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EN
In recent years, with the progress of science, more and more detection methods are being used in various fields. However, the nondestructive testing of nonmetallic materials still needs further study. In this paper, an analysis of the time domain characteristics of rubber materials using terahertz detection technology was carried out, obtaining different defect rubber material spectral characteristics as well as imaging results and data. The results show that the THz spectrum imaging technique can detect the thickness of rubber material in the 0.1 ~ 4.0 terahertz band, and the image is clear and the resolution high. Meanwhile the time domain waveform obtained is sensitive to the debonding defects of the sample rubber, is suitable for judging the overall performance of the rubber inner defect detection, and can provide the scientific basis for rubber material performance.
PL
W artykule przedstawiono analizę charakterystyk materiałów gumowych z wykorzystaniem technologii wykrywania terahercowego, uzyskując różne charakterystyki spektralne defektów gumy, a także wyniki i dane obrazowe. Wyniki pokazały, że technika obrazowania widma THz może wykrywać grubość materiału gumowego w paśmie 0,1 ~ 4,0 terahercowym, a obraz jest wyraźny i ma wysoka rozdzielczość. W międzyczasie otrzymany przebieg domeny czasu jest wrażliwy na defekty badanej gumy, jest odpowiedni do oceny ogólnej wydajności wykrywania wewnętrznego defektu gumy i może zapewnić podstawy dla oceny właściwości materiału gumowego.
EN
The hybrid structures show excellent performance on vibration reduction for ship, aircraft and spacecraft designs. Meanwhile, the topology optimization is widely used for structure vibration reduction and weight control. The design of hybrid structures considering simultaneous materials selection and topology optimization are big challenges in theoretical study and engineering applications. In this paper, according to the proposed laminate component method (LCM) and solid isotropic microstructure with penalty (SIMP) method, the mathematical formulations are presented for concurrent materials selection and topology optimizations of hybrid structures. Thickness distributions of the plies in laminate components are defined as materials selection design variables by LCM method. Relative densities of elements in the components are defined as topology design variables by SIMP method. Design examples of hybrid 3-bar truss structures and hybrid floating raft with vibration reduction requirements verified the effectiveness of the presented optimization models.
EN
The core idea of reliability design is to mitigate the product’s failure modes. However, for the cross-links among potential failure modes of a complex product, it is very difficult to establish the mapping relationship between failure modes mitigation and quantitative values of reliability, and the decision of failure modes mitigation have to be performed by virtue of experience, which always increase design period. In order to solve these problems, a novel logic-based approach for failure modes mitigation control and quantitative system reliability analyses is provided. Firstly, a hybrid of active and passive control process of reliability design is proposed. Secondly, a novel concept of failure modes correlation set (FMCS) and a determination approach based on deductive theory are presented. According to the changes in failure modes probabilities of occurrence, the reliability formulas of the components and assemblies are provided to depict the effects of failure mode mitigation on reliability of components and assemblies. And then the FMCS mitigation sequence is decided to determine reliability design activities. Thirdly, a closed control process of FMCS mitigation is provided integrated with logic decision method. By exposing the design of a helicopter fuel system, the present study demonstrates that all approaches are feasible, and the relationship between reliability parameters and qualitative design exists. Hence the failure modes mitigation could be controlled for the achievement of quantitative reliability requirements.
