Horizontal Alignment Research Articles

Optimal bi-planar gradient coil configurations for diamond nitrogen-vacancy based diffusion-weighted NMR experiments

IntroductionDiffusion weighting in optically detected magnetic resonance experiments involving diamond nitrogen-vacancy (NV) centers can provide valuable microstructural information. Bi-planar gradient coils employed for diffusion weighting afford excellent spatial access, essential for integrating the NV-NMR components. Nevertheless, owing to the polar tilt of roughly 55^{circ } of the diamond NV center, the primary magnetic field direction must be taken into account accordingly.MethodsTo determine the most effective bi-planar gradient coil configurations, we conducted an investigation into the impact of various factors, including the square side length, surface separation, and surface orientation. This was accomplished by generating over 500 bi-planar surface configurations using automated methods.ResultsWe successfully generated and evaluated coil layouts in terms of sensitivity and field accuracy. Interestingly, inclined bi-planar orientations close to the NV–NMR setup’s requirement, showed higher sensitivity for the transverse gradient channels than horizontal or vertical orientations. We fabricated a suitable solution as a three-channel bi-planar double-layered PCB system and experimentally validated the sensitivities at 28.7 mathrm mT/m/A and 26.8 mathrm mT/m/A for the transverse G_{x} and G_{y} gradients, and 26 mathrm mT/m/A for the G_{z} gradient.DiscussionWe found that the chosen relative bi-planar tilt of 35^{circ } represents a reasonable compromise in terms of overall performance and allows for easier coil implementation with a straight, horizontal alignment within the overall experimental setup.

Interphase Modulated Early-Stage Zn Electrodeposition Mechanism.

Zn electrodeposition mechanism is a cornerstone of dendritic issue exploration in Zn-ion battery. Investigation of the inherent early-stage Zn plating kinetics and its dependence on the reactivity of anode-electrolyte interphase is crucial. Herein, the kinetic evolution of Zn plating on three characteristic substrates is quantified: fresh Zn, commercial Zn foil, and Zn foil with spontaneously generated solid-electrolyte interphase (SEI). Using scanning electrochemical microscopy analysis, the original interphase regulation of Zn deposit orientation and the competitive reaction between Zn deposition and SEI passivation are studied in situ. Furthermore, the SEI layer can suppress the dendrite growth at initial state by guiding the horizontal alignment of Zn flakes and promote Zn plating process. This approach provided a feasible consideration into interphase engineering of various metal anodes.

Full-thickness skin rejuvenation by a novel dual-length microneedle radiofrequency device: A proof-of-concept study using human skin.

A novel dual-length microneedle radiofrequency (DLMR) device has been developed to achieve full-thickness skin rejuvenation by stimulating the papillary and reticular dermis simultaneously. This device's dual-level targeting concept need to be validated on human skin, although its clinical efficacy has been demonstrated in a previous study. This study evaluated the dual-depth targeting capability and the ability to induce rejuvenation in each layer of vertical skin anatomy, that is, the epidermis, papillary dermis, and reticular dermis, using full-thickness human facial skin samples. Human facial skin samples were obtained from 13 Asian patients who had facelift surgery. To validate the dual-depth targeting concept, DMLR-treated skin samples were analyzed using a digital microscope, thermal imaging, and hematoloxylin and eosin (H&E) staining immediately after DLMR application. On samples stained with H&E, Masson's tricrome, and Verhoeff-Van Gieson, histological observation and morphometric analysis were performed. Total collagen assay (TCA) and quantitative real-time polymerase chain reaction (qPCR) were used to assess changes in total collagen content and mRNA expression levels of collagen types I/III and vimentin, respectively. The DLMR device successfully induced thermal stimulation in the papillary and reticular dermis. The thickness, stacks, and dermal-epidermal junction convolution of the epidermis treated with DLMR were significantly increased. Collagen bundles in the dermis treated with DLMR exhibited a notable increase in thickness, density, and horizontal alignment. Dermal collagen levels were significantly higher in the morphometric and TCA data, as well as in the qPCR data for dermal matrix proteins. Our DLMR device independently and precisely targeted the papillary and reticular dermis, and it appears to be an effective modality for implementing full-thickness rejuvenation.

