bluuebunny/crossref_metadata_2025_split huggingface dataset:
Main‐Side Chain Hydrogen Bonding‐Based Self‐Healable Polyurethane with Highly Stretchable, Excellent Mechanical Properties for Self‐Healing Acid–Base Resistant Coating
Authors: Xu Heng , Tu Jing , Li Pingyun , Liang Li , Ji Jie , Xiang Guifeng , Li Haozhe , Zhang Yang , Guo Xiaode 
Published: August 2021

AbstractDeveloping an autonomous self‐healing polyurethane (PU) elastomer with excellent mechanical properties and high ductility has attracted increasing attention. Nowadays, the synthesis of elastomers with excellent mechanical properties and rapid self‐healing at room temperature faces a huge challenge. Herein, This work reports a new supramolecular PU with excellent mechanical properties and rapid self‐healing at room temperature through the introduction of T‐type chain extender into the supramolecular polymer chain. The introduction of T‐chain extender can be used to enhance the mechanical strength of PU, and the multiple hydrogen bonds on the side‐chain provide theoretical support for the rapid self‐healing ability of PU. Maximum stress of the synthesized PU can reach 3.4 ± 0.15 Mpa, and maximum elongation at break can reach 3200% ± 160%. Due to flexibility and re‐constructability of side‐chain hydrogen bonds, PU stress repair efficiency can reach 96.7%, and can be self‐healing scratches rapidly and effectively at room temperature. The mechanical properties and self‐healing properties of PU can be adjusted by the content of T‐type chain extender. The PU is applied to the metal surface coating, which has excellent acid–base resistance, bond strength up to 2.9 ± 0.1 Mpa, and the ability to eliminate local damage on the coating surface quickly at room temperature.
Visible Light‐Regulated Heterogeneous Catalytic PET‐RAFT by High Crystallinity Covalent Organic Framework
Authors: Lu Zhen , Yang Hongjie , Fu Xiaoling , Zhao Yulai , Xiao Longqiang , Zhang Zhuofan , Hou Linxi 
Published: August 2021

AbstractCovalent organic frameworks (COFs) are a class of promising photocatalysts for conversing light energy into chemical energy. Based on the tunable building blocks, COFs can be well‐designed as photocatalyst for mediating reversible addition‐fragmentation chain‐transfer (RAFT) polymerization. Herein, 1,3,6,8‐tetrakis(4‐formylphenyl)pyrene (TFPPy) and 2,2″‐bipyridine‐5,5″‐diamine (Bpy) are chosen to construct imine‐based TFPPy‐Bpy‐COFs for catalyzing RAFT polymerization of methacrylates under white light irradiation. The well‐defined polymers with precise molecular weight and narrow molecular weight distribution are obtained. The switch on/off light experiments suggest excellent temporal control toward RAFT polymerization system and the chain‐extension reaction indicates high chain‐end fidelity of macro‐initiators. Mechanism study clarifies that the electron transfer between excited state of TFPPy‐Bpy‐COFs and RAFT agent can form living radicals to mediate polymerization. This methodology provides a novel platform for reversible‐deactivation radical polymerization using COFs as heterogeneous catalysts.
Dynamic Covalent Polyurethane Network Materials: Synthesis and Self‐Healability
Authors: Nellepalli Pothanagandhi , Patel Twinkal , Oh Jung Kwon 
Published: August 2021

AbstractPolyurethane (PU) has not only been widely used in the daily lives, but also extensively explored as an important class of the essential polymers for various applications. In recent years, significant efforts have been made on the development of self‐healable PU materials that possess high performance, extended lifetime, great reliability, and recyclability. A promising approach is the incorporation of covalent dynamic bonds into the design of PU covalently crosslinked polymers and thermoplastic elastomers that can dissociate and reform indefinitely in response to external stimuli or autonomously. This review summarizes various strategies to synthesize self‐healable, reprocessable, and recyclable PU materials integrated with dynamic (reversible) Diels–Alder cycloadduct, disulfide, diselenide, imine, boronic ester, and hindered urea bond. Furthermore, various approaches utilizing the combination of dynamic covalent chemistries with nanofiller surface chemistries are described for the fabrication of dynamic heterogeneous PU composites.
Aminoesterenamide Achieved by Three‐Component Reaction Heading toward Tailoring Covalent Adaptable Network with Great Freedom
Authors: Ma Youwei , Liu Zhiyong , Zhou Shuai , Jiang Xuesong , Shi Zixing , Yin Jie 
Published: August 2021

