Physicochemical characteristics,antioxidant capacity and thermodynamic properties of purple-fleshed potatos dried by radio frequency energy

Abstract

The impacts of using radio frequency (RF) energy to dry purple-fleshed potatoes were investigated and compared to infrared radiation (IR) and microwave (MW) drying techniques. The gelatinization rate, color, flavor, morphological, and structural characteristics, thermodynamic properties, as well as antioxidant capacity were examined. The results indicated that the drying time of RF (70?min) and MW (21?min) were shorter than IR (105?min). The gelatinization ratio of MW, RF, and IR were 94.4?±?2.0, 88.3?±?1.4, and 64.5?±?1.1%, respectively. The degree of crystallization of purple-fleshed potato powder decreased with all three drying methods. RF-dried potatoes were able to retain higher polyphenols (loss rate: 4.3%), total anthocyanin (3.7%), and total flavonoid content (35.1%), whereas IR showed the lowest retention. The content of polyphenols also decreased significantly. Furthermore, after RF heating, the scavenging of free radicals was higher compared to MW and IR.     

天然气新型气液分离器性能试验研究

为了解决天然气含有饱和水汽和少量烃降低输气效率、堵塞管线和设备等问题,利用旋风子、稳流元件、叶栅式分离元件、折流板式分离元件组合成新型天然气分离器。利用相位多普勒粒子分析仪对新型天然气分离器进出口粒子粒径与液态水含量的进行对比测试,以研究新型分离器的分离效率。结果表明:新型分离器具有良好的气液分离作用;在流量为10～64 m~3/h时,分离器的分离效率成抛物线形式,在33 m~3/h时分离器的分离效率降到最低值95.16%,主要原因是流量在33 m~3/h时,试验气液混合不均匀,导致内部流态紊乱,以至于试验测得分离效率相对偏低;在流量为10 m~3/h时分离器分离效率最高,为99.29%;分离器对该进口条件的气体中雾状液粒有较高的分离作用,且可以明显降低分离器出口气体中液粒的平均粒径;从进口到气相出口压力逐渐降低,总压降为950 Pa;流动区域速度梯度大不利于气液相分离,流动掺混会导致分离效率降低。     

推土机智能化控制技术的现状与发展趋势

随着电子信息技术的进步,推土机正在向自动化、智能化方向发展。从行走系统智能控制、工作装置智能控制、故障诊断等方面介绍了推土机智能化控制技术的现状,从数字化机械施工、工作装置智能引导与自动控制、互联网大数据共享、机群智能化控制管理等方面分析了推土机智能化控制技术的发展趋势。     

一种下肢运动意图识别算法性能实时测评系统* .txt

摘要：对腿部运动意图识别算法的实时性能进行综合可靠的评价是实现下肢假肢灵活稳定控制的前提。提出一种逐层分级的基于下肢运动意图识别算法的实时测评方法，对算法的可靠性、稳定性以及运动意图识别速度进行综合评价。利用开发的运动意图识别算法评测系统，对基于肌电信号源和机械信号源的两种运动意图识别算法进行了实时性能测试，发现肌电信号源的算法识别时间大于机械信号源算法，但是其算法稳定性优于机械信号源算法。进一步地，还利用该评测系统有效地区分出正常识别策略与异常识别策略，发现正常策略的动作识别稳定系数比异常策略高25%左右。因此，所提的基于下肢运动意图识别算法的实时测评方法，能够对不同信号源算法以及不同识别策略的实时性能进行有效评价，为智能下肢假肢控制系统开发提供可供参考的测试平台。 .txt     

浅谈船用主机使用低硫燃油面临的挑战与应对措施

介绍了低硫燃油和传统的船用高硫燃油在化学成分和物理特性方面存在的诸多不同;指出:IMO2020限硫令对船舶运营带来了很大的挑战。基于两大主机制造商的相关文件和实际服务经验，归纳总结了船用主机使用低硫燃油运营时应注意的事项及应对措施，为船舶安全稳定运营提供参考。     

Zone model predictive control for pressure management of water distribution network

In the water distribution network (WDN), although the water demand of the node is changing constantly, the water quantity and water pressure of the node need to be met at each moment. To realize energy saving and consumption reduction, it is proposed to control the nodal water head of WDN in an appropriate narrow range. The frequent large fluctuation of the water demand, which may lead the water pressure exceed the expected range, increases the difficulty of the zone control. To realize optimized WND control, a novel zone predictive control is proposed, where two switching cases are considered. The switching condition is whether there are feasible solutions to keep the pressure within the expected region over the prediction horizon. When the condition is satisfied, the controller minimizes the variation of inputs with constraints of pressure range for ensuring the tank level staying within the expected zone and obtaining optimal economic cost. When the current pressure is out of the expected region or the condition is not satisfied due to the large variation of water demand, a reference trajectory of outputs is introduced, which is combined with the inputs as an optimization variable, and the constraints of expected zone are moved from the output to the introduced reference trajectory. Through minimizing the distance between reference trajectory and output, the controller will keep the tank level from deviating too far from the expected zone and will drive the tank level rapidly into the expected zone once the tank level exceeds the expected range. An application of the proposed zone MPC to WDN in Shinan District of Shanghai is given to illustrate its effectiveness.     

