Papers by Satoru Nakashima
Geophysical Journal International, 2017
Bookmarks Related papers MentionsView impact
Journal of remote sensing, 2003
RGB values from CCD cameras are device-dependent, and are not able to be simply converted into in... more RGB values from CCD cameras are device-dependent, and are not able to be simply converted into international color standard CIE XYZ (and L*a*b*) values. We have developed a calibration method from these RGB values to CIE L*a*b* values by using a standard color sample set. We achieved the accuracy of ƒ¢E*ab 2.23 (standard deviation of error•~2.5) by applying a couple of calculation techniques to the calibration. First, accuracies of X, Y and Z estimations in the lower range are enhanced, while those in the higher are diminished. In the converting equations from XYZ to L*a*b*, XYZ values are powered by third. Hence, estimation error in low XYZ region reduces L*a*b* estimation accuracy more effectively. The second method is interactive modifications of X and Z values. Values of a* and b* is derived by Y and X, and Y and Z, respectively. For example, a combination of larger estimation error in Y and smaller estimation error of Z yields very high deviation of b*. To avoid this, we modifi...
Bookmarks Related papers MentionsView impact
Journal of the Mineralogical Society of Japan, 1990
Bookmarks Related papers MentionsView impact
Origins of Life and Evolution of Biospheres, 2016
Bookmarks Related papers MentionsView impact
生物物理, Aug 15, 2010
Bookmarks Related papers MentionsView impact
We have proposed a novel astrobiological mission "Tanpopo" on the International Space S... more We have proposed a novel astrobiological mission "Tanpopo" on the International Space Station. The mission has six sub-themes. In the present paper, we will present scientific objectives of two sub-themes: (1) Capture of cosmic dusts to analyze organic compounds of extraterrestrial origins, and (2) Exposure of organic compounds in actual space environments. Organic compounds found in such extraterrestrial bodies as comets and meteorites seem to have been originally formed in dense clouds before formation of the solar system. When frozen mixtures of simple molecules found in ice mantles of interstellar dusts with high-energy particles from accelerators, complex organic compounds with molecular weights of thousands were formed. They gave amino acids after acid-hydrolysis. It strongly suggested that complex organic compounds containing precursor of bioorganic compounds were formed in interstellar environments and that they were incorporated in such solar system small bodies a...
Bookmarks Related papers MentionsView impact
Astrobiology" is a novel interdisciplinary field defined as origins, evolution, distribution... more Astrobiology" is a novel interdisciplinary field defined as origins, evolution, distribution and destiny of life in the Earth and elsewhere in space. We organized the working group "Astrobiology Experiments in Earth Orbit" and have been discussed possible subjects of astrobiological experiments in Earth orbit since 2004. In 2006, we picked up one of the subjects, and it was proposed to JAXA as the "Tanpopo mission". In order to study origins and distribution of life in space, both in earth orbit and in planetary bodies, it is necessary to develop novel sensitive techniques to detect and characterize organic compounds and microorganisms. In this year, we discussed such instrumental analytical techniques as mass spectrometry and soft X-ray spectroscopy. One of the promising techniques to detect extant life is fluorometric
Bookmarks Related papers MentionsView impact
Astrobiology" is defined as origins, evolution, distribution and destiny of life in the Eart... more Astrobiology" is defined as origins, evolution, distribution and destiny of life in the Earth and elsewhere in space, which was first proposed by NASA in late 1990s. We organized the working group "Astrobiology Experiments in Earth Orbit" and have been discussed possible subjects of astrobiological experiments in Earth orbit. In 2006, we picked up one of the subjects, and it was proposed to JAXA as the "Tanpopo mission". In this year, we discussed the remaining problems around the Tanpopo mission, together with other possible subjects. In order to analyze organic compounds and microbes, we should have novel most sensitive techniques in the world. One of the promising techniques to detect extant life is fluorometric microscopy. In order to detect quite trace level of organics in dusts, mass microscopy techniques such as TOF-SIMS. These techniques can be used not only in the Tanpopo mission but also future missions to detect life on Mars and beyond. One of the...
