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Response of density-related fine root production to soil and leaf traits in coniferous and broad-leaved plantations in the semiarid loess hilly region of China

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Journal of Forestry Research 2022年第3期33卷 1071-1082页

作者： Meimei Sun Bo-Chao Zhai Qiu-Wen chen Guoqing Li sheng Du State Key Laboratory of Soil Erosion and Dryland Farming On the Loess Plateau Northwest A&F UniversityYanglingShaanxi712100People’s Republic of China College of Forestry Northwest A&F UniversityYanglingShaanxi712100People’s Republic of China Institute of Soil and Water Conservation Chinese Academy of Sciences and Ministry of Water ResourcesYanglingShaanxi712100People’s Republic of China

Fine roots are the most active and functional component of root systems and play a significant role in the acquisition of soil resources. Density is an important structural factor in forest plantations but information on changes in fine roots along a density gradient is limited. In this study, plantations of black locust (Robinia pseudoacacia L.) and Chinese pine (Pinus tabuliformis Carr.) with four density classes were analyzed for the influence of soil and leaf traits on fine root growth. Fine root biomass increased with stand density. High fine root biomass was achieved through increases in the fine root production and turnover rate in the high-density black locust plantations and through an increase in fine root production in the pine plantations. In the high-density Chinese pine stand, there was a high fine root turnover which, coupled with high fine root production, contributed to a high fine root biomass. Overall, fine root production and turnover rate were closely related to soil volumetric water content in both kinds of plantations, while fine root biomass, especially the component of necromass, was related to soil nutrient status, which refers to phosphorous content in black locust plantations and nitrogen content in Chinese pine plantations. There was a close linkage between leaf area index and fine root dynamics in the black locust plantations but not in the pine plantations.

关键词： Fine roots Black locust Chinese pine Semiarid Soil moisture Leaf area index

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高温长期服役S30432钢管的组织与性能

金属热处理 2024年第5期49卷 17-22页

作者：杨希锐江宝世胡锋涛李艳军盛超杰王晨润电能源科学技术有限公司河南郑州450000 华润电力菏泽有限公司山东菏泽274000 武汉大学动力与机械学院湖北武汉430000

通过室温拉伸、室温冲击、硬度测试、高温拉伸、金相显微镜、扫描电镜和能谱仪等手段研究了超超临界锅炉服役79000 h S30432钢管的组织和性能。结果表明,S30432钢管高温服役79000 h后,室温硬度和抗拉强度升高,塑、韧性均显著降低,断后... 详细信息

通过室温拉伸、室温冲击、硬度测试、高温拉伸、金相显微镜、扫描电镜和能谱仪等手段研究了超超临界锅炉服役79000 h S30432钢管的组织和性能。结果表明,S30432钢管高温服役79000 h后,室温硬度和抗拉强度升高,塑、韧性均显著降低,断后伸长率已低于标准要求;高温下抗拉强度和塑性显著降低,670℃抗拉强度已低于标准外推值;组织严重老化,孪晶消失,除NbC、M_(23)C_(6)等碳化物外,晶内、晶界均不同程度析出了硬脆的σ相,是导致塑、韧性及高温抗拉强度大幅下降的主要原因。

关键词： S30432钢高温长时服役组织 σ相力学性能

Synthesis and characterization of mixing soft-segmented waterborne polyurethane polymer electrolyte with room temperature ionic liquid

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Chinese Chemical Letters 2009年第5期20卷 519-522页

作者： Yue Jiao Li Feng Wu Ren jie chen School of Chemical Engineering and Environment Beijing Institute of Technology Beijing 100081 China National Development Center for High Technology Green Material Beijing 100081 China

Composite polymer electrolytes based on mixing soft-segment waterborne polyurethane （WPU） and 1-butyl-3-methylimidazolium bis[（trifluoromethyl）sulfonyl]imide （BMImTFSI） have been prepared and characterized. The addition of BMImTFSI results in an increase of the ionic conductivity. At high BMImTFSI concentration （BMImTFSI/WPU = 3 in weight ratio）, the ionic conductivity reaches 4.27 × 10^-3 S/cm at 30 ℃. These composite polymer electrolytes exhibit good thermal and electrochemical stability, which are high enough to be applied in lithium batteries.

