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Some studies on stochastic optimization based quantitative risk management
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作者 HU Zhaolin 《运筹学学报(中英文)》 北大核心 2025年第3期135-159,共25页
Risk management often plays an important role in decision making un-der uncertainty.In quantitative risk management,assessing and optimizing risk metrics requires eficient computing techniques and reliable theoretical... Risk management often plays an important role in decision making un-der uncertainty.In quantitative risk management,assessing and optimizing risk metrics requires eficient computing techniques and reliable theoretical guarantees.In this pa-per,we introduce several topics on quantitative risk management and review some of the recent studies and advancements on the topics.We consider several risk metrics and study decision models that involve the metrics,with a main focus on the related com-puting techniques and theoretical properties.We show that stochastic optimization,as a powerful tool,can be leveraged to effectively address these problems. 展开更多
关键词 stochastic optimization quantitative risk management risk measure computing technique statistical property
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RPSR1,a major quantitative trait locus for Pythium stalk rot resistance in maize 被引量:2
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作者 Shengfeng He Junbin Chen +4 位作者 Chuang Liu Dandan Liu Lei Wang Canxing Duan Wangsheng Zhu 《The Crop Journal》 2025年第1期51-61,共11页
Pythium stalk rot(PSR)is a destructive disease of maize,severely affecting yield and grain quality.The identification of quantitative trait loci(QTL)or genes for resistance to PSR forms the basis of diseaseresistant h... Pythium stalk rot(PSR)is a destructive disease of maize,severely affecting yield and grain quality.The identification of quantitative trait loci(QTL)or genes for resistance to PSR forms the basis of diseaseresistant hybrids breeding.In this study,a major QTL,Resistance to Pythium stalk rot 1(RPSR1),was identified from a set of recombinant inbred lines derived from MS71 and POP.Using a recombinant progeny testing strategy,RPSR1 was fine-mapped in a 472 kb interval.Through candidate gene expression,gene knock-down and knock-out studies,a leucine-rich repeat receptor-like kinase gene,PEP RECEPTOR 2(ZmPEPR2),was assigned as a PSR resistance gene.These results provide insights into the genetic architecture of resistance to PSR in maize,which should facilitate breeding maize for resistance to stalk rot. 展开更多
关键词 MAIZE Pythium stalk rot quantitative trait loci(QTL) LRR-RLK ZmPEPR2
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Operando quantitatively analyses of polarizations in all-vanadium flow batteries 被引量:1
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作者 Zhenyu Wang Jing Sun +8 位作者 Jiadong Shen Zixiao Guo Xiaosa Xu Jin Li Jiayou Ren Yiju Li Tianshuai Wang Xinzhuang Fan Tianshou Zhao 《Journal of Energy Chemistry》 2025年第6期178-184,I0005,共8页
All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential ... All-vanadium flow batteries(VFBs)are one of the most promising large-scale energy storage technologies.Conducting an operando quantitative analysis of the polarizations in VFBs under different conditions is essential for developing high power density batteries.Here,we employ an operando decoupling method to quantitatively analyze the polarizations in each electrochemical and chemical reaction of VFBs under different catalytic conditions.Results show that the reduction reaction of V^(3+)presents the largest activation polarization,while the reduction reaction of VO_(2)^(+)primarily contributes to concentration polarizations due to the formation of the intermediate product V_(2)O_(3)^(3+).Additionally,it is found that the widely used electrode catalytic methods,incorporating oxygen functional groups and electrodepositing Bi,not only enhance the reaction kinetics but also exacerbate concentration polarizations simultaneously,especially during the discharge process.Specifically,in the battery with the high oxygen-containing electrodes,the negative side still accounts for the majority of activation loss(75.3%)at 200 mA cm^(-2),but it comes down to 36,9% after catalyzing the negative reactions with bismuth.This work provides an effective way to probe the limiting steps in flow batteries under various working conditions and offers insights for effectively enhancing battery performance for future developments. 展开更多
关键词 Vanadium flow battery quantitative analysis Polarization Oxygen functional groups BISMUTH
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Quantitative insight into fracture distribution during supercritical CO_(2)fracturing in tight sandstone formation 被引量:1
