检索结果-南通市图书馆

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

采用双脉冲提高谐波谱的谱线密度

物理学报 2009年第3期58卷 1574-1578页

作者：刘硕陈高陈基根朱颀人长春理工大学理学院物理系长春130022 台州学院物理系椒江318000 吉林大学原子与分子物理研究所长春130012

通过计算线偏振双脉冲激光场与一维氢原子模型相互作用产生的高次谐波辐射谱的含时Schrdinger方程.研究发现,选用适宜的双脉冲激光组合可以增加谐波谱的密度,这样的谐波谱特别适合作为产生孤立阿秒脉冲的光源.详细地分析了谐波谱线密度... 详细信息

通过计算线偏振双脉冲激光场与一维氢原子模型相互作用产生的高次谐波辐射谱的含时Schrdinger方程.研究发现,选用适宜的双脉冲激光组合可以增加谐波谱的密度,这样的谐波谱特别适合作为产生孤立阿秒脉冲的光源.详细地分析了谐波谱线密度增加的物理机理,给出不同脉宽与谐波谱线密度增加的关系,从而可以有针对性地控制谐波谱线的疏密程度.

关键词：高次谐波阿秒脉冲双脉冲

在线全文

学校读者我要写书评

暂无评论

拉伸分子高次谐波产生的阿秒控制

原子与分子物理学报 2008年第5期25卷 1101-1105页

作者：陈高陈基根朱颀人长春理工大学理学院物理系长春130022 台州学院物理系椒江318000 吉林大学原子与分子物理研究所长春130012

通过数值求解一维含时薛定谔方程,本文研究了高频阿秒脉冲对拉伸双原子分子模型与低频飞秒激光脉冲相互作用产生高次谐波谱的影响.研究表明,若阿秒脉冲在低频脉冲的第二个光学周期截止处注入时,只第二个平台截止位置IP+5.6UP(IP为电离势... 详细信息

通过数值求解一维含时薛定谔方程,本文研究了高频阿秒脉冲对拉伸双原子分子模型与低频飞秒激光脉冲相互作用产生高次谐波谱的影响.研究表明,若阿秒脉冲在低频脉冲的第二个光学周期截止处注入时,只第二个平台截止位置IP+5.6UP(IP为电离势,UP为有质动力能)附近谐波的效率得到显著提高;若阿秒脉冲的包络峰值处于低频脉冲第三个光学周期T/4(为飞秒激光脉冲的光学周期)附近时,则谐波谱出现了明显的整体抬高现象.对此,本文根据拉伸分子谐波谱的四种产生机制及阿秒脉冲在飞秒激光不同相位注入时的电子电离曲线,对这些谐波谱的结构给出了合理解释.

关键词：高次谐波阿秒脉冲拉伸的双原子分子模型

在线全文

学校读者我要写书评

暂无评论

我国低碳发展的制约因素及其路径选择

西南民族大学学报（人文社会科学版） 2010年第11期31卷 150-154页

作者：陈晓春朱仁崎湖南大学政治与公共管理学院国防科学技术大学信息系统与管理学院湖南大学工商管理学院

在全球能源紧张和气候变暖趋势的大背景下,低碳理念应运而生。作为一个发展中国家,按照相关国际协约,我国不需要承担强制性的减排义务,但作为一个负责任的大国,我国需要在"共同但有区别"原则基础上,实行低碳式发展。低碳式发展不仅是我... 详细信息

在全球能源紧张和气候变暖趋势的大背景下,低碳理念应运而生。作为一个发展中国家,按照相关国际协约,我国不需要承担强制性的减排义务,但作为一个负责任的大国,我国需要在"共同但有区别"原则基础上,实行低碳式发展。低碳式发展不仅是我国应对国际减排压力之策,也是我国实现经济、社会、环境和谐发展的需要。本文在明确低碳发展内涵的基础上,对我国低碳发展面临的制约因素进行了系统分析,探讨了我国低碳发展的路径选择。

关键词：低碳发展低碳技术节能减排清洁发展机制低碳经济

New insight into the origin and evolution of the flora and fauna of Hainan Island, China

在线全文

学校读者我要写书评

暂无评论

Science China Earth Sciences 2025年第1期68卷 52-61页

作者： Hua zhu Center for Integrative Conservation Xishuangbanna Tropical Botanical Garden Chinese Academy of Sciences Yunnan International Joint Laboratory of Southeast Asia Biodiversity Conservation Yunnan Key Laboratory for the Conservation of Tropical Rainforests and Asian Elephants

