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The Effect of High Power at Microwave Frequencies on the Linearity of Non-Polar Dielectrics in Space RF component

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International Journal of Communications, Network and System Sciences 2015年第2期8卷 11-18页

作者： Tawfik elsayed Khattab Department of Electrical Engineering Engineering College King Khalid University Abha Saudi Arabia

In satellite communication systems, there are high power multichannel transmitters and wideband receivers that have shared RF antenna transmission lines because of: 1) large power level difference between the transmitted and received signal;2) limited frequency channels. The harmonics and Passive Intermodulation (PIM) Interference will be generated due to passive non-linearities in the high power transmission path. This can be a serious problem. This paper describes how to determine the signal levels and dominant mechanisms that are associated with non-linear dielectric behavior in this context. A novel measurement system for testing dielectric samples is described and measurement results are provided for commonly used microwave dielectrics.

关键词： Passive Intermodulation PIM Nonlinear Polar Dielectric Harmonics Cavity Resonator

Comparing the Efficacy of Dexmedetomidine When Used as an Adjuvant to Bupivacaine in Supraclavicular Brachial Plexus Blocks under Ultrasound-Guided

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Open Journal of Anesthesiology 2019年第5期9卷 99-109页

作者： elsayed Mohamed abdelzaam Faculty of Medicine Benha University Banha Egypt

Background: Ultrasound-guided for regional anesthesia offers many potential benefits in the emergency setting. Analgesia can be explicitly targeted to the region of pain and provide relief for many hours and decrease needing to the large volume of local anesthetic. The aim of the work: Comparing the efficacy of dexmedetomidine when used as an adjuvant to bupivacaine in supraclavicular brachial plexus blocks on the onset of sensory, motor blockade and postoperative analgesia. Patients and methods: This prospective, randomized, single-blind clinical study conducted on 60 patients underwent upper limb surgery done by ultrasound-guided supraclavicular brachial plexus block;these patients allocated into two equal groups: Group I (control) received 20 ccs (19 cc bupivacaine 0.5% + 1 cc saline), Group II received 20 cc (19 cc bupivacaine 0.5% + 1 cc volume of Dexmedetomidine 1 ug/kg). Results: Demographic data and surgical characteristics were comparable in both groups. The onset times for sensory and motor blocks were significantly shorter in Group II than Group I (P Conclusion: We recommend adding Dexmedetomidine to local anesthetics in peripheral nerve blocks to take advantage of the prolonged time of both sensory and motor blocks and prolonged postoperative analgesia.

关键词： Dexmedetomidine Bupivacaine Supraclavicular Brachial Plexus Blocks Ultrasound-Guided

Enhancing the explosive characteristics of a Semtex explosive by involving admixtures of BCHMX and HMX

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Defence Technology（防务技术） 2020年第2期16卷 487-492页

作者： Ahmed Elbeih Ahmed K.Hussein Tamer Elshenawy Svatopluk Zeman Sara M.Hammad Ahmad Baraka Mohamed A.elsayed Mohamed Gobara Hesham Tantawy Military Technical College Kobry ElkobbahCairoEgypt Technical Research Center CairoEgypt Institute of Energetic Materials Faculty of Chemical TechnologyUniversity of PardubiceCzech Republic Faculty of Pharmacy University of CairoGizaEgypt

A well-known ternary plastic explosive,Czech Semtex 1H,contains a mixture of PETN and RDX softened by *** this work,BCHMX was used to replace PETN in Semtex 1H to form Sem-BC+*** addition,another mixture based on BCHMX and HMX as energetic fillers bonded by the polymeric matrix of Semtex 1H(Sem-BC+HMX)was *** particle size distribution of each individual explosive was determined to obtain the optimum mixing *** and impact sensitivities were *** velocity of detonation was reported practically and the detonation properties were calculated by EXPLO5 *** explosive strength of each sample was measured by the ballistic mortar *** conclusion confirms that the velocity of detonation of Sem-BC+HMX was the highest in comparison with the prepared ***-BC+RDX has the least impact and frictions ***-BC+RDX has higher detonation velocity,detonation properties and explosive strength than Semtex *** of BCHMX in Semtex 1H as a replacement for PETN is the candidate to produce a high performance advanced Czech plastic explosive.

关键词： Semtex Explosives Combustion Sensitivity Detonation Explosive strength

Enhancing the Accuracy for Target Detection by Using Fast Orthogonal Search (FOS)

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Computer Aided Drafting,Design and Manufacturing 2010年第1期20卷 93-98页

作者： ESSAM A. elsayed School of Electronic and Information Engineering Beijing University of Aeronautics and Astronautics

Target detection and bearing estimation are mainly obtained through spectral analysis of received signals. The detection performance of the periodogram and its variants methods is evaluated. The variants methods Performance evaluation through the Receiver Operating Characteristics （ROCs） are presented and compared from the viewpoint of probability of detection （Pd）, probability of false alarm （Pfa） by computer simulation. When the sinusoid frequency does not correspond to one of the spectral bins （mid-bin frequency situation）, the performance of all the mentioned detectors degrades. This research investigates the development of a bearing estimation method using Fast Orthogonal Search （FOS） to enhance spectral estimation which, improves both target detection and bearing estimation in case of low SNR inputs.

关键词： fast orthogonal search peridogram probability of detection power spectrum

Graduate Students and Companies Web Based E-Recruitment System

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Journal of Computer and Communications 2021年第9期9卷 71-84页

作者： Zohair Malki elsayed Atlam College of Computer Science and Engineering Taibah University Yanbu KSA Faculty of Science Tanta University Tanta Egypt

Computer systems help to improve human life in all sectors. One of the most important sectors that the recent systems support is the recruitment sector. Recruiters used to waste their valuable time, effort and money to reach the best candidates. The traditional recruitment process fulfills neither the recruiter needs nor the job seeker ambitions. Nowadays, companies use their website or social media to announce job vacancy whereas job seekers usually use job portal to market their abilities and skills. All these can be put on one recruitment website to improve the process for both parties. The proposed system will build an online E-recruitment system for recruiters (companies) and job seekers that will help them to interact with each other and to match their expectations. This system will be developed using Hyper Text pre-processor (PHP), Hyper Text Markup Language (HTML), Cascading Style Sheet (CSS), JQ, MySQL, and XMMAP. Moreover, the recent human computer interaction (HCI) concepts will apply to provide good user experience through simple, clear, and modern interfaces. Our E-recruitment system is directed to all graduated students from university in all programs. The system allows the recruiters (companies) to post announcement for job vacancy and to search for job seeker or about another company, and to view the applied job. For the job seeker it allows graduate student to search for job, apply for the available opportunities, upload CV, and setup his own profile. Finally, this study will help to improve the experience and break the difficulties that present in the recruitment process as well as support the human resource (HR) department in companies and other sectors. Finally, the results show the average score of 4.72 out of 5, indicating that the users are feeling enjoyable while using the application features and the system is easy to use.

关键词： PHP HR E-Recruitment System HCI Graduate Student Companies

Serum Vitamin B12 and Homocysteine Levels in Type 2 Diabetic Patients with and without Metformin Therapy

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Journal of Biomedical Science and Engineering 2019年第12期12卷 557-570页

作者： Fathy elsayed abdelgawad Medical Biochemistry Department Faculty of Medicine Al-Azhar University Cairo Egypt Medical Laboratory Department University Medical Center Islamic University of Madinah Madinah KSA Female Section University Medical Center Islamic University of Madinah Madinah KSA

Background: Vitamin B12 (cobalamin) is an essential micronutrient necessary for DNA methylation and plays role in lipid metabolic reactions. Metformin is the first therapeutic choice for T2DM management. Prolonged use of metformin causes vitamin B12 deficiency due to poor absorption by interfering with calcium-based vitamin B12 absorption. Vitamin B12 deficiency leads to elevated homocysteine levels. The aim of this study was to evaluate serum vitamin B12 and homocysteine levels in type 2 diabetic patients with and without metformin therapy. Methods: A cross-sectional study was conducted on two hundred and thirty diabetic patients (180 males and 50 females). Their ages ranged from (30 - 60 years) living in Saudia Arabia at Al-Madinah Al-Monawarah. Patients were selected at outpatients clinics of Islamic University Medical Center during follow up at internal medicine and endocrinology clinic. The included patients were diagnosed with type 2 diabetes mellitus according to American Diabetes Association (ADA) Criteria. The included patients were categorized into two groups according to treatment with metformin drug. Laboratory measurements included serum level of vitamin B12, serum total homocysteine, serum fasting glucose and serum folate. Blood EDTA samples were used to measure HbA1c and MCV. Neurological examinations were performed to detect presence of peripheral neuropathy using Toronto Clinical Neuropathy Score (TCSS), which is a validated and reliable scale for the diagnosis and staging of diabetic polyneuropathy. Results: There were no statistical differences between the two groups as regard (age, sex, smoking, weight, BMI, systolic blood pressure, diastolic blood pressure, fasting blood glucose, Folate and MCV). There were statistical differences between the two groups as regard (duration of diabetes, duration of metformin therapy, dose of metformin, Serum homocystein and HbA1c). The mean of vitamin B12 (pg/mL) of group 1 (312.65 ± 92.28) was lower than that of

关键词： Diabetes Metformin Vitamin B12 Homocysteine Peripheral Neuropathy

Generalized Thermo Elasticity in an Infinite Nonhomogeneous Solid Having a Spherical Cavity Using DPL Model

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Applied Mathematics 2011年第5期2卷 625-632页

作者： Ahmed elsayed Abouelrega 不详

The induced temperature, displacement, and stress fields in an infinite nonhomogeneous elastic medium having a spherical cavity are obtained in the context dual-phase-lag model. The surface of the cavity is stress free and is subjected to a thermal shock. The material is elastic and has an in?homogeneity in the radial direction. The type of non homogeneity is such that the elastic constants, thermal conductivity and density are propor?tional to the nth power of the radial distance. The solutions are obtained analytically employing the Laplace transform technique. The numerical inversion of the transforms is carried out using Fourier series expansions. The stresses, temperature and displacement are computed and presented graphically. A comparison of the results for different theories is presented.

