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1.
J Nurs Manag ; 30(6): 1590-1599, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-34699090

RESUMO

AIMS: This study aimed to analyse the prevalence of nurse-to-nurse horizontal violence in Chinese hospitals and examine the effects of head nurse's caring and nurse's group behaviour on horizontal violence. BACKGROUND: Horizontal violence is a serious global problem affecting the nursing profession, but little is known of the issue in Chinese hospitals. Increasing evidence has showed that leadership and group factors are important in facilitating horizontal violence. Whether the head nurse's caring and group behaviour perceived by nurses has protective effects against horizontal violence remains unclear. METHODS: A cross-sectional online-based questionnaire study was performed in seven general hospitals in Hubei Province, China. Data related to the demographic information, horizontal violence, head nurse's caring and group behaviour were collected. Descriptive analyses, chi-squared tests and logistic regression were used for data analysis. RESULTS: In total, 1942 valid questionnaires were collected, with a 92.70% effective response rate (1942/2095). Of those, 59.1% (1148/1942) of respondents had experienced horizontal violence at least once in the previous 6 months. Covert negative behaviours were more frequently reported. Compared with the low level, moderate and high levels of the head nurse's caring showed a lower risk of horizontal violence (odds ratio [OR] = 0.400, p < .001; OR = 0.128, p < .001); moderate and high levels of group behaviour also showed a reduced risk (OR = 0.601, p < .001; OR = 0.221, p < .001). CONCLUSION: Horizontal violence is common among Chinese nurses. The head nurse's caring and maintaining a good climate of nurses' group behaviours could serve as protective factors for preventing horizontal violence. IMPLICATIONS FOR NURSING MANAGEMENT: This study helps nursing managers identify which specific negative behaviours occur frequently and require special attention. It suggests that nursing managers attach importance to improving their caring ability towards nurses and to creating an amicable climate of group behaviour to buffer against horizontal violence.


Assuntos
Enfermeiros Administradores , Recursos Humanos de Enfermagem Hospitalar , Estudos Transversais , Hospitais , Humanos , Eventos de Massa , Papel do Profissional de Enfermagem , Supervisão de Enfermagem , Inquéritos e Questionários , Violência/prevenção & controle
2.
Opt Express ; 29(23): 38557-38566, 2021 Nov 08.
Artigo em Inglês | MEDLINE | ID: mdl-34808906

RESUMO

Heat-sensitive materials have great applications in sensor, detector, and tunable photoelectric devices. However, the wave-thermal effect of the heat-sensitive material is rarely been investigated in the THz range. Here, we propose the incorporation of heat-sensitive material (strontium titanate (STO)) within a THz absorber. The simulated results show that the absorptance and frequency can be dynamically controlled by the temperature of STO. Because the absorbed THz waves are finally converted into heat, then we research the theoretical mechanism of heat generation. Theoretical analysis shows that there are two reasons for the temperature rise: surface plasmon polariton (SPP) and ohmic loss of gold patch; Electromagnetic energy consumption inside the loss materials. To verify the theory, finally, we use COMSOL Multiphysics to research the nanosecond wave-thermal effect. The transient temperature of the wave-thermal effect is calculated quantitatively. The quantitative prediction of temperature variation can provide good guidance for thermal regulation and wave-thermally tunable THz devices.

3.
Opt Express ; 28(4): 5306-5316, 2020 Feb 17.
Artigo em Inglês | MEDLINE | ID: mdl-32121754

RESUMO

We present a saline water-based absorber that can offer an extremely wide bandwidth of electromagnetic absorption in the microwave frequency regime. The designed absorber is a hybrid of saline water and Poly Tetra Fluoro Ethylene (PTFE) dielectric material, which exhibits an absorption level greater than 90% across the frequency band from 1.4 to 3.3 and 4.3 to 63 GHz, with a relative absorption bandwidth as high as 180%. Meanwhile, the sensitivity of the absorption against oblique incidence is studied for both TE and TM polarizations. Additionally, the absorption performance of this saline water-based absorber could be tunable by changing the salinity and the combination of different temperatures and salinity. To explain the mechanism, interference theory is employed to investigate the designed absorber, and the theoretically calculated results are well in agreement with the simulation. This design offers an effective and feasible way to construct tunable and ultra-broadband absorber in low-cost stealth technology.

