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1.
J Anim Ecol ; 92(11): 2189-2200, 2023 11.
Artigo em Inglês | MEDLINE | ID: mdl-37766488

RESUMO

In cooperatively breeding birds, why do some individuals breed independently but others have to help at home? This question has been rarely addressed despite its fundamental importance for understanding the evolution of social cooperation. We address it using 15 years of data from Tibetan ground tits Pseudopodoces humilis where helpers consist of younger males. Since whether younger males successfully breed depends critically on their chances to occupy territories nearby home, our analytic strategy is to identify the determinants of individual differences in gaining territory ownership among these ready-to-breed males. Across widowed, last-year helper and yearling males, an age advantage was evident in inheriting resident territories, occupying adjacent vacancies and budding off part of adjacent territories, which left some last-year helpers and most yearling males to take the latter two routes. These males were more likely to acquire a territory if they were genetically related to the previous or current territory owners; otherwise they remained on natal territories as helpers. The relatedness effect can arise from the prior residence advantage established in the preceding winter when younger males followed their parents to perform kin-directed off-territory forays. Our research highlights the key role of local kinship in determining younger males' territory acquisition and thus their fate in terms of independent reproduction versus help. This finding provides insight into the formation of kin-based, facultative cooperative societies prevailing among vertebrates.


Assuntos
Núcleo Familiar , Passeriformes , Humanos , Masculino , Animais , Comportamento Social , Passeriformes/genética , Cruzamento , Reprodução , Comportamento Cooperativo
2.
J Clin Lab Anal ; 36(1): e24136, 2022 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-34820903

RESUMO

BACKGROUNDS: Free-wall rupture (FWR) has a high mortality rate. We aimed to find sensitive predictive indicators to identify high-risk FWR patients by exploring the predictive values of neutrophil percentage-to-albumin ratio (NPAR) and monocyte-to-lymphocyte ratio (MLR) on patients with acute myocardial infarction (AMI). METHODS: 76 FWR patients with AMI were collected, and then 228 non-CR patients with AMI were randomly selected (1:3 ratio) in this retrospective study. The independent influencing factors of FWR were evaluated by univariate and multivariate logistic regression analysis. The receiver-operating characteristic (ROC) curve analysis was applied to evaluate the predictive value of NPAR and MLR for FWR. RESULTS: According to the results of multivariate logistic regression analysis, emergency percutaneous coronary intervention (PCI) (OR = 0.27, 95% CI: 0.094-0.751, p = 0.012), angiotensin-converting enzyme inhibitor (ACEI)/angiotensin receptor blocker (ARB) treatment (OR = 0.17, 95% CI: 0.044-0.659, p = 0.010), NPAR (OR = 2.69, 95% CI: 1.031-7.044, p = 0.043), and MLR (OR = 5.99, 95% CI: 2.09-17.168, p = 0.001) were the influencing factors of the FWR patients with AMI, independently. Additionally, the NPAR and MLR were the predictors of FWR patients, with AUC of 0.811 and 0.778, respectively (both p < 0.001). CONCLUSIONS: In summary, the emergency PCI and ACEI/ARB treatment were independent protective factors for FWR patients with AMI, while the increase of MLR and NPAR were independent risk factors. What's more, NPAR and MLR are good indicators for predicting FWR.


Assuntos
Albuminas/análise , Leucócitos/fisiologia , Infarto do Miocárdio , Idoso , Idoso de 80 Anos ou mais , Feminino , Humanos , Inflamação , Contagem de Leucócitos , Masculino , Pessoa de Meia-Idade , Infarto do Miocárdio/sangue , Infarto do Miocárdio/diagnóstico , Infarto do Miocárdio/epidemiologia , Infarto do Miocárdio/fisiopatologia , Prognóstico , Estudos Retrospectivos , Ruptura
3.
Sensors (Basel) ; 21(4)2021 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-33671572

RESUMO

In this paper, a radial basis neural network adaptive sliding mode controller (RBF-NN ASMC) for nonlinear electromechanical actuator systems is proposed. The radial basis function neural network (RBF-NN) control algorithm is used to compensate for the friction disturbance torque in the electromechanical actuator system. An adaptive law was used to adjust the weights of the neural network to achieve real-time compensation of friction. The sliding mode controller is designed to suppress the model uncertainty and external disturbance effects of the electromechanical actuator system. The stability of the RBF-NN ASMC is analyzed by Lyapunov's stability theory, and the effectiveness of this method is verified by simulation. The results show that the control strategy not only has a better compensation effect on friction but also has better anti-interference ability, which makes the electromechanical actuator system have better steady-state and dynamic performance.

