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A Novel Multiphase Stainless Steel with Ultra-Low Yield Ratio and High Ductility 被引量:1
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作者 Menghao Liu Cuiwei Du +1 位作者 Yuewu Li Xiaogang Li 《Acta Metallurgica Sinica(English Letters)》 SCIE EI CAS CSCD 2024年第10期1777-1784,共8页
This study focuses on developing a novel multiphase stainless steel with enhanced ductility and an ultralow yield ratio achieved through solid-solution treatment.The steel exhibits remarkable mechanical properties:a t... This study focuses on developing a novel multiphase stainless steel with enhanced ductility and an ultralow yield ratio achieved through solid-solution treatment.The steel exhibits remarkable mechanical properties:a tensile strength of approximately 1114 MPa,an ultralow yield ratio of 0.36,exceptional uniform elongation of approximately 17.48%,and total elongation of approximately 21.73%.The remarkable ductility of the steel can be attributed to the transformation-induced plasticity(TRIP)effect observed in the retained austenite,while its exceptional strength results from the combined effects of TRIP and the martensite phase. 展开更多
关键词 Stainless steels Metastable phases low yield ratio Martensitic phase transformation
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Low cycle fatigue estimation of low yield point steel
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作者 LI Chen and DING Fulian Research Institute,Baoshan Iron & Steel Co.,Ltd.,Shanghai 201900,China 《Baosteel Technical Research》 CAS 2010年第S1期123-,共1页
With the development of technology for earthquake resistant,the research of the low yield point(LYP) steel which used for the fabrication of energy dissipation damper were paid more and more attention.The common studi... With the development of technology for earthquake resistant,the research of the low yield point(LYP) steel which used for the fabrication of energy dissipation damper were paid more and more attention.The common studies of the low yield point steel is mainly about the performance with constant amplitude and constant frequency.The low cycle fatigue properties of low yield piont steel were studied by series of test with continuous varying amplitude and varying frequency with the materials testing system by us.The test results showed that low yield point steel of Baosteel have excellent low cycle fatigue properties,which meet the requirement for steel used for the fabrication of energy dissipation damper completely.The low cycle fatigue performance of low yield point steel of Baosteel mainly depended on the amplitude in test.And the effect of varying frequency for the low yield point steel was more less than varying amplitude. 展开更多
关键词 low cycle fatigue low yield point steel continuous varying amplitude and varying frequency high strain
