Under the dual influence of the mining disturbance of the previous working face and the advanced mining of the working face,the roadway is prone to large deformation,failure,and rockburst.Roadway stabilization has alw...Under the dual influence of the mining disturbance of the previous working face and the advanced mining of the working face,the roadway is prone to large deformation,failure,and rockburst.Roadway stabilization has always significantly influenced deep mining safety.In this article we used the research background of the large deformation failure roadway of Fa-er Coal Mine in Guizhou Province of China to propose two control methods:bolt-cable-mesh+concrete blocks+directional energy-gathering blasting(BCM-CBDE method)and 1st Generation-Negative Poisson’s Ratio(1G NPR)cable+directional energy-gathering blasting+dynamic pressure stage support(πgirder+single hydraulic prop+retractable U steel)(NPR-DEDP method).Meantime,we compared the validity of the large deformation failure control method in a deep gob-side roadway based on theoretical analysis,numerical simulations,and field experiments.The results show that directional energy-gathering blasting can weaken the pressure acting on the concrete blocks.However,the vertical stress of the surrounding rock of the roadway is still concentrated in the entity coal side and the concrete blocks,showing a’bimodal’distribution.BCM-CBDE method cannot effectively control the stability of the roadway.NPR-DEDP method removed the concrete blocks.It shows using the 1G NPR cable with periodic slipping-sticking characteristics can adapt to repeated mining disturbances.The peak value of the vertical stress of the roadway is reduced and transferred to the deep part of the surrounding rock mass,which promotes the collapse of the gangue in the goaf and fills the goaf.The pressure of the roadway roof is reduced,and the gob-side roadway is fundamentally protected.Meantime,the dynamic pressure stage support method withπgirder+single hydraulic prop+retractable U steel as the core effectively protects the roadway from dynamic pressure impact when the main roof is periodically broken.After the on-site implementation of NPR-DEDP method,the deformation of the roadway is reduced by more than 45%,and the deformation rate is reduced by more than 50%.展开更多
社交媒体中,用户所发布的推文内容记录了与用户相关的各种信息。文字信息中涵盖了推文中包含的各种话题,以及时间和空间信息,从这些信息中分析出话题的时空演变情况具有十分重要的研究意义。针对推文数据,设计了一套可视分析流程来挖掘...社交媒体中,用户所发布的推文内容记录了与用户相关的各种信息。文字信息中涵盖了推文中包含的各种话题,以及时间和空间信息,从这些信息中分析出话题的时空演变情况具有十分重要的研究意义。针对推文数据,设计了一套可视分析流程来挖掘推文信息,通过用户交互的方式多角度地展示了推文话题的时空演变过程。首先,基于部分历史推文数据,通过DBSCAN(Density-Based Spatial Clustering of Applications with Noise)聚类算法,结合泰森多边形对全球地理空间进行区域划分;然后,针对用户查询搜索的兴趣话题,索引找到所有相关的推文内容,并将信息与聚类中心绑定;最后,通过设计的多个结合时序聚类算法和自适应算法的可视化视图来展示话题的时空演变过程。通过推特官网提供的API抓取存储的推文数据,并进行实验和分析,结果表明:改进的可视化视图自适应布局算法有效地解决了图形遮挡问题,完整展现了推文的时空演变模式;地理区域的划分以及可视化组件能够有效帮助研究人员分析推文的时空演变以及全球关注的热点话题分布。展开更多
全麻患者气管插管前常经历一段窒息时间,窒息时间越长,低氧血症的发生率越高,其程度也越严重,诱导前以各种方式进行预充氧以延长窒息“安全时限”意义重大。湿化高流量鼻导管通气(humidified high flow nasal cannula,HFNC)是一种新型...全麻患者气管插管前常经历一段窒息时间,窒息时间越长,低氧血症的发生率越高,其程度也越严重,诱导前以各种方式进行预充氧以延长窒息“安全时限”意义重大。湿化高流量鼻导管通气(humidified high flow nasal cannula,HFNC)是一种新型无创通气技术,通过鼻导管将加温、湿化的高流量气体输送给患者,维持相对恒定的FiO_(2),可进行正压通气,改善氧合,广泛应用于新生儿科、ICU、急诊科等,近几年HFNC在窒息氧合领域取得重大突破,该技术不仅延长了窒息氧合时间,还可清除CO_(2),兼具通气和换气功能,已成功应用于全麻气管插管期。本文将HFNC在全麻气管插管诱导中的应用进展进行综述,拟为临床工作提供依据。展开更多
The nicotinic acetylcholine receptors （nAchRs） are cholinergic receptors that form ligand-gated ion channels by ifve subunits in insect and vertebrate nervous systems. The insect nAChR is the molecular target of a c...The nicotinic acetylcholine receptors （nAchRs） are cholinergic receptors that form ligand-gated ion channels by ifve subunits in insect and vertebrate nervous systems. The insect nAChR is the molecular target of a class of insecticides, neonicotinoids. Here, we identiifed and cloned 11 candidate nAChR subunit genes in Acyrthosiphon pisum using genome-based bioinformatics combined modern molecular techniques. Most A. pisum nAChRs including α1, α2, α3, α4, α6, α8, and β1 show highly sequence identities with the counterparts of other insects examined. Expression proifles analysis showed that all subunit genes were expressed in adult head. At least two subunits have alternative splicing that obviously increase A. pisum nicotinic receptor diversity. This study will be invaluable for exploring the molecular mechanisms of neonicotinoid-like insecticides in sucking pests, and for ultimately establishing the screening platform of novel insecticides.展开更多
