Synthesis of nanoscale inorganic crystals with controlled size, shape, and hierarchy has attracted intensive research interest, since they are potential building blocks for advanced materials and optoelectronic device...
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ISBN:
(纸本)0978921739
Synthesis of nanoscale inorganic crystals with controlled size, shape, and hierarchy has attracted intensive research interest, since they are potential building blocks for advanced materials and optoelectronic devices. As an important group II-IV semiconductor with extensive applications in optical and electronic nanodevices, complex three-dimensional nanocrystals CdS with well-defined structures have just received great attentions since they offer new opportunities as building blocks to fabricate or assemble into advanced materials for further generation of optoelectronic devices, we report for the first time to large-scale synthesize an interesting 3D structured CdS nanocrystals by a facile hydrothermal method. The photoluminescence results of the 3D CdS nanocrystal indicated they have the potential applications for the building blocks on optoelectronic devices.
Sintering behavior of pure and Nb-doped barium titanate powders prepared by high-gravity reactive precipitation (HGRF) process was investigated. A thermal dilatometer was employed to monitor the sintering shrinkage co...
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Sintering behavior of pure and Nb-doped barium titanate powders prepared by high-gravity reactive precipitation (HGRF) process was investigated. A thermal dilatometer was employed to monitor the sintering shrinkage continuously during sintering. TEM and SEM were used to characterize the microstructures of the samples. The experimental results confirmed that Nb-doped BaTiO3 ceramics sintered at 1220°C for 2 h reached a larger densification of 97.0% relative density compared with 94.6% of pure BaTiO3 ceramics sintered at 1265°C for 2 h, and Nb-doped BaTiO3 ceramics had a smaller grain size (1.2μm) than that of pure BaTiO3 ceramics (2μm).
Precursors of calcium strontium zirconate (Ca0.8Sr 0.2ZrO3) were synthesized by oxalate coprecipitation method. TG-DTA was used to characterize the thermal decomposition behaviors of the precursors. The XRD results re...
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Precursors of calcium strontium zirconate (Ca0.8Sr 0.2ZrO3) were synthesized by oxalate coprecipitation method. TG-DTA was used to characterize the thermal decomposition behaviors of the precursors. The XRD results revealed that the powders crystallized as cubic Ca0.8Sr0.2ZrO3 with increasing heating temperature up to 1000°C. Calcium strontium zirconate ceramics were obtained under conventional sintering conditions by using the as-prepared Ca 0.8Sr0.2ZrO3 powders. The SEM micrographs of the ceramics sintered at 1450°C exhibited narrow grain-size distribution with the average grain size around 0.7 μm. The dielectric properties showed that, dielectric constant of the Ca0.8Sr0.2ZrO3 was about 24.0 and dielectric loss was 0.002 at the frequency of IGHz and the room temperature.
It is necessary for 319 aluminium alloy castings to be heat treated (in T6 condition) for the improvement of their mechanical properties. However, heat treatment needs not only cycle time but also energy cost. The hea...
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A small piece of 〈110〉 orientated relaxor-based ferroelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystals was embedded in Pb(Mg1/3Nb2/3)O 3-Pb(Ni1/3Nb2/3)O3-PbTiO 3 (PMN-PNN-PT) polycrystalline matrix to form the...
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A small piece of 〈110〉 orientated relaxor-based ferroelectric Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) single crystals was embedded in Pb(Mg1/3Nb2/3)O 3-Pb(Ni1/3Nb2/3)O3-PbTiO 3 (PMN-PNN-PT) polycrystalline matrix to form the fully dense disk by spark plasma sintering (SPS) technique. Specimens were subsequently annealed to promote the boundary migration of the template single-crystal through a process termed as solid-state single crystal growth. It was found that the addition of excess 5 wt% PbO can promote the crystal growth, and the 2D morphology with V-shaped single crystals of PMN-PNN-PT were also observed. The possible growth mechanism was discussed.
The dosages of two different polynaphthalene sulphonate superplasticizers (PNS) were selected according to the adaptability index including fluidity of cement paste, water-reducing ratio, and slump and strength develo...
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The dosages of two different polynaphthalene sulphonate superplasticizers (PNS) were selected according to the adaptability index including fluidity of cement paste, water-reducing ratio, and slump and strength development of concrete. On this base, it was experimental studied that the effect of two PNS on fluidity, cracking sensitivity, dry and wetting deformation of the same cement mortars. The results showed that cement mortars mixed with the two PNS had the same initial fluidity and fluidity change vs time, but took on different initial cracking time and linear deformation. This indicated that the effect of PNS on shrinkage Deformation of cement-based materials should be considered when selecting high range water reducing admixtures. The results also demonstrated that the higher content of Na2SO4 in PNS (or cement) would increase the cracking sensitivity of cement-based materials besides affect the application of PNS.
To apply the controlled source time-domain electromagnetic method in the sea-floor exploration. The coplanar magnetic dipole-dipole (HZHZ) configuration is adopted in this paper. The sea-floor transient electromagneti...
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Amorphous carbon (a-C) and carbon nitrogen (a-CN) films were synthesized using plasma immersion ion implantation and deposition (PIII-D) under different N2 flow at room temperature (R.T.). Lifshitz-van der Waals/acid-...
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Amorphous carbon (a-C) and carbon nitrogen (a-CN) films were synthesized using plasma immersion ion implantation and deposition (PIII-D) under different N2 flow at room temperature (R.T.). Lifshitz-van der Waals/acid-base approach (LW-AB) was introduced in order to study films' surface energy deeply. The results showed that the capability of the surface of the film on receive electron changed with N2 flow, which effected platelet adhesion of film strongly. Hall effects tests were employed to characterize the electrical properties of the films. The results showed that the as-deposited films exhibited n-type semiconductor characteristic, and carrier concentration of the films decreased with N2 flow increasing. Raman spectra with 514nm laser-source were employed to analyze the structural of the films.
Since the current rate control schemes in H.264 do not present the capability of efficient GOP-level bit allocation, the video quality varies greatly for sequences with the scene change or the scene complexity varying...
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ISBN:
(纸本)9780863418365
Since the current rate control schemes in H.264 do not present the capability of efficient GOP-level bit allocation, the video quality varies greatly for sequences with the scene change or the scene complexity varying from one GOP to another. To overcome the limitation, we propose a novel rate control scheme based on incremental PID algorithm. The incremental PID algorithm is introduced to minimize video quality variations in GOP-level bit allocation. Extensive simulation results show that the proposed rate control scheme, without expensive computational complexity added, decreases the average video quality variations by 15.07%.
Rutile titanium oxide films were fabricated by reactive unbalanced magnetron sputtering. The blood compatibility is evaluated in vitro by clotting time and platelet adhesion measurement. The surface valence band elect...
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Rutile titanium oxide films were fabricated by reactive unbalanced magnetron sputtering. The blood compatibility is evaluated in vitro by clotting time and platelet adhesion measurement. The surface valence band electronic structure is gained by the XPS valence band spectra. The rutile titanium oxide films exhibit attractive hemocompatibility. The result of the valence band electronic structure of the films on the surface indicated that the rutile titanium oxide film represent an n-type semiconductor characteristics and the characters result in the prevention of the charge transfering between the blood and materials and overall excellent antithrombogenic properties.
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