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Competition between Exceptionally Long‐Range Alkyl Sidechain Ordering and Backbone Ordering in Semiconducting Polymers and Its Impact on Electronic and Optoelectronic Properties
摘要： Intra- and intermolecular ordering greatly impacts the electronic and optoelectronic properties of semiconducting polymers. The interrelationship between ordering of alkyl sidechains and conjugated backbones has yet to be fully detailed, despite much prior effort. Here, the discovery of a highly ordered alkyl sidechain phase in six representative semiconducting polymers, determined from distinct spectroscopic and diffraction signatures, is reported. The sidechain ordering exhibits unusually large coherence lengths (≥70 nm), induces torsional/twisting backbone disorder, and results in a vertically multilayered nanostructure with ordered sidechain layers alternating with disordered backbone layers. Calorimetry and in situ variable temperature scattering measurements in a model system poly{4-(5-(4,8-bis(3-butylnonyl)-6-methylbenzo[1,2-b:4,5-b′]dithiophen-2-yl)thiophen-2-yl)-2-(2-butyloctyl)-5,6-difluoro-7-(5-methylthiophen-2-yl)-2H-benzo[d][1,2,3]triazole} (PBnDT-FTAZ) clearly delineate this competition of ordering that prevents simultaneous long-range order of both moieties. The long-range sidechain ordering can be exploited as a transient state to fabricate PBnDT-FTAZ films with an atypical edge-on texture and 2.5× improved field-effect transistor mobility. The observed influence of ordering between the moieties implies that improved molecular design can produce synergistic rather than destructive ordering effects. Given the large sidechain coherence lengths observed, such synergistic ordering should greatly improve the coherence length of backbone ordering and thereby improve electronic and optoelectronic properties such as charge transport and exciton diffusion lengths.
关键词： semiconducting polymers,organic electronics,polymer crystals,molecular design,alkyl sidechains
更新于2025-09-04 15:30:14
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Critical Considerations on the Clinical Translation of Upconversion Nanoparticles (UCNPs): Recommendations from the European Upconversion Network (COST Action CM1403)
摘要： The unique photoluminescent properties of upconversion nanoparticles (UCNPs) have attracted worldwide research interest and inspired many bioanalytical applications. The anti-Stokes emission with long luminescence lifetimes, narrow and multiple absorption and emission bands, and excellent photostability enable background-free and multiplexed detection in deep tissues. So far, however, in vitro and in vivo applications of UCNPs are restricted to the laboratory use due to safety concerns. Possible harmful effects may originate from the chemical composition but also from the small size of UCNPs. Potential end users must rely on well-founded safety data. Thus, a risk to benefit assessment of the envisioned combined therapeutic and diagnostic (“theranostic”) applications is fundamentally important to bridge the translational gap between laboratory and clinics. The COST Action CM1403 “The European Upconversion Network—From the Design of Photon-Upconverting Nanomaterials to Biomedical Applications” integrates research on UCNPs ranging from fundamental materials synthesis and research, detection instrumentation, biofunctionalization, and bioassay development to toxicity testing. Such an interdisciplinary approach is necessary for a better and safer theranostic use of UCNPs. Here, the status of nanotoxicity research on UCNPs is compared to other nanomaterials, and routes for the translation of UCNPs into clinical applications are delineated.
关键词： nanosafety,lanthanides,research development and innovation (R&D&I),safe-by-design,bioimaging,efficacy quality and safety (EQS),theranostics
更新于2025-09-04 15:30:14
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[IEEE 2018 1st International Cognitive Cities Conference (IC3) - Okinawa, Japan (2018.8.7-2018.8.9)] 2018 1st International Cognitive Cities Conference (IC3) - Relay Lens Design for Image Reduction Applications
摘要： Relay lens is the lens used for transfer an object to the intermediate image plane or directly to enlarge or reduce the object with some magnifications. The design addressed in the study is to reduce an 1mm2 object to 0.5mm image spot size. A Gaussian image theory helps to investigate the initial configuration and potential solutions. The final design reaches high image performance.
关键词： aberration,Lens design,relay lens
更新于2025-09-04 15:30:14
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Reliability of High-Power Mechatronic Systems 1 || Simulation of Degradation Phenomena in Semiconductor Components in order to Ensure the Reliability of Integrated Circuits
摘要： The design cycle until now only guaranteed the electrical performance of integrated circuits (ICs) before aging. Performances throughout product lifetimes are, in general, assured by taking design margins and accelerated aging tests that come in a second complementary phase to guarantee the circuit reliability. In case of degradation, a reactive design correction will necessarily mean a delay in placing the product on the market. The design cycle subject to delay has not yet passed control. This study proposes guaranteeing the level of reliability of an integrated circuit during the design phase. This new design methodology requires a simulation tool for the aging of components. In this phase of the study, reliability tests on manufactured circuits will consolidate the results of reliability simulation up to the point of refining these individualized models by component. Once the components of a technology are properly modeled, the number of reliability incidents must tend towards 0. Marketing is advanced and the design cycle is gaining control. This makes it possible to hope that this technology will be available on the market as soon as the first silicon is available, without having to wait for any accelerated qualification tests. The circuits are guaranteed to be conceptually reliable.
