关注建筑表皮——托马斯.赫尔佐格与赫尔佐格&德梅隆的建筑表皮设计手法比较

建筑表皮是近年在建筑界关注的热点,而托马斯·赫 尔佐格以及赫尔佐格＆德梅隆是在这个方面很活跃的世界级建 筑师。文章试从建筑表皮设计的角度出发对他们的设计手法进 行比较分析。尽管他们设计的出发点,材料的运用,以及对建筑 艺术与技术侧重的不同,造就了他们设计手法的差异。但他们都 设计出了优秀的作品,实现了技术与艺术完美的结合。     

Virtual pressure and virtual fugacity in catalysis and electrocatalysis

The generalized De Donder equation and the generalized Butler-Volmer equation can be used to understand and calculate so-called virtual pressure or virtual fugacity of reactants or products in catalytic and electrocatalytic cycles respectively. This illustrates the usefulness of general relations between kinetics and thermodynamics in sub-fields of catalysis that differ in their methodology.     

Processing parameter effect on the splat diameters of the droplets produced by liquid metal atomization using De Laval nozzle

Liquid metal atomization with De Laval nozzle is not a widely used technique to produce metallic powders. It appears as a versatile process to manufacture different particle sizes according to the processing parameters (gas pressure, melt nozzle diameter, De Laval nozzle diameter, etc.). However, few studies have focused on the understanding of the different stages of the process. During the atomization process two pressure stages can be distinguished: transition time (pressurization time) and stabilized stage (setting pressure).The aim of the work is to study the effect of the operating parameters on the splat diameter during these two stages. Copper (99.9 at. %) was atomized using different sets of operating parameters on smooth steel substrates. Different splat shapes and mean equivalent diameters are observed and have shown that they depended on both, the atomization parameters and the atomization time.     

Understanding corrosion via corrosion product characterization: II. Role of alloying elements in improving the corrosion resistance of Zn–Al–Mg coatings on steel

Corrosion products are identified on Zn, ZnMg and ZnAlMg coatings in cyclic corrosion tests with NaCl or Na₂SO₄ containing atmospheres. For Mg-containing alloys the improved corrosion resistance is achieved by stabilization of protective simonkolleite and zinc hydroxysulfate. At later stages, the formation of layered double hydroxides (LDH) is observed for ZnAlMg. According to thermodynamic modeling, Mg²⁺ ions bind the excess of carbonate or sulfate anions preventing the formation of soluble or less-protective products. A preferential dissolution of Zn and Mg at initial stages of corrosion is confirmed by in situ dissolution measurement. The physicochemical properties of different corrosion products are compared.     

Selective catalytic NOx reduction on Antimony promoted V2O5-Sb/TiO2 catalyst

Quantum chemical calculation was carried out to choose a promoter which can reduce the poisoning of V2O5/TiO2 catalysts by SO2.Several atoms were chosen as candidates and new catalysts were synthesized by impregnation method.The NOx conversion rate was measured at temperatures between 100 and 400 ℃ and poisoning effect was investigated.The most promising candidate promoter, Se, was excluded because of its high vapor pressure.On the other hand, Sb shows best promoting properties.Sb promoted catalyst reaches the maximum NOx conversion rate at 250 ℃.It also shows considerably enhanced resistance to poisoning of V2O5/TiO2 catalysts by SO2.     

<Emphasis Type="Italic">De novo</Emphasis> Synthesis vs. Sequestration: Negatively Correlated Metabolic Traits and the Evolution of Host Plant Specialization in Cyanogenic Butterflies

Larvae of Heliconius butterflies (Nymphalidae: Heliconiinae) feed exclusively on cyanogenic leaves of Passiflora (passion vine). Most Heliconius manufacture cyanogenic glycosides (cyanogens) and some species sequester cyanogens from host plants. We compare ability to sequester simple monoglycoside cyclopentenyl (SMC) cyanogens and manufacture aliphatic cyanogens in 12 Heliconius species, including larvae that are specialized (single host species) and generalized (many host species). All butterflies tested higher for cyanide concentrations when reared on plants that larvae can sequester from (SMC plants) than when reared on plants that larvae do not sequester from (non-SMC plants). Specialists in the sara–sapho clade sequestered SMC cyanogens from specific host plants at seven times that of Passiflora generalists fed the same hosts. In contrast, sara–sapho clade species reared on non-SMC plants had significantly lower cyanide concentrations from de novo synthesis than generalists fed the same plants. Furthermore, cyanogen analyses indicated that Heliconius sara butterflies reared on an SMC host had a greater proportion of sequestered SMC cyanogens (95.0%) than de novo-synthesized aliphatic cyanogens (5.0%). Thus, sequestration and de novo synthesis are negatively correlated traits. Results suggest that losing the ability to synthesize cyanogens has restricted sara–sapho clade species to specific hosts containing SMC cyanogens and explains dietary restriction in this clade. We dedicate our paper to the memory of the Honorable Miriam Rothschild, F.R.S., a friend, colleague and supporter of many young scientists. Her enthusiasm and delight in chemical ecology and natural history continued to the last weeks of her life.     

