Autor: Wu, S. - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Classification of self-dual torsion-free LCA groups
Autorzy:: Wu, S.
Wydawca:: Polska Akademia Nauk. Instytut Matematyczny PAN
Powiązania:: https://bibliotekanauki.pl/articles/1215033.pdf Link otwiera się w nowym oknie
Opis:: In this paper we seek to describe the structure of self-dual torsion-free LCA groups. We first present a proof of the structure theorem of self-dual torsion-free metric LCA groups. Then we generalize the structure theorem to a larger class of self-dual torsion-free LCA groups. We also give a characterization of torsion-free divisible LCA groups. Consequently, a complete classification of self-dual divisible LCA groups is obtained; and any self-dual torsion-free LCA group can be regarded as an open subgroup of a well-understood torsion-free divisible LCA group.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Theoretical Studies of the Spin Hamiltonian Parameters and Local Structures for the Two Tetragonal $Cu^{2+}$ Centers in $Ca(OH)_2$
Autorzy:: Zhang, H.
Wu, S.
Zhang, Z.
Tematy:: 76.30.Fc; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1493658.pdf Link otwiera się w nowym oknie
Opis:: The spin Hamiltonian parameters (g factors $g_{∥ },$ $g_{⊥}$ and the hyperfine structure constants $A_{∥ },$ $A_{⊥}$) and the local structures for the two tetragonal $Cu^{2+}$ centers I and II in $Ca(OH)_2$ are theoretically studied from the perturbation formulae of these parameters for a $3d^9$ ion under tetragonally elongated octahedra. The $[Cu(OH)_6]^{4-}$ clusters on the substitutional $Ca^{2+}$ site are found to suffer the relative elongations by about 0.083 Å and 0.065 Å for centers I and II, respectively, along the $C_4$ axis due to the Jahn-Teller effect. The above tetragonal elongations may entirely depress the original trigonal distortion of the host $Ca^{2+}$ site in $Ca(OH)_2$. The calculated spin Hamiltonian parameters based on the above Jahn-Teller elongations show good agreement with the experimental results. The EPR spectra and the local structures for the two centers are compared with one another.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Design of the state predictive model following control system with time-delay
Autorzy:: Wang, D.
Wu, S.
Okubo, S.
Tematy:: sterowanie predykcyjne
opóźnienie
kontrola przeciążeń
state predictive control
time delay
model following control system (MFCS)
TCP/AQM network
congestion control; Pokaż więcej
Wydawca:: Uniwersytet Zielonogórski. Oficyna Wydawnicza
Powiązania:: https://bibliotekanauki.pl/articles/907660.pdf Link otwiera się w nowym oknie
Opis:: Time-delay systems exist in many engineering fields such as transportation systems, communication systems, process engineering and, more recently, networked control systems. It usually results in unsatisfactory performance and is frequently a source of instability, so the control of time-delay systems is practically important. In this paper, a design of the state predictive model following control system (PMFCS) with time-delay is discussed. The bounded property of the internal states for the control is given, and the utility of this control design is guaranteed. Finally, examples are given to illustrate the effectiveness of the proposed method, and state predictive control techniques are applied to congestion control synthesis problems for a TCP/AQM network.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Generalized integrated importance measure for system performance evaluation: application to a propeller plane system
Uogólniona miara zintegrowanej ważności komponentów jako narzędzie oceny wydajności systemu: zastosowanie w odniesieniu do układu śmigłowca
Autorzy:: Dui, H.
Chen, L.
Wu, S.
Tematy:: wydajność systemu
miara ważności
rozkład Weibulla
szybkość przejścia
system performance
importance measure
Weibull distribution
transition rate; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Polskie Naukowo-Techniczne Towarzystwo Eksploatacyjne PAN
Powiązania:: https://bibliotekanauki.pl/articles/301830.pdf Link otwiera się w nowym oknie
Opis:: Miara zintegrowanej ważności (IIM) pozwala oceniać szybkość zmian wydajności systemu powstałych w wyniku przejścia elementu systemu z jednego stanu do drugiego. IIM pozwala rozważać scenariusze, w których szybkość przejścia elementu z jednego stanu do drugiego jest stała. Jest to jednak sprzeczne z założeniem degradacji, zgodnie z którym wydajność systemu obniża się, w związku z czym, szybkość przejścia może z upływem czasu ulegać zwiększeniu. Rozkład Weibulla opisuje żywotność danego elementu, co wykorzystuje się w wielu różnych zastosowaniach technicznych do modelowania złożonych zbiorów danych. W przedstawionej pracy, rozszerzono IIM uzyskując nową miarę ważności, która pozwala rozważać scenariusze, w których szybkość przejścia elementu z jednego stanu do drugiego w wyniku degradacji jest zależną od czasu funkcją rozkładu Weibulla. Przyjęto, że warunkowy rozkład prawdopodobieństwa elementu przebywającego w pewnym stanie jest rozkładem Weibulla, gdzie dany jest kolejny stan do którego ma przejść dany element. Badania nad nową miarą ważności umożliwiają identyfikację najważniejszych elementów podczas trzech różnych okresów czasu życia systemu, co odpowiada charakterystyce rozkładów Weibulla. Dla ilustracji, wyprowadzono pewne właściwości probabilistyczne i zastosowano rozszerzoną miarę ważności do analizy przykładu rzeczywistego układu śmigłowca.
