经典阻尼系统响应求解的分离变换辛解法

阐明经典阻尼系统响应直接辛解法的困难所在,提出一种将经典阻尼系统分离为等价的无阻尼系统,以用辛解法求解经典阻尼系统响应的方法,进一步对无阻尼系统的辛解法进行详细分析.数值算例的结果表明,所提方法有效、可行.     

“轴线”的嬗变 法国现代园林景观对古典主义园林的传承与发展

法国现代园林景观对古典主义园林优秀设计手法的传承与发展涉及到诸多的层面。以＂轴线＂这一法国古典主义园林最典型的设计语言作为主题,从集中性空间、整体性设计以及透视学原理三个层面简要分析古典主义园林轴线景观的典型特征。在此基础上,详细阐释法国现代园林景观对＂轴线＂这一设计手法的传承与发展。无论是空间结构的延续、空间拓展的意识转变还是集中性空间的重组,＂轴线＂仅仅是一种媒介,旨在引出对地域性景观更深层次的精神传承的思索。     

我国“资源诅咒”问题的社会学解析

有关自然资源与经济增长之间的关系一直是学术界及相关人员关注的热点问题之一,“资源诅咒”问题不无例外的涵盖于其中。我国从2005年开始研究“资源诅咒”问题,就目前情况而言,多数研究停留于经济学层面,从社会学范畴对该问题进行讨论的作品鲜见,本文则在此方面做了有益尝试。从经济学对我国“资源诅咒”问题的分析着手,通过追溯其理论渊源及回溯其经济学分析,引出社会学视角,分别从人口产业结构固化、贫困文化与文化堕距、社会分化下的垂直性差异和输入型阻滞4个维度对相关问题进行剖析,提出相应的对策,以期对现有研究进行补充,同时给相关的实务领域和社会发展带来一些启发。     

Implementation of classical nucleation and growth theories for precipitation

Three ways of implementing classical nucleation and growth theories for precipitation are presented and discussed: (i) the “mean radius approach” (particle size distribution is restricted to its mean radius and density); (ii) the “Euler-like multi-class approach” (the particle size distribution is discretized in several size classes and its time evolution is calculated evaluating the fluxes between neighboring classes); and (iii) the “Lagrange-like multi-class approach” (the particle size distribution is again discretized in several size classes, whose radius time evolution are calculated). In some simple cases, the three approaches lead to similar results, but when more complex heat treatments are involved, multi-class approaches are required. Although the Euler-like approach involves a more complex class number management, it is more adapted to the modeling of precipitate chemistry. Some examples of implementation are presented: Cu precipitation in ferrite, Al₃Sc precipitation in aluminum, VC and NbVC precipitation in austenite.     

Selective atomic hydrogen heating in plasmas: Implications for quantum theory

A new model of quantum mechanics, Classical Quantum Mechanics, is based on the (nearly heretical) postulate that electrons are physical objects that obey classical physical laws. Indeed, ionization energies, excitation energies, etc. are computed based on picturing electrons as ‘bubbles’ of charge that symmetrically surround a nucleus. Hence, for example, simple algebraic expressions based on Newtonian force balances are used to predict ionization energies and stable excitation states with remarkable precision. One of the most startling predictions of the model is that there are stable ‘sizes’ of the hydrogen atom electron (bubble diameter) that are smaller (‘hydrinos') than that calculated for the ‘ground state’. Experimental evidence in support of this novel physical/classical version of quantum is alleged to be found in the existence of super-heated hydrogen atoms reported by many teams in a variety of plasmas. It is postulated that the energy required for creating super-heated H atoms comes from the shrinkage of ground state H atoms to form hydrinos. This claim is discussed with reference to a brief review of the published studies of selective Balmer series line broadening in pure H₂ and mixed gas plasmas, and astrophysical data.     

课程社会学基础研究述评

课程社会学基础的研究,内容包括课程研究的社会学范式,课程的社会学分析,教育社会学流派对课程的透析等。文章分析了各种理论流派的得与失,指出了今后课程理论研究的方向。     

“内部工程社会学”与“外部工程社会学”——建构工程社会学体系的一种尝试

目前工程社会学在我国正逐渐兴起,出现了"工程共同体论"、"社会评价论"和"建设工程系统论"三种不同研究范式,各学者对系统的工程社会学体系莫衷一是。本文首先批判性梳理了上述三种范式,指出其对于工程社会学建构的作用和意义;其次,借鉴英国科学社会学家约翰·齐曼对科学社会学知识的类型划分,将工程社会学体系划分为"内部工程社会学"和"外部工程社会学",并提出"工程域"和"工程社区"两个概念,它们是工程社会学的基本范畴,也分别是内部工程社会学和外部工程社会学的核心概念;最后,展望工程社会学发展前景,指出工程社会学必将成为社会学"学术大家庭"中的重要一员。     