AbstractCovalent adaptable networks (CANs) have recently received extensive interests due to their reprocessability and repairability. Rethinking the libraries of the published CANs, most of them are fabricated by one/two‐component reactions and few cases utilize multi‐component reactions to construct CANs while multi‐component reactions are conductive to tailoring the properties of polymers due to their structural designability and flexible choice of raw materials. A novel kind of dynamic covalent bond named aminoesterenamide is presented through three‐component reaction between acetoacetyl, amine and isocyanate. Aminoesterenamide exhibits thermal reversibility through dissociating into vinylogous urethane and isocyanate. When it is used to prepare CANs, the synthesized polymer networks can be reprocessed many times via the exchange reaction between aminoesterenamides. Moreover, the forming of aminoesterenamide involving three starting components imparts CANs with great freedom to tailor their properties. Therefore, the authors believe this method that utilizes three‐component reaction to fabricate CANs would bring new stories and perspectives to the exploration of new types of CANs.
Reversible Curvature Reversal of Monolithic Liquid Crystal Elastomer Film and Its Smart Valve Application
Authors: Han Woong Chan , Sim Gun Woo , Kim Young Been , Kim Dae Seok 
Published: August 2021

AbstractBeyond a traditional stimuli‐responsive soft actuator that shows a single motion by a stimulus, multidirectional actuation reversal with a single stimulus is highly required in applications such as shape morphing sensors and soft robotics. Liquid crystal elastomers (LCEs) are one of the most attractive candidates for the soft actuator due to their capability of stimuli‐responsive shape changing in 3D, which is programmable with local orientation of LC mesogens. Here, a simple but effective method to fabricate monolithic LCE actuators that are capable of reversible curvature reversal in bending and twisting deformation by a single stimulus—heat—is reported. The curvature reversal of the LCE film can be programmed by means of asymmetric crosslinking density along the thickness and the orientation of the LC mesogens. The curvature reversal of the monolithic LCE film exhibits highly reversible (more than 100 times) and fast actuation (≈3–5 s) by heating and cooling, allowing new concept of a practical application using LCE material: a self‐regulated smart valve that is capable of qualitatively sorting liquids by temperature. It is believed that this system is potentially applied to a self‐regulated sorting platform for various endothermic and exothermic chemical or biological reactions
A simple triple‐band coupled line filtering power divider design
Authors: Zhang Zhuowei , Zhang Gang , Li Rui , Zhang Simin , Chen Qinzi , Chen Lu , Yang Zhenyuan , Tang Wanchun 
Published: August 2021

AbstractIn this letter, a triple‐band filtering power divider (FPD) is proposed for passive circuit implementation with a good isolation. The proposed triple‐band FPD is composed of coupled microstrip lines by applying a comprehensive design method. Based on the design method and developed topology, the employed coupled microstrip resonators, the input/output feedlines as well as isolated resistor are properly arranged to achieve a desired triple‐band filtering and isolation response. To validate our design concept and method, a triple‐band FPD operating at 2.3–2.33, 2.39–2.42, and 2.5–2.53 GHz is implemented with good return loss and isolation. Measured and simulated results are in good agreement.
Comparison of two versions of a deep learning image reconstruction algorithm on CT image quality and dose reduction: A phantom study
Authors: Greffier Joël , Dabli Djamel , Frandon Julien , Hamard Aymeric , Belaouni Asmaa , Akessoul Philippe , Fuamba Yannick , Le Roy Julien , Guiu Boris , Beregi Jean‐Paul 
Published: August 2021

