Wyniki wyszukiwania - BazTech

1

The influence of ship rolling motion on take-off aerodynamic characteristics of aircraft

He Z., Sun X., Gu X.

Polish Maritime Research

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2018

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S 2

23--29

EN

Ship motion is an important factor affecting on the safety of ski-jump take-off. The simplified frigate ship SFS1 was numerically simulated, and the results were compared with the experimental data, the feasibility of the calculation method was verified; Meshless method and WALE turbulence model were used to simulate the process of aircraft skijump take-off, aerodynamic characteristics under different rolling conditions during the aircraft ski-jump take-off process were presented. The results showed that: the influence of ship rolling motion on lift coefficient, drag coefficient and pitching moment was small, side force and rolling moment were greatly affected by rolling motion; the region of downwash with the maximum speed was about 10 m from the bow; the safety of ski-jump take-off was greatly affected when aircraft was close to the bow within 20 m.

2

Mass transfer process of leaching weathered crust elution-deposited rare earth ore with magnesium salts

Chen Z., Zhang Z., He Z., Chi R.

Physicochemical Problems of Mineral Processing

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2018

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Vol. 54, iss. 3

1004--1013

EN

In order to optimize the leaching process of weathered crust elution-deposited rare earth ore with magnesium salts, the influence of different flow rate, concentration of magnesium ions, initial pH of magnesium salts solution and experimental temperature on the mass transfer process of rare earth and aluminum was investigated in the case of using magnesium salts as leaching agent. The relationship between the flow rate μ and the HETP (Height Equivalent of Theoretical Plate) is in accordance with the Van Deemter equation when magnesium salts were used as leaching agent. The optimum condition for rare earth and aluminum were 0.4 cm3/min of flow rate and 0.2 mol/dm3 of magnesium ion concentration of magnesium sulfate, magnesium chloride and magnesium nitrate respectively. Under this condition the mass transfer efficiency of rare earth and aluminum with three kinds of magnesium salts follow the order of Mg(NO3)2>Mg(Cl)2>MgSO4. High temperature contributes to improving the mass transfer efficiency of rare earth and aluminum. Magnesium nitrate as the leaching agent can get the highest leaching mass transfer efficiency of rare earth and magnesium sulfate as the leaching agent can make the impurity leaching and mass transfer efficiency of Al is the lowest.

3

Depth-resolved measurement of the compression displacement fields on the front and rear surfaces of an epoxy sample

Zhang W., Dong B., Zhang W., He Z., Xie S., Zhou Y.

Optica Applicata

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2018

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Vol. 48, nr 2

311--323

EN

Compression is one of the typical parameters measured in material mechanics. In this research, the compression displacement fields on the front and rear surfaces of an epoxy sample are measured by using a tilt depth-resolved wavenumber-scanning Michelson interferometer. The light source is a distributed feedback laser diode, the wavenumber of which can be modulated to about 1.017 × 104 m–1 by the temperature without mode hopping. A random-sampling Fourier transform is designed to evaluate the phase differences before and after the applied loads. Experimental results show that the depth-resolved measurement of the compression displacement field is of high accuracy. It can be used to analyze force propagation inside resin-based composites.

4

Analytical modeling of grinding process in rail profile correction considering grinding pattern

Liu Y. M., Yang T. Y., He Z., Li J. Y.

Archives of Civil and Mechanical Engineering

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2018

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Vol. 18, no. 2

669--678

EN

An analytical introduction to rail grinding was presented in this paper where a newly-designed profile serves as the targeted ground profile to extend the rail's service life. A method for determining eliminated metal due to rail grinding is established as an initial consideration in the process of rail profile correction. The analytical model of material removal contains grinding wheel characteristics such as rotation speed, feeding speed, and applied pressure to the ground rail. The assumed coefficient in this model was fitted by a scratch test between a single abrasive grain and rail specimen. The sectional area s of removed metal can be used to estimate grinding capacity rather than the traditional grinding depth. An algorithm that generates personalized grinding patterns is proposed to arrange grinding wheel location and proper sequence. The whole procedure was indirectly validated in terms of grinding quality and rail profile error through rail grinding field data. A grinding pattern was generated by the proposed method that can effectively simulate the ground rail profile within a pre-determined tolerance. The area difference of predicted and target profiles was 13 mm2 (6.6%) and the experimental result was 12.2 mm2 at rail cross-section.

