A basic 7-level MLI topology is developed and the same is extended to the 9-level then further increased to 17-levels.The developed structure minimizes the component’s count and size to draw out the system economy.De...A basic 7-level MLI topology is developed and the same is extended to the 9-level then further increased to 17-levels.The developed structure minimizes the component’s count and size to draw out the system economy.Despite the various advantages of MLIs,efficiency and reliability play a major role since the usage of components is higher for getting a low Total Harmonics Distortion(THD)value.This becomes a major challenge incorporated in boosting the efficiency without affecting the THD value.Various parametric observations are done and realized for the designed 9-level and 17-level MLI,being the Total Standing Voltage(TSV),efficiency,cost function per level count,and power loss.The respective parameters are compared with several existing and modern circuits and found to be effective in their performance.A novel single-phase 17-level asymmetrical Multi-Level Inverter(MLI)topology is developed to reduce the number of overall components.The developed topology generates 17-levels by using unequal DC sources.The developed MLI is proved under various tests con-ducted experimentally for the various loads like resistive,inductive,and combinational loads.A detailed comparison is done on several factors and represented graphically represented.Further,the proposed design provides a less TSV value is 6 V_(dc),efficiency is 94.21%and cost factor per level CF/L value for both values ofαis 2.01 and 2.05 and devices count with a low THD value 41.4%with respectively.展开更多
Many staircases in reinforced concrete (RC) frame structures suffered severe damage during the Wenchuan earthquake. Elastic analyses for 18 RC structure models with and without staircases are conducted and compared ...Many staircases in reinforced concrete (RC) frame structures suffered severe damage during the Wenchuan earthquake. Elastic analyses for 18 RC structure models with and without staircases are conducted and compared to study the influence of the staircase on the stiffness, displacements and internal forces of the structures. To capture the yielding development and damage mechanism of frame structures, elasto-plastic analysis is carried out for one of the 18 models. Based on the features observed in the analyses, a new type of staircase design i.e., isolating them from the master structure to eliminate the effect of K-type struts, is proposed and discussed. It is concluded that the proposed method of staircase isolation is effective and feasible for engineering design, and does not significantly increase the construction cost.展开更多
A sequence of periodic attractors has been observed in a two-dimensional discontinuous map, which canbe considered as a model of impact oscillator. The so-called 'transfer number', which is defined as the mean...A sequence of periodic attractors has been observed in a two-dimensional discontinuous map, which canbe considered as a model of impact oscillator. The so-called 'transfer number', which is defined as the mean numberof transfer from non-impact state to impact state per iteration, is locked onto a lot of rational values to form a curveconsisting of many steps. Our numerical investigation confirms that every step is confined by conditions created by thecollision between the periodic orbit and the discontinuous boundary of the system. After the last collision the systemshows a chaotic motion with intermittent characteristics. Therefore the staircase can be addressed as a 'prelude staircaseto type V intermittency'. The similar phenomenon has also been observed in a model of electric circuit. These resultsof our study suggest that this kind of staircases is common in two (or even higher) dimensional discontinuous maps.展开更多
Let g be the general linear Lie algebra consisting of all n x n matrices over a field F and with the usual bracket operation {x, y} =xy - yx. An invertible map φ : g →g is said to preserve staircase subalgebras if ...Let g be the general linear Lie algebra consisting of all n x n matrices over a field F and with the usual bracket operation {x, y} =xy - yx. An invertible map φ : g →g is said to preserve staircase subalgebras if it maps every staircase subalgebra to some staircase subalgebra of the same dimension. In this paper, we devote to giving an explicit description on the invertible maps on g that preserve staircase subalgebras.展开更多
