280 research outputs found

    In Situ Transmission Electron Microscopy for Electronics

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    Electronic devices are strongly influenced by their microstructures. In situ transmission electron microscopy (in situ TEM) with capability to measure electrical properties is an effective method to dynamically correlate electric properties with microstructures. We have developed tools and in situ TEM experimental procedures for measuring electronic devices, including TEM sample holders and sample preparation methods. The method was used to study metallic nanowire by electromigration, magnetoresistance of a ferromagnetic device, conductance quantization of a metallic nanowire, single electron tunnelling, and operation details of resistive random access memories (ReRAM)

    Bezier Simplex Fitting: Describing Pareto Fronts of Simplicial Problems with Small Samples in Multi-objective Optimization

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    Multi-objective optimization problems require simultaneously optimizing two or more objective functions. Many studies have reported that the solution set of an M-objective optimization problem often forms an (M-1)-dimensional topological simplex (a curved line for M=2, a curved triangle for M=3, a curved tetrahedron for M=4, etc.). Since the dimensionality of the solution set increases as the number of objectives grows, an exponentially large sample size is needed to cover the solution set. To reduce the required sample size, this paper proposes a Bezier simplex model and its fitting algorithm. These techniques can exploit the simplex structure of the solution set and decompose a high-dimensional surface fitting task into a sequence of low-dimensional ones. An approximation theorem of Bezier simplices is proven. Numerical experiments with synthetic and real-world optimization problems demonstrate that the proposed method achieves an accurate approximation of high-dimensional solution sets with small samples. In practice, such an approximation will be conducted in the post-optimization process and enable a better trade-off analysis.Comment: To appear in AAAI 201

    Relationship Between Age and Frequency of Side Effects Associated with Postoperative Analgesia

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    Study Objective: Although patient-controlled analgesia (PCA) is a valid analgesic method, it is necessary to pay attention to associated side effects, especially in elderly patients. It is unclear whether the incidence of side effects increases with age. In this study, we examined the incidence of side effects by age to confirm whether the frequency of side effects varies depending on age group. Patients: Patients who underwent gastroenterological surgery at Hiroshima University Hospital between 2009 and 2013 and received postoperative analgesia using PCA [either epidural PCA (PCEA) or intravenous PCA (IVPCA) were included]. Measurements: The degree of pain using the visual analog scale, number of PCA requests, and frequency of side effects, including nausea, vomiting, pruritus, urinary disturbance, drowsiness, low blood pressure, delirium, and respiratory depression, was determined from PCA records. Main Results: A total of 2,881 patients were enrolled and categorized into PCEA (n = 1,965) or IVPCA (n = 916) group based on postoperative analgesia. The incidence of delirium significantly increased with age in both groups (P < 0.001). In the PCEA group, the incidence of nausea, vomiting, and itching decreased, whereas that of hypotension significantly increased with age. Visual analog scale scores both at rest and during activity on postoperative day 2 were not correlated with age in either group. There was a significant negative correlation with age in both groups for the number of PCA requests on postoperative day 2. Conclusions: The incidence of postoperative delirium increases with age regardless of pain relief method. Side effects related to postoperative analgesia are not necessarily more likely to occur with age

    Autosynchronized systolic unloading during left ventricular assist with a centrifugal pump

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    AbstractObjectives: The purpose of this study was to investigate how the inflow cannulation site of the left ventricular assist system with a centrifugal pump would influence cardiac function on failing heart models. Methods: In 10 sheep, a left ventricular assist system was instituted by an outflow cannula in the descending aorta, two inflow cannulas in the left atrium and the left ventricle, and connecting those cannulas to a magnetically suspended centrifugal pump. A conductance catheter and a tipped micromanometer for monitoring the pressure-volume loop were also inserted into the left ventricle. Myocardial oxygen consumption was directly measured. Heart failure was induced by injection of microspheres into the left main coronary artery. The assist rate was varied from 0% to 100% at each inflow cannulation site. Results: The pump flow with left ventricular cannulation increased during the systolic phase and decreased during the diastolic phase, whereas it was constant with left atrial cannulation. Ejection fraction with left atrial cannulation decreased as the assist rate increased, whereas that with left ventricular cannulation was maintained up to 75% assist. The external work with left atrial cannulation decreased gradually as the assist rate increased, whereas the external work with left ventricular cannulation did not decrease until the assist rate reached 75%. The myocardial oxygen consumption in both cannulations decreased proportionally as the assist rate increased; they were significantly less with left ventricular cannulation at the 100% assist rate than with left atrial cannulation. Conclusion: Left ventricular cannulation during left ventricular assistance maintains ejection fraction and effectively reduces oxygen consumption.J Thorac Cardiovasc Surg 2003;125:353-6

    Suppression Effect of Radiated Emission from Twisted Pair Wires with Ferrite Core

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    Telecommunications signal emissions from unshielded twisted pair (UTP) cable should be suppressed to maintain EMC of telecommunication systems. This paper describes the suppression effects of the ferrite cores which are installed on the UTP cable. Twisted pair wire with ferrite core was modeled by 4-port network to evaluate suppression effect. Parameters of the networks which are constructed with UTP cable or ferrite core with wires were determined from calculation and measurement. Using the networks, the common-mode current distribution on the cable was obtained, and emitted electric field strength was calculated from the distribution. The emission suppression effect was obtained from the result, and the results were almost agreed with measured value. The calculation results suggest that 1) the ferrite cores should be arranged side by side, 2) these should be placed near the signal supply end of the cable.2003 IEEE Symposium on Electromagnetic Compatibility, August 18-22, 2003, Boston, MA, US

    Composition and Monthly Changes of the Volatile Constituents in the Sour Hetsuka-daidai Citrus Peel

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    Sour citrus are prized for their flavor and fragrance. This work identified the components of the peel oil of Hetsuka-daidai (Citrus sp. hetsukadaidai), a special sour citrus that is native to the southern part of the Osumi peninsula, Kagoshima, Japan. These compounds were compared to those identified from the peels of six other major sour citrus: lime (Citrus latifolia), lemon (Citrus limon), Yuzu (Citrus junos), Kabusu (Citrus aurantium), Kabosu (Citrus sphaerocarpa), and Sudachi (Citrus sudachi). Peel oil contents were analyzed for the duration of four months during harvest season to investigate the differences in peel oil/ fragrance during ripening. These results could facilitate the development of preferred flavor and scent profiles using local species
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