PL
Podstawowym problemem w procesie projektowania niezawodności jest ograniczenie przyczyn uszkodzeń produktu. Jednakże, w przypadku sieci połączeń pomiędzy możliwymi przyczynami uszkodzeń złożonego produktu, trudno jest ustalić mapę zależności pomiędzy ograniczaniem przyczyn uszkodzeń i ilościowymi wartościami niezawodności, a decyzje względem ograniczania przyczyn uszkodzeń muszą bazować na własnym doświadczeniu, co znacznie wydłuża okres projektowania. W celu rozwiązania powyższych problemów, zaproponowano oryginalną, opartą na logice, metodę kontroli ograniczania przyczyn uszkodzeń i ilościowej analizy niezawodności systemu. Na wstępie, zaproponowano mieszany proces aktywnej i pasywnej kontroli niezawodności projektu. Następnie, zaprezentowano oryginalną koncepcję zbioru korelacji przyczyn uszkodzeń (FMCS) i metodę oznaczania opartą o teorię dedukcji. Na podstawie zmian dotyczących prawdopodobieństwa występowania przyczyn uszkodzeń, określono wzory niezawodności części i układów w celu pokazania wpływu ograniczania przyczyn uszkodzeń na niezawodność części i układów. Określono następnie ograniczającą sekwencję FMCS, ażeby ustalić założenia dla projektowania niezawodności. Na koniec zaprezentowano zamknięty proces kontroli ograniczania FMCS w powiązaniu z logiczną metodą podejmowania decyzji. Analizując pod tym kątem projekt systemu paliwowego helikoptera, wykazano w niniejszej pracy przydatność wszystkich powyższych metod, jak również związek pomiędzy parametrami niezawodności a projektowaniem jakościowym. Dlatego też ograniczanie przyczyn uszkodzeń powinno być kontrolowane w celu osiągnięcia wymaganej niezawodności ilościowej.
EN
In the acoustic fatigue experiment for hypersonic vehicle in simulated harsh service environment on ground, acoustic loads on the surface of test pieces of the vehicle need to be measured. However, for the normal microphones without high temperature resistance ability, the near field sound measurement cannot be achieved. In this work, on the basis of previous researches, an acoustic tubes array is designed to achieve the near field measurement of acoustic loads on the surface of the test piece in the supersonic airflow with high temperature achieved by coherent jet oxygen lance. Firstly, the process of designing this acoustic tubes array is introduced. Secondly, the equality of phase differences at the front and at the end of the tubes is stated and proved using a phase differences test with an acoustic tubes array whose design is presented in this text; therefore, the phase differences of signals acquired by microphones can be directly applied to beamforming algorithm to determine the acoustic load source. Finally, using above mentioned acoustic tubes array, measurement of acoustic load, with and without a test piece in the supersonic airflow made by the coherent jet oxygen lance, is conducted respectively, and the measurements results are analyzed.
EN
Through working out a indoor plan of the effects of deicing salt on adhesion properties between asphalt mortar and aggregate, based on innovative experiments with water boiled method to analysis of the effects of deicing salt on adhesion properties between asphalt and basalt and the effects of deicing salt on adhesion properties between SBS modified asphalt and basalt. The results show that specimens have a greater difference in adsorption capacity with the different effect solutions, through the effect of CaCl2�ANC, the adhesion properties of asphalt and mortar and aggregate have been improved to some extent. In addition, through the effect of different deicing salt, the discrete levels of adsorption capacity of specimen different are different, through the effect of CaCl2, adhesion improving while the instability of adsorption capacity have appeared, but NC is relatively stable. Therefore, comprehensive consideration of the appropriate choice of the type of deicing salt can effectively reduce the effects of deicing salt on adhesion properties between asphalt mortar and aggregate.
PL
Artykuł analizuje wpływ soli użytej do odlodzenia na właściwości przyczepności między asfaltem a kruszywem. Odpowiedni dobór soli odmrażającej ma istotny wpływ na tę przyczepność.
6
Content available remote Denoising and detrending of measured oscillatory signal in power system
EN
This paper presents a novel method for denoising and detrending of oscillatory signal measured from wide area measurement system (WAMS) using empirical mode decomposition (EMD) and time-frequency analysis. First of all, the measured signal is decomposed into a set of intrinsic mode functions (IMFs) by EMD. Next, the IMFs are divided into three parts based on their time and frequency distributions. Then, the noise and higher frequency components, trend components and meaningful oscillation modes are identified respectively. The proposed method are validated by the actual measured signal from WAProtector and the estimated trend is confirmed by comparing with the sliding linear trend estimated method and other nonlinear trend estimated methods.
