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The Role of Nanodispersed Nitrides in the Sintering of Silicon Nitride Ceramics

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Plasma Science and Technology 2010年第1期12卷 46-48页

作者： m.georgieva G.VISSOKOV I.GRANCHAROV R.F.SILVA F.J.OLIVEIRA Department of Technology of Inorganic Substances University of Chemical Technology and Metallurgy Institute of Catalysis Bulgarian Academy of Sciences Ceramics and Glass Eng. Department CICECO University of Aveiro

The synthesis of ceramics based on silicon nitride using nanopowders of TiN and Si3N4 as additives was studied. The ceramic compositions were pressurelessly sintered under ni- trogen atmosphere at different temperatures （1550℃, 1650℃ and 1750℃） with a heating rate of 10℃/min and a holding time of 2 h. The nanodispersed nitrides （NDN） were produced by electric-arc plasma synthesis and characterized. The ceramic composites obtained with nanoparticles of 1wt% to 5wt% TiN and 20wt% Si3N4 were characterized by scanning electron microscopy （SEm）, atom force microscopy （AFm） and energy-dispersive spectrometry （EDX）. The effect of the addition of nanodispersed powders on the mechanical properties and microstructure of Si3N4 ceramics was investigated.

关键词： silicon nitride ceramics nanocomposites nanopowders

Dual-polarization multiplexing amorphous Si:H grating couplers for silicon photonic transmitters in the photonic BiCmOS backend of line

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Frontiers of Optoelectronics 2022年第1期15卷 143-155页

作者： Galina georgieva Christian mai Pascal m.Seiler Anna Peczek Lars Zimmermann Hochfrequenztechnik-Photonik/Siliziumphotonik Technische Universität BerlinStraße des 17.Juni 13510623 BerlinGermany IHP-Leibnitz Institut für innovative mikroelektronik Im Technologiepark 2515236 Frankfurt(Oder)Germany IHP Solutions GmbH Im Technologiepark 715236 Frankfurt(Oder)Germany

In this paper,we report on polarization combining two-dimensional grating couplers(2D GCs)on amorphous Si:H,fabricated in the backend of line of a photonic BiCmOS *** 2D GCs can be used as an interface of a hybrid silicon photonic coherent transmitter,which can be implemented on bulk Si *** fabricated 2D GCs operate in the telecom C-band and show an experimental coupling efficiency of−5 dB with a wafer variation of±1.2 *** for efficiency enhancement and improved performance stability in future design generations are outlined and extension toward O-band devices is also investigated.

关键词： Hybrid integration Photonic BiCmOS Amorphous silicon Two-dimensional grating coupler(2D GC) Dual-polarization coherent communication Silicon photonics

High-Temperature Thermodynamic Investigation of Nano-Dispersed Nitrides Obtained in Thermal Plasma

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Plasma Science and Technology 2007年第2期9卷 174-176页

作者： m. georgieva G. VISSOKOV Iv. GRANCHAROV L. BRAKALOV Department of Technology of Inorganic Substances University of Chemical Technology andMetal|urgy 8 K. Okhridski Blvd. 1756 Sofia Bulgaria

The nitrides of transient metals have a high hardness, thermal stability, remarkable wear resistance in aggressive chemical mediums, melted metals and alloys, high corrosion resistance, and low coefficient of electric resistance. Under the conditions of low-temperature argon plasma （LTP）, thermodynamic investigations were conducted in the process of obtaining of A1N, TiN and Si3N4 in a temperature range of 1000 K to 6000 K. To investigate the thermodynamic possibility of obtaining nitrides, a computer model was used which provided the equilibrium composition of gaseous and solid phases at different temperatures. The conditions for chemical equilibrium of the system were based on the minimization of Gibbs＇ energy.

