On a canonical nine-body problem. Integrable Ermakov decomposition via reciprocal transformations

Here, a recently introduced nine-body problem is shown to be decomposable via a novel class of reciprocal transformations into a set of integrable Ermakov systems. This Ermakov decomposition is exploited to construct more general integrable nine-body systems in which the canonical nine-body system is embedded.     

Parameter identification for cracks in elastic plate structures based on remote strain fields

A method for the detection of cracks in plate structures is presented. In contrast to most of the common monitoring concepts taking advantage of the reflection of elastic waves at crack faces, the presented approach is based on the strain measured at different locations on the surface of the structure. This allows both the identification of crack position parameters, such as length, location and angles with respect to a reference coordinate system and the calculation of stress intensity factors (SIF). The solution of the direct problem is performed on the basis of the BFM (body force method). The inverse problem is solved applying the particle swarm optimization (PSO) algorithm. The BFM is based on the principle of linear superposition which allows the calculation of the strain field in a cracked body. The strain at an arbitrary point in the structure is replaced by the strain provided by body force doublets in the uncracked structure. The doublets as well as external loads are parameters which have to be determined solving the inverse problem by minimizing a fitness function, which is defined by a square sum of residuals between measured strain distributions and computed ones for an assumed crack. The PSO algorithm applied to the fitness function operates on the basis of a swarm of candidate solutions. Once knowing loading and crack parameters, the SIF can be determined.     

Preparation and formation mechanism of CdS nano-films via chemical bath deposition

CdS semiconductor nano-films were grown on ITO glass substrates by means of chemical bath deposition (CBD), with Cd(NO₃)₂ as Cd ion and (NH₂)₂CS as S ion sources. The concentration of Cd ions, deposition temperature, deposition time and post-treatment temperature have an impact on the formation of CdS nano-films. UV-vis absorption spectrum and atomic force microscope (AFM) images indicated that the change of concentration and post-treatment temperature may adjust the band-gap of CdS to obtain stable, homogeneous and compact films. Formation mechanism of the crystal nucleus and CdS film was also discussed. Active sites on the surface of ITO are critical to the formation of the crystal nucleus and a uniform and compact CdS nano-film. The active site and crystal nucleus are formed due to the comprehensive effect of electricity, thermodynamics and chemistry. __________ Translated from Journal of Jilin University (Science Edition), 2007, 45(1): 116–120 [译自: 吉林大学学报(自然科学版)]     

Nucleus Independent Chemical Shift (NICS) at Small Distances from the Molecular Plane: The Effect of Electron Density

When close to the molecular plane, the behavior of nucleus independent chemical shift (NICS) as a function of the distance from the molecular plane deviates from its behavior at larger distances. By using a dense grid of NICS-probes (BQs) it is shown that, when close to the molecular plane, maximal (absolute) NICS values are obtained above the atoms. These maxima move towards the center as the grid is elevated until the (absolute) maximum NICS is obtained at the center and stay there when the grid is further elevated. It is shown that this behavior is a result of the current density, which is influenced by the electron density, according to the Biot-Savart law, which, in turn, causes the induced magnetic field measured by the NICS. It is thus concluded that if magnetic aromaticity is studied, the NICS calculations should be carried out at a large enough distance so that only the π-ring current affects the NICS. At distances ≥2 Å, NICS(r)_π,zz=A+B*C^r. Using non-linear correlation for obtaining A, B and C and extrapolate to NICS(1)_π,zz and NICS(1.7)_π,zz is recommended as measures for aromaticity.     

Clinical chemistry without reagents? An infrared spectroscopic technique for determination of clinically relevant constituents of body fluids

A spectroscopic method based on attenuated total reflection Fourier-transform infrared (ATR-FTIR) spectroscopy has been developed for reagent-free analysis of blood and urine constituents in the clinical laboratory and for point-of-care-applications. Blood plasma, whole blood, and urine were analyzed without any sample preparation, such as drying, concentration, or enrichment. Sample volumes as small as 5 μL (a single drop of blood) can be used. Mathematical models, including partial least-squares regression, were used to construct a prediction model which can calculate the concentration of albumin, cholesterol, glucose, total protein, urea, and triglycerides in whole blood or blood plasma samples and the concentration of urea, uric acid, phosphate and creatinine in urine samples. The absolute precision and reproducibility of the prediction reached is sufficient for routine clinical analysis and is only limited by the precision of the reference analysis used for calibration. This was achieved by use of a large number of calibration samples (approx. 400 for blood samples and approx. 100 for urine samples) carefully selected for physiological and pathological range and for specific disease profiles.     

Neutrons produced by 1.22 GeV antiproton interactions with nuclei

Inclusive neutron energy spectra were measured by time of flight using 1.22 GeV antiprotons from LEAR, CERN, as projectiles and targets from natural Al, Cu, Ag, Ho, Ta, Au, Pb, Bi, U. The sum of two Maxwellian distributions was fitted to the spectra obtained at several forward and backward angles yielding neutron multiplicities M_i and slope or temperature parameters T _i for the low-energy (evaporative, i=1) and high-energy (pre-equilibrium,i=2) parts, respectively. M ₁ increases with A, proportional to the nuclear volume, and M ₂ is growing with A , proportional to the nuclear radius. The T parameters are nearly independent of A. The results are compared with previous multiplicity measurements with a neutron detector, intranuclear cascade calculations and neutron spectra from stopped antiproton annihilation on nuclei. With the measured proton spectra also the ratio of emitted neutrons to protons was determined for Au. Received: 25 February 2000 / Accepted: 19 May 2000     

De–excitation of compound nuclei with A around 56: reduction of the emission barriers for protons and alpha particles

This paper contributes to the discussion on the phenomena of the enhanced emission of low–energetic charged particles during compound nuclei decay. The decay of compound nuclei ⁵²Fe, ⁵⁶Ni, and ⁵⁹Cu was studied. Energy spectra and emission angles of evaporated charged particles were measured in coincidence with gamma rays to determine the corresponding evaporation residue nucleus. Additionally, evaporation residue distributions were determined with the Munich rf recoil spectrometer. In this way, detailed channel–specific evaporation data were obtained for theoretical analysis. We extracted evaporation barriers and compared them with corresponding fusion barriers. The main result was revealed to be a lowering of the evaporation barrier for protons and alpha particles relative to the fusion barriers. But the observed effect is not as intensive as reported in recent studies. Received: 15 June 1998 / Revised version: 5 November 1998     

A new high-spin isomer in 145Sm

A new high-spin isomer in ¹⁴⁵Sm was observed by in-beam γ-ray spectroscopy with the reaction ¹²²Sn(²⁷Al,3np) at 127 MeV performed at the Nordball multi-detector array in Roskilde. The excitation energy of the isomer was determined to be E _x= 11147 keV, and using the generalized centroid-shift method its half-life was found to be T _1/2= (7.4 ± 1.0) ns. Received: 23 October 1998     

丰质子核性质的研究

用相对论平均场理论研究了2sld壳丰质子核及其镜核的性质,理论计算结果与实验数据很好地符合.     

单核子在具有八极形变的平均势场中的混沌运动(Ⅱ)初始相干态空时演化中正则变量的期望值和测不准度的特征

研究了二维不对称谐振子的相干态在附加八极形变势作用下传播时,量子正则变量的期望值和测不准度的变化,发现量子混沌与相应的经典混沌完全对应地表现了多种性质.量子混沌的特征也与势能面的几何对称性,即势能面上负曲率的存在及负曲率的大小有关系.