关键词： simulation,design methodology,reliability,integrated circuits,aging
更新于2025-09-04 15:30:14
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[IEEE 2018 7th International Conference on Renewable Energy Research and Applications (ICRERA) - Paris, France (2018.10.14-2018.10.17)] 2018 7th International Conference on Renewable Energy Research and Applications (ICRERA) - From Solar Microgrid Simulation to Field Deployment: Accuracy and Uncertainties
摘要： Economical, stand-alone, solar microgrids can be quickly implemented in most un-electrified regions of the world. Solar resource maps developed by the National Aeronautics and Space Administration (NASA) and the National Renewable Energy Laboratory (NREL), together with HOMER Pro software, have been widely used to determine the optimal design of microgrids. Repercussions of imprecise predictions of solar resources and electrical power generation lead to an increased likelihood of energy shortage in a stand-alone microgrid, or increases overall project costs. Actual solar energy productions of two sites in Kerala, India, were compared with solar electricity generation, predicted by the HOMER Pro tool. For both test sites, the results showed that the simulated, solar production was within 8.1% of the actual annual production. However, monthly variations in solar production led to unanticipated energy shortages in the simulated microgrids. These findings reaffirm the inexorable need of the following actions for cost-effective design of microgrids: a) systematic analysis of reliability of electrical supply, and b) deployment of schemes for demand response and flexible load. Statistical analysis of temporal variation of solar irradiance in the United States were used to inform recommendations for stand-alone microgrid design.
关键词： accuracy,HOMER,solar,resource,model,microgrid,design
更新于2025-09-04 15:30:14
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[IEEE 2018 2nd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - Ankara, Turkey (2018.10.19-2018.10.21)] 2018 2nd International Symposium on Multidisciplinary Studies and Innovative Technologies (ISMSIT) - Optimal Design of a Rooftop Wind-PV Hybrid System to Meet Energy Demand for a Typical Residential Home in 20-Year Lifetime Projection
摘要： The need for electrical power gradually increases every year due to population growth and economic development in particular in developing countries. The primary sources of electricity are usually fossil fuels such as coal, natural gas, oil etc. and major part of them is imported by those countries. This is unfortunately a typical indication of the energy dependence and play strategic role in economic development of the developing countries since some cannot switch to renewable energy use despite they have abundant renewable energy potential. The fact that the use of renewable energy is not widespread in those countries and it can be seen as not making enough investment by the government or private sector. This potential can be utilized by using on-grid/off-grid renewable systems in particular wind-PV systems ranging from power ratings of 1 to 10 kW in remote areas. To make such systems economic, power balance between generation and consumption should be maintained at hourly time slots in the day. One way to do that is to solve a discrete optimization problem and the solution can be achieved by a mathematical model satisfying the given constraints in a certain location. Unit sizing of a low power off-grid renewable system to meet power demand for a typical residential home in a location is achieved and the outcomes are meaningful and encouraging for widening renewable energy applications worldwide.
关键词： electric generation,metaheuristic techniques,optimal design,rooftop wind-PV hybrid system,renewable energy
更新于2025-09-04 15:30:14
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Benzimidazoles in wastewater: Analytical method development, monitoring and degradation by photolysis and ozonation
摘要： Pharmaceutical residues are constantly released into natural waters, mainly from wastewater treatment plants (WWTPs) whose processes are unable to completely eliminate them. Among these drugs, the occurrence of benzimidazoles, a class of antiparasitics for human and veterinary use, has been reported in WWTP e?uents and surface waters. In this study, an SPE-UHPLC-MS/MS method was developed and optimized for extraction and quantitation of benzimidazoles in in?uents and e?uents of a local WWTP and in hospital wastewater. The extraction procedure was optimized using response surface methodology (Box-Behnken design) and the optimal parameters were as follows: 2.0 mL of loading solvent consisting of a mixture of water:methanol (95:5, v/v) and temperature at 43 °C. In hospital wastewater, albendazole (ABZ) and its principal metabolite ricobendazole (RBZ) were the main benzimidazole-related contaminants and were found at concentrations of up to 3810 and 3894 ng L?1, respectively. The WWTP system was able to remove from 46% to 95% of the ABZ quanti?ed in the in?uent, discharging an e?uent with 16–441 ng L?1 of ABZ. The concentrations of other benzimidazoles and metabolites in the WWTP e?uents remained below 350 ng L?1. WWTP e?uents forti?ed with 50 μg L?1 of ABZ and RBZ required 26.7 mgO3 L?1 to remove ABZ and RBZ. After ozonation, the COD and BOD5 of the e?uents were reduced by 27%. Photolysis by UVA radiation was not e?ective to remove ABZ and FBZ from the e?uent samples.
