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DFT investigation of half-metallic ferromagnetic rare earth based spinels mgHo_(2)Z_(4)(Z=S,Se)

Journal of Rare Earths 2024年第1期42卷 121-128,I0005页

作者： maiza Zanib mumtaz manzoor N.A.Noor m.Waqas Iqbal mazia Asghar H.H.Hegazy A.Laref Department of Physics Riphah International UniversityLahore CampusPakistan Research Centre for Advanced materials Science King Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics Faculty of ScienceKing Khalid UniversityP.O.Box 9004AbhaSaudi Arabia Department of Physics and Astronomy College of ScienceKing Saud UniversityRiyadh11451Saudi Arabia

Half-metallic ferromagnetism,mechanical as well as thermoelectric properties for rare earth-based spinels mgHo_(2)Z_(4)(Z=S,Se)were investigated using density functional theory(DFT).Structural optimization was done with Perdew-Burke-Ehrenzorf(PBE)sol-generalized gradient approximation(GGA)to calculate the lattice constant of both spinels comparable to experimental *** addition,Born stability criteria and negative formation energy show that our studied spinels are also structurally and dynamically stable in the cubic *** ferromagnetic(Fm)state stability,we also calculated the energy differences among Fm,antiferromagnetic(AFm),and non-magnetic(Nm)***,Curie temperatures of ferromagnetic phases were also *** used Trans-Blaha improved BeckeJohnson(TB-mBJ)potential functional for electronics as well as magnetic characteristics,which lead to the consistent explanation of half-metallic ferromagnetism,representing the whole band-occupancy in material with exact detail of density of states(DOS).The stable Fm state was examined in spinels due to the exchange splitting of Ho cation consisting of p-d hybridizations compatible with the result achieved for electronics band structure and ***,spin magnetic moment was explained in terms of anion,cation,and sharing charge on studied *** addition,the calculated thermoelectric properties clearly show that operation range of these systems may be utilized by future experimental works for identifying the potential applications of these systems.

关键词： Ho-based spinels DFT simulations mechanical parameters electronic properties hm ferromagnetism Figure of merit

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Effect of Conductive Fillers on the Cyclic Stress-Strain and Nano-Scale Free Volume Properties of Silicone Rubber

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Chinese Journal of Polymer Science 2014年第5期32卷 558-567页

作者： m.H.Abd-el Salam S.el-Gamal m.mohsen D.m.Abd el-maqsoud Physics Department Faculty of Education Ain Shams University Physics Department Faculty of Science Ain Shams University

The effect of carbon black （CB） and graphite （G） powders on the macroscopic and nano-scale free volume properties of silicone rubber based on poly（di-methylsiloxane）（PDmS） was studied through thermal and cyclic mechanical measurements, as well as with positron annihilation lifetime spectroscopy （PALS）. The melting temperature of the composites （Tm） and the endothermic enthalpy of melting （Δhm） were estimated by differential scanning calorimetry （DSC）. Tm and the degree of crystallinity （χc） of PDmS composites were found to decrease with increasing the CB content. This can be explained due to the increase in physical cross-linking which results in a decrease in the crystallite thickness. Besides, χc was found to be dependent on the filler type. Cyclic stress-strain behavior of PDmS loaded with different contents of filler has been studied. mullins ratio （Rm） was found to be dependent on the filler type and content. It was found that, Rm increases with increasing the filler content due to the increase in physical cross-linking which results in a decrease in the size of free volume, as observed through a decrease of the o-Ps lifetime τ3 measured by PALS. moreover, the hysteresis in PDmS-CB composites was more pronounced than in PDmS-G composites. Furthermore, a correlation was established between the free volume Vf and the mechanical properties of PDmS composites containing different fillers. A negative correlation was observed between Vf and Rm.

关键词： Positron annihilation Positronium Free volume Si-rubber Composite Cyclic mechanical properties.

