关键词：
Julia sets;buried component;singular perturbations
摘要：
Let f be a rational map with degree d\geq 2 whose Julia set is connected but not equal to the whole Riemann sphere. It is proved that there exists a rational map g such that g contains a buried Julia component on which the dynamics is quasiconformally conjugate to that of f on the Julia set if and only if f does not have parabolic basins and Siegel disks. If such g exists, then the degree can be chosen such that \deg (g)\leq 7d-2. In particular, if f is a polynomial, then g can be chosen such that \deg (g)\leq 4d+4. Moreover, some quartic and cubic rational maps whose Julia sets contain buried Jordan curves are also constructed.
关键词：
zinc-bromine battery;high voltage;high energy density;K+-conducting membrane;hybrid electrolytes
摘要：
The zinc-bromine redox flow battery (ZBB) is an ideal device of energy storage systems. Nevertheless, its energy density is relatively low compared to those of Li-ion batteries, due to its low output voltage. Herein, a high-voltage aqueous hybrid zinc-bromine battery system (AHZBBs) was developed, where K+-conducting membrane was used to segregate neutral-alkaline hybrid electrolytes and redox couples of Br-2/Br(-)and [Zn(OH)(4)](2-)/Zn at the positive and negative electrode. Benefited from an efficient and stable cathode catalyst (carbon-manganite nanoflakes), this AHZBB delivered a high average output voltage of 2.15 V and energy density of 276.7 Wh/kg without capacity attenuation after 200 cycles. More importantly, this work provides an efficient avenue to elevating the output voltage and energy density, and will strongly encourage studies on redox flow batteries.
摘要：
The microjetting processes of single-crystal fin with sinusoidal surface defects under laser loading and plane impact loading are investigated by using molecular dynamics simulations via the second nearest-neighbor modified embedded atom method potential. Simulation results exhibit that the jetting factors for laser loading and plane impact loading first increase with the increment of shock breakout pressure and then reach their own saturation values, in agreement with previous experimental observations. However, the jetting factor under laser loading saturates at relatively lower shock breakout pressure than its counterpart under plane impact loading. Structure analysis via x-ray diffraction and radial distribution function techniques indicates that the laser loading leads to higher melting degree, which further facilitates the ejection process. The spike velocity linearly depends on the shock breakout pressure for both loading methods, but the bubble velocity varies with the loading method. In addition, void nucleation and growth within the sample are observed for laser loading due to the interaction of release waves. The simulation results reveal the underlying mechanisms of ejection process under plane impact loading and laser loading, helping enhance the understanding of microjetting phenomena.
作者机构：
[Mai, Yaohua; Qiu, Shudi; He, Wenxin; Guo, Fei; Mai, YH; Guo, F; Hu, Jinlong] Jinan Univ, Coll Informat Sci & Technol, Inst New Energy Technol, Guangzhou 510632, Guangdong, Peoples R China.;[Peng, Chang; You, Jiang] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Liu, Xianhu; Li, Chaohui] Zhengzhou Univ, Natl Engn Res Ctr Adv Polymer Proc Technol, Zhengzhou 450002, Henan, Peoples R China.
通讯机构：
[Mai, YH; Guo, F] J;[Peng, Chang] H;Jinan Univ, Coll Informat Sci & Technol, Inst New Energy Technol, Guangzhou 510632, Guangdong, Peoples R China.;Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.
关键词：
energy-level alignments;hole-transport materials;inverted solar cells;polyfluorene copolymers
摘要：
Inverted perovskite solar cells (PSCs) that can be entirely processed at low temperatures have attracted growing attention due to their cost-effective production. Hole-transport materials (HTMs) play an essential role in achieving efficient inverted PSCs, as they determine the effectiveness of charge extraction and recombination at interfaces. Herein, three polyfluorene copolymers (TFB, PFB, and PFO) are investigated as HTMs for construction of inverted PSCs. It is found that the photovoltaic performance of the solar cells is closely correlated with the electronic properties of the HTMs. Due to its high mobility along with the favored energy-level alignment with perovskite, TFB shows superior charge extraction and suppressed interfacial recombination than PFB- and PFO-based devices, which delivers a high efficiency of 18.48% with an open-circuit voltage (V-OC) of up to 1.1 V. In contrast, the presence of a large energy barrier in the PFO-based devices results in substantial losses in both V-OC and photocurrent. These results demonstrate that TFB can serve as a superior HTM for inverted PSCs. Moreover, it is anticipated that the performance of the three HTMs identified here might guide the molecular design of novel HTMs for the manufacture of highly efficient inverted PSCs.
