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MODIFIED GENETIC ALGORITHM APPLIED TO SOLVE PRODUCT FAMILY OPTIMIZATION PROBLEM

Chinese Journal of Mechanical Engineering 2007年第4期20卷 106-111页

作者： chen chunbao wang liya Department of Industrial Engineering and Management Shanghai Jiaotong University Shanghai 200030 China

The product family design problem solved by evolutionary algorithms is discussed. A successful product family design method should achieve an optimal tradeoff among a set of competing objectives, which involves maximizing commonality across the family of products and optimizing the performances of each product in the family. A 2-level chromosome structured genetic algorithm （2LCGA） is proposed to solve this class of problems and its performance is analyzed in comparing its results with those obtained with other methods. By interpreting the chromosome as a 2-level linear structure, the variable commonality genetic algorithm （GA） is constructed to vary the amount of platform commonality and automatically searches across varying levels of commonality for the platform while trying to resolve the tradeoff between commonality and individual product performance within the product family during optimization process. By incorporating a commonality assessing index to the problem formulation, the 2LCGA optimize the product platform and its corresponding family of products in a single stage, which can yield improvements in the overall performance of the product family compared with two-stage approaches （the first stage involves determining the best settings for the platform variables and values of unique variables are found for each product in the second stage）. The scope of the algorithm is also expanded by introducing a classification mechanism to allow mul- tiple platforms to be considered during product family optimization, offering opportunities for superior overall design by more efficacious tradeoffs between commonality and performance. The effectiveness of 2LCGA is demonstrated through the design of a family of universal electric motors and comparison against previous results.

关键词： Product family design Product platform Genetic algorithm Optimization

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Energy Conversion Efficiency of Rainbow Shape Piezoelectric Transducer

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Chinese Journal of Aeronautics 2012年第5期25卷 691-697页

作者： LIU Xiangjian chen Renwen ZHU liya Aeronautical Science Key Laboratory for Smart Materials and Structures Nanjing University of Aeronautics and AstronauticsNanjing 210016China

With the aim to enhance the energy conversion efficiency of the rainbow shape piezoelectric transducer, an analysis model of energy conversion efficiency is established based on the elastic mechanics theory and piezoelectricity theory. It can be found that the energy conversion efficiency of the rainbow shape piezoelectric transducer mainly depends on its shape parameters and ma- terial properties from the analysis model. Simulation results show that there is an optimal length ratio to generate maximum en- ergy conversion efficiency and the optimal length ratios and energy conversion efficiencies of beryllium bronze substrate trans- ducer and steel substrate transducer are （0.65, 2.21%） and （0.65, 1.64%） respectively. The optimal thickness ratios and energy conversion efficieneies of beryllium bronze substrate transducer and steel substrate transducer are （1.16, 2.56%） and （1.49, 1.57%） respectively. With the increase of width ratio and initial curvature radius, both the energy conversion efficiencies de- crease. Moreover, beryllium bronze flexible substrate transducer is superior to the steel flexible substrate transducer.

关键词： energy conversion efficiency rainbow shape piezoelectric transducer theoretical analysis energy harvesting elec-tromechanical coupling coefficient

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(Ho_(0.25)Lu_(0.25)Yb_(0.25)Eu_(0.25))_(2)SiO_(5) high-entropy ceramic with low thermal conductivity,tunable thermal expansion coefficient,and excellent resistance to CMAS corrosion

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Journal of Advanced Ceramics 2022年第8期11卷 1279-1293页

作者： Zhilin chen Zhilin TIAN liya ZHENG Keyu MING Xiaomin REN Jingyang wang Bin LI School of Materials Shenzhen Campus of Sun Yat-sen UniversityShenzhen 518107China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Materials Science and Engineering University of Science and Technology of ChinaHefei 230026China

Low thermal conductivity,compatible thermal expansion coefficient,and good calcium–magnesium–aluminosilicate(CMAS)corrosion resistance are critical requirements of environmental barrier coatings for silicon-based *** earth silicates have been recognized as one of the most promising environmental barrier coating candidates for good water vapor corrosion ***,the relatively high thermal conductivity and high thermal expansion coefficient limit the practical *** by the high entropy effect,a novel rare earth monosilicate solid solution(Ho_(0.25)Lu_(0.25)Yb_(0.25)Eu_(0.25))_(2)SiO_(5)was designed to improve the overall *** as-synthesized(Ho_(0.25)Lu_(0.25)Yb_(0.25)Eu_(0.25))_(2)SiO_(5)shows very low thermal conductivity(1.07 W·m-1·K-1 at 600℃).Point defects including mass mismatch and oxygen vacancies mainly contribute to the good thermal insulation *** thermal expansion coefficient of(Ho_(0.25)Lu_(0.25)Yb_(0.25)Eu_(0.25))_(2)SiO_(5)can be decreased to(4.0–5.9)×10^(-6)K^(-1)due to severe lattice distortion and chemical bonding variation,which matches well with that of SiC((4.5–5.5)×10^(-6)K^(-1)).In addition,(Ho_(0.25)Lu_(0.25)Yb_(0.25)Eu_(0.25))_(2)SiO_(5)presents good resistance to CMAS *** improved performance of(Ho_(0.25)Lu_(0.25)Yb_(0.25)Eu_(0.25))_(2)SiO_(5)highlights it as a promising environmental barrier coating candidate.

