检索结果-南通市图书馆

Phytolith records of the climate change since the past 15000 years in the middle reach of the Yangtze River in China

引用

Frontiers of Earth Science 2012年第1期6卷 10-17页

作者： Yansheng GU Hanlin WANG Xianyu huang Hongxia PENG junhua huang State Key Laboratory of Geobiology and Environmental Geology(BGEG) China University of GeosciencesWuhan 430074China Hubei Key Laboratory of Wetland Evolution&Eco-Restoration(WEER) China University of GeosciencesWuhan 430074China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China

Based on 14C dating and core sediments survey, phytolith records are employed to reconstruct paleovegetation and paleoclimate in the Jianghan Plain in the middle reach of the Yangtze River. Phytoliths identified are assigned into 21 well-described morphotypes and divided into four groups （Poaceae, fern, coniferous and broad-leaved）. The phytolith assemblages together with warmth index （Iw） are divided into 18 ecological zones, which reflect a complete vegetation history related to climate change in the middle reach of the Yangtze River during the past 15000 years. On the basis of the correlation ofphytolith records with the paleoclimatic indicators from stalagmite, peatland, North Atlantic deep-sea sediments, Loess Plateau of Central China, and Arabic Sea sediments, eight climatic phases are identified included Last Glacial Maximum （LGM）（20- 14.8 cal kaBP）, Last Deglaciation （LDG）（14.8-11.9 cal kaBP）, low-temperature phase in the Early Holocene （11.9-8 cal kaBP）, Holocene Opti- mum （8-4.9cal kaBP）, Holocene Katathermal （4.9- 1.1 cal kaBP）, Medieval Warmth Period （MWP）（1.1- 0.7 cal kaBP）, Little Ice Age （LIA）（0.7-0.15 cal kaBP）, and Modem Warming （0.15 cal kaBP-present）. Climatic events such as Bolling-Allerod warm intervals, Older Dryas, Inter-Allerod Cold Period, and Younger Dryas, and eight Holocene Bond events （B1-8） have been identified since the LDG. Our results demonstrate that the evolution of the climate in the research area has a strong link with the Indian Summer Monsoon （SW Monsoon）, Asian Summer Monsoon （SE Monsoon）, and Holocene events in North Atlantic simultaneously, which might indicate that solar variability affects the Earth surface climate system at the centennial and millennial scales.

关键词： core sediments middle reach of the YangtzeRiver 15000 years phytolith assemblages paleovegetation,paleoclimate

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Characterstics of seasonal variations of leaf n-alkanesand n-alkenes in modern higher plants in Qingjiang, Hubei Province, China

引用

Chinese Science Bulletin 2008年第17期53卷 2659-2664页

作者： CUI JingWei huang junhua XIE ShuCheng State Key Laboratory of Geological Processes and Mineral Resources China University of Geosciences Wuhan 430074 China Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of Geosciences Wuhan 430074 China

On the basis of GC and GC-MS analyses, the seasonal variation of leaf lipids is observed in five plant species in Qingjiang in Hubei Province. The CPI values (carbon preference index) of n-alkanes decrease gradually from May to November, though the carbon number distributions and the predominant carbon number in an individual species keep unchanged. The declined CPI values might be caused by the leaf fading, which is further supported by a comparison of the defoliated leaves with the fresh leaves. This observation infers the CPI values of n-alkanes in Quaternary sediments can be used as a tool to index the humification, and thus the climatic and the environmental conditions. The plants analyzed here show a remarkable difference in n-alkanes abundance, suggesting their differential contribution to the n-alkanes identified in sediments. The abundance and the compound species of the n-alkenes detected in the plant leaves change greatly with the seasons due to the influence of temperature, with the least compounds being identified in August.

