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Online since: December 2011
Authors: Yu Xian Guo, Jie Wang, Peng Shou Xu, Wen Sheng Yan
crystallinity caused by the evolution of grain size.
(1) Where P is the circular polarization degree of photons, θ is the glancing angle (50° in this experiment), and nh is the 3d hole occupation number of the specific atom.
As films become thicker and the grain size of film are growing up, the alloy films change from amorphous phase to crystalline phase and the crystallinity becomes better.
According to previous literatures, we should point out that, the 3d hole numbers of ferromagnetic atoms are possibly changeable for different film depth near interface, and play a crucial role in the size of spin moment.
Ryan et al [21] have studied Co/Ge system, and found that the average number of 3d electrons for Co decreases from 7.51 to 6.88 with decreasing thickness.
(1) Where P is the circular polarization degree of photons, θ is the glancing angle (50° in this experiment), and nh is the 3d hole occupation number of the specific atom.
As films become thicker and the grain size of film are growing up, the alloy films change from amorphous phase to crystalline phase and the crystallinity becomes better.
According to previous literatures, we should point out that, the 3d hole numbers of ferromagnetic atoms are possibly changeable for different film depth near interface, and play a crucial role in the size of spin moment.
Ryan et al [21] have studied Co/Ge system, and found that the average number of 3d electrons for Co decreases from 7.51 to 6.88 with decreasing thickness.
Online since: February 2022
Authors: M.V. Kostina, Sarkis Muradyan, Ludmila Rigina, V.S. Kostina, Viktor M. Timokhin
Non-magnetic and wear resistance is additionally required for a number of applications.
Moreover, their number and ratio should ultimately ensure the presence of all the above-mentioned functional properties of the resulting foundry austenite.
Nitrogen content in these steels is significantly higher than that in a number of grades of nitrogen-containing austenitic casting steels used in Europe and the USA.
The size of the crystallites (grains) of cast steel (in the absence of plastic deformation and recrystallization) is very large, as can be seen from photographs of the macrostructure - Figure. 1.
And after annealing at 1200 °C and quenching, it is not prone to intergranular corrosion due to the absence of particles of excessive phases at grain boundaries and other structural elements of cast metal.
Moreover, their number and ratio should ultimately ensure the presence of all the above-mentioned functional properties of the resulting foundry austenite.
Nitrogen content in these steels is significantly higher than that in a number of grades of nitrogen-containing austenitic casting steels used in Europe and the USA.
The size of the crystallites (grains) of cast steel (in the absence of plastic deformation and recrystallization) is very large, as can be seen from photographs of the macrostructure - Figure. 1.
And after annealing at 1200 °C and quenching, it is not prone to intergranular corrosion due to the absence of particles of excessive phases at grain boundaries and other structural elements of cast metal.
Online since: November 2023
Authors: Vishwakarma Jaydeep, Kausik Chattopadhyay, N.C. Santhi Srinivas
The number of cycles to fatigue failure (Nf) was found to be decreased with increase in build orientations for the AB samples. 0o AB sample showed best fatigue life among all the tested conditions.
Similarly, after heat treatment, the number of cycles to failure (Nf) was found to be decreased with increase in build orientation.
After heat treatment, number of cycle for fatigue failure improved significantly in AB additive samples.
The effects of heat treatment on the investigated AM components are ascribed to the formation of precipitates in the martensite matrix as well as the modification of other microstructural characteristics, i.e., phase volume fraction, grain size, and morphology [4].
Due to the coarse and equiaxed grains, as-received CM samples had the lowest tensile strength of all the samples tested.
Similarly, after heat treatment, the number of cycles to failure (Nf) was found to be decreased with increase in build orientation.
After heat treatment, number of cycle for fatigue failure improved significantly in AB additive samples.
The effects of heat treatment on the investigated AM components are ascribed to the formation of precipitates in the martensite matrix as well as the modification of other microstructural characteristics, i.e., phase volume fraction, grain size, and morphology [4].
Due to the coarse and equiaxed grains, as-received CM samples had the lowest tensile strength of all the samples tested.