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Research of an Appropriate Sowing Quantity of Double-cropping Machine-transplanted Rice in Low and Medium Yielding District of Southern Jiangxi Province
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作者 钟珺 胡启锋 +4 位作者 李云 黎为兵 连垚 张朝阳 虞新华 《Agricultural Science & Technology》 CAS 2016年第3期526-529,543,共5页
[Objective] The aim was to research the appropriate seeding quantities of double-season machine-transplanted rice in middle and low-yielding district of southern Jiangxi Province. [Method] The research set five differ... [Objective] The aim was to research the appropriate seeding quantities of double-season machine-transplanted rice in middle and low-yielding district of southern Jiangxi Province. [Method] The research set five different seeding quantities treatments, and compared with conventional seedling treatment, and the appropriate seeding quantities of double season machine-transplanted rice in middle and lowyielding district of southern Jiangxi Province was discussed. [Result] The yields were highest when the seeding quantity was 70 g per tray of early rice by mechanical transplanting and 60 g per tray of late rice. The yield of early rice by mechanical transplanting showed significantly positive correlation with the number of productive ear and the number of seed per ear, and late rice yield showed significant correlation with the number of productive ear by mechanical transplanting. It is key for improving high yields by guaranteeing the number of productive ear. [Conclusion] The issue of proper sowing quantity should be taken into consideration for double-cropping rice in the region, which is crucial for high yields. 展开更多
关键词 Sowing quantity Double-cropping rice Machine-transplanted Rice low and medium yielding farmlands
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Investigation and solution of low yield problem for phase change memory with lateral fully-confined structure
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作者 周亚玲 王晓峰 +2 位作者 付英春 王晓东 杨富华 《Journal of Semiconductors》 EI CAS CSCD 2016年第8期63-66,共4页
This paper mainly focuses on solving the low yield problem for lateral phase change random access memory with a fully confined phase change material node. Improper over-etching and bad step-coverage of physical vapor ... This paper mainly focuses on solving the low yield problem for lateral phase change random access memory with a fully confined phase change material node. Improper over-etching and bad step-coverage of physical vapor deposition were the main reasons for the poor contact quality, which leads to the low yield problem. Process improvement was carried out to better control over-etching within 10 nm. Atomic layer deposition process was used to replace physical vapor deposition to guarantee good step coverage. Contrasting cross-sectional photos taken by scanning electron microscopy showed great improvement in contact quality. The atom layer deposition process was demonstrated to have good prospects in nano-contact for phase change memory application. 展开更多