关键词： high-entropy ceramic environmental barrier coating(EBC) rare earth silicate thermal conductivity thermal expansion coefficient(TEC)

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A climatological northern boundary index for the East Asian summer monsoon and its interannual variability

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Science China Earth Sciences 2018年第1期61卷 13-22页

作者： chen Jie HUANG Wei JIN liya chen JianHui chen ShengQian chen FaHu Key Laboratory of Western China's Environmental Systems (Ministry of Education) College of Earth and Environmental Sciences Lanzhou University School of Atmospheric Sciences Chengdu University of Information Technology Key Laboratory of Alpine Ecology and Biodiversity (LAEB) Tibetan Plateau Earth Sciences of the Chinese Academy of Sciences

A long-term perspective on the spatial variation of the northern boundary of the East Asian summer monsoon(EASM) and the related physical mechanisms is important for understanding past climate change in Asia and for predicting future changes. However, most of the meteorological definitions of the EASM northern boundary do not correspond well to the actual geographical environment, which is problematic for paleoclimatic research. Here, we use monthly CMAP and GPCP precipitation data to define a new EASM northern boundary index by using the concept of the global monsoon, which is readily applicable to paleoclimatic research. The results show that the distribution of the 2 mm day^(-1) precipitation isoline(i.e., 300 mm precipitation)has a good relationship with the spatial distribution of modern land cover types, the transitional climate zone and the potential natural vegetation types, in China. The locations of the precipitation isolines also correspond well to the locations of major shifts in wind direction. These results suggest that the 2 mm day^(-1) isoline has a clear physical significance since the climatic, ecological,and geographical boundary can be used as the northern boundary index of the EASM(which we call the climatological northern boundary index). The index depicts the northeast-southwest orientation of the climatological(1981-2010) EASM northern boundary, along the eastern part of the Qilian Mountains-southern foothills of the Helan Mountains-Daqing Mountains-western margin of the Greater Khingan Range, from west to east across Northwest and Northeast China. The interannual change of the EASM northern boundary from 1980 to 2015 covers the central part of Gansu, the northern part of Ningxia, the eastern part of Inner Mongolia and the northeastern region in China. It can extend northward to the border between China and Mongolia and retreat southward to Shangdong-central Henan. There is a 200-700 km fluctuation range of the interannual EASM northern bound

关键词： East Asian summer monsoon Climatological northern boundary index Interannual change Spatial fluctuations

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Preparation and Control of the Formation of Single Core and Clustered Nanoparticles for Biomedical Applications Using a Versatile Amphiphilic Diblock Copolymer

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Nano Research 2010年第12期3卷 852-862页

作者： Hongwei chen Julie Yeh liya wang Hafsa Khurshid Nan Peng Andrew Ywang Hui Mao Department of Radiology Center for Systems ImagingEmory University School of MedicineAtlantaGeorgia 30322USA Department of Physics and Astronomy University of DelawareNewarkDelaware 19716USA Department of Rehabilitation Medicine Chinese PLA General Hospital28 Fuxing RoadBeijing 100853China Ocean NanoTech LLC2143 Worth LaneSpringdaleArkansas 72764USA

We report the application of a versatile diblock copolymer,poly(ethylene oxide)-b-poly(γ-methacryloxypropyl trimethoxysilane)(PEO-b-PγMPS),to prepare nanocrystals such as iron oxide nanoparticles or quantum dots,with either a single core or multi-core cluster,for biomedical *** amphiphilic copolymer comprises both a hydrophilic PEO segment and a hydrophobic segment with a“surface anchoring moiety”(the silane group)which can interact effectively with the hydrophobic nanocrystals through ligand *** of the unique features of this work is that we can control the formation of either single core nanoparticles or multi-core nanoclusters by simply varying the conditions of ligand exchange and aging of the mixture of block copolymer and nanoparticles without needing to change the *** morphologies of the resulting single core nanoparticles or multi-core nanoclusters were confirmed by dynamic light scattering and transmission electron *** clustered nanoparticles exhibit enhanced physicochemical properties that are beyond those expected from a simple accumulation of individual ***,the hybrid nanoparticles containing both magnetic iron oxide nanoparticles and optical quantum dots obtained using our strategy provide have combined magnetic and optical functionalities that allow for potential new and expanded biomedical applications,as demonstrated by their use for magnetic resonance imaging and biomarker-targeted cell imaging.

