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    题名 作者 年代 出处 被引量
1AN ANISOTROPIC NONCONFORMING FINITE ELEMENT METHOD FOR APPROXIMATING A CLASS OF NONLINEAR SOBOLEV EQUATIONS显示文摘各向异性的 nonconforming 有限元素方法为非线性的 Sobolev 方程的一个班被介绍。最佳的错误估计和 supercloseness 为半分离、充分分离的近似计划被获得,它与传统的有限元素方法一样。另外,全球 superconvergence 通过 postprocessing 技术被导出。数字实验被包括说明建议方法的可行性。[从作者抽象]Dongyang Shi Haihong Wang Yuepeng Du 2009Journal of Computational Mathematics2009,27,2:49
2Developing gene-tagged molecular markers for evaluation of genetic association of apple SWEET genes with fruit sugar accumulation显示文摘Sugar content is an important component of fruit quality.Although sugar transporters are known to be crucial for sugar accumulation,the role of genes encoding SWEET sugar transporters in fruit sugar accumulation remains elusive.Here we report the effect of the SWEET genes on fruit sugar accumulation in apple.A total of 25 MdSWEET genes were identified in the apple genome,and 9 were highly expressed throughout fruit development.Molecular markers of these 9 MdSWEET genes were developed and used for genotyping of 188 apple cultivars.The association of polymorphic MdSWEET genes with soluble sugar content in mature fruit was analyzed.Three genes,MdSWEET2e,MdSWEET9b,and MdSWEET15a,were significantly associated with fruit sugar content,with MdSWEET15a and MdSWEET9b accounting for a relatively large proportion of phenotypic variation in sugar content.Moreover,both MdSWEET9b and MdSWEET15a are located on chromosomal regions harboring QTLs for sugar content.Hence,MdSWEET9b and MdSWEET15a are likely candidates regulating fruit sugar accumulation in apple.Our study not only presents an efficient way of implementing gene functional study but also provides molecular tools for genetic improvement of fruit quality in apple-breeding programs.Qiaoling Zhen Ting Fang Qian Peng Liao Liao Li Zhao Albert Owiti Yuepeng Han 2018Horticulture Research2018,5,1:12
3Review of low timing jitter mode-locked fiber lasers and applications in dual-comb absolute distance measurement显示文摘Passively mode-locked fiber lasers emit femtosecond pulse trains with excellent short-term stability. The quantum-limited timing jitter of a free running femtosecond erbium-doped fiber laser working at room temperature is considerably below one femtosecond at high Fourier frequency. The ultrashort pulse train with ultralow timing jitter enables absolute time-of-flight measurements based on a dual-comb implementation, which is typically composed of a pair of optical frequency combs generated by femtosecond lasers. Dead-zone-free absolute distance measurement with sub-micrometer precision and kHz update rate has been routinely achieved with a dual-comb configuration, which is promising for a number of precision manufacturing applications, from large step-structure measurements prevalent in microelectronic profilometry to three coordinate measurements in large-scale aerospace manufacturing and shipbuilding. In this paper, we first review the sub-femtosecond precision timing jitter characterization methods and approaches for ultralow timing jitter mode-locked fiber laser design. Then, we provide an overview of the state-of-the-art dual-comb absolute ranging technology in terms of working principles, experimental implementations, and measurement precisions. Finally, we discuss the impact of quantum-limited timing jitter on the dual-comb ranging precision at a high update rate. The route to highprecision dual-comb range finder design based on ultralow jitter femtosecond fiber lasers is proposed.Haosen Shi Youjian Song Runmin Li Yuepeng Li Hui Cao Haochen Tian Bowen Liu Lu Chai Minglie Hu 2018Nanotechnology and Precision Engineering2018,1,4:9
