Seismic structural control using semi-active tuned mass dampers

This paper focuses on how to determine the instantaneous damping of the semi-active tuned mass damper (SATMD) with continuously variable damping.An off-and-towards-equilibrium (OTE) algorithm is employed to examine the control performance of the structure/SATMD system by considering the damping as an assumptive control action.The damping modification of the SATMD is carried out according to the proposed OTE algorithm,which is formulated based on analysis of the structural movement under external excitations,and the measured responses of the structure at every time instant. As examples two numerical simulations of a five-storey and a ten-storey shear structures with a SATMD on the roof are conducted.The effectiveness on vibration reduction of MDOF systems subjected to seismic excitations is discussed.Analysis results show that the behavior of the structure with a SATMD is significantly improved and the feasibility of applying the OTE algorithm to the structural control design of SATMD is also verified.

Experimental study on seismic behavior of semi-rigid connection between steel beam and concrete wall

Beam-column or beam-wall connections are an important problem in high-rise buildings. In this study, based on the analysis of an example structure, an analytical model for design of the semi-rigid connections between steel beams and RC walls in high-rise hybrid buildings is proposed. Also, the mechanical characteristics of these connections subjected to low-reversed cyclic loading are investigated through comparison of experimental results from three semi-rigid connections and two rigid connections. Moreover, some latent problems for design of these connections as well as the corresponding solutions are discussed. The results from the experiments and analyses indicate that semi-rigid connections exhibit satisfactory capacity and seismic performance, and the proposed design can be used in practice.

Excess Liquidity Control Requires a Multi-Pronged Approach

As China opens wider to the outside world, excess liquidity has become an outstanding issue in economic operations. This paper holds that China's liquidity is relatively excessive at the present time, and such excess liquidity is a reflection of domestic and foreign economic contradictions on the monetary level. Excess liquidity will pose a potential hazard to macroeconomic operation, and a multi-pronged approach should be taken to curb and control its sources at home and abroad.

Optical and electronic performances of CVD diamond film andits applications in radiation detectors

The outstanding properties of CVD diamond film such as electronic, optical, thermal and mechanical and the high radiation hardness have made it an ideal candidate material for radiation detectors in severe environments. Fabrication of ＇detector grade＇ CVD diamond films and development of CVD diamond detectors have been leading edge subjects. Micro-strip gas chamber （MSGC） fabricated on CVD diamond substrate would overcome the charge-up effect and the substrate instability, which has been a hotspot in the research of gas detectors.

An Introduction to 2-CCD Digital Particle Image Velocimetry System and Its Application in Ocean Engineering

The basic principle of particle image velocinmetry (PIV) is described. When a PIV image is analyzed by the method of auto-correlation, there is a direction ambiguity of 180 degrees iii velocity measurement. The problem can be solved by using 'Image Shifting Technique', but this makes devices much complicated and difficult to control. A new arrangement of 2-CCD (Charge Coupled Device) fully digitized PIV system, which can also solve the problem successfully, is introduced in the paper. As an example of application of the system, an experimental result of flow field around a horizontal cylinder in wave is presented.

IDENTIFICATION OF WOOD AND BARK EXTRACTIVES AND THEIR TOXICOLOGICAL EFFECTS ON THE TMP EFFLUENTS

Wood extractives in model TMP effluents and bio-treated TMP mill effluent were extracted, isolated with liquid-liquid extraction, and analyzed with GC/MS following sylilation. Acute and chronic toxicity of the effluent samples were tested with Ceriodaphnia dubia. Wood and bark extractives are responsible for the toxicity of the TMP effluent to aquatic life. Resin and fatty acids have a dominating contribution to acute toxicity. Removal of them from the effluent cannot deplete all toxicants, some neutral extractives such as phytosterols, are still chronically toxic to Ceriodaphnia dubia. Wood bark has a dramatic impact on acute toxicity of the TMP effluent. Only 5% of spruce bark addition can increase acute toxicity by 38.4%. However, it has a reverse trend for chronic toxicity, which indicates that some neutral wood extractives may play important role in chronic toxicity of the TMP effluent as well. Successful control of the debarking process and debark effluents is essential for achieving high-quality effluent treatment.

