Suitable Alignment Research Articles

Pipeline Embolization Device for Salvage Treatment of a Willis Covered Stent Prolapse Into the Aneurysmal Sac

The Willis covered stent (WCS) may prolapse into the aneurysmal sac due to device migration or foreshortening. We present a useful salvage strategy that can reorient a prolapsed WCS into a more suitable alignment. An intra-procedural prolapse of a WCS into a large cavernous aneurysm occurred in a 70-year-old female patient. A pipeline embolization device (PED) was used to retrieve the WCS and successfully accomplish flow diversion. Maintaining proximal access and ensuring that the microwire is securely held within the central axis of the herniated stent are critical until the entire parent vessel can be reconstructed. This salvage technique may help to regain proximal access and reposition the flow diversion constructs following WCS prolapse.

A framework to aggregate multiple ontology matchers

Purpose Although ontology matchers are annually proposed to address different aspects of the semantic heterogeneity problem, finding the most suitable alignment approach is still an issue. This study aims to propose a computational solution for ontology meta-matching (OMM) and a framework designed for developers to make use of alignment techniques in their applications. Design/methodology/approach The framework includes some similarity functions that can be chosen by developers and then, automatically, set weights for each function to obtain better alignments. To evaluate the framework, several simulations were performed with a data set from the Ontology Alignment Evaluation Initiative. Simple similarity functions were used, rather than aligners known in the literature, to demonstrate that the results would be more influenced by the proposed meta-alignment approach than the functions used. Findings The results showed that the framework is able to adapt to different test cases. The approach achieved better results when compared with existing ontology meta-matchers. Originality/value Although approaches for OMM have been proposed, it is not easy to use them during software development. On the other hand, this work presents a framework that can be used by developers to align ontologies. New ontology matchers can be added and the framework is extensible to new methods. Moreover, this work presents a novel OMM approach modeled as a linear equation system which can be easily computed.

Theoretical design and simulations of hole transporting materials based on 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene for organic-inorganic hybrid perovskite solar cells

2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene represents one of the most effective hole transporting materials in high efficiency perovskite solar cells. Due to the electronic structural diversity of the perovskite material, 20 spirobifluorene derivatives were designed based on the 2,2′,7,7′-tetrakis(N,N-di-p-methoxyphenyl-amine)9,9′-spirobifluorene structural template aiming to achieve suitable energy level alignment with perovskite materials that have lower valence band maximums. The designed molecules aim to obtain better absorption spectrum complementation with low-dimensional perovskite materials to eventually get solar cells with ideal efficiencies. The geometry changes caused by different substitutions of diphenylamine groups, the highest occupied molecular orbital energy level regulations by the introduction of nitrogen atoms and methoxy groups on different sites, the reorganization energy variations and the absorption spectra of all the novel structures were carefully predicated and compared with available experimental data. The relationships between the structural variations and the electronic and energy changes are qualitatively and quantitatively discussed.

Distribution on Warp Maps for Alignment of Open and Closed Curves

Alignment of curve data is an integral part of their statistical analysis, and can be achieved using model- or optimization-based approaches. The parameter space is usually the set of monotone, continuous warp maps of a domain. Infinite-dimensional nature of the parameter space encourages sampling based approaches, which require a distribution on the set of warp maps. Moreover, the distribution should also enable sampling in the presence of important landmark information on the curves which constrain the warp maps. For alignment of closed and open curves in , possibly with landmark information, we provide a constructive, point-process based definition of a distribution on the set of warp maps of [0, 1] and the unit circle , that is, (1) simple to sample from, and (2) possesses the desiderata for decomposition of the alignment problem with landmark constraints into multiple unconstrained ones. For warp maps on [0, 1], the distribution is related to the Dirichlet process. We demonstrate its utility by using it as a prior distribution on warp maps in a Bayesian model for alignment of two univariate curves, and as a proposal distribution in a stochastic algorithm that optimizes a suitable alignment functional for higher-dimensional curves. Several examples from simulated and real datasets are provided.

