点云配准是实物和场景数字孪生模型构建的关键技术。为了适应航空工业高效、精确的虚实结合工业模式,提出了基于快速点特征直方图FPFH(Fast Point Feature Histogram)特征识别配准算法的数字孪生模型构建方法。该方法在保障精确性的前提...点云配准是实物和场景数字孪生模型构建的关键技术。为了适应航空工业高效、精确的虚实结合工业模式,提出了基于快速点特征直方图FPFH(Fast Point Feature Histogram)特征识别配准算法的数字孪生模型构建方法。该方法在保障精确性的前提下,通过数字化检测、信息采集、数据处理与融合,构建物理与虚拟高效互通的数字孪生模型。最后,以燃气涡轮式航空发动机中尾喷管风扇类零件为实例,验证该方法应用于该类发动机零件用于构建数字孪生模型的可行性,并最终将该方法作用于整个涡扇发动机。展开更多
目的:建立参葛补肾胶囊中淫羊藿苷、朝藿定A、朝藿定B、朝藿定C含量的HPLC测定方法。方法:采用高效液相色谱法,色谱柱为Waters ACQUITY UPLC HSS T3 C 18(2.1×100 mm,1.8μm),流动相为乙腈-0.05%磷酸水溶液体系,梯度洗脱,流速为0.3...目的:建立参葛补肾胶囊中淫羊藿苷、朝藿定A、朝藿定B、朝藿定C含量的HPLC测定方法。方法:采用高效液相色谱法,色谱柱为Waters ACQUITY UPLC HSS T3 C 18(2.1×100 mm,1.8μm),流动相为乙腈-0.05%磷酸水溶液体系,梯度洗脱,流速为0.3 mL·min^(-1),检测波长为320 nm,柱温为30℃,进样量为2μL。以淫羊藿苷为内参物,采用斜率校正法计算其他3个成分的相对校正因子,比较外标法和一测多评法(QAMS)测定结果,验证一测多评法的可行性及准确性。结果:淫羊藿苷、朝藿定A、朝藿定B、朝藿定C分别在7.130~713.38μg·mL^(-1)、1.284~128.4μg·mL^(-1)、5.108~510.8μg·mL^(-1)、4.360~435.67μg·mL^(-1)质量浓度范围内存在良好的线性关系,线性系数R 2均大于0.99,平均加样回收率分别为104.5%、99.69%、100%、98.59%,RSD分别为1.4%、2.7%、1.2%、2.8%。朝藿定A、朝藿定B、朝藿定C的相对校正因子为1.31、1.19、1.17。一测多评法和外标法测定结果比较,其差异无统计学意义(P>0.05)。结论:该方法准确、简便、重复性好,可作为参葛补肾胶囊中淫羊藿总黄酮醇苷的质量控制研究。展开更多
Specific primers for the MC1R gene of alpacas(GenBank EU1358800) were designed to amplify the cDNA sequence using RT-PCR to seek variation in the sequence and explore the relationship between the expression level of M...Specific primers for the MC1R gene of alpacas(GenBank EU1358800) were designed to amplify the cDNA sequence using RT-PCR to seek variation in the sequence and explore the relationship between the expression level of MC1R gene and alpaca coat color.The MC1R gene from white alpaca was cloned successfully and sequence analysis verified that the MC1R gene,encoding 317 amino acids,was 1081 bp in length.Compared with the existing sequence in GenBank,sequence identity was 99.9%and 7 mutations were found.Primers,designed from the sequence obtained,were used to assess the relative expression of MC1R in alpacas of different coat color using QRT-PCR and SPSS 13.0 software.Relative expression of MC1R in the skin of brown alpacas was 4.32 times higher than that in white alpacas after normalization with GAPDH(P【0.01),indicating that MC1R expression may be related to coat color of alpacas.展开更多
文摘点云配准是实物和场景数字孪生模型构建的关键技术。为了适应航空工业高效、精确的虚实结合工业模式,提出了基于快速点特征直方图FPFH(Fast Point Feature Histogram)特征识别配准算法的数字孪生模型构建方法。该方法在保障精确性的前提下,通过数字化检测、信息采集、数据处理与融合,构建物理与虚拟高效互通的数字孪生模型。最后,以燃气涡轮式航空发动机中尾喷管风扇类零件为实例,验证该方法应用于该类发动机零件用于构建数字孪生模型的可行性,并最终将该方法作用于整个涡扇发动机。
文摘碳纤维混杂增强复合材料由于具有重量轻、可设计性强等诸多优点,广泛用于汽车、海洋、航空航天等行业.根据固化剂与环氧树脂的配比化学原理,计算出石墨烯-碳纤维混杂增强树脂基(GO-CF/EP)复合材料的最佳配比为1∶5,并采用真空浸渗热压成型工艺(VIHPS)制备1∶2~1∶7共六个配比的试样,结合形状记忆性能测试及微观形貌的观察,得到固化剂与环氧树脂实际最佳配比.实验结果表明,GO-CF/EP复合材料性能主要取决于体系中交联度的大小,交联度越大,复合材料的形状记忆性能越好,微观组织形貌也较理想.当基体配比为1∶5时,GO-CF/EP复合材料体系中交联度最大,微观形貌呈现均匀致密的状态,形状固定率最大,为95.90%;形状回复率最大,为95.40%;形状回复时间最短,为80.30 s;形状回复力最大,为9.48 N.当基体配比为1∶2或1∶7时,固化剂过量或不足,交联度较小,微观组织形貌中有大量的基体聚集区,其形状记忆性能下降,形状固定率及回复率也相应减小,分别为82.99%,81.66%,81.91%,78.75%;形状回复力分别只有5.20 N和5.50 N.
基金supported by the National Natural Science Foundation of China(No.30501070)Shanxi Natural Science Foundation(No.20041099)President Foundation of Agricultural University of Hebei (BS2007023)
文摘Specific primers for the MC1R gene of alpacas(GenBank EU1358800) were designed to amplify the cDNA sequence using RT-PCR to seek variation in the sequence and explore the relationship between the expression level of MC1R gene and alpaca coat color.The MC1R gene from white alpaca was cloned successfully and sequence analysis verified that the MC1R gene,encoding 317 amino acids,was 1081 bp in length.Compared with the existing sequence in GenBank,sequence identity was 99.9%and 7 mutations were found.Primers,designed from the sequence obtained,were used to assess the relative expression of MC1R in alpacas of different coat color using QRT-PCR and SPSS 13.0 software.Relative expression of MC1R in the skin of brown alpacas was 4.32 times higher than that in white alpacas after normalization with GAPDH(P【0.01),indicating that MC1R expression may be related to coat color of alpacas.