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排序方式: 共有578条查询结果,搜索用时 15 毫秒
1.
N. K. Acharya P. K. Yadav S. Wate Y. K. Vijay F. Singh D. Kavasthi 《Bulletin of Materials Science》2004,27(5):417-420
Ion irradiation of Si8+ ion beam of 100 MeV was scattered by a gold foil on a Mylar membrane of 25 Μm thickness in the form of film roll (width,
12.5 cm and length, 400 cm) at the Nuclear Science Centre, New Delhi. The characterization of etched nuclear tracks was carried
out by gas permeation measurements. The samples cut from the film roll of required size for permeability measurements were
etched in a controlled manner in a constant temperature bath of 6N NaOH solution. The opening of the conical etched tracks
was characterized by hydrogen gas permeation. 相似文献
2.
Inhibition of sickle beta-chain (betaS)-dependent polymerization by nonhuman alpha-chains. A superinhibitory mouse-horse chimeric alpha-chain 总被引:1,自引:0,他引:1
P Nacharaju RP Roy SP White RL Nagel AS Acharya 《Canadian Metallurgical Quarterly》1997,272(44):27869-27876
Horse alpha-chain inhibits sickle beta-chain-dependent polymerization; however, its inhibitory potential is not as high as that of mouse alpha-chain. Horse alpha-(1-30) and alpha-(31-141) segments make, respectively, minor and major contributions to the inhibitory potential of horse alpha-chain. The sum of the inhibitory potential of the two segments does not account for the inhibitory potential of the full-length horse alpha-chain. Although the polymerization inhibitory potential of horse alpha-chain is lower than mouse alpha-chain, the inhibitory potential of horse alpha-(31-141) is comparable to that of mouse alpha-(31-141). When mouse alpha-(1-30) is stitched to horse alpha-(31-141), the product is a chimeric alpha-chain with an inhibitory potential greater than mouse alpha-chain. In contrast, the stitching of horse alpha-(1-30) with mouse alpha-(31-141) had no additional inhibitory potential. Molecular modeling studies of HbS containing the mouse-horse chimeric alpha-chain indicate altered side-chain interactions at the alpha1beta1 interface when compared with HbS. In addition, the AB/GH corner perturbations facilitate a different stereochemistry for the interaction of the epsilon-amino group of Lys-16(alpha) with the beta-carboxyl group of Asp-116(alpha), resulting in a decrease in the accessibility of the side chain of Lys-16(alpha) to the solvent. Based on molecular modeling, we speculate that these perturbations by themselves, or in synergy with the altered conformational aspects of the alpha1beta1 interactions, represent the molecular basis of the superinhibitory potential of the mouse-horse chimeric alpha-chains. 相似文献
3.
Nirmal Kumar Acharya Young-Dai Lee Jong-Soon Kim 《Canadian Metallurgical Quarterly》2006,20(2):192-195
Design defects are experienced in many projects; the difference is only in the extent of occurrence. This technical note discusses a design error case in a building project in Nepal, where the designer made the wrong assumptions in roof treatment work for waterproofing as well as for heat insulation purposes. From the investigation of the problem, it was found that the waterproofing polymer was not applied directly over concrete slab top. Use of heavy concrete block as a heat insulation material also helped to increase the leakage problem. The problem evoked loss of prestige for project officials, the design consortium, and the contractor. 相似文献
4.
The binding of heterotrimeric GTP-binding proteins (G-proteins) to serpentine receptors involves several independent contacts. We have deduced the points of interaction between mutant bovine rhodopsins and alphat-(340-350), a peptide corresponding to the C terminus of the alpha subunit (alphat) of bovine retinal G-protein, transducin. Direct binding of alphat-(340-350) to rhodopsin stabilizes the activated metarhodopsin II state (M II), consequently uncoupling the rhodopsin-transducin interaction. This peptide action requires two segments on the cytoplasmic domain of rhodopsin: the Tyr136-Val137-Val138-Val139 sequence on the C-D loop and the Glu247-Lys248-Glu249-Val250-Thr251 sequence on the E-F loop. We propose that a tertiary interaction of these two loop regions forms a pocket for binding the alphat C terminus of the transducin during light transduction in vivo. In most G-proteins, the C termini of alpha subunits are important for interaction with receptors, and, in several serpentine receptors, regions similar to those in rhodopsin are essential for G-protein activation, indicating that the interaction described here may be a generally applicable mode of G-protein binding in signal transduction. 相似文献
5.
