Weak field NMR and double resonance spectrometers are mostly homemade. In this work, some electronic units of such a spectrometer operating at 1.437 mT were designed and realized by includ­ing new integrated circuits: an audio generator, digital sweep generator, digital additional field and delay unit, Quartz generator, NMR detector(Q-meter), AF-narrowband amplifier, phase shifter and phase sensitive detector.

TurkeyNuclear magnetic resonance and dynamic nuclear polarization experiments were performed to study suspensions of asphaltene in the fluorocarbons at a low magnetic field of 1.53 mT, at room temperature. The asphaltene was extracted from MC800 liquid asphalt, which was of Heavy Iran origin. The elemental composition and the surface morphology of the asphaltene were determined by scanning electron microscopy and energy dispersive X-ray analysis. Intermolecular spin-spin interactions occur between nuclear spins of hydrogen in the solvent medium and the free electron spins in the asphaltene micelles. The electron paramagnetic resonance spectrum of the asphaltene was obtained and the saturation experiments were applied to the samples prepared in vacuum. The main 1 H DNP parameters were listed. Chemical composition and molecular structure of the asphaltene were analyzed. Scanning electron microscope images have shown that asphaltenes are constituted of agglomerated particles and smooth surfaces. Energy dispersive X-ray analysis has shown that the most abundant element is carbon. IntroductionAsphaltenes, which are a part of petroleum, are regarded to be polar species, have larger aromatic structures and are containing alkyl chains, heteroatoms (such as O, S and N) and some metals [1]. Asphaltenes have unpaired electrons, which are observed using the electron spin resonance (ESR) experiments in crude petroleum [2].Dynamic nuclear polarization (DNP) utilizes the liquid state interaction between nuclei and unpaired electron spins to generate an increased nuclear polarization upon the saturation of ESR transitions of the radicals. The maximum DNP enhancement of the NMR signal is given by the electron-to-nuclear gyromagnetic ratios γ e /γ n . This ratio for proton spin is 660. In this study, the nuclear spins are the proton spins, which are the 1 H nuclei of the solvent medium and the electron spins belong to the free electrons on the asphaltene micelles. The unpaired electrons were delocalized on the incomplete carbon bonds of the condensed aromatic structure of the asphaltene particles [3]. By DNP method we have revealed dipolar interaction between hydrogen atoms of the solvent and unpaired electrons of colloidal asphaltene. Electron spin saturation and DNP enhancements have been obtained and DNP parameters determined in low magnetic field. Chemical composition and morphology of MC800 asphaltene were investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray (EDX) analysis.

Capacitors with high voltage and capacity values are used in most induction coilguns that are designed and constructed. The fact that capacitors are quite bulky and slow in energy transfer and how a coilgun can be made without using capacitors is the study subject of this article. Two and four coil gun samples were made to find the essential components of an electric gun, and the results are reported in this article. The accuracy of the results is also confirmed by FEMM analysis for these models. The harmony of experimental and theoretical results shows that smaller and low cost portable electrical weapons can be a powerful alternative to firearms in the future.

In this study, Overhauser effect (OE) type of dynamic nuclear polarization (DNP) experiments were performed to study suspensions of MC800 asphaltene in bromopentafluorobenzene, chloropentafluorobenzene and hexafluorobenzene aromatic solvents. The experiments were performed at a low field of 1.53 mT in a double-resonance nuclear magnetic resonance (NMR) spectrometer. In this technique the nuclei of diffusing solvent molecules and the unpaired electron existing on the asphaltene micelles interact magnetically. The DNP parameters were determined. Additionally, the interactions between 19 F nuclei of the solvent and the electrons delocalized on the asphaltene are interpreted. The highest enhancement factor value (5.90) was obtained for the hexafluorobenzene solvent medium, because between these, hexafluorobenzene has the highest fluorine atom number. The solvent molecules attach to the colloidal asphaltene particles for a very short time forming complexes and making scalar interaction. Morphologies of asphaltene surfaces depending on the solvent effects were observed by using scanning electron microscopy (SEM).

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Magnetic imaging systems used today are quite expensive and are generally used for medical purposes. Apart from this purpose, there are many scientific fields of study whose internal structure is desired to be displayed. Especially in science, different from the techniques used to understand the internal structure of matter, magnetic imaging techniques are also needed. Therefore, the interest in more useful and smaller magnetic imaging systems is increasing. For this purpose, studies on magnetic particle imaging and magnetic resonance imaging techniques have gained momentum. The magnetic resonance imaging technique, which is one of the magnetic imaging systems based on the NMR phenomenon, has passed through numerous stages and has become smaller and more useful. This study examines the basic components of the NMR images made in the earth's magnetic field for different liquids, the T1 and T2 proton relaxation parameters, and the technique of the obtained two-dimensional images with the EFNMR system.

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This study devotes to the design and fabrication of a spin coating equipment using locally available materials for the deposition of uniform thin films on several substrates and also the production of organic light emitting diodes (OLEDs) using this home-made device. The equipment consists of a brushed direct current (BDC) motor with high speed, chuck (substrate holder) and regulated power supply. The system has manual control, wide spin speed ranging from 500 to 6500 revolutions per minute (rpm), spin speed stability and compact size. The spin speed stability has been determined by a tachometer against the spinning time. The performance of our equipment was tested for coating Poly (3,4-ethylene dioxythiophene)poly (styrene sulfonate) (PEDOT:PSS) polymer. Three different PEDOT:PSS thin films were successfully deposited on glass substrates that are standard products, using the spin speeds of 1000, 2000 and 3000 revolutions per minutes (rpm). Also, under similar experimental conditions, PEDOT:PSS films were prepared by a commercial spin coater. These two group samples have been characterized by optical and atomic force microscope (AFM) measurements and compared with each other. Furthermore, in order make an OLED, a multilayer system consisting of, in sequence, PEDOT:PSS, poly[2-methoxy-5-(2`-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV) and Tris (8-hydroxyquinolinato) Aluminium (Alq3) layers was fabricated on commercial indium tin oxide (ITO)/glass substrates using both our home-made and a commercial spin coater. The top layers of all samples were covered by the Al using thermal evaporation. The current-voltage (I-V) characteristics of OLED samples prepared by two different devices were examined. The obtained data showed that OLEDs could successfully be produced by our homemade spin coater.