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烟草叶片生长的动态分析   总被引:2,自引:1,他引:1  
对烟草品种K326叶片的发生和叶面积扩展规律进行了动态研究.结果表明,K326烟草叶片的出叶速度前期慢、后期快,前期(4~8叶)5~6d、中期(9~18叶)2~3d、后期(19~34叶)1~2d出一片叶.叶片的长宽比在1. 45~2.63之间,长宽比在低位叶处较小,随叶位的上升而增大,在高位叶又有所下降,打顶后的高位叶长宽比值下降较小.各叶位叶片长、宽和叶面积均有相似的扩展规律,用Richards方程拟合有很高的拟合度.使用该方程,可以获得一些与烟叶生长、发育和烟叶生产相关的生长参数.平均而言,达到最终叶面积一半的时间约需16.4d,生长速率达最大值约在出叶后14.77d.达到最终叶面积99%的实际生长期约需36.8d.打顶后,叶片的实际生长期更长.各叶位的长、宽和叶面积随叶位的增加而增加,至25叶后,增加的幅度变小,这种变化趋势也可用Richards方程较好的描述.  相似文献
2.
Monitoring calcium concentration in neurons with cameleon   总被引:1,自引:0,他引:1  
The calcium ion, a second messenger in the brain, plays key roles in neuronal signaling pathways. Ca(2+) signals in neurons are often highly localized and difficult to measure accurately. The quantification of calcium concentration is thus critical for understanding neuronal signaling. In this study, a yellow cameleon (YC3.60) excited using a 458 nm laser was used to monitor the calcium signals in neurons, and the dynamic range (R(max)/R(min)) of YC3.60 was found to reach 250%. The spatial distribution of calcium and the physiological changes in hippocampal neurons and even in spines were determined by the fluorescence resonance energy transfer (FRET) method. It was proved that cameleon could be used for the quantitative measurement of calcium concentration in neurons. Fluorescence readout of the calcium concentration in neurons by FRET is nondestructive, quantifiable with high spatiotemporal resolution, and even applicable to dendritic spines.  相似文献
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The objective of this study was to investigate the effects of superfine grinding on the physicochemical and antioxidant properties of Lycium barbarum polysaccharides (LBP). Superfine grinding treatment could decrease the average molecular weight (changed from 834.0, 85.2 and 70.6 to 538.5, 71.2 and 2.1, respectively), the spherical particle’s heights (changed from 0.86, 0.59 and 0.51 nm to 0.74, 0.55 and 0.43 nm, respectively) and the spherical particle’s diameter (changed from 98.33, 70.67 and 86.33 nm to 88.67, 47.67 and 51.33 nm, respectively) of LBP. After being superfine grinding treated, the ΔH values of LBP changed from −154.6, −136.5 and −105.0 J/g to −220.8, −97.2 and −46.5 J/g, respectively. The IC50 of LBP from treated materials on DPPH radical (4.96, 1.98 and 2.97 mg/mL) and ABTS radical (2.25, 0.20 and 0.25 mg/mL) were extremely lower than those of LBP from untreated materials. The results suggested that superfine grinding treatment enhanced LBP’s antioxidant activities. Molecular weight and solution behavior were key factors in polymer’s antioxidant activities.  相似文献
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在传统植酸钙制备工艺的基础上对米糠植酸钙的精制工艺进行了优化,并对其米糠残渣的营养成份进行了分析。结果表明粗品植酸钙最佳酸浸条件为温度为60℃,pH为1.5,酸浸时间为8 h,酸浸料液比为1∶10,在此条件下,采用二次碱沉法,200 g米糠,可获得粗品植酸钙18.8 g,粗品植酸钙的得率为9.4%,其植酸质量分数为80.9%。利用活性炭对粗品植酸钙酸溶液进行脱色,其最适的脱色条件为温度40℃,时间60 min,活性炭的量为8%(W/V),两次脱色效果明显优于一次脱色。在此条件下,10 g粗品植酸钙制得精制植酸钙7.63 g,得率为76.3%,植酸回收率为77.4%。可见光区光谱扫描显示精制植酸钙酸溶液在380~800nm的吸光度比粗品植酸钙均下降了60%以上,所得精制植酸钙的酸溶液近乎无色,脱色效果较好。与未提取植酸的米糠相比,提取植酸后的米糠残渣中粗蛋白、脂肪、粗纤维、无氮浸出物等营养成份变化不大,而其总磷的43.6%以植酸的形式转入酸浸提液中,使得米糠残渣的营养成分更利于动物的吸收。  相似文献
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生物漂白是利用微生物分泌的木素降解酶酶系,在木聚糖酶的协同作用下,分解纸浆中的残余木素,并使之降解溶出的过程,其目的主要是提高纸浆的可漂性(以纸浆kappa值、粘度和白度的趸化作为衡量的指标),降低漂白化学药品用量,从而降低漂白废水污染负荷。主要从以下三个方面进行研究:(1)微生物(白腐菌)直接作用纸浆进行生物漂白;(2)半纤维素酶参与的纸浆生物漂白;木素降解的生物漂白。目前纸浆生物漂白新工艺无疑是制浆技术革新中最有发展前景、最诱人的课题之一。如果能用酶完全取代化学试剂进行生物漂白,可从源头上解决困扰造纸工业发展的漂白废水污染问题。我国在纸浆生物漂白方面的研究才刚刚起步,目前还处于实验室研究阶段,应用于工厂实践还需借鉴国外的先进经验。因此,关于这方面技术,值得我们继续去研究、开发。  相似文献
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