作者机构：
[Hu, Zhangli; Kuang, Jiamin; Fu, Wenmo; Hu, Longxin] College of Chemistry Materials, Hengyang Normal University, Hengyang, China;Hunan Provincial Key Laboratory of Functional Metal-Organic Compounds, Hengyang, China;[Zhang, Huanian] College of Chemistry, Xiangtan University, Xiangtan, China;[Lai, Hua; Liu, Xing] College of Chemistry Materials, Hengyang Normal University, Hengyang, China<&wdkj&>Hunan Provincial Key Laboratory of Functional Metal-Organic Compounds, Hengyang, China
通讯机构：
[Hua Lai; Xing Liu] C;College of Chemistry Materials, Hengyang Normal University, Hengyang, China<&wdkj&>Hunan Provincial Key Laboratory of Functional Metal-Organic Compounds, Hengyang, China
摘要：
Brominated dyes, 2C-n (n = 1-5), 3C-4 and 4C-4, were prepared through bromination of three carbazole-based D-π-A dyes, 2C, 3C and 4C with N-bromosuccinimide (NBS). The detailed structures of the brominated dyes were confirmed by (1)H NMR spectroscopy and mass spectrometry (MS). The introduction of the Br atom on the 1,8-positon of carbazole moieties led to blueshifted UV-vis and photoluminescence (PL) spectra, increased initial oxidation potentials and enlarged dihedral angles, indicating bromination enhanced non-planarity of the dye molecules. In the hydrogen production experiments, with the increase of the Br content in brominated dyes, the photocatalytic activity increased continuously (except 2C-1). The dye-sensitized Pt/TiO(2,) 2C-4@T, 3C-4@T and 4C-4@T, exhibited high hydrogen production efficiencies of 655.4, 877.9 and 905.6 μmol h(-1) g(-1), respectively, which were 4-6-fold higher than those of 2C@T, 3C@T and 4C@T. The enhanced performance of photocatalytic hydrogen evolution was attributed to decreased dye aggregation resulting from the highly non-planar molecular structures of the brominated dyes.
期刊：
Computational Methods and Function Theory,2023年:1-11 ISSN：1617-9447
通讯作者：
Ponnusamy, S
作者机构：
[Li, Liulan] Hengyang Normal Univ, Coll Math & Stat, Hunan Prov Key Lab Intelligent Informat Proc & App, Hengyang 421002, Hunan, Peoples R China.;[Ponnusamy, S; Ponnusamy, Saminathan] Indian Inst Technol Madras, Dept Math, Chennai 600036, India.;[Ponnusamy, S; Ponnusamy, Saminathan] Lomonosov Moscow State Univ, Moscow Ctr Fundamental & Appl Math, Moscow, Russia.;[Wirths, Karl-Joachim] Tech Univ Carolo Wilhelmina Braunschweig, Inst Algebra & Anal, D-38106 Braunschweig, Germany.
通讯机构：
[Ponnusamy, S ] I;Indian Inst Technol Madras, Dept Math, Chennai 600036, India.;Lomonosov Moscow State Univ, Moscow Ctr Fundamental & Appl Math, Moscow, Russia.
关键词：
Meromorphic functions;Taylor coefficients;Laurent series
摘要：
In this article, we consider the family of functions f meromorphic in the unit disk
$${\mathbb D}=\{z:\,|z| < 1\}$$
with a pole at the point
$$z=p$$
, a Taylor expansion
$$\begin{aligned} f(z)= z+\sum _{k=2}^{\infty } a_kz^k, \quad |z|<p, \end{aligned}$$
and satisfying the condition
$$\begin{aligned} \left| \left( \frac{z}{f(z)}\right) -z\left( \frac{z}{f(z)}\right) '-1\right| <\lambda \qquad \text {for all }z\in {\mathbb D}, \end{aligned}$$
for some
$$\lambda $$
,
$$0<\lambda < 1$$
. We denote this class by
$$\mathcal {U}_p(\lambda )$$
and we shall prove a representation theorem for the functions in this class. As consequences, we get a simple proof for the estimates of
$$|a_2|$$
and obtain inequalities for the initial coefficients of the Laurent series of
$$f\in \mathcal {U}_p(\lambda )$$
at its pole. In [8] it had been conjectured that for
$$f\in \mathcal {U}_p(\lambda )$$
the inequalities
$$\begin{aligned} |a_n|\le \frac{1}{p^{n-1}}\sum _{k=0}^{n-1}(\lambda p^2)^k, \quad n\ge 2, \end{aligned}$$
are valid. We provide a counterexample to this conjecture for the case
$$n=3$$
.
