We have synthesized a novel spin crossover Fe^II -triazole complex Fe (AZ-trz), where AZ-trz denotes 4-phenylazo-N-[1, 2, 4]triazole-4-yl-benzamide. ⁵⁷Fe Mössbauer spectra and magnetic susceptibility measurements of this compound exhibited a gradual spin crossover behavior by thermal change and also a light-induced excited spin state trapping (LIESST) effect. Both UV-visible absorption spectra and IR spectra confirmed the phenomena. The Fe^II high-spin, HS, state was induced by exciting a d-d electronic transition band of the Fe^II low-spin state species. Furthermore, the measurements revealed the lifetime of excited Fe^II HS state to be 1 min.

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In order to investigate variation of concentrations of airborne radionuclides, ²¹⁴Pb, ²¹²Pb, ⁷Be, and ²¹⁰Pb, accompanied with a typical meteorological event, such as passage of cold front, approach of typhoon, and Asian dust (Kosa), highly time-resolved (2-6 hours) measurements of natural radionuclides were performed by ultra low background γ-ray spectrometry. Surface air concentrations of these nuclides showed characteristic temporal changes by each meteorological phenomenon. In addition, variation patterns were found to be obviously different between short-lived ²¹⁴Pb and ²¹²Pb and long-lived ⁷Be and ²¹⁰Pb. One of causes of the difference might be explained by difference of their sources: local for short-lived nuclides and regional for long-lived ones.

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This work deals with ⁹⁹Mo/^99mTc generators produced from titanium ⁹⁹Mo-molybdate, first synthesized and then irradiated. This method avoids the use of special equipment for the synthesis of radioactive material and reduces the process time which usually is at least 7 h. The effect of four parameters of titanium molybdate gel synthesis on the performance of ⁹⁹Mo/^99mTc generators and some physico-chemical properties of these gels were evaluated: gel irradiation, titanium solution concentration, effect of the washing gels, and their drying temperature. The data reveal that: (1) the irradiation of the titanium molybdate gels did not influence significantly the generator performance, (2) the dehydration of titanium molybdate gels, the presence of occluded salt in the gel during drying, and the washing of the gels after drying improved the diffusion of the ^99mTcO₄^- ions and thus the generator performance, and (3) the gels had a three-dimensional structure with cavities which allowed the diffusion of the ^99mTcO₄^- ions inside the gel and were directly connected with the performance of the titanium ⁹⁹Mo-molybdate ⁹⁹Mo/^99mTc generators.

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Temperature-dependent ¹¹⁹Sn Mössbauer spectroscopy has been used to elucidate the root-mean-square-amplitude-of-vibration (rmsav) of the metal atom in Sn (II) phthalocyanin and to examine the (absence of) metal atom motional anisotropy in the temperature range 90<T<190 K.

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A k₀-based internal monostandard instrumental neutron activation analysis (IM-INAA) method was applied for the multielement analysis in uranium bearing samples. Spectral interference correction factors in INAA due to neutron induced fission of uranium for La, Ce, Nd, Zr, Ru, and Mo as well as activation of uranium for Sm and Lu were evaluated using elemental standards. The correction factors were validated by standard addition method in a synthetic sample containing known amount of natuural uranium. For evaluating the accuracy of the IM-INAA method, the low uranium containing SRM 1633a (coal fly ash) obtained from NIST was used. For method validation of analysis of uranium bearing sample, SRM 1633a spiked with uranium (about 0.05%) was analyzed by IM-INAA method. The standardized IM-INAA method was applied to analyze uranium ore samples obtained from Jaduguda and Bhatin mines, Jharkhand, India for multielement content including U, Th, and rare earth elements (REEs). Chondrite normalized REE patterns were plotted for obtaining Ce and Eu anomalies.

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Fluorosis, osteoselerosis, and systemic illness may result when tolerance levels of fluorine intake are exceeded . To avoid these abnormalities, we shall be aware of the mechanisms of their development. For this, quantitative results gathered from different parts of the world are necessary. In this paper, PIGE method is used to determine fluorine concentration in human teeth, collected from different regions of the Algerian Sahara. Both enamel and dentine regions were inspected. The external and internal mappings of the analyzed teeth have shown more variation in the localized fluorine concentration in dentine than in enamel, and the lowest level of fluorine concentration was observed in the frontier crown-root zone. The obtained results reveal relatively high fluorine concentration lying within the limit of fluorosis, according to the standardised grading dental fluorosis.

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The decay rate of ⁷Be electron capture (EC) was measured in C₆₀ and Be metal with a reference method. The halflives of ⁷Be endohedral C₆₀ (⁷Be@C₆₀) and ⁷Be in Be metal (Be metal (⁷Be) ) were found to be 52.65±0.04 and 53.25±0.04 days, respectively. This amounts to a 1.13% difference in the EC-decay half-life between ⁷Be@C₆₀ and Be meta (⁷Be). The result is a reflection of the different electron wave-functions for ⁷Be inside C₆₀ compared to when ⁷Be is in a Be metal. Here, the magnitude of the average charge-transfer from the L (2s) electrons of the ⁷Be atom plays an important role in such variation in the decay constant in the environments.

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This paper presents a simplified time-independent model which calculates radioactivities of short-lived radon daughters in rainwater as a function of rainfall rate for unit concentration of radon in cloud. The model incorporates processes of impact collection for cloud droplets by raindrops, removal of raindrops from cloud and transport time of raindrops from the cloud base to the ground as forms of semi-empirical formulas. Radon concentrations in rain clouds are estimated from comparisons between model calculations and ground-level observations made over a few years.

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