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An L.,Tianjin University of Science and Technology | Wang G.,Tianjin University of Science and Technology | Wang G.,South China University of Technology | Wang G.,University of Science and Technology of China | And 5 more authors.
International Journal of Biological Macromolecules | Year: 2017

The heterogeneity of lignin chemical structure and molecular weight results in the lignin inhomogeneous properties which also covers the antioxidant performance. In order to evaluate the effects of lignin heterogeneity on its antioxidant activity, four lignin fractions from enzymatic hydrolysis lignin were classified by sequential organic solvent extraction and further evaluated by DPPH (1,1-Diphenyl-2-Picrylhydrazyl) free radical scavenging capacity and reducing power analysis. The characterization including FTIR, 1H NMR and GPC showed that the fractionation process could effectively separate lignin fractions with distinctly different molecular weight and weaken the heterogeneity of unfractionated lignin. The antioxidant performance comparison of lignin fractions indicated that the dichloromethane fraction (F1) with lowest molecular weight (4585 g/mol) and highest total phenolics content (246.13 mg GAE/g) exhibited the highest antioxidant activity whose value was close to commercial antioxidant BHT (butylated hydroxytoluene). Moreover, the relationship between the antioxidant activity and the structure of lignin was further discussed to elucidate the mechanism of antioxidant activity improvement of lignin fractionation. Consequently, this study suggested that the sequential extraction was an effective way to obtain relatively homogeneous enzymatic hydrolysis lignin fractions which showed the potential for the value-added antioxidant application. © 2017 Elsevier B.V.


Qu Y.,Shandong University of Finance and Economics | Jiang G.,Beijing Normal University | Shang R.,Shandong Agriculture and Engineering College | Gao Y.,Shandong University of Finance and Economics
Nongye Gongcheng Xuebao/Transactions of the Chinese Society of Agricultural Engineering | Year: 2014

As seen through history, the construction and development of rural residential land is spontaneous, and unified scientific planning is lacking in China. In the interaction of many factors, the inflation scale of the natural rural residential land is very rapidly, and land use patterns in the rural areas are spontaneous, disorder, hollow, idle, more houses and so on. The results show that much land resources are wasted and the spatial pattern of land is seriously defaced. Consequently, the intensive use of rural residential land is the key to the construction of urban and rural integration patterns, and also is the main way to promote resource conservation and utilization. With further deepening of the regional economic and social reforms and changes of farmers' demands, it was foreknown that rural residents' land would produce further differentiation and and require reconstruction. If appropriate intervention and effective guidance is not provided, the risk of extensive use of rural residential land would be strengthened, and intensive utilization of rural residential land would become an urgent research subject. First, according to the economics input-output theory and new rural construction requirements, this study classified the connotation and manifestation of elements of rural residential land use as two aspects, intensity and efficiency, to construct the index system of rural residential land use intensity measurement using the scale, layout, structure and production, life, and ecology efficiency as the criterion layer. Second, with the help of the decoupling principle and index deviation degree analysis method, the study established the intensity degree index model and its correction model, based on the coefficient of variation and obstruction diagnosis model, for rural residential land intensive use. The study then took the Pinggu district in Beijing, with significant suburban characteristics, as an example, and took 275 administrative villages as the basic assessment unit to assess the intensity level, divided these into different intensity modes, analyzed the intensity disturbance factors, and summed up the intensity control path. The results showed that: 1) On the whole, rural residential land use intensity level is low, the ecological and loss modes of rural residential land occupied the dominant position, the amount of excess type in intensive and extensive modes was not much, but there were significant differences between each village and town. 2) Obstacle factors of rural residential land intensive use were significant, relatively large scale and unreasonable internal structures were the main obstacles to cause higher strength of rural residential land use, and low production efficiency and poor living conditions were the factors to restrict the development of rural settlements. 3) From ecological mode to intensive mode to extensive mode to loss mode, the obstacle factors were increasing gradually. From the point of reducing the intensity of land use and enhancing the efficacy of land use, tapping potential, intensive growth, ecological balance, and sustainable development were the effective paths for different types of rural residential land. Following the complexity and particularity of rural residential land, with the element input-output theory and the decoupling theory, the study took the intensity index and efficiency index as the basis to assess the intensity level and divided the intensity mode of rural residential land. It was more comprehensive than a single index system, such as the area and population index, to reflect the rural land use characteristics. The study made theoretical connotation innovations in the aspect of rural residential land intensive use measurement, and the results were very useful in accelerating the rational use of land resources in rural areas and promoting the coordinated development of social economy and ecological environments in rural areas.


Sui R.,Shandong University | Sui R.,Engineering and Technology Research Center for Special Equipment Safety of Shandong Province | Sui R.,Shandong Agriculture and Engineering College | Wang W.,Shandong University | And 5 more authors.
Engineering Failure Analysis | Year: 2014

Leakage at the tube-to-tubesheet joints occurred in a waste heat boiler. The mode and the root cause of the failure were investigated by chemical composition analysis of the tube material, metallographic structure and crack observation, and corrosion product analysis of the damaged tubes, as well as the operation condition examination of the waste heat boiler. Results revealed that failure of the tubes occurred due to the stress corrosion cracking (SCC), which was caused by tensile stress and chloride-buildup in the narrow and long gap between the tube and tubesheet hole. The gap formation was further analyzed by comparison of the minimum expansion pressure from the common formula provided by the manufacturer, with that from finite element method computations. It is found that the minimum expansion pressure used in manufacture is small and cannot eliminate the initial gap. Meanwhile, the enrichment of chloride in the gap was briefly discussed. © 2014 Elsevier Ltd.


