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Experimental study and simulation on the creep characteristics of machineharvested seed cotton

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International Journal of Agricultural and Biological Engineering 2024年第1期17卷 241-250页

作者： Ximei Wei Hongwen Zhang Jun wang shufeng Li Lei wang Xintian Du College of Mechanical and Electrical Engineering Shihezi UniversityShihezi 832003XinjiangChina Key Laboratory of Northwest Agricultural Equipment Ministry of AgricultureShihezi 832003XinjiangChina

In view of the unclear understanding of the basic scientific problems such as the rheological mechanism of seed cotton,especially the lack of research on the creep characteristics of seed cotton,the machine-harvested seed cotton in the Xinjiang region was taken as the research object to find out the compression creep characteristics.The universal material testing machine was used to carry out a one-factor creep test,taking moisture content,feed quality,compression times,and trash content as test factors and instantaneous elastic modulus,hysteretic elastic modulus,viscosity coefficient,and delay time as test indicators.The ANOVA and correlation were analyzed by SPSS,and the creep process of the seed cotton was simulated by ADAMS.Results show that moisture content significantly affects the instantaneous elastic modulus,hysteretic elastic modulus,and viscosity coefficient(p<0.01).In addition,each value of which decreases with the increase in moisture content.Feed quality significantly affects the hysteretic elastic modulus and viscosity coefficient(p<0.05).Moreover,the hysteretic elastic modulus and viscosity coefficient increase with the increase in feed quality.The compression times significantly influence the instantaneous elastic modulus,hysteretic elastic modulus,and viscosity coefficient(p<0.01),each value of which increases with the increase of compression times.Furthermore,the trash content significantly influenced the hysteretic elastic modulus and viscosity coefficient(p<0.05).The absolute error between the simulated and experimental values ek is within−0.011-0.030 mm,and the relative errorφk is less than 7%.The experimental results can provide theoretical and data support for the study of rheological characteristics of machine-harvested seed cotton,the design of seed cotton packing devices,and the molding quality of cotton bale(mold).

关键词： creep characteristics machine-harvested seed cotton analysis of ANOVA one-factor tests ADAMS

Competitive oxidation behavior of Ni-based superalloy GH4738 at extreme temperature

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International Journal of Minerals,Metallurgy and Materials 2024年第1期31卷 138-145页

作者： Hui Xu shufeng Yang Enhui wang Yunsong Liu Chunyu Guo Xinmei Hou Yanling Zhang State Key Laboratory of Advanced Metallurgy University of Science and Technology BeijingBeijing 100083China Institute for carbon neutrality University of Science and Technology BeijingBeijing 100083China

A high thrust-to-weight ratio poses challenges to the high-temperature performance of Ni-based superalloys. The oxidation behavior of GH4738 at extreme temperatures has been investigated by isothermal and non-isothermal experiments. As a result of the competitive diffusion of alloying elements, the oxide scale included an outermost porous oxide layer (OOL), an inner relatively dense oxide layer (IOL), and an internal oxide zone (IOZ), depending on the temperature and time. A high temperature led to the formation of large voids at the IOL/IOZ interface. At 1200℃, the continuity of the Cr-rich oxide layer in the IOL was destroyed, and thus, spallation occurred. Extension of oxidation time contributed to the size of Al-rich oxide particles with the increase in the IOZ. Based on this finding,the oxidation kinetics of GH4738 was discussed, and the corresponding oxidation behavior at 900-1100℃ was predicted.

关键词： Ni-based superalloy GH4738 extreme temperature competitive oxidation oxidation mechanism oxidation kinetics

Mechanism of nitrogen loss driven by soil and water erosion in water source areas

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林业研究:英文版 2023年第6期34卷 1985-1995页

作者： Rongjia wang Jianfeng Zhang Chunju Cai shufeng wang State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityHangzhou 311300People’s Republic of China Institute of Subtropical Forestry Chinese Academy of ForestryHangzhou 311400People’s Republic of China College of Forestry and Biotechnology Zhejiang A&F UniversityHangzhou 311300People’s Republic of China Sanya Research Base of the International Centre for Bamboo and Rattan Sanya 572000People’s Republic of China Zhejiang Provincial Key Laboratory of Forest Aromatic Plants-based Healthcare Functions Zhejiang A&F UniversityHangzhou 311300People’s Republic of China

Nitrogen(N)present in drinking water as dissolved nitrates can directly affect people’s health,making it important to control N pollution in water source areas.N pollution caused by agricultural fertilizers can be controlled by reducing the amount of fertilizer applied,but pollution caused by soil and water erosion in hilly areas can only be controlled by conservation forests.The catchment area around Fushi Reservoir was selected as a test site and mechanisms of N loss from a vertical spatial perspective through field observations were determined.The main N losses occurred from June to September,accounting for 85.9-95.9%of the annual loss,with the losses in June and July accounting for 46.0%of the total,and in August and September for 41.9%.The N leakage from the water source area was effectively reduced by 38.2%through the optimization of the stand structure of the conservation forests.Establishing well-structured forests for water conservation is crucial to ensure the security of drinking water.This preliminary research lays the foundation for revealing then loss mechanisms in water source areas and improving the control of non-point source pollution in these areas.

关键词： Water source areas Nitrogen loss Non-point source pollution Water quality Surface runoff

Lateral quantum confinement regulates charge carrier transfer and biexciton interaction in CdSe/CdSeS core/crown nanoplatelets

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Nano Research 2023年第7期16卷 10420-10428页

作者： Yige Yao Xiaotian Bao Yunke Zhu Xinyu Sui An Hu Peng Bai shufeng wang Hong Yang Xinfeng Liu Yunan Gao State Key Laboratory for Artificial Microstructure and Mesoscopic Physics School of PhysicsPeking UniversityBeijing 100871China CAS Key Laboratory of Standardization and Measurement for Nanotechnology National Center for Nanoscience and TechnologyBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Frontiers Science Center for Nano-optoelectronics Beijing 100871China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China Dalian National Laboratory for Clean Energy Dalian 116023China

Charge carrier dynamics essentially determines the performance of various optoelectronic applications of colloidal semiconductor nanocrystals.Among them,two-dimensional nanoplatelets provide new adjustment freedom for their unique core/crown heterostructures.Herein,we demonstrate that by fine-tuning the core size and the lateral quantum confinement,the charge carrier transfer rate from the crown to the core can be varied by one order of magnitude in CdSe/CdSeS core/alloy-crown nanoplatelets.In addition,the transfer can be affected by a carrier blocking mechanism,i.e.,the filled carriers hinder further possible transfer.Furthermore,we found that the biexciton interaction is oppositely affected by quantum confinement and electron delocalization,resulting in a non-monotonic variation of the biexciton binding energy with the emission wavelength.This work provides new observations and insights into the charge carrier transfer dynamics and exciton interactions in colloidal nanoplatelets and will promote their further applications in lasing,display,sensing,etc.

关键词： nanoplatelets core/crown charge carrier transfer ultrafast spectroscopy biexciton

Metabolomics signature of blood pressure salt sensitivity and its link to cardiovascular disease:A dietary salt-intervention trial

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Science China Life Sciences 2024年第8期 1666-1675页

作者： Zhennan Lin Jianxin Li Fangchao Liu Jie Cao shufeng Chen Jichun Chen Keyong Huang Yaqin wang Hongfan Li Yan wang Jianfeng Huang Dongfeng Gu Xiangfeng Lu Key Laboratory of Cardiovascular Epidemiology Department of EpidemiologyFuwai HospitalChinese Academy of Medical Sciences and Peking Union Medical College/National Center for Cardiovascular Diseases Medical School Southern University of Science and Technology

Individuals with a high degree of salt sensitivity(SS) have a greater risk of cardiovascular disease(CVD),but whether SS fosters CVD by influencing metabolomics homeostasis remains unclear.This study aimed to reveal the role of the SS-related metabolomics signature in the development of CVDs,based on the Meta Salt study,which was a dietary salt-intervention trial conducted at four centers in China in 2019.A total of 528 participants were recruited and underwent 3 days of baseline observations,a 10-day low-salt intervention,and a 10-day highsalt intervention.Plasma untargeted metabolomics,lipidomics,and BP measurements were scheduled at each stage.Participants were grouped into extreme SS,moderate SS,and salt-resistant(SR) individuals according to their BP responses to salt.Linear mixed models were used to identify SS-related metabolites and determine the relationship between the SS-related metabolomics signature and arterial stiffness.Mendelian randomization(MR) analyses were applied to establish the causal pathways among the SS-related metabolites,BP,and CVDs.Among the 713 metabolites,467 were significantly changed after the high-salt intervention.Among them,the changes in 30 metabolites from the low-salt to the high-salt intervention differed among the SS groups.Of the remaining nonsalt-related metabolites,the baseline levels of 11 metabolites were related to SS.These 41 metabolites explained 23% of the variance in SS.Moreover,SS and its metabolomics signature were positively correlated with arterial stiffness.MR analyses demonstrated that the SS-related metabolites may affect CVD risk by altering BP,indicating that the increase in BP was the consequence of the changes in SS-related metabolites rather than the cause.Our study revealed that the metabolomics signature of SS individuals differs from that of SR individuals and that the changes in SS-related metabolites may increase arterial stiffness and foster CVDs.This study provides insight into understanding the biology and targets of SS and its role in CVDs.

