期刊文献+
共找到38,630篇文章
< 1 2 250 >
每页显示 20 50 100
Insights into the Origins of Solar-Assisted Electrochemical Water Oxidation in Allotropic Co_(5.47)N/CON Heterojunctions
1
作者 Sirui Liu Qiong Gao +8 位作者 Bo Geng Lili Wu Zhikun Xu Xinzhi Ma Shijie Liu Boquan Li Mingyi Zhang Lirong Zhang Xitian Zhang 《Energy & Environmental Materials》 SCIE EI CAS CSCD 2024年第5期234-243,共10页
Solar irradiation can efficiently promote the kinetics of the oxygen evolution reaction(OER)during water splitting,where heterojunction catalysts exhibit excellent photoresponsive properties.However,insights into the ... Solar irradiation can efficiently promote the kinetics of the oxygen evolution reaction(OER)during water splitting,where heterojunction catalysts exhibit excellent photoresponsive properties.However,insights into the origins of photoassisted OER catalysis remain unclear,especially the interfaced promotion under convergent solar irradiation(CSI).Herein,novel allotropic Co_(5.47)N/CoN heterojunctions were synthesized,and corresponding OER mechanisms under CSI were comprehensively uncovered from physical and chemical aspects using the in situ Raman technique and electrochemical cyclic voltammetry method.Our results provide a unique mechanism where high-energy UV light promotes the Co^(3+/4+)conversion process in addition to the ordinary photoelectric effect excitation of the Co^(2+)material.Importantly,visible light under CSI can produce a photothermal effect for Co^(2+)excitation and Co^(3+/4+)conversion,which promotes the OER significantly more than the usual photoelectric effect.As a result,Co_(5.47)N/CoN(containing 28%CoN)obtained 317.9%OER enhancement,which provides a pathway for constructing excellent OER catalysts. 展开更多
关键词 chemical origins in situ Raman OER photothermal effect physical origins
下载PDF
Analysis on the Way of Integrating Educational Drama into Patriotism Education for Primary School Students
2
作者 Cheng CHENG 《Asian Agricultural Research》 2024年第8期42-46,共5页
In the process of patriotism education for primary school students,educational drama can play a very important role.However,the premise is that educational drama should be successfully integrated into the process of p... In the process of patriotism education for primary school students,educational drama can play a very important role.However,the premise is that educational drama should be successfully integrated into the process of patriotism education of primary school students,instead of simply and mechanically stuffing educational drama into patriotism education of primary school students.As far as the integration mode of educational drama is concerned,educational drama can be divided into three kinds,namely,discipline-oriented drama education,infiltration-oriented drama education and activity-oriented drama.Therefore,the integration methods are also divided into three categories,namely,setting up educational drama courses,using educational drama to infiltrate patriotic education into other disciplines and carrying out activity-oriented drama education. 展开更多
关键词 EDUCATIonAL DRAMA PATRIOTISM education for primary school STUDENTS way
下载PDF
Origin of the Dashuigou independent tellurium deposit at Qinghai–Xizang Plateau: constraints from the light stable isotopes C, O, and H
3
作者 Jianzhao Yin Yuhong Chao +2 位作者 Haoyu Yin Hongyun Shi Shoupu Xiang 《Acta Geochimica》 EI CAS CSCD 2024年第2期385-398,共14页
By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)... By studying the light isotopic compositions of carbon,oxygen,and hydrogen,combined with previous research results on the ore-forming source of the deposit,the authors try to uncover its metallogenic origin.The δ^(18)O and δ^(13)C isotope signatures of dolomite samples vary between 10.2 and 13.0‰,and between−7.2 and−5.2‰,respectively,implying that the carbon derives from the upper mantle.δD and δ^(18) O of quartz,biotite,and muscovite from diff erent ore veins of the deposit vary between−82 and−59‰,and between 11.6 and 12.4‰,respectively,implying that the metallogenic solutions are mainly magmatic.According to the relevant research results of many isotope geologists,the fractionation degree of hydrogen isotopes increases as the depth to the Earth’s core increases,and the more diff erentiated the hydrogen isotopes are,the lower their values will be.In other words,mantle-derived solutions can have extremely low hydrogen isotope values.This means that the δD‰ value−134 of the pyrrhotite sample numbered SD-34 in this article may indicate mantle-derived oreforming fl uid of the deposit.The formation of the Dashuigou tellurium deposit occurred between 91.71 and 80.19 Ma. 展开更多
关键词 Carbon oxygen and hydrogen isotopes origin Independent tellurium deposit the Qinghai–Xizang Plateau
下载PDF
Unroofing Technique for Anomalous Origin of the Left Coronary Artery from the Right Sinus of Valsalva: Report of a Case
4
