在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制...在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。展开更多
The seismic data from western China is very noisy. Two main reasons are static corrections and low S/N ratio problems. By seismic data processing and study these problems have been effectively solved by iterating the ...The seismic data from western China is very noisy. Two main reasons are static corrections and low S/N ratio problems. By seismic data processing and study these problems have been effectively solved by iterating the static corrections and improving the S/N ratio for pre-stack seismic data. Suppression and elimination of various other distortions has been implemented as well. Due to the fact that the S/N ratio is improved, the resolution of the seismic data is also improved.展开更多
针对污水处理厂尾水TN去除问题,采用16S r DNA克隆文库法,探究了3DBER-S(三维电极生物膜耦合硫自养脱氮工艺)的强化脱氮机制及其菌群特征.结果表明,I(电流)和HRT(水力停留时间)对3DEBR-S中氢自养和硫自养反硝化作用所占比例的影响较大,...针对污水处理厂尾水TN去除问题,采用16S r DNA克隆文库法,探究了3DBER-S(三维电极生物膜耦合硫自养脱氮工艺)的强化脱氮机制及其菌群特征.结果表明,I(电流)和HRT(水力停留时间)对3DEBR-S中氢自养和硫自养反硝化作用所占比例的影响较大,但对脱氮效率影响不显著.当进水C/N〔ρ(CODCr)/ρ(TN)〕为1、ρ(NO3--N)为35 mg/L、I为300 m A、HRT为4 h时,NO3--N和TN去除率可分别稳定在80%和74%以上.16S r DNA克隆文库结果显示,反应器中β变形菌纲为优势菌群,占47.89%〔以OUT(操作单元)计〕.在β变形菌纲中,与具有反硝化功能的陶厄氏菌属(Thauera)相似的细菌所占比例最大,为52.94%;与可分别利用硫和氢为电子供体进行反硝化脱氮的硫杆菌属(Thiobacillus)和食酸菌属(Acidovorax)相似的细菌分别占17.65%和14.71%.3DBER-S中存在异养联合氢自养和硫自养反硝化协同去除硝酸盐氮的作用,可为反硝化脱氮提供充足的电子供体,节约了有机碳源消耗,并保证了稳定高效的脱氮效果.展开更多
基于挪威船级社《Fatigue Assessment of Ship Structures》(2010),考虑由装载与卸载而引起的低周疲劳,对FPSO船体易发生疲劳破坏的部位进行疲劳寿命评估。采用简化分析法计算由波浪弯矩产生的全局应力与内外水压力产生的局部应力,以及...基于挪威船级社《Fatigue Assessment of Ship Structures》(2010),考虑由装载与卸载而引起的低周疲劳,对FPSO船体易发生疲劳破坏的部位进行疲劳寿命评估。采用简化分析法计算由波浪弯矩产生的全局应力与内外水压力产生的局部应力,以及在装卸载过程中产生的应力范围,然后通过S-N曲线计算结构的疲劳寿命。结果表明,不同校核部位的低周疲劳对其疲劳寿命的影响不同,而且这种影响与低周疲劳的次数有关,最后分析产生这些结果的原因。展开更多
Laser shock peening （LSP） is a novel effective surface treatment method to improve the fatigue performance of turbine blades. To study the effect of LSP on combined low- and high-cycle fatigue （CCF） life of turbin...Laser shock peening （LSP） is a novel effective surface treatment method to improve the fatigue performance of turbine blades. To study the effect of LSP on combined low- and high-cycle fatigue （CCF） life of turbine blades, the CCF tests were conducted at elevated temperatures on two types of full-scale turbine blades, which were made of K403 by casting and GH4133B by forging. Probabilistic analysis was conducted to find out the effect of LSP on fatigue life of those two kinds of blades. The results indicated that LSP extended the CCF life of both casting blades and forging blades obviously, and the effect of LSP on casting blades was more evident; besides, a threshold vibration stress existed for both casting blades and forging blades, and the CCF life tended to be extended by LSP only when the vibration stress was below the threshold vibra- tion stress. Further study of fractography was also conducted, indicating that due to the presence of compressive residual stress and refined grains induced by LSP, the crack initiation sources in LSP blades were obviously less, and the life of LSP blades was also longer; since the compressive residual stress was released by plastic deformation, LSP had no effect or adverse effect on CCF life of blade when the vibration stress of blade was above the threshold vibration stress.展开更多
文摘在基于Mesh-under的IPv6低功耗无线个域网(IPv6over low-power wireless personal area networks,6LoWPAN)中,针对传输路径上中间节点重传缓存溢出导致重传数据分片丢失,造成网络性能下降等问题,提出一种基于Mesh-under的备用缓存机制。本文所提机制根据传输路径上各节点重传缓存使用情况及数据分片剩余跳数等信息,设置动态重传缓存门限,并为超过该门限的节点从其邻居节点中挑选合适的备用缓存节点,从而完成数据分片的缓存与重传过程,达到均衡使用各节点重传缓存的目的。结果表明,所提机制能够有效避免重传缓存溢出,减小网络能耗,同时进一步提高目的端重组成功率。
文摘The seismic data from western China is very noisy. Two main reasons are static corrections and low S/N ratio problems. By seismic data processing and study these problems have been effectively solved by iterating the static corrections and improving the S/N ratio for pre-stack seismic data. Suppression and elimination of various other distortions has been implemented as well. Due to the fact that the S/N ratio is improved, the resolution of the seismic data is also improved.