5

Investigation of low-sidelobe beampattern controlling methods for acoustic transmitting array of underwater vehicles

He Z., Shi Q., Wu S.

Polish Maritime Research

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2017

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S 2

103--110

EN

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.

6

Different Patterns of Changes in Foliar Carbon Isotope Composition Along Altitude

He Z., Zhan S., Wang W., Hu L., Wu S.

Polish Journal of Ecology

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2017

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Vol. 65, nr 2

227--235

EN

Three types of alpine plant species, Carex montis-everestii, Quercus aquifolioides and Stipa capillacea, along an altitudinal gradient of 3005-5025 m on the Tibetan Plateau, were chosen to test the generality of the hypothesis that foliar carbon isotope composition (δ13C) of C3 plants increases significantly with altitude and to determine climate drivers shaping its altitudinal pattern. Temperature and relative humidity showed significantly negative correlations with altitude; however, precipitation and soil water potential remained unchanged with altitude. Foliar δ13C of C. montis-everestii, Q. aquifolioides, S. capillacea alone or combined together did not significantly increase with altitude, which does not support the leading hypothesis of increased foliar δ13C with altitude. There was no difference in foliar δ13C among all three species. Multi-factor correlation analyses showed that temperature, precipitation and relative humidity alone did not affect foliar δ13C of C. montis-everestii and S. capillacea, but conferred significant effects on foliar δ13C of Q. aquifolioides.

7

Mineralogical and chemical characteristics of the lead-zinc tailing and contaminated soil from the mine tailing pond in Hunan Province (China)

Li C., Zeng L., Fu J., Chen J., He J., He Z.

Physicochemical Problems of Mineral Processing

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2017

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Vol. 53, iss. 2

1133--1147

EN

The mineralogical and chemical characteristics of heavy metals in tailings and soils is an imperative for potential ecological risk assessment of metals to environment and heavy metals pollution prevention and control. The lead-zinc tailing and contaminated soil in and near the tailing pond were sampeled from a mine tailing pond in Hunan province (China), in which the chemical composition, phase composition and thermal behavior of tailing and soil were investigated. Furthermore, the petrography of lead-zinc tailing and chemical fractionations of Pb and Zn in the contaminated soil were studied in details. The mineral phases of lead-zinc tailing were galena, pyrite, chalcopyrite, sphalerite, quartz and fluorite, as distinguished by the reflected light microscopy and further proofed by the scanning electron microscope-energy dispersive spectrometer under the back scattered electron mode. Chemical fractionations were carried out by the European Community Bureau of Reference (BCR) sequential extraction procedure for Pb and Zn in the soil and the mild acido-soluble (F1), reducible (F2), oxidizable (F3), and residual (F4) fractions were 5.90, 75.24, 4.90 and 13.96% for Pb, and 47.74, 34.06, 9.59 and 8.61% for Zn, respectively. Subsequently, the individual contamination factor (ICF) of Pb and Zn were calculated as 6.16 and 10.61, respectively. The DTPA-available content of Pb and Zn in the contaminated soil were 39.9 and 170.7 mg·kg-1, respectively. The study provided a base for selecting remediation strategies in the studied area.

8

Effect of gradient temperature rolling (GTR) and cooling on microstructure and properties of E40-grade heavy plate

Gaosheng L., Wei Y., Qingwu C., He Z.

Archives of Civil and Mechanical Engineering

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2017

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Vol. 17, no. 1

121--131

EN

Despite numerous investigations on gradient temperature rolling (GTR) and its influence on grain refining, no research exists on appropriate cooling after GTR, which is important in the microstructural control. This work focuses on the effect of final microstructure on heavy-plate properties and microstructural evolution during different rolling and cooling processes. GTR and uniform temperature rolling (UTR) were applied to E40-grade heavy plates. GTR plates were maintained at 1073 K at their surface and 1473 K at their core. After rolling, experimental plates were cooled at a series of rates. Their microstructure and mechanical properties were studied. The plate prepared using GTR and air cooling had the best integrated property because of its uniform and fine ferrite microstructure. The GTR plate strength increased gradually with a corresponding decrease in toughness as the cooling rate increased. The uniform temperature rolling plate cooled in water exhibited the worst mechanical properties.

