检索结果-南通市图书馆

Biogenic carbonate formation and sedimentation in the Xisha Islands: evidences from living Halimeda

Acta Oceanologica Sinica 2015年第4期34卷 62-73页

作者： XU Hong ZHAO Xinwei EBERLI G.P. LIU Xinyu ZHU Yurui CAI ying LUO Wei yan Guijing ZHANG Bolin WEI Kai SHI Jian Key Laboratory of Marine Hydrocarbon Resources and Environment Geology Qingdao Institute of Marine GeologyMinistry of Land and Resources School of Earth Sciences and Resources China University of Geosciences Comparative Sedimentology Laboratory University of Miami Zhanjiang Branch of China National Offshore Oil Corporation (CNOOC) Limited College of Energy Resouces Chengdu University of Technology

A recent island survey reveals that the Xuande Atoll and the Yongle Atoll in the Xisha Islands can be classified into one of two systems：the depleted atoll system and growth atoll system;the survey also indicates that the decreased area of several shoals is an unbearable burden for the Xisha Islands, of which the largest island area is 2.13 km2 and the minimum elevation is 1.4 m. According to a survey on the ecological characteristics of Halimeda in the Laolongtou breaker zone of Shidao Island in the Xisha Islands, the green and white living Halimeda are collected, the isotopic ages of 14C contained in the Halimeda are shown to be 27 years and 55 years, respectively, and carbonate mainly occurs in five types, i.e., luster, segment, sand, sand grain, and marl in the formation. The Halimeda segments mainly provide the carbonate sediments of long-term biogenic deposits in the reef environment and the annual productivity per area is 60–100 g/m2;the characteristics of the microstructure of the Halimeda are analyzed, the aragonite raphide carbonate is deposited and enriched in the cortexes, medullas and cysts, and the Halimeda generally contain major elements such as C, O, Ca, Cl, Mg, K, Na, S and Al, and are rich in trace elements such as tellurium （Te）, rhodium （Rh） and strontium. It is believed that the Halimeda grow slowly, including the biotic community of reef corals in the reef areas, thus they possess an environmental remediation capacity, but it takes much time to remedy the environment, and it is necessary to make the law to protect the diversity and vulnerability of the Xisha marine ecology, the ecology of the reef community and the island environment in a scientific way. As indicated in the survey, under the background of global warming and sea-level rise, the discovery of large amounts of Halimeda in the Laolongtou sea area is significant for the natural increase of the depleted atoll system of the Xuande Atoll, while the Halimeda segments represent the prima

关键词： Xisha Islands Halimeda composition of biogenic carbonate 14^C accelerator mass spectrometrydating segment aragonite raphide trace elements

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

Coons曲面结合B样条拟合大型面天线变形反射面

引用

电子与信息学报 2008年第1期30卷 233-237页

作者：王从思段宝岩仇原鹰西安电子科技大学机电工程学院西安710071

为了精确反映变形反射面实际形状,该文提出了一种新的分块拟合方法。该方法首先对变形反射面进行分环分块划分,再对每个块域分别进行Coons曲面拟合,并采用周向三次与径向二次B样条曲线来确定块域的边界条件,进而得到准确的反射面变形整... 详细信息

为了精确反映变形反射面实际形状,该文提出了一种新的分块拟合方法。该方法首先对变形反射面进行分环分块划分,再对每个块域分别进行Coons曲面拟合,并采用周向三次与径向二次B样条曲线来确定块域的边界条件,进而得到准确的反射面变形整体和局部信息。通过对不同情况下某16m天线的机电性能综合分析,证明了此方法是准确、有效的。

关键词：变形面天线分块拟合 Coons曲面 B样条曲线增益损失

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

Shifts in chemical and microbiological properties belowground of invader Ageratina adenophora along an altitudinal gradient

引用

Journal of Plant Ecology 2022年第3期15卷 561-570页

作者： Wei-Tao Li Yu-Long Zheng Rui-Fang wang Zheng-ying wang yan-Mei Liu Xiong Shi Zhi-Yong Liao yang-Ping Li Yu-Long Feng CAS Key Laboratory of Tropical Forest Ecology Xishuangbanna Tropical Botanical GardenChinese Academy of SciencesMengla 666303China Center of Conservation Biology Core Botanical GardensChinese Academy of SciencesMengla 666303China College of Life Sciences University of Chinese Academy of SciencesBeijing 100049China College of Agriculture and Forestry Puer UniversityPuer 665000China College of Bioscience and Biotechnology Liaoning Key Laboratory for Biological Invasions and Global ChangesShenyang Agricultural UniversityShenyang 110866China

