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1
Content available 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
Content available remote Experimental and numerical study on lateral stability of temporary structures
Liu C., He L., Wu Z., Yuan J.
Archives of Civil and Mechanical Engineering
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2018
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Vol. 18, no. 4
1478--1490
EN
This paper investigates the lateral performance of temporary structures, which consist of slender members and corresponding joints, under both vertical and horizontal loads. The ultimate bearing capacity, failure modes and the strain distribution of members are illustrated. Experimental results indicate that the lateral stability of the temporary structures is weaker than the vertical stability. Diagonal bracings are the main load-bearing members which resist horizontal loads while the horizontal bars are used to keep stress low. Based on the joint mechanical parameters and the probabilistic models of initial geometric imperfection, the stochastic finite element models (SFEMs) using the Monte Carlo method have been established. The models can consider the semi-rigid performances of joints and initial geometric imperfection. The numerical results demonstrate consistency with structural tests data. Moreover, the influences of structural layers and spans are analysed based on the SFEM. Multiple factors, including spans, layers and upper vertical loads, should be considered when the lateral capacity of temporary structures is calculated. A rapid prediction formula of the lateral stability of temporary structure has been obtained.
3
Content available Synthesis and Theoretical Studies of a New Insensitive Explosive, 2’-Methyl-3-nitro-2’H-[1,3’-bi(1,2,4-triazole)]-5,5’-diamine
Luo J., Liu Y., Liu Y., Wang J., Chai T., Yuan J., Chang S., Yu Y., Jing S., Ma H.
Central European Journal of Energetic Materials
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2017
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Vol. 14, no. 2
269--280
EN
A new insensitive energetic material 2’-methyl-3-nitro-2’H-[1,3’-bi(1,2,4-triazole)]-5,5’-diamine (1) was prepared by a three-step synthesis from commercially available chemicals. The energetic title compound was comprehensively characterized by various means, including FT-IR, multinuclear (1H, 13C, 14N) NMR spectroscopy, elemental analysis, HPLC and thermal analysis. The sensitivities of the synthesized material towards various external stimuli (impact, friction) were determined according to the BAM method. The optimized structure and related thermodynamic parameters were obtained at the DFT-B3LYP/6-31+G** theoretical level. The detonation properties of the material were also predicted according to the Kamlet-Jacobs formulae and the Monte-Carlo method. The results show that the density, heat of formation, detonation velocity, detonation pressure, impact sensitivity and purity were 1.83 g/cm3, 369 kJ/mol, 7.52 km/s, 25.4 GPa, 82.3 J and 97.7%, respectively. In addition, the compound was an insensitive high explosive which could meet the requirements of high energetic materials.
4
Content available remote Simplified method for computing reactance in the design of saturated-core superconducting fault current limiter
Jia Y., Hao L., Shi Z., Zhu H., Yuan J.
Przegląd Elektrotechniczny
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2016
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R. 92, nr 4
10--13
EN
Generally, the computation of the steady-state reactance of the SCSFCL employs the nonlinear steel core model with both the DC and AC excitation. Noting the deep saturation region of the B-H curve is nearly a straight line, a simplified method is presented in this paper. The slope of the deep saturation region of the B-H curve is taken as an equivalent permeability for the core. Furthermore, the computation can be simplified as a static-magnetic-field model when ignoring the eddy current effect. The example shows this simplified method meets the engineering requirements.
PL
Obliczenia reaktancji SCSFCL wymaga użycia nieliniowego modelu rdzenia stalowego zarówno dla wzbudzenia stałoprądowego jak i zmiennoprądowego. W artykule przedstawiono uproszczoną metodę obliczania reaktancji zakładając, że w obszarze dużego nasycenia krzywa B-H jest prawie linią prostą. Jako przenikalność rdzenia przyjęto nachylenie krzywej B-H w obszarze głębokiego nasycenia. Ponadto, obliczenia mogą być uproszczone przez pominięcie prądów wirowych i przyjęcie modelu statycznego. Przykład pokazuje, że metoda uproszczona spełnia wymagania inżynierskie.
5
Content available remote Deblending of Simultaneous-source Seismic Data using Fast Iterative Shrinkage-thresholding Algorithm with Firm-thresholding
Qu S., Zhou H., Liu R., Chen Y., Zu S., Yu S., Yuan J., Yang Y.
Acta Geophysica
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2016
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Vol. 64, no. 4
1064--1092
EN
In this paper, an improved algorithm is proposed to separate blended seismic data. We formulate the deblending problem as a regularization problem in both common receiver domain and frequency domain. It is suitable for different kinds of coding methods such as random time delay discussed in this paper. Two basic approximation frames, which are iterative shrinkage-thresholding algorithm (ISTA) and fast iterative shrinkage-thresholding algorithm (FISTA), are compared. We also derive the Lipschitz constant used in approximation frames. In order to achieve a faster convergence and higher accuracy, we propose to use firm-thresholding function as the thresholding function in ISTA and FISTA. Two synthetic blended examples demonstrate that the performances of four kinds of algorithms (ISTA with soft- and firm-thresholding, FISTA with soft- and firm-thresholding) are all effective, and furthermore FISTA with a firm-thresholding operator exhibits the most robust behavior. Finally, we show one numerically blended field data example processed by FISTA with firm-thresholding function.
