期刊文献+
共找到277篇文章
< 1 2 14 >
每页显示 20 50 100
Innovative Exploration and Research on International Exchange and Cooperation Mechanisms under the Background of Hainan Free Trade Port
1
作者 Xiaochao Yao 《Proceedings of Business and Economic Studies》 2024年第1期150-154,共5页
In order to explore and foster innovation in international exchange and cooperation,this study focuses on the background of the construction of the Hainan Free Trade Port.It delves into the current development status,... In order to explore and foster innovation in international exchange and cooperation,this study focuses on the background of the construction of the Hainan Free Trade Port.It delves into the current development status,characteristic demands,and potential challenges of its international exchange and cooperation mechanisms.Through a comprehensive analysis of relevant cases,survey questionnaires,and literature,this study aims to provide feasible innovative models and recommendations to promote the sustained development of the Hainan Free Trade Port in the field of international exchange and cooperation,injecting new vitality into China’s economic globalization.This exploration contributes to a deeper understanding of the development of free trade ports and provides insights and references for other countries and regions. 展开更多
关键词 free trade port International exchange Cooperation mechanism
下载PDF
Miniature quad-channel spin-exchange relaxation-free magnetometer for magnetoencephalography 被引量:6
2
作者 Jian-Jun Li Peng-Cheng Du +3 位作者 Ji-Qing Fu Xu-Tong Wang Qing Zhou Ru-Quan Wang 《Chinese Physics B》 SCIE EI CAS CSCD 2019年第4期145-149,共5页
A miniature quad-channel optically pumped atomic magnetometer(OPM) has been developed based on the spinexchange relaxation-free(SERF) mechanism. With a vapor cell of size 8 mm×8 mm×8 mm, we have incorporated... A miniature quad-channel optically pumped atomic magnetometer(OPM) has been developed based on the spinexchange relaxation-free(SERF) mechanism. With a vapor cell of size 8 mm×8 mm×8 mm, we have incorporated four SERF magnetometer channels, which provides sufficient spatial resolution for magnetoencephalography(MEG). The four channels share the same laser beam for the best cancellation of common mode noise due to laser fluctuations. With gradient measurement, the sensitivities of the four sensors are better than 6 fT/Hz^(1/2), which is also good enough for MEG measurement. The vapor cell is heated to 160℃ by a novel nonmagnetic current-heating structure. Our sensor with high spatial resolution and compact size is particularly suitable for MEG systems. 展开更多
关键词 multi-channel SPIN-exchange relaxation-free optically PUMPED atomic MAGNETOMETER magne-toencephalography
下载PDF
