自串联发射卫星平台结构分系统设计与验证

与传统的一箭双星发射模式相比,卫星自串联发射具有更高的载荷比。文章面向支撑自串联一箭双星发射的全电推平台结构分系统研制,分析自串联发射卫星结构分系统的设计要求和特点,并提出适应自串联发射卫星平台的力学试验验证策略,实现了低成本、高效率的金字塔式验证。结果表明,支持自串联双星发射的结构平台成功通过力学环境试验考核,相关设计及试验方法可为同类航天器结构研制提供参考借鉴。

大型通信卫星公用平台结构分系统设计特点

本文针对我国下一代大型通信卫星公用平台新的要求,通过综合总体技术设想,在结构构型、分舱、大型中心承力筒及结构舱板设计、舱段间及板间连接方式等方面对我国未来大型通信卫星公用平台结构分系统的设计特点进行了介绍。

卫星结构分系统的“三化”设计及其发展

概述了卫星结构分系统的组成及其“三化”工作现状,分析了卫星结构分系统“三化”的发展方向,指出了实施的途径。

我国企业管理现状的再认识

党的十三大提出的我国处在社会主义初级阶段的论断,是我们沿着有中国特色的社会主义道路前进的理论基础,也是我们总结社会主义企业管理的历史经验、剖析和认识企业管理的复杂现状、探索和创建具有中国特色的社会主义企业管理科学的锐利武器。本文试图对企业管理的复杂现状和若干难题进行粗浅的探讨,并作为引玉之砖。

SIMULATION AND PERFORMANCE ANALYSIS OF NETWORK ON CHIP ARCHITECTURES

The network on chip（NoC）is used as a solution for the communication problems in a complex system on chip（SoC）design.To further enhance performances,the NoC architectures,a high level modeling and an evaluation method based on OPNET are proposed to analyze their performances on different injection rates and traffic patterns.Simulation results for general NoC in terms of the average latency and the throughput are analyzed and used as a guideline to make appropriate choices for a given application.Finally,a MPEG4 decoder is mapped on different NoC architectures.Results prove the effectiveness of the evaluation method.

Seventy Years’“Micropedology”1938-2008:The Past and Future

Although the first microscopic observations on soils date already from the beginning of the twentieth century, the publication of Kubiena＇s book ＂Micropedology＂ in 1937 is considered as the beginning of this new scientific discipline. This first system for micromorphological descriptions of soils is considered as morphoanalytical, analysing the fabric according to pure morphological criteria. In a second period Kuniena used a morphogenetic approach, directly relating the global observed fabric to genetic soil horizons. This system, mainly limited to European soils, was in general use till the early nineteen-seventies. End of the nineteen-fifties non- genetic soil classification systems were developed （e.g. USDA）. This trend prompted R. Brewer to publish in 1964 a new morphoanalytical system for fabric analysis, used till the end of last century. Because of some inconsistencies in this approach, a working group of the ISSS published in 1985 a new set of morphoanalytical concepts and associated terminology （Bullock et al.）, in 2003 adapted and extended by Stoops. Several morphosynthetic systems, expressing a complete soil microfabric in a single （compound） term have been proposed, but none was really successful. In 1967 Kubiena introduced the term ＂micromorphometry＂ to name a new branch of micromorphology quantifying the soil fabric, mainly evaluating changes in porosity and structure resulting from soil management. The necessity of dearly defined concepts and terms for fabric analysis of soils and regoliths, even as a need for standardisation of quantitative methods, are discussed in the conclusions.

Diversity patterns and phylogenetic structure of vascular plants along elevational gradients in a mountain ecosystem, South Korea

Recently, a phylogenetic diversity and community structure analysis as complementary to species-centric approaches in biodiversity studies provides new insights into the processes of community assembly. In this study, we analyzed species and phylogenetic diversity and community structures for woody and herbaceous plants along two elevational transects on Mt. Baekhwa, South Korea. The species richness and phylogenetic diversity of woody plants showed monotonic declining patterns with increasing elevation along all transects, whereas herbaceous plants showed different patterns, such as no relationship and a reversed unimodal pattern, between the study transects. The main drivers of these patterns were climate and habitat variables for woody and herbaceous plants, respectively. In addition, the phylogenetic community structure primarily showed phylogenetic clustering regulated by deterministic processes, especially environmental filtering, such as climate or habitat factors, along the two transects, although herbaceous plants along a transect depicted phylogenetic randomness as a result of a neutral process. Our findings suggest that deterministic and neutral processes may simultaneously control the community structures along small-scale elevational gradients such as local transects, although the deterministic process may be the predominant type.

