Photoconduction and photocontrolled collective effects in the Peierls conductor TaS3_3

Light illumination of thin crystals of CDW conductor TaS$_3$ is found to result in dramatic changes of both linear ($G$) and nonlinear conduction. The increase of $G$ is accompanied by suppression of the collective conduction, growth of the threshold field $E_T$, and appearance of the switching and hysteretic behavior in the nonlinear conduction. The effects in the nonlinear conduction are associated with increase of CDW elasticity due to illumination that leads in particular to appearance of a relation $E_T\propto G^{1/3}$ expected for the one-dimensional pinning.Comment: RevTeX4, 4 pages, 4 postscript figures. Revised manuscript, new title, new Fig. 1, text corrections. Journal reference adde

Огляд ринку сонячної енергетики України: стан та комерційні перспективи

Today, solar energy is called the energy of the future, and many companies make significant investments in the construction of such power plants. The article provides an overview of the commercial perspectives of this market, determines the size of investments and the return on the project. Modern solar panels are able to operate without additional investments for decades and, from the point of view of the authors, in the long term the electricity generated in this way will not only cost-effective, and extremely profitable. The global situation in the energy market and in the field of renewable energy, in particular, is considered. The reasons that triggered the development of renewable energy sources, the key of which are the dangers of nuclear energy and environmental pollution, are explained. Along with this, we consider the structure of the market of renewable energy sources in Ukraine, where the geographic location is favorable for the implementation of solar energy projects. The climate of Ukraine is characterized by a large number of sunny days: in terms of insolation, Ukraine is significantly superior to European leaders in solar energy. This basic factor allows us to talk about the commercial perspectives of solar power generation projects implemented in Ukraine. Against the background of these perspectives is considered the structure of the energy market in Ukraine and the investment attraction of renewable energy projects. Market trends in the development of the solar energy market were discussed, which are expected to contribute to the development of new market niches, such as after-sales services, as well as the transformation of existing business models against the backdrop of the introduction of new facilities.Сьогодні багато хто називає сонячну енергію енергією майбутнього, і багато компаній вкладають значні інвестиції в будівництво таких електростанцій. У статті наведено огляд комерційних перспектив цього ринку, визначені розміри інвестицій і окупність проекту. Сучасні сонячні батареї в змозі працювати без додаткових капіталовкладень десятки років і, з точки зору авторів, в довгостроковій перспективі електроенергія, згенерована таким чином, стане не просто рентабельною, а надприбутковою. У статті розглянута глобальна ситуація в сфері ринку енергетики і в сфері відновлюваних джерел енергії, зокрема. Пояснені причини, які послужили поштовхом у розвитку відновлюваних джерел енергії, ключовими з яких є небезпека атомної енергетики і забруднення навколишнього середовища. На ряду з зазначеним, розглянута структура ринку відновлюваних джерел енергії на Україні, географічне розташування якої сприятливо для реалізації проектів сонячної енергетики. Для клімату України характерна велика кількість сонячних днів: за ступенем інсоляції Україна значно перевершує європейських лідерів в сонячній енергетиці. Зазначене є базовим фактором, що дозволяє говорити про комерційні перспективи проектів сонячної електрогенерації, що реалізуються в Україні. На тлі зазначених перспектив розглянута структура енергетичного ринку на Україні і інвестиційна привабливість проектів відновлюваної енергетики. Обговорено ринкові тенденції розвитку ринку сонячної енергетики, які, як очікується, на тлі введення нових об'єктів сприятимуть розвитку нових ринкових ніш, таких як сервісне обслуговування, а також трансформації існуючих бізнес-моделей

Experimental evidence of ageing and slow restoration of the weak-contact configuration in tilted 3D granular packings

Granular packings slowly driven towards their instability threshold are studied using a digital imaging technique as well as a nonlinear acoustic method. The former method allows us to study grain rearrangements on the surface during the tilting and the latter enables to selectively probe the modifications of the weak-contact fraction in the material bulk. Gradual ageing of both the surface activity and the weak-contact reconfigurations is observed as a result of repeated tilt cycles up to a given angle smaller than the angle of avalanche. For an aged configuration reached after several consecutive tilt cycles, abrupt resumption of the on-surface activity and of the weak-contact rearrangements occurs when the packing is subsequently inclined beyond the previous maximal tilting angle. This behavior is compared with literature results from numerical simulations of inclined 2D packings. It is also found that the aged weak-contact configurations exhibit spontaneous restoration towards the initial state if the packing remains at rest for tens of minutes. When the packing is titled forth and back between zero and near-critical angles, instead of ageing, the weak-contact configuration exhibits "internal weak-contact avalanches" in the vicinity of both the near-critical and zero angles. By contrast, the stronger-contact skeleton remains stable

Associated heavy quarks pair production with Higgs as a tool for a search for non-perturbative effects of the electroweak interaction at the LHC

Assuming an existence of an anomalous triple electro-weak bosons interaction being defined by coupling constant $\lambda$, we calculate its contribution to interactions of the Higgs with pairs of heavy particles. Bearing in mind experimental restrictions $-0.011 < \lambda < 0.011$ we present results for possible effects in processes $p\,p \to W^+ W^- H,\,p\,p \to W^+ Z H,\,p\,p \to W^- Z H,\,p\,p \to \bar t t H$, $p p \to \bar b b H$. Effects could be significant with negative sign of $\lambda$ in associated heavy quarks $t,\,b$ pairs production with the Higgs. In calculations we rely on results of the non-perturbative approach to a spontaneous generation of effective interactions, which defines the form-factor of the three-boson anomalous interaction.Comment: 6 pages, 2 figures, few typos corrected, references adde