Top PDF The local adsorption geometry of benzenethiolate on Cu(1 0 0)

The local adsorption geometry of benzenethiolate on Cu(1 0 0)

The local adsorption geometry of benzenethiolate on Cu(1 0 0)

There has been considerable interest for many years in the self-assembled monolayers (SAMs) formed on noble metal surfaces by organic thiolate (RS-) molecular species created at the surface by S-H deprotonation of the thiol (RSH) or S-S bond scission of the disulfide (RS-SR). Much of this work, notably on gold surfaces, is based on deposition of the thiolates from solution, although there is also a body of work based on deposition from the gas phase under ultra-high vacuum (UHV) conditions. The resulting thiolate SAMs have actual and potential technological applications in chemical and biochemical sensing, wetting, lubrication, corrosion inhibition and molecular electronics [1, 2, 3, 4]. Despite the many experimental and theoretical investigations [1], there have been very few quantitative structural studies of the thiolate-metal interface that is a key element in gaining a detailed understanding of the adsorption and self-assembly mechanisms. In particular, the ordering of the thiolates on the surface is determined by the balance of site- specificity in the adsorption and the intermolecular interactions within the layer. The simplest model systems are the alkylthiolates (CH 3 (CH 2 ) n S-), and these have been the
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Quantitative determination of the local structure of thymine on Cu(1 1 0) using scanned energy mode photoelectron diffraction

Quantitative determination of the local structure of thymine on Cu(1 1 0) using scanned energy mode photoelectron diffraction

adsorption site of the molecule, starting with the location of the N(3) atom that lies between the two C=O carbonyls, that are also thought to be involved in the substrate bonding. In the presence of strong substrate backscattering, intramolecular scattering is usually relatively unimportant, so initially calculations were performed simply for an isolated N atom adsorbed in each of the four relatively high symmetry adsorption sites, namely atop, hollow, long bridge and short bridge. For each of these sites the height of the N emitter above the outermost surface layer was adjusted to obtain the lowest R- factor, and some optimisation of the vibrational amplitudes was undertaken for each of the best-fit structures, but no further structural optimisation (e.g. including the effects of substrate relaxation or intramolecular scattering) was undertaken at this stage. The results of these calculations were lowest R-factor values for each site of 0.32 (atop), 0.44 (hollow), 0.60 (long bridge) and 0.73 (short bridge). The last two of these can clearly be rejected. For the atop site the optimised N-Cu distance was found to be 1.96 Å, while for the hollow site the N was found to be 1.96 Å above a second layer Cu atom. In effect, therefore, both of these solutions correspond to the N atom occupying an atop site (at the same distance), the difference being whether the N lies atop outermost or second layer Cu atoms. From the structural point of view, of course, this distinction is important, but as the dominant backscattering atoms are in similar positions, the PhD data to be expected from the two sites is similar. In fact further optimisation of the atop and hollow sites, including the effect of correlated vibrations (allowing the near-neighbour scatters to have smaller vibrational amplitudes relative to the emitter) led to a significant improvement in the R-factor for the atop site to 0.25, but an even larger reduction for the hollow site to 0.26, attributable to the reduced influence of the outermost near-neighbour scatterers in the outermost layer for the hollow site, relative to that of the nearest-neighbour Cu atom below. We conclude, therefore, that the N atoms clearly does lie atop a Cu surface atom, but cannot, on this basis alone, distinguish the atop and hollow sites, as the R-factor values are too similar.
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The local structure of OH species on the V2O3(0 0 0 1) surface: a scanned energy mode photoelectron diffraction study

The local structure of OH species on the V2O3(0 0 0 1) surface: a scanned energy mode photoelectron diffraction study

PhD structural studies require the measurement of the photoemission intensity from a core level in specific directions as a function of the photoelectron energy. Modulations in the resulting spectrum arise from the change in phase of directly emitted and scattered components of the photoelectron wavefield as the photoelectron wavelength changes, and can be interpreted in terms of the scattering path lengths and thus the local geometry. In the present case the PhD modulation spectra were obtained by recording a sequence of photoelectron energy distribution curves (EDCs) around the O 1s at 4 eV steps in photon energy, in the photoelectron kinetic energy range of approximately 70-320 eV, for each of a number of different emission directions in the polar emission angle range from 0 (normal emission) to 60 in the two principle azimuthal planes, [2110] and [1010] (see Fig. 1b). Each of these data sets was processed following our general PhD methodology (see e.g. [2, 3]) in which the individual EDCs are fitted by the sum of Gaussian peaks (corresponding to the different chemically-shifted O 1s components), associated steps and a template background extracted from the high kinetic energy tails of the individual EDCs.
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Semi parabolic bifurcations in complex dimension two

