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Simulated and experimental studies of a multi-band symmetric metamaterial absorber with polarization independence for radar applications

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Chinese Physics B 2022年第5期31卷 703-710页

作者： Hema O.Ali Asaad M.Al-Hindawi yadgar i.abdulkarim Ekasit Nugoolcharoenlap Tossapol Tippo FatihÖzkan Alkurt Olcay Altintas Muharrem Karaaslan Department of Communication Engineering Sulaimani Polytechnic UniversitySulaimani 46001Iraq Medical Physics Department College of Medicals and Applied ScienceCharmo UniversityChamchamal 46023SulaimaniaIraq Department of Telecommunication Engineering Faculty of EngineeringRajamangala University of Technology RattanakosinPhutthamonthonNakornprathom 73170Thailand Department of Electrical and Electronics Engineering Iskenderun Technical UniversityHatay 31100Turkey

We develop a simple new design for a multi-band metamaterial absorber(MTMA)for radar *** Simulation Technology(CST)Studio Suite 2018 was used for the numerical analysis and absorption *** simulated results show four high peaks at 5.6 GHz,7.6 GHz,10.98 GHz,and 11.29 GHz corresponding to absorption characteristics of 100%,100%,99%,and 99%,***,two different structures were designed and compared with the proposed *** proposed structure remained insensitive for any incident angle and polarization angle from 0°to60°.Moreover,negative constitutive parameters were retrieved *** support the simulated results,the proposed design was fabricated by using a computer numerical control-based printed circuit board prototyping machine and tested experimentally in a microwave *** absorption mechanism of the proposed MTMA is presented through the surface current and electric field *** novelties of the proposed structure are a simple and new design,ease of fabrication,low cost,durability,suitability for real-time applications and long-term stability given the fabrication technique and non-destructive measurement method and very high *** proposed structure has potential applications in C and X band frequency ranges.

关键词： multi-band metamaterials absorber polarization-independent negative parameters

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Tunable left-hand characteristics in multi-nested square-split-ring enabled metamaterials

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Journal of Central South University 2020年第4期27卷 1235-1246页

作者： abdulkarim yadgar.i DENG Lian-wen YANG Jun-liang COLAK Sule KARAASLAN Muharrem HUANG Sheng-xiang HE Long-hui LUO Heng School of Physics and Electronics Central South UniversityChangsha 410083China Physics Department College of ScienceUniversity of SulaimaniSulaymaniyah 46001Iraq Department of Electrical and Electronics Engineering Adana Alparslan Turkes UniversityAdana 01140Turkey Department of Electrical and Electronics Engineering Iskenderun Technical UniversityHatay 31200Turkey

Left-hand materials have drawn increasing attention from many disciplines and found widespread application, especially in microwave engineering. A sandwiched metamaterial consisting of multi-nested square-split-ring resonators on the top side and a set of wires on the back side is proposed. Scattering parameters are retrieved by high-frequency structure simulator(HFSS) software based on the finite element method. Effects of square-split-ring number on the left-hand characteristics containing negative values of permittivity, permeability, and refractive index have been intensively investigated. Simulated results show that obvious resonant left-hand characteristics could be observed within 8-18 GHz, and the resonant frequency counts are inclined to be in direct proportion to the square-split-ring number over 8-18 GHz. Besides, the proposed sandwiched metamaterial with three square-split-ring resonators and three wires presents the widest frequency band of left-hand characteristics in a range of 8-18 GHz. Further, electromagnetic field distributions demonstrated that the induced magnetic dipole dominates the resonant absorption. The multi-peak resonance characteristics of square-split-ring resonant structure are considered to be a promising candidate for selective-frequency absorption or modulation toward microwave frequency band.

关键词： metamaterial square-split-ring negative permittivity induced magnetic dipole

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The effect of individual factors on user behaviour and the moderating role of trust: an empirical investigation of consumers’ acceptance of electronic banking in the Kurdistan Region of iraq

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Financial innovation 2020年第1期6卷 703-731页

作者： yadgar Taha M.Hamakhan Doctoral School of Management and Organizational Science Szent István University Kaposvár CampusGuba Sándor u.40Kaposvár 7400Hungary Economics Department College of Administration and EconomicsUniversity of SulaimaniSulaymaniyahKurdistan RegionIraq

The popularity of self-service technologies,particularly in the banking industry,more precisely with electronic banking channel services,has undergone a major change as individuals’lifestyles *** change has affected individuals’decisions about accepting any new information Technology,and information Communications Technology services that are electronically mediated,for example,E-Banking channel *** study investigates the effect of individual Factors on User Behaviour,and the moderating role of Trust in the relationship between individual Factors,and User Behaviour based on the Unified Theory of Acceptance and Use of *** research proposes a model,with a second-order components research *** improves current explanations of the acceptance of electronic banking channel ***,this study highlights the role of trust on the acceptance of electronic banking channel services,which is the most crucial consideration in customers’decisions to accept electronic banking channels ***,trust is the spine of the system in the Kurdistan Region of *** were collected using an online questionnaire that received 476 valid responses from academic staff who work at the University of *** model tested data using the Partial Least Squares-Structural Equation Modelling *** results show that individual Factors have a positive effect on User ***,results show that trust moderates the relationship between individual Factors and User Behaviour.

