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synthesis of few layer single crystal graphene grains on platinum by chemical vapour deposition

Progress in Natural science:Materials International 2015年第4期25卷 291-299页

作者： s.karamat s.sonu?en ü.?elik Y.Uysall? E.?zg?nül A.Oral Department of Physics Middle East Technical University COMsATs Institute of Information Technology Faculty of Engineering and Natural sciences Sabanc? University Nano Magnetics Instruments Ltd.

The present competition of graphene electronics demands an ef fi cient route which produces high quality and large area graphene. Chemical vapour deposition technique, where hydrocarbons dissociate in to active carbon species and form graphene layer on the desired metal catalyst via nucleation is considered as the most suitable method. In this study, single layer graphene with the presence of few layer single crystal graphene grains were grown on Pt foil via chemical vapour deposition. The higher growth temperature changes the surface morphology of the Pt foil so a delicate process of hydrogen bubbling was used to peel off graphene from Pt foil samples with the mechanical support of photoresist and further transferred to si O2/si substrates for analysis. Optical microscopy of the graphene transferred samples showed the regions of single layer along with different oriented graphene domains. Two type of interlayer stacking sequences, Bernal and twisted, were observed in the graphene *** presence of different stacking sequences in the graphene layers in fl uence the electronic and optical properties; in Bernal stacking the band gap can be tunable and in twisted stacking the overall sheet resistance can be reduced. Grain boundaries of Pt provides low energy sites to the carbon species, therefore the nucleation of grains are more at the boundaries. The stacking order and the number of layers in grains were seen more clearly with scanning electron microscopy. Raman spectroscopy showed high quality graphene samples due to very small D peak. 2D Raman peak for single layer graphene showed full width half maximum(FWHM) value of 30 cm-1. At points A, B and C, Bernal stacked grain showed FWHM values of 51.22, 58.45 and 64.72 cm-1, while twisted stacked grain showed the FWHM values of 27.26, 28.83 and 20.99 cm-1,respectively. FWHM values of 2D peak of Bernal stacked grain showed an increase of 20–30 cm-1 as compare to single layer graphene which showed its dispersive natu

关键词： Chemical vapour deposition Graphene hexagonal crystals Bernal stacking Twisted stacking Grain boundaries and hydrogen bubbling

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Graphene/srTiO3 hetero interface studied by X-ray photoelectron spectroscopy

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Progress in Natural science:Materials International 2016年第4期26卷 422-426页

作者： s.karamat C.Ke U.Y.Inkaya Rizwan Akram Ilker Yildiz s.shah Zaman A.Oral Department of Physics Middle East Technical University COMsATs Institute of Information Technology Microelectronics Centre School of Electrical and Electronic Engineering Nanyang Technological University Department of Electrical Engineering College of Engineering Qassim University

The present paper focuses on study of graphene and strontium titanate（srTiO3or sTO） interface. An ambient pressure chemical vapour deposition（AP-CVD） setup is used to grow graphene on sTO（110）substrates in the presence of methane, argon and hydrogen gases at 1000 °C for 4 h. Raman spectroscopy measurements confirm the presence of graphene on sTO substrates due to the existence of typical D and G peaks referring to graphene. These characteristic peaks are missing in the spectrum for bare substrates.X-ray photoelectron spectroscopy（XPs） is carried out for elemental analysis of samples, and study their bonding with sTO substrates. We employed the valence band spectrum to calculate the valence band offset（VBO） and conduction band offset（CBO） at the G-sTO interface. Also, we present an energy band diagram for Bi-layer and ABC（arranging pattern of carbon layers） stacked graphene layers.