Online since: August 2015
Authors: John Dear, Jian Guo Lin, Mohamed Mohamed, Zhusheng Shi, Trevor Dean
Several factors affect the FLC including sheet thickness [5], temperature [6], strain rate and grain size [7] and strain hardening exponent [8].
In this damage model, expression of the three unvarying functions of the stress allows to represent two different damage mechanisms: grain boundary damage and ductility damage.
The numbers at the top of Fig. 2b are the geometry numbers corresponding to those in Fig. 1b, covering strain ratios from pure tensile to equibiaxial conditions.
(a) (b) 1 5 3 4 6 2 Fig. 2 (a) Test-pieces after isothermal tensile test at 250°C with a strain rate of 0.1 s-1, and (b) Test-pieces after isothermal FLC at 250°C and forming rate of 75 mm s-1, the numbers at the top are the geometry numbers corresponding to Fig. 1b, from left to right: tensile to equibiaxial conditions [10].
In this damage model, expression of the three unvarying functions of the stress allows to represent two different damage mechanisms: grain boundary damage and ductility damage.
The numbers at the top of Fig. 2b are the geometry numbers corresponding to those in Fig. 1b, covering strain ratios from pure tensile to equibiaxial conditions.
(a) (b) 1 5 3 4 6 2 Fig. 2 (a) Test-pieces after isothermal tensile test at 250°C with a strain rate of 0.1 s-1, and (b) Test-pieces after isothermal FLC at 250°C and forming rate of 75 mm s-1, the numbers at the top are the geometry numbers corresponding to Fig. 1b, from left to right: tensile to equibiaxial conditions [10].
Online since: September 2011
Authors: Hong Xiu Du, Yi Xiao Qin, Wei Zhang, Xiao Yu Hao, Ning Zhang
However, at present, the insufficiency of HPC widespread exist, such as the poor anti-cracking performance, high brittleness and low toughness, the durability and long service life of concrete structures was serious influence [1-3]. "5.12" wenchuan earthquake, a large number of serious damage of concrete structures also illustrate this point.
Raw material of HPC include Ordinary Portland cement P.O 42.5, the chemical compositions and physical properties of cement are listed in Table 1, river sand with a fineness modulus of 2.6 as the fine aggregate, limestone gravel with a 25 mm maximum in size and grain grade 5~25 mm as the coarse aggregate, parameters of aggregate for concrete are listed in Table 2, the material parameters of microsilica and ground granulated blast furnace slag (S95) as themineral admixture are listed in Table 3 and Table 4, superplasticizer (HS-AF) was based on naphthalene sulfonates complying with GB8076-2008, polypropylene short fibers added in the tests were four lengths of 5mm, 8mm, 15mm and 19mm, and a diameter 33 micron, main technical parameters of polypropylene fiber are listed in Table 5, mixing water was tap water.
Table 1 Chemical composition and parameters of ordinary Portland cement SiO2 [%] Al2O3 [%] CaO [%] MgO [%] Fe2O3 [%] K2O [%] Na2O [%] Surface area [m2/kg] Loss on Ignition Stability Compressive strength[MPa] Tensile strength[MPa] 3d 28d 3d 28d 20.7 6.16 64.0 1.82 4.41 1.2 0.2 350 1.5 Qualified 18.6 46.5 3.8 7.2 Table 2 Parameters of aggregate for concrete Index Apparent density [kg/m3] Bulk density [kg/m3] Material finer than 75µm [%] Clay lump Elongated flaky particle [%] Grain gradation Fineness modulus Index of crushing [%] River sand 2680 1580 0.33 0.05 - Qualified 2.6 - Croshed stone 2715 1630 0.30 0.10 2 Qualified - 6 Table 3 Material parameters of microsilica SiO2 [%] K2O [%] Na2O [%] PH Loss on Ignition [%] Water content [%] Surface area [m2/kg] Bulk density [kg/m3] 88.63 1.32 0.52 7.78 1.80 0.41 18000 350-450 Table 4 Material parameters of ground granulated blast furnace slag SiO2 [%] Al2O3 [%] CaO [%] MgO [%] MnO [%] Loss on Ignition [%] Water
Specimen Numbers: PP0 - represent concrete, PP + digital + lowercase letters -- represent mixing polypropylene fiber concrete, such as PP8a, representing concrete mixed of polypropylene fiber with a length of 8mm and 0.5 kg/m³.