Semi parabolic bifurcations in complex dimension two

Proof. By a change of variables, we may assume that the fixed points are ( ± i✏, 0). Each fixed point will have eigenvalues 1 + O(✏) and b + O(✏). There will be local strong stable manifolds corresponding to the eigenvalue b + O(✏). We apply the graph transform as in [HPS, § 5A] in order to obtain a domain for the stable manifold which is uniformly large in ✏. Rescaling coordinates, we may assume that we have graphs

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Evidence for B-0 ->pi(0)pi(0)

Evidence for B-0 ->pi(0)pi(0)

The Belle detector is a large-solid-angle spectrometer consisting of a three-layer silicon vertex detector, a 50- layer central drift chamber, an array of threshold Cherenkov counters with silica aerogel radiators, time- of-flight scintillation counters, and an electromagnetic calorimeter comprised of CsI(Tl) crystals located inside a superconducting solenoid coil that provides a 1.5 T magnetic field. An iron flux return located outside of the coil is instrumented to detect K 0

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Improvement in Mechanical Properties of a Cu 2 0 mass%Ni 0 5 mass%Si 0 1 mass%Zr Alloy by Combining Both Accumulative Roll Bonding and Cryo Rolling with Aging

Improvement in Mechanical Properties of a Cu 2 0 mass%Ni 0 5 mass%Si 0 1 mass%Zr Alloy by Combining Both Accumulative Roll Bonding and Cryo Rolling with Aging

observed the early stages of local recrystallization in ARB- processed pure Cu at room temperature. They suggested that grain size saturation during SPD is related to the combination of grain refinement advanced by the grain subdivision mechanism 24) and grain coarsening due to recrystallization. No recrystallization was directly observed by TEM in either ARB or P-ARB. Grain boundaries are locally straight in P- ARB (Fig. 3(b)), whereas they exhibit local unevenness in ARB, as indicated by the arrows in Fig. 3(a). This suggests that boundary migration (i.e., recovery and recrystallization) occurs during ARB after solutionizing and that the fi ne precipitates formed by pre-aging suppress boundary migra- tion during ARB. This is consistent with the fact that ARB has a lower dislocation density than P-ARB (Table 2). It may explain why P-ARB has a smaller grain size than ARB.
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Hackers 1 0 pdf

Hackers 1 0 pdf

También emplean de forma habitual programas sniffers para controlar la Red, interceptan tu contraseña y correo electrónico y después te envían varios mensajes, con dirección falsa amenaz[r]

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1773 0 1 pdf

1773 0 1 pdf

A common denial of service attack, known as SYN Flooding, is a method that essentially overwhelms a network interface by starting to establish a legitimate session, but never completes the handshake (or initiation protocol). Essentially, the network continues to hold open processes waiting for a complete handshake until it is eventually overwhelmed and truly legitimate users are unable to access the flooded network interface. There is no perfect solution to this type of attack. Our defense works by setting a maximum rate at which incoming connections can be established. After this connection rate is reached, the rest of the received SYN traffic is dropped. After the rate has settled down, SYN connections are allowed again. In this case study we have limited the connection set-up rate to three per second. Once that rate is achieved, additional connections are accepted at a rate of 1 per second (dropping all others, legitimate or otherwise) until the rate has decreased to below 3 per second. This may seem low, but in our case, this machine was not going to have a great deal of connections coming in from the outside world at any one given time during its legitimate usage. This defense is useful for the small organization, but is not practical for an internet-based business, as they need to respond to a wide variety of SYN traffic. You can of course raise the continuous and burst rates to suit your needs and desired traffic flows, but this is outside the scope of this project.
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Molecular Dynamics Simulation of Adsorption Behavior of Schiff base Gemini Surfactants on Zn (1 1 0) Surface

Molecular Dynamics Simulation of Adsorption Behavior of Schiff base Gemini Surfactants on Zn (1 1 0) Surface

