检索结果-南通市图书馆

Journal of Mountain Science 2023年第5期20卷 1307-1315页

作者： ZHAN qing-hua FU Zhi-hao ZHOU Ya-dong YAN Xue wang qing-feng School of Life Sciences Nanchang UniversityNanchang 330031China Wuhan Botanical Garden/Core Botanical Gardens Chinese Academy of SciencesWuhan 430074China Sino-Africa Joint Research Center(SAJOREC) Chinese Academy of SciencesWuhan 430074China

Field surveys and empirical integrated methods are commonly used in the ecological research to understand the altitudinal pattern of plant diversity of mountains.However,few studies have compared the differences between the two methods on the same scale.Here,we addressed and compared the altitudinal patterns of species richness(SR),phylogenetic diversity(PD),the standardized effect size of phylogenetic diversity(PDses)and mean phylogenetic distance(MPDses)of about 580 angiosperms growing on Mount Kenya from two independent datasets:one is based on our several times field surveys in this mountain and another one is based on empirical data integrated from literatures.We found that the altitudinal diversity patterns of field surveys dataset were consistent with the empirical integrated dataset.Both SR and PD showed hump-shaped patterns along the altitude,and both PDses and MPDses showed monotonically decreasing patterns along the altitude.The ratio of diversity between field surveys dataset and empirical integrated dataset were gradually increase along the altitude.Our research provides new insight for understanding the altitudinal diversity patterns of plants of a tropical mountain.

关键词： Mount Kenya Africa Surveys Interpolation method Taxonomic Phylogenetic

Effect of Tempering Temperature on Microstructure and Mechanical Properties of Steel Containing Ni of 9%

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2011年第5期18卷 47-51,58页

作者： ZHAO Xi-qing PAN Tao wang qing-feng SU Hang YANG Cai-fu YANG qing-xiang State Key Laboratory of Metastable Materials Science and Technology Yanshan UniversityQinhuangdao066004HebeiChina Division of Structural Material Research Central Iron and Steel Research InstituteBeijing 100081China

Mechanical properties of quenching,intercritical quenching and tempering （QLT） treated steel containing Ni of 9% were evaluated from specimens subject to various tempering temperatures. The detailed microstructures of steel containing Ni of 9% at different tempering temperatures were observed by optical microscope （OM） and transmission electron microscope （TEM）. The volume fraction of austenite was estimated by XRD. The results show that high strength and cryogenic toughness of steel containing Ni of 9% are obtained when the tempering temperature are between 540 and 580 ℃. The microstructure keeps the dual phase lamellar structure after the intercritical quenching and there is cementite created in the Ni-rich constituents when tempering temperature is 540 ℃. When tempering temperatures are between 560 and 580 ℃,the reversed austenites （γ′） grow up and the dual phase lamellar structure is not clear. The γ′ becomes instable at 600 ℃. When tempered at temperature ranging from 500 to 520 ℃,the increase of dislocation density in the lamellar matrix makes both tensile strength and yield strength decrease. When tempered at 540 ℃ and higher temperature,the yield strength decreases continuously because the C and alloying elements in the matrix are absorbed by the cementite and the γ′,so the yield ratio is decreased by the γ′. There are two toughness mechanisms at different tempering temperatures. One is that the precipitation of cementite absorbs the carbon in the steel which plays a major role in improving cryogenic toughness at lower temperature. Another is that the γ′ and the purified matrix become major role at higher tempering temperature. When the tempering temperature is 600 ℃,the stability of γ′ is decreased quickly,even the transformation takes place at room temperature,which results in a sharp decrease of Charpy-V impact energy at 77 K. The tempering temperature range is enlarged by the special distribution of cementite and the lamellar structure.

