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51.
Maltose long-chain fatty acid esters (MFAE), esterified at the 6 and 6′ position, were synthesized with stearic, palmitic, myristic, and oleic groups. Synthesis yields were 15–20% based on initial maltose present, and structural confirmation was obtained using plasma desorption mass spectrometry and nuclear magnetic resonance spectroscopy. These surfactants have surface tensions in the range of 34–36 dyn/cm at their critical micelle concentrations (CMC) of approximately 10−5–10−6 mol/L. The increased chain lengths have a marked effect, reducing CMC values for MFAE by approximately three orders of magnitude over similar carbohydrate-based dodecyl chain sources. Within chain lengths between 14 and 18 carbons, the rate of change in CMC is significant and decreases with increasing chain length for MFAE. The melting points of MFAE are approximately 40°C, and the heat capacities range from 1.6 to 1.9 J/g·K. These numbers are comparable to those of sucrose esters, indicating their applicability in similar uses. However, because MFAE, unlike sucrose, possess an anomeric carbohydrate carbon position, these surfactants maintain their reducing nature and are susceptible to further derivatization. They are also synthesized from renewable, economical carbohydrates and lipids and may provide an excellent alternative to pertrochemical-derived products.  相似文献   
52.
介绍了15kt/a本体苯乙烯-丙烯腈(SAN)装置试生产打火机专用SAN树脂的生产情况,确定了主要工艺配方及参数:进料组成为乙苯浓度为6%-11%、丙烯腈浓度为30%-42%,聚合温度130-145℃、压力0.40-0.46MPa,搅拌转速60-90r/min,脱挥温度215-250℃、压力小于等于4kPa;并对影响打火机志用SAN树脂性能的主要工艺条件及因素进行了讨论。结果表明,聚合温度、结合丙烯腈含量、熔体流动指数、转化率是影响打火机专用SAN树脂生产工艺及产品性能的主要因素。  相似文献   
53.
开发了一种用于布朗扩散型纤维除雾器的便携式现场测试装置,用这套装置可在现场测定纤维床阻力,从而对元件制造水平进行评价和比较,或在维修期间预测清洗后元件的操作性能。介绍便携式现场测试装置的设备布局、安装和运行,并对整体充填、平行缠绕、斜交叉缠绕纤维床及同心组合纤维床进行比较。此外,论述了硫酸装置工艺气体压降的价值。  相似文献   
54.
55.
Various plant secondary metabolites related to cinnamic acid are of interest because of their repellency to birds and their occurrence in ecologically important food items. Coniferyl benzoate (CB), a phenylpropanoid ester that occurs in quaking aspen (Populus tremuloides) is of particular ecological interest because of its effect on ruffed grouse (Bonasa umbellus) feeding behavior and its possible influence on the population dynamics of this bird. During detoxification processes, CB and other analogous compounds are metabolized into by-products, such as ferulic acid (FA), that can cause anti-reproductive effects. We tested whether consumption of CB produces antire-productive effects similar to FA using male and female Japanese quail (Coturnix coturnix) as avian models for ruffed grouse. The parameters we investigated included: the production, morphology, and development of eggs; reproductive characteristics influenced by estrogen; serum prolactin levels; and male reproductive behavior. Dietary CB did not produce antireproductive effects similar to FA at intake levels that Japanese quail and ruffed grouse would freely consume. Consumption of CB by Japanese quail significantly reduced egg production and body mass but did not affect male reproductive performance. Coniferyl benzoate's effect on egg production may be explained by lower energy acquisition and retention rather than endocrine changes per se. Contrary to previous reports, it is unlikely that FA, or similar compounds act directly as estrogen mimics or antagonists. Although, CB did reduce egg production in quail, it is unlikely that it would affect egg production in wild ruffed grouse. Detoxification costs and the effects of CB on nutrient utilization may explain why ruffed grouse avoid high dietary levels of CB.  相似文献   
56.
李圣华 《炭素技术》2006,25(2):49-55
针对炭素制品生产过程产生的粉尘、沥青烟气、噪声等主要涉及工业卫生及环境保护等方面的问题进行剖析,并对治理方法做了简要的介绍。  相似文献   
57.
介绍了采用热管锅炉回收硫酸系统电除尘器出口烟气废热情况,可回收废热生产0.8MPa饱和蒸汽1.0t/h。通过严格控制饱和蒸汽压力、炉气的三氧化硫含量及入炉原料的水分含量,热管锅炉连续运行两年未发生泄漏。运行一年即可收回成本,经济效益显著。  相似文献   
58.
聚丁二烯和聚异戊二烯橡胶的长链支化   总被引:1,自引:1,他引:1  
  相似文献   
59.
沈长文 《大氮肥》2006,29(1):48-49
介绍自密封阀的密封原理及其在氨汽提尿素装置中的应用,对其长期运行中出现的泄漏及泄漏原因进行分析,根据不同的泄漏方式分别提出了现场维修的方法.  相似文献   
60.
In pot and field experiments conducted in 1990 and 1991 on an acid sandy, phosphorus (P) deficient soil in Niger, West Africa, the effect of seed coating on seedling emergence, early growth and grain yield of pearl millet (Pennisetum glaucum (L.) R. Br.) was studied. Seeds of pearl millet were coated with different rates (0; 0.5; 1.0; 2.0; 5.0; 10.0 mg P seed–1) and types of P fertilizers (single superphosphate, ammonium dihydrogen phosphate; monocalcium phosphate, sodium dihydrogen phosphate and sodium triphosphate). Seedling emergence was generally reduced at coating rates higher than 0.5 mg P seed–1 and prevented with single superphosphate and sodium triphosphate at rates higher than 5 mg P seed–1. No correlation was found between the pH and osmomolity of the coatings and final emergence of millet seedlings. The most favourable effect on plant growth and P content was achieved with ammonium dihydrogen phosphate (AHP) as seed coating. This was attributed to the enhancement effect of ammonium on P uptake. Compared to the untreated control dry matter production at 20 days after planting (DAP) was increased by 280%, P content per plant by 330%, total biomass at maturity by 30% and grain yield by 45%. Although seed coating with AHP may be harmful to seedlings emergence, it represents a suitable method to enhance early growth and increase yield of pearl millet.  相似文献   
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