关键词： plasma-chemical treatment nitrides thermodynamic analysis

Toward coherent O-band data center interconnects

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Frontiers of Optoelectronics 2021年第4期14卷 414-425页

作者： Pascal m.SEILER Galina georgieva Georg WINZER Anna PECZEK Karsten VOIGT Stefan LISCHKE Adel FATEmI Lars ZImmERmANN Technische Universität Berlin Chair of SiliziumphotonikBerlin 10623Germany IHP–Leibniz-Institut für innovative mikroelektronik Frankfurt(Oder)15236Germany Technische Universität Berlin Chair of Hochfrequenztechnik-PhotonikBerlin 10623Germany IHP Solutions GmbH Frankfurt(Oder)15236Germany

Upcoming generations of coherent intra/inter data center interconnects currently lack a clear path toward a reduction of cost and power consumption,which are the driving factors for these data *** this work,the tradeoffs associated with a transition from coherent C-band to O-band silicon photonics are addressed and *** discussion includes the fundamental components of coherent data links,namely the optical components,fiber link and *** a major component of these links,a monolithic silicon photonic BiCmOS O-band coherent receiver is evaluated for its potential performance and compared to an analogous C-band device.

关键词： coherent communication data center O-band silicon photonics

Particle formulation of hydroalcoholic rosemary (Rosmarinus officinalis L.) extracts using a spouted bed

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Particuology 2020年第4期18卷 26-34页

作者： D.Peshev E.Eichner m.Goslinska S.Pietsch Y.Trambabova T.Terzieva N.georgieva S.Heinrich Department of Chemical Engineering University of Chemical Technology and Metallurgy1576 SofiaBulgaria Institute of Solids Process Engineering and Particle Technology Hamburg University of Technology21073 HamburgGermany Department of Biotechnology University of Chemical Technology and Metallurgy1576 SofiaBulgaria

In this study,spouted bed technology was applied to the protection and functionalization of polyphenolic rosemary ***,solid-liquid extraction was performed at 25℃with *** ethanol-water ratio was chosen to obtain high phenolic acid and diterpene concentrations in the *** selected solvent composition gave liquid extracts that could be directly added to a coating mixture for feeding into a spouted bed ***,no preliminary solvent exchange or evaporation of the extraction solvent to dryness was *** grade Paselli mD 6 maltodextrin and HiCap 100 modified starch were used as inert core and shell materials in the spouted bed encapsulation process under mild operating *** antioxidant activity of the fresh extract was retained during processing,which indicated that the active constituents were preserved and quantitatively transferred into the encapsulated formulations,which were readily soluble in *** obtained powders were composed of nearly spherical *** compositions,water solubilities,and particle morphologies make them a strong candidate for food and beverage applications as natural antioxidants,preservatives,or functional ingredients.

关键词： Particle Polyphenolic rosemary extract Encapsulation Spouted bed Bioactive Antioxidant

On the diversity of fungi from soda soils

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Fungal Diversity 2016年第1期76卷 27-74页

作者： Alexey A.Grum-Grzhimaylo marina L.georgieva Sofiya A.Bondarenko Alfons J.m.Debets Elena N.Bilanenko Laboratory of Genetics Plant Sciences GroupWageningen UniversityDroevendaalsesteeg 16708 PB WageningenThe Netherlands Gause Institute of New Antibiotics Federal State Budgetary Scientific InstitutionBol’shaya Pirogovskaya 11119021 MoscowRussia Faculty of Biology Lomonosov Moscow State UniversityLeninskie Gory 1-12119234 MoscowRussia

