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Online since: January 2020
Authors: Tatyana V. Mal’tseva, Anna V. Levina, Ekaterina K. Skobelina
A successful solution of this problem requires not only consideration of the existing experience of using corrosion-resistant steels but also clarification of a number of important theoretical and practical questions that have not received detailed coverage to date.
As the aging temperature of the hardened steel increases, a significant growth of the particles of the intermetallic phase is observed (Fig. 1, e, f), their number becomes smaller and the particle acquires a clear shape in the form of distorted cuboids (Fig. 1, f).
In austenite, there is a large number of microtwins, which means that the shear strain initiates local fine-scale twinning.
The effect of high shear deformations under P = 5Gpa and 8GPa, followed by aging at 500 ° C, 1 hour on the phase composition and hardness of steel Initial processing P, the value of the applied pressure [GPa] Number of revolutions HV0,05 Phase composition [%] BCC lattice BCC lattice Quenching from 1000 °С 5 0 405 74 26 5 600 82 18 8 0 505 78 22 5 950 ~100 Conclusions 1.
Ringer, Strength, grain refinement and solute nanostructures of an Al–Mg– Si alloy (AA6060) processed by high-pressure torsion, Acta Materialia, 63 (2014) 169-179
As the aging temperature of the hardened steel increases, a significant growth of the particles of the intermetallic phase is observed (Fig. 1, e, f), their number becomes smaller and the particle acquires a clear shape in the form of distorted cuboids (Fig. 1, f).
In austenite, there is a large number of microtwins, which means that the shear strain initiates local fine-scale twinning.
The effect of high shear deformations under P = 5Gpa and 8GPa, followed by aging at 500 ° C, 1 hour on the phase composition and hardness of steel Initial processing P, the value of the applied pressure [GPa] Number of revolutions HV0,05 Phase composition [%] BCC lattice BCC lattice Quenching from 1000 °С 5 0 405 74 26 5 600 82 18 8 0 505 78 22 5 950 ~100 Conclusions 1.
Ringer, Strength, grain refinement and solute nanostructures of an Al–Mg– Si alloy (AA6060) processed by high-pressure torsion, Acta Materialia, 63 (2014) 169-179
Online since: June 2007
Authors: Nobusuke Hattori, Shinichi Nishida, Wen Xian Sun, Mian Zhang
This
hardens the metal because the grains elongated.
Table 5 lists the fatigue limit σw, the ratio of the fatigue limit increase (σ*w%), the stress concentration factor, the residual stress and Vickers hardness number.
The precipitates with a certain size and number are the most effective for obstructing the movement of dislocation and for producing the maximum strengthening and hardness.
However, the numbers of crack initiation for them is different.
On the whole, the number of the cracks trends toward increasing with increase of compressive residual stress.
Table 5 lists the fatigue limit σw, the ratio of the fatigue limit increase (σ*w%), the stress concentration factor, the residual stress and Vickers hardness number.
The precipitates with a certain size and number are the most effective for obstructing the movement of dislocation and for producing the maximum strengthening and hardness.
However, the numbers of crack initiation for them is different.
On the whole, the number of the cracks trends toward increasing with increase of compressive residual stress.
Online since: April 2015
Authors: Naoya Tada, Ya Fei Hu
Since various pairs of films and substrates exist, a number of researches have been done and published.
Akogwu et al. measured the electric resistance of gold thin film on poly-di-methyl-siloxane (PDMS) substrate during monotonic and cyclic loadings, and found that the resistance change was caused by the residual stress and grain boundary cracking on the film [3].
While no cracks were introduced in gold thin film for tension and cooling analyses, 4 to 39 cracks were introduced at equal distance for cracking analyses to evaluate the effect of the number of cracks on the stress and strain of gold thin film.
The number of cracks were 4, 9, 19, and 39, and the thickness of gold thin film s was fixed at 500 [nm].
The results for four cases (the number of cracks are 4, 9, 19, and 39) are shown.