4.
Nanotechnology ; 31(40): 405708, 2020 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-32512559

RESUMO

We investigate a polarized Raman characterization of Zr2X (X = C, N), excited by two commonly used laser lines with wavelenghts of 532 nm and 633 nm, based on first principle calculations. The Raman spectra of Zr2X has two Raman shift peaks which correspond to the degenerate in-plane vibration mode (Eg) and out-of-plane vibration mode (A1g). Furthermore, we study the polarization angle dependent Raman intensity for both Eg and A1g modes in parallel and perpendicular configurations for these two materials. We found that the polarization angle dependent Raman intensity is isotropic when the laser line is perpendicular to the Zr2X plane. There are either only two maxima, or two maxima larger than the other maxima, in the parallel configuration when the laser line is parallel to the Zr2X plane, which might be useful in identifying the orientation of Zr2X in experiment. The results show that the locations of the maxima of the polarization angle dependent Raman intensity rarely depend on the exciting laser line, except that of the Eg mode of Zr2N.

5.
Sensors (Basel) ; 20(21)2020 Oct 23.
Artigo em Inglês | MEDLINE | ID: mdl-33113983

RESUMO

Human body motion tracking is a key technique in robotics, virtual reality and other human-computer interaction fields. This paper proposes a novel simple-structure Kalman filter to improve the accuracy of human body motion tracking, named the Second EStimator of the Optimal Quaternion Kalman Filter (E2QKF). The new algorithm is the combination of the Second Estimator of the Optimal Quaternion (ESOQ-2) algorithm, the linear Kalman filter and the joint angle constraint method. In the proposed filter, the ESOQ-2 algorithm is used to produce an observation quaternion by preprocessing accelerometer and magnetometer measurements. The compensation for the accelerometer added in the ESOQ-2 algorithm is to eliminate the influence of human body motion acceleration included in the results. The state vector of the filter is the quaternion, which is calculated with gyroscope measurements, and the Kalman filter is to calculate the optimal quaternion by fusing the state quaternion and the observation quaternion. Therefore, the filter becomes a simple first-order linear system model, which avoids the linearization error of measurement equations and reduces the computational complexity. Furthermore, the joint angle constraint is considered in the proposed algorithm, which makes the results more accurate. To verify the accuracy of the proposed algorithm, inertial/magnetic sensors are used to perform the upper limb motion experiment, and the result of E2QKF (without joint angle constraint) is compared with an optical motion capture system and two traditional methods. Test results demonstrate the effectiveness of the proposed filter: the root mean square error (RMSE) of E2QKF is less than 2.0° and the maximum error is less than 4.6°. The result of E2QKF (with joint angle constraint) is compared with E2QKF (without joint angle constraint). Test results demonstrate the superiority of E2QKF (with joint angle constraint): the joint angle constraint method can further improve the accuracy of human body motion tracking.


Assuntos
Algoritmos , Corpo Humano , Aceleração , Humanos , Fenômenos Magnéticos , Movimento (Física)
6.
Phys Chem Chem Phys ; 21(3): 1059-1066, 2019 Jan 17.
Artigo em Inglês | MEDLINE | ID: mdl-30398495

RESUMO

Using density functional theory, we investigated the vibrational properties and Raman spectra of pristine blue phosphorene and fluorinated blue phosphorene. The fluorinated blue phosphorene possesses a Dirac cone at the K point (about 310 cm-1). The shape of the Dirac cone remains unchanged under different tensile strains. The Raman tensor and thus angle-dependent Raman intensities of all Raman active modes are calculated for the polarizations of scattered light parallel and perpendicular to that of the incident light. The characteristics of angle-dependent Raman intensities are discussed. Moreover, the polarization direction averaged non-resonant Raman spectra of pristine blue phosphorene and fluorinated blue phosphorene are compared with that of germanene and black phosphorene.

7.
Entropy (Basel) ; 20(1)2018 Jan 22.
Artigo em Inglês | MEDLINE | ID: mdl-33265167

RESUMO

For spin-1 condensates, the spatial degrees of freedom can be considered as being frozen at temperature zero, while the spin-degrees of freedom remain free. Under this condition, the entanglement entropy has been derived exactly with an analytical form. The entanglement entropy is found to decrease monotonically with the increase of the magnetic polarization as expected. However, for the ground state in polar phase, an extremely steep fall of the entropy is found when the polarization emerges from zero. Then the fall becomes a gentle descent after the polarization exceeds a turning point.

