STM

This paper introduces a successful approach for distinguishing abandoned luggage in surveillance recordings. We join short-and long-term foundation models to concentrate on closer view of objects, where every pixel in an information picture is named a 2 bit code. In this manner, we acquaint a structure with recognized static frontal areas in light of the worldly move of code designs, and to figure out if the applicant districts contain surrendered protests by breaking down the back-followed directions of baggage proprietors. The trial comes about acquired in light of video pictures from 2006 performance evaluation of tracking and surveillance, and 2007 advanced video and signal-based surveillance databases demonstrate that the proposed approach is successful for identifying relinquished gear, and that it outflanks past techniques.

Especialista em Ciências Penais pela PUC/MG Introdução Em abril de 2010 foi nos dada, pelo Professor Dr. Ricardo R. Berkman (durante curso realizado na Universidad de Buenos Aires -UBA), a tarefa de desenvolvermos, à partir de uma fonte imediata (ou primária), um trabalho que se relacionasse à História do Direito -ou, melhor dizendo, à um curto (porém importante) período temporal de um determinado local. Esta fonte deveria ser correspondente à região do autor do trabalho e, se possível, anterior à queda do governo militar. Em obediência ao primeiro requisito, a fonte deveria ser, então, correspondente à região de Minas Gerais, estado localizado na região sudeste do Brasil, e que faz fronteira com os estados de São Paulo, Rio de Janeiro, Espírito Santo, Bahia, Goiás e Mato Grosso do Sul.

This paper covers the design of a prototype for IoT and GPS enabled door lock system. The aim of this research is to design a door lock system that does not need manual input from user for convenience purpose while also remaining secure. The system primarily consists STM32L100 microcontroller as its core, TIP102 transistor that controls 12 V DC solenoid, and Xbee module to communicate with the smart home's host and receive status regarding user's GPS position. The system is tested by measuring the user's distance from the predetermined location using GPS coordinate captured by an Android application, which serves to test whether the system is able to operate as intended and measure the device's power usage. The test result shows that the device is able to work based on GPS coordinate data received, using 42.3 mA and 587 mA current in idle and active modes, respectively.

Keywords: Genetically modified organism (GMO) Soybean Polycarbonate (PC) microdevice Surface hydrophilic/hydrophobic modification Flow-through polymerase chain reaction (PCR) 35S promoter bar gene a b s t r a c t In this study, a polycarbonate (PC) microdevice functioning as a reactor for the polymerase chain reaction (PCR) was fabricated for rapid identification of genetically modified organisms (GMOs). The PC micro-device was fabricated by first modifying its surface with an amine-functionalized alkoxysilane, namely bis[3-(trimethoxysilyl)propyl]amine (bis-TPA), to obtain a hydrophilic surface. Coating of bis-TPA on PC was realized by forming a urethane linkage between the amine terminals of the bis-TPA with the car-bonate backbone of PC by aminolysis. This surface enabled the thermal bonding of two PC substrates at a relatively low temperature and atmospheric pressure, thereby maintaining the structure of the micro-channel in high resolution. Next, the surface of the microchannel was further treated with a fluorosilane, namely tridecafluoro-(1,1,2,2-tetrahydrooctyl)-triethoxysilane (FTES), to obtain a hydrophobic surface inside the microchannel. This modification was realized by the hydrolysis and subsequent condensation of the alkoxy terminals of both bis-TPA and FTES to form a robust siloxane (SieOeSi) bond. The hy-drophobic microchannel improved the PCR performance by stabilizing the fluid flow, particularly under heated conditions, when the flow-through PCR was conducted on a microdevice. Using the microdevice, the 35S promoter sequences and bar gene, which are commonly used for the identification of GMOs, were successfully amplified, resulting in the detection of 234 and 504 bp gene fragments for the 35S promoter sequences and 261 bp gene fragment for the bar gene from the genomic DNA extracted from the leaves of GM soybean. This process took approximately 30e35 min, which was approximately 3-fold faster than when using a conventional thermal cycler.

