Cavitation generation methods have been used in multifarious directions because of their diversity,and numerous studies and discussions have been conducted on cavitation generation methods.This study aims to explore t...Cavitation generation methods have been used in multifarious directions because of their diversity,and numerous studies and discussions have been conducted on cavitation generation methods.This study aims to explore the generating mechanism and evolution law of volume alternate cavitation(VAC).In the VAC,liquid water is placed in an airtight container with a variable volume.As the volume alternately changes,the liquid water inside the container continues to cavitate.Then,the mixture turbulence model and in-cylinder dynamic grid model are adopted to conduct computational fluid dynamics simulation of volume alternate cavitation.In the simulation,the cloud images at seven heights on the central axis are monitored,and the phenomenon and mechanism of height and eccentricity are analyzed in detail.By employing the cavitation flow visualization method,the generating mechanism and evolution law of cavitation are revealed.The synergistic effects of experiments and high-speed camera capturing confirm the correctness of the simulation results.In the experiment,the volume change stroke of the airtight container is set to 20 mm,the volume change frequency is 18 Hz,and the shooting frequency of the high-speed camera is set to 10000 FPS.The experimental results indicate that the position of the cavitation phenomenon has a reasonable law during the whole evolution cycle of the cavitation cloud.Also,the volume alternation cycle corresponds to the generation,development,and collapse stages of cavitation bubbles.展开更多
目的 vac A 基因编码的蛋白是幽门螺杆菌的一个重要毒力因子,通过空泡化作用损伤上皮细胞.vacA 基因与 Hp 感染者的临床发病有着密切的关系,vacA 的基因型决定毒素蛋白体外表达水平的高低.我们从幽门螺杆菌88022菌株中扩增出vacA 基因...目的 vac A 基因编码的蛋白是幽门螺杆菌的一个重要毒力因子,通过空泡化作用损伤上皮细胞.vacA 基因与 Hp 感染者的临床发病有着密切的关系,vacA 的基因型决定毒素蛋白体外表达水平的高低.我们从幽门螺杆菌88022菌株中扩增出vacA 基因毒性相关片段,进行序列测定和序列比较分析,为Hp 的临床检测奠定基础.方法以该菌株总 DNA 为模板,紧随 vacA 基因序列 s 区保守区域的引物(位于316bp～335bp 和1198bp～1218bp)扩增vacA 基因的一个903bp 片段,编码的氨基酸为34～334位,用13amHI 和 Pst Ⅰ双酶切后克隆入 pGEM-3Zf(-)质粒载体,以双脱氧法双向测定目的片段的序列,拼接出该片段的全序列,并与已知的 Hp vacA 基因序列作比较.结果所得序列与 Hp 国际标准株 CCUG17874(GeneBank gi619248)和 NCTCll638(GeneBank gi 495469)的 vacA 基因序列完全一致,氨基酸序列分析和所报道的结果一致.结论构建了 Hp vacA 基因毒性相关片段的重组克隆,为以后的进一步研究奠定了基础.展开更多
基金Supported by National Nature Science Foundation of China(Grant No.51575245)Jiangsu Provincial Key research and development program(Grant No.BE2015134)Zhenjiang Municipal Key Research and Development Project(Grant No.KZ2020001).
文摘Cavitation generation methods have been used in multifarious directions because of their diversity,and numerous studies and discussions have been conducted on cavitation generation methods.This study aims to explore the generating mechanism and evolution law of volume alternate cavitation(VAC).In the VAC,liquid water is placed in an airtight container with a variable volume.As the volume alternately changes,the liquid water inside the container continues to cavitate.Then,the mixture turbulence model and in-cylinder dynamic grid model are adopted to conduct computational fluid dynamics simulation of volume alternate cavitation.In the simulation,the cloud images at seven heights on the central axis are monitored,and the phenomenon and mechanism of height and eccentricity are analyzed in detail.By employing the cavitation flow visualization method,the generating mechanism and evolution law of cavitation are revealed.The synergistic effects of experiments and high-speed camera capturing confirm the correctness of the simulation results.In the experiment,the volume change stroke of the airtight container is set to 20 mm,the volume change frequency is 18 Hz,and the shooting frequency of the high-speed camera is set to 10000 FPS.The experimental results indicate that the position of the cavitation phenomenon has a reasonable law during the whole evolution cycle of the cavitation cloud.Also,the volume alternation cycle corresponds to the generation,development,and collapse stages of cavitation bubbles.
文摘目的 vac A 基因编码的蛋白是幽门螺杆菌的一个重要毒力因子,通过空泡化作用损伤上皮细胞.vacA 基因与 Hp 感染者的临床发病有着密切的关系,vacA 的基因型决定毒素蛋白体外表达水平的高低.我们从幽门螺杆菌88022菌株中扩增出vacA 基因毒性相关片段,进行序列测定和序列比较分析,为Hp 的临床检测奠定基础.方法以该菌株总 DNA 为模板,紧随 vacA 基因序列 s 区保守区域的引物(位于316bp～335bp 和1198bp～1218bp)扩增vacA 基因的一个903bp 片段,编码的氨基酸为34～334位,用13amHI 和 Pst Ⅰ双酶切后克隆入 pGEM-3Zf(-)质粒载体,以双脱氧法双向测定目的片段的序列,拼接出该片段的全序列,并与已知的 Hp vacA 基因序列作比较.结果所得序列与 Hp 国际标准株 CCUG17874(GeneBank gi619248)和 NCTCll638(GeneBank gi 495469)的 vacA 基因序列完全一致,氨基酸序列分析和所报道的结果一致.结论构建了 Hp vacA 基因毒性相关片段的重组克隆,为以后的进一步研究奠定了基础.
