A new approach of preparing monolithic silica column was founded by adopting an improved sol-gel technology with tetramethoxysilane and polyethylene glycol as the matrix materials. The reason of resulting in crack and deformation of monolithic column was explained. By using N,N-dimethylformamide and a heat treatment procedure, the problems of crack and deformation in preparing the column were solved and the drying time was shortened greatly. In addition, the methods of fabricating mesopore and the effects of porogen solvent of different concentrations on monolithic silica column were investigated. The results show that the column prepared possessed bimodal pores structures with micrometer-size co-continuous through-pores and silica skeletons which have nanometer-size mesopores, straight appearance, high porosity, good chemical and mechanical stability. The characteristics would favour the separation with a rapid speed and high efficiency for both small molecules and macromolecules.
为探明荒漠植物沙柳（Salix psammophila）根围AM真菌时空异质性,2009年5月、8月和10月分别从内蒙古荒漠植物沙柳根围分0~10,11~20,21~30,31~40和41~50 cm 5个土层采集土壤样品,研究了AM真菌时空分布及与土壤因子的相关性.结果表明,沙柳根围AM真菌平均孢子密度为282个/100g,平均总定殖率0.642;从土壤中共分离AM真菌3属20种,其中球囊霉属（Glomus）15种、无梗囊霉属（Acaulospora）4种、盾巨孢囊霉属（Scutellospora）1种.AM真菌孢子密度、菌丝定殖率和丛枝定殖率随时间变化先升后降,最大值出现在8月;泡囊定殖率随时间变化先降后升,最大值出现在10月;随土壤深度增加,孢子密度和定殖率下降,最大孢子密度和最高定殖率均出现在10月份0~10 cm土层.孢子密度与土壤温度、pH极显著正相关,与土壤速效P极显著负相关;泡囊定殖率与土壤碱解N显著正相关;丛枝定殖率与土壤温度、湿度和pH极显著正相关,与土壤碱解N极显著负相关;菌丝定殖率与易提取球囊霉素极显著正相关.总球囊霉素和易提取球囊霉素与土壤碱解N和有机C极显著正相关.球囊霉素含量的动态变化能够综合反映土壤AM真菌分布和活动、有机C动态和养分循环进程,应作为荒漠土壤质量和功能评价的新指标进一步深入研究.