关键词 low yield over-etching fully confined NANOCONTACT phase change random access memory
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Potential promoted productivity and spatial patterns of medium-and low-yield cropland land in China 被引量:9
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作者 闫慧敏 冀咏赞 +3 位作者 刘纪远 刘芳 胡云锋 匡文慧 《Journal of Geographical Sciences》 SCIE CSCD 2016年第3期259-271,共13页
With a continuously increasing population and better food consumption levels, im- proving the efficiency of arable land use and increasing its productivity have become funda- mental strategies to meet the growing food... With a continuously increasing population and better food consumption levels, im- proving the efficiency of arable land use and increasing its productivity have become funda- mental strategies to meet the growing food security needs in China. A spatial distribution map of medium- and low-yield cropland is necessary to implement plans for cropland improvement In this study, we developed a new method to identify high-, medium-, and low-yield cropland from Moderate Resolution Imaging Spectroradiometer (MODIS) data at a spatial resolution of 500 m. The method could be used to reflect the regional heterogeneity of cropland productiv- ity because the classification standard was based on the regionalization of cropping systems in China. The results showed that the proportion of high-, medium-, and low-yield cropland in China was 21%, 39%, and 40%, respectively. About 75% of the low-yield cropland was lo- cated in hilly and mountainous areas, and about 53% of the high-yield cropland was located in plain areas. The five provinces with the largest area of high-yield cropland were all located in the Huang-Huai-Hai region, and the area amounted to 42% of the national high-yield cropland area. Meanwhile, the proportion of high-yield cropland was lower than 15% in Hei- Iongjiang, Sichuan, and Inner Mongolia, which had the largest area allocated to cropland in China. If all the medium-yield cropland could be improved to the productive level of high-yield cropland and the low-yield cropland could be improved to the level of medium-yield cropland, the total productivity of the land would increase 19% and 24%, respectively. 展开更多
关键词 food security light use efficiency model cropland productivity high- medium- and low-yield crop-land potential productivity
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Effects of Low Light on Agronomic and Physiological Characteristics of Rice Including Grain Yield and Quality 被引量:19
