求解整数的任意次方根的一种算法设计及代码实现

文章介绍了一种利用多项式公式,推导出一种仅使用加法求整数的任意次方根的算法及代码实现,并对此算法时间复杂度进行了分析.     

Serendipity: Towards a taxonomy and a theory

Serendipity, the notion of researchers making unexpected and beneficial discoveries, has played an important role in debates about the feasibility and desirability of targeting public R&D investments. The purpose of this paper is to show that serendipity can come in different forms and come about in a variety of ways. The archives of Robert K Merton, who introduced the term to the social sciences, were used as a starting point for gathering literature and examples. I identify four types of serendipity (Walpolian, Mertonian, Bushian, Stephanian) together with four mechanisms of serendipity (Theory-led, Observer-led, Error-borne, Network-emergent). I also discuss implications of the different types and mechanisms for theory and policy.     

植物学家和人文主义者胡先骕

本文概述了植物分类学家胡先骕在发现植物新种水杉中的贡献;他在上世纪五十年代批判李森科,倡导摩尔根遗传学说的动因,及其科学、人文背景;最后,作为新文化运动中《学衡》派主力和唯一的科学家,本文对他的新人文主义思想做一简介和评述。     

Discrete-time modeling and control of a boost converter by means of a variational integrator and sliding modes

This work deals with the discrete-time modeling of a boost DC-to-DC power converter by means of a discrete Lagrangian formulation based on the midpoint rule integration method. Then in the basis of this model, a discrete-time sliding mode regulator is designed in order to force the boost circuit to track a DC-biased sinusoidal signal. Simulations and experimental tests are carried on where the great performance of the proposed methodology is verified.     

Sectoral patterns of technical change: Towards a taxonomy and a theory

The purpose of the paper is to describe and explain sectoral patterns of technical change as revealed by data on about 2000 significant innovations in Britain since 1945. Most technological knowledge turns out not to be “information” that is generally applicable and easily reproducible, but specific to firms and applications, cumulative in development and varied amongst sectors in source and direction. Innovating firms principally in electronics and chemicals, are relatively big, and they develop innovations over a wide range of specific product groups within their principal sector, but relatively few outside. Firms principally in mechanical and instrument engineering are relatively small and specialised, and they exist in symbiosis with large firms, in scale intensive sectors like metal manufacture and vehicles, who make a significant contribution to their own process technology. In textile firms, on the other hand. most process innovations come from suppliers.These characteristics and variations can be classified in a three part taxonomy based on firms: (1) supplier dominated; (2) production intensive; (3) science based. They can be explained by sources of technology, requirements of users, and possibilities for appropriation. This explanation has implications for our understanding of the sources and directions of technical change, firms' diversification behaviour, the dynamic relationship between technology and industrial structure, and the formation of technological skills and advantages at the level of the firm. the region and the country.     

Bending-torsional flutter of a cantilevered wing containing a tip mass and subjected to a transverse follower force

This paper is a study of the bending-torsional flutter of a cantilevered wing subjected to a follower force, and containing a lumped mass, at the free end. In addition, a distributed aerodynamic loading is introduced along the wing. This results in a set of nonself-adjoint differential equations with variable, complex coefficients whose solutions are obtainable only in series form. Using the Frobenius method, a direct procedure is employed which retains the exact expression of the Theodorsen function and the unknown coefficients are evaluated on a computer which numerically converge to any prescribed accuracy. It is found that, as a result of the interaction of the two sources of non-conservative loadings, the follower force reduces considerably the critical speed of flows in all cases studied. An increase in the tip mass, however, has a stabilizing influence. The effect of structural damping is also examined and it is shown that internal damping forces may have pronounced influences on the flutter speed of the system.     

Employee relationship and knowledge sharing: a case study of a Taiwanese finance and securities firm

Knowledge Management Research & Practice - Knowledge is a very important resource for preserving valuable heritage, learning new things, solving problems, creating core competences, and...     

企业对内外部信息的通透性模型研究

为讨论信息对企业的作用及企业的信息处理能力，本文首先推导在信息绝对平衡状态下的信息效应指数公式，进而综合考虑自然扩散和准强制性推广两种因素，推导出非平衡的稳态即恒定激励状态下的信息流公式。通过对上述两个公式的分析，归纳企业在两种状态下对内外部信息通透性的特点。     

抓好一项活动 培育一种品质 成就一生精彩

我们学校全体师生齐心协力,锐意进取,从学生最喜欢的活动抓起,从教育最基本的积累开始,关注细节,培育做人做事的品质,努力为学生的一生精彩奠基,取得了积极的成效。     

技术本质的隐喻理解及其微观解释

隐喻方法的重要性使我们想到以隐喻的独特视角来观察已有的技术本质研究。采用隐喻方式来解读技术的本质普遍存在于技术哲学研究之中。技术本质的隐喻理解给我们提供了探讨技术本质的广阔的语境。“过程论”的技术本质研究表现为一种理性隐喻方法 ,沿着这种方法所指出的路径 ,我们有可能深化对于技术本质的理解。由对于生产过程的技术现象的宏观分析转入消费和商品审美过程的技术现象的微观分析 ,使我们给出了技术本质的微观解释。     

