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高原空气细菌不同时间的观察未见报道，本文对９时、１３时和１８时空气细菌进行检测，结果各种细菌在三种时间的阳性检出率不尽相同，但经Ｘ＾２检验无显著性差异。各细菌在不同时间含量悄尽相同，普遍９时比１３时和１８时高，但经ｔ检验只有９时肠球菌与１３时和１８时比较有非常显著性和显著性差异，９时枯草杆菌与１３时有显著性差异，余无差异。空气细菌总含量９时与１３时和１８时比较都有非常显著性差异。结果表明，高原日照 相似文献
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目的:测定壬苯醇醚凝胶中壬苯醇醚含量.方法:以C18化学键合硅胶为固定相,以甲醇-水(90:10)为流动相,检测波长为280nm,用外标法计算含量.结果:壬苯醇醚浓度在0.2～0.6mg/ml范围内与峰面积线性关系良好,r=0.9908(n=5),平均回收率为99.56%,RSD=1.66%.结论:高效液相色谱法[1]可作为壬苯醇醚凝胶中壬苯醇醚含量的测定方法. 相似文献
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目的：测定壬苯醇醚凝胶中壬苯醇醚含量。方法：以C18化学键合硅胶为固定相,以甲醇-水（90：10）为流动相,检测波长为280nm,用外标法计算含量。结果：壬苯醇醚浓度在0．2～0．6mg／ml范围内与峰面积线性关系良好,r=-0．9908（n=5）,平均回收率为99．56％,RSD=1．66％。结论：高效液相色谱法可作为壬苯醇醚凝胶中壬苯醇醚含量的测定方法。 相似文献
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在电子烟烟碱液未经预处理以及经历在空气中多次蒸馏预处理两种条件下,采用热裂解气相色谱质谱(Py-GCMS)检测了电子烟烟碱液组分变化情况。未经预处理进行Py-GCMS时,由于烟碱液气化时与空气隔绝,气体组分的物质类型稳定,包含丙二醇、丙三醇和尼古丁,尼古丁含量低于10%;经历高温下空气中反复蒸馏预处理的烟碱液,气化后组分的物质类型和比例都与预处理的温度有关,蒸馏温度160℃时,尼古丁含量达到了21.07%。 相似文献
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呼出气体酒精含量探测器是用于检测人体呼出气体中的酒精含量的仪器。对其检测可使用液态有机气体配气装置、酒精呼气模拟器、瓶装空气中酒精有证标准气体三种方法。其中酒精呼气模拟器产生的气体为湿气,接近人体呼出气体模式,测量结果更为可靠。 相似文献
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目的:建立双氯芬酸钠滴眼液中苯扎氯铵的含量测定方法。方法:高效液相色谱法,HYPERSIL BDS(250mm×4.6mm,5μm)色谱柱,0.02mol/L庚烷磺酸钠溶液(含0.1%三乙胺,用磷酸调至pH3.45±0.1)——乙腈(35:65)为流动相,检测波长为210nm,柱温40℃。结果:苯扎氯铵在19.52～214.72ug/ml浓度范围内进样量与峰面积线性关系良好,平均回收率为102.60%,RSD值为0.52%。结论:本方法简便、准确,可有效测定双氯芬酸钠滴眼液中苯扎氯铵的含量。 相似文献
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利用同步辐射光和反射飞行时间质谱,研究了丙烯酸甲酯9.0~15.5 eV能量范围的真空紫外光电离和光解离.实验测量丙烯酸甲酯的光电离质谱和解离碎片离子m/e=86(C4H6O+2), 85(C4H5O+2), 59(C2H3O+2), 58(C3H6O+), 55(C3H3O+), 42(C3H+6), 31(CH3O+), 27(C2H+3), 和15(CH+3)的光电离效率曲线.并利用量子化学从头算(G3),计算碎片离子的能级,推测它们的解离通道.计算的电离能和出现势与实验结果符合很好.结果表明,丙烯酸甲酯的光电离解离通道以单键断裂反应为主. 相似文献
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利用简单的手性有机配体L-酒石酸成功地合成出了一系列类似DNA螺旋构型的左、右旋的一维链状聚合物：{A[Mo2VIO4LnIII(H2O)6(C4H2O6)2]·4H2O}n (Ln = Sm, Eu, Gd, Ho, Yb, Y; C4H2O6 = L- 或 D-酒石酸； A = NH4 或 H3O)。通过水热法，巧妙地把传统的钼氧单核{MoO4}、双核{Mo2O7}以及{Mo8O26}等结构单元，通过有机配体配位的过渡金属单元交错地连接成零、一、二、三维的一系列结构新颖的化合物，这类化合物大多数具有可以容纳客体小分子的隧道或空穴，如 [Cu(4,4’-bpy)]2MoO4·2H2O，[Cu(4,4’-bpy)]2Mo2O7，[Cu(4,4’-bpy)(Hnic)(H2O)]2Mo8O26等。首次利用水热法合成出了含稀土的杂多酸类化合物，[Gd(H2O)3]3[GdMo12O42]·3H2O。该化合物是由Silverton-型的 [GdMo12O42]9- 阴离子和配位的Gd3+ 阳离子组成的。在[GdMo12O42]9- 离子中首次把顺磁性的钆(III)离子引入到该构型的中心，并且通过九配位的钆(III)离子把它们连接成具有介孔结构的三维网状化合物。该化合物的获得为今后合成类似化合物提供了一个很好的范例。在水热法合成出的化合物，[Cu2(C8H6N2)2(C7H6N2)]2[Mo8O26] 中，首次捕捉到喹喔啉的氧化产物苯并咪唑，证明了在水热条件下含氮的芳香杂环类的有机配体可以被二价铜氧化，其氧化产物进而作为配体直接与铜原子配位，最终形成新颖的上述化合物。 相似文献
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用溶胶凝胶法在玻璃基板上以LiNb（OR）6先驱体溶液（用甲酸作稳定剂,乙二酸作对照实验）制备了铌酸锂薄膜,并对薄膜进行了IR、XRD和SEM表征,结果表明,生成的铌酸锂为多晶,与乙二酸相比,用甲酸作稳定剂制备的铌酸锂薄膜形貌更好。 相似文献
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基于IPv6的网络入侵检测技术研究 总被引：1，自引：0，他引：1
IPv6技术是下一代互联网的核心技术。通过分析现有网络安全系统的基本原理,针对IPv6网络的特点,提出在IPv6环境下采用基于协议分析和模式匹配技术相结合的入侵检测系统架构。采用该系统架构能够更快、更有效地处理信息数据帧和连接,同时能够判断一个通信的实际内容及具体含义,具有抗躲避性强、系统资源占用小、检测速度高、误报率低的特点。 相似文献
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Dalya Sh. Al-owaidi Moaed E. Algazally Alaa Sadeq Alawaad 《Indian journal of clinical biochemistry : IJCB》2021,36(3):304
