期刊文献+
共找到350,687篇文章
< 1 2 250 >
每页显示 20 50 100
Thermal decomposition and kinetics of diisopropyl methylphosphonate(DIMP),a chemical warfare agent simulant
1
作者 Natalie Gese Hergen Eilers 《Defence Technology(防务技术)》 2026年第1期40-51,共12页
Chemical warfare agents(CWAs)remain a persistent hazard in many parts of the world,necessitating a deeper exploration of their chemical and physical characteristics and reactions under diverse conditions.Diisopropyl m... Chemical warfare agents(CWAs)remain a persistent hazard in many parts of the world,necessitating a deeper exploration of their chemical and physical characteristics and reactions under diverse conditions.Diisopropyl methylphosphonate(DIMP),a commonly used CWA surrogate,is widely studied to enhance our understanding of CWA behavior.The prevailing thermal decomposition model for DIMP,developed approximately 25 years ago,is based on data collected in nitrogen atmospheres at temperatures ranging from 700 K to 800 K.Despite its limitations,this model continues to serve as a foundation for research across various thermal and reactive environments,including combustion studies.Our recent experiments have extended the scope of decomposition analysis by examining DIMP in both nitrogen and zero air across a lower temperature range of 175℃ to 250℃.Infrared spectroscopy results under nitrogen align well with the established model;however,we observed that catalytic effects,stemming from decomposition byproducts and interactions with stainless steel surfaces,alter the reaction kinetics.In zero air environments,we observed a novel infrared absorption band.Spectral fitting suggests this band may represent a combination of propanal and acetone,while GCMS analysis points to vinyl formate and acetone as possible constituents.Although the precise identity of these new products remains unresolved,our findings clearly indicate that the existing decomposition model cannot be reliably extended to lower temperatures or non-nitrogen environments without further revisions. 展开更多
关键词 chemical warfare agents Simulants Diisopropyl methylphosphonate Thermal decomposition Decomposition model PROPANAL Vinyl formate ACETONE
在线阅读 下载PDF
Tree community composition modulates early-stage decomposition of standard litter through chemical and physical engineering
2
作者 Joachim López Karen Vancampenhout +1 位作者 Bart Muys Quentin Ponette 《Forest Ecosystems》 2026年第1期22-34,共13页
Litter decomposition is an essential ecosystem process influenced by multiple factors,including substrate quality,climate,edaphic environment,and decomposer communities.However,the role of canopy species identity and ... Litter decomposition is an essential ecosystem process influenced by multiple factors,including substrate quality,climate,edaphic environment,and decomposer communities.However,the role of canopy species identity and diversity on leaf litter decomposition in forests remains understudied.By controlling for macroclimate,soil properties,and litter substrate in a mature common garden,we investigated whether a three-month tea bag incubation of standardized green and rooibos tea substrate is driven by canopy tree species characteristics and diversity.Our study hypothesized two primary pathways:a chemical engineering effect,where trees alter soil properties and decomposer communities through litter input,and a physical engineering effect,where tree canopy structure modulates the local microclimate.The results showed that even under uniform macroclimatic and initial soil conditions,mass loss rates varied widely for green tea(27.4%–73.2%)and rooibos tea(6.1%–34.7%),comparable as found in other research between distinct biomes.While substrate quality was the dominant factor,both engineering pathways and,to a minor extent,tree diversity modulated mass losses.For green tea,tree chemical and physical characteristics seemed equally important,while the physical environment showed an increased importance for rooibos.Incubation depth played a key role,where forest floor decomposition rates are more susceptible to temporal climate variations,and soil-layer decomposition rates are less susceptible to climate variations and more determined by tree species identity.Our findings suggest that tea bag experiments focusing solely on topsoil burial may underestimate processes in the forest floor and the mineralorganic boundary layer.This study underscores the critical role of litter substrate quality in decomposition while demonstrating that tree community composition and the associated herbaceous layer,through both chemical and physical engineering pathways,strongly modulate decomposition rates. 展开更多
关键词 Tea bag incubation Early-stage litter decomposition Geographical arboretum Tree species composition
在线阅读 下载PDF
Chemical composition and biological activities of Angelica sinensis 被引量:2
3
