The charge trapping/emission processes in silicon nanocrystalline nonvolatile memory assisted by electric field and elevated temperatures

In this work, the influence of elevated temperatures on charge trapping in Si nanoclusters located in oxide layer of MOS structure has been comprehensively studied. The samples with one layer of nanocrystals in the oxide have been studied using the modular data acquisition setup for capacitance-voltage measurements. The memory window formation and memory window retention experimental methods were used with the aim to study the trapping/emission processes inside the dielectric layer of MOS capacitor memory within the defined range of elevated temperatures. The trap activation energy and charge localization were determined from measured temperature dependences of charge retention. The electric field dependence of the activation energy with subsequent charge emission law have been determined

Динамика информационных нагрузок в школе и психофункциональное развитие детей столичного мегаполиса

In article there are studying of dynamics of information loadings in school and level of psycho-functional development of children of the capital megalopolis are given. It is shown that different forms of school training (traditional, gymnasia and lycee classes) have different impact on cognitive and psycho physiological indicators of the Moscow schoolboys.Приводятся результаты изучения динамики информационных нагрузок в школе и уровня психофункционального развития детей столичного мегаполиса. Показано, что разные формы школьного обучения (традиционные, гимназические и лицейские классы) оказывают разное воздействие на когнитивные и психофизиологические показатели московских школьников

Параметры школьной среды как фактор, негативно влияющий на здоровье учащихся

The article studies the influence of environmental factors on the children′s organism of whose health is an indicator of the ecological situation. School buildings and facilities in many respects do not meet the standards imposed on such institutions. In this research, measurements were made of physical factors of the school environment, assess the health status of students.Статья посвящена изучению влияния факторов внешней среды на организм детей, состояние здоровья которых является индикатором экологической ситуации. Школьные здания и помещения по многим параметрам не соответствуют нормативам, предъявляемым к таким учреждениям. В работе представлены результаты произведенных измерений физических факторов школьной среды и показателей, характеризующих уровень здоровья учащихся

Multiband light emission and nanoscale chemical analyses of carbonized fumed silica

Fumed silica with a specific area of 295 m(2)/g was carbonized by successive phenyltrimethoxysilane treatments followed by annealing in inert atmosphere up to 650 degrees C. Emission, excitation, kinetics, and photo-induced bleaching effects were investigated by steady state and time-resolved photoluminescence spectroscopies. The local chemistry was also studied by infrared transmission spectroscopy. Strong ultraviolet and visible photoluminescence was observed in the samples after the chemical treatments/modifications and thermal annealing. It has been shown that ultraviolet photoluminescence in chemically modified fumed silica is associated with phenyl groups, while near ultraviolet and visible emission in annealed samples originated from inorganic pyrolytic carbon precipitates dispersed in the silica host matrix. Two types of emission bands were identified as a function of the annealing temperature: one is in the near UV and the other is in the visible range. Based on the emission/excitation analysis of these two bands, as well as on correlations with the synthesis conditions, a structural-energy concept of light-emitting centers has been proposed. According to this model, the light-emitting centers are associated with carbon clusters that can be bonded or adsorbed on the silica surface. This has been validated by a detailed (S)TEM-electron energy-loss spectroscopy study, confirming the inhomogeneous distribution of nanoscale carbon precipitates at the surface of the silica nanoparticles. These carbon precipitates are mostly amorphous although they possess some degree of graphitization and local order. Finally, the fraction of sp(2) carbon in these nanoclusters has been estimated to be close to 80%. Published by AIP Publishing

Shot noise in tunneling transport through molecules and quantum dots

We consider electrical transport through single molecules coupled to metal electrodes via tunneling barriers. Approximating the molecule by the Anderson impurity model as the simplest model which includes Coulomb charging effects, we extend the ``orthodox'' theory to expand current and shot noise systematically order by order in the tunnel couplings. In particular, we show that a combined measurement of current and shot noise reveals detailed information of the system even in the weak-coupling limit, such as the ratio of the tunnel-coupling strengths of the molecule to the left and right electrode, and the presence of the Coulomb charging energy. Our analysis holds for single-level quantum dots as well.Comment: 8 page

Effect of chemical and radiofrequency plasma treatment on photoluminescence of SiOx films

Effect of hydrogen radiofrequency plasma and chemical treatment on photoluminescence (PL) spectra of SiOx layers containing Si nanoparticles are investigated. Considerable PL intensity growth in the samples containing Si nanocrystals (nc-Si-SiOx) after plasma treatment is observed. The process saturates for time of 15 minutes. Chemical treatment in ammonia and acetone vapour before thermal annealing of SiOx layers leads to the considerable changes in PL spectra effecting both on the band shape and on the intensity. The possibility of controlled changes in PL spectra in nc-Si-SiO₂ layers is shown

Состояние здоровья школьников в условиях мегаполиса и села

In article comparative research a state of the schoolboys health living and trained in different social and ecological conditions of a capital megacity, city around Moscow and village scales is resulted. The description of ecological conditions of some areas of a capital megacity, a city situated near Moscow and village of the Kaluga region is given. The data on level and in frequency of occurrence of diseases among schoolboys of different age groups of conditions of a city and village is cited. On the basis of the received results different groups on level of adaptation and levels of psychosomatic health are revealed.Проведено сравнительное исследование состояние здоровья школьников, проживающих и обучающихся в разных социально-экологических условиях столичного мегаполиса, среднего по масштабам города и села. Дается описание экологической обстановки некоторых районов столичного мегаполиса, подмосковного города и села Калужской области. Приведены данные по уровню и частоте встречаемости заболеваний среди школьников разных возрастных групп условий города и села. На основании полученных результатов выявлены разные группы по уровню адаптации и уровням психосоматического здоровья

Maximal L p -regularity for the Laplacian on Lipschitz domains

We consider the Laplacian with Dirichlet or Neumann boundary conditions on bounded Lipschitz domains ?, both with the following two domains of definition:D1(?) = {u ? W1,p(?) : ?u ? Lp(?), Bu = 0}, orD2(?) = {u ? W2,p(?) : Bu = 0}, where B is the boundary operator.We prove that, under certain restrictions on the range of p, these operators generate positive analytic contraction semigroups on Lp(?) which implies maximal regularity for the corresponding Cauchy problems. In particular, if ? is bounded and convex and 1 < p ? 2, the Laplacian with domain D2(?) has the maximal regularity property, as in the case of smooth domains. In the last part,we construct an example that proves that, in general, the Dirichlet–Laplacian with domain D1(?) is not even a closed operator

Current Fluctuations and Electron-Electron Interactions in Coherent Conductors

We analyze current fluctuations in mesoscopic coherent conductors in the presence of electron-electron interactions. In a wide range of parameters we obtain explicit universal dependencies of the current noise on temperature, voltage and frequency. We demonstrate that Coulomb interaction decreases the Nyquist noise. In this case the interaction correction to the noise spectrum is governed by the combination $\sum_nT_n(T_n-1)$, where $T_n$ is the transmission of the $n$-th conducting mode. The effect of electron-electron interactions on the shot noise is more complicated. At sufficiently large voltages we recover two different interaction corrections entering with opposite signs. The net result is proportional to $\sum_nT_n(T_n-1)(1-2T_n)$, i.e. Coulomb interaction decreases the shot noise at low transmissions and increases it at high transmissions.Comment: 16 pages, 2 figure