摘要：
To tackle the concern of hexavalent chromium (Cr(VI)) contamination, a photocatalytic adsorbent, chitosan/ carbon dots modified cellulose nanofibrils/ZIF-8 gel bead (CCCZ), was synthesized as an effective and easily separable material for Cr(VI) removal. A comprehensive analysis of CCCZ encompassing diverse analytical techniques was conducted to explore its morphology, structure, optical properties, as well as its adsorption and photocatalytic behaviors. Adsorption experiments revealed the exceptional adsorption capacity of CCCZ for Cr (VI), with a maximum capacity of 500.08 mg/g, surpassing that of original chitosan gel bead by a factor of 3.4. Moreover, the results from the adsorption and photocatalytic experiments provided robust evidence of CCCZ's superior performance. CCCZ exhibited an apparent rate constant of 0.1150 min-1, which was significantly higher (5.7 times) than that of pure ZIF-8. Remarkably, CCCZ exhibited an efficient regeneration capacity alongside its substantiated long-term stability. This study yields invaluable insights into the development of novel, highefficiency photocatalytic adsorbents featuring facile separability, directed toward the effective alleviation of Cr(VI) contaminant.
摘要：
We theoretically explore the conditions for generating optical bistability (OB) in a heterodimer comprised of a semiconductor quantum dot (SQD) and a metallic nanoshell (MNS). The MNS is made of a metallic nanosphere as a core and a dielectric material as a shell. For the specific hybrid system considered, the bistable effect appears only if the frequency of the pump field is equal to (or slightly less than) the exciton frequency for a proper shell thickness. Bistability phase diagrams, when plotted, show that the dipole-induced bistable region can be greatly broadened by changing the shell thickness of the MNS in a strong exciton-plasmon coupling regime. In particular, we demonstrate that the multipole polarization not only narrows the bistable zone but also enlarges the corresponding thresholds for a given intermediate scaled pumping intensity. On the other hand, when the SQD couples strongly with the MNS, the multipole polarization can also significantly broaden the bistable region and induce a great suppression of the FWM (four-wave mixing) signal for a fixed shell thickness. These interesting findings offer a fresh understanding of the bistability conditions in an SQD/MNS heterodimer, and may be useful in the fabrication of high-performance and low-threshold optical bistable nanodevices.
摘要：
Let S-j(z) = epsilon(j) + (z- epsilon(j))/2 be an iterated function system, where epsilon(j) = e(2j pi i/3) for j = 0, 1, 2. Then, there exists a uniform self-similar measure mu supported on a compact set K, which is the attractor of {S (j)}(j=0)(2). The Hausdorff dimension of the attractor K is alpha = log 3/ log 2. Let F(z) =integral K(z - omega)(-1)d mu(omega) be the Cauchy transform of mu. In this paper, we consider the Hardy space and the multiplier property of F. We prove that F ' belongs to Hp for 0 < p < 1/(2 - alpha) and that F is a multiplier of some class of function space.
期刊：
Chemical Engineering Journal,2023年470:144087 ISSN：1385-8947
通讯作者：
Xin Guo<&wdkj&>Yiqiang Wu
作者机构：
[Zhang, Xuefeng; Huang, Huijian; Qi, Xinmiao; Zhang, Ning; Wang, Yuanlan; Guo, Xin] College of Science, Central South University of Forestry and Technology, Changsha 410004, China;Yuelushan Laboratory Non-wood Forests Variety Innovation Center, Changsha 410004, China;[Qiao, Jianzheng; Wu, Yiqiang] College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China;[Peng, Junwen] College of Science, Central South University of Forestry and Technology, Changsha 410004, China<&wdkj&>Yuelushan Laboratory Non-wood Forests Variety Innovation Center, Changsha 410004, China
通讯机构：
[Xin Guo; Yiqiang Wu] C;College of Science, Central South University of Forestry and Technology, Changsha 410004, China<&wdkj&>College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
摘要：
To address the pollution of antibiotics in water resources, a novel cellulose nanofibrils modified with carbon dots-graft-polyacrylamide/Zeolitic imidazolate framework-8 composite hydrogel (CZCH) was synthesized in this study for simultaneous adsorption and detection of tetracycline (TC). The morphology, structure, fluorescent properties, and adsorption and sensing capabilities of CZCH were comprehensively characterized using various analytical techniques. The results demonstrated the CZCH's remarkable adsorption capacity for TC that reached a maximum of 810.36 mg/g. The Langmuir model provided an excellent fit for the adsorption isotherm, while the pseudo-secondary model accurately described the adsorption kinetics. Thermodynamic analysis revealed that the adsorption process was characterized by an endothermic reaction. Impressively, the CZCH maintained 85.6% retention of its initial adsorption capacity even after undergoing five consecutive adsorption/desorption cycles. Moreover, the synthesized CZCH exhibited blue fluorescence with an absolute quantum yield of 5.1%, enabling selective and efficient detection of TC with a low limit of detection of 0.09 μg/L. Furthermore, the mechanism underlying the adsorption and detection of TC by CZCH was elucidated. Cost analysis confirmed that CZCH had a significantly lower cost of CNY 0.07 per gram of TC removal compared to activated carbon, which costs CNY 5.74. Thus, this study presents a sustainable approach for synthesizing a low-cost and multifunctional adsorbent that can be employed for the adsorption and detection of antibiotics.
摘要：
A quasi-Newton method called the direct Broyden method is considered in this paper, which satisfies the least change principle and the direct tangent condition. The direct Broyden method can ensure that the quasi-Newton matrix equals the Jacobian matrix along step direction and accumulates more derivative information of the function. Moreover, we present an accelerated version of the new method and prove its global and superlinear convergence. Extensive numerical results are reported to show the efficiency of the two methods.
作者机构：
[Qian, Shengyou; Xu, Jiao; Jiang, Leyong; Qian, SY; Jiang, LY] Hunan Normal Univ, Sch Phys & Elect, Changsha 410081, Peoples R China.;[Peng, Yuxiang] Cent South Univ Forestry & Technol, Inst Math & Phys, Changsha 410004, Peoples R China.
通讯机构：
[Qian, SY; Jiang, LY ] H;Hunan Normal Univ, Sch Phys & Elect, Changsha 410081, Peoples R China.
关键词：
all-optical switching;graphene;black phosphorus;transition metal dichalcogenide;layered material heterostructures
摘要：
Microstructured all-optical switching, possessing the unique function of light controlling light, is an important part of the on-chip ultra-fast optical connectivity network and integrated logic computing chip. Microstructured all-optical switching has attracted extensive research interest, the latest great developments of which have also yielded progress in nanophotonics, nonlinear optics, optical communications, and integrated optics, etc. The emergence of two-dimensional materials with good third-order optical nonlinearity provides an important driving force for the improvement of all-optical switches. This paper reviews the implementation principles, novel configurations, improved performance indexes, and research progress based on different two-dimensional materials for micro/nano all-optical switching. Not only is a systematic discussion of the current state provided, but also, a brief outlook is afforded on the remaining challenges in the pursuit of the application of practical on-chip microstructured all-optical switching that is based on two-dimensional materials.
期刊：
Chemical Engineering Journal,2023年456:141104 ISSN：1385-8947
通讯作者：
Guo, Xin(guocumt@163.com)
作者机构：
[Xu, Dong] Cent South Univ Forestry & Technol, Coll Food Sci & Engn, Changsha 410004, Peoples R China.;[Huang, Yong] Nanjing Forestry Univ, Coll Mat Sci & Engn, Joint Int Res Lab Biomass Energy & Mat, Nanjing 210037, Peoples R China.;[Ma, Qiang; Guo, Xin] Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Peoples R China.;[Qiao, Jianzheng; Wu, Yiqiang] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Peoples R China.
通讯机构：
[Xin Guo; Yiqiang Wu] C;College of Science, Central South University of Forestry and Technology, Changsha 410004, China<&wdkj&>College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha 410004, China
摘要：
A novel polyacrylic acid/carboxylated nanocellulose fiber/polyethylene glycol hydrogel loaded with nano-ZnO (ZnO-PAA/CNF/PEG: GH-2 (wt(ZnO)% = 12% and wt(PEG)% = 16%)) was synthesized to remove Cr(VI) from wastewater by adsorption synergistic photocatalytic reduction. The effects of ZnO content, PEG content and pH on the removal efficiency of Cr(VI) were investigated. The removal performance and mechanism of Cr(VI) by hydrogels were systematically studied by various techniques. The results showed that when the initial pH = 2, the initial concentration of Cr(VI) = 20 mg/L, the hydrogel dose = 0.5 g/L, and Irradiation power of mercury lamp was 500 W, the removal efficiency of Cr(VI) was 97.22% (dark adsorption for 60 min and photocatalysis for 50 min). The addition of PEG greatly reduced the agglomeration of nano-ZnO in GH-2 and facilitated the separation of photogenerated electron-hole pairs. The adsorption process of Cr(VI) by GH-2 accords with pseudo-second-order kinetics. The photocatalytic process conforms to the pseudo-first-order reaction kinetics. Under the optimal experimental conditions, the removal efficiency of Cr(VI) by GH-2 was still as high as 87.99% after 5 cycles. The removal mechanism of Cr(VI) was mainly through electrostatic attraction, chemical adsorption and photocatalytic reduction. This study provides a feasible method for the synthesis of hydrogel materials with excellent adsorption synergistic photocatalytic performance for the treatment of Cr(VI)-containing wastewater.
作者机构：
[Li, Zhaoshuang; Qu, Limin; Zhou, Jun; Shang, Yaxuan; Yang, Yanhong; Li, Xiangzhou; Zhou, Peng; Zheng, Min] Cent South Univ Forestry & Technol, Coll Mat Sci & Engn, Changsha 410004, Hunan, Peoples R China.;[Li, Xiangzhou] Cent South Univ Forestry & Technol, Inst Nat Prod Res & Dev, Changsha 410004, Hunan, Peoples R China.;[Zheng, Min] Hunan First Normal Univ, Sch Phys & Chem, Changsha 410205, Hunan, Peoples R China.;[Wang, Wenlei] Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.
通讯机构：
[Xiangzhou Li] C;College of Materials Science and Engineering, Central South University of Forestry and Technology, Changsha, Hunan 410004, People’s Republic of China<&wdkj&>Institute of Natural Products Research and Development, Central South University of Forestry and Technology, Changsha, Hunan 410004, People’s Republic of China
通讯机构：
[Ting Deng] I;[Jishan Li] S;State Key Laboratory of Chemo/Bio-Sensing and Chemometrics, College of Chemistry and Chemical Engineering, Hunan University, Changsha, 410082, PR China<&wdkj&>Institute of Applied Chemistry, School of Science, Central South University of Forestry and Technology, Changsha, 410004, PR China
摘要：
Pathogenic bacteria are a major cause of foodborne diseases, which not only seriously threaten human safety but also cause significant losses for the national economy. Therefore, it is very important and urgent to develop a method for the detection of pathogenic bacteria with high accuracy, high sensitivity, and easy interpretation for use in food safety and medical hygiene. Herein, based upon the sensitive color changes induced by the dispersion and aggregation states of gold nanoparticles (AuNPs), a point-of-care (POCT) colorimetric assay was constructed for the rapid and sensitive visual detection of pathogenic bacteria. The POCT visual sensing system is composed of two individual elements: (1) an alkaline phosphatase/graphene oxide (GO@PEI-ALP) nanoconjugate that can release free ALP molecules in the presence of pathogenic bacteria; (2) D-glucose-6-phosphate (pGlu) and 3-ami-nobenzene boric acid (AMBA)-functionalized AuNPs (pGlu/AMBA-AuNPs) that are cross-linked upon the digestion of pGlu by free ALP molecules, resulting in a significant color change. Under optimized conditions, the detection limit of this sensing system for target bacteria was as low as 24 CFU mL-1 and was successfully applied to complex real samples. This proposed rapid colorimetric assay has high sensitivity, accuracy, and practicability with an intuitive signal and is expected to provide new inspiration for the detection of pathogenic bacteria. <comment>Superscript/Subscript Available</comment
作者：
Tang, Jianfeng;Luo, Qiongqiong;Zeng, Dewen;Zhang, Ning
期刊：
JOURNAL OF PHYSICAL CHEMISTRY B,2022年126(7):1566-1578 ISSN：1520-6106
通讯作者：
Zhang, N
作者机构：
[Tang, Jianfeng; Zhang, Ning] Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.;[Luo, Qiongqiong; Zeng, Dewen] Cent South Univ, Coll Chem & Chem Engn, Changsha 410083, Hunan, Peoples R China.
通讯机构：
[Zhang, N ] C;Cent South Univ Forestry & Technol, Coll Sci, Changsha 410004, Hunan, Peoples R China.
摘要：
The thermodynamic and kinetic behaviors of Mg(2+)-F(-) ion pairing in aqueous solution are investigated theoretically and experimentally and are contrasted to those of Ca(2+)-F(-). Thermodynamically, similar to CaF(x)(H(2)O)(14)(2-x) (x = 1 and 2), MgF(H(2)O)(y)(+) (y = 14-20) contact ion pairs (CIPs) are more stable than their solvent-shared ion pairs (SSIPs), whereas the CIPs and SSIPs of MF(2)(H(2)O)(y) are almost isoenergetic. However, in kinetics, the conversion of SSIPs to CIPs for M(2+)-F(-) (M = Mg(2+) and Ca(2+)) ion pairing must overcome a high energy barrier due to the strong hydration of Mg(2+) and F(-). The kinetics dominate after the thermodynamics and kinetics are balanced, which hinders the formation of M(2+)-F(-) CIPs in practical MF(2) aqueous solutions (less than or equal to saturated concentrations). This result is also supported by the (19)F nuclear magnetic resonance spectra of saturated MF(2) solutions. Although the interaction between Mg(2+) and F(-) is slightly stronger than that between Ca(2+) and F(-) due to the smaller radius of Mg(2+), the formation of Mg(2+)-F(-) CIPs needs to go through two rate-limiting steps, the dehydration and entrance of F(-) (i.e., via exchange mode) with a higher energy barrier, due to the ability of strongly bound water molecules and rigorous octahedral coordinated configuration of Mg(2+), while the formation of Ca(2+)-F(-) CIPs only goes through a single rate-limiting step, the entrance of F(-) (i.e., via swinging mode) with a lower energy barrier, due to the flexible coordination configuration of Ca(2+). This is responsible for precipitation in MgF(2) aqueous solution requiring a larger supersaturation degree and a lower precipitation rate than in CaF(2). These kinetic factors lead to the association constants previously reported for MF(+) determined by a fluoride ion-selective electrode (ISE) combined with the titration method, where the MF(2) solutions were always unsaturated at the titration end point, which actually corresponds to those of the ligand process going from completely free M(2+) and F(-) to their SSIPs. A possible strategy to accurately determine the association constants of MF(+) and MF(2)(aq) CIPs by fluoride ISEs is proposed. The present results suggest that judging the formation of M(2+)-F(-) CIPs in practical solutions from a theoretical calculation perspective requires significant consideration of the kinetic factors, except for the thermodynamic factors.
