排序方式: 共有11条查询结果,搜索用时 15 毫秒
1.
A new high: Cannabis as a budding source of carbon-based materials for electrochemical power sources
Zahra I. Rana Ami R. Shah Alice V. Llewellyn Katrina Mazloomian Patricia McAlernon Thomas S. Miller Patrick L. Cullen Paul R. Shearing Dan J.L. Brett 《Current Opinion in Electrochemistry》2022
Cannabis sativa L., a low-cost, fast-growing herbaceous plant, is seeing a resurgence in widespread cultivation as a result of new policies and product drive. Its biodegradable and environmentally benign nature coupled with its high specific surface area and three-dimensional hierarchal structure makes it an excellent candidate for use as a biomass-derived carbon material for electrochemical power sources. It is proposed that this ‘wonder crop’ could have an important role in the energy transition by providing high-functioning carbon-based materials for electrochemistry. In this article, all instances of C. sativa usage in batteries, fuel cells and supercapacitors are discussed with a focus on highlighting the high capacity, rate capability, capacitance, current density and half-wave potential that can be achieved with its utilisation in the field. 相似文献
2.
Although many complex real-world networks are weighted, unweighted networks are used in many applications such as sensor networks. In this Letter it is shown using properly weighted networks the performance can be greatly enhanced by reducing the time necessary for the average consensus. Random geographical models are adapted as network models and a method based on mutually coupled phase oscillators is used for providing average consensus over the network. The consensus time is calculated by numerically solving the network's differential equations and monitoring the average error. The simulation results on some sample networks show that the consensus time is dramatically reduced when the proposed weights are used for the links of the underlying network. 相似文献
3.
A Amirsadeghi JJ Lee S Park 《Langmuir : the ACS journal of surfaces and colloids》2012,28(31):11546-11554
The chemistry and composition of UV-sensitive resists are key factors determining the stress in the molded resist structure in UV nanoimprint lithography (UV-NIL) and thus the success of the process. The stress in the molded structure is mainly generated due to shrinkage of the resist in the UV curing step and also adhesion and friction at the stamp/resist interface in the subsequent demolding step. Thus, understanding of the stress generated in these steps is critical to the improvement of the process as well as the development of new UV resists. In this paper the effect of resist composition on the stress generation was studied by numerical simulations of the curing and demolding steps in UV-NIL. Parameters required for the simulation, such as resist shrinkage, Young's modulus, fracture strength, friction coefficient, crack initiation stress, and debonding energy, were determined experimentally for different resist compositions. As the cross-linking agent concentration increases the fracture strength also improves. In addition, as more cross-linking agent is added to the resist composition, both shrinkage stress due to the curing and also adhesion at the stamp/resist interface increase resulting in a larger maximum local stress experienced by the resist on demolding. By normalizing the overall maximum local stress by the fracture stress of the resist, we found that there is an optimum for the cross-linking agent concentration that leads to the most successful imprinting. Our finding is also corroborated by qualitative experimentations performed for UV-NIL with various resist compositions. 相似文献
4.
Gholam Hossein Mahdavinia Mohammad R. Mohammadizadeh Noushin Ariapour Maryam Alborz 《Tetrahedron letters》2014
A one-pot, efficient and chemoselective procedure for the synthesis of new 3H-spiro[isobenzofuran-1,2′-pyrrole]-3,3′(1′H)-dione derivatives has been developed which involves room temperature oxidative cleavage of 3a,8b-dihydroxyindeno[1,2-b]pyrroles themselves synthesized from the reaction of ninhydrin and enaminones in 30% ethanol. A reasonable mechanism is proposed for the oxidation reaction based on the results of this study and our previous related work. 相似文献
5.
Two phase mixture model is used to numerically simulate the turbulent forced convection of Al2O3-Water nanofluid in a channel with corrugated wall under constant heat flux. Both mixture and single phase models are implemented to study the nanofluid flow in such a geometry and the results have been compared. The effects of the volume fraction of nanoparticles, Reynolds number and amplitude of the wavy wall on the rate of heat transfer are investigated. The results showed that with increasing the volume fraction of nanoparticles, Reynolds number and amplitude of wall waves, the rate of heat transfer increases. Also the results showed that the mixture model yields to higher Nusselt numbers than the single phase model in a similar case. 相似文献
6.
Sunggook Park Zhichao Song Lance Brumfield Alborz Amirsadeghi Jaejong Lee 《Applied Physics A: Materials Science & Processing》2009,97(2):395-402
In thermal nanoimprint lithography, temperature is one of the most important process parameters. Temperature is not only important
for the flow of resist during molding but also for demolding, the process by which the imprint stamp is removed from the molded
resist/substrate. This is because thermal stress and friction and adhesion forces generated at the stamp/resist interface
and the mechanical strength of the resist are all dependent on temperature. In this paper, we demonstrate via both experimentation
and numerical simulation that an optimal temperature (T
d) leading to minimal deformation of molded resist exists for demolding. The ease of demolding was directly accessed by measuring
demolding force at different T
d for a Si stamp/PMMA/Si substrate system of 4-in.-diameter using a mechanical tester. Numerically, the demolding process for
a simple two-dimensional model of a Si stamp/poly(methyl methacrylate) (PMMA) resist/Si substrate system was simulated using
a finite-element method for different T
d, assuming viscoelasticity of the PMMA resist and temperature dependence of friction coefficients at the stamp/PMMA interface.
We found that a temperature leading to the minimum in both the demolding force and the normalized stress vs. T
d curves exists below the glass transition temperature of the PMMA resist, from which the optimal T
d was derived. 相似文献
7.
Development of all polymer-based nanofluidic devices using replication technologies, which is a prerequisite for providing devices for a larger user base, is hampered by undesired substrate deformation associated with the replication of multi-scale structures. Therefore, most nanofluidic devices have been fabricated in glass-like substrates or in a polymer resist layer coated on a substrate. This letter presents a rapid, high fidelity direct imprinting process to build polymer nanofluidic devices in a single step. Undesired substrate deformation during imprinting was significantly reduced through the use of a polymer stamp made from a UV-curable resin. The integrity of the enclosed all polymer-based nanofluidic system was verified by a fluorescein filling experiment and translocation/stretching of λ-DNA molecules through the nanochannels. It was also found that the funnel-like design of the nanochannel inlet significantly improved the entrance of DNA molecules into nanochannels compared to an abrupt nanochannel/microfluidic network interface. 相似文献
8.
Szychowski J Mahdavi A Hodas JJ Bagert JD Ngo JT Landgraf P Dieterich DC Schuman EM Tirrell DA 《Journal of the American Chemical Society》2010,132(51):18351-18360
The azide-alkyne cycloaddition provides a powerful tool for bio-orthogonal labeling of proteins, nucleic acids, glycans, and lipids. In some labeling experiments, e.g., in proteomic studies involving affinity purification and mass spectrometry, it is convenient to use cleavable probes that allow release of labeled biomolecules under mild conditions. Five cleavable biotin probes are described for use in labeling of proteins and other biomolecules via azide-alkyne cycloaddition. Subsequent to conjugation with metabolically labeled protein, these probes are subject to cleavage with either 50 mM Na(2)S(2)O(4), 2% HOCH(2)CH(2)SH, 10% HCO(2)H, 95% CF(3)CO(2)H, or irradiation at 365 nm. Most strikingly, a probe constructed around a dialkoxydiphenylsilane (DADPS) linker was found to be cleaved efficiently when treated with 10% HCO(2)H for 0.5 h. A model green fluorescent protein was used to demonstrate that the DADPS probe undergoes highly selective conjugation and leaves a small (143 Da) mass tag on the labeled protein after cleavage. These features make the DADPS probe especially attractive for use in biomolecular labeling and proteomic studies. 相似文献
9.
10.
Controlling size, shape and homogeneity of embryoid bodies using poly(ethylene glycol) microwells 总被引:1,自引:0,他引:1
Karp JM Yeh J Eng G Fukuda J Blumling J Suh KY Cheng J Mahdavi A Borenstein J Langer R Khademhosseini A 《Lab on a chip》2007,7(6):786-794
Directed differentiation of embryonic stem (ES) cells is useful for creating models of human disease and could potentially generate a wide array of functional cell types for therapeutic applications. Methods to differentiate ES cells often involve the formation of cell aggregates called embryoid bodies (EBs), which recapitulate early stages of embryonic development. EBs are typically made from suspension cultures, resulting in heterogeneous structures with a wide range of sizes and shapes, which may influence differentiation. Here, we use microfabricated cell-repellant poly(ethylene glycol) (PEG) wells as templates to initiate the formation of homogenous EBs. ES cell aggregates were formed with controlled sizes and shapes defined by the geometry of the microwells. EBs generated in this manner remained viable and maintained their size and shape within the microwells relative to their suspension counterparts. Intact EBs could be easily retrieved from the microwells with high viability (>95%). These results suggest that the microwell technique could be a useful approach for in vitro studies involving ES cells and, more specifically, for initiating the differentiation of EBs of greater uniformity based on controlled microenvironments. 相似文献