检索结果-南通市图书馆

Energy and blast performance of beryllium in a model thermobaric composition in comparison with aluminum and magnesium

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Defence Technology（防务技术） 2024年第6期36卷 13-19页

作者： Thomas M.Klapotke Stanisław Cudziło Waldemar A.Trzcinski jozef Paszula Energetic Materials Research Department of ChemistryUniversity of Munich(LMU)Butenandtstrasse 5-13(D)81377MunichGermany Military University of Technology Faculty of Advanced Technologies and ChemistrySylwester Kaliski Str.200-908WarsawPoland

A direct comparison is made between the effectiveness of Al,Mg,and Be powders as additional fuels in model thermobaric compositions containing 20%fuel,20%ammonium perchlorate,and 60%RDX(1,3,5-Trinitro-1,3,5-triazacyclohexane)passivated with *** determined calorimetric measurements of the heat of detonation,along with the overpressure histories in an explosion chamber filled with nitrogen,were used to determine the quasi-static pressure(QSP)under anaerobic *** measurements were also performed in a semi-closed bunker,and all blast wave parameters generated after the detonation of 500 g charges of the tested explosives were *** calorimetry results,QSP values,and blast wave parameters(pressure amplitude,specific and total impulses)clearly indicate that Be is much more effective as an additional fuel than either Al or Mg in both anaerobic post-detonation reactions as well as the subsequent aerobic *** heat of detonation of the RDXwax/AP/Be explosive mixture is over 40%and 50%higher than that of the mixture containing aluminum and magnesium instead of beryllium,***,the TNT equivalent of the Be-containing composition due to the overpressure in the nitrogen-filled explosion chamber is 1.66,while the equivalent calculated using an air shock wave-specific impulse at a distance of 2.5 m is equal to *** high values of these parameters confirm the high reactivity of beryllium in both the anaerobic and aerobic stages of the thermobaric explosion.

关键词： Thermobaric explosives Beryllium Heat of detonation Quasi-static overpressure Blast wave parameters

In-situ study of the microstructure evolution during tension of a Mg-Y-Zn-Al alloy processed by rapidly solidified ribbon consolidation technique

在线全文

学校读者我要写书评

暂无评论

Journal of Magnesium and Alloys 2024年第5期12卷 2024-2040页

作者： Jeno Gubicza Kristián Máthis Péter Nagy Péter Jenei Zoltán Hegedus Andrea Farkas jozef Vesely Shin-ichi Inoue Daria Drozdenko Yoshihito Kawamura Department of Materials Physics Faculty of ScienceEotvos Loránd UniversityPázmány P.sétány 1/ABudapest H-1117Hungary Department of Physics of Materials Faculty of Mathematics and PhysicsCharles UniversityKe Karlovu 512116 Praha 2Czech Republic Deutsches Elektronen-Synchrotron DESY Notkestr.85Hamburg 22603Germany Magnesium Research Center Kumamoto University2-39-1 KurokamiChuo-kuKumamoto 860-8555Japan

Mg-Y-Zn-Al alloys processed by rapidly solidified ribbon consolidation(RSRC)technique exhibit an exceptional mechanical performance indicating promising application *** material has a bimodal microstructure consisting of fine recrystallized and coarse non-recrystallized grains with solute-rich stacking faults forming cluster arranged layers(CALs)and nanoplates(CANaPs),or complete long period stacking ordered(LPSO)*** order to reveal the deformation mechanisms,in-situ synchrotron X-ray diffraction line profile analysis was employed for a detailed study of the dislocation arrangement created during tension in Mg-0.9%Zn-2.05%Y-0.15%Al(at%)*** uncovering the effect of the initial microstructure on the mechanical performance,additional samples were obtained by annealing of the as-consolidated specimen at 300 and 400℃ for 2 *** heat treatment at 300℃ had no significant effect on the initial microstructure,its evolution during tension and,thus,the overall deformation behavior under tensile *** the other hand,annealing at 400℃ resulted in a significant increase of the recrystallized grains fraction and a decrease of the dislocation density,leading to only minor degradation of the mechanical *** maximum dislocation density at the failure of the samples corresponding to the plastic strain of 10-25% was estimated to be about 16-20×10^(14)m^(-2).The diffraction profile analysis indicated that most dislocations formed during tension were of non-basal and pyramidal types,what was also in agreement with the Schmid factor values revealed independently from orientation *** was also shown that the dislocation-induced Taylor hardening was much lower below the plastic strain of 3% than above this value,which was explained by a model of the interaction between prismatic dislocations and CANaPs/LPSO plates.

