Alfalfa (Medicago sativa L.) is the most valuable perennial forage grass in northern China. We selected 12 ecological criteria and 4 socioeconomic criteria to calculate the suitability of land for alfalfa cultivation in the Xilingol League of the Inner Mongolia Autonomous Region. We combined ecological suitability assessment with fuzzy analysis to standardize the criteria. We used the analytical hierarchy process to determine the weight of these criteria, and used multi-criterion decision analysis (MCDA) to aggregate the criteria. We then calculated the suitability score for each evaluation unit. The suitability was divided into highly, moderately, and marginally suitable, or unsuitable, using the geoprocessing module of ArcGIS 9.3 according to the FAO land suitability classification. We found that highly suitable areas covered 10,799.84 km 2 , accounting for 5.3% of the total area, and unsuitable areas covered 99,235.87 km 2 , accounting for 48.9% of the total area. Combining the fuzzy analysis method with the theory of ecological suitability and the MCDA method to evaluate the suitability of land for alfalfa cultivation provided insights that can guide decisionmakers and farmers to make more practical and scientific decisions.Additional key words: land suitability; GIS; MCDA; Fuzzy analysis; AHP; Medicago sativa; dry continental steppes.* Corresponding autor: wanghong@bnu.edu.cn Received: 28-06-13. Accepted: 24-03-14.Abbreviations used: AHP (analytical hierarchy process); CR (consistency ratio); DEM (digital elevation model); GIS (geographical information systems); MCDA (multi-criterion decision analysis); TM (thematic mapper).

In this paper, we computed the topological indices of pent-heptagonal nanosheet. Formulas for atom-bond connectivity index, fourth atom-bond connectivity index, Randić connectivity index, sum-connectivity index, first Zagreb index, second Zagreb index, augmented Zagreb index, modified Zagreb index, hyper Zagreb index, geometric-arithmetic index, fifth geometric-arithmetic index, Sanskruti index, forgotten index, and harmonic index of pent-heptagonal nanosheet have been derived.

Valley-dependent propagation of light in an artificial photonic hexagonal lattice, akin to electrons in graphene, is investigated in microwave regime. Both numerical and experimental results show that the valley degeneracy in the photonic graphene is broken when the frequency is away from the Dirac point. The peculiar anisotropic wave transport property due to distinct valleys is analyzed using the equifrequency contours. More interestingly, the valley-dependent self-collimation and beam splitting phenomena are experimentally demonstrated with the armchair and zigzag interfaces, respectively. Our results confirm that there are two inequivalent Dirac points that lead to two distinct valleys in photonic graphene, which could be used to control the flow of light and might be used to carry information in valley polarized beam splitter, collimator or guiding device.

The generation and control of valley pseudospin currents are the core of valleytronics. Here, the photonic analogy for generation and control of valley pseudospin currents using the pseudomagnetic fields induced in strained graphene is investigated in a microwave regime. In photonic graphene with uniaxial distortion, photons in two different valleys experience pseudomagnetic fields with opposite signs, and valley-dependent propagations in bended paths are observed. The external-field-free photonic transportation behavior may be very useful in controlling the flow of light in future valley-polarized devices.

We study the wave transport properties near the Dirac-like point at the Brillouin zone center in two-dimensional dielectric photonic crystals with finite thickness. Both simulations and microwave experiments confirm that the transmittance is nearly inversely proportional to the length (L) of the samples in the propagation direction near the Dirac-like point. This transmittance law comes from the conically shaped dispersion. Since the conical singularity at the Brillouin zone center corresponds to zero refractive index, the field at the Dirac-like point contains a basic component of nearly uniform field. In contrast, the field at the Dirac point in the corner of the hexagonal Brillouin zone contains a basic component of inhomogeneous standing-wave–like field.