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1.
J Am Chem Soc ; 2024 Jul 17.
Artigo em Inglês | MEDLINE | ID: mdl-39021150

RESUMO

The pursuit of robust, long-range magnetic ordering in two-dimensional (2D) materials holds immense promise for driving technological advances. However, achieving this goal remains a grand challenge due to enhanced quantum and thermal fluctuations as well as chemical instability in the 2D limit. While magnetic ordering has been realized in atomically thin flakes of transition metal chalcogenides and metal halides, these materials often suffer from air instability. In contrast, 2D carbon-based materials are stable enough, yet the challenge lies in creating a high density of local magnetic moments and controlling their long-range magnetic ordering. Here, we report a novel wafer-scale synthesis of an air-stable metallo-carbon nitride monolayer (MCN, denoted as MN4/CNx), featuring ultradense single magnetic atoms and exhibiting robust room-temperature ferromagnetism. Under low-pressure chemical vapor deposition conditions, thermal dehydrogenation and polymerization of metal phthalocyanine (MPc) on copper foil at elevated temperature generate a substantial number of nitrogen coordination sites for anchoring magnetic single atoms in monolayer MN4/CNx (where M = Fe, Co, and Ni). The incorporation of densely populating MN4 sites into monolayer MCN networks leads to robust ferromagnetism up to room temperature, enabling the observation of anomalous Hall effects with excellent chemical stability. Detailed electronic structure calculations indicate that the presence of high-density metal sites results in the emergence of spin-split d-bands near the Fermi level, causing a favorable long-range ferromagnetic exchange coupling through direct exchange interactions. Our work demonstrates a novel synthesis approach for wafer-scale MCN monolayers with robust room-temperature ferromagnetism and may shed light on practical electronic and spintronic applications.

2.
Nat Commun ; 15(1): 5556, 2024 Jul 02.
Artigo em Inglês | MEDLINE | ID: mdl-38956033

RESUMO

Chiral multiferroics offer remarkable capabilities for controlling quantum devices at multiple levels. However, these materials are rare due to the competing requirements of long-range orders and strict symmetry constraints. In this study, we present experimental evidence that the coexistence of ferroelectric, magnetic orders, and crystallographic chirality is achievable in hybrid organic-inorganic perovskites [(R/S)-ß-methylphenethylamine]2CuCl4. By employing Landau symmetry mode analysis, we investigate the interplay between chirality and ferroic orders and propose a novel mechanism for chirality transfer in hybrid systems. This mechanism involves the coupling of non-chiral distortions, characterized by defining a pseudo-scalar quantity, ξ = p ⋅ r ( p represents the ferroelectric displacement vector and r denotes the ferro-rotational vector), which distinguishes between (R)- and (S)-chirality based on its sign. Moreover, the reversal of this descriptor's sign can be associated with coordinated transitions in ferroelectric distortions, Jahn-Teller antiferro-distortions, and Dzyaloshinskii-Moriya vectors, indicating the mediating role of crystallographic chirality in magnetoelectric correlations.

3.
Acta Psychol (Amst) ; 248: 104363, 2024 Jun 20.
Artigo em Inglês | MEDLINE | ID: mdl-38905953

RESUMO

Engaging in chasing, where an actor actively pursues a target, is considered a crucial activity for the development of social skills. Previous studies have focused predominantly on understanding the neural correlates of chasing from an observer's perspective, but the neural mechanisms underlying the real-time implementation of chasing action remain poorly understood. To gain deeper insights into this phenomenon, the current study employed functional near-infrared spectroscopy (fNIRS) techniques and a novel interactive game. In this interactive game, participants (N = 29) were tasked to engage in chasing behavior by controlling an on-screen character using a gamepad, with the goal of catching a virtual partner. To specifically examine the brain activations associated with the interactive nature of chasing, we included two additional interactive actions: following action of following the path of a virtual partner and free action of moving without a specific pursuit goal. The results revealed that chasing and following actions elicited activation in a broad and overlapping network of brain regions, including the temporoparietal junction (TPJ), medial prefrontal cortex (mPFC), premotor cortex (PMC), primary somatosensory cortex (SI), and primary motor cortex (M1). Crucially, these regions were found to be modulated by the type of interaction, with greater activation and functional connectivity during the chasing interaction than during the following and free interactions. These findings suggested that both the MNS, encompassing regions such as the PMC, M1 and SI, and the mentalizing system (MS), involving the TPJ and mPFC, contribute to the execution of online chasing actions. Thus, the present study represents an initial step toward future investigations into the roles of MNS and MS in real-time chasing interactions.

