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排序方式: 共有9817条查询结果,搜索用时 15 毫秒
51.
Siwoo Park Ki-Choon Choi Minghao Fang Yung Chul Lim Young-Mi Jeon Jeong-Chae Lee 《Food science and biotechnology》2011,20(4):1125-1131
This study used in vitro and in vivo experimental models to investigate the anti-inflammatory potential of the butanol fraction of red bean ethanol extract (BF-RBEE), which contains the biologically active molecule catechin-7-β-d-glucopyranoside. Treatment with BF-RBEE inhibited nitric oxide production in lipopolysaccharide (LPS)-stimulated macrophages through suppression of extracellular signalregulated kinase and IκBα activation. In an in vivo murine sepsis model, oral administration of BF-RBEE improved mouse survival. Specifically, the survival rate of mice injected with LPS was 0 and 40% in ICR and BALB/c mice, respectively, whereas the survival of mice co-treated with BF-RBEE was 100% in both mouse types. This increase in survival with the BF-RBEE administration was correlated with decreased tumor-necrosis factor-α and interferon-γ and increased interleukin-10. Oral administration of BF-RBEE also inhibited total and ovalbumin-specific IgE production in experimental mice. These results suggest the possible usefulness of red beans in the treatment of inflammatory diseases. 相似文献
52.
53.
Yi Wu Teng Joon Lim 《Wireless Communications, IEEE Transactions on》2004,3(2):348-352
In this letter, we study differentially modulated, iteratively decoded CDMA. The iterative multiuser receiver proposed consists of an additional soft-input soft-output (SISO) differential decoder, when compared to turbo multiuser detectors for absolutely modulated systems. Algorithms for iterative decoding with and without phase information at the receiver are developed. The resulting turbo receivers with differential modulation outperform coherent receivers with absolute modulation at moderate to high signal to noise ratios due to the interleaver gain associated with recursive inner encoders in serially concatenated encoding structures. 相似文献
54.
Wan-Seon Lim Dong-Wook Kim Young-Joo Suh 《Wireless Communications, IEEE Transactions on》2010,9(1):66-71
In this paper, we propose a new MAC protocol, called proxy relay-enabled MAC (PR-MAC), to improve the capacity of multi-rate WLANs. PR-MAC introduces a new entity called Proxy Relay Point (PRP), which serves as a relay between the AP and stations. The cooperation of the AP with PRP replaces direct transmissions for low-rate stations with fast two-hop transmissions while the stations think that they communicate directly with the AP. Our experiment and simulation results showed that PR-MAC can significantly improve the throughput of legacy stations without any modification on the MAC operation of the stations. 相似文献
55.
In this paper, we consider the problem of how to represent the locations of Internet hosts in a Cartesian coordinate system to facilitate estimation of network distances among arbitrary Internet hosts. We envision an infrastructure that consists of beacon nodes and provides the service of estimating network distance between pairs of hosts without direct delay measurement. We show that the principal component analysis (PCA) technique can effectively extract topological information from delay measurements between beacon hosts. Based on PCA, we devise a transformation method that projects the raw distance space into a new coordinate system of (much) smaller dimensions. The transformation retains as much topological information as possible and yet enables end hosts to determine their coordinates in the coordinate system. The resulting new coordinate system is termed as the Internet Coordinate System (ICS). As compared to existing work (e.g., IDMaps and GNP), ICS incurs smaller computation overhead in calculating the coordinates of hosts and smaller measurement overhead (required for end hosts to measure their distances to beacon hosts). Finally, we show via experiments with both real-life and synthetic data sets that ICS makes robust and accurate estimates of network distances, incurs little computational overhead, and its performance is not susceptible to the number of beacon nodes (as long as it exceeds a certain threshold) and the network topology. 相似文献
56.
Ya Jun Yu Yong Ching Lim 《IEEE transactions on circuits and systems. I, Regular papers》2007,54(10):2330-2338
In this paper, a novel optimization technique is proposed to optimize filter coefficients of linear phase finite-impulse response (FIR) filter to share common subexpressions within and among coefficients. Existing approaches of common subexpression elimination optimize digital filters in two stages: first, an FIR filter is designed in a discrete space such as finite wordlength space or signed power-of-two (SPT) space to meet a given specification; in the second stage, an optimization algorithm is applied on the discrete coefficients to find and eliminate the common subexpressions. Such a two-stage optimization technique suffers from the problem that the search space in the second stage is limited by the finite wordlength or SPT coefficients obtained in the first stage optimization. The new proposed algorithm overcomes this problem by optimizing the filter coefficients directly in subexpression space for a given specification. Numerical examples of benchmark filters show that the required number of adders obtained using the proposed algorithm is much less than those obtained using two-stage optimization approaches. 相似文献
57.