4Investigation of benzylisoquinoline alkaloid biosynthetic pathway and its transcriptional regulation in lotus显示文摘Lotus predominantly accumulates benzylisoquinoline alkaloids(BIAs),but their biosynthesis and regulation remain unclear.Here,we investigated structural and regulatory genes involved in BIA accumulation in lotus.Two clustered CYP80 genes were identified to be responsible for the biosynthesis of bis-BIAs and aporphine-type BIAs,respectively,and their tissue-specific expression causes divergence in alkaloid component between leaf and embryo.In contrast with the common(S)-reticuline precursor for most BIAs,aporphine alkaloids in lotus leaf may result from the(S)-N-methylcoclaurine precursor.Structural diversity of BIA alkaloids in the leaf is attributed to enzymatic modifications,including intramolecular C–C phenol coupling on ring A and methylation and demethylation at certain positions.Additionally,most BIA biosynthetic pathway genes show higher levels of expression in the leaf of high-BIA cultivar compared with low-BIA cultivar,suggesting transcriptional regulation of BIA accumulation in lotus.Five transcription factors,including three MYBs,one ethylene-responsive factor,and one basic helix–loop–helix(bHLH),were identified to be candidate regulators of BIA biosynthesis in lotus.Our study reveals a BIA biosynthetic pathway and its transcriptional regulation in lotus,which will enable a deeper understanding of BIA biosynthesis in plants.Xianbao Deng Li Zhao Ting Fang Yaqian Xiong Collins Ogutu Dong Yang Sornkanok Vimolmangkang Yanling Liu Yuepeng Han 2018Horticulture Research2018,5,1:8
5Copper base materials prepared by gel-casting process显示文摘Gel-casting process was developed as a new molding process in the field of copper base powder metallurgy to manufacture metal parts with excellent performance and complex shapes.Through changing the parameters of gel-casting process,such as dispersant and solid loading,the corresponding effects on the rheology of Cu slurries,molding and sintering behaviors were studied.The results show that the viscosity of Cu slurries was significantly reduced with an increase in dispersant.The most appropriate solid loading was found to be 61% and the sintering temperature was 910°C in these experiments.After the optimization of parameters of gel-casting process,copper composite parts with relatively high density and better properties were obtained.LIU Weihua JIA Chengchang SHI Yantao HAN Yuepeng 2008Rare Metals2008,27,1:7
6An imine-linked covalent organic framework as the host material for sulfur loading in lithium–sulfur batteries显示文摘Lithium–sulfur(Li–S) batteries have high theoretical specific capacity, providing new opportunities for the next generation of secondary battery. Covalent organic framework(COF) as a new porous crystalline material has been used as the host material in Li–S battery to improve the cell's cycling stability. In this paper, an imine-linked TAPB-PDA-COF was applied as the host material for sulfur loading(60%) in Li–S battery. The TAPB-PDA-COF has a beehive-like morphology with high thermal stability(up to 500 ℃).In the electrochemical experiment, the performance of the composite cathode with acetylene black(AB) and super-P(S-P) as the conductive additives was studied individually. The initial discharge capacity under 0.2 A/g current density was 991 mAh/g and 1357 mAh/g for TAPB-PDA-COF/S@A-B and TAPB-PDACOF/S@S-P, respectively. The better result of S-P based cathode than A-B could be due to the better conductivity of the S-P, as proved by the EIS results. When further increased the current density to 2 A/g,the S-P based composite cathode can still deliver a comparable initial discharge capacity of 630 and 274 mAh/g capacity remained after 940 cycles. This results will inspire researchers develop more suitable conductive additives together with the host materials for high performance Li–S battery.Jianyi Wang Liping Si Qin Wei Xujia Hong Ligui Lin Xin Li Jingyi Chen Peibiao Wen Yuepeng Cai 2019Journal of Energy Chemistry2019,28,1:7
