20 research outputs found
Structural Strength and Service Life of the Extrusion Forming Die for Agricultural Engine Piston Heads
Three-tier high-strength prestressed combination concave dies are designed to manifacture highpower corn combine harvester engine piston heads. This design integrates the advantages of traditional casting or hot die forging and warm extrusion. The following key parameters, viz radial dimensions of each mating layer, axial bonding and radial contact interaction, are obtained by theoretical calculation. Nonlinear analysis of the contact interaction was carried out, and the die contact condition was studied at no-load and full-load. Based on the Archard wear theory, thermomechanical bonding was studied in operation of the die. Through numerical simulation of the die wear in each operation cycle, the univariate linear regression equation of the die service life was derived, and the reliability of this equation was verified. The results show that the die contact is both stable and reliable if the radial contact interaction of the inner and outer layers is Ξ΄β= 1.9716 mm and Ξ΄β= 1.3870 mm, respectively. With the nitriding layer thickness of 0.24 mm, the extrusion die service life in the production of piston heads corresponds to 6357 pieces.Π Π°Π·ΡΠ°Π±ΠΎΡΠ°Π½Ρ ΡΡΠ΅Ρ
ΡΡΡΡΡΠ½ΡΠ΅ Π²ΡΡΠΎΠΊΠΎΠΏΡΠΎΡΠ½ΡΠ΅ ΠΏΡΠ΅Π΄Π²Π°ΡΠΈΡΠ΅Π»ΡΠ½ΠΎ-Π½Π°ΠΏΡΡΠΆΠ΅Π½Π½ΡΠ΅ ΠΌΠ½ΠΎΠ³ΠΎΠΌΠ΅ΡΡΠ½ΡΠ΅ Π²ΠΎΠ³Π½ΡΡΡΠ΅ Π³ΠΎΠ»ΠΎΠ²ΠΊΠΈ Π΄Π»Ρ ΠΈΠ·Π³ΠΎΡΠΎΠ²Π»Π΅Π½ΠΈΡ Π΄Π½ΠΈΡ ΠΏΠΎΡΡΠ½Ρ Π΄Π²ΠΈΠ³Π°ΡΠ΅Π»Ρ ΠΌΠΎΡΠ½ΠΎΠ³ΠΎ ΠΊΡΠΊΡΡΡΠ·ΠΎΡΠ±ΠΎΡΠΎΡΠ½ΠΎΠ³ΠΎ ΠΊΠΎΠΌΠ±Π°ΠΉΠ½Π°. ΠΠΎΠ½ΡΡΡΡΠΊΡΠΈΡ ΡΠΎΠ΅Π΄ΠΈΠ½ΡΠ΅Ρ Π² ΡΠ΅Π±Π΅ ΠΏΡΠ΅ΠΈΠΌΡΡΠ΅ΡΡΠ²Π° Π»ΠΈΡΡΡ ΠΈΠ»ΠΈ Π³ΠΎΡΡΡΠ΅ΠΉ ΠΊΠΎΠ²ΠΊΠΈ ΠΈ Π³ΠΎΡΡΡΠ΅ΠΉ ΡΠΊΡΡΡΡΠ·ΠΈΠΈ. Π Π°Π΄ΠΈΠ°Π»ΡΠ½ΡΠ΅ ΡΠ°Π·ΠΌΠ΅ΡΡ ΠΊΠ°ΠΆΠ΄ΠΎΠ³ΠΎ ΡΠΎΠ΅Π΄ΠΈΠ½ΡΠ΅ΠΌΠΎΠ³ΠΎ ΡΠ»ΠΎΡ, ΠΎΡΠ΅Π²ΠΎΠ΅ ΡΡΠ΅ΠΏΠ»Π΅Π½ΠΈΠ΅ ΠΈ ΡΠ°Π΄ΠΈΠ°Π»ΡΠ½ΠΎΠ΅ ΠΊΠΎΠ½ΡΠ°ΠΊΡΠ½ΠΎΠ΅ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠ΅ ΡΠ°ΡΡΡΠΈΡΠ°Π½Ρ ΡΠ΅ΠΎΡΠ΅ΡΠΈΡΠ΅ΡΠΊΠΈ. ΠΡΠΏΠΎΠ»Π½Π΅Π½ Π½Π΅Π»ΠΈΠ½Π΅ΠΉΠ½ΡΠΉ Π°Π½Π°Π»ΠΈΠ· ΠΊΠΎΠ½ΡΠ°ΠΊΡΠ½ΠΎΠ³ΠΎ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΡ, ΠΈΠ·ΡΡΠ΅Π½Ρ ΡΡΠ»ΠΎΠ²ΠΈΡ ΠΊΠΎΠ½ΡΠ°ΠΊΡΠΈΡΠΎΠ²Π°Π½ΠΈΡ Π² Π³ΠΎΠ»ΠΎΠ²ΠΊΠ΅ ΠΏΡΠΈ Π½ΡΠ»Π΅Π²ΠΎΠΉ ΠΈ ΠΏΠΎΠ»Π½ΠΎΠΉ Π½Π°Π³ΡΡΠ·ΠΊΠ΅. ΠΠ° ΠΎΡΠ½ΠΎΠ²Π°Π½ΠΈΠΈ ΡΠ΅ΠΎΡΠΈΠΈ ΠΈΠ·Π½ΠΎΡΠ° ΠΡΡΠ°ΡΠ΄Π° Π²ΡΠΏΠΎΠ»Π½Π΅Π½Π° ΠΎΡΠ΅Π½ΠΊΠ° ΡΠ΅ΡΠΌΠΎΠΌΠ΅Ρ
