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141.
Majumder SK Gebhart S Johnson MD Thompson R Lin WC Mahadevan-Jansen A 《Applied spectroscopy》2007,61(5):548-557
This paper reports the development of a probability-based spectroscopic diagnostic algorithm capable of simultaneously discriminating tumor core and tumor margins from normal human brain tissues. The algorithm uses a nonlinear method for feature extraction based on maximum representation and discrimination feature (MRDF) and a Bayesian method for classification based on sparse multinomial logistic regression (SMLR). Both the autofluorescence and the diffuse-reflectance spectra acquired in vivo from patients undergoing craniotomy or temporal lobectomy at the Vanderbilt University Medical Center were used to train and validate the algorithm. The classification accuracy was observed to be approximately 96%, 80%, and 97% for the tumor, tumor margin, and normal brain tissues, respectively, for the training data set and approximately 96%, 94%, and 100%, respectively, for the corresponding tissue types in an independent validation data set. The inherently multi-class nature of the algorithm facilitates a rapid and simultaneous classification of tissue spectra into various tissue categories without the need for a hierarchical multi-step binary classification scheme. Further, the probabilistic nature of the algorithm makes it possible to quantitatively assess the certainty of the classification and recheck the samples that are classified with higher relative uncertainty. 相似文献
142.
F. W. Van Keuls C. H. Mueller R. R. Romanofsky J. D. Warner F. A. Miranda S. B. Majumder 《Integrated ferroelectrics》2013,141(1):207-217
Epitaxial Ba x Sr 1 m x TiO 3 (BST) films grown on LaAlO 3 by several deposition methods have been tested in coupled microstrip phase shifters (CMPS) at frequencies from 10 to 24 GHz. To date the best performance for the devices has been achieved using Pulsed Laser Deposition (PLD). However, recently chemical solution deposition (CSD) methods such as sol-gel and Metal-Organic Chemical Liquid Deposition (MOCLD) have shown advances in fabricating BST films for tunable microwave applications. CSD processes promise improvements in cost, speed and area covered during BST film deposition. This paper compares over 35 BST films used in identical CMPS circuits. In this study, the highest measured figures of merit of phase shift per dB of loss for PLD, MOCLD and sol-gel CMPS are 49, 47 and 41°/dB respectively. While other phase shifter designs using BST films have surpassed these values, these data base of identical circuits allows us to compare the BST films. X-ray diffraction characterization for many of the BST films is also given. 相似文献
143.
S. B. Majumder D. C. Agrawal Y. N. Mohapatra V. N. Kulkarni 《Integrated ferroelectrics》2013,141(3-4):271-284
Abstract Thin films of lead zirconate titanate having the composition Pb1.05(Zr0.53Ti0.47)O3 were deposited by a solgel method on a set of crystalline and amorphous substrates. The thickness of the film was varied by controlling the sol concentration or by repeated coatings. Factors controlling phase formation in the films such as nature of the substrate material, film thickness, chemical composition of the film, heating rate and gaseous atmosphere during the heat treatment were studied. On glass substrates the pyrochlore phase was obtained in thin (0.4 um) films and the perovskite phase in thicker (>1.5 um) films. Crystalline substrates (except Si and stainless steel) yielded a perovskite phase in 0.6 um thick film. Low Zr/Ti ratio, rapid heating and introduction of nitrogen in the later stage of heat treatment also favoured the formation of the perovskite phase. It is shown that Pb deficiency in the film caused by diffusion of Pb into amorphous substrates or by other mechanisms is primarily responsible for inhibiting the pyrochlore to perovskite transformation. The initial crystallisation of the amorphous film into pyrochlore rather than a perovskite phase (as in powders) is proposed to be due to higher strain energy barrier which exists for the amorphous to perovskite transformation in the film. 相似文献
144.
Aparna Roy Sumit Chakraborty Sarada Prasad Kundu Basudam Adhikari Subhasish Basu Majumder 《应用聚合物科学杂志》2013,129(1):15-27
The feasibility of the use of jute fiber for the adsorption of azo dye from an aqueous solution was evaluated with batch and fixed‐bed column studies. The batch studies illustrated that dye uptake was highly dependent on different process variables, namely, the pH, initial dye concentration of the solution, adsorbent dosage, contact time, ionic strength, and temperature. The exothermic and spontaneous nature of adsorption was revealed from thermodynamic study. The equilibrium adsorption data were highly consistent with the Langmuir isotherm and yielded an R2 value of 0.999. Kinetic studies divulged that the adsorption followed a pseudo‐second‐order model with regard to the intraparticle diffusion. In the column studies, the total amount of adsorbed dye and the adsorption capacity decreased with increasing flow rate and increased with increasing bed height and initial dye concentration. Also, the breakthrough time and exhaustion time increased with increasing bed depth but decreased with increasing flow rate and influent dye concentration. The column performances were predicted by the application of the bed‐depth service time model and Thomas model to the experimental data. The virgin and dye‐adsorbed jute fiber was characterized by Fourier transform infrared spectroscopy and scanning electron microscopy analyses. The investigation suggested that jute fiber could be applied as a promising low‐cost adsorbent for dye removal. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013 相似文献
145.
