检索结果-南通市图书馆

Pulse chirping effect on controlling the transverse cavity oscillations in nonlinear bubble regime

Chinese Physics B 2017年第2期26卷 313-319页

作者： h Vosoughian Z Riazi h Afarideh G Sarri Laser and Optic Institute Nuclear Science and Technology Research Institute Tehran Iran physics and Accelerator School Nuclear Science and Technology Research Institute Tehran Iran Department of Energy Engineering and Physics Amirkabir University of Technology P. O. Box 15875-4413 Tehran Iran School of Mathematics and Physics The Queen's University of Belfast BT7 INN Belfast United Kingdom

The propagation of an intense laser pulse in an under-dense plasma induces a plasma wake that is suitable for the acceleration of electrons to relativistic energies. For an ultra-intense laser pulse which has a longitudinal size shorter than the plasma wavelength, λp, instead of a periodic plasma wave, a cavity free from cold plasma electrons, called a bubble, is formed behind the laser pulse. An intense charge separation electric field inside the moving bubble can capture the electrons at the base of the bubble and accelerate them with a narrow energy spread. In the nonlinear bubble regime, due to localized depletion at the front of the pulse during its propagation through the plasma, the phase shift between carrier waves and pulse envelope plays an important role in plasma response. The carrier–envelope phase（CEP） breaks down the symmetric transverse ponderomotive force of the laser pulse that makes the bubble structure unstable. Our studies using a series of two-dimensional（2D） particle-in-cell（PIC） simulations show that the frequency-chirped laser pulses are more effective in controlling the pulse depletion rate and consequently the effect of the CEP in the bubble regime. The results indicate that the utilization of a positively chirped laser pulse leads to an increase in rate of erosion of the leading edge of the pulse that rapidly results in the formation of a steep intensity gradient at the front of the pulse. A more unstable bubble structure, the self-injections in different positions, and high dark current are the results of using a positively chirped laser pulse. For a negatively chirped laser pulse, the pulse depletion process is compensated during the propagation of the pulse in plasma in such a way that results in a more stable bubble shape and therefore, a localized electron bunch is produced during the acceleration process. As a result, by the proper choice of chirping, one can tune the number of self-injected electrons, the size of accelerated bunch

关键词： bubble regime plasma wake field positively chirped laser pulse

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Comment on 'Mathematical structure of the three-dimensional (3D) Ising model'

引用

Chinese Physics B 2013年第8期22卷 356-360页

作者： Jacques h. h. Perk Department of Physics Oklahoma State UniversityStillwater OK 74078-3072 USA

The review paper by Zhang Zhi-Dong （Zhang Z D 2013 Chin. Phys. B 22 030513, arXiv：1305.2956） contains many errors and is based on several earlier works that are equally wrong.

关键词： Ising model Lie algebra series analysis thermodynamic limit

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Quantum correlations and optical effects in a quantum-well cavity with a second-order nonlinearity

引用

Communications in Theoretical Physics 2021年第11期73卷 93-101页

作者： h Jabri higher Institute of Biotechnology of Beja University of JendoubaBeja 9000.Tunisia

In this paper,we investigate the photon correlations and the statistical properties of light produced by an optical cavity with an embedded quantum well interacting with squeezed *** show that the squeezed source substantially improves the intensity of the emitted light and generates a narrowing and a duplication of the spectrum *** a strong dependence on frequency detuning,the cavity produces considerably squeezed radiation,and perfect squeezing is predicted for weak light–matter ***,the system under consideration presents a bunching effect of the transmitted radiation resulting from weak pumping of the coherent *** results obtained may have potential applications in the fields of very accurate measurement and quantum computing.

关键词： quantum-well cavity second-order nonlinearity quantum fluctuations nonclassical effects

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Calculation of the Specific heats for the Ⅱ—Ⅲ and Ⅱ—Ⅳ Phase transitions in Nh4I

引用

Chinese Physics Letters 2003年第1期20卷 35-38页

作者： h.Yurtseven h.Kaya Departmentofphysics IstanbulTechnicalUniversityMaslakIstanbulTurkey

This study gives our calculation for the specific heats CVI due to an Ising model using the observed CP data for the II-III and II-IV phase transitions in Nh4I. By fitting to the CP data we determine the values of the critical exponent for the pressure of 0.14 GPa (II-III phase transition) and for the pressures of 0.75, 1.35 and 1.97 GPa (II-IV phase transition) in Nh4I. Our exponent values are close to the predicted values of the specific heat in a three-dimensional Ising model. Our calculated CVI are in good agreement with the experimental CP for Nh4I in most cases.

