Recently, the domestic real estate environment is good, the rapid development of China's real estate industry for real estate transactions, there is a positive direction, the sales increased year by year. Real est...Recently, the domestic real estate environment is good, the rapid development of China's real estate industry for real estate transactions, there is a positive direction, the sales increased year by year. Real estate sales price is in the housing area multiplied by the real estate unit sales price, so the accuracy of the real estate is directly related to the interests of property owners and developers, and in order to comprehensive management of housing area chart, the housing authority must use housing area chart to manage the property, and to help the owner to maintain its interests, and strictly control the housing area chart, in order to avoid interference, reduce errors. This paper mainly expounds the two meanings of the real estate surface, and analyzes the common problems in the mapping of the real estate surface, so that the peer in the mapping of the real estate surface reference.展开更多
Access to security and safe food is a basic human necessity and essential for a sustainable world. To perform hi-end rood safety analysis and risk assessment with state of the art technologies is of utmost importance ...Access to security and safe food is a basic human necessity and essential for a sustainable world. To perform hi-end rood safety analysis and risk assessment with state of the art technologies is of utmost importance thereof. With applications as exemplified by microfiuidic immunoassay, aptasensor, direct analysis in real time, high resolution mass spectrometry, benchmark dose and chemical specific adjustment factor, this review presents frontier food safety analysis and risk assessment technologies, from which both food quality and public health will benefit undoubtedly in a foreseeable future.展开更多
Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric rout...Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carded out with three main objectives： （i） to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, （ii） to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and （iii） to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carded out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.展开更多
Objective:Neoadjuvant chemotherapy(NAC)is currently used in both early stage and locally advanced breast cancers.The survival benefits of standard vs.non-standard NAC cycles are still unclear.This study aimed to inves...Objective:Neoadjuvant chemotherapy(NAC)is currently used in both early stage and locally advanced breast cancers.The survival benefits of standard vs.non-standard NAC cycles are still unclear.This study aimed to investigate the relationship between NAC cycles and survival based on real world data.Methods:We identified patients diagnosed with invasive primary breast cancers who underwent NAC followed by surgery.Patients who received at least 4 NAC cycles were defined as having received standard cycles,while patients who received less than 4 NAC cycles were defined as having received non-standard cycles.Kaplan-Meier curves and Cox proportional hazard models were used to estimate the disease-free survival(DFS)and overall survival(OS).Results:Of the 1,024 included patients,700 patients received standard NAC cycles and 324 patients received non-standard NAC cycles.The DFS estimates were 87.1%and 81.0%(P=0.007)and the OS estimates were 90.0%and 82.6%(P=0.001)in the standard and non-standard groups,respectively.Using multivariate analyses,patients treated with standard NAC cycles showed significant survival benefits in both DFS[hazard ratio(HR):0.62,95%confidence interval(CI):0.44–0.88]and OS(HR:0.54,95%CI:0.37–0.79).Using stratified analyses,standard NAC cycles were associated with improved DFS(HR:0.59,95%CI:0.36–0.96)and OS(HR:0.49,95%CI:0.28–0.86)in the HER2 positive group.Similar DFS(HR:0.50,95%CI:0.25–0.98)and OS(HR:0.45,95%CI:0.22–0.91)benefits were shown for the triple negative group.Conclusions:Standard NAC cycles were associated with a significant survival benefit,especially in patients with HER2 positive or triple negative breast cancer.展开更多
We propose a novel stochastic modeling framework for coal production and logistics using option pricing theory.The problem of valuing the inherent real optionality a coal producer has when mining and processing therma...We propose a novel stochastic modeling framework for coal production and logistics using option pricing theory.The problem of valuing the inherent real optionality a coal producer has when mining and processing thermal coal is modelled as pricing spread options of three assets under the stochastic volatility model.We derive a three-dimensional Fast Fourier Transform(“FFT”)lower bound approximation to value the inherent real optionality and for robustness check,we compare the semi-analytical pricing accuracy with the Monte Carlo simulation.Model parameters are estimated from the historical monthly data,and stochastic volatility parameters are obtained by matching the Kurtosis of the low-ash diff data to the Kurtosis of the stochastic volatility process which is assumed to follow Cox–Ingersoll–Ross(“CIR”)model.展开更多
In the food production sector,quickly identifying potential hazards is crucial due to the resilience of many pathogens,which could lead to wasted production results and,more severely,epidemic outbreaks.E.coli monitori...In the food production sector,quickly identifying potential hazards is crucial due to the resilience of many pathogens,which could lead to wasted production results and,more severely,epidemic outbreaks.E.coli monitoring is essential;however,traditional quality control methods in fish farming are often slow and intrusive,thus promoting an increase in fish stress and mortality rates.This paper presents an alternative method by utilizing a prototype inspired by polarized optical microscopy(POM),constructed with a Raspberry Pi microprocessor to assess pixel patterns and calculate analyte levels.展开更多