Exploring proximity based peer clustering in BitTorrent-like Peer-to-Peer file sharing systems

A hierarchical clustered BitTorrent （CBT） system is proposed to improve the file sharing perior-mance of the BitTorrent system, in which peers are grouped into clusters in a large-scale BitTorrent-hke underlying overlay network in such a way that clusters are evenly distributed and that the peers within the cluster are relatively close to each other. A fluid model is developed to compare the performance of the proposed CBT system with the BitTorrent system, and the result shows that the CBT system can effectively improve the performance of the system. Simulation results also demonstrate that the CBT system improves the system scalabihty and efficiency while retaining the robustness and incentives of the original BitTorrent paradigm.

Temporal Data Mining Using Genetic Algorithm and Neural Network——A Case Study of Air Pollutant Forecasts

This paper integrates genetic algorithm and neura l network techniques to build new temporal predicting analysis tools for geographic information system (GIS). These new GIS tools can be readily applied in a practical and appropriate manner in spatial and temp oral research to patch the gaps in GIS data mining and knowledge discovery functions. The specific achievement here is the integration of related artificial intellig ent technologies into GIS software to establish a conceptual spatial and temporal analysis framework. And, by using this framework to develop an artificial intelligent spatial and tempor al information analyst (ASIA) system which then is fully utilized in the existin g GIS package. This study of air pollutants forecasting provides a geographical practical case to prove the rationalization and justness of the conceptual tempo ral analysis framework.

Estimating extreme temperature differences in steel box girder using long-term measurement data

The extreme temperature differences in fiat steel box girder of a cable-stayed bridge were studied.Firstly,by using the long-term measurement data collected by the structural health monitoring system installed on the Runyang Cable-stayed Bridge,the daily variations as well as seasonal ones of measured temperature differences in the box girder cross-section area were summarized.The probability distribution models of temperature differences were further established and the extreme temperature differences were estimated with a return period of 100 years.Finally,the temperature difference models in cross-section area were proposed for bridge thermal design.The results show that horizontal temperature differences in top plate and vertical temperature differences between top plate and bottom plate are considerable.All the positive and negative temperature differences can be described by the weighted sum of two Weibull distributions.The maximum positive and negative horizontal temperature differences in top plate are 10.30 ℃ and -13.80 ℃,respectively.And the maximum positive and negative vertical temperature differences between top plate and bottom plate are 17.30 ℃ and-3.70 ℃,respectively.For bridge thermal design,there are two vertical temperature difference models between top plate and bottom plate,and six horizontal temperature difference models in top plate.

Research on synchronous gear pump

Based on a comprehensive analysis of the structure and existing problems ofthe gear pump, provided a structure principle of a synchronous gear pump.The discussionsfocused on the working principle, construction features and finite element analysis ofthe hydraulic gear.The research indicates that the new pump has such advantages aslower noise, better distributed flow and a high work pressure, and it can be widely used inhydraulic systems.

Some Remarks Regarding Originality and Historical Transformations of Chopin＇s Mazurkas, as Based on the Mathematical Systematic Method of the Tonal Structure Analysis

Musical analysis enables us to study the various elements of a musical work, for example texture, m dynamics, or harmony （including tonality）. Thanks to musical analysis we are able to trace the compos technique, or assess the artistic value of given work. In addition to traditional, descriptive methods of e it ody, onal music analysis, we can observe in 20th century the development of methods based on science （mathematics, otherwise statistics）. Such methodologies allow us to obtain a strict understanding of the structure of musical pieces Applying mathematical methods for musical analysis seems very reasonable in relation to the output of Frederic Chopin, due to large originality of the elements of musical pieces of this composer. Present paper was written as a result of research related to the applying of numerical method of analysis for exploring the tonal structure of Chopin＇s works. The author＇s research method enables a strict analysis of the chord＇s domination that can be classified under given key （range）--taking into consideration the harmonic functions. By the method of analysis we can get charts that depict whole diatonic vertical music material of the given piece. The main objective of the present study is to describe observations on the high uniqueness in the tonal construction of selected Chopin＇s mazurkas, especially, when compared to the miniatures of other composers of the first half of the 19th century and previously analyzed Chopin＇s pieces： etudes, preludes, and songs.

