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111.
Trace elements in land plants: Concentration ranges and accumulators of rare earths,Ba, Ra,Mn, Fe,Co and heavy halogens 总被引:2,自引:0,他引:2
M. Koyama M. Shirakawa J. Takada Y. Katayama T. Matsubara 《Journal of Radioanalytical and Nuclear Chemistry》1987,112(2):489-506
More than 2000 samales of land plant leaves, mostly of tree, have been analyzed by neutron activation analysis in order to find out macroscopic relations between distributions of chemical elements in plants and soil characteristics. The distributions of the elements in plants were also examined from the view point of botanical taxonomy or phylogeny. New species which accumulate Co, rare earths, Ba, Ra, heavy halogens and some other elements have been found. Capability or potentiality for accumulating elements could be related to higher ranks of taxonomy, that is, genus or family. The nature of soil is also found to have profound effects on the extent of accumulation of elements in plants. 相似文献
112.
Kenji Mizoguchi Kiyoshi Kume Hideki Shirakawa 《Molecular Crystals and Liquid Crystals》2013,570(1):459-462
We measured a frequency dependence of ESR line width in (CH)x and (CD)x at frequencies 5~9,500 MHz. From a detailed analysis we could independently deduce 1-D diffusion rate of electron spin (neutral soliton) D‖ /c‖ 2, and the trapped spin concentration C between 200 and 340 K. 相似文献
113.
Dr. Takahito Watanabe Yumi Kasai Prof. Dr. Hiromi Tobita 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(59):13491-13495
Reaction of N-heterocyclic carbene (NHC)-stabilized PGeP-type germylene Ge{o-(PiPr2)C6H4}2⋅MeIiPr ( 1 ) (MeIiPr=1,3-diisopropyl-4,5-dimethylimidazol-2-ylidene) with Ni(cod)2 gave pincer germylene complex Ni[Ge{o-(PiPr2)C6H4}2](MeIiPr) ( 2 ), in which the Ge center of 2 is significantly pyramidalized. Theoretical calculation on 2 predicted the ambiphilicity of the germanium center, which was confirmed by reactivity studies. Thus, complex 2 reacted with both Lewis base MeIMe (MeIMe=1,3,4,5-tetramethylimidazol-2-ylidene) and Lewis acid BH3⋅SMe2 at the germanium center to afford the adducts Ni[Ge{o-(PiPr2)C6H4}2⋅MeIMe](MeIiPr) ( 3 ) and Ni[Ge{o-(PiPr2)C6H4}2⋅BH3](MeIiPr) ( 4 ), respectively. Furthermore, the former was slowly converted to dinuclear complex Ni2[Ge{o-(PiPr2)C6H4}2]2(MeIMe)2 ( 5 ) at room temperature. Complex 5 can be regarded as a dimer of the MeIMe analog of 2 with a Ni-Ge-Ge-Ni linkage. 相似文献
114.
115.
Yuji Sasaki Yumi Sugo Yoshihiro Kitatsuji Akira Kirishima Takaumi Kimura Gregory R Choppin 《Analytical sciences》2007,23(6):727-731
Water-soluble ligands, N,N,N',N'-tetramethyldiglycolamide (TMDGA), N,N,N',N'-tetraethyldiglycolamide (TEDGA), N,N,N',N'-tetrapropyldiglycolamide (TPDGA) and N,N-dipropyldiglycolamic acid (DPDGAc) were prepared and their abilities to complex with and to back-extract the metal cations were investigated. These results indicate that the DGA series and DPDGAc have a stronger complexing ability with Am(III) and Pu(IV) than comparable carboxylic and aminopolycarboxylic acids. Among these ligands, the trend of the strength of their complexing ability is TPDGA approximately TEDGA > TMDGA approximately DPDGAc. TPDGA has significant loss to the extraction solvent due to its high hydrophobicity. It is evident from the present work that TEDGA is the best reagent for the reverse-extraction of not only An(III), (IV) but also Ca(II), Sc(III), Y(III), Zr(IV), La(III), Hf(IV), and Bi(III). 相似文献
116.
117.
A new mathematical model for finding the optimal harvesting policy of an inland fishery resource under incomplete information is proposed in this paper. The model is based on a stochastic control formalism in a regime‐switching environment. The incompleteness of information is due to uncertainties involved in the body growth rate of the fishery resource: a key biological parameter. Finding the most cost‐effective harvesting policy of the fishery resource ultimately reduces to solving a terminal and boundary value problem of a Hamilton‐Jacobi‐Bellman equation: a nonlinear and degenerate parabolic partial differential equation. A simple finite difference scheme for solving the equation is then presented, which turns out to be convergent and generates numerical solutions that comply with certain theoretical upper and lower bounds. The model is finally applied to the management of Plecoglossus altivelis, a major inland fishery resource in Japan. The regime switching in this case is due to the temporal dynamics of benthic algae, the main food of the fish. Model parameter values are identified from field measurement results in 2017. Our computational results clearly show the dependence of the optimal harvesting policy on the river environmental and biological conditions. The proposed model would serve as a mathematical tool for fishery resource management under uncertainties. 相似文献
118.
Prof. Dr. Takanori Iwasaki Shin Murakami Prof. Dr. Youhei Takeda Prof. Dr. Gaku Fukuhara Prof. Dr. Norimitsu Tohnai Prof. Dr. Yumi Yakiyama Prof. Dr. Hidehiro Sakurai Prof. Dr. Nobuaki Kambe 《Chemistry (Weinheim an der Bergstrasse, Germany)》2019,25(65):14817-14825
The relationship between the photophysical properties and molecular orientation of 1,3,6,8-tetraalkylpyrenes in the solid state is described herein. The introduction of alkyl groups with different chain structures (in terms of length and branching) did not affect the photophysical properties in solution, but significantly shifted the emission wavelengths and fluorescence quantum yields in the solid state for some samples. Pyrenes bearing ethyl, isobutyl, or neopentyl groups at the 1-, 3-, 6-, and 8-positions showed similar emission profiles in both the solution and solid states. In contrast, pyrenes bearing other alkyl groups exhibited an excimer emission in the solid state, similar to that of the parent pyrene. On studying the photophysical properties in the solid state with respect to the obtained crystal structures, the observed solid-state photophysical properties were found to depend on the relative position of the pyrene chromophores. The solid-state photophysical properties can be controlled by the alkyl groups, which provide changing crystal packing. Among the pyrenes tested, 1,3,6,8-tetraethylpyrene showed the highest fluorescence quantum yield of 0.88 in the solid state. 相似文献
119.
Palchunova Kseniya Mino Toshihiro Mihashi Toshifumi Liu Jonathan Tasaki Kuniharu Hasegawa Yumi Hiraoka Takahiro Oshika Tetsuro 《Optical Review》2022,29(3):188-196
Optical Review - To evaluate the repeatability of the optical coherence tomography (OCT) retinal shape measurement with and without alignment correction in children and adults. 62 eyes of the 31... 相似文献
120.