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Selective hydrodeoxygenation of guaiacol to cyclohexanol using activated hydrochar-supported Ru catalysts

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Frontiers of Chemical Science and Engineering 2024年第5期18卷 13-22页

作者： Kaile Li Shijie Yu Qinghai Li yanguo zhang Hui Zhou Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO2 Utilization and Reduction TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China Department of Chemical and Biomolecular Engineering National University of SingaporeSingapore117585Singapore

Lignin,an abundant aromatic polymer in nature,has received significant attention for its potential in the production of bio-oils and chemicals owing to increased resource availability and environmental issues.The hydrodeoxygenation of guaiacol,a lignin-derived monomer,can produce cyclohexanol,a nylon precursor,in a carbon-negative and environmentally friendly manner.This study explored the porous properties and the effects of activation methods on the Ru-based catalyst supported by environmentally friendly and cost-effective hydrochar.Highly selective cleavage of C_(ary)-O bonds was achieved under mild conditions(160°C,0.2 MPa H2,and 4 h),and alkali activation further improved the catalytic activity.Various characterization methods revealedthat hydrothermal treatment and alkali activation relatively contributed to the excellent performance of the catalysts and influenced their porous structure and Ru dispersion.X-ray photoelectron spectroscopy results revealed an increased formation of metallic ruthenium,indicating the effective regulation of interaction between active sites and supports.This synergistic approach used in this study,involving the valorization of cellulose-derived hydrochar and the selective production of nylon precursors from lignin-derived guaiacol,indicated the comprehensive and sustainable utilization of biomass resources.

关键词： hydrochar guaiacol cyclohexanol activation full-component utilization

Preparation of lactic acid bacteria compound starter cultures based on pasting properties and its improvement of glutinous rice flour and dough

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Food Science and Human Wellness 2024年第4期13卷 2090-2101页

作者： Dengyu Wang Linlin Liu Bing Wang Wenjian Xie yanguo Shi Na zhang Hongchen Fan Key Laboratory of Food Science and Engineering of Heilongjiang Ordinary Higher Colleges Key Laboratory of Grain Food and Comprehensive Processing of Heilongjiang ProvinceCollege of Food EngineeringHarbin University of CommerceHarbin 150076China

The effects of 5 lactic acid bacteria(LAB)fermentation on the pasting properties of glutinous rice flour were compared,and suitable fermentation strains were selected based on the changes of viscosity,setback value,and breakdown value to prepare LAB compound starter cultures.The results revealed that Latilactobacillus sakei HSD004 and Lacticaseibacillus rhamnosus HSD005 had apparent advantages in increasing the viscosity and reducing the setback and breakdown values of glutinous rice flour.In particular,the compound starter created using the two abovementioned LAB in the ratio of 3:1 had better performance than that using a single LAB in improving the pasting properties and increasing the water and oil absorption capacity of glutinous rice flour.Moreover,the gelatinization enthalpy of the fermented samples increased significantly.For frozen glutinous rice dough stored for 28 days,the viscoelasticity of frozen dough prepared by compound starter was better than that of control dough,and the freezable water content was lower than that of control dough.These results indicate that compound LAB fermentation is a promising technology in the glutinous rice-based food processing industry,which has significance for its application.

关键词： Glutinous rice flour Glutinous rice dough Lactic acid bacteria compound starter cultures Pasting properties Viscoelasticity

Breaking the temperature limit of hydrothermal carbonization of lignocellulosic biomass by decoupling temperature and pressure

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Green Energy & Environment 2023年第4期8卷 1216-1227页

作者： Shijie Yu Xiaoxiao Yang Qinghai Li yanguo zhang Hui Zhou Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Beijing Key Laboratory of CO_(2) Utilization and Reduction TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing100084China