7Determination of quorum-sensing signal substances in water and solid phases of activated sludge systems using liquid chromatography–mass spectrometry显示文摘The detection of acyl homoserine lactones(AHLs) in activated sludge is essential for clarifying their function in wastewater treatment processes. An LC–MS/MS method was developed for the detection of AHLs in both the aqueous and solid phases of activated sludge. In addition, the effects of proteases and extracellular polymeric substances(EPS) on the detection of AHLs were evaluated by adding protease inhibitors and extracting EPS,respectively. Recoveries of each AHL were improved by adding 50 μL of protease inhibitor,and recoveries were also improved from 0 to 56.9% to 24.2%–105.8% by EPS extraction.Applying the developed method to determine the type and concentration of AHLs showed that C4-HSL, C_6-HSL, C_8-HSL and 3-oxo-C_8-HSL were widely detected in a suspended activated sludge system. The dominant AHL was C_8-HSL, with a highest concentration of304.3 ng/L. C_4-HSL was mainly distributed in the aqueous phase, whereas C_6-HSL, C_8-HSL and 3-oxo-C_8-HSL were preferentially distributed in the sludge phase.Yuepeng Sun Kai He Qidong Yin Shinya Echigo Guangxue Wu Yuntao Guan 2018Journal of Environmental Sciences2018,30,7:6
8Reduced representation genome sequencing reveals patterns of genetic diversity and selection in apple显示文摘Identifying DNA sequence variations is a fundamental step towards deciphering the genetic basis of traits of interest.Here,a total of 20 cultivated and 10 wild apples were genotyped using specific-locus amplified fragment sequencing,and 39,635 single nucleotide polymorphisms with no missing genotypes and evenly distributed along the genome were selected to investigate patterns of genome-wide genetic variations between cultivated and wild apples.Overall,wild apples displayed higher levels of genetic diversity than cultivated apples.Linkage disequilibrium(LD) decays were observed quite rapidly in cultivated and wild apples,with an r^2-value below 0.2 at 440 and 280 bp,respectively.Moreover,bidirectional gene flow and different distribution patterns of LD blocks were detected between domesticated and wild apples.Most LD blocks unique to cultivated apples were located within QTL regions controlling fruit quality,thus suggesting that fruit quality had probably undergone selection during apple domestication.The genome of the earliest cultivated apple in China,Nai,was highly similar to that of Malus sieversii,and contained a small portion of genetic material from other wild apple species.This suggested that introgression could have been an important driving force during initial domestication of apple.These findings will facilitate future breeding and genetic dissection of complex traits in apple.Baiquan Ma Liao Liao Qian Peng Ting Fang Hui Zhou Schuyler S. Korban Yuepeng Han 2017Journal of Integrative Plant Biology2017,59,3:6
9Enhanced atmospheric phosphorus deposition in Asia and Europe in the past two decades显示文摘磷是植物生长必需的元素,磷缺乏将限制植被生产力及碳汇功能.为厘清全球大气磷沉降的时空格局,本文收集了1959-2020年发表的396条观测资料.结果发现,全球大气磷沉降的几何均值为0.32 kg ha~(-1)yr~(-1),全球大气磷库约4.4 Tg yr~(-1).与1959-2000年相比,近20年亚洲和欧洲大气磷沉降呈现上升趋势,主要来源是农业活动,沙尘传输和燃烧源排放.碳中和背景下,清洁空气行动是否会改变磷沉降的途径和形态,进而影响到生态系统的结构和功能,是需要回答的科学问题.Yuepeng Pan Bowen Liu Jing Cao Jin Liu Shili Tian Enzai Du 2021Atmospheric and Oceanic Science Letters2021,14,5:5
