Young’s modulus evolution during heating,re-sintering and cooling of partially sintered alumina ceramics

The Young modulus of partially and fully sintered alumina ceramics, obtained by firing to different temperatures (range 1200–1600°C), has been determined via impulse excitation, and the evolution of Young’s modulus of partially sintered alumina with temperature has been monitored from room temperature to 1600°C. As expected, the room-temperature Young modulus of the partially sintered materials is lower than all theoretical predictions. With increasing temperature Young’s modulus decreases, until the original firing temperature is exceeded and sintering (densification) continues, resulting in a steep Young’s modulus increase. During heating and cooling the temperature dependence obeys a master curve for alumina, unless the temperature of the original firing is excessively low.     

Designing amino-based ionic liquids for improved carbon capture: One amine binds two CO2

Generally, amine group captures CO₂ according to 2:1 or 1:1 stoichiometry. Here, we report a kind of improved carbon capture using amino-functionalized ionic liquids (ILs) through 1:2 stoichiometry. A serial of amino-functionalized ILs various with basicity and steric hindrance of anion were designed, prepared, and applied in CO₂ capture. Through a combination of absorption experiment, quantum chemical calculation, spectroscopic investigation and calorimetric method, the results indicated that one amine group could bind two CO₂ through proton transfer (PT) process and intramolecular hydrogen bond formation, which leading to enhanced capacity that breaks through equimolar. The basicity and steric hindrance of anion play a significant role in promoting amine group to capture two CO₂. [P₆₆₆₁₄]₂[Asp] with dual anion was further designed and synthesized to promote PT process, which showed high capacity of 1.96 mol/mol IL at 30°C and 1 atm as well as excellent reversibility. © 2018 American Institute of Chemical Engineers AIChE J, 65: 230–238, 2019     

Style-Controllable Speech-Driven Gesture Synthesis Using Normalising Flows

Automatic synthesis of realistic gestures promises to transform the fields of animation, avatars and communicative agents. In off-line applications, novel tools can alter the role of an animator to that of a director, who provides only high-level input for the desired animation; a learned network then translates these instructions into an appropriate sequence of body poses. In interactive scenarios, systems for generating natural animations on the fly are key to achieving believable and relatable characters. In this paper we address some of the core issues towards these ends. By adapting a deep learning-based motion synthesis method called MoGlow, we propose a new generative model for generating state-of-the-art realistic speech-driven gesticulation. Owing to the probabilistic nature of the approach, our model can produce a battery of different, yet plausible, gestures given the same input speech signal. Just like humans, this gives a rich natural variation of motion. We additionally demonstrate the ability to exert directorial control over the output style, such as gesture level, speed, symmetry and spacial extent. Such control can be leveraged to convey a desired character personality or mood. We achieve all this without any manual annotation of the data. User studies evaluating upper-body gesticulation confirm that the generated motions are natural and well match the input speech. Our method scores above all prior systems and baselines on these measures, and comes close to the ratings of the original recorded motions. We furthermore find that we can accurately control gesticulation styles without unnecessarily compromising perceived naturalness. Finally, we also demonstrate an application of the same method to full-body gesticulation, including the synthesis of stepping motion and stance.     

应用变频器技术实现SO2风机节能改造

铜目前,硫酸车间制酸一系列共有三台SO2风机,这三台风机均采用液力耦合器的调速方式,这种方式可以实现无极调速,但是存在着传动效率低,耗能大的缺点,并且这三台风机均已使用20年以上,处于设备的中晚期,工作效率已大大降低。目前行业内,均采用先进的变频调速方式。使用变频器来控制风机的转速,可以极大的节省电能,尤其是在低负荷情况下,可以实现低转速运转,大大提高硫酸系统的综合能耗指标。     

换热网络优化中换热单元生成频次的影响分析及策略改进

换热单元的生成频次对换热网络优化有直接的影响，分析其机理可以指导求解算法的改进。本文采用节点非结构模型及强制进化随机游走算法，通过设置不同的换热单元生成概率与生成个数以改变换热单元的生成频次，观察并记录个体在优化过程中产生的年综合费用变化情况。发现不同生成频次下整型变量和连续变量的相对优化频率发生了变化，从而改变了整体优化过程，并且与个体当前优化状态不适应的生成频次会造成相对优化频率不平衡、优化结果较差。基于此，本文提出了一种具有生成参数动态调节策略的换热单元生成方式，在优化过程中根据个体状态实时调整换热单元的生成概率与生成个数，平衡整型变量与连续变量的相对优化频率。最后，采用15SP、10SP和20SP算例进行验证，换热网络的年综合费用较文献结果分别下降了1.06%、0.16%、0.68%，验证了该策略使得换热单元的生成频次更为合理，有效地提高了算法的优化效率。     

