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Fast filtering algorithm based on vibration systems and neural information exchange and its application to micro motion robot 被引量:4
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作者 高娃 查富生 +1 位作者 宋宝玉 李满天 《Chinese Physics B》 SCIE EI CAS CSCD 2014年第1期159-169,共11页
This paper develops a fast filtering algorithm based on vibration systems theory and neural information exchange approach. The characters, including the derivation process and parameter analysis, are discussed and the... This paper develops a fast filtering algorithm based on vibration systems theory and neural information exchange approach. The characters, including the derivation process and parameter analysis, are discussed and the feasibility and the effectiveness are testified by the filtering performance compared with various filtering methods, such as the fast wavelet transform algorithm, the particle filtering method and our previously developed single degree of freedom vibration system filtering algorithm, according to simulation and practical approaches. Meanwhile, the comparisons indicate that a significant advantage of the proposed fast filtering algorithm is its extremely fast filtering speed with good filtering perfi^rmance. Further, the developed fast filtering algorithm is applied to the navigation and positioning system of the micro motion robot, which is a high real-time requirement for the signals preprocessing. Then, the preprocessing data is used to estimate the heading angle error and the attitude angle error of the micro motion robot. The estimation experiments illustrate the high practicality of the proposed fast filtering algorithm. 展开更多
关键词 fast filtering vibration system neural information exchange micro motion robot
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Proton Exchange in Water/Mycelium System: Transdisciplinary Out-of-Equilibrium Thermodynamic Approach Using Potentiometric Titration
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作者 Vicente R. de Almeida Bruno Szpoganicz 《Open Journal of Physical Chemistry》 2013年第4期189-200,共12页
In this study, we used potentiometric titration to investigate the interaction of the saprophytic fungus Trametes villosa in an aqueous environment. The study of this biological complex system allowed us to observe th... In this study, we used potentiometric titration to investigate the interaction of the saprophytic fungus Trametes villosa in an aqueous environment. The study of this biological complex system allowed us to observe the evolution of out-ofequilibrium hydrogen ion potential states after systematic perturbations. The responses of the complex system to perturbations were interpreted from relations that provided qualitative response patterns for mycelium in agreement with their basic structural and organizational characteristics. We consider this to be a transdisciplinary example of the behavior of general systems with thermodynamic properties of great ecological relevance, being specifically related to the negentropic properties of heterogeneous systems. 展开更多
关键词 Transdisciplinarity FUNGI PROTON exchange Out-of-equilibrium THERMODYNAMICS pH Ecological Relations
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Using NMR-detected hydrogen-deuterium exchange to quantify protein stability in cosolutes,under crowded conditions in vitro and in cells
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作者 I-Te Chu Gary J.Pielak 《Magnetic Resonance Letters》 2023年第4期319-326,共8页
