A Compact Piezo-Inertia Actuator Utilizing the Double-Rocker Flexure Hinge Mechanism.

With a simple structure and control method, the piezo-inertia actuator is a preferred embodiment in the field of microprecision industry. However, most of the previously reported actuators are unable to achieve a high speed, high resolution, and low deviation between positive and reverse velocities at the same time. To achieve a high speed, high resolution, and low deviation, in this paper we present a compact piezo-inertia actuator with a double rocker-type flexure hinge mechanism. The structure and operating principle are discussed in detail. To study the load capacity, voltage characteristics, and frequency characteristics of the actuator, we made a prototype and conducted a series of experiment. The results indicate good linearity in both positive and negative output displacements. The maximum positive and negative velocities are about 10.63 mm/s and 10.12 mm/s, respectively, and the corresponding speed deviation is 4.9%. The positive and negative positioning resolutions are 42.5 nm and 52.5 nm, respectively. In addition, the maximum output force is 220 g. These results show that the designed actuator has a minor speed deviation and good output characteristics.

Evolution of the Morphology and Magnetic Properties of Flaky FeSiAl/MFe2O4 (M = Mn, Co, Ni, Cu, Zn) Composites.

Nanosized spinel ferrites MFe2O4 (M = Mn, Co, Ni, Cu, Zn)-coated flaky FeSiAl alloy composites were synthesized successfully. Nano-ferrites preferentially grow into nanoplatelets due to induced or restricted growth on the flaky surface of FeSiAl. With annealing temperature increasing, the ferrites' nanosheets thicken gradually and then grow into irregular particles. The annealing temperature not only affects the nanosized morphology and coating but also the magnetic properties of flaky FeSiAl composites. The saturation magnetization of CuFe2O4- or NiFe2O4-coated FeSiAl is approximate 69 emu/g, where the value of MnFe2O4-, CoFe2O4- and ZnFe2O4-coated FeSiAl show a decreasing trend generally from 64 emu/g to 55.7 emu/g annealing at 800 °C, respectively. The saturation magnetization of flaky FeSiAl composites was improved with the increased annealing temperature, except for those coated with ZnFe2O4 and NiFe2O4. These results are useful for improving the comprehensive properties of ferrite-coated flaky FeSiAl alloy composites.

NH3 assisted photoreduction and N-doping of graphene oxide for high performance electrode materials in supercapacitors.

Nitrogen-doped graphene was synthesized by simple photoreduction of graphene oxide (GO) deposited on nickel foam under NH3 atmosphere. The combination of photoreduction and NH3 not only reduces the GO in a shorter time but also induces nitrogen doping easily. The nitrogen doped content of N-rGO@NF reaches a high of 5.99 at% with 15 min of irradiation. The nitrogen-doped graphene deposited on Ni foam (N-rGO@NF) can be directly used as an electrode for supercapacitors, without any conductive agents and polymer binders. In the electrochemical measurement, N-rGO@NF displays remarkable electrochemical performance. In particular, the N-rGO@NF irradiated for 45 min at a high current density of 92.3 A g(-1) retained about 77% (190.4 F g(-1)) of its initial specific capacitance (247.1 F g(-1) at 0.31 A g(-1)). Furthermore, the stable voltage window could be extended to 2.0 and 1.5 V by using Li2SO4 and a mixed Li2SO4/KOH electrolyte, and the maximum energy density was high up to 32.6 and 21.2 Wh kg(-1), respectively. The results show that compared to Li2SO4, a mixed electrolyte (Li2SO4/KOH) more efficiently balances the relationship between the high energy densities and high power densities.

A three-dimensional visualisation preoperative treatment planning system in microwave ablation for liver cancer: a preliminary clinical application.

