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Temperature control of transfer roller’s bearing based on finite element analysis

Peng ZHANG, Yourong LI, Han XIAO

《机械工程前沿（英文）》 2009年第4卷第2期页码 215-218 doi: 10.1007/s11465-009-0026-9

摘要： After a heat preservation cover is installed on the main rolling line, the heat dissipation environment of the transfer roller working on the heat preservation cover is changed. To ensure the normal production, a reasonable working jet capacity of the roller neck is derived. First, a globe model of the transfer roller is built for finite element analysis. Second, the sub-model of the fixed end bearing is built and the boundary condition of the sub-model is supplied by the results of the globe model. The analysis result of the sub-model shows that the temperature of the transfer roller bearing exceeds 85°C a rolling periodicity later. With finite element analysis, the heat flux is obtained and the minimum working jet capacity is derived.

关键词： transfer roller bearing finite element analysis sub-model temperature control

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含稀释剂的Al-Cr2sub>O3sub>体系燃烧合成反应热力学分析与反应模型

张衍诚,潘冶,张传

《中国工程科学》 2004年第6卷第6期页码 63-67

摘要：

对含稀释剂Al203和Cr203的Al-Cr203体系燃烧合成反应进行了热力学计算与分析，讨论了起始反应温度T0、稀释剂Al2O3和Cr2O3的含量对绝热反应温度7^的影响，并得出T0与Tad在特定温度段上的近似线性关系以及该关系在指导材料成分设计上的应用；揭示了反应驱动力—&mdash

关键词：金属陶瓷燃烧合成 Al-Cr203体系热力学反应模型

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Initiation of Setaria as a model plant

Xianmin DIAO,James SCHNABLE,Jeffrey L. BENNETZEN,Jiayang LI

《农业科学与工程前沿（英文）》 2014年第1卷第1期页码 16-20 doi: 10.15302/J-FASE-2014011

摘要： Model organisms such as Arabidopsis ( ) and rice ( ) have proven essential for efficient scientific discovery and development of new methods. With the diversity of plant lineages, some important processes such as C photosynthesis are not found in either Arabidopsis or rice, so new model species are needed. Due to their small diploid genomes, short life cycles, self-pollination, small adult statures and prolific seed production, domesticated foxtail millet ( ) and its wild ancestor, green foxtail ( ), have recently been proposed as novel model species for functional genomics of the Panicoideae, especially for study of C photosynthesis. This review outlines the development of these species as model organisms, and discusses current challenges and future potential of a Setaria model.

关键词： Setaria foxtail millet C₄ photosynthesis model organism

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分形模型参数与粗糙度参数Rasub>关系的研究

潘玉良,吴立群,张云电

《中国工程科学》 2004年第6卷第5期页码 49-51

摘要：

介绍了W－M分形模型参数（D,G,γ）的物理含义，研究了分形参数（D,G,γ）与粗糙度参数Rasub>之间的联系，导出了分形参数（D,G,γ）与粗糙度参数Rasub>关系式，用数值分析拟合方法验证了关系式的正确性。

关键词： W－M分形模型分形参数粗糙度Rasub>

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emissions through demand side regulation: Implications from multi-regional input–output linear programming model

《工程管理前沿（英文）》 2022年第9卷第3期页码 452-461 doi: 10.1007/s42524-022-0209-1

摘要： This study combines multi-regional input–output (MRIO) model with linear programming (LP) model to explore economic structure adjustment strategies for the reduction of carbon dioxide (CO₂) emissions. A particular feature of this study is the identification of the optimal regulation sequence of final products in various regions to reduce CO₂ emissions with the minimum loss in gross domestic product (GDP). By using China’s MRIO tables 2017 with 28 regions and 42 economic sectors, results show that reduction in final demand leads to simultaneous reductions in GDP and CO₂ emissions. Nevertheless, certain demand side regulation strategy can be adopted to lower CO₂ emissions at the smallest loss of economic growth. Several key final products, such as metallurgy, nonmetal, metal, and chemical products, should first be regulated to reduce CO₂ emissions at the minimum loss in GDP. Most of these key products concentrate in the coastal developed regions in China. The proposed MRIO–LP model considers the inter-relationship among various sectors and regions, and can aid policy makers in designing effective policy for industrial structure adjustment at the regional level to achieve the national environmental and economic targets.

关键词： CO₂ emissions demand side regulation multi-regional input–output model linear programming model

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A multi-scale model for CO

G. X. WANG, X. R. WEI, V. RUDOLPH, C. T. WEI, Y. QIN

《化学科学与工程前沿（英文）》 2009年第3卷第1期页码 20-25 doi: 10.1007/s11705-009-0138-0

摘要： This paper presents a multi-scale model to simulate the multicomponent gas diffusion and flow in bulk coals for CO sequestration enhanced coalbed methane recovery. The model is developed based on a bi-dispersed structure model by assuming that coal consists of microporous micro-particles, meso/macro-pores and open microfractures. The bi-disperse diffusion theory and the Maxwell-Stefan approach were incorporated in the model, providing an improved simulation of the CH —CO /CH —N counter diffusion dynamics. In the model, the counter diffusion process is numerically coupled with the flow of the mixture gases occurring within macro-pores or fractures in coal so as to account for the interaction between diffusion and flow in gas transport through coals. The model was validated by both experimental data from literature and our CO flush tests, and shows an excellent agreement with the experiments. The results reveal that the gas diffusivities, in particular the micro-pore diffusivities are strongly concentration-dependent.

