Artigos de revistas: "Diamond diagrams"

1

Wang, Ji-Tao, Yong-Zhong Wan, David Wei Zhang, Zhi-Jie Liu e Zhong-Qiang Huang. "Calculated phase diagrams for activated low pressure diamond growth from C–H, C–O, and C–H–O systems". Journal of Materials Research 12, n.º 12 (dezembro de 1997): 3250–53. http://dx.doi.org/10.1557/jmr.1997.0426.

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Three-dimensional temperature (T)–pressure (P)–composition (X) phase diagrams of binary carbon-hydrogen (C–H) and carbon-oxygen (C–O) systems for activated low pressure diamond growth have been calculated. Based on an approximation of linear combination between C–H and C–O systems, a projective ternary carbonhydrogen-oxygen (C–H–O) phase diagram has also been obtained. There is always a diamond growth region in each of these phase diagrams. Once a supply of external activating energy stops, the diamond growth region will not exist. Nearly all of the reliable experimental data reported in the literature drop into the possible diamond growth region of the calculated projective ternary C–H–O phase diagram under the conditions of 0.01–100 kPa and above 700 K.

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Litvin, Yu A., e A. V. Spivak. "Genesis of diamonds and paragenetic inclusions under lower mantle conditions: the liquidus structure of the parental system at 26 GPa". Геохимия 64, n.º 2 (15 de março de 2019): 128–44. http://dx.doi.org/10.31857/s0016-7525642128-144.

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The patterns of the joint genesis of diamonds, and their paragenetic inclusions under lower-mantle conditions, are controlled by the liquidus melting conditions of the multicomponent diamond-forming system. The boundary compositions of this system are evident from the generalized data produced by the analytical mineralogy of paragenetic inclusions in lower-mantle diamonds. We studied the structure of the liquidus of a theoretical diamond-forming system in a physicochemical experiment with P–T parameters typical of the depths of 670–800 km. The compositions of the parental melts/solutions for diamonds and paragenetic inclusions correspond to the multicomponent system MgO–FeO–СаО–SiO2–MgCO3–FeCO3–CaCO3–Na2CO3–C. Its primary melting ёwas controlled by the peritectic phase relations at the solidus, which was revealed by experimental studies of polythermal sections of the system and their phase diagrams. Of key importance is the effect of the “stishovite paradox,” in which the peritectic reaction between the ultrabasic bridgmanite phase and melt coincides with the formation of basic oxide associations of periclase–wustite solid solutions and stishovite. The peritectic reaction of bridgmanite is a fundamental feature of the diamond-forming system, and it determines the major defining characteristics in its liquidus structure. Elements of the peritectic liquidus provide the physicochemical basis for the evolution of growth melts that yield diamonds and their paragenetic minerals. On the basis of the experimental results, we constructed a fractional diagram of the syngenesis of diamonds and inclusions. It clearly illustrates the solution–melt mechanism by which diamond genesis occurs, as well as the sequence of growth trapping of primary inclusions by diamonds under the lower-mantle conditions. The physicochemical factors of the genesis of diamonds and their primary inclusions agree: they are generalized in a compositional diagram of lower-mantle diamond-forming media, and they provide a natural basis for the genetic classification of inclusions of rock-forming and accessory minerals in diamonds.

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Nefedov, Yuriy Viktorovich, e Igor Vyacheslavovich Klepikov. "Occurrence Regularities of Nitrogen Defects in the Ural Type Crystal Diamonds from Different Regions". Key Engineering Materials 769 (abril de 2018): 201–6. http://dx.doi.org/10.4028/www.scientific.net/kem.769.201.

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The collection of the Ural, Anabar and Brazilian diamonds is studied by infrared spectrometry method. For the reconstruction of the thermal formation conditions of diamond crystals, V. Taylor’s diagrams are made with the calculated isotherms. Graphs of the ratio of B1 and B2 defects are drawn. Conclusions about the thermal conditions of the Ural diamonds formation and their possible affinity to the specific and type of indigenous sources are made.

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4

Turkevich, V. Z. "Phase Diagrams and Synthesis of Diamond". High Pressure Research 22, n.º 3-4 (janeiro de 2002): 525–29. http://dx.doi.org/10.1080/08957950212426.

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Fang, Jiaqi, Zhen Feng e Bo Cai. "DrawnNet: Offline Hand-Drawn Diagram Recognition Based on Keypoint Prediction of Aggregating Geometric Characteristics". Entropy 24, n.º 3 (19 de março de 2022): 425. http://dx.doi.org/10.3390/e24030425.

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Offline hand-drawn diagram recognition is concerned with digitizing diagrams sketched on paper or whiteboard to enable further editing. Some existing models can identify the individual objects like arrows and symbols, but they become involved in the dilemma of being unable to understand a diagram’s structure. Such a shortage may be inconvenient to digitalization or reconstruction of a diagram from its hand-drawn version. Other methods can accomplish this goal, but they live on stroke temporary information and time-consuming post-processing, which somehow hinders the practicability of these methods. Recently, Convolutional Neural Networks (CNN) have been proved that they perform the state-of-the-art across many visual tasks. In this paper, we propose DrawnNet, a unified CNN-based keypoint-based detector, for recognizing individual symbols and understanding the structure of offline hand-drawn diagrams. DrawnNet is designed upon CornerNet with extensions of two novel keypoint pooling modules which serve to extract and aggregate geometric characteristics existing in polygonal contours such as rectangle, square, and diamond within hand-drawn diagrams, and an arrow orientation prediction branch which aims to predict which direction an arrow points to through predicting arrow keypoints. We conducted wide experiments on public diagram benchmarks to evaluate our proposed method. Results show that DrawnNet achieves 2.4%, 2.3%, and 1.7% recognition rate improvements compared with the state-of-the-art methods across benchmarks of FC-A, FC-B, and FA, respectively, outperforming existing diagram recognition systems on each metric. Ablation study reveals that our proposed method can effectively enable hand-drawn diagram recognition.

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6

Wang, Ji-Tao, Yong-Zhong Wan, Zhi-Jie Liu, Hao Wang, David Wei Zhang e Zhong-Qiang Huang. "Phase diagrams for activated CVD diamond growth". Materials Letters 33, n.º 5-6 (janeiro de 1998): 311–14. http://dx.doi.org/10.1016/s0167-577x(97)00123-7.

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7

Ohtake, Naoto, Masanori Hiratsuka, Kazuhiro Kanda, Hiroki Akasaka, Masanori Tsujioka, Kenji Hirakuri, Atsushi Hirata et al. "Properties and Classification of Diamond-Like Carbon Films". Materials 14, n.º 2 (9 de janeiro de 2021): 315. http://dx.doi.org/10.3390/ma14020315.

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Diamond-like carbon (DLC) films have been extensively applied in industries owing to their excellent characteristics such as high hardness. In particular, there is a growing demand for their use as protective films for mechanical parts owing to their excellent wear resistance and low friction coefficient. DLC films have been deposited by various methods and many deviate from the DLC regions present in the ternary diagrams proposed for sp3 covalent carbon, sp2 covalent carbon, and hydrogen. Consequently, redefining the DLC region on ternary diagrams using DLC coatings for mechanical and electrical components is urgently required. Therefore, we investigate the sp3 ratio, hydrogen content, and other properties of 74 types of amorphous carbon films and present the classification of amorphous carbon films, including DLC. We measured the sp3 ratios and hydrogen content using near-edge X-ray absorption fine structure and Rutherford backscattering-elastic recoil detection analysis under unified conditions. Amorphous carbon films were widely found with nonuniform distribution. The number of carbon atoms in the sp3 covalent carbon without bonding with hydrogen and the logarithm of the hydrogen content were inversely proportional. Further, we elucidated the DLC regions on the ternary diagram, classified the amorphous carbon films, and summarized the characteristics and applications of each type of DLC.

