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991.
992.
Sam Chau Duong Hiroshi Kinjo Eiho Uezato Tetsuhiko Yamamoto 《IEEJ Transactions on Electrical and Electronic Engineering》2011,6(3):236-244
It is well known that the class of nonholonomic systems cannot be asymptotically stabilized by continuous static state feedback controls. It has been reported that the so‐called direct gradient descent control (DGDC) is able to stabilize nonholonomic systems. This article attempts to improve the performance of the DGDC by using neural network (NN) and particle swarm optimization (PSO). A control method is proposed by embedding an NN into the control law derived by the original DGDC. PSO is employed in order to search globally the parameters of the controller without requiring a redesign process of the parameters. To verify the method, the control problems of two typical nonholonomic systems, one being a wheeled mobile robot and the other a rotary crane system, are considered under constraints applied to the systems. Comparative performance tests are carried out, showing that the proposed approach outperforms the original method and a neurocontroller. Also, simulations show that the proposed method is able to control the systems effectively under the given constraints without the need of the redesign process. © 2011 Institute of Electrical Engineers of Japan. Published by John Wiley & Sons, Inc. 相似文献
993.
Fallen timber (logs, large boughs) is recognized as having high ecological significance on forest floors. In floodplain forests, fallen timber potentially has even higher value for supporting biodiversity than upland forests because distinct faunal elements use the timber in the flooded and unflooded conditions. Invertebrates were sampled in logs of the river red gum (Eucalyptus camaldulensis Dehnh.) that had been inundated 1 year earlier and compared with invertebrates in logs that had not been inundated for many years. The invertebrate fauna in river red gum logs was relatively depauperate, probably reflecting the variable, sub‐humid conditions on the floodplain. The abundance and taxon richness of invertebrates was highest in logs with greater structural complexity and heterogeneity due to extensive decay. Recent inundation slightly reduced taxon richness. The succession of log‐dwelling invertebrates was tracked though transitions between terrestrial fauna and aquatic fauna in a spring/summer flood cycle. Transition between the two faunae was rapid. Logs were colonized by aquatic invertebrates within 2 weeks of immersion by floodwaters and recolonized by terrestrial invertebrates within 4 weeks of emersion. This faunal dynamism highlights the need to consider the entire flood cycle in decisions about the management of fallen timber on floodplains for biodiversity. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
994.
Jeong Hyun Yeum Jin Woo Kwak Sung Soo Han Sam Soo Kim Byung Chul Ji Seok Kyun Noh Won Seok Lyoo 《应用聚合物科学杂志》2004,94(4):1435-1439
To precisely identify the effect of blend ratios of syndiotacticity‐rich poly(vinyl alcohol) (s‐PVA)/atactic PVA (a‐PVA) on the water stability of s‐PVA/a‐PVA/iodine complex blend films, we prepared two PVAs with similar number‐averaged degrees of polymerization of 4000 and degrees of saponification of 99.9% and with different syndiotactic diad contents of 58.5 and 53.5%, respectively. The desorption behavior of iodine in s‐PVA/a‐PVA/iodine complex films in water was investigated in terms of the solubility of s‐PVA/a‐PVA blend films in water. The degree of solubility of s‐PVA/a‐PVA blend films with s‐PVA content over 50% in water at 70°C was limited to about 10–20%, whereas that of s‐PVA/a‐PVA blend films with s‐PVA content of 10% was 85% under the same conditions. The degree of iodine desorption of complex blend films decreased with increasing s‐PVA content. The degree of iodine desorption of s‐PVA/a‐PVA drawn film with s‐PVA content of 90% was limited to 7%, regardless of the soaking temperature from 30 to 70°C. The desorption of iodine in water was strongly affected by the dissolution of blends. Moreover, the stability of iodine in the drawn s‐PVA/a‐PVA/iodine blend films in hot water was far superior to that of the undrawn film. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 94: 1435–1439, 2004 相似文献
995.
Kanagavel Deepankumar Minsu Shon Saravanan Prabhu Nadarajan Giyoung Shin Sam Mathew Niraikulam Ayyadurai Byung‐Gee Kim Sei‐Hyun Choi Sang‐Hyeup Lee Hyungdon Yun 《Advanced Synthesis u0026amp; Catalysis》2014,356(5):993-998
Here, we have utilized the incorporation of non‐canonical amino acids as a tool kit to improve enzyme properties for organic synthesis applications. The global incorporation of 3‐fluorotyrosine (FY) into ω‐transaminase (ω‐TA) to give ω‐TA[FY] enhanced the thermostability and organic solvent tolerance without altering substrate specificity and enantioselectivity. Moreover, ω‐TA[FY] was able to completely convert 25 mM of acetophenone into (S)‐1‐phenylethylamine (ee>99%) in the presence of 20% DMSO (v/v) which is ∼2‐fold higher when compared to wild‐type ω‐TA.