A staircase provides the main escape way from a building in an emergency.Unfortunately,it may suffer severe damages or even collapse during an earthquake.For improving the seismic performance of staircases,this paper ...A staircase provides the main escape way from a building in an emergency.Unfortunately,it may suffer severe damages or even collapse during an earthquake.For improving the seismic performance of staircases,this paper proposes an innovative staircase isolator with the features of lightweight,costeffective and ease of construction and replacement,which is formed by suitable engineering plastic shims between rubber layers.A connection construction scheme is also proposed for the isolated staircase.Systematic performance tests have been carried out to characterize the isolator in terms of mechanic behavior and ultimate states.The test results show that mechanical properties of the proposed staircase isolator are excellent and suitable for staircase in building structure.In order to investigate the influence of staircase on building structural responses,time history analyses of a typical building structure without staircase(WS),with fixed staircase(FS)and with isolated staircase(IS)are conducted and compared within the environment of SAP2000.Results show that staircase isolation can effectively eliminate the diagonal bracing effect of staircase slab and make structural components uniformly stressed.When the novel isolator is employed for staircase in a building structure,there is no vulnerable position in staircase and the performance of staircase in building structure can be greatly enhanced.展开更多
Existing broadcasting schemes provide services for the stored videos. The basic approach in these schemes is to divide the video into segments and organize them over the channels for proper transmission. Some schemes ...Existing broadcasting schemes provide services for the stored videos. The basic approach in these schemes is to divide the video into segments and organize them over the channels for proper transmission. Some schemes use segments as a basic unit, whereas the others require segments to be further divided into subsegments. In a scheme, the number of segments/subsegments depends upon the bandwidth allocated to the video by the video server. For constructing segments, the video length should be known. If it is unknown, then the segments cannot be constructed and hence the scheme cannot be applied to provide the video services. This is an important issue especially in live broadcasting applications wherein the ending time of the video is unknown, for example, cricket match. In this paper, we propose a mechanism for the conservative staircase scheme so that it can support live video broadcasting.展开更多
We present the findings for the quantum conductance staircase of holes that is caused by the edge channels in the ultra-shallow p-type silicon quantum well (Si-QW), 2 nm, confined by the δ-barriers heavily doped with...We present the findings for the quantum conductance staircase of holes that is caused by the edge channels in the ultra-shallow p-type silicon quantum well (Si-QW), 2 nm, confined by the δ-barriers heavily doped with boron on the n-type Si (100) surface. This longitudinal quantum conductance staircase, Gxx, is revealed by the voltage applied to the Hall contacts, Vxy, to a maximum of 4e2/h. In addition to the standard plateau, 2e2/h, the variations of the Vxy voltage appear to exhibit the fractional forms of the quantum conductance staircase with the plateaus and steps that bring into correlation respectively with the odd and even fractional values.展开更多
Asymptotically necessary and sufficient quadratic stability conditions of Takagi-Sugeno (T-S) fuzzy systems are obtained by utilizing staircase membership functions and a basic inequality. The information of the membe...Asymptotically necessary and sufficient quadratic stability conditions of Takagi-Sugeno (T-S) fuzzy systems are obtained by utilizing staircase membership functions and a basic inequality. The information of the membership functions is incorporated in the stability analysis by approximating the original continuous membership functions with staircase membership functions. The stability of the T-S fuzzy systems was investigated based on a quadratic Lyapunov function. The asymptotically necessary and sufficient stability conditions in terms of linear matrix inequalities were derived using a basic inequality. A fuzzy controller was also designed based on the stability results. The derivation process of the stability results is straightforward and easy to understand. Case studies confirmed the validity of the obtained stability results.展开更多
We report the first nuclear magnetic resonance (NMR) study on single crystals of staircase Kagome antiferromagnet PbCu3Te07 (TN1 -36K). A Curie constant θ -140K is obtained by a Curie Weiss fit to the high- tempe...We report the first nuclear magnetic resonance (NMR) study on single crystals of staircase Kagome antiferromagnet PbCu3Te07 (TN1 -36K). A Curie constant θ -140K is obtained by a Curie Weiss fit to the high- temperature Knight shift of 125 Te. The hyperfine coupling constant is estimated to be 125Ahf = -67 kOe/#B, and a strong interlayer coupling among staircase Kagome planes is suggested with such a large hyperfine coupling, according to the lattice structure. The 63,65Cu NMR spectra are found by the zero-field (ZF) NMR at T = 2 K, and the internal hyperfine fields are estimated to be 10.3 T and 9.6 T, for Cu(1) and Cu(2) sites, respectively, in the lattice. A second type of ZF NMFt signal with a large rf enhancement is also seen after field-cycling through a high magnetic field.展开更多
