摘要：随着社会的发展,人们的生活水平的不断提高,对生态环境的要求也越来越高。功耗低、传输距离长的无线物联网通讯技术应时而生,为传统环保监测提供了一种全新的解决方案。利用LoRa与NB-IoT技术,设计了一种功耗低、传输距离长的无线物联网环境监控系统,利用LoRa与NB-IoT混和组网方案,可填补NBIoT服务年费昂贵及Lo Ra不能通过运营商网络传送数据的缺陷。传感器节点与汇聚节点应用LoRa控制模块实现长距离自组网通讯;网关节点选用LoRa转NB-IoT方案,将LoRa自组网内数据通过运营商网络送往云端,然后在云端实现实时动态显示和查询。检测结果显示,本文所设计的系统整体性能较平稳,可将获得的PM2.5浓度值、环境温度、环境湿度等信息数据存储和实时显示,然后同步上传至云端,具有较高的实际应用价值。

摘要：The residue curve maps are considered as a powerful tool for the preliminary design of reactive distillation. The residue curve maps of ethyl acetate synthesis reaction were calculated based on the pseudo-homogeneous rate-based kinetic model and the NRTL activity coefficient model. The results show that the unstable node branch emerges from the ethyl acetate/water edge, moving toward the chemical equilibrium surface with the increase of Damk ler value (D), and the node reaches the ternary reactive azeotrope when D→∞ eventually. Conceptual design for the ethyl acetate synthesis of reactive distillation based on the residue curve maps is presented at last.

摘要：目的探讨一种可在常温下操作、简便易行、效果好的穿支血管造影液配比。方法常温下用不同配比的乳胶、水、四氧化三铅混合液对穿支血管进行灌注,灌注后的标本肉眼观察及X线摄片,比较其效果。结果乳胶(ml):水(ml):四氧化三铅(g)以1∶1∶2的比例配制灌注效果好,肉眼及X线片可见清晰的小血管网。配比中加入广告色、墨水等小分子量色料的效果差,影响观察血管。结论乳胶-四氧化三铅液是简便易行的小血管造影剂,其最佳配比∶乳胶(ml):水(ml):四氧化三铅(g)为1∶1∶2。