Based on the nonlinear Mohr-Coulomb failure criterion and an associated flow rule,a kinematic admissible velocity field of failure mechanism of the 2-layer soil above a shallow horizontal strip anchor plate is constru...Based on the nonlinear Mohr-Coulomb failure criterion and an associated flow rule,a kinematic admissible velocity field of failure mechanism of the 2-layer soil above a shallow horizontal strip anchor plate is constructed.The ultimate pull-out force and its corresponding failure mechanism through the upper bound limit analysis according to a variation principle are deduced.When the 2-layer overlying soil is degraded into single-layer soil,the model of ultimate pullout force could also be degraded into the model of single-layer soil.And the comparison between results of single-layer soil variation method and those calculated by rigid limit analysis method proves the correctness of our method.Based on that,the influence of changes of geotechnical parameters on ultimate pullout forces and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are analyzed.The results show that the ultimate pull-out force and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are affected by the nonlinear geotechnical parameters greatly.Thus,it is very important to obtain the accurate geotechnical parameters of 2-layer soil for the evaluation of the ultimate pullout capacity of the anchor plate.展开更多
This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried o...This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried out from the two nearest days (previous and following of quietest day). The study uses International Reference Ionosphere (IRI) for ionosphere modeling. The located station is Ouagadougou, in West Africa. Solar minimum of phase 22 is considered in this study. Using three core principles of ionosphere modeling under IRI running conditions, the study enables to carry out Peak of electron density in F2-layer values during the quietest days of the characteristic months for the four different seasons. These parameters are compared to those of the previous and the following of the quietest days (the day before and following each quietest selected day) at the same hour. The knowledge of NmF2 values at the quietest days and at the two nearest days enables to calculate the relative error that can be made on this parameter. This calculation highlights insignificant relative errors. This means that NmF2 values at the two nearest days of each quietest day on solar minimum can be used for simulating the quietest days’ behavior. NmF2 values obtained by running IRI model have good correlation with those carried out by Thermosphere-Ionosphere-Electrodynamics-General Circulation Model (TIEGCM).展开更多
Ionosphere layer is the atmosphere region which reflects radio waves for telecommunication. The density in particles in this layer influences the quality of communication. This study deals with the effects of Total El...Ionosphere layer is the atmosphere region which reflects radio waves for telecommunication. The density in particles in this layer influences the quality of communication. This study deals with the effects of Total Electron Contents (TEC) on the critical frequency of radio waves in the F2-layer. Total Electron Contents parameter symbolizes electron bulk surface density in ionosphere layer. Above critical frequency value in F2 layer (foF2), radio waves pass through ionosphere. The knowledge of this value enables to calibrate transmission frequencies. In this study, we consider TEC effects on foF2 under quiet time conditions during the maximum and the minimum of solar cycle 22, at Ouagadougou station, in West Africa. The study also considers the effects of seasons and the hourly variability of TEC and foF2. This work shows winter anomaly on foF2 and TEC on minimum and maximum of solar cycle phase respectively. Running International Reference Ionosphere (IRI) model enables to carry out the effects of TEC on foF2 by use of their monthly average values. This leads to a new approach to calibrate radio transmitters.展开更多
等级保护2.0(以下简称“等保2.0”)对数据中心信息安全架构提出了合规与技术要求。文章构建四层联动架构模型,涵盖网络安全、计算环境、应用数据与安全运营4个层面,通过引入零信任访问控制、虚拟化隔离机制、数据全生命周期防护及安全...等级保护2.0(以下简称“等保2.0”)对数据中心信息安全架构提出了合规与技术要求。文章构建四层联动架构模型,涵盖网络安全、计算环境、应用数据与安全运营4个层面,通过引入零信任访问控制、虚拟化隔离机制、数据全生命周期防护及安全编排自动化响应(Security Orchestration Automation and Response,SOAR)机制,提出了一套面向等保2.0的优化实施方案。实验结果表明,优化架构在检测率、响应效率、资源占用等关键指标上相较传统架构均有显著提升。因此,优化架构具备良好的工程适配性与合规落地能力。展开更多
Multifunctional（poly（diallyldimethyl ammonium chloride）/sodium poly（4-styrene sulfonate）） n（（PDDA/PSS） n） thin films were fabricated by layer-by-layer assembled on the glass substrate.The monolayer silica na...Multifunctional（poly（diallyldimethyl ammonium chloride）/sodium poly（4-styrene sulfonate）） n（（PDDA/PSS） n） thin films were fabricated by layer-by-layer assembled on the glass substrate.The monolayer silica nanoparticles were prepared on the（PDDA/PSS） n films.The SiO 2-polyelectrolyte coatings exhibit antireflection properties with low refractive index（as low as 1.22）.Interestingly,wavelengths of maximum transmittance could be well tailored by simply changing the particle size of SiO 2.A maximum transmittance of 97.03% in the visible spectral range is achieved for the particle size of 100 nm SiO 2 films.The coatings also show excellent mechanical stability and good adhesion to substrates.The easy availability of the raw materials and simplicity of the fabrication method for such films might make them be potentially useful for various applications.展开更多
基金Project (51478477) supported by the National Natural Science Foundation of ChinaProject (2016CX012) supported by the Innovation-Driven Project of Central South University,ChinaProject (2014122006) supported by the Guizhou Provincial Department of Transportation Foundation,China
文摘Based on the nonlinear Mohr-Coulomb failure criterion and an associated flow rule,a kinematic admissible velocity field of failure mechanism of the 2-layer soil above a shallow horizontal strip anchor plate is constructed.The ultimate pull-out force and its corresponding failure mechanism through the upper bound limit analysis according to a variation principle are deduced.When the 2-layer overlying soil is degraded into single-layer soil,the model of ultimate pullout force could also be degraded into the model of single-layer soil.And the comparison between results of single-layer soil variation method and those calculated by rigid limit analysis method proves the correctness of our method.Based on that,the influence of changes of geotechnical parameters on ultimate pullout forces and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are analyzed.The results show that the ultimate pull-out force and failure mechanism of a shallow horizontal strip anchor with the 2-layer soil above are affected by the nonlinear geotechnical parameters greatly.Thus,it is very important to obtain the accurate geotechnical parameters of 2-layer soil for the evaluation of the ultimate pullout capacity of the anchor plate.
