exchangers FIBAN K-4 and FIBAN X-1 have been synthesized and tested for hydrogenation of oxygen dissolved in water. It has been found that polyampholyte FIBAN X-1 samples containing ferric hydroxide are the most active in water deoxygenation: the residual oxygen content under the best process conditions does not exceed 20 g/1, which corresponds to the industry standards. It has been shown that the formation of iron - amino group nitrogen complex in the ion exchanger matrix occurs due to introduction of Fe3+ cations in FIBAN X-1 (pH 2-2.2). It has also been shown that iron and manganese hydroxide modified FIBAN X-1 is a highly active catalyst for H2O2 decomposition.На основе волокнистых ионитов ФИБАН К-4 и ФИБАН Х-1, модифицированных гидроксидами железа и марганца, синтезированы катализаторы и испытаны в реакции гидрирования растворенного в воде кислорода. Установлено, что наиболее активными в процессе дезоксигенации воды являются образцы полиамфолита ФИБАН Х-1, содержащие гидроксид железа в качестве активного компонента: остаточное содержание кислорода в воде в оптимальных условиях процесса не превышает 20 мкг/л, что соответствует отраслевому нормативу объектов теплоэнергетики по данному показателю. Показано, что при ионообменном введении катионов Fe3+ в ФИБАН Х-1 (рН 2-2,2) происходит образование комплексов железа с участием азота аминогрупп матрицы ионита. ФИБАН Х-1, модифицированный гидроксидами железа и марганца, обладает высокой каталитической активностью в разложении Н2О2

Катализатор восстановления оксида азота оксидом углерода

The catalyst for NO reduction by carbon monoxide containing copper chromite, chromium, copper and iron oxides on y-Al2O3, has been developed. NO conversion over the catalyst in the reaction mixture containing 10 vol.% of oxygen is up to 83 % (200 °C, 12 000 h-1). Carbon monoxide oxidation proceeds at the expense of catalyst lattice oxygen, and the resultant reduced sites are oxidized by nitrous oxide or oxygen from gaseous phase.Разработан катализатор восстановления NO оксидом углерода, содержащий хромит меди, оксиды хрома, меди и железа на y-Al2O3. Конверсия NO в его присутствии достигает ~83 % при 10 об.% кислорода в газовой смеси (200оС, 12000 ч-1). Окисление СО идет за счет решеточного кислорода катализатора, а образующиеся восстановленные центры катализатора окисляются оксидом азота или газообразным кислородом

"Pair" Fermi contour and repulsion-induced superconductivity in cuprates

The pairing of charge carriers with large pair momentum is considered in connection with high-temperature superconductivity of cuprate compounds. The possibility of pairing arises due to some essential features of quasi-two-dimensional electronic structure of cuprates: (i) The Fermi contour with strong nesting features; (ii) The presence of extended saddle point near the Fermi level; (iii) The existence of some ordered state (for example, antiferromagnetic) close to the superconducting one as a reason for an appearing of "pair" Fermi contour resulting from carrier redistribution in momentum space. In an extended vicinity of the saddle point, momentum space has hyperbolic (pseudoeuclidean) metrics, therefore, the principal values of two-dimensional reciprocal reduced effective mass tensor have unlike signs. Rearrangement of holes in momentum space results in a rise of "pair" Fermi contour which may be defined as zero-energy line for relative motion of the pair. The superconducting gap arises just on this line. Pair Fermi contour formation inside the region of momentum space with hyperbolic metrics results in not only superconducting pairing but in a rise of quasi-stationary state in the relative motion of the pair. Such a state has rather small decay and may be related to the pseudogap regime of underdoped cuprates. It is concluded that the pairing in cuprates may be due to screened Coulomb repulsion. In this case, the superconducting energy gap in hole-doped cuprates exists in the region of hole concentration which is bounded both above and below. The superconducting state with positive condensation energy exists in more narrow range of doping level inside this region. Such hole concentration dependence correlates with typical phase diagram of cuprates.Comment: 23 pages, 11 figures. Submitted to Phys. Rev.

