Fe3O4nanoparticles anchored on carbon nanotubes as high-performance anodes for asymmetric supercapacitors.

Fe3O4/CNT composites are synthesized with ethylene glycol as solvent by a one-step solvothermal method and used as anode materials for asymmetric supercapacitors (ASC). An appropriate amount of water in ethylene glycol can accelerate the formation of Fe3O4and reduce the average size of Fe3O4to around 20 nm. However, spherical Fe3O4particles larger than 100 nm will form in pure ethylene glycol for long reaction time. The Fe3O4/CNT composite with small Fe3O4nanoparticles exhibits a high specific surface area, promoted electron transfer ability, as well as a high utilization rate of active materials. The optimized electrode shows a high specific capacity of 689 C g-1at 1 A g-1, and remains 443 C g-1at 10 A g-1. The inferior long-term cycling stability is due to the phase transition of Fe3O4and a reductive effect to form metallic Fe. An ASC using Fe3O4/CNT and NiCoO2/C composites as anode and cathode, respectively, delivers a high energy density of 58.1 Wh kg-1at a power density of 1007 W kg-1in a voltage window of 1.67 V and has a capacity retention of 63% after 5000 cycles. The self-discharge behavior of the ASC is also investigated.

Controllable reduction of NiCoO2@NiCo core-shell nanospheres on CNTs for high-performance electrochemical energy storage.

The performances of energy storage devices are strongly dependent on the electrode materials. Owing to the high theoretical capacity, NiCoO2 is a promising transition metal oxide for supercapacitors. Despite many efforts have been devoted, it still lacks of effective methods to overcome its shortcomings such as low conductivity and poor stability, in order to achieve its theoretical capacity. Herein, utilizing the thermal reducibility of trisodium citrate and its hydrolyzate, a series of NiCoO2@NiCo/CNT ternary composites in which NiCoO2@NiCo core-shell nanospheres deposited on CNT surface with adjustable metal contents are synthesized. Benefiting from the enhanced synergistic effect of both metallic core and CNTs, the optimized composite exhibits an extremely high specific capacitance (2660 F g-1 at 1 A g-1, the effective specific capacitance of the loaded metal oxide is 4199 F g-1, close to the theoretical value), an excellent rate performance and stability, when the metal content is about 37%. After depolarized calculation, the energy storage mechanism of the composite is reasonably analyzed. By controlling the contents of hexamethylenetetramine, trisodium citrate and CNTs in the reactant, the roles of them are distinguished. This study reveals an efficient novel strategy for transition metal oxides to maximize the electrochemical performances.

NiCoO2 and polypyrrole decorated three-dimensional carbon nanofiber network with coaxial cable-like structure for high-performance supercapacitors.

Designing optimized nano-sized architecture is a promising approach to prepare high-performance electrode materials for supercapacitors. In this work, a hierarchical multi-shelled structure has been successfully synthesized, which consists of a 3D carbon nanofiber network as a supporting scaffold prepared by carbonization of aramid nanofiber aerogel, an intermediate polypyrrole (PPy) bonding layer and a NiCoO2 outer shell, just like a coaxial cable in the structure. The intermediate PPy layer facilitates the uniform deposition of NiCoO2 by providing more anchor sites, and enhances the electrical contact between carbon nanofiber network and NiCoO2 shell due to its high conductivity and good compatibility with two different substances. The synergistic effect of the hierarchical configuration endows the electrode material with a high specific capacitance of 1037 F g-1at 1 A g-1and excellent cycling stability (∼89% of initial capacitance after 7000 cycles). Moreover, an asymmetric supercapacitor based on the composite and activated carbon achieves a high energy density of 37.7 Wh kg-1 at a power density of 465 W kg-1 in 1.65 V. This work may provide a feasible strategy to design high-performance hybrid electrodes for energy storage devices.

[Application of a new type of angle-adjustable osteotomy guide in closing wedge distal femoral osteotomy].

