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991.
Development of porosity in carbons from yeast grains by activation with alkali metal carbonates 总被引:1,自引:0,他引:1
Cellular structured activated carbon samples were prepared with the aid of alkali carbonates X2CO3 (X = Li, Na, K, Rb, or Cs) from dry bread yeast with a milling procedure. The resultant carbon possesses a very large adsorption amount even for supercritical methane. The activation with Cs2CO3 gave the greatest surface area of 2420 m2 g(-1) from the subtracting pore effect method. The activation efficiency of X2CO3 (X = Li, Na, K, Rb, and Cs) was associated with the order of Gibbs free energy of X2O (X = Li, Na, K, Rb, and Cs) which should play an important role in the gasification. The carbon activated with Rb2CO3 gave the greatest adsorption amount of supercritical methane of 90 mg g(-1) at 0.9 MPa at 303 K. 相似文献
992.
Hajime Seito Tatsuya Ichikawa Hiroaki Hanaya Yoshishige Sato Hirohisa Kaneko Yasuyuki Haruyama Hiroshi Watanabe Takuji Kojima 《Radiation Physics and Chemistry》2009,78(11):961-965
Characteristics of clear PMMA dosimeter (Radix W) were studied for electron irradiation and compared with the response for gamma irradiation. The dose–response curves were nearly linear up to 30 kGy and become sublinear at higher doses. The radiation-induced absorbance was reduced with 6% within 4 h after irradiation. Dose comparisons were performed for 2, 3, 4 and 5 MeV electron irradiation using cellulose triacetate dosimeter (CTA) (FTR-125) and Radix W dosimeters which were independently calibrated for 2 MeV electrons and 60Co gamma-rays using calorimeter and ionizing chamber, respectively. The doses estimated by CTA and Radix W were different by about 20%. The magnitude of this difference was, however, independent of electron energy. 相似文献
993.
Fumio Hamada Miyuki Narita Akira Makabe Hideaki Itoh 《Journal of inclusion phenomena and macrocyclic chemistry》2001,40(1-2):83-88
The effect of dansyl modified -cyclodextrin (1)on the chaperone activity of heat shock proteins such as HSP70 and HSP90 hasbeen studied. The fluorescence intensity of 1 was decreased when HSP70 and HSP90 were added to the host solution. This phenomenon suggested that host–guest complexation was occuring. The binding constants of 1 were obtained using a 1:1 complex formation type equation by employing the guest-induced fluorescence variations. Host 1 exhibited a higher binding ability forHSP70 than for HSP90. The effects of 1 on the chaperone activity and degradation of HSP70 and HSP90 were studied by measuring the absorption of aggregation of citrate synthase (C.S.) and sodium dodecyl sulfate (SDS)polyacrylamide gel electrophoresis of trypsin degradation, respectively. Host1 can contribute to regulate C.S. aggregation andpromote trypsin degradation of HSP70 and HSP90. 相似文献
994.
An enantio- and diastereoselective stepwise cyclization of polyprenoids induced by Lewis acid-assisted chiral Br?nsted acids (chiral LBAs) and achiral LBAs is described. In particular, the absolute stereocontrol in the initial cyclization of polyprenoids to form an A-ring induced by chiral LBAs and the importance of the nucleophilicity of the internal terminator in polyprenoids for the relative stereocontrol in subsequent cyclization are demonstrated. (-)-Ambrox was synthesized via the enantioselective cyclization of (E,E)-homofarnesyl triethylsilyl ether with tin(IV) chloride-coordinated (R)-2-(o-fluorobenzyloxy)-2'-hydroxy-1,1'-binaphthyl ((R)-BINOL-o-FBn) and subsequent diastereoselective cyclization with CF(3)CO(2)H.SnCl(4) as key steps. Protection of (E,E)-homofarnesol by a triethylsilyl group increased the enantioselectivity of chiral LBA-induced cyclization and both the chemical yield and diastereoselectivity in the subsequent cyclization. The enantioselective cyclization of homo(polyprenyl)arenes possessing an aryl group was also induced by (R)-BINOL-o-FBn.SnCl(4). Several optically active podocarpa-8,11,13-triene diterpenoids and (-)-tetracyclic polyprenoid of sedimentary origin were synthesized (75-80% ee) by the enantioselective cyclization of homo(polyprenyl)benzene derivatives induced by (R)-BINOL-o-FBn.SnCl(4) and subsequent diastereoselective cyclization induced by BF(3).Et(2)O/EtNO(2) or CF(3)CO(2)H .SnCl(4). 相似文献
995.
