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131.
132.
Senoy Thomas D. Sakthikumar Yasuhiko Yoshida M. R. Anantharaman 《Journal of nanoparticle research》2008,10(1):203-206
Sol–gel glasses with Fe3O4 nanoparticles having particle sizes laying in the range 10–20 nm were encapsulated in the porous network of silica resulting
in nanocomposites having both optical and magnetic properties. Spectroscopic and photoluminescence studies indicated that
Fe3O4 nanocrystals are embedded in the silica matrix with no strong Si–O–Fe bonding. The composites exhibited a blue luminescence.
The optical absorption edge of the composites red shifted with increasing concentration of Fe3O4 in the silica matrix. There is no obvious shift in the position of the luminescence peak with the concentration of Fe3O4 except that the intensity of the peak is decreased. The unique combinations of magnetic and optical properties are appealing
for magneto–optical applications. 相似文献
133.
在传统光学电流传感器技术的基础上,提出了一种四光路光学电流传感器,其通过四路输出信号可准确确定偏转角,使电流的测量范围不受正弦函数的单调性的限制,从而提高了电流的测量范围。配合四光路结构,提出了新的反正切函数数据处理方法,其不存在角度不灵敏区、可纠正原始数据的缺陷,从而提高了测量精度。实测了充电电压为4.5 kV、电容为50 μF和导线有效穿过磁光探头14次的快开快门的总短路电流,其峰值达85 kA,与理论值87 kA能较好地吻合,从而证明了四光路光学电流传感器可有效地测量脉冲大电流。 相似文献
134.
Under small-signal assumption, equivalent noise figure normalized by fiber nonlinearities (NENF) of bi-directionally pumped distributed fiber Raman amplifiers (BiDFRA) is derived. Amplified spontaneous Raman scattering noise and double Rayleigh scattering noise are both included. The relation between NENF and Raman gain, forward Raman gain percentage is investigated under different polarization factor and Rayleigh scattering coefficient. It agrees well with numerical simulation results. Based on the analytical expression, the optical signal-to-nose ratio (OSNR) improvement of hybrid pre-BiDFRA/erbium-doped fiber amplifier (EDFA) compared with sole EDFA is studied. It is shown that there is an optimum Raman gain and forward Raman gain percentage to maximize the OSNR improvement. Finally, some guidelines on BiDFRA design are proposed. 相似文献
135.
单纯形法计算薄膜常数 总被引:1,自引:0,他引:1
本文首次报道了用单纯形加速法计算正常兔IgG抗原与羊-抗兔抗体反应的抗体层厚度和光学常数,该方法假定抗体层厚度、光学常数均为时间的函数,避免了以往只假定厚度为时间函数所造成的误差。结果表明该方法计算抗体层薄膜常数是可行的。 相似文献
136.
We report simulations concerning optical amplification in Er:Ti:LiNbO3 curved waveguides. The derivation and the evaluation of the spectral optical gain, the spectral noise figure, the amplified spontaneous emission photon number, and the signal to noise ratio are performed under the small gain approximation. The simulations show the evolution of these parameters under various pump regimes, Er concentration profiles and waveguide lengths. The results obtained are of significant interest for the design of complex, rare earth-doped integrated optics structures involving bent waveguides. 相似文献
137.
138.
Measurement Accuracy in Phase-Shifting Point Diffraction Interferometer with Two Optical Fibers 总被引:1,自引:0,他引:1
Toshiaki Matsuura Satoru Okagaki Takaaki Nakamura Yasushi Oshikane Haruyuki Inoue Motohiro Nakano Toshihiko Kataoka 《Optical Review》2007,14(6):401-405
A phase-shifting point diffraction interferometer (PS/PDI) with point sources of two single mode optical fibers has been developed,
which will be appropriate for the surface figure measurement of large aperture optics on a sub-nanometer scale. To reduce
the measurement error factors, a fiber optic plate (FOP) is used as a projection plane for interference pattern. Errors caused
by imperfection of optical alignment, such as position of point sources and tilt of FOP, are minimized by analyzing the measured
phase data with an original method. Measurement accuracy in the PS/ PDI is estimated with the interference pattern produced
by the two optical fiber sources. If inhomogeneity of the FOP and a systematic error of the PS/PDI are eliminated, the measurement
accuracy of the present system is estimated to be less than 4nm P-V and 0.7nm rms, respectively, at a measurement wavelength
of 632.8 nm. 相似文献
139.
Dorin Dusciac Jean-Noël Chazalviel François Ozanam Philippe Allongue Catherine Henry de Villeneuve 《Surface science》2007,601(18):3961-3964
Direct grafting of organic monolayers on Si is of prime interest in order to give specific properties to a silicon surface. However, for microelectronics applications, this possibility is hampered by the limited stability of the grafted layers. It has been previously established that alkyl layers attached to Si surfaces through Si-C bonds become unstable at 250-300 °C, by desorption of alkenes. Changing the nature of the bonding to the surface might allow one to circumvent this desorption pathway and increase the layer stability. In our work, decanol and decyl aldehyde are reacted with the Si(1 1 1)-H surface at ∼100 °C during 20 h in order to obtain alkoxy monolayers. FTIR measurements performed in ATR geometry show that the grafted molecule surface coverage is on the order of 33% after reaction with decanol and 50% after reaction with decyl aldehyde. Characterization by AFM essentially reveals that the morphology of the grafted surfaces is unaffected as compared to that of Si-H surfaces. However, the edges of the terraces at alcohol-grafted surfaces exhibit some pitting, probably due to the presence of water in the grafting liquid. Thermal stability studies show that alkoxy chains progressively disappear from the Si surface between 200 and 400 °C. From the CH2/CH3 ratio in the CH region (2760-3070 cm−1), it appears that the chains undergo progressive dissociation by C-C bond breaking before their complete disappearance from the surface. Therefore, the thermal behaviour of alkoxy monolayers appears quite distinct from that of alkyl monolayers that tend to leave the surface in a much narrower temperature range (250-350 °C), essentially via breaking of the Si-C bonds. 相似文献
140.
Micelles,microemulsions.vesicles,etc.,areorganicmicroheterogeneousmedia.Useofthesemediainanalyticalreactionsfordevelopingnewkinetic-baseddeterminationsorimprovingpreviouslyestablishedkineticmethodshasbeenreported"2.Inrecentyears,amixedmicellarmediumc... 相似文献