Akogwu et al. measured the electric resistance of gold thin film on poly-di-methyl-siloxane (PDMS) substrate during monotonic and cyclic loadings, and found that the resistance change was caused by the residual stress and grain boundary cracking on the film [3].
While no cracks were introduced in gold thin film for tension and cooling analyses, 4 to 39 cracks were introduced at equal distance for cracking analyses to evaluate the effect of the number of cracks on the stress and strain of gold thin film.
The number of cracks were 4, 9, 19, and 39, and the thickness of gold thin film s was fixed at 500 [nm].
The results for four cases (the number of cracks are 4, 9, 19, and 39) are shown.
Online since: September 2003
Authors: N.S. Savkina, V.V. Ratnikov, A.Yu. Rogachev, V.B. Shuman, Alexander A. Lebedev
The
number of features such as an amorphization and the existence of big pores near the epitaxial layer
concomitant this method is discussed.
Introduction Commercialization of SiC semiconductor devices is still limited by quality of SiC crystals containing a great number of structural defects (dislocations, grain boundaries, blocks, etc.).
In addition, establishing the fundamental aspects of PSC formation is complicated by the fact that SiC contains a much greater number of structural defects compared with Si, and there is no way of avoiding their influence on the obtained results.
Knowing of the porous layer thickness h (determined with an electron microscope), porosity p (found by gravimetry), and def, the volume of a single pore and the number of pores per 1 cm2 of the PSC surface can be readily calculated.
Thus, raising the substrate doping level leads to formation of a much greater number of pores with smaller diameter.
Introduction Commercialization of SiC semiconductor devices is still limited by quality of SiC crystals containing a great number of structural defects (dislocations, grain boundaries, blocks, etc.).
In addition, establishing the fundamental aspects of PSC formation is complicated by the fact that SiC contains a much greater number of structural defects compared with Si, and there is no way of avoiding their influence on the obtained results.
Knowing of the porous layer thickness h (determined with an electron microscope), porosity p (found by gravimetry), and def, the volume of a single pore and the number of pores per 1 cm2 of the PSC surface can be readily calculated.
Thus, raising the substrate doping level leads to formation of a much greater number of pores with smaller diameter.
Online since: April 2015
Authors: V.I. Shymanski, S.K. Pavlov, V.V. Uglov, G.E. Remnev
There are a number of papers showing advantages of the HPIB impact compared with other types of treatment [5-7].
The second mode of the treatment implied the relatively low ion current density (30 A/cm2) but the pulse number (n) was increased up to 100 and 500.
The alloying of the titanium samples with chromium atoms also occurs in the case of exposure to the HPIB with the ion current density of 30 A/cm2 at a large number of pulses.
In this case, by increasing the number of pulses from 100 to 500 there is an increase of chromium concentration from 4.4 to 7.8 at. %.
In this case dissolution of carbon into the lattice of the solid solution is less energetically favorable and carbon seems segregates in the grain boundary area, while reducing the dimensions themselves of the crystallites of the solid solution.
The second mode of the treatment implied the relatively low ion current density (30 A/cm2) but the pulse number (n) was increased up to 100 and 500.
The alloying of the titanium samples with chromium atoms also occurs in the case of exposure to the HPIB with the ion current density of 30 A/cm2 at a large number of pulses.
In this case, by increasing the number of pulses from 100 to 500 there is an increase of chromium concentration from 4.4 to 7.8 at. %.
In this case dissolution of carbon into the lattice of the solid solution is less energetically favorable and carbon seems segregates in the grain boundary area, while reducing the dimensions themselves of the crystallites of the solid solution.
Online since: January 2014
Authors: Jing Lv, Jing Miao Wang
In addition to a large number of city diseases are exposed out,the country has also gradually appeared all sorts of problems in the process of rapid urbanization,such as ecological condition has destroyed,widespread lack of public infrastructure,the rural traditional culture is gradually dying,etc.This article from the perspective of urban and rural planning analyzes the living environment of rural people in Changchun area which in central status of the big agricultural province Jilin by the status of rural living environment assessment to find out the problems existing in the countryside and propose improvement measures for the problem.
Table.1 Population structure of Changchun Residents population (person ) Households (unit) The number per household (person /unit ) Age structure Agricultural population (10,000 persons)/ The percentage of the provincial agricultural population Land area (sq.km)/proportion of the province Changchun city 7677089 2329737 3.08 0-14 years 15-64 years Over 65 years 416.75 32.7% 20604 11% 12% 79% 8.05% Jilin province 27462297 9001598 2.94 11.99% 79.63% 8.38% 1273.4 100% 187400 100% Economic development.
Also uses a large number of residential wood windows and doors, windows are single.
The cultural landscape.Fewer minorities, minority population accounts for less than 4% of the total population in Changchun, the long-term effects of assimilation by the Han Chinese, ethnic characteristics are not obvious, rural cultural landscape is mainly reflected in the small number of landscape architecture, landscape and road landscape courtyard.
The village itself lagging infrastructure construction and management, low processing a large number of garbage, livestock manure, straw and other waste also destroyed the village environment and it getting worse.
Table.1 Population structure of Changchun Residents population (person ) Households (unit) The number per household (person /unit ) Age structure Agricultural population (10,000 persons)/ The percentage of the provincial agricultural population Land area (sq.km)/proportion of the province Changchun city 7677089 2329737 3.08 0-14 years 15-64 years Over 65 years 416.75 32.7% 20604 11% 12% 79% 8.05% Jilin province 27462297 9001598 2.94 11.99% 79.63% 8.38% 1273.4 100% 187400 100% Economic development.
Also uses a large number of residential wood windows and doors, windows are single.
The cultural landscape.Fewer minorities, minority population accounts for less than 4% of the total population in Changchun, the long-term effects of assimilation by the Han Chinese, ethnic characteristics are not obvious, rural cultural landscape is mainly reflected in the small number of landscape architecture, landscape and road landscape courtyard.
The village itself lagging infrastructure construction and management, low processing a large number of garbage, livestock manure, straw and other waste also destroyed the village environment and it getting worse.
Online since: June 2010
Authors: Qing Yuan Zhou, Jian Jian Luo, Qing Chao Liu
Number:
08AJY003.
Typically, the famous American sociologist , modernization issue research experts alex inkeles' in the late 1960s around social and economical aspects of modern society forward ten indexes and the index of the standard is : per capita GNP is more than $3,000 , Agricultural output value of GDP ratio below 12 % , Services output value of the proportion of GDP more than 45% , The proportion of labor force non-agriculture is more than 70% , More than 80% of the population proportion of literacy , In proportion as young students school-age 10-15% , Every doctor service in the number of people under 1000 people, The average life expectancy is more than 70 years old, Infant natural mortality rates below 3% , The proportion of urban population is more than 50%, the natural growth rate of people below 1%.
Table 1 the evaluation index system first-order indexes secondary indexes standard value social and economic development level (A) Personnel per capita electricity consumption in the primary industry (A1) 1500 The non-agricultural population proportion (A2) 5 The specific gravity of Industrial added value in GDP (A3) 2 The agricultural investment level(B) The cultivatedareas per hectare of mechanical total power (B1) 15 The proportion in effective irrigated area(B2) 90 Penetration rate of three stations in rural areas (B3) 90 The proportion of serve jobholder in total employees (B4) 5 The comprehensive output level of agricultural (C) The sown area of grain yield (C1) 5000 Each rural agricultural Labour force create gross output value of agricultural(C2) 10000 Per capita meat production (C3) 200 The commodity rate of agricultural and sideline products (C4) 90 The living standards of famers(D) Rural per
Here, if some index of actual value or critical value is o or negative number, we should make it adding a proper number, so that it can be change into positive number, it can be dimensionless process.
