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Functional trait differences between native bunchgrasses and the invasive grass

Huiqin HE, Thomas A. MONACO, Thomas A. JONES

《农业科学与工程前沿（英文）》 2018年第5卷第1期页码 139-147 doi: 10.15302/J-FASE-2017175

摘要： We conducted 30- and 60-d greenhouse experiments to compare functional traits of (invasive annual grass) and four perennial bunchgrasses under well-watered or drought conditions. Even under drought, experienced significantly less stress (i.e., higher xylem pressure potential and greater shoot water content, water use per day and water-use efficiency) and biomass production than the perennial grasses after 30 d. However, after 60 d, its superiority was reduced under infrequent watering. Differences among perennial grasses were more pronounced for physiological traits under infrequent watering and for morphological traits under frequent watering. (fast-growing species) had a higher transpiration rate, lower leaf temperature, and lower water-use efficiency than the other grasses after 30 d. In contrast, (slow-growing) had lower xylem pressure potential and higher leaf temperature than all other grasses under infrequent watering. Under frequent watering, shoot dry mass and specific leaf area of was matched by (moderate-growing species). Our results indicate that multiple-species plantings or seedings are necessary to foster greater weed resistance against . We also emphasize that when choosing plant material for restoration, performance during both pulse (resource-rich) and inter-pulse (resource-poor) periods should be considered.

关键词： annual grass comparative growth drought response invasive plant native grass specific leaf area soil-water use

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钱学森创立知识密集型草产业的划时代贡献

李毓堂

《中国工程科学》 2002年第4卷第1期页码 15-22

摘要：

文章论述了钱学森提出创建知识密集型草产业的历史背景、科学内涵、理论意义、应用成果和在21世纪中国可持续发展战略中的重要作用，并根据钱老的主张，提出当前启动全国大规模草产业工程必须创新管理机制。

关键词：钱学森知识密集型草产业草业系统工程可持续发展战略

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Corrigendum to “Multidecadal Trends in Large-Scale Annual Mean SATa Based on CMIP5 Historical Simulations Corrigendum

Nan Xing,Jianping Li,Lanning Wang

《工程（英文）》 2017年第3卷第3期页码 428-428 doi: 10.1016/J.ENG.2017.03.015

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THE ROLE OF LONG-TERM EXPERIMENTS IN VALIDATING TRAIT-BASED APPROACHES TO ACHIEVING MULTIFUNCTIONALITY IN GRASSLANDS

《农业科学与工程前沿（英文）》 2022年第9卷第2期页码 187-196 doi: 10.15302/J-FASE-2021438

摘要：

Quantifying the relationships between plant functional traits and ecosystem services has been promoted as an approach to achieving multifunctional grassland systems that balance productivity with other regulating, supporting and cultural services. Establishing trade-offs and synergies between traits and services has largely relied on meta-analyses of studies from different systems and environments. This study demonstrated the value of focused studies of long-term experiments in grassland systems that measure traits and services in the same space and time to better understand the ecological constraints underlying these trade-offs and synergies. An analysis is presented that uses data from the Park Grass Experiment at Rothamsted Research on above-ground productivity, species richness and soil organic carbon stocks to quantify the relationships between these three outcomes and the power of variance in plant functional traits in explaining them. There was a trade-off between plots with high productivity, nitrogen inputs and soil organic carbon and plots with high species richness that was explained by a functional gradient of traits that are indicative of contrasting strategies of resource acquisition of resource conservation. Examples were identified of using functional traits to identify opportunities for mitigating these trade-offs and moving toward more multifunctional systems.

关键词： multifunctional grassland systems / Park Grass Experiment / soil organic carbon / ecosystem service

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Proposal of a probabilistic assessment of structural collapse concomitantly subject to earthquake and gas explosion

Gholamreza ABDOLLAHZADEH, Hadi FAGHIHMALEKI

《结构与土木工程前沿（英文）》 2018年第12卷第3期页码 425-437 doi: 10.1007/s11709-017-0427-5

摘要：

In recent decades, many public buildings, located in seismic-prone residential areas, had to grapple with abnormal loads against which the structures were unguarded. In this piece of research, an ordinary three dimensional reinforced concrete building is selected as case study. The building is located in an earthquake-prone region; however, it is designed according to seismic building codes. Yet, it is not shielded against abnormal loads, such as blasts. It is assumed that the building suffers a blast load, due to mechanical/thermal installation failure during or after intense seismic oscillations. These two critical incidents are regarded codependent and compatible. So the researchers developed scenarios and tried to assess different probabilities for each scenario and carried out an analysis to ensure if progressive collapse had set in or not. In the first step, two analysis models were used for each scenario; a non-linear dynamic time history analysis and a blast local dynamic analysis. In the second step, having the structural destructions of the first step in view, a pushdown analysis was carried out to determine the severity of progressive collapse and assess building robustness. Finally, the annual probability of structural collapse under simultaneous earthquake and blast loads was estimated and offered.