可编程约瑟夫森电压基准(programmable Josephson voltage standard,PJVS)通过生成阶梯波构建交流量子电压,其产生量子电压台阶过程中,会伴生过渡过程,导致电压台阶两端数据的准确性较低。常见的数据处理方法是将过渡过程的数据剔除,仅...可编程约瑟夫森电压基准(programmable Josephson voltage standard,PJVS)通过生成阶梯波构建交流量子电压,其产生量子电压台阶过程中,会伴生过渡过程,导致电压台阶两端数据的准确性较低。常见的数据处理方法是将过渡过程的数据剔除,仅利用量子电压台阶上平稳区的数据,实现交流量子电压量值的复现。针对常用的3σ(σ为数据标准差)准则、片段采样方法等数据筛选准则,该文提出一种由量子电压台阶中心双向延拓并最小化A类测量不确定度的平稳区与过渡区判据,通过自动识别量子电压台阶的平稳区与过渡区,提升PJVS电压阶梯波复现交流电压量值的准确性。实验结果表明:该文提出的数据平稳区与过渡区的判据具有较高的鲁棒性和交流电压复现准确性,在2.5 kHz范围内,可使量子电压阶梯波信号复现交流电压幅值的偏差和A类测量不确定度均优于2.5×10-6。研究成果可有效提升量子电压阶梯波信号的测算准确性。展开更多
文摘A basic 7-level MLI topology is developed and the same is extended to the 9-level then further increased to 17-levels.The developed structure minimizes the component’s count and size to draw out the system economy.Despite the various advantages of MLIs,efficiency and reliability play a major role since the usage of components is higher for getting a low Total Harmonics Distortion(THD)value.This becomes a major challenge incorporated in boosting the efficiency without affecting the THD value.Various parametric observations are done and realized for the designed 9-level and 17-level MLI,being the Total Standing Voltage(TSV),efficiency,cost function per level count,and power loss.The respective parameters are compared with several existing and modern circuits and found to be effective in their performance.A novel single-phase 17-level asymmetrical Multi-Level Inverter(MLI)topology is developed to reduce the number of overall components.The developed topology generates 17-levels by using unequal DC sources.The developed MLI is proved under various tests con-ducted experimentally for the various loads like resistive,inductive,and combinational loads.A detailed comparison is done on several factors and represented graphically represented.Further,the proposed design provides a less TSV value is 6 V_(dc),efficiency is 94.21%and cost factor per level CF/L value for both values ofαis 2.01 and 2.05 and devices count with a low THD value 41.4%with respectively.
基金The National Key Technologies R&D Program under Grant No. 2009BAJ28B01The Technologies R&D Program of China State Construction Engineering Co., Ltd under Grant No. CSCEC-2009-Z-15
文摘Many staircases in reinforced concrete (RC) frame structures suffered severe damage during the Wenchuan earthquake. Elastic analyses for 18 RC structure models with and without staircases are conducted and compared to study the influence of the staircase on the stiffness, displacements and internal forces of the structures. To capture the yielding development and damage mechanism of frame structures, elasto-plastic analysis is carried out for one of the 18 models. Based on the features observed in the analyses, a new type of staircase design i.e., isolating them from the master structure to eliminate the effect of K-type struts, is proposed and discussed. It is concluded that the proposed method of staircase isolation is effective and feasible for engineering design, and does not significantly increase the construction cost.
文摘A sequence of periodic attractors has been observed in a two-dimensional discontinuous map, which canbe considered as a model of impact oscillator. The so-called 'transfer number', which is defined as the mean numberof transfer from non-impact state to impact state per iteration, is locked onto a lot of rational values to form a curveconsisting of many steps. Our numerical investigation confirms that every step is confined by conditions created by thecollision between the periodic orbit and the discontinuous boundary of the system. After the last collision the systemshows a chaotic motion with intermittent characteristics. Therefore the staircase can be addressed as a 'prelude staircaseto type V intermittency'. The similar phenomenon has also been observed in a model of electric circuit. These resultsof our study suggest that this kind of staircases is common in two (or even higher) dimensional discontinuous maps.
基金The NSF (11126121) of ChinaPh.D.Fund (B2010-93) of Henan Polytechnic University+1 种基金Natural Science Research Program (112300410120) of Science and Technology Department of Henan ProvinceNatural Science Research Program (2011B110016) of Education Department of Henan Province
文摘Let g be the general linear Lie algebra consisting of all n x n matrices over a field F and with the usual bracket operation {x, y} =xy - yx. An invertible map φ : g →g is said to preserve staircase subalgebras if it maps every staircase subalgebra to some staircase subalgebra of the same dimension. In this paper, we devote to giving an explicit description on the invertible maps on g that preserve staircase subalgebras.
基金This work was supported by the National Key Research and Development Program of China(Grant No.2017YFC0703600)the National Natural Science Foundation of China(Grant Nos.51278138,51978185)+1 种基金Yangcheng Scholar’s Program of Guangzhou Municipal Department of Education(Grant No.1201541630)Innovation Research Program for the Postgraduates of Guangzhou University(Grant No.2017GDJC-D16).
