Artykuły w czasopismach: „Hot Stage Optical Microscopy”

1

Maeda, Yoji, i Mitsuo Koizumi. "New high‐pressure hot stage for optical microscopy". Review of Scientific Instruments 67, nr 5 (maj 1996): 2030–31. http://dx.doi.org/10.1063/1.1146965.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

2

Tick, P. A., K. E. Lu, S. Mitachi, T. Kanamori i S. Takahashi. "Hot stage optical microscopy studies of crystallization in fluoride glass melts". Journal of Non-Crystalline Solids 140 (styczeń 1992): 275–80. http://dx.doi.org/10.1016/s0022-3093(05)80781-1.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

3

Lu, Q. M., i M. Libera. "Microstructural measurements of amorphous GeTe crystallization by hot‐stage optical microscopy". Journal of Applied Physics 77, nr 2 (15.01.1995): 517–21. http://dx.doi.org/10.1063/1.359034.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

4

Ji, Ze Sheng, Sumio Sugiyama i Jun Yanagimoto. "Microstructure Changes in Alloy AZ31B in Semisolid State and Its Mechanical Properties". Solid State Phenomena 116-117 (październik 2006): 159–62. http://dx.doi.org/10.4028/www.scientific.net/ssp.116-117.159.

Pełny tekst źródła

Streszczenie:

The structural changes of the wrought magnesium alloy AZ31B in semisolid state were clarified using optical microscopy and hot-stage microscopy. The influence of heat treatment variables was assessed. Compression tests covering a range from room temperature to 673 K were carried out for mechanical property assessment; flow stress and breaking strain were determined. The following are the results: (1) The grain growth of the hot-extruded AZ31B without preprocessing sensitively reacted at temperature and retention time. (2) The hot-extruded AZ31B with 30 % preprocessing showed an almost perfectly spheroidized structure in a semisolid state under certain conditions. (3) Heating velocity markedly affected the spheroidizing rate of grains. (4) From the direct observation of the hot-extruded alloy AZ31B by hot-stage microscopy, spheroidization was observed in some crystal populations. (5) Spheroided materials in the semisolid temperature range had a lower flow stress and a larger breaking strain than nonspheroidized materials. These results indicate the possibility of manufacturing wrought magnesium alloy by cold working.

Style APA, Harvard, Vancouver, ISO itp.

5

Zhang, Bo Hou, Bo Long Li, Peng Qi, Ning Li, Tong Bo Wang i Zuo Ren Nie. "Mechanical Behavior and Microstructure of Hot Deformation of with Er 7N01 Aluminum Alloy". Materials Science Forum 993 (maj 2020): 294–98. http://dx.doi.org/10.4028/www.scientific.net/msf.993.294.

Pełny tekst źródła

Streszczenie:

In this paper, an Al-Zn-Mg-Cu alloy with a small amount of Er and Zr added was used as the research object. The homogenization annealing was carried out, and the 7N01 aluminum alloy was used at 300 °C, 350 °C, 400 °C, 450 °C and 0.1 s-1, 1 s-1, 10 s-1 deformation conditions by Gleeble-3500 thermal simulator. Optical Microscopy (OM), Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Transmission Electron Microscopy (TEM) were used for microstructure analysis. The results show that the stress-strain curve of with Er 7N01 aluminum alloy can be divided into micro-strain stage, uniform deformation stage and steady-state flow stage during the thermal compression process. The flow stress of 7N01 aluminum alloy achieved peaks at the initial stage of strain, and then increased with the increase of strain rate and the decrease of deformation temperature. With the increase of deformation temperature and the decrease of deformation rate, the recrystallization process was significantly increased.

Style APA, Harvard, Vancouver, ISO itp.

6

Kobayashi, Sengo, Kiyomichi Nakai i Yasuya Ohmori. "Analysis of Phase Transformation in a Ti-10 mass%Zr Alloy by Hot Stage Optical Microscopy". MATERIALS TRANSACTIONS 42, nr 11 (2001): 2398–405. http://dx.doi.org/10.2320/matertrans.42.2398.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

7

Enose, Arno A., Priya K. Dasan, H. Sivaramakrishnan i Sanket M. Shah. "Formulation and Characterization of Solid Dispersion Prepared by Hot Melt Mixing: A Fast Screening Approach for Polymer Selection". Journal of Pharmaceutics 2014 (12.03.2014): 1–13. http://dx.doi.org/10.1155/2014/105382.

Pełny tekst źródła

Streszczenie:

Solid dispersion is molecular dispersion of drug in a polymer matrix which leads to improved solubility and hence better bioavailability. Solvent evaporation technique was employed to prepare films of different combinations of polymers, plasticizer, and a modal drug sulindac to narrow down on a few polymer-plasticizer-sulindac combinations. The sulindac-polymer-plasticizer combination that was stable with good film forming properties was processed by hot melt mixing, a technique close to hot melt extrusion, to predict its behavior in a hot melt extrusion process. Hot melt mixing is not a substitute to hot melt extrusion but is an aid in predicting the formation of molecularly dispersed form of a given set of drug-polymer-plasticizer combination in a hot melt extrusion process. The formulations were characterized by advanced techniques like optical microscopy, differential scanning calorimetry, hot stage microscopy, dynamic vapor sorption, and X-ray diffraction. Subsequently, the best drug-polymer-plasticizer combination obtained by hot melt mixing was subjected to hot melt extrusion process to validate the usefulness of hot melt mixing as a predictive tool in hot melt extrusion process.

Style APA, Harvard, Vancouver, ISO itp.

8

Han, P. D., A. Asthana, Z. Xu i D. A. Payne. "Growth twins in Bi2Ca1Sr2Cu2O8 superconductor single crystals". Journal of Materials Research 5, nr 5 (maj 1990): 909–12. http://dx.doi.org/10.1557/jmr.1990.0909.

Pełny tekst źródła

Streszczenie:

Large-scale twin structures in single crystal Bi2Ca1Sr2Cu2O8 (2122) are reported for the first time. Symmetrical 90° (i.e., a-b) twins with a [110] type twin boundary were observed. A characteristic layer-growth morphology and jagged twin walls suggest that twin formation occurred layer by layer during crystal growth; i.e., the twins were growth twins. Hot-stage optical microscopy, x-ray diffraction, and electron microscopy results are discussed with reference to twin morphology.

Style APA, Harvard, Vancouver, ISO itp.

9

Smith, Ronald W. "The Staining of Polymers". Microscopy Today 10, nr 5 (wrzesień 2002): 5–7. http://dx.doi.org/10.1017/s1551929500058272.

Pełny tekst źródła

Streszczenie:

In the beginning there was water-the first stain that delineated structure within a polymeric system. The polymerwas natural rubber (NR) and the system was an air-dried film of natural latex. Grenquist reported in 1929 that a dried film of natural rubber latex soaked in hot water became milky (Figure 1) and, at that stage, the latex particles could be detected by the optical microscope (OM), The contrast mechanism was provided by the absorption of water by the naturally occurring proteinaceous layers present on the congealed NR particle surfaces. There was little demand for polymer staining until the age of electron microscopy.

