Adsorption of H2S or SO2 on an activated carbon cloth modified by ammonia treatment

The aim of this research is to investigate how ammonia treatment of the surface can influence the activity of a viscose-based activated carbon cloth (ACC) for the oxidative retention of H₂S and SO₂ in humid air at 25 °C. Surface basic nitrogen groups were introduced either by treatment with ammonia/air at 300 °C or with ammonia/steam at 800 °C. The pore structure of the samples so prepared was examined by adsorption measurements. Changes in the surface chemistry were assessed by X-ray photoelectron spectroscopy, X-ray absorption spectroscopy and temperature programmed desorption (TPD). The change of ACC activity could not be merely attributed to surface nitrogen groups but to other changes in the support. Ammonia/steam treatment improved ACC performance the most, not only by introducing nitrogen surface groups, but also by extending the microporosity and by modifying the distribution of surface oxygen groups. Successive adsorption-regeneration cycles showed important differences between oxidative retention of H₂S and SO₂ and the subsequent catalyst/support regeneration process.     

Catalytic dehydrogenation of ethylbenzene with carbon dioxide: promotional effect of antimony in supported vanadium–antimony oxide catalyst

Alumina-supported vanadium oxide, VO_x/Al₂O₃, and binary vanadium–antimony oxides, VSbO_x/Al₂O₃, have been tested in the ethylbenzene dehydrogenation with carbon dioxide and characterized by S_BET, X-ray diffraction, X-ray photoelectron spectroscopy, hydrogen temperature-programmed reduction and CO₂ pulse methods. VSbO_x/Al₂O₃ exhibited enhanced catalytic activity and especially on-stream stability compared to VO_x/Al₂O₃ catalyst. Incorporation of antimony into VO_x/Al₂O₃ increased dispersion of active VO_x species, enhanced redox properties of the systems and formed a new mixed vanadium–antimony oxide phase in the most catalytically efficient V_0.43Sb_0.57O_x/Al₂O₃ system.     

The influence of silicon on carbon redistribution in steel weldments

Carbon redistribution was measured in ST1/ST2 Fe-2.5Si-0.8C/Fe-0.32Si-0.49C steel weldments in the temperature range 500–1000 °C. At the temperatures where austenite exists, carbon diffuses from ST1 into ST2; when ferrite is present, the diffusion flow reverses from ST2 into ST1. This effect is attributed to the degree of the silicon influence on the graphite precipitation and carbon activity in ST1 and ST2 steels. The opposite signs of the activity gradients in austenite and ferrite cause the reversal of the carbon diffusion when the annealing temperature is changed from the austenite to the ferrite temperature region. The carbon diffusion coefficients D_C and the thermodynamic interaction coefficients ε_C^Si in austenite have been assessed from the experimental data for ST1 and ST2 steels.     

Hierarchical Self‐Assembly of Peptide‐Coated Carbon Nanotubes

Numerous applications, from molecular electronics to super‐strong composites, have been suggested for carbon nanotubes. Despite this promise, difficulty in assembling raw carbon nanotubes into functional structures is a deterrent for applications. In contrast, biological materials have evolved to self‐assemble, and the lessons of their self‐assembly can be applied to synthetic materials such as carbon nanotubes. Here we show that single‐walled carbon nanotubes, coated with a designed amphiphilic peptide, can be assembled into ordered hierarchical structures. This novel methodology offers a new route for controlling the physical properties of nanotube systems at all length scales from the nano‐ to the macroscale. Moreover, this technique is not limited to assembling carbon nanotubes, and could be modified to serve as a general procedure for controllably assembling other nanostructures into functional materials.     

Policies to reduce energy use and carbon emissions in the UK

The UK differs from may other industrialized nations in that its carbon dioxide (CO₂) emissions from energy use have declined in recent years despite relatively rapid economic growth. In all sectors but transport, substantial reductions have already occurred in the level of carbon emissions per unit of GDP output. At the same time, a number of official and unofficial studies have pointed out that the UK has one of the largest remaining potentials amongst comparable industrialized countries for achieving further CO₂ reductions through the implementation of cost-effective energy efficiency and fuel switching measures. This paper discusses past and present patterns of energy use and carbons emissions in the UK. The analysis then examines historical trends in UK energy policy and presents policy options for further reducing the UK's energy-use and carbon emissions in the future.     

二氧化碳对油井水泥石的腐蚀及其防护措施

在湿环境下,油气构造中富含的CO_2对水泥石产生碳化腐蚀,碳化结果使水泥石渗透率变大、抗压强度减小,诱发流体窜流、塑性地层井壁垮塌等事故,造成巨大的经济损失。介绍了在不同温度下的水泥水化产物及其碳化产物。从化学角度分析了CO_2在不同温度下对油井水泥环碳化腐蚀的机理、影响因素及防护措施。在低于110℃的温室下,CO_2的腐蚀速度受扩散控制,其影响因素包括水泥浆密度和水泥石渗透率及水泥石孔隙液中Ca(OH)_2的含量,在水泥中掺加活性硅灰或提高水泥浆密度可预防碳化腐蚀。在大于110℃的高温下,碳化腐蚀速度受水泥水化产物中Ca(OH)_2含量和水泥石碳化后渗透率大小的影响。正确的防腐工艺是在水泥石中加入10％—15％的石英砂,或者在纯水泥中加3％—8％的膨润土。     

Long-term energy scenarios for Mexico: Policy options for carbon savings and main barriers

This paper shows that possibilities exist for maintaining current energy-related carbon emissions per capita in Mexico at almost constant levels in the long term. It is argued, however, that the identified carbon emissions reductions will not be achieved easily or rapidly, as they require a restructuring of Mexico's current technological base and an unusual degree of coordination among the government, lending institutions, equipment manufacturers, and final users. Such changes also will entail surmounting major institutional and financial barriers and creating a better international environment for technology transfer and capital lending.     

光纤模式噪声的研究

综述了光纤模式噪声的产生、计算，并介绍了减小它的一些方法。