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Plasma Science and Technology 2021年第3期23卷 76-81页

作者： Muhammad KHALID Ghufran ULLAH Mohsin KHAN sheraz ahmad Sardar NABI Daud KHAN Depatment of Physics Govermment Post Gaduate College MardanMardan 23200Pakistan Department of Physics Islamia College Peshawar(Public Sector University)Peshawar 25120Pakistan Department of Physics Government Post Graduate College NowsheraNowshera 24100Pakistan

Theoretical investigation of nonlinear electrostatic ion-acoustic cnoidal waves(IACWs) is presented in magnetized electron–positron–ion plasma with nonextensive electrons and Maxwellian positrons. Using reductive perturbation technique, Korteweg–de Vries equation is derived and its cnoidal wave solution is analyzed. For given plasma parameters, our model supports only positive potential(compressive) IACW structures. The effect of relevant plasma parameters(viz., nonextensive parameter q, positron concentration p, temperature ratio σ,obliqueness l3) on the characteristics of IACWs is discussed in detail.

关键词： ion-acoustic cnoidal waves KdV equation q-distribution

Effect of CoSi_2 buffer layer on structure and magnetic properties of Co films grown on Si(001) substrate

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Chinese Physics B 2015年第1期24卷 484-488页

作者：胡泊何为叶军汤进 Syed sheraz ahmad 张向群成昭华 State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences Department of Physics Beihang University

Buffer layer provides an opportunity to enhance the quality of ultrathin magnetic films. In this paper, Co films with different thickness of Co Si2 buffer layers were grown on Si（001） substrates. In order to investigate morphology, structure,and magnetic properties of films, scanning tunneling microscope（STM）, low energy electron diffraction（LEED）, high resolution transmission electron microscopy（HRTEM）, and surface magneto-optical Kerr effect（SMOKE） were used. The results show that the crystal quality and magnetic anisotropies of the Co films are strongly affected by the thickness of Co Si2 buffer layers. Few Co Si2 monolayers can prevent the interdiffusion of Si substrate and Co film and enhance the Co film quality. Furthermore, the in-plane magnetic anisotropy of Co film with optimal buffer layer shows four-fold symmetry and exhibits the two-jumps of magnetization reversal process, which is the typical phenomenon in cubic（001） films.

关键词： magnetic anisotropy Co Si2 buffer layers four-fold symmetry

Electron acoustic solitary waves in unmagnetized nonthermal plasmas

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Communications in Theoretical Physics 2021年第5期73卷 80-84页

作者： Muhammad Khalid Aqil Khan Mohsin Khan Daud Khan sheraz ahmad Ata-ur-Rahman Department of Physics Government Post Graduate College MardanMardan 23200Pakistan Theoretical Plasma Physics Group Department of PhysicsIslamia College Peshawar(Public Sector University)Peshawar 25120Pakistan Department of Physics Government Post Graduate College NowsheraNowshera 24100Pakistan

Electron acoustic(EA)solitary waves(SWs)are studied in an unmagnetized plasma consisting of hot electrons(following Cairns-Tsalli distribution),inertial cold electrons,and stationary *** employing a reductive perturbation technique(RPT),the nonlinear Korteweg–de Vries(KdV)equation is derived and its SW solution is ***,the effects of plasma parameters such as the nonextensivity parameter(q),the nonthermality of electrons(α),and the cold-to-hot electron density ratio(β)are investigated.

关键词： Electron acoustic solitons KdV equation Cairns-Tsalli distribution

Tunable in-plane spin orientation in Fe/Si(557) film by step-induced competing magnetic anisotropies

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Chinese Physics B 2016年第12期25卷 435-440页

作者：汤进何为张永圣李岩张伟 Syed sheraz ahmad 张向群成昭华 State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences School of Physical Sciences University of Chinese Academy of Sciences

the spin-reorientation transition from out-of-plane to in-plane in Fe/Si film is widely reported, the tuning of in-plane spin orientation is not yet well developed. Here, we report the thickness-, temperature- and Cu-adsorptioninduced in-plane spin-reorientation transition processes in Fe/Si （557） film, which can be attributed to the coexistence of two competing step-induced uniaxial magnetic anisotropies, i.e., surface magnetic anisotropy with magnetization easy axis perpendicular to the step and volume magnetic anisotropy with magnetization easy axis parallel to the step. For Fe film thickness smaller than 32 monolayer （ML）, the magnitudes of two effects under various temperatures are extracted from the thickness dependence of uniaxial magnetic anisotropy. For Fe film thickness larger than 32 ML, the deviation of experimental results from fitting results is understood by the strain-relief-induced reduction of volume magnetic anisotropy. Additionally, the surface and volume magnetic anisotropies are both greatly reduced after covering Cu capping layer on Fe/Si （557） film while no significant influence of NaC1 capping layer on step-induced magnetic anisotropies is observed. The experimental results reported here provide various practical methods for manipulating in-plane spin orientation of Fe/Si films and improve the understanding of step-induced magnetic anisotropies.

