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排序方式: 共有1100条查询结果,搜索用时 15 毫秒
1.
Yuichi Kamiya 《Acta Mathematica Hungarica》2004,105(1-2):103-114
A. Beurling introduced harmonic functions attached to measurable functions satisfying suitable conditions and defined their spectral sets. The concept of spectral sets is closely related to approximations by trigonometric polynomials. In this paper we consider spectral sets of the harmonic functions attached to the Riemann zeta-function and its modification. 相似文献
2.
Crosslinked poly(N-isopropylacrylamide) gel was tested on the feasibility for a preparative electrophoretic matrix. Horse heart myoglobin and bovine hemoglobin were well separated on the gel matrix electrophoretically by molecular sieving effect of the gel network. Relative mobilities of those proteins in the gel were larger than those in a crosslinked polyacrylamide gel of the same polymer concentration. After the separation, the protein-containing portion of the gel underwent swelling at 4°C and deswelling at 37°C, alternatively. As a result of the deswelling, each protein was recovered in a discharged solution out of the gel at almost 100% yield. 相似文献
3.
In this study, we attempted to control the timing of light-emission from bioluminescent bacteria, by changed cell numbers inoculated into medium. Luminous bacteria express bioluminescence when the number of cells reached a threshold. Inoculated cell density had an effect on the time of bioluminescence starting. Samples were prepared by varying cell density of inoculation. In the results, all the vials showed different luminescence profiles in the order of inoculated cell population. 相似文献
4.
5.
A poly(N-isopropylacrylamide) (PNIPAAm)-like biodegradable thermosensitive polydepsipeptide, poly[Glc-Asn(N-isopropyl)], was synthesized by introducing an isopropyl amide group into poly[Glc-Asn]. Poly[Glc-Asn(N-isopropyl)] was degraded in vitro by cleavage of the ester bonds in the main chain in water at room temperature. The non-toxic nature of the polymer and its degradation products, coupled with a cloud point at 29 degrees C in water, make this polymer attractive for biomedical implant applications. 相似文献
6.
Toshio Masuoka H. Yasuda 《Journal of polymer science. Part A, Polymer chemistry》1981,19(11):2937-2946
Plasma polylmerization occurs in plasmas surrounded by surfaces and polymer formation is one of the complicated interactions that take place between active species and molecules which constitute surfaces and gas phases. Effects of reactor wall, substrate materials, flow rate, and discharge power on polymer formation, and properties of polymer deposits were investigated by ESCA, IR (infrared) spectroscopy, and the measurement of system pressure. The effect of surface is important at the initial stage of plasma polymerization which can be easily detected by the system pressure change; however, integrated properties such as IR spectroscopy and the deposition rate show the effect in a less pronounced manner. ESCA, which reflects the properties of surface (approximately 20 A? in depth), showed the effect of surface in an even less sensitive manner. The amount and properties (including the effects of surfaces) are dependent on plasma polymerization parameter W/FM(W, wattage; F, volume flow rate; and M, molecualar weight of monomer) and the location of deposition within a reactor. IR and ESCA data clearly showed the dependence of polymer properties on W/FM; i.e., increase of W and decrease of M to be equivalent. When all these factors were kept under control, the reproducibility of plasma polymerization was found to be excellent. 相似文献
7.
Keiichiro Fukumoto Masatoshi Chihiro Yuichi Shiratori Masataka Ihara Tetsuji Kametani Toshio Honda 《Tetrahedron letters》1982,23(29):2973-2976
Thermolysis of a benzocyclobutene derivative () prepared from norcamphor produced stereoselectively a tetracyclic compound (), which was converted to a lactone () having correct stereochemistry at C7, C8, C9, C11, C13, and C14 positions of (±)-klaineanone. 相似文献
8.
