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不同水解方式下陈皮键合态挥发性化合物的比较

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食品与发酵工业 2024年第14期50卷 50-59页

作者：李笛帆李玉婷余祥英杨金易华南农业大学食品学院广东广州510642 东莞理工学院生命健康与技术学院中国轻工业健康食品开发与营养调控重点实验室东莞市特色食品精准设计重点实验室食品营养健康工程与智能化加工研究中心广东东莞523808

为比较不同水解条件对陈皮键合态挥发性化合物释放的影响,采用Amberlite XAD-2树脂吸附洗脱分离得到陈皮中键合态挥发性化合物前体,将其在β-葡萄糖苷酶、果胶酶、混合酶(β-葡萄糖苷酶与果胶酶)和酸4种条件下进行水解释放,采用GC-MS和... 详细信息

为比较不同水解条件对陈皮键合态挥发性化合物释放的影响,采用Amberlite XAD-2树脂吸附洗脱分离得到陈皮中键合态挥发性化合物前体,将其在β-葡萄糖苷酶、果胶酶、混合酶(β-葡萄糖苷酶与果胶酶)和酸4种条件下进行水解释放,采用GC-MS和气相色谱-离子迁移谱(gas chromatography-ion mobility spectrometry,GC-IMS)对水解得到的键合态挥发性化合物进行分离分析。GC-MS分析显示,3种酶法水解得到的键合态挥发性化合物共有35种,其中β-葡萄糖苷酶和混合酶水解得到的化合物主要为酯类(占比分别高达93.42%和90.55%),以苯甲酸甲酯含量最高,辛酸甲酯等脂肪酸甲酯次之,这些成分在游离态挥发性成分以及果胶酶水解中未检出;酸法水解得到的键合态挥发性化合物共有50种,主要为萜烯结构的醛类、醇类。GC-IMS分析显示,酶解生成的成分以醛、醇类为主,果胶酶酶解释放的化合物组成与空白组类似,酸解生成的成分以醛、酮、酸类为主。综上所述,β-葡萄糖苷酶较果胶酶更利于陈皮键合态挥发性化合物的释放,且水解条件较酸解温和,是释放陈皮键合态挥发性化合物的较优选择。

关键词：陈皮挥发性化合物键合态酶水解酸水解 β-葡萄糖苷酶

Vicinal hydroxyl group-inspired selective oxidation of glycerol to glyceric acid on hydroxyapatite supported Pd catalyst

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Green Energy & Environment 2022年第4期7卷 691-703页

作者： difan li Xiuge Zhao Qingqing Zhou Bingjie Ding Anna Zheng Qingpo Peng Zhenshan Hou Key Laboratory for Advanced Materials Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai200237China

Selective oxidation of glycerol provides a feasible route towards the sustainable synthesis of high value-added ***,the hydroxyapatite(HAP)supported palladium(Pd)species were fabricated by impregnation and subsequent *** as-obtained heterogeneous Pd catalyst afforded not only excellent selectivity to glyceric acid(GLA)up to 90%with 59%conversion of glycerol but also good recyclability by using molecular oxygen as an oxidant under mild *** characterization of catalysts indicated that both the surface basicity and Pd sites on the catalyst played a crucial role in promoting glycerol ***,it demonstrated that the presence of the vicinal hydroxyl group of glycerol molecule can assist the oxidation reaction via forming a coordination between the vicinal hydroxyl group and Ca^(2+) sites on HAP-derived *** this catalytic process,the secondary hydroxyl of glycerol kept untouched and the primary hydroxyl of glycerol was converted into carboxyl group,while the Pd species acted as active centers for cooperatively promoting the subsequent oxidation to generate ***,this catalytic system can be extended widely for the oxidative conversion of other vicinal diols into the corresponding a-hydroxycarboxylic acids *** labeling experiment using H_(2)^(18)O confirmed that H_(2)O not only acted as solvent but also was involved in the catalytic *** the basis of the results,a possible reaction mechanism has been *** HAP-supported Pd catalytic system has been shown to serve as an effective approach for the upgrading of bio-derived vicinal diols to high value-added chemicals.

