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Impact-disrupted gunshot residue：A sub-micron analysis using a novel collection protocol

Defence Technology（防务技术） 2017年第3期13卷 143-149页

作者： v.Spathis School of Physical Sciences University of Kent

The analysis of gunshot residue(GSR) has played an integral role within the legal system in relation to shooting cases. With a characteristic elemental composition of lead, antimony, barium, and a typically discriminative spheroidal morphology, the presence and distribution of GSR can aid in firearm investigations. In this experiment, three shots of low velocity rim-fire ammunition were fired over polished silicon collection substrates placed at six intervals over a 100 cm range. The samples were analysed using a Field Emission Gun Scanning Electron Microscope(FEG-SEM) in conjunction with an X-flash Energy Dispersive X-ray(EDX) detector, allowing for GSR particle analyses of composition and structure at the sub-micron level. The results of this experiment indicate that although classic spheroidal particles are present consistently throughout the entire range of samples their sizes vary significantly, and at certain distances from the firearm particles with an irregular morphology were discerned, forming "impactdisrupted" GSR particles, henceforth colloquially referred to as "splats". Upon further analysis, trends with regards to the formation of these splat particles were distinguished. An increase in splat frequency was observed starting at 10 cm from the firearm, with 147 mm^(-2) splat density, reaching a maximal flux at 40 cm(451 mm^(-2)), followed by a gradual decrease to the maximum range sampled. Moreover, the structural morphology of the splats changes throughout the sampling range. At the distances closest to the firearm, molten-looking particles were formed, demonstrating the metallic residues were in a liquid state when their flight path was disrupted. However, at increased distances-primarily where the discharge plume was at maximum dispersion and moving away from the firearm, the residues have had time to cool in-fight resulting in semi-congealed and solid particles that subsequently disrupted upon impact, forming more structured as well as disaggregated

关键词：亚微米级残留物收集球形颗粒结构形态协议撞击元素组成

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Lorentz Generators for the Maxwell Field and Gauge Fixing

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Communications in Theoretical Physics 2019年第4期71卷 403-409页

作者： v.Debierre Max Planck Institue for Nuclear Physics

We propose a direct derivation of the Lorentz generators for the four-potential of electrodynamics on the basis of Wigner's theorem. The derivation relies on a study of the behaviour of polarisation vectors under k-space differentiation. The Coulomb and Lorenz gauges are discussed in that respect, and gauge invariance under Poincare′transformations is examined. The Poincar′e generators given by Bia lynicki-Birula and Bia lynicka-Birula are found to correspond to the Coulomb gauge case.

关键词： vector potential Lorentz generators polarisation vectors gauge condition

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Dolomitization of the lower cretaceous carbonate reservoir in the Euphrates Graben,Syria

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Petroleum Science 2021年第5期18卷 1342-1356页

作者： Yousef Ibrahem v.P.Morozov v.Sudakov Institute of Geology and Petroleum Technologies Kazan Federal UniversityKazan420008Russian Federation

Results of this study are based on core materials description,thin sections,Cathodoluminescence(CL),and Scanning Electron Microscope(SEM)*** Lower Cretaceous over the Euphrates Graben area was characterized by carbonate sedimentation in shallow marine *** low energy lagoonal to inner shelf sediments of the Judea Formation includes micritic mudstone to wackestone texture,dolomitic limestones and *** types of dolomites recognized in the carbonates of the Judea Formation,the preserving microcrystalline dolomites which commonly founded in the partially dolomitized micritic limestones,and the destructive coarsely crystalline dolomites which commonly founded in the dolostones and dolomitic *** examinations indicate that the preserving microcrystalline dolomites represent subtidal cycles developed in a shoal to open marine depositional environments,they probably formed under conditions of the shallow burial *** destructive coarsely crystalline dolomites may develop in more basinward,open marine environments under conditions of the deep burial diagenesis that accompanied by rising in temperature,pressure,and burial *** is believed that evolution of the diagenetic history of the Judean Formation sediments occurred in two diagenetic stages;the shallow burial diagenesis,and the deep burial *** processes,early fracturing,micritization,early calcite,and the early phase of dolomitization were part of the multiple diagenetic alterations during the shallow burial *** deep burial diagenesis was marked by dissolution,late stage of dolomitization and replacement,mechanical and chemical compaction,and the late calcite *** is believed that dolomitization of the Judea Formation carbonates in the Euphrates Graben has contributed to improving the reservoir properties by increasing the porosity and thus the permeability.

