Rationally designed hybrids of NiCo₂O₄ and polymeric carbon nitride as faradaic electrodes with enhanced electrochemical performance

Wang, Zhonghao,Hu, Xun,Wang, Lina,Jin, Bingjun,Zou, Guojun,Huang, Zhiwei,Liu, Qing,Hu, Guangzhi,Zhang, Kan,Park, Jong Hyeok Elsevier 2019 ELECTROCHIMICA ACTA Vol.299 No.-

<P><B>Abstract</B></P> <P>Herein, electrochemically sluggish polymeric carbon nitride (PCN) is successfully introduced into NiCo<SUB>2</SUB>O<SUB>4</SUB> to form hybrids of NiCo<SUB>2</SUB>O<SUB>4</SUB> and PCN, in which PCN nanosheets are regarded as a substrate to promote the nucleation and subsequent in-situ growth of NiCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets. The surface of as-prepared hybrids are rich in Ni and Co ions in low and high valence state, respectively. In addition, the hybrids exhibit more hydrophilic compared with that of pristine NiCo<SUB>2</SUB>O<SUB>4</SUB> due to its higher amounts of hydroxyl group. It has been found that the nitrogen species originated from PCN nanosheets tend to bond with the metal ions and electrolyte used, resulting in tuning the electronic structural states and coupling effects with NiCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets. Owing to these structural characteristics, the electrochemical performance as faradaic electrode materials and long-term stability of optimized hybrid is much superior to the bare NiCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets.</P> <P><B>Highlights</B></P> <P> <UL> <LI> NiCo<SUB>2</SUB>O<SUB>4</SUB>-PCN samples were prepared via a facile and scalable strategy. </LI> <LI> The NiCo<SUB>2</SUB>O<SUB>4</SUB>-PCN-40 exhibited much higher supercapacitor performance than that of pure NiCo<SUB>2</SUB>O<SUB>4</SUB>. </LI> <LI> The PCN nanosheets can promote the nucleation and subsequent in-situ growth of NiCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets in oriented way. </LI> <LI> The presence of PCN can tune the electronic structural states and coupling effects with NiCo<SUB>2</SUB>O<SUB>4</SUB> nanosheets. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>The vertically growth of NiCo<SUB>2</SUB>O<SUB>4</SUB> on PCN nanosheets substrate with 3D open frameworks synthesized here is beneficial for facilitating electrolyte ions transport and electron trapping, thus boosting the supercapacitor performance of NiCo<SUB>2</SUB>O<SUB>4</SUB>.</P> <P>[DISPLAY OMISSION]</P>

Static and Seismic Experimental Study of Novel Prefabricated Beam-Column Joints with Elongated-Hole Brackets

Zhang Zhiwei,Li Dong,Wang Huajie,Li Songling,Qian Hongliang,Bi Yanhua,Wang Guoxing,Jin Xiaofei,Fan Feng 한국강구조학회 2024 International Journal of Steel Structures Vol.24 No.1

To enhance the structural connectivity of prefabricated steel frame systems and augment their construction effi ciency, this study introduces an innovative prefabricated joint design tailored for square steel columns and H-beams characterized by varying beam heights. This study includes both static loading tests and seismic tests performed on full-scale joints featuring two diff erent beam heights. This investigation involved a comprehensive analysis of the static and seismic performance of the joints, employing various performance metrics such as ultimate load capacities, ultimate rotation angles, hysteresis curves, skeleton curves, stiff ness degradation curves, and ductility coeffi cients, in alignment with established structural codes and standards. The results indicate that the plasticity of the H-beam is fully developed, exhibiting a relative slip phenomenon. Additionally, the joints demonstrate commendable rotational capacity, with hysteresis curves consistently manifesting an inverse S-shape and exhibiting noteworthy stiff ness degradation. Furthermore, the comparison with the unimproved joint shows that the novel joint, in addition to being easy to construct, has better ductility and energy dissipation capacity. The results of the study will provide a technical reference for further optimization and application of prefabricated beam-column joints.

Constructing Hierarchical Porous Bacterial Cellulose Outer Layer for Enhanced SMCs Infiltration in a Double-Layered Vascular Graft

Jie Wang,Weijuan Nie,Ming Wang,Chen Zhang,Jian Li,Honglin Luo,Quanchao Zhang,Zhiwei Yang,Yizao Wan 한국섬유공학회 2023 Fibers and polymers Vol.24 No.11

Natural blood vessels possess a multi-layered structure. Herein, we present a bio-inspired double-layered integrated tubular graft with a compact inner layer and a porous outer layer. The inner layer consists of nanofibrous bacterial cellulose (BC) and microfibrous cellulose acetate (CA), which favors the adhesion and proliferation of endothelial cells (ECs). The outer layer, with hierarchical pores including nano-sized pores from pristine BC, median-sized pores (dozens of microns) created by particle leaching, and a large pore (hundreds of microns) array created by laser ablation, is appropriate for the penetration of vascular smooth muscle cells (SMCs). The in-situ biosynthesis was employed to "suture" the two layers, aiming to achieve an integrated tubular structure. The morphology, mechanical properties, and cell behavior of the tubular grafts were characterized. The in vitro study demonstrates that the unique outer layer possesses enhanced SMC penetration compared to the counterpart without hierarchical pores. Overall, the findings of this study demonstrate the potential of such a biomimetic integrated vascular graft for vascular replacement and regeneration.

