形变组织对水电用高强度贝氏体钢再加热奥氏体晶粒长大的影响

对某水电用800 MPa调质贝氏体高强钢进行了热变形-热处理晶粒长大的实验室联合试验。采用Gleeble-3500热力模拟试验机对钢试样进行不同工艺热压缩变形后冷却至室温,随后对试样进行模拟淬火再加热,在900～1200℃不同温度和保温时间条件下奥氏体化,研究热变形组织的差异对重新奥氏体化晶粒长大的影响规律。结果表明,不同应变速率(0.01～10 s^-1)、变形温度(900～1150℃)和60%工程应变下,试验钢获得的变形组织大致可分为3类：带有明显变形特征的组织、均匀细小的完全再结晶组织和已长大粗化的再结晶组织。3类组织再加热过程中其晶粒长大趋势基本相同,起始晶粒尺寸越大则最终奥氏体晶粒尺寸越大;但在950℃等温时,带有明显变形特征组织的变形试样奥氏体晶粒先缓慢长大后又迅速长大粗化。经评估验证,所建立的Sellars模型、Beck模型和Hillert模型晶粒长大动力学方程对于试验钢的奥氏体晶粒长大行为均有比较满意的预测效果。3类变形组织对应的Hillert模型及Sellars模型中奥氏体长大激活能基本相同,说明同一成分钢种的初始组织的差异并未显著影响晶粒长大机制...     

Electrochemical properties of nano-sized Fe2O3-loaded carbon as a lithium battery anode

Nano-sized Fe₂O₃-loaded carbon material was prepared by loading Fe₂O₃ on carbon using a chemical method. Fe(NO₃)₃ was impregnated on carbon in an aqueous solution, and the mixture was dried and then calcined for 1 h at 400 °C in flowing Ar. Transmission electron microscopy (TEM) coupled with X-ray diffraction measurements revealed that small Fe₂O₃ particles (a few tenths of nanometers) were distributed on the carbon surface. The obtained nano-sized Fe₂O₃-loaded carbon material acted as an anode in a Li cell. High charge capacities of over 1000 mAh g⁻¹ (reduction of Fe₂O₃) in the first charge process suggested that Fe³⁺ in Fe₂O₃ was electrochemically reduced to Fe⁰. Investigation of the charge material by X-ray photoelectron spectroscopy (XPS) confirmed that Fe³⁺ is reduced to Fe⁰. Nano-sized Fe₂O₃-loaded acetylene black (AB), which, due to the larger surface area of AB, gave a greater distribution of nano-sized Fe₂O₃ particles than graphite, provided a larger capacity than nano-sized Fe₂O₃-loaded graphite.     

First-principles rational design of M-doped LiBH4(010) surface for hydrogen release: Role of strain and dopants (M=Na,K, Al,F, or Cl)

To overcome the important challenges of facilitating dehydrogenation in the complex metal hydride, LiBH₄, the structural and chemical effects were considered using the strain (−3% − +3%) and five dopants (M = Na, K, Al, F, or Cl). The desorption energies of a hydrogen molecule decreased with increasing tensile strain on the LiBH₄(010) surface. The tensile strain was useful for promoting the dehydrogenation process by weakening the B-H interactions. Among the dopants examined, the most favorable dopant to enhance dehydrogenation was Al. The ranking of dopants for hydrogen release was Al > Cl > F > Na > K. Remarkably, codoping of Al and Cl was more effective for hydrogen release than the single doping of Al or Cl with the lowest hydrogen desorption energy. These methods that destabilize metal hydrides are practical for tuning the hydrogen release of LiBH₄ hydrides. These studies will provide efficient means for designing excellent hydrides for hydrogen release.     

基于生物免疫学方法的泛在电力物联网安全技术

由于泛在电力物联网融入了社会的不可预知因素,导致互联环境复杂多样,终端设备接入类型与数量激增,时刻面临网络攻击和非安全数据入侵等安全隐患。因此,已有的安全检测与防护技术不再完全适用于如今的泛在电力物联网,文中从生物免疫学新视角探讨了泛在电力物联网安全技术。首先,类比病原体入侵生物体时免疫系统的免疫过程,阐述了生物免疫学与泛在电力物联安全防护的关联;其次,分析了感知层、网络层、平台层和应用层面临的安全挑战,并基于免疫学归纳了抗原识别、免疫响应和免疫记忆3方面的关键技术;最后,构想了泛在电力物联网全方位智能联动的安全免疫体系,并对研究方向进行了展望。     

红沿河核电站凝结水精处理系统的启动与运行

凝结水精处理系统（ATE）及其良好运行状态对核电站安全运行至关重要。以红沿河核电站3、4号机组ATE系统为例,对比机组首次启动和正常启动2种工况下ATE出水水质和制水量;介绍混床树脂完全分离的方法,给出树脂再生的重要控制点;对调试期间所遇问题进行分析,给出防范措施。经调试,红沿河核电站3、4号机组ATE运行良好,出水氢电导率、Na⁺质量浓度和SiO₂质量浓度分别为0.08 μS/cm、0.10 μg/L和1.91 μg/L,阳床和混床制水量分别为1.2×10⁵ t和4.4×10⁵ t ;树脂分离和再生的效果良好,阴树脂在阳树脂层内的体积分数小于0.08%,阳树脂在阴树脂层内的体积分数小于0.07%;ATE运行期间,蒸汽发生器排污水中Na⁺、Cl^-和SO₄^2-的浓度符合水化学规范。     

