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In situ selective laser gas nitriding for composite TiN/Ti-6Al-4V fabrication via laser powder bed fusion

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Journal of Materials science & Technology 2020年第10期42卷 98-107页

作者： P.A.Morton H.C.Taylor L.e.Murr O.G.Delgado C.A.Terrazas R.B.Wicker W.M.Keck Center for 3D Innovation The University of Texas at El PasoEl PasoTX79968USA Department of Mechanical engineering The University of Texas at El PasoTX 79968USA Department of Metallurgical Materials and Biomedical EngineeringThe University of Texas at El PasoTX 79968USA

Laser-assisted gas nitriding of selective Ti-6Al-4V surfaces has been achieved during laser powder bed fusion fabrication by exchanging the argon build gas environment with *** variation of processing parameters allowed microdendritic Ti N surface coatings to be formed having thicknesses ranging from a few tens of microns to several hundred microns,with TiN dendrite microstructure volume fractions ranging from 0.6 to 0.75;and corresponding Vickers microindentation hardness values ranging from^7.5 GPa–9.5 *** TiN hard layers ranging from 50μm to 150μm thick were also fabricated in the laser-beam additively manufactured Ti-6Al-4V alloy producing prototype,hybrid,planar composites having alternating,ductile Ti-6Al-4V layers with a hardness of^4.5 GPa and a stiff,TiN layer with a hardness of^8.5 *** results demonstrate prospects for fabricating novel,additively manufactured components having selective,hard,wear and corrosion resistant coatings along with periodic,planar or complex metal matrix composite regimes exhibiting superior toughness and related mechanical properties.

关键词： Ti-6Al-4V TiN ceramic coatings and embedded layers Dendritic microstructures selective laser melting Additive manufacturing Metal matrix composites selective nitriding

sclerotia Formation and Toxin Production in Large sclerotial Aspergillus flavus Isolates from Kenya

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Advances in Microbiology 2016年第1期6卷 47-56页

作者： s. A. Okoth B. Nyongesa V. Joutsjoki H. Korhonen V. Ayugi e. K. Kang’ethe school of Biological sciences University of Nairobi Nairobi Kenya Natural Resources Institute Finland Jokioinen Finland Department of Public Health Pharmacology and Toxicology University of Nairobi Nairobi Kenya

We studied the relationship between sclerotia formation and aflatoxin production by Aspergillusflavus strains isolated from maize kernels from Nandi County. Isolates recovered from maize kernels were tested for their ability to form sclerotia on different growth media. PCR analysis was done on the isolates to detect 2 structural genes, aflD and aflQ, involved in aflatoxin biosynthesis pathway. Positive A. flavus isolates for one or both genes were grown on Yeast extract sucrose Agar medium and aflatoxins quantified using LCMsMs. All the isolates formed large sclerotia and their formation was influenced by media type but could not be related to amount of aflatoxins produced both in vivo and in vitro. Though sclerotia are perennating structures and so contribute to survival index of a fungus, their initiation is regulated by external factors though ability to form is genetic. This brings ambiguity of their presence or abundance as a measure of toxicity.

关键词： sclerotia Aflatoxins Maize Kenya Aspergillus flavus

Dating long thrust systems on Mercury:New clues on the thermal evolution of the planet

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Geoscience Frontiers 2020年第3期11卷 855-870页

作者： L.Giacomini M.Massironi V.Galluzzi s.Ferrari P.Palumbo INAF-IAPs Istituto di Astrofisica e Planetologia SpazialiVia Fosso Del Cavaliere 100Rome00133Italy Dipartimento di Geoscienze University of PadovaVia G.Gradenigo 6Padova35131Italy Center of studies and Activities for space(CIsAs)“G.Colombo” University of PadovaVia Venezia 15Padova35131Italy Dipartimento di scienze e Tecnologie University of Naples“Parthenope”Centro DirezionaleIsola C4Napoli80143Italy

The global tectonics of Mercury is dominated by contractional features mainly represented by lobate scarps,high relief ridges,and wrinkle *** structures are the expression of thrust faults and are linear or arcuate features widely distributed on ***,these structures are arranged in long systems characterized by a preferential orientation and non-random spatial *** this work we identified five thrust systems,generally longer than 1000 *** were named after the main structure or crater encompassed by the system as:Thakur,Victoria,Villa Lobos,Al-Hamadhani,and *** order to gain clues about their formation,we dated them using the buffered crater counting technique,which can be applied to derive the ages of linear landforms such as faults,ridges and *** estimate the absolute age for the end of the thrust system's activity,we applied both Le Feuvre and Wieczorek Production Function and Neukum Production ***,to further confirm the results obtained with the buffered crater counting method,the classic stratigraphic approach has been adopted,in which a faulted and an unfaulted craters were dated for each *** results gave consistent ages and suggested that the most movements along major structures all over Mercury most likely ended at about 3.6-3.8 *** gives new clues to better understand the tectonics of the planet and,therefore,its thermal ***,the early occurrence of tectonic activity in the planet's history,well before than predicted by the thermophysical models,coupled with the orientation and spatial distribution of the thrust systems,suggests that other processes beside global contraction,like mantle downwelling or tidal despinning,could have contributed to the first stage of the planet's history.

