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1.
This essay proposes a new notion - the landing zone - in order to identify conceptual features that allow modelers to transfer mathematical tools across disciplinary borders. This discussion refers to the transferable models as ‘templates’. Templates are functions, equations, or computational methods that are capable of being generalized from a particular subject matter. There are formal and conceptual prerequisites for the transfer of a template to a new domain. A landing zone is an ontology that contributes to the satisfaction of these conditions for successful transfer. This paper presents a case study on a model in chemistry - the Quantum Theory of Atoms in Molecules (QTAIM) - that makes use of transferred templates from physics - the virial theorem and the wave function. The landing zone in this case is a new ontological notion, that of the topological atom, which prepares ground for the use of the virial theorem and the wave function in chemistry. The virial theorem requires that there exists in-principle stability to the system that it represents, and the wave function requires transformation in its representation that is justified. The ontology of QTAIM - the landing zone for these templates - grounds the scientific use of these templates in the context of chemistry.  相似文献   
2.
In this paper I consider the structures that chemists and physicists attribute at the molecular scale to substances and materials of various kinds, and how they relate to structures and processes at other scales. I argue that the structure of a substance is the set of properties and relations which are preserved across all the conditions in which it can be said to exist. In short, structure is abstraction. On the basis of this view, and using concrete examples, I argue that structures, and therefore the chemical substances and other materials to which they are essential, are emergent. Firstly, structures themselves are scale-dependent because they can only exist within certain physical conditions, and a single substance may have different structures at different scales (of length, time and energy). Secondly, the distinctness of both substances and structures is a scale-dependent relationship: above a certain point, two distinct possibilities may become one. Thirdly, the necessary conditions for composition, for both substances and molecular species, are scale-dependent. To know whether a group of nuclei and electrons form a molecule it is not enough to consider energy alone: one also has to know about their environment and the lifetime over which the group robustly hangs together.  相似文献   
3.
本文主要目的是拓展基于区间解析冗余关系法I-ARRs(Interval valued Analytical Redundancy Relations)对不确定性混杂系统的故障检测。该方法产生一组对故障估计的阈值,一旦标称残差超过阈值,则故障能被检测。现有的故障检测方法主要是针对参数性故障,因此对测量信号导数的估计呈现出各种限制。而且在I-ARRs中对测量信号导数十分敏感,这不可避免地涉及到对残差的估计。为解决这一问题,利用鲁棒滑模微分器方法得到对含噪声测量信号导数最优估计,降低残差噪声,以减小虚警、漏报,从而提高鲁棒性。通过典型电力电子电路BUCK电路仿真,验证了此方法的有效性。  相似文献   
4.
ABSTRACT

From 1797 to 1801 a controversy played out on the pages of the Medical Repository, the first scientific journal published in the United States. At its centre was the well-known feud between the followers of Antoine Lavoisier and Joseph Priestley, the lone supporter of the phlogiston model. The American debate, however, had more than two sides. The Americans chemists, Samuel Latham Mitchill and Benjamin Woodhouse, who rushed to support Priestley did not defend his scientific views. Rather, as citizens of a republic, they defended his right to have them. They also castigated the assertions of the “French chemists,” whose claims that the new chemistry obviated debate seemed unsettlingly similar to the dictatorial ambitions of the French state. Using the Medical Repository, Mitchill and Woodhouse sought a compromise that validated the new chemistry, but united it with a more egalitarian form of discourse. The desired balance eluded them. Priestley proved too stubborn, and as the French Revolution descended into dictatorship and war, Mitchill and Woodhouse came more to realize that truly prising French chemistry from the culture of the revolutionary era. The episode left Mitchill and Woodhouse disillusioned with chemistry and hoping to redirect scientific enthusiasm to more pious ends.  相似文献   
5.
本文研究了周期调制噪声和非对称双态噪声联合驱动下具有频率涨落的谐振子的随机共振现象,本文的主要工作是通过Shapiro-Logniov公式求解了谐振子系统的稳态响应一阶矩的解析表达式,并且推到了谐振子系统的稳态响应一阶矩的稳定性条件。最后发现了系统关于不同参数的广义随机共振现象,出现了双峰共振现象等丰富的动力学行为。  相似文献   
6.
天然药物化学是高等医学院校药学专业的一门必修课,在教学中结合天然药物化学的课程特点,通过介绍天然药物发展史、改变教学模式、介绍新成果等方式,加强天然药物化学的理论教学,培养学生的创造性思维。  相似文献   
7.
本文探讨了自然科学复杂问题研究中的解析法、实验法和仿真法各自不同的内涵和思维活动特征,论述了三种研究方法的特点、作用、地位和相互之间的关系。以风力机气动设计为例,重点论述了解析法的研究步骤,对研究过程中出现的本质与现象、对立与统一、主要矛盾与次要矛盾、复杂与简化、局部与整体等辩证法范畴的问题进行了分析。  相似文献   
8.
根据《大学化学》课程的特点,从问题引导、激发兴趣、发挥想象和实践教学等方面,阐述在《大学化学》教学过程中如何培养学生的创新思维和创新能力,提高教学质量.  相似文献   
9.
创新能力的培养是当今科技迅速发展对研究性教育提出的必然要求,传统的重理论、重传授、忽视个性发展的教学思想严重阻碍了创新人才的培养.针对本校的专业特点,提出基于创新人才培养的教学改革措施:转换教师-学生教学模式、教师交叉知识体系的更新、课程体系的不断优化、创新型实验的开设、精英教育与大众教育并重等.激发了学生的学习热情,增强了学生的创新能力、积极推进了学生实践能力的提高.  相似文献   
10.
创新性化学人才培养中的探究性实验教学研究与思考   总被引:1,自引:0,他引:1  
在高等教育深化改革的形势下,通过分析国内外化学实验的教学现状,对高校化学专业的探究性实验教学进行了思考与探索。  相似文献   
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