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Online since: December 2010
Authors: Li Wei Li, Jin Xu Li, Y.J. Su, W.Y. Chu, L.J. Qiao
The specimens in dimensions of 0.9 × 8 × 25 mm3 were cut from the bulk with an average grain of 2.5μm.
(1) where g0 is the surface energy without adsorption, g(t¥) the surface energy of the adsorbed sample after saturation sorption, n the total number of surface sites per unit area, k a constant, N=6.023´1023, R=8.314 J/mol·K, [HL] the activity of hydrogen.
For the sorption of molecular hydrogen or water steam, q=K[HL]/(1+K[HL])=(kP)1/2/[1+(kP)1/2], where θ is the fractional number of surface sites that are covered by adsorbed species, P is the pressure, k is also a constant.
(1) where g0 is the surface energy without adsorption, g(t¥) the surface energy of the adsorbed sample after saturation sorption, n the total number of surface sites per unit area, k a constant, N=6.023´1023, R=8.314 J/mol·K, [HL] the activity of hydrogen.
For the sorption of molecular hydrogen or water steam, q=K[HL]/(1+K[HL])=(kP)1/2/[1+(kP)1/2], where θ is the fractional number of surface sites that are covered by adsorbed species, P is the pressure, k is also a constant.
Online since: February 2011
Authors: Jun Hong Li
With the rapid development of economy and the deepening of China's western development, a large number of railways, roads and pipes of transporting oil, gas and water are built.
These tunnels safety is related to both its own geological characteristics and many various kinds of natural factors, such as earthquakes and environmental vibration caused by volcanic eruption and explosion. “5.12 Wenchuan” earthquake caused a large number of tunnels collapse, rail and road traffic disruption, destroying water conservancy and hydroelectric engineering facilities and so on, bringing a huge economic loose to the country and people’s life and properties.
Its stress-strain characteristic is influenced by the grain size, structure characteristics, stress history and drainage condition, etc.
These tunnels safety is related to both its own geological characteristics and many various kinds of natural factors, such as earthquakes and environmental vibration caused by volcanic eruption and explosion. “5.12 Wenchuan” earthquake caused a large number of tunnels collapse, rail and road traffic disruption, destroying water conservancy and hydroelectric engineering facilities and so on, bringing a huge economic loose to the country and people’s life and properties.
Its stress-strain characteristic is influenced by the grain size, structure characteristics, stress history and drainage condition, etc.
Online since: October 2011
Authors: Wei Bo Huang, Jia Yu Xiang, Ping Lv, Xin Mao Li
A large number of advantages can be obtained when applying it to hydraulic concrete for protection.
After a certain number of cycles, polyurea coating mechanical strength appeared different degree of declining, mainly due to the coating internal structure that achieved certain close-grained degree and the hydrogen bonding and crosslinking degree were basically completed.
After a certain number of cycles, polyurea coating mechanical strength appeared different degree of declining, mainly due to the coating internal structure that achieved certain close-grained degree and the hydrogen bonding and crosslinking degree were basically completed.
Online since: November 2013
Authors: Jie Zhang, Ling Guang Kong, Hong Bo Li, Yuan Wei Yuan, Xiao Jun Chai, Bing Sheng Wang
Under the influence of the triaxial stress state, the grain of the metal refines and the strength increases, accompanied with work hardening.
a)cupping model b)calculation results Fig. 3 Cupping model and calculation results of can body 1-punch 2-blank holder 3-blank 4-die In the ABAQUS models of cupping process and ironing process, the material of the can body was Al3104 H19; the element type was linear reduced-integration element CAX4R, which could be used to simulate the large strain in the ironing process of the sidewall, and the total number of elements was 1950.
The moulds were regarded as rigid bodies; the element type was linear rigid element; the number of the cupping model was 215 and that of ironing model was 314.
a)cupping model b)calculation results Fig. 3 Cupping model and calculation results of can body 1-punch 2-blank holder 3-blank 4-die In the ABAQUS models of cupping process and ironing process, the material of the can body was Al3104 H19; the element type was linear reduced-integration element CAX4R, which could be used to simulate the large strain in the ironing process of the sidewall, and the total number of elements was 1950.
