不同数控系统螺纹车削加工的比较

主要对三种不同类型数控系统的螺纹切削加工指令进行比较,找出它们之间的相同点与不同点,可以看出不同系统的指令格式及参数的差异,并举例说明这三种数据系统的指令在实际加工中的应用.     

Unfolding the knowledge and power dynamics of the ‘farmers–rural extensionists’ interface in North-Eastern Argentina

ABSTRACT

Purpose: In this paper, the knowledge dynamics of the farmer–rural extensionist’ interface were explored from extensionists’ perspective with the aim of understanding the matchmaking processes between supply and demand of extension services at the micro-level. Design/methodology/approach: Forty semi-structured interviews were conducted with extensionists whom work in the North-Eastern, Argentine provinces. Findings: Two different, general types of knowledge dynamics were identified: one moderately diffusionist, based on a hierarchical relationship and the prioritisation of experts’ knowledge, and the other constructivist, based on horizontal processes of co-construction. Interestingly, some extensionists support beliefs pertaining to both approaches. They also highlight the importance of unceremonious trainings, interpersonal trust and making recommendations that take into account farmers’ rationale. Practical implications: Results show the persistence of diffusionist rural extension and that extensionists have different, even contradictory, extension approaches, which renders inappropriate any attempt to generalise their perspectives. Theoretical implications: This study suggests that farmers’ demand is the result of a constructive, interactive process, and thus is not prior to the interaction between the demand side (farmers) and the supply side (extensionists). Consequently, the knowledge and power dynamics that take place within the farmer–extensionist interface should be considered the nucleus of demand construction and the matchmaking process. Originality/value: This paper addresses the dynamic matchmaking process between supply and demand of extension services at the micro-level, suggesting it is a constructive process and showing the core role played by power dynamics.     

反非法行政性垄断之对策研究

非法行政性垄断严重破坏了社会主义市场经济秩序，妨碍了公平竞争，在加入WTO后，更应从体制上、立法上进行规制。要建立和完善违宪审查制、司法审查制，尽快出台反垄断法，要从宪法、行政法和经济法上综合整治非法行政性垄断。     

静不定体系的内力分析技术

对于静不定体系，采用以往的分析，计算烦杂，在此本文提出通过广义逆矩阵及奇异分解来实现求解，通过算例表明本文方法简单，准确，易行．可供工程设计参考．     

一类具有非负特征的双曲型方程组的边值问题

研究一类具有非负特征四次型的平面双曲型偏微分方程组,考虑该方程组的与低阶项系数有关的边值问题,获得了关于弱解和古典解的存在唯一件方面的结果.     

一类含离散时滞的细胞动力学模型的渐近性

本文在Martin Eisen的二房室增长模型中引入离散时滞,利用离散时滞稳定性理论,证明了平衡点的渐近稳定性。     

Do flexible admission systems affect student enrollment? Evidence from UK universities

We reveal the current level of flexible admission systems (FAS) at UK universities, and explore its impact on student enrollment rates. We employ quantitative analysis techniques for data collected and customized from the Higher Education Statistics Agency (HESA) in the UK, during the period 2010–2015. To understand the impact of FAS on student enrollment, six statistical tests were conducted. Based on the level of FAS adopted by universities, we identified four groups of UK universities: very low, low, medium, and high levels of FAS. No robust evidence exists to support claims that universities which apply a higher level of FAS have higher student enrollment. The study results were based only on secondary data collected from HESA, so future studies should be based on other types of data. This paper attempts to cover the missing elements of previous literature and its traditional research techniques.     

Is there a role for educational psychologists in facilitating managed moves?

The current research aimed to explore the extent to which school professionals and local authority staff perceived that there was a role for educational psychologists in the processes involved in implementing, monitoring and offering support to young people for whom a managed move was being arranged. The study was conducted in one English local authority where 11 school staff and five local authority staff were interviewed using a thematic analysis methodology. The emerging themes were: lack of role clarity; variability between schools; reactiveness in relation to crisis; capacity; and possibilities for further involvement including transition, preventative work and accurate assessment of needs.     

Delay-dependent robust H∞ control for a class of uncertain switched systems with time delay

For linear switched system with both parameter uncertainties and time delay,a delay-dependent sufficient condition for the existence of a new robust H∞ feedback controller was formulated in nonlinear matrix inequalities solvable by an LMI-based iterative algorithm.Compared with the conventional state-feedback controller,the proposed controller can achieve better robust control performance since the delayed state is utilized as additional feedback information and the parameters of the proposed controllers are changed synchronously with the dynamical characteristic of the system.This design method was also extended to the case where only delayed state is available for the controller.The example of balancing an inverted pendulum on a cart demonstrates the effectiveness and applicability of the proposed design methods.     

A narrative across 28 years in academic development

ABSTRACT

This paper is a narrative across 28 years in academic development. Four phases are described, showing how initially naïve conceptions about academic development have been addressed, enabling a growth towards a more holistic understanding of how diversity, quality assurance, and community networks can productively interface. This narrative will, hopefully, assist reflection by other academic developers.