Single-mode tunable laser emission in the single-exciton regime from colloidal nanocrystals

Whispering-gallery-mode resonators have been extensively used in conjunction with different materials for the development of a variety of photonic devices. Among the latter, hybrid structures, consisting of dielectric microspheres and colloidal core/shell semiconductor nanocrystals as gain media, have attracted interest for the development of microlasers and studies of cavity quantum electrodynamic effects. Here we demonstrate single-exciton, single-mode, spectrally tuned lasing from ensembles of optical antenna-designed, colloidal core/shell CdSe/CdS quantum rods deposited on silica microspheres. We obtain single-exciton emission by capitalizing on the band structure of the specific core/shell architecture that strongly localizes holes in the core, and the two-dimensional quantum confinement of electrons across the elongated shell. This creates a type-II conduction band alignment driven by coulombic repulsion that eliminates non-radiative multi-exciton Auger recombination processes, thereby inducing a large exciton–bi-exciton energy shift. Their ultra-low thresholds and single-mode, single-exciton emission make these hybrid lasers appealing for various applications, including quantum information processing

ENVIRONMENTAL SURROUNDINGS AND PERSONAL WELL-BEING IN URBAN CHINA

We examine the relationship between atmospheric pollution, water pollution, traffic congestion, access to parkland and personal well-being using a survey administered across six Chinese cities in 2007. In contrast to existing studies of the determinants of well-being by economists, which have typically employed single item indicators to measure well-being, we use the Personal Well-Being Index (PWI). We also employ the Job Satisfaction Survey (JSS) to measure job satisfaction, which is one of the variables for which we control when examining the relationship between environmental surroundings and personal well-being. Previous research by psychologists has shown the PWI and JSS to have good psychometric properties in western and Chinese samples. A robust finding is that in cities with higher levels of atmospheric pollution and traffic congestion, respondents report lower levels of personal well-being ceteris paribus. Specifically, we find that a one standard deviation increase in suspended particles or sulphur dioxide emissions is roughly equivalent to a 12-13 per cent reduction in average monthly income in the six cities.China, Environment, Pollution, Personal Well-Being.

The effect of fog on the probability density distribution of the ranging data of imaging laser radar

This paper outlines theoretically investigations of the probability density distribution (PDD) of ranging data for the imaging laser radar (ILR) system operating at a wavelength of 905 nm under the fog condition. Based on the physical model of the reflected laser pulses from a standard Lambertian target, a theoretical approximate model of PDD of the ranging data is developed under different fog concentrations, which offer improved precision target ranging and imaging. An experimental test bed for the ILR system is developed and its performance is evaluated using a dedicated indoor atmospheric chamber under homogeneously controlled fog conditions. We show that the measured results are in good agreement with both the accurate and approximate models within a given margin of error of less than 1%

Hesitant Triangular Fuzzy Information Aggregation Operators Based on Bonferroni Means and Their Application to Multiple Attribute Decision Making

We investigate the multiple attribute decision-making (MADM) problems with hesitant triangular fuzzy information. Firstly, definition and some operational laws of hesitant triangular fuzzy elements are introduced. Then, we develop some hesitant triangular fuzzy aggregation operators based on Bonferroni means and discuss their basic properties. Some existing operators can be viewed as their special cases. Next, we apply the proposed operators to deal with multiple attribute decision-making problems under hesitant triangular fuzzy environment. Finally, an illustrative example is given to show the developed method and demonstrate its practicality and effectiveness

Oriented ice eddy detection network based on the Sentinel-1 dual-polarization data

The complex convergence of cold and warm ocean currents in the Nordic Seas provides suitable conditions for the formation and development of eddies. In the Marginal Ice Zones (MIZs), ice eddies contribute to the accelerated melting of surface sea ice by facilitating vertical heat transfer, which influences the evolution of the marginal ice zone and plays an indirect role in regulating global climate. In this paper, we employed high-resolution synthetic aperture radar (SAR) satellite imagery and proposed an oriented ice eddy detection network (OIEDNet) framework to conduct automated detection and spatiotemporal analysis of ice eddies in the Nordic Seas. Firstly, a high-quality RGB false-color imaging method was developed based on Sentinel-1 dual-polarization (HH+HV) Extra-Wide Swath (EW) mode products, effectively integrating denoising algorithms and image processing techniques. Secondly, an automatic ice eddy detection method based on oriented bounding boxes (OBB) was constructed to identify the ice eddy and output features such as horizontal scales, eddy centers and rotation angles. Finally, the characteristics of the detected ice eddies in the Nordic Seas during 2022-2023 were systematically analyzed. The results demonstrate that the proposed OIEDNet exhibits significant performance in ice eddy detection

Fabrication and Properties of Carbon- Encapsulated Cobalt Nanoparticles over NaCl by CVD

