Atomic mass of145Eu derived from relative PK-ratios

The level scheme of⁹³Ru has been studied in⁴⁰Ca induced reactions on Ni and Fe targets. Two new levels feeding the known 17/2⁺ state have been established: an isomeric level (T_1/2=2.6 us) at 2081.5 keV with J=21/2⁺ and a level at 2103 keV, presumably a 17/2^? state. The B(E2; 21/2⁺→17/2⁺) value and the level scheme are compared to shell model predictions.     

Substitution Delone sets with pure point spectrum are inter-model sets

The paper establishes an equivalence between pure point diffraction and certain types of model sets, called inter-model sets, in the context of substitution point sets and substitution tilings. The key ingredients are a new type of coincidence condition in substitution point sets, which we call algebraic coincidence, and the use of a recent characterization of model sets through dynamical systems associated with the point sets or tilings.     

Atomic cavity with light-induced mirrors

We consider a possibility of creating an atomic cavity on the basis of reflection of atoms from a laser field. The main parameters of cavity such as maximum and minimum atomic velocity, cavity stability, scheme of atomic injection, maximum atomic density were defined. It was shown that a high degeneracy of atoms (1) can be achieved in such cavity.     

Atomic nanofabrication with complex light fields

The method of neutral atom lithography allows one to transfer to a substrate a 2D intensity modulation of an atomic beam imposed by an inhomogeneous light field. The complexity of the pattern depends on the properties of the light field constructed from the superposition of multiple laser beams. For the design of suitable light fields we present a mathematical model with a corresponding numerical simulation of the so-called inverse problem. Furthermore, details of an experiment carried out with a holographically reconstructed light field are discussed. PACS 02.60.Pn; 42.40.My; 42.40.Pa; 42.50.Vk     

Two-Photon Micromaser with Initial Atomic Coherence

We investigate the quantum dynamics of a two-photon micromaser pumped by atoms injected in the superposition state of the upper and intermediate levels. We simulate a master equation governing the system by the Monte Carlo wavefunction approach and analyse the steady-state behaviour as a function of the atomic transit time. The atomic coherence can effectively enhance the intensity and sub-Poissonian of the cavity field as compared with the atomic mixture. It is also discovered that the phase of the cavity field can be shifted by adjusting the detuning between the atom and field. This result shows that it is possible to manipulate the phase of the cavity field by detuning, due to atomic coherence.     

Representation of complete ortholattices by sets with orthogonality

We consider an algebraic closure operator induced by orthogonality on an arbitrary set and we investigate some problems with regard to the orthomodular law for a complete lattice of closed subsets.     

Limit sets ofS-unimodal maps with zero entropy

One-dimensional mappings at the limit of period doubling are studied in this paper without the use of the renormalization theory of Feigenbaum and others. The principal result is that the attracting part of the nonwandering set is a Cantor set of measure zero under the additional assumption that the map has negative Schwarzian derivative.     

Fluorescent optical tomography with large data sets

In recent years, optical tomography (OT) of highly scattering biological samples has increasingly relied on noncontact CCD-based imaging devices that can record extremely large data sets, with up to 10(9) independent measurements per sample. Reconstruction of such data sets requires fast algorithms. The latter have been developed and applied experimentally in our previous work to imaging of the intrinsic absorption coefficient of highly scattering media. However, it is widely recognized that the use of fluorescent contrast agents in OT has the potential to significantly enhance the technique. We show that the algorithms previously developed by us can be modified to reconstruct the concentration of fluorescent contrast agents.     

Stability of Atomic Simulations with Matching Boundary Conditions

We explore the stability of matching boundary conditions in one space dimension, which was proposed recently for atomic simulations (Wang and Tang, Int. J. Numer. Mech. Eng., 93 (2013), pp. 1255-1285). For a finite segment of the linear harmonic chain, we construct explicit energy functionals that decay along with time. For a nonlinear atomic chain with its nonlinearity vanished around the boundaries, an energy functional is constructed for the first order matching boundary condition. Numerical verifications are also presented.     

用发射光谱分析法检测微量贵金属

Ｐｔ,Ｐｄ,Ｒｈ,Ａｕ能溶于王水及盐酸加双氧水中,而Ｒｈ溶于热硫酸或浓盐酸加氯酸钙,试验中可用王水溶矿,在王水或盐酸介质和氯化亚锡存在下用负载二苯基硫脲的混合碳粉富集痕量的Ｐｔ（Ⅱ）、Ｐｄ（Ⅱ）,Ｒｈ（Ⅰ）,Ａｕ（Ⅱ）络合物,吸附载体灰化后用发光谱测定,测定灵敏度达到了１×１０＾－９。     

Two-Dimensional Talbot Effect with Atomic Density Gratings

We report the experimental observation of two-dimensional Talbot effect when a resonance plane wave interacts with a two-dimensional atomic density grating generated by standing wave manipulation of ultracold Bose gases.Clear self-images of the grating and sub-images with reversed phase or fractal patterns are observed. By calculating the autocorrelation functions of the images, the behavior of periodic Talbot images is studied. The Talbot effect with two-dimensional atomic density grating expands the applications of the Talbot effect in a wide variety of research fields.     

