利用大孔树脂吸附提取桑黄总黄酮

利用几种大孔树脂对桑黄黄酮的吸附与解吸性能进行了比较筛选实验。结果表明，样品浓度、吸附时间和解吸时间等因素都会对提取效果有影响。通过比较发现树脂DM301比较适合于吸附提取桑黄总黄酮。应用DM301型大孔树脂，样品液的体积与树脂量比为（2—3）：1（mL：g），黄酮浓度为2mg／mL，吸附时间为14h，用3倍于样品液体积的60％乙醇解吸5h可以得到比较理想的提取结果，平均回收率为95．2％。     

2种浸渍胶膜纸饰面人造板甲醛释放量研究

采用1 m3气候箱法测试2种浸渍胶膜纸饰面人造板甲醛释放规律以及不同处理条件对板材甲醛释放浓度的影响。结果表明,热压工艺、基材结构可能是影响甲醛释放周期的关键因素,2种饰面人造板的平衡周期基本相同;封边处理可有效降低甲醛含量得释放;温度和相对湿度与板材甲醛释放量呈正相关,空气交换率与板材甲醛释放量呈负相关。     

灰枣多糖大孔径树脂提纯工艺优化

新郑灰枣富含各种营养成分,特别是多糖具有抗氧化抗癌等许多生物效应。为研究新郑灰枣多糖的提纯工艺,该文在超声波酶法联合提取、乙醇沉淀、超滤膜过滤得到的粗多糖的基础上,筛选出的AB-8大孔树脂纯化多糖,并对树脂的动态吸附解吸特性进行研究。响应曲面法优化AB-8大孔树脂动态吸附工艺条件,最佳动态吸附条件为:上样速率1.5mL/min,料液浓度2.2mg/mL,pH值5.6,最大动态吸附量为19.52mg/g;正交试验优化AB-8大孔树脂动态解吸的最佳工艺条件为:氯化钠浓度为0.4mol/L,乙醇添加量60%,盐酸浓度0.2mol/L,流速1.5mL/min,最优动态解吸率为85.21%。通过树脂纯化,多糖纯度可达88.87%。该红枣多糖提纯技术是一种非常有效的方法,在医疗及保健行业具有巨大的应用潜力和市场。     

Effect of the Extraction Period on the Routine Assessment of Soil P Status by Ion‐Exchange Resin Membranes

The cation–anion exchange resin membrane (CAERM) system is one of the most promising alternative methodologies for the assessment of soil phosphorus (P) availability. Nevertheless, the CAERM method has a recommended period of extraction (16 h) that limits its applicability. With the aim to improve the use of CAERM in routine laboratory work, seven extraction times were studied and compared for repeatability and biological accuracy, using 150 samples of soils and covering a wide range of properties. The results showed dissimilar quantities of extractable P, according to the nature of soils and the period of extraction time. On average of all soils, values of extractable P ranged from a 2.4 mg kg^?1 and 26.7 mg kg^?1 in 0.25‐h and 16‐h extraction times, respectively. Relative to the repeatability aspects, the results reveal a tendency of increasing results with the decrease of the period of extraction, showing coefficient variation (CV) values ranging from 5% (16 h) to 14% (0.25 h). All the extraction periods tested for the CAERM presented highly significant values of r (0.824–0.943) between extractable P and each of the three biological parameters: relative yield of ryegrass, P content, and P uptake. Considering the three biological parameters simultaneously, the best results were obtained for extraction periods of 8 h, 2 h, and 4 h. Based on the results, and considering both practical and accuracy aspects, it is conclude that 2 h of extraction is a valid alternative to the 16‐h standard extraction period for the CAERM methodology.     