10Fucoxanthin induces growth arrest and apoptosis in human bladder cancer T24 cells by up-regulation of p21 and down-regulation of mortalin显示文摘Fucoxanthin,自然类胡萝卜素,被报导了在人的结肠癌房间,人的前列腺癌症房间,人的白血病房间,和人的上皮的颈的癌症房间举办反癌症活动。这研究被承担把 fucoxanthin 的分子的机制与人的膀胱癌症 T24 房间线作比较。 MTT 分析结果证明 5 和 10 M fucoxanthin 在生长拘捕在 G 0/G1伴随的一个剂量依赖者和时间依赖者举止禁止了 T24 房间的增长房间周期的阶段,被 p21 的起来规定调停,cyclin依赖的 kinase ( CDK )禁止的蛋白质和 CDK-2 , CDK-4 , cyclin D1 ,和 cyclin E 的下面规定。另外, 20 和 40 M fucoxanthin 由 mortalinp53 建筑群的废除和原子变异类型的 p53 的复活导致了 T24 房间的 apoptosis,它也让肿瘤 suppressor 作为野类型的 p53 工作。所有这些结果证明 T24 房间上的 fucoxanthin 的反癌症活动被 p21 的起来规定经由在 mortalin ,它是的表示水平,一个压力管理者和热的一个成员震惊的减少在低剂量和 apoptosis 在 G 0/G1阶段与房间周期拘捕联系蛋白质 70 ,在高剂量由劈开的 caspase-3 的起来规定列在后面。Linbo Wang Yang Zeng Ye Liu Xuansheng Hu Shuhong Li Yuepeng Wang Ling Li Zhongfang Lei Zhenya Zhang 2014Acta Biochimica et Biophysica Sinica2014,46,10:5
11A gelatin-based artificial SEI for lithium deposition regulation and polysulfide shuttle suppression in lithium-sulfur batteries显示文摘Lithium-sulfur(Li-S) battery is one of the best candidates for the next-generation energy storage system due to its high theoretical capacity(1675 mA h-1),low cost and environment friendliness.However,lithium(Li) dendrites formation and polysulfide shuttle effect are two major challenges that limit the commercialization of Li-S batteries.Here we design a facile bifunctional interlayer of gelatin-based fibers(GFs),aiming to protect the Li anode surface from the dendrites growth and also hinder the polysulfide shuttle effect.We reveal that the 3D structural network of GFs layer with abundant polar sites helps to homogenize Li-ion flux,leading to uniform Li-ion deposition.Meanwhile,the polar moieties also immobilize the lithium polysulfides and protect the Li metal from the side-reaction.As a result,the anodeprotected batteries have shown significantly enhanced performance.A high coulombic efficiency of 96% after 160 cycles has been achieved in the Li-Cu half cells.The Li-Li symmetric cells exhibit a prolonged lifespan for 800 h with voltage hysteresis(10 mV).With the as-prepared GFs layer,the Li-S battery shows approximately 14% higher capacity retention than the pristine battery at 0.5 C after 100 cycles.Our work presents that this gelatin-based bi-functional interlayer provides a viable strategy for the manufacturing of advanced Li-S batteries.Naseem Akhtar Xiaogang Sun Muhammad Yasir Akram Fakhar Zaman Weikun Wang Anbang Wang Long Chen Hao Zhang Yuepeng Guan Yaqin Huang 2021Journal of Energy Chemistry2021,30,1:5
12氮沉降模拟实验亟待研究大气氨浓度增加的影响显示文摘大气活性氮污染及其过量沉降是全球变化重要议题。为研究氮沉降对自然生态系统结构和功能的影响,基于喷淋加氮的控制实验在草地或林下广泛开展。该实验体系假定氮沉降是通过增加土壤氮的有效性从而影响整个生态系统,没有考虑植被与大气活性氮的相互作用,也未能反映氮沉降以干沉降为主的自然过程。考虑到大气氨是氮沉降的主要前体物,且全球氨气浓度呈现上升趋势,未来的氮沉降模拟实验亟待研究氨气干沉降的重要影响,以期更加完整的刻画大气氮沉降过程及其生态环境效应。PAN Yuepeng TIAN Shili WU Dianming XU Wen ZHU Xiaying LIU Chunyan LI Dejun FANG Yunting DUAN Lei LIU Xuejun WANG Yuesi 2020Atmospheric and Oceanic Science Letters2020,13,3:5
13Unraveling a genetic roadmap for improved taste in the domesticated apple显示文摘Although taste is an important aspect of fruit quality, an understanding of its genetic control remains elusive in apple and other fruit crops. In this study, we conducted genomic sequence analysis of 497 Malus accessions and revealed erosion of genetic diversity caused by apple breeding and possible independent domestication events of dessert and cider apples. Signatures of selection for fruit acidity and size, but not for fruit sugar content, were detected during the processes of both domestication and improvement. Furthermore, we found that single mutations in major genes affecting fruit taste, including Ma1, MdTDT, and MdSOT2, dramatically decrease malate, citrate, and sorbitol accumulation, respectively, and correspond to important domestication events. Interestingly, Ma1 was identified to have pleiotropic effects on both organic acid content and sugar:acid ratio, suggesting that it plays a vital role in determining fruit taste. Fruit taste is unlikely to have been negatively affected by linkage drag associated with selection for larger fruit that resulted from the pyramiding of