This case–control study is aimed to evaluate serum concentration of Cyclin-Dependent Kinase 6 (CDK6) and the genetic association between rs2237572 CDK6 gene and breast cancer (BC) in Iraq. To attain this goal, 80 patients with BC as cases and 80 healthy individuals as controls were included. Further, BC patients were sorted according to the molecular classification into four subtypes of Luminal A, Luminal B, Her2/neu enriched and TPN. Serum concentration of CDK6 enzyme, allelic and genotypic frequencies of rs2237572 CDK6, and the occurrence of BC phenotype and its subtypes in the studied population were investigated. ELISA technique was used to perform the biochemical testing, while the molecular analysis was achieved by real-time PCR, high resolution melting analysis, conventional PCR, as well as sequencing analysis. The results revealed no significant difference in serum concentration of CDK6 enzyme between patients and healthy controls (p > 0.05). Also, no significant differences were shown between BC patients subtypes (p > 0.05). The rs2237572 CDK6 genotypes were associated with the BC and affirmed that allele C was inherited as a recessive risk factor. Moreover, a highly significant difference between patients’ subtypes in the genotypic frequency of rs2237572 (p < 0.01) was noted. Furthermore, the association of rs2237572 genotypes and CDK6 serum concentration in BC patients showed a considered significant difference between C/C and T/T, C/C and T/C and the CDK6 level (p < 0.05). Nevertheless, T/T and T/C did not show any significant difference with the CDK6 level. Hence, it was concluded that the rs2237572 of CDK6 gene is significantly correlated with BC. 相似文献
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通过采集广西区梧州某工业园区的PM10,采用石墨炉原子吸收法测定镉含量,根据JJF1059-1999《测量不确定度评定与表示》建立对影响测量结果的不确定度评定模型和方法,并进行了量化的评定,结果表明影响镉含量测定不确定度的主要因素为测量过程、试样制备和采样体积。在该样品镉含量测定中,环境空气PM10中镉含量为0.00926±0.00031μg/m3,k=2。 相似文献
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以热表面电离质谱计为分析手段，采用6Li稳定同位素示踪了爆炸过程中放射性气溶胶粒子悬浮、沉积和在毛细管中扩散行为。实验结果表明：爆炸后100h，气溶胶粒子悬浮份额占10-5；沉积量占绝大多数，且各部位沉积量存在明显差异；即使在无压力推动下，仍明显观察到了气溶胶粒子在毛细管中的扩散，对于d25μm×2cm 毛细管通道而言，穿透率为1.5×10-10 / h。研究结果对于正确评估放射性气溶胶粒子在爆炸过程中的行为有一定的价值。 相似文献
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Jianheng Liu Tao Huang Yusen Zhang Tianxuan Zhao Xueni Zhao Wanying Chen Rui Zhang 《国家科学评论(英文版)》2021,8(6)
mRNA m5C, which has recently been implicated in the regulation of mRNA mobility, metabolism and translation, plays important regulatory roles in various biological events. Two types of m5C sites are found in mRNAs. Type I m5C sites, which contain a downstream G-rich triplet motif and are computationally predicted to be located at the 5′ end of putative hairpin structures, are methylated by NSUN2. Type II m5C sites contain a downstream UCCA motif and are computationally predicted to be located in the loops of putative hairpin structures. However, their biogenesis remains unknown. Here we identified NSUN6, a methyltransferase that is known to methylate C72 of tRNAThr and tRNACys, as an mRNA methyltransferase that targets Type II m5C sites. Combining the RNA secondary structure prediction, miCLIP, and results from a high-throughput mutagenesis analysis, we determined the RNA sequence and structural features governing the specificity of NSUN6-mediated mRNA methylation. Integrating these features into an NSUN6-RNA structural model, we identified an NSUN6 variant that largely loses tRNA methylation but retains mRNA methylation ability. Finally, we revealed a weak negative correlation between m5C methylation and translation efficiency. Our findings uncover that mRNA m5C is tightly controlled by an elaborate two-enzyme system, and the protein-RNA structure analysis strategy established may be applied to other RNA modification writers to distinguish the functions of different RNA substrates of a writer protein. 相似文献