SUMMARIES OF TOP NEWS STORIES CHINA Safeguarding Gaokao Fairness This year’s gaokao,China’s national college entrance exam,began on 7 June,with a record 13.35 million students taking part.As one of the country’s mo...SUMMARIES OF TOP NEWS STORIES CHINA Safeguarding Gaokao Fairness This year’s gaokao,China’s national college entrance exam,began on 7 June,with a record 13.35 million students taking part.As one of the country’s most important annual events,the 2025 gaokao has seen extensive nation-wide efforts to ensure fairness,safety,and support for all candidates.Authorities have implemented a range of security and logistical measures to safeguard exam integrity.AI-powered monitoring systems have been rolled out in provinces like Jiangxi,Hubei,and Guangdong,enabling real-time behaviour analysis and early warnings without human intervention.These tools reduce pressure on staff and strengthen fairness.展开更多
Although a great deal of research has been dedicated to the synthesis of spiral bevel gears, little related to reverse engineering can be found. An approach is proposed to reverse the machine-tool settings of the pini...Although a great deal of research has been dedicated to the synthesis of spiral bevel gears, little related to reverse engineering can be found. An approach is proposed to reverse the machine-tool settings of the pinion of a spiral bevel gear drive on the basis of the blank and tooth surface data obtained by a coordinate measuring machine(CMM). Real tooth contact analysis(RTCA) is performed to preliminary ascertain the contact pattern, the motion curve, as well as the position of the mean contact point. And then the tangent to the contact path and the motion curve are interpolated in the sense of the least square method to extract the initial values of the bias angle and the higher order coefficients(HOC) in modified roll motion. A trial tooth surface is generated by machine-tool settings derived from the local synthesis relating to the initial meshing performances and modified roll motion. An optimization objective is formed which equals the tooth surface deviation between the real tooth surface and the trial tooth surface. The design variables are the parameters describing the meshing performances at the mean contact point in addition to the HOC. When the objective is optimized within an arbitrarily given convergence tolerance, the machine-tool settings together with the HOC are obtained. The proposed approach is verified by a spiral bevel pinion used in the accessory gear box of an aviation engine. The trial tooth surfaces approach to the real tooth surface on the whole in the example. The results show that the convergent tooth surface deviation for the concave side on the average is less than 0.5 μm, and is less than 1.3 μm for the convex side. The biggest tooth surface deviation is 6.7 μm which is located at the corner of the grid on the convex side. Those nodes with relative bigger tooth surface deviations are all located at the boundary of the grid. An approach is proposed to figure out the machine-tool settings of a spiral bevel pinion by way of reverse engineering without having known the theoretical tooth surfaces and the corresponding machine-tool settings.展开更多
Ambient mass spectrometry facilitates surface detection under ambient conditions and has quickly found its applications in various areas.However,the sensitivity of AMS methods is usually not as good as that of encapsu...Ambient mass spectrometry facilitates surface detection under ambient conditions and has quickly found its applications in various areas.However,the sensitivity of AMS methods is usually not as good as that of encapsulated ion sources due to less efficient ion transmission.In this work,a briefly machined external ion funnel(threepole electrostatic lens)was adopted and installed between direct analysis in real time and the mass spectrometer inlet to increase detection sensitivity.Software investigation with SIMION version 8.0 was employed to calculate electric fields and to simulate the trajectories of charged particles in the electric field.Both the geometrical parameters of the ion funnel and the electric parameters were studied to obtain the optimal ion focusing results,which demonstrated the ion funnel equipment would greatly improve the ion transmission efficiency.The equipment showed good prospect in direct analysis in real time-mass spectrometry analysis in the future.展开更多
An environmentally friendly,low power consuming,sensitive and compact mercury analyzer was developed for the determination of mercury in water samples by integrating a thin film dielectric barrier discharge induced co...An environmentally friendly,low power consuming,sensitive and compact mercury analyzer was developed for the determination of mercury in water samples by integrating a thin film dielectric barrier discharge induced cold vapor reactor and a dielectric barrier discharge optical emission spectrometer into a small polymethyl methacrylate plate（10.5 cm length×8.0 cm width×1.2 cm height）.Mercury cold vapor was generated when standard or sample solutions with or without formic acid were introduced to the reactor to form thin film liquid and exposed to microplasma irradiation and subsequently separated from the liquid phase for transport to the microplasma and detection of its atomic emission.Limits of detection of 0.20 μg L^-1 and 2.6 μg L^-1 were obtained for the proposed system using or not using formic acid,respectively.Compared to the conventional microplasma optical emission spectrometry used for mercury analysis,this system not only retains the good limit of detection amenable to the determination of mercury in real samples,but also reduces power consumption,eliminates the generation of hydrogen and avoids the use of toxic or unstable reductant.Method validation was demonstrated by analysis of a certified reference material of water sample and three real water samples with good spike recoveries（88-102%）.展开更多