Credibility and Security of Weighing System for Large Structure Object

The weighing system designed for large structure object is mainly composed of three parts. The part of hydraulic system is made up of hydraulic cylinders, high pressure hydraulic hoses and electric pumps; the part of computer controlling system comprises pressure sensors, displacement sensors, data acquisitions, RS 485 network and the computer controlling model; the part of loading system is composed of the fulcrum structure and the concrete girder. The measurement principle and composition of the weighing system are discussed in this paper. Credibility and security of the weighing system are fully considered during the design phase. The hydraulic system is controlled by pilot operated check valves in case of the sudden loss of system pressure. The states of all gauges and RS485 network are monitored by computer controlling system functioning in different modules. When the system is running incorrectly, it will be switched to manual mode and give alarm. The finite element method is employed to analyze fulcrum structure so that the system has enough intensity to be lifted. Hence the reliability of the whole system is enhanced.

Vibration Analysis of Frame Structure with Soil-Structure Interaction

A common design practice for dynamic loading assumes the frame fixed at their bases. In reality, the supporting soil medium allows movement to some extent due to its property to deform. This may decrease the overall stiffness of the structural system and may increase the natural period of the system. The effect of soil flexibility is suggested to be accounted through consideration of springs which have specified stiffness and soil half space. Results show that the dynamic response of frame structure to vibrations is due to applied dynamic load and is highly dependent on the soil type and the method of modeling soil structure interaction. The response of frame structure under dynamic load is higher in case of linear discrete independent spring as comparing with perfect bond cases. Except the response of frame in case of piles embedded in soft clay, half space are higher than frame with piles and linear elastic spring due to the interaction between the frequencies of applied load and frequencies of frame structure. Also, result showed that it is important to include the soil-structure interaction in the analysis of the system in order to correctly simulate the dynamic problem for controlling on the resonance phenomena.

Structural-acoustic coupling characteristics of honeycomb sandwich plate based on parameter sensitivity analysis

The structural-acoustic coupling model for isotropic thin elastic plate was extended to honeycomb sandwich plate(HSP) by applying Green function method.Then an equivalent circuit model of the weakly-strongly coupled system was proposed.Based on that,the estimation formulae of the coupled eigenfrequency were derived.The accuracy of the theoretical predictions was checked against experimental data,with good agreement achieved.Finally,the effects of HSP design parameters on the system coupling degree,the acoustic cavity eigenfrequency,and sound pressure response were analyzed.The results show that mechanical and acoustical characteristics of HSP can be improved by increasing the thickness of face sheet and reducing the mass density of material.

Estimation of Concrete Arch Dams Responses in Linear Domain Using Endurance Time Analysis Method

In this paper, Endurance Time Analysis （ETA） method which is a new time-history based dynamic pushover procedure is introduced and its application in linear analysis of concrete arch dams is investigated. In this method the structure is subjected to gradually intensifying acceleration functions and its performance is evaluated based on the length of the time duration that can satisfy required performance criteria. For this purpose Dez arch dam is selected as case study, fluid-structure interaction is taken into account and F.E. model of the system is excited in three performance levels. ETA method gives an approximation of maximum response at the equivalent target time, resulted from analyzing the system based on natural records. Extracted results are displacement, velocity and acceleration of the crest at crown cantilever. Results show using of ETA method can reduce at least 50% in number of analyses and 70% in total time of analyses at the current case. Furthermore, it is found that although the results of the ETA are not exactly consistent with the results of time-history analyses using real ground motions, errors are reasonable and ETA can identify performance levels of the dam with acceptable accuracy.

