North China University of Water Conservancy and Electric Power

www.ncwu.edu.cn
Zhengzhou, China

North China University of Water Conservancy and Electric Power is a teaching and research university established in 1951 and is now located in Zhengzhou, Henan Province. Co-sponsored by the province and the Ministry of Water Resources, NCWU is a full-time public university specializing in the field of water resources and hydropower, with engineering as a key program, multidisciplinary subjects developing constantly and coordinately, ranging from science, agriculture, economics, management, art to law. NCWU is ranked as “Excellent” in the Evaluation on Undergraduate Teaching Level conducted by the Ministry of Education, which is also the backbone university enjoying priority support from Henan Province. NCWU mainly recruits full-time undergraduate and graduate students together with a small number of three-year diploma students. Wikipedia.

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Zhang B.,North China University of Water Conservancy and Electric Power
Philosophical Magazine Letters | Year: 2017

The magnetic, mechanical and thermodynamic properties of LaMO3 (M = Ti~Fe) have been systematically investigated using the first-principles calculations. The total magnetic moments of LaMO3 are mainly from the M atom, and the contributions from La and O are very small. For LaTiO3, LaVO3, LaCrO3 and LaMnO3 the total magnetic moments agree well with experiment, while with somewhat larger disagreement for LaFeO3. Using the GGA + U (U = 5.6 eV), the calculated magnetic moment of LaFeO3 is 4.98μB, which is in agreement with experiment data. The elastic constants and Vickers hardness suggest that LaMO3 are mechanically stable and soft materials. The B/G ratios indicate that all of LaMO3 are ductile except LaVO3 and LaCrO3.The LaCrO3 has the highest Debye temperature, while LaVO3 has the lowest Debye temperature. © 2017 Informa UK Limited, trading as Taylor & Francis Group


Zhang B.,North China University of Water Conservancy and Electric Power
Philosophical Magazine | Year: 2017

Several novel ultra-incompressibility compounds TM2B (TM = Mo, W, Re and Os) have been predicted by means of the first-principles calculations. Those novel compounds were assumed to have a ReB2-type structure [P63/mmc space group (No.194, Z = 2), atomic sites: TM 4f (2/3, 1/3, z), B 2c (1/3, 2/3, 1/4)]. We calculated the mechanical properties of the TM2B, and the results reveal that they exhibit brittle behaviour and mechanically stable. The hardness values are 23.8 GPa, 23.3 GPa, 26.6 GPa and 26.3 GPa for Mo2B, W2B, Re2B and Os2B, respectively, which suggests that they are hard materials. Additionally, we found that the anisotropy of Re2B is weaker than the others. Finally, the Mo2B has the highest Debye temperature (905.8 K), while Os2B has the lowest Debye temperature (615.5 K). We hoped that our results can help to offer a theoretical data for future experimental work and application of TM2B. © 2017 Informa UK Limited, trading as Taylor & Francis Group


Wang Y.,North China University of Water Conservancy and Electric Power
Nonlinear Analysis, Theory, Methods and Applications | Year: 2016

In the very recent work Wang and Wang (2014) proved that the initial value problem for the three dimension incompressible MHD equations has a global solutions (u,B)∈C([0,∞);χ−1), provided that the norms of the initial data are bounded exactly by the minimal value of the viscosity coefficients. In this paper, we prove that global solutions u,B that was obtained in Wang and Wang (2014) is asymptotic to zero in sense of the norm of the space χ−1 as time goes to infinity. Moreover, stability of global solutions is also discussed. © 2015 Elsevier Ltd


Wang Y.,North China University of Water Conservancy and Electric Power
Boundary Value Problems | Year: 2015

In this short article, the initial value problem for the 3D magneto-micropolar fluid equations is investigated. Some new blow-up criteria of smooth solutions in terms of the vorticity and the velocity in a homogenous Besov space are established, respectively. © 2015, Wang.


Wang Y.,North China University of Water Conservancy and Electric Power
Boundary Value Problems | Year: 2013

In this paper, a regularity criterion for the 3D magneto-micropolar fluid equations is investigated. A sufficient condition on the derivative of the velocity field in one direction is obtained. More precisely, we prove that if ux3 belongs to L?(0, T; L?(R3)) with 3 ? + 2 ? ≤ 1 and ? ≥ 3, then the solution (u, v, b) is regular. © 2013 Gao and Gao; licensee Springer.


