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131.
Eiji Kita Ayumu Hatanaka Kenji Nakajima Masakazu Nishi Kiiti Siratori 《Journal of Physics and Chemistry of Solids》2007,68(11):2166-2169
For the determination of the magnetic structure, elimination of the magnetic domains is indispensable and the appropriate stress will be effective when the crystal has a structural transformation at TN. The effect of uniaxial stress cooling on the neutron magnetic scattering in a ZnCr2O4 single crystal was studied. The pressure axis was set parallel to the [1 0 0] or [0 0 1], parallel or perpendicular to the diffraction plane, (0 0 1). The [1 0 0] pressure cooling increases one half-integer spots along the [1 0 0], whereas decreases others. The [0 0 1] pressure cooling increases two half-integer spots in the (0 0 1) plane, whereas decreases one half-integer spots. 相似文献
132.
K. Nishi Y. Hatsukade S. Tanaka K. Awazu H. Horiike 《Infrared Physics & Technology》2008,51(5):463-467
Since the discovery of high-temperature cuprate superconductors, there has been much intensive study about the mechanism of them. However, identifying the dynamical mechanism behind them remains one of the great challenges in condensed matter physics. We investigated the high-temperature YBa2Cu3O7−x superconducting films by using a free electron laser (FEL). The method is a type of photoelectron spectroscopy called a free electron laser internal photoemission. The spectrum of the photocurrent induced by FEL was measured in the case of 15 K and 100 K. We estimated the superconductive gap energy of YBa2Cu3O7−x by comparing the photocurrent spectrum of the superconductive state with that of non-superconductive state. 相似文献
133.
In this paper, the numerical analysis is given which is applicable for a TEA-CO2 laser pumping in search of effective pumping method.The analysis also can estimate the optimum pressure for a given molecule and a given pulse laser.Also we report in this work many FIR laser emissions from population inversion transition which have never observed before using a TEA-CO2 laser. 相似文献
134.
N. Nishi 《Zeitschrift für Physik D Atoms, Molecules and Clusters》1990,15(3):239-255
A new approach to solution chemistry and cluster physics has been developed by combining molecular beam mass-spectrometry with liquid jet expansion method. Many features characteristic of molecular association in aqueous solution were observed in the cluster mass spectra and some of them showed good agreement with reported values of enthalpy changes and entropy changes for molecular association-dissociation equilibria in liquid phase. Although it lacks persuadable theoretical analysis at this stage, several new findings obtained by this technique are introduced to appeal its potentialities of physical analysis of solution systems at molecular levels. 相似文献
135.
136.
Preparation of DNA-loaded polysulfone microspheres by liquid-liquid phase separation and its functional utilization 总被引:1,自引:0,他引:1
DNA-loaded polysulfone (PSf) microspheres were fabricated by means of a liquid-liquid phase separation technique. The porous microspheres were then used to remove DNA-binding intercalating materials--ethidium bromide, acridine orange, and endocrine disruptors. The DNA-loaded PSf microspheres are stable in water. The stability of the DNA-loaded microspheres and/or the release rate of DNA from the microspheres can be controlled by manipulating the microsphere structure. Increasing the polymer concentration, which causes lower porosity and smaller pores on the outer surface of the microspheres, led to increased stability of the microspheres and decreased release rate of DNA. Additionally, the drying temperature also affected the stability of the microspheres. The DNA-loaded PSf microspheres could effectively accumulate harmful DNA-intercalating pollutants and endocrine disruptors, such as ethidium bromide, acridine orange, biphenyl, dibenzofuran, and dibenzo-p-dioxin. The amount of pollutants removed by the microspheres is dependent on the amount of incorporated DNA and on the microsphere structure. The DNA-loaded microspheres have the potential to be used in environmental applications. 相似文献
137.
