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Chinese Chemical Letters 2009年第10期20卷 1145-1149页

作者： Shweta sharma Abdul Rauf Department of Chemistry Aligarh Muslim UniversityAligarh 202002 India

The efficient cycloaddition reactions were carried out to afford the novel 3,5-disubstituted-dihydroisoxazoles from methyl undec-10-enoate and isoxazoles, triazole and tetrazolo-triazole from methyl undec-10-ynoate. T... 详细信息

关键词： 3,5-Disubstituted-dihydroisoxazoles Triazole Methyl undec-10-enoate and undec-10-ynoate

On the non-Gaussian errors in high-z supernovae type Ia data

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Research in Astronomy and Astrophysics 2016年第11期16卷 53-56页

作者： Meghendra Singh Ashwini Pandey Amit sharma Shashikant Gupta Satendra sharma Dr. A.EJ. Abdul Kalam Technical University Uttar Pradesh Lucknow 226021 India GD Goenka University Gurgaon Haryana 122103 India Yobe State University Damaturu Yobe State Nigeria

The nature of random errors in any data set is Gaussian, which is a well established fact according to the Central Limit Theorem. Supernovae type Ia data have played a crucial role in major discoveries in cosmology. Unlike in laboratory experiments, astronomical measurements cannot be performed in controlled situations. Thus, errors in astronomical data can be more severe in terms of systematics and non-Gaussianity compared to those of laboratory experiments. In this paper, we use the Kolmogorov-Smiruov statistic to test non-Gaussianity in high-z supernovae data. We apply this statistic to four data sets, i.e., Gold data （2004）, Gold data （2007）, the Union2 catalog and the Union2.1 data set for our analysis. Our results show that in all four data sets the errors are consistent with a Gaussian distribution.

关键词： cosmology - data analysis - statistics - probability

Turbulence characteristics of flow past submerged vanes

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International Journal of Sediment Research 2020年第1期35卷 42-56页

作者： Himanshu sharma Zulfequar Ahmad Department of Civil Engineering Institute of Infrastructure Technology Research and Management Department of Civil Engineering IIT Roorkee

Submerged vanes are hydrofoils utilized to manage the sediment transport through the river by generating the turbulence in the flow in the form of helical *** vanes are placed in the flow with respect to its direction at angle of 10°to 40°.In the current study,an attempt has been made to study the effect of the introduction of vanes in form of rows on parameters like turbulence intensities,Reynolds stresses,turbulent kinetic energy,anisotropy index,and the velocity profile of the *** is observed that the profile of variation of turbulence intensities,turbulent kinetic energy,vertical Reynolds stress and velocity over three different marked verticals on a transect are nearly identical whereas a large scatter is observed in the variation of transverse Reynolds stress over the vertical of the aforementioned vertical *** observation suggests that flow turbulence is homogeneous over the vertical while scattering in the variation of the transverse Reynolds stress component may be attributed to the presence of secondary currents in the *** introducing rows of submerged vanes,the bed turbulence is reduced,hence,helping reduce many scour related *** is also observed that a vortex occurred at 0.85 times the height of the vane and the variation of turbulence quantities in the presence of vanes shows the existence of a peak in these *** is observed that as flow moves away from the vane rows,due to the interaction of vortices and the action of vorticity,vortices dampens down and the flow regains *** the introduction of submerged vane rows,bed shear stress reduces as fluid from the surface replaces the slow-moving fluid near the bed due to the secondary currents generated by the vanes leading to reduction in the magnitude of turbulence intensities,Reynolds stresses,and turbulent kinetic energy near the *** anisotropy index is observed to increase near the bed as induced secondary currents enhanced the turbulence

关键词： Turbulence Anisotropy Submerged vanes Secondary currents Turbulence parameters

Background Dynamics of Pre-inflationary Scenario in Brans-Dicke Loop Quantum Cosmology

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Communications in Theoretical Physics 2019年第10期71卷 1205-1218页

作者： Manabendra sharma Tao Zhu Anzhong Wang Institute for Theoretical Physics and Cosmology Zhejiang University of TechnologyHangzhou310023China GCAP-CASPER Department of PhysicsBaylor UniversityWacoTX76798-7316USA

Recently the background independent nonperturbative quantization has been extended to various theories of gravity and the corresponding quantum effective cosmology has been derived, which provides us with necessary avenue to explore the pre-inflationary dynamics. Brans-Dicke(BD) loop quantum cosmology(LQC) is one of such theories whose effective background dynamics is considered in this article. Starting with a quantum bounce, we explore the pre-inflationary dynamics of a universe sourced by a scalar field with the Starobinsky potential in BD-LQC. Our study is based on the idea that though Einstein’s and Jordan’s frames are classically equivalent up to a conformal transformation in BD theory, this is no longer true after quantization. Taking the Jordan frame as the physical one we explore in detail the bouncing scenario which is followed by a phase of a slow roll inflation. The three phases of the evolution of the universe, namely, bouncing, transition from quantum bounce to classical universe, and the slow roll inflation, are noted for an initially kinetic energy dominated bounce. In addition, to be consistent with observations, we also identify the allowed phase space of initial conditions that would produce at least 60 e-folds of expansion during the slow roll inflation.

