The Infrared Ray Transport Model of Finite Size Flat Beam in Tissue

The infrared ray propagation model of finite size flat beam in biological tissue is set up. Gaussian beams and circularly flat beams were compared. The model is simulated with Monte Carlo method, and the influence of parameters of biological tissue and properties is analyzed. The potential application of the model is demonstrate by estimating the absorption and transport-corrected scattering coefficients from reflectance measured from intact tissue.     

Parameters to Define the Electron Beam Trajectory of a Double-Tapered Disc-Loaded Wideband Gyro-TWT in Profiled Magnetic Field

In the method of tapering the cross section of the interaction structure for broadbanding a gyro-TWT, the different portions of the interaction length of the tapered-cross-section waveguide become effective for different frequency ranges if the magnetic field and beam parameters are profiled to maintain the condition of electron cyclotron resonance throughout the interaction length. In the present paper, the study of profiling the magnetic field and beam parameters in steps of the stepped analytical model of a double-tapered disc-loaded circular waveguide was made throughout the steps of the model. In the observed profile, the magnetic flux density in a typical step relative to its value in first-step decreases from first-step (gun-end) to end-step (collector-end) of the model considering the up-tapering schemes, in which structure parameters increase from gun-end to collector-end. Also, the transverse beam velocity in a typical step relative to its value in first-step decreases from gun-end to collector-end. However, the Larmor radius in a typical step relative to its value in first-step as well as the hollow-beam radius in a typical step relative to its value in first-step, both increase from gun-end to collector-end in the model considering the up-tapering schemes.     

Omnidirectional Single-negative Gap and in Fibonacci Sequences Composed of Single-negative Materials

The band structures of Fibonacci sequence composed of single-negative materials are studied with a transfer matrix method. A new type of omnidirectional single-negative gaps is found in the Fibonacci sequence. In contrast to the Bragg gaps, such an omnidirectional single-negative gap is insensitive to the incident angles and polarization, and is invariant upon the change of the ratio of the thicknesses of two media. It is found that omnidirectional single-negative gap exists in the other Fibonacci sequence, and it is rather stable and independence of the structure sequence.     

Cr掺杂InAs自组织量子点的分子束外延生长及磁性质

利用低温分子束外延技术制备了Cr掺杂的InAs铁磁性自组织量子点.高分辨电子显微镜分析表明InAs:Cr量子点保持了较好的闪锌矿结构.超导量子干涉仪磁性测量表明InAs:Cr自组织量子点的铁磁转变温度超过400K.     

Optimized Implementation of RNS FIR Filters Based on FPGAs

In this paper optimized Residue Number System (RNS) arithmetic blocks to better exploit some of the architectural characteristics of the last generation FPGAs are presented. The implementation of modulo m adders, modulo m constant and general multipliers, input and output converters are presented. These architectures are based on moduli sets chosen in order to optimally use the 6-input Look-Up Tables (LUTs) available in the Complex Logic Blocks (CLBs) of the new generation FPGAs. Experiments based on the implementation of Finite Impulse Response (FIR) filters characterized by different number of taps and wordlengths shows that the use of RNS together with suitable moduli sets optimally fits the 6-input LUTs in the last generation FPGAs architectures.     

Analysis of class E amplifier with both linear and nonlinear shunt capacitance at any duty cycle,grading coefficient and supply modulation

This work studies the effects of the drain pn capacitance grading coefficient, duty cycle and supply modulation on the operation of class E amplifier. The class E operation analysis with a combination of nonlinear and linear output capacitances is revisited and duty cycle is added to the equations to allow further investigations for optimum class E circuit tuning. The presented analysis method can be used for synthesis as well, where necessary load components are calculated for a transistor with a specific grading coefficient both in the output capacitance and in the nonlinear feedback capacitance. Further, the grading coefficient of the nonlinear output capacitance is varied in the paper while investigating the changes in normalized peak voltages and harmonics. Drain efficiency, supply-to-amplitude modulation (V _dd /AM) and supply-to-phase modulation (V _dd /PM) are studied. It is shown that by varying the device duty cycle, one can scale the optimum load and the level of peak voltages over the switching device. Also, the choice of grading coefficient affects the drain efficiency, V _dd /AM and V _dd /PM behaviour of the class E amplifier. Last, a case study about increasing the efficiency of a class E amplifier with hyperabrupt output junction capacitance is shown.     

Flexible,Low-loss Waveguide Designs for Efficient Coupling to Quantum Cascade Lasers in the Far-infrared

We coupled linearly polarized and azimuthally polarized Terahertz quantum cascade lasers (QCLs) to the low-loss optical modes of hollow core waveguides having a sequence of different metallic or dielectric inner coatings. The latter waveguides have been specifically designed to force the propagation of a dominant optical mode once the thickness (d) of the inner dielectric coating is properly chosen. Our results demonstrate that both the TE01 and the TE11 modes can be easily converted to a hybrid one when d > 6 μm allowing the propagation of THz QCL beams with transmission losses as low as 1.5 dB/m, bending losses < 1.1 dB and reasonably high coupling efficiencies (87%).     

Heterogeneous Vehicle Navigation Platform Combined with Mobile RFID Using MIMO System

In a mobile Radio Frequency Identification (RFID) system, the RFID tag is attached to a mobile object such as a vehicle, a human etc. The information is more difficult to detect than in the case where the tag is attached to a stationary object. The RFID reader and back-end database both help to automatically record and store the vehicle driver information and real time status of a tracked geographic information system (GIS), and they cooperate to synchronize the information flow and monitor. In this paper, the Kalman filter (KF) has been implemented as the primary integration scheme of the global positioning system (GPS) and inertial navigation systems (INS) for many land vehicle navigation and positioning applications. It also includes estimating the state of dynamic systems, almost all systems have some dynamic component, and determine how to best use a given set of vehicle sensors for modeling a high performance analysis by using the KF algorithm.     

Large Scale Indoor Localization System Based on Wireless Sensor Networks for Ubiquitous Computing

The task of formulating an efficient system for determining the location of an object, results in the creation of a wide number of applications and services. For this reason, most wireless sensor network applications assume the availability of sensor location information. In this paper, an indoor localization scheme, which is based on synchronized sensor nodes, is proposed. It is efficient in terms of power consumption and location update rate. Furthermore, it resolves the scalability problem usually found in most conventional indoor localization systems in large scale indoor environments. The performance of the proposed scheme is evaluated through experimental implementation and is compared with the Cricket system. The results demonstrate that the proposed scheme is a promising and feasible localization system for a large scale indoor environment.     

Using Data Contention in Dual-ported Memories for Security Applications

Field Programmable Gate Arrays (FPGA) provide the invaluable feature of dynamic hardware reconfiguration by loading configuration bit files. However, this flexibility also opens up the threat of theft of Intellectual Property (IP) since these configuration files can be easily extracted and cloned. In this context, the ability to bind an application configuration to a specific device is an important step to prevent product counterfeiting. Furthermore, such a technology can also enable advanced business models such as device-specific feature activation. In this work, we present a new technique to generate entropy on FPGA device—based on data contention in the hardware circuitry. For this entropy, we use the output of intentionally generated write collisions in synchronous dual-ported block RAMs (BRAM). We show that the parts of this output generated by such write collisions can be either probabilistic but also deterministic and device-specific. The characteristics of such an entropy source can be used for a large variety of security applications, such as chip identification and device authentication. In addition to that, we also propose a solution to efficiently create cryptographic keys on-chip at runtime. As a last contribution, we eventually present a strategy how to transform this entropy source into a circuit for True Random Number Generation (TRNG).