We review the use of nuclear magnetic resonance(NMR)spectroscopy to assess the exchange of amide protons for deuterons(HDX)in efforts to understand how high concentration of cosolutes,especially macromolecules,affect ... We review the use of nuclear magnetic resonance(NMR)spectroscopy to assess the exchange of amide protons for deuterons(HDX)in efforts to understand how high concentration of cosolutes,especially macromolecules,affect the equilibrium thermodynamics of protein stability.HDX NMR is the only method that can routinely provide such data at the level of individual amino acids.We begin by discussing the properties of the protein systems required to yield equilibrium thermodynamic data and then review publications using osmolytes,sugars,denaturants,synthetic polymers,proteins,cytoplasm and in cells. 展开更多
关键词 Amide proton exchange Cosolutes equilibrium thermodynamics Macromolecular CROWDING OSMOLYTES Protein stability
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低延迟低抖动的FAST解码器设计与实现
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作者 张曦煌 丁楠 +2 位作者 柴志雷 冯一飞 叶钧超 《应用科学学报》 CAS CSCD 北大核心 2023年第4期705-717,共13页
为了解决金融FAST(financial information exchange adapted for streaming)协议面临的纯软件解码延迟高,FPGA(field programmable gate array)硬件解码开发周期长、更新困难的问题,提出了基于OpenCL和HLS的硬件解码模式。通过对FAST数... 为了解决金融FAST(financial information exchange adapted for streaming)协议面临的纯软件解码延迟高,FPGA(field programmable gate array)硬件解码开发周期长、更新困难的问题,提出了基于OpenCL和HLS的硬件解码模式。通过对FAST数据解码的标记、切分、合并、解码模块进行流水优化,对切分和字段解码进行并行操作,将数据的输入输出改为流式接口减少I/O口的延时以及对切分数组进行分割映射等优化方式实现了解码过程低延迟、低抖动。实验结果表明,相比纯软件解码,本文提出的解码器处理速度提升了11倍,解码延迟缩短至1/6,抖动幅度控制在10 ns之内。相比传统HDL方式的FPGA定制硬件开发,开发效率可提升3~4倍,从而更好地满足产品更新换代的需求。 展开更多
关键词 OPENCL 低延迟低抖动 fast协议解码 高层次综合 现场可编程门阵列
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考虑负荷时空均衡和弹性响应的电动汽车快充电价定价策略 被引量:1
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作者 蔡小婷 杨健维 +2 位作者 廖凯 何正友 向悦萍 《电力自动化设备》 EI CSCD 北大核心 2024年第2期94-102,共9页
为了引导电动汽车有序充电,提出了一种考虑负荷时空均衡和弹性响应的电动汽车快充电价定价策略。引入交通流理论描述交通路网,建立电动汽车快充负荷时空分布模型;考虑配电网调度和电动汽车快充负荷的弹性需求,构建源-荷互动下的快充电... 为了引导电动汽车有序充电,提出了一种考虑负荷时空均衡和弹性响应的电动汽车快充电价定价策略。引入交通流理论描述交通路网,建立电动汽车快充负荷时空分布模型;考虑配电网调度和电动汽车快充负荷的弹性需求,构建源-荷互动下的快充电价定价架构,并基于潮流追踪法从时空双维度推导快充电价的计算方法;在此基础上,计及电动汽车负荷弹性响应特性,以提升配电网的负荷均衡性为目标,建立快充电价定价策略,并通过迭代算法求解该定价策略。算例仿真结果表明,所提定价策略能够有效引导电动汽车进行有序快充,激励电动汽车用户与配电网友好互动,提升负荷的时空分布均衡性。 展开更多
关键词 电动汽车 时空分布 快充电价 交通流 负荷均衡 弹性响应 源-荷互动 配电网
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基于PCIE的多嵌入式人工智能处理器低延迟数据交换技术
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作者 魏璇 温凯林 +3 位作者 李斌 刘淑涛 褚洁 蔡觉平 《电子科技》 2024年第5期32-37,46,共7页
针对多嵌入式人工智能(Artificial Intelligence,AI)处理器板卡之间的任务调度和数据交换冲突以及提高多板卡堆叠扩展时的可靠性和运行效率问题,文中提出了一种虫洞交换结构多嵌入式人工智能处理器高速数据交换技术和数据帧结构的解决... 针对多嵌入式人工智能(Artificial Intelligence,AI)处理器板卡之间的任务调度和数据交换冲突以及提高多板卡堆叠扩展时的可靠性和运行效率问题,文中提出了一种虫洞交换结构多嵌入式人工智能处理器高速数据交换技术和数据帧结构的解决方法。该方法基于PCIE(PCI Express)高速数据接口,将数据以数据单元的形式进行信息传递,并设计多重权重决策算法避免数据传输中的冲突,实现任务的并发多线程处理。搭建FPGA(Field Programmable Gate Array)平台进行设计和测试,结果表明PCIE的传输带宽利用效率达到了85%以上,数据交换延迟小于20μs,系统中断任务响应平均最大延迟时间为8.775μs。该技术适用于多处理器协同的高速交换电路,可扩展至混合PCIE和RapidIO交换电路结构。 展开更多
关键词 嵌入式人工智能处理器 数据交换 外围组件互连快速 PCI Express 交换开关 虫洞技术 数据仲裁 多重权重决策
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基于扩展FAST协议的金融消息压缩方法 被引量:2
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作者 徐广斌 武剑锋 +5 位作者 王泊 黄寅飞 胡汉英 刘凯 林征 白硕 《计算机工程与应用》 CSCD 2012年第1期138-141,共4页
为降低金融交换消息的大小,近年来已出现QuickFast、OpenFast等基于FAST1.1协议的金融消息压缩方法。然而现有方法不支持压缩率更高的FAST1.2协议,也无法支持面向过程的开发运行环境。提出基于扩展FAST的金融消息压缩方法FASTX,不仅可... 为降低金融交换消息的大小,近年来已出现QuickFast、OpenFast等基于FAST1.1协议的金融消息压缩方法。然而现有方法不支持压缩率更高的FAST1.2协议,也无法支持面向过程的开发运行环境。提出基于扩展FAST的金融消息压缩方法FASTX,不仅可以达到更好的编码效率和速度,还为在面向过程编程模式下实现FAST1.2提供了新的方法。实验结果表明FASTX编码效率十分高,只需约DBF1/4的大小就可表示相同的内容,与其他几种常用数据格式也进行了对比,验证了新方法的可行性和有效性。 展开更多