Estimating accident-prone freeway sections: simulation and accident prediction model

Accident-prone sections are usually the most dangerous areas on a freeway. Identifying and studying them is therefore very important. In this study, accident-prone sections were estimated using a 77 km long freeway section in Zhejiang province, China as an example. Accident data and horizontal alignment data of the freeway were obtained. Two statistical methods – the improved cumulative frequency method considering equivalent accident numbers and the accident matrix method – were used to identify the accident-prone sections of the freeway. Additionally, a new method that combines vehicle dynamic simulation (using the CarSim software program) and speed consistency theory was developed and used to estimate the accident-prone sections of the freeway. To provide design advice, an accident prediction model was established by analysing the relationships between horizontal alignment geometric parameters and accident data. Shown to have a certain reliability, the proposed method can be used by designers to verify the safety condition of newly designed freeways and thus enhance freeway safety. The established model, which is logically reasonable and has a certain precision, could be a valuable reference for freeway designers.

Lithium-Induced Reorientation of Few-Layer MoS2 Films.

Molybdenum disulfide (MoS2) few-layer films have gained considerable attention for their possible applications in electronics and optics and also as a promising material for energy conversion and storage. Intercalating alkali metals, such as lithium, offers the opportunity to engineer the electronic properties of MoS2. However, the influence of lithium on the growth of MoS2 layers has not been fully explored. Here, we have studied how lithium affects the structural and optical properties of the MoS2 few-layer films prepared using a new method based on one-zone sulfurization with Li2S as a source of lithium. This method enables incorporation of Li into octahedral and tetrahedral sites of the already prepared MoS2 films or during MoS2 formation. Our results discover an important effect of lithium promoting the epitaxial growth and horizontal alignment of the films. Moreover, we have observed a vertical-to-horizontal reorientation in vertically aligned MoS2 films upon lithiation. The measurements show long-term stability and preserved chemical composition of the horizontally aligned Li-doped MoS2.

Road Accident Hotspots on Jordan’s Highway Based on Geometric Designs Using Structural Equation Modeling

One of the primary objectives of transportation engineering is to increase the safety of road infrastructure. This study seeks to determine the relationship between geometric design parameters in relation to road accident criteria based on accident hotspots on Jordan’s Desert Highway. The road accident data (from 2016 to 2019) were collected from the Jordan Traffic Department. The spatial pattern of hotspots was identified using a GIS tool named Getis-Ord Gi* based on the severity index of road accidents. A topographic survey was conducted to investigate the road alignment and intersections at hotspot locations. The study utilized the Structural Equation Modeling (SEM) technique via SmartPLS to highlight the correlation between geometric designs in relation to road accidents. The hotspot analysis (Gits-Ord Gi) discovered 80 road accident hotspots along the highway. The study found that horizontal alignment and road intersections significantly impact road accidents in hotspot locations. Furthermore, vertical alignment has no effect on road accidents in hotspot areas. The study enhanced the comprehension of the factors associated with road geometrics and intersections that affect the occurrence of road accidents.

Influence of design parameters on beam-to-column connections of steel storage rack systems

Storage rack systems are the products of cold-formed steel material. Increase in the volume of distant sale in recent years has also increased the importance of logistics and storage industry. In steel storage racks, plug-in beam-end connectors are used to produce boltless and semi-rigid beam-to-column connections. Variability of tab designs for beam-end connector makes it heavily difficult to develop a generalized analytical model. For some typical connectors, several analytical models are available to evaluate the performance of connections. In this study, sixteen beam-to-column connection tests were conducted on a commercially available pallet rack assembly by varying the most effective parameters such as the wall-thickness of the column section, height of the beam, vertical beam position on the connector, and installation of the bolts at connector level among the opening of the column. Being the main goals of this study, failure mechanisms and moment-rotation effects of changing vertical position of the beam on the connector and placing bolts among the opening of the column at the horizontal alignments of the connector, were investigated. These experimental results have shed light on how the ultimate moment capacity, rotational stiffness and rotational ductility values ​​vary by changing these design parameters. In the light of these results, an analytical model has been proposed in order to predict the structural behavior of beam-to-column connections with an acceptable accuracy.