A method for rapid identification and quantification of phthalate plasticizers in beverages was developed.A number of 15 phthalate plasticizers which covered all the phthalates concerned in the US Consumer Product Saf...A method for rapid identification and quantification of phthalate plasticizers in beverages was developed.A number of 15 phthalate plasticizers which covered all the phthalates concerned in the US Consumer Product Safety Improvement Act(CPSIA),European Union legislations and Chinese national standards(GB)were analyzed.By a combined solid-phase micro-extraction(SPME)and direct analysis in real time mass spectrometry(DART-MS)approach,phthalates at sub-ng•mL^(−1)levels can be qualitatively and quantitatively analyzed in a short time.The use of ultrahigh-resolving power and the accurate mass measurement capacity naturally provided by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)minimizes the matrix interferences and thus enables the evaluation of phthalates in a complex matrix without extensive sample handlings or preparations.The limits of quantification(LOQs)were estimated to be at 0.3-5.0 ng•mL^(−1),lower than the Maximum Residue Limit(MRL)regulated by the European Union legislations(2007/19/EC)in foods,beverages,food packaging and toys(0.3-30 ng•mL^(−1)).This rapid and easy-to-use SPME-DART-FT-ICR-MS method provided a relatively high-throughput and powerful analytical approach for quick testing and screening phthalates in beverages and water samples to ensure food safety.展开更多
We aimed to establish for the rapid detection of morphine,O6‑monoacetylmorphine,heroin,codeine,cocaine,methamphetamine,ketamine,methadone,and dolantin in human blood and urine by direct analysis in real‑time coupled w...We aimed to establish for the rapid detection of morphine,O6‑monoacetylmorphine,heroin,codeine,cocaine,methamphetamine,ketamine,methadone,and dolantin in human blood and urine by direct analysis in real‑time coupled with tandem mass spectrometry(DART‑MS/MS).These samples were extracted by acetonitrile‑methanol(V/V=4:1),using DART 12 Dip‑it automatic sampling system.They were injected at 400℃,and analyzed by positive ion and multiple reaction monitoring mode.The detection limits of morphine,O6‑Monoacetylmorphine,heroin,codeine,cocaine,methamphetamine,ketamine,methadone,and dolantin were 100,50,50,100,20,20,10,1,and 0.01 ng/mL,respectively.The practical cases contained methamphetamine,codeine,cocaine,and O6‑monoacetylmorphine were detected accurately and rapidly.The method has the advantages of high sensitivity and good accuracy.The sample processing is simple and can be analyzed in a short time.This method is suitable for the analysis of morphine,O6‑monoacetylmorphine,heroin,codeine,cocaine,methamphetamine,ketamine,methadone,and dolantin in some practical cases.展开更多
This paper,through mass spectrometric(MS)analysis for nitro compound explosives on a direct analysis in a real‑time time‑of‑flight MS,indicates that even on a high‑resolution MS with accurate mass measurement capabili...This paper,through mass spectrometric(MS)analysis for nitro compound explosives on a direct analysis in a real‑time time‑of‑flight MS,indicates that even on a high‑resolution MS with accurate mass measurement capabilities,there is no guarantee to obtain the unique molecular formula of a compound.By calculating spectra accuracy,highly accurate isotope pattern matching can be conducted to significantly improve performance of compound confirmation or identification.展开更多
Direct analysis in real time(DART) possesses the merits of analyzing sample in its native status with minimal or even no sample pretreatment.In this review, we summarized the recent applications of DART in the field o...Direct analysis in real time(DART) possesses the merits of analyzing sample in its native status with minimal or even no sample pretreatment.In this review, we summarized the recent applications of DART in the field of herbal medicine analysis such as compound detection, species identification, metabolites profiling and initial quantification. DART with the characters of hyper-rapid, easy-hyphenated offers a new research tool for herbal medicines to complete the experimental process in a very simple but still reliable way. It is anticipated that more wide and deep applications of DART in herbal medicine analysis, as rapid quantification, high-throughput active compounds screening, rapid species identification, and fast illegal additives screening will be promising and foreseeable in the near future.展开更多
The measurement of amino acid and monoamine neurotransmitters(NTs)in serum plays a central role in the identification and monitoring of clinical panic disorder(PD).However,the strong polarity and chemical heterogeneit...The measurement of amino acid and monoamine neurotransmitters(NTs)in serum plays a central role in the identification and monitoring of clinical panic disorder(PD).However,the strong polarity and chemical heterogeneity of NTs make direct extraction and rapid detection extremely challenging.Herein,we developed a strategy that integrated solid phase extraction based on magnetic Fe_(3)O_(4)coated with polydopamine(Fe_(3)O_(4)@PDA)and direct analysis of mass spectrometry in real time(DART-MS)for quantification of 10 NTs.We systematically investigated the optimal conditions of this strategy to achieve good accuracy and precision.Compared with existing magnetic solid phase extraction methods for NTs detection in biological samples,this strategy could adsorb more targets while having similar adsorption efficiencies,and the total process time was reduced by an average of 69.42%.We rapidly determined the metabolic abnormality of 6 types of NTs in the serum of PD patients and demonstrated their diagnostic accuracy.In addition,an outstanding feature of PD in which tryptophan was more metabolized by the KYN pathway and the 5-hydroxytryptamine pathway was inhibited could be elucidated by this strategy.Our results highlighted the potential ability of Fe_(3)O_(4)@PDA coupled with DART-MS to assist in the clinical diagnosis of PD.展开更多
