高铁混凝土简支预应力箱梁施工技术研究

结合我国某高铁预应力混凝土简支箱梁采用后张法施工的过程,简要论述三项关键工序、高性能混凝土耐久性指标的保证措施、减小箱梁后期徐变的相关施工措施及注意要点,以确保满足高速铁路运营的安全性、高速度、高平顺性和舒适度.     

除盐水制备技术进展

介绍了几种水除盐技术(蒸馏、离子交换、电渗析、反渗透、电去离子和电吸附)的原理、发展及应用现状,分析了水除盐技术发展的整体脉络,并预测了发展前景.     

天基发射与载人登月初探

登月是载人航天向深空探测的延续，它与载人飞船工程相比，可靠性要求更高，工程规模更大，资金投入更多。结合国外登月历程和我国航天事业取得的重大成就，探讨了利用现有运载技术，分批次将登月飞船和航天员送入近地轨道，并在天基发射平台上进行组装发射，实现载人登月的设想；并就天基发射平台和天基发射方式进行了初步探讨。     

高流动性星型尼龙12的合成与表征

在均苯三甲酸的存在下,进行十二内酰胺的水解聚合,合成了四种不同臂长的三臂星型尼龙12,对产物的分子量进行了测定,并对其力学性能和流变行为进行了研究。结果表明,星型尼龙12的分子量随着均苯三甲酸含量的提高而降低,与相应分子量的线型尼龙12相比,星型尼龙12的拉伸强度和弯曲强度基本保持,冲击强度保持率在80%以上,断裂伸长...     

沙柳/聚乙烯醇新型水凝胶复合膜的制备及性能研究

采用湿法纺丝合成新型沙柳木粉(SPP)/聚乙烯醇(PVA)水凝胶复合膜(SPPM)。研究凝固浴时间、硫酸浓度对SPPM吸附Hg²⁺吸附量与力学性能的影响。采用扫描电镜(SEM)、比表面积和平均孔径、红外光谱(FT-IR)和X射线衍射(XRD)等手段分析SPPM的结构和吸附机理;采用热重(TG)对SPPM的热性能进行分析。结果表明:凝固浴时间为1h, H₂SO₄浓度为7%时最佳,吸附量为421mg/g。SPPM具有较好的孔道结构,吸附性能良好且可重复利用5次以上,并具有较大的比表面积以及良好的热稳定性。SPPM的Hg²⁺吸附过程符合伪二级动力学模型和Freundlich等温线模型。     

Creation and control of high-dimensional multi-partite classically entangled light

Vector beams, non-separable in spatial mode and polarisation, have emerged as enabling tools in many diverse applications, from communication to imaging. This a...     

The Regulatory Role of H19/miR-181a/ATG5 Signaling in Perinatal Nicotine Exposure-Induced Development of Neonatal Brain Hypoxic-Ischemic Sensitive Phenotype

Nicotine exposure either from maternal cigarette smoking or e-cigarette vaping is one of the most common risk factors for neurodevelopmental disease in offspring. Previous studies revealed that perinatal nicotine exposure programs a sensitive phenotype to neonatal hypoxic-ischemic encephalopathy (HIE) in postnatal life, yet the underlying mechanisms remain undetermined. The goal of the present study was to determine the regulatory role of H19/miR-181a/ATG5 signaling in perinatal nicotine exposure-induced development of neonatal brain hypoxic-ischemic sensitive phenotype. Nicotine was administered to pregnant rats via subcutaneous osmotic minipumps. All experiments were conducted in offspring pups at postnatal day 9 (P9). Perinatal nicotine exposure significantly enhanced expression of miR-181a but attenuated autophagy-related protein 5 (ATG5) mRNA and protein levels in neonatal brains. Of interest, miR-181a mimicking administration in the absence of nicotine exposure also produced dose-dependent increased hypoxia/ischemia (H/I)-induced brain injury associated with a decreased ATG5 expression, closely resembling perinatal nicotine exposure-mediated effects. Locked nucleic acid (LNA)-miR-181a antisense reversed perinatal nicotine-mediated increase in H/I-induced brain injury and normalized aberrant ATG5 expression. In addition, nicotine exposure attenuated a long non-coding RNA (lncRNA) H19 expression level. Knockdown of H19 via siRNA increased the miR-181a level and enhanced H/I-induced neonatal brain injury. In conclusion, the present findings provide a novel mechanism that aberrant alteration of the H19/miR-181a/AGT5 axis plays a vital role in perinatal nicotine exposure-mediated ischemia-sensitive phenotype in offspring and suggests promising molecular targets for intervention and rescuing nicotine-induced adverse programming effects in offspring.