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41.
Ananda Sankar Kundu Oishee Mazumder Prasanna Kumar Lenka Subhasis Bhaumik 《Journal of Intelligent and Robotic Systems》2018,91(3-4):529-541
This paper presents a hand gesture based control of an omnidirectional wheelchair using inertial measurement unit (IMU) and myoelectric units as wearable sensors. Seven common gestures are recognized and classified using shape based feature extraction and Dendogram Support Vector Machine (DSVM) classifier. The dynamic gestures are mapped to the omnidirectional motion commands to navigate the wheelchair. A single IMU is used to measure the wrist tilt angle and acceleration in three axis. EMG signals are extracted from two forearm muscles namely Extensor Carpi Radialis and Flexor Carpi Radialis and processed to provide Root Mean Square (RMS) signal. Initiation and termination of dynamic activities are based on autonomous identification of static to dynamic or dynamic to static transition by setting static thresholds on processed IMU and myoelectric sensor data. Classification involves recognizing the activity pattern based on periodic shape of trajectories of the triaxial wrist tilt angle and EMG-RMS from the two selected muscles. Second order Polynomial coefficients extracted from the sensor trajectory templates during specific dynamic activity cycles are used as features to classify dynamic activities. Classification algorithm and real time navigation of the wheelchair using the proposed algorithm has been tested by five healthy subjects. Classification accuracy of 94% was achieved by DSVM classifier on ‘k’ fold cross validation data of 5 users. Classification accuracy while operating the wheelchair was 90.5%. 相似文献
42.
The effect of annealing on vertically aligned TiO2 NWs deposited by glancing angle deposition (GLAD) method on Si substrate using pressed and sintered TiO2 pellets as source material is studied.The FE-SEM images reveal the retention of vertically aligned NWs on Si substrate after annealing process.The EDS analysis of TiO2 NWs sample annealed at 600℃ in air for 1 h shows the higher weight percentage ratio of~2.6(i.e.,72.27% oxygen and 27.73% titanium).The XRD pattern reveals that the polycrystalline nature of anatase TiO2 dominates the annealed NWs sample.The electrical characteristics of Al/TiO2-NWs/TiO2-TF/p-Si (NW device) and Al/TiO2-TF/p-Si (TF device) based on annealed samples are compared.It is riveting to observe a lower leakage current of~1.32×10-7 A/cm2 at+1 V with interface trap density of~6.71×1011 eV-1cm-2 in NW device compared to~2.23×10-7 A/cm2 in TF device.The dominant leakage mechanism is investigated to be generally Schottky emission;however Poole-Frenkel emission also takes place during high reverse bias beyond 4 V for NWs and 3 V for TF device. 相似文献
43.
An enhancement mode p-GaN gate AlGaN/GaN HEMT is proposed and a physics based virtual source charge model with Landauer approach for electron transport has been developed using Verilog-A and simulated using Cadence Spectre, in order to predict device characteristics such as threshold voltage, drain current and gate capacitance. The drain current model incorporates important physical effects such as velocity saturation, short channel effects like DIBL (drain induced barrier lowering), channel length modulation (CLM), and mobility degradation due to self-heating. The predicted Id-Vds, Id-Vgs, and C-V characteristics show an excellent agreement with the experimental data for both drain current and capacitance which validate the model. The developed model was then utilized to design and simulate a single-pole single-throw (SPST) RF switch. 相似文献
44.
Identification of clay minerals based on chemometric analysis of measured infrared (IR) spectra was suggested. IR spectra were collected using the diffuse reflection technique. Discriminant analysis and principal component analysis were used as chemometric methods. Four statistical models were created for separation and identification of clay minerals. More than 50 samples of various clay mineral standards from different localities were used for the creation of statistical models. The results of this study confirm that the discriminant analysis of IR spectra of clay minerals could provide a powerful tool for identification of clay minerals. Differentiation of muscovite from illite and identification of mixed structures of illite-smectite were achieved. 相似文献
45.
Artificial shortage of surface water: how can water demand management mitigate the scarcity problem? 下载免费PDF全文
Water demand management stresses the crucial roles of water user motivations in balancing actual water availability and competing human needs. This paper shows how the absence of such motivations influences artificial water scarcity, even in resource‐abundant countries, and how slight modifications to economic instruments (surface water charges in particular) might solve the problem. Data from the Czech Republic are used to illustrate the rationale behind the artificial scarcity problem and its solution. A model with feedback based on historical surface water abstraction data is built to simulate the impacts of different payment modification scenarios. 相似文献
46.
47.
