共查询到20条相似文献,搜索用时 31 毫秒
1.
Yongjun Tian Tiansheng Wang Ke Chen Lie Chen Dongning Zheng Hanhong Qi Sven Linzen Frank Schmidl Paul Seidel 《中国科学 数学(英文版)》2000,43(1):82-87
A flip-chip-type gradiometer has been constructed with a 10 mm × 5 mm planar DCSQUID gradiometer fabricated on a SrTiO3 bicrystal substrate and a flux transformer made from a YBCO*/YBCO/CeO2/YSZ multilayer on ?50.8 mm Si wafer. The coupling coefficient between the flux transformer and the planar gradiometer is 0.18. The transformer increases effectively the resolution of the gradiometer. A magnetic field gradient resolution of 73 fT.cm?1Hz?1/2 in the white region and 596 fT.cm?1Hz?1/2 at 1 Hz has been obtained. High quality magnetocardiogram signals have been successfully measured by using this flip-chip-type gradiometer in an unshielded environment. 相似文献
2.
Yongjun Tian Tiansheng Wang Ke Chen Lie Chen Dongning Zheng Hanhong Qi Sven Linzen Frank Schmidl Paul Seidel 《中国科学A辑(英文版)》2000,43(1):82-87
A flip-chip-type gradiometer has been constructed with a 10 mm × 5 mm planar DCSQUID gradiometer fabricated on a SrTiO3 bicrystal substrate and a flux transformer made from a YBCO*/YBCO/CeO2/YSZ multilayer on ϕ50.8 mm Si wafer. The coupling coefficient between the flux transformer and the planar gradiometer is
0.18. The transformer increases effectively the resolution of the gradiometer. A magnetic field gradient resolution of 73
fT.cm−1Hz−1/2 in the white region and 596 fT.cm−1Hz−1/2 at 1 Hz has been obtained. High quality magnetocardiogram signals have been successfully measured by using this flip-chip-type
gradiometer in an unshielded environment. 相似文献
3.
Biaobing Jin Lin Kang Ruixin Wu Jianyu Zhang Qiheng Cheng Peiheng Wu Dong Jing Gang Jiao Kai Shao Mingming Jiang Jiazong Zhang Minsong Sun Yunyi Wang Yueliang Zhou Huibin Lü Shifa Xu Meng He Xiaoping Wang Bingchuan Yang Jian Lu Qishao Zhang 《中国科学A辑(英文版)》1997,40(2):219-224
A high-T
c superconducting (HTSC) thin film/GaAs MESFET hybrid microwave oscillator operated at 10.6 GHz has been designed, fabricated
and characterized. Microstrip line structures were used throughout the circuit with superconducting thin film YBa2Cu3O7-δ(YBCO) as the conductor material. The YBCO thin films were deposited on 15 mm×10 mm×0.5 mm LaAlO3 substrates. The oscillator was common-source, series feedback type using a GaAs-MESFET (NE72084) as the active device and
a superconducting microstrip resonator as the frequency stabilizing element. By improving the unloaded quality factorQ
0 of the superconducting microstrip resonator and adjusting the coupling coefficient between the resonator and the gate of
the MESFET, the phase noise of the oscillator was decreased. At 77 K, the phase noise of the oscillator at 10 kHz offset from
carrier was −87 dBc/Hz.
Project supported by the National Center for Research and Development on Superconductivity of China. 相似文献
4.
5.
关于Aluthge变换的数值域 总被引:3,自引:0,他引:3
设A是作用在希耳伯特空间H上的有界线性算子,如果A=V A是算子A的极分解,则定义A~=A 12V A 21和A~(*)=A*21V A*21分别为算子A的Aluthge变换A~和*-Aluthge变换A~(*).记A~和A~(*)的数值域分别为W(A~)和W(A~(*)).证明了W(A~)=W(A~(*)),即肯定了吴提出的一个猜想. 相似文献
6.