文摘针对污水处理厂尾水TN去除问题,采用16S r DNA克隆文库法,探究了3DBER-S(三维电极生物膜耦合硫自养脱氮工艺)的强化脱氮机制及其菌群特征.结果表明,I(电流)和HRT(水力停留时间)对3DEBR-S中氢自养和硫自养反硝化作用所占比例的影响较大,但对脱氮效率影响不显著.当进水C/N〔ρ(CODCr)/ρ(TN)〕为1、ρ(NO3--N)为35 mg/L、I为300 m A、HRT为4 h时,NO3--N和TN去除率可分别稳定在80%和74%以上.16S r DNA克隆文库结果显示,反应器中β变形菌纲为优势菌群,占47.89%〔以OUT(操作单元)计〕.在β变形菌纲中,与具有反硝化功能的陶厄氏菌属(Thauera)相似的细菌所占比例最大,为52.94%;与可分别利用硫和氢为电子供体进行反硝化脱氮的硫杆菌属(Thiobacillus)和食酸菌属(Acidovorax)相似的细菌分别占17.65%和14.71%.3DBER-S中存在异养联合氢自养和硫自养反硝化协同去除硝酸盐氮的作用,可为反硝化脱氮提供充足的电子供体,节约了有机碳源消耗,并保证了稳定高效的脱氮效果.
文摘基于挪威船级社《Fatigue Assessment of Ship Structures》(2010),考虑由装载与卸载而引起的低周疲劳,对FPSO船体易发生疲劳破坏的部位进行疲劳寿命评估。采用简化分析法计算由波浪弯矩产生的全局应力与内外水压力产生的局部应力,以及在装卸载过程中产生的应力范围,然后通过S-N曲线计算结构的疲劳寿命。结果表明,不同校核部位的低周疲劳对其疲劳寿命的影响不同,而且这种影响与低周疲劳的次数有关,最后分析产生这些结果的原因。
基金This work was supported by National Natural Science Foundation of China （Grant Nos. 11602010 and 51505018）.
文摘Laser shock peening （LSP） is a novel effective surface treatment method to improve the fatigue performance of turbine blades. To study the effect of LSP on combined low- and high-cycle fatigue （CCF） life of turbine blades, the CCF tests were conducted at elevated temperatures on two types of full-scale turbine blades, which were made of K403 by casting and GH4133B by forging. Probabilistic analysis was conducted to find out the effect of LSP on fatigue life of those two kinds of blades. The results indicated that LSP extended the CCF life of both casting blades and forging blades obviously, and the effect of LSP on casting blades was more evident; besides, a threshold vibration stress existed for both casting blades and forging blades, and the CCF life tended to be extended by LSP only when the vibration stress was below the threshold vibra- tion stress. Further study of fractography was also conducted, indicating that due to the presence of compressive residual stress and refined grains induced by LSP, the crack initiation sources in LSP blades were obviously less, and the life of LSP blades was also longer; since the compressive residual stress was released by plastic deformation, LSP had no effect or adverse effect on CCF life of blade when the vibration stress of blade was above the threshold vibration stress.
