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Simulation, device fabrication.

The graphene, as a one atomic-layer material, is very sensitive to the environment and easy to be polluted. Here, we propose an in situ fabrication and characterization method for graphene electronic devices using the Dual Beam system. Instead of the conventional photo/e-beam lithography, plasma etching and lift-off techniques, the focused ion beam (FIB) is employed to pattern the graphene and the e-beam induced deposition of platinum (Pt) is adopted to fabricate the electrodes. Using the nano-probes in the specimen chamber, we obtained the typical electronic bipolar behavior of graphene in situ both with the Pt/graphene contact and the nano-probes/graphene direct contact. In the whole process of the fabrication and characterization, the graphene sample is kept in high vacuum condition all the time.

Amino-functionalized mesoporous silica thin films (AF-MSTFs) have been directly dip-coated on silica wafers by co-condensation of tetraethoxysilane (TEOS) and 3-aminopropyltriethoxysilane (APTES) in the presence of Brij56 (C16H33(OCH2CH2)10OH) under acidic condition. Using the AF-MSTFs as templates, gold nanoparticles (GNPs) are well formed within the mesopores. The transmission electron microscope images and X-ray diffraction patterns demonstrate that the MSTFs are consistent with well ordered mesostructures and the GNPs are well crystallized in the templates. A single electron tunneling device based on self-assembled GNPs of the Au/SiO2 nanocomposite film has been fabricated by using nanolithographic definitions. The device shows Coulomb stair-cases at 77 K. The data are interpreted as single electron tunneling through the GNP which served as a Coulomb island between the source and drain electrodes. The charging energy is estimated to be much larger than the thermal energy at 77 K. The Coulomb island size calculated from the experimental data is -3.8 nm, which is consistent with the size of the GNPs self-assembled in the MSTFs.

The photo-electrical properties of few-layer WS2 nanoflakes, fabricated by mechanical exfoliation, were systematically studied in this paper. The few-layer WS2 FETs are n-type and possess a high gate modulation (On/Off ratio is larger than 10 4 ) and a relatively high carrier mobility ( 3 2 1 1 7.1 10 cm V s − − −  ). The photo-electrical properties of the device shows sensitive photo response

The process analysis of the two-order dynamic response of Laser Target Designators(LTD) and the aiming errors are introduced in the Air-borne platform LTD random position jittering simulation.The Gauss white noises and the filtered colored noises are used to simulate the dynamic statistical characters of LTD jittering facula's time-response position and diffuse reflected energy under the simplified model of targets,together with the test results of the two different kinds of materials.The analysis shows that the dynamic diffuse reflected energy is related to the movement between platform and targets,the target's surface diffuse reflection characters and surface reflection characters.The method and the results can be used in the dynamic simulation of LTD signals' atmosphere propagation and detection.

Ordered mesoporous silica thin films were prepared by one-pot co-condensation method by the surfactants Brij56, P123 and F127. They were used in template synthesis of gold nanoparticles, and three kinds of Au/SiO2 nanocomposites were obtained. The absorption spectra measured by spectrophotometer show that the extinction property of nanocomposites would be affected by their mesostructure. The experimental results show that the size of gold nanoparticles will increase and nanocomposite’s extinction spectrum will undergo a red-shift while the dipping time is increased. It was analyzed by the Maxwell-Garnett (MG) theory with a simple model of the nanocomposite. The simulative results gave a qualitative explanation of the difference of the extinction property between different kinds of nanocomposites. By regulating the dipping time or choosing a proper surfactant during the preparation of Au/SiO2 nanocomposite, we may control its extinction property.

An improved matched filter design method based on the maximum average correlation height(MACH) principle is proposed to recognize the targets in cloud backgrounds. In the process of MACH filter design, a theoretical model of power spectrum density(PSD) is established by curve fitting after statistically analyzing the real cloud backgrounds’ PSD distribution to replace the traditional white noise model. Various features of flight targets are extracted and processed by threshold to get the training set images. Correlation results of targets in various cloud backgrounds show that the average peak to correlation energy ratio is 0.71%, and the peak to clutter ratio is 0.92 of improved matched filter, the cloud backgrounds are well restrained, and the filter is also distortion-invariant to feat