本文研究了连续时间下非参数回归的误差官度估计的收敛速度,给出了一定条件下误差密度的估计量^fT(x)的均方收敛速度,详细说明了以下重要结果:E[^fT(x)-f(x)]^2=O(T^-1/4)其中f(x)表示误差过程{et,t≥0}的未知密度。 相似文献
7.
Ion beam assisted pulsed laser deposition of biaxially aligned yttria-stabilized zirconia (YSZ) was used to produce a buffer
layer for YBCO film on polycrystalline metallic substrate. The YSZ layers were biaxially aligned with (001) axis normal to
the substrate. The minimum FWHM of (111) phi-scan of the YSZ was 19°, and the minimum FWHM of the rocking curve of YSZ was
4.5°. Highly c-axis oriented biaxially aligned YBCO thin films were epitaxially grown by laser ablation on these layers, with
JC(77K, 0T) = 2.1 × 105 A/cm2,
.
Project supported by the National Center for R&D on Superconductivity of China. 相似文献
8.
《数学季刊》2016,(2):111-117
Let D(G) = (dij )n×n denote the distance matrix of a connected graph G with order n, where dij is equal to the distance between vertices vi and vj in G. A graph is called distance integral if all eigenvalues of its distance matrix are integers. In 2014, Yang and Wang gave a su?cient and necessary condition for complete r-partite graphs Kp1,p2,··· ,pr =Ka1·p1,a2·p2,··· ,as···ps to be distance integral and obtained such distance integral graphs with s = 1, 2, 3, 4. However distance integral complete multipartite graphs Ka1·p1,a2·p2,··· ,as·ps with s>4 have not been found. In this paper, we find and construct some infinite classes of these distance integral graphs Ka1·p1,a2·p2,··· ,as·ps with s = 5, 6. The problem of the existence of such distance integral graphs Ka1·p1,a2·p2,··· ,as·ps with arbitrarily large number s remains open. 相似文献
9.
10.
CHEN Fan LB Huibin ZHAO Tong WANG Rongping ZHOU Yueliang CHEN Zhenghao YANG Guozhen 《中国科学A辑(英文版)》2001,44(7):947-952
High quality YBa2.Cu3O6 +x(YBCO) superconductive thin films have been fabricated on the SrTiO3(100) substrate using laser molecular beam epitaxy (laser-MBE). The active oxygen source was used, which made the necessary
ambient oxygen pressure be 2–3 orders lower than that in pulsed laser deposition (PLD). Tc0 is 85–87 K, and Jc, 1.0 × 106 A/cm2. Atomic force microscopy (AFM) measurements show that no obvious particulates can be observed and the root mean square roughness
is 7.8 nm. High stability DC superconducting quantum interference devices (DC-SQUID) was fabricated using this YBCO thin film. 相似文献
11.
Karen Seyffarth 《Journal of Graph Theory》1989,13(5):619-648
A maximal planar graph is a simple planar graph in which every face is a triangle. We show here that such graphs with maximum degree Δ and diameter two have no more than 3/2Δ + 1 vertices. We also show that there exist maximal planar graphs with diameter two and exactly [3/2Δ + 1] vertices. 相似文献
12.
《Journal of Graph Theory》2018,88(1):101-109
A graph is 1‐planar if it can be drawn in the plane such that each edge is crossed at most once. A graph, together with a 1‐planar drawing is called 1‐plane. A graph is maximal 1‐planar (1‐plane), if we cannot add any missing edge so that the resulting graph is still 1‐planar (1‐plane). Brandenburg et al. showed that there are maximal 1‐planar graphs with only edges and maximal 1‐plane graphs with only edges. On the other hand, they showed that a maximal 1‐planar graph has at least edges, and a maximal 1‐plane graph has at least edges. We improve both lower bounds to . 相似文献
13.
14.
15.
It has been known that every planar 4-graph has a 2-bend 2-D orthogonal drawing, with the only exception being the octahedron, every planar 3-graph has a 1-bend 2-D orthogonal drawing with the only exception being K4, and every outerplanar 3-graph with no triangles has a 0-bend 2-D orthogonal drawing. We show in this paper that every series-parallel 4-graph has a 1-bend 2-D orthogonal drawing. 相似文献
16.
