Solutions of Einstein's field equations related to Jacobi's inversion problem

A new class of exact solutions to the axisymmetric and stationary vacuum Einstein equations containing n arbitrary complex parameters and one arbitrary real solution of the axisymmetric three-dimensional Laplace equation is presented. The solutions are related to Jacobi's inversion problem for hyperelliptic Abelian integrals.     

Self-consistent description of finite nuclei based on a relativistic quark model

Relativistic Hartree equations for spherical nuclei have been derived from a relativistic quark model of the structure of bound nucleons which interact through the (self-consistent) exchange of scalar (σ) and vector (ω and ϱ) mesons. The coupling constants and the mass of the σ-meson are determined from the properties of symmetric nuclear matter and the rms charge radius in ⁴⁰Ca. Calculated properties of static, closed-shell nuclei from ¹⁶O to ²⁰⁸Pb are compared with experimental data and with results of Quantum Hadrodynamics (QHD). The dependence of the results on the nucleon size and the quark mass is investigated. Several possible extensions of the model are also discussed.     

Facile room-temperature coprecipitation of uniform barium chlorapatite nanoassemblies as a host photoluminescent material

As an emerging host phosphor material, barium chlorapatite (Ba₅(PO₄)₃Cl), is attracting growing attention. However, rare earth-doped Ba₅(PO₄)₃Cl phosphors have mainly been obtained via high temperature-based, energy-consuming techniques. In this contribution, we developed a straightforward, facile room-temperature coprecipitation method in the presence of a specific amount of ethylenediaminetetraacetic acid disodium salt that provided Ba₅(PO₄)₃Cl nanoparticles self-assembled to construct uniform Ba₅(PO₄)₃Cl nanoassemblies (diameter: 80–120 nm) as well as rare earth Tb³⁺-doped Ba₅(PO₄)₃Cl:xTb³⁺ nanophosphors. The nanoassemblies were transparent within the ultraviolet and visible spectral range. The Ba₅(PO₄)₃Cl:xTb³⁺ nanophosphors exhibited four emission peaks under 228-nm excitation, and the optimal doping amount of Tb³⁺ was 4.0%. In contrast to traditional energy-consuming, high-temperature techniques, the facile room-temperature coprecipitation method developed here represents an attractive alternative route to obtain uniform Ba₅(PO₄)₃Cl nanoassemblies and Ba₅(PO₄)₃Cl:xTb³⁺ nanophosphors that are candidate luminescent hosts.     

A vision-based hybrid particle tracking velocimetry (PTV) technique using a modified cascade correlation peak-finding method

A novel technique for particle tracking velocimetry is presented in this paper to overcome the issue of overlapping particle images encountered in the flows with high particle density or under volumetric illumination conditions. To achieve this goal, algorithms for particle identification and tracking are developed based on current methods and validated with both synthetic and experimental image sets. The results from synthetic image tests show that the particle identification algorithm is able to resolve overlapped particle images up to 50?% under noisy conditions, while keeping the root mean square peak location error under 0.07?pixels. The algorithm is also robust to the size changes up to a size ratio of 5. The tracking method developed from a classic computer vision matching algorithm is capable of capturing a velocity gradient up to 0.3 while maintaining the error under 0.2?pixels. Sensitivity tests were performed to describe the optimum conditions for the technique in terms of particle image density, particle image sizes and velocity gradients, also its sensitivity to errors of the PIV results that guide the tracking process. The comparison with other existing tracking techniques demonstrates that this technique is able to resolve more vectors out of a dense particle image field.     

At the crossroad of the search for spontaneous radiation and the Orch OR consciousness theory

In this paper we perform a critical analysis of the Orch OR consciousness theory at the crossroad with the newest experimental results coming from the search for spontaneous radiation predicted by the simplest version of gravity-related dynamical collapse models. We conclude that Orch OR theory, when based on the simplest version of gravity-related dynamical collapse, is highly implausible in all the cases analyzed. We discuss the implications of our findings, the limitations, and future plans toward the development of more realistic gravity-related collapse models.     

A highly stereoselective synthesis of d-erythrose derivatives by one-carbon homologation of 2,3-O-isopropylidene-d-glyceraldehyde with (R)-methyl p-tolyl sulfoxide

A highly diastereoselective three-step synthesis of 2-O-benzyl-3,4-O-isopropylidene-d-erythrose 9 is described (de >98%; 50% overall yield) starting from d-glyceraldehyde acetonide and (R)-methyl p-tolyl sulfoxide. Treatment of 9 with trifluoroacetic acid gives 2-O-benzyl-d-erythrofuranose.     

Use of scanning reference electrode technique for characterizing pitting and general corrosion of carbon steel in neutral media

The scanning reference electrode technique (SRET) was used to characterize the corrosion behavior of carbon steel in the NaNO₂-containing chloride solution and tap water. In 10⁻³ MNaNO₂+10⁻³ MNaCl+10⁻³ MNa₂SO₄ solution, the passivated carbon steel surface suffered the pitting. In this case, the size of anodic and cathodic areas on the corroding surface varied with the exposed time, but anodic and cathodic sites did not change. On the contrary, the carbon steel was corroded generally in the tap water. The localized anodes and cathodes on the corroding surface were not fixed but movable with the exposed time during the whole corrosion process, and the “movable anodes” can be in situ monitored and momentarily identified by SRET measurements.     

双奇核中πi_(13/2)νi_(13/2)2-准粒子转动带旋称反转研究

利用重离子熔合蒸发反应和在束γ谱学实验方法研究了双奇核176,178Ir和182 Au的高自旋态结构 ,在这 3个双奇核中观测到了基于πi13 2 νi13 2 准粒子组态下的转动带 .以能级间隔系统学为判据 ,对184Au核中πi13 2 νi13 2 转动带能级自旋进行了指定 .指出176,178Ir和182 ,184Au 4个双奇核的πi13 2 νi13 2 转动带在低自旋区均出现旋称反转 .对πi13 2 νi13 2 转动带旋称反转现象进行了定性的讨论 .用推转壳模型对πh9 2 νi13 2 带和πi13 2 νi13 2 带能级结构进行了理论研究 ,发现当采用形变和对力自洽计算后 ,从理论上可以定性地解释两个半退耦带出现的旋称反转现象