Radiation dose of workers originating from radon in the show Cave of Tapolca,Hungary

In the last few decades attention has been given to improve workplace conditions, primarily to reduce the different health risks. In the air that accumulates in underground workplaces radon may constitute one of the health risks. The radon concentration in the show cave in Tapolca is especially high in summer months, with the annual average in the year 2005 being 7227 Bq/m³, in 2006 8591 Bq/m³. The radon concentration was found to be independent on the location of the measurement. Its value was rather similar for working hours and for the total period. The hours spent in the cave by the workers depend on the number of visitors. The radiation dose, estimated on the basis of personal dosimeters, is significant for those working there especially, employed during the whole year. Taking into consideration the actual working hours and the equilibrium factor, F = 0.4, given in the literature, it approaches and even exceeds the dose limit of 20 mSv/year. With a well organized work schedule, as well as the employment of outside workers during the summer period, the dose limit of 20 mSv/year can probably be maintained. However, on the basis of recent measurements, the actual equilibrium factor was determined to be F = 0.5, which in turn means a further 25% increase in the dose effect.     

An application of fragment interaction analysis based on local MP2

We have developed a method named ‘fragment interaction analysis based on local MP2’ (abbreviated as FILM). This method enables us to decompose the interaction energy associated with dispersion interactions into contributions of localized occupied orbitals. In this study, the basis set dependence of the results derived from FILM was examined. The results suggested that the individual ratio of pair correlation energies of selected orbital pairs to the total dispersion interaction was almost independent of the basis set size. As an illustrative example, detailed analysis was performed on the human immunodeficiency virus type 1 protease complexed with lopinavir molecule.     

Fundamental imaging properties of transillumination laser computed tomography based on coherent detection imaging method.

The coherent detection imaging (CDI) method uses the optical heterodyne detection technique. CW and single frequency lasers having long coherence lengths are used to exploit the maximum advantages of heterodyne detection, such as high directionality, selectivity and sensitivity. The CDI method based on optical heterodyne detection enables selective filtering of the directional coherence-retaining emergent photons, which leads to image reconstruction from projections, similar to X-ray computed tomography (CT). So far we have demonstrated the advantages and capabilities of the measurement technique for transillumination optical computed tomography in biomedicine. Here, we investigate the fundamental imaging properties of CDI method, such as its high directionality and quantitativeness, with preliminary physical phantom experiments. The results show that the CDI method satisfies the requirements for CT reconstruction under the first order approximation, and enables quantitative measurements in the sense that the relationship between estimated and actual concentration retains a satisfactory linearity.     

Water-soluble constituents of ajowan.

From the water-soluble portion of the methanol extract of the fruit of Carum ajowan (ajowan), which has been used as a spice and medicine, 25 compounds, including five new monoterpenoid glucosides, a new monoterpenoid, two new aromatic compound glucosides, and two new glucides, were obtained. Their structures were clarified by spectral investigation.     

Accurate frequency atlas of molecular iodine near 532 nm measured by an optical frequency comb generator

An optical frequency comb generator (OFCG) at 1064 nm with a modulation frequency of 2 GHz is developed for an accurate optical frequency link between iodine absorption lines near 532 nm. With the OFCG, we have measured frequency differences between seventeen ¹²⁷I₂ transitions with a measurement uncertainty of about 240 Hz (relatively 4.3×10⁻¹³), which is mainly contributed from the frequency repeatability of iodine-stabilized Nd:YAG lasers. The measured transitions provide an attractive frequency reference network and are excellent candidates for the practical realization of the meter.     

QED radiative correction for the single-W production using a parton shower method

A parton shower method for the photonic radiative correction is applied to single W-boson production processes. The energy scale for the evolution of the parton shower is determined so that the correct soft-photon emission is reproduced. Photon spectra radiated from the partons are compared with those from the exact matrix elements, and show a good agreement. Possible errors due to an inappropriate energy-scale selection or due to the ambiguity of the energy-scale determination are also discussed, particularly for the measurements on triple gauge couplings. Received: 22 February 2001 / Published online: 11 May 2001     

μ+SR Study of Ordering Phenomena in the Heavy-Fermion State of Ce3Pd20Ge6

Magnetic and quadrupolar ordering phenomena in a Ce₃Pd₂₀Ge₆ single crystal have been investigated by muon spin rotation/relaxation (μ⁺SR) spectroscopy. We have observed spontaneous precession of muons in zero-field below T _N =0.7 K in the antiferromagnetic state. The precession frequency follows the power law: ν(T)=ν(0)(1−T/T _N ) ⁿ . The exponent n=0.43(2) is close to the mean-field value of 0.5. The muon longitudinal spin relaxation rate 1/T ₁ is found to be nearly independent of temperature in the range of 0.3 to 2 K, i.e., across either T _N or T _Q =1.2 K, the quadrupolar ordering temperature. Two likely mechanisms for the temperature independent behavior of 1/T ₁ are suggested. This revised version was published online in September 2006 with corrections to the Cover Date.