Aprotic and Aqueous Li–O₂ Batteries

Lu, Jun,Li, Li,Park, Jin-Bum,Sun, Yang-Kook,Wu, Feng,Amine, Khalil American Chemical Society 2014 Chemical reviews Vol.114 No.11

<P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/chreay/2014/chreay.2014.114.issue-11/cr400573b/production/images/medium/cr-2013-00573b_0033.gif'></P>

Preparation of lithium-doped NaV6O15 thin film cathodes with high cycling performance in SIBs

Xu Hai-Yan,Ruan Jun Hai,Liu Fang Lin,Li Dong-Cai,Zhang Feng-Jun,Wang Ai-Guo,Sun Dao-Sheng,오원춘 한국세라믹학회 2022 한국세라믹학회지 Vol.59 No.3

Lithium ions-doped NaV6O15 thin films have been prepared using a simple low temperature liquid phase deposition method and subsequent annealing process. X-ray diffraction (XRD), Fourier transform infrared spectrometer (FTIR), scanning elec- tron microscopy (SEM), and photoelectron spectroscopy (XPS) have been used to study the structural and physicochemical characteristics of the NaV6O15 film. The films were grown on the FTO conductive glass and used directly as an electrode of sodium ion batteries. The prepared lithium ions-doped NaV6O15 thin film electrodes showed an excellent cycling stability and discharge capacity, which may be attributed to the stability of the Li+ embedded into the gap between the V–O layers to maintain the structure and its stable β-phase structure transformed after the first cycle. The cycling stability greatly improved with increasing annealing temperature, while the discharge capacity decreased. The capacities of the film electrodes annealed at 400 °C and 450 °C maintained above 97% after 100 cycles. The lithium-doped NaV6O15 underwent a phase transition dur- ing the first charge/discharge cycle. The new transformed phase has perfect crystal structure stability undergoing insertion and deinsertion of Na+. Therefore, the lithium-doped NaV6O15 thin film possesses good cycling stability and is expected to be a promising thin film cathode for sodium-ion batteries.

A large-area free-standing graphene oxide multilayer membrane with high stability for nanofiltration applications

Chen, Long,Li, Yanhui,Chen, Lina,Li, Na,Dong, Chenglong,Chen, Qiong,Liu, Beibei,Ai, Qing,Si, Pengchao,Feng, Jinkui,Zhang, Lin,Suhr, Jonghwan,Lou, Jun,Ci, Lijie Elsevier 2018 CHEMICAL ENGINEERING JOURNAL -LAUSANNE- Vol.345 No.-

<P><B>Abstract</B></P> <P>A flexible and free-standing graphene oxide and nylon 6 (GO@nylon 6) multilayer nanofiltration membrane was prepared by a layer-by-layer assembly process. The combination of electrospinning and electrospraying technique was employed, which can facilely prepare large-area membrane with size of 20 × 30 cm. The mechanical stability of multilayer membrane has enhanced significantly due to the tightly locked structure achieved by nylon 6 nanofibers network. The novel GO@nylon 6–13 multilayer nanofiltration membrane demonstrated a pure water flux up to 11.15 L m<SUP>−2</SUP> h<SUP>−1</SUP> bar<SUP>−1</SUP>, while keeping high organic dye rejection rate (>95% for methylene blue, and >99% for methyl orange). The rejections rate of the Na<SUB>2</SUB>SO<SUB>4</SUB>, NaCl, CuSO<SUB>4</SUB>, and Pb(NO<SUB>3</SUB>)<SUB>2</SUB> were 56.5%, 27.6%, 36.7%, and 18.9%, respectively. Furthermore, GO@nylon 6–13 multilayer nanofiltration membrane also demonstrated a high flux of some common organic solvents (8.4, 5.3, and 0.8 L m<SUP>−2</SUP> h<SUP>−1</SUP> bar<SUP>−1</SUP> for methanol, ethanol, and NMP, respectively), showing excellent chemical stability for separation process in those solvents.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Large-area GO@nylon 6 multilayer nanofiltration membrane was prepared. </LI> <LI> The multilayer structure enhances the mechanical stability. </LI> <LI> The multilayer membrane demonstrates a high water flux. </LI> <LI> The multilayer membrane shows high rejection rate for organic dyes. </LI> </UL> </P> <P><B>Graphical abstract</B></P> <P>Photograph and cross-section SEM image of GO@nylon 6 multilayer nanofiltration membrane, the inset shows the water contact angle.</P> <P>[DISPLAY OMISSION]</P>

