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Science China Chemistry 2012年第10期55卷 2154-2160页

作者： MAZAAHIR Kidwai RITIKA chauhan DIVYA Bhatnagar Green Chemistry Research Laboratory Department of ChemistryUniversity of Delhi

A simple and convenient approach for the synthesis of tetraheterocyclic benzothiazolo-[2,3-b]-quinazolin-1-ones has been developed utilizing the MCR methodology, which involves the condensation of 2-aminobenzothiazole, cyclic-diketones and various aldehydes using Amberlyst-15 in PEG 400 as an environmentally benign and reusable catalyst system. Environmental benignity, recyclability, cost-effectiveness, easy workup and excellent yields are the major attributes of this one-pot procedure.

关键词： Amberlyst-15 benzothiazolo-[2 3-b]-quinazolinones multi-component reaction reusability PEG (polyethylene glycol) green chemistry

Optimal promotional policy of an innovation diffusion model incorporating the brand image in a segment-specific market

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Journal of Management Analytics 2022年第1期9卷 120-136页

作者： Kuldeep Chaudhary Pradeep Kumar Sudipa chauhan Vijay Kumar Department of Mathematics AIASAmity UniversityNoidaIndia

This paper addresses the problem of determining the optimal promotional policy for a diffusion model in a segment-specific market under the assumption that the additional demand of the new product also improves brand image in the form of goodwill of the *** model is framed with the assumption that the firm uses the mass and differentiated promotion effort for each *** differentiated promotional efforts target each market segment independently and the mass promotional effort reaches different segments with a fixed *** derive the optimal promotional effort policy for each segment using maximumprinciple and also analyze the stability of the dynamical system by constructing a Lyapunov function through the graph theoretic *** analysis gives a deep insight into how the promotional effort should be planned by the decision makers keeping in mind the financial constrains without hindering the promotional effort at the end of the planning period.

关键词： market-segmentation brand-image maximum-principle stability analysis graph theoretic approach

Studies on induction hardening of powder-metallurgy-processed Fe–Cr/Mo alloys

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International Journal of Minerals,Metallurgy and Materials 2017年第8期24卷 918-925页

作者： Sandeep chauhan Vikas Verma Ujjwal Prakash P.C.Tewari Dinesh Khanduja Department of Mechanical Engineering National Institute of Technology Department of Metallurgical & Materials Engineering Indian Institute of Technology

Induction hardening of dense Fe–Cr/Mo alloys processed via the powder-metallurgy route was studied. The Fe-3Cr-0.5Mo, Fe-1.5Cr-0.2Mo, and Fe-0.85 Mo pre-alloyed powders were mixed with 0.4wt%, 0.6wt%, and 0.8wt% C and compacted at 500, 600, and 700 MPa, respectively. The compacts were sintered at 1473 K for 1 h and then cooled at 6 K/min. Ferrite with pearlite was mostly observed in the sintered alloys with 0.4wt% C, whereas a carbide network was also present in the alloys with 0.8wt% C. Graphite at prior particle boundaries led to deterioration of the mechanical properties of alloys with 0.8wt% C, whereas no significant induction hardening was achieved in alloys with 0.4wt% C. Among the investigated samples, alloys with 0.6wt% C exhibited the highest strength and ductility and were found to be suitable for induction hardening. The hardening was carried out at a frequency of 2.0 kHz for 2–3 s. A case depth of 2.5 mm was achieved while maintaining the bulk(interior) hardness of approximately HV 230. A martensitic structure was observed on the outer periphery of the samples. The hardness varied from HV 600 to HV 375 from the sample surface to the interior of the case hardened region. The best combination of properties and hardening depth was achieved in case of the Fe-1.5Cr-0.2Mo alloy with 0.6wt% C.

关键词： Fe–Cr/Mo alloys powder metallurgy sintered density tensile strength induction hardening case depth

Linear and nonlinear optical changes in amorphous As2Se3 thin film upon UV exposure

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Progress in Natural Science:Materials International 2011年第3期21卷 205-210页

作者： Rashmi chauhan Amit Kumar SRIVASTAVA Arvind TRIPATHI Krishna Kant SRIVASTAVA Department of Physic DAV CollegeCSJM UniversityKanpur208001India Department of Physics DBS CollegeCSJM UniversityKanpur208006India Materials Science Programme 4. Research Foundation for Education and Technology 5. Department of Physics DBS CollegeCSJM University

Amorphous As2Se3chalcogenide thin film was exposed to UV light(i line and g line) using mercury lamp for 30 min. XRD,UV/VIS spectroscopy and thickness measurements were taken for unexposed and exposed thin film for structural and optical *** optical constants(linear refractive index,extinction coefficient and linear optical absorption coefficient) of the film were calculated from transmission spectra using Swanepoel *** bandgap was determined using Tauc’s relation of indirect bandgap *** of the material was described by single-oscillator Wemple-DeDiDomenico model. Nonlinear optical constants(χ~((3)) and n2) were determined from linear optical parameters using semi-empirical relations in long wavelength *** changes in linear optical parameters(increase in refractive index,and extinction coefficient;reduction in optical bandgap),nonlinear optical parameter(increase inχ~((3))) are proposed for various photonic applications.

