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Improved “cure on demand” of aromatic bismaleimide with thiol triggered by retro-Diels-Alder reaction

Vincent Froidevaux, Mélanie Decostanzi, Abdelatif Manseri, Sylvain Caillol, Bernard Boutevin, Rémi Auvergne

《化学科学与工程前沿（英文）》 2021年第15卷第2期页码 330-339 doi: 10.1007/s11705-020-1929-6

摘要： This study focuses on the synthesis of new liquid aromatic bismaleimide monomers in order to improve self-curing on demand (SCOD) systems previously based on aliphatic bismaleimides. These SCOD systems are based on Diels-Alder (DA)/retro-DA reactions. The syntheses of new different aromatic bismaleimides with ester and amide bonds are presented. These maleimides have been protected using DA reaction and characterized by H NMR analysis to determine protection rate and diastereomer ratios. The retro-DA reactions of both aromatic and aliphatic DA adducts in presence of thiol molecules were studied. Kinetic analysis was monitored by H NMR and compared to model study. Finally, both aromatic and aliphatic bismaleimides-based polymers were synthesized with 2-mercaptoethyl ether and thermal properties of polymers were compared. The glass transition temperature values ranged from –20 °C to 14 °C and very good thermal stabilities were observed (up to 300 °C).

关键词： thiol-ene polymerization self-curing on demand thia-michael addition Diels-Alder maleimide

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Sinks of steel in China–addition to in-use stock, export and loss

Hua GUO,Tianzhu ZHANG

《环境科学与工程前沿（英文）》 2016年第10卷第1期页码 141-149 doi: 10.1007/s11783-014-0696-3

摘要： China has become the largest producer of crude steel in the world since 1996, which places the country under huge pressure in terms of resources, energy, and the environment. Examining the driver of steel demand is of great significance to the structural adjustment and sustainable development of the steel industry. The researchers calculate the steel demand in China from 2000 to 2009 based on three sinks (steel stock, export, and loss) by taking the four stages of steel life cycle (production, fabrication and manufacturing, use, and waste management and recycling) as the study object. The researchers conclude that addition to in-use stock is the main driver of steel demand and that the 10-year average addition to in-use stock accounted for 77% of the steel sinks, in which 55% of the addition occurs in the building sector, and the steel for this segment is of low strength with large consumption. Based on the analysis of existing policies, the researchers propose that the steel demand structure will develop toward diversification and that the building sector will realize the upgrade of products as soon as possible to improve construction quality. Under the pressure of rising cost for imported resources, the export ratio of steel products should be controlled appropriately. Thus, recycling economy should be developed to reduce steel losses.

关键词： steel demand driver Material Flow Analysis (MFA) Substance Flow Analysis (SFA) addition to in-use stock steel policy

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含能材料——新型合成和诊断技术

罗胜年, Michael Gozin

《工程（英文）》 2020年第6卷第9期页码 974-975 doi: 10.1016/j.eng.2020.07.002

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Effect of short-term atrazine addition on the performance of an anaerobic/anoxic/oxic process

Changyong WU, Xiaoling LI, Zhiqiang CHEN, Yongzhen PENG,

《环境科学与工程前沿（英文）》 2010年第4卷第2期页码 150-156 doi: 10.1007/s11783-010-0020-9

摘要： In this study, an anaerobic/anoxic/oxic (AO) wastewater treatment process was implemented to treat domestic wastewater with short-term atrazine addition. The results provided an evaluation on the effects of an accidental pollution on the operation of a wastewater treatment plant (WWTP) in relation to Chemical Oxygen Demand (COD) and biological nutrient removal. Domestic wastewater with atrazine addition in 3 continuous days was treated when steady biological nutrient removal was achieved in the AO process. The concentrations of atrazine were 15, 10, and 5mg·L on days 1, 2 and 3, respectively. The results showed that atrazine addition did not affect the removal of COD. The specific NH NO reduction rate decreased slightly due to the short-term atrazine addition. However, it did not affect the nitrogen removal due to the high nitrification and denitrification capacity of the system. Total nitrogen (TN) removal was steady, and more than 70% was removed during the period studied. The phosphorus removal rate was not affected by the short-term addition of atrazine under the applied experimental conditions. However, more poly-hydroxy-alkanoate (PHA) was generated and utilized during atrazine addition. The results of the oxygen uptake rate (OUR) showed that the respiration of nitrifiers decreased significantly, while the activity of carbon utilizers had no obvious change with the atrazine addition. Atrazine was not removed with the AO process, even via absorption by the activated sludge in the process of the short-term addition of atrazine.