关键词： multi-scale model gas transport coal coalbed methane CO₂ sequestration

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一种融合多特征聚类与神经网络的PM2.5sub>小时浓度预测新模型及其在中国城市的应用 Article

刘辉, 龙治豪, 段铸, 施惠鹏

《工程（英文）》 2020年第6卷第8期页码 944-956 doi: 10.1016/j.eng.2020.05.009

摘要：

PM2.5sub>浓度预测对空气污染物早期预警具有重要意义。本文提出一种改进的PM2.5sub>浓度多步预测模型，即多特征聚类分解(MCD)-回声状态网络(ESN)-粒子群优化(PSO)混合模型。该模型包括分解预测部分和优化预测部分。在MCD方法中，采用RSAR算法选择重要的空气污染物变量，使用KC算法对所得变量进行聚类，利用EWT算法将PM2.5sub>浓度序列的聚类结果分解为多个子层。利用我国4个不同城市的真实PM2.5sub>浓度数据，验证了所提出模型的有效性。实验结果表明，所提出预测模型适用于PM2.5sub>浓度的多步高精度预测，具有比基准模型更优的预测性能。

关键词： PM2.5sub>2.5浓度预测 PM2.5sub>2.5浓度聚类经验小波分解多步预测

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Multi-objective dynamic optimization model for China’s road transport energy technology switching

Dan GAO , Zheng LI , Feng FU , Linwei MA

《能源前沿（英文）》 2009年第3卷第3期页码 247-253 doi: 10.1007/s11708-009-0048-3

摘要： Deducting the future switching of the road transport energy technology is one of the key preconditions for relative technology development planning. However, one of the difficulties is to address the issue of multi-objective and conflicting constrains, e.g., minimizing the climate mitigation or minimizing economic cost. In this paper, a dynamic optimization model was established, which can be used to analyze the road transport energy technology switching under multi-objective constrains. Through one case study, a series of solutions could be derived to provide decision-makers with the flexibility to choose the appropriate solution with respect to the given situation.

关键词： technology switching transport energy system multi-objective CO₂ mitigation

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Does environmental infrastructure investment contribute to emissions reduction? A case of China

Xiaoqian SONG, Yong GENG, Ke LI, Xi ZHANG, Fei WU, Hengyu PAN, Yiqing ZHANG

《能源前沿（英文）》 2020年第14卷第1期页码 57-70 doi: 10.1007/s11708-019-0654-7

摘要： Environmental infrastructure investment (EII) is an important environmental policy instrument on responding to greenhouse gas (GHG) emission and air pollution. This paper employs an improved stochastic impact by regression on population, affluence and technology (STRIPAT) model by using panel data from 30 Chinese provinces and municipalities for the period of 2003–2015 to investigate the effect of EII on CO emissions, SO emissions, and PM pollution. The results indicate that EII has a positive and significant effect on mitigating CO emission. However, the effect of EII on SO emission fluctuated although it still contributes to the reduction of PM pollution through technology innovations. Energy intensity has the largest impact on GHG emissions and air pollution, followed by GDP per capita and industrial structure. In addition, the effect of EII on environmental issues varies in different regions. Such findings suggest that policies on EII should be region-specific so that more appropriate mitigation policies can be raised by considering the local realities.

关键词： environmental infrastructure investment (EII) CO₂ emission SO₂ emission PM_2.5 pollution stochastic impact by regression on population affluence and technology (STIRPAT) model governance

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Temporal variation of PM-associated health effects in Shijiazhuang, Hebei

《环境科学与工程前沿（英文）》 2021年第15卷第5期 doi: 10.1007/s11783-020-1376-0

摘要：

•Annual mean PM_2.5 in Shijiazhuang were 87, 95, and 82 µg/m³ in 2015–2017.

关键词： PM_2.5 Health effects Integrated exposure-response model Shijiazhuang

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从氢原子质子化模型计算H2sub>⁺的结构参数

陈景

《中国工程科学》 2004年第6卷第11期页码 29-32

摘要：

对氢分子离子提出了氢原子质子化的结构模型，从微观时标和宏观时标分析了H2sub>⁺中库仑吸引力和两核排斥力的动态平衡，认为氢原子畸变后的电子云在两核中点产生e/8的电荷重心时可以束缚住一个裸质子；据此推导出键长、键能及力常数的计算公式；使用原子单位分别获得Resub>=2 au，Desub>=0.109 735 au，k=0.109

关键词：氢分子离子键长键能力常数

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Coupling the porous conditional moment closure with the random pore model: applications to gasification

