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101.
微条气体室(Micro-strip Gas Chamber,MSGC)探测器最严重的问题是电荷积累效应,通过选择合适的衬底材料可以有效的避免.为此,D263玻璃上沉积类金刚石(Diamond-like Carbon,DLC)膜来进行表面改性,从而制备DLC膜D/263玻璃双层结构作为MSGC衬底.拉曼光谱说明DLC膜是由sp3(σ键)和sp2(π键)杂化碳原子组成,属于电子导电型材料,并且沉积出的是一种高质量的DLC膜;I V曲线表明DLC膜改性后的样品具有非常稳定和理想的电阻率,其值在109—1012Ω·cm间;C-F曲线显示改性后样品具有小而稳定的电容.DLC膜D/263玻璃的优良性能正是MSGC衬底的最佳要求,这种新型材料用作衬底将有效克服电荷积累效应和衬底不稳定性. 相似文献
102.
In this paper we generalize to unbounded convex subsets C of hyperbolic spaces results obtained by W.A. Kirk and R. Espínola on approximate fixed points of nonexpansive mappings in product spaces (C×M)∞, where M is a metric space and C is a nonempty, convex, closed and bounded subset of a normed or a CAT(0)-space. We extend the results further, to families (Cu)u∈M of unbounded convex subsets of a hyperbolic space. The key ingredient in obtaining these generalizations is a uniform quantitative version of a theorem due to Borwein, Reich and Shafrir, obtained by the authors in a previous paper using techniques from mathematical logic. Inspired by that, we introduce in the last section the notion of uniform approximate fixed point property for sets C and classes of self-mappings of C. The paper ends with an open problem. 相似文献
103.
An unequally spaced fractal interpolation method is developed to reconstruct the low data rate laser Doppler velocimetry (LDV)
signal for better spectral results. The reconstructed result not only augments the data points to improve the statistics but
also retains the turbulent fractal dimension of the flow. In other words, the interpolated data are flow turbulence-correlated
data which are physically reasonable. This method is demonstrated on the LDV spectral measurements in the shear layer of a
jet flow and the results are compared against the hot-wire spectral data. When the data rate of the LDV signal is low, the
fractal interpolation method can suitably restore the major spectral peaks while the conventional sample-and-hold fails. Effects
of the data rate, data record length, sampling rate and the fractal dimension on the accuracy of the spectral reconstruction
are also discussed.
A version of this paper was presented at the 4th International Symposium on Transport Phenomena in Heat and Mass Transfer,
July 14–18, 1991, Sydney, Australia 相似文献
104.
Dr. Hiroshi Watanabe Ming-Long Yao Kunihiro Osaki Toshiyuki Shikata Hirokazu Niwa Yotaro Morishima 《Rheologica Acta》1997,36(5):524-533
Time-dependent nonlinear flow behavior was investigated for a model hard-sphere suspension, a 50 wt% suspension of spherical silica particles (radius = 40 nm; effective volume fraction = 0.53) in a 2.27/1 (wt/wt) ethylene glycol/glycerol mixture. The suspension had two stress components, the Brownian stress
B
and the hydrodynamic stress
H
After start-up of flow at various shear rates
, the viscosity growth function + (t,
) was measured with time t until it reached the steady state. The viscosity decay function – (t,
) was measured after cessation of flow from the steady as well as transient states. At low
where the steady state viscosity (
) exhibited the shear-thinning, the – (t,
) and + (t,
) data were quantitatively described with a BKZ constitutive equation utilizing data for nonlinear relaxation moduli G (t, ). This result enabled us to attribute the thinning behavior to the decrease of the Brownian contribution
B
=
B
/
(considered in the BKZ equation through damping of G (t, )). On the other hand, at high
where (
) exhibited the thickening, the BKZ prediction largely deviated from the + (t,
) and + (t,
) data, the latter obtained after cessation of steady flow. This result suggested that the thickening was due to an enhancement of the hydrodynamic contribution
H
=
H
/
(not considered in the BKZ equation). However, when the flow was stopped at the transient state and only a small strain (<0.2) was applied,
H
was hardly enhanced and the – (t,
) data agreed with the BKZ prediction. Correspondingly, the onset of thickening of + (t,
) was characterized with a
-insensitive strain ( 0.2). On the basis of these results, the enhancement of
H
(thickening mechanism) was related to dynamic clustering of the particles that took place only when the strain applied through the fast flow was larger than a characteristic strain necessary for close approach/collision of the particles. 相似文献
105.
Hsin-Ling Hsu Cheng-Fang Tien Jihperng Leu 《Journal of Solid State Electrochemistry》2014,18(6):1665-1671
This study develops a simple method to change the distribution of the pore size in a TiO2 layer, using polyethylene glycol (PEG), while maintaining nearly the same surface area and porosity to clarify how large pores affect the performance of dye-sensitized solar cells (DSSCs). Specifically, a heating step at 100 °C for a specific duration is added prior to PEG removal and TiO2 sintering at 400 °C. This process transforms the role of the PEG from a surfactant to a pore generator (porogen) and forms larger pores, depending on the loading and aggregation time for the PEG to gain larger pores. The effect of larger pores in TiO2 films under 30 % PEG loading, on the performance of an agarose gel electrolyte-based DSSC, was further investigated using the ionic liquid, 1-allyl-3-ethylimidazolium iodide (AEII). The I–V characteristic and the electrochemical impedance spectroscopy analysis show that larger pores readily improve redox couple diffusion in a TiO2 porous electrode and modify the interface between electrolyte and TiO2. Using the optimized TiO2 film with larger pores (30 % PEG loading, 100 °C/60 min), an efficiency of 7.43 % is achieved for the agarose gel electrolyte-based DSSC, which represents a 26.1 % improvement over TiO2 without the addition of PEG. 相似文献
106.
