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101.
Adaptive decision feedback detector based on the parallel interference cancellation approach (ADFD-PIC) is presented for code
division multiple access transmission, which not only combats the intersymbol interference and multiple access interference
but also suppresses other-cell interference. For frequency-selective smoothly time-varying channels, the proposed ADFD-PIC
structure using the erasure algorithm based soft-slicer and channel estimator (EC-ADFD-PIC) offers performance improvement
by mitigating the adverse effects of error propagation. The simulation results are presented to demonstrate the substantial
improvement in bit error rate performance of the minimum mean square error EC-ADFD-PIC over other multiuser detection techniques. 相似文献
102.
A long standing goal in protein structure studies is the development of reliable energy functions that can be used both to verify protein models derived from experimental constraints as well as for theoretical protein folding and inverse folding computer experiments. In that respect, knowledge-based statistical pair potentials have attracted considerable interests recently mainly because they include the essential features of protein structures as well as solvent effects at a low computing cost. However, the basis on which statistical potentials are derived have been questioned. In this paper, we investigate statistical pair potentials derived from protein three-dimensional structures, addressing in particular questions related to the form of these potentials, as well as to the content of the database from which they are derived. We have shown that statistical pair potentials depend on the size of the proteins included in the database, and that this dependence can be reduced by considering only pairs of residue close in space (i.e., with a cutoff of 8 A). We have shown also that statistical potentials carry a memory of the quality of the database in terms of the amount and diversity of secondary structure it contains. We find, for example, that potentials derived from a database containing alpha-proteins will only perform best on alpha-proteins in fold recognition computer experiments. We believe that this is an overall weakness of these potentials, which must be kept in mind when constructing a database. 相似文献
103.
Singh NP Sahni V Wadhwa A Garg S Bajaj SK Kohli R Agarwal SK 《Hemodialysis international. International Symposium on Home Hemodialysis》2006,10(3):267-273
Our aim is to study the effect of improvement in anemia on event-related potentials (ERPs; P300) as markers of cognitive dysfunction in predialysis and dialysis patients of chronic kidney disease (CKD). Thirty anemic patients of CKD (hemoglobin [Hb] < 9 g%), 15 in the predialysis group (Group A), and 15 patients on biweekly hemodialysis (Group B) were recruited for the study. Patients of uremic encephalopathy, dyselectrolytemia, and those with hearing problems were excluded. Both groups were given recombinant human erythropoietin (rhuEPO) 100 IU/kg biweekly for 6 weeks by the subcutaneous route. No intervention was performed in the third control group (Group C), which consisted of 30 normal healthy volunteers. The improvement in Hb was assessed every 2 weeks, and the amplitude and latency of the P300 component of the ERPs were studied before initiating treatment and after 6 weeks of rhuEPO administration. There was a significant increase in Hb in both the study groups without any significant alteration in kidney functions. A significant reduction in P300 latency was noted in both the study groups after intervention. Similarly, the amplitude of P300 also increased in both study groups, but attained statistical significance for the dialysis group only. No significant changes were observed in the control group. Administration of EPO in patients of anemia with CKD resulted in a significant improvement in the electrophysiological markers of cognitive function in the form of increased amplitudes and decreased latencies of P300 in both predialysis and dialysis patients. 相似文献
104.
Nipin Kohli Onkar Singh Kanika Anand Ravi Chand Singh 《Materials Research Bulletin》2012,47(8):2072-2076
Nanoparticles of chromium oxide have been synthesized following a precipitation technique at reaction temperatures 5, 27 and 65 °C. Synthesized powders were characterized using X-ray diffraction, transmission electron microscope and Brunauer–Emmett–Teller techniques to carry out structural and morphological analysis. The reaction temperature has been found to be playing a crucial role in controlling particle size. It has been observed that Cr2O3 nanoparticles synthesized at 27 °C were smaller as compared to those synthesized at 5 and 65 °C. Chromium oxide samples thus prepared were deposited as thick films on alumina substrates to act as gas sensors and their sensing response to ethanol vapour was investigated at different operable temperatures. It has been observed that all the sensors exhibited optimum response at 250 °C. The investigations revealed that sensing response of Cr2O3 nanoparticles synthesized at 27 °C was exceptionally higher than that of Cr2O3 nanoparticles synthesized at 5 and 65 °C. 相似文献
105.
Adaptive Mo2N/MoS2/Ag Tribological Nanocomposite Coatings for Aerospace Applications 总被引:1,自引:0,他引:1
Samir M. Aouadi Yadab Paudel Brandon Luster Shane Stadler Punit Kohli Christopher Muratore Carl Hager Andrey A. Voevodin 《Tribology Letters》2008,29(2):95-103
Reactively sputtered Mo2N/MoS2/Ag nanocomposite coatings were deposited from three individual Mo, MoS2, and Ag targets in a nitrogen environment onto Si (111), 440C grade stainless steel, and inconel 600 substrates. The power
to the Mo target was kept constant, while power to the MoS2 and Ag targets was varied to obtain different coating compositions. The coatings consisted of Mo2N, with silver and/or sulfur additions of up to approximately 24 at%. Coating chemistry and crystal structure were evaluated
using X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), which showed the presence of tetragonal Mo2N and cubic Ag phases. The MoS2 phase was detected from XPS analysis and was likely present as an amorphous inclusion based on the absence of characteristic
XRD peaks. The tribological properties of the coatings were investigated in dry sliding at room temperature against Si3N4, 440C stainless steel, and Al2O3. Tribological testing was also conducted at 350 and 600 °C against Si3N4. The coatings and respective wear tracks were examined using scanning electron microscopy (SEM), optical microscopy, profilometry,
energy dispersive X-ray spectroscopy (EDX), and micro-Raman spectroscopy. During room temperature tests, the coefficients
of friction (CoF) were relatively high (0.5–1.0) for all coating compositions, and particularly high against Si3N4 counterfaces. During high-temperature tests, the CoF of single-phase Mo2N coatings remained high, but much lower CoFs were observed for composite coatings with both Ag and S additions. CoF values
were maintained as low as 0.1 over 10,000 cycles for samples with Ag content in excess of 16 at% and with sulfur content in
the 5–14 at% range. The chemistry and phase analysis of coating contact surfaces showed temperature-adaptive behavior with
the formation of metallic silver at 350 °C and silver molybdate compounds at 600 °C tests. These adaptive Mo2N/MoS2/Ag coatings exhibited wear rates that were two orders of magnitude lower compared to Mo2N and Mo2N/Ag coatings, hence providing a high potential for lubrication and wear prevention of high-temperature sliding contacts. 相似文献
106.
