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车身一体化铝合金压铸件工艺探究

特种铸造及有色合金 2024年第4期44卷 568-570页

作者：赵继松吴广坚张慧军上海多利汽车配件有限公司上海201804 盐城多利汽车零部件有限公司盐城224000

采用免热处理铝合金在60 000 kN以上压铸机上制备汽车车身一体化铝合金压铸件,研究工艺参数对其内部品质和力学性能的影响。通过X光检验压铸件内部品质,发现其末端容易形成不良,影响其力学性能。通过对比一体化铝合金压铸件近端与末端... 详细信息

采用免热处理铝合金在60 000 kN以上压铸机上制备汽车车身一体化铝合金压铸件,研究工艺参数对其内部品质和力学性能的影响。通过X光检验压铸件内部品质,发现其末端容易形成不良,影响其力学性能。通过对比一体化铝合金压铸件近端与末端力学性能,发现由于尺寸大、铝液流程长,差异较大,伸长率差异达到55%。通过优化铸造压力、提高压射速度、增大高切点,延后低速高速转换点,铝液通过内浇口后快速对模具型腔填充,从而提高压铸件末端致密性,进而改善末端的力学性能。车身一体化铝合金压铸件末端抗拉强度可达220 MPa,屈服强度达到110 MPa,伸长率可达8%,满足整车使用要求。

关键词：铝合金一体化压铸力学性能

维普期刊数据库博看期刊

Numerical analysis for contribution of the Tibetan Plateau to dust aerosols in the atmosphere over the East Asia

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Science China Earth Sciences 2013年第2期56卷 301-310页

作者： MAO Rui GONG DaoYi SHAO YaPing wu guangjian BAO JingDong State Key Laboratory of Earth Surface Processes and Resource Ecology Beijing Normal University Department of Physics Beijing Normal University Institute of Geophysics and Meteorology University of CologneCologne D-50923Germany Institute of Tibetan Plateau Research Chinese Academy of Sciences

Although the Tibetan Plateau is widely thought as a potential dust source to the atmosphere over East Asia,little is known about the temporal changes of Tibetan dust activities and Tibetan dust source *** this study,we address these two issues by analyzing dust storm frequencies and aerosol index through remote sensing data and by means of numerical *** findings indicate that monthly dust profiles over the Tibetan Plateau vary significantly with *** the surface,dust concentration increases from October,reaches its maximum in February March,and then *** the middle to upper troposphere,dust concentration increases from January,reaches its maximum in May June,and decreases *** Tibetan dust sources are important contributors to dust in the atmosphere over the Tibetan Plateau,their contribution to dust in the troposphere over eastern China is *** contribution of Tibetan dust sources to dust in the atmosphere over the Tibetan Plateau decreases sharply with height,from 69% at the surface,40% in the lower troposphere,and 5% in the middle ***,the contribution shows seasonal changes,with dust sources at the surface at approximately 80% between November and May and 45% between June and September;in the middle and upper troposphere,dust sources are between 21% from February to March and less than 5% in the other ***,dust aerosols originating from the Tibetan Plateau contribute to less than 10% of dust in East Asia.

关键词： Tibetan Plateau dust aerosol aerosol index numerical dust modeling dust sources

Carbonaceous particles in Muztagh Ata ice core,West Kunlun Mountains,China

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Chinese Science Bulletin 2008年第21期53卷 3379-3386页

作者： LIU XianQin XU BaiQing YAO TanDong WANG NingLian wu guangjian State Key Laboratory of Cryospheric Science Cold and Arid Regions Environmental and Engineering Research Institute Chinese Academy of Sciences Lanzhou 730000 China Laboratory of Tibetan Environment Changes and Land Surface Processes Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Carbonaceous particles concentrations of OC and EC are determined using a two-step gas chroma-tography system in Muztagh Ata ice core covering the time period of 1955―*** the period rep-resented by the core,OC and EC concentrations appear to have changed significantly,varied in the range of 17.7―216.7 and 6.5―124.6,and averaged 61.8,32.9 ng·g-1,*** average concen-tration of EC in Muztagh Ata ice core is much lower than that in an Alpine ice core record(100―300 ng·g-1) during the same period,but it is a factor of 14 in Greenland ice core(2.3 ng·g-1),this may induce a strong impact on the snow albedo in the last 46 years in our study *** indicate two periods with obviously high deposition concentrations(1955―1965 and 1974―1989) and two periods with low concentrations(1966―1973 and 1990―1995),as well as a recent increasing *** com-paring EC and SO42- concentration variations and deciphering OC/EC ratios recorded in the same ice core,we can judge roughly that the carbonaceous particles deposited in Muztagh Ata ice core were attributed to fossil fuel combustion sources.

关键词：冰层磁芯碳微粒物中国昆仑山

Age and genesis of the Shagou River terraces in eastern Qi-lian Mountains

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Chinese Science Bulletin 2001年第6期46卷 509-513页

作者： PAN Baotian wu guangjian WANG Yixiang LIU Zhigang GUAN Qingyu Department of Geography Lanzhou UniversityLanzhou 730000China Institute of Geography Chinese Academy of SciencesBeijing 100101China

The fluvial terrace sequence in eastern Qilian Mountains is a record of periodic uplift events of the Tibetan Plateau. Based on paleomagnetic dating, thermolumines-cence dating, radio carbon dating and loess-paleosol sequence on terraces, we preliminarily determine the ages of five major terraces of the Shagou River, northern side of the Qilian Mountains. The ages of five terraces were about 830, 418, 250,140 and 10 ka, respectively. Analysis on characteristics of terraces show that five major terraces were mainly tectonic genesis. Therefore, five major terraces recorded five strong rising events in the Qilian Mountains during the past 830 ka. The ages of those rising events are about the same as those terraces formation. Sub-terraces, constituting a main terrace, were perhaps mainly formed by climatic changes.

关键词： Tibetan Plateau Qilian Mountains terrace uplift.

Seasonal variations of dust record in the Muztagata ice cores

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Chinese Science Bulletin 2008年第16期53卷 2506-2512页

作者： wu guangjian YAO TanDong XU BaiQing TIAN LiDe LI Zhen DUAN KeQin Laboratory of Environment and Process on Tibetan Plateau Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China State Key Laboratory of Cryospheric Science Chinese Academy of Sciences Lanzhou 730000 China

Based on the oxygen isotope ratio and microparticle record in ice cores recovered at Mt. Muztagata, Eastern Pamirs, the seasonal variations of atmospheric dust have been reconstructed for the past four decades. High dust concentrations and coarser particle grains have the similar trend with oxygen iso- tope value. Our statistical results indicate that 50%―60% high dust concentration samples occur dur- ing the season with high oxygen isotope values (summer), while low dust storm frequency during spring and winter. Back-trajectory analysis shows that the air mass hitting Muztagata predominately came from West Asia (such as Iran-Afghanistan Plateau) and Central Asia, which are the main dust source area for Muztagata. Dust storms in those source areas most frequently occur during summer (from May to August), while frequent dust storm events in northern China mainly occur during spring (March to May). Regions in the path of Asian dust transport, such as in Japan, the North Pacific, and Greenland, also show high dust concentrations during spring (from March to May). Our results indicate that dust storms have different seasonality in different regions within Asia.

关键词：灰尘季节变化冰层氧同位素

Recent high-resolution glaciochemical record from a Dasuopu firn core of middle Himalayas

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Chinese Science Bulletin 2008年第3期53卷 418-425页

作者： WANG PengLing YAO TanDong TIAN LiDe wu guangjian LI Zhen YANG Wei Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China National Key Laboratory of Cryospheric Sciences Chinese Academy of Sciences Lanzhou 730000 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China

A 16.8 m firn core of middle Himalayas was recovered on the col of Dasuopu glacier in August 2006,being 7000 m above sea level.A total of 317 samples were measured for stable oxygen isotope ratios(δ18O)and major ion concentrations(Na+,NH4+,K+,Mg2+,Ca2+,Cl?,SO42?,and NO3?).The firn core dating and seasonal partitioning were carried out based on the marked seasonal variations along the stable oxygen isotopes and crustal species(Ca2+,Mg2+)*** multi-parameters and high-resolution glaciochemical data set of Dasuopu firn core recorded the detailed chemical characteristics of pre-cipitation in high-elevation region,middle Himalayas,since 1991 A.D.,which mainly originated from the crustal and anthropogenic sources,while the sea-salt contribution was *** seasonal variability of major ion concentrations was dominated by the seasonal alternation of the prevalent air mass,at-mospheric circulation situation and precipitation *** regression analysis indicated that most of the variance in annual ionic fluxes can be explained by a linear dependence on snow accumu-lation rate.

关键词：喜马拉雅山脉季节变化南亚季风冰川冰芯

2013―2022年山东省65岁及以上老年人肺结核流行特征及空间聚集性

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中华疾病控制杂志 2024年第2期28卷 131-137,170页

作者：代炳芹张艺馨孙晓英张吉玉吴光健曹杰孙成玺马吉祥山东省疾病预防控制中心业务管理部济南250014 山东省公共卫生临床中心统计科济南250101 山东省疾病预防控制中心济南250014

目的分析2013―2022年山东省65岁及以上老年人(老年人)肺结核流行特征及空间聚集性,为制定精准防控措施提供参考依据。方法通过中国疾病预防控制信息系统收集数据资料,采用描述性分析、Joinpoint回归分析及空间自相关分析方法分析老年... 详细信息