关键词： Chemical vapour deposition X-ray photoelectron spectroscopy Raman spectroscopy Graphene Valence band maximum

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structural, elemental, optical and magnetic study of Fe doped ZnO and impurity phase formation

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Progress in Natural science:Materials International 2014年第2期24卷 142-149页

作者： s.karamat R.s.Rawat P.Lee T.L.Tan R.V.Ramanujan Natural science and science Education National Institute of Education Nanyang Technological University COMsATs Institute of Information Technology Department of Physics Middle East Technical University school of Material science and Engineering Nanyang Technological University Nanyang Avenue

We have prepared a series of(ZnO)1-x(Fe2O3)x≤0.10bulk samples with various concentrations of Fe dopant by ball milling and investigated their structural, compositional, optical and magnetic properties by means of X-ray diffraction(XRD), X-ray photoelectron spectroscopy(XPs),Raman spectrometer and vibrating sample magnetometer(VsM), respectively. Information about different impurity phases was obtained through Rietveld refinements of XRD data analysis. XPs results showed different valence states(Fe2+ tand Fe3+) supported by shaking satellite peaks in samples. With increasing Fe doping percentage, the crystal quality deteriorated and a shift of E2 low band(characteristic of ZnO) has been observed in Raman spectra. Energy band gap estimated from reflectance UV–vis spectroscopy showed shift for all bulk samples. The magnetic behavior was examined using a vibrating sample magnetometer(VsM), indicating ferromagnetic behavior at room temperature(300 K). The effective magnetic moment per Fe atom decreases with increase in doping percentage which indicates that ferromagnetic behavior arises from the substitution of Fe ions in the ZnO lattice.

关键词： Fe doped ZnO Dilute magnetic semiconductor Rietveld refinements X-ray spectroscopy Band gap Magnetic moment

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Genetic regulators of leaf size in Brassica crops

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Horticulture Research 2021年第1期8卷 1581-1591页

作者： Umer karamat Xiaoxue sun Na Li Jianjun Zhao state Key Laboratory of North China Crop Improvement and Regulation Key Laboratory of Vegetable Germplasm Innovation and Utilization of HebeiCollaborative Innovation Center of Vegetable Industry in HebeiCollege of HorticultureHebei Agricultural University071000 BaodingChina

Leaf size influences plant development and biomass and is also an important agricultural trait in Brassica crops,in which leaves are the main organ produced for *** size is determined by the coordinated regulation of cell proliferation and cell expansion during leaf development,and these processes are strictly controlled by various integrated signals from the intrinsic regulatory network and the growth *** the molecular mechanism of leaf size control is a prerequisite for molecular breeding for crop improvement *** research on leaf size control is just beginning in Brassica,recent studies have identified several genes and QTLs that are important in leaf size *** genes have been proposed to influence leaf growth through different pathways and mechanisms,including phytohormone biosynthesis and signaling,transcription regulation,small RNAs,and *** this review,we summarize the current findings regarding the genetic regulators of leaf size in Brassica and discuss future prospects for this research.

关键词： crops breeding size

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structural,electrical,dielectric and magnetic properties of Mn-Nd substituted CoFeO3 nano sized multiferroics

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Progress in Natural science:Materials International 2016年第4期26卷 325-333页

作者： Abdul Aziz E.Ahmed Muhammad Naeem Ashiq Muhammad Azhar Khan Nazia karamat Irshad Ali Department of Physics Bahauddin Zakariya University Institute of Chemical sciences Bahauddin Zakariya University Department of Physics The Islamia University of Bahawalpur Institute of Chemical sciences Bahauddin Zakariya University

A series of Mn x Co1-xFe1-yNdyO3（where x=0.0–1.0 & y=0.0–0.1） multiferroic nanocrystals was synthesized via sol-gel auto-combustion technique. The structure was confirmed by X-ray diffraction（XRD）while morphology was investigated by scanning electron microscopy（sEM）. The electrical resistivity was observed to increase from 2.14 * 10～7 to 8.77 * 10～9 Ω-cm and activation energy was found to increase from 0.64 to 0.75 e V, while the drift mobility decreased from 4.75 * 10-13to 1.27 * 10-15cm2V-1s-1by the substitution of Mn and Nd contents. The dielectric constant, dielectric loss and dielectric loss factor decrease with frequency and Mn-Nd contents. The saturation magnetization was increased from 34 to 70 emu g-1while the coercivity decreased from 705 to 262 Oe with the increase of *** increase in electrical resistivity and saturation magnetization while decrease in dielectric parameters and coercivity make these nanomaterials suitable for applications in microwave devices and longitudinal magnetic recording media.

