期刊文献+
共找到3,368篇文章
< 1 2 169 >
每页显示 20 50 100
Determination of Heroin Based on Analyte Pulse Perturbation to an Oscillating Chemical Reaction 被引量:4
1
作者 RENJie GAOJin-zhang +5 位作者 Suo-nan ZHAOGuo-hu YANGWu LüDong-yu SUNKan-jun LIChong-yang 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2004年第5期534-538,共5页
A new analytical method is proposed for the determination of heroin based on a sequential perturbation caused by trace amounts of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction between hydrogen peroxide and sodiu... A new analytical method is proposed for the determination of heroin based on a sequential perturbation caused by trace amounts of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction between hydrogen peroxide and sodium thiocyanate in an alkaline medium with the aid of a continuous-flow stirred tank reactor(CSTR). The method relies on the linear relationship between the change in oscillation period of the system and the concentration of heroin, with a detecting limit of 4.0×10^(-7) mol/L. The calibration curve fits a linear equation very well when the concentration of heroin is in the range of 2.0×10^(-6)_1.2×10^(-5) mol/L(r=0.9971). This method features good precision(RSD=0.98%). The influences of temperature, injection point, flow rate and reaction variables on the oscillation period were investigated in detail and a possible mechanism of the performance of heroin in the Cu(Ⅱ)-catalyzed oscillating reaction system is also discussed. The proposed method opens a new avenue for the determination of heroin. 展开更多
关键词 Cu(Ⅱ)-catalyzed oscillating reaction HEROIN analyte pulse perturbation technique(APP) Mechanism Continuous-flow stirred tank reactor(CSTR).
在线阅读 下载PDF
Application of quartz crystal nanobalance in conjunction with a net analyte signal based method for simultaneous determination of leucine, isoleucine and valine 被引量:1
2
作者 Maryam Shojaei Abdolreza Mirmohseni Maryam Farbodi 《Journal of Biomedical Science and Engineering》 2009年第7期532-537,共6页
The aim of the present investigation was to develop a biosensor for the detection of amino acids, Leucine, Isoleucine and Valine based on a quartz crystal nanobalance. leucine (Leu), isoleucine (Ile), and valine (Val)... The aim of the present investigation was to develop a biosensor for the detection of amino acids, Leucine, Isoleucine and Valine based on a quartz crystal nanobalance. leucine (Leu), isoleucine (Ile), and valine (Val) were selectively determined by quartz crystal nanobalance (QCN) sensor in conjunction with net analyte signal (NAS)-based method called HLA/GO. An orthogonal design was applied for the formation of calibration and prediction sets including Leu, Ile and Val compounds. The selection of the optimal time range involved the calculation of the net analyte sig-nal regression plot in any considered time window for each test sample. The searching of a region with maximum linearity of NAS regression plot (minimum error indicator) and minimum of PRESS value was carried out by applying a moving window strategy. On the base of obtained results, the differences on the adsorption profiles in the time range between 1 and 300 s were used to determine mixtures of compounds by HLA/GO method. The results showed that the method was successfully applied for the determina-tion of Leu, Ile and Val. 展开更多
关键词 QUARTZ Crystal Nanobalance Net analyte Signal LEUCINE ISOLEUCINE VALINE HLA/GO Method
暂未订购
Efficient concentration of trace analyte with ordered hotspot construction for a robust and sensitive SERS platform
3
作者 Youdi Hu Yanlei Hu +4 位作者 Zhenyu Wang Jiale Yong Wei Xiong Dong Wu Shixiang Xu 《International Journal of Extreme Manufacturing》 SCIE EI CAS CSCD 2024年第3期532-542,共11页
Surface-enhanced Raman scattering(SERS)platform,which enables trace analyte detection,has important application prospects.By structuring/modifying the surface of the SERSsubstrate,analyte in highly diluted solutions c... Surface-enhanced Raman scattering(SERS)platform,which enables trace analyte detection,has important application prospects.By structuring/modifying the surface of the SERSsubstrate,analyte in highly diluted solutions can be concentrated into localized active areas for highly sensitive detection.However,subject to the difficulty of the fabrication process,itremains challenging to balance hot-spot construction and the concentration capacity of analyte simultaneously.Therefore,preparing SERS substrates with densely ordered hot spots andefficient concentration capacity is of great significance for highly sensitive detection.Herein,we propose an Ag and fluoroalkyl-modified hierarchical armour substrate(Ag/F-HA),which has a double-layer stacking design to combine analyte concentration with hotspot construction.The microarmour structure is fabricated by femtosecond-laser processing to serve as asuperhydrophobic and low-adhesive surface to concentrate analyte,while the anodic aluminium oxide(AAO)template creates a nanopillar array serving as dense and ordered hot spots.Under the synergistic action of hot spots and analyte concentration,Ag/F-HA achieves a detectionlimit down to 10^(-7)M doxorubicin(DOX)molecules with a RSD of 7.69%.Additionally,Ag/F-HA exhibits excellent robustness to resist external disturbances such as liquid splash or abrasion.Based on our strategy,SERS substrates with directional analyte concentrations are further explored by patterning microcone arrays with defects.This work opens a way to the realistic implementation of SERS in diverse scenarios. 展开更多