Style APA, Harvard, Vancouver, ISO itp.

10

Journal, Baghdad Science. "Liquid crystalline dendrimer: Sythesis and Chracterization". Baghdad Science Journal 11, nr 2 (1.06.2014): 491–501. http://dx.doi.org/10.21123/bsj.11.2.491-501.

Pełny tekst źródła

Streszczenie:

A new family of nematic liquid crystal dendrimers derived from 3,5-dihydroxybenzoic acid were synthesized. The synthesis of the dendrimers compounds shows the influence of the dendritic core on the mesomorphic properties. The liquid crystalline properties were studied by polarizing optical microscopy (POM) equipped with a hot stage, the structures of the synthesized compounds characterized using FTIR and 1HNMR spectroscopy.

Style APA, Harvard, Vancouver, ISO itp.

11

Roudini, Danesh. "Synthesis and Properties of Novel Thiophene-Based Liquid Crystalline Conducting Polymers". Polymers and Polymer Composites 25, nr 9 (listopad 2017): 669–76. http://dx.doi.org/10.1177/096739111702500904.

Pełny tekst źródła

Streszczenie:

Side-chain liquid crystalline polythiophenes were synthesised and the effects of the mesogenic units on the structure and electronic properties of the polymers were studied. The liquid crystal properties of the polymer films were studied using polarised hot-stage optical microscopy and differential scanning calorimetry, and X-ray diffractometry was used to investigate the effect of a magnetic field on the monomers and polymers.

Style APA, Harvard, Vancouver, ISO itp.

12

Maeda, Y., i M. Koizumi. "New High-pressure Hot Stage for Optical Microscopy: In situ Observation of Texture of Liquid Crystals under Hydrostatic Pressure." REVIEW OF HIGH PRESSURE SCIENCE AND TECHNOLOGY 7 (1998): 1532–34. http://dx.doi.org/10.4131/jshpreview.7.1532.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

13

Andjeli?, Sa?a, Dennis Jamiolkowski, James McDivitt, Jerome Fischer i Jack Zhou. "Spherulitic growth rates and morphology of absorbable poly(p-dioxanone) homopolymer and its copolymer by hot-stage optical microscopy". Journal of Polymer Science Part B: Polymer Physics 39, nr 24 (2001): 3073–89. http://dx.doi.org/10.1002/polb.10065.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

14

Labun, P. A., P. A. Crazier i T. Suzuki. "Transmission electron microscopy studies of Bi-substituted garnet films". Proceedings, annual meeting, Electron Microscopy Society of America 49 (sierpień 1991): 774–75. http://dx.doi.org/10.1017/s042482010008818x.

Pełny tekst źródła

Streszczenie:

Bi-substituted garnet films have attracted much attention as possible materials for high density magneto-optical recording media. Recently a new rapid thermal annealing technique has been developed to produce garnet films with improved microstructural and magnetic properties. We have employed in-situ heating in an analytical electron microscope to characterize the microstructural changes to the morphology and chemistry during thermal annealing of garnet films.Garnet films were produced by an r.f. magnetron sputter deposition method in an Ar atmosphere. The nominal composition of the films was (BiDy)3(FeGa)5O12 with a thickness of ∼ 40 nm. The films were transferred into the hot stage of a Philips 400T transmission electron microscope and heated to a maximum temperature of 720 C. Different rates were used to simulate the effect of heat pulsed annealing.

Style APA, Harvard, Vancouver, ISO itp.

15

Journal, Baghdad Science. "Synthesis and Characterization of New Mesomorphic Azo Compounds and Study their Photoluminesecence Properties". Baghdad Science Journal 13, nr 2 (5.06.2016): 333–44. http://dx.doi.org/10.21123/bsj.13.2.333-344.

Pełny tekst źródła

Streszczenie:

The preparation of a new Azo compounds of highly conjugated dimeric and polymeric liquid crystal to achieve the crystalline characteristics Which have structures assigned based on elemental analysis, IR 1HNMR and CHNS-O while mesogenic properties have been set for DSC and hot-stage polarizing optical microscopy. The compounds show enantiotropicnematic phase being displayed. The compounds show photoluminescence properties in the organic solution at room temperature, with the fluorescence band centered around 400 nm.

Style APA, Harvard, Vancouver, ISO itp.

16

Srilekha, Gandu, Pokkunuri Pardhasaradhi, Boddapati Taraka Phani Madhav i Manepalli Ramakrishna Nanchara Rao. "Effect of ZnO nanoparticles on optical textures and image analysis properties of 7O.O5 liquid crystalline compound". Zeitschrift für Naturforschung A 76, nr 4 (18.02.2021): 349–59. http://dx.doi.org/10.1515/zna-2020-0302.

Pełny tekst źródła

Streszczenie:

Abstract The systematic studies are carried out on liquid crystalline N-(p-n-heptyloxybenzylidene)-p-n-pentyloxy aniline (7O.O5) pure compound and with dispersion of ZnO nanoparticles in 1 wt% respectively. The phase transition studies of the pure and LC nanocomposite are carried out using Polarizing Optical Microscope (POM) attached with hot stage along with digital camera and Differential Scanning Calorimetry (DSC) is used to measure enthalpy and transition temperature values. Further the presence of ZnO nano particles in 7O.O5 is determined by Scanning Electron Microscopy (SEM) analysis. It is identified that due to dispersion of nano particles SmG phase is Quenched and nematic thermal range is increased. To enhance the captured textural images, an algorithm that uses tuned intensification operators have been proposed in this article. Statistical parameters for enhanced output images are calculated and compared with existing algorithms such as Adaptive Gamma Correction (AGC) and Discrete Wavelet Transform – Singular Value Decomposition (DWT-SVD) to understand the effectiveness of proposed algorithm. Further, optical parameters have been computed to understand the thermo optical nature of liquid crystalline compounds.

Style APA, Harvard, Vancouver, ISO itp.

17

Zhao, Yu Lei, Wei Min Zhang, Ji Lei Li, Fan Fan Yu i Jia Ling Pu. "Synthesis and Performance of a Novel Coumarin-Containing Side-Chain Liquid Crystalline Polymer". Solid State Phenomena 181-182 (listopad 2011): 197–200. http://dx.doi.org/10.4028/www.scientific.net/ssp.181-182.197.

Pełny tekst źródła

Streszczenie:

A new type of able liquid crystalline polymer with a coumarin-containing mesogenic side group that could be photo-crosslinked was synthesized in this paper. The structure of the intermediates, monomers and polymers were characterized with FTIR and 1HNMR measurement. DSC, TG, and hot stage polarized optical microscopy were employed to study the phase transition temperature, mesophase texture, and thermal stability of the liquid crystalline polymers. The results indicated that both the monomer and polymer exhibited liquid-crystalline features over a wide temperature range.

Style APA, Harvard, Vancouver, ISO itp.