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作者 Bing Yang Hai Huang +5 位作者 Qian-Qian Ren Hai-Zhu Wang Bin Wang Jun Ni Yong Zheng Wen-Tong Zhang 《Petroleum Science》 2025年第4期1670-1685,共16页
Supercritical CO_(2)(SC-CO_(2))fracturing stands out a promising waterless stimulation technique in the development of unconventional resources.While numerous studies have delved into the inducedfracture mechanism of ... Supercritical CO_(2)(SC-CO_(2))fracturing stands out a promising waterless stimulation technique in the development of unconventional resources.While numerous studies have delved into the inducedfracture mechanism of SC-CO_(2),the small scale of rock samples and synthetic materials used in many studies have limited a comprehensive understanding of fracture propagation in unconventional formations.In this study,cubic tight sandstone samples with dimensions of 300 mm were employed to conduct SC-CO_(2)fractu ring experiments under true-triaxial stre ss conditions.The spatial morphology and quantitative attributes of fracture induced by water and SC-CO_(2)fracturing were compared,while the impact of in-situ stress on fracture propagation was also investigated.The results indicate that the SCCO_(2)fracturing takes approximately ten times longer than water fracturing.Furthermore,under identical stress condition,the breakdown pressure(BP)for SC-CO_(2)fracturing is nearly 25%lower than that for water fracturing.A quantitative analysis of fracture morphology reveals that water fracturing typically produces relatively simple fracture pattern,with the primary fracture distribution predominantly controlled by bedding planes.In contrast,SC-CO_(2)fracturing results in a more complex fracture morphology.As the differential of horizontal principal stress increases,the BP for SC-CO_(2)fractured rock exhibits a downward trend,and the induced fracture morphology becomes more simplified.Moreover,the presence of abnormal in-situ stress leads to a further increase in the BP for SC-CO_(2)fracturing,simultaneously enhancing the development of a more conductive fracture network.These findings provide critical insights into the efficiency and behavior of SC-CO_(2)fracturing in comparison to traditional water-based fracturing,offering valuable implication for its potential applications in unconventional reservoirs. 展开更多
关键词 Supercritical CO_(2) True-triaxial fracturing Tight sandstone Fracture propagation quantitative analysis
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Attention Eraser and Quantitative Measures for Automated Bone Age Assessment
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作者 Liuqiang Shu Lei Yu 《Computers, Materials & Continua》 SCIE EI 2025年第1期627-644,共18页
Bone age assessment(BAA)aims to determine whether a child’s growth and development are normal concerning their chronological age.To predict bone age more accurately based on radiographs,and for the left-hand X-ray im... Bone age assessment(BAA)aims to determine whether a child’s growth and development are normal concerning their chronological age.To predict bone age more accurately based on radiographs,and for the left-hand X-ray images of different races model can have better adaptability,we propose a neural network in parallel with the quantitative features from the left-hand bone measurements for BAA.In this study,a lightweight feature extractor(LFE)is designed to obtain the featuremaps fromradiographs,and amodule called attention erasermodule(AEM)is proposed to capture the fine-grained features.Meanwhile,the dimensional information of the metacarpal parts in the radiographs is measured to enhance the model’s generalization capability across images fromdifferent races.Ourmodel is trained and validated on the RSNA,RHPE,and digital hand atlas datasets,which include images from various racial groups.The model achieves a mean absolute error(MAE)of 4.42 months on the RSNA dataset and 15.98 months on the RHPE dataset.Compared to ResNet50,InceptionV3,and several state-of-the-art methods,our proposed method shows statistically significant improvements(p<0.05),with a reduction in MAE by 0.2±0.02 years across different racial datasets.Furthermore,t-tests on the features also confirm the statistical significance of our approach(p<0.05). 展开更多
关键词 Bone age assessment attention eraser quantitative feature metacarpal bones
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Quantitative detection of trace nanoplastics (down to 50 nm) via surface-enhanced Raman scattering based on the multiplex-feature coffee ring 被引量:1
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作者 Xinao Lin Fengcai Lei +5 位作者 Xiu Liang Yang Jiao Xiaofei Zhao Zhen Li Chao Zhang Jing Yu 《Opto-Electronic Advances》 2025年第6期27-39,共13页
Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate ... Quantitative detection of trace small-sized nanoplastics(<100 nm)remains a significant challenge in surface-enhanced Raman scattering(SERS).To tackle this issue,we developed a hydrophobic CuO@Ag nanowire substrate and introduced a multiplex-feature analysis strategy based on the coffee ring effect.This substrate not only offers high Raman enhancement but also exhibits a high probability of detection(POD),enabling rapid and accurate identification of 50 nm polystyrene nanoplastics over a broad concentration range(1–10−10 wt%).Importantly,experimental results reveal a strong correlation between the coffee ring formation and the concentration of nanoplastic dispersion.By incorporating Raman signal intensity,coffee ring diameter,and POD as combined features,we established a machine learning-based mapping between nanoplastic concentration and coffee ring characteristics,allowing precise predictions of dispersion concentration.The mean squared error of these predictions is remarkably low,ranging from 0.21 to 0.54,representing a 19 fold improvement in accuracy compared to traditional linear regression-based methods.This strategy effectively integrates SERS with wettability modification techniques,ensuring high sensitivity and fingerprinting capabilities,while addressing the limitations of Raman signal intensity in accurately reflecting concentration changes at ultra-low levels,providing a new idea for precise SERS measurements of nanoplastics. 展开更多
关键词 quantitative detection of trace nanoplastics surface-enhanced Raman scattering coffee ring multiplexfeature analysis machine learning
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Science Fiction in Latin America,Interdisciplinary Paradigm,and the Regional Studies for Latin America:An Interview with Joanna Page
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作者 Jiang Yuqin Joanna Page 《外国文学研究》 北大核心 2025年第2期1-12,共12页
Joanna Page is Director of CRASSH and Professor of Latin American Studies at the University of Cambridge.Her research interests are generally connected to the relationship between science and culture in Latin America.... Joanna Page is Director of CRASSH and Professor of Latin American Studies at the University of Cambridge.Her research interests are generally connected to the relationship between science and culture in Latin America.She has also worked on questions of memory,modernity,capitalism,posthumanism,new materialism,decoloniality,ecology,and environmental thought.This interview covers three main aspects:the characteristics of science fiction texts in Latin America,the interdisciplinary research models at the intersection of science,literature,and art,and Latin America as a field of regional studies.Professor Page starts with Argentine science fiction novels and expands the discussion to include graphic novels in Latin America,outlining the panorama of science fiction and its indigenous features.The conversation delves into the literary and technological relationships within Latin American science fiction texts.Building upon this foundation,this interview explores the interdisciplinary research paradigms concerning the relationship between science and culture,aiming to contribute to regional studies by exploring new pathways for interdisciplinary,cross-regional,and trans-media research. 展开更多
关键词 science fiction in Latin America interdisciplinary studies regional studies
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Quantitative Strengthening Evaluation of Mg-Zn-Y Alloys Containing Icosahedral Quasi-Crystalline Phase
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作者 Wang Yingnan Meng Xiaokai Guo Junhong 《稀有金属材料与工程》 北大核心 2025年第3期612-617,共6页
Mg-4.8Zn-0.8Y,Mg-18Zn-3Y,Mg-15Zn-5Y,Mg-30Zn-5Y and Mg-42Zn-7Y(wt%)alloys containing icosahedral quasicrystalline phases were prepared using the ordinary solidification method.The impact of Mg matrix porosity on the te... Mg-4.8Zn-0.8Y,Mg-18Zn-3Y,Mg-15Zn-5Y,Mg-30Zn-5Y and Mg-42Zn-7Y(wt%)alloys containing icosahedral quasicrystalline phases were prepared using the ordinary solidification method.The impact of Mg matrix porosity on the tensile strength and hardness of the alloys was studied.The porosity of the Mg matrix was quantitatively assessed using scanning electron microscope and Image-Pro Plus 6.0 software.Tensile tests were conducted at room temperature.Results show that the maximum tensile strength of the alloy is 175.56 MPa,with a corresponding Mg matrix porosity of 76.74%.Through fitting analysis,it is determined that the maximum tensile strength is achieved when the porosity of the Mg matrix is 64.87%.The microhardness test results indicate a gradual decrease in alloy hardness with increasing the porosity of Mg matrix.This study provides an effective quantitative analysis method for enhancing the mechanical properties of magnesium alloys. 展开更多
