作者机构：
[Li, Suxun] Changan Univ, Sch Earth Sci & Resources, Xian 710054, Peoples R China.;[Feng, Chang; Yang, Liu; Li, Suxun] Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Peoples R China.;[Feng, C] Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Peoples R China.
通讯机构：
[Feng, C ] ;Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Peoples R China.
关键词：
driving factors;evapotranspiration;MODIS;spatiotemporal patterns;standard deviation ellipse;Xiangjiang River Basin
摘要：
Evapotranspiration (ET) is a crucial parameter in the process of the hydrological cycle. It is of great significance for water resource management and the improvement of ecological systems in the Xiangjiang River Basin (XRB) to explore the spatial and temporal dynamic characteristics of ET. Based on MOD16, this study revealed the characteristics of spatial and temporal patterns of ET in the XRB from 2000 to 2020. We first applied land use data and change rate for overall trend analysis on ET. Then, we obtained spatiotemporal migration routes of ET through standard deviation ellipse (SDE). Furthermore, we demonstrated the effects of monsoon and urban expansion on ET change. Accordingly, we observed the following novel spatiotemporal patterns of ET: (1) while the ET of artificial surfaces decreased from 2000 to 2020, the change rate in most regions of the XRB was 8.83%, indicating that the overall trend of ET in the XRB was increasing. (2) At 10-year intervals, the SDE center of ET all migrated in a clockwise direction. (3) The correlation between precipitation and ET is more obvious than that between temperature and ET. (4) With the direct effects of monsoon on precipitation in East Asia, we found that the changes in precipitation are consistent with the ET change.
摘要：
High-performance photodetectors hold promising potential in optical communication and imaging systems. However, conventional counterparts are suffering narrow detection range, high power consumption, and poor polarization sensitivity. Characteristics originating from switchable polarization in ferroelectrics can be used to optimize the photo-to-electric procedure and improve the photodetection performance. In this regard, we constructed a configuration by integrating 2-dimensional molybdenum disulfide (MoS(2)) with ferroelectric lithium niobate (LiNbO(3)), resulting in the MoS(2)/LiNbO(3) heterostructured photodetector. Benefiting from the pyroelectric effect of LiNbO(3), the limitation of bandgap on the detection range can be broken, thus broadening the response band of the detector to 365 to 1,064 nm, as well as enabling the self-powered characteristic. Meanwhile, high carrier mobility and decent light absorbance of MoS(2) introduce robust light-matter interactions with the underlying LiNbO(3), leading to ultrafast rise/fall times of ≈150 μs/250 μs and switching ratios of up to ≈190. Moreover, the highest responsivity, specific detectivity, and external quantum efficiency achieved were 17.3 A·W(-1), 4.3 × 10(11) Jones, and 4,645.78%, respectively. Furthermore, because of the anisotropy of the spontaneous-polarized LiNbO(3) substrate, the photocurrent of the device achieved a dichroic ratio of 7.42, comparing favorably to most MoS(2)-based photodetectors. This work demonstrates the integration potential between ferroelectric LiNbO(3) and 2-dimensional materials for high-performance photodetection.
通讯机构：
[Xiaohui Ling] L;Laboratory for Spin-Orbit Photonics, College of Physics and Electronic Engineering, Hengyang Normal University, Hengyang 421002, People's Republic of China
关键词：
angular momentum;photonic orbital Hall effect;vortex phase;mode decomposition
摘要：
The photonic orbital Hall effect (POHE) refers to the vortex-dependent beam shifts, which is generally believed to result from the conversion of intrinsic orbital angular momentum (IOAM) to extrinsic orbital angular momentum (EOAM). However, the physical mechanism of the POHE, such as how the IOAM is converted to the EOAM, remains further elucidation. In this paper, we re-examine the POHE of a vortex beam with additional IOAM illuminating at an optically thin slab by means of vortex mode decomposition. By considering the competition and coupling between the radial and azimuthal vortex harmonics of the abnormal mode in the transmitted beam, it is found that the underlying mechanism of the POHE is in fact a spin-to-orbital angular momentum (OAM) conversion process. And the IOAM carried by the incident beam is directly superimposed on the OAM obtained during the conversion. Our findings not only offer an alternative perspective for understanding the POHE, but also exhibit application potential in orbit-orbit and spin-orbit optical components.