Tian‐Shung Wu Yann‐Ln Leu Yao‐Lung Tsai Fu‐Wen Lin Yu‐Yi Chan Chia‐Yu Chiang 《中国化学会会志》2001,48(1):109-112
Continuing our investigation on the bioactive compounds from the plant of the Aristolochia genus in Taiwan, we isolated one new sesquiterpene, aristololide, from the stem and roots of A. elegans, eleven known compounds from the fruits of A. elegans and nine known compounds from the fresh leaves of A. zollingeriana. Their structures were elucidated according to the 1D and 2D NMR spectroscopic analyses or by comparison with literature values. 相似文献
107.
Ching Hsuan Lin Sheng Xiong Cai Tsu Shang Leu Ting Yu Hwang Hao Hsin Lee 《Journal of polymer science. Part A, Polymer chemistry》2006,44(11):3454-3468
We propose three approaches to obtain flame‐retardant benzoxazines. In the first approach, we synthesize a novel benzoxazine (dopot‐m) from a phosphorus‐containing triphenol (dopotriol), formaldehyde, and methyl amine. Dopot‐m is copolymerized with a commercial benzoxazine [6′,6‐bis(3‐phenyl‐3,4‐dihydro‐2H‐1,3‐benzoxazineyl)methane (F‐a)] or diglycidyl ether of bisphenol A (DGEBA). The thermal properties and flame retardancy of the F‐a/dopot‐m copolymers increase with the content of dopot‐m. As for the dopot‐m/DGEBA curing system, the glass‐transition temperature of the dopot‐m/DGEBA copolymer is 252 °C, which is higher than that of poly(dopot‐m). The 5% decomposition temperature of the dopot‐m/DGEBA copolymer increases from 323 to 351 °C because of the higher crosslinking density caused by the reaction of phenolic OH and epoxy. In the second approach, we incorporate the element phosphorus into benzoxazine via the curing reaction of dopotriol and F‐a. After the curing, the thermal properties of the F‐a/dopotriol copolymers are almost the same as those of neat poly(F‐a), and this implies that we can incorporate the flame‐retardant element phosphorus into the polybenzoxazine without sacrificing any thermal properties. In the third approach, we react dopo with electron‐deficient benzoxazine to incorporate the element phosphorus. After the curing, the glass‐transition temperatures of polybenzoxazines decrease slightly with the content of dopo, mainly because of the smaller crosslinking density of the resultant polybenzoxazines. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3454–3468, 2006 相似文献
108.
Laurenťiu Leuštean 《Central European Journal of Mathematics》2003,1(3):382-397
In this paper we study the prime and maximal spectra of a BL-algebra, proving that the prime spectrum is a compact T
0 topological space and that the maximal spectrum is a compact Hausdorff topological space. We also define and study the reticulation
of a BL-algebra. 相似文献
109.
Abstract. An MV-convergence is a convergence on an MV-algebra which renders the operations continuous. We show that such
convergences on a given MV-algebra A are exactly the restrictions of the bounded -convergences on the abelian -group in which A appears as the unit interval. Thus the theory of -convergence and Cauchy structures transfers to MV-algebras.?We outline the general theory, and then apply it to three particular
MV-convergences and their corresponding Cauchy completions. The Cauchy completion arising from order convergence coincides
with the Dedekind-MacNeille completion of an MV-algebra. The Cauchy completion arising from polar convergence allows a tidy
proof of the existence and uniqueness of the lateral completion of an MV-algebra. And the Cauchy completion arising from α-convergence
gives rise to the cut completion of an MV-algebra.
Received August 8, 2001; accepted in final form October 18, 2001. 相似文献
110.
Jian-Hong Lee Min-Hsiung Hon Yi-Wen Chung Ing-Chi Leu 《Applied Physics A: Materials Science & Processing》2011,102(3):545-550
ZnO nanorods were coated with TiO2 thin film using the atomic layer deposition (ALD) process. X-ray diffraction, scanning electron microscopy, and transmission
electron microscopy were used to characterize the crystal structure and surface morphology of the coated composites. Results
of galvanostatic charge and discharge tests and cyclic voltammograms suggest that lithium ions can reversibly intercalate
into and deintercalate from TiO2-coated ZnO nanorods, and that stable cycling behavior in an ethylene carbonate-based electrolyte can be achieved. The TiO2 coating is believed to reduce the degree of reaction electrodes have with the electrolyte during the charge–discharge process
since the inactive coating layer prevents the electrode from having direct contact with the electrolyte. Furthermore, the
one-dimensional nanorods provide a relatively higher surface area than those of their bulk form or thin film, which allows
a much greater portion of atoms on the surface to undergo the electrochemical reaction. The electrochemical study indicates
that the TiO2-coated ZnO nanorod arrays might be a candidate for the anode material in Li-ion batteries. 相似文献