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To study the effect of various parameters of wafer-level strained SOI on the stress of the top Si layer, strained-SOI wafers were successfully fabricated by depositing highly stressed SiN films. Raman tests were performed on the top layer of strained Si to measure the strain. ANSYS software was applied to simulate the effects of parameter changes of highly stressed SiN films, the variation of the material parameters of each layer, and the effect of scaling effect under the thickness variation on the top layer strained Si. The simulation results show that the existence of the scale effect of the thin film material affects the stress of the top Si layer, the thicker the highly stressed SiN film is and the larger the stress values are, the larger the strain of the top Si layer is; and the thicker the SOI wafer substrate Si is, the smaller the strain of top Si layer is, so that the effect of substrate Si should also be considered in the wafer-level SOI strain model. Finally, the strain model is optimized using experimental measurements, and the model calculation error is approximately reduced by 40%. [ABSTRACT FROM AUTHOR]

In this paper, we proposed a method of introducing globally uniaxial strain into SOI(silicon-on-insulator) wafers, and the strain mechanism was discussed. Based on the size effect of internal-stress of SiN film, uniaxial strain was introduced in SOI layer by the formation of SiN bar array which width and the spacing were 1.5 μm and 3.0 μm on the whole surface of He+ implanted SOI wafer. Polarized Raman spectroscopy was adopted to reveal the uniaxial character of the introduced strain. In the crystallographic orientation of [100] and [110], uniaxially tensile strain of 0.7613% and 0.5125% was achieved respectively. [ABSTRACT FROM AUTHOR]

Background: Climate change and increasing anthropogenic pressure are two of the major drivers of increasing extreme events like droughts and floods. To deal with the increasing number of flooding events hitting Europe in the last few decades, around twenty years ago the European Commission started to develop ad-hoc legislation to reduce flood risk by mapping flood hazard and risk areas, such as the Directive 2007/60/EC on the Assessment and Management of Flood Risk. This Directive looks to identify regions where flood management strategies should be prioritized. Despite this holistic approach, flaws connected to the consideration of sediment transport and morphological changes in rivers exist, leading to potential underestimations of the impact of floods affecting active watercourses or areas subjected to frequent morphological changes. Results: By discussing six examples related to European lowland and mountain watercourses affected by significant floods in the last 20 years, the present mini-review aims to provide additional evidence on the need for a rethinking of flood risk mapping, moving from a "clear water" perspective to a more integrated approach, where the interactions between all the fluvial components (water, sediment, biota, and humans) are adequately considered. Conclusions: The examples reported here show the importance of considering sediment and wood in flood risk management, suggesting the need for integrating flood-related studies with other disciplines like geomorphology and ecohydrology. [ABSTRACT FROM AUTHOR]

Although 2,4,6-trinitrotoluene (TNT) is a dangerous carcinogen in environmental pollution, information on the reproductive effects of TNT explosive contamination is limited. To explore the possible ovarian effects, TNT explosive-exposed rat models were established, and Wistar female rats were exposed to low and high TNT (40 g and 80 g, air and internal) explosives. After a month of exposure, the estrous cycle, ovarian histopathology, and follicle counting were conducted. Serum hormones follicle-stimulating hormone (FSH), luteinizing hormone (LH), anti-Müllerian hormone (AMH), progesterone, testosterone, and estradiol were detected, and the mRNA and protein expression of steroidogenic enzymes were measured. The results showed that the diestrus phase duration was significantly (P < 0.05) increased in the high TNT-exposed groups. In addition, the proportions of preantral follicles were significantly (P < 0.05) decreased in the high TNT-exposed groups, as well as the proportions of atretic follicles. The serum estradiol levels were significantly (P < 0.05) increased, and the follicle-stimulating hormone and luteinizing hormone levels were significantly (P < 0.05) decreased in the high TNT-exposed groups. The mRNA levels of steroidogenic acute regulatory protein (Star), cytochrome P450 cholesterol side chain cleavage (Cyp11a1, Cyp17a1 and Cyp19a1), hydroxysteroid dehydrogenase 3b (Hsd3b) and steroidogenic factor-1 (SF-1) were significantly (P < 0.05) increased in the TNT-exposed groups. The protein levels of Star, Cyp11a1 and Hsd3b were increased (P < 0.05) in the TNT-exposed groups. These results indicate that the exposure of rats to TNT explosive can subsequently affect ovarian follicle development, suggesting that the mechanism may involve disrupting steroidogenesis. [ABSTRACT FROM AUTHOR]