关键词： Fe/Si (557) films spin-reorientation transition competing magnetic anisotropies

Temperature dependence of multi-jump magnetic switching process in epitaxial Fe/MgO(001) films

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Chinese Physics B 2015年第7期24卷 34-39页

作者：胡泊何为叶军汤进张永圣 Syed sheraz ahmad 张向群成昭华 State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences

Temperature dependence of magnetic switching processes with multiple jumps in Fe/MgO（001） films is investigated by magnetoresistance measurements. When the temperature decreases from 300K to 80K, the measured three-jump hysteresis loops turn into two-jump loops. The temperature dependence of the fourfold in-plane magnetic anisotropy constant K1, domain wall pinning energy, and an additional uniaxial magnetic anisotropy constant KUare responsible for this transformation. The strengths of K1 and domain wall pinning energy increase with decreasing temperature, but KU remains unchanged. Moreover, magnetization reversal mechanisms, with either two successive or two separate 90°domain wall propagation, are introduced to explain the multi-jump magnetic switching process in epitaxial Fe/MgO（001） films at different temperatures.

关键词： multi-jump magnetic switching process magnetoresistance domain wall

Manipulating magnetic anisotropies of Co/MgO(001) ultrathin films via oblique deposition

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Chinese Physics B 2016年第9期25卷 551-555页

作者： Syed sheraz ahmad 何为汤进张永圣胡泊叶军 Qeemat Gul 张向群成昭华 State Key Laboratory of Magnetism and Beijing National Laboratory for Condensed Matter Physics Institute of PhysicsChinese Academy of Sciences

We present a systematic investigation of magnetic anisotropy induced by oblique deposition of Co thin films on MgO（001） substrates by molecular beam epitaxy at different deposition angles,i.e.,0？,30？,45？,60？,and 75？with respect to the surface *** energy electron diffraction（LEED）,surface magneto–optical Kerr effect（SMOKE）,and anisotropic magnetoresistance（AMR） setups were employed to investigate the magnetic properties of cobalt *** values of in-plane uniaxial magnetic anisotropy（UMA） constant Ku and four-fold magnetocrystalline anisotropy constant K1 were derived from magnetic torque curves on the base of AMR *** was found that the value of Ku increases with increasing deposition angle with respect to the surface normal,while the value of K_1 remains almost constant for all the ***,by using MOKE results,the Ku values of the films deposited obliquely were also derived from the magnetization curves along hard *** results of AMR method were then compared with that of hard axis fitting method（coherent rotation） and found that both methods have almost identical values of UMA constant for each sample.

关键词： magnetic anisotropy oblique deposition cobalt ultrathin film anisotropic magnetoresistance

Exciton-polariton based WS_(2)polarization modulator controlled by optical Stark beam

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Opto-Electronic Advances 2022年第11期5卷 54-60页

作者： Mahnoor Shahzadi Chuyuan Zheng sheraz ahmad Shanshan Wang Weili Zhang School of Information and Communication Engineering University of Electronic Science and Technology of ChinaChengdu 611731China College of Petroleum Engineering China University of PetroleumBeijing 102249China

The recent era of fast optical manipulation and optical devices owe a lot to exciton-polaritons being lighter in mass,faster in speed and stronger in nonlinearity due to hybrid light-matter *** room temperature existence of polaritons in two dimensional materials opens up new avenues to the design and analysis of all optical devices and has gained the researchers ***,spin-selective optical Stark effect is introduced to form a waveguide effect in uniform community of polaritons,and is used to realize polarization modulation of *** proposed device basically takes advantage of the spin-sensitive properties of optical Stark effect of polaritons inside the WS_(2)microcavity so as to guide different modes and modulate polarization of *** is shown that polaritonic wavepacket of different mode profiles can be generated by changing intensity of the optical Stark beam and the polarization of polaritons can be controlled and changed periodically along the formed waveguide by introduction birefringence that is sensitive to polarization degree of the optical Stark beam.

关键词： Stark beam polaritons modulator TMDs polarization degree

基于人工神经网络的太阳能智能直流住宅需求响应管理优化

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基于人工神经网络的太阳能智能直流住宅需求响应管理优化

作者： sheraz ahmad 华北电力大学(北京)

学位级别：硕士

对经济、绿色和最重要的可持续电力供应的追求推动了可再生能源（RES）在世界现有电力系统中的使用。进入新时代,为了实现可再生能源的最大效益,研究人员对电力系统中可再生能源的优化利用进行了大量研究。当前的知识体系记录了大量关... 详细信息