Effects of stray magnetic field on the performance of ion microbeam

The ion microbeam employing MeV ions has many applications in the fields of elemental analysis, micro/nano processing, ion implantation, irradiation effects of spacecraft, biological irradiation effects, agricultural breeding and so on. The key aims are to reduce the spot size and to improve the stability of spot position. After more than 40 years of development, a variety of well-known factors degrade the performance of ion microbeam with stray magnetic field being one of the key limiting factors. This paper presents a new study of this important problem with the aim of optimizing the approaches to stray field mitigation. An approach applied here was to employ the WinTRAX beam optical software package to model the microbeam spot size and position on the sample to investigate the effects of stray magnetic field. This paper investigated the uniform stray magnetic field model and the non-uniform stray magnetic field model. A suitable alignment of the lenses is useful but only valid for the specific magnetic rigidity of ions and the determined stray DC magnetic field for which the beamline was aligned. This paper proposed a local correction method to address the influences of AC magnetic field and stray DC magnetic field. The method using the WinTRAX to simulate the stray magnetic field in an ion microbeam can estimate the influence once the stray magnetic field is measured in the ion microbeam laboratory.

Molecular design of D-π-D-typed hole-transporting materials for perovskite solar cells based on the π-conjugated cores

Abstract The performances of four new D-π-D-typed hole-transporting materials (HTMs) with big π-conjugated linkers are simulated with density functional theory and the Marcus hopping model. Our results show that the highest occupied molecular orbital (HOMO) levels of new designed HTMs range from −5.22 to −5.39 eV, which presents a suitable energy alignment with the valence band of perovskite. Meanwhile, due to the strong electronic coupling between adjacent molecules and delocalized frontier molecular orbitals, the high hole mobilities are also obtained for these molecules with values of 1.03 × 10−1 cm2v−1 s−1 (L1), 3.67 × 10−2 cm2v−1 s−1 (L2), 1.05 × 10−2 cm2v−1 s−1 (L3), and 3.66 × 10−1 cm2v−1 s−1 (L4), respectively. Moreover, the weak absorption in visible light region and the large Stokes shifts will be also helpful to improve the performance of HTMs. In summary, the calculated results indicate that these new designed molecules with polycyclic π-conjugated cores could become potential HTM candidates to help create more efficient solar cells.

Physicochemical analysis of ion beam-induced surface modifications on polyethylene glycol films for liquid crystal alignment

ABSTRACTWe investigated the surface modification induced by the ion-beam (IB) irradiation of a polyethylene glycol (PEG) film and its liquid crystal (LC) alignment characteristics. The X-ray photoelectron spectroscopy analysis revealed the chemical modification; as the IB incidence angle increased, the number of surface C–O bonds decreased, inducing an anisotropic dipole moment on the PEG film surface. In addition, the physical modification was demonstrated via atomic force microscopy analysis using three-dimensional images as a function of the IB incidence angle. The surface roughness was analyzed; the modification with the smoothest surface was observed for an IB incidence angle of 45°. This modification affected the LC alignment state of the PEG film, as demonstrated by the polarized optical microscopy analysis with pre-tilt angle measurements. Furthermore, for the same IB incidence angle, the residual DC measured using the capacitance–voltage curves was extremely low. Hence, a PEG film irradiated with an IB incidence angle of 45° could be a suitable LC alignment layer.

Amine-Based Interfacial Engineering in Solution-Processed Organic and Perovskite Solar Cells.

