变形带及其对流体流动的影响

变形带表现为多孔砂岩中的一种普遍的局部应变类型，并以单一构造、带束（簇）和断层损伤带的形式出现。变形带的渗透率可降低0～6个数量级，因此可能影响流体流动。本文通过数学模型来揭示这一现象：对于变形带来说，在渗透率差异较高和（或）异常带较集中的情况下，明显影响生产速率。同样，野外观测揭示：沿着变形带和变形区域的孔隙度和渗透率迅速变化。另外，在野外所见的古流体剖面绝大部分没有受到或者仅仅部分受到变形带的影响。计算结果及野外观测结果综合表明：大多数情况下，在储层生产过程中，变形带的作用很小或者几乎可以忽略。由断裂作用和复杂断层解剖引起的结构混杂更容易形成除地层和动力学效应之外的生产问题。然而，变形带的排列及方向可能对流动类型及储层驱替有影响。当变形带引起生产问题时，可利用水力压裂的办法解决。     

A Pressure Driven Nanoconcentrator with Anti-Clogging Behavior for Recovery of Bio-Nanoparticles

This study proposes a counterflow nanoconcentrator (nC) with anti-clogging behavior as a concept for concentration of nano-sized particles, with the purpose of concentrating viruses in water samples and improving the sensitivity of subsequent detection. The nC incorporates penetrating nanochannels of varying cross section arranged between aerofoil-shaped micropillars distributed in an elliptical shape, with critical separation in the nanoscale. Continuum theory and discrete lattice Boltzmann method are used to describe the flow through channels at a critical width of 40 nm. Nanofluidic and microfluidic performance characteristics of the concentrator were investigated by simplifying the filtrate channels as effective fluidic lumped resistance elements. Comparison between nC units and microconcentrator units showed that the performance of the nC is consistent with that of the counterflow microconcentrator. But due to the large fluidic resistance exerted by the nC, operational parameter (pressure) and design parameters must be changed to preserve the anti-clogging behavior. Through a downscaling and a denser distribution of concentrating units compared with the microconcentrator, the results infer that the nC is capable of transporting a sufficient volume of liquid and is able to concentrate nanoparticles from water samples with reduced clogging risk and at high concentration efficiency.     

Spatial and symbolic factors in performance on the Trail Making Test.

Analyzed the relative contribution of spatial arrangement and symbolic complexity to performance of 24 young normal Ss (aged 20–51 yrs), 24 elderly normal Ss (aged 60–73 yrs), and 24 head-injured Ss (aged 18–47 yrs) on a trail making test (TMT). Test versions that permitted separation of spatial and symbolic factors were created. There were strong main effects of both spatial arrangement, symbolic complexity, and group. There was a significant interaction effect between spatial arrangement and symbolic complexity and between group and symbolic complexity. The relative difficulty of Forms A and B on the TMT may be due to differences in symbolic complexity and spatial arrangement and to interactions between these factors. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

全新32位微控制器实现真正的单芯片DRM 数字音频编解码器

随着近几年数字音频产品的爆炸性增长,市场上出现了很多芯片或者芯片组来满足更高级的播放器要求。但是有些进入数字音频市场的产品也存在一些陷阱,事情并不是像选取适当的处理器硬件那样简单。     

The energy intensity target in China's 11th Five-Year Plan period—Local implementation and achievements in Shanxi Province

Facing the mounting pressure on energy security and increasing environmental concerns about air pollution and climate change, the Chinese government set a mandatory goal of 20% reduction of energy intensity in its 11th Five-Year Plan period (FYP, 2006–2010). In this paper we use Shanxi province to illustrate how policies and measures are implemented in practice at a provincial level as a response to the National FYP issued by the central government. Local policies are described and their effects are analyzed. We compare reported energy saving achievements with our own estimates and conclude that the achievements in Shanxi probably have been substantial since the start of the 11th FYP period. The most important measures taken by provincial and local governments seem to be in the secondary sector, such as Top-200/Top-1000 program and phasing out outdated technologies. However, Shanxi has still a long way to go to achieve satisfactory energy use. Further improvement of energy intensity will require continuing efforts. Although many measures are necessary, improving the energy efficiency in heavy industries and reducing the dependence on these industries should be particularly effective.     