作者 Jiankun Jin Zixuan Che +4 位作者 Rui Liu Ruiqi Ma Ying Li Meng Zhang Yu Chen 《Asian Journal of Traditional Medicines》 2025年第6期285-296,共12页
Angelica sinensis(A.sinensis),as a kind of Chinese medicine,has the effects of tonifying blood,promoting blood circulation,regulating menstrual flow,relieving pain,moistening bowel and so on.By consulting Sciencedirec... Angelica sinensis(A.sinensis),as a kind of Chinese medicine,has the effects of tonifying blood,promoting blood circulation,regulating menstrual flow,relieving pain,moistening bowel and so on.By consulting Sciencedirect database and Web of Science database,163 related articles were found,of which 36 were related to chemical composition and pharmacological activities of A.sinensis.In this paper,the chemical structures and different derivatives were systematically summarized by reviewing relevant literatures,and the pharmacological effects were also summarized. 展开更多
关键词 Angelica sinensis chemical composition biological activity
暂未订购
Chemical Composition, Antioxidant Property, and Nematicidal Activity of Cucumis metuliferus
4
作者 Hao ZHANG Jianguo WANG +8 位作者 Xuejun ZHANG Jihao CHEN Qigan LIANG Xiaofa FU Min WANG Bo ZHOU Qiang GAO Haibo WU Yuan HUANG 《Medicinal Plant》 2025年第2期7-13,共7页
[Objectives]To investigate the chemical composition,antioxidant property,and nematicidal activity of Cucumis metuliferus and establish a theoretical foundation for the development of botanical nematicides.[Methods]The... [Objectives]To investigate the chemical composition,antioxidant property,and nematicidal activity of Cucumis metuliferus and establish a theoretical foundation for the development of botanical nematicides.[Methods]The compounds were isolated and purified using silica gel,reversed-phase medium,low-pressure gel Sephadex LH-20 column chromatography,and preparative high-performance liquid chromatography.Their identification was based on physicochemical properties,various spectral analyses,and data reported in the literature.Subsequently,the nematicidal and antioxidant activities of the isolated compounds were evaluated.[Results]A total of four compounds were isolated from C.metuliferus,which were identified as isovitexin-2″-O-glucoside(compound 1),9E,11E-(13-oxo)tridecadienoic acid(compound 2),2E,4E-tridecadienedioic acid(compound 3),and 9E,11E-(13-hydroxy)tridecadienoic acid(compound 4).Compound 1 demonstrated a notable degree of antioxidant activity,achieving a DPPH scavenging rate of 49.40%at a mass concentration of 1 mg/mL.Additionally,compounds 1,3,and 4 exhibited varying levels of nematicidal activity.Specifically,compound 1 displayed strong nematicidal activity at a concentration of 2.0 mg/mL,resulting in a mortality rate of 90.5%against nematodes.Furthermore,compounds 3 and 4 achieved a mortality rate of 100%against nematodes at a concentration of 0.25 mg/mL.[Conclusions]This study reports the first isolation of four compounds:isovitexin-2″-O-glucoside,9E,11E-(13-oxo)tridecadienoic acid,2E,4E-tridecadienedioic acid,and 9E,11E-(13-hydroxy)tridecadienoic acid from C.metuliferus.Notably,2E,4E-tridecadienedioic acid and 9E,11E-(13-oxo)tridecadienoic acid are identified as novel natural products.Among these compounds,isovitexin-2″-O-glucoside,9E,11E-(13-oxo)tridecadienoic acid,and 9E,11E-(13-hydroxy)tridecadienoic acid exhibit nematicidal activity,whereas isovitexin-2″-O-glucoside demonstrates antioxidant properties. 展开更多
关键词 Cucumis metuliferus Botanical pesticide chemical composition Root knot nematode Antioxidant property Nematicidal activity
在线阅读 下载PDF
Chemical composition differences in wild Gardenia jasminoides fruits across provenances using metabolomics
5
作者 Wen-Yi Bi Wen-Lin He +3 位作者 Wei Wang Xin-Ruo Wang Zhi-Jun Zhou Yan-Ling Zeng 《World Journal of Biological Chemistry》 2025年第3期10-26,共17页
BACKGROUND Fruits of Gardenia jasminoides(G.jasminoides)have extremely high medicinal value.However,the quality and traits of the plants vary significantly based on their provenances.In addition,the behaviour of the k... BACKGROUND Fruits of Gardenia jasminoides(G.jasminoides)have extremely high medicinal value.However,the quality and traits of the plants vary significantly based on their provenances.In addition,the behaviour of the known bioactive components,such as geniposide and crocin,has been the primary focus of the research on G.jasminoides.However,the identification of unknown bioactive components and their metabolomics remains underexplored.Therefore,analysing the metabolic differences between gardenias from different sources is essential to provide a comprehensive theoretical basis for the evaluation of G.jasminoides and germplasm resource identification.AIM To systematically evaluate the morphology,secondary metabolites,typical active ingredients,and antioxidant activity of wild G.jasminoides fruits.METHODS Gardenia fruits were collected from different provenances.Metabolites were identified via ultra-high-performance