期刊：
Journal of Electronic Imaging,2023年32(4) ISSN：1017-9909
通讯作者：
Tian, XM
作者机构：
[Guo, Yanyu; Xiao, Yanting; Tian, Xiaomei] Hengyang Normal Univ, Coll Comp Sci & Technol, Hengyang, Peoples R China.
通讯机构：
[Tian, XM ] H;Hengyang Normal Univ, Coll Comp Sci & Technol, Hengyang, Peoples R China.
关键词：
Object detection;Detection and tracking algorithms;Neck;Head;Convolution;Feature fusion;Feature extraction;Water;Evolutionary algorithms;Image processing
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：
[Tan, L.; Wu, Y. -j.; Tan, L; Huang, Z. -x.; Liu, H.; Liu, Y. -x.; Wu, YJ] Hengyang Normal Univ, Coll Chem & Mat Sci, Hunan Engn Res Ctr Monitoring & Treatment Heavy Me, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421001, Peoples R China.
通讯机构：
[Tan, L; Wu, YJ ] H;Hengyang Normal Univ, Coll Chem & Mat Sci, Hunan Engn Res Ctr Monitoring & Treatment Heavy Me, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421001, Peoples R China.
关键词：
Ag coating;Surfactant;Zinc-metal battery;Zinc dendrite
摘要：
Rechargeable aqueous zinc (Zn) batteries are promising for large energy storage due to their low cost, high safety, and environmental compatibility, but their commercialization is hindered by the severe irreversibility of Zn metal anodes as exemplified by water-induced side reactions (H2 evolution and Zn corrosion) and dendrite growth. In this work, hierarchical layered silver-coated zinc anode under the assistance of anionic surfactant (trisodium citrate) was prepared for long-time cycle stabilities of zinc stripping and plating, where Ag coating has a strong affinity to Zn adatoms and hierarchical structure exhibits a positive role in inducing the (002) plane preferred-orientation growth of Zn phase. Benefiting from these features, hierarchical Ag-coated zinc anode was able to operate stability for more than 1200 cycles compared with the pure zinc anode at 2 mA/cm(2) for 1 mAh/cm(2), and an asymmetric cell shows superior Coulombic efficiency of similar to 99.6% over 800 cycles at a current density of 1 mA/cm(2) and 0.5 mAh/ cm(2), as well as a long cycling stability of 500 cycles with capacity of 115 mAh/g in MnO2||H-Zn@Ag full batteries. This work provides a new insight to improve the performance of Zn-metal batteries.(c) 2023 Elsevier Ltd. All rights reserved.
作者机构：
[He, Quanguo; Zhou, Chuanqin; Chen, Aiting; Zuo, Jingsong; Tang, Nana; Shi, Shuting; Wei, Yanping; He, QG] Hunan Univ Technol, Sch Life Sci & Chem, Zhuzhou 412007, Peoples R China.;[Deng, Peihong; Deng, PH] Hengyang Normal Univ, Dept Chem & Mat Sci, Key Lab Organometall New Mat, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421008, Peoples R China.
通讯机构：
[Deng, PH ; He, QG ] H;Hunan Univ Technol, Sch Life Sci & Chem, Zhuzhou 412007, Peoples R China.;Hengyang Normal Univ, Dept Chem & Mat Sci, Key Lab Organometall New Mat, Key Lab Funct Met Organ Cpds Hunan Prov, Hengyang 421008, Peoples R China.
关键词：
MnS/Co 3 S 4 hybrids;Graphene oxide;Electrochemical reduction;Acetaminophen;Voltammetric sensor
摘要：
In this work, hollow tubular manganese-cobalt sulfide (MnS/Co3S4) hybrids were synthesized using a hydrothermal method and anchored on graphene oxide (GO) by simple ultrasonic dispersion. The nanocomposites were modified onto glassy carbon electrode (GCE) surface by a drop-coating method. After potentiostatic reduction, GO was converted into electrochemically reduced graphene oxide (ERGO), and a sensitive sensor, denoted as MnS/Co3S4-electrochemically reduced graphene oxide modified glassy carbon electrode (MnS/ Co3S4-ERGO/GCE), was constructed for acetaminophen (AC) detection. The electrochemical sensing performance of MnS/Co3S4-ERGO/GCE was evaluated in detail. The experimental results show that MnS/Co3S4-ERGO/ GCE has excellent electrocatalytic activity for the oxidation of AC. The kinetic process for the electrooxidation of AC on the MnS/Co3S4-ERGO/GCE was studied and the measurement parameters optimized. Under optimal conditions, the oxidation peak current is linear with the concentration of AC in the range of 0.01-20 & mu;M and 20-80 & mu;M, with a detection limit of 6.0 nM. Based on the high sensitivity and excellent selectivity of MnS/Co3S4ERGO/GCE, the method has been applied for the determination of AC in commercial tablets and human serum samples, with satisfactory recoveries of 98.8%-101.5% and 98.6%-102.8%, indicating high accuracy of the proposed method.
期刊：
International Journal of Environmental Research and Public Health,2023年20(4) ISSN：1661-7827
通讯作者：
Zhi Zhou
作者机构：
[Rongying Zeng] College of Chemistry and Material Science, Hengyang Normal University, Hengyang 421001, China;[Bowen Lei; Zhi Zhou; Xiuyu Long; Guangyong Zeng; Chunxia Ding; Yu Ouyang; Jing Wang] School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, China
通讯机构：
[Zhi Zhou] S;School of Chemistry and Materials Science, Hunan Agricultural University, Changsha 410128, China
摘要：
Abstract: The excessive application of phosphate fertilizers easily causes water eutrophication. Phosphorus recovery by adsorption is regarded as an effective and simple intervention to control water bodies’ eutrophication. In this work, a series of new adsorbents, layered double hydroxides (LDHs)-modified biochar (BC) with different molar ratios of Mg2+ and Fe3+, were synthesized based on waste jute stalk and used for recycling phosphate from wastewater. The prepared LDHs-BC4 (the molar ratio of Mg/Fe is 4:1) has significantly high adsorption performance, and the recovery rate of phosphate is about 10 times higher than that of the pristine jute stalk BC. The maximum adsorption capacity of LDHs-BC4 for phosphate was 10.64 mg-P/g. The main mechanism of phosphate adsorption mainly includes electrostatic attraction, ion exchange, ligand exchange, and intragranular diffusion. Moreover, the phosphate-adsorbed LDHs-BC4 could promote mung bean growth, which indicated the recovery phosphate from wastewater could be used as a fertilizer. Keywords: phosphate; LDHs; biochar; recycling; fertilizer
作者机构：
[Chen, Zhongwen] Hengyang Normal Univ, Coll Econ & Management, Hengyang 421002, Peoples R China.;[Shi, Yanlin] Macquarie Univ, Dept Actuarial Studies & Business Analyt, Sydney, NSW 2109, Australia.;[Shu, Ao] Hunan Univ, Business Sch, Changsha 410012, Peoples R China.