The present paper outlines an experimental study to investigate the effects of cutting parameters on finish and power consumption
by employing Taguchi techniques. The high speed machining of AISI 1045 using coated carbide tools was investigated. A combined
technique using orthogonal array and analysis of variance was employed to investigate the contribution and effects of cutting
speed, feed rate and depth of cut on three surface roughness parameters and power consumption. The results showed a significant
effect of cutting speed on the surface roughness and power consumption, while the other parameters did not substantially affect
the responses. Thereafter, optimal cutting parameters were obtained. 相似文献
146.
147.
Debashis Chatterjee Dipti Halder Santanu Majumder Bibhash Nath Subhamoy Bhowmick Debasree Saha Palash B. Maity Abhijit Mukherjee 《Water research》2010,44(19):5803-5812
Arsenic (As) induced identifiable health outcomes are now spreading across Indian subcontinent with continuous discovery of high As concentrations in groundwater. This study deals with groundwater hydrochemistry vis-à-vis As exposure assessment among rural population in Chakdaha block, West Bengal, India. The water quality survey reveals that 96% of the tubewells exceed WHO guideline value (10 μg/L of As). The groundwaters are generally anoxic (−283 to −22 mV) with circum-neutral pH (6.3 to 7.8). The hydrochemistry is dominated by HCO3− (208 to 440 mg/L), Ca2+ (79 to 178 mg/L) and Mg2+ (17 to 45 mg/L) ions along with high concentrations of AsT (As total, below detection limit to 0.29 mg/L), FeT (Fe total, 1.2 to 16 mg/L), and Fe(II) (0.74 to 16 mg/L). The result demonstrates that Fe(II)-Fe(III) cycling is the dominant process for the release of As from aquifer sediments to groundwater (and vice versa), which is mainly controlled by the local biogeochemical conditions. The exposure scenario reveals that the consumption of groundwater and rice are the major pathways of As accumulation in human body, which is explained by the dietary habit of the surveyed population. Finally, regular awareness campaign is essential as part of the management and prevention of health outcomes. 相似文献
148.
In this work, based on first principles density functional theory, we have investigated the interaction of SO3 molecule on three different substrates; (i) clean Al2O3 surface (0001) (ii) an isolated Ag6 cluster and (iii) Ag6 clusters deposited on the Al2O3 surface. All calculations were carried out using the plane wave based pseudopotential method under the framework of density functional theory. For the clean Al2O3 surface, the SO3 molecule was adsorbed in parallel orientation on the surface resulting in an elongation of the S–O bond from 1.44 to 1.52 Å with interaction energy of 1.67 eV. In contrast, the interaction of SO3 with Ag6 was found to be weak with 0.4 eV interaction energy and 1.47 Å as the largest S–O bond length. Remarkably, when SO3 molecule interacted with Ag6 cluster deposited on the Al2O3 support, the binding was found to be higher than both Al2O3 and Ag6 clusters in their isolated state. In particular, upon adsorption of SO3 on Ag6/@Al2O3, the S–O bond length was found to increases from 1.44 to 1.64 Å and the interaction energy was estimated to be 2.00 eV. As the bond elongation bears the signature of bond weakening, a comparison of the above three results clearly suggests that the dissociation barrier of S–O bond on the Ag6@Al2O3 support will be significantly lower than that on the isolated Ag6 or Al2O3 surface. The nature of chemical interaction of SO3 on these three systems has been discussed based on the electronic density of states analysis. 相似文献
149.
The ZrCo intermetallic is considered to be strategically important for hydrogen isotope storage and its use in the International Thermonuclear Experimental Reactor (ITER) system. Here we report the structural, electronic and thermodynamic properties of ZrCo and ZrCoH3 using the first-principles approach. The calculations are performed using a plane-wave based pseudo-potential approach under the framework of spin-polarized density-functional theory. The ground state properties like lattice constants, bulk moduli, and enthalpy of formation have been determined by optimizing the atomic and electronic structure of ZrCo and ZrCoH3 compounds. From the total energy calculations, the enthalpy of formation of ZrCoH3 from ZrCo is estimated to be −91 kJ/mol H2 at 0 K. Both lattice parameters and formation energy are found to be in good agreement with their corresponding experimental values. The nature of chemical bonding in ZrCo and ZrCoH3 has been analyzed from the electronic density of states spectrum of the constituent materials. 相似文献
150.
Successful recapitulation of the anatomical microarchitecture and biomechanics of the native articular cartilage under in vitro culture conditions is still an elusive topic of research. The major roadblock lies in maintaining the stable chondrogenic phenotype in vivo or under long-term in vitro conditions. Tissue engineers worldwide has coined this aberrant loss of permanent cartilage characteristics to transient cartilage form as “chondrocyte hypertrophy”. Although the following has been validated through the expression of a few known markers but very little is understood regarding the molecular mechanism that dwells underneath. This review summarizes the precise aetiology behind the development and progression of the hypertrophic phenotype in chondrocytes under in vitro chondrogenic conditions. Based on the current literature survey, it is deciphered that the type of cell utilized (chondrocytes or stem cells), the chondrogenic culture conditions (growth factors/biochemical mediators) and the culture microenvironment (oxygen tension, mechanical loading) during chondrogenesis have a direct correlation with the dysregulated activity of the chondrogenic signaling pathways corroborating the onset of hypertrophic maturation of chondrocytes. Furthermore, it is critically analyzed whether to completely inhibit these hypertrophy-inducing signaling pathways or apply a brake in terms of time-dependent dose due to their functional duality role in chondrogenesis. 相似文献