liquid chromatography–tandem mass spectrometry(UPLC-MS/MS).The metabolic differences were compared using hierarchical cluster analysis(HCA).The antioxidant capacity was evaluated using 2,2-diphenyl-1-picrylhydrazyl radical scavenging assays and ferric reducing antioxidant power assays,and its correlation with typical active ingredients was analysed.RESULTS A total of 444 and 240 metabolites were identified using UPLC-MS/MS in positive and negative ion modes,respectively.The HCA results of the flavonoids indicated that the higher content of flavonoids was in the fruits from Lukou.The differential analysis of metabolites in fruits from Shaoyang,Miluo and Lukou showed that the fruit from Miluo had the highest upregulated differential metabolites.CONCLUSION The metabolic characteristics of the Ningxiang and Xiangxi extracts were similar,while those of Lukou,Miluo and Shaoyang extracts differed significantly. 展开更多
关键词 Gardenia jasminoides fruit Antioxida Gardenia jasminoides fruit Antioxidant activity chemical composition Metabolomics Differential substances
暂未订购
The chemical composition, quality control and pharmacological effects of Gualou-Xiebai-Banxia Decoction: a review
6
作者 Yan-Tao Wang Yin-Yan Lai +4 位作者 Li Wang Xiao-Li Zheng Hong-Ju Li Su-Hong Chen Zheng Xiang 《Traditional Medicine Research》 2025年第4期72-82,共11页
Gualou-Xiebai-Banxia Decoction(GXBD)is a traditional Chinese herbal formula including four traditional Chinese medicines:Gualou(Trichosanthis Fructus,TF),Xiebai(Allii Macrostemonis Bulbus,AMB),Banxia(Pinelliae Rhizoma... Gualou-Xiebai-Banxia Decoction(GXBD)is a traditional Chinese herbal formula including four traditional Chinese medicines:Gualou(Trichosanthis Fructus,TF),Xiebai(Allii Macrostemonis Bulbus,AMB),Banxia(Pinelliae Rhizoma,PR)and yellow wine.It is a classical therapy for chest stuffiness and pain syndrome and is widely used in the clinical treatment of coronary heart disease.It also shows significant therapeutic effects on pulmonary heart disease,hyperlipidemia,and arrhythmia.This study conducted a literature review and collected information on GXBD from databases such as PubMed,Web of Science,China National Knowledge Infrastructure,and ScienceDirect.The result indicated that the main active ingredients of GXBD are steroids,flavonoids,terpenoids,alkaloids,amino acids,and organic acids.Trigonelline,macrostemonoside and cucurbitacin B can provide reference for its quality control.GXBD may exert therapeutic effects on coronary heart disease through AMPK,PI3K-AKT,oxLDL,VEGF,and NF-κB signal pathways.This review provides a comprehensive analysis and summary of the chemical composition and in vivo metabolism of three traditional Chinese medicines(TF,AMB,and PR),along with an evaluation of the chemical composition,quality control,pharmacological effects,and clinical application of GXBD.Based on these,areas requiring further research on GXBD have been proposed to provide a reference for its further development and new drug research. 展开更多
关键词 Gualou-Xiebai-Banxia Decoction chemical composition chest stuffiness quality control pharmacological mechanism
暂未订购
Changes in the urban dew chemical composition in Northeast China from 2013 to 2023
7
作者 Yingying Xu Haodong Hou +2 位作者 Yachao Zhang Yunze Zhao Xiaoteng Liu 《Journal of Environmental Sciences》 2025年第11期633-644,共12页
The chemical composition of dew is closely related to the air quality.Since 2013,China has promulgated a series of laws and regulations focused on air pollution control,and remarkable results have been achieved over t... The chemical composition of dew is closely related to the air quality.Since 2013,China has promulgated a series of laws and regulations focused on air pollution control,and remarkable results have been achieved over the past decade.As an indicator of near-surface air quality,the chemical composition of dew obviously changes.The dew quality was affected mainly by the local air quality.The mean dew pH was 6.3±0.4(n=186)from 2013 to 2023,and the order of ions was SO_(4)^(2-)(3180.7±3592.0μeq/L)>NH_(4)^(+)(2552.3±2971.8μeq/L)>Ca^(2+)(1006.2±945.5μeq/L)>NO_(3)^(-)(397.2±511.0μeq/L)>Cl^(-)(152.3±133.4μeq/L)>K^(+)(149.4±191.6μeq/L)>F^(-)(133.0±110.3μeq/L)>Na^(+)(123.8±94.9μeq/L)>Mg^(2+)(83.3±65.6μeq/L).The dew quality deteriorated on hazy days.There were no haze events during the condensation period after 2020,which caused a significant reduction in the concentration of the main ions in the dew.Over the past decade,electrical conductivity(EC),total dissolved solids(TDS),PM_(2.5) and PM_(10),as well as major ions(SO_(4)^(2-),NO_(3)^(-),NH_(4)^(+),Ca^(2+),Cl^(-),Na^(+),F^(-),K^(+)and Mg^(2+))in dew,have all tended to decrease.The annualmean NO_(3)^(-)concentration in 2023 was 86.5%lower than that in 2013,with values of 79.3%for SO_(4)^(2-),77.3%for Ca^(2+),76.7%for NH_(4)^(+),74.6%for K^(+),65.4%for Mg^(2+),63.4%for Na^(+),61.7%for Cl^(-),and 60.3%for F^(-). 展开更多