D. N. SAULOV, C. R. CHODANKA, M. J. CLEARY, A. Y. KLIMENKO

《化学科学与工程前沿（英文）》 2012年第6卷第1期页码 84-93 doi: 10.1007/s11705-011-1164-2

摘要： Gasification of coal or biomass with in situ CO capture simultaneously allows production of clean hydrogen at relatively low cost and reduced emission of CO into the atmosphere. Clearly, this technology has a great potential for a future carbon constrained economy. Therefore, the development of a comprehensive, physically-based gasifier model is important. The sub-models that describe reactive transport processes in coal particles as well as in particles of CO sorbent material are among the key sub-models, which provide a necessary input for an overall gasifier model. Both coal and sorbent are materials that have complicated pore structures. The porous conditional moment closure (PCMC) model proves to be adequate for modeling reactive transport through porous media with fixed pore structure. Consumption of coal in the heterogeneous gasification reaction, however, widens the pores and reduces the surface area available for this reaction. At the same time, formation of a carbonate layer narrows the pores in the sorbent material and reduces the reaction rate of CO sorption. In both cases the pore structures are affected. Such changes are not taken into account in the existing PCMC model. In this study, we obtain the parameters of the diffusive tracer distribution based on the pore size distribution given by the widely applied random pore model (RPM), while coupling PCMC with RPM. Such coupling allows taking into account changes in pore structure caused by heterogeneous reactions and thus improves the accuracy of these key sub-models.

关键词： gasification CO₂ capture PCMC RPM

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Developing the QSPR model for predicting the storage lipid/water distribution coefficient of organic

Miao Li, Jian Li, Yuchen Lu, Cenyang Han, Xiaoxuan Wei, Guangcai Ma, Haiying Yu

《环境科学与工程前沿（英文）》 2021年第15卷第2期 doi: 10.1007/s11783-020-1316-z

摘要： Abstract • A predictive model for storage lipid/water distribution coefficient was developed. • The model yields outstanding fitting performance, robustness, and predictive ability. • Hydrophobic and electrostatic interactions and molecular size dominate log Klip/w. • The model can be used in a wide application domain to predict log Klip/w values. The distribution of organic compounds in stored lipids affects their migration, transformation, bioaccumulation, and toxicity in organisms. The storage lipid/water distribution coefficient (log Klip/w) of organic chemicals, which quantitatively determines such distribution, has become a key parameter to assist their ecological security and health risk. Due to the impossibility to measure Klip/w values for a huge amount of chemicals, it is necessary to develop predictive approaches. In this work, a quantitative structure-property relationship (QSPR) model for estimating log Klip/w values of small organic compounds was constructed based on 305 experimental log Klip/w values. Quantum chemical descriptors and n-octanol/water partitioning coefficient were employed to characterize the intermolecular interactions that dominate log Klip/w values. The hydrophobic and electrostatic interactions and molecular size have been found to play important roles in governing the distribution of chemicals between lipids and aqueous phases. The regression (R2 = 0.959) and validation (Q2 = 0.960) results indicate good fitting performance and robustness of the developed model. A comparison with the predictive performance of other commercial software further proves the higher accuracy and stronger predictive ability of the developed Klip/w predictive model. Thus, it can be used to predict the Klip/w values of cycloalkanes, long-chain alkanes, halides (with fluorine, chlorine, and bromine as substituents), esters (without phosphate groups), alcohols (without methoxy groups), and aromatic compounds.

关键词： Storage lipid/water distribution coefficient log K_lip/w Organic compounds QSPR Quantum chemical descriptors

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Reduction kinetics of SrFeO/CaO∙MnO nanocomposite as effective oxygen carrier for chemical looping partial oxidation of methane

《化学科学与工程前沿（英文）》 2022年第16卷第12期页码 1726-1734 doi: 10.1007/s11705-022-2188-5

摘要： Chemical looping reforming of methane is a novel and effective approach to convert methane to syngas, in which oxygen transfer is achieved by a redox material. Although lots of efforts have been made to develop high-performance redox materials, a few studies have focused on the redox kinetics. In this work, the kinetics of SrFeO_3−δ–CaO∙MnO nanocomposite reduction by methane was investigated both on a thermo-gravimetric analyzer and in a packed-bed microreactor. During the methane reduction, combustion occurs before the partial oxidation and there exists a transition between them. The weight loss due to combustion increases, but the transition region becomes less inconspicuous as the reduction temperature increased. The weight loss associated with the partial oxidation is much larger than that with combustion. The rate of weight loss related to the partial oxidation is well fitted by the Avrami–Erofeyev equation with n = 3 (A3 model) with an activation energy of 59.8 kJ∙mol^‒1. The rate law for the partial oxidation includes a solid conversion term whose expression is given by the A3 model and a methane pressure-dependent term represented by a power law. The partial oxidation is half order with respect to methane pressure. The proposed rate law could well predict the reduction kinetics; thus, it may be used to design and/or analyze a chemical looping reforming reactor.

关键词： chemical looping reforming SrFeO_3−δ/CaO·MnO nanocomposite reduction kinetics Avrami–Erofeyev model pressure-dependent term