Biochar-supported nZVI (nZVI/BC) for contaminant removal from soil and water: A critical review

Wang, Shengsen,Zhao, Mingyue,Zhou, Min,Li, Yuncong C.,Wang, Jun,Gao, Bin,Sato, Shinjiro,Feng, Ke,Yin, Weiqin,Igalavithana, Avanthi Deshani,Oleszczuk, Patryk,Wang, Xiaozhi,Ok, Yong Sik Elsevier 2019 Journal of hazardous materials Vol.373 No.-

<P><B>Abstract</B></P> <P>The promising characteristics of nanoscale zero-valent iron (nZVI) have not been fully exploited owing to intrinsic limitations. Carbon-enriched biochar (BC) has been widely used to overcome the limitations of nZVI and improve its reaction with environmental pollutants. This work reviews the preparation of nZVI/BC nanocomposites; the effects of BC as a supporting matrix on the nZVI crystallite size, dispersion, and oxidation and electron transfer capacity; and its interaction mechanisms with contaminants. The literature review suggests that the properties and preparation conditions of BC (e.g., pore structure, functional groups, feedstock composition, and pyrogenic temperature) play important roles in the manipulation of nZVI properties. This review discusses the interactions of nZVI/BC composites with heavy metals, nitrates, and organic compounds in soil and water. Overall, BC contributes to the removal of contaminants because it can attenuate contaminants on the surface of nZVI/BC; it also enhances electron transfer from nZVI to target contaminants owing to its good electrical conductivity and improves the crystallite size and dispersion of nZVI. This review is intended to provide insights into methods of optimizing nZVI/BC synthesis and maximizing the efficiency of nZVI in environmental cleanup.</P> <P><B>Highlights</B></P> <P> <UL> <LI> Aggregation and passivation of nZVI can be alleviated by surfactants and doping methods. </LI> <LI> BC hinders corrosion and improves the dispersion and electron transfer of nZVI. </LI> <LI> Properties of nZVI depend on those of the BC, feedstock and pyrogenic temperature. </LI> <LI> BC enhances electron transfer from nZVI to the contaminants due to the presence of quinone and graphene moieties. </LI> <LI> nZVI/BC shows strong ability to remove HMs, nitrates, and organic contaminants in soil and water. </LI> </UL> </P>

Research on the motion characteristics of a trans-media vehicle when entering water obliquely at low speed

Li, Yong-li,Feng, Jin-fu,Hu, Jun-hua,Yang, Jian The Society of Naval Architects of Korea 2018 International Journal of Naval Architecture and Oc Vol.10 No.2

This paper proposes a single control strategy to solve the problem of trans-media vehicle difficult control. The proposed control strategy is just to control the vehicle's air navigation, but not to control the underwater navigation. The hydrodynamic model of a vehicle when entering water obliquely at low speed has been founded to analyze the motion characteristics. Two methods have been used to simulate the vehicle entering water in the same condition: numerical simulation method and theoretical model solving method. And the results of the two methods can validate the hydrodynamic model founded in this paper. The entering water motion in the conditions of different velocity, different angle, and different attack angle has been simulated by this hydrodynamic model and the simulation has been analyzed. And the change rule of the vehicle's gestures and position when entering water has been obtained by analysis. This entering water rule will guide the follow-up of a series of research, such as the underwater navigation, the exiting water process and so on.