4.
Behav Sci (Basel) ; 14(6)2024 May 31.
Artigo em Inglês | MEDLINE | ID: mdl-38920802

RESUMO

The aim of this study was to investigate the impact of extended bridge expertise on rapid perceptual processing and brain functional plasticity in early adulthood, utilizing functional magnetic resonance imaging (fMRI). In this investigation, we compared 6 high-level college bridge players with 25 college students lacking bridge experience, assessing their intelligence and working memory. Additionally, we scrutinized behavioral performance and whole-brain activation patterns during an image perceptual judgment task. Findings indicated significant group and interaction effects at the behavioral level. Bridge players exhibited prolonged reaction times and enhanced accuracy on card tasks. At the neural level, the activation level of bridge players in the occipital lobe exceeded that of ordinary college students, with more pronounced group effects in the motor area and inferior parietal lobule during card tasks. This implies that bridge expertise in early adulthood induces functional plasticity changes in regions associated with visual processing and automated mathematical computation.

5.
Behav Sci (Basel) ; 14(4)2024 Mar 27.
Artigo em Inglês | MEDLINE | ID: mdl-38667074

RESUMO

The belief in online news has become a topical issue. Previous studies demonstrated the role emotion plays in fake news vulnerability. However, few studies have explored the effect of empathy on online news belief. This study investigated the relationship between trait empathy, state empathy, belief in online news, and the potential moderating effect of news type. One hundred and forty undergraduates evaluated 50 online news pieces (25 real, 25 fake) regarding their belief, state empathy, valence, arousal, and familiarity. Trait empathy data were collected using the Chinese version of the Interpersonal Reactivity Index. State empathy was positively correlated with affective empathy in trait empathy and believability, and affective empathy was positively correlated with believability. The influence of affective empathy on news belief was partially mediated by state empathy and regulated by news type (fake, real). We discuss the influence of empathy on online news belief and its internal processes. This study shares some unique insights for researchers, practitioners, social media users, and social media platform providers.

6.
BMC Nurs ; 23(1): 172, 2024 Mar 14.
Artigo em Inglês | MEDLINE | ID: mdl-38481274

RESUMO

BACKGROUND: The quality of transitional care is closely related to the health outcomes of patients, and understanding the status of transitional care for patients is crucial to improving the health outcomes of patients. Therefore, this study aims to investigate the quality of transitional care in elderly patients with chronic diseases and analyze its influencing factors, to provide a basis for improving transitional care services. METHODS: This is a cross-sectional study. We used the Chinese version of the Partners at Care Transitions Measure (PACT-M) to survey patients with chronic diseases aged 60 years and older who were about to be discharged from five tertiary hospitals in Henan and Shanxi provinces. We used the mean ± standard deviation to describe the quality of transitional care, t-test or one-way ANOVA, and regression analysis to explore the factors affecting the quality of transitional care for patients. RESULTS: 182 elderly patients with chronic diseases aged ≥ 60 years completed the PACT-M survey. The scores of PACT-M1 and PACT-M2 were (30.69 ± 7.87) and (25.59 ± 7.14) points, respectively. The results of the t-test or one-way ANOVA showed that the patient's marital status, ethnicity, religion, educational level, preretirement occupation, residence, household income per month, and living situation had an impact on the quality of transitional care for elderly patients with chronic diseases (P < 0.05). The results of regression analyses showed that patients' preretirement occupation, social support, and health status were the main influences on the quality of transitional care for elderly patients with chronic diseases (P < 0.05), and they explained 63.1% of the total variance. CONCLUSIONS: The quality of transitional care for older patients with chronic illnesses during the transition from hospital to home needs further improvement. Factors affecting the quality of transitional care included patients' pre-retirement occupation, social support, and health status. We can improve the hospital-community-family tertiary linkage service to provide coordinated and continuous transitional care for patients based on their occupation, health status, and social support to enhance the quality of transitional care and the patient's health.