关键词 Dew chemical composition Ionic component Air quality Emission reduction Haze event
原文传递
Advancements in Chemical Composition,Pharmacological Activities,and Extraction and Processing Techniques of Star Anise(Illicium verum)
8
作者 Danna HUANG Cong WANG +1 位作者 Qin WEI Lu CHEN 《Medicinal Plant》 2025年第6期86-95,共10页
This paper systematically categorizes the primary composition of star anise(Illicium verum),including volatile oils,flavonoids,phenolic acids,and sesquiterpene lactones,and further analyzes the pharmacological activit... This paper systematically categorizes the primary composition of star anise(Illicium verum),including volatile oils,flavonoids,phenolic acids,and sesquiterpene lactones,and further analyzes the pharmacological activities,such as antibacterial,analgesic,anti-inflammatory,and antioxidant effects.Additionally,it summarizes key aspects of extraction techniques,analytical methods,and fresh material processing technologies.The objective is to provide a robust foundation for enhancing research methods and technological standards related to star anise,thereby improving resource utilization efficiency and facilitating its industrial applications. 展开更多
关键词 Star anise(Illicium verum) chemical composition Pharmacological activity EXTRACTION Processing technique
暂未订购
Review on the research progress into the traditional Chinese medicinal Jing Fang granules:chemical composition,pharmacological effects and clinical applications
9
作者 Rui Zhao Tai-Li Zhao +6 位作者 Hong-Hua Li Pei-Pei Zhao Meng-Meng Wang Yi-Wei Meng Jing-Li Ren Xin Yin Jing-Chun Yao 《Integrative Medicine Discovery》 2025年第6期1-13,共13页
Jing Fang granules(JFG)are a modern Chinese medicinal formulation derived from Jing Fang Defeating Toxin San(JFDS).JFG primarily contains bioactive compounds such as flavonoids/flavonoid glycosides,coumarins and other... Jing Fang granules(JFG)are a modern Chinese medicinal formulation derived from Jing Fang Defeating Toxin San(JFDS).JFG primarily contains bioactive compounds such as flavonoids/flavonoid glycosides,coumarins and other components,which have various activities:anti-inflammatory,immune system regulation,antiviral,anti-aging,detoxification,and protection of the liver,lungs,and kidneys.JFG has broad potential therapeutic applications.The mechanisms of JFG’s actions are primarily associated with signaling pathways such as TLR4/NF-κB,PI3K/AKT,and MAPK.This article reviews the research progress on JFG,including chemical composition,pharmacologic effects,mechanism of action,safety,clinical application,etc.,serving as a foundation for future research and clinical applications. 展开更多
关键词 chemical composition clinical application Jing Fang granules pharmacological effect traditional Chinese herbal formula
暂未订购
Chemical Composition,Pharmacological Effects,and Clinical Applications of Danggui(Angelicae Sinensis Radix)
10
作者 Jiao Wu Jialong Zhang +1 位作者 Fangchao Tong Haichuan Yu 《Chinese Medicine and Natural Products》 2025年第4期199-205,共7页
As a traditional medicinal and edible herb,Danggui(Angelicae Sinensis Radix)exhibits pharmacological activities closely associated with its characteristic chemical components,such as volatile oils(e.g.,ligustilide),or... As a traditional medicinal and edible herb,Danggui(Angelicae Sinensis Radix)exhibits pharmacological activities closely associated with its characteristic chemical components,such as volatile oils(e.g.,ligustilide),organic acids(e.g.,ferulic acid),and polysaccharides.It demonstrates a wide range of pharmacological effects,including anti-inflammatory and immunomodulatory properties,cardiovascular and cerebrovascular protection,neuroprotective functions,blood glucose regulation,antitumor activity,and hematopoietic promotion.Clinically,Danggui(Angelicae Sinensis Radix)is often combined with other Chinese herbs to treat immune-related disorders,cardiovascular and cerebrovascular diseases,neurodegenerative conditions,diabetes,and cancer.Although existing studies have identified some active components,the mechanisms and pharmacological roles of many others remain underexplored.Future research should focus on systematically analyzing diverse active constituents such as flavonoids,coumarins,amino acids,bioactive peptides,trace elements,and vitamins.Integrating multiomics and molecular docking technologies will help elucidate key targets and molecular mechanisms underlying its anti-inflammatory,antioxidant,and immunomodulatory effects,thereby facilitating the development of precise therapies based on multicomponent synergy.Additionally,in-depth investigation of herb-pairing effects and establishment of scientific quality control standards are essential to expand clinical applications and enhance the medicinal value of this traditional herb. 展开更多
关键词 Danggui (Angelicae Sinensis Radix) chemical composition pharmacological effects clinical applications