New oxadiazole complex with bipolar ligand for organic light-emitting devices

New oxadiazole complex with bipolar ligand, Zn(POTPA)₂, was designed and synthesized, and used as an emitter material in single-layer organic electroluminescent (EL) devices (OLED). The UV absorbance of Zn(POTPA)₂ is caused by electron π–π^? transition. Zn(POTPA)₂ exhibited strong blue luminescence in solution and film. Compared with triphenylamine and 2,5-diphenyl-1,3,4-oxadiazole, cyclic voltammograms exhibited that Zn(POTPA)₂ has bipolar properties, and the optical band gap energy, Eg, calculated based on the cyclic voltammograms is nearly equal to that deduced from the absorption spectrum. Single-layer device with the structure of ITO/Zn(POTPA)₂/Mg:Ag were fabricated and blue electroluminescence was observed with a maximum luminance of 271 cd/m² and efficiency of 0.46 cd/A.     

Comparative study on pyrolysis characteristics and kinetics of oleaginous yeast and algae

The pyrolysis processes of oleaginous yeast and algae were studied and compared using a non-isothermal thermogravimetric analyzer at heating rates of 10–50 °C/min, and the most probable mechanism function and kinetic analyses of the main stage of pyrolysis were carried out by the Popuse method, Starink method, and Fridemen method. The main pyrolysis stage of the samples could be described by the Jander equation and Z–L–T equation and the activation energy of the three biomass was 108–117, 107–121 and 93–108 kJ/mol, respectively. For the three kinds of biomass, the DTG curves were divided based on the four pseudo-components by performing Gaussian fitting which are carbohydrates, proteins, lipids, others, and the weight coefficients of them could be identified. The activation energy of each pseudo-component was obtained in the range of 58.36–140.44 kJ/mol by the Kissinger method. The four-pseudo-component model based on Gaussian fitting provides effective data for the design of oleaginous yeast and algae thermal decomposition systems and the kinetic analysis of the pyrolysis process.     

Conducting polymer artificial muscles

The application of conducting polymers for the direct conversion of electrical energy to mechanical energy in electromechanical actuators is analyzed using theoretical and experimental results. Basic principles of operation, predicted performance advantages and disadvantages, comparisons with natural muscle, evaluations of initial device demonstrations, and methods for improving device performance are provided. The very high predicted work densities per cycle, force generation capabilities, and power densities provide major advantages compared with piezoelectric polymers – as do the low operation voltages. These advantages are countered by cycle life and energy conversion efficiency limitations, as well as the need to use microelectrodes in order to achieve very high rates. Hydrostatic devices and extensional devices that provide either in-phase or out-of-phase electrode deformations are considered. Special types of conducting polymer actuators are also proposed, including photo-powered, chemically powered and self-powered actuators, which provide novel methods for assembling complex microstructures. Novel methods are described for actuator fabrication, such as ‘redox poling’, wherein anode, cathode and separating electrolyte layers are generated from a film in a single redox step. New actuator compositions are also proposed for obtaining improved performance, such as conjugated carbon phases having conjugation in either two or three dimensions. Finally, conducting polymer actuators based on double-layer charging are proposed which are predicted to provide increased energy efficiency and cycle life compared with the faradaic actuators.     

基于智能电能表数据三相不平衡治理的研究与实践

国网吉林电力城网和农网有约11万公变台区,三相不平衡对电压合格率、线损、变压器负载能力及设备健康水平等指标影响较大,在传统的三相负载不平衡调整方法中,一线员工常常根据运行数据,凭借经验解决现场问题,由于没有科学的调整方法,效果往往不佳。国网吉林电力已经实现智能电能表全覆盖,充分利用智能电能表的非计量数据和相关应用技术,创新提出基于电力线窄带载波同步过零技术,开展低压客户自动相位识别技术研究,实现对客户所在相位的判别,运用贪心算法智能生成三相不平衡治理策略,开发简单易用的智能辅助工具,为一线员工提供解决实际问题的有效技术手段,在保证各项指标的基础上,进一步提高供电可靠性和公司经济效益。     

基于MapReduce的输电监测数据智能检索模型

随着新型电力系统发展,输电监测文本数据呈现出体量大、增速快等特点,且因行业数据传输协议私有化,导致数据检索性能低,影响输电线路实时决策分析。因此提出了基于MapReduce的输电监测数据智能检索模型。首先,改进了SimHash算法,实现输电线路在线监测文本数据检索向量的高效提取。并引入多属性决策以及综合评分机制,实现目标数据的精准检索,提升数据的检索精度及查全率。其次,针对数据体量大、增速快的特点,设计了基于MapReduce的电力数据检索模型。最后,通过电网实例对比分析,验证了所提方法的检索精度、查全率及检索效率。