关键词： amorphous chalcogenide thin films UV exposure optical properties swanepoel method Wemple-DeDiDomenico model semi-empirical relations

Weed Management in Rainfed Upland Rice Fields under Varied Agro-Ecologies in Nigeria

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Rice science 2022年第4期29卷 328-339页

作者： Oyebanji O.ALAGBO Oluyemisi A.AKINYEMIJU Bhagirath S.chauhan Department of Crop Production and Protection Faculty of AgricultureObafemi Awolowo UniversityIle-Ife 220005Nigeria Department of Crop Soil and Pest ManagementOndo State University of Science and TechnologyOkitipupa 353Ondo-StateNigeria Queensland Alliance for Agriculture and Food Innovation/School of Agriculture and Food Sciences The University of QueenslandGatton 4343QueenslandAustralia

The demand for rice to meet the dietary need in low-income countries is expected to witness an exponential rise as the population *** the rice demand domestically has remained challenging due to significant yield loss caused by several biotic and abiotic *** these factors,one of the most important is the high weed pressure that ravages the upland rice *** Nigeria,several independent weed control techniques,such as physical,chemical and cultural methods,have been recommended and adopted for weed control across varying rice upland ***,outcomes of these approaches when used independently have not consistently led to an increase in *** remains an outstanding deficit between the actual yield and the potential rice *** review aimed to identify potential research gaps,and quest effective and sustainable weed management strategies in smallholder upland rice farming systems in Nigeria.A critical analysis of studies suggests the potential of sustainable weed management practices if adopted and adapted smartly in different upland ecologies in *** of upland rice against weeds can be enhanced through strategic integration of weed competitive cultivars,optimum nitrogen application timings(within weed-free periods),uniform plant spacing,and high seeding rates,with conventional herbicide/manual weed control ***,such management practices can only be engaged where inputs are supplied on time and the technical know-how is extended to *** review equally highlights potential research gaps for further studies.

关键词： herbicide integrated weed management weed flora tillage practice rainfed upland rice

Photo-induced optical changes in GexAs40Se60-x thin films

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Progress in Natural Science:Materials International 2010年第1期20卷 54-60页

作者： Rashmi chauhan Amit Kumar SRIVASTAVA Arvind TRIPATHI Krishna Kant SRIVASTAVA Department of Physic DAV College Kanpur 208001India Material Science Programme ⅡT Kanpur 208016 India Epsilonium Systems Commercial Complex ChunniganjKanpur 208001India Department of Physics DBS College Kanpur 208006India

Ge-As-Se chalcogenide thin films show a wide range of photosensitivity,which is utilized for the fabrication of micro-optical elements for integrated *** photosensitivity of GexAs40Se60-x（x=0,15）chalcogenide thin films for UV light was *** that purpose,the bulk samples of GexAs40Se60-x（x=0,15）chalcogenide glasses were prepared using conventional melt quenching technique,and thin films were prepared using thermal evaporation *** thin films were exposed to UV light for two *** natures of bulk samples and thin films were verified by XRD and chemical compositions were verified by EDX *** thicknesses of the thin films were measured using a thickness *** optical analysis of these thin films was done using transmission spectra in wavelength range of 300-900 *** bandgap was determined by first peak of transmission derivative as well as extrapolation of Tauc's plot.R2analysis was done using R software to ensure that the material is indirect bandgap *** is observed that two hours UV exposure causes photo-darkening along with photo-expansion in As40Se60thin films,while photo-bleaching and photo-densification for Ge15As40Se45thin ***,the amounts of photo-induced optical changes for Ge15As40Se45thin films are smaller than those for As40Se60thin *** changes in optical absorption,bandgap and thickness are understood based on the bonding rearrangement caused by UV exposure.

关键词： chalcogenide glasses thin films optical properties photo-induced effect optical band gap UV exposure R software

Implementation of drone technology for farm monitoring&pesticide spraying:A review

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Information Processing in Agriculture 2023年第2期10卷 192-203页

作者： Abdul Hafeez Mohammed Aslam Husain S.P.Singh Anurag chauhan Mohd.Tauseef Khan Navneet Kumar Abhishek chauhan S.K.Soni Rajkiya Engineering College Ambedkar NagarUP 224122India Rajkiya Engineering College BandaUP 210201India Rajkiya Engineering College BijnorUP 246725India MMMUT GorakhpurUP 273016India

The world receives more than 200 thousand people in a day and it is expected that the total world population will reach 9.6 billion by the year *** will result in extra food demand,which can only be met from enhanced crop ***,modernization of the agricultural sector becomes the need of the *** are many constraints that are responsible for the low production of crops,which can be overcome by using drone technology in the agriculture *** paper presents an analysis of drone technologies and their modifications with time in the agriculture sector in the last *** application of drones in the area of crop monitoring,and pesticide spraying for Precision Agriculture(PA)has been *** work done related to drone structure,multiple sensor development,innovation in spot area spraying has been ***,the use of Artificial Intelligent(AI)and deep learning for the remote monitoring of crops has been discussed.