关键词 Mg-Zn-Y alloy Mg matrix porosity mechanical properties quantitative analysis
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Evaluation of the shear stability of aerobic granular sludge from a pilot-scale membrane bioreactor:Establishment of a quantitative method
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作者 Biao Yang Bingduo Wang +7 位作者 Liying Bin Weirui Chen Xinyi Chen Ping Li Shanglong Wen Shaosong Huang Zhiqi Zhang Bing Tang 《Journal of Environmental Sciences》 2025年第2期579-590,共12页
This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for... This work established a quantitative method to access the shear stability of aerobic granular sludge(AGS)and validated its feasibility by using the mature AGS from a pilot-scale(50 tons/day)membrane bioreactor(MBR)for treating real municipal wastewater.The results showed that the changing rate( S)of the peak area(S)of granule size distribution(GSD)exhibited an exponential relationship(R^(2)≥0.76)with the shear time(y=a−b·c^(x)),which was a suitable indicative index to reflect the shear stability of different AGS samples.The limiting granule size(LGS)was defined and proposed to characterize the equilibrium size for AGS after being sheared for a period of time,whose value in terms of Dv50 showed high correlation(R^(2)=0.92)with the parameter a.The free Ca^(2+)(28.44-34.21 mg/L)in the influent specifically interacted with polysaccharides(PS)in the granule’s extracellular polymeric substance(EPS)as a nucleation site,thereby inducing the formation of Ca precipitation to enhance its Young’s modulus,while Ca^(2+) primarily interacted with PS in soluble metabolic product(SMP)during the initial granulation process.Furthermore,the Young’s modulus significantly affected the parameter a related to shear stability(R^(2)=0.99).Since the parameter a was more closely related(R^(2)=1.00)to S than that of the parameter b or c,the excellent correlation(R^(2)=0.99)between the parameter a and the wet density further verified the feasibility of this method. 展开更多
关键词 Shear stability quantitative evaluation Aerobic granular sludge Membrane bioreactor Pilot-scale study Municipal wastewater
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Quantitative measure and visualization for local shock strength in two-dimensional flow
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作者 Jiashuo Li Aiming Shi Earl H.Dowell 《Acta Mechanica Sinica》 2025年第5期79-92,共14页
The concept of local shock strength and a quantitative measure index str of local shock strength are proposed,derived from the oblique shock relation and the monotonic relationship between total pressure loss ratio an... The concept of local shock strength and a quantitative measure index str of local shock strength are proposed,derived from the oblique shock relation and the monotonic relationship between total pressure loss ratio and normal Mach number.Utilizing the high density gradient characteristic of shock waves and the oblique shock relation,a post-processing algorithm for two-dimensional flow field data is developed.The objective of the post-processing algorithm is to obtain specific shock wave location coordinates and calculate the corresponding str from flow filed data under the calibration of the oblique shock relation.Valida-tion of this post-processing algorithm is conducted using a standard model example that can be solved analytically.Combining the concept of local shock strength with the post-processing algorithm,a local shock strength quantitative mapping approach is established for the first time.This approach enables a quantitative measure and visualization of local shock strength at distinct locations,represented by color mapping on the shock structures.The approach can be applied to post-processing numerical sim-ulation data of two-dimensional flows.Applications to the intersection of two left-running oblique shock waves(straight shock waves),the bow shock in front of a cylinder(curved shock wave),and Mach reflection(mixed straight and curved shock waves)demonstrate the accuracy,and effectiveness of the mapping approach in investigating diverse shock wave phenomena.The quan-titative mapping approach of str may be a valuable tool in the design of supersonic/hypersonic vehicles and the exploration of shock wave evolution. 展开更多
关键词 Shock wave Local shock strength quantitative measure index Post-processing algorithm quantitative mapping