PL
W artykule zaprezentowano nową metodę usuwania szumu z sygnału okresowego w systemach WAMS. W pierwszej kolejności przeprowadza się dekompozycję sygnału na funkcje, które następnie dzielone są na trzy części w zależności od rozkładu czasowoczęstotliwościowego.
EN
In woody perennials, leaf structure and biochemistry vary with tree age under changing environments. However, the related eco-physiological mechanisms have not been elucidated yet. In this study, we investigated agerelated responses of juvenile and mature subalpine fir trees (Abies faxoniana Rehder & E.H. Wilson.) growing at altitudes between 2,500 and 3,500 m in the Wanglang Natural Reserve in southwest China, to study the adaptive strategies of different age trees to suit changing environments. We found that there were distinct age- and altituderelated changes in the structural and biochemical characteristics of leaves. At all altitudes, mature trees exhibited higher area- and mass-based leaf nitrogen content (N[area], N[mass]), leaf mass per area (LMA) and stable isotope carbon composition ([delta^13]C), and a lower chlorophyll (Chl) content than those juvenile trees, except for N[mass] at 3,000 m as well as LMA at 2,750 m, where the values of N[mass] and LMA in mature trees were slightly lower than those in juvenile trees. Furthermore, leaf characteristics showed significant differences in the change rates with altitude between different age groups. Our results indicated that assimilative organs in mature trees do not suffering from nutrient deficiency and that juvenile and mature trees possess different adaptive growth strategies under changing environments, as indicated by higher leaf N content in mature trees and the opposite patterns of LMA and Chl content between two age groups. We also concluded that juvenile could be more sensitive to global warming due to a greater altitudinal influence on the leaf traits in juvenile trees than those in mature trees.
EN
In many applications, clusters tend to have vague or imprecise boundaries. It is desirable that clustering techniques should consider such an issue. The decision-theoretic rough set (DTRS) model is a typical probabilistic rough set model, which has the ability to deal with imprecise, uncertain, and vague information. This paper proposes an autonomous clustering method using the decision-theoretic rough set model based on a knowledge-oriented clustering framework. In order to get the initial knowledge-oriented clustering, the threshold values are produced autonomously based on semantics of clustering without human intervention. Furthermore, this paper estimates the risk of a clustering scheme based on the decision-theoretic rough set by considering various loss functions, which can process the different granular overlapping boundary. An autonomous clustering algorithm is proposed, which is not only experimented with the synthetic data and the standard data but also applied in the web search results clustering. The results of experiments show that the proposed method is effective and efficient.
EN
The method of high-performance liquid chromatography (HPLC) with diode array detector (DAD) was used and validated for the simultaneous determination of nine flavonoids (rutin, myricetin, quercitrin, quercetin, luteolin, genistein, kaempferol, apigenin, and isorhamnetin) in beagle dog plasma. Plasma sample was pre-treated with acetonitrile (containing 0.05% formic acid). Chromatographic separation was performed on a kromasil C18 column (250 × 4.6 mm, 5 µm) maintained at 35 °C. The mobile phase was a mixture of methanol and 0.2% formic acid with a step linear gradient. At 1.0 mL min-1 flow rate, the eluent of other eight flavonoids was detected simultaneously at 360 nm with good separation except genistein (detected at 254 nm). Under optimum conditions, the correlation coefficient between the peak area and the concentrations for each analyte was all above 0.999. The intra-day and inter-day precisions were less than 10% for all analytes. The limit of detection and the limit of quantification for the selected nine flavonoids were 0.006–0.03 and 0.02–0.12 g mL, -1 respectively. The extracted recoveries of selected nine flavonoids were 74.02%–99.37%. The assay has been successfully applied to determine concentrations of nine flavonoids in plasma from beagle dog after being intravenously administrated Ginkgo biloba extract.