关键词：环境变化 n-烷烃 n-烯烃平均碳链长度高等植物

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Optimization of acid digestion conditions on the extraction of fatty acids from stalagmites

引用

Frontiers of Earth Science 2012年第1期6卷 109-114页

作者： Canfa WANG Hongbin ZHANG Xianyu huang junhua huang Shucheng XIE State Key Laboratory of Biogeology and Environmental Geology China University of GeosciencesWuhan 430074China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China

Lipids in stalagmites have been shown the potential for the paleoclimate reconstruction. However, the low lipid content leads to the difficulty in gaining high resolution lipid record in stalagmites because large mass of samples are required. Previous studies have validated that the acid digestion can improve the yield of lipids, especially fatty acids （FAs） and 3-hydroxy fatty acids （3- OH-FAs）. In order to obtain more content of FAs and 3- OH-FAs with limited stalagmite sample weight, we investigate here how the acid digestion conditions （HC1 concentration, heating temperature and time duration） could affect the yields of FAs and 3-OH-FAs. Under different concentration of HC1, from 2.0 to 6.0 mol/L, the FAs keep the same step in content variation with 3-OH- FAs, and the highest yields of both two appeared under the 3 mol/L HCl. The content of 3-OH-FAs increases posi- tively with the heating temperature from 80℃ to 150℃, while FAs showed the highest content at 130℃. Both of FAs and 3-OH-FAs firstly increased to a high content and then decreased as the heating time duration varies from 1.0 to 4.0 h, with the highest yields of both two being at 3.0 h. Consequently, we suggest the optimized acid digestion condition is under 3 mol/L HC1, heating at 130℃ for 3 h and 5 g of each stalagmite sample are sufficient for the lipid analysis.

关键词： stalagmite lipids acid digestion optimization

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Carbon and oxygen isotopes suggesting deep-water basin deposition associated with hydrothermal events(Shangsi Section, Northwest Sichuan Basin-South China)

引用

Chinese Journal Of Geochemistry 2014年第1期33卷 77-85页

作者： CHEN Hui XIE Xi'nong MAO Kainan huang junhua Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education Faculty of Resources China University of Geosciences State Key Laboratory of Geological Processes and Mineral Resources Faculty of GeosciencesChina University of Geosciences

Carbon and oxygen isotope records for Shangsi Section in Northwest Sichuan Basin, South China can help investigating depositional environments and processes, including the burial rate and possible contribution of hydrothermal events. Samples from the lower Chihsian Formation show δ13CPDB and δ18OPDB values close to those of typical marine limestone. However, the overlying Permian middle-upper Chihsian, Wujiaping, and Maokou Formation samples reveal negative δ18OSMOW values and strong positive δ13CPDB values. These indicate high biological productivity and rapid burial of organic carbon. Samples from the Dalong Formation present both negative δ13CPDB and negative δ18OPDB values, which are quite different from the underlying Permian strata. These abnormal carbon and oxygen isotope characteristics in the Dalong Formation may suggest that hydrothermal processes contributed to deposition.

关键词：氧同位素记录盆地沉积四川盆地有机碳西北部热液活动中国二叠纪地层

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

A new paleoenvironmental index for anoxic events—Mo isotopes in black shales from Upper Yangtze marine sediments

引用

Science China Earth Sciences 2011年第7期54卷 1024-1033页

作者： ZHOU Lian SU Jie huang junhua YAN JiaXing XIE XiNong GAO Shan DAI MengNing Tonger State Key Laboratory of Geological Processes and Mineral Resources China University ofGeosciences Wuhan 430074 China Key Laboratory of Biogeology and Environmental Geology of Ministry of Education China University of Geosciences Wuhan 430074 China Key Laboratory of Tectonics and Petroleum Resources of Ministry of Education China University of Geosciences Wuhan 430074 China State Key Laboratory of Continental Dynamics Department of Geology Northwest University Xi'an 710069 China Wuxi Institute of Petroleum Geology China Petroleum & Chemical Corporation Wuxi 214151 China