关键词： Mg-Zn-Y-Al alloy Long period stacking ordered(LPSO)phase Cluster arranged nanoplates(CANaPs) Annealing Tension Dislocation density Hardening

Ce对Al-Si-Cu合金中a(Al)-Al_(2)Cu共晶形貌的影响(英文)

在线全文

学校读者我要写书评

暂无评论

Transactions of Nonferrous Metals Society of China 2014年第1期24卷 36-41页

作者： Maja VONCINA jozef medved Tonica BONCINA Franc ZUPANIC Department for Materials and Metallurgy Faculty of Natural Science and EngineeringUniversity of LjubljanaAskerceva 12SI-1000 LjubljanaSlovenia University of Maribor Faculty of Mechanical EngineeringSmetanova 17SI-2000 MariborSlovenia

关键词： Al-Si-Cu合金共晶显微组织聚焦离子束

Small-extracellular vesicles and their microRNA cargo from porcine follicular fluids:the potential association with oocyte quality

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Animal Science and Biotechnology 2022年第6期13卷 1727-1742页

作者： Ahmed Gad Matej Murin Alexandra Bartkova Veronika Kinterova Katerina Marcollova jozef Laurincik Radek Prochazka Institute of Animal Physiology and Genetics Czech Academy of Sciences27721 LiběchovCzech Republic Department of Animal Production Faculty of AgricultureCairo UniversityGiza 12613Egypt Department of Botany and Genetics Faculty of Natural SciencesConstantine the Philosopher University in Nitra94901 NitraSlovakia.

Background: Ovarian follicular fluids(FFs) contain several kinds of regulatory factors that maintain a suitable micro-environment for oocyte development. Extracellular vesicles(EVs) are among the factors that play essential roles in regulating follicle and oocyte development through their cargo molecules that include microRNAs(miRNAs). This study aimed to investigate small-EV(s-EV) miRNAs in porcine FFs and their potential association with oocyte ***: Individual aspirated oocytes were stained with lissamine green B stain(LB), a vital stain for oocyte quality, and each oocyte was classified as high-quality(unstained;HQ) or low-quality(stained;LQ). FFs corresponding to oocytes were pooled together into HQ and LQ groups. Small-EVs were isolated from FFs, characterized, and their miRNA cargo was identified using the Illumina Nova Seq sequencing platform. Additionally, s-EVs from the HQ and LQ groups were utilized to investigate their effect on oocyte development after co-incubation during in vitro ***: A total of 19 miRNAs(including miR-125b, miR-193a-5p, and miR-320) were significantly upregulated, while 23(including miR-9, miR-206, and miR-6516) were downregulated in the HQ compared to the LQ group. Apoptosis, p53 signaling, and cAMP signaling were among the top pathways targeted by the elevated miRNAs in the HQ group while oocyte meiosis, gap junction, and TGF-beta signaling were among the top pathways targeted by the elevated miRNAs in the LQ group. The supplementation of small-EVs during maturation does not affect the oocyte developmental rates. However, LQ s-EVs increase the proportion of oocytes with homogeneous mitochondrial distribution and decrease the proportion of heterogeneous ***: Our findings indicated that FF-EVs contain different miRNA cargos associated with oocyte quality and could affect the mitochondrial distribution patterns during oocyte maturation.

