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121.
利用差示扫描量热仪、傅里叶红外光谱仪、广角X射线衍射仪研究了一种新型的以聚乙二醇为软段的聚氨酯相变储能材料。结果表明,当软段含量低于90%(质量分数,下同)时,即使温度高于聚乙二醇的熔点,此类材料仍不会熔化成液体,而表现出一种固-固相变行为。该聚氨酯储能材料相变焓较大,相变温度适中,且随着软段含量的减少,材料相变焓和相变温度呈递减趋势。其相变过程实质是聚氨酯软段聚乙二醇由结晶固态转变为无定形固态的过程。 相似文献
122.
The effects of washing with hydrogen peroxide (H2O2) and sodium hypochlorite (NaOCl) solutions on the gel-forming ability and physicochemical properties of surimi produced from bigeye snapper (Priacanthus tayenus), stored in ice for up to 14 days, were investigated. Generally, pH and the trichloroacetic acid (TCA)-soluble peptide content of washed mince varied, depending on the type of oxidizing agent and storage time of the fish. With increasing time of storage, the pHs of water- and H2O2-washed mince were lower than that of NaOCl-washed mince (P < 0.05). However, no differences in the TCA-soluble peptide contents of the resulting mince washed with any media were observed (P > 0.05). Washing with 20 ppm NaOCl resulted in the highest increase in both the breaking force and the deformation of mince from fish stored in ice for all the times studied (P < 0.05). Natural actomyosin (NAM) extracted from NaOCl-washed mince had higher surface hydrophobicity and disulfide bond (SS) content than that of water-washed mince (P < 0.05). With no effect on Ca2+-, Mg2+-, or Mg2+–Ca2+-ATPase activities, NaOCl washing resulted in an increase in Mg2+–EGTA-ATPase activity of NAM (P < 0.05). The results suggested that washing mince with the appropriate type and concentration of oxidizing agent can improve the gelling ability of surimi, particularly from low quality fish. 相似文献
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124.
Mostafa Moussaid Stphane Caillet Josphine Nketsia‐Tabiri Cheikh Boubekri Monique Lacroix 《Journal of the science of food and agriculture》2004,84(13):1657-1662
The study evaluated the effects of waxing, irradiation dose and post‐irradiation storage time on the essential oils in orange peel. Mature oranges (Maroc late) waxed or unwaxed were treated with 1 or 2 kGy radiation and stored for 9 weeks at 20 °C and 40–50% RH. Essential oils from the peel were extracted and analysed by GC. Results showed that D ‐limonene was significantly lower in waxed oranges; levels in samples treated with 2 kGy were higher than those in non‐irradiated or treated with 1 kGy. Linalool, methyl anthranilate and 3,7‐dimethyl‐2,6‐octadienal decreased as the dose increased. Levels of linalool increased with storage time but D ‐limonene was unaffected. These results may aid in guaranteeing the quality of orange essential oils during storage time. Copyright © 2004 Society of Chemical Industry 相似文献
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Shinichi Nomura Takushi Hagita Hiroaki Tsutsui Yoshihisa Sato Ryuichi Shimada 《Electrical Engineering in Japan》2008,164(2):37-43
The objective of this work is to discuss the concept of back‐to‐back interconnection systems with energy storage, especially with a Superconducting Magnetic Energy Storage (SMES) incorporated into a back‐to‐back DC link. In this case, each converter of the back‐to‐back system is used as a power conditioning system for the SMES coils. Since the AC–DC converter can be designed independently of the frequency of the power system, a two‐way switch is connected to the AC side of each converter. This two‐way switch can select the interconnected power systems. By using the two‐way switches, this system can provide the stored energy in the SMES system to each interconnected power system through two AC–DC converters. For instance, lower‐cost power of each power network can be stored through two converters during the off‐peak hours and made available for dispatch to each power network during periods of demand peak. Then this system increases the reliability of electric power networks and enables the economical operations depending on the power demand. This paper describes the unique operations of the back‐to‐back interconnection with SMES and discuses the optimal SMES configuration for a 300‐MW‐class back‐to‐back interconnection. © 2008 Wiley Periodicals, Inc. Electr Eng Jpn, 164(2): 37–43, 2008; Published online in Wiley InterScience ( www.interscience.wiley.com ). DOI 10.1002/eej.20482 相似文献
127.
文章在阐述我国石油价格形成机制的演变过程的基础上,针对我国目前石油定价机制所导致的诸如石油价格变动滞后以及由此带来的市场信号失灵等问题思考了相应的改革对策,提出了调整政府价格管理职能、建立平等竞争的市场规则、完善稳定油价的调控体系以及加快建立石油战略储备等7个方面的建议。 相似文献
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129.
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我国的西气东输工程从新疆塔里木油田到上海,管线长度达4000公里,为确保对长江三角洲地区安全稳定的供气,就必须在长江三角洲地区建设地下储气库,从而保证在管线故障期间应急供气,同时利用地下储气库调节冬季和夏季用气量的差异,保证长输管线的高效、平稳运行。在长江三角洲地区经地库址选择,目前准备将常州盆地的金坛盐矿用以建设地下储气库。盐穴地下储气库主要选择在盐层或盐兵上,利用水溶方式形成地下溶腔进行储气,选择合适的建库地址要结合地质、水、工程等诸多因素,造腔过程中需要采取一系列控制技术,在造腔过程中还要及时采取声纳测井技术进行跟踪监测,造腔过程的检测及腔体完成后的密封安全性检测是气库能否投入运行的关键。 相似文献
130.