4.
Opt Express ; 28(10): 15744-15752, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32403595

RESUMO

We proposed a polarization-insensitive absorber based on strontium titanate (STO) and bulk Dirac semimetal (BDS) in the terahertz (THz) region. The center frequency of the absorption peak can be independently regulated by temperature or Fermi energy level of STO or BDS, respectively. The numerical simulation result reveals that the peak absorptivity reaches to 99.98% at 2.16 THz when the temperature and Fermi energy were set at 300 K and 20 meV, respectively. Interestingly, by adjusting the temperature of STO from 250 to 400 K, the simulation results indicate that the center frequency can be tuned from 1.94 to 2.53 THz, and peak absorptivity can be maintained above 99% at normal incident. As the Fermi energy EF of Dirac semimetal increases from 10 to 60 meV, the center frequency can be changed from 2.14 to 2.44 THz and the amplitude of absorption peaks can be tuned from 99.9% to 82.8%. Impedance matching theory was used to understand the tunable performance. Furthermore, interference theory was employed to further explain the absorption mechanism of the proposed absorber. The absorber achieves bi-controlled absorptance via two independently controllable methods, which may provide guidance to research tunable, smart and multifunctional terahertz devices.

5.
Opt Express ; 28(9): 13884-13894, 2020 Apr 27.
Artigo em Inglês | MEDLINE | ID: mdl-32403854

RESUMO

We proposed a dual-controlled broadband terahertz (THz) absorber based on graphene and Dirac semimetal. Calculated results show that the absorptance over 90% is achieved in the frequency range of 4.79-8.99 THz for both transverse electric (TE) and transverse magnetic (TM) polarizations. Benefiting from the advantage of the dielectric constant of these materials varying with chemical doping or gate voltage, the simulation results exhibit that the absorbance bandwidth can be controlled independently or jointly by varying the Fermi energy of the graphene or Dirac semimetal patterns instead of redesigning the absorbers. Impedance matching theory was introduced to analyze the absorption spectra changing with EF. The bandwidth and absorptivity of the proposed absorber are almost independent of changing the incident angle θ up to 35° and 40° for TE and TM modes, respectively. It works well even at a larger incident angle. Because of the symmetry of the structure, this designed absorber is polarization insensitive and almost the same absorptivity for both polarizations. Furthermore, the physical mechanisms were further disclosed by the electric field distributions. The proposed broadband and dual-controlled absorber may have potential applications in various fields of high-performance terahertz devices.

6.
Appl Opt ; 59(16): 4970-4976, 2020 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-32543494

RESUMO

In this paper, we propose a broadband tunable metamaterial absorber in the terahertz (THz) region. The absorber comprises a Dirac semimetal film, a dielectric layer, and a gold ground plane. Numerical results show that the absorptivity remains above 90% in the range from 5.7 THz to 8.4 THz when the Fermi level is 65 meV. By varying the Fermi energy of the Dirac semimetal film from 40 meV to 80 meV, the absorption bandwidth and absorption peaks can be dynamically tuned. To explain the mechanism of high absorption, the magnetic field, surface current, and power loss density distributions at different resonant frequencies were presented. Our work may have potential applications in various fields such as sensors, detectors, and photovoltaic devices in THz regions.

7.
Appl Opt ; 59(23): 7092-7098, 2020 Aug 10.
Artigo em Inglês | MEDLINE | ID: mdl-32788804

RESUMO

IWe have designed, simulated, and experimentally tested a broadband metamaterial absorber loaded with lumped resistors in the microwave range. Compared with an electric resonator structure absorber, the composite absorber loaded with lumped resistors has stronger absorptivity over an extremely extended bandwidth. The simulated results show that an effective absorption bandwidth covers from 7.12 to 8.61 GHz with the absorption rate more than 90% under normal incidence. For oblique incidence, the proposed absorber displays an absorption rate above 90% from 7.55 to 8.61 GHz when the incident angle is below 35° for the transverse electric polarization. About the transverse magnetic polarization, the absorber displays larger than 90% absorptance from 7.24 to 8.61 GHz when the incident angle is below 70°. During the entire design process, the absorber structure is fabricated and measured. The measured results show that the absorptivity is above 90% in the frequency range of 6.78-7.65 GHz and 8.20-9.31 GHz under normal incidence. Furthermore, the absorption mechanism and absorption properties are further researched.