Exposure of 1-alkynyl[p-(trifluoromethyl)phenyl](tetrafluoroborato)-lambda(3)-bromanes to sodium benzenesulfinate or sodium trifluoromethanesulfinate in dichloromethane at 0 degree C under argon resulted in tandem Michael-carbene insertion reactions to produce 1-sulfonylcyclopentenes selectively, with concomitant formation of a small amount of rearranged 1-alkynyl sulfones. 相似文献
138.
Strange W Bohn OS Trent SA Nishi K 《The Journal of the Acoustical Society of America》2004,115(4):1791-1807
Current theories of cross-language speech perception claim that patterns of perceptual assimilation of non-native segments to native categories predict relative difficulties in learning to perceive (and produce) non-native phones. Cross-language spectral similarity of North German (NG) and American English (AE) vowels produced in isolated hVC(a) (di)syllables (study 1) and in hVC syllables embedded in a short sentence (study 2) was determined by discriminant analyses, to examine the extent to which acoustic similarity was predictive of perceptual similarity patterns. The perceptual assimilation of NG vowels to native AE vowel categories by AE listeners with no German language experience was then assessed directly. Both studies showed that acoustic similarity of AE and NG vowels did not always predict perceptual similarity, especially for "new" NG front rounded vowels and for "similar" NG front and back mid and mid-low vowels. Both acoustic and perceptual similarity of NG and AE vowels varied as a function of the prosodic context, although vowel duration differences did not affect perceptual assimilation patterns. When duration and spectral similarity were in conflict, AE listeners assimilated vowels on the basis of spectral similarity in both prosodic contexts. 相似文献
139.
The flow field and the energy transport near thermoacoustic couples are simulated using a 2D full Navier-Stokes solver. The thermoacoustic couple plate is maintained at a constant temperature; plate lengths, which are "short" and "long" compared with the particle displacement lengths of the acoustic standing waves, are tested. Also investigated are the effects of plate spacing and the amplitude of the standing wave. Results are examined in the form of energy vectors, particle paths, and overall entropy generation rates. These show that a net heat-pumping effect appears only near the edges of thermoacoustic couple plates, within about a particle displacement distance from the ends. A heat-pumping effect can be seen even on the shortest plates tested when the plate spacing exceeds the thermal penetration depth. It is observed that energy dissipation near the plate increases quadratically as the plate spacing is reduced. The results also indicate that there may be a larger scale vortical motion outside the plates which disappears as the plate spacing is reduced. 相似文献
140.
Strange W Akahane-Yamada R Kubo R Trent SA Nishi K 《The Journal of the Acoustical Society of America》2001,109(4):1691-1704
This study investigated the extent to which adult Japanese listeners' perceived phonetic similarity of American English (AE) and Japanese (J) vowels varied with consonantal context. Four AE speakers produced multiple instances of the 11 AE vowels in six syllabic contexts /b-b, b-p, d-d, d-t, g-g, g-k/ embedded in a short carrier sentence. Twenty-four native speakers of Japanese were asked to categorize each vowel utterance as most similar to one of 18 Japanese categories [five one-mora vowels, five two-mora vowels, plus/ei, ou/ and one-mora and two-mora vowels in palatalized consonant CV syllables, C(j)a(a), C(j)u(u), C(j)o(o)]. They then rated the "category goodness" of the AE vowel to the selected Japanese category on a seven-point scale. None of the 11 AE vowels was assimilated unanimously to a single J response category in all context/speaker conditions; consistency in selecting a single response category ranged from 77% for /eI/ to only 32% for /ae/. Median ratings of category goodness for modal response categories were somewhat restricted overall, ranging from 5 to 3. Results indicated that temporal assimilation patterns (judged similarity to one-mora versus two-mora Japanese categories) differed as a function of the voicing of the final consonant, especially for the AE vowels, /see text/. Patterns of spectral assimilation (judged similarity to the five J vowel qualities) of /see text/ also varied systematically with consonantal context and speakers. On the basis of these results, it was predicted that relative difficulty in the identification and discrimination of AE vowels by Japanese speakers would vary significantly as a function of the contexts in which they were produced and presented. 相似文献