6,915 research outputs found
Langmuir and LB properties of two calix[4]resorcinarenes: Interactions with various analytes
No full textThe ability of calixarene-based molecules to interact with amino acids has been
the basis of many studies. The Langmuir and LB properties of two calix
[4]resorcinarenes have been investigated. The properties of the layer formed at
the air–water interface were studied by surface pressure–area isotherms. LB
deposition onto glass substrates has shown that multilayer assemblies can be
built up. The UV–vis spectra of resulting LB films have been recorded,
indicating that the compounds are coloured as a result of intra-molecular charge
transfer bands. The sensitivity of the surface pressure–area isotherms has been
investigated in relation to the exposure to various analytes delivered from the
subphase (i.e. amino acids). Furthermore, exposure of the LB films to a wide
range of vapours (e.g. amines, alcohols, thiols) has led to modified UV–v
EFFECT OF CHEMICAL-POTENTIAL SHIFT ON THERMODYNAMICAL PROPERTIES OF THE MIXED-VALENCE COMPOUNDS
No full textStarting from the SU(N(d)) Anderson lattice model in the slave boson formalism, we study the effect of the chemical potential shift on the thermodynamic properties of the mixed valence lattice system by using the Green's function technique. In the mean field approximation, the self-consistent equations of the mean field parameters and the chemical potential are obtained. The average number of f electrons, the magnetic susceptibility and the specific heat are calculated. The numerical studies show that the shift of the chemical potential has a strong effect on the thermodynamic properties.Physics, MultidisciplinarySCI(E)中国科学引文数据库(CSCD)1ARTICLE2147-1542
Light-Weight Free-Standing Carbon Nanotube-Silicon Films for Anodes of Lithium Ion Batteries
No full textSilicon is an attractive alloy-type anode material because of its highest known capacity (4200 mAh/g). However, lithium insertion into and extraction from silicon are accompanied by a huge volume change, up to 300%, which induces a strong strain on silicon and causes pulverization and rapid capacity fading due to the loss of the electrical contact between part of silicon and current collector. Si nanostructures such as nanowires, which are chemically and electrically bonded to the current collector, can overcome the pulverization problem, however, the heavy metal current collectors in these systems are larger in weight than Si active material. Herein we report a novel anode structure free of heavy metal current collectors by integrating a flexible, conductive carbon nanotube (CNT) network into a Si anode. The composite film is free-standing and has a structure similar to the steel bar reinforced concrete, where the infiltrated CNT network functions as both mechanical support and electrical conductor and Si as a high capacity anode material for Li-ion battery. Such free-standing film has a low sheet resistance of similar to 30 Ohm/sq. It shows a high specific charge storage capacity (similar to 2000 mAh/g) and a good cycling life, superior to pure sputtered-on silicon films with similar thicknesses. Scanning electron micrographs show that Si is still connected by the CNT network even when small breaking or cracks appear in the film after cycling. The film can also "ripple up" to release the strain of a large volume change during lithium intercalation. The conductive composite film can function as both anode active material and current collector. It offers similar to 10 times improvement in specific capacity compared with widely used graphite/copper anode sheets.Y
Photoelectro-chemical properties of anilino squaraine derivatives in LB films
No full textPhotocurrent generation from Langmuir-Blodgett (LB) overlays on indium tin oxide (ITO) electrodes, where the active components are 2,4-bis[4-(dibutylamino)-2-hydroxyphenyl]squaraine (1) and the unsubstituted analogue, 2,4-bis[4-(dibutylamino)phenyl]squaraine (2), have been investigated. Dye 1 shows improved behaviour compared with the latter and differences in performance are attributed to a modified aggregate structure, this being indicated by variations in the LB film spectra. The photocurrent generation is enhanced by the presence of electron accepters, e.g. N,N'-dimethyl-4,4'-bipyridinium diiodide (MV2+), but quenched by electron donors, e.g. hydroquinone (HQ). The concentration dependence is reported
Comments on author citations for nomenclatural novelties published in volume 15 of the Flora Reipublicae Popularis Sinicae (FRPS)
No full textMetal current collector-free freestanding silicon-carbon 1D nanocomposites for ultralight anodes in lithium ion batteries