EN
A novel-designed compact, ultrafast electro-optic slow light modulator based on two-dimensional coupled photonic crystal resonator arrays (2D CPCRAs) has been studied. The 2D CPCRAs, realized in silicon-on-insulator (SOI) slabs with nonlinear polymer as filling material, exhibit a single guided mode with low group velocity in all crystal directions. We realize fast electro-optic tuning of the slow mode in a wide frequency range with low modulating voltage in this structure. Numerical analysis shows that the frequency shift is nearly linearly increasing with the applied voltage. In addition, for a certain frequency, changing the modulating voltage can tune the group delay of slow mode easily.
EN
This paper presents a linear matrix inequality (LMI) method for the design of the wide-area time-delay damping (WATDD) controller of static synchronous series compensator (SSSC)-type flexible ac transmission system (FACTS) device to enhance the power stability of the interconnected power systems. Firstly, in order to reveal the single-input multi-output (SIMO) characteristic of the open-loop power system with SSSC-type FACTS device, the prediction error estimation (PEE) algorithm based system identification method is applied to fit a special SIMO linear model. Then, based on the robust control theory and LMI method, the identified linear model is formulated as the standard control problem with the time-delay of the input signals of the WATDD controller, and combined with the designed state observer for the input state variables of the WATDD controller, the control parameters are optimized by the LMI iterative solution algorithm. Finally, the nonlinear simulation on the typical 2-area 4-machine system installed with SSSC-type WATDD controller is performed to verify the LMI-based design method and the proposed SSSC-type WATDD controller.
PL
W artykule przedstawiono metodę nierówności matrycy liniowej (LMI) do projektowania kontrolera z opóźnieniem kompensatora szeregowego synchronicznego (SSSC) elastycznego systemu przesyłowego prądu przemiennego (FACTS) w celu zwiększenia stabilności wzajemnie połączonych systemów zasilania. Po pierwsze, dopasowano specjalny model liniowy SIMO do charakterystyki otwartego systemu z urządzeniem SSSC-FACTS. Następnie, w oparciu o odporną teorię sterowania i metodę LMI, opisano zidentyfikowany model jako standardowy problem sterowania z opóźnieniem czasowym sygnałów wejściowych kontrolera WATDD i połączono go z utworzonym obserwatorem stanu wielkości wejściowych kontrolera WATDD - parametry sterowania są optymalizowane iteracyjnie za pomocą algorytmu LMI. W końcu, przeprowadzono symulację nieliniową typowego systemu (2-area 4-machine system) z kontrolerem SSSC typu WATDD w celu weryfikacji zaproponowanej metody.
EN
For the demand of harmonic suppression and reactive power compensation of large-power electrical ac/dc power converter systems, this paper presents a class of new auto-inductive and harmonic-suppression (AIHS) transformers and a corresponding inductive filtering method, proposes a general model and its harmonic model constructed by the transformer windings and the full-tuned circuit under the specific harmonic frequencies, and establishes the harmonic equivalent circuit model. Based on this, according to the established mathematical model, this paper reveals the filtering mechanism of the new inductive filtering method, and obtains the necessary impedance condition for the new transformer and the tuned condition for the full-tuned circuit to suppress the main harmonic currents in the secondary windings. Furthermore, the influence of the impedance parameters on the inductive filtering effect is analysed. Finally, the experimental results verify the correctness of theoretical analysis, and present the good inductive filtering performance that the new transformer has.
PL
W celu tłumienia harmonicznych i kompensacji mocy biernej w systemach przekształtnikowych o dużej mocy AC / DC, w niniejszej pracy zaprezentowano nową klasę transformatorów auto-indukcyjnych i tłumienia harmonicznych (AIHS) i odpowiednie metody filtrowania, zaproponowano ogólny model i model harmoniczny - skonstruowany przy pomocy uzwojenia transformatora i układu dostrojonego do wybranych częstotliwości harmonicznych oraz pokazano ekwiwalentny model harmoniczny tego układu. Na tej podstawie, zgodnie z ustalonym modelem matematycznym, pokazuje się mechanizm filtrowania dla tej nowej metody filtrowania indukcyjnego i wyprowadza się warunek konieczny dla układu w pełni dostrojonego w celu zlikwidowania głównych prądów harmonicznych w uzwojeniu wtórnym transformatora. Ponadto, jest analizowany wpływ parametrów impedancji na działanie filtrowania indukcyjnego. Wreszcie, przedstawiono wyniki badań sprawdzenia poprawności analizy teoretycznej i przedstawiono dobre wyniki filtrowania indukcyjnego za pomocą tego nowego transformatora.