关键词： Specific heat

来源：

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

Mechanical and microstructural characterization of Al7075/SiC nanocomposites fabricated by dynamic compaction

引用

International Journal of Minerals,Metallurgy and Materials 2014年第3期21卷 295-303页

作者： A.Atrian G.h.Majzoobi M.h.Enayati h.Bakhtiari Mechanical Engineering Department Bu-Ali Sina University Department of Materials Engineering Isfahan University of Technology

This paper describes the synthesis of Al7075 metal matrix composites reinforced with SiC, and the characterization of their microstructure and mechanical behavior. The mechanically milled Al7075 micron-sized powder and SiC nanoparticles are dynamically compacted using a drop hammer device. This compaction is performed at different temperatures and for various volume fractions of SiC nanoparticles. The relative density is directly related to the compaction temperature rise and indirectly related to the content of SiC nanoparticle reinforcement, respectively. Furthermore, increasing the amount of SiC nanoparticles improves the strength, stiffness, and hardness of the compacted specimens. The increase in hardness and strength may be attributed to the inherent hardness of the nanoparticles, and other phenomena such as thermal mismatch and crack shielding. Nevertheless, clustering of the nanoparticles at aluminum particle boundaries make these regions become a source of concentrated stress, which reduces the load carrying capacity of the compacted nanocomposite.

关键词： nanocomposites metallic matrix composites silicon carbide nanoparticles compaction

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Solid-State Interfacial Reaction between Eutectic Au-Ge Solder and Cu/Ni(P)/Au Metalized Ceramic Substrate and Its Suppression

引用

Journal of Materials Science & Technology 2015年第5期31卷 445-452页

作者： F.Q.Lang h.Yamaguchi h.Nakagawa h.Sato Advanced Power Electronics Research Center(ADPERC) National Institute of Advanced Industrial Science and Technology(AIST).Central 21-1-1UmezonoTsukubaIbaraki 305-8568.Japan

Eutectic Au-12 Ge solder was employed to bond the SiC power devices to a Si3N4/Cu/Ni（P）/Au multilayered *** high-temperature reliability of the bond was investigated in detail at 200,250,300 and 330 ℃,*** and Ni5Ge3intermetallic compounds（IMCs） were identified at the Au-12Ge/Ni（P） interface by micro X-ray diffraction（μXRD） and scanning electron microscopy（SEM）equipped with energy dispersive X-ray analysis（EDX）.The growth of the Ni-Ge IMCs was dominated by Ni5Ge3layer,which formed at the Ni5Ge3/NiGe interface by outward diffusion of Ni from the Ni（P） *** activation energy of the total Ni-Ge IMCs growth was 66 kJ/*** shear strength of the bond was tested at both 25 ℃ and the aging temperatures,*** shear strength decreased slightly after aging at 200 and 250 ℃.The shear strength tested at 250 ℃ was 46 MPa after aging at 250 ℃ for 3000 *** shear strength aged at 300 and 330 ℃ rapidly decreased with aging time due to the rapid growth of the *** slow down the interfacial reaction between the high temperature solder and the Ni（P）layer,an approximately 200 nm-thick Ta/TaN/Ta new diffusion barrier（DB） was deposited on the *** by transmission electron microscopy（TEM） equipped with EDX,reveals that the Ta/TaN/Ta DB was bonded well to the Ni（P） layer and the *** temperature storage test at 330 ℃ for1500 h reveals that the bond of the SiC devices maintained its high shear strength of approximately56 MPa without *** new DB effectively suppressed the interfacial reaction between the Au-12 Ge solder and the Ni（P） layer of the substrate.

关键词： high-temperature solder Interfacial reaction Activ

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Numerical Solution of the Asymmetric Water Impact of A Wedge in Three Degrees of Freedom

引用

China Ocean Engineering 2013年第3期27卷 313-322页

作者： h. Ghazizade-Ahsaee A. h. Nikseresht Faculty of Mechanical & Aerospace Engineering Shiraz University of Technology

Impact problems associated with water entry have important applications in various aspects of naval architecture and ocean engineering. Estimation of hydrodynamic impact forces especially during the first instances after the impact is very important and is of interest. Since the estimation of hydrodynamic impact load plays an important role in safe design and also in evaluation of structural weight and costs, it is better to use a reliable and accurate prediction method instead of a simple estimation resulted by analyzing methods. In landing of flying boats, some phenomena such as weather conditions and strong winds can cause asymmetric instead of symmetric descent. In this paper, a numerical simulation of the asymmetric impact of a wedge, as the step of a flying boat, considering dynamic equations in two-phase flow is taken into account. The dynamic motion of the wedge in two-phase flow is solved based on finite volume method with volume of fluid （VOF） scheme considering dynamic equations. Then the effects of different angles of impact and water depth on the velocity change and slamming forces in an asymmetric impact are investigated. The comparison between the simulation results and experimental data verifies the accuracy of the method applied in the present study.