Tropical mountain ecosystems are usually colonized by numerous invasive plant species and represent an ideal‘natural laboratory’to study the effects of altitude on plant *** aim of this study was to investigate the soil chemical and microbiological properties along an altitudinal gradient on a mountain colonized by the invader Ageratina *** soil of *** was collected over an altitudinal gradient(1400–2400 m)in Ailao Shan,*** determined soil organic carbon(C),nutrient contents,enzyme activities,bacterial community composition as well as C and nitrogen(N)contents of the plant *** stoichiometric indices were calculated to estimate the relative C,N or P limitations of the microbial *** was a significant effect of altitude on soil organic C in the rhizosphere,and a turning point in these measured variables was detected at an altitude of 2000 *** low elevations,the rapid growth of invasive plants depleted the deficient phosphorus(P)in tropical soils,leading to microbial P limitation;at high elevations,microbes invested more energy to obtain C from resistant litter,leading to microbial C *** beta diversity and soil pH contributed most to the altitudinal differences in ecoenzymatic stoichiometry,and Proteobacteria and Acidobacteria were the dominant bacterial phyla that determined the nutrient uptake status of *** results demonstrate how microbial nutrient acquisition belowground of *** along an altitudinal gradient,which could contribute to further knowledge about the effects of altitude on biological invasion.

关键词： Ageratina adenophora nutrients ecoenzymatic stoichiometry microbial metabolic limitation bacterial community

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

Ni47Ti44Nb9形状记忆合金冷轧管材的组织、织构和相变

引用

金属学报 2008年第2期44卷 139-144页

作者：颜莹金伟曹名洲东北大学材料物理与化学研究所沈阳110004 中国科学院金属研究所沈阳110016

利用OM、DSC和XRD,研究了Ni_(47)Ti_(44)Nb_9合金热锻棒、热挤压管材和不同热处理条件下冷轧管材的组织、织构和相变.结果表明:热锻棒中的B2相呈较宽的纤维状,主要织构接近{112}〈111〉和{123}〈111〉;热挤压管材纤维组织变细且发生碎化... 详细信息

利用OM、DSC和XRD,研究了Ni_(47)Ti_(44)Nb_9合金热锻棒、热挤压管材和不同热处理条件下冷轧管材的组织、织构和相变.结果表明:热锻棒中的B2相呈较宽的纤维状,主要织构接近{112}〈111〉和{123}〈111〉;热挤压管材纤维组织变细且发生碎化,多数晶粒的取向靠近{111}〈UVW〉;冷轧管材的B2相纤维组织发生严重碎化,抑制了冷却过程中马氏体相变的进行,{111}〈110〉和{112}〈110〉成为主要织构.随淬火温度的升高,冷轧管材硬度下降,M_s和A_s点升高,热滞减小.冷轧管材经600℃/90 min退火,{111}〈110〉和{112}〈110〉织构显著增强,经850℃退火,再结晶晶粒明显长大,M_s点显著提高,热滞和硬度下降,晶粒取向偏离{111}〈110〉和{112}〈110〉.

关键词： Ni47Ti44Nb9形状记忆合金冷轧管组织织构相变

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

婴幼儿配方乳粉及婴幼儿米粉中的蜡样芽胞杆菌流行情况、耐药性及分子特征研究

引用

食品安全质量检测学报 2024年第5期15卷 77-84页

作者：陈丽雯黄宝莹严家俊张娟綦艳周臣清周佺郑兰娟蒋爱民吴炜亮南方医科大学公共卫生学院食物安全与健康研究中心广东省热带病研究重点实验室广州510515 国家食品质量监督检验中心(广东) 广东省食品生物危害因素检测工程技术研究中心广东产品质量监督检验研究院佛山528300 华南农业大学食品学院畜禽产品精准加工与安全控制技术国家地方联合工程研究中心广州510642 广州市食品药品审评中心广州510410 浙江农业商贸职业学院农业经济管理系绍兴312000

目的了解流通环节市售婴幼儿配方乳粉和婴幼儿米粉中的蜡样芽胞杆菌流行情况、抗生素耐药性和毒力基因等分子特征。方法采用GB4789.14—2014《食品安全国家标准食品微生物学检验蜡样芽胞杆菌检验》对样品中的蜡样芽胞杆菌进行检测与... 详细信息

目的了解流通环节市售婴幼儿配方乳粉和婴幼儿米粉中的蜡样芽胞杆菌流行情况、抗生素耐药性和毒力基因等分子特征。方法采用GB4789.14—2014《食品安全国家标准食品微生物学检验蜡样芽胞杆菌检验》对样品中的蜡样芽胞杆菌进行检测与生化鉴定。进一步通过抗生素敏感实验和全基因组测序对11株代表性分离株进行研究,获得耐药表型及耐药、毒力基因等分子特征信息。结果婴幼儿配方乳粉和婴幼儿米粉中蜡样芽胞杆菌的检出率分别为11.97%(56/468)和20.74%(28/135)。11株代表性蜡样芽胞杆菌均为多重耐药菌株,全基因组测序结果发现11株分离株共携带8个耐药基因和14个毒力基因,其中主要携带磷霉素、β-内酰胺类抗生素抗性基因,以及肠毒素基因(hbl和nhe),另发现1株携带ces基因簇蜡样芽胞杆菌菌株。多位点序列分型表明,11株分离株具有遗传多样性,分属10个ST型。结论婴幼儿配方乳粉和婴幼儿米粉中的蜡样芽胞杆菌检出率较低,但代表菌株的耐药谱和遗传特征具有多样性,应进一步加强监测及采取有效措施进行控制,以保障相关食品的安全性。

