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Ji Q.,Inspur Group
Lecture Notes in Computer Science (including subseries Lecture Notes in Artificial Intelligence and Lecture Notes in Bioinformatics) | Year: 2015

Quenched disorder (QD) and surface field are two key factors in nano-confinement researches. Despite decades of development, distinguishing the two factors is still challenging. To explore this issue, liquid crystals (LCs) confined in both smooth and rough cylinders are simulated and compared with the bulk LCs. The rough cylinders are aperiodical and produced firstly via randomly spherical indentation. Results show that QD reduces the order of orientation and translation, lessens the anisotropy of diffusion and shortens the rotational correlation time of the confined LCs with respect to the surface field. The intensity of the QD effects depends on the magnitude of the roughness of cylinders. In addition, the anisotropic diffusion of LCs exhibits a circular pattern when LCs system are cooled from the isotropic phase to the smectic phase. The simulated anisotropic diffusion validates the affine transformation model for the Bulk system in the isotropic and nematic phases. The model, however, underestimates the anisotropy of the confined systems. These results are helpful to develop physical models and explain experimental phenomena for confinement researches. © Springer International Publishing Switzerland 2015. Source


Ho C.K.,Institute of Microelectronics, Singapore | Cheong J.H.,Institute of Microelectronics, Singapore | Lee J.,Institute of Microelectronics, Singapore | Kulkarni V.,Institute of Microelectronics, Singapore | And 3 more authors.
IEEE Transactions on Microwave Theory and Techniques | Year: 2014

With the growing number of wearable devices and applications, there is an increasing need for a flexible body channel communication (BCC) system that supports both scalable data rate and low power operation. In this paper, a highly flexible frequency-selective digital transmission (FSDT) transmitter that supports both data scalability and low power operation with the aid of two novel implementation methods is presented. In an FSDT system, data rate is limited by the number of Walsh spreading codes available for use in the optimal body channel band of 40-80 MHz. The first method overcomes this limitation by applying multi-level baseband coding scheme to a carrierless FSDT system to enhance the bandwidth efficiency and to support a data rate of 60 Mb/s within a 40-MHz bandwidth. The proposed multi-level coded FSDT system achieves six times higher data rate as compared to other BCC systems. The second novel implementation method lies in the use of harmonic frequencies of a Walsh encoded FSDT system that allows the BCC system to operate in the optimal channel bandwidth between 40-80 MHz with half the clock frequency. Halving the clock frequency results in a power consumption reduction of 32%. The transmitter was fabricated in a 65-nm CMOS process. It occupies a core area of 0.24×, 0.3 mm2. When operating under a 60-Mb/s data-rate mode, the transmitter consumes 1.85 mW and it consumes only 1.26 mW when operating under a 5-Mb/s data-rate mode. © 2014 IEEE. Source


Liu L.-N.,Shandong Normal University | Yu Z.-L.,Inspur Group
Proceedings - 2012 4th International Conference on Multimedia and Security, MINES 2012 | Year: 2012

Knowledge is power and this adage conveys the importance of knowledge immutably, in the time of knowledge explosion, the way to acquire the necessary knowledge which enterprises or organizations need efficiently from the ocean of knowledge becomes the main problem, which the era of knowledge economy should face. This paper proposed an improved knowledge push method based on semantic similarity. We can take the initiative to push the knowledge to client what they interest and save the time required to query interesting knowledge from the vast resources. The experimental results show that our method has higher accuracy compared to the typical similarity calculation method. © 2012 IEEE. Source


Bonnaud P.A.,Massachusetts Institute of Technology | Ji Q.,Massachusetts Institute of Technology | Ji Q.,Inspur Group | Coasne B.,Charles Gerhardt Institute | And 3 more authors.
Langmuir | Year: 2012

Water within pores of cementitious materials plays a crucial role in the damage processes of cement pastes, particularly in the binding material comprising calcium-silicate-hydrates (C-S-H). Here, we employed Grand Canonical Monte Carlo simulations to investigate the properties of water confined at ambient temperature within and between C-S-H nanoparticles or "grains" as a function of the relative humidity (%RH). We address the effect of water on the cohesion of cement pastes by computing fluid internal pressures within and between grains as a function of %RH and intergranular separation distance, from 1 to 10 Å. We found that, within a C-S-H grain and between C-S-H grains, pores are completely filled with water for %RH larger than 20%. While the cohesion of the cement paste is mainly driven by the calcium ions in the C-S-H, water facilitates a disjoining behavior inside a C-S-H grain. Between C-S-H grains, confined water diminishes or enhances the cohesion of the material depending on the intergranular distance. At very low %RH, the loss of water increases the cohesion within a C-S-H grain and reduces the cohesion between C-S-H grains. These findings provide insights into the behavior of C-S-H in dry or high-temperature environments, with a loss of cohesion between C-S-H grains due to the loss of water content. Such quantification provides the necessary baseline to understand cement paste damaging upon extreme thermal, mechanical, and salt-rich environments. © 2012 American Chemical Society. Source


Kulkarni V.V.,Institute of Microelectronics, Singapore | Lee J.,Institute of Microelectronics, Singapore | Zhou J.,Institute of Microelectronics, Singapore | Ho C.K.,Institute of Microelectronics, Singapore | And 5 more authors.
IEEE Transactions on Microwave Theory and Techniques | Year: 2014

Body channel communication (BCC) integrated circuits for emerging wireless body area network multimedia applications call for the need of high-speed inter-device data communication at ultra-low-power consumption and smaller device footprint. In this paper, a novel low-power injection-locking-based clock-recovery circuit (CRC) is proposed for BCC transceivers that employ multilevel direct digital signaling for high data rates. The CRC utilizes transition detection for generating pulses from transmitted digital data and injects them directly into the VCO to recover the clock. The pulse-based direct injection-locking architecture achieves instantaneous clock recovery from random multilevel data with a sensitivity of up to-43 dBm, and eliminates the need for a reference crystal used in conventional phase-locked-loop-based CRC circuits. Measured results verify that the proposed CRC achieves clock recovery for two-and three-level signals for data rates up to 160 Mb/s. Implemented in 65-nm CMOS technology, the CRC consumes 0.84 mW with a footprint of 0.122. © 2014 IEEE. Source

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