关键词： Magnetic nanoparticles quantum dots nanoparticle coating copolymer multifunctional nanoparticles imaging

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Strengthened Indian summer monsoon brought more rainfall to the western Tibetan Plateau during the early Holocene

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Science Bulletin 2019年第20期64卷 1482-1485页

作者： Xiangjun Liu Xiaojian Zhang Yanluan Lin liya Jin Fahu chen College of Geography and Environmental Science Northwest Normal UniversityLanzhou730070China Center for Excellence in Tibetan Plateau Earth Sciences Chinese Academy of SciencesBeijing100101China School of Geography and Ocean Science Nanjing UniversityNanjing210023China Ministry of Education Key Laboratory for Earth System Modeling Department of Earth System Scienceand Joint Center for Global Change StudiesTsinghua UniversityBeijing100084China School of Atmoshpheric Sciences Chengdu University of Information TechnologyChengdu610225China CAS Key Laboratory of Alpine Ecology Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing100101China

The Tibetan Plateau(TP)is considered to be the‘‘Third Pole”of the earth because of its huge area(5 million km2),its high elevation(>4000 m average altitude),and the presence of more than 100,000 km2 of glaciers in this northern mid-latitude *** a result of these factors,the TP influences both short-term regional and large-scale atmospheric circulation and long-term climate change[1].More than ten large rivers originate from the TP and constitute an essential water supply for nearly one sixth of the global *** the TP is often referred to as‘‘the water tower of Asia”[1,2].Variations of summer rainfall over the TP greatly impact inland closed lakes,river discharge,glaciers,plant phenology,and natural hazards[2].

关键词： China Strengthened Indian summer monsoon brought more rainfall to the western Tibetan Plateau during the early Holocene western

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Spatiotemporal precipitation variations in the arid Central Asia in the context of global warming

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Science China Earth Sciences 2011年第11期54卷 1812-1821页

作者： chen FaHu HUANG Wei JIN liya chen JianHui wang JinSong MOE Key Laboratory of West China＇s Environmental System Lanzhou University Lanzhou 730000 China Key Open Laboratory of Arid Climate Change and Disaster Reduction China Meteorological Administration Lanzhou 730020 China

This study analyzed the temporal precipitation variations in the arid Central Asia （ACA） and their regional differences during 1930-2009 using monthly gridded precipitation from the Climatic Research Unit （CRU）. Our results showed that the annual precipitation in this westerly circulation dominated arid region is generally increasing during the past 80 years, with an apparent increasing trend （0.7 mm/10 a） in winter. The precipitation variations in ACA also differ regionally, which can be divided into five distinct subregions （Ⅰ West Kazakhstan region, Ⅱ East Kazakhstan region, ⅢCentral Asia Plains region, Ⅳ Kyrgyzstan region, and V Iran Plateau region）. The annual precipitation falls fairly even on all seasons in the two northern subregions （regions Ⅰ and Ⅱ, approximately north of 45°N）, whereas the annual precipitation is falling mainly on winter and spring （accounting for up to 80% of the annual total precipitation） in the three southern subregions. The annual precipitation is increasing on all subregions except the southwestern ACA （subregion Ⅴ） during the past 80 years. A significant increase in precipitation appeared in subregions Ⅰ and Ⅲ. The long-term trends in annual precipitation in all subregions are determined mainly by trends in winter precipitation. Additionally, the precipitation in ACA has significant interannual variations. The 2-3-year cycle is identified in all subregions, while the 5-6-year cycle is also found in the three southern subregions. Besides the inter-annual variations, there were 3-4 episodic precipitation variations in all subregions, with the latest episodic change that started in the mid- to late 1970s. The precipitations in most of the study regions are fast increasing since the late 1970s. Overall, the responses of ACA precipitation to global warming are complicated. The variations of westerly circulation are likely the major factors that influence the precipitation variations in the study region.

关键词： arid Central Asia annual and seasonal precipitation changing tendency regional difference

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Detecting the spatial-temporal pattern of moisture evolution on the Tibetan Plateau during the Holocene by model-proxy comparison

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Frontiers of Earth Science 2023年第4期17卷 981-996页

作者： Zeyu ZHENG liya JIN Jinjian LI Xiaojian ZHANG Jie chen MOE Key Laboratory of Western China’s Environmental System College of Earth and Environmental SciencesLanzhou UniversityLanzhou 730000China School of Atmospheric Sciences Chengdu University of Information TechnologyChengdu 610225China School of Geographic and Oceanographic Sciences Nanjing UniversityNanjing 210023China

