Deploying Picocell Base Station(PBS) throughout a Macrocell is a promising solution for capacity improvement in the next generation wireless networks.However,the strong received power from Macrocell Base Station(MBS) ...Deploying Picocell Base Station(PBS) throughout a Macrocell is a promising solution for capacity improvement in the next generation wireless networks.However,the strong received power from Macrocell Base Station(MBS) makes the areas of Picocell narrow and limits the gain of cell splitting.In this paper,we firstly propose a Dynamic Cell Range Expansion(DCRE) strategy.By expanding the coverage of the cell,we aim to balance the network load between MBS and PBS.Then,we present a cooperative Resource block and Power Allocation Scheme(coRPAS)based on DCRE.The objective of coRPAS is to decrease interference caused by MBS and Macrocell User Equipments,by which we can expand regions of Picocell User Equipments.Simulation results demonstrate the superiority of our method through comparing with other existing methods.展开更多
The effect of diffraction on the ultrasonic velocity measured by the pulse interference method has been investigated in VHF range theoretically and experimentally. Two silicate glasses are taken as the specimens, thei...The effect of diffraction on the ultrasonic velocity measured by the pulse interference method has been investigated in VHF range theoretically and experimentally. Two silicate glasses are taken as the specimens, their frequency dependences of longitudinal velocities are measured in the frequency range of 50-350 MHz, and the phase advances of ultrasonic signals caused by diffraction effect are calculated using A. O. Williams' theoretical expression. For the velocity error due to diffraction effect, the experimental results are in good agreement with the theoretical prediction. It has been shown that the velocity error due to diffraction effect is directly proportional to dθ21 (f)/df, whereθ21 (f) is the phase advances difference between the two partial reflection signals used in velocity measurement and f is the ultrasonic frequency.展开更多
Multicellular organisms, like higher plants, need to coordinate their growth and development and to cope with environmental cues. To achieve this, various signal molecules are transported between neighboring cells and...Multicellular organisms, like higher plants, need to coordinate their growth and development and to cope with environmental cues. To achieve this, various signal molecules are transported between neighboring cells and distant organs to control the fate of the recipient cells and organs. RNA silencing produces cell non-autonomous signal molecules that can move over short or long distances leading to the sequence specific silencing of a target gene in a well defined area of cells or throughout the entire plant,respectively. The nature of these signal molecules, the route of silencing spread, and the genes involved in their production, movement and reception are discussed in this review. Additionally, a short section on features of silencing spread in animal models is presented at the end of this review.展开更多
基金supported in part by the National Natural Science Foundation of China（61172051,61302070,61202071, 61302072） the Fundamental Research Funds for the Central Universities （N110804003,N120804002,N120404001, N120604001）+1 种基金 the Program for New Century Excellent Talents in University（NCET-120102） the Specialized Research Fund for the Doctoral Program of Higher Education （20120042120049）
文摘Deploying Picocell Base Station(PBS) throughout a Macrocell is a promising solution for capacity improvement in the next generation wireless networks.However,the strong received power from Macrocell Base Station(MBS) makes the areas of Picocell narrow and limits the gain of cell splitting.In this paper,we firstly propose a Dynamic Cell Range Expansion(DCRE) strategy.By expanding the coverage of the cell,we aim to balance the network load between MBS and PBS.Then,we present a cooperative Resource block and Power Allocation Scheme(coRPAS)based on DCRE.The objective of coRPAS is to decrease interference caused by MBS and Macrocell User Equipments,by which we can expand regions of Picocell User Equipments.Simulation results demonstrate the superiority of our method through comparing with other existing methods.
文摘The effect of diffraction on the ultrasonic velocity measured by the pulse interference method has been investigated in VHF range theoretically and experimentally. Two silicate glasses are taken as the specimens, their frequency dependences of longitudinal velocities are measured in the frequency range of 50-350 MHz, and the phase advances of ultrasonic signals caused by diffraction effect are calculated using A. O. Williams' theoretical expression. For the velocity error due to diffraction effect, the experimental results are in good agreement with the theoretical prediction. It has been shown that the velocity error due to diffraction effect is directly proportional to dθ21 (f)/df, whereθ21 (f) is the phase advances difference between the two partial reflection signals used in velocity measurement and f is the ultrasonic frequency.
基金co-financed by the European Union(European Social Fund–ESF)Greek national funds through the Operational Program"Education and Lifelong Learning"of the National Strategic Reference Framework(NSRF)–Research Funding Program:Heracleitus Ⅱ+1 种基金the European Social Fund(G.M.)Postdoctoral Grant LS1-1190(F.V)
文摘Multicellular organisms, like higher plants, need to coordinate their growth and development and to cope with environmental cues. To achieve this, various signal molecules are transported between neighboring cells and distant organs to control the fate of the recipient cells and organs. RNA silencing produces cell non-autonomous signal molecules that can move over short or long distances leading to the sequence specific silencing of a target gene in a well defined area of cells or throughout the entire plant,respectively. The nature of these signal molecules, the route of silencing spread, and the genes involved in their production, movement and reception are discussed in this review. Additionally, a short section on features of silencing spread in animal models is presented at the end of this review.