Transverse relaxation determination based on light polarization modulation for spin-exchange relaxation free atomic magnetometer 被引量:4
3
作者 Xue-Jing Liu Ming Ding +3 位作者 Yang Li Yan-Hui Hu Wei Jin Jian-Cheng Fang 《Chinese Physics B》 SCIE EI CAS CSCD 2018年第7期276-280,共5页
A transverse relaxation determination of spin-exchange relaxation free (SERF) magnetometer based on polarization modulation technique is proposed. Compared with the radio-frequency (RF) excitation and light intens... A transverse relaxation determination of spin-exchange relaxation free (SERF) magnetometer based on polarization modulation technique is proposed. Compared with the radio-frequency (RF) excitation and light intensity excitation meth- ods used in SERF magnetometer, the light polarization modulation method has a high stability in low-frequency range, which indicates a more accurate transverse relaxation measurement. 展开更多
关键词 spin-exchange relaxation free (SERF) magnetometer LINEWIDTH optical polarization modulation
下载PDF
Spin dynamics of the potassium magnetometer in spin-exchange relaxation free regime 被引量:2
4
作者 伏吉庆 杜鹏程 +1 位作者 周庆 王如泉 《Chinese Physics B》 SCIE EI CAS CSCD 2016年第1期436-439,共4页
The laser-pumped potassium spin-exchange relaxation free (SERF) magnetometer is the most sensitive detector of magnetic field and has many important applications. We present the experimental results of our potassium... The laser-pumped potassium spin-exchange relaxation free (SERF) magnetometer is the most sensitive detector of magnetic field and has many important applications. We present the experimental results of our potassium SERF magne- tometer. A pump-probe approach is used to identify the unique spin dynamics of the atomic ensemble in the SERF regime. A single channel sensitivity of 8 f.THz-1/2 is achieved with our SERF magnetometer. 展开更多
关键词 Larmor process spin-exchange relaxation free magnetometer atomic magnetometer
下载PDF
Sister chromatid exchange and DNA damage in human lymphocytes induced by air-dust in Lanzhou City: involvement in free radicals
5
作者 Zheng Rongliang, Wang Xiaoxuan, Hu Huping Fan Zhanru and Zhang YuzhanLaboratory of Biophysics,Department of Biology,Lanshou University,Lanshou 730000,China. 《Journal of Environmental Sciences》 SCIE EI CAS CSCD 1991年第2期69-74,共6页
The air-dust samples collected from petro-chemical industrial region in the suburb of Lanzhou and from a certain rural region 64 km away from the city were extracted, with a mixed solvent (benzene: hexane: isopropanol... The air-dust samples collected from petro-chemical industrial region in the suburb of Lanzhou and from a certain rural region 64 km away from the city were extracted, with a mixed solvent (benzene: hexane: isopropanol=7:2:1) for 8 hours. A strong free