[en] Nonfibrillar soluble oligomers, which are likely to be transient intermediates in the transitions from monomers to amyloid fibrils, may be a toxic species in Alzheimer’s disease. For this reason it is very important to understand early events that direct assembly of amyloidogenic peptides. Using all-atom simulations with the GROMOS96 force field 43a1 in explicit water, we have recently shown that the oligomerization of Aβ_16–22 peptides obeys the dock-lock mechanism. We have also proposed a toy lattice model, which allows us to ascertain this conclusion using a much larger number of monomers. In this contribution we review our all-atom as well as lattice simulation results on the dock-lock mechanism of short peptides, which is probably a generic mechanism for fibril elongation of proteins and long peptides.

[en] As-grown diamond single crystals grown from Fe-Ni-C system under high temperature-high pressure were examined by transmission electron microscopy. There exist prismatic dislocation loops and concentric dislocation loops in the diamond, which are related to the nonequilibrium nature of the diamond synthesis process. The prismatic dislocation loops may be formed by vacancy condensation during rapid cooling from high temperature, and the Burgers vector of the dislocation is determined by diffraction contrast as 1/2<1 1 0>. Moire fringes formed by two overlapping (1 1 1) close-packed planes were used to study concentric dislocation loops. The concentric dislocation loops may be derived from thermal stress caused by the inclusions in the diamond, which cause a strain field due to the thermal contraction difference between the inclusions and the diamond during cooling from high temperature

[en] This paper, for the first time, compares the probabilistic optimal power flow (POPF) models targetingdifferent objectives -- minimizing the expected generation cost (EGC) and all-side risk (AR) or down side risk (DR)simultaneously. In the POPF models, wind power generation isconsidered in dispatching, the uncertainty of which can be explained by building a model to describe the stochasticcharacteristic of the forecast error. The distribution of the forecast error can be obtained by sampling from the historical error time series. The POPFsaresolvedusinggroup search optimizer with multiple producers (GSOMP), and a decision-making method TOPSIS is used to select the most suitablesolution. Simulation studies are conducted on a modified IEEE 118-bus power system with wind farms integrated, and the results show that the EGC-DR modelfind better solution compared tothe EGC-AR model. (paper)

[en] Along with the increasing penetration of wind power into power systems, more accurate forecast of wind power becomes more and more important for real-time scheduling and operation. This paper proposes a novel model for short-term wind power forecast based on singular spectrum analysis (SSA) and self-organizing maps (SOM). In order to deal with the impact of high volatility of the original time series, SSA is utilized to extract the mean trend from the original time series. After that, SOM is applied to select the similar segments from mean trend, which are then employed in local prediction by support vector regression (SVR). Simulation studies are conducted on real wind power time series, and the final results indicate that the proposed model is more accurate and stable than other models. (paper)

[en] An urban heat island (UHI) is an urban area where temperatures are higher than they are in the surrounding suburban areas. UHIs are of great scientific concern in the context of global environmental change. As a result of rapid economic development over the past three decades, the urban area in China has increased significantly. In the present study, to objectively determine the spatiotemporal patterns of UHI effects in Nanjing, surface brightness temperatures of the urban areas of Nanjing, which originated from remote sensing imagery of Landsat TM/ETM+ from 1988 to 2011, were inversed, and then the UHIs were extracted and graded by choosing a stable forest area as the suburban reference. When the results were combined with the surface meteorological data, a good relationship was found between the brightness temperatures and the ground-truth temperatures. The results of contrast analysis indicated that, over time, most of the heat islands of Nanjing remained over the central portions. The area and the intensity of the heat islands have both increased remarkably over the past 20 years