18

Ma, Qing Lan, i Yuan Ming Huang. "Dependence of the Morphology of Polymer Dispersed Liquid Crystal on Temperature". Materials Science Forum 663-665 (listopad 2010): 804–7. http://dx.doi.org/10.4028/www.scientific.net/msf.663-665.804.

Pełny tekst źródła

Streszczenie:

Polymer dispersed liquid crystal film was prepared by the method of polymerization induced phase separation. The optical morphologies of the PDLC film were characterized by polarized optical microscope with a hot stage. Our results demonstrated that the morphology of the PDLC film depended on temperature of PDLC system.

Style APA, Harvard, Vancouver, ISO itp.

19

Tseronis, D., I. F. Sideris, C. Medrea i Ionel Chicinaş. "Microscopic Examination of the Fracture Surfaces of an H 13 Hot Extrusion Die due to Failure at the Initial Usage Stage". Key Engineering Materials 367 (luty 2008): 177–84. http://dx.doi.org/10.4028/www.scientific.net/kem.367.177.

Pełny tekst źródła

Streszczenie:

This paper studies the fracture surfaces of an aluminium hot extrusion die that broke down during operation. The die was constructed, from H13 steel and was intended for the production of 60,000 Kg of aluminium profile. The male part fractured during operation after the production of 500 Kg profile. Initially, the machine and thermal treatments that were applied for construction of the die were collected and studied. The die was carefully inspected visually with a stereoscope. The fracture surfaces, some cracks, and the structure that was not affected by the failure, were investigated by optical microscopy. The thickness, quality and homogeneity of the nitrated layers were inspected. Additional information concerning the fracture was obtained by examining a primary crack using a scanning electron microscope and chemical analysis of the material was made using EDX attachment. The paper reports on some interesting observations relating to the fractured component, the type of the fractures, and the quality of the heat treatments, and presents some of the probable causes that led to the premature failure of the die.

Style APA, Harvard, Vancouver, ISO itp.

20

Mirnaya, T. A., V. S. Dradrah i G. G. Yaremchuk. "Mesophase and Glass Formation in Binary Systems of Caesium and Alkali-Earth Metal Butyrates". Zeitschrift für Naturforschung A 54, nr 12 (1.12.1999): 685–88. http://dx.doi.org/10.1515/zna-1999-1204.

Pełny tekst źródła

Streszczenie:

Abstract The phase diagrams of the binary systems of non-mesomorphic components such as caesium-mag-nesium, caesium-calcium and caesium-barium butyrates have been studied by differential thermal analysis and hot stage polarization microscopy. Smectic liquid crystals are found in some composition ranges of the binaries with calcium and barium butyrates. The liquid crystal appearance in these systems is explained by the exhibition of latent mesomorphism of caesium butyrate. Glasses are obtained in all systems studied, the formation of vitreous optical anisotropic mesophase being revealed only for binary from caesium and barium butyrates.

Style APA, Harvard, Vancouver, ISO itp.

21

Arstila, Hanna, Mikko Tukiainen, Susanne Taipale, Minna Kellomäki i Leena Hupa. "Liquidus Temperatures of Bioactive Glasses". Advanced Materials Research 39-40 (kwiecień 2008): 287–92. http://dx.doi.org/10.4028/www.scientific.net/amr.39-40.287.

Pełny tekst źródła

Streszczenie:

Melts in the composition range of bioactive glasses have their liquidus temperatures within or close to the working range. Additionally, bioactive glasses show a strong tendency to crystallization due to their composition. Thus, many bioactive glass compositions are unsuitable for demanding working procedures such as fiber drawing. In this work we discuss the suitability of different methods for measuring liquidus temperature of bioactive glasses. Thermal analysis was used, and complemented by sintering curves as given by hot stage microscopy. Hot stage microscopy could be used to measure liquidus also when the thermal effect associated with liquidus was low and consequently the DTA was not suitable. Liquidus of some glasses was measured with optical microcopy for samples heat treated in a gradient furnace. The values indicating the crystallization of the samples during viscosity measurement with rotational viscosimeter were compared with the other measurements. The crystalline phases formed at liquidus were identified with XRD and SEM-EDXA. The measured liquidus temperatures were also tested by drawing fibers directly from molten glass and from preforms heated to typical fiber drawing viscosity values. For all compositions the fiber drawing viscosity values were below liquidus. Continuous fibers could be manufactured of compositions only with low rates of crystal nucleation and growth.

Style APA, Harvard, Vancouver, ISO itp.

22

Bashir, Z., i N. Khan. "Correlation of observations made by DSC and hot-stage optical microscopy of the thermal properties of a monotropic liquid-crystal polyester". Thermochimica Acta 276 (kwiecień 1996): 145–60. http://dx.doi.org/10.1016/0040-6031(95)02756-4.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

23

Hawaldar, Ranjit R., A. M. Funde, D. Bhange, V. Ramaswamy, Sandesh R. Jadkar, S. D. Sathaye, Uttam Mulik i Dinesh Amalnerkar. "Nanostructured Thin films of Anthracene by Liquid-Liquid Interface Recrystallization Technique". Solid State Phenomena 119 (styczeń 2007): 27–34. http://dx.doi.org/10.4028/www.scientific.net/ssp.119.27.

Pełny tekst źródła

Streszczenie:

Herein, we report the fabrication of anthracene nanostructures and, in turn, their thin films at the air-water interface by recrystallization at the liquid-liquid interface. This method is simple, inexpensive and allows the deposition of anthracene nanoparticulate thin films on large and a variety of substrates. The virgin films were characterized by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Hot Stage Polarizing Microscopy and UV-Visible spectroscopy. Interestingly, it was found that these thin films are comprised of nanosized bushy clusters of anthracene molecules as revealed by TEM. Also, with increase in the thickness of the films, the formation of irregular microtapes was evinced by SEM. The absorption spectra reveals the presence of 2 excitonic peaks for the lowest dip sample (10 dips) whereas the spectra recorded for higher dip samples (20 dips, 30dips, 40dips) closely match with that of pure anthracene in chloroform solution. The dramatic reduction in the melting point as revealed by hot stage polarizing microscopy is the salient feature of the work.

Style APA, Harvard, Vancouver, ISO itp.

24

Wicaksono, Yudi, Dwi Setyawan i Siswandono Siswandono. "Analysis of Solid-State Interactions of Ketoprofen-Coformer Binary Mixtures by DSC and Hot Stage Microscopy". Molekul 15, nr 2 (27.07.2020): 121. http://dx.doi.org/10.20884/1.jm.2020.15.2.638.