作者 Keisuke Morimoto Futoshi Kobayashi +2 位作者 Hiromu Horie Yuki Sakaguchi Einosuke Mizuta 《World Journal of Cardiovascular Surgery》 2024年第6期69-77,共9页
Anomalous origin of the left coronary artery (AOLCA) from the right sinus of Valsalva constitutes a rare congenital coronary artery anomaly. Patients with an anomalous left main coronary artery face a significantly hi... Anomalous origin of the left coronary artery (AOLCA) from the right sinus of Valsalva constitutes a rare congenital coronary artery anomaly. Patients with an anomalous left main coronary artery face a significantly higher risk of sudden cardiac death compared to those with an anomalous right coronary artery. The anomalous coronary artery traversing between the ascending aorta and the pulmonary artery markedly heightens the risk of myocardial ischemia, arrhythmia, and sudden death. Symptomatic patients often exhibit a longer intramural course of the coronary artery, which may necessitate earlier intervention or influence the choice of surgical repair method. Surgical intervention is advocated for patients with this anomaly, even in the absence of symptoms. For anomalous aortic origin of a coronary artery from the opposite sinus of Valsalva with an intramural course, coronary unroofing is the preferred revascularization procedure. This report presents a case of AOLCA originating from the right sinus of Valsalva, treated surgically using the unroofing technique for the aortic intramural segment of the anomalous coronary artery traversing between the great vessels. The unroofing technique is recommended for treating AOLCA with an extensive intramural course that does not involve the commissure. 展开更多
关键词 Unroofing Technique Anomaly of Coronary Artery Anomalous origin of Left Coronary Artery
下载PDF
Gibbon vocal communication provides insights into the origin and evolution of human music and language
5
作者 Zi-Di Wang Hai-Gang Ma Peng-Fei Fan 《Zoological Research(Diversity and Conservation)》 2024年第2期130-132,共3页
Humans across cultures convey feelings and thoughts through music.Despite its ubiquity,the origins and evolution of music remain enigmatic.Archaeological evidence has traced the history of music back at least 40000 ye... Humans across cultures convey feelings and thoughts through music.Despite its ubiquity,the origins and evolution of music remain enigmatic.Archaeological evidence has traced the history of music back at least 40000 years ago based on prehistoric bone flutes(Fitch,2006).Comparative studies have also explored earlier histories by identifying common musical features between animals and humans(Fitch,2006).For example,songbirds exhibit categorical rhythms similar to human music(Roeske et al.,2020),and humans can recognize emotional arousal in signals across all classes of terrestrial vertebrates(Filippi et al.,2017).These findings,while surprising,align with the longstanding human perception of animal signals as music(Gray et al.,2001).The universality of music and its features intensifies the fundamental question posed by Darwin(1871):how has a behavior that is energetically costly and seemingly non-adaptive evolved to become so widespread?This question can be further divided into two sub-questions(Savage et al.,2021):(1)how do musical features contribute to the production or expressive power of music(i.e.,mechanisms),and(2)how does music benefit performers in terms of survival,reproductions,or other aspects(i.e.,functions). 展开更多
关键词 COMMUNICATIon origin evolution
下载PDF
Scientists Clarify the Origins of Lunar Metallic Iron
6
《Bulletin of the Chinese Academy of Sciences》 2024年第2期97-98,共2页
Metallic iron nanoparticles(npFe0)are widespread on the Moon,and their accumulation changes the optical spectra of the lunar surface over time.How the surface color changes largely depends on the size of npFe0:smaller... Metallic iron nanoparticles(npFe0)are widespread on the Moon,and their accumulation changes the optical spectra of the lunar surface over time.How the surface color changes largely depends on the size of npFe0:smaller npFe0 reddens the reflectance spectra,while larger npFe0 causes darkening.The resultant color variations greatly complicate remote sensing studies,posing long-term puzzles to astronomers. 展开更多
关键词 origin SURFACE reflectance
下载PDF
Origins and pathways of the subsurface and intermediate water masses of the Indonesian Throughflow derived from historical and Argo data 被引量:4
7
作者 ZHANG Yanhui YU Xiaolin WANG Fan 《Acta Oceanologica Sinica》 SCIE CAS CSCD 2008年第4期17-25,共9页
