基于暂态零模电流的配电网故障区段定位

为降低小电流接地系统通信过程中小波扰动(噪声)对暂态电流法的干扰,减小因采样频率增加造成的通信网络负担,解决故障两侧馈线终端不同步的问题,提出了一种小电流接地系统的故障区段定位方法.通过检测故障区段两侧的暂态零模电流,提取其中的极值,并计算其衰减程度,利用其极性进行辅助定位.数值仿真的结果验证了所提方法的有效性,该方法...     

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.     

TSP超前地质预报地震波反射特性研究

深埋隧道工程地质和水文地质条件复杂多变,盲目施工常会造成突水、突泥(涌砂)和塌方等安全事故,深入细致的超前地质预报工作是隧道信息化设计和施工的重要依据之一.以高风险岩溶隧道沪蓉西高速齐岳山隧道为工程背景,结合地震波传播理论和TSP超前地质预报实践,研究了岩溶隧道内断层破碎带,泥夹石充填型、软弱夹泥充填型、地下水充填型和无充填型溶洞,以及富水岩层的地震波反射特性;提出了以深度偏移为主要依据,并结合反射层图、反射事件表、纵横波速和岩体物性参数分析的预报方法,该方法可以有效提高TSP对断层破碎带、溶洞、和地下水的超前地质预报效果,对类似工程具有一定的借鉴意义.     

量表精度自动检定仪的研制

对应用图像识别技术进行量表精度检定的测量原理进行了理论分析,研究了成像系统的组成及参数选择、被测物图像的采集、图像的处理及相关算法等,并据此研制了量表精度自动检定系统。实际应用结果表明,该检定仪性能稳定,测量精度较高,可满足工业量表检定的要求。     

Direct fabrication of single-crystal-like structure using quasi-continuous-wave laser additive manufacturing

The synchronously periodic re-melting of molten pool was firstly introduced in additive manufacturing to promote the epitaxial growth of columnar structure using a novel quasi-continuous-wave(QCW)laser.The epitaxial growth of columnar structure was intensified and the single-crystal-like sample with highly oriented "zigzag" columnar grains was produced.The modified molten-pool geometry and the synchronously high-frequency re-melting of the molten pool contribute to the formation of singlecrystal-like structure.This work reports a new route to promote the continuously epitaxial growth of dendrites for fabrication of single-crystal-like sample.     

白铅矿在黄药体系中的浮选行为研究

用黄药作为白铅矿捕收剂时,需要对白铅矿进行硫化,硫化的最佳pH范围是8～10;碳链越长,对白铅矿的捕收效果越好;异构体黄药捕收能力较正构体要好;在不硫化的条件下,黄药能够浮选白铅矿,但浮选指标不高.     

铝及其合金的表面改性技术介绍

现代经济的高速发展对铝及其合金在硬度、耐蚀性和耐磨性以及功能性方面有了更高的要求。介绍了铝及其合金表面改性技术的发展情况,新技术的使用有效改善了铝及其合金的表面性能。     

某大型特种工程车液压系统故障本体构建

为实现某大型特种工程车液压系统故障知识的共享,提出利用本体进行故障建模。根据液压系统特点设计出本体,针对本体难以描述的复杂故障引进SWRL,建立SWRL规则,最后进行实例的推理,结果表明利用本体和SWRL可以实现故障表示和故障推理。     

环保型金属加工液的研究趋势

金属加工液作为机械加工过程中必不可少的部分和影响环境能源以及劳动者身体健康的重要因素而一直受到人们的关注。新型环保型金属加工液无庸置疑地成为了金属加工液研究方向上的未来趋势。