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超高效液相色谱-电喷雾串联质谱法测定无糖糕点中9种甜味剂

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化学研究与应用 2024年第9期36卷 2169-2178页

作者：孙群刘川郭添荣廖梅蒋云露宫亚君宋娟成都市食品检验研究院国家市场监管重点实验室(新型食品原料监测评价) 四川成都611130 成都理工大学地质灾害防治与地质环境保护国家重点实验室四川成都610059

建立了超高效液相色谱-电喷雾串联质谱法(UPLc-ESI-MS/MS)快速测定网购无糖糕点中阿力甜、甜菊糖苷、甘草酸铵、甜蜜素、糖精钠、安赛蜜、阿斯巴甜、纽甜、三氯蔗糖的检测方法。样品采用75%甲醇水溶液提取,正己烷脱脂,HLB固相小柱净化,... 详细信息

建立了超高效液相色谱-电喷雾串联质谱法(UPLc-ESI-MS/MS)快速测定网购无糖糕点中阿力甜、甜菊糖苷、甘草酸铵、甜蜜素、糖精钠、安赛蜜、阿斯巴甜、纽甜、三氯蔗糖的检测方法。样品采用75%甲醇水溶液提取,正己烷脱脂,HLB固相小柱净化,经c_(18)柱(3.0mm×100mm,1.7μm)分离后,在多反应监测模式下测定,外标法定量。结果表明,9种甜味剂在相应质量浓度范围内线性关系良好,相关系数均大于0.998,检出限为0.003mg·kg~0.03mg·kg^(-1),方法回收率为78.7%~105.2%之间,相对标准偏差(n=6)为2.1%~10.3%。该方法简便快速,灵敏度高,实用性强,可用于无糖糕点中9种甜味剂的快速测定。

关键词：超高效液相色谱-电喷雾串联质谱无糖糕点甜味剂

Multi-scale investigation of short-range order and dislocation glide in MoNbTi and TaNbTi multi-principal element alloys

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npj computational Materials 2023年第1期9卷 1430-1442页

作者： Hui Zheng Lauren T.w.Fey Xiang-Guo Li Yong-Jie Hu Liang Qi chi chen Shuozhi Xu Irene J.Beyerlein Shyue Ping ong Department of NanoEngineering University of California San DiegoLa JollaCA 92093-0448USA Materials Department University of CaliforniaSanta BarbaraCA 93106-5050USA Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Materials Science and Engineering Drexel UniversityPhiladelphiaPA 19104USA Department of Mechanical Engineering University of CaliforniaSanta BarbaraCA 93106-5070USA

Refractory multi-principal element alloys(RMPEAs)are promising materials for high-temperature structural ***,we investigate the role of short-range ordering(SRO)on dislocation glide in the MoNbTi and TaNbTi RMPEAs using a multi-scale modeling *** carlo/molecular dynamics simulations with a moment tensor potential show that MoNbTi exhibits a much greater degree of SRO than TaNbTi and the local composition has a direct effect on the unstable stacking fault energies(USFEs).From mesoscale phase-field dislocation dynamics simulations,we find that increasing SRO leads to higher mean USFEs and stress required for dislocation *** gliding dislocations experience significant hardening due to pinning and depinning caused by random compositional fluctuations,with higher SRO decreasing the degree of USFE dispersion and hence,amount of ***,we show how the morphology of an expanding dislocation loop is affected by the applied stress.

关键词： alloys dislocation element

Solar-powered chemistry: Engineering low-dimensional carbon nitride-based nanostructures for selective cO_(2) conversion to c_(1)- c_(2) products

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InfoMat 2022年第1期4卷 40-104页

作者： Sue-Faye Ng Joel Jie Foo wee-Jun ong School of Energy and chemical Engineering Xiamen University MalaysiaSepangSelangorMalaysia center of Excellence for NaNo Energy&catalysis Technology(cONNEcT) Xiamen University MalaysiaSepangSelangorMalaysia college of chemistry and chemical Engineering Xiamen UniversityXiamenChina