关键词： loop quantum cosmology Brans-Dicke theory inflation quantum bounce

Effect of organic component(tartrate) addition on cerium nitrate's ability to inhibit corrosion of mild steel in NaCl solution

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Journal of Rare Earths 2024年第10期42卷 1995-2002页

作者： Minakshi Koundal Chhaya sharma A.K.Singh Department of Applied Science and Engineering Indian Institute of Technology RoorkeeSaharanpur CampusSaharanpurU.247001India Department of Pulp and Paper Technology Indian Institute of Technology Roorke Saharanpur CampusSaharanpurU.p247001India

Cerium tartrate(CeTar),produced in this study by precipitating cerium nitrate with potassium sodium tartrate(KNaTar),was examined as a corrosion *** loss tests show inhibition efficiency of 71.7% with Ce(NO_(3))_(3) and 88.7% with CeTar inhibitor for one-month exposure to mild steel in 7 g/L NaCl *** inhibition efficiency drops to 28.6% with the fo rmer and remains around 8 7% with the latter inhibitor after six months of *** results from electrochemical testing indicate that the inhibition efficiency decreases by adding cerium ***,the cerium tartrate inhibitor demonstrates a nearly constant inhibition efficiency for up to 30 d,i.e.,≈90%.Electrochemical impedance spectroscopy(EIS) performed in these cases shows the following results:(ⅰ) with cerium nitrate,a film of iron and cerium oxide,which on prolonged exposure diminishes,and(ⅱ) with cerium tartrate,the formation of a bimetallic film(Fe-tartrate-Ce) and a mixture of cerium hydroxide and iro n oxide that protects steel for a longer *** inferences are based on the analyses of scanning electron microscopy/energydispersive X-ray analysis(SEM/EDAX),X-ray diffraction(XRD),Fourier transform infrared spectroscopy(FTIR),X-ray photoelectron(XPS),and Raman spectroscopy results.

关键词： Cerium tartrate Cerium nitrate Corrosion inhibition Mild steel Inhibitor film characterization Rare earths

Assessing the effects of different dielectrics onenvironmentally conscious powder-mixed EDM of difficult-to-machine material （WC-Co）

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Frontiers of Mechanical Engineering 2016年第4期11卷 374-387页

作者： Jagdeep SINGH Rajiv Kumar sharma Department of Mechanical Engineering National Institute of Technol-ogy Hamirpur Himachal Pradesh-177005 India

Electrical discharge machining (EDM) is a well-known nontraditional manufacturing process to machine the difficult-to-machine (DTM) materials which have unique hardness properties. Researchers have successfully performed hybridization to improve this process by incorporating powders into the EDM process known as powder-mixed EDM process. This process drastically improves process efficiency by increasing material removal rate, micro-hardness, as well as reducing the tool wear rate and surface roughness. EDM also has some input parameters, including pulse-on time, dielectric levels and its type, current setting, flushing pressure, and so on, which have a significant effect on EDM performance. However, despite their positive influence, investigating the effects of these parameters on environmental conditions is necessary. Most studies demonstrate the use of kerosene oil as dielectric fluid. Nevertheless, in this work, the authors highlight the findings with respect to three different dielectric fluids, including kerosene oil, EDM oil, and distilled water using one-variable-at-a-time approach for machining as well as environmental aspects. The hazard and operability analysis is employed to identify the inherent safety factors associated with powder-mixed EDM of WC-Co.

关键词： WC hazard and operability analysis (HAZOP) discharging aerosol concentration dielectrics powders

Vibration analysis of axisymmetric functionally graded viscothermoelastic spheres

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Acta Mechanica Sinica 2014年第1期30卷 100-111页

作者： D.K.sharma J.N.sharma S.S.Dhaliwal V.Walia Department of Mathematics Sant Longowal Institute of Engineering and Technology Department of Mathematics National Institute of Technology

The present study focuses on the analysis of free vibrations of axisymmetric functionally graded hollow spheres. The material is assumed to be graded in radial di- rection with a simple power law. Matrix Frrbenious method of extended power series is employed to derive the analytical solutions for displacement, temperature, and stresses. The dispersion relations for the existence of various types of pos- sible modes of vibrations in the considered hollow sphere are derived in a compact form. In order to explore the character- istics of vibrations, the secular equations are further solved by using fixed point iteration numerical technique with the help of MATLAB software. The numerical results have been presented graphically for polymethyl methecrylate materials in respect of natural frequencies, frequency shift, inverse quality factor, displacement, temperature change, and radial stress.

