In this study, a novel lanthanide-doped nanoprobe for monitoring dipicolinic acid (DPA), a unique biomarker of Bacillus anthracis, was constructed by coordination of Tb3+ with l-histidine (His) ...functionalized ZIF-8 (His@ZIF-8). After being functionalized with His, the resultant His@ZIF-8 had abundant carboxyl and amino groups, which like tongs help His@ZIF-8 “grasp” Tb3+ firmly to form a stable lanthanide-doped nanoparticle (His@ZIF-8/Tb3+). Owing to the unsaturated coordination of Tb3+ with the amino acid group, the resultant His@ZIF-8/Tb3+ showed reserved response sites of Tb3+ to DPA because of its unique molecular structure. After the His@ZIF-8/Tb3+ coordination with DPA, the intrinsic fluorescence emission of the Tb3+ ions was triggered through energy transfer, leading to bright yellow green luminescence owing to the antenna role of DPA. Benefitting from the His functionalization and the characteristics of ZIF-8, especially the high porosity and large surface area, the developed His@ZIF-8/Tb3+ sensing platform exhibited attractive features as a fluorescent sensor for monitoring DPA such as fast response kinetics (10 s), high sensitivity and selectivity, and being portable, easy to operate, economical and secure. This sensor platform showed a satisfactory linear relationship (R2 = 0.999) ranging from 0.08 to 10 μmol L−1 and an ultralow limit of detection (LOD) of 0.02 μmol L−1. This strategy for the design of functionalized MOFs to construct sensing probes and the resultant His@ZIF-8/Tb3+ would provide a potential strategy for the exploitation of other functionalized materials used in other research fields and promising fluorescence platforms for the detection of other targets.
Three different dimensional Ni(II) coordination polymers, Ni(3-pna)(HIP)(H
2
O)
3
·H
2
O(
1
), Ni(3-pna)· (1,3,5-HBTC)(
2
) and Ni
2
(H
2
O)(3-pna)2(1,4-CHDC)
2
4
(
3
)(3-pna=3-pyridylnicotinamide, ...H
2
HIP=5-hydroxyisophthalic acid, 1,3,5-H
3
BTC=1,3,5-benzenetricarboxylic acid, 1,4-H
2
CHDC=1,4-cyclohexanedicarboxylic acid), were synthesized under hydrothermal conditions and characterized by means of infrared spectra(IR), thermal gravimetric (TG) analyses, powder X-ray diffraction(PXRD) and single-crystal X-ray diffraction. Complex
1
has a structure of 1D single-stranded chain, which is further stretched by hydrogen-bond interactions to form a 2D supramolecular sheet. Complex
2
shows a 2D network, which is stretched to 3D supramolecular frameworks through hydrogen-bond interactions. Complex 3 reveals a 3D skeleton with a (3,3,6,6)-connected {3·7
2
}{3
2
·4}{3
3
·4
2
·5·7
3
·8
5
·9}{3
3
·4
5
·5
2
·7
2
·8
2
·9} topology. The effects of different polycarboxylates on the ultimate architectures of the complexes
1
—
3
were discussed. Furthermore, the fluorescent and photocatalytic properties of the title complexes were also investigated.
Based on revisiting the RYY+Identitybased(ID-Based) key agreement protocol, we find it’s vulnerable to Intermediate results leakage(IRL) and Keycompromise impersonation(KCI) attack. A novel protocol ...called RYY++is proposed to make up for its deficiencies.Our protocol follows the Full dual exponential challenge response(FDCR-1) scheme to ensure the signature change every time, so the master public key of Private key generator(PKG) joined in signature generation can guarantee two parties trust each other. The RYY++protocol is also proven to be secure in the Strengthened extended Canetti–Krawczyk(Se CK) model which provides better support for adversary’s query and has an advantage over most existing protocols on security and efficiency.
Transmission adequacy of power system has been challenged by high investment of new line construction and limit line-corridor space. In this paper, a novel solution to increase transmission capacity ...by altering HVAC lines into fractional frequency transmission system (FFTS) is proposed. FFTS is a transmission that utilizes a relatively low grid frequency, e.g., 50/3 Hz, to extend the transmission capacity of ac lines. The proposed solution can minimize the construction efforts since the existing HVAC transmission lines can be directly employed by FFTS without any change. The structure and principle of FFTS for transmission line conversion (TLC) are introduced firstly. Then, performance of conventional ac equipment in FFTS is evaluated and comparison with respective counterpart in HVDC is carried out. Next, the economic performance of FFTS for transmission capacity upgrade is conducted based on a typical benchmark, and sensitivity analysis results are presented to determine the economic zone of FFTS. The results show that the uniform annual value (UAV) of TLC into FFTS is 24.9% and 31.6% cheaper than TLC into HVDC and constructing new HVAC lines, respectively. Therefore, FFTS is a superior scheme for transmission capacity boost.
A sulfur/graphene composite is prepared by loading elemental sulfur into three-dimensional graphene (3D graphene), which is assembled using a metal ions assisted hydrothermal method. When used as ...cathode materials for lithium–sulfur (Li–S) batteries, the sulfur/graphene composite (S@3D-graphene) with 73 wt % sulfur shows a significantly enhanced cycling performance (>700 mAh g−1 after 100 cycles at 0.1C rate with a Coulombic efficiency > 96%) as well as high rate capability with a capacity up to 500 mAh g−1 at 2C rate (3.35 A g−1). The superior electrochemical performance could be attributed to the highly porous structure of three-dimensional graphene that not only enables stable and continue pathway for rapid electron and ion transportation, but also restrain soluble polysulfides and suppress the “shuttle effect”. Moreover, the robust structure of 3D graphene can keep cathode integrity and accommodate the volume change during high-rate charge/discharge processes, making it a promising candidate as cathode for high performance Li–S batteries.
