检索结果-南通市图书馆

The estimation of a critical shear stress based on a bottom tripod observation in the southwest off Jeju Island,the East China Sea

引用

Acta Oceanologica Sinica 2016年第11期35卷 105-112页

作者： ZHAO Liang xu yajun YUAN Ye College of Marine and Environmental Science Tianjin University of Science and Technology National Marine Environmental Forecasting Center State Oceanic Administration

The resuspension and deposition of sediment within a bottom boundary layer（BBL） is the main dynamic processes that control the fate of the suspended sediment in shelf *** numerical study of sediment transport patterns relies on the knowledge of some critical parameters that describe sediment erosion and deposition.A critical shear stress is estimated based on field observations at the edge of a mud area southwest off Jeju Island,the East China *** the basis of the simultaneous observation of velocity and suspended sediment concentrations within the BBL by means of acoustic instruments including an acoustic Doppler velocimeter and an acoustic Doppler current profiler,the settling velocity is estimated by turbulent oscillations of the SSC under the assumption of inertial-dissipation *** method gives a mean value of 0.91 mm/s and standard deviation of 0.20 mm/s,which is an order of magnitude larger than the value obtained by an empirical method of Soulsby and by an in situ submersible particle size *** difference is possibly due to the distinct natures of two methodologies,the inertial-dissipation method is more indicative of the BBL dynamics and is thus believed to provide reasonable in situ estimates of the settling velocity,whereas Soulsby＇s method is usually suitable for still water.A novel method for estimating the critical stresses of erosion and deposition based on statistical analyses of the temporal variability of the SSC（which is defined as a derivative of the depth-averaged SSC with respect to time） and the corresponding bottom shear stress is *** critical stresses of erosion and deposition vary between 0.11 Pa and 0.25 Pa with corresponding median values of 0.20 Pa and 0.16 Pa,respectively,which confirms that the critical stresses of erosion is somewhat higher than the critical stresses of *** method of estimating the critical shear stress by means of the settling velocity is also employed,which yields reas

关键词： suspended sediment critical shear stress settling velocity East China Sea

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

Vibration analysis of a single row angular contact ball bearing with the coupling errors including the surface roundness and waviness

引用

Science China(Technological Sciences) 2020年第6期63卷 943-952页

作者： LIU Jing PANG RuiKun xu yajun DING ShiZhao HE QuBo State Key Laboratory of Mechanical Transmission Chongqing UniversityChongqing 400044China College of Mechanical Engineering Chongqing UniversityChongqing 400044China Chongqing Materials Research Institute Co.Ltd. Chongqing 400707China

Roundness and surface waviness are main manufacturing errors on the components of single row angular contact ball bearings(ACBBs).An analytical study for vibrations of the ACBBs with coupling errors including the roundness and waviness can be useful for the vibration control of the rotating ***,most previous works only focused on the single error modelling *** this paper,an improved time dependent displacement excitation(TDDE)model is proposed to consider the coupling errors including the roundness and waviness on the inner and outer races of an *** TDDE model for the roundness and waviness is established by using a combination of several sinusoidal functions.A dynamic model in the previous study is improved to consider the influences of coupling errors including the roundness and *** Hertzian contact theory and Dowson’s method are adopted to calculate the bearing contact *** time-and frequency-domain vibrations for the experimental and simulation results are compared to show some model *** influences of roundness orders and waviness amplitudes on the vibrations of the ACBB are *** obtained results show that the coupling errors including the roundness and waviness have some influence on the time-domain impulse waveform and frequency-domain spectrum characteristics of the bearing *** differences of the vibrations between the coupling errors and sing error are from 4%to 42%.This paper can provide a useful guidance for the accurate diagnosis of surface imperfections in the ACBBs.