On the basis of Argo data and historic temperature/salinity data from the World Ocean Database 2001 ( WOD01 ), origins and spreading pathways of the subsurface and intermediate water masses in the Indonesian Through... On the basis of Argo data and historic temperature/salinity data from the World Ocean Database 2001 ( WOD01 ), origins and spreading pathways of the subsurface and intermediate water masses in the Indonesian Throughflow (ITF) region were discussed by analyzing distributions of salinity on representative isopyenal layers. Results were shown that, subsurface water mostly comes from the North Pacific Ocean while the intermediate water originates from both the North and South Pacific Ocean, even possibly from the Indian Ocean. Spreading through the Sulawesi Sea, the Makassar Strait, and file Flores Sea, the North Pacific subsurface water and the North Pacific Intermediate water dominate the western part of the Indonesian Archipelago. Furthermore as the depth increases, the features of the North Pacific sourced water masses become more obvious. In the eastern part of the waters, high sa- linity South Pacific subsurface water is blocked by a strong salinity front between Halmahera and New Guinea. Intermediate water in the eastern interior region owns salinity higher than the North Pacific intermediate water and the antarctic intermediate water ( AAIW), possibly coming from the vertical mixing between subsurface water and the AAIW from the Pacific Ocean, and possibly coming from the northward extending of the AAIW from the Indian Ocean as well. 展开更多
关键词 Indonesian Throughflow subsurface water intermediate water origin PATHway
下载PDF
Analysis on the Origin and Phylogenetic Status of Tong Sheep Using 12 Blood Protein and Nonprotein Markers
8
作者 孙伟 常洪 +5 位作者 杨章平 耿荣庆 角田健司 任战军 陈宏宇 Musa H.Hussein 《Journal of Genetics and Genomics》 SCIE CAS CSCD 北大核心 2007年第12期1097-1105,共9页
This study is based on the Tong sheep obtained by the random sampling method of typical colonies in the central area of Baishui County in Shaanxi Province, China. An investigation was undertaken to clarify the gene co... This study is based on the Tong sheep obtained by the random sampling method of typical colonies in the central area of Baishui County in Shaanxi Province, China. An investigation was undertaken to clarify the gene constitution of blood protein and nonprotein types of Tong sheep. Twelve genetic markers were examined by starch-gel electrophoresis and cellulose acetate electrophoresis. Polymorphism in Tong sheep was found at the following 10 loci, transferrin (Tf), alkaline phosphatase (Alp), leucine aminopeptidase (Lap), arylesterase (Ary-Es), hemoglobin-β (Hb-β), X-protein (X-p), carbonic anhydrase (CA), catalase (Cat), malate dehydrogenase (MDH), and lysine (Ly), whereas, albumin (A1) and postalbumin (Po) loci were monomorphic. Genetic approach degree method and phylogenetic relationship clustering method were used to judge the origin and phylogenetic status of Tong sheep. Results from both methods maintained that Tong sheep belonged to the "Mongolia group", and Mongolia sheep was the origin of Tong sheep. This was also supported by the history of Tong sheep breeding. Compared to the phylogenetic relationship clustering method, the genetic approach degree method was more reliable for the extraction from East and South of Central Asia, and was more effective in reflecting the breeding course of Tong sheep. 展开更多
关键词 Tong sheep origin phylogenetic status genetic approach degree phylogenetic relationship clustering
下载PDF
Interpretation of the Standards of Basic Dataset of Chronic Diseases Behavior Risk Factor Surveillance in Adults
9
作者 ZHAO Yan Fang ZHANG Mei +3 位作者 WEI Wen Qiang SUN Ke Xin LI Xin Hua WANG Li Min 《Biomedical and Environmental Sciences》 SCIE CAS CSCD 2024年第5期551-556,共6页
BACKGROUND China’s Behavioral Risk Factor Surveillance System(BRFSS)originated from the World Bankfunded HealthⅦLoan Project in the 1990s,which conducted behavioral risk factor surveillance in seven cities and one p... BACKGROUND China’s Behavioral Risk Factor Surveillance System(BRFSS)originated from the World Bankfunded HealthⅦLoan Project in the 1990s,which conducted behavioral risk factor surveillance in seven cities and one province^([1]).Drawing on the World Health Organization’s(WHO)STEPwise approach to surveillance(STEPs)and the U.S.Behavioral Risk Factor Surveillance System(BRFSS)^([2,3]). 展开更多
关键词 funded Basic originated
下载PDF
The HD-Zip transcription factor LcATHB15 is involved in litchi seed development by promoting the expression of the splicing regulator LcSR45
10
作者 Hanhan Xie Fei Wang +3 位作者 Zidi He Zhijian Liang Jianguo Li Minglei Zhao 《Horticultural Plant Journal》 SCIE CAS CSCD 2024年第6期1463-1466,共4页
Litchi (Litchi chinensis Sonn.) is a well-known tropical and subtropical woody fruit that originated from southern China (Wei et al.,2017;Hu et al.,2022).Based on the development of the embryo,litchi varieties can be ... Litchi (Litchi chinensis Sonn.) is a well-known tropical and subtropical woody fruit that originated from southern China (Wei et al.,2017;Hu et al.,2022).Based on the development of the embryo,litchi varieties can be divided into three distinct groups:large-seeded cultivars,small (abortive)-seeded cultivars and partial abortive-seeded cultivars.Seedless or the reduction in seed size due to embryo abortion is a desirable trait in fruit trees as it directly influences the texture and economic value of fleshy fruits,making small (abortive)-seeded litchi cultivars the most preferred.However,in current production practices,there is no efficient method available to induce or promote high seed abortion in litchi fruit.Therefore,understanding the stenospermy mechanisms of litchi seed development is of great significance for improving agricultural practices and managing genetic resources. 展开更多