Low Frequency Electromagnetic Casting of 2195 Aluminum-Lithium Alloy and Its Effects on Microstructure and Mechanical Properties

In this study,the low frequency electromagnetic casting(LFEC) technology was adopted to fabricate 2195 Al-Li alloy.The microstructure and solid solubility of as-cast 2195 alloys,as well as the second phase precipitation and tensile properties after aging,were investiagated and compared with the counterpart direct chill casting 2195 alloy.Our results indicate that LFEC can significantly improve the microstructure and metallurgical quality of as-cast alloy,and increase the number density of θ'(Al_2 Cu) and T_1(Al_2 CuLi) phases during aging treatment due to the enhanced solubilities of alloying elements.The tensile properties of 2195 aged alloy cast by LFEC were hence improved evidently.     

High-performance oxygen transport membrane reactors integrated with IGCC for carbon capture

Precombustion carbon capture is an effective strategy to reduce large-scale CO₂ emissions, which is mainly used in the area of integrated gasification combined cycle (IGCC) power plants. Oxygen transport membranes (OTMs) were suggested as the air separation unit to produce high purity oxygen for the gasifier. However, the improvement in efficiency was limited. Here, a new IGCC process is reported based on a robust OTM reactor, where the OTM reactor is used behind the coal gasifier. This IGCC-OTM process fulfills syngas oxidation, H₂ production, and carbon capture in one unit, thus a significant decrease of the energy penalty is expectable. The membrane reactor does not use noble metal components, and exhibits high hydrogen production rates, high hydrogen separation factor (10³–10⁴), and stable performance in a gas mixture mimicking real syngas compositions from a coal gasifier with H₂S concentrations up to 1,000 ppm.     

低截止频率多倍频程高增益对跖Vivaldi天线北大核心CSCD

针对传统对跖Vivaldi天线的最低截止工作频率较高、增益较低和方向性较差的问题,文中设计了一种新型超宽带对跖Vivaldi天线。融合运用辐射极板开矩形斜槽、加载吸收电阻和寄生矩形贴片等一系列电磁调控措施,扩展了天线的低频工作带宽;采取在天线极板间加载椭圆寄生贴片的技术方式大幅提高了天线的方向性和辐射增益。最后给出了天线的设计流程,从电场分布和表面电流分布的角度揭示了天线的微观工作机制。仿真和实测结果表明:天线的工作频带为0.85~16 GHz(近20倍频程),相对带宽达180%,在3 GHz以上频段增益均超过10 dBi,并且具有较好的端射方向性,在超宽带无线通信、雷达探测、电子对抗和遥感遥测等领域具有广泛的应用前景。     

Fourier transform ion cyclotron resonance mass spectrometry at the true cyclotron frequency

Ion cyclotron resonance (ICR) cells provide stability and coherence of ion oscillations in crossed electric and magnetic fields over extended periods of time. Using the Fourier transform enables precise measurements of ion oscillation frequencies. These precisely measured frequencies are converted into highly accurate mass-to-charge ratios of the analyte ions by calibration procedures. In terms of resolution and mass accuracy, Fourier transform ICR mass spectrometry (FT-ICR MS) offers the highest performance of any MS technology. This is reflected in its wide range of applications. However, in the most challenging MS application, for example, imaging, enhancements in the mass accuracy of fluctuating ion fluxes are required to continue advancing the field. One approach is to shift the ion signal power into the peak corresponding to the true cyclotron frequency instead of the reduced cyclotron frequency peak. The benefits of measuring the true cyclotron frequency include increased tolerance to electric fields within the ICR cell, which enhances frequency measurement precision. As a result, many attempts to implement this mode of FT-ICR MS operation have occurred. Examples of true cyclotron frequency measurements include detection of magnetron inter-harmonics of the reduced cyclotron frequency (i.e., the sidebands), trapping field-free (i.e., screened) ICR cells, and hyperbolic ICR cells with quadrupolar ion detection. More recently, ICR cells with spatially distributed ion clouds have demonstrated attractive performance characteristics for true cyclotron frequency ion detection. Here, we review the corresponding developments in FT-ICR MS over the past 40 years.