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We report low-frequency electrical resistance noise of Co40Fe40B20/MgO/Co20Fe60B20-based magnetic tunnel junction field sensors with reference and sensing layer magnetization directions along the out-of-plane and in-plane directions, respectively. The devices are fabricated using the sputter deposition and conventional lithography techniques with a short axis of $\sim 6~\mu \text{m}$ long and long axes of $\sim 6$ –12 $\mu \text{m}$ long. Noise power spectra under different bias currents indicate increase in noise power with increasing bias current. A close 1/ $f$ dependence of the noise according to Hooge’s relation, $S_{V}(f)= AV^{2}/f^{\alpha }$ ( $A$ is Hooge’s like constant) is observed with an average value of $\alpha = 1.03 \pm 0.08$ . In smaller devices, the magnetic field dependence of noise amplitude follows similar trend of magnetoresistance (MR) behavior without any distinct peak near antiparallel–parallel states transition of the devices, which is generally observed for magnetic defects-induced resistance fluctuation. The experimental observations infer the resistance noises in those devices that are related to the defects associated with the spin independent charge trapping at structural defects near or in the barrier layer. The device with the smallest lateral size exhibits the Lorentzian contribution, whereas the device with the largest size shows magnetic contribution in total noise. Numerically deduced magnetic fluctuations $\Delta B_{\mathrm{rms}}$ of all the devices shows an average magnetic fluctuation of $\sim 10$ nT except for one device. The devices show the highest MR% of $\sim 27$ % under perpendicular magnetic field with a dynamic range of $\sim \pm 25$ Oe and a sensitivity of $\sim 0.3$ %/Oe. The observed low-frequency noise levels are suitable for the perpendicular field detection application and can be reduced more by improving the crystallinity of the device films stacks and their interfaces.

Here, we investigate the size effect of perpendicular-anisotropic double-barrier magnetic tunnel junction (MTJ) devices embedded with iron nanoparticles. A sputtering system in conjunction with the postannealing process is employed to prepare the sheet film and standard lithography techniques followed by the ion etching technique are used to fabricate the micrometer to submicrometer MTJ devices. A strong ferromagnetic coupling is observed as we reduce the size of the device to submicrometer scale, which is due to the reduction of magnetostatic energy of the device. Furthermore, a magnetoresistance (MR) oscillation is observed at room temperature while reducing the size of the device. MR peaks at low bias fields are believed to have magnon contributions, whereas the peaks observed at higher bias fields are responsible for phonon-assisted tunneling. Zero-bias anomalies are also observed and are more prominent in antiparallel states of the devices.

Molecular communications is emerging as a promising paradigm for nanoscale communications in nanotechnology. Though still at an early stage, research efforts have been devoted and various molecular communication systems have been proposed. However, each proposed system possesses a specific structure to achieve communications in its own way. To our best knowledge, no unified system description exists so far. In this paper, we propose an abstract system structure called an event-driven system ; a significant group of molecular communication systems can be classified into such an abstract form. We define event-driven systems and further show that, for these systems, there is a signaling scheme called asynchronous information embedding which carries additional information while at the same time keeping the original communication mechanisms uninfluenced. Instead of investigating asynchronous information embedding in full generality, we consider synchronous type-based systems as a demonstrative example which still captures most of the features. For such type-based systems, we develop an approximation method for obtaining the channel capacity as a general performance measure. Numerical results are provided to show the capacity gain of asynchronous information embedding.

In molecular communication systems, information is conveyed via nanoscale particles or molecules. Traditionally, the distribution of the first arrival time to the receiver is considered for system design and evaluation if nanoscale particles or molecules are diffused from the transmitter to the receiver in diffusion-based molecular communication systems. In this paper, we consider an extra information in the diffusion-based molecular communication system, namely the first arrival position at the receiver. A mathematical framework is developed to obtain the closed-form density function of the first arrival position for particles/molecules diffusing under constant net drift. The derived density function not only provides a novel analytical framework for existing molecular communication systems but may inspire novel molecular communication system design.

Diffusion-based molecular communications emerges due to the need for communication and networking among nanomachines, and molecular biological signaling networks. Inspired by the special molecular channel characteristics, we reveal the communication theoretical analogs with and differences from well-known wireless communications, particularly channel coding, intersymbol interference, multiple-input multipleoutput, and new design concepts in this article.

A series of lateral junctions consisting of NiFe/Al2O3/p-Si/Al2O3/NiFe have been investigated for the understanding of manipulating the electronic spin in semiconducting channel. Devices with various conducting channel lengths between two electrodes were fabricated using a top-down technique. An ion beam sputtering was used for the required film stack and an electron beam lithography in combination with ion beam etching technique were adopted for patterning. The current-voltage measurements reveal a remarkable phenomenon of current enhancement, indicating a formation of the interface state in such devices. This transport behavior associated with trapping assistance has also been demonstrated with a fitting based on Poole-Frenkel effect. The results also show that a transition from trapping assisted process to direct tunneling process occurs when the semiconducting channel length is below 1 μm. In addition, the current enhancement may be suppressed with increasing the thickness of the oxide layer.

