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21.
基于MSP430F449单片机的24BYJ48步进电机控制 总被引:1,自引:0,他引:1
该文介绍了步进电机工作原理,结合MSP430F449单片机,给出MSP430F449单片机的24BYJ48步进电机控制的接口电路及程序实现。文章介绍的硬件和软件均经过实践检验,结构简单,使用方便。 相似文献
22.
介绍了汽车车身集中控制系统的硬件和软件设计,以PIC16F74单片机为控制器,对工作状态信息进行检测,读取测速脉冲数,根据需要满足的功能进行运算处理,发出的相应控制信号经驱动和放大电路来控制门锁、闪光器、蜂鸣报警器等电器元件.将分散的控制功能进行集中整合和扩展,使所有功能在一块单片机上进行控制.整个系统体积小、重量轻、功能完备. 相似文献
23.
[目的/意义]互联网时代出现看多种新论文发表系统,对多种论文发表系统之间逻辑分类关系以及彼此之间的中长期格局演化进行讨论。[方法/过程]从论文发表系统对一篇论文是否进行评议、评议是否分级、是否拒稿3个维度提出论文交流系统分类框架,将期刊、预印本、F1000 Research、在线评级平台4种论文发表系统全部统一在一个分类框架中。另外,基于研究者与研究管理部门对论文交流系统的不同需求,定性分析了论文交流系统的中长期演化格局。[结果/结论]中长期看,在线评级平台将对期刊系统形成明显冲击,期刊内部两极分化。 相似文献
24.
Khalid A. Sindawi 《Al-Masaq: Islam & the Medieval Mediterranean》2009,21(3):269-287
The purpose of the present study is to analyse the role played by an important female figure in early Shī?ite history. The person in question is Fi[ddot][ddot]a l-Nūbiyya, the servant-girl of Fā ?ima, the Prophet's daughter. After a long period of neglect by scholars, who have focused on what to their mind were figures of greater import, we shall here attempt to describe the role played by Fi[ddot][ddot]a in early Shī?ite history by way of analysing her biography and her close relations with Fā ?ima and members of the latter's family (?Alī, [Hdot]asan and [Hdot]usayn). We shall further describe what has been reported of Fi[ddot][ddot]a's personality, her family, her admiration for the Prophet's family, Qur?ānic verses which supposedly mention her, and the great respect in which she was held by Fā ?ima's family. 相似文献
25.
Naoya Todo 《Structural equation modeling》2016,23(5):695-712
In longitudinal design, investigating interindividual differences of intraindividual changes enables researchers to better understand the potential variety of development and growth. Although latent growth curve mixture models have been widely used, unstructured finite mixture models (uFMMs) are also useful as a preliminary tool and are expected to be more robust in identifying classes under the influence of possible model misspecifications, which are very common in actual practice. In this study, large-scale simulations were performed in which various normal uFMMs and nonnormal uFMMs were fit to evaluate their utility and the performance of each model selection procedure for estimating the number of classes in longitudinal designs. Results show that normal uFMMs assuming invariance of variance–covariance structures among classes perform better on average. Among model selection procedures, the Calinski–Harabasz statistic, which has a nonparametric nature, performed better on average than information criteria, including the Bayesian information criterion. 相似文献
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Kinship,Camaraderie and Contestation: Fāṭimid Relations with the Ashrāf in the Fourth/Tenth Century.
Shainool Jiwa 《Al-Masaq: Islam & the Medieval Mediterranean》2016,28(3):242-264
The founding of the Fā?imid caliphate across the southern Mediterranean, and then in Egypt, Syria and the ?ijāz at the turn of the fourth/tenth century, necessitated its negotiation with the ashrāf, those who claimed lineal descent from the Prophet Mu?ammad, and who by this time had gained significant influence as a social class based on their charismatic descent. While other dynastic powers fostered relationships with various members of the ashrāf, the Fā?imid–ashrāf dynamics were distinctive in that the Fā?imids legitimised their rule as Ismā?īlī Shī?ī imām-caliphs, based on their claim of descent from the Prophet Mu?ammad, and as the sole successors to his authority and leadership over the Islamic world. Consequently, Fā?imid–ashrāf relations were permeated by fraternal camaraderie as well as by competing contestations based on their shared claim to Prophetic lineage. 相似文献
29.
Sherif Anwar 《Al-Masaq: Islam & the Medieval Mediterranean》2010,22(3):259-278
The Imam-caliph al-Mu‘izz al-Dīn Allāh undertook a series of monetary changes which were to have a monumental impact on all future Fā?imid coinage, would lead to many imitations even after the dynasty had fallen, and create an easily identifiable pattern that attracted medieval merchants and modern collectors. The fact that al-Mu‘izz's coinage went through three stages with slight variations in the wording and layout indicates that he was determined to create a new model for Fā?imid coinage which would distinguish it from the Aghlabid and ‘Abbāsid coinage that preceded and competed with it. In contrast, Sijilmasa coinage was so conservative in layout due to its role in the African trade. 相似文献
30.
目前在文献中有很多关于多响应比较的研究方法,但是对带协变量调整的非参数检验的研究较少。一种直观的想法是将数据先投影到协变量的正交空间中,然后再利用秩和检验、调整的秩和检验或最大值检验方法。但是,功效普遍不高。在调整的秩和检验和伪F检验两种方法基础上,构建MIN2检验。大量模拟和实际数据表明,MIN2检验的效果优于现有的非参数检验方法。 相似文献