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In the face of increasingly serious grassland desertification, state and local governments have implemented a series of grassland protection policies. In 2003, Ningxia was the first to implement a region-wide grazing ban and the effect of the ban has become both contentious at all levels of government and a topic of public concern. Grassland desertification in the study area is the most direct indicator...
To raise the polishing efficiency of polycrystalline diamond (PCD) superhard material, crank rocker arm mechanism has been developed by using computer simulation technology. On the basis of kinematics and geometry principle, the mathematical model for the crank rocker arm mechanism was established. The movement path and the instantaneous speed of the workpiece center point on the crank rocker arm...
Wafer-level integration of GaAs enhancement-mode pHEMT, depletion-mode pHEMT and HBT (H2W is the code name at WIN) is a very appealing technology, which offers a number of significant advantages over conventional device technologies. In this paper, we report the development and mass-production status of the H2W at WIN Semiconductors. In addition to the device fabrication, we also demonstrate a single-chip...
Contamination flashover is the ultimate result of the creeping discharge of polluted insulators. Since there are close ties between the contamination flashover and the leakage currents, it is critical to research the leakage current characteristics during the entire contamination discharge process. The leakage currents of porcelain and glass insulators are monitored and analysed through a number of...
It was found that the dependence of the breakdown field E1mA and the activation energy, on Ag content are similar to that of the exponent of alphalf in low frequency region and alphahf in high frequency region on Ag content, which is a novel result in the research of varistor materials. By means of normalization of conductivity, it was found that samples with different Ag contents show similar mechanism...
Investigation on the dielectric properties of CaCu3Ti4+xO12+2x was carried out when x was altered in the range from -0.5 to 0.5. For x= -0.5, it was found through XRD that besides primary CCTO phase, there are also CuO and CaTiO3 phases. For x= 0.5, additional TiO2 was found besides dominating CCTO phase. When x increases from -0.5 to 0.5, it was found that dielectric constant decreases, varistor...
The Compact High Resolution Imaging Spectrometer (CHRIS) is aboard the ESA PROBA satellite. CHRIS acquires imagery from 415 nm to 1050 nm in five preprogrammed modes. In mode 4, CHRIS acquires 18 bands with emphasis on the red-edge at the full spatial resolution of 18 m. CHRIS acquires 5 hyperspectral images over an angular range of 55 degrees along track. In 2004, five clear CHRIS image sets were...
This research first presents a hybrid quadrature polar modulator to drive the power amplifier (PA) highly efficiently in a wireless RF transmitter required for multi-mode operation. The proposed modulator consists of a quadrature modulator for processing the RF modulated carrier and a class-S modulator for processing the envelope signal. Since both quadrature and class-S modulators deliver signals...
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