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1

Real-time optical demultiplexing with the chirped pulses

Li Y., Zhang X., Yuan J., Kang Z., Sang X., Kang S., Kang X., Yan B., Wang K., Yu C.

Optica Applicata

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2018

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Vol. 48, nr 4

621--632

EN

A scheme for real-time optical demultiplexing is proposed by utilizing the time-broadened and linearly chirped pulses instead of the conventional mode-locked pulses. The copies of the optical-time-division-multiplexed signal are acquired through a dual-pump parametric gate and used as the parametric multicast block. Simulation results show that the demultiplexing from 160 Gb/s down to sixteen 10 Gb/s tributaries can be achieved only by using a sampling source of 10 GHz. The proposed scheme can effectively reduce the complexity of parallel processing, and find important applications in the high-speed all-optical signal processing.

2

Microstructure and Impact Toughness of Offshore Steel

Cheng T.-C., Yu C., Yang T.-C., Huang C.-Y., Lin H.-C., Shiue R.-K.

Archives of Metallurgy and Materials

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2018

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Vol. 63, iss. 1

167--172

EN

This study focused on the effects of microstructures on the low-temperature impact toughness of directly water-quenched offshore steel. Martensite dominated the microstructure directly below the quenched surface. In contrast, mainly lower bainite, martensite, and low amount of ferrite were observed in the central region of the quenched specimen. The ductile to brittle transition temperature of tempered martensite was significantly lower than that of a bainite-dominated microstructure. It is found that low-angle boundaries within the bainite packets greatly impair the low-temperature impact toughness of the steel. The absence of high-angle boundaries in the lower bainite packets significantly deteriorates the low-temperature impact energy of offshore steel.

3

Selective adsorption of anionic polyacrylamide onto ultra-low ash coal and kaolinite

Zou W., Yu C., Sun C., Cao Y.

Physicochemical Problems of Mineral Processing

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2016

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Vol. 52, iss. 2

738--753

EN

To study the selectivity of polyacrylamide in the selective floc flotation of fine coal, adsorption of anionic polyacrylamide (PAM A401) onto ultra-low ash coal and kaolinite was studied, including the adsorption thermodynamics, floc size distribution and wettability changes. The thermodynamics of the adsorption process at the low concentration of 0-16 mg/dm3 of PAM A401 were studied at different contact times, doses, temperatures and pH values. Thermodynamic parameters of ΔGo, ΔHo, ΔSo and Ea were evaluated to understand the nature of the adsorption process. The results indicated that PAM A401 was selectively adsorbed onto ultra-low ash coal rather than kaolinite. Physical adsorption was the predominant mechanism, and the adsorption of PAM A401 at 12 mg•dm-3 onto coal was 2.15-fold larger than the adsorption on kaolinite. After the adsorption of PAM A401, the lipophilic hydrophilic ratio (LHR) of coal decreased from 9.23 to 7.28, indicating that the coal became less hydrophobic than before. In contrast, the LHR of kaolinite increased from 1.44 to 1.65. Floc size measurements showed that the d10, d50 and d90 of coal flocculated by PAM A401 (at 12 mg/dm3, pH 6.5) were 3.18, 2.76 and 2.59-fold greater than the corresponding levels of these parameters for kaolinite flocs, respectively.

4

Double tunneling induced transparency in the asymmetry quantum dot molecules

Yu C., Huang H., Zhang L., Xu D.

Optica Applicata

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2016

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Vol. 46, nr 3

473--481

EN

Using the density matrix theory, we have studied the double tunneling induced transparency slow light in the double asymmetry quantum dot molecules. With applied electric field, double tunneling induced transparency occur in the same time. Four absorption peaks are found near the resonance energy level in the absorption spectrum and the absorption peak can be tuned by the applied electric field. The velocity and bandwidth of the multiple-windows slow light can also be controlled by the applied electric field. In our model, with Te =0.1meV, we can get about 0.001c and 20GHz bandwidth in each transparency window. Such a property may be applied in all optical buffers, optical switching and filter.

5

Three Dimensional Crustal Density Structure of Central Asia and its Geological Implications

Yang W., Chen Z., Hou Z., Yu C.

Acta Geophysica

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2016

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Vol. 64, no. 5

1257--1274

EN

This paper introduces the scale-depth law of multi-scale wavelet analysis for regional gravity data processing, and presents the results of its application to Central Asia for computation of the 3D crustal density structures. The wavelet analysis method is applied for characterizing 3D crustal density structure, producing five maps of density disturbance corresponding to different depths of equivalent layers in the crust. The results provide important evidence for the study of crustal structures and mass movement in Central Asia: (i) the small-scale and intensive linear density disturbances in the upper crust indicate Phanerozoic orogenic belts; (ii) there exists a horseshoe-shaped low-density belt in the middle crust coinciding with the Kazakhstan orocline; (iii) there is a very low density zone in the lower crust, extending from western Kunlun to Tianshan, probably indicating a lower-crust flow; (iv) there are a few lowdensity spots in the middle crust, which might be caused by low-density mass squeezing upward from the lower crust flows.