期刊：
European Journal of Medicinal Chemistry,2020年189:112028 ISSN：0223-5234
通讯作者：
Wang, LingLi;Zhou, Wen
作者机构：
[Zhou, Li] Hunan Agr Univ, Coll Sci, Furong Rd, Changsha 410128, Peoples R China.;[Chen, Wenming] Hunan Univ Chinese Med, Affiliated Hosp 1, Dept Pharmaceut, Prod Ctr, 95 Shaoshan Rd, Changsha 41007, Hunan, Peoples R China.;[Hu, Jiliang; Zhou, Wen; Cao, Chenyang; Ye, Wenchong; Wang, LingLi] Guangzhou Univ Chinese Med, Sch Pharmaceut Sci, E 232,Waihuan Rd, Guangzhou 510006, Peoples R China.;[Shi, Yonghui] Sun Yat Sen Univ, Sun Yat Sen Mem Hosp, Dept Pharm, Guangzhou 510120, Guangdong, Peoples R China.
通讯机构：
[Wang, LL; Zhou, W] G;Guangzhou Univ Chinese Med, Sch Pharmaceut Sci, E 232,Waihuan Rd, Guangzhou 510006, Peoples R China.
关键词：
CYP1B1;Click reaction;PROTACs;Reversal of drug resistance;alpha-Naphthoflavone-based conjugates
摘要：
Extrahepatic cytochrome P450 161 (CYP1B1), which is highly expressed in various tumors, is an attractive and potential target for cancer prevention, therapy, and reversal of drug resistance. CYP1B1 inhibition is the current predominant therapeutic paradigm to treating CYP1B1-mediated malignancy, but therapeutic effect has little success. Herein, we reported CYP1B1 degradation in place of CYP1BI inhibition for reversing drug resistance toward docetaxel in CYP1B1-overexpressing prostate cancer cell line DU145 using a PROTAC strategy. Replacing chlorine atom of a CYP1B1 selective inhibitor we found previously with ethynyl, we got the resulting alpha-naphthoflavone derivative 5 which kept strong inhibition against CYP1B1 (IC50 = 0.4 +/- 0.2 nM) and high selectivity. Coupling of 5 with thalidomide derivatives of varying chain lengths afforded conjugates 6A-D via click reaction. In vitro cell-based assay indicated that 6C was more effective in eliminating drug resistance of CYP1B1-overexpressed DU145 cells compared with other analogues. Western blotting analysis showed CYP1B1 degradation was one main reason for the reversal of drug resistance to docetaxel and the effect was obtained in a concentration-dependent manner. This work is the first attempt to overcome CYP1B1-mediated drug resistance via CYP1B1 degradation instead of CYP1B1 inhibition, which could provide a new direction toward eliminating drug resistance. (C) 2020 Elsevier Masson SAS. All rights reserved.
作者机构：
[Hu, Renzong; Zhu, Min; Wen, Gang; Liang, Tao; Tan, Liang; Liu, Jun] South China Univ Technol, Sch Mat Sci & Engn, Guangdong Prov Key Lab Adv Energy Storage Mat, Guangzhou 510640, Peoples R China.;[Liu, Hui] Hunan Agr Univ, Coll Sci, Changsha 410128, Hunan, Peoples R China.;[Zhang, Yao; Ouyang, Yunpeng] Sunwoda Elect Co Ltd, SUNWODA SCUT Joint Lab Adv Energy Storage Technol, Shenzhen 518107, Peoples R China.
