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Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

《工程管理前沿（英文）》 2020年 第7卷 第2期   页码 248-258 doi: 10.1007/s42524-019-0069-5

摘要： During financial crisis, companies constantly need free cash flows to efficiently react to any uncertainty, thus ensuring solvency. Working capital requirement (WCR) has been recognized as a key factor for releasing tied up cash in companies. However, in literatures related to lot-sizing problem, WCR has only been studied in the single-level supply chain context. In this paper, we initially adopt WCR model for a multi-level case. A two-level (supplier–customer) model is established on the basis of the classic multi-level lot-sizing model integrated with WCR financing cost. To tackle this problem, we propose sequential and centralized approaches to solve the two-level case with a serial chain structure. The ZIO (Zero Inventory Ordering) property is further confirmed valid in both cases. This property allows us to establish a dynamic programming-based algorithm, which solves the problem in O(T ). Finally, numerical tests show differences in optimal plans obtained by both approaches and the influence of varying delays in payment on the WCR of both actors.

关键词： two-level ULS problem     lot-sizing     working capital requirement     ZIO property     infinite production capacity    

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Calculation of prestressed anchor segment by 3D infinite element

Yanfen WANG, Hongyang XIE, Yuanhan WANG

《结构与土木工程前沿（英文）》 2009年 第3卷 第1期   页码 63-66 doi: 10.1007/s11709-009-0006-5

摘要： Based on 1D infinite element theory, the coordinate transformation and shape function of 3D point-radiation 4-node infinite elements were derived. They were coupled with 8-node finite elements to compute the compressive deformation of the prestressed anchor segment. The results indicate that when the prestressed force acts on the anchor segment, the stresses and displacements in the rock around the anchor segment are concentrated in the zone center with the anchor axis and are subjected to exponential decay. Therefore, the stresses and the displacement spindles are formed. The calculation results of the infinite element are close to the theoretical results.

关键词： infinite element     prestressed anchor     couple     finite element    

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yielding and more stable rice genotypes in stress environments: fine-tuning a selection method using production

《农业科学与工程前沿（英文）》 doi: 10.15302/J-FASE-2023521

摘要：

● Score index methods readily discriminate genotypes adapted to a target environment.

关键词： Aerobic rice     breeding selection     drought resilience     production capacity index     resilience capacity index     stress score index     upland    

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seismic analysis for 2D oblique incident waves using exact free-field responses by frequency-based finite/infinite

《结构与土木工程前沿（英文）》 2022年 第16卷 第12期   页码 1530-1551 doi: 10.1007/s11709-022-0900-7

摘要： The seismic analysis of a viscoelastic half-space under two-dimensional (2D) oblique incident waves is carried out by the finite/infinite element method (FIEM). First, the frequency-domain exact solutions for the displacements and stresses of the free field are derived in general form for arbitrary incident P and SV waves. With the present formulation, no distinction needs to be made for SV waves with over-critical incident angles that make the reflected P waves disappear, while no critical angle exists for P waves. Next, the equivalent seismic forces of the earthquake (Taft Earthquake 1952) imposed on the near-field boundary are generated by combining the solutions for unit ground accelerations with the earthquake spectrum. Based on the asymmetric finite/infinite element model, the frequency-domain motion equations for seismic analysis are presented with the key parameters selected. The results obtained in frequency and time domain are verified against those of Wolf’s, Luco and de Barros’ and for inversely computed ground motions. The parametric study indicated that distinct phase difference exists between the horizontal and vertical responses for SV waves with over-critical incident angles, but not for under-critical incident angles. Other observations were also made for the numerical results inside the text.

关键词： oblique incident waves     critical angle     half-space     finite/infinite element approach     seismic response analysis    

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大体积混凝土受寒潮袭击时半无限平面问题的无限平面化

黄达海,王从峰

《中国工程科学》 2002年 第4卷 第7期   页码 33-39

摘要：

在分析混凝土表面裂缝特点的基础上，针对受寒潮袭击中的大体积混凝土，提出表面裂缝问题的半无限平面假设。利用混凝土传热的延迟性质，研究了任意降温过程中半无限平面问题无限平面化的条件。采用叠加原理，提出了环境温度任意下降时混凝土表面温度及表层温度计算的新方法。利用400mm×400 mm×220 mm块状试件，构造了混凝土表面开裂问题的半无限平面模型。在室外环境下，对混凝土表面温度与表层温度进行了连续测量，并对该方法进行了验证。试验结果表明，在环境温度单调下降的条件下，对混凝土受寒潮袭击时的半无限平面问题进行无限平面化处理是可行的。

