Résultats de recherche pour « Scientific Growth »

The International Particle Physics Outreach Group (IPPOG) has been making concerted and systematic efforts to present and popularise particle physics across all audiences and age groups since 1997. Today the scientific community has in IPPOG a strategic pillar in fostering long-term, sustainable support for fundamental research around the world. One of the main tools IPPOG has been offering to the scientific community, teachers and educators for almost 10 years is the Resource Database (RDB), an online platform containing a collection of high quality engaging education and outreach materials in particle physics and related sciences.

It is important for all to realize that science seldom offers the correct or ideal solution to a problem; in most cases it offers only options, and the choice of one option over another can be justified only by the preponderance of good effects over bad.

Single crystals of iridates are usually grown by a flux method well above the boiling point of the SrCl2 solvent. This leads to non-equilibrium growth conditions and dramatically shortens the lifetime of expensive Pt crucibles. Here, we report the growth of Sr2IrO4, Sr3Ir2O7 and SrIrO3 single crystals in a reproducible way by using anhydrous SrCl2 flux well below its boiling point. We show that the yield of the different phases strongly depends on the nutrient/solvent ratio for fixed soak temperature and cooling rate. Using this low-temperature growth approach generally leads to a lower temperature-independent contribution to the magnetic susceptibility than previously reported. Crystals of SrIrO3 exhibit a paramagnetic behavior that can be remarkably well fitted with a Curie-Weiss law yielding physically reasonable parameters, in contrast to previous reports. Hence, reducing the soak temperature below the solvent boiling point not only provides more stable and controllable growth conditions in contrast to previously reported growth protocols, but also extends considerably the lifetime of expensive platinum crucibles and reduces the corrosion of heating and thermoelements of standard furnaces, thereby reducing growth costs.

International Cardiovascular Research Journal has been recently indexed in PubMed. In order to evaluate the role of this journal in global and international scientific growth, the scientific growth of cardiovascular researches in the past 13 years has been evaluated. In this way, one can compare the role of this journal in Iran and Iran’s role in the global scientific growth rate. Each year, new medical inventions and discoveries all around the world have major influences on increase of public health and decrease of treatment expenditures. It is obvious that in case the results of a study have not been published, that study has not probably been done or reached any result. Therefore, in evaluation of scientific researches, one may think that only published (and indexed) articles should be taken into account. The number of officially indexed articles in acceptable databases is considered as a manifestation of progression in any field. In the field of medical sciences, PubMed is one of the main databases in which each paper is valuable. In addition, the number of indexed papers in PubMed is considered as a good criterion for determining the progresses in medical sciences. This study aims to identify the scientific outcomes in the field of cardiovascular researches both in Iran and around the world during the past 13 years. According to the statistics, more than 32000 articles were indexed in PubMed during 2000. This figure increased to more than 54000 in 2013, showing a 69% increase during 13 years. Moreover, 11 articles from or about Iran were indexed in this field during 2000, while this measure was reported to be 550 in 2013, revealing a 5000% increase in this area. A year-to-year comparison indicates that Iran’s publications growth rate in this field has always been higher than that of the world. This implies that cardiovascular sciences have a higher rate in Iran compared to the world. Figure 1 depicts the results of an annual comparison between Iran and the world. In addition, Table 1 shows the exact values of the comparisons presented in Figure 1. Figure 1. The Annual Scientific Growth Rate in Cardiovascular Researches in Iran and the World Table 1. The Annual Number of Articles in the Field of Cardiovascular Researches (1) International Cardiovascular Research Journal is a quarterly journal indexed in PubMed which publishes about 40 articles every year. Considering this journal’s broad range of authors, it has a significant role in increasing Iran’s scientific share and can play even a more significant role in this regard in future.

