Locus configurations and ∨\vee-systems

We present a new family of the locus configurations which is not related to $\vee$-systems thus giving the answer to one of the questions raised in \cite{V1} about the relation between the generalised quantum Calogero-Moser systems and special solutions of the generalised WDVV equations. As a by-product we have new examples of the hyperbolic equations satisfying the Huygens' principle in the narrow Hadamard's sense. Another result is new multiparameter families of $\vee$-systems which gives new solutions of the generalised WDVV equation.Comment: 12 page

Piezoelectric effect in p -Si/SiGe/(001)Si modulation doped heterostructures

We present the results of calculations of the piezoelectric effect in a Si/SiGe multilayer structure with a narrow quantum well and a wide layer of doped Si semiconductor. The proposed theory is a possible explanation of some recent experiments on these structures.Представлені результати розрахунків п’єзоелектричного ефекту в Si/SiGe багатошаровій структурі з вузькою квантовою ямою і товстим шаром легованого напівпровідного кремнію Si. Запропонована теорія є можливим поясненням деяких недавніх екпериментів на цих структурах

A highly emissive inorganic hexamolybdenum cluster complex as a handy precursor for the preparation of new luminescent materials

The synthesis and characterisation of a new, highly luminescent inorganic cluster complex, (Bu4N)2[Mo6I 8(NO3)6], are described. The complex possesses labile nitrato ligands and is therefore a useful precursor for the design of new luminescent materials. To exemplify this, functionalised polystyrene beads have been utilised as "polymeric ligands" to immobilise the molybdenum cluster complex. This journal i

Magnetotransport studies of SiGe-based p-type heterostructures: problems of the effective mass determination

The Shubnikov–de Haas oscillations method of the effective mass extraction was illustrated by the magnetotransport properties investigation of two-dimensional hole gas in Si₁₋xGex (x = 0.13, 0.36, 0.95, 0.98) QWs. We have found that for certain samples our data cannot be fitted to standard theoretical curves in which the scattering of charge carriers is described by conventional Dingle factor. It is demonstrated that reasons of deviations of the experiment from the theory are as follows; (i) influence of the spin splitting on amplitude of SdH oscillations maxima; (ii) extra broadening of the Landau levels attributed to existence of inhomogeneous distribution of the carrier concentration; (iii) the influence of the concurrent existence of short and long-range scattering potentials; (iv) the population of second energy level in the quantum well. The ways to calculate the effective masses m* of holes in all cases are presented and values of m* are found for studied heterostructures

Temperature dependence of the breakdown of the quantum Hall effect studied by induced currents

Copyright © 2004 The American Physical SocietyWe have developed a model of the high-current breakdown of the integer quantum Hall effect, as measured in contactless experiments using a highly-sensitive torsion balance magnetometer. The model predicts that, for empirically “low-mobility” samples (μ<75 m2 V−1 s−1), the critical current for breakdown should decrease with, and have a linear dependence on, temperature. This prediction is verified experimentally with the addition of a low-temperature saturation of the critical current at a temperature that depends on both sample number density and filling factor. It is shown that this saturation is consistent with quasielastic inter-Landau-level scattering when the maximum electric field in the sample reaches a large enough value. In addition we show how this model can be extended to give qualitative agreement with experiments on high-mobility samples

