Reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal shearers.Tool bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the...Reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal shearers.Tool bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the main reasons for failure of cutting picks.We carried out carburization on a 30CrMnMo alloy to synthesize a new cutting pick material with improved mechanical properties and high wear resistance.The results indicated that carburization can effectively strengthen the surface of the 30CrMnMo alloy by forming a thick carburized layer and thus significantly improve the surface hardness and wear resistance.In addition,the excellent toughness of 30CrMnMo alloy as a substrate of cutting picks can prevent brittle ruptures and fatigue fractures under high impact stress conditions.The significant decrease in both frictional coefficient and rate of erosion of this carburized 30CrMnMo alloy suggests that this alloy is a potential material for cutting picks of coal shearers after rational carburization.展开更多
It's November 27,1978."Uu Chuanzhi,then a 34-year-old researcher at the Institute of Computing Technology of the Chinese Academy of Sciences,gets to work on time. Before stepping into the office,he picks up a...It's November 27,1978."Uu Chuanzhi,then a 34-year-old researcher at the Institute of Computing Technology of the Chinese Academy of Sciences,gets to work on time. Before stepping into the office,he picks up a thermos bottle filled with hot water from the reception area,makes casual jokes with the senior doorkeeper and picks up a copy of People's Dailyfrom his mailbox.Normally,he will idle his entire morning reading the paper and drinking tea until lunch time."展开更多
Ⅰ. The Development Plan for Auto-electronic technology in China 1. The Status Quo of China’s Auto-electronic Technology Application There is a clear disparity between China and developed countries in the field of au...Ⅰ. The Development Plan for Auto-electronic technology in China 1. The Status Quo of China’s Auto-electronic Technology Application There is a clear disparity between China and developed countries in the field of auto-electronic technology. The comprehensive level of China today’s auto-electronic展开更多
Local residents in Xiahe County, Gansu Province, clear up debris left by floodwaters on August 20. People’s Daily Online reported that rains triggered mudrock flows that hit seven villages in three towns on August 19...Local residents in Xiahe County, Gansu Province, clear up debris left by floodwaters on August 20. People’s Daily Online reported that rains triggered mudrock flows that hit seven villages in three towns on August 19. About 3,000 rooms in the county’s houses are reported to have collapsed and more than 11,400 were flooded. Three people were killed and one was missing. A 30-meter section of highway linking Xiahe and other regions was blocked by falling rocks and mud. The report said the county government had mobilized staff for disaster-relief work.展开更多
基金the Youth Foundation of China University of Mining & Technology (No.2009A056)the Tribology Science Fund from State Key Laboratory of Tribology at Tsinghua University (No.SKLTKF08A01)+1 种基金the National Natural Science Foundation of China (Nos.50905180 and 51005234)the National Science and Technology Pillar Program in the Eleventh Five-Year Plan Period (No.2008BAB36B02)
文摘Reliability and wear resistance of cutting picks play a significant role in coal mine exploitation with coal shearers.Tool bit separation,blade breaking,severe erosion of the cutting body and fatigue fractures are the main reasons for failure of cutting picks.We carried out carburization on a 30CrMnMo alloy to synthesize a new cutting pick material with improved mechanical properties and high wear resistance.The results indicated that carburization can effectively strengthen the surface of the 30CrMnMo alloy by forming a thick carburized layer and thus significantly improve the surface hardness and wear resistance.In addition,the excellent toughness of 30CrMnMo alloy as a substrate of cutting picks can prevent brittle ruptures and fatigue fractures under high impact stress conditions.The significant decrease in both frictional coefficient and rate of erosion of this carburized 30CrMnMo alloy suggests that this alloy is a potential material for cutting picks of coal shearers after rational carburization.
文摘It's November 27,1978."Uu Chuanzhi,then a 34-year-old researcher at the Institute of Computing Technology of the Chinese Academy of Sciences,gets to work on time. Before stepping into the office,he picks up a thermos bottle filled with hot water from the reception area,makes casual jokes with the senior doorkeeper and picks up a copy of People's Dailyfrom his mailbox.Normally,he will idle his entire morning reading the paper and drinking tea until lunch time."
文摘Ⅰ. The Development Plan for Auto-electronic technology in China 1. The Status Quo of China’s Auto-electronic Technology Application There is a clear disparity between China and developed countries in the field of auto-electronic technology. The comprehensive level of China today’s auto-electronic
文摘Local residents in Xiahe County, Gansu Province, clear up debris left by floodwaters on August 20. People’s Daily Online reported that rains triggered mudrock flows that hit seven villages in three towns on August 19. About 3,000 rooms in the county’s houses are reported to have collapsed and more than 11,400 were flooded. Three people were killed and one was missing. A 30-meter section of highway linking Xiahe and other regions was blocked by falling rocks and mud. The report said the county government had mobilized staff for disaster-relief work.
