An mechatronics coupling design approach for aerostatic bearing spindles

In this paper, a new design approach for aerostatic bearing spindles (ABS) is firstly proposed which takes into account of the interactions between the mechanical and the servo subsystems, including the integration of electromagnetic effects, static pressure characteristics, servo control and mechanical characteristics. According to the air bearing design principle, the geometry of the spindle rotor is designed. The fluid software is used to analyze the influence of the bearing capacity and stiffness on the stability of the spindle. The simulation shows when the air film thickness is 12 μm, the bearing has good load carrying capacity and rigidity. In addition, the influence of motor harmonics on the spindle shaft modes is considered to avoid the resonance of ABS, and to ensure ABS anti-interference capability, proper inertia of ABS is calculated and analyzed. Finally, ABS has a good follow-up effect on the servo control and machining performance through the experimental prototype. The electromechanical coupling design approach for ABS proposed in this paper, can achieve a peak value better than 0.8 μm (surface size: 9 mm × 9 mm) and a surface roughness better than 8 nm in end face turning experiments

Information gain versus coupling strength in quantum measurements

We investigate the relationship between the information gain and the interaction strength between the quantum system and the measuring device. A strategy is proposed to calculate the information gain of the measuring device as the coupling strength is a variable. For qubit systems, we prove that the information gain increases monotonically with the coupling strength. It is obtained that the information gain of the projective measurement along the x-direction reduces with the increasing of the measurement strength along the z-direction, and a complementarity of information gain in the measurements along those two directions is presented.Comment: 7 pages, 1 figure

A Genetic Algorithm Based Multilevel Association Rules Mining for Big Datasets

Multilevel association rules mining is an important domain to discover interesting relations between data elements with multiple levels abstractions. Most of the existing algorithms toward this issue are based on exhausting search methods such as Apriori, and FP-growth. However, when they are applied in the big data applications, those methods will suffer for extreme computational cost in searching association rules. To expedite multilevel association rules searching and avoid the excessive computation, in this paper, we proposed a novel genetic-based method with three key innovations. First, we use the category tree to describe the multilevel application data sets as the domain knowledge. Then, we put forward a special tree encoding schema based on the category tree to build the heuristic multilevel association mining algorithm. As the last part of our design, we proposed the genetic algorithm based on the tree encoding schema that will greatly reduce the association rule search space. The method is especially useful in mining multilevel association rules in big data related applications. We test the proposed method with some big datasets, and the experimental results demonstrate the effectiveness and efficiency of the proposed method in processing big data. Moreover, our results also manifest that the algorithm is fast convergent with a limited termination threshold

Feasibility analysis of excavation with open full section boring machine for ultra-long distance slant in coal mine

Slant is one of the development ways to guarantee the efficient production of mine. It can realize the continuous main transport of the mine, large mining – excavation – transport equipment can use trackless rubber-tyred vehicles directly reach underground, and without the complex ground disassembly and assembly in the underground large chamber. To meet the demand of 10.0 Mt /a production capacity of Kekegai Coal Mine in Shaanxi province, this paper analyzes the influence factors of mine access development mode and geological and hydrogeological conditions of Kekegai Coal Mine. Four kinds of mine development schemes are put forward. Considering the advantages of external transportation conditions, convenient site management, trackless rubber-tyred vehicle of slant with gentle slope and no need to change equipment, the development scheme of main and auxiliary slant + intake and return air shaft in Kekegai Coal Mine is preliminary determined. Through further reviewed the development status and trend of long-distance inclined shaft drilling and blasting tunneling and mechanical rock breaking tunneling technology in coal mine. The problems of low driving efficiency, excess working procedures and high risk in drilling and blasting method and cantilever roadheader construction in existing slant construction are analyzed. The technical scheme of using full section boring machine to drive super long slant is put forward, and applicability of open-type full section boring machine construction is demonstrated. By comparing and analyzing the advantages and disadvantages of the segment support and bolt-mesh-shotcrete support in slant, the supporting mode of bolt-mesh-shotcrete near working face and adding steel arch in the section with local broken surrounding rock is selected. According to the comprehensive analysis of engineering geology and hydrogeology conditions, environmental conditions, engineering conditions, mine construction technology, equipment performance, mine construction period, investment cost and other factors, the mine design and construction technology and equipment of main and auxiliary slant + inlet and return air shaft in Kekegai Coal Mine are feasible and advanced. It can provide a basis for the selection of the same type of mine development mode and the determination of the construction technology and equipment of ultra-long slant, and lay a foundation for the safe, efficient, green, and intelligent construction and development of coal mine

The classicality and quantumness of a quantum ensemble

In this paper, we investigate the classicality and quantumness of a quantum ensemble. We define a quantity called classicality to characterize how classical a quantum ensemble is. An ensemble of commuting states that can be manipulated classically has a unit classicality, while a general ensemble has a classicality less than 1. We also study how quantum an ensemble is by defining a related quantity called quantumness. We find that the classicality of an ensemble is closely related to how perfectly the ensemble can be cloned, and that the quantumness of an ensemble is essentially responsible for the security of quantum key distribution(QKD) protocols using that ensemble. Furthermore, we show that the quantumness of an ensemble used in a QKD protocol is exactly the attainable lower bound of the error rate in the sifted key.Comment: 5 pages, 1 figur