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Hematology and Some Biochemical Parameters of Wild Rodents in Pistachio Gardens of Kerman Province, Southeast Iran

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应用与环境生物学报 2011年第6期17卷 907-909页

作者： mADJDZADEH Sm ABBASNEJAD m TAKALLOOZADEH hm mammalian Biodiversity Research Unit Department of Biology Faculty of Sciences Shahid Bahonar University of Kerman 76169-14111 Kerman Iran Department of Plant Pathology Faculty of Agriculture Shahid Bahonar University of Kerman 76169-14111 Kerman Iran

Wild rodents were collected using live snap traps in pistachio gardens of Kerman Province, Southeast Iran from 2007 to 2009, then some physiological parameters of them were measured. The samples were identified as follow: Nesokia indica, meriones persicus, meriones lybicus and Tatera indica. Blood samples were obtained from the heart, then the blood parameters (glucose, cholesterol, triglyceride, total protein, HDL, red and white blood cell number) in wild species of rodents and laboratory rat were compared. The results showed that there were no significant differences in serum glucose, triglyceride, HDL and total protein levels among different experimental groups. The concentration of cholesterol in T. indica was more than that in N. indica (P mbers of red blood cells also showed significant difference between wild garden rodent species and laboratory rat (P mbers of white blood cells showed no significant difference.

关键词： rodents hematological parameter biochemical parameter pistachio gardens Kerman Province, Iran

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Dose-dependent effect of histamine on antibody generation in vivo

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Asian Pacific Journal of Tropical medicine 2010年第2期3卷 112-116页

作者： Tripathi T Shahid m Khan hm Khan RA Siddiqui mU DePartment of Biochemistry Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University Department of microbiology Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University Department of Pharmacology Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University Department of Biochemistry Faculty of MedicineJawaharlal Nehru Medical College and HospitalAligarh Muslim University

Objective:To delineate immunomodulatory role of histamine on antibody generation pr of ile in rabbit in the present dose-dependent histamine ***:The cohort comprised of three groups(Ⅲ,ⅣandⅤ),containing six rabbits each,and received subcutaneous histamine 50μg/kg×bis in die(b.i.d.),100μg/kg×*** 200μg/kg X b.i.d.,respectively for 10 days (starting from the 1st day).They were subsequently immunized on the 3rd day with intravenous injection of sheep blood cell(SRBC)(1×10 cells/mL).GroupⅡ(positive control)(n=6) received vehicle(sterile distilled water) and immunized at day 3 similarly while groupⅠ(negative control) (n=6) remained non-immunized and received only *** experimentations were performed in *** samples were collected on pre-immunization(pre-I)(day 0),as well as on days 7-,14-,21-,28- and 58- post-immunization(post-I).Immunological parameters[total immunoglobulins(Igs),Igm and IgG]were analyzed by enzyme linked immunosorbent assay (elISA) ***:Histamine could influence a detectable antibody response to SRBC as early as day 7-post-I,which lasted until day 58- *** results were found statistically significant(Pmine has a short-term effect on antibody generation(until its presence in the body),and the antibody generation titer in vivo were affected by the concentration of histamine.

关键词： Histamine Immumomodulation T-cell dependent antibody response Humoral immune response SRBC

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COX-2 polymorphisms-765G→C and-1195A→G and colorectal cancer risk

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World Journal of Gastroenterology 2009年第36期15卷 4561-4565页

作者： Juliёt H Hoff Rene hm te morsche Hennie mJ Roelofs elise mJ van der Logt Fokko m Nagengast Wilbert hm Peters Department of Gastroenterology Radboud University Nijmegen Medical Center6500 HB NijmegenThe Netherlands