关键词： Mercury Thrust systems Crater counting Thermal evolution Planetary geology structural geology

strength-ductility synergy in a 1.4 GPa austenitic steel with a heterogeneous lamellar microstructure

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Journal of Materials science & Technology 2022年第11期106卷 133-138页

作者： Gang Niu Hatem s.Zurob R.D.K.Misra Huibin Wu Yu Zou Department of Materials science and engineering University of TorontoTorontoONM5S 3E4Canada Collaborative Innovation Center of Steel TechnologyUniversity of Science and Technology BeijingBeijing 100083China Department of Materials science and engineering McMaster UniversityHamiltonONL8S 4L7Canada Department of Metallurgical Materials and Biomedical EngineeringUniversity of Texas at El PasoEl PasoTX 79968USA Collaborative Innovation Center of steel Technology University of Science and Technology BeijingBeijing 100083China Department of Materials science and engineering University of TorontoTorontoONM5S 3E4Canada

*** Advanced high-strength steels with good ductility are essen-tial to the manufacturing,structural safety,and light-weighting of load-bearing structures in many industries[1-3].Austenitic stain-less steel(Ass)exhibits high ductility due to the TRIP and/or TWIP effect that can alleviate stress concentration,prevent void nucle-ation,enhance work hardening,and postpone necking[4-6].The yield strength of conventional Ass is generally low(∼200-500 MPa),and their deformation resistance is insufficient for many load-bearing applications[6].Previous studies reported the in-creased yield strength in various austenitic steels through grain refinement,dislocation strengthening,precipitation strengthening,and heterogeneous hardening[7-14].A single strengthening mech-anism,however,is typically insufficient to obtain ultrahigh yield strength over 1 GPa in austenitic steel[12].

关键词： steel ductility austenitic

spectrophotometric Determination of Compex Formation of Cerium（Ⅲ） with 1-phenyl-2,3-dimethylpyrazolone-5-azo-4-pyrogallole in the Presence of Cetylpyridine Chloride

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Journal of Chemistry and Chemical engineering 2010年第10期4卷 62-64页

作者： R.A. Aliyeva s.R. Gadjiyeva F.e. Huseynov M.T. Akhundova F.M. Chiragov Chemistry Department Baku State University Baku Z. Khalilov 23 4z 1148 Azerbaijan

Complex formation of cerium （Ⅲ） with l-phenyl-2,3-dimethylpyrazolone-5-azo-4-pyrogallole （L） in the presence and absence ofcetylpyridine chloride （CPC） was investigated. Homogeneous CeL- and mixed ligand CeL-CPC compounds are formed at pH 6. Constants of stability of the complexes are （IgKD 5.15±0.02 （CeL）, 7.98±0.03 （CeL-CPC）. Ratio of reagents in composition of homogeneous is （1 ：2） and in different ligand it equals to （1：2：2）. Beer＇s law is observed in interval of concentration 1.12-11.2 μg/ml Ce. The technique for photometric determination of cerium was worked out in artificial mixture.

关键词： Cerium azoderivatives of pyragollole cetylpyridine chloride photometric determination.

stromal and Tumor Glioma-derived Cells with similar Characteristics Have Differences in α-smooth Muscle Actin expression and Localization

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Journal of Oncology Research 2021年第2期3卷 8-21页

作者： I.Gin I.Chistyakova V.Zenin s.Koshkin A.Musorina Y.Lahina G.Timin V.Pospelov s.Prikhodko A.Petukhov e.Tolkunova Institute of Cytology Russian Academy of SciencesSt.Petersburg194064Russia Almazov National Medical Research Centre St.Petersburg197341Russia Peter the Great saint-Petersburg Polytechnic University St.Petersburg195251Russia scientific Technological University«sirius» Sochi354340Russia

Gliomas are solid brain tumors composed of tumor cells and recruited heterogenic stromal *** study of the interactions between the perivascular niche and its surrounding cells is of great value in unraveling mechanisms of drug resistance in malignant *** this study,we isolated the stromal diploid cell population from oligodendroglioma and a mixed population of tumor aneuploid and stromal diploid cells from astrocytoma *** stromal cells expressed neural stem/progenitor and mesenchymal markers showing the same discordant phenotype that is typical for glioma ***,some of the stromal cells expressed *** the first time,we demonstrated that this type of stromal cells had the typical myofibroblastic phenotype as theα-sMA+cells formedα-sMA fibers and exhibited the specific function to deposit extracellular matrix(eCM)proteins at least in *** analysis showed diffuse or focalα-sMA staining in the cytoplasm of the astrocytoma-derived,A172,T98G,and U251MG glioma *** could suggest thatα-sMA may be one of the main molecules,bearing protective *** mechanisms and consequences ofα-sMA disruptions in gliomas are discussed.