No full textAlthough current collectors take up more weight than active materials in most lithium ion battery cells, so far research has been focused mainly on improving gravimetric capacities of active materials. To address this issue of improving gravimetric capacities based on overall cell components, we develop freestanding nanocomposites made of carbon nanofibers (CNFs) and silicon nanowires (SiNWs) as metal current collector-free anode platforms. Intrinsically large capacities of SiNWs as active materials in conjunction with the light nature of freestanding CNF films allow the nanocomposites to achieve 3-5 times improved gravimetric capacities compared to what have been reported in the literature. Moreover, three-dimensional porous structures in the CNF films facilitate increased mass loadings of SiNWs when compared to flat substrates and result in good cycle lives over 40 cycles. This type of nanocomposite cell suggests that 3D porous platforms consisting of light nanomaterials can provide for higher gravimetric and areal capacities when compared to conventional battery cells based on flat, heavy metal substrates. (c) 2010 Elsevier B.V. All rights reserved
EFFECTS OF THE FLUCTUATIONS ON THERMODYNAMIC PROPERTIES OF THE MIXED-VALENCE COMPOUNDS
No full textBased on the SU(N-d) Anderson lattice model in the slave boson formalism, we study the effect of fluctuations around the saddle-point approximation on the thermodynamic properties for mixed valence lattice systems. The fluctuation component of slave boson held is explicitly introduced and its interactions with electrons are studied. By using the Green's function technique we obtain modified self-consistent equations of mean-field parameters and free energy. The fluctuation correction to the pseudophase transition temperature is obtained, and the validity of the mean-field approximation is examined. In the limit of low energy and small momentum transfer, a fluctuation correction to the specific heat proportional to T(3)lnT at low temperature is extracted. The chemical potential shift is also studied. In order to describe the thermodynamic properties correctly, it is important to determine the chemical potential shift properly.Physics, MultidisciplinarySCI(E)0ARTICLE3277-2902
HEAVY-FERMION SEMICONDUCTOR BEHAVIOR OF THE SU(N-D) ANDERSON LATTICE MODEL
No full textThe heavy-fermion semiconductor behavior of the SU(N-d) Anderson lattice model is examined by using the slave-boson technique within the framework of mean-field theory. The results show that the slave-boson mean-field theory of this model can present a heavy Fermi liquid or a heavy-fermion semiconductor ground state for different n values (n is the total number of the conduction and the on-site f electrons per lattice site), thus providing a unified description of the heavy Fermi liquid and the heavy-fermion semiconductor. The basic features of this theory are in qualitative agreement with the experimentally observed heavy-fermion semiconductor behavior of some rare-earth compounds.Physics, Condensed MatterSCI(E)2ARTICLE85611-56165
Learning theories and interprofessional education: a user's guide
No full textThere is increasing interest in the theoretical underpinning of interprofessional education (IPE) and writers in this field are drawing on a wide range of disciplines for theories that have utility in IPE. While this has undoubtedly enriched the research literature, for the educational practitioner, whose aim is to develop and deliver an IPE curriculum that has sound theoretical underpinnings, this plethora of theories has become a confusing, and un-navigable quagmire. This article aims to provide a compass for those educational practitioners by presenting a framework that summarizes key learning theories used in IPE and the relationship between them. The study reviews key contemporary learning theories from the wider field of education used in IPE and the explicit applications of these theories in the IPE literature to either curriculum design or programme evaluation. Through presenting a broad overview and summary framework, the study clarifies the way in which learning theories can aid IPE curriculum development and evaluation. It also highlights areas where future theoretical development in the IPE field is required
The Human Penguin Project: Climate, social integration, and core body temperature
No full textFull author list: IJzerman, H.; Lindenberg, S.; Dalgar, I.; Weissgerber, S.S.C.; Vergara, R.C.; Cairo, A.H.; Colic, M.V.; Dursun, P.; Frankowska, N.; Hadi, R.; Hall, C.J.; Hong, Y.; Hu, C.P.; Joy-Gaba, J.;, Lazarevic D, Lazarevic LB, Parzuchowski M, Ratner KG, Rothman D, Sim S, Simao C, Song M, Stojilovic D, Blomster JK, Brito R, Hennecke M, Jaume-Guazzini F, Schubert TW, Schutz A, Seibt B, Zickfeld JH</p
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