Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the tempe...Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the temperature structure along 35°N section is the double cold cores phenomena during spring and summer. The double cold cores refer to the two cold water centers located near 122°E and 125°E from the depth of 30m to bottom. The formation, maintenance and disappearance of the double cold cores are discussed. At least two reasons make the temperature in the center (near 123°E) of the section higher than that near the west and east shores in winter. One reason is that the water there is deeper than the west and east sides so its heat content is higher. The other is invasion of the warm water brought by the Yellow Sea Warm Current (YSWC) during winter.This temperature pattern of the lower layer (from 30m to bottom) is maintained through spring and summer when the upper layer (0 to 30m) is heated and strong thermocline is formed. Large zonal span of the 35°N section (about 600 km) makes the cold cores have more opportunity to survive. The double cold cores phenomena disappears in early autumn when the west cold core vanishes first with the dropping of the thermocline position.展开更多
This paper presents the erosion results of the AISI H13 steel impinged by resin-bonded silica sand, using a testing rig that closely simulates the real blowing conditions during industrial core-making. Steel specimens...This paper presents the erosion results of the AISI H13 steel impinged by resin-bonded silica sand, using a testing rig that closely simulates the real blowing conditions during industrial core-making. Steel specimens were heat treated to obtain hardness of 294, 445 and 595 HV200 (29, 45 and 55 HRC). Erosion tests were carried out at impingement angles from 20° to 90° and air drag pressures of 1.38, 2.07 and 2.76 bar (20, 30 and 40 psi). The main results are summarized as follows:(i) The harder material, the lower erosion;(ii) the maximum erosion rate is at 30°;(iii) Little difference in erosion rate at impact angle of 60° and 90° for a constant pressure tested regardless of the hardness level;(iv) As the pressure increases, so does the erosion rate, being more sensitive for low impact angles. Finally, a differential form of the general erosion equation is applied on a practical core-making case to evaluate the erosion rate of the H13 steel at 30° and 90° impingement angles.展开更多
In this investigation, an attempt has been made to study the influence of welding consumables on the factors that influence cold cracking of armour grade quenched and tempered （Q＆.T） steel welds. Flux cored arc wel...In this investigation, an attempt has been made to study the influence of welding consumables on the factors that influence cold cracking of armour grade quenched and tempered （Q＆.T） steel welds. Flux cored arc welding （FCAW） process were used making welds using austenitic stainless steel （ASS） and low hydrogen ferritic steel （LHF） consumables. The diffusible hydrogen levels in the weld metal of the ASS and LHF consumables were determined by mercury method. Residual stresses were evaluated using X-ray stress analyzer and implant test was carried out to study the cold cracking of the welds. Results indicate that ASS welds offer a greater resistance to cold cracking of armour grade Q＆T steel welds.展开更多
Affiliation unit: Lanzhou Institute of Glaciology and Cold Regions Environment, CAS Brief history: The Laboratory of Ice Core and Cold Regions Environment (LICCRE) was formally approved to open domestically and intern...Affiliation unit: Lanzhou Institute of Glaciology and Cold Regions Environment, CAS Brief history: The Laboratory of Ice Core and Cold Regions Environment (LICCRE) was formally approved to open domestically and internationally by Chinese Academy of Sciences in April 1997. It is attached to the Lanzhou Institute of Glaciology and Geocryology, CAS.展开更多
