Wyniki wyszukiwania - Biblioteka Nauki

1

Apparatus for Measuring the Bending Fatigue Properties of High Performance Polyethylene Fibre

100%

Cai G. , Shi X. , Yu W.

Fibres & Textiles in Eastern Europe

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2012

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tom Vol. 20, no. 4 (93)

37--40

EN

A test method for bending fatigue has been developed to determine the bending fatigue strength of fibres. This new equipment is capable of performing the bending fatigue testing of fibres under different pre-tensions, bending angles and temperatures. This article presents results from tests on single high performance polyethylene fibre (HPPE) to characterise its bending fatigue behaviour under cyclic loading and temperatures. The curve of the cyclic tension shows that the cyclic tension changes in periods during the cyclic bending process. The S-N and č-N curves indicated that the pre-tension and bending angle had great influences on the bending fatigue life of HPPE fibre. A CCD camera was utilised to allow observation of the bending fatigue fracture morphology of the fibre. It showed the fracture mechanism of the HPPE fibres. The bending fatigue life of HPPE fibre was tested at different temperatures to show that its bending fatigue strength is strongly influenced by the temperature.

PL

Opracowano metodę oceny wytrzymałości zmęczeniowej włókien polietylenowych przy zginaniu. Przewidziano możliwość badania włókien przy rożnym obciążeniu wstępnym, kącie zginania i temperaturze. Przeprowadzono próby badania włókien polietylenowych w różnych temperaturach i przy rożnym kącie zginania. Stwierdzono, że naprężenie zginające zmienia się okresowo podczas cyklicznego procesu zginania. Stwierdzono również, że wstępne naprężenie oraz kąt zginania mają istotny wpływ na wytrzymałość zmęczeniową badanych włókien. Kamerę CCD zastosowano dla obserwacji morfologii przełomu zmęczeniowego włókien, pozwalającego na identyfikację mechanizmu przełomu. Stwierdzono wyraźny wpływ temperatury, w której przeprowadzano próby.

2

Exploring root plasticity to resource patches based on swarm behavior

100%

Li S. , Liu X. , Wang M. , Yu W.

Acta Physiologiae Plantarum

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2016

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tom 38

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nr 08

3

Radiative Corrections to the Neutron Star Mass Inferred from QPO Frequencies

100%

Abramowicz M. A. , Kluźniak W. , Yu W.

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tom Vol. 61, No. 4

319--324

EN

The frequencies of kHz QPOs are widely interpreted as being indicative of the values of characteristic frequencies related to orbital motion around neutron stars, e.g., the radial epicyclic frequency. In regions directly exposed to the radiation from the luminous neutron star these frequencies change with the luminosity. Including radiative corrections will change the neutron star mass value inferred from the QPO frequencies. Radiative forces may also be behind the puzzling phenomenon of parallel tracks.

4

Analysis of root system architecture affected by swarming behavior

100%

Li S. , Yu W. , Liu X. , Wang M.

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2020

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tom 28

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nr 1

5

Image Despeckling Based on LMMSE Wavelet Shrinkage

100%

Cui Y. , Zhang T. , Yu W.

Przegląd Elektrotechniczny

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2012

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tom R. 88, nr 7b

269--272

EN

A low complexity method for suppressing speckle in synthetic aperture radar (SAR) images is proposed. This method doesn’t require the logarithmic transform and is an extension of the linear minimum mean square error (LMMSE) filter to the image wavelet representation. A spatially adaptive shrinkage function is obtained and each modified coefficient is decided separately. Simulation results for the simulated SAR images demonstrate the proposed method outperforms some representative SAR despeckling methods.

PL

Zaproponowano metodę poprawy jakości obrazu w radarach typu SAR. Bazuje ona na liniowym minimum średniej kwadratu błędu LMMSE filtru. Wykorzystano adaptacyjną funkcję zbieżną w przestrzeni i wszystkie współczynniki modyfikowane są niezależnie.

6

Distribution Networks State Estimation Based on Topological Contraction and Quality Tag

100%

Huang Y. , Liu D. , Xu W. , Yu W.