In this paper, based on the straining mechanism of plastic deformation and the flexible slip properties of buried SiO2 layers for the sSOI wafer, a model for the introduced strain of sSOI fabricated by the deposition of high-stress SiN film is established by the arc method and mechanical relations. This model includes strains generated by both wafer bending and stretching/compression of the stress film. The model calculation results are basically consistent with the experimental results as verified by experimental data and Raman tests. [ABSTRACT FROM AUTHOR]

Nitrate, existing as inorganic anions in water, possesses high water-solubility and has caused lots of contaminations around the world. It is thus extremely urgent to develop an effective method to effectively remove nitrate from water in a sustainable way. In this study, chitosan-ethylene glycol hydrogel (CEGH) was synthesized using the repeated freezing-thawing procedure. A range of batch sorption experiments were conducted to evaluate CEGH as a nitrate sorbent. The adsorption isotherms of nitrate onto CEGH followed the Langmuir model with coefficient of determination of 0.98 and a maximum Langmuir adsorption capacity of 49.04 mg/g, which is higher than that of other adsorbents. The adsorption of nitrate onto CEGH was affected by pH value and temperature. The results indicate that the main removal mechanism was polarity of CEGH molecules given by functional group O–H and N–H and hydrogen bond interaction between CEGH and nitrate molecules under acidic conditions. Therefore, CEGH, a biodegradable carbon-rich adsorbent, can be widely applied to remove nitrate in wastewater treatment and water body remediation. [ABSTRACT FROM AUTHOR]

As much wind power is connected to the power system, the accommodation of the wind power in the power grids becomes a huge challenge to the operation model of China's power system. Releasing and improving the flexibility of the power system will be necessary and important to enable the accommodation of power generated with renewable energy sources, which is connected to the power grids on a large scale and accounts for a high proportion. The paper, with North Hebei as an example, discusses the relationship between the demand for the flexibility of thermal power units and the accommodation of wind power. This paper further analyzes the demand for peak load regulation in North Hebei at both the present and the future as well as the characteristics of power sources in the power grids of North Hebei and the technical potential of power generation. It also compares the quantity of curtailed power before and after the flexibility-oriented transformation of thermal power units in North Hebei and calculates the minimum technical output of thermal power under different levels of accommodation of wind power. The research shows that the peak load regulating resources in the power grids of North Hebei boast huge potential, but in the long term, to achieve the objective of a 10% curtailment rate of power generated with renewable energy sources, the minimum technical output of condensing units must be lower than the internationally advanced level of 25%. So, it is difficult to fulfill the said objective solely relying on the strengthened transformation of generating units. To reach the level of 5% curtailment rate of power generated with renewable energy sources, the minimum technical output must achieve breakthrough improvement, which requires continuous technological innovation and power flexibility in close coordination. [ABSTRACT FROM AUTHOR]

Here, we successfully developed a template-free way to fabricate hierarchically porous magnesium oxide (MgO) and carefully investigated the adsorption behavior for phosphate and methyl orange (MO). The average pore size and the percentage porosity decreased with the increase in the feeding ratio of Mg2+/NH3. Among the three samples, MgO-25 shows the highest surface area of 63 m2 g−1 determined by the mercury intrusion method, and MgO-50 exhibits the highest BET surface area of 121 m2 g−1. For all the MgO samples, the adsorption process follows the pseudo second-order and Langmuir isotherm for phosphate, while pseudo second-order and the Freundlich isotherm for MO. Among the investigated samples, MgO-25 shows the most maximum removal capacity of 478.5 mg g−1 for phosphate and the highest removal capacity of 4483.9 mg g−1 for MO. This study compromises a low-cost and convenient dual function material for excellent water remediation of multiple industries. [ABSTRACT FROM AUTHOR]

Frequent occurrence of landslides in the Chinese Loess Plateau has been influenced by the changes of water conditions. This paper, based on in-situ water scouring experiments under various slope gradients, cross-sectional discharge shapes and flow quantities, analyzed the rill flow information characteristics on a loess slope and its driving factors for anti-scourability of the loess stratum. The results show that the critical erosion slope gradient for the loess stratum (Q3) is about 24° and the mean erosion rate under half-round cross-sectional discharge is smaller than that under rectangular discharge. The relationship between flow quantity and mean erosion rate is linear and is positively correlated. Mechanical subsurface erosion was the primary condition responsible for water scouring on loess slopes because of stronger runoff channels such as vertical joints and large amounts of macro void caused by plants and animals. Loess anti-scourability is a significant issue to advance the research for soil and water conservation in the Loess Plateau of China. [ABSTRACT FROM AUTHOR]