论全球化语境中我国的饮食消费文化

全球化作为客观历史发展过程,核心是"复杂的联结".全球化语境中的饮食消费文化具有三项基本特征:空前的丰盛性、膨胀的求新性、危险的整体性.对其的批判可以从浪费、盲目和殖民三方面展开,以积极建设全球化语境中的当代审美文化.     

快速更换大钟吊杆和拉杆的措施

液压炉顶大钟吊杆和拉杆出现弯曲会影响大钟和大钟斗的密封 ,从而影响高炉的稳定顺行。结合安钢 6# 高炉大钟吊杆和拉杆弯曲后的实例检修 ,旨在说明在日常检修中可以实现快速更换大钟吊杆和拉杆 ,并提出在快速更换过程中的注意事项     

Partial redundancy elimination for access expressions by speculative code motion

We present a new memory access optimization for Java to perform aggressive code motion for speculatively optimizing memory accesses by applying partial redundancy elimination (PRE) techniques. First, to reduce as many barriers as possible and to enhance code motion, we perform alias analysis to identify all the regions in which each object reference is not aliased. Secondly, we find all the possible barriers. Finally, we perform code motions in three steps. For the first step, we apply a non‐speculative PRE algorithm to move load instructions and their following instructions in the backwards direction of the control flow graph. For the second step, we apply a speculative PRE algorithm to move some of them aggressively before the conditional branches. For the third step, we apply our modified version of a non‐speculative PRE algorithm to move store instructions in the forward direction of the control flow graph and to even move some of them after the merge points. We implemented our new algorithm in our production‐level Java just‐in‐time compiler. Our experimental results show that our speculative algorithm improves the average (maximum) performance by 13.1% (90.7%) for jBYTEmark and 1.4% (4.4%) for SPECjvm98 over the fastest algorithm previously described, while it increases the average (maximum) compilation time by 0.9% (2.9%) for both benchmark suites. Copyright © 2004 John Wiley & Sons, Ltd.     

Application of the phase extension method in virus crystallography

The procedure for phase extension (PX) involves gradually extending the initial phases from low resolution (e.g. ～8?Å) to the high-resolution limit of a diffraction data set. Structural redundancy present in the viral capsids that display icosahedral symmetry results in a high degree of non-crystallographic symmetry (NCS), which in turn translates into higher phasing power and is critical for improving and extending phases to higher resolution. Greater completeness of the diffraction data and determination of a molecular replacement solution, which entails accurately identifying the virus particle orientation(s) and position(s), are important for the smooth progression of the PX procedure. In addition, proper definition of a molecular mask (envelope) around the NCS-asymmetric unit has been found to be important for the success of density modification procedures, such as density averaging and solvent flattening. Regardless of the degree of NCS, the PX method appears to work well in all space groups, provided an accurate molecular mask is used along with reasonable initial phases. However, in the cases with space group P1, in addition to requiring a molecular mask, starting the PX at a higher resolution (e.g. 6?Å) overcame the previously reported problems due to Babinet phases and phase flipping errors.     

Hydrocarbon flame inhibition by C6F12O (Novec 1230): Unstretched burning velocity measurements and predictions

This study experimentally and numerically determined the unstretched laminar burning velocity of premixed CH₄-air and C₃H₈-air flames with added C₆F₁₂O (Novec 1230). High-speed shadowgraphy of spherically expanding flames provided the burning velocity as a function of stretch, which was extrapolated to zero-stretch conditions using non-linear methods. Unstretched burning velocities predicted using a recently assembled kinetic mechanism were generally in good agreement with the measurements, but tended to have poorer agreement for highly-inhibited very lean flames. To benchmark the performance of C₆F₁₂O, measured burning velocities were compared to previously measured burning velocities of premixed flames inhibited by CF₃Br (Halon 1301). The two agents provided similar reductions in the burning velocity of rich flames, whereas CF₃Br provided greater reductions when added to stoichiometric and lean flames. Lastly, experiments and simulations showed the influence of water vapor on the burning velocity of lean C₃H₈-air flames with added C₆F₁₂O. The presence of water vapor in the oxidizer increased the burning velocity by up to 23% when the fluorine to hydrogen ratio of the reactant mixture was greater than unity.     

某水库排沙孔检修闸门更换方案比选研究

结合某70 m高混凝土双曲薄拱坝排沙孔进口检修闸门更换的方案比选,详细对比了放空水库方案与水下更换方案的优缺点。对比发现,两方案均不可行。放空水库方案主要是因为非技术方面的原因无法采用,水下浮体门封堵方案则存在一系列风险和限制条件,不适宜在本工程中采用。因此,下一步应加强水下修补技术的研究。     

Using Twitter® as source of information for dietary market research: a study on veganism and plant-based diets

Social media has experienced rapid growth in recent years and has been subjected of discussions on a wide range of topics including new lifestyles and eating habits, providing a great opportunity to obtain spontaneous consumer information. In this sense, the present work aimed to understand the perception of Twitter^® users about themes of veganism and plant-based diets. The social networking data mining methodology was applied to measure the relationship between both terms. The significant differences found were analysed using the global chi-square (χ²) test, and their sources of variation were investigated by the chi-square per cell. The results indicate that the vegan group's posts are more related to the categories of recipes, trends, criticism and negative comments about veganism, being more often citing sources when compared to the other group. The results of the plant-based diet group are more significantly related to the impacts of nutrition, physical activity and consumer health. In conclusion, Twitter^® has proved to be an interesting tool for obtaining data on (re) produced food publications on social media and their results can guide the market and the academic environment in creating new products, services and marketing strategies to answer the needs of specific consumers.     

An easy and eco-friendly method to fabricate three-dimensional Pd-M (Cu,Ni) nanonetwork structure decorated on the graphene nanosheet with boosted ethanol electrooxidation activity in alkaline medium

A new rapid and facile strategy for the preparation of Pd-Ni/G and Pd-Cu/G catalysts with a three-dimensional porous structure are presented in this paper. Both catalysts are formed using the same strategies in two steps: 1) The reduction of Ni(OH)₂ and Cu(OH)₂ to the metallic form on the surface of G/GC Electrode using the Zn/HCl reducer, 2) The galvanic displacement of Ni and Cu by Pd²⁺. Afterwards, three-dimensional Pd nanonetwork is generated on the glassy carbon electrode via the galvanic displacement. Compared to the other routes, this strategy depicts several advantages (e.g. fast way, facile, surfactant and reductant free, cheap, and eco-friendly.) Both catalysts are applied towards Ethanol Oxidation Reaction (EOR). Both porous structures show higher electrocatalytic activity and stability toward EOR compared to the commercial Pd/C. The extraordinary catalytic activity and durability of the both proposed catalysts for EOR can be related to the two vital reasons:1) The combination of Ni and Cu with Pd will efficiently promote the catalytic performance of Pd-Ni/G and Pd-Cu/G samples due to synergetic effects. 2) The porous structure of the as-prepared catalysts renders a high surface area and leads easier mass transport through the pores.     

Age replacement policy in a random environment using systemability

Preventive maintenance is a group of maintenance policies based on preventive actions in order to predate the failure of a component or a system. Usually, these policies are designed using a series of data related to the studied units. All policies do not consider the effect of the environment where the components or systems operate. In this article, one of the most used policies, the age replacement policy, is also discussed taking into consideration the environmental effects using an innovative concept, introduced by Pham, called systemability. Several numerical examples are carried out in order to illustrate the aim of this work. The importance of environmental factors is also demonstrated thanks to the application to a real case.