NiCo2O4 nanosheets with sheaf-like nanostructure morphologies have been synthesized by a facile one-step hydrothermal reaction followed by annealing treatment. Impressively, the NiCo2O4 nanosheets exhibit rapid detect...NiCo2O4 nanosheets with sheaf-like nanostructure morphologies have been synthesized by a facile one-step hydrothermal reaction followed by annealing treatment. Impressively, the NiCo2O4 nanosheets exhibit rapid detection of eugenol. The linear range of detection is from 1-500μM, and the limit of detection is 5.4 μM. The NiCo2O4 modified electrode demonstrated high sensitivity, good repeatability and reproducibility, and long-term stability （7% decrease in response over 30 days）. Based on this work, an electrochemical reaction mechanism for eugenol oxidation was proposed, and in addition, the NiCo2O4 modified electrode was successfully employed for the analysis of eugenol in medicative balm samples. Recovery values for eugenol in medicative balm samples were in the range 98.7%-105.5%.展开更多
In the first part of this paper, we discuss the Holder continuity of the cauchy integral operator for regular functions and the relation between ‖T{f}‖α and ‖f‖α. In the second part of this paper, we introduce t...In the first part of this paper, we discuss the Holder continuity of the cauchy integral operator for regular functions and the relation between ‖T{f}‖α and ‖f‖α. In the second part of this paper, we introduce the modified cauchy integral operator T^- for regular functions. Firstly, we prove that the operator T^- has a unique fixed point by the Banach＇s Contraction Mapping Principle. Secondly, we give the Mann iterative sequence, and then we show the iterative sequence strongly converges to the fixed point of the operator T^-.展开更多
In this paper,the authors study a class of weighted version of probability density estimator.It is shown that the weighted estimator contains some existing estimators of probability density,no matter they are recursiv...In this paper,the authors study a class of weighted version of probability density estimator.It is shown that the weighted estimator contains some existing estimators of probability density,no matter they are recursive or non-recursive.Some statistical results including weak consistency,strong consistency,rate of strong consistency,and asymptotic normality are established under some mild conditions.Moreover,the random weighted estimator is also investigated.Some numerical simulations and a real data analysis are presented to study the numerical performances of the estimators.展开更多
Corporations need to improve business processes in order to enhance velocity and service levels while reducing their processing costs and differentiating themselves in the face of competition. The levitation of import...Corporations need to improve business processes in order to enhance velocity and service levels while reducing their processing costs and differentiating themselves in the face of competition. The levitation of importance beyond support roles has raised IT investment decisions to high priority in chief executive officers＇ agendas. Corporate planning groups as well as lines of business are increasingly applying techniques of IT applications portfolio management in a more systematic fashion to improve decision-making and resource-allocation processes. Recent advances in software engineering and IT service delivery methodologies have achieved the logical separation of business functions from implementation. This separation has made a new breed of innovative IT project possible with a new project risk structure; the adjustment of portfolio management techniques is appropriate. We present an integrated portfolio management model so that the corporation can focus on organic growth through sources at both the department and top management levels. The research gives clear advice as to how top management can seek economic growth by selecting an entrepreneurial strategic posture, implying a strong risk-taking propensity. By integrating a risk-return model and risk-tolerance paradigm to cope with today＇s risk structure, overall capabilities can improve the decision process and the corporation＇s performance as well. The application of the integrated technique to a Japanese manufacturing firm is described.展开更多
文摘Recently, the domestic real estate environment is good, the rapid development of China's real estate industry for real estate transactions, there is a positive direction, the sales increased year by year. Real estate sales price is in the housing area multiplied by the real estate unit sales price, so the accuracy of the real estate is directly related to the interests of property owners and developers, and in order to comprehensive management of housing area chart, the housing authority must use housing area chart to manage the property, and to help the owner to maintain its interests, and strictly control the housing area chart, in order to avoid interference, reduce errors. This paper mainly expounds the two meanings of the real estate surface, and analyzes the common problems in the mapping of the real estate surface, so that the peer in the mapping of the real estate surface reference.