Application and development of pyrolysis technology in petroleum oily sludge treatment

Ziyi Wang,Zhiqiang Gong,Zhenbo Wang,Xiaoyu Li,Zhiwei Chu 대한환경공학회 2021 Environmental Engineering Research Vol.26 No.1

With the enhancement of public awareness of environmental protection, the harm of oily sludge has gradually been paid attention to. As a kind of dangerous solid waste, the arbitrary disposal of oily sludge will cause quite serious harm to both the environment and human beings. Research on the treatment methods of oily sludge has become a hot spot recently. At present, treatment methods of oily sludge are various, mainly including pyrolysis, direct combustion, freeze-thaw treatment, biological treatment, solvent extraction, thermochemical cleaning, ultrasound-assisted treatment or joint technology, etc. Based on the consideration of economic benefits, social benefits and treatment difficulties, pyrolysis has been considered to be the most appropriate method for oily sludge treatment. Syngas, liquid oil and char can be obtained from pyrolysis of oily sludge, which can meet different needs. In this paper, the pyrolysis technology of oily sludge is reported in detail, including pyrolysis methods, operational parameters and pyrolysis products of oily sludge. On the basis, the advantages and limitations of oily sludge pyrolysis technology are discussed, together with the report of feasibility of pyrolysis technology of oily sludge. Moreover, the development trend of pyrolysis technology of oily sludge is prospected for the future work.

Oxygen Uptake Rate Controlling Strategy Balanced with Oxygen Supply for Improving Coenzyme Q10 Production by Rhodobacter sphaeroides

Ze-Jian Wang,Xingzi Zhang,Ping Wang,Zhiwei Sui,Meijin Guo,Siliang Zhang,Yingping Zhuang 한국생물공학회 2020 Biotechnology and Bioprocess Engineering Vol.25 No.3

The effects of different oxygen uptake rates (OUR) on the physiological metabolism of Rhodobacter sphaeroides were investigated systematically in 50 L fermenters due to the significant influence on industrial coenzyme Q10 production under oxygen supply limitation. Meanwhile, the seriously decreased oxygen transfer rate caused by the increased broth viscosity was successfully prevented with OUR-directed continuous ammonium sulfate feeding in the late fermentation phase. The statistical analysis results showed that controlling OUR constantly at 45 ± 2.2 mmol/L/h by the oxygen supply level adjustment and the continuous ammonium sulfate feeding could greatly enhance Q10 production. This OUR-Stat controlling strategy successfully achieved the maximal coenzyme Q10 production (2584 ± 82 mg/L), which was 15.4% higher than that of the control. The highest specific CoQ10 content was 25.9 mg/(g DCW)), and the yield of CoQ10 to glucose consumption was up to 19.37 mg/g. These results demonstrated that the optimal OUR-Stat controlling strategy would be effective and economical for improving the industrial CoQ10 production.

Pavement Crack Detection by Ridge Detection on Fractional Calculus and Dual-thresholds

Song Hongxun,Wang Weixing,Wang Fengping,Wu Linchun,Wang Zhiwei 보안공학연구지원센터 2015 International Journal of Multimedia and Ubiquitous Vol.10 No.4

In this paper, a new road surface crack detection algorithm is proposed; it is based on the ridge edge detection on fractional calculus and the dual-thresholds on a binary image. First, the multi-scale reduction of image data is used to shrink an original image to eliminate noise, which can not only smooth an image but also enhance cracks. Then, the main cracks are extracted by using the ridge edge detection on fractional calculus in a grey scale image. Subsequently, the resulted binary image is further processed by applying both short and long line thresholds to eliminate short curves and noise for getting rough crack segments. Finally the gaps in cracks are connected with a curve connection function which is an artificial intelligence routine. The experiments show that the algorithm for pavement crack images has the good performance of noise immunity, accurate positioning, and high accuracy. It can accurately locate and detect small and thin cracks that are difficult to identify by other traditional algorithms.