Can Drying Be an Alternative Tissue Preservation Method in Cancer Research Biobanking?

The currently available methods for conservation of biobank material are mainly based on formalin fixation or the use of different freezing techniques. For molecular biological analysis, it is common to use quick freezing and low-temperature storage of the tissue materiel. This is a very energy-intensive and expensive method that requires advanced infrastructure, including monitoring and control procedures. The purpose of this work has been to study drying as an alternative process to cryogenic storage of undried biobank material, especially for use in cancer research groups.

Fast freezing has been shown to be suitable to preserve the integrity of RNAs, while traditional formalin fixation preserves proteins and thus morphology in a good way. Various fresh-harvested murine tissues, such as lung, heart, skeletal muscle, liver, and kidney, were quickly frozen in liquid nitrogen and then subsequently dried at +5°C and ?10°C, respectively, in a heat pump dryer. After drying, the RNA integrity was measured. The dried material was then stored for five months at +4°C and ?20°C in commercial refrigerators, with subsequent measurement of RNA integrity. Dried materials were also evaluated with light microscopy and by electron microscopy with respect to tissue and cell structure. The same pattern was found for all five murine tissues. We conclude that drying at temperatures below 0°C is most careful to preserve the RNA integrity, with approximately the same RIN score of dried and non-dried samples for all five tissues. What characterized the general pattern of stored samples is that drying leads to a preservation of RNA integrity. Moreover, architecture in tissue resembled normal sections prepared from fresh tissue. In some places in the rim of the tissue sample, the lung tissue revealed alveolar-like morphology. In the electron microscope, few organelles other than the nuclei could be identified. Drying of biological material is a promising and cost-effective method for biobanks that store tissue, compared to cryogenic storage of undried material. Degradation of RNA, measured by the RIN number, is a critical factor in storing biobank tissue. In low-temperature dried material, the RIN factor is at the same level as storage of undried material at cryogenic temperatures, which is the common way of storing biobank material today. In this study, a heat pump dryer was used successfully to establish drying temperatures below and above the freezing point of the material. Further work has to be done in order to study different drying methods, drying conditions, and drying costs.     

Biomagnification of mercury in selected species from an Arctic marine food web in Svalbard

Concentrations and biomagnification of total mercury (TotHg) and methyl mercury (MeHg) were studied in selected species from the pelagic food web in Kongsfjorden, Svalbard. Twelve species of zooplankton, fish and seabirds, were sampled representing a gradient of trophic positions in the Svalbard marine food web. TotHg and MeHg were analysed in liver, muscle and/or whole specimens. The present study is the first to provide MeHg levels in seabirds from the Svalbard area. The relative MeHg levels decreased with increasing levels of TotHg in seabird tissues. Stable isotopes of nitrogen (δ¹⁵N) were used to determine the trophic levels and the rate of biomagnification of mercury in the food web. A linear relationship between mercury levels and trophic position was found for all seabird species combined and their trophic level, but there was no relationship within species. Biomagnification factors were all > 1 for both TotHg and MeHg, indicating biomagnification from prey to predator. TotHg levels in the different seabirds were similar to levels detected in the Kongsfjorden area in the 1990s.     

Reductions in greenhouse gas emissions and cost by shipping at lower speeds

CO₂ emissions from maritime transport represent a significant part of total global greenhouse gas (GHG) emissions. According to the International Maritime Organization (Second IMO GHG study, 2009), maritime transport emitted 1046 million tons (all tons are metric) of CO₂ in 2007, representing 3.3% of the world's total CO₂ emissions. The International Maritime Organization (IMO) is currently debating both technical and market-based measures for reducing greenhouse gas emissions from shipping. This paper presents investigations on the effects of speed reductions on the direct emissions and costs of maritime transport, for which the selection of ship classes was made to facilitate an aggregated representation of the world fleet. The results show that there is a substantial potential for reducing CO₂ emissions in shipping. Emissions can be reduced by 19% with a negative abatement cost (cost minimization) and by 28% at a zero abatement cost. Since these emission reductions are based purely on lower speeds, they can in part be performed now.