关键词：蜡样芽胞杆菌全基因组测序抗生素抗性多重耐药毒力因子

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

Radiofrequency ablation or microwave ablation combined with transcatheter arterial chemoembolization in treatment of hepatocellular carcinoma by comparing with radiofrequency ablation alone

引用

Chinese Journal of Cancer Research 2014年第1期26卷 112-118页

作者： Yongxiang Yi Yufeng Zhang Qiang Wei Liang Zhao Jianbo Han yan Song ying Ding Guilan Lu Junmao Liu Huaiying Ding Feng Dai Xiaojun Tang Department of Hepatobiliary Surgery the Second Affiliated Hospital of Southeast University Department of Medical Imaging the Second Affiliated Hospital of Southeast University

Objective：To compare radiofrequency ablation （RFA） or microwave ablation （MWA） and transcatheter arterial chemoembolization （TACE） with RFA or MWA monotherapy in hepatocellular carcinoma （HCC）.Methods：A prospective,randomized,controlled trial was conducted on 94 patients with HCC ≤7 cm at a single tertiary referral center from June 2008 to June 2010 at the Department of Hepatobiliary Surgery,the Second Affiliated Hospital of Southeast *** patients were randomly assigned into the TACERFA or TACE-MWA （combined treatment group） and the RFA-alone or MWA-alone groups （control group）.The primary end point was overall *** secondary end point was recurrence-free survival,and the tertiary end point was adverse ***：Until the time of censor,17 patients in the TACE-RFA or TACE-MWA group had *** median follow-up time of the patients who were still alive for the TACE-RFA or TACE-MWA group was 47.5±11.3 months （range,29 to 62 months）.The 1-,3-and 5-year overall survival for the TACE-RFA or TACE-MWA group was 93.6％,68.1％ and 61.7％,***-five patients in the RFA or MWA group had *** median follow-up time of the patients who were still alive for the RFA or MWA group was 47.0±12.9 months （range,28 to 62 months）.The 1-,3-and 5-year overall survival for the RFA or MWA group was 85.1％,59.6％ and 44.7％,*** patients in the TACE-RFA or TACE-MWA group had better overall survival than the RFA or MWA group [hazard ratio （HR）,0.526; 95％ confidence interval （95％ CO,0.334-0.823; P=0.002],and showed better recurrence-free survival than the RFA or MWA group （HR,0.582; 95％ CI,0.368-0.895; P=0.008）.Conclusions：RFA or MWA combined with TACE in the treatment of HCC ≤7 cm was superior to RFA or MWA alone in improving survival by reducing arterial and portal blood flow due to TACE with iodized oil before RFA.

关键词： Radiofrequency ablation (RFA) transcatheter arterial chemoembolization (TACE) hepatocellular carcinoma (HCC)

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 study on sustainable development capacity of China's coastal areas using indices dimension reduction method

引用

Journal of Geographical Sciences 2000年第4期10卷 28-36页

作者： wang Li-ming, yanG yan-feng, MAO Han-ying, CHEN Wei-min (Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China) 中科院地理科学与资源所北京

Sustainable Development Capacity (SDC) is a comprehensive concept. In order to obtain a relatively objective evaluation of it, many indices of various aspects are often used in assessing index systems. However, the overlapping information of indices is a frequent source deviating the result from the truth. In this paper, 48 indices are selected as original variables in assessing SDC of China's coastal areas. The mathematical method of dimension reducing treatment is used for eliminating the overlapping information in 48 variables. Five new comprehensive indices are extracted bearing efficient messages of original indices. On the base of new indices values, the sequencing of 12 coastal areas SDC is gained, and five patterns of sustainable development regions are sorted. Then, the leading factors and their relations of SDC in these patterns are analyzed. The gains of research are discussed in the end.

