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•The development of carbon materials in the electrocatalytic oxidative degradation of wastewater in recent years is reviewed.•The characteristics of carbon materials and optimization ...ideas were discussed.•The preparation process of carbon-based material electrode is introduced systematically.•Mechanisms of carbon-based material electrode in the electroabsorption and electrocatalysis were discussed in detail.•Research directions and foreseeable challenges in the electrocatalytic degradation of carbon-based electrodes are summarized and prospected.
Carbon materials are widely used as catalysts in electrocatalytic oxidative (EO) degradation of wastewater due to their large specific surface area and low cost. Carbon materials can also be used as catalyst carriers for EO reactions due to their ease of functionalization with other heteroatoms and metals/metal oxides. To improve the catalytic activity and current efficiency of carbon materials, modifying the structural and physicochemical properties of conventional carbon materials are common improvement method. This review briefly outlines the recent research progress of carbon materials in EO for organic pollutants degradation. It also discusses the modification strategies and corresponding electrocatalytic properties of various carbon materials (carbon nanomaterials and porous carbon materials), and explores the EO mechanism. Finally, some summaries of the remaining challenges and future developments of carbon materials in the field of electrocatalysis are given.
Graphene oxide flexibly supported MoO2 porous architectures (MoO2/GO) by decomposition of the prepared ammonium molybdate/GO preforms is fabricated. Focused ion beam microscope analysis shows that ...the inside structures of the architectures strongly depend on the percentages of the GO used as flexible supports: micrometer scale MoO2 particulates growing on the GO (micrometer MoO2/GO), 3D honeycomb‐like nanoarchitectures (MoO2/GO nanohoneycomb), and layered MoO2/GO architectures are achieved at the percentage of GO at 4.3, 15.2, and 20.8 wt%, respectively. The lithium storage performance of the MoO2/GO architectures strongly depends on their inside structures. At the current density of 100 mA g−1, the capacities of the micrometer MoO2/GO, MoO2/GO nanohoneycomb, and layered MoO2/GO remain at 901, 1127, and 967 mAh g−1 after 100 cycles. The average coulombic efficiencies of micrometer MoO2/GO, MoO2/GO nanohoneycomb, and layered MoO2/GO electrodes are 97.6%, 99.3%, and 99.0%. Moreover, the rate performance shows even cycled at a high current density of 5000 mA g−1, the MoO2/GO nanohoneycomb can deliver the capacity as high as 461 mAh g−1. The MoO2/GO nanohoneycomb exhibits best performance attributed to its unique nanohoneycomb structure constructed with ultrafine MoO2 fixed on the GO flexible supports.
MoO2/graphene oxide (GO) architectures are achieved by decomposition of the prepared ammonium molybdate/GO preforms. The nanohoneycomb‐like nanoarchitectures are achieved at the optimized ratio with high MoO2 loading 84.8 wt%. The Li‐ion storage capability is significantly improved attributed to their unique nanohoneycomb architectures constructed with ultrafine MoO2 fixed on the GO flexible supports.
Abstract
Linear low-density polyethylene (LLDPE) is widely used in many fields like packaging and film due to its chemical resistance and high tensile strength. This review mainly introduces the ...preparations and applications of LLDPEs produced by Ziegler-Natta catalyst, metallocene-based catalyst, and late transition metal catalyst, respectively. The improved mechanical and conductivity properties of LLDPE by Ziegler-Natta catalysts, higher activity of the metallocene-based catalysts and high performance of LLDPE directly produced by late transition metal were highlighted. The enhancement of the resistance, flexibility, transparency properties, and yield is achieved using those catalysts and mild conditions. This also leads to more applications in electrical, medical, and surgical areas and can reach an industrial scale.
