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文中主要针对斯特林碟架,设计了以ARM处理器和可编程逻辑控制器(PLC)为控制核心,视日运行轨迹跟踪与图像处理相结合的混合跟踪方式实现太阳自动跟踪.首先,利用太阳位置算法(SPA)定位太阳位置,确保太阳光斑在摄像头视场范围内;其次,使用CMOS图像传感器采集太阳图像,通过ARM处理器处理图像获取太阳跟踪角度误差;最后利... 相似文献
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《Ceramics International》2020,46(14):22661-22673
Characteristics of ZrB2–SiC ultrahigh temperature ceramic matrix composites (UHTCMCs) reinforced with ZrC and carbon fiber (Cf) were investigated in this article. Spark plasma sintering (SPS) process was utilized to fabricate the samples at 1800 °C for 5 min under 30 MPa punch pressure and vacuumed atmosphere. In all samples, the volume ratio of ZrB2: SiC was equal to 4:1, and the summation of ZrC and Cf reinforcements was 7.5 vol% with different ZrC: Cf ratios. Field emission scanning electron microscopy (FE-SEM), energy dispersive spectroscopy (EDS), densitometry, flexural strength, and hardness measurements were employed for characterization of the prepared samples. Microstructural inspection revealed the formation of SiC sheath around the carbon fibers due to several reactions in the surface SiO2 layers existed on the SiC particles. Optimal flexural strength (628.4 MPa) and hardness (20.8 GPa) values were achieved for the sample co-reinforced with 6.5 vol% ZrC and 1 vol% Cf, with a relative density of 97.7%. 相似文献
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《Ceramics International》2020,46(3):2640-2647
B2O3 and Li2O (B/L)-added Ba0.6Sr0.4TiO3 (BST) ceramics sintered at 940 °C exhibited a dense microstructure with large grains. The amount of B/L additive was 4.5 wt% with a B/L ratio of 1.5:1. The B/L-related liquid phase assisted the densification of the BST ceramics. This BST ceramic displayed a large dielectric constant (εr) of 2834 with a low dielectric loss (tan δ) of 0.21% at 1.0 MHz. It also displayed a large tunability (28.2% at 10 kV/cm) and a high figure of merit (FOM) of 134. BST thick-films were synthesized using the tape casting method. The thick-film densified at 940 °C exhibited a large tunability of 18.7% at 10.0 kV/cm and an FOM of 208; these are higher than the values reported in the literature. Multilayer ceramics (MLCs) consisting of five layers of 40-μm-thick BST thick-films and Ag electrodes were also fabricated at 940 °C. No diffusion occurred between the Ag electrode and BST thick-film. A large tunability of 67.6% at 52 kV/cm with a high FOM of 294 was obtained from this MLC. This verified that the B/L-added BST ceramic is effective for application in tunable multilayer devices. 相似文献
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To explore the crucial driving forces and dynamics of the Chinese apparel industry cluster, the authors analysed current situations, characteristics and the dilemma in the Chinese apparel industry based on surveys conducted in the Yangtze River Delta. This study classified the factors impacting apparel industry cluster development into necessary conditions and evolutionary factors according to logistic differential equation, and proposed a dynamics model framework of apparel industry cluster with positive and negative feedback mechanism. The authors believe that the Chinese apparel industry cluster is an ecology system involving outsourcing, specialisation agglomerating, competition, resource complementary, etc. and has a quick response ability of adapting to environment. 相似文献
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《Ceramics International》2017,43(18):16753-16762
The Y-TiO2/graphene heterojunctions were prepared using a facile one-pot hydrothermal method. The SEM and TEM images showed that titanium dioxide and flaky graphene were tightly bound together, and XPS indicated that yttrium was doped uniformly into the complex. The crystal phase of titanium dioxide in Y-TiO2/graphene composite was anatase, and the yttrium doping caused distortion of the titanium dioxide lattice, resulting in a new valence type and more defects. An appropriate amount of yttrium doping and graphene modification significantly improved the separation of photogenerated electron-hole pairs. In the degradation of rhodamine B, the co-modification of yttrium and graphene effectively improved the photocatalytic activity under visible and UV–vis light irradiation. With the amount of yttrium increasing, the photocatalytic activity of the Y-TiO2/graphene complex first increased and reached the highest level of 40% and 63% for visible and ultraviolet-visible light, respectively, when the ratio of yttrium was increased to 1.0%. The enhancement of photocatalytic activity can be explained by the presence of yttrium ions increased the visible light absorption of titanium dioxide. Besides, the synergistic effect between yttrium ions and graphene effectively improved the separation rate of photoinduced electron-hole pairs. 相似文献