沙漠水科学材料研究综述

沙漠化地区的生态恢复是一个世界性难题,植被恢复是最可持续的方法,但植被恢复面临着科学用水的挑战,科学用水最有效的方法是引入新材料技术。综合分析了近年来出现的水科学材料的原理和特点,包括结构型微水灌溉技术的界面结构输水机理及水滴形成原理、自调节土壤湿度水分子渗灌材料结构自微动态原理及传水动力学、仿生凝露材料初步的科学分析及仿生结构试验、沙表结皮生物材料的储水原理和特点,结合沙漠水资源特点推测了沙漠水科学材料未来的研究领域和特征,提出了"智能灌溉"和"无水灌溉"的新材料技术将是未来发展的主导方向。     

十六烷基三甲基溴化铵改性蒙脱土的制备及其保水性能

针对荒漠化地区沙土水分涵养难的问题,用十六烷基三甲基溴化铵(hexadecyl trimethyl ammonium bromide,CTMAB)插层改性制备有机蒙脱土保水材料。研究了材料在模拟沙漠气候条件下的保水性能,并采用X射线衍射分析、傅里叶红外光谱分析、热重分析、扫描电子显微镜对材料进行分析和表征。结果表明,CTMAB插层进入蒙脱土层间,(001)面层间距由1.25104nm增大到2.09212nm,同时该材料保水性能良好,CTMAB亲水端进入蒙脱土层间,将松散的蒙脱土颗粒胶结起来,其憎水端相互连接形成憎水网络,从而在地表形成透气保水的固结层来有效降低水分蒸发。模拟沙漠气候条件下的植草试验表明,施用该材料后草籽发芽率从对照组的8%提高到48%。     

Preparation and water retention properties of montmorillonite modified by EL-10 emulsifying agent

Aiming at the problem of available water conservation in desertification ecological restoration, we prepared the water retention materials with montmorillonite(MMT) modified by Castor Oil Polyoxyethylene Ether(10) (EL-10) emulsifying vegetable waxes. The water retention property was studied in simulated desertification climate, and the materials were analyzed and characterized by UV-Vis, SEM, FTIR and XRD measurements. Moreover, a UV carbon arc lamp was used to test the resistance to aging. The experimental results show that the emulsion has good dispersity. Both the water retention property and the aging resistance performance of the modified clay were excellent. The lamellar structure and chemical composition of MMT had no obvious changes before and after modification. The surfaces of clay particles were coated uniformly with modified MMT, so the loose clay particles were cemented together by vegetable waxes. Meanwhile, the original big hydrophilic pores between the clay particles turned into capillary hydrophobic pores. So the clay particles formed a bonding layer which could inhibit water evaporation. Grass-planting experiment showed that reasonable mass ratio of vegetable waxes and EL-10 was 1:18. The materials not only had great water retention property but also maintained sound air permeability so that the germination rate of grass seed significantly increased from 8% to 52%.     

基于“做中学”理念的无机非金属材料工程专业综合实践教学改革策略——以中北大学为例

文章提出了构建“做中学”教学理念下的专业综合实践教学体系的改革策略,通过开设专业基础实验、设计性项目实验和开放性项目实验来构建多层次的实践教学载体;利用多元化的教学内容、开放式的教学管理来激发学生自主学习的能力;推行整合性实践教学模式来培养学生团队合作能力和实践创新能力;实行注重教学过程和产出教学成果的考核评价来调动学生的专业兴趣和学习主动性。