Adsorption of polyaromatic hydrocarbons on single wall carbon nanotubes of different functionalities and diameters 总被引:2,自引:0,他引:2
Gotovac S Yang CM Hattori Y Takahashi K Kanoh H Kaneko K 《Journal of colloid and interface science》2007,314(1):18-24
Adsorption from toluene solution of phenanthrene and tetracene on single wall carbon nanotubes (SWCNT) is measured. Comparison of adsorbents such as laser ablation and HipCO samples reveals multiple factors influencing the adsorption mechanism. Acid functionalized carbon nanotubes have shown markedly increased adsorbability for the polyaromatic molecules. The linear tetracene molecule's adsorption is more promoted on nanotubes with increasing diameter, but also additionally with presence of the carboxylic groups. The adsorption mechanisms on carboxylic sites and on the bold, non-functionalized large-diameter nanotubes are suggested and supported by detailed characterization of the SWCNTs applied. 相似文献
996.
T. Ishii S. Shigematsu H. Makii M. Asai K. Tsukada A. Toyoshima M. Matsuda A. Makishima T. Shizuma J. Kaneko I. Hossain H. Toume M. Ohara S. Ichikawa T. Kohno M. Ogawa 《Physics of Atomic Nuclei》2007,70(8):1457-1461
We have measured deexcitation γ rays in the neutron-rich nuclei of 240U, 246Pu, and 250Cm produced by the (18O, 16O) two-neutron transfer reactions, in coincidence with the 16O particles using Si ΔE−E detectors. The γ rays in these nuclei were identified by selecting the kinetic energies of 16O particles, which correspond to the excitation energies in the residual nuclei below the neutron separation energies. The
ground-state bands of 240U, 246Pu, and 250Cm were established up to 12+ states and the K
π = 0− octupole band of 240U was established up to 9− states. The systematics of the moments of inertia of the ground-state bands for actinide nuclei shows that the deformed subshell
closure at N = 152 is sustained for 96Cm isotopes and that it disappears for 94Pu isotopes.
The text was submitted by the authors in English. 相似文献
997.
Inoue R Muranaga K Takayanagi H Hanamura E Jo M Akazaki T Suemune I 《Physical review letters》2011,106(15):157002
Transport properties of a superconductor-semiconductor-superconductor (Su-Sm-Su) junction with superlattice structure are investigated. Differential resistance as a function of voltage shows oscillatory behavior under the irradiation of radio-frequency (rf) waves with the specific frequency of 1.77 GHz regardless of the superconducting materials and the junction geometries. Experimental data are quantitatively explained in terms of the coupling of superconducting quasiparticles with long-wavelength acoustic phonons indirectly excited by the rf waves. We propose that the strong coupling causes the formation of novel composite particles, Andreev polarons. 相似文献
998.
Nakano M Kishi R Ohta S Takahashi H Kubo T Kamada K Ohta K Botek E Champagne B 《Physical review letters》2007,99(3):033001
Although most third-order nonlinear optical (NLO) materials are closed-shell singlet systems, this Letter theoretically shows that the third-order NLO properties are drastically enhanced in symmetric open-shell diradical systems with intermediate diradical character and further reveals that this enhancement is associated with the ferromagnetic and antiferromagnetic interactions. This new paradigm opens up a promising area for designing new third-order NLO materials. 相似文献
999.
1000.
Hideaki Matsunaga Chikako Hajiri 《Journal of Mathematical Analysis and Applications》2010,369(2):616-622
This paper is devoted to the stability analysis of a delay difference system of the form xn+1=axn−k+byn, yn+1=cxn+ayn−k, where a, b and c are real numbers and k is a positive integer. We establish some exact conditions for the zero solution of the system to be asymptotically stable. 相似文献