EN
Eu3+-doped bismuth borate based glasses with various contents of WO3 were fabricated by melt quenching. Optical properties of Eu3+ ions in these ternary systems and their dependence on the WO3 content were investigated: absorption and emission spectra were studied as the WO3 molar ratio was adjusted from 1 to 5 mol %. The Judd-Ofelt parameters were calculated from the emission spectra and expressed in terms of reduced matrix U t (t = 2, 4, 6) characters for optical transitions. The influence of WO3 content on the Judd-Ofelt intensity parameter ?2 was also investigated. Experimental results lead us to conclude that the optimum luminescence of Eu3+-doped bismuth borate based glasses is achieved if the WO3 content is 3 mol %.
EN
The effect of annealing at 720-920 K under enhanced pressure (up to 1.1 GPa) in argon ambient on electrical properties of the surface layer of the Czochralski-grown silicon (Cz-Si) subjected to neutron irradiation (doses of up to 1x10>sup>17 cm-2, E = 5 MeV) or germanium doping (doping level 7x1017 cm-3) was investigated by electrical C-V, I-V and admittance method. The stress-induced decrease in electron concentration was observed in both p- and n-type samples after neutron irradiation and annealing under a pressure of 1.1 GPa at 720 K for 10 hours, while in the germanium doped samples an ascending dependence of the creation of thermal donors and lack of dependence of new donors on hydrostatic pressure was observed. The effects observed can be explained as resulting, among others, from the irradiation-induced defects (generation of thermal acceptors) and pressure stimulated creation of thermal donors in germanium-doped silicon.
EN
A new spherical macroporous epoxy-tetraethylenepentamine chelating resin was synthesized from epoxy resin simply and rapidly. Its adsorption-desorption properties were studied in detail. Au(I[l), Pt(IV) and Pd(IV) was quantitatively adsorbed on the resin from aqueous solutions of pH = 2.0-4.0. Adsorption capacities of the resin towards Au(III), Pt(IV) and Pd(IV) were 8.9 x 10-4, 7.6 x 10-4, and 9.6 x 10-4 mol per gram of the epoxytetraethylenepentamine chelating resin, respectively. The adsorbed metal ions were nextdesorbed at 50-60°C using 3% thiourea solution in 2 mol L-1 HCI. Other metal ions caused little interference during preconcentration and simultaneous determination ofAu(IIl). Pt(IV) and Pd(IV) by ICP-AES. Au(III), Pt(IV) and Pd(IV) could be determined at the co
PL
Opisano prostą i szybką metodę syntezy z żywicy epoksydowej kulistego, makroporowatego jonitu chelatującego epoksy-tetraetylenopentaarninowego. Zbadano szczegółowo jego własności adsorpcyjno-desorpcyjne. Au(III), Pt(IV) i Pd(IV) były ilościowo zatrzymywane na jonicie z roztworów wodnych o pH = 2.0r4.0. Pojemności adsorpcyjne jonitu w stosunku do Au(III), Pt(IV) i Pd(IV) wynosiły odpowiednio: 8.9 x l 0-4, 7.6 x l 0-4 i 9.6 5 10-4 mol na gram jonitu. Zatrzymane jony desorbowano w temp. 50-60°C za pomocą 3% roztworu tiomocznika w 2 mol L-4 HCI. Inne jony miały mały wpływ na przebieg zatężania i jednoczesnego oznaczania Au(III), Pt(IV) i Pd(IV) za pomocą ICP-AES. Możliwe było oznaczenie Au(III), Pt(IV) i Pd(IV) nawet na poziomie stężeń l ng mL-1 przy stopniu zatężenia równym 300.
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