Матричная модель кооперативного перевода

The article deals with modelling the translation process performed in the frameworks of a translation project in a team that consists of translators and experts from related fields. This type of collaborative activity is denoted by the term "cooperative translation" studied from the perspective of the integrative approach and synergetics. The cooperative translation of a photo album, which describes museum exhibits was chosen as the material for the study. The analysis of the operational processes of the project is presented by means of a matrix model in two variants: an organizational matrix and a responsibility matrix. Both models imply the intersection of horizontal and vertical alignment of management and communication levels with a description of the roles of participants, their position in the project matrix structure, characteristics of functional responsibilities and the degree of involvement in the project. The authors proposed a hypothesis about the effectiveness of the matrix format for visualizing operational processes in cooperative translation activities and adapting the communication flows between the participants, which is validated by empirical data. The findings confirm the practicality of the modelling and mapping methodology to describing cooperative activities within a translation project. The article indicates further directions that work should take including a deeper analysis of cooperative translation from a cognitive perspective with reference to embodied cognition of a related research area.

Miniaturized Annular Sensor Aids in Well Integrity, Production Monitoring

_ This article, written by JPT Technology Editor Chris Carpenter, contains highlights of paper OTC 31160, “Intelligent Pipe: A New Monitoring Solution for Your Wells,” by Francois-Xavier Bulard, Vallourec; Emmanuel Tavernier, OpenField Technology; and Antoine Deroubaix, Vallourec, at al. The paper has not been peer reviewed. Copyright 2021 Offshore Technology Conference. Reproduced by permission. _ The integration of a pressure and temperature sensor element in tubulars is possible as the result of microelectromechanical systems (MEMS) technology. Low-power consumption combined with an adapted transmission technology allows use of this technology inside an oil and gas well. Operators can use embedded sensors to access previously inaccessible well areas in real time. The qualification of this technology is completed to ensure the integrity of the system and its long-term viability. The complete paper presents the development, qualification, and applications of an intelligent tube solution using the described technology. Technology Description The development of this solution was the result of a partnership between OpenField Technology and Vallourec. While one section of the complete paper is dedicated to qualification tests performed during the development of the intelligent-pipe solution, this synopsis concentrates on the design of the solution and its potential deployment. The concept involves positioning a microsensor on the outside of a mandrel that can measure nearby annulus pressure, temperature fluids, or formation behavior. This system is composed of a pressure and temperature sensor connected to a battery module and a transmitting coil. This system (sensor, battery, and coil) is doubled to meet customer requirements for redundancy. Each mandrel contains two distinct monitoring modules. Positioned in each string of a well, this monitoring module tracks pressure and temperature changes at different depths throughout the well life cycle. This module is simple to install and is run with the casing string like any other oil and gas tubular-goods pipe. This module is set up for the entire life of the well, with two options for data retrieval: a temporary option with the use of a logging tool and a permanent option with the use of a specific tubing-transmission mandrel (Fig. 1). This tubing-transmission mandrel is connected to the surface by an electrical cable and designed to permanently supply power to the other casing module located at the same depth. The tubing-transmission mandrel furthermore ensures data retrieval from each sensor. The operating principle of the solution is based on the fact that each casing module is connected by an electromagnetic field to a logging tool or a tubing-transmission mandrel. This electromagnetic link is ensured by using a nonmagnetic (high-alloy) material for the casing module. This nonmagnetic material allows the electromagnetic field to pass from the tubing string up to the larger casing where monitoring is performed. It defines the horizontal transmission of the solution (as opposed to the vertical transmission) that is ensured by the use of a permanent downhole electrical cable connected to the surface. This cable brings power from the surface to the tubing-transmission mandrel in the case of deployment of the permanent option for data retrieval and allows data retrieval from the monitoring devices connected to this tubing mandrel. Horizontal transmission is only ensured if the different tubing and casing mandrels meet certain horizontal alignment tolerances.