cO_(2)capture and conversion has been prospected as an auspicious technology to simultaneously tackle the rise in global cO_(2)emission and produce valueadded fuels with the goal of accomplishing carbon neutrality.A sustainable route to achieve this is via the utilization of solar energy,thereby harnessing the abundant and nonexhaustive resource to shift our reliance away from rapidly depleting fossil *** carbon nitride(g-c_(3)N_(4))and its allotrope have earned its rank as a fascinating metal-free photocatalyst due to its superior stability,high surface-area-to-volume ratio,and tunable surface *** leveraging these properties,robust carbon nitride-based nanostructures are engineered for photocatalytic cO_(2)conversion to energy-rich c_(1)-c_(2) product,which is indispensable in the chemical ***,this review presents the latest panorama of experimental and computational research on tuning the local electronic,surface chemical coordination environment,charge dynamics and optical properties of low-dimensional carbon nitride and its allotropes toward highly selective and efficient cO_(2)*** name a few,structural engineering,point-defect engineering,heterojunction construction,and cocatalyst *** advance this frontier,critical insights are elucidated to establish the structure-performance relationship and unravel primary factors dictating the selectivity of c_(1)-c_(2) molecules from cO_(2)***-field assisted photocatalysis such as with electric(photoelectro-)and heat(photothermal)is discussed to uncover the synergistic contributions that drive the development in ***,future challenges and prospects are outlined for the potential application of solar-driven cO_(2)conversion,along with the scale-up strategy from the economic viewpoint toward the rational development of high-efficiency carbon nitride catalysts.

关键词： carbon nitride cO_(2)reduction external fields interfacial design nanostructure photocatalysis

蒙药光明盐四味汤散HPLc指纹图谱及2个成分含量测定研究

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中国民族医药杂志 2024年第1期30卷 44-47页

作者：于智远田向阳何春龙内蒙古医科大学药学院内蒙古呼和浩特010110

目的:建立光明盐四味汤散HPLc指纹图谱,测定没食子酸和胡椒碱含量,提高光明盐四味汤散的质量标准。方法:采用HPLc法,色谱柱为Agilent 5 Tc-c_(18)(4.6 mm×250 mm);流动相为0.1%磷酸水(A)-甲醇(B)梯度洗脱;流速为1 mL·min^(-1);紫外检... 详细信息

目的:建立光明盐四味汤散HPLc指纹图谱,测定没食子酸和胡椒碱含量,提高光明盐四味汤散的质量标准。方法:采用HPLc法,色谱柱为Agilent 5 Tc-c_(18)(4.6 mm×250 mm);流动相为0.1%磷酸水(A)-甲醇(B)梯度洗脱;流速为1 mL·min^(-1);紫外检测波长为300 nm;柱温为30℃;进样量为10 mL。结果:10批样品的HPLc图确定11个共有峰,计算相似度为0.995以上,3号峰为没食子酸,10号峰为胡椒碱。没食子酸在21.76~130.56范围内呈良好的线性关系,r=0.9997;胡椒碱在105.1~420.4平均加样回收率分别为98.73%和99.26%,RSD小于2%。结论:该方法简便、准确,可用于光明盐四味汤散的质量控制,提高该药质量标准。

关键词：光明盐四味汤散指纹图谱高效液相色谱法质量控制含量测定

Synthesis and mesomorphic behavior of benzothiazole-based liquid crystals having terminal methoxyl group

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chinese chemical Letters 2009年第12期20卷 1449-1452页

作者： Sie Tiong Ha Teck Ming Koh Siew Teng ong Yasodha Sivasothy Department of chemical Science Faculty of ScienceEngineering & TechnologyUniversiti Tunku Abdul RahmanJln UniversitiBandar Barat 31900 KamparPerakMalaysia Department of Science Faculty of Engineering & ScienceUniversiti Tunku Abdul RahmanJln Genting KlangSetapak 53300 Kuala LumpurMalaysia chemistry Department Faculty of ScienceUniversiti Malaya 50603 Kuala LumpurMalaysia

A homologous series of benzothiazole derivatives, 6-methoxy-2-（4-alkanoyloxybenzylidenamino）benzothiazoles, were synthesized and characterized using FT-IR, ^1H and ^13c NMR, mass spectrometry and elemental analysis. Enantiotropic nematic phase was observed throughout the entire series. Smectic c phase only emerged from the decanoyloxy derivative onwards. The terminal methoxyl group and the ester linkage influenced the mesomorphic behavior of the present series.