关键词： 混凝土     表层温度     半无限平面问题     降温过程     条件等价性     模型试验    

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Measurement of activity coefficients at infinite dilution for hydrocarbons in imidazolium-based ionic

ZHU Jiqin, YU Yanmei, CHEN Jian, FEI Weiyang

《化学科学与工程前沿（英文）》 2007年 第1卷 第2期   页码 190-194 doi: 10.1007/s11705-007-0035-3

摘要： The separations of olefin/paraffin, aromatic/aliphatic hydrocarbons or olefin isomers using ionic liquids instead of volatile solvents have interested many researchers. Activity coefficients γ at infinite dilution of a solute in ionic liquid are generally used in the selection of solvents for extraction or extractive distillation. In fact, the measurement of γ by gas-liquid chromatography is a speedy and cost-saving method. Activity coefficients at infinite dilution of hydrocarbon solutes, such as alkanes, hexenes, alkylbenzenes, styrene, in 1-allyl-3-methylimidazolium tetrafluoroborate ([AMIM][BF]) and 1-butyl-3-methyl imidazolium hexafluorophosphate ([BMIM][PF6]), 1-isobutenyl-3-methylimidazolium tetrafluoroborate ([MPMIM][BF]) and [MPMIM][BF]-AgBF have been determined by gas-liquid chromatography using ionic liquids as stationary phase. The measurements were carried out at different temperatures from 298 to 318 K. The separating effects of these ionic liquids for alkanes/hexane, aliphatic hydrocarbons/benzene and hexene isomers have been discussed. The hydrophobic parameter, dipole element, frontier molecular orbital energy gap and hydration energy of these hydrocarbons were calculated with the PM3 semi-empirical quantum chemistry method. The quantitative relations among the computed structure parameters and activity coefficients at infinite dilution were also developed. The experimental activity coefficient data are consistent with the correlated and predicted results using QSPR models.

关键词： cost-saving     consistent     coefficient     measurement     separating    

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煤炭科学产能及发展战略初探

谢和平,钱鸣高,彭苏萍,胡省三,成玉琪,周宏伟

《中国工程科学》 2011年 第13卷 第6期   页码 44-50

摘要：

针对我国目前煤炭产能的主要特点及问题，提出了煤炭科学产能的概念，以促进我国煤炭工业可持续发展，扭转目前我国煤炭生产“高危、污染、粗放、无序”的行业形象，并根据我国煤炭资源的特点，对我国煤炭科学产能的规模、布局和发展潜力进行了全面论述，同时预测了2030年、2050年前后的煤炭科学产能总量，提出了我国煤炭向科学产能发展的战略部署和措施建议。

关键词： 煤炭生产     科学产能     战略规划    

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Thermally developing forced convection and the corresponding thermal stresses in a porous plate channel

YANG Xiao, LIU Xuemei

《机械工程前沿（英文）》 2007年 第2卷 第1期   页码 57-61 doi: 10.1007/s11465-007-0009-7

摘要： Based on the Darcy fluid model, by considering the effects of viscous dissipation due to the interaction between solid skeleton and pore fluid flow and thermal conduction in the direction of the fluid flow, the thermally developing forced convection of the local thermal equilibrium and the corresponding thermal stresses in a semi-infinite saturated porous plate channel are investigated in this paper. The expressions of temperature, local Nusselt number and corresponding thermal stresses are obtained by means of the Fourier series, and the distributions of the same are also shown. Furthermore, influences of the P晱let number () and Brinkman number () on temperature, Nusselt number () and thermal stress are revealed numerically.

关键词： semi-infinite saturated     direction     interaction     skeleton     thermal equilibrium    

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The calculation of equivalence factor for ecological footprints in China: a methodological note

Moucheng LIU,Wenhua LI,Dan ZAHNG,Ning SU

《环境科学与工程前沿（英文）》 2015年 第9卷 第6期   页码 1015-1024 doi: 10.1007/s11783-014-0670-0

摘要： The Ecological Footprint (EF), a physical indicator to measure the extent of humanity’s use of natural resources, has gained much attention since it was first used by Wackernagel and Rees in 1996. In order to appraise land area types with different levels of productivity, they introduced the concept of an equivalence factor. This relates to the average primary biomass productivities of different types of land (i.e. arable land, pasture, forest, water/fishery, built-up land and fossil energy land) to the regional average primary biomass productivity of all land types in a given year. Hence, the equivalence factor is an important parameter in the EF model and it directly affects the reliability of all results. Thus, this article calculates equivalence factors on the national and provincial levels in China based on Net Primary Production (NPP) from MODIS 1 km data in 2008. Firstly, based on the Light Utility Efficiency and CASA model, the NPP of different biologically productive lands of China and of different provinces was calculated. Secondly, China’s equivalence factor for 6 land area types was calculated based on NPP: arable land and built-up land has an equivalence factor of 1.71, forest and fossil energy land has a factor of 1.41, pasture has a factor of 0.44 and water/fishery 0.35; Finally, the equivalence factor of 6 land area types in different provinces was also calculated. The NPP of each ecosystem type varies along with the equivalence factor in different provinces. However, the ranking of the equivalence factors in different provinces remain the same, with that of arable land being the largest, and the water/fishery being the smallest.

关键词： ecological footprint     equivalence factor     net primary production     biological capacity     land types    

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Efficient acetylene/carbon dioxide separation with excellent dynamic capacity and low regeneration energy

《化学科学与工程前沿（英文）》   页码 1616-1622 doi: 10.1007/s11705-022-2183-x

摘要： Adsorptive separation of acetylene/carbon dioxide mixtures by porous materials is an important and challenging task due to their similar sizes and physical properties. Here, remarkable acetylene/carbon dioxide separation featuring a high dynamic breakthrough capacity for acetylene (4.3 mmol·g–1) as well as an ultralow acetylene regeneration energy (29.5 kJ·mol–1) was achieved with the novel TiF62–-pillared material ZU-100 (TIFSIX-bpy-Ni). Construction of a pore structure with abundant TiF62– anion sites and pores with appropriate sizes enabled formation of acetylene clusters through hydrogen bonds and intermolecular interactions, which afforded a high acetylene capacity (8.3 mmol·g–1) and high acetylene/carbon dioxide uptake ratio (1.9) at 298 K and 1 bar. Moreover, the NbO52– anion-pillared material ZU-61 investigated for separation of acetylene/carbon dioxide. In addition, breakthrough experiments were also conducted to further confirm the excellent dynamic acetylene/carbon dioxide separation performance of ZU-100.

关键词： adsorption     acetylene/carbon dioxide separation     dynamic capacity     anion-pillared hybrid material    

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Buffer capacity of granular matter to impact of spherical projectile based on discrete element method

Ying YAN, Pengfei LI, Shunying JI

《结构与土木工程前沿（英文）》 2013年 第7卷 第1期   页码 50-54 doi: 10.1007/s11709-013-0186-x

摘要： Granular matter possesses impact-absorbing property due to its energy dissipation character. To investigate the impact-absorbing capacity of granular matter, the discrete element method (DEM) is adopted to simulate the impact of a spherical projectile on to a granular bed. The dynamic responses of the projectile are obtained for both thin and thick granular bed. The penetration depth of the projectile and the first impact peak are investigated with different bed thicknesses and impact velocities. Determining a suitable bed thickness is crucial to the buffering effect of granular matter. The first impact peak is independent of bed thickness when the thickness is larger than the critical thickness.

关键词： granular matter     impact peak     buffer capacity     discrete element method     critical thickness    

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Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

《环境科学与工程前沿（英文）》 2016年 第10卷 第1期   页码 114-128 doi: 10.1007/s11783-014-0669-6

摘要： A revised concept for urban water metabolism (UWM) is presented in this study to address the inadequacies in current research on UWM and the problems associated with the traditional urban water metabolic process. Feedback loops can be analyzed to increase the water environmental carrying capacity (WECC) of the new urban water metabolism system (UWMS) over that of a traditional UWMS. An analysis of the feedback loops of an UWMS was used to construct a system dynamics (SD) model for the system under a WECC restriction. Water metabolic processes were simulated for different scenarios using the Tongzhou District in Beijing as an example. The results for the newly developed UWM case showed that a water environment of Tongzhou District could support a population of 1.1926 × 10 , an irrigation area of 375.521 km , a livestock of 0.7732 × 10 , and an industrial value added of ¥193.14 × 10 (i.e. about US$28.285× 10 ) in 2020. A sensitivity analysis showed that the WECC could be improved to some extent by constructing new sewage treatment facilities or by expanding the current sewage treatment facilities, using reclaimed water and improving the water circulation system.

关键词： urban water metabolism system (UWMS)     system dynamic simulation     water environmental carrying capacity (WECC)     feedback loops     bilateral control    

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Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

《环境科学与工程前沿（英文）》 2022年 第16卷 第1期   页码 3-3 doi: 10.1007/s11783-021-1437-z

摘要：

Microplastics (MPs) are widely present in a variety of environmental media and have attracted more and more attention worldwide. However, the effect of MPs on the interaction between heavy metals and soil, especially in soil solid fraction level, is not well understood. In this study, batch experiments were performed to investigate the adsorption characteristics of Cd in bulk soil and three soil solid fractions (i.e. particulate organo matter (POM), organic-mineral compounds (OMC), and mineral) with or without polypropylene (PP) MPs.