关键词： biological nutrient removal atrazine anaerobic/anoxic/oxic (A2O) process oxygen demand removal oxygen uptake rate (OUR)

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Gene-editing in plants no longer requires tissue culture

Yi ZHANG, Michael PALMGREN

《农业科学与工程前沿（英文）》 2020年第7卷第2期页码 229-230 doi: 10.15302/J-FASE-2020330

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精准烧伤医学：分子工程科学应用

Kristen Jakubowski, Michael Poellmann, Raphael C. Lee

《工程（英文）》 2015年第1卷第3期页码 280-281 doi: 10.15302/J-ENG-2015073

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Hydration, microstructure and autogenous shrinkage behaviors of cement mortars by addition of superabsorbent

Beibei SUN, Hao WU, Weimin SONG, Zhe LI, Jia YU

《结构与土木工程前沿（英文）》 2020年第14卷第5期页码 1274-1284 doi: 10.1007/s11709-020-0656-x

摘要： Superabsorbent Polymer (SAP) has emerged as a topic of considerable interest in recent years. The present study systematically and quantitively investigated the effect of SAP on hydration, autogenous shrinkage, mechanical properties, and microstructure of cement mortars. Influences of SAP on hydration heat and autogenous shrinkage were studied by utilizing TAM AIR technology and a non-contact autogenous shrinkage test method. Scanning Electron Microscope (SEM) was employed to assess the microstructure evolution. Although SAP decreased the peak rate of hydration heat and retarded the hydration, it significantly increased the cumulative heat, indicating SAP helps promote the hydration. Hydration promotion caused by SAP mainly occurred in the deceleration period and attenuation period. SAP can significantly mitigate the autogenous shrinkage when the content ranged from 0 to 0.5%. Microstructure characteristics showed that pores and gaps were introduced when SAP was added. The microstructure difference caused by SAP contributed to the inferior mechanical behaviors of cement mortars treated by SAP.

关键词： Superabsorbent Polymer mechanical properties hydration heat autogenous shrinkage microstructure

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Yield-height correlation and QTL localization for plant height in two lowland switchgrass populations

MAKAJU, Yanqi WU, Michael P. ANDERSON, Vijaya G. KAKANI, Michael W.

《农业科学与工程前沿（英文）》 2018年第5卷第1期页码 118-128 doi: 10.15302/J-FASE-2018201

摘要： Switchgrass ( L.), as a model herbaceous crop species for bioenergy production, is targeted to improve biomass yield and feedstock quality. Plant height is a major component contributing to biomass yield. Accordingly, the objectives of this research were to analyze phenotypic variation for biomass and plant height and the association between them and to localize associated plant height QTLs. Two lowland switchgrass mapping populations, one selfed and another hybrid population established in the field at Perkins and Stillwater, Oklahoma, were deployed in the experiment for two years post establishment. Large genetic variation existed for plant biomass and height within the two populations. Plant height was positively correlated with biomass yield in the selfed population ( = 0.39, <0.0001) and the hybrid population ( = 0.41, <0.0001). In the selfed population, a joint analysis across all environments revealed 10 QTLs and separate analysis for each environment, collectively revealed 39 QTLs related to plant height. In the hybrid population, the joint analysis across overall environments revealed 35 QTLs and the separate analysis for each environment revealed 38 QTLs. The findings of this research contribute new information about the genetic control for plant height and will be useful for future plant breeding and genetic improvement programs in lowland switchgrass.