Controlling the growth kinetics from the vapor phase has been a powerful paradigm enabling a variety of metastable epitaxial semiconductors such as Sn-containing group IV semiconductors (Si)GeSn. In addition to its importance for emerging photonic and optoelectronic applications, this class of materials is also a rich platform to highlight the interplay between kinetics and thermodynamic driving forces during growth of strained, nonequilibrium alloys. Indeed, these alloys are inherently strained and supersaturated in Sn and thus can suffer instabilities that are still to be fully elucidated. In this vein, in this work the atomic-scale microstructure of Ge0.82Sn0.18 is investigated at the onset of phase separation as the epitaxial growth aborts. In addition to the expected accumulation of Sn on the surface leading to Sn-rich droplets and sub-surface regions with the anticipated equilibrium Sn composition of 1.0at.%, the diffusion of Sn atoms also yields conspicuous Sn-decorated filaments with nonuniform Sn content in the range of ~1 to 11at.% . The latter are attributed to the formation and propagation of dislocations, facilitating the Sn transport toward the surface through pipe diffusion. Furthermore, the interface between the Sn droplet and GeSn shows a distinct, defective layer with Sn content of ~22at.%. This layer is likely formed by the expelled excess equilibrium Ge as the Sn solidifies, and its content seems to be a consequence of strain minimization between tetragonal Sn-rich and cubic Ge-rich equilibrium phases. The elucidation of these phenomena is crucial to understand the stability of GeSn semiconductors and control their epitaxial growth at a uniform composition.

Background: The international standing of a nation is based on its status in science production. Objectives: We aimed to assess the scientific growth and global ranking of Iran regarding the domain of medical sciences, based on the Scopus database. Methods: In the scientometric evaluation, we considered two indicators for the evaluation of Iran's global ranking in medical sciences and medicine, as a subcategory of medical science namely the number of documents and citations using the Scopus database (ranking of countries was extracted from the SCImago website). Results: Iran’s trend in the number of documents and citations was progressive. This improvement trend had a slower slope in the medical sciences and emergency medicine. Conclusion: The results showed Iran's scientific growth to be consistent. It is recommended that indexing Iranian journals in the Scopus database, promoting scientific collaborations, and providing the necessary funding could promote Iran's scientific growth.

Flux growth involves dissolving the components of the target compound in an appropriate flux at high temperatures and then crystallizing under supersaturation controlled by cooling or evaporating the flux. A refractory crucible is generally used to contain the high temperature melt. The reaction between the melt and crucible materials can modify the composition of the melt, which typically results in growth failure, or contaminates the crystals. Thus one principle in designing a flux growth is to select suitable flux and crucible materials thus to avoid any reaction between them. In this paper, we review two cases of flux growth in which the reaction between flux and Al$_2$O$_3$ crucible tunes the oxygen content in the melt and helps the crystallization of desired compositions. For the case of La$_5$Pb$_3$O, Al$_2$O$_3$ crucible oxidizes La to form a passivating La$_2$O$_3$ layer which not only prevents further oxidization of La in the melt but also provides [O] to the melt. For the case of La$_{0.4}$Na$_{0.6}$Fe$_2$As$_2$, it is believed that the Al$_2$O$_3$ crucible reacts with NaAsO$_2$ and the reaction consumes oxygen in the melt thus maintaining an oxygen-free environment.

We report the results of a new method of measuring the capillary length for the dendritic crystal growth of non-faceted materials. This method uses a nearly spherical crystal held near unstable equilibrium in an oscillating temperature field. For the growth of ammonium chloride crystals from aqueous solution, previous published estimates of the capillary length varied by over a factor of 20. With this new method, we find the product of the diffusion constant and capillary length $D d_0$ to be $0.78 \pm 0.07 \,\mathrm{μm^3/s}$, similar to that obtained for ammonium bromide crystals.

Introduction: Complex Regional Pain Syndrome (CRPS) is a pathological entity that carries a high burden of disease and reduces disability-free life expectancy and quality of life. Previously, the research patterns and general characteristics of the scientific production on CRPS have not been evaluated or analyzed. Methods: Cross-sectional bibliometric study that used Scopus as the data source. Results: 3081 documents were selected, published between 1969 and 2024. 69% (n=2126) of the articles corresponded to original articles, followed by 13.2% (n=406); it was observed an international collaboration accounted for 11.49% and an annual scientific growth accounted for 7.63%. The most frequently used terms in CRPS research are causalgia, rehabilitation, allodynia, treatment, and inflammation. Reflex sympathetic dystrophy, causalgia, and spinal cord stimulation are the most popular topics to date. As an emerging central theme, there is increasing research on cortical reorganization. The construction of the thematic map revealed that niches of topics include depression and quality of life, as well as autoimmunity. Conclusions: This study revealed a significant increase in global research and scientific publications on CRPS, with the United States being the most prolific country and achieving the greatest impact. However, it is Dutch institutions that have made the most substantial contributions to this research field. Among the most common research patterns, it is found that causalgia, rehabilitation, allodynia, treatment, and inflammation are the most frequently used keywords, while reflex sympathetic dystrophy, causalgia, and spinal cord stimulation are the most addressed topics to date.