Characterization and Comparison of Major Urinary Proteins from the House Mouse, <Emphasis Type="BoldItalic">Mus musculus domesticus</Emphasis>, and the Aboriginal Mouse, <Emphasis Type="BoldItalic">Mus macedonicus</Emphasis>

Urine from the house mouse, Mus musculus domesticus, contains a high concentration of major urinary proteins (MUPs), which convey olfactory information between conspecifics. In wild populations, each individual expresses a different pattern of around 8 to 14 electrophoretically separable MUP isoforms. To examine whether other Mus species express MUPs and exhibit a similar level of individual heterogeneity, we characterized urinary proteins in urine samples from an aboriginal species, Mus macedonicus, captured from different sites in Turkey. Anion exchange chromatography and electrospray ionization mass spectrometry demonstrated that M. macedonicus urine contained a single major peak of mass 18,742 Da, and in contrast to M. m. domesticus, all individuals were the same. The M. macedonicus masses were not predicted from any known MUP gene sequence. Endoproteinase Lys-C (Lys-C) digestion of the purified M. macedonicus urinary protein followed by matrix assisted laser desorption time of flight (MALDI-TOF) mass spectrometry demonstrated that it shared considerable, but not complete, sequence homogeneity with M. m. domesticus MUPs. Three M. macedonicus Lys-C peptides differed in mass from their M. m. domesticus counterparts. These three peptides were further characterized by tandem mass spectrometry. The complete sequences of two were determined, and in conjunction with methyl esterification, the amino acid composition of the third was inferred, and the sequence narrowed down to three permutations. The complete M. macedonicus sequence contained a maximum of seven amino acid substitutions, discernible by tandem mass spectrometry, relative to a reference M. m. domesticus sequence. Six of these were on the surface of the molecule. Molecular modeling of the M. macedonicus sequence demonstrated that the amino acid substitutions had little effect on the tertiary structure. The differences in the level of heterogeneity between the two species are discussed in relation to their environment and behavior. In addition, the differences in protein structure allow speculation into molecular mechanisms of MUP function.     

基于绿色制造的切削机床-车间系统降噪研究

机床-车间系统是切削制造过程的基本生产单元,是实施绿色制造很关键的一环,从广义的角度看运转噪声和切削噪声都是机床噪声的一部分,基于绿色制造的机床-车间系统降噪关键在于降低机床噪声。本文对切削机床-车间系统的噪声特性进行了分析;总结了机床设计和制造（改造）过程中一些降低机床运转噪声的措施;提出了用调度等方法降低系统的切削噪声;并进行了实例分析。     

Reducing Nitrate Leaching to Groundwater in an Intensive Dairy Farming System

Dairy farming is one of the main contributors to nitrate leaching to groundwater, particularly on soils that are susceptible to leaching, such as light well-drained sandy soils. In the Netherlands, as in many other European countries, these soils are predominantly used for dairy farming. A prototype dairy farming system that has been implemented in practice in 1989 has continuously been adapted since then to meet environmental standards (i.e. the EU-standard of 50 mg NO₃⁻ l⁻¹) without reducing milk production intensity (11900 kg ha⁻¹). After an initial decline in nitrate concentration from 193 mg l⁻¹ to 63 upon implementation, it subsequently ‘stabilized’ at a level higher than the environmental standard: 55 mg l⁻¹. The goal of this paper is to examine causes of excessive nitrate leaching. This was done by relating measured nitrate concentrations with management characteristics such as N balances, cropping patterns and grazing intensities. Special attention was paid to aspects that were supposed to be conducive for leaching: crop rotation of grass and maize and grazing. No evidence was found for enhanced nitrate leaching due to the rotation of grass with maize compared to permanent cultivation. This could be ascribed to the reduction in fertilization levels in first and second year maize with 90 and 45 kg N ha⁻¹, respectively to account for the expected N release from the ploughed-in grass sod. Triticale was found to lead to higher leaching than grass or maize which is attributed to its poor growth in the period that it should function as catch crop in maize. Grazing contributed to a nitrate increase of about 30 mg NO₃⁻ l⁻¹ on grassland. As grazing management and intensity is already strictly optimized in order to restrict nitrate leaching, this result underpins the need to develop sustainable grazing methods on soil that is susceptible to nitrate leaching.     

Actualising (Overlooked) Material Capacities

An emphasis on material synthesis is not without its pitfalls and challenges. Here Branko Kolarevic , Professor and Chair in Integrated Design at the University of Calgary Faculty of Environmental Design, alerts us to the dangers of overlooking materials' shifting capacities, which are so often scale dependent, while also disregarding existing materials in favour of the new or novel. As the potential grows for material systems in buildings to become more adaptive and to harness automation, Kolarevic describes some exciting developments that are taking place in dynamic facade design, providing the much-heralded promise of an efficient use of ambient energy.