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Hydroxyl radical production by abiotic oxidation of pyrite under estuarine conditions:The effects of aging,seawater anions and illumination

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Journal of Environmental Sciences 2024年第1期135卷 715-727页

作者： Ruixue Liu Yinshun Dai yucheng feng Shiwen Sun Xiaodong Zhang Chunjiang An Shan Zhao Shandong Key Laboratory of Water Pollution Control and Resource Reuse School of Environmental Science and EngineeringShandong UniversityQingdao 266237China Department of Building Civil and Environmental EngineeringConcordia UniversityMontrealQC H3G 1M8Canada

Pyrite is widely distributed in estuarine sediments as an inexpensive natural Fenton-like reagent,however,the mechanism on the hydroxyl radical(HO^(·))production by pyrite under estuarine environmental conditions is still poorly *** batch experiments were performed to investigate the effects of estuarine conditions including aging(in air,in water),seawater anions(Cl^(-),Br^(-)and HCO_(3)^(-))and light on the HO^(·)production by pyrite *** one-electron transfer dominated the process from O_(2) to HO^(·)induced by oxidation of *** Fe(oxyhydr)oxide coatings on the surface of pyrite aged in air and water consumed hydrogen peroxide while mediating the electron transfer,and the combined effect of the two resulted in a suppression of HO^(·)production in the early stage of aging and a promotion of HO^(·)production in the later stage of *** of the surface oxide layers by aggressive anions was the main reason for the inhibition of HO^(·)production by Cl^(-)and Br^(-),and the generation of Cl^(·)and Br^(·)may also play a role in the scavenging of HO^(·).HCO_(3)^(-)increased the average rate of HO^(·)production through surface-CO_(2) complexes formed by adsorption on the surface of *** significant enhancement of HO^(·)production under light was attributed to the formation of photoelectrons induced by photochemical reactions on pyrite and its surface oxide *** findings provide new insights into the environmental chemical behavior of pyrite in the estuary and enrich the understanding of natural remediation of estuarine environments.

关键词： Hydroxyl radical Pyrite oxidation Aging Anions Irradiation

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柔性辊压成形技术及装备发展现状与展望

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现代制造工程 2024年第1期 151-161页

作者：郭文凤刘春梅王云郑硕冯宇程南京航空航天大学材料科学与技术学院南京211100 浙江金马逊智能制造股份有限公司浙江省航空航天金属导管塑性成形技术与装备重点实验室丽水323000

柔性辊压成形是一种新型塑性加工技术,与传统带材成形技术相比,该工艺通过多道次成形辊小角度变化完成成形要求,结合了自动化及高水平智能控制系统,工艺先进性高,该工艺的升级可以更好地利用框架式结构来实现轻量化。针对成形构件的不... 详细信息

柔性辊压成形是一种新型塑性加工技术,与传统带材成形技术相比,该工艺通过多道次成形辊小角度变化完成成形要求,结合了自动化及高水平智能控制系统,工艺先进性高,该工艺的升级可以更好地利用框架式结构来实现轻量化。针对成形构件的不同特征,包括等截面、变截面、轴线侧弯和变深度构件,调研了辊压成形工艺的研究现状,包括机理机制、成形受力及有限元仿真。描述了该工艺成形过程中出现的缺陷类型及产生机理,给出了控制各类缺陷所使用的改进措施。最后总结了该工艺目前已应用的领域和未来重点开发应用的领域,指出该工艺在采用高自动化水平制造高精度、高质量构件方面具有良好的发展前景。

关键词：辊压成形柔性型材轻量化缺陷

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硬脂酸-CaCO_(3)协同改性对植物纤维/聚乳酸复合材料力学性能的影响

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中国造纸 2024年第4期43卷 130-139页

作者：黄艳志冯郁成吴树颖高琪雅饶婉月董昕睿杨飞华南理工大学制浆造纸工程国家重点实验室广东广州510640

以硬脂酸、CaCl_(2)、NaHCO_(3)和NaOH为原料,对植物纤维进行硬脂酸-CaCO_(3)协同改性,在纤维表面沉积CaCO_(3)颗粒和疏水的硬脂酸钙层,并通过造纸法制备改性植物纤维/聚乳酸(PLA)复合材料。结果表明,协同改性生成的硬脂酸钙包裹了CaCO_... 详细信息

以硬脂酸、CaCl_(2)、NaHCO_(3)和NaOH为原料,对植物纤维进行硬脂酸-CaCO_(3)协同改性,在纤维表面沉积CaCO_(3)颗粒和疏水的硬脂酸钙层,并通过造纸法制备改性植物纤维/聚乳酸(PLA)复合材料。结果表明,协同改性生成的硬脂酸钙包裹了CaCO_(3)颗粒并覆盖在植物纤维表面,提高了纤维的疏水性,复合材料的力学性能随c(硬脂酸)∶c(NaHCO_(3))的增加而先增加后减小;反应温度对复合材料强度影响较小;复合材料的抗张指数和耐破指数随c(NaOH)∶c(NaHCO_(3))的增加而先增加后减小,耐折度则持续减小;最佳改性条件为:c(硬脂酸)∶c(NaHCO_(3))∶c(NaOH)=4∶6∶6、反应温度75℃,此时制备的复合材料抗张指数、耐破指数和耐折度分别为51.0 N·m/g、3.56 kPa·m^(2)/g、244次。

关键词：植物纤维聚乳酸硬脂酸钙力学性能

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CFD modeling of a headbox with injecting dilution water in a central step diffusion tube

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Chinese Journal of Chemical Engineering 2016年第10期24卷 1313-1324页

作者： Xu Yang Jinsong Zeng Kefu Chen yucheng feng State Key Laboratory of Pulp and Paper Engineering School of Light Industry and Food ScienceSouth China University of Technology

For engineering applications of water dilution controlling system,the fluid dynamics of a mixed flow was studied with computational fluid dynamics(CFD) simulations and self-designed experimental *** order to examine the predictability of CFD model for the headbox in industrial scale,two pulp suspensions before mixing were treated as homogeneous flows *** k-ε turbulence models with the mass diffusion in turbulent flows-species transport approach were applied in the simulations.A numerical simulation of this headbox model was analyzed with semi-implicit method for pressure linked equations scheme with pressure–velocity *** show that the model can predict hydrodynamic characteristics of headbox with injecting dilution water in a central diffusion tube,and the distribution of water content at the outlet of the slice lip is ideally normal at different speeds.

关键词：计算液体动力学 Headbox 骚乱模型种类运输肉暂停

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Nanoscopic tribological characteristics of a cryogenically cycled Zr-based metallic glass

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Science China(Physics,Mechanics & Astronomy) 2024年第6期67卷 113-126页

作者： Qian Jia Qiaosheng Xia Qing Zhou yucheng Wang Yue Ren Yu Meng Haifeng Wang feng Zhou State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an 710072China Shaanxi Key Laboratory of Surface Engineering and Remanufacturing Xi’an UniversityXi’an 710065China State Key Laboratory of Solid Lubrication Lanzhou Institute of Chemical PhysicsChinese Academy of SciencesLanzhou 730000China

Optimized macroscopic tribological behavior can be anticipated in metallic glasses(MGs)by cryogenic cycling treatment(CCT),which is attributed to enhanced ***,the intrinsic friction mechanisms of MGs induced by cryogenic rejuvenation are still poorly *** the present study,nanoscopic wear tests were conducted on the Zr-based MGs surface with different CCT cycles using atomic force microscopy(AFM).After CCT treatment with 100 cycles,the MG displays the highest adhesion and ploughing frictions,but significantly improved anti-wear *** tests and molecular dynamics simulations disclose that the increased adhesion is attributed to the dominance of liquid-like regions in the CCT-treated MGs,and the impact of reduced hardness and weak elastic recovery results in the deteriorated ploughing *** enhanced plasticity effectively dissipates the strain from the AFM tip through multiple shear bands and weakens the adhesion during deformation,giving rise to excellent wear *** study elucidates the promoting effect of CCT on the outstanding antiwear performance of MGs,and is helpful for the development of novel alloys.

关键词： metallic glasses cryogenic cycling treatment nanoscope wear friction mechanism

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Soil microbial community structure and activity in a 100-year-old fertilization and crop rotation experiment

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Journal of Plant Ecology 2015年第6期8卷 623-632页

作者： Cancan Zhao Shenglei Fu Reji P.Mathew Kathy S.Lawrence yucheng feng Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems South China Botanical GardenChinese Academy of Sciences723 Xingke RoadGuangzhou 510650China State Key Laboratory of Cotton Biology Key Laboratory of Plant Stress BiologySchool of Life ScienceHenan University1 Jinming AvenueKaifengHenan 475004China Department of Crop Soil and Environmental SciencesAuburn UniversityAuburnAL 36849USA Department of Entomology and Plant Pathology Auburn UniversityAuburnAL 36849USA

Aims Nitrogen(N)fertilization and lime addition may affect soil micro-bial and nematode communities and ecosystem functions through changing environmental conditions,such as soil pH and soil organic *** objectives of this experiment were to examine the impact of N input and liming on soil microbial and nematode communities and to identify the key environmental determinant of community composition in a century-old fertilization and crop rota-tion *** The field experiment consisting of a 3-year crop rotation regime was established in 1911 in southeastern *** treatments,(i)no-input control,(ii)NPK with winter legume,(iii)PK with legume and lime and(iv)NPK with legume and lime,were included in this *** samples collected at the 0-5 cm depth were used to determine the bacterial growth rate by the 3H-thymidine incorporation *** of 13C into neutral lipids,glycolipids and phospholipid fatty acids(PlFas)was measured after incubation of soil with 13C-labeled acetate for 24 ***-living nematodes in fresh soil were extracted using a density sucrose centrifugal flotation method and identified to trophic group *** Findingsliming resulted in a 10-fold increase in bacterial growth rates compared with the no-input control,whereas N fertilization had no significant *** analysis of PlFa profiles showed that soil microbial community composition was different among the four treatments;the difference was primarily driven by soil *** indicative of gram-negative bacteria covaried with soil pH,but not those of fungi and *** enhanced 13C incorpora-tion into neutral lipids,glycolipids and phospholipids by 2-15 *** addition,13C incorporation into 16:0,16:1ω9,18:1ω9,18:1ω7 and 18:2ω6 were greater than other PlFas,suggesting that gram-negative bacteria and fungi were more active and sensitive to simple C *** nematodes were the dominant trophic group in the soil,but no si

关键词： long-term experiment phospholipid fatty acid analysis stable isotope probing bacterial growth rate soil microbial community

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中国1960-2016年风能资源的时空分布特征

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Atmospheric and Oceanic Science Letters 2020年第2期13卷 136-145页

作者： feng yucheng QUE Linjing feng Jinming School of Information Engineering China University of Geosciences in BeijingBeijingChina Institute of Atmospheric Physics Chinese Academy of SciencesBeijingChina Heilongjiang Province Meteorological Service Center Heilongjiang Province Meteorological BureauHarbinChina

基于462个气象观测站1960–2016年共57年的近地面风速日资料,利用克里格空间内插,最小二乘法,相关系数检验和经验正交函数分解(EOF)等方法分析了年均和各个季节中国区域风速及有效风能密度的时空变化特征。研究结果表明:在中国北部和部... 详细信息

基于462个气象观测站1960–2016年共57年的近地面风速日资料,利用克里格空间内插,最小二乘法,相关系数检验和经验正交函数分解(EOF)等方法分析了年均和各个季节中国区域风速及有效风能密度的时空变化特征。研究结果表明:在中国北部和部分沿海地区年平均风速在3 m s-1以上,有效风能密度在75 W m-2以上,而在中国南部地区平均风速和有效风能密度均较小。近五十多年以来,中国区域年均和季节平均风速呈明显下降趋势,北部地区春季递减率最大,沿海地区冬季递减率最大。广东部分地区年平均风速有增大的趋势,西南,华南和华中西部地区年平均风速变化不大。平均风速大的区域,递减率也大。年平均风速和年有效风能密度的主要空间分布模态表现出高度的一致性,均呈现逐年减小趋势。中国风速及风能资源的减小趋势,主要与全球变暖及土地利用变化有关。

关键词：风速风能资源有效风能密度经验正交函数分解时空变化特征

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Derivation of Expanded Isospectral-Nonisospectral Integrable Hierarchies via the Column-vector Loop Algebra

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Acta Mathematicae Applicatae Sinica 2024年第3期40卷 778-800页