In this paper we let each number add 1 and then go on dimensionless process. 4.3Calculating the weight of each index.
Typically, the famous American sociologist , modernization issue research experts alex inkeles' in the late 1960s around social and economical aspects of modern society forward ten indexes and the index of the standard is : per capita GNP is more than $3,000 , Agricultural output value of GDP ratio below 12 % , Services output value of the proportion of GDP more than 45% , The proportion of labor force non-agriculture is more than 70% , More than 80% of the population proportion of literacy , In proportion as young students school-age 10-15% , Every doctor service in the number of people under 1000 people, The average life expectancy is more than 70 years old, Infant natural mortality rates below 3% , The proportion of urban population is more than 50%, the natural growth rate of people below 1%.
Table 1 the evaluation index system first-order indexes secondary indexes standard value social and economic development level (A) Personnel per capita electricity consumption in the primary industry (A1) 1500 The non-agricultural population proportion (A2) 5 The specific gravity of Industrial added value in GDP (A3) 2 The agricultural investment level(B) The cultivatedareas per hectare of mechanical total power (B1) 15 The proportion in effective irrigated area(B2) 90 Penetration rate of three stations in rural areas (B3) 90 The proportion of serve jobholder in total employees (B4) 5 The comprehensive output level of agricultural (C) The sown area of grain yield (C1) 5000 Each rural agricultural Labour force create gross output value of agricultural(C2) 10000 Per capita meat production (C3) 200 The commodity rate of agricultural and sideline products (C4) 90 The living standards of famers(D) Rural per
Here, if some index of actual value or critical value is o or negative number, we should make it adding a proper number, so that it can be change into positive number, it can be dimensionless process.
In this paper we let each number add 1 and then go on dimensionless process. 4.3Calculating the weight of each index.
Online since: March 2015
Authors: Wen Tao Qu, Si Ying Liu, Zhang Shi Xu
For example, Sichuan Gas Field has a content of H2S of 1%~13%(volume fraction), while it is 0.0003%~1.92% in Shanganning Gas Field, and that number could be as high as 90% in certain oil/gas wells.
Table 1 Chemical Composition % C Si Mn S P Ni Mo 0.21 0.29 0.75 0.016 0.021 1.71 0.27 Table 2 Metallurgical Structure Grain Size Metallurgical Structure Inclusion Grade 4 Tempered Sorbite & Ferrite A0.5B0.5D1.0 Table 3 Strength Grade Tensile Strength/MPa Yield Strength /MPa Elongation/% 651 485 26 The size of one piece of specimen is 25.42mm×3.12mm,and the amount is 36.
Specimen are numbered by three digits before the experiment, instructions of the numbers are shown below: 1(6%H2S) 2(20Ni2Mo) 2(10%H2S) Serial Number 3(20%H2S) Procedures of the treatments of the specimen before the experiment: (1)Polished by 200#, 400# and 600# sandpaper in sequence; (2)Rinsed by water; (3)Acetone degreasing treatment; (4)Weighed and measured the dimensional parameters of the specimen; (5)Placed in drier waiting to be used in the experiment.
Table 4 Part of results of the experiment(under the temperature of 100℃) Serial Number Original mass of specimen m0 /g Mass of specimen after corrosion m /g (m0-m)/g Corrosion rate v/mm·a-1 Average corrosion rate v/mm·a-1 211 11.6405 11.6160 0.0245 0.30706 212 11.5955 11.5738 0.0217 0.27197 0.28952 213 11.5568 -- -- 221 11.5802 11.5547 0.0255 0.31959 222 11.4293 11.4057 0.0236 0.29578 0.30769 223 11.6512 -- -- 231 11.5597 11.5357 0.024 0.30079 232 11.5823 11.5558 0.0265 0.33212 0.31646 233 11.5225 -- 0.30706 Table 5 Part of results of the experiment(under the temperature of 25℃) Serial Number Original mass of specimen m0 /g Mass of specimen after corrosion m0 /g (m0-m)/g Corrosion rate v/mm·a-1 Average corrosion v /mm·a-1 211 11.5593 11.5458 0.0135 0.1692 212 11.4563 -- -- 0.16857 213 11.4913 11.4779 0.0134 0.16794 221 11.4288 11.4080 0.0208 0.26069 222 11.4578 11.4376 0.0202 0.25317 0.25693 223 11.4881 -- -- 231 11.4555 11.4243 0.0312 0.39103 232 11.5441 11.5131
Table 1 Chemical Composition % C Si Mn S P Ni Mo 0.21 0.29 0.75 0.016 0.021 1.71 0.27 Table 2 Metallurgical Structure Grain Size Metallurgical Structure Inclusion Grade 4 Tempered Sorbite & Ferrite A0.5B0.5D1.0 Table 3 Strength Grade Tensile Strength/MPa Yield Strength /MPa Elongation/% 651 485 26 The size of one piece of specimen is 25.42mm×3.12mm,and the amount is 36.
Specimen are numbered by three digits before the experiment, instructions of the numbers are shown below: 1(6%H2S) 2(20Ni2Mo) 2(10%H2S) Serial Number 3(20%H2S) Procedures of the treatments of the specimen before the experiment: (1)Polished by 200#, 400# and 600# sandpaper in sequence; (2)Rinsed by water; (3)Acetone degreasing treatment; (4)Weighed and measured the dimensional parameters of the specimen; (5)Placed in drier waiting to be used in the experiment.
Table 4 Part of results of the experiment(under the temperature of 100℃) Serial Number Original mass of specimen m0 /g Mass of specimen after corrosion m /g (m0-m)/g Corrosion rate v/mm·a-1 Average corrosion rate v/mm·a-1 211 11.6405 11.6160 0.0245 0.30706 212 11.5955 11.5738 0.0217 0.27197 0.28952 213 11.5568 -- -- 221 11.5802 11.5547 0.0255 0.31959 222 11.4293 11.4057 0.0236 0.29578 0.30769 223 11.6512 -- -- 231 11.5597 11.5357 0.024 0.30079 232 11.5823 11.5558 0.0265 0.33212 0.31646 233 11.5225 -- 0.30706 Table 5 Part of results of the experiment(under the temperature of 25℃) Serial Number Original mass of specimen m0 /g Mass of specimen after corrosion m0 /g (m0-m)/g Corrosion rate v/mm·a-1 Average corrosion v /mm·a-1 211 11.5593 11.5458 0.0135 0.1692 212 11.4563 -- -- 0.16857 213 11.4913 11.4779 0.0134 0.16794 221 11.4288 11.4080 0.0208 0.26069 222 11.4578 11.4376 0.0202 0.25317 0.25693 223 11.4881 -- -- 231 11.4555 11.4243 0.0312 0.39103 232 11.5441 11.5131
Online since: January 2012
Authors: Ernst Kozeschnik, Bernhard Sonderegger, Christof Sommitsch
Basically, a high number of precipitates block dislocation movements and thus hinder plastic deformation, which increases hardness, strength and creep resistance.
In recent years, precipitation kinetic simulations for heat treatments and thermal loading have been carried out successfully on an increasing number of complex materials [3-8].
Input parameters for these calculations are, among others, composition, time-temperature history, grain sizes, dislocations densities and thermodynamic- and diffusion databases.
The results, phase fractions, number densities and particle radii are the ideal input parameter for computing λ.
One finds as final weighted normal distance of cases I and II: (11) With ni, the number of particles per unit area in the glide plane can be calculated immediately.
In recent years, precipitation kinetic simulations for heat treatments and thermal loading have been carried out successfully on an increasing number of complex materials [3-8].
Input parameters for these calculations are, among others, composition, time-temperature history, grain sizes, dislocations densities and thermodynamic- and diffusion databases.
The results, phase fractions, number densities and particle radii are the ideal input parameter for computing λ.