Pełny tekst źródła

Streszczenie:

Ketoprofen is a non-steroidal anti-inflammatory drug with poor water solubility, so the absorption is less than optimal. One method to improve the solubility of ketoprofen is through the formation of multicomponent solid forms. The success of the formation of the multicomponent solid forms is strongly influenced by interactions between components in their solids. In this study, the analysis of the interactions in solid form of ketoprofen-coformers was carried out using the differential scanning calorimetry (DSC) and hot stage microscopy (HSM) with adipic acid and isonicotinamide as coformers. From the experimental results, the mixtures of ketoprofen-adipic acid show a solid-liquid phase diagram that indicates a simple eutectic system with eutectic points on the molar fraction of ketoprofen 0.9 and temperature at 92.9 °C. The ketoprofen-isonicotinamide mixtures have a eutectic system with the peritectic point. The solid-liquid phase diagram has indicated that the ketoprofen-adipic acid in eutectic composition forms a miscible liquid phase without interaction in its solid form, whereas the ketoprofen-isonicotinamide forms a miscible liquid phase accompanied by interaction with the excess component. The results of the HSM analysis showed the same phenomenon as the result of the DSC experiment and have confirmed with the FTIR analysis

Style APA, Harvard, Vancouver, ISO itp.

25

Qi, Kai Liang, Guang Cheng Zhang, Song Ming Li, Liang Wei Liu i Zhen He. "Preparation and Properties of High Performance Polyimide Foam". Advanced Materials Research 221 (marzec 2011): 66–71. http://dx.doi.org/10.4028/www.scientific.net/amr.221.66.

Pełny tekst źródła

Streszczenie:

High performance polyimide (PI) foam has been prepared by esterification method using benzophenone tetracarboxylic acid dianhydride (BTDA) and diamino diphenylmethane (MDA) as the main materials in the mixture of methanol and tetrahydrofuran (THF). The cellular structure, thermal properties and flame retardance properties of PI foam were characterized by hot stage optical microscopy, scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetic analysis (TGA) and limiting oxygen Index (LOI), respectively. The results showed that the cellular structure was more ideal when the particle diameter of polyester ammonium salt (PEAS) precursor powder was 100μm; the glass transition temperature (Tg) of PI foam was more than 300°C, 5% weight loss temperature was above 500°C, LOI was as high as 50% and sound absorption was over 0.5.

Style APA, Harvard, Vancouver, ISO itp.

26

Buchko, C. J., P. M. Wilson, Z. Xu, J. Zhang, S. Lee, J. S. Moore i D. C. Martin. "Electron microscopy and diffraction of crystalline dendrimers and macrocycles". Proceedings, annual meeting, Electron Microscopy Society of America 51 (1.08.1993): 1218–19. http://dx.doi.org/10.1017/s0424820100151921.

Pełny tekst źródła

Streszczenie:

The synthesis of well-defined organic molecules with unique geometries opens new opportunities for understanding and controlling the organization of condensed matter. Here, we study dendrimers and macrocycles which are synthesized from rigid phenyl-acetylene spacer units, Both units are solubilized by the presence of tertiary butyl groups located at the periphery of the molecule. These hydrocarbon materials form crystalline and liquid crystalline phases which have been studied by differential scanning calorimetry, hot stage optical microscopy, and wide-angle x-ray scattering (WAXS).The precisely defined architecture of these molecules makes it possible to investigate systematic variations in chemical architecture on the nature of microstructural organization. Here we report on the transmission electron microscopy (TEM), selected area electron diffraction (SAED), and high resolution electron microscopy (HREM) studies of crystalline thin films formed by deposition of these materials onto carbon substrates from dilute solution. Electron microscopy is very attractive for gaining structural information on new molecules due to the scarcity of material to grow single crystals suitable for conventional crystallography.

Style APA, Harvard, Vancouver, ISO itp.

27

Li, H. F., i R. V. Ramanujan. "In situ hot stage transmission electron microscopy observations of nanocrystal formation in a Co65Si15B14Fe4Ni2 amorphous magnetic alloy". Thin Solid Films 514, nr 1-2 (sierpień 2006): 316–22. http://dx.doi.org/10.1016/j.tsf.2006.02.093.

Pełny tekst źródła

Style APA, Harvard, Vancouver, ISO itp.

28

Lu, Wei Zhong, Chun Wei i Qui Shan Gao. "Synthesis and Properties of Thermotropic Liquid Crystalline Polyesters with Flexible Polymethylene Spacer". Key Engineering Materials 428-429 (styczeń 2010): 126–31. http://dx.doi.org/10.4028/www.scientific.net/kem.428-429.126.

Pełny tekst źródła

Streszczenie:

Polymethylene bis(p-hydroxybenzoates) were prepared from methyl p-hydroxybenzoate and different diols by melted transesterification reaction. Three liquid crystalline polyesters were synthesized from terephthaloyl dichloride and polymethylene bis(p-hydroxybenzoates). Its structure, morphology and properties were characterized by Ubbelohde viscometer, Fourier transform infrared spectroscopy (FT-IR), Differential scanning calorimetry (DSC), polarized optical microscopy (POM) with a hot stage, and wide-angle X-ray diffraction (WAXD). Results indicated that the intrinsic viscosities were between 0.088 and 0.210 dL/g. Optical microscopy showed that the TLCP has a highly threaded liquid crystalline texture and a high birefringent schlieren texture character of nematic phase and has wider mesophase temperature ranges for all polyesters. DSC analysis were found that the melting point (Tm), isotropic temperature (Ti) of TLCPs decreased and the temperature range of the liquid crystalline phase became wider with increased number of methylene spacers in the polyester. The WAXD results showed that TLCPs owned two strong diffraction peaks at 2θ near 19° and 23°.

Style APA, Harvard, Vancouver, ISO itp.

29

Su, Rui Ming, Ying Dong Qu, Run Xia Li i Rong De Li. "Study of Solid Solution Treatment on Spray Deposited 7A04 Alloy". Applied Mechanics and Materials 217-219 (listopad 2012): 1853–56. http://dx.doi.org/10.4028/www.scientific.net/amm.217-219.1853.

Pełny tekst źródła

Streszczenie:

The Al-Zn-Mg-Cu (7A04) alloys were prepared by using the method of spraying deposition and the hot extrusion. The effects of two-stage solid solution treatment and single solid solution treatment on the microstructure and mechanical properties of spray deposited 7A04 alloy were investigated. The microstructure and mechanical properties were observed and tested by optical microscopy, SEM, X-ray diffraction and other methods. It is indicated that the two-stage solid solution treatment is better than the single. After the two-stage solid solution, the sizes of recrystallization grains were small and a lot of precipitations were dissolved. And the microstructure was nice by ageing treatment. The tensile strength and elongation of the alloy can respectively reach 740MPa and 5.8 percent by the two-stage solid solution (at 450°C for 1 hour and 475°C for 2 hours) and the aging treatment.

Style APA, Harvard, Vancouver, ISO itp.

30

Prokoshkina, Vera, Liudmila M. Kaputkina, A. G. Svyazhin i J. Siwka. "Structure Formation and Strengthening of Hot Deformed Nitrogen-Containing Steels". Advances in Science and Technology 56 (wrzesień 2008): 116–21. http://dx.doi.org/10.4028/www.scientific.net/ast.56.116.