目的分析2013―2022年山东省65岁及以上老年人(老年人)肺结核流行特征及空间聚集性,为制定精准防控措施提供参考依据。方法通过中国疾病预防控制信息系统收集数据资料,采用描述性分析、Joinpoint回归分析及空间自相关分析方法分析老年人肺结核流行特征及空间聚集性。结果2013―2022年山东省共报告老年人肺结核病例76176例,年均发病率为59.09/10万,每年1―3月为发病高峰,以男性农民为主。Joinpoint回归分析显示,2013―2022年老年人肺结核报告发病率呈下降趋势,年度变化百分比为-8.92%(95%CI:-10.32%~-7.51%,P<0.05)。全局空间自相关分析结果显示,老年人肺结核报告发病率各年度Moran′s I指数为0.135~0.481(均P<0.05),提示存在空间聚集性。局部空间自相关分析结果显示,“高-高”聚集区主要集中在鲁西地区的的聊城市及鲁北地区的德州市和滨州市。结论山东省2013―2022年老年人肺结核发病率呈下降趋势,以男性农民为主,鲁西、鲁北等“高-高”聚集区需重点防控。

关键词：肺结核老年人流行特征空间自相关

Quick ice mass loss and abrupt retreat of the maritime glaciers in the Kangri Karpo Mountains, southeast Tibetan Plateau

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Chinese Science Bulletin 2008年第16期53卷 2547-2551页

作者： YANG Wei YAO TanDong XU BaiQing wu guangjian MA LingLong XIN XiaoDong Institute of Tibetan Plateau Research Chinese Academy of Sciences Beijing 100085 China National Key Laboratory of Cryospheric Science Chinese Academy of Sciences Lanzhou 730000 China Graduate University of the Chinese Academy of Sciences Beijing 100049 China

The maritime glaciers are sensitive to climate change because of high annual precipitation and high air temperature in the region. A combined comprehensive study was carried out based on glacier mass balance observation, GPS-based glacier terminus position survey, glacier Ground Penetrating Radar, topography maps and RS satellite images in the Kangri Karpo Mountains, Southeast Tibet. The study revealed a strong ice mass loss and quick glacier retreat since the 1970s. Ata Glacier, one glacier from the south slope of the Kangri Karpo Mountains, has formed a 6-km-long terminal moraine zone at the end of the glacier since the 1970s, and the accelerating retreat is largely due to the strong glacier sur- face melting. Mass balance study on the other four glaciers on the northern side of the Kangri Karpo Mountains shows that they are in large negative mass balance and the glaciers had retreated 15―19 m from May 2006 to May 2007. The in-situ glacier observation also shows that the glacier retreat is more obvious in small glaciers. The enhanced ice mass deficit caused by climate warming and the ongoing extinction of many small glaciers in this region could seriously affect the water resources, environ- ments, local climate and regional sustainable development in the near future.

关键词：西藏高原海上冰川山脉气候变化

年层自动识别方法在青藏高原冰芯定年中的应用

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冰川冻土 2024年第3期46卷 731-741页

作者：罗语晴姚檀栋徐柏青杨丹丹王理邬光剑李真王宁练曲冬梅武小波中国科学院青藏高原研究所青藏高原地球系统与资源环境重点实验室北京100101 中国科学院大学北京100049 兰州大学资源环境学院甘肃兰州730000 中国科学院西北生态环境资源研究院甘肃兰州730000 陕西省地表系统与环境承载力重点实验室陕西西安710127

冰芯是重建过去气候环境变化的良好载体,高时间分辨率冰芯信息的提取依赖于冰芯准确定年。本文结合人工定年与基于隐马尔科夫模型的年层自动识别算法,在青藏高原的作求普冰芯、达索普冰芯和阿尼玛卿冰芯上进行了测试、验证与分析。在约... 详细信息

冰芯是重建过去气候环境变化的良好载体,高时间分辨率冰芯信息的提取依赖于冰芯准确定年。本文结合人工定年与基于隐马尔科夫模型的年层自动识别算法,在青藏高原的作求普冰芯、达索普冰芯和阿尼玛卿冰芯上进行了测试、验证与分析。在约束参考层、同步其他冰芯记录及审核复盘时,该方法在一定程度上减少了人工逐层识别的时间,并能通过算法自动推断年层所在位置及提供误差范围。首先,由人工提供一套基础定年模板及约束点,随后基于算法学习模板,计算冰芯代理变量的准周期性的循环,找到目标段落并探究其年层存在的可能性,通过前向-后向算法寻找所有可能的年层点位,并通过最大似然法从中选出最优解。在年层自动识别算法辅助下的作求普、达索普冰芯上部δ^(18)O定年结果与已知年表的累计误差小于2 a(3%),具有较好的一致性。进一步将此方法应用于阿尼玛卿冰芯上部的定年,得出该算法与人工定年在e_(1)[2.07,4.47]、e_(2)[8.31,9.71]部分存在1~2 a的差异。再经污化层校正,冰芯56.48 m处的定年结果为74 a,误差范围±3 a。本文设计的方法结合了人工判定年层的优势与算法的标准化分层处理能力,降低了在年代校正过程中的人工参与,可为未来青藏高原地区高分辨率冰芯数年层方法定年的误差量化研究提供科学参考。

关键词：冰芯定年青藏高原年层自动识别算法(StratiCounter) 阿尼玛卿冰芯