关键词 适流金融信息交换(fast)协议 面向过程 金融信息交换(FIX)协议
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示范快堆中间热交换器材料316H钢钠中老化行为研究
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作者 纪琤 张金权 +1 位作者 阮章顺 和雅洁 《科技资讯》 2024年第2期117-120,共4页
316H钢是中国示范快堆中间热交换器的主要材料,随着运行时间的增加,其老化效应不断累积。为探索316H钢在示范快堆中间热交换器运行工况下的老化行为,此研究分别在353℃和535℃静态钠条件下对316H钢管材和板材试样进行了1000~8000 h的相... 316H钢是中国示范快堆中间热交换器的主要材料,随着运行时间的增加,其老化效应不断累积。为探索316H钢在示范快堆中间热交换器运行工况下的老化行为,此研究分别在353℃和535℃静态钠条件下对316H钢管材和板材试样进行了1000~8000 h的相容性试验,并对试验后的样品开展微观表征、腐蚀速率测量以及力学性能测试等分析。结果显示:353℃条件下试样几乎不发生腐蚀现象,而在535℃条件下,高温加速了扩散使得材料的老化行为显著,随着试验时间的增加,材料在钠中的腐蚀转为稳态阶段。研究表明:316H钢在钠中的老化行为受到钠的温度、浸泡时间以及材料制造工艺等因素影响,在低氧低碳的低温钠环境中有较好的抗老化能力,在温度相对较高、时间较长的钠环境中存在老化迹象。 展开更多
关键词 316H钢 钠冷快堆 中间热交换器 老化 腐蚀速率
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基于扩展FAST的高速证券交易接口文件交换方法
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作者 徐广斌 武剑锋 +4 位作者 郑刚 黄寅飞 吴韶平 王泊 白硕 《小型微型计算机系统》 CSCD 北大核心 2012年第2期414-418,共5页
针对现有方法冗余度高和文件分段造成带宽浪费、延迟大的问题,提出一种基于扩展FAST的高速证券交易接口文件交换方法-FastFile.将接口文件记录映射为消息进行编码并组成段传输,使接收方即便只收到部分分段,也可解析出所含记录,同时利用... 针对现有方法冗余度高和文件分段造成带宽浪费、延迟大的问题,提出一种基于扩展FAST的高速证券交易接口文件交换方法-FastFile.将接口文件记录映射为消息进行编码并组成段传输,使接收方即便只收到部分分段,也可解析出所含记录,同时利用扩展FAST高效的编码有效降低数据冗余度.实现了扩展FAST及FastFile,实验比较了FastFile与常用接口文件格式.实验表明FastFile处理数据的粒度更小,可降低重传,数据格式比现有的接口文件格式小70%以上,验证了新方法的可行性与有效性. 展开更多
关键词 适流FIX 证券交易 数据交换
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铅-超临界二氧化碳换热器耦合流动传热特性研究
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作者 李良星 雷振欣 +3 位作者 赵浩翔 石尚 许向阳 向祖涛 《西安交通大学学报》 EI CAS CSCD 北大核心 2024年第10期212-221,共10页
为探究螺旋盘管式主换热器内的耦合流动传热机理,基于等长度分段模型,构建了以液态铅和超临界二氧化碳为工质的螺旋盘管式主换热器原型及模化比例样件的理论设计方法,并利用相似性原理完成了主换热器小比例样件设计。以主换热器小比例... 为探究螺旋盘管式主换热器内的耦合流动传热机理,基于等长度分段模型,构建了以液态铅和超临界二氧化碳为工质的螺旋盘管式主换热器原型及模化比例样件的理论设计方法,并利用相似性原理完成了主换热器小比例样件设计。以主换热器小比例样件为研究对象,通过SST k-ω湍流模型数值分析了液态铅和超临界二氧化碳在螺旋盘管换热器内的流动传热特性。计算结果表明:螺旋盘管换热器内耦合流动传热性能主要受壳侧质量流量、管侧质量流量和壳侧工质入口温度影响;管侧超临界二氧化碳质量流量对螺旋盘管换热器内耦合流动传热性能的影响最为显著,在超临界二氧化碳质量流量增加52.4%的条件下,螺旋管的平均表面换热系数增大了21.2%;在壳侧液态铅的质量流量和入口温度分别增大94.6%、20 K的情况下,螺旋管内的表面传热系数分别增大了5.5%、3.3%。该研究可为螺旋盘管式换热器的工况选择和高效设计提供理论指导。 展开更多
关键词 铅冷快堆 螺旋盘管换热器 模化比例样件 耦合流动传热
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Study on Separation of Phycoerythrin by Q-Sepharose Fast Flow 被引量:1
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作者 张彬 王翠芹 +3 位作者 高敏 张轶 顾铭 王长海 《Agricultural Science & Technology》 CAS 2012年第8期1641-1644,共4页
[Objective] This study aimed to establish an efficient process for separation of phycoerythrin by using Q Sepharose Fast Flow resin and verity its feasibility for scale-up. [Method] Elution gradient, sample volume and... [Objective] This study aimed to establish an efficient process for separation of phycoerythrin by using Q Sepharose Fast Flow resin and verity its feasibility for scale-up. [Method] Elution gradient, sample volume and flow rate were optimized to determine the optimal separation condition, under which the scale-up process was verified. [Result] The optimal condition for separation of phycoerythrin by using Q Sepharose FF resin was investigated: 30 ml of laver extract was loaded to the Q Sepharose FF column with a bed volume of 8 ml; subsequently, the column was stepwise eluted with 0-0.10-0.35-1.00 mol/L NaCI solution (pH 6.0) at a constant flow rate of 1 ml/min; the elution peak under 0.35 mol/L NaCI solution was collected, and the recovery rate and purity coefficient (A565/A280) of phycoerythrin were determined as 44.3 and 1.15, respectively. Based on the established process, 75 ml of phycoerythrin extract was loaded to the Q Sepharose FF column with a bed volume of 20 ml for separation, while no significant variation was observed in the separation result. [Conclusion] Phycoerythrin can be well separated from laver extract by using Q Sepharose FF resin and the process is feasible for scale-up. 展开更多