原文传递
Chemical composition and biological activities of Lysimachia capillipes Hemsl
11
作者 Ran Guo Ruoming Li +3 位作者 Xiaomeng Zhang Wenhan Wang Yao Zhao Yu Chen 《Asian Journal of Traditional Medicines》 2025年第1期14-29,共16页
Lysimachia capillipes(L.capillipes)Hemsl,belong to primulaceae pearl vegetables genus,is a treasure in traditional Chinese medicine.It has the effects of invigorating qi and tonifying deficiency,dispelling wind and ac... Lysimachia capillipes(L.capillipes)Hemsl,belong to primulaceae pearl vegetables genus,is a treasure in traditional Chinese medicine.It has the effects of invigorating qi and tonifying deficiency,dispelling wind and activating blood,awakening the brain,relieving cough and regulating menstruation.With the development of modern medicine,the active components and therapeutic mechanisms of L.capillipes Hemsl have been gradually revealed.The present report systematically reviews the chemical composition and biological activities of L.capillipes Hemsl,to provide scientific basis and reference for detailed research on L.capillipes Hemsl. 展开更多
关键词 Lysimachia capillipes Hemsl capilliposide chemical composition biological activity
暂未订购
Research progress of chemical composition and pharmacological activity of Boenninghausenia sessilicarpa Lévl.
12
作者 Shuxing Tian Lan Zou +3 位作者 Yue Yang Qiaoyan Yang Fayun Zi Pan Zhang 《Asian Journal of Traditional Medicines》 2025年第4期195-207,共13页
Boenninghausenia sessilicarpa Lévl.is a commonly used folk medicine in southwest Yunnan.It has the effects of clearing heat and detoxifying,promoting qi circulation and activating blood circulation.It is used to ... Boenninghausenia sessilicarpa Lévl.is a commonly used folk medicine in southwest Yunnan.It has the effects of clearing heat and detoxifying,promoting qi circulation and activating blood circulation.It is used to treat various conditions such as colds,tonsillitis,mumps,lung-heat induced cough and asthma,abdominal distension and pain,pyelonephritis,gangrene of the extremities,low back pain,and bruises from falls and injuries.This paper summarizes recent research progress on the chemical constituents and pharmacological activities of Boenninghausenia sessilicarpa Lévl.,aiming to advance fundamental and clinical studies on this plant and provide a reference for enhanced medical utilization. 展开更多
关键词 boenninghausenia sessilicarpa Lévl. chemical composition pharmacological activity
暂未订购
Disparities in precipitation effects on PM_(2.5)mass concentrations and chemical compositions:Insights from online monitoring data in Chengdu 被引量:1
13
作者 Yi Li Li Zhou +7 位作者 Hefan Liu Song Liu Miao Feng Danlin Song Qinwen Tan Hongbin Jiang Sophia Zuoqiu Fumo Yang 《Journal of Environmental Sciences》 2025年第10期421-434,共14页
Precipitation plays a pivotal role in wet deposition,significantly affecting aerosol purification.The efficacy of precipitation in removing aerosols depends on its type and the characteristics of the particulates invo... Precipitation plays a pivotal role in wet deposition,significantly affecting aerosol purification.The efficacy of precipitation in removing aerosols depends on its type and the characteristics of the particulates involved.However,further research is necessary to fully understand how precipitation impacts PM_(2.5)components.This study utilized high-temporalresolution data on PM_(2.5),its components and meteorological factors to examine varying responses influenced by precipitation intensity and duration.The findings indicate that increased rainfall intensity and duration enhance PM_(2.5)and its constituents removal efficiency.Specifically,longer precipitation periods significantly improve PM_(2.5)purification,especially with drizzle and light rain.Moreover,there is a direct correlation between preprecipitation PM_(2.5)levels and its scavenging rates,with drizzle potentially exacerbating PM_(2.5)pollution under cleaner conditions(≤35μg/m^(3)).Seasonally,the efficacy of removing PM_(2.5)components varies notably in response to drizzle and light rain.In spring,higher PM_(2.5)levels after drizzlewere primarily due to increased organic carbon concentrations favored by higher relative humidity and lower pH conditions compared to other seasons,conducive to secondary organic aerosol production.Lower wind speeds and higher temperatures further contribute to water-soluble organic carbon accumulation.Daytime and nighttime precipitation exerted differing influences on PM_(2.5)components,particularly in spring where daytime drizzle and light rain significantly increased PM_(2.5)and its constituents,notably NO_(3)-,potentially associated with phase distribution changes between gas and aerosol phases in low-temperature,high-RH conditions compared to nighttime.These results propose a dualimpact mechanism of precipitation on PM_(2.5)and provide scientific basis for designing effective control strategies. 展开更多