AbstractPurposeTo compare the impact on CT image quality and dose reduction of two versions of a Deep Learning Image Reconstruction algorithm.Material and methodsAcquisitions on the CT ACR 464 phantom were performed at five dose levels (CTDIvol: 10/7.5/5/2.5/1 mGy) using chest or abdomen pelvis protocol parameters. Raw data were reconstructed using the filtered‐back projection (FBP), the enhanced level of AIDR 3D (AIDR 3De), and the three levels of AiCE (Mild, Standard, and Strong) for the two versions (AiCE V8 vs AiCE V10). The noise power spectrum (NPS) and task‐based transfer function (TTF) for bone (high‐contrast insert) and acrylic (low‐contrast insert) inserts were computed. To quantify the changes of noise magnitude and texture, the square root of the area under the NPS curve and the average spatial frequency (fav) of the NPS curve were measured. The detectability index (d’) was computed to model the detectability of either a large mass in the liver or lung, or a small calcification or high contrast tissue boundaries.ResultsThe noise magnitude was lower with both AiCE versions than with AIDR 3De. The noise magnitude was lower with AiCE V10 than with AiCE V8 (‐4 ± 6% for Mild, ‐13 ± 3% for Standard, and ‐48 ± 0% for Strong levels). fav and TTF50% values for both inserts shifted towards higher frequencies with AiCE than with AIDR 3De. Compared to AiCE V08, fav shifted towards higher frequencies with AiCE V10 (45 ± 4%, 36 ± 3%, and 5 ± 4% for all levels, respectively). The TTF50% values shifted towards higher frequencies with AiCE V10 as compared with AiCE V8 for both inserts, except for the Strong level for the acrylic insert. Whatever the dose and AiCE levels, d’ values were higher with AiCE V10 than with AiCE V8 for the small object/calcification and for the large object/lesion.ConclusionAs compared to AIDR 3De, lower noise magnitude and higher spatial resolution and detectability index were found with both versions of AiCE. As compared to AiCE V8, AiCE V10 reduced noise and improved spatial resolution and detectability without changing the noise texture in a simple geometric phantom, except for the Strong level. AiCE V10 seems to have a greater potential for dose reduction than AiCE V8.
Does the management of personal integrity information lead to differing participation rates and response patterns in mental health surveys with young adults? A three‐armed methodological experiment
Authors: Andersson Claes , Bendtsen Marcus , Lindfors Petra , Molander Olof , Lindner Philip , Topooco Naira , Engström Karin , Berman Anne H. 
Published: August 2021

AbstractObjectivesThis study evaluates whether initiation rates, completion rates, response patterns and prevalence of psychiatric conditions differ by level of personal integrity information given to prospective participants in an online mental health self‐report survey.MethodsA three‐arm, parallel‐group, single‐blind experiment was conducted among students from two Swedish universities. Consenting participants following e‐mail invitation answered the World Health Organization (WHO) World Mental Health‐International College Student (WMH‐ICS) mental health self‐report survey, screening for eight psychiatric conditions. Random allocation meant consenting to respond (1) anonymously; (2) confidentially, or (3) confidentially, where the respondent also gave consent for collection of register data.ResultsNo evidence was found for overall between‐group differences with respect to (1) pressing a hyperlink to the survey in the invitation email; and (2) abandoning the questionnaire before completion. However, participation consent and self‐reported depression were in the direction of higher levels for the anonymous group compared to the two confidential groups.ConclusionsConsent to participate is marginally affected by different levels of personal integrity information. Current standard participant information procedures may not engage participants to read the information thoroughly, and online self‐report mental health surveys may reduce stigma and thus be less subject to social desirability bias.
Free‐breathing multitasking multi‐echo MRI for whole‐liver water‐specific T1, proton density fat fraction, and quantification
Authors: Wang Nan , Cao Tianle , Han Fei , Xie Yibin , Zhong Xiaodong , Ma Sen , Kwan Alan , Fan Zhaoyang , Han Hui , Bi Xiaoming , Noureddin Mazen , Deshpande Vibhas , Christodoulou Anthony G. , Li Debiao 
Published: August 2021