关键词 CULTIVAR originated development
下载PDF
The running pattern of longitudinal veins at wingbase of mayflies(Insecta:Ephemeroptera)
11
作者 ZHOU Chang-Fa 《环境昆虫学报》 CSCD 北大核心 2024年第6期1326-1331,共6页
The original or primitive venation of mayflies was not presented clearly upon living materials before,this mostly results from the deform of mayfly imaginal wingbase.Some nymphs of large mayflies of China,like Siphlur... The original or primitive venation of mayflies was not presented clearly upon living materials before,this mostly results from the deform of mayfly imaginal wingbase.Some nymphs of large mayflies of China,like Siphluriscus chinensis,Ephemera pictipennis and Siphlonurus davidi,however,show some clues.Together,they demonstrate that in mayflies,subcostal brace maybe originated from longitudinal vein Anterior Subcostal(ScA),stems of Radius(R)and Media(M)are always fused at base,Media Posterior(MP)leave them first,then the branch of Rs(Radial Section)+MA(Media Anterior),Cubitus(Cu)disconnected to any other veins.Additionally,all longitudinal veins of mayflies fused with their sclerotized base respectively but without any moveable sclerite.Instead,base of R+M of mayflies sclerotized into a single one big plate,and all sclerites of wingbase are fused together rigidly by sclerotized wingbase,which disables any possible folding of mayfly wings.Phylogenetically,in the order Ephemeroptera,the different positions of ScA and Cu leaded to different and diverse venations and lineages of Ephemeroptera.In the Pterygota,the Ephemeroptera has the same fused pattern of R+M and three axillary sclerites as the Neoptera while the Odonata has the fused Cu+M,which disproves the monophyly of Paleoptera. 展开更多
关键词 VENATIon wingbase TRACHEA origin insect
下载PDF
A plausible pathway to prebiotic peptides via amino acid amides on the primordial Earth
12
作者 DingWei Gan XiangMin Lei +6 位作者 RenWu Zhou SongSen Fu Jing Sun RuSen Zhou Kostya(Ken)Ostrikov YuFen Zhao JianXi Ying 《Earth and Planetary Physics》 EI CAS CSCD 2024年第6期868-877,共10页
The prebiotic synthesis of peptides prior to ribosome-catalyzed processes remains an enigma.The synthesis of abiotic peptides from amino acids(AAs)is primarily constrained by high activation energies and unfavorable t... The prebiotic synthesis of peptides prior to ribosome-catalyzed processes remains an enigma.The synthesis of abiotic peptides from amino acids(AAs)is primarily constrained by high activation energies and unfavorable thermodynamics,necessitating the identification of plausible prebiotic alternatives for synthesizing prebiotic peptides.Here we present a plausible pathway to the formation of prebiotic peptides,wherein oligopeptides,oligopeptide amides,and cyclic oligopeptides can be directly synthesized from amino acid amides(AA-NH2)under wet–dry cycle conditions without the need for any enhancers.The subsequent investigation revealed that AA-NH2 demonstrated more favorable thermodynamic reaction effects than AAs in peptide formation.In contrast to the polymerization of AAs,the process of peptide formation through the polymerization of AA-NH2 was significantly simplified.Additionally,AA-NH2 was discovered to function as a“bridge”for the formation of peptides from AAs,thereby facilitating their participation in the synthesis of intricate peptide structures.On the basis of these findings,a plausible mechanism for the prebiotic origin network of peptides under primordial Earth conditions has been proposed.Overall,this research presents a plausible pathway for the generation of prebiotic peptides and peptide libraries within prebiotic environments. 展开更多
关键词 prebiotic chemistry origin of life chemical evolution PEPTIDE
下载PDF
Distribution and geochemical significance of alkylbenzenes for crude oil with different depositional environments and thermal maturities
13
作者 Bing-Kun Meng Dao-Fu Song +1 位作者 Yuan Chen Sheng-Bao Shi 《Petroleum Science》 SCIE EI CAS CSCD 2024年第2期777-790,共14页