关键词： Dolomitization Carbonate Diagenesis Burial history Euphrates graben Syria

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Influence of Pt/Pd state on ceria-based support in CO oxidation

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Journal of Rare Earths 2023年第12期41卷 1963-1968,I0005页

作者： Igor v.Zagaynov Elena Yu.Liberman Alexander v.Naumkin A.A.Baikov Institute of Metallurgy and Materials Science MoscowRussia D.I.Mendeleev University of Chemical Technology of Russia MoscowRussia A.N.Nesmeyanov Institute of Organoelement Compounds MoscowRussia

Noble metal(M:Pt,Pd,PtPd) supported on ceria system catalysts were *** oxidized and reduced forms of the active component were examined in CO *** catalysts become more active after a reduction pretreatment,which shifts the temperature of CO *** of the data obtained from characterization techniques indicates that the strong interaction of metal ions with the support prevent the reduction of the initial MO_(x)to metallic *** formation of M-ceria interfaces efficiently boosts the oxygen activation during CO oxidation,leading to the formation of chemisorbed O on M and the regeneration of the ceria lattice oxygen,thus greatly improving the catalytic performance.

关键词： Ceria Platinum Palladium CO oxidation Rare earths

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Hot spots of DNA double-strand breaks and genomic contacts of human rDNA units are involved in epigenetic regulation

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Journal of Molecular Cell Biology 2015年第4期7卷 366-382页

作者： Nickolai A.Tchurikov Daria M.Fedoseeva Dmitri v.Sosin Anastasia v.Snezhkina Nataliya v.Melnikova Anna v.Kudryavtseva Yuri v.Kravatsky Olga v.Kretova Department of Epigenetic Mechanisms of Gene Expression Regulation Engelhardt Institute of Molecular BiologyMoscow 119334Russia Group of Postgenomic Studies Engelhardt Institute of Molecular BiologyMoscow 119334Russia Laboratory of DNA-Protein Interactions Engelhardt Institute of Molecular BiologyMoscow 119334Russia

DNA double-strand breaks(DSBs)are involved in many cellular mechanisms,including replication,transcription,and genome *** recent observation that hot spots of DSBs in human chromosomes delimit DNA domains that possess coordinately expressed genes suggests a strong relationship between the organization of transcription patterns and hot spots of *** this study,we performed mapping of hot spots of DSBs in a human 43-kb ribosomal DNA(rDNA)repeated *** observed that rDNA units corresponded to the most fragile sites in human chromosomes and that these units possessed at least nine specific regions containing clusters of extremely frequently occurring DSBs,which were located exclusively in non-coding intergenic spacer(IGS)*** hot spots of DSBs corresponded to only a specific subset of DNase-hypersensitive sites,and coincided with CTCF,PARP1,and HNRNPA2B1 binding sites,and H3K4me3 *** rDNA-4C data indicate that the regions of IGS containing the hot spots of DSBs often form contacts with specific regions in different chromosomes,including the pericentromeric regions,as well as regions that are characterized by H3K27ac and H3K4me3 marks,CTCF binding sites,ChIA-PET and RIP signals,and high levels of *** data suggest a strong link between chromosome breakage and several different mechanisms of epigenetic regulation of gene expression.

关键词： double-strand breaks fragile sites rDNA IGS PARP1 HNRNPA2B1 4C

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Anode Plasma Electrolytic Saturation of Titanium Alloys with Nitrogen and Oxygen

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Journal of Materials Science & Technology 2016年第10期32卷 1027-1032页

作者： P.N.Belkin S.A.Kusmanov A.v.Zhirov v.S.Belkin v.I.Parfenyuk Nekrasov Kostroma State University 1 May14Kostroma 156961Russia

