| 1. |
- Chen, X, et al.
(author)
-
Bismuth Effects on Electronic Levels in GaSb(Bi)/AlGaSb Quantum Wells Probed by Infrared Photoreflectance
- 2015
-
In: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 32:6
-
Journal article (peer-reviewed)abstract
- GaSb(Bi)/Al0.2Ga0.8Sb single quantum wells are characterized by a Fourier transform infrared spectrometerbased photoreflectance method at 77 K. Spatially direct and indirect transitions between the electronic levels at and above the effective band gap are well resolved. The shifts of the electronic levels with Bi incorporation are identified quantitatively. The results show that the upshift of the valence band edge is clarified to be dominant, while the Bi-induced downshift of the conduction band edge does exist and contributes to the band gap reduction in the GaSbBi quantum-well layer by (29±6)%.
|
|
| 2. |
- Liu, Y., et al.
(author)
-
Bandwidth scaling of phase-modulated CW comb through four-wave mixing on silicon nano-waveguide
- 2013
-
In: 2013 Conference on Lasers and Electro-Optics, CLEO 2013; San Jose, CA; United States; 9 June 2013 through 14 June 2013. - 9781557529725 ; , s. Art. no. 6833039-
-
Conference paper (peer-reviewed)abstract
- We demonstrate a scheme to scale the bandwidth of a frequency comb generated by phase modulation of CW lasers using four-wave mixing in a silicon nano-waveguides, resulting in >100 comb lines spaced by 10-GHz within 5-dB bandwidth.
|
|
| 3. |
- Tang, K., et al.
(author)
-
Achieving superior cryogenic tensile properties in a Ti-doped (Fe40Mn40Co10Cr10)(96.7)C-3.3 high-entropy alloy by recovering deformation twinning
- 2021
-
In: Materials Science & Engineering. - : Elsevier BV. - 0921-5093 .- 1873-4936. ; 808
-
Journal article (peer-reviewed)abstract
- A minor Ti-doped (Fe40Mn40Co10Cr10)(96.7)C-3.3 high-entropy alloy presents a higher yield strength and a littler lower elongation than the un-doped one at room temperature. And more interestingly, superior cryogenic temperature (77 K) tensile properties: yield strength of similar to 1 GPa, ultimate tensile strength of similar to 1.5 GPa, and elongation of similar to 52% are achieved in this alloy. The high yield strength is attributed to the improved strengthening effect by the grain boundary and nano-sized TiC precipitation and the better ductility at cryogenic temperature is ascribed to the recovery of deformation twinning by titanium addition. It is proposed that the critical twinning stress of C-contained alloy is temperature dependent, which is related with the unbalanced pinning effect assisted twinning mechanism due to carbon diffusion.
|
|
| 4. |
- Vassilaras, S., et al.
(author)
-
The Algorithmic Aspects of Network Slicing
- 2017
-
In: IEEE Communications Magazine. - : Institute of Electrical and Electronics Engineers (IEEE). - 0163-6804 .- 1558-1896. ; 55:8, s. 112-119
-
Journal article (peer-reviewed)abstract
- Network slicing is a technique for flexible resource provisioning in future wireless networks. With the powerful SDN and NFV technologies available, network slices can be quickly deployed and centrally managed, leading to simplified management, better resource utilization, and cost efficiency by commoditization of resources. Departing from the one-Type-fits-All design philosophy, future wireless networks will employ the network slicing methodology in order to accommodate applications with widely diverse requirements over the same physical network. On the other hand, deciding how to efficiently allocate, manage, and control the slice resources in real time is very challenging. This article focuses on the algorithmic challenges that emerge in efficient network slicing, necessitating novel techniques from the communities of operation research, networking, and computer science.
|
|
| 5. |
- Hansson, Josef, 1991, et al.