PurposeTo develop a 3D multitasking multi‐echo (MT‐ME) technique for the comprehensive characterization of liver tissues with 5‐min free‐breathing acquisition; whole‐liver coverage; a spatial resolution of 1.5 × 1.5 × 6 mm3; and simultaneous quantification of T1, water‐specific T1 (T1w), proton density fat fraction (PDFF), and .MethodsSix‐echo bipolar spoiled gradient echo readouts following inversion recovery preparation was performed to generate T1, water/fat, and contrast. MR multitasking was used to reconstruct the MT‐ME images with 3 spatial dimensions: 1 T1 recovery dimension, 1 multi‐echo dimension, and 1 respiratory dimension. A basis function–based approach was developed for T1w quantification, followed by the estimation of and T1‐corrected PDFF. The intrasession repeatability and agreement against references of MT‐ME measurements were tested on a phantom and 15 clinically healthy subjects. In addition, 4 patients with confirmed liver diseases were recruited, and the agreement between MT‐ME measurements and references was assessed.ResultsMT‐ME produced high‐quality, coregistered T1, T1w, PDFF, and maps with good intrasession repeatability and substantial agreement with references on phantom and human studies. The intra‐class coefficients of T1, T1w, PDFF, and from the repeat MT‐ME measurements on clinically healthy subjects were 0.989, 0.990, 0.999, and 0.988, respectively. The intra‐class coefficients of T1, PDFF, and between the MT‐ME and reference measurements were 0.924, 0.987, and 0.975 in healthy subjects and 0.980, 0.999, and 0.998 in patients. The T1w was independent to PDFF (R = −0.029, P = .904).ConclusionThe proposed MT‐ME technique quantifies T1, T1w, PDFF, and simultaneously and is clinically promising for the comprehensive characterization of liver tissue properties.
An MR fingerprinting approach for quantitative inhomogeneous magnetization transfer imaging
Authors: West Daniel J. , Cruz Gastao , Teixeira Rui P. A. G. , Schneider Torben , Tournier Jacques‐Donald , Hajnal Joseph V. , Prieto Claudia , Malik Shaihan J. 
Published: August 2021

PurposeMagnetization transfer (MT) and inhomogeneous MT (ihMT) contrasts are used in MRI to provide information about macromolecular tissue content. In particular, MT is sensitive to macromolecules, and ihMT appears to be specific to myelinated tissue. This study proposes a technique to characterize MT and ihMT properties from a single acquisition, producing both semiquantitative contrast ratios and quantitative parameter maps.Theory and MethodsBuilding on previous work that uses multiband RF pulses to efficiently generate ihMT contrast, we propose a cyclic steady‐state approach that cycles between multiband and single‐band pulses to boost the achieved contrast. Resultant time‐variable signals are reminiscent of an MR fingerprinting acquisition, except that the signal fluctuations are entirely mediated by MT effects. A dictionary‐based low‐rank inversion method is used to reconstruct the resulting images and to produce both semiquantitative MT ratio and ihMT ratio maps, as well as quantitative parameter estimates corresponding to an ihMT tissue model.ResultsPhantom and in vivo brain data acquired at 1.5 Tesla demonstrate the expected contrast trends, with ihMT ratio maps showing contrast more specific to white matter, as has been reported by others. Quantitative estimation of semisolid fraction and dipolar T1 was also possible and yielded measurements consistent with literature values in the brain.ConclusionBy cycling between multiband and single‐band pulses, an entirely MT‐mediated fingerprinting method was demonstrated. This proof‐of‐concept approach can be used to generate semiquantitative maps and quantitatively estimate some macromolecular‐specific tissue parameters.
Optimization and variational principles for the shear strength reduction method
Authors: Sysala Stanislav , Hrubešová Eva , Michalec Zdeněk , Tschuchnigg Franz 
Published: August 2021

AbstractIn this paper, a modified shear strength reduction method (MSSR) and its optimization variant (OPT‐MSSR) are suggested. The idea of MSSR is to approximate the standard shear strength reduction to be more stable and rigorous from the numerical point of view. The MSSR method consists of a simplified associated elasto‐plastic model completed by the strength reduction depending on the dilatancy angle. Three Davis' modifications suggested by Tschuchnigg et al. (2015) are interpreted as special cases of MSSR and their factors of safety are compared. The OPT‐MSSR method is derived from MSSR on the basis of rigid plastic assumption, similarly as in limit analysis. Using the variational approach, the duality between the static and kinematic principles of OPT‐MSSR is shown. The numerical solution of OPT‐MSRR is obtained by performing a regularization method in combination with the finite element method, mesh adaptivity and a damped Newton method. In‐house codes (Matlab) are used for the implementation of this solution concept. Finally, two slope stability problems are considered, one of which follows from analysis of a real slope. The softwares packages Plaxis and Comsol Multiphysics are used for comparison of the results.
Stability of electroluminescent perovskite quantum dots light‐emitting diode
Authors: Wen Zhuoqi , Xie Fengxian , Choy Wallace. C. H. 
Published: August 2021