关键词： Unmanned Aerial Vehicle Agriculture drone Pesticide spraying Crop monitoring Precision agriculture

siRNA-mediated downregulation of TC21 sensitizes esophageal cancer cells to cisplatin

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World Journal of Gastroenterology 2012年第31期18卷 4127-4135页

作者： Md.Raghibul Hasan Shyam Singh chauhan Rinu Sharma Ranju Ralhan Department of Biochemistry All India Institute of Medical SciencesNew Delhi 110029India Department of Biotechnology School of BiotechnologyGuru Gobind Singh Indraprastha UniversityNew Delhi 110075India Department of Otolaryngology-Head and Neck Surgery Joseph and Mildred Sonshine Family Centre for Head and Neck DiseasesMount Sinai HospitalTorontoON M5G 1X5Canada Department of Pathology and Laboratory Medicine Alex Simona Shnaider Laboratory for Molecular OncologyMount Sinai HospitalTorontoON M5G 1X5Canada

AIM： To determine the functional significance of TC21 in esophageal squamous cell carcinoma （ESCC）. METHODS： TC21 siRNA transfection was carried out using Hyperfectamine to knock down TC21, and tran- scripts were analyzed by reverse transcription-poly- merase chain reaction and protein by Western *** demonstrated the effect of TC21 downregulation of cell signaling in esophageal cancer cells by assess- ing the phosphorylation status of its downstream tar- gets, phosphoinositide 3-kinase （PI3K）, phosphatase and tensin homolog （PTEN）, protein kinase B （pAl〈t）, nuclear factor-KB （NF-~B） and cyclinD1 using specific antibodies. Cell survival analysis after cisplatin treat- ment was carried out by cell viability assay and cell cycle analysis using flow cytometry. RESULTS： TC21 knockdown in human ESCC cell line TEl3 cells, showed only a marginal increase （14.2%） in cell death compared with control cells. The expres- sions of the signaling proteins PI3K and pAkt, transcrip- tion factor NF-KB, and cell cycle protein cyclin D1 were markedly decreased in response to TC21 downregula- tion, whereas the level of pPTEN, an antagonist of PI3K, was increased. In addition, we evaluated the potential of TC21 as a putative target for sensitizing ESCC cells to the chemotherapeutic agent cisplatin. Increased cell death （38.4%） was observed in cells treated with cis- platin after TC21 knockdown compared with cells which were treated with cisplatin alone （20% cell death）. CONCLUSION： Results suggest that TC21 mediates its effects via the PI3K-Akt pathway, NF-KB and cyclin D1, and enhances chemoresistance in esophageal cancer cells.

关键词： TC21 Esophageal squamous cell carci-noma siRNA Cisplatin Chemosensitivity

Comparative Multivariate Analysis of Codon and Amino Acid Usage in Three Leishmania Genomes

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Genomics, Proteomics & Bioinformatics 2011年第6期9卷 218-228页

作者： Nutan chauhan Ambarish Sharan Vidyarthi Raju Poddar Department of Biotechnology Birla Institute of TechnologyMesra Ranchi-835215 India

Multivariate analysis of codon and amino acid usage was performed for three Leishmania species, including L. donovani, L. infantum and L. major. It was revealed that all three species are under mutational bias and translational selection. Lower GC12 and higher GC3s in all three parasites suggests that the ancestral highly expressed genes （HEGs）, compared to lowly expressed genes （LEGs）, might have been rich in AT-content. This also suggests that there must have been a faster rate of evolution under GC-bias in LEGs. It was observed from the esti- mation of synonymous/non-synonymous substitutions in HEGs that the HEG dataset of L. donovani is much closer to L. major evolutionarily. This is also supported by the higher ds value as compared to ds between L. donovani and L. major, suggesting the conservation of synonymous codon positions between these two species and the role of translational selection in shaping the composition of protein-coding genes.

关键词： Leishmania relative synonymous codon usage multivariate analysis hydropathy aromaticity

Assessment of a fuzzy logic based MRAS observer used in a photovoltaic array supplied AC drive

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Frontiers in Energy 2014年第1期8卷 81-89页

作者： Bhavnesh KUMAR Yogesh K chauhan Vivek SHRIVASTAVA School of Engineering Gautam Buddha University Greater Noida201310 India Electrical Engineering Department National Institute of Technology Delhi Delhi 110077 India

In this paper a fuzzy logic （FL） based model reference adaptive system （MRAS） speed observer for high performance AC drives is proposed. The error vector computation is made based on the rotor-flux derived from the reference and the adaptive model of the induction motor. The error signal is processed in the proposed fuzzy logic controller （FLC） for speed adaptation. The drive employs an indirect vector control scheme for achieving a good closed loop speed control. For powering the drive system, a standalone photovoltaic （PV） energy source is used. To extract the maximum power from the PV source, a constant voltage controller （CVC） is also proposed. The complete drive system is modeled in MATLAB/Simulink and the performance is analyzed for different operating conditions.

关键词： induction motor drive fuzzy logic (FL)control model reference adaptive system (MILAS) photo-voltaic (PV) array vector control