期刊：
IEEE Transactions on Multimedia,2023年:1-13 ISSN：1520-9210
作者机构：
[Gaobo Yang; Dewang Wang; Xin Liao] School of Computer Science and Electronic Engineering, Hunan University, Changsha, China;School of Computer Science and Technology, Hengyang Normal University, Hengyang, China;[Shengchun Wang] College of Information Science and Electronic Engineering, Hunan Normal University, Changsha, China;[Jiyou Chen] School of Computer Science and Electronic Engineering, Hunan University, Changsha, China<&wdkj&>School of Computer Science and Technology, Hengyang Normal University, Hengyang, China
摘要：
Full-reference image dehazing quality assessment (FR-IDQA) evaluates the visual quality of a dehazed image by measuring its differences with a clear reference. The existing FR-IDQA methods are not convincing due to the lack of well-aligned datasets of hazy and clear image pairs and the limited hand-crafted features make it difficult to simulate the complicated perception by the human visual system (HVS). In this work, we build a real-world image dataset, namely RW-Haze, which comprises natural hazy images and their well-aligned clear references. Each clear image is paired with several hazy images with diverse haze levels from slight to heavy. Meanwhile, the existing FR-IDQA works evaluate the dehazed image quality in a global manner, without considering local haze distributions in the original hazy image. Actually, the perceived haze in a natural hazy image is not uniformly distributed, and the haze density varies with scene depth. Based on this priori observation, we design a haze density-aware convolutional neural network (CNN), namely DehIQA, for FR-IDQA. It adopts transfer learning to alleviate the issue of lacking sufficient labeled data. Specifically, we divide image dehazing assessment into two tasks. The source task is to classify unpaired clear and hazy images, which enforces the deep network to learn haze-related features. The target task is image quality assessment, which is achieved by transferring the trained model for the source task to the target task. Considering the fact that the perceived distortion in a dehazed image is also not uniform, we present a haze density-aware mechanism into DehIQA, which assigns different weights for different local regions in a dehazed image in terms of the dark channel of the original hazy image. Extensive experimental results show that DehIQA outperforms the state-of-the-art (SOTA) works on the benchmark dataset and achieves better consistency with human perceptions.
通讯机构：
[Yun-Wu Li; Jin-Sheng Zhao] S;[Yi-Jin Wu] K;Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, and School of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252000, P. R. China<&wdkj&>Key Laboratory of Functional Metal-Organic Compounds of Hunan Province, Hunan Province Universities Key Laboratory of Functional Organometallic Materials, College of Chemistry and Material Science, Hengyang Normal University, Hengyang 421008, P. R. China
摘要：
The cathodic product Li(2)CO(3), due to its high decomposition potential, has hindered the practical application of rechargeable Li-CO(2)/O(2) batteries. To overcome this bottleneck, a Pt/FeNC cathodic catalyst is fabricated by dispersing Pt nanoparticles (NPs) with a uniform size of 2.4 nm and 8.3 wt % loading amount into a porous microcube FeNC support for high-performance rechargeable Li-CO(2)/O(2) batteries. The FeNC matrix is composed of numerous two-dimensional (2D) carbon nanosheets, which is derived from an Fe-doping zinc metal-organic framework (Zn-MOF). Importantly, using Pt/FeNC as the cathodic catalyst, the Li-CO(2)/O(2) (V(CO(2))/V(O(2)) = 4:1) battery displays the lowest overpotential of 0.54 V and a long-term stability of 142 cycles, which is superior to batteries with FeNC (1.67 V, 47 cycles) and NC (1.87 V, 23 cycles) catalysts. The FeNC matrix and Pt NPs can exert a synergetic effect to decrease the decomposition potential of Li(2)CO(3) and thus enhance the battery performance. In situ Fourier transform infrared (FTIR) spectroscopy further confirms that Li(2)CO(3) can be completely decomposed under a low potential of 3.3 V using the Pt/FeNC catalyst. Impressively, Li(2)CO(3) exhibits a film structure on the surface of the Pt/FeNC catalysts by scanning electron microscopy (SEM), and its size can be limited by the confined space between the carbon sheets in Pt/FeNC, which enlarges the better contacting interface. In addition, density functional theory (DFT) calculations reveal that the Pt and FeNC catalysts show a higher adsorption energy for Li(2)CO(3) and Li(2)CO(4) intermediates compared to the NC catalyst, and the possible discharge pathways are deeply investigated. The synergetic effect between the FeNC support and Pt active sites makes the Li-CO(2)/O(2) battery achieve optimal performance.