A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dim... A total of 45 alkylbenzenes were detected and identified in crude oils with different depositional environments and thermal maturities from the Tarim Basin,Beibuwan Basin,and Songliao Basin using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry(GC×GCTOFMS).By analyzing the distribution characteristics of C0-C5alkylbenzenes,it is found that the content of some alkylbenzenes varies greatly in crude oils.Based on the distribution characteristics of 1,2,4,5-tetramethylbenzene(Te MB)and 1,2,3,4-Te MB,the ratio of 1,2,4,5-Te MB to 1,2,3,4-Te MB is proposed to indicate the organic matter origin and depositional environment of ancient sediments.Oil samples originated mainly from lower hydrobiont,algae,bacteria and source rocks deposited under reducing/anoxic conditions have low 1,2,4,5-/1,2,3,4-Te MB values(less than 0.6),while oil samples originated mainly from terrestrial higher plants and source rocks deposited under oxic/sub-oxic conditions have higher 1,2,4,5-/1,2,3,4-Te MB values(greater than 1.0).The significant difference of 1,2,4,5-/1,2,3,4-Te MB values is controlled by 1,2,4,5-Te MB content.1,2,4,5-Te MB content in oils derived from source rocks deposited in oxidized sedimentary environment(greater than 1.0 mg/g whole oil)is higher than that in oils from source rocks deposited in reduced sedimentary environment(less than 1.0 mg/g whole oil).1,2,4,5-/1,2,3,4-Te MB ratio might not or slightly be affected by evaporative fractionation,biodegradation and thermal maturity.1,2,4,5-/1,2,3,4-Te MB ratio and 1,2,4,5-Te MB content can be used as supplementary parameter for the identification of sedimentary environment and organic matter input.It should be noted that compared to the identification of organic matter sources,the 1,2,4,5-/1,2,3,4-Te MB parameter is more effective in identifying sedimentary environments. 展开更多
关键词 1 2 4 5-Tetramethylbenzene GC×GC-TofMS Organic matter origin Depositional environment
下载PDF
Genetic analyses of ancient tea trees provide insights into the breeding history and dissemination of Chinese Assam tea(Camellia sinensis var.assamica)
14
作者 Miao-Miao Li Muditha K.Meegahakumbura +5 位作者 Moses C.Wambulwa Kevin S.Burgess Michael Möller Zong-Fang Shen De-Zhu Li Lian-Ming Gao 《Plant Diversity》 SCIE CAS CSCD 2024年第2期229-237,共9页
Chinese Assam tea(Camellia sinensis var.assamica)is an important tea crop with a long history of cultivation in Yunnan,China.Despite its potential value as a genetic resource,its genetic diversity and domestication/br... Chinese Assam tea(Camellia sinensis var.assamica)is an important tea crop with a long history of cultivation in Yunnan,China.Despite its potential value as a genetic resource,its genetic diversity and domestication/breeding history remain unclear.To address this issue,we genotyped 469 ancient tea plant trees representing 26 C.sinensis var.assamica populations,plus two of its wild relatives(six and three populations of C.taliensis and C.crassicolumna,respectively)using 16 nuclear microsatellite loci.Results showed that Chinese Assam tea has a relatively high,but comparatively lower gene diversity(H_(S)=0.638)than the wild relative C.crassicolumna(H_S=0.658).Clustering in STRUCTURE indicated that Chinese Assam tea and its two wild relatives formed distinct genetic groups,with considerable interspecific introgression.The Chinese Assam tea accessions clustered into three gene pools,corresponding well with their geographic distribution.However,New Hybrids analysis indicated that 68.48%of ancient Chinese Assam tea plants from Xishuangbanna were genetic intermediates between the Puer and Lincang gene pools.In addition,10%of the ancient Chinese Assam tea individuals were found to be hybrids between Chinese Assam tea and C.taliensis.Our results suggest that Chinese Assam tea was domesticated separately in three gene pools(Puer,Lincang and Xishuangbanna)in the Mekong River valley and that the hybrids were subsequently selected during the domestication process.Although the domestication history of Chinese Assam tea in southwestern Yunnan remains complex,our results will help to identify valuable genetic resources that may be useful in future tea breeding programs. 展开更多
关键词 Tea plant Hybrid origin Genetic diversity Domestication history Camellia sinensis var.assamica Camellia taliensis
下载PDF
Gas source of the Middle Jurassic Shaximiao Formation in the Zhongjiang large gas field of Western Sichuan Depression:Constraints from geochemical characteristics of light hydrocarbons
15
作者 Xiaoqi Wu Jun Yang +4 位作者 Ping Wang Huaji Li Yingbin Chen Chunhua Ni Huasheng Zeng 《Energy Geoscience》 EI 2024年第2期141-151,共11页
