Theoretical evaluation of stresses in a stream viscous-tiksotropical of a liquid

Ｔｈｅｐｒｏｂｌｅｍｏｆａｎａｎａｌｙｔｉｃａｌｒｅｓｅａｒｃｈｏｆｖｅｒｔｉｃａｌｄｉｓ ｐｌａｃｅｍｅｎｔｓｏｆａｇｒｉｄｕｎｄｅｒａｎｏｐｅｒａｔｉｏｎｏｆａｖｉｂｒａｔｏｒｓｈｏｕｌｄｔａｋｅｉｎｔｏａｃｃｏｕｎｔ:ａｔｅｎｓｉｏｎｏｆａｇｒｉｄ ,ｉｔａｍａｔｅｒｉａｌａｎｄａｍｏｕｎｔｄｅｗａｔｅｒｉｎｇｏｆａｍａｓｓｉｎａｚｏｎｅｏｆｖｉｂｒｏａｃｔｉｖａｔｉｏｎ .Ｆｏｒｔｈｅｄｅｓｃｒｉｐｔｉｏｎｏｆｖｅｒｔｉｃａｌｏｓｃｉｌｌａｔｉｏｎｓｏｆａｇｒｉｄｗｉｔｈａｐａｐｅｒｍａｓｓｕ…     

Simulation of Water-Resistance of a Clay Layer During Mining： Analysis of a Safe Water Head

Given previous research and prototypical geological conditions of a mining workface, we simulated fissure development in clay layers at the bottom of Quaternary strata and above bedrock, sand and water inrush during mining by model experiments. The results show that V-shaped fissures usually occur in the bottom clay layer at the front top of the active face and that the position of these fissures changes periodically with ground pressure intervals These fissures occur exactly in the area where the horizontal strain is concentrated. The results also demonstrate that the permeability coefficient of the cracked clay decreases while fissures tend to close. The permeability of the cracked bottom clay layer increases rapidly after a turning point in the permeability coefficient-water head curve （K-H curve） under a certain vertical load. Under static water pressure, the permeability coefficient of cracked clay decreases when load increases. A turning point in the K-H curve showed up and can be seen as a cutoff point to decide water inrush under a certain load level. Under an instantaneous water head, the greatest ability of the cracked clay to avoid drastic water inflow is a little higher than that under static conditions.     

Realization of Strongly Connected Direction of a Graph

ＲｅａｌｉｚａｔｉｏｎｏｆＳｔｒｏｎｇｌｙＣｏｎｎｅｃｔｅｄＤｉｒｅｃｔｉｏｎｏｆａＧｒａｐｈＺｈａｎｇＺｈｉｙｕ；ＺｈａｎｇＭｅｉｙｕ（ＮｏｒｔｈＣｈｉｎａＩｎｓｔｉｔｕｔｅｏｆＴｅｃｈｎｏｌｏｇｙ，Ｔａｉｙｕａｎ，Ｓｈａｎｘｉ，ＰＲＣ，０３０００...     

Quantum Dynamics of a Charge Qubit in a Squeezed Field

The quantum dynamics of a charge qubit, which makes up of a single-Cooper-pair box, are explored.The Cooper-pair box is irradiated by a squeezed field in an ideal one-mode cavity. By the result of the Schrodinger equation, the Cooper pairs number (N) is conveniently obtained. Then it is proved that the oscillations of the Cooper-pair number (N) are decreasing with the increasing squeezing parameter of the squeezed field.     

Note on a Theorem of Parthasarathy-Steerneman

本文从另一角度,推广了Parthasarathy及Steerneman关于概率测度卷积的强收敛性所得到的成果。     

The multi--intersection number of a graph

The intersection number, in (G), has been defined as the minimumcardinality of a set S which has n different subsets S_i such that each S_i can beassigned to the node v_i of G and nodes v_i, v_j are adjacent if and onlyif S_i∩S_j ≠0. We introduce the multiset intersection number min (G), defined similarly exceptthat multisets with elements in S may now be assigned to the nodes of G. Weprove that min (G) equals the smallest number ofcliques of G whose union is G.     

Investigation of the Dynamic Characteristics of a Rotor Bearing Assembly

ＩｎｖｅｓｔｉｇａｔｉｏｎｏｆｔｈｅＤｙｎａｍｉｃＣｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆａＲｏｔｏｒＢｅａｒｉｎｇＡｓｓｅｍｂｌｙ￥（刘庆明）（庞志成）ＬＩＵＱｉｎｇｍｉｎｇＰＡＮＧＺｈｉｃｈｅｎｇ（Ｄｅｐｔ．ｏｆＭｅｔｈａｎｉｃａｌＥｎｇｉｎｅｅｒｉｎ...     

