We investigate the maximally coherent states to provide a refinement in quantifying coherence and give a measure-independent definition of the coherence-preserving operations. A maximally coherent state can be considered as the resource to create arbitrary quantum states of the same dimension by merely incoherent operations. We propose that only the maximally coherent states should achieve the maximal value for a coherence measure and use this condition as an additional criterion for coherence measures to obtain a refinement in quantifying coherence which excludes the invalid and inefficient coherence measures. Under this new criterion, we then give a measure-independent definition of the coherence-preserving operations, which play a similar role in quantifying coherence as that played by the local unitary operations in the scenario of studying entanglement.

Recurrence of chronic subdural hematoma (CSH) is a significant problem in neurosurgical practice. Various risk factors associated with patient's characteristics and the pathogenesis of CSH have been investigated in many studies, but controversial findings are not uncommon. Therefore we made a retrospectively investigation focusing mainly on the factors associated with surgical techniques. in order to find out the factors that may affect the recurrence rate of CSH. The medical records of 97 consecutive patients with 121 CSHs, who were treated with burr-hole craniostomy and continuous drainage, were retrospectively reviewed. The relationships between the recurrence rate and some factors associated with surgery, such as location of burr-hole, thickness of residual hematoma, location of drainage catheter, intracapsular air postsurgery, duration of drainage were investigated. The average recurrence rate was 6.6% in this whole series. For patients with less than three days of drainage, the recurrence rate was 16.3%, whereas for those with 3 and more days of drainage, the recurrence rate was only 1.3%. The duration of drainage significantly related to recurrence rate. In addition, a higher recurrence rate seemed to be associated with more intracapsular air postsurgery, but it did not reach statistically significant level in this study. Prolonged duration of drainage did not increase the frequency of infection in this series. We found in this study that the duration of drainage play an important role in the treatment of CSH and 3 full days of drainage seems to be necessary, especially for patients of 60 years and over. We presumed that it takes at least 3 days of drainage for outer membrane of CSH to get the restoration of a normal balance between coagulation and fibrinolysis after surgery, which is necessary for termination of the vicious cycle and resolution of the hematoma.

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A microfabrication process for poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) based flexible piezoelectric devices is proposed using heat controlled spin coating and reactive ion etching (RIE) techniques. Dry etching of P(VDF-TrFE) in CF 4 +O 2 plasma is found to be more effective than that using SF 6 +O 2 or Ar+O 2 feed gas with the same radiofrequency power and pressure conditions. A maximum etching rate of 400 nm/min is obtained using the CF 4 +O 2 plasma with an oxygen concentration of 60% at , and heart beat sensors [7]. Cantilever shaped P(VDF-TrFE) actuators were also fabricated for mini-robots application, in which a multilayered P(VDF-TrFE) structure was proposed to achieve a large displacement with a low driving voltage [8]. Most of the PVDF based devices were fabricated using commercial PVDF films and traditional fabrication techniques such as scissoring, laser machining, and lamination [9,10]. With the aim of integrating piezoelectric polymers into microdevices, ionized evaporation, electrospray, electrospun, Langmuir-Blodgett deposition, and heat controlled spin coating methods were developed. Ionized evaporation and electrospray processes were reported to deposit PVDF films for pyroelectric infrared sensors in 1990s [11,12]. An electrospun method was employed to fabricate PVDF nanofibers for sensors and energy harvesters [5,13]. For fabrication of nonvolatile memory devices, low-temperature fabrication approaches including Langmuir-Blodgett deposition [14,15] and spin coating methods [16] were developed. The spin coated P(VDF-TrFE) films, intrinsically tending to form phase I crystal with a high remanent polarization, are

Microresonators with mechanical nonlinearity are applied to sensing based on the noise-enhanced stochastic transition of the vibration amplitude in bistable mechanical systems at resonance. Noise-enhanced stochastic transitions can amplify a signal in a nonlinear system. It was found that 100-nm-thick single-crystalline silicon resonators exhibit mechanical nonlinearity with both negative and positive nonlinear coefficients, depending on the vibration frequency at large vibration amplitudes. It was demonstrated that the noise-enhanced stochastic transition can be synchronized with periodic optical stimuli with in-phase or anti-phase, depending on the operation frequency. In addition, the detection of a magnetic field was demonstrated using a resonator with a micromagnet on the basis of noise-enhanced transitions.