The Zhongjiang gas field is a typical large gas field in terrigenous strata of the Western Sichuan Depression.It remains debatable which member of the Upper Triassic Xujiahe Formation served as the source rocks and ho... The Zhongjiang gas field is a typical large gas field in terrigenous strata of the Western Sichuan Depression.It remains debatable which member of the Upper Triassic Xujiahe Formation served as the source rocks and how significant the member contributed to the gas accumulations in the Zhongjiang gas field.In this study,we analyzed the essential characteristics of the Lower Jurassic source rocks and the geochemical features of light hydrocarbons in natural gas from the 2nd(T_(3)χ^(2))and 4th members(T_(3)χ^(4))of the Upper Triassic Xujiahe Formation(T_(3)χ),as well as the Middle Jurassic Shaximiao(J_(2)s)and Qianfoya(J_(2)q)formations.Based on this,we explored the sources of the natural gas in the Zhongjiang gas field and determined the natural gas migration patterns and their effects on the properties of light hydrocarbons in the natural gas.The results indicate that the Lower Jurassic lacustrine source rocks of the Zhongjiang gas field contain humic organic matter,with vitrinite reflectance(R_(0))values ranging from 0.86%to 0.98%.Samples meeting the criterion for effective source rocks[total organic carbon(TOC)content≥0.75%]exhibited an average TOC content of merely 1.02%,suggesting significantly lower hydrocarbon generation potential than source rocks in the underlying T3x,which show higher thermal maturity and TOC contents.For natural gas samples from T_(3)χ^(2),T_(3)χ^(4),J_(2)s,and J_(2)q reservoirs,their C_(5-7)iso-alkane content was significantly higher than their n-alkane content,and their methylcyclohexane(MCH)index ranged from 59.0%to 77.3%,indicating the predominance of methylcyclohexane in C_(7)light hydrocarbons.As indicated by the origin identification and gas-source correlation based on the geochemical features of light hydrocarbons,the natural gas in the Zhongjiang gas field is typical coal-derived gas.The gas from the primary pay zone of the Shaximiao Formation,with significantly high K_(1),(P_(2)+N_(2))/C_(7),and P_(3)/C_(7)values,predominantly originated from the 5th member of the T3x and migrated in the free phase,with a small amount possibly sourced from the Lower Jurassic source rocks.The dissolution and adsorption during gas migration led to a decrease in the aromatic content in C_(6-7)light hydrocarbons and an increase in the isoheptane values.Therefore,their effects must be considered when determining the gas origin and thermal maturity based on the aromatic content in C_(6-7) light hydrocarbons and iso-heptane values. 展开更多
关键词 Zhongjiang gas field Source rock origin of natural gas Light hydrocarbon geochemistry Natural gas migration
下载PDF
Tracing of natural gas migration by light hydrocarbons:A case study of the Dongsheng gas field in the Ordos Basin,NW China
16
作者 WU Xiaoqi NI Chunhua +3 位作者 MA Liangbang WANG Fubin JIA Huichong WANG Ping 《Petroleum Exploration and Development》 SCIE 2024年第2期307-319,共13页
Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical char... Based on the analysis of light hydrocarbon compositions of natural gas and regional comparison in combination with the chemical components and carbon isotopic compositions of methane,the indication of geochemical characteristics of light hydrocarbons on the migration features,dissolution and escape of natural gas from the Dongsheng gas field in the Ordos Basin is revealed,and the effect of migration on specific light hydrocarbon indexes is further discussed.The study indicates that,natural gas from the Lower Shihezi Formation(Pix)in the Dongsheng gas field displays higher iso-C5-7contents than n-C5-7contents,and the C6-7light hydrocarbons are composed of paraffins with extremely low aromatic contents(<0.4%),whereas the C7light hydrocarbons are dominated by methylcyclohexane,suggesting the characteristics of coal-derived gas with the influence by secondary alterations such as dissolution.The natural gas from the Dongsheng gas field has experienced free-phase migration from south to north and different degrees of dissolution after charging,and the gas in the Shiguhao area to the north of the Borjianghaizi fault has experienced apparent diffusion loss after accumulation.Long-distance migration in free phase results in the decrease of the relative contents of the methylcyclohexane in C7 light hydrocarbons and the toluene/n-heptane ratio,as well as the increase of the n-heptane/methylcyclohexane ratio and heptane values.The dissolution causes the increase of isoheptane values of the light hydrocarbons,whereas the diffusion loss of natural gas in the Shiguhao area results in the increase of n-C5-7contents compared to the iso-C5-7contents. 展开更多
关键词 Ordos Basin Dongsheng gas field Permian Lower Shihezi Formation light hydrocarbon compounds MATURITY natural gas origin migration phase state diffusion loss
下载PDF
On the Proof of the Contradiction of Set Theory
17
作者 Yury M. Volin 《Advances in Pure Mathematics》 2024年第3期139-159,共21页
The article is devoted to proving the inconsistency of set theory arising from the existence of strange trees. All steps of the proof rely on common informal set-theoretic reasoning, but they take into account the pro... The article is devoted to proving the inconsistency of set theory arising from the existence of strange trees. All steps of the proof rely on common informal set-theoretic reasoning, but they take into account the prohibitions that were introduced into axiomatic set theories in order to overcome the difficulties encountered by the naive Cantor set theory. Therefore, in fact, the article is about proving the inconsistency of existing axiomatic set theories, in particular, the ZFC theory. 展开更多
