Electrodynamically actuated on-chip flow cytometry with low shear stress for electro-osmosis based sorting using low conductive medium

In the proposed paper, we demonstrate on-chip electrodynamically driven actuator flow cytometry, based on negative dielectrophoretic (nDEP) focus and alternating current electro-osmotic flow (ACEOF) sorting technique. This single chip can perform three different functions such as focusing, transportation of beads/cells to detection site and reloading the unsorted ones with two distinctive phenomena. AC EOF is achieved by the design of the asymmetric electrode pair’s array and nDEP is used to focus the beads/cells in-line. The design, simulation and experimental results of the proposed microchip are reported in this paper. The simulation and experimental results reveal well defined stable region for nDEP and ACEOF driving force. The potential severe shear stress damage caused by the sheath flow in conventional flow cytometry is eliminated. In addition, to explore the influence of conductivity of the medium, we have used low conductive formulated medium with conductivity of 81.4 μS/cm. The voltage and the frequency required to manipulate the particles decreased comparatively with the use of this medium.     

Influence of glycerol on the mechanical reversibility and thermal damage susceptibility of collagenous tissues

Clinical procedures wherein supraphysiologic temperatures must be achieved in deep layers of tissue via light are often compromised by optical scattering and absorption. Optical clearing of tissue superficial to the target improves the efficacy of such procedures. Glycerol is an attractive chemical agent for achieving dramatic reductions in tissue turbidity, but its net effects on healthy tissue are not fully understood. In this paper, we investigate possible alterations of biaxial mechanical properties in a model collagenous tissue, bovine epicardium, induced by glycerol. Furthermore, we examine the effects of glycerol on the biaxial thermomechanical properties of epicardium constrained at near-physiologic length. It is seen that mechanical changes induced by glycerol are fully reversed upon rehydration in normal saline. Moreover, glycerol protects cleared tissue by increasing its thermal stability and minimizing thermal alterations of mechanical properties.     

Analysis and design of high-speed and low-power CMOS PLAs

The programmable logic array (PLA) is a basic and important building circuit for VLSI chips. Operating behaviors of several conventional PLAs are analyzed first to find out their speed and power bottlenecks. Then, new circuit design techniques for the CMOS PLA are proposed in the hopes of fulfilling the requirements of high speed and low power at the same time. Finally, high speed is achieved through the combined effect of utilization of a fast pseudofootless dynamic circuit and a reduced interplane clock delay. On the other hand, low power is achieved because the power consumption from the three main sources, i.e., the AND-plane circuits, the interplane buffers, and the OR-plane circuits, can be reduced significantly and simultaneously. The delay time and the power consumption of the critical path of a PLA are taken as the performance evaluation parameters. When the 50×50×64 PLAs are designed in a 0.35-μm 1P4M CMOS technology, the maximum operating frequency of the proposed PLA is 1.61 times higher than that of the fastest conventional PLA. Furthermore, power reduction can be as high as 18% and 43% when the operating frequencies are set to be 100 MHz and 50 MHz, respectively, as compared to the most power-efficient conventional PLA     

Constructing secure group communication over wireless ad hoc networks based on a virtual subnet model

Recently, more and more people have begun using mobile devices such as PDAs and notebooks. Our lives have been profoundly affected by such devices. A MANET, a mobile ad hoc network, is an effective networking system facilitating an exchange data between mobile devices, without the support of wireless access points and base stations. A MANET is not restricted to unicast or multicast communication, but can also provide "many-to-many" transmission, which can be treated as a group communication. Until recently, however, the way in which such groups are formed had not drawn much attention. Because communication in wireless networks is broadcast and a certain amount of devices can receive transmitted messages, the risk of unsecured sensitive information being intercepted by unintended recipients is a real concern. Consequently, efforts to ensure the security of group communications in MANETs are essential. This article proposes a virtual subnet model to construct secure group communication over a MANET. With the model, the composition of groups is established as the forming of group keys. Our results show that this approach can completely satisfy the needs for both security and efficiency.     

