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51.
Blooms of cyanobacteria are responsible for many problems in freshwater ecosystems. The massive growth of these microorganisms may limit the utilization of freshwater for human requirements since, apart from other problems, the production of toxic substances has been found to occur frequently during blooming periods. Ecologically, cyanobacterial blooms can modify dramatically the ecosystem through their low edibility within the food web and the huge primary production. Thus, saprobic processes are stimulated and the characteristics related to anaerobic conditions are also more extreme.Cyanobacterial blooms are many times explained as the consequence of the eutrophication of waterbodies. However, factors promoting bloom formation and ecological succession of cyanobacteria are not well understood yet. 相似文献
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Tsuyoshi Samukawa Masamitsu Onitsuka Kazuyuki Ohta Mamoru Tominaga Hidenori Yoshiyama 《Journal of Oceanography》1992,48(2):129-138
In the marine environment, colloidal sulfurs often occur due to the redox reaction of sulfide ions and oxygen molecules. It is important to know the spectral refractive index of colloidal sulfurs for the discussion of the light scattering in the region where colloidal sulfurs are formed. We presented new methods to estimate the refractive index from the wave length of maximum absorbance (turbidity) of a nearly mono-dispersed colloidal solution. In these methods, the ripples in a first main maximum of the scattering efficiency,Q
sca
, were taken into consideration. By virtue of these methods, we obtained the spectral refractive index of colloidal sulfurs,m
s
(), at 20°C. The Cauchy's expression of it was given by
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相似文献
55.
Ikkoh Funaki Hidenori Kojima Hiroshi Yamakawa Yoshinori Nakayama Yukio Shimizu 《Astrophysics and Space Science》2007,307(1-3):63-68
To propel a spacecraft in the direction leaving the Sun, a magnetic sail (MagSail) blocks the hypersonic solar wind plasma
flow by an artificial magnetic field. In order to simulate the interaction between the solar wind and the artificially deployed
magnetic field produced around a magnetic sail spacecraft, a laboratory simulator was designed and constructed inside a space
chamber. As a solar wind simulator, a high-power magnetoplasmadynamic arcjet is operated in a quasisteady mode of 0.8 ms duration.
It can generate a simulated solar wind that is a high-speed (above 20 km/s), high-density (1018 m−3) hydrogen plasma plume of ∼0.7 m in diameter. A small coil (2 cm in diameter), which is to simulate a magnetic sail spacecraft
and can obtain 1.9-T magnetic field strength at its center, was immersed inside the simulated solar wind. Using these devices,
the formation of a magnetic cavity (∼8 cm in radius) was observed around the coil, which indicates successful simulation of
the plasma flow of a MagSail in the laboratory. 相似文献
56.
Yusaku Takubo Hidenori Terasaki Tadashi Kondo Shingo Mitai Seiji Kamada Takumi Kikegawa Akihiko Machida 《Comptes Rendus Geoscience》2019,351(2-3):182-189
A technique for density measurement under high pressure and high temperature was developed using the X-ray absorption imaging method combined with an externally heated diamond anvil cell. The densities of solid and liquid In were measured in the pressure and temperature ranges of 3.2–18.6 GPa and 294–719 K. The densities obtained through the X-ray absorption imaging method were in good agreement (less than 2.0% difference) with those obtained through X-ray diffraction. Based on the measured density, the isothermal bulk modulus of solid In is determined as 48.0 ± 1.1?40.9 ± 0.8 GPa at 500 K, assuming K′ = 4 to 6. The compression curve of liquid In approaches that of solid In at higher pressures and does not cross over the solid compression curve in the measurement range. The present technique enables us to determine the densities of both solids and liquids precisely in a wide pressure and temperature range. 相似文献
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Santa Man Shrestha Hideji Kawakami Eric Augustus Tingatinga Hidenori Mogi 《地震工程与工程振动(英文版)》2010,9(4):481-491
A new method for wave propagation modeling is introduced in this paper. By using the constraint optimization (Lagrange multiplier) method, the sum of weighted squared Fourier amplitudes is minimized when subjected to a constraint. The sum of the maximum amplitudes obtained from all output models is normalized to unity and is taken as a constraint. In this method, all the actual time histories are considered as outputs and dealt with equally. Independently of the combinations of time histories (or the first ... 相似文献
58.
A method has been developed for estimating the filtered narrow band surface albedo with Landsat/TM data. In this method, the surface albedo from filtered range of Landsat/TM is converted to the surface albedo with unfiltered spectral range. The atmospheric effects on each channel are systematically different, because of the different spectral behavior of atmospheric parameters. As a result, in this study, atmospheric correction has been done respectively in different parameters for visible and infrared channels. The surface albedos of the Kushiro Mire gotten with this method were compared with the observed data there. The results show that the satellite inferred albedos have a good agreement to the diurnal mean of ground observed albedos with 3% systematic error. There is a seasonal variation of albedo in high and low mires, the albedo decreased gradually from April to July and reached its minimum in July, further it rose gradually from August to October. It is also clear that there is a characteristic pattern of surface distribution according to the vegetation types of this area. The average surface albedos of each type of community are 0.164 for Sphagnum, 0.175 for Carex, 0.179 for Pragmites and 0.166 for Alnus. In the other words, the albedo in high mire (mainly covered by Sphagnum) is lower than that in low mire (mainly covered by Phragmites and Carex). 相似文献
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Akio Suzuki Eiji Ohtani Hidenori Terasaki Ken-ichi Funakoshi 《Physics and Chemistry of Minerals》2005,32(2):140-145
In situ X-ray viscometry of the silicate melts was carried out at high pressure and at high temperature. The viscosity of the silicate melts in the diopside(Di)–jadeite(Jd) system was determined in the pressure range from 1.88 GPa to 7.9 GPa and in the temperature range from 2,003 K to 2,173 K. The viscosity of the Di 25%–Jd 75% melt decreases continuously to 5.0 GPa, whereas the viscosity of the Di 50%–Jd 50% melt increases over 3.5 GPa. The viscosity of the Di50%–Jd 50% melt reaches a minimum around 3.5 GPa. Since the amounts of silicon in the two melts are the same, the difference in the pressure dependence of the viscosity may be controlled by another network-forming element, i.e., aluminum. The difference in the pressure dependence of the viscosities in the melts with two intermediate compositions in the Di–Jd system is estimated to be due to the difference in the melt structures at high pressures and high temperatures. 相似文献
60.
Takeshi Sakai Eiji Ohtani Hidenori Terasaki Masaaki Miyahara Masahiko Nishijima Naohisa Hirao Yasuo Ohishi Nagayoshi Sata 《Physics and Chemistry of Minerals》2010,37(7):487-496
Fe–Mg partitioning between post-perovskite and ferropericlase has been studied using a laser-heated diamond anvil cell at
pressures up to 154 GPa and 2,010 K which corresponds to the conditions in the lowermost mantle. The composition of the phases
in the recovered samples was determined using analytical transmission electron microscopy. Our results reveal that the Fe–Mg
partition coefficient between post-perovskite and ferropericlase (K
DPPv/Fp) increases with decreasing bulk iron content. The compositional dependence of K
DPPv/Fp on the bulk iron content explains the inconsistency in previous studies, and the effect of the bulk iron content is the most
dominant factor compared to other factors, such as temperature and aluminum content. Iron prefers ferropericlase compared
to post-perovskite over a wide compositional range, whereas the iron content of post-perovskite (X
FePPv, the mole fraction) does not exceed a value of 0.10. The iron-rich ferropericlase phase may have significant influence on
the physical properties, such as the seismic velocity and electrical conductivity at the core–mantle boundary region. 相似文献
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