The diversity of filamentous fungi that can grow at high ambient pH values(i.e.,8–11)remains largely *** we study 100 alkalitolerant and alkaliphilic isolates from the soils around the basin of soda lakes in Asia and Africa to assess the major evolutionary lineages and morphologies pertinent to the alkaliphilic trait in filamentous *** Emericellopsis lineage(Hypocreales,Hypocreomycetidae),along with Plectosphaerellaceae(Hypocreomycetidae),Pleosporaceae(Dothideomycetes),Chaetomiaceae(Sordariomycetidae)families appeared to be overrepresented with strong alkalitolerants and effective *** particular,Sodiomyces species(Plectosphaerellaceae),Acrostalagmus luteoalbus(Plectosphaerellaceae),Emericellopsis alkalina(Hypocreales),Thielavia sp.(Chaetomiaceae),and Alternaria ***(Pleosporaceae)grew best at high ambient *** pH tolerance of Chordomyces antarcticum,Acrostalagmus luteoalbus and some other species was largely affected by the presence of extra Na+in the growth *** alkalitolerants included Scopulariopsis members(microascales),Fusarium,Cladosporium,and many asexual acremonium-like species from *** alkalitolerants were represented by sporadic isolates of Penicillium,Purpureocillium lilacinum,and Alternaria alternata species,with the growth optimum at neutral or acidic *** alkalitolerants develop loose dry chains of spores easily dispersed by *** presence at low frequency with the growth optimum at neutral or acidic pH leads us to treat them as transient species in the alkaline soils,as those are also ubiquitous saprobes in normal *** phylogenetic analyses show that the alkaliphilic trait in filamentous fungi has evolved several *** lineages harboring strong alkalitolerants derived from the known marine-borne fungi(Emericellopsis,Alternaria ***),or fall within the fungi associated with halophytic grasses(Pleosporaceae).Soda soils contain a diversity of fungi that ra

关键词： Alkaliphilic fungi pH Soda soils Extremophile Sodiomyces Acrostalagmus Chordomyces Verticillium Emericellopsis Acremonium Scopulariopsis Alternaria Thielavia Plectosphaerellaceae Pleosporaceae

Schiff base SH11 with tuberculostatic and radical scavenging activities against INH-induced oxidative hepatic damage

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Advances in Bioscience and Biotechnology 2012年第7期3卷 1068-1075页

作者： Nedyalka georgieva Zvezdelina Yaneva Galina Nikolova Svetlana Simova Department of medical Chemistry and Biochemistry Faculty of Medicine Trakia University Stara Zagora Bulgaria Department of Pharmacology Animal Physiology and Physiological Chemistry Faculty of Veterinary Medicine Trakia University Students Campus Stara Zagora Bulgaria Institute of Organic Chemistry Bulgarian Academy of Sciences Sofia Bulgaria

By in vitro visible electron paramagnetic resonance (EPR) spectrophotometry method we demonstrated that N-isonicotinoyl-N’-(3-etoxy-2-hydroxybenzaldehyd) hydrazone (SH11) exhibits radical scavenging activity (SSA). malondialdehyde (mDA) in mice treated with INH was increased (2.578 ± 0.349 mm vs. 2.024 ± 0.164 μm, p SOD/mg Pr vs. 2.273 ± 0.317 USOD/mg Pr, p CAT/mg Pr, vs. 47.070 ± 16.490 UCAT/mg Pr, p mpared to the untreated controls. The combination INH + SH11 (30 mg/kg p.o.) showed reduced levels of mDA, compared to the INH-treated (mean 2.291 ± 0.025 μm than 2.578 ± 0.349, p mbination with the lowest reduction of SOD compared to the controls was 151 mg/kg i.p. INH + 30 mg/kg p.o. SH11, but there was a significant difference in SOD activities between the group treated with this combination and the untreated controls (p most effective combination, with CAT levels, close to the controls was 151 mg/kg i.p. INH + 30 mg/kg p.o. SH11.