Most interaction recognition approaches have been limited to single‐person action classification in videos. However, for still images where motion information is not available, the task becomes more complex. Aiming to this point, we propose an approach for multiperson human interaction recognition in images with keypoint‐based feature image analysis. Proposed method is a three‐stage framework. In the first stage, we propose feature‐based neural network (FCNN) for action recognition trained with feature images. Feature images are body features, that is, effective distances between a set of body part pairs and angular relation between body part triplets, rearranged in 2D gray‐scale image to learn effective representation of complex actions. In the later stage, we propose a voting‐based method for direction encoding to anticipate probable motion in steady images. Finally, our multiperson interaction recognition algorithm identifies which human pairs are interacting with each other using an interaction parameter. We evaluate our approach on two real‐world data sets, that is, UT‐interaction and SBU kinect interaction. The empirical experiments show that results are better than the state‐of‐the‐art methods with recognition accuracy of 95.83% on UT‐I set 1, 92.5% on UT‐I set 2, and 94.28% on SBU clean data set. 相似文献
6.
In large antenna arrays, the possibility of occurrence of faults in some of the radiating elements cannot be precluded at all times. In such situations, the radiation pattern of the array gets distorted, mostly with an increase in sidelobe level and decrease in gain. Although it is not possible to restore the pattern fully by rearranging the excitations of the functioning elements, compensation methods have been reported in the literature for restoring one performance parameter of the array and making a trade‐off on some other parameter. In this article, we have made a study on the tolerance level of this compensation process. One part of the study deals with the thinning in the failed array, that is, to find a limit on the minimum number of functioning elements of the array that can restore the digital beamforming of the failed array. The second part of study deals with finding the maximum number of element failures that can be compensated. The study was carried out by optimizing the amplitude excitations of the failed array. Instead of classical optimization techniques, particle swarm optimization was used for the compensation process. © 2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 24:635–645, 2014. 相似文献
7.
Steam reforming of isobutane on a 0.5% Pt–Ce0.8Gd0.2O1.9 catalyst was carried out from 300 to 700 °C under integral conditions with a gas hourly space velocity (GHSV) of 12,000 h−1. The major products were H2, CO2, CO and CH4. The other products produced were ethane, ethylene, propane and propylene with a total molar composition of less than 1.5%.
A complete conversion of isobutane was achieved at 700 °C, Kinetic data was obtained by changing the partial pressure of the
reactants and the temperature under differential conditions with a GHSV of 55,400 h−1. This was done after observing stable isobutane steam reforming for 160 h and under conditions where the mass transfer limitations
were insignificant. An empirical Langmuir–Hinshelwood type model that best fit the kinetic data available was developed. 相似文献
8.
Jen Hong Tan U. Rajendra Acharya Choo Min Lim K. Thomas Abraham 《Digital Signal Processing》2013,23(3):1022-1031
Feasible clinical application of any automated segmenting methodology demands more than just accuracy. Amendment to the automated delineation is necessary when the algorithm fails, however, integrated solution to such a scenario is largely absent in literature. Hence in this survey we devised an architecture that does both the automated and interactive lung field localizations using a single segmenting engine—random walker algorithm—so that intuitive amendment is only necessary when the automated generated delineation is unsatisfactory. The algorithm proceeds by first extracting 18 intensity profiles running horizontally, each of them equally spacing apart, and in each intensity profile three extreme points denoting the two lungs and the esophagus are determined through profile matching. This done, the algorithm removes profiles that do not intersect with the lung, and the rest of the extreme points are plugged into random walker algorithm to perform segmentation. The achieved accuracy in localization by the above was 0.8875 in terms of overlap measure (the maximum value for this parameter is 1) over 341 images. In the case where unsatisfactory delineation prompts amendment necessary, the user can interactively segment the lung by just a shift on some of the previous-determined points to the desired locations, and random walker algorithm is run again with the amended input. By such a fusion, the benefits of both the automated and interactive segmentation are shared in a single architecture. 相似文献
9.
Finding fault elements in linear antenna arrays using bacteria foraging optimization (BFO) is presented. One of the better options of array diagnosis is to perform it by measuring the radiated field, because in this case, removal of the array from its working site is not required and thereby not interrupting its normal operation. This task of fault finding from far‐field data is designed as an optimization problem where the difference between the far‐field power pattern obtained for a given configuration of failed element(s) and the measured one is minimized w. r. t. the excitations of the array elements. This set of excitations on comparison with the excitations of the original array gives the idea of the fault position and their type, such as either complete fault or partial fault. BFO being relatively new to microwave community when compared with other soft‐computing techniques, its performance was observed w. r. t. time of computation and convergence of the iterative process. Possibility of finding the faults from random sample points and use of minimum number of sample points for array fault finding are the novelties of the present work. © 2012 Wiley Periodicals, Inc. Int J RF and Microwave CAE, 2013. 相似文献
10.