关键词： Composite polymer electrolytes Ionic liquid Waterborne polyurethane Ionic conductivity 1-Butyl-3-methylimidazoliumbis[(trifluoromethyl) sulfonyl]imide

二维范德瓦耳斯异质结Cs_(3)X_(2)I_(9)/InSe(X=Bi,Sb)的光电性能

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物理学报 2024年第13期73卷 229-237页

作者：熊祥杰钟防张资文陈芳罗婧澜赵宇清朱慧平蒋绍龙湖南科技大学物理与电子科学学院智能传感器与新型传感器材料湖南省重点实验室湘潭411201 格拉斯哥大学亚当史密斯学院格拉斯哥G128QQ 中国科学院微电子研究所硅器件技术重点实验室北京100029 粤港澳大湾区(广东)量子科学中心深圳518045

设计二维半导体范德瓦耳斯异质结是一种实现多功能微电子器件的有效策略.本文构筑了二维钙钛矿Cs_(3)X_(2)I_(9)(X=Bi,Sb)和铟锡InSe的范德瓦耳斯异质结Cs_(3)X_(2)I_(9)/InSe.基于密度泛函理论的第一性原理方法,计算了其几何、电子结... 详细信息

设计二维半导体范德瓦耳斯异质结是一种实现多功能微电子器件的有效策略.本文构筑了二维钙钛矿Cs_(3)X_(2)I_(9)(X=Bi,Sb)和铟锡InSe的范德瓦耳斯异质结Cs_(3)X_(2)I_(9)/InSe.基于密度泛函理论的第一性原理方法,计算了其几何、电子结构、光学性质.研究表明,二维Cs3Bi2I9/InSe和Cs3Sb2I9/InSe异质结为II型能带排列,且带隙分别为1.61 eV和1.19 eV,可见光和紫外光范围内具有较高的吸收系数.基于形变势理论和类氢原子模型的计算,二维Cs_(3)X_(2)I_(9)/InSe异质结显示了较高的电子迁移速率和激子结合能.基于Ⅱ型排列的能带结构和肖克利-奎伊瑟极限(Shockley-Queisser limit),对比研究了光电转换效率.此外,进一步探究了双轴应变对二维异质结Cs_(3)X_(2)I_(9)/InSe光电特性的调控及其规律.上述研究为未来设计高效的二维范德瓦耳斯光电子器件提供了理论依据.

关键词：二维异质结光电转换效率第一性原理计算应变工程

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大型液氦杜瓦结构设计与漏热分析

低温与超导 2024年第2期52卷 97-102页

作者：胡咸军黄天亮张玉建陈杰董文庆中船重工鹏力(南京)超低温技术有限公司南京211100

为了维持较低的液氦蒸发率,对液氦杜瓦的整体结构设计及漏热要求极高。本文建立了以蒸发冷氦气作为冷屏冷源的杜瓦的结构强度设计以及绝热系统设计方法,利用三维软件建模、仿真软件进行热传导、热固耦合仿真分析,对液氦杜瓦的结构强度... 详细信息

为了维持较低的液氦蒸发率,对液氦杜瓦的整体结构设计及漏热要求极高。本文建立了以蒸发冷氦气作为冷屏冷源的杜瓦的结构强度设计以及绝热系统设计方法,利用三维软件建模、仿真软件进行热传导、热固耦合仿真分析,对液氦杜瓦的结构强度、漏热进行了系统分析,实现了容积为4000 L时漏热为1.37 W、日蒸发率为1.15%气冷屏结构的液氦杜瓦,为蒸发氦气为冷屏的大型液氦杜瓦提供了设计思路。

关键词：液氦杜瓦漏热分析日蒸发率爆破管设计热声振荡

miR-155对慢性髓细胞白血病细胞凋亡及热休克蛋白表达的影响

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安徽医科大学学报 2024年第1期59卷 34-39页

作者：任影丽陈治东孙蓓蓓姚杰马凡周强安徽医科大学第二附属医院检验科合肥230601

目的探讨微小RNA-155(miR-155)对慢性髓细胞白血病(CML)细胞凋亡情况和对热休克蛋白(HSP)27、HSP60及HSP70表达的影响。方法采用实时荧光定量逆转录PCR(RT-qPCR)分别检测miR-155在CML耐伊马替尼(IM)细胞株K562-G和CML细胞株K562中的表... 详细信息

目的探讨微小RNA-155(miR-155)对慢性髓细胞白血病(CML)细胞凋亡情况和对热休克蛋白(HSP)27、HSP60及HSP70表达的影响。方法采用实时荧光定量逆转录PCR(RT-qPCR)分别检测miR-155在CML耐伊马替尼(IM)细胞株K562-G和CML细胞株K562中的表达水平。以携带miR-155的慢病毒和阴性对照慢病毒感染K562-G细胞,分别命名为miR-155组和对照组。细胞计数试剂盒8(CCK-8)检测miR-155对耐药细胞增殖的影响。RT-qPCR及蛋白质印迹法(Western blot)检测miR-155对HSP27、HSP60、HSP70表达的影响。流式细胞术检测miR-155组和对照组细胞的凋亡比例。结果与K562细胞相比,K562-G细胞中miR-155呈低表达(P<0.05)。miR-155组细胞的增殖情况与对照组相比从第36 h开始降低(P<0.05)。与对照组相比,miR-155组HSP60、HSP70升高(P<0.05),而HSP27降低(P<0.01)。流式细胞术检测结果显示,miR-155组细胞的凋亡率高于其对照组(P<0.05)。结论miR-155促进CML细胞的凋亡,并使细胞中的HSP60、HSP70表达升高,HSP27表达降低。