关键词 PRECIPITATION PM_(2.5)mass concentrations Scavenging rate chemical components Chengdu
原文传递
High-resolution Simulation Dataset of Hourly PM_(2.5)Chemical Composition in China(CAQRA-aerosol)from 2013 to 2020 被引量:1
14
作者 Lei KONG Xiao TANG +14 位作者 Jiang ZHU Zifa WANG Bing LIU Yuanyuan ZHU Lili ZHU Duohong CHEN Ke HU Huangjian WU Qian WU Jin SHEN Yele SUN Zirui LIU Jinyuan XIN Dongsheng JI Mei ZHENG 《Advances in Atmospheric Sciences》 2025年第4期697-712,共16页
Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategi... Scientific knowledge on the chemical compositions of fine particulate matter(PM_(2.5)) is essential for properly assessing its health and climate effects,and for decisionmakers to develop efficient mitigation strategies.A high-resolution PM_(2.5) chemical composition dataset(CAQRA-aerosol)is developed in this study,which provides hourly maps of organic carbon,black carbon,ammonium,nitrate,and sulfate in China from 2013 to 2020 with a horizontal resolution of 15 km.This paper describes the method,access,and validation results of this dataset.It shows that CAQRA-aerosol has good consistency with observations and achieves higher or comparable accuracy with previous PM_(2.5) composition datasets.Based on CAQRA-aerosol,spatiotemporal changes of different PM_(2.5) compositions were investigated from a national viewpoint,which emphasizes different changes of nitrate from other compositions.The estimated annual rate of population-weighted concentrations of nitrate is 0.23μg m^(−3)yr^(−1) from 2015 to 2020,compared with−0.19 to−1.1μg m^(−3)yr^(−1) for other compositions.The whole dataset is freely available from the China Air Pollution Data Center(https://doi.org/10.12423/capdb_PKU.2023.DA). 展开更多
关键词 PM_(2.5)composition dataset black carbon organic carbon AMMONIUM NITRATE SULFATE
在线阅读 下载PDF
Geochemical Compositions and Transport Patterns of Surface Sediments from the Malacca Strait
15
作者 AI Lina LIU Shengfa +6 位作者 ZHANG Hui CAO Peng LI Xue QI Wenjing WU Kaikai MOHAMED Che Abd Rahim SHI Xuefa 《Journal of Ocean University of China》 2025年第6期1613-1623,共11页
The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical ... The Malacca Strait(MS)is a vital conduit for the exchange of water and sediment between the Indian Ocean and the Pacific Ocean,serving as a critical‘gateway'for sediment transport.Here,we present the geochemical characteristics of surface sediments in the MS to elucidate the relationship between terrestrial material inputs and modern oceanic dynamic transport processes in the strait.The results reveal that the MS can be divided into three distinct geochemical provinces.ProvinceⅠ,located in the central region of the strait,is characterized by residual deposits.The preservation of these residual deposits can be attributed to the restricted sediment supply and the relatively weaker modern sedimentary hydrodynamic conditions.ProvinceⅡ,situated to the north of ProvinceⅠ,exhibits provenance differences between its southern and northern regions.The northern region is primarily supplied by sediments originating from the eastern shelf of the Andaman Sea,whereas sediments derived from Sumatra and the Sunda Shelf are predominantly deposited in the southern part of ProvinceⅡ.ProvinceⅢextends along the western coast of the Malaysian Peninsula,with sediments primarily sourced from the Malaysian Peninsula and the Sunda Shelf,while contributions from Sumatra and the eastern shelf of the Andaman Sea are negligible.River sediments from the Malaysian Peninsula and Sumatra are transported northwestward along their respective coasts by prevailing currents,which also facilitate the transportation of Sunda Shelf sediments within the strait,while sediments from the eastern shelf of the Andaman Sea are delivered to the MS via southward coastal currents during the southwest monsoon period.The southward currents and well-developed eddies potentially impede the northward transport of sediments from the Sunda Shelf and restrict the distribution of Andaman Sea sediments within the strait.This study substantially enhances the understanding of source-to-sink processes in the Indo-Pacific region. 展开更多
关键词 surface sediment geochemical composition PROVENANCE SEDIMENTATION Malacca Strait
在线阅读 下载PDF
Chemical composition,biological activities and product development of Gastrodia elata:a review
16
作者 Liankui Wen Yuchen Jiang +5 位作者 Wenqi Wang Rongchen Zhu Jiahua Liu Yang He Fei Zheng Yuzhu Wu 《Food Science and Human Wellness》 2025年第10期3796-3820,共25页