The origin of the biota of Hainan Island, China, remains a fundamental scientific problem. Comparative studies on the biota, geological tectonics, and paleomagnetism proposed that during the Eocene, Hainan Island connected Vietnam and Guangxi, and then moved to the southeast to reach its present location. This review mainly discusses its biota origin from molecular phylogeny and palaeobotanical research. The formation and evolution of the biological groups of Hainan Island were identified via research on their genomes, phylogeny, and molecular biogeography. This research showed that the genera and species that appeared and diverged early in their evolution(i.e., before the Miocene) can be explained by the land connection between Hainan Island, Vietnam, and Guangxi during the Eocene-Oligocene. According to Southeast Asian tectonic theory, in the Middle Miocene(at about 15 million years ago), Hainan Island had moved to its present position. The population and genetic divergence of species with late divergence times(after 15 Ma) can be reasonably explained by the close proximity(or land connection) between Hainan Island and the Leizhou Peninsula, enabling genetic communication between Hainan Island and the Chinese mainland, but have exceptional cases. Conclusions have been obtained through palaeobotanical studies, showing that in the Eocene-Oligocene period, southwest China and Hainan Island had subtropical vegetation and flora. However, the fossil group in southeast China(in Maoming, near present-day Hainan Island) in the Late Eocene indicated a tropical rainforest vegetation and flora. This suggests that in the Paleogene, Hainan Island may have been located near or on the southwest border of Guangxi and northern Vietnam, rather than in its present location. The floristic division of the flora of Hainan Island basically presents a northeast-southwest inclined distribution pattern. This pattern can be explained by the counterclockwise rotation of Hainan Island during i

关键词： Molecular phylogeny Biogeography Paleobotany Origin of flora and fauna Hainan Island of China

同方期刊数据库

一维联合双原子在组合激光脉冲作用下的超高次谐波发射

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2007年第2期24卷 415-417页

作者：郭福明杨玉军朱颀人吉林大学原子与分子物理研究所长春130012

本文分析了在联合原子方案下高于Ip+3.2Up的超高次谐波发射效率极低的主要因素:除电子间的排斥作用外,更重要的原因乃是在通常情况下外来电子在非母离子中没有布居.据此,提出了一个有效解决这个难题的组合激光脉冲方案,从而将高达Ip+8U... 详细信息

本文分析了在联合原子方案下高于Ip+3.2Up的超高次谐波发射效率极低的主要因素:除电子间的排斥作用外,更重要的原因乃是在通常情况下外来电子在非母离子中没有布居.据此,提出了一个有效解决这个难题的组合激光脉冲方案,从而将高达Ip+8Up的超高次谐波的发射效率提高了三个数量级以上.

关键词：高次谐波联合双原子组合脉冲

Modification of Maxwell model for conductivity prediction of carbon nanotubes-filled polymer composites with tunneling effect

在线全文

学校读者我要写书评

暂无评论

Applied Mathematics and Mechanics(English Edition) 2025年第1期46卷 25-36页

作者： Jue zhu Longyuan LI Ningtao zhu Zhejiang Provincial Engineering Research Center for the Safety of Pressure Vessel and Pipeline Key Laboratory of Impact and Safety Engineering (Ningbo University) Ministry of Education School of Engineering Computing and Mathematics University of Plymouth Xi'an Zhanshi Testing & Engineering Co.Ltd.

Carbon nanotubes(CNTs) have garnered great attention in recent years due to their outstanding electrical, thermal, and mechanical properties. The incorporation of small amounts of CNTs in polymers can substantially improve the sensitivity of the polymer's electrical conductivity. This paper presents a modified Maxwell model to evaluate the electrical conductivity of CNTs-filled polymer composites by introducing a transition zone to account for the tunneling effect. In this modified Maxwell model, the CNTs-filled polymer composite is modeled as a three-phase composite, consisting of a matrix(polymer), inclusions(CNTs), and a transition zone(tunneling zone). The effective electrical conductivity(EEC) of the composite is calculated based on the volume fractions and electrical conductivities of the matrix, inclusions, and transition zone. The model's validity is confirmed through the use of available test data, which demonstrates its capability to accurately capture the nonlinear conductivity behavior observed in CNTs-polymer composites. This study offers valuable insights into the design of high-performance conductive polymer nanocomposites, and enhances the understanding of electrical conduction mechanisms in CNT-dispersed polymer composites.

