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Surface acoustic waves （SAWs） are elastic waves that propagate on the surface of a solid, much like waves on the ocean, with SAW devices used widely in communication and sensing. The ability to dynamically control the properties of SAWs would allow the creation of devices with improved performance or new functionality. However, so far it has proved extremely difficult to develop a practical way of achieving this control. In this paper we demonstrate voltage control of SAWs in a hybrid graphene-lithium niobate device. The velocity shift of the SAWs was measured as the conductivity of the graphene was modulated using an ion-gel gate, with a 0.1% velocity shift achieved for a bias of approximately 1 V. This velocity shift is comparable to that previously achieved in much more complicated hybrid semiconductor devices, and optimization of this approach could therefore lead to a practical, cost-effective voltage-controlled velocity shifter. In addition, the piezoelectric fields associated with the SAW can also be used to trap and transport the charge carriers within the graphene. Uniquely to graphene, we show that the acoustoelectric current in the same device can be reversed, and switched off, using the gate voltage.

The immune system exists in harmony and also with the potential for dynamic control in healthy individuals. Our healthy body needs to sense the presence of microbes and react through both innate and adaptive immunity to elim- inate infection. How our immune system senses the initiation, progression, and ter- mination of the inflammatory process is critical for maintaining immune home- ostasis. Thanks to the elegant experi- mental progress in using conditional knockout animal models, we have,

This paper aims to reveal the multi-optimal mechanisms for dynamic control in dragonfly wings. By combining the Arnold circulation with such micro/nano structures as the hollow inside constructions of the pterostigma, veins and spikes, dragonfly wings can create variable mass, variable rotating inertia and variable natural frequency. This marvelous ability enables dragonflies to overcome the contradictory requirements of both light-weight-wing and heavy-weight-wing, and displays the multi-optimal mechanisms for the excellent flying ability and dynamic control capacity of dragonflies. These results provide new perspectives for understanding the wings’ functions and new inspirations for bionic manufactures.

In the present paper the problem of disturbance rejection of single input-single output neutral time delay systems with multiple measurable disturbances is solved via dynamic controllers. In particular, the general form of the controller matrices is presented, while the necessary and sufficient conditions for the controller to be realizable are offered. The proposed technique is applied to a test case neutral time delay central heating system. In particular, the nonlinear model of the plant and its linearized approximation are presented. Based on the linearized model, a two-stage controller is designed in order to regulate the room temperature and the boiler effluent temperature. The performance of the closed loop system is investigated through computational experiments.

There are significant effects of process parameters on internal qualities of bloom, and these process parameters are as follows. position and reduction amount, reduction distribution, reduction rate, and so on. Developing a control model is the key to apply soft reduction technology successfully. As the research object, 360 mm ×450 mm bloom caster in PISCO （Panzhihua Iron and Steel Co. ） has been studied, and the research method for control model of dynamic soft reduction has been proposed. On the basis of solidification and heat transfer model, the position of soft reduction and reduction distribution of each frame are determined according to the bloom temperature distribution and solid fraction in bloom center calculated. Production practice shows that the ratio of center porosity which is less than or equal to 1.0, increased to 97.27%, ratio of central segregation which is less than or equal to 0.5, increased to 80.91%, and ratio of central carbon segregation index which is more than or equal to 1.10, decreased to 4% with the applying model of dynamic soft reduction.