Reliability of the doping concentration in an ultra-thin body and buried oxide silicon on insulator (SOI) and comparison with a partially depleted SOI

This study compares the reliability of nMOSFETs with low- and high-doped ultra-thin body and buried oxide (UTBB) with fully depleted (FD) and partially depleted (PD) silicon on insulator (SOI). The high-doped devices display lower off-current leakage performance but more degradation in both hot-carrier stress (HCS) and positive bias temperature instability (PBTI) test at both room temperature and elevated temperature compared with the low-doped devices. The PBTI test indicates that the high-doped devices induce high tunneling leakage and that the degradation is highly associated with temperature. The degradation stabilizes with an increase in stress time. The thinner PD-SOI demonstrates low variation at the threshold voltage and low drive current under HCS. The FD-SOI has better drain leakage control than the PD-SOI.     

Co-channel interference in high capacity fixed wireless loops (FWL)

The importance of the incident power density pattern (IPDP) for future fixed wireless loop (FWL) systems is discussed. Also an investigation into some of the important S/I implications of the IPDP for proper system capacity simulations is presented     

Noise reduction of VQ encoded images through anti-gray coding

Noise reduction of VQ encoded images is achieved through the proposed anti-gray coding (AGC) and noise detection and correction scheme. In AGC, binary indices are assigned to the codevector in such a way that the 1-b neighbors of a code vector are as far apart as possible. To detect the channel errors, we first classify an image into uniform and edge regions. Then we propose a mask to detect the channel errors based on the image classification (uniform or edge region) and the characteristics of AGC. We also mathematically derive a criterion for error detection based on the image classification. Once error indices are detected, the recovered indices can be easily chosen from a “candidate set” by minimizing the gray-level transition across the block boundaries in a VQ encoded image. Simulation results show that the proposed technique provides detection results with smaller than 0.1% probability of error and more than 86.3% probability of detection at a random bit error rate of 0.1%, while the undetected errors are invisible. In addition, the proposed detection and correction techniques improve the image quality (compared with that encoded by AGC) by 3.9 dB     

A Provably Secure Multi-server Based Authentication Scheme

With the rapid growth of electronic commerce and demand on variants of Internet based applications, the system providing resources and business services often consists of many servers around the world. So far, a variety of authentication schemes have been published to achieve remote user authentication on multi-server communication environment. Recently, Pippal et al. proposed a multi-server based authentication protocol to pursue the system security and computation efficiency. Nevertheless, based on our analysis, the proposed scheme is insecure against user impersonation attack, server counterfeit attack, and man-in-the-middle attack. In this study, we first demonstrate how these malicious attacks can be invoked by an adversary. Then, a security enhanced authentication protocol is developed to eliminate all identified weaknesses. Meanwhile, the proposed protocol can achieve the same order of computation complexity as Pippal et al.’s protocol does.     

A low-power 2/5.8-GHz dual-wide-band CMOS LC-VCO with switched-inductor technique

A fully integrated dual-band LC voltage control oscillator, designed in a 0.18-µm CMOS technology for 5.8-GHz/2.0-GHz wireless communication applications, is described. The frequency band switching is accomplished with switched-inductor technique. The dual-band oscillator can be operated in 5.38–6.23?GHz and 1.78–2.07?GHz with 15% frequency tuning range. Two different inductors are used for the frequency band switching. Frequency tuning is implemented by varying the capacitance of a MOS varactor. The measured phase noise is ?109?dBc/Hz @ 1?MHz and ?112?dBc/Hz @ 1?MHz for frequency at 5.8?GHz and 2?GHz, respectively. This oscillator is fabricated in UMC's 0.18-µm one-poly-six-metal 1.8?V process. The power dissipation of this dual-band VCO is 11.7 and 9.3?mW for oscillation frequency of 2?GHz and 5.8?GHz, respectively.     

Nitride-Based ultraviolet metal-semiconductor-metal photodetectors with a low-temperature GaN layer

The GaN metal-semiconductor-metal (MSM) ultraviolet (UV) photodetectors with a low-temperature (LT)-GaN layer have been demonstrated. It was found that we could achieve a two orders of magnitude smaller, photodetector-dark current by introducing a LT-GaN layer, which could be attributed to the larger Schottky-barrier height between the Ni/Au metal contact and the LT-GaN layer. It was also found that photodetectors with the LT-GaN layer could provide a larger photocurrent to dark-current contrast ratio and a larger UV-to-visible rejection ratio. The maximum responsivity was found to be 3.3 A/W and 0.13 A/W when the photodetector with a LT-GaN layer was biased at 5 V and 1 V, respectively.