(author)
-
Bipolar electrochemical capacitors using double-sided carbon nanotubes on graphite electrodes
- 2020
-
In: Journal of Power Sources. - : Elsevier BV. - 0378-7753. ; 451
-
Journal article (peer-reviewed)abstract
- The electrochemical capacitor (EC) is a key enabler for the miniaturized self-powered systems expected to become ubiquitous with the advent of the internet-of-things (IoT). Vertically aligned carbon nanotubes (VACNTs) on graphite holds promise as electrodes for compact and low-loss ECs. However, as with all ECs, the operating voltage is low, and miniaturization of higher voltage devices necessitates a bipolar design. In this paper, we demonstrate a bipolar EC using graphite/VACNTs electrodes fabricated using a joule heating chemical vapor deposition (CVD) setup. The constructed EC contains one layer of double-sided VACNTs on graphite as bipolar electrode. Compared to a series connection of two individual devices, the bipolar EC has 22% boost in volumetric energy density. More significant boost is envisaged for stacking more bipolar electrode layers. The energy enhancement is achieved without aggravating self-discharge (71.2% retention after 1 h), and at no sacrifice of cycling stability (96.7% over 50000 cycles) owing to uniform growth of VACNTs and thus eliminating cell imbalance problems.
|
|
| 6. |
- Zhang, L, et al.
(author)
-
Effects of molecular weight of nitrocellulose on structure and properties of polyurethane nitrocellulose IPNs
- 1999
-
In: Journal of Polymer Science Part B-Polymer Physics. ; 37:14, s. 1623-1631
-
Journal article (peer-reviewed)abstract
- Semi-interpenetrating polymer network (semi-IPN) coatings were prepared by using castor oil-based polyurethane (PU) and nitrocellulose (NC) with various viscosity-average molecular weights (Mη) from 6 × 104 to 42 × 104, and coated on a regenerated cellulose (RC) film to obtain water-resistant film. The PU/NC coatings and coated films, which were cured at 80°C for 5 min and 2 min, respectively, were investigated by infrared (IR) and ultraviolet (UV) spectroscopy, X-ray diffraction, swelling test, strength test, dynamic mechanical thermal analysis (DMTA), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA). The results show that the crosslink densities of the PU/NC semi-IPNs were smaller than that of pure PU, and decreased with the decrease of Mη of nitrocellulose (NC Mη), indicating NC molecules cohered intimately with PU, and hindered the PU network formation. The physical and mechanical properties of the films coated with PU/NC coatings were significantly improved. With the increase of NC Mη, the strength and thermal stability of the coated films increased, but the pliability, water resistivity, and optical transmission decreased slowly. The PU/NC coating with low NC Mη more readily penetrated into the RC film, and reacted with cellulose, resulting in a strong interfacial bonding and dense surface caused by intimate blend of PU/NC in the coated films.
|
|
| 7. |
- Zhang, L, et al.
(author)
-
Water-resistant film from polyurethane/nitrocellulose coating to regenerated cellulose
- 1997
-
In: Industrial & Engineering Chemistry Research. - : American Chemical Society (ACS). - 0888-5885 .- 1520-5045. ; 36:7, s. 2651-2656
-
Journal article (peer-reviewed)abstract
- Water-resistant films were obtained from polyurethane (PU)/nitrocellulose coating to regenerated cellulose films, which were prepared by coagulating cellulose cuoxam solution. The PU/nitrocellulose coating layer was cured at 80 degrees C for 2 min and formed semi-interpenetrating polymer networks (semi-IPNs) structure. The tensile strength (sigma(b)), water resistivity (R), water vapor permeability (P), and light transmittance of the coated films changed with nitrocellulose content in the coating, and the best values (such as sigma(b), 679 kg.cm(-2); R, 53%; P, 0.004 g.cm(-2).day(-1)) were attained at 33 wt % nitrocellulose. The TEM, EPMA, DTA, IRI and UV results-showed that the coated films have strong interfacial bonding, which is caused by covalent and hydrogen bonds between the cellulose film and the semi-IPNs coating. The biodegradation half-life t(1/2) of the coated films in soil at 20-30 degrees C was given to be 58 days, and after about 6 months the coated films were almost completely decomposed by microorganisms. SEM and the kinetics of decay studied on the biodegradability were discussed. The water-resistant films coated with PU/nitrocellulose have promising application where biodegradation is important.
|
|
| 8. |
- Chen, Min, et al.