The present study aimed to identify predictors of one aspect of sign language acquisition, sign learning, in hearing nonsigners. Candidate predictors were selected based on the theory that the observed relationship between phonological short-term memory and L2 lexical learning is due in part to common perceptual-motor processes. Hearing nonsigning adults completed a sign learning task, three assessments of short-term memory for movements (movement STM)- two of which used sign-like stimuli-and two visuospatial STM tasks. The final sample included 103 adults, ranging between 18 and 33 years of age. All predictors were moderately to strongly correlated with the sign learning task and to each other. A series of regression analyses revealed that both movement and visuospatial STM uniquely contributed to the prediction of sign learning. These results suggest that perceptual-motor processes play a significant role in sign learning and raise questions about the role of phonological processing.

In this work, highly-resolved scanning tunneling microscopy images of graphite basal plane are obtained and theoretical computations are performed to explain the resolution of only half the atoms in STM images of graphite. Our experimental and computational findings indicate that the bright elliptical spots observed in trigonal STM images of graphite may not correspond to carbon positions but to π-states localized above alternate carbon–carbon bonds. This interpretation is based on STM experiments that suggest that the elliptical shape of the bright spots may not be a tip artifact and on simulated STM images of a graphite using orthorhombic unit cells that are in excellent agreement with experimentally obtained images.

Single atom/molecule manipulation with a scanning-tunneling-microscope (STM) tip is an innovative experimental technique of nanoscience. Using STM-tip as an engineering or analytical tool, artificial atomic-scale structures can be fabricated, novel quantum phenomena can be probed, and properties of single atoms and molecules can be studied at an atomic level. The STM manipulations can be performed by precisely controlling tip-sample interactions, by using tunneling electrons, or electric field between the tip and sample. In this article, various STM manipulation techniques and some of their applications based on the author's experience are described, and the impact of this research area on nanoscience and technology is discussed.

This article is an historical account of the indigenous development of one of the earliest scanning tunneling microscopes in India. It was fabricated in the Department of Physics at the University of Pune just a few years after it was first made in Europe. A series of scanning probe microscopes (SPMs) were made here subsequently – a process in which students played a major role. Over a period of two decades these SPMs were used to produce a series of scientific papers besides train- ing students in making, using and modifying the instruments and then pushing them to their limits. Importantly, junk markets, scrap materials, small time spring makers and second-hand dealers and traditional knowledge practices were all an integral part of this enterprise of ‘instrument-making’ and doing scientific research.
Keywords: History, innovation, scanning tunneling microscope, technological jugaad.

This paper covers the design of a prototype for IoT and GPS enabled door lock system. The aim of this research is to design a door lock system that does not need manual input from user for convenience purpose while also remaining secure. The system primarily consists STM32L100 microcontroller as its core, TIP102 transistor that controls 12 V DC solenoid, and Xbee module to communicate with the smart home's host and receive status regarding user's GPS position. The system is tested by measuring the user's distance from the predetermined location using GPS coordinate captured by an Android application, which serves to test whether the system is able to operate as intended and measure the device's power usage. The test result shows that the device is able to work based on GPS coordinate data received, using 42.3 mA and 587 mA current in idle and active modes, respectively.

A system for the fabrication of sharp metal tips with nanoscale diameter is designed and constructed. The fabrication of the tips is based on an electrochemical reaction between an anode and a cathode immersed in a chemical solution. The system is part of the project “Construction of a system of probe exploration by tunneling effect for nanoscalar measurement” of the group of research of Nanoscience of the Pontificia Universidad Javeriana.
Stainless plates are used as cathodes. A metallic wire of diameter between 0.1 and 1 mm is used as an anode. The wire or anode is each time aligned at the center of the cathodes and a voltage between the cathodes and the anode is supply from a power source. This voltage can be constant or variable
depending on the expected current between the cathodes and the anode. The electrochemical reaction takes place when the voltage is applied. A section of the wire corrodes creating a neck that gets thinner under the reaction. Eventually, the thickness of the neck is such that the part of the wire that is below the neck falls, the reaction stops and the neck becomes the tip itself. For the implementation of the described process, the system has divided in four different modules: mechanic, electrochemical, electronic and optic. All the modules permit jointly to visualize
the electrochemical reaction in real time and to obtain the values of the voltage and current between the anode and the cathode. The system has two modes of operation: automatic and manual, and it is possible to further implement a memory function that retain the voltage and current values for sampling time values of the process of carving.