Carbon-encapsulated cobalt (Co@C) nanoparticles, with a tunable structure, were synthesized by chemical vapor deposition using Co nanoparticles as the catalyst and supported on a water-soluble substrate (sodium chloride), which was easily removed by washing and centrifugation. The influences of growth temperature and time on the structure and magnetic properties of the Co@C nanoparticles were systematically investigated. For different growth temperatures, the magnetic Co nanoparticles were encapsulated by different types of carbon layers, including amorphous carbon layers, graphitic layers, and carbon nanofibers. This inferred a close relationship between the structure of the carbon-encapsulated metal nanoparticles and the growth temperature. At a fixed growth temperature of 400 °C, prolonged growth time caused an increase in thickness of the carbon layers. The magnetic characterization indicated that the magnetic properties of the obtained Co@C nanoparticles depend not only on the graphitization but also on the thickness of the encapsulated carbon layer, which were easily controlled by the growth temperatures and times. Optimization of the synthesis process allowed achieving relatively high coercivity of the synthesized Co@C nanoparticles and enhancement of its ferromagnetic properties, which make this system promising as a magnetic material, particularly for high-density magnetic recording applications

Mechanism of inhibition of growth and metastasis of colon cancer by celecoxib analog OSU-03013 via wnt signaling pathway

OSU-03013 is a structurally modified analog of celecoxib. This study probed the antitumor activity of OSU-03013 on colon cancer (CC) and explored its possible mechanism. CCK-8 method was used to evaluate the activity of OSU-03013 on CC cell SW480 and normal colon epithelial cell FHC, and the anti-proliferation effect of OSU-03013 was detected by CCK-8 and colony formation assay. In addition, flow cytometry and Annexin V-FITC/PI were applied to detect apoptosis of SW480 cells, and Transwell was to detect cell migration and invasion. β-catenin, c-myc, and Wnt1 genes were assessed by RT-qPCR, and E-cadherin, N-cadherin, and β-catenin, c-myc, mTOR, p-mTOR, and Wnt1 proteins were detected by Western Blot. OSU-03013 had dose-dependent and time-dependent antitumor activity on SW480 cells, which can promote tumor cell apoptosis, up-regulate E-cadherin, and down-regulate β-catenin, c-myc, Wnt1, and N-cadherin. OSU-03013 has anti-tumor activity on CC cells. The anti-cancer mechanism of OSU-03013 is achieved by inhibiting the activation of Wnt pathway genes and inhibiting tumor invasion and metastasis. This study provides a scientific basis for the clinical application of OSU-03013 in the treatment of CC

Residual Characteristics and Dietary Risk Assessment of Dinotefuran and Tolfenpyrad in Tea Processing

To clarify the residual characteristics of dinotefuran tolfenpyrad microemulsion during tea planting, drying and brewing, standardized field trials of pesticide registration residues were conducted in 10 provinces including Shandong and Zhejiang. Dietary risk assessment models were compared with and without adjustment of processing factors. The samples were extracted using acetonitrile containing 5% formic acid, salted out, purified by dispersed solid phase extraction, detected by ultra-high performance liquid chromatography-tandem mass spectrometry, and quantified by an external standard method. In the range of 0.005–0.500 µg/mL, a good linear relationship was obtained between the concentrations of dinotefuran and its metabolites as well as tolfenpyrad and their response peak areas (R2 > 0.99). The average recovery rates of dinotefuran and its metabolites 1-methyl-3-(tetrahydro-3-furylmethyl)guanidine (DN) and 1-methyl-3-(tetrahydro-3-furylmethyl)urea (UF) in fresh and dried tea leaves spiked at 0.05, 1.00, 20.00 and 50.00 mg/kg and in tea infusion spiked at 0.05, 0.10 and 5.00 mg/kg ranged from 74% to 103%, with relative standard deviations (RSDs) of 1%–9%. The spiked recovery rates of tolfenpyrad were between 75% and 95%, with RSDs of 1%–6%. The limit of quantitation (LOQ) was 0.05 mg/kg for all the analytes. In the case of the application of 20% dinotefuran·tolfenpyrad microemulsion at the recommended dose, both the national estimated daily intake (NEDI) for supervised trials median residue (STMR) adjusted with the drying factor of dinotefuran (containing its metabolites) in fresh tea leaves and that in dried tea leaves were 4.08 mg, accounting for 32.4% of the acceptable daily intake (ADI). The NEDI for STMR of tolfenpyrad adjusted with the drying factor in fresh tea leaves was 0.175 81 mg, accounting for 46.5% of the ADI, and the NEDI for STMR of tolfenpyrad in dried tea leaves was 0.189 25 mg, accounting for 50.1% of the ADI. According to different risk assessment models, the long-term exposure risk to both dinotefuran and tolfenpyrad was less than 100%. The national estimated short-term intake (IESTI) of dinotefuran (containing its metabolites) remained at the same risk level before and after processing factor adjustment, which was lower than the acute reference dose (ARfD) of 1 mg/kg. The IESTI of tolfenpyrad was 3.46 × 10-4 mg/kg, which was lower than the ARfD of 0.01 mg/kg, and tolfenpyrad residue was below the detectable level under the method established in this study, so no brewing facter and corresponding IESTI were obtained. In conclusion, the application of 20% dinotefuran·tolfenpyrad microemulsion on tea plants is safe at the recommended dose, and the risk of long-term and acute dietary exposure to dinotefuran and tolfenpyrad residues in tea is within the acceptable range. The risk assessment models with processing factor adjustment are closer to the actual risk level