Design and application of a new kind of rolling coupling

Based on Hertz theory of elastic contact and the design theory of ball bearings, a new type of rolling coupling was designed. The two halves of the rolling coupling can be moved relatively by a small axial force when a great moment is exerted on it. The rolling coupling was used to connect the principal axis and the decelerator of continuous extrusion machine and it can greatly decrease the harmful axial forces on the continuous machine. The engineering formulas for the contact stress and distance of apporach of the rolling elements were deduced and the method for designing the rolling couplings was proposed. The formulas for the forces exerted on the rolling element were verified by the experiment.     

Robust exponential control of a class of systems with uncertainties

The robust exponential stabilization problem for uncertain systems is studied.Based on the solution for a nominal linear quadratic regulator problem with a prescribed degree of stability,the methods of constructing state feedback controllers are devel-oped to ensure the robust stability of the closed loop system under the conditions weaker than the matching condition.Also,the cases where the matching condition is satisfied are considered in detail.Some examples are included to show the solution methods.     

Efficacy of chalcopyrite bioleaching using a pure and a mixed bacterium

To determine the efficacy of chalcopyrite bioleaching using pure cultures of Thiobacillus ferrooxidans or Thiobacillus thiooxidans and a mixed culture composed of Thiobacillus ferrooxidans and Thiobacillus thiooxidans, experiments were carried out in shake flasks with [Fe~(2 )] 4 g.L~(-1) and S 1 g.L~(-1) at pH=1.80, 130 r/min and 30℃. The tests showed that the copper extraction in a mixed culture composed of Thiobacillus ferrooxidans and Thiobacillus thiooxidans is higher than that in a pure culture. On the other hand, an important potential of Thiobacillus thiooxidans to leaching chalcopyrite was indicated. Thiobacillus thiooxidans can prevent jarosites accumulating on the substrate and allow further copper to dissolute through the action of ferric ion. The selection of the suitable pH in a leaching solution would be significant. Thiobacillus thiooxidans and Thiobacillus ferrooxidans play an important role in the bioleaching process. Finally, the mechanism and the reason for iron precipitation were also discussed in detail.     

Development of a GIS-based decision-support system of forest resource management

Based on forest inventory data and a variety of spatial data layers, including topographic maps, forest type maps, forest themes, etc., a multilevel decision-support system (DSS) for forest resource management was developed for Shangzhi National Forestry Bureau, Heilongjiang Province, China. This paper induced the procedure of the DSS development and its main functions, including displaying, cartography, dual-comprehensive querying of spatial and attribute data, GPS positioning, statistical analysis, updating resource data, etc. The applications of the DSS in resources analysis and management proved effective both in forestry bureau and forest farm levels. Traditional approaches of forest resource management were accordingly updated and the digitization of forest management was realized in deed for state-owned forest industries. The system provides a basis for rational forest management towards sustainable forestry by means of stratified management.     

The Application of UBET in Backward Simulation of a Blade

ＴｈｅＡｐｐｌｉｃａｔｉｏｎｏｆＵＢＥＴｉｎＢａｃｋｗａｒｄＳｉｍｕｌａｔｉｏｎｏｆａＢｌａｄｅＷＡＮＧＺｈｅｎ；ＸＵＥＫｅｍｉｎ；ＬＩＵＹｉｎｇｗｅｉ；ＷＡＮＧＨａｏ（王真）；（薛克敏）；（刘英伟）；（王昊）（Ｄｅｐｔ．ｏｆＭａｔｅｒｉａｌｓＳｃｉ...     

Microstructure of a Planting Material Consisting of Nutrition-Expansive Perlitic-Cement Composites

1　IntroductionVegetationisapositivefactortopreventsoilandwa terlosing .Butthecuttingslopes ,suchasthoseincon structinghighway ,railway ,hydraulicandelectricengi neering ,oftencausethenaturalvegetationbedamagedandunrecoverable .Inmanycasesthecoversoilofaslopeisrockyortotallyaridindryregions ,duetothelackoforganicmaterialsinthesoilmatrix .Underthisconditionaminimumtopsoillayerof 70to 10 0mminthicknessisrequired,sothevegetationisestablishedontheslopesuccessfully .Sincethetopsoilhaspoormechanica…     

Quantum Entropy of a Cooper-Pair Box in a Single-Mode Cavity Field

A Cooper-pair box biased by a classical voltage and also irradiated by a squeezed state field is considered in order to find new ways to quantum communication and calculation. The quantum dynamics of the Cooper-pair box and the entanglement which is the core theoretics of quantum communication and calculation is investigated in this system, which is related to the squeezing parameter of the squeezed state. A model of Hamiltonian which represents the interaction between box and quantum field is introduced. Finally, the relationship between the entanglement and the squeezing parameter of the squeezed state is demonstrated.     