7.
Cereb Cortex ; 34(3)2024 03 01.
Artigo em Inglês | MEDLINE | ID: mdl-38494416

RESUMO

Previous research has confirmed significant differences in regional brain activity and functional connectivity between endurance athletes and non-athletes. However, no studies have investigated the differences in topological efficiency of the brain functional network between endurance athletes and non-athletes. Here, we compared differences in regional activities, functional connectivity, and topological properties to explore the functional basis associated with endurance training. The results showed significant correlations between Regional Homogeneity in the motor cortex, visual cortex, cerebellum, and the training intensity parameters. Alterations in functional connectivity among the motor cortex, visual cortex, cerebellum, and the inferior frontal gyrus and cingulate gyrus were significantly correlated with training intensity parameters. In addition, the graph theoretical analysis results revealed a significant reduction in global efficiency among athletes. This decline is mainly caused by decreased nodal efficiency and nodal local efficiency of the cerebellar regions. Notably, the sensorimotor regions, such as the precentral gyrus and supplementary motor areas, still exhibit increased nodal efficiency and nodal local efficiency. This study not only confirms the improvement of regional activity in brain regions related to endurance training, but also offers novel insights into the mechanisms through which endurance athletes undergo changes in the topological efficiency of the brain functional network.


Assuntos
Encéfalo , Imageamento por Ressonância Magnética , Humanos , Imageamento por Ressonância Magnética/métodos , Encéfalo/diagnóstico por imagem , Mapeamento Encefálico/métodos , Giro do Cíngulo , Atletas
8.
CNS Neurosci Ther ; 30(3): e14662, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38477221

RESUMO

BACKGROUND: Intermittent hypoxia (IH) is emerging as a cost-effective nonpharmacological method for vital organ protection. We aimed to assess the effects of a short-term moderate intermittent hypoxia preconditioning protocol (four cycles of 13% hypoxia lasting for 10 min with 5-min normoxia intervals) on acute hypoxic injury induced by sustained hypoxic exposure (oxygen concentration of 11.8% for 6 h). METHODS: One hundred healthy volunteers were recruited and randomized to the IH group and the control group to receive IH or sham-IH preconditioning for 5 days, respectively, and then were sent to a hypoxic chamber for simulated acute high-altitude exposure (4500 m). RESULTS: The overall incidence of acute mountain sickness was 27% (27/100), with 14% (7/50) in the IH group and 40% (20/50) in the control group (p = 0.003). After 6-h simulated high-altitude exposure, the mean Lake Louise Score was lower in the IH group as compared to controls (1.30 ± 1.27 vs. 2.04 ± 1.89, p = 0.024). Mean peripheral oxygen saturations (SpO2 ) and intracranial pressure (ICP) measures after acute hypoxic exposure exhibited significant differences, with the IH group showing significantly greater SpO2 values (85.47 ± 5.14 vs. 83.10 ± 5.15%, p = 0.026) and lower ICP levels than the control group (115.59 ± 32.15 vs. 130.36 ± 33.83 mmH2 O, p = 0.028). IH preconditioning also showed greater effects on serum protein gene product 9.5 (3.89 vs. 29.16 pg/mL; p = 0.048) and C-reactive protein (-0.28 vs. 0.41 mg/L; p = 0.023). CONCLUSION: The short-term moderate IH improved the tolerance to hypoxia and exerted protection against acute hypoxic injury induced by exposure to sustained normobaric hypoxia, which provided a novel method and randomized controlled trial evidence to develop treatments for hypoxia-related disease.


Assuntos
Doença da Altitude , Hipóxia , Humanos , Hipóxia/metabolismo , Doença da Altitude/metabolismo , Doença da Altitude/prevenção & controle , Doença Aguda , Condicionamento Psicológico , Oxigênio
9.
Opt Express ; 32(3): 3793-3803, 2024 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-38297592

RESUMO

In this paper, we introduce a novel approach for detecting Denial of Service (DoS) attacks in software-defined IP over optical networks, leveraging machine learning to analyze optical spectrum features. This method employs machine learning to automatically process optical spectrum data, which is indicative of network security status, thereby identifying potential DoS attacks. To validate its effectiveness, we conducted both numerical simulations and experimental trials to collect relevant optical spectrum datasets. We then assessed the performance of three machine learning algorithms XGBoost, LightGBM, and the BP neural network in detecting DoS attacks. Our findings show that all three algorithms demonstrate a detection accuracy exceeding 97%, with the BP neural network achieving the highest accuracy rates of 99.55% and 99.74% in simulations and experiments, respectively. This research not only offers a new avenue for DoS attack detection but also enhances early detection capabilities in the underlying optical network through optical spectrum data analysis.