基金financially supported by the Beijing Municipal Science and Technology Project, China (Z131110000613066)the Educational and Teaching Reform Project for Graduate Students, China (G-JG-XJ201408)the Beijing Key Laboratory of Bioprocess, China
文摘Access to security and safe food is a basic human necessity and essential for a sustainable world. To perform hi-end rood safety analysis and risk assessment with state of the art technologies is of utmost importance thereof. With applications as exemplified by microfiuidic immunoassay, aptasensor, direct analysis in real time, high resolution mass spectrometry, benchmark dose and chemical specific adjustment factor, this review presents frontier food safety analysis and risk assessment technologies, from which both food quality and public health will benefit undoubtedly in a foreseeable future.
文摘Extensive investigation has been performed in location-centric or geocast routing protocols for reliable and efficient dissemination of information in Vehicular Adhoc Networks （VANETs）. Various location-centric routing protocols have been suggested in literature for road safety ITS applications considering urban and highway traffic environment. This paper characterizes vehicular environments based on real traffic data and investigates the evolution of location-centric data dissemination. The current study is carded out with three main objectives： （i） to analyze the impact of dynamic traffic environment on the design of data dissemination techniques, （ii） to characterize location-centric data dissemination in terms of functional and qualitative behavior of protocols, properties, and strengths and weaknesses, and （iii） to find some future research directions in information dissemination based on location. Vehicular traffic environments have been classified into three categories based on physical characteristics such as speed, inter-vehicular distance, neighborhood stability, traffic volume, etc. Real traffic data is considered to analyze on-road traffic environments based on the measurement of physical parameters and weather conditions. Design issues are identified in incorporating physical parameters and weather conditions into data dissemination. Functional and qualitative characteristics of location-centric techniques are explored considering urban and highway environments. Comparative analysis of location-centric techniques is carded out for both urban and highway environments individually based on some unique and common characteristics of the environments. Finally, some future research directions are identified in the area based on the detailed investigation of traffic environments and location-centric data dissemination techniques.
基金This work was supported by the National Natural Science Foundation of China(Grant No.81773083)the Scientific and Technological Innovation Leading Talent Project of Liaoning Province(Grant No.XLYC1802108)the Support Project for Young and Technological Innovation Talents of Shenyang(Grant No.RC190393).
文摘Objective:Neoadjuvant chemotherapy(NAC)is currently used in both early stage and locally advanced breast cancers.The survival benefits of standard vs.non-standard NAC cycles are still unclear.This study aimed to investigate the relationship between NAC cycles and survival based on real world data.Methods:We identified patients diagnosed with invasive primary breast cancers who underwent NAC followed by surgery.Patients who received at least 4 NAC cycles were defined as having received standard cycles,while patients who received less than 4 NAC cycles were defined as having received non-standard cycles.Kaplan-Meier curves and Cox proportional hazard models were used to estimate the disease-free survival(DFS)and overall survival(OS).Results:Of the 1,024 included patients,700 patients received standard NAC cycles and 324 patients received non-standard NAC cycles.The DFS estimates were 87.1%and 81.0%(P=0.007)and the OS estimates were 90.0%and 82.6%(P=0.001)in the standard and non-standard groups,respectively.Using multivariate analyses,patients treated with standard NAC cycles showed significant survival benefits in both DFS[hazard ratio(HR):0.62,95%confidence interval(CI):0.44–0.88]and OS(HR:0.54,95%CI:0.37–0.79).Using stratified analyses,standard NAC cycles were associated with improved DFS(HR:0.59,95%CI:0.36–0.96)and OS(HR:0.49,95%CI:0.28–0.86)in the HER2 positive group.Similar DFS(HR:0.50,95%CI:0.25–0.98)and OS(HR:0.45,95%CI:0.22–0.91)benefits were shown for the triple negative group.Conclusions:Standard NAC cycles were associated with a significant survival benefit,especially in patients with HER2 positive or triple negative breast cancer.
