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With the improvement of automation degree of coal mine mechanical and electrical equipments, such as conveyors, crushers, mining motors, inverters, and a large number of non-linear loads, cause large reactive power consumption, power factor of coal mine power grid, power supply quality and stability, and bring greater influence to coal mine safety production and economic benefits. As a new generation of high voltage dynamic reactive power compensator, SVG (Static Var Generator) has fast response and compound functions, such as compensating reactive power, suppressing harmonic and imbalance with FC(Filter Capacitor), which plays a good role in improving the power quality of coal mine. This paper designs the system parameters of SVG in coal mine and introduces its application.

Ultra-high voltage (UHV) power grid is a new transmission and transformation technology, which has the advantages of large transmission capacity, long transmission distance, low line loss, saving land resources and obvious economic benefits. Taking the Zhangbei-xiongan 1000kv AC high voltage power transmission and transformation project as an example, this paper constructs the eco-environmental index system of the UHV transmission and transformation project by using the pressure-state-response model, and constructs a set of 18 indexes eco-environmental index system, it mainly includes three aspects: the eco-environmental pressure index caused by the construction behavior in different construction stages of power transmission and transformation projects, and the eco-environmental state index given by on-the-spot investigation and study of projects, based on the construction unit on the ecological environment impact management response measures given indicators. The index system provides a basis for comprehensive and systematic evaluation of the impact of power transmission and distribution projects on the ecological environment, and finally draws the corresponding project construction evaluation conclusions. In this paper, the eco-environmental impact assessment index system of power transmission and transformation engineering has certain universality, and it has certain reference and guiding significance for the ecological environment evaluation of power transmission and transformation engineering.

This research conducted a thermal compression deformation test on two GH4169 alloy samples with 5.40wt% and 5.21wt% Nb contents respectively, under deformation temperatures ranging from 900°C to 1030°C and the strain rates of 0.04s-1, 0.08s-1. Data from the deformation test were used to study the effects of deformation temperature and strain rate on the microstructure, δ phase morphology, and δ phase evolution of both alloy samples, so as to reveal the structural evolution mechanism. The results show that the long needle-like δ phase in the alloy microstructure with high Nb content undergoes deformation fracture and decomposition fracture during deformation and compression under high temperature, with the fracture decomposition temperature being 990°C. Moreover, microstructures of alloys with low Nb content were dominated by granular δ phases; as the deformation temperature increases or the strain rate decreases, the content of the δ phase gradually decreases, causing the alloy’s dynamic recrystallization grain size and dynamic recrystallization volume fraction to gradually increase from deformation twins at low temperatures to complete recrystallization at high temperatures.

Hydrophobically associating polyacrylamide (HAPAM) is considered to be a promising candidate for polymer flooding because of its excellent apparent viscosifying capability. Compared with partially hydrolyzed polyacrylamide (HPAM), the resistance factor and residual resistance factor caused by HAPAM tend to be higher. However, the effective viscosity of HAPAM is lower than that of conventional polymer at a concentration of 2 000 mg/L. The dynamic retention capacity of HAPAM is about 2.3 times that of HPAM. The oil displacement efficiency of HAPAM is lower than that of conventional polymer at a concentration of 2 000 mg/L in the homogeneous sandpack model. The oil displacement efficiency of HAPAM is higher than that of HPAM only in the heterogeneous model (permeability ratio 2.8). Neither high nor low permeability ratios are good for the oil displacement efficiency of HAPAM.

A series of numerical simulations were conducted to study the seismic response in the mountain tunnel portal section. The seismic damage mechanism, including slope cracking and landslide, rockfalls and collapse, and lining cracking were analyzed based on the seismic damage characteristics of the Longxi tunnel during the 2008 Wenchuan earthquake in China. The results show that slope cracking due to the huge horizontal seismic inertial force which exceeds the strength of slope; landslide is caused by the connected cracks where the oblique component of horizontal seismic inertia force exceeds the shear strength of slope; rockfalls and collapse are caused by the cumulative tensile stress in loose soil and rock which exceed the strength of slope; the transverse lining cracks due to the alternate tensile and compressive action of the seismic load along the axial direction, which makes the lining tensile strain accumulates and exceeds the concrete ultimate strength. As for the longitudinal lining cracking, the transverse seismic load makes the bending moment direction in lining alternates, leading to the strength reduction of concrete. Moreover, the circumferential penetrating rupture zone is caused by the large shear force resulting from the slope sliding, which leads to the stress concentration at vault and when the tensile stress exceeds the concrete tensile strength, the vault begins to crack, and then the cracks extend from the arch shoulder to foot.