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Ohtake, Naoto, Masanori Hiratsuka, Kazuhiro Kanda, Hiroki Akasaka, Masanori Tsujioka, Kenji Hirakuri, Atsushi Hirata et al. "Properties and Classification of Diamond-Like Carbon Films". Materials 14, n.º 2 (9 de janeiro de 2021): 315. http://dx.doi.org/10.3390/ma14020315.

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Diamond-like carbon (DLC) films have been extensively applied in industries owing to their excellent characteristics such as high hardness. In particular, there is a growing demand for their use as protective films for mechanical parts owing to their excellent wear resistance and low friction coefficient. DLC films have been deposited by various methods and many deviate from the DLC regions present in the ternary diagrams proposed for sp3 covalent carbon, sp2 covalent carbon, and hydrogen. Consequently, redefining the DLC region on ternary diagrams using DLC coatings for mechanical and electrical components is urgently required. Therefore, we investigate the sp3 ratio, hydrogen content, and other properties of 74 types of amorphous carbon films and present the classification of amorphous carbon films, including DLC. We measured the sp3 ratios and hydrogen content using near-edge X-ray absorption fine structure and Rutherford backscattering-elastic recoil detection analysis under unified conditions. Amorphous carbon films were widely found with nonuniform distribution. The number of carbon atoms in the sp3 covalent carbon without bonding with hydrogen and the logarithm of the hydrogen content were inversely proportional. Further, we elucidated the DLC regions on the ternary diagram, classified the amorphous carbon films, and summarized the characteristics and applications of each type of DLC.

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9

Ruijl, B., T. Ueda e J. A. M. Vermaseren. "The diamond rule for multi-loop Feynman diagrams". Physics Letters B 746 (junho de 2015): 347–50. http://dx.doi.org/10.1016/j.physletb.2015.05.015.

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10

Conway, Lewis J., e Andreas Hermann. "High Pressure Hydrocarbons Revisited: From van der Waals Compounds to Diamond". Geosciences 9, n.º 5 (16 de maio de 2019): 227. http://dx.doi.org/10.3390/geosciences9050227.

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Methane and other hydrocarbons are major components of the mantle regions of icy planets. Several recent computational studies have investigated the high-pressure behaviour of specific hydrocarbons. To develop a global picture of hydrocarbon stability, to identify relevant decomposition reactions, and probe eventual formation of diamond, a complete study of all hydrocarbons is needed. Using density functional theory calculations we survey here all known C-H crystal structures augmented by targeted crystal structure searches to build hydrocarbon phase diagrams in the ground state and at elevated temperatures. We find that an updated pressure-temperature phase diagram for methane is dominated at intermediate pressures by CH 4 :H 2 van der Waals inclusion compounds. We discuss the P-T phase diagram for CH and CH 2 (i.e., polystyrene and polyethylene) to illustrate that diamond formation conditions are strongly composition dependent. Finally, crystal structure searches uncover a new CH 4 (H 2 ) 2 van der Waals compound, the most hydrogen-rich hydrocarbon, stable between 170 and 220 GPa.

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11

Qiu, Tianxu, Jianwei Feng, Bo Cai, Guojiang Fan, Wei Zhang e Yong Liu. "Microstructural Evolution of Diamond-Based Composites at High Temperature and High Pressure". Materials 15, n.º 24 (8 de dezembro de 2022): 8753. http://dx.doi.org/10.3390/ma15248753.

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Improving the toughness of diamond composites has become an industrial demand. In this work, Co50Ni40Fe10 multi-element alloy was designed as binder for diamond-based composites prepared by high temperature and high pressure (HTHP). Two methods of mixing-sintering and infiltration-sintering were used to prepare diamond-based composites with different diamond contents. The phase diagrams of Co-C and Co50Ni40Fe10-C at 6 GPa were calculated by Thermo-Calc. The results show that Co50Ni40Fe10 multi-element alloy promotes the sintering of diamond powder than element Co. The transverse rupture strength (TRS) of sintered diamond with Co50Ni40Fe10 (Co50Ni40Fe10-75 vol% diamond) is higher than that of Co-Comp (Co-75 vol% diamond). The TRS of polycrystalline diamond (PCD) with Co50Ni40Fe10 alloy binder is up to 1360.3 MPa, which is 19.2% higher than Co-PCD. Compared with Co, using Co50Ni40Fe10 as binder results in a less metal residue in PCD, while the metal cluster area is smaller and the metal distribution is more uniform.

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12

Czelej, Kamil, e Piotr Śpiewak. "Hydrogen passivation of vacancies in diamond: Electronic structure and stability from ab initio calculations". MRS Advances 2, n.º 5 (2017): 309–14. http://dx.doi.org/10.1557/adv.2017.100.

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ABSTRACTPoint defects in diamond such as vacancies act as a strong donor compensation center; therefore, remarkably reduce electron conductivity of diamond-based devices. Artificial synthesis methods of n-type diamond utilize the hydrogen-containing precursors enabling its diffusion into diamond crystal and subsequent formation of hydrogen-vacancy complexes. Here we employ spin-polarized, hybrid density functional theory calculations, in order to characterize the electronic properties and stability of hydrogen-passivated vacancies in diamond. We found strong thermodynamic preference for hydrogen passivation of four vacancy-related dangling bonds. An analysis of formation energy vs Fermi level diagrams indicate, that strong donor compensation effect associated with vacancies can be entirely neutralized by hydrogen incorporation. Thus, a careful control of hydrogen partial pressure in the growth process might be crucial to improve the electron conductivity of n-type diamond.

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13

Jenness, Stuart E. "Diamond Jenness's archaeological investigations on Barter Island, Alaska". Polar Record 26, n.º 157 (abril de 1990): 91–102. http://dx.doi.org/10.1017/s003224740001113x.

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AbstractIn June and July 1914 DiamondJenness.amember of Stefansson's Canadian Arctic Expedition 1913–18, excavated 103 archaeological features in three abandoned native villages originally inhabited 400 to 550 years ago on Barter Island and nearby Arey Island, northern Alaska. His notes, diagrams, and some 3300 specimens for long remained unstudied. Recently they have been shown to provide much of the available information on the prehistoric occupation of the western Beaufort Sea coast.

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14

Liu, Zhi-Jie, David Wei Zhang, Jian-Yun Zhang, Yong-Zhong Wan e Ji-Tao Wang. "Phase diagrams for CVD diamond deposition from halogen-containing gas phase". Thin Solid Films 342, n.º 1-2 (março de 1999): 42–46. http://dx.doi.org/10.1016/s0040-6090(98)01329-7.

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15

Ristein, J., M. Riedel, L. Ley, D. Takeuchi e H. Okushi. "Band diagrams of intrinsic and p-type diamond with hydrogenated surfaces". physica status solidi (a) 199, n.º 1 (setembro de 2003): 64–70. http://dx.doi.org/10.1002/pssa.200303814.

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16

Bogdanova, L. I., Yu V. Shchapova, L. Y. Sushanek, E. A. Vasiliev e S. L. Votyakov. "Determination of the internal structural heterogeneity of natural diamond: Methodological aspects of using confocal Raman spectroscopy with polarization analysis". LITHOSPHERE (Russia) 24, n.º 2 (7 de maio de 2024): 347–63. http://dx.doi.org/10.24930/1681-9004-2024-24-2-347-363.