关键词： steel containing Ni of 9% tempering temperature cementite reversed austenite cryogenic toughness

Effect of Niobium on Dynamic Recrystallization Behavior of 5%Ni Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2013年第6期20卷 38-44页

作者： LEI Xiao-rong DING qing-feng CHEN Yuan-yuan RUI Xiao-long LI Shu-rui wang qing-feng State Key Laboratory of Metastable Materials Science and Technology Yanshan University Research and Development Center Wuhan Iron and Steel Company

The single-pass hot compressions of two 5%Ni steels with and without niobium addition at different temperatures of 800-1 150℃and strain rates of 0.01-1s-1 were performed by using a Gleeble-3500 thermal simulator and the effect of niobium on the dynamic recrystallization （ DRX ） behavior was analyzed.The results showed that the niobium addition of 0.04% can retard DRX in 5%Ni steel significantly by increasing the activation energy for DRX from 394 to 462kJ / mol.The critical strain required for starting DRX in 5%Ni steel was increased by 0.04-0.10 with niobium addition when the steel was deformed at a strain rate of 0.01s-1 and temperatures varied from 950 to 1 000℃.The critical temperature required for starting DRX in 5%Ni steel was also increased from 1 000 to 1 050℃ with niobium addition when the steel was deformed at a strain rate of 0.1s-1 .Such a retarded DRX occurring in Nb-added 5%Ni steel can be attributed to the pinning effect of precipitates containing niobium.

关键词： 5%Ni steel dynamic recrystallization niobium precipitation pinning effect

Kinetic Model of ε-Cu Particle Dissolution in Welding-Induced HAZ of Copper-Containing Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2008年第5期15卷 66-69页

作者： wang qing-feng CHAI feng CAI Jian-wei PAN Tao SU Hang State Key Laboratory of Metastable Materials Technology and Science Yanshan University Qinhuangdao 066004 Hebei China Division of Structural Material Research Central Iron and Steel Research Institute Beijing 100081 China College of Materials Science and Engineering Shanghai Jiaotong University Shanghai 200030 China

The kinetics of ε-Cu particle dissolution in the matrix of heat affected zone （HAZ） during welding of a copper-containing steel was determined by assembling the welding temperature-time program into a modified Whelan＇s solution. The particle dissolution dependence on the degree of ＂superheating＂ above the equilibrium transformation is demonstrated from the model. In terms of volume fraction of particle dissolution, the HAZ may he classified into three zones, including the undissolving zone, the partially dissolving zone, and the completely dissolving zone, respectively. The numerical solution was in good agreement with the experimental examination finding. The results of model can be used to quantitatively map the ε-Cu dissolution zone dependence on the peak temperature of welding thermal cycles and understand the evolution of this transformation during welding.

关键词： ε-Cu particle dissolution kinetics welding steel

Phenotypic plasticity of floral traits and pollination adaption in an alpine plant Pedicularis siphonantha D. Don when transplanted from higher to lower elevation in Eastern Himalaya

在线全文

学校读者我要写书评

暂无评论

Journal of Mountain Science 2017年第10期14卷 1995-2002页

作者： DAI Wen-Kui AMBOKA Grace Mercy KADIORI Edwin Luguba wang qing-feng YANG Chun-feng Key Laboratory of Aquatic Botany and Watershed Ecology Wuhan Botanical Garden Chinese Academy of Sciences College of Life Sciences University of Chinese Academy of Sciences

Phenotypic plasticity and/or pollinatormediated selection may be responsible for the changes in floral traits of plants when they are forced to live in new conditions. Although the two events could be independent, we hypothesized that phenotypic plasticity in floral traits might help to coordinate plant-pollinator interactions and enhance plant reproductive success in changing habitats. To test this hypothesis, we investigated floral traits and pollination on three natural populations of a lousewort(Pedicularis siphonantha) ranging at different elevations, as well as two downward transplanted populations in Shangeri-La County and Deqin County, northwest Yunnan, China. The results indicated that floral traits, i.e. phenology, longevity,display size, corolla tube length and pollen production differed significantly among populations. Moreover,or the two transplanted populations, floral traits diverged from their original populations, but converged to their host populations. Although the phenotypic plasticity in floral traits might be a rapid response to abiotic factor such as warmer environment, the changes in floral traits were found to be well adapted to pollination environment of the host population. Compared with plants of their original habitats in higher elevation, the transplanted individuals advanced flowering time, shortened flower longevity, reduced floral display size and pollen production, received higher visiting frequency and yielded more seeds. These findings suggested that phenotypic plasticity of floral traits might help plants adjust their resource allocation strategy between preand post-pollination stages in response to harsh or temperate conditions, which might correspondingly meet a pollinator-poor or hyphen rich environment.This would be beneficial for the widely-distributed species to adapt to various environmental changes.

