Shallow acceptors in doping epitaxial layers GaN:Si has been studied. A doping concentration was specified by temperature of Si-dopant source (T Si ). The chemical nature of the acceptors has been determinated by phot...
详细信息
Shallow acceptors in doping epitaxial layers GaN:Si has been studied. A doping concentration was specified by temperature of Si-dopant source (T Si ). The chemical nature of the acceptors has been determinated by photoluminescence (PL) method. It is shown that a dominant acceptors in GaN:Si are background impurity Mg at T Si <1350degC and Si on N state at T Si =1400degC.
Modelling of the impulse generator intended for a gas-discharge photo of biologically active points on program Micro-Cap 7.0 is realized. The choice of electronic components is proved. Graphs of an output signal, whic...
详细信息
Modelling of the impulse generator intended for a gas-discharge photo of biologically active points on program Micro-Cap 7.0 is realized. The choice of electronic components is proved. Graphs of an output signal, which show that system device requirements are executed, are presented. Oscillogram of an output voltage of the laboratory model of the device well agreed with modeling results. Safety of use of the given device in the medical diagnostic purposes is confirmed.
In article the influence of non-uniform sensitivity of cells CCD on accuracy of the gauge of coordinates of the center of ignition is considered and the way of correction thereof is offered to an error.
In article the influence of non-uniform sensitivity of cells CCD on accuracy of the gauge of coordinates of the center of ignition is considered and the way of correction thereof is offered to an error.
In article results calculation of energy the ultrasonic vibrations disseminated in a welding zone of thermoplastic materials in view of reflecting and passing properties of borders welded materials, support and the wo...
详细信息
In article results calculation of energy the ultrasonic vibrations disseminated in a welding zone of thermoplastic materials in view of reflecting and passing properties of borders welded materials, support and the working tool of oscillatory system are presented. Dependence of time necessary for bonding of materials, in view of properties, thickness, amplitude, frequency of ultrasonic welding is certain. The found criterion definition quantity of energy injected in a welding zone and time of ultrasonic influence is recommended to be used for management of ultrasonic welding process and for formation of qualitative welded connection thermoplastic materials.
Due to environmental and health demands for lead contamination, there is increasing pressure in legislation and a growing market demand to eliminate toxic materials. Lead-free soldering for the electronic industry is ...
详细信息
Due to environmental and health demands for lead contamination, there is increasing pressure in legislation and a growing market demand to eliminate toxic materials. Lead-free soldering for the electronic industry is becoming a global trend, and several alloy systems alternatives have been recommended. The present article investigates the effect of changing soldering atmosphere from air to nitrogen, time above solder liquidus temperature and peak soldering temperature on solder wetting. It has been shown that spreading is better in nitrogen: the time above liquidus temperature can be reduced by about 18% or the peak temperatures can be reduced by about 6-8 degC, resulting in the same solder-spread for the nitrogen process, as when soldering is performed in the air atmosphere.
The aim of this work was to fabricate, by means of scanning probe lithography, semiconductor micro- and nanotubes from strained GaAs/InGaAs- based film heterostructures. Using scanning probe lithography, micro- and na...
详细信息
The aim of this work was to fabricate, by means of scanning probe lithography, semiconductor micro- and nanotubes from strained GaAs/InGaAs- based film heterostructures. Using scanning probe lithography, micro- and nanotubes were obtained. It was shown possible to oxidize structures thicker than 100 nm through their entire thickness using local anodic oxidation. An advantage of local anodic oxidation is that this technique requires no resist to be used, leaving microstructures formed at previous process stages intact and therefore allowing repeated lithographic steps to be performed on one structure.
In article bases of four-item phase modulation QPSK are considered. Diagrams QPSK of a signal in time and frequency area are resulted. The basic variants of construction QPSK of modulators are considered. The method o...
详细信息
In article bases of four-item phase modulation QPSK are considered. Diagrams QPSK of a signal in time and frequency area are resulted. The basic variants of construction QPSK of modulators are considered. The method of research had been chose a method of the mathematical analysis.
In this paper proposed the high performance PLL for ubiquitous network 800 MHz ISM band. We design the PFD(Phase Frequency Detector) by using TSPC (True Single Phase Clock) circuit to improve the performance and solve...
详细信息
In this paper proposed the high performance PLL for ubiquitous network 800 MHz ISM band. We design the PFD(Phase Frequency Detector) by using TSPC (True Single Phase Clock) circuit to improve the performance and solve the dead-zone problem. CP (Charge Pump) and LP (Loop filter) is consisted of Negative feedback and current reuse circuit in order to solve current mismatch and switch mismatch problem. The VCO(Voltage controlled Oscillator) with S-stage differential ring oscillator is used to obtain exact output frequency. The divider is consisted of D-type flip flops asynchronous divider. The frequency divider has a constant division ratio 32. The frequency range of VCO has from 500 MHz to 1.1 GHz and has 1.8 GHz/v of voltage gain. The proposed PLL is based on 0.18 mum CMOS technology with 1.8 V supply voltage. PLL input frequency is 25 MHz and VCO output frequency is 800 MHz. The proposed PLL lock time is 6.5 us. It is evaluated by using cadence spectra RF tools.
暂无评论