关键词： yield-height QTL localization lowland switchgrass

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Mass loss and nutrient dynamics during litter decomposition in response to warming and nitrogen addition

Haiyan REN, Jie QIN, Baolong YAN, Alata, Baoyinhexige, Guodong HAN

《农业科学与工程前沿（英文）》 2018年第5卷第1期页码 64-70 doi: 10.15302/J-FASE-2017194

摘要： Plant litter decomposition has been studied extensively in the context of both warming and increased atmospheric nitrogen deposition. However, the temporal patterns of mass loss and nutrient release in response to warming and nitrogen addition remain unclear. A 2-year decomposition experiment aimed to examine the effects of warming and nitrogen addition on decomposition rate, and nitrogen and phosphorus dynamics. The effects of warming and nitrogen addition on decomposition of litter of , a dominant species in a desert steppe of northern China, were studied. Warming and nitrogen addition significantly enhanced litter mass loss by 10% and 16%, respectively, and moreover promoted nitrogen and phosphorus release from the litter in the first year of decomposition, followed by an immobilization period. The interactive effects of warming and nitrogen addition on mass loss, nitrogen and phosphorus concentrations of litter were also found during the decomposition. This study indicates that warming and nitrogen addition increased litter mass loss through altering litter quality. These findings highlight that interactions between climate change and other global change factors could be highly important in driving decomposition responses.

关键词： climate warming grassland litter decomposition nitrogen deposition nutrient release

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Conceptual design of compliant mechanisms using level set method

Shi-kui CHEN, Michael Yu WANG

《机械工程前沿（英文）》 2006年第1卷第2期页码 131-145 doi: 10.1007/s11465-006-0018-y

摘要： We propose a level set method-based framework for the conceptual design of compliant mechanisms. In this method, the compliant mechanism design problem is recast as an infinite dimensional optimization problem, where the design variable is the geometric shape of the compliant mechanism and the goal is to find a suitable shape in the admissible design space so that the objective functional can reach a minimum. The geometric shape of the compliant mechanism is represented as the zero level set of a one-higher dimensional level set function, and the dynamic variations of the shape are governed by the Hamilton-Jacobi partial differential equation. The application of level set methods endows the optimization process with the particular quality that topological changes of the boundary, such as merging or splitting, can be handled in a natural fashion. By making a connection between the velocity field in the Hamilton-Jacobi partial differential equation with the shape gradient of the objective functional, we go further to transform the optimization problem into that of finding a steady-state solution of the partial differential equation. Besides the above-mentioned methodological issues, some numerical examples together with prototypes are presented to validate the performance of the method.

关键词： splitting minimum dimensional optimization Hamilton-Jacobi topological

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Does financial development lower energy intensity?

Philip Kofi ADOM, Michael Owusu APPIAH, Mawunyo Prosper AGRADI

《能源前沿（英文）》 2020年第14卷第3期页码 620-634 doi: 10.1007/s11708-019-0619-x

摘要： The growth-induced effects of financial development have been well-established in the empirical literature, as well as the significance of financial development to energy demand behavior. However, the empirical evidence on the relationship between financial development and energy intensity remains sparse in the literature. Given the multifaceted nature of the effects of financial development, the proposed relationship seems a complex one and warrants an empirical investigation. Using the case of Ghana, this study provides an empirical answer to the question: does financial development lower energy intensity? To provide solid grounds for either rejection or acceptance of the null hypothesis, this study performed several robustness checks. Generally, the evidence revealed that financial development lowers energy intensity. Further, the results revealed that the price of energy, trade liberalization and industry structure play significant roles. These results have important implications for the design of macro energy efficiency policies and the creation of a ‘Green Bank’.

