Artykuły w czasopismach: „Nonmetallic crystals”

1

Vinetskii, V. L., �. A. Pashitskii i V. A. Yanchuk. "Bipolarons in nonmetallic crystals". Journal of Structural Chemistry 27, nr 6 (1987): 1004–8. http://dx.doi.org/10.1007/bf00755217.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

2

Hirao, Kiyoshi, Koji Watari, Hiroyuki Hayashi i Mikito Kitayama. "High Thermal Conductivity Silicon Nitride Ceramic". MRS Bulletin 26, nr 6 (czerwiec 2001): 451–55. http://dx.doi.org/10.1557/mrs2001.115.

Pełny tekst źródła

Streszczenie:

Since the confirmation that nonmetallic single crystals with a diamond-like structure, such as SiC, BP, and AlN, have high intrinsic thermal conductivities of over 300 W m−1 K−1,1,2 a great deal of effort has been focused on the development of nonoxide polycrystalline ceramics with high thermal conductivity.

Style APA, Harvard, Vancouver, ISO itp.

3

Kovarskii, V. A. "High-order optical-harmonic generation in films of nonmetallic crystals". Journal of Experimental and Theoretical Physics 85, nr 1 (lipiec 1997): 48–51. http://dx.doi.org/10.1134/1.558314.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

4

Pereira, A. S., i J. A. H. da Jornada. "Environment and time dependent hardness in zirconia". Journal of Materials Research 9, nr 5 (maj 1994): 1059–62. http://dx.doi.org/10.1557/jmr.1994.1059.

Pełny tekst źródła

Streszczenie:

The microhardness of monoclinic ZrO2 single-crystals was measured in different environments: air, water, and toluene. An indentation creep process at room temperature was observed for the measurements in moist media pointing for a water-activated plastic relaxation mechanism. This effect is discussed employing the models previously proposed to explain similar behaviors in ZrO2 and other nonmetallic materials. A possible correlation with the conditions for the nucleation in phase transitions is proposed.

Style APA, Harvard, Vancouver, ISO itp.

5

Howe, J. M., i S. J. Rozeveld. "Effect of crystal and beam tilt on simulated high-resolution TEM images of interfaces". Proceedings, annual meeting, Electron Microscopy Society of America 48, nr 4 (sierpień 1990): 358–59. http://dx.doi.org/10.1017/s0424820100174928.

Pełny tekst źródła

Streszczenie:

It is well known that only a few milliradians of crystal or beam tilt can produce image artifacts in HRTEM images of perfect crystals. One important application of HRTEM is for determining the atomic structures of interfaces. While it is intuitive that alignment of an interface parallel to the electron beam should be critical for obtaining reliable HRTEM images of interfaces, a systematic study of the effects of crystal and beam tilt on HRTEM images of interfaces has not been performed.In this investigation, the effects of crystal and beam tilt on HRTEM images of planar, coherent interfaces were determined by multislice image simulations. Interfaces in metallic systems ranging from simple twin boundaries in f.c.c. Al and b.c.c. Ti to relatively complex interphase boundaries between ordered h.c.p. and b.c.c. phases in the Ti-Al system were examined and compared. Although this study was limited to coherent interfaces, similar effects are expected to occur in comparable nonmetallic systems such as semiconductors and ceramics and for less coherent interfaces as well.

Style APA, Harvard, Vancouver, ISO itp.

6

Kolontsova, E. V., A. E. Korneev, I. S. Pogosova i S. V. Reďko. "On the criterion and mechanism of radiation-induced structure changes in nonmetallic crystals". Radiation Effects 100, nr 1-2 (grudzień 1986): 31–38. http://dx.doi.org/10.1080/00337578608208733.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

7

Volcheck, V. S., M. S. Baranava i V. R. Stempitsky. "Thermal conductivity of wurtzite gallium nitride". Proceedings of the National Academy of Sciences of Belarus, Physical-Technical Series 67, nr 3 (8.10.2022): 285–97. http://dx.doi.org/10.29235/1561-8358-2022-67-3-285-297.

Pełny tekst źródła

Streszczenie:

This paper reviews the theoretical and experimental works concerning one of the most important parameters of wurtzite gallium nitride – thermal conductivity. Since the heat in gallium nitride is transported almost exclusively by phonons, its thermal conductivity has a temperature behavior typical of most nonmetallic crystals: the thermal conductivity increases proportionally to the third power of temperature at lower temperatures, reaches its maximum at approximately 1/20 of the Debye temperature and decreases proportionally to temperature at higher temperatures. It is shown that the thermal conductivity of gallium nitride (depending on fabrication process, crystallographic direction, concentration of impurity and other defects, isotopical purity) varies significantly, emphasizing the importance of determining this parameter for the samples that closely resemble those being used in specific applications. For isotopically pure undoped wurtzite gallium nitride, the thermal conductivity at room temperature has been estimated as high as 5.4 W/(cm·K). The maximum room temperature value measured for bulkshaped samples of single crystal gallium nitride has been 2.79 W/(cm·K).

Style APA, Harvard, Vancouver, ISO itp.

8

Ma, Yanbao. "A transient ballistic–diffusive heat conduction model for heat pulse propagation in nonmetallic crystals". International Journal of Heat and Mass Transfer 66 (listopad 2013): 592–602. http://dx.doi.org/10.1016/j.ijheatmasstransfer.2013.06.069.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

9

Kootstra, F., P. L. de Boeij i J. G. Snijders. "Application of time-dependent density-functional theory to the dielectric function of various nonmetallic crystals". Physical Review B 62, nr 11 (15.09.2000): 7071–83. http://dx.doi.org/10.1103/physrevb.62.7071.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

10

Murlieva, Zh Kh. "Linear Dependence of the Phonon Thermal Resistance of Nonmetallic Crystals on the Isobaric Thermal Strain". Physics of the Solid State 45, nr 12 (2003): 2276. http://dx.doi.org/10.1134/1.1635497.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

11

Kootstra, F., P. L. de Boeij i J. G. Snijders. "Efficient real-space approach to time-dependent density functional theory for the dielectric response of nonmetallic crystals". Journal of Chemical Physics 112, nr 15 (15.04.2000): 6517–31. http://dx.doi.org/10.1063/1.481315.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

