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931.
The corrosion resistance and conduction properties of polyaniline (PANi)-coated 316L stainless steel were improved by the thermal treatment. Electrochemical analyses of the PANi specimens demonstrated excellent corrosion resistance with high protection efficiency (?96.21%) and charge transfer resistance, as well as a very low corrosion current density (<1 μA/cm2). In addition, it also performed better conductive properties due to lower contact and surface resistance (<5 Ω cm2), comparing with untreated specimens. These were attributed to the presence of the interaction of the carbonyl group with the NH group in PANi as a physical barrier layer, which provides passivity protection in polymer coatings. 相似文献
932.
Young-Taek Lee Jaechun Lee Sangwook Nam 《Microwave and Wireless Components Letters, IEEE》2005,15(1):39-41
This letter presents a new method to reduce the phase noise in oscillator based on the loaded Q improvement approach. A hairpin resonator is weakly coupled to the two microstrip lines to improve the loaded Q of it and the dual feedback topology is used to enable the start-up oscillation condition to be satisfied. The high loaded Q property of the resonator in the proposed oscillator circuit is analyzed using the CAD simulation. For comparison the phase noise performances of the conventional hairpin resonator oscillator and the oscillator using the dual feedback are measured. Measurements show that the oscillator using the dual feedback exhibits a low phase noise performance of -109.1 dBc/Hz at 100-kHz offset at 10 GHz, which is reduced by about 10 dB compared to that of the conventional one. 相似文献
933.
Jin Ha Lee Seong Hee Nam Hyen Joung Park Young-Min Kim Nahyun Kim Ghahyun Kim Eun-Seong Seo Seong-Soo Kang Doman Kim 《Food science and biotechnology》2010,19(3):757-762
Appreciably elevated levels of dextranase from Arthrobacter oxydans (AODex) isolated from sugar-cane farm soil was resulted from the culture on the Luria-Bertani (LB) medium containing 1%(w/v)
soluble starch, glycerol, or dextran. The responsible gene (aodex) was cloned, its nucleotide sequence was determined, and expression of the encoded protein was achieved in Escherichia coli. An open reading frame was composed of 1,863 bp putatively encoding a 68.3 kDa protein. Recombinant A. oxydans dextranase (rAODex) was purified about 16 fold by nickel-nitrilotriacetic acid affinity column chromatography; K
m value for dextran T2000 was 0.85 mg/mL (w/v). AODex treatment of stale sugar cane juice resulted in a yield of square and
light-colored sugar crystals. 相似文献
934.
The effect of iron(III) p-toluenesulfonate hexahydrate (Fe(PTS)3) concentration on the formation and patternability of poly(3,4ethylenedioxythiophene) (PEDOT) films on (3-aminopropyl)trimethoxysilane (APS) monolayer was investigated. Low deposition rate yielded highly conductive and very smooth PEDOT films. However, the spin-coated oxidants in low Fe(PTS)3 concentrations were susceptible to moistures, leading to the poorly patterned PEDOT films. Increasing Fe(PTS)3 concentration enabled the fine patterning of the films. The fabricated thin film transistors with PEDOT electrodes formed on 30 wt.% Fe(PTS)3 revealed the saturation mobility of 0.16 cm2/V s and subthreshold slope of 0.5 V/decade. The obtained low contact resistance was 12 kΩ cm, possibly due to the negligible interface morphological discontinuity at the pentacene-PEDOT interface. 相似文献
935.
The effects of deformation temperatures and post-deformation annealing on mechanical properties, in conjunction with microstructural
evolution in the 5052 Al alloy, were investigated. The combination of cryogenic-rolling with warm-rolling effectively increased
tensile strength and yield strength without the decrease of ductility through the formation of ultra-fine grains with dynamic
recovery in the 5052 Al alloy. And static annealing, as a post-heat treatment, enhanced the ductility. Therefore, ultra-fine
grained 5052 Al alloy with high strength and a moderate level of ductility could be made by the combination of cryogenic-rolling
with warm-rolling and the additional static annealing process. 相似文献
936.
