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1
Content available The forward-wave and backward-wave behaviors of electromagnetic waves in two-dimensional photonic crystals
100%
Jiang P. , Yang H. , Xie K.
Optica Applicata
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2014
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tom Vol. 44, nr 1
17--27
EN
The negative refractions are discussed in detail to demonstrate two different two-dimensional photonic crystal structures that undergo negative refractions associated with the backward-wave and forward-wave phenomenon, respectively. The presentation of the left-handed property of effective negative index photonic crystal is followed by a discussion of a backward flowing phase and causality. The forward-wave negative refraction occurs in photonic crystals as a result of anisotropy. This paper is based on the theoretical analysis and is illustrated with the results of finite element method simulations.
2
Content available A new design of a photonic crystal fiber with a beam shaping effect and flexible management of dispersion and confinement loss
100%
Huang Y. , Jiang P. , Yang H. , Yu M.
Optica Applicata
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2014
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tom Vol. 44, nr 3
375--387
EN
A new design of a guiding-index photonic crystal fiber which possesses a beam shaping effect and flexible control of dispersion has been proposed in this paper. It can shape a Gaussian beam into a circular hollow beam with certain dimension, which can be used in optical communication systems with a Cassegrain antenna to improve transmission efficiency by avoiding the loss of energy caused by the subreflector center reflection. In addition, its dispersion and confinement loss can be changed in a broad range by slightly adjusting structural parameters under condition that the hollow beam dimension remains about the same. Fairly practical properties, zero dispersion or flattened dispersion, can be obtained when structural parameters are set appropriately. A series of models with different parameters are analyzed and compared. Results of numerical simulation show that the ultra-low dispersion of 1.802 ps/km/nm can be obtained when λ = 1.31 μm. Several modest design parameters are given as well.
3
Content available Research on a square Cassegrain-type solar concentrating reflector with a double pyramid
88%
Zhang Y. , Yang H. , Jiang P. , Mao S. , Yu M.
Optica Applicata
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2016
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tom Vol. 46, nr 3
461--471
EN
A structure of a solar concentrating reflector is designed in this paper to improve the usage of solar energy. For the dark image which is the result of the secondary mirror in the new type of the Cassegrain solar concentrating system, a double pyramid system is used to improve this phenomenon. By eliminating the dark image, the system enhanced the concentration ratio and the working efficiency. Meanwhile, both the primary and secondary mirrors are shaped into a square section in order to get a better match with a square photovoltaic receiver. While the length of the primary mirror is 89m and the block ratio is 20%, the concentration ratio is equal to 118.86.
4
Content available remote Performance of water-soluble composite sulfate sand core for magnesium alloy castings
88%
Jiang P. , Liu F. , Fan Z. , Jiang W. , Liu X.
Archives of Civil and Mechanical Engineering
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2016
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tom Vol. 16, no. 3
494--502
EN
A novel water-soluble sand core hardened by twice microwave heating was fabricated using composite solution of magnesium sulfate and sodium sulfate as a binder. The tensile strength, water absorption rate, gas evolution and water-soluble rate of the water-soluble composite sulfate sand core (WCSSC) were studied. The micro-morphology of WCSSC was observed by scanning electron microscope (SEM). The results show that tensile strength of WCSSC is 1.2 MPa, and the 4 h storage tensile strength exceeds 1 MPa, and also the water-soluble rate is about 42.65 kg/(min m2), which indicates that WCSSC possesses good moisture resistance and water-soluble collapsibility. The microscopic analysis demonstrates that there are some micro-cracks or holes in the bonding bridge that decreases the strength of WCSSC after being put in humidistat for several hours.
5
Nest composition adjustments by Chinese Bulbuls Pycnonotus sinensis in an urbanized landscape of Hangzhou (E China)
88%
Wang Y. , Chen S. , Blair R. B. , Jiang P. , Ding P.
Acta Ornithologica
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2009
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tom 44
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nr 2
EN
Urbanization changes the abundance and type of resources upon which birds depend, including the type and availability of nesting materials. Although more and more bird species worldwide are colonizing and adapting to urban environments, the ecological processes underlying the responses to urbanization and the relevant resource changes remain unclear. Here we examined the responses of the Chinese Bulbul Pycnonotus sinensis to urbanization by assessing nest composition and available nesting materials at five land-use categories (mountains, farmlands, riparians, urban parks, strips of street trees) of intensifying development in Hangzhou, China. In each land-use category, we classified used and available nesting materials as anthropogenic (e.g. plastics, paper pieces, cloth pieces, nylon particles, threads) or natural materials (e.g. plant culms, roots, leaves). We found that the proportion of anthropogenic nesting materials used by Chinese Bulbuls differed significantly across land-use categories, and it increased significantly with urbanization. Additionally, the increasing amount of anthropogenic nesting materials with urbanization can be attributed to an increase in the availability of anthropogenic nesting materials toward the urban core. Our results indicate that Chinese Bulbuls can adjust the composition of their nests in response to urbanization.