multiple genes with minor effects on fruit size. Collectively, our study provides new insights into the genetic basis of fruit quality and its evolutionary roadmap during apple domestication, pinpointing several candidate genes for genetic manipulation of fruit taste in apple.Liao Liao Weihan Zhang Bo Zhang Ting Fang Xiao-Fei Wang Yarning Cai Collins Ogutu Lei Gao Gang Chen Xiaoqing Nie Jinsheng Xu Quanyan Zhang Yiran Ren Jianqiang Yu Chukun Wang Cecilia H.Deng Baiquan Ma Beibei Zheng Chun-Xiang You Da-Gang Hu Richard Espley Kui Lin-Wang Jia-Long Yao Andrew C.Allan Awais Khan Schuyler S.Korban Zhangjun Fei Ray Ming Yu-Jin Hao Li Li Yuepeng Han 2021Molecular Plant2021,14,9:5
14A Review on Artificial Micro/Nanomotors for Cancer-Targeted Delivery, Diagnosis, and Therapy显示文摘Micro/nanomotors have been extensively explored for efficient cancer diagnosis and therapy,as evidenced by significant breakthroughs in the design of micro/nanomotors-based intelligent and comprehensive biomedical platforms.Here,we demonstrate the recent advances of micro/nanomotors in the field of cancer-targeted delivery,diagnosis,and imaging-guided therapy,as well as the challenges and problems faced by micro/nanomotors in clinical applications.The outlook for the future development of micro/nanomotors toward clinical applications is also discussed.We hope to highlight these new advances in micro/nanomotors in the field of cancer diagnosis and therapy,with the ultimate goal of stimulating the successful exploration of intelligent micro/nanomotors for future clinical applications.Jiajia Wang Renfeng Dong Huiying Wu Yuepeng Cai Biye Ren 2020Nano-Micro Letters2020,12,1:5
15Regenerative Role of Soil Seed Banks of Different Successional Stages in A Saline-alkaline Grassland in Northeast China显示文摘Soil seed banks can act as a potential seed source for natural revegetation and restoration. However, in a saline-alkaline grassland, it remains unclear how the stages of vegetation succession affect the characteristics of soil seed banks and the potential of soil seed banks of different successional stages for vegetation restoration. In this study, seasonal changes of the soil seed bank, and seed production and dispersal dynamics along degradation successional gradients were investigated in a saline-alkaline grassland in Northeast China, where the dominant grass during the 1960 s, Leymus chinensis was replaced with the secondary successional order of Puccinellia chinampoensis, Chloris virgata, and Suaeda salsa, together with bare patches. It was found that the soil seed bank composition varied according to the changing vegetation and had the highest species richness(7–16) in the climax successional stage, but had a low S?rensen similarity(0.22–0.37) with the aboveground vegetation. There was a high seed density of the soil seed bank(21 062–62 166/m2 in August and December) and also high S?rensen similarity index values(0.47–0.60) in the secondary successional stages of P. chinampoensis, C. virgata, and S. salsa. In bare patches, there were many seeds in the soil seed bank and some seedlings also appeared in the aboveground vegetation, indicating the existence of a persistent soil seed bank. Seed density and species richness differed substantially among the different successional stages, which was related to the reproductive characteristics of the standing plants in vegetation communities. Due to the lack of propagules of perennial species, especially the climax species of L. chinensis, in the soil, the successful restoration of the degraded saline-alkaline grassland was not possible. The study proved that in a degraded saline-alkaline grassland dominated by biennial or annual species, the soil seed bank was important for the revegetation of the current dominant plants, but not for the restoration of the original target species. Therefore, it is necessary to induce seeds or other propagules of the target perennial species.MA Hongyuan LI Jingpeng YANG Fan Lü Xiaotao PAN Yuepeng LIANG Zhengwei 2018Chinese Geographical Science2018,28,4:5
