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31.
Duan Zhong-Hua Quan Xiao-Long Qiao You-Ming Li Xiao-Qing Pei Hai-Kun He Gui-Fang 《Russian Journal of Ecology》2019,50(1):20-26
Russian Journal of Ecology - The present study was conducted to investigate the n-alkane composition of typical alpine meadows. Plant and soil samples were collected and analyzed to characterize... 相似文献
32.
Channa argus, a type of snakehead fish native to China, is a popular food fish in certain Asian countries but is a known destructive invasive species in the US. In this study, the two collagens, i.e. acid-soluble collagen (ASC) and pepsin-solubilized collagen (PSC), were obtained from C. argus skin. The yield of ASC was 28.0% and that of PSC was 16.8% on the dry bases. The collagens were identified as the collagen of type I by SDS–PAGE patterns. The Tds were approximately 27.0?°C. Similar ultraviolet spectra of both collagens were observed. Fourier Transform infrared spectra indicated PSC structure had a little change due to the loss of terminal domains by pepsin digestion. The results of XRD proved that the two collagens retained their helical structures. The results suggest that the collagens isolated from C. argus can potentially be alternative sources of vertebrate collagens for use in the food and other industries. 相似文献
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采用在活化硅酸制备过程中加入适量Ti Cl4的方法,试制了一种新型无机高分子助凝剂—聚硅酸钛。研究了不同[Si]/[Ti]条件下制备的聚硅酸钛在固定p H值的水中分散物的粒径和Zeta电位随着活化时间的变化趋势,并与活化硅酸作比较。结果表明,在Si/Ti=20,活化48 h的条件下能制备出较为稳定的聚硅酸钛。与活化硅酸相比,聚硅酸钛在水中的分散物具有较大的粒径和更高的Zeta电位。通过对比制备的活化硅酸和聚硅酸钛的红外图谱发现,聚硅酸钛中有TiO-Si键,证明钛离子参与了聚合反应,新生成的化学键提高了它的聚合度和稳定性。采用硫酸铝为混凝剂,聚硅酸钛为助凝剂进行混凝除浊实验。测定了絮凝体的Zeta电位和混凝沉淀后的上清液浊度,研究了硫酸铝投加量和混凝p H对聚硅酸钛助凝效果的影响。结果表明,投加适量的聚硅酸钛助凝剂,明显提高了混凝除浊效果且拓宽了有效混凝p H值的范围。 相似文献
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36.
Qing Zhao Kebin He Kenneth A. Rahn Yongliang Ma Fumo Yang Fengkui Duan 《Atmospheric environment (Oxford, England : 1994)》2010,44(21-22):2615-2624
Depletion of Si in transported dust has been recognized for many years. It can be used to distinguish between transported and local dust in cities, although it rarely has been. Here we use the variations of the Si/Al ratio in 15 months of continuous PM2.5 samples at Beijing (northern China) and Chongqing (southwestern China) to reveal the seasonal patterns of their dust sources. For both cities, peaks of concentration for Si and Al in PM2.5 corresponded with minima of Si/Al, and could often be linked to pulsed air flow from deserts to the northwest. With significant depletion (up to 80%) and homogeneous distribution at urban and rural sites, Si/Al showed a clear seasonal evolution, which decreased from spring to summer, increased from fall to winter, and collapsed during Chinese Spring Festival, indicating the dominance of transported dust, local fugitive dust and firework influence, respectively. The low ratios implied that desert dust is a common source during spring at Chongqing, whereas its presence during cold season at Beijing was also more frequent than expected. Failing to recognize the depletion of Si may lead to an overestimate of desert dust by 15%–65% when using the average abundance of Al in crust (6%–8%), as in previous studies. The difference in Si/Al ratio between local and transported dust implies that >60% of the dust at Beijing came from outside the city during the springs of 2004–2006. This result can help resolve the contradictory findings on this topic that have been presented earlier. 相似文献
37.
新型SBBR处理畜禽废水脱氮实验研究 总被引:1,自引:0,他引:1
以畜禽废水为处理对象,将序批式运行模式应用到好氧三相内循环生物流化床中,考察在不同模式下的处理效果及氮的转化情况。实验结果表明,在室温条件下,进水COD浓度为2 000 mg/L左右,总氮为140 mg/L左右时,保持溶解氧在2~2.5 mg/L,交替好氧/缺氧运行方式处理效果优于单一的好氧/缺氧方式;模式为3 h(曝气)-1.5 h(停曝)-1.5 h(曝气)-1 h(停曝)时系统对总氮和氨氮处理效果最好,总氮去除率达到90%,系统主要脱氮方式为同步硝化反硝化和短程硝化反硝化。 相似文献
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用活性炭、酚醛树脂和乌洛托品制备了活性炭电极。利用扫描电子显微镜(SEM)、傅立叶变换红外光谱仪(FTIR)分析了电极的表面性质,发现电极表面的黏结剂可完全碳化,且活性炭上带有大量含氧官能团;利用电化学工作站采用循环伏安法对电极进行了测试,表明电吸附是一稳定而又可逆的过程,电极电流的最大值由碳化前的0.019 8A升至碳化后的0.042 7A,双电层电容提高到碳化前的2.16倍;对NaCl的电吸附实验表明碳化后电极的电吸附率是碳化前的1.59倍,活性炭的吸附容量也由1.14mg/g提高到3.29mg/g,且活性炭电极具有良好的重复利用性。 相似文献
40.
膨润土接枝丙烯酸高吸水性树脂的抑尘性能研究 总被引:2,自引:0,他引:2
在微波辐射下制备了膨润土接枝丙烯酸高吸水性树脂(SAP)(一种加入聚乙烯醇(PVA),另一种不加入PVA)。结果表明:(1)红外光谱图表明,PVA与聚合网络形成了半互穿网络结构;X射线衍射图表明,膨润土与PVA、丙烯酸形成了具有无定形结构的复合产物。(2)不论是沙土堆还是尘土堆,喷洒膨润土接枝丙烯酸SAP溶液的抑尘效果明显比喷洒自来水好;喷洒膨润土接枝丙烯酸SAP溶液的尘土堆的抑尘效果好于沙土堆。(3)在温度为15℃时,考虑到节约成本的问题,首选不加入PVA的膨润土接枝丙烯酸SAP做抑尘剂;在温度为45℃时,加入PVA的膨润土接枝丙烯酸SAP适合做抑尘剂。(4)膨润土接枝丙烯酸SAP浓度越高,其耐蒸发性越高。 相似文献