北极海冰变化与冬季欧亚大陆气温异常变化存在密切联系,而冬季冷高压系统的频繁活动对于西伯利亚以及东亚地区降温产生直接影响,在“北极放大”以及未来北极海冰退缩情景下,西伯利亚近地面反气旋活动如何变化值得深入探究。本研究利用...北极海冰变化与冬季欧亚大陆气温异常变化存在密切联系,而冬季冷高压系统的频繁活动对于西伯利亚以及东亚地区降温产生直接影响,在“北极放大”以及未来北极海冰退缩情景下,西伯利亚近地面反气旋活动如何变化值得深入探究。本研究利用基于深度学习的Mask R-CNN反气旋客观识别算法对欧亚大陆冬季天气尺度反气旋进行识别,使用欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)ERA5再分析资料、美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)OISST V2.1每日海冰密集度数据集以及MIROC6模式输出资料,进一步研究了在未来北极海冰迅速退缩的背景下,前期秋季海冰异常变化可能对反气旋和冷空气活动产生的影响及其机制。结果表明,1981-2022年秋季巴伦支海-卡拉海区域(Barents-Kara Sea,BKS)海冰指数减下降,而欧亚大陆中高纬度特别是西伯利亚区域的气温显著下降,冷空气质量异常堆积,反气旋活动携带的冷空气质量增多。进一步利用北极放大计划(Polar Amplification Model Intercomparison Project,PAMIP)中的模式资料,统计欧亚大陆反气旋在未来北极海冰较少情景下的活动变化规律,发现海冰减少条件下,西伯利亚区是欧亚大陆反气旋的主要影响和生消地之一,该区域反气旋具有局地活动特征,对准定常的西伯利亚冷高压以及冷池区冷空气积聚起重要促进作用。气温在欧亚大陆北边缘增高但在欧亚大陆中纬度呈显著下降特征,伴随着欧亚大陆大部分地区极寒天数增多。进一步研究发现秋季BKS海冰状况可作为前兆因子对后期冬季反气旋活动以及气温异常产生影响,该地区海冰状况引起区域位涡经向梯度显著降低,从而使上游东欧平原阻塞发生频率增大,有利于反气旋活动增强和冷空气的输送,促使东亚冬季寒冷趋势加剧。展开更多
The cold box plus process it discussed in principle When the proper heating to the corebox is given (65℃±2℃). the binder lever can be saved, also the core strength and surface hardnessare imtroved, the moisture...The cold box plus process it discussed in principle When the proper heating to the corebox is given (65℃±2℃). the binder lever can be saved, also the core strength and surface hardnessare imtroved, the moisture-sensitvity is reduced. The mechanism of the cold box plus process isthat the proper heat increases the activity of resin function groups and promotes the crosslinking re-action The result of a scanning electron microscope analysis shows that the core surface strength isimproved by heat展开更多
文摘Based on the MASNUM wave-tide-circulation coupled numerical model, the temperature structure along 35°N in the Yellow Sea was simulated and compared with the observations. One of the notable features of the temperature structure along 35°N section is the double cold cores phenomena during spring and summer. The double cold cores refer to the two cold water centers located near 122°E and 125°E from the depth of 30m to bottom. The formation, maintenance and disappearance of the double cold cores are discussed. At least two reasons make the temperature in the center (near 123°E) of the section higher than that near the west and east shores in winter. One reason is that the water there is deeper than the west and east sides so its heat content is higher. The other is invasion of the warm water brought by the Yellow Sea Warm Current (YSWC) during winter.This temperature pattern of the lower layer (from 30m to bottom) is maintained through spring and summer when the upper layer (0 to 30m) is heated and strong thermocline is formed. Large zonal span of the 35°N section (about 600 km) makes the cold cores have more opportunity to survive. The double cold cores phenomena disappears in early autumn when the west cold core vanishes first with the dropping of the thermocline position.
基金financially supported by NEMAK S.A. and Industria Meccanica Bassi Luigi&Co
文摘This paper presents the erosion results of the AISI H13 steel impinged by resin-bonded silica sand, using a testing rig that closely simulates the real blowing conditions during industrial core-making. Steel specimens were heat treated to obtain hardness of 294, 445 and 595 HV200 (29, 45 and 55 HRC). Erosion tests were carried out at impingement angles from 20° to 90° and air drag pressures of 1.38, 2.07 and 2.76 bar (20, 30 and 40 psi). The main results are summarized as follows:(i) The harder material, the lower erosion;(ii) the maximum erosion rate is at 30°;(iii) Little difference in erosion rate at impact angle of 60° and 90° for a constant pressure tested regardless of the hardness level;(iv) As the pressure increases, so does the erosion rate, being more sensitive for low impact angles. Finally, a differential form of the general erosion equation is applied on a practical core-making case to evaluate the erosion rate of the H13 steel at 30° and 90° impingement angles.