关键词： Hydroxyapatite Palladium Glycerol oxidation Glyceric acid Vicinal hydroxyl group

工程塑料环境因素与载荷应力耦合作用试验装置研究

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装备环境工程 2024年第2期21卷 137-144页

作者：刘群陈星昊钟勇杨万均杨昊雨李迪凡西南技术工程研究所重庆400050

目的设计一种能够模拟工程塑料实际服役工作环境的试验装置,在多型自然环境中,构建兼具环境因素侵蚀与载荷应力耦合作用的试验条件。方法研制工程塑料环境因素与载荷应力协同作用试验装置,采用包括拉伸加载、弯曲加载、控制系统等组... 详细信息

目的设计一种能够模拟工程塑料实际服役工作环境的试验装置,在多型自然环境中,构建兼具环境因素侵蚀与载荷应力耦合作用的试验条件。方法研制工程塑料环境因素与载荷应力协同作用试验装置,采用包括拉伸加载、弯曲加载、控制系统等组件的模块化设计,实现0.01~16 Hz加载频率的拉伸及弯曲载荷,最大1 550 kg的拉伸载荷,最大375 kg的弯曲载荷。结果将研制完成的试验装置置于多型自然环境下对试验施加恒定和交变载荷,以真实模拟工程塑料实际服役中的环境因素与载荷应力协同作用。结论试验装置制造加工难度小,结构稳定可靠,可用于评价和研究工程塑料等系列类型材料的环境损伤性能演变。

关键词：工程塑料环境应力协同作用自然环境试验试验装置交变载荷装置设计

Conversion of biomass to chemicals over zirconium phosphate-based catalysts

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Chinese Journal of Catalysis 2017年第11期38卷 1784-1793页

作者： difan li Wenxiu Ni Zhenshan Hou School of Chemistry and Molecular Engineering East China University of Science and TechnologyShanghai 200237 China Research Institute of Industrial Catalysis Shanghai 200237 China Key Laboratory for Advanced Materials Shanghai 200237 China

*** is an important phenomenon in nature and is involvedin all areas of the chemical *** andheterogeneous catalysis are key techniques in chemical *** development of efficient,stable,and environmentallyfriendly catalytic methods is receiving much attentionbecause of the increasing global shortage of energy and seriousenvironmental damage.A number of efforts have been made inthe past for designing rationally catalysts to achieve desirablecatalytic activities,selectivities,and stabilities for specific reactions[1].The current energy crisis is affecting economies inevery region,particularly in fossil‐oil‐consuming countries,because of rapidly decreasing available stocks,therefore biomassconversion to fuels and chemicals using various approaches,including thermal,biological,and chemocatalyticprocesses,is attracting great attention worldwide[2].

关键词：磷酸锆固体酸生物质转化脱水加氢

THE CHALLENGES FOR THE ENFORCEMENT AGAINST COPYRIGHT VIOLATIONS IN CHINA UNDER THE TRIPS AGREEMENT

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Frontiers of Law in China-Selected Publications from Chinese Universities 2012年第2期7卷 244-268页

作者： difan Qu Yahong li 1. Faculty of Law The University of Hong Kong Pokfulam Hong Kong China 2. Faculty of Law The University of Hong Kong Pokfulam Hong Kong China

While piracy is a serious problem in China, it is also a global concern. Within the domestic and the TRIPS context, this article discusses various forms of copyright violations in China, their impact on the enforcemen... 详细信息

关键词： intellectual property Intellectual Property Rights World Trade Organization problems existing

Microstructure Evolution and Grain Coarsening Behaviour During Partial Remelting of Cyclic Extrusion Compression Formed AZ61 Magnesium Alloy

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Acta Metallurgica Sinica(English Letters) 2013年第2期26卷 149-156页

