Selective oxidation of 5-formyloxymethylfurfural to 2, 5-furandicarboxylic acid with Ru/C in water solution

Zhihao Si,Xin Zhang,Miao Zuo,Tao Wang,Yong Sun,Xing Tang,Xianhai Zeng,Lu Lin 한국화학공학회 2020 Korean Journal of Chemical Engineering Vol.37 No.2

2, 5-furandicarboxylic acid (FDCA) is a one of the most promising biomass-derived chemicals to substitute the non-renewable terephthalic acid as the monomer for producing polyethyleneterephthalate. At present, the oxidation of HMF is regarded as a prevalent way to prepare FDCA. Nevertheless, the isolation and storage of HMF is still a challenge. Herein, based on the higher stability of 5-formyloxymethylfurfural (FMF) than 5-hydroxymethylfurfural (HMF), we present an effective preparation route to prepare FDCA by substituting HMF with FMF as feedstock. A complete conversion of FMF and a 93.55% selectivity of FDCA were obtained in the mixed solvent of water and 1, 2- dioxane using Ru/C as catalyst and O2 as oxidant. An improved process was developed for preparing FDCA using FMF as feedstock. The investigation of conversion pathway showed that FMF and HMF were simultaneously oxidized to 2, 5-diformylfuran (DFF) in a case of the existence of the reversible equilibrium between FMF and HMF. Then DFF was oxidized to 5-formyl-2-furancarboxylic acid (FFCA). Subsequently, FFCA was oxidized to FDCA. In this process, the oxidation of FFCA to FDCA was determined as the rate-determining step. Furthermore, appropriate alkalinity favored the selectivity of FDCA and the conversion of FMF.

Performance of Contra-Rotating Propellers for Stratospheric Airships

Zhihao Tang,Peiqing Liu,Jingwei Sun,Yaxi Chen,Hao Guo,Guangchao Li 한국항공우주학회 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4

Small advance ratio and low Reynolds number of stratospheric propulsion system bring lots of challenges to the design of propellers. Contra-rotating propeller configuration is proposed to improve the propulsion efficiency. In this paper, the feasibility of contra-rotating propeller for stratospheric airship has been assessed and its performance has been investigated by wind tunnel tests. The experimental results indicate, at relatively low Reynolds number, although the advance ratio is fixed, the performance of propellers is different with variation of Reynolds number. Moreover, at the same Reynolds number, the efficiency of contra-rotating propeller achieved appears to be a few percent greater than that for a standard conventional propulsion system. It can be concluded that contra-rotating propellers would be an efficient means to improve the performance of stratospheric airship propulsion system.

Investigation into the Prestress Loss and Thermal Expansion Performance of Steel Cables at High Temperature

Guojun Sun,Zhihao Li,Jinzhi Wu,Xiushu Qu,Jingying Ren 한국강구조학회 2022 International Journal of Steel Structures Vol.22 No.3

This study investigates the prestress loss and thermal expansion performance of steel cables under high temperatures. The calculation formula of cable prestress loss is fi rst deduced theoretically. The prestress loss value of cable under force-thermal coupling is then obtained through numerical simulation and is compared with the calculation results of the theoretical formula. Theoretical deduction is then employed to determine the relationship between the thermal expansion coeffi cient of the cable and wire in the unstressed state. A numerical analysis model is established to simulate the mechanical properties of the cable in an unstressed state. The results show that the thermal expansion coeffi cient of the cable in an unstressed state is the same as that of steel wire. Finally, considering that the cable is in the stress state in an actual structure, the high-temperature prestress loss of steel cables under force-thermal coupling is obtained through simulation analysis. The equivalent thermal expansion coeffi cient is then calculated, and the infl uence of diff erent twist angles, steel wire layers, initial prestress, section type, and cable length on the equivalent thermal expansion coeffi cient of steel cables is determined.

Experimental Analysis and Evaluation of the Compressive Strength of Rubberized Concrete During Freeze–Thaw Cycles

Sheng Sun,Xiaoyan Han,Aijiu Chen,Qing Zhang,Zhihao Wang,Keliang Li 한국콘크리트학회 2023 International Journal of Concrete Structures and M Vol.17 No.4

Recycling scrap tires provides an alternative source of fine aggregates for the production of rubberized concrete and this will lead to significant increase in concrete frost resistance, environmental protection, and conservation of natural sand and gravel resources. In this paper, a total of 25 groups of rubberized concrete were produced by adding scrap tire rubber particles of different sizes, contents, and pretreatment methods to replace the fine aggregate, and their compressive strength during freeze–thaw cycles was studied from both the macro- and meso-perspectives. The results indicated that the decrease in concrete strength and weight was notably restricted by the presence of rubber particles during freeze–thaw cycles. The rubber fine aggregate with smaller particle sizes enhanced the concrete frost resistance more significantly, and the F100 of concrete with rubber particles of 1.0–2.0 mm increased from 76.6 to 86.5% by increasing the rubber content from 0.0 to 5.6%. The effects of rubber fine aggregate on concrete compressive strength during freeze–thaw cycles were quantified. On this basis, a forecast model for rubberized concrete compressive strength in freeze–thaw cycles was proposed, and the effects of the particle size, content, and pretreatment of the rubber particles were considered. The calculated results agreed well with the test results both in this study and the relevant peer studies, indicating that the model can provide a good reference for the design and engineering application of rubberized concrete in frigid environments.

