Narrow Results

The kinetics of irreversible dimer–dimer reaction of the type A₂+B₂→2AB has already been studied through Monte Carlo simulation via a model based on Langmuir–Hinshelwood (thermal) mechanism. The results of this study are well known. There is single transition point (y_C) at y_B=0.5 (where y_B is partial pressure of B₂ dimer in gas phase), which separates the two poisoned states from each other. Here, we have studied this reaction on the basis of a nonthermal model, which involves the precursor motion of B₂ molecule. The most interesting feature of this model is that it yields a steady reactive window. The phase diagram is similar to the ZGB model. The reactive window is separated by continuous and discontinuous irreversible phase transitions. The width of the reactive window depends upon the mobility of the precursors. The dependence of production rate on partial pressure of B₂ is shown by simple mathematical equations in our model. Some interesting results are observed when reaction between precursors and chemisorbed B atoms is considered.

In this short note, we discuss recent attempts to describe pre-crash market dynamics with analogies from the theory of critical phenomena.

One of the key factors of space weather is solar flare activity, the monitoring and prediction of which is an important task of specialized dedicated groups of space experts and solar astronomers. Solar flare forecasts are based on identifying and detecting the so-called precursors, specific processes in solar activity events that occur before flares. Collecting data for space weather analysis and prediction comes down to several types of measurements performed by more than a dozen spacecraft. Ground-based observations and monitoring nowadays are becoming more or less complimentary. One of the reasons for this is the limitation of observation time with ground-based telescopes due to adverse Earth weather conditions. However, solar radio astronomy is immune to almost any weather activity, and the main question here is what new quality it can bring. Observational data accumulated in the 20th century show that solar radio bursts can be associated with flare activity. In addition, the existing network of solar radio telescopes is already well established. As an example, in this paper, we describe the possibilities of a fully steerable 32-meter radio telescope of Ventspils International Radio Astronomy Centre (VIRAC), Latvia, which can be useful for searching for new precursors of solar flares.

The effects of boron content in camphoric carbon (CC) and graphite target of pulsed laser deposition (PLD) prepared in vacuum at room temperature on the properties of boron doped amorphous carbon (a-C:B) thin films has been studied. Deposited a-C:B films have been investigated using standard measurement techniques and the effects of B weight percentages (Bwt%) in the target are discussed. The variation of surface morphology, bonding and structural properties, as well as the optical gap (E_g) and electrical resistivity (ρ) of a-C:B films deposited using a CC target are related to the successful doping of B for low B content in the amorphous carbon (a-C) films as the structure and E_g remain almost unchanged, and the ρ decreased for the film deposited using graphite target with B powder up to 10 Bwt%. Since both E_g and ρ decreased sharply with higher Bwt%, this phenomenon may be due to graphitization. For a-C:B films deposited using graphite target with low B content at 1 and 3 Bwt%, as the E_g is observed to increase only slightly when compared with undoped a-C films and with the decrease of ρ, we speculated that the B incorporation induced successful of doping is responsible for the decrease in ρ.

Typically, Bi-Sr-Ca-Cu-O superconductors have a peculiar crystal platelet morphology caused by preferred orientations during crystal growth. Aligned platelets can be formed by reaction between Pb-Bi-O and a ceramic precursor, such as SrCaCu₂O_4+y. The alignment is due to gravitational pull on the liquid phase during sintering. The processing, microstructure and superconducting transport properties of these aligned BSCCO materials have been characterized. Scanning electron microscopy shows that thick, fiber-textured, films grow in single domains. Zero resistivity at 100 K was observed in a textured specimen sintered for 100 hours. With differential thermal analysis, the flux action of lead, which accelerates the kinetics of Bi₂Sr₂Ca₂Cu₃O_10+y formation, is understood.

We present a novel approach for separating Indic scripts with ‘matra’, which is used as a precursor to advance and/or ease subsequent handwritten script identification in multi-script documents. In our study, among state-of-the-art features and classifiers, an optimized fractal geometry analysis and random forest are found to be the best performer to distinguish scripts with ‘matra’ from their counterparts. For validation, a total of 1204 document images are used, where two different scripts with ‘matra’: Bangla and Devanagari are considered as positive samples and the other two different scripts: Roman and Urdu are considered as negative samples. With this precursor, an overall script identification performance can be advanced by more than 5.13% in accuracy and 1.17 times faster in processing time as compared to conventional system.