8.
Opt Express ; 27(15): 20734-20744, 2019 Jul 22.
Artigo em Inglês | MEDLINE | ID: mdl-31510162

RESUMO

Aiming to achieve simultaneous measurement of airflow speed and direction with high accuracy, a new all-optical airflow sensor based on triangulation concept is proposed. It consists of a suspending tapered fiber tip and a multicore fiber, acting as the flow interaction element and the localization reference, respectively. During operation, the detection light emitted from the tapered fiber will be coupled to the multicore fiber. Upon exposure to airflow, the induced deflection of the tapered fiber tip will change the individual receiving optical powers of the three cores arranged into triangular pattern, which are dependent on both of the flow speed and direction. Through properly designing structure parameters as core spacing, suspending length, tip diameter and axial fiber distance, the omnidirectional airflow with flow speed within 90 mm/s has been experimentally measured with high fidelity.

9.
BMC Plant Biol ; 18(1): 87, 2018 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-29764367

RESUMO

BACKGROUND: Papain-like and legumain-like proteases are proteolytic enzymes which play key roles in plant development, senescence and defense. The activities of proteases in both families could be inhibited by a group of small proteins called cystatin. Cystatin family genes have been well characterized both in tobacco and rice, suggesting their potential roles in seed development. However, their potential targets, papain-like and legumain-like proteases, have not been well characterized in plants, especially in rice, a model plant for cereal biology. RESULTS: Here, 33 papain-like and 5 legumain-like proteases have been identified in rice genome, respectively. Gene structure, distribution in rice chromosome, and evolutionary relationship to their counterparts in other plants have been well characterized. Comprehensive expression profile analysis revealed that two family genes display divergent expression pattern, which are regulated temporally and spatially during the process of seed development and germination. Our experiments also revealed that the expression of most genes in these two families is sensitively responsive to plant hormones and different abiotic stresses. CONCLUSIONS: Genome-wide identification and comprehensive gene expression pattern analysis of papain-like and legumain-like proteases in rice suggests their multiple and cooperative roles in seed development and response to environmental variations, which provides several useful cues for further in-depth study.


Assuntos
Cisteína Endopeptidases/genética , Genes de Plantas/genética , Oryza/enzimologia , Papaína/genética , Peptídeo Hidrolases/genética , Proteínas de Plantas/genética , Mapeamento Cromossômico , Cromossomos de Plantas/genética , Cisteína Endopeptidases/metabolismo , Perfilação da Expressão Gênica , Genes de Plantas/fisiologia , Estudo de Associação Genômica Ampla , Oryza/genética , Papaína/metabolismo , Peptídeo Hidrolases/metabolismo , Filogenia , Proteínas de Plantas/metabolismo , Alinhamento de Sequência
10.
Opt Express ; 26(2): 1681-1688, 2018 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-29402039

RESUMO

A broadband tunable metamaterial graphene absorber is investigated in this paper. The unit cell of the proposed metamaterial graphene absorber is composed of four patch resonators. By tuning the chemical potential of graphene and the geometric size of each patch, the simulated total reflectivity is less than -10 dB from 22.02 to 36.61 THz and with the total thickness of 0.76 um (only 0.09λ at the lowest frequency). The analysis of the surface current, magnetic field and power flow distributions has been performed to better understand the absorption mechanism. Moreover, this proposed absorber achieves its bandwidth tunable characteristics through a voltage biasing of the graphene's Fremi level. This proposed metamaterial graphene absorber (MGA) could be used as smart absorbers, photovoltaic devices and tunable sensors.

