2,821 research outputs found

    Ultrahigh areal number density solid-state on-chip microsupercapacitors via electrohydrodynamic jet printing

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    Microsupercapacitors (MSCs) have garnered considerable attention as a promising power source for microelectronics and miniaturized portable/wearable devices. However, their practical application has been hindered by the manufacturing complexity and dimensional limits. Here, we develop a new class of ultrahigh areal number density solid-state MSCs (UHD SS-MSCs) on a chip via electrohydrodynamic (EHD) jet printing. This is, to the best of our knowledge, the first study to exploit EHD jet printing in the MSCs. The activated carbon-based electrode inks are EHD jet-printed, creating interdigitated electrodes with fine feature sizes. Subsequently, a drying-free, ultraviolet-cured solid-state gel electrolyte is introduced to ensure electrochemical isolation between the SS-MSCs, enabling dense SS-MSC integration with on-demand (in-series/in-parallel) cell connection on a chip. The resulting on-chip UHD SS-MSCs exhibit exceptional areal number density [36 unit cells integrated on a chip (area = 8.0 mm x 8.2 mm), 54.9 cells cm(-2)] and areal operating voltage (65.9 V cm(-2))

    Position and Thickness Optimization of Ribs for Ventilation Covering Using the Micro Genetic Algorithm with an Interpolated Smooth Objective Function

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    Structures with supporting ribs are adopted in many fields of engineering. These ribs are attached to the main plate or shell to increase stiffness and reduce the stresses of a structure. Currently, much research in structural optimization has been devoted to size or thickness optimizations. In this study, the discrete positions of the ribs of a structure are optimized in addition to their thicknesses. The objective function, which is the total weight of a structure, is a continuous function with respect to the thickness of the ribs. However, it is a stepwise function of a dimensionless variable, which represents the set of positions of the ribs. Because of this stepwise objective function, the gradient method of optimization is not applicable. Therefore, we applied the micro genetic algorithm (MGA), which does not need derivatives of the objective function. To accelerate the rate of convergence, the stepwise objective function is interpolated to a smooth artificial objective function that does not alter the optimal solution

    Arctic-North Pacific Coupled Impacts on the Late Autumn Cold in North America

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    The Pacific Decadal Oscillation (PDO) is known to bring an anomalously cold (warm) period to southeastern (northwestern) North America during the cold season of its positive phase through a Rossby wave linkage. This study provides evidence that the remote connection between the North Pacific and the downstream temperature over central North America is strengthened by the warm arctic conditions over the Chukchi and East Siberian Sea, especially in the late autumn season. The modulation effect of the Arctic manifests itself as an altered Rossby wave response to a transient vorticity forcing that results from an equatorward storm track shift, which is induced collaboratively by the PDO and the warm Arctic. This observational finding is supported by two independent modeling experiments: 1) an idealized coupled GCM experiment being nudged toward the warm arctic surface condition and 2) a simple stationary wave model (SWM) experiment forced by transient eddy forcing

    Effects of Particle Sizes on Sintering Behavior of 316L Stainless Steel Powder

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    In rapidly evolving powder injection molding technology, the wide prevalence of various microstructures demands the powders of smaller particle sizes. The effects of particle size on the sintering behavior are critical to not only shape retention of microstructure but also its mechanical properties. This study investigates the effects of three different particle sizes on the sintering behavior of the 316L stainless steel (STS316L) samples, prepared by powder injection molding, via the dilatometry experiments. For this purpose, the STS316L powders of three different mean particle sizes, i.e., 2.97, 4.16, and 8.04 mu m, were produced for STS316L. The samples for the dilatometry test were prepared through powder-binder mixing, injection molding, and solvent and thermal debinding. Dilatometry experiments were carried out with the samples in a H-2 atmosphere at three different heating rates of 3, 6, and 10 K/min. The shrinkage data obtained by dilatometry experiments was collected and analyzed to help understand the densification and the sintering behaviors in terms of particles size and heating rate. The master sintering curve (MSC) model was used to quantify the effects of particle sizes. In addition, we investigated the microstructure evolutions in terms of particles sizes.open1186sciescopu

    Fabrication of Nonenzymatic Glucose Sensors Based on Multiwalled Carbon Nanotubes with Bimetallic Pt-M (M = Ru and Sn) Catalysts by Radiolytic Deposition

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    Nonenzymatic glucose sensors employing multiwalled carbon nanotubes (MWNTs) with highly dispersed Pt-M (M = Ru and Sn) nanoparticles (Pt-M@PVP-MWNTs) were fabricated by radiolytic deposition. The Pt-M nanoparticles on the MWNTs were characterized by transmittance electron microscopy, elemental analysis, and X-ray diffraction. They were found to be well dispersed and to exhibit alloy properties on the MWNT support. Electrochemical testing showed that these nonenzymatic sensors had larger currents (mA) than that of a bare glassy carbon (GC) electrode and one modified with MWNTs. The sensitivity (A mM−1), linear range (mM), and detection limit (mM) (S/N = 3) of the glucose sensor with the Pt-Ru catalyst in NaOH electrolyte were determined as 18.0, 1.0–2.5, 0.7, respectively. The corresponding data of the sensor with Pt-Sn catalyst were 889.0, 1.00–3.00, and 0.3, respectively. In addition, these non-enzymatic sensors can effectively avoid interference arising from the oxidation of the common interfering species ascorbic acid and uric acid in NaOH electrolyte. The experimental results show that such sensors can be applied in the detection of glucose in commercial red wine samples