文摘We propose a novel stochastic modeling framework for coal production and logistics using option pricing theory.The problem of valuing the inherent real optionality a coal producer has when mining and processing thermal coal is modelled as pricing spread options of three assets under the stochastic volatility model.We derive a three-dimensional Fast Fourier Transform(“FFT”)lower bound approximation to value the inherent real optionality and for robustness check,we compare the semi-analytical pricing accuracy with the Monte Carlo simulation.Model parameters are estimated from the historical monthly data,and stochastic volatility parameters are obtained by matching the Kurtosis of the low-ash diff data to the Kurtosis of the stochastic volatility process which is assumed to follow Cox–Ingersoll–Ross(“CIR”)model.
基金European Commission(CZ.10.03.01/00/22-003/0000048)Fundacao para a Ciencia e a Tecnologia(PTDC/EEI-EEE/0415/2021),CICECO(UIDB/50011/2020,UIDP/50011/2020,LA/P/0006/2020)+1 种基金VSB-Technical University of Ostrava(SP2025/039)FCT/MCTES(UI/BD/153066/2022)。
文摘In the food production sector,quickly identifying potential hazards is crucial due to the resilience of many pathogens,which could lead to wasted production results and,more severely,epidemic outbreaks.E.coli monitoring is essential;however,traditional quality control methods in fish farming are often slow and intrusive,thus promoting an increase in fish stress and mortality rates.This paper presents an alternative method by utilizing a prototype inspired by polarized optical microscopy(POM),constructed with a Raspberry Pi microprocessor to assess pixel patterns and calculate analyte levels.
文摘SUMMARIES OF TOP NEWS STORIES CHINA Safeguarding Gaokao Fairness This year’s gaokao,China’s national college entrance exam,began on 7 June,with a record 13.35 million students taking part.As one of the country’s most important annual events,the 2025 gaokao has seen extensive nation-wide efforts to ensure fairness,safety,and support for all candidates.Authorities have implemented a range of security and logistical measures to safeguard exam integrity.AI-powered monitoring systems have been rolled out in provinces like Jiangxi,Hubei,and Guangdong,enabling real-time behaviour analysis and early warnings without human intervention.These tools reduce pressure on staff and strengthen fairness.
基金supported by Aero Propulsion Test and Demonstration of Commission of Science and Technology and Industry for Nation Defense,China (Grant No. APTD-1001B)
文摘Although a great deal of research has been dedicated to the synthesis of spiral bevel gears, little related to reverse engineering can be found. An approach is proposed to reverse the machine-tool settings of the pinion of a spiral bevel gear drive on the basis of the blank and tooth surface data obtained by a coordinate measuring machine(CMM). Real tooth contact analysis(RTCA) is performed to preliminary ascertain the contact pattern, the motion curve, as well as the position of the mean contact point. And then the tangent to the contact path and the motion curve are interpolated in the sense of the least square method to extract the initial values of the bias angle and the higher order coefficients(HOC) in modified roll motion. A trial tooth surface is generated by machine-tool settings derived from the local synthesis relating to the initial meshing performances and modified roll motion. An optimization objective is formed which equals the tooth surface deviation between the real tooth surface and the trial tooth surface. The design variables are the parameters describing the meshing performances at the mean contact point in addition to the HOC. When the objective is optimized within an arbitrarily given convergence tolerance, the machine-tool settings together with the HOC are obtained. The proposed approach is verified by a spiral bevel pinion used in the accessory gear box of an aviation engine. The trial tooth surfaces approach to the real tooth surface on the whole in the example. The results show that the convergent tooth surface deviation for the concave side on the average is less than 0.5 μm, and is less than 1.3 μm for the convex side. The biggest tooth surface deviation is 6.7 μm which is located at the corner of the grid on the convex side. Those nodes with relative bigger tooth surface deviations are all located at the boundary of the grid. An approach is proposed to figure out the machine-tool settings of a spiral bevel pinion by way of reverse engineering without having known the theoretical tooth surfaces and the corresponding machine-tool settings.
基金This work was financially supported by the National Natural Science Foundation of China(Grant Nos.21275012 and 21175008).
文摘Ambient mass spectrometry facilitates surface detection under ambient conditions and has quickly found its applications in various areas.However,the sensitivity of AMS methods is usually not as good as that of encapsulated ion sources due to less efficient ion transmission.In this work,a briefly machined external ion funnel(threepole electrostatic lens)was adopted and installed between direct analysis in real time and the mass spectrometer inlet to increase detection sensitivity.Software investigation with SIMION version 8.0 was employed to calculate electric fields and to simulate the trajectories of charged particles in the electric field.Both the geometrical parameters of the ion funnel and the electric parameters were studied to obtain the optimal ion focusing results,which demonstrated the ion funnel equipment would greatly improve the ion transmission efficiency.The equipment showed good prospect in direct analysis in real time-mass spectrometry analysis in the future.