radical signal at g= 2.00 of air-dust itself and a hyperfine splitting EPR signal of extract from air-dust have been detected. The sister chromatid exchange frequency (SCE) was increased by extracts of both dusts from the industrial region and from the rural region. If a chemical is able to increase SCE up to twice as high as the control, this chemical is considered to be mutagenic and/or carcinogenic. The double SCE frequency concentration is 23 μg/ml for the dust extract obtained from the industrial region and 47μg/ml for that from the rural region. Extracts were able to damage to DNA template. Results indicated that the mutagenicity and/or carcinogenicity of the extracts obtained from the petro-chemical industrial region were stronger than that of the extracts from the rural region. 展开更多
关键词 air-dust sister chromatid exchange DNA damage free radical.
下载PDF
Numerical Computing for a Class of Free Multipoint Boundary Value Problem of O.D.E in the Intervention of Exchange Rate
6
作者 赵连霞 朱正佑 秦成林 《Journal of Shanghai University(English Edition)》 CAS 2005年第4期320-325,共6页
In this paper by means of generalized shooting method and homotopy technique a numerical method was given for computing free multipoint boundary value problem proposed in the intervention of exchange rate by Cadenilla... In this paper by means of generalized shooting method and homotopy technique a numerical method was given for computing free multipoint boundary value problem proposed in the intervention of exchange rate by Cadenillas and Femaado Zapatero. A numerical example was given for illustrating the validity of this method. 展开更多
关键词 exchange rate interventon nonlinear ordinary differential equation free boundary value problem generalized shooting method
下载PDF
In-situ measurement of magnetic field gradient in a magnetic shield by a spin-exchange relaxation-free magnetometer
7
作者 房建成 王涛 +2 位作者 张红 李阳 蔡洪炜 《Chinese Physics B》 SCIE EI CAS CSCD 2015年第6期253-258,共6页
A method of measuring in-situ magnetic field gradient is proposed in this paper. The magnetic shield is widely used in the atomic magnetometer. However, there is magnetic field gradient in the magnetic shield, which w... A method of measuring in-situ magnetic field gradient is proposed in this paper. The magnetic shield is widely used in the atomic magnetometer. However, there is magnetic field gradient in the magnetic shield, which would lead to additional gradient broadening. It is impossible to use an ex-situ magnetometer to measure magnetic field gradient in the region of a cell, whose length of side is several centimeters. The method demonstrated in this paper can realize the in-situ measurement of the magnetic field gradient inside the cell, which is significant