Solution-processed organic solar cells (OSCs) and hybrid perovskite solar cells (PvSCs) generally require appropriate transparent electrode with a low work function, which improves the electron extraction, increases the built-in potential, and suppresses charge recombinations. Hence, interfacial modifiers between the cathode and the photoactive layer play a significant role in OSCs and PvSCs, as they provide suitable energy-level alignment, leading to desirable charge carrier selectivity and suppressing charge carrier recombinations at the interfaces. Here, we present a comprehensive study of the energy-level mapping between a transparent electrode and photoactive layers to enhance the electron-transport ability by introducing amine-based interfacial modifiers (ABIMs). Among the ABIMs, polyethylenimine ethoxylated (PEIE) incorporating inverted OSCs shows enhanced power conversion efficiencies (PCEs) from 0.32 to 9.83% due to large interfacial dipole moments, leading to a well-aligned energy level between the cathode and the photoactive layer. Furthermore, we explore the versatility of the PEIE ABIM by employing different photoactive layers with fullerene derivatives, a nonfullerene acceptor, and a perovskite layer. Promisingly, inverted nonfullerene OSCs and planar n-i-p PvSCs with PEIE ABIM show outstanding PCEs of 11.88 and 17.15%, respectively.

Insulating titanium oxynitride for visible light photocatalysis

We propose a systematic approach to obtain various forms of insulating titanium oxynitrides Ti$_{n}$N$_{2}$O$_{2n-3}$ and we conduct a detailed study on its $n=2$ case, Ti$_{2}$N$_{2}$O. We study the energetics and the electronic structures of Ti$_{2}$N$_{2}$O and compare these results with those of pristine and nitrogen-doped TiO$_{2}$ within the framework of the density-functional theory (DFT) and the GW approximation. We find that Ti$_{2}$N$_{2}$O is semiconducting with the calculated band-gap of 1.81 eV, which is significantly smaller than those of pristine TiO$_{2}$ rutile (3.14 eV) or anatase (3.55 eV). Furthermore, the reduction of the band-gap of Ti$_{2}$N$_{2}$O is realized not by lowering of the conduction-band minimum but by rising the valence-band maximum. Therefore the proposed Ti$_{2}$N$_{2}$O has suitable band-edge alignment for water-splitting photocatalysis. Finally, total energy calculations indicate that Ti$_{2}$N$_{2}$O is potentially easier to synthesize than nitrogen-doped TiO$_{2}$. Based on these results, we propose Ti$_{2}$N$_{2}$O as a promising visible-light photocatalytic material.

Efficient Production of Phosphorene Nanosheets via Shear Stress Mediated Exfoliation for Low‐Temperature Perovskite Solar Cells

AbstractA simple and fast “top‐down” protocol is introduced herein to prepare solution processable few‐layer phosphorene nanosheets using vortex fluidic mediated exfoliation under near‐infrared (NIR) pulsed laser irradiation. This novel shear‐exfoliation method requires short processing times and produces highly crystalline, atomically thin phosphorene nanosheets (4.3 ± 0.4 nm). The as‐prepared phosphorene nanosheets are used as an effective electron transporting material (ETM) for low‐temperature processed, planar n‐i‐p perovskite solar cells (PSCs). With the addition of phosphorene, the average power conversion efficiency (PCE) increases from 14.32% to 16.53% with a maximum PCE of 17.85% observed for the phosphorene incorporated PSCs which is comparable to the devices made using the traditional high‐temperature protocol. Experimental and theoretical (density‐functional theory) investigations reveal the PCE improvements are due to the high carrier mobility and suitable band energy alignment of the phosphorene. The work not only paves the way for novel synthesis of 2D materials, but also opens a new avenue in using phosphorene as an efficient ETM in photovoltaic devices.