PL
Badając rodzaj materiału gniazdowego używanego przez bilbila testowano hipotezę, że wraz ze wzrostem urbanizacji obserwuje się zmiany w dostępności i użytkowaniu zasobów. Na terenie miasta Hangzhou (wsch. Chiny) wybrano pięć powierzchni różniących się stopniem naturalności, na których wyszukiwano gniazda bilbila. Obejmowały one tereny: górski, rolniczy nadrzeczny, oraz parki miejskie i zieleń wzdłuż ulic (Fig. 1). Obszary te różniły się miarami antropopresji (Tab. 1). W gniazdach szacowano udział materiałów pochodzenia naturalnego i antropogenicznego (plastiki, kawałki papieru, materiału, sznurka itd.), jak również dostępność tych materiałów na badanych terenach. Stwierdzono, że udział materiałów antropogenicznych w gniazdach jak i ich dostępność różni się między badanymi terenami i wzrasta wraz z urbanizacją terenu (Tab. 2, Fig. 2,3). Im więcej tych materiałów było dostępnych, tym więcej znajdowało się w gniazdach (Fig. 4).
6
Content available Theoretical analysis of a hollow laser beam transmitting in an off-axis Cassegrain optical antenna system
75%
Mi C. , Jiang P. , Yang H. , Ke S. , Li B. , Liu J.
Optica Applicata
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2014
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tom Vol. 44, nr 3
421--431
EN
The optical model of a Cassegrain optical antenna with a confocal double-parabolic reflector structure has been designed, and the propagation characteristics of a hollow laser beam, which could avoid the loss of energy caused by the subreflector center reflection in the optical antenna, has been researched in this paper. By detailed analysis and numerical calculations of a receiving Cassegrain antenna with different deflection angles, the coupling efficiency curve and 3-D distributions of the receiving light intensity for different inclined angles have been obtained.
7
A case of human thelaziasis and review of Chinese cases
75%
Liu S. N. , Xu F. F. , Chen W. Q. , Jiang P. , Cui J. , Wang Z. Q. , Zhang X.
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nr 3
8
Effects of exogenous NO on the growth, mineral nutrient content, antioxidant system, and ATPase activities of Trifoliumrepens L. plants under cadmium stress
75%
Liu S.-L. , Yang R.-J. , Ma M.-D. , Dan F. , Zhao Y. , Jiang P. , Wang M.-H.
Acta Physiologiae Plantarum
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2015
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tom 37
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nr 01
EN
This work investigated the effects of SNP (sodium nitroprusside; an NO donor) on 100 lM cadmium (Cd) toxicity in 2-week-old Trifolium repens L. plants. Cd accumulated to a greater degree in roots than in shoots and resulted in oxidative stress, as evidenced by increased concentrations of hydrogen peroxide and malondialdehyde. In addition, Cd exposure markedly hindered root and shoot elongation and biomass production, reduced the activities of H⁺-ATPase in the plasma membranes (Pms) and tonoplasts (V), and inhibited the absorption of mineral nutrition. However, the addition of various SNP doses alleviated the inhibitory effects on plant growth caused by Cd, elevated the activity of the PM H⁺-ATPase in both shoots and roots, enhanced the activity of V-H⁺-ATPase in roots, and partially enhanced the uptake of minerals (shoots: Mg and Cu; roots: Ca, Mg, and Fe) in Cd-treated plants. Shoot and root Cd accumulation significantly diminished when plants were subjected to Cd plus SNP treatments, though the level of root Cd accumulation was not dependent on the SNP dosage level. Moreover, the addition of SNP considerably upregulated ascorbate peroxidases (APX), catalases and superoxide dismutase (SOD) activity in shoots under Cd stress, but downregulated APX and SOD activity in roots. The addition of SNP did not influence glutathione reductase (GR) activity in roots, but markedly increased its activity in shoots. Similar to root GR levels, shoot ascorbate content experienced no significant change between Cd plus SNP treatment and Cd treatment alone; however, root ascorbate and glutathione levels decreased in plant tissues in the treatments with Cd and SNP. The results obtained in this work indicate that SNP applied exogenously, particularly at lower doses, can effectively deplete the detrimental effects on white clover growth, likely by reducing oxidative damage, modulating mineral absorption, and re-establishing the levels of ATPases.
9
Content available Tests and analyses on mechanical characteristics of dwarf-dense-early major cotton variety stalks
63%
Liang R. , Chen X. , Zhang B. , Peng X. , Meng H. , Jiang P. , Li J. , Zhou P. , Kan Z.
International Agrophysics
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2020
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tom 34
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nr 3
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