11.
Opt Lett ; 42(22): 4593-4595, 2017 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-29140320

RESUMO

Aiming for a three-lens slit spatial filtering system with excellent performances in inhibition of pinhole closure, improvement of beam quality, compactness of the system, and lowering the requirement of vacuum, the filtering characteristics and image relay of the slit spatial filter are demonstrated. The results show that the beam quality is greatly improved, and the system has a good property in image relay, which has potential applications in high-power lasers.

12.
Clin Exp Pharmacol Physiol ; 44(8): 895-902, 2017 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-28477368

RESUMO

Recently, numerous studies have revealed that long non-coding RNAs (lncRNAs) play complex roles in various lung diseases, while the colorectal neoplasia differentially expressed (CRNDE) functions in non-small cell lung carcinomas (NSCLC) remain largely unknown. In the present study, we investigate the role and mechanism of CRNDE in the progression of NSCLC. The mRNA level of CRNDE in NSCLC patients and cells was detected by qRT-PCR. The influence of CRNDE silencing or over-expression on NSCLC cell proliferation and growth were assessed by MTT and flow cytometry, respectively. We also investigated the effect of abnormal CRNDE expression on cyclins and PI3K/AKT pathway. Furthermore, si-CRNDE NSCLC cell lines were injected subcutaneously into nude mice to explore tumour formation in vivo. The expression of CRNDE was significantly upregulated in NSCLC patients and cells. In addition, both loss and gain function assays revealed that CRNDE promoted NSCLC cell proliferation and growth both in vitro and in vivo. Moreover, CRNDE regulated the cell cycle transition from G0 /G1 stage to S stage and modulated the expression of CDK4, CDK6 and CCNE1. We further illustrated that CRNDE activated PI3K/AKT signalling in NSCLC cell lines. In conclusion, CRNDE was highly expressed in NSCLC malignant tissues and the heightened CRNDE strongly promoted NSCLC cell proliferation and growth through activating PI3K/AKT signalling; our results shed a light on utilizing CRNDE as a potential novel therapeutic target for the treatment of NSCLC.


Assuntos
Carcinoma Pulmonar de Células não Pequenas/patologia , Regulação Neoplásica da Expressão Gênica , Neoplasias Pulmonares/patologia , Fosfatidilinositol 3-Quinases/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , RNA Longo não Codificante/genética , Transdução de Sinais/genética , Animais , Carcinogênese/genética , Carcinoma Pulmonar de Células não Pequenas/genética , Linhagem Celular Tumoral , Transformação Celular Neoplásica , Ciclina E/metabolismo , Quinase 4 Dependente de Ciclina/metabolismo , Quinase 6 Dependente de Ciclina/metabolismo , Inibidor p16 de Quinase Dependente de Ciclina/metabolismo , Progressão da Doença , Técnicas de Silenciamento de Genes , Humanos , Neoplasias Pulmonares/genética , Camundongos , Proteínas Oncogênicas/metabolismo
13.
Plant Cell Rep ; 34(9): 1579-92, 2015 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-26007238

RESUMO

KEY MESSEAGE: 11 Cystatin genes in rice were identified, and their expression patterns were comprehensively analyzed, which reveals multiple roles in both seed development and plant response to environmental variations. Cystatin is a group of small proteins and known to inhibit the activities of cysteine proteases in the papain C1A and legumain C13 peptidase families in plants. Cystatin family genes have only been well characterized recently in a few plant species such as Hordeum vulgare and Nicotiana tabacum, which show their critical roles in programmed cell death and responses to biotic stresses. Up to now, little is known about cystatin family genes and their roles in Oryza sativa, a model plant for cereal biology study. Here, we identified 11 cystatin genes in rice genome. Comprehensive expression profile analysis reveals that cystatin family genes in rice display diverse expression pattern. They are temporally regulated at different developmental stages during the process of seed production and germination. Our experiments also reveal that the majority of cystatin genes are responsive to plant hormones and different environmental cues including cold, drought and other abiotic stresses, while some others are very stable under different stresses, indicating their fundamental roles in normal plant development. In addition, their distribution in rice chromosomes and their evolutionary relation to the members of Cystatin family in A. thaliana and N. tabacum have also been analyzed. These works suggest multiple roles of cystatin family genes in both seed development and plant response to environmental variations.