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作者 LIU Qi-hua WU Xiu +2 位作者 CHEN Bo-cong MA Jia-qing GAO Jie 《Rice science》 SCIE 2014年第5期243-251,共9页
Light intensity is one of the most important environmental factors that determine the basic characteristics of rice development. However, continuously cloudy weather or rainfall, especially during the grain-filling st... Light intensity is one of the most important environmental factors that determine the basic characteristics of rice development. However, continuously cloudy weather or rainfall, especially during the grain-filling stage, induces a significant loss in yield and results in poor grain quality. Stress caused by low light often creates severe meteorological disasters in some rice-growing regions worldwide. This review was based on our previous research and related research regarding the effects of low light on rice growth, yield and quality as well as the formation of grain, and mainly reviewed the physiological metabolism of rice plants, including characteristics of photosynthesis, activities of antioxidant enzymes in rice leaves and key enzymes involved in starch synthesis in grains, as well as the translocations of carbohydrate and nitrogen. These characteristics include various grain yield and rice quality components (milling and appearance as well as cooking, eating and nutritional qualities) under different rates of shading imposed at the vegetative or reproductive stages of rice plants. Furthermore, we discussed why grain yield and quality are reduced under the low light environment. Next, we summarized the need for future research that emphasizes methods can effectively improve rice grain yield and quality under low light stress. These research findings can provide a beneficial reference for rice cultivation management and breeding program in low light environments. 展开更多
关键词 grain quality grain yield physiological characteristic RICE low light agronomic characteristic
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A New Type of Multielements-Doped,Carbon-based Materials Characterized by High-thermoconductiv-ity,Low Chemical Sputtering,Low RES Yield and Exposure to Plasma
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作者 许增裕 刘翔 +4 位作者 谌继明 王明旭 宋进仁 翟更太 李承新 《Plasma Science and Technology》 SCIE EI CAS CSCD 2002年第3期1311-1317,共7页
Low-Z materials, such as carbon-based materials and Be, are major plasma-facing material (PFM) for current, even in future fusion devices. In this paper, a new type of multielement-doped carbon-based materials develop... Low-Z materials, such as carbon-based materials and Be, are major plasma-facing material (PFM) for current, even in future fusion devices. In this paper, a new type of multielement-doped carbon-based materials developed are presented along with experimental re-sults of their properties. The results indicate a decrease in chemical sputtering yield by one order of magnitude, a decrease in both thermal shock resistance and radiation-enhanced sublimation, an evidently lower temperature desorption spectrum, and combined properties of exposing to plasma. 展开更多