作者： Changpeng WANG Huasheng MEI Rongqiang li difan li ling WANG Jie liU Zehui HUA lijin ZHAO Feifei PEN Hui li No.59 Institute of China Ordnance Industry

The effects of CEC passes, isothermal holding time and reheating temperature on the microstructure evolution and grain coarsening behaviour of AZ61 magnesium alloy produced by the recrystallisation and partialmelting （RAP） process were investigated. Before partial remelting, as-cast AZ61 alloy was deformed by cyclic extrusion compression （CEC） with one pass and two pass at 330 ℃. After CEC, the microstructure consisted of unrecrystallized grains and deformed eutectic compounds. Increasing isothermal holding time resulted in the formation of spheroidal grains surrounded by liquid films. With increasing the isothermal holding time, the solid grain size increased and the degree of spheroidization was improved. With increasing the reheating temperature, namely increasing liquid fraction, the solid grain size obviously decreased during the period from 560 ℃ to 570 ℃ and then slightly increased after 570 ℃, while the shape factor increased monotonously. During partial remelting, increasing reheating temperature can properly short the isothermal holding time to obtain fine structure. Moreover, increasing the numbers of CEC passes could produce finer semi-solid microstructure. The coarsening behavior of solid grains in the semi-solid state obeys Ostwald ripening and grain coalescence mechanisms. The coarsening rate constant, K, 595 ℃. After CEC plus partial remelting, the ideal and fine was suitable for thixoforming. was 80μm^3.s^-1 for samples partially remelted at semi-solid state structure can be obtained, which

关键词： AZ61 magnesium alloy Cyclic extrusion compression Microstructureevolution Grain coarsening

Selective Oxidation of Glycerol with Hydrogen Peroxide Using Silica- Encapsulated Heteropolyacid Catalyst

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物理化学学报 2018年第8期34卷 886-895页

作者： YUAN Mingming li difan ZHAO Xiuge MA Wenbao KONG Kang NI Wenxiu GU Qingwen HOU Zhenshan Key Laboratory for Advanced Materials Research Institute of Industrial Catalysis School of Chemistry & Molecular Engineering East China University of Science and Technology Shanghai 200237 P. R. China.

The Keggin type heteropolyacids (HPAs) have attracted increasing attention due to their strong Bronsted acidity and excellent redox properties, which could play an important role in accelerating the conversion of bio-derived molecules. In this work, heteropolyacid (HPA, H_4PMo_(11)VO_(40)) encapsulated by silica was synthesized by a sol-gel method and a sequential silylation technique (HPA@SiO_2-N_2-S). The as-synthesized material was characterized by Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscope (SEM) and transmission electron microscopy (TEM). The FT-IR spectra show that the HPA anions preserved their Keggin structure when incorporated into the catalyst. The XRD patterns show that HPA molecules are uniformly dispersed within the silica network. The SEM and TEM images confirm that the catalyst was composed of spherical nanometer-sized particles. The porous properties of the catalysts measured by the N_2 adsorption-desorption isotherms indicate that the Brunauer, Emmett and Teller (BET) surface area of pure SiO_2 was 287 m~2·g~(–1), but upon encapsulation of HPA into the silica matrix, a lower surface area (245 m~2·g~(–1)) was measured for the resulting material. In addition, the pore diameter was reduced after silylation. Furthermore, the hydrophobicity of the catalysts was investigated by the measurement of contact angle (CA) with water. The SiO_2 and SiO_2/HPA catalysts were completely hydrophilic and the contact angle was close to 0°. However, the contact angle of the silylated catalyst was determined to be 137°, indicating that the silylation procedure significantly increased the hydrophobicity of the catalyst. The as-prepared catalysts were also used as heterogeneous catalysts for the selective oxidation of glycerol. The prepared material exhibited excellent catalytic activity towards glycerol oxidation, in which the glycerol can be selectively transformed into formic ac

关键词：杂多酸化学分析二氧化硅合成方法

Aluminum(Ⅲ) triflate-catalyzed selective oxidation of glycerol to formic acid with hydrogen peroxide

