Heteroatoms in situ-doped hierarchical porous hollow-activated carbons for high-performance supercapacitor

Yan Rui,Wang Kai,Tian Xiaodong,Li Xiao,Yang Tao,Xu Xiaotong,He Yiting,Lei Shiwen,Song Yan 한국탄소학회 2020 Carbon Letters Vol.30 No.3

Heteroatoms in situ-doped hierarchical porous hollow-activated carbons (HPHACs) have been prepared innovatively by pyrolyzation of setaria viridis combined with alkaline activation for the frst time. The micro-morphology, pore structure, chemical compositions, and electrochemical properties are researched in detail. The obtained HPHACs are served as outstand�ing electrode materials in electrochemical energy storage ascribe to the particular hierarchical porous and hollow structure, and the precursor setaria viridis is advantage of eco-friendly as well as cost-efective. Electrochemical measurement results of the HPHACs electrodes exhibit not only high specifc capacitance of 350 F g−1 at 0.2 A g−1, and impressive surface specifc capacitance (Cs) of 49.9 μF cm−2, but also substantial rate capability of 68% retention (238 F g−1 at 10 A g−1) and good cycle stability with 99% retention over 5000 cycles at 5 A g−1 in 6 M KOH. Besides, the symmetrical supercapacitor device based on the HPHACs electrodes exhibits excellent energy density of 49.5 Wh kg−1 at power density of 175 W kg−1 , but still maintains favorable energy density of 32.0 Wh kg−1 at current density of 1 A g−1 in 1-ethy-3-methylimidazolium tetrafuoroborate (EMIMBF4) ionic liquid electrolyte, and the excellent cycle stability behaviour shows the nearly 97% ratio capacitance retention of the initial capacitance after 10,000 cycles at current density of 2 A g−1. Overall, the results indicate that HPHACs derived from setaria viridis have appealing electrochemical performances thus are promising electrode materi�als for supercapacitor devices and large-scale applications.

Aerodynamic optimization of a high-expansion ratio organic radial-inflow turbine

Yan Li,Xue-song Li,Xiaodong Ren 대한기계학회 2016 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.30 No.12

Given that the radial-inflow turbine is a critical component of the Organic Rankine cycle system, its performance substantially influences system capacity. This paper established an optimization framework for the radial-inflow turbine is established with the combination of a computational fluid dynamics software, a non-uniform rational B-spline parameterization method, and an optimization strategy. The nozzle, meridional flow path, and blade profile of a 500 kW turbine were optimized. Results show that nozzle blade and impeller optimization leads to a 0.34 % and about 0.71 % increase in turbine efficiency, respectively. After optimization, the flow state in the turbine was good, and the flow separation almost disappeared.

Measurement of undesirable neutron spectrum in a 120 MeV linac

Yan Yihong,Tan Xinjian,Weng Xiufeng,Zhang Xiaodong,Zhang Zhikai,Sun Weiqiang,Hu Guang,Hu Huasi 한국원자력학회 2023 Nuclear Engineering and Technology Vol.55 No.10

Photoneutron background spectroscopy observations at linac are essential for directing accelerator shielding and subtracting background signals. Therefore, we constructed a Bonner Sphere Spectrometer (BSS) system based on an array of BF3 gas proportional counter tubes. Initially, the response of the BSS system was simulated using the MCNP5 code. Next, the response of the system was calibrated by using neutrons with energies of 2.86 MeV and 14.84 MeV. Then, the system was employed to measure the spectrum of the 241AmeBe neutron source, and the results were unfolded by using the Gravel and EM algorithms. Using the validated system, the undesirable neutron spectrum of the 120 MeV electron linac was finally measured and acquired. In addition, it is demonstrated that the equivalent undesirable neutron dose at a distance of 3.2 m from the linac is 19.7 mSv/h. The results measured by the above methods could provide guidance for linac-related research.