关键词： Extracellular vesicles Follicular fuids MiRNA Oocyte quality Porcine

Synthesis and crystal structure study of 2′-Se-adenosine-derivatized DNA

在线全文

学校读者我要写书评

暂无评论

Science China Chemistry 2010年第1期53卷 78-85页

作者： SALON jozef Department of Chemistry Georgia State University

The selenium derivatization of nucleic acids is a novel and promising strategy for 3D structure determination of nucleic *** can serve as an excellent anomalous scattering center to solve the phase problem,which is one of the two major bottlenecks in macromolecule X-ray *** other major bottleneck is *** has been demonstrated that the incorporated selenium functionality at the 2′-positions of the nucleosides and nucleotides is stable and does not cause significant structure ***,it was observed that the 2′-Se-derivatization could facilitate crystallization of oligonucleotides with fast crystal growth and high diffraction ***,we describe a convenient synthesis of the 2′-Se-adenosine phosphoramidite,and report the first synthesis and X-ray crystal structure determination of the DNA containing the 2′-Se-A *** 3D structure of 2′-Se-A-DNA decamer 5′-GTACGCGT(2′-Se-A)C-3′2 was determined at 1.75 ? resolution,the 2′-Se-functionality points to the minor groove,and the Se-modified and native structures are virtually ***,we have observed that the 2′-Se-A modification can greatly facilitate the crystal growth with high diffraction *** conjunction with the crystallization facilitation by the 2′-Se-U and 2′-Se-T,this novel observation on the 2′-Se-A functionality suggests that the 2′-Se moiety is sole responsible for the crystallization facilitation and the identity of nucleobases does not influence the crystal growth significantly.

关键词： selenium derivatization nucleic acid adenosine X-ray crystallography structure determination

Basic theorem as representation of heterogeneous concept lattices

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2015年第4期9卷 636-642页

作者： jozef POCS Jana POCSOVA Palacky University Olomouc Department of Algebra and Geometry Olomouc 779 00 Czech Republic Mathematical Institute Slovak Academy of Sciences Kosice 040 01 Slovakia Technical University of Kosice BERG Faculty Institute of Control and Informatization of Production Processes Ko~ice 043 84 Slovakia

We propose a method for representing heteroge- neous concept lattices as classical concept lattices. Particu- larly, we describe a transformation of heterogeneous formal context into a binary one, such that corresponding concept lattices will be isomorphic. We prove the correctness of this transformation by the basic theorem for heterogeneous as well as classical concept lattices.

关键词： basic theorem heterogeneous concept lattice,representation

Impact of Si on the high-temperature oxidation of AlCr(Si)N coatings

在线全文

学校读者我要写书评

暂无评论

Journal of Materials Science & Technology 2022年第5期100卷 91-100页

作者： Nikolaus Jager Michael Meindlhumer Michal Zitek Stefan Spor Hynek Hruby Farwah Nahif Jaakko Julin Martin Rosenthal jozef Keckes Christian Mitterer Rostislav Daniel Christian Doppler Laboratory for Advanced Synthesis of Novel Multifunctional Coatings at the Department of Materials Science Montanuniversität LeobenAustria voestalpine eifeler Vacotec GmbH DüsseldorfGermany Institute of Ion Beam Physics and Materials Research Helmholtz-Zentrum Dresden-RossendorfDresdenGermany Department of Physics University of JyvaskylaFinland European Synchrotron Radiation Facility GrenobleFrance Erich Schmid Institute for Materials Science Austrian Academy of SciencesAustria Department of Materials Science Montanuniversität LeobenAustria

The resistance of wear protective coatings against oxidation is crucial for their use at high ***,three nanocomposite AlCr(Si)N coatings with a fixed Al/Cr atomic ratio of 70/30 and a varying Si-content of 0 at.%,2.5 at.% and 5 at.% were analyzed by differential scanning calorimetry,thermogravimetric analysis and X-ray in order to understand the oxidation behavior depending on their ***,a partially oxidized AlCrSiN coating with 5 at.%Si on a sapphire substrate was studied across the coating thickness by depth-resolved cross-sectional X-ray nanodiffraction and scanning trans-mission electron microscopy to investigate the elemental composition,morphology,phases and residual stress evolution of the oxide scale and the non-oxidized coating *** results reveal enhanced oxidation properties of the AlCr(Si)N coatings with increasing Si-content,as demonstrated by a retarded onset of oxidation to higher temperatures from 1100℃ for AlCrN to 1260℃ for the Si-containing coatings and a simultaneous deceleration of the oxidation *** annealing of the AlCrSiN sample with5 at.%Si at an extraordinary high temperature of 1400℃ for 60 min in ambient air,three zones developed throughout the coating strongly differing in their composition and structure:(i)a dense oxide layer comprising an Al-rich and a Cr-rich zone formed at the very top,followed by(ii)a fine-grained transition zone with incomplete oxidation and(iii)a non-oxidized zone with a porous *** varying elemental composition of these zones is furthermore accompanied by micro-structural variations and a complex residual stress development revealed by cross-sectional X-ray *** results provide a deeper understanding of the oxidation behavior of AlCr(Si)N coatings depending on their Si-content and the associated elemental,microstructural and residual stress evolution during high-temperature oxidation.

