排序方式: 共有37条查询结果,搜索用时 15 毫秒
1.
Wagner F Gruber O Lackner K Murmann HD Speth E Becker G Bosch HS Brocken H Cattanei G Dorst D Eberhagen A Elsner A Erckmann V Fussmann G Gehre O Gernhardt J Gierke Gv Glock E Grieger G Grigull P Haas G Hacker H Hartfuss HJ Jäckel H Jaenicke R Janeschitz G Junker J Karger F Kasparek W Keilhacker M Kick M Klüber O Kornherr M Kroiss H Kuehner M Lenoci M Lisitano G Maassberg M Mahn C Marlier S Mayer HM McCormick K Meisel D Mertens V Müller ER Müller Müller G Niedermeyer H Ohlendorf W 《Physical review letters》1986,56(20):2187-2190
2.
Tensor analyzing powers, T20, of outgoing α-particles in the 58Ni(, α)56Co reaction at detection angles near 0° have been measured for excited states in 56Co for beam energies of 6.75, 7.0, 7.5, 9.0 and 9.5 MeV. Thirty-seven spin-parity combinations for 56Co excited states have been deduced. Previous Jπ ambiguities for 11 of these states have been eliminated, and results in conflict with existing assignments for the levels at 3.235 and 3.378 MeV have been obtained. A search for 0+ states was carried out from angular distribution measurements at forward angles of the unpolarized (d, α) reaction. The combined results from this and previous experiments were found to be in reasonable agreement with calculated level schemes. 相似文献
3.
Araujo MH Hitchcock PB Nixon JF Kuehner U Stelzer O 《Chemical communications (Cambridge, England)》2003,(9):1092-1093
Hydrozirconation of the eta 2-phosphaalkyne complex [Pt(dppe)(eta 2-tBuCP)] with [ZrHCl(eta 5-C5H5)2], followed by treatment with the chlorophosphaalkene ClP=C(SiMe3)2 affords the eta 2-2,3-diphosphabutadiene complex [Pt(dppe)(eta 2-tBuC(H)=PP=C(SiMe3)2]. In the presence of [Pt(PPh3)2] the latter undergoes an addition reaction with water to afford the structurally characterised Pt(II) complex [Pt(dppe)(tBuCH2P(O)HPC(SiMe3)2]. 相似文献
4.
Increasing the autonomy of multi-agent systems or swarms for exploration missions requires tools for efficient information gathering. This work studies this problem from theoretical and experimental perspectives and evaluates an exploration system for multiple ground robots that cooperatively explore a stationary spatial process. For the distributed model, two conceptually different distribution paradigms are considered. The exploration is based on fusing distributively gathered information using Sparse Bayesian Learning (SBL), which permits representing the spatial process in a compressed manner and thus reduces the model complexity and communication load required for the exploration. An entropy-based exploration criterion is formulated to guide the agents. This criterion uses an estimation of a covariance matrix of the model parameters, which is then quantitatively characterized using a D-optimality criterion. The new sampling locations for the agents are then selected to minimize this criterion. To this end, a distributed optimization of the D-optimality criterion is derived. The proposed entropy-driven exploration is then presented from a system perspective and validated in laboratory experiments with two ground robots. The experiments show that SBL together with the distributed entropy-driven exploration is real-time capable and leads to a better performance with respect to time and accuracy compared with similar state-of-the-art algorithms. 相似文献
5.