关键词 Ion exchange chromatography Q Sepharose fast Flow PHYCOERYTHRIN SEPARATION Scale-up
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DEAE-Sepharose Fast Flow分离纯化刺芹侧耳木质素降解酶 被引量:4
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作者 贾俊睿 陈敏 +1 位作者 梁新乐 李锋 《安徽农业科学》 CAS 北大核心 2009年第2期448-450,共3页
[目的]为Pleurotus eryngii—Co60-7木质素降解酶的分离纯化和综合利用提供试验依据。[方法]采用DEAE—Sepharose^TM Fast Flow离子交换介质,分别考察缓冲液pH值、流速和洗脱方式等对刺芹侧耳木质素降解酶分离纯化的影响,确定了最佳... [目的]为Pleurotus eryngii—Co60-7木质素降解酶的分离纯化和综合利用提供试验依据。[方法]采用DEAE—Sepharose^TM Fast Flow离子交换介质,分别考察缓冲液pH值、流速和洗脱方式等对刺芹侧耳木质素降解酶分离纯化的影响,确定了最佳分离纯化层析条件。[结果]DEAE-Sephalose^TM Fast Flow分离纯化Pleurotus eryngii-Co60-7木质素降解酶的最佳层析条件为:选择20mmol/L,pH值为5.0醋酸钠一醋酸缓冲体系,3ml/min的流速,进行分步洗脱(100、200~300和1000mmoL/L NaCl的三步洗脱),可较好地实现刺芹侧耳发酵液木质素降解酶初分,该纯化操作目标蛋白回收率达85%,纯化分离因素为2.71。[结论]该技术在分离纯化刺芹侧耳木质素降解酶上可行,具有潜在的工业应用价值。 展开更多
关键词 PLEUROTUS eryngii-Co60-7 木质素降解酶 离子交换层析 DEAE-SepharoseTM fast FLOW
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Neutronics physics analysis of a large fluoride-salt-cooled solidfuel fast reactor with Th-based fuel 被引量:1
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作者 Yu Peng Gui-Feng Zhu +2 位作者 Yang Zou Si-Jia Liu Hong-Jie Xu 《Nuclear Science and Techniques》 SCIE CAS CSCD 2017年第11期188-197,共10页
Fast reactors based on thorium fuel have enhanced inherent safety. Fluoride salt performs well as a coolant in high-temperature nuclear systems. In this paper,we present a reference core for a large fluoride-salt-cool... Fast reactors based on thorium fuel have enhanced inherent safety. Fluoride salt performs well as a coolant in high-temperature nuclear systems. In this paper,we present a reference core for a large fluoride-salt-cooled solid-fuel fast reactor(LSFR) using thorium–uranium fuel cycle. Neutronics physics of the LSFR reference core is investigated with 2D and 3D in-core fuel management strategy. The design parameters analyzed include the fuel volume fraction, power density level and continuous removal of fission products with 3D fuel shuffling that obtains better equilibrium core performance than 2D shuffling. A self-sustained core is achieved for all cases,and the core of 60% fuel volume fraction at 50 MW/m^3 power density is of the best breeding performance(average breeding ratio 1.134). The LSFR core based on thorium fuel is advantageous in its high discharge burn-up of 20–30% fissions per initial heavy metal atom, small reactivity swing over the whole lifetime(to simplify the reactivity control system), the negative reactivity temperature coefficient(intrinsically safe for all cases) and accepted cladding peak radiation damage. The LSFR reactor is a good alternative option for the deployment of a self-sustained thorium-based nuclear system. 展开更多
关键词 FLUORIDE SALTS THORIUM cycle fast reactor Core characteristics equilibrium
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Preparation of a Cation Exchanger from Cork Waste: Thermodynamic Study of the Ion Exchange Processes
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作者 M.GomezCorzo A.Maclas-Garcla 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2002年第1期57-59,共3页
