检索结果-南通市图书馆

A molecular simulation study of Cs-Cl and Cs-F ion pairs in hydrothermal fluids

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2022年第3期41卷 325-334页

作者： Xi Zhang xiandong liu Tianhua Wang Xiancai Lu Rucheng Wang State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing UniversityNanjing 210023JiangsuChina

Magmatic-hydrothermal processes play an important role in the transport, enrichment, and mineralization of cesium. In this study, classical molecular dynamics simulations were performed to investigate the properties of Cs-Cl and Cs-F ion pairs in hydrothermal fluids. The association constants(log_(10)K_(A)(m)) under a wide range of temperature(i.e. 298–1273 K) and fluid density(i.e. 0.1–1.0 g/cm^(3)) were derived from the potential of mean force(PMF) curves. The results indicate that CsCl and Cs-F ion pairs have similar stabilities. This is different from other alkali metal cations(e.g., Li^(+), Na^(+), and K^(+)), which prefer binding with F over Cl. The stabilities of Cs-Cl and Cs-F ion pairs increase with increasing temperature(except for the fluid density ≤ 0.1 g/cm^(3)) or decreasing fluid density, which is similar to other alkali halide ion pairs. Comparisons among the stabilities of CsCl/F and other alkali halide ion pairs indicate that the Li–F ion pair has the highest stability in hydrothermal fluids.

关键词： Cesium Hydrothermal fluids Association constant Hydration structure Molecular dynamics

A molecular dynamics study of uranyl-carbonate complexes adsorbed on basal surfaces of clay minerals

在线全文

学校读者我要写书评

暂无评论

Chinese Journal Of Geochemistry 2015年第2期34卷 143-155页

作者： Lei Li xiandong liu Xiancai Lu State Key Laboratory for Mineral Deposits Research School of Earth Sciences and EngineeringNanjing University

We use molecular dynamics simulation to study the mechanisms involved in the adsorption of aqueous uranyl species(UO_2^(2+)) to the basal surfaces of clay minerals,including kaolinite,pyrophyllite and *** ion can form various complexes with carbonates,namely,[UO_2(H_2O)_5]^(2+),[UO_2(H_2O)3(CO_3)],[UO_2(H_2O)2(CO_3)_2]^(2-),[UO_2(CO_3)_3]^(4-).The simulations show that at aqueous clay interfaces,both uranyl species and surface type control the adsorption *** noncarbonato and monocarbonato uranyl species can form outer-sphere complexes on siloxane surfaces through electrostatic interaction,but the dicarbonato and tricarbonato uranyl complexes rarely adsorb on the siloxane *** outer-sphere adsorptions of the uranylcarbonate complexes on gibbsite surfaces are observed,which are fixed by hydrogen bonds between the ligands(carbonate and/or H_2O) and surface *** sorption behaviors derived in this study provide new insights into understanding the migration and enrichment of uranium and other radionuclides.

关键词：分子动力学模拟表面羟基吸附机制双氧铀碳酸酯黏土矿物铀酰络合物基底

Molecular simulation study on K^＋-Cl^- ion pair in geological fluids

在线全文

学校读者我要写书评

暂无评论

Acta Geochimica 2017年第1期36卷 1-8页

作者： Mengjia He xiandong liu Xiancai Lu Rucheng Wang State Key Laboratory for Mineral Deposits Research School of Earth Sciences and Engineering Nanjing UniversityNanjing 210046 People's Republic of China

This paper reports a classical molecular dynamics study of the potential of mean forces(PMFs),association constants,microstructures K^+-Cl^- ion pair in supercritical *** constrained MD method is used to derive the PMFs of K^+-Cl^- ion pair from 673 to 1273 K in low-density water(0.10-0.60 g/cm).The PMF results show that the contact ion-pair(CIP) state is the one most energetically favored for a K^+-Cl^- ion *** association constants of the K^+-Cl^- ion pair are calculated from the PMFs,indicating that the K^+-Cl^- ion pair is thermodynamically *** gets more stable as T increases or water density *** microstructures of the K^+-Cl^- ion pair in the CIP and solvent-shared ion-pair states are characterized in ***,we explore the structures and stabilities of the KCl-Au(I)/Cu(I) complexes by using quantum mechanical *** results reveal that these complexes can remain stable for T up to1273 K,which indicates that KCl may act as a ligand complexing ore-forming metals in hydrothermal fluids.