关键词：
long memory;regime switching;FIEGARCH;MRS-FIEGARCH
摘要：
Recent research suggests that long memory can be caused by regime switching and is easily confused with it. However, if the causes of confusion were properly controlled, they could be distinguished. Motivated by this idea, our study aims to distinguish between the long memory and regime switching of financial volatility. We firstly modeled the long memory and regime switching of volatility using the Fractionally Integrated Exponential GARCH (FIEGARCH) and Markov Regime-Switching EGARCH (MRS-EGARCH) frameworks, respectively, and performed a simulation study on their finite-sample properties when innovations followed a non-normal distribution. Subsequently, we demonstrated the confusion between the FIEGARCH and MRS-EGARCH processes using simulations. A recent study theoretically proved that the time-varying smoothing probability series can induce the presence of significant long memory in the regime-switching process. To control for its effect, the two-stage two-state FIEGARCH and MRS-FIEGARCH frameworks are proposed. The Monte Carlo studies showed that both frameworks can effectively distinguish between the pure FIEGARCH and pure MRS-EGARCH processes. When the MRS-FIEGARCH model was further employed to fit series generated with the MRS-FIEGARCH process, it outperformed the ordinary FIEGARCH model. Finally, an empirical study of NASDAQ index return was conducted to demonstrate that our MRS-FIEGARCH model can provide potentially more reliable long-memory estimates, identify the volatility states and outperform both the FIEGARCH and MRS-EGARCH models.
摘要：
Unmanned missions have become more and more popular in recent years. The related technologies of unmanned ground vehicles and unmanned aerial vehicles are growing rapidly, but research on unmanned surface vehicles (USVs) is rare. Water surface object detection algorithms play a crucial role in the field of USVs. However, achieving an object detection algorithm that balances speed and accuracy in the presence of interference is a difficult challenge. We proposed a network, DBCR-YOLO, that improved the detection accuracy while meeting real-time requirements. Based on YOLOv5, we added an additional detection head for detecting tiny objects. Then, we replaced the downsampling in YOLOv5's backbone network with the proposed double sampling mechanism to solve the problem that paying attention to the key features of objects cannot be done in the downsampling process of YOLOv5. Finally, we substituted the proposed BCR neck for YOLOv5's neck, thus improving the fusion of features between different scales based on fewer parameters and fewer calculations. We tested our network on the water surface object detection dataset. Compared with YOLOv5, DBCR-YOLO improved the detection accuracy by 3.4%. At the same time, DBCR-YOLO achieved the highest accuracy in comparison with other networks. (c) 2023 SPIE and IS&T
作者机构：
[Deng, Zhiwei; Quan, Bin] Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Peoples R China.;[Quan, Bin] Hengyang Base Int Ctr Space Technol Nat & Cultural, Hengyang 421002, Peoples R China.
通讯机构：
[Quan, B ] H;Hengyang Normal Univ, Coll Geog & Tourism, Hengyang 421002, Peoples R China.;Hengyang Base Int Ctr Space Technol Nat & Cultural, Hengyang 421002, Peoples R China.
关键词：
land use and land cover change;Intensity Analysis;change detection;Chang-Zhu-Tan Metropolitan Region
通讯机构：
[Yanliang Tan] C;College of Physics and Electronic Engineering , Hengyang Normal University, Hengyang, Hunan Province 421008, China
摘要：
Radon-222 (Rn-222) exhalation rate is vital for estimating radiation risk from many kinds of materials. AlphaGUARD measures the radon concentration based on the ionization chamber principle, which is currently recognized as a reference instrument to measure radon. In China, measurements of radon exhalation rate are performed by AlphaGUARD operated in flow-through mode on a reference device to verify measurement accuracy. These measurements are performed in both open and closed loop. AlphaGUARD can fast rapidly the variation of the radon concentration in the chamber, which is tightly pressed against the surface of the medium to accumulate the exhaled radon. When the model is used to obtain the radon exhalation rate, the radon exhalation rates obtained by nonlinear data fitting on the measured radon concentrations are similar to the reference value of the device. The difference of radon exhalation rate values of six measurements is small.