Testing the Dynamics of Flight for the Products of Explosion for a Warhead with a Weight of 250 kg

This study presents the results of the testing of the explosion process of a warhead with a weight of 250 kg, filled with 87 kg of TNT with 20% of aluminium dust, in two configurations: with horizontal and vertical alignment of the warheads longitudinal axis, and with the centre of length of the warhead body located at a height of approx. 1 m above the ground. Four warheads were detonated in each configuration. The horizontal configuration allowed the collection of some amount of the fragments from the ground, with sizes and spatial distribution of the fragments corresponding to the location on the body from which they came, with the largest fragments from the central part of the shell measuring approximately 9 30 280 mm. For the vertical configuration, the warheads nose was pointed downwards, with an up-down excitation. In both configurations, the explosion process was recorded from a distance of 300 m using a PHANTOM fast camera with a time resolution (frame interval) of 55 s to 133 s: for the horizontal configuration along the bodys longitudinal axis, for the vertical configuration perpendicular to this axis. In the vertical configuration, the bodys expansion process was recorded using short-circuit sensors spaced every 5 mm along the flight radius. The sensors sent short-circuit signals to the time meter, whereas the first sensor was installed at a distance of approx. 1 mm from the body surface and was used to initiate the processes of time counting and recording the overpressure diagrams over time at the front of the explosion/shock (FU) wave. The recorded expansion velocity was approx. 1300 m/s, with the shell radius increasing by 20 mm. Overpressure at the front of the FU was measured by PCB pencil-tip piezoelectric sensors (CzP). Every sensor had two active surfaces arranged in tandem at a distance of 100 mm, which made it possible to determine the local FU velocity. Signals from CzP were recorded every 200 ns using a DEWETRON recorder with software allowing their initial and further processing. Three sensors were spaced 8 m from each other, whereas the first was located 8 m to 10 m from the warheads longitudinal axis. Under a row of the sensors a thick-wall steel pipe was placed to protect the sensors from destruction by the fragments. The determined local FU velocities varied from approx. (590 m/s to 740 m/s) at a distance of approx. 8 m from the epicentre up to approx. 370 m/s at a distance of approx. 26 m from the epicentre; the overpressure measured values varied from approx. (230 kPa to 550 kPa) at a distance of approx. 8 m to approx. 22 kPa at a distance of approx. 26 m from the epicentre; satisfying conformance of the velocity and pressure values under the flat FU model was found. The FU trajectory was also taken from the video recording the velocities measured varied from approx. 2,650 m/s at a distance of 0.3 m to approx. 670 m/s at a distance of 6 m from the epicentre, which corresponds to the CzP data. The fragments flying next to the CzP, generally with the highest mass to effective transverse surface ratio, left traces of their conical FU on the CzP overpressure records, which allowed the determination of average velocities for some of them across the access path to the CzP, whereas these velocities ranged from approx. 1700 m/s at a distance of approx. 8 m and (1500 m/s to 1600 m/s) at a distance of 16 m to approx. 1300 to 1400 m/s at a distance of 26 m from the epicentre. Average access velocities of the selected fragments to the field marks were determined on the basis of the video recording ranged from approx. 1800 m/s at a distance of 5 m to approx. 1500 m/s at a distance of 20 m from the explosion epicentre.