8.
J Chem Phys ; 145(20): 204704, 2016 Nov 28.
Artigo em Inglês | MEDLINE | ID: mdl-27908142

RESUMO

To understand laser-assisted field evaporation of semiconductors and insulators at the microscopic level, we study the time evolution of the electronic and atomic structure of a MgO cluster in high electrostatic fields subjected to strong laser pulses. We find that the critical laser intensity for evaporation decreases linearly as the electrostatic field strength increases. The optical absorption enhancement in high electrostatic field is confirmed by the redshift of the optical absorption spectra, the reduction of the energy gap, and the increase of the absorption cross section.

9.
Mol Cell Biochem ; 385(1-2): 115-23, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24122418

RESUMO

Visceral and subcutaneous adipose tissue depots have distinct features and contribute differentially to metabolic disease. Therefore, the adipogenic potential of different fat depots was investigated and found to be higher in subcutaneous compared with visceral stromal-vascular fraction (SVF), which contains adipocyte precursor cells. This increased differentiation capacity was not due to elevated numbers of Lin-Sca1+CD29+CD34+Pref1+ precursor cells, as the number of preadipocytes was higher in visceral than in subcutaneous SVF. The secreted heat-sensitive factors from the SVF inhibited adipocyte differentiation more in visceral than in subcutaneous SVF. In order to explore secreted proteins that potentially inhibit differentiation, the secretome of murine SVF was analyzed by mass spectrometry, which resulted in the identification of 113 secreted proteins with an overlap of 42 % between subcutaneous and visceral SVF. Comparison of the mRNA expression in SVF from both depots revealed 16 transcripts that were significantly expressed more in visceral than in subcutaneous SVF. A functional differentiation screen identified seven potential inhibitory candidates: biglycan, decorin, bone morphogenic protein 1, epidermal growth factor-containing fibulin-like extracellular matrix protein 2, elastin microfibril interfacer 1, matrix gla protein, and Sparc-like 1. For further verification, murine recombinant decorin or Sparc-like 1 was added to the media during the differentiation process leading to a dose-dependent decrease in adipogenesis. Further analysis will be necessary to assess the impact of the other candidates on adipocyte differentiation.


Assuntos
Adipogenia , Tecido Adiposo/citologia , Comunicação Parácrina , Animais , Western Blotting , Extratos Celulares , Técnicas de Silenciamento de Genes , Células HEK293 , Humanos , Gordura Intra-Abdominal/metabolismo , Masculino , Espectrometria de Massas , Camundongos , Camundongos Endogâmicos C57BL , Reação em Cadeia da Polimerase , Células Estromais/metabolismo , Frações Subcelulares/metabolismo , Gordura Subcutânea/metabolismo
10.
Phys Chem Chem Phys ; 16(30): 15927-33, 2014 Aug 14.
Artigo em Inglês | MEDLINE | ID: mdl-24963886

RESUMO

The deformation and disintegration of a graphene nanoribbon under external electrostatic fields are investigated by first principle quantum mechanical calculations to establish its stability range. Zigzag edges terminated by various functional groups are considered. By analyzing the phonon spectrum, the critical fracture field for each edge structure is obtained. It is found that different terminal groups on the zigzag graphene nanoribbons lead to different fracture patterns at different fracture fields. The failure mechanism is demonstrated to involve both the carbon bond alternation feature across the ribbon and the terminal group electronegativity.

