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排序方式: 共有148条查询结果,搜索用时 78 毫秒
1.
基于PC的开放式数控系统及其在玻璃雕刻机中的应用 总被引:2,自引:2,他引:0
论述了基于PC的开放式数控系统,重点对NC嵌入PC型开放式数控系统应用平台和应用软件的编制进行了研究,解决了构建NC嵌入PC型开放式数控系统的关键问题,并介绍了一个基于PC DMC1000运动控制卡的开放式数控玻璃雕刻机系统的开发实例。 相似文献
2.
《Fuel》2006,85(10-11):1509-1517
FT-IR/Raman spectroscopies have been used to identify the structural features of Victorian brown coal chars during the gasification in air at 400 °C. The deconvolution of the Raman spectra has allowed us to identify the main structural sites in char where preferential reaction with O2 takes place. The presence of Na and Ca catalysts is shown to alter the reaction pathways between char and O2. In the absence of a catalyst, the O-containing functional groups formed in char during gasification were closely associated with the aromatic structure and thus tended to loosen the aromatic structure. The non-catalysed gasification was slow and took place on some specific (especially sp3-rich or sp2–sp3 mixture) sites distributed throughout the char. In the presence of a catalyst (Na or Ca), the O-containing functional groups were not closely associated with the main aromatic structure throughout the char. The catalytic gasification reactions were localised on the sites associated with the catalysts. The preferential removal of smaller aromatic ring systems and the persistence of cross-linking structures in the presence of a catalyst mean that the large aromatic ring systems were increasingly concentrated with little flexibility, affecting the dispersion of catalyst. 相似文献
3.
Min Luo Ji-Qiang Gao Jian-Feng Yang Jun-Zhuo Fang Zheng Wang 《Journal of the American Ceramic Society》2007,90(12):4036-4039
Biomorphic silicon nitride (Si3 N4 ) ceramics with fibrous morphology were fabricated by combining sol–gel infiltration with carbothermal reduction nitridation from wood precursor. Y2 O3 -incorporated silica sol was used as the infiltrated solution to promote the formation of fibrous Si3 N4 grain at 1600°C under high nitrogen pressure (0.6 MPa). The influence of sintering conditions (additive and temperature) on the phase composition and microstructure of sintering bodies was analyzed, and the reaction mechanism is discussed. 相似文献
4.
采用一种结构简单、使用方便灵活、用途广泛的多功能集成电路,即555时基集成电路。设计了家用自动浇花设备,用于实现水泵及电磁阀的开启与关闭自动控制.当土壤中的含水量低于设定值时该系统可进行灌溉,可以根据设计好的土壤湿度分别对多种花卉自动进行浇灌,实现家庭花卉种植自动浇水的功能.该设备具有重量轻,操作简单,使用方便,工作可靠,过载能力强,批量生产成本低,适合家用的特点. 相似文献
5.
《International Journal of Hydrogen Energy》2019,44(12):6036-6044
The graphene nanosheets are synthesized by modified Hummer's method, based on which the dual active metals Ni and Al doped graphene composites are prepared through in-suit reaction and self-assembly with high-temperature reduction process. The molecular structure, morphology and specific surface area of graphene nanosheets are characterized systematically. The phase composition, surface morphology and hydrogen storage properties of dual active metals Ni and Al doped graphene composites are further investigated by X-ray diffraction, scanning electron microscopy and gas reaction controller. Results show that the graphene nanosheets have typical graphene feature, whose transparent graphene edges can be observed clearly, and the specific surface area is as high as 604.2 m2 g−1. The Ni and Al doped graphene composites are composed with Ni, Al and C phases, which have high hydrogen storage capacity and excellent hydriding/dehydriding stabilities. The maximum hydrogen storage uptake of such composites is up to 5.7 wt% at 473 K, and the dehydriding efficiency is high as 96%∼97% at the dehydriding temperature of 380 K. The hydrogen adsorption and desorption rate control step of the Ni and Al doped graphene composites is complied to the nucleation and two-dimensional growth mechanism. 相似文献
6.
《Carbon》2014
Graphene-based materials have been proposed as promising electrodes for electric double layer capacitors. Recently, it has been found that one of the limitations of graphene electrodes is the finite quantum capacitance at low applied voltage. In this work, we investigate the impact of having point-like topological defects in graphene on the electronic structure and quantum capacitance. Our results clearly show that the presence of defects, such as Stone Wales, di-vacancies, and di-interstitials, can substantially enhance the quantum capacitance when compared to pristine graphene, which is found to be due to defect-induced quasi-localized states near the Fermi level. In addition, the charging behavior tends to be asymmetric around the neutrality point. We also discuss the possibility of tuning the electronic structure and capacitance through mixtures of these defects. Our findings suggest that graphene-based electrodes with topological defects may demonstrate noteworthy capacitance but should be carefully selected for use as either the positive or negative electrode. 相似文献
7.
为了深入研究数控系统的开放性和通用性,在分析了开放式数控系统原理的基础上,设计了一种基于"PC 运动控制器"的开放式数控系统实验台.该系统是以Windows XP为开发平台,采用美国CamSoft公司的CNC Professional软件作为数控系统的开发软件、美国Galil公司的DMC-1832型运动控制卡完成实时控制功能的,再加上华中数控实验台本体部分,充分体现了硬件和软件的开放性.研究表明,该设计具有十分人性化和个性化的用户操作界面,是可以取代传统数控系统的开放式数控系统. 相似文献
8.
《International Journal of Hydrogen Energy》2023,48(52):20028-20040
In a worldwide environment context where the emergency need to decrease pollutant emissions is an important issue, the research for solutions is increasing. Fuel cell technology is anticipated to become a practicable approach for solving the problem of pollution due to its environmentally friendly characteristics. In this work, a novel problem formulation is suggested for the efficient recognition of PEMFC parameters which the solving is by using the Improved Fish Migration Optimizer (IFMO) technique. After coding the steps of the algorithm in MATLAB, the objective function is resolved for the fuel cell. Comprehensive simulations evaluate the formulation performance with the suggested and traditional objective functions; then, the outcomes are compared. To confirm the suggested formulation ascendancy compared to the traditional curve-fitting method, a complete assessment based on convergence rate, the value of the objective function, and the value of absolute voltage error are performed. The achieved value of the objective function, absolute voltage error, and average time of computation is 0.005, 0.4, and 1.63, respectively. Environmentally, the combustion of hydrogen and its use in PEMFC produce no carbon dioxide. 相似文献
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