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1.
On investigating the longitudinally driven GMI effect of the DC annealed Fe36Co36Nb4Si4.8B19.2 alloy ribbon, the current density was 3.2×10^7 A/m^2, the GMI effect responds sensitively (the sensitivity is as high as 2440.2%/(A-m^-1)) to weak magnetic field after a 600-second annealing. The experimental result shows that the sensitivity is closely related to annealing current density, driven current frequency and eroded thickness. GMI effect, current annealing, sensitivity, magnetic domain structure  相似文献   

2.
We studied the multiple-channel filters based on photonic heterostructures consisting of single-negative permittivity and single-negative permeability media. The results showed that the number of resonance modes inside the zero-φeff gap increases as the number of heterogenous interface M increases. The number of resonance modes inside the zero-φeff, gap is equal to that of heterogenous interface M, and it can be used as M channels filter. This result provides a feasible method to adjust the channel number of multiple-channel filters. When losses are involved, the results showed that the electric fields of the resonance modes decay largely with the increase of the number of heterogenous interface and damping factors. Besides, the relationship between the quality factor of multiple-channel filters and the number of heterogenous interface M is linear, and the quality factor of multiple-channel filters decreases with the increase of the damping factor. These results provide feasible methods to adjust the quality factor of multiple-channel filters.  相似文献   

3.
Development of miniature HTSC wide-band filter with open-loop resonators   总被引:1,自引:0,他引:1  
The strong electric and magnetic coupled novel HTSC (high temperature superconductor) open-loop microstrip resonators are studied in this report and the traditional structure of open-loop resonators is improved. A miniature wide-band HTSC bandpass filter is developed by the novel structure, which is fabricated on YBCO/LaAIO3/YBCO substrate with dimensions of 14.8×9.6 mm^2. This filter is tested at 77 K, and the specifications are that the center frequency is 2230 MHz, the bandwidth is 455 MHz, and the best insertion loss is 0.14 dB in passband.  相似文献   

4.
Niobium-doped ZnO transparent conductive films are deposited on glass substrates by radio frequency sputtering at 300℃. The influence of O2/Ar ratio on the structural, electrical and optical properties of the as-deposited films is investigated by X-ray diffraction, Hall measurement and optical transmission spectroscopy. The lowest resistivity of 4.0×10^-4Ω· cm is obtained from the film deposited at the O2/Ar ratio of 1/12. The average optical transmittance of the films is over 90%.  相似文献   

5.
Activated by methylaluminoxane, mononuclear bis(hydroxyindanone-iminate)nickel complexes Ni[ArN=CC2H3(CH3)C6H2(R)O]2 (Ar = 2,6-i-Pr2C6H3, R=Me(1), R=CI(2), and R=H(3)) showed good activity for the styrene polymerization. The effect of many reaction parameters including the AI/Ni ratio, temperature, and reaction time on catalytic activities of catalytic systems and the molecular weights of the obrained polystyrene was ascertained. The highest activity of 1.34×10^5g(PS)·mol^-1(Ni)·h^-1 was obtained under the optimum reaction condition. The ^13C NMR spectra of the polymers revealed that the polymer was isotactic-rich atactic polystyrene. And the coordination mechanism was confirmed by the analyses of the polymer chain end-groups.  相似文献   

6.
Single supersaturated NaClO4 aerosol droplets on a quartz substrate were observed by a high-speed video camera for their morphologic changes with decreasing relative humidity (RH). The supersaturated droplets were found to form anhydrous NaClO4 at -10% RH. Three stages were roughly observed in this process, i.e., the main stem appearance, primary and secondary branches growth, and the deep dehydration. The main stem grew steadily and finished in 120 ms. Affected by both crystal precipitation and water evaporation, primary branches grew for 1200 ms, accompanied by a slower growth of secondary branches. The deep dehydration was more complicated, and lasted for a longer time.  相似文献   