12

Ruan, Jujun, Jiaxin Huang, Zhihui Yuan i Rongliang Qiu. "Elements in the Crystals Determine the Distribution of Bromine in Nonmetallic Particles of Crushed Waste Printed Circuit Boards". ACS Sustainable Chemistry & Engineering 6, nr 11 (16.10.2018): 13650–55. http://dx.doi.org/10.1021/acssuschemeng.8b03884.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

13

Kinoshita, Chiken, Hiroaki Abe, Ken-ichi Fukumoto, Kiyomichi Nakai i Kazutoshi Shinohara. "Accumulation and annihilation processes of cascades in metallic and nonmetallic crystals under irradiation with ions and/or electrons". Ultramicroscopy 39, nr 1-4 (listopad 1991): 205–12. http://dx.doi.org/10.1016/0304-3991(91)90199-g.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

14

Стародуб, Ольга Ростиславна, Вячеслав Михайлович Воскресенский, Николай Васильевич Сидоров i Михаил Николаевич Палатников. "COMPARATIVE ANALYSIS OF THE INFLUENCE OF DOPING IONS OF YTTRIUM AND BORON FORMATION OF DEFECTS IN LITHIUM NIOBATE CRYSTALS". Physical and Chemical Aspects of the Study of Clusters, Nanostructures and Nanomaterials, nr 13 (23.12.2021): 411–20. http://dx.doi.org/10.26456/pcascnn/2021.13.411.

Pełny tekst źródła

Streszczenie:

Кристалл ниобата лития, являющийся широко используемым и весьма востребованным в настоящее время нелинейно-оптическим материалом, примечателен своей способностью к варьирования широкого спектра сегнетоэлектрических и нелинейно-оптических характеристик в зависимости от типа и концентрации примесного иона, а также от соотношения Li / Nb . На основе разработанного нами подхода к моделированию кластеров в кристалле ниобата лития, в котором рост кластера идёт не элементарными ячейками, а кислородными октаэдрами, проведён сравнительный анализ особенностей внедрения в кристалл примесных ионов иттрия и бора с одинаковым зарядом +3 . Показано, что встраивание, вследствие различного ионного радиуса, идёт по двум механизмам: если для металла иттрия действует обычный механизм, когда примесной ион локализуется внутри кислородного октаэдра, то ион неметаллического элемента бора встраивается в тетраэдрические пустоты структуры, а именно в кислородные плоскости, образующие октаэдр. При этом влияние данных примесных ионов на одну из важнейших характеристик ниобата лития оказывается диаметрально противоположным: иттрий усиливает фоторефрактивный эффект, бор -понижает, что необходимо учитывать при направлении целевого использования кристаллов ниобата лития. Lithium niobate crystals, which are a widely used and highly demanded as nonlinear optical material, are remarkable for their ability to vary a wide range of ferroelectric and nonlinear optical characteristics depending on the type and concentration of the impurity ion, as well as on the Li / Nb ratio. Based on our approach to modeling clusters in the lithium niobate crystal, in which the cluster grows not by unit cells, but by oxygen octahedra, we have carried out a comparative analysis of the features of the incorporation of impurity ions of yttrium and boron with the same charge +3 into the crystal. It is shown that due to the different ionic radii the incorporation proceeds by to two mechanisms. If for yttrium the usual mechanism operates, when the impurity ion is localized inside the oxygen octahedron. The ion of boron, i.e. a nonmetallic element, is incorporated into the tetrahedral voids of the structure, namely, into the oxygen planes forming the octahedron. In this case, the influence of these impurity ions on one of the most important characteristics of lithium niobate turns out to be diametrically opposite: yttrium enhances the photorefractive effect, boron decreases it, which must be taken into account in the direction of targeted use of lithium niobate crystals.

Style APA, Harvard, Vancouver, ISO itp.

15

Zhakupova, A. T., i V. A. Salina. "Comparative analysis of the structure of solid and hollow steel cast billets". Kompleksnoe Ispolʹzovanie Mineralʹnogo syrʹâ/Complex Use of Mineral Resources/Mineraldik Shikisattardy Keshendi Paidalanu 317, nr 2 (15.06.2021): 23–29. http://dx.doi.org/10.31643/2021/6445.14.

Pełny tekst źródła

Streszczenie:

This paper presents the research results of solid structure and hollow steel billets obtained by continuous casting. To substantiate the feasibility of using a hollow billet as an initial one in the production of seamless hot-rolled pipes, a comparative analysis of the distribution of non-metallic inclusions, macro- and microstructure, as well as segregation by structural zones was carried out. When analyzing the macrostructure of a hollow billet, two distinct zones were revealed: equiaxed small and columnar crystals, which distinguishes it, compared with a solid billet, by the absence of a zone of misoriented crystals. This, in turn, helps to eliminate defects such as axial porosity and segregation. The improved quality of the macrostructure during casting of a hollow billet is explained by more favourable conditions for heat removal and a higher rate of solid-phase advance due to bilateral cooling, and less shrinkage of the melt due to its cross-sectional geometry. The distribution of nonmetallic inclusions, consisting of oxide, sulfide and oxysulfide compounds, and liquidation elements, showed that they are concentrated mainly at the boundaries of crystalline zones, and for a solid billet and in the central part. This fact is caused by the development of a zone of intense heat removal. When research the microstructures of solid and hollow workpieces, a ferrite-pearlite mixture is observed in both cases. The microstructure of the hollow billet is more dispersed, which is confirmed by durometric measurements.

Style APA, Harvard, Vancouver, ISO itp.

16

Yamada, Tomonori, Ryan P. Brewster i So Hirata. "Asymptotic expansion of two-electron integrals and its application to Coulomb and exchange lattice sums in metallic, semimetallic, and nonmetallic crystals". Journal of Chemical Physics 139, nr 18 (14.11.2013): 184107. http://dx.doi.org/10.1063/1.4828796.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

17

Simachev, A. S., T. N. Oskolkova, A. A. Umanskii i A. V. Golovatenko. "Non-metallic inclusions in different zones of crystallization of E90KhAF rail steel". Izvestiya. Ferrous Metallurgy 64, nr 2 (2.04.2021): 135–42. http://dx.doi.org/10.17073/0368-0797-2021-2-135-142.