关键词： INH Schiff Base Tuberculosis EPR Lipid Peroxidation Antioxidant Enzymes

macular morphology in Patients with Retinopathy of Prematurity

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Open Journal of Ophthalmology 2020年第1期10卷 59-68页

作者： Silviya Krumova Desislava Voynikova Desislava Koleva-georgieva Vasil marinov Nelly Sivkova Department of Ophthalmology Faculty of Medicine Medical University of Plovdiv Plovdiv Bulgaria University of Plovdiv “Paisii Hilendarski” Plovdiv Bulgaria

Purpose: To investigate macular morphology by spectral domain optical coherence tomography (SDOCT) in children with history of the retinopathy of prematurity (ROP). materials and methods: In this cross-sectional study we included 35 eyes of 18 patients, aged 4 to 8 years, with history of ROP. Twenty-one eyes had received treatment for type 1 pre-threshold ROP. The others showed spontaneous regression of the disease. A 7 × 7-mm retinal area was sampled using a 3-dimensional scanning protocol with high-resolution spectral domain optical coherence tomography (SOCT Copernicus REVO). The central foveal thickness, mean macular thickness, macular volume and foveal depression were measured. The macular anatomy and the foveal contour were examined. Results: The mean birth weight was 1338.29 ± 324.05 grams. mean gestational age at birth was 29.37 ± 2.07 weeks. Twenty-one eyes were treated with laser or cryotherapy. All of them showed regression of the disease. The mean best corrected visual acuity was 20/28. The average central foveal thickness was 262.26 ± 37.39, with 68.57% of preterm > 240 μm and 22.86% > 220 μm. In all eyes, the foveal contour is abnormal. A foveal depression was absent in 25 eyes (71%). Conclusion: In the majority of children with a history of ROP, we found changes in macular morphology, including retention of inner retinal layers and absent foveal depression. In our study foveal hypoplasia was associated with good functional outcome.

关键词： Foveal Pit macular morphology Optical Coherence Tomography Preterm Visual Acuity

Effects of carob-bean gum thickened formulas on infants' reflux and tolerance indices

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World Journal of Clinical Pediatrics 2016年第1期5卷 118-127页

作者： miglena georgieva Yannis manios Niya Rasheva Ruzha Pancheva Elena Dimitrova Anne Schaafsma Second Pediatric Clinic University Hospital "St. Marine" Department of Nutrition and Dietetics Harokopi University of Athens Department of Hygiene Medical University Friesland Campina

AIm: To examine the effect of carob-bean gum(CBG) thickened-formulas on reflux and tolerance indices in infants with gastro-esophageal reflux(GER). mETHODS: Fifty-six eligible infants(1-6 mo old) were randomly allocated to receive for two weeks a formula with either 0.33 g/100 m L(Formula A) or 0.45 g/100 m L(Formula B) of cold soluble CBG galactomannans respectively, or a formula with 0.45 g/100 m L of hot soluble CBG galactomannans(Formula C). No control group receiving standard formula was included in the study. Data on the following indices were obtained both at baseline and follow-up from all study participants: 24 h esophageal p H monitoring indices, anthropometrical indices(i.e., body weight and length) and tolerance indices(i.e., frequency of colics; type and frequency ofdefecations). From the eligible infants, forty seven were included in an intention-to-treat analysis to examine the effects of the two-week trial on esophageal 24 h p H monitoring, growth and tolerance indices. Repeated measures ANOVA was used to examine the research ***: Regarding changes in 24 h p H monitoring indices, significant decreases from baseline to followup were observed in the "Boix Ochoa Score"(i.e., an index of esophageal acid exposure), in the total number of visible refluxes and in all symptoms related indices due to acid reflux only for infants provided with Formula A, while no significant changes were observed for infants provided with Formulas B and C. In addition, the significant decreases observed in two symptoms related p H monitoring indices(i.e., "Symptom index for reflux" and "Percentage of all reflux") for infants provided with Formula A were also found to differentiate significantly compared to the changes observed in the other two groups(P = 0.048 and P = 0.014 respectively). Concerning changes in anthropometric indices, body weight significantly increased among infants provided with Formulas A and C, but not for infants provided with Formula B. As

关键词： Reflux Carob bean gum Galactomannans Infants Formula