Thermoelectric Properties of Multifilled Skutterudites with La as the Main Filler

Bulk multifilled n- and p-type skutterudites with La as the main filler were fabricated using the spark plasma sintering (SPS) method. The thermoelectric properties and thermal stability of these skutterudites were investigated. It was found that the interactions among the filling atoms also play a vital role in reducing the lattice thermal conductivity of the multifilled skutterudites. ZT = 0.76 for p-type La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ and ZT = 1.0 for n-type La_0.3Ca_0.1Al_0.1Ga_0.1In_0.2Co_3.75Fe_0.25Sb₁₂ skutterudites have been achieved. Furthermore, the differential scanning calorimetry (DSC) results show that there is no skutterudite phase decomposition till 750°C for the La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ sample. The thermal stability of the La_0.8Ba_0.01Ga_0.1Ti_0.1Fe₃CoSb₁₂ skutterudite is greatly improved. Using the developed multifilled skutterudites, the fabricated module with size of 50 mm × 50 mm × 7.6 mm possesses maximum output power of 32 W under the condition of hot/cold sides = 600°C/50°C.     

Analysis of Frequency Selective Surfaces at Millimeter Wave Band Using the Hertz Vector Potential Method

In this work, the Hertz vector potential method was used to obtain the dyadic Green’s function components for frequency selective surfaces (FSS) on an anisotropic layer. The considered structures are composed by periodic arrays of conducting crossed dipole and rectangular patch elements. Results of reflected power were obtained by using the moment method. Curves for the reflected power versus frequency are presented as function of the structural parameters, assuming x, y, and z orientation for the optical axis in the anisotropic substrate.     

Dual-band circularly polarized equilateral triangular-patch array antenna for mobile satellite communications

The Japan Aerospace Exploration Agency will launch the Engineering Test Satellite VIII (ETS-VIII) in 2006 to support the next generation of mobile satellite communications covering the area of Japan (beam coverage El=38/spl deg/ to 58/spl deg/). In this paper, a satellite-tracking left-handed circularly polarized triangular-patch array antenna is developed for ground applications. The targeted minimum gain of the antenna is set to 5 dBic at the central elevation angle (El=48/spl deg/), in the Tokyo area, for applications using data transfer of around a hundred kbps. The antenna is composed of three equilateral triangular patches for both reception and transmission units operating at 2.50 and 2.65 GHz frequency bands, respectively. The antenna was simulated by method of moments (MoM) analysis, and measurement of the fabricated antenna was performed to confirm the simulation results. The measurement results show that the frequency characteristics and the 5-dBic gain coverage in the conical-cut plane of the fabricated antenna satisfy the specifications for ETS-VIII. A prototype of the proposed antenna system is employed in outdoor experiments using a pseudosatellite and shows good performance from El=38/spl deg/ to 58/spl deg/.     

Negative giant surface potential of vacuum-evaporated tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)3] film

Negative giant surface potential was realized in a vacuum-evaporated film of tris(7-propyl-8-hydroxyquinolinolato) aluminum(III) [Al(7-Prq)₃]. Electroabsorption response of the film presented an inverted polarity to that of tris(8-hydroxyquinolinolato) aluminum (Alq₃), suggesting opposite noncentrosymmetry of molecular orientation. Asymmetric dice model with molecular geometric effect has been proposed, and propyl substitution at 7 position of the ligands was indicated to affects the molecular posture on the surface to invert the polarity of noncentrosymmetry. Our results opened a new possibility of controlling molecular orientation in a film for device applications.     

A single-power-supply 10-b video BiCMOS sample-and-hold IC

A +5-V single-power-supply 10-b video BiCMOS sample-and-hold IC is described. Video speed, low power, and 10-b accuracy sample-and-hold operation have been achieved using a complementary connected buffer format sample switch. A high-speed p-n-p transistor used in the sample switch is formed by a combination of n-p-n and PMOS transistors. The sample-and-hold operation is accomplished by feeding back the hold capacitor voltage to the sample switch inputs, so that the inputs transfer symmetrically for the hold capacitor voltage at any input level. The sample-and-hold IC has been implemented in 1.2-μm BiCMOS technology and evaluated. The following results have been obtained: 185-MHz 3-dB bandwidth at 22-pF hold capacitor, 63-dB signal-to-noise ratio at 8-MHz full-scale input, 20-ns acquisition time at 1-V step input, 15-ns switch setting time, and 0.1% linearity error. Power dissipation is 150 mW     

High-throughput analysis of multispectral images of breast cancer tissue.