(author)
-
Highly stable and efficient all-inorganic lead-free perovskite solar cells with native-oxide passivation
- 2019
-
In: Nature Communications. - : Nature Publishing Group. - 2041-1723. ; 10
-
Journal article (peer-reviewed)abstract
- There has been an urgent need to eliminate toxic lead from the prevailing halide perovskite solar cells (PSCs), but the current lead-free PSCs are still plagued with the critical issues of low efficiency and poor stability. This is primarily due to their inadequate photovoltaic properties and chemical stability. Herein we demonstrate the use of the lead-free, all-inorganic cesium tin-germanium triiodide (CsSn(0.5)Ge(0.5)l(3)) solid-solution perovskite as the light absorber in PSCs, delivering promising efficiency of up to 7.11%. More importantly, these PSCs show very high stability, with less than 10% decay in efficiency after 500 h of continuous operation in N-2 atmosphere under one-sun illumination. The key to this striking performance of these PSCs is the formation of a full-coverage, stable native-oxide layer, which fully encapsulates and passivates the perovskite surfaces. The native-oxide passivation approach reported here represents an alternate avenue for boosting the efficiency and stability of lead-free PSCs.
|
|
| 9. |
- Li, Y., et al.
(author)
-
A Decision-making Framework for the Site Selection of PV Deployment along High-speed Railway
- 2021
-
In: Energy Proceedings. - : Scanditale AB.
-
Conference paper (peer-reviewed)abstract
- The development of photovoltaic industry can effectively alleviate the energy crisis and environmental pollution. The deployment of photovoltaic power stations along the high-speed railway is a new mode combining photovoltaic new energy with infrastructure. This paper constructs a comprehensive decision-making framework for the site selection of PV power station along high-speed railway combining the subjective method and the objective method. A scientific and reasonable evaluation index system comprehensively considering multiple factors is constructed in this framework. Analytic hierarchy process and Entropy weight method are combined to determine the weight of every index, which combines the expert knowledge and data information effectively, relatively reducing systematic error and random error. Grey relational analysis is used to choose scheme among several alternatives, which greatly deal with the strong grey correlations among indexes. The framework established in this paper is used to select PV power stations along the Beijing-Shanghai high-speed railway, which also verifies the effectiveness of the framework.
|
|
| 10. |
- Rueda, L., et al.
(author)
-
Isocyanate-rich cellulose nanocrystals and their selective insertion in elastomeric polyurethane
- 2011
-
In: Composites Science And Technology. - : Elsevier BV. - 0266-3538 .- 1879-1050. ; 71:16, s. 1953-1960
-
Journal article (peer-reviewed)abstract
- Cellulose nanocrystals (CNC) were successfully obtained and modified with 1,6-hexamethylene diisocyanate (HE)!) by means of in situ polymerization varying the CNC/HDI molar ratio to evaluate the number of anchored chains to the CNC. The modification was examined by elemental analysis, nuclear magnetic resonance ((13)C NMR) and attenuated total reflection Fourier transform infrared spectroscopy (IR-ATR). Nanocomposites containing 1.5 wt% CNC, modified and unmodified, were prepared by solvent casting. Thermal and mechanical properties of the resulting films were evaluated from the viewpoint of polyurethane microphase separated structure, soft and hard domains. CNC were effectively dispersed in the polyurethane matrix and depending on surface chemistry, the nanoreinforcement interacts selectively with matrix nanodomains. This interpretation is supported by differences in thermal and mechanical properties of the nanocomposites and also confirmed by AFM images. Isocyanate rich cellulose nanocrystals interacted with matrix hard phase, promoting physical association with hard segments, enhancing stiffness and dimensional stability versus temperature of the nanocomposite.
|
|