对经济、绿色和最重要的可持续电力供应的追求推动了可再生能源（RES）在世界现有电力系统中的使用。进入新时代,为了实现可再生能源的最大效益,研究人员对电力系统中可再生能源的优化利用进行了大量研究。当前的知识体系记录了大量关于需求响应（DR）优化技术的研究成果。到目前为止,近期研究工作的主要焦点是在不同的优化算法中使用传统的定价方案。但这项拟议的研究工作将旨在代表基于实时定价（RTP）的需求响应。该方案的实施将考虑现代地区配备最先进负载的国内电力系统。在MATLAB中开发了一个纳米网格（NG）来测试计划的优化方案。仿真模型包括一个为智能直流家庭供电的并网太阳能光伏系统。房屋荷载按其用途分为柔性荷载和非柔性荷载。人工神经网络（ANN）用于规划灵活负载并增加利润。仿真结果验证了所提出的动态定价方案的有效性,该方案比传统的静态定价方案具有更多的利润。纳米电网技术的迅速崛起为电力客户和电力供应商提供了更好的信息流、控制和灵活性。在这些优势中,纳米电网中消费者和发电者之间的相互信息流开辟了新的应用前景。智能家电与人工神经网络ANN连接,以协调受控家庭的电力需求。因此,从优化能源管理、可再生清洁能源和现代家电的角度来看,我们看到人们对智能家居越来越感兴趣。因此,本文研究了具有不同能源（如国家电网和光伏发电、纳米电网）的智能家电程序在时间序列中的优化调度。本文使用的可再生能源是作为发电设备的光伏板。根据负荷需求曲线中给出的不间断顺序阶段对设备运行进行建模。目标是最小化电力成本,同时满足持续时间、用户偏好和能源需求的限制。提出了一种优化算法,可以使家电使用的调度计划可用,例如神经网络技术。在家庭中增加光伏系统的效果是减少电费和家庭高峰需求。该条件通过使用MATLAB开发的最先进的建模方法进行了演示,旨在与需求侧管理的实时方法等效地获得DC家庭中家电的调度时间。

关键词：需求响应(DR) 纳米电网(NG) 人工神经网络(ANN) 实时定价(RTP) 可再生能源(RES) 智能直流家庭

Emerging insights into the function of very long chain fatty acids at cerebellar synapses

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Neural Regeneration Research 2025年第6期20卷 1709-1710页

作者： Martin-Paul Agbaga Mohiuddin ahmad Department of Cell Biology and Ophthalmology University of Oklahoma Health Sciences Centerand Dean McGee Eye InstituteOklahoma CityOKUSA

Very long chain-saturated and-polyunsaturated fatty acids(VLC-SFA and VLC-PUFA, respectively) are a functionally important class of fatty acids containing 28 carbons or more in their acyl chain. They are synthesized by the elongation of very long fatty acids-4(ELOVL4) enzyme, expressed mainly in the brain, retina, skin, testes, and meibomian gland, where these fatty acids are found(Agbaga et al., 2008). Further, these organs exhibit tissuespecific VLC-PUFA and VLC-SFA biosynthesis and incorporation into complex lipids for specific functions. In the brain, skin, and Meibomian glands, the ELOVL4 mainly makes VLC-SFA, which are incorporated into complex sphingolipids. In the retina, the ELOVL4 makes VLC-PUFA that are incorporated into phosphatidylcholine, that are critical for visual function, while in testes and sperm, the VLC-PUFA are incorporated into sphingolipids that are critical for fertility(Yeboah et al., 2021).

关键词： functions function insight

Secure Channel Estimation Using Norm Estimation Model for 5G Next Generation Wireless Networks

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Computers, Materials & Continua 2025年第1期82卷 1151-1169页

作者： Khalil Ullah Song Jian Muhammad Naeem Ul Hassan Suliman Khan Mohammad Babar Arshad ahmad Shafiq ahmad Faculty of Information Engineering and Automation Kunming University of Science and TechnologyKunming650500China Department of Computer Science Abbottabad University of Science and TechnologyHavelianAbbottabad22500Pakistan Department of Computing and Electronics Engineering Middle East CollegeMuscat124Oman Department of CS&IT Pak-Austria Fachhochschule Institute of Applied Sciences and Technology MangHaripur22621Pakistan Industrial Engineering Department College of EngineeringKing Saud UniversityRiyadh11421Saudi Arabia

The emergence of next generation networks(NextG),including 5G and beyond,is reshaping the technological landscape of cellular and mobile *** networks are sufficiently scaled to interconnect billions of users and *** in academia and industry are focusing on technological advancements to achieve highspeed transmission,cell planning,and latency reduction to facilitate emerging applications such as virtual reality,the metaverse,smart cities,smart health,and autonomous *** continuously improves its network functionality to support these *** input multiple output(MIMO)technology offers spectral efficiency,dependability,and overall performance in *** article proposes a secure channel estimation technique in MIMO topology using a norm-estimation model to provide comprehensive insights into protecting NextG network components against adversarial *** technique aims to create long-lasting and secure NextG networks using this extended *** viability of MIMO applications and modern AI-driven methodologies to combat cybersecurity threats are explored in this ***,the proposed model demonstrates high performance in terms of reliability and accuracy,with a 20%reduction in the MalOut-RealOut-Diff metric compared to existing state-of-the-art techniques.

关键词： Next generation networks massive mimo communication network artificial intelligence 5G adversarial attacks channel estimation information security