This paper investigates the high-solution of Mo isotopes and uses trace-element analyses for fresh and representative black shales and siliceous shales collected from the transition between the Late Ordovician and the Early Silurian at the Wangjiawan section in Yichang and the Late Permian Dalong Formation in the Shangsi Section of Sichuan. The applicability of different geochemical parameters used as paleo-oxygenation indices are also compared. The preliminary results show that V/（V＋Ni）, Uauth （auth U）, V/Cr, Ceanom and U/Th have a scattered variation range, but most samples plot within the suboxic-anoxic fields. The suboxic-anoxic environment was dominant during the deposition and formation of the two anoxic facies. These redox indicators show little correspondence to the δ98M0 values. The U/Mo ratio can be used as a potential proxy for the paleo-redox conditions due to the possibility that Mo is enriched relative to U at different redox gradients during early diagenesis. This evidence is more significant for the euxinicity condition and corresponds to positive δ98M0 （〉1.5%o） values with low U/Mo ratios. This evidence is likely related to the depositional conditions near the boundary between anoxic and euxinic environ- ments, which are characterised by low bioturbation or water circulation. Other samples reveal a wide scatter of U/Mo ratios and δ98M0 〈1.5%0. These results are likely due to punctuated improvements in oxygenation with intense bioturbation or water circulation, which led to the redistribution of trace element.

关键词： molybdenum isotopes proxy for paleo-redox conditions black shale Upper Yangtze

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Geobiological approach to evaluating marine carbonate source rocks of hydrocarbon

引用

Science China Earth Sciences 2011年第8期54卷 1121-1135页

作者： YIN HongFu XIE ShuCheng YAN JiaXin HU ChaoYong huang junhua Tenger QIE WenKun QIU Xuan State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences Wuhan 430074 China State Key Laboratory of Geological Process and Mineral Resources China University of Geoscience Wuhan 430074 China Wuxi Institute of Petroleum Geology SINOPEC Wuxi 214151 China

Evaluating the pre-Jurassic marine source rocks in China has been difficult because these rocks are generally too highor over-maturated for most traditional methods to *** to the remaining parameter TOC (%),its lower limit for recognizing the carbonate source rocks in China has been in *** Phanerozoic sections in the Middle-Upper Yangtze Platform and the Guizhou-Hunan-Guangxi Basin have been studied in search for a different approach to complementing the traditional evaluation method for these source *** have applied a geobiological approach to tracing the organic carbon (OC) output and accumulation from the living stage (primary productivity) to the post-mortem deposited remains,and finally to the preserved burial *** biological and geological parameters are employed to represent the OC of the three stages.A series of proxies of these parameters are discussed and integrated to establish a geobiological evaluation system independent of TOC and other traditional *** we use the Guangyuan section in Sichuan as an example for the geobiological *** results indicate that in the argillaceous rocks,the geobiological parameters show the qualified source rocks in accordance with high TOC values;but in the carbonates,the good source rocks delineated by the geobiological parameters have a wide range of TOC,from 0.03% to 1.59%,mostly<0.3%.We suggest that it is still premature to set TOC=0.3% or 0.5% as the lower limit for the pre-Jurassic carbonate source rocks in South China.

关键词： geobiological evaluation carbonate source rocks parameters proxies

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

The fluctuating environment associated with the episodic biotic crisis during the Permo/Triassic transition:Evidence from microbial biomarkers in Changxing,Zhejiang Province

引用

Science China Earth Sciences 2007年第7期50卷 1052-1059页

作者： huang XianYu JIAO Dan LU LiQiang XIE ShuCheng huang junhua WANG YongBiao YIN HongFu WANG HongMei ZHANG KeXin LAI XuLong Key Laboratory of Biogeology and Environmental Geology Ministry of Educationand the State Key Laboratory of GPMRChina University of GeosciencesWuhan 430074China Faculty of Material Science and Chemical Engineering China University of GeosciencesWuhan 430074China School of Environmental Studies China University of GeosciencesWuhan 430074China

