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51.
A new oxide-ion conductor of Aurivillius-type structure, namely BISRVOX (Bi2SrxV1−xO5.5-(3x/2)-δ, 0≤x≤0.20), was successively synthesized by the microwave-assisted solid state reaction. 25 min of microwave irradiation was found to be quite sufficient to ensure the completion of reaction. Powder X-ray diffraction and differential thermal analysis showed better structural properties for the microwave-prepared samples compared to those obtained from the conventional solid synthesis route. Interestingly, the highly conducting γ-phase was effectively stabilized for x≥0.10. AC impedance spectroscopy evidenced the superiority of the microwave heating over conventional solid synthesis routes in exhibiting high oxide-ion performance. 相似文献
52.
Daniel Ayuk Mbi Egbe Le Huong Nguyen Kathy Schmidtke Andreas Wild Christoph Sieber Serap Guenes Niyazi Serdar Sariciftci 《Journal of polymer science. Part A, Polymer chemistry》2007,45(9):1619-1631
This contribution presents the synthesis and properties of four thiophene‐containing poly(‐p‐arylene‐ethynylene)/poly(‐p‐arylene‐vinylene)s, PIa‐b and PIIa‐b , whose repeating units (RU) consist either of 1:2 or 2:2 triple bond/double bond ratio, and which bear linear alkoxy side chains not longer than octyloxy and branched 2‐ethylhexyloxy. PIa‐b and PIIa‐b exhibit similar absorption and emission behaviour in dilute solution (λa = 483–486 nm, λe = 540 nm) as well as in solid state (λa = 500, 530 nm, λe = 560 nm), whereby slightly higher fluorescence quantum yields (Φf) were obtained for PI than for PII systems, as a result of higher number of thiophene units within the RU of PII . An enhancement of the Φf‐value from 0% to 3% is obtained after replacing linear octadecyloxy in PIIc‐e by bulky branched 2‐ethylhexyloxy in PIIa‐b . Nonoptimized solar cells of configuration ITO/PEDOT:PSS/polymer: PCBM (1:3 weight ratio)/LiF/Al show open circuit voltages as high as 900 mV for PIa‐b and 800 mV for PIIa‐b . Reducing the size of the side chain from R = 2‐ethylhexyl in PIa to R = methyl in PIb leads to a significant increase of the short circuit current, I SC, from ca. 2.5 mA to ca. 3.7 mA and consequently to an enhancement of the energy conversion efficiency, ηAM1.5, from ca. 1.2% to ca. 1.7%. This is due to an extended donor‐acceptor interfacial area, as evidenced by AFM topology pictures showing smaller nanoscale clusters size in PIb than in PIa active layer. The same change led to minimal effect in PII systems. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1619–1631, 2007 相似文献
53.
Photoinduced Energy Transfer from Poly(N‐vinylcarbazole) to Tricarbonylchloro‐(2,2′‐bipyridyl)rhenium(I)
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Dr. Engelbert Portenkirchner Dogukan Apaydin Gottfried Aufischer Dr. Marek Havlicek Prof. Matthew White Prof. Markus Clark Scharber Prof. Niyazi Serdar Sariciftci 《Chemphyschem》2014,15(16):3634-3638
This work investigates the photoinduced energy transfer from poly(N‐vinylcarbazole) (PVK), as a donor material, to fac‐(2,2′‐bipyridyl)Re(CO)3Cl, as a catalyst acceptor, for its potential application towards CO2 reduction. Photoluminescence quenching experiments reveal dynamic quenching through resonance energy transfer in solid donor/acceptor mixtures and in solid/liquid systems. The bimolecular reaction rate constant at solution–film interfaces for the elementary reaction of the excited state with the quencher material could be determined as 8.8(±1.4)×1011 L mol?1 s?1 by using Stern–Volmer analysis. This work shows that PVK is an effective and cheap absorber material that can act efficiently as a redox photosensitizer in combination with fac‐(2,2′‐bipyridyl)Re(CO)3Cl as a catalyst acceptor, which might lead to possible applications in photocatalytic CO2 reduction. 相似文献
54.
Samples of Bi4Ca x V2? x O11?(3 x /2)?δ in the composition range 0.07 ≤ x ≤ 0.30 were prepared by conventional solid state reactions. The stability of different phases as a function of composition was analysed by X-ray powder diffraction, FT-IR spectra, differential thermal analysis and AC impedance spectroscopy. For the compositions x ≤ 0.10, monoclinic α-phase structure is retained at room temperature. For x = 0.13, orthorhombic β-phase is observed, whereas for x ≥ 0.17, high O2?conducting tetragonal γ-phase is stabilised. However, the highest ionic conductivity σ300°C = 3.27 × 10?4 S cm?1 was observed for x = 0.17. This higher value of conductivity of the substituted compound as compared to the parent compound can be attributed to the increased oxygen ion vacancies generated as a result of cation doping. AC impedance spectroscopy reveals the fact that this ionic conductivity is mainly due to the grain contribution. 相似文献
55.