Generalized Kendrick analysis for improved visualization of atmospheric mass spectral data

Abstract. Mass spectrometry is an important analytical technique within the field of atmospheric chemistry. Owing to advances in instrumentation, particularly with regards to mass-resolving power and instrument response factors (sensitivities), hundreds of different mass-to-charge (m/z) signals are routinely measured. This large number of detected ions creates challenges for data visualization. Furthermore, assignment of chemical formulas to these ions is time consuming and increases in difficulty at the higher m/z ranges. Here, we describe generalized Kendrick analysis (GKA) to facilitate the visualization and peak identification processes for typical atmospheric organic (and to some extent inorganic) compounds. GKA is closely related to resolution-enhanced Kendrick mass defect analysis (REKMD), which introduces a tunable integer into the Kendrick equation that effectively contracts or expands the mass scale. A characteristic of all Kendrick analysis methods is that these changes maintain the horizontal alignment of ion series related by integer multiples of the chosen base unit. Compared to traditional Kendrick analysis, GKA and REKMD use a tunable parameter (“scaling factor”) to alter the mass defect spacing between different homologue ion series. As a result, the entire mass defect range (−0.5 to 0.5) is more effectively used simplifying data visualization and facilitating chemical formula assignment. We describe the mechanism of this transformation and discuss base unit and scaling factor selections appropriate for compounds typically found in atmospheric measurements. We present an open-source graphical user interface (GUI) for calculating and visualizing GKA results within the Igor Pro environment.

Furthering innovation management via mutual amplification of vertical and horizontal fit: analysis of a case study

PurposeDoes the simultaneous vertical and horizontal alignment of HR systems positively impact innovation? The authors use the “innovation value chain” model to explore the interplay between the central strategic human resource management concepts of vertical and horizontal fit of HR systems and their role in positively impacting product innovation management.Design/methodology/approachThe authors use the findings from a case study of a large multinational organization in the high-tech sector for the present study. In the first phase, the authors analyse responses to 20 qualitative interviews with senior business and HR executives at the organization using the grounded theory approach. In the second phase, the authors analysed six years of performance ratings and salary data for 4,500–5,500 employees.FindingsPhase 1 of the study established the importance of innovation management as a strategic priority and the role of vertical and horizontal fit of HR systems and practices in positively impacting innovation management. Phase 2 reinforced the findings from Phase 1 by demonstrating the vertical and horizontal fit of the performance and compensation management processes towards furthering innovation management. Our study findings suggest that both forms of fit boost innovation management and interact to reinforce each other mutually, magnifying their respective positive effects towards improving innovation management.Originality/valueWhile past studies have generally focused on the isolated role of either the HR system or that of a bundle of HR practices on innovation, the present study empirically demonstrates the simultaneous role of vertical and horizontal fit of HR systems and practices in furthering innovation management. The authors use interviews with senior executives and objective performance and salary data to provide the first experimental evidence of the mechanism of the interplay between the two forms of fit.

Modeling of drill string dynamics in directional wells for real-time simulation

Simple and computationally efficient drill string models running real-time describing motion in all axes in directional wells are important for the implementation of closed-loop control and assisted monitoring during drilling operations. This paper proposes a new simplified three-dimensional model based on a parametric curve and lumped-parameter modeling, where Kane’s method is used to establish the equations of motion. Validation of the steady-state motion and convergence for the lumped model in vertical and horizontal alignment was compared with a finite-element model. The configuration and restoring forces show good results compared with finite-element analysis. Hence, the model demonstrate the axial contraction as a function of the body restoring forces being oriented to the inertial frame, inherently producing nonlinear coupled axial tension forces. The qualitative response of the model is confirmed in simulation case studies, being showcased by a deviated J-well configuration. Traveling block velocity and top drive torque are included as actuated inputs to analyze off-bottom friction and contact along the wellbore. The model is proposed to act as a virtual sensor for drilling directional wells.

Analysis of Driving Fatigue Characteristics in Cold and Hypoxia Environment of High-Altitude Areas.