9

Electrostatic Hazards Assessment of Nitramine Explosives: Resistivity, Charge Accumulation and Discharge Sensitivity

Peng Q., Cao W., Zhou W., He Z., Jiang W., Chen W.

Central European Journal of Energetic Materials

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2016

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Vol. 13, no. 3

755--769

EN

The electrostatic hazards of nitramine explosives (RDX, HMX) were assessed in this paper. The resistivities of different particle-size RDX and HMX were tested by a device designed and manufactured according to the standard ISO/IEC 80079-20-2:2016. This work shows that the resistivities of uncompacted RDX and HMX increase as the particle size decreases. Charging characteristics test experiments were also carried out using a so-called sieve method. Using this method, the influence of aperture size on charge accumulation of RDX was studied, and the characteristics of electrostatic accumulation of different particle-size RDX and HMX sieved with 50 mesh standard sieve were compared. The results show that the absolute value of the charge accumulation increases as the mesh number increases (i.e. the aperture size decreases), and increases as the particle size is decreased, indicating that nano-sized RDX and nano-sized HMX accumulate static electricity more easily than conventional micron-sized ones. Finally, the electrostatic discharge (ESD) sensitivity of nano-sized RDX and nano-sized HMX was investigated. Nano-sized nitramine explosives were found to have a higher ESD sensitivity than micron-sized ones.

10

New Mixed Weibull Probability Distribution Model for Reliability Evaluation of Paper-oil Insulation

He Z., Wang Y., Li J., Gong S., Grzybowski S.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1a

202--206

EN

This paper presents a new mixed Weibull probability distribution model for reliability evaluation of the paper-oil insulation. The breakdown voltage, furfural, and six other characteristic parameters were chosen to reflect the reliability of paper-oil insulation. The new mixed Weibull probability distribution model was established to evaluate the reliability of the paper-oil insulation. Reliability predictions of the paper-oil insulation at different times verified the feasibility of the new mixed Weibull probability distribution model.

PL

W artykule przedstawiono metodę budowy modelu rozkładu prawdopodobieństwa Weibulla, w wykorzystaniu do oceny niezawodności izolacji papierowo-olejowej. Wykorzystywanych jest osiem parametrów dotyczących niezawodności. Wykonane przewidywanie niezawodności dla różnych odległości czasowych potwierdzają skuteczność metody.

11

A Novel Vibration Monitoring System Based on Wireless Sensor Networks

Du D., He Q., He Z.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 3b

35--37

EN

Considering the application limitations of traditional vibration monitoring system, wireless vibration monitoring system is more needed especially for large-scale complex equipment, many measuring points, and widely distributed equipment of process industrial. According to the characteristic and demand of wireless sensor networks and vibration monitoring system, a new design method of wireless sensor network node used in equipment vibration condition monitoring was proposed. First of all, a miniature low-power sensor node for wireless vibration monitoring of equipment was developed. Then, a wireless vibration monitoring system based on wireless sensor networks was constructed. Finally, the general scheme of the system, the design ideas of node hardware and software, the strategies of wireless networking and communication as well as the monitoring software of the system are described. The results of experiment showed that the data sampled by wireless vibration monitoring node is correct, the communication of network system is accurate, and the whole system is reliable. The system therefore can be widely used in vibration monitoring of various equipment, particularly useful in electric power, metallurgy, petrochemical and other widely distributed equipments.

PL

W artykule zaproponowano metodę tworzenia węzła sieci czujników bezprzewodowych, na potrzeby systemu monitorowania wibracji. Przedstawiony został sposób projektowania oraz schemat finałowego systemu, z opisem strony sprzętowej i programowej. Przedstawione wyniki badań eksperymentalnych potwierdzają skuteczność i poprawność działania.

12

A Multi-parameter Comprehensive Analytical Method for Online Assessing Power Transformer Condition

He Z., Liu Y., Chen J., Bai W., Sheng G., Jiang X.

Przegląd Elektrotechniczny

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2013

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R. 89, nr 1a

219--222

EN

The effective assessment on the operation condition of power transformer is an important means to conduct the condition maintenance for transformer and to improve the reliability of power system. Based on the amount of information of all kinds of online monitoring conditions obtained from the transformer intelligent components, the assessment model for comprehensive condition of transformer is established in this study through the introduction of extension theory. First, with respect to the disadvantage that there is considerable subjectivity in constructing judgment matrix by the traditional analytic hierarchy process (AHP), a new method is adopted to construct the judgment matrix. The orthogonal experimental design method, finite element simulation as well as AHP are adopted to determine the weighting of condition information index with scientific and objective attitude; next, the framework for comprehensive assessment of transformer condition is established with the extension-based comprehensive assessment method to achieve the qualitative and quantitative assessment on the transformer condition. The method is proved to be correct and valid through analysis of examples.

