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131.
PET is one of the most advanced medical imaging systems widely applied to medical research and clinical use. The present PET scanning technique cannot be performed in small animals such as mice. The detector is not optimal with respect to radiotracer sensitivity due to the lack of spatial resolution. (The problem is further exacerbated due to the lack of a computer model and the unknown amount of radiotracers to be administered for viable detection in small animals.) Thus, the authors are working on a feasibility study to show whether present PET scanning systems can be modified to identify active tumor foci in an orthotopic mouse model of human pancreatic cancer. This way the efficacy of selected standard chemotherapy drugs and novel biological agents can be tested. Ultimately, the goal is the development of novel therapeutic agents against human pancreatic cancer 相似文献
132.
Superhydrophobic Mats of Polymer-Derived Ceramic Fibers 总被引:1,自引:0,他引:1
Sourangsu Sarkar Anindarupa Chunder Weifeng Fei Linan An Lei Zhai 《Journal of the American Ceramic Society》2008,91(8):2751-2755
Solid preceramic polyaluminasilazane was synthesized through the reaction between liquid cyclosilazane and aluminum tri-sec-butoxide at 160°C. Electrospinning of polyaluminasilazane/polyethyleneoxide (1/0.0001 mass ratio) in chloroform solutions generated smooth fibers while the electrospun fibers from the chloroform/ N,N -dimethylformamide solutions had submicrometer structures on the fiber surfaces. Smooth and rough SiCNO ceramic fibers were obtained by the pyrolysis of the green fibers with an 80% yield. Superhydrophobic mats of ceramic fibers were fabricated via a chemical vapor deposition of perfluorosilane onto the rough fibers. These superhydrophobic mats possess good chemical and thermal stability. 相似文献
133.
Minimum norm mutual coupling compensation with applications in direction of arrival estimation 总被引:1,自引:0,他引:1
Lau C.K.E. Adve R.S. Sarkar T.K. 《Antennas and Propagation, IEEE Transactions on》2004,52(8):2034-2041
This paper introduces a new mutual coupling compensation method based on the minimum norm solution to an underdetermined system of equations. The crucial advantage over previous techniques is that the formulation is valid independent of the type of antenna element and provides good results in situations where signal strengths vary considerably. In using the matrix pencil algorithm to estimate the directions of arrival, the examples show that the proposed method results in significantly lower bias than the traditional open circuit method. The analysis of mutual coupling is also applied in the context of a code division multiple access communication system. 相似文献
134.
It is well known that the homogeneous elastic half space does not allow the torsional surface wave to propagate. The present article attempts to study the possibility of propagation of such waves in a liquid-filled initially stressed poroelastic layer over nonhomogeneous half space. The study concludes that torsional surface waves may propagate in the poroelastic layer. The presence of fluid in pores and initial compressive stresses diminishes the velocity. The nonhomogeneity in rigidity and density of the half space also has a certain role to play in initiating, enhancing, or diminishing the velocity of torsional surface waves. 相似文献
135.
Subhashis Roy Anup Dey Bikram Biswas Subir Kumar Sarkar 《Journal of Materials Engineering and Performance》2018,27(6):2635-2642
Ethanol sensors based on different WO3 and ZnO structures are studied in the present work. The XRD and SEM processes are used to characterize the sensing layer’s surface morphology which reveals the presence of nanoparticle in sensing layer. Further reducing the nanoparticle diameter by the addition of palladium (Pd) and platinum (Pt) for both the sensors (ZnO and WO3) gives good results on sensitivity, operating temperature, response time and recovery time. Nanoparticle diameter for undoped WO3, Pd-modified WO3 and Pt-modified WO3 based sensors is 11.8, 6 and 5.4 nm, whereas nanoparticle diameter for undoped, Pd-modified and Pt-modified ZnO based sensors is 20, 14 and 11 nm, respectively. Analysis of dynamic response of the sensors when exposed to different concentrations of ethanol vapour (from 500 to 10,000 ppm) and various temperatures indicate the improvement in sensitivity up to 77.2% for WO3 and 74.6% for ZnO based sensors. 相似文献
136.
Juntunen E. Leung M. C.-H. Barale F. Rachamadugu A. Yeh D. A. Perumana B. G. Sen P. Dawn D. Sarkar S. Pinel S. Laskar J. 《Microwave Theory and Techniques》2010,58(2):348-355
137.
Ultra thin HfAlOx high-k gate dielectric has been deposited directly on Si1−xGex by RF sputter deposition. The interfacial chemical structure and energy-band discontinuities were studied by using X-ray photoelectron spectroscopy (XPS), time of flight secondary ion mass spectroscopy (TOF-SIMS) and electrical measurements. It is found that the sputtered deposited HfAlOx gate dielectric on SiGe exhibits excellent electrical properties with low interface state density, hysteresis voltage, and frequency dispersion. The effective valence and conduction band offsets between HfAlOx (Eg = 6.2 eV) and Si1−xGex (Eg = 1.04 eV) were found to be 3.11 eV and 2.05 eV, respectively. In addition, the charge trapping properties of HfAlOx/SiGe gate stacks were characterized by constant voltage stressing (CVS). 相似文献
138.
Kripamoy Sarkar Avyaktanand Tiwary T. N. Singh 《Bulletin of Engineering Geology and the Environment》2010,69(4):599-606
The accurate determination of geomechanical properties such as uniaxial compressive strength and shear strength requires considerable
time in collecting appropriate samples, their preparation and laboratory testing. To minimize the time and cost, a number
of empirical relations have been reported which are widely used for the estimation of complex rock properties from more easily
acquired data. This paper reports the use of an artificial neural network to predict the deformation properties of Coal Measure
rocks using dynamic wave velocity, point load index, slake durability index and density. The results confirm the applicability
of this method. 相似文献
139.
Kadhim Mustafa M. Rheima Ahmed Mahdi Shadhar Mohanad Hatem Abdulnabi Shuaib M. Saleh Zuhra Muter Al Mashhadani Zuhair I. Najm Zainab Mohsen Sarkar A. 《SILICON》2023,15(1):417-424
Silicon - A theoretical research study was conducted into the possibility of using a two-dimensional graphene-like material silicon carbide nano-sheet (2D-SiCNS) as an anode in rechargeable Ca-ion... 相似文献
140.
A. Sarkar K. Boopathy J. Eapen K. L. Murty 《Journal of Materials Engineering and Performance》2014,23(10):3649-3656
Zirconium (Zr) alloys are the primary structural materials of most water reactors. Creep is considered to be one of the important degradation mechanisms of Zr alloys during reactor operating and repository conditions. Zr alloys pick up hydrogen (H2) during their service from the coolant water. Hydrogen can be present in solid solution or precipitated hydride form in Zr alloys depending upon the temperature and concentration. This study reviews the effect of hydrogen on creep behavior of Zr alloys used in the water reactors. 相似文献