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•Three-dimensional graphene is assembled by a simple hydrothermal reduction.•The 3D graphene shows a hierarchical porous morphology and robust structure.•Sulfur content up to 73% is loaded in 3D graphene.•The composite shows high specific capacity and stable capacity retention.•The unique 3D structure enables high-rate capability.
We study machine scheduling problems in which the jobs belong to different job classes and they need to be delivered to customers after processing. A setup time is required for a job if it is the ...first job to be processed on a machine or its processing on a machine follows a job that belongs to another class. Processed jobs are delivered in batches to their respective customers. The batch size is limited by the capacity of the delivery vehicles and each shipment incurs a transport cost and takes a fixed amount of time. The objective is to minimize the weighted sum of the last arrival time of jobs to customers and the delivery (transportation) cost. For the problem of processing jobs on a single machine and delivering them to multiple customers, we develop a dynamic programming algorithm to solve the problem optimally. For the problem of processing jobs on parallel machines and delivering them to a single customer, we propose a heuristic and analyze its performance bound.
Tailored construction of advanced carbon hosts is playing a great role in the development of high‐performance lithium–sulfur batteries (LSBs). Herein, a novel N,P‐codoped trichoderma spore carbon ...(TSC) with a bowl structure, prepared by a “trichoderma bioreactor” and annealing process is reported. Moreover, TSC shows excellent compatibility with conductive niobium carbide (NbC), which is in situ implanted into the TSC matrix in the form of nanoparticles forming a highly porous TSC/NbC host. Importantly, NbC plays a dual role in TSC for not only pore formation but also enhancement of conductivity. Excitingly, the sulfur can be well accommodated in the TSC/NbC host forming a high‐performance TSC/NbC‐S cathode, which exhibits greatly enhanced rate performance (810 mAh g−1 at 5 C) and long cycling life (937.9 mAh g−1 at 0.1 C after 500 cycles), superior to TSC‐S and other carbon/S counterparts due to the larger porosity, higher conductivity, and better synergetic trapping effect for the soluble polysulfide intermediate. The synergetic work of porous the conductive architecture, heterodoped N&P polar sites in TSC and polar conductive NbC provides new opportunities for enhancing physisorption and chemisorption of polysulfides leading to higher capacity and better rate capability.
A novel hybrid host consisting of a N,P‐codoped trichoderma spore carbon (TSC) matrix and a conductive NbC adsorbent for sulfur cathodes is proposed. The designed TSC/NbC‐S electrode displays extraordinary performance with superior rate capability (810 mAh g−1 at 5 C) and ultrastable cycling life (937.9 mAh g−1 at 0.1 C after 500 cycles).
Si/C composites are currently the most commercially viable next-generation lithium-ion battery anode materials due to their high specific capacity. However, there are still many obstacles need to be ...overcome such as short cycle life and poor conductivity. In this work, we design and successfully synthesis an excellent durable double-conductive core-shell structure p-Si-Ag/C composites. Interestingly, this well-designed structure offers remarkable conductivity (both internal and external) due to the introduction of silver particles and carbon layer. The carbon layer acts as a protective layer to maintain the integrity of the structure as well as avoids the direct contact of silicon with electrolyte. As a result, the durable double-conductive core-shell structure p-Si-Ag/C composites exhibit outstanding cycling stability of roughly 1000 mAh g−1 after 200 cycles at a current density of 0.2 A g−1 and retain 765 mAh g−1 even at a high current density of 2 A g−1, indicating a great improvement in electrochemical performance compared with traditional silicon electrode. Our research results provide a novel pathway for production of high-performance Si-based anodes to extending the cycle life and specific capacity of commercial lithium ion batteries.
•The etching of Al-Si alloy constructs a stable internal 3D skeleton.•Ag particles synthesized in situ improve the internal conductivity of composites.•The carbon layer stabilizes the structure and increases external conductivity.
Electrocatalytic conversion of CO2 to syngas is an attractive pathway for transforming CO2 into high-value chemicals, but the process still suffers from low selectivity. In our work, we construct a ...two-dimensional (2D) structure of Cu2Se-SnO heterojunction catalyst through a high-temperature thermal reduction method. The catalyst with two phases located in the same plane exhibits efficient charge transfer, and the tunable heterojunction interface acts as active sites for CO2 adsorption and activation. Additionally, its suitable *CO adsorption energy facilitates the desorption of intermediates, leading to the formation of CO. Finally, this catalyst demonstrates excellent selectivity for syngas, maintaining a Faradaic efficiency (FE) of over 60% across a wide range of potentials (-0.67 ∼ −1.07 V vs. RHE) with adjustable syngas ratios and up to 92% FE at −0.97 V vs. RHE. This research provides a new approach for balancing reduction CO2 and competing hydrogen evolution reaction.
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•Cu2Se-SnO nanosheet heterojunction with two phases locates in the same plane.•The tunable heterojunction interface acts as active sites for CO2 reduction.•The in-plane heterojunction can avoid the shielding of the interface.•The introduction of SnO can decrease the adsorption strength of *CO on Cu2Se.•This catalyst demonstrates excellent selectivity for syngas with a FE over 60%.
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