Experimental and Numerical Research on Process Formability in Magnetic Pulse Forming of AZ31 Magnesium Alloy Sheets

Jun-Rui Xu,Jun-Jia Cui,Guangyong Sun,Yan-Rong Li,Chun-Feng Li 한국정밀공학회 2015 International Journal of Precision Engineering and Vol. No.

The plain strain of AZ31 magnesium alloy sheet in magnetic pulse forming was investigated by numerical simulation and experimental method. Combination of uniform pressure coil and Holmberg's specimen was employed to evaluate the plain strain of AZ31 sheet. The numerical simulation for magnetic pulse plain strain of AZ31 sheet is performed by means of ANSYS FEA software. The magnetic flux density of uniform pressure coil was distributed uniformly, especially at the center of gauged area of AZ31 sheet directly in relation to the deformation behavior of AZ31 sheet. The velocity of typical point increases as increasing energy, and the more position closes to the center of sheet the higher velocity achieves. The forming height is increased with increasing discharge voltage. Compared with C=768 μF and C=1536 μF, the capacitance of 1152 μF is more effective for forming, which is confirmed by experiments. The peak velocity at the center of sheet is about 105 m/s. The major strains of magnetic pulse plane strain lie approximately in the strain ranges of 5.83-6.45%. However, the 3.22-3.82% (major strain) are the limit strains in quasi-static condition. The experimental results indicate that the major strain of AZ31 sheet improves about 75% compared with the quasi-static case.

Differences in the mandibular premolar positions in Angle Class I subjects with different vertical facial types

Jun Duan,Feng Deng,Wan-Shan Li,Xue-Lei Li,Lei-Lei Zheng,Gui-Yuan Li,Yan-Jie Bai 대한치과교정학회 2015 대한치과교정학회지 Vol.45 No.4

Objective: To compare the positions of the mandibular premolars in Angle Class I subjects according to vertical facial type. The results will provide a theoretical basis for predicting effective tooth movement in orthodontic treatment. Methods: Cephalometric parameters were determined using cone-beam computed tomography in 120 Angle Class I subjects. Subjects were categorized as short, normal, and long face types according to the Frankfort mandibular angle. Parameters indicating the position of the mandibular right premolars and the mandible were also measured. Results: The angle between the mandibular first premolar axis and buccal cortex, the distance between the root apex and buccal cortex, angle of vestibularization, arc of vestibularization, and root apex maximum movable distance were significantly greater in the short face type than in the long and norm face types. The angle between the mandibular second premolar axis and buccal cortex, the distance from root apex to buccal cortex, and the arc of vestibularization were significantly greater in the short face type than in the normal face type. Conclusions: There are significant differences in the mandibular premolar positions in Class I subjects according to vertical facial type.

Boosting oxygen reduction catalysis with abundant copper single atom active sites

Li, Feng,Han, Gao-Feng,Noh, Hyuk-Jun,Kim, Seok-Jin,Lu, Yalin,Jeong, Hu Young,Fu, Zhengping,Baek, Jong-Beom The Royal Society of Chemistry 2018 Energy & environmental science Vol.11 No.8

<P>With their high catalytic activity, stability, selectivity, and 100% atom utilization, single atomic non-noble metal based materials are valuable alternatives to efficient but expensive Pt based catalysts. For efficient catalysis, single-atom catalysts must expose abundant single atomic metal active centers. Here, we report the rational design and synthesis of a Cu single-atom catalyst with high Cu content of over 20.9 wt%, made of single atomic Cu anchored into an ultrathin nitrogenated two-dimensional carbon matrix (Cu-N-C). The high Cu content was achieved by the introduction of additional N species, which can securely trap and protect the Cu atoms. During oxygen reduction, the single atomic Cu exhibited over 54 times higher mass activity than metallic Cu nanoparticles at a potential of 0.85 V <I>versus</I> a reversible hydrogen electrode (RHE). Furthermore, the Cu-N-C exhibited 3.2 times higher kinetic current at 0.85 V (<I>vs.</I> RHE), and a much lower Tafel slope (37 mV dec<SUP>−1</SUP>), as well as better methanol/carbon monoxide tolerance and long-term stability than commercial Pt/C. Density functional theory (DFT) calculations reveal that the Cu active sites exhibit improved O-O bond stretching and favorable adsorption energies of O2 and OOH for four-electron oxygen reduction.</P>

