检索结果-南通市图书馆

Main controlling factor and mechanism of gas-in-place content of the Lower Cambrian shale from different sedimentary facies in the western Hubei area, South China

引用

Petroleum Science 2024年第3期21卷 1488-1507页

作者： Gang Li Xian-Ming Xiao Bo-Wei Cheng Chen-Gang Lu Yue feng dong-sheng Li School of Energy Resources China University of Geosciences(Beijing)Beijing100083China Frontiers Science Center for Deep-time Digital Earth China University of Geosciences(Beijing)Beijing100083 China

The Lower Cambrian shale gas in the western Hubei area,South China has a great resource prospect,but the gas-in-place(GIP)content in different sedimentary facies varies widely,and the relevant mechanism has been not well *** the present study,two sets of the Lower Cambrian shale samples from the Wells YD4 and YD5 in the western Hubei area,representing the deep-water shelf facies and shallowwater platform facies,respectively,were investigated on the differences of pore types,pore structure and methane adsorption capacity between them,and the main controlling factor and mechanism of their methane adsorption capacities and GIP contents were *** results show that the organic matter(OM)pores in the YD4 shale samples are dominant,while the inorganic mineral(IM)pores in the YD5 shale samples are primary,with underdeveloped OM *** pore specific surface area(SSA)and pore volume(PV)of the YD4 shale samples are mainly from micropores and mesopores,respectively,while those of the YD5 shale samples are mainly from micropores and macropores,*** methane adsorption capacity of the YD4 shale samples is significantly higher than that of the YD5 shale samples,with a maximum absolute adsorption capacity of 3.13 cm^(3)/g and 1.31 cm^(3)/g in average,*** with the shallow-water platform shale,the deep-water shelf shale has a higher TOC content,a better kerogen type and more developed OM pores,which is the main mechanism for its higher adsorption *** GIP content models based on two samples with a similar TOC content selected respectively from the Wells YD4 and YD5 further indicate that the GIP content of the deep-water shelf shale is mainly 34 m^(3)/t within a depth range of 1000—4000 m,with shale gas exploration and development potential,while the shallow-water platform shale has normally a GIP content of<1 m^(3)/t,with little shale gas *** the geological and geochemical conditions of shale gas formation a

关键词： Lower Cambrian shale Deep-water shelf facies Shallow-waterplat form facies Pore structure Methane adsorption Gas-in-place content Controlling factor

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

Recent Advances in Deciphering the Mechanisms and Biological Functions of DNA Demethylation

引用

Chinese Journal of Chemistry 2024年第6期42卷 645-651页

作者： Yang feng sheng-Jun Chen Bi-feng Yuan Key Laboratory of Aquatic Product Processing Ministry of Agriculture and Rural AffairsNational R&D Center for Aquatic Product ProcessingSouth China Sea Fisheries Research InstituteChinese Academy of Fishery SciencesGuangzhouGuangdong510300 China School of Public Health Research Center of Public HealthRenmin Hospital of Wuhan UniversityWuhan UniversityWuhanHubei430071 China

5-Methylcytosine (5mC) is a dynamic and reversible epigenetic modification in genomic DNA of higher *** has been well-established that the demethylation of 5mC occurs through the ten-eleven translocation (TET)-mediated oxidation of 5mC followed by thymine DNA glycosylase (TDG)-initiated base excision repair (BER).Recent findings also have identified an alternative pathway of DNA *** this pathway,TET enzymes directly oxidize 5mC to form 5-formylcytosine (5fC) or 5-carboxylcytosine (5caC).These modified bases can undergo direct deformylation or decarboxylation,***,DNA demethylation can also occur through the deamination of 5mC and 5hmC,resulting in the production of thymine and 5-hydroxymethyluracil (5hmU),*** DNA demethylation pathways possess critical functional implications and roles in biological *** Recent Advances article will focus on the studies of mechanisms and biological functions of DNA demethylation,shedding light on the reversible nature of the epigenetic modification of 5mC.

