Differential phase decoder in a polarized optical heterodyne interferometer

A differential-phase decoder (DPD) together with a polarization common-path optical heterodyne interferometer is set up. Based on this interferometric configuration and a novel balanced-detector scheme, the performance of the quantum-noise-limited differential-phase decoder is demonstrated and analyzed. The minimum-detectable differential phase is on the order of 10(-7) rad/sqrt Hz when a 2.5 mW He-Ne laser is used. Verified experimentally, the DPD is immune to the common-phase noise induced by an electro-optic phase modulator or by thermal disturbance within the interferometer. This signifies that the minimum-detectable differential phase can become 10(-8) rad/sqrt Hz if a 300 mW continuous wave laser is employed instead.     

One-step fabrication of carbon nanotubes decorated with graphitic nanoflakes for energy storage systems

We have used a bias-assisted microwave plasma chemical vapor deposition system to synthesize carbon nanotubes presenting graphitic nanoflakes, named coral-like carbon nanotubes, and well-aligned carbon nanotubes on carbon cloth substrates. Applying an external bias of -100 V led to the growth of well-aligned carbon nanotubes. In the absence of an external bias, the coral-like nanotubes presenting graphite nanoflakes were formed. The specific surface areas of the well-aligned and coral-like carbon nanotubes electrodes were 90.31 and 143.69 m2/g, respectively. In terms of energy storage, we estimated the capacitance of the coral-like carbon nanotube electrode to be ca. 194 F/g in an electrolyte of 1 M H2SO4. This value is almost double that of the well-aligned carbon nanotubes electrode (104 F/g), presumably because the presence of the carbon nanoflakes had a positive influence on the migration and adsorption of ions within the electrode. The fitting results indicated that the coral-like carbon nanotubes electrode behaved as a traditional electrochemical capacitor. Durability tests revealed that the coral-like carbon nanotube electrode was reliable, with a decay of 9% in capacitance over 1000 cycles.     

Write Disturbance Modeling and Testing for MRAM

The magnetic random access memory (MRAM) is considered one of the potential candidates that will replace current on-chip memories (RAM, EEPROM, and flash memory) in the future. The MRAM is fast and does not need a high supply voltage for read/write operations, and is compatible with the CMOS technology. It can also endure almost unlimited read/write cycles. These combined advantages of RAM and flash memory make it a potential choice for SOC. In this paper, we present the write disturbance fault (WDF) model for MRAM, i.e., a fault that affects the data stored in the MRAM cells due to excessive magnetic field during the write operation. We also construct the SPICE macro model for the magnetic tunneling junction (MTJ) device of the toggle MRAM to obtain circuit simulation results. We then present an MRAM fault simulator called RAMSES-M, based on which we derive the shortest test for the proposed WDF model. The test is shown to be better and more robust as compared with the conventional March C-test algorithm. We also present a March 17 N diagnosis algorithm for identifying WDF. A 1 Mb MRAM chip has been designed and fabricated using a CMOS-based 0.18-mum technology. The proposed WDF model is justified by chip measurement results, with the march test results reported. Finally, specific MRAM fault behavior and test issues are discussed.     

Microtube Array Membrane Encapsulated Cell Therapy: A Novel Platform Technology Solution for Treatment of Alzheimer’s Disease

Alzheimer’s disease is the most frequent form of dementia in aging population and is presently the world’s sixth largest cause of mortality. With the advancement of therapies, several solutions have been developed such as passive immunotherapy against these misfolded proteins, thereby resulting in the clearance. Within this segment, encapsulated cell therapy (ECT) solutions that utilize antibody releasing cells have been proposed with a multitude of techniques under development. Hence, in this study, we utilized our novel and patented Microtube Array Membranes (MTAMs) as an encapsulating platform system with anti-pTau antibody-secreting hybridoma cells to study the impact of it on Alzheimer’s disease. In vivo results revealed that in the water maze, the mice implanted with hybridoma cell MTAMs intracranially (IN) and subcutaneously (SC) showed improvement in the time spent the goal quadrant and escape latency. In passive avoidance, hybridoma cell loaded MTAMs (IN and SC) performed significantly well in step-through latency. At the end of treatment, animals with hybridoma cell loaded MTAMs had lower phosphorylated tau (pTau) expression than empty MTAMs had. Combining both experimental results unveiled that the clearance of phosphorylated tau might rescue the cognitive impairment associated with AD.     