7.
The meta-analysis method was applied to quantitatively investigate effects of the elevated ozone concentration ([O3]) on chlorophyll concentration, gas exchange and yield components of wheat. There were 39 effective references through Web of Science (ISI, USA) and Chinese journal full-text database (CNKI, China). The results of meta-analysis indicated that elevated [O3] decreased grain yield, grain weight, grain number per ear, ear number per plant and harvest index by 26%, 18%, 11%, 5% and 11%, respectively, relative to ambient air. The decrease in leaf physiological characters was much greater than that in yield when wheat was expose to elevated [O3], while light-saturated photosynthetic rate (Asat), stomatal conductance (Gs) and chlorophyll content (Chl) decreased by 40%, 31%, and 46%, respectively. The responses to elevated [O3] between spring wheat and winter wheat were similar. Most of the variables showed a linear decrease trend with an increase of [O3]. The most significant decrease for Asat, Gs and Chl was found in grain filling stage. Elevated [CO2] could significantly ameliorated or offset the detrimental effects caused by elevated [O3]. Supported by National Natural Science Foundation of China (Grant No. 30670387), Eco-Frontier Fellowship of the Ministry of Environment, Japan (Grant No. 07-C062-03) and Ministry of Science and Technology of People’s Republic China with 973 Project (Grant No. 2002CB410803)  相似文献   

8.
This paper evaluated pulping performance of 3-year-old field-grown transgenic poplar (Populus tremula × Populus alba). The transgenic poplar with anti-sense CCoAOMT had an about 13% decreased lignin content, in which a slight increment was found in S/G ratio. Chemical analysis showed that the transgenic poplar had significantly less benezene-ethanol extractive than that of control wood, but no significant differences were found in contents of ash, cold water extractive, hot water extractive, 1% NaOH extractive, holocellulose, pentosans and cellulose. Fiber assay demonstrated that down-regulation of CCoAOMT expression improved the fiber quality in transgenic poplar. Kraft pulping showed that lower lignin in transgenic poplar led to remarkable improved pulp quality and increased pulp yield.  相似文献   

9.
One technique based on the difference spectra was developed to study the state of water in supersaturated Mg(NO3)2 aerosols. The technique could be derived from the observation that the Raman scattering and infrared absorbance cross sections of molecular vibrations of interest remain practically constant from diluted solutions to supersaturated aerosols. The spectra of solvated water were obtained and primarily related to the first hydration layers of solute molecules in supersaturated Mg(NO3)2 aerosols. Based on this investigation, a chain structure was proposed to occur in the supersaturated Mg(NO3)2 aerosols at low relative humidities (RHs). Supported by National Natural Science Foundation of China (Grant Nos. 20673010 and 20640420450), “111” Project (Grant No. B07012), and China Postdoctoral Science Foundation (Grant No. 20070410466)  相似文献   

10.
n the present work, the phase transitions and relaxor behavior of (1−x)Pb(Mg1/3Nb2/3)O3-xPbTiO3 (PMN-PT, x = 0.2―0.4) ferroelectric ceramics have been investigated by means of X-ray diffraction, di-electric spectroscopy, the P-E hysteresis loop measurements and Raman scattering techniques. Structural analysis revealed that with the increase of PbTiO3 content, PMN-PT ceramics experienced a gradual phase transition process from rhombohedral to tetragonal. It is usually believed that such kinds of phase transitions resulted in the linear decrease of relaxation degree. Surprisingly, our analy-sis of the dielectric spectra revealed that the indicator of the degree of diffuseness γ reached the maximum value near morphotropic phase boundary (MPB) (x = 0.32), then decreased with the further increase of PbTiO3 content. The large dielectric relaxor feature near MPB may be attributed to the for-mation of ordered nanodomains, resulting from complex coexisting nanostructures. Further, the P-E hysteresis loop measurements and Raman analysis of the B-site cation order correlated well with the dielectric measurement results. It was found that the hysteresis loop squareness Rsq received the minimum value while the inverse of the value of full wide of half maximum (FWHM) of A1g mode reached the maximum value at MPB composition, which showed similar trends to γ.  相似文献   

