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滨海垦区表层盐渍土理化性质和盐分离子动态特征

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土壤 2024年第2期56卷 398-405页

作者：路迅李建国潘霞岳亚朋王松林左希爱徐璐江苏师范大学地理测绘与城乡规划学院江苏徐州221116

江苏沿海地区拥有面积广阔的围垦区,对围垦区盐渍土理化性质变化规律的研究有助于把握滨海围垦区土壤质量变化规律和特征。本研究通过采集32个江苏省盐城市不同围垦年限的土壤表层样品,对滨海垦区表层盐渍土理化性质、盐分离子含量、钠... 详细信息

江苏沿海地区拥有面积广阔的围垦区,对围垦区盐渍土理化性质变化规律的研究有助于把握滨海围垦区土壤质量变化规律和特征。本研究通过采集32个江苏省盐城市不同围垦年限的土壤表层样品,对滨海垦区表层盐渍土理化性质、盐分离子含量、钠吸附比(SAR)、电导率(EC)等土壤质量关键指标进行分析,结果表明:(1)在百年以上的围垦过程中,滨海垦区表层盐渍土的C/N和p H均呈现出先上升后下降的趋势,拐点在围垦后20a左右,其中土壤C/N远低于我国传统耕地的平均水平;总有机碳(SOC)和全氮(TN)含量在围垦过程中整体呈现上升趋势;(2)EC和SAR呈快速降低的趋势,围垦至40 a左右时,土壤质量基本达到传统耕地的土壤质量水平,盐分离子普遍降至1g/kg左右;NO_(3)^(–)与NO_(2)^(–)均为土壤中的重要氮素形态,NO_(3)^(–)含量呈现先稳定后显著下降趋势,在围垦至100 a以上时显著下降;NO_(2)^(–)在围垦至20 a左右时显著上升,围垦至40 a左右时显著下降;百年围垦过程中,盐渍土盐分组成由氯化物盐土转变为氯化物硫酸盐土;(3)滨海盐渍土中理化性质与围垦年限对盐分离子演化存在复杂的关系,土壤围垦年限、pH-EC和SOC-TN含量3组组分的共同作用对盐分离子变化贡献度最大。

关键词：滨海垦区围垦年限土壤理化性质盐分离子

Accelerated design for magnetocaloric performance in Mn-Fe-P-Si compounds using machine learning

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Journal of Materials Science & Technology 2022年第1期96卷 241-247页

作者： Defang Tu Jianqi Yan Yunbo Xie Jun li Shuo Feng Mingxu Xia jianguo li Alex Po Leung School of Material Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Macao University of Science and Technology MacaoChina Shanghai Key Laboratory of Advanced High-temperature Materials and Precision Forming Shanghai 200240China School of Engineering University of LeicesterLeicester LE17RHUnited Kingdom

Magnetocaloric performance is of vital importance for Mn-Fe-P-Si ***,when processes and compositions are considered,designing alloys with large magnetic entropy changes(ΔS_(m)),low thermal hysteresis(ΔT_(hys)),and Curie temperatures(T_(C))around room temperature become relatively *** this study,we adopt machine learning methods to predict the magnetocaloric performance of Mn-Fe-P-Si compounds for the first *** achieve this goal,503,465,and 660 data points for datasets with T_(C),ΔT_(hys),andΔS_(m)are collected,*** collected datasets contain parameters of compositions,preparations,heat treatment,and magnetic field *** search for the optimal configuration using various methods and also compare their mean squared errors(MSE)and allowable *** results show that the performance of neural networks(NNs)is better than other ***,we select NN to explore the T_(C),ΔT_(hys),andΔS_(m)values as a function of Mn,Si,metal/non-metal ratios,and B(Boron).We also propose to use the composition window with excellent magnetocaloric *** results not only help us gain deep insights into Mn-Fe-P-Si alloys but also accelerate the design process of alloys suitable for magnetocaloric *** work has the potential to solve the challenges and boost the research of Mn-Fe-P-Si alloys.

关键词： Mn-Fe-P-Si alloy Material design Magnetocaloric performance Machine learning Neural network

Dynamic recrystallization-induced temperature insensitivity of yield stress in single-crystal Al1.2CrFeCoNi micropillars

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Science China(Technological Sciences) 2021年第1期64卷 11-22页

作者： HUANG RuiRui ZHANG Qian ZHANG Xuan li jianguo CAO TangQing YAO JiaHao XUE YunFei GAO HuaJian li XiaoYan Center for Advanced Mechanics and Materials Applied Mechanics LaboratoryDepartment of Engineering MechanicsTsinghua UniversityBeijing 100084China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Shenyang National Laboratory for Materials Science Institute of Metal ResearchChinese Academy of SciencesShenyang 110016China School of Mechanical and Aerospace Engineering College of EngineeringNanyang Technological UniversitySingapore 639798Singapore Institute of High Performance Computing A*STARSingapore 138632Singapore

High-entropy alloys, a new class of metallic materials, exhibit excellent mechanical properties at high temperatures. In spite of the worldwide interest, the underlying mechanisms for temperature dependence of mechanical properties of these alloys remain poorly understood. Here, we systemically investigate the mechanical behaviors and properties of Al_(1.2)CrFeCoNi(comprising a body-centered cubic phase) and Al_(0.3)CrFeCoNi(comprising a face-centered cubic phase) single-crystal micropillars with three orientations([100], [110], and [111]) at temperatures varying from 300 to 675 K by using in situ compression of micropillars inside a scanning electron microscope. The results show that the yield stresses of Al_(1.2)CrFeCoNi micropillars are insensitive to temperature changes, and their flow stresses and work hardening rates increase slightly with increasing temperature from 300 to550 K, which differs from the typical temperature dependence of yield/flow stresses in metals and alloys. In contrast,Al_(0.3)CrFeCoNi micropillars exhibit typical thermal softening. Furthermore, it is found that the Al_(1.2)CrFeCoNi micropillars exhibit a transition from homogenous deformation to localized deformation at a critical temperature, while the Al_(0.3)CrFeCoNi micropillars always maintain a well-distributed and fine slip deformation. Detailed transmission electron microscopy analyses reveal that dynamic recrystallization(involving dislocation tangles, and formation of dislocation cell structures and sub-grains)plays a key role in the observed temperature insensitivity of the yield stress and increasing flow stress(and work hardening rate)with increasing temperature in the Al_(1.2)CrFeCoNi micropillars, and that thermally activated dislocation slip leads to thermal softening of the Al_(0.3)CrFeCoNi micropillars. The differences in deformation modes and temperature dependence of the mechanical properties between Al_(1.2)CrFeCoNi and Al_(0.3)CrFeCoNi essentially originate from the d

关键词： high entropy alloy temperature insensitivity dynamic recrystallization micropillar deformation twin

Kinetic role of Cu content in reaction process, behavior and their relationship among Cu-Zr-C system

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Journal of Materials Science & Technology 2019年第10期35卷 2375-2382页

作者： Qiaodan Hu Xianrui Zhao Siyu Sun Hua Zheng Sheng Cao jianguo li Mengxian Zhang School of Materials Science and Engineering Shanghai Jiao Tong UniversityShanghai 200240China Scholl of Naval Architecture&Ocean Engineering Jiangsu Maritime InstituteNanjing 211170China Zhejiang Provincial Key Laboratory for Cutting Tools Taizhou UnniversityTaizhou 318000China Primary School of Education Chongqing Normal UniversityChongqing 400700China Monash Centre for Additive Manufacturing(MCAM) Monash UniversityClaytonVIC 3800Australia Jiangxi Province Engineering Research Center of Materials Surface Enhancing&Remanufacturing School of Mechanical and Materials EngineeringJiujiang UniversityJiujiang 332005China

The influence of Cu content on the reaction process, reaction behavior and obtained products in the Cu-ZrC system, as well as their relationships, were investigated. The results showed that Zr C was synthesized through the diffusion and dissolution of C into a Cu-Zr liquid. Increasing the Cu content enhanced the amount of Cu-Zr liquid formed at the early stage but decreased the amount of C atoms dissolving into the melt at unit time. Consequently, the ignition time initially decreased and then increased. Conversely, with an increased Cu content, the energy required for igniting the neighboring unreacted powders increased,while the heat released by the reaction and the dwell time of the compact at high temperatures *** effects then resulted in the reduction of combustion wave velocity, combustion temperature and Zr C particle size. Furthermore, the synthesis of ZrC is a multistage process, which provides a nonuniform distributed Zr C particle size. The sub-μm Zr C particle reinforced Cu matrix composite was fabricated by adding a ZrC-Cu master alloy prepared through a self-propagating high-temperature synthesis reaction into liquid Cu.

关键词： Self-propagating high-temperature synthesis Reaction process Reaction behavior Solidification

Operation, Analysis and Experiments of DC Transformers Based on Modular Multilevel Converters for HVDC Applications

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CSEE Journal of Power and Energy Systems 2019年第1期5卷 87-99页

作者： jianguo li Xianghong Zuo Yuming Zhao Xiuping Lv Jiuhe Wang College of Automation Beijing Information Science and Technology UniversityBeijing 100192China Beijing Electric Power Economic Research Institute Beijing 100055China Shenzhen Power Supply Company Shenzhen 518048China

This paper studies the operation,analysis and experiments of multilevel high frequency link transformers(MHFLT)based on modular multilevel converters(MMC)for high voltage DC *** multilevel dual active phase shift is proposed to operate the MHFLT using a high switching frequency,which brings about many advantages and makes the operation quite different from that of the traditional DC transformer(DCT)based on a dual active bridge and the fundamental frequency MMC widely used in flexible HVDC ***,MHFLT is suitable for high voltage levels,which is due to its good switching characterization,ability to cut itself off from an external fault,and it can also achieve redundancy operations when a sub-module fault *** this paper,the operation,modulation method,multilevel high frequency link voltage,current,and power characterization,high frequency commutation,and switching characterization are analyzed comprehensively;the pulse rotation and distributed delay control,and fault handling strategies of MHFLT are then ***,a prototype is built,and the experimental results verify the correctness and effectiveness of the proposed solution.

关键词： DC–DC converter DC transformer DC transmission high-frequency-link high voltage DC multilevel converter

烟梗化学组分分析及其制浆与配抄纸张性能研究

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中国造纸 2024年第7期43卷 64-73页

作者：潘鹏宇施建在李安琪陈欣杨伟凯张静楠陈礼辉李建国张国强福建农林大学材料工程学院植物纤维功能材料国家林和草原局重点实验室福建福州350108 福建金闽再造烟叶发展有限公司福建福州350600 福建中烟工业有限责任公司福建厦门361012

本研究通过水热预处理-机械磨浆方式制备烟梗纸浆纤维,并与漂白硫酸盐阔叶木浆配抄纸张。烟梗化学组分析表明,烟梗原料中木质素和综纤维素含量较低(木质素含量为5%~8%、综纤维素含量为29%~35%)、抽出物和灰分含量较高(抽出物含量>50%、... 详细信息

本研究通过水热预处理-机械磨浆方式制备烟梗纸浆纤维,并与漂白硫酸盐阔叶木浆配抄纸张。烟梗化学组分析表明,烟梗原料中木质素和综纤维素含量较低(木质素含量为5%~8%、综纤维素含量为29%~35%)、抽出物和灰分含量较高(抽出物含量>50%、灰分含量为~15%),比较适宜制备机械浆纤维。探究水热预处理条件、H_(2) O_(2)漂白工艺参数以及配抄条件对烟梗纤维和纸张性能的影响。结果表明,80℃、90 min的水热预处理后通过H_(2) O_(2)漂白60 min(H_(2) O_(2)用量3%),可以制备纤维重均长度为0.395 mm、重均宽度为32.3µm、扭结角为98°、卷曲指数为15.3%的烟梗浆纤维;利用制备的烟梗浆纤维与漂白硫酸盐阔叶木浆在质量比3∶7配抄条件下,所制纸张松厚度、白度、不透明度、撕裂指数和抗张指数分别为1.68 cm^(3)/g、62.1%、94.6%、5.92 mN·m^(2)/g和33.8 N·m/g。

关键词：烟梗原料漂白硫酸盐阔叶木浆纤维形态物理性能

Crystal Structure, Thermal Decomposition Behaviors and Sensitivity Properties of a Novel Energetic Compound [Co（DAT）6] （CIO4）2

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Chinese Journal of Chemistry 2011年第1期29卷 59-64页

作者： Qi, Shuyuan li, Zhimin Zhou, Zunning Cui, Yan Zhang, Guotao Zhang, Tonglai Zhang, jianguo Yang, li State Key Laboratory of Explosion Science and Technology Beijing Institute of Techonoly Beijing 100081 China

A novel energetic coordination compound [Co（DAT）6]（CIO4）2 has been synthesized by using 1,5-diaminotetrazole （DAT） as a ligand and its structure has been characterized using X-ray single crystal diffraction, elemental analysis and FT-IR spectroscopy. The central cobalt（II） cation is coordinated by six N atoms from six DAT molecules to form a six-coordinated and distorted octahedral structure. Di-dimension layer structure was formed by the extensive intermolecular hydrogen bonds between DAT ligands and CIO4 anions along a-axis and b-axis. Thermal decomposition mechanism of [Co（DAT）6]（CIO4）2 was investigated based on differential scanning calorimetry （DSC）, thermogravimetric analysis （TGA） and Fourier transform infrared （FF-IR） spectra. The kinetic parameters of the first exothermic process were studied by applying the Kissinger＇s and Ozawa-Doyle＇s methods. Additionally, the sensitivities of this complex were tested. The results of all the studies show that [Co（DAT）6]（CIO4）2 has an extreme potential application as an energetic material.

关键词： cobalt crystal structure 1,5-diaminotetrazole thermochemistry sensitivity properties

经阴道超声联合3.0T磁共振成像用于异位妊娠诊断的价值

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中国辐射卫生 2024年第2期33卷 195-199页

作者：李建国李蓉蒋代彬杨腊梅谭彦涂媛四川省达州市达川区人民医院超声医学科四川达州635000 四川省达州市达川区人民医院医学影像科四川达州635000 四川省成都市第二人民医院病理科四川成都610017

目的比较经阴道超声、3.0T磁共振成像(MRI)扫描以及经阴道超声联合3.0T MRI扫描用于异位妊娠诊断的价值,为异位妊娠早期筛查提供参考依据。方法以2019年2月—2022年12月在四川省达州市达川区人民医院就诊的130例疑似异位妊娠患者为研究... 详细信息

目的比较经阴道超声、3.0T磁共振成像(MRI)扫描以及经阴道超声联合3.0T MRI扫描用于异位妊娠诊断的价值,为异位妊娠早期筛查提供参考依据。方法以2019年2月—2022年12月在四川省达州市达川区人民医院就诊的130例疑似异位妊娠患者为研究对象,所有患者均接受经阴道超声、3.0T MRI扫描检查,以手术病理或临床随访结果为金标准,评价经阴道超声、MRI检查与临床诊断结果的一致性,比较经阴道超声、3.0T MRI扫描以及经阴道超声联合3.0T MRI扫描诊断异位妊娠的敏感度、特异度、准确度。结果130例疑似异位妊娠患者中,108例经手术病理确诊为异位妊娠、22例经随访确诊为非异位妊娠。经阴道超声诊断异位妊娠的敏感度、特异度、准确度分别为85.19%(92/108)、54.55%(12/22)、80.00%(104/130),与临床诊断结果的一致性为0.358。3.0T MRI扫描诊断异位妊娠的敏感度、特异度、准确度分别为92.59%(100/108)、81.81%(18/22)、90.77%(118/130),与临床诊断结果的一致性为0.694。经阴道超声联合3.0T MRI扫描诊断异位妊娠的敏感度、特异度、准确度分别为98.15%(106/108)、72.73%(16/22)、93.85%(122/130),与临床诊断结果的一致性为0.764。经阴道超声联合3.0T MRI扫描诊断异位妊娠的敏感度(χ^(2)=11.88,P<0.01)和准确度(χ^(2)=10.96,P<0.01)均明显高于经阴道超声。结论经阴道超声联合3.0T MRI扫描可为异位妊娠提供更丰富诊断信息,与临床诊断结果一致性较高,且相较单纯经阴道超声检查能提高诊断敏感度、准确度。

关键词：磁共振成像经阴道超声异位妊娠诊断效能

Effect of cooling rate on the 3D morphology of the proeutectic Al3Ni intermetallic compound formed at the Al/Ni interface after solidification

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Journal of Materials Science & Technology 2021年第10期69卷 60-68页

作者： liao Yu Qiaodan Hu Zongye Ding Fan Yang Wenquan Lu Naifang Zhang Sheng Cao jianguo li Shanghai Key Laboratory of Materials Laser Processing and Modification School of Materials Science and EngineeringShanghai Jiao Tong UniversityShanghai 200240China School of Mechanical Engineering Shanghai Jiao Tong UniversityShanghai 200240China School of Materials The University of ManchesterOxford RoadManchesterMl 39PLUK

Effect of cooling rate on the 3 D morphology and the growth mechanism of the proeutectic Al3Ni intermetallic compound(IMC) that forms at the Al/Ni interface after solidification was investigated by synchrotron X-ray microtomography in combination with EBSD analysis. The proeutectic Al3Ni phase that forms under an average cooling rate of 0.1 Ks^(-1) shows a characteristic faceted growth behavior and presents a typical 3 D morphology as partially hollow quadrangular prisms. On the contrary, that forms under an average cooling rate of 10 Ks^(-1) shows complicated dendritic morphology with asymmetrically distributed arms and faceted V-shape groove at the distal end, indicating a gradual transition of the growth behavior from non-faceted to faceted during the solidification process. These results reveal that the morphology of the proeutectic Al3Ni is highly sensitive to the solidification condition so that fine control of the desired morphology may be achieved by carefully manipulating the cooling profile.

关键词： 3D morphology Al3Ni intermetallic compounds Solidification Cooling rate Synchrotron radiation Al/Ni interface