Fourier transform scanning tunneling spectroscopy (FT-STS) measures the scattering of conduction electrons from impurities and defects, giving information about the electronic structure of both the host material and adsorbed impurities. We interpret such FT-STS measurements in terms of the quasiparticle interference (QPI), investigating the QPI due to magnetic impurities adsorbed on a range of representative non-magnetic host surfaces, and contrasting with the case of a simple scalar impurity or point defect. We demonstrate how the electronic correlations present for magnetic impurities markedly affect the QPI, showing e.g. a large intensity enhancement due to the Kondo effect, and universality at low temperatures/scanning-energies. The commonly-used joint density of states (JDOS) interpretation of FT-STS measurements is also considered, and shown to be insuffcient in many cases, including that of magnetic impurities.

The electrostatic confinement of massless charge carriers is hampered by Klein tunneling. Circumventing this problem in graphene mainly relies on carving out nanostructures or applying electric displacement fields to open a band gap in bilayer graphene. So far, these approaches suffer from edge disorder or insufficiently controlled localization of electrons. Here we realize an alternative strategy in monolayer graphene, by combining a homogeneous magnetic field and electrostatic confinement. Using the tip of a scanning tunneling microscope, we induce a confining potential in the Landau gaps of bulk graphene without the need for physical edges. Gating the localized states towards the Fermi energy leads to regular charging sequences with more than 40 Coulomb peaks exhibiting typical addition energies of 7-20 meV. Orbital split-tings of 4-10 meV and a valley splitting of about 3 meV for the first orbital state can be deduced. These experimental observations are quantitatively reproduced by tight binding calculations, which include the interactions of the graphene with the aligned hexagonal boron nitride sub-strate. The demonstrated confinement approach appears suitable to create quantum dots with well-defined wave function properties beyond the reach of traditional techniques.

The atomic structure of "pinwheel" TiO ∼1.2 ultrathin oxide (w-TiO-UTO) layer and its reaction with gold are studied by scanning tunneling microscopy (STM) imaging and density functional theory (DFT) calculations. The UTO film was formed as an encapsulation layer on the top facet (111) of stripe-like Rh nanoparticles supported on a TiO 2 (110) substrate. For proposing a structural model, the previous STM, photoelectron (XPS), and ion scattering spectroscopy (LEIS) results were also taken into account. DFT calculations were carried out within the generalized gradient approximation (GGA-PBE) in the frame of the Quantum Espresso code. A Rh(111) slab of four layers with a TiO 1.14 overlayer and a Rh−Ti−O stacking sequence were used. In the starting model, the ratio between hcp and fcc sites filled with Ti atoms was 1.54 (the same value for O atoms was 2.2) on the top of Rh layers. The simulation of the STM images of the relaxed structure was done following the Tersoff− Hamann approximation. The main structural characteristics obtained experimentally were successfully reproduced in the simulation results: (i) the chemical contrast appeared as a pinwheel structure and (ii) compared with an ideal hexagonal lattice, characteristic local distortions were found in the UTO film. In harmony with the experimental results, the DFT calculations of the adsorption of a single Au atom on a w-TiO-UTO layer indicated that there is a characteristic site preference within the unit cell of the UTO film. This feature was also experimentally demonstrated for the early stage of the deposition of Au at room temperature, suggesting a moderate template effect adjusted by the pinwheel structure. This work demonstrates clearly that the lack of the so-called "nanoholes" does not completely cancel the template effect because the periodic lattice strain in itself substitutes their role. Moreover, the weaker modulation of Au/TiO-UTO bond permits the formation of one atomic layer thick 2D gold nanoparticles at 300 K.

