Time filter

Source Type

Chen J.Z.,Xuchang Vocational Technical College
Applied Mechanics and Materials | Year: 2014

With the rapid development of network technology and the emergence of a variety of applications, network security issues became the top priority of the network applications. This article first explains the concept of buffer overflow, and then from the programming language itself flawed, not robust perspective on the emergence, to the emergence of buffer overflow attacks and principle are analyzed in detail, described hackers using buffer overflow attacks the general process, and according to the type of buffer overflow attacks, software development and program runs from two aspects of proposed buffer overflow attack prevention strategy. © (2014) Trans Tech Publications, Switzerland.

Wang W.,Xuchang University | Chu Y.M.,Xuchang Vocational Technical College
Applied Mechanics and Materials | Year: 2014

DFIG based wind power generation system was connected to power grid with voltage source converters, the rotor side converter was analyzed and the control strategy was taken, the voltage and flux equations of the DFIG was analyzed, stator flux-oriented for RSC was adopted in the control system and with the control design based on stator flux-oriented (SFO) vector control. The RSC controller of DFIG was a double closed loop system, the rotor current control loop and power control loop was designed with PI, and the simulation shows the control feature. © (2014) Trans Tech Publications, Switzerland.

Yun Y.,Xuchang Vocational Technical College | Cui F.,Henan Normal University | Geng S.,Henan Normal University | Jin J.,Henan Normal University
Luminescence | Year: 2012

A novel method for the sensitive determination of bismuth(III) in pharmaceutical products using phosphoric acid as a molecular probe by resonance light scattering (RLS) is discussed. In 0.5 mol/L phosphoric acid (H 3PO 4) medium, bismuth(III) reacted with PO 4 3- to form an ion association compound, which resulted in the significant enhancement of RLS intensity and the appearance of the corresponding RLS spectral characteristics. The maximum scattering peak of the system existed at 364 nm. Under optimal conditions, there was linear relationship between the relative intensity of RLS and concentration of bismuth(III) in the range of 0.06-10.0 μg/mL for the system. A low detection limit for bismuth(III) of 3.22 ng/mL was achieved. The relative standard deviations (RSD) for the determination of 0.40 and 0.80 μg/mL bismuth(III) were 2.1% and 1.1%, respectively, for five determinations. Based on this fact, a simple, rapid, and sensitive method was developed for the determination of bismuth(III) at nanogram level by RLS technique with a common spectrofluorimeter. This analytical system was successfully applied to determine the trace amounts of bismuth(III) in pharmaceutical products, which was in good agreement with the results obtained by atomic absorption spectrometry (AAS). Copyright © 2011 John Wiley & Sons, Ltd.

Feng C.Y.,Xuchang Vocational Technical College
Advanced Materials Research | Year: 2013

Enhanced Geothermal Systems represent a series of technology, which use engineering methods to improve the performance of geothermal power plant. In some geothermal fields, the rocks are in high temperature but a low permeability, or the subsurface water is scarce. In these geological conditions, cool water was injected into the geothermal wells to fracture the tight rock and create man-made reservoir for thermal exploitation. Furthermore, these engineering methods can be utilized to improve the productivity of pre-existing hydrothermal power plants. To save water and treat the global warming, using carbon dioxide instead of water as working fluid was proposed. Numerical simulation reveals that the carbon dioxide has numerous advantages over water as working fluid in the heat mining process. The precipitation caused by carbon dioxide will restore part of carbon dioxide in the rock and reduce the micro-seismicity risk. © (2013) Trans Tech Publications, Switzerland.

Bo Y.,Xuchang University | Huang B.,Xuchang University | Zhang Y.,Xuchang University | Wang J.,Xuchang Vocational Technical College | And 2 more authors.
Powder Technology | Year: 2014

Biomorphic CuO crystals with ordered hierarchical micro- and nanostructures were fabricated via a simple one-step thermal decomposition of CuSO4·5H2O precursor by using various biotemplates. The products were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), UV-vis spectrometer (UV-vis), Fourier transform infrared (FTIR) and Raman spectroscopy. The primary morphologies of the biomorphic CuO were determined on different biotemplates, and the size of the secondary CuO crystals was well controlled by the varying of calcination temperature. This simple thermal decomposition method provides a cost-effective and eco-friendly route for the preparation of metal oxide semiconductors. © 2014.

Discover hidden collaborations