Developments of metallic anodes with various compositions and surfaces for the microbial fuel cells

Factors that affect the power performance of microbial fuel cells (MFCs) are well known to be very complex because of their multidisciplinary character, especially with respect to the electrode. In this study, for the first time, specimens of different metallic materials with smooth and rough surfaces, including Cu-based alloys and porous Ni plates whose sintering temperature was in the range of 900 °C–1100 °C, were investigated with regard to their possible application as anodes in MFCs. The results show that MFCs equipped with a Cu–Ag alloy anode could produce a higher power performance with an open-circuit voltage of 0.65 V and a power density of 1141.69 mW m^?2 compared to the other anodes of Cu–Zn and Cu–Ni–Zn alloys. The reason is that the performances of anodes are proportional to the electrical conductivity of the various alloys. In addition, the porosity of the specimens is 20.3% for the Ni-1100 °C and 58.4% for the Ni-900 °C anode material. The conductivity of the anodes decreases with increasing porosity, which, in turn, will result in a lower power performance. Here, the Ni-1100 anode applied in MFCs displays a better performance with an open-circuit voltage of 0.56 V, a limiting current density of 3140 mA m^?2, and a corresponding maximum power density of 448 mW m^?2. The output power density could be maintained at 450 mW m^?2 after a test of 50 h.     

The effect of a finite distance source on an Applebaum array

The effect of the finite distance of the signal source on the performance of a far-field steering Applebaum type adaptive array is examined. The output signal-to-noise ratio (SNR) is expressed in terms of 1) the distance between the signal and the array center, 2) the input SNR, 3) the element number and locations, and 4) the signal direction. From that expression a rule of thumb is drawn to determine the distance between the signal source and the array center at which the degradation of the output SNR is 1 dB. That distance is in general much larger than the far-field range of a conventional beam forming array.     

Fluorescein and Poly(Ethylene Oxide) Hose Stream Additives for Improved Firefighting Effectiveness

A novel technique has been developed to accurately monitor levels of hose stream additives by adding a fluorescein tracer. A fluorescent agent system is proposed to control and monitor additives into hose streams. Fluorescent water streams also have the advantage of improved nighttime and low-light visibility.Poly(ethylene oxide) (PEO) was shown in the 1960s to be very effective in fire hose streams, providing dramatic increases in hose stream pressure, reach, and volume. As is discussed in this paper, however, PEO fell into disrepute for firefighting operations. A reexamination strongly indicates the inaccuracy of previous misperceptions and indicates that PEO deserves reconsideration as being potentially powerful for greatly enhanced petroleum, ordnance, high-rise and impeded access firefighting, in which increased stand-off distances are desirable.     

Performance of PLL Synchronized Optical PPM Communication Systems

Receiver timing synchronization of an optical PPM communication system can be achieved using a phase-locked loop (PLL) if the photodetector output is properly processed. The synchronization performance is shown to improve with increasing signal power and decreasing loop bandwidth. The bit error rate performance of the PLL synchronized PPM system is analyzed and compared to that of the perfectly synchronized system. It is shown that the increase in signal power needed to compensate for the imperfect synchronization is small (less than 0.1 dB) for loop bandwidths less than 0.1 percent of the slot frequency.     

Donation Center Location Problem

We introduce and study the donation center location problem, which has an additional application in network testing and may also be of independent interest as a general graph-theoretic problem. Given a set of agents and a set of centers, where agents have preferences over centers and centers have capacities, the goal is to open a subset of centers and to assign a maximum-sized subset of agents to their most-preferred opened centers, while respecting the capacity constraints. We prove that in general, the problem is hard to approximate within n ^1/2?? for any ?>0. In view of this, we investigate two special cases. In one, every agent has a bounded number of centers on its preference list, and in the other, all preferences are induced by a line-metric. We present constant-factor approximation algorithms for the former and exact polynomial-time algorithms for the latter.