for the spin relaxation study. The magnetic field gradients along the longitudinal axis of the magnetic shield are measured by a spin-exchange relaxation-free (SERF) magnetometer by adding a magnetic field modulation in the probe beam's direction. The transmissivity of the cell for the probe beam is always inhomogeneous along the pump beam direction, and the method proposed in this paper is independent of the intensity of the probe beam, which means that the method is independent of the cell's transmissivity. This feature makes the method more practical experimentally. Moreover, the AC-Stark shift can seriously degrade and affect the precision of the magnetic field gradient measurement. The AC-Stark shift is suppressed by locking the pump beam to the resonance of potassium's D1 line. Furthermore, the residual magnetic fields are measured with σ+- and σ--polarized pump beams, which can further suppress the effect of the AC-Stark shift. The method of measuring in-situ magnetic field gradient has achieved a magnetic field gradient precision of better than 30 pT/mm. 展开更多
关键词 spin-exchange relaxation-free atomic magnetometer magnetic field gradient magnetic shield AC-Stark shift
下载PDF
新疆高校图书馆服务自贸试验区文化交流与合作的策略研究
8
作者 陈琳 陈英杰 《文化创新比较研究》 2024年第27期91-95,共5页
该文深入探讨了新疆高校图书馆在自贸试验区文化交流与合作中的功能与影响。新疆作为古丝绸之路的重要驿站,在“一带一路”倡议的推动下,其文化交流与合作的地位愈加凸显。特别是自贸试验区的设立,不仅打开了新疆对外开放的新局面,也为... 该文深入探讨了新疆高校图书馆在自贸试验区文化交流与合作中的功能与影响。新疆作为古丝绸之路的重要驿站,在“一带一路”倡议的推动下,其文化交流与合作的地位愈加凸显。特别是自贸试验区的设立,不仅打开了新疆对外开放的新局面,也为新疆高校图书馆在文化交流与合作中发挥作用提供了更为广阔的舞台。新疆高校图书馆作为文化传承和知识创新的重要基地,在自贸试验区中扮演了多重角色。这些功能的发挥对自贸试验区乃至整个新疆地区的经济、文化和社会发展产生了积极影响:一方面,文化交流与合作促进了知识的传播和创新,为地方经济发展注入了新的活力;另一方面,图书馆的活动增强了不同民族和文化间的相互理解和尊重,有助于构建和谐稳定的社会环境。 展开更多
关键词 新疆高校图书馆 自贸试验区 文化交流与合作 学术支撑 服务平台 推广策略
下载PDF
质子交换膜燃料电池性能优化控制 被引量:2
9
作者 胡杰 徐泽俊 +3 位作者 岳肖 李昊 袁春 宾洋 《中国电机工程学报》 EI CSCD 北大核心 2024年第1期395-406,I0033,共13页
质子交换膜燃料电池(proton exchange membrane fuel cell,PEMFC)的热管理,是影响PEMFC安全、稳定、高效运行的核心关键因素。该文在分析PEMFC热管理子系统的结构,以及关键组成部件(包括空气压缩机、冷却液循环泵和冷却风扇)的工作原理... 质子交换膜燃料电池(proton exchange membrane fuel cell,PEMFC)的热管理,是影响PEMFC安全、稳定、高效运行的核心关键因素。该文在分析PEMFC热管理子系统的结构,以及关键组成部件(包括空气压缩机、冷却液循环泵和冷却风扇)的工作原理基础上,首先搭建耦合热管理子系统的PEMFC非线性仿真模型,进一步将其简化处理得到用于控制的线性模型;在此基础上,设计基于卡尔曼滤波的状态观测器,以实现对状态和不可测量扰动的估计,从而消除模型稳态误差;随后设计目标计算器,以净输出功率跟踪误差最小化和系统效率最大化为目标,对PEMFC系统工作状态进行优化;进而基于线性控制模型,设计无偏显式模型预测控制(offset-free explicit model predictive control,offset-free EMPC),对优化工作状态进行跟踪控制;最后,搭建一个软件在环(softwareintheloop,Si L)测试平台,通过与传统MPC控制策略的仿真结果对比可得,无偏EMPC控制策略可以显著将净输出功率的平均跟踪误差绝对值从344.29W减小到82.19W,系统效率从40.32%提升到46.56%,算法平均单步计算耗时从26ms降低到11.8ms,并且可以约束PEMFC系统运行在稳定和安全的工况。 展开更多
关键词 质子交换膜燃料电池 系统热管理 净输出功率跟踪 效率最优化 无偏显式模型预测控制
下载PDF
基于遗传算法的磁自抑制加热器的设计与优化
10
作者 刘彦彦 祝静 +3 位作者 谭志成 刘晓飞 王帅 祝连庆 《半导体光电》 CAS 北大核心 2024年第4期575-583,共9页