Flame Retardancy and Mechanical Properties of Bio‐Based Furan Epoxy Resins with High Crosslink Density

This work outlines an interesting approach to bioepoxy resins from sustainable 2,5‐bis((oxiran‐2‐ylmethoxy)methyl)furan (BOF). The 3,3′‐diamino diphenyl‐sulfone (33DDS) and 4,4′‐diamino diphenyl‐sulfone (44DDS) are employed as hardeners. For comparison, petro‐based networks from diglycidyl ether of bisphenol A (DGEBA) are developed as well. The systematic analyses suggest that the BOF/DDS networks show higher crosslink densities and mechanical properties than DGEBA/DDS thermosets. Remarkably, an attractive multilayer tubular microstructure is fabricated in the BOF/44DDS thermosets, and it greatly enhances the mechanical performance. Apart from that, BOF/DDS composites exhibit excellent flame retardancy. Especially, for BOF/44DDS, the self‐extinguishment happens in 7 s. The fire retardant mechanism confirms that a low heat release rate and heat release capacity as well as a compact char layer occur in the pyrolysis of BOF/DDS. Thus, the BOF/DDS exhibits superior performance over its DGEBA counterparts and meets a wide variety of requirements in engineering.     

高速激光热丝钎焊表面成形质量的控制

高速激光钎焊会引起熔池流动紊乱导致焊缝成形质量恶化,从而限制了其在汽车制造领域的应用。通过正交试验研究了高速下激光功率、送丝角度等工艺参数对焊缝成形质量的影响,发现焊缝成形质量随激光功率增加和送丝角度减小而提升。激光功率是通过影响熔池获得的热输入,从而影响熔池表面扰动的铺展来影响焊缝成形质量的。送丝角度是通过影响焊丝送入熔池的位置,从而影响焊丝对熔池的扰动强度和扰动的铺展速度来影响焊缝成形质量的。采用正交试验获得的最优工艺参数组合进行试验,获得了表面光滑平整无缺陷的高质量焊缝,为激光钎焊在高速下的应用发展奠定了基础。     

反应磁控溅射(CrMoTaNbVTi)N多主元薄膜的微观组织与机械性能研究

本文采用直流反应磁控溅射方法，通过溅射（CrMoTaNbV）镶嵌靶和纯Ti靶制备了(CrMoTaNbVTi)N多主元氮化物薄膜。研究了不同氮气流量比RN对(CrMoTaNbVTi)N薄膜的微观结构、力学性能和摩擦学性能的影响。结果表明，当RN=0% 和10%时薄膜为简单的体心立方结构，当RN=20%、30% 和40%时为简单的面心立方结构。随着氮气流量比RN的增大，表面颗粒逐渐减小，断面柱状晶更为致密，同时(CrMoTaNbVTi)N薄膜的残余应力、膜基结合力、硬度和弹性模量逐渐增大，且当RN=40%时达到最大值，分别为-3.3 GPa, 352 mN, 25.6±1.2 GPa 和 278.8±11.2 GP。RN =40%制备的氮化物薄膜具有最小的比磨损率，相较合金薄膜降低了约1个数量级，表现出优异的耐磨损性能。     

Self-activated persistent luminescence from Ba2Zr2Si3O12 for information storage

Till now, many doped persistent luminescence (PersL) phosphors have been investigated and found various applications in such as bioimaging, photocatalysis and information storage, but introducing PersL emitters into a proper host is mostly complex. In this research, a self-activated PersL phosphor Ba₂Zr₂Si₃O₁₂ (BZSO) is prepared by solid state reaction. By adding NH₄Cl, the self-activated PersL intensity is evidently enhanced. The trap depths and concentrations are examined by thermoluminescence spectra. Meanwhile, Bi³⁺ ions are introduced into BZSO and show wide band photoluminescence (PL) from 300 to 600 nm. Moreover, the PL of Bi³⁺ is tunable under excitation by 265-350 nm lights. Furthermore, as a proof-of-concept design, we designed a patterned quick response (QR) code based on the self-activated PersL of BZSO, and the information of “South China University of Technology (SCUT)” can be read out by the code scanning technology. Bi³⁺-doped BZSO phosphors are suggested to provide potential applications in information storage by its self-activated PersL, and to excite researchers to study the tunable PL in Bi³⁺-doped phosphor.