The environmental conditions and the biotic crisis during the Permo-Triassic (Tr/P) transition received increasing attention in the past decades. Presented herein are the molecular fossil records of cyano-bacteria and green sulfur bacteria,the base of the marine ecosystem,to highlight the episodic nature of both the environment and the biotic crisis during this critical period. At least two episodes of cyano-bacterial expansion are documented by 2-methylhopanes ranging from C28 to C32 in carbon number,indicative of the instable marine ecosystem and the fluctuant aquatic nutrients. Meanwhile,the index of 2-alkyl-1,3,4-trimethylbenzenes (biomarkers of green sulfur bacteria) and the ratio of pristane to phy-tane (Pr/Ph) witness the fluctuation of sedimentary environmental redox conditions. The above mo-lecular evidence suggests the occurrence of highly fluctuating environmental conditions during the Tr/P transition,which is consistent with,and probably the cause of,the multi-phased biotic crisis and the prolonged faunal recovery.

关键词： cyanobacteria green sulfur bacteria molecular fossil Tr/P transition environment

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Flexible, Transparent and Conductive Metal Mesh Films with Ultra‑High FoM for Stretchable Heating and Electromagnetic Interference Shielding

引用

Nano-Micro Letters 2024年第5期16卷 201-213页

作者： Zibo Chen Shaodian Yang junhua huang Yifan Gu Weibo huang Shaoyong Liu Zhiqiang Lin Zhiping Zeng Yougen Hu Zimin Chen Boru Yang Xuchun Gui State Key Laboratory of Optoelectronic Materials and Technologies School of Electronics and Information TechnologySun Yat-Sen UniversityGuangzhou 510275People’s Republic of China Guangdong Provincial Key Laboratory of Materials for High Density Electronic Packing Shenzhen Institutes of Advanced TechnologyChinese Academy of SciencesShenzhen 518055GuangdongPeople’s Republic of China School of Materials Science and Engineering Sun Yat-Sen UniversityGuangzhou 510275People’s Republic of China

Despite the growing demand for transparent conductive films in smart and wearable electronics for electromagnetic interference(EMI)shielding,achieving a flexible EMI shielding film,while maintaining a high transmittance remains a significant ***,a flexible,transparent,and conductive copper(Cu)metal mesh film for EMI shielding is fabricated by self-forming crackle template method and electroplating *** Cu mesh film shows an ultra-low sheet resistance(0.18Ω□^(-1)),high transmittance(85.8%@550 nm),and ultra-high figure of merit(>13,000).It also has satisfactory stretchability and mechanical stability,with a resistance increases of only 1.3%after 1,000 bending *** a stretchable heater(ε>30%),the saturation temperature of the film can reach over 110°C within 60 s at 1.00 V applied ***,the metal mesh film exhibits outstanding average EMI shielding effectiveness of 40.4 dB in the X-band at the thickness of 2.5μ*** a demonstration,it is used as a transparent window for shielding the wireless communication electromagnetic ***,the flexible and transparent conductive Cu mesh film proposed in this work provides a promising candidate for the next-generation EMI shielding applications.

关键词： Metal mesh Transparent conductive film Stretchable heater Electromagnetic interference shielding

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Post-traumatic stress disorder status in a rescue group after the Wenchuan earthquake relief

引用

Neural Regeneration Research 2013年第20期8卷 1898-1906页

作者： junhua huang Qunying Liu Jinliang Li Xuejiang Li Jin You Liang Zhang Changfu Tian Rongsheng Luan Department of Epidemiology Huaxi Public Health School of Sichuan University Yunnan General Hospital of the Chinese People's Armed Police Forces Department of Psychological Counseling Yunnan General Hospital of the Chinese People's Armed Police Forces Department of Psychological Counseling Sichuan General Hospital of the Chinese People's Armed Police Forces Department of Infectious Diseases First Affiliated Hospital of Kunming Medical College Kunming Center for Disease Control Scientific Research and Experimental Center Kunming Medical College