Assuntos
Cistatinas/genética , Genes de Plantas , Família Multigênica , Oryza/genética , Proteínas de Plantas/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Cromossomos de Plantas/genética , Clonagem Molecular , Sequência Conservada , Duplicação Gênica , Perfilação da Expressão Gênica , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Regulação da Expressão Gênica de Plantas/efeitos dos fármacos , Dados de Sequência Molecular , Oryza/efeitos dos fármacos , Filogenia , Reguladores de Crescimento de Plantas/farmacologia , Proteínas de Plantas/química , Plântula/efeitos dos fármacos , Plântula/genética , Plântula/crescimento & desenvolvimento , Sementes/efeitos dos fármacos , Sementes/genética , Sementes/crescimento & desenvolvimento
14.
Carcinogenesis ; 35(12): 2771-7, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25269803

RESUMO

The tumour-specific 'pre-metastatic niche' has emerged as a potential driving force for tumour metastasis and has been confirmed using mouse models of cancer metastasis. Vascular endothelial growth factor receptor-1(+) hematopoietic progenitor cells (HPCs) have been shown to play an important role in metastasis, forming a 'pre-metastatic niche' at designated sites for distant tumour progression. Here, CD133+ human umbilical hematopoietic progenitor cells (HUHPCs) were purified from human umbilical cord blood and expanded in vitro. We studied the effects of CD133+ HUHPCs on the growth and metastasis of four colorectal cancer (CRC) cell lines by using cell-to-cell co-culture. Our results revealed that CD133+ HUHPCs promoted the proliferation and invasion of CRC cells in vitro and enhanced tumour growth and metastasis in vivo. Moreover, CD133+ HUHPCs were observed in the pre-metastatic liver tissue using immunohistochemical analysis after co-injection of SW480/EGFP(+) cells and HUHPCs. Further experiments were therefore conducted to uncover the molecular mechanisms by which CD133+ HUHPCs influenced colon carcinogenesis and cancer progression. Extracted proteins were separated using the two-dimensional difference in gel electrophoresis technology. Among the differentially expressed proteins, mitogen-activated protein 4 kinase 4, stromal cell-derived factor-1, matrix metallopeptidase 9, calumenin, peripherin, leucine zipper, putative tumour suppressor 1 and guanidinoacetate methyltransferase attracted our attention. Western blot analysis further confirmed the differential expression of these proteins. Altogether, these results suggest that CD133+ HUHPCs may induce proliferation or metastasis of CRC cells and impact their derived proteins by providing a pre-metastatic microenvironment.


Assuntos
Antígenos CD/metabolismo , Movimento Celular , Proliferação de Células , Neoplasias Colorretais/patologia , Glicoproteínas/metabolismo , Células-Tronco Hematopoéticas/patologia , Neoplasias Hepáticas/secundário , Peptídeos/metabolismo , Antígeno AC133 , Animais , Western Blotting , Neoplasias Colorretais/metabolismo , Eletroforese em Gel Bidimensional , Feminino , Sangue Fetal/citologia , Sangue Fetal/metabolismo , Células-Tronco Hematopoéticas/metabolismo , Humanos , Neoplasias Hepáticas/metabolismo , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Células Tumorais Cultivadas , Ensaios Antitumorais Modelo de Xenoenxerto
15.
Opt Express ; 22(18): 22211-9, 2014 Sep 08.
Artigo em Inglês | MEDLINE | ID: mdl-25321597

RESUMO

A new-type slit spatial filter system with three lenses was proposed, in which the focal spot was turned into focal line by adding cylindrical lenses to increase focal area and then lower the focal intensity. Its performances on image relay, aperture matching and spatial filtering are comprehended by detailed theoretical calculations and numerical simulation. According to transmission spatial filter in national ignition facility, we present a replaceable slit spatial filter, which can reduce the overall length of laser system, improve the beam quality and suppress or even avoid the pinhole (slit) closure in the spatial filter.