Pełny tekst źródła

Streszczenie:

The structural and phase transformations and the strengthening of nitrogen-containing steels resulting from alloying and thermomechanical treatment have been investigated using X-ray diffraction analysis, optical microscopy, hardness measurements and tensile testing. For the modeling of thermomechanical treatment processes, a DIL 805A/D dilatometer with a deformation capability and a Gleeble 3800 simulator were used. Rational nitrogen or nitrogen plus carbon concentrations are determined by basic composition of an alloy. They are limited by the processes of precipitation of excess phases during crystallization and their dissolution during heating stage of the thermal or thermomechanical treatment. Combined alloying by carbon and nitrogen leads to significant complication of phase and structural transformations in steels, including hot deformation that manifests itself in changes of strain-stress diagram parameters. Effectiveness of increasing of a hot deformation resistance under alloying by nitrogen and carbon depends on a basic composition of steel, C/N ratio and temperature-strain rate deformation conditions.

Style APA, Harvard, Vancouver, ISO itp.

31

Sowmya, P. T., i K. M. Lokanatha Rai. "Synthesis and Liquid Crystalline Properties of a New Homologous Series of 4,5-Disubstituted 2H-[1,2,3]-Triazoles via Azide-Chalcone Oxidative Cycloaddition Reaction". Australian Journal of Chemistry 70, nr 7 (2017): 764. http://dx.doi.org/10.1071/ch16540.

Pełny tekst źródła

Streszczenie:

A new homologous series of 4,5-disubstituted 2H-[1,2,3]-triazole derivatives were synthesized from chalcones and sodium azide via oxidative cycloaddition reaction; CuI was used as catalyst. Flexibility in the synthesized molecules was provided by attaching straight alkoxy chains. The synthesized compounds were characterized by elemental analysis, and 1H NMR and 13C NMR and LC-MS spectroscopies . The stability and range of the mesophases increased with the length of the chain on the triazoles. The melting point, transition temperatures, and enantiotropic liquid crystal morphologies were determined by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) equipped with a hot stage.

Style APA, Harvard, Vancouver, ISO itp.

32

Mirnaya, T. A., Y. V. Bereznitski i S. V. Volkov. "Liquid Crystals and Glasses in Binary Systems from Sodium and Alkali-Earth Metal Butyrates". Zeitschrift für Naturforschung A 51, nr 7 (1.07.1996): 867–70. http://dx.doi.org/10.1515/zna-1996-0711.

Pełny tekst źródła

Streszczenie:

Abstract The temperature and composition ranges of liquid crystal and glass formation have been established for the binary mixtures of mesogenic sodium butyrate with non-mesogenic magnesium, calcium and strontium butyrates by means of differential thermal analysis and hot stage polarization microscopy. The formation of a vitreous optically anisotropic mesophase has been found for binaries of sodium butyrate with calcium and strontium butyrates.

Style APA, Harvard, Vancouver, ISO itp.

33

Aryshenskii, Evgeniy V., Jürgen Hirsch, Erkin D. Beglov, Sergey V. Konovalov i Vladimir R. Kargin. "Specific of the Recrystallization Driving Force Calculation on the early Stages of Thermomechanical Treatment of Aluminum Alloys". Materials Science Forum 1037 (6.07.2021): 273–80. http://dx.doi.org/10.4028/www.scientific.net/msf.1037.273.

Pełny tekst źródła

Streszczenie:

The article investigates the effect of the strain rate on the driving force of recrystallization during hot working of the as-cast structure. For the study, we applied previously obtained experimental data of recrystallization kinetics during this stage of thermomechanical treatment. In addition, hot laboratory rolling, followed by saltpeter bath soaking, were performed in order to obtain supplemental data on grain structure size and orientations. Grain structure size was examined by optical microscopy, and its orientation was examined by X-ray texture analysis. The studies demonstrated, that overestimated recrystallization driving force not only results in erroneous kinetics estimation, but also gives excessive number of recrystallization centers and undersized grain structure. Besides, unaccounted effect of recrystallization driving force on grain size leads to distorted predictions of texture composition. In order to avoid this, it was recommended to apply an special exponential accumulated strain dependent coefficient.

Style APA, Harvard, Vancouver, ISO itp.

34

Almasri, Moayad, Peter J. S. Foot, John W. Brown i Jacqueline A. Clipson. "Synthesis and Properties of an N-Substituted Polypyrrole with Liquid Crystalline Moieties". Polymers and Polymer Composites 26, nr 4 (maj 2018): 283–88. http://dx.doi.org/10.1177/096739111802600402.

Pełny tekst źródła

Streszczenie:

The synthesis and characterisation of two pyrrole monomers substituted at the N-position with a liquid crystal group are reported. Polymerisation of one of these compounds produced a soluble liquid crystalline semiconducting polymer. The side-chain of the polymer had a flexible spacer of nine methylene units, terminated by a mesogenic cyanobiphenyl group. The new compounds were chemically characterised and were found by hot-stage polarised optical microscopy to exhibit liquid crystal mesophases. The polymer was lightly doped p-type by exposure to iodine vapour, and its electrical conductivity was measured. The polymer synthesis and doping/dedoping processes were also briefly studied by cyclic voltammetry.

Style APA, Harvard, Vancouver, ISO itp.

35

Kalappa, Kavitha Erra, i N. Ramalakshmi. "Cytotoxic Anti-Cancer Activity of Certain Thermotropic Liquid Crystalline Poly (Ester-Amides) Containing 2, 6-Bis (Benzylidene)Cyclohexanone Moiety in the Main Chain". Journal of Drug Delivery and Therapeutics 9, nr 4-s (15.08.2019): 210–23. http://dx.doi.org/10.22270/jddt.v9i4-s.3273.

Pełny tekst źródła

Streszczenie:

Five thermotropic liquid crystalline poly(ester-amides) were synthesized by polycondensation method. The poly(ester-amides) were synthesized from varying dicarboxylic acids with a common diamine namely 4,4'-diaminobenzene and a common diol namely 2,6-bis(4-hydroxybenzylidene))cyclohexanone. For qualitative characterization, viscosity measurements and solubility data were used for these synthesized poly(ester-amides). The spectroscopic techniques such as FT-IR, 1H NMR, 13C NMR were performed to investigate the microstructural features of these synthesized poly(ester-amides). The thermal phase transition behavior of these poly(ester-amides) were studied by Differential Scanning Calorimetry (DSC) and Hot-stage Optical Polarized Microscopy (HOPM). The degree of crystallinity was assessed by X-ray diffraction (XRD) patterns. Scanning Electron Microscopic (SEM) technique was used to illustrate the morphology of these poly(ester-amides). The copolymer synthesized was subjected into in vitro anti-cancer activity studies against human breast cancer (MCF-7) cell line. Keywords: Bisbenzylidenecyclohexanone; poly(ester-amides); polycondensation; thermotropic liquid crystalline properties; cytotoxicity, anticancer.

Style APA, Harvard, Vancouver, ISO itp.

