Search

Configuration design is a process of composing customized product from a set of predefined component types with a set of well-defined rules which decide how items can be selected and combined. The configuration solving process is to instantiate all component types into instances. However, the configurator faces the problem of how to determine the instantiation order of component types in the configuration solving process. An unreasonable instantiation order may reduce the accuracy of the configuration result and extend the time required to finish the configuration. In response to the above problem, a heuristic configuration solving process planning method by imitating the crystal crystallization process (CCP) was proposed. According to the product configuration rules, the frequent itemset mining algorithm was used to mine the correlation between the attribute parameters of the product configuration unit. By imitating the CCP and utilizing the calculated coupling strength, the configurator will determine a suitable instantiation sequence for component types. This method has been applied in the GB10 elevator produced by Canny Elevator. It is found that the configuration accuracy has been improved and the consumption of time has been reduced.

The inevitable defects on the surface of the perovskite layer seriously reduce the efficiency and stability of perovskite solar cells. In this work, thymine, one of the four nucleobases in DNA, is ...

A simple and reliable method of preparing high-quality perovskite layers is essential for the high photovoltaic performance of perovskite solar cells. Here, a new low-boiling-point solvent system composed of methylamine solution in ethanol and tetrahydrofuran is designed for methylammonium lead iodide precursor solutions. Concentrated methylammonium lead iodide precursor solutions with a concentration of 2.1 M are obtained, and smooth and compact methylammonium lead iodide films with an area of up to 600 cm2 are prepared directly by one-step spin-coating or blade-coating the precursor solution at room temperature. The rapid evaporation of the solvent and strong interaction between methylamine and methylammonium lead iodide lead to a high crystal nucleus density and intermediate-free crystallization path, and consequently result in a compact and smooth film. The high-quality methylammonium lead iodide films show excellent photovoltaic performance in conventional mesoporous solar cells with efficiencies of 20.0% (0.1 cm2) and 15.6% (10 cm2). Because of the low cost and ease of operation, the solvent system developed in this work is promising both in the laboratory and for future industrialization.

Thermal effect becomes more prominent in the laser gain medium, to overcome this problem, the forced convective heat transfer with reliability and durability is widely used. The hydro-structures of dimensions of the flow channel affect the thermal performance immediately and efficiently. In this paper, with proposed cooling configuration based on longitudinal forced convective heat transfer, the factors of flow rate, state of flow field and surface roughness are investigated. The results reveal that fully developed flow state, higher flow rate and rougher surface lead to a better cooling capability. In the simulation results with 30 L/min flow rate, the calculated averaged convective heat transfer coefficient is as high as 104 W/m2 ·K, and with slightly fluctuations in fully developed flow period.

The forced convective heat transfer with the advantages of reliability and durability is widely used in cooling the laser gain medium. However, a flow direction induced temperature gradient always appears. In this paper, a novel cooling configuration based on longitudinal forced convective heat transfer is presented. In comparison with two different types of configurations, it shows a more efficient heat transfer and more homogeneous temperature distribution. The investigation of the flow rate reveals that the higher flow rate the better cooling performance. Furthermore, the simulation results with 20 L/min flow rate shows an adequate temperature level and temperature homogeneity which keeps a lower hydrostatic pressure in the flow path.

In recent years,all-solid-state passively Q-switched laser technology gets a rapid progress in obtaining picosecond pulses.Comparing with mode-locked lasers with complicated structure,sensitive and difficult alignment,these Q-switched picosecond lasers show great practical potentials for their characters of low cost,simple structure and easy alignment.These Q-switched lasers can provide picosecond pulses with considerable energy,and with the advantage of adjustable pulse repetition rate.In this paper,two existing passively Q-switched picosecond laser approaches,namely,Cr∶YAG microchip lasers,semiconductor saturable absorber mirror(SESAM) microchip lasers,are discussed accompany with the consideration of further treatment to the latter one by nonlinear optical processing and amplification,which are introduced to get narrower pulse width and higher pulse energy.In two categories,we review remarkable work in this field along with breakthroughs of them.

The laser performance and thermal analysis of Nd:KGW laser continuously pumped by 808 nm and 877 nm are comparatively investigated. Output power of 670 mW and 1587 mW, with nearly TEM00 mode, are achieved respectively at 808 nm pump and 877 nm pump. Meanwhile, a high-power passively Q-switched Nd:KGW/Cr4+:YAG laser pumped at 877 nm is demonstrated. An average output power of 1495 mW is obtained at pump power of 5.22 W while the laser is operating at repetition of 53.17 kHz. We demonstrate that 877 nm diode laser is a more potential pump source for Nd:KGW lasers.