10.
Opt Express ; 32(2): 1736-1755, 2024 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-38297719

RESUMO

In the fifth generation fixed networks (F5G) era, full-fiber-connected optical networks support emerging bandwidth-hungry services. However, optical networks are vulnerable to attack by tapping or other methods, which has been paid more and more attention in modern optical infrastructure. Therefore, high-speed optoelectronic firewalls appear as one of the promising technologies to guarantee security. The most significant and challenging component of a high-speed optoelectronic firewall is all-optical pattern recognition, especially for more advanced high-order modulation formats such as phase shift keying (PSK) or quadrature amplitude modulation (QAM) to satisfy efficient enhanced fixed broadband in F5G. In this paper, what we believe to be a novel reconfigurable all-optical pattern recognition system for PSK and QAM signals is proposed with two implementation architectures. The proposed system mainly consists of a generalized XNOR (GXNOR) and a recirculating loop. The two implementation architectures are precisely two realization methods of the GXNOR part. One employs two cascaded IQ Mach-Zehnder modulators and the other is implemented by the four-wave mixing. The numerical simulation results demonstrate that the two implementation architectures can both achieve all-optical pattern recognition for the reconfigurable high-order modulation formats of QPSK, 8PSK, and 16QAM with the recorded baud rate of 260GBaud.

11.
Nat Commun ; 15(1): 1383, 2024 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-38360821

RESUMO

Cobalt oxyhydroxide (CoOOH) is a promising catalytic material for oxygen evolution reaction (OER). In the traditional CoOOH structure, Co3+ exhibits a low-spin state configuration ([Formula: see text]), with electron transfer occurring in face-to-face [Formula: see text] orbitals. In this work, we report the successful synthesis of high-spin state Co3+ CoOOH structure, by introducing coordinatively unsaturated Co atoms. As compared to the low-spin state CoOOH, electron transfer in the high-spin state CoOOH occurs in apex-to-apex [Formula: see text] orbitals, which exhibits faster electron transfer ability. As a result, the high-spin state CoOOH performs superior OER activity with an overpotential of 226 mV at 10 mA cm-2, which is 148 mV lower than that of the low-spin state CoOOH. This work emphasizes the effect of the spin state of Co3+ on OER activity of CoOOH based electrocatalysts for water splitting, and thus provides a new strategy for designing highly efficient electrocatalysts.

12.
Small Methods ; : e2301219, 2024 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-38180156

RESUMO

Single-atom catalysts (SACs) have made great progress in recent years as potential catalysts for energy conversion and storage due to their unique properties, including maximum metal atoms utilization, high-quality activity, unique defined active sites, and sustained stability. Such advantages of single-atom catalysts significantly broaden their applications in various energy-conversion reactions. Given the extensive utilization of single-atom catalysts, methods and specific examples for improving the performance of single-atom catalysts in different reaction systems based on the Sabatier principle are highlighted and reactant binding energy volcano relationship curves are derived in non-homogeneous catalytic systems. The challenges and opportunities for single-atom catalysts in different reaction systems to improve their performance are also focused upon, including metal selection, coordination environments, and interaction with carriers. Finally, it is expected that this work may provide guidance for the design of high-performance single-atom catalysts in different reaction systems and thereby accelerate the rapid development of the targeted reaction.

13.
Nano Lett ; 24(2): 733-740, 2024 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-38166427

RESUMO

The Hall effect has played a vital role in unraveling the intricate properties of electron transport in solid materials. Here, we report on a crystal symmetry-dependent in-plane Hall effect (CIHE) observed in a CuPt/CoPt ferromagnetic heterostructure. Unlike the planar Hall effect (PHE), the CIHE in CuPt/CoPt strongly depends on the current flowing direction (ϕI) with respect to the crystal structure. It reaches its maximum when the current is applied along the low crystal-symmetry axes and vanishes when applied along the high crystal-symmetry axes, exhibiting an unconventional angular dependence of cos(3ϕI). Utilizing a symmetry analysis based on the Invariant Theory, we demonstrate that the CIHE can exist in magnetic crystals possessing C3v symmetry. Using a tight-binding model and realistic first-principles calculations on the metallic heterostructure, we find that the CIHE originates from the trigonal warping of the Fermi surface. Our observations highlight the critical role of crystal symmetry in generating new types of Hall effects.

