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21.
I. Weidl D. Evers P. Konrad K. E. G. Löbner U. Quade K. Rudolph S. J. Skorka 《Zeitschrift für Physik A Hadrons and Nuclei》1984,319(1):67-80
Selectively excited high-spin states in27Al have been located by the reaction12C(16O,p)27Al. The excitation functions of these states have been measured at incident energiesE cm=18.7 to 30.1 MeV at intervals of 150 keV. They exhibit maxima of presumably non-statistical origin. At four different energies the subsequent decay of the27Al states has been studied by detecting the final heavy recoils with the Munich recoil spectrometer in coincidence with the proton emitted in the first stage of the reaction. Using this new method branching ratios of theγ-, α-, andn-decay have been measured. Based on angular correlation arguments spins up to 27/2? have been determined within the experimental accuracy of 1–2?. The observations suggest a superdeformed shape of27Al at least in some of the states. 相似文献
22.
Konrad Schmüdgen 《Journal of Geometry and Physics》1999,31(4):963-264
Let (Γ, d) be the 3D-calculus or the 4D±-calculus on the quantum group SUq (2). We describe all pairs (π, F) of a *-representation π of
(SUq(2)) and of a symmetric operator F on the representation space satisfying a technical condition concerning its domain such that there exist a homomorphism of first order differential calculi which maps dx into the commutator [iF, π(x)] for x ε
(SUq (2)). As an application commutator representations of the two-dimensional left-covariant calculus on Podles quantum 2-sphere Sqc2 with c = 0 are given. 相似文献
23.
Under the assumptions thatq is not a root of unity and that the differentialsdu
j
i
of the matrix entries span the left module of first order forms, we classify bicovariant differential calculi on quantum groupsA
n–1
,B
n
,C
n
andD
n
. We prove that apart one dimensional differential calculi and from finitely many values ofq, there are precisely2n such calculi on the quantum groupA
n–1
=SL
q
(n) forn3. All these calculi have the dimensionn
2. For the quantum groupsB
n
,C
n
andD
n
we show that except for finitely manyq there exist precisely twoN
2-dimensional bicovariant calculi forN3, whereN=2n+1 forB
n
andN=2n forC
n
,D
n
. The structure of these calculi is explicitly described and the corresponding ad-invariant right ideals of ker are determined. In the limitq1 two of the 2n calculi forA
n–1
and one of the two calculi forB
n
,C
n
andD
n
contain the ordinary classical differential calculus on the corresponding Lie group as a quotient. 相似文献
24.
Konrad Schumacher 《Journal of Mathematical Analysis and Applications》1981,80(1):261-290
In this paper we will be concerned with the abstract semilinear equation x(Φ)(t) = Ax(Φ)(t) + F(t, xt(Φ)), t ? τ, xτ(Φ) = Φ, where A represents the infinitesimal generator of a linear C0-semigroup in a Banach space and x~(Φ) denotes the segment of the solution x due to the initial function Φ taken from ?∞ up to t. Conditions for existence, continuous dependence, and regularity of solutions are given which are independent of the topology of the phase space, as well as conditions which guarantee the compactness of bounded orbits, even if exp(At) is not compact for t > 0. 相似文献
25.
Hrabovsky M. Konrad M. Kopecky V. Sember V. 《IEEE transactions on plasma science. IEEE Nuclear and Plasma Sciences Society》1997,25(5):833-839
Experimental investigation of an electric arc stabilized by a water vortex was carried out in a DC arc plasma torch for the power range 90-200 kW. Volt-ampere characteristics of the arc as well as the power balance were determined separately for the part of the arc column stabilized by water and for the remaining part between the nozzle exit and the external anode. The temperature of arc plasma close to the nozzle exit was determined by emission spectroscopy. Negatively biased electric probes in the ion collecting regime were used for determination of the plasma flow velocity. The measured temperatures up to 27000 K, and velocities up to 7 km/s are higher than the values commonly reported for plasma torches with DC arcs stabilized by a gas flow. Mass and energy balances within the arc chamber were determined from the experimental results. The radial transport of the energy by radiation was identified as a decisive process controlling the arc and plasma properties. The balance of radial energy transport was studied. The ratio of energy spent for evaporation of the water to the energy absorbed in the evaporated mass is very low in the water stabilized arc. This is the principal cause of high plasma temperatures and velocities found by the measurements 相似文献
26.
For two covariant differential *-calculi, the twisted cyclic cocycle associated with the volume form is represented in terms of commutators
for some self-adjoint operator
and some *-representation of the underlying *-algebra. 相似文献
27.
