摘要：The problem of finding stabilizing controllers for switched systems is an area of much research interest as conventional concepts from continuous time and discrete event dynamics do not hold true for these *** solutions have been proposed,most of which are based on finding the existence of a common Lyapunov function(CLF) or a multiple Lyapunov function(MLF) where the key is to formulate the problem into a set of linear matrix inequalities(LMIs).An alternative method for finding the existence of a CLF by solving two sets of linear inequalities(LIs) has previously been *** method is seen to be less computationally taxing compared to methods based on solving *** substantiate this,the computational ability of three numerical computational solvers,LMI solver,cvx,and Yalmip,as well as the symbolic computational program Maple were tested.A specific switched system comprising four second-order subsystems was used as a test *** the obtained solutions,the validity of the controllers and the corresponding CLF was *** was found that all tested solvers were able to correctly solve the *** issue of rounding-off error in numerical computation based software is discussed in *** test revealed that the guarantee of stability became uncertain when the rounding off was at a different decimal *** use of different external solvers led to the same conclusion in terms of the stability of switched *** a result,a shift from using a conventional numerical computation based program to using computer algebra is suggested.

摘要：Biodegradable Mg-Zn alloy was synthesized using mechanical alloying where a statistical model was developed using fractional factorial design to predict elastic modulus and mass loss of the bulk *** effects of mechanical alloying parameters(i.e.,milling time,milling speed,ball-to-powder mass ratio and Zn content)and their interactions were investigated involving 4 numerical factors with 2 replicates,thus 16 runs of two-level fractional factorial *** of analysis of variance(ANOVA),regression analysis and R2 test indicated good accuracy of the *** statistical model determined that the elastic modulus of biodegradable Mg-Zn alloy was between 40.18 and 47.88 GPa,which was improved and resembled that of natural bone(30-57 GPa).Corrosion resistance(mass loss of pure Mg,33.74 mg)was enhanced with addition of 3%-10%Zn(between 9.32 and 15.38 mg).The most significant independent variable was Zn content,and only the interaction of milling time and ball-to-powder mass ratio was significant as P-value was less than ***,mechanical properties(represented by elastic modulus)and corrosion resistance(represented by mass loss)of biodegradable Mg-Zn alloy can be statistically predicted according to the developed models.

摘要：Wind energy sources have different structures and functions from conventional power plants in the power *** resources can affect the exchange of active and reactive power of the ***,power system stability will be affected by the performance of wind power plants,especially in the event of a *** this paper,the improvement of the dynamic stability in power system equipped by wind farm is examined through the supplementary controller design in the high voltage direct current(HVDC)based on voltage source converter(VSC)transmission *** this regard,impacts of the VSC HVDC system and wind farm on the improvement of system stability are ***,an algorithm based on controllability(observability)concept is proposed to select most appropriate and effective coupling between inputs-outputs(IO)signals of system in different work *** selected coupling is used to apply damping controller ***,a fractional order PID controller(FO-PID)based on exchange market algorithm(EMA)is designed as damping *** analysis of the results shows that the wind farm does not directly contribute to the improvement of the dynamic stability of power ***,it can increase the controllability of the oscillatory mode and improve the performance of the supplementary controller.

摘要：Rock excavation in quarries is normally carried out by using explosives. The steps in planning of cutting face are based on the appropriate design for angles of cut and the optimum consumption of charge weights. Priority procedures in planning are the stability of bench excavation,vibration evaluation,and the selection for the blast patterns. The methods of analysis are described and compared with field results. From several cases of trial cut angles and changing geometry of blast dimensions,the result of an optimum pattern in a specific quarry,with respect to the acceptable global unit cost is achieved.

摘要：本文对各种磁流变阻尼器的优化设计、制造和智能应用以及自供电和自感应技术的最新进展进行了综述。本文讨论了磁流变阻尼器的基本设计和结构以及各种类型的配置,以了解它们在各种环境和目的下的多功能性。为了应对不同的应用,本文介绍了设计的修改、优化和改进。节能是当前的终极需求,是对现代技术的挑战。磁流变阻尼器需要改进,以确保较低的电流供应得到较高的效力。这项工作将有助于在各种结构中使用磁流变阻尼器,使其以最小的电流供应进行振动控制,并在优化中获得最佳结果。

摘要：In modem four-stroke engine technology, variable valve timing and lift control offers potential benefits for making a high-performance engine. A novel electro-hydraulic fully variable valve train for four-stroke automotive engines is introduced. The construction of the nonlinear mathematic model of the valve train system and its dynamic analysis are also presented. Experimental and simulation results show that the novel electro-hydraulic valve train can achieve fully variable valve timing and lift control. Consequently the engine performance on different loads and speeds will be significantly increased. The technology also permits the elimination of the traditional throttle valve in the gasoline engines and increases engine design flexibility.