The moulds were regarded as rigid bodies; the element type was linear rigid element; the number of the cupping model was 215 and that of ironing model was 314.
Online since: December 2012
Authors: Feng Wei He, Tong Lui, Ya Qin Zhang
in the preparation of high performance, high functionality of the concrete material, and its role more important than cement in the concrete [1]. aminosulphonic acid-based Superplasticizer(ASP) with high water reducing rate control concrete slump loss characteristics, improving concrete workability and durability, is the most promising new superplasticizer [2]
Experiment
1.1 The experimental materials
Superplasticizer: aminosulphonic acid-based Superplasticizer(ASP),(self – made); naphthalene superplasticizer (FDN),( Anhui );
Table.l Physical-chemistry properties of the product of ASP
Exterior
Density /(g·cm-3)
Cl- Content /%
Total alkali content /%
pH
Solid content /%
Brown red transparent liquid
1.13
0.05
3.50
11.0
34.0
Cement: Benxi Gongyuan cement plant P·O 42.5 Cement; Benxi jiaotong cement plant P·O 42.5 Cement; Shenyang Jidong P·O 42.5 Cement;Changbai cement plant P•O 52.5 Cement; Changbai cement plant P•O 42.5 Cement;Sand:coarse sand, density 2650kg/m3; limestone gravel, grain
Table.7 The composition of fresh concrete and its harding performance Number ASP (%) Water- Ce- ment ratio Out machine water reducing rate (%) Setting time(min) The amount of change at every hour Compressive strength(MPa) Slump (mm) Gas content (%) The initial setting The final setting Slump (mm) Gas content (%) R3 R7 R28 A12 0 0.70 186 1.8 0 7:46 10:48 11.3 19.6 27.1 A13 1.7 0.52 225 2.7 25.7 9:38 11:35 195 2.3 21.5/190 33.7/172 42.4/157 Table.8 The mechanical properties of fresh concrete Number Splitting tensile strength(MPa) Flexural strength(MPa) Axial compressive strength(MPa) Elastic modulus(×104) ImperviousP10 Seepage height(mm) Slow freezing 50 times Loss of strength (%) Shrinkage values (×10-6) A12 2.85 4.80 20.4 3.16 133 20 283 A13 2.99/105 5.31/110 33.5/116 3.65/116 16 15 304/107 Table 7 and Table 8 shows that,the ASP has significantly slump holding action,fresh concrete performance and compressive strength, shrinkage and other properties are in line with
Table.7 The composition of fresh concrete and its harding performance Number ASP (%) Water- Ce- ment ratio Out machine water reducing rate (%) Setting time(min) The amount of change at every hour Compressive strength(MPa) Slump (mm) Gas content (%) The initial setting The final setting Slump (mm) Gas content (%) R3 R7 R28 A12 0 0.70 186 1.8 0 7:46 10:48 11.3 19.6 27.1 A13 1.7 0.52 225 2.7 25.7 9:38 11:35 195 2.3 21.5/190 33.7/172 42.4/157 Table.8 The mechanical properties of fresh concrete Number Splitting tensile strength(MPa) Flexural strength(MPa) Axial compressive strength(MPa) Elastic modulus(×104) ImperviousP10 Seepage height(mm) Slow freezing 50 times Loss of strength (%) Shrinkage values (×10-6) A12 2.85 4.80 20.4 3.16 133 20 283 A13 2.99/105 5.31/110 33.5/116 3.65/116 16 15 304/107 Table 7 and Table 8 shows that,the ASP has significantly slump holding action,fresh concrete performance and compressive strength, shrinkage and other properties are in line with
Online since: October 2018
Authors: Mikhail A. Filippov, G. Yagudin, V. Legchilo, M. Khadiyev, Svetlana Kh. Estemirova, N. Ozerets
Although the wear resistance of samples, for example, from steels with 0.7-0.8% C with the structure of sorbitol tempering, is 55-70% of the level provided by samples of steel 110G13L [1] when tested on a fixed abrasive [1], a lower cost, manufacturing and environmental problems can be solved in a number of cases with the use of pearlite steel.
