CO_(2)管道输送作为碳捕集、利用和封存(carbon capture,utilization and storage,CCUS)技术中的连接碳源和碳汇的关键环节,未来将在实现碳中和过程中发挥重要作用。对于管道水击工况,其产生的压力震荡可能超过管内承压和低于泵的进站...CO_(2)管道输送作为碳捕集、利用和封存(carbon capture,utilization and storage,CCUS)技术中的连接碳源和碳汇的关键环节,未来将在实现碳中和过程中发挥重要作用。对于管道水击工况,其产生的压力震荡可能超过管内承压和低于泵的进站压力。目前,超临界CO_(2)管道水击及控制理论还不成熟。建立以质量、动量和能量守恒定律为基础的描述管道内一维气体流动的数学模型,采用特征线法进行求解,利用MATLAB编程计算,分别与Kiuchi提出的输气系统模型的模拟结果和商业软件OLGA模拟的结果进行对比分析。结果表明:与输气系统模型的模拟结果大体一致,与OLGA软件计算压力和流量的最大相对误差分别为0.02%和2.32%,满足工程计算精度的要求。对于管道压缩机启停、阀门紧急开关和流量急剧变化等在较短时间内引起管道参数变化的快瞬变过程,通过设置急剧变化值进行模拟,所建立的模型能够计算出各个节点的参数变化情况且精度较高,可为超临界CO_(2)管道输送工艺仿真软件国产化提供理论支持与技术支持。展开更多
目的采用成簇的规律性间隔短回文重复序列及其相关蛋白9(clustered regulatory interspaced short palindromic repeats/CRISPR-associated protein 9,CRISPR/Cas9)系统构建基因敲除细胞文库,以人结肠腺癌细胞Caco-2为研究对象构建稳定...目的采用成簇的规律性间隔短回文重复序列及其相关蛋白9(clustered regulatory interspaced short palindromic repeats/CRISPR-associated protein 9,CRISPR/Cas9)系统构建基因敲除细胞文库,以人结肠腺癌细胞Caco-2为研究对象构建稳定表达Cas9蛋白的细胞系。方法包装重组Cas9慢病毒并感染Caco-2细胞,经杀稻瘟菌素及2次有限稀释法筛选Caco-2/Cas9单克隆细胞,并进行PCR和Western blot鉴定。用同时表达GFP和带有GFP向导RNA(single guide RNA,sgRNA)的慢病毒感染Caco-2/Cas9单克隆细胞,经嘌呤霉素筛选后,采用流式细胞术检测结果计算Caco-2细胞株的敲除效率,CCK-8法检测其细胞增殖活性。结果共获得5株Caco-2/Cas9单克隆细胞系,分别命名为Caco-2/Cas9-2、Caco-2/Cas9-3、Caco-2/Cas9-4、Caco-2/Cas9-5和Caco-2/Cas9-6,均可扩增出392 bp的Cas9基因条带,Cas9蛋白在细胞中稳定表达,敲除效率分别为91.27%、20.30%、24.13%、11.33%、12.27%、8.89%;Caco-2/Cas9-4、Caco-2/Cas9-5、Caco-2/Cas9-63株单克隆细胞及未感染Caco-2细胞的增殖活性分别为2.07、1.75、1.46和1.40。Caco-2/Cas9-5、Caco-2/Cas9-6单克隆细胞与未感染Caco-2细胞比较,差异均无统计学意义(t分别为1.92和0.37,P均>0.05)。结论筛选出1株具有Cas9高酶切活性且细胞增殖活性较未感染Caco-2细胞无显著变化的Caco-2/Cas9单克隆细胞系,即Caco-2/Cas9-6单克隆细胞,为进一步构建高覆盖率敲除细胞文库奠定了基础,也为筛选病毒感染有关基因和其他特定功能基因提供了平台。展开更多
The suitability of 1-nitroso-2-naphthol(NN) as a complexing agent for on-line preconcentration of cobalt eluted on the C_(18) microcolumn by means of the FI-FAAS system was tested. Various parameters affecting the com...The suitability of 1-nitroso-2-naphthol(NN) as a complexing agent for on-line preconcentration of cobalt eluted on the C_(18) microcolumn by means of the FI-FAAS system was tested. Various parameters affecting the complex formation and its elution were optimized. A 2.3×10^(-3) mol/L reagent solution and the aqueous sample solution acidified with 0.1% (volume fraction) nitric acid were on-line mixed (6.4 mL/min) on a reaction coil set at (65±1)℃ and flowed through the microcolumn for 30 s. The pH of the mixed solution was adjusted to 3—4 with HNO_3(1 mol/L) or NaOH(1 mol/L). The adsorbed complexes in the microcolumn were eluted into the nebulizer of FAAS in 10 s with ethanol acidified with 1% HNO_3(3.0 mL/min). A good precision(1.6% for 100μg/L Co(Ⅱ), n=10), a high enrichment factor 17.2, with detection limit (3σ) 3.2μg/L, and sample throughput (90 h^(-1)) were obtained. The method was applied to the certified reference materials(CRMs), NBS-362 and NBS-364, for the determination of cobalt and the results were in good agreement with the certified values.展开更多
文摘CO_(2)管道输送作为碳捕集、利用和封存(carbon capture,utilization and storage,CCUS)技术中的连接碳源和碳汇的关键环节,未来将在实现碳中和过程中发挥重要作用。对于管道水击工况,其产生的压力震荡可能超过管内承压和低于泵的进站压力。目前,超临界CO_(2)管道水击及控制理论还不成熟。建立以质量、动量和能量守恒定律为基础的描述管道内一维气体流动的数学模型,采用特征线法进行求解,利用MATLAB编程计算,分别与Kiuchi提出的输气系统模型的模拟结果和商业软件OLGA模拟的结果进行对比分析。结果表明:与输气系统模型的模拟结果大体一致,与OLGA软件计算压力和流量的最大相对误差分别为0.02%和2.32%,满足工程计算精度的要求。对于管道压缩机启停、阀门紧急开关和流量急剧变化等在较短时间内引起管道参数变化的快瞬变过程,通过设置急剧变化值进行模拟,所建立的模型能够计算出各个节点的参数变化情况且精度较高,可为超临界CO_(2)管道输送工艺仿真软件国产化提供理论支持与技术支持。
基金Supported by Zhejiang Natural Science Foundation of China.
文摘The suitability of 1-nitroso-2-naphthol(NN) as a complexing agent for on-line preconcentration of cobalt eluted on the C_(18) microcolumn by means of the FI-FAAS system was tested. Various parameters affecting the complex formation and its elution were optimized. A 2.3×10^(-3) mol/L reagent solution and the aqueous sample solution acidified with 0.1% (volume fraction) nitric acid were on-line mixed (6.4 mL/min) on a reaction coil set at (65±1)℃ and flowed through the microcolumn for 30 s. The pH of the mixed solution was adjusted to 3—4 with HNO_3(1 mol/L) or NaOH(1 mol/L). The adsorbed complexes in the microcolumn were eluted into the nebulizer of FAAS in 10 s with ethanol acidified with 1% HNO_3(3.0 mL/min). A good precision(1.6% for 100μg/L Co(Ⅱ), n=10), a high enrichment factor 17.2, with detection limit (3σ) 3.2μg/L, and sample throughput (90 h^(-1)) were obtained. The method was applied to the certified reference materials(CRMs), NBS-362 and NBS-364, for the determination of cobalt and the results were in good agreement with the certified values.
