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1.
Kurian A.P. Puthusserypady S. Su Myat Htut 《Wireless Communications, IEEE Transactions on》2005,4(3):984-989
In this paper, a novel direct sequence/spread spectrum (DS/SS) communication system is proposed. This scheme exploits the two-dimensional complex valued chaotic Ikeda map as the spreading sequences. With this double spreading DS/SS system, the effect of multiple access interference can be mitigated by choosing the spreading sequences with appropriate cross-correlation properties. The performance of the system is assessed and demonstrated in a multiuser environment by means of computer simulation with additive white Gaussian noise, Rayleigh fading, and selective fading channel conditions. These studies reveal that the proposed system significantly outperforms the Gold code DS/SS-BPSK system in synchronous channel conditions. In asynchronous case, the improvement is substantial for low signal-to-noise ratios. 相似文献
2.
MS Kurian RS de la Cuesta GL Waneck DT MacLaughlin TF Manganaro PK Donahoe 《Canadian Metallurgical Quarterly》1995,1(3):343-349
Müllerian inhibiting substance (MIS), an inhibitor of growth and development of the female reproductive ducts in male fetuses, requires precise proteolytic cleavage to yield its biologically active species. Human plasmin is now used to cleave and, thereby, activate immunoaffinity-purified recombinant human MIS at its monobasic arginine-serine site at residues 427-428. To avoid the need for exogenous enzymatic cleavage and to simplify purification, we created an arginine-arginine dibasic cleavage site (MIS RR) using site-directed mutagenesis to change the serine at position 428 (AGC) to an arginine (cGC). The mutant cDNA was then stably transfected into a MIS-responsive ocular melanoma cell line, OM431, followed by cloning for amplified expression to test its biological activity in vitro and in vivo. Media from each clone were assayed for production of MIS RR by a sensitive ELISA for holo-MIS, and high- and low-producing clones were selected for further study. Media from the highest MIS RR producer caused Müllerian duct regression in an organ culture bioassay. Other transfections were done with an empty vector (pcDNAI Neo) or a construct lacking the leader sequence and thus failing to secrete MIS, to serve as controls. The OM431 clones containing the MIS RR mutant were growth inhibited in monolayer culture. The high- and low-producing MIS RR OM431 clones, along with transfected OM431 controls, were injected into the tail veins of immunosuppressed severe combined immunodeficiency mice for in vivo analyses. Four to 6 weeks later, pulmonary metastases were counted in uniformly inflated lungs. OM431 clones containing the more easily cleaved MIS RR displayed a significant dose-dependent reduction in pulmonary metastases when compared to the lungs of animals given injections of OM431 clones containing empty vector, leaderless MIS, or wild-type MIS that requires activation by plasmin cleavage. Since the purification protocol of MIS RR is less complicated than that for wild-type MIS, which requires subsequent enzymatic activation, MIS RR can be used for scale-up production with increased yields for further therapeutic trials against MIS-sensitive tumors. 相似文献
3.
High styrene rubber ionomers were prepared by sulfonating styrene–butadiene rubber of high styrene content (high styrene rubber) in 1,2‐dichloroethane using acetyl sulfate reagent, followed by neutralization of the precursor acids using methanolic zinc acetate. The ionomers were characterized using X‐ray fluorescence spectroscopy, Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance spectroscopy (NMR), dynamic mechanical analysis (DMA), and also by the evaluation of mechanical properties. The FTIR studies of the ionomer reveal that the sulfonate groups are attached to the benzene ring. The NMR spectra give credence to this observation. Results of DMA show an ionic transition (Ti) in addition to glass–rubber transition (Tg). Incorporation of ionic groups results in improved mechanical properties as well as retention of properties after three cycles of processing. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 85: 2294–2300, 2002 相似文献
4.
D. C. Agarwal S. Sarin K. Wadhwa R. Vishwakarma M. B. Deshmukh S. Kurian 《Journal of Failure Analysis and Prevention》2005,5(6):70-78
The work presented in Part 1 of this article showed that additions of magnesium chloride (MgCl2) to ammonia solutions reduced the tendency of ammonia-induced stress-corrosion cracking (SCC) initiation in a Cu-5%Ni alloy.
The present work was undertaken to study the SCC behavior of the test alloy exposed to ammonia in the presence of varying
concentrations of MgCl2. The exposure to MgCl2 additions reduced the severity of the ammonia-induced SCC. 相似文献
5.