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New Directions in the Interdisciplinary Studies of Literature and Economics: An Interview with Paul Crosthwaite
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作者 Deng Yingling Paul Crosthwaite 《外国文学研究》 北大核心 2025年第1期1-10,共10页
Professor Paul Crosthwaite,from the School of Literature,Languages,and Cultures at the University of Edinburgh,is a prominent scholar in the interdisciplinary field of literature and economics.He is a co-editor of the... Professor Paul Crosthwaite,from the School of Literature,Languages,and Cultures at the University of Edinburgh,is a prominent scholar in the interdisciplinary field of literature and economics.He is a co-editor of the Palgrave Studies in Literature,Culture,and Economics series and The Cambridge Companion to Literature and Economics(2022).In recent years,he has significantly influenced the intersection of literature and economics,advocating particularly for a shift towards the Economic Humanities.This interview covers:1.The definition and theoretical origin of the Economic Humanities;2.The internal heterogeneity and critical limitations of the New Economic Criticism,and the theoretical advantages and potential development of the Economic Humanities;3.What research paradigms do Environmental Humanities,Medical Humanities,and Digital Humanities provide for the Economic Humanities;4.How literary researchers can work at the interface of the Economic Humanities research.As a novel interdisciplinary interface between literature and economics,Professor Paul Crosthwaite’s concept of the Economic Humanities not only pioneers methodological tools for interdisciplinary studies of literature and economics but also underscores the interpretative potential and disciplinary benefits of literary viewpoints on economics.This underscores the vital role of literature in human knowledge,meriting attention from the literary research academia. 展开更多
关键词 the Economic Humanities interdisciplinary studies of Literature and Economics new directions Paul Crosthwaite
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Trajectory Modelling:A Novel Approach to Dig Value of Longitudinal Cohort Studies
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作者 Siyan Zhan 《Biomedical and Environmental Sciences》 2025年第6期651-652,共2页
Cohort studies are important epidemiological methods to investigate associations between environmental factors,individual characteristics,and disease or other health outcomes.As a paradigm of cohort studies,the Framin... Cohort studies are important epidemiological methods to investigate associations between environmental factors,individual characteristics,and disease or other health outcomes.As a paradigm of cohort studies,the Framingham Heart Study(FHS)is the longest-running cardiovascular epidemiological study,starting in 1948. 展开更多
关键词 epidemiological methods NOVEL DIG cohort studiesthe cohort studies framingham heart study fhs APPROACH TRAJECTORY
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Cryptocurrency Volatility and Its Impact on Emerging Markets: Quantitative Analysis
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作者 Xinyang Kray Wang 《Economics World》 2025年第2期106-112,共7页
Cryptocurrency,a booming decentralised asset designed based on the blockchain architecture,is particularly important to the market at the present time by studying the volatility risk of cryptocurrencies.In this paper,... Cryptocurrency,a booming decentralised asset designed based on the blockchain architecture,is particularly important to the market at the present time by studying the volatility risk of cryptocurrencies.In this paper,we empirically analyse the volatility risk of cryptocurrencies through quantitative analysis models,comprehensively using the Markov state transition GARCH model with skewed distribution(Skew-MSGARCH)and the autoregressive conditional volatility density ARJI model introducing the Poisson jump factor,and selecting the earliest developed and the most mature currency price volatility daily return series,to deeply explore the volatility risk of digital cryptocurrencies.risk.Finally,it can be seen through in-depth analyses that the expectation factor and information inducement are the main reasons leading to the exacerbation of the volatility risk of digital cryptocurrencies.It is recommended that this situation be optimised and improved in terms of the value function of digital cryptocurrencies themselves and the implementation of systematic risk management and regulatory innovation.As an important component of the digital economy,blockchain technology can effectively regulate and improve the volatility of digital cryptocurrencies under macroeconomic policies,thereby maintaining the security and stability of emerging financial markets. 展开更多
