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排序方式: 共有1401条查询结果,搜索用时 15 毫秒
31.
K. Kakushima K. Okamoto M. Kouda T. Kawanago P. Ahmet K. Tsutsui T. Hattori 《Microelectronics Reliability》2010,50(3):356-359
The chemical bonding states and electrical characteristics of SrO capped La2O3/CeOx gate dielectric have been examined. Angle-resolved X-ray photoelectron spectroscopy measurement has revealed that Sr atoms diffuse into silicate layer to form SrLa-silicate after annealing. Owing to the incorporation of Sr atoms into silicate layer, a transistor operation with an equivalent oxide thickness (EOT) below 0.5 nm has been demonstrated. A strongly degraded effective electron mobility of 78 cm2/V s at 1 MV/cm has been obtained, which fit well with the general trend in small EOT range below 1 nm. Although process optimization is needed to improve the performance of transistors, Sr capping technique can be useful for EOT scaling. 相似文献
32.
Mehmet Ali Yurdusev Ahmet Ali Kumanlıoğlu Yüksel Abalı M. Sadrettin Zeybek 《Construction and Building Materials》2009,23(5):1871-1877
In this study, usability of wastes produced in phosphoric acid plants in structural brick manufacture has been investigated. There are several parameters involved in using these wastes in brick production namely the rate of added waste, firing speed and firing temperature. The performance of these parameters can be measured by several criteria such as natural drying shortening, water absorption and weight loss. Therefore, so many experiments are needed to investigate the effects of these parameters on the bricks produced with these wastes. The result of a series of experiments were utilized to achieve this end. The results have shown that the industrial wastes considered improve the performance of the bricks in terms of the criteria mentioned above. However, the results have also shown that further investigations are needed to explore the effects of interim values on the performance of the bricks. To achieve that end, a neural experimental study is adopted. For this purpose, the results of the experiments conducted were used to construct an artificial neural network. The trained and tested network was then used to check the effects of 280 different combinations for each type of material mixtures mentioned. The outcome of these artificial tests have provided the optimal values for the waste addition rate, firing speed and firing temperature based on the four criteria mentioned previously. 相似文献
33.
Optimum performance of a heat engine‐driven combined vapour compression–absorption–ejector heat pump
Optimum performance of an endoreversible heat engine‐driven heat pump cycle, based on a combination of an absorption cycle with a vapour and ejector compression cycles is investigated. This combination increases the performance of the conventional ejector and absorption cycles and provides high performance for heating. The analysis show that the combined heat pump cycle has a significant increase in system performance over the heat engine‐driven vapour compression or absorption heat pump cycle and heat engine‐driven combined vapour compression and absorption heat pump cycle. Copyright © 2000 John Wiley & Sons, Ltd. 相似文献
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36.
Ahmet Capoglu 《Journal of the European Ceramic Society》2011,31(3):321-329
This study was carried out to characterize the properties of a novel low-clay translucent whiteware suitable for daily use. The low-clay whiteware is produced from coarsely and finely milled prefired materials of the same composition plus a small amount of clay. It consists of anorthite (CaO·Al2O3·2SiO2) and mullite (3Al2O3·2SiO2) crystalline phases and a glassy phase with high crystalline to glassy phase ratio. The development of needle shaped long mullite crystals that were forming three dimensional interlocking network had significant effect on the elimination of pyroplastic deformation during glaze firing. Typical flexural strength and fracture toughness values were ∼110 MPa and ∼1.85 MPam1/2, respectively. The low-clay whiteware had relatively low (4.6 × 10−6/°C) thermal expansion coefficient which made possible to glaze the whiteware with a typical hard porcelain glaze. A continuous interface layer was produced between the whiteware and the glaze and no crack was present through layer because of expansion mismatch. 相似文献
37.
