旋光法测定盐酸青藤碱的含量

目的 :建立测定盐酸青藤碱含量的方法 .方法 :采用旋光法 .结果 :浓度在 10～ 50mg·L- 1范围内α～C线性关系良好 ,平均回收率为 99.96% ,RSD为 0 .19% ,与非水滴定法测定结果相符合 .结论 :本法简易 ,快速 ,准确 ,适用于盐酸青藤碱原料药分析     

淀粉水解最佳酸度的探究

人教版新教材《化学与生活》在“生命的基础能源——糖类”一节中,通过实验探究淀粉的水解。其中实验步骤1为：“在试管1中加入0．Sg淀粉和4mL水,     

淀粉水解实验条件的探讨

淀粉水解反应是中学化学教学中演示多糖性质的一个实验,主要说明多糖水解后可生成葡萄糖,并证明葡萄糖的还原作用,实际上淀粉水解的条件不仅仅限于酸催化水解,那么在哪种条件下水解的效果最好,最适宜于进行学生或演示实验,这里可以用正     

用生活中的物质探究淀粉的水解

淀粉是生活中常见的物质,是食物的重要组成成分.本文用土豆、山芋、藕、浓米汤、浓面汤等作为淀粉的来源,探究了催化剂、温度等条件对淀粉水解结果的影响,既培养了学生的探究能力,也加强了化学与生活的联系.     

马铃薯交联淀粉的性能分析

对以六偏磷酸钠为交联剂制备得到的马铃薯交联淀粉的基本性能指标进行分析。试验结果表明：马铃薯淀粉经过交联后,沉降积由3．89mL降至2．32mL,冻融析水率由25．40％降至8．18％,抗老化性提高21．1％,热稳定性提高81．7％,耐酸碱性能明显增强。马铃薯交联淀粉在食品工业中具有更大的应用空间。     

用正交法探究几种因素对淀粉水解的影响

中学化学实验研究的目的主要是发挥实验的教学功能,提高化学教学质量。淀粉的水解实验在苏教版多本化学教材中都出现了,但是每本教材中对淀粉水解实验的操作试剂及条件控制有些不同。本文运用正交试验法对淀粉水解最佳试剂及反应条件进行实验探究。     

水解红薯淀粉酸奶工艺的研制

以红薯,鲜牛乳为主要原料,采用酶法糖化工艺水解红薯淀粉,选取嗜热链球菌和保加利亚杆菌１：１的混合菌种为发酵剂进行乳酸发酵,以Ｌ９（３＾４）正交试验得出最佳配料组合。结果表明：以红薯糖浆５％、鲜牛奶５０％的混合液,再添加６％的蔗糖、接种量为３％制成的红薯乳酸饮料滋味独特,香气浓郁怡人,具有较高的营养价值,口感好,价格低廉。     

Hydrolysis of Raw Corn Starch Granules by Glucoamylase and Product Inhibition During the Hydrolysis

Raw corn starch granules were hydrolysized by glucoamylase in a chemostat. The hydrolysis of three different-sized granules shows that smaller granules undergo more hydrolyzation than larger ones. After 78 h, 97% of the granules was hydrolysized with diameter between 0.15 mm and 0.3 mm at 50℃. When corn starch concentration increased from 100 g/L to 250 g/L, the amount of reducing sugar produced was proportional to the initial substrate concentration and no substrate inhibition phenomenon appeared. In order to study the product inhibition exactly, the product from hydrolysis reaction itself was added into the hydrolysis system at the beginning of starch hydrolysis.Product inhibition with different quantities of product added were studied in the initial several hours,during which period enzyme inactivation could be neglected and product inhibition could be studied separately. The experiments indicate that product inhibition happens when the additional quantity exceeds 9.56 g/L.     

