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排序方式: 共有232条查询结果,搜索用时 31 毫秒
111.
Mahabub A. Bhuiyan Zakhar R. Kudrynskyi Debarati Mazumder Jake D. G. Greener Oleg Makarovsky Christopher J. Mellor Evgeny E. Vdovin Benjamin A. Piot Inna I. Lobanova Zakhar D. Kovalyuk Marina Nazarova Artem Mishchenko Kostya S. Novoselov Yang Cao Laurence Eaves Go Yusa Amalia Patan 《Advanced functional materials》2019,29(3)
The transfer of electronic charge across the interface of two van der Waals crystals can underpin the operation of a new class of functional devices. Among van der Waals semiconductors, an exciting and rapidly growing development involves the “post‐transition” metal chalcogenide InSe. Here, field effect phototransistors are reported where single layer graphene is capped with n‐type InSe. These device structures combine the photosensitivity of InSe with the unique electrical properties of graphene. It is shown that the light‐induced transfer of charge between InSe and graphene offers an effective method to increase or decrease the carrier density in graphene, causing a change in its resistance that is gate‐controllable and only weakly dependent on temperature. The charge transfer at the InSe/graphene interface is probed by Hall effect and photoconductivity measurmentes and it is demonstrated that light can induce a sign reversal of the quantum Hall voltage and photovoltaic effects in the graphene layer. These findings demonstrate the potential of light‐induced charge transfer in gate‐tunable InSe/graphene phototransistors for optoelectronics and quantum metrology. 相似文献
112.
Cristina Martín Amalia Ruiz Sandeep Keshavan Giacomo Reina Diane Murera Yuta Nishina Bengt Fadeel Alberto Bianco 《Advanced functional materials》2019,29(39)
The design of multifunctional materials able to both selectively deliver a drug into cells in a targeted manner and display an enhanced propensity for biodegradation is an important goal. Here, graphene oxide (GO) is functionalized with the chemotactic peptide N‐formyl‐methionyl‐leucyl‐phenylalanine (fMLP) known to interact with the formyl peptide receptor, which is expressed in different cancer cells, including cervical carcinoma cells. This study highlights the ability of GOfMLP for targeted drug delivery and cancer cell killing and the subsequent degradation capacity of the hybrid. Biodegradation is assessed via Raman spectroscopy and transmission electron microscopy. The results show that GOfMLP is susceptible to faster myeloperoxidase‐mediated degradation. The hybrid material, but not GO, is capable of inducing neutrophil degranulation with subsequent degradation, being the first study showing inducible neutrophil degradation by the nanomaterial itself with no prior activation of the cells. In addition, confocal imaging and flow cytometry using HeLa cells demonstrate that GOfMLP is able to deliver the chemotherapeutic agent doxorubicin faster into cells, inducing higher levels of apoptosis, when compared to nonfunctionalized GO. The results reveal that GOfMLP is a promising carrier able to efficiently deliver anticancer drugs, being endowed with the ability to induce its own biodegradation. 相似文献
113.
Time‐Dependent Free‐Particle Salpeter Equation: Numerical and Asymptotic Analysis in the Light of the Fundamental Solution
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A detailed study of the spinless (1+1)D free‐particle Salpeter equation is presented. It involves several aspects of the topic: from the analysis of the behavior of solutions of the equation, both numerically evaluated and asymptotically approximated for definite initial conditions, to the comparison with the behavior of the corresponding solutions of the Schrödinger equation in order to both highlight the differences and to possibly understand how the latter “flow” in the former. Interesting analogies with other fields of physics, in particular with optics, are suggested. 相似文献
114.
115.
Patan Yousaf Khan 《哲学杂志》2013,93(18):2031-2045
The present investigation is aimed at understanding the effect of a matrix on the phase transformation of biphasic embedded Pb–Sn alloy nanoparticles. The melting and solidification behaviours of eutectic (Pb26.1Sn73.9) nanoparticles embedded in icosahedral (IQC) as well as decagonal quasicrystalline (DQC) matrix have been studied. Electron microscopic observations reveal that the major portion of the alloy nanoparticle consists of body-centred tetragonal β-(Sn) with face-centred cubic (Pb) constituting the cap. (Pb) bears specific orientation relationships (OR) with the surrounding IQC matrix, whereas β-(Sn) does not have any specific OR. For alloy particles embedded in the DQC matrix, both (Pb) and β-(Sn) bear specific OR. In case of IQC matrix, differential scanning calorimetric measurements reveal sharp melting but diffuse solidification peaks for the embedded nanoparticles. On the other hand, sharp melting and solidification peaks are observed for the nanoparticles embedded in the DQC matrix. The IQC and DQC are heat-treated at different temperatures to observe the effect of the matrix on the phase transformation of the alloy nanoparticles. The formation of well- developed facets in the nano-particles and defects in the matrix have been found to play a crucial role in determining the phase transformation of the alloy nanoparticles in the heat-treated samples. The experimental observations are rationalized using available literature. 相似文献
116.