Cerovský V Hovorka O Cvacka J Voburka Z Bednárová L Borovicková L Slaninová J Fucík V 《Chembiochem : a European journal of chemical biology》2008,9(17):2815-2821
A novel antimicrobial peptide designated melectin was isolated from the venom of the cleptoparasitic bee Melecta albifrons. Its primary sequence was established as H-Gly-Phe-Leu-Ser-Ile-Leu-Lys-Lys-Val-Leu-Pro-Lys-Val-Met-Ala-His-Met-Lys-NH(2) by Edman degradation and ESI-QTOF mass spectrometry. Synthetic melectin exhibited antimicrobial activity against both gram-positive and -negative bacteria and it degranulated rat peritoneal mast cells, but its hemolytic activity was low. The CD spectra of melectin measured in the presence of trifluoroethanol and sodium dodecyl sulfate showed a high content alpha-helices, which indicates that melectin can adopt an amphipathic alpha-helical secondary structure in an anisotropic environment such as the bacterial cell membrane. To envisage the role of the proline residue located in the middle of the peptide chain on biological activity and secondary structure, we prepared several melectin analogues in which the Pro11 residue was either replaced by other amino acid residues or was omitted. The results of biological testing suggest that a Pro kink in the alpha-helical structure of melectin plays an important role in selectivity for bacterial cells. In addition, a series of N- and C-terminal-shortened analogues was synthesized to examine which region of the peptide is related to antimicrobial activity. 相似文献
48.
Radka Podlipn Martina Navrtilov Lucie Raisov Stuchlíkov Kateina Mokov Lenka Langhansov Lenka Sklov Barbora Szotkov 《International journal of molecular sciences》2021,22(13)
Although manure is an important source of minerals and organic compounds it represents a certain risk of spreading the veterinary drugs in the farmland and their permeation to human food. We tested the uptake of the anthelmintic drug fenbendazole (FBZ) by soybean, a common crop plant, from the soil and its biotransformation and accumulation in different soybean organs, including beans. Soybeans were cultivated in vitro or grown in a greenhouse in pots. FBZ was extensively metabolized in roots of in vitro seedlings, where sixteen metabolites were identified, and less in leaves, where only two metabolites were found. The soybeans in greenhouse absorbed FBZ by roots and translocated it to the leaves, pods, and beans. In roots, leaves, and pods two metabolites were identified. In beans, FBZ and one metabolite was found. FBZ exposure did not affect the plant fitness or yield, but reduced activities of some antioxidant enzymes and isoflavonoids content in the beans. In conclusion, manure or biosolids containing FBZ and its metabolites represent a significant risk of these pharmaceuticals entering food consumed by humans or animal feed. In addition, the presence of these drugs in plants can affect plant metabolism, including the production of isoflavonoids. 相似文献
49.
The yeast Zygosaccharomyces rouxii is known for its high tolerance to osmotic stress, which is thought to be caused by sets of specific genes. Relatively few Z. rouxii genes have been identified so far, all of them having homologues in Saccharomyces cerevisiae; none of them was Z. rouxii-specific. Most of the known Z. rouxii genes were isolated from two wild-type strains, ATCC 2623 and ATCC 42981. In this study, we compared these two strains with regard to some of their morphological, physiological and genomic properties. Important differences were found in their salt tolerance and assimilation of glycerol and karyotype; slight differences were also present in their cell morphology. The ATCC 42981 strain showed a higher resistance to salts, higher glycerol production and, unlike ATCC 2623, was able to assimilate glycerol. Under conditions of osmotic stress, the glycerol production in both Z. rouxii strains was much lower than in a S. cerevisiae S288c culture, which suggested the presence of a system that efficiently retains glycerol inside Z. rouxii cells. The karyotype analysis revealed that ATCC 42981 cells contain more chromosomes and have a bigger genome size than those of ATCC 2623. 相似文献
50.
Nanofibrous composite membranes were prepared by the elecrospinning process of poly(vinyl butyral) (PVB) solution that contained hydrophobic silica nanoparticles (SiO2). Various surface modifications of the silica nanoparticles have been used to improve the waterproofing capacity of the membrane. Specifically, investigation was made into the effects of the rheological properties of the solution, as well as on fibre diameter as exerted by the applied voltage and the tip-to-collector distance. It was found that drastically increasing shear viscosity and the elasticity of the solution with the silica nanoparticles demonstrated a negligible effect on the creation of nanofibres, an issue rarely discussed in the literature. In fact, increasing the applied voltage and the tip-to-collector distance resulted in heightening the average fibre diameter. According to water contact angle measurements, the given PVB nanofibrous membrane reinforced with the incorporated silica nanoparticles demonstrated superhydrophobic surface properties. 相似文献