Corbels are cantilever with small shear span to depth ratio (a/d) projected from columns or walls to support precast members like beams, girders or dapped end beams. Shear friction (SF) method is used to analyze and design reinforced concrete (RC) corbels. Because of the small value of a/d, corbels are treated as deep beams. Using strut and tie modeling (STM), they can be analyzed. In both SF and STM, there are many parameters that affect the behavior of the corbels such as a/d, width (b), compressive strength of concrete (f'c), yield strength of reinforcement (fy), and horizontal to vertical load ratio (H/V). In the current study, according to ACI 318-14 provisions, the effect of these parameters were investigated using both SF and STM. It was found that the shear capacity increases by about 32.6%, 26.3% and 31.2% for SF and by about 54.1%, 50.4% and 30.9% for STM with increasing width, compressive strength, and yield strength by about (100-300) %, (15-35) % and (400-600) %, respectively. Whereas, shear capacity decreases by about 58.54% and 48.7% for SF and about 59.4% and 33.2% for STM with increasing a/d and H/V by about (0.1-1.9)% and (0-1)%, respectively. It was also seen that the results obtained by STM is more reliable than SF when compared with experimental works that were taken from literature.

The correlation between structural and chemical properties of bimetallic PtRu/Ru(0001) model catalysts and their modification upon stepwise annealing of a submonolayer Pt-covered Ru(0001) surface up to the formation of an equilibrated
Pt_x Ru_{1-x} /Ru(0001) monolayer surface alloy was investigated by scanning tunneling microscopy and by the adsorption of CO and D_2 probe molecules. Both temperature-programmed desorption and IR measurements demonstrate the influence of the surface structure on the adsorption properties of the bimetallic surface, which can be explained by changes of the composition of the adsorption ensembles (ensemble effects)
for D adsorption and by changes in the electronic interaction
(ligand effects, strain effects) of the metallic constituents for
CO and D adsorption upon alloy formation.

This brief tutorial is specifically written to assist the beginner users of STM32 boards in order to learn the fundamentals of how to activate and work with the (Digital-to-Analog Converter) DAC module. It is intended to show the different methods of using the DAC module on the STM32 boards with application to signal generation for system identification purposes. In this tutorial you will learn how to: 1) Download the STM32 software packages, 2) Compile ARM CMSIS 4.5.0 DSP library in STM32CubeIDE, 3) Configure and utilize TIM / DAC / GPIO modules of the microcontroller, 4) Generate different wave forms for system identification applications, 5) Program NUCLEO-F746ZG in STM32CubeIDE using C programming language, 6) Excite the dynamics of a mechatronics system using the developed algorithms.

O tema dessa artigo e a Justica Militar Brasileira no periodo de 1965-1969. Analisa-se a atuacao de Peri Constant Bevilaqua no Superior Tribunal Militar (STM), com enfase na posicao por ele assumida diante da realidade juridico-politica da ditadura militar.  Palavras chave: Justica Militar; Superior Tribunal;  Peri Constant Bevilaqua

The photophysical properties of silicon semiconductor nanocrystals (SiNCs) are extremely sensitive to the presence of surface chemical defects, many of which are easily produced by oxidation under ambient conditions. The diversity of chemical structures of such defects and the lack of tools capable of probing individual defects continue to impede understanding of the roles of these defects in SiNC photophysics. We use scanning tunneling spectroscopy to study the impact of surface defects on the electronic structures of hydrogen-passivated SiNCs supported on the Au(111) surface. Spatial maps of the local electronic density of states (LDOS) produced by our measurements allowed us to identify locally enhanced defect-induced states as well as quantum-confined states delocalized throughout the SiNC volume. We use theoretical calculations to show that the LDOS spectra associated with the observed defects are attributable to Si−O−Si bridged oxygen or Si−OH surface defects.

Highlights  An original growth of Mg2Si ultra-thin silicide films is reported  Growth mechanisms, stability, and decomposition processes of such nanometric silicide thin films are described.  Decomposition of the Mg2Si silicide under O2 atmosphere through the formation of a stable MgO thin film is also reported. 2 nevertheless, continuous 2D silicide films are formed with a volcano shape surface topography characteristic up to 4 Mg MLs. Due to high reactivity between magnesium and oxygen species, the thermal oxidation process in which a thin Mg2Si film is fully decomposed (0.75 eV band gap) into a magnesium oxide layer (6-8 eV band gap) is also reported.