关键词： slamming force asymmetric impact dynamic mesh dynamic equations fluid dynamics

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The sexually dimorphic expression of glutamate transporters and their implication in pain after spinal cord injury

引用

Neural Regeneration Research 2025年第11期20卷 3317-3329页

作者： Jennifer M.Colón-Mercado Aranza I.Torrado-Tapias Iris K.Salgado Jose M.Santiago Samuel E.Ocasio Rivera Dina P.Bracho-Rincon Luis h.Pagan Rivera Jorge D.Miranda Department of Physiology University of Puerto RicoMedical Sciences CampusSan JuanPRUSA National Institutes of health National Human Genome Research InstituteBethesdaMDUSA Universidad Central del Caribe School of MedicineBayamónPRUSA University of Puerto Rico Carolina CampusCarolinaPRUSA Institute of Neurobiology San JuanPRUSA

In addition to the loss of motor function,~60% of patients develop pain after spinal cord *** cellular-molecular mechanisms are not well understood,but the data suggests that plasticity within the rostral,epicenter,and caudal penumbra of the injury site initiates a cellularmolecular interplay that acts as a rewiring mechanism leading to central neuropathic *** can lead to the formation of new connections triggering abnormal sensory *** excitatory glutamate transporters are responsible for the reuptake of extracellular glutamate which makes them a critical target to prevent neuronal hyperexcitability and *** previous studies showed a sexually dimorphic therapeutic window for spinal cord injury after treatment with the selective estrogen receptor modulator *** this study,we investigated the anti-allodynic effects of tamoxifen in male and female rats with spinal cord *** hypothesized that tamoxifen exerts anti-allodynic effects by increasing the expression of glutamate transporters,leading to reduced hyperexcitability of the secondary neuron or by decreasing aberrant *** and female rats received a moderate contusion to the thoracic spinal cord followed by subcutaneous slow-release treatment of tamoxifen or matrix pellets as a control(placebo).We used von Frey monofilaments and the“up-down method”to evaluate mechanical *** treatment decreased allodynia only in female rats with spinal cord injury revealing a sexdependent *** expression profile of glutamatergic transporters(excitatory amino acid transporter 1/glutamate aspartate transporter and excitatory amino acid transporter 2/glutamate transporter-1)revealed a sexual dimorphism in the rostral,epicenter,and caudal areas of the spinal cord with a pattern of expression primarily on *** rodents showed a significantly higher level of excitatory amino acid transporter-1 expression while male rodents showed increased

关键词： allodynia central neuropathic pain EAAT-1/GLAST EAAT-2/GLT-1 glutamate transporters selective estrogen receptor modulator sexual dimorphism spinal cord injury trauma

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A modified averaging scheme with application to the secondary hopf bifurcation of a delayed van der Pol oscillator

引用

Acta Mechanica Sinica 2008年第4期24卷 449-454页

作者： Z.h.Wang h.Y.hu Institute of Sciences PLA University of Science and Technology Nanjing 211101 China Institute of Vibration Engineering Research Nanjing University of Aeronautics and Astronautics Nanjing 210016 China

In this paper, a modified averaging scheme is presented for a class of time-delayed vibration systems with slow variables. The new scheme is a combination of the averaging techniques proposed by hale and by Lehman and Weibel, respectively. The averaged equation obtained from the modified scheme is simple enough but it retains the required information for the local nonlinear dynamics around an equilibrium. As an application of the present method, the delay value for which a secondary hopf bifurcation occurs is successfully located for a delayed van der Pol oscillator.

关键词： Time delay ·Secondary hopf bifurcation·The averaging technique van der Pol oscillator

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

GLOBAL OPTIMIZATION OF ThE DIFFERENCE OF TWO INCREASING PLUS-CONVEX-ALONG-RAYS FUNCTIONS

引用

Acta Mathematica Scientia 2020年第6期40卷 1849-1873页

作者： h.ShAhRIARIPOUR h.MOhEBI Department of Mathematics Graduate University of Advanced TechnologyKermanIran Department of Mathematics and Mahani Mathematical Research Center Shahid Bahonar University of KermanP.O.Box:76169133Postal Code:***KermanIran

The theory of increasing and convex-along-rays(ICAR)functions defined on a convex cone in a real locally convex topological vector space X was already well *** this paper,we first examine abstract convexity of increasing plus-convex-along-rays(IPCAR)functions defined on a real normed linear space *** also study,for this class of functions,some concepts of abstract convexity,such as support sets and ***,as an application,we characterize the maximal elements of the support set of strictly IPCAR functions and give optimality conditions for the global minimum of the difference between two IPCAR functions.

关键词： increasing plus-convex-along-rays function support set maximal element global minimum DC-function

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：