作者： Hai-feng WANG Yu-feng ZHANG School of Science Jimei UniversityXiamen 361021China School of Mathematics China University of Mining and TechnologyXuzhou 221116China

A scheme for generating nonisospectral integrable hierarchies is *** on the method,we deduce a nonisospectral hierarchy of soliton equations by considering a linear spectral *** follows that the corresponding expanded isospectral and nonisospectral integrable hierarchies are deduced based on a 6 dimensional complex linear space ■.By reducing these integrable hierarchies,we obtain the expanded isospectral and nonisospectral derivative nonlinear Schr?dinger *** using the trace identity,the biHamiltonian structure of these two hierarchies are also ***,some symmetries and conserved quantities of the resulting hierarchy are discussed.

关键词： expanded isospectral-nonisospectral integrable hierarchies column-vector loop algebra bi-Hamiltonian structure symmetry

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Carbon-based materials with combined functions of thermal management and electromagnetic protection: Preparation, mechanisms, properties, and applications

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Nano Research 2024年第3期17卷 883-903页

作者： Junwei Yue Yiyu feng Mengmeng Qin Wei feng School of Materials Science and Engineering and Tianjin Key Laboratory of Composite and Functional Materials Tianjin UniversityTianjin 300350China

The proliferation of high-power,highly informationized,and highly integrated electronic devices and weapons equipment has given rise to increasingly conspicuous issues about electromagnetic(EM)pollution and thermal *** issues,in turn,impose constraints on the performance of such equipment and jeopardize personnel *** materials,owing to their diverse and modifiable structures,offer adjustable thermal and electric conductivity,rendering them highly promising for applications in fields such as thermal management and EM protection which have garnered extensive research and *** pursuit of integrated device and equipment development has elevated the demand for multifunctional materials,prompting significant research into carbon-based composite materials that include both thermal management and EM protection ***,there are no relevant reviews on this topic at ***,this work consolidates research findings from recent years on carbon matrix composites exhibiting dual attributes of thermal management and EM *** attributes include thermally conductive electromagnetic interference(EMI)shielding materials,thermally insulating EMI shielding materials,thermally conductive EM wave(EMW)absorbing materials,and thermally insulating EMW absorbing *** paper elucidates the fundamental principles underpinning thermal conduction,thermal insulation,EMW absorbing,and EMI ***,it engages in discussions surrounding areas of contention,design strategies,and the functional properties of various material ***,the paper concludes by presenting the challenges encountered and potential research strategies about composites endowed with both thermal management and EM protection functionalities,while also envisaging the development of novel multifunctional EM protection materials.

关键词： carbon-based composites electromagnetic interference shielding microwave absorption thermal conduction thermal insulation

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Design and identification of a double-acting piezoelectric-hydraulic hybrid actuator

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Chinese Journal of Aeronautics 2024年第3期37卷 456-467页

作者： Junjian ZHANG Zhihua feng Key Laboratory of Precision Scientific Instrumentation of Anhui Higher Education Institutes University of Science and Technology of ChinaHefei 230026China

Traditional single-acting piezoelectric-hydraulic hybrid actuators usually have the problem of inertial force caused by flow pulsation of the liquid,which degrades their output *** suppress or solve the associated inertial force and enhance its output capabilities,this paper proposes a new type of double-acting piezoelectric-hydraulic hybrid actuator with four check valves acting as mechanical *** new hybrid actuator was fabricated and its output performance was *** the voltage is 700 Vp-pand the bias pressure is 2 MPa,the pulsation ratesδof the new actuator at 400 Hz,500 Hz and 600 Hz are 2.29,2.08 and 1.78,respectively,whileδof the single-acting hybrid actuator under the same conditions are 10.98,11.05 and ***,the liquid pulsation rate of the new hybrid actuator is significantly reduced,which is beneficial for improving the flow uniformity and weakening the influence of inertial force on the hybrid *** strategy ultimately leads to a maximum no-load velocity of 168.1 mm/s at 600 Hz and a maximum blocking force of 141 N at 450 Hz for the new hybrid *** addition,this strategy has the potential to be used in other electrohydrostatic actuators to improve their performance.

关键词： Double-acting Flow pulsation Inertial force Piezoelectric actuators Piezoelectric devices Piezoelectric hydraulic actuation Piezoelectric pump

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