Objective: To explore the feasibility of fast and accurate osteotomy using a new angle adjustable osteotomy guide (AAOG) in closing wedge distal femoral osteotomy(CWDFO). Methods: The clinical data of 14 patients (17 knees) with valgus knee treated with CWDFO at Department of Integrated Chinese and Western Medicine Orthopedics, Honghui Hospital, Xi'an Jiaotong University from January 2018 to July 2019 were analyzed retrospectively. There were 3 males and 11 females, aging (41.4±16.4) years (range: 18 to 56 years). The body mass index was (23.5±3.5) kg/m(2) (range: 18.1 to 28.9 kg/m(2)). The guide pins were placed with the assistance of the self-designed AAOG. Before the surgery, Solidworks software was used to calculate the correction angle and the osteotomy radius accurately. The osteotomy guide was adjusted according to these two parameters. During the surgery, the adjusted osteotomy guide was placed to the surface of bone closely and the guide pins were drilled into the bone through the guide holes. The position of the guide pins was confirmed under fluoroscopy. The osteotomy was finished under guide of pins and fixed with Tomofix plate (Synthes). The times and duration of placement of the guide pins, the times of X-ray examination, the planned and actual thickness of the osteotomy wedge, the top and bottom area of the osteotomy wedge, the posterior distal femoral angle(PDFA), the correction of the weight line, and the American Knee Society Score(AKSS) and Tegner scores were collected and compared by paired t test or Kruskal-Wallis non-parametric test. Healing time after osteotomy and complications were recorded. Results: The guide pins were successfully placed once in 10 knees, adjusted once in 5 knees and twice in 2 knees. The time spent in placing all the 6 pins was 82.4 seconds (range: 51 to 125 seconds), and the times of X-ray examination was 1.5 times (range: 1 to 5 times). The top and bottom areas of the osteotomy wedge were (5.52±0.52)cm(2) and (5.36±0.49)cm(2). PDFA was (85.2±2.6)° preoperatively and (85.5±1.4)° postoperatively (t=-0.401, P>0.05). The thickness of the osteotomy was (11.3±1.9)mm according to the preoperative plan, and the actual thickness was (8.1±1.7)mm. All the patients were followed up for 6 months after surgery and AKSS and Tegner scores improved significantly (all P<0.05). The correction of the weight lines was within the ideal range. Fractures of the hinge point occurred in 3 knees. All of the osseous healing without complications. Conclusion: The new osteotomy guide helps to place the guide pins rapidly and precisely according to the preoperative planning, which should be widely used in clinical applications with promising outcomes.

Phase synchronization in coupled Nd:YAG lasers.

We investigate experimentally the transition to phase synchronization in coupled Nd:YAG lasers. As the coupling strength increases, the phase difference of two chaotic laser outputs develops from nonsynchronous to a phase-synchronous state via +/-2pi phase jumps. We analyze this transition.

IgG and IgA antibodies to Epstein-Barr virus in nasopharyngeal carcinoma patients.

Immunoglobulin levels and IgG and IgA antibodies to Epstein-Barr virus (EBV), viral capsid antigens (VCA) and early antigens (EA) were tested in 67 untreated (5 stage I, 32 stage II, 16 stage III and 14 stage IV), 21 treated and 7 recurrent nasopharyngeal carcinoma (NPC) patients and 54 normal subjects. The mean serum concentrations of IgG, IgA and IgM in NPC patients were higher than those of the normal control. 41.1, 86.3, 94.7 and 95.8% of NPC patients had anti-VCA titers of greater than or equal to 1:640 and greater than or equal to 1:40 in IgG and IgA, and anti-EA titers of greater than or equal to 1:40 and greater than or equal to 1:10 in IgG and IgA, respectively. But none of the control had such titers. IgG and IgA levels, anti-VCA titers in IgG and IgA, and anti-EA titers in IgG increased with advances of the disease in untreated NPC patients. Untreated patients had higher anti-VCA titers in IgG, and anti-EA titers in IgG and IgA than 60Co-treated cases, but lower than recurrent patients. Anti-VCA in IgA and IgG was more closely correlated than anti-EA in IgA and IgG. Anti-VCA and anti-EA antibodies in IgA were detected from the throat washing of a NPC patient at clinical stage III.