11.
Zhonghua Yi Xue Za Zhi ; 94(14): 1055-9, 2014 Apr 15.
Artigo em Zh | MEDLINE | ID: mdl-24851887

RESUMO

OBJECTIVE: To explore the relationship between thyroid-stimulating hormone (TSH) and metabolic syndrome (MS) and its components in euthyroid male elders. METHODS: For this cross-sectional study, 307 euthyroid male elders aged over 60 years participating in a routine annual health screening examination at our hospital during May-June 2011 were enrolled. Their mean age was (72.6 ± 7.9) years. Height, weight, blood pressure, blood glucose, blood lipids, fasting insulin levels and thyroid functions (TT3, TT4, FT3, FT4, TSH, TgAb & TPOAb) were measured. And the association of thyroid functions and the presence of MS and its components was analyzed. RESULTS: The prevalence of MS was 40.7% (125/307). The TSH level was significantly higher in the MS and obese group than that in control group ((2.6 ± 1.1) vs (2.4 ± 1.0) mU/L, P = 0.014; (2.7 ± 1.1) vs (2.3 ± 1.1)mU/L, P = 0.007). The prevalence of MS and obesity showed a gradual increase according to the TSH tertiles. When comparing subjects in the highest and lowest tertile of TSH, the former group demonstrated 1.872 and 1.904-fold increases in the odds ratio for obesity and MS after adjusting for age and homeostasis model assessment for insulin resistance (HOMA-IR) (95%CI: 1.051-3.332, P = 0.033; 95%CI: 1.070-3.387, P = 0.028) . Logistic regression analysis showed that the TSH levels were independent influencing factors for MS in male elders (OR = 1.324, 95%CI:1.042-1.683) . CONCLUSION: High circulating TSH level, albeit normal, is associated with elevated risk for metabolic syndrome in male elders.


Assuntos
Síndrome Metabólica/sangue , Síndrome Metabólica/epidemiologia , Tireotropina/sangue , Idoso , Idoso de 80 Anos ou mais , Estudos Transversais , Humanos , Masculino , Síndrome Metabólica/fisiopatologia , Pessoa de Meia-Idade , Prevalência
12.
Bioengineering (Basel) ; 11(6)2024 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-38927775

RESUMO

Natural killer cells (NKCs) are non-specific immune lymphocytes with diverse morphologies. Their broad killing effect on cancer cells has led to increased attention towards activating NKCs for anticancer immunotherapy. Consequently, understanding the motion characteristics of NKCs under different morphologies and modeling their collective dynamics under cancer cells has become crucial. However, tracking small NKCs in complex backgrounds poses significant challenges, and conventional industrial tracking algorithms often perform poorly on NKC tracking datasets. There remains a scarcity of research on NKC dynamics. In this paper, we utilize deep learning techniques to analyze the morphology of NKCs and their key points. After analyzing the shortcomings of common industrial multi-object tracking algorithms like DeepSORT in tracking natural killer cells, we propose Distance Cascade Matching and the Re-Search method to improve upon existing algorithms, yielding promising results. Through processing and tracking over 5000 frames of images, encompassing approximately 300,000 cells, we preliminarily explore the impact of NKCs' cell morphology, temperature, and cancer cell environment on NKCs' motion, along with conducting basic modeling. The main conclusions of this study are as follows: polarized cells are more likely to move along their polarization direction and exhibit stronger activity, and the maintenance of polarization makes them more likely to approach cancer cells; under equilibrium, NK cells display a Boltzmann distribution on the cancer cell surface.

13.
Nanomaterials (Basel) ; 14(7)2024 Mar 29.
Artigo em Inglês | MEDLINE | ID: mdl-38607141

RESUMO

In recent studies, it has been discovered that phonons can carry angular momentum, leading to a series of investigations into systems with three-fold rotation symmetry. However, for systems with two-fold screw rotational symmetry, such as α-MoO3, there has been no relevant discussion. In this paper, we investigated the pseudoangular momentum of phonons in crystals with two-fold screw rotational symmetry. Taking α-MoO3 as an example, we explain the selection rules in circularly polarized Raman experiments resulting from pseudoangular momentum conservation, providing important guidance for experiments. This study of pseudoangular momentum in α-MoO3 opens up a new degree of freedom for its potential applications, expanding into new application domains.

14.
Rev Sci Instrum ; 95(4)2024 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-38668694

RESUMO

An extremely stable megavolt (MV) level DC voltage source is the key foundation for many scientific instruments, and the need for accurate measurement and long-term real-time monitoring of its output voltage is increasingly urgent. The utilization of conventional resistive voltage dividers for measurements introduces leakage currents, resulting in considerable measurement errors. The non-contact generating voltmeter (GVM) sensor based on electric field measurement has a simple structure and a low cost, making it expected to be an effective solution. Currently, most research on GVM sensors focuses on the measurement of weak electric fields at kV/m levels with significant interference. In this paper, an improved high-precision non-contact GVM sensor was designed. A DC voltage test platform was built, and the effects of the sampling resistor and motor rotation speed on the measurement results were discussed. The relative combined uncertainty of the improved GVM sensor reached 0.042%, which satisfied the urgent need for MV level DC voltage source measurement. The improved GVM sensor can provide an effective reference for measuring the output voltage of a metal-enclosed MV level DC voltage source or the potential of a suspended electrode.

