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Spatiotemporal evolution of C3/C4 vegetation and its controlling factors in southern China since the last glacial maximum

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Science China Earth Sciences 2019年第8期62卷 1256-1268页

作者： Linlin CUI jianfang hu Xu WANG Institute of Geology and Geophysics Chinese Academy of SciencesBeijing100029China Key Laboratory of Cenozoic Geology and Environment Institute of Geology and GeophysicsChinese Academy of SciencesBeijing100029China Guanzhou Institute of Geochemistry Chinese Academy of SciencesBeijing510640China

To date, few research have been reported on the evolution of C3/C4 vegetation in southern China, and the main mechanism influencing the evolution of C3/C4 vegetation is unclear. That makes it difficult for researchers to understand the competition mechanism of C3 and C4 plants under different climate environments and its relationship with the climate factors. It is also not conducive for researchers to assess the influence of future climate change on regional C3/C4 vegetation. Exactly, C3/C4 vegetation change in the regional-scale will have a significant impact on the global carbon cycle and agricultural ***, it is especially important to reconstruct the evolutionary history of C3/C4 vegetation in southern China and clarify the influencing mechanism of climate change. In this study, we systematically analyzed stable carbon isotope(δ13 C) of the longchain n-alkanes in sediment samples from eight lakes and four peat profiles in southern China, to reconstruct the spatiotemporal evolution of C3/C4 vegetation in these regions since the Last Glacial Maximum(LGM) and to investigate the climate factors that affect the C4 plant abundance change in the research area. The integrated long-chain n-alkane(C27–C33) stable carbon isotope results of samples from Zhanjiang huguangyan Maar Lake, Xingyun Lake, Lugu Lake and Dingnan peat showed that, from the LGM to the Early Holocene, C4 plant relative abundance exhibited a gradually increasing trend from 21% to 34%. In the Middle Holocene, the C4 plant abundance significantly declined and reached a lowest value of 10%. In space, the C4 plant abundance generally exhibited a gradually declining trend from south to north in the LGM and the Early Holocene, while it showed an opposite trend in the Holocene Climate Optimum(6.0 cal ka BP). It reflected that the main influencing factor on C4 plants spatial distribution was changing from temperature to precipitation. This study indicated that temperature was the dominant facto

关键词： Stable carbon isotope Long-chain n-alkanes C3/C4vegetation Last Glacial Maximum Holocene Climate Optimum period

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Branched glycerol dialkyl glycerol tetraethers and paleoenvironmental reconstruction in Zoigê peat sediments during the last 150 years

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Chinese Science Bulletin 2011年第23期56卷 2456-2463页

作者： ZHOU HaoDa hu jianfang MING LiLi PENG PingAn ZHANG Gan Guangzhou Institute of Geochemistry Chinese Academy of Sciences Guangzhou 510640 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Branched glycerol dialkyl glycerol tetraethers (GDGTs) were analyzed in peat samples taken from the Zoigê grassland, located on the eastern margin of the Qinghai-Tibetan Plateau. The mean annual air temperature (MAAT) and pH in the 210 Pb-dating peat core were reconstructed based on the cyclization of branched tetraethers (CBT) and methylation of branched tetraethers (MBT) indices for the last 150 years. The results showed that the MAAT and pH values involved three stages of variation over the last 150 years. The pH was stable and the MAAT decreased slowly by about 1°C from 1851 to 1927. The pH decreased rapidly by 0.6 and the MAAT decreased significantly by 2.5°C between 1927 and 1979. The pH and MAAT increased by 0.8 and 5°C, respectively, since the 1980s. The reconstructed temperatures correspond well to the mean winter temperatures reconstructed using tree-rings from the Jiuzhaigou Valley, situated at the boundary between the Qinghai-Tibetan Plateau and the Sichuan Basin. The estimated MAAT was similar to the temperatures reconstructed using tree-rings, indicating an increasing trend, as shown by local instrumental records from 1957 to 2001. These results provide further confidence in the application of proxies based on glycerol dialkyl glycerol tetraethers in peat records for continental paleoclimate reconstruction.

关键词：泥炭记录二烷基甘油精神古环境沉积物青藏高原东缘空气温度

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Determination of linear alkylbenzenesulfonates in modern sediments from core Zhu-9 and its significance

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Chinese Science Bulletin 2000年第S1期45卷 80-85页

作者： jianfang hu Ping’an Peng Yushun Min Guoying Sheng Jiamo Fu Chinese Acad Sci Guangzhou Inst Geochem State Key Lab Organ Geochem Guangzhou 510640 Peoples R China

High performance liquid chromatography (HPLC) has the advantages of rapid analysis and high sensitivity. In the present study a suitable analytical condition has been established for HPLC, and the LAS in modern sediments from core Zhu-9 at the Pearl River mouth has been determined by HPLC. The concentrations of C12-LAS homologues are the highest. The sedimentation flux of C12-LAS was correlated with the average flow of the Xijiang and Beijiang rivers: the higher the flow rate, the larger the C12-LAS sedimentation flux. This shows that the more rapidly the river flows, the shorter the LAS will stay in freshwater, the less the extent of biodegradation, the larger the C12-LAS sedimentation flux in the core Zhu-9.

关键词： high performance liquid chromatography (HPLC) Pearl River mouth modern sediment linear alkylbenz- enesulfonates (LAS) sedimentation flux annual average flow.

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Reconstruction of surface ocean water pCO_(2(aq)) in Nansha area,the South China Sea during the last 30 ka

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Chinese Science Bulletin 2003年第2期48卷 199-203页

作者： hu jianfang JIA Guodong PENG Ping FANG Dianyong ZHAO Quanhong State Key Laboratory of Organic Geochemistry Guangzhou Institute of Gcochemistry. Chinese Academy of Sciences Guangzhou 510640 China Laboratory of Marine Geology Tongji University Shanghai 200092ChinaademyofSciencesGuangzhou 510640China

The reconstruction of pCO2 in the tropic ocean is one of the most important issues to understand global cli-matic changes. In this study, the high-resolution strati-graphic analysis of core 17962 was conducted, which is lo-cated in the southern South China Sea (SCS). The contents of sedimentary organic matter, the stable carbon isotopic composition of sedimentary organic matter, and the d 13C values of black carbon and terrigenous n-alkanes were de-termined. And the d 13Cwc value of carbon derived from aquatic was calculated. On the basis of d 13Corg-pCO2 equa-tion proposed by Popp et al. (1989), we estimated the pCO2 in the Nansha area, SCS, since the last glaciation using d 13Cwc instead of d 13Corg. The results show that the average pCO2 was estimated at 240 ppmV during the last glaciation, and at 320 ppmV in the Holocene. A comparison of surface sea pCO2 with the atmosphere CO2 recorded in the Vostok ice core, indicates that CO2 in surface water of the southern SCS could emit into atmosphere during the last 30 ka.

关键词：南海南沙地区表层海水古二氧化碳分压全新世 pCO2 重建晚冰河期热带海洋

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Low-latitude hydroclimate changes related to paleomagnetic variations during the Holocene in coastal southern China

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Frontiers of Earth Science 2024年第2期18卷 324-335页

作者： Tingwei ZHANG Xiaoqiang YANG Jian YIN Qiong CHEN jianfang hu Lu WANG Mengshan JU Qiangqiang WANG School of Earth Science and Engineering/Guangdong Provincial Key Laboratory of Geodynamics and Geohazards/Southern Marine Science and Engineering Guangdong Laboratory(Zhuhai)Sun Yat-sen UniversityGuangzhou 510275China Institute of Cultural Heritage Shandong UniversityQingdao 266237China State Key Laboratory of Organic Geochemistry Guangzhou Institute of GeochemistryChinese Academy of SciencesGuangzhou 510640China College of Urban and Environmental Sciences Peking UniversityBeijing 100871China Institute of Oceanology Chinese Academy of SciencesQingdao 266071China

