First experiments

Although in the papers (6), (10) organic materials were used as a model acceptor, the first experimental demonstration of the new concept of LEDs was performed by Victor Klimov s (53) group by investigating the energy transfer from a quantum well (donor) to a monolayer of semiconductor nanocrystals (acceptor) having, however, a broad absorption spectrum (as most organic materials do). The structure studied in these experiments is depicted in Fig. 13.8a. 

Schematic and optical properties of the hybrid quantum-well/nanocrystal structure, (a). The structure consists of an InGaN/GaN quantum-well heterostructure with a monolayer of TOPO/TOP-capped CdSe/ZnS core/shell nanocrystals on top of it. Electron-hole pairs in the quantum well can experience nonradiative resonant transfer into nanocrystals. The nanocrystals excited by energy transfer produce emission with a wavelength determined by the nanocrystal size. (b). The emission of the quantum well (blue) spectrally overlaps with the absorption of the nanocrystals (green). For CdSe nanocrystals with 1.9 nm radius, the emission wavelength is around 575 nm (red) (from (13)). 

An approach with indirect injection of electron-hole excitations into nanocrystals by the above described noncontact nonradiative Forster-like energy transfer from a proximal quantum well that can in principle be pumped either electrically or optically, can solve the problem of pumping of nanocrystals. The result obtained by the Klimov group indicate that this energy transfer is fast enough to compete with electron-hole recombination in the quantum well, and results in 

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The surface forces apparatus of crossed mica cylinders (Section VI-4D) has provided a unique measurement of friction on molecular scales. The apparatus is depicted in Fig. VI-3, and the first experiments involved imposing a variation or pulsing in the sepa-... 

In the first experiment, the fact that they are mutually commutative allowed us to expand the 64 % probable eigenstate with L=1 in terms of functions that were eigenfunctions of the operator for which measurement was about to be made without destroying our knowledge of the value of L. That is, because and can have simultaneous eigenfunctions, the L = 1 function can be expanded in terms of functions that are eigenfunctions of both and L. This in turn, allowed us to find experimentally the... 

Two experiments are described in this paper. In the first experiment students determine the %w/w orange oil in a prepared sample by analyzing for d-limonene using anisole as an internal standard. Separations are accomplished using... 

Compliance Audits If a new toll process causes a toller s first experience with OSHA PSM or EPA RMP compliance, this... 

Interesting developments were also taking place in the field of thermosetting resins. The melamine-formaldehyde materials appeared commercially in 1940 whilst soon afterwards in the United States the first contact resins were used. With these materials, the forerunners of today s polyester laminating resins, it was found possible to produce laminates without the need for application of external pressure. The first experiments in epoxide resins were also taking place during this period. 

The problem is made more difficult because these different dispersion processes are interactive and the extent to which one process affects the peak shape is modified by the presence of another. It follows if the processes that causes dispersion in mass overload are not random, but interactive, the normal procedures for mathematically analyzing peak dispersion can not be applied. These complex interacting effects can, however, be demonstrated experimentally, if not by rigorous theoretical treatment, and examples of mass overload were included in the work of Scott and Kucera [1]. The authors employed the same chromatographic system that they used to examine volume overload, but they employed two mobile phases of different polarity. In the first experiments, the mobile phase n-heptane was used and the sample volume was kept constant at 200 pi. The masses of naphthalene and anthracene were kept... 

In the first experiment, Gady measured the bend of the cantilever as a function of particle-to-substrate displacement. This allowed him to determine the power-... 

The first experiment with the electrostatic gas cleaning was made in 1824, when Hohlfeld show that a fog was cleared from a glass jar which contained an electrically charged point electrode. Similar demonstrations were published in the 19th century, an example being the precipitation of tobacco smoke in a glass cylinder by Guitard (1850). 

As the second major measurement, consider uniaxial tension loading in the 2-direction on a flat piece of unidirectionally reinforced lamina as in Figure 2-25. As in the first experiment, e-, and eg are measured so... 

When starting our first experiments with available ionic liquids, in screening programs to identify suitable systems, we encountered several difficulties such as pH shifts or precipitation. More generally, the following aspects should be taken into account when ionic liquids are used with biocatalysts ... 