11.
Solar ultraviolet radiation B (UVB) is known to have inhibitive effects on phytoplankton photosynthesis. UVB light decreases rapidly with increasing depth in the water column and exerts different degrees of UVB inhibitive effects on phytoplankton photosynthesis. In this study, the objectives were to quantify effects of UVB on phytoplankton photosynthesis and quantum yield, and to examine UVB effects on phytoplankton photosynthesis when light varies. The insitu experiments were conducted in Da Ya Bay, which is a semienclosed area in the subtropical South China. The results showed a significant reduction of photosynthetic rates and quantum yield in the presence of UVB. Maximum photosynthetic rates (Pmax) and maximum quantum yield (Φmax) were 11%-22% and 17%-49% less under solar radiation with UVB than without UVB. A simplified model was developed to describe the UVB biologically effective fluence rate (E*inh) as an exponential decay function of depth. Light-shift experiments, in which water samples from the surface and at depth of 4 m were divided into several subsamples, and each subsamples were then incubated at different depths with and without UVB in the water column, showed that phytoplankton from the deeper water (4 m) had more inhibitive rates by UVB than that from the surface when exposed to the same light condition.  相似文献   

12.
We demonstrate both theoretically and numerically that slow light can enhance the parametric process of silicon in photonic crystal line-defect waveguides. Specifically, to get the desired gain, the pump power for a given gain medium length or the gain medium length for given pump power can be reduced by (c/vgn)^2 when slow light waveguides are used, where n is the material index of conventional waveguide, vg is the group velocity of the slow light waveguide and c is the light velocity in vacuum.  相似文献   

13.
Silica gel-supported Fe(ll) (SiOFe) was prepared and used for heterogeneous degradation of sulforhodamine B (SRB) and 2,4-dichlorophenol (DCP) under visible irradiation (λ 〉 420 nm) as an effective catalyst. UV-visible spectra, and infrared Spectrophotometry (IR), fluorescence, total organic carbon (TOC) and electron spin resonance (ESR) measurements were employed to analyze the photoreaction products. The results showed that SRB could be efficiently degraded by SiOFe/H2O2 system under visible irradiation with 100% decolorization and 72.3% TOC removal after 180 min illumination. The results of ESR and fluorescence measurements indicated that the oxidative process was predominated mainly by the hydroxyl radical (.OH) generated in the system.  相似文献   

14.
This paper proposes a new infrared method to measure the start duration of GaAs substrate in chemical etching. When etching starts, the temperature of liquid-film will change because of heat release in the chemical reaction. As a result, the start duration of GaAs can be tested by collecting real-time in-frared thermal images in the course of temperature variation. Both theoretical analysis and experi-mental results show that the line shape liquid film of a 2-mm width is a good monitoring subject. By making use of the grey distribution change of a certain cross section of the line shape liquid film, the start duration of reaction between GaAs and H2SO4-H202-H20 is obtained. The start durations of reac-tion between GaAs substrate and H2SO4: H202: H20 (=5:1:50 and 15:3:50) solution are about 0.2 s and 0.3-0.4 s, respectively. This result and relative method will impulse the research of wet chemical etching technology of GaAs and so on.  相似文献   

15.
16.
The H5N1 avian influenza virus (AIV) has widely spread in Asia, Europe and Africa, making a large amount of economic loss. Recently, our research group has screened a common neutralizing mono-clonal antibody named 8H5, which can neutralize almost all H5 subtype AIV ever isolated so far. Obviously, this monoclonal antibody would benefit for research and development of the universal AIV vac-cine and design of the drug against H5N1 AIV in high mutation rate. In this study, the homology modeling was applied to generate the 3D structure of 8H5 Fab fragment, and "canonical structure" method was used to define the specified loop conformation of CDR regions. The model was subjected to energy minimization in cvff force field with Discovery module in Insight II program. The resulting model has correct stereochemistry as gauged from the Ramachandran plot calculation and good 3D-structure compatibility as assessed by interaction energy analysis, solvent accessible surface (SAS) analysis, and Profiles-3D approach. Furthermore, the 8H5 Fab model was subjected to docking with three H5 subtype hemagglutinin (HA) structures deposited in PDB (ID No: ljsm, 2ibx and 2fk0) respectively. The result indicates that the three docked complexes share a common binding interface, but differ in binding angle related with HA structure similarity between viral subtypes. In the light of the three HA inter-faces with structural homology analysis, the common neutralizing epitope on HA recognized by 8H5 consists of 9 incontinuous amino acid residues: Asp^58, Asn^72, Glu^112, Lys^113, lie^114, Pro^118, Ser^120, Tyr^137, Tyr^252 (numbered as for ljsm sequence). The primary purpose of the present work is to provide some insight into structure and binding details of a common neutralizing epitope of H5N1 AIV, thereby aiding in the structure-based design of universal AIV vaccines and anti-virus therapeutic drugs.  相似文献   