Pełny tekst źródła

Streszczenie:

Metallographic and X-ray studies of continuously cast billets of E90KhAF rail steel have been carried out. We have established the regularities of non-metallic inclusions distribution over the crystallization zones before and after billets deformation. It was revealed that in crustal zone the main non-metallic inclusions are point oxides, aluminum nitrides, iron silicates (FeO·SiO2) and alumosilicates (Al2O3·SiO2). They were identified in the zone of columnar crystals. In central zone of the billet, manganese sulfides (MnS), manganese silicates (MnO·SiO2), alumosilicates (Al2O3·SiO2), iron silicates (FeO·SiO2), and point oxides were found. It has been determined that concentration and size of nonmetallic inclusions tend to increase from the surface to central zone of continuously cast billets, which is consistent with generally accepted ideas about mechanisms of billet formation during crystallization. The mechanism of deformation of two-phase silicate non-metallic inclusions and their influence on quality of rail products was disclosed. It is shown that inhomogeneous deformability of complex silicate inclusions aggravates their harmful effect on rail products quality. In this case, additional stresses appear in addition to inclusion-matrix deformation and contact stresses existing at interphase boundaries. This pattern also holds for non-deformed silicate inclusions. Such a distribution of inclusions in the billets volume somewhat reduces their negative effect on rails quality, since near-contact layers of the billet undergo more intense deformation during rolling, and as the axial zone of a billet is approached, deformation rate decreases.

Style APA, Harvard, Vancouver, ISO itp.

18

Briant, C. L. "Grain Boundary Chemistry and Reactions in Metals". MRS Bulletin 15, nr 10 (październik 1990): 26–32. http://dx.doi.org/10.1557/s0883769400058632.

Pełny tekst źródła

Streszczenie:

An interface can be defined as a surface that serves as a common boundary between two phases. Examples include the boundaries between two solids, two immiscible liquids, a solid and a liquid, a solid and a gas, and a liquid and a gas. Interfaces have been studied for decades by scientists of many different disciplines. One reason for this interest is that the atomic structure and the chemical composition at the interface can differ from that of the bulk material on either side of it. Consequently, the properties of the interface can differ greatly from those of either bulk phase, and chemical reactions can occur more readily at the interface than in the bulk.All the interfaces listed in the previous paragraph are of interest to materials scientists. However, this article will only consider the grain boundary because it has received the most attention by researchers in materials science. Furthermore, we will only consider grain boundaries in metals; nonmetallic systems will be covered in other articles in this issue.A grain boundary is an interface that exists where two single crystals are joined in such a way that their crystallographic orientations are not completely matched. Thus, any polycrystalline material contains many grain boundaries. They occur wherever the individual grains meet one another and can usually be observed by etching a polished cross section of the surface as shown in Figure 1. Grain boundaries first form in a metal as a result of the multiple nucleation sites that occur during solidification.

Style APA, Harvard, Vancouver, ISO itp.

19

Teplyakova, S. N., i C. A. Lorenz. "Crystallisation of the metal in iie irons and possible meteorite analog". Геохимия 64, nr 8 (3.09.2019): 826–36. http://dx.doi.org/10.31857/s0016-7525648826-836.

Pełny tekst źródła

Streszczenie:

The metal of the IIE irons has evidence of fractionation in the depths of the asteroid, but the presence of a fine-grained structure is incompatible with its endogenous origin. It was assumed that the metal underwent remelting on the surface of the parent body. Data on the mineragraphy, mineral and chemical composition of IIE irons (Elga, Verkhnodniprovsk, Tobychan, Miles and Watson) indicate that the relatively fine-grained metal structure and xenomorphic schreibersite grains were probably formed by crystallization from the melt. According to the calculated data on the bulk composition of the Elga metal and on the Fe-Ni-P phase diagrams, the crystallization of the first γ-Fe grains began at ~1511°С and ended at ~1060–1100°С with the formation of polygonal crystals of cm-sized taenite and xenomorphic schreibersite along their boundaries. The identical composition of xenomorphic schreibersite, both along the borders of the taenite grains and on the rims around nonmetallic inclusions, indicates their simultaneous formation. Among four generations of schreibersite, the xenomorphic schreibersite is distinguished by a high Fe/Ni ratio. It is also noted that the higher the crystallization temperature of schreibersite, the less nickel content in this schreibersite. Similar metal structures were found in other types of meteorites: in the IAB irons and in metal of some mesosiderites, and the impact mechanism of formation is considered the most likely for them. Thus, the mechanism of formation of the IIE irons by shock remelting of fractionated metal and mixing with silicate fragments in the conditions of the parent surface may have analogues among other types of meteorites.

Style APA, Harvard, Vancouver, ISO itp.

20

Pustovoit, V. N., i Yu V. Dolgachev. "REVISITING THE NATURE OF SITES OF MARTENSITE NUCLEATION DURING STEEL HARDENING". Izvestiya. Ferrous Metallurgy 62, nr 2 (30.03.2019): 109–14. http://dx.doi.org/10.17073/0368-0797-2019-2-109-114.

Pełny tekst źródła

Streszczenie:

Presence of microvolumes most prepared for the martensite emergence in austenite is discussed. Aming many works dealing with martensitic transformations, rare works are devoted to the location of martensite origin. This aspect of transformation is important, since it allows us to obtain new knowledge about scenarios for γ → α transformation development during quenching of steel. The martensite embryos are submicron austenite volumes that are most prepared for phase transition and are characterized by increased energy. Experimental results were obtained by the methods of high-temperature metallography. Steel structure observed as a result of vacuum etching was studied, as well as the surface relief caused by shear during the martensitic transformation. The resulting structural patterns made it possible to observe most of the possible places for martensite emergence: nonmetallic inclusions, twins, high-angle and small-angle grain boundaries, previously formed martensite crystals, dislocations and elements of the disclination structure. It is shown that a high dislocation density is observed in the twin area, which facilitates nucleation of martensite as a result of disappearance of part of elastic energy of the dislocation when atoms inside the embryo are rearranged. When nucleation occurs on the grain boundaries, energy is released, which is used to construct a new interphase boundary and to compensate emerging elastic energy. The relative energy of the boundaries of different types was estimated by the method of multi-beam interferometry. The depth of the grooves that were formed on the surface by thermal etching was measured. Elements of disclination structure resulting from inhomogeneous deformation were observed, which are also sites of germinal centers formation. It is noted that nanoareas with ferromagnetic order, which are present in paramagnetic austenite, may not be observed with the help of the technique used in this work. However, magnetism plays a decisive role in realization of one or another scenario of the development of phase transformation in steels. Obtaining data on the interaction of ferromagnetic areas in austenite with each other, with crystal lattice defects, the magnetic field, and data on their lifetime, number and size is an important task for future research.

Style APA, Harvard, Vancouver, ISO itp.

21

Yamada, Tomonori, Ryan Brewster i So Hirata. "Erratum: “Asymptotic expansion of two-electron integrals and its application to Coulomb and exchange lattice sums in metallic, semimetallic, and nonmetallic crystals” [J. Chem. Phys. 139, 184107 (2013)]". Journal of Chemical Physics 140, nr 24 (28.06.2014): 249902. http://dx.doi.org/10.1063/1.4885655.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

22

Anisovich, A. G. "OPTICAL EFFECTS AT NONMETALLIC MATERIALS MICROSCOPY". Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), nr 1 (14.03.2017): 110–14. http://dx.doi.org/10.21122/1683-6065-2017-1-110-114.

Pełny tekst źródła

Streszczenie:

The optical effects which appeared on internal defects of optically transparent materials by use of various methods of optical staining, i. e. dark-field illumination and polarized light were researched. It was shown that methods of optical staining support to determine spherical defects under a surface of optically transparent materials. Formation of optical effects on materials defects in dark background are partially determined by design features of microscope objective and it was found out. It was defined that the investigation using polarized light the image formation of spherical defects occurs similar to uniaxial crystal.

Style APA, Harvard, Vancouver, ISO itp.

23

Roberts, Andrew C., T. Scott Ercit, Alan J. Criddle, Gary C. Jones, R. Scott Williams, Forrest F. Cureton i Martin C. Jensen. "Mcalpineite, Cu3TeO6·H2O, a new mineral from the McAlpine mine, Tuolumne County, California, and from the Centennial Eureka mine, Juab County, Utah". Mineralogical Magazine 58, nr 392 (wrzesień 1994): 417–24. http://dx.doi.org/10.1180/minmag.1994.058.392.07.

Pełny tekst źródła

Streszczenie:

AbstractMcalpineite, ideally Cu3TeO6·H2O, occurs as isolated 0.5 mm-sized emerald green cryptocrystalline crusts on white quartz at the long-abandoned McAlpine mine, Tuolumne County, California, U.S.A. Associated nonmetallic phases are muscovite (mariposite), calcite, goethite, hematite, chlorargyrite, choloalite, keystoneite, mimetite, malachite, azurite, annabergite and a host of unidentified crusts, both crystalline and amorphous. Associated metallic minerals include pyrite, acanthite, hessite, electrum, altaite, native silver, galena, pyrargyrite, sphalerite and owyheeite. The mineral has also been identified at the Centennial Eureka mine, Juab County, Utah, U.S.A., where it occurs as interstitial olive-green coatings and as millimetre-sized dark green-black cryptocrystalline nodules lining drusy quartz vugs. Associated minerals are xocomecatlite, hinsdalite-svanbergite, goethite and several new species including two hydrated copper tellurates, a hydrated copper-zinc tellurate/tellurite, and a hydrated copper-zinc tellurate/tellurite-arsenate-chloride. Mcalpineite is cubic, P-lattice (space group unknown), a = 9.555(2) Å, V = 872.4(4) Å. The strongest six lines in the X-ray powder-diffraction pattern [d in Å (I) (hkl)] are: 4.26(40)(210), 2.763(100)(222), 2.384(70)(400), 1.873(40)(431,510), 1.689(80)(440) and 1.440(60)(622). The average of four electron-microprobe analyses (McAlpine mine) is CuO 50.84, NiO 0.17, PbO 4.68, SiO2 0.65, TeO3 39.05, H2O (calc.) [4.51], total [100.00] wt. %. With O = 7, the empirical formula is (Cu2.79Pb0.09Ni0.01)∑2.89(Te0.97Si0.05)∑1.02O5.90·1.10H2O. This gives a calculated density of 6.65. g/cm3 for Z = 8. The average of two electron-microprobe analyses (Centennial Eureka mine) is CuO 51.2, ZnO 3.1, TeO3 39.0, SiO2 0.2, As2O5 0.8, H2O (by CHN elemental analyser) 7, total 101.3 wt. %, leading to the empirical formula (Cu2.56Zn0.15)∑2.71 (Te0.88Si0.02As0.02)∑0.92O5.47·1.53H2O. The infrared absorption spectrum shows definite bands for structural H2O with an O-H stretching frequency centred at 3320 cm−1 and a H-O-H flexing frequency centred at 1600 cm−1. In reflected light Mcalpineite is isotropic, nondescript grey, with ubiquitous brilliant apple to lime green internal reflections. The refractive index calculated from Fresnel equations is 2.01. Measured reflectance values in air and in oil are tabulated. Reflectance study also shows that cryptocrystalline aggregates are composed of micron-sized sheaves of fibrous or prismatic crystals. Other physical properties include: adamantine lustre; light green streak; brittle; uneven fracture; translucent to transparent and nonfluorescent under both long- and short-wave ultraviolet light. The name is for the first known locality, the McAlpine mine.

Style APA, Harvard, Vancouver, ISO itp.