In this paper, a comprehensive economic allocation method based on virtual energy theory for microgrid complementary power supply is proposed, which is successfully applied to the multi energy complementary planning and comprehensive economic planning of an island microgrid. In order to evaluate and optimize the microgrid in the planning stage more objectively based on the characteristics of various combinations of renewable micro generation and flexible operation modes, a new method of the micro-grid comprehensive economic configuration and optimization of the distributed generation is proposed based on virtual energy theory. Firstly, the Micro-grid model structure based on the virtual energy theory is given. Secondly, the virtual energy conversion model of different distributed power generations is also studied. The micro-grid pluripotent complementary and comprehensive economic optimization model (PCCEP) based on virtual energy theory are reached too. Combined with a practical example, a PCCEP method of the micro-grid based on the Homer software platform is discussed. The case study indicates that the method can avoid the uncertainty of the decision-making factors and the subjectivity of expert evaluation. It is shown that the new method is a practical solution for microgrid comprehensive economic optimization planning.

GF-6 satellite is a kind of high-resolution satellites launched by China in recent years. Its sensors have the characteristics of multispectrals, wide field of view, high spatial resolution and high frequency imaging. In order to carry out fine identification of forest types, this paper proposes a method to improve data screening efficiency and data availability rate in GF-6 satellite data selection stage. This paper describes the selection process and key technical methods of GF-6 satellite data, and gives a verification program. It has been proved that the program meets the design objectives and can quickly scree out the required fast screening technologies in the face of massive data and large-area business applications, thus increasing the degree of automation and reducing the workload of manual visual selection.

The loess slope stability is influenced by rainfall and other factors. In order to find out the mechanism of loess slope instability, especially the influence of rainfall intensity and slope, the indoor model test was performed to study rainfall-induced loess landslide in Tianshui area, Gansu Province. Slope gradient and rainfall intensity are considered as variables, and their influence on slope stability are analyzed based on monitoring of soil suction and water content, and slope deformation process. The results show that the higher the rainfall intensity, the faster the infiltration rate. The volumetric moisture rate under heavy rainfall is more than 10% under small rainfall intensity. The steeper the slope, the lower the infiltration rate for the slope model. The loess slope is prone to overall sliding from bottom to top under the heavy rainfall, and easily lead to down-top retrogressive landslide under light rain.

Dielectric constants can be used to detect hydrates in permafrost regions. Therefore, this study investigated the relationships between the dielectric constant characteristics of sandstone reservoir hydrate and the hydrate saturation degree through physical simulation experiments, as well as the granularity of the surrounding rock. Methane and tetrahydrofuran (THF) hydrates with quartz sands were prepared, and their dielectric constants were analyzed. With different granularities of quartz sands, the dielectric constants of two different methane hydrate sediments decreased with increasing saturation degrees. At a given saturation degree, the dielectric constant of methane hydrate sediments with small granularity was larger than that with medium granularity, a result attributed to the unreacted water in the larger pores of the latter. In addition, the dielectric constant of methane hydrate sediments was larger than that of THF hydrates, which was also attributed to gas-phase factors and the presence of unreacted water. At a given granularity and saturation, the dielectric constants of both the THF and methane hydrates decreased with increasing saturation degrees. We conclude that at low temperature and under normal pressure, THF hydrates cannot be used as a substitute for methane hydrates in laboratory experiments investigating geophysical phenomena.

Sensors of stress or strain currently used in geotechnical and civil engineering applications have the disadvantage that a large quantity of measuring points would result in large bundles of cables. Based on the principle of resistive strain gauge, a type of smart sensor that supports serial communication over RS-485 is developed for the measurement of strain or stress of foundation piles, which has the benefit of good noise tolerance. All the sensors installed along a pile could share a common cable for power supply and communication, and there is no actual limits to pile length. The installation in the field is simple, convenient and efficient. The sensor has a compact structure with reliable waterproof protection. The internal measurement circuit mainly consists of a Wheatstone bridge excitation module, a signal conditioning module, a microcontroller with ADC, a precision voltage reference, and a RS-485 communication module. A group of sensors were calibrated after being assembled, and the calibration results obtained have shown their functionality and reliability.

