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排序方式: 共有967条查询结果,搜索用时 62 毫秒
11.
K Yamada K Senzaki Y Komori T Nikai H Sugihara T Nabeshima 《Canadian Metallurgical Quarterly》1997,762(1-2):72-78
The role of glial cells in nitric oxide production in the cerebellum of conscious rats was investigated with a glial selective metabolic inhibitor, fluorocitrate. The levels of nitric oxide metabolites (nitrite plus nitrate) in the dialysate following in vivo microdialysis progressively increased to more than 2-fold the basal levels during a 2-h infusion of fluorocitrate (1 mM), and the increase persisted for more than 2 h after the treatment. Pretreatment with N(G)-nitro-L-arginine methyl ester attenuated the fluorocitrate-induced increase in nitric oxide metabolite levels. None of the glutamate receptor antagonists, including D(-)-2-amino-5-phosphonopentanoic acid, 6,7-dinitroquinoxaline-2,3-dione, and (+/-)-alpha-methyl-4-carboxyphenylglycine, inhibited the fluorocitrate-induced increase. The L-arginine-induced increase was significantly reduced by fluorocitrate treatment, while N-methyl-D-aspartate, (+)-alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid, and trans-(+/-)-1-amino-(1S,3R)-cyclopentane-dicarboxylic acid increased nitric oxide metabolites levels in the fluorocitrate-treated rats, as much as in control animals. These results suggest that glial cells play an important role in modulating nitric oxide production in the cerebellum by regulating L-arginine availability. 相似文献
12.
We developed a noble technique for the fine-particle handling in plasmas. In this method a pair of point electrodes are introduced in the plasma, to which positive pulses are applied alternatively. When the pulse repetition period is shorter than the particle response time, the particles feel only time-averaged force because of their large mass. Spatial profile of the equivalent potential of the time-averaged force varies from a circle to an ellipse with an increase in the local discharge at the electrodes. The particles are eventually transported toward a middle point between two point-electrodes, being almost independent of their initial positions. This method is quite effective for converging fine particles in the plasma. 相似文献
13.
Yusuke Soraji Kazuo Furuta Taro Kanno Hisae Aoyama Satoru Inoue Daisuke Karikawa Makoto Takahashi 《Cognition, Technology & Work》2012,14(2):93-105
Since controller teams are in charge of en-route air traffic control, team cooperation is a key issue for good control performance. We conducted ethnographic field observation at the Tokyo Area Control Center and then analyzed the obtained data to develop a cognitive model of team cooperation in en-route air traffic control. We segmented conversational records, behavioral records, and so on by control unit, and then clarified relations between the segments and identified expert knowledge and judgment behind them. Cognitive processes of controller teams were reconstructed based on a concept of distributed cognition. The analysis revealed that the mutual belief model is applicable to team cooperation processes, the role assignment of tasks within a controller team is implicit and that control plans are implemented smoothly once team situation awareness has been established. A cognitive model of controllers?? team cooperation has been constructed based on these findings. 相似文献
14.
NICKEL ELECTROPLATING has been practicallyused for decades.There is an unknown part in theplating,although this is easy to plate.Applications ofthe plating are described from the practical viewpoint.Purpose of Nickel Electroplating(1)Decorative,and corrosion resistanceNickel electroplating is deposited on iron,cupper,zinc and aluminum substrate etc.,and chromiumplating is usually deposited on nickel plating.Hexavalent chromium plating has an important effecton the corrosion resisitan… 相似文献
15.
In Situ Observation of Phase Separation of a Barium Borate Melt in a Stable Immiscibility Region under Microgravity 总被引:1,自引:0,他引:1
Satoru Inoue Akio Makishima Hiroyuki Inoue Kohei Soga Tomoya Konishi Tomoyoshi Asano Yuu Ishii Masato Koyama 《Journal of the American Ceramic Society》1997,80(9):2413-2417
The precipitation of droplets was directly observed on a BaO–B2 O3 melt in a drop shaft experiment. This is the first time that precipitation of droplets has been observed in a 4.5 s drop test. The melt film of 4BaOz96B2 O3 (mol%) held on a platinum wire loop was heated above the critical tem-perature to produce uniformity and was cooled down to the phase separation temperature range. Phase separation of the melt was observed directly with a video camera. The IR image of the melt was simultaneously detected with a CCD array and was converted into a two-dimensional thermograph. 相似文献
16.
Saburo Komori Mitsuo Okahara Kenzo Okamoto 《Journal of the American Oil Chemists' Society》1960,37(10):468-473
Summary Since the long-chain fatty acid sucrose diesters inevitably produced in the synthesis of monoesters are only slightly soluble
in water, no important use can be found for them at the present time except as oilsoluble emulsifying agents.