基金Armament Research Board (ARMREB),New Delhi for funding this projectwork (Project No MAA/03/41)
文摘In this investigation, an attempt has been made to study the influence of welding consumables on the factors that influence cold cracking of armour grade quenched and tempered （Q＆.T） steel welds. Flux cored arc welding （FCAW） process were used making welds using austenitic stainless steel （ASS） and low hydrogen ferritic steel （LHF） consumables. The diffusible hydrogen levels in the weld metal of the ASS and LHF consumables were determined by mercury method. Residual stresses were evaluated using X-ray stress analyzer and implant test was carried out to study the cold cracking of the welds. Results indicate that ASS welds offer a greater resistance to cold cracking of armour grade Q＆T steel welds.
文摘Affiliation unit: Lanzhou Institute of Glaciology and Cold Regions Environment, CAS Brief history: The Laboratory of Ice Core and Cold Regions Environment (LICCRE) was formally approved to open domestically and internationally by Chinese Academy of Sciences in April 1997. It is attached to the Lanzhou Institute of Glaciology and Geocryology, CAS.
文摘北极海冰变化与冬季欧亚大陆气温异常变化存在密切联系,而冬季冷高压系统的频繁活动对于西伯利亚以及东亚地区降温产生直接影响,在“北极放大”以及未来北极海冰退缩情景下,西伯利亚近地面反气旋活动如何变化值得深入探究。本研究利用基于深度学习的Mask R-CNN反气旋客观识别算法对欧亚大陆冬季天气尺度反气旋进行识别,使用欧洲中期天气预报中心(European Centre for Medium-Range Weather Forecasts,ECMWF)ERA5再分析资料、美国国家海洋和大气管理局(National Oceanic and Atmospheric Administration,NOAA)OISST V2.1每日海冰密集度数据集以及MIROC6模式输出资料,进一步研究了在未来北极海冰迅速退缩的背景下,前期秋季海冰异常变化可能对反气旋和冷空气活动产生的影响及其机制。结果表明,1981-2022年秋季巴伦支海-卡拉海区域(Barents-Kara Sea,BKS)海冰指数减下降,而欧亚大陆中高纬度特别是西伯利亚区域的气温显著下降,冷空气质量异常堆积,反气旋活动携带的冷空气质量增多。进一步利用北极放大计划(Polar Amplification Model Intercomparison Project,PAMIP)中的模式资料,统计欧亚大陆反气旋在未来北极海冰较少情景下的活动变化规律,发现海冰减少条件下,西伯利亚区是欧亚大陆反气旋的主要影响和生消地之一,该区域反气旋具有局地活动特征,对准定常的西伯利亚冷高压以及冷池区冷空气积聚起重要促进作用。气温在欧亚大陆北边缘增高但在欧亚大陆中纬度呈显著下降特征,伴随着欧亚大陆大部分地区极寒天数增多。进一步研究发现秋季BKS海冰状况可作为前兆因子对后期冬季反气旋活动以及气温异常产生影响,该地区海冰状况引起区域位涡经向梯度显著降低,从而使上游东欧平原阻塞发生频率增大,有利于反气旋活动增强和冷空气的输送,促使东亚冬季寒冷趋势加剧。
文摘The cold box plus process it discussed in principle When the proper heating to the corebox is given (65℃±2℃). the binder lever can be saved, also the core strength and surface hardnessare imtroved, the moisture-sensitvity is reduced. The mechanism of the cold box plus process isthat the proper heat increases the activity of resin function groups and promotes the crosslinking re-action The result of a scanning electron microscope analysis shows that the core surface strength isimproved by heat