关键词 cryptocurrency VOLATILITY emerging markets quantitative analysis
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Application of artificial intelligence to quantitative structure-retention relationship calculations in chromatography
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作者 Jingru Xie Si Chen +1 位作者 Liang Zhao Xin Dong 《Journal of Pharmaceutical Analysis》 2025年第1期4-18,共15页
Quantitative structure-retention relationship(QSRR)is an important tool in chromatography.QSRR examines the correlation between molecular structures and their retention behaviors during chromatographic separation.This... Quantitative structure-retention relationship(QSRR)is an important tool in chromatography.QSRR examines the correlation between molecular structures and their retention behaviors during chromatographic separation.This approach involves developing models for predicting the retention time(RT)of analytes,thereby accelerating method development and facilitating compound identification.In addition,QSRR can be used to study compound retention mechanisms and support drug screening efforts.This review provides a comprehensive analysis of QSRR workflows and applications,with a special focus on the role of artificial intelligence-an area not thoroughly explored in previous reviews.Moreover,we discuss current limitations in RT prediction and propose promising solutions.Overall,this review offers a fresh perspective on future QSRR research,encouraging the development of innovative strategies that enable the diverse applications of QSRR models in chromatographic analysis. 展开更多
关键词 quantitative structure-retention RELATIONSHIP CHROMATOGRAPHY ACCURACY Machine learning
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High-precision quantitative analysis of 3-nitro-1,2,4-triazol-5-one(NTO)concentration based on ATR-FTIR spectroscopy and machine learning
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作者 Zhe Zhang Zhuowei Sun +4 位作者 Haoming Zou Xijuan Lv Ziyang Guo Shuai Zhao Qinghai Shu 《Defence Technology(防务技术)》 2025年第10期131-141,共11页
3-Nitro-1,2,4-triazol-5-one(NTO)is a typical high-energy,low-sensitivity explosive,and accurate concentration monitoring is critical for crystallization process control.In this study,a high-precision quantitative anal... 3-Nitro-1,2,4-triazol-5-one(NTO)is a typical high-energy,low-sensitivity explosive,and accurate concentration monitoring is critical for crystallization process control.In this study,a high-precision quantitative analytical model for NTO concentration in ethanol solutions was developed by integrating real-time ATR-FTIR spectroscopy with chemometric and machine learning techniques.Dynamic spectral data were obtained by designing multi-concentration gradient heating-cooling cycle experiments,abnormal samples were eliminated using the isolation forest algorithm,and the effects of various preprocessing methods on model performance were systematically evaluated.The results show that partial least squares regression(PLSR)exhibits superior generalization ability compared to other models.Vibrational bands corresponding to C=O and–NO_(2)were identified as key predictors for concentration estimation.This work provides an efficient and reliable solution for real-time concentration monitoring during NTO crystallization and holds significant potential for process analytical applications in energetic material manufacturing. 展开更多
关键词 ATR-FTIR spectroscopy Machine learning quantitative analysis
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Quantitative Analysis of the Policy of Centralized Drug Procurement Based on PMC Index Model
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作者 Duan Xiaoxiang Wang Shuling 《Asian Journal of Social Pharmacy》 2025年第3期222-235,共14页
Objective To quantitatively analyze the policy of centralized drug procurement centralized drug procurement in order to provide reference for the subsequent policy formulation and improvement.Methods Text mining metho... Objective To quantitatively analyze the policy of centralized drug procurement centralized drug procurement in order to provide reference for the subsequent policy formulation and improvement.Methods Text mining method was used to process 15 centralized drugs procurement policies issued at the national level during 2015-2022,and a PMC index evaluation model of centralized drug procurement policies was established.Then,15 centralized drug procurement policies were quantitatively analyzed from the overall and comparative perspective through an evaluation model.Results and Conclusion The average PMC index of 15 centralized drug procurement policies was 6.95,which was acceptable on the whole.Among them,eight were excellent and seven were acceptable.As to the first-order variables,the centralized drugs procurement policy still lacks incentives and constraints.The comparative results show that there are differences in the content and structure of policies,but they are strongly related to each other.Chinese centralized drug procurement policy has been basically formed,which is closely related to medical insurance and medical policies.However,it is still necessary to pay attention to the structure of the policy to ensure the elaboration of the policy content. 展开更多