Smartphones are widely used at present. Most smartphones have cameras and kinds of sensors, such as gyroscope, accelerometer and magnet meter. Indoor navigation based on smartphone is very important and valuable. According to the features of the smartphone and indoor navigation, a new indoor integrated navigation method is proposed, which uses MEMS (Micro-Electro-Mechanical Systems) IMU (Inertial Measurement Unit), camera and magnet meter of smartphone. The proposed navigation method mainly involves data acquisition, camera calibration, image measurement, IMU calibration, initial alignment, strapdown integral, zero velocity update and integrated navigation. Synchronous data acquisition of the sensors (gyroscope, accelerometer and magnet meter) and the camera is the base of the indoor navigation on the smartphone. A camera data acquisition method is introduced, which uses the camera class of Android to record images and time of smartphone camera. Two kinds of sensor data acquisition methods are introduced and compared. The first method records sensor data and time with the SensorManager of Android. The second method realizes open, close, data receiving and saving functions in C language, and calls the sensor functions in Java language with JNI interface. A data acquisition software is developed with JDK (Java Development Kit), Android ADT (Android Development Tools) and NDK (Native Development Kit). The software can record camera data, sensor data and time at the same time. Data acquisition experiments have been done with the developed software and Sumsang Note 2 smartphone. The experimental results show that the first method of sensor data acquisition is convenient but lost the sensor data sometimes, the second method is much better in real-time performance and much less in data losing. A checkerboard image is recorded, and the corner points of the checkerboard are detected with the Harris method. The sensor data of gyroscope, accelerometer and magnet meter have been recorded about 30 minutes. The bias stability and noise feature of the sensors have been analyzed. Besides the indoor integrated navigation, the integrated navigation and synchronous data acquisition method can be applied to outdoor navigation.

Amino-functionalized mesoporous silica thin films with high content of -NH2 moieties have been directly dip-coated on silicon wafers by co-condensation of tetraethoxysilane and 3-aminopropyltriethoxysilane in the presence of C16H33(OCH2CH2)10OH under acidic condition. X-ray diffraction patterns show that it is a good strategy to remove the surfactant by ethanol extraction rather than calcinations. Using the amino-functionalized mesoporous silica thin films as templates, nanoparticles arrays of gold are formed well within the mesostructures. The isolated gold nanoparticles with size of 2.4-3.9 nm are released by dissolving the silica frameworks with the help of an ethanol solution of HF, showing that the gold nanoparticles have uniform size and spherical appearance. The Ultraviolet-visible spectra show that as the size of gold nanoparticles increase when the dipping time extended, the surface plasmon resonance absorption peak shifts to a longer wavelength.

Highly ordered mesoporous silica thin films (MSTFs) were spin-coated on Si wafers by self-assemble of water-soluble nanocrystal micelles with soluble silica. The gold nanoparticles (GNPs) were assembled within the silica matrix. Based on this nanocomposite, nanoscale electrodes were fabricated to form single electron devices. Two main transport behaviors of resemblant Coulomb blockage were demonstrated in the current-voltage measurements. The Coulomb island size calculated from the current-voltage data was close to the real size of the GNPs. The random loading positions of GNPs in the MSTF, which lead to uncertain tunneling resistances, might be response for the conductive differences.

A new extremely fast and high-power laser diode driver module is introduced, which is made of a fast high-power MOSFET and based on discharging capacitor. The main factors are analysed in theory, which determine the main performance of this kind of laser diode driver module. The whole performance of the laser diode driver module is simulated with SPICE module in detail, and the testing results of the produced laser diode driver module are described. The main methods to change the output peak power and current pulse width of the laser diode driver module are presented. The output peak power of the laser diode driver module is very high, which can reach 50 W. The output current pulse width of the laser diode driver module is very short, which is less than 8 ns. The laser diode driver module can directly drive many kinds of pulse laser diode in the market, and be used as the high performance transmitter driver module of time-of-flight ladar and laser range finder.

Two kinds of mesoporous silica thin films (MSTFs), embedded with gold nanocrystals (GNCs), are synthesized using different surfactants. The MSTFs are composed of well-ordered mesostructures and the GNCs are well crystallized in the pores of the thin films. Optical absorption peaks, due to the surface plasmon resonance of the GNCs, are observed. Both classical and semi-classical methods are used to describe the dielectric function of the GNCs in the analysis, which showed that the particle size, particle shape, particle filling ratio and the matrix structure determine the absorption properties of the GNC/MSTF nanocomposite. Third-order optical nonlinearity of the nanocomposite was studied by the z-scan technique. The GNC/MSTF nanocomposites exhibited large optical nonlinearities.