High accuracy compact finite difference methods and their applications

Numerical simulation of complex flow fields with multi-scale structures is one of the most important and challenging branches of computational fluid dynamics. From linear analysis and numerical experiments it has been discovered that the higher-order accurate method can give reliable and efficient computational results, as well as better resolution of the complex flow fields with multi-scale structures. Compact finite difference schemes, which feature higher-order accuracy and spectral-like resolution with smaller stencils and easier application of boundary conditions, has attracted more and more interest and attention.

Research of testing method based on UML statecharts

Unified modeling language （UML） is a powerful graphical modeling language with intuitional meaning. It provides various diagrams to depict system characteristics and complex environment from different viewpoints and different application layers. UML-based software development and modeling environments have been widely accepted in industry, including areas in which safety is an important issue such as spaceflight, defense, automobile, etc. To ensure and improve software quality becomes a main concern in the field. As one of the key techniques for software quality, software testing can effectively detect system faults. UML based software testing based is an important research direction in software engineering. The key to software testing is the generation of test cases. This dissertation studies an approach to generating test cases from UML statecharts.

Application of experimental design techniques to structural simulation meta-model building using neural network

Neural networks are being used to construct meta-models in numerical simulation of structures.In addition to network structures and training algorithms,training samples also greatly affect the accuracy of neural network models.In this paper,some existing main sampling techniques are evaluated,including techniques based on experimental design theory, random selection,and rotating sampling.First,advantages and disadvantages of each technique are reviewed.Then,seven techniques are used to generate samples for training radial neural networks models for two benchmarks:an antenna model and an aircraft model.Results show that the uniform design,in which the number of samples and mean square error network models are considered,is the best sampling technique for neural network based meta-model building.

Multidirectional Gaussian Mixture Models for Nonlinear Uncertainty Propagation

Monte Carlo simulations are an accurate but computationally expensive procedure for approximating the resultant non-Gaussian probability density function(PDF)after propagation of an initial Gaussian PDF through a nonlinear function.Univariate splitting libraries for Gaussian Mixture Models(GMMs)exist with up to five elements in the literature.The number of splits are extended in the present work by generating three homoscedastic univariate splitting libraries with up to 39 elements.Mulitvariate GMMs are typically handled with splits along a single direction.Instead,we generate a regular multidirectional grid over the initial multivariate Gaussian distribution by recursively applying the splitting library along multiple directions.The splitting direction is arbitrary and no longer limited to directions parallel to the columns of the square-root of the covariance matrix.A second order Stirling’s interpolation of the nonlinear function evaluated at the mean of the initial Gaussian distribution is used to quantify nonlinearity along candidate splitting directions.The directions with the highest nonlinearity benefit most from splitting.The Multidirectional GMM(MGMM)has applications for uncertainty quantification with computationally intensive nonlinear functions.The variable number of splits in each direction allows for a spectrum of models in the accuracy versus compute time design space,filling the gap between expensive Monte Carlos and fast linearized models.The multidirectional method is demonstrated with four test cases,including an orbit uncertainty propagation case,to illustrate the benefit of splitting along multiple directions and of ranking the splitting directions.

FIBER ORIENTATION DISTRIBUTION OF PAPER SURFACE CALCULATED BY IMAGE ANALYSIS

Anisotropy of paper is an important parameter of paper structure. Image analysis technique was improved for accurate fiber orientation in paper surfaces. Image analysis using Fast Fourier Transform was demonstrated to be an effective means to determine fiber orientation angle and its intensity. Binarization process of micrograph images of paper surface and precise calculation for average Fourier coefficients as an angular distribution by interpolation developed were found to improve the accuracy. This analysis method was applied to digital optical micrographs and scanning electron micrographs of paper. A laboratory handsheet showed a large deviation in the average value of fiber orientation angle, but some kinds of machine-made paper showed about 90 degrees in the orientation angle with very small deviations as expected. Korea and Japanese paper made in the traditional ways showed its own characteristic depending on its hand making processes.