K. V. Prabhakaran S. R. Naidu E. M. Kurian 《Propellants, Explosives, Pyrotechnics》1995,20(5):238-244
TNP, a heterocyclic nitramine containing a C NO2 functionality, has been studied as regards the kinetics and mechanism of thermal decomposition, morphology and the gaseous products evolved therof, using thermogravimetry (TG), differential thermal analysis (DTA), infrared spectroscopy (IR), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and hot stage microscopy. The elementary cell parameters obtained form the XRD pattern are: a = 18.818 ± 0.005 Å, b = 18.818 ± 0.005 Å and c = 4.867 ± 0.005 Å. The crystal belongs to the hexagonal system with c/a ratio = 0.259. IR spectra of TNP have also been recorded and the bands assigned. Kinetics of thermolysis has been followed both by isothermal TG and IR. The best linearity with a correlation coefficient of 0.986 was obtained for the three-dimensional diffusion controlled Jander-equation. Kinetic parameters were evaluated from the induction period as well as from isothermal TG. Activation energy was found to be 202.05 kJ/mol and log A(in s-1) 22.78 from TG and 181.133 kJ/mol and log A (in s1) 20.97 from IR, respectively. The corresponding values were 171.17 kJ/mol and log A (in s-1) 21.20 from the induction period data. The effect of a series of additives incorporated to the extent of 5 %, on the initial thermolysis of TNP, has also been studied. Evolved gas analysis by IR showed that CO2, NO2, NO and N2O are produced in larger amounts than CO and HCN. The cleavage of the N N bond appears to be the primary step in the thermolysis of TNP. 相似文献
6.
Aryn C. Karpinski Paul A. Kirschner Ipek Ozer Jennifer A. Mellott Pius Ochwo 《Computers in human behavior》2013
Studies have shown that multitasking with technology, specifically using Social Networking Sites (SNSs), decreases both efficiency and productivity in an academic setting. This study investigates multitasking’s impact on the relationship between SNS use and Grade Point Average (GPA) in United States (US; n = 451) and European (n = 406) university students using quantitative and qualitative data analysis. Moderated Multiple Regression analysis results showed that the negative relationship between SNS use and GPA was moderated by multitasking only in the US sample. This may be due to European students being less prone to “disruptive” multitasking. The results provide valuable cautionary information about the impact of multitasking and using SNSs in a learning environment on university students’ GPAs. 相似文献
7.
Tailoring magnetic and dielectric properties of rubber ferrite composites containing mixed ferrites 总被引:1,自引:0,他引:1
M. R. Anantharaman K. A. Malini S. Sindhu E. M. Mohammed S. K. Date S. D. Kulkarni P. A. Joy Philip Kurian 《Bulletin of Materials Science》2001,24(6):623-631
Rubber ferrite composites containing various mixed ferrites were prepared for different compositions and various loadings.
The magnetic and dielectric properties of the fillers as well as the ferrite filled matrixes were evaluated separately. The
results are correlated. Simple equations are proposed to predetermine the magnetic and dielectric properties. The validity
of these equations is verified and they are found to be in good agreement. These equations are useful in tailoring the magnetic
and dielectric properties of these composites with predetermined properties. 相似文献
8.
Compounds of natural rubber, styrene-butadiene rubber, and butadiene rubber are vulcanized at different temperatures and the crosslink density and physical properties of the vulcanizates are compared. It is found that for each compound there is an optimum vulcanization temperature which results in the best compromise of properties for specific applications. 相似文献
9.
E. Muhammad Abdul Jamal P. A. Joy Philip Kurian M. R. Anantharaman 《Polymer Bulletin》2010,64(9):907-923
Rubber–nickel nanocomposites were synthesized by incorporating freshly prepared nanometric nickel particles in two different
matrices namely natural rubber and neoprene rubber according to specific recipes for various loadings of nano nickel and the
cure characteristics of these composites were evaluated. The maximum torque values register an increase with the increase
in loading of nickel in both composites and this is attributed to the non-interacting nature of nickel nanoparticles with
rubber matrices. The cure time of natural rubber composites decreases with increase in the content of nickel, and in neoprene
rubber cure, time increases with increase in filler content. In natural rubber, the curing reaction seems to be activated
by the presence of nickel particles. The magnetization studies of the composites reveal that the magnetic properties of nickel
are retained in the composite samples. The elastic modulus of natural rubber and neoprene rubber are largely improved by the
incorporation of nickel particles. 相似文献
10.
对于大多数住宅楼盘的开而言.售楼中心是必不可少的。当大部分住宅单元售出.售楼中心也就完成了它的历史使命,通常情况下或是被拆除,或是被改造为会所或社区中心,服务于新入住的居民。所以这类售楼中心的设计任务书常常显得很被动:一方面,开发商出于促销的需求,总是追求一个引人瞩目且散发着迷人光彩的地标性建筑.另一方面,过于紧迫的设计周期往往无法为设计师提供深入思考和高品质工作的空间,有关设计优化、生态环境考量和材料、细节研究等大多被忽略。 相似文献