关键词 Set theory Inconsistency TREE Strange Tree Through way Almost through way ISOMORPHISM Almost Isomorphism Isomorphism Tree Place Plane Superposition of Trees on the Place Plane Disposition of Trees on the Place Plane
下载PDF
On the Relationship between the Original and the Translated Version——The Interpretation of Benjamin's Three Metaphors
18
作者 孙静 《海外英语》 2014年第20期162-163,167,共3页
This paper explores the relationship between the original and its translation by interpreting Benjamin's three metaphors from his The Translator's Task. The exploration starts with the metaphor of"the tan... This paper explores the relationship between the original and its translation by interpreting Benjamin's three metaphors from his The Translator's Task. The exploration starts with the metaphor of"the tangent of a circle",where it is interpreted that although the translated version should be faithful to its original in terms of meaning,yet it is a deviation due to different internal and external factors. Then,in the metaphor of"afterlife",the discussion demonstrates that the translated version proceeds from the original,but the original depends on it for its survival and afterlife in different eras. Later,based on the metaphor of"fragments of a vessel",the author states that the original and its translation are equal and complementary,just like the fragments of a vessel,responsible for the development and renewal of each other through translation. Finally,it is concluded that a better understanding of their relationship can offer us a new perspective in translation studies and practice. 展开更多
关键词 relationship BETWEEN the originAL and the translat
下载PDF
Completion of the Proof of the Contradiction of Set Theory
19
作者 Yury M. Volin 《Advances in Pure Mathematics》 2024年第11期807-816,共10页
The article is devoted to completing the proof of the inconsistency of set theory. In this article and in the two preceding ones, all steps of the proof are based on generally accepted informal set-theoretic reasoning... The article is devoted to completing the proof of the inconsistency of set theory. In this article and in the two preceding ones, all steps of the proof are based on generally accepted informal set-theoretic reasoning, but consider the prohibitions that were included in axiomatic set theories in order to overcome the difficulties encountered by the naive Cantor set theory. Therefore, in fact, the articles are about proving the inconsistency of existing axiomatic set theories, in particular, the ZFC theory. 展开更多
关键词 Set theory Inconsistency TREE Strange Tree Through way Almost through way ISOMORPHISM Almost Isomorphism Isomorphism Tree Place Plane Superposition (Imposition) of Trees on the Place Plane Disposition of Trees on the Place Plane
下载PDF
Characterizing the Provenance Signatures and Geochemical Behaviors of Turquoise in Copper Deposits:Comparative Case Studies of Meiduk,Iran,and Tongling,China
20
作者 Bahareh Shirdam Mingxing Yang +2 位作者 Jia Liu Ling Liu Andy Hsitien Shen 《宝石和宝石学杂志(中英文)》 CAS 2024年第S01期71-73,共3页
Turquoise, a hydrous phosphate of copper and aluminum, is highly valued for its unique colour and historical significance. The similarity in colour, quality, and pattern between turquoises from different localities ma... Turquoise, a hydrous phosphate of copper and aluminum, is highly valued for its unique colour and historical significance. The similarity in colour, quality, and pattern between turquoises from different localities may lead to confusion in determining their origins. This is particularly evident in the case of turquoises from Meiduk in Iran and Tongling in China(Fig.1).In Iran, turquoise deposits are typically associated with magmatic zones, specifically in the Meiduk mine, located 85 kilometers northwest of the Sar Cheshmeh porphyry copper deposit in Kerman Province. The deposit is hosted by Eocene volcanic rocks of andesitic-basaltic composition with porphyry-type mineralization associated with two Miocene calc-alkaline intrusive phases. Five distinct zones of the hypogene alteration include potassic, potassic-phyllic, phyllic, and propylitic zones, which are rich in magnetite. Mineralization processes include stockwork, dissemination, veinlets, and veins rich in garnet, chalcopyrite, magnetite, and anhydrite. Turquoise is found in transitional, leached, and supergene zones, primarily as fracture and seam fillers. In contrast, Chinese turquoises are more often found in sedimentary rocks, with significant exceptions in places like the Tongling mine in Anhui Province, which are hosted within magmatic rocks. The turquoise from Tongling is found in the Tongling area within the Middle-lower