[en] Tin dioxide (SnO_2) thin films doped with Eu"3"+ are deposited by the sol-gel-dipcoating process on top of GaAs films, which is deposited by resistive evaporation on glass substrate. This heterojunction assembly presents luminescence from the rare-earth ion, unlike the SnO_2 deposition directly on a glass substrate, where emissions from the Eu"3"+ transitions are absent. The Eu"3"+ transitions are clearly identified and are similar to the observation on SnO_2 pressed powder (pellets), thermally treated at much higher temperatures. However, in the form of heterojunction films, the Eu emission comes along a broad band, located at higher energy compared to Eu"3"+ transitions, which is blue-shifted as the thermal annealing temperature increases. The size of nanocrystallites points toward quantum confinement or electron transfer between oxygen vacancies, originated from the disorder in the material, and trivalent rare-earth ions, which present acceptor-like character in this matrix. This electron transfer may relax for higher temperatures in the case of pellets, and the broad band is eliminated

[en] Fe_81-XCo_XGa₁₉ films, with x = 0-23 atom % Co, were deposited on Si(100) substrates, respectively, by the dc magnetron sputtering method. Film thickness (t_f) ranged from 30 to 400 nm. We have done the following experiments on those films: saturation magnetostriction (λ_S), high-temperature magnetic hysteresis, x-ray diffraction (XRD), atomic force microscopy, Auger-depth profile analysis, and plane-view and/or cross-section transmission electron microscopy. Our main finding is that if x increases from 0 to 19 atom % Co, λ_S increases from 56 to 152 ppm, and if x continues to increase from 19 to 23 atom % Co, λ_S decreases. These results indicate that the addition of Co in the Fe₈₁Ga₁₉ alloy is advantageous in enhancing λ_S, if x is the correct value. From XRD, the Fe₆₂Co₁₉Ga₁₉/Si(100) film comprises the A2 and B2 phases. The mechanism for large enhancement of λ_S in Fe₆₂Co₁₉Ga₁₉/Si(100) is related to an intrinsic origin. The t_f dependence of λ_S for the Fe₆₂Co₁₉Ga₁₉ films is that: [1] in the range of 110 ≤ t_f ≤ 400 nm, λ_S increases as t_f decreases; [2] in the range of 30 ≤ t_f ≤ 110 nm, λ_S decreases as t_f continues to decrease. The λ_S behavior in the regions [1] and [2] is explained based on the modified Neel model. Other physical properties of the Fe₆₂Co₁₉Ga₁₉ films include the following: saturation magnetization 4πM_S = 1.8 - 2.0 T, coercivity H_C = 35 - 64 Oe, Curie temperature T_C = 597 deg. C, planar (mean) grain size D_P = 29.6 nm, and columnar grain size D_L ≅ t_f.

[en] Novel 3D rods ZnO:Sm monophasic microcrystals have been synthesized by the microwave-assisted hydrothermal (MAH) method at 140 °C for 10 min. The experimental results revealed that concentration of samarium have a significant influence on the band gap and photocatalysis. On the other hand, the samarium in the ZnO semiconductor structure increases photodegradation activity. ZnO sample doped with 8% Sm³⁺ exhibited the best activity in the photodegradation of methylene blue dye when compared to that doped with 0–4 mol%. Enhanced photocatalytic activity was attributed to samarium, which inhibits the recombination of electron–hole pairs.

[en] In this work, Zn₂Eu_xTi_1−xO₄ and Zn_2−xEu_xTiO₄ (x = 0, 1, 2 and 3 mol%) powders were synthesized by complex polymerization method (CPM) and calcined at 1000 °C for 4 h. The powders were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV–Vis spectroscopy in the visible region and photoluminescence properties (PL). The photocatalytic properties were estimated by degradation of methylene blue (MB) dye when irradiated by UV lamps. X-ray diffraction results demonstrated the existence of Zn₂TiO₄ as primary phase and ZnO with secondary phase. According to diffractograms, the crystallite size varied between 49 and 67 nm. The Eu³⁺ ions introduction provides increased absorption in visible region, but the band-gap remains practically constant. In samples were observed an increased in photocatalysis with the increase in europium concentration, while in the Zn₂Eu_xTi_1−xO₄ samples, photocatalysis was reduced to europium concentrations greater than 1%. Eu³⁺ doped Zn₂TiO₄ provided a photoluminescent intensity increasing. CIE chromaticity coordinates confirm emission in the red region of the phosphor.

[en] We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H_2 are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps