Sort by:
Publication Type:
Open access:
Publication Date:
Periodicals:
Search results
Online since: November 2015
Authors: Alexandr Ojegov, Vladislav Rusnac, Dorin Guzgan, Pavel Topala, Vitalie Besliu
The number and the size of the conical asperities on the sample depend on the irregularities presented on the surfaces of both electrodes and on their areas, and don’t depend on the thickness and the volume of the electrodes.
Analysis on the lateral surface of the Taylor type cone has shown that in the process of solidification and constituting of solid material grains some additional nanometer-scale asperities are crystallized on their surface.
Increasing the number of electrical discharges leads to initial conical meniscus extraction, followed by the intensive oxidation of their surfaces below.
The current variation in a singular discharge impulse is manifold, which explain the increase of number of canals and conical asperities formation.
Analysis on the lateral surface of the Taylor type cone has shown that in the process of solidification and constituting of solid material grains some additional nanometer-scale asperities are crystallized on their surface.
Increasing the number of electrical discharges leads to initial conical meniscus extraction, followed by the intensive oxidation of their surfaces below.
The current variation in a singular discharge impulse is manifold, which explain the increase of number of canals and conical asperities formation.
Online since: April 2012
Authors: Zong Shou Lin, Essossinam Beguedou, Hua Dong Shi
After 3h later, the Ca2+ and Al3+ of within the GGBFS was gradually dissolved in the cement paste and response with it, The reaction generated a large number of hydration products making the cement paste gradually lost their mobility [4] .
2.2 The effect of polycarboxylate superplasticizer on the setting time
Fig. 3 describes the effect of the superplasticizer content on the setting time.
When adding admixtures into the cement, the chain anionic groups (such as-COO-, -SO3--) of Superplasticizer molecular chain reactive with the Ca2+ of the cement hydration products occur to complex, thereby reducing the alkalinity of the slurry. it affected the crystal morphology of ettringite, made ettringite of grain refinement.
At the hydration 3d of the 0%, the PG surface was surrounded by a large number of ettringite and a small amount of CSH gel, the ettringite morphology is 1 ~ 2μm slender needle, CSH gel number is small, the paste has lots of gap.
When adding admixtures into the cement, the chain anionic groups (such as-COO-, -SO3--) of Superplasticizer molecular chain reactive with the Ca2+ of the cement hydration products occur to complex, thereby reducing the alkalinity of the slurry. it affected the crystal morphology of ettringite, made ettringite of grain refinement.
At the hydration 3d of the 0%, the PG surface was surrounded by a large number of ettringite and a small amount of CSH gel, the ettringite morphology is 1 ~ 2μm slender needle, CSH gel number is small, the paste has lots of gap.
Online since: May 2014
Authors: Gerardo Antonio Rosas Trejo, J. Luis López-Miranda, M.A. Espinosa-Medina, Rodrigo Alonso Esparza Muñoz, J.R. Romero-Romero
(2)
The ball-milling process increases the reacting species diffusion through the formation of various crystalline defects and the increment of the grain surface.
Thus for example, in FeAl2 intermetallic the O/Al ratio intensities increases with milling time, indicating that an increase in the number of phases associated with oxide and hydroxide oxygen was obtained.
Another parameter that can help to understand why the FeAl3 reacts with water more efficiently than FeAl2 corresponds to the number of Al-Al bonds.
Major physical adsorption in the FeAl3 intermetallic can be attributed to the presence of high number of Al-Al non-polar groups in comparison of FeAl2.
Thus for example, in FeAl2 intermetallic the O/Al ratio intensities increases with milling time, indicating that an increase in the number of phases associated with oxide and hydroxide oxygen was obtained.
Another parameter that can help to understand why the FeAl3 reacts with water more efficiently than FeAl2 corresponds to the number of Al-Al bonds.
Major physical adsorption in the FeAl3 intermetallic can be attributed to the presence of high number of Al-Al non-polar groups in comparison of FeAl2.
Online since: September 2003
Authors: Yuan Li, Xi Peng Xu
Metal
powders were blended together with diamond grains for 40 min in an ∞ shape rotary mixer.
It is clear that both compressive strength and impact strength decrease with the increasing box number.
The number of diamond crystals with different working conditions on fracture segment surfaces as well as worn segment surfaces were counted through an optical microscope (XTL-1) and the total 24 segments on the sawblade were counted for an average.
At the same time, a small number of diamonds were broken on the fracture surface (Fig.5c), clearly showing a strong metallurgical bonding between the metal matrix and the coated diamond.
It is clear that both compressive strength and impact strength decrease with the increasing box number.
The number of diamond crystals with different working conditions on fracture segment surfaces as well as worn segment surfaces were counted through an optical microscope (XTL-1) and the total 24 segments on the sawblade were counted for an average.
At the same time, a small number of diamonds were broken on the fracture surface (Fig.5c), clearly showing a strong metallurgical bonding between the metal matrix and the coated diamond.