24

Anisovich, A. G. "OPTICAL EFFECTS AT METALLIC AND NONMETALLIC MATERIALS MICROSCOPY". Litiyo i Metallurgiya (FOUNDRY PRODUCTION AND METALLURGY), nr 4 (4.01.2018): 119–25. http://dx.doi.org/10.21122/1683-6065-2017-4-119-125.

Pełny tekst źródła

Streszczenie:

Optical effects arising on surface defects of metals, alloys and transparent materials are discovered in conditions of various illumination such as dark-field and bright-field illumination as well as polarized light. It is shown that the methods of optical contrasting let it possible to determine surface defects of metallic and nonmetallic materials as well as defects inside optically transparent materials. The connection between optical effects and design features of lens by the use of dark-field illumination was shown. It is established that picture generation of spherical defect came about by analogy to uniaxial crystal by the study using polarized light. The schematic diagram of optical effects for various materials to make visual classification of surface defects is suggested.

Style APA, Harvard, Vancouver, ISO itp.

25

Kosenkov, V. M., i S. A. Vorob'ev. "Crystal-chemical aspect of the radiation resistance of nonmetallic materials". Atomic Energy 84, nr 1 (styczeń 1998): 23–27. http://dx.doi.org/10.1007/bf02430650.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

26

Li, Qiang, Yu Gu i Nanfei Wang. "Free Vibration Analysis of a New Polymer Quartz Piezoelectric Crystal Sensor Applied to Identify Chinese Liquors". International Journal of Applied Mechanics 09, nr 01 (styczeń 2017): 1750015. http://dx.doi.org/10.1142/s1758825117500156.

Pełny tekst źródła

Streszczenie:

This paper deals with the analytical and numerical analysis of free vibration in a new polymer piezoelectric crystal sensor. A quartz piezoelectric crystal here serves as the basal material and nonmetallic polymer thin films with perforative central holes as the surface coating according to the principle of quartz crystal microbalance (QCM), based on the Kirchhoff–Love plate model. A mechanical model of the new sensor was built, and its structure was a quartz piezoelectric sandwich composite circular plate with perforative central holes in the surface layers. The form of the electric potential field in the piezoelectric layer was here assumed to be such that the Maxwell static electricity equation is satisfied. The validation of the mechanical model and its analytic method is conducted by comparing the free vibration frequencies of the piezoelectric sandwich composite circular plate produced by the mechanical model’s analytical and numerical analyses performed using ANSYS software. Results show that the first 100 orders of free vibration frequency values of the mechanical model obtained by two methods, the analytical analysis and the numerical analysis, to be fit. The maximum absolute deviation rate ([Formula: see text] between the analytical solutions ([Formula: see text]) and the numerical solutions ([Formula: see text]) was found to be 6.89%. These results are important reference for the design of the new polymer quartz piezoelectric crystal sensors suitable for the identification of Chinese liquors.

Style APA, Harvard, Vancouver, ISO itp.

27

Wang, You, Farhan Mumtaz i Yutang Dai. "Micromachining of SiO₂ single crystal wafer using femtosecond laser". Journal of Laser Applications 35, nr 2 (maj 2023): 022004. http://dx.doi.org/10.2351/7.0000877.

Pełny tekst źródła

Streszczenie:

Silicon dioxide (SiO2), a new type of inorganic nonmetallic material, has been widely used in people's livelihood and military industry. For silicon dioxide-based applications, ultra-precision micromachining is a crucial component that impacts the performance of the finished products. This research reports the precise micromachining of silicon dioxide wafers by femtosecond laser. A prediction model for groove processing size is developed, and an experiment is carried out to investigate the silicon dioxide groove processing technology. The effects of processing parameters that include laser power, scanning speed, scanning repetitions, and defocus amount on the processed properties of grooves, the heat affected zone, and processed roughness are discussed. The variable defocus processing method is proposed, which can effectively improve the inclination angle of the groove wall and the quality of the machined groove. Moreover, scanning electron microscopy is used to analyze the groove morphology, allowing for the improvement of surface quality and processing parameter optimization.

Style APA, Harvard, Vancouver, ISO itp.

28

Du, Xiao Li, Lan Yu, Bin Zhang, Shi Jin Song i Guo Fang Li. "Effects of Cu Doping on the Microstructure and Electrical Properties of Sr₃YCo₄O_10.5_+δ Polycrystalline". Advanced Materials Research 934 (maj 2014): 80–85. http://dx.doi.org/10.4028/www.scientific.net/amr.934.80.

Pełny tekst źródła

Streszczenie:

Polycrystalline samples of Sr3YCo4-xCuxO10.5+δ (x=0, 0.2, 0.4, 0.6) have been prepared by solid state reaction method. Crystal structure has been checked by X-ray diffraction (XRD) and the results indicate that Sr3YCo4-xCuxO10.5+δ (x=0, 0.2, 0.4) with single phase have been synthesized in air, and the lattice parameters of Sr3YCo4-xCuxO10.5+δ (x=0, 0.2, 0.4) increase with increasing Cu content. Microstructure analysis demonstrates that the grain sizes enlarge and the number of pores decreases with increasing Cu content. The change of porous structure with different Cu contents is discussed by the liquid sintering theory. The temperature dependence of resistivity (ρ-T) curves of Sr3YCo4-xCuxO10.5+δ show nonmetallic behavior. And the electrical resistivity decreases successively with increasing Cu content, which is caused by the porous structure scattering the carriers as well as the increase of hole carriers.

Style APA, Harvard, Vancouver, ISO itp.

29

Kuraposhin, V. S., A. L. Talis, E. D. Demina i A. I. Zaitsev. "Crystal Geometry Mechanism of Intergrowth of Spinel and Manganese Sulfide into a Complex Nonmetallic Inclusion". Metal Science and Heat Treatment 57, nr 7-8 (listopad 2015): 371–78. http://dx.doi.org/10.1007/s11041-015-9892-4.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

30

Abatal, Mohamed. "Structural, electrical and magnetic properties of the pyrochlorate Er_2-x Sr_x Ru_2O_7 (0<=x<=0.10) system". Revista Mexicana de Física 64, nr 3 (30.04.2018): 222. http://dx.doi.org/10.31349/revmexfis.64.222.