15.
Ecol Evol ; 14(6): e11559, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38863720

RESUMO

Understanding how age and body size vary across elevations can provide insights into the evolution of life-history traits in animals. In the present study, we compared the demographic (using skeletochronology) and morphological traits of the Tibetan toad (Bufo tibetanus) between two populations from different elevational habitats (2650 vs. 3930 m). We found that (1) the mean age and body size of females were significantly greater than those of males in both populations; (2) both sexes of toads from the higher elevation tended to be significantly older in age and larger in body size; (3) there was a significant positive relationship between age and body size within each sex of the toad at both elevations; and (4) growth rates varied between the two populations, with the higher rate observed in the lower-elevation population. Our results suggested that factors other than age, such as elevation-associated temperature, influence the observed differences in body size between the two populations. Future research at a broader range of elevations should focus on these factors and evaluate their influence on animal growth patterns.

16.
Aging Male ; 16(3): 132-6, 2013 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-23876123

RESUMO

BACKGROUND: Nocturnal hypoglycemia was a common and serious problem among patients with type 2 diabetes (T2DM), especially in the elderly. This study investigated whether fasting glucose was an indicator of nocturnal hypoglycemia in elderly male patients with T2DM. METHODS: A total of 291 elderly male type 2 diabetic patients who received continuous glucose monitoring (CGM) between January 2007 and January 2011 were enrolled in the study. The association of fasting glucose and nocturnal hypoglycemia based on CGM data was analyzed, comparing with bedtime glucose. RESULTS: Based on CGM data, patients with nocturnal hypoglycemia had significantly lower fasting glucose (5.88 ± 1.29 versus 6.92 ± 1.32 mmol/L) and bedtime glucose (7.33 ± 1.70 versus 8.01 ± 1.95 mmol/L) than patients without nocturnal hypoglycemia (both p < 0.01). Compared with the highest quartile, the lowest quartile of fasting glucose had a significantly increased risk of nocturnal hypoglycemia after the multiple adjustments (pfor trend < 0.001). However, this association did not appear in bedtime glucose. When the prediction of nocturnal hypoglycemia either by fasting glucose or bedtime glucose using the area under receiver operating characteristic (ROC) curve, fasting glucose but not bedtime glucose, was an indicator of nocturnal hypoglycemia, with an area under the ROC curve (AUC) of 0.714 (95% CI: 0.653 ∼ 0.774, p < 0.001). On the ROC curve, the Youden index was maximal when fasting glucose was 6.1 mmol/L. CONCLUSIONS: Fasting glucose may be a convenient and clinically useful indicator of nocturnal hypoglycemia in elderly male patients with T2DM. Risk of nocturnal hypoglycemia significantly increased when fasting glucose was less than 6.1 mmol/L.


Assuntos
Glicemia/análise , Diabetes Mellitus Tipo 2/complicações , Jejum/sangue , Hipoglicemia/etiologia , Idoso , Idoso de 80 Anos ou mais , Biomarcadores/sangue , Automonitorização da Glicemia , Diabetes Mellitus Tipo 2/sangue , Humanos , Masculino , Pessoa de Meia-Idade , Curva ROC
17.
Zhonghua Yi Xue Za Zhi ; 93(40): 3202-6, 2013 Oct 29.
Artigo em Zh | MEDLINE | ID: mdl-24405541

RESUMO

OBJECTIVE: To explore the influencing factors of glycemic variability in elderly patients with type 2 diabetes. METHODS: A total of 337 elderly patients received continuous glucose monitoring (CGM) from January 2007 to January 2011. The evaluation variables of glycemic variability included standard deviation of blood glucose (SDBG), mean amplitude of glycemic excursion (MAGE), absolute means of daily differences (MODD) and postprandial glucose excursion (PPGE). The normal reference value of glycemic variability was defined according to the diagnostic criteria of Chinese Diabetes Society guideline. RESULTS: The difference of glycemic variability was compared by gender, age and diabetic duration. The values of SDBG, MAGE, MODD and PPGE in females were all higher than those in males (P < 0.05) and no difference existed between various age groups. The level of glycemic variability increased gradually with the extension of diabetic duration (P < 0.01). Logistic regression analysis showed that gender (MAGE: OR = 0.44, P = 0.023; SDBG: OR = 0.39, P = 0.023), diabetic duration (MAGE: OR = 1.58, P = 0.006; SDBG: OR = 2.42, P < 0.001) and HbA1c (MAGE: OR = 2.44, P < 0.001; SDBG: OR = 2.68, P < 0.001) were significant influencing factors of glycemic variability (MAGE/SDBG) in elderly patients with type 2 diabetes (P < 0.05), but not age, body mass index (BMI) or diabetic neuropathy. CONCLUSION: Gender, diabetic duration and HbA1c are significant influencing factors of glycemic variability while age, BMI or diabetic neuropathy has no association with glycemic variability in elderly patients with type 2 diabetes.