Breaking Criteria for Regular Waves on Gentle Slopes

Nelson pointed out that the wave breaking criterion( H/d)(b) for gentle slopes( i < 1/100), in which H is the wave height and d is the water depth at the breaking point, is smaller than that for beach slopes of i > 1/100, i. e., the value oft H/d)(b) for gentle slopes may be smaller than 0.6. Goda indicated that the wave breaking criterion given by himself is a result based on theoretical study, so it should be also correct and can be used for gentle beaches, i.e., the value of(H/d)(b) for gentle slopes may be still larger than 0.7. By use of high order nonlinear wave theory, this problem is analyzed in this study and the reason why there is a large difference between different studies is explained. Moreover, the bottom energy loss during wave propagation is considered and the critical slope for the absence of wave breaking is also analyzed.

China's Relations with Africa:Building a Harmonious World

The Sino-African relationship is one of the most important inter-continental relationships in the world.It is unique both in its origin and evolution and plays an important role on the world stage.Since the establishment of diplomatic relations in the mid-1950s,traditional,friendly and cooperative relations between China and African countries have developed rapidly,reaching an historic high in 2000 when both sides proclaimed the establishment of a new type of strategic partnership. Transcending Western traditional value and logic of thinking,such as the supremacy of international interests and power control,Sino-African relations have created a new model in international relations,featuring equality,peaceful coexistence and friendly cooperation.This promotes African development and the democratization process in both international relations and the global community.From China's perspective,it spreads China's idea of harmonious culture and harmonious diplomacy,thus promoting world peace and development,and contributing towards building a harmonious world.

Strategy of converting Jiangsu Province A Foreign-trade Large Province into A Foreign-trade Strong Province

Jiangsu Province, after executing economic inter- nationalization strategy and establishing the strategic goal of foreign-trade strong province,meaning to pur- sue a dominating position in the foreign trade relations, has become one of the foreign-trade large provinces of China and provided considerable international com- petitive power in some important fields. The period of the first twenty years of this century will be the impor- tant strategic favorable opportunity period for Chinese development. The external motive force of our coun- try for the economic development will not weaken greatly. The economic society of Jiangsu Province will walk into the industrialization type-transforming period, urbanization acceleration period, internation- alization advancement period, market consummation period and information penetration period. In order to promote Jiangsu Province converting from a foreign- trade large province into a foreign-trade strong province, Jiangsu should command the foreign-trade affairs through the scientific evolution concept, man- age the relation between the opening to the outside world and the domestic development, comply with the economy globalization, propel the internationalization of production, industry, capital and talents, improve the hierarchy of opening to the outside world, and quicken the internationalization progress. Also, Jiangsu province should maintain the steady continuous for- eign-trade growth, change the foreign-trade growth mode, modify the imports and exports merchandise composition and establish the marketing system to the international market. Furthermore, under the condition of moderate growth of general quantity of foreign trade, Jiangsu Province should advance and modify the im- ports and exports merchandise composition, improve the technology and value-added content of the export production, create the independent trademarks of the export production, foster the leading companies hav- ing the independent development ability, develop the service industry, promote the processing trade type- transforming, optimize the foreign-trade spatial distribution, and deal actively with the international trade frictions while exploiting the international markets. In the meanwhile, Jiangsu Province should modify the drawback policy, control the export of the resource products, improve the materials circulation management of corporations in the export manufac- turing district, modify the policy of processing trade, encourage the localization, increase the value-added rate of processing trade, develop the processing trade overseas, raise the important resource stockpile properly, perfect the cost policy of the export merchandise, and bring the guild into play to maintain the export order.