基于NR-Transformer的集群作业运行时间预测

高性能集群的作业调度通常使用作业调度系统来实现,准确填写作业运行时间能在很大程度上提升作业调度效率。现有的研究通常使用机器学习的预测方式,在预测精度和实用性上还存在一定的提升空间。为了进一步提高集群作业运行时间预测的准确率,考虑先对集群作业日志进行聚类,将作业类别信息添加到作业特征中,再使用基于注意力机制的NR-Transformer网络对作业日志数据建模和预测。在数据处理上,根据与预测目标的相关性、特征的完整性和数据的有效性,从历史日志数据集中筛选出7维特征,并按作业运行时间的长度将其划分为多个作业集,再对各作业集分别进行训练和预测。实验结果表明,相比于传统机器学习和BP神经网络,时序神经网络结构有更好的预测性能,其中NR-Transformer在各作业集上都有较好的性能。     

Having a Same Type IIS Enzyme’s Restriction Site on Guide RNA Sequence Does Not Affect Golden Gate (GG) Cloning and Subsequent CRISPR/Cas Mutagenesis

Golden gate/modular cloning facilitates faster and more efficient cloning by utilizing the unique features of the type IIS restriction enzymes. However, it is known that targeted insertion of DNA fragment(s) must not include internal type IIS restriction recognition sites. In the case of cloning CRISPR constructs by using golden gate (GG) cloning, this narrows down the scope of guide RNA (gRNA) picks because the selection of a good gRNA for successful genome editing requires some obligation of fulfillment, and it is unwanted if a good gRNA candidate cannot be picked only because it has an internal type IIS restriction recognition site. In this article, we have shown that the presence of a type IIS restriction recognition site in a gRNA does not affect cloning and subsequent genome editing. After each step of GG reactions, correct insertions of gRNAs were verified by colony color and restriction digestion and were further confirmed by sequencing. Finally, the final vector containing a Cas12a nuclease and four gRNAs was used for Agrobacterium-mediated citrus cell transformation. Sequencing of PCR amplicons flanking gRNA-2 showed a substitution (C to T) mutation in transgenic plants. The knowledge derived from this study could widen the scope of GG cloning, particularly of gRNAs selection for GG-mediated cloning into CRISPR vectors.     

某砌体房屋底层大空间改造设计

已有砖砌体房屋底层常因功能改变而需要更大的使用空间,部分承重墙体的抽除必将导致传力途径的改变,故需对原有结构进行加固。阐述了托换技术在房屋改造加固中的应用,同时对托换技术的各设计阶段,包括基础设计、结构设计等作了分析。     

A Review of Toxicity Mechanism Studies of Electronic Cigarettes on Respiratory System

Electronic cigarettes (e-cigarettes) have attracted much attention as a new substitute for conventional cigarettes. E-cigarettes are first exposed to the respiratory system after inhalation, and studies on the toxicity mechanisms of e-cigarettes have been reported. Current research shows that e-cigarette exposure may have potentially harmful effects on cells, animals, and humans, while the safety evaluation of the long-term effects of e-cigarette use is still unknown. Similar but not identical to conventional cigarettes, the toxicity mechanisms of e-cigarettes are mainly manifested in oxidative stress, inflammatory responses, and DNA damage. This review will summarize the toxicity mechanisms and signal pathways of conventional cigarettes and e-cigarettes concerning the respiratory system, which could give researchers a better understanding and direction on the effects of e-cigarettes on our health.     

梁结构振动支承约束反力控制

支承或连接构件对梁结构的动力学性能有至关重要影响,必须保证其在振动过程中不发生破坏或者失效.通过合理设计和布局附加弹性支承可以实现对这些重要连接构件所承受约束反力的控制.应用微分变换法推导含附加支承的梁结构支承约束反力及其对于附加支承位置和刚度的灵敏度表达式,并通过优化设计附加支承位置和刚度实现具有弹性约束端的简支梁结...     

汽车悬架用弹簧钢55SiCr制备技术的研究进展

悬架弹簧钢是汽车悬架系统的重要部件,研发高性能汽车悬架弹簧钢制备技术对于推动特殊钢材料的国产化有着重要的意义。从洁净度控制、组织性能调控和表面脱碳控制3个方面介绍近年来汽车悬架弹簧钢55SiCr制备技术的最新进展。在洁净度控制上,对弹簧钢中夹杂物的控制方向、脱氧工艺、精炼渣和耐火材料等相关研究进行介绍。在组织性能调控中,重点介绍作者所在研究所在悬架弹簧钢55SiCr热处理工艺改进与优化上的探索,比较了淬火-回火、等温淬火和淬火-配分工艺对悬架弹簧钢55SiCr力学性能的影响。表面脱碳控制的相关研究表明,在进行热处理或热加工的过程中,应尽量避免在低于弹簧钢奥氏体/铁素体转变温度(约800℃)附近停留,虽然较高的温度有利于避免全脱碳,但是出于晶粒粗化、能耗和氧化等方面的考虑,热处理温度不宜高于1 100℃。     

铬污染的微生物吸附技术研究进展

近年来,铬在工业生产中得到了广泛的应用,随之而来的含铬污染物对周围环境造成严重的污染和破坏,铬污染的修复已成为亟待解决的环境问题.微生物在铬污染的生物修复中发挥着重要的作用.它因铬污染修复过程中环保有效,安全可靠且无二次污染等优点,引起了相关学者们的广泛关注.首先简述了铬污染危害及传统处理技术,重点综述了微生物作为生物...     

EPON+LAN与EPON+EoC接入方式的选择

介绍了EPON系统与EoC的组成及原理,以此引申出EPON+LAN、EPON+EoC的技术模型,通过EPON+LAN与EPON+EoC的技术对比,根据其优缺点,结合双向网络建设的实际情况,分析双向网络改造中对EPON+LAN与EPON+EoC接入方式的选择。     

硝胺单元推进剂燃速的理论计算

在火炸药燃速预估模型的基础上，分析了硝胺单质炸药的热分解特征，提出了硝胺单元推进剂燃烧初期热分解机理的有关假说，并将气相分解产物分类为氧化剂、还原剂、可裂解自由基和惰性基团，进而提出了硝胺单元推进剂燃速和压力指数公式．运用该公式可从化学结构出发计算硝胺单质炸药的燃速和压力指数．通过十种不同类型硝胺单元推进剂燃速的实际计算表明，理论值与实测值十分一致．由此讨论了影响硝胺单质炸药燃速与燃速压力指数的化学结构因素．