The integrated importance measure (IIM) evaluates the rate of system performance change due to a component changing from one state to another. The IIM simply considers the scenarios where the transition rate of a component from one state to another is constant. This may contradict the assumption of the degradation, based on which system performance is degrading and therefore the transition rate may be increasing over time. The Weibull distribution describes the life of a component, which has been used in many different engineering applications to model complex data sets. This paper extends the IIM to a new importance measure that considers the scenarios where the transition rate of a component degrading from one state to another is a time-dependent function under the Weibull distribution. It considers the conditional probability distribution of a component sojourning at a state is the Weibull distribution, given the next state that component will jump to. The research on the new importance measure can identify the most important component during three different time periods of the system lifetime, which is corresponding to the characteristics of Weibull distributions. For illustration, the paper then derives some probabilistic properties and applies the extended importance measure to a real-world example (i.e., a propeller plane system).
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Investigation of low-sidelobe beampattern controlling methods for acoustic transmitting array of underwater vehicles
Autorzy:: He, Z.
Shi, Q.
Wu, S.
Tematy:: underwater unmanned vehicles
detecting and positioning
acoustic transducer
complex array
low-sidelobe beamforming; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/258624.pdf Link otwiera się w nowym oknie
Opis:: In underwater unmanned vehicles, complex acoustic transducer arrays are always used to transmitting sound waves to detect and position underwater targets. Two methods of obtaining low-sidelobe transmitting beampatterns for acoustic transmitting arrays of underwater vehicles are investigated. The first method is the boundary element model optimization method which used the boundary element theory together with the optimization method to calculate the driving voltage weighting vector of the array. The second method is the measured receiving array manifold vector optimization method which used the measured receiving array manifold vectors and optimization method to calculate the weighting vector. Both methods can take into account the baffle effect and mutual interactions among elements of complex acoustic arrays. Computer simulation together with experiments are carried out for typical complex arrays. The results agree well and show that the two methods are both able to obtain a lower sidelobe transmitting beampattern than the conventional beamforming method, and the source level for each transmitting beam is maximized in constraint of the maximum driving voltage of array elements being constant. The effect of the second method performs even better than that of the first method, which is more suitable for practical application. The methods are very useful for the improvement of detecting and positioning capability of underwater unmanned vehicles.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Feasibility study on the submerged floating tunnel in Qiongzhou Strait, China
Autorzy:: Jiang, B.
Liang, B.
Wu, S.
Tematy:: Submerged Floating Tunnel
Qiongzhou Strait
waterway crossing
design features
numerical analysis; Pokaż więcej
Wydawca:: Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Powiązania:: https://bibliotekanauki.pl/articles/258836.pdf Link otwiera się w nowym oknie
Opis:: Abstract: Currently, one of the challenging tasks for Chinese engineering community is to construct a water-way crossing of Qiongzhou Strait in the south of China. This project has also gained significant attention from researchers in academia. The study presented herein is centered on providing a feasible solution for ac-complishing the above mentioned task. Initially, different alternatives as the best location, judged on the basis of the environmental constraints, are studied. Then the comparison between various structural solutions such as suspension bridge, submarine tunnel and SFT is presented. Among these solutions, SFT appears to be a very suitable alternative for Qiongzhou Strait waterway crossing due to distinctive advantages, like shorter distance, lower cost, less impact on environment and navigation, etc. Based on the appropriate conception for cross sections, support systems, materials, joints and connection schemes, a numerical model is developed by means of the FEM software ANSYS/Fluent. It is then analyzed under the influence of different environmental loading conditions, varying the wave heights and lengths, current velocities and water depths, which are typical in Qiongzhou Strait. The numerical results reveal that the proposed SFT solution performs safely even under extreme weather conditions.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: The Bohr compactification, modulo a metrizable subgroup
Autorzy:: Comfort, W.
Trigos-Arrieta, F.
Wu, S.
Wydawca:: Polska Akademia Nauk. Instytut Matematyczny PAN
Powiązania:: https://bibliotekanauki.pl/articles/1208589.pdf Link otwiera się w nowym oknie
Opis:: The authors prove the following result, which generalizes a well-known theorem of I. Glicksberg [G]: If G is a locally compact Abelian group with Bohr compactification bG, and if N is a closed metrizable subgroup of bG, then every A ⊆ G satisfies: A·(N ∩ G) is compact in G if and only if {aN:a ∈ A} is compact in bG/N. Examples are given to show: (a) the asserted equivalence can fail in the absence of the metrizability hypothesis, even when N ∩ G = {1}; (b) the asserted equivalence can hold for suitable G and N with N closed in bG but not metrizable; (c) an Abelian group may admit two topological group topologies U and T, with U totally bounded, T locally compact,U ⊆ T, with U and T sharing the same compact sets, and such that nevertheless U is not the topology inherited from the Bohr compactification of ⟨ G, T⟩. There are applications to topological groups of the form kG for G a totally bounded Abelian group.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Mechanical Properties of Magnesium Alloys Produced by the Heated Mold Continuous Casting Process
Autorzy:: Okayasu, M.