A new perspective in the design of reinforced-concrete pile caps is proposed in this paper, where the conventional approach leading to a reinforcing mesh is replaced by modelling the cap as a strut-and-tie system, in agreement with the strut-and-tie model, STM proposed by several design codes, ACI 318 included. Twelve RC pile-cap specimens were designed and manufactured. In the first group of 4 specimens the caps rest on two piles (Group A, axis-to-axis distance 300 mm), while in the second and third groups the piles are three and four, respectively (Groups B and C, axis-to-axis distance 400 mm). In each group, the first and third specimens were designed according to the traditional sectional method (reference specimens, with constant depth and lateral shoulders), while the design of the second and fourth specimens was based on the strut-and-tie method (no lateral shoulders; no corners opposite to the piles). Needless to say, the nominal design load was the same within each group. The tests clearly show that cap design based on strut-and-tie systems brings in a sizable reduction in terms of reinforcement amount and cost, accompanied by a less pronounced but still sizable extra bearing capacity.

The atomic structure of “pinwheel” TiO∼1.2 ultrathin
oxide (w-TiO-UTO) layer and its reaction with gold are studied by
scanning tunneling microscopy (STM) imaging and density functional
theory (DFT) calculations. The UTO film was formed as an
encapsulation layer on the top facet (111) of stripe-like Rh nanoparticles
supported on a TiO2(110) substrate. For proposing a structural model,
the previous STM, photoelectron (XPS), and ion scattering spectros-
copy (LEIS) results were also taken into account. DFT calculations were
carried out within the generalized gradient approximation (GGA-PBE)
in the frame of the Quantum Espresso code. A Rh(111) slab of four
layers with a TiO1.14 overlayer and a Rh−Ti−O stacking sequence were
used. In the starting model, the ratio between hcp and fcc sites filled with Ti atoms was 1.54 (the same value for O atoms was
2.2) on the top of Rh layers. The simulation of the STM images of the relaxed structure was done following the Tersoff−
Hamann approximation. The main structural characteristics obtained experimentally were successfully reproduced in the
simulation results: (i) the chemical contrast appeared as a pinwheel structure and (ii) compared with an ideal hexagonal lattice,
characteristic local distortions were found in the UTO film. In harmony with the experimental results, the DFT calculations of
the adsorption of a single Au atom on a w-TiO-UTO layer indicated that there is a characteristic site preference within the unit
cell of the UTO film. This feature was also experimentally demonstrated for the early stage of the deposition of Au at room
temperature, suggesting a moderate template effect adjusted by the pinwheel structure. This work demonstrates clearly that the
lack of the so-called “nanoholes” does not completely cancel the template effect because the periodic lattice strain in itself
substitutes their role. Moreover, the weaker modulation of Au/TiO-UTO bond permits the formation of one atomic layer thick
2D gold nanoparticles at 300 K.

El presente paper se basa en la tesina de seminario titulada "Diseño de una Red SDH para Dar Servicios de dos STM-1 y Dotar a un Call Center con 8 E1 Utilizando una Red Metro Ethernet con Tecnología TDMoIP" con el fin de dar una perspectiva técnica ante el diseño de una red basada en SDH y constatar que los criterios y decisiones técnicas son complemento de las decisiones financieras de una empresa.

In this paper, we discuss the possibility of transmitting synchronous digital hierarchy (SDH) signals through two-link nonlinear satellite channels. Transmitting such high bit rate signals through standard 54 MHz or 36 MHz transponder bandwidth requires the use of high-level modulation schemes. The techniques and technologies needed to make the use of 16-ary QAM and 64-ary QAM transmissions feasible for future satellite communication systems are examined. We show that it is possible to transmit a synchronous transport modulelevel 1 (STM-1) signal through a standard 54 or 36 MHz transponder bandwidth using 16-ary QAM or 64-ary QAM transmission, respectively, for the 6 / 4 GHz band. However, for higher frequency bands, due to high fade margins needed to achieve the high availability and performance for SDH systems, it is not practical to transmit the STM-1 signal through such standard transponder bandwidths.

This paper covers the design of a prototype for IoT and GPS enabled door lock system. The aim of this research is to design a door lock system that does not need manual input from user for convenience purpose while also remaining secure. The system primarily consists STM32L100 microcontroller as its core, TIP102 transistor that controls 12 V DC solenoid, and Xbee module to communicate with the smart home's host and receive status regarding user's GPS position. The system is tested by measuring the user's distance from the predetermined location using GPS coordinate captured by an Android application, which serves to test whether the system is able to operate as intended and measure the device's power usage. The test result shows that the device is able to work based on GPS coordinate data received, using 42.3 mA and 587 mA current in idle and active modes, respectively.