6

Application of Genetic Algorithm for Feature Selection in Optimisation of SVMR Model for Prediction of Yarn Tenacity

Abakar K. A. A., Yu C.

Fibres & Textiles in Eastern Europe

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2013

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Vol. 21, no. 6 (102)

95--99

EN

A proposed hybrid genetic algorithm (GA) approach for feature selection combined with support vector machines for regression (SVMR) was applied in this paper to optimise a data set of fibre properties and predict the yarn tenacity property. This hybrid approach was compared with a noisy model of SVMR that used all the data set of fibre properties as input in the prediction. The GA for feature selection was used as the preprocessing stage that aimed to find and select the best attributes or variables that most effect or are related to the prediction of yarn tenacity. The hybrid approach showed better predictive performance than the noisy model. However, the results indicated the suitability of GA for feature selection in the choice of the best fibre property attributes that give the preferred performance and high accuracy in the prediction of yarn tenacity.

PL

Zaproponowany system hybrydowy łączący algorytmy genetyczne z klasyfikatorem w postaci maszyny wektorów nośnych dla regresji (SVMR) został zastosowany dla zoptymalizowania zestawu danych obejmującego właściwości fizyczne włókien dla prognozowania właściwości wytrzymałościowych przędzy. W tym hybrydowym rozwiązaniu porównano zaproponowany model SVMR z modelem „zaszumionym”, w którym użyto pełny zestaw danych właściwości fizycznych włókien jako danych wejściowych w prognozowaniu. Algorytmy genetyczne w selekcji cech zostały użyte na etapie wstępnego przetwarzania, którego celem było znalezienie i wybranie najlepszych zmiennych, które najefektywniej są powiązane z przewidywaniem wytrzymałości przędzy. Hybrydowe rozwiązanie wykazało lepsze efekty przewidywania wytrzymałości przędzy w porównaniu z modelem „zaszumionym”. Jednakże wyniki badań wykazały, że do realizacji zadania polegającego na wyborze cech z selekcji najkorzystniejszych właściwości włókien bardzo przydatne są również algorytmy genetyczne, które umożliwiają uzyskanie wysokiej dokładności prognozowania wytrzymałości przędzy.

7

Control of Voltage Source Inverter with an LCL Filter without Voltage Sensors

Wang H., Yu C., Zhang J., Cai X.

Przegląd Elektrotechniczny

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2012

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R. 88, nr 5b

119-122

EN

The voltage source inverter with LCL filter has to adopt damping method to suppress the resonance of LCL filter, which increases of losses and sensors. With virtual flux estimation idea, grid voltage-sensor-less technology is applied to design observers for the grid voltage, capacitor voltage and current. The observed grid voltage and capacitor voltage is used to realize voltage orientation control and grid current compensation for unit power factor. The observed capacitor current was fed forward to restrain LCL response and keep the control stable. The simulation results verify the correctness of observes design and the control method.

PL

W artykule analizuje się przekształtnik o źródle napięciowym VSI z filtrem LCL w zastosowaniu do sieci elektrowni wiatrowych. Analizę przeprowadza się na podstawie monitorowania napięcia sieci, prądu sieci i napięcia na kondensatorze.

8

Ultrafast all-optical switch in Bragg-spaced quantum well contained uniform quantum dots

Yu C, Wang T

Optica Applicata

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2012

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Vol. 42, nr 4

821--828

EN

All-optical switching in Bragg-spaced quantum well contained uniform quantum dots (QDs) is investigated in theory. With our design, it is nonresonant excitation for pumping a few meV below the photonic band-gap. The active photonic band-gap structure is shifted by the optical Stark effect, and the circular dichroism and birefringence are induced by the circular polarized pump light. Thus, the optical switching can be realized based on the ultrafast nonlinear effect. The switch, with great advantages of lower requirement of pump light intensity and high contrast ratio, is a promising candidate for the ultrafast all-optical switching devices in future.

9

Study of Self-twist Distribution Functions in Different Convergence Modes

Cui H., Yu C.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 5 (94)

26--29

EN

Twist distribution functions of self-twist yarn are examined by calculating the twist distribution functions of two strands from the nip of self-twist rollers to the convergence point in three different convergence modes. Twist distribution curves of three different convergence modes on the half cycle length are presented by the twist distribution functions. The images show that the self-twist yarn with a phase difference has a lower self-twist peak than inphase self-twist yarn. Thus the existence of a phase difference not only causes a decrease in the self-twist but also a decrease in the length of the weak-twist zone. Furthermore, the value of the phase difference is calculated according to the twist functions of two strands. Compared with the conventional result, that by the method in this paper is closer to the actual length of the zero twist zone.