Wu, S.
Tanimoto, T.
Takeuchi, S.
Tematy:: magnesium alloy
unidirectional solidification
continuous casting
mechanical properties
microstructural characteristic
stop magnezu
krystalizacja kierunkowa
odlewanie ciągłe
właściwości mechaniczne
charakterystyka mikrostrukturalna; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Czytelnia Czasopism PAN
Powiązania:: https://bibliotekanauki.pl/articles/381654.pdf Link otwiera się w nowym oknie
Opis:: Investigation of the tensile and fatigue properties of cast magnesium alloys, created by the heated mold continuous casting process (HMC), was conducted. The mechanical properties of the Mg-HMC alloys were overall higher than those for the Mg alloys, made by the conventional gravity casting process (GC), and especially excellent mechanical properties were obtained for the Mg₉₇Y₂Zn₁-HMC alloy. This was because of the fine-grained structure composed of the α-Mg phases with the interdendritic LPSO phase. Such mechanical properties were similar levels to those for conventional cast aluminum alloy (Al_84.7Si_10.5Cu_2.5Fe_1.3Zn₁ alloys: ADC12), made by the GC process. Moreover, the tensile properties (σ and ε_f) and fatigue properties of the Mg₉₇Y₂Zn₁-HMC alloy were about 1.5 times higher than that for the commercial Mg₉₀Al₉Zn₁-GC alloy (AZ91). The high correlation rate between tensile properties and fatigue strength (endurance limit: σ_l) was obtained. With newly proposed etching technique, the residual stress in the Mg₉₇Y₂Zn₁ alloy could be revealed, and it appeared that the high internal stress was severely accumulated in and around the long-period stacking-order phases (LPSO). This was made during the solidification process due to the different shrinkage rate between α-Mg and LPSO. In this etching technique, micro-cracks were observed on the sample surface, and amount of micro-cracks (density) could be a parameter to determine the severity of the internal stress, i.e., a large amount to micro-cracks is caused by the high internal stress.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Investigations on the Anisotropic g Factors of the $Ni^{3+}$ Site in $La_2Ni_{0.5}Li_{0.5}O_4$
Autorzy:: Kuang, M.
Wu, S.
Zhang, Z.
Song, B.
Tematy:: 76.30.Fc
71.70.Ch
75.10.Dg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1400149.pdf Link otwiera się w nowym oknie
Opis:: The anisotropic g factors $g_{∥}$ and $g_{⊥}$ of $La_2Ni_{0.5}Li_{0.5}O_4$ are theoretically investigated using the perturbation formulae of the g factors for a low spin $(S=1//2) 3d^7$ ion in tetragonally elongated octahedra. The studied $Ni^{3+} (3d^7)$ center arises from the original $Ni^{2+}$ capturing one hole by $Li^{+}$ doping. The positive anisotropy $\Delta g (= g_{⊥}-g_{∥})$ can be ascribed to the lowest $\text{}^2 A_{1g}$ state due to the obvious (about 0.14 Å) tetragonal elongation of the oxygen octahedron around the $Ni^{3+}$ site via the Jahn-Teller effect, and the effective magnetic moment is also interpreted in a uniform way. The calculated results show good agreement with the experimental data, and the imperfection of the previous studies based on various adjusted tetragonal energy splittings without correlating to the local structure of the magnetic center is thus overcome in this work.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Advanced Characterization of Material Properties on the Nanometer Scale Using Atomic Force Microscopy
Autorzy:: Fenner, M.
Wu, S.
Yu, J.
Huber, H.
Kienberger, F.
Tematy:: 77.55.-g
07.79.-v
68.37.Ps
68.37.Uv
07.57.Pt; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1490089.pdf Link otwiera się w nowym oknie
Opis:: We report recent advances in material characterization on the nanometer scale using scanning microwave microscopy. This combines atomic force microscopy and a vector network analyzer using microwave tip sample interaction to characterize dielectric and electronic material properties on the nanometer scale. We present the methods for calibration as well as applications. Scanning microwave microscopy features calibrated measurements of: (1) capacitance with attofarad sensitivity. For calibration a well characterized array of capacitors (0.1 fF to 10 fF) is used. The method is applied to determine the dielectric properties of thin organic films, (2) Semiconductor dopant density. Calibration is performed by imaging the cross-section of a standard sample with differently doped layers (dopant stair case) from $10^{16}$ atoms/$cm^3$ to $10^{20}$ atoms/$cm^3$.
Dostawca treści:: Biblioteka Nauki

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