The atomic structure of "pinwheel" TiO ∼1.2 ultrathin oxide (w-TiO-UTO) layer and its reaction with gold are studied by scanning tunneling microscopy (STM) imaging and density functional theory (DFT) calculations. The UTO film was formed as an encapsulation layer on the top facet (111) of stripe-like Rh nanoparticles supported on a TiO 2 (110) substrate. For proposing a structural model, the previous STM, photoelectron (XPS), and ion scattering spectroscopy (LEIS) results were also taken into account. DFT calculations were carried out within the generalized gradient approximation (GGA-PBE) in the frame of the Quantum Espresso code. A Rh(111) slab of four layers with a TiO 1.14 overlayer and a Rh−Ti−O stacking sequence were used. In the starting model, the ratio between hcp and fcc sites filled with Ti atoms was 1.54 (the same value for O atoms was 2.2) on the top of Rh layers. The simulation of the STM images of the relaxed structure was done following the Tersoff− Hamann approximation. The main structural characteristics obtained experimentally were successfully reproduced in the simulation results: (i) the chemical contrast appeared as a pinwheel structure and (ii) compared with an ideal hexagonal lattice, characteristic local distortions were found in the UTO film. In harmony with the experimental results, the DFT calculations of the adsorption of a single Au atom on a w-TiO-UTO layer indicated that there is a characteristic site preference within the unit cell of the UTO film. This feature was also experimentally demonstrated for the early stage of the deposition of Au at room temperature, suggesting a moderate template effect adjusted by the pinwheel structure. This work demonstrates clearly that the lack of the so-called "nanoholes" does not completely cancel the template effect because the periodic lattice strain in itself substitutes their role. Moreover, the weaker modulation of Au/TiO-UTO bond permits the formation of one atomic layer thick 2D gold nanoparticles at 300 K.

The electrostatic confinement of massless charge carriers is hampered by Klein tunneling. Circumventing this problem in graphene mainly relies on carving out nanostructures or applying electric displacement fields to open a band gap in bilayer graphene. So far, these approaches suffer from edge disorder or insufficiently controlled localization of electrons. Here we realize an alternative strategy in monolayer graphene, by combining a homogeneous magnetic field and electrostatic confinement. Using the tip of a scanning tunneling microscope, we induce a confining potential in the Landau gaps of bulk graphene without the need for physical edges. Gating the localized states towards the Fermi energy leads to regular charging sequences with more than 40 Coulomb peaks exhibiting typical addition energies of 7-20meV. Orbital splittings of 4-10meV and a valley splitting of about 3meV for the first orbital state can be deduced. These experimental observations are quantitatively reproduced by...

One of the intriguing characteristics of honeycomb lattices is the appearance of a pseudo-magnetic field as a result of mechanical deformation. In the case of graphene, the Landau quantization resulting from this pseudo-magnetic field has been measured using scanning tunneling microscopy. Here we show that a signature of the pseudo-magnetic field is a local sublattice symmetry breaking observable as a redistribution of the local density of states. This can be interpreted as a polarization of graphene's pseudospin due to a strain induced pseudo-magnetic field, in analogy to the alignment of a real spin in a magnetic field. We reveal this sublattice symmetry breaking by tunably straining graphene using the tip of a scanning tunneling microscope. The tip locally lifts the graphene membrane from a SiO$_2$ support, as visible by an increased slope of the $I(z)$ curves. The amount of lifting is consistent with molecular dynamics calculations, which reveal a deformed graphene area unde...