关键词 than GBS RES A New Type of Multielements-Doped Carbon-based Materials Characterized by High-thermoconductiv-ity low Chemical Sputtering low RES yield and Exposure to Plasma
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The Type of Low-yielding Fields,Using Direction and Land Fertility Building Measures in Suiping County
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作者 Jiuyi HU 《Asian Agricultural Research》 2014年第11期81-82,86,共3页
Using the evaluation indicator system for arable land fertility in Suiping County,this paper analyzes some factors influencing agricultural production,such as physical and chemical properties of soil,site conditions,s... Using the evaluation indicator system for arable land fertility in Suiping County,this paper analyzes some factors influencing agricultural production,such as physical and chemical properties of soil,site conditions,soil management,and soil nutrients concerning various types of low-yielding fields in the county. In accordance with the dominant soil constraint factors and main direction of improvement,the lowyielding fields in the county are divided into four types: irrigation improvement type,waterlogging drainage type,barren soil fertilization and barrier layer type. Finally this paper offers specific guidance on the construction of arable land. 展开更多
关键词 TYPE of low-yielding FIELDS USING direction LAND f
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Actuality and Improvement Measures of Mediumand Low-yielding Farmland in Liaoning Province
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作者 Song Dan 《Meteorological and Environmental Research》 CAS 2015年第10期30-33,共4页
In order to improve the quality of cultivated land in Liaoning Province in the light of local conditions, medium- and low-yielding farmland in Liaoning Province are divided into various zones according to characterist... In order to improve the quality of cultivated land in Liaoning Province in the light of local conditions, medium- and low-yielding farmland in Liaoning Province are divided into various zones according to characteristics of the terrain, and the practical and feasible improvement measures are put forward based on the current situation and main existing problems in the medium- and low-yielding farmland in different areas, 展开更多
关键词 Medium- and low-yielding farmland Current situation Improvement measures China
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灌浆前期低温弱光复合处理对水稻产量和品质的影响 被引量:2
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作者 胡雅杰 郭靖豪 +7 位作者 丛舒敏 蔡沁 徐益 孙亮 郭保卫 邢志鹏 杨文飞 张洪程 《作物学报》 北大核心 2025年第2期405-417,共13页
