Nonrelativistic Multiferroicity in the Nonstoichiometric Spin s=1/2 Spiral Chain Cuprate LiCu2O2

We argue for a recently observed puzzling multiferroic behavior in s=1/2 1D chain cuprate LiCu2O2 with edge-shared arrangement of CuO4 plaquettes and incommensurate spiral spin ordering can be consistently explained if one takes into account the nonrelativistic exchange-induced electric polarization on the Cu2+ centers substituting for the positions native for the Cu1+ ions. These substituent centers are proved to be an effective probe of the spin incommensurability and magnetic field effects.Comment: 4 pages, 4 figure

Построение математической модели механизма привода ножа бумагорезальной машины БР-125

Побудована математична модель шарнірно-важільного механізму, як системи рівнянь, що характеризують стан механізму у кожен момент часу. Розроблено прикладну програму для проведення повного кінематичного аналізу на прикладі приводу одноножевої паперорізальної машини БР-125. Розроблено метод побудови математичної моделі шарнірно-важільного механізму 3-го класу з застосуванням ПЗ «Maple». Розглянуто методику дискретного розрахунку кінематичних характеристик ланок протягом робочого циклу. Проведено кінематичний розрахунок на прикладі приводу ОРМ БР-125. Створено базу для проведення силового аналізу.Construction of mathematical models of lever mechanism as a system of equations characterizing the mechanism in each moment. Development application for a full kinematic analysis on example of drive mechanism of one-knife papercutter machine BR-125. Developed an original method for constructing mathematical models of 3rd class lever mechanism on example of drive mechanism of one-knife papercutter BR-125. In the calculations used mathematical programming package «Maple». The method of calculating the kinematic characteristics of discrete units during the working cycle was described. This was determined by the coordinates of the fixed points of chains depending on the angle of rotation of the input chain using the method of geometric bindings. These were based on interpolated using Lagrandzh polynoms and differentiated for velocity and acceleration of these points. As a result of the work were obtained kinematic characteristics (speed, acceleration) of the main points of the mechanism and established framework for power analysis.Разработан метод построения математической модели шарнирно-рычажного механизма 3-го класса с применением ПО «Maple». Рассмотрена методика дискретного расчета кинематических характеристик звеньев в течении рабочего цикла. Проведен кинематический расчет на примере механизма привода ОРМ БР-125. Создана база для проведения силового анализа

Кинематическое исследование шарнирно-рычажного механизма привода ножа одноножевой резальной машины аналитическим методом

Складено рівняння побудови математичної моделі механізму ножа з погляду кінематики, в результаті рішення яких, побудовано графіки кутових переміщень, швидкостей і прискорень ланок механізму ножа на важелях.Contingency equation for constructing a mathematical model of the mechanism knife in terms of kinematics, as a result of which we construct graphs of angular displacement, velocity and acceleration levels of the mechanism knife to lever.Составлены уравнения построения математической модели механизма ножа с точки зрения кинематики, в результате решения которых, построены графики угловых перемещений, скоростей и ускорений звеньев механизма ножа на рычагах

Силовой анализ механизма привода ножа бумагорезальной машины БР-125

Розроблено метод силового розрахунку шарнірно-важільного механізму на основі проведеного кінематичного аналізу. Розроблено прикладну програму для проведення силового аналізу на прикладі приводу одноножевої паперорізальної машини БР-125. Розроблено метод проведення силового розрахунку шарнірно-важільного механізму 3-го класу з застосуванням ПЗ «Maple». Проведено силовий розрахунок на прикладі приводу ОРМ БР-125. Визначені всі навантаження, що діють на ланки механізму.Development a method of the power calculation lever mechanism on the basis of kinematic analysis. Development of the application, for the power analysis on example of one-knife papercutter machine BR-125. Lever mechanism of the machine in terms of the theory of machines and mechanisms related to the mechanisms of third grade - that is the most difficult on their analysis and synthesis. Having calculation programs such mechanisms using computer solves researchers and developers hands and gives ample opportunities in terms of improving these mechanisms and their optimization. Thus the subject of the article is relevant. Based on the traditional approach to calculate the force between groups Assyrians, the original method was proposed and developed a calculation program on the computer. The structure equations are the parameters of the drive mechanism parts. Thus it is possible to analyze the results of calculations for a given criteria and optimal parameters of the mechanism.Разработан метод проведения силового расчета шарнирно-рычажного механизма 3-го класса с применением ПО «Maple». Проведен силовой расчет на примере привода ОРМ БР-125. Определены все нагрузки, действующие на звенья механизма