In this study, a simple asymmetrical double torsion pendulum is built and operated to study coupled harmonic motion. The setup, which consists of two circular inertia members suspended horizontally ...at different locations on a vertical guitar wire, has a close mechanical similarity to a wall-spring-mass-spring-mass system. The restoring torque of the twisted guitar wire drives the two inertia members to rotate in the horizontal plane. A smartphone and target-tracking software are used to measure the normal frequencies, which are found to reside in two different frequency bands separated by an obvious frequency gap. The described setup has several pedagogical advantages, including easy accessibility, good accuracy, and continuous tunability, and is thus an effective means for engaging students with topics such as mechanical similarity, moment of inertia, torque constant, normal frequency, and target tracking. Teachers can also use the setup as a simple classical analogy to interpret the mechanical shift of the vibrational frequency of a diatomic molecule adsorbed on a sample surface.
As a set of persistent organic pollutants (POPs) that cause serious harm to human and animal health, polycyclic aromatic hydrocarbons (PAHs) degradation has attracted attentions of many scholars. ...Ozonation is one of the promising techniques for removing PAHs from various aqueous solutions because of its molecular structures, rapid reaction with ozone (O
3
), and oxidation by-products of PAHs produced during ozonation are more biodegradable than initial PAHs. However, its application is constrained by the high cost of ozone production, and organic matter in water is only partially oxidized. In recent years, to improve the efficiency of the ozonation process and optimize economic efficiency, several methods of O
3
-based advanced oxidation processes (AOPs) (i.e. O
3
/UV, O
3
/H
2
O
2
, O
3
/H
2
O
2
/UV, O
3
/Fenton, O
3
/Catalyst) have been studied. These AOPs generate more HO* than molecular ozone. This review summarized recent developments relating to the degradation of PAHs via O
3
-based AOPs and their exciting mechanisms. Compared different processes characteristics in terms, such as radical species, operational conditions, by-products and their toxicity, and cost. We considered that O
3
/photocatalyst seems to be a better choice for PAHs degradation. Finally, the challenges and future trends of PAH degradation have prospected.
The biosynthesis of histidine, a proteinogenic amino acid, has been extensively studied due to its importance in bacterial growth and survival. Histidinol-phosphate phosphatase (Hol-Pase), which is ...responsible for the penultimate step of histidine biosynthesis, is generally the last enzyme to be characterized in many bacteria because its origin and evolution are more complex compared to other enzymes in histidine biosynthesis. However, none of the enzymes in histidine biosynthesis, including Hol-Pase, have been characterized in
, which is an important opportunistic Gram-negative pathogen that can cause serious human infections. In our previous work, a transposon mutant of
was found to display a growth defect on glucose-containing minimal solid medium. In this study, we found that the growth defect was due to incomplete histidine auxotrophy caused by PA0335 inactivation. Subsequently, PA0335 was shown to encode Hol-Pase, and its function and enzymatic activity were investigated using genetic and biochemical methods. In addition to PA0335, the roles of 12 other predicted genes involved in histidine biosynthesis in
were examined. Among them,
(PA3165),
(PA3152), and
(PA3151) were found to be dispensable for histidine synthesis, whereas
(PA4449),
(PA5067),
(PA5140),
(PA5143),
(PA5066),
(PA4447), and
(PA5141) were essential because deletion of each resulted in complete histidine auxotrophy; similar to the case for PA0335,
(PA5142) or
(PA4448) deletion caused incomplete histidine auxotrophy. Taken together, our results outline the histidine synthesis pathway of
Histidine is a common amino acid in proteins. Because it plays critical roles in bacterial metabolism, its biosynthetic pathway in many bacteria has been elucidated. However, the pathway remains unclear in
, an important opportunistic pathogen in clinical settings; in particular, there is scant knowledge about histidinol-phosphate phosphatase (Hol-Pase), which has a complex origin and evolution. In this study,
Hol-Pase was identified and characterized. Furthermore, the roles of all other predicted genes involved in histidine biosynthesis were examined. Our results illustrate the histidine synthesis pathway of
The knowledge obtained from this study may help in developing strategies to control
-related infections. In addition, some enzymes of the histidine synthesis pathway from
might be used as elements of histidine synthetic biology in other industrial microorganisms.