This work reports the principle, advantage, and limitations of analytical photoion spectroscopy which has been applied to dissociative photoionization processes for diatomic molecules such as H2, N2, CO, and NO. Characteristic features observed in the differential photoion spectra are summarized with a focus on (pre)dissociation of(i) multielectron excitation states commonly observed in the inner valence regions,(ii) shape resonances, and(iii) doubly charged parent ions. Possible origins for negative peaks in the differential spectra are discussed. This spectroscopy is applied to the reported photoion branching ratios for D2 (and H2 at high energies). The main findings are as follows: (1) The direct dissociation of theX 2Σ g + (1sσ g ) state of D 2 + , the two-electron excited state1Σ u + (2pσ u 2sσ g ) of D2, and the2Σ u + (2pσ u ) state of D 2 + appear clearly in the differential spectrum, as previously observed for H2. (2) Decay of H 2 + (D 2 + ) to H+ (D+) above 38 eV is due to the direct dissociation of highly excited states of H 2 + (D 2 + ) such as the2Σ g + (2sσ g ) and high-lying Rydberg states converging on H 2 2+ (D 2 2+ ). (3) In the ionization continuum of H 2 2+ (D 2 2+ ) peculiar dissociation pathways are observed. The differential photoion spectra for O2 derived from the reported photoion branching ratios are also presented. The (pre)dissociation of theb 4Σ g ? ,B 2Σ g ? , III2Π u ,2Σ u ? , and2,4Σ g ? states of O 2 + appears as the corresponding positive values in the spectra in accord with previous observations. Some other dissociation pathways possibly contributing to the spectra are discussed including dissociative double ionization. 相似文献
9.
Keivan Esfarjani Yuichi Hashi Satoshi Itoh Sigeo Ihara Yoshiyuki Kawazoe 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1997,41(1):73-76
To study the thermodynamic and mechanical stability of toroidal isomers of C 240, we use a semi-empirical tight-binding theory and calculate their electronic structure, cohesive energy and vibrational spectra within the harmonic approximation. From these, we deduce their free energy at temperatures up to 1500K. The results are also compared to the isomer with icosahedral symmetry. Finally, we discuss within this approach, their stability and abundance. 相似文献
10.
Shimazaki Y Tashiro M Motoyama T Iwatsuki S Yajima T Nakabayashi Y Naruta Y Yamauchi O 《Inorganic chemistry》2005,44(17):6044-6051
Synthetic, structural, spectroscopic, and kinetic studies have been carried out on the Pd(II) complexes of new 2N1O-donor ligands containing a pendent indole, 3-(N-2-pyridylmethyl-N-2-hydroxy-5-methoxybenzylamino)ethylindole (HMeO-iepp), 3-(N-2-pyridylmethyl-N-2-hydroxy-5-nitrobenzylamino)ethylindole (HNO2-iepp), and (N-2-pyridylmethyl-3-indolylethylamino)acetic acid (Hiepc) (H denotes a dissociable proton). [Pd(MeO-iepp)Cl] (2), [Pd(NO2-iepp)Cl] (3), and [Pd(iepc)Cl] (4) were prepared and revealed by X-ray analysis to have a pyridine nitrogen, an amine nitrogen, a phenolate or carboxylate oxygen, and a chloride ion in the coordination plane. UV absorption and 1H NMR spectral changes indicated that all the complexes could be converted to the indole-binding complexes where the O donor was replaced by the indole C2 atom by cyclopalladation in DMSO or DMF in the temperature range of 40-60 degrees C. Formation of the indole-binding complex species obeyed the first-order kinetics, from which the activation parameters were estimated. The formation rate was dependent on the properties of the O-donor group, a lower pKa value of its conjugate acid causing faster conversion to the indole-binding species in the order 2 (methoxyphenolate) < 3 (nitrophenolate) < 4 (carboxylate). On the other hand, the ratio of the indole-binding complex to the O-donor complex as a result of the conversion was greater for the complexes with a higher pKa value of the ligand OH group, the order being 2 > 3 > 4. 相似文献