N. Chai W.D. Kulatilaka S.V. Naik N.M. Laurendeau R.P. Lucht J.P. Kuehner S. Roy V.R. Katta J.R. Gord 《Applied physics. B, Lasers and optics》2007,88(1):141-150
We report the application of electronic-resonance-enhanced coherent anti-Stokes Raman scattering (ERE-CARS) for measurements
of nitric oxide concentration ([NO]) in three different atmospheric pressure flames. Visible pump (532 nm) and Stokes (591 nm)
beams are used to probe the Q-branch of the Raman transition. A significant resonance enhancement is obtained by tuning an
ultraviolet probe beam (236 nm) into resonance with specific rotational transitions in the (v’=0, v”=1) vibrational band of
the A2Σ+–X2Π electronic system of NO. ERE-CARS spectra are recorded at various heights within a hydrogen-air flame producing relatively
low concentrations of NO over a Hencken burner. Good agreement is obtained between NO ERE-CARS measurements and the results
of flame computations using UNICORN, a two-dimensional flame code. Excellent agreement between measured and calculated NO
spectra is also obtained when using a modified version of the Sandia CARSFT code for heavily sooting acetylene-air flames
(φ=0.8 to φ=1.6) on the same Hencken burner. Finally, NO concentration profiles are measured using ERE-CARS in a laminar,
counter-flow, non-premixed hydrogen-air flame. Spectral scans are recorded by probing the Q1 (9.5), Q1 (13.5) and Q1 (17.5) Raman transitions. The measured shape of the [NO] profile is in good agreement with that predicted using the OPPDIF
code, even without correcting for collisional effects. These comparisons between [NO] measurements and predictions establish
the utility of ERE-CARS for detection of NO in flames with large temperature and concentration gradients as well as in sooting
environments.
PACS 07.88.+y; 42.62.Fi; 42.65.Dr 相似文献
6.
A.A. Pilt J.A. Kuehner Ren-cheng Shang M.A.M. Shahabuddin A. Trudel 《Physics letters. [Part B]》1981,100(2):114-116
We point out that, in many cases, anti-analogue 0+ states cannot be populated in )d, α) reactions. This results from the particular isospin structure of the anti-analogue, and may well be new, useful, tool to aid in the identification of such states. A particular example arising in the 42 Ca (d, α) reaction is generalized in a straightforward way. 相似文献
7.
The 68Zn(, α)66Cu reaction populating low-lying states in 66Cu has been studied at θlab = 4° using deuteron beams in the energy range 9.0 to 10.5 MeV. Tensor analyzing powers were calculated and natural- or unnatural-parity assignments were made for thirteen states in 66Cu. By combining these results with existing limits unambiguous Jπ assignments of 2+, 2+, 2+ and 1+ have been made for the levels at 186, 465, 822 and 1344 keV respectively. The previous tentative assignments to seven other levels have been confirmed while that for the 1247 keV level has been shown to be incorrect. The identification of the quartet of levels based on the configuration has been confirmed. 相似文献
8.
J.A. Kuehner J. Szücs P. Ikossi A.M. McDonald D.T. Petty 《Physics letters. [Part B]》1977,66(1):32-34
A new technique for gamma-ray angular correlation measurements using tensor polarized deuterons is illustrated with the reaction. The 4.77 MeV level of 22Na is assigned Jπ = 3+ and the transition to the 1.95 MeV level is determined to be pure magnetic dipole. 相似文献
9.
The reaction 18O(d, α)16N has been studied using a tensor-polarized deuteron beam at incident energies of 8.50, 9.25, 10.00, 10.30, 10.75 and 11.30 MeV. From measurement of the tensor analysing power of the reaction when the α-particles are emitted near 0°, spin-parity combinations have been deduced for thirteen levels in 16N up to 6.2 MeV excitation. These results, together with previous work, lead to new and unambiguous spin and parity assignments for four of these levels. 相似文献
10.
Joel P. Kuehner F. Andrew Tessier Jr. Allan Kisoma Jonathan G. Flittner Michael R. McErlean 《Experiments in fluids》2010,48(3):421-430
Instantaneous temperature measurements were obtained in an underexpanded jet using electrostrictive laser-induced gratings.
Evaluation of the technique under static, low-pressure conditions provided a baseline uncertainty or precision for single-shot
temperature measurements of 4.4% of the local mean temperature, which represents the minimum detectable temperature fluctuation.
The underexpanded jet was operated at a nozzle pressure ratio of 2.39 and a fully expanded jet Mach number of 1.19. Data were
acquired along the centerline and over two radial traverses through the shear layer. Mean temperature data agree well with
expectations, describing the shock-cell structure and the compressible shear layer. The growth in shear-layer width with downstream
distance can be identified in the mean and fluctuating temperature measurements. Temperature fluctuations are near the baseline
detection limit in the jet core and surrounding ambient air, and reach a maximum in the shear layer. The temperature fluctuation
measurements compare well with previous computational and experimental work, confirming the application of the technique to
a turbulent, supersonic flow. 相似文献