Gastrodia elata Blume has a rich history of use in Asian.However,there is still a need for systematic analysis regarding the relationship and in-depth development between its components and functions.Through comprehen... Gastrodia elata Blume has a rich history of use in Asian.However,there is still a need for systematic analysis regarding the relationship and in-depth development between its components and functions.Through comprehensive analysis utilizing databases such as Pub Med,Web of Science,and Google Scholar,the practical components,biological activities,and product development of G.elata have been investigated.It has been found that the main active components of G.elata,such as gastrodin and G.elata polysaccharides,possess functionalities in improving conditions such as epilepsy,hypertension,and osteoporosis.These active components exhibit phenolic hydroxyl groups,molecular weight,conformation,and spatial arrangement,contributing to their enhanced ability to scavenge free radicals.Additionally,G.elata is known to have organic acids and esters,which exhibit potential immune regulatory and antiviral properties.Compounds with multiple acidic functional groups exhibit even more vigorous activity.Steroidal compounds likeβ-sitosterol,due to their presence of alcohol and ketone groups,along with a multi-ring structure,exhibit superior cholesterol-lowering activity.G.elata has already been recognized in the traditional chinese medicine and food homology list,showcasing its potential for development in line with the health demands of the current era.However,challenges regarding quality evaluation,peculiar odor,and the extraction process of the practical components still require immediate attention.Constructing a robust evaluation system and optimizing product processing techniques will be crucial for the future advancement of the G.elata industry. 展开更多
关键词 Gastrodia elata Blume chemical components Biological activities Product analysis
暂未订购
Prediction of Quality Markers(Q-Markers)for the Mongolian Medicine Naru-3 Based on Chemical Composition,Pharmacological Effects,and Network Pharmacology
17
作者 Ying En Liang Xu Jiaqi Yu 《Journal of Clinical and Nursing Research》 2025年第1期1-10,共10页
Naru Sanwei Pill,also known as Naru-3,a Mongolian medicine originating from Zhigao Pharmacopoeia,is a classic prescription used in the treatment of rheumatism.It is composed of Terminalia chebula,processed Aconitum ku... Naru Sanwei Pill,also known as Naru-3,a Mongolian medicine originating from Zhigao Pharmacopoeia,is a classic prescription used in the treatment of rheumatism.It is composed of Terminalia chebula,processed Aconitum kusnezoffii Reichb.,and Piper longum,and is known for its effects in eliminating“mucus,”relieving pain,and reducing swelling,with significant efficacy in treating joint effusion and lumbar pain.In recent years,researchers have summarized its chemical components and pharmacological effects,and employed network pharmacology methods based on the core theory of Traditional Chinese Medicine quality markers(Q-Markers)to analyze and predict its markers.The results identified potential Q-Markers for Naru-3,providing a scientific basis for quality control and further research. 展开更多
关键词 Mongolian medicine Naru-3 Network pharmacology Quality markers chemical components Pharmacological effects
在线阅读 下载PDF
Compositional fluctuation and local chemical ordering in multi-principal element alloys
18
作者 Evan Ma Jun Ding 《Journal of Materials Science & Technology》 2025年第17期233-244,共12页
1.Introduction Multi-principal element alloys(MPEAs),with compositions in the central region of the multicomponent phase diagram,have been dubbed"high-entropy alloys"(HEAs)in recent years[1-11].A more genera... 1.Introduction Multi-principal element alloys(MPEAs),with compositions in the central region of the multicomponent phase diagram,have been dubbed"high-entropy alloys"(HEAs)in recent years[1-11].A more general term currently accepted by the community for these MPEAs is complex concentrated alloys or compositionally complex alloys(CCAs)[12].These alloys are usually based on single-phase multi-principal element solid solutions,with no need or possibility to distinguish which species constitutes the solvent and which ones are solutes.This Viewpoint and Perspective article focuses on a salient feature in the internal structure of MPEAs,different from traditional metals and solvent-(dilute)solute solutions.Specifically,the unusual trait to be highlighted for these heavily concentrated solutions is their inherent chemical inhomogeneity on the nanoscale,in terms of the high propensity for compositional fluctuation and local chemical order. 展开更多
关键词 complex concentrated alloys local chemical ordering high entropy alloys compositionally complex alloys compositionally complex alloys ccas compositionally fluctuation multi principal element alloys nanoscale inhomogeneity
原文传递
From Biomass to Chiral Chemicals via Chemocatalysis:Advances and Prospects
19
作者 Shuguang Xu Shengqi Liao +1 位作者 Jianmei Li Changwei Hu 《Chinese Journal of Chemical Physics》 2026年第1期73-88,I0043,共17页