Przegląd Elektrotechniczny

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2012

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tom R. 88, nr 5b

1-6

EN

By processing a set of raw measurement data, it provides a real-time system state solution which is the basis of the advanced applications. Currently, the incomplete and poor quality of measurement data is the key factor to impacting state estimation of distribution network. With the help of decision tree theory, the bad data identification method which combines the historical data and remote data from IDP (Integrated Data Platform) and a data processing method is proposed. Algorithm uses the laws of the distribution network data logic to determine the logic of the distribution network. With the help of the theoretical framework of decision tree we can establish the data quality assessment system and fix those bad data so as to increase the quality of the input data. On the basis of data evaluation and fixing, by collecting grid-based data of distribution network and using topology analysis and contracting technology, we can contract the actual network to the state estimation calculation network which meets the observation demand. Quality labels are used to modify the weight of the least squares state estimation algorithm to improve the accuracy of state estimation. Based on the status of data in city distribution network, a proper measurement data detecting and fixing method as well as topology contracting method is proposed. Two real cases of certain central power supply area in Shanghai have verified the effectiveness and feasibility of the method.

PL

W artykule zaproponowano metody badania stanu sieci dystrybucyjnej w czasie rzeczywistym. Metodę zilustrowano na przykładzie dwóch obszarów sieci zasilającej w Szanghaju.

7

On the number of positive solutions to a class of integral equations

100%

Wang L. , Yu W. , Zhang L.

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tom Vol. 32, no 2

383-395

EN

By using the complete discrimination system for polynomials, we study the number of positive solutions in C[0,1] to the integral equation phi(x) = integral[...] k(x,y)phi^n(y)dy, where k(x,y) = phi1(x)phi1(y)+phi2(x)phi2(y),[phi]i(x) > 0,[phi]i(y) > 0,0 < x,y < 1,i = 1,2, are continuous functions on [0,1], n is a positive integer. We prove the following results: when n = 1, either there does not exist, or there exist infinitely many positive solutions in C[0,1]; when n [is greater than or equal] 2, there exist at least 1, at most n + 1 positive solutions in C[0,1]. Necessary and sufficient conditions are derived for the cases: 1) n = 1, there exist positive solutions; 2) n [is greater than or equal to] 2, there exist exactly m (m belongs to {1,2,..., n + 1}) positive solutions. Our results generalize the ones existing in the literature, and their usefulness is shown by examples.

8

Research on the influence of driving harmonic on electromagnetic field and temperature field of permanent magnet synchronous motor

100%

Qiu H. , Yu W. , Li Y. , Yang C.

Archives of Electrical Engineering

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2017

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tom Vol. 66, nr 2

295--312

EN

At present, the drivers with different control methods are used in most of permanent magnet synchronous motors (PMSM). A current outputted by a driver contains a large number of harmonics that will cause the PMSM torque ripple, winding heating and rotor temperature rise too large and so on. In this paper, in order to determine the influence of the current harmonics on the motor performance, different harmonic currents were injected into the motor armature. Firstly, in order to study the influence of the current harmonic on the motor magnetic field, a novel decoupling method of the motor magnetic field was proposed. On this basis, the difference of harmonic content in an air gap magnetic field was studied, and the influence of a harmonic current on the air gap flux density was obtained. Secondly, by comparing the fluctuation of the motor torque in the fundamental and different harmonic currents, the influence of harmonic on a motor torque ripple was determined. Then, the influence of different current harmonics on the eddy current loss of the motor was compared and analyzed, and the influence of the drive harmonic on the eddy current loss was obtained. Finally, by using a finite element method (FEM), the motor temperature distribution with different harmonics was obtained.

9

Study on the Origins of Textile Materials on the Basis of Analysis of Related Hard Relics from Chinese Excavations

100%

Tao Y. , Wang Q. , Yu W.