关键词 centralized drug procurement PMC index POLICY quantitative analysis
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Quantitative Effects of Velocity and Residual Pressure Level on Aerodynamic Noise of Ultra-High-Speed Maglev Trains
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作者 Lanxi Zhang Yuming Peng Yudong Wu 《Fluid Dynamics & Materials Processing》 2025年第1期205-220,共16页
The challenge of aerodynamic noise is a key obstacle in the advancement of low-pressure tube ultra-high-speed maglev transportation,demanding urgent resolution.This study utilizes a broadband noise source model to per... The challenge of aerodynamic noise is a key obstacle in the advancement of low-pressure tube ultra-high-speed maglev transportation,demanding urgent resolution.This study utilizes a broadband noise source model to perform a quantitative analysis of the aerodynamic noise produced by ultra-high-speed maglev trains operating in low-pressure environments.Initially,an external flow field calculation model for the ultra-high-speed maglev train is presented.Subsequently,numerical simulations based on the broadband noise source model are used to examine the noise characteristics.The impact of the train speed and pressure level on noise generation is investigated accordingly.Subsequently,a correlation formula is derived.The results reveal that the amplitude of sound source changes in the streamlined region of the head and tail cars of the train is large,and the amplitude of changes for the middle car is smaller.The noise source strength increases with speed,with a quadrupole noise source becoming dominant when the train speed exceeds 600 km/h.At a speed of 1000 km/h,the noise source intensity from the streamlined area at the rear of the train overcomes that at the front.Furthermore,the noise source decreases as the pressure level in the tube decreases.When the pressure level drops to 0.01 atm,the quadrupole noise source intensity of a train running at 600 km/h significantly weakens and falls below that of the dipole noise source. 展开更多
关键词 Low-pressure tube aerodynamic noise train speed quantitative analysis
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Quantitative Study of Multiple Components in Tetracera asiatica Based on High-Performance Liquid Chromatography
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作者 Fangfang DA Yufeng CHEN +4 位作者 Ziwan YUAN Ying LIU Yaoting MENG Kequn HE Yanmin XIE 《Asian Agricultural Research》 2025年第10期28-31,44,共5页
[Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Method... [Objectives]To establish an HPLC method for the quantitative determination of multiple phenolic acid components in Tetracera asiatica medicinal material,providing a basis for establishing its quality standards.[Methods]An Inertsil ODS-C 18 column(250 mm×4.6 mm,5μm)was used.The mobile phase consisted of acetonitrile-0.2% phosphoric acid solution(10:90).The flow rate was 1.0 mL/min.The detection wavelength was 274 nm.The column temperature was 25℃.The injection volume was 10μL.The content of three components,gallic acid,protocatechuic acid,and protocatechualdehyde,was determined in 13 batches of T.asiatica.[Results]Gallic acid showed good linearity within the range of 0.020-6.400μg/mL,protocatechuic acid within 0.201-6.432μg/mL,and protocatechualdehyde within 0.202-6.464μg/mL(r>0.9990).The average recovery rates ranged from 98.61%to 101.17%,with RSD s between 1.21%and 2.69%.[Conclusions]The quantitative determination method established in this study is simple and feasible,and can provide a basis for the quality evaluation of T.asiatica. 展开更多
关键词 Tetracera asiatica HIGH-PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC) COMPONENTS quantitative determination
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Ultra-simplified design and quantitative analysis for the optical system of compact laser-induced breakdown spectroscopy
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作者 Jiujiang YAN Ke LIU +3 位作者 Jinxiu MA Yang LI Kailong LI Hongwei WEI 《Plasma Science and Technology》 2025年第3期87-93,共7页