关键词：表型可塑性高山植物花器性状马先蒿属传粉者低海拔移植喜马拉雅

中国式现代化视域下强化战略思维的内在逻辑和实践路径

在线全文

学校读者我要写书评

暂无评论

扬州教育学院学报 2024年第2期42卷 75-80页

作者：王青峰湖北省社会科学院湖北武汉430077

作为一种立足现实、高瞻远瞩的掌握事物发展总体方向的思维能力,战略思维成为中国共产党准确理解与全面推动中国式现代化的哲学方法论。从党的百年奋斗历程来看,坚持战略思维这一哲学方法论蕴含于中国共产党团结带领中国人民逐步探索社... 详细信息

作为一种立足现实、高瞻远瞩的掌握事物发展总体方向的思维能力,战略思维成为中国共产党准确理解与全面推动中国式现代化的哲学方法论。从党的百年奋斗历程来看,坚持战略思维这一哲学方法论蕴含于中国共产党团结带领中国人民逐步探索社会主义现代化建设道路,推进中国式现代化的过程之中。推进中国式现代化是一项复杂的系统工程,涉及到党和国家事业的各个方面,需要统揽全局、眼光放远,正确运用战略思维,推动中国式现代化巨轮行稳致远。

关键词：战略思维中国式现代化内在逻辑实践路径

在线全文

学校读者我要写书评

暂无评论

地黄环烯醚萜氧化酶基因的克隆与功能分析

中国中药杂志 2024年第11期49卷 2897-2905页

作者：宋词高俊鸽杨雅贺丁宁王丰青袁媛河南农业大学农学院河南郑州450002 中国中医科学院中药资源中心北京100700

地黄为我国传统的常用大宗中药材,具有清热凉血、养阴生津之功效。环烯醚萜苷是地黄药材的主要活性成分,环烯醚萜氧化酶是环烯醚萜苷生物合成途径的关键限速酶。该研究基于转录组数据,筛选到1条环烯醚萜氧化酶基因RgIO,对其进行了系统... 详细信息

地黄为我国传统的常用大宗中药材,具有清热凉血、养阴生津之功效。环烯醚萜苷是地黄药材的主要活性成分,环烯醚萜氧化酶是环烯醚萜苷生物合成途径的关键限速酶。该研究基于转录组数据,筛选到1条环烯醚萜氧化酶基因RgIO,对其进行了系统的生物信息学、表达特性和亚细胞定位分析。结果表明,RgIO的编码区为1536 bp,编码511个氨基酸,相对分子质量58258.01。RgIO的蛋白序列包含细胞色素P450氧化酶的保守结构域和基序,与列当科3个植物独脚金、黄独脚金和大花胡麻草的同源蛋白序列一致性最高,与长春花CrIO的序列一致性也高达77.28%。RgIO在地黄的叶中特异性高表达,而且响应茉莉酸甲酯(MeJA)的诱导,MeJA处理3、6 h,在叶和块根中其表达量分别增加了3.15、1.3倍。亚细胞定位结果显示Rg IO分布在内质网上。利用根癌农杆菌介导法在地黄叶片中瞬时表达Rg IO,梓醇的含量较瞬时表达空载体的对照增加了0.82倍。该研究为地黄梓醇的分子调控和生物合成提供了关键的靶基因,也为完整解析地黄梓醇的生物合成途径奠定了基础。

关键词：地黄环烯醚萜氧化酶基因克隆表达亚细胞定位

Effect of Martensite Morphology on Impact Toughness of Ultra-High Strength 25CrMo48V Steel Seamless Tube Quenched at Different Temperatures

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2013年第2期20卷 62-67页

作者： ZHANG Chuan-you wang qing-feng KONG Jin-li XIE Guo-zhu wang Ming-zhi ZHANG Fu-cheng State Key Laboratory of Metastable Materials Science and Technology Yanshan University National Engineering Research Center for Equipment and Technology of Cold Strip Rolling Yanshan University

A 25CrMo48V steel for ultra-deep oil/gas well casings was quenched at 900-1 200 ℃ and tempered at 650 ℃. The lath martensitic structures were characterized by optical microscope （OM）, field emission scanning electron microscopy （FESEM）, electron backscattering diffraction （EBSD） and transmission electron microscopy （TEM）, and the transverse impact energy at 0 ℃ was measured from the as-quenched and tempered specimens. The results show that with the quenching temperature decreased, the prior austenite grain, martensitic packet and block are refined, while the lath width seems to remain unchanged. The enhancement of impact toughness with the decreasing quenching temperature can be attributed to refinement of the martensitic structure with high-angle boundaries, and the block is the minimum structure unit controlling impact toughness. The transverse impact energy [ECVN （0 ℃） ≥100 J] required for seamless casings with ultra-high strength （Rp0.2≥932 MPa） has been finally achieved with the experimental steel quenched at 900-1 000 ℃ and tempered at 650 ℃.