基金the National Natural Science Foundation of China(No.21575092)for financial support
文摘An environmentally friendly,low power consuming,sensitive and compact mercury analyzer was developed for the determination of mercury in water samples by integrating a thin film dielectric barrier discharge induced cold vapor reactor and a dielectric barrier discharge optical emission spectrometer into a small polymethyl methacrylate plate（10.5 cm length×8.0 cm width×1.2 cm height）.Mercury cold vapor was generated when standard or sample solutions with or without formic acid were introduced to the reactor to form thin film liquid and exposed to microplasma irradiation and subsequently separated from the liquid phase for transport to the microplasma and detection of its atomic emission.Limits of detection of 0.20 μg L^-1 and 2.6 μg L^-1 were obtained for the proposed system using or not using formic acid,respectively.Compared to the conventional microplasma optical emission spectrometry used for mercury analysis,this system not only retains the good limit of detection amenable to the determination of mercury in real samples,but also reduces power consumption,eliminates the generation of hydrogen and avoids the use of toxic or unstable reductant.Method validation was demonstrated by analysis of a certified reference material of water sample and three real water samples with good spike recoveries（88-102%）.
基金support from National Natural Science Foundation of China(Nos.21172250 and 21275155).
文摘A method for rapid identification and quantification of phthalate plasticizers in beverages was developed.A number of 15 phthalate plasticizers which covered all the phthalates concerned in the US Consumer Product Safety Improvement Act(CPSIA),European Union legislations and Chinese national standards(GB)were analyzed.By a combined solid-phase micro-extraction(SPME)and direct analysis in real time mass spectrometry(DART-MS)approach,phthalates at sub-ng•mL^(−1)levels can be qualitatively and quantitatively analyzed in a short time.The use of ultrahigh-resolving power and the accurate mass measurement capacity naturally provided by Fourier transform ion cyclotron resonance mass spectrometry(FT-ICR-MS)minimizes the matrix interferences and thus enables the evaluation of phthalates in a complex matrix without extensive sample handlings or preparations.The limits of quantification(LOQs)were estimated to be at 0.3-5.0 ng•mL^(−1),lower than the Maximum Residue Limit(MRL)regulated by the European Union legislations(2007/19/EC)in foods,beverages,food packaging and toys(0.3-30 ng•mL^(−1)).This rapid and easy-to-use SPME-DART-FT-ICR-MS method provided a relatively high-throughput and powerful analytical approach for quick testing and screening phthalates in beverages and water samples to ensure food safety.
基金This research was supported by the Project for Strengthening the Police Force with Science and Technology(project number 2018GABJC29).
文摘We aimed to establish for the rapid detection of morphine,O6‑monoacetylmorphine,heroin,codeine,cocaine,methamphetamine,ketamine,methadone,and dolantin in human blood and urine by direct analysis in real‑time coupled with tandem mass spectrometry(DART‑MS/MS).These samples were extracted by acetonitrile‑methanol(V/V=4:1),using DART 12 Dip‑it automatic sampling system.They were injected at 400℃,and analyzed by positive ion and multiple reaction monitoring mode.The detection limits of morphine,O6‑Monoacetylmorphine,heroin,codeine,cocaine,methamphetamine,ketamine,methadone,and dolantin were 100,50,50,100,20,20,10,1,and 0.01 ng/mL,respectively.The practical cases contained methamphetamine,codeine,cocaine,and O6‑monoacetylmorphine were detected accurately and rapidly.The method has the advantages of high sensitivity and good accuracy.The sample processing is simple and can be analyzed in a short time.This method is suitable for the analysis of morphine,O6‑monoacetylmorphine,heroin,codeine,cocaine,methamphetamine,ketamine,methadone,and dolantin in some practical cases.
文摘This paper,through mass spectrometric(MS)analysis for nitro compound explosives on a direct analysis in a real‑time time‑of‑flight MS,indicates that even on a high‑resolution MS with accurate mass measurement capabilities,there is no guarantee to obtain the unique molecular formula of a compound.By calculating spectra accuracy,highly accurate isotope pattern matching can be conducted to significantly improve performance of compound confirmation or identification.
文摘Direct analysis in real time(DART) possesses the merits of analyzing sample in its native status with minimal or even no sample pretreatment.In this review, we summarized the recent applications of DART in the field of herbal medicine analysis such as compound detection, species identification, metabolites profiling and initial quantification. DART with the characters of hyper-rapid, easy-hyphenated offers a new research tool for herbal medicines to complete the experimental process in a very simple but still reliable way. It is anticipated that more wide and deep applications of DART in herbal medicine analysis, as rapid quantification, high-throughput active compounds screening, rapid species identification, and fast illegal additives screening will be promising and foreseeable in the near future.