Highly efficient phosphorescent white organic light-emitting diodes （WOLEDs） with stable emission spectra are successfully fabricated by using an RGB three-color separately monochromatic emission layer （EML） struc...Highly efficient phosphorescent white organic light-emitting diodes （WOLEDs） with stable emission spectra are successfully fabricated by using an RGB three-color separately monochromatic emission layer （EML） struc- ture. The EML consists of a sequence of bis（2-methyldibenzo[f, h]quinoxaline） （acetylacetonate） iridium （Ⅲ） （Ir（MDQ）2（acac）） doped tris（4-carbazoyl-9-ylphenyl）amine （TCTA） as the red emission layer, iridium, tris（2- phenylpyidine）（Ir（ppy）3） doped TCTA as the green emission layer and iridium（Ill） Ibis（4, 6-difuorophenyl）- pyridinato-N, C2＇]picolinate （FIrpic） doped a mixed-host of TCTA and tris（4-carbazoyl-9-ylphenyl）amine （26DCz PPy） as the blue emission layer. Without using any out-coupling techniques, the resulting WOLEDs achieve a power efficiency of 421m/W at lOO cd/m2, and 34 lm/W at 1000 cd/m2. The WOLEDs also show excellent spec- trum stability with bias voltages, remaining the Commission Internationale de L＇Eclairage coordinates at （0.44, 0.43） from 1000 cd/m2 to 10000 cd/m2 and the color rendering index is as high as over 80. We contribute the sta- ble emission spectrum to the RGB separate EML structure that successfully suppresses the undesired competition between host-guest energy transfer and direct exciton formation on emissive dopants by effectively controlling the position of exciton recombination region.展开更多
基金funded by National Natural Science Foundation of China(52074300)Yueqi Young Scholars Project of China University of Mining and Technology Beijing(2602021RC84)+1 种基金China University of Mining and Technology(Beijing)fundamental scientific research funds—Doctoral students Top-notch Innovative Talents Fostering Funds(BBJ2023047)Guizhou Provincial Science and Technology Planning Project([2020]2Y030)。
文摘Under the dual influence of the mining disturbance of the previous working face and the advanced mining of the working face,the roadway is prone to large deformation,failure,and rockburst.Roadway stabilization has always significantly influenced deep mining safety.In this article we used the research background of the large deformation failure roadway of Fa-er Coal Mine in Guizhou Province of China to propose two control methods:bolt-cable-mesh+concrete blocks+directional energy-gathering blasting(BCM-CBDE method)and 1st Generation-Negative Poisson’s Ratio(1G NPR)cable+directional energy-gathering blasting+dynamic pressure stage support(πgirder+single hydraulic prop+retractable U steel)(NPR-DEDP method).Meantime,we compared the validity of the large deformation failure control method in a deep gob-side roadway based on theoretical analysis,numerical simulations,and field experiments.The results show that directional energy-gathering blasting can weaken the pressure acting on the concrete blocks.However,the vertical stress of the surrounding rock of the roadway is still concentrated in the entity coal side and the concrete blocks,showing a’bimodal’distribution.BCM-CBDE method cannot effectively control the stability of the roadway.NPR-DEDP method removed the concrete blocks.It shows using the 1G NPR cable with periodic slipping-sticking characteristics can adapt to repeated mining disturbances.The peak value of the vertical stress of the roadway is reduced and transferred to the deep part of the surrounding rock mass,which promotes the collapse of the gangue in the goaf and fills the goaf.The pressure of the roadway roof is reduced,and the gob-side roadway is fundamentally protected.Meantime,the dynamic pressure stage support method withπgirder+single hydraulic prop+retractable U steel as the core effectively protects the roadway from dynamic pressure impact when the main roof is periodically broken.After the on-site implementation of NPR-DEDP method,the deformation of the roadway is reduced by more than 45%,and the deformation rate is reduced by more than 50%.
