排序方式: 共有18条查询结果,搜索用时 15 毫秒
1.
2.
减压贮藏是果蔬贮藏中常用的保存方法.为评估减压贮藏保鲜技术对水果和蔬菜的保鲜效果,选取菠菜、西芹、彩椒3种蔬菜和草莓、蜜桃、青提、牛油果、樱桃5种水果,评估其减压贮藏条件(压力设置:80 kPa)和常压贮藏条件下的失重率和表面亮度值变化,选取菠菜对其叶绿素含量进行评估,并通过感官评定评价贮藏过程中水果和蔬菜的感官品质.结果显示,冷藏过程中叶类蔬菜相比茎类和果实类蔬菜更容易脱水失重,减压贮藏条件下3种蔬菜和5种水果的水分流失均较低,其中对青提水分流失的抑制效果最显著,减压贮藏7天比普通冰箱贮藏低8.1倍;且对水果和蔬菜的表面光泽、蔬菜的叶绿素均有较好的保持效果,感官评定结果也显示减压贮藏可提升贮藏过程中水果和蔬菜的感官品质.因此得出,减压贮藏保鲜技术对蔬菜和水果可起到较好的保鲜效果. 相似文献
3.
Functionalized ionic liquids containing ethyoxyl groups were synthesized and immobilized on magnetic silica nanoparticles(MSNP) prepared by two steps,i.e.,Fe3O4 synthesis and silica shell growth on the surface.This magnetic nanoparticle supported ionic liquid(MNP-IL) were applied in the immobilization of penicillin G acylase(PGA).The MSNPs and MNP-ILs were characterized by the means of Fourier transform infrared spectroscopy(FTIR),scanning electron microscopy(SEM),transmission electron microscopy(TEM),and vibrating sample magnetometer(VSM).The results showed that the average size of magnetic Fe3O4 nanoparticles and MSNPs were ~10 and ~90 nm,respectively.The saturation magnetizations of magnetic Fe3O4 nanoparticles and MNP-ILs were 63.7 and 26.9 A?m2?kg?1,respectively.The MNP-IL was successfully applied in the immobilization of PGA.The maximum amount of loaded enzyme was about 209 mg?g?1(based on carrier),and the highest enzyme activity of immobilized PGA(based on ImPGA) was 261 U?g?1.Both the amount of loaded enzyme and the activity of ImPGA are at the same level of or higher than that in previous reports.After 10 consecutive operations,ImPGA still main-tained 62% of its initial activity,indicating the good recovery property of ImPGA activity.The ionic liquid modified magnetic particles integrate the magnetic properties of Fe3O4 and the structure-tunable properties of ionic liquids,and have extensive potential uses in protein immobilization and magnetic bioseparation.This work may open up a novel strategy to immobilize proteins by ionic liquids. 相似文献
4.
根据实际工作中的实践经验,论述了变频调速器在实际应用中容易被忽略的接地、温度、电网电压等几个方面的问题,提出了解决这些问题的措施和方法。 相似文献
5.
与普通建筑相比,高层房屋建筑具有一定的结构复杂性以及较高技术要求等特点,因而对建筑施工技术的管理也提出更为严格的要求.为进一步提高高层建筑的水平以及保证建筑施工的质量,相关的工作人员应重视起现阶段高层建筑施工技术管理要点.所以下文将结合笔者参与过的实际工程项目来探讨高层房屋建筑施工技术管理中存在的问题与不足,通过采取提... 相似文献
6.
7.
8.
9.
杉根精油分离及其化学成分测定 总被引:2,自引:0,他引:2
用干馏工艺扩试提取杉根精油,干馏釜3m3,干馏温度105~420℃,时间6.0h,产品得率为6.08%,是水蒸气蒸馏提取方法的3倍。产品相对密度(25℃)为0.9912~1.021,折射率nD20为1.4799,旋光度+0.5°。应用GC法对100~250℃的精油化学成分进行了分析,分出41个色谱峰,共鉴定出39个化合物,占该精油总质量的99.16%,其中主要成分为α-蒎烯3.8010%(质量分数,下同),d-柠檬烯2.8893%,β-松油烯7.1880%,长叶烯10.4162%,β-石竹烯4.2064%,α-木罗烯3.017%,β-松油醇2.876%,β-榄香烯4.5719%,柏木醇31.5087%,愈创木醇6.1426%,实验结果表明,精油化学成分及含量因树龄、树的部位、提取工艺不同,差异很大。 相似文献
10.
目的分析挤压成形中车用下轴套零件成形表面出现的折叠缺陷,优化挤压上凹模的底部出口斜度、下凹模的入口斜度和挤压深度等主要成形工艺参数。方法采用DEFORM-3D软件,对汽车下轴套零件的冷挤压成形工艺进行了系统的有限元数值模拟试验。结果挤压成形模具结构设计不合理,导致在成形过程中模具分型面处金属出现汇流并形成折叠。结论通过优化挤压模具结构,使金属成形良好,无折叠缺陷出现,最终获得了较为合理的冷挤压模具结构。 相似文献