以软米粳稻南粳9108和常规粳稻淮稻5号为供试材料,通过人工气候室设置梯度温度模拟水稻灌浆前期(齐穗至穗后20d)温度动态递减变化,设置灌浆前期动态低温和低温弱光处理,并以室外温光作为对照(CK),研究灌浆前期低温弱光对水稻产量及其构... 以软米粳稻南粳9108和常规粳稻淮稻5号为供试材料,通过人工气候室设置梯度温度模拟水稻灌浆前期(齐穗至穗后20d)温度动态递减变化,设置灌浆前期动态低温和低温弱光处理,并以室外温光作为对照(CK),研究灌浆前期低温弱光对水稻产量及其构成、干物质生产和稻米品质的影响。结果表明:与CK相比,灌浆前期低温和低温弱光处理均降低水稻产量,低温弱光处理减产显著。灌浆前期低温弱光处理降低结实率和千粒重导致减产;低温处理降低结实率,而千粒重有所增加。与CK相比,灌浆前期低温和低温弱光处理均降低水稻成熟期干物质重和穗部干重,叶和茎鞘干物质积累量较高;倒一叶、倒二叶和倒三叶SPAD值均呈上升趋势,表现为低温弱光>低温>CK;剑叶的过氧化氢酶(CAT)、过氧化物酶(POD)和超氧化物歧化酶(SOD)活性呈先增加后降低趋势,抗坏血酸过氧化物酶(APX)活性呈增加,丙二醛(MDA)含量和H_(2)O_(2)含量较高。就稻米品质而言,与CK相比,灌浆前期低温处理下稻米加工品质和外观品质变优,而低温弱光处理下稻米加工品质变劣。与CK相比,灌浆前期低温处理下直链淀粉含量增加,胶稠度下降,蛋白质含量降低,食味值降低;而低温弱光处理下直链淀粉含量降低,胶稠度下降,蛋白质含量增加,食味值降低。因此,灌浆前期低温和低温弱光均降低稻米食味品质。 展开更多
关键词 水稻 灌浆前期 低温弱光 产量 品质
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LYP波纹双钢板混凝土组合剪力墙抗震性能研究 被引量:1
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作者 袁朝庆 李国洋 +2 位作者 房宽光 张浩 李月 《河北工程大学学报(自然科学版)》 2025年第3期15-22,共8页
为研究低屈服点波纹双钢板混凝土组合剪力墙抗震性能,运用ABAQUS构建有限元模型。以钢板形式(波纹钢板和平钢板)、钢材强度等级(低屈服点钢材和普通钢材)为主要参数进行对比研究,结果表明,波纹钢板试件相比平钢板试件屈服荷载最高提升了... 为研究低屈服点波纹双钢板混凝土组合剪力墙抗震性能,运用ABAQUS构建有限元模型。以钢板形式(波纹钢板和平钢板)、钢材强度等级(低屈服点钢材和普通钢材)为主要参数进行对比研究,结果表明,波纹钢板试件相比平钢板试件屈服荷载最高提升了11.28%,峰值荷载最高提升了11.29%,延性最高提升了18.68%,并且波纹钢板试件的刚度退化较为平缓,耗能能力更强,抗震性能更优;低屈服点钢材试件相比普通钢材试件,虽然更早达到屈服,承载能力有一定下降,但延性得到极大提升,最高提升67.63%,最低提升44.22%,耗能表现更为优异,抗震性能更好。结构的改变和材料的改变均能提高试件的抗震性能,且两者结合更能使试件的抗震性能得到更大提升。 展开更多
关键词 波纹钢板 低屈服点钢材 组合剪力墙 抗震性能
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LYP160低屈服点波纹双钢板混凝土组合剪力墙抗震性能分析
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作者 袁朝庆 李月 +2 位作者 李国洋 张浩 计静 《河北工业科技》 2025年第2期137-145,共9页
为了更好地提升双钢板混凝土组合剪力墙的抗震性能,将新型LYP160低屈服点波纹双钢板替代平钢板应用于组合剪力墙结构,并以混凝土强度(C30、C40、C50和C60)、中低剪跨比(2.0、1.5和1.0)为主要参数,设计了12组试件,其中普通钢材试件、低... 为了更好地提升双钢板混凝土组合剪力墙的抗震性能,将新型LYP160低屈服点波纹双钢板替代平钢板应用于组合剪力墙结构,并以混凝土强度(C30、C40、C50和C60)、中低剪跨比(2.0、1.5和1.0)为主要参数,设计了12组试件,其中普通钢材试件、低屈服点钢材试件各6组。利用有限元软件建立新型LYP160低屈服点波纹双钢板组合剪力墙结构模型,通过绘制滞回曲线和骨架曲线,对12组试件进行承载能力和延性、刚度退化、耗能能力等抗震性能分析。结果表明:1)随着混凝土强度的增大,普通钢材试件和低屈服点钢材试件承载能力提高,延性有一定降低,耗能能力基本无变化,并且在相同混凝土强度下,低屈服点钢材延性比普通钢材延性好;2)随着剪跨比的减小,普通钢材试件和低屈服点钢材试件承载能力提升,延性略有下降,并且在相同剪跨比下,低屈服点钢材比普通钢材的延性最大提升70.83%。研究证明了LYP160低屈服点钢材波纹双钢板混凝土组合剪力墙的承载能力、延性、刚度退化、耗能能力相较于普通试件均有显著提升,具有良好的抗震性能,并可为LYP160低屈服点钢材波纹双钢板混凝土组合剪力墙的应用提供理论参考。 展开更多
关键词 复合结构 波纹钢板 组合剪力墙 LYP160低屈服点钢材 抗震性能
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基于文献计量学分析我国中低产田改良研究态势
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作者 马星竹 郝小雨 +3 位作者 郑雨 赵月 姬景红 刘双全 《黑龙江农业科学》 2025年第1期106-112,共7页
为全面把握我国中低产田改良领域的发展现状和动态,从而促进中低产田土壤改良和耕地保育,以中国CNKI数据库中检索到的中低产田文献为研究对象,运用文献计量学方法收集和分析该领域文献的发文量、涉及学科、文章发表情况、文献来源、所... 为全面把握我国中低产田改良领域的发展现状和动态,从而促进中低产田土壤改良和耕地保育,以中国CNKI数据库中检索到的中低产田文献为研究对象,运用文献计量学方法收集和分析该领域文献的发文量、涉及学科、文章发表情况、文献来源、所属机构和关键词情况,对我国中低产田研究的现状和发展趋势进行了综述,揭示了该领域关注焦点和研究热点。结果表明,我国中低产田改良领域的研究起步于20世纪80年代,截止2024年总计发表920篇学术文章和15篇学位论文;不同年份发表的学术文章数量从整体上看呈起伏状,3个峰值的阶段分别为1991-1992年、1995-1997年及2012-2014年;学术文章涉及的前6个学科分别为农业基础科学、农艺学、农业经济、农作物、自然地理学和测绘学以及农业工程;研究开始较早的是辽宁、广西以及北京等的研究机构,发表文章排在前三的省份分别是新疆、江苏、辽宁和河北。整体文献中核心期刊比例不高,需加强深入研究。通过关键词聚类分析和共现分析,该领域研究主要集中在分类、改良措施、评价以及作物产量等方面。中低产田改良培肥与国家粮食安全密切相关,分析其成因、种类划分、评价方法以及改良利用等诸多方面,农艺与工程相结合是我国中低产田改良的重要途径,集成、配套其他相关技术,最终实现土壤障碍因素消减、土壤肥力提高以及耕地综合生产能力提升。 展开更多
