Beryllium-7 Deposition and Its Relation to Sulfate Deposition

Deposition of ⁷Be, a cosmogenic radionuclide, was observed at the Meteorological Research Institute in Tsukuba, Japan from 1986 to 1993 and compared with those of several chemical species observed in Tsukuba over the same period. We found a correlation between the monthly depositions of ⁷ Be and SO ₄ ² -, a major acidic species. The correlation was especially strong for late spring and fall, when both species had high depositional fluxes. This correlation was also observed in precipitation samples collected daily in 1992 at the same site. The cause of this correlation is discussed in connection with the fact that the stratospheric aerosol is composed largely of SO ₄ ² -. ⁷ Be is produced in the upper atmosphere, and detection of ⁷Be, especially in spring and fall in Japan, can be regarded as detection of stratospheric aerosol. However, we conclude that the bulk of the SO ₄ ² - observed did not have a stratospheric or an upper tropospheric origin. The correlation, therefore, may present a new question regarding acidic deposition: Why does the deposition of stratospheric aerosol in Japan coincide with that of nss-SO ₄ ² - originally from anthropogenic sources on the Earth's surface?     

On the Occurrence of Silician Magnetites

Abstract: About 120 specimens of magnetite from various localities are examined by an electron microprobe analyzer. Magnetites containing more than one weight percent of silica but lack of any other components than ferrous and ferric iron, called silician magnetites in the present paper, are recognized in 23 skarn, one vein and one thermally metamorphosed massive sulfide deposits. Thus it is confirmed that this mineral occurs in nature much more frequently than so far expected. Besides silician magnetites, magnetites with appreciable amounts of Al₂O₃, CaO, MgO and other components along with silica, are also recognized in some skarn deposits. Magnetites with such unusual compositions are found only in hydrothermal environments, and it is suggested that precipitation mechanisms seem to be responsible for their formation.
In silician magnetites, excess electric charge brought by the replacement of ferric iron in tetrahedral site by silicon, could be compensated by the replacement of ferric iron in octahedral site by ferrous iron, known as γ–Fe₂SiO₄ component. The natural occurrence of silician magnetites, however, gives no positive support to the existence of this component at crustal pressures. Instead a preliminary Mössbauer experiment demonstrates that one silician magnetite has a maghemite –like structure by the omission of ferrous iron from octahedral site.     

Relationship of Water Chemistry to Serum ThyroidHormones in Captive Sharks with Goitres

Captive whitetip reef sharks, Triaenodon obesus,at Sea Life Park (SLP) Hawaii, Waimanalo, Hawaii develop goitre, whereas, T. obesus at the Waikiki Aquarium (WAQ), Honolulu,Hawaii do not develop goitre. To determine theeffects of natural concentrations of iodine on thereduction of goitre, two sharks from SLP with goitrewere placed in an enclosed coastal lagoon with naturalseawater. Using ultrasound measurements the twogoitres were initially 11.4 cm and 14.6 cm in depthand after 3 months decreased to 4.7 cm and 5.7 cm. Radioimmunoassay analysis of the thyroid hormoneT3 sera concentrations were initially 0.22 ng/mland 0.33 ng/ml and increased to 1.84 ng/ml after beingplaced in the lagoon. Sera T4 were initially0.93 ng/ml and 0.99 ng/ml and increased dramaticallyto 17 ng/ml and 56 ng/ml. Over the six month samplingperiod, two resident sharks in the lagoon with normalthyroids had sera T3 concentrations from 0.89ng/ml to 1.1 ng/ml, and sera T4 concentrationsfrom 3.1 ng/ml to 7.9 ng/ml. The hypothyroidcondition in the SLP goitred-sharks is likely linkedto the low environmental iodide (<0.005 M), andhigh nitrate (111 M) of SLP water. The WAQwell-water facility was characterized by anoxic waterwith high iodide (0.60 M), total iodine (1.90M), and typical nitrate (24.6 M)concentrations of interstitial groundwater. Thedifference of iodide concentration of SLP and WAQ tankwater (<0.005 M versus 0.60 M) wasdirectly related to the hydrogeology of the well-watersources. To avoid goitre in marine aquarium systems,we recommend maintaining iodide concentrations of atleast 0.15 M.     