关键词： Cash society Offline banking Technology acceptance model Decision makers PLSpredict

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HER2表达在早期胃癌预后中的意义:一项系统综述和荟萃分析

HER2表达在早期胃癌预后中的意义:一项系统综述和荟萃分析

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作者： yadgar Hasibullah 中国医科大学

学位级别：硕士

研究背景与目的:早期胃癌（Early gastric cancer,EGC）是指病灶仅局限于粘膜或粘膜下层的胃癌,而不论是否有局部淋巴结转移。近年来随着消化道内镜技术的发展与普及,早期胃癌的检出率也在逐年提升。我国每年新发胃癌病例中,早期胃癌约... 详细信息

研究背景与目的:早期胃癌（Early gastric cancer,EGC）是指病灶仅局限于粘膜或粘膜下层的胃癌,而不论是否有局部淋巴结转移。近年来随着消化道内镜技术的发展与普及,早期胃癌的检出率也在逐年提升。我国每年新发胃癌病例中,早期胃癌约占20%。而在日韩等国家,超过一半的新发胃癌,是早期胃癌。目前,早期胃癌的治疗方法,除了常规的手术切除之外,还包括内镜治疗（包括黏膜切除术,endoscopic mucosal dissection,EMR,和黏膜下剥离术,endoscopic submucosal dissection,ESD）。内镜下治疗后获得的标本有限,无法像手术切除那样获得较为完整的胃组织,因此在术后病理学诊断与评估方面,缺少了很多重要的信息。比如局部淋巴结转移情况等。因此,与进展期胃癌不同,早期胃癌的预后相关风险评估,有其自身的特殊性。对于进展期胃癌,在接受手术切除后,其预后相关风险因素主要为术后的病理信息,如肿瘤浸润深度、病变大小、细胞分化程度、淋巴结转移情况等。在这些因素中,淋巴结转移被认为是早期胃癌术后预后不佳的独立危险因素。但由于早期胃癌的淋巴结转移率较低,仅为8～15%。尤其是经内镜下治疗后的早期胃癌病例,术后病理检查无法评估淋巴结转移的情况。因此,对于大部分早期胃癌患者,无法应用淋巴结转移情况来评估预后。而病灶大小、细胞分化程度、淋巴血管侵袭、神经浸润情况等,是否与早期胃癌预后相关,仍存在争议。因此,找到更加符合早期胃癌特点的预后相关因素,对于更加全面、合理的评估早期胃癌的复发风险,具有重要的临床意义。近年来,随着分子生物学检测技术在临床上的普遍应用,HER2蛋白、微卫星不稳定等肿瘤相关的生物标志物,在进展期胃癌患者的分子分型、治疗方案选择、预后评估等方面,发挥了重要的作用。但在早期胃癌的应用中,还存在着争议。这些生物标志物代表了肿瘤细胞的内在特征,并不受治疗方式的影响。因此,对于淋巴结转移率低且术后无法获得足够病理信息的早期胃癌患者,具有独特的临床应用价值。人表皮生长因子受体2（Human Epidermal Growth Factor Receptor 2,HER2）又叫做ERBB2,其编码基因位于染色体17q12区域内。HER2蛋白是EGFR家族中的一员,这个家族包括四个成员,分别为HER1,HER2,HER3,HER4,它们都是具有酪氨酸激酶活性的跨膜蛋白。HER2蛋白必须与家族其他成员组成同源或异源二聚体,HER2二聚化后构象发生改变,激活胞内的酪氨酸激酶活性,从而启动下游信号传导通路。HER2蛋白可通过激活Ras-Raf-MEK-MAPK通路与Pi3K-AKT通路,激活线粒体的活性,从而调节细胞增殖和抑制凋亡。此外,HER2蛋白也在Janus激酶/信号转导和转录激活因子通路以及磷脂酶C通路等其他通路中发挥着重要作用。因其重要的生物学功能,HER2基因在多种肿瘤中均存在异常过度表达的现象,如乳腺癌、结直肠癌、肺癌、卵巢癌等。在胃癌中,HER2异常过表达的比例约为7%～34%。从肿瘤进化的角度看,HER2基因作为重要的肿瘤驱动基因,其过度活化发生在细胞癌变的早期。有研究显示,在胃粘膜出现癌前病变时,就已经出现了HER2过表达的现象,但扩增率较低。随着细胞不断演进,HER2的表达也逐渐增高。HER2过表达的程度与肿瘤的进展也密切相关,这些均表明HER2过表达是贯穿胃癌整个发生发展过程的重要分子事件。多项研究表明,HER2过表达是进展期胃癌预后不良的风险因素之一。但是否与早期胃癌的预后相关,还存在着争议。造成早期胃癌各研究的结果不一致的原因可能有以下几个方面:1,标本获取的方式不一致。内镜下切除与手术切除获得的标本,在离体时间、固定方式、染色流程等方面均有较大的不同。这对于HER2表达的检测结果可能存在着潜在的影响。2,HER2检测方法不一致。目前,NCCN指南中建议应用免疫组化（immunohistochemistry,iHC）与原位杂交（in situ hybridization,iSH）联合检测的方法,已成为共识。但在数年前发表的研究中,只应用了iHC法检测。3,患者的种族不一致。虽然目前尚无明确的证据显示,不同种族的胃癌患者在HER2等分子标志物上存在着差异。但东西方胃癌患者,在肿瘤特点、发病部位、治疗模式等方面确实存在着不同,这也得到了多数学者的认可。也有研究报道了部分早期胃癌患者在接受了根治性手术治疗后,术后病理显示该患者并无淋巴结转移,但该患者在术后也出现了异时性肝转移与骨转移。同时免疫组化结果显示该患者的肿瘤组织中存在HER2过表达现象,这说明除淋巴结转移之外,HER2过表达很有可能是影响早期胃癌患者预后的因素之一。因此,本研究拟对这一科学问题进行系统综述,并利用荟萃分析的方法,

关键词： HER2 早期胃癌预后系统综述

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