通讯机构：
[Ao Shu] B;Business School, Hunan University, Changsha 410012, China
关键词：
mortality rates;Lee-Carter model;time-varying coefficients;rotated age pattern;life expectancy
摘要：
Abstract: Influential existing research has suggested that rather than being static, mortality declines decelerate at young ages and accelerate at old ages. Without accounting for this feature, the forecast mortality rates of the popular Lee–Carter (LC) model are less reliable in the long run. To provide more accurate mortality forecasting, we introduce a time-varying coefficients extension of the LC model by adopting the effective kernel methods. With two frequently used kernel functions, Epanechnikov (LC-E) and Gaussian (LC-G), we demonstrate that the proposed extension is easy to implement, incorporates the rotating patterns of mortality decline and is straightforwardly extensible to multi-population cases. Using a large sample of 15 countries over 1950–2019, we show that LC-E and LC-G, as well as their multi-population counterparts, can consistently improve the forecasting accuracy of the competing LC and Li–Lee models in both single- and multi-population scenarios. Keywords: mortality rates; Lee–Carter model; time-varying coefficients; rotated age pattern; life expectancy
摘要：
Two tricyclohexyltin aryloxyacetates (C1, C2) have been synthesized by the reaction of tricyclohexyltin hydroxide with 1,3-phenylenedioxydiacetic acid (L1) or 3-(N,N'-dicarboxymethyl)aminophenoxyacetic acid (L2), respectively. The structures were characterized by elemental analyses, IR, H-1, C-13 NMR, and X-ray diffraction. The structure of complex C1 has been previously reported, C2 is a novel complex. The results of thermal stability analysis confirmed that the two complexes contain solvent molecules, so they can only exist stably below 70(o)C. The results of herbicidal activity showed that C1 and C2 had moderate growth regulation effects on Alfalfa.
摘要：
In recent years, carbon-based materials catalyzing peroxymonosulfate (PMS) for green degradation of persistent or-ganic pollutants have attracted increasing attention. However, PMS activation by hydrochar composite (e.g. hydrochar-montomorillonite) has rarely been investigated. Herein, a simple preparation, low-cost and eco-friendly catalyst of hydrochar-montmorillonite composite (HC-Mt) was prepared to firstly catalyze PMS for the degradation of dicamba (DIC). The as-prepared HC-Mt showed a remarkably better catalyzing performance for PMS than pure hydrochar (HC) due to its good physicochemical characteristics and abundant oxygen-containing groups. Further-more, the electron spin resonance (ESR) and quenching tests revealed that active species such as SO4 center dot-, center dot OH and O2 center dot- all participated in the degradation process. DIC sites on C6, Cl 10, and O15 exhibited higher reactivity according to the density functional theory (DFT) calculation, which were easily attacked by active species. The DIC degradation mainly occurred via hydroxyl substitution, decarboxylation, oxidation and ring-cleavage and finally most of the inter-mediates were mineralized into CO2 and H2O. Finally, the phytotoxicity assessment was measured by the germination growth situation of tobacco and mung beans in the presence of DIC (with or without treatment by HC-Mt/PMS). The result showed that HC-Mt/PMS could significantly reduce the phytotoxicity of DIC to crops, suggesting that catalyzing PMS using HC-Mt was environmentally friendly. Therefore, this work did not only provide a novel catalyzing PMS strategy using hydrochar composite for wastewater treatment, but also give a new idea for herbicide phytotoxicity management.
期刊：
Journal of Mathematics,2023年2023 ISSN：2314-4629
作者机构：
[Wang, Keyan; Hu, Boxia] Hengyang Normal Univ, Sch Math & Stat, Hengyang 421008, Hunan, Peoples R China.;[Hu, Boxia] Hunan Univ, Sch Math, Changsha 410082, Hunan, Peoples R China.
摘要：
In this paper, two efficient two-grid algorithms for the convection-diffusion problem with a modified characteristic finite element method are studied. We present an optimal error estimate in L-p-norm for the characteristic finite element method unconditionally, while all previous works require certain time-step restrictions. To linearize the characteristic method equations, two-grid algorithms based on the Newton iteration approach and the correction method are applied. The error estimate and the convergence result of the two-grid method are derived in detail. It is shown that the coarse space can be extremely coarse and achieve asymptotically optimal approximations as long as the mesh sizes H=Oh(1/3) in the first algorithm and H=Oh(1/4) in the second algorithm, respectively. Finally, two numerical examples are presented to demonstrate the theoretical analysis.