Performance of Contra-Rotating Propellers for Stratospheric Airships

Tang, Zhihao,Liu, Peiqing,Sun, Jingwei,Chen, Yaxi,Guo, Hao,Li, Guangchao The Korean Society for Aeronautical and Space Scie 2015 International Journal of Aeronautical and Space Sc Vol.16 No.4

Small advance ratio and low Reynolds number of stratospheric propulsion system bring lots of challenges to the design of propellers. Contra-rotating propeller configuration is proposed to improve the propulsion efficiency. In this paper, the feasibility of contra-rotating propeller for stratospheric airship has been assessed and its performance has been investigated by wind tunnel tests. The experimental results indicate, at relatively low Reynolds number, although the advance ratio is fixed, the performance of propellers is different with variation of Reynolds number. Moreover, at the same Reynolds number, the efficiency of contra-rotating propeller achieved appears to be a few percent greater than that for a standard conventional propulsion system. It can be concluded that contra-rotating propellers would be an efficient means to improve the performance of stratospheric airship propulsion system.

Scale inhibition performance of calcium sulfate by 1,6-diaminohexanecontained polyaminoamide dendrimers: Static experiment and MD simulation

Yue Sun,Li Li,Zhihao Chen,Xiaoshuang Yin,Wenzhong Yang,Yun Chen,Ying Liu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.115 No.-

The calcium sulfate scale is a common scale in the industrial water system, which is difficult to beremoved by common chemical cleaning methods. In this paper, a new phosphorous free of 1,6-Diaminohexane-contained polyaminoamide dendrimers (PAMAM) scale inhibitor with a threedimensional(3D) branched structure has been developed. The scale inhibition performances of differentgenerations of PAMAM dendrimers (PAMAM-mid, PAMAM-0G, PAMAM-0.5G and PAMAM-1G) are estimatedby the static scale inhibition method. Moreover, the effects of the scale inhibitor concentrationsand solution temperatures on the CaSO4 scale inhibition efficiency are thoroughly discussed. Results indicatethat the PAMAM-mid and PAMAM-0.5G) exhibit excellent inhibition performance on CaSO4 precipitation. Especially, the CaSO4 scale inhibition efficiency of PAMAM-0.5G is above 95% when the dose is10 mg/L, and the corresponding value is almost 100% when the inhibitor dose is 20 mg/L. In addition,the influence of descaling agents on the crystal and morphology of CaSO4 scales are studied by XRDand SEM tests. The results show that the scale inhibition ability of the PAMAM molecules mainly inhibitsthe growth of these crystal planes by adsorption on the surface of the growing crystal. Molecular dynamicssimulation results find that the PAMAM-0.5G dendrimer molecule can energetically interact well withthree crystal planes of calcium sulfate dihydrate. Finally, the simulation results provide a theoreticalguidance to judge the performance of scale inhibitors and synthesize new high-efficiency scale inhibitor.

Simulation and Optimization of Crash Performance of Movable Barrier at Median Strip

Xianglong Sun,Zhihao Wang 대한토목학회 2022 KSCE JOURNAL OF CIVIL ENGINEERING Vol.26 No.2

To better evaluate the crash performance of the guardrail and reduce the number of actual vehicle crash tests, this paper uses mechanical analysis and finite element simulation technology to evaluate the typical movable guardrail and optimize the structure. It’s of great significance for improving the crashworthiness of this type of guardrail and enhancing its safety performance. Firstly, the vehicle-barrier mechanical model was established to calculate the vehicle collision force on the barrier. Secondly, the collision force model was used to calculate the collision of a 10-ton truck, and a finite element model of a typical movable barrier was established for a collision simulation. Finally, the wall thickness and column spacing were optimized according to the results. The simulation results show that the maximum lateral dynamic deformation of the barrier was 1,818 mm, which agrees with the actual vehicle test results (1,600 mm). When the wall thickness of the barrier increases by 2 mm, the maximum lateral dynamic deformation was 1,419 mm; When the spacing of strengthened columns was reduced to 15 m, the deformation was 1,364 mm; After optimization, the deformation was reduced by more than 20%, and the crashworthiness of barrier was improved obviously.

Enhanced adsorption capacity of dyes by surfactant-modified layered double hydroxides from aqueous solution

Bei Zhang,Zhihao Dong,Dejun Sun,Tao Wu,Yujiang Li 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.49 No.-

The utilization of organo-modified layered double hydroxides with anionic surfactants (organo-LDHs) asadsorbents were successfully carried out to remove various synthetic dyes from aqueous solution. Intercalation of anionic surfactants changed the surface properties of MgAl-LDH from hydrophilic tohydrophobic, and a charge inversion occurred with increasing the length of surfactant chains. Suchchanges in the surface properties of the organo-LDHs were important. Experimental data shown that theSNS-modified MgAl-LDH could be used as a broad-spectrum adsorbent to effectively remove anionic,non-ionic, and cationic dyes from aqueous solution.