关键词： Antiparasitic,Online SPE-UHPLC-MS/MS,Box-Behnken design,Pharmaceutical residue,Albendazole
更新于2025-09-04 15:30:14
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[IEEE 2018 15th International Multi-Conference on Systems, Signals & Devices (SSD) - Yassmine Hammamet, Tunisia (2018.3.19-2018.3.22)] 2018 15th International Multi-Conference on Systems, Signals & Devices (SSD) - FPA Based Design of 2?l Microstrip Antenna Array for CubeSat Communications
摘要： An important subsystem of a CubeSat is the communication module where microstrip patch antennas are mostly used. The antenna array presented in this paper is devoted to CubeSat communication systems. This paper includes a new approach based on flower pollination algorithm, FPA, for the antenna angular inset-feed and its depth as well as the antenna radius. The designed antenna is a 2x1 circular patch array operating in the S-band (2-4 GHz). Each element of the antenna was fed by the new angular-inset feed technique recently published. This original technique is more effective than conventional inset feed one and provide a more flexibility to improve the impedance matching of the system. The new FPA metaheuristic is used to optimize the performance of each circular patch in terms of return loss, gain and impedance. Here, this antenna array is fed by a compensated power divider having a good impedance matching. The antenna array was simulated by FEKO electromagnetic software. The return loss obtained near the ISM frequency of 2,45 GHz is -27.9663 dB and the simulated gain reached is 9.06 dB
关键词： FPA,Cube-sat,Microstrip antenna arrays,patch antennas,antenna design
更新于2025-09-04 15:30:14
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[Institution of Engineering and Technology 12th European Conference on Antennas and Propagation (EuCAP 2018) - London, UK (9-13 April 2018)] 12th European Conference on Antennas and Propagation (EuCAP 2018) - A Compact Vivaldi Antenna Array for 5G Channel Sounding Applications
摘要： A compact design of phased array Vivaldi antenna for channel sounding applications is proposed. 64-elements of low-profile 22 GHz Vivaldi antennas with coaxial-to-SIW feeds and well-defined end-fire radiation patterns have been used to form an 8×8 planar array design. The antenna elements are designed on 1.6 mm Arlon AD-320 substrates ((cid:304)=3.2 and (cid:303)=0.0038). The structure of SIW is composed of two rows of cylinders between metal plates improve the radiation performance of the which can elements. The proposed phased array antenna has a compact size with frequency response of 21-23 GHz. It has good features in terms of impedance-matching, gain and efficiency characteristics. More than 22 dB realized gain, 23 dBi directivity, and -0.5 dB (90%) total efficiency have been obtained. In addition, the performance of the planar array with different numbers of the radiators has been investigated.
关键词： 5G,channel sounding,phased array design,Vivaldi antenna
更新于2025-09-04 15:30:14
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Mix and Match: Organic and Inorganic Ions in the Perovskite Lattice
摘要： Materials science evolves to a state where the composition and structure of a crystal can be controlled almost at will. Given that a composition meets basic requirements of stoichiometry, steric demands, and charge neutrality, researchers are now able to investigate a wide range of compounds theoretically and, under various experimental conditions, select the constituting fragments of a crystal. One intriguing playground for such materials design is the perovskite structure. While a game of mixing and matching ions has been played successfully for about 150 years within the limits of inorganic compounds, the recent advances in organic–inorganic hybrid perovskite photovoltaics have triggered the inclusion of organic ions. Organic ions can be incorporated on all sites of the perovskite structure, leading to hybrid (double, triple, etc.) perovskites and inverse (hybrid) perovskites. Examples for each of these cases are known, even with all three sites occupied by organic molecules. While this change from monatomic ions to molecular species is accompanied with increased complexity, it shows that concepts from traditional inorganic perovskites are transferable to the novel hybrid materials. The increased compositional space holds promising new possibilities and applications for the universe of perovskite materials.
关键词： hybrid perovskites,inverse hybrid perovskites,materials design,photovoltaic,DFT calculations
更新于2025-09-04 15:30:14