During the last decades, the bottom–up strategy of on-surface molecular reactions has been extensively investigated in order to fulfill controllable fabrication of covalent interlinking nanostructures/nanomaterials at atomic scale. A variety of organic reactions have been introduced to substrates, such as Ullmann coupling, Glaser coupling, cyclodehydrogenation and so on. In this paper, these on-surface molecular reactions will be reviewed from three aspects: the precursor, surface and external stimuli. Finally, a summary of past achievements and an outlook of future scientific challenges will be discussed.

Metallic colloids are frequently used in industry and provide understanding of science at microns to nanometers scales along with their applicability for various technologically important applications. Present investigations deal with morphology and structure of gold, silver and their binary composition while processing certain amounts of their solutions in a newly designed process and tapping opportunities of developing tiny-shaped particles. At tuned ratio of pulse OFF to ON time and when gold solution was processed, several tiny-shaped particles developed at the solution’s surface. Such tiny particles exert force at the tip of each converting their structure of smooth element where steady-state immersing behavior directed them toward a common centre resulting into bind them for developing different geometric anisotropic shaped particles. Under identical parameters along with pulse time, processing solutions of silver nitrate and binary composition of chloroauric acid-silver nitrate result in the development of tiny particles having no specific shape where their assembling is under the mixed behavior of forces resulting in distorted particles. Elongation and deformation of gold and silver atoms while developing different structures are because of the plastically driven behavior of their electrons. In three-dimensional structures where atoms do not undergo transition to elongate, they retain the structure as it is, which is known as hcp structure or two-dimensional structure. Different nature of precursors along with morphology and structure of particles are discussed in this paper opening abundant avenues for research.

Ni-rich Li(Ni${}_{0.8}$Co${}_{0.1}$Mn${}_{0.1})$O₂ cathode material is widely recognized as one of the most cathode materials for lithium-ion batteries due to its high specific capacity, high energy density and low cost. In this paper, the NCM cathode material precursor Ni${}_{0.8}$Co${}_{0.1}$Mn${}_{0.1}$(OH)₂ was prepared by coprecipitation method and the optimum experimental conditions were investigated. The effects of water bath temperature on the electrochemical performances of the prepared materials were investigated by controlling the morphology. The results showed that 60^∘C was the best bath temperature for the precursor which has a regular spheroidal morphology and uniform particles with the diameter of 10$\mu$m. After coprecipitation, the samples calcined under oxygen atmosphere displayed good electrochemical properties. The discharge specific capacity is up to 194mA$\cdot$h$\cdot$g${}^{-1}$ and 134mA$\cdot$h$\cdot$g${}^{-1}$ at 0.2^∘C and 5^∘C, respectively. The initial coulombic efficiency is 87.57% at 0.2^∘C.

Various low temperature treatments of Ni${}_{50.6}$Ti${}_{49.4}$ have shown an unexpected effect on the martensitic start temperature. Periodic diffuse intensity distributions in reciprocal space indicate the formation of short pure Ni strings along the $〈$111$〉$ directions in the B2 ordered lattice, precursing the formation of Ni₄Ti₃ precipitates formed at higher annealing temperatures.

We have demonstrated that variation of the precursor concentration during hydrothermal synthesis of carbon nanodots is an efficient mean to tune the yield of the products keeping their optical properties the same. Moreover, we found that the nature of the precursor determined the sensitivity and selectivity of detection of metal ions in the solution via quenching the fluorescence.

During the last decades, the bottom–fup strategy of on-surface molecular reactions has been extensively investigated in order to fulfill controllable fabrication of covalent interlinking nanostructures/nanomaterials at atomic scale. A variety of organic reactions have been introduced to substrates, such as Ullmann coupling, Glaser coupling, cyclodehydrogenation and so on. In this paper, these on-surface molecular reactions will be reviewed from three aspects: the precursor, surface and external stimuli. Finally, a summary of past achievements and an outlook of future scientific challenges will be discussed.

The electron beam induced deposition (EBID) originated contamination writing as early as 1934, and many studies have been carried out using scanning electron microscopes for various gases and conditions, and the technique was found to be very successful for a number of applications making variously shaped nano-structures. Therefore, EBID is recognized as a very promising nanofabrication technique and the amount of work devoted to this field is rapidly increasing. In this chapter, fundamentals and an overview of EBID are given in [Section Number of FUNDAMENTALS]. Recent progress is discussed in [Section Number of RECENT RESEARCH ACTIVITIES] which includes consideration of resolution improvement using 200 kV scanning transmission electron microscopy, the Monte Carlo-based calculation of a deposit shape, nanowiring and electron conductivities, three-dimensional structure fabrication, magnetic material deposition, and further trials to improve the range of material choices and the fabrication speed.