文摘This study deals with Peak of electron density in F2-layer sensibility scale during quiet time on solar minimum. Peaks of electron density in F2-layer (NmF2) values at the quietest days are compared to those carried out from the two nearest days (previous and following of quietest day). The study uses International Reference Ionosphere (IRI) for ionosphere modeling. The located station is Ouagadougou, in West Africa. Solar minimum of phase 22 is considered in this study. Using three core principles of ionosphere modeling under IRI running conditions, the study enables to carry out Peak of electron density in F2-layer values during the quietest days of the characteristic months for the four different seasons. These parameters are compared to those of the previous and the following of the quietest days (the day before and following each quietest selected day) at the same hour. The knowledge of NmF2 values at the quietest days and at the two nearest days enables to calculate the relative error that can be made on this parameter. This calculation highlights insignificant relative errors. This means that NmF2 values at the two nearest days of each quietest day on solar minimum can be used for simulating the quietest days’ behavior. NmF2 values obtained by running IRI model have good correlation with those carried out by Thermosphere-Ionosphere-Electrodynamics-General Circulation Model (TIEGCM).
文摘Ionosphere layer is the atmosphere region which reflects radio waves for telecommunication. The density in particles in this layer influences the quality of communication. This study deals with the effects of Total Electron Contents (TEC) on the critical frequency of radio waves in the F2-layer. Total Electron Contents parameter symbolizes electron bulk surface density in ionosphere layer. Above critical frequency value in F2 layer (foF2), radio waves pass through ionosphere. The knowledge of this value enables to calibrate transmission frequencies. In this study, we consider TEC effects on foF2 under quiet time conditions during the maximum and the minimum of solar cycle 22, at Ouagadougou station, in West Africa. The study also considers the effects of seasons and the hourly variability of TEC and foF2. This work shows winter anomaly on foF2 and TEC on minimum and maximum of solar cycle phase respectively. Running International Reference Ionosphere (IRI) model enables to carry out the effects of TEC on foF2 by use of their monthly average values. This leads to a new approach to calibrate radio transmitters.
文摘等级保护2.0(以下简称“等保2.0”)对数据中心信息安全架构提出了合规与技术要求。文章构建四层联动架构模型,涵盖网络安全、计算环境、应用数据与安全运营4个层面,通过引入零信任访问控制、虚拟化隔离机制、数据全生命周期防护及安全编排自动化响应(Security Orchestration Automation and Response,SOAR)机制,提出了一套面向等保2.0的优化实施方案。实验结果表明,优化架构在检测率、响应效率、资源占用等关键指标上相较传统架构均有显著提升。因此,优化架构具备良好的工程适配性与合规落地能力。
基金Supported by the National Science Foundation of China(21174108)the Fundamental Research Funds for the Central Universities(20102020201000017)
文摘Multifunctional（poly（diallyldimethyl ammonium chloride）/sodium poly（4-styrene sulfonate）） n（（PDDA/PSS） n） thin films were fabricated by layer-by-layer assembled on the glass substrate.The monolayer silica nanoparticles were prepared on the（PDDA/PSS） n films.The SiO 2-polyelectrolyte coatings exhibit antireflection properties with low refractive index（as low as 1.22）.Interestingly,wavelengths of maximum transmittance could be well tailored by simply changing the particle size of SiO 2.A maximum transmittance of 97.03% in the visible spectral range is achieved for the particle size of 100 nm SiO 2 films.The coatings also show excellent mechanical stability and good adhesion to substrates.The easy availability of the raw materials and simplicity of the fabrication method for such films might make them be potentially useful for various applications.