摘要：
According to the methodical examination of the physicochemical, sensory, and antioxidant properties of flavored yogurts which fortified with different amounts of Lentinula edodes stipe (LES), we found that the LES was beneficial to improve some physicochemical (pH, viable lactic acid bacteria density, and syneresis) and sensory properties (fermented odor and taste quality), and the antioxidant activity (ABTS and DPPH radical scavenging activity) of the plain yogurt, which has the potential to be used in functional yogurt. The results above were also helpful for the rational utilization of LES toward value‐added products. Abstract The Lentinula edodes stipe (LES), a by‐product of L. edodes fruiting body processing, is rich in dietary fiber, protein, and polysaccharides, which can be served as the functional ingredient in dairy products. In this study, stirred yogurts fortified with 1%, 2%, and 3% LES were prepared, and the effects of LES on the changes in color, pH, titratable acidity (TA), viable lactic acid bacteria (LAB) cells, syneresis, viscosity, texture, and antioxidant activity of the flavored yogurt were monitored at the beginning and the end of storage. The LES decreased the lightness, increased the red–green color values and yellow–blue color values, decreased the pH values, and increased the contents of TA, the viable LAB cells, and the antioxidant activity of yogurt samples in a dose‐dependent manner. The addition of LES showed double‐edged effects on the texture of yogurt, which significantly reduced firmness and viscosity but decreased the syneresis. Compared with plain yogurt, the 2% LES‐fortified yogurt exhibited similar index values of texture parameters and higher scores of the appearance, fermented odor, taste quality, and overall acceptance, suggesting that this might be the optimal dose for industrial production. After cold storage for 28 days, pH values of all yogurt samples further decreased with increasing of TA. Interestingly, syneresis of LES‐fortified yogurt decreased and the viable LAB cells and antioxidant activity of 3% LES‐fortified yogurt slightly decreased. Therefore, LES is beneficial to improve physicochemical, sensory, and antioxidant properties of yogurt, which has the potential to be used in functional dairy products.
作者机构：
[Chen, Shaolin; Chen, SL] Hengyang Normal Univ, Coll Math & Stat, Hengyang 421008, Hunan, Peoples R China.
通讯机构：
[Chen, SL ] H;Hengyang Normal Univ, Coll Math & Stat, Hengyang 421008, Hunan, Peoples R China.
关键词：
Heinz type inequality;Lipschitz continuous;Polyharmonic mapping;Quasiconformal mapping
摘要：
Suppose that f satisfies the following: (1) the polyharmonic equation triangle(m) f = triangle(triangle(m-1) f ) = phi(m) (phi(m) is an element of C((B-n) over bar, R-n)), (2) the boundary conditions triangle(0) f = phi(0), triangle(1) f = phi 1, ..., triangle(m-1) f = phi(m-1 )on Sn-1 (phi (j) is an element of C(Sn-1, R-n) for j is an element of {0, 1, ... , m - 1} and Sn-1 denotes the boundary of the unit ball B-n), and (3) f (0) = 0, where n >= 3 and m >= 1 are integers. Initially, we prove a Schwarz type lemma and use it to obtain a Heinz type inequality of mappings satisfying the polyharmonic equation with the above Dirichlet boundary value conditions. Furthermore, we establish a Bloch type theorem of mappings satisfying the above polyharmonic equation, which gives an answer to an open problem in Chen and Ponnusamy, (2019). Additionally, we show that if f is a K-quasiconformal self-mapping of Bn satisfying the above polyharmonic equation, then f is Lipschitz continuous, and the Lipschitz constant is asymptotically sharp as K -> 1(+) and parallel to phi(j) parallel to infinity -> 0(+) for j is an element of {1, ... , m}.(c) 2023 Royal Dutch Mathematical Society (KWG). Published by Elsevier B.V. All rights reserved.