Hydrothermal carbonization(HTC) of lignocellulosic biomass is a promising technology for the production of carbon materials with negative carbon emissions. However, the high reaction temperature and energy consumption have limited the development of HTC technology. In conventional batch reactors, the temperature and pressure are typically coupled at saturated states. In this study, a decoupled temperature and pressure hydrothermal(DTPH) reaction system was developed to decrease the temperature of the HTC reaction of lignocellulosic biomass(rice straw and poplar leaves). The properties of hydrochars were analyzed by scanning electron microscopy(SEM), Fourier transform infrared(FTIR) spectroscopy, X-ray photoelectron spectroscopy(XPS), Raman spectroscopy, X-ray diffraction(XRD), thermogravimetric analyzer(TGA), etc. to propose the reaction mechanism. The results showed that the HTC reaction of lignocellulosic biomass could be realized at a low temperature of 200℃ in the DTPH process, breaking the temperature limit(230℃) in the conventional process. The DTPH method could break the barrier of the crystalline structure of cellulose in the lignocellulosic biomass with high cellulose content, realizing the carbonization of cellulose and hemicellulose with the dehydration, unsaturated bond formation, and aromatization. The produced hydrochar had an appearance of carbon microspheres, with high calorific values, abundant oxygen-containing functional groups, a certain degree of graphitization, and good thermal stability. Cellulose acts not only as a barrier to protect itself and hemicellulose from decomposition, but also as a key precursor for the formation of carbon microspheres. This study shows a promising method for synthesizing carbon materials from lignocellulosic biomass with a carbon-negative effect.

关键词： Biomass Lignocellulose Hydrothermal treatment Hydrochar Carbon materials

Effect of bed size on the gas-solid flow characterized by pressure fluctuations in bubbling fluidized beds

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Particuology 2019年第6期17卷 1-9页

作者： Jie Xiang yanguo zhang Qinghai Li Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University-University of Waterloo Joint Research Center for Micro/Nano Energy&1 Environment TechnologyDepartment of Energy and Power EngineeringTsinghua UniversityBeijing 100084China

Pressure fluctuations in four bubbling fluidized beds having different bed sizes (three square cross-sections of 5, 10, and 15 cm in side length, and one rectangular cross-section of 2 × 10 cm2) were measured at four axial positions (P1, P2, P3, and P4). Several characteristic indicators of the flow specifically of the pressure were calculated. In terms of these characteristic indicators, the effect of bed size on flow behavior was investigated. The results show that in the fully fluidized state, the pressure drop is slightly higher in smaller beds, but the pressure drops in the 10- and 15-cm beds are close. The 15-cm bed has the lowest pressure-fluctuation amplitude. The amplitudes at P1 and P2 in the lower part of the bed are very close for bed sizes below 10 cm, but the amplitude at P3 near the bed surface increases with decreasing bed size. No general trend was observed regarding the effect of bed size on skewness and kurtosis of the pressure for all four axial heights. For the average, standard deviation, skewness, and kurtosis of the pressure at P4, the values are close for the two small beds (2 × 10 and 5 × 5 cm2) and the two large beds (10 × 10 and 15 × 15 cm2), and hence the effect of bed size separates the beds into two groups. In the fully fluidized state, for P1, P2, and P3, the Kolmogorov entropy and the dominant frequency both increase with increasing bed size, but in the pseudo-2D bed both are between the values for the 5- and 10-cm beds.

关键词： Bubbling fluidized bed Pressure fluctuation Bed size Time-series analysis Dominant frequency Kolmogorov entropy

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氯化铷添加剂对钙钛矿太阳能电池性能的影响

清华大学学报（自然科学版） 2024年第5期64卷 879-888页

作者：高宇张衍国周会李清海清华大学能源与动力工程系热科学与动力工程教育部重点实验室北京100084

在钙钛矿前驱体溶液中加入添加剂,是改善钙钛矿薄膜质量、提高钙钛矿太阳能电池性能的重要手段。该研究采用氯化铷(RbCl)作为添加剂,通过扫描电子显微图像、 X射线衍射图谱、光致发光光谱等表征手段,研究了不同比例添加RbCl对钙钛矿薄... 详细信息

