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排序方式: 共有101条查询结果,搜索用时 984 毫秒
31.
Malek M Morii M Fukuda S Fukuda Y Ishitsuka M Itow Y Kajita T Kameda J Kaneyuki K Kobayashi K Koshio Y Miura M Moriyama S Nakahata M Nakayama S Namba T Okada A Ooyabu T Saji C Sakurai N Shiozawa M Suzuki Y Takeuchi H Takeuchi Y Totsuka Y Yamada S Desai S Earl M Kearns E Messier MD Stone JL Sulak LR Walter CW Goldhaber M Barszczak T Casper D Gajewski W Kropp WR Mine S Liu DW Smy MB Sobel HW Vagins MR Gago A Ganezer KS Keig WE Ellsworth RW Tasaka S Kibayashi A Learned JG Matsuno S Takemori D 《Physical review letters》2003,90(6):061101
A search for the relic neutrinos from all past core-collapse supernovae was conducted using 1496 days of data from the Super-Kamiokande detector. This analysis looked for electron-type antineutrinos that had produced a positron with an energy greater than 18 MeV. In the absence of a signal, 90% C.L. upper limits on the total flux were set for several theoretical models; these limits ranged from 20 to 130 macro nu(e) cm(-2) s(-1). Additionally, an upper bound of 1.2 macro nu(e) cm(-2) s(-1) was set for the supernova relic neutrino flux in the energy region E(nu)>19.3 MeV. 相似文献
32.
Using the general connection between the upper limit on the neutrino mass and the upper limits on certain types of non-standard-model interactions that can generate loop corrections to the neutrino mass, we derive constraints on some non-standard-model d --> ue- nu interactions. When cast into limits on n --> pe- nu coupling constants, our results yield constraints on scalar and tensor weak interactions improved by more than an order of magnitude over the current experimental limits. When combined with the existing limits, our results yield absolute value(C(S)/C(V)) approximately < 5 x 10(-3), absolute value(C'(S)/C(V)) approximately < 5 x 10(-3), absolute value(C(T)/C(A)) approximately < 1.2 x 10(-2), and absolute value(C'(T)/C(A)) approximately < 1.2 x 10(-2). 相似文献
33.
Particle tracking velocimetry (PTV) is applied for measuring the motions of luminous particles in fireworks. The objective
of the study is to clarify the technical problems encountering in large-scale quantitative visualization in natural environment.
The major problems are found to be uncontrolled background in nature, low pixel resolution relative to particle size, and
large perspective. The ways to deal with these problems in current technological level are discussed. In the application,
two cameras are located at 1.3 km from the launching point with 30-degree opening angle to implement 3-D PTV. The transient
3-D velocity distributions of around 200 m-scale diameter fireworks are obtained during the light emission from the explosion
till burnout. Moreover, the evolution of the mean particle diameter that decreases continuously with the combustion is estimated
with the measured velocity information by the particles equation of motion. 相似文献
34.
Atomic force microscopy study on the stability of a surface film formed on a graphite negative electrode at elevated temperatures 总被引:1,自引:0,他引:1
Inaba M Tomiyasu H Tasaka A Jeong SK Ogumi Z 《Langmuir : the ACS journal of surfaces and colloids》2004,20(4):1348-1355
The stability at elevated temperatures of a solid electrolyte interphase (SEI) formed on a graphite negative electrode in lithium ion batteries was investigated by storage tests and in situ atomic force microscopy (AFM) observation. When the fully discharged graphite electrode was stored at elevated temperatures, the irreversible capacity in the following cycle increased remarkably. On the other hand, when the electrode was stored at the fully charged state at elevated temperatures, it was severely self-discharged during storage. AFM observation of the SEI layer formed on a model electrode of highly oriented pyrolytic graphite revealed two important facts on the stability of the SEI at elevated temperatures: (i) dissolution and agglomeration of the SEI layer at the discharged state and (ii) serious SEI growth at the charged state. These phenomena well explain the results of the charge and discharge tests. It was also shown that the addition of vinylene carbonate greatly improves the stability of the SEI at elevated temperatures, and gives good charge and discharge performance after storage. 相似文献
35.