Bookmarks Related papers MentionsView impact
MRS Proceedings, 1991
ABSTRACTThe chemical forms of iron minerals and uranyl species have been examined non-destructive... more ABSTRACTThe chemical forms of iron minerals and uranyl species have been examined non-destructively by visible microspectroscopy and electron microprobe analysis in order to obtain a better understanding of uranium redistribution and fixation mechanisms. The uranyl species are associated with sub-micron sized iron minerals, such as hematite (Fe2O3), goethite (FeOOH), and ferrihydrite (Fe4-5(OH,O)12). Additionally, some uranium is fixed to goethite in weathered chlorite grains. Sub-micron sized saleeite, Mg(UO2)2(PO4)2. 1OH2O, is the most probable uranyl phase associated with the iron minerals. This suggests that the uranium fixation in the vicinity of the Koongarra uranium ore deposits is the result of the coprecipitation and sorption of microcrystals of saleeite on to the iron minerals released during weathering of chlorite.
Bookmarks Related papers MentionsView impact
Kinetic heating experiments of organic material in the Tagish Lake chondrite were conducted in-si... more Kinetic heating experiments of organic material in the Tagish Lake chondrite were conducted in-situ under a micro FTIR. Two types of aliphatic C-H groups were revealed, one thermally fragile and the other being significantly more refractory.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Marine Geology, 1992
Bookmarks Related papers MentionsView impact
Researches in organic geochemistry, 1992
Bookmarks Related papers MentionsView impact
Plants, 2020
Leaf water storage is a complex interaction between live tissue properties (anatomy and physiolog... more Leaf water storage is a complex interaction between live tissue properties (anatomy and physiology) and physicochemical properties of biomolecules and water. How leaves adsorb water molecules based on interactions between biomolecules and water, including hydrogen bonding, challenges our understanding of hydraulic acclimation in tall trees where leaves are exposed to more water stress. Here, we used infrared (IR) microspectroscopy with changing relative humidity (RH) on leaves of tall Cryptomeria japonica trees. OH band areas correlating with water content were larger for treetop (52 m) than for lower-crown (19 m) leaves, regardless of relative humidity (RH). This high water adsorption in treetop leaves was not explained by polysaccharides such as Ca-bridged pectin, but could be attributed to the greater cross-sectional area of the transfusion tissue. In both treetop and lower-crown leaves, the band areas of long (free water: around 3550 cm−1) and short (bound water: around 3200 cm−...
Bookmarks Related papers MentionsView impact
THE REVIEW OF HIGH PRESSURE SCIENCE AND TECHNOLOGY, 1998
Bookmarks Related papers MentionsView impact
Tree Physiology, 2017
Bookmarks Related papers MentionsView impact
Journal of Taphonomy, 2006
In order to evaluate alteration of calcareous nannoplankton assemblages during their deposition-d... more In order to evaluate alteration of calcareous nannoplankton assemblages during their deposition-diagenesis, a dissolution experiment of calcareous nannoplankton from a marine sediment sample was carried out. An assemblage of calcareous nannoplankton (coccoliths) found in surface sediments taken from the Caribbean Sea was put in stirred pure water with a fixed ionic strength (0.7 mol/l KCl) at 27.5°C to trace their dissolution behaviors. Temporal changes in pH and Ca concentration during the dissolution experiment indicated that the dissolution kinetics were similar to those found in the simple calcite system. By counting numbers of different species and taxonomic groups, the apparent dissolution rates were determined for each species and taxonomic group. The obtained individual dissolution rates differ among different species and taxonomic groups up to a factor of about 9. The resulted nannoplankton assemblages after dissolution were therefore very different from the original ones. This implies that the fossil assemblage can be altered during the deposition-diagenesis by carbonate dissolution processes.
Bookmarks Related papers MentionsView impact
Viva Origino, Mar 1, 1998
Bookmarks Related papers MentionsView impact
Agu Fall Meeting Abstracts, Dec 1, 2002
Bookmarks Related papers MentionsView impact
ChemInform, 2006
Bookmarks Related papers MentionsView impact
Uploads
Papers by Satoru Nakashima