Optimization and simplification of optical systems represent a milestone in advancing the development of handheld and portable laser-induced breakdown spectroscopy(LIBS)systems towards smaller,more integrated forms.Th... Optimization and simplification of optical systems represent a milestone in advancing the development of handheld and portable laser-induced breakdown spectroscopy(LIBS)systems towards smaller,more integrated forms.This research,for the first time,conducted a comprehensive optimization design and comparative analysis of three compact LIBS system optical paths:the paraxial optical path(OP),the off-axis OP,and the reflective OP.The differences in spectral intensity and stability among these paths were revealed,providing a scientific basis for selecting the optimal OP for LIBS systems.The research found that the paraxial OP excels in spectral performance and quantitative analysis accuracy,making it the preferred choice for compact LIBS systems.Specifically,the paraxial OP significantly enhances spectral intensity,achieving a 6 times improvement over the off-axis OP and an even more remarkable 150 times increase compared to the reflective OP,greatly enhancing detection sensitivity.Additionally,the relative standard deviation,spectral stability index,maintains a consistently low level,ranging from 10.9%to 13.4%,significantly outperforming the other two OPs and ensuring the reliability of analytical results.In the field of quantitative analysis,the paraxial OP also demonstrates higher accuracy,precision,and sensitivity,comparing to other OPs.The quantitative analysis models for Si,Cu,and Ti elements exhibit excellent fitting,providing users with high-quality quantitative analysis results that are of great significance for applications in material science,environmental monitoring,industrial inspection,and other fields.In summary,this study not only confirms the enormous application potential of the paraxial OP in compact LIBS systems but also provides valuable practical experience and theoretical support for the miniaturization and integration of LIBS systems.Looking ahead,with continuous technological advancements,the design of the paraxial OP is expected to further propel the widespread adoption of LIBS technology in portable,on-site detection applications. 展开更多
关键词 compact LIBS optical path design spectral stability quantitative analysis
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A quantitative evaluation method of laser treatment efficacy for pigmentary dermatosis based on image segmentation technology
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作者 Haopu Jian Qi Chen +3 位作者 Youjun Yu Cheng Wang Peiru Wang Xiuli Wang 《Journal of Innovative Optical Health Sciences》 2025年第4期89-99,共11页
A growing number of skin laser treatments have rapidly evolved and increased their role in the field of dermatology,laser treatment is considered to be used for a variety of pigmentary dermatosis as well as aesthetic ... A growing number of skin laser treatments have rapidly evolved and increased their role in the field of dermatology,laser treatment is considered to be used for a variety of pigmentary dermatosis as well as aesthetic problems.The standardized assessment of laser treatment efficacy is crucial for the interpretation and comparison of studies related to laser treatment of skin disorders.In this study,we propose an evaluation method to quantitatively assess laser treatment efficacy based on the image segmentation technology.A tattoo model of Sprague Dawley(SD)rats was established and treated by picosecond laser treatments at varying energy levels.Images of the tattoo models were captured before and after laser treatment,and feature extraction was conducted to quantify the tattooed area and pigment gradation.Subsequently,the clearance rate,which has been a standardized parameter,was calculated.The results indicate that the clearance rates obtained through this quantitative algorithm are comparable and exhibit smaller standard deviations compared with scale scores(4.59%versus 7.93%in the low-energy group,4.01%versus 9.05%in the medium-energy group,and 4.29%versus 10.23%in the high-energy group).This underscores the greater accuracy,objectivity,and reproducibility in assessing treatment responses.The quantitative evaluation of pigment removal holds promise for facilitating faster and more robust assessments in research and development.Additionally,it may enable the optimization of treatments tailored to individual patients,thereby contributing to more effective and personalized dermatological care. 展开更多
关键词 Pigmentary dermatosis picosecond laser image segmentation quantitative evaluation
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