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Desorption of Coalbed Methane is one of the key controls to CBM recovery ratio and production capacity. This paper discusses the impact of engineered measures on CBM overall desorption and production capacity with CBM model of Eclipse numerical simulation software. The simulation results show that: with the extension of hydraulic fracture half-length, overall desorption of coal reservoir increased and CBM production capacity improved, daily gas production, maximum gas production and stable yield time increased correspondingly; in different deployment of spacing and well network, the smaller spacing is beneficial to the overall desorption of coal reservoir, but its production can not keep stability because of the serious decline in the late stage of development, while the larger spacing shows in the opposite way.

Sr₂NaNb₅O₁₅ ceramic powders have been synthesized by sol-gel method, ceramics were sintered via a pressureless sintering method. The effect of calcining temperature on the phase composition and microstructure of ceramic powders were investigated by TG-DSC, XRD and SEM analyses. The influence of sintering temperature on density, microstructure and properties of the ceramics were systematically analyzed. The results showed that the optimal calcining temperature was 1300°C, the average size of ceramic powders was about 3μm. When the sintering temperature was 1300°C, the ceramics showed optimized densification and electrical properties(ρ=4.663 g/cm³, d₃₃=45 pC/N, εr=1126, tan=0.027, Ec=17.91 kV/cm, Pr=6.72 μC/cm², Ps=9.45 μC/cm²)

Community detection in complex network has been an active research area in data mining and machine learning. This paper proposed a community detection method based on multi-objective evolutionary algorithm, named CDMOEA, which tries to find the Pareto front by maximize two objectives, community score and community fitness. Fast and Elitist Multi-objective Genetic Algorithm is used to attained a set of optimal solutions, and then use Modularity function to choose the best one from them. The locus based adjacency representation is used to realize genetic representation, which ensures the effective connections of the nodes in the network during the process of population Initialization and other genetic operator. Uniform crossover is introduced to ensure population’s diversity. We compared it with some popular community detection algorithms in computer generated network and real world networks. Experiment results show that it is more efficient in community detection.

Bolt joint has an important influence on the dynamic characteristic of guide rail. Linear rolling guide is chosen as the research object in this paper. Firstly, the dynamic model of the linear rolling guide joint surface is established and its natural frequency is figured out. Then we use ANSYS to make finite element analysis of guide on whether the bolt joint is considered or not. Finally, the validity of finite element model is verified through modal test. By comparing the results of the two kinds of finite element analysis with the theoretical result, we can conclude that the finite element model considering the bolts joint is closer to the theoretical result. So the bolt joint has a great influence on the dynamic characteristics of linear rolling guide. This paper provides the theoretical guide for the research on the bolt joint.

In order to resolve problem of integration of SAP(super absorbent polymer) and fertilizer, in this paper, controlled-release SAP was applied to research the rule of apparent uptake on the nitrogen, phosphorus and kalium nutrient elements by method of nutrient standardization which can provide for theory basis. The result showed that all different treatments on annual lolium perenne had a positive in absorbing nitrogen elements; between kalium and phosphorus nutrition elements had significant negative correlation, correlation coefficient above-0.90.Treatments of FER and YFISJ greatly improved content of nitrogen, phosphorus nutrition elements in lolium perenne, but also were greatly reduce to kalium element absorption. Meanwhile, treatments of different particle sizes of SAP improved obviously absorption of nitrogen and kalium element, phosphorus element of absorption was inhibited. Compound SAP improve nitrogen element apparent top utilization rate of 197%, improve phosphorus element apparent top utilization rate reaches 183% hydration, but reduces the kalium element absorption topped - 187%. The conclusions show that nutrients standardization method cans effective to compare and analysis with nutrients uptake among different treatments. Homemade controlled-release SAP can dramatically improve part of nutrition utilization.

Weld parameter is an important factor affecting micrographic structure and mechanical properties of weld joints. It was investigated by metallographic experiments and mechanical property experiments for the influence of weld heat input on dissimilar steel weld joint of penstock using B610CF and 16MnR steel in water conservancy and hydropower engineering using shielded metal arc welding method and mixed active gas arc welding method. Metallographic experimental results show that in weld metal with the increase of weld heat input the quantity of bainite decreases and crystalline grain is larger when using the same welding method; but in both B610CF and 16MnR steel heat affected zone, there is no distinct difference in microstructure. Mechanical property experimental results show that in weld metal with the increase of weld heat input the impact toughness decreases when using the same welding method, but in both B610CF and 16MnR heat affected zone, there is less difference in impact toughness; and there is no distinct difference in tensile strength and plasticity of weld joint. So moderate weld heat input is recommended.

Microorganisms to improve oil recovery technology is a comprehensive technology of using beneficial activities and metabolites to enhance oil recovery. The obvious effect of field application and good economic benefits make it be active in the field of oilfield development in the long term. In this paper, through indoor experiments in different concentrations of microorganisms bacteria, different concentrations of nutrient solution and function time, evaluate oil sands de-oiling efficiency. Based on test results, optimize the compound of bacteria that from different sources and find out when the ratio of field and lab bacteria is 1:7, the de-oiling efficiency reach the peak of 86.47%, which further expand the mechanism of microorganisms enhanced oil recovery.

In order to investigate the effect on manufacturing quality of focus position misalignment between laser beam and powder convergence in laser metal deposition shaping (LMDS) processing, several experiments including single-track monolayer, straight thin-wall and ring thin-wall were made. The measurements and analysis on shape, size and surface quality of the experiment parts were carried out. An omnidirectional detecting method to check the misalignment of focus position was brought forward and tested. The results indicate that the misalignment of focus position directly affects the quality of shaping parts and shows the regularity, the detecting method can easily detect the focus position misalignment on random direction and angle and guide the adjustment on them.

A high-precise automatic positioning system for data sample of linear time grating sensor is designed. In order to achieve linear time grating sensor of data sample, improve measure work efficiency, an ARM MCU is used as a major chip to control the stepper motor to rotate. In this way, the stepper motor drives the ball screw, the moving probe of linear time grating sensor and reading head of linear grating to move synchronously. A high-precision automatic positioning of the system hardware is designed. In addition, ARM controlling circuits and stepper motor driving circuits are designed. Therefore, the special communication interface is designed for the high-precision automatic positioning system, receiving the feedback signal from time grating sensor, forming a high-precision closed loop control system, and communicating with upper computer by serial. Experiment results prove that the positioning precision of control system can reach 0.1 um.

Under the action of surface-underground unite mining, Slope stability is related to underground mining location and mining space dimension, This paper studies the underground mining of slope outer region on slope stability influence characteristic; With the increase of mining width stability coefficient increases, when mining width reach a certain value stability coefficient tends to constant; With the increase of mining depth stability coefficient increases, when mining depth reaching a certain value stability coefficient began to decrease; this show that the underground mining has a direct effect on slope stability, its size needs a combination of their relative spatial position relation and mining geometric size to determine.