Spice Addiction: Causes of Proliferation and Countermeasures

This article discusses issues related to trafficking of smoking mixtures, containing narcotic drugs and psychotropic substances or their synthetic analogues in the consumer market of the Russian Federation. The authors study the causes of distribution and consumption of narcotic mixtures by citizens and propose measures (organizational, legal, technical, educational and others) to combat trafficking in smoking mixtures hazardous to health

Energy dependence of Ti/Fe ratio in the Galactic cosmic rays measured by the ATIC-2 experiment

Titanium is a rare, secondary nucleus among Galactic cosmic rays. Using the Silicon matrix in the ATIC experiment, Titanium has been separated. The energy dependence of the Ti to Fe flux ratio in the energy region from 5 GeV per nucleon to about 500 GeV per nucleon is presented.Comment: 8 pages, 4 figures, accepted for publication in Astronomy Letter

Influence of measurement on the life-time and the line-width of unstable systems

We investigate the quantum Zeno effect in the case of electron tunneling out of a quantum dot in the presence of continuous monitoring by a detector. It is shown that the Schr\"odinger equation for the whole system can be reduced to Bloch-type rate equations describing the combined time-development of the detector and the measured system. Using these equations we find that continuous measurement of the unstable system does not affect its exponential decay to a reservoir with a constant density of states. The width of the energy distribution of the tunneling electron, however, is not equal to the inverse life-time -- it increases due to the decoherence generated by the detector. We extend the analysis to the case of a reservoir described by an energy dependent density of states, and we show that continuous measurement of such quantum systems affects both the exponential decay rate and the energy distribution. The decay does not always slow down, but might be accelerated. The energy distribution of the tunneling electron may reveal the lines invisible before the measurement.Comment: 13 pages, 8 figures, comments and references added; to appear in Phys. Rev.

Nonrelativistic Multiferrocity in the Nonstoichiometric Spin- 1 2 spiral-chain Cuprate LiCu2 O2

Puzzling multiferroic behavior observed recently in spin-1/2 one-dimensional chain cuprate LiCu2 O2 with edge-shared arrangement of CuO4 plaquettes and incommensurate spiral spin ordering is consistently explained to be a result of the nonrelativistic exchange-induced electric polarization on the Cu2+ centers substituting for the positions native for the Cu1+ ions. These substituent centers are proven to be an effective probe of the spin incommensurability and magnetic field effects. © 2009 The American Physical Society.The authors thank A. Loidl, U. Rößler, K. Dörr, R. Kuzian, and H. Rosner for discussions. The DFG and RFBR grants (No. 06-02-17242, No. 07-02-96047, and No. 08-02-00633) are acknowledged for financial support

Effect of the measurement on the decay rate of a quantum system

We investigated the electron tunneling out of a quantum dot in the presence of a continuous monitoring by a detector. It is shown that the Schr\"odinger equation for the whole system can be reduced to new Bloch-type rate equations describing the time-development of the detector and the measured system at once. Using these equations we find that the continuous measurement of the unstable system does not affect its exponential decay, $\exp (-\Gamma t)$, contrary to expectations based on the Quantum Zeno effect . However, the width of the energy distribution of the tunneling electron is no more $\Gamma$, but increases due to the decoherence, generated by the detector.Comment: Additional explanations are added. Accepted for publications in Phys. Rev. Let

A flaring X-ray pulsar in Dorado

A study of unusual gamma-ray bursts detected on March 5 and March 6, 1979 in the KONUS experiment on the Venera 11 and Venera 12 spacecraft shows their source to be flaring X-ray pulsar in Dorado