关键词： AlCrSiN Nanocomposite Cathodic arc Oxidation behaviour Cross-sectional X-ray nanodiffraction

Spontaneous liver rupture following SARS-CoV-2 infection in late pregnancy:A case report

在线全文

学校读者我要写书评

暂无评论

World Journal of Clinical Cases 2022年第15期10卷 5042-5050页

作者： Radek Ambroz Martin Stasek Ján Molnár Petr Spicka Dusan Klos jozef Hambálek Daniela Skanderová Department of Surgery I University Hospital Olomouc and Faculty of Medicine and DentistryPalacky UniversityOlomouc 77900Czech Republic Department of Obstetrics and Gynecology University Hospital Olomouc and Faculty of Medicine and DentistryPalacky UniversityOlomouc 77900Czech Republic Department of Pathology University Hospital Olomouc and Faculty of Medicine and DentistryPalackýUniversityOlomouc 77900Czech Republic

BACKGROUND Coronavirus disease-2019(COVID-19)caused by severe acute respiratory syndrome coronavirus 2(SARS-CoV-2)is characterized by systemic inflammatory response syndrome and ***-CoV-2 associated mortality ranges from 2%to 6%.Liver dysfunction was observed in 14%-53%of COVID-19 cases,especially in moderate severe ***,no cases of spontaneous hepatic rupture in pregnant women with SARS-CoV-2 have been *** SUMMARY A 32-year-old pregnant patient(gestational age:32 wk+4 d)without any remarkable medical history or long-term medication presented with ***,non-infectious,and pregnancy-related hepatopathies were *** onset of right subcostal pain with D-dimer and liver enzyme elevation was followed by shock with *** performing an emergency cesarean section,hemoperitoneum was observed,and the patient delivered a stillbirth.A 6-cm liver rupture at the edges of segments V and VI had occurred,which was sutured and ***-CoV-2 positivity on reverse transcriptionpolymerase chain reaction was *** revisions for intrahepatic hematoma with hemorrhagic shock and abdominal compartment syndrome were ***,the patient developed hemoptysis,which was treated using bronchoscopic therapy and non-invasive *** tissue biopsy revealed hemorrhagic foci and necrosis with an irregular centrilobular *** syndrome and autoimmune hepatitis were also ruled *** death was caused by acute intrauterine *** This case reveals that pregnant women with SARS-CoV-2 infection may be predisposed to liver parenchyma disease with liver rupture.

关键词： Liver rupture SARS-CoV-2 Pregnancy Abortion HELLP Case report

Corrosion Resistance of AZ91 Magnesium Alloy after Laser Remelting Treatment

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Wuhan University of Technology(Materials Science) 2016年第5期31卷 1075-1080页

作者： STRZELECKA Monika IWASZKO jozef MALIK Marcin A Czestochowa University of Technology 42-200 Czestochowa Poland

The main objective of the study was the modification of the surface layer of magnesium alloy by the COlaser. The studied material was the commercial AZ91 magnesium alloy. The effectiveness of the alternations caused by the remelting process was verified on the basis of microscopic observation and corrosion investigations, i e, recording of potentiodynamic polarization curves, electrochemical noise measurements and hydrogen evolution rate measurements. For the adopted range of the treatment parameters, favourable changes were observed in the surface layer such as the refinement of structure and more uniform arrangement of individual phases. As a consequence of those favourable structural changes the improvement of the corrosion resistance of the alloy was achieved in comparison to its non-remelted equivalent. For the treated material corrosion rates expressed as corrosion current densities were at least three times lower than the appropriate values for the untreated alloy comparing them for the same period of samples immersion in the test solution. The obtained results have confirmed the effectiveness of the applied surface treatment resulting in favourable changes in the structure and corrosion properties of the AZ91 magnesium alloy.

关键词： magnesium alloy CO_2 laser surface layer modification corrosion