What is going to be the first area of broad, commercial ionic liquid application This is probably the question most frequently asked of everybody who is active in developing ionic liquid methodology. The answer is not easy to give. Some petrochemical processes are ready to be licensed or are in pilot plant development (as described in Section 5.2), but there is still some time needed to bring these applications on stream and to claim a broad replacement of existing technologies by ionic liquids in this area. For some non-synthetic applications, in contrast, the lead time from the first experiments to full technical realization is much shorter. 

The first experiments with the thermal electric engine were conducted in Russia in 1929 by its inventor, Valentin P. Glushko, who later became a world-famous authority in rocket propulsion. For more than forty years, the United States and Russia have devoted many resources to research and development of various kinds of EREs. First tested in space by the Russians in 1964, these engines have found some limited applications in modern space technology. For more than two decades Russian weather and communication satellites have regularly used electric rocket engines for orbital stabilization. The first spacecraft to employ ERE for main propulsion was the American asteroid exploration probe Deep Space 1, launched in 1998. The performance of... 

Consider an unknown base, RNH. One experiment titrates a 50.0-mL aqueous solution containing 2.500 g of the base. This titration requires 59.90 mL of 0.925 M HC1 to reach the equivalence point. A second experiment uses an identical 50.0-mL sohidon of the unknown base that was used in the first experiment. To this solution is added 29.95 mL of0.925 M HCL The pH after the HC1 addition is 10.77. 

The first experiments on the plasma chemical decomposition of fluoride solutions containing tantalum or niobium to obtain tantalum and niobium oxides were reported about fifteen years ago [524]. Subsequent publications were devoted to further development and expansion of the method for other refractory rare metals such as titanium and zirconium [525 - 532]. 

Besides the necessity for improvement in efficiency, stability is another problem for all the applications of conjugated polymers. First experiences on conju-... 

While in first experiments the diastereomeric ratios were not determined, the addition of optically active /erf-butyl 2-(4-methylphenylsulfinyl)acetate to prostereogenic carbonyl compounds proceeded with high asymmetric induction34-38. 

Fig. 32. Double-jump experiments of unfolding and refolding. The peptide [(Ala-Gly-Pro)s]3 in 50 ml phosphate buffer (pH 7.5) was incubated at 9.2 °C and quickly unfolded by a first temperature jump from 9.2 to 30 °C. This process took 25 s, the time needed to reach the final temperature. In a first experiment (curve A), the second jump back from 30 to 9.2 °C followed immediately after complete unfolding of the peptide, i.e. 25 s after the first jump. In a second and a third experiment (curve B, C), the time lapse between the first and the second jump was 75 and 125 s, respectively...

Cyclic voltammetry is the most widely used technique for acquiring qualitative information about electrochemical reactions. The power of cyclic voltammetry results from its ability to rapidly provide considerable information on the thermodynamics of redox processes, on the kinetics of heterogeneous electron-transfer reactions, and on coupled chemical reactions or adsorption processes. Cyclic voltammetry is often the first experiment performed in an electroanalytical study. In particular, it offers a rapid location of redox potentials of the electroactive species, and convenient evaluation of the effect of media upon the redox process. 

It is clear from Figure 1 that in the first experiment (Figure la) f and f. were oscillated in opposition of phase with maximum possible amplitude of the pump setting. In the second experiment (Figure lb) nearly rectangular waves were used for... 

Esposito, S., Ragazzoni, R., Riccardi, A., O Sullivan, C., Ageorges, N., Red-fern, M., and Davies, R., 2000, Absolute tilt from a laser guide star a first experiment, Exp. A., 10, 135... 

Figure 10. The relationship between the initial glycogen content in vastus lateralis muscle and work time in six subjects who cycled to exhaustion at 75% VO2 max. Each subject cycled to exhaustion on three occasions. The first experiment was preceded by a mixed diet (a), the second by a carbohydrate-poor diet (o), and the third by a carbohydrate-rich diet ( ). The energy contents of the diets were identical. In all experiments depletion of the muscle glycogen store coincided with exhaustion and muscle fatigue. From Bergstrom et al. (1967) with permission from the publisher.

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