To summarize the clinical experiences of microsurgical and endovascular treatments of complicated arteriovenous malformation (AVM) in the conditions of hybrid operating room.
The clinical data were ...collected and analyzed for 8 patients of complex AVM between June 2012 to June 2013. There were Spetzler grade III (n = 2) and grade IV (n = 6). And the lesions were complicated with intracranial aneurysms (n = 3) and located in motor area (n = 2) and basal ganglia (n = 2). Five cases of AVM with cerebral hemorrhage underwent emergency surgery, including digital subtraction angiography (DSA) plus intraoperative embolization plus surgical resection of AVM plus intraoperative DSA (iDSA). Two cases underwent embolization plus aneurysm surgery while another had AVM embolization plus AVM resection and γ knife treatment.
All surgical procedures, including iDSA, were completed in the same hybrid operating room. There was no change of surgical position or intraoperative mortality. Five patients of AVM hemorrhage undergoing
Based on the analysis of mathematical models of PMLSM and theories of vector control, it puts forward control system modeling method, two control loops which are the inner current-loop and the outer ...speed-loop are used in Matlab/Simulink, permanent magnet linear synchronous motors mathematical model is also modeled by end effect and three phase asymmetric winding. The simulation results proved the affectivity of the system's model and verified its control calculation way, and it also provided sufficient theoretical basis for designing and adjusting in practical control system.
Tellegen medium has long been a topic of debate, with its existence being contested over several decades. It was first proposed by Tellegen in 1948 and is characterized by a real-valued cross ...coupling between electric and magnetic responses, distinguishing it from the well-known chiral medium that has imaginary coupling coefficients. Significantly, Tellegen responses are closely linked to axion dynamics, an extensively studied subject in condensed matter physics. Here, we report the realization of Tellegen metamaterials in the microwave region through a judicious combination of subwavelength metallic resonators, gyromagnetic materials, and permanent magnet discs. We observe the key signature of the Tellegen response, i.e. a Kerr rotation for reflected wave, while the polarization remains the same in the transmission direction. The retrieved effective Tellegen parameter is several orders of magnitude greater than that of natural materials. Our work opens door to a variety of nonreciprocal photonic devices and may provide a platform for studying axion physics.
Thrust ripples are the main factors which affect the application and development of permanent magnet linear synchronous motor (PMLSM). In order to control and compensate the thrust fluctuations of ...permanent magnet synchronous motor, the mathematical model of thrust fluctuations must be established first. In this article, the theoretical analysis and derivation of the main factors affecting thrust ripples such as the disturbance of force ripple, edge effect are done in detail, after that a large number of experiments is carried out to test the thrust ripples, then the spectrum analysis of test data are made to find out the main frequency components and harmonics, last the mathematical model of thrust fluctuations are achieved, which provide the basis and foundation to compensate for thrust fluctuations through the methods of control.
Bi-rotary Milling Head in the machining process take direct cutting force, its thermal properties change on the accuracy of machine tool have an important influence. In this paper a wide range of ...load change processing conditions direct drive type double pendulum Angle milling head thermal properties condition to carry on the analysis, based on solidworks platform set up Bi-rotary Milling Head of the CAD model, the model into ANSYS platform. Determine the Bi-rotary Milling Head structure heat source, convection boundary conditions and constraints, the motor power changes the Bi- rotary Milling Head temperature field model and digital simulation, the varying load processing conditions, A, C thermal characteristic analysis, get the A, C axis load - temperature - time distribution, for the Bi-rotary Milling Head and structure design of high-grade CNC machine straight drive processing technology led to the development of theory and the technology base.
The linear motor drive technology is used more and widely in ultra-precision positioning and processing areas. Development of an integrated linear motor performance test platform can improve the ...integrated features of direct-drive products, their reliability, stability and application levels, and can also provide technical support for the formulation of relevant standards. The load module, as an important part of the linear motor test platform, plays an important role in motor tests. In order to meet the requirements of linear motor testing, this paper has studied the overall control program of the load module, design and control of current loops, suppression of the thrust fluctuations of the load motor, and compensation for inverter dead-time in motor driving. It has developed AC servo control unit and algorithms control program to achieve load motor motion control. Finally, both the relevant performance test and actual operation prove that the program and control strategies adapted are easy to control with characteristics of high precision and high stability in force and torque output , which can meet the test requirements of a direct-drive motor.
Topological singularities, such as Weyl points and Dirac points, can give rise to unidirectional propagation channels known as chiral zero modes (CZMs) when subject to a magnetic field. These CZMs ...are responsible for intriguing phenomena like the chiral anomaly in quantum systems. The propagation direction of each CZM is determined by both the applied magnetic field and the topological charge of the singularity point. While counter-propagating CZMs have been observed in 2D and 3D systems, the realization of co-propagating CZMs has remained elusive. Here we present the first experimental observation of co-propagating CZMs in magnetic photonic crystals hosting a single pair of ideal Weyl points WPs. By manipulating the crystal's structural configuration, we spatially alter the locations of the WPs, creating pseudo-magnetic fields in opposite directions between them. This arrangement results in a pair of CZMs that possess the same group velocity and co-propagate. Our work opens up new possibilities for topological manipulation of wave propagation and may lead to advancements in optical waveguides, switches, and various other applications.
A servo control system of a turntable is designed based on PMAC (programmable multi-axis motion controller). It includes the structure of the turntable, the hardware of control system, analyzes the ...adjustment method under the control mode of position/velocity loop and current loop, realizes the precise and real-time control of the position and velocity. The practical operation indicates that this motion control system meets the requirement of real-time turntable control, runs steadily and operates easily.
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