超低磁噪声(0~10 nT)的碱金属加热技术是无自旋交换弛豫原子磁力仪实现超高灵敏度的关键,文章提出一种基于遗传算法的磁自抑制加热器多目标优化设计方法。该方法基于毕奥-萨伐尔定律推导目标函数新模型,优化的目标包括加热丝的长度、宽... 超低磁噪声(0~10 nT)的碱金属加热技术是无自旋交换弛豫原子磁力仪实现超高灵敏度的关键,文章提出一种基于遗传算法的磁自抑制加热器多目标优化设计方法。该方法基于毕奥-萨伐尔定律推导目标函数新模型,优化的目标包括加热丝的长度、宽度、厚度和电流方向4类(18个)参数,以此获取加热器最佳磁自抑制性能。利用有限元分析方法,仿真分析了目标区域的磁场分布和温度分布,结果表明:加热器在目标区域的中心区域产生0.02 nT/mA的平均磁场和180.34℃的平均温度。实验测试结果显示:目标区域的磁通密度取值在0.13 nT/mA和0.14 nT/mA范围内,这表明加热器的磁场自抑制性能较好。该研究有助于进一步提高原子磁力仪的性能。 展开更多
关键词 无自旋交换弛豫原子磁力仪 磁自抑制 遗传算法 毕奥-萨伐尔定律
下载PDF
某海上采油平台天然气压缩机换热器免拆装清洗改造
11
作者 曹天兵 《当代化工研究》 CAS 2024年第9期163-165,共3页
某海上采油平台天然气压缩机的换热器为管壳式换热器,换热盘管为“U形”。目前,换热器清洗作业需要拆卸封头同时抽芯更换高压密封垫片,作业工作量大、危险性高、消耗资金多。本文通过设计、改造当前换热器冷却介质海水的流程,实现在不... 某海上采油平台天然气压缩机的换热器为管壳式换热器,换热盘管为“U形”。目前,换热器清洗作业需要拆卸封头同时抽芯更换高压密封垫片,作业工作量大、危险性高、消耗资金多。本文通过设计、改造当前换热器冷却介质海水的流程,实现在不拆装换热器封头的情况下通过导通海水反洗流程完成换热器的清洗。 展开更多
关键词 管壳式换热器 海水流程改造 免拆装 清洗
下载PDF
中国自贸区建设对人民币国际化的影响研究
12
作者 温少爽 《中国商论》 2024年第19期17-21,共5页
近年来,中国政府积极推进自由贸易区建设,凸显了自贸区在促进金融高水平开放方面的巨大潜力。然而,自贸区建设对人民币国际化的直接影响在学术界尚未得到充分探讨。本文基于2009—2023年的面板数据,研究了中国自由贸易区对人民币国际化... 近年来,中国政府积极推进自由贸易区建设,凸显了自贸区在促进金融高水平开放方面的巨大潜力。然而,自贸区建设对人民币国际化的直接影响在学术界尚未得到充分探讨。本文基于2009—2023年的面板数据,研究了中国自由贸易区对人民币国际化的影响。研究发现,自贸区的设立与跨境人民币结算贸易额、跨境人民币结算累计对外直接投资额以及人民币占全球储备货币份额之间存在正相关关系。这表明自贸区为企业提供了更便利的贸易和投资环境,降低了跨境交易成本,提高了人民币在国际市场上的使用率。自贸区通过推动人民币在国际贸易和投资中的流通和使用,有助于增强人民币的国际地位,推进人民币国际化。这一研究结果为深化人民币国际化的路径和机制提供了理论和实证支持。 展开更多
关键词 自贸区 人民币国际化 跨境结算 对外直接投资 外汇储备
下载PDF
海南自贸港发展离岸贸易的政策研究
13
作者 王翚 王哲轩 《西南石油大学学报(社会科学版)》 2024年第4期30-39,共10页
离岸贸易作为外贸活动中具有高附加值的新型贸易方式,在海南自贸港封关运作之际,着力推进离岸贸易新业态的发展势在必行。首先对离岸贸易的概念、特征与类型进行系统梳理,认为离岸贸易服务体系的完善、税赋水平的降低、外汇管制的宽松... 离岸贸易作为外贸活动中具有高附加值的新型贸易方式,在海南自贸港封关运作之际,着力推进离岸贸易新业态的发展势在必行。首先对离岸贸易的概念、特征与类型进行系统梳理,认为离岸贸易服务体系的完善、税赋水平的降低、外汇管制的宽松以及金融市场监管体制的完善是持续推进离岸贸易发展的重要条件。然后从政策角度出发,参考现有国际自贸港发展离岸贸易的成功经验来可视化政策效果,最后建议海南自贸港应更加注重离岸贸易与提升政府服务水平、优化营商环境和加强专业监管三个目标相结合,应以打造优秀的离岸贸易综合服务平台为核心,紧紧围绕税收制度的设计、外汇管理模式的变革、金融监管方式的完善等来建立政策框架以加快离岸贸易发展步伐。 展开更多
关键词 海南自贸港 离岸贸易 综合服务平台 税制环境 外汇管制 金融监管
下载PDF
绿色节能型黄金电解精炼技术研究与应用
14
作者 倪迎瑞 李海涛 +4 位作者 熊鹏程 张圣杰 闵丁丁 宁创路 王轶博 《黄金》 CAS 2024年第5期54-56,共3页
针对传统黄金电解精炼过程存在的高污染、高损耗、高能耗和高成本问题,引入绿色、环保的离子交换膜电解技术、粉末冶金技术、湿法无氨工艺和Ag-Ti双金属复合材料,实现了黄金电解精炼从铸板、造液、电解到废电解液净化、金阳极泥处理整... 针对传统黄金电解精炼过程存在的高污染、高损耗、高能耗和高成本问题,引入绿色、环保的离子交换膜电解技术、粉末冶金技术、湿法无氨工艺和Ag-Ti双金属复合材料,实现了黄金电解精炼从铸板、造液、电解到废电解液净化、金阳极泥处理整个过程的提质降耗。该技术的成功应用使得总金回收率从99.85%提高到99.95%,银回收率从66%提高到99%,能耗降低了约30%,从源头上杜绝了氮氧化物的产生及氨水的使用,为企业带来了显著的经济效益和环境效益。 展开更多
关键词 离子交换膜电解技术 湿法无氨工艺 复合材料 电解精炼 提质降耗
下载PDF
浅析板管蒸发冷却式无霜空气源热泵及其设计应用
15
作者 黄运松 梁志辉 +3 位作者 李志明 张锦俊 麦嘉强 孙少华 《暖通空调》 2024年第8期115-121,37,共8页
在常规板管蒸发冷却式冷水机组设计的基础上,借鉴了热源塔热泵系统使用防冻液喷淋的防冻措施原理,将其应用在板管蒸发冷却式冷热水机组上,并对板管蒸发式换热器及系统进行设计改进,使其适用于冬季制热工况,从而形成板管蒸发冷却式无霜... 在常规板管蒸发冷却式冷水机组设计的基础上,借鉴了热源塔热泵系统使用防冻液喷淋的防冻措施原理,将其应用在板管蒸发冷却式冷热水机组上,并对板管蒸发式换热器及系统进行设计改进,使其适用于冬季制热工况,从而形成板管蒸发冷却式无霜空气源热泵机组。机组夏季采用板管蒸发式换热器作为冷凝器,相比于空气源热泵降低了冷凝温度,提高了系统的性能系数。冬季使用防冻液喷淋,设备运行无除霜循环,系统供热稳定,大大提高了室内侧的热舒适性。试验研究了不同溶液再生方式下的机组性能,结果表明:利用过冷热再生模式进行溶液再生时机组性能最优,在制热量不衰减的情况下性能系数仅下降了2.5%~5.1%。机组适用于夏热冬冷地区及部分纬度较低的寒冷地区。 展开更多