关键词： Epigenetics DNA DNA methylation 5-Methylcytosine Demethylation Mechanisms Biological functions C—C bond cleavage Mass spectrometry

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

Copper-coated Porous Polyimide as Ultralight and Safe Current Collectors for Advanced LIBs

引用

Chinese Journal of Polymer Science 2024年第4期42卷 521-531页

作者： Cun-sheng Liu Jun-Qi Hu Ting-Ting Mao Song-Yi Liao Ru-Ming feng Yi-dong Liu Yong-Gang Min School of Materials and Energy Guangdong University of TechnologyGuangzhou510006China College of Chemistry and Chemical Engineering Zhongkai University of Agriculture and EngineeringGuangzhou510225China Shanwei Branch of Advanced Energy Science and Technology Guangdong Laboratory Shanwei516600China

Metallic copper is widely used as current collector(CC) for graphite anode of lithium-ion batteries(LIBs) due to its high electrical conductivity and electrochemical stability. However, the large volume density of commercial copper foil(~8.9 g·cm^(-3)) limits the increase of energy density of battery. Here, copper-coated porous polyimide(Cu@PPI) was prepared by vacuum evaporation as collector for the graphite anode. The sandwich structure connects the copper metal on both sides of the collector with excellent electrical conductivity. Compared to commercial Cu foil, Cu@PPI has lighter mass(≤3.9 mg for disc of 12 mm diameter versus 9.9 mg of ~10 μm Cu foil) and lower volume density(≤3.3 g·cm^(-3)). In addition, the porous structure allows of better adhesion of reactive substances and electrochemical properties than pure Cu foils. It is estimated that the energy density of Cu@PPI should be much higher than that of Cu foil. This strategy should be applicable for other current collectors.

关键词： Copper-coated Vacuum evaporation Porous polyimide(PPI) Current collector(CC) LIBs

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

Atomic-Scale Insights into Damage Mechanisms of GGr15 Bearing Steel Under Cyclic Shear Fatigue

引用

Acta Metallurgica Sinica(English Letters) 2024年第7期37卷 1265-1278页

作者： Qiao-sheng Xia dong-Peng Hua Qing Zhou Ye-Ran Shi Xiang-Tao Deng Kai-Ju Lu Hai-feng Wang Xiu-Bing Liang Zhao-dong Wang State Key Laboratory of Solidification Processing Center of Advanced Lubrication and Seal MaterialsNorthwestern Polytechnical UniversityXi’an710072China State Key Laboratory of Rolling and Automation Northeastern UniversityShenyang110819China Defense Innovation Institute Academy of Military ScienceBeijing100071China

Alternating shear stress is a critical factor in the accumulation of damage during rolling contact fatigue,severely limiting the service life of ***,the specific mechanisms responsible for the cyclic shear fatigue damage in bearing steel have not been fully *** the mechanical response and microstructural evolution of a model GGr15 bearing steel under cyclic shear loading are investigated through the implementation of molecular dynamics *** samples undergo 30 cycles under three different loading conditions with strains of 6.2%,9.2%,and 12.2%,*** findings indicate that severe cyclic shear deformation results in early cyclic softening and significant accumulation of plastic damage in the bearing ***,samples subjected to higher strain-controlled loading exhibit higher plastic strain energy and shorter fatigue ***,strain localization is identified as the predominant damage mechanism in cyclic shear fatigue of the bearing steel,which accumulates and ultimately results in fatigue ***,simulation results also revealed the microstructural reasons for the strain localization(e.g.,BCC phase transformation into FCC and HCP phase),which well explained the formation of white etching *** study provides fresh atomic-scale insights into the mechanisms of cyclic shear fatigue damage in bearing steels.

关键词： Cyclic shear fatigue Molecular dynamic simulation Bearing steels Plastic damage accumulation

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

Effects of cadium, zinc and lead on soil enzyme activities

引用

Journal of Environmental Sciences 2006年第6期18卷 1135-1141页

作者： YANG Zhi-xin LIU Shu-qing ZHENG Da-wei feng sheng-dong College of Resource and Environment China Agricultural University Beijing 100094 China College of Resource and Environment Agricultural University of Hebei Baoding 071001 China

Heavy metal （HM） is a major hazard to the soil-plant system. This study investigated the combined effects of cadium （Cd）, zinc （Zn） and lead （Pb） on activities of four enzymes in soil, including calatase, urease, invertase and alkalin phosphatase. HM content in tops of canola and four enzymes activities in soil were analyzed at two months after the metal additions to the soil. Pb was not significantly inhibitory than the other heavy metals for the four enzyme activities and was shown to have a protective role on calatase activity in the combined presence of Cd, Zn and Pb; whereas Cd significantly inhibited the four enzyme activities, and Zn only inhibited urease and calatase activities. The inhibiting effect of Cd and Zn on urease and calatase activities can be intensified significantly by the additions of Zn and Cd. There was a negative synergistic inhibitory effect of Cd and Zn on the two enzymes in the presence of Cd, Zn and Pb. The urease activity was inhibited more by the HM combinations than by the metals alone and reduced approximately 20%--40% of urease activity. The intertase and alkaline phosphatase activities significantly decreased only with the increase of Cd concentration in the soil. It was shown that urease was much more sensitive to HM than the other enzymes. There was a obvious negative correlation between the ionic impulsion of HM in soil, the ionic impulsion of HM in canola plants tops and urease activity. It is concluded that the soil urease activity may be a sensitive tool for assessing additive toxic combination effect on soil biochemical parameters.