An ion exchanger was prepared by sulfonation of cork-waste chars. The exchange properties of the resultant material were characterized using Na+, Ca2+ or Fe3+ aqueous solutions. The content of metal ions in the soluti... An ion exchanger was prepared by sulfonation of cork-waste chars. The exchange properties of the resultant material were characterized using Na+, Ca2+ or Fe3+ aqueous solutions. The content of metal ions in the solutions were determined by atomic absorption spectrometry. On the basis of the results obtained, the chemical equilibrium and its thermodynamic aspects related to the ion exchange process were studied. It was found that equilibrium constant K varies by the order: Na+<Ca2+<Fe3+, its value increasing with increasing temperature, and that △H°>0 and △5°>0, with -△G° following the sequence: Ca2+>Na+>Fe3+. 展开更多
关键词 CORK Cation exchanger CHAR SULFONATION equilibrium THERMODYNAMIC
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Kinetic equilibrium reconstruction for the NBI-and ICRH-heated H-mode plasma on EAST tokamak
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作者 Zhen ZHENG Nong XIANG +8 位作者 Jiale CHEN Siye DING Hongfei DU Guoqiang LI Yifeng WANG Haiqing LIU Yingying LI Bo LYU Qing ZANG 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第6期30-38,共9页
The equilibrium reconstruction is important to study the tokamak plasma physical processes.To analyze the contribution of fast ions to the equilibrium,the kinetic equilibria at two time-slices in a typical H-mode disc... The equilibrium reconstruction is important to study the tokamak plasma physical processes.To analyze the contribution of fast ions to the equilibrium,the kinetic equilibria at two time-slices in a typical H-mode discharge with different auxiliary heatings are reconstructed by using magnetic diagnostics,kinetic diagnostics and TRANSP code.It is found that the fast-ion pressure might be up to one-third of the plasma pressure and the contribution is mainly in the core plasma due to the neutral beam injection power is primarily deposited in the core region.The fast-ion current contributes mainly in the core region while contributes little to the pedestal current.A steep pressure gradient in the pedestal is observed which gives rise to a strong edge current.It is proved that the fast ion effects cannot be ignored and should be considered in the future study of EAST. 展开更多
关键词 kinetic equilibrium reconstruction NBI ICRH pressure gradient edge current fast ions
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DISCRETE TIME STOCHASTIC EQUILIBRIUM WITH INFINITE HORIZON INCOMPLETE ASSET MARKETS
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作者 Zhang ShunmingSchoolofEconomicsandManagement,TsinghuaUniv.,Beijing100084.Dept.ofEconomics,Univ.ofWesternOntario,LondonON,CanadaN6A5C2 《Applied Mathematics(A Journal of Chinese Universities)》 SCIE CSCD 2001年第2期203-218,共16页
This paper examines the existence of general equilibrium in a discrete time economy with the infinite horizon incomplete markets.There is a single good at each node in the event tree.The existence of general equilibri... This paper examines the existence of general equilibrium in a discrete time economy with the infinite horizon incomplete markets.There is a single good at each node in the event tree.The existence of general equilibrium for the infinite horizon economy is proved by taking limit of equilibria in truncated economies in which trade stops at a sequence of dates. 展开更多
