THE DUTCH INVENTION OF THE ROTOR MACHINE, 1915–1923

The rotor machine was invented in 1915 by two Dutch navy officers, R. P. C. Spengler and Th. van Hengel, who were working at the Navy Department in the Dutch East Indies. A prototype was built by W. K. Maurits, a mechanical engineer, and tested during the summer of that year on board the flagship of the Dutch Navy in the East Indies on order of the fleet commander Rear Admiral F. Bauduin. Though the Dutch Navy decided not to adopt the device for it prevented the invention from being patented by the original inventors. The Navy could not prevent the rotor machine from being patented, however, by Hugo Alexander Koch—an engineer and businessman working in close collaboration with Arthur Scherbius in Germany—who probably became familiar with the idea through his brother-in-law, Huybrecht Verhagen, a patent attorney working at the firm that had supported the abortive patent application by the original inventors.     

THE DEVELOPMENT OF AERONAUTICAL SATELLITE COMMUNICATIONS (Ⅰ)

This paper presents an overview of the development of aeronautical satellite communi-cations over the past 30 years. The initial development of aeronautical satellite communications is de-scribed in the paper. The civil aviation growth and current unaccommodated communication systemsare discussed as well. The inherent shortcomings of present air-ground HF communications have hin-dered the development of civil aviation. but according to the Future Air Navigation Systems(FANS) concept aeronautical satellite communication-including Automatic Dependent Surveillance(ADS)-will be the key to eliminating the shortcomings of HF communication systems. Satellite-basedcommunication and surveillance will significantly improve air traffic control (ATC) over the oceanicand remote terrestrial airspace, and it will benefit civil aviation authorities, airlines as wel as passen-gers. This paper discusses the availability of system elements, and world wide trials, demonstrtionsand preoperational use of aeronautical satelli     

SEMANTICS OF COMPLEX STRUCTURAL SYSTEMS—PRESENTATION AND REPRESENTATION: A SYNCHRONIC VISION OF LANGUAGE L( M T )

Abstract

In this paper, the authors continue developing a Linguistic Theory of the Complex Structural Models, but in terms of the Semantics. Each symbol (transformed function) is syntactically a lexeme, carrying associate a sememe or atomic semantic unit. Each sememe can be decomposed in semes or quantic semantic unities. They are studied the semantic systems, associated with the syntactic, and that serve them as suprastruc-ture, in terms of two levels: the quantic and the atomic. Also, it is demonstrated that for all model of the complex reality, will exist always a most complex model from the syntactic and semantic point of view.     

血海与黑潮(下)——《魔兽争霸Ⅱ》(WARCRAFTⅡ:TIDES OF DARKNESS)完全篇

《魔兽争霸王Ⅱ》是款非常经典的即时战斗游戏,虽然和《终极动员令》(又名《征服与毁灭》)相比各有所长,但《电脑》杂志至今并没有关于这款游戏的详细介绍和攻略,所以这篇文章可算是弥补这份遗憾.     

Interdiffusion and atomic mobilities in bcc V–X (X = Mn,Sn and Ni) alloys: Measurement and modeling

Totally 8 diffusion couples were prepared and the composition-dependent interdiffusion coefficients in bcc V–Mn, V–Sn and V–Ni alloys were measured between 1323 and 1503 K by means of Sauer-Freise method coupled with electronic probe microanalysis (EPMA) technique. The errors of the interdiffusion coefficients were computed by error propagation method. Based on the measured interdiffusivities and thermodynamic parameters from the literature, the atomic mobilities of bcc V–X (X = Mn, Sn and Ni) alloys were obtained by using the CALTPP (CALculation of ThermoPhysical Properties) program with the features of high efficiency and accuracy in the framework of CALPHAD (CALculation of PHAse Diagram) approach. For each system, the presently obtained atomic mobilities were validated by good agreement between the calculated interdiffusivities and the measured ones. The model-predicted concentration profiles in this work are consistent with the experimental ones. This work contributes to the establishment of the atomic mobility database containing V element and the key input for microstructure simulations in V-based alloys.     

Thermodynamic properties of sodium pyrovanadate (Na4V2O7) at high temperature (298.15–873 K)

The sodium pyrovanadate (Na₄V₂O₇) powder was synthesized by solid-state reaction using sodium carbonate (Na₂CO₃) and vanadium pentoxide (V₂O₅) as raw materials. X-ray powder diffraction (XRD), scanning electron microscope (SEM), and differential scanning calorimeter (DSC) were used to accurately characterize the synthesized sample. The solid-state phase transformation from α-Na₄V₂O₇ to β-Na₄V₂O₇ occurs at the temperature 696 K and the enthalpy is equals to 1.03 ± 0.01 kJ/mol, the endothermic effect at 931 K and the enthalpy is equals to 31.35 ± 0.31 kJ/mol, which is related to the melting of Na₄V₂O₇. The high-temperature heat capacity of Na₄V₂O₇ was measured using a Multi-high temperature calorimeter 96 line and DSC. The obtained high-temperature heat capacity of Na₄V₂O₇, as a function of temperature, was modeled as: Cp=314.62+0.05T-5494390T^-2 J·mol^-1·K^-1 (298.15-873 K). The temperature dependence on heat capacity was then used for computing changes in the enthalpy, entropy, and Gibbs free energy at the specific temperature internal.     

DNA计算机原理、进展及难点(V):DNA分子的固定技术

在DNA计算机的研制中,DNA分子的固定是首先需要处理的一个最为基本的技术问题.事实上,DNA分子的固定技术不仅是生物计算的一个基本技术,而且是整个基因工程、生物芯片,甚至某些疾病诊疗的基础.基于此,文中将对DNA分子的固定技术给予较为系统的研讨,包括基本原理、具体方法等.文中引入了"DNA分子固定系统"的结构体系,并对该结构体系中载体子系统、固定剂子系统、标记子系统这3个主要子系统进行了详细的论述.     

Educational virtual environments: A ten-year review of empirical research (1999–2009)

This study is a ten-year critical review of empirical research on the educational applications of Virtual Reality (VR). Results show that although the majority of the 53 reviewed articles refer to science and mathematics, researchers from social sciences also seem to appreciate the educational value of VR and incorporate their learning goals in Educational Virtual Environments (EVEs). Although VR supports multisensory interaction channels, visual representations predominate. Few are the studies that incorporate intuitive interactivity, indicating a research trend in this direction. Few are the settings that use immersive EVEs reporting positive results on users’ attitudes and learning outcomes, indicating that there is a need for further research on the capabilities of such systems. Features of VR that contribute to learning such as first order experiences, natural semantics, size, transduction, reification, autonomy and presence are exploited according to the educational context and content. Presence seems to play an important role in learning and it is a subject needing further and intensive studies. Constructivism seems to be the theoretical model the majority of the EVEs are based on. The studies present real world, authentic tasks that enable context and content dependent knowledge construction. They also provide multiple representations of reality by representing the natural complexity of the world. Findings show that collaboration and social negotiation are not only limited to the participants of an EVE, but exist between participants and avatars, offering a new dimension to computer assisted learning. Little can yet be concluded regarding the retention of the knowledge acquired in EVEs. Longitudinal studies are necessary, and we believe that the main outcome of this study is the future research perspectives it brings to light.