Development of a Hybrid Photopolymer for Stereolithography

1 IntroductionRapid Prototyping (RP) was developed as a newmanufacture technique and considered a significant break-through in the field of manufacturing in the past 20years[1-4].The principle of RPis based on layer additivefabrication. Firstly, a three-dimensional object modelfromcomputer-aided design (CAD) is divided into manythinlayers by delaminatingsoftware .Thetwo-dimensionaldata of eachthinlayer control alaser beam,whichirradi-ates many materials like resin point-by-point ,and solid…     

Control Strategy of a Two-Lap Connection Converter

Two-lap sequential control converters are usually adopted to supply and improve the power factor of input side. The line harmonic damage generated by a sequential control thyristor converter can be serious. To solve this problem and seek an optimum control strategy, we derived the changeable regular of the line-input-current, the fundamen-tal-frequency-current, the harmonic-current-content and the harmonic total distortion ratio of the converter at different firing angles. We obtained relevant data from experiments with a sequential control system of a DC 2.2kW/220V motor. With the example of the operating condition of a DC mine elevator, the harmonic current is two times approximately in sequential control compared to synchronous control when the firing angle of the two converters differs in 30°. At different operating states of a two-lap connection converter, the ideal strategy is an exchange between sequential control and synchronous control, by which we can achieve the complementary goal of improving the power factor and harmonic effect. All analytical conclusions are supported by simulation and experimental results.     

Analysis of the Dynamic Response of a Shield Tunnel in Soft Soil Under a Metro-Train Vibrating Load

1 Introduction In recent years, with the development of traffic on ringroads around cities, more and more attention has been paid to the impact of this metro traffic oper- ating on lining structures and the environment. With the structure of the tunnel lining as the critical carrier and barrier in transmitting the vibrating load waves, the analysis of dynamic responses of tunnels is quite important. Some scientists have already made some investigations in this field. Zhang[1] studied the dy- n…     

Stiffness estimation of a parallel kinematic machine

This paper presents a simple yet comprehensive approach to quickly estimating the stiffness of a tripod-based parallel kinematic machine. This approach can be implemented in two steps. In the first step, the machine structure is decomposed into two substructures associated with the machine frame and parallel mechanism. The stiffness models of these two substructures are formulated by means of virtual work principle. This is followed by the second step that enables the stiffness model of the machine structure as a whole to be achieved by linear superposition. The 3D representations of the machine stiffness within the usable workspace are depicted and the contributions of different component rigidities to the machine stiffness are discussed. The result is compared with that obtained through finite element analysis.     

Preparation of Super Composite Cement with a Lower Clinker Content and a Larger Amount of Industrial Wastes

The effects of the grinling mode ,finencess,gypsum kinds and dosage,mix proportions on properties of the composite composite cements consisting of slag ,fly ash ,limestone and a lowr content clinker were investigated,respectively ,The results show that when thre proportions among slag ,fly ash and limestone are appropriate ,the grinding technology and system are reasonable ,the optinized gypsums and addities are effective,the 52.5R grade cement (52.5R grade cement menas a higher strength than 52.5 at ealy age) can be prepared by clinker dosage of 50% in weight,the 42.5R or 42.5 ,32.5 grade composite cement containing 40% and 30% clinker also may be made ,respectively ,Moreover,the high perfomance concrete preparde from the abover composite cements was studied experimentally.     

Integrable couplings of a generalized AKNS hierarchy

1　ＩＮＴＲＯＤＵＣＴＩＯＮＩｎｔｅｇｒａｂｌｅｃｏｕｐｌｉｎｇｓａｒｅａｎｉｎｔｅｒｅｓｔｉｎｇａｓｐｅｃｔｉｎｔｈｅｆｉｅｌｄｓｏｆｓｏｌｉｔｏｎｔｈｅｏｒｙ .ＩｔｏｒｉｇｉｎａｔｅｓｆｒｏｍａｎｉｎｖｅｓｔｉｇａｔｉｏｎｏｎｃｅｎｔｅｒｌｅｓｓＶｉｒ