Statistical analysis of genetic changes within cell nuclei that are far from the primary tumor would help determine whether such changes have occurred prior to tumor invasion. To determine whether the gene amplification in cells is morphologically and/or genetically related to the primary tumor requires quantitative evaluation of a large number of cell nuclei from continuous meaningful structures such as milk-ducts, tumors, etc., located relatively far from the primary tumor. To address this issue, we have designed an integrated image analysis software system for high-throughput segmentation of nuclei. Filters such as Beltrami flow-based reaction-diffusion, directional diffusion, etc., were used to pre-process the images resulting in a better segmentation. The accurate shape of the segmented nucleus was recovered using an iterative "shrink-wrap" operation. The study of two cases of ductal carcinoma in situ in breast tissue supports the biological observation regarding the existence of a preferential intraductal invasion, and therefore a common origin, between the primary tumor and the gene amplification in the cell-nuclei lining the ductal structures in the breast.     

A Multi-user Receiver for Inter-Cell Interference Reduction in LTE PUCCH Signaling

In 3rd generation partnership project (3GPP) long term evolution (LTE) systems, when no resources has been assigned in the uplink to a given user equipment (UE), the control information associated with layers 1 and 2 in the protocol stack is conveyed back to the base station through the so-called physical uplink control channel (PUCCH). In PUCCH, the data streams transmitted by multiple UEs are multiplexed in the time-domain and in the frequency-domain with the aid of spreading codes. Although the spreading codes associated with UEs within the same cell can be assumed to be orthogonal, the presence of inter-cell interference (ICI) in multi-cell scenarios severely limits receiver performance. In particular, the Format 1 of PUCCH, which is associated with the transmission of hybrid automatic repeat request acknowledgements (ACK/NACK) and scheduling requests, has a major impact on system performance, since an incorrectly decoded ACK/NACK message may introduce significant delay in data transmission. In this contribution, we propose a new multi-user receiver for ICI reduction in PUCCH LTE that operates both in cooperative and non-cooperative multi-cell architectures. The proposed receiver relies on a constrained tensor modeling of the received signal in PUCCH signaling, and affords an iterative joint channel estimation and symbol detection by simultaneously exploiting the energy of the data symbols and the pilot tones present in PUCCH. The formulation of the proposed algebraic receiver model incorporates symbol-basis hopping and slot-basis hopping signaling schemes, which are interference randomization techniques existing in the 3GPP specifications of LTE system. Computer simulation results show the remarkable performance gains of the proposed receiver compared to the conventional time-frequency decorrelator based receiver.     

Ultrafast reflective optical Kerr demultiplexer using polarisation rotation mirror

A novel all-optical switching scheme in a reflective mode is proposed and its stable 60 Gbit/s operation at 1.307 mu m demonstrated. The scheme uses a 90 degrees polarisation rotation on reflection to compensate for birefringence phase turbulence in the Kerr media.<>     

Spatiotemporal Magnetocaloric Microenvironment for Guiding the Fate of Biodegradable Polymer Implants

The degradation behavior of implants is significantly important for bone repair. However, it is still unprocurable to spatiotemporally regulate the degradation of the implants to match bone ingrowth. In this paper, a magneto-controlled biodegradation model is established to explore the degradation behavior of magnetic scaffolds in a magnetothermal microenvironment generated by an alternating magnetic field (AMF). The results demonstrate that the scaffolds can be heated by magnetic nanoparticles (NPs) under AMF, which dramatically accelerated scaffold degradation. Especially, magnetic NPs modified by oleic acid with a better interface compatibility exhibit a greater heating efficiency to further facilitate the degradation. Furthermore, the molecular dynamics simulations reveal that the enhanced motion correlation between magnetic NPs and polymer matrix can accelerate the energy transfer. As a proof-of-concept, the feasibility of magneto-controlled degradation for implants is demonstrated, and an optimizing strategy for better heating efficiency of nanomaterials is provided, which may have great instructive significance for clinical medicine.     

Construction of baselines for VoIP traffic management on open MANs

In the last century, owing to the constant evolution of technologies telecommunication networks have become increasingly robust, being able to support multiple services. These services are part of the heterogeneous network traffic that can be carried through the Internet. Many of these services, including VoIP, are latency sensitive. In other words, this means that their quality depends directly on the network quality of service. Since users tend to become more sensitive with the instability and unavailability of the network, it is important to improve traffic management. A particular type of data that could be used to improve VoIP traffic management is the Internet Protocol Detail Record (IPDR). IPDRs are tickets created by all VoIP call attempts which contain a group of information related to the call history. Because of its full range of information, IPDRs can be used to create VoIP traffic baselines. This paper presents the development of baselines based on IPDRs to support VoIP traffic management in open‐access Metropolitan Area Networks (MAN). Copyright © 2013 John Wiley & Sons, Ltd.