关键词： Molecular dynamics KCl Potential of mean force Association constant Geometry optimization

Material Properties of Marine Hydrogenous Ferromanganese Crust and Its Performance in Desulfurization

在线全文

学校读者我要写书评

暂无评论

Acta Geologica Sinica(English Edition) 2006年第3期80卷 441-450页

作者： LU Xiancai HOU Qingfeng liu xiandong YANG Kan WANG Rucheng LING Hongfei XU Shijin State Key Laboratory for Mineral Deposits Research Department of Earth Sciences Nanjing University Nanjing Jiangsu 210093

Marine hydrogenous ferromanganese crust, an important metal resource in the future, has significant potential in various applications as a type of natural nano-structured material. By employing scanning electronic microscopy, nitrogen adsorption-desorption isotherm measurement, Xray fluorescence spectrometer and X-ray diffraction methods, the micro-structure, surface properties and chemical composition of several plate-like ferromanganese crusts sampled from the northwestern Pacific were investigated comprehensively. Although obvious differences were observed from different layers, the crust is a typical porous material with high specific surface area, unique pore structure and abundant transition elements. Furthermore, the performance of natural crust in desulfurization process was preliminarily tested in laboratory experiments. The suffur capacities of the crust are 13.1% and 18.1% at room temperature and 350 ℃, respectively. The crust can be used not only as a metal resource, but also as an environmental material.

关键词： ferromanganese crust pore structure surface property desulfurization

在线全文

学校读者我要写书评

暂无评论

爆裂轮胎精确建模及其动态特性仿真方法研究

汽车工程 2023年第5期45卷 854-864,872页

作者：贾雪峰冯启章刘献栋单颖春北京航空航天大学交通科学与工程学院北京100191

汽车行驶中轮胎突然爆裂是极其危险的行驶工况,但轮胎爆裂过程的准确测试分析难度很大,而其现有仿真方法因需大幅简化使得难以描述轮胎爆裂过程的瞬态特性。针对此问题,本文中提出分别模拟胎内、外空气,且考虑轮胎各种材料失效特性、胎... 详细信息

汽车行驶中轮胎突然爆裂是极其危险的行驶工况,但轮胎爆裂过程的准确测试分析难度很大,而其现有仿真方法因需大幅简化使得难以描述轮胎爆裂过程的瞬态特性。针对此问题,本文中提出分别模拟胎内、外空气,且考虑轮胎各种材料失效特性、胎内空气与轮胎车轮总成流-固耦合的汽车轮胎爆裂过程仿真分析方法,实现轮胎滚动中爆胎过程的瞬态动力学特性仿真;并通过对比仿真和理论计算结果,验证仿真模型的正确性;同时,通过计算还获得爆裂轮胎内部空气泄漏规律和路面对轮胎径向力的变化特性,以及轮胎速度、胎压与裂口尺寸对爆胎过程持续时间和轮胎力学特性的影响机理。本文工作聚焦于仿真方法研究,对掌握爆裂轮胎瞬态特性、研究爆胎后整车动力学控制策略具有意义。

关键词：轮胎爆裂材料失效流-固耦合结构化任意拉格朗日-欧拉算法

Development history and technological progress of non-oriented electrical steel sheets at Baosteel

在线全文

学校读者我要写书评

暂无评论

Baosteel Technical Research 2013年第4期7卷 48-55页

作者： liu xiandong CHEN Mao WANG Bo WANG Feng Silicon Steel Department Baoshan Iron & Steel Co.Ltd.

This paper briefly summarized the development history, product catalogue and magnetic properties of non- oriented electrical steel sheets at Baosteel, as well as the development and application of high-value-added steel grades. Recent advances in manufacturing electrical steel sheets were also introduced, including technologies for controlling inclusion,for producing high-grade steel strips by a tandem rolling mill and for controlling the transverse thickness difference of steel sheets, and the development of environmentally friendly coatings.

关键词： non-oriented electrical steel magnetic property inclusion transverse thickness difference environmentallyfriendly coating steel grade development

Development of top high-grade non-grain-oriented silicon steels at Baosteel

在线全文

学校读者我要写书评

暂无评论

Baosteel Technical Research 2013年第1期7卷 3-8页

作者： XIE Shishu CHEN Xiao ZHANG Pijun liu xiandong Silicon Steel Department Baoshan Iron & Steel Co.Ltd. Research Institute Baoshan Iron & Steel Co.Ltd.