Effective detection of biomolecules is important for biological research and medical diagnosis. We here propose a ligation-triggered and protein-assisted fluorescence anisotropy amplification ...platform for sensitive and selective detection of small biomolecules in a complex biological matrix. In the proposed method, in the presence of target small molecules, FAM-labeled DNA 1 and biotin-labeled DNA2 were ligated to produce an integrated DNA. As a result, taking advantage of the extraordinary strong interaction between biotin and streptavidin, we employed a novel mass amplification strategy for sensitive detection of small molecules through fluorescence anisotropy. The method could detect ATP from 0.05 to 1 μM, with a detection limit of 41 nM, and detect NAD
+
from 0.01 to 1 μM, with a detection limit of 6.7 nM. Furthermore, ligase-specific dependence of different cofactors provides good selectivity for the detection platform. As a result, the new platform has a broad spectrum of applications both in bioanalysis and biomedical fields.
A ligation-triggered and protein-assisted fluorescence anisotropy amplification platform has been developed for sensitive and selective detection of small molecules in a biological matrix.
Abstract
Graphene oxide flexibly supported MoO
2
porous architectures (MoO
2
/GO) by decomposition of the prepared ammonium molybdate/GO preforms is fabricated. Focused ion beam microscope analysis ...shows that the inside structures of the architectures strongly depend on the percentages of the GO used as flexible supports: micrometer scale MoO
2
particulates growing on the GO (micrometer MoO
2
/GO), 3D honeycomb‐like nanoarchitectures (MoO
2
/GO nanohoneycomb), and layered MoO
2
/GO architectures are achieved at the percentage of GO at 4.3, 15.2, and 20.8 wt%, respectively. The lithium storage performance of the MoO
2
/GO architectures strongly depends on their inside structures. At the current density of 100 mA g
−1
, the capacities of the micrometer MoO
2
/GO, MoO
2
/GO nanohoneycomb, and layered MoO
2
/GO remain at 901, 1127, and 967 mAh g
−1
after 100 cycles. The average coulombic efficiencies of micrometer MoO
2
/GO, MoO
2
/GO nanohoneycomb, and layered MoO
2
/GO electrodes are 97.6%, 99.3%, and 99.0%. Moreover, the rate performance shows even cycled at a high current density of 5000 mA g
−1
, the MoO
2
/GO nanohoneycomb can deliver the capacity as high as 461 mAh g
−1
. The MoO
2
/GO nanohoneycomb exhibits best performance attributed to its unique nanohoneycomb structure constructed with ultrafine MoO
2
fixed on the GO flexible supports.
The capacitated arc routing problem with time window has been studied for years, while uncertainties in real-world scenarios, such as uncertain demands and uncertain routing conditions, were rarely ...considered. In this paper, we formulate an uncertain capacitated arc routing problem with time window that takes into account the uncertain demand of tasks, the uncertain deadheading costs and the uncertain presence of tasks and paths. A number of problem instances are generated based on the benchmark instances of static capacitated arc routing problem with time window considering the aforementioned four uncertain factors. To tackle this new challenging problem, we adapt a state-of-the-art algorithm for solving uncertain capacitated arc routing problem, an estimation of distribution algorithm (EDA) with a stochastic local search, to find robust solutions. Another algorithm, a memetic algorithm with extended neighborhood search, is also adapted as a baseline solution algorithm to this challenging problems. Our experimental results indicate that our EDA-based algorithm is effective in finding robust solutions to uncertain capacitated arc routing problems with time window.
Based on the market demand for service-oriented robot, the automatic delivery system of robot is designed in this paper. The system is controlled by ArduinoMega2560 control board, ROS (Robot ...Operating System) as the robot operating system, combined with Slam particle filter algorithm to complete the robot positioning and navigation functions. At the same time, based on the Qt software interactive platform to control the robot walking, using the steering gear to open and close the storage box, 4G module SMS notification. In summary, this paper designs an interactive platform for indoor file transfer service robot based on ROS and Slam particle filter algorithm. Through this platform, we can control file access, notify the operation of pickup, and improve the comfort of human-computer interaction.
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