关键词： Benzothiazole Schiff bases Nematic Smectic c Liquid crystal

Adaptive and scalable load balancing for metadata server cluster in cloud-scale file systems

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Frontiers of computer Science 2015年第6期9卷 904-918页

作者： Quanqing xu Rajesh Vellore ARUMUGAM Khai Leong Yong Yonggang wEN Yew-Soon ong weiya XI Data Storage Institute Agency for Science Technology and Research Singapore 138632 Singapore School of computer Engineering Nanyang Technological University Singapore 639798 Singapore

Big data is an emerging term in the storage indus- try, and it is data analytics on big storage, i.e., cloud-scale storage. In cloud-scale （or EB-scale） file systems, load bal- ancing in request workloads across a metadata server cluster is critical for avoiding performance bottlenecks and improv- ing quality of services. Many good approaches have been pro- posed for load balancing in distributed file systems. Some of them pay attention to global namespace balancing, making metadata distribution across metadata servers as uniform as possible. However, they do not work well in skew request dis- tributions, which impair load balancing but simultaneously increase the effectiveness of caching and replication, in this paper, we propose cloud cache （c2）, an adaptive and scal- able load balancing scheme for metadata server cluster in EB-scale file systems. It combines adaptive cache diffusion and replication scheme to cope with the request load balanc- ing problem, and it can be integrated into existing distributed metadata management approaches to efficiently improve their load balancing performance. c2 runs as follows： 1） to run adaptive cache diffusion first, if a node is overloaded, load- shedding will be used; otherwise, load-stealing will be used; and 2） to run adaptive replication scheme second, if there is a very popular metadata item （or at least two items） causing a node be overloaded, adaptive replication scheme will be used,in which the very popular item is not split into several nodes using adaptive cache diffusion because of its knapsack prop- erty. By conducting performance evaluation in trace-driven simulations, experimental results demonstrate the efficiency and scalability of c2.

关键词： metadata management load balancing adaptivecache diffusion adaptive replication cloud-scale file systems

Point-to-face contact heterojunctions:Interfacial design of 0D nanomaterials on 2D g-c_(3)N_(4)towards photocatalytic energy applications

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carbon Energy 2022年第5期4卷 665-730页

作者： Xin-Quan Tan Sue-Faye Ng Abdul Rahman Mohamed wee-Jun ong School of Energy and chemical Engineering Xiamen University MalaysiaSelangor Darul EhsanMalaysia center of Excellence for NaNo Energy&catalysis Technology(cONNEcT) Xiamen University MalaysiaSelangor Darul EhsanMalaysia Low carbon Economy(LcE)Research Group School of Chemical EngineeringUniversiti Sains MalaysiaNibong TebalPulau PinangMalaysia State Key Laboratory of Physical chemistry of Solid Surfaces College of Chemistry and Chemical EngineeringXiamen UniversityXiamenFujianChina Shenzhen Research Institute of Xiamen University ShenzhenGuangdongChina

Green energy generation is an indispensable task to concurrently resolve fossil fuel depletion and environmental issues to align with the global goals of achieving carbon ***,a process that transforms solar energy into clean fuels through a photocatalyst,represents a felicitous direction toward ***-rich metal-free graphitic carbon nitride(g-c_(3)N_(4))is profiled as an attractive photocatalyst due to its fascinating properties,including excellent chemical and thermal stability,moderate band gap,visible light-active nature,and ease of ***,the shortcomings of g-c_(3)N_(4)include fast charge recombination and limited surface-active sites,which adversely affect photocatalytic *** the modification strategies,point-to-face contact engineering of 2D g-c_(3)N_(4)with 0D nanomaterials represents an innovative and promising synergy owing to several intriguing attributes such as the high specific surface area,short effective charge-transfer pathways,and quantum confinement *** review introduces recent advances achieved in experimental and computational studies on the interfacial design of 0D nanostructures on 2D g-c_(3)N_(4)in the construction of point-to-face heterojunction ***,0D materials such as metals,metal oxides,metal sulfides,metal selenides,metal phosphides,and nonmetals on g-c_(3)N_(4)with different charge-transfer mechanisms are systematically discussed along with controllable synthesis *** applications of 0D/2D g-c_(3)N_(4)-based photocatalysts are focused on solar-to-energy conversion via the hydrogen evolution reaction,the cO_(2)reduction reaction,and the N2 reduction reaction to evaluate the photocatalyst activity and elucidate reaction ***,future perspectives for developing high-efficiency 0D/2D photocatalysts are proposed to explore potential emerging carbon nitride allotropes,large-scale production,machine learning integration,and multidiscipli

关键词： 0D/2D heterojunction charge-transfer mechanisms g-c_(3)N_(4)nanosheets heterojunction interface photocatalysis solar-to-energy conversion

Vessel density and En-face segmentation of optical coherence tomography angiography to analyse corneal vascularisation in an animal model

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Eye and Vision 2019年第1期6卷 6-16页