关键词： gas blast pushdown analysis progressive collapse annual probability of structural collapse 3D model of structure

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Potential of performance improvement of concentrated solar power plants by optimizing the parabolic trough receiver

Honglun YANG, Qiliang WANG, Jingyu CAO, Gang PEI, Jing LI

《能源前沿（英文）》 2020年第14卷第4期页码 867-881 doi: 10.1007/s11708-020-0707-y

摘要： This paper proposes a comprehensive thermodynamic and economic model to predict and compare the performance of concentrated solar power plants with traditional and novel receivers with different configurations involving operating temperatures and locations. The simulation results reveal that power plants with novel receivers exhibit a superior thermodynamic and economic performance compared with traditional receivers. The annual electricity productions of power plants with novel receivers in Phoenix, Sevilla, and Tuotuohe are 8.5%, 10.5%, and 14.4% higher than those with traditional receivers at the outlet temperature of 550°C. The levelized cost of electricity of power plants with double-selective-coated receivers can be decreased by 6.9%, 8.5%, and 11.6%. In Phoenix, the optimal operating temperature of the power plants is improved from 500°C to 560°C by employing a novel receiver. Furthermore, the sensitivity analysis of the receiver heat loss, solar absorption, and freeze protection temperature is also conducted to analyze the general rule of influence of the receiver performance on power plants performance. Solar absorption has a positive contribution to annual electricity productions, whereas heat loss and freeze protection temperature have a negative effect on electricity outputs. The results indicate that the novel receiver coupled with low melting temperature molten salt is the best configuration for improving the overall performance of the power plants.

关键词： concentrated solar power parabolic trough receiver heat loss solar energy annual performance

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兴建年产一千吨电子级多晶硅工厂的思考

梁骏吾

《中国工程科学》 2000年第2卷第6期页码 33-35

摘要：

文章简要评述了世界以及中国的电子级多晶硅的生产能力和市场需求。在2000年和2010年中国对多晶硅的需求分别是736 t/a和1304 t/a。但近几年中国的多晶硅生产仅达到80 t/a，所以在中国建设一座年产1000 t电子级多晶硅的工厂是很合理的。然而由最新统计数据可知，自1997年以来，世界多晶硅生产能力连年均超过市场需求，而且在最近的将来，这一趋势将会继续。为了占领国内多晶硅市场，未来的多晶硅工厂将面临挑战，产品质量和生产成本是应当考虑的最重要指标。为了占领国内市场，在保证多晶硅产品纯度的前提下，生产成本只能略微超过20美元/kg。

关键词：多晶硅半导体工业规模生产

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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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Determination of a suitable index for a solvent via two-column extractive distillation using a heuristic method

Zhaoyou Zhu, Guoxuan Li, Yao Dai, Peizhe Cui, Dongmei Xu, Yinglong Wang

《化学科学与工程前沿（英文）》 2020年第14卷第5期页码 824-833 doi: 10.1007/s11705-019-1867-3

摘要： The traditional approach to solvent selection in the extractive distillation process strictly focuses on the change in the relative volatility of light-heavy components induced by the solvent. However, the total annual cost of the process may not be minimal when the solvent induces the largest change in relative volatility. This work presents a heuristic method for selecting the optimal solvent to minimize the total annual cost. The functional relationship between the relative volatility and the total annual cost is established, where the main factors, such as the relative volatility of the light-heavy components and the relative volatility of the heavy-component solvent, are taken into account. Binary azeotropic mixtures of methanol-toluene and methanol-acetone are separated to verify the feasibility of the model. The results show that using the solvent with the minimal two-column extractive distillation index, the process achieves a minimal total annual cost. The method is conducive for sustainable advancements in chemistry and engineering because a suitable solvent can be selected without simulation verification.

关键词： heuristic method solvent selection extractive distillation total annual cost

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Probabilistic safety assessment of self-centering steel braced frame

Navid RAHGOZAR, Nima RAHGOZAR, Abdolreza S. MOGHADAM

《结构与土木工程前沿（英文）》 2018年第12卷第1期页码 163-182 doi: 10.1007/s11709-017-0384-z

摘要： The main drawback of conventional braced frames is implicitly accepting structural damage under the design earthquake load, which leads to considerable economic losses. Controlled rocking self-centering system as a modern low-damage system is capable of minimizing the drawbacks of conventional braced frames. This paper quantifies main limit states and investigates the seismic performance of self-centering braced frame using a Probabilistic Safety Assessment procedure. Margin of safety, confidence level, and mean annual frequency of the self-centering archetypes for their main limit states, including PT yield, fuse fracture, and global collapse, are established and are compared with their acceptance criteria. Considering incorporating aleatory and epistemic uncertainties, the efficiency of the system is examined. Results of the investigation indicate that the design of low- and mid-rise self-centering archetypes could provide the adequate margin of safety against exceeding the undesirable limit-states.

关键词： self-centering steel braced frame mean annual frequency safety assessment confidence level margin of safety

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Determining the optimum economic insulation thickness of double pipes buried in the soil for district heating systems

Fating LI, Pengfei JIE, Zhou FANG, Zhimei WEN

《能源前沿（英文）》 2021年第15卷第1期页码 170-185 doi: 10.1007/s11708-020-0680-5

摘要： The insulation thickness (IT) of double pipes buried in the soil (DPBIS) for district heating (DH) systems was optimized to minimize the annual total cost of DPBIS for DH systems. An optimization model to obtain the optimum insulation thickness (OIT) and minimum annual total cost (MATC) of DPBIS for DH systems was established. The zero point theorem and fsolve function were used to solve the optimization model. Three types of heat sources, four operating strategies, three kinds of insulation materials, three buried depth (BD) values, and seven nominal pipe size (NPS) values were considered in the calculation of the OIT and MATC of DPBIS for DH systems, respectively. The optimization results for the above factors were compared. The results show that the OIT and MATC of DPBIS for DH systems can be obtained by using the optimization model. Sensitivity analysis was conducted to investigate the impact of some economic parameters, i.e., unit heating cost, insulation material price, interest rate, and insulation material lifetime, on optimization results. It is found out that the impact of sensitivity factors on the OIT and MATC of DPBIS for DH systems is different.

关键词： double pipes optimization model optimum insulation thickness minimum annual total cost

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Potential sources of unintentionally produced PCB, HCB, and PeCBz in China: A preliminary overview

Xiaotu Liu, Heidelore Fiedler, Wenwen Gong, Bin Wang, Gang Yu

《环境科学与工程前沿（英文）》 2018年第12卷第6期 doi: 10.1007/s11783-018-1036-9

摘要：

A preliminary analysis of potential sources for unintentionally produced PCB, HCB and PeCBz in China.

Activity rates of sources for reference years from 2000 to 2015 provided.

Emissions from a number of sources summarized and compared.

Implications for future research and regulation discussed.

关键词： Unintentionally produced POPs Polychlorinated biphenyls Hexachlorobenzene Pentachlorobenzene sources of releases Annual production activities

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把我国广大的沙化草原建设成为可再生的世界级特大的清洁能源生产基地

严隽森

《中国工程科学》 2010年第12卷第3期页码 22-29

摘要：

中国有广大的约占国土面积40 %的沙化退化草原，不宜亦没有用作粮食耕地。但经过大力的生态建设后每年能产出巨量的巨银草。后者是原生在中国北部，能耐干寒和恶劣环境，并是多年生高达3.5 m的巨大稠密的野草，并能利用咸水。将这些巨银草气化催化后估计每公顷可产出17.2 t的可直接替代汽油的生物丁醇，生化和基因研发专业公司孟山都和孟代尔等己开始合力提升此产能，估计到2030年左右，以沙化草原的约46 %的面积种植巨量的巨银草，可使中国开始不再依赖石油和煤炭的化石能源，而转用由巨大的“巨银草油田群”供应的可再生的清洁能源，其余的面积的产量可供外销或作他用，使中国能长期成为世界能源强国，与他国合力稳定能源供应和价格，并引领世界迈向可再生的清洁能源新时代。

关键词：沙化草原巨银草可再生清洁能源丁醇

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我国村镇规划建设管理的问题与对策

曹璐,谭静,魏来,卓佳,华传哲,蒋鸣,冯旭

《中国工程科学》 2019年第21卷第2期页码 14-20 doi: 10.15302/J-SSCAE-2019.02.012

摘要：

“村镇规划建设与管理”课题组通过对我国多个省份的大量调研，总结归纳了三大问题：村镇规划指导思想、方式方法与内容不适应新型城乡关系构建与农村发展要求；规划管理体制与管理模式不符合乡村基层治理体系特征与建设管控现实；土地的供给模式与利用格局不满足土地合理利用的总体目标和乡村建设发展的实际需求。同时，结合国内相关创新实践经验和发展趋势预判，提出完善法律法规，推进村镇规划、建设、运营和管理的系统化与法制化；以县为单位统筹构建乡村规划编制体系；以村镇规划统筹村镇各类建设行为；以乡村治理有效为基础，创新规划编制与管理方式；以新技术手段支持村镇规划编制与管理等政策建议。

关键词：规划管理体制乡村基层治理体系土地供给模式创新规划编制与管理方式