Liu DW Ashie Y Fukuda S Fukuda Y Ishihara K Itow Y Koshio Y Minamino A Miura M Moriyama S Nakahata M Namba T Nambu R Obayashi Y Sakurai N Shiozawa M Suzuki Y Takeuchi H Takeuchi Y Yamada S Ishitsuka M Kajita T Kaneyuki K Nakayama S Okada A Ooyabu T Saji C Desai S Earl M Kearns E Messier MD Stone JL Sulak LR Walter CW Wang W Barszczak T Casper D Cravens JP Gajewski W Kropp WR Mine S Smy MB Sobel HW Sterner CW Vagins MR Ganezer KS Hill J Keig WE Kim JY Lim IT Ellsworth RW Tasaka S Kibayashi A 《Physical review letters》2004,93(2):021802
A search for a nonzero neutrino magnetic moment has been conducted using 1496 live days of solar neutrino data from Super-Kamiokande-I. Specifically, we searched for distortions to the energy spectrum of recoil electrons arising from magnetic scattering due to a nonzero neutrino magnetic moment. In the absence of a clear signal, we found micro(nu)=(3.6x10(-10))micro(B) at 90% C.L. by fitting to the Super-Kamiokande day-night spectra. The fitting took into account the effect of neutrino oscillation on the shapes of energy spectra. With additional information from other solar neutrino and KamLAND experiments constraining the oscillation region, a limit of micro(nu)=(1.1x10(-10))micro(B) at 90% C.L. was obtained. 相似文献
36.
K Umetsu M Tanaka I Yuasa N Saitou I Takeyasu N Fuku E Naito K Ago N Nakayashiki A Miyoshi S Kashimura G Watanabe M Osawa 《Electrophoresis》2001,22(16):3533-3538
A number of mutations in coding and noncoding regions of mitochondrial DNA (mtDNA) have previously been studied. In the present study, we simultaneously typed six mutation sites in the coding region by use of amplified product-length polymorphism (APLP) analysis. The mtDNA variations of 2471 individuals from 20 populations of Japanese, Korean, Chinese, and German were examined and classified into 18 haplotypes. Two of these haplotypes, B1 (estimated ancestral haplotype) and C1, were distributed among all populations tested. However, the haplotypes A1, A2, B2, B3, and C2 were mostly restricted to the Mongoloid populations, whereas haplotypes B5 and C5 appeared almost exclusively in the German population. Phylogenetic analysis by the neighbor-joining method revealed that the Japanese populations were more closely related to each other than to the other East Asian populations surveyed. The multiplex APLP method is suitable for large-scale screening studies of mtDNA variability because it is both rapid and economical. 相似文献
37.
Motoyuki Tasaka Kentaro Tanaka Motoo Shiro Mitsuhiko Shionoya 《Supramolecular chemistry》2013,25(6):671-675
Abstract An approach we have used in this study for the incorporation of metal ions into DNA, is the direct modification of a DNA base itself, turning it into a metal-chelating nucleobase wherein two nucleobases are paired through metal coordination. Herein we report the X-ray crystal structure of a synthetic intermediate 6 for the aminophenol bearing nucleoside 3 and its metal coordination properties with Pd2+. The anomeric configuration of the nucleoside was unequivocally determined to be β-form by the X-ray analysis of 6; the structure has been resolved by direct methods (S1R97) and expanded using Fourier techniques (DIRDIF94) using 2628 independent reflections with I>2.00 [sgrave](I) and 425 parameters. Final R (Rw) was 0.037 (0.043): orthorhombic, space group P212121 (#19) with a=16.562(1) Å, b=16.933(1) Å, c=11.205(1) Å, and V=3142.2(4) Å3; Dc =1.369g/cm3 for Z=4, and molecular weight 647.65. This result is consistent with the tentative assignment by our previous 1H NOE differentiation experiments. Detailed 1H NMR studies showed that the nucleoside forms a stable 2:1 complex with Pd2+ with concomitant deprotonation of its phenolic proton. Although there are two possible structures (cis or trans) for the square-planar Pd2+ complex, the ratio of cis to trans was approximately 1:1. The electrospray ionization time-of-flight mass spectrum of the complex also provided clear evidence for the 2:1 complexation. 相似文献
38.