16Hot deformation behavior of FGH96 superalloys显示文摘The hot deformation behavior of FGH96 superalloys at 1070-1170°C and 5×10?4-2×10?1 s?1 were investigated by means of the isothermal compression tests at a Gleeble-1500 thermal mechanical simulator. The results show that dynamic recovery acts as the main softening mechanism below 2×10?3 s?1, whereas dynamic recrystallization acts as the main softening mechanism above 2×10?3 s?1 during deformation; the temperature increase caused by the deformation and the corresponding softening stress is negligible; the thermal-mechanical constitutive model to describe the hot deformation behavior is given, and the value of the apparent deformation activation energy (Qdef ) is determined to be 354.93 kJ/mol.Jiantao Liu Guoquan Liu Benfu Hu Yuepeng Song Ziran Qin Yiwen Zhang 2006Journal of University of Science and Technology Beijing2006,13,4:4
17Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia显示文摘While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly,aerosol ammonium nitrate remains high in East China.As the high nitrate abundances are strongly linked with ammonia,reducing ammonia emissions is becoming increasingly important to improve the air quality of China.Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions,long-term surface observation of ammonia concentrations are sparse.In addition,there is still no consensus on whether agricultural or non-agricultural emissions dominate the urban ammonia budget.Identifying the ammonia source by nitrogen isotope helps in designing a mitigation strategy for policymakers,but existing methods have not been well validated.Revisiting the concentration measurements and identifying source apportionment of atmospheric ammonia is thus an essential step towards reducing ammonia emissions.Yuepeng PAN Mengna GU Yuexin HE Dianming WU Chunyan LIU Linlin SONG Shili TIAN Xuemei LÜ Yang SUN Tao SONG Wendell WWALTERS Xuejun LIU Nicholas AMARTIN Qianqian ZHANG Yunting FANG Valerio FERRACCI Yuesi WANG 2020Advances in Atmospheric Sciences2020,37,9:4
18Chemical characteristics,oxidative potential,and sources of PM_(2.5)in wintertime in Lahore and Peshawar,Pakistan显示文摘The chemical characteristics,oxidative potential,and sources of PM_(2.5)were analyzed at the urban sites of Lahore and Peshawar,Pakistan in February 2019.Carbonaceous species,water soluble ions,and metal elements were measured to investigate the chemical composition and sources of PM_(2.5).The dithiothreitol(DTT)consumption rate was measured to evaluate the oxidative potential of PM_(2.5).Both cities showed a high exposure risk of PM_(2.5)regarding its oxidative potential(DTT v).Carbonaceous and some of the elemental species of PM_(2.5)correlated well with DTT v in both Lahore and Peshawar.Besides,the DTT v of PM_(2.5)in Lahore showed significant positive correlation with most of the measured water soluble ions,however,ions were DTT-inactive in Peshawar.Due to the higher proportions of carbonaceous species and metal elements,Peshawar showed higher mass-normalized DTT activity of PM_(2.5)compared to Lahore although the average PM_(2.5)concentration in Peshawar was lower.The high concentrations of toxic metals also posed serious non-carcinogenic and carcinogenic risks to the residents of both cities.Principle component analysis coupled with multiple linear regression was applied to investigate different source contributions to PM_(2.5)and its oxidative potential.Mixed sources of traffic and road dust resuspension and coal combustion,direct vehicle emission,and biomass burning and formation of secondary aerosol were identified as the major sources of PM_(2.5)in both cities.The findings of this study provide important data for evaluation of the potential health risks of PM_(2.5)and for formulation of efficient control strategies in major cities of Pakistan.Mushtaq Ahmad Qing Yu Jing Chen Siming Cheng Weihua Qin Yuepeng Zhang 2021Journal of Environmental Sciences2021,33,4:4
