检索结果-南通市图书馆

在线全文

学校读者我要写书评

暂无评论

层冰作用下直立圆柱结构冰载荷研究

船舶力学 2024年第2期28卷 169-178页

作者：余朝歌田于逵刚旭皓孔帅季少鹏王迎晖中国船舶科学研究中心江苏无锡214082

层冰是冰区海工结构作业时遭遇的主要冰况之一,直立结构是海工结构的常见构型,因此,开展层冰作用下直立结构冰载荷研究对海工结构抗冰强化设计和安全评估具有重要意义。本文首先对层冰与直立结构作用过程进行概括分析。然后开展直立圆... 详细信息

层冰是冰区海工结构作业时遭遇的主要冰况之一,直立结构是海工结构的常见构型,因此,开展层冰作用下直立结构冰载荷研究对海工结构抗冰强化设计和安全评估具有重要意义。本文首先对层冰与直立结构作用过程进行概括分析。然后开展直立圆柱结构冰载荷的机理性试验,研究层冰的失效行为以及结构冰载荷的特征。最后基于黏聚单元模型和海冰软化本构开发层冰与结构作用模拟的数值仿真模型,对层冰的裂纹扩展和破碎过程进行模拟,同时利用试验数据对数值仿真模型的正确性进行验证。本研究工作可为结构冰载荷的数值和试验研究奠定重要基础,为冰区海工结构的设计建造提供技术参考。

关键词：层冰直立结构冰载荷模型试验黏聚单元模型

在线全文

学校读者我要写书评

暂无评论

金融促进我国体育产业的发展现状及路径分析

兰州文理学院学报（自然科学版） 2024年第5期38卷 100-104页

作者：杨纪旺邵继萍兰州理工大学体育教学部甘肃兰州730050 兰州财经大学体育教学部甘肃兰州730020

我国体育产业要实现提质增效,需要金融的有力促进.目前金融体系在体育产业中的功能尚未充分发挥.文章从金融促进体育产业投融资规模和具体手段入手,分析了我国金融促进体育产业发展现状以及面临的困境:体育产业立法不完善,为体育企业投... 详细信息

我国体育产业要实现提质增效,需要金融的有力促进.目前金融体系在体育产业中的功能尚未充分发挥.文章从金融促进体育产业投融资规模和具体手段入手,分析了我国金融促进体育产业发展现状以及面临的困境:体育产业立法不完善,为体育企业投融资提供服务的金融中介机构少,体育+金融人才匮乏.针对这些问题和困境提出了发展路径.

关键词：金融体育产业体育+金融

工作场所空气中2,3-丁二酮测定的衍生化-高效液相色谱法

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

中华劳动卫生职业病杂志 2024年第2期42卷 129-132页

作者：叶海朋傅红邵吉单晓月张玲张磊杭州市职业病防治院卫生检测科杭州310014

目的建立磷酸溶液采集、衍生化-高效液相色谱法测定工作场所空气中2,3-丁二酮(简称丁二酮)。方法于2022年10月,用多孔玻板吸收管盛装0.01%的磷酸溶液10 ml,以0.2 L/min流量采集工作场所空气中丁二酮,吸收液经2,4-二硝基苯肼衍生化75 min... 详细信息

目的建立磷酸溶液采集、衍生化-高效液相色谱法测定工作场所空气中2,3-丁二酮(简称丁二酮)。方法于2022年10月,用多孔玻板吸收管盛装0.01%的磷酸溶液10 ml,以0.2 L/min流量采集工作场所空气中丁二酮,吸收液经2,4-二硝基苯肼衍生化75 min,SB-C18色谱柱(250 mm×4.6 mm,5 μm)分离,在30 ℃柱温下,用乙腈-水(V∶V,1∶1)混合液作流动相,以1.0 ml/min的流速洗脱,紫外检测器(λ=365 nm)检测,保留时间定性,外标法定量。结果本方法中丁二酮的磷酸溶液吸收样在4 ℃下可保存7 d,在0.05~6.00 μg/ml范围内线性关系良好,线性回归方程为y=89.610x+0.133,r=0.999 9,采样效率为98.33%~100.00%,方法的检出限为0.005 μg/ml,最低检出浓度为0.016 mg/m3(以V0=3.0 L计),方法回收率为95.96%~102.44%,批内精密度为4.36%~7.78%,批间精密度为4.96%~6.06%。结论本方法简单实用,准确度好,灵敏度高,可防止丁二酮损失降解,可用于工作场所空气中丁二酮的检测。