PL

Funkcje rozkładu skrętu dla przędzy samoskrętnej badano w zależności od punktu łączenia. Funkcje rozkładu zostały przedstawione dla trzech różnych wariantów łączenia. W badaniach analizowano zarówno powstanie przesunięć fazowych jak i okresowych wzrostów wartości skrętu. Na podstawie funkcji rozkładu skrętu dwóch strumieni przędzy można określić przesuniecie fazowe. Stwierdzono, że stosowanie metody identyfikacji opisanej w artykule daje lepsze efekty niż stosowanie metod konwencjonalnych.

10

Bioprocessing of Bamboo Materials

Fu J., Zhang X., Yu C., Guebitz G. M., Cavaco-Paulo A.

Fibres & Textiles in Eastern Europe

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2012

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Vol. 20, no. 1 (90)

13-19

EN

Bamboo culms were processed using microorganisms, and fibre bundles were obtained. Bacteria and fungi with xylanase activity were isolated from the bamboo retting system. Chemical composition analysis of the fibre bundles obtained showed that the components are mainly cellulose, hemicelluloses and lignin. An increase in cellulose and hemicelluloses content was detected along with a decrease in lignin content after bio-processing. Environmental Scanning Electronic Microcopy of the fibre bundles (retted) showed great fibre sensibility towards moisture, which could significantly influence mechanical properties. Our results suggested that the bio-processing presented herein contributes to the possible development of a new means of bamboo bio-processing that can be regarded as a primary process to separate fibre bundles from non-cellulosic tissue in the culm.

PL

Łodygi bambusowe przetwarzano przy użyciu mikroorganizmów, uzyskując wiązki włókien. Bakterie i grzyby o aktywności ksylanazy zostały wyizolowane w systemie roszenia. Analiza chemiczna otrzymanych wiązek włókien wykazała, że głównymi składnikami włókien są: celuloza, hemicelulozy i ligniny. Po biologicznej obróbce stwierdzono wzrost zawartości celulozy i hemiceluloz, a spadek zawartości lignin. Opracowany sposób obróbki łodyg bambusowych wykazał, że jest skuteczny i może być rekomendowany do powszechnego stosowania.

11

A new composite, Co-Sn metal oxide anode for lithium ion batteries

Huang F., Lu X. Z., Zhang Y. F., Luo X. Y., Yu C., Wu R.

Materials Science Poland

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2009

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Vol. 27, No. 1

239--248

EN

The structural and morphological evolution of cobalt-tin (Co-Sn) metal composite oxides, synthesized by the decomposition of CoSn(OH)6 precursor at various temperatures, were investigated by X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). The precursor was also studied by thermal analysis (TG/DTA). The electrochemical performance of nanosized Co-Sn composite metal oxides was investigated to evaluate their suitability for use as anode materials for Li ion batteries. The results revealed that the samples heat-treated at low temperatures consisted of amorphous CoSnO3, and the samples heat-treated at high temperatures comprised crystalline Co2SnO4 and SnO2. The charge capacity and cyclability were sensitive to the structure and composition of the electrode active materials. The samples heat-treated in the phase transition temperature range exhibited relatively worse electrochemical properties.

12

Optimum Water Jets Inclination Angle for Better Tensile Strength in Hydroentanglement Process

Mbwana S. N., Jin X.-y, Chen T., Yu C.

Fibres & Textiles in Eastern Europe

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2009

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Vol. 17, no. 4 (75)

82--86

EN

An experimental set up was developed to evaluate the role of the water jet inclination angle during the hydroentanglement process. Hydroentangled bicomponent nonwoven fabrics were made using the inclined water jet apparatus designed. The effects of water jet inclination angles are discussed and evaluation was made on the basis of the fabric tensile strength. The experimental results revealed that the use of inclined water jets increases the fabric’s tensile strength. An inclination angle of 10 degrees was the optimum, showing higher tensile strength for all nonwoven fabrics tested. These results confirmed that with an optimum water jet inclination angle in the hydroentanglement process, the fabric’s tensile strength can be improved.

PL

Opracowano eksperymentalne stanowisko dla określenia znaczenia kąta nachylenia strumienia wody podczas otrzymywania włóknin. Wytwarzano dwuskładnikowe włókniny stosując strumienie wody o różnym nachyleniu. Przeanalizowano wpływ kąta strumienia i oceniono biorąc jako kryterium wytrzymałość włókniny. Stwierdzono, że kąt nachylenia strumieni wody równy 10 stopni był optymalny ponieważ przy takim kącie uzyskano największe wytrzymałości wszystkich wytwarzanych podczas testu włóknin.