在钙钛矿前驱体溶液中加入添加剂,是改善钙钛矿薄膜质量、提高钙钛矿太阳能电池性能的重要手段。该研究采用氯化铷(RbCl)作为添加剂,通过扫描电子显微图像、 X射线衍射图谱、光致发光光谱等表征手段,研究了不同比例添加RbCl对钙钛矿薄膜形貌与结构的影响,并通过外量子效率测试等方法,比较了不同比例RbCl添加后的钙钛矿太阳能电池器件性能。结果表明:RbCl的添加有利于引导钙钛矿晶粒生长,增大晶粒尺度,形成致密薄膜,从而抑制界面处载流子复合。适量添加RbCl后,钙钛矿太阳能电池的光电转化效率从18.88%提升到20.06%,开路电压、短路电流密度和填充因子等参数均显著提高,钙钛矿太阳能电池性能得到明显改善。

关键词：钙钛矿太阳能电池氯化铷添加剂钙钛矿薄膜晶粒尺寸

基于改进混合量子遗传算法的二相编码雷达波形优化

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通信学报 2024年第1期45卷 129-140页

作者：张余赵婧贾彦国沈秀敏燕山大学信息科学与工程学院河北秦皇岛066004 燕山大学经济管理学院河北秦皇岛066004 河北省计算机虚拟技术与系统集成重点实验室河北秦皇岛066004 河北省软件工程重点实验室河北秦皇岛066004

针对当前雷达波形优化算法搜索策略单一、适用范围受限的问题,提出了一种基于改进混合量子遗传算法的二相编码雷达波形优化算法。所提算法采用了一种新的自适应旋转角度策略,根据迭代次数和余弦相似度动态调整旋转角度,提高了算法的收... 详细信息

针对当前雷达波形优化算法搜索策略单一、适用范围受限的问题,提出了一种基于改进混合量子遗传算法的二相编码雷达波形优化算法。所提算法采用了一种新的自适应旋转角度策略,根据迭代次数和余弦相似度动态调整旋转角度,提高了算法的收敛速度、全局搜索能力和求解质量。仿真结果表明,与遗传算法、基本量子遗传算法和混合量子遗传算法相比,对于包含了单峰、多峰和非凸优化问题的6个标准测试函数,所提算法在质量和资源消耗上均表现更好;对于二相编码雷达波形优化,证实了使用所提算法优化波形是可行和有效的。

关键词：相位编码雷达波形量子遗传算法自适应旋转角度策略峰值旁瓣电平

Study on drying and combustion process in grate-CFB incinerator

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Science China(Technological Sciences) 2009年第5期52卷 1153-1160页

作者： QingHai Li yanguo zhang MeiQian Chen AiHong Meng ChangHe Chen Key Laboratory for Thermal Science and Power Engineering of Ministry of Education Tsinghua University Beijing 100084 China School of Mechanical Electronical and Control Engineering Beijing Jiaotong University Beijing 100044 China

The drying and combustion process in the combined grate and circulating fluidized bed(grate-CFB) municipal solid waste(MSW) incinerator was investigated experimentally and mathematically.The drying grate bed was simulated by a muffle furnace,which could be controlled at a constant tempera-ture level.The kind of wastes,thickness of waste layer fed and temperature were chosen as the ad-justable parameters to study their effect on the drying process.The experimental results indicated that the hydrophilic wastes were more difficult to be dried than the hydrophobic wastes.The higher the temperature is the easier the waste is to be dried.The thinner waste layer is favorable to drying the waste.The pyrolysis experiment in the furnace showed that the higher temperature level could reduce the conversion rate of carbon to carbon monoxide.The semi-empirical mathematical model that in-cluded the bed material distribution submodel,volatile matter release submodel,carbon particle combustion submodel and so on was proposed.A 260 t/d grate-CFB incinerator was modeled and the model predicted bulk density agreed with the measured value from industrial field test.The predicted flue gas(e.g.CO2,CO) concentration deviated slightly from the industrial test data.The parameters and variables used in the model were determined by the experiments or practical field test.This model can be used to design the grate-CFB incinerator and guide its operation.