关键词 General equilibrium infinite horizon incomplete asset markets infinite horizon economy truncated economy associated stochastic economy purely exchange economy.
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Effects of fast ions produced by ICRF heating on the pressure at EAST
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作者 Zhen ZHENG Nong XIANG +1 位作者 Cheng YANG Yingfeng XU 《Plasma Science and Technology》 SCIE EI CAS CSCD 2020年第2期38-46,共9页
Ion cyclotron resonance heating(ICRH),which can produce fast ions,is an important auxiliary heating method at EAST.To analyze the effect of ICRH-induced fast ions on the plasma pressure at EAST,simulations are perform... Ion cyclotron resonance heating(ICRH),which can produce fast ions,is an important auxiliary heating method at EAST.To analyze the effect of ICRH-induced fast ions on the plasma pressure at EAST,simulations are performed using TRANSP and TORIC codes.It is found that the ICRF-induced fast ion pressure cannot be negligible when the ICRF power is sufficiently high.The magnitude of the total ion pressure can be raised up to 60%of the total pressure as the input power rises above 3 MW.The pressure profile is also significantly modified when the resonant layer is changed.It is shown that by changing the wave frequency and antenna position,the total ion pressure profile can be broadened,which might provide an option for profile control at EAST. 展开更多
关键词 ICRH equilibrium fast ion pressure minority heating
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Studies of Uni-Univalent Ion Exchange Reactions Using Strongly Acidic Cation Exchange Resin Amberlite IR-120
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作者 Pravin Singare Ram Lokhande Neelima Samant 《Natural Science》 2009年第2期124-128,共5页
The selectivity behaviour of ion exchange resin Amberlite IR-120 for inorganic cations like sodium and potassium was predicted on the basis of thermodynamic data. The equilibrium constant K values calculated for uni-u... The selectivity behaviour of ion exchange resin Amberlite IR-120 for inorganic cations like sodium and potassium was predicted on the basis of thermodynamic data. The equilibrium constant K values calculated for uni-univalent ion exchange reaction systems were observed to increase with rise in temperature, indicating endothermic ion exchange reactions. From the K values calculated at different temperatures the enthalpy values were calculated. The low enthalpy and higher K values for K+ ion ex-change reaction indicates more affinity of the resin for potassium ions as compared to that for sodium ions also in the solution. The technique used in the present experimental work will be useful in understanding the selectivity behav-iour of different ion exchange resins for ions in the solution. Although the ionic selectivity data for the ion exchange resins is readily available in the literature, it is expected that the informa-tion obtained from the actual experimental trials will be more helpful. The technique used in the present experimental work when applied to dif-ferent ion exchange resins will help in there characterization. 展开更多
关键词 Ion exchange equilibrium equilibrium Constant ENTHALPY ENDOTHERMIC Reaction Amberlite IR-120
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First-principle study of Ba isotopic fractionation during ion exchange processes
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作者 Xin-Yue Ji Yan-Fang Wang +4 位作者 Le-Cai Xing Jian Liu Peng-Dong Wang Tian-Di Zhang Hao-Nan Zhao 《Acta Geochimica》 EI CAS CSCD 2022年第1期121-131,共11页