Π°Π½ΠΈΡΠ΅ΡΠΊΠΎΠ³ΠΎ ΡΡΠ΅ΠΏΠ»Π΅Π½ΠΈΡ Π² ΠΏΡΠΎΡΠ΅ΡΡΠ΅ ΡΠΊΡΠΏΠ»ΡΠ°ΡΠ°ΡΠΈΠΈ Π³ΠΎΠ»ΠΎΠ²ΠΊΠΈ. ΠΡΡΠ΅ΠΌ ΡΠΈΡΠ»Π΅Π½Π½ΠΎΠ³ΠΎ ΠΌΠΎΠ΄Π΅Π»ΠΈΡΠΎΠ²Π°Π½ΠΈΡ ΠΈΠ·Π½ΠΎΡΠ° Π³ΠΎΠ»ΠΎΠ²ΠΊΠΈ Π² ΠΊΠ°ΠΆΠ΄ΠΎΠΌ ΡΠ°Π±ΠΎΡΠ΅ΠΌ ΡΠΈΠΊΠ»Π΅ ΠΏΠΎΠ»ΡΡΠ΅Π½ΠΎ ΠΎΠ΄Π½ΠΎΠΏΠ°ΡΠ°ΠΌΠ΅ΡΡΠΈΡΠ΅ΡΠΊΠΎΠ΅ ΡΡΠ°Π²Π½Π΅Π½ΠΈΠ΅ Π»ΠΈΠ½Π΅ΠΉΠ½ΠΎΠΉ ΡΠ΅Π³ΡΠ΅ΡΡΠΈΠΈ Π΄Π»Ρ ΡΡΠΎΠΊΠ° Π΅Π΅ ΡΠ»ΡΠΆΠ±Ρ; ΠΏΡΠΎΠ²Π΅ΡΠ΅Π½Π° Π΄ΠΎΡΡΠΎΠ²Π΅ΡΠ½ΠΎΡΡΡ Π΄Π°Π½Π½ΠΎΠ³ΠΎ ΡΡΠ°Π²Π½Π΅Π½ΠΈΡ. ΠΠΎΠΊΠ°Π·Π°Π½ΠΎ, ΡΡΠΎ ΠΊΠΎΠ½ΡΠ°ΠΊΡ Π² Π³ΠΎΠ»ΠΎΠ²ΠΊΠ΅ ΡΡΡΠΎΠΉΡΠΈΠ² ΠΈ Π½Π°Π΄Π΅ΠΆΠ΅Π½, ΠΏΡΠΈ ΡΠ°Π΄ΠΈΠ°Π»ΡΠ½ΠΎΠΌ ΠΊΠΎΠ½ΡΠ°ΠΊΡΠ½ΠΎΠΌ Π²Π·Π°ΠΈΠΌΠΎΠ΄Π΅ΠΉΡΡΠ²ΠΈΠΈ Π²Π½ΡΡΡΠ΅Π½Π½Π΅Π³ΠΎ ΠΈ Π½Π°ΡΡΠΆΠ½ΠΎΠ³ΠΎ ΡΠ»ΠΎΠ΅Π² Ξ΄β= 1.9716 ΠΌΠΌ ΠΈ Ξ΄β= 1.3870 ΠΌΠΌ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²Π΅Π½Π½ΠΎ. ΠΡΠΈ ΡΠΎΠ»ΡΠΈΠ½Π΅ Π½ΠΈΡΡΠΈΠ΄Π½ΠΎΠ³ΠΎ ΡΠ»ΠΎΡ 0,24 ΠΌΠΌ ΡΡΠΎΠΊ ΡΠ»ΡΠΆΠ±Ρ ΡΠΊΡΡΡΡΠ·ΠΈΠΎΠ½Π½ΠΎΠΉ Π³ΠΎΠ»ΠΎΠ²ΠΊΠΈ Π² ΠΏΡΠΎΠΈΠ·Π²ΠΎΠ΄ΡΡΠ²Π΅ Π΄Π½ΠΈΡ ΠΏΠΎΡΡΠ½Ρ ΡΠΎΠΎΡΠ²Π΅ΡΡΡΠ²ΡΠ΅Ρ 6357 ΠΈΠ·Π΄Π΅Π»ΠΈΡΠΌ
The superconductivity at 18 K in LiFeAs system
A new iron arsenide superconducting system LiFeAs was found that crystallizes
into a tetragonal structure with space group P4/nmm. The superconductivity with
Tc up to 18 K was observed in the compounds. This simple 111 type layered iron
arsenide superconductor can be viewed as an analogue of the infinite layer
structure of copper oxides.Comment: 11 pages 3 Figure
Microstructure, properties and application of YAl2 intermetallic compound as particle reinforcements
Clinical Research for the Effectiveness and Economic Value of Qinxitong in the Patients with Ra in China
The photosynthetic function analysis for leaf photooxidation in rice
Photooxidative damage causes early leaf senescence and plant cell death. In this study, a light-sensitive rice cultivar, 812HS, and a non-light-sensitive cultivar, 812S, were used to investigate early leaf photooxidation. Leaf tips of 812HS exhibited yellowing under a light intensity of 720 Β΅mol(photon) m-2 s-1, accompanied by a decrease in chlorophyll and carotenoids, but 812S was unaffected. The photosynthetic performance of 812HS was also poorer than that of 812S. The H2O2, O2*-, and malondialdehyde content increased sharply in 812HS, and associated antioxidant enzymes were inhibited. The degradation of core proteins in both PSI and PSII, as well as other photosynthesis-related proteins, was accelerated in 812HS. When shaded [180 Β΅mol(photon) m-2 s-1], 812HS recovered to normal. Therefore, our findings suggested excess light disturbed the balance of ROS metabolism, leading to the destruction of the antioxidant system and photosynthetic organs, and thus triggering the senescence of rice leaves