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The physical origin of stimulated emission in perovskites

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Journal of Semiconductors 2022年第5期43卷 5-9页

作者： Ju wang shufeng wang Liming Ding State Key Laboratory for Artificial Microstructure and Mesoscopic Physics Institute of Modern OpticsDepartment of PhysicsPeking UniversityBeijing 100871China Peking University Yangtze Delta Institute of Optoelectronics Nantong 226010China Collaborative Innovation Center of Extreme Optics Shanxi UniversityTaiyuan 030006China Frontiers Science Center for Nano-optoelectronics Peking UniversityBeijing 100871China Center for Excellence in Nanoscience(CAS) Key Laboratory of Nanosystem and Hierarchical Fabrication(CAS)National Center for Nanoscience and TechnologyBeijing 100190China

Perovskite lasers,due to their superiority in feasible production and wavelength tunability,find application in optical communication[1].Since the discovery of stimulated emission from CsPbCl3 microcrystalline at liqu... 详细信息

关键词： lasers breakthrough communication

Assessment of tree-ring mercury radial translocation and age effect in Masson pine:Implications for historical atmospheric mercury reconstruction

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Journal of Environmental Sciences 2024年第4期138卷 266-276页

作者： Xu Liu Xun wang Dingyong wang College of Resources and Environment Southwest UniversityChongqing 400715China State Key Laboratory of Environmental Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China

The tree ring has been regarded as an emerging archive to reconstruct historical atmospheric mercury(Hg)trends,but with the large knowledge gaps in the reliability.In this study,we comprehensively evaluated the Hg source,radial translocation and age effect of Masson pine(Pinus massoniana)tree ring at Mt.Jinyun in Chongqing,to assess the suitability of such tree ring as the archive of atmospheric Hg.Results showed that distinct variabilities among Masson pine tree-ring Hg concentration profiles.The Hg concentration significantly increased along with stem height(P<0.05),indicating the Hg in tree rings mainly derived from foliage uptake atmospheric Hg.We found a distinct age effect that the tree ring of young trees had the higher Hg concentration.Besides,we used the advection-diffusion model to demonstrate how Hg concentration shifted by the advection or/and diffusion in tree rings.The modeling results showed that the advection induced radial translocation during the young growth period of tree was a plausible mechanism to result in the tree-ring Hg record largely different from the trend of anthropogenic Hg emissions in Chongqing.We finally suggest that in further Hg dendrochemistry,better discarding the tree-ring Hg profile of the young growth period to reduce impacts of the radial translocation and age effect.

关键词： Masson pine Tree-ring mercury Radial translocation Tree age effect

Woody species Rhus chinensis Mill. seedlings tolerance to Pb:Physiological and biochemical response

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Journal of Environmental Sciences 2019年第4期31卷 63-73页

作者： Xiang Shi shufeng wang Dongxue wang Haijing Sun Yitai Chen Jianfeng Liu Zeping Jiang Research Institute of Subtropical Forestry Key Laboratory of Tree Breeding of Zhejiang ProvinceChinese Academy of Forestry Research Institute of Forestry Chinese Academy of Forestry Forestry College of Inner Mongolia Agricultural University

Screening potential plant species is a crucial consideration in phytoremediation technology.Our previous study demonstrated that Rhus chinensis Mill. seedlings had potentials for phytoremediation of Pb contaminated soil. However, its bioaccumulation and tolerance characteristics remain unclear. Seedling growth, LMWOAs secreted by roots, Pb subcellular distribution and chemical forms, and mineral elements in R. chinensis tissues were evaluated under different Pb concentrations(0, 25, 50, 100, 200 and 400 mg/L) in culture solution at14 days after planting. R. chinensis did not show visual symptoms of Pb toxicity under lower Pb treatments; however, Pb significantly declined the growth of seedlings under higher Pb treatments. Higher Pb stress also decreased the concentrations of nitrogen in leaves, but increased the concentrations of P and K in roots. Pb stress also decreased Mn concentrations in leaves. A great quantity of Pb was uptake and mostly retained in R. chinensis roots.Nonetheless, R. chinensis can still concentrate 459.3 and 1102.7 mg/kg Pb in leaves and stems,respectively. Most of Pb in R. chinensis tissues was stored in the cell wall with HAc-, HCl-, and NaC l-extractable form. LMWOAs secreted by R. chinensis roots showed a strong positive correlation with Pb concentrations in all plant tissues and with P in roots. Our results suggested that Pb deposited in the cell wall and integration with phosphate or oxalate might be responsible for the tolerance of R. chinensis under Pb stress in short period.

关键词： Lead Tolerance Subcellular distribution Chemical form Low molecular weight organic acids

Pushing the boundaries: an interview with Dae-Hyun Kim on terahertz devices

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National Science Review 2024年第3期11卷 42-45页

作者： Defu wang the Center for Carbon-based Electronics School of Electronics Peking University

Ⅲ–Ⅴ compound semiconductors, such as InGaAs/InAlAs, exhibit exceptional carrier transport properties, establishing them as fundamental elements in terahertz(THz) applications crucial for the development of 6G netwo...

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