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Aim. To describe a technique for studying the internal structural heterogeneity of natural diamond crystals, based on confocal Raman spectroscopy with polarization analysis, including angular resolution, at high spectral (0.5–0.6 cm–1) and spatial (1 μm) resolution. Results. The parameters of the F2g vibrational mode in diamond (position, width, intensity, shape, including the Gaussian and Lorentzian contributions to the broadening) are determined by the superposition influence of a number of factors, including the type and content of structural stresses, deformations, various types of defects, as well as orientation of crystallographic axes of the crystal relative to the directions of incident and scattered rays and the directions of their electric polarization vectors. The proposed analytical technique includes: (1) analysis of the crystallographic orientation of the sample in the spectrometer coordinate system and possible misorientations of its fragments with an error of ≈8–15°; (2) visualization of the distribution of structural stresses, deformations, twins, impurity defects and their associates based on sample surface mapping by spectral parameters of the F2g vibration mode; (3) obtaining statistical characteristics of the internal structural heterogeneity of the samples based on diagrams of spectral parameter frequency with a statistically significant number (≈103): unimodality (uni-, bimodal distributions) and distribution dispersion (from ≈0.1 to ≈0.6 cm–1 for width and from ≈0.04 to ≈0.6 cm–1 for line position). The procedure was tested using two synthetic CVD diamond single crystals doped with nitrogen and boron. The possibility of typification of natural samples by statistical characteristics of internal heterogeneity is considered using the example of samples from kimberlite pipes of Yakutia and placers of the Western Cis-Urals. Conclusions. A method for determining the internal structural heterogeneity of natural diamond crystals based on confocal Raman spectroscopy with polarization analysis is proposed. The possibility of using statistical characteristics of heterogeneity as a typomorphic feature of the original diamond source is demonstrated. The proposed diagrams are promising for sample comparison and typification.

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BARBIER, FRANCK, e XABIER ARETXANDIETA. "STATE-BASED COMPOSITION IN UML 2". International Journal of Software Engineering and Knowledge Engineering 18, n.º 08 (dezembro de 2008): 987–1011. http://dx.doi.org/10.1142/s0218194008003970.

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The Composition relationship or "black diamond" in the Unified Modeling Language (UML) is recognized for a long time as a key modeling construct. While prior research works demonstrated that this modeling operator had a dubious semantics, new expectations in the field of Component-Based Software Engineering especially, lead to revisit this operator so that it supports dynamical composition, and more precisely, composition modeling expressions and implementations that safely refer to states of software components. At first, the revision of the UML Composition must rely on well-formalized static dependencies between components as, for instance, the property of lifetime dependency between compound and constituent entities. This papers offers a UML metamodel and some associated logical assertions to strengthen the Composition relationship in UML 2. Despite the presence of new diagram types dedicated to composition (i.e., Composite Structure Diagrams), the UML 2 composition model is not yet sufficiently exhaustive and formal for dealing with all cases of composition, including those relating to agent, component or service computing and modeling.

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Liu, Kang, Sen Zhang, Benjian Liu, Mingchun Xu, Zhengfeng Ren, Pengfei Qiao, Jingjing Xue et al. "Investigating the energetic band diagrams of oxygen-terminated CVD grown e6 electronic grade diamond". Carbon 169 (novembro de 2020): 440–45. http://dx.doi.org/10.1016/j.carbon.2020.07.079.

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Gavryushkin, Pavel N., Altyna Bekhtenova, Sergey S. Lobanov, Anton Shatskiy, Anna Yu Likhacheva, Dinara Sagatova, Nursultan Sagatov et al. "High-Pressure Phase Diagrams of Na2CO3 and K2CO3". Minerals 9, n.º 10 (30 de setembro de 2019): 599. http://dx.doi.org/10.3390/min9100599.

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The phase diagrams of Na 2 CO 3 and K 2 CO 3 have been determined with multianvil (MA) and diamond anvil cell (DAC) techniques. In MA experiments with heating, γ -Na 2 CO 3 is stable up to 12 GPa and above this pressure transforms to P 6 3 /mcm-phase. At 26 GPa, Na 2 CO 3 - P 6 3 /mcm transforms to the new phase with a diffraction pattern similar to that of the theoretically predicted Na 2 CO 3 - P 2 1 /m. On cold compression in DAC experiments, γ -Na 2 CO 3 is stable up to the maximum pressure reached of 25 GPa. K 2 CO 3 shows a more complex sequence of phase transitions. Unlike γ Na 2 CO 3 , γ -K 2 CO 3 has a narrow stability field. At 3 GPa, K 2 CO 3 presents in the form of the new phase, called K 2 CO 3 -III, which transforms into another new phase, K 2 CO 3 -IV, above 9 GPa. In the pressure range of 9–15 GPa, another new phase or the mixture of phases III and IV is observed. The diffraction pattern of K 2 CO 3 -IV has similarities with that of the theoretically predicted K 2 CO 3 - P 2 1 /m and most of the diffraction peaks can be indexed with this structure. Water has a dramatic effect on the phase transitions of K 2 CO 3 . Reconstruction of the diffraction pattern of γ -K 2 CO 3 is observed at pressures of 0.5–3.1 GPa if the DAC is loaded on the air.

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Hara, Keisuke, Hiromi Isobe e Akira Kyusojin. "Optimization of Cutting Edge Truncation Depth for Ultrasonically Assisted Grinding to Finish Mirror Surface". Advanced Materials Research 76-78 (junho de 2009): 88–93. http://dx.doi.org/10.4028/www.scientific.net/amr.76-78.88.

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High precision mold grinding technique to obtain mirror surface is required which realizes minimization or omission of final polishing by skilled workers. In the previous reports, ultrasonic diamond grinding experiments were carried out to confirm ultrasonic oscillation effect for die steel face grinding. Smooth and glossy surfaces were obtained successfully and little abrasive worn out was found. In the above techniques require cutting edge truncation because the cutting edge shape of a tool affects the ground surface resulting from transcription of cutting edge. This paper describes optimization techniques for the cutting edge truncation of diamond electroplated tools which are used in ultrasonically assisted grinding. Experiments were carried out to confirm truncation effects on the ground surface and grinding force. It was confirmed that roughness was proportional to inverse of thrust force. Minimum roughness in grinding conditions were estimated from the proportional diagrams. The minimum roughness shows limit of roughness on an each grinding condition.

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Liu, Zhi-Jie, David Wei Zhang, Peng-Fei Wang, Shi-Jin Ding, Jian-Yun Zhang, Ji-Tao Wang e Katharina Kohse-Hoinghaus. "Projective phase diagrams for CVD diamond growth from C–H and C–H–O systems". Thin Solid Films 368, n.º 2 (junho de 2000): 253–56. http://dx.doi.org/10.1016/s0040-6090(00)00776-8.

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Matyunin, Vyacheslav M., Artem Yu Marchenkov, Nuha Abusaif e Nikita A. Stasenko. "EVALUATION OF THE ELASTIC COMPLIANCE OF THE HARDNESS TESTER IN KINETIC INDENTATION TESTS". Industrial laboratory. Diagnostics of materials 85, n.º 4 (15 de maio de 2019): 57–63. http://dx.doi.org/10.26896/1028-6861-2019-85-4-57-63.