摘要：Different strategies can be used to perform reparations and reinforcements of ancient bolted and riveted metallic bridges. As the riveting process is not currently a common practice, it requires proper equipment and skilled workers. Another solution is the use of welding. However, the weldability of old steels is poor. Bolts are very attractive alternative solutions, and are most commonly used to repair old metallic bridges. Fitted bolts are expensive solutions; the alternative is the use of resin-injected bolts. The behavior of bolted joints with preloaded resin-injected bolts has been studied using quasi-static and creep tests; however, few studies on the slip and fatigue behavior of these joints can be found in the literature. This paper presents an overview of a few experimental programs that were carried out by several authors aiming at evaluating the fatigue behavior of single and double shear resin-injected bolted connections. A comparison between the experimental data of joints with preloaded standard bolts and preloaded resin- injected bolts shows a fatigue strength reduction in the latter. Since Eurocode 3 （EC3） suggests the same fatigue strength curve for joints made of resin-injected bolts and standard bolts, this may raise some con- cerns. Furthermore, research on the feasibility of using both bonded and bolted connections is shown. This last study was performed with high-strength low-alloy structural steel plates and an acrylic struc- tural adhesive for metal bonding. For both case studies, a statistical analysis is performed on fatigue experimental data using linearized boundaries and the Castillo and Fernandez-Canteli model. Fatigue design curves are proposed and compared with the design suggestions of several European and North American standards,

摘要：Reversible logic has recently gained significant interest due to its inherent ability to reduce energy dissipation,which is the primary need for low-power digital *** of the newest areas of relevant study is reversible logic,which has applications in many areas,including nanotechnology,DNA computing,quantum computing,fault tolerance,and low-power complementary metal-oxide-semiconductor(CMOS).An electrical circuit is classified as reversible if it has an equal number of inputs and outputs,and a one-to-one relationship.A reversible circuit is conservative if the EXOR of the inputs and the EXOR of the outputs are *** addition,quantum-dot cellular automata(QCA)is one of the state-of-the-art approaches that can be used as an alternative to traditional ***,we propose an efficient conservative gate with low power demand and high speed in this ***,we present a reversible gate called ANG(Ahmadpour Navimipour Gate).Then,two non-resistant QCA ANG and reversible fault-tolerant ANG structures are implemented in QCA *** suggested reversible gate is realized through the Miller ***,reversible fault-tolerant ANG is implemented by the 2DW clocking ***,the power consumption of the suggested ANG is assessed under different energy ranges(0.5Ek,1.0Ek,and 1.5Ek).Simulations of the structures and analysis of their power consumption are performed using QCADesigner 2.0.03 and QCAPro *** proposed gate shows great improvements compared to recent designs.

摘要：Classical transonic hodograph-based design methods are employed and revitalized using modern numerical tools to illustrate the design of a symmetrical accelerating-decelerating nozzle throat design. The concept of Elliptic Continuation is applied to solve transonic boundary value problems avoiding the inherently nonlinear nature of the basic equations and obtaining transonic flow examples using the Method of Characteristics in an inverse mode. Purpose of the present paper, besides describing a new special flow example, is to keep these classical methods alive for education of a new generation of creative engineers.

摘要：Larger and larger proportions of aluminium castings,especially those produced by the die casting process,can be observed during recent years in the automotive industry,house-hold articles and *** case of the automotive industry,apart from the traditional elements produced by the die pressure method such as engine blocks or crank shaft bedplates,aluminium is displacing steel from structural parts of cars('body in white').The current state and development directions of the structural solutions of cold-chamber die castings are analysed in this *** solutions drive the prospective development of these machines and die casting *** focus is mainly on essential functional systems such as:hydraulic drives of closing and locking units,as well as pressing in die machines of known companies present on the European market.