PL

W artykule przedstawiono wyniki badań dotyczących opracowania modelu szacowania warunków pracy transformatora. W pierwszym kroku stworzono metodę budowy macierzy orzeczeń, z uwzględnieniem pewnych subiektywności tradycyjnej metody tworzenia tej macierzy (ang. Analytic Hierarchy Process). Do oszacowania wagi wskaźnika informacji o warunkach pracy, wykorzystano metodę eksperymentalną, symulację elementów skończonych oraz AHP. Wykonane badania wykazały poprawność działania metody.

13

The boundary value problem of higher order differential equations with delay

He Z., Shen J.

Demonstratio Mathematica

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2013

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Vol. 46, nr 1

87--100

EN

In the paper, Guo–Krasnoselskii’s fixed point theorem is adapted to study the existence of positive solutions to a class of boundary value problems for higher order differential equations with delay. The sufficient conditions, which assure that the equation has one positive solution or two positive solutions, are derived. These conclusions generalize some existing ones.

14

Effects of saline-alkaline stress on early growth strategy and colonization success of Flaveria bidentis ( L.) Kuntze (Asteraceae ) - a new exotic plant in Northern China

Chai M., Shi F., He K., Li R., Cao D., He Z.

Polish Journal of Ecology

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2012

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Vol. 60, nr 3

559-565

EN

Flaveria bidentis, an annual grass native to South America, has invaded into many countries all over the world, including South Africa and Egypt in Africa, Britain and France in Europe, Japan in Asia, and Australia. In China, this plant species has been widely distributed in Hebei province since 2001 of its first discovery in Tianjin. In salinized soil of northern China, F. bidentis has formed mono dominant communities owing to its opportunistic characteristics. In this study, we investigated germination rate, germination energy, germination index and vigor index in response to different saline-alkaline stresses. Lengths of seedling, hypocotyl, and radicle were also examined. During germination process, germination rate, germination energy, germination index, and vigor index decreased due to higher salinity and alkalinity (pH). Hypocotyl elongation was stimulated at low salinity and alkalinity, but decreased with increasing salinity and alkalinity. The lengths of radicle and seedling were inhibited sharply with increasing salinity and alkalinity. These results suggest that a reciprocal enhancement between salt stress and alkaline stress was a characteristic feature during seed germination of F. bidentis. Ungerminated seeds resumed to germinate after transferred to distilled water, indicating that seeds remained viable during their exposure to saline-alkaline stresses. Stepwise regression analysis indicated that the effects of salinity, alkalinity (pH), and buffer capacity on seed germination and seedling growth were significantly different in magnitude. Salinity and alkalinity (pH) were the dominant factors in seed germination and seedling growth of F. bidentis respectively. Further, the results of this study suggest that F. bidentis has developed excellent adaptative strategy in its early stage of life cycle which partially explains its current invasion success in northern China.

15

Jeszcze jedna funkcja mikrobiologicznych ogniw paliwowych w oczyszczaniu ścieków: wytwarzanie wody o wysokiej jakości

He Z.

Chemik

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2012

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Vol. 66, nr 1

3-10

PL

Zrównoważona technologia oczyszczania ścieków powinna skutecznie obniżać stężenie zanieczyszczeń, odzyskiwać energię i minimalizować zrzut cieczy. Potencjalnym kandydatem na taką technologię jest mikrobiologiczne ogniwo paliwowe (MFC - ang. Microbial Fuel Cell), które może wytwarzać bioelektryczność bezpośrednio z oczyszczania ścieków. Jednak oczyszczony ściek z MFC nie jest ponownie wykorzystywany z powodu niezadowalającej jakości wody. Do wytwarzania wody o wysokiej jakości za pomocą MFC zaproponowaliśmy i zbadaliśmy dwie metody wykorzystujące zintegrowane technologie membranowe. W szczególności osmotyczne MFC, w których wykorzystuje się osmozę wymuszoną (ang. forward osmosis) i MFC, okazały się wykonalne w badaniach na skalę laboratoryjną. Nowa funkcja polegająca na wytwarzaniu wody o wysokiej jakości, choć nadal stanowiąca duże wyzwanie, czyni z MFC obiecującą metodę ekologicznie zrównoważonego oczyszczania ścieków.