A robust and rapid method for the determination of natural levels of beryllium (Be) in seawater was developed to facilitate mapping Be concentrations in the ocean. A solid-phase extraction method using a silica gel column was applied for preconcentration and purification of Be in seawater prior to determination of Be concentrations with inductively coupled plasma mass spectrometry (ICP-MS). Be was quantitatively adsorbed onto silica gel from solutions with pH values ranging from 6.3 to 9, including natural seawater. The chelating agent ethylenediamine tetraacetic acid was used to remove other ions in the seawater matrix (Na, Mg, and Ca) that interfere with the ICP-MS analysis. The reproducibility of the method was 3% based on triplicate analyses of natural seawater samples, and the detection limit was 0.4 pmol kg−1 for 250 mL of seawater, which is sufficient for the analysis of seawater in the open ocean. The method was then used to determine the vertical profile of Be in the eastern North Pacific Ocean, which was found to be a recycled-type profile in which the Be concentration increased with depth from the surface (7.2 pmol kg−1 at <200 m) to deep water (29.2 pmol kg−1 from 3500 m to the bottom). 相似文献
39.
N. Inagaki S. Tasaka K. Hibi 《Journal of polymer science. Part A, Polymer chemistry》1992,30(7):1425-1431
Kapton films were treated with seven plasmas: Ar-, N2-, O2-, CO-, CO2-, NO-, and NO2- plasmas. Surface properties and chemical composition of the plasma-treated Kapton films were investigated from the contact angle measurement, and the IR and XPS spectra. The plasmas, especially NO- and NO2-plasma, made the Kapton film surface hydrophilic. The XPS and IR spectra showed that the plasma led to the modification of the imide groups in the Kapton film to secondary amide and carboxylate groups. 相似文献
40.
R L Ohniwa K Morikawa J Kim T Kobori K Hizume R Matsumi H Atomi T Imanaka T Ohta C Wada S H Yoshimura K Takeyasu 《Microscopy and microanalysis》2007,13(1):3-12
Because of its applicability to biological specimens (nonconductors), a single-molecule-imaging technique, atomic force microscopy (AFM), has been particularly powerful for visualizing and analyzing complex biological processes. Comparative analyses based on AFM observation revealed that the bacterial nucleoids and human chromatin were constituted by a detergent/salt-resistant 30-40-nm fiber that turned into thicker fibers with beads of 70-80 nm diameter. AFM observations of the 14-kbp plasmid and 110-kbp F plasmid purified from Escherichia coli demonstrated that the 70-80-nm fiber did not contain a eukaryotic nucleosome-like "beads-on-a-string" structure. Chloroplast nucleoid (that lacks bacterial-type nucleoid proteins and eukaryotic histones) also exhibited the 70-80-nm structural units. Interestingly, naked DNA appeared when the nucleoids from E. coli and chloroplast were treated with RNase, whereas only 30-nm chromatin fiber was released from the human nucleus with the same treatment. These observations suggest that the 30-40-nm nucleoid fiber is formed with a help of nucleoid proteins and RNA in E. coli and chroloplast, and that the eukaryotic 30-nm chromatin fiber is formed without RNA. On the other hand, the 70-80-nm beaded structures in both E. coli and human are dependent on RNA. 相似文献