Ternäre Chloride in den Systemen ACl/EuCl3(A = Na?Cs)

Double Chlorides in the Systems ACl/EuCl₃ (A = Na? Cs) The phase diagrams of the pseudobinary systems ACl/EuCl₃ (A = Na? Cs) were investigated by DTA. T? and H? A₃EuCl₆ with A = Cs, Rb and T? and H? NaEuCl₄ were found in addition to other compounds already described in literature. Their powder diffractograms were indexed in analogy to known structure families. By solution calorimetry and measurements of e.m.f. = f(T) in galvanic cells for solid electrolytes the enthalpies ΔH and free enthalpies ΔG for the formation of the ternary chlorides from the compounds adjacent in the systems were determined. With KCl and NaCl only the compounds A₂EuCl₅ and NaEuCl₄ are stable at ambient temperature. Compared to the system with LnCl₃ (Ln = La? Nd) investigated previously, a tendency to structures with lower coordination numbers exists as was already detected in the systems ACl/SmCl₃.     

Efficient cross-coupling of secondary alkyltrifluoroborates with aryl chlorides--reaction discovery using parallel microscale experimentation

Microscale parallel experimentation was used to discover three catalyst systems capable of coupling secondary organotrifluoroborates with sterically and electronically demanding aryl chlorides and bromides. The ensuing results represent the first comprehensive study of alkylboron coupling to aryl chlorides and, in particular, using secondary alkylboron partners. A ligand-dependent beta-hydride elimination/reinsertion mechanism was implicated in the cross-coupling of more hindered substrates, leading to isomeric mixtures of coupled products in some cases.     

Diagrammatic structure of the general coupled cluster equations

The general formula for the number of diagrammatic terms occurring in the T_n equation within a particular coupled cluster model is derived. Both the antisymmetrized and Goldstone diagrams are considered. In addition to the full coupled cluster equation approximate approaches are discussed, and for each the general formula for the number of terms is given. Analogous expressions are presented for the number of diagrammatic terms contributing to the elements of the transformed Hamiltonian [Hbar] = e^?T He^T .     

Nearest Object Priority Based Integrated Rough Surface Scattering Algorithm for 3D Indoor Propagation Prediction

Since rough surface scattering has a great impact on the accuracy of the propagation prediction algorithm, an integrated algorithm for indoor propagation prediction including rough surface scattering is proposed here. This algorithm is composed of a three dimensional （3D） ray tracing algorithm based on binary space partitioning （BSP） and a diffuse scattering algorithm based on Oren-Nayar＇s theory. Lack of accuracy and prohibitive time consumption are the main drawbacks of the existing ray tracing based propagation prediction models. To defy these shortcomings, the balanced BSP tree is used in the proposed algorithm to accelerate the ray tracing, while the nearest object priority technique （NOP） and in contact surface （ICS） is used to eliminate the repeated rayobject intersection tests. Therefore, the final criteria of this study are the time consumption as well as accuracy by predicting the field strength and the number of received signals. Using the proposed approaches, our algorithm becomes faster and more accurate than the existing algorithms. A detailed comparative study with existing algorithms shows that the proposed algorithm has at most 37.83% higher accuracy and 34.44% lower time consumption. Moreover, effects of NOP and ICS techniques and scattering factor on timeand ray prediction accuracy are also presented.     

Plane Sources of Waves in the Presence of Magnetic Field

In this paper the generation of harmonic waves in an elastic magneticmaterial, which is a perfect conductor of electricity, isconsidered. It has been assumed that an infinite body is subjected tothe action of an initially constant magnetic fieldH = (H,0,0) and in the plane ax+by=0 acts a source ofdistortion. It has been shown that this source may produce bothtransverse and longitudinal waves and each of them consists of two parts,which propagate with different speeds. The amplitudes and speeds in dependence on theangle between the direction of wave propagation and the magnetic fieldintensity H have been discussed.     

Aminomethylations via cross-coupling of potassium organotrifluoroborates with aryl bromides

[reaction: see text] The Suzuki-Miyaura cross-coupling reaction of N,N-dialkylaminomethyltrifluoroborates with aryl halides allows the construction of an aminomethyl aryl linkage through a disconnection based on dissonant reactivity patterns. A variety of these aminomethyltrifluoroborate substrates were prepared in good to excellent yields and then shown to cross-couple with equal facility to both electron-rich and electron-poor aryl halides as well as to a variety of heteroaromatic bromides.     

Reinvestigation of aminomethyltrifluoroborates and their application in Suzuki-Miyaura cross-coupling reactions

A reinvestigation into the chemical composition of potassium aminomethyltrifluoroborates is reported. These trifluoroborato salts have been reassigned as zwitterionic ammoniomethyltrifluoroborates. Minor adjustments to the previously disclosed reaction conditions are reported that permit a similar level of activity as nucleophiles in Suzuki-Miyaura cross-coupling reactions.     

Pulsed laser action of Pr:GdLiF4 at room temperature

We realized, to our knowledge for the first time, laser emission in Pr:GdLiF₄ at seven wavelengths: 522 nm, 545 nm, 604.5 nm, 607 nm, 639 nm, 697 nm, and 720 nm. The crystal was pumped with an excimer laser pumped dye laser at 468 nm. All laser experiments were carried out at room temperature. We also achieved pulsed room temperature laser oscillation of Pr:KYF₄ at 642.5 nm pumped at 465 nm wavelength.     

Accelerated thermal decomposition of AlH3 for hydrogen-fueled vehicles

The potential for using aluminum hydride, AlH₃, for vehicular hydrogen storage is explored. It is shown that particle-size control and doping of AlH₃ with small levels of alkali-metal hydrides (e.g. LiH) results in accelerated desorption rates. For AlH₃–20 mol% LiH, 100 °C desorption kinetics are nearly high enough to supply vehicles. It is highly likely that 2010 gravimetric and volumetric vehicular system targets (6 wt% H₂ and 0.045 kg/L) can be met with onboard AlH₃. However, a new, low-cost method of off-board regeneration of spent Al back to AlH₃ is needed. PACS 68.43.Vx; 68.43.Mn; 83.80.Fg; 84.60.Ve; 51.30.+i; 61.10.Nz