The cold and hypoxic environment at high altitudes can easily lead to driving fatigue. For improving highway safety in high-altitude areas, a driver fatigue test is conducted using the Kangtai PM-60A car heart rate and oxygen tester to collect drivers' heart rate oximetry in National Highway 214 in Qinghai Province. Standard deviation (SDNN), mean (M), coefficient of RR (two R heart rate waves), RR interval coefficient of variation (RRVC), and cumulative rate of driving fatigue based on the driver's heart rate RR interval are calculated using SPSS. This study aims to derive degree of driving fatigue (DFD) in high-altitude areas when driving from lower to higher altitude. The analysis shows that the DFD growth trend of different altitude ranges presents an S-shaped curve. The driving fatigue thresholds in the altitude range of 3000-3500, 3500-4000, 4000-4500, and 4500-5000 m are 2.86, 3.82, 4.54, and 10.2, which are significantly higher than that of ordinary roads in plain areas. The start times of severe fatigue in the four altitude ranges are 35, 34, 32, and 25 minutes. The start time of driving fatigue continued to advance with the increase of age, and the DFD continued to increase with the increase of age. Results provide an empirical basis for the design of the horizontal alignment index system and antifatigue strategies to improve highway safety in high-altitude areas.

How does climate-smart agriculture contribute to global climate policy? Bridging the gap between policy and practice

The Paris Agreement, which entered force in 2016, requires involved Parties to submit Nationally Determined Contributions (NDCs). Today, it is well known that global agriculture both contributes to, and is affected by, the changing climate, which calls for an integrated role of farming in climate policy formation. Currently, different efforts aim to increase agricultural productivity, and to mitigate and adapt to climate change through the use of climate-smart agriculture (CSA). However, the efficacy of CSA in contributing to the NDCs has been the subject of debate. In this study, we studied the implementation and alignment of CSA and NDCs in two contrasting case-study non-Annex-I countries that are well known for their efforts in implementing CSA, namely Ethiopia and Colombia. We found that CSA can be a useful approach to reaching the climate goals outlined in the NDCs in the agriculture sector, specifically when used in the planning process to ensure the integration of its elements—adaptation, mitigation, and productivity—in sectoral activity. At the same time, the NDCs, which influence subsequent policy development, also offer an opportunity to increase the usage of CSA as an approach by integrating it more fully into national strategies. However, the incorporation of CSA into national-level climate policies is difficult due to myriad challenges, such as a lack of horizontal and vertical alignment, limited capacity and funding, and highly complex and varying contexts in which the policies are being developed. This research analyzes to what extent CSA is utilized as an approach to fulfilling the NDCs in Ethiopia and Colombia, and identifies entry points to further its use in different contexts.

Design Issues in Widening of Unspiraled Horizontal Curves

In highway alignment, when the traveled way is widened for unspiraled horizontal curves, a linear increase, widening from zero to its maximum value along the application length, leads to an undesired straight edge or an apparent kink, since there is no transition curve between the tangent section of the road and the main circular curve (unlike spiraled horizontal alignment where gradual and proportional offsets of widening can easily be accomplished with respect to the transition curve). Although compound curves or modified spirals can be employed to solve this problem, using complex curves for simple (unspiraled) alignment has not been a favored approach. This paper addresses this issue and proposes using a single circular arc on the inside edge of widening where possible. On trying many circular arcs iteratively until certain conditions are met, within a given range of superelevation runoff length, several arcs have been produced for each cell of the widening table provided by AASHTO. All the arcs satisfied the all-governing condition of sharing the same tangent with the main circular curve at the end of the application distance. Provided that the superelevation runoff length falls within the limits determined in the paper, the work presents a simple and time saving approach for designers to adapt. Although the computations are based on 7.2 m traveled way width, similar arcs can easily be produced by others for various widths. The paper, therefore, shows how to map the application domain of such arcs for given curve parameters.