关键词： multiple heavy metal pollution canola plants soil enzyme ionic impulsion

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

Surface engineering of Li-and Mn-rich layered oxides for superior Li-ion battery

引用

Tungsten 2024年第1期6卷 259-268页

作者： Lu-Xiang Ma Tian-dong Chen Chun-Xi Hai sheng-De dong Xin He Qi Xu Hang feng AXin Ji-Tao Chen Yuan Zhou College of Materials and Chemistry and Chemical Engineering Chengdu University of TechnologyChendu 610000China Qinghai Building and Materials Research Co. LtdXining 810000China Beijing National Laboratory for Molecular Sciences College of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

The Li-and Mn-rich layered oxides(R-LNCM)are considered as promising cathode materials for high-energy density lithium-ion batteries(LIBs).However,the interface side reaction aggravates the voltage and capacity fading between cathode material and electrolyte at high voltage,which severely hinders the practical application of LIB ***,lithium polyacrylate(LiPAA)as the binder and coating agent is applied to suppress the voltage and capacity fading of R-LNCM *** flexible LiPAA layers with high elasticity are capable of impeding cathode cracks on the particle surface via mechanical stress ***,superior voltage and capacity fading suppression on R-LNCM electrode is finally *** a result,LiPAA-R-LNCM cathode exhibits a remarkable specific capacity of 186 mA·h·g^(-1)with~73%retention at 1℃after ***,the corresponding average discharge potential is maintained to~3.1 V with only~0.4 V falling.

关键词： LiPAA interphase layer Interface side reaction Cathode cracks Capacity and voltage fading suppression Liand Mn-rich cathode

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 Deep Model for Partial Multi-label Image Classification with Curriculum-based Disambiguation

引用

Machine Intelligence Research 2024年第4期21卷 801-814页

作者： feng Sun Ming-Kun Xie sheng-Jun Huang MIIT Key Laboratory of Pattern Analysis and Machine Intelligence College of Computer Science and TechnologyNanjing University of AeronauticsandAstronauticsNanjing211106China

In this paper,we study the partial multi-label(PML)image classification problem,where each image is annotated with a candidate label set consisting of multiple relevant labels and other noisy *** PML methods typically design a disambiguation strategy to filter out noisy labels by utilizing prior knowledge with extra assumptions,which unfortunately is unavailable in many real ***,because the objective function for disambiguation is usually elaborately designed on the whole training set,it can hardly be optimized in a deep model with stochastic gradient descent(SGD)on *** this paper,for the first time,we propose a deep model for PML to enhance the representation and discrimination *** the one hand,we propose a novel curriculum-based disambiguation strategy to progressively identify ground-truth labels by incorporating the varied difficulties of different *** the other hand,consistency regularization is introduced for model training to balance fitting identified easy labels and exploiting potential relevant *** experimental results on the commonly used benchmark datasets show that the proposed method significantlyoutperforms the SOTA methods.

关键词： Partial multi-label image classification curriculum-based disambiguation consistency regularization label difficulty candidatelabel set.

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

Compositionally graded high-voltage P2-type cathode with superior structural stability and redox kinetics for advanced Na-ion batteries

引用

Nano Research 2024年第4期17卷 2755-2762页

作者： Peiyu Hou Mohan dong Zhenbo Sun feng Li School of Physics and Technology University of JinanJinan 250022China

Layered P2-type cathodes with high voltage,large capacity,and easy synthesis show great potential for developing sodium(Na)-ion batteries(NIBs).However,the P2–O2 phase transition makes their structural degradation and the Na^(+)/vacancy ordering lowers their redox ***,we rationally propose a compositionally graded P2-type cathode,where nickel(Ni)and manganese(Mn)fractions decrease gradually,and cobalt(Co)content increases contiguously from the inside to the outside of a secondary *** these particles,the Ni/Mn-based compound delivers high capacity and high *** the surface of particles,the Co/Mn-based solid solution offers a stable buffer *** from these synergistic effects,this graded P2-type cathode shows the elimination of P2–O2 transformation even when charged to 4.4 V,which enables good structural stability,maintaining capacity retention reaching~80%within 300 ***,the Na^(+)/vacancy ordering superstructure is further suppressed,and the Na^(+)diffusion kinetics is significantly *** proposed graded structure with optimized chemical composition offers a new perspective for eliminating the unwanted phase transition and thus enhancing the electrochemistry of high-voltage layered cathodes for advanced NIBs.