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Chinese Journal of Catalysis 2019年第4期40卷 534-542,M0003页

作者： Kang Kong difan li Wenbao Ma Qingqing Zhou Guoping Tang Zhenshan Hou Key Laboratory for Advanced Materials Research Institute of Industrial CatalysisSchool of Chemistry and Molecular EngineeringEast China University of Science and TechnologyShanghai 200237China

Glycerol is a by-product of biodiesel production and is an important readily available platform *** of glycerol into value-added chemicals has gained immense ***,we carried out the conversion of glycerol to formic acid and glycolic acid using H2O2 as an oxidant and metal(Ⅲ)triflate-based catalytic ***(Ⅲ)triflate was found to be the most efficient catalyst for the selective oxidation of glycerol to formic acid.A correlation between the catalytic activity of the metal cations and their hydrolysis constants(Kh)and water exchange rate constants was *** 70 ℃,a formic acid yield of up to 72% could be attained within 12 *** catalyst could be recycled at least five times with a high conversion rate,and hence can also be used for the selective oxidation of other biomass platform *** kinetics and 1H NMR studies showed that the oxidation of glycerol(to formic acid)involved glycerol hydrolysis pathways with glyceric acid and glycolic acid as the main intermediate *** the [Al(OH)x]^n+ Lewis acid species and CF3SO3H Brosted acid,which were generated by the in-situ hydrolysis of Al(OTf)3,were responsible for glycerol *** easy availability,high efficiency,and good recyclability of Al(OTf)3 render it suitable for the selective oxidation of glycerol to high value-added products.

关键词： Aluminum(Ⅲ)triflate Glycerol Hydrogen peroxide Selective oxidation Formic acid

温度对7A04铝销-50CrMo4钢盘摩擦副干滑动摩擦磨损行为的影响

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摩擦学学报 2023年第10期43卷 1189-1200页

作者：余梓枫李迪凡邵泳林屈盛官罗丹李小强华南理工大学国家金属材料近净成形工程技术研究中心广东广州510640 中国兵器工业第五九研究所重庆400039

针对7xxx铝合金温热成型过程中模具磨损等问题,本文作者研究了不同温度对7A04铝销-50CrMo4钢盘摩擦副干滑动摩擦磨损行为的影响.采用光学显微镜、3D光学轮廓仪和扫描电子显微镜等对试样的微观组织、磨痕形貌、磨损亚表层组织以及磨屑形... 详细信息

针对7xxx铝合金温热成型过程中模具磨损等问题,本文作者研究了不同温度对7A04铝销-50CrMo4钢盘摩擦副干滑动摩擦磨损行为的影响.采用光学显微镜、3D光学轮廓仪和扫描电子显微镜等对试样的微观组织、磨痕形貌、磨损亚表层组织以及磨屑形貌进行了表征.结果表明,随着试验温度的升高,摩擦系数先降低后升高.7A04铝销的磨损率先减小后增大;其磨损机制以磨粒磨损为主.50CrMo4钢盘的磨损率先增大后减小,在225℃时降至最低;其室温下的磨损机制为磨粒磨损、胶合黏着磨损和剥层磨损的混合磨损机制,温度从125℃升至175℃时转变为轻微磨粒磨损和一般黏着磨损的混合磨损机制;各温度下均存在明显的材料转移现象.7A04铝销在125℃时开始出现机械混合层,伴随有明显的氧化现象,这将导致在225℃下机械混合层结构变得疏松且易剥落.在225℃下50CrMo4钢磨损亚表面的变形晶粒区和动态再结晶区厚度增大,表面硬度下降,塑性增加,形成长条状的切屑.7A04铝销表面机械混合层的氧化及塑性变形层的变化与50CrMo4钢磨损表面动态再结晶的变化决定了在不同温度中2种材料各具有不同的磨损率与磨损形式.

关键词： 7A04铝 50CrMo4钢温度干滑动磨损磨屑