关键词： drying waste incineration grate-CFB combustion model

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钼含量对高铬铸铁堆焊层组织及耐磨性的影响

钢铁 2024年第4期59卷 148-158,178页

作者：张凯郭智孙东云李艳国张明燕山大学亚稳材料制备技术与科学国家重点实验室河北秦皇岛066004 秦皇岛港股份有限公司第七港务分公司河北秦皇岛066003 华北理工大学冶金与能源学院河北唐山063210

高铬铸铁堆焊层因其较高的耐磨性而广泛应用于各种大型工业设备的内部衬板,研究发现Mo系碳化物可为初生碳化物的生成提供形核点从而细化组织,但Mo元素除了提供形核点外是否对组织存在别的作用仍尚待研究。为了研究Mo含量对高铬铸铁堆焊... 详细信息

高铬铸铁堆焊层因其较高的耐磨性而广泛应用于各种大型工业设备的内部衬板,研究发现Mo系碳化物可为初生碳化物的生成提供形核点从而细化组织,但Mo元素除了提供形核点外是否对组织存在别的作用仍尚待研究。为了研究Mo含量对高铬铸铁堆焊层组织与性能的影响,设计了一种含Mo超高碳高铬堆焊耐磨板,利用XRD、SEM分析了Mo元素对堆焊层组织、相组成以及磨损后堆焊层表面和纵截面的影响,利用EDS分析了元素在各相中的分配情况,并进一步利用硬度和干砂磨料磨损试验,研究了Mo合金化对高铬高碳堆焊层硬度和耐磨性的影响。结果表明,Fe-Cr-Mo-C合金堆焊层组织主要由γ相、M_(7)C_(3)(M=Fe、Cr)组成。随着Mo含量的提高,堆焊层内初生碳化物含量降低,奥氏体含量增加,单个初生碳化物尺寸先减小后增大;初生碳化物硬度增加,堆焊层宏观硬度先增加后降低;磨损后初生碳化物截断裂纹减少,剥落逐渐减少,其中30Mo试样出现了共晶碳化物的剥落。加入0.13%Mo后磨损失重减少了13.6%,加入0.30%Mo后磨损失重增加了20.0%。这是因为Mo原子的加入会提高初生碳化物的硬度,但是初生碳化物含量在减少,从而导致了堆焊层硬度先升高后降低,磨损失重量先减小后增大。研究结果对高铬铸铁堆焊层制备过程中选择适宜的Mo添加量提供了指导。试验设计了Mo质量分数为0.04%~0.30%的3个试样,结果表明,初生碳化物出现了先细化后粗化的趋势,对这部分变化的趋势还有待进一步细化研究。

关键词： Fe-Cr-C合金堆焊 Mo合金化耐磨性 M7C3碳化物

走人与自然和谐共生的现代化之路——在“中国式现代化道路与中华民族伟大复兴”学术研讨会上的主旨报告

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南昌师范学院学报 2024年第2期45卷 19-22页

作者：张艳国华中师范大学

中国式现代化道路关系到中华民族伟大复兴的历史伟业，从中国式现代化道路丰富的科学内涵和显著的时代特征来看，走人与自然和谐共生的现代化之路是现实选择和科学路径。探讨走人与自然和谐共生的现代化之路，要有明确的问题意识，既要... 详细信息

中国式现代化道路关系到中华民族伟大复兴的历史伟业，从中国式现代化道路丰富的科学内涵和显著的时代特征来看，走人与自然和谐共生的现代化之路是现实选择和科学路径。探讨走人与自然和谐共生的现代化之路，要有明确的问题意识，既要关注学术界有关中国式现代化命题的热烈探讨，也要回应广大民众对美好生活向往的普遍关切，更要依据党和国家的重大方针政策与决定，如此才能做到合理阐释、科学分析、精准解答相关理论和现实问题，从而为中国式现代化道路和中华民族伟大复兴贡献更多智慧和更大力量。

关键词：人与自然和谐共生中国式现代化