19Te0.045S0.955PAN composite with high average discharge voltage for Li–S battery显示文摘As a sulfur-containing cathode material,sulfide polyacrylonitrile(SPAN)is expected to be used for longlife lithium-sulfur battery because there is no shuttle effect occurred in its charge process.However,its specific capacity and discharge potential need to be further improved to satisfy the urgent demands for high-performance batteries.In this paper,Te0.045S0.955PAN composite was synthesized by co-heating TexS1-x and PAN,and the superior electrochemical performance to that of SPAN was obtained because of doping Te with high conductivity.The as-prepared Te0.045S0.955PAN composite possessed the specific capacity of 675 mAh g^-1 after 100 cycles at the current density of 0.1 A g^-1 with high capacity retention of96.6%compared to the second cycle.Especially,during cycling,Te0.045S0.955PAN showed average discharge voltages of 1.88-1.91 V,which were higher than 1.85-1.88 V for SPAN at the same current density.Thus doping Te provides a new strategy for increasing the energy density of SPAN.Ke Wang Yuepeng Guan Zhaoqing Jin Weikun Wang Anbang Wang 2019Journal of Energy Chemistry2019,28,12:3
20δ^(15)N-stable isotope analysis of NH_(x): An overview on analytical measurements, source sampling and its source apportionment显示文摘Agricultural sources and non-agricultural emissions contribute to gaseous ammonia(NH_(3))that plays a vital role in severe haze formation.Qualitative and quantitative contributions of these sources to ambient PM_(2.5)(particulate matter with an aerodynamic equivalent diameter below 2.5µm)concentrations remains uncertain.Stable nitrogen isotopic composition(δ^(15)N)of NH_(3)and NH_(4)+(δ^(15)N(NH_(3))andδ^(15)N(NH_(4)+),respectively)can yield valuable information about its sources and associated processes.This review provides an overview of the recent progress in analytical techniques forδ^(15)N(NH_(3))andδ^(15)N(NH_(4)+)measurement,sampling of atmospheric NH_(3)and NH_(4)+in the ambient air and their sources signature(e.g.,agricultural vs.fossil fuel),and isotope-based source apportionment of NH_(3)in urban atmosphere.This study highlights that collecting sample that are fully representative of emission sources remains a challenge in fingerprintingδ^(15)N(NH_(3))values of NH_(3)emission sources.Furthermore,isotopic fractionation during NH_(3)gas-to-particle conversion under varying ambient field conditions(e.g.,relative humidity,particle pH,temperature)remains unclear,which indicates more field and laboratory studies to validate theoretically predicted isotopic fractionation are required.Thus,this study concludes that lack of refinedδ^(15)N(NH_(3))fingerprints and full understanding of isotopic fractionation during aerosol formation in a laboratory and field conditions is a limitation for isotope-based source apportionment of NH_(3).More experimental work(in chamber studies)and theoretical estimations in combinations of field verification are necessary in characterizing isotopic fractionation under various environmental and atmospheric neutralization conditions,which would help to better interpret isotopic data and our understanding on NH_(x)(NH_(3)+NH_(4)+)dynamics in the atmosphere.Noshan Bhattarai Shuxiao Wang Yuepeng Pan Qingcheng Xu Yanlin Zhang Yunhua Chang Yunting Fang 2021Frontiers of Environmental Science & Engineering2021,15,6:3
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