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41.
The structural diversity of polyphenols and the inherent limitations of current extraction techniques pose a challenge to extract polyphenols using a simple and green method. Hence, in this study, a method was developed to simultaneously fractionate multiple classes of polyphenols by only varying ethanol-water solutions. Honeybush tea, which is rich in polyphenols, was selected as a model for this study. Solvent extraction followed by solid-phase extraction (SPE) was developed to obtain a polyphenol-rich fraction from six honeybush samples. Based on a gradient elution programme (10%, 30%, 50%, 70% and 90% (v/v) ethanol-water solution) of SPE, the Strata X cartridge showed a better recovery of most targeted polyphenols under 0.9 mL of the drying volume and 1 mL min−1 of the dispensing speed. The elution programme for fractionating most polyphenols was as follows: single elution with 50% ethanol, followed by twice elution with 70% ethanol. The antioxidant capacity was used to analyse the differences among the polyphenol-rich fractions from six honeybush samples. Principal component analysis (PCA) revealed that unfermented C. genistoides (GG) has the greatest antioxidant capacity among the honeybush species studied. Additionally, mangiferin, isomangiferin and vicenin-2 were the main contributors to the antioxidant capacity in six honeybush fractions according to the correlation study.  相似文献   
42.
The slight-alkalization of generator internal cooling water (GICW) is widely used to inhibit the corrosion of hollow copper conductor and thereby ensure the safe operation of the generator. CO2 inleakage is increasingly identified as a potential security risk for GICW system. In this paper, the influence of CO2 inleakage on the slight-alkalization of GICW was theoretically discussed. Based on the equilibriums of the CO2-NaOH-H2O system, CO2 inleakage saturation was derived to quantify the amount of the dissolved CO2 in GICW. This parameter can be directly calculated with the measured conductivity and the [Na+] of GICW. The influence of CO2 inleakage on the slight-alkalization conditioning of GICW and the measurement of its water quality parameters were then analyzed. The more severe the inleakage, the narrower the water quality operation ranges of GICW, resulting in the more difficult the slight-alkalization conditioning of GICW. The temperature calibrations of the conductivity and the pH value of GICW show non-linear correlations with the amount of CO2 inleakage and the NaOH dosage. This study provides insights into the influence of CO2 inleakage on the slight-alkalization of GICW, which can serve as the theoretical basis for the actual slight-alkalization when CO2 inleakage occurs.  相似文献   
43.
The realization of liquid metal-based wearable systems will be a milestone toward high-performance, integrated electronic skin. However, despite the revolutionary progress achieved in many other components of electronic skin, liquid metal-based flexible sensors still suffer from poor sensitivity due to the insufficient resistance change of liquid metal to deformation. Herein, a nacre-inspired architecture composed of a biphasic pattern (liquid metal with Cr/Cu underlayer) as “bricks” and strain-sensitive Ag film as “mortar” is developed, which breaks the long-standing sensitivity bottleneck of liquid metal-based electronic skin. With 2 orders of magnitude of sensitivity amplification while maintaining wide (>85%) working range, for the first time, liquid metal-based strain sensors rival the state-of-art counterparts. This liquid metal composite features spatially regulated cracking behavior. On the one hand, hard Cr cells locally modulate the strain distribution, which avoids premature cut-through cracks and prolongs the defect propagation in the adjacent Ag film. On the other hand, the separated liquid metal cells prevent unfavorable continuous liquid-metal paths and create crack-free regions during strain. Demonstrated in diverse scenarios, the proposed design concept may spark more applications of ultrasensitive liquid metal-based electronic skins, and reveals a pathway for sensor development via crack engineering.  相似文献   
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现代学徒制是一项深化产教融合、校企合作的育人机制,是创新技术技能人才的现代培养模式.山西铁道职业技术学院与山西安泰控股集团有限公司深度合作开展山西省现代学徒制试点项目,合作目的之一是培养企业煤化工专业人才.学校教师结合学生(员工)在企业车间岗位上的技能知识,系统地讲授煤化工专业课程"煤质分析及煤化工产品检验"理论知识,同时针对企业员工日常学习思想政治知识较少的实际,润物细无声地加入思政元素,实现专业知识与实践技能相结合,技能知识与思政教育相融合,真正培养知识型、技能型、创新型高素质技能人才,努力构建职业教育产业发展命运共同体.  相似文献   
46.
安全仪表功能(SIF)回路是为了降低特定场景的安全风险而设置的,定级报告中SIF回路的功能描述是工艺设计的完整逻辑要求,包含关键动作及附件动作。安全完整性等级(SIL)验证属于概率学领域研究范畴,影响失效率的因素多且复杂。如果SIL验证无法通过,将造成大量的设计变更,浪费工程投资,影响工期。设计人员应关注SIL定级报告中关键动作的识别、要求平均失效概率以及SIF回路架构的约束。按照文中方法优化测量元件、逻辑控制器、执行元件及辅助元件的设计,可增加通过验证的概率。在没有预验证及安全要求规格书时,可以参考文中典型可通过SIL验证的SIF回路的经验架构进行优化设计,以减少工程变更。  相似文献   
47.
Wei  Shaowei  Yu  Guoxian  Wang  Jun  Domeniconi  Carlotta  Zhang  Xiangliang 《Machine Learning》2021,110(6):1505-1526
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...  相似文献   
48.
Qin  Yi  Tao  Xianping  Huang  Yu    Jian 《World Wide Web》2019,22(1):1-37
World Wide Web - Rule mechanism has been widely used in many areas, such as databases, artificial intelligent and pervasive computing. In a rule mechanism, rule activation decides which rules are...  相似文献   
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为了研究循环流化床(CFB)锅炉燃用无烟煤时床温及选择性非催化还原(SNCR)脱硝对于NO和N2O排放的影响,在1 MW CFB试验装置上开展了试验研究。结果表明:床温由880 ℃提高到970 ℃,NO排放质量浓度由119.5 mg/m3上升到226.0 mg/m3,N2O排放质量浓度由216.0 mg/m3降低到102.2 mg/m3;在氨氮摩尔比(NSR)为0~3.7之间,随着NSR的提高,脱硝效率从0上升到50.72%;进一步提高NSR到5.2,脱硝效率升至53.61%,增加较为缓慢;随着NSR从0提高到1.7,N2O排放质量浓度由84.3 mg/m3上升至118.3 mg/m3,增长较为缓慢;进一步提高NSR至2.0,N2O排放质量浓度上升至187.7 mg/m3,增长速度提高;继续提高NSR至5.2,N2O排放质量浓度上升至381.4 mg/m3;CFB锅炉采用以尿素为还原剂的SNCR脱硝工艺时,单纯通过加大NSR来提高脱硝效率不仅效果有限,过量喷入的还原剂会造成N2O排放量的显著提高。  相似文献   
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