Jae-Sang Park Sung Nam Jung Soo Hyung Park Yung Hoon Yu 《Journal of Mechanical Science and Technology》2010,24(8):1583-1594
In this work, the Blade Vortex Interaction (BVI) airloads characteristic for a rotor in descending flight condition is investigated
using a nonlinear flexible multibody dynamics analysis code DYMORE. A free vortex wake model is incorporated into the comprehensive
analysis system and improvement of airloads prediction as well as collective and cyclic pitch control settings is obtained
over the finite-state dynamic inflow model that is adopted in the conventional DYMORE analysis. The three test conditions
in the HART (Higher harmonic control Aeroacoustic Rotor Test) II are considered to illustrate the present investigation. It
is found that the BVI airloads characteristic is significantly influenced by the higher harmonic pitch control inputs. The
influence of BVI oscillatory peaks along with the miss-distance between the blade and the vortices is studied in detail to
identify the mechanism of reducing noise and vibration in the HART II experiment. 相似文献
937.
Mechanical properties and material mixing patterns of friction stir spot welded (FSSW) joints of dissimilar aluminum alloys were investigated.Two aluminum alloys typically used in automotive applications,5052-H32 and 6061-T6,were selected.During the experiment,the process parameters including the z-axis force and torque histories were measured as a function of the tool displacement.The mechanical properties were investigated by microhardness measurements of the joint,and the material mixing in the stir zone was investigated by EPMA.The experimental results illustrate different process parameter histories,material mixing in the stir zone and material properties including microhardness distributions for FSSW joints of dissimilar aluminum alloys,likely due to different mechanical behaviors of the selected aluminum alloys in the FSSW process temperature range. 相似文献
938.
Young‐Han Nam Lingjia Liu Jianzhong Zhang 《International Journal of Communication Systems》2014,27(10):1616-1625
The Long Term Evolution‐Advanced (LTE‐A) system is currently under development to allow for significantly higher spectral efficiency and data throughput than the LTE systems. In a wireless system based on orthogonal frequency division multiplexing with frequency reuse factor one, the achievable cell spectral efficiency is often limited by the inter‐cell interference or coverage shortage of base stations. In LTE‐A, coordinated multi‐point transmission/reception (a.k.a. multi‐cell MIMO or base station cooperation) and relaying technologies are being introduced to clear these major performance hurdles. In this paper, cooperative communication technologies being discussed in LTE‐A systems are presented, together with considerations on system design. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
939.
The coefficient of thermal expansion (CTE) of Al-based metal matrix composites containing 70 vol.% SiC particles (AlSiC) has been measured based on the length change from room temperature (RT) to 500 °C. In the present work, the instantaneous CTE(T) of AlSiC is studied by thermo-elastic models and micromechanical simulation using finite element analysis in order to explain abnormalities observed experimentally. The CTE(T) is predicted according to analytical thermo-elastic models of Kerner, Schapery and Turner. The CTE(T) is modelled for heating and cooling cycles from 20 °C to 500 °C considering the effects of microscopic voids and phase connectivity. The finite element analysis is based on a two-dimensional unit cell model comparing between generalized plane strain and plane stress formulations. The thermal expansion behaviour is strongly influenced by the presence of voids and confirms qualitatively that they cause the experimentally observed decrease of the CTE(T) above 250 °C. 相似文献
940.
Choi Eun-Ju Kim Eun-Kyung Jeoung Nam Ho Kim Sang-Hyun 《Food science and biotechnology》2016,25(1):119-124
In this study, we investigated the effects of silymarin (SM) on gluconeogenesis during exercise in rats. After 4 weeks of exercise, blood samples, liver, and skeletal muscle tissues were collected, and the levels of triglycerides (TG), lactate, peroxisome proliferator activated receptor gamma (PPARγ), phosphoenol pyruvate carboxykinase (PEPCK), pyruvate dehydrogenase kinase 4 (PDK4), and phosphorylated 5-AMP activated protein kinase (AMPK) were measured. The TG and lactate level of the serum were reduced. In addition, the expression of Akt, PEPCK, and PPARγ in liver was decreased as well as the expression of AMPK in muscle. On the contrary, the level of PDK4 in muscle was increased. These results showed that that administration of SM ameliorated exerciseinduced gluconeogenesis and β-oxidation through the regulation of PPARγ, PEPCK, and PDK4. Thus, intake of SM during exercise may improve endurance by modulating of the metabolism of glucose, lipids, and lactate. 相似文献