关键词 空气源热泵 板管蒸发冷却式换热器 溶液再生 无霜 溶液喷淋 过冷热再生 夏热冬冷地区
下载PDF
冰箱内外压差变化对冰箱性能影响研究
16
作者 崔培培 魏邦福 +2 位作者 邓萍萍 陈开松 余涛 《家电科技》 2024年第2期98-102,共5页
冰箱制冷运行过程中存在“呼吸效应”,箱内外气体会随“呼吸效应”产生热质交换。通过压差实验的方法,研究单循环风冷冰箱制冷过程中箱内风机、风门、压缩机开停切换,冰箱状态变化等对箱内外压差形成机制影响。经验证:通过封闭化霜排水... 冰箱制冷运行过程中存在“呼吸效应”,箱内外气体会随“呼吸效应”产生热质交换。通过压差实验的方法,研究单循环风冷冰箱制冷过程中箱内风机、风门、压缩机开停切换,冰箱状态变化等对箱内外压差形成机制影响。经验证:通过封闭化霜排水管,可改变外界高温高湿气体进入箱体内的途径,增大冷藏室进气量,延长外界气体进入箱内的路径,从而提升冷藏室的相对湿度,对蔬菜水果保鲜有利,同时节能减排。 展开更多
关键词 气压差 冰箱性能 风冷冰箱 呼吸效应 热质交换
下载PDF
Manufacture of Boron-free Magnesia with High Purity from Residual Brine 被引量:5
17
作者 FaQiangLI BaoPingLING PeiHuaMA 《Chinese Chemical Letters》 SCIE CAS CSCD 2004年第11期1353-1356,共4页
A novel method for removing boron with ion exchange resin from residual brines to manufacture boron-free magnesia is described. The concentration of boron in the target magnesia manufactured thereby from Qinghai salt... A novel method for removing boron with ion exchange resin from residual brines to manufacture boron-free magnesia is described. The concentration of boron in the target magnesia manufactured thereby from Qinghai salt lakes is lower than 5 mg/g, and the typical D50 size of product is 10.625 mm. 展开更多
关键词 MAGNESIA boron-free salt lake brine ion exchange resin.
下载PDF
The Pursuit of Fallacy in Density Functional Theory: The Quest for Exchange and Correlation, the Rigorous Treatment of Exchange in the Kohn-Sham Formalism and the Continuing Search for Correlation
18
作者 A. Gonis 《World Journal of Condensed Matter Physics》 2014年第3期200-225,共26页
As pointed out in the paper preceding this one, in the case of functionals whose independent variable must obey conditions of integral normalization, conventional functional differentiation, defined in terms of an arb... As pointed out in the paper preceding this one, in the case of functionals whose independent variable must obey conditions of integral normalization, conventional functional differentiation, defined in terms of an arbitrary test function, is generally inapplicable and functional derivatives with respect to the density must be evaluated through the alternative and widely used limiting procedure based on the Dirac delta function. This leads to the determination of the rate of change of the dependent variable with respect to its independent variable at each isolated pair, , that may not be part of a functional (a set of ordered pairs). This extends the concept of functional derivative to expectation values of operators with respect to wave functions leading to a density even if the wave functions (and expectation values) do not form functionals. This new formulation of functional differentiation forms