AIm： TO determine the possible modulating effect of the COX-2 polymorphisms, -765G→C and -1195A→G, on the risk of colorectal cancer （CRC） in a Dutch population. mETHODS： This case-control study includes 326 patients with CRC and 369 age- and gender-matched controls. Genotypes of the COX-2 polymorphisms -7dEG→C and -1195A→G were determined by polymerase chain reaction-based restriction fragment length polymorphism. COX-2 genotypes and haplotypes were analyzed and odds ratios with 95% confidence intervals were estimated by logistic regression. RESULTS： The -765GG genotype was associated with an increased risk of developing CRC （OR, 1.45; 95% CI, 1.03-2.04）. No significant difference was observed in the genotype distribution of the -1195A→G polymorphism between patients and controls. The GG/AC haplotype was present significantly less often in patients than in controls （OR 0.44; 95% CI, 0.22-0.85）. When the AC, AG and GG haplotypes were investigated separately, the AC haplotype showed a tendency to be less frequent in patients than in controls （OR（AG/AC） 0.78; 95% CI, 0.57-1.06）. CONCLUSION： The -765GG genotype is associated with an increased risk of developing CRC and the G6/ AC haplotype seems to protect against CRC. These findings suggest a modulating role for the COX-2 polymorphisms -765G→C and -1195A→G in the development of CRC in a Dutch population.

关键词： Colorectal carcinoma Cyclooxygenase-2 Genetic polymorphism

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Evaluation of diameter dis-tribution of inside cavities of open CNTs by analyses of nitrogen cryo-adsorption isotherm

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Chinese Science Bulletin 2001年第15期46卷 1317-1320页

作者： Yang, QH Li, F Hou, PX Liu, C Liu, m Cheng, hm Chinese Acad Sci Inst Met Res Shenyang 110015 Peoples R China

Precise evaluation of innerdiameter distribution of open carbon nanotubes (CNTs) is the basis of systematic investigation of physico-chemical processes occurring in nano-sized quasi-1-dimensional carbons. Due to the porosity characteristics and adsorption properties, this study evaluated the innerdiameter and its distribution of carbon nanotubes by analyses of nitrogen cryo-adsorption isotherms, and proved that the gas adsorption method is an effective method to characterize the inner cavity structure in comparison with that of electron microscopy observations and Raman measurements. The advantages of this method are as follows: Firstly, statistical information for innerdiameter distribution of open nanotubes can be obtained; Secondly, the method based on the adsorption process in inner cavities is of importance for investigation of other physico-chemical pro- cesses inside the cavities of carbon nanotubes. And finally, if combining with other characterization methods, complete structural information

关键词： carbon nanotubes (CNTs) innerdiameter distribution gas adsorption method adsorption isotherm.

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Periodic surface structures fabricated by one excimer laser pulse through a silica phase mask grating

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Chinese Science Bulletin 1997年第21期42卷 1787-1792页

作者： Luo, GP Wu, hm Wang, m Zhu, SN Lu, YQ Liu, ZG Wei, Y ming, NB Nanjing Univ Natl Lab Solid State Microstruct Nanjing 210093 Peoples R China

RECENTLY, excimer laser devices, which have higher-energy density output in pulsed ultravio-let (UV) light (193 or 248 nm), have been employed to generate some thin film struc-tures. The principle of this technique, which is also called pulsed laser deposition (PLD)technique, is that the exposed material could be ablated out of the sample by the focusing laserbeam, and redeposit on a substrate to form thin-film structures under certain conditions. Onthe other hand, researchers have obtained high-quality Bragg gratings in photosensitive

关键词： excimer laser pulse phase mask grating periodic surface structures.

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A Whitecap Coverage model Based on the Surface Slope For Criterion of Wave Breaking

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China Ocean Engineering 1998年第1期13卷 73-85页

作者： Xu, DL Yu, DY Lu, hm Ocean Univ Qindao Phys Oceanog Lab Qingdao 266003 Peoples R China Ocean Univ Qindao Sch Engn Qingdao 266003 Peoples R China

Using the limit surface slope as a criterion of wave breaking, a simple model for estimating the spatial fraction of breaking surface of sea at an instant, which is regarded as the whitecap coverge in this paper, is analytically derived from the probability density of surface slope based on Gaussian statistics. The resulting fraction is found depending on the fourth moment of wave spectum, m(4), as well as the critical threshold of surface slope. By expressing the fourth moment in terms of the Neumann spectrum, a formula linking the fraction and wind speed for fully developed sea states is obtianed. Another formula relating the fraction to both wind speed and fetch (or duration) is achieved by expressing m, in terms of the Krylov spectrum and applying the empirical relationships used in the SmB ocean wave predicting technique. A comparison between these results and the field data of whitecap coverage collected by monahan and O'muircheartuigh shows an encouraging agreement.

关键词： whitecap coverage criterion of wave breaking wind speed wind fetch wind duration fully developed sea state fetch-limited sea state

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Exploring tree diversity and stand structure of savanna woodlands in southeastern Sudan

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Journal of Arid Land 2020年第4期12卷 609-617页

作者： Ahmed m m HASOBA Ahmed A H SIDDIG Yousif E YAGOUB Faculty of Forest Sciences and Technology University of GeziraMadani 22212Sudan Faculty of Forestry University of KhartoumKhartoum North 13314Sudan Department of Environmental Conservation University of Massachusetts AmherstAmherst 01003USA

Savanna woodlands in Sudan host great biodiversity, provide a plethora of ecosystem goods and services to local communities, and sustain numerous ecological functions. Although the importance of the Acacia trees in these areas is well known, up-to-date information about these woodlands' diversity is limited and changes in their woody vegetation composition, density, diversity and relative frequency are not monitored over time. This study explored tree diversity and stand stage structure in Nuara Reserved Forest, a typical savanna woodland ecosystem in southeastern Sudan. A total of 638 circular sample plots(1000 m^2 for each) were established using a systematic sampling grid method. The distance between plots was 200 m. In each plot, all living trees with diameter at breast height(DBH) ≥5.00 cm were identified and counted, and their DBH values were recorded. From these data, tree composition, diversity, density and stage structure were assessed. There were 12,259 individual trees representing four species(Acacia seyal, Balanites aegyptiaca, Acacia Senegal and Acacia mellifera) that belong to two families. The dominant species was Acacia seyal. Average tree density was 191 trees/hm^2 and the Shannon-Weiner index for trees diversity was 0.204. Overall, young trees comprised 86.30% of the forest. The state of tree richness and density in the study area was low compared to other similar environments in the region and around the world. We recommended adoption of a proper management system that includes monitoring of woody vegetation diversity in this forest, and management actions to enhance tree diversity and sustain ecosystem services to local communities. In addition to care for the dominant Acacia seyal stands, more attention and conservation should be devoted to reestablishing Acacia senegal and Acacia mellifera trees because of their high ecological and economic values for local communities.

关键词： species diversity stand structure savanna woodland ecosystem forest monitoring forest management ecosystem services Nuara Reserved Forest

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Correction of failure in antenna array using matrix pencil technique

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Chinese Physics B 2017年第6期26卷 491-498页

作者： S U Khan m K A Rahim Advanced RF & microwave Research Group Department of Communication Engineering Faculty of Electrical Engineering Universiti Teknologi Malaysia 81310 Skudai Johor Malaysia

In this paper a non-iterative technique is developed for the correction of faulty antenna array based on matrix pencil technique（mPT）. The failure of a sensor in antenna array can damage the radiation power pattern in terms of sidelobes level and nulls. In the developed technique, the radiation pattern of the array is sampled to form discrete power pattern information set. Then this information set can be arranged in the form of Hankel matrix（hm） and execute the singular value decomposition（SVD）. By removing nonprincipal values, we obtain an optimum lower rank estimation of hm. This lower rank matrix corresponds to the corrected pattern. Then the proposed technique is employed to recover the weight excitation and position allocations from the estimated matrix. Numerical simulations confirm the efficiency of the proposed technique, which is compared with the available techniques in terms of sidelobes level and nulls.

关键词： array correction low rank estimation matrix pencil technique singular value decomposition

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