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tom Vol. 25, no. 1 (121)

108--112

EN

Textile materials are widely available in nature, and the original time when humans started to use them must have been very early. However, they also easily aged, and most of the ancient ones had decomposed and disappeared thoroughly before we could find them, resulting that the remaining textile relics cannot reflect entirely the origins of textile materials. Fortunately large numbers of indirect evidence related to ancient textile materials can be found in many unearthed culture relics belonging to the Stone Age. Starting from the basic survival needs of primitive man, in this article, we analysed related hard relics from Chinese excavations made of stone, wood, bone, and so on. And based on this, the time of origin of the textile materials was further speculated upon.

PL

Materiały włókniste są stosowane od bardzo dawna. Jednakże tekstylia szybko się starzeją i większość starożytnych materiałów uległo rozkładowi całkowicie znikając zanim je odnaleziono, co powoduje błędy w datowaniu początku stosowania tekstyliów. Dużą liczbę dowodów pośrednich związanych z dawnymi tekstyliami można znaleźć w wielu odnalezionych reliktach kultury pochodzących z różnych epok, w tym epoki kamiennej. W artykule przeanalizowano artefakty pochodzące z chińskich wykopalisk wykonane z kamienia, drewna, kości, ceramiki itp. Na podstawie tychże analiz można określić, z którego okresu pochodzą tekstylia.

10

Robust identification by dynamic neural networks using sliding mode learning

100%

Poznyak A. S. , Yu W. , Sanchez E. N. , Sira-Ramirez H.

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1998

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tom Vol. 8, no 1

135-144

EN

The problem of identification of continuous, uncertain nonlinear systems in the presence of bounded disturbances is implemented using dynamic neural networks. The proposed neural identifier guarantees a bound for the state estimation error. This bound turns out to be a linear combination of internal and external uncertainty levels. The neural net weights are updated on-line by a learning algorithm based on the sliding mode technique. To the best of the authors' knowledge, such a learning scheme is proposed for dynamic neural networks for the first time. Numerical simulations illustrate its effectiveness, even for highly nonlinear systems in the presence of important disturbances.

11

Influence of different rotor magnetic circuit structure on the performance of permanent magnet synchronous motor

100%

Qiu H. , Yu W. , YANG C. , Yi R.

Archives of Electrical Engineering

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2017

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tom Vol. 66, nr 3

583--594

EN

In order to compare the performance difference of the permanent magnet synchronous motors (PMSM) with different rotor structure, two kinds of rotor magnetic circuit structure with surface-mounted radial excitation and tangential excitation are designed respectively. By comparing and analyzing the results, the difference of the motor performance was determined. Firstly, based on the finite element method (FEM), the motor electromagnetic field performance was studied, and the magnetic field distribution of the different magnetic circuit structure was obtained. The influence mechanism of the different magnetic circuit structure on the air gap flux density was obtained by using the Fourier theory. Secondly, the cogging torque, output torque and overload capacity of the PMSM with different rotor structure were studied. The effect mechanism of the different rotor structure on the motor output property difference was obtained. The motor prototype with two kinds of rotor structure was manufactured, and the experimental study was carried out. By comparing the experimental data and simulation data, the correctness of the research is verified. This paper lays a foundation for the research on the performance of the PMSM with different magnetic circuit structure.

12

The transcript profiles of a putative early light-induced protein (ELIP) encoding gene in Ginkgo biloba L. under various stress conditions

88%

Wang H. , Cao F. , Li G. , Yu W. , Aitken S. N.