Based on the case Nanjing Metro Line 4, the method Principal Component Analysis (PCA) was used to study the influence of ground settlement by shield tunnel construction on different geomorphology units. Correlation analysis and weighted least square method (WLS) were applied for variables selection and to obtain their relationship with settlement. 5-7 principal components could be used to present the initial 19- 21 variables after decreasing the dimensions of data. For the floodplain of Yangtze River, variable parameters that highly linearly dependent on settlement were depth of tunnel, distance between the roof of tunnel and the bottom of soft soil layer, thickness of soft soil, compression modulus of soil that tunnel passed through and speed of the cutter head. For the Qinhuai ancient channel, variable parameters were Poisson's ratio, porosities, moisture content, unit weight, cohesion, internal friction angle, compression modulus of soil that tunnel passed through, advancing speed, earth chamber pressure. For the terrace of Yangtze River, variable parameters were cohesion, porosities, moisture content, Poisson's ratio, compression modulus and unit weight of soil. In addition, for the geomorphology unit with col landform, variable parameters were different. Residuals of regression formula are small, which will have certain reference value in practical engineering.

Aiming at the problem of multiple prisms recognition in a narrow field angle in the application of TPS automatic measurement, a novel prism node is designed and implemented. Based on WSNs, measuring prism and electrically controlled dimming glass are grouped together as a prism node. It can easily switch between the fuzzy or the transparent state, to help TPS search and observe the correct prism automatically. Its feasibility is verified by experiments, which greatly simplifies the complexity of engineering installation and operation.

In order to solve the problem of larger internal resistance of thin-film thermoelectric generator (TEG) in series, which could influence the output power and restrict the application, the in-plane carbon nanotube (CNT) TEG in parallel was ingeniously researched. Utilizing the parameters of output power, conversion and energy efficiencies, the ideal and actual models of TEG in parallel were established, respectively. The thermal conduction insulating layer was taken into account, which could provide the theoretical guidance for the experimental test and engineering applications. The CNT films were prepared by the floating-catalyst chemical vapor deposition (CVD), and the experiment and properties of TEG based on CNT films were investigated. The testing circuits of conventional and gas TEGs were designed, and the output powers of the serial and parallel connecting types were tested and compared. The correctness of theoretical model and numerical analysis was proved to be valid. The novel method could effectively enhance the output power, extend the applied range of TEG in MEMS/NEMS and had a fine prospect.

Wind turbine filter and reactive power compensation devices lead to the harmonic impedance of wind farm is not much larger than that of the utility, so the influence by the wind farm harmonic impedance can not be neglected while assessing the harmonic emission value of wind farm A method based on improved complex linear regression is proposed in this paper for assessing the harmonic emission value of wind farm. The linear regression model is established by using the harmonic current at PCC point as the explanatory variable and the harmonic voltage of the wind farm as the explanatory variable. The utility harmonic impedance is calculated by complex least squares method. For various of the topology of wind farm feeder network, an equivalent method of feeder network is proposed to calculate the wind farm harmonic impedance. Errors are analyzed by using the error marginal effect of the dispersion parameter. Simulation and measured data verify the effectiveness of the proposed method

In this experiment, photocatalysic material ,which is magnetic, photoluminesce and has superior light absorbing mesoporous, was synthesized by sol-gel method with tetrabutyl titanate, zinc acetate, stannic chloride , antimonic chloride and ferric nitrate as precursors, and tri-blocked copolymer F127 as the template.Based on the experiment results, when the annealing temperature is at 550°C, the annealing time is 120min , the doping amount of Zn is 4.0at%. These produced samples were shown to have superior luminescence and UV-vis light absorbance. When the weight of template was set to 1.5g, the obtained photocatalysic materials, indicated that their porous mainly distributed within 1.2nm to 4.7nm and their specific surface areas were larger than 110m2/g, and had excellent absorption properties.

The control rod guide tube (CRGT) is used to protect the rod cluster control assembly (RCCA) from bending while providing guidance for the up and down movement of the RCCA. This ensures that the dropping time of the RCCA meets nuclear safety requirements and stops nuclear reactions within the specified time frame. During the up and down movement of the RCCA, the control rod guide cards (CRGC) may experience axial and vibration wear. If the wear is severe, the CRGC may lose its guiding function, resulting in serious problems such as delayed dropping time. In this paper, a machine vision method is proposed to measure the dimensions of the CRGC. Edge extraction, image rectification, and template matching are used to realize autonomous measurement of the CRGC based on its features. The developed measurement software has been used 5 times in domestic nuclear power plant overhauls and has detected 15 CRGTs that were close to the wear limit. This provided data support for the replacement of the CRGTs and effectively improved the quality of nuclear power operation.

