Esterification of Acrylic Acid with 1,4‐Butanediol in a Batch Distillation Column Reactor over Amberlyst 15 Catalyst

The esterification reaction of acrylic acid (AA) with 1,4‐butanediol (BD) to produce 4‐hydroxybutyl acrylate (HBA) was carried out in a batch reactive distillation mode over the Amberlyst 15 catalyst. The reactive distillation was highly desirable to increase the reaction rate of BD and eventually to obtain the high purity of HBA because the unreacted BD was not easily separable to the produced HBA after the reaction. The reaction pressure below 760 mm Hg was used to remove the by‐product water from the reaction zone. The air‐bubbling operation was successfully applied to prevent the polymerization of reactants and products under the vacuum condition (400 ～ 760 mm Hg). The reaction rates were strongly dependent on the reaction pressure, especially, the reaction rate of BD disappearance. The increased reaction rate of BD by the reactive distillation enabled to produce a high purity of HBA.     

BD/EG组分变化对共聚酯结构及其纤维性能的影响

采用DMT与BD、EG共缩聚的方法制取的共聚酯是无规共聚酯。共聚酯的Tg、Tc、Tm、Xc％随BD/EG组分不同而异。BD/EG组分变化影响纤维的力学性能及热性能。根据纤维性能要求,控制BD/EG含量,可获得常压沸染、富有弹性、热稳定性良好、手感柔软、丰实的纤维。若引进第四单体,其性能更接近羊毛,具有良好的毛型效果。     

企业多角化经营战略研究

系统地研究了企业多角化经营战略在世界范围内的发展过程和产生的原因，从多个角度对企业多角化经营战略进行了系统的分类，并深入分析了影响企业选择多角化经营战略的因素     

Sickle bush (Dichrostachys cinerea L.) field performance and physical–chemical property assessment for energy purposes

The sickle bush (Dichrostachys cinerea (L.) Wight & Arn.) comprises a woody legume shrub which is widely distributed throughout of the tropical areas of Africa, Asia and Oceania, being found as well in Cuba where it represents a difficult to control invasive plant. It holds great silvopasture and energy crop potentials. In southwestern Spain a two year field trial was conducted contemplating also another six hardwood taxa commonly used as energy crops. The sickle bush above ground dry biomass fraction was 60.4%; sickle bush displayed a high transpiration rate during hot days (3.02 kg m⁻² d⁻¹ to 6.82 kg m⁻² d⁻¹); cold winter temperatures (<−2 °C) together with hot and dry summer air (<20% relative humidity) committed survival and growth. The physical-chemical wood properties and the pellets thereof derived were analyzed and compared to those of the other energy crop taxa. The within other woody species normal chemical composition range coupled to a high wood density and energetic use properties (19.2 MJ kg⁻¹ higher heating value, 29 g kg⁻¹ ash content) all allow for an industrial use. Pellets evidenced also good physical and mechanical properties (690 kg m⁻³ bulk density, 42 g kg⁻¹ moisture content). However, the mechanical durability (93.9%) was slightly less than that required by the non-industrial use standards, therefore further improvements should be studied. All of the above could encourage scrubland cuts in Cuba as a mechanical control method, in addition to the expansion of plantations within of their tropical climate based natural habitats.     

The 2013 reforms of the Flemish renewable electricity support: Missed opportunities

The Flemish renewable electricity support system has struggled to address a number of problematic issues in the past. These included excessive profit margins and general malfunctioning of the green certificate market, as well as a lack of qualification of various existing renewable energy technologies. The Flemish government responded to these issues by introducing major reforms in 2013, including “banding” to differentiate the support for various technologies. However, reliable methods for differentiating renewable electricity technologies and calculating support levels have not been sufficiently developed. The main objective of the 2013 reforms was to reduce support costs, but application of German feed-in tariffs on 18 reference technologies has shown that most projects in Flanders continue to receive high levels of support. The 2013 reforms did not succeed in addressing malfunctioning of the green certificate market. On the contrary, the confidence of investors in renewable electricity plants has decreased as the terms of support can be altered retroactively by adjusting remuneration levels and through political interventions. Future adaptations are likely to be made which will further decrease the overall stability and effectiveness of the system.     

A study on UV-curable coatings for HD-DVD: Primer and top coats

This study relates to the development of coatings for optical discs in high-density digital versatile disc systems (HD-DVD or blue lay disk) that use a high numerical aperture of 0.85 at 405 nm wavelength and have a protective top layer over a primer layer for protection against damage and dust. Ultraviolet-curable raw materials of two acrylic monofunctional monomers ( isobornylacrylate, IBA and tetrahydrofurfurylacrylate, THFA) and two kinds of urethaneacrylate oligomers (OUMD and OUME) have been easily mixed with photoinitiators. Curing rate of these materials was characterized by FT-IR. In case of top coats, VTES (vinyltriethoxysilane) and acrylic acid were added to enhance the abrasion resistance. These two kinds of UV-curable resinous materials having no solvent were synthesized and investigated as means for making a blue ray disk having good optical and mechanical properties. In addition, dynamic characteristics including reflectivity, fluctuation of RF signal and noise level were also investigated.     

BD600延时器的原理及使用

简要介超数字音频延时器的工作原理,以及BD600延时器的安装、调试、设置、按钮基本功能及具体使用方法。     

Malta: housing and real estate, 1980–2005

Over the past two decades, private house ownership has expanded exponentially throughout Europe. Over the past decade, this has intensified with the desire and ability among wealthier northern Europeans to own second homes in sunnier climes. It has not only driven up house prices in pockets of Europe, but has also impacted on the social and cultural lives of local communities in ‘desirable locations’, having an adverse effect on the quality of the built environment. Lino Bianco describes the situation in Malta and how, after decades of largely uncontrolled development by real-estate investors, the government is taking stock and encouraging through investment in architectural education, and property legislation, the growth of an indigenous architecture that is contextual, sensitive and energy-conscious. Copyright © 2006 John Wiley & Sons, Ltd.     

基于SX52BD的嵌入式Web服务器的设计与实现

讨论和比较了嵌入式系统Internet接入的几种方法,并给出了一种基于SX52BD微控制器的实现方案,并详细介绍了硬件接口电路以及相关的软件实现。     

Influence of weave of carbon fabric on abrasive wear performance of polyetherimide composites

Three composites of Polyetherimide (PEI) reinforced with carbon fabric (CF) of three weaves viz. plain, twill and satin-4 H were developed keeping the amount of fabric constant (55% by vol.). Studies on mechanical properties confirmed that the twill weave composite (T) showed the highest strength, modulus (both tensile and flexural) and interlaminar shear strength (ILSS) followed by satin (S) and plain weave (P) composites. The performance order, however, was reverse in the case of toughness and elongation to break. Specific wear rate in a single-pass, unidirectional and un-lubricated abrasive wear mode against SiC paper showed strong influence of weave in mild wear condition (load 10 N). Composite S showed the highest wear resistance (W _R) followed by composites T and P. With increase in load, the difference in performance diminished to the extent that at 40 N, it was almost similar for all the three composites. This was correlated with the difference in the length of the fibers between crossover points which, in turn, allowed the microdisplacement of fibers in the composites during abrasion. This was supported by the SEM.