Samples of bismuth lead vanadium oxide (BIPBVOX) (Bi2V1–xPbxO5.5–x/2) singly substituted system in the composition range 0.05 ≤ x ≤ 0.20 were prepared by sol–gel synthesis route. Structural investigations were carried out by using a combination of differential thermal analysis (DTA) and powder X-ray diffraction (PXRD) technique. Energy dispersive X-ray spectroscopy analysis (EDXA) of doped samples was carried out to predict the sample purity and doping concentration. Transitions, α?β, β?γ and γ′?γ were detected by XRD, DTA and variation in the Arrhenius plots of conductivity. The ionic conductivity was measured by AC impedance spectroscopy. The solid solutions with composition x ≤ 0.07 undergo α?β phase transition, at 329 °C and β?γ phase transition at 419 °C. The highly conducting γ′-phase was effectively stabilized at room temperature for compositions with x ≥ 0.17 whose thermal stability increases with Pb content. At 300 °C, the highest value of conductivity 6.234 × 10?5 S cm?1 was obtained for composition x = 0.15 and at 600 °C the highest value of conductivity 0.65 S cm?1 is observed for x = 0.17. AC impedance plots reveal that the conductivity is mainly due to the grain contribution to oxide ion conductivity. 相似文献
56.
Jan Richtar Lucia Ivanova Dong Ryeol Whang Cigdem Yumusak Dominik Wielend Martin Weiter Markus Clark Scharber Alexander Kovalenko Niyazi Serdar Sariciftci Jozef Krajcovic 《Molecules (Basel, Switzerland)》2021,26(1)
A series of novel soluble nature-inspired flavin derivatives substituted with short butyl and bulky ethyl-adamantyl alkyl groups was prepared via simple and straightforward synthetic approach with moderate to good yields. The comprehensive characterization of the materials, to assess their application potential, has demonstrated that the modification of the conjugated flavin core enables delicate tuning of the absorption and emission properties, optical bandgap, frontier molecular orbital energies, melting points, and thermal stability. Moreover, the thin films prepared thereof exhibit smooth and homogeneous morphology with generally high stability over time. 相似文献
57.
在震荡中心哈密顿原理的(oscillation-center Hamiltonian)框架下,讨论了用非对称圆极化的强激光脉冲激发的尾场和在超空泡区中加速正电子的相关问题.研究内容包括:在超强激光所激发的空泡后区中的尾场正电子加速方法和在超空泡区中的雪梨(snow-plow)正电子加速方法.通过理论分析和数值模拟方法定性地比较了2种正电子加速方法的有效加速性能.结果显示,尾场加速的效果比雪梨加速好,2种加速方法中激光脉冲振幅与被加速正电子的能量之间分别存在着指数关系和线性关系.文中还分析了正电子最大尾场和雪梨加速能量与等离子体密度之间的关系 相似文献
58.
Martin Egginger Siegfried Bauer Reinhard Schwödiauer Helmut Neugebauer Niyazi Serdar Sariciftci 《Monatshefte für Chemie / Chemical Monthly》2009,140(7):735-750
Abstract Research into organic field effect transistors (OFETs) has made significant advances—both scientifically and technologically—during
the last decade, and the first products will soon enter the market. Printed electronic circuits using organic resistors, diodes
and transistors may become cheap alternatives to silicon-based systems, especially in large-area applications. A key parameter
for device operation, besides long term stability, is the reproducibility of the current–voltage behavior, which may be affected
by hysteresis phenomena. Hysteresis effects are often observed in organic transistors during sweeps of the gate voltage (V
GS). This hysteresis can originate in various ways, but comparative scientific investigations are rare and a comprehensive picture
of “hysteresis phenomena” in OFETs is still missing. This review provides an overview of the physical effects that cause hysteresis
and discusses the importance of such effects in OFETs in a comparative manner.
Graphical abstract
相似文献
59.
The motion of the shell of charged testparticles falling radially from rest at infinity withzero total angular momentum onto a Kerr–Newmanblack hole is studied. The shell, initially spherical,becomes prolate along the axis of symmetry of the holeduring the fall. The shape of the shell from theviewpoint of distant observers is characterized by meansof the photons moving along geodesics of the outgoing principal null congruence. The motion of theshell is examined analytically for large distances andnear the horizon. In the special case, when at largedistances of the hole the attractive Newtongravitational force is compensated by the repulsive Coulombforce, the complete motion is given explicitly in termsof elementary functions. 相似文献
60.
Jaroslav?StejskalEmail author Miroslava?Trchová Zuzana?Morávková Patrycja?Bober Michal?Bláha Ji?í?Pfleger Przemys?aw?Magdziarz Jan?Proke? Marek?Havlicek Niyazi?Serdar?Sariciftci Andreas?Sperlich Vladimir?Dyakonov Zoran?Zujovic 《Journal of Solid State Electrochemistry》2015,19(9):2653-2664
p-Phenylenediamine was oxidized with p-benzoquinone in the aqueous solutions of methanesulfonic acid (MSA). The conductivity of the products increased with increasing concentration of MSA from 1.5?×?10?12 S cm?1 in 0.1 M MSA up to 3.4?×?10?4 S cm?1 in 5 M MSA. The low-molecular-weight products are basically composed of one p-benzoquinone and two p-phenylenediamine molecules. Their molecular structure is discussed on the basis of mass, Fourier-transform infrared, Raman, NMR and electron paramagnetic resonance (EPR) spectroscopies. The formation of 2,5-di(p-phenylenediamine)-p-benzoquinone protonated with methanesulfonic acid best complies with the information provided by spectroscopic techniques. Its conversion to hydroquinone tautomer explains the formation of unpaired spins observed by EPR and their potential contribution to the conduction. 相似文献