Search

The development of hybrid supercapacitors is limited due to the low specific capacity of traditional carbon-negative materials. Herein, we synthesized two different Fe-based negative electrodes (FeOOH and Fe2O3), and the relationships between structures and capacitive properties of electrodes are systematically studied. Results demonstrate that the Fe2O3 material exhibits higher electrochemical activity than their FeOOH counterparts obtained under the same conditions. Then, a high energy density asymmetric supercapacitor is fabricated by using nanostructured NiCo2S4 and Fe2O3–RGO composite as the positive and negative electrodes, respectively. The assembled device with an extended operation voltage of 1.6 V achieves a maximum energy density of 53.0 Wh kg−1 at a power density of 716 W kg−1 and can still operate at a high power density of 11.5 KW kg−1 with an energy density of 14.2 Wh kg−1, thus holding great potentials for future energy storage devices.

Zhaoxia Zhang,* Dong Zhao,* Mei Lin, Dongxue Zhang, Ruijuan Bai, Jing Fan, Zuomin Wang Department of Stomatology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, People’s Republic of China *These authors contributed equally to this work Objectives: Based on the concept of health quotient (HQ), we designed and facilitated personalized plans to improve patients’ compliance and oral health. The study aims to increase HQ level of patients with chronic periodontitis from four aspects, namely self-care, health knowledge, lifestyle, and mental health, and evaluate the effects of HQ training in maintaining oral health.Method: In total, 105 patients with chronic periodontitis were recruited from Capital Medical University-Affiliated Beijing Chaoyang Hospital from January 2015 to January 2017. The patients were randomly split into two groups (control versus test). All the patients received standard periodontal treatments. In addition, patients in the control group received conventional oral health instructions, and patients in the test group received the HQ training. At the end of the training, oral health status of both groups was evaluated and recorded.Results: The oral health status and the HQ scores were significantly better in the test group than the control group (P

Plant trials of Al killed 60Si2MnA spring steel were performed under two different processes (LF + calcium treatment, LF + RH + calcium treatment). The T.[O] (total oxygen) contents, inclusions during the two processes and the fatigue lifes of finished steels were compared. Results showed the non-liquid and liquid Al2 O3 -SiO2 -CaO-MgO inclusions in steel both decreased with the RH time, the removal ratio of inclusions reached 46% after 20 min treatment. The liquid inclusions decreased steadily throughout all the RH time, but the non-liquid inclusions quickly decreased at 10 min, then showed down due to the possibly bad interfacial parameters. The average size of inclusions increased firstly and then decreased due to the collision and coagulation of the abundant inclusions (1–5μ m) in the first 10 min. As a result, RH degassing decreased the T.[O] content, as well as the number and size of inclusions in finished steel from 13 ppm, 5.2 per mm2 and 3.5 μ m to 6 ppm, 4.6 per mm2 and 2.4 μ m and encouraged the inclusions to transform from Al2 O3 -SiO2 -CaO-MgO to Al2 O3 -SiO2 -CaO-MgO-CaS completely, then reduced the formations of voids between inclusions and steel matrix. Finally, the fatigue life was raised obviously from 9.8 × 104 cycles to 1.5 × 107 cycles.

The hot-rolled 60Si2MnA spring steels were obtained by different cooling rates after finish rolling through dynamic thermal simulation test, and followed by some quenching-tempering treatment. The relationship among the condition of proeutectoid ferrite precipitation, microstructures and mechanical properties of hot-rolled spring steel, and heredity in microstructure and mechanical properties during heat treatment was investigated comprehensively. Results showed that as the cooling rate increased from 0.5 °C/s to 5 °C/s, the bulk content of proeutectoid ferrite decreased from 24% to 2%, pearlitic colony size and interlamellar spacing also decreased, the reciprocal of them both followed a linear relationship with the reciprocal of proeutectoid ferrite content. So the microstructure became finer and more uniform, the tensile strength and percentage of area reduction of hot-rolled spring steel both increased. During heat treatment, the average grain size and standard deviation of its normal distribution both depended linearly on the content of proeutectoid ferrite. Therefore, the austenite grain, quenched microstructure and tempered troostite all also became finer and more uniform. Finally, the tensile strength and percentage of area reduction of spring steel after heat treatment also increased, and the tensile fracture of spring steel transformed from the intergranular fracture to the cleavage and dimple fracture.