关键词： Nanoclay

Role of the globus pallidus in motor and non-motor symptoms of Parkinson's disease

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第6期20卷 1628-1643页

作者： Yimiao Jiang Zengxin qi Huixian zhu Kangli Shen Ruiqi Liu Chenxin Fang Weiwei Lou Yifan Jiang Wangrui Yuan Xin Cao Liang Chen qianxing zhuang Department of Physiology School of MedicineNantong UniversityNantongJiangsu ProvinceChina Department of Neurosurgery Huashan HospitalShanghai Medical CollegeFudan UniversityShanghaiChina National Center for Neurological Disorders ShanghaiChina Shanghai Key Laboratory of Brain Function Restoration and Neural Regeneration ShanghaiChina State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Institute of Brain ScienceFudan UniversityShanghaiChina

The globus pallidus plays a pivotal role in the basal ganglia circuit. Parkinson's disease is characterized by degeneration of dopamine-producing cells in the substantia nigra, which leads to dopamine deficiency in the brain that subsequently manifests as various motor and non-motor symptoms. This review aims to summarize the involvement of the globus pallidus in both motor and non-motor manifestations of Parkinson's disease. The firing activities of parvalbumin neurons in the medial globus pallidus, including both the firing rate and pattern, exhibit strong correlations with the bradykinesia and rigidity associated with Parkinson's disease. Increased beta oscillations, which are highly correlated with bradykinesia and rigidity, are regulated by the lateral globus pallidus. Furthermore,bradykinesia and rigidity are strongly linked to the loss of dopaminergic projections within the cortical-basal ganglia-thalamocortical loop. Resting tremors are attributed to the transmission of pathological signals from the basal ganglia through the motor cortex to the cerebellum-ventral intermediate nucleus circuit. The cortico–striato–pallidal loop is responsible for mediating pallidi-associated sleep disorders. Medication and deep brain stimulation are the primary therapeutic strategies addressing the globus pallidus in Parkinson's disease. Medication is the primary treatment for motor symptoms in the early stages of Parkinson's disease, while deep brain stimulation has been clinically proven to be effective in alleviating symptoms in patients with advanced Parkinson's disease,particularly for the movement disorders caused by levodopa. Deep brain stimulation targeting the globus pallidus internus can improve motor function in patients with tremordominant and non-tremor-dominant Parkinson's disease, while deep brain stimulation targeting the globus pallidus externus can alter the temporal pattern of neural activity throughout the basal ganglia–thalamus network. Therefore, the comp

关键词： anxiety basal ganglia bradykinesia deep brain stimulation depression globus pallidus externus globus pallidus internus lateral globus pallidus medial globus pallidus neural circuit Parkinson's disease

在线全文

学校读者我要写书评

暂无评论

高次谐波发射中的超拉曼发射(英文)

原子与分子物理学报 2008年第6期25卷 1323-1327页

作者：刘艳于若飞朱颀人杨玉军吉林大学原子与分子物理研究所长春130012

本文研究了单电子分子离子与强激光场相互作用下的高次谐波发射谱.从光谱中观察到除了存在入射激光频率奇数倍的谐波谱线外,还存在其他频率的超拉曼谱线.在理论上阐明了超拉曼谱线不同于高次谐波谱线的物理产生机制.研究发现当体系初态... 详细信息

本文研究了单电子分子离子与强激光场相互作用下的高次谐波发射谱.从光谱中观察到除了存在入射激光频率奇数倍的谐波谱线外,还存在其他频率的超拉曼谱线.在理论上阐明了超拉曼谱线不同于高次谐波谱线的物理产生机制.研究发现当体系初态为基态和较高激发态的叠加态时能够较清晰的观察到超拉曼谱线,从而说明激发态电子的布居对超拉曼谱线的产生起着关键作用.因此在实验上,制备一个叠加态使得电子从激发态电离,是观察到超拉曼谱线的重要条件.

关键词：超拉曼谱线高次谐波叠加态

在线全文

学校读者我要写书评

暂无评论

相干叠加态高次谐波发射的时间行为分析

原子与分子物理学报 2006年第3期23卷 387-392页

作者：杨玉军池方萍郑长彬朱颀人吉林大学原子与分子物理研究所

本文研究了一维模型分子离子(初态为基态和一个激发束缚态叠加的相干态)在超强超短激光脉冲作用下的谐波发射谱.我们发现在高次谐波谱平台区域出现了周期性的结构变化.我们利用小波变换对谐波谱进行了暂态时间频率分析,结果表明该谐波... 详细信息

本文研究了一维模型分子离子(初态为基态和一个激发束缚态叠加的相干态)在超强超短激光脉冲作用下的谐波发射谱.我们发现在高次谐波谱平台区域出现了周期性的结构变化.我们利用小波变换对谐波谱进行了暂态时间频率分析,结果表明该谐波结构产生的原因是由电离电子返回母离子时与不同束缚态复合而产生的谐波光脉冲之间相干叠加.同时采用半经典计算,对所得到的计算结果进行了分析,验证了我们的结论.

关键词：高次谐波小波变换