In order to exploit new uses we have attempted to improve their solubility in water by introducing oxyethylene radicals into
the molecule.
The addition reaction of ethylene oxide with the sucrose diesters was carried out in an autoclave in the presence of alkaline
catalysts. With the reaction temperature maintained between 100–130° the pressure decreased as the reaction proceeded, and
one to two hours were required to consume the ethylene oxide used.
The addition products are yellow or orange oily materials soluble in water. Aqueous solutions showed good surface-active properties. 相似文献
17.
Masahiro Tajima Miki Niwa Yasushi Fujii Yutaka Koinuma Reiji Aizawa Satoshi Kushiyama Satoru Kobayashi Koichi Mizuno Hideo Ohuˆchi 《Applied catalysis. B, Environmental》1997,12(4):1418
The decomposition of chlorofluorocarbons (CFCs) in the presence of water was examined over a variety of solid acid catalysts. The TiO2ZrO2 catalyst was found to have the highest activity and longest life among the catalysts examined. The activity of the TiO2ZrO2 catalysts depended upon the content of TiO2. At the contents of TiO2 from 58 to 90 mole%, the TiO2ZrO2 catalysts exhibited high activity, and these catalysts were proven to contain TiZrO4 crystal. From the study of the XRD peak intensity of the TiZrO4 crystal, it was highest on the TZ-58 which contained 58 mole% of TiO2, and decreased with increasing the content of TiO2. Furthermore, the conversion of CFC113 measured at 673 K was highest at TZ-58, and decreased gradually with increasing TiO2 content. Therefore, the TiZrO4 crystal influences the activity of decomposition of CFC113. However, the TiO2ZrO2 catalyst was gradually deactivated during the reaction due to the elimination of titanium atoms. A good relationship was found between the activity on TiO2ZrO2 catalyst and bond energy of CCl in the compounds of chlorofluorocarbons and hydrochlorocarbons, suggesting that the rate controlling step was the cleavage of CCl bond. 相似文献
18.
Controlling the familywise error rate in functional neuroimaging: a comparative review 总被引:1,自引:0,他引:1
Functional neuroimaging data embodies a massive multiple testing problem, where 100,000 correlated test statistics must be assessed. The familywise error rate, the chance of any false positives is the standard measure of Type I errors in multiple testing. In this paper we review and evaluate three approaches to thresholding images of test statistics: Bonferroni, random field and the permutation test. Owing to recent developments, improved Bonferroni procedures, such as Hochberg's methods, are now applicable to dependent data. Continuous random field methods use the smoothness of the image to adapt to the severity of the multiple testing problem. Also, increased computing power has made both permutation and bootstrap methods applicable to functional neuroimaging. We evaluate these approaches on t images using simulations and a collection of real datasets. We find that Bonferroni-related tests offer little improvement over Bonferroni, while the permutation method offers substantial improvement over the random field method for low smoothness and low degrees of freedom. We also show the limitations of trying to find an equivalent number of independent tests for an image of correlated test statistics. 相似文献
19.
Single-walled carbon nanotube networks grown on SiO2 pillars were studied by means of scanning photoemission microscopy. The individual nanotubes or nanotube bundles growing from the pillar tops were observed in C 1s images. Band bending near catalytic Fe/nanotube contacts in an end-bonded configuration was studied by measuring C 1s spectra along the tube axes. Within our experimental resolution, no band bending was observed. This implies that the depletion width is less than the spatial resolution of the scanning photoemission microscope (90 nm) or that the amount of the band bending is less than 0.1 eV. 相似文献
20.
Lida T Nakamori R Yabuta R Yada S Takagi Y Mano N Ikegawa S Goto J Nambara T 《Lipids》2002,37(1):101-110
A facile and efficient synthesis of the carboxyl-linked glucosides of bile acids is described. Direct esterification of unprotected
bile acids with 2,3,4,6-tetra-O-benzyl-d-glucopyranose in pyridine in the presence of 2-chloro-1,3,5-trinitrobenzene as a coupling agent afforded a mixture of the
α- and β-anomers (ca. 1∶3) of the 1-O-acyl-d-glucoside benzyl ethers of bile acids, which was separated effectively on a C18 reversedphase chromatography column (isolated yields of α- and β-anomers are 4–9% and 12–19%, respectively). Subsequent hydrogenolysis
of the α- and β-acyl glucoside benzyl ethers on a 10% Pd−C catalyst in acetic acid/methanol/EtOAc (1∶2∶2, by vol) at 35°C
under atmospheric pressure gave the corresponding free esters in good yields (79–89%). Chemical specificities such as facile
hydrolysis and transesterification of the acyl glucosides in various solvents were also discussed. 相似文献