Curvature effects on electric-double-layer capacitance

Understanding the microscopic structure and thermodynamic properties of electrode/electrolyte interfaces is central to the rational design of electric-double-layer capacitors (EDLCs). Whereas practical applications often entail electrodes with complicated pore structures, theoretical studies are mostly restricted to EDLCs of simple geometry such as planar or slit pores ignoring the curvature effects of the electrode surface. Significant gaps exist regarding the EDLC performance and the interfacial structure. Herein the classical density functional theory (CDFT) is used to study the capacitance and interfacial behavior of spherical electric double layers within a coarse-grained model. The capacitive performance is associated with electrode curvature, surface potential, and electrolyte concentration and can be correlated with a regression-tree (RT) model. The combination of CDFT with machine-learning methods provides a promising quantitative framework useful for the computational screening of porous electrodes and novel electrolytes.     

A changing society and problems of method: a politically committed research type

This essay examines a politically engaged research genre, which follows the biography of the author who founded two journals: one on mathematical models published in English (Quality and Quantity) and one on politically committed social and economic research published in Italian (Inchiesta). The research considered focuses on Italy in the 1950s, the research by Lazarsfeld in Vienna in the 1920s and in the United States in the 1950s and 1960s, and post-1968 politically committed research in Italy. The analysis of such politically committed types of research (all very different from one another in terms of the interpretative model of reality, the methods used and the relations with the tendering party and the people observed) allows one to understand how this kind of research can be performed with very different methods—all of which do, however, seek to modify reality on the grounds of the research results. The metaphor of the crystal and the flame presented by Italo Calvino in order to classify facts and ideas and styles and feelings can also be used to visualise the polarity (and the difficulty/impossibility of contact) that has always been present in sociology between two different tendencies: towards a discipline that offers the most abstract and objective interpretative model of reality possible with the use of mathematical models (the crystal), and, instead, towards a discipline in which an interpretative model of reality is central, one that produces a social change and in which the qualitative and quantitative methods utilised are at the service of this change (the flame). This polarity thus allows us to separate first and foremost all the politically committed research performed by others for different purposes (market research, research to verify some theoretical hypotheses, etc.) but the same polarity also lies within the politically committed research. We can, indeed, identify a type of politically committed research in an area that has, at one extreme, research tending towards the utmost objectivity and scientific quality of the results and where the co-ordinators try to have all the information on the subjects maintaining the greatest possible distance (the subjects must not know they are being observed); at the other extreme, there is a type of research in which the coordinator completely involves the subjects in the gathering of information that will serve to realise a piece of research whose political aims are explicitly shared. For the identification of a sufficiently articulated typology it has been important to consider five dimensions of politically committed research: (a) the characteristics of the research coordinator (his/her belonging to the type and the academic/non-academic professional status) and his/her interpretative model of reality (b) some general characteristics of the research (the tender and funding, the topic choice, the aims, the contributions to the sociological theory, the duration); (c) the research coordinators relations with the political actors (the intensity of the relations, the political use of the research); (d) the relations of the research co-ordinator with the research subjects; (e) the methodological choices (the basic strategies, the methods used, the use of mathematical procedures). The research that exemplifies this typology is all politically committed to the left and was realised in different times and contexts. I start by considering a kind of politically engaged research (co-research) that appeared in Italy in the 1950s; I then analyse two types of politically engaged research realised in Austria at the end of the 1920s and one in the United States in the 1950s; there then follow two kinds of research realised in the 1960s and 1970s in the United States and a further two kinds realised in Italy in the 1970s and early 1980s. In order to have other kinds of research please refer to the two Journals of which I am the editor: one is an English language journal of mathematical models (Quality and Quantity, International Journal of Methodology, founded in 1966 and published today by Kluwer of Amsterdam), and a politically engaged review (Inchiesta, founded in 1971 and still published today by Dedalo of Bari).     

Subharmonic Resonance Behavior for the Classical Hydrogen Atomic System

Previously unexplored resonance conditions are shown to exist for the classical hydrogen atomic system, where the electron is treated as a classical charged point particle following the nonrelativistic Lorentz-Dirac equation of motion about a stationary nucleus of opposite charge. For circularly polarized (CP) light directed normal to the orbit, very pronounced subharmonic resonance behavior is shown to occur with a variety of interesting properties. In particular, only if the amplitude of the CP light exceeds a critical value, will the resonance continue without radius and energy decay. A perturbation analysis is carried out to illustrate the main features of the behavior. The present phenomena adds to a growing list of other nonlinear dynamical behaviors of this simple system, that may well be important for more deeply understanding classical and quantum connections.