The variations in precipitation have displayed a complex pattern in different regions since the *** formation processes may have a significant impact on precipitation,especially during the tropical marine processes and summer monsoon which convey abundant water vapor to coastal southern China and inland ***,we use two 7500 year sedimentary records from the Pearl River Delta and the closed Maar Lake,respectively,in coastal southern China to reconstruct the mid-to-late-Holocene humidity variability and explore its possible relationship with cloud cover modulated by the Earth’s magnetic fields(EMF).Our proxy records document an apparent increase in wetness in coastal southern China between 3.0 and 1.8 kyr *** apparent increase in humidity appears to be consistent with the lower virtual axial dipole moments and,in turn,with a lower *** correlation suggests that the EMF might have been superimposed on the weakened monsoon to regulate the mid-to-late-Holocene hydroclimate in coastal southern China through the medium of galactic cosmic rays,aerosols,and cloud ***,further investigations are needed to verify this interaction.

关键词： hydroclimate variations Earth’s magnetic field coastal southern China the Holocene epoch

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Use of brGDGTs in surface geochemical exploration for petroleum —A case study of oil and gas fields in the Jiyang depression

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Science China Earth Sciences 2014年第6期57卷 1605-1612页

作者： ZHOU HaoDa hu jianfang XIONG YongQiang LIANG QianYong State Key Laboratory of Organic Geochemistry Guangzhou Institute of Geochemistry Chinese Academy of Sciences Graduate University of Chinese Academy of Sciences Zhuhai Central Station of Marine Environmental Monitoring State Oceanic Administration

Branched glycerol dialkyl glycerol tetraethers(brGDGTs),likely produced by bacteria in soil and peat,are widely distributed,easily detected,newly adopted biomarker *** this study,brGDGTs were used to explore the relationship between the absolute abundance of brGDGTs and the distribution of oil and gas fields in the Duoshiqiao area of the Jiyang *** results showed that the concentrations at the Xiakou fault and in the oil and gas fields were obviously higher than those in the contrast *** clear relationship among the concentration of brGDGTs,the distribution of oil and gas fields,and the acidolysis hydrocarbon(ethane)indicates that the concentration effectively responds to hydrocarbon seeps from the oil and gas field *** may become some of the most important indicators in surface geochemical prospecting for oil and gas.

关键词： brGDGTs Jiyang depression surface seep geochemical exploration petroleum

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Surface Modification of Medical Polyurethane by Plasma Treatment

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Chinese Physics Letters 1992年第2期9卷 79-82页

作者： LI Dejun ZHAO Jie GU Hanqing LU Mozhu DING Fuqing hu jianfang Department of Physics Tianjin Normal UniversityTianjin 300074 Tianjin Uretie Surgery Institute Tianjin 300076 Department of Physics Central National CollegeBeijing 100081

The wettability and surface structure of plasma treatment on medical polyurethane were *** kinds of gas,N_(2),Ar,were used to create the dow-temperature plasma under low *** wettability was investigated by means of the sessile drop method using water,the results show that the contact angle of water decreases from 78.8°to 61.9°as the treatment time *** results of electron spectroscopy for chemical analysis indicate that original chemical bonds were broken up after plasma,treatment,which was the main reason for the surface *** same time,the results of electron spinning resonance show that the amounts of radicals did not increase significantly after treatment,which is advantageous to clinical practice of polyurethane.

关键词： treatment spinning polyurethane

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Roles of a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism in ABA signal production in Arabidopsis

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Chinese Science Bulletin 2007年第4期52卷 484-491页

作者： REN huiBo FAN YiJian GAO Zhihui WEI KaiFa LI GuiFen LIU Jing CHEN Lin LI BingBing hu jianfang JIA WenSuo State Key Laboratory of Plant Biochemistry College of Agronomy and Biotechnology China Agricultural University Beijing 100094 China

ABA, acting as a stress signal, plays crucial roles in plant resistance to water stress. Because ABA signal production is based on ABA biosynthesis, the regulation of NCED, a key enzyme in the ABA biosynthesis pathway, is normally thought of as the sole factor controlling ABA signal production. Here we demonstrate that ABA catabolism in combination with a synergistic regulation of ABA biosynthesis plays a crucial role in governing ABA signal production. Water stress induced a significant accumulation of ABA, which exhibited different patterns in detached and attached leaves. ABA catabolism followed a temporal trend of exponential decay for both basic and stress ABA, and there was little difference in the catabolic half-lives of basic ABA and stress ABA. Thus, the absolute rate of ABA catabolism, i.e. the amount of ABA catabolized per unit time, increases with increased ABA accumulation. From the dynamic processes of ABA biosynthesis and catabolism, it can be inferred that stress ABA accumulation may be governed by a synergistic regulation of all the steps in the ABA biosynthesis pathway. Moreover, to maintain an elevated level of stress ABA sustained activation of NCED3 should be required. This inference was supported by further findings that the genes encoding major enzymes in the ABA biosynthesis pathway, e.g. NCED3, AAO3 and ABA3 were all activated by water stress, and with ABA accumulation progressing, the expressions of NCED3, AAO3 and ABA3 remained activated. Data on ABA catabolism and gene expression jointly indicate that ABA signal production is controlled by a sustained activation of NCED3 and the synergistic regulation of ABA biosynthesis and catabolism.

关键词：拟南芥 ABA信号 ABA生物合成分解代谢协同调节 NCED3 持续致活水胁迫干旱

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涤纶异收缩混纤丝仿毛闪光呢的设计与生产

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上海纺织科技 2018年第7期46卷 41-42,47页

作者：胡建芳无锡工艺职业技术学院

以涤纶异收缩混纤丝并捻纱为主要原料,在纬向嵌织部分聚酯银丝薄片,开发出一种仿毛闪光呢。介绍了涤纶异收缩混纤丝的特点及涤纶仿毛闪光呢的产品设计过程。重点对产品的倍捻、蒸纱定形、分条整经、剑杆织造及后整理等关键工序的工艺与... 详细信息

以涤纶异收缩混纤丝并捻纱为主要原料,在纬向嵌织部分聚酯银丝薄片,开发出一种仿毛闪光呢。介绍了涤纶异收缩混纤丝的特点及涤纶仿毛闪光呢的产品设计过程。重点对产品的倍捻、蒸纱定形、分条整经、剑杆织造及后整理等关键工序的工艺与技术措施作了分析与研讨。结果显示,所设计的产品具有闪光效果。

关键词：涤纶异收缩混纤丝仿毛织物闪光呢产品设计生产技术

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磁场对PET表面碳氟等离子体改性的影响Ⅱ.磁场位形与PET表面改性的关系

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高分子材料科学与工程 1999年第6期15卷 79-81页

作者：张亮王建祺胡建芳北京大学物理系介观物理国家重点实验室北京100871 北京理工大学化工与材料学院国家阻燃材料研究实验室北京100081 中央民族大学物理系北京100081

研究了不同磁场条件下碳氟等离子体对涤纶（ＰＥＴ）表面改性的影响，通过变角Ｘ光电子能谱（ＸＰＳ）方法研究改性后ＰＥＴ表面结构和性质的变化，并探讨了磁场对碳氟等离子体改性的影响。实验结果表明，在磁场存在的条件下，碳氟等离... 详细信息

研究了不同磁场条件下碳氟等离子体对涤纶（ＰＥＴ）表面改性的影响，通过变角Ｘ光电子能谱（ＸＰＳ）方法研究改性后ＰＥＴ表面结构和性质的变化，并探讨了磁场对碳氟等离子体改性的影响。实验结果表明，在磁场存在的条件下，碳氟等离子体处理ＰＥＴ的表面结构和性质的变化，依赖于磁场的强度而不是磁场的分布；磁场强度的增强，导致了改性后ＰＥＴ表面Ｆ／Ｃ比的提高及等离子体聚合或刻蚀程度的加强。

关键词：碳氟等离子体磁场聚合刻蚀 PET 改性 XPS

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