Condenser titanium tubes are easily to generate many defects in nuclear power plants, such as corrosion, damage, and wall thickness thinning. Eddy current technology is the main method of condenser titanium tubes in-service inspection, but manual operation has the problem of low efficiency. This article designed one new titanium tube eddy current inspection system based on automatic push-puller, and successfully applied in the nuclear power plant in China. The results show that this system can realize eddy current inspection in the condenser tubes with push-puller machine.

In recent years, the penetration rate of renewable energy in the power system has increased year by year, and the allocation of energy storage is an important development trend to improve the operation stability of the grid-connected power system containing renewable energy. This paper first analyzes the basic concept and operation principle of energy storage devices, and then explains the costs and benefits of energy storage devices. Finally, the industrial park and energy storage power station are used as practical application scenarios to verify the correctness of the proposed method. The example results show that energy storage should be installed in a place where the system network loss is minimal and the reliability of power supply can be maximized, and the capacity of the energy storage system should match the load capacity of the bus bar of the installation site, so as to achieve the greatest comprehensive benefits.

The problem of large-scale distributed new energy consumption is highlighted under the double carbon target. Based on the existing distributed small hydropower and local hydrological and geographical conditions, the pumping-storage linkage function of distributed small hydropower can be realized through small-scale transformation according to local conditions, which can significantly reduce the construction cost and improve the profitability of the power station. The development of small hydropower to pumped storage can effectively enhance the flexible regulation capacity of the power grid. Based on an analysis of the investment environment, profitability and option characteristics of small hydropower to pumped storage projects, this paper conducts a study on the operational mechanism of hydropower participation in the electricity energy market and auxiliary services market to provide support for small hydropower to pumped storage investments in the new situation.

With the urgent need of reducing building carbon emissions to ease climate change, it is necessary to have energy efficient buildings. An effective way of achieving this mission is adopting natural ventilation, which is commonly achieved by openable windows controlled by building occupants in most cases. In this kind of buildings, therefore, occupant window behaviour becomes significantly important on the building performance. To better understand this behaviour, researchers from both engineering domain and social science domain have contributed, but it seems like that they have different research aims, methods and findings. To promote transdisciplinary collaboration in this area, this study has carried out a thorough review of studies on window behaviour in office buildings. The review work collected 66 relevant studies, and analysed their aims, methods and main findings to figure out the differences between engineering studies and social science studies. The existing studies were mainly coming from renowned academic journals (91%) and academic conferences (9%). The comparison revealed significant differences between the two scientific domains, with some overlapping between them. To obtain deeper understanding on occupant window behaviour, critical discussions on how to better collaborate between these two domains in the future have been provided as well.

Cave dwelling is a characteristic residential building in northern Shaanxi. It is not only a masterpiece created by local residents in accordance with nature and local cases, but also meets the requirements of green ecology and sustainable development. In order to understand the influence of ventilation on the indoor environment of cave dwellings in northern Shaanxi, a representative traditional cave dwelling was selected as the research object. Based on the meteorological data in Yan'an and the actual measurement of indoor and outdoor thermal parameters, the methods of theoretical analysis, field testing and numerical simulation were adopted to study the indoor airflow distribution of cave dwellings under different ventilation methods, the results show that: the cave dwellings in northern Shaanxi have good thermal insulation performance, and the indoor temperature fluctuation is small; the relative humidity in the cave dwelling is relatively high, which is opposite to the trend of temperature change; reducing the humidity is the ventilation of the cave dwelling. The main task; the indoor wind speed is too small to form effective ventilation. Adjusting the size of the skylight can improve the natural ventilation in summer to optimize indoor ventilation. Through optimization analysis, when the size of the skylight is 0.5m*0.5m, the indoor airflow velocity changes between 0 and 0.3m/s, the ventilation efficiency is high, and the ventilation effect is high. Good, there will be no eddy current in the room, which can effectively remove moisture and enhance lighting, which can provide a basis for the opening of ventilation skylights in new local caves. Effectively improve indoor heat and humidity environment.