6
Content available Enzymatic Polishing and Reactive Dyeing of Cotton Fabric in One Bath
Wang P., Hong Y., Ding Y., Cui L., Yuan J., Wang Q., Fan X.
Fibres & Textiles in Eastern Europe
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2015
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Vol. 23, no. 1 (109)
109--113
EN
Cellulase has the ability to remove fuzz-fibres from cellulosic textiles, which endows fabric with a glabrous appearance and soft handle. In this paper, the combined uses of bio-polishing and reactive dyeing in one bath were carried out, aiming at shortening the treatment time and reducing the overall consumption of water and energy as well. The properties of cotton fabrics before and after the combined treatments were investigated, including the colour strength, colour fastnesses and tearing strength. The results indicated that the colour fixing agent of soda had noticeable inhibiting effects on cellulase activity. Meanwhile reactive dyes might react with cellulase proteins under alkaline conditions, resulting in decelerating influences on the dye-fibre covalent reactions. The acceptable one-bath process consisted of bio-polishing and dyeing of cotton in neutral solution, followed by dye fixation under alkaline conditions. Compared to polishing and dyeing in two baths, the one-bath method endowed fabric with a bit lower colour strength.
PL
Celulaza ma zdolność do usuwania włosków zmechacenia z tekstyliów celulozowych, co pozwala na osiągnięcie gładkiej powierzchni o delikatnym chwycie. W pracy badano sumaryczny efekt biopolerowania i reaktywnego barwienia przeprowadzanych w jednej kąpieli. Metoda ta ma na celu skrócenie czasu obróbki i zredukowanie ogólnego zapotrzebowania na wodę i energię. Badano właściwości tkanin bawełnianych przed i po obróbce. Między innymi badano nasycenie kolorem, trwałość koloru i wytrzymałość na rozrywanie. Wyniki wskazują, że soda jako środek utrwalający kolor ma zauważalny wpływ na hamowanie działania celulazy. Porównując metodę równoczesnego polerowania i barwienia z metodą, gdzie obydwie obróbki stosowane są indywidualnie stwierdzono, że w metodzie równoczesnej obróbki uzyskuje się nieco niższe nasycenie koloru.
7
Content available remote The Design of the Overload and Overspeed Detection System based on GPS, CDMA and GIS
Yuan J., Li X.
Przegląd Elektrotechniczny
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2013
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R. 89, nr 1b
85--87
EN
The roads and the bridges have been seriously destroyed by the overload and the overspeed of large trucks, which often brings the fatal and huge security disasters. Although the overload has been controlled in the source and the transport tube has been strengthened, little success has been achieved. Therefore, it is required to develop a detection device which can real-timely detect the cargo capacity and the speed of vehicles. This system should intuitively and accurately monitor the cargo weight and the running speed so as to achieve the trucking information management, which will provide the regulatory basis for the transportation management department. The transport vehicle detection terminal designed in this paper has taken full advantage of the rich functionality of GIS system and adopted the vehicle dynamic detection technologies and the embedded technologies as well as the GPS satellite positioning technologies. At the same time, the CDMA wireless communication network has been also employed to communicate with the monitoring center so as to achieve the real-time monitoring for the transport vehicles. This technology is accurate and reliable, which has the good practical value.
PL
Przeciążenie i nadmierna szybkość wielkich ciężarówek może doprowadzić do uszkodzenia dróg i mostów oraz do poważnych katastrof. Istnieje więc konieczność wprowadzenia systemu detekcji pojemności ładunków i szybkości pojazdów, działający w czasie rzeczywistym. Informacje te muszą być przekazywanego do centrum monitoringu w departamencie zarządzania ruchem. W opracowaniu przedstawiono terminal detekcji zaprojektowany w oparciu o system informacji geograficznej GIS i system pozycjonowania GPS, zaadoptowane do detekcji dynamicznej. Do komunikacji z centrum monitoringu wykorzystuje się sieć bezprzewodową CDMA. Zastosowana technologia jest dokładna i realizowalna, ma duże praktyczne zastosowanie.
8
Content available remote Thermal Analysis of the Heat Exchanger for Power Electronic Device with Higher Power Density
Liang Y., Zhang J., Li M., Guo Y., Yuan J.
Przegląd Elektrotechniczny
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2012
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R. 88, nr 12a
328-332
EN
Liquid cooling system has been used in high power electronic device systems to cool down the temperature of power electronic device. Heat exchanger is an important part of liquid cooling system to transfer the heat generated by power electronic device into air. In this paper, a Streamline-upwind/Petrov-Galerkin (SUPG) stabilized finite element analysis method was proposed to solve the water and air governing formulas including the mass conservation equation, the momentum conservation and the energy conservation equation. Furthermore, the thermal characteristic of a heat exchanger is simulated and the result was compared with an experiment. The comparison shows that this method is effective.