EN

A sustainable wastewater treatment technology should effectively reduce contaminant concentration, recovery energy contents and minimize liquid discharge. A potential candidate for such a technology is a microbial fuel cell (MFC) that can produce bioelectricity directly from wastewater treatment. However, the treated effluent from MFCs is not reused because of unsatisfied water quality. To produce high-quality water using MFCs, we proposed and studied two approaches with integrated membrane technologies. Especially, the osmotic MFCs that take advantage of both forward osmosis and MFCs have been proven feasible with bench-scale studies. The new function of producing high-quality water, although still very challengeable, will make MFCs a promising approach for sustainable wastewater treatment.

16

A velocity measurement method based on scaling parameter estimation of chaotic system

Liu L., Hu J., He Z., Han C., Li H., Li J.

Metrology and Measurement Systems

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2011

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Vol. 18, nr 2

275-281

EN

In this paper, we propose a new method of measuring the target velocity by estimating the scaling parameter of a chaos-generating system. First, we derive the relation between the target velocity and the scaling parameter of the chaos-generating system. Then a new method for scaling parameter estimation of the chaotic system is proposed by exploiting the chaotic synchronization property. Finally, numerical simulations show the effectiveness of the proposed method in target velocity measurement.

17

Positive periodic solutions for second order impulsive differential equations

Shen J., Wang W., He Z.

Demonstratio Mathematica

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2011

|

Vol. 44, nr 2

297-316

EN

The existence of positive periodic solutions for a class of second order impulsive differential equations is studied. By using fixed point theorem in cone, new existence results of positive periodic solutions are obtained without assuming the existence of positive periodic solutions of the corresponding continuous equation.

18

Synthesis of HMX via Nitrolysis of DPT Catalyzed by Acidic Ionic Liquids

He Z., Luo J., Lu Ch., Xu R., Li J.

Central European Journal of Energetic Materials

|

2011

|

Vol. 8, nr 2

83-91

EN

The direct nitrolysis of DPT to synthesize HMX with ionic liquids (ILs) as catalysts was investigated. The results showed that [Et3NH] HSO4 was the best catalyst among 18 ILs used and the yield of HMX was up to 61% against 45% without IL. The ILs could be effciently recovered by simple distillation and extraction after reaction without any apparent loss of catalytic activity even after 10 times recycling.

19

Effect of hadronic rescattering on the elliptic flow after the hydrodynamics model

Ma G., Ma Y., Sa B., Cai X., He Z., Huang H., Long J., Shen W., Zhong Ch., Chen J., Zuo J., Zhang S., Shi X.

Nukleonika

|

2006

|

Vol. 51,suppl.3

21-27

EN

Abstract A hydrodynamics + hadronic rescattering model is used to simulate Au+Au collisions at 200 GeV and a Cooper-Frye method is adopted for hadronization. The effect of hadronic rescattering on elliptic flow V2 in 20 40% Au+Au collisions at 200 GeV has been investigated. It is found that the hadronic rescattering can suppress elliptic flow V2 and makes an asymmetric system in momentum space tend to be less anisotropic. The suppression effect becomes weak with increasing transverse momentum. In addition, the effect of hadronic rescattering on transverse momentum spectra and anisotropy of hadronic coordinate space is presented.

20

Solving point-feature labeling placement problem by parallel Hopfield neural network on GPU graphics card

He Z., Harada K.

Machine Graphics and Vision

|

2006

|

Vol. 15, No. 1

99-120

EN

This paper discusses the application of parallel Hopfield neural networks in solving the point-feature labeling placement (PFLP) problem by using programmable graphics hardware found in a commodity PC. In this paper, we focus on two aspects. The first aspect concerns mapping the PFLP onto parallel Hopfield neural network. The second aspect is the detailed method of implementing the parallel Hopfield neural network on graphics hardware. We demonstrate the effectiveness of implementing the parallel Hopfield network by solving the PFLP problem. Moreover, our proposal makes use of the advantages of the parallel Hopfield network on low-cost platforms.