文摘A staircase provides the main escape way from a building in an emergency.Unfortunately,it may suffer severe damages or even collapse during an earthquake.For improving the seismic performance of staircases,this paper proposes an innovative staircase isolator with the features of lightweight,costeffective and ease of construction and replacement,which is formed by suitable engineering plastic shims between rubber layers.A connection construction scheme is also proposed for the isolated staircase.Systematic performance tests have been carried out to characterize the isolator in terms of mechanic behavior and ultimate states.The test results show that mechanical properties of the proposed staircase isolator are excellent and suitable for staircase in building structure.In order to investigate the influence of staircase on building structural responses,time history analyses of a typical building structure without staircase(WS),with fixed staircase(FS)and with isolated staircase(IS)are conducted and compared within the environment of SAP2000.Results show that staircase isolation can effectively eliminate the diagonal bracing effect of staircase slab and make structural components uniformly stressed.When the novel isolator is employed for staircase in a building structure,there is no vulnerable position in staircase and the performance of staircase in building structure can be greatly enhanced.
文摘Existing broadcasting schemes provide services for the stored videos. The basic approach in these schemes is to divide the video into segments and organize them over the channels for proper transmission. Some schemes use segments as a basic unit, whereas the others require segments to be further divided into subsegments. In a scheme, the number of segments/subsegments depends upon the bandwidth allocated to the video by the video server. For constructing segments, the video length should be known. If it is unknown, then the segments cannot be constructed and hence the scheme cannot be applied to provide the video services. This is an important issue especially in live broadcasting applications wherein the ending time of the video is unknown, for example, cricket match. In this paper, we propose a mechanism for the conservative staircase scheme so that it can support live video broadcasting.
文摘We present the findings for the quantum conductance staircase of holes that is caused by the edge channels in the ultra-shallow p-type silicon quantum well (Si-QW), 2 nm, confined by the δ-barriers heavily doped with boron on the n-type Si (100) surface. This longitudinal quantum conductance staircase, Gxx, is revealed by the voltage applied to the Hall contacts, Vxy, to a maximum of 4e2/h. In addition to the standard plateau, 2e2/h, the variations of the Vxy voltage appear to exhibit the fractional forms of the quantum conductance staircase with the plateaus and steps that bring into correlation respectively with the odd and even fractional values.
文摘Asymptotically necessary and sufficient quadratic stability conditions of Takagi-Sugeno (T-S) fuzzy systems are obtained by utilizing staircase membership functions and a basic inequality. The information of the membership functions is incorporated in the stability analysis by approximating the original continuous membership functions with staircase membership functions. The stability of the T-S fuzzy systems was investigated based on a quadratic Lyapunov function. The asymptotically necessary and sufficient stability conditions in terms of linear matrix inequalities were derived using a basic inequality. A fuzzy controller was also designed based on the stability results. The derivation process of the stability results is straightforward and easy to understand. Case studies confirmed the validity of the obtained stability results.
基金Supported by the National Natural Science Foundation of China under Grant Nos 11374364 and 11222433the National Basic Research Program of China under Grant No 2011CBA00112the Scientific Research Foundation for the Returned Overseas Chinese Scholars of State Education Ministry
文摘We report the first nuclear magnetic resonance (NMR) study on single crystals of staircase Kagome antiferromagnet PbCu3Te07 (TN1 -36K). A Curie constant θ -140K is obtained by a Curie Weiss fit to the high- temperature Knight shift of 125 Te. The hyperfine coupling constant is estimated to be 125Ahf = -67 kOe/#B, and a strong interlayer coupling among staircase Kagome planes is suggested with such a large hyperfine coupling, according to the lattice structure. The 63,65Cu NMR spectra are found by the zero-field (ZF) NMR at T = 2 K, and the internal hyperfine fields are estimated to be 10.3 T and 9.6 T, for Cu(1) and Cu(2) sites, respectively, in the lattice. A second type of ZF NMFt signal with a large rf enhancement is also seen after field-cycling through a high magnetic field.
文摘可编程约瑟夫森电压基准(programmable Josephson voltage standard,PJVS)通过生成阶梯波构建交流量子电压,其产生量子电压台阶过程中,会伴生过渡过程,导致电压台阶两端数据的准确性较低。常见的数据处理方法是将过渡过程的数据剔除,仅利用量子电压台阶上平稳区的数据,实现交流量子电压量值的复现。针对常用的3σ(σ为数据标准差)准则、片段采样方法等数据筛选准则,该文提出一种由量子电压台阶中心双向延拓并最小化A类测量不确定度的平稳区与过渡区判据,通过自动识别量子电压台阶的平稳区与过渡区,提升PJVS电压阶梯波复现交流电压量值的准确性。实验结果表明:该文提出的数据平稳区与过渡区的判据具有较高的鲁棒性和交流电压复现准确性,在2.5 kHz范围内,可使量子电压阶梯波信号复现交流电压幅值的偏差和A类测量不确定度均优于2.5×10-6。研究成果可有效提升量子电压阶梯波信号的测算准确性。