关键词： angular contact ball bearing(ACBB) roundness error waviness error vibration dynamic model

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

Soft-sediment Deformation Structures Related to Earthquake from the Devonian of the Eastern North Qilian *** Its Tectonic Significance

引用

Acta Geologica Sinica(English Edition) 2008年第6期82卷 1185-1193页

作者： DU Yuansheng xu yajun YANG Jianghai Key Laboratory of Biogeology and Environmental Geology of Education Ministry Wuhan 430074 Faculty of Earth Sciences China University of Geosciences Wuhan 430074

Devonian in the North Qilian orogenic belt and Hexi Corridor developed terrestrial molasse of later stage of foreland basin caused by collision between the North China plate and Qaidam microplate. The foreland basin triggered a intense earthquake, and formed seismites and earthquake-related soft-sediment deformation. The soft-sediment deformation structures of Devonian in the eastern North Qilian Mts. consist of seismo-cracks, sandstone dykes, syn-depositional faults, microfoids （micro-corrugated lamination）, fluidized veins, load casts, flame structures, pillow structures and brecciation. The seismo-cracks, syn-depositional faults and microfolds are cracks, faults and folds formed directly by oscillation of earthquake. The seismic dykes formed by sediment instilling into seismic cracks. Fluidized veins were made by instilling into the seismo-fissures of the fluidized sands. The load casts, flame structures and pillow structures were formed by sinking and instilling caused from oscillation of earthquake along the face between sandy and muddy beds. The brecciation resulted from the oscillation of earthquake and cracking of sedimentary layers. The seismites and soft-sediment deformations in Devonian triggered the earthquake related to tectonic activities during the orogeny and uplift of North Qilian Mts.

关键词： North Qilian Mts. seismites soft-sediment deformation Devonian tectonics

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

Sedimentary geochemistry and provenance of the Lower and Middle Devonian Laojunshan Formation,the North Qilian Orogenic Belt

引用

Science China Earth Sciences 2010年第3期53卷 356-367页

作者： xu yajun DU YuanSheng YANG JiangHai HUANG Hu Key Laboratory of Biogeology and Environmental Geology of China Education Ministry China University of GeosciencesWuhan 430074China State Key Laboratory of Geological Processes and Mineral Resources China University of GeosciencesWuhan 430074China

The Laojunshan Formation is a suite of molasse formed during the rapid uplift of the North Qilian Orogenic Belt (NQOB). Forty-one samples of sandstone have been collected from the Sunan and Minle sections in the western sector and the Gulang and Jingyuan sections in the eastern sector of the NQOB belt. Geochemical analyses of those samples indicated: 1) The MgO+Fe2O3T and Al2O3/SiO2 values are higher, and K2O/Na2O ratios are lower in the western sector than those in the eastern sector. 2) All of them are depleted in Nb and Ta elements. The samples from the western sector are depleted in Rb element and enriched with Sc, Co, Ni, V, and Cr elements in the Upper Crust-normalized patterns. However, those from the eastern sector are depleted in Sr without enrichments of Sc, Co, Ni, V, and Cr. 3) All of the samples display a right-inclined REE pattern af- ter Chondrite-normalized REE pattern. But LaN/YbN and Eu/Eu* ratios of the samples from the western sector are lower than those of the samples from the eastern sector. These geochemical characteristics suggest the prominent input of mafic clast with minor granitic rocks into the Sunan area, felsic clast into the Gulang and Jingyuan area, and both mafic and felsic clast into the Minle area. The angular shapes of gravels imply that these ill-sorted sediments were deposited near their sources without recy- cling. Geochemical features above also demonstrated that no major chemical weathering occurred for the western provenance, but deposits in the eastern sector resulted from low or middle degree chemical weathering. Evidences combining tectonic discriminations and comparisons with potential provenances revealed that sediments in the Sunan area were derived mainly from the North Qilian Continental arc, whereas sediments in the Minle, Gulang, and Jingyuan areas were derived not only from the North Qilian Continental arc but also from the basement of the Middle Qilian block. Integrated with the characteristics of development of

关键词： North Qilian Orogenic Belt (NQOB) Laojunshan Formation sedimentary geochemistry provenance orogeny