117.
Marcelino Anguiano-Morales Amalia Martínez Sabino Chávez-Cerda 《Optics Communications》2008,281(3):401-407
A combination of an axicon and an amplitude mask is used to obtain an intensity distribution that differs from the typical Bessel one. Experimental and numerical characterization of the field is made for different propagation distances and types of amplitude masks. 相似文献
118.
R Domínguez A Rodríguez A Maestre I Robina ML Moyá 《Journal of colloid and interface science》2012,386(1):228-239
In this work, three didodecyl dicationic dibromide dimeric surfactants 12-s-12,2Br(-), with different methylene spacer lengths (s=7, 9, and 11) were prepared and characterized and their properties compared to those of 12-s-12,2Br(-) surfactants with s=2, 3, 4, 5, 6, 8, 10, and 12. Information about the critical micelle concentration, the micellar ionization degree, the average aggregation number and the polarity of the interfacial region, and microviscosity of the micellar interior was obtained by using different techniques. Their surface activity was investigated by means of surface tension measurements. Micellization was also studied by using (1)H NMR and diffusion NMR (DOSY) spectroscopy as well as isothermal titration calorimetry. The values of the thermodynamic parameters show that the dimeric surfactants micellization is exothermic and driven by entropy. The occurrence of morphological transitions upon increasing surfactant concentration was studied, and the results indicate that the spacer length, s, plays a key role in the micellar growth of 12-s-12,2Br(-) aggregates. The value of s not only control the magnitude of C(*), the surfactant concentration above which the morphological transition from spherical micelles into elongated ones occurs, but also the sign of the enthalpy change accompanying the sphere-to-rod transition. 相似文献
119.
Martín VI Rodríguez A del Mar Graciani M Moyá ML 《Journal of colloid and interface science》2012,368(1):326-335
The micellization and micellar growth in the mixtures of N,N-dimethyl, N-phenyl,N-dodecylammonium bromide, PH12, N,N-dimethyl,N-ciclohexylmethyl,N-dodecylammonium bromide, CH12, and their two dimeric counterparts m-dimethylphenyl-α-ω-bis(dodecyldimethylammonium) bromide, 12PH12, and m-dimethylciclohexyl-α-ω-bis(dodecyldimethylammonium) bromide, 12CH12, with dodecyltrimethylammoniumbromide, DTAB, and with N-decanoyl N-methylglucamide, MEGA10, were investigated at 303 K. Circular dichroism, CD, experiments showed the formation of mixed micelles. Two-dimensional, 2D, rotating frame nuclear Overhauser effect spectroscopy (ROESY) experiments indicated that the arrangement of the rings in the pure and mixed micelles is similar, with the rings bent into the micelle interior avoiding contact with water. Application of different theoretical approaches shows that PH12 and CH12 mixtures with DTAB and with MEGA10 behave almost ideally. The binary systems of 12PH12 and 12CH12 with DTAB and with MEGA10 show a non-ideal behavior. An increment in the solution mole fraction of MEGA10 and DTAB diminishes the tendency of the micellar aggregates to grow. 相似文献
120.
Miguel ángel García-Sevillano Macarena González-Fernández Rocío Jara-Biedma Tamara García-Barrera Amalia Vioque-Fernández Juan López-Barea Carmen Pueyo José Luis Gómez-Ariza 《Chemical Papers》2012,66(10):914-924
A speciation approach based on orthogonal chromatographic systems coupled to inductively coupled plasma mass spectrometry (ICP-MS) was used to characterise the biological response of free-living mice Mus spretus to environmental pollution caused by arsenic in different areas of the Do?ana National Park (south-west Spain). The relative presence of inorganic and organic forms of arsenic was studied in cytosolic extracts from high metabolic activity organs of Mus spretus mice: kidneys, liver, and brain. An instrumental coupling of size-exclusion chromatography with UV and collision/reaction cell-ICP-MS detectors (SEC-UV-ICP-ORC-MS) both in analytical and preparative scale was used for this purpose. The results showed the presence of low molecular mass (LMM) molecules linked to arsenic in these tissues especially in the kidneys, where the presence of these arsenic metabolites was higher. On the other hand, the presence of these arsenicals varied from one area to the other, which can be related to a different occurrence of contaminants. These low molecular mass fractions were collected by preparative SEC chromatography for later study with ion exchange chromatography and detection by ICP-ORC-MS, using both anionic and cationic columns. The results showed the higher presence of MMA and DMA in kidneys of mice caught in contaminated areas and the existence of small amounts of unidentified arsenicals when cation-exchange chromatography was used, which could be related to the presence of dimethylarsinoylethanol (DMAE), thioarsenic species, or arsenocholine (AsC). 相似文献