Disclosed is a method for testing dynamic model parameters of a wind power plant. The method comprises: under the conditions that a wind power plant unit and a reactive power compensation device operate steadily, a wind speed is stable and is between a cut-in wind speed and a rated wind speed, and the wind power plant force output is smaller than a rated force output, a wind speed transient disturbance test, a wind power plant tripping/input unit disturbance test, a wind power plant power variation test, a wind power plant reactive power compensation device disturbance test, a near-wind farm water and fire power plant tripping machine disturbance test and a manual uniphase grounded short circuit test at the wind power plant outgoing line part are completed, and an operation curve of the wind power plant under each condition is recorded, so as to complete parameter test. The advantage of providing accurate measurement data for power system stability analysis and power grid production scheduling is realized.
The techniques for the cooling of the first crystal of a monochromator are by now mature and are used routinely to deal with the heat loads resulting from the intense beams generated by third generation synchrotron insertion device sources. However, the thermal stability of said monochromators, which crucially depends on proper shielding of X-ray scattering off the first crystal, remains a serious consideration. This will become even more so in the near future, as many synchrotron facilities are upgrading to higher beam currents and energies. During a recent upgrade of the 17-ID beamline at the APS it was recognized that accurate simulation of the spatial distribution of the power scattered off the first crystal was essential for the understanding and remediation of the observed large temperature increase of the first crystals scattering shield. The calculation is complex, due to the broad energy spectrum of the undulator and the prevalence of multiple X-ray scattering events within the bulk of the crystal, thus the Monte Carlo method is the natural tool for such a task. A successful simulation was developed, for the purpose of the 17-ID upgrade, and used to significantly improve the design of the first crystals scattering shield. (c) 2013 Elsevier B.V. All rights reserved.
A foam dust suppression transfer system and a foam container assembly. The foam dust suppression transfer system reduces the powder thickness at the outlet of a guide chute. The system essentially comprises a foam container assembly (1), a compressed air assembly (2), liquid storage assembly (3), a mixing assembly (4), a first electric control assembly (5), a second electric control assembly (6), a pneumatic two-way assembly (7), a liquid-level control assembly (8), and a spot-control assembly (9). The liquid-level control assembly (8) monitors and controls the liquid level of mixed liquid in the foam container assembly (1). The spot-control assembly (9) controls whether the corresponding foam container assembly (1) produces foam. The foam container assembly essentially comprises a press bar (113), a foam guide plate (114), and a partition (111). The partition (111) divides a container (101) into a foam-production cavity (115) and a foam-release cavity (116). Under the guidance of the foam guide plate (114) the foam forms a foam curtain.
Air flow and pollutant dispersion characteristics in a real valley city are studied under the real boundary condition. The 3D computational fluid dynamics using Reynolds-averaged Navier-Stokes modeling was carried out in Lanzhou which is a typical valley city in Northwest, China. The standard kappa-epsilon turbulence model as a simplified computational fluid dynamics model is used to provide moderately fast simulations of turbulent airflow in an urban environment. The modeled flow field indicated that the geometry, wind direction and source location had a significant effects on the flow field. The flow shows the funnelling is rather obvious when the wind flow through the narrow area in the middle of the city. It is obvious that in the high-altitude region, due to the impact of high and low differential pressure and terrain, SO 2 and NO 2 formed two cyclic concentration field in the dispersion process.
Huang, Rong
Wang, Jiaqi
Mao, Wuxiang
Fu, Boshi
Xing, Xiwen
Guo, Ge
Zhou, Xiang
DNA modification, a significant epigenetic event, largely affects genes' binding with the transcription factors and some other DNA binding proteins. Among DNA modifications, methylation, especially cytosine methylation is of great importance and attracts extensive studies as it leads to the silence of tumor-suppressor gene expression. In this work, a novel combined bisulfite Uracil-DNA glycosylase (UDG) assay has been developed on the basis of bisulfite modification to generate uracil from cytosine, subsequent UDG-mediated uracil elimination and ultimate DNA cleavage in alkaline condition. This strategy can be used to selectively detect exact number and loci of 5-methylcytosine residues regardless of sequence context. Moreover, it provides linear quantitative results of DNA methylation level across a wide range. (C) 2013 Elsevier B.V. All rights reserved.
The aim of this article is to examine, from a tourism perspective, the experience of Chinese international students in the UK. Three hundred twenty-one usable questionnaires were collected. This research suggests that the travel motivations of the students fall into the following four categories: relaxation, self-improvement, experiencing culture, and adventure. Certain similarities and differences of the travel behavior patterns between Chinese international students in the UK and their compatriots in Australia, New Zealand, and the United States were identified. Chinese students in the UK are generally satisfied with their travel experience in the UK. Furthermore, they are loyal customers, which is illustrated by their high intention of repeat visits and recommending the UK to friends/family. More than 42% of them had had visits from their families back in China since they arrived in the UK to study; this provides strong evidence for their importance to the visiting friends and relatives (VFR) market in the UK. The implications of these findings to educational institutions and the tourism industry in the UK are also discussed.
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