光波多普勒效应公式的3种推导

给出光波多普勒效应的３种推导,并简述其重要意义。     

Projection of the Future Changes in Tropical Cyclone Activity Affecting East Asia over the Western North Pacific Based on Multi-RegCM4 Simulations

Future changes in tropical cyclone(TC)activity over the western North Pacific(WNP)under the representative concentration pathway RCP4.5 are investigated based on a set of 21 st century climate change simulations over East Asia with the regional climate model RegCM4 driven by five global models.The RegCM4 reproduces the major features of the observed TC activity over the region in the present-day period of 1986-2005,although with the underestimation of the number of TC genesis and intensity.A low number of TCs making landfall over China is also simulated.By the end of the 21st century(2079-98),the annual mean frequency of TC genesis and occurrence is projected to increase over the WNP by16%and 10%,respectively.The increase in frequency of TC occurrence is in good agreement among the simulations,with the largest increase over the ocean surrounding Taiwan Island and to the south of Japan.The TCs tend to be stronger in the future compared to the present-day period of 1986-2005,with a large increase in the frequency of strong TCs.In addition,more TCs landings are projected over most of the China coast,with an increase of~18%over the whole Chinese territory.     

Evaluation of rock excavatability and slope stability along a segment of motorway,Pozanti, Turkey

The Çiftehan-Pozant segment of the Ankara-Pozant motorway is problematic due to the existence of lithological units with variable character. Seven cut slopes are planned along Km 358+000– Km 364+350 of the proposed motorway. The purpose of this study is to determine engineering geological properties of the rocks exposed along the motorway and to assess the excavatability and stability of the cut slopes. Both field and laboratory studies were carried out during this study. Field studies involved geological mapping, detailed discontinuity surveying and sampling. Laboratory tests were carried out to determine unit weight, point load strength index and shear strength parameters of the discontinuities. In the study area, recrystallized limestone, microgabbro, conglomerate and Quaternary deposits are exposed. However, the cut slopes are located within microgabbro and conglomerate. Hard to very hard ripping with local blasting for the fresh inner part of the rocks is recommended for the excavatability. In two cut slopes wedge failure is expected, whereas in another two slopes both wedge and toppling failures are likely to occur. Based on the field observations and stability analyses of the cut slopes, slope flattening with various angles, wire mesh, and drainage ditches are proposed.     

Equation of state,structural behaviour and phase diagram of synthetic MgFe<Subscript>2</Subscript>O<Subscript>4</Subscript>, as a function of pressure and temperature

The behaviour of synthetic Mg-ferrite (MgFe₂O₄) has been investigated at high pressure (in situ high-pressure synchrotron radiation powder diffraction at ESRF) and at high temperature (in situ high-temperature X-ray powder diffraction) conditions. The elastic properties determined by the third-order Birch–Murnaghan equation of state result in K₀=181.5(± 1.3) GPa, K=6.32(± 0.14) and K= –0.0638 GPa^–1. The symmetry-independent coordinate of oxygen does not show significant sensitivity to pressure, and the structure shrinking is mainly attributable to the shortening of the cell edge (homogeneous strain). The lattice parameter thermal expansion is described by _a0+_a1*(T–298)+_a2/(T–298)², where _a0=9.1(1) 10^–6 K^–1, _a1=4.9(2) 10^–9 K^–2 and _a2= 5.1(5) 10^–2 K. The high-temperature cation-ordering reaction which MgFe-spinel undergoes has been interpreted by the ONeill model, whose parameters are = 22.2(± 1.8) kJ mol^–1 and =–17.6(± 1.2) kJ mol^–1. The elastic and thermal properties measured have then been used to model the phase diagram of MgFe₂O₄, which shows that the high-pressure transition from spinel to orthorombic CaMn₂O₄-like structure at T < 1700 K is preceded by a decomposition into MgO and Fe₂O₃.     

Diagenesis and incipient metamorphism in the western fold-and-thrust belt,SW Urals,Russia

In the western fold-and-thrust belt of the southern Urals, the Kübler and Árkai indices determined on shales, slates and phyllites record an increase from lower late diagenetic to epizonal grade from west to east. The metamorphic grade varies strongly within the different tectonic segments, which are separated by major thrusts. The increase of diagenetic and incipient metamorphic grade from the footwall to the hanging wall of all major Upper Palaeozoic thrusts indicates a pre-Permo/Triassic origin. West of the Avzyan thrust zone, the diagenetic to incipient metamorphic grade is related to the Palaeozoic basin development and reached the final grades in Late Carboniferous to Early Permian times. East of the first Avzyan thrust in the Yamantau anticlinorium, the diagenetic to lower greenschist metamorphic grade is possibly of Neoproterozoic origin and might be related to the development of the Neoproterozoic basin at the eastern margin of the East European Craton. The eastern part of the Yamantau anticlinorium was exhumed below 200 °C in the Late Carboniferous or Early Permian. The diagenetic grade of the autochthonous Palaeozoic sedimentary units increases toward the stack of Palaeozoic nappes and might partly be caused by the deformational process due to the emplacement of the Palaeozoic nappes. Within the Timirovo thrust sheet, the decrease of metamorphic grade with stratigraphic age developed prior to the emplacement of the nappes. The upper anchizonal metamorphic grade of the Upper Devonian slates of the Zilair nappe results from the deformation process related to the Lower Carboniferous nappe emplacement.