It is proved that the set of all symmetric real matrices of order n with eigenvalues lying in the interval(α, β), denoted by Sn(α,β), is convex in Rn×n. With this result, some known results on positive(negati...It is proved that the set of all symmetric real matrices of order n with eigenvalues lying in the interval(α, β), denoted by Sn(α,β), is convex in Rn×n. With this result, some known results on positive(negative) definiteness, and Hurwitz(Shur) stability, as well as the aperiodic property of polytopes of symmetric matrices are generalized, and a series of insightful necessary and sufficient conditions for some general set of symmetric matrices contained in Sn(α,β) are presented,which are directly available for analysis of the positive(negative) definiteness, Hurwitz(Shur) stability and the aperiodic property of a wide class of sets of symmetric matrices.展开更多
基于Dyakonov-Shur效应（D-S效应）利用MOSFET可构建太赫兹源。研究表明MOSFET沟道内的1 m V信号在偏置电压的作用下产生波动并形成等离子波,其电学特性与谐振腔相似。当MOSFET外接5 V的偏置电压源时,输出频率为2.15 THz、峰值为2 m V...基于Dyakonov-Shur效应（D-S效应）利用MOSFET可构建太赫兹源。研究表明MOSFET沟道内的1 m V信号在偏置电压的作用下产生波动并形成等离子波,其电学特性与谐振腔相似。当MOSFET外接5 V的偏置电压源时,输出频率为2.15 THz、峰值为2 m V的等离子信号。通过调节偏置电压（1-20 V）可以使输出信号在0.96-4.30 THz范围内调频。此外,MOSFET在5 V的偏置电压和5 A的偏置电流的共同作用下,沟道内产生的等离子波随时间的推移以指数形式放大。受器件限制和沟道夹断效应影响,该信号源的最大输出电压为20 V,电压增益最大可达到86 d B,最大输出功率为200 W。在器件允许范围内,偏置电压越大信号频率越高、偏置电流越大起振时间越短,且偏置电流引起的信号频偏小。展开更多
In this paper, We give the simple criteria of weakly compact sets in L1 and l1, which perfects Auto's result [1]， Also as a corollary, we get Shur's theorem， In view of weak compactness, we give another pro...In this paper, We give the simple criteria of weakly compact sets in L1 and l1, which perfects Auto's result [1]， Also as a corollary, we get Shur's theorem， In view of weak compactness, we give another proof of the reflexivity of Orlicz spaces，展开更多
文摘It is proved that the set of all symmetric real matrices of order n with eigenvalues lying in the interval(α, β), denoted by Sn(α,β), is convex in Rn×n. With this result, some known results on positive(negative) definiteness, and Hurwitz(Shur) stability, as well as the aperiodic property of polytopes of symmetric matrices are generalized, and a series of insightful necessary and sufficient conditions for some general set of symmetric matrices contained in Sn(α,β) are presented,which are directly available for analysis of the positive(negative) definiteness, Hurwitz(Shur) stability and the aperiodic property of a wide class of sets of symmetric matrices.
文摘基于Dyakonov-Shur效应（D-S效应）利用MOSFET可构建太赫兹源。研究表明MOSFET沟道内的1 m V信号在偏置电压的作用下产生波动并形成等离子波,其电学特性与谐振腔相似。当MOSFET外接5 V的偏置电压源时,输出频率为2.15 THz、峰值为2 m V的等离子信号。通过调节偏置电压（1-20 V）可以使输出信号在0.96-4.30 THz范围内调频。此外,MOSFET在5 V的偏置电压和5 A的偏置电流的共同作用下,沟道内产生的等离子波随时间的推移以指数形式放大。受器件限制和沟道夹断效应影响,该信号源的最大输出电压为20 V,电压增益最大可达到86 d B,最大输出功率为200 W。在器件允许范围内,偏置电压越大信号频率越高、偏置电流越大起振时间越短,且偏置电流引起的信号频偏小。
文摘In this paper, We give the simple criteria of weakly compact sets in L1 and l1, which perfects Auto's result [1]， Also as a corollary, we get Shur's theorem， In view of weak compactness, we give another proof of the reflexivity of Orlicz spaces，