A new model description and type classification carried out on its base of a wide variety of practical hysteresis loops are suggested. An analysis of the loop approximating function was carried out; the parameters and characteristics of the model were defined – coersitivity, remanent polarization, value of hysteresis, spontaneous polarization, induced piezocoefficients, value of saturation, hysteresis losses of energy per cycle. It was shown that with piezomanipulators of certain hysteresis loop types, there is no difference in heat production. The harmonic linearization coefficients were calculated, and the harmonically linearized transfer function of a nonlinear hysteresis element was deduced. The hysteresis loop type was defined that possesses minimum phase shift. The average relative approximation error of the model has been evaluated as 1.5%–6% for real hysteresis loops. A procedure for definition of the model parameters by experimental data is introduced. Examples of using the results in a scan unit of a scanning tunneling microscope for compensation of raster distortion are given.

The ability to position a sharp probe in close proximity to a sample while the surface is illuminated by synchrotron x-rays opens a path to localized spectroscopy and imaging with chemical and magnetic contrast. We have employed a scanning tunneling microscope for the local study of synchrotron x-ray magnetic circular dichroism of micron-sized NiFe rings. Spectra have been obtained by an insulator-coated tip positioned about 200 nm over the sample surface. A negative sample bias is required in order to enhance the dichroism signal at the tip.

The early stage of thymine (Thy) adsorption on Si(111)7×7 surface is studied with scanning tunneling microscopy (STM) and density functional theory (DFT)-based computational method. Bright protrusions corresponding to the adsorbed thymine molecules are observed in both empty-state and filled-state STM images. These bright protrusions in the empty-state images exhibit three different degrees [lower (L), medium (M), and higher (H)] of intensities. The L and M protrusions are found on the adatom−restatom pairs in the 7 × 7 unit cell, indicating bidentate configurations for Thy adsorption. A free Thy molecule has been found to interact with the Si surface by a two-step process: Thy first undergoes keto−enol tautomerization to form the more stable dienol tautomer, which then binds to the Si adatom−restatom pair via the [4 + 2] cycloaddition reaction, leading to two different adproducts. Our DFT/ B3LYP/6-31++G(d,p) calculations show three plausible cycloaddition products, with the 1,4-cyclohexadiene adproduct being more stable than 3,6-and 2,5-cyclohexadienes. Our calculations also suggest the viability of formation of a Thy molecule hydrogen-bonded with the bidentate Thy adproducts already on the surface. Statistical analysis for three different exposures of Thy on the 7 × 7 surface reveals that the L protrusion has the highest relative surface concentration (80%), with the M (16%) and H features (4%) being significantly less popular. These results lead us to attribute the L and M protrusions to the 1,4-and the 3,6-cycloaddition products, respectively, with the least popular H protrusion assigned to a Thy molecule hydrogen-bonded to the bidentate Thy, all attached to an adatom−restatom pair. The observation of [4 + 2] cycloaddition products on the Si surface confirms the formation of precursor dienol Thy tautomer. This surface-mediated two-step reaction pathway for Thy is unique for surfaces, in contrast to keto−enol tautomerization that is mainly observed in the solution phase either by acid-or base-catalyzed pathways. Our STM study coupled with our separate XPS work have demonstrated that this type of tautomerization can also be observed on Si surfaces, and this can initiate the subsequent cycloaddition reactions of Thy molecule with the surface.

ABSTRACT In this study, a polycarbonate (PC) microdevice functioning as a reactor for the polymerase chain reaction (PCR) was fabricated for rapid identification of genetically modified organisms (GMOs). The PC microdevice was fabricated by first modifying its surface with an amine-functionalized alkoxysilane, namely bis[3-(trimethoxysilyl)propyl]amine (bis-TPA), to obtain a hydrophilic surface. Coating of bis-TPA on PC was realized by forming a urethane linkage between the amine terminals of the bis-TPA with the carbonate backbone of PC by aminolysis. This surface enabled the thermal bonding of two PC substrates at a relatively low temperature and atmospheric pressure, thereby maintaining the structure of the microchannel in high resolution. Next, the surface of the microchannel was further treated with a fluorosilane, namely tridecafluoro-(1,1,2,2-tetrahydrooctyl)-triethoxysilane (FTES), to obtain a hydrophobic surface inside the microchannel. This modification was realized by the hydrolysis and subsequent condensation of the alkoxy terminals of both bis-TPA and FTES to form a robust siloxane (Si-O-Si) bond. The hydrophobic microchannel improved the PCR performance by stabilizing the fluid flow, particularly under heated conditions, when the flow-through PCR was conducted on a microdevice. Using the microdevice, the 35S promoter sequences and bar gene, which are commonly used for the identification of GMOs, were successfully amplified, resulting in the detection of 234 and 504 bp gene fragments for the 35S promoter sequences and 261 bp gene fragment for the bar gene from the genomic DNA extracted from the leaves of GM soybean. This process took approximately 30-35 min, which was approximately 3-fold faster than when using a conventional thermal cycler.