    Clinical Manifestations of Recurrent Parotid Pleomorphic Adenoma

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    Objectives. This study was undertaken to confirm the clinical characteristics of recurrent pleomorphic adenoma (RPA), and to identify those factors that affect the development of malignant transformation (MT) from RPA. Methods. The medical records of 270 patients, who were operated upon for parotid PA, were retrospectively reviewed. The pathologic specimens of a selected series of 23 patients were reviewed for histologic subtype and microscopic multi-nodularity. Results. Mean age of initial operation in RPA without MT (RPA(-MT)) group was significantly lower than that of primary PA group. Mean age of the revision operation in RPA with MT (RPA(+MT)) group was significantly greater than that of RPA(-MT) group. Mean interval from operation to recurrence shortened after each revision operation. The risk of MT and additional recurrence increased significantly with recurrence. In RPA(-MT) group tumor recurrence occurred in 21.4% of patients despite a clear resection margin. Conclusion. The risk factors for MT may be an age of over 45 yr and multiple recurrences. However, younger patients are more at risk of recurrence. A clear resection margin cannot guarantee a cure in RPA, and it seems that parotid pleomorphic adenomas slowly gain malignant characteristics after repeated recurrences.SUH MW, 2005, KOREAN J HEAD NECK O, V21, P146HANNA EY, 2005, CUMMINGS OTOLARYNGOL, P1348Ghosh S, 2003, CLIN OTOLARYNGOL, V28, P262Glas AS, 2002, CANCER, V94, P2211, DOI 10.1002/cncr.10445Glas AS, 2001, HEAD NECK-J SCI SPEC, V23, P311BRADLEY PJ, 2001, CURR OPIN OTOLARYNGO, V9, P100Carew JF, 1999, OTOLARYNG HEAD NECK, V121, P539Junquera L, 1999, HEAD NECK-J SCI SPEC, V21, P652Hancock BD, 1999, ANN ROY COLL SURG, V81, P299Bankamp DG, 1999, LARYNGO RHINO OTOL, V78, P77Hoorweg JJ, 1998, EUR J SURG ONCOL, V24, P452Henriksson G, 1998, CANCER, V82, P617Laskawi R, 1998, BRIT J ORAL MAX SURG, V36, P48Klijanienko J, 1997, HEAD NECK-J SCI SPEC, V19, P629Leverstein H, 1997, EUR ARCH OTO-RHINO-L, V254, P313SunardhiWidyaputra S, 1995, PATHOL RES PRACT, V191, P1186PHILLIPS PP, 1995, ANN OTO RHINOL LARYN, V104, P100BUCHMAN C, 1994, LARYNGOSCOPE, V104, P1231NATVIG K, 1994, HEAD NECK-J SCI SPEC, V16, P213JACKSON SR, 1993, J LARYNGOL OTOL, V107, P546MCGREGOR AD, 1988, BRIT J PLAST SURG, V41, P177FEE WE, 1978, LARYNGOSCOPE, V88, P265SEIFERT G, 1976, HNO, V24, P415NAEIM F, 1976, ARCH PATHOL LAB MED, V100, P271FRAZELL EL, 1954, CANCER, V7, P637

    Mechanical Stimulation of the HT7 Acupuncture Point to Reduce Ethanol Self-Administration in Rats

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    Background. Alcoholism, which is a disabling addiction disorder, is a major public health problem worldwide. The present study was designed to determine whether the application of acupuncture at the Shenmen (HT7) point suppresses voluntary alcohol consumption in addicted rats and whether this suppressive effect is potentiated by the administration of naltrexone. Methods. Rats were initially trained to self-administer a sucrose solution by operating a lever. A mechanical acupuncture instrument (MAI) for objective mechanical stimulation was used on rats whose baseline response had been determined. In addition, the effect of HT7 acupuncture on beta-endorphin concentration and ethanol intake via naltrexone were investigated in different groups. Results. We found that ethanol intake and beta-endorphin level in rats being treated with the MAI at the HT7 point reduced significantly. The treatment of naltrexone at high doses reduced the ethanol intake and low-dose injection of naltrexone in conjunction with the MAI also suppressed ethanol intake. Conclusions. The results of the current study indicate that using the MAI at the HT7 point effectively reduces ethanol consumption in rats. Furthermore, the coadministration of the MAI and a low dose of naltrexone can produce some more potent reducing effect of ethanol intake than can acupuncture alone
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