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排序方式: 共有10000条查询结果,搜索用时 343 毫秒
941.
Guoxi Xie Songlin Feng Xiangqian Feng Jihao Zhu Yongqiang Li 《Nuclear instruments & methods in physics research. Section B, Beam interactions with materials and atoms》2007,264(1):103-108
Imitated GE ware was one of the most famous products of Jingdezhen porcelain field in Ming dynasty (AD 1368-1644). The exterior features of its body and glaze are very marvelous. Black foot, purple mouth and crazing glaze are the main features of imitated GE ware. Until now, the key conditions of resulting these features are not clearly identified. In order to find the critical elements for firing these features, instrumental neutron activation analysis (INAA) and wavelength-dispersive X-ray fluorescence (WDXRF) were used to determine the element abundance patterns of imitated GE ware body and glaze. The experimental data was compared with that of imitated Longquan celadon and of Longquan celadon. The analytical results indicated that Fe, Ti and Na were the critical elements. The body of imitated GE ware which contains high Fe and Ti are the basic conditions of firing its black body, black foot and purple mouth. The glaze of imitated GE ware which contains high Na is the main condition of producing its crazing glaze. Na is the critical element which enlarges the difference in expansion coefficients between the glaze and body of imitated GE ware. Furthermore, Zijin soil was added into kaolin to make the body rich in Fe and Ti. And something which was rich in Na was used to produce crazing glaze in the manufacturing process of imitated GE ware. 相似文献
942.
Drawing Power Law Graphs Using a Local/Global Decomposition 总被引:1,自引:0,他引:1
943.
Jeffrey E. Marchese Matteo Cirillo Niels Grøch-Jensen 《Open Systems & Information Dynamics》2007,14(2):189-196
We present evidence for a close analogy between the nonlinear behaviour of a pulsed microwave-driven Josephson junction at
low temperature and the experimentally observed behaviour of Josephson systems operated below the quantum transition temperature
under similar conditions. We specifically address observations of Ramsey-type fringe oscillations, which can be understood
in classical nonlinear dynamics as results of slow transient oscillations in a pulsed microwave environment. Simulations are
conducted to mimic experimental measurements by recording the statistics of microwave-induced escape events from the anharmonic
potential well of a zero-voltage state. Observations consistent with experimentally obtained Ramsey-type oscillations are
found in the classical model.
An erratum to this article can be found at 相似文献
944.
Hanna Podsȩdkowska 《Open Systems & Information Dynamics》2007,14(4):445-458
The paper investigates correlations in a general theory of quantum measurement based on the notion of instrument. The analysis
is performed in the algebraic formalism of quantum theory in which the observables of a physical system are described by a
von Neumann algebra, and the states—by normal positive normalized functionals on this algebra. The results extend and generalise
those obtained for the classical case where one deals with the full algebra of operators on a Hilbert space. 相似文献
945.
Yvan Van Rentergem Alexis De Vos Koen De Keyser 《Open Systems & Information Dynamics》2007,14(1):91-116
The (2
w
)! reversible transformations on w wires, i.e. reversible logic circuits with w inputs and w outputs, together with the action of cascading, form a group, isomorphic to the symmetric group S
2
w
. Therefore, we investigate the group S
n
as well as one of its subgroups isomorphic to S
n/2 × S
n/2. We then consider the left cosets, the right cosets, and the double cosets generated by the subgroup. Each element of a coset
can function as the representative of the coset. The coset can then be considered as the set of all group elements that differ
from the representative by merely multiplying (either to the left or to the right or to both sides) by an arbitrary element
of the subgroup. Different choices of the coset space and different choices of the coset representatives lead to six different
syntheses for implementing an arbitrary reversible logic operation into hardware. Evaluation of all six methods, by means
of three different cost functions (gate cost, switch cost, and quantum cost), leads to a best choice. 相似文献
946.
Jose R. Rios Viqueira Nikos A. Lorentzos 《The VLDB Journal The International Journal on Very Large Data Bases》2007,16(2):179-200
An SQL extension is formalized for the management of spatio-temporal data, i.e. of spatial data that evolves with respect
to time. The extension is dedicated to applications such as topography, cartography, and cadastral systems, hence it considers
discrete changes both in space and in time. It is based on the rigid formalization of data types and of SQL constructs. Data types are defined in terms of time and
spatial quanta. The SQL constructs are defined in terms of a kernel of few relational algebra operations, composed of the well-known operations of the 1NF model and of two more, Unfold and Fold. In conjunction with previous work, it enables the uniform management of 1NF structures that may contain not only spatio-temporal
but also either purely temporal or purely spatial or conventional data. The syntax and semantics of the extension is fully
consistent with the {SQL:2003} standard. 相似文献
947.
A necessary and sufficient condition is given for a connected bipartite graph to be the incidence graph of a contact family
of segments and points. We deduce that any four-connected three-colorable plane graph is the contact graph of a family of
segments and that any four-colored planar graph without an induced C4 using four colors is the intersection graph of a family of straight line segments. 相似文献
948.
Fast Recognition of Fibonacci Cubes 总被引:1,自引:0,他引:1
Fibonacci cubes are induced subgraphs of hypercubes based on Fibonacci strings. They were introduced to represent interconnection
networks as an alternative to the hypercube networks. We derive a characterization of Fibonacci cubes founded on the concept
of resonance graphs. The characterization is the basis for an algorithm which recognizes these graphs in O(mlog n) time.
A. Vesel supported by the Ministry of Science of Slovenia under the grant 0101-P-297. 相似文献
949.
通过对活性炭载体进行不同条件的超声波处理获得了具有不同表面化学性质的载体,使用比表面积(BET)、酸碱滴定等技术手段对载体的物理化学性质进行了表征。将经过超声波处理的活性炭载体制备成Pt/C催化剂,并将催化剂直接用于催化反应,考察了活性炭载体的不同超声波处理条件对Pt/C催化剂性能的影响。实验发现,活性炭载体经过超声波处理后,表面灰分含量、pH值和中孔孔容有较大的变化;使用经过60min超声波处理后中孔孔容较大的活性炭作为载体制备的Pt/C催化剂,在催化加氢反应性能测试中显示了最高的催化活性。在此基础上,就活性炭载体的超声波处理对Pt/C催化剂活性的影响进行了讨论。 相似文献
950.
Marco Lucamarini Alessandro Ceré Giovanni Di Giuseppe Stefano Mancini David Vitali Paolo Tombesi 《Open Systems & Information Dynamics》2007,14(2):169-178
The security of a deterministic quantum scheme for communication, namely the LM05 [1], is studied in presence of a lossy channel
under the assumption of imperfect generation and detection of single photons. It is shown that the scheme allows for a rate
of distillable secure bits higher than that pertaining to BB84 [2]. We report on a first implementation of LM05 with weak
pulses. 相似文献