Simulation and performance evaluation of the anoxic/anaerobic/aerobic process for biological nutrient removal

Zhen Zhou,Zhichao Wu,Zhiwei Wang,Shujuan Tang,Guowei Gu,Luochun Wang,Yingjun Wang,Zhiling Xin 한국화학공학회 2011 Korean Journal of Chemical Engineering Vol.28 No.5

As a modified configuration of the conventional anaerobic/anoxic/aerobic (AAO) process, a novel anoxic/anaerobic/aerobic (Reversed AAO, RAAO) process has been extensively applied in domestic wastewater treatment plants (WWTP). In this study, the Activated Sludge Model No. 2d (ASM2d) and a secondary clarifier model were calibrated and applied to simulate a pilot-scale RAAO test and evaluate the operational performance of the RAAO process. For calibration of the biological model ASM2d, only four kinetic parameters were adjusted to accurately simulate in-process variations of ammonium, nitrate and phosphate. Simulation results by the calibrated model demonstrated that phosphorus accumulating organisms (PAO) in the RAAO process (0.243 gP·(gCOD)^−1) contains less poly-phosphate than the AAO process (0.266 gP·(gCOD)^−1). With the increasing mixed liquor recirculation ratio in the RAAO process,the fraction of heterotrophic biomass and autotrophic biomass both increased, whereas the PAO decreased owing to adverse effects of electron acceptors on phosphorus release and poly-hydroxy-alkanoates synthesis.

Dual-anchor anti-corrosion coating of copper foil for high-speed interconnects

Huijuan Shi,Guoyun Zhou,Qin Zhang,Pengju Wang,Yan Hong,Wei He,Shouxu Wang,Chong Wang,Zhiwei Han 한국공업화학회 2023 Journal of Industrial and Engineering Chemistry Vol.126 No.-

In this experiment, two similar molecules with bifunctional groups have been characterized to prove theadvantages of dual-anchor molecular coating in the interfacial modification of the copper foil. The physicochemicalproperties of the modified copper foils have been studied. The obtained results indicate thatthe anti-corrosion performance and peeling strength were significantly improved for the copper foil treatedwith (2-(Methylthio)pyrimidin-4-yl)methanamine (MET), whose bonding information was analyzedvia the density functional theory calculation. It was found that the S-Cu and N-Cu bonds were bothformed on the Cu (1 1 1) surface for MET coating, and the adsorption of the double anchor pointsimproves the stability of the interface. The peeling test exhibits the function of MET coating as the adhesionpromotor between low-surface profile copper and resin for high-speed signal transmission.

Toothpaste microstructure and rheological behaviors including aging and partial rejuvenation

Zhiwei Liu,Lei Liu,Huan Zhou,Jiali Wang,Linhong Deng 한국유변학회 2015 Korea-Australia rheology journal Vol.27 No.3

Toothpastes are mainly composed of a dense suspension of abrasive substances, flavors, and therapeutic ingredients in a background liquid of humectants and water, and usually exhibit complex rheological behaviors. However, the relationship between the rheology and microstructure of toothpaste remains to be studied. In this paper, three commonly used toothpastes, namely Colgate, Darlie and Yunnan Baiyao (Ynby), were qualitatively and quantitatively studied as soft glassy materials. We found that although the three toothpastes generally behaved in similar fashion in terms of rheology, each particular one was distinct from others in terms of the quantitative magnitude of the rheologcial properties including thixotropy, creep and relaxation, yield stress, and power-law dependence of modulus on frequency. In addition, the history-dependent effects were interpreted in terms of aging and rejuvenation phenomena, analogous to those existing in glassy systems, and Ynby seemed to result in greater extent of aging and rejuvenation as compared to the other two. All these differences in toothpaste rheology may well be attributed to the different microscopic network microstructures as observed in this study. Therefore, this study provides first evidence of microstructurebased rheological behaviors of toothpaste, which may be useful for optimizing its composition, manufacturing processing as well as end-user applications

Smart Anti-jamming Mobile Communication for Cloud and Edge-Aided UAV Network

( Zhiwei Li ),( Yu Lu ),( Zengguang Wang ),( Wenxin Qiao ),( Donghao Zhao ) 한국인터넷정보학회 2020 KSII Transactions on Internet and Information Syst Vol.14 No.12

The Unmanned Aerial Vehicles (UAV) networks consisting of low-cost UAVs are very vulnerable to smart jammers that can choose their jamming policies based on the ongoing communication policies accordingly. In this article, we propose a novel cloud and edge-aided mobile communication scheme for low-cost UAV network against smart jamming. The challenge of this problem is to design a communication scheme that not only meets the requirements of defending against smart jamming attack, but also can be deployed on low-cost UAV platforms. In addition, related studies neglect the problem of decision-making algorithm failure caused by intermittent ground-to-air communication. In this scheme, we use the policy network deployed on the cloud and edge servers to generate an emergency policy tables, and regularly update the generated policy table to the UAVs to solve the decision-making problem when communications are interrupted. In the operation of this communication scheme, UAVs need to offload massive computing tasks to the cloud or the edge servers. In order to prevent these computing tasks from being offloaded to a single computing resource, we deployed a lightweight game algorithm to ensure that the three types of computing resources, namely local, edge and cloud, can maximize their effectiveness. The simulation results show that our communication scheme has only a small decrease in the SINR of UAVs network in the case of momentary communication interruption, and the SINR performance of our algorithm is higher than that of the original Q-learning algorithm.