Assuntos
Glicemia/metabolismo , Diabetes Mellitus Tipo 2/sangue , Idoso , Feminino , Humanos , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Estudos Retrospectivos
18.
Curr Zool ; 69(1): 76-81, 2023 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-36974150

RESUMO

Altruism is difficult to explain evolutionarily and to understand it, there is a need to quantify the benefits and costs to altruists. Hamilton's theory of kin selection argues that altruism can persist if the costs to altruists are offset by indirect fitness payoffs from helping related recipients. Nevertheless, helping nonkin is also common and in such situations, the costs must be compensated for by direct benefits. While previous researchers tended to evaluate the indirect and direct fitness in isolation, we expect that they have a complementary interaction where altruists are associated with recipients of different relatedness within a population. The prediction is tested with 12 years of data on lifetime reproductive success for a cooperatively breeding bird, Tibetan ground tits Pseudopodoces humilis. Helpers who helped distantly related recipients gained significantly lower indirect benefits than those who helped closely related recipients, but the opposite was true for direct fitness, thereby making these helpers have an equal inclusive fitness. Helping efforts were independent of helpers' relatedness to recipients, but those helping distantly related recipients were more likely to inherit the resident territory, which could be responsible for their high direct reproductive success. Our findings provide an explanatory model for the widespread coexistence of altruists and recipients with varying relatedness within a single population.

19.
Nanomaterials (Basel) ; 13(17)2023 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-37686945

RESUMO

Two-dimensional van der Waals materials could be used as electron emitters alone or stacked in a heterostructure. Many significant phenomena of two-dimensional van der Waals field emitters have been observed and predicted since the landmark discovery of graphene. Due to the wide variety of heterostructures that integrate an atomic monolayer or multilayers with insulator nanofilms or metallic cathodes by van der Waals force, the diversity of van der Waals materials is large to be chosen from, which are appealing for further investigation. Until now, increasing the efficiency, stability, and uniformity in electron emission of cold cathodes with two-dimensional materials is still of interest in research. Some novel behaviors in electron emission, such as coherence and directionality, have been revealed by the theoretical study down to the atomic scale and could lead to innovative applications. Although intensive emission in the direction normal to two-dimensional emitters has been observed in experiments, the theoretical mechanism is still incomplete. In this paper, we will review some late progresses related to the cold cathodes with two-dimensional van der Waals materials, both in experiments and in the theoretical study, emphasizing the phenomena which are absent in the conventional cold cathodes. The review will cover the fabrication of several kinds of emitter structures for field emission applications, the state of the art of their field emission properties and the existing field emission model. In the end, some perspectives on their future research trend will also be given.

20.
Chemosphere ; 333: 138907, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37169091

RESUMO

To ascertain the reaction variables on o-chloroaniline (o-ClA) mineralization, total nitrogen (TN) removal rate, and N-species distribution, o-ClA was subjected to catalytic supercritical water oxidation (CSCWO) in a fused quartz tube reactor (FQTR). The findings demonstrated that when the temperature, reaction time, and excess oxidant were 400 °C, 90 min, and 150%, respectively, the mineralization rate of o-ClA could reach more than 95%. Moreover, potential degradation pathways of o-ClA in supercritical water oxidation (SCWO) was proposed according to the GC-MS results. TN removal rate is significantly impacted by Ru/rGO, despite the fact that its catalytic effect on the mineralization of o-ClA was not particularly noteworthy. Compared with no catalyst, the TN removal rate of o-ClA obviously increased from 44.1% to 90.3% at 400 °C, 10 wt% Ru loading, 90 min and 200% excess oxidant. In addition, N-species distribution in SCWO and CSCWO were also investigated. Results indicated that the Ru/rGO catalyst could accelerate the oxidation of ammonia-N and convert it to nitrate-N, promoting N2 generation. Finally, the possible N transformation pathway in CSCWO of o-ClA was proposed. As a result, this work offers fundamental information about o-ClA catalytic oxidation removal in the SCWO process.


Assuntos
Poluentes Químicos da Água , Água , Nitrogênio , Oxirredução , Compostos de Anilina , Oxidantes
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