A Recommendation Model for Highway Horizontal Curve Indicators Based on Machine Learning

The horizontal alignment design is the result of the designer’s comprehensive consideration of smooth alignment and satisfying multiple design goals such as safety, environmental protection and economy.Through analyzing a large number of highway horizontal design cases,the statistical laws of intersection spacing, declination angle and the relationship between them are introduced. Based on this and the machine learning algorithms, a horizontal basic curve indicator recommendation model suitable for the single intersection design and the double intersection design process is built. Finally, the reliability of the model is verified and evaluated by using the calculation accuracy, test set error and average difference.

Automatic Design of the Horizontal Alignment of a Road Interchange: The Case of a Trumpet-Type

This paper investigated the automatic design of road interchanges in the framework of mathematical optimization. To introduce the approach, we focused on a trumpet-type interchange, and specifically on S-type and loop ramps. By analyzing all geometric elements, we propose a geometrical model that provides, from an appropriate decision vector, a complete parametrization of the ramps. We established safety and spatial constraints (including restrictions on passage through forbidden areas) and formulated a nonlinear optimization problem, the numerical solution of which gives the design of the interchange ramps. The goodness of the model and the accuracy of the method proposed for its numerical resolution was checked using an academic problem designed so that its solution can be analyzed easily. Finally, the practical usefulness of this methodology was shown in a real case study, redesigning an existing interchange on a Spanish highway.

Data Mining Modeling Feasibility Patterns of Graduates Ability With Stakeholder Needs Using Apriori Algorithm

This The speed of information, the accuracy of data, the ease of information services, and accountability are very important reasons for the implementation of the system. Semarang University (USM) is a private university in Semarang that has the most 2 students in Central Java. Based on the 2019 USM tracer data showing horizontal alignment, namely how close the relationship between the field of study and alumni work is, it appears that there is still a discrepancy in the ability of graduates with stakeholders. The Apriori algorithm is the best-known algorithm for finding high-frequency patterns Rules that state associations between attributes are often called affinity analysis or market basket analysis. The use of the Apriori Algorithm in data mining calculations using data from the Semarang University tracer that the limit of the minimum support is 50% and the minimum confidence is 100% so that it forms 4 rules. From the four rules produced that modeling using the Apriori Algorithm can produce several rule formations so that it can provide an evaluation to the University for compiling steps, this can be seen because the resulting rules are different because each graduate relationship with the desired desires and different styles.

Deep‐Red/Near‐Infrared Delayed Fluorescence Luminophores Based on Dipyrido[3,2‐a:2”,3”‐c]Phenazine‐11,12‐Dicarbonitrile for High‐Performance OLEDs

AbstractDeep‐red (DR) and near‐infrared (NIR) organic light‐emitting diodes (OLEDs) based on purely organic materials hold great potential in various frontier applications, but purely organic DR/NIR materials are far from satisfactory. Herein, a series of tailor‐made delayed fluorescence luminophores comprised of electron‐withdrawing dipyrido[3,2‐a:2″,3″‐c]phenazine‐11,12‐dicarbonitrile and various electron‐donating triarylamines are developed, and their thermal and electrochemical stabilities, electronic structures, photophysical properties and electroluminescence (EL) performances are investigated. They exhibit strong NIR emissions (758−767 nm) in neat films and DR/NIR emissions (680−691 nm) with good photoluminescence quantum yields (48−60%) in doped films, and prefer ordered horizontal alignment with high horizontal dipole ratios of 82−90%, which are attributed to the hybrid transition components of excited states, extended molecular plane and intramolecular hydrogen‐bonding. Their non‐doped OLEDs emit purely NIR light peaking at 820−834 nm with maximum external quantum efficiencies (ηext,maxs) of 0.66−1.06%, and thier doped OLEDs radiate DR/NIR emissions peaking at 656−748 nm with superb ηext,maxs of 14.4–31.0%. They present even better EL performances in sensitized OLEDs, with DR emissions peaking at 648−656 nm and higher ηext,maxs of 29.7−32.9%. These state‐of‐the‐art EL performances demonstrate the great potential of the developed DR/NIR delayed fluorescence luminophores in practical application.