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 Novel Vascular Disrupting Agents Noncovalent Polymeric Nanomedicine:Significantly Increased Antitumor Therapeutic Efficiency

引用

Chinese Journal of Chemistry 2022年第12期40卷 1447-1456页

作者： Jianlin Lv yajun xu Yue Huang Haiyang Yu Zhaohui Tang Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of SciencesChangchunJilin 130022China School of Applied Chemistry and Engineering University of Science and Technology of ChinaHefeiAnhui 230026China Jilin Biomedical Polymers Engineering Laboratory 5625 Renmin StreetChangchunJilin 130022China

This work was supported by the National Natural Science Foundation of China(Nos.52025035,52103195).The comprehensive graphic content and graphic abstract were created with *** by coauthors.

关键词： Vascular disrupting agents Antitumor agents Self-assembly Cancer Nanoparticles

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

New Zircon U-Pb Age of Late Devonian Tuff in Guangxi, South China and the Significance for the Paleo-Tethys Branch Ocean

引用

Acta Geologica Sinica(English Edition) 2018年第1期92卷 402-403页

作者： HU Lisha DU Yuansheng xu yajun WANG Zhiwen WANG Chenghao Collage of Marine Geosciences Key Laboratory of Submarine Geosciences and Prospecting Technology Ocean University of China Laboratory for Marine Geology Qingdao National Laboratory for Marine Science and Technology (QNLM) State Key Laboratory of Biogeology and Environmental Geology China University of Geosciences

Objective The eastern extending range of the Paleo-Tethys Ocean in southwest China has always been focused and controversial. At the beginning of this century some scholars proposed that the Paleo-Tethys Branch Ocean may extend to the Babu-Pingxiang and Cengxi areas along the stouthwestern margin of the South China Block （Cai and Zhang, 2009）. However, the pivotal proof of Late Paleozoic ophoilite and magmatic rocks was absent or sporadical in the Guangxi Zhuang Autonomous Region, resulting in insufficient evidence to support this viewpoint. For the first time this work reported the Late Devonian tuff in the Qinzhou area in the south of the Guangxi Zhuang Autonomous Region and conducted zircon U-Pb dating on it in order to constrain the extension of the Paleo-Tethys Ocean in the South China Block.

关键词： the Paleo-Tethys Branch Ocean New Zircon U-Pb Age of Late Devonian

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

Introducing urea into tirapazamine derivatives to enhance anticancer therapy

引用

National Science Review 2024年第4期11卷 245-253页

作者： yajun xu Jianlin Lv Chaoying Kong Ya Liu Kun Wang Zhaohui Tang xuesi Chen Key Laboratory of Polymer Ecomaterials Changchun Institute of Applied ChemistryChinese Academy of Sciences School of Applied Chemistry and Engineering University of Science and Technology of China

Tirapazamine（TPZ） has been approved for multiple clinical trials relying on its excellent anticancer ***,as a typical hypoxia-activated prodrug（HAP）,TPZ did not exhibit survival advantages in Phase Ⅲ clinical trials when used in combination therapy due to the insufficient hypoxia levels in patients' *** this study,to improve the therapeutic effects of TPZ,we first introduced urea to synthesize a series of urea-containing derivatives of *** urea-containing TPZ derivatives showed increased hypoxic cytotoxicity（9.51-30.85-fold） compared with TPZ,while maintaining hypoxic ***,one of these derivatives,showed 20-fold higher cytotoxicity than TPZ while maintaining a similar hypoxic cytotoxicity *** highly efficiently deliver TPZP to the tumors and reduce its side effects on healthy tissues,we further prepared TPZP into a nanodrug with fibrin-targeting ability:***4-NPs,a vascular disrupting agent,was used to increase the fibrin level within tumors and exacerbate tumor *** being combined with CA4-NPs,FT11-TPZP-NPs can accumulate in the hypoxia-aggravated tumors and activate sufficiently to kill tumor *** a single-dose treatment,FT11-TPZP-NPs+CA4-NPs showed a high inhibition rate of 98.1% against CT26 tumor models with an initial volume of ～480 mm3and four out of six tumors were completely eliminated;it thereby exerted a significant antitumor *** study provides a new strategy for improving the therapeutic effect of TPZ and other HAPs in anticancer therapy.