The potential utilization and development of the Ba isotope tool depend on an accurateδ^(137/134)Ba determination of the samples.During the chemical purification,whether the adsorption process on the surface of the i... The potential utilization and development of the Ba isotope tool depend on an accurateδ^(137/134)Ba determination of the samples.During the chemical purification,whether the adsorption process on the surface of the ionexchange resin could lead to the Ba isotopic fractionation and the degree of fractionation directly influence the accurateδ^(137/134)Ba determination.In the present work,first-principles calculations based on the density functional theory were used to quantify the Ba isotopic equilibrium fractionation factor between the aqueous solution and the resin in the acid leaching process.By constructing and optimizing the geometric configurations of Ba-containing species,Ba(H_(2)O)_(n)^(2+),Ba(H_(2)O)_(n)Cl_(2),Ba(H_(2)O)_(n)(NO_(3))2,and the adsorbed Ba^(2+)on the surface of the resin,extracting the harmonic vibrational frequencies,we finally at 298 K obtained the fractionations,Δ^(137/134)Ba_(soln-ads)=0.07‰,Δ^(137/134)Ba_(Ba(H_(2)O)_(n)Cl_(2)-ads)=0.05‰,andΔ^(137/134)-Ba^(Ba(H_(2)O)_(n)(NO_(3))2-ads)=0.02‰.Overall,there were almost no Ba isotope fractionations during leaching.Although the Ba isotope fractionation can be magnified by the Rayleigh fractionation process in purification,the difference inδ137/134Ba between the initial and final stages did not exceed0.060‰(or 0.045‰)when leaching the standard sample with HCl or HNO_(3),which is equal to or less than the accuracy of Ba isotopic analysis.At a common yield of89.75%,Ba isotopic fractionation induced by incomplete recovery was 0.015‰for HCl(or 0.011‰for HNO_(3)).Finally,if the influence of an incomplete recovery on theδ137/134Ba determination needs to be ignored,the recovery is suggested to be not less than 67%for HCl(or 46%for HNO_(3)). 展开更多
关键词 Ion exchange BARIUM equilibrium isotopic fractionation First-principles calculations Rayleigh fractionation
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FMLSMETHODOFPARAMETERESTIMATIONANDITSAPPLICATIONTOHEAT┐EXCHANGERIDENTIFICATION
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作者 Zhou Bo Tu Zhiying Department of Automatic Control, NUAA29 Yudao Street, Nanjing 210016, P. R. China Chongqing University, Chongqing 630044,P.R.China) 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 1996年第1期87-94,共8页
Using the inversion of the auto correlation function Toeplitz matrix of pseudo random binary sequence (PRBS) derived in this paper and the theorem of partitioned matrix inversion, a fast multistage least squares (FM... Using the inversion of the auto correlation function Toeplitz matrix of pseudo random binary sequence (PRBS) derived in this paper and the theorem of partitioned matrix inversion, a fast multistage least squares (FMLS) method is developed. Its performances are theoretically analyzed and digital simulation is made to compare FMLS with multistage least squares (MSLS), correlation least squares(COR LS) and LS for their computer speed and identification accuracy. Finally, FMLS is applied to identifying the heat excharger dynamics. It is shown that FMLS is a good and effective identification technique. 展开更多
关键词 systems identification least squares methods parameter estimations fast multistage least squares heat exchanger
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