36

Huang, Guang Jie, Ling Yun Wang, Guang Sheng Huang, Fu Sheng Pan i Qing Liu. "Effect of Rolling and Annealing on the Mechanical Properties and Microstructure of AZ31 Magnesium Alloy". Materials Science Forum 546-549 (maj 2007): 379–82. http://dx.doi.org/10.4028/www.scientific.net/msf.546-549.379.

Pełny tekst źródła

Streszczenie:

Microstructural evolution and mechanical properties of the AZ31 magnesium alloy during rolling and annealing process were investigated. The sheet samples were prepared after different stages of the hot rolling, cold rolling and annealing processes. The hot rolling temperature was between 300-450C and the final thickness of the cold rolled sheets was 1.5mm. The cold rolled sheets were annealed at different annealing temperature (260-350C) for different time (10~120min). Tensile test was performed to investigate the mechanical properties of the samples obtained from different stages. With aid of the optical microscopy, scanning electron microscopy (SEM) techniques, the microstructure of the samples were characterized and the results were related to the mechanical properties. It was found the hot-rolled sheets exhibit higher ductility comparing with the cold-rolled sheets. The microstructural investigation showed that the microstructure of the hot-rolled samples was dominated by recrystallized equiaxed grains while the microstructure of the cold-rolled samples dominated by deformation twining. By applying annealing on the cold-rolled sheets, fine recrystallization grains were obtained and ductility of the samples was improved. The effects of the grain size and twining on mechanical properties of the AZ31 sheet were further discussed based on the experimental results.

Style APA, Harvard, Vancouver, ISO itp.

37

Romankiewicz, Remigiusz. "The Study of the Tensile Strength of AlSi21CuNiMg Silumin in the Final Stage of Solidification and the Initial Stage of Cooling". Journal of Casting & Materials Engineering 3, nr 3 (30.09.2019): 57–61. http://dx.doi.org/10.7494/jcme.2019.3.3.57.

Pełny tekst źródła

Streszczenie:

The paper presents the results of tensile strength tests of AlSi21CuNiMg silumin made on a test stand. Silumin was under examination in an unmodified state and after modification with AlCu19P1.4 master alloy in quantity of 0.2% in relation to the mass of the alloy. Using a scanning microscope, the surface fractures obtained from tensile tests were tested. The structure and profiles of fractures were examined using an optical microscope. Modification of the tested silumin resulted in a favorable fragmentation and regular distribution of the crystals of the primary silicon in the alloy structure, which led to an almost twofold increase in the strength of the silumin samples at the final solidification stage from 3.5 to 6.6 MPa. As a result of these changes, the resistance of silumin to hot cracks should increase, which is of great importance when casting hypereutectic silumin in a metal mould that strongly inhibits the shrinkage of the castings.

Style APA, Harvard, Vancouver, ISO itp.

38

Rahbar, Ruhollah Semnani, i Mohammad Reza Mohaddes Mojtahedi. "Influence of Hot Multistage Drawing on Structure and Mechanical Properties of Nylon 6 Multifilament Yarn". Journal of Engineered Fibers and Fabrics 6, nr 2 (czerwiec 2011): 155892501100600. http://dx.doi.org/10.1177/155892501100600202.

Pełny tekst źródła

Streszczenie:

The effect of hot multistage drawing conditions on the structure and properties of nylon 6 fibers was investigated by varying second stage draw ratio. Total draw ratio was changed from 3.3 to 5.775 to clarify the structural changes in nylon 6 fiber at a broad range of draw ratio. The structural development of the fibers was studied with FTIR spectroscopy, differential scanning calorimetry (DSC), optical microscopy, and tensile testing. A continuous drop of the γ crystalline form content is observed as a function of draw ratio, in parallel with an increased content of α crystalline phase. The γ crystalline phase vanished completely at draw ratio of 4.62. Increasing draw ratio caused an increase in birefringence and no significant change occurred in crystallinity for the drawn nylon 6 fibers. Deformation behavior of drawn nylon 6 fibers has been explained in terms of applied thermal treatment and mechanical deformations which occurred in each step of multistage drawing.

Style APA, Harvard, Vancouver, ISO itp.

39

Libera, M. "In-Situ crystallization of nano-wires and dots by electron irradiation in a field-emission TEM/STEM". Proceedings, annual meeting, Electron Microscopy Society of America 53 (13.08.1995): 242–43. http://dx.doi.org/10.1017/s0424820100137586.

Pełny tekst źródła

Streszczenie:

Specimen damage and heating by high-energy electron irradiation can be exploited to affect local specimen composition/temperature to drive phase transformations. Field-emission (FEG) sources are especially prone to inducing damage/heating, because their high brightness provides focused ~1nm FWHM/1.0nA probes. The physics of beam heating and damage are reviewed by Reimer (1,2). Heating is related to energy-loss mechanisms broadly summarized by the Bethe formula for stopping power. Radiation damage can cause atomic displacement, ionization, and bond scission. Displacement increases the point-defect concentration. Composition changes occur when displacements eject atoms from the specimen. This paper outlines first results using focused-probe irradiation in a Philips CM20 FEG TEM/STEM to locally crystallize an amorphous 80nm Ge48Te52 film. Ex-situ annealing leads to spherulitic crystallites. The crystallization kinetics have been studied by time-resolved reflectivity (3) and in-situ hot-stage optical microscopy (4). In-situ TEM annealing was done with a single-tilt hot stage. Films were floated from carbon-coated mica onto Cu grids. In-situ annealing under a parallel (low dose) beam leads to crystallization much like the ex-situ studies except that the crystallite morphology is highly anisotropic due to non-uniform film heating (5).

Style APA, Harvard, Vancouver, ISO itp.

40

Zhao, Yu Lei, Wei Min Zhang, Ji Lei Li i Jia Ling Pu. "Synthesis of Side-Chain Liquid Crystal Polymers and Preliminary Studies of the Property of Photo-Alignment". Advanced Materials Research 380 (listopad 2011): 301–5. http://dx.doi.org/10.4028/www.scientific.net/amr.380.301.

Pełny tekst źródła

Streszczenie:

Two kinds of photo-crosslinkable polymers with a coumarin-containing and cinnamate-containing side group were synthesized in this paper. The structure of the intermediates, monomers and polymers were characterized with FTIR and 1HNMR measurement. Differential scanning calorimetry (DSC), hot stage polarized optical microscopy (POM) were employed to study the phase-transition temperature, mesophase texture. UV-VIS spectrophotometer was used to survey the ultraviolet absorption performance of the polymers. The results showed that the monomer with cinnamate group showed nematic phase and smectic phase over a wide temperature range. What’s more, the ultraviolet absorption peak of the polymer with cinnamate group was at about 285 nm, and the ultraviolet absorption peak of the polymer with coumarin group was around 311.00 nm.

Style APA, Harvard, Vancouver, ISO itp.

41

Barannikova, Svetlana, Yurii F. Ivanov, Dmitriy Kosinov, Sergey Konovalov, Оksana Stolboushkina i Victor Gromov. "Plastic Deformation Localization of Low Carbon Steel: Hydrogen Effect". Advanced Materials Research 1013 (październik 2014): 77–83. http://dx.doi.org/10.4028/www.scientific.net/amr.1013.77.