生物接触氧化法深度处理定西市马铃薯淀粉加工废水

采用生物接触氧化作为深度处理工艺,进一步去除前期厌氧工艺出水中的有机物。结果表明：在DO＝4 mg／L、HRT＝6 h的最佳工艺条件下,生物接触氧化反应器对厌氧工艺处理后的马铃薯淀粉加工废水有着较好的处理效果,出水COD＜85 mg／L、BOD＜5 mg／L、SS＜35 mg／L、pH 6～pH 9,达到《污水综合排放标准》（GB8978—1996）二级排放标准。     

改性淀粉絮凝剂处理含油废水的试验效果

通过将玉米淀粉与氢氧化钠、三氯化铝和无水碳酸钠在恒温磁力搅拌器上搅拌、加热,使得玉米淀粉改性,制得改性淀粉絮凝剂,并研究了改性淀粉絮凝剂对含油废水的处理效果.试验结果显示,在搅拌速度与时间分别为快搅速度200 r/min,快搅时间0.5 min;慢搅速度100 r/min,慢搅时间3 min的情况下,使用改性淀粉絮凝剂处理含油废水时,COD去除率为77.94%、石油类去除率为61.2%、透光率为62.7%、SS去除率为79.96%;最佳反应条件为:投药量为12 mg/L、温度为5~30℃、pH值为6-8.     

大米中淀粉含量测定探究

通过研究大米淀粉的酶解条件,比较了Seavg法和盐析法这两种除蛋白方式对测定大米淀粉含量的影响,并用旋光法测定了大米淀粉含量,得到了一种快速、经济、结果重现性好的测定大米淀粉含量的方法。     

酸变性微孔淀粉的制备工艺研究

微孔淀粉是具有重大应用价值的新型变性淀粉,根据淀粉酸变性的反应机理,采用一次回归正交试验,研究了硫酸用量、反应温度、反应时间、尿素用量等因素对酸变性微孔淀粉性能的影响,并用红外光谱对产品的结构进行了表征。以产品对酶变性微孔淀粉样品的流度偏差为指标,得到了酸法制备微孔淀粉的最优化工艺条件：5％的稀硫酸用量为2mL/g淀粉,反应温度为40℃,反应时间为4h,尿素用量为0．75g／g淀粉。     

基于主从递阶博弈的建设项目最优工期决定

建设项目工期的最优确定与控制问题一直是项目管理理论和实践工作者十分关注的课题之一。当业主（即发包商）利用奖惩手段激励承包商压缩工期时,业主和承包商就成为工期决策博弈的参与者,奖惩激励的优化问题就是一个完美信息下的二层主从递阶博弈问题。在此基础之上,文章引入政府作为社会规制者,并利用数学方法,最终揭示了在建设工程实践当中,政府综合运用立法行为、行政干预等手段限制招投标和项目合同中的业主垄断行为这一现象所蕴含的重大理论背景。     

关于双积分系统时间最优控制中最优时间的计算方法的推导过程

本讨论了利用极小值原理设计的双积分系统的时间最优控制的控制曲线和开关曲线，着重讨论了该系统在最优控制下最优时间的计算方法的推导过程。     

The Optimal Immersion Time to Second Language Community

When to immerge students in the target language community is a hot issue debated by many researchers through the whole linguistic and second language research history. While as far as my hypothesis con...     

The Optimal Immersion Time to Second Language Community

When to immerge students in the target language community is a hot issue debated by many researchers through the whole linguistic and second language research history.While as far as my hypothesis concerned,I argue that it’s a better way for second language learners to learn some basic language skills before getting involved in that language community,including the target culture,fundamental second language skills,and first language abilities.Meanwhile,I demonstrate my argument from four aspects:age factors,first language factors,cultural factors and motivational factors.And I argue that English learners receive late immersion perform as well as or better than children in early immersion programs,since there is a direct relationship between native language and second language learning.As long as second language learners are literate in their first language,then their abilities in first language can facilitate the second language learning and can discipline themselves in the process of how to learn a second language.Meanwhile,transmitting cultural knowledge plays an important role in second language learning,and the most suitable approach is to do preparing transmission before students entering the real cultural community,i.e.the preparing work should be done before students getting involved in the language community;otherwise they may catch the cultural shock and are reluctant to explore the target culture.This paper aims at finding a most comfortable and preferable environment for learners to learn a second language and providing parents who are planning to send their children abroad some feasible advice.