Pełny tekst źródła

Streszczenie:

In this research, we report a detailed study of the structural, electrial and magnetic properties of the ruthenium pyrochlore with the composition (Er_2-x Sr_x) Ru_2O_7 0<=x<=0.10 prepared by solid-state reaction in air at ambient pressure. The synthesized products were characterized using powder X-ray diffraction. The structure of the samples was refined with the Rietveld method, showing that the lattice parameters are more sensitive to the Strontium and Erbium sites. Scanning electron microscopy shows that the crystal size varies between 0.27 and 0.62 mu m. In all polycrystalline samples, the electrical resistance decreases with increasing temperature, indicating that the samples are nonmetallic. The slope of the temperature-dependent resistance profiles systematically decreases with increasing x, proving that the carrier concentration increases with increasing the Sr content. Zero-field-cooled and field cooled magnetization measurements show an irreversible behavior where the split is systematically enhanced by increasing x.

Style APA, Harvard, Vancouver, ISO itp.

31

Kirchner, Martin, Walter Schnelle i Rainer Niewa. "Inverse Perovskites (RE3N)Sn with RE = La, Ce, Pr, Nd, Sm: Preparation, Crystal Structures and Physical Properties". Zeitschrift für Naturforschung B 61, nr 7 (1.07.2006): 813–19. http://dx.doi.org/10.1515/znb-2006-0707.

Pełny tekst źródła

Streszczenie:

The ternary compounds (RE3N)Sn with RE = La, Ce, Pr, Nd, Sm were prepared starting from the elements. The compounds with RE = La, Ce, Pr were obtained as single phase materials according to X-ray powder diffraction patterns, which also indicate the cubic inverse perovskite crystal structure (space group Pm3̄m, La: a = 509.48(2) pm, Ce: a = 501.59(2) pm, Pr: a = 497.53(2) pm, Nd: a = 494.70(5) pm, Sm: a =488.35(9) pm). Chemical analyses proof the correct composition and particularly the absence of nonmetallic constituents next to nitrogen. All studied compounds show metallic characteristics in the electrical resistivity. Magnetic susceptibility measurements indicate (La3N)Sn to be a Pauli-paramagnet. Initially observed superconductivity was traced down to be due to thin La films on the surface of the grains. The Ce and Pr containing compounds show the behavior of 4f1 ions and 4f2 ions, and order antiferromagnetically at 6.8(2) K and 48(1) K, respectively.

Style APA, Harvard, Vancouver, ISO itp.

32

Sohail, Muhammad, Muhammad Zeshan Ashraf, Raziya Nadeem, Shamsa Bibi, Rabia Rehman i Muhammad Adnan Iqbal. "Techniques in the synthesis of organometallic compounds of tungsten". Reviews in Inorganic Chemistry 40, nr 1 (26.03.2020): 1–45. http://dx.doi.org/10.1515/revic-2019-0013.

Pełny tekst źródła

Streszczenie:

AbstractTungsten is an elegant substance, and its compounds have great significance because of their extensive range of applications in diverse fields such as in gas sensors, photocatalysis, lithium ion batteries, H2 production, electrochromic devices, dyed sensitized solar cells, microchip technology, and liquid crystal displays. Tungsten compounds exhibit a more efficient catalytic behavior, and tungsten-dependent enzymes generally catalyze the transfer of an oxygen atom to or from a physiological donor/acceptor with the metal center. Furthermore, tungsten has an n-type semiconductor band gap. Tungsten forms complexes by reacting with several elements such as H, C, N, O, and P as well as other numerous inorganic elements. Interestingly, all tungsten reactions occur at ambient temperature, usually with tetrahydrofuran and dichloromethane under vacuum. Tungsten has extraordinarily high-temperature properties, making it very useful for X-ray production and heating elements in furnaces. Tungsten coordinates with diverse nonmetallic elements and ligands and produces interesting compounds. This article describes an overview of the synthesis of various organometallic compounds of tungsten.

Style APA, Harvard, Vancouver, ISO itp.

33

Nai, Jianwei, Jinliang Wu, Lin Guo i Shihe Yang. "Coordination Polyhedra: A Probable Basic Growth Unit in Solution for the Crystal Growth of Inorganic Nonmetallic Nanomaterials?" Crystal Growth & Design 12, nr 5 (18.04.2012): 2653–61. http://dx.doi.org/10.1021/cg300239c.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

34

Kraposhin, V. S., A. L. Talis, E. D. Demina i A. I. Zaitsev. "Erratum to: Crystal Geometry Mechanism of Intergrowth of Spinel and Manganese Sulfide into a Complex Nonmetallic Inclusion". Metal Science and Heat Treatment 58, nr 9-10 (styczeń 2017): 641. http://dx.doi.org/10.1007/s11041-017-0071-7.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

35

Valeeva A. A. i Gusev A. I. "Placing of hydrogen in titanium oxyhydride". Physics of the Solid State 64, nr 1 (2022): 31. http://dx.doi.org/10.21883/pss.2022.01.52485.202.

Pełny tekst źródła

Streszczenie:

Possible models of the arrangement of hydrogen atoms at the sites of thecubic lattice of titanium oxyhydride TiOyHp with vacancies in the metallic and nonmetallic sublattices are considered. It was found that titaniumoxyhydride retains the B1 type crystal lattice of the initial cubic titaniummonoxide TiOy and contains structural vacancies in the metal and oxygensublattices. Comparison of the found analytical expressions for theintensity of diffraction reflections with experimental X-ray and neutrondiffraction data showed that interstitial H atoms in oxyhydrides occupyvacant octahedral positions 4( b) of the oxygen sublattice. No displacementof H atoms in tetrahedral positions 8( c) is observed. A disorder-orderphase transition channel associated with the formation of an orderedmonoclinic titanium oxyhydride of the Ti5O5 type was found. Thedistribution functions of Ti, O, and H atoms in the partially orderedmonoclinic oxyhydride Ti5.33O5.12H0.74 (Ti0.89O0.85H0.12) with a Ti5O5-typestructure are calculated for the first time, and the concentrations of theseatoms at the positions of its lattice were found. Keywords:Titanium monoxide, Hydrogen, Nonstoichiometry, Vacancies, Octahedral and tetrahedral positions, Distribution function.\

Style APA, Harvard, Vancouver, ISO itp.