关键词： sustainable development capacity dimension reduction China's coastal areas

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

Activity of fibroblast-like synoviocytes in rheumatoid arthritis was impaired by dickkopf-1 targeting siRNA

引用

Chinese Medical Journal 2020年第6期133卷 679-686页

作者： yan-ying Liu Shi-Yao wang ying-Ni Li Wen-Jie Bian Lin-Qi Zhang Yu-Hui Li Li Long Xia Liu Xue-Wu Zhang Zhan-Guo Li Department of Rheumatology and Immunology and Beijing Key Laboratory for Rheumatism and Immune Diagnosis(BZ0135) Peking University People's HospitalBeijing 100044China Center of Clinical Immunology Peking UniversityBeijing 100044China

Background:Fibroblast-like synoviocytes(FLSs),resident mesenchymal cells of synovial joints,play an important role in the pathogenesis of rheumatoid arthritis(RA).Dickkopf-1(DKK-1)has been proposed to be a master regulator of bone remodeling in inflammatory ***,potential impairation on the activity of FLSs derived from RA to small interfering RNAs(siRNAs)targeting DKK-1 was ***:siRNAs targeting DKK-1 were transfected into FLSs of patients with ***(IL)-1β,IL-6,IL-8,matrix metalloproteinase(MMP)2,MMP3,MMP9,transforming growth factor(TGF)-pi,TGF-β2 and monocyte chemoattractant protein(MCP)-1 levels in the cell culture supernatant were detected by enzyme-linked immunosorbent assay(ELISA).Invasion assay and 3H incorporation assay were utilized to investigate the effects of siRNAs targeting DKK-1 on FLSs invasion and cell proliferation,*** blotting was performed to analyze the expression of nuclear factor(NF)-kB,interleukin-1 receptor-associared kinase(IRAK)1,extracellular regulated protein kinases(ERK)1,Jun N-terminal kinase(JNK)and p-catenin in ***:DKK-1 targeting siRNAs inhibited the expression of DKK-1 in FLSs(P<0.01).siRNAs induced a significant reduction of the levels of IL-6,IL-8,MMP2,MMP3 and MMP9 in FLSs compared to the control group(P<0.05).DKK-1 targeting siRNAs inhibited the proliferation and invasion of FLSs(P<0.05).Important molecules of pro-inflammatory signaling in FLSs,including IRAKI and ERK1,were decreased by the inhibition of DKK-1 in *** contrast,β-catenin,a pivotal downstream molecule of the Wnt signaling pathway was ***:By inhibiting DKK-1,we were able to inhibit the proliferation,invasion and pro-inflammatory cytokine secretion of FLSs derived from RA,which was mediated by the ERK or the IRAK-1 signaling *** data indicate the application of DKK-1 silencing could be a potential therapeutic approach to RA.

关键词： Dickkopf-1 Fibroblast-like synoviocytes Rheumatoid arthritis small interfering RNAs

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

一种I^2C总线接口的串行时钟芯片

引用

华中科技大学学报（自然科学版） 2006年第5期34卷 62-64页

作者：应建华陈艳郭艳华中科技大学电子科学与技术系湖北武汉430074

论述了一种采用I2C总线接口的串行实时时钟芯片的设计方法.该芯片是一个低功耗、完全BCD码的时钟/日历芯片,地址和数据通过I2C双向数据总线串行传输.时钟/日历提供秒、分、时、日、星期、月和年的时间信息;集成的249 byte的静态随机存储... 详细信息

论述了一种采用I2C总线接口的串行实时时钟芯片的设计方法.该芯片是一个低功耗、完全BCD码的时钟/日历芯片,地址和数据通过I2C双向数据总线串行传输.时钟/日历提供秒、分、时、日、星期、月和年的时间信息;集成的249 byte的静态随机存储器(SRAM)可用于存储临时信息;内置了电源电压监控电路,可使芯片在掉电时自动转入电池供电模式,并对SRAM进行掉电保护;与微处理器连接时,只占用CPU的2条I/O口线(SDA口线和SCL口线),数据传输速率最高可达400 kHz.

关键词： I^2C总线实时时钟串行接口静态随机存储器

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

大型天线变形反射面的新拟合方法

引用

西安电子科技大学学报 2005年第6期32卷 839-843页

作者：王从思段宝岩仇原鹰西安电子科技大学机电工程学院陕西西安710071

基于反射面变形形状,提出一种新的大型天线变形反射面分块拟合方法.分析了天线结构与反射面节点位移,同时分块划分变形反射面,并采用Coons曲面拟合每个块域,利用周向三角拟合曲线与径向多项式拟合曲线来确定曲面片边界条件,从而得到全... 详细信息

基于反射面变形形状,提出一种新的大型天线变形反射面分块拟合方法.分析了天线结构与反射面节点位移,同时分块划分变形反射面,并采用Coons曲面拟合每个块域,利用周向三角拟合曲线与径向多项式拟合曲线来确定曲面片边界条件,从而得到全面、准确的反射面变形信息.对7.3m口径圆抛物面天线多工况下的电性能仿真,证明了该方法的准确性和有效性.

关键词：变形面天线分块拟合辐射方向图法方程组

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

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：