一种多适性垃圾桶的设计与实现

一种多适性垃圾桶设计摒弃以往传统垃圾桶的形象,使垃圾桶具有更好的适应性,其设计理念来源于生活中一次性塑料购物袋的再次利用。通常我们生活中的废弃购物袋大小不一,垃圾桶确是有固定规格,无法满足各种袋子套置的要求,尤其是过小的袋子,人们想再次利用却有心无力,该方案的设计从改变垃圾桶的形态做起,上下多层的锯齿结构既可牢牢挂住袋子,又可适应不同的袋子,开口更大便于投放垃圾。     

科技查新预检索及医学实例分析

科技查新是我国科技创新服务工作的一个重要环节,科技查新预检索对作好科技查新工作至关重要。笔者探讨了科技查新预检索数据库选择、预检索方法、预检索结果处理等,并就两种主题概念检索方法(主题词检索和关键词检索)举例,进行比较分析。     

金属与非金属蓄冷器交变流动阻力特性对比实验

研究了2种不同填料蓄冷器的内部交变流动阻力特性.建立了在高频条件下测量蓄冷器两端交变流动参数的实验装置,用热线风速仪测量动态流速,由精密压力传感器测量瞬态压力.实验中测量了2台几何尺寸完全相同的蓄冷器,分别填充不锈钢丝网和尼龙丝网.对比实验结果发现,在高频交变流动条件下,不锈钢蓄冷器的周期平均压力降是相同雷诺数下稳定流动压力降的1 2～2倍.这一结果与其他相关文献的结论基本吻合.对于非金属蓄冷器,发现它的平均压降要大于金属蓄冷器的平均压降,是相同条件下稳定流动的3～5倍.这一结果对于高频无磁脉冲管制冷机的设计和机理理解是有意义的.     

Relations between the shape of a size-frequency distribution and the shape of a rank-frequency distribution

We study the dependence of the shape of the rank-frequency distribution g on the shape of the size-frequency distribution f and vice versa. We show mathematically that g is convexly decreasing if and only if f is monotonically decreasing and that g has an S-shape (i.e., g is first convexly decreasing and then concavely decreasing) if and only if f is first increasing and then decreasing.     

Production of microbial protein: a study of the development and introduction of a new technology

Previous work had indicated a lack of studies assessing ecological and social effects of specific technologies. Production of microbial protein was selected for its definability and because UK products were about to be introduced (1976). The study was conducted by investigation of UK Patent Office records, by literature search and by interviews with researchers, producers, feed-for-mulators and farmers. It was found that research had been stimulated by FAO calls for production of unconventional protein for human food, but that the animal feed market proved the most attractive target, partly because of safety regulatins. Microbial protein can be grown on many organic materials, so there are considerable passibilities for utilising waste products, especially from agricultural activities and from food and drink industries. Nevetheless, the major developments have in fact used petrochemical feedstocks, methane, methanol and ‘n’ alkanes because of their availability in large volume at consistent quality. ICI's ‘Pruteen’ Methylopphilus methylotrophus, grown on methanol is the only product available in large ammounts in the UK, but recent increases in oil prices may alter the economics of this process and may also favour utilisation of waste streams, espicially if water authorities continue to tighten-up discharge reqiurements.The employment implications were not explored, sine they seem likely to be negligible, unless soya were superceded, which is even more unlikely. Utilisation of organic, which is even more unlikely. Utilisation of organic waste streams would have pronounced beneficial effects on ambient water quality.]Developing countries with long peroid of sunlight and sufficient water to produce luxuriant vegetation could utilise crop wastes as a basis for protein production, either as a main objective, or as a co-product with chemical fertilisers intermediates of liquid fuel.     

科学朝代的兴衰 哈佛一个系科的教训

回顾科学史上一个学科、一个系科、一个团队的兴衰,不仅有趣、也引人思考：未来的发展可以得到哪些经验教训？     

Construction and operation of a microrobot based on magnetotactic bacteria in a microfluidic chip

Magnetotactic bacteria (MTB) are capable of swimming along magnetic field lines. This unique feature renders them suitable in the development of magnetic-guided, auto-propelled microrobots to serve in target molecule separation and detection, drug delivery, or target cell screening in a microfluidic chip. The biotechnology to couple these bacteria with functional loads to form microrobots is the critical point in its application. Although an immunoreaction approach to attach functional loads to intact MTB was suggested, details on its realization were hardly mentioned. In the current paper, MTB-microrobots were constructed by attaching 2 μm diameter microbeads to marine magnetotactic ovoid MO-1 cells through immunoreactions. These microrobots were controlled using a special control and tracking system. Experimental results prove that the attachment efficiency can be improved to ∼30% via an immunoreaction. The motility of the bacteria attached with different number of loads was also assessed. The results show that MTB can transport one load at a velocity of ∼21 μm/s and still move and survive for over 30 min. The control and tracking system is fully capable of directing and monitoring the movement of the MTB-microrobots. The rotating magnetic fields can stop the microrobots by trapping them as they swim within a circular field with a controllable size. The system has potential use in chemical analyses and medical diagnoses using biochips as well as in nano/microscale transport.