《数学季刊》2016,(4):369-378
In this paper, we investigate the growth of solutions of the differential equations f(k)+Ak?1(z)f(k?1)+· · ·+A0(z)f =0, where Aj(z)(j=0, · · · , k?1) are entire functions. When there exists some coe?cient As(z)(s ∈ {1, · · · , k?1}) being a nonzero solution of f00+P(z)f =0, where P(z) is a polynomial with degree n(≥1) and A0(z) satisfiesσ(A0)≤1/2 or its Taylor expansion is Fabry gap, we obtain that every nonzero solution of such equations is of infinite order. 相似文献
17.
本文证明若A =(A1 ,A2 ,… )和B =(B1 ,B2 ,… )是Hilber空间H上的交换的正常算子列 ,满足条件 ∑∞j=1A j Aj=I和 ∑∞j=1B jBj =I.则对H上任何有界线性算子X ,由 ∑∞j=1AjXBj =X 可推得 :等式AjX =XBj和A jX =XB j 对所有的j成立 相似文献
18.
The resolution and the robustness of the weighted essentially non-oscillatory (WENO) scheme and two-step finite-difference WENO (TSFDWENO) schemes
are compared by strictly using the same flux evaluation method and smoothness indicators. TSFDWENO schemes are defined to include a family of weighted compact
nonlinear scheme (WCNS) and an alternative WENO scheme. Comparison results indicate that WCNS has a higher resolution than the WENO scheme, while the WENO
scheme is more robust than WCNS. Additionally, various flux evaluation methods
are combined with TSFDWENO schemes, and they are evaluated. Then, the effects
of the flux evaluation methods on the resolution and robustness of the scheme are
investigated, and the results show that the robustness and the resolution can be significantly altered by changing the flux evaluation method. This study reveals the
advantage of being able to use various flux evaluation methods in the TSFDWENO
scheme as well as the fair comparison of the WENO schemes and WCNS. On the
other hand, these effects are marginalized when changing the interpolation and differencing method. Such knowledge can be important when selecting schemes for
actual simulation and developing guidelines for scheme improvement. 相似文献
19.
Michael D. Plummer 《Discrete Mathematics》1996,150(1-3):315-324
A graph G on at least 2n + 2 vertices in n-extendable if every set of n independent edges extends to (i.e., is a subset of) a perfect matching in G. It is known that no planar graph is 3-extendable. In the present paper we continue to study 2-extendability in the plane. Suppose independent edges e1 and e2 are such that the removal of their endvertices leaves at least one odd component Co. The subgraph G[V(Co) V(e1) V(e2)] is called a generalized butterfly (or gbutterfly). Clearly, a 2-extendable graph can contain no gbutterfly. The converse, however, is false.
We improve upon a previous result by proving that if G is 4-connected, locally connected and planar with an even number of vertices and has no gbutterfly, it is 2-extendable. Sharpness with respect to the various hypotheses of this result is discussed. 相似文献
20.
完全多部图的无符号Laplacian特征多项式(英文) 总被引:1,自引:0,他引:1
For a simple graph G,let matrix Q(G)=D(G) + A(G) be it’s signless Laplacian matrix and Q G (λ)=det(λI Q) it’s signless Laplacian characteristic polynomial,where D(G) denotes the diagonal matrix of vertex degrees of G,A(G) denotes its adjacency matrix of G.If all eigenvalues of Q G (λ) are integral,then the graph G is called Q-integral.In this paper,we obtain that the signless Laplacian characteristic polynomials of the complete multi-partite graphs G=K(n1,n2,···,nt).We prove that the complete t-partite graphs K(n,n,···,n)t are Q-integral and give a necessary and sufficient condition for the complete multipartite graphs K(m,···,m)s(n,···,n)t to be Q-integral.We also obtain that the signless Laplacian characteristic polynomials of the complete multipartite graphs K(m,···,m,)s1(n,···,n,)s2(l,···,l)s3. 相似文献