Diversity,regeneration status and population structure of gum- and resin-bearing woody species in south Omo zone,southern Ethiopia

South Omo Administrative Zone in Ethiopia is home to 18 indigenous ethnic groups whose livelihood is vulnerable due to recurrent drought and degradation. Despite the preliminary observation showing the rich dry-forest resource base that, if sustainably managed could enhance livelihoods and biodiversity conservation, there is lack of empirical data on its current status. We conducted a study aiming at quantifying the population status of gum- and resin-bearing species in two randomly selected districts, Hamer and Bena-Tsemay. Seventy-five quadrats(35 at Hamer and 40 at Bena-Tsemay) each measuring 400 m2 were established along line transects to assess species diversity and equitability, density, frequency, dominance, importance value and population structure. We recorded a total of 27 woody species of 12 families and 14 genera. Fifteen species(9 at Hamer and 14 at Bena-Tsemay) of the genera Acacia, Boswellia, Commiphora and Sterculia, were identified as either major sources of commercial gums and resins or their adulterants. Gum- and resin-bearing species comprised 56% and 57% of species richness, 48% and 50% of total density per ha, 95% and 98% of basal area, and 64% and 56% of importance values at Hamer and Bena-Tsemay, respectively. Diversity of the entire woody species assemblage and of the gum- and resin-bearing species was slightly higher at Bena-Tsemay(H= 2.61, 1.4) than at Hamer(H′= 2.48, 1.28), respectively. The diversity and abundance of the resource base suggest potential for development of value-added commercialization of gum and resins to enhance livelihoods and encourage sustainable management of the forest at these study areas. We recorded, however, declining natural regeneration of most gum- and resin-bearing species, and this calls for integrated and participatory species management and landscape rehabilitation.     

果胶生产中有关化学问题的探讨

本文简述了离子交换树脂法生产果胶的工艺流程,着重讨论了用此法生产果胶中的有关化学问题。     

萜烯树指及其在压敏胶粘剂中的应用

本文对萜烯树脂生产和研究的基本情况及在压敏胶中的应用作了综述性报道     

Analysis of phenol-resorcinol-formaldehyde resins

A method based on high-performance liquid chromatography (HPLC) and proton magnetic resonance (PMR) spectroscopy for analyzing phenol-resorcinolformaldehyde (PRF) resins is reported. The equations that describe the number-averaged structures of PRF resins in terms of the PMR absorption intensities of acetylated resins have been derived on the basis of the work of Woodbrey et al. and Anderson et al. The P/R molar ratio of the resin calculated from the PMR intensities was in good agreement with the synthetic P/R molar ratio when correction was made for the loss of phenol evaporated during the drying process that preceded the acetylation. The number-averaged molecular weight (M_n) of the acetylated resin calculated from the PMR intensities agreed with the M_n determined by cryoscopy. Unreacted phenol and resorcinol could be determined by analyzing the water-soluble fraction of the resin by use of high-performance liquid chromatography.Part of this paper was presented at the 4th annual meeting of the Kyushu branch of the Japan Wood Research Society, Miyazaki, November 1997, and at the 48th annual meeting of the Japan Wood Research Society, Shizuoka, April 1998     

脲醛树脂结构研究进展

在过去的２０余年里,为获得结构更合理、性能更优异的脲醛树脂,人们使用近代分析手段对脲醛树脂结构进行了广泛的研究,付立叶变换红外光谱（ＦＴＩＲ）和１３Ｃ核磁共振（１３ＣＮＭＲ）是目前脲醛树脂结构研究的最主要方法,其中１３ＣＮＭＲ是在分子水平描述脲醛树脂结构的最完善、最有效的工具。本文综述近２０年脲醛树脂结构研究进展,内容包括结构研究方法、内容和结果。     

单根阴离子交换柱法提取L-谷氨酰胺工艺研究

[目的]研究不同影响因素及工艺条件对提取L-谷氨酰胺的影响,为谷氨酰胺的工业化生产提供一种新型分离工艺。[方法]利用单根阴离子交换柱,采用静态吸附试验和动态分离试验研究从酶法合成液中提取谷氨酰胺的各种条件。[结果]模拟液离交分析的最适条件为：树脂201x4,进样流速为3．0BV／h,进样pH值6．5,谷氨酸浓度1．O％。酶反应液处理的工艺条件为：脱色温度40℃,pH值6．5,10．0g/L粉末状活性炭进行二次脱色,15．0mmol／L的Ca2＋添加量来去除样液中PO4^3＋,离交分离条件同模拟液。Gin收率为66．6％、Glu去除率为95．O％。[结论]该研究得到的处理方法简单易行,Gin收率和Glu去除率高,在工业生产中有较好的应用前景。