In this work, we investigated the features of the anode plasma electrolytic saturation of titanium alloys with nitrogen and oxygen. In this case, the titanium samples may be heated to 1050 ℃ using aqueous solutions of ammonium chloride as working electrolyte. The weight of titanium samples is found to change due to their oxidation and anode dissolution. An X-ray diffractometer, a scanning electron microscope,nuclear proton backscattering and an optical microscope were used to characterize the phase and elemental composition of the modified layer. The electrolyte composition（10 wt% ammonium chloride, 5wt% ammonia） and processing mode（850 ℃, 5 min） of commercially pure titanium（CP-Ti） allowing to obtain the hardened surface layer up to 0.1 mm with microhardness of 220 Hv were proposed. Surface roughness Ra of samples after their nitriding for 5 min at 800 ℃ decreases from 1.67 to 0.082 μm. The anode plasma electrolytic nitriding could decrease friction coefficient and increase wear resistance of the CP-Ti. It is found that the anodic nitriding of low alloy titanium alloys reduces their corrosion rate in an aqueous solution of sulphuric（4.5%） and salt（0.2%） acids by 2 orders of magnitude. Results of cyclic testing show that anodic nitriding of commercial titanium leads to a decrease in corrosion rate by 8 times in solution of hydrochloric acid（6%） with addition of protein and vitamin.

关键词： Plasma electrolysis Titanium Nitriding Wear Corrosion

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vibration characteristics of piezoelectric functionally graded carbon nanotube-reinforced composite doubly-curved shells

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Applied Mathematics and Mechanics(English Edition) 2021年第6期42卷 819-840页

作者： v.v.THAM H.Q.TRANT T.M.TU National Univensity of Ciwil Engineering Giai Phong Road 55Hai Ba Trung DistrictHanoi 100000 Vietnam

This paper presents an analytical solution for the free vibration behavior of functionally graded carbon nanotube-reinforced composite(FG-CNTRC) doubly curved shallow shells with integrated piezoelectric layers. Here, the linear distribution of electric potential across the thickness of the piezoelectric layer and five different types of carbon nanotube(CNT) distributions through the thickness direction are considered. Based on the four-variable shear deformation refined shell theory, governing equations are obtained by applying Hamilton's principle. Navier's solution for the shell panels with the simply supported boundary condition at all four edges is derived. Several numerical examples validate the accuracy of the presented solution. New parametric studies regarding the effects of different material properties, shell geometric parameters, and electrical boundary conditions on the free vibration responses of the hybrid panels are investigated and discussed in detail.

关键词： free vibration four-variable shear deformation refined theory functionally graded carbon nanotube-reinforced composite(FG-CNTRC) piezoelectric material

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Second-Harmonic Response in Magnetic Nodal-Line Semimetal Fe_(3)GeTe_(2)

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Chinese Physics Letters 2022年第9期39卷 62-66页

作者： v.D.Esin A.A.Avakyants A.v.Timonina N.N.Kolesnikov E.v.Deviatov Institute of Solid State Physics of the Russian Academy of Sciences ChernogolovkaMoscow District2 Academician Ossipyan Str.142432Russia

We experimentally investigate second-harmonic transverse voltage response to ac electrical current for a magnetic nodal-line semimetal Fe_(3)GeTe_(2)(FGT).For zero magnetic field,the observed second-harmonic voltage behaves as a square of the longitudinal current,as it should be expected for nonlinear Hall *** magnetic field behavior is found to be sophisticated:while the first-harmonic response shows the known anomalous Hall hysteresis in FGT,the second-harmonic Hall voltage is characterized by the pronounced high-field hysteresis and flat(B-independent)region with curves touching at low *** high-field hysteresis strongly depends on the magnetic field sweep rate,so it reflects some slow relaxation *** the lowest rates,it is also accomplished by multiple crossing *** shape of the second-harmonic hysteresis is known for skyrmion spin textures in nonlinear *** skyrmions have been demonstrated for FGT by direct visualization techniques,we can connect the observed high-field relaxation with deformation of the skyrmion ***,the second-harmonic Hall voltage response can be regarded as a tool to detect spin textures in transport experiments.