关键词 中低产田 改良 培肥 文献计量学
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播期和萌发期冷处理对不同耐低温性大豆生态性状的影响
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作者 孙晓环 陈造业 +5 位作者 白艳凤 孙国宏 王燕平 宗春美 王晓梅 杜维广 《大豆科学》 北大核心 2025年第1期61-71,共11页
为给选育萌发期耐低温大豆品种和农民“适时早播”种植大豆提供理论依据,本研究首先以相对发芽率和相对正常苗率为指标,综合评价了169份东北大豆种质资源萌发期的耐低温(6℃)能力,从中筛选出10份耐冷型(T)、8份中间型(M)和9份敏感型(S)... 为给选育萌发期耐低温大豆品种和农民“适时早播”种植大豆提供理论依据,本研究首先以相对发芽率和相对正常苗率为指标,综合评价了169份东北大豆种质资源萌发期的耐低温(6℃)能力,从中筛选出10份耐冷型(T)、8份中间型(M)和9份敏感型(S)代表性大豆资源进行田间试验,研究了早播(K)、正常(CK)和晚播(P)等3个播期和萌发期冷处理(N)对不同耐低温类型大豆生态性状的影响。结果表明:随播期推迟,整体上大豆各生育阶段缩短和活动积温减少,有效分枝数从2.2个降低到1.1个,粗蛋白含量从38.8%降低到38.0%,蛋脂总量从60.9%降低到59.0%,同时晚播(P)时单株有效荚数和粒重显著降低,但是早播(K)时大豆单株产量与CK无明显差异;不同耐低温型大豆种质之间各性状随播期的变化规律基本相同,但是存在一些差异;耐冷型(T)大豆具有更高的有效分枝数、蛋白质含量与蛋脂总量(T>M>S)以及单株有效荚数;生育期和积温无明显变化时,大豆萌发期6℃处理后,大豆的花荚脱落率下降5.8%,有效分枝数和单株有效荚数均显著增加,单株粒重增加2.3 g,有增产效应。结果说明,选育萌发期耐冷型大豆并适时早播,有利于改善大豆品质,增加有效分枝数,同时发现萌发期冷胁迫能影响大豆后期生长发育且具有增产效应。 展开更多
关键词 种质资源 大豆 萌发期 耐低温 播期 产量
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杧果老龄郁闭低产园改造前后树冠、光照和产量对比 被引量:1
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作者 林凤昌 梁荫泉 +5 位作者 罗慧 罗俊奇 李秋萍 李界秋 方中斌 黄丞珏 《中国南方果树》 北大核心 2025年第2期108-113,共6页
为探寻广西杧果老龄郁闭低产园简单易行、见效快、效果好的改造方法,在南宁市该类杧果园实施重构树冠骨架结构和树冠控高控宽的改造技术,测定比较改造前及改造后不同年份株高、冠径、株行距、叶幕层厚度、树冠光照强度、产量、商品果率... 为探寻广西杧果老龄郁闭低产园简单易行、见效快、效果好的改造方法,在南宁市该类杧果园实施重构树冠骨架结构和树冠控高控宽的改造技术,测定比较改造前及改造后不同年份株高、冠径、株行距、叶幕层厚度、树冠光照强度、产量、商品果率及优果率。结果表明,株高由改造前的4.98 m下降至2.74 m,下降45.0%;行向和株向冠径由改造前的7.03 m和5.96 m分别减缩至5.54 m和4.56 m,并使行间和株间由改造前分别相互交叉1.03 m和0.96 m转变为行间和株间分别产生0.46 m和0.44 m的空隔;枝条数量由改造前的569.7条减少至279.0条,减少53.2%;叶幕层厚度由改造前的2.96 m缩减至1.57 m,减少47.0%;树冠上、中、下层光照强度分别提高1.9%、36.5%、145.1%,树冠中下层光照强度改善明显。改造后第1年产量1009.7 kg/667 m^(2);改造后2~5年平均产量1547.3 kg/667 m^(2),优质果率74.8%,商品果率95.3%。说明该改造方法达到降树高、缩树形、减重叠、透光照和丰产稳产目的,见效快,效果好,配套关键技术适宜,是杧果老龄郁闭低产园改造确实可行方法。 展开更多
关键词 杧果 老龄郁闭低产园 改造 树冠 光照 产量
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花期低温胁迫下烯效唑对红小豆抗寒生理及产量的调控作用
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作者 梁晓艳 项洪涛 +3 位作者 齐德强 李琬 赵世宏 杜吉到 《黑龙江八一农垦大学学报》 2025年第4期1-7,共7页
为探究花期低温胁迫及喷施烯效唑(S3307)对红小豆生理特性和产量的影响,以龙小豆和天津红为试验材料,在盆栽条件下,于初花期预喷S3307并连续5d低温(均温15℃)处理,测定叶片抗氧化酶活性、渗透调节物质含量和产量。结果表明:随低温胁迫... 为探究花期低温胁迫及喷施烯效唑(S3307)对红小豆生理特性和产量的影响,以龙小豆和天津红为试验材料,在盆栽条件下,于初花期预喷S3307并连续5d低温(均温15℃)处理,测定叶片抗氧化酶活性、渗透调节物质含量和产量。结果表明:随低温胁迫时间延长,红小豆叶片活性氧积累和膜脂过氧化加剧;喷施S3307能够显著缓解低温胁迫下红小豆叶片的氧化损伤,提高抗氧化酶活性,同时增加可溶性糖和脯氨酸含量;此外,S3307处理使低温胁迫导致的产量损失降低5.05%~66.48%。综上,S3307在低温胁迫下对小豆的生理特性和产量具有积极调控作用。 展开更多
关键词 红小豆 低温胁迫 S3307 抗寒生理 产量
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不同耐低磷水稻品种的内源激素水平差异及其与产量和磷利用率的关系 被引量:1
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作者 徐月梅 彭诗燕 +3 位作者 孙志伟 王志琴 朱宽宇 杨建昌 《中国水稻科学》 北大核心 2025年第2期231-244,共14页