Peng L.,Shandong Agriculture and Engineering College
Advanced Composites Letters | Year: 2013

This work is based on the dry sliding wear of Stellite 4-FeSi-B4C composites deposited on a TA10 titanium alloy using a Laser melting deposition (LMD) technique, the parameters of which are such as to provide almost crack-free composites with very low porosity. To our knowledge, it is the first time that Stellite4-FeSi-B4C mixed powders are deposited as the hard composites by the LMD technique. Scanning electron microscope results indicate the nanoscale particles and nanorods are produced in such composites. Furthermore, due to the characteristics of the laser technology, the ultrafine nanoscale polycrystalline phases can be easily produced. Compared with a TA10 alloy substrate, the improvements of the micro-hardness and wear resistance are obtained for such composites.


Sui R.J.,Shandong Agriculture and Engineering College | Chen S.Y.,Shandong University | Zhou C.,Dalian Boiler & Pressure Vessel Inspection & Research Institute | Liu H.B.,Dalian Boiler & Pressure Vessel Inspection & Research Institute | Chu Y.H.,Dalian Boiler & Pressure Vessel Inspection & Research Institute
Advanced Materials Research | Year: 2014

Temperature and operating pressure are important to stress corrosion cracking (SCC) of stainless steel. The SCC susceptibility of 18-8 type austenitic stainless steel, 06Cr18Ni11Ti (S32168), in an environment containing hydrogen chloride was assessed using the slow strain rate tensile (SSRT) test under different temperature and operating pressure. Results of the SSRT test indicated that the impact of operating pressure on the SCC susceptibility was different at different temperatures. The correlation degrees of temperature and operating pressure to SCC susceptibility were calculated using the grey relational theory. The correlation degree of temperature to the SCC susceptibility was greater than that of operating pressure to the SCC susceptibility. © (2014) Trans Tech Publications, Switzerland.


Zhao S.,University of Science and Technology of China | Qingmin C.,Shandong Agriculture and Engineering College | Fu M.,University of Science and Technology of China | Yang X.,University of Science and Technology of China | And 2 more authors.
Quality Assurance and Safety of Crops and Foods | Year: 2015

The effects of exogenous ethylene generated by solid ethylene-releasing agents on carbohydrate metabolism and sprouting in potato tubers at 15 °C were investigated in this study. Potato tubers were randomly divided into 4 groups, and treated with 0, 1, 2, and 3 bags of solid ethylene-releasing agents. The initial time of potato tuber sprouting and sprouting index were recorded. The rate of respiration, total sugar, total reducing sugar, starch, fructose, glucose, and sucrose content during the sprouting were determined. Our result indicated that exogenous ethylene inhibited the sprouting of potato tubers (sprout index from 0.583 to 1.125), whereas little effect on the initial time of sprouting was observed. Moreover, exogenous ethylene enhanced respiration slightly (less than 8.2%), elevated the total sugar (from 17.73 to 32.58 mg/g) and reduced sugar levels (from 0.23 to 4.43 mg/g). Nevertheless, the starch, glucose, and fructose content varied minimally. The sucrose content was decreased significantly by exogenous ethylene. Therefore, exogenous ethylene treatment could inhibit the potato sprouting process, and a dose-dependent relationship was observed between exogenous ethylene and sprouting index. The inhibitory effect of sprouting was related to carbohydrate metabolism, including changes in the total sugar, total reducing sugar, and sucrose content, to some extent. © 2014 Wageningen Academic Publishers.


Chen Q.,Shandong Agriculture and Engineering College | Fu M.,University of Science and Technology of China | Qu Q.,University of Science and Technology of China | Dai H.,Shandong Agriculture and Engineering College | Zhao S.,University of Science and Technology of China
Quality Assurance and Safety of Crops and Foods | Year: 2015

Effect of two blanching methods (blanching in steam or in hot water), on antioxidant properties of daylily flowers were determined with antioxidant assays, including 1-diphenyl-2-picrylhydrazyl free radical scavenging, superoxide anion scavenging activity, reducing power and nitric oxide radical-scavenging. Antioxidant compounds, such as phenolic composition, ascorbic acid and ß-carotene were also analysed. Results showed that the phenolic compounds, ß-carotene, ascorbic acid and antioxidant activities in daylily flowers were affected significantly by blanching pre-treatments. Blanching enhanced antioxidant activities and (+)-catechin content, and resulted in great reduction of ß-carotene, ascorbic acid, but steam blanching had the higher antioxidant activity and related compound contents than those of hot water blanching. A significant positive correlation between antioxidant activity and (+)-catechin content was observed in this work. Overall, steam blanching would be a better choice for daylily flower pre-treatment than blanching in hot water. © 2014 Wageningen Academic Publishers.

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