36

Валеева, А. А., i А. И. Гусев. "Размещение водорода в оксигидриде титана". Физика твердого тела 64, nr 1 (2022): 33. http://dx.doi.org/10.21883/ftt.2022.01.51828.202.

Pełny tekst źródła

Streszczenie:

Possible models of the arrangement of hydrogen atoms at the sites of the cubic lattice of titanium oxyhydride TiOyHp with vacancies in the metallic and nonmetallic sublattices are considered. It was found that titanium oxyhydride retains the B1 type crystal lattice of the initial cubic titanium monoxide TiOy and contains structural vacancies in the metal and oxygen sublattices. Comparison of the found analytical expressions for the intensity of diffraction reflections with experimental X-ray and neutron diffraction data showed that interstitial H atoms in oxyhydrides occupy vacant octahedral positions 4(b) of the oxygen sublattice. No displacement of H atoms in tetrahedral positions 8(c) is observed. A disorder-order phase transition channel associated with the formation of an ordered monoclinic titanium oxyhydride of the Ti5O5 type was found. The distribution functions of Ti, O, and H atoms in the partially ordered monoclinic oxyhydride Ti5.33O5.12H0.74 (Ti0.89O0.85H0.12) with a Ti5O5-type structure are calculated for the first time, and the concentrations of these atoms at the positions of its lattice were found.

Style APA, Harvard, Vancouver, ISO itp.

37

Bai, Chun Hua, Shui Lin Zheng, Zhi Ming Sun, Shao Min Lei, Jing Ya Gui, Fang Li Lv i Ming Wen. "TiO₂/Kaolinite Photocatalytic Material of Fe³⁺ Chemical Doping and Fe₂O₃ Heat-Banding and its Mechanism Analysis". Advanced Materials Research 178 (grudzień 2010): 324–29. http://dx.doi.org/10.4028/www.scientific.net/amr.178.324.

Pełny tekst źródła

Streszczenie:

It is very prospective to prepare low-cost TiO2/nonmetallic minerals photocatalytic material, which utilizes sun as light source to treatment environmental problems. TiO2/kaolinite nanocomposite was prepared by sol-gel method, using layered kaolinite as substrate and Ti(OC4H9)4 as precursor. The optimum process conditions were achieved. In addition, photocatalytic material was modified by mean of Fe3+chemical doping and Fe2O3 heat-banding to enhance photocatalytic activity. AZO-dye wastewater containing Direct Blue and Direct Purple was treated by these two kinds of photocatalyst under UV-light and sunlight separately. The results showed that both methods improved material photocatalytic activity in some way and the photocatalytic efficiency was raised significantly in sunlight as well as in UV-light. The photocatalytic effect of Fe2O3 heat-banding was superior to Fe3+chemical doping. The characterization of SEM, TEM, AFM shown that the 1-10nm anatase TiO2 crystal grain was doped on surface of the kaolinite particles which is as like as ‘forest on the ground’. To further analyze the mechanism of the material, XPS was adopted to analyses the chemical composition, elements, valence state.

Style APA, Harvard, Vancouver, ISO itp.

38

Løvvik, Ole Martin, Ole Swang i Susanne M. Opalka. "Modeling alkali alanates for hydrogen storage by density-functional band-structure calculations". Journal of Materials Research 20, nr 12 (1.12.2005): 3199–213. http://dx.doi.org/10.1557/jmr.2005.0397.

Pełny tekst źródła

Streszczenie:

The alanates (complex aluminohydrides) have relatively high gravimetric hydrogen density and are among the most promising solid-state hydrogen-storage materials. In this work, the crystal structure and electronic structure of pure and mixed-alkali alanates were calculated by ground-state density-functional band-structure calculations. The results are in excellent correspondence with available experimental data. The properties of the pure alanates were compared, and the relatively high stability of the Li3AlH6 phase was pointed out as an important difference that may explain the difficulty of hydrogenating lithium alanate. The alkali alanates are nonmetallic with calculated band gaps around 5 eV and 2.5–3 eV for the tetra- and hexahydrides. The bonding was identified as ionic between the alkali cations and the aluminohydride complexes, while it is polar covalent within the complex. A broad range of hypothetical mixed-alkali alanate compounds was simulated, and four were found to be stable compared to the pure alanates and each other: LiNa2AlH6, K2LiAlH6, K2NaAlH6, and K2.5Na0.5AlH6. No mixed-alkali tetrahydrides were found to be stable, and this was explained by the local coordination within the different compounds. The only alkali alanate that seemed to be close to fulfilling the international hydrogen density targets was NaAlH4.

Style APA, Harvard, Vancouver, ISO itp.

39

Shakhov, S. I., i K. N. Vdovin. "Electromagnetic stirring in billet CCM molds and continuously casted billet quality". Ferrous Metallurgy. Bulletin of Scientific , Technical and Economic Information 75, nr 8 (6.09.2019): 955–61. http://dx.doi.org/10.32339/0135-5910-2019-8-955-961.

Pełny tekst źródła

Streszczenie:

Electromagnetic stirring (EMS) is one of methods to improve the quality of continuously casted billet. Under EMS impact nonmetallic inclusions are removed out of the solidification area and move to the center of meniscus of liquid metal. Besides, high speeds of convection flows in the liquid metal avoid the remaining of gases at the crystallization border and decrease therefore the number of gas bubbles under metal shell. This mechanism of EMS action in a mold results in decreasing of gas bubbles under the metal shell and impurities in continuously casted billet. Operation of a billet CCM was studied at Moldavsky steel-works, where an EMS stator was imbedded into the mold. Influence of EMS on the quality of continuously casted billet was studied. The work was accomplished in several stages. First, the EMS system with a test mold with electromagnetic stirrer was studied for casting of 135×135 mm billets and 800 mm long, next 125×125 mm billet and 1000 mm long and then 125×125 mm billet and 800 mm long. Main comparative parameters of used EMS systems in the mold presented in the article. All the molds-EMS systems were designed based on existing regular molds so that they could be installed at the CCM without changing the existing oscillation frame and water input and output piping. As a result of templates metal science studies cut out of test and regular metal, influence of EMS in the mold on the billet macro structure was revealed, comparing with a standard strand. The following phenomena were studied: decrease of average degree of cracks and liquation strips along the billet section, of cracks in the billet axis zone, central pore volume and border point contaminations; increase of axis liquation degree (but liquation became more distributed), decrease of carbon axis liquation coefficient in high carbon steels. The average growth values of equiaxed crystal zone at the templates of test heats with EMS amounted for 55% at high carbon steels comparing with regular billet templates, at the middle carbon steels – 48%, at the low carbon steels – 92%. The elaborated EMS system in the mold allows improving considerably the quality of continuously casted billets.