Previous studies have suggested that the incidence of post-traumatic stress disorder in earthquake rescue workers is relatively high. Risk factors for this disorder include demographic characteristics, earthquake-related high-risk factors, risk factors in the rescue process, personality, social support and coping style. This study examined the current status of a unit of 1 040 rescue workers who participated in earthquake relief for the Wenchuan earthquake that occurred on May 12th, 2008. Post-traumatic stress disorder was diagnosed primarily using the Clinician-Administered Post-traumatic Stress Disorder Scale during structured interviews. Univariate and multivariate sta-tistical analyses were used to examine major risk factors that contributed to the incidence of post-traumatic stress disorder. Results revealed that the incidence of this disorder in the rescue group was 5.96%. The impact factors in univariate analysis included death of family members, contact with corpses or witnessing of the deceased or seriously injured, near-death experience, severe injury or mental trauma in the rescue process and working at the epicenter of the earthquake. Correlation analysis suggested that post-traumatic stress disorder was positively correlated with psychotic and neurotic personalities, negative coping and low social support. Impact factors in mul-tivariate logistic regression analysis included near-death experience, severe injury or mental trauma, working in the epicenter of the rescue, neurotic personality, negative coping and low social support, among which low social support had the largest odds ratio of 20.42. Findings showed that the oc-currence of post-traumatic stress disorder was the result of the interaction of multiple factors.

关键词： neural regeneration post-traumatic stress disorder incidence Wenchuan earthquake rescue groups influencing factor coping style personality social support cross-sectional investigation risk factors neuroregeneration

来源：

维普期刊数据库

同方期刊数据库评论

在线全文

学校读者我要写书评

暂无评论

Molybdenum Concentration and the Risk of Spontaneous Preterm Birth: A Nested Case-Control Study — Beijing Municipality, China, 2018–2020

引用

China CDC weekly 2024年第13期6卷 261-266,I0005,I0006页

作者： junhua huang Wei Zheng Aili Wang Weiling Han Junxi Chen Hang An Lailai Yan Zhiwen Li Guanghui Li Division of Endocrinology and Metabolism Department of ObstetricsBeijing Obstetrics and Gynecology HospitalCapital Medical University.Beijing Maternal and Child Health Care HospitalBeijingChina Department of Obstetrics and Gynecology Beijing Luhe HospitalCapital Medical UniversityBeijingChina Institute of Reproductive and Child Health National Health Commission Key Laboratory of Reproductive HealthPeking UniversityBeijingChina Department of Epidemiology and Biostatistics School of Public HealthPeking UniversityBeijingChina Department of Laboratorial Science and Technology School of Public HealthPeking UniversityBeijingChina

What is already known about this topic?The level of molybdenum(Mo)in a mother’s urine has been linked to the growth rate of the fetus and the blood pressure levels in *** is added by this report?We evaluated the variations in maternal plasma Mo concentrations throughout pregnancy and their potential association with the risk of spontaneous preterm birth(SPB).What are the implications for public health practice?Future research must determine the Mo levels in pregnant women across various regions in ***,particular attention needs to be given to the potential increase in Mo concentration throughout pregnancy and its possible adverse impacts on the health of both the mother and the fetus.

关键词： mother urine pregnancy

来源：

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

欢迎您,

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案：

请选择收藏分类：

通借通还

欢迎您,

建议与咨询 留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

时间限定

文献类型

馆藏选择

核心期刊

语言

文献类型

帮助

文字说明：

检索规则说明：

检索范例：

分类表

所选分类

限定检索结果

文献类型

馆藏范围

日期分布

学科分类号

主题

机构

作者

语言

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

在线全文

请选择保存的检索档案： 新增检索档案 确定 取消

请选择收藏分类： 新增自定义分类 确定 取消

通借通还

建议与咨询留下您的常用邮箱和电话号码，以便我们向您反馈解决方案和替代方法

请选择保存的检索档案：

请选择收藏分类：