Environmental gamma radiation measurements in Bangladeshi houses

Indoor gamma dose rate in air measured using TLDs in the Dhaka district is not wide ranging and follows a normal distribution with an arithmetic mean of $\text{1.54±0.26}\text{mGy}\text{y}{}^{\mathrm{-1}}$. The result has been compared with those found by other investigators for different locations of the world. Measurements were made on a monthly basis for a year period, and a sinusoidal variation of monthly indoor gamma radiation of the type: $\text{d=160+65}\text{cos}\text{π/6}\text{(m−1)}$, where d is the indoor dose rate $\text{(}\text{nGy}\text{h}{}^{\mathrm{-1}}\text{)}$ and m the month. This might be due to the seasonally varied air exchange rates of the houses. The average annual effective dose and the collective dose equivalent for the residents were estimated to be $\text{0.86}\text{mSv}$ and $\text{172.20}\text{man}$-Sv, respectively, based on the indoor gamma exposure.     

Microwave spectra of D217O and D218O

Forty lines of the microwave spectra of D₂¹⁷O and D₂¹⁸O have been measured in the region from 8 to 400 GHz and analyzed according to Watson's centrifugal distortion theory. Comparison of the results obtained for D₂¹⁶O, D₂¹⁷O, and D₂¹⁸O demonstrates their internal consistency. The transferability of the parameters according to the isotopic substitution rules is evidence for the validity of the model chosen for the study of the ground state of heavy water.The effective rotational constants deduced from the observed spectra are very close to the values calculated using Oka's second order theory. The values obtained in MHz are:

$\text{A = 456766.9,}\text{B = 218041.0,}\text{C = 144701.5}\text{(D}{}_2{}^{17}\text{O;)}$

$\text{A = 451891.9,}\text{B = 218045.2,}\text{C = 144201.7}\text{(D}{}_2{}^{18}\text{O;).}$

The hyperfine structure of the D₂¹⁷O lines has been analyzed using as a reference the corresponding quadrupole coupling tensor of HD¹⁷O with the appropriate rotation. The values of χ_gg in MHz used for the analysis are:

$\text{x}{}_{\mathrm{\chi \chi }}\text{= - 1.2104,}\text{x}{}_{\mathrm{yy}}\text{= 10.1068,}\text{x}{}_{\mathrm{zz}}\text{= - 8.8964.}$

     

The centrifugal distortion constants of disulfur monoxide

The microwave spectrum of the molecular transient disulfur monoxide, S₂O, has been reexamined and the microwave measurements have been extended into the millimeterwave region. From the present data, the following ground-state rotational constants and quartic distortion constants have been obtained (MHz):

$\text{A = 41915.44,}\text{B = 5059.07,}\text{C = 4507.19}$

$\text{δ}{}_{\mathrm{J}}\text{= 1.895 X 10}{}^{\mathrm{?}}\text{, δ}{}_{\mathrm{JK}}\text{= ?3.192 X 10}{}^{\mathrm{?2}}\text{,}\text{δ}{}_{\mathrm{K}}\text{= 1.197 X 10}{}^0$

$\text{δ}{}_{\mathrm{J}}\text{= 3.453 X 10}{}^{\mathrm{?4}}\text{and δ}{}_{\mathrm{K}}\text{= 1.223 X 10}{}^{\mathrm{?2}}$

The centrifugal distortion constants obtained from the rotational spectrum are used to discuss the vibrational spectrum of disulfur monoxide.     

Ambiguities on structure analysis of Fe–N thin films

Fe–N thin films with good soft magnetic properties were prepared by RF sputtering and vacuum annealed at 250°C under 12000 A/m magnetic field for 4 h. The structure of α′ in thin films deposited at room temperature is different from α′ formed through the Bain mechanism in bulk samples. In thin films, the lattice parameters of α′ are $\text{c=2.866+1.559}\text{C}{}_{\mathrm{<mtext>N</mtext>}}{}^{\mathrm{<mtext>\alpha </mtext><mtext>\prime </mtext>}}\text{,a=2.864+0.181}\text{C}{}_{\mathrm{<mtext>N</mtext>}}{}^{\mathrm{<mtext>\alpha </mtext><mtext>\prime </mtext>}}$.     

An analysis of the four nuclear quadrupole problem: The microwave spectrum of cyanogen azide

We have derived expressions for the Hamiltonian matrix elements for the coupling of any number of quadrupolar nuclei with the molecular rotation using the Wigner n-j formalism. These expressions have been used to analyse the nuclear quadrupole hyperfine structure of the rotational spectrum of cyanogen azide, NCN₃. The analysis was effected by comparing the experimental high resolution spectral traces with computer simulated traces from which the nuclear quadrupole coupling constants obtained are (MHz)

$\text{x}{}_{\mathrm{aa}}\text{(1) = 4.82 ± 0.02,}\text{x}{}_{\mathrm{bb}}\text{(1) = ?0.70±0.08,}$

$\text{x}{}_{\mathrm{aa}}\text{(2) = ?0.85 ± 0.07,}\text{x}{}_{\mathrm{bb}}\text{(2) = 0.70±0.08,}$

$\text{x}{}_{\mathrm{aa}}\text{(3) = ?0.75 ± 0.07,}\text{x}{}_{\mathrm{bb}}\text{(3) = 0.70±0.05,}$

$\text{x}{}_{\mathrm{aa}}\text{(4) = ?2.27 ± 0.04,}\text{x}{}_{\mathrm{bb}}\text{(4) = 0.70±0.07,}$

Small corrections to the previously reported rotational constants are given.     

Structure and electron density analysis of oxide spinel LiTi2O4

The structure and electron density distribution of the superconducting spinel LiTi₂O₄ have been studied by the maximum entropy method using single crystal X-ray diffraction data at 293 K. The structure refinement confirmed the normal spinel cation distribution, Cubic, Fd-3m, a=8.4067(5) Å, and oxygen parameter u=0.26280(8). From the results of the MEM analysis using 228 independent reflections in the range of $\text{sin}\text{θ/λ<1.3}\text{A}\text{̊}{}^{\mathrm{-1}}\text{,}$ the strong covalent bonding was clearly found between Ti and O atoms, while no bonding was observed around Li atoms. We also calculated the electron density of the cubic spinel LiTi₂O₄ using first principles full-potential linearized augmented-plane-wave method. The electron density obtained experimentally is in good agreement with the theoretical one.