关键词： Generalized Thermo Elasticity Nonhomogeneous Functionally Graded Material (FGM) Laplace Transform Three-Phase-Lag Model

Corneal sensitivity,ocular surface health and tear film stability after punctal plug therapy of aqueous deficient dry eye

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International Journal of Ophthalmology(English edition) 2016年第11期9卷 1598-1607页

作者： Azza Mohamed Ahmed Said Mona elsayed Farag Tarek Mohamed abdulla Othman Ali Othman Ziko Wesam Mohamed Osman Ophthalmology Department Faculty of MedicineAin Shams University Pathology Department Faculty of MedicineAin Shams University

AIM： To evaluate the effect of punctal occlusion using thermosensitive（smart plug） versus silicone plug for management of aqueous deficient dry eye on cornea sensitivity, ocular surface health and tear film ***： A comparative prospective interventiona case study included 45 patients with bilateral severe form of aqueous deficient dry eye. In each patient, the smar plug was inserted in the lower punctum of the right eye which was considered as study group 1 and silicone plug was inserted in the lower punctum of the left eye o the same patient which was considered as study group2. All patients were subjected to careful history taking and questionnaire for subjective assessment of severity of symptoms. Corneal sensitivity, corneal fluorescein rose bengal staining, Schirmer＇s I test, tear film break up time and conjunctival impression cytology were performed pre and 1, 3 and 6mo post plug ***： A statistically significant improvement in subjective and objective manifestations occurred following treatment with both types of plugs（P 〈0.01）The thermosensitive plug caused significant overal improvement, decrease in frequency of application o tear substitutes and improvement of conjunctiva impression cytology parameters in the inserted side（P 〈0.01）. Canaliculitis was reported in two eyes（4.4% following punctal occlusion using thermosensitive plug（study group 1）. Spontaneous plug loss occurred in 21eyes（46.6%） in the silicone plug group（study group 2）.CONCLUSION： Improvement of subjective and objective manifestations of aqueous deficient dry eye occurs following punctal plug occlusion. Thermosensitive plug has good patient＇s compliance with fewer complications and lower rates of loss compared to the silicone plug.

关键词： conjunctival impression cytology comealsensitivity corneal fluorescein staining dry eye syndrome Schirmer's test silicone plug thermosensitive smart plug

生物炭和滴灌量对陕北榆林沙土性质和马铃薯生长的影响

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中国农业科技导报 2023年第3期25卷 221-233页

作者：杨玲张富仓孙鑫张少辉王海东 abdELGHANY Ahmed elsayed 陈占飞方玉川西北农林科技大学旱区农业水土工程教育部重点实验室陕西杨凌712100 陕西省榆林市农业科学院陕西榆林719000

生物炭具有改良土壤和节水保肥增产的效应,针对榆林沙土地持水保肥能力低的问题,将滴灌施肥与生物炭相结合,探究生物炭施用量和滴灌量对土壤理化性质和马铃薯生长的影响。大田试验设置2个滴灌量水平80%ET_(c)(W1)和100%ET_(c)(W2),5个... 详细信息

生物炭具有改良土壤和节水保肥增产的效应,针对榆林沙土地持水保肥能力低的问题,将滴灌施肥与生物炭相结合,探究生物炭施用量和滴灌量对土壤理化性质和马铃薯生长的影响。大田试验设置2个滴灌量水平80%ET_(c)(W1)和100%ET_(c)(W2),5个生物炭水平0(B0)、10(B10)、20(B20)、30(B30)和50 t·hm^(-2)(B50),共10个处理,生育期内对土壤容重、孔隙度、有机碳、土壤水分、速效钾、硝态氮、干物质累积量及产量等进行观测。结果表明,随着生物炭施用量的增加,0—20 cm土层土壤容重显著降低,土壤孔隙度、土壤有机碳含量和土壤速效钾含量显著增加,土壤硝态氮含量和含水量先增加后减小。随着滴灌量增加,0—20 cm土层土壤容重降低,土壤孔隙度和含水量增大。生物炭的施用仅对生长后期马铃薯干物质累积量促进效果显著,表现为随着生物炭施用量的增加先增加后减少。马铃薯块茎产量和水分利用效率随着施炭量的增加先增加后减小,马铃薯块茎产量随着滴灌量的增大而增大,W2B30处理下最高,为58263.89 kg·hm^(-2),但与W1B20、W1B30、W2B20处理无显著差异,而水分利用效率最大值出现在W1B20处理,所以从产量、水分利用效率以及经济的角度考虑,W1B20可作为本试验条件下较适宜的水炭组合。

关键词：马铃薯生物炭滴灌量土壤性质生长产量