C. Venkataraman P. Joshi V. Sethi S. Kohli M. R. Ravi 《Aerosol science and technology》2013,47(1):50-61
Low-temperature combustion in biomass-burning stoves used for cooking results in poor thermal efficiency and high emissions. A sawdust packed-bed stove has been shown to give more stable combustion at higher temperatures than woodstoves. The study examines pollutant emissions from this stove and their dependence on stove dimensions, specifically the vertical port radius and the stove-pot spacing. Emission rates of particulate matter (PM)—along with size resolution—and of carbon monoxide (CO) were measured during steady-state combustion. The stove power increased with increased spacing and vertical port radius. However, the air-flow rate, combustion temperature, and air-fuel ratio showed complex variations with stove dimensions from the described coupling among the pyrolysis, combustion, induced air flow, and mixing. Emission rates of PM (0.21–0.36 gh?1 and CO (3–8 gh?1 and were a factor of ten lower than those previously measured from woodstoves. Emission rates of CO decreased, while PM increased, with increasing combustion temperature. Aerosol size distributions were unimodal with mass median aerodynamic diameters (MMAD) of 0.24–0.40 𝛍 a factor of two smaller than from woodstoves. Cool combustion at 534–625°C gave lower PM emission rates but particles of larger MMAD, while hot combustion at 625–741°C gave higher PM emission rates with smaller particle MMAD. The OC/EC ratio obtained for cool combustion was higher (1.20) than that for hot combustion (0.96). Greater elemental carbon formation was seen at the higher temperatures. PM and CO emission rates followed opposite trends with combustion temperature and stove configuration, resulting in no single configuration at which both CO and PM emissions were minimized. However, its superior thermal efficiency and significantly lower emissions than wood stoves should motivate further study of this device to optimize thermal and emissions performance. 相似文献
107.
The article discusses statistical analysis on Release data from a mature Global Software Group (GSG) with three business domains with an aim to ascertain if any correlation can be established between the data collected after release and the benefits to the centre from the outcome of the analysis. Thus re-evaluating the process involved in creating and delivering software products to our customers. This article will strive to explain some of the Six Sigma methodologies and tools used in comparing groups (ANOVA method) and categorical data analysis techniques on software data. The paper will also discuss in detail normal distribution, tests for normality and comparative methods along with Contingency Table Analysis (Mosaic plots) and Correspondence Analysis. The application of statistics for SOFTWARE process improvement is increasing in the industry; we present how these techniques can be applied in practice. 相似文献
108.
Ophthalmic delivery of ciprofloxacin hydrochloride from different polymer formulations: in vitro and in vivo studies 总被引:1,自引:0,他引:1
Reservoir-type ocular inserts were fabricated using sodium alginate containing ciprofloxacin hydrochloride as the core (drug reservoir) that was sandwiched between the Eudragit and/or polyvinylacetate films. Ocular inserts were packaged in aluminium foil and sterilized by gamma radiation. These were tested for sterility as per British Pharmacopoeia (BP). Ocular inserts were evaluated for in vitro release rate studies, microbial efficacy, in vivo release studies, efficacy against induced bacterial conjunctivitis in rabbit's eyes, concentration in the aqueous humor, and stability studies as per the International Conference on Harmonization (ICH) guidelines. Ocular inserts passed the test for sterility. They showed zero-order release of the drug in the in vitro and in vivo release studies over a period of 120 hr. The drug was found to be active against selected microorganisms as was proved by microbial efficacy studies. A high correlation coefficient was found between in vitro and in vivo release rate studies. Better improvement was observed in artificially induced bacterial conjunctivitis in rabbit's eyes, compared with marketed eye drops and placebo. Drug concentration in the aqueous humor was found above Minimum Inhibitory Concentration (MIC-90) against selected microorganisms. Shelf-life of the product was found to be more than 2 years. 相似文献
109.
In this paper, it is shown that there are a significantly large number of cam-link mechanisms that may be used for generating an exact path or for guiding a body through exactly specified infinite positions. Using Gruebler's mobility criterion, structural synthesis is performed to obtain several cam-link mechanisms for path and motion generation. A synthesis technique is also presented to design track-follower mechanisms. The technique utilizes the complex loop closure method and the envelope theory to find the centerline and the contact points of the track. The approach is general and may be applied to any cam-link mechanism used to generate exact paths or to guide a body through infinitely many positions. A method for finding the curvature of the track at the contact points is also given. 相似文献
110.
The various existing or envisioned applications for so-called telemedicine networks are described. The current and future medical environments are examined with respect to the use of such networks. The characteristics of medical images that affect their transmission and storage are discussed. Medical communication field trials using the emerging broadband networks are described. Some service scenarios and concepts are presented 相似文献