关键词： seamless steel tube lath martensitic morphology toughness

Physical Simulation and Experimental Examination of ε-Cu Particles Dissolution Evolution During Welding of Copper Precipitation Strengthening Steel

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research(International) 2007年第6期14卷 58-62页

作者： wang qing-feng SHANG Cheng-jia CHEN Da-wei CAI Jian-wei CHEN Wei-chang State Key Laboratory of Metastable Materials Science and Technology Yanshan University Qinhuangdao 066004 Hebei China Department of Materials Physics University of Science and Technology Beijing Beijing 100083 China Dynamic Systems Inc Poestenkill NY12140 USA DSI-YSU Joint Laboratory of Physical Simulation on Materials Processing Yanshan University Qinhuangdao 066004 Hebei China

The kinetics of ε-Cu particles dissolution in the matrix during welding of a copper-precipitation strengthening steel was determined by a combination of GleebleTM physical simulation, TEM examination and hardness meas urement. The ε-Cu particles underwent a coarsening and part dissolution and then complete dissolution reaction as the peak temperature increased from 750 to 1 000℃, which resulted in the decrease in the number density of ε-Cu particles and hardness in the heat affected zone （HAZ）. The results can be used to understand the evolution of this transformation and a softening behavior of the HAZ during welding of this type of steel.

关键词： ε-Cu particle dissolution hardness kinetics steel welding physical simulation

不同能量饲料对贵州黑山羊生长性能、屠宰性能、肉质性状、氨基酸及脂肪酸含量的影响

在线全文

学校读者我要写书评

暂无评论

饲料研究 2024年第7期47卷 1-6页

作者：杨洋王清峰袁超粟朝芝肖文贵州省畜牧兽医研究所贵州贵阳550025 贵州大学高原山地动物遗传育种与繁殖教育部重点实验室贵州贵阳550025

试验旨在探究不同能量饲料对贵州黑山羊生长性能、屠宰性能、肉质性状及肌肉中氨基酸、脂肪酸含量的影响。选取生长状况基本一致体重为(21.12±1.25) kg的6月龄贵州黑山羊公羊45只,随机分为3组,每组3个重复,每个重复5只。玉米组、大麦... 详细信息

试验旨在探究不同能量饲料对贵州黑山羊生长性能、屠宰性能、肉质性状及肌肉中氨基酸、脂肪酸含量的影响。选取生长状况基本一致体重为(21.12±1.25) kg的6月龄贵州黑山羊公羊45只,随机分为3组,每组3个重复,每个重复5只。玉米组、大麦组、小麦组分别饲喂以玉米、大麦和小麦为主要能量饲料配方的混合饲粮。预试期7 d,正式试验期90 d。结果表明:大麦组平均日增重达到180.56 g,显著高于其他两组(P<0.05),玉米组和大麦组屠宰率均显著高于小麦组(P<0.05),玉米组滴水损失、熟肉率以及干物质含量均最高,小麦组粗脂肪含量最高。各试验组羊肉中均检出16种氨基酸,包含7种必需氨基酸和9种非必需氨基酸,大麦组和小麦组非必需氨基酸含量显著高于玉米组(P<0.05)。各试验组羊肉中共检测出37种脂肪酸,其中检测出17种饱和脂肪酸,9种单不饱和脂肪酸,11种多不饱和脂肪酸。小麦组饱和脂肪酸和单不饱和脂肪酸的含量最高,大麦组多不饱和脂肪酸的含量显著高于玉米组和小麦组(P<0.05)。研究表明,大麦能够提升贵州黑山羊生长性能和屠宰性能,且肉品质相对较好,可作为主要能量饲料使用。

关键词：贵州黑山羊生长性能屠宰性能肉质性状氨基酸脂肪酸

维普期刊数据库博看期刊