关键词： Polypropylene microplastics     Cadmium     Adsorption     POM     OMC     Mineral    

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Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

《结构与土木工程前沿（英文）》   页码 901-914 doi: 10.1007/s11709-023-0915-8

摘要： The integrity and bearing capacity of segment joints in shield tunnels are associated closely with the mechanical properties of the joints. This study focuses on the mechanical characteristics and mechanism of a bolted circumferential joint during the entire bearing process. Simplified analytical algorithms for four stress stages are established to describe the bearing behaviors of the joint under a compressive bending load. A height adjustment coefficient, α, for the outer concrete compression zone is introduced into a simplified analytical model. Factors affecting α are determined, and the degree of influence of these factors is investigated via orthogonal numerical simulations. The numerical results show that α can be specified as approximately 0.2 for most metro shield tunnels in China. Subsequently, a case study is performed to verify the rationality of the simplified theoretical analysis for the segment joint via numerical simulations and experiments. Using the proposed simplified analytical algorithms, a parametric investigation is conducted to discuss the factors affecting the ultimate compressive bending capacity of the joint. The method for optimizing the joint flexural stiffness is clarified. The results of this study can provide a theoretical basis for optimizing the design and prediciting the damage of bolted segment joints in shield tunnels.

关键词： shield tunnel     segment joint     joint structural model     failure mechanism    

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我国草原生产力

侯扶江,王春梅,娄珊宁,侯向阳,呼天明

《中国工程科学》 2016年 第18卷 第1期   页码 80-93 doi: 10.15302/J-SSCAE-2016.01.011

摘要：

分析我国草原植物生产和动物生产，比较国内外草原生产力。结果表明，在过去的30余年中，我国一部分草原产草量下降，局部变化不显著。世界草原对畜产品生产的贡献率为40.08 %，中等收入国家为67.35 %。全球24.1 %的牛肉和31.9 %的羊肉来自草原，低收入国家草原载畜量分别高出高收入国家和中等收入国家87.4 %和66.4 %，畜产品生产分别只有两者的37.3 %和71.9 %。适宜的放牧利用，可使我国的草原生产能力达到6.35×109畜产品单位（APU）；全国草原单纯依靠放牧每年可产肉2.959×106 t，占全国肉类总产量的3.5 %，占全国牛羊肉总产量的27.4 %。通过草原畜牧业的现代化转型可接近高收入国家水平，增产潜力约为50 %~200 %。

关键词： 草原生产力     产草量     放牧     载畜量     畜产品单位（APU）    

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标题 作者 时间 类型 操作

Two-level uncapacitated lot-sizing problem considering the financing cost of working capital requirement

Yuan BIAN, David LEMOINE, Thomas G. YEUNG, Nathalie BOSTEL

期刊论文

Calculation of prestressed anchor segment by 3D infinite element

Yanfen WANG, Hongyang XIE, Yuanhan WANG

期刊论文

yielding and more stable rice genotypes in stress environments: fine-tuning a selection method using production

期刊论文

seismic analysis for 2D oblique incident waves using exact free-field responses by frequency-based finite/infinite

期刊论文

大体积混凝土受寒潮袭击时半无限平面问题的无限平面化

黄达海,王从峰

期刊论文

Measurement of activity coefficients at infinite dilution for hydrocarbons in imidazolium-based ionic

ZHU Jiqin, YU Yanmei, CHEN Jian, FEI Weiyang

期刊论文

煤炭科学产能及发展战略初探

谢和平,钱鸣高,彭苏萍,胡省三,成玉琪,周宏伟

期刊论文

Thermally developing forced convection and the corresponding thermal stresses in a porous plate channel

YANG Xiao, LIU Xuemei

期刊论文

The calculation of equivalence factor for ecological footprints in China: a methodological note

Moucheng LIU,Wenhua LI,Dan ZAHNG,Ning SU

期刊论文

Efficient acetylene/carbon dioxide separation with excellent dynamic capacity and low regeneration energy

期刊论文

Buffer capacity of granular matter to impact of spherical projectile based on discrete element method

Ying YAN, Pengfei LI, Shunying JI

期刊论文

Dynamic simulation of urban water metabolism under water environmental carrying capacity restrictions

Weihua ZENG,Bo WU,Ying CHAI

期刊论文

Polypropylene microplastics alter the cadmium adsorption capacity on different soil solid fractions

期刊论文

Analytical algorithms of compressive bending capacity of bolted circumferential joint in metro shield

期刊论文

我国草原生产力

侯扶江,王春梅,娄珊宁,侯向阳,呼天明

期刊论文