针对当前大米仓储管理缺乏系统性的问题,结合"物理-事理-人理(wuli-shili-renli,WSR)"方法论和层次分析法对大米仓储管理影响因素进行研究.通过构建大米仓储分析框架与评价模型,用权重计算的方法将大米仓储系统的权重数据指标精准量化.结果表明:大米仓储管理中最重要的影响因素是流通管理中的大米运送风险,权重值达0.324 6,占据大米仓储管理总权重的1/3.通过控制大米运送风险来降低大米仓储管理风险,仓储效率可得到提高.

A room temperature ionic liquid,1-allyl-3-methylimidazolium tetrafluoroborate(BF4) was prepared by a two-step synthesis.Then gel polymer electrolytes(GPE) prepared by incorporating the ionic liquid BF4 and poly(methyl methacrylate)(PMMA) were modified with aprotic solvents propylene carbonate(PC) and dimethyl carbonate(DMC) and SiO2 nano particles.The structure and properties of the GPE were studied by means of fourier transform infrared spectroscopy(FT-IR),A.C.impedance(AC),thermogravimetry(TG),and scanning electron microscope(SEM).The results showed that the introduction of aprotic solvents PC-DMC and nano-SiO2 particles increased the ionic conductivity of the GPE,which showed a highly ionic conductivity of up to 5.25×10-3 S/cm at room temperature.In addition,the conductive behavior of the GPE follows an Arrhenius equation.The gel polymer electrolytes shows high thermal stability and tends to decompose at temperature higher than 300 ℃.

In order to isolate a tacrolimus producing strain,soil samples were initially treated with 75 μg/mL K2Cr2O7 and 2 μg/mL benzylpenicillin.Seventy-one actinomycetes were isolated by anti-fungal activity against Candida albicans then the metabolites origin from those isolations were further analysis by HPLC.Among these,only one tacrolimus producing strain was determined.It was identified by culture characteristics,morphological characteristics,physiological,biochemical properties and 16S rDNA sequence and phylogenetic analysis.The screened strain was gram-positive,the growth temperature ranged from 15 ℃ to 38 ℃(the optimum was 28 ℃);the growth pH ranged from 6.5 to 8.5(the optimum at 7.0).The strain can grown on glucose,sucrose,maltose,xylose,fructose,lactose and rhamnose.Based on the results of the general taxonomical characteristics and the 16S rDNA sequence,the isolated has proven to be Streptomyces and named Streptomyces sp.NJYH2618.

The chemical structure and properties of ascomycin are introduced,and the current application situation is reviewed.The progress in production of ascomycin via fermentation is presented with a discussion on existing problems.Technology of metabolic engineering used in fermentation is introduced especially.Furthermore,prospect for future research is proposed.