Altered ER–mitochondria contact impacts mitochondria calcium homeostasis and contributes to neurodegeneration in vivo in disease models

Lee, Kyu-Sun,Huh, Sungun,Lee, Seongsoo,Wu, Zhihao,Kim, Ae-Kyeong,Kang, Ha-Young,Lu, Bingwei National Academy of Sciences 2018 PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF Vol.115 No.38

<P><B>Significance</B></P><P>Ca<SUP>2</SUP><SUP>+</SUP> regulates cellular metabolism, proliferation, and differentiation. Ca<SUP>2+</SUP> homeostasis is critical for cellular function and health. Mitochondria help buffer transient Ca<SUP>2+</SUP> elevations and prevent cell death induced by Ca<SUP>2+</SUP> overload. Mito-Ca<SUP>2+</SUP> is also required for optimal activity of certain key mitochondrial functions, such as oxidative phosphorylation and metabolism. Thus, mito-Ca<SUP>2+</SUP> homeostasis assumes central roles in cellular health. Endoplasmic reticulum (ER) and mitochondria make intimate contacts and exchange molecules such as Ca<SUP>2+</SUP> and lipids. We find that ER-to-mitochondria Ca<SUP>2+</SUP> transfer is important for mito-Ca<SUP>2+</SUP> homeostasis and that the conserved Miro protein is critically involved. We show that mito-Ca<SUP>2+</SUP> homeostasis is disrupted in neurodegenerative disease models and its restoration is beneficial. Our findings have important implications for therapeutic intervention of neurodegenerative diseases.</P><P>Calcium (Ca<SUP>2+</SUP>) homeostasis is essential for neuronal function and survival. Altered Ca<SUP>2+</SUP> homeostasis has been consistently observed in neurological diseases. How Ca<SUP>2+</SUP> homeostasis is achieved in various cellular compartments of disease-relevant cell types is not well understood. Here we show in <I>Drosophila</I> Parkinson’s disease (PD) models that Ca<SUP>2+</SUP> transport from the endoplasmic reticulum (ER) to mitochondria through the ER–mitochondria contact site (ERMCS) critically regulates mitochondrial Ca<SUP>2+</SUP> (mito-Ca<SUP>2+</SUP>) homeostasis in dopaminergic (DA) neurons, and that the PD-associated PINK1 protein modulates this process. In <I>PINK1</I> mutant DA neurons, the ERMCS is strengthened and mito-Ca<SUP>2+</SUP> level is elevated, resulting in mitochondrial enlargement and neuronal death. Miro, a well-characterized component of the mitochondrial trafficking machinery, mediates the effects of PINK1 on mito-Ca<SUP>2+</SUP> and mitochondrial morphology, apparently in a transport-independent manner. Miro overexpression mimics <I>PINK1</I> loss-of-function effect, whereas inhibition of Miro or components of the ERMCS, or pharmacological modulation of ERMCS function, rescued <I>PINK1</I> mutant phenotypes. Mito-Ca<SUP>2+</SUP> homeostasis is also altered in the LRRK2-G2019S model of PD and the PAR-1/MARK model of neurodegeneration, and genetic or pharmacological restoration of mito-Ca<SUP>2+</SUP> level is beneficial in these models. Our results highlight the importance of mito-Ca<SUP>2+</SUP> homeostasis maintained by Miro and the ERMCS to mitochondrial physiology and neuronal integrity. Targeting this mito-Ca<SUP>2+</SUP> homeostasis pathway holds promise for a therapeutic strategy for neurodegenerative diseases.</P>

Remaining useful life prediction of circuit breaker operating mechanisms based on wavelet‑enhanced dual‑tree residual networks

Tailong Wu,Yuan Yao,Zhihao Li,Binqiang Chen,Yue Wu,Weifang Sun 전력전자학회 2024 JOURNAL OF POWER ELECTRONICS Vol.24 No.1

The remaining useful life prediction of circuit breaker operating mechanisms is crucial for the condition-based maintenance of national power grids. To realize accurate remaining useful life prediction, a novel wavelet-enhanced dual-tree residual network is proposed in this paper. Through this wavelet transform, the time series is decomposed into two components (high frequency and low frequency). Then the two decomposed components are fed into two lightweight residual neural network structures. By concatenating the dual-tree features, the remaining useful life of a circuit breaker operating mechanism can be predicted. The proposed network is validated using a full-life cycle experiment of the circuit breaker operating mechanism. Results show that the proposed method has good capability when it comes to predicting the remaining useful life of the circuit breaker operating mechanism. Along with application in the construction of smart grids and green energy, it is expected that the proposed method has potential in running state prognostics of circuit breakers.