16.
Heliyon ; 10(5): e27415, 2024 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-38486761

RESUMO

Background: To develop and validate a nomogram for predicting the probability of deep venous thrombosis (DVT) in patients with aneurysmal subarachnoid hemorrhage (aSAH) during the perioperative period, using clinical features and readily available biochemical parameters. Methods: The least absolute shrinkage and selection operator (LASSO) regression technique was employed for data dimensionality reduction and selection of predictive factors. A multivariable logistic regression analysis was conducted to establish a predictive model and nomogram for post-aSAH DVT. The discriminative ability of the model was determined by calculating the area under the curve (AUC). Results: A total of 358 aSAH patients were included in the study, with an overall incidence of DVT of 20.9%. LASSO regression identified four variables, including age, modified Fisher grade, total length of hospital stay, and anticoagulation therapy, as highly predictive factors for post-aSAH DVT. The patients were randomly divided into a modeling group and a validation group in a 6:4 ratio to construct the nomogram. The AUCs of the modeling and validation groups were 0.8511 (95% CI, 0.7922-0.9099) and 0.8633 (95% CI, 0.7968-0.9298), respectively. Conclusions: The developed nomogram exhibits good accuracy, discriminative ability, and clinical utility in predicting DVT, aiding clinicians in identifying high-risk individuals and implementing appropriate preventive and treatment measures.

17.
Materials (Basel) ; 16(3)2023 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-36769995

RESUMO

In the design of MV AC and DC spacers, the predominant factors are surface and interface conditions. Design is generally carried out on specifications and standards which are based on long-term experience and lab testing. However, the diffusion of power electronics with a trend to increase electric field, switching frequency, and rise time to achieve higher power density calls for an innovative, global approach to optimized insulation system design. A new methodology, based on field simulation, discharge modeling, and partial discharge inception measurements, called the three-leg approach, can form the basis to optimize insulation design for any type of supply voltage waveform. This paper focuses on the influence of the type of electrode on the inception and phenomenology of surface discharges and, as a consequence, on the interpretation of the results used for application of the three-leg approach. It is demonstrated that a typical electrode system used for insulating material testing can generate both gas and surface discharges at the triple point, when the electrodes have a smooth profile that is used to avoid corona or flashover. Hence, testing partial discharge may not provide a straightforward indication of the surface discharge inception and, thus, be partially misleading for insulation design. Another takeover is that such analysis must benefit from PD testing tools endowed with analytics able to provide automatic identification of the type of defect generating PD, i.e., internal, surface, and corona, since design and remedy actions can be taken, and adequate insulating materials developed, only knowing the type of source generating PD. Hence, testing partial discharge may not provide a straightforward indication of surface discharge inception and, thus, be partially misleading for insulation design. In addition to the importance of the three-leg approach to favor reliable and optimized design of insulation systems, there is a clear need to have a PD testing tool endowed with analytics. It should preferably be able to provide automatic identification of the type of defect generating PD, i.e., internal, surface, and corona.

18.
Materials (Basel) ; 16(13)2023 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-37445033

RESUMO

A bifunctional terahertz meta-material absorber with three layers is designed. The surface of the bifunctional meta-material absorber is a periodically patterned array composed of hybrid structures of vanadium dioxide (VO2) and metallic resonators; the middle layer is a nondestructive TOPAS film, and the bottom layer is a continuous metallic plane. Utilizing the phase-transition property of VO2, the responses of the meta-material absorber could be dynamically switched between triple-band absorption and ultra-broadband absorption. When VO2 is in the metallic state, an ultra-broadband absorption covering the bandwidth of 6.62 THz is achieved over the range from 4.71 THz to 11.33 THz. When VO2 is in the di-electric state, three absorption peaks resonated at 10.57 THz, 12.68 THz, and 13.91 THz. The physical mechanisms of the bifunctional meta-material absorber were explored by analyzing their near-field distributions. The effects of varying structural parameters on triple-band and ultra-broadband absorption were investigated. It is revealed that by optimizing the structure parameters, the number of absorption peaks could be increased for a certain sacrifice of absorption bandwidth. FDTD Solutions and CST Microwave Studio were used to simulate the data of the absorber, and similar results were obtained.