996.
The first reported use of two‐dimensional mesh thermoplastic fibers in an epoxy matrix for mendable composites is presented, yielding 100% restoration of GIC, failure energy, and peak loads over repeated damage‐healing cycles. SEM imaging and EDS mapping showed different surface structures between CFRPp and CFRPf and confirmed strength recoveries were attained by delivery of EMAA to the fracture plane which enabled the fractured surfaces to rebind after heating to 150 °C for 30 min.
997.
Linear low‐density polyethylene/soya powder blends were prepared by using an internal mixer at 150°C. The soya powder content ranged from 5 to 40 wt %. Epoxidized natural rubber with 50 mol % epoxidation (ENR 50) was added as a compatibilizer. The blends were irradiated by electron beam (EB) at a constant dose of 30 kGy. The changes in gel fraction, tensile properties, morphological and thermal properties of the samples were investigated. The gel content increased after EB irradiation. However, the increment of gel content was hindered by increasing soya powder content. The tensile strength and Young's modulus of the blends were increased by EB whereas the elongation at break decreased. The tensile fracture surface also support the reduction of elongation at break by EB irradiation. Further analysis on the irradiated blends using Fourier transform infrared spectra indicated an increase of oxygenated product after undergoing EB irradiation. The differential scanning calorimetry result indicated that the melting temperature of the blends decreased after EB irradiation whereas the crystallinity increased. EB irradiation also enhanced the thermal stability of the blends as indicated by thermogravimetric analysis. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011 相似文献
998.
Cellulose filters were dipped and padded with m‐aramid dissolved in N,N‐dimethylacetamide followed by coagulation in distilled water. The coated filters were then chlorinated in a hypochlorite solution. The liquid permeability of the m‐aramid‐coated cellulose filters was examined. The resulting chlorinated and unchlorinated filters were assessed for their ability to disinfect contaminated water. The chlorinated m‐aramid‐coated cellulose filter produced 5 log reductions of Escherichia coli and Staphylococcus aureus, which was much higher than that observed on the unchlorinated m‐aramid‐coated cellulose filter. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
999.
A commercial m‐aramid as N‐halamine precursor has been coated onto polyethylene terephthalate (PET) fabric surface by pad‐dry‐curing process. The process is accomplished by padding the scoured PET fabric through the homogeneous m‐aramid solution, drying at 150°C for 3 min, and curing at 230°C for 3 min. The PET surface coated with m‐aramid was characterized using fourier transform infrared‐attenuated total reflection (FTIR‐ATR) spectroscopy, X‐ray photoelectron spectroscopy (XPS), and scanning electron microscopy (SEM). FTIR exhibits new bands in the 1645 and 1524 cm?1 regions as characteristic of m‐aramid bands, which indicate the PET fabric coated with m‐aramid. XPS results show a distinguishable peak at binding energy 398.7 eV, which confirms the nitrogen atom of m‐aramid on the PET surface. In addition, SEM image shows a layer of coating onto the PET surfaces, which demonstrates the presence of m‐aramid coating on the surface of the PET. After exposure to dilute sodium hypochlorite solution, exhibition of antimicrobial activity on the coated PET is attributed to the conversion of N‐halamine moieties from the N‐halamine precursor. The chlorinated PET showed high antimicrobial activity against Gram‐negative and Gram‐positive bacteria. The chlorinated PET coated with 10% m‐aramid exhibited about 6 log reductions of S. aureus and E. coli O157:H7 at a contact time of 10 and 30 min, respectively. Furthermore, the antimicrobial activity was durable and rechargeable after 25 wash cycles. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009 相似文献
1000.
深圳度高从2002年9月推出第一台高保真DVD＆HDCD播放器以来,凭借着优秀的设计制作和出色的表现而一直蜚声国内Hi-Fi界。度高的HDP-17、HDP-15MKII和HDP-19等DVD播放器曾多次获得国内音响大奖,其音质表现也得到了广大的音响爱好者和专家的一致认同。笔者虽然对于度高是久闻其名,但一直无缘亲身体验,颇感遗憾。近期,在度高向市场推出了其最新的高保真DVD播放器——HDV-16后,我们立即拿来了一台进行试用。 相似文献