关键词： Functionally graded Stresses Vibrations Fr6benius - Dispersion - Spherical structures

PAPR Reduction in NOMA by Using Hybrid Algorithms

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Computers, Materials & Continua 2021年第10期69卷 1391-1406页

作者： Mohit Kumar sharma Arun Kumar Department of Electronics and Communication Engineering JECRC UniversityJaipur303905India

Non-orthogonal multiple access(NOMA)is gaining considerable attention due to its features,such as low out-of-band radiation,signal detection capability,high spectrum gain,fast data rate,and massive D2D *** may be considered for 5G ***,the high peak-to-average power ratio(PAPR)is viewed as a significant disadvantage of a NOMA waveform,and it weakens the quality of signals and the throughput of the *** this article,we introduce a modified NOMA system by employing a block of wavelet transform,an alternative to FFT(Fast Fourier transform).The modified system combines the details of fractional frequency and time analysis of NOMA *** this correspondence,we utilize an advanced partial transmission scheme(PTS),and selective mapping(SLM),and present a genetic algorithm(GA)for SLM to investigate the peak power performance of a WT-based NOMA *** performance of WT-SLM,WT-PTS,and WT-SLM-GA methods is compared with that of the traditional NOMAbased SLM and PTS *** simulation results demonstrate that the proposed system effectively reduces PAPR in comparison with the traditional schemes.

关键词： PAPR wavelet transform NOMA PTS SLM 5G

View Creation for Queriesin Object Oriented Databases

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Journal of Computer Science & Technology 1999年第4期14卷 349-362页

作者： RajeshNarang K.D.sharma DepartmentofComputerScience UniversityofDelhiDelhi110007，I DepartmentofComputerScience Universityof

A view in object oriented databases corresponds to virtual schemawith restructured generalization and decomposition hierarchies. Numbers of viewcreation methodologies have been proposed. A major drawback of existing method-ologies is that they do not maintain the closure property. That is, the result of aquery does not have the same semantics as embodied in the object oriented datamodel. Therefore, this paper presents a view creation methodology that derives aclass in response to a user's query, integrates derived class in global schema (i.e.,considers the problem of classes moving in class hierarchy) and selects the requiredclasses from global schema to create the view for user's query. Novel idea of viewcreation includes: (a) an object algebra for class derivation and customization (wherethe derived classes in terms of object instances and procedure/methods are studied),(b) maintenance of closure property, and (c) classification algorithm which providesmechanism to deal with the problem of a class moving in a class hierarchy.

关键词： object manipulation type level operation instance level operation,object algebra object operator operator syntax operator semantics derived class,class integration view creation algorithm

Comparative and quantitative analysis of antioxidant and scavenging potential of Indigofera tinctoria Linn. extracts

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Journal of Integrative Medicine 2015年第4期13卷 269-278页

作者： Rashmi Singh Shatruhan sharma Veena sharma Department of Bioscience and Biotechnology Banasthali University Maa Aananad Mai Institute

OBJECTIVE：To compare and elucidate the antioxidant effi cacy of ethanolic and hydroethanolic extracts of Indigofera tinctoria Linn.（Fabaceae family）.METHODS：Various in-vitro antioxidant assays and free radical-scavenging assays were *** measurements of various phytoconstituents,reductive abilities and chelating potential were carried out along with standard *** inhibitory concentration（IC50）values for ethanol and hydroethanol extracts were analyzed and compared with respective ***：Hydroethanolic extracts showed considerably more potent antioxidant activity in comparison to ethanol *** extracts had lower IC50values than ethanol extracts in the case of DPPH,metal chelation and hydroxyl radical-scavenging capacity（829,659 and 26.7μg/m L）but had slightly higher values than ethanol in case of SO2-and NO2-scavenging activity（P〈0.001 vs standard）.Quantitative measurements also showed that the abundance of phenolic and fl avonoid bioactive phytoconstituents were signifi cantly（P〈0.001）greater in hydroethanol extracts（212.920 and 149.770 mg GAE and rutin/g of plant extract respectively）than in ethanol extracts（211.691 and 132.603 mg GAE and rutin/g of plant extract respectively）.K arl Pearson’s co rrelation analysis（r2）between various antioxidant parameters and bioactive components also associated the antioxidant potential of *** with various phytoconstituents,especially phenolics,fl avonoids,saponins and ***：This study may be helpful to draw the attention of researchers towards the hydroethanol extracts of ***,which has a high yield,and great prospects in herbal industries to produce inexpensive and powerful herbal products.

关键词： plant extracts Indigofera tinctoria Fabaceae phytoconstituents antioxidant scavenging assays