AbstractColloidal quantum dots (QDs) are considered to be a promising candidate for light‐emitting diodes (LEDs) applications considering their wide gamut range, simple color tuning, compatibility with large‐size and flexible substrates. Benefiting from the distinguished properties such as high photoluminescence quantum efficiency (PLQY), narrow emission linewidth, and low material cost, perovskite QDs have attracted wide attention from researchers. Despite tremendous progress has been made during the past several years, perovskite QDs‐based LEDs (QLEDs) are still plagued by the instability arising from the operation of the perovskite QLEDs, which have not been studied systematically. In this review, the origin of the instability of perovskite QLEDs is attributed to the vulnerability of emission materials and constituent layers. Simultaneously, the effective strategies to improve the durability of perovskite QDs and QLEDs are summarized, such as component engineering, ligand passivation, fabrication of robust and uniform constituent layers, as well as adopt appropriate device structures and driving modes. Ultimately, we put forward insights on the future research direction and prospects for perovskite QLEDs in practical applications.
Understanding the influence of anti‐reversion agent and metal oxide dose on natural rubber–carbon black system
Authors: Pal Koushik , Satpathi Hirak , Bhandary Tirthankar , Samui Barun Kumar , Bhattacharyya Sanjay , Naskar Kinsuk , Mukhopadhyay Rabindra 
Published: August 2021

AbstractSulfidic linkages that are formed during the vulcanization process of natural rubber (NR) are unstable at a higher temperature and can be reversed into conjugated diene. To overcome such issue and to build a compound that is hostile to inversion and with increasing service life, anti‐reversion agent (ARA), for example, N,N′‐4,4′‐diphenylmethyene bismaleimide (BMDM), is added into the formulation. This work explains the conjugation reaction mechanism of conjugated diene and BMDM by means of gas chromatography–mass spectrometry and Fourier transform infrared spectroscopy. The first phase of this study is associated with the change in ARA dosage keeping ZnO dosage the same. It is observed that 5 phr of BMDM and 2 phr ZnO combination (ARA4) shows lowest reversion at 160°C. The modulus value at 300% elongation increased 12% by the incorporation of BMDM as compared to the compound of no BMDM (ARA1). The second part is all about keeping BMDM dosage the same at 5 phr level and varying ZnO phr by 3, 4, and 5. From the overall results, it is observed that at a suitable dosage of BMDM and ZnO (5 phr BMDM and 3 phr ZnO combination [ARA5]), least reversion can be achieved and vulcanizates containing optimized BMDM and ZnO show better retention properties after aerobic aging as compared to ARA1.
On the selective killing of cold atmospheric plasma cancer treatment: Status and beyond
Authors: Yan Dayun , Horkowitz Alex , Wang Qihui , Keidar Michael 
Published: August 2021

AbstractCompared with many chemotherapy and radiotherapy modalities, selective killing of cancer cells is a pivotal feature of cold atmospheric plasma (CAP). Understanding its underlying mechanism will build the foundation of CAP‐based cancer treatment. Additionally, we provided forward‐looking thinking to extend the definition of selectivity from conventional cases involving a single‐cell line to a coculture case. Finally, the newly established physically based treatment strategy provides unprecedented visions to realize selectivity beyond the previously established concepts based on reactive species and direct killing effect.
Thermal Decomposition Kinetics of Potential Solid Propellant Combustion Catalysts Fe(II), Zn(II), Hydroxylammonium, and Hydrazinium Pentazolates
Authors: Li Tian‐cheng , Lu Tong‐jie , Lei Qing , Xu Yuan‐gang , Lin Qiu‐han , Lu Ming , Lu Yan‐hua , Wang Peng‐cheng 
Published: August 2021

AbstractHerein, we prepared Fe(II), Zn(II), hydroxylammonium, and hydrazinium pentazolates and investigated their thermal behavior, decomposition kinetics, and thermodynamic activation parameters. The thermolysis of metal and non‐metal salts featured three and two mass‐loss stages, respectively, with the decomposition of pentazolate anions occurring at 105–135 °C. Moreover, metal salts exhibited higher thermal safety than non‐metal salts under the same conditions. Iron and zinc pentazolates decomposed at lower temperatures than sodium pentazolate, i. e., Fe(II) and Zn(II) ions promoted the decomposition of pentazolate anions. The obtained results demonstrate that the prepared compounds hold great promise as energetic catalysts for solid propellant decomposition.