关键词：工作场所空气 2,3-丁二酮衍生化高效液相色谱法

Nonlinear Internal Damping of Wave Equations with Variable Coefficients

在线全文

学校读者我要写书评

暂无评论

Acta Mathematica Sinica,English Series 2004年第6期20卷 1057-1072页

作者： shao ji FENG De Xing FENG Academy of Mathematics and Systems Science Chinese Academy of SciencesBeijing 100080P.R.China Institute of Systems Science Academy of Mathematics and Systems ScienceChinese Academy of Sciences

For wave equations with variable coefficients on regions which are not necessarily smooth, we study the energy decay rate when a nonlinear damping is applied on a suitable subrigion.

关键词： Wave equations Energy decay rate Nonlinear internal damping Riemannian manifold

Melilite-derived mineral inclusions in chromite from the Gaositai complex: Implications for an extensional tectonic setting in Early Permian at the north North China Craton

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2016年第3期59卷 583-589页

作者： shao ji An TIAN Wei WEI Chun jing ZHU Wen Ping Key Laboratory of Orogenic Belts and Crustal Evolution Ministry of Education School of Earth and Space Sciences Peking University

The Early Permian mafic-ultramafic concentrically zoned Gaositai intrusion at Chengde, on the northern margin of the North China Craton(NCC), is a cumulative complex emplaced along a giant fracture that penetrates deeply into the continental lithosphere. Melt inclusions are present in chromite crystals from the inner dunite and chromitite zones of the Gaositai complex. The melt inclusions have experienced post-trap crystallization and resulted in multiple mineral phases, including melilite, garnet, phlogopite, magnesite and apatite, which can indicate the liquidus minerals of the primitive magma. The characteristics of the melilite+melanite+clinopyxene assemblage indicate that the primary parental magma was highly undersaturated and derived from an alkali-rich mantle source. The crystallization of phlogopite, magnesite and apatite suggests a primary magma rich in K, H_2O and CO_2. When compared with experimental data, the primary magma of the Gaositai intrusion is concordant with a kamafugite magma originating from partial melting of enriched mantle with H_2O and CO_2 at pressures greater than 2.7 GPa. This magmatic process would have been related to extensional thinning of the continental lithosphere. The Gaositai primary magmas have high Nb/La ratios, which are similar to those of ocean island basalts, but different from arc-related magmas. This suggests that the northern margin of the NCC was not an active continental margin of the Paleo-Asian Ocean subduction zone during the Early Permian: an extensional tectonic setting during the emplacement of the Gaositai intrusion is more likely.

关键词： Melt Inclusion Melilite Primary melt Extension Continental lithosphere North China Craton

Transport of cadmium from soil to grain in cereal crops: A review

在线全文

学校读者我要写书评

暂无评论

Pedosphere 2021年第1期31卷 3-10页

作者： jian Feng MA Ren Fang SHEN ji Feng shao Institute o f Plant Science and Resources Okayama UniversityChuo 2-20-1Kurashiki 710-0046Japan State Key Laboratory of Soil and Sustainable Agriculture Institute of Soil ScienceChinese Academy of SciencesNanjing 210008China State Key Laboratory of Subtropical Silviculture Zhejiang A&F UniversityLin'An 311300China

Due to rapid urbanization and industrialization, many soils for crop production are contaminated by cadmium(Cd), a heavy metal highly toxic to many organisms. Cereal crops such as rice, wheat, maize, and barley are the primary dietary source of Cd for humans, and reducing Cd transfer from soil to their grains is therefore an important issue for food safety. During the last decade, great progress has been made in elucidating the molecular mechanisms of Cd transport, particularly in rice. Inter-and intraspecific variations in Cd accumulation have been observed in cereal crops. Transporters for Cd have been identified in rice and other cereal crops using genotypic differences in Cd accumulation and mutant approaches. These transporters belong to different transporter families and are involved in the uptake, vacuolar sequestration, root-to-shoot translocation, and distribution of Cd. Attempts have been made to reduce Cd accumulation in grains by manipulating these transporters through overexpression or knockout of the transporter genes, as well as through marker-assisted selection breeding based on genotypic differences in Cd accumulation in the grains. In this review, we describe recent progress on molecular mechanisms of Cd accumulation in cereal crops and compare different molecular strategies for minimizing Cd accumulation in grains.