【目的】探明不同耐低磷水稻品种内源激素水平的差异及其与产量和磷吸收利用的关系。【方法】以2个强耐低磷品种(耐低磷指数>0.9)和2个弱耐低磷水稻品种(耐低磷指数<0.5)为材料,采用水培种植,设置低磷(磷浓度为标准营养液中磷浓度... 【目的】探明不同耐低磷水稻品种内源激素水平的差异及其与产量和磷吸收利用的关系。【方法】以2个强耐低磷品种(耐低磷指数>0.9)和2个弱耐低磷水稻品种(耐低磷指数<0.5)为材料,采用水培种植,设置低磷(磷浓度为标准营养液中磷浓度的1/20,0.401 mg/L)和正常磷(8.02 mg/L)两个处理。【结果】与正常磷相比,低磷显著降低了两类品种的产量和磷的吸收量,但提高了磷素干物质生产效率和磷产谷利用率。在低磷处理下,与弱耐低磷品种相比,强耐低磷品种具有较高的产量、磷吸收量、磷利用效率、根干质量、地上部干质量和根系氧化力,根和叶中具有较高的生长素、玉米素及其核苷、脱落酸、茉莉酸类(茉莉酸和茉莉酸甲酯)、油菜素甾醇(24-表油菜素内酯和28-高油菜素内酯)含量,根中具有较高的独脚金内酯含量。这些激素水平与产量、磷吸收利用率、根干质量、地上部干质量和根系氧化力呈显著或极显著正相关;而根和叶中乙烯释放速率和1-氨基环丙烷-1-羧酸含量表现为强耐低磷品种显著低于弱耐低磷品种,并与产量和磷利用率显著或极显著负相关。随机森林分析表明,在各类激素中茉莉酸类和油菜素甾醇对产量和磷利用率的贡献最大。【结论】在低磷胁迫下,强耐低磷品种内源激素之间的平衡,特别是较高的茉莉酸类和油菜素甾醇含量,有利于优化根系形态,维持较高的根系活性,促进磷的吸收和利用,获得较高产量。 展开更多
关键词 水稻 耐低磷 产量 磷吸收利用 内源激素
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直接淬火对590 MPa含铜HSLA钢组织演变及力学性能的影响 被引量:1
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作者 王惟一 潘应君 +2 位作者 周乃鹏 柴锋 罗小兵 《金属热处理》 北大核心 2025年第3期118-124,共7页
对比离线淬火(Q)工艺,研究了直接淬火(DQ)工艺对590 MPa含铜HSLA钢组织演变及力学性能的影响。对经两种工艺处理后的试样,借助光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)分析其微观组织,通过拉伸试验、冲击... 对比离线淬火(Q)工艺,研究了直接淬火(DQ)工艺对590 MPa含铜HSLA钢组织演变及力学性能的影响。对经两种工艺处理后的试样,借助光学显微镜(OM)、扫描电镜(SEM)、电子背散射衍射(EBSD)和透射电镜(TEM)分析其微观组织,通过拉伸试验、冲击试验测试了其抗拉强度、屈服强度和低温韧性。结果表明,DQ工艺保留了控制轧制获得的大位错密度和细小晶粒,DQ试验钢的显微组织呈现压扁拉长的状态,Q试验钢的显微组织则为等轴晶粒,DQ试验钢的有效晶粒尺寸较Q试验钢更小,但强度和低温韧性差别不大。后续回火过程中产生了富Cu相和碳化物的析出,利用位错、细晶、沉淀等增强作用提高材料的屈服强度,并利用细晶强化弥补了位错密度增加、压扁状组织等因素造成的韧性下降。经直接淬火+680℃回火后试验钢综合性能最佳,其屈服强度较离线淬火+680℃回火(QT680)试验钢提高159 MPa,达到805 MPa,-84℃冲击吸收能量达到了248 J。 展开更多
关键词 含铜HSLA钢 直接淬火 屈服强度 低温韧性
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水稻对弱光胁迫的响应及适应机制研究进展 被引量:5
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作者 张银 张运波 《中国生态农业学报(中英文)》 北大核心 2025年第1期40-55,共16页
水稻是我国最重要的粮食作物之一,光照对其产量和品质形成具有重要影响。随着全球气候恶化,阴雨寡照天气频发,随之带来的弱光胁迫已成为影响水稻高产稳产、优质生产的重要限制因素。水稻安全稳定、可持续生产对保障我国粮食安全、满足... 水稻是我国最重要的粮食作物之一,光照对其产量和品质形成具有重要影响。随着全球气候恶化,阴雨寡照天气频发,随之带来的弱光胁迫已成为影响水稻高产稳产、优质生产的重要限制因素。水稻安全稳定、可持续生产对保障我国粮食安全、满足人们对粮食的需求具有重要意义。因此,本文对近些年的研究成果进行总结,综述了弱光胁迫对水稻根茎叶和花器官的形态特征、光合特性、花粉受精、同化物转运和淀粉合成酶的生理特征,氮代谢、激素调节、光受体调节、抗氧化系统和渗透调节的生化特征,以及对产量和品质的影响,重点关注水稻对弱光胁迫的分子响应机制;并展望未来水稻耐荫性研究的方向和热点,指出未来要更加深入研究水稻在遗传水平上对弱光胁迫的适应机制以及相关耐荫基因的挖掘。本研究旨在全面了解水稻耐荫分子响应机制,为选育耐荫品种提供新的思路和策略。 展开更多
关键词 水稻 弱光胁迫 产量和品质 形态特征 生理生化特征 耐荫基因
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高强低屈强比建筑用钢的热变形行为与动态再结晶模型
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作者 潘丽芳 陈勇 +3 位作者 王欢欢 张涛 张红旭 刘光明 《材料热处理学报》 北大核心 2025年第8期209-216,236,共9页
基于自主研发的高强度低屈强比建筑用钢,采用Gleeble-3800热模拟试验机在不同变形温度(770~1050℃)和应变速率(1~20 s^(-1))条件下对其进行热压缩试验,并对其真应力-真应变曲线进行分析,基于不同变形条件下的真应力-真应变曲线特征建立... 基于自主研发的高强度低屈强比建筑用钢,采用Gleeble-3800热模拟试验机在不同变形温度(770~1050℃)和应变速率(1~20 s^(-1))条件下对其进行热压缩试验,并对其真应力-真应变曲线进行分析,基于不同变形条件下的真应力-真应变曲线特征建立其动态再结晶模型。结果表明:试验钢对变形温度和应变速率具有敏感性,随着变形温度的升高或应变速率的降低,流变应力呈下降趋势;试验钢在高温热变形过程中发生了典型的动态再结晶行为,且更高的变形温度和较慢的应变速率有利于动态再结晶的发生。 展开更多
关键词 建筑用钢 低屈强比 热变形行为 动态再结晶
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