Liang Yan I-Ming Chen Chee Kian Lim Guilin Yang Wei Lin Kok-Meng Lee 《Mechatronics, IEEE/ASME Transactions on》2008,13(2):239-248
This paper has proposed a 3-DOF spherical actuator consisting of a ball-shaped rotor with a full circle of permanent- magnet (PM) poles and a spherical-shell-like stator with two layers of circumferential air-core coils. One key feature of this design is the parametrization of PM and coil poles. Based on the torque model of the PM spherical actuator, the relationship between poles' parameters and torque output can be demonstrated. As a result, the actuator design aiming at achieving maximum torque output can be carried out from the relationships. Another advantage of this spherical actuator is its singularity-free workspace, which is verified with the actuator torque model and condition numbers. 相似文献
58.
A device able to electrokinetically concentrate cationic samples has many potential medical and industrial applications, but until now has remained undeveloped due to the lack of a commercial anion-permselective material leading to a prohibitively complex fabrication procedure. Herein, a novel multiscale-porous anion exchange membrane (MP-AEM) that enables the convenient and scalable electrokinetic concentration of cationic species is proposed. A mechanically enhanced multiscale-porous structure with a solid framework is realized by adopting polyester resin as an additive to overcome the intrinsic limitations of the AEM material. The scalable MP-AEM-embedded electrokinetic concentrator is devised based on the peculiar properties of the MP-AEM that for allow both ion and fluid transport. With the MP-AEM, the concentrator is fabricated in a highly streamlined manner consisting only of a simple insertion and assembly. The concentration performance of the MP-AEM-embedded electrokinetic concentrator is demonstrated with a positively charged fluorescent dye and a fluorescein-labeled protein, and the results show enrichment factors of 250 and 500, respectively. The MP-AEM makes cationic electrokinetic concentration more accessible and scalable, thereby enabling further progress in a wide range of fields. 相似文献
59.
Younggeun Lee Jinhyeong Kwon Jaemook Lim Wooseop Shin Sewoong Park Eunseung Hwang Jaeho Shin Hyunmin Cho Jinwook Jung Hyun-Jong Kim Seungyong Han Habeom Lee Yong Son Cheol Woo Ha Prem Prabhakaran Junyeob Yeo Seung Hwan Ko Sukjoon Hong 《Advanced functional materials》2021,31(1):2006854
Structural coloration is closely related to the progress of innovative optoelectronic applications, but the absence of direct, on-demand, and rewritable coloration schemes has impeded advances in the relevant area, particularly including the development of customized, reprogrammable optoelectronic devices. To overcome these limitations, a digital laser micropainting technique, based on controlled thin-film interference, is proposed through direct growth of the absorbing metal oxide layer on a metallic reflector in the solution environment via a laser. A continuous-wave laser simultaneously performs two functions—a photothermal reaction for site-selective metal oxide layer growth and in situ real-time monitoring of its thickness—while the reflection spectrum is tuned in a broad visible spectrum according to the laser fluence. The scalability and controllability of the proposed scheme is verified by laser-printed painting, while altering the thickness via supplementary irradiation of the identical laser in the homogeneous and heterogeneous solutions facilitates the modification of the original coloration. Finally, the proof-of-concept bolometer device verifies that specific wavelength-dependent photoresponsivity can be assigned, erased, and reassigned by the successive application of the proposed digital laser micropainting technique, which substantiates its potential to offer a new route for reprogrammable optoelectronic applications. 相似文献
60.
Seok-In Na Ga-Young Ha Dae-Seob Han Seok-Soon Kim Ja-Yeon Kim Jae-Hong Lim Dong-Joon Kim Kyeong-Ik Min Seong-Ju Park 《Photonics Technology Letters, IEEE》2006,18(14):1512-1514
The selective wet etching of a p-GaN layer by using a solution of KOH in ethylene glycol (KE) was studied to enhance the optical and electrical performance of the GaN-based light-emitting diodes (LEDs). The surface of the p-GaN, which was selectively etched in the KE solution, showed hexagonal-shaped etch pits. The light-output power of etched LEDs was improved by 29.4% compared to that of the nonetched LED. This improvement was attributed to the increase in the probability of photons to escape due to the increased surface area of textured surface and the reduction in contact resistance of the ohmic layer resulting from the increased contact area and hole concentration on the textured p-GaN. The reverse leakage current of the LED was also greatly decreased due to the surface passivation and the removal of defective regions from the p-GaN. 相似文献