关键词： miR-155 慢性髓细胞白血病耐药热休克蛋白细胞增殖凋亡

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Shuttle-run synchronization in mobile ad hoc networks

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Frontiers of physics 2015年第3期10卷 105-112页

作者： sheng-Fei Ma Hong-jie Bi Yong Zou Zong-Hua Liu Shu-Guang Guan Department of Physics East China Normal University Shanghai 200241 China State Key Laboratory of Theoretical Physics Institute of Theoretical Physics Chinese Academy of Sciences Beijing 100190 China

In this work, we study the collective dynamics of phase oscillators in a mobile ad hoc network whose topology changes dynamically. As the network size or the communication radius of individual oscillators increases, the topology of the ad hoc network first undergoes percolation, forming a giant cluster, and then gradually achieves global connectivity. It is shown that oscillator mobility generally enhances the coherence in such networks. Interestingly, we find a new type of phase synchronization/clustering, in which the phases of the oscillators are distributed in a certain narrow range, while the instantaneous frequencies change signs frequently, leading to shuttle-run-like motion of the oscillators in phase space. We conduct a theoretical analysis to explain the mechanism of this synchronization and obtain the critical transition point.

关键词： synchronization phase transition ad hoc network

Atomic Force Microscopy of Surface Reconstructed SrTiO3 Vicinal Substrates for Epitaxial Growth of YBa_(2)Cu_(3)O_(7-δ) Thin Films

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Chinese Physics Letters 1999年第11期16卷 853-855页

作者： HU Wen-fei LI Lin WANG Tian-sheng LIU Wei TAO Hong-jie TIAN Yong-jun chen Ying-fei National Laboratory for Superconductivity Chinese Academy of SciencesBeijing 100080 Institute of Physics Chinese Academy of SciencesBeijing 100080 Department of Material Science Yanshan UniversityQinhuangdao 066004

SrTiO_(3)(001) vicinal substrates of miscut 1°, 3°, and 6° toward the (001) plane were annealed at 800-1000°C in pure flowing O_(2) for 6h and examined by atomic force microscopy. The high temperature annealed vicinal SiTiO_(3)(001) displayed arrays of straight steps and smooth terraces. The step heights vary from about 2 to 6 unit cell depending on the annealing temperatures. At 1000°C, step bunching becomes obvious. The height steps of 1 unit cell are difficult to be observed by our atomic force microscopy. The YBa2Cu3O7-δ thin film grows epitaxially on the step-terrace surface with c-axis orientation by magnetron sputtering in the two-dimensional island mode. Prospect of step-flow growth is being discussed.

关键词： steps straight island

High-performance supercapacitor based on ultralight and elastic three-dimensional carbon foam/reduced graphene/polyaniline nanocomposites

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Chinese Chemical Letters 2019年第6期30卷 1137-1140页

作者： Canwei Peng jie Yu Shouhui chen Li Wang Key Laboratory of Functional Small Organic Molecule Key Laboratory of Chemical BiologyCollege of Chemistry and Chemical Engineering Jiangxi Normal University

A novel supercapacitor based on ultralight and elastic three-dimensional (3D) porous melamine foam (MF)-derived macroporous carbon (3DPMFDMC)/reduced graphene oxide (rGO)/polyaniline (PANI) nanocomposites (denoted as 3DPMFDMC/rGO/PANI) were fabricated. By high temperature carboniza-tion, the commercial MF soaked in GO solution was prepared into ultralight and elastic 3DPMFDMC, the rGO were uniformly distributed into 3DPMFDMC to obtain 3DPMFDMC/rGO, and finally PANI was grown on the 3DPMFDMC/rGO by using in situ chemical oxidation polymerization method. The obtained 3DPMFDMC/rGO/PANI nanocomposites were characterized by SEM, FT-IR and Raman. The results showed the uniform distribution of rGO connected the broken fibers of 3DPMFDMC produced in the high temperature carbonization to improve the electrical conductivity and also enlarged the specific surface area of nanocomposites greatly. Lots of PANI were vertically arrayed on the surface of 3DPMFDMC/rGO. 3DPMFDMC/rGO/PANI exhibited a rapid electron/mass transport. Owing to its special structures and nanocomposites, the supercapacitor showed good electrical performance with a specific capacitance of 1870 F/g at the current density of 1 A/g. Moreover, the specific capacitance remained 95.4%after 1000 charging/discharging cycles at a current density of 5 A/g.

关键词： Polyaniline Supercapacitors Melamine foam Macroporous carbon Reduced graphene oxide