Concept and Evaluation of Ecosystem Intrinsic Value

Ecosystem valuation can serve as a basis of scientific support for decision-making. So far, the most popular methods for ecosystem valuation are ecosystem service valuation （ESV）, which is based on the utility of ecosystem to human beings rather than on the objective value of the ecosystem. After more than 10 years＇ application, it has been found that all losses of ESV were about 10% of the benefits of human activities. In this paper, the ecosystem intrinsic value （EIV） is defined. EIV is an objective value that emerges from the existence, structures, functions and processes of ecosystem, but independent with man, man＇s will and preferences. The valuating approach and methods used for EIV were developed by using energy approach and the methods of emergy analysis and eco-exergy analysis. The EIV calculated by emergy from the substance, energy and information of ecosystem and by eco-exergy from the structure and function of ecosystem represents the existent value and the externally working capacity of ecosystem, respectively. The approach and methods of EIV evaluation were applied to Xiamen Bay, China. The results showed that the marine EIV in Xiamen Bay was 209 billion RMB, including 116 billion RMB of emergy and 92.4 billion RMB of eco-exergy in 2010, nearly 30 times of ESV and 8.5 times of the GDP of Xiamen marine industry in 2010. The EIV in unit area of Xiarnen Bay is more than 10 times higher than the average global ESV in estuaries. It implied a potential undervaluation to ecosystem value by ESV calculation, which may mislead decisions-making processes.

Echo-state-network classification based multi-services awareness in high-speed optical passive networks

With the challenge of great growing of services diversity,service-oriented supporting ability is required by current high-speed passive optical network( PON). Aimed at enhancing the quality of service( Qo S) brought by diversified-services,this study proposes an echo state network( ESN)based multi-service awareness mechanism in 10-Gigabite ethernet passive optical network( 10GEPON). In the proposed approach,distributed architecture is adopted to realize this ESN based multi-service awareness. According to the network architecture of 10G-EPON,where a main ESN is running in OLT and a number of ESN agents works in ONUs. The main-ESN plays the main function of service-awareness from the total view of various kinds of services in 10G-EPON system,by full ESN training. Then,the reservoir information of well-trained ESN in OLT will be broadcasted to all ONUs and those ESN agents working in ONUs are allowed to conduct independent service-awareness function. Thus,resources allocation and transport policy are both determined only in ONUs. Simulation results show that the proposed mechanism is able to better support the ability of multiple services.

Generalized multi-layered granulations and approximations based on neighborhood systems under incomplete information systems

A generalized multi-layered granulation structure used by neighborhood systems is proposed. With granulated views, the concepts of approximations under incomplete information systems are studied, which are represented by covering of the universe. With respect to different levels of granulations, a pair of lower and upper approximations is defined and an approximation structure is investigated, which lead to a more general approximation structure. The generalized multi-layered granulation structure provides a basis of the proposed framework of granular computing. Using this framework, the interesting and useful results about information granulation and approximation reasoning can be obtained. This paper presents some useful explorations about the incomplete information systems from information views.

Minimizing of the only-insertion insdel systems

A more recent branch of natural computing is DNA computing. At the theoretical level, DNA computing is powerful. This is due to the fact that DNA structure and processing suggest a series of new data structures and operations, and to the fact of the massive parallelism. The insertion-deletion system （insdel system） is a DNA computing model based on two genetic operations： insertion and deletion which, working together, are very powerful, leading to characterizations of recursively enumerable lan- guages. When designing an insdel computer, it is natural to try to keep the underlying model as simple as possible. One idea is to use either only insertion operations or only deletion operations. By helping with a weak coding and a morphism, the family INS4^7DEL0^0 is equal to the family of recursively enumerable languages. It is an open problem proposed by Martin-Vide et al. on whether or not the parameters 4 and 7 appearing here can be replaced by smaller numbers. In this paper, our positive answer to this question is that INS2^4DEL0^0 can also play the same role as insertion and deletion. We suppose that the INS2^4DEL0^0 may be the least only-insertion insdel system in this situation. We will give some reasons supporting this conjecture in our paper.