Online since: January 2014
Authors: Roman S. Laptev, Yurii Bordulev, Georgy V. Garanin, Viktor N. Kudiiarov, Andrey M. Lider
However some papers [4-7] have shown that hydrogen not only interacts with existing defects but also induces formation of a large number of new defects.
The average lifetime is independent of the number of artificially created components and restrictions [22].
In addition growth of long-lived component intensity I2 indicates formation of a large number of new vacancy type defects.
Islamgaliev, Positron-Lifetime Investigation of Thermal Stability of Ultra-Fine Grained Nickel, Phys. stat. sol.
The average lifetime is independent of the number of artificially created components and restrictions [22].
In addition growth of long-lived component intensity I2 indicates formation of a large number of new vacancy type defects.
Islamgaliev, Positron-Lifetime Investigation of Thermal Stability of Ultra-Fine Grained Nickel, Phys. stat. sol.
Online since: March 2016
Authors: Jian Bin Zhang, Hiroshi Yamagata, Jiu Xin Chen, Cong Xu, Wen Long Xiao, Mao Wen Liu, Chao Li Ma
(1)
Where ASi represents the area and n is the number of measured eutectic Si particles.
There are a number of explanations for this phenomenon.
A large number of fine dimples without visual porosities are observed in SD alloy, as shown in Fig. 6(b).
Akiba, Modeling the effects of cooling rate, hydrogen content, grain refiner and modifier on microporosity formation in Al A356 alloys.
There are a number of explanations for this phenomenon.
A large number of fine dimples without visual porosities are observed in SD alloy, as shown in Fig. 6(b).
Akiba, Modeling the effects of cooling rate, hydrogen content, grain refiner and modifier on microporosity formation in Al A356 alloys.
Online since: February 2013
Authors: Li Jian
At present, there are a large number of experts and scholars of various disciplines who are actively committed to the development of this subject in the world.
1 The research status of intelligent material structure
Once the intelligent material structure concept is put forward, it causes the United States, Japan and Europe and other developed countries attach importance to, and invested heavily to set up a special institution to carry out the research in this aspect.Among them, the United States will locate this intelligent structure as one of the key technologies in this century.In 1984 the United States army research bureau the intelligent rotor aircraft research to raise funds for developed can adaptive reduce rotor blade vibration and distortion of the structure.Then, in the United States defense department FY92 - FY96 plan, under the support of the us army and navy research bureau of scientific research of intelligent materials research gave more aid, the broader research.The
(2)Piezoelectric element In intelligent structure, often used for acoustic emission signal, stress wave and pressure measurement of piezoelectric materials can be divided into two categories: piezoelectric ceramic and piezoelectric polymer.The characteristics of the piezoelectric material is have a wide frequency response range, high control precision, and can be processed into various forms of sensor, easy to miniaturization and integration, can be used as a sensing element and drive element.The latest achievements of piezoelectric materials including fine grain polymer ceramics, big dependent variable (1. 7%) single crystal piezoelectric materials, piezoelectric fiber and piezoelectric composite materials, their common advantage is a great drive strain and strong designability
Different sensing element with different sensing properties, therefore, need to related sensing element mechanics - optical - electrical and coupling effect in-depth analysis, explore new combined sensor element new principle; The new type of optical fiber, laser, piezoelectric sensor principle and technology; The high performance, multifunction surface acoustic wave sensors; The distributed and quasi distributed sensing, sensor network and multi-sensor reuse principle and methods; Establish strain/temperature composite sensing principle and technology; Research new acceleration, velocity, displacement and deformation, crack, damage sensor technology; The sensor number and position optimization design, and in different environment sensing element and function of the network effect of modeling and simulation, in order to achieve the optimization of sensor and sensor network the purpose of comprehensive performance. 2. 2 Intelligent drive technology Drive technology (including drive element
Expected in years will appear a number of application of defense equipment and civil facilities which related intelligent structure.
(2)Piezoelectric element In intelligent structure, often used for acoustic emission signal, stress wave and pressure measurement of piezoelectric materials can be divided into two categories: piezoelectric ceramic and piezoelectric polymer.The characteristics of the piezoelectric material is have a wide frequency response range, high control precision, and can be processed into various forms of sensor, easy to miniaturization and integration, can be used as a sensing element and drive element.The latest achievements of piezoelectric materials including fine grain polymer ceramics, big dependent variable (1. 7%) single crystal piezoelectric materials, piezoelectric fiber and piezoelectric composite materials, their common advantage is a great drive strain and strong designability
Different sensing element with different sensing properties, therefore, need to related sensing element mechanics - optical - electrical and coupling effect in-depth analysis, explore new combined sensor element new principle; The new type of optical fiber, laser, piezoelectric sensor principle and technology; The high performance, multifunction surface acoustic wave sensors; The distributed and quasi distributed sensing, sensor network and multi-sensor reuse principle and methods; Establish strain/temperature composite sensing principle and technology; Research new acceleration, velocity, displacement and deformation, crack, damage sensor technology; The sensor number and position optimization design, and in different environment sensing element and function of the network effect of modeling and simulation, in order to achieve the optimization of sensor and sensor network the purpose of comprehensive performance. 2. 2 Intelligent drive technology Drive technology (including drive element
Expected in years will appear a number of application of defense equipment and civil facilities which related intelligent structure.
Online since: July 2020
Authors: Pei Yao Li, Guo Jun Song, Zheng Gu, Li Wang, Shi Hai Zhao
The obtained strands were grained and vigorously dried at 80 °C in an oven.
Figure 5: The mechanism of three polyethylene molecular structure to form submicroscopic morphology composite From figure 5 we could see that three kinds of polyethylene were added into the same organic montmorillonite, during the polyethylene molecules and montmorillonite intercalation composite process, due to the existence of a large number of branched LDPE molecular chains, the higher degree of branching and the longer branched chains, there were only very small part of the LDPE molecular chains into the organic layers of montmorillonite, MMT spacing did not chang during this process, the external shear force could not open the montmorillonite layer force, so the final form of the conventional micron LDPE/OMMT composites were shown in the drawings.
While the HDPE molecular chains had smaller and shorter branched chains, so early in the intercalation, there were a large number of molecular chains into the layers, so the interacting force between the layers of montmorillonite was weakened.
Acknowledgments This work was supported by [the financial support from the NSFC ] under Grant [Number:51503111].
Figure 5: The mechanism of three polyethylene molecular structure to form submicroscopic morphology composite From figure 5 we could see that three kinds of polyethylene were added into the same organic montmorillonite, during the polyethylene molecules and montmorillonite intercalation composite process, due to the existence of a large number of branched LDPE molecular chains, the higher degree of branching and the longer branched chains, there were only very small part of the LDPE molecular chains into the organic layers of montmorillonite, MMT spacing did not chang during this process, the external shear force could not open the montmorillonite layer force, so the final form of the conventional micron LDPE/OMMT composites were shown in the drawings.
While the HDPE molecular chains had smaller and shorter branched chains, so early in the intercalation, there were a large number of molecular chains into the layers, so the interacting force between the layers of montmorillonite was weakened.
Acknowledgments This work was supported by [the financial support from the NSFC ] under Grant [Number:51503111].
Online since: January 2021
Authors: Qun Bo Fan, Hong Yu, Yu Zhou, Xin Jie Zhu, Yu Gao
First, special samples are required in many cases, such as diffusion couples of multiple alloys [5], and thin film samples prepared by magnetron sputtering technique [6], which requires high technology and cost; the second is that alloy systems with multipe principal elements studied are relatively simple, and some methods were used to establish the relationship between composition and performance, such as CALPHAD (CALculation of PHAse Diagrams) [7, 8], requiring a large amount of data, but the number of elements analyzed is small.
Some high-throughput tests combining nanoindentation tests with EPMA technology to test alloys have proven to be efficient, and a large number of compositions and performance data can be obtained just by testing a small number of materials [5, 8].
It can be seen that the microstructure of the titanium alloy used in this test consists of two phases, α phase and β phase, and is a typical equiaxed structure with a grain size of about 5 μm.
Some high-throughput tests combining nanoindentation tests with EPMA technology to test alloys have proven to be efficient, and a large number of compositions and performance data can be obtained just by testing a small number of materials [5, 8].
It can be seen that the microstructure of the titanium alloy used in this test consists of two phases, α phase and β phase, and is a typical equiaxed structure with a grain size of about 5 μm.
Online since: February 2014
Authors: Pipat Bhudwannachai, Stuart Barnes, Aishah Najiah Dahnel
As the number of the drill’s rotation per unit time increased, the frequency of the scratching action and repeated abrasive damage caused by the hard carbon fibres to the cutting tool also increased per unit time.
The damage and delamination at the exit of the drilled hole is often seen to be the most critical problem since it is the most affected region in drilling CFC due to the strength of the layers becoming weak as the number of layers to be drilled decreases.
Higher cutting speed and feed rate are usually deployed when time and production rate are critical in order to machine the CFCs so that a higher number of parts can be machined within a short time.
However, the tool was able to maintain its hardness and strength when it was pre-cooled and operated at cutting temperature much below 0˚C due to the sustainment and stability of the binder particles and grains within its structure [16], [18].
The damage and delamination at the exit of the drilled hole is often seen to be the most critical problem since it is the most affected region in drilling CFC due to the strength of the layers becoming weak as the number of layers to be drilled decreases.
Higher cutting speed and feed rate are usually deployed when time and production rate are critical in order to machine the CFCs so that a higher number of parts can be machined within a short time.
However, the tool was able to maintain its hardness and strength when it was pre-cooled and operated at cutting temperature much below 0˚C due to the sustainment and stability of the binder particles and grains within its structure [16], [18].