Pełny tekst źródła

Streszczenie:

In the present study, the features of plastic strain localization and structure of polycrystalline low carbon steelFe-0.07%Cwere investigated after hot rolling and electrolytic hydrogen saturation. The method of double-exposure speckle photographyhave been used for identification of main types and parameters of plastic flow localization at different stages of strain hardening.Shown the effect of hydrogen on changing of defect substructure and cementite morphology by using optical and electron microscopy.

Style APA, Harvard, Vancouver, ISO itp.

42

Chitra, V., i D. Roopsingh. "Synthesis and Characterization of Certain Photoactive Liquid Crystalline Poly(ester amides) from 2,5-Pyridine Dicarboxylic Acid". Asian Journal of Chemistry 31, nr 5 (28.03.2019): 997–1001. http://dx.doi.org/10.14233/ajchem.2019.21720.

Pełny tekst źródła

Streszczenie:

A new series of four photo-crosslinkable thermotropic liquid crystalline poly(ester amides) were synthesized by direct polycondensation of 2,5-pyridine dicarboxylic acid with two different varying diols and diamines. Two diamines employed in the synthesis were 4,4′-diaminodiphenyl methane and 1,4-diaminobenzene. The arylidene diols 2,5-bis(4-hydroxy-3-methoxybenzylidene)cyclopentanone and 2,6-bis(4-hydroxy-3-methoxybenzylidene)cyclohexanone were also used. The synthesized poly(ester amides) were characterized by qualitative solubility test, FT-IR, 1H and 13C NMR spectra. The monomeric moieties were found to be well incorporated in the polymer back bone. The molecular weight of the polymer was assessed by gel permeation chromatography (GPC). The thermal phase transition behavior and liquid crystallinity of the poly(ester amides) were investigated by differential thermogravimetry (DTG) and hot stage optical polarized microscopy (HOPM), respectively. Interestingly, these poly(ester amides) in dimethylacetamide were found to possess photo-crosslinking characteristics when irradiated by UV light. These polymeric materials may find utility value in optical information storage devices.

Style APA, Harvard, Vancouver, ISO itp.

43

Kumar, Sujeet, S. J. Burns i T. N. Blanton. "Growth kinetics, phase transitions, and cracking in cholesterol gallstones". Journal of Materials Research 10, nr 1 (styczeń 1995): 216–24. http://dx.doi.org/10.1557/jmr.1995.0216.

Pełny tekst źródła

Streszczenie:

The growth kinetics of cholesterol gallstones have been studied by growing crystals from melted gallstones. The resulting microstructures are spherulitic which is essentially the same as the structures seen in natural gallstones prior to melting. The cholesterol crystals when observed in hot stage microscopy emerge from a unique nucleation center growing radially in the [001] direction with constant rate. The DSC thermograph of a natural gallstone is initially similar to that of cholesterol monohydrate. Upon melting, cholesterol monohydrate changes to anhydrous cholesterol; both forms are crystalline and exhibit polymorphic transformations. Synthetic stones grown from cholesterol were anhydrous and have a phase change at temperatures close to human body temperature. Optical microscopy established that this phase transformation cracks the spherulitic crystals perpendicular to the fast growth direction. Thermal expansion measurements demonstrate that upon heating, the low density, low temperature phase is transformed to a high density phase. This phase transformation and repeated cracking may prove to be useful in destroying natural gallstones, while suppressing this transformation and its associated cracking might aid in securing other solid cholesterol deposits within the human body.

Style APA, Harvard, Vancouver, ISO itp.

44

Noll, Andreas, i Nicole Knoer. "Crystallization Behaviour of TiO₂ Nanoparticle Reinforced Polypropylene". Materials Science Forum 636-637 (styczeń 2010): 688–96. http://dx.doi.org/10.4028/www.scientific.net/msf.636-637.688.

Pełny tekst źródła

Streszczenie:

Composites of isotactic polypropylene (iPP) with different TiO2 nanoparticle loads (0.5 vol.%, 2 vol.% and 4 vol.%) were compounded by optimized twin screw extrusion. The crystallization behaviour of these semicrystalline nanocomposites was examined by differential scanning calorimetry (DSC), scanning electron microscope (SEM) and polarized optical light microscope (POM) combined with a hot stage module to pursue in-situ the structure development. Wet chemical etching was applied to highlight morphological details like spherulites and lamellar structures for SEM observations. An obvious influence of TiO2-nanoparticles on the crystallization could be verified.

Style APA, Harvard, Vancouver, ISO itp.

45

Mohan Reddy, Goddeti Siva, Tanneru Narasimhaswamy, Jarugala Jayaramudu, Emmanuel Rotimi Sadiku, Konduru Mohana Raju i Suprakas Sinha Ray. "A New Series of Two-Ring-Based Side Chain Liquid Crystalline Polymers: Synthesis and Mesophase Characterization". Australian Journal of Chemistry 66, nr 6 (2013): 667. http://dx.doi.org/10.1071/ch13090.

Pełny tekst źródła

Streszczenie:

A new series of side chain liquid crystalline polymers containing a core, a butamethylenoxy spacer, ester groups, and terminal alkoxy groups were synthesised and their structures were confirmed. The core was constructed with two phenyl rings and an ester linking unit. All the polymers were characterised by hot-stage polarising optical microscopy, differential scanning calorimetry, variable temperature X-ray diffraction, thermogravimetric analysis, and gel permeation chromato-graphy. The polymers were found to be liquid crystalline. The nematic and smectic A (SA) phases were observed for the homologues with short-terminal chains (C2 and C6), whereas the homologues with longer chains (C8 to C12) exhibited a smectic C phase. The thermal stability of the polymers was found to be in the range of 293 to 326°C and the molecular weights of the polymers were found to vary from 6 × 103 to 1.3 × 104.

Style APA, Harvard, Vancouver, ISO itp.

46

Howe, James M. "In situ high-resolution Transmission electron microscopy of interphase boundary motion in metallic alloys". Proceedings, annual meeting, Electron Microscopy Society of America 49 (sierpień 1991): 450–51. http://dx.doi.org/10.1017/s0424820100086556.

Pełny tekst źródła

Streszczenie:

Information provided by in situ studies is often essential for understanding microstructural evolution in solids. The recent development of intermediate-voltage high-resolution transmission electron microscopes (HRTEM) with in situ heating capabilities now provides the opportunity to perform in situ high-resolution studies of interphase boundary (IPB) motion. This paper presents initial results on in situ HRTEM studies of IPB motion in metallic alloys, in particular, during growth of Q precipitates in an Al-Cu-Mg-Ag alloy and Pd3Si crystals in an amorphous Pd-Si alloy.Samples of an Al-4Cu-0.5Mg-0.5Ag (wt.%) alloy were aged for 24 hr at 250°C and electropolished in a HNO3/methanol solution; samples of an amorphous Pd80Si20 (at.%) ribbon were ion milled in a liquid-nitrogen cold-stage at 6 kV, 0.3 mA and 15° tilt. The samples were examined at 400 kV in a JEOL 4000EX microscope equipped with a UHP40X hot-stage pole piece and double-tilt holder at temperatures of 200-400°C. Images were recorded on a Sony BetaCam video cassette recorder connected to a Gatan fiber-optically coupled TV camera with an image intensifier. A 35 mm camera was used to obtain photographs directly from the TV monitor during playback of the video cassettes.