Thus, using the steels of the pearlitic and ledeburite classes 150HNML and H12ML it was shown that, as a result of quenching from the normal temperature (850 °C), the microstructure of fine-grained martensite with excess carbides provides high hardness (61 НRC), but the maximum abrasion wear resistance is achieved after high-temperature hardening of steel (1100 ÷ 1175 °C), which forms a martensitic-carbide structure with metastable austenite in the amount of 15-25% and high friction hardening ability [4, 5].
However, the use of pearlitic steels allows one to achieve a lower cost and to solve techno-engineering and ecology issues in a number of cases.
Thus, using the steels of the pearlitic and ledeburite classes 150HNML and H12ML it was shown that, as a result of quenching from the normal temperature (850 °C), the microstructure of fine-grained martensite with excess carbides provides high hardness (61 НRC), but the maximum abrasion wear resistance is achieved after high-temperature hardening of steel (1100 ÷ 1175 °C), which forms a martensitic-carbide structure with metastable austenite in the amount of 15-25% and high friction hardening ability [4, 5].
However, the use of pearlitic steels allows one to achieve a lower cost and to solve techno-engineering and ecology issues in a number of cases.
Online since: May 2020
Authors: Yu.M. Berezhnoi, V.M. Lipkin, D.N. Kuznetsov, O.N. Romanova
Characteristic features of complex electrolytes have been the subject of research of a number of authors [6-8].
Predominant formation of three-dimensional embryos on polished titanium cathode and additive in the electrolyte of polyacrylamide corresponds to the largest share nanosized fraction in the granulometric composition and reduced number of oxygen in the resulting powders. 2.
Rashchi, Recovery of ultra fine grained silver and copper from PC board scraps, Separation and Purification Technology. 92(2012) 36–42
Predominant formation of three-dimensional embryos on polished titanium cathode and additive in the electrolyte of polyacrylamide corresponds to the largest share nanosized fraction in the granulometric composition and reduced number of oxygen in the resulting powders. 2.
Rashchi, Recovery of ultra fine grained silver and copper from PC board scraps, Separation and Purification Technology. 92(2012) 36–42
Online since: July 2014
Authors: Meng Dong Chen, Xiang Bin Li, Min Li
More and more users are willing to share opinions on microblogs, blogs, forums and other platforms to exchange ideas and emotions which include a large number of users’ comment on events, products, people and other objects.
The advantage of using sentiment dictionary to analyze the text sentiment is the precise fine-grained classification on word level and sentence level.
(2) If a negative word wb appears around wi to qualify the sentimental word, judge whether to invert the polarity of wi according to number of negative words.
The advantage of using sentiment dictionary to analyze the text sentiment is the precise fine-grained classification on word level and sentence level.
(2) If a negative word wb appears around wi to qualify the sentimental word, judge whether to invert the polarity of wi according to number of negative words.
Online since: February 2014
Authors: Chun Hui Zhou, Gou Jun Luo, Di Chen, Yu Xia, Li Wen Huang
(2)
Where I(∙) is indicative function, and ε is tolerance. m and n respectively indicate the number of bands of sample A and B. z- and z+ indicate the minimum and maximum of band.
Although carrying on statistics and analysis the total records is possible, the results are at a much coarse-grained level for user multiple interests.
Fi indicate the request rate of user for a particular type image, which it equals to divide the number of one cluster by the total of user’s historical record.
Although carrying on statistics and analysis the total records is possible, the results are at a much coarse-grained level for user multiple interests.
Fi indicate the request rate of user for a particular type image, which it equals to divide the number of one cluster by the total of user’s historical record.
Online since: November 2020
Authors: Mohammed T. Hussein, Fouad A. Senaed
The band at the range (1067.79-1420)cm-1 is for stretching bond of C-N, in addition to appearance a number of bands such as C=C at(1609.79)cm-1 ,Benzene ring band at (1507.8)cm-1 .
Wave number (cm-1) Transmission %100 ℅ T) Figure (10): FT-IR spectra of CuPc powder.
The value related to optical energy gap is slightly decreasing as thickness is increased, such behavior has been because of the growth related to grain size as well as the increase in defect states near the bands.
Wave number (cm-1) Transmission %100 ℅ T) Figure (10): FT-IR spectra of CuPc powder.
The value related to optical energy gap is slightly decreasing as thickness is increased, such behavior has been because of the growth related to grain size as well as the increase in defect states near the bands.