the basis for the study of the mathematical integrity of a number of concepts in density functional theory (DFT) such as the existence of a universal functional of the density, of orbital-free density functional theory, the derivative discontinuity of the exchange and correlation functional and the extension of DFT to open systems characterized by densities with fractional normalization. It is shown that no universal functional exists but, rather, a universal process based only on the density and independent of the possible existence of a potential, leads to unique functionals of the density determined through the minimization procedure of the constrained search. The mathematical integrity of two methodologies proposed for the treatment of the Coulomb interaction, the self-interaction free method and the optimized effective potential method is examined and the methodologies are compared in terms of numerical calculations. As emerges from this analysis, the optimized effective potential method is found to be numerically approximate but formally invalid, contrary to the rigorously exact results of the self-interaction-free method. 展开更多
关键词 DENSITY FUNCTIONAL THEORY Variational Properties of DENSITY FUNCTIONAL THEORY Self-Interaction Error Optimized Effective Potential FUNCTIONAL DERIVATIVE Parametric DERIVATIVE FUNCTIONAL Rate of Change DERIVATIVE Discontinuity Orbital-free DENSITY FUNCTIONAL THEORY exchange and CORRELATION FUNCTIONAL
下载PDF
SERF原子自旋惯性测量检测误差分析及抑制
19
作者 邢力 全伟 +2 位作者 宋天骁 蔡庆中 叶文 《北京航空航天大学学报》 EI CAS CSCD 北大核心 2023年第9期2345-2350,共6页
在无自旋交换弛豫(SERF)原子自旋惯性测量装置中,检测系统的性能是决定输出信号灵敏度和稳定性极限的关键因素。为有效抑制SERF原子自旋惯性测量的低频随机噪声,在横向电子自旋极化率稳态解和旋光角表达式的基础上,建立检测相关的输出... 在无自旋交换弛豫(SERF)原子自旋惯性测量装置中,检测系统的性能是决定输出信号灵敏度和稳定性极限的关键因素。为有效抑制SERF原子自旋惯性测量的低频随机噪声,在横向电子自旋极化率稳态解和旋光角表达式的基础上,建立检测相关的输出信号误差机理模型,明确了检测系统影响最终测量信号噪声的主要因素。研究结果表明:检测光入射气室时的初始光强作为信号背景直接引起刻度系数的波动而非作用于电子自旋,而检测光的非理想线偏振导致电子自旋产生横向抽运效果和横向光频移作用,从而引入测量误差。针对检测系统影响测量信号噪声的主要参数,设计了参数优化路径:先通过优化检测光频率,提高惯性测量刻度系数,后通过检测光功率的优化,减小横向抽运效应、横向光频移作用及检测光背景波动。实验表明:通过对比输出信号的Allan方差,优化后SERF原子自旋惯性测量的零偏不稳定性减小了1.8倍,速率斜坡噪声系数从0.124 (°)/h^(2)减小至0.041 (°)/h^(2),达到了抑制测量信号低频随机噪声的效果。 展开更多
关键词 无自旋交换弛豫 惯性测量 检测系统 误差机理 横向抽运效应 横向光频移 低频随机噪声
下载PDF
光泵磁力计-脑磁图的应用研究进展
20
作者 姬梦岐 施玉杰 +3 位作者 薛志远 钟凡 蒋睿 张军鹏 《中国生物医学工程学报》 CAS CSCD 北大核心 2023年第6期730-739,共10页
脑磁图作为一种无创获取大脑信号的新技术,可精准反映大脑的神经活动,但传统脑磁图设备的低温超导环境与高运维成本限制了这一技术的发展。光泵磁力计作为一种新型的磁场强度检测装置,具有造价成本低、信噪比高、无需低温液氦冷却等诸... 脑磁图作为一种无创获取大脑信号的新技术,可精准反映大脑的神经活动,但传统脑磁图设备的低温超导环境与高运维成本限制了这一技术的发展。光泵磁力计作为一种新型的磁场强度检测装置,具有造价成本低、信噪比高、无需低温液氦冷却等诸多优势,有望助推脑磁图技术广泛应用。在陈述脑磁图概念的基础上,从技术角度说明光泵磁力计-脑磁图系统的实现原理,梳理该系统存在的命名问题,并从神经语音解码、脑磁源重建、功能神经成像、脑机接口和临床辅助等方面综述了该系统的应用研究进展,总结该新型脑磁图系统独特优势,并展望这种技术的未来潜在应用,最后分析了目前此类研究中可能存在的问题。 展开更多
关键词 脑磁图 光泵磁力计 无自旋交换弛豫 源重建 脑机接口
下载PDF
上一页 1 2 14 下一页 到第
使用帮助 返回顶部