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981.
Reflection filters have various applications in optical communication and other systems.In this letter,we propose a narrowband high-reflection filter composed of dielectric and metallic layers,in which an optimized filter combined with an admittance-matching layer with broad stop band is achieved.The structure can be expressed as Sub | (HL)13H2L(HL)313Cr0.84H | air,with full-width at half-maximum (FWHM) bandwidth of 2.5 nm.Based on this structure,reflection filters with multi-peaks are presented,and the law of distribution of peak positions is drawn. 相似文献
982.
Bin Yu 《Journal of Physics and Chemistry of Solids》2010,71(4):468-116
Casein, a natural biopolymer contained in milk, has been successfully intercalated into a Ca-Al-LDH host structure. Synthesis was performed by rehydration of tricalcium aluminate in the presence of casein. The resulting nanohybrids were characterized by powder X-ray diffraction (XRD), elemental analysis, infrared spectroscopy (IR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Further experiments revealed that the single protein strains intercalate instead of the entire casein sub micelles, which are present in milk. Additionally, the pure phospho protein fractions α- and β-casein, which make up ∼80 wt% of total casein were isolated and intercalated into the Ca-Al-LDH host structure, yielding a biopolymer-inorganic hybrid material. 相似文献
983.
984.
壳聚糖富集FAAS法测定水中痕量Cu(Ⅱ) 总被引:5,自引:1,他引:4
了以壳聚糖作富集柱,稀H2SO4为洗脱剂,稀NaOH为再生剂,火焰原子吸收光谱法简便,快速分离集测定水中痕量Cu(Ⅱ)的方法,于波长325nm处测定,检出限为为20ng.ml^0-1,线性范围为10-20μg.ml^-1。 相似文献
985.
Feldspar thermoluminescence fading phenomena were investigated here by using newly-constructed thermoluminescence spectrometer
on the basis of charge-coupled detector, and thereafter the discussion and explanation on feldspar TL fading mechanism were
presented. The experimental results show that the fading rate of feldspar TL depends on both wavelength and stimulated temperature,
and normally the feldspar TL in every region of wavelength and temperature shows different traits, namely the low temperature
TL (170°–190°) fading at the rate of logarithmic function and furthermore the TL of different wavelengths fading at approximately
the same rate on the condition of 160° preheating. While the medium and high temperature TLs (290°–400°) do not show much
thermal fading, their fading rate at room temperature invariably correlates well with their wavelength, namely the longer
TL wavelength, the slower TL fading rate. The thermal instability of traps and the quantum-mechanical tunneling effects can
explain the above fading phenomena respectively. It is recognized that feldspar TL fading depends on its wavelength, and furthermore
new aspects of the solid thermoluminescence process can be displayed by the combination of three-dimensional TL spectral analysis
and thermal fading or anomalous fading of TL for feldspar.
Supported by the National Natural Science Foundation of China (Grant No. 40534019) and the Knowledge Innovation Program of
the Chinese Academy of Sciences (Grant No. GIGCX3-07-10) 相似文献
986.
A new Hash function based on the generalized Henon map is proposed. We have obtained a binary sequence with excellent pseudo-random characteristics through improving the sequence generated by the generalized Henon map, and use it to construct Hash function. First we divide the message into groups, and then carry out the Xor operation between the ASCII value of each group and the binary sequence, the result can be used as the initial values of the next loop. Repeat the procedure until all the groups have been processed, and the final binary sequence is the Hash value. In the scheme, the initial values of the generalized Henon map are used as the secret key and the messages are mapped to Hash values with a designated length. Simulation results show that the proposed scheme has strong diffusion and confusion capability, good collision resistance, large key space, extreme sensitivity to message and secret key, and it is easy to be realized and extended. 相似文献
987.
Green and red up-conversion emissions and thermometric application of Er^3+-doped silicate glass 总被引:2,自引:0,他引:2 下载免费PDF全文
The green and red up-conversion emissions centred at about 534, 549 and 663 nm of wavelength, corresponding respectively to the ^2H11/2 → ^4I15/2, ^4S3/2 → ^4I15/2 and ^4F9/2 → ^4I15/2 transitions of Er^3+ ions, have been observed for the Er^3+-doped silicate glass excited by a 978 nm semiconductor laser beam. Excitation power dependent behaviour of the up-conversion emission intensity indicates that a two-photon absorption up-conversion process is responsible for the green and red up-conversion emissions. The temperature dependence of the green up-conversion emissions is also studied in a temperature range of 296-673 K, which shows that Er^3+-doped silicate glass can be used as a sensor in high-temperature measurement. 相似文献
988.
Bin Liu Rong Zhang Zili Xie XiangQian Xiu Liang Li Jieying Kong Huiqiang Yu Pin Han Shulin Gu Yi Shi Zheng YouDou Tang ChenGuang Chen YongHai Wang ZhanGuo 《中国科学G辑(英文版)》2008,51(3):237-242
InN films grown on sapphire at different substrate temperatures from 550°C to 700°C by metalorganic chemical vapor deposition
were investigated. The low-temperature GaN nucleation layer with high-temperature annealing (1100°C) was used as a buffer
for main InN layer growth. X-ray diffraction and Raman scattering measurements reveal that the quality of InN films can be
improved by increasing the growth temperature to 600°C. Further high substrate temperatures may promote the thermal decomposition
of InN films and result in poor crystallinity and surface morphology. The photoluminescence and Hall measurements were employed
to characterize the optical and electrical properties of InN films, which also indicates strong growth temperature dependence.
The InN films grown at temperature of 600°C show not only a high mobility with low carrier concentration, but also a strong
infrared emission band located around 0.7 eV. For a 600 nm thick InN film grown at 600°C, the Hall mobility achieves up to
938 cm2/Vs with electron concentration of 3.9 × 1018 cm−3.
Supported by the National Basic Research Program of China (Grant No. 2006CB6049), the National Natural Science Foundation
of China (Grant Nos. 6039072, 60476030 and 60421003), the Great Fund of the Ministry of Education of China (Grant No. 10416),
the Specialized Research Fund for the Doctoral Program of Higher Education of China (Grant No. 20050284004), and the Natural
Science Foundation of Jiangsu Province of China (Grant Nos. BK2005210 and BK2006126) 相似文献
989.
A new variable coefficient algebraic method and non-travelling wave solutions of nonlinear equations 下载免费PDF全文
In this paper, a new auxiliary equation method is presented of constructing more new non-travelling wave solutions of nonlinear differential equations in mathematical physics, which is direct and more powerful than projective Riccati equation method. In order to illustrate the validity and the advantages of the method, (2+1)-dimensional asymmetric Nizhnik-Novikov-Vesselov equation is employed and many new double periodic non-travelling wave solutions are obtained. This algorithm can also be applied to other nonlinear differential equations. 相似文献
990.
Via a cascaded structure, the peak-to-trough ratio is considerably improved for sampled fiber Bragg gratings (SFBGs) based on multiple-phase-shift (MPS) technique. This cascaded filter is composed of two identical SFBGs which are inserted with the increasing or decreasing arrangement of phase shifts. With this inverse arrangement of MPS in grating design, the phase fluctuation of individual SFBG can be compensated, and as a result an excellent phase matching condition is realized. In this way, the peak-to- trough ratio in reflection spectra is improved from 6 to 12 dB when multiplication factor m = 4, and from 5dBto 10dBwhenm=8. 相似文献