Extinc非自治竞争Lotka- Volterra系统的灭绝性(英文)

研究了几个种群非自治 L otka- Volterra竞争系统 ,给出了竞争的 n个种群中任意 r个持续生存而 n- r个灭绝的一类充分条件     

Non-Existence of Stable Currents in Hypersurfaces

Let M^m be a compact hypersurface in the Euclidean space E^m+1. In this paper, we study the non-existence of stable integral currents in M^m and its immersed submanifolds. Some vanishing theorems concerning the homology groups of these manifolds are established.AMS Subject Classification (1991): 49Q15 53C40 53C20     

A Stochastic Process Generated by the Lévy Laplacian

In this paper we give a stochastic process generated by the Lévy Laplacian in the white noise analysis with a characterization of the Laplacian.     

The Stochastically Subordinated Poisson Normal Process for Modelling Financial Assets

The method of stochastic subordination, or random time indexing, has been recently applied to Wiener process price processes to model financial returns. Previous emphasis in stochastic subordination models has involved explicitly identifying the subordinating process with an observable quantity such as number of trades. In contrast, the approach taken here does not depend on the specific identification of the subordinated time variable, but rather assumes a class of time models and estimates parameters from data. In addition, a simple Markov process is proposed for the characteristic parameter of the subordinating distribution to explain the significant autocorrelation of the squared returns. It is shown, in particular, that the proposed model, while containing only a few more parameters than the commonly used Wiener process models, fits selected financial time series particularly well, characterising the autocorrelation structure and heavy tails, as well as preserving the desirable self-similarity structure, and the existence of risk-neutral measures necessary for objective derivative valuation. Also, it will be shown that the model proposed fits financial times series data better than the popular generalised autoregressive conditional heteroscedasticity (GARCH) models. Additionally, this paper will develop a skew model by replacing the normal variates with Lévy stable variates.     

Current-sensing atomic force microscopy for analyzing conformations and properties of polymer membranes for fuel cells

The three-dimensional structures of polymer membranes are different at surfaces and inside bulks, and thus, in general, physical/chemical properties are also different. Morphologies and properties of membrane surfaces are now visualized by current-sensing atomic force microscopy. The increase in performances of a single cell is discussed based on the three-dimensional structures of the polymer membrane, anion-exchange membrane as an example, used for fuel cells. Other reports on Nafion®, proton-exchange membrane, are also introduced to show the importance of this microscopic method.     

Выделение меченых соединений методом препаративной хроматографии

Mica Track Microfilters (MTM) are successful applied to separate two different and strongly mixed liquid phases (emulsion). The organic and the inorganic phase of the emulsion were 30% tributyl phosphate (TBP) in kerosene and 2 N HNO₃ (or H₂O), respectively. Mica filters with sharp edges (i.e. etched with H₂F₂) and having pore sizes k of 8 μm > k > 2 μm are used to get under some well defined conditions a rather complete extraction of the aqueous phase out of the emulsion. The system was calibrated with the pure phases (water as well as TBP in kerosene), and the liquid throughput is shown as a function of the pore size of the filter. The throughput depends mainly on the pore size and not that much on the kind of liquid, it is slightly larger for water as compared to that of TBP in kerosene.     

如何调控经济金融化？——基于中国经济的三方演化博弈视角

十九大以来,中国的改革开放进程不断加快,在金融领域体制改革也是不断深化,开放程度不断提高,期间实体经济金融化的问题在我国日益凸显,经济“脱实向虚”的现象愈发严重,而实体经济能否健康发展将决定一个国家综合国力的强弱。因此,通过研究实体企业金融化问题来探讨中国防范产业“空心化”的策略非常必要。运用演化博弈和模拟仿真的方法,构建基于政府监管部门、实体企业和金融企业金融化的三方演化博弈分析框架,重点分析政府监管对企业策略选择的影响,并对演化均衡过程进行模拟仿真。研究表明,政府对企业所采取措施譬如加大处罚、提高减税幅度或补贴等对促进实体企业和金融企业达成合作关系有积极作用,实体企业和金融企业对分利技术水平和社会禀赋倍增率的变化敏感。     

Mathematische und Graphische Methoden zur Bewertung des [15N]Methacetin-Testes für die klinische Praxis

Im Zusammenhang mit der Einführung eines nichtinvasiven ¹⁵N-Leberfunktionstests entstand die Notwendigkeit, durch Interpretation der Meßergebnisse bestimmte Kenngrößen zu ermitteln, die eine spezifische Leberfunktion in einem Wert widerspiegeln.

Es wurden drei Auswertemethoden erprobt, ein graphischer Meßwertausgleich, eine Regressionsrechnung unter alleiniger Verwendung der Eliminationsgleichung sowie die Auswertung auf der Grundlage eines Kompartmentmodells, welches Invasion und Elimination des Diagnostikums berücksichtigt. Zur Realisierung der zuletzt genannten Methode wurde das Computerprogramm PATMETH entwickelt. Vergleichende Betrachtungen, die auf der Grundlage der Ergebnisse von 250 ausgewerteten Tests vorgenommen wurden, zeigen die Überlegenheit der computergestützten Auswertemethode. Sie basiert auf einer einheitlichen theoretischen Grundlage, welche Willkür ausschliet, ermöglicht exakte Fehlerangaben der Testparameter und ist wesentlich zeitsparender.

In connection with the introduction of a non-invasive ¹⁵N liver function test the necessity arose to evaluate certain parameters reflecting a specific liver function by interpretation of the measured values.

There were tested three evaluation methods: a graphic fit of measured values, a linear regression by using only the elimination equation and the evaluation on the basis of a compartment model, which is considering invasion and elimination of the diagnostic agent. For realizing the last method there was developed the computer program PATMETH. Comparative investigations based on the evaluation of 250 tests show the superiority of the computer based calculation method. It is founded on a uniform theoretical basis excluding arbitrariness, it permits exact information about the error values of the test parameters and it is substantial time-sparing.