Style APA, Harvard, Vancouver, ISO itp.

40

Maris, H. J., i S. Tamura. "Propagation of acoustic phonon solitons in nonmetallic crystals". Physical Review B 84, nr 2 (11.07.2011). http://dx.doi.org/10.1103/physrevb.84.024301.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

41

Syers, Paul, i Johnpierre Paglione. "Ambipolar surface state transport in nonmetallic stoichiometric Bi2Se3 crystals". Physical Review B 95, nr 4 (17.01.2017). http://dx.doi.org/10.1103/physrevb.95.045123.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

42

Zhuang, Bihao, Zicong Jin, Jiahuan Deng, Hui Xiong, Wenzhe Li i Jiandong Fan. "Regulating Exciton Diffusion in Antimony‐Based Perovskite‐Like Single Crystals toward Highly Efficient and Stable Luminescence". Advanced Optical Materials, 11.08.2023. http://dx.doi.org/10.1002/adom.202300888.

Pełny tekst źródła

Streszczenie:

AbstractOrganic‐inorganic hybrid metal halide perovskite has played an important role in optoelectronics and photonics due to their extremely high photoluminescence quantum yield (PLQY). However, considering the strong nonmetallic property of antimony (Sb), the excitons in antimony‐based single crystals are usually dissipated in the form of non‐radiative recombination under organic‐inductive effect, which leads to the low PLQY. Herein, two kinds of perovskite‐like single crystals, i.e., (8‐HQ)2SbCl3 and (8‐HQH)SbCl4, are innovatively grown. The density functional theory (DFT) calculations reveal that the unique luminescence characteristics are associated with the inductive effect of organic coordination and exciton effect in the metal octahedral skeleton. When Cl− replaces the organic ligand in (8‐HQ)2SbCl3, the inductive effect is reduced while the self‐trapped exciton effect in the metal octahedron is enhanced. Besides, the theoretical research on electron transmission in a modeling device reveals that the hydrogen bond of organic A‐site in the single crystal promotes the transition of electrons. Based on the luminescent properties of (8‐HQH)SbCl4, the white LED devices are obtained by coating (8‐HQH)SbCl4 and red phosphor on 450 nm LED chips.

Style APA, Harvard, Vancouver, ISO itp.

43

Menabde, Sergey G., Jacob T. Heiden, Joel D. Cox, N. Asger Mortensen i Min Seok Jang. "Image polaritons in van der Waals crystals". Nanophotonics, 4.01.2022. http://dx.doi.org/10.1515/nanoph-2021-0693.

Pełny tekst źródła

Streszczenie:

Abstract Polaritonic modes in low-dimensional materials enable strong light–matter interactions and the manipulation of light on nanometer length scales. Very recently, a new class of polaritons has attracted considerable interest in nanophotonics: image polaritons in van der Waals crystals, manifesting when a polaritonic material is in close proximity to a highly conductive metal, so that the polaritonic mode couples with its mirror image. Image modes constitute an appealing nanophotonic platform, providing an unparalleled degree of optical field compression into nanometric volumes while exhibiting lower normalized propagation loss compared to conventional polariton modes in van der Waals crystals on nonmetallic substrates. Moreover, the ultra-compressed image modes provide access to the nonlocal regime of light–matter interaction. In this review, we systematically overview the young, yet rapidly growing, field of image polaritons. More specifically, we discuss the dispersion properties of image modes, showcase the diversity of the available polaritons in various van der Waals materials, and highlight experimental breakthroughs owing to the unique properties of image polaritons.

Style APA, Harvard, Vancouver, ISO itp.

44

Zhao, Liu 赵柳, Zhiqiang Zhang i Xiangqing Kong. "Restricted phase space thermodynamics of charged AdS black holes in conformal gravity". Chinese Physics C, 24.07.2023. http://dx.doi.org/10.1088/1674-1137/ace9c2.

Pełny tekst źródła

Streszczenie:

Abstract The thermodynamics of charged spherically symmetric AdS black holes in conformal gravity is revisited using the recently proposed restricted phase space (RPS) formalism. This formalism avoids all the bizarreness that arose in the extended phase space formalism for this model. It is found that the charged AdS black holes in this model may belong to a new universality class which is different from all previously studied cases under the RPS formalism. Besides the distinguished isocharge $T-S$ and isothermal $\Phi-Q_e$ behaviors, the absence of Hawking-Page transition is another notable feature. On the other hand, in the high temperature limit, the thermodynamic behavior of the present model become exactly the same as that of the Einstein gravity and the black hole scan models, which add further evidence for the universality of the recently reported correspondence between high temperature AdS black holes and low temperature quantum phonon gases in nonmetallic crystals. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Style APA, Harvard, Vancouver, ISO itp.

45

"Nonmetallic Crystals Herausgegeben: Von S. C. Jain und L. T. Chadderton; Gordon and Breach Science Publishers, London, New York, Paris 1970; 335 Seiten mit zahlreichen Bildern und Tabellen; Format 19,5 × 26,5 cm; Ln. £ 11 5 s". Zeitschrift für Chemie 13, nr 10 (1.09.2010): 399–400. http://dx.doi.org/10.1002/zfch.19730131035.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

Artykuły w czasopismach na temat „Nonmetallic crystals”

Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych