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排序方式: 共有595条查询结果,搜索用时 31 毫秒
1.
Angelika Basch Fiona Beck Thomas Sderstrm Sergey Varlamov Kylie R. Catchpole 《Progress in Photovoltaics: Research and Applications》2012,20(7):837-842
A novel method, snow globe coating, is found to show significant enhancement of the short circuit current JSC (35%) when applied as a scattering back reflector for polycrystalline silicon thin‐film solar cells. The coating is formed from high refractive index titania particles without containing binder and gives close to 100% reflectance for wavelengths above 400 nm. Snow globe coating is a physicochemical coating method executable in pH neutral media. The mild conditions of this process make this method applicable to many different types of solar cells. Copyright © 2012 John Wiley & Sons, Ltd. 相似文献
2.
Fiona M. Blighe Karen Young Juan J. Vilatela Alan H. Windle Ian A. Kinloch Libo Deng Robert J. Young Jonathan N. Coleman 《Advanced functional materials》2011,21(2):364-371
We have measured the mechanical properties of coagulation‐spun polymer–nanotube composite fibers. Both the fiber modulus, Y, and strength, σB, scale linearly with volume fraction, Vf, up to Vf ~10%, after which these properties remain constant. We measured dY/dVf = 254 GPa and dσB/dVf = 2.8 GPa in the linear region. By drawing fibers with Vf < 10% to a draw ratio of ~60%, we can increase these values to dY/dVf = 600 GPa and dσB/dVf = 7 GPa. Raman measurements show the Herman's orientation parameter, S, to increase with drawing, indicating that significant nanotube alignment occurs. Raman spectroscopy also shows that the nanotube effective modulus, YEff, also increases with drawing. We have calculated an empirical relationship between the nanotube orientation efficiency factor, ηo, and S. This allows us to fit the data for YEff versus ηo, showing that the fiber modulus scales linearly with ηo, as predicted theoretically by Krenchel. From the fit, we estimate the nanotube modulus to be; YNT = 480 GPa. Finally, we show that the fiber strength also scales linearly with ηo, giving an effective interfacial stress transfer of τ = 40 MPa and a nanotube critical length of lc=1250 nm. This work demonstrates the validity of the Cox‐Krenchel rule of mixtures and shows that continuum theory still applies at the near‐molecular level. 相似文献
3.
We have studied two kinds of solder reactions between eutectic SnPb and Cu. The first is wetting reaction above the melting
point of the solder, and the second is solid state aging below the melting point of the solder. In wetting reaction, the intermetallic
compound (IMC) formation has a scallop-type morphology. There are channels between the scallops. In solid state aging, the
IMC formation has a layer-type morphology. There are no channels but grain boundaries between the IMC grains. Why scallops
are stable in wetting reactions has been an unanswered question of fundamental interest. We have confirmed that the scallop-type
morphology is stable in wetting reaction by re-wetting the layer-type IMC by molten eutectic SnPb solder. In less than 1 min,
a layer-type Cu6Sn5 is transformed back to scallops by the molten solder at 200 C. In analyzing these reactions, we conclude that the scallop-type
morphology is thermodynamically stable in wetting reaction, but the layer-type morphology is thermodynamically stable in solid
state aging, due to minimization of interfacial and grain boundary energies. 相似文献
4.
A new algorithm is presented which aims to solve problems from compressed sensing - under-determined problems where the solution vector is known a priori to be sparse. Upper bounds on the solution vector are found so that the problem can be reformulated as a box-constrained quadratic programme. A sparse solution is sought using a Barzilai-Borwein type projection algorithm. New insight into the choice of step length is provided through a study of the special structure of the underlying problem together with upper bounds on the step length. Numerical experiments are conducted and results given, comparing this algorithm with a number of other current algorithms. 相似文献
5.
Fiona H. Scholes Tino Ehlig Michael James Kwan H. Lee Noel Duffy Andrew D. Scully T. Birenda Singh Kevin N. Winzenberg Pete Kemppinen Scott E. Watkins 《Advanced functional materials》2013,23(45):5655-5662
A comprehensive study of the effect of intraphase microstructure on organic photovoltaic (OPV) device performance is undertaken. Utilizing a bilayer device architecture, a small molecule donor (TIPS‐DBC) is deposited by both spin‐coating and by thermal evaporation in vacuum. The devices are then completed by thermal evaporation of C60, an exciton blocking layer and the cathode. This bilayer approach enables a direct comparison of device performance for donor layers in which the same material exhibits subtle differences in microstructure. The electrical performance is shown to differ considerably for the two devices. The bulk and interfacial properties of the donor layers are compared by examination with photoelectron spectroscopy in air (PESA), optical absorption spectroscopy, charge extraction of photo‐generated charge carriers by linearly increasing voltage (photo‐CELIV), time‐resolved photoluminescence measurements, X‐ray reflectometry (XR), and analysis of dark current behavior. The observed differences in device performance are shown to be influenced by changes to energy levels and charge transport properties resulting from differences in the microstructure of the donor layers. Importantly, this work demonstrates that in addition to the donor/acceptor microstructure, the intraphase microstructure can influence critical parameters and can therefore have a significant impact on OPV performance. 相似文献
6.
Smy T. Tan L. Chan K. Tait R.N. Broughton J.N. Dew S.K. Brett M.J. 《Electron Devices, IEEE Transactions on》1998,45(7):1414-1425
Modified sputtering techniques, such as long throw sputtering, collimation, and ionized sputtering, have been proposed to improve VLSI topography bottom coverage by narrowing the angular distribution of the sputter flux at the substrate and reducing subsequent flux shadowing at the bottom of topography. This paper first investigates a number of unique aspects involved in the simulation of long throw sputter systems. In particular, time importance of inhomogeneous film density and nonunity sticking coefficients are addressed. The second part of the paper presents a simulation study of long throw sputtering, providing a comparison to collimated and standard sputtering systems. The simulations are performed using the SIMSPUD/SIMBAD ballistic deposition tool. SIMSPUD is used to study film uniformity over a 300-mm wafer and to generate angular distributions at the center and edge of the wafer. The ability of SIMBAD to simulate directed sputtering systems is verified by direct comparison to Ti films deposited into oxide trenches. The importance of modeling the film microstructure is demonstrated by comparison between cross-sectional SEM's micrograph for evaporation and modeling results, such as long throw sputtering with a variety of substrate/target spacings, typical “standard” as well as “collimated” systems. SEM's of overhang structures and simulations are also presented to demonstrate nonunity sticking during the co-sputtering of TiW 相似文献
7.
Simonetta Pazzaglia Barbara Tanno Ilaria De Stefano Paola Giardullo Simona Leonardi Caterina Merla Gabriele Babini Seda Tuncay Cagatay Ammar Mayah Munira Kadhim Fiona M. Lyng Christine von Toerne Zohaib N. Khan Prabal Subedi Soile Tapio Anna Saran Mariateresa Mancuso 《International journal of molecular sciences》2022,23(4)
Cell communication via exosomes is capable of influencing cell fate in stress situations such as exposure to ionizing radiation. In vitro and in vivo studies have shown that exosomes might play a role in out-of-target radiation effects by carrying molecular signaling mediators of radiation damage, as well as opposite protective functions resulting in resistance to radiotherapy. However, a global understanding of exosomes and their radiation-induced regulation, especially within the context of an intact mammalian organism, has been lacking. In this in vivo study, we demonstrate that, compared to sham-irradiated (SI) mice, a distinct pattern of proteins and miRNAs is found packaged into circulating plasma exosomes after whole-body and partial-body irradiation (WBI and PBI) with 2 Gy X-rays. A high number of deregulated proteins (59% of WBI and 67% of PBI) was found in the exosomes of irradiated mice. In total, 57 and 13 miRNAs were deregulated in WBI and PBI groups, respectively, suggesting that the miRNA cargo is influenced by the tissue volume exposed to radiation. In addition, five miRNAs (miR-99b-3p, miR-200a-3p, miR-200a, miR-182-5p, miR-182) were commonly overexpressed in the exosomes from the WBI and PBI groups. In this study, particular emphasis was also given to the determination of the in vivo effect of exosome transfer by intracranial injection in the highly radiosensitive neonatal cerebellum at postnatal day 3. In accordance with a major overall anti-apoptotic function of the commonly deregulated miRNAs, here, we report that exosomes from the plasma of irradiated mice, especially in the case of WBI, prevent radiation-induced apoptosis, thus holding promise for exosome-based future therapeutic applications against radiation injury. 相似文献
8.
Oscar O. Solis-Castro Marcelo N. Rivolta Fiona M. Boissonade 《International journal of molecular sciences》2022,23(5)
Evidence from dental-related stem cells (DRSCs) suggests an enhanced potential for ectodermal lineage differentiation due to their neural crest origin. Growing evidence that DRSC cultures can produce cells with a neural crest-derived stem cell (NCSC)-like phenotype supports their potential for future therapeutic approaches for neurodegenerative diseases and nerve injuries. However, most of the evidence is limited to the characterization of DRSCs as NCSCs by detecting the expression of neural crest markers. Only a few studies have provided proof of concept of an improved neuro-glial differentiation or direct applicability in relevant models. In addition, a current problem is that several of the existing protocols do not meet manufacturing standards for transferability to a clinical scenario. This review describes the current protocols to obtain NCSCs from DRSCs and their characterization. Also, it provides important considerations from previous work where DRSCs were established and characterized as mesenchymal stromal cells but studied for their neuro-glial differentiation potential. The therapeutic advancement of DRSCs would depend on establishing protocols that can yield a neural crest-like phenotype efficiently, using appropriate manufacturing standards and testing them in relevant models of disease or injury. Achieving these conditions could then facilitate and validate the therapeutic potential of DRSC-NCSCs in regenerative therapies. 相似文献
9.
10.
We have prepared high surface area, conductive, mechanically robust, responsive polyaniline–carbon nanotube composite films. These were produced by filtration from dilute dispersions of polyaniline nanofibers and single-walled carbon nanotubes. Unlike polyaniline alone, these composites are mechanically stable, maintain large intractable surfaces and exhibit greatly enhanced response/recovery behavior to changes in their local environment. This is illustrated by exposing the films to ammonia. 相似文献