19.
Nanoscale ; 15(45): 18435-18446, 2023 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-37937951

RESUMO

Multi-band electromagnetically induced transparency (EIT) effects have attracted widespread attention due to their great application prospects. However, their realization is mainly based on the coupling of multiple sub-resonators that typically exceed the number of transparency peaks, resulting in complex structural designs and cumbersome preparation procedures. This paper reports a simple design of a terahertz metamaterial that can produce the triple-band EIT effect using two "big-bright" mode coupling of two sub-resonators. The design adopts the classical two-layer structure. A U-shaped split-ring resonator and a fork-shaped resonator form a periodic array on the surface of the flexible organic polymer material. Three transparency peaks around 0.59 THz, 1.07 THz, and 1.34 THz are experimentally realized, and their formation mechanisms are explored. Furthermore, the triple-band EIT metamaterial was prepared by the photolithography technology and characterized by terahertz time-domain spectroscopy. Theoretical simulation results agree well with experimental results. Sensing characteristics and slow light effects of the terahertz metamaterial are further discussed experimentally. The proposed triple-band EIT metamaterial having excellent properties, including thin size, good flexibility, simple and compact structure, and high sensing sensitivity, could provide guidance for the subsequent design and implementation of multifunctional multi-band EIT metamaterials.

20.
Front Plant Sci ; 14: 1126150, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37360715

RESUMO

Current research has long focused on soil organic carbon and soil aggregates stability. However, the effects of different long-term fertilization on the composition of yellow soil aggregates and the characteristics of the occurrence of organic carbon in the karst region of Southwest China are still unclear. Based on a 25-year long-term located experiment on yellow soil, soil samples from the 0-20 cm soil layer were collected and treated with different fertilizers (CK: unfertilized control; NPK: chemical fertilizer; 1/4 M + 3/4 NP: 25% chemical fertilizer replaced by 25% organic fertilizer; 1/2 M + 1/2 NP: 50% chemical fertilizer replaced by organic fertilizer; and M: organic fertilizer). In water-stable aggregates, soil aggregates stability, total organic carbon (TOC), easily oxidized organic carbon (EOC), carbon preservation capacity (CPC), and carbon pool management index (CPMI) were analyzed. The findings demonstrated that the order of the average weight diameter (MWD), geometric mean diameter (GWD), and macro-aggregate content (R0.25) of stable water aggregates was M > CK > 1/2M +1/2NP > 1/4M +3/4NP> NPK. The MWD, GWD, and R0.25 of NPK treatment significantly decreased by 32.6%, 43.2%, and 7.0 percentage points, respectively, compared to CK treatment. The order of TOC and EOC content in aggregates of different particle sizes was M > 1/2M +1/2NP > 1/4M +3/4NP> CK > NPK, and it increased as the rate of organic fertilizer increased. In macro-aggregates and bulk soil, the CPC of TOC (TOPC) and EOC (EOPC), as well as CPMI, were arranged as M > 1/2M +1/2NP > 1/4M +3/4NP> CK > NPK, but the opposite was true for micro-aggregates. In bulk soil treated with organic fertilizer, the TOPC, EOPC, and CPMI significantly increased by 27.4%-53.8%, 29.7%-78.1%, 29.7-82.2 percentage points, respectively, compared to NPK treatment. Redundancy analysis and stepwise regression analysis show that TOC was the main physical and chemical factor affecting the aggregates stability, and the TOPC in micro-aggregates has the most direct impact. In conclusion, the primary cause of the decrease in SOC caused by the long-term application of chemical fertilizer was the loss of organic carbon in macro-aggregates. An essential method to increase soil nutrient supply and improve yellow soil productivity was to apply an organic fertilizer to increase aggregates stability, storage and activity of SOC in macro-aggregates.

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