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111.
为了给基于频域反射法测量土壤质量含水率提供一种方法,设计了一种由圆管和探针组成的管针式土壤质量含水率测量探头。以杨凌地区的塿土为对象,分析了所设计探头间接测量土壤容重的误差;在信号源频率为50、100、150、300、500 MHz下,研究了土壤质量含水率(2.58%~21.43%)、土壤容重(0.80~1.30 g/cm3)和温度(10~50℃)对探针上的电压与信号源输出电压的比值(信号电压比)的影响;建立了信号电压比与土壤温度、容重和质量含水率之间的三元二次方程,分析了模型预测土壤含水率的可行性。结果表明:管针式探头间接测量土壤容重的绝对误差为-0.129~0.016 g/cm3;含水率、容重和温度均影响信号电压比,50、100、150 MHz下含水率对信号电压比影响较显著。在0.01的显著水平上,150 MHz下所建模型较优,其决定系数R2为0.849 6;对该模型的检验结果说明,计算的信号电压比与实际电压比的绝对误差为-0.166~0.159。基于该模型计算的土壤含水率与实际含水率的绝对误差为-3.440%~4.039%。 相似文献
112.
将用于厌氧消化反应器的载体经好氧挂膜预处理,采用有机负荷递增法启动厌氧附着膜膨胀床(AAFEB)反应器,好氧预处理后的反应器比对照提前15天完成启动,并且具有较好的耐冲击负荷能力和耐水力负荷能力。这与污泥结构良好,持留能力强,污泥流失量小呈正相关。在反应器的稳态运行和再启动运行期间,反应器的主要运行参数与对照反应器无明显差异。 相似文献
113.
随着沼气建设的快速发展,病态池的数量也随之增多。本文就如何分辨沼气池和输气线路病态、确定病态沼气池的病态类型、查找病态池漏水漏气部位及维修病态池提出了具体的方法。 相似文献
114.
针对逻辑建模在数据仓库构建过程中的重要性,介绍了数据仓库创建的基本步骤,并利用实例深入而详细地研究了逻辑模型的设计,分析了几种逻辑模型的特点及其使用场合。 相似文献
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从石阡县沼气池型的演变探讨该县区域群众满意的推广池型,对加快沼气建设步伐,减少森林砍伐,解决群众生活用能,推动“三沼”利用有极大作用。达到保护森林植被,改变生态环境,提高生活质量,实现生态效益和经济效益双赢。 相似文献
118.
Natalia V. Krylova Anna O. Kravchenko Olga V. Iunikhina Anastasia B. Pott Galina N. Likhatskaya Aleksandra V. Volodko Tatyana S. Zaporozhets Mikhail Y. Shchelkanov Irina M. Yermak 《Marine drugs》2022,20(1)
The structural diversity and unique physicochemical properties of sulphated polysaccharides of red algae carrageenans (CRGs), to a great extent, determine the wide range of their antiviral properties. This work aimed to compare the antiviral activities of different structural types of CRGs: against herpes simplex virus type 1 (HSV-1) and enterovirus (ECHO-1). We found that CRGs significantly increased the resistance of Vero cells to virus infection (preventive effect), directly affected virus particles (virucidal effect), inhibited the attachment and penetration of virus to cells, and were more effective against HSV-1. CRG1 showed the highest virucidal effect on HSV-1 particles with a selective index (SI) of 100. CRG2 exhibited the highest antiviral activity by inhibiting HSV-1 and ECHO-1 plaque formation, with a SI of 110 and 59, respectively, when it was added before virus infection. CRG2 also significantly reduced the attachment of HSV-1 and ECHO-1 to cells compared to other CRGs. It was shown by molecular docking that tetrasaccharides—CRGs are able to bind with the HSV-1 surface glycoprotein, gD, to prevent virus–cell interactions. The revealed differences in the effect of CRGs on different stages of the lifecycle of the viruses are apparently related to the structural features of the investigated compounds. 相似文献
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120.
Wen-Zhuo Zhu Shu-Heng Wang Hui-Min Gao Ya-Ming Ge Jun Dai Xiao-Ling Zhang Qiao Yang 《Marine drugs》2022,20(1)
Strain NJES-13T is the type strain and currently the only species of the newly established actinobacteria genera Aptenodytes in the family Dermatophilaceae isolated from the gut microbiota of the Antarctic emperor penguin. This strain demonstrated excellent bioflocculation activity with bacteria-derived exopolysaccharides (EPSs). Moreover, it produced bioactive angucycline/angucyclinone derivatives (ADs) and contained one type III polyketide synthase (T3PKS), thus demonstrating great potential to produce novel bioactive compounds. However, the low productivity of the potential new AD metabolite was the main obstacle for its chemical structure elucidation. In this study, to increase the concentration of targeted metabolites, the influence of cellular morphology on AD metabolism in strain NJES-13T was determined using glass bead-enhanced fermentation. Based on the cellular ultra-structural observation driven by bacterial EPSs, and quantitative analysis of the targeted metabolites, the successful increasing of the productivity of three AD metabolites was achieved. Afterward, a new frigocyclinone analogue was isolated and then identified as 2-hydroxy-frigocyclinone, as well as two other known ADs named 2-hydroxy-tetrangomycin (2-HT) and gephyromycin (GPM). Three AD metabolites were found to demonstrate different bioactivities. Both C-2 hydroxyl substitutes, 2-hydroxy-tetrangomycin and 2-hydroxy-frigocyclinone, exhibited variable inhibitory activities against Staphylococcus aureus, Bacillus subtilis and Candida albicans. Moreover, the newly identified 2-hydroxy-frigocyclinone also showed significant cytotoxicity against three tested human-derived cancerous cell lines (HL-60, Bel-7402 and A549), with all obtained IC50 values less than 10 µM. Based on the genetic analysis after genomic mining, the plausible biogenetic pathway of the three bioactive ADs in strain NJES-13T was also proposed. 相似文献