Morphology characterization of micro-gap oil film of tilting pad hydrostatic bearing under extreme working conditions

Xiaodong Yu,Yanan Feng,Yan Zhao,Dianbin Huang,Jianhua Jiao 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

Taking the hydrostatic support of the tiltable oil pad double rectangular cavity as the object, the fluid-thermal-solid coupling deformation analysis of the friction pair is carried out, and the three-dimensional morphology of the micro-gap oil film is obtained. An oil film thickness test device is built to verify the rationality of the numerical simulation method. It is found that the elastic deformations of rotational workbench and base under extreme loads are both concave deformations, the thermal deformations are both convex deformations, and the maximum thermal deformation is mainly concentrated on the outer oil sealing edge. The deformation of the downstream side oil sealing edge is higher than that of the reverse side oil sealing edge. The minimum oil film thickness is the minimum distance between the downstream side oil sealing edge and the lower surface of the hydrostatic guideway of the rotational workbench, where tribological failure is prone to occur.

Comparison of image masking methods for pump impeller blade region PIV experiments

Xiaodong Liu,Tingting Yan,Qiang Zhong,Zhuqing Liu,Fujun Wang,Yaojun Li,Wei Yang 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.6

Due to the blade reflection effect when applying the PIV technology to the internal flow field measurement of rotating machinery, the blade area requires special treatment. In this paper, zero-value, particle image, random number, and mean-value masking methods are compared and analyzed based on particle images from the PIV challenge and rotating impeller. The peak significance and coordinates deviations are used as the masking effect evaluation criteria. The results indicate that an increase in the interrogation window masking area proportion causes a weakening of the PIV calculation particle cluster displacement peak value. The peak position is shifted, which leads to the wrong velocity vector. The masking area proportion should not be higher than 0.7, 0.5, 0.19, and 0.22 for mean-value, random number, zero-value, and particle image masking methods, respectively. The results show that flow field calculation results near the blade boundary are more accurate for mean-value masking.

Performance evaluation of Collaborative Learning and E-commerce Security : Comprehensive Ability of China's PE Teachers to Use Computer

Zhang Yan,Wei Dongyi,Liu Yichong,Long Xiaodong,Tao Ganchen 보안공학연구지원센터 2016 International Journal of Security and Its Applicat Vol.10 No.1

In this paper, we discuss the current situation of the comprehensive computer ability of PE teachers in colleges, and find out deficiencies, then provide valuable theoretical basis for optimized development. A total of 122 PE teachers were selected as the research objects of the network questionnaire during July 2014 and December 2014, and we investigate related data of those teachers, by using reliability and validity test, we find out relationship between their ability to use computers and the basic information. The results shows that the P value of the comprehensive ability to use computers of PE teachers in colleges and universities is less than 0.01 by sex, region, age group, school age, title, educational background structure, highest level of papers published in the past 5 years and the highest level of completed topics within the past 5 year.

Phloretin targets SIRT1 to alleviate oxidative stress, apoptosis, and inflammation in deep venous thrombosis

Wang Xiaodong,Yan Jin,Ni Xiaolong,Hu Sipin,Zhang Mingwan,Ying Yin 한국독성학회 2024 Toxicological Research Vol.40 No.1

Deep vein thrombosis (DVT) is a type of venous thromboembolism posing a serious threat to health on a global scale. Phloretin is a potential natural product that has a variety of pharmacological activities. Besides, some Chinese medicines reported that deacetylase sirtuin (SIRT)1 treats DVT by anti-inflammatory and anti-platelet production. However, the specific binding targets and binding modes have not been elaborated. The present study was to investigate whether phloretin attenuates DVT in model rats and oxidized low‑density lipoprotein (ox‑LDL) induced human umbilical vein endothelial cells (HUVECs), and to explore its potential target. The results revealed that the treatment of phloretin, especially pretreatment of it elevated tissue plasminogen activator (t-PA), superoxide dismutase (SOD), prothrombin time (PT), thrombin time (TT), activated partial thromboplastin time (APTT), and cell apoptosis proteins whereas it suppressed plasminogen activator inhibitor (PAI), malondialdehyde (MDA), reactive oxygen species (ROS), fibrinogen (FIB) in DVT rats and cells. Concurrently, phloretin inhibited collagen type I alpha 1 (COL1A1), transforming growth factor-β1 (TGF-β1), and inflammatory factors while it enhanced nuclear factor erythroid 2-related factor 2 (Nrf-2), heme oxygenase 1 (HO-1). In addition, 20 μM phloretin exerted powerful effective protection in HUVECs with DVT model. Later, the surface plasmon resonance (SPR) confirmed that phloretin has a high affinity with SIRT1. Furthermore, siRNA-SIRT1 transfection abolished the protective effect of phloretin against ox‑LDL‑induced DVT in HUVECs, indicating that phloretin targets SIRT1 to alleviate oxidative stress, cell apoptosis, and inflammation in DVT rats and HUVECs.