Optically pure chiral chemicals are important building blocks with widespread applications across mul-tiple scientific and industrial do-mains such as in pharmaceuticals,agrochemicals,and food,especially acting as pre... Optically pure chiral chemicals are important building blocks with widespread applications across mul-tiple scientific and industrial do-mains such as in pharmaceuticals,agrochemicals,and food,especially acting as precursors to synthesize biodegradable polymers.As an al-ternative to fossil resources,renew-able lignocellulosic biomass has been used to access chiral chemicals,due to the versatile inherent stere-ostructures and multiple functional groups,such as hydroxyl,carbonyl,and phenyl ether groups.Typically,as the two main units of(hemi)cel-lulose components in lignocellulosic biomass,D-xylose and D-glucose bear multiple chiral centers(e.g.,2R-3S-4R for D-xylose and 2R-3S-4R-5R for D-glucose).Lignin bearsβ-O-4 linkages,exhibiting(R,S/S,R)or(R,R/S,S)stereocenters at the side-chainαandβcarbon atoms.The valorization of biomass into optical-ly pure chiral chemicals is vital for developing a more sustainable future.This review discuss-es the production of typical chiral chemicals derived from biomass through chemocatalysis,including lactones(e.g.,R/S-valerolactone),carboxylic acids(e.g.,D/L-glyceric acid,D/L-lactic acid),polyols(e.g.,tetrose),furans,oligosaccharides,and others.Two strategies are generally employed.One approach involves first producing achiral platform chemicals from biomass,followed by the introduction of asymmetric catalysts to reconstruct stereocenters.The second relates to selectively preserving one or more inherent stereocenters in the natural biomass structure during complex cascade reactions in which biomass feedstock acts as a“chi-ral pool",thus eliminating the establishment of stereocenter.The feedstock,methods em-ployed,and enantioselectivity and applications of the target chiral chemicals are discussed.Despite these advances,the synthesis of optically pure chemicals from biomass is still in its in-fancy.The coming decade presents both extraordinary challenges and opportunities in biomass-derived chiral chemistry.Future research should be focused on:(1)integrating well-established asymmetric catalysis techniques and methods with biomass’s inherent chiral pools,presenting an unprecedented opportunity to expand the chemical space of sustainable chiral compounds;(2)mastering polyfunctional complexity of chiral chemicals through holis-tic utilization of biomass’multichiral centers;(3)unlocking lignin’s stereochemical treasury that represents the next frontier in biomass valorization. 展开更多
关键词 Biomass valorization Carbohydrates LIGNIN Chiral chemicals Enantioselectiv-ity
在线阅读 下载PDF
Chemically Engineered Hydroxyl-terminated Polybutadiene Yields Stable and High-strain Intrinsically Conductive Polyurethane Piezoresistive Sensors
20
作者 Li Zhou Guo-Xuan Ma +6 位作者 Wen-Xue Tian Wen-Cong Sun Shu-Miao Li Xiao-Ru Wang Wen-Chao Ji Yin-Yong Sun Chun-Xiang Li 《Chinese Journal of Polymer Science》 2026年第1期100-115,I0011,共17页
The development of intrinsically conductive piezoresistive sensors with high strain tolerance has garnered significant interest.While elastomeric polymers exhibit excellent strain capabilities,their utility in sensing... The development of intrinsically conductive piezoresistive sensors with high strain tolerance has garnered significant interest.While elastomeric polymers exhibit excellent strain capabilities,their utility in sensing applications has been limited by inherent challenges such as high electrical resistivity,poor aging resistance,and interfacial incompatibility.To address these limitations,hydroxyl-terminated polybutadiene(HTPB)-based polyurethane was chemically modified with acetylferrocene-polyaniline conductive moieties to enhance charge transport properties.Remarkably,this covalent functionalization endowed the resulting ferrocene-polyaniline hybrid polyurethane(FPHP)with a conductivity of2.33 n A at 1 V bias while preserving piezoresistive functionality.The FPHP demonstrated exceptional mechanical-electrical performance,achieving 254% elongation at break with strain-dependent gauge factors of 7.28(0%-12.5% strain,R^(2)=0.9504)and 19.66(12.5%-35.0% strain,R^(2)=0.9929).Further characterization revealed a rapid 0.60 s response time and stability over 3500 strain-release cycles at compression strain,underscoring its durability under repetitive loading.The FPHP sensor was capable of monitoring various human movements and recognizing writing signals.These advances establish a materials design paradigm for fabricating flexible sensors that synergistically integrate high deformability,tunable sensitivity,and robust operational stability,positioning FPHP as a promising candidate for next-generation wearable electronics and soft robotics. 展开更多
关键词 Piezoresistive sensor chemical modification Intrinsically conducting polyurethane Hydroxyl-terminated polybutadiene
原文传递
上一页 1 2 250 下一页 到第
使用帮助 返回顶部