17.78% efficient low-temperature carbon-based planar perovskite solar cells using Zn-doped SnO2 electron transport layer

Organic-inorganic lead halide perovskite solar cells have garnered enormous interest in scientific communities due to comparable power conversion efficiencies and solution-processed fabrication techniques. Among them, carbon-based perovskite solar cells seem to be one of the most promising candidates for addressing the stability issue while suffering from inferior efficiency or high processing temperature. Herein, we introduce low-temperature processed Zn-doped SnO2 (below 200 °C) as an effective electron transport layer in perovskite solar cells for the first time, and demonstrate a low-temperature carbon-based device with Cu-phthalocyanine as hole transport layer. We find that Zn doping contributes to a more suitable energy level alignment and an improved conductivity for SnO2 films. As a result, the electron transfer and extraction are enhanced and the charge recombination is suppressed. In addition, devices with Zn-doped SnO2 have a wider depletion region, leading to an enhanced photovoltaic performance. An optimal efficiency of 17.78% can be obtained after 2 mM Zn doping. Furthermore, these devices, introducing highly stable and hydrophobic Cu-phthalocyanine and carbon, maintain almost 100% of their initial efficiencies over 1200 h in ambient air. Our study paves the way for developing highly efficient and flexible carbon-based perovskite solar cells.

TiO2/SnO2 Nanocomposites as Electron Transporting Layer for Efficiency Enhancement in Planar CH3NH3PbI3-Based Perovskite Solar Cells

Both TiO2 and SnO2 as electron transport layers (ETLs) are the most successful at producing high-efficiency perovskite solar cells (PSCs). Unfortunately, these layers usually require multiple treatments to improve device performance, especially for TiO2-based planar PSCs. Here, a simple, one-step, solution-based method is introduced for fabricating a TiO2/SnO2 nanocomposite ETL. Compared to a pristine TiO2 layer, partial incorporation of SnO2 nanoparticles in a thin compact TiO2 layer contributes to high electrical conductivity and suitable band-level alignment at the ETL/perovskite interface. Using the optimized TiO2/SnO2 nanocomposite ETL, methylammonium lead halide perovskite CH3NH3PbI3-based PSCs exhibit the champion efficiency of 16.8% (area, 0.13 cm2) with less current density–voltage (J–V) hysteresis, which is significantly superior to that of TiO2-based PSCs. Our work highlights that the successful use of TiO2/SnO2 nanocomposite ETL can offer an efficient method for further improvement of the performance for planar PSCs.

Utilization of harmony search algorithm to optimize a cascade for separating multicomponent mixtures

In this paper, a new code, Multicomponent Isotope Separation Cascade Code (MISCC-HS), is developed to calculate the optimal parameters of a cascade for separating multicomponent mixtures. The Harmony Search, HS, algorithm for finding the optimum solution is implemented and developed in the MISCC-HS. Minimizing the total flow rate of a cascade with the prescribed external isotope concentration has been studied. To demonstrate the MISCC-HS capability in converging to the near optimal cascade, the optimization results for the separation of xenon isotopes are compared with the results for the R-cascade that optimized by virtual component variation. MISCC-HS results represent the cascade with fewer centrifuges than the R-cascade. Furthermore, the ability of MISCC-HS is evaluated with other optimization algorithms. Suitable alignment of the results indicates that the use of the HS for this problem guarantees the calculation of the optimal parameters.

Cellular learning automata based bare bones PSO with maximum likelihood rotated mutations

Abstract In this work, a new variant of multi-swarm bare bones PSO is presented which adaptively learns the promising alignments to re-orient its updating distributions. The idea is to maximize the likelihood of generating new particles along appropriate directions. As these alignment directions are unknown a priori, the proposed method employs a learning mechanism for adaptive learning of suitable alignments. The learning mechanism presented in this paper is based on cellular learning automata. Several alignment strategies are developed for each particle in the proposed method, and the cellular learning automata guides the particles toward the most promising directions by adjusting these strategies during the searching process. The new proposed algorithm is compared with a group of stochastic optimization approaches on the CEC2013 benchmark set. Experiential studies suggest the effectiveness of the proposed method in solving complex optimization problems.

Efficiently Improving the Stability of Inverted Perovskite Solar Cells by Employing Polyethylenimine-Modified Carbon Nanotubes as Electrodes.