OBJECTIVES: The aim of this study was to evaluate the clinical application value of a 3D visualisation preoperative treatment planning system in microwave ablation for liver cancer. METHODS: From December 2011 to November 2012, 94 enrolment patients of liver cancer were divided into two groups. The 3D preoperative planning group included 36 patients with 44 lesions, who underwent microwave ablation with the aid of the self-developed 3D visualisation preoperative treatment planning system. The 2D preoperative planning group included 58 patients with 64 lesions, who underwent microwave ablation according to conventional 2D image preoperative planning methods. After microwave ablation, therapeutic efficacy was assessed by contrast-enhanced imaging during follow-up. RESULTS: The 3D preoperative planning group had a higher success rate of first ablation than the 2D preoperative planning group (p = 0.01). There were more sessions in the 2D preoperative planning group than in the 3D preoperative planning group (p = 0.002). There were no significant differences in technique effectiveness rate between the 2D preoperative planning group (96.55%) and the 3D preoperative planning group (100%) according to the contrast-enhanced imaging follow-up after microwave ablation (p = 0.64). There were no significant differences in the rate of LTP between the 2D preoperative planning group and the 3D preoperative planning group (p = 0.64) during 3-12 months follow up (median 6 months). CONCLUSIONS: Compared with the 2D preoperative planning group, the 3D preoperative planning group had a higher success rate of first ablation and fewer sessions. Therefore, the 3D visualisation preoperative treatment planning system has a relatively high clinical application value.

Fast GPU-based CT reconstruction applied in ablation treatment for hepatocellular carcinoma.

OBJECTIVE: To develop an image visualization system based on graphic processing unit (GPU) hardware acceleration for clinical use in hepatocellular carcinoma (HCC) interventional planning. METHODS: We developed a liver tumor planning tool to assist the physician in providing patient-specific analysis and visualization. We employed a spatial distance computation algorithm to determine the spatial location of tumors and their relation to the main hepatic vessels. GPU hardware acceleration was implemented for rapid calculation of the spatial distance from the tumor surface to the surrounding vascular territories. RESULTS: The algorithm for spatial distance provided an accurate minimum value for the distance from the tumor surface to the surrounding duct system as well as the region of interest (ROI). Analyzing the data (mean CPU time = 43.14 ± 29.34; mean GPU time = 0.41 ± 0.38) using an independent samples t-test, the result showed a remarkable difference (p < 0.001). Thus, GPU hardware acceleration performed the distance arithmetic at higher rates than conventional CPUs. CONCLUSIONS: The visual assistance tool performs as an intuitive and objective module in clinical cases, and is expected to help physicians achieve a more reliable treatment in liver tumor patients. As such, we believe it represents an improvement in image guided preoperative planning.

Integration of the Image-Guided Surgery Toolkit (IGSTK) into the Medical Imaging Interaction Toolkit (MITK).

The development cycle of an image-guided surgery navigation system is too long to meet current clinical needs. This paper presents an integrated system developed by the integration of two open-source software (IGSTK and MITK) to shorten the development cycle of the image-guided surgery navigation system and save human resources simultaneously. An image-guided surgery navigation system was established by connecting the two aforementioned open-source software libraries. It used the Medical Imaging Interaction Toolkit (MITK) as a framework providing image processing tools for the image-guided surgery navigation system of medical imaging software with a high degree of interaction and used the Image-Guided Surgery Toolkit (IGSTK) as a library that provided the basic components of the system for location, tracking, and registration. The electromagnetic tracking device was used to measure the real-time position of surgical tools and fiducials attached to the patient's anatomy. IGSTK was integrated into MITK; at the same time, the compatibility and the stability of this system were emphasized. Experiments showed that an integrated system of the image-guided surgery navigation system could be developed in 2 months. The integration of IGSTK into MITK is feasible. Several techniques for 3D reconstruction, geometric analysis, mesh generation, and surface data analysis for medical image analysis of MITK can connect with the techniques for location, tracking, and registration of IGSTK. This integration of advanced modalities can decrease software development time and emphasize the precision, safety, and robustness of the image-guided surgery navigation system.