关键词： Na-ion battery P2-type cathode composition regulation phase transition redox stability

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

Development characteristics and controlling factors of fractures in lacustrine shale and their geological significance for evaluating shale oil sweet spots in the third member of the Shahejie Formation in the Qikou Sag, Bohai Bay Basin

引用

Petroleum Science 2024年第2期21卷 791-805页

作者： Xu Zeng Tao Yang Jian-Wei feng Cong-sheng Bian Ming Guan Wei Liu Bing-Cheng Guo Jin dong Research Institute of Petroleum Exploration and Development China National Petroleum CorporationBeijing100083China College of Geosciences China University of Petroleum(Beijing)Beijing102249China Key Laboratory of Petroleum Resources and Prospecting China University of Petroleum(Beijing)Beijing102249China School of Earth Sciences China University of PetroleumQingdao266400ShandongChina

Natural fractures are critical for shale oil and gas enrichment and development. Due to the extremely high heterogeneity of shale, the factors controlling the formation of internal fractures, especially horizontal fractures, remain controversial. In this study, we integrate thin section analysis and microcomputed tomography(CT) data from several lacustrine shale samples from the third member(Es3) of the Shahejie Formation, Qikou Sag, Bohai Bay Basin, to assess the fractures in detail. The goal is to reveal the development characteristics, controlling factors, and geological significance for evaluating sweet spots in a shale oil play. The fractures in the Es3contain high-angle structural and horizontal bed-parallel fractures that are mostly shear and extensional. Various factors influence fracture development,including lithofacies, mineral composition, organic matter content, and the number of laminae. Structural fractures occur predominantly in siltstone, whereas bed-parallel fractures are abundant in laminated shale and layered mudstone. A higher quartz content results in higher shale brittleness, causing fractures, whereas the transformation between clay minerals contributes to the development of bedparallel fractures. Excess pore pressure due to hydrocarbon generation and expulsion during thermal advance can cause the formation of bed-parallel fractures. The density of the bed-parallel and structural fractures increases with the lamina density, and the bed-parallel fractures are more sensitive to the number of laminae. The fractures are critical storage spaces and flow conduits and are indicative of sweet spots. The laminated shale in the Es3with a high organic matter content contains natural fractures and is an organic-rich, liquid-rich, self-sourced shale play. Conversely, the siltstone, massive mudstone, and argillaceous carbonate lithofacies contain lower amounts of organic matter and do not have bed-parallel fractures. However, good reservoirs can form in th

关键词： Fractures Development characteristics Controlling factors Shale oil Sweet spot

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

Applying dynamic light scattering to investigate the self-assembly process of DNA nanostructures

引用

Chinese Chemical Letters 2024年第3期35卷 316-320页

作者： Wei Yuan Gui-Zhi dong Hui Ning Xiang-Xiang Guan Jia-feng Cheng Zi-Wei Shi Xiu-Ji Du Si-Wen Meng dong-sheng Liu Yuan-Chen dong CAS Key Laboratory of Colloid Interface and Chemical ThermodynamicsInstitute of ChemistryChinese Academy of SciencesBeijing 100190China University of Chinese Academy of Sciences Beijing 100049China Dandong Bettersize Instruments Ltd. Dandong 118000China Key Laboratory of Organic Optoelectronics&Molecular Engineering of the Ministry of Education Department of ChemistryTsinghua UniversityBeijing 100084China Department of Chemistry Renmin University of ChinaBeijing 100872China

Understanding the dynamic assembly process of DNA nanostructures is important for developing novel strategy to design and construct functional *** this work,temperature-controlled dynamic light scattering(DLS)strategy has been applied to study the global assembly process of DNA origami and DNA *** the temperature dependent size and intensity profiles,the self-assembly process of various DNA nanostructures with different morphologies have been well-studied and the temperature transition ranges could be *** advantage of the DLS information,rapid preparation of the DNA origami and the brick assembly has been realized through a constant temperature *** results demonstrate that the DLS-based strategy provides a convenient and robust tool to study the dynamic process of forming hieratical DNA structures,which will benefit understanding the mechanism of self-assembly of DNA nanostructures.

关键词： Dynamic light scattering Self-assembly process DNA nanostructures Temperature transition ranges Rapid preparation

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：