Variable Refrigerant Volume multi connected air conditioning system is widely used in high-rise and super high-rise buildings because of its convenient control, flexible layout and installation and energy saving. However, for high-rise and super high-rise buildings, the outdoor wind environment has a significant impact on the installation, layout and operation performance of Variable Refrigerant Volume multi connected air conditioning system outdoor units. In this paper, the numerical simulation method is used to study the variation characteristics of inlet and exhaust temperature and speed of outdoor unit under different outdoor wind speed and wind direction in winter when the inclination angle of outdoor unit shutter of Variable Refrigerant Volume multi connected air conditioning system is 0 °, ± 30 °, ± 45 ° and ± 60 ° respectively. The results show that in winter, the air inlet and exhaust outlet should avoid the outdoor wind direction as much as possible. When there is no wind outside or the wind speed is 4m/s, the shutter angle should be maintained between 30 ° and 45 °. When the outdoor wind speed is 2m/s, the shutter angle should be maintained at about 30 °.

In this paper, an experimental method of magneto-optical spin Hall effect of light (MOSHEL) based on thermo-optical control is designed. First, we design and implement a pilot experiment—the SHEL experiment controlled by thermo-optical. According to the experiment, it is concluded that the increase of the temperature of the thermo-optical medium will have an important influence on the corresponding thermo-optical spin Hall effect of light (TOSHEL). Accordingly, we designed a device that controls the SHEL in magneto-optical-thermo-optical (MO-TO) two-dimension that uses the thermo-optical effect to simultaneously control the intrinsic TOSHEL and MOSHEL.

Based on the changing trend of the geometric parameters of the scroll profile of the involute of circle with variable radii, a new type of double scroll teeth profile of scroll compressor composed of involute of circle with variable radii is constructed. The construction process of the baseline is discussed, and the baseline equations are deduced. According to the principle of normal equidistance, the geometric model of variable wall thickness double scroll teeth is established, and the suction volume, tooth thickness, and scroll area of double scroll teeth are compared with those of the double scroll teeth composed of ordinary involute of circle. The results show that: compared with ordinary double scroll teeth with constant thickness, the scroll diameter when two scrolls mesh is reduced and the revolutions of orbiting scroll required in the working process are reduced and it is easy to select better scroll profile through adjusting the changing coefficient of the base circle radius k, which provides a reference for scroll machinery using environment-friendly working fluids.

Apache Spark is an open-source in-memory cluster-computing framework. Spark decomposes an application into numerous tasks and assigns them to computing nodes for higher efficiency. However, in heterogeneous environments, some tasks become stragglers because of poor performance of some computing nodes, data skew, etc. These stragglers can affect cluster performance seriously since a job completes just when the last undertaking completions. To mitigate stragglers, Spark uses speculative execution which recognizes slow tasks and picks the node to run speculative task, but the low accuracy in identification and simple way of backing up will further extend the execution time. Then we develop an improved speculative strategy, DBMTPE (Data-Based Multiple Phases Time Estimation), which selects stragglers by estimating their remaining time and chooses a proper way to run speculative task according to the cause. Experiment results show that DBMTPE can run applications up to 10.5% faster over Spark-Native and save computing resource at the same time.

Recently acoustic signature of dislocation avalanches in HCP materials was found to be long tailed in size and energy, suggesting critical dynamics. Moreover, the intermittent plastic response was found to be generic for micro- and nano-sized systems independently of their crystallographic symmetry. These rather remarkable discoveries are reviewed in this paper in the perspective of the recent studies performed in our group. We discuss the physical origin and the scaling properties of plastic fluctuations and address the nature of their dependence on crystalline symmetry, system size, and disorder content. A particular emphasis is placed on the formation of dislocation structures, and on our ability to temper plastic fluctuations by alloying. We also discuss the “smaller is wilder” size effect that culminates in a paradoxical crack-free brittle behavior of very small, initially dislocation free crystals. We argue that the implied transition between different rheological behaviors is regulated by the ratio of length scales $R=L/l$, where $L$ is the system size and $l$ is the internal length. We link this size effect with size dependence of strength (“smaller is stronger”) and the size-induced switch between different hardening mechanisms. We show that the task of taming the intermittency of plastic flow at ultra-small scales can be accomplished by generating tailored quenched disorder which allows one to control micro- and nano-forming and opens new perspectives in micro-metallurgy and structural engineering of miniature load-carrying elements. These insights were beyond the reach of conventional theoretical approaches that do not explicitly account for the stochastic nature of collective dislocation dynamics.