Table 7 Compressive strength and Splitting tensile strength test results of HPC Specimen number Compressive strength [MPa] Splitting tensile strength [MPa] Specimen number Compressive strength [MPa] Splitting tensile strength [MPa] ppc0 68.5 5.09 pp5a 65.8 5.03 pp15a 70.3 5.33 pp5b 61.6 5.18 pp15b 68 5.85 pp5c 68.3 5.79 pp15c 68.9 5.99 pp5d 66.6 5.79 pp15d 69.6 6.03 pp5e 67.6 6.11 pp15e 69.9 6.37 pp5f 57.4 5.16 pp15f 55.1 5.38 pp8a 68.5 5.13 pp19a 72 5.54 pp8b 68.1 5.77 pp19b 67.7 5.95 pp8c 69.9 5.97 pp19c 66.7 6.01 pp8d 69.6 5.99 pp19d 66.2 6.07 pp8e 66.9 6.12 pp19e 60.1 6.38 pp8f 53.4 5.25 pp19f 43.4 5.47 Compressive strength.
Raw material of HPC include Ordinary Portland cement P.O 42.5, the chemical compositions and physical properties of cement are listed in Table 1, river sand with a fineness modulus of 2.6 as the fine aggregate, limestone gravel with a 25 mm maximum in size and grain grade 5~25 mm as the coarse aggregate, parameters of aggregate for concrete are listed in Table 2, the material parameters of microsilica and ground granulated blast furnace slag (S95) as themineral admixture are listed in Table 3 and Table 4, superplasticizer (HS-AF) was based on naphthalene sulfonates complying with GB8076-2008, polypropylene short fibers added in the tests were four lengths of 5mm, 8mm, 15mm and 19mm, and a diameter 33 micron, main technical parameters of polypropylene fiber are listed in Table 5, mixing water was tap water.
Table 1 Chemical composition and parameters of ordinary Portland cement SiO2 [%] Al2O3 [%] CaO [%] MgO [%] Fe2O3 [%] K2O [%] Na2O [%] Surface area [m2/kg] Loss on Ignition Stability Compressive strength[MPa] Tensile strength[MPa] 3d 28d 3d 28d 20.7 6.16 64.0 1.82 4.41 1.2 0.2 350 1.5 Qualified 18.6 46.5 3.8 7.2 Table 2 Parameters of aggregate for concrete Index Apparent density [kg/m3] Bulk density [kg/m3] Material finer than 75µm [%] Clay lump Elongated flaky particle [%] Grain gradation Fineness modulus Index of crushing [%] River sand 2680 1580 0.33 0.05 - Qualified 2.6 - Croshed stone 2715 1630 0.30 0.10 2 Qualified - 6 Table 3 Material parameters of microsilica SiO2 [%] K2O [%] Na2O [%] PH Loss on Ignition [%] Water content [%] Surface area [m2/kg] Bulk density [kg/m3] 88.63 1.32 0.52 7.78 1.80 0.41 18000 350-450 Table 4 Material parameters of ground granulated blast furnace slag SiO2 [%] Al2O3 [%] CaO [%] MgO [%] MnO [%] Loss on Ignition [%] Water
Specimen Numbers: PP0 - represent concrete, PP + digital + lowercase letters -- represent mixing polypropylene fiber concrete, such as PP8a, representing concrete mixed of polypropylene fiber with a length of 8mm and 0.5 kg/m³.
Table 7 Compressive strength and Splitting tensile strength test results of HPC Specimen number Compressive strength [MPa] Splitting tensile strength [MPa] Specimen number Compressive strength [MPa] Splitting tensile strength [MPa] ppc0 68.5 5.09 pp5a 65.8 5.03 pp15a 70.3 5.33 pp5b 61.6 5.18 pp15b 68 5.85 pp5c 68.3 5.79 pp15c 68.9 5.99 pp5d 66.6 5.79 pp15d 69.6 6.03 pp5e 67.6 6.11 pp15e 69.9 6.37 pp5f 57.4 5.16 pp15f 55.1 5.38 pp8a 68.5 5.13 pp19a 72 5.54 pp8b 68.1 5.77 pp19b 67.7 5.95 pp8c 69.9 5.97 pp19c 66.7 6.01 pp8d 69.6 5.99 pp19d 66.2 6.07 pp8e 66.9 6.12 pp19e 60.1 6.38 pp8f 53.4 5.25 pp19f 43.4 5.47 Compressive strength.
Online since: December 2013
Authors: Yu Lu Yang, Hua Shu Yang, Xin Long Peng, Xue Peng Wang, Ying Ju Pu, Yi Wang, Bi Chang Fu
Landslide accumulation is mainly made up of stone fragments and sandy loam, and contains a number of deadwoods of which the surface have been carbon blacked , especially on the left bank.
The composition of fragment stone is mainly full and strong weathering feldspar-quartz medium grained fine sandstone with the color of yellow-brown, a little of which is green gray.
The sandstone consists of hard green gray and yellow-brown feldspar-quartz fine grained sandstone, and local contains more black carbon blocks.
The average unit grouting amount of this segment is 205 kg/m, largely in line with the law that with the increase of hole spacing sequence and hole number, grouting amount is decreasing.
Seen from the injection rate, the average injection rate of this area with sequence number from A to C is increasing and value is larger (hole A is 407.3 kg/m, hole C is 489.2 kg/m).
The composition of fragment stone is mainly full and strong weathering feldspar-quartz medium grained fine sandstone with the color of yellow-brown, a little of which is green gray.
The sandstone consists of hard green gray and yellow-brown feldspar-quartz fine grained sandstone, and local contains more black carbon blocks.
The average unit grouting amount of this segment is 205 kg/m, largely in line with the law that with the increase of hole spacing sequence and hole number, grouting amount is decreasing.
Seen from the injection rate, the average injection rate of this area with sequence number from A to C is increasing and value is larger (hole A is 407.3 kg/m, hole C is 489.2 kg/m).
Online since: August 2014
Authors: Fan Tao Kong, Shi Wei Xu, Zhe Min Li, Jian Hua Zhang
After consulting agricultural experts’ advices, 11 categories of agricultural products were determined as agricultural products object for collection, such as grain, oilseed, sugar, vegetable, fruit, meat, egg, milk, aquatic product, cotton and flax.
Table 1 is computer coding of grain, which is presented as an example to show part of computer coding of agricultural product market information.
From the classification of agricultural products, Broad category, Category, Subcategory, Group, Brand class and product name of 6 layers are Grain, Cereals, Rice, Paddy, Indica paddy, Early indica paddy, respectively.
Android (Google Corporation, USA) and IOS (Apple Inc., USA) are popular operating systems for Smart phone, which is stable, simple operation, running fast, and can also provide sufficient memory to store large number of data[25].
Spatial-temporal changes in grain production, consumption and driving mechanism in China.
Table 1 is computer coding of grain, which is presented as an example to show part of computer coding of agricultural product market information.
From the classification of agricultural products, Broad category, Category, Subcategory, Group, Brand class and product name of 6 layers are Grain, Cereals, Rice, Paddy, Indica paddy, Early indica paddy, respectively.
Android (Google Corporation, USA) and IOS (Apple Inc., USA) are popular operating systems for Smart phone, which is stable, simple operation, running fast, and can also provide sufficient memory to store large number of data[25].
Spatial-temporal changes in grain production, consumption and driving mechanism in China.
Online since: April 2018
Authors: André Dubois, Mirentxu Dubar, Laurent Dubar
Friction coefficient vs number of produced parts, PVD-CVD TiN coated tools from [29] (a), carbide tungsten extrusion tools from [30] (b)
Concerning the study of G30 carbide tungsten, die used for the forward extrusion of steel parts have been studied after the manufacturing of 0, 100000, 150000 and 220000 parts.
Surface analyses have shown that wear of tungsten tools operates in three main steps: WC grains are subjected to plastic strain and crack propagation (surface damage), then WC grains are removed from the tool surface (abrasive wear) and finally steel torn develops from the workpiece is transferred to the empty spaces between WC grains (adhesive wear) (Fig. 16-17).
Mechanical analyses performed on the tools have highlighted that the coefficient of friction was increasing almost linearly with the number of produced parts (Fig. 15b) Fig. 16.
Tungsten carbide surface damage, grain plasticity (top), adhesive wear (middle), WC grain fracture (bottom) Tribology of cold rolling: lubricant formulation surface defects, from experiment to numerical prediction.
Experimental observations aim to identify the kind of surface defect that occurs (galling, scratch, grain debonding, etc.).
Surface analyses have shown that wear of tungsten tools operates in three main steps: WC grains are subjected to plastic strain and crack propagation (surface damage), then WC grains are removed from the tool surface (abrasive wear) and finally steel torn develops from the workpiece is transferred to the empty spaces between WC grains (adhesive wear) (Fig. 16-17).
Mechanical analyses performed on the tools have highlighted that the coefficient of friction was increasing almost linearly with the number of produced parts (Fig. 15b) Fig. 16.
Tungsten carbide surface damage, grain plasticity (top), adhesive wear (middle), WC grain fracture (bottom) Tribology of cold rolling: lubricant formulation surface defects, from experiment to numerical prediction.
Experimental observations aim to identify the kind of surface defect that occurs (galling, scratch, grain debonding, etc.).
Online since: April 2010
Authors: Y.L. Hsu, C.H. Lee, S.M. Chiu, Y.C. Sung, K.Y. Yang, C.W. Chu
From the angle view of the AFM
image, the ZrOx coating shows the smallest and most uniform grain size.
The CrWNx coating had the same surface morphology while some deviations in grain size appeared.
Each cone-like structure comprised many nano-size grains.
The surface OH group density of the film increases with increasing the number of NBOs [19].
Indicating CrOx coatings had more the number of NBOs as well as surface OH group density than ZrOx coatings.
The CrWNx coating had the same surface morphology while some deviations in grain size appeared.
Each cone-like structure comprised many nano-size grains.
The surface OH group density of the film increases with increasing the number of NBOs [19].
Indicating CrOx coatings had more the number of NBOs as well as surface OH group density than ZrOx coatings.
Online since: November 2013
Authors: Larysa Khomenkova, Xavier Portier, Abdelilah Slaoui, Fabrice Gourbilleau
It was considered that the number of HfO2-rich (SiO2-rich) layers formed in the silicate film with known chemical composition depends only on the film thickness and does not vary with annealing temperature [27].
Along with this, the number of HfO2-rich/SiO2-rich stacks in the film is controlled by its chemical composition.
Although the presence of some defects inside this IL cannot be ruled out, one can assume that the main contribution to the C-V loop originates from the HfO2-rich phase and the formation of HfO2 crystallite grains.
Furthermore, one can expect that a pronounced crystallization of HfO2 grains observed for the samples annealed at TA=1100°C (Fig.1d) will result in a larger memory window.
High annealing temperature (>1000°C) leads to the formation of pure HfO2 tetragonal grains surrounded by SiOx host.
Along with this, the number of HfO2-rich/SiO2-rich stacks in the film is controlled by its chemical composition.
Although the presence of some defects inside this IL cannot be ruled out, one can assume that the main contribution to the C-V loop originates from the HfO2-rich phase and the formation of HfO2 crystallite grains.
Furthermore, one can expect that a pronounced crystallization of HfO2 grains observed for the samples annealed at TA=1100°C (Fig.1d) will result in a larger memory window.
High annealing temperature (>1000°C) leads to the formation of pure HfO2 tetragonal grains surrounded by SiOx host.