The study investigated benefits which Basic school teachers in the Akuapem North District perceived to have derived from the Lesson Study Model. The study was a descriptive survey that used the mixed method approach. A 33-item semi-structured questionnaire rated using 5-points Likert scale, and focus group interviews were used to collect data. A combination of purposive and convenient sampling procedures was used to select 46 basic school teachers. Data obtained from questionnaire were analysed using means, standard deviation, and percentage while analysis of verbatim quotations from focus group interviews was used for triangulation. The results revealed that teachers felt their competences in the four thematic areas (knowledge in subject matter, lesson planning, lesson preparation and teaching material preparation and usage) which were the focus of the Lesson Study Model, had improved and in some areas much tremendously.

A method is described intended for distributed calibration of a probe microscope scanner consisting in a search for a net of local calibration coefficients (LCCs) in the process of automatic measurement of a standard surface, whereby each point of the movement space of the scanner can be defined by a unique set of scale factors. Feature-oriented scanning (FOS) methodology is used to implement the distributed calibration, which permits to exclude in situ the negative influence of thermal drift, creep and hysteresis on the obtained results. The sensitivity of LCCs to errors in determination of position coordinates of surface features forming the local calibration structure (LCS) is eliminated by performing multiple repeated measurements followed by building regression surfaces. There are no principle restrictions on the number of repeated LCS measurements. Possessing the calibration database enables correcting in one procedure all the spatial distortions caused by nonlinearity, nonorthogonality and spurious crosstalk couplings of the microscope scanner piezomanipulators. To provide high precision of spatial measurements in nanometer range, the calibration is carried out using natural standards – constants of crystal lattice. The method allows for automatic characterization of crystal surfaces at room temperature. The method may be used with any kind of scanning probe microscope (SPM).

A number of improvements have been added to the existing analytical model of hysteresis loops defined in parametric form. In particular, three phase shifts are included in the model, which permits us to tilt the hysteresis loop smoothly by the required angle at the split point as well as to smoothly change the curvature of the loop. As a result, the error of approximation of a hysteresis loop by the improved model does not exceed 1%, which is several times less than the error of the existing model. The improved model is capable of approximating most of the known types of rate-independent symmetrical hysteresis loops encountered in the practice of physical measurements. The model allows building smooth, piecewise-linear, hybrid, minor, mirror-reflected, inverse, reverse, double, and triple loops. One of the possible applications of the model developed is linearization of a probe microscope piezoscanner. The improved model can be found useful for the tasks of simulation of scientific instruments that contain hysteresis elements.

Scanning tunneling microscopy (STM) gives us the opportunity to map the surface of functionalized carbon nanotubes in an energy resolved manner and with atomic precision. But this potential is largely untapped, mainly due to sample stability issues which inhibit reliable measurements. Here we present a simple and straightforward solution that makes away with this difficulty, by incorporating the functionalized multiwalled carbon nanotubes (MWCNT) into a few layer graphene - nanotube composite. This enabled us to measure energy resolved tunneling conductance maps on the nanotubes, which shed light on the level of doping, charge transfer between tube and functional groups and the dependence of defect creation or functionalization on crystallographic orientation.

Scanning tunneling microscopy (STM) gives us the opportunity to map the surface of functionalized carbon nanotubes in an energy resolved manner and with atomic precision. But this potential is largely untapped, mainly due to sample stability issues which inhibit reliable measurements. Here we present a simple and straightforward solution that makes away with this difficulty, by incorporating the functionalized multiwalled carbon nanotubes (MWCNT) into a few layer graphene -nanotube composite. This enabled us to measure energy resolved tunneling conductance maps on the nanotubes, which shed light on the level of doping, charge transfer between tube and functional groups and the dependence of defect creation or functionalization on crystallographic orientation.