International comparative studies such as TIMSS and PISA have had a considerable influence on the national educational policy in many countries. In Austria, as a reaction to the disappointing TIMSS 1995 results at the upper secondary level, a national initiative with the aim to foster mathematics and science education was launched in 1998: the IMST project. Due to specific challenges of the Austrian educational system, it has undergone several adaptations, but is still running. One of the project’s basic interventions is to promote teachers’ investigation into their own work. It is assumed that this supports the teachers’ critical stance towards innovation and inquiry, which in turn is an important basis for disseminating inquiry-based learning. A general look at the whole project and a specific look into one research project of IMST are used as opportunities to reflect on the complex interconnection and natural tension between the goal of promoting students’ IBL and its sustainable dissemination on a large scale. The paper introduces the project’s theoretical framework and genesis, provides exemplary research results, and reflects on its impact. The paper finishes with five “lessons learnt” from IMST. 相似文献
28.
Balázs Csikós György Kiss Konrad J. Swanepoel P. Oloff de Wet 《Periodica Mathematica Hungarica》2009,58(2):129-138
A family {A
i
| i ∈ I} of sets in ℝ
d
is antipodal if for any distinct i, j ∈ I and any p ∈ A
i
, q ∈ A
j
, there is a linear functional ϕ:ℝ
d
→ ℝ such that ϕ(p) ≠ ϕ(q) and ϕ(p) ≤ ϕ(r) ≤ ϕ(q) for all r ∈ ∪
i∈I
A
i
. We study the existence of antipodal families of large finite or infinite sets in ℝ3.
The research was supported by the Hungarian-South African Intergovernmental Scientific and Technological Cooperation Programme,
NKTH Grant no. ZA-21/2006 and South African National Research Foundation Grant no. UID 61853, as well as Hungarian National
Foundation for Scientific Research Grants no. NK 67867, no. T47102, and no. K72537. 相似文献
29.
Gabasch H Hayek K Klötzer B Knop-Gericke A Schlögl R 《The journal of physical chemistry. B》2006,110(10):4947-4952
The decomposition of ethene on the Pd(111) surface was studied at effective pressures in the 10(-8) to 10(-7) mbar range and at sample temperatures between 300 and 700 K, using an effusive capillary array beam doser for directional adsorption, LEED, AES, temperature programmed reaction, and TDS. In the temperature range of 350-440 K increasingly stronger dehydrogenation of the ethene molecule is observed. Whereas at 350 K an ethylidyne adlayer is still present after adsorption, already at temperatures around 440 K complete coverage of the surface by carbon is attained, while the bulk still retains the properties of pure Pd. Beyond 440 K a steady-state surface C coverage is established, which decreases with temperature and is determined by detailed balancing between the ethene gas-phase adsorption rate and the migration rate of carbon into the Pd bulk. This process gives rise to the formation of a "partially carbon-covered Pd(x)C(y) surface". Above 540 K the surface-bulk diffusion of adsorbed carbon becomes fast, and in the UHV experiment the ethene adsorption rate becomes limited by the ethene gas-phase supply. The carbon bulk migration rate and the steady-state carbon surface coverage were determined as a function of the sample temperature and the ethene flux. An activation energy of 107 kJ mol(-1) for the process of C diffusion from surface adsorption sites into the subsurface region was derived in the temperature range of 400-650 K by modeling the C surface coverage as a function of temperature on the basis of steady-state reaction kinetics, assuming a first-order process for C surface-subsurface diffusion and a second-order process for C(ads) formation by dissociative C2H4 adsorption. 相似文献
30.
Waldemar Konrad Christian Fengler Sarrah Putwa Christopher Barner‐Kowollik 《Angewandte Chemie (International ed. in English)》2019,58(21):7133-7137
An advanced light‐induced avenue to monodisperse sequence‐defined linear macromolecules via a unique photochemical protocol is presented that does not require any protection‐group chemistry. Starting from a symmetrical core unit, precision macromolecules with molecular weights up to 6257.10 g mol?1 are obtained via a two‐monomer system: a monomer unit carrying a pyrene functionalized visible light responsive tetrazole and a photo‐caged UV responsive diene, enabling an iterative approach for chain growth; and a monomer unit equipped with a carboxylic acid and a fumarate. Both light‐induced chain growth reactions are carried out in a λ‐orthogonal fashion, exciting the respective photosensitive group selectively and thus avoiding protecting chemistry. Characterization of each sequence‐defined chain (size‐exclusion chromatography (SEC), high‐resolution electrospray ionization mass spectrometry (ESI‐MS), and NMR spectroscopy), confirms the precision nature of the macromolecules. 相似文献