First time

His wonderful and short presentation describes for the first time ... 

The introduction of automated scanning systems was a great leap forward in the development. That way, the uncertainties of manual probe guidance were eliminated. Usually, these systems were designed for high-frequency surface tests and followed the outer profile of the surface with a probe that could be moved in several axes. A continuous 100 % scan became possible and, as a result, the documentation of the tests with stripchart recorders suggested itself. Now for the first time, wheel testing became retraceable. 

By using modern high-performance computers, it has become possible to present the test data planiform. That way, for the first time a direct relation between the test signals and the test item could be achieved. 

Physical mechanism of two-side filling of dead-end capillaries with liquids, based on liquid film flow along the wall, is proposed for the first time. Theoretical model correlates with experimental data. 

While evidence for hydration forces date back to early work on clays [1], the understanding of these solvent-induced forces was revolutionized by Horn and Israelachvili using the modem surface force apparatus. Here, for the first time, one had a direct measurement of the oscillatory forces between crossed mica cylinders immersed in a solvent, octamethylcyclotetrasiloxane (OMCTS) [67]. 

In a first time iirterval of the scheme (A3.13.46), a superposition state is prepared. This step... 

To date, researchers have identified more than 100 different molecules, composed of up to 13 atoms, in the interstellar medium [16]. Most were initially detected at microwave and (sub)millimetre frequencies, and the discoveries have reached far beyond the mere existence of molecules. Newly discovered entities such as difhise mterstellar clouds, dense (or dark) molecular clouds and giant molecular cloud complexes were characterized for the first time. Indeed, radioastronomy (which includes observations ranging from radio to submillunetre frequencies) has dramatically changed our perception of the composition of the universe. Radioastronomy has shown that most of the mass in the interstellar medium is contained in so-called dense... 

STM found one of its earliest applications as a tool for probing the atomic-level structure of semiconductors. In 1983, the 7x7 reconstructed surface of Si(l 11) was observed for the first time [17] in real space all previous observations had been carried out using diffraction methods, the 7x7 structure having, in fact, only been hypothesized. By capitalizing on the spectroscopic capabilities of the technique it was also proven [18] that STM could be used to probe the electronic structure of this surface (figure B1.19.3). 

It is interesting to note that this is the first time that in the present framework the quantization is formed by two quantum numbers a number n to be termed the principal quantum number and a number , to be termed the secondary quantum number. This case is reminiscent of the two quantum numbers that characterize the hydrogen atom. 

Abstract. This paper presents results from quantum molecular dynamics Simula tions applied to catalytic reactions, focusing on ethylene polymerization by metallocene catalysts. The entire reaction path could be monitored, showing the full molecular dynamics of the reaction. Detailed information on, e.g., the importance of the so-called agostic interaction could be obtained. Also presented are results of static simulations of the Car-Parrinello type, applied to orthorhombic crystalline polyethylene. These simulations for the first time led to a first principles value for the ultimate Young s modulus of a synthetic polymer with demonstrated basis set convergence, taking into account the full three-dimensional structure of the crystal. 

The Car-Parrinello quantum molecular dynamics technique, introduced by Car and Parrinello in 1985 [1], has been applied to a variety of problems, mainly in physics. The apparent efficiency of the technique, and the fact that it combines a description at the quantum mechanical level with explicit molecular dynamics, suggests that this technique might be ideally suited to study chemical reactions. The bond breaking and formation phenomena characteristic of chemical reactions require a quantum mechanical description, and these phenomena inherently involve molecular dynamics. In 1994 it was shown for the first time that this technique may indeed be applied efficiently to the study of, in that particular application catalytic, chemical reactions [2]. We will discuss the results from this and related studies we have performed. 

In 1814, J.J. Berzelius succeeded for the first time in systematically naming chemical substances by building on the results of quantitative analyses and on the definition of the term "element by Lavoisier. In the 19th century, the number of known chemical compounds increased so rapidly that it became essential to classify them, to avoid a complete chaos of trivial names (see Section 2.2.4). 

A further milestone was achieved in 1977 by Richardson ct ah They could for the first time visualize a complete protein structure from X-ray ciystallography data 19h. A large numlier of structures were generated in the following years. 

Bonaccorsi ct al. [204 defined for the first time the molecular electrostatic potential (MEP), wdicli is dearly tfie most important and most used property (Figure 2-125c. The clcctro.static potential helps to identify molecular regions that arc significant for the reactivity of compounds. Furthermore, the MEP is decisive for the formation of protein-ligand complexes. Detailed information is given in Ref [205]. 

The importance of all this work lies in the fact that it established for the first time that chemical reactivity data for a wide series of reactions can be put onto a quantitative footing. With continuing research, however, it was found that the various chemical systems required quite specific substituent constants of their own, leading to a decline in interest in LEER. Nevertheless, substituent constant scales are still in use and methods for calculating or correlating them are still of interest [12]. 

This comprises original publications in scientific journals or serials proceedings, in which the latest information and data are published for the first time. Primary literature includes dissertations and theses, journals, patents, conference proceedings, research reports, and preprints the latter three are often called gray literature). 

In the first time step (At), the velocities advance from time t=() to (t +1/2 At). In doing so, they Meap" over the positions at time t. The current velocities are then calculated using etiiiation 27. Th IS equation supplies on ly approximate velocities used to cal-cii late energies at time t. 

We have used a common notation from mechanics in Eq. (5-4) by denoting velocity, the first time derivative of a , x, and acceleration, the second time derivative, x. In a conservative system (one having no frictional loss), potential energy is dependent only on the location and the force on a particle = —f, hence, by differentiating Eq. (5-3),... 

Quantum mechanics is cast in a language that is not familiar to most students of chemistry who are examining the subject for the first time. Its mathematical content and how it relates to experimental measurements both require a great deal of effort to master. With these thoughts in mind, the authors have organized this introductory section in a manner that first provides the student with a brief introduction to the two primary constructs of quantum mechanics, operators and wavefunctions that obey a Schrodinger equation, then demonstrates the application of these constructs to several chemically relevant model problems, and finally returns to examine in more detail the conceptual structure of quantum mechanics. 

Even with the assuranee that quantum meehanies has firm underpinnings in experimental observations, students learning this subjeet for the first time often eneounter diffieulty. Therefore, it is useful to again examine some of the model problems for whieh the Sehrodinger equation ean be exaetly solved and to learn how the above rules apply to sueh eonerete examples. 

It is obvious that the reaction is accelerated markedly by water. However, for the first time, the Diels-Alder reaction is not fastest in water, but in 2,2,2-trifiuoroethanol (TFE). This might well be a result of the high Bronsted acidity of this solvent. Indirect evidence comes from the pH-dependence of the rate of reaction in water (Figure 2.1). Protonation of the pyridyl nitrogen obviously accelerates the reaction. 

Having available, for the first time, a reaction that is catalysed by Lewis acids in water in an enantioselective fashion, the question rises how water influences the enantioselectivity. Consequently,... 

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