Search results for " Force"
showing 10 items of 2250 documents
Phonons in MoSe2/WSe2 van der Waals heterobilayer
2021
We report first-principles calculations of the structural and vibrational properties of the synthesized two-dimensional van der Waals heterostructures formed by single-layers dichalcogenides MoSe2 and WSe2. We show that, when combining these systems in a periodic two-dimensional heterostructures, the intrinsic phonon characteristics of the free-standing constituents are to a large extent preserved but, furthermore, exhibit shear and breathing phonon modes that are not present in the individual building blocks. These peculiar modes depend strongly on the weak vdW forces and has a great contibution to the thermal properties of the layered materials. Besides these features, the departure of fl…
Usytuowanie ustrojowo-polityczne ochrony informacji niejawnych w Polsce, Czechach i na Słowacji
2022
Za system ochrony informacji niejawnych w Polsce odpowiadają służby specjalne. W Czechach i na Słowacji do prowadzenia działań w tym zakresie powołano centralne urzędy cywilne działające poza systemem służb specjalnych. Instytucje zajmujące się ochroną informacji niejawnych w polskim systemie ustrojowym i konstytucyjnym są nadzorowane głównie przez władzę wykonawczą — premiera, podczas gdy w Czechach i na Słowacji głównym czynnikiem kontrolnym w systemie są specjalne komisje parlamentarne. Ochronę praw osób, których dane są przetwarzane w ramach różnego rodzaju postępowań prowadzonych przez takie organy, gwarantują we wszystkich analizowanych systemach politycznych sądy. Na Słowacji jest to…
Crystal Structures and Density Functional Theory Calculations of o-and p-Nitroaniline Derivatives: Combined Effect of Hydrogen Bonding and aromatic i…
2013
The interplay of strong and weak hydrogen bonds, dipole–dipole interactions, and aromatic interactions of o- and p-nitroaniline derivatives was studied by combining crystal structure analysis and density functional theory (DFT) calculations. Crystal structures of four 2-nitroaniline derivatives, 2-((2-nitrophenyl)amino)ethyl methanesulfonate (1A), 2-((2-nitrophenyl)amino)ethyl 4-methylbenzenesulfonate (2A), N,N′-((1,3-phenylenebis(oxy))bis(ethane-2,1-diyl))bis(2-nitroaniline) (3A), and N-(2-chloroethyl)-2-nitroaniline (4A), and crystal structures of three 4-nitroaniline derivatives, 2-((4-nitrophenyl)amino)ethyl methanesulfonate (1B), 2-((4-nitrophenyl)amino)ethyl 4-methylbenzenesulfonate (…
Evidence of Weak Halogen Bonding: New Insights on Itraconazole and its Succinic Acid Cocrystal
2012
Exact knowledge of the crystal structure of drugs and lead compounds plays a significant role in the fields of crystal engineering, docking, computational modeling (drug–receptor interactions), and rational design of potent drugs in pharmaceutical chemistry. The succinic acid cocrystal of the systemic antifungal drug, itraconazole, reported by Remenar et al. (J. Am. Chem. Soc.2003, 125, 8456–8457) (CSD: IKEQEU), represents one of the classical examples displaying a molecular fitting mechanism in the solid state. In this work, we disclose the X-ray single-crystal structure of the cis-itraconazole–succinic acid (2:1) cocrystal and found that it differs slightly from the previously reported st…
The Crisis on the Labor Market in Romania
2007
In the last 17 years the labor market in Romania has suffered deep changes. We can found two distinct stages regarding the evolutions on the labor market in Romania after 1989. The first stage, which includes the period 1990 – 2003, is defined as a period of deep restructurations of the Romanian economy. It is characterized as a period of relatively high unemployment and the undertaken actions were directed mainly at limiting the unemployment and its harmful effects on the society. We consider that after 2005 the employment evolution heads towards a new crisis on the labor market, but its cause is not a high unemployment, but rather an offer dropping on the labor market. The causes and the …
Filipinas en el marco del imperio español en el siglo XIX
2019
[EN] En este artículo se analiza la evolución de Filipinas en las últimas décadas del siglo XVIII y en el transcurso del siglo XIX a través de diferentes epígrafes: la obligada transformación del secular modelo colonial volcado hacia el tráfico del Galeón y las relaciones transpacíficas; la renovada inclinación hacia Asia, el océano Índico y el mar de China; el desarrollo de un sistema económico basado en la exportación de productos filipinos y en la apertura de las islas al exterior; la evolución de la vida política; el camino hacia la modernización; el peso de las órdenes religiosas, la importancia de la población china y la colaboración con élites indígenas como rasgos singulares de Fili…
Synthesis, X-Ray Structure, Tautomerism Aspect, and Chemical Insight of The 3-(1H-Indol-2-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-ol
2021
The 3-(1H-indol-2-yl)-7H-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazin-6-ol 2 was obtained exclusively in the enol configuration starting from triazolyl-indole derivative 1 and alkyl halo-esters in the presence of K2CO3. Chemical structure elucidations with the aid of physicochemical characterizations were used to predict its molecular structure while single crystal X-ray diffraction technique was used to shed the light on the supramolecular structure of 2. DFT calculations agreed very well with the reported X-ray structure where the most stable form thermodynamically is the enol form. Its optimized geometry agreed very well with the experimental structure where the correlation coefficients betwe…
A different glimpse into mobilities: On the interrelations between daily spatial mobility and social mobility
2017
We explore the link between daily spatial mobility and social mobility, taking changes in the contemporary labor market and family as examples. We propose a new theoretical approach to mobility that is defined as a productive force of social labor. Analyzing the relationship between daily spatial mobility and social mobility, we show that spatial mobility has become a strategy of compensation for the lack of social mobility. Explanations for the increase in daily spatial mobility are also provided. Lastly, we reveal how spatial mobility has the capacity to produce major social change, taking the family as an example. peerReviewed
Economic Activity in Context of Regions, Education Level, Age Group and Gender: Case of Latvia
2019
In the National Development Plan of Latvia 2014–2020 it is written that society is aware that social, regional and opportunity inequalities can be reduced by a high overall employment rate in which everyone seeks for productivity. High employment rate is important not only for decreasing inequalities in country, but also for promoting economic growth. There have always been employment challenges in Latvia that are complex and insufficiently researched in academic research. The aim of the study is to analyse economic activity in Latvia by regions, education level, age group and gender. Research methods used in preparation of the article: scientific publication and previous conducted research…
Comparison of impact characteristics of different ice hockey arena dasher boards
2012
During last years the incidence and severity of ice hockey related concussions have been increased and, hence, something should be done to stop this growth. The main aim of this study was to find out how dasher board materials and structures affect impact characteristics and, thereby, the risk of concussions. The measurements were divided into two parts; in the first part, the physiological characteristics of body checks were determined in real game measurements, and the second part, consisted of simulation of body checks in the laboratory. High speed cameras and accelerometers were used to collect data. More flexible protective shielding material (dasher board B) resulted in lower peak for…