One finds as final weighted normal distance of cases I and II: (11) With ni, the number of particles per unit area in the glide plane can be calculated immediately.
Online since: November 2012
Authors: Zheng Rong Zhao, Hong Xia Yang
Introduction
Loess is mostly formed in arid or semi-arid climatic conditions, due to the dry climate and soil moisture evaporate constantly,the water contained salts such as calcium carbonate and calcium sulfate separated out and precipitated in the soil grain surface, then formed cementation.
Table 3 shows that after dynamic compaction, in area A, the dry density increased by 4%-19%, reaching more than 1.6g/cm3.Void ratio decreased by 7.6%-31.8%, reaching the range of general cohesive soil indicators.Standard penetration number was more than seven hits and the allowable bearing capacity of the foundation increased to 200kPa-230kPa.
Standard penetration number was more than eight hits and the allowable bearing capacity of foundation increased to 210 kPa-250kPa.In area C, dry density increased by 5.5%-13.2% and void ratio reduced by 6%-11.48%.Standard penetration number was more than ten hits and the allowable bearing capacity of foundation higher than 300kPa.The collapsible coefficient of all the test areas are less than 0.005 and the loess collapsibility disappeared, reaching a processing purpose.
compaction area Drilling depth (m) Dry density (g/cm3) Void ratio Standard penetration number (hits) Allowable bearing capacity (kPa) Collapsible coefficient Before A 3.75 1.50 0.815 6 160 0.042 B 5.70 1.53 0.787 8 180 0.031 C 8.75 1.56 0.757 16 210 0.041 After A 4.00 1.61 0.715 8 220 0.004 B 6.90 1.62 0.701 10 240 0.002 C 8.75 1.69 0.677 17 320 0.003 Construction Quality Control of Dynamic Compaction The Key Problems in the Process of Construction
The construction of less higher steps can refer to the above requirements. (5)When the original ground surface is wet or large moisture content, put 10cm to 20cm thick stone ballast or gravel before tamping in the sections, then compacting and keep filling up. (6)Winter construction, if frozen soil thickness is less than 0.5m,increase 2 to 3 strike in the original tamping number, when frozen soil thickness is bigger than 0.5m,stop construction.
Table 3 shows that after dynamic compaction, in area A, the dry density increased by 4%-19%, reaching more than 1.6g/cm3.Void ratio decreased by 7.6%-31.8%, reaching the range of general cohesive soil indicators.Standard penetration number was more than seven hits and the allowable bearing capacity of the foundation increased to 200kPa-230kPa.
Standard penetration number was more than eight hits and the allowable bearing capacity of foundation increased to 210 kPa-250kPa.In area C, dry density increased by 5.5%-13.2% and void ratio reduced by 6%-11.48%.Standard penetration number was more than ten hits and the allowable bearing capacity of foundation higher than 300kPa.The collapsible coefficient of all the test areas are less than 0.005 and the loess collapsibility disappeared, reaching a processing purpose.
compaction area Drilling depth (m) Dry density (g/cm3) Void ratio Standard penetration number (hits) Allowable bearing capacity (kPa) Collapsible coefficient Before A 3.75 1.50 0.815 6 160 0.042 B 5.70 1.53 0.787 8 180 0.031 C 8.75 1.56 0.757 16 210 0.041 After A 4.00 1.61 0.715 8 220 0.004 B 6.90 1.62 0.701 10 240 0.002 C 8.75 1.69 0.677 17 320 0.003 Construction Quality Control of Dynamic Compaction The Key Problems in the Process of Construction
The construction of less higher steps can refer to the above requirements. (5)When the original ground surface is wet or large moisture content, put 10cm to 20cm thick stone ballast or gravel before tamping in the sections, then compacting and keep filling up. (6)Winter construction, if frozen soil thickness is less than 0.5m,increase 2 to 3 strike in the original tamping number, when frozen soil thickness is bigger than 0.5m,stop construction.