14.
Nat Commun ; 15(1): 745, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38272914

RESUMO

The electrical control of the non-trivial topology in Weyl antiferromagnets is of great interest for the development of next-generation spintronic devices. Recent studies suggest that the spin Hall effect can switch the topological antiferromagnetic order. However, the switching efficiency remains relatively low. Here, we demonstrate the effective manipulation of antiferromagnetic order in the Weyl semimetal Mn3Sn using orbital torques originating from either metal Mn or oxide CuOx. Although Mn3Sn can convert orbital current to spin current on its own, we find that inserting a heavy metal layer, such as Pt, of appropriate thickness can effectively reduce the critical switching current density by one order of magnitude. In addition, we show that the memristor-like switching behaviour of Mn3Sn can mimic the potentiation and depression processes of a synapse with high linearity-which may be beneficial for constructing accurate artificial neural networks. Our work paves a way for manipulating the topological antiferromagnetic order and may inspire more high-performance antiferromagnetic functional devices.

15.
PeerJ ; 12: e16764, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38225929

RESUMO

Background: Sensorimotor communication is frequently observed in complex joint actions and social interactions. However, it remains challenging to explore the cognitive foundations behind sensorimotor communication. Methods: The present study extends previous research by introducing a single-person baseline condition and formulates two distinct categories of asymmetric joint action tasks: distance tasks and orientation tasks. This research investigates the action performance of 65 participants under various experimental conditions utilizing a 2 (cooperative intention: Coop, No-coop) × 2 (task characteristic: distance, orientation) × 4 (target: T1, T2, T3, T4) repeated-measures experimental design to investigate the cognitive mechanisms underlying sensorimotor communication between individuals. Results: The results showed that (1) target key dwell time, motion time, total motion time, and maximum motion height in the Coop condition are more than in the No-coop condition. (2) In the distance task without cooperative intention, the dwell time of T4 is smaller than T1, T2, T3, and its variability of T1, T2, T3, and T4 were no different. In the distance task with cooperative intention, the dwell time and its variability of T1, T2, T3, and T4 displayed an increasing trend. (3) In the orientation task without cooperative intention, the dwell time of T1 is smaller than T2, T3, T4, and variability of the target keys T1, T2, T3, and T4 had no difference. In the orientation task with cooperative intention, the dwell time and variability of the target keys T1, T2, T3, and T4 had increasing trends. Conclusions: Those findings underscore the importance of cooperative intention for sensorimotor communication. In the distance task with cooperative intention, message senders establish a mapping relationship characterized by "near-small, far-large" between the task distance and the individual's action characteristics through sensorimotor experience. In the orientation task with cooperative intention, message senders combined sensorimotor experience and verbal metaphors to establish a mapping relationship between task orientation and action characteristics, following the sequence of "left-up, right-up, left-down, right-down" to transmit the message to others.

16.
ACS Appl Mater Interfaces ; 16(1): 1129-1136, 2024 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-38118124

RESUMO

Materials with strong spin-orbit coupling (SOC) have been continuously attracting intensive attention due to their promising application in energy-efficient, high-density, and nonvolatile spintronic devices. Particularly, transition-metal perovskite oxides with strong SOC have been demonstrated to exhibit efficient charge-spin interconversion. In this study, we systematically investigated the impact of epitaxial strain on the spin-orbit torque (SOT) efficiency in the SrIrO3(SIO)/Ni81Fe19(Py) bilayer. The results reveal that the SOT efficiency is strongly related to the octahedral rotation around the in-plane axes of the single-crystal SIO. By modulating the epitaxial strain using different substrates, the SOT efficiency can be remarkably improved from 0.15 to 1.45. This 10-fold enhancement of SOT efficiency suggests that modulating the epitaxial strain is an efficient approach to control the SOT efficiency in complex oxide-based heterostructures. Our work may have the potential to advance the application of complex oxides in energy-efficient spintronic devices.

17.
Int J Med Sci ; 20(12): 1551-1561, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37859700

RESUMO

Severe hypoxia can induce a range of systemic disorders; however, surprising resilience can be obtained through sublethal adaptation to hypoxia, a process termed as hypoxic conditioning. A particular form of this strategy, known as intermittent hypoxia conditioning hormesis, alternates exposure to hypoxic and normoxic conditions, facilitating adaptation to reduced oxygen availability. This technique, originally employed in sports and high-altitude medicine, has shown promise in multiple pathologies when applied with calibrated mild to moderate hypoxia and appropriate hypoxic cycles. Recent studies have extensively investigated the protective role of intermittent hypoxia conditioning and its underlying mechanisms using animal models, demonstrating its potential in organ protection. This involves a range of processes such as reduction of oxidative stress, inflammation, and apoptosis, along with enhancement of hypoxic gene expression, among others. Given that intermittent hypoxia conditioning fosters beneficial physiological responses across multiple organs and systems, this review presents a comprehensive analysis of existing studies on intermittent hypoxia and its potential advantages in various organs. It aims to draw attention to the possibility of clinically applying intermittent hypoxia conditioning as a multi-organ protective strategy. This review comprehensively discusses the protective effects of intermittent hypoxia across multiple systems, outlines potential procedures for implementing intermittent hypoxia, and provides a brief overview of the potential protective mechanisms of intermittent hypoxia.


