Dichlorinated Dithienylethene-Based Copolymers for Air-Stable n-Type Conductivity and Thermoelectricity

Two donor–acceptor (D–A) polymers are obtained by coupling difluoro- and dichloro-substituted forms of the electron-deficient unit BDOPV and the relatively weak donor moiety dichlorodithienylethene (ClTVT). The conductivity and power factors of doped devices are different for the chlorinated and fluorinated BDOPV polymers. A high electron conductivity of 38.3 and 16.1 S cm⁻¹ are obtained from the chlorinated and fluorinated polymers with N-DMBI, respectively, and 12.4 and 2.4 S cm⁻¹ are obtained from the chlorinated and fluorinated polymers with CoCp₂, respectively, from drop-cast devices. The corresponding power factors are 22.7, 7.6, 39.5, and 8.0  µ W m⁻¹ K⁻², respectively. Doping of PClClTVT with N-DMBI results in excellent air stability; the electron conductivity of devices with 50 mol% N-DMBI as dopant remained up to 4.9 S m⁻¹ after 222 days in the air, the longest for an n-doped polymer stored in air, with a thermoelectric power factor of 9.3  µ W m⁻¹ K⁻². However, the conductivity of PFClTVT-based devices can hardly be measured after 103 days. These observations are consistent with morphologies determined by grazing incidence wide angle X-ray scattering and atomic force microscopy.     

A novel inverse procedure for load identification based on improved artificial tree algorithm

This paper presents an accurate and effective method, namely, the improved artificial tree algorithm based on the Green’s kernel function method (IAT-GKFM), to identify the load in time domain. The forward problem of load identification is constructed by using the Green’s kernel function method. The forward problem is discretized using the time domain Galerkin method, where a matrix form for load identification is formed. The IAT algorithm is proposed to solve the inverse multi-dimensions problem in the inverse stage, which aims to minimize the measuring dispersion between the calculated response and the actual response. Several numerical examples are conducted. It is demonstrated that the IAT with high performance can provide more optimum results than those of other compared algorithms. Using this optimized strategy, the loads acting on a simple plate and a vehicle roof are reconstructed successfully. The superiority of IAT-GKFM may motivate the improvement of the other inverse problems.

     

多组元钛合金电子束冷床炉熔炼挥发规律研究

利用电子束冷床炉(EB炉)一次熔炼制备TC4、Ti6242、TA15钛合金铸锭,采用Langmuir定律对熔炼过程中Al、Sn、Zr、Mo等元素的挥发规律做了简要的数值分析,并与实际挥发规律进行了对比分析。结果表明:EB炉熔炼TC4、Ti6242、TA15钛合金过程中,Al元素在3种合金中的挥发率有所不同,挥发率由大到小顺序为TC4>Ti6242>TA15;Al元素是TC4钛合金中主要的挥发元素;Ti6242钛合金中,Al、Sn元素之间存在联合挥发的问题;TA15钛合金中,Al、Zr元素之间亦存在联合挥发的问题,Al元素带动了Zr元素(难挥发元素)的挥发。     

Multiple clusterings of heterogeneous information networks

Machine Learning - Traditional clustering algorithms focus on a single clustering result; as such, they cannot explore potential diverse patterns of complex real world data. To deal with this...     

An elite-guided hierarchical differential evolution algorithm

Applied Intelligence - Population structure has an impact on the performance of metaheuristic algorithms. To better improve the performance of differential evolution (DE), an elite-guided...     

免涂装低屈强比耐候桥梁钢的开发应用

通过优化成分设计以及轧制、热处理工艺,成功开发出8 ～ 80 mm厚度的免涂装低屈强比耐候桥梁钢.针对免涂装低屈强比耐候桥梁钢的工艺、金相组织和焊接性进行分析研究,结果表明:耐候桥梁钢Q345qENH～ Q690qENH的屈强比可以通过适量铁素体+不同形态贝氏体组织配比进行调控,使低温冲击韧性、低屈强比和耐候性同时得到保证,实现了优良的强度、冲击韧性和可焊性.     

Functionalized graphene oxide nanosheets with unique three-inone properties for efficient and tunable antibacterial applications

Developing antibiotics-independent antibacterial agents is of great importance since antibiotic therapy faces great challenges from drug resistance.Graphene oxide(GO)is a promising agent due to its natural antibacterial mechanisms,such as sharp edgemediated cutting effect.However,the antibacterial activity of GO is limited by its negative charge and low photothermal effect.Herein,the amino-functionalized GO nanosheets(AGO)with unique three-in-one properties were synthesized.Three essential properties(positive charge,strong photothermal effect,and natural cutting effect)were integrated into AGO.The positive charge(30 mV)rendered AGO a strong interaction force with model pathogen Streptococcus mutans(330 nN).The natural cutting effect of 100 ng·mL^-1AGO caused 27%loss of bacterial viability after incubation for 30 min.Most importantly,upon the near-infrared irradiation for just 5 min,the three-in-one properties of AGO caused 98%viability loss.In conclusion,the short irradiation period and the tunable antibacterial activity confer the three-in-one AGO a great potential for clinical use.     

The Ductility Variation of High-Pressure Die-Cast AE44 Alloy: The Role of Inhomogeneous Microstructure

In the study, the through-thickness microstructure and its effects on the ductility and strain heterogeneity in high-pressure die-cast AE44 alloy were investigated. The results show that the studied alloy had a gradient microstructure, where two fine-grained skins sandwiched a core with coarse externally solidified crystals (ESCs) embedded in fine grains. In the core, where porosity concentrated, the ultra-coarse ESCs with sizes up to 600 μm were observed. A great amount of Al₁₁RE₃ phase, as the predominant intermetallic phase, was distributed in homogeneously through the thickness. High-resolution digital image correlation (DIC) measurement coupled with electron backscatter diffraction (EBSD) was employed to reveal the deformation inhomogeneity and its root cause. It was found that considerable strain localization mainly appeared in the ultra-coarse ESCs with soft orientation for basal slip and the regions where porosity appeared. Unlike the yield strengths and ultimate tensile strengths, the elongations showed a significant variation. Not only defects but also the ultra-coarse ESCs were the primary factors responsible for the variation in ductility.

     

酸性服役管线管BNS力学及耐腐蚀性能研究

文章介绍了包钢钢管公司酸性服役管线管BNS成分设计要求,对材料的拉伸性能、冲击性能、组织以及耐腐蚀性能进行了检测和分析,正火处理后,材料具有良好的力学性能和抗腐蚀性能.试验结果表明,设计的BNS完全能满足酸性服役条件下管线管性能要求.