ترجمه مقاله نقش ضروری ارتباطات 6G با چشم انداز صنعت 4.0
- مبلغ: ۸۶,۰۰۰ تومان
ترجمه مقاله پایداری توسعه شهری، تعدیل ساختار صنعتی و کارایی کاربری زمین
- مبلغ: ۹۱,۰۰۰ تومان
First extraction of the dewaxed rice straw with 1% NaOH at 558C for 2 h and then following treatment with 0.0, 0.5, 1.0, 2.0, 3.0, 4.0 and 5.0% hydrogen peroxide at 458C for 12 h at pH 11.5 solubilized 67.2, 77.2, 78.7, 83.7, 85.5, 87.3 and 88.5% of the original hemicelluloses, and 2.5, 9.8, 11.8, 12.1, 15.6, 16.4 and 17.8% of the original cellulose, respectively. Meanwhile, the two-stage treatment together resulted in a dissolution of 68.3, 85.4, 89.4, 92.7, 92.7, 94.3 and 95.1% of the original lignin under the conditions given, respectively. Comparison of these hemicellulosic preparations indicated that alkali treatment in the absence of H2O2 favoured solubilization of the small molecular size of hemicelluloses, which are rich in glucose, probably originating from a-glucan, while the second stage treatment by alkaline peroxide enhanced dissolution of larger molecular size hemicelluloses, which are rich in xylose, principally resulting from l-arabino-(4-O-methyld-glucurono)-d-xylan. The treatment by alkaline peroxide under the conditions used did not affect the overall structure of macromolecular hemicelluloses except for a noticeable degradation of cellulose and hemicelluloses during the treatment with more than 1.0% H2O2. q 2000 Elsevier Science Ltd. All rights reserved.