The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Nonlinear ultrasonic measurements has been proposed to characterize the creep damage evolution of P92 martensitic ferritic steels at a temperature of 650 °C and stresses of 100 MPa and 115 MPa, respectively. The correlation of increase-decrease-increase between the ultrasonic nonlinearity and the creep strain was achieved for both sets of specimens. Considering the metallographic studies, nonlinear...
P92 martensitic ferritic steels are an attractive material for critical components in power industries due to the excellent creep property. However, these steels are usually susceptible to creep strength degradation during a long service period under the elevated temperature and pressure. Creep damage evaluation is of concern to quantitatively assess the remaining lifespan of the critical components...
Because of excellent electrical properties, epoxy resin is widely used in packaging and casting power equipment. Moisture and temperature in the environment are inclined to seriously affect the insulation tolerance of epoxy resin. This work focuses on the aging characteristics of epoxy resin in hygrothermal environment. The effect of hygrothermal aging on the properties of epoxy resin was deeply studied...
We applied advanced heat dissipating technology to reduce heat resistances of the key devices to increase the output power density of the inverter. The IGBT modules were direct water-cooled, and the integrated DC-link capacitor was indirect water-cooled. We conducted the simulation and the test, which proved that reducing the heat resistances was effective to improve the output density of the inverter...
Acoustic temperature field reconstruction is an illposed problem. This means especially that their solution is unstable under data perturbations. Numerical methods that can cope with this problem are the so-called regularization methods. The choice of a regularization parameter has an important influence on reconstruction accuracy. In this paper, a 3D acoustic temperature field reconstruction algorithm...
Dry and wet deposition of inorganic nitrogen species were monitored at one urban (SDS) and one rural (TFS) site during September 2009 and August 2010 at Urumqi in a semi-arid region. Atmospheric concentrations of NH3, NO2, HNO3, particulate ammonium and nitrate (pNH4+ and pNO3-) concentrations and NH4-N and NO3-N concentrations in precipitation showed large monthly variations and averaged 7.0, 18...
A simple method to determine the power dissipation dependent thermal resistance and the junction temperature of a power AlGaN/GaN HEMT proposed. The method is based on a rigorous mathematical treatment of the nonlinear characteristics of thermal resistance. It is hence suitable for modeling of transistors operating at any power densities. This method has been verified by an accurate predicting of...
In this work, TiO2 nanoparticles doped with holmium (III) ion have been prepared by an ultrasonic assistant sol-gel method. We present the results of the investigation of holmium (III) ion doping on the structural properties of TiO2 and its effect on the anatase to rutile phase transformation. It is found that the transformation temperature, measured from the XRD experiments, is found to increase...
Three-dimension dynamic differential heat conduction equation without inner heat source was used to describe heat transfer through underground building envelope. Then a two-dimension dynamic model was established by suitable simplification without considering heavy underground water. In this paper, in order to verify the model, MATLAB is chosen as the tool to simulate the heat transfer through envelope...
The testing system based MEMS inertial devices is a kind special measurement system which is integrated with MEMS inertial sensor, ASIC and its corresponding software. Because of having merits such as small bulk, low cost, light weight, high reliability, and anti-harsh environments, it is widely used in the military and civil fields, especially suited for the high-g guided ammunition, but use what...
Big error of locating control points of anamorphic vision image calibration cause it difficult to calibrate of dynamic image automatically and accurately. Accordingly, a new calibrating method based on pattern matching is put forward. It locates the control points accurately; and builds the polynomial modeling of the anamorphic image, chooses the optimum polynomial order and calibrates the image distortion...
In this paper, it is researched that how I-V characteristics and piezoresistance coefficient of GaAs-based HEMT-embedded accelerometer change when different temperatures are set. It is shown that saturation current of device would go down if the temperature goes up, which is about 3.1467mA/°C, based on the research. However, the device can work well at the temperature range of -50°Cto 50°C, which...
Gas turbine is a complex, strong non-linear and multi-variable coupling pneumatic thermodynamics system. Its typical model in stability studies consists of load-frequency control, temperature control, and acceleration control. A strong coupling relationship exists among three control systems which affect the rotate speed of turbine and the exhaust temperature of turbine. A decoupling control method...
A hot spot is a localized high temperature zone in a grain bulk and normally spoilage begins in this location. Acoustic temperature tomography for detecting a hot spot in grain bulk is investigated. The region monitored is assumed to be square and divided into 400 pixels. 16 sound sources/receivers are set on its periphery. An acoustic temperature field reconstruction algorithm based on inverse multiquadrics...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.