Atom Lithography with a Chromium Atomic Beam

Direct write atom lithography is a new technique in which resonant light is used to pattern an atomic beam and the nanostructures are formed when the atoms deposit on the substrate. We design an experiment setup to fabricate chromium nanolines by depositing an atomic beam of ^52Cr through an off-resonant laser standing wave with the wavelength of 425.55 nm onto a silicon substrate. The resulting nanolines exhibit a period of 215±3 nm with height of I nm.     

Atomic refinement with correlated solid-state NMR restraints

The orientation data provided by solid-state NMR can provide a great deal of structural information about membrane proteins. The quality of the information provided is, however, somewhat degraded by sign degeneracies in measurements of the dipolar coupling tensor. This is reflected in the dipolar coupling penalty function used in atomic refinement, which is less capable of properly restraining atoms when dipolar sign degeneracies are present. In this report we generate simulated solid-state NMR data using a variety of procedures, including back-calculation from crystal structures of alpha-helical and beta-sheet membrane proteins. We demonstrate that a large fraction of the dipolar sign degeneracies are resolved if anisotropic dipolar coupling measurements are correlated with anisotropic chemical shift measurements, and that all sign degeneracies can be resolved if three data types are correlated. The advantages of correlating data are demonstrated with atomic refinement of two test membrane proteins. When refinement is performed using correlated dipolar couplings and chemical shifts, perturbed structures converge to conformations with a larger fraction of correct dipolar signs than when data are uncorrelated. In addition, the final structures are closer to the original unperturbed structures when correlated data are used in the refinement. Thus, refinement with correlated data leads to improved atomic structures. The software used to correlate dipolar coupling and chemical shift data and to set up energy functions and their derivatives for refinement, CNS-SS02, is available at our web site.     

Atomic qubit manipulations with an electro-optic modulator

We report new techniques for driving high-fidelity stimulated Raman transitions in trapped-ion qubits. An electro-optic modulator induces sidebands on an optical source, and interference between the sidebands allows coherent Rabi transitions to be efficiently driven between hyperfine ground states separated by 14.53 GHz in a single trapped 111Cd+ ion.     

Atomic dynamics in liquids with competing interactions

The influence of the type of atomic interaction on the atomic dynamics is studied for liquid Na(x)Sn(1-x) (x = 0.9, 0.77, 0.57, 0.5, 0.33) alloys by cold neutron inelastic scattering. The dispersions obtained from the longitudinal current correlation function J(l)(Q,omega) show clear evidence for the dependence of the dynamics on the type of interaction (metallic, ionic, partly covalent) tuned by changing the composition of the alloy. For the first time, a second dispersion branch is observed in the total J(l)(Q,omega) around Q(p), the position of the principal peak of S(Q), for the Sn-rich compositions. The dynamic properties are discussed and compared to results of recent ab initio molecular dynamics simulations.     

REDOR with a relative full-echo reference

REDOR and REDOR-like 13C[19F] and 2H[19F] NMR experiments have been performed on lyophilized whole cells of Staphylococcus aureus. The bacteria were grown to maturity on media containing L-[13C(3)]alanine or L-[methyl-d(3)]alanine, and then complexed with the 4-fluorobiphenyl derivative of chloroeremomycin, an analogue of the widely used antibiotic, vancomycin. The position of the 19F of the drug bound in the bacterial cell wall was determined relative to L-alanine 13C and 2H labels in the peptidoglycan peptide stem that was closest to the fluorinated biphenyl moiety of the drug. These determinations were made by dipolar recoupling methods that do not require an absolute measurement of the REDOR full echo (the signal observed without rotor-synchronized dephasing pulses) of the labels in the peptide stem.     

Atomic clocks with suppressed blackbody radiation shift

We develop a concept of atomic clocks where the blackbody radiation shift and its fluctuations can be suppressed by 1-3 orders of magnitude independent of the environmental temperature. The suppression is based on the fact that in a system with two accessible clock transitions (with frequencies ν1 and ν2) which are exposed to the same thermal environment, there exists a "synthetic" frequency ν(syn) ∝ (ν1 - ε12ν2) largely immune to the blackbody radiation shift. For example, in the case of 171Yb+ it is possible to create a synthetic-frequency-based clock in which the fractional blackbody radiation shift can be suppressed to the level of 10(-18) in a broad interval near room temperature (300±15 K). We also propose a realization of our method with the use of an optical frequency comb generator stabilized to both frequencies ν1 and ν2, where the frequency ν(syn) is generated as one of the components of the comb spectrum.