‎The adjacency matrix is important invariant of a graph with a chemical meaning‎, ‎when we study the chemical graphs‎. ‎In this paper‎, ‎the general form of the adjacency matrices of some hexagonal systems will be determined‎.

This study was conducted during summer and winter of 2018- 2019 in the agricultural research field of Shahid Chamran University. Experimental design was split- plot based on RCBD with three replications. The main plot was the type of agricultural system in three levels including conventional (Conv), organic (Org) and sustainable (Sust) (integrated between Conv and Org) and sup- plot was the type of pre- cultivated crop in sequence with wheat including cultivation of mung bean (M- W), corn (C- W), sesame (S- W) and fallow (F- W). Yield quantity (yield and its component) and quality (grain protein), an estimate of photosynthesis matter transfer index of wheat and soil organic carbon (SOC) after one double-cropping were measured. The result showed that the highest (545.04 g/m2) and the lowest (409.28 g/m2) seed yields were obtained in Conv and Org respectively. In contract, with the changing type of system from Conv to Org, grain protein was increased significantly (from 8.3 to 9.6 %). In addition, the highest (535.47 g/m2) yield of wheat was obtained from M- W double cropping. On the other hands the highest remobilization and current photosynthesis matter were obtained in the organic agricultural system with M- W and conventional with M- W double cropping. The situation of SOC showed that the highest (33.18 mg/g) SOC was obtained in the organic agricultural system with C- W double cropping. The reason for improving SOC in the organic and sustainable agricultural system was application of organic matter (compost and vermicompost) and crop residue management. Totally, from the crop ecology point of view, sustainable agricultural method with a sequence of M- W was the most desirable system.

The first geometric-arithmetic index was introduced in the chemical theory as the summation of 2Ödu dv / (du + dv) overall edges of the graph, where du stand for the degree of the vertex u. In this paper we give the expressions for computing the first geometric-arithmetic index of hexagonal systems and phenylenes and present new method for describing hexagonal system by corresponding a simple graph to each hexagonal system.

The Padmakar-Ivan (PI) index is a Wiener-Szeged-like topological index which reflects certain structural features of organic molecules. The PI index of a graph G is the sum of all edges uv of G of the number of edges which are not equidistant from the vertices u and v. In this paper we obtain the second and third extremals of catacondensed hexagonal systems with respect to the PI index.

Gutman et al. gave some relations for computing the Hosoya indices of two special benzenoid systems R_n and P_n. In this paper, we compute the Hosoya index and Merrifield-Simmons index of R_n and P_n by means of introducing four vectors for each benzenoid system and index. As a result, we compute the Hosoya index and the Merrifield-Simmons index of R_n and P_n by means of a product of a certain matrix of degree n and a certain vector.

In recent years, there has been a growing interest in the use of plasmonic nanoparticles as sources of heat remotely controlled by light, giving rise to the field of thermoplasmonics. To this end, gold nanoframes are unique nanomaterials with the intrinsic capability to generate a nanoscale confined light-triggered thermal effect. Therefore, the plasmonic and thermoplasmonic properties of the gold hexagonal nanoframes have been investigated in this paper. Moreover, the effect of some influential parameters such as gap distance between the two nanoparticles and the distance between the center of the cavities and the center of the nanoframes on the local electric field and the surface temperature of the nanoframes have been reported

In this study the possibility of using fuzzy inference system efficiency, creating a bridge between meteorological, plant parameters, and Daily Yield, and comparing the accuracy of Daily Yield using these systems were investigated. After analyzing the different models and different combinations of daily meteorological data, seven models for estimating daily Yield were presented. For these models, the calculated Yield from AQUACROP model was considered as a base and the efficiency of other models was evluated using statistical methods such as root mean squared error, error of the mean deviation, coefficient of determination, Jacovides (t) and Sabbagh et al. (R2/t) criteria. An experiment was carried out during the 2014-2015 growing season in the Agricultural Research and Education Center of Khorasane Razavi province using a randomized complete block design with a split plot arrangement and four replications. This experiment was including of three irrigation levels treatments as the main plot and three method of planting treatments (transplanting 20-days, transplanting 30-days and direct seeded) as subplots. From the available data, 75 percent was used for training the model and the rest of 25 percent was utilized for the testing purposes. The results derived from the fuzzy models with different input parameters as compared with AQUACROP model showed that fuzzy systems were very well able to estimate the daily Yield. Fuzzy model so that the highest correlation with the 9 input variables (r=0. 98) had in mind and evaluate other parameters, the model with 2 parameters, match very well with the AQUACROP model had stage training. In the test phase, training phase was very similar results and the model with the second phase of harvest index and canopy cover will get the best match. According to the results of this study it can be concluded that fuzzy model approach is an appropriate method to estimate the daily yield.

Abstract:In this paper, a tunable absorber structure based on a graphene hexagonal array in the terahertz range is investigated. The graphene hexagonal absorber is simulated by the finite element method. The effects of the geometry, graphene Fermi energy level and incident light angle, and light polarization on the absorptance of the structure are investigated. The results show that the absorptance spectrum of the proposed absorber is tuned from 6.1 THz to 9.1 THz when the Fermi energy increases from 0.4eV to 0.9eV. The absorptance peak shifts to lower and higher frequencies with increasing hexagonal side length and Fermi energy level, respectively. The absorption of the structure is over 90% in the incident light angle range from 0 to 80º for the TE polarization and in the range of 0-40º for the TM polarization. Also, results indicate that the absorption peaks shift to the lower energies with increasing the dielectric constant of the dielectric layer.

A topological index of a molecule graph G is a real number which is invariant under graph isomorphism. The Wiener and Szeged indices are two important distance based topological indices applicable in nanoscience. In this paper, these topological indices is computed for hexagonal cored dendrimers.