作者： Kavya Devarajan wen Di Lee Hon Shing ong Nyein c.Lwin Jacqueline chua Leopold Schmetterer Jodhbir S.Mehta Marcus Ang Singapore Eye Research Institute SingaporeSingapore Singapore National Eye center SingaporeSingapore Eye-AcP Duke-NUS Graduate Medical SchoolSingaporeSingapore Department of clinical Pharmacology Medical University of ViennaViennaAustria center for Medical Physics and Biomedical Engineering Medical University of ViennaViennaAustria Nanyang Technological University SingaporeSingapore

Background:Optical coherence tomography angiography(OcTA)is a novel non-invasive angiography technology that has recently been extensively studied for its utility in anterior segment *** this study,we compared a split-spectrum amplitude decorrelation angiography(SSADA)OcTA and an optical micro-angiography(OMAG SD)OcTA system to current angiographic technique,indocyanine green angiography(IcGA),to assess corneal vascularisation in an animal ***:we imaged 16 rabbits,(one eye per animal)with corneal vascularisation using SSADA OcTA(AngioVue;Optovue Inc.,USA),OMAG OcTA(Angioscan;RS-3000 Nidek ***.,Japan)and IcGA in the same region of interest of the cornea at successive *** then analysed all scanned images for vessel density measurements and used paired t-tests and Bland-Altman plots to examine for significant *** en-face segmentation images from each of the OcTA scans were also extracted and were matched at every 50μm segmentation to be compared for vessel density at the respective ***:Bland-Altman plots revealed a good agreement between all three imaging techniques(P>0.05)for all vessel density measurements computed,and the ranges of 95%limit of agreement were acceptable from a clinical *** significant difference was reported,with IcGA(μ=16.52±8.94%)being more comparable to the OMAG OcTA(μ=16.23±9.51%;p=0.50)than the SSADA OcTA(μ=17.09±7.34%;p=0.33)***,a good correlation value(r>0.9)was obtained when comparing the vessel density measurements of the en-face segmentations between the OcTA ***:comparable vessel density quantification between the two OcTA systems,and with IcGA was *** analysis of the vasculature at different depths showed varied performance in the two OcTA systems relative to each *** implications of the study may help to aid in the development of better OcTA algorithms for the anterior segment and its use in clinical translational research.

关键词： OcTA corneal vascularisation Optical micro angiography Split-spectrum amplitude decorrelation angiography Vessel density Anterior segment En-face OcTA

Interfacial engineering of graphitic carbon nitride(g-c_3N_4)-based metal sulfide heterojunction photocatalysts for energy conversion: A review

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chinese Journal of catalysis 2019年第3期40卷 289-319页

作者： Yijie Ren Deqian Zeng wee-Jun ong School of Energy and chemical Engineering Xiamen University Malaysia Selangor Darul Ehsan 43900 Malaysia School of Resources Environment and Materials Guangxi University Nanning 530004 Guangxi China college of chemistry and chemical Engineering Xiamen University Xiamen 361005 Fujian China

As one of the most appealing and attractive technologies, photocatalysis is widely used as a promising method to circumvent the environmental and energy problems. Due to its chemical stability and unique physicochemical, graphitic carbon nitride (g-c3N4) has become research hotspots in the community. However, g-c3N4 photocatalyst still suffers from many problems, resulting in unsatisfactory photocatalytic activity such as low specific surface area, high charge recombination and insufficient visible light utilization. Since 2009, g-c3N4-based heterostructures have attracted the attention of scientists worldwide for their greatly enhanced photocatalytic performance. Overall, this review summarizes the recent advances of g-c3N4-based nanocomposites modified with transition metal sulfide (TMS), including (1) preparation of pristine g-c3N4,(2) modification strategies of g-c3N4,(3) design principles of TMS-modified g-c3N4 heterostructured photocatalysts, and (4) applications in energy conversion. what is more, the characteristics and transfer mechanisms of each classification of the metal sulfide heterojunction system will be critically reviewed, spanning from the following categories:(1) Type I heterojunction,(2) Type II heterojunction,(3) p-n heterojunction,(4) Schottky junction and (5) Z-scheme heterojunction. Apart from that, the application of g-c3N4-based heterostructured photocatalysts in H2 evolution, cO2 reduction, N2 fixation and pollutant degradation will also be systematically presented. Last but not least, this review will conclude with invigorating perspectives, limitations and prospects for further advancing g-c3N4-based heterostructured photocatalysts toward practical benefits for a sustainable future.

关键词： Graphitic carbon nitride Metal sulfide Photocatalysis Energy transformation water splitting Reduction of carbon dioxide Pollutant degradation Nitrogen fixation