ТОПОГРАФО-АНАТОМИЧЕСКАЯ ХАРАКТЕРИСТИКА АНТЕРОЛАТЕРАЛЬНОЙ СВЯЗКИ КОЛЕННОГО СУСТАВА

Background: anterolateral ligament (ALL) is known since it was found in 1879 by Paul Segond. During more than 130 years this anatomical structure was not popular, later it became especially relevant, when its involvement in knee joint rotational stability was demonstrated by different studies. However, data about anterolateral ligament in the knee joint is controversial and limited so further research is necessary.Purpose of the study: to investigate frequency of occurrence, severity and features of topography of anterolateral ligament of the knee joint in the context of stabilizing procedures on the knee joint.Materials and methods: the study included 60 samples of lower limbs obtained from 30 unfixed corpses of people who died at the age from 69 to 99 years. Topography-anatomical study was performed with knee bent at 90° with internal rotation of lower leg using basic surgical instruments set and precision preparation instruments set. When the ligament was identified, relationship with the lateral meniscus body was evaluated, relationship with peroneal collateral ligament (mainly by connective fibers) and the presence of lateral lower knee vessels (artery and veins) were evaluated. Also, the place of ligament attachment on lateral epicondyle of femur and lateral condyle of tibia were measured.Results: the incidence of ALL in studied age group is 56.6 percent. ALL was observed in both knee joints in 100% of cases. In women ALL was observed in 66.7% (24 joints out of 36), in men — 41.6% (10 joint out of 24). The average length of the ALL was 38.5±4.4 mm. The average width at the level of joint gap — 4.45±0.85 mm.The location of the attachment to the lateral epicondyle of the femur was represented in three anatomical variants: posterior and proximal to the lateral collateral ligament — 64.7%, anterior to the lateral collateral ligament — 23.5%, in the place of attachment of popliteal muscle tendon or next to it — 11.8%. The place of attachment on lateral condyle of the tibia is typical — approximately in the middle of the line from fibula head to Gerdy tubercle.Conclusion. Based on the authors’ findings and findings of foreign studies the optimal area for proximal channel formation is the posterior position and proximal to place of lateral collateral ligament beginning. Also, the anatomical regularity of lateral lower knee vessels is obtained, that allows to preserve one of the main blood supply sources of anterolateral area of the knee joint.Цель исследования — оценить частоту встречаемости, выраженность и особенности топографии антеролатеральной связки (АЛС) коленного сустава применительно к стабилизирующим операциям на коленном суставе.Материал и методы. В исследование были включены 60 препаратов нижних конечностей, полученных от 30 нефиксированных трупов людей, умерших в возрасте от 69 до 99 лет. Было выполнено препарирование обычным способом 30 парных коленных суставов. При обнаружении АЛС производилась оценка отношений АЛС с телом латерального мениска и ее связь с малоберцовой коллатеральной связкой, оценивалось наличие латеральных нижних коленных сосудов (артерия и вены), а также место прикрепления АЛС на латеральном надмыщелке бедренной кости и место прикрепления на латеральном мыщелке большеберцовой кости. Также измерялись длина связки, ширина в месте прикрепления АЛС на латеральном надмыщелке бедренной кости, ширина на уровне суставной щели и ширина в месте прикрепления АЛС на латеральном мыщелке большеберцовой кости.Результаты. Частота встречаемости антеролатеральной связки в изучаемой возрастной группе составила 56,6%, причем во всех наблюдениях она присутствовала в обоих коленных суставах. У женщин связка была обнаружена в 66,7% наблюдений (24 сустава из 36), у мужчин — в 41,6% (10 суставов из 24). Средняя длина связки — 38,5±4,4 мм, средняя ширина на уровне суставной щели — 4,45±0,85 мм. Место крепления на латеральном надмыщелке бедренной кости представлено в трех вариантах: кзади и проксимальнее от малоберцовой коллатеральной связки — 64,7%; кпереди от малоберцовой коллатеральной связки — 23,5%; в месте крепления сухожилия подколенной мышцы или рядом с ним — 11,8%. Место крепления на латеральном мы- щелке большеберцовой кости достаточно стандартно — приблизительно на середине линии, проведенной от головки малоберцовой кости к бугорку Gerdy.Заключение. Оптимальной областью для формирования проксимального канала при хирургическом восстановлении АЛС является расположение кзади и проксимальнее места начала малоберцовой коллатеральной связки. Выявленная закономерность хода латеральных нижних коленных сосудов позволит сохранить один из основных источников кровоснабжения переднелатеральной области коленного сустава

Germanium quantum well with two subbands occupied: kinetic properties

Multisubband transport of the p-type Si₀.₄Ge₀.₆/Ge/Si₀.₄Ge₀.₆ heterostructure has been investigated by means of magnetotransport measurements at low temperatures and high magnetic fields. Two frequency Shubnikov–de Haas oscillations indicate occupation of two subbands. This allows us to determine the densities and mobilities of the charge carriers on each subband. Shubnikov–de Haas oscillations reveal two 2D conduction subbands with carrier effective masses of 0.112m₀ and 0.131m₀. The quantum Hall ferromagnetic states which results from the crossing of two Landau levels with opposite spin and different subband was observed in SiGe systems for the first time

Stevioside Has the Maximum Biological Activity among Natural Stevia Diterpenes

© 2020, Pleiades Publishing, Ltd. Abstract: The concentrations of steviol and its derivatives stimulating the growth of wheat plants were measured: 10–8 for stevioside and 10–9 М for steviol and isosteviol. It was found that stevioside increased the activity of amylolytic enzymes and protein content, as well as frost tolerance of the roots of wheat seedlings. Thus, stevioside can be recommended for the development of complex phytopreparations for stimulating the growth processes and increasing the resistance of wheat plants to low temperatures

Phonon-drag thermopower in Si:B and Si:Sb ?-doped samples

The thermal conductivity and the thermoelectric power of two dimensional hole and electron gases in B and Sb delta-doped Si structures have been measured for the first time. The temperature range was 1.4 K to 30 K, and carrier sheet densities were in the range 0.3 to 1.0 × 1014 cm-2. Kohn anomalies have been observed in all samples. The thermopower is dominated by the phonon drag contribution in each case. Calculations of the temperature dependence of the thermopower agree with experimental data when unscreened phonon scattering potentials are used for Si:B and Si:Sb

The overheating effects in germanium quantum well with two subbands occupied

The charge carrier overheating effect was studied in the p-type Si₀.₄Ge₀.₆/Ge/Si₀.₄Ge₀.₆ heterostructure with two subband occupy. The temperature dependences of hole-phonon relaxation time τh-ph at weak magnetic fields demonstrated transition of the 2D system from regime of “partial inelasticity” characterized by dependence τ⁻¹h-ph ∝ T² to regime of small-angle scattering, described by dependence τ-1h-ph ∝ T⁵ with temperature increase. But in higher magnetic fields the dependence τ⁻¹h-ph ∝ T³ manifests itself on dependences τh-ph(Th-ph). The possible explanations of such dependences are discussed.Ефект перегріву носіїв заряду вивчався в гетероструктурі Si₀.₄Ge₀.₆/Ge/Si₀.₄Ge₀.₆ p-типу з двома зайнятими підзонами. В слабких магнітних полях температурні залежності часу дірково-фононної релаксації h-ph τ демонструють перехід двовимірної системи з режиму «часткової непружності», яка характеризується залежністю τ⁻¹h-ph ∝ T² до режиму малокутового розсіювання, що описується залежністю τ-1h-ph ∝ T⁵ з підвищенням температури. В більш високих магнітних полях залежність τ⁻¹h-ph ∝ T³ змінюється на -ph -ph ( ) τh hT . Обговорюються можливі варіанти пояснення таких спостережень