PL
W artykule przedstawiono zagadnienie kontroli systemów chłodzenia w urządzeniach energoelektronicznych. Zaproponowano metodę SUPG (ang. Streamline-Upwind Petrov-Galerkin) do obliczania rozpływu cieczy i powietrza, z uwzględnieniem oszczędności ilości, energii oraz pędu środka chłodzącego. Otrzymane charakterystyki wymiany ciepła zostały przebadane symulacyjnie, a wyniki porównano z badaniami eksperymentalnymi.
9
Content available remote Investigation on membrane-assisted CO2 removal process for oxidative coupling of methane in mini-plant scale
Shankui S., Stünkel S., Godini H. R., Xuan S. N., Wozny G., Yuan J.
Czasopismo Techniczne. Mechanika
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2012
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R. 109, z. 1-M
223--232
EN
In this paper the application and the performance of a membrane unit for preliminarily removing CO2 from the product gas mixture in the Oxidative Coupling of Methane (OCM) process based on a mini-plant scale experimental facility are presented and discussed. The model for the membrane unit is validated via experiments based on the comparison of concentrations and recoveries, respectively, with a brilliant agreement <5% under operating pressure up to 5 and 10 bar. It is found that the C2H4 loss rate could not be reduced less than 5% with the CO2 removal rate of 50% in a given membrane module. Since ethylene (C2H4) is the target product in OCM process, a two-stage membrane system is therefore proposed to enhance the C2H4 recovery. This configuration could further reduce the product loss rate while keeping the same CO2 removal rate as that of the single stage process.
PL
W artykule niniejszym zaprezentowano i omówiono zastosowanie oraz wydajność pojedynczej membrany dla wstępnego usuwania CO2 z mieszaniny gazowej w procesie oksydacyjnego sprzężenia metanu (OCM) w oparciu o skalę mini-aparatury doświadczalnej. Model pojedynczej membrany weryfikowany jest drogą eksperymentów opartych odpowiednio na porównaniu stężeń i odzysków przy bardzo dobrą zgodności <5% i ciśnieniu operacyjnym do 5 i 10 barów. Ustalono, że tempa strat C2H4 nie można ograniczyć o mniej niż 5% przy tempie usuwania CO2 wynoszącym 50% w danym module membrany. Ponieważ docelowym produktem procesu OCM jest etylen (C2H4), zaproponowano dwuetapowy system membranowy, który ma zwiększyć jego odzysk. Konfiguracja taka mogłaby w dalszej perspektywie zmniejszyć tempo strat produktu przy niezmienionym tempie usuwania CO2, właściwym dla procesu jednoetapowego.
10
Content available remote Bicriteria scheduling of minimizing maximum lateness and makespan on a serial-batching machine
He C., Lin Y., Yuan J.
Foundations of Computing and Decision Sciences
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2008
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Vol. 33, No. 4
369-376
EN
This paper studies the bicriteria problem of scheduling n jobs on a serial-batching machine to minimize maximum lateness and makespan simultaneously. A serial-batching machine is a machine that can handle up to b jobs in a batch and jobs in a batch start and complete respectively at the same time and the processing time of a batch is equal to the sum of the processing times of jobs in the batch. When a new batch starts, a constant setup time s occurs. We concentrate on the unbounded model, where 6 > n. We present an O(n2) algorithm for finding all Pareto optimal solutions of this bicriteria scheduling problem.
11
Content available remote An on-line algorithm for the bounded p-batch scheduling with chain precedence constraints and unit processing time
Nong Q., Yuan J.
Foundations of Computing and Decision Sciences
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2006
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Vol. 31, No. 3-4
277-290
EN
We consider the problem of scheduling unit time jobs with release dates on a single machine which can process up to b jobs simultaneously as a batch under on-line setting. There are chain precedence constraints on the jobs. The release dates and the precedence relations of the jobs remain unknown until their arrivals. The scheduling problem involves assigning all the jobs to batches and determining the starting times of the batches in such a way that the maximum completion time of the jobs (makespan) is minimized. In this paper we present an on-line algorithm with a worst-case ratio of radic3 for the problem.
12
Content available Propagation of sound interacting with the ocean floor
Überall H., Arvelo J., Yuan J.
Hydroacoustics
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1999
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Vol. 2
291--296
EN
Observed cases of residual intensities between convergence zones of propagating underwater sound, in the absence of a bottom slope must be explained, and are illustrated here, by the effects of sound penetrating into the ocean floor and returned back into the water column by the presence of an upward-refracting bottom sound speed gradient. It is shown that depending on the geometry and the bottom properties, this mechanism can lead lo quite dramatic examples of inter-convergence zone residuals, providing an interpretation of observed effects of this kind.
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