Wyniki wyszukiwania - BazTech

1

Analysis and application of mechanical system reliability model based on copula function

An H., Yin H., He F.

Polish Maritime Research

|

2016

|

S 1

187--191

EN

There is complicated correlations in mechanical system. By using the advantages of copula function to solve the related issues, this paper proposes the mechanical system reliability model based on copula function. And makes a detailed research for the serial and parallel mechanical system model and gets their reliability function respectively. Finally, the application research is carried out for serial mechanical system reliability model to prove its validity by example. Using Copula theory to make mechanical system reliability modeling and its expectation, studying the distribution of the random variables (marginal distribution) of the mechanical product’ life and associated structure of variables separately, can reduce the difficulty of multivariate probabilistic modeling and analysis to make the modeling and analysis process more clearly.

2

Improved Photovoltaic Properties Of Dye-Sensitized Solar Cells Using Laser Patterned F-Doped SnO2 Thin Films

An H.-R., An H., Riu D.-H., Ahn H. J.

Archives of Metallurgy and Materials

|

2015

|

Vol. 60, iss. 2B

1241--1245

EN

We modified the surfaces of F-doped SnO2 thin films using laser patterning to improve the photovoltaic properties of dye-sensitized solar cells. To do so, we varied the laser power density and the distance between laser-patterned lines. First, we investigated three power densities. Higher densities led to higher sheet resistances owing to increases in surface roughnesses. The lowest power density increased surface roughness without electrical degradation. Next, we explored three line spacings at a fixed power density. The films with the narrowest spacing exhibited the highest power conversion efficiency (~7.00%), the highest short-circuit photocurrent density (16.28 mA/cm2), and a good fill factor (58.82%).

3

Differential effects of grazing on plant functional traits in the desert grassland

An H., Li G.

Polish Journal of Ecology

|

2014

|

Vol. 62, nr 2

239--251

EN

Plant functional traits are linked with environmental factors, individuals and ecosystem structure and functions as plants respond and adapt to the environment. Here, the whole-plant traits (plant height and plant biomass), leaf morphological (leaf area, leaf dry mass and specific leaf area) and chemical traits (leaf carbon, nitrogen, phosphorus contents, C/N and N/P ratio) of six dominant species (Cynanchum komarovii Al, Euphorbia esula Linn, Glycyrrhiza uralensis Fisch, Lespedeza potaninii Vass, Agropyron mongolicum Keng and Stipa breviflora Griseb) were studied in the desert grassland of China, with a grazing experiment including four grazing intensity (0.00, 0.45, 1.00, 1.50 sheep ha-1). The effect of grazing on leaf morphological traits were significant for the six dominant species, while the effects on whole-plant traits were highly significant for S. breviflora, A. mongolicum, G. uralensis, L. potaninii and C. komarovii. Three of the six species (S. breviflora, A. mongolicum and L. potaninii) decreased in plant height (PH) with increasing grazing intensity, while specific leaf area (SLA) and leaf N (Nmass) showed the opposite trend. The whole-plant traits were significantly positively correlated with leaf dry mass (LM), but significantly negatively correlated with leaf nitrogen and phosphorus contents. The first principal component analysis (PCA) axis corresponding to plant size (PH and PB) and leaf size (LA and LM), while the second axis of PCA to leaf chemical traits (Nmass, P, C and N/P). Variations of plant traits in response to grazing were mainly explained by size trait and chemical traits. The functional traits cannot be the only basis for predicting plant species in response to grazing, and a functional analysis of the trade-off between plant traits is also needed.

4

Preparation, characterization and photocatalytic performances of materials based on CS2-modified titanate nanotubes

An H., Hu X., Zhu B., Song J., Zhao W., Zhang S., Huan W.