关键词： financial development energy intensity energy efficiency Ghana

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Kinetics of microwave-enhanced oxidation of phenol by hydrogen peroxide

Deming ZHAO, Jie CHENG, Michael R. HOFFMANN

《环境科学与工程前沿（英文）》 2011年第5卷第1期页码 57-64 doi: 10.1007/s11783-010-0251-9

摘要： Aqueous solutions of phenol were oxidized by hydrogen peroxide assisted by microwave (MW) irradiation. A simple kinetic model for the overall degradation of phenol in the presence of excess H O is proposed in which the degradation rate of phenol is expressed as a linear function of the concentrations of phenol and H O . A detailed parametric study showed that the degradation rate of phenol increased with increasing [H O ] until saturation was observed. Phenol degradation followed apparent zero-order kinetics under MW radiation or H O oxidation. However, after 90 min of irradiation, the observed kinetics shifted to pseudo first order. The overall reaction rates were significantly enhanced in the combined MW/H O system, mainly because microwave could accelerate H O to generate hydroxyl radical ( OH) and other reactive oxygen intermediates. The observed synergetic effects of the MW/H O process resulted in an increased in the net reaction rate by a factor of 5.75. When hydrogen peroxide is present in a large stoichiometric excess, the time required to achieve complete mineralization is reduced significantly.

关键词： microwave (MW) irradiation hydrogen peroxide phenol synergetic effects kinetic model

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species associated with eucalypt diseases in southern China

Shuaifei CHEN, Qianli LIU, Guoqing LI, Michael J. WINGFIELD

《农业科学与工程前沿（英文）》 2017年第4卷第4期页码 433-447 doi: 10.15302/J-FASE-2017173

摘要： The genus includes several important pathogens of species of and , mainly causing leaf and shoot blight. Recently, extensive shoot and leaf dieback and stem cankers suspected to be diseases have been found on young trees in Guangdong and Hainan Provinces. The occurrence of species and their association with eucalypt hosts within China needs to be investigated for tree diseases management. The isolates from the diseased samples were identified based on their morphological structures and phylogenetic analyses with DNA sequence data for the internal transcribed spacer region and large ribosome subunit RNA of the nuclear rDNA. This work revealed that three species of were present: from , from , both isolated from young eucalypt leaves and shoots in Guangdong Province, and , which was isolated from stem cankers of at four different sites across Guangdong and Hainan Provinces. These results confirmed that agents were associated with the diseases occurring on eucalypt hosts in South China. This is the first report of in Asia and the first report of in China on trees.

关键词： Corymbia Eucalyptus forest pathogens plantations Myrtaceae

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XFEM schemes for level set based structural optimization

Li LI, Michael Yu WANG, Peng WEI

《机械工程前沿（英文）》 2012年第7卷第4期页码 335-356 doi: 10.1007/s11465-012-0351-2

摘要：

In this paper, some elegant extended finite element method (XFEM) schemes for level set method structural optimization are proposed. Firstly, two- dimension (2D) and three-dimension (3D) XFEM schemes with partition integral method are developed and numerical examples are employed to evaluate their accuracy, which indicate that an accurate analysis result can be obtained on the structural boundary. Furthermore, the methods for improving the computational accuracy and efficiency of XFEM are studied, which include the XFEM integral scheme without quadrature sub-cells and higher order element XFEM scheme. Numerical examples show that the XFEM scheme without quadrature sub-cells can yield similar accuracy of structural analysis while prominently reducing the time cost and that higher order XFEM elements can improve the computational accuracy of structural analysis in the boundary elements, but the time cost is increasing. Therefore, the balance of time cost between FE system scale and the order of element needs to be discussed. Finally, the reliability and advantages of the proposed XFEM schemes are illustrated with several 2D and 3D mean compliance minimization examples that are widely used in the recent literature of structural topology optimization. All numerical results demonstrate that the proposed XFEM is a promising structural analysis approach for structural optimization with the level set method.

关键词： structural optimization level set method extended finite element method (XFEM) computational accuracy and efficiency