文摘社交媒体中,用户所发布的推文内容记录了与用户相关的各种信息。文字信息中涵盖了推文中包含的各种话题,以及时间和空间信息,从这些信息中分析出话题的时空演变情况具有十分重要的研究意义。针对推文数据,设计了一套可视分析流程来挖掘推文信息,通过用户交互的方式多角度地展示了推文话题的时空演变过程。首先,基于部分历史推文数据,通过DBSCAN(Density-Based Spatial Clustering of Applications with Noise)聚类算法,结合泰森多边形对全球地理空间进行区域划分;然后,针对用户查询搜索的兴趣话题,索引找到所有相关的推文内容,并将信息与聚类中心绑定;最后,通过设计的多个结合时序聚类算法和自适应算法的可视化视图来展示话题的时空演变过程。通过推特官网提供的API抓取存储的推文数据,并进行实验和分析,结果表明:改进的可视化视图自适应布局算法有效地解决了图形遮挡问题,完整展现了推文的时空演变模式;地理区域的划分以及可视化组件能够有效帮助研究人员分析推文的时空演变以及全球关注的热点话题分布。
文摘全麻患者气管插管前常经历一段窒息时间,窒息时间越长,低氧血症的发生率越高,其程度也越严重,诱导前以各种方式进行预充氧以延长窒息“安全时限”意义重大。湿化高流量鼻导管通气(humidified high flow nasal cannula,HFNC)是一种新型无创通气技术,通过鼻导管将加温、湿化的高流量气体输送给患者,维持相对恒定的FiO_(2),可进行正压通气,改善氧合,广泛应用于新生儿科、ICU、急诊科等,近几年HFNC在窒息氧合领域取得重大突破,该技术不仅延长了窒息氧合时间,还可清除CO_(2),兼具通气和换气功能,已成功应用于全麻气管插管期。本文将HFNC在全麻气管插管诱导中的应用进展进行综述,拟为临床工作提供依据。
基金supported by the National 973 Program of China(2012CB114104)the Beijing Natural Science FoundationChina (6132028)
文摘The nicotinic acetylcholine receptors （nAchRs） are cholinergic receptors that form ligand-gated ion channels by ifve subunits in insect and vertebrate nervous systems. The insect nAChR is the molecular target of a class of insecticides, neonicotinoids. Here, we identiifed and cloned 11 candidate nAChR subunit genes in Acyrthosiphon pisum using genome-based bioinformatics combined modern molecular techniques. Most A. pisum nAChRs including α1, α2, α3, α4, α6, α8, and β1 show highly sequence identities with the counterparts of other insects examined. Expression proifles analysis showed that all subunit genes were expressed in adult head. At least two subunits have alternative splicing that obviously increase A. pisum nicotinic receptor diversity. This study will be invaluable for exploring the molecular mechanisms of neonicotinoid-like insecticides in sucking pests, and for ultimately establishing the screening platform of novel insecticides.
基金Supported by the Science Fund for Creative Research Groups of the National Natural Science Foundation of China under Grant No 20921061, the National Natural Science Foundation of China under Grant Nos 50973104, 60906020, 21161160442, 61036007 and 60937001, the Ministry of Science and Technology of China under Grant Nos 2009CB623604 and 2009CB930603, and the Foundation of Jilin Research Council under Grant No 2012ZDGG001, 20090127 and 201105028.
文摘Highly efficient phosphorescent white organic light-emitting diodes （WOLEDs） with stable emission spectra are successfully fabricated by using an RGB three-color separately monochromatic emission layer （EML） struc- ture. The EML consists of a sequence of bis（2-methyldibenzo[f, h]quinoxaline） （acetylacetonate） iridium （Ⅲ） （Ir（MDQ）2（acac）） doped tris（4-carbazoyl-9-ylphenyl）amine （TCTA） as the red emission layer, iridium, tris（2- phenylpyidine）（Ir（ppy）3） doped TCTA as the green emission layer and iridium（Ill） Ibis（4, 6-difuorophenyl）- pyridinato-N, C2＇]picolinate （FIrpic） doped a mixed-host of TCTA and tris（4-carbazoyl-9-ylphenyl）amine （26DCz PPy） as the blue emission layer. Without using any out-coupling techniques, the resulting WOLEDs achieve a power efficiency of 421m/W at lOO cd/m2, and 34 lm/W at 1000 cd/m2. The WOLEDs also show excellent spec- trum stability with bias voltages, remaining the Commission Internationale de L＇Eclairage coordinates at （0.44, 0.43） from 1000 cd/m2 to 10000 cd/m2 and the color rendering index is as high as over 80. We contribute the sta- ble emission spectrum to the RGB separate EML structure that successfully suppresses the undesired competition between host-guest energy transfer and direct exciton formation on emissive dopants by effectively controlling the position of exciton recombination region.