In this study, a novel azocalix[4]arene derivative, 5,11,17-tris[(1-naphtyl)azo]-25,26,27,28-tetrahydroxy-calix[4]arene (NAC4) bearing napthyl groups on the upper rim was synthesized. Its complexation behavior for alkali, alkaline-earth and various heavy metal ions (Li+, Na+, K+, Rb+, Cs+, Mg2+, Ca2+, Sr2+, Ba2+, Pb2+, Hg2+, Ni2+, Cd2+, Cu2+, Zn2+, Co2+, Fe2+, Cr3+, Ag+) was investigated by spectroscopic and voltammetric methods. This chemosensor exhibits decreased absorbance in the presence of Hg2+ and a unique absorbance quenching effect only for Cr3+. In addition, a new absorption band centered at 565 nm with the formation of the 1:1 host–guest complex (Cr3+-NAC4) was observed in the case of Cr3+, leading to an obvious color change from light orange to dark lilac. In voltammetric experiments, Cr3+ ions decreased voltammetric peaks of NAC4, whereas no significant changes occurred in the presence of the other metal ions. The Benesi–Hildebrand method was used to determine a logarithmic value of 3.76 for the association constant of the complex between Cr3+ and NAC4. 相似文献
38.
Süleyman Köytepe Maruf Hurşit Demirel Ahmet Gültek Turgay Seçkin 《Polymer International》2014,63(4):778-787
In this study, novel metallo‐supramolecular materials based on terpyridine‐functionalized polyhedral silsesquioxane were synthesized from 4′‐chloro‐2,2′:6′,2″‐terpyridine and amino‐group‐functionalized polyhedral oligomeric silsesquioxane. The obtained terpyridine‐functionalized polyhedral silsesquioxanes were converted to metallo‐supramolecular hybrid materials by coordination polycondensation reaction with Co(II) or Cu(II) ions. The supramolecular polymers created were characterized by means of structure, morphology and stimuli‐responsive performance employing scanning electron microscopy, amperometric techniques and UV–visible and Fourier transform IR spectroscopy. UV?visible and cyclic voltammetry studies showed that both the optical and electrochemical properties of metallo‐supramolecular materials are affected by the substituent at the pyridine periphery. The supramolecular polymers obtained exhibited electrochromism during the oxidation processes of cyclic voltammogram studies. As a result, these terpyridine‐functionalized polyhedral silsesquioxanes are good candidates for electronic, opto‐electronic and photovoltaic applications as smart stimuli‐responsive materials. © 2013 Society of Chemical Industry 相似文献
39.
Erkan Ertürk Mustaf Ali Tezeren Tahir Tilki Tuba Erdogan Ahmet C Gren 《Polymer International》2012,61(5):795-799
The readily available mixed‐valent iron trifluoroacetate complex [Fe2IIIFeII(µ3‐O)(O2CCF3)6(H2O)3] is an effective catalyst for the polymerization of epoxides. A very small amount of the catalyst (1.0–0.01 mol%) could initiate the polymerization of cyclohexene oxide, cyclopentene oxide and epichlorohydrin. Based on quantitative end‐group analysis by 19F NMR spectroscopy, a Lewis acid (LA⊕) catalyzed anionic reaction mechanism is proposed. Copyright © 2012 Society of Chemical Industry 相似文献
40.
Tuncay Tun? ?brahim Uslu ?enol Durmu?o?lu Selda Keskin Arda Aytimur Ahmet Akdemir 《Journal of Inorganic and Organometallic Polymers and Materials》2012,22(1):105-111
In this study, boron doped and undoped poly (vinyl) alcohol/bismuth–gadolina acetate (PVA/Bi–Gd) nanofibers were prepared
using electrospinning technique then calcinated at 800 °C for 2 h. The originality of this study is the addition of boron
to metal acetates. The effects of boron doping were investigated in terms of solution properties, morphological changes and
thermal characteristics. The characteristics of the fibers were investigated with FT-IR, XRD, SEM and BET. The addition of
boron did not only increase the thermal stability of the fibers, but also their diameters, which yielded stronger fibers.
XRD analyses showed that boron doping increased the peak intensities and indicated that the boron doping enhanced the crystallite
size. Moreover, no shifts were noticed in diffraction angles for boron doped and undoped samples. Therefore, boron doping
did not significantly alter the lattice spacing. The SEM micrograph of the fibers showed that the addition of boron resulted
in the formation of cross-linked bright-surfaced fibers. The average fiber diameter for boron doped and undoped fiber mats
were 204 and 123 nm, respectively. Also, grain diameters of boron doped and undoped nanocrystalline sintered powders were
measured as 140 and 118 nm, respectively. The BET results showed that boron undoped and doped Bi2O3–La2O3 nanocrystalline powder ceramic structures sintered at 800 °C have surface areas of 59.72 and 39.80 m2/g, respectively. 相似文献