Research on the Oxidation-Protective Coatings for Carbon/Carbon Composites

Li, He-Jun,Fu, Qian-Gang,Huang, Jian-Feng,Zeng, Xie-Rong,Li, Ke-Zhi Korean Carbon Society 2005 Carbon Letters Vol.6 No.2

Anti-oxidation coatings are the key technique for carbon/carbon (C/C) composites used as the thermal structural materials. The microstructure and oxidation behavior of several kinds of high-performance ceramic coatings for C/C composites prepared in Northwestern Polytechnical University were introduced in this paper. It showed that the ceramic coatings such as SiC, Si-$MoSi_2$, SiC-$MoSi_2$, $Al_2O_3$-mullite-SiC and SiC/yttrium silicate/glass coatings possessed excellent oxidation resistance at high temperatures, and some of these coatings were characterized with excellent thermal shock resistance. The SiC-$MoSi_2$ coating system has the best oxidation protective property, which can effectively protect C/C composites from oxidation up to 1973 K. In addition, the protection and failure reasons of some coatings at high temperature were also provided.

Prevalence of Spina Bifida Occulta and Its Relationship With Overactive Bladder in Middle-Aged and Elderly Chinese People

Jun Wei Wu,Yu Rong Xing,Yi Bo Wen,Tian Fang Li,Quan De Feng,Xiao Ping Shang,Yun Long Li,Jin Jin Feng,Xin Xin Wang,Rong Qun Zhai,Xiang Fei He,Tao Chen,Xin Jian Liu,Jian Guo Wen 대한배뇨장애요실금학회 2016 International Neurourology Journal Vol.20 No.2

Purpose: To investigate the prevalence of spina bifida occulta (SBO) and its relationship with the presence of overactive bladder (OAB) in middle-aged and elderly people in China. Methods: A cross-sectional community-based survey was carried out at 7 communities in Zhengzhou City, China from December 15, 2013 to June 10, 2014, where residents aged over 40 years were randomly selected to participate. All of the participants underwent lumbosacral radiographic analysis and relevant laboratory tests. A questionnaire including basic information, past medical history and present illness, and the OAB symptom score was filled out by all participants. Chi-square tests and logistic regression were used for data analysis with a P-value of <0.05 denoting statistical significance. Results: A total of 1,061 subjects were qualified for the final statistical analysis (58.8±11.7 years; male, 471 [44.4%]; female, 590 [55.6%]). The overall prevalence of SBO was 15.1% (160 of 1,061): 18.3% (86 of 471) in men and 12.5% (74 of 590) in women. Among these subjects, 13.7% (145 of 1,061) had OAB: 13.2% (62 of 471) in men and 14.1% (83 of 590) in women. The results of logistic regression showed that age, SBO, history of cerebral infarction (HCI), and constipation were risk factors for OAB (P<0.05), while sex, history of childhood enuresis (HCE), body mass index (BMI), and diabetes mellitus (DM) were not (P>0.05). In men, age, SBO, and constipation were risk factors for OAB (P<0.05), while HCE, BMI, DM, HCI, and benign prostate hyperplasia were not (P>0.05). In women, age, SBO, and HCI were risk factors for OAB (P<0.05), while HCE, BMI, DM, vaginal delivery, and constipation were not (P>0.05). Conclusions: The prevalence of SBO is high and it is related to OAB in middle-aged and elderly people in China.