Style APA, Harvard, Vancouver, ISO itp.

47

Shanavas, A., T. Narasimhaswamy i A. Sultan Nasar. "Trimesic Acid-Based Star Mesogens with Flexible Spacer: Synthesis and Mesophase Characterization". Australian Journal of Chemistry 65, nr 10 (2012): 1426. http://dx.doi.org/10.1071/ch12258.

Pełny tekst źródła

Streszczenie:

A series of trimesic acid-based star mesogens containing an octamethylenoxy spacer and two-ring containing side arms with terminal alkoxy groups were synthesised by a divergent approach. A structurally similar mesogen containing a three-ring side arm was also synthesised. All the mesogens and intermediates were characterised thoroughly using FT-IR, 1H NMR, 13C NMR spectroscopy, and elemental analysis techniques. The mesophase characteristics were identified by hot stage optical polarising microscopy (HOPM) and differential scanning calorimetry (DSC), while X-ray was used to confirm the existence of a smectic A (SA) phase. The HOPM and DSC results revealed the presence of rich polymesomorphism in the star mesogens. The dominance of a SA phase in the series is attributed to the steric repulsion associated with steric asymmetry. The change of the side arm from two rings to three rings was found to increase the mesophase stability.

Style APA, Harvard, Vancouver, ISO itp.

48

Aryshenskii, Evgenii, Jurgen Hirsch i Sergey Konovalov. "Investigation of the Intermetallic Compounds Fragmentation Impact on the Formation of Texture during the as Cast Structure Thermomechanical Treatment of Aluminum Alloys". Metals 11, nr 3 (19.03.2021): 507. http://dx.doi.org/10.3390/met11030507.

Pełny tekst źródła

Streszczenie:

In this work, the influence of the intermetallic particle fragmentation during hot rolling of the as cast structure on the evolution of textures in aluminum alloys 8011, 5182 and 1565 was investigated. For this purpose, laboratory multi-pass rolling of the cast material was carried out. At various degrees of hot rolling deformation, the process was stopped, and the metal was quenched and sent for optical and electron microscopy to investigate the large intermetallic particles. In addition, the grain structure was studied and an X-ray analysis was carried out in order to determine the main texture components. Some of the samples were held at a temperature above the recrystallization threshold and then cooled in air; the grain structure and texture composition were also studied. In addition, the simulation of the texture evolution was carried out under various modes of rolling of aluminum alloys, taking into account the process of fragmentation of intermetallic particles. The investigation showed that intermetallic compounds with a deformation degree of 1.8, on average, decrease the particle size by 5–7 times. The large eutectic particles remaining after homogenization are drawn out in the direction of deformation and are crushed, increasing their number accordingly. Therefore, the most favorable stage for the formation of recrystallization nuclei on particles is the moment when they are already numerous and their sizes are much larger than subgrains. Simulation of hot rolling of the investigated alloys showed that considering the factor of fragmentation of intermetallic particles during hot deformation of the as-cast structure significantly increases the accuracy of the results.

Style APA, Harvard, Vancouver, ISO itp.

49

Cerda Vázquez, Perla Julieta, José Sergio Pacheco-Cedeño, Mitsuo Osvaldo Ramos-Azpeitia, Pedro Garnica-González, Vicente Garibay-Febles, Joel Moreno-Palmerin, José de Jesús Cruz-Rivera i José Luis Hernández-Rivera. "Casting and Constitutive Hot Flow Behavior of Medium-Mn Automotive Steel with Nb as Microalloying". Metals 10, nr 2 (1.02.2020): 206. http://dx.doi.org/10.3390/met10020206.

Pełny tekst źródła

Streszczenie:

A novel medium-Mn steel microstructure with 0.1 wt.% Nb was designed using Thermo-Calc and JMatPro thermodynamic simulation software. The pseudo-binary equilibrium phase diagram and time–temperature transformation (TTT) and continuous cooling transformation (CCT) diagrams were simulated in order to analyze the evolution of equilibrium phases during solidification and homogenization heat treatment. Subsequently, the steel was cast in a vacuum induction furnace with the composition selected from simulations. The specimens were heat-treated at 1200 °C and water-quenched. The results of the simulations were compared to the experimental results. The microstructure was characterized using optical microscopy (OM) and scanning electron microscopy (SEM). We found that the as-cast microstructure consisted mainly of a mixture of martensite, ferrite, and a low amount of austenite, while the microstructure in the homogenization condition corresponded to martensite and retained austenite, which was verified by X-ray diffraction tests. In order to design further production stages of the steel, the homogenized samples were subjected to hot compression testing to determine their plastic flow behavior, employing deformation rates of 0.083 and 0.83 s−1, and temperatures of 800 and 950 °C.

Style APA, Harvard, Vancouver, ISO itp.

50

Thayee Al-Janabi, Omer Y., Ahmed K. Hussein, Emaad T. Bakir Al-Tikrity, Osamah A. Hussein i Hana’a K. Salih. "Design of new Schiff base polymers containing thiadiazole rings and study of their liquid crystalline behavior". Polymers and Polymer Composites 28, nr 2 (24.07.2019): 100–111. http://dx.doi.org/10.1177/0967391119865121.

Pełny tekst źródła

Streszczenie:

New liquid crystalline thiadiazole dibenzaldehyde monomers labeled as THDB1–THDB3 were successfully synthesized by alkylation of thiadiazole’s potassium salt with 4-(bromomethyl) benzaldehyde. A number of polymers consisting of thiadiazole and azomethine coded PTDAZ1–PTDAZ5 were synthesized via condensation reaction of the presynthesized monomers THDB1–THDB3 with aromatic diamines. The chemical structures of the prepared materials were confirmed using Fourier-transform infrared spectroscopy and proton nuclear magnetic resonance techniques. The liquid crystalline behavior of the studied monomers and polymers was examined by differential scanning calorimetry and hot stage polarized optical microscopy (POM) techniques. All these compounds were found to demonstrate mesomorphic transitions belonging to smectic and nematic liquid crystals. The studied monomers exhibited fan-like texture of smectic mesophase under POM cooling investigation. Fan-like texture of smectic and nematic mesophases was observed under POM for PTDAZ1 and PTDAZ2, while PTDAZ3 and PTDAZ4 revealed clay and schlieren textures of the smectic and nematic mesophases, respectively, and nematic texture has been found for the polymer PTDAZ5.

Style APA, Harvard, Vancouver, ISO itp.

Artykuły w czasopismach na temat „Hot Stage Optical Microscopy”

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