关键词： Oligodendroglioma Astrocytoma Primary cell cultures Tumor microenvironment Myofibroblasts extracellular matrix

Comparison between the theoretical models and experimental structures of some oc tacoordinated Ln(Ⅲ)-bis-dipyridyl-bis-dichloroacetato-diaquo complexes and their phenanthroline analogues

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Journal of Rare earths 2010年第S1期28卷 83-85页

作者： s. P. sINHA Alfredo M. sIMAs Gustavo L. C. MOURA sRD 6565 Willowick Pl.DaytonOHIO 45459-3005U.S.A. Departamento de Quimica Fundamental CCENUniversidade Federal de Pernambuco50590-470Recif ePEBrazil

The title complexes were modeled using the semiempirical MOPAC and the newly developed sPARKLe paramerters of the lanthanides. The calculated bond dis tances and angles agreed well with those found from crystal structure measuremen ts. This technique allows us to screen a large number of molecules and get struc tural information within a very short time.

关键词： lanthanide complex theoretical models octacoordination dipyridyl p henanthroline MOPAC sPARKLe rare earths

An Approach to Quantify the Heat Wave strength and Price a Heat Derivative for Risk Hedging

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Advances in Atmospheric sciences 2012年第1期29卷 1-9页

作者： samuel s. P.sHeN Benedikt KRAMPs shirley X.sUN Barbara BAILeY Department of Mathematics and statistics San Diego State University

Mitigating the heat stress via a derivative policy is a vital financial option for agricultural producers and other business sectors to strategically adapt to the climate change scenario. This study has provided an approach to identifying heat stress.events and pricing the heat stress weather derivative due to persistent days of high surface air temperature （sAT）. Cooling degree days （CDD） are used as the weather index for trade. In this study, a call-option model was used as an example for calculating the price of the index. Two heat stress indices were developed to describe the severity and physical impact of heat waves. The daily Global Historical Climatology Network （GHCN-D） sAT data from 1901 to 2007 from the southern California, UsA, were used. A major California heat wave that occurred 20-25 October 1965 was studied. The derivative price was calculated based on the call-option model for both long-term station data and the interpolated grid point data at a regular 0.1~ x0.1~ latitude-longitude grid. The resulting comparison indicates that （a） the interpolated data can be used as reliable proxy to price the CDD and （b） a normal distribution model cannot always be used to reliably calculate the CDD price. In conclusion, the data, models, and procedures described in this study have potential application in hedging agricultural and other risks.

关键词： heat derivative price heat wave risk cooling degree day call option payoff southern California

Recombinant human C1 inhibitor for the prophylaxis of hereditary angioedema attacks: a pilot study

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世界最新医学信息文摘 2014年第7期 3-4页

作者： A.Reshef D.Moldovan K.Obtulowicz I.Leibovich e.Mihaly s.Visscher A.Relan

Background Hereditary angioedema (HAe) is a disease characterized by recurrent tissue swelling affecting various body locations. Recent literature shows that patients with frequent attacks may benefit from long-term prophylaxis. This study evaluated the safety and prophylactic effect of weekly administrations of recombinant C1INH (rhC1INH).Methods Patients with a history of HAe attacks occurring ≥every 2 weeks received a once weekly administration of 50 U/kg *** angioedema attack history was collected at screening. Breakthrough attacks during the study were recorded at each visit. Following a 2-week run-in period, HAe patients received 8 weekly rhC1INH administrations and were followed-up for an additional 6 weeks. efficacy was evaluated by comparing the HAe attack incidence during the treatment period to the historical attacks over the previous 2 years. safety evaluation was based on clinical laboratory and adverse events (Aes) *** The 25 participants reported a mean of 0.9 attacks/week over the past 2 years. The mean breakthrough attack rate during the treatment period was 0.4 attacks/week (95% CI 0.28–0.56). A total of 30 treatment-emergent-Aes were reported in 13 patients,all mild to moderate. One patient died from a laryngeal attack 25 days after last study drug administration. The only possible drug related Aes reported were dry mouth, dizziness and anxiety in one patient and hypotension in another. There were no allergic Aes and no neutralizing antibodies *** Weekly administrations of 50 U/kg rhC1INH appeared to reduce the frequency of HAe attacks and were generally safe and well tolerated.

关键词： INH HAe a pilot study Recombinant human C1 inhibitor for the prophylaxis of hereditary angioedema attacks