关键词： Nanostructured materials XRD Dielectric properties Electrical properties Magnetic properties

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Introducing nitazoxanide as a promising alternative treatment for symptomatic to metronidazole-resistant giardiasis in clinical isolates

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Asian Pacific Journal of Tropical Medicine 2016年第9期9卷 866-871页

作者： Tahereh Mikaeili Galeh Abdolhassan Kazemi Mahmoud Mahami-Oskouei Behzad Baradaran Adel spotin seddigheh sarafraz Majid karamat Immunology Research Center Tabriz University of Medical Sciences Department of Parasitology and Mycology Faculty of MedicineTabriz University of Medical Sciences East Azerbaijan Province Health Center Tabriz Health Center

Objective:To identify the frequencies(F) of ferredoxin and nitroreductase mutations were identified on Iranian clinical isolates of Giardia lamblia in order to predict whether the nitazoxanide can be prescribed as suitable drug for symptomatic to metronidazoleresistant ***:Forty Giardia lamblia isolates as of 38 symptomatic and two metronidazole-resistant patients were collected from *** were extracted and amplified by targeting ferredoxin and Gl NR *** amplicons were directly sequenced to determine gene ***:The various amino acid substitutions(F:20%,Haplotype diversity:0.891,Tajima's D:-0.44013) were identified by analyzing ferredoxin gene in four symptomatic and two resistant ***,two haplotypes(F:5%,HD:0.345; Tajima's D:0.77815) characterized in metronidazole-resistant isolates of Gl NR,however,no point mutations was found in symptomatic ***:Non-synonymous mutations of ferredoxin oxidoreductase gene reduce translational regulatory protein's binding affinity which concludes reduction of ferredoxin expression and its *** leads to decrease in metronidazole drug delivery into the *** in these isolates may lead to their resistance to *** to low synonymous mutations of Gl NR demonstrates that nitazoxanide can be prescribed as promising alternative treatment for symptomatic to metronidazole-resistant giardiasis in Iranian clinical isolates.

关键词： Giardia lamblia Ferredoxin oxidoreductase Nitroreductase Nitazoxanide Metronidazole

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Fast tracking alien gene discovery by molecular markers in a late flowering Chinese cabbage-cabbage translocation line‘AT7–4'

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Horticultural Plant Journal 2023年第1期9卷 89-97页

作者： Hui Li Aixia Gu Daling Feng Na Li Rui Yang Xinpei Zhang shuangxia Luo Umer karamat Qianyun Wang shuxin Xuan Xueping Chen Yin Lu Yanhua Wang shuxing shen Jianjun Zhao state Key Laboratory of North China Crop Improvement and Regulation Key Laboratory of Vegetable Germplasm Innovation and Utilization of HebeiCollaborative Innovation Center of Vegetable Industry in HebeiBaodingHebei 071000China College of Horticulture Hebei Agricultural UniversityBaodingHebei 071000China College of Life science Hebei Agricultural UniversityBaodingHebei 071000China

Flowering time is an important agronomic trait of Chinese cabbage with late flowering being a primary breeding *** our previous work,we obtained Chinese cabbage-cabbage translocation lines that contained several beneficial cabbage ***-specific molecular markers show that these genes were coming from chromosome C01 of *** this study,we investigated the inheritance of flowering time in a couple of translocation lines and analyzed the transmission rate of molecular markers in the ***,we obtained the late flowering Chinese cabbage-cabbage translocation line‘AT7–4’in which the flowering time was later than that of‘85–1’by about 7 days under 4-week *** on previous studies of the genomes of Chinese cabbage and cabbage,we located the cabbage-specific molecular markers that were closely linked at the top of the chromosome A01 in the F2mapping population generated by self-crossing F1s derived from a cross between the translocation line‘AT7–4’and Chinese cabbage‘14–36’.Five flowering-related genes in the alien fragment were found by functional annotation and their molecular markers were *** study lays the foundation for the future improvement of Chinese cabbage varieties using A-C translocation lines.

关键词： Chinese cabbage Translocation line Alien gene Molecular marker Late flowering

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