Research on Energy Transmission Mechanism of the Electro-Hydraulic Servo Pump Control System

The electro-hydraulic servo pump control system (EHSPCS) is a volume control system that uses a permanent magnet synchronous motor (PMSM) with a fixed displacement pump to directly drive and control the hydraulic cylinder. The energy transmission law of the system is very complicated due to the transformation of electrical, mechanical and hydraulic energy as well as other energy fields, and qualitative analysis of the energy transfer efficiency is difficult. Energy transfer analysis of the EHSPCS under different working conditions and loads is proposed in this paper. First, the energy flow transfer mechanism was analyzed, and the mathematical and energy transfer models of the key components of the system were established to explore the energy characteristic state transition rule. Second, a power bond diagram model was built, its state equation and state matrix were deduced, and a system simulation model was built. Finally, combined with the EHSPCS experimental platform, simulation experiments were carried out on the dynamic position following and steady-state position holding conditions of the system, and the variation rules of the power of each energy characteristic state and the system energy transfer efficiency under different loads were obtained. The research results provide a foundation for the study of power matching and energy-saving mechanism of the EHSPCS.

Structural Optimization of Logistics Distribution System Based on Characteristic State Space

In this paper, resource flow variables are extracted from the internal structural features of the logistics distribution process and a new method for optimizing the internal structure of the logistics distribution system by using the characteristic state space is proposed. The characteristic state equation is constructed to represent the input and output resources of each basic logistics activity. The basic logistics activity equation is iterated according to the resource flow, and the implementation of the basic logistics process is visually and quantitatively expressed in the form of the characteristic state matrix. According to the nature of the characteristic state space, the optimization problem of the logistics distribution system is transformed into a critical path-planning problem, the gradient calculation of the objective function is solved, and an improved genetic algorithm is proposed. This accelerates the convergence speed of the algorithm and reduces the running time of the optimization process. Taking a listed logistics distribution enterprise as an example, the optimization algorithm is verified, which proves the advantages of the algorithm and provides a new method and theoretical basis for the analysis and optimization of the logistics distribution system.

The Roof Support Load Analysis for Pre-Driven Recovery Room Parameters Design

Submitted by generalized experience entry longwall into pre- driven recovery room (PDRR) in foreign and Russian mine.Submitted by research characteristic state parameters of the roof at failed entry. Give a classification of roof collapse at the entrance longwall into PDRR.On the example of longwall panel 5а-10-18 mine Raspadskaya reviewed formation process of stress-strain condition in area for PDRR. Has been modeled process of entry longwall into PDRR in the conditions of heavy roof. Determine the expected load on the anchor and standing support, installed in the PDRR. Assessed the load on the longwall shield. When calculating the loads was taken into account the following parameters: width pre-driven recovery room, number of standing support in the PDRR and especially its placement, the rate of entry longwall into PDRR.

IMPACTO ECONÓMICO DO PORTO DE FERROL – SAN CIBRAO: HARMONIZACIÓN DE RESULTADOS AO ANO DE REFERENCIA 2016 E COMPARACIÓN COS PORTOS ESTATAIS

As investigacións iniciadas nos anos 60 que tentan determinar o impactoeconómico dos portos nas economías da súa hinterland fóronse depurando, e asmetodoloxías foron converxendo ata permitir realizar comparacións entre uns portos eoutros. No sistema portuario español leváronse a cabo importantes estudos de impactoeconómico e, entre eles, destaca o do porto de Ferrol-San Cibrao, tanto polo carácterpioneiro como pola diversidade de enfoques, como polas metodoloxías que se utilizaronpara a súa determinación. Neste traballo, considéranse os estudos máis relevantes e, parao caso do porto de Ferrol-San Cibrao, harmonízanse os datos ao ano de referencia 2016 através dos coeficientes deflatores do PIB, e realízase unha análise comparativa conrespecto aos portos estatais de características semellantes.The research initiated in the 60s in an atempt to determine the economicimpact of ports in the economies of their hinterland have been refined, and themethodologies have been converging to allow comparisons between ports.In the Spanish port system, important economic impact studies have been carried out,including the port of Ferrol-San Cibrao, both for its pioneering nature and for the diversityof approaches and methodologies that have been used for its determination. In this paper,the most relevant studies are analyzed, the data are harmonized to the reference year2016 through the deflator coefficients of the GDP, and a comparison is made in relation tothe similar characteristic state ports.

A comparative study of external female genitalia (including the 8 th and 9 th abdominal segments) in the family Megalopodidae and other related families of Chrysomeloidea

The external female genitalia of 29 species belonging to three genera of Megalopodidae and 80 species belonging to 61 genera of another four families in Chrysomeloidea were studied. The external female genitalia within the superfamily Chrysomeloidea can be divided into a cerambycid type and a chrysomelid type. The comparative study of external female genitalia shows Megalopodidae is more closely related to the family Cerambycidae than to the family Chrysomelidae s.l. Among five subfamilies of Cerambycidae we studied, the subfamily Lamiinae is most closely allied to Megalopodidae. An evolutionary path is proposed for the spiculum gastrale in Chrysomeloidea: the characteristic state of the spiculum gastrale without a joint is primary, and that with a joint is secondary. The family Orsodacnidae has probably evolved in isolation from the early chrysomelids, due to their shared external female genitalia (cerambycid type). In the family Chrysomelidae, the structure of external female genitalia and ovipositing behavior show that the subfamily Synetinae is closer to the Camptosomata than the subfamily Eumolpinae. In general, the shape of the terminal ovipositor is palp-like in the Chrysomeloidea. Terminal ovipositors are generally palp-shaped in Chrysomeloidea except for those that are lamellate in the genus Callispa and the subfamily Cassidinae who produce egg-sheaths.