基金supported by the National Natural Science Foundation of China(82273684)。
文摘The measurement of amino acid and monoamine neurotransmitters(NTs)in serum plays a central role in the identification and monitoring of clinical panic disorder(PD).However,the strong polarity and chemical heterogeneity of NTs make direct extraction and rapid detection extremely challenging.Herein,we developed a strategy that integrated solid phase extraction based on magnetic Fe_(3)O_(4)coated with polydopamine(Fe_(3)O_(4)@PDA)and direct analysis of mass spectrometry in real time(DART-MS)for quantification of 10 NTs.We systematically investigated the optimal conditions of this strategy to achieve good accuracy and precision.Compared with existing magnetic solid phase extraction methods for NTs detection in biological samples,this strategy could adsorb more targets while having similar adsorption efficiencies,and the total process time was reduced by an average of 69.42%.We rapidly determined the metabolic abnormality of 6 types of NTs in the serum of PD patients and demonstrated their diagnostic accuracy.In addition,an outstanding feature of PD in which tryptophan was more metabolized by the KYN pathway and the 5-hydroxytryptamine pathway was inhibited could be elucidated by this strategy.Our results highlighted the potential ability of Fe_(3)O_(4)@PDA coupled with DART-MS to assist in the clinical diagnosis of PD.
文摘NiCo2O4 nanosheets with sheaf-like nanostructure morphologies have been synthesized by a facile one-step hydrothermal reaction followed by annealing treatment. Impressively, the NiCo2O4 nanosheets exhibit rapid detection of eugenol. The linear range of detection is from 1-500μM, and the limit of detection is 5.4 μM. The NiCo2O4 modified electrode demonstrated high sensitivity, good repeatability and reproducibility, and long-term stability （7% decrease in response over 30 days）. Based on this work, an electrochemical reaction mechanism for eugenol oxidation was proposed, and in addition, the NiCo2O4 modified electrode was successfully employed for the analysis of eugenol in medicative balm samples. Recovery values for eugenol in medicative balm samples were in the range 98.7%-105.5%.
基金the National Natural Science Foundation of China （No. 10771049 10771050）+1 种基金 the Natural Science Foundation of Hebei Province （No. A2007000225） and the Foundation of Hebei Normal University （No. L2007Q05） the 11th Five-Year Plan Educational and Scientific Issues of Hebei Province （No. O8020147）.
文摘In the first part of this paper, we discuss the Holder continuity of the cauchy integral operator for regular functions and the relation between ‖T{f}‖α and ‖f‖α. In the second part of this paper, we introduce the modified cauchy integral operator T^- for regular functions. Firstly, we prove that the operator T^- has a unique fixed point by the Banach＇s Contraction Mapping Principle. Secondly, we give the Mann iterative sequence, and then we show the iterative sequence strongly converges to the fixed point of the operator T^-.
基金supported by the National Natural Science Foundation of China under Grant Nos.12201079,12201004,and 11871072the National Social Science Foundation of China under Grant No.22BTJ059+1 种基金the Natural Science Foundation of Anhui Province under Grant Nos.2108085QA15 and 2108085MA06the“INSA Senior Scientist”scheme at the CR Rao Advanced Institute of Mathematics,Statistics and Computer Science,Hyderabad 500046,India.
文摘In this paper,the authors study a class of weighted version of probability density estimator.It is shown that the weighted estimator contains some existing estimators of probability density,no matter they are recursive or non-recursive.Some statistical results including weak consistency,strong consistency,rate of strong consistency,and asymptotic normality are established under some mild conditions.Moreover,the random weighted estimator is also investigated.Some numerical simulations and a real data analysis are presented to study the numerical performances of the estimators.
文摘Corporations need to improve business processes in order to enhance velocity and service levels while reducing their processing costs and differentiating themselves in the face of competition. The levitation of importance beyond support roles has raised IT investment decisions to high priority in chief executive officers＇ agendas. Corporate planning groups as well as lines of business are increasingly applying techniques of IT applications portfolio management in a more systematic fashion to improve decision-making and resource-allocation processes. Recent advances in software engineering and IT service delivery methodologies have achieved the logical separation of business functions from implementation. This separation has made a new breed of innovative IT project possible with a new project risk structure; the adjustment of portfolio management techniques is appropriate. We present an integrated portfolio management model so that the corporation can focus on organic growth through sources at both the department and top management levels. The research gives clear advice as to how top management can seek economic growth by selecting an entrepreneurial strategic posture, implying a strong risk-taking propensity. By integrating a risk-return model and risk-tolerance paradigm to cope with today＇s risk structure, overall capabilities can improve the decision process and the corporation＇s performance as well. The application of the integrated technique to a Japanese manufacturing firm is described.