Inverted perovskite solar cells (PSCs) have been becoming more and more attractive, owing to their easy-fabrication and suppressed hysteresis, while the ion diffusion between metallic electrode and perovskite layer limit the long-term stability of devices. In this work, we employed a novel polyethylenimine (PEI) modified cross-stacked superaligned carbon nanotube (CSCNT) film in the inverted planar PSCs configurated FTO/NiO x/methylammonium lead tri-iodide (MAPbI3)/6, 6-phenyl C61-butyric acid methyl ester (PCBM)/CSCNT:PEI. By modifying CSCNT with a certain concentration of PEI (0.5 wt %), suitable energy level alignment and promoted interfacial charge transfer have been achieved, leading to a significant enhancement in the photovoltaic performance. As a result, a champion power conversion efficiency (PCE) of ∼11% was obtained with a Voc of 0.95 V, a Jsc of 18.7 mA cm-2, a FF of 0.61 as well as negligible hysteresis. Moreover, CSCNT:PEI based inverted PSCs show superior durability in comparison to the standard silver based devices, remaining over 85% of the initial PCE after 500 h aging under various conditions, including long-term air exposure, thermal, and humid treatment. This work opens up a new avenue of facile modified carbon electrodes for highly stable and hysteresis suppressed PSCs.

Angular-Shaped 4,9-Dialkylnaphthodithiophene-Based Octacyclic Ladder-Type Non-Fullerene Acceptors for High Efficiency Ternary-Blend Organic Photovoltaics

An angular-shaped 4,9-didodecylnaphthodithiophene-based octacyclic ladder-type structure was developed. This new ladder-type donor (LD) was coupled with electron-withdrawing IC and FIC units to form two A-LD-A type non-fullerene acceptor materials, NCIC and NCFIC. NCIC and NCFIC as the n-type acceptors are blended with a p-type donor PBDB-T to form the complementary absorption and suitable energy level alignments. The binary-blend PBDB-T:NCIC and PBDB-T:NCFIC devices achieved an efficiency of 7.3% and 7.5%, respectively. PC71BM was incorporated to form D1:A1:A2 ternary blends which further strengthen the absorption at shorter wavelengths. Introduction of PC71BM not only efficiently improves the absorption but also provides multiple channels for exciton dissociation and electron transport to dramatically improve Jsc. It is interesting to find that the Voc of the ternary-blend devices is reversely in proportional to the added amount of PC71BM. The device using the PBDB-T:NCIC:PC71BM (1:1:1 in wt %) showed a...

Improvement of polymer:fullerene bulk heterojunction morphology via temperature and anti-solvent effect

Morphology of polymer:fullerene bulk heterojunctions (BHJ) displays beside suitable energy level alignment between donor and acceptor as well as a sufficient absorption one of the most crucial impacts on organic photovoltaic device efficiency and stability. In particular, the structural order of the polymer phase impacts the charge separation efficiency and transport. In this work we present a comprehensive study on the control of the polymeric order initiated already in solution by using fractions of anti-solvent isopropanol (IPA), and via adjusting the processing temperature for common solutions of an anthracene-containing poly(p-phenylene-ethynylene)-alt-poly(p-phenylene-vinylene) bearing statistically either linear (octyloxy) or branched (2-ethylhexyloxy) side-chains (AnE-PVstat) and phenyl-C61-butyric acid methyl ester (PCBM). Detailed analysis of photophysical data, absorption, and photoluminescence (PL) spectra, of deposited AnE-PVstat:PCBM thin films suggest the formation of J-aggregates for the copolymer to be in strong correlation with the processing formulation (presence of non-solvent IPA) and post-treatment parameters (annealing temperature). The findings for our system indicate that the addition of IPA increases the intermolecular interaction between the polymer chains, consistent with enhanced charge carrier (hole) mobility (μh) in the final film reaching values as high as 10−3 cm2 V−1 s−1. The subtle control of polymer aggregation led to an overall variation in the solar cell device efficiency by about 50%, with optimal processing settings of IPA additive and a solution temperature of 15 °C.