Recent studies have indicated that Gemini surfactants can be used as corrosion inhibitor. D. Gelman and co-workers studied the correlation between Al corrosion rates and the concentrations of both PEG di-acid and ZnO in alkaline solution [4]. A. A. Mohamad and co-workers studied poly(vinyl alcohol) alkaline solid polymer in KOH solution, the results showed that the corrosion inhibitor can significantly reduce the corrosion of zinc electrode [5]. H. Yang and co-workers suppressed surface passivation of zinc anode in dilute alkaline solution using surfactant additives, which increased the discharge capacity of zinc battery [6]. W.L. Chang and co-workers studied the behavior of zinc anodes in presence of inhibitors, the results revealed that these inhibitors can improve the over- potential of hydrogen evolution and decrease the formation of zinc dendrite [7]. H.M.A. El-Lateef and co-workers studied the effect of inhibitors on carbon steel, such as CHOGS-8, CHOGS-12 and CHOGS-16 in 15% HCl solution, the results showed that the prepared surfactants were effectively inhibited the carbon steel corrosion [8]. The research on interaction between a family of Gemini amphiphilic pseudopeptides and model monomolecular film membranes [9] had aided in elucidating the role of surfactant structure in the CNT dispersion process, and reported the results of fully atomistic molecular dynamics (MD) simulations of the adsorption and surface self-assembly of Gemini surfactants [10].
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Electrochemical hydrogen storage characteristics of Mg2 xCxNi (x= 0, 
		0 1, 0 2, 0 5) alloys prepared by mechanical alloying

Electrochemical hydrogen storage characteristics of Mg2 xCxNi (x= 0, 0 1, 0 2, 0 5) alloys prepared by mechanical alloying

intermetallic were markedly enhanced by nano- crystallization and amorphization [3]; this can be kinetically improved using elemental additives substituting either Mg [4] or Ni [5] lattice sites. Noticeable improvement in the discharge capacity of the Mg-based alloys can be obtained if these alloys are synthesized by the mechanical alloying (MA). The grain size of the alloys is reduced down to 50 nm by MA and the discharge capacity can be improved up to 200 mAh g-1 at room temperature [6]. Even this improved value, however, is
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Precipitation Processes in a Cu–0 9 mass% Be Single Crystal

Precipitation Processes in a Cu–0 9 mass% Be Single Crystal

A Cu–0.9 mass% Be alloy was prepared from Cu (purity, 99.99%) and a Cu–3.81 mass% Be mother alloy. Sheet- shaped single crystals, 2 mm thick, of the alloy were grown in a graphite crucible by the Bridgman method using a seed crystal. The surface of the single crystals was parallel to the (110) plane. Specimens with compressive axis along [001] were spark cut from the single crystal. The specimens had a cross-section of 2 mm 4 mm and a length of 5 mm. All the specimens were solution treated at 820 C for 2 h, quenched

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Microstructure Control in Sn  0 7 mass%Cu Alloys

Microstructure Control in Sn 0 7 mass%Cu Alloys

quenching, while the darker areas were liquid at the time of quenching. These images clearly demonstrate that the solid- ification front advances from the edges of the sample towards the centre in the alloy with 0 ppm Ni. The solidification front is not compact and flat, but contains a semi-solid or mushy zone with the fraction of liquid increasing towards the centre of the sample. In the samples quenched at 120 and 220 s it is seen that there are a few large Sn dendrites which grow preferentially from the base of the sample. These are believed to be dendrites which were favourably orientated for growth when the base of the cup first hit the quenching liquid. The
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Hardening Behavior in Aged Al 4%Cu 0 3%Mg Alloys with 0 5 and 2%Ag Additions

Hardening Behavior in Aged Al 4%Cu 0 3%Mg Alloys with 0 5 and 2%Ag Additions

Al-Cu-Mg alloys, such as 2124, 2219 or 2618 are currently used for applications where good specific strength and heat resistant capability up to 423 K are required. 5) Typical applications are structural components in supersonics aircraft and automobiles. 5) The additions of small amounts of other elements to these alloys modify the precipitation kinetic and improve its performance at high temperatures ( 473 K). 6)

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Thermoelectric and Magnetic Properties of Pr1−xSrxMnO3 (0 1 ≦ x ≦ 0 7)

Thermoelectric and Magnetic Properties of Pr1−xSrxMnO3 (0 1 ≦ x ≦ 0 7)

layers and the C-type AFM insulating ground state for x > 0.6 with polaronic conductivity along the one-dimen- sional (1D) FM coupling, i.e., MnO chains. 26­28) Further- more, above room temperature, the crystal structure changes from orthorhombic Pbnm phases with x ¼ 0.4 to orthorhom- bic Ibmm phases with 0.4 < x < 0.5 and tetragonal I4 / mcm phases with x ½ 0.5. 26­28) Our results are consistent with prior studies, 26­28) as shown in Fig. 1 and Table 1.