Yangtze Metallogenic Belt, an area characterized by complex tectonics and intense magmatic and metallogenic activities. The turquoise deposits are associated with iron-copper polymetallic mineralization within Early Cretaceous volcanic rocks.The turquoise from Meiduk exhibited a specific gravity range of 2.22 g/cm^(3)to 2.71 g/cm^(3), SWUV fluorescence from none to medium, and LWUV fluorescence from faint to strong, indicating diverse mineralogical compositions. SEM examination of turquoise from Meiduk reveals a variety of mineral morphologies. The turquoise displays closely packed arrays of elongated needle-like crystals, measuring 2 μm to 9 μm in length and 0.1 μm to 0.4 μm in thickness, indicating a dynamic growth environment. The density and alignment of these crystals suggest the space-constrained setting, likely influenced by rapid deposition from mineral-laden fluids, with crystals interlocked due to simultaneous nucleation events. Some crystals appear similarly elongated but are more dispersed, with greater separation between individual crystals. In other areas, the elongated turquoise crystals are tightly intergrown, creating a dense textural appearance, pointing to a stage where growth space became limited, resulting in an interlocking matrix. Additionally, some crystals radiate outward from a central point, forming a spherical pattern reaching about 18 μm. The turquoise from Tongling show a specific gravity range of 2.26 g/cm^(3)to 2.60 g/cm^(3), with consistent medium SWUV fluorescence and strong LWUV fluorescence. SEM examination reveals needle structures, plate-like structures, and spheroidal aggregates composed of needle and plate-like microcrystals. These spherical aggregates, some with diameters around 26 μm, exhibit the concentric growth structure covered by turquoise microcrystals, with crystal lengths of 8 μm. The surface needle-like microcrystals vary in size, approximately 3 μm in length, 2 μm in width, and 0.2 to 0.6 μm in thickness.Optical microscopy, Raman and FTIR spectroscopy reported the presence of quartz, gypsum, iron oxides such as jarosite and goethite, biotite, sericite, pyrite, galena, bornite, graphene oxide, malachite, and azurite as major associated minerals of Meiduk's. In contrast, the Tongling mine features minerals such as quartz, anatase, barite, sodium feldspar, illite, and malachite.Through EPMA and LA-ICP-MS results, the turquoises of Tongling exhibit similar average iron content(1.28% and 1.26% respectively), but significant differences in copper content. The turquoises of Meiduk have the average copper content of 6.97%, whereas Tongling samples show the higher content of 11.38%. Na, K, and Ca concentrations are also higher in Meiduk samples, suggesting interaction with alkali-rich fluids and potassic alteration. Trace elements such as Ti, Cr, Zn, Se, and Mo serve as tracing agents for Meiduk samples, while Be and W are associated with Tongling samples. Regarding rare earth elements(REEs), Meiduk samples show diverse δCe(0.14-4.62) and δEu(0.65-15.78) values, indicating a wide range of oxidation states and europium anomalies. The significant variability in LREE/HREE ratios(0.39-31.74) and ΣREE concentrations(0.25-240.72 ppm) suggests heterogeneous REE fractionation patterns. In contrast, Tongling samples display δCe(0.070-2.51) and δEu(0.238-4.87) ranges, with more consistent LREE/HREE ratios(0.128-10.2) and ΣREE values(0.069-4.08 ppm), indicating stable REE fractionation dynamics.This comparative study of turquoises from the Meiduk mine in Iran and the Tongling mine in China reveals significant similarities and differences in their geochemical and mineralogical characteristics. Both deposits are hosted within magmatic rocks and produce turquoise as a byproduct in open-pit copper mining operations, exhibiting comparable colors, patterns, and morphologies. However, distinct differences are noted in their mineral compositions and trace elements, with turquoise from Meiduk associated with a complex hydrothermal system rich in various sulfide and oxide minerals and higher copper, Na, K, and Ca concentrations, indicating alkali-rich fluid interactions. In contrast, the turquoise from Tongling, influenced by both volcanic and sedimentary processes, shows a higher copper content, presence of barite, and different trace elements such as Be and W. The REE patterns also highlight the contrasting geological histories and environmental conditions at each site, with Meiduk samples showing a broader range of oxidation states and europium anomalies compared to the more stable REE fractionation dynamics in Tongling samples. These differences underscore the importance of detailed geochemical and mineralogical analyses for accurate provenance determination in gemmological and archaeological contexts. 展开更多
关键词 TURQUOISE copper mine origin determination Meiduk Iran Tongling China
下载PDF
上一页 1 2 250 下一页 到第
使用帮助 返回顶部