Materials Science Poland

|

2013

|

Vol. 31, No. 4

531--542

EN

CS2-modified titanate nanotubes (CS2/TiO2–NTs) are fabricated by reaction of CS2 and Ti–O2Na+ species on titanate nanotubes. Pb2+ ions are coated on the modified nanotubes by ion exchange (Pb/CS2/TiO2–NTs). The products are characterized by means of nitrogen adsorption-desorption isotherms at 77 K (BET method), transmission electron microscopy (TEM), X-ray photoelectron spectrometry (XPS), X-ray diffraction (XRD), atomic absorption spectrometry (AAS), and diffuse reflectance spectroscopy (DRS). The photocatalytic performances of the products are evaluated by monitoring their catalytic activities for degradation of methyl orange under UV light irradiation. The effects of calcination temperature and atmosphere on the photocatalytic performance are investigated. The results reveal that the photocatalytic activities of CS2/TiO2–NTs and Pb/CS2/TiO2–NTs are far higher than that of primary nanotubes, and the optimum calcination temperature is 500 °C under N2 atmosphere. It is also discovered that physically adsorbed Pb2+ ions affect the photocatalytic activity of Pb/CS2/TiO2–NTs obviously. The photocatalytic activity of washed Pb/CS2/TiO2–NTs is higher than that of the unwashed one under the same thermal treatment and reaction conditions.

5

Research on Management Policy and National Real Estate Climate Index in China

An H., Ding Y., Gao X., Li J.

Przegląd Elektrotechniczny

|

2012

|

R. 88, nr 9b

25-28

EN

Using ARIMA time series analysis method, this paper predicts NRECI from May to December 2011. Then detailed analysis is made of the NRECI trend and the major management policies introduced in corresponding periods. The results show that NRECI is closely related with management policy of real estate industry in China. The development trend of the NRECI from May to December 2011 indicates that the authorities should take moderate management measures to keep the stable trend sustained.

PL

W artykule przedstawiono metodę obliczania iprzewidywnia współczynnika NRECI (National Real Estate Climate Index). Do tego celu wykorzystano metodę analizy szeregu ARIMA.

6

Leaf stoichiometric trait and specific leaf area of dominant species in the secondary succession of the Loess Plateau

An H., Shangguan Z.

Polish Journal of Ecology

|

2010

|

Vol. 58, nr 1

103-113

EN

Ecological stoichiometry is the study of the balance of multiple chemical elements in ecological interactions. Terrestrial plants exhibit inter- and intra-specific differences in leaf C:N:P stoichiometry that has been used to study plant competition and succession, nutrient use efficiency, N and P nutrient limitation. However, little is known about leaf C:N ratio, N:P ratio in the Loess Plateau, particularly the pattern of leaf C:N:P stoichiometry during the secondary succession. Thus, leaf stoichiometric traits and specific leaf area (SLA) of dominant species at different secondary successional stages in the Loess Plateau were measured. The study was conducted at the Lianjiabian forest region of the Loess Plateau (35.03[degrees]-36.37[degrees]N and 108.10[degrees]-109.08[degrees]E), Gansu, China. Leaf C:N:P stoichiometry and specific leaf area of 18 dominant species (herb) community stage (Stipa bungeana Trin, Bothriochloa ischaemun (Linn.) Keng, Carex lanceolata Boott, Artemisia sacrorum Ledeb, Pulsatilla chinensis (Bunge) Regel, Potentilla chinensis Ser), shrub community stage (Sophora viciifolia Hance, Hippophae rhamnoides (Linn.), Ostryopsis davidiana Decne, Rubus palmatus Thunb, Rosa xanthina Lindl, Acer ginnala Maxim, Spiraea pubescens Turcz, Ziziphus jujuba var. spinosa), early forest community stage (Populus davidiana Dode, Betula platyphylla Suk, Platycladus orientalis (Linn.) Franco), climax forest community stage (Quercus liaotungensis Koidz)) at four secondary successional stages were determined in the Loess Plateau in early June of 2006. The herb and shrub community stage had higher SLA than that in the early forest community stage and climax forest community stage. The Leaf C, N, C:N ratio and N:P ratio at different secondary successional stages were significantly different (P <0.05), but the leaf P didn't differ. The N:P ratio of herb community stage were significant difference from those of the others stages (shrub community stage, early forest community stage and climax forest community stage), but there were not significant difference among the shrub community stage, early forest community stage and climax forest community stage. N:P ratio shifts of the species were consistent along the successional sere, although the N:P ratio of the different species at a successional stage varied considerably. On community level, the lowest N:P ratio (9.8) was found in herb community stage in the secondary succession, the N:P ratio increased to 12.9 in shrub community stage, declined to 12.4 in early forest community stage, and increased in climax forest community stage (e.g. 12.6 in the Quercus liaotungensis Koidz community). The results suggest that the vegetation productivity of the Loess Plateau was N-limited at each secondary successional stage.