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Cu(0) RDRP of styrene : balancing initiator efficiency and dispersity

Cu(0) RDRP of styrene : balancing initiator efficiency and dispersity

In the reported universal procedure and upon targeting a degree of polymerisation of 50, methyl- α -bromophenylacetate (MBPA) was used as the initiator, N,N,N ′ ,N ″ ,N ″ -pentamethyldi- ethylenetriamine (PMDETA) as the ligand and isopropanol (IPA) as the solvent while the ideal temperature was illustrated to be 60 °C. 52 Interestingly, at lower temperatures (25 – 50 °C) much slower polymerisation rates 36 hours of reaction time (Table 1, entries 1.1 – 1.6 and Fig. 3 & S2 † ). However, upon increasing the temperature to 60 °C, very high conversions could be obtained (∼ 98%) without compromising the control over the molecular weight distributions ( Đ ∼ 1.15) (Table 1, entries 1.7 – 1.8 and Fig. 3 & S3 † ). When further increasing the temperature to 70 °C a gradual broadening of the molecular weight distribution was evident ( Đ ∼ 1.25) with the final disper- sity greater than 1.4 when 80 °C was employed (Table 1, entries 1.9–1.12 and Fig. 3 & S4†). This is rather surprising as traditional ATRP of styrene typically operates well at higher temperatures and as such the higher dispersities could be attributed to the low boiling point of IPA. 53,54
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Comparative study of efficacy and safety of topical cyclosporine 0 1% and tacrolimus ointment 0 1% therapy with fluorometholone 0 1% for vernal keratoconjunctivitis

Comparative study of efficacy and safety of topical cyclosporine 0 1% and tacrolimus ointment 0 1% therapy with fluorometholone 0 1% for vernal keratoconjunctivitis

Vernal keratoconjunctivitis (VKC) is a bilateral chronic and severe inflammation of the ocular surface; underestimation and illtreatment could end up in sight threatening lesions (1) . VKC is a seasonally exacerbated entity presented in both acute and chronic form showing variation in racial, geographical and gender distribution. VKC usually begins in first decade of life and resolves after puberty but chronic severe cases could end up with permanently impaired visual acuity.VKC is usually associated with male predominance in hot arid environment (Addis, 2008; De Smedt, 2013; Bonini, 2000; Leonardi, 2006; Leonardi, 2015). Chronic Patients with moderate to severe disease usually need topical steroids for longer durations leading tosteroid induced complications as posterior subcapsular cataract, increased IOP, corneal changes, and superimposed infections in long run (Sacchetti, 2010). We analyzed the efficacy and safety of topical cyclosporine and tacrolimus in comparison to fluorometholone in treatment of moderate to severe vernal keratoconjunctivitis (VKC) which included 60 patients attending outpatient department presenting with moderate to severe VKC.
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Effect of Cu2+ Doping on Structural and Optical Properties of Synthetic Zn0 5CuxMg0 5 xFe2O4 (x = 0 0, 0 1, 0 2, 0 3, 0 4) Nano Ferrites

Effect of Cu2+ Doping on Structural and Optical Properties of Synthetic Zn0 5CuxMg0 5 xFe2O4 (x = 0 0, 0 1, 0 2, 0 3, 0 4) Nano Ferrites

ing the XRD patterns are well indexed using MDI jade 5 and full proof. The crystal structure is found to be cubic with space group Fd3m.The fined peaks are indexed as the following (220), (311), (400), and (511). The crystallite size, the lattice constant, volume, space group and density are listed in Table 1, and the crystal size is calculated using Scherer’s equation [17] [18].

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Microstructure and Properties of Rapidly Solidified Cu 0 81Cr 0 12Zr Alloy

Microstructure and Properties of Rapidly Solidified Cu 0 81Cr 0 12Zr Alloy

Different from microhardness, electrical conductivity does not decrease after the initial rapid rise. Raising the aging temperature can make more of the supersaturated solute atoms precipitate from the Cu matrix within a certain time, and therefore results in a larger conductivity. For example, aging the ribbon at 773 K for 30 min affords a conductivity of 79% IACS, while aging at 823 K for 30 min increases the conductivity to 80% IACS. Although overaging occurs as the aging temperature exceeds 773 K, the growth of the precipitates does little harm to the electrical conductivity of the alloy.
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