Yan S.-Q.,North China University of Water Conservancy and Electric Power
Journal of Materials Science: Materials in Electronics | Year: 2014

BiPO4:Eu3+, BiPO4:Sm3+, and BiPO4:(Eu3+, Sm3+) powders were synthesized by a hydrothermal route. The X-ray diffraction and Fourier-transform infrared spectroscopy results show that the samples are pure hexagonal phases. The excitation spectrum of BiPO4:Eu3+ sample shows the characteristic absorption peaks of Eu3+ corresponding to the direct excitation from the ground state to the higher excited states of the europium f-electrons. The excitation spectrum of BiPO4:Sm3+ sample consists of several narrow excitation lines due to the characteristic f-f transition of Sm3+. The emission spectrum of BiPO4:Eu 3+ specimen excited by 395 nm consists of lines mainly locating in the red area. The emission spectrum of BiPO4:Sm3+ sample is composed of four emission bands, which are attributed to transitions from 4G5/2 excited state to 6HJ/2 (J = 5, 7, 9, and 11) ground states of Sm3+. The excitation and emission spectra of BiPO4:(Eu3+, Sm3+) samples are different from single doped BiPO4 samples. The introduction of Sm3+ can broaden and enhance the excitation intensity of Eu 3+ and improve the emission dominance of Eu3+ at 617 nm. © 2014 Springer Science+Business Media New York.


Yan S.,North China University of Water Conservancy and Electric Power
Journal of Materials Science: Materials in Electronics | Year: 2014

BiPO4:Ce3+ and BiPO4:(Ce3+, Tb3+) powders were synthesized by the method of precipitation. The X-ray diffraction patterns show that BiPO4:Ce3+ and BiPO4:(Ce3+, Tb3+) samples have pure hexagonal phases. The transmission electron microscopy results show that the synthesized samples are nanoparticles. Ethylene glycol plays an important role in the formation of nanoparticles. The excitation spectrum of BiPO4:Ce 3+ sample shows the transition from the ground 2 F 5/2 state to the excited 5d states of the Ce3+ ions. The emission spectrum exhibits a strong band centered at 352 nm originating from the 5d → 4f transitions of the Ce3+ ions. The emission spectrum of the BiPO4:(Ce3+, Tb3+) sample contains both a weak emission band of the Ce3+ ions and strong green emission bands of the Tb3+ ions. The excitation and emission spectra show that there are energy transfers between Ce3+ and Tb3+ ions in the BiPO4:(Ce3+, Tb3+) sample. The energy transfers between Ce3+ and Tb3+ ions improve the emission efficiency of BiPO4:(Ce3+, Tb3+) sample. © 2014 Springer Science+Business Media New York.


Yang W.,North China University of Water Conservancy and Electric Power
Energy | Year: 2013

The DX GSHP (direct-expansion ground source heat pump), which uses a buried copper piping network through which refrigerant is circulated, is one type of GSHP (ground source heat pump). This study investigates the performance characteristics of a vertical U-bend direct-expansion ground source (geothermal) heat pump system (DX GSHPS) for both heating and cooling. Compared with the conventional GCHP (ground coupled heat pump) system, the DX GSHP system is more efficient, with lower thermal resistance in the GHE (ground heat exchanger) and a lower (higher) condensing (evaporating) temperature in the cooling (heating) mode. In addition, the system performance of the whole DX GSHP system is also higher than that of the conventional GCHP system. A DX GSHP system in Xiangtan, China with a U-bend ground heat exchanger 42m deep with a nominal outside diameter of 12.7mm buried in a water well was tested and analysed. The results showed that the performance of this system is very high. The maximum (average) COPs of the system were found to be 6.08 (4.73) and 6.32 (5.03) in the heating and cooling modes, respectively. © 2013 Elsevier Ltd.


Lv Q.,North China University of Water Conservancy and Electric Power
International Journal of Digital Content Technology and its Applications | Year: 2011

This paper presents the application of particle swarm optimization (PSO) algorithm for the simple assembly line balancing problem, SALBP-I. A new indirect encoding method for the solution of SALBP-I is developed to keep the feasibility of operation sequence. The particle that represents a feasible operation sequence (FOS) is based on a smallest position value rule. Given the FOS defined by a particle, the optimal assignment of the operations to the workstations is identified by an optimumseeking procedure with polynomial-time complexity. Then PSO is employed to find the optimum efficiently in the search space comprising the optimal assignments associated with all FOSs. The PSO algorithm is tested on a set of problems taken from the literature and compared with other approaches. The computation results show the effectiveness of the algorithm.


Zhang Y.,North China University of Water Conservancy and Electric Power
Advances in Information Sciences and Service Sciences | Year: 2012

The problem of evaluating the performance balance of computer with intuitionistic fuzzy information is the multiple attribute decision making (MADM) problems. In this paper, we investigate the multiple attribute decision making (MADM) problems for evaluating the performance balance of computer with intuitionistic fuzzy variables. We utilize fuzzy decision-making method based on the weighted correlation coefficient under intuitionistic fuzzy environment to aggregate the intuitionistic fuzzy numbers corresponding to each alternative and get the overall value of the alternatives, then rank the performance balance of computers and select the most desirable one(s) according to the weighted correlation coefficient under intuitionistic fuzzy environment. Finally, an illustrative example is given.

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