Highly Efficient Perovskite Solar Cells with Gradient Bilayer Electron Transport Materials.

Electron transport layers (ETLs) with suitable energy level alignment for facilitating charge carrier transport as well as electron extraction are essential for planar heterojunction perovskite solar cells (PSCs) to achieve high open-circuit voltage ( VOC) and short-circuit current. Herein we systematically investigate band offset between ETL and perovskite absorber by tuning F doping level in SnO2 nanocrystal. We demonstrate that gradual substitution of F- into the SnO2 ETL can effectively reduce the band offset and result in a substantial increase in device VOC. Consequently, a power conversion efficiency of 20.2% with VOC of 1.13 V can be achieved under AM 1.5 G illumination for planar heterojunction PSCs using F-doped SnO2 bilayer ETL. Our finding provides a simple pathway to tailor ETL/perovskite band offset to increase built-in electric field of planar heterojunction PSCs for maximizing VOC and charge collection simultaneously.

A novel ternary TiO2/CQDs/BiOX (X = Cl, Br, I) heterostructure as photocatalyst for water purification under solar irradiation

A series of novel binary TiO2/BiOX (X = Cl, Br, I) and ternary TiO2/CQDs/BiOBr hybrid photocatalysts were prepared through a facile hydrothermal method. TiO2/BiOX heterostructures were fabricated by varying the halogen ions. The photocatalysts were characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV–Vis diffuse reflectance spectroscopy, and X-ray photoelectron spectroscopy. Among the binary TiO2/BiOX, TiO2/BiOBr showed the most preferable photocatalytic activities due to suitable band gap alignment and photo stability, reaching almost 80% MO degradation during 180 min irradiation under simulated sunlight. Moreover, the effects of synthesis temperature, Ti/Bi ratio on the composition and structure were investigated, the results indicated TiO2/BiOBr with Bi/Ti = 10% prepared at 120 °C possessed the best photocatalytic performance. Carbon quantum dots were introduced to accelerate electrons transfer at interface or prevent charges recombination on the surface, resulting a much better photocatalytic performance for TiO2/CQDs/BiOBr hybrid photocatalysts.

Silaindacenodithiophene‐Based Fused‐Ring Non‐Fullerene Electron Acceptor for Efficient Polymer Solar Cells

AbstractIn this work, a new A‐D‐A type nonfullerene small molecular acceptor SiIDT‐IC, with a fused‐ring silaindacenodithiophene (SiIDT) as D unit and 2‐(3‐oxo‐2,3‐dihydroinden‐1‐ylidene)malononitrile (INCN) as the end A unit, was design and synthesized. The SiIDT‐IC film shows absorption peak and edge at 695 and 733 nm, respectively. The HOMO and LUMO of SiIDT‐IC are of −5.47 and −3.78 eV, respectively. Compared with carbon‐bridging, the Si‐bridging can result in an upper‐lying LUMO level of an acceptor, which is benefit to achieve a higher open‐circuit voltage in polymer solar cells (PSCs). Complementary absorption and suitable energy level alignment between SiIDT‐IC and wide bandgap polymer donor PBDB‐T were found. For the PBDB‐T:SiIDT‐IC based inverted PSCs, a D/A ratio of 1: 1 was optimal to achieve a power conversion efficiency (PCE) of 7.27%. With thermal annealing (TA) of the blend film, a higher PCE of 8.16% could be realized due to increasing of both short‐circuit current density and fill factor. After the TA treatment, hole and electron mobilities were elevated to 3.42 × 10−4 and 1.02 × 10−4 cm2·V−1·s−1, respectively. The results suggest that the SiIDT, a Si‐bridged fused ring, is a valuable D unit to construct efficient nonfullerene acceptors for PSCs.