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When determining the mechanical properties of materials in kinetic indentation tests using indentation diagrams, careful consideration of the elastic compliance of the device, i.e., the hardness tester, is required. The determined values of the Young's modulus of the tested material substantially depend on the reliability of the method of evaluation and accounting for the elastic compliance. Therefore, verification of the test techniques based on kinetic indentation should be carried out using the materials with the known, but rather different values of the Young's modulus. Successful experience has been gained to date in the evaluating and accounting for the elastic compliance of the device upon kinetic indentation of the materials by a diamond pyramid which is reflected in the relevant standards. However, there is no way of transferring this experience to the kinetic indentation by a steel or carbide ball without additional research and experimental verification. We proposes a technique for estimating the elastic compliance of a hardness tester using a kinetic ball indentation diagram based on the G. Hertz equation for the case of elastic contact of a ball with a plane. A linear correlation has been determined between the additional elastic deformations of the device and indentation load, which is characteristic of each device and independent on the ball diameter. The obtained dependence allows for correct consideration of the elastic compliance of the device using software applications in recording and processing the ball indentation diagrams. Experiments have been carried out to determine the hardness and the Young's modulus through ball instrumented indentation of different materials (steel, aluminum alloy, magnesium alloy, and titanium alloy) using the existing and developed methods of taking into account the elastic compliance of the device. The coincidence or proximity of the values of the Young's modulus of the same material determined from the ball indentation diagrams and sample tensile tests is considered the main criterion proving the accuracy of the technique. The advantages and shortcomings of the known and proposed procedures are discussed along with practical recommendations for their applications.

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Usov, S. V., I. P. Tochilin e A. V. Zhdanov. "Industrial Application of the Diamond-Electrochemical Honing Method". Elektronnaya Obrabotka Materialov 59, n.º 4 (agosto de 2023): 54–64. http://dx.doi.org/10.52577/eom.2023.59.4.54.

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The method of diamond-electrochemical honing (DEH) is a finishing method that provides the required characteristics of the surface roughness, the distribution of the residual surface stress diagrams, which ultimately ensures the formation of a high-strength electroplated coating. This article presents studies of changes in the surface roughness, the residual stresses, and other parameters depending on the selected DEH modes for the parts made of steels 30KhGSA, 30KhN2MFA, 35KhN2MFASH, 23KhGS2MFALU, and St. 50A. The article presents the design of the instrument-khon; with the solution of the issue of the geometric characteristics of the cathode part, the insulating coating and the material of the hone tool guides. The regime support of the DEH was formed on the base of the studies whose results of are given in the article. The selected kinematic-geometric indicators of the hone-tool – a workpiece system make it possible to form the drives of the DEH equipment. The optimal composition of the DEH electrolyte was chosen with the creation of an electrolyte storage and a supply system. The article contains the results that demonstrate the effect of DEH on the reliability and durability of the parts subjected to the use of this method. The data on the technical and economic efficiency of the created industrial site of DEH are presented.

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Jésior, Jean-Claude, Roger Vuong e Henri Chanzy. "An Electron Diffraction Study on Litnerized Potato Starch". Proceedings, annual meeting, Electron Microscopy Society of America 48, n.º 1 (12 de agosto de 1990): 580–81. http://dx.doi.org/10.1017/s042482010018166x.

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Starch is arranged in a crystalline manner within its storage granules and should thus give sharp X-ray diagrams. Unfortunately most of the common starch granules have sizes between 1 and 100μm, making them too small for an X-ray study on individual grains. There is only one instance where an oriented X-ray diagram could be obtained on one sector of an individual giant starch granule. Despite their small size, starch granules are still too thick to be studied by electron diffraction with a transmission electron microscope. The only reported study on starch ultrastructure using electron diffraction on frozen hydrated material was made on small fragments. The present study has been realized on thin sectioned granules previously litnerized to improve the signal to noise ratio.Potato starch was hydrolyzed for 10 days in 2.2N HCl at 35°C, dialyzed against water until neutrality and embedded in Nanoplast. Sectioning was achieved with a commercially available low-angle “35°” diamond knife (Diatome) after a very carefull trimming and a pre-sectioning with a classical “45°” diamond knife. Sections obtained at a final sectioning angle of 42.2° (compared with the usual 55-60°) and at a nominal thickness of 900Å were collected on a Formvar-carbon coated grid. The exact location of the starch granules in their sections was recorded by optical microscopy on a Zeiss Universal polarizing microscope (Fig. 1a). After rehydration at a relative humidity of 95% for 24 hours they were mounted on a Philips cryoholder and quench frozen in liquid nitrogen before being inserted under frozen conditions in a Philips EM 400T electron microscope equipped with a Gatan anticontaminator and a Lhesa image intensifier.

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Chakoumakos, Bryan C., e John B. Parise. "Probing Phase Transitions and Magnetism in Minerals with Neutrons". Elements 17, n.º 3 (1 de junho de 2021): 181–88. http://dx.doi.org/10.2138/gselements.17.3.181.

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The development of sophisticated sample environments to control temperature, pressure, and magnetic field has grown in parallel with neutron source and instrumentation development. High-pressure apparatus, with high- and low-temperature capability, novel designs for diamond cells, and large volume presses are matched with next-generation neutron sources and moderator designs to provide unprecedented neutron beam brightness. Recent developments in sample environments are expanding the pressure–temperature space accessible to neutron scattering experiments. Researchers are using new capabilities and an increased understanding of the fundamentals of structural and magnetic transitions to explore new territories, including hydrogenous minerals (e.g., ices and hydrates) and magnetic structural phase diagrams.

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Yahyono, Khansa Aulia Arinda Putri Ari, e Nurul Hidayah. "Analysis of packaging defect on goat milk caramel candy in Etawa Agroprima". Journal of Halal Science and Research 4, n.º 1 (18 de fevereiro de 2023): 20–27. http://dx.doi.org/10.12928/jhsr.v4i1.7243.

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Goat's milk has the same benefits as cow's milk. Goat's milk contains many nutrients, especially complete protein from all kinds of essential amino acids. Etawa Agroprima is a company engaged in the processing and marketing dairy products. One of the products produced is goat's milk caramel candy. These candies are packaged using candy wrappers and diamond paper, which is covered with paper again, then put into PE plastic, sealed using a sealer, and put in a cardboard box. This packaging is intended to maintain the quality of the candy because the candy is easily runny if left open so that the caramel candy is not easily damaged. Writing this final project aims to determine the types of defects that occur in caramel candy products, the number of defective products for the entire product, and the causes of product defects—analysis of product types and defects using Pareto diagram analysis, while the cause using fishbone diagram analysis. Analysis of the data obtained on Etawa Agroprima using the two diagrams shows that the results of the Pareto diagram analysis show three types of defects, including torn packaging 75.56%, damaged packaging 13.33%, and no expiration label 11.11%. Then from the fishbone diagram analysis, it can be seen that the main factor causing defects in goat's milk caramel candy products is the packaging factor. Some root causes include manual production and packaging work, not using modern packaging equipment, contamination by physical contact, etc. Therefore, it is necessary to use automatic packaging tools.

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Zhang, Pan-Pan, Zhong-Yang Gao, Yu-Liang Xu, Chun-Yang Wang e Xiang-Mu Kong. "Phase diagrams, quantum correlations and critical phenomena of antiferromagnetic Heisenberg model on diamond-type hierarchical lattices". Quantum Science and Technology 7, n.º 2 (22 de março de 2022): 025024. http://dx.doi.org/10.1088/2058-9565/ac57f4.

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Abstract The spin-1/2 antiferromagnetic (AF) Heisenberg systems are studied on three typical diamond-type hierarchical lattices (systems A, B and C) with fractal dimensions 1.63, 2 and 2.58, respectively, and the phase diagrams, critical phenomena and quantum correlations are calculated by a combination of the equivalent transformation and real-space renormalization group methods. We find that there exist a reentrant behavior for system A and a finite temperature phase transition in the isotropic Heisenberg limit for system C (not for system B). Unlike the ferromagnetic case, the Néel temperatures of AF systems A and B are inversely proportional to ln Δ c − Δ (when Δ → Δc) and ln Δ (when Δ → 0), respectively. And we also find that there is a turning point of quantum correlation in the isotropic Heisenberg limit Δ = 0 where there is a ‘peak’ of the contour and no matter how large the size of system is, quantum correlation will change to zero in the Ising limit for the three systems. The quantum correlation decreases with the increase of lattice size L and it is almost zero when L ⩾ 30 for system A, and for systems B and C, they still exist when L is larger than that of system A. Moreover, we discuss the effects of quantum fluctuation and analyze the errors of results in the above three systems, which are induced by the noncommutativity.

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Zhang, Shao Jian, Suet To e Chi Fai Cheung. "Nonlinear Dynamics of Tool Vibration in Micro-Cutting". Key Engineering Materials 516 (junho de 2012): 645–50. http://dx.doi.org/10.4028/www.scientific.net/kem.516.645.

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This study focuses on the nonlinear dynamic characteristics of tool vibration in ultra precision diamond turning. Considering the first mode vibration of a tool, the tool is modelled as a one degree of freedom spring-mass-damper system with a developed cutting force model. Numerical simulations were carried out to anlyze the nonlinear dynamics of the system, using bifurcation diagrams, Poincaré maps, phase protraits, time histories and power spectral densities. The results indicated that the dynamic response of the tool is dominantly periodic and harmonic at its natural frequency with a little negligible chaos and its natural frequency, more than its fundamental frequency, is slightly shifted by depth of cut and cutting force.

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Yao, Yu, Dandan Sang, Liangrui Zou, Dong Zhang, Qingru Wang, Xueting Wang, Liying Wang, Jie Yin, Jianchao Fan e Qinglin Wang. "Enhanced Photoluminescence and Electrical Properties of n-Al-Doped ZnO Nanorods/p-B-Doped Diamond Heterojunction". International Journal of Molecular Sciences 23, n.º 7 (30 de março de 2022): 3831. http://dx.doi.org/10.3390/ijms23073831.

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The hydrothermal approach has been used to fabricate a heterojunction of n-aluminum-doped ZnO nanorods/p-B-doped diamond (n-Al:ZnO NRs/p-BDD). It exhibits a significant increase in photoluminescence (PL) intensity and a blue shift of the UV emission peak when compared to the n-ZnO NRs/p-BDD heterojunction. The current voltage (I-V) characteristics exhibit excellent rectifying behavior with a high rectification ratio of 838 at 5 V. The n-Al:ZnO NRs/p-BDD heterojunction shows a minimum turn-on voltage (0.27 V) and reverse leakage current (0.077 μA). The forward current of the n-Al:ZnO NRs/p-BDD heterojunction is more than 1300 times than that of the n-ZnO NRs/p-BDD heterojunction at 5 V. The ideality factor and the barrier height of the Al-doped device were found to decrease. The electrical transport behavior and carrier injection process of the n-Al:ZnO NRs/p-BDD heterojunction were analyzed through the equilibrium energy band diagrams and semiconductor theoretical models.

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Hasanzadeh, Hamid, Ehsan Mohtarami, Mohammad Ebadati, Kazem Reza Kashyzadeh e Mostafa Omidi Bidgoli. "Collapse analysis of Al 6061 alloy conical shells with circular cutouts under axial loading: experiment and simulation". Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications 236, n.º 4 (6 de janeiro de 2022): 704–14. http://dx.doi.org/10.1177/14644207211054655.

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The current research is conducted to investigate the experimental and numerical study of crushing behavior and buckling modes of thin-walled truncated conical shells with or without cutouts and discontinuities under axial loading. In this regard, Instron 8802 servohydraulic machine is used to perform the experiments. Additionally, the buckling modes, derived from the axial collapse phenomenon, are simulated with Finite Element (FE) software. The force-displacement diagrams extracted numerically are compared with experimental results. Various factors, including maximum force, energy absorption, specific energy, and failure modes of each case, are also discussed. The results indicate that the increasing cutout cause a decrease in the maximum force and energy absorption. Moreover, with cutouts reduction, the failure modes of the samples changed from the diamond asymmetric mode and single-lobe mode to multi-lobes, and with removing cutouts, the failure mode is observed to be completely symmetric.

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Okamoto, Kiyomi, Takashi Tonegawa e Tôru Sakai. "Effect of monomer-monomer interactions on the phase diagrams of the S = 1/2 distorted diamond type quantum spin chain". Journal of Physics: Conference Series 683 (5 de fevereiro de 2016): 012038. http://dx.doi.org/10.1088/1742-6596/683/1/012038.

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Ekiz, Cesur, Jozef Strečka e Michal Jaščur. "Phase diagrams of the mixed spin-1 and spin-1/2 Ising–Heisenberg model on the diamond-like decorated Bethe lattice". Journal of Magnetism and Magnetic Materials 323, n.º 5 (março de 2011): 493–98. http://dx.doi.org/10.1016/j.jmmm.2010.10.001.

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Sommer, M., e F. W. Smith. "Activity of tungsten and rhenium filaments in CH4/H2 and C2H2/H2 mixtures: Importance for diamond CVD". Journal of Materials Research 5, n.º 11 (novembro de 1990): 2433–40. http://dx.doi.org/10.1557/jmr.1990.2433.

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The resistance R, spectral emissivity ∊, and power consumption of W and Re filaments heated to 2500 °C in mixtures of CH4 or C2H2 in H2 have been measured in a series of experiments focusing on the state of the filament activity, i.e., its ability to dissociate the reactant gases. It has been found that these properties of the filaments, as well as the partial pressures of CH4 and C2H2 in the reaction chamber, depend critically on both the filament temperature and the reactant ratio, e.g., C2H2/H2. Specifically, both W and Re filaments show sharp jumps in power consumption at essentially the same temperature, signaling strong increases in filament activity and, hence, production of atomic hydrogen. These results are proposed to be due to the removal of nonreactive carbon from the surface of the filament via etching by atomic hydrogen and are consistent with the predictions of our thermodynamic model for the C–H system. Evidence for gas phase reactions is presented and the role of thermal diffusion is discussed. The emissivities of the W and Re filaments are observed to have significantly different temperature dependences which are attributed to differences in the phase diagrams for the W–C and Re–C systems. The implications of these results for hot-filament diamond CVD are discussed.

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Arifutzzaman, A., Md Abdul Maleque e D. Sujan. "The Crystallinity and Hardness Properties of Al-Cu/SiC_p New Composite Materials". Advanced Materials Research 576 (outubro de 2012): 450–53. http://dx.doi.org/10.4028/www.scientific.net/amr.576.450.

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The main aim of this paper is to investigate the crystallinity and hardness properties of Al-Cu/SiCp matrix composite (AMC) materials. The materials were prepared using a noble stir casting technique by varying the percentage of Cu in the Al-Cu matrix. Qualitative X-ray analysis has been carried out to characterize the crystallinity of the Al-Cu/SiCp as-cast composite materials. Sample was cut and shaped into 25 mm×15 mm×4 mm in dimension then polished with diamond paste. X-ray diffraction diagrams were recorded using a transmission technique with a SHIMADZU Lab X (XRD-6000) X-ray generator operating at Cu Kα1 radiation. Hardness test was conducted using Vickers hardness tester (Mitutuyo, MVK-H2). The results indicated that a significant crystal growth was occurred in the composite materials due to increase of Cu from 2 to 4 % whereas a slight improvement of crystallinity was observed when the Cu percentage was increased from 4 to 6 % in the matrix. It was also revealed from the result that a similar trend was grasped in hardness increment with the crystallinity of Al-Cu/SiCp AMCs.

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Senthilnathan, Karthikeyan, Ali Shamimi, Craig Bonsignore, Harshad Paranjape e Tom Duerig. "Effect of Prestrain on the Fatigue Life of Superelastic Nitinol". Journal of Materials Engineering and Performance 28, n.º 10 (23 de setembro de 2019): 5946–58. http://dx.doi.org/10.1007/s11665-019-04334-2.

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Abstract Three types of fatigue testing are performed to elucidate the effects of prestraining superelastic Nitinol on its subsequent fatigue lifetime: rotary bending and tension–tension testing of wire, and beam bending using diamond-shaped specimens fabricated from tubing. Results show that local plastic deformation during prestraining induces residual stresses that have a pronounced effect on fatigue performance, enhancing performance when the fatigue duty cycle is of the same sense as the prestraining (tensile prestraining followed by a tensile duty cycle, for example), and decreasing fatigue lifetime when the sense of the duty cycle is opposite to that of prestraining. This provides an avenue to increasing fatigue lifetime, but more importantly it highlights the need to fully understand the nature of the duty cycle: for example, prestraining a stent by crimping it into a delivery catheter induces favorable residual stresses with respect to subsequent pulsatile fatigue, but might accelerate fracture in other modes, such as axial or crush fatigue. Caution is also advised when trying to apply data from “constant life diagrams” derived from the literature (Ref 1, 2 for example) that may not properly reflect the strain history of the device being analyzed.

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Khademhosseini, Vahideh, Daryoosh Dideban, Mohammad Taghi Ahmadi e Hadi Heidari. "Schemes for Single Electron Transistor Based on Double Quantum Dot Islands Utilizing a Graphene Nanoscroll, Carbon Nanotube and Fullerene". Molecules 27, n.º 1 (4 de janeiro de 2022): 301. http://dx.doi.org/10.3390/molecules27010301.

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The single electron transistor (SET) is a nanoscale switching device with a simple equivalent circuit. It can work very fast as it is based on the tunneling of single electrons. Its nanostructure contains a quantum dot island whose material impacts on the device operation. Carbon allotropes such as fullerene (C60), carbon nanotubes (CNTs) and graphene nanoscrolls (GNSs) can be utilized as the quantum dot island in SETs. In this study, multiple quantum dot islands such as GNS-CNT and GNS-C60 are utilized in SET devices. The currents of two counterpart devices are modeled and analyzed. The impacts of important parameters such as temperature and applied gate voltage on the current of two SETs are investigated using proposed mathematical models. Moreover, the impacts of CNT length, fullerene diameter, GNS length, and GNS spiral length and number of turns on the SET’s current are explored. Additionally, the Coulomb blockade ranges (CB) of the two SETs are compared. The results reveal that the GNS-CNT SET has a lower Coulomb blockade range and a higher current than the GNS-C60 SET. Their charge stability diagrams indicate that the GNS-CNT SET has smaller Coulomb diamond areas, zero-current regions, and zero-conductance regions than the GNS-C60 SET.

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Yusenko, Kirill V., Saiana Khandarkhaeva, Maxim Bykov, Tymofey Fedotenko, Michael Hanfland, Alexander Sukhikh, Sergey A. Gromilov e Leonid S. Dubrovinsky. "Face-Centered Cubic Refractory Alloys Prepared from Single-Source Precursors". Materials 13, n.º 6 (20 de março de 2020): 1418. http://dx.doi.org/10.3390/ma13061418.

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Three binary fcc-structured alloys (fcc–Ir0.50Pt0.50, fcc–Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50) were prepared from [Ir(NH3)5Cl][PtCl6], [Ir(NH3)5Cl][PtBr6], [Rh(NH3)5Cl]2[PtCl6]Cl2 and [Rh(NH3)5Cl][PdCl4]·H2O, respectively, as single-source precursors. All alloys were prepared by thermal decomposition in gaseous hydrogen flow below 800 °C. Fcc–Ir0.50Pt0.50 and fcc–Rh0.50Pd0.50 correspond to miscibility gaps on binary metallic phase diagrams and can be considered as metastable alloys. Detailed comparison of [Ir(NH3)5Cl][PtCl6] and [Ir(NH3)5Cl][PtBr6] crystal structures suggests that two isoformular salts are not isostructural. In [Ir(NH3)5Cl][PtBr6], specific Br…Br interactions are responsible for a crystal structure arrangement. Room temperature compressibility of fcc–Ir0.50Pt0.50, fcc–Rh0.66Pt0.33 and fcc–Rh0.50Pd0.50 has been investigated up to 50 GPa in diamond anvil cells. All investigated fcc-structured binary alloys are stable under compression. Atomic volumes and bulk moduli show good agreement with ideal solutions model. For fcc–Ir0.50Pt0.50, V0/Z = 14.597(6) Å3·atom−1, B0 = 321(6) GPa and B0’ = 6(1); for fcc–Rh0.66Pt0.33, V0/Z = 14.211(3) Å3·atom−1, B0 =259(1) GPa and B0’ = 6.66(9) and for fcc–Rh0.50Pd0.50, V0/Z = 14.18(2) Å3·atom−1, B0 =223(4) GPa and B0’ = 5.0(3).

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Monday Eze, Charles Okunbor e Umoke Chukwudum. "Studies in object-oriented programming backbone implementations". Global Journal of Engineering and Technology Advances 8, n.º 3 (30 de setembro de 2021): 020–31. http://dx.doi.org/10.30574/gjeta.2021.8.3.0119.

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This work is a combination of conceptual and hands on based study aimed at laying a foundation for practical Object-Oriented software construction. First it presents a conceptual study of a number of backbone concepts of modern Object-Oriented Programming (OOP) languages. Secondly, it attempts to demonstrate real-life implementations of these concepts using Python Programming Language. This work touches on practical issues on Class and Object Creation, especially on the syntax and creation, and demystifies the subject matter using a simple table of rules. The OOP concept of Inheritance was studied, with focus on the three major types of inheritance. The self-argument, and constructors were studied, with focus on the three constructors - default, parameterized, and non-parameterized constructors. A brief discussion, and pictorial illustration was also made on the disparity between normal mathematical functions and OOP method calls. Further areas of studies are the concept of overriding between the parent and child class, as well as the OOP puzzle commonly known as Diamond Problem, including code segment and diagrammatic illustration of Python-based solutions. There are a number of other back-bone concepts in OOP not covered in this study, such as Encapsulation, Abstraction, Meta-Programming, among others, which will form areas of focus in future studies. Effort was made to enhance the overall presentation through practical illustrations using source codes, annotated diagrams, and discussions. It is hoped that this work will be very useful to researchers and other practitioners in Object Oriented implementations.

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Zhang, Yi, e Xiaoyan Yu. "Spectroscopy and Trace-Element Characteristics of Emeralds from Kamakanga, Zambia". Crystals 13, n.º 11 (20 de novembro de 2023): 1605. http://dx.doi.org/10.3390/cryst13111605.

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Currently, Zambia is the second largest source of emeralds, after Colombia. In this study, emerald samples from the Zambian Kamakanga deposit were examined by UV-Vis-NIR, Miro-FTIR, Diamond ViewTM, and LA-ICP-MS. Representative UV-Vis-NIR spectra showed a distinct Fe3+ absorption peak, and the Fe-related absorption band was much stronger than that of the Cr-related absorption band. The infrared spectra showed that the absorption of type II H2O was much stronger than that of type I H2O. The results of LA-ICP-MS indicated that darker green, green, lighter green, and bluish-green emeralds had a clear separation of Cr/V (Cr/V > 15 for darker green, 10 < Cr/V < 15 for green, and Cr/V < 10 for lighter green and bluish green). In color zoning emerald, the contents of Cr, Sc, V, and Fe gradually increased with the intensity of the green color, while the opposite occurred for Cs. Cr is the main chromogenic element in Kamakanga emeralds. Additionally, Zambian Kamakanga emeralds contain high contents of total alkali metals (avg. 17,592 ppmw), Cs (avg. 1331 ppmw), Fe (avg. 8556 ppmw), Li (avg. 485 ppmw), Li + Cs (avg. 1816 ppmw), and Ga/Fe < 0.0025. Therefore, combined Fe versus Ga, Li versus Cs binary diagrams and K, Rb, and the Li + Cs ternary plot can distinguish Zambian emeralds from other important emerald origins.

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Abell, P. I., J. McClory, H. E. Hendry e K. L. Wheatley. "Stratigraphic variations in carbon and oxygen isotopes in the dolostone of the Carswell Formation (Proterozoic) of northern Saskatchewan". Canadian Journal of Earth Sciences 26, n.º 11 (1 de novembro de 1989): 2318–26. http://dx.doi.org/10.1139/e89-197.

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Petrographic and stable isotopic analyses of stromatolitic sediments deposited in nearshore environments provides us with some of the best information available on ancient environments. Diamond drill hole CAR 58 penetrated 110 m of sediments in the lowermost part of the Proterozoic (probably Helikian age) Carswell Formation of northern Saskatchewan and gave us such an opportunity. The rocks are mainly dolostone and include, in descending order of abundance, cyanobacterial laminites, stromatolites, dolomicrites, dolorudites, breccias, and oolites. Stromatolites and Cyanobacterial laminites increase in abundance up-section, and deposition is interpreted as having taken place in conditions of increasingly restricted water circulation through time. The carbon isotope ratios vary from about −0.5 to −1.5‰ (Pee Dee Belemnite (PDB)) in the section except near the base where they assume values near −2.5‰. The oxygen isotope ratios (vs. PDB) increase from about −9.3‰ at the base to −7‰ at the top, with anomolously high values, more positive than −7‰, at two positions in the sequence. Original depositional structures and textures are still visible in most of the rocks, but gypsum has been replaced by dolomite, there has been some silicification, and original features have been obliterated by dolomite rhombs in a few samples. The upward trend to less-negative values of the oxygen isotope ratios is interpreted in terms of changing depositional environment involving a deepening but more protected basin, with increased evaporational concentration of the heavier isotope. Scatter diagrams of carbon and oxygen isotope ratios place the Carswell Formation dolomites close to the mainstream of other Proterozoic stromatolites but indicating some evaporative alterations during deposition.

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Sobolev, V. V., O. S. Kovrov, M. M. Nalisko, N. V. Bilan e O. A. Tereshkova. "Compound physical and mechanical effects stimulating metastable diamond formation". Naukovyi Visnyk Natsionalnoho Hirnychoho Universytetu, n.º 4 (2021): 47–55. http://dx.doi.org/10.33271/nvngu/2021-4/047.

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Purpose. To synthesize diamond polycrystals in a thermodynamically stable region, and to grow up a single crystal shell under conditions of thermodynamic metastability. To investigate some physical properties and features of the internal structure for synthesized single crystals for the development of new models and hypotheses regarding the issue of diamond genesis. Methodology. Experimental studies using shock-wave effects on a metal alloy containing non-diamond carbon. Methods of infrared and ultraviolet spectroscopy, X-ray phase analysis, electron paramagnetic resonance, isotope analysis, differential thermal analysis, electron microscopy, and others are used. The synthesis of nanocrystalline diamond particles as nuclei for growing single crystals is carried out by the shock-wave method using profiled shock waves. Findings. A complex of physicochemical methods for studying the grown diamond monocrystals has been carried out. The reasons for the discrete growth of diamond and the retention of the central inclusion (a polycrystalline diamond of shock-wave origin) in the process of growth have been established and analyzed. It is shown that the discreteness of diamond formation is characteristic only for thermodynamically metastable conditions. The results of the experiments give grounds to make an assumption about the metastable growth, including of diamonds from primary deposits. Originality. The hypothesis has been developed concerning the origin of diamond nanoparticles in interstellar carbon clouds which refer exclusively to central polycrystalline inclusions in a monocrystal diamond shell. The hypothesis eliminates the scientific contradiction that arises in all cases when attempts are made to interpret the natural discreteness of diamond formation based on the regularities of the graphite-diamond state diagram. Possible causes of discrete diamond formation in nature and the scenario of the formation of diamond nanocrystals in an interstellar cloud of atomic carbon have been considered. Practical value. The value of the experimental research results refers to the development of a non-energy-intensive technology for the growing large diamond monocrystals at temperatures of 5001400 K, and pressures of 105107 Pa.

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Kwok, Tsz Chun, Chi Fai Cheung, Suet To e Wing Bun Lee. "A Framework of a Surface Generation Model in Fast Tool Servo (FTS) Machining of Optical Microstructures". Key Engineering Materials 364-366 (dezembro de 2007): 1274–79. http://dx.doi.org/10.4028/www.scientific.net/kem.364-366.1274.

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In this paper, a framework of surface generation model in the fast tool servo (FTS) machining of optical microstructures will be described. The integrated model is totally composed of a tool path generator (TPG), a surface topography model (STM) and an optimization model (OM). To develop the tool path generator, two parts should be involved. The first part is the tool path generated based on cutting conditions such as the feed rate and spindle speed, the geometry of optical microstructures, and diamond tool geometry. Another part is the synchronized motion generated by the tool actuation of the FTS at a bandwidth higher than the rotational frequency of the spindle. The surface topography model will be generated based on the TPG and used to predict the technological aspects of FTS machining. It takes into the account the kinematic and dynamic characteristics of the cutting process. The former includes the tool path generated by the tool path generator. The later includes the relative vibration between the tool and the workpiece caused by the axial error motion of the spindle as well as the synchronized motion of the FTS system. The optimization model will be undertaken by an iterative algorithm, which will be developed based on the TPG and STM. The OM will be expected to output the verified tool path, the suggested optimum cutting conditions, and the diagrams with predicted cutting performance characteristic and process parameters being investigated. Eventually, the successful development of this surface generation model can contribute for the knowledge of ultra-precision machining with FTS and the further development of the performance of the machining system.

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Minami, Hiroaki. "Diamond principles in Cichoń’s diagram". Archive for Mathematical Logic 44, n.º 4 (11 de novembro de 2004): 513–26. http://dx.doi.org/10.1007/s00153-004-0269-4.

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Robertson, J., e M. J. Rutter. "Band diagram of diamond and diamond-like carbon surfaces". Diamond and Related Materials 7, n.º 2-5 (fevereiro de 1998): 620–25. http://dx.doi.org/10.1016/s0925-9635(97)00257-4.

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Kirill Olegovich, SOKOLOV. "Development of a model of a ground-penetrating radar section of a frozen rock massif with a crack". NEWS of the Ural State Mining University, n.º 2 (15 de junho de 2021): 134–39. http://dx.doi.org/10.21440/2307-2091-2021-2-134-139.