The transport properties of stacked CoFeB (1.86)/MgO (0.2)/Fe-nanoparticles ( tFe)/MgO (0.5)/CoFeB(0.6) double barrier magnetic tunnel junctions have been characterized. In this investigation, stacked film is prepared by magnetron sputter system, annealed at 250 °, and patterned into a micron-scale device using standard electron beam lithography in conjunction with two-angle ion beam etching. First, the structure, magnetic and electrical properties are examined by using transmission electron microscopy, alternating gradient magnetometers, and lock-in techniques. Stacked film having 1.5 nm lateral size of iron nanoparticles (sample S1) exhibits an in-plane magnetic anisotropy, nonetheless the stacked film having 2 nm lateral size of iron nanoparticles (sample S5) possesses out-of-plane magnetic anisotropy. In addition, the micron scaled S1 device displays not only a normal in-plane magnetoresistance (MR) curve but also an anomalous out-of-plane MR behavior, whereas the S5 device only barely shows magnetic response in the in-plane MR. A hysteresis-free linear region in out-of-plane MR curve has shown field sensitivity of ~ 36 Ω/Oe that is promising for magnetic field sensor applications.

In this study, the characteristics of extracellular polymeric substance (EPS) and the mechanism of fouling formation investigated using a submerged membrane bioreactor system consisting of a polytetrafluoroethylene (PTFE) membrane. During 85 days of operation, the bound EPS observed as the main component, which contributed major part of resistance to fouling. The protein to carbohydrate ratio was higher in the growth phase than in the stationary phase. The fouling resistances contributed by each individual resistances, i.e. loose cake layer, dense cake layer and internal fouling evaluated by batch fi ltration test after rinse, wash, and backwash operations respectively. The results showed that fouling of membrane and transmembrane pressure increased very quickly within 30 min of operation mainly due to resistance offered by immediate cake layer formation. The analysis of EPS contributed by different fouling layer revealed that most of the carbohydrate adsorbed quickly on the PTFE membrane first and then p...

This study presents a polyimide (PI) self-assembly technique for the development of three-dimensional surface micromachined structures. The effects of the geometric factors and the curing temperature of the PI elastic joints on the lifting angle of such microstructure are investigated. Under the optimized curing condition (380°C), a maximum 74° lifting angle of a 5.2 × 10 −11 kg-weight polysilicon microplate can achieved utilizing the large surface-tension force of a single PI joint. The lifting angle of the thermally actuated 3-D microstructures can be demonstrated in nearly directional proportion to the length/width-thickness ratio of PI joint and the temperature difference temperature.

Stealth Dicing (SD) technology has high potential to replace the conventional blade sawing and laser grooving. The dicing method has been widely researched since 2005 [1–3] especially for thin wafer (⇐ 12 mils). SD cutting has good quality because it has dry process during laser cutting, extremely narrow scribe line and multi-die sawing capability. However, along with complicated package technology, the chip quality demands fine and accurate pitch which conventional blade saw is impossible to achieve. This paper is intended as an investigation in high performance SD sawing, including multi-pattern wafer and DAF dicing tape capability. With the improvement of low-K substrate technology and min chip scale size, SD cutting is more important than other methods used before. Such sawing quality also occurs in wafer level chip scale package. With low-K substrate and small package, the SD cutting method can cut the narrow scribe line easily (15 um), which can lead the WLCSP to achieve more complicated packing method successfully.

Double barrier Magnetic tunnel junction (DBMTJ) is an attractive issue in the field of spintronics due to potential applications, such as spin diode [1], magnetic field sensor [2], and non-volatile spin-transfer-torque magnetic random access memories [3]. Essentially, the DB structures give rise to a high spin filtering efficiency, thus not only enhancing the tunneling magnetoresistance (TMR) ratio but also improving the MR decay as raising bias voltage. Therefore, many efforts have been devoted to investigating the specific phenomena in DBMTJs [4] experimentally and theoretically. Comparing to the in-planed DBMTJ, however, the perpendicular-type DBMTJs have more potential in raising the operating speed and data density. Herein, we investigate the size effect and temperature dependent behavior of perpendicular-anisotropy magnetic tunnel junction embedded with iron nanoparticles.

Historically, multiple description coding (MDC) and postprocessing error concealment (ECN) algorithms have evolved separately. In this paper, we propose a coordinated application of multiple description scalar quantizers (MDSQ) and ECN, where the smoothness of the video signal helps to compensate for the loss of descriptions. In particular, we perform a reconstruction that is consistent with the data received at the decoder. When only a single description is available, the video is reconstructed in such a way that: 1) if we were to regenerate two descriptions (from the reconstructed video), one of them would be equivalent to the received description and 2) the reconstructed video is spatiotemporally smooth. Experimental results with several video sequences demonstrated a peak signal-to-noise ratio (PSNR) improvement of 0.9-2.8 dB for intracoded frames. The PSNR improvements for intercoded frames were negligible. However, for both cases, the visual improvements were much more striking than what the PSNR improvement suggested.

Multiple description coding (MDC) is a source coding technique that exploits path diversity to increase the robustness of transmitting a compressed signal over error-prone channels. However, the application of MDC to video coding is still problematic because a prediction mismatch problem, called drift, may occur at the decoder when one description is lost. In the literature, it has been shown that drift can be effectively prevented by encoding this prediction mismatch and sending it as side information in a three-prediction-loop structure. However, this side information is totally redundant when both descriptions are received. We propose a very simple, but efficient two-stage MDC in the central prediction loop based on the three-prediction-loop structure of A. Reibman et al. (see Proc. IEEE Int. Conf. Image Processing - ICIP'99, p.837-41, 1999). We introduce an additional multiple description scalar quantizer into the central prediction loop. The encoding of the side information is modified in such a way that it can be used to improve the video quality when no drift occurs, but still maintain a drift prevention capability. The simulation results, with different video sequences at various packet loss rates, demonstrate that the proposed two-stage MDC structure indeed enhances the quality when the channel is error-free, yet effectively avoids drift when one description is completely lost.

Layered (LC) and multiple description coding (MDC) have been proposed as source coding techniques that are robust to channel errors for video transmission. LC and MDC have similar characteristics: they both generate multiple sub-bitstreams, and it is permissible to drop some portion of the data from the sub-bitstreams during transmission for both methods. However, they are different in the sense that the sub-bitstreams for LC have different levels of importance while all sub-bitstreams for MDC are equally important. Since these two encoding techniques have similar properties, some performance comparisons between LC and MDC have recently been reported. However, these studies are still not conclusive because several scenarios have not been carefully considered. Furthermore, they have been performed in different environments. In this paper, we further investigate the error-resilience capabilities of these two encoding techniques through extensive experimentation. Although some of our conclusions agree with those in the literature, we believe that this paper provides the most comprehensive performance comparison yet between LC and MDC.

Low temperature co-firable ceramics, Zn 3 Nb 2 O 8 , were developed by using V 2 O 5 species as liquid phase sintering aids. Among the range of additives examined, 2 mol% V 2 O 5 was observed to perform most satisfactory for acting as liquid phase sintering aids. The Zn 3 Nb 2 O 8 materials can be densified in wide temperature range (850–1000 °C), resulting in similar microwave dielectric constant ( K =22.4) and the same high quality factor ( Q × F =67,500). Over firing (1100 °C×4 h) causes marked degradation on Q × F -factor, without influencing the dielectric constant and density of the Zn 3 Nb 2 O 8 materials. Microstructure examination reveals that the probable mechanism is due to the rigorous interaction between the V 2 O 5 and Zn 3 Nb 2 O 8 materials, forming a lossy layer surrounding the grains.

Compressed video sequences are very vulnerable to channel disturbances when they are transmitted through an unreliable medium such as a wireless channel. Transmission errors not only corrupt the current decoded frame, but they may also propagate to succeeding frames. A number of post-processing error concealment (ECN) methods that exploit the spatial and/or temporal redundancy in the video signal have been proposed to combat channel disturbances. Although these approaches can effectively conceal lost or erroneous macroblocks (MBs), all of them only consider spatial and/or temporal correlation in a single frame (the corrupted one), which limits their ability to obtain an optimal recovery. Since the error propagates to the next few motion-compensated frames in the presence of lost MBs in an I or P frame, error concealment should simultaneously minimize the errors not only in the current decoded frame but also in the succeeding B and P frames that depend on the corrupted frame. We propose a novel multiframe recovery principle which analyzes the propagation of a lost MB into succeeding frames. Then, MPEG-compatible spatial and temporal error concealment approaches using this multiframe recovery principle are proposed, where the lost MBs are recovered in such a way that the error propagation is minimized.

This paper presents a Through-Silicon-Via (TSV) based double-side integrated microsystem for brain neural sensing applications. Figure 6.3.1 shows the structure of the double-side integrated microsystem. MEMS neural microprobe array and low-power CMOS readout circuit are fabricated on two sides of the same silicon substrate, and TSV's are used to form a low impedance interconnection between the microprobe and CMOS circuitry, thus providing the shortest signal transmission distance from sensors to circuits. The low parasitic impedance of TSV minimizes transmission loss and noise. The overall chip is 5x5mm2, 350μm in thickness including 150μm probe height and 200μm TSV height, respectively. A total of 480 microprobes is divided into 4x4 sensing areas, forming 16channels. 16 TSV arrays are used to connect the microprobe outputs to 16 readout circuits fabricated on the opposite side of the silicon substrate. The proposed structure allows stacking of other CMOS chips onto the circuit side by TSV 3D IC technique.

Due to the time-varying nature of wireless channels and the Internet backbone traffic, it is a challenging task to maintain the quality of wireless multimedia streaming throughout the transmission. An effective solution is to adapt the codec setting based on the wireless channel condition or the Internet backbone state. In this chapter, we present three cross-layer codec adaptation algorithms that adjust the codec setting in real-time based on media access control frame error rate, received signal strength indication, and path bandwidth respectively. Results show that the algorithms are effective in achieving good video quality for wireless multimedia streaming over wireless links.