纳米加工和纳米电子器件

介绍了电子束曝光技术、EUV光刻技术和X射线光刻技术的进展;对各种纳米电子器件如单电子器件、共振隧穿器件和分子电子器件的研究现状及面临的主要挑战进行了讨论。     

Global experience curves for wind farms

In order to forecast the technological development and cost of wind turbines and the production costs of wind electricity, frequent use is made of the so-called experience curve concept. Experience curves of wind turbines are generally based on data describing the development of national markets, which cause a number of problems when applied for global assessments. To analyze global wind energy price development more adequately, we compose a global experience curve. First, underlying factors for past and potential future price reductions of wind turbines are analyzed. Also possible implications and pitfalls when applying the experience curve methodology are assessed. Second, we present and discuss a new approach of establishing a global experience curve and thus a global progress ratio for the investment cost of wind farms. Results show that global progress ratios for wind farms may lie between 77% and 85% (with an average of 81%), which is significantly more optimistic than progress ratios applied in most current scenario studies and integrated assessment models. While the findings are based on a limited amount of data, they may indicate faster price reduction opportunities than so far assumed. With this global experience curve we aim to improve the reliability of describing the speed with which global costs of wind power may decline.     

Plastic collapse of pipe bends under combined internal pressure and in-plane bending

Plastic collapse of pipe bends with attached straight pipes under combined internal pressure and in-plane closing moment is investigated by elastic–plastic finite element analysis. Three load histories are investigated, proportional loading, sequential pressure–moment loading and sequential moment–pressure loading. Three categories of ductile failure load are defined: limit load, plastic load (with associated criteria of collapse) and instability loads. The results show that theoretical limit analysis is not conservative for all the load combinations considered. The calculated plastic load is dependent on the plastic collapse criteria used. The plastic instability load gives an objective measure of failure and accounts for the effects of large deformations. The proportional and pressure–moment load cases exhibit significant geometric strengthening, whereas the moment–pressure load case exhibits significant geometric weakening.     

水分对高碱值硫化烷基酚钙结构和清净性的影响

采用傅立叶红外光谱仪，分析了水分对清净剂高碱值硫化烷基酚钙结构组成的影响；采用热管氧化试验法和曲轴箱模拟试验法，考察了高碱值硫化烷基酚钙在加水前后清净性能的变化；采用四球试验机和高频往复试验机，分析了水分对高碱值硫化烷基酚钙润滑性能的影响。结果表明，油中的水含量对高碱值硫化烷基酚钙的水解安定性能影响较大，并且随着水含量的增加，油品的清净性能和抗磨性能变差。     

Morphology/behaviour relationship of nanocomposites based on natural rubber/epoxidized natural rubber blends

In order to analyze the effect of an epoxidized natural rubber (ENR) and filler treatment on the morphology and behavior of natural rubber (NR) nanocomposites, blends of these polymers have been prepared. The nature and extent of the clay dispersions in the filled samples were evaluated by X-ray diffraction. In the presence of ENR, an exfoliated structure was obtained which suggests that enough rubbery polymer was incorporated into the interlayer spacing. The effect of clay in rubber compounds was analyzed through rheological, mechanical and swelling characterization. A sensible improvement in the nanocomposite properties was observed by the addition of organoclay. It has been deduced that the properties of the compounds strongly depend on the extent of the silicate nanolayers dispersion into the rubber matrices as well as on the organoclay type and elastomer compatibility.     

A Golden Section approach to optimization of automotive friction materials

A Golden Section approach combined with relational grade analysis is proposed as an experimental design tool helpful in the development of new automotive friction materials. Golden Section was used to design the volume fraction of the components systematically. The changes in friction performance (friction coefficient and wear) measured using Friction Assessment and Screening Test (FAST) can be correlated with component variations by use of relational grade analysis. This approach was utilized to optimize a non-metallic friction material containing seven ingredients including two fibers (aramid and slag fiber), four fillers (Al₂O₃, BaSO₄, graphite and nitrile rubber) and one binder (benzoxazine). The volume fraction of seven components was varied simultaneously in order to optimize the parameters of friction coefficient and wear with a minimum number of tests. Three phases were performed to find the optimal proportion of the components. The optimized friction performance was obtained after doing 19 formulation experiments.     

Aroused problems in the deposition of diamond-like carbon films by using the liquid phase electrodeposition technique

Hydrogenated diamond-like carbon (DLC) films were prepared by using liquid phase electrodeposition technique. The effects of the applied potential and the carbon sources on the deposition process and film structures were studied. It has been found that the organic liquids with high dielectric constants, small viscosities and the methyl group bonding to the polar group are appropriate carbon sources. The increasing of potential improves the formation of sp³ carbon during the deposition process. In a high electric field, organic molecules are polarized and reacted on the surface of the electrode, turning out DLC and other products. It is believed that the reaction follows a polarization-reaction mechanism.     

Preparation of ultra-fine polyimide fibers containing silver nanoparticles via in situ technique

Ultra-fine polyimide fibers containing silver nanoparticles were prepared by electrospinning from poly(amic acid)/(trifluoroacetylacetonoto)silver(I) (PAA/AgTFA) solution. Thermal curing of the silver(I)-containing fibers led to cycloimidization of the poly(amic acid) into polyimide with concomitant silver(I) reduction. The polyimide–silver fibers were characterized by FT-IR, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The average diameters of silver nanoparticles and ultra-fine PI fibers electrospun from solutions with different amounts of AgTFA were studied, and the crystal structure of silver nanoparticles was also presented.     

不同类型在役抽油机机架受力分析

通过现场测试和检查,对油田特定区域内经过优化后的各种不同类型抽油机在额定载荷下的支架以及连杆受力情况进行了分析和评价。为在油田范围内进行机采设备的选型和推广提供一些参考。