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nr 01

EN

An early light-inducible protein (GbELIP) isolated from immature ginkgo leaves by rapid amplification of cDNA ends method contains a 570 bp open reading frame encoding a 189 amino acid protein, with significant homology to early light-inducible proteins from other plant species. The genomic DNA of GbELIP gene contains three exons and two introns. Southern blotting revealed that GbELIP is a singlecopy gene in ginkgo. Light, defense and stress responsive element were found in the promoter region of GbELIP. GbELIP expressional patterns were detected by Real-time PCR at various conditions. ELIP expressions were variable at different time points of 1 day and increasing significantly at the commencement of light illumination then dropping to a basal level gradually. ELIP expression in small size leaves (1–1.5 cm width and 7-day age) was higher then middle (2–3 cm width and 15-day age) and large (4 cm width and 30-day age) size leaves. It revealed that ELIP expression was under the control of developmental regulation. Under temperature and light intensity treatments, GbELIP transcripts accumulation may relate to photoinhibition. The peak expression of GbELIP appeared later by chilling than heating Meanwhile, GbELIP expression under high light was higher than low light at both two temperatures. GbELIP expression was also increased by wounding and methyl jasmonate (Me-JA) treatment, but not corresponded with increasing malondialdehyde (MDA) concentration. In conclusion, GbELIP appears to be induced by an imbalance between chlorophyll formation and degradation during development or under abiotic stress. These results suggest that GbELIP may function in response to environmental signals, possibly regulating responses to abiotic stresses.

13

A Novel EBG Structure with Embedded Meander Bridge and Its Applications on SI and PI

75%

Yan Z. , Yu W. , Cao J. , Wang W. , Han Y. , Rahman T.

Przegląd Elektrotechniczny

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2012

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tom R. 88, nr 7b

294--299

EN

This paper proposes an embedded meander bridge planar EBG structure, which can effectively suppress ultra-wideband (UWB) simultaneous switching noise (SSN) in power/ground plane pairs. This paper demonstrates that the valid -30 dB suppression bandwidth of the novel EBG structure is from 500 MHz to 14.5 GHz, covering a range of 14GHz. Furthermore, the effects of the EBG power plane on signal integrity (SI) is investigated. The design rules of the signal lines over the EBG power/ground plane pairs are also studied. The simulated and measured results are compared to verify the performance.

PL

W artykule opisano mostkową strukture EBG typu meander która umożliwia skuteczne tłumienie szumów szerokopasmowych. Układ umożliwia tłumienie o 30 dB sygnałów w paśmie 500 MHz – 14.5 GHz.

14

Investigations of mechanical properties of API P110 steel casing tubes operated in deep-sea sour condensate well conditions

75%

Zilin Y. , Yu W. , Xuefeng Y. , Anping G. , Rong Z. , Yanjie J.

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nr 3

15

Comparative chromosomal studies in Rhinolophus formosae and R. luctus from china and Vietnam: elevation of R. l. lanosus to species rank

63%

Volleth M. , So N. T. , Wu Y. , Li Y. , Yu W. , Lin L.-K. , Arai S. , Trifonov V. , Liehr T. , Harada M.

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nr 1

EN

For the majority of Rhinolophus species a karyotype consisting of either 58 or 62 chromosomes was reported. The members of the R. trifoliatus clade are therefore distinguished from other rhinolophids by low diploid chromosome numbers (2n) and a high rate of chromosomal changes. Recently, based on cytogenetic characters, a cryptic species, R. luctoides, was described and a subspecies, R. luctusmorio, was elevated to species rank. In the present work, the karyotypes of a male bat from Vietnam and a female one from China, both classified as R. luctus by morphological characters, were studied by G-banding and fluorescence in situ hybridization with whole chromosome painting probes derived from Aselliscus stoliczkanus. In the male specimen from Vietnam, the composition of the 15 autosomal bi-armed pairs (2n = 32, FN = 60) is identical to that of R. luctoides from Malaysia. For reason of differences in body size and baculum length as well as in skull morphology, this specimen is provisionally treated as R. cf. luctoides. The karyotype of the female specimen from Sichuan province, China, differs from R. luctoides by a whole arm reciprocal translocation resulting in an altered arm composition of pairs 3 and 4. For this reason, the elevation of the Chinese subspecies of R. luctus, i.e. R. lanosus, to species rank is suggested. The karyotype of the endemic Taiwanese species R. formosae with a diploid number of 2n = 52 is mainly composed of acrocentric autosomal pairs. Of the five bi-armed pairs, only the two smallest show the same arm composition as found in the 2n = 32 karyotypes of other members of the R. trifoliatus clade. The composition of the remaining three bi-armed pairs is unique and represents an apomorphic feature for R. formosae.