The Tibetan Plateau(TP)is a key region for environmental and climatic research due to its significant linkages with large-scale atmospheric *** the long-term moisture evolution pattern and its forcing mechanisms on the TP during the Holocene may provide insights into the interaction between low-latitude climate systems and midlatitude ***,we synthesized 27 paleoclimate proxy records covering the past 9500 *** results of the rotated empirical orthogonal function analysis of the moisture variation revealed spatial-temporal heterogeneity,which was classified into 5 *** records were then compared with the results from the Kiel Climate Model and other *** results showed that moisture evolution on the western-southern-central TP was controlled by the Indian summer monsoon(ISM).On the south-eastern TP,moisture change was affected by the interplay between the East Asian summer monsoon(EASM)and the westerlies,as well as the *** diverse patterns of circulation system precipitation,moisture changes recorded in the paleorecords showed spatial-temporal discrepancies,especially during the early to middle ***,given the anti-phase pattern of summer precipitation in the EASM area under El Nino/Southern Oscillation(ENSO)conditions and the unstable relationship between the ISM and ENSO,it is reasonable to conclude that relatively strong ENSO variability during the late Holocene has contributed to these discrepancies as Asian summer monsoon precipitation has declined.

关键词： Tibetan Plateau Holocene moisture evolution model-proxy comparison

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Intrinsic chemiluminescence production from the degradation of haloaromatic pollutants during environmentally-friendly advanced oxidation processes:Mechanism,structure-activity relationship and potential applications

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Journal of Environmental Sciences 2017年第12期29卷 68-83页

作者： Benzhan Zhu chen Shen Huiying Gao liya Zhu Jie Shao Li Mao State Key Laboratory of Environmental Chemistry and Ecotoxicology Research Center for Eco-Environmental Sciences and University of Chinese Academy of SciencesChinese Academy of SciencesBeijing 100085China

The ubiquitous distribution of halogenated aromatic compounds（XAr） coupled with their carcinogenicity has raised public concerns on their potential risks to both human health and the ecosystem. Recently, advanced oxidation processes（AOPs） have been considered as an＂environmentally-friendly＂ technology for the remediation and destruction of such recalcitrant and highly toxic XAr. During our study on the mechanism of metal-independent production of hydroxyl radicals（UOH） by halogenated quinones and H_2O_2, we found, unexpectedly, that an unprecedented UOH-dependent two-step intrinsic chemiluminescene（CL） can be produced by H_2O_2 and tetrachloro-p-benzoquinone, the major carcinogenic metabolite of the widely used wood preservative pentachlorophenol. Further investigations showed that, in all UOH-generating systems, CL can also be produced not only by pentachlorophenol and all other halogenated phenols, but also by all XAr tested. A systematic structure–activity relationship study for all 19 chlorophenolic congeners showed that the CL increased with an increasing number of Cl-substitution in general. More importantly, a relatively good correlation was observed between the formation of quinoid/semiquinone radical intermediates and CL generation. Based on these results, we propose that UOH-dependent formation of quinoid intermediates and electronically excited carbonyl species is responsible for this unusual CL production; and a rapid, sensitive,simple, and effective CL method was developed not only to detect and quantify trace amount of XAr, but also to provide useful information for predicting the toxicity or monitoring real-time degradation kinetics of XAr. These findings may have broad chemical, environmental and biological implications for future studies on halogenated aromatic persistent organic pollutants.

关键词： Halogenated phenols Halogenated quinoid intermediates Semiquinone radical Hydroxyl radicals Fenton reaction Chemiluminescene method

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Suppressing the phase transition of ZrP_(2)O_(7), by defect and entropy regulation for high-temperature wave-transparent material application

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Journal of Advanced Ceramics 2024年第8期13卷 1164-1177页

作者： Peng Liu Zhilin Tian Zhilin chen Shuping Wen liya Zheng Bin Li School of Materials Shenzhen Campus of Sun Yat-sen UniversityShenzhen 518107China

ZrP_(2)O_(7) is a promising wave-transparent material due to its low dielectric constant and low dielectric loss,but its inherent phase transition characteristic at approximately 300℃ limits its high-temperature ***,suppressing the phase transition is necessary for ZrP_(2)O_(7),to serve in extremely harsh *** this work,introducing Ti and Hf into ZrP_(2)O_(7) causes significant lattice distortion and an increase in entropy,both of which synergistically limit the crystal structure *** addition,enhanced phonon scattering by mismatch of atomic mass and local distortion leads to a reduction in the thermal *** distortions also cause changes in both bond length and tilting angle,so that(Ti_(1/3)Zr_(1/3)Hf_(1/3))P_(2)O_(7) does not undergo sudden expansion as does ZrP_(2)O_(7).(Ti_(1/3)Zr_(1/3)Hf_(1/3))ZrP_(2)O_(7) maintains excellent dielectric properties,which highlights it as a promising high-temperature wave-transparent material.

关键词： wave-transparent material medium-entropy ceramics phase transition dielectric constant thermal expansion thermal conductivity

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