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221.
PF-compact spaces are defined. Every almost realcompact space is PF-compact and every separable PF-compact space is almost realcompact. Nonetheless in the constructible universe V = L, a space of cardinality ?1 is PF-compact if, and only if, the closure of each of its countable subsets is almost realcompact, and ω1 is hereditarily PF-compact. 相似文献
222.
G.?Folger V.?N.?Ivanchenko J.?P.?WellischEmail author 《The European Physical Journal A - Hadrons and Nuclei》2004,21(3):407-417
The Binary Cascade introduces a novel approach towards intra-nuclear cascade calculations. Like many QMD codes, it uses a detailed 3-dimensional model of the nucleus, and is based exclusively on binary scattering between reaction participants and nucleons within this nuclear model. Like a classical cascade, it uses optical potentials to describe the time evolution of particles passing through the nuclear medium. In the present paper we introduce the model, and investigate its predictive power for hadron spectra in nucleon nuclear reactions final states.Received: 19 December 2003, Revised: 5 March 2004, Published online: 7 September 2004PACS:
21.60.Ka Nuclear structure: Monte Carlo models - 24.10.Lx Nuclear reactions: general: Monte Carlo simulations (including hadron and parton cascades and string breaking models) 相似文献
223.
224.
We study some categorical aspects of quasi-uniform spaces (mainly separation and epimorphisms) via closure operators in the sense of Dikranjan, Giuli, and Tholen. In order to exploit better the corresponding properties known for topological spaces we describe the behaviour of closure operators under the lifting along the forgetful functor T from quasi-uniform spaces to topological spaces. By means of appropriate closure operators we compute the epimorphisms of many categories of quasi-uniform spaces defined by means of separation axioms and study the preservation (reflection) of epimorphisms under the functor T. 相似文献
225.
Sophie Hoenke Martin A. Christoph Sander Friedrich Niels Heise Benjamin Brandes Hans-Peter Deigner Ahmed Al-Harrasi Ren Csuk 《Molecules (Basel, Switzerland)》2021,26(7)
Pentacyclic triterpenoids oleanolic acid, ursolic acid, betulinic acid, and platanic acid were acetylated and converted into several amides 9–31; the cytotoxicity of which has been determined in sulforhodamine B assays employing seral human tumor cell lines and nonmalignant fibroblasts. Thereby, a betulinic acid/trans-1,4-cyclohexyldiamine amide showed excellent cytotoxicity (for example, EC50 = 0.6 μM for HT29 colon adenocarcinoma cells). 相似文献
226.
Control of the charge state of metal atoms on thin MgO films 总被引:1,自引:0,他引:1
Sterrer M Risse T Martinez Pozzoni U Giordano L Heyde M Rust HP Pacchioni G Freund HJ 《Physical review letters》2007,98(9):096107
The arrangement of single gold and palladium atoms deposited on the surface of a 3 monolayer thin film of MgO was investigated using low-temperature scanning tunneling microscopy. While Pd atoms are arranged in a random fashion, Au forms an ordered array on the surface. The long-range ordering as well as the scanning tunneling microscopy appearance of single Au atoms on a 3 monolayer thin MgO film can be explained by partial charge transfer from the substrate to Au atoms as predicted recently by density functional theory calculations [Phys. Rev. Lett. 94, 226104 (2005)10.1103/PhysRevLett.94.226104]. In contrast with that, Au atoms on a thick film were found to be essentially neutral. 相似文献
227.
Lebedev O Nilles HP Raby S Ramos-Sánchez S Ratz M Vaudrevange PK Wingerter A 《Physical review letters》2007,98(18):181602
We study possible correlations between properties of the observable and hidden sectors in heterotic string theory. Specifically, we analyze the case of the Z6-II orbifold compactification which produces a significant number of models with the spectrum of the supersymmetric standard model. We find that requiring realistic features does affect the hidden sector such that hidden sector gauge group factors SU(4) and SO(8) are favored. In the context of gaugino condensation, this implies low energy supersymmetry breaking. 相似文献
228.
Hopkins WS Loock HP Cronin B Nix MG Devine AL Dixon RN Ashfold MN 《The Journal of chemical physics》2007,127(6):064301
The laser-induced photodissociation of formaldehyde in the wavelength range 309相似文献
229.
230.
Proton-conducting polymer membranes are utilized as the solid electrolyte in low temperature polymer electrolyte fuel cells (PEFC), which are efficient energy converters. We have selected the process of radiation grafting and subsequent sulfonation to prepare novel membranes because of its feasibility as a low cost production method. Investigations of the two first preparations steps, i.e., irradiation and grafting, lead to insight concerning the optimization of these two steps and the dependence of the final membrane properties on the various preparation parameters. 相似文献