关键词： harmonic relaxation hysteresis

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Biochemical Factors Affecting the Quality of Products and the Technology of Processing Deep-Sea Fish, the Giant Grenadier Albatrossia pectoralis

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Journal of Ocean University of China 2020年第3期19卷 681-690页

作者： PIvNENKO T.N. KARPENKO Yu.v. KRASHCHENKO v.v. POZDNYAKOvA Yu.M. ESIPENKO R.v. Far Eastern State Technical Fisheries University Vladivostok 690087Russia

The composition of muscle tissues of a deep-sea species, the giant grenadier(Albatrossia pectoralis), and a mesopelagic species, the Alaska pollock(Theragra chalcogramma), are compared. Grenadier is proved to have a higher moisture content(91.7%) and lower protein(7.4%) and lipid(0.3%) contents. The factors responsible for the softening and moisture separation during processing of grenadier are identified. Contents of some fractions of non-protein nitrogenous components, including trimethylamine oxide(TMAO) and free amino acids, are clarified. The proportion of the main myofibrillar proteins myosin and actin, which is considered as an indicator of efficiency of structure formation in fish muscle tissue during processing, is almost 20% lower in giant grenadier than in pollock. The effects of endogenous protease, Са^2+-ATPase and transglutaminase on the processes of autolysis, denaturation, and possibility of myofibrillar proteins cross-linking were also studied. The proposed technology of getting a nutritionally balanced, gel-like, ready-to-use foodstuff from grenadier fillet includes its enrichment with pollock muscle tissue and supplementing with a binary structure-forming agent containing collagen and chitosan. Nutritional value of the products is assessed by the method of biological assay and by determining the denaturation changes of myofibrillar proteins. The modes of fine mincing and thermal processing, as well as the shelf-life of the finished product are justified. The developed technology of producing a ready-to-eat food from giant grenadier will allow a more efficient use of this underutilized resource.

关键词： giant grenadier Alaska pollock myosin actin proteases ATPase transglutaminase softening structure formation ready-to-eat foodstuffs

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A novel multi-scale μCT characterization method to quantify biogenic carbonate production

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Geoscience Frontiers 2024年第6期15卷 43-56页

作者： v.Chandra R.Sicat F.Benzoni v.vahrenkamp v.Bracchi Physical Sciences and Engineering King Abdullah University of Science and TechnologyThuwalSaudi Arabia visualization Core Lab King Abdullah University of Science and TechnologyThuwalSaudi Arabia Biological and Environmental Science and Engineering King Abdullah University of Science and TechnologyThuwalSaudi Arabia Department of Earth and Environmental Sciences University of Milano-BicoccaMilanItaly Saudi Aramco DhahranSaudi Arabia

Biogenic carbonate structures such as rhodoliths and foraminiferal-algal nodules are a significant part of marine carbonate production and are being increasingly used as paleoenvironmental indicators for predictive modeling of the global carbon cycle and ocean acidification ***,traditional methods to characterize and quantify the carbonate production of biogenic nodules are typically limited to two-dimensional analysis using optical and electron *** micro-computed tomography(lCT)is an excellent tool for 3D analysis of inner structures of geomaterials,the trade-off between sample size and image resolution is often a limiting *** this study,we address these challenges by using a novel multi-scale lCT image analysis methodology combined with electron microscopy,to visualize and quantify the carbonate volumes in a biogenic calcareous *** applied our methodology to a foraminiferal-algal nodule collected from the Red Sea along the coast of NEOM,Saudi *** lCT and SEM image analyses revealed the main biogenic carbonate components of this nodule to be encrusting foraminifera(EF)and crustose coralline algae(CCA).We developed a multi-scale lCT analysis approach for this study,involving a hybrid thresholding and machine-learning based image *** utilized a high resolution lCT scan from the sample as a ground-truth to improve the segmentation of the lower resolution full volume lCT scan which provided reliable volumetric quantification of the EF and CCA ***,the EF and CCA layers contribute to approximately 65.5%of the studied FAN volume,corresponding to 69.01 cm3 and 73.32 cm3 respectively,and the rest is comprised of sediment infill,voids and other minor ***,volumetric quantification results in conjunction with CT density values,indicate that the CCA layers are associated with the highest amount of carbonate production within this foraminiferal-algal *** methodology developed for t

关键词： Crustose coralline algae Foraminifera μCT Image analysis Machine learning Marine carbonate factory

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