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Revelance of the work. The presence of cracks significantly affects the physical and mechanical properties of rocks, which should be taken into account when planning mining operations and building mining facilities. In the conditions of the spread of permafrost rocks, characteristic of northeastern Russia, the study of fracturing is possible by the GPR method, which is used to assess the structure of rock massifs in placer deposits. The criteria for detecting cracks based on the features of wave georadar fields are currently known, and the main problem that prevents the full use of the georadar method for studying cracks in subsurface layers of rocks is the labour-consuming nature of processing and interpreting data from georadar measurements. Purpose of the work – to determine the patterns of cracks occurrence in frozen rocks in GPR wave fields. Methodology of the work. Based on the results of longstanding field work at the developed areas of alluvial diamond deposits in the Anabar region of the Republic of Sakha (Yakutia), the main elements of the radarogram structure were determined and presented in the form of a single formula. The developed formula is implemented in programs in the SCM Matlab and the results of its execution are compared with the results of modeling in the gprMax system. Results of the work and the scope of their application. The resultant formula describes the main elements of GPR radarograms quite correctly, which confirmed their comparison with the obtained model data. The correlation coefficient between the obtained matrices (Matlab and gprMax) without the low-amplitude values of multiple reflections was 0.91, which shows the identity of the structure of GPR wave fields. Conclusions. The studies carried out have confirmed the possibility of a mathematical description of the ground penetrating radar wave field obtained by sounding a mass of frozen rocks with a crack. The high correlation coefficient showed the adequacy of the developed radarogram model, which will be finalized taking into account the directional diagrams of existing georadars.

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Duffy, Thomas, Jue Wang, Federica Coppari, Raymond Smith, Jon Eggert e Gilbert Collins. "Laser-Based Dynamic Compression of Solids to Ultrahigh Pressures". Acta Crystallographica Section A Foundations and Advances 70, a1 (5 de agosto de 2014): C396. http://dx.doi.org/10.1107/s205327331409603x.

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Laser-based dynamic compression provides new opportunities to study the structures and properties of materials to ultrahigh pressure conditions. In this technique, high-powered laser beams are used to ablate a sample surface and by reaction a compression wave is generated and propagate through the sample. By controlling the shape and duration of the laser pulse, either shock or ramp (shockless) compression can be produced. Diagnostics include velocity interferometry (from which the stress-density response of the material can be determined) and x-ray diffraction from which structural information is obtained. Magnesium oxide is a fundamental ionic solid which has been extensively examined at high pressures. Theoretical studies predict a change in MgO from a rocksalt (B1) crystal structure to a cesium chloride (B2) structure at pressures of about 400–600 GPa but diamond anvil cell experiments have not been able to reach these pressures. Here we present dynamic X-ray diffraction measurements of ramp-compressed magnesium oxide. We show that a solid–solid phase transition, consistent with a transformation to the B2 structure occurs near 600 GPa. On further compression, this structure remains stable to 900 GPa. Our results provide an experimental benchmark to the equations of state and transition pressure of magnesium oxide, and may help constrain interior properties of super-Earth extrasolar planets. We have also examined the high-pressure behavior of molybdenum under both shock and ramp loading. The melting curves and high-pressure phase diagrams of transition metals have been controversial, and Mo is an excellent test case for resolving these discrepancies. We have conducted shock compression experiments on Mo with an X-ray diffraction diagnostic to address previous claims of high-pressure phase transitions and to determine the location of the Hugoniot melting point. We have also carried out ramp compression experiments to test predictions of phase transitions in Mo at ultrahigh pressures and low temperatures.

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Pidvysotskyi, V. T., N. M. Ostafychuk e S. I. Bashinsky. "PLACER DEPOSITS OF DIAMONDS AND THEIR FORMATION CONDITIONS". Geological Journal, n.º 1 (29 de março de 2023): 17–38. http://dx.doi.org/10.30836/igs.1025-6814.2023.1.273683.

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This article reviews information from published papers and studies by the authors about placer diamond deposits. Original data were obtained in result of field and laboratory-analytical work carried out in various countries of Africa and South America. The main types of placer diamond deposits – fluvial, fluvioglacial, eolian, and man-made – have been considered and characterized. The main attention is given to fluvial continental placers, which are the most diverse, well-studied and have the greatest industrial importance. Primary, secondary and mixed deposits are distinguished according to the method of feeding; short, moderate and long transport deposits – according to the distance of the diamond-bearing material movement. It is noted that although the short transport placers (deluvial-proluvial and beds of short watercourses) have not industrial value, they are very informative for the searching for root sources. It is important to reliably diagnose these deposits by lithological-facies and mineralogical features during prospecting works. The concepts about the conditions for the formation of diamond placers in various landscape and geological conditions are developed and clarified. Alluvial-proluvial-lacustrine and proluvial-lacustrine types of placers studied in Yakutia and Brazil are characterized in detail. Their characteristic feature is that their productive strata, being re-deposited products of crustal weathering, themselves underwent a hypergenic change at the place of occurrence, which significantly masks the primary conditions of formation. Continental alluvial redeposition and long transport placers, as well as marine, yield the most high-quality expensive diamonds, the average value of which can reach $300–400 per carat. Often, such placers are formed due to the erosion of ancient Proterozoic placers, which belong to the category of fossils. The article summarizes the genetic and morphological types of diamond placers in the form of a principle diagram of the distribution of sedimentary reservoirs of kimberlite minerals. The landscape-dynamic zones of sedimentation are highlighted. A classification scheme of sedimentary reservoirs containing diamond placers has been developed. Continental, transitional and marine environments are distinguished, with further detalization of sedimentation environments – peneplain, alluvial-lacustrine accumulative plain, alluvial-deltaic plain and shelf zones of sea basins. It is shown that the formation of valley placers, their internal structure, thickness, granulometric composition and diamond content of alluvium are influenced by the dynamic phases of the formation of annual valleys. Visualization of the mutual relationship of different morpho-genetic types of placer diamond deposits is given.

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Mehdy, Malik Ashter, Mariagrazia Graziano e Gianluca Piccinini. "Simulation and Modeling of Silicon Based Single Electron Transistor". International Journal of Electrical and Computer Engineering (IJECE) 8, n.º 2 (1 de abril de 2018): 900. http://dx.doi.org/10.11591/ijece.v8i2.pp900-907.

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<p>In this work, we simulated and modeled silicon quantum dot based single electron transistor (SET). We simulated the device using non-equilibrium Green’s function (NEGF) formalism in transport direction coupled with Schrodinger equation in transverse directions. The characteristics of SET such as Coulomb blockade and Coulomb diamonds were observed. We also present a new efficient model to calculate the current voltage (IV) characteristics of the SET. The IV characteristic achieved from the model are very similar to those from simulations both in shape and magnitude. The proposed model is capable of reproducing the Coulomb diamond diagram in good agreement with the simulations. The model, which is based on transmission spectrum, is simple, efficient and provides insights on the physics of the device. The transmission spectrum at equilibrium is achieved from simulations and given as input to the model. The model then calculates the evolved transmission spectra at non-equilibrium conditions and evaluates the current using Landauers formula.</p>

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Fang, Shuai, Zhenghao Cai, Yongkui Wang, Zhiyun Lu, Chao Fang, Zhandong Zhao, Hongan Ma, Liangchao Chen e Xiaopeng Jia. "Growth and characterization of diamond single crystals grown in the Fe–S–C system by the temperature gradient method". CrystEngComm 23, n.º 10 (2021): 2063–70. http://dx.doi.org/10.1039/d0ce01548b.

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Kocherahinski, Yu A., e O. G. Kulik. "Equilibrium phase diagrams and manufacture of synthetic diamonds". Powder Metallurgy and Metal Ceramics 35, n.º 7-8 (julho de 1996): 470–83. http://dx.doi.org/10.1007/bf01329241.

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