通讯机构：
[Hu, Renzong] S;South China Univ Technol, Sch Mat Sci & Engn, Guangdong Prov Key Lab Adv Energy Storage Mat, Guangzhou 510640, Peoples R China.
关键词：
Full cell performance;Tin oxide;Anode materials;Coulombic efficiency
摘要：
Despite there being many reports on SnO2-based anode materials, most of the electrode materials are tested in half cells using lithium metal with unlimited lithium-ion sources as the counter electrode, which may conceal the real properties of these composites to a certain extent. In this study, a ternary SnO2-Co-C composite was fabricated by a scalable ball milling strategy. The composite exhibited high initial Coulombic efficiency (ICE, > 80%), a large capacity (similar to 900 mA h g(-1)) and superior cycling stability (capacity retention more than 99% after 100 cycles) in half cells. Furthermore, coin-type full cells in which the ternary SnO2 -Co-C anodes were paired with different cathodes were demonstrated. A LiFePO4 vertical bar vertical bar SnO2-Co-C full cell tested at 0.5-3.4 V exhibited an ICE of 75.1% and an initial discharge capacity of 906 mA h g(-1), which were close to those of the SnO2-Co-CIILi half cells. By analyzing the cycling performance and characteristics of the charge/discharge process for the full cells with different capacity ratios of cathode/anode, it was confirmed that the capacity decay of the full cells was due to the continuous consumption of Li+ ions during cycling. Hence, the testing voltage windows were adjusted according to the lithiation/de-lithiation behavior of the SnO2. On this basis, the LiFePO4 vertical bar vertical bar SnO2-Co-C full cells tested at 2.3-3.4 V and the LiCoO2 vertical bar vertical bar SnO2-Co-C full cells tested at 2.60-3.75 V exhibited excellent cycling stability, demonstrating 80.3% and almost 100% capacity retention after 100 cycles, respectively, thereby laying a foundation for the practical application of advanced SnO2-based anodes in lithium-ion batteries. (C) 2020 Elsevier Ltd. All rights reserved.
摘要：
With the development of the removal of organic pollutants in the soil and water environment, antibiotics have been considered as emerging pollutants and received considerable attention among the scientific community. Thus, there is a need for an effective, economical, fast, operational feasible and environmental-friendly technology to remove antibiotics. Adsorption technology would be one of the most promising option on the basis that it best meets the criteria we set out above. From the most primitive activated carbon to the most innovative modified biochar, carbon-based materials have played a significant role in the adsorption process of antibiotics all the time. This paper reviews the adsorption behavior of some representative antibiotics (e.g., chloramphenicols, sulfonamides, tetracyclines, flouroquinolones) over various carbonaceous materials (i.e., activated carbon, carbon nanotubes, graphene, and biochar). Nevertheless, in addition to the structural characteristics and adsorption capacities of carbon-based materials, a special emphasis was placed on the underlying adsorption mechanisms and roles of different influencing factors in the adsorption process. Moreover, the knowledge gaps and research challenges have been highlighted, including design and optimization of the carbonaceous materials for antibiotics adsorption.
通讯机构：
[Cai, Changqun] X;Xiangtan Univ, Coll Chem, Key Lab Green Organ Synth & Applicat Hunan Prov, Key Lab Environmentally Friendly Chem & Applicat, Xiangtan 411105, Peoples R China.
关键词：
G-wire;Label-free;Enzyme-free;Cell lysates
摘要：
An enzyme-free resonance light scattering (RLS) method is described for the determination of microRNA-122. A guanine nanowire (G-wire) is used that consists of a predesigned DNA1 and a G-quadruplex sequence DNA2. These hybridize with microRNA-122 and partially hybridize with DNA2. After formation of stable double strands with DNA1, DNA2 is released. On addition of K+ and Mg2+ ions, the G-quadruplex sequences undergo self-assembly to form long filamentous G-wires. This increases the intensity of RLS. A 6.1 pM detection limit was obtained, and the linear response covers the 50 pM to 300 nM microRNA concentration range. The method was successfully applied to the quantitation of microRNA-122 in hepatocellular carcinoma cell lysates. Conceivably, this assay can be extended to other RLS methods for biomarker detection by simply changing the sequence of DNA1.