The development, production and application of top high-grade non-grain-oriented （NGO） silicon steels at Baosteel were introduced in this paper. Top high grades refer to the highest grades in the intemational silicon steel product standard and above. B35A230 and B50A250 were developed at Baosteel in 2009 and have been used in inverter compressors for air-conditioners, small transformers and big hydropower generators in the Three Gorges project. Small- batch production of B35A210 and B50A230, which exceed the highest grades listed in the intemational silicon steel product standard,began in 2010. That was a breakthrough in the silicon steel making history in China. Presently,Baosteel＇ s high- grade NGO products have passed the strict qualifications of the three major electric power equipment manufacturers in China and the leading international power equipment suppliers like ALSTOM, GE, SIEMENS, VESTAS, etc. These products are characterized by low iron loss, low anisotropy, good punchability and a high lamination factor. They have been used in the 770 MW hydropower generator at Xiluodu Power Station in the three gorges area, 1 000 MW thermal power generators and 2.5 MW wind power generators.

关键词： high-grade non-grain-oriented silicon steel iron loss anisotropy

内嵌异质声学黑洞阵列板结构的阻尼演化机制研究

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2023年第3期39卷 153-167页

作者：鲍岳刘献栋姚政成张悦单颖春何田 School of Transportation Science and Engineering Beihang UniversityBeijing100191China

声学黑洞是一种有效的被动减振结构.这种结构的特点在于可以俘获结构中的弯曲波形成高能量密度区域,从而通过附加阻尼材料来实现高效率的振动能量耗散.基于这种声学黑洞效应,本文通过有限元仿真与实验探究了单个声学黑洞与声学黑洞阵列... 详细信息

声学黑洞是一种有效的被动减振结构.这种结构的特点在于可以俘获结构中的弯曲波形成高能量密度区域,从而通过附加阻尼材料来实现高效率的振动能量耗散.基于这种声学黑洞效应,本文通过有限元仿真与实验探究了单个声学黑洞与声学黑洞阵列的动力学性能.研究发现,声学黑洞阵列可以有效地提高整体板结构的模态密度和模态损耗因子,从而在较宽的频率范围下实现更好的减振性能.为了进一步揭示声学黑洞结构的阻尼损耗机理,建立了声学黑洞与阻尼材料的耦合模型并进行了参数化讨论.结果表明,系统的模态损耗因子不仅与阻尼材料的性能有关,而且还取决于阻尼材料所覆盖的结构模态动能的大小.同时,模态密度则由结构的几何尺寸决定.此外,本文对声学黑洞阵列中不同单元的作用也进行了探讨,并分析了不同类型声学黑洞阵列结构的动力学性能.结果表明,异质声学黑洞阵列比传统的均匀阵列在宽频范围内具有更稳定的动力学性能.这些研究有利于声学黑洞阵列在减振降噪方面的实际工程应用.

关键词： Acoustic black hole Modal analysis ABH array Damping Vibration reduction

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

并串联复合机器人的鲁棒控制

机械工程学报 2006年第9期42卷 229-232页

作者：周兵许艳湖南大学机械与汽车工程学院长沙410082

针对并联机构具有较高的刚度和精度,但工作空间小的特点,提出一种由3自由度平动并联机构和放大机构相结合的机构,从而组成新型并串联复合机器人。根据拉格朗日方法,建立并串联复合机器人的动力学方程, 并讨论动力学方程的性质。研究并... 详细信息

针对并联机构具有较高的刚度和精度,但工作空间小的特点,提出一种由3自由度平动并联机构和放大机构相结合的机构,从而组成新型并串联复合机器人。根据拉格朗日方法,建立并串联复合机器人的动力学方程, 并讨论动力学方程的性质。研究并串联复合机器人的鲁棒控制问题,根据动力学的性质在笛卡儿坐标系中设计一种鲁棒控制策略。控制器由两部分组成:一部分为基于标称模型设计的计算力矩控制器,其作用是镇定标称的机器人系统;另一部分为一种基于Lyapunov方法设计的鲁棒控制器,其作用是消除不确定性对跟踪性能的影响。理论分析与仿真结果表明,该控制器对改善并串联复合机器人的轨迹跟踪精度十分有效。

关键词：并串联复合机器人鲁棒控制 Lyapunov方法

同方期刊数据库