Dark Septate Endophyte (DSE) Fungi Isolated from Metal Polluted Soils: Their Taxonomic Position, Tolerance, and Accumulation of Heavy Metals In Vitro

Yujie Zhang,Yan Zhang,Maojun Liu,Xiaodong Shi,Zhiwei Zhao 한국미생물학회 2008 The journal of microbiology Vol.46 No.6

To understand the possible role of the plant root associated fungi on metal tolerance, their role in the uptake of heavy metals and the potential transfer of these metal ions to the plant, three strains of dark septate endophytic (DSE) fungi were isolated from a waste smelter site in southwest China, and one strain was isolated from a non-contaminated site. According to molecular phylogenetic analysis of the ITS 1-5.8S rDNA-ITS 2 gene regions and morphological characteristics, one is identified as Exophiala pisciphila, and the other three are non-sporulating fungi under the experiment condition with the nearest phylogenetic affinities to the Thysanorea papuana strain EU041814. Tolerance and accumulation abilities of the three DSE strains for metals were investigated in liquid culture. Minimum inhibitory concentrations (MIC) of Pb, Zn, and Cd were determined. It was demonstrated that the tolerance of the DSE strains varied between metal species and strains. The E. pisciphila strain is able to accumulate lead and cadmium over 20% and 5% of dry weight of biomass, respectively. Partial of the sequestrated metals can be washed with CaCl2. Morphological and enzyme activity changes taking place in the presence of excessive Pb, Cd, and/or Zn also indicate that the mechanism of heavy metal tolerance and accumulation of the DSE strains would be a complex process. The findings indicated promising tolerance and accumulation of the DSE strains with potential values in metal cycling and restoration of soil and water system.

Camphor wood waste‑derived microporous carbons as high‑performance electrode materials for supercapacitors

Chenfeng Ding,Xiaodong Yan,Jin‑le Lan,Seungkon Ryu,Yunhua Yu,Xiaoping Yang 한국탄소학회 2019 Carbon Letters Vol.29 No.3

Sustainable biomass-derived porous carbons demonstrate excellent capacitive properties owing to their heteroatom-rich nature and distinct textural feature. Herein, a series of nitrogen-/phosphorus-/oxygen-containing microporous carbons (CWWN/ P/O-MPCs) have been successfully fabricated by etching in H2O2 solution, pre-treatment of camphor wood wastes with KOH solution and subsequent carbonization. As an electrode material for supercapacitors, the typical microporous carbon (CWW-N/P/O-MPCs-0.5) exhibits a remarkably high specific capacitance of 245 F g− 1 at 0.5 A g− 1, corresponding to an impressively large volumetric capacitance of 208 F m− 3, and excellent long-term stability over 10,000 cycles. The excellent electrochemical performance can be ascribed to the optimal combination of heteroatom groups and ultrafine micropores.

Camphor wood waste-derived microporous carbons as high-performance electrode materials for supercapacitors

Ding Chenfeng,Yan Xiaodong,Lan Jin-le,유승곤,Yu Yunhua,Yang Xiaoping 한국탄소학회 2019 Carbon Letters Vol.29 No.3

Sustainable biomass-derived porous carbons demonstrate excellent capacitive properties owing to their heteroatom-rich nature and distinct textural feature. Herein, a series of nitrogen-/phosphorus-/oxygen-containing microporous carbons (CWW-N/P/O-MPCs) have been successfully fabricated by etching in H2O2 solution, pre-treatment of camphor wood wastes with KOH solution and subsequent carbonization. As an electrode material for supercapacitors, the typical microporous carbon (CWW-N/P/O-MPCs-0.5) exhibits a remarkably high specific capacitance of 245 F g−1 at 0.5 A g−1, corresponding to an impressively large volumetric capacitance of 208 F m−3, and excellent long-term stability over 10,000 cycles. The excellent electrochemical performance can be ascribed to the optimal combination of heteroatom groups and ultrafine micropores.