摘要：
Tungsten oxide (WO3) as electrode material has the drawbacks including poor rate capability and low capacitance. We firstly report a facile strategy to prepare WO3/MXene composite by intimately electrostatic attraction between the positively charged WO3 nanorods (WNRs) and the negatively charged transition metal carbides (MXene). This type composite shows higher specific capacitance (297 F g(-1)) compared with pure WNRs (121 F g(-1)) at a current density of 1 A g(-1) in 0.5 MH2SO4 aqueous electrolyte. In addition, the as-prepared composite electrode displays good retention rate (82.2% retention at 5 A g(-1)) and cyclic stability (73.4% even after 5000 cycles at 4 A g(-1)). The attractive electrochemical performance of WNRs/MXene may be attributed to the main reasons as follows: The MXene acts as electrons collector effectively improving the electrical conductivity and supplying more electrons to participate redox reactions happened on the surface and interior of WNRs; The electrostatic self-assembly improves the stability of WNRs/MXene. (C) 2019 Elsevier B.V. All rights reserved.
摘要：
In this paper, a series of novel orange-red emission phosphors Sr8ZnY(PO4)(7):Sm3+ (SZYP:Sm3+) were synthesized by high-temperature solid-state reaction. The photoluminescence and concentration-dependent properties of this phosphor were investigated carefully through diffuse reflection spectra, excitation and emission spectra, Commission Internationale de l'Eclairage (CIE) chromaticity coordinate and decay times. SZYP:Sm3+ could be efficiently excited by n-UV and blue lights which center at 318, 345, 363, 376, 401, 410, 440 and 475 nm, respectively. The characteristic orange-red emission peaking at 563, 601 and 647 nm had been detected, which should be attributed to the characteristic f-f forbidden transition of Sm3+. The internal quantum efficiency (IQE) of ideal phosphor of SZYP:0.09Sm(3+) reached as high as 47%. In addition, The concentration quenching mechanism and thermal stability of SZYP:Sm3+ were further investigated. It was found SZYP:Sm3+ can maintain 93% of initial emission intensity at 150 degrees C and the corresponding activation energy was calculated to be 0.26 eV based on Arrhenius formula. The emission intensity of 1.0Mg(2+) and 0.02Al(3+) incorporated SZYP:0.09Sm(3+) reached up to 134% and 117% of the initial value, respectively. Moreover, (light-emitting diodes) LED devices were fabricated by employing the optimized samples as orange-red component with 365 nm n-UV chips. The desired emission in plant absorption region and extremely high thermal stability imply that SZYP:Sm3+ is suitable for the application in plant growth LED lighting. (C) 2019 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.
关键词：
Breather;discrete nonlinear Schrodinger equation;subquadratic;critical point
摘要：
In this article we study discrete nonlinear Schrodinger equations without periodicity assumptions. We show the existence of multiple solutions of the form u(n)e(-iwt) (called breathers) by using Clark's Theorem in critical point theory.
摘要：
The 2D transition metal carbide (MXene) is a new type of promising material for energy storage due to its metallic conductivity and highly active surface. This paper describes a new photo -responsive Azo-MXene hybrid that is fabricated through electrostatic interactions between the negatively charged MXene and the cationic Azo-surfactants. After performing systematical characterizations, we found a strong electrostatic interaction force between the MXene and Azo-surfactants in this hybrid and a uniform distribution of Azo groups in the MXene structure. Notably, this Azo-MXene hybrid can self-assemble to an aggregated structure due to the hydro-phobization of Azo on the surface of MXene. Furthermore, the self-assembly of this hybrid can be modulated by ultraviolet light irradiation. This process of transition is also responsible for the hybrid's electrochemical performance upon ultraviolet light irradiation, which may be applied as a photo -responsive conductive material for photo-energy conversion and storage devices.