Assuntos
Hipóxia , Oxigênio , Animais , Hipóxia/terapia , Hipóxia/metabolismo , Estresse Oxidativo
18.
Nat Commun ; 14(1): 6160, 2023 10 03.
Artigo em Inglês | MEDLINE | ID: mdl-37789028

RESUMO

Chronic stress is a known risk factor for breast cancer, yet the underlying mechanisms are unclear. This study explores the potential involvement of microbial and metabolic signals in chronic stress-promoted breast cancer progression, revealing that reduced abundances of Blautia and its metabolite acetate may contribute to this process. Treatment with Blautia and acetate increases antitumor responses of CD8+ T cells and reverses stress-promoted breast cancer progression in female mice. Patients with depression exhibit lower abundances of Blautia and acetate, and breast cancer female patients with depression display lower abundances of acetate, decreased numbers of tumor-infiltrating CD8+ T cells, and an increased risk of metastasis. These results suggest that Blautia-derived acetate plays a crucial role in modulating the immune response to breast cancer, and its reduction may contribute to chronic stress-promoted cancer progression. Our findings advance the understanding of microbial and metabolic signals implicated in cancer in patients with depression and may provide therapeutic options for female patients with breast cancer and depression.


Assuntos
Neoplasias da Mama , Feminino , Humanos , Camundongos , Animais , Neoplasias da Mama/metabolismo , Linfócitos T CD8-Positivos
19.
J Am Chem Soc ; 145(33): 18549-18559, 2023 Aug 23.
Artigo em Inglês | MEDLINE | ID: mdl-37579341

RESUMO

Organic-inorganic metal hybrids with their tailorable lattice dimensionality and intrinsic spin-splitting properties are interesting material platforms for spintronic applications. While the spin decoherence process is extensively studied in lead- and tin-based hybrids, these systems generally show short spin decoherence lifetimes, and their correlation with the lattice framework is still not well-understood. Herein, we synthesized magnetic manganese hybrid single crystals of (4-fluorobenzylamine)2MnCl4, ((R)-3-fluoropyrrolidinium)MnCl3, and (pyrrolidinium)2MnCl4, which represent a change in lattice dimensionality from 2D and 1D to 0D, and studied their spin decoherence processes using continuous-wave electron spin resonance spectroscopy. All manganese hybrids exhibit nanosecond-scale spin decoherence time τ2 dominated by the symmetry-directed spin exchange interaction strengths of Mn2+-Mn2+ pairs, which is much longer than lead- and tin-based metal hybrids. In contrast to the similar temperature variation laws of τ2 in 2D and 0D structures, which first increase and gradually drop afterward, the 1D structure presents a monotonous rise of τ2 with the temperatures, indicating the strong correlation of spin decoherence with the lattice rigidity of the inorganic framework. This is also rationalized on the basis that the spin decoherence is governed by the competitive contributions from motional narrowing (prolonging the τ2) and electron-phonon coupling interaction (shortening the τ2), both of which are thermally activated, with the difference that the former is more pronounced in rigid crystalline lattices.

20.
Opt Express ; 31(14): 22802-22816, 2023 Jul 03.
Artigo em Inglês | MEDLINE | ID: mdl-37475383

RESUMO

Extensive investigations are undertaken on the feasibility of utilizing phase sensitive amplification (PSA) in highly nonlinear fiber (HNLF) to achieve a reconfigurable 16QAM/8QAM all-optical format conversion for optical data center networks. A comprehensive theoretical model is developed and subsequently verified, based on numerical simulations undertaken to explore the effectiveness of the nonlinear effects of phase insensitive amplification, PSA, and self phase modulation for the proposed all-optical format conversion scheme. It is demonstrated that the proposed scheme can achieve a reconfigurable all-optical format conversion from a 16QAM signal to two quadrature phase shift keying (QPSK) signals or from an 8QAM signal to one QPSK signal and one binary phase shift keying signal with data rates of 92Gbps and 69Gbps for 16QAM and 8QAM signals, respectively.

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