关键词： tirapazamine vascular disrupting agent hypoxia-activated prodrug combretastatin A4 urea

来源：

同方期刊数据库评论

在线全文

同方期刊数据库

学校读者我要写书评

暂无评论

Identification of cancer stem cells provides novel tumor models for drug discovery

引用

Frontiers of Medicine 2012年第2期6卷 112-121页

作者： Douglas D.Fang Danyi Wen yajun xu Shanghai ChemPartner Co. Ltd.998 Halei RoadZhangjiang Hi-Tech ParkPudong New DistrictShanghai 201203China

Cancer stem cells(CSCs)have received considerable attention from the research community since they were first reported in human acute myeloid leukemia 15 years *** evidence suggests that CSCs are responsible for tumor initiation and progression,drug resistance,and metastasis in both liquid and solid *** findings lead to the development of novel compounds targeting CSC populations that is becoming increasingly important for eradicating CSCs in heterogeneous tumor masses and to cure the *** 2003,we have participated in CSC studies and encountered crucial early events in the *** article reviews the history of CSC biology,clarifies the term and its definition,and further addresses the issue of how to utilize CSCs in therapeutic target discovery and drug development based on our substantial experience.

关键词： cancer stem cell tumor model drug discovery

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

Microstructure and magnetic fabric in the Shuanghe pluton:A synkinematic granite in Eastern Dabie Mountains,China

引用

Science China Earth Sciences 2004年第10期47卷 912-919页

作者： YANG Kunguang LIU Qiang LIU Yuyan MA Changqian xu yajun YANG Kuifeng Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China Faculty of Earth Sciences China University of Geosciences Wuhan 430074 China

Strain analyses for the Shuanghe pluton show that the main strain planes suffered distinct deformation. The main strain value (XZ) is up to 1.59–2.18, and the value of Flinn index (K) ranges from 0.11 to 0.82. Anisotropy of magnetic susceptibility (AMS) measurements reveal that the orientations of the magnetic foliation and lineation gently dip SE, consistent with the macroscopic foliation of the pluton. The value of anisotropy degree (P) ranges from 1.109 to 1.639, and the shape parameter (T) from 0.079 to 0.534. These studies prove that the pluton was deformed under strong compression. Quartz c-axis textures, defined by monoclinic or triclinic asymmetry, usually developed the high maxima paralleling the b-axis, which is defined by the prismatic slip (1010) under the high temperature. These fabrics are quite different from those developed in the high-ultrahigh pressure rocks (UHP) which were captured in the pluton or country rocks. It is concluded that the Shuanghe pluton emplaced under regional compression slightly after the formation of UHP, and it is characterized by synkinematic granitic deformation.

关键词： strain analysis, anisotropy of magnetic susceptibility (AMS), quartz c-axis fabric, synkinematic granite,Dabie Mountains.

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

An Exploration of Building a Thematic Sub-database within the Framework of DDE:A New Detrital Zircon U-Pb Dating Database

引用

Acta Geologica Sinica(English Edition) 2019年第S01期93卷 37-39页

作者： LI Chao LAI Wen HU Xiumian xu yajun YANG Jianghai 无 Nanjing University Nanjing 210023JiangsuChina China University of Geosciences(Wuhan) Wuhan 430074HubeiChina the DDE Sedimentary Data Group

Within the framework of the Deep-time Digital Earth(DDE)project,thematic databases driven by scientific issues will have strong scientific *** the field of sedimentology,thematic databases based on the current unified sedimentary knowledge tree established by the Sedimentary Data Group(Fig.1),can solve specific scientific problems effectively and improve the scope and utility of the DDE platform significantly.

关键词： DDE platform thematic database sedimentary knowledge tree Sedimentary Data Group

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：