17.
Degenerate four-wave mixing measurements, using the 35 ps pulses at 532 nm, have been employed to investigate the third-order nonlinear optical parameters of two chromium tricarbonyl complexes η6-bonded to 3-amino-9-ethylcarbazole at either the NH2-substituted aryl ring (1) or the unsubstituted ring (2) and their precursor 3-amino-9-ethylcarbazole (AECz). The second-order hyperpolarizability y of the compounds 1 and 2 were found to be 42.9×10^-31 and 35.9×10^-31 esu, respectively, approximately one order of magnitude greater than AECz. The relation between the molecular structure and second-order hyperpolarizability of the compounds I and 2 was explored in detail based on the three-level model and the density functional theory (DFT) calculation. The theoretical results indicate that the spatial distribution of electron density has the profound role in the third-order nonlinear optical properties.  相似文献   

18.
In the 1910s, TiO2 began to be used in building materials as pigments and opacifier due to its excellent optical property. Since the photocatalytic property of TiO2 was observed in 1972, its application field was expanded to air cleaning and sterilization. Thereafter, people added TiO2 into building materials to develop novel and facile building materials. These materials were widely used for air cleaning, sterilization, self-cleaning, anti-fogging, decoration, and building cooling. The combination of building and other functions can serve simultaneously. Although TiO2-based building materials have bright prospects, some aspects such as improving the stability and enhancing photoactive performance of the materials are of importance for future research. Supported by the National High Technology Research and Development Program (“863” Program) of China (Grant No. 2007AA061402), Chinese Key Technology Research and Development Program of the Eleventh Five-year Plan (Grant No. 2006BAJ02A08), Hangzhou Science & Technology Development Program (Grant No. 20061133B27) and Research Fund for the Doctoral Program of Higher Education (Grant No. 20070335197)  相似文献   

19.
Three strong earthquakes with magnitudes of Mw 8.4, Mw 7.9 and Mw 7.0 occurred in the sea west of Sumatra Island on September 12 and 13, 2007. We relocated the epicenters and focal depths of the three events by means of the reversal-time imaging technique using broadband digital seismic data from worldwide stations ranging from 30° to 90°, imaged the spatiotemporal variation of the energy radiation sources by means of the nonplane wave array technique using the broadband digital seismic data from a generalized array made up of 33 stations of the Capital Region Digital Seismograph Network (CRDSN), and obtained the rupture duration times, extents and rupture velocities. Also, we discussed the correlations between the locations of the energy radiation sources of the three events.  相似文献   

20.
An exceptionally well-preserved fossil Kalligrammatid from the Jehol Biota   总被引:1,自引:0,他引:1  
A new species of Neuroptera, Sophogramma lii sp. nov. is described and illustrated in this paper. This new species is assigned to Sophogramma Ren of Kalligrammatidae, mainly based on its humeral recurrent veins, the basal cell present between posterior branch of media at base of wing, etc. The new species is distinguished from all other Sophogramma species on the difference of wing venation. This exceptionally well-preserved specimen is recovered from the Yixian Formation, Huangbanjigou, located near Beipiao City, in western Liaoning Province. The genus diagnosis has been emended based on new characters shown in this new species. Based on a summary of localities, distribution and geological ages of all genera and species of the Kalligrammatidae, we suggest that Kalligrammatids might have originated in Eastern Asia, especially in China. Function of the wing pigmentation is discussed briefly. Supported by National Natural Science Foundation of China (Grant Nos. 30430100 and 40872022), Beijing Natural Science Foundation Program (Grant No. 5082002), Scientific Research Key Program (Grant No. KZ200910028005) and PHR Project of of Beijing Municipal Commission of Education, Science-Technology Basic Condition Platform from the Ministry of Science and Technology of the People’s Republic of China (Grant No. 2005DKA21402)  相似文献   

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