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Isomorphism detection is fundamental to the synthesis and innovative design of kinematic chains (KCs). The detection can be performed accurately by using the similarity of KCs. However, there are very few works on isomorphism detection based on the properties of similar vertices. In this paper, an ameliorated multi-order adjacent vertex assignment sequence (AMAVS) method is proposed to seek out similar vertices and identify the isomorphism of the planar KCs. First, the specific definition of AMAVS is described. Through the calculation of the AMAVS, the adjacent vertex value sequence reflecting the uniqueness of the topology features is established. Based on the value sequence, all possible similar vertices, corresponding relations, and isomorphism discrimination can be realized. By checking the topological graph of KCs with a different number of links, the effectiveness and efficiency of the proposed method are verified. Finally, the method is employed to implement the similar vertices and isomorphism detection of all the 9-link 2-DOF(degree of freedom) planar KCs.

Photovoltaic power generation application with advantages of sustainability and low emission is limited on its low photovoltaic (PV) efficiency mainly due to high panel temperature. In this paper, a solar photovoltaic system coupled by ground heat exchangers (PV-GHEs system) is proposed to reduce the operation temperature of panels and keep a high PV efficiency. Taking Tikanlik with typical arid climate of northwestern China as an example, a numerical model based on the software TRNSYS is built and its reliability are validated based on an actual thermal response test data. The simulation results show that the PV-GHEs system can reduce the panel temperature by 26.8% and increase the annual electricity yield by 7.9%, compared with conventional PV systems. Sensitivity analysis highlights the influences of environmental, geological and design parameters on the system performance. For the long-term operation, a gradually growing ground temperature is unfavorable and may weaken the heat transfer between GHEs and the surrounding ground. For the case of Tikanlik, the growing rate of the ground temperature is 0.67 °C per year and a minimum distance of 10 m between boreholes is recommended when more GHEs are needed. Finally, a life cycle cost analysis of the PV-GHEs system is investigated.

Saturates, aromatics, resin, and C7 asphaltene (SARA) fractions of feedstock were analyzed systematically, and molecular models were constructed. The Monte Carlo method was utilized to investigate the intermolecular interactions between SARA fractions and the ligands absorbed on nickel sulfide nanocatalysts. Additionally, the structural characteristics of the hydrocracked products were analyzed by using elemental analysis, 1H NMR spectroscopy, and FTIR spectroscopy to study the effect of surface modification on the catalytic performances of nickel sulfide nanocatalysts. Simulation results reveal that oleic acid and 1-dodecanethiol have a better miscibility with aromatic fractions of residue than cetyltrimethyl ammonium bromide and that oleic acid has a high affinity and selectivity to C7 asphaltene. Adsorption experiments show that nickel sulfide nanocatalysts modified with oleic acid and 1-dodecanethiol present a certain “core affinity” in the diffusion of residue colloid, which leads to a higher catalyst concentration in C7 asphaltene than the average value in the feedstock. Subsequently, experimental data demonstrate that surface modification with oleic acid and 1-dodecanethiol enhances the catalytic activity of nickel sulfide nanocatalysts, which also facilitates the hydrogenation of C7 asphaltene. Furthermore, nickel sulfide nanocatalysts modified with oleic acid show the best hydrogenation and anticoke activity because of the affinity between oleic acid and C7 asphaltene.

A micro-phase architecture of a fluorinated ethyl cellulose membrane was induced by the fluorinated side chains, which disturbs the crystallinity region of EC. The permeation flux of the fluorinated EC membrane for gasoline desulfurization is substantially improved, with just a slight decrease of the sulfur enrichment factor, which greatly improves the efficiency of pervaporation.