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The numerical analysis of thermal effect and weld shaping of DE-GMAW under composite heat source

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China Welding 2016年第2期25卷 6-13页

作者： Huang Jiankang du wenyu Shi Yu Han Rihong Fan Ding State Key Laboratory of Gansu Advanced Nonferrous Metal Materials Lanzhou University of Technology Lanzhou 73005

The action of the composite heat source model in DE-GMAW has been carried out according to the characteristics of the DE-GMA W process, and the distribution of surface and body heat source was analyzed. The weld temperature field distribution has been derived from the appropriate boundary conditions and the thermal physical property parameters by COMSOL software. The effects of the positions of the surface and body heat source on the cross- sectional shape were investigated by studying the experimental welding thermal cycle curve. The simulated results are fully compliant with the experimental data under the same conditions. This illustrates that the composite heat source model is correct. It reflects the thermal mechanism of DE-GMA W process, and reveals the internal influence of weld shaping.

关键词： double electrode-gas metal arc welding composite heat source weld shaping numerical analysis

基于HS-SPME-GC-MS的不同成熟度‘青皮’无花果挥发性成分分析

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中国果菜 2024年第4期44卷 14-19页

作者：刘雪梅闫新焕谭梦男谷思梦杜文瑜许敏宋烨中华全国供销合作总社济南果品研究所山东济南250220

为探讨不同成熟度威海‘青皮’无花果挥发性成分差异,本研究采用固相微萃取(SPME)和气相色谱-质谱联用技术(GC-MS)对鲜食无花果挥发性成分进行分析,并采用内标法对风味物质进行定量分析。结果显示,在威海‘青皮’无花果中共检测出73种... 详细信息

为探讨不同成熟度威海‘青皮’无花果挥发性成分差异,本研究采用固相微萃取(SPME)和气相色谱-质谱联用技术(GC-MS)对鲜食无花果挥发性成分进行分析,并采用内标法对风味物质进行定量分析。结果显示,在威海‘青皮’无花果中共检测出73种挥发性成分,主要为酯类、醛类、醇类、烯类、烷烃类等,其中六成熟无花果检出33种、八成熟检出29种、十成熟检出36种。不同成熟度无花果的挥发性组分、特征风味物质种类和含量差异明显。

关键词：无花果挥发性成分气相色谱-质谱联用技术固相微萃取

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Pixelated non-volatile programmable photonic integrated circuits with 20-level intermediate states

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International Journal of Extreme Manufacturing 2024年第3期6卷 477-487页

作者： wenyu Chen Shiyuan Liu Jinlong Zhu State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074People’s Republic of China Optics Valley Laboratory WuhanHubei 430074People’s Republic of China

Multi-level programmable photonic integrated circuits(PICs)and optical metasurfaces have gained widespread attention in many fields,such as neuromorphic photonics,opticalcommunications,and quantum *** this paper,we propose pixelated programmable Si_(3)N_(4)PICs with record-high 20-level intermediate states at 785 nm *** flexibility in phase or amplitude modulation is achieved by a programmable Sb_(2)S_(3)matrix,the footprint of whose elements can be as small as 1.2μm,limited only by the optical diffraction limit of anin-house developed pulsed laser writing *** believe our work lays the foundation for laser-writing ultra-high-level(20 levels and even more)programmable photonic systems and metasurfaces based on phase change materials,which could catalyze diverse applications such as programmable neuromorphic photonics,biosensing,optical computing,photonic quantum computing,and reconfigurable metasurfaces.

关键词： programmable photonic integrated circuits phase change materials multi-level intermediate states metasurfaces

Grassland-type ecosystem stability in China differs under the influence of drought and wet events

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Journal of Arid Land 2024年第5期16卷 615-631页

作者： CAO wenyu BAI Jianjun YU Leshan School of Geography and Tourism Shaanxi Normal UniversityXi'an 710119China International Business School Shaanxi Normal UniversityXi'an 710119China

Ecological stability is a core issue in ecological research and holds significant implications forhumanity. The increased frequency and intensity of drought and wet climate events resulting from climatechange pose a major threat to global ecological stability. Variations in stability among different ecosystemshave been confirmed, but it remains unclear whether there are differences in stability within the sameterrestrial vegetation ecosystem under the influence of climate events in different directions and ***'s grassland ecosystem includes most grassland types and is a good choice for studying this *** study used the Standardized Precipitation Evapotranspiration Index-12 (SPEI-12) to identify thedirections and intensities of different types of climate events, and based on Normalized DifferenceVegetation Index (NDVI), calculated the resistance and resilience of different grassland types for 30consecutive years from 1990 to 2019 (resistance and resilience are important indicators to measurestability). Based on a traditional regression model, standardized methods were integrated to analyze theimpacts of the intensity and duration of drought and wet events on vegetation stability. The resultsshowed that meadow steppe exhibited the highest stability, while alpine steppe and desert steppe had thelowest overall stability. The stability of typical steppe, alpine meadow, temperate meadow was at anintermediate level. Regarding the impact of the duration and intensity of climate events on vegetationecosystem stability for the same grassland type, the resilience of desert steppe during drought was mainlyaffected by the duration. In contrast, the impact of intensity was not significant. However, alpine steppewas mainly affected by intensity in wet environments, and duration had no significant impact. Ourconclusions can provide decision support for the future grassland ecosystem governance.

关键词： grassland ecosystem stability resistance resilience different climate types drought climate event wet climate event

Soybean maize strip intercropping:A solution for maintaining food security in China

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Journal of Integrative Agriculture 2024年第7期23卷 2503-2506页

作者： Jiang Liu wenyu Yang Sichuan Engineering Research Center for Crop Strip Intercropping System/Key Laboratory of Crop Ecophysiology and Farming System in Southwest Ministry of Agriculture and Rural AffairsChengdu 611130China College of Life Science Sichuan Agricultural UniversityYa’an 625014China State Key Laboratory of Crop Gene Exploration and Utilization in Southwest China Chengdu 611130China

The practice of intercropping leguminous and gramineous crops is used for promoting sustainable agriculture,optimizing resource utilization,enhancing biodiversity,and reducing reliance on petroleum ***,promoting conventional intercropping strategies in modern agriculture can prove *** innovative technology of soybean maize strip intercropping(SMSI)has been proposed as a *** system has produced remarkable results in improving domestic soybean and maize production for both food security and sustainable *** this article,we provide an overview of SMSI and explain how it differs from traditional *** also discuss the core principles that foster higher yields and the prospects for its future development.

关键词： strip intercropping food security soybean maize spatial arrangement

Identification of rural courtyards’utilization status using deep learning and machine learning methods on unmanned aerial vehicle images in north China

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Building Simulation 2024年第5期17卷 799-818页

作者： Maojun Wang wenyu Xu Guangzhong Cao Tao Liu College of Resource Environment and Tourism Capital Normal UniversityBeijing 100048China College of Urban and Environmental Sciences Peking UniversityBeijing 100871China

The issue of unoccupied or abandoned homesteads(courtyards)in China emerges given the increasing aging population,rapid urbanization and massive rural-urban *** the aspect of rural vitalization,land-use planning,and policy making,determining the number of unoccupied courtyards is *** and questionnaire-based surveys were currently the main approaches,but these traditional methods were often expensive and laborious.A new workflow is explored using deep learning and machine learning algorithms on unmanned aerial vehicle(UAV)***,features of the built environment were extracted using deep learning to evaluate the courtyard management,including extracting complete or collapsed farmhouses by Alexnet,detecting solar water heaters by YOLOv5s,calculating green looking ratio(GLR)by *** precisions exceeded 98%.Then,seven machine learning algorithms(Adaboost,binomial logistic regression,neural network,random forest,support vector machine,decision trees,and XGBoost algorithms)were applied to identify the rural courtyards’utilization *** Adaboost algorithm showed the best performance with the comprehensive consideration of most metrics(Accuracy:0.933,Precision:0.932,Recall:0.984,F1-score:0.957).Results showed that identifying the courtyards’utilization statuses based on the courtyard built environment is *** is transferable and cost-effective for large-scale village surveys,and may contribute to the intensive and sustainable approach to rural land use.

关键词： unoccupied homesteads courtyard built environment inner courtyard management GLR solar water heaters machine learning algorithms

Coordinated responses of leaf and nodule traits contribute to the accumulation of N in relay intercropped soybean

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Journal of Integrative Agriculture 2024年第6期23卷 1910-1928页

作者： Ping Chen Qing du Benchuan Zheng Huan Yang Zhidan Fu Kai Luo Ping Lin Yilin Li Tian Pu Taiwen Yong wenyu Yang College of Agronomy Sichuan Agricultural University/Sichuan Engineering Research Center for Crop Strip Intercropping System/Key Laboratory of Crop Ecophysiology and Farming System in SouthwestMinistry of Agriculture and Rural AffairsChengdu 611130China Crop Research Institute Sichuan Academy of Agricultural SciencesChengdu 610066China

Maize(Zea mays L.)-soybean(Glycine max ***.)relay intercropping provides a way to enhance land ***,the late-planted soybean suffers from shading by the *** maize harvest,how the recovery growth influences the leaf and nodule traits remains unclear.A three-year field experiment was conducted to evaluate the effects of genotypes,i.e.,supernodulating(nts1007),Nandou 12(ND12),and Guixia 3(GX3),and crop configurations,i.e.,the interspecific row spacing of 45(I45),60(I60),75 cm(I75),and sole soybean(SS),on soybean recovery growth and N *** results showed that intercropping reduced the soybean total leaf area(LA)by reducing both the leaf number(LN)and unit leaflet area(LUA),and it reduced the nodule dry weight(NW)by reducing both the nodule number(NN)and nodule diameter(ND)compared with the *** correlation and principal component analysis(PCA)indicated a co-variability of the leaf and nodule traits in response to the genotype and crop configuration *** the recovery growth stages,the compensatory growth promoted soybean growth to reduce the gaps of leaf and nodule traits between intercropping and *** relative growth rates of ureide(RGR_U)and nitrogen(RGR_N)accumulation were higher in intercropping than in *** achieved more significant sucrose and starch contents compared with ***12 and GX3 showed more robust compensatory growth than nts1007 in *** the recovery growth of relay intercropping soybean improved biomass and nitrogen accumulation,ND12 gained a more significant partial land equivalent ratio(pLER)than *** I60 treatment achieved more robust compensation effects on biomass and N accumulation than the other ***,I60 showed a higher nodule sucrose content and greater shoot ureide and N accumulation than ***,intercropping ND12 with maize using an interspecific row spacing of 60 cm was optimal for both yield advantage and N accumulation.

关键词： relay intercropping genotype crop configuration symbiotic nitrogen fixation soybean nodule

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唐长安大明宫建筑丛考

中国历史地理论丛 2014年第3期29卷 102-111页

作者：杜文玉陕西师范大学历史文化学院陕西西安710062

唐长安大明宫的建筑布局,自宋代以来历代学者多有研究,然未尽之处仍然颇多,如关于御史北台、待制院、舍人院、京兆尹院、灵符应圣院以及左、右藏库等机构在宫中的方位与职能,或未涉及,或有错误。本文主要针对以上建筑物在宫中的地理方... 详细信息

唐长安大明宫的建筑布局,自宋代以来历代学者多有研究,然未尽之处仍然颇多,如关于御史北台、待制院、舍人院、京兆尹院、灵符应圣院以及左、右藏库等机构在宫中的方位与职能,或未涉及,或有错误。本文主要针对以上建筑物在宫中的地理方位与职能,进行考述,希望能恢复历史的本来面貌。

关键词：大明宫御史北台待制院舍人院京兆尹院灵符应圣院左右藏库

论唐宋监狱中的医疗系统——兼论病囚院的设置

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江汉论坛 2007年第5期 90-97页

作者：杜文玉陕西师范大学历史文化学院教授西安710062

给狱中的病囚医治病患早在汉代就已经实施了,但是比较完善详尽的制度却出现在唐代,至五代时期遂出现了专门针对病囚的医疗机构——病囚院,两宋时期沿袭五代之制,使这一制度更加完善。唐宋时期这一制度的主要特点是:病囚医疗费用由官府负... 详细信息

给狱中的病囚医治病患早在汉代就已经实施了,但是比较完善详尽的制度却出现在唐代,至五代时期遂出现了专门针对病囚的医疗机构——病囚院,两宋时期沿袭五代之制,使这一制度更加完善。唐宋时期这一制度的主要特点是:病囚医疗费用由官府负责,非重罪病囚允许家人入侍,宋代甚至规定轻罪病囚可以保外就医,病囚必须脱去枷锁等刑具并免服苦役,对病囚讯问不许用刑等,在预防疾病方面也制定了严格的规定。唐宋时期的这一制度对后世产生了较大的影响。

关键词：病囚狱医病囚院监狱制度洒扫牢狱