Коморбидность ахалазии пищевода, смешанной тревожной и депрессивной реакции у пациентки молодого возраста: проблемы диагностики и лечения

Achalasia cardia (“cardiospasm”, “phrenospasm”, “dolichoesophagus”, “megaesophagus”, “stenosis of cardia”) represents a primary impairment of esophageal motor function associated with impaired lower esophageal sphincter relaxation and peristalsis defects of the thoracic esophagus. It is diagnosed at the age of 25 to 60 years, making up to 20% of all diseases of the esophagus, and is characterized by a triad of symptoms: dysphagia, regurgitation and chest pain when swallowing. In most cases the first manifestations of achalasia are preceded by stress situations in the anamnesis that complicates the differential diagnosis of psychogenic esophageal spasm. The presented clinical case illustrates difficulties of early diagnosis of achalasia cardia in a young femalepatient with severe anxiety and depressive symptoms which develop under conditions of chronic stressful situations in the family or at work. The issues of interdisciplinary interaction of health professionals (physician, gastroenterologist, psychiatrist, psychotherapist, and surgeon) on the course of examination and management of patients with comorbid physical and mental pathology are discussed. The efficiency of the integrative approach to treatment and rehabilitation with the use of modern reconstructive surgical interventions as well as conservative methods of therapy, psychopharmacotherapy and personality-oriented psychotherapy proves the relevance of studying psychosomatic aspects of achalasia cardia.Ахалазия кардии (кардиоспазм, френоспазм, долихоэзофагус, мегаэзофагус, кардиостеноз) представляет собой первичное нарушение двигательной функции пищевода, связанное с ухудшением расслабления нижнего пищеводного сфинктера и дефектами перистальтики его грудного отдела. Диагностируется в возрасте 25–60 лет, составляя до 20% случаев всех заболеваний пищевода, характеризуется триадой симптомов: дисфагией, регургитацией, загрудинными болями при глотании. В большинстве случаев первым проявлениям ахалазии предшествуют стрессовые ситуации в анамнезе, что затрудняет дифференциальную диагностику с психогенным эзофагоспазмом. Представленный клинический случай иллюстрирует трудности диагностики ахалазии кардиального отдела пищевода у женщины молодого возраста с выраженной тревожной и депрессивной симптоматикой, развившейся в условиях хронической стрессовой ситуации семейного и производственного плана. Обсуждаются вопросы междисциплинарного взаимодействия специалистов (терапевта, гастроэнтеролога, психиатра, психотерапевта, хирурга) по тактике обследования и ведения больной с коморбидной соматической и психической патологией. Эффективность интегративного подхода к лечению и реабилитации с использованием современных реконструктивных хирургических вмешательств, а также консервативных методов терапии, психофармакотерапии, личностно ориентированной психотерапии свидетельствует об актуальности изучения психосоматических аспектов ахалазии кардии

Comorbidity of esophageal achalasia, mixed anxiety and depressive reaction in a young female patient: problems of diagnosis and treatment

Achalasia cardia (“cardiospasm”, “phrenospasm”, “dolichoesophagus”, “megaesophagus”, “stenosis of cardia”) represents a primary impairment of esophageal motor function associated with impaired lower esophageal sphincter relaxation and peristalsis defects of the thoracic esophagus. It is diagnosed at the age of 25 to 60 years, making up to 20% of all diseases of the esophagus, and is characterized by a triad of symptoms: dysphagia, regurgitation and chest pain when swallowing. In most cases the first manifestations of achalasia are preceded by stress situations in the anamnesis that complicates the differential diagnosis of psychogenic esophageal spasm. The presented clinical case illustrates difficulties of early diagnosis of achalasia cardia in a young femalepatient with severe anxiety and depressive symptoms which develop under conditions of chronic stressful situations in the family or at work. The issues of interdisciplinary interaction of health professionals (physician, gastroenterologist, psychiatrist, psychotherapist, and surgeon) on the course of examination and management of patients with comorbid physical and mental pathology are discussed. The efficiency of the integrative approach to treatment and rehabilitation with the use of modern reconstructive surgical interventions as well as conservative methods of therapy, psychopharmacotherapy and personality-oriented psychotherapy proves the relevance of studying psychosomatic aspects of achalasia cardia