关键词： barley gene knockout gene overexpression genotypic difference maize rice transporter wheat

A novel absorptive thin film for laser welding in optoelectronic device capsulation

在线全文

学校读者我要写书评

暂无评论

光学精密工程 2005年第4期13卷 492-499页

作者： jiANG shao-ji jiN Tao LI Wei-duo WANG He-zhou State Key Laboratory of Optoelectronic Materials and Technologies Sun Yat-Sen University Guangzhou 510275 China

A kind of absorptive thin film was designed and used in laser welding of SiO2, Si and LiNbO3. This absorptive thin film of three-layer metal-dielectric-metal structure is designed for further reducing the high reflectance of the Nd:YAG laser beam on the surface of the tin layer that is utilized as solder between the transparent parent materials. The actual absorption of laser energy in experiment exceeds 99%. This combination of absorber and solder transformed the laser energy into heat efficiently and decreased the minimum necessary incident laser power transmitting through the transparent parent materials. As a result, the damage of the parent materials, which is suffered from laser transmission, was avoided; On the other hand, mechanical stability of the welded materials had been improved. Experiment had been made to show the difference between welding with and without the absorptive thin film.

关键词：光电子装置封装工艺薄膜激光仪器激光技术

Relationship between Mesozoic Magmatism and Subduction in the Da Hinggan-Yanshan Area

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2001年第1期75卷 1-8页

作者： shao ji'an LIU Futian CHEN Hui HAN Qingjun Peking University Beijing 100871 Institute of Geology and Geophysics Chinese Academy of SciencesBeijing 100101

High-resolution tomographic images of the belt crossing the Japan Trench-Changbai Mountains-Dong Ujimqin Qi are represented in this paper, revealing the shape of a subducted slab in the western Pacific region and characteristics of the lithospheric structures under the Changbai Mountains and the Da Hinggan Mountains. Studies of the spatial distribution, subduction time and the time-lag between the subduction and magmatism, combined with petrology and isotope geochemistry of the Late Mesozoic volcano-plutonic rocks from the Da Hinggan Mountains-Yanshan Mountains have further proved the independence of magmatic activities from the subduction of the Pacific plate. The Mesozoic tectono-thermal evolutionary history and structural characteristics of the lithosphere in the Da Hinggan Mountains and North China suggest that the formation and evolution of magma have probably a close relationship with the delamination and thinning of the continental lithosphere and the underplating resulting from the consequent upwelling of the asthenosphere. On the other hand, the large-scale strike-slip fault system, resulting from sinistral shearing of the Pacific plate relative to the Asian continent in the Mesozoic, is responsible for the formation and emplacement of magma on the continental margin. It was the intense crust-mantle interaction, together with structural deformation at the shallower levels that led to the large tectono-magmatic belt in the East Asian continental margin.

关键词： Da Hinggan-Yanshan Mountains volcanic-plutonic rock subduction tomographic image

Cumulate complex xenoliths in the Early Mesozoic in eastern Inner Mongolia

在线全文

学校读者我要写书评

暂无评论

Chinese Science Bulletin 1999年第14期44卷 1272-1279页

作者： ji’an shao Qingjun Han Luqiao Zhang Baolei Mu Peking Univ Beijing 100871 Peoples R China Acad Sinica Inst Geol Beijing 100029 Peoples R China Geol Inst Inner Mongolia Hohhot 010020 Peoples R China

Mafic xenoliths occur in Mesozoic diorites from nine localities in eastern Inner Mongolia from the Da Hinggan Mrs. to Huabei craton. Their petrologic and geochemical features suggest that they are an intact suite of cumulate complex whose mineral assemblages contain typical patent mantle metasomatism minerals such as pargosite, phlogopite and apatite. Their REEs and trace element characteristics suggest a comagmatic relationship in these cumulates with different compositions. Isotopic dating of the xenoliths indicates that they are products of the mantle magmatic underplating in the Early Mesozoic (237—224 Ma), and they may provide direct evidence for the crust-mantle interaction and vertical accretion of continental crust under a background of the mantle upwelling in the Early Mesozoic in Huabei region.

关键词： cumulate underplating. crust-mantle interaction Early Mesozoic. eastern Inner Mongolia.