关键词 surface-enhanced Raman scattering anodic aluminium oxide femtosecond laser processing concentration of trace analytes mechanical robustness
在线阅读 下载PDF
Detecting Concentration of Analytes with DETECHIP: A Molecular Sensing Array
4
作者 Hannah Johnke Gary Batres +2 位作者 Mark Wilson Andrea E. Holmes Sharmin Sikich 《Journal of Sensor Technology》 2013年第3期94-99,共6页
DETECHIP is a detection system made of various sensors that has been shown to detect and discriminate between small molecules of interest, including various illicit and over-the-counter drugs. Previously, detection wa... DETECHIP is a detection system made of various sensors that has been shown to detect and discriminate between small molecules of interest, including various illicit and over-the-counter drugs. Previously, detection was normalized to a single concentration of analyte. Now this detection assay can detect concentration differences in analytes via red, green, and blue color value changes and shifts in the UV-Vis spectra of the assay. To determine the concentrations differences, the exposed assays were scanned on a flatbed scanner and the images were analyzed for individual RGB values with a custom macro in ImageJ, an image analysis program. Increasing concentrations of the analyte resulted in greater differences in color values between control and analyte wells. These differences showed a linear relationship to concentration change, some with correlation coefficients greater than 98%. This work expands the capability of DETECHIP to give information about the concentration of analyte when the analyte identity is known. 展开更多
关键词 COLORIMETRIC ARRAYS Sensors analyte CONCENTRATION RGB Analysis DRUG Detection
暂未订购
Simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation by ultra-high performance liquid chromatography coupled with nano quantity analyte detector 被引量:1
5
作者 Honggen Zhang ZhenyuWang Oscar Liu 《Journal of Pharmaceutical Analysis》 SCIE CAS 2016年第1期11-17,共7页
A novel method for simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation was developed using ultra-high performance liquid chromatography coupled with a nano quantitation analytical... A novel method for simultaneous determination of kolliphor HS15 and miglyol 812 in microemulsion formulation was developed using ultra-high performance liquid chromatography coupled with a nano quantitation analytical detector (UHPLC-NQAD). All components in kolliphor HS15 and miglyo1812 were well separated on an Acquity BEH C18 column. Mobile phase A was 0.1% trifluoroacetic acid (TFA) in water and mobile phase B was acetonitrile. A gradient elution sequence was programed initially with 60% organic solvent, slowly increased to 100% within 8 min. The flow rate was 0.7 mL/min. Good linearity (r 〉 0.95) was obtained in the range of 27.6-1381.1 μg/mL for polyoxyl 15 hydroxystearate in kolliphor HS15, 0.8-202.0 μg/mL for caprylic acid triglyceride and 2.7-221.9μg/mL for capric acid triglyceride in miglyol 812. The relative standard deviations (RSD) ranged from 0.6% to 1.7% for intra-day precision and from 0.4% to 2.7% for inter-day precision. The overall recoveries (accuracy) were 99.7%-101.4% for polyoxyl 15 hydroxystearate in kolliphor HS15, 96.7%-99.6% for caprylic acid triglyceride, and 94.1%- 103.3% for capric acid triglyceride in miglyol 812. Quantification limits (QL) were determined as 27.6 μg/ mL for polyoxy115 hydroxystearate in kolliphor HS15, 0.8 μg/mL for caprylic acid triglyceride, and 2.7 μg/ mL for capric acid triglyceride in miglyol 812. No interferences were observed in the retention time ranges of kolliphor HSI5 and miglyol 812. The method was validated in terms of specificity, linearity, precision, accuracy, QL, and robustness. The proposed method has been applied to microemulsion for- mulation analyses with good recoveries (82.2%-103.4%). 展开更多
关键词 Kolliphor HS15 Miglyol 812 Ultra-high performance liquid chromato-graphy (UHPLC) Nano quantitation analytical detector(NQAD)
在线阅读 下载PDF
Self-calibrating multiplexed microneedle electrode array for continuous mapping of subcutaneous multi-analytes in diabetes
6
作者 Xiangling Li Shantao Zheng +7 位作者 Mengyi He Xinshuo Huang Cheng Yang Jingshan Mo Jingbo Yang Chengduan Yang Huijiuan Chen Xi Xie 《The Innovation》 2025年第2期60-75,59,共17页
Monitoring multiplexed biochemical markers is beneficial for the comprehensive evaluation of diabetes-associated complications.Techniques for multiplexed analyses in interstitial fluids have often been restricted by t... Monitoring multiplexed biochemical markers is beneficial for the comprehensive evaluation of diabetes-associated complications.Techniques for multiplexed analyses in interstitial fluids have often been restricted by the difficulties of electrode materials in accurately detecting chemicals in complex subcutaneous spaces.In particular,the signal stability of enzyme-based sensing electrodes often inevitably decreases due to enzyme degradation or interference in vivo.In this study,we developed a self-calibrating multiplexed microneedle(MN)electrode array(SC-MMNEA)capable of continuous,real-time monitoring of multiple types of bioanalytes(glucose,cholesterol,uric acid,lactate,reactive oxygen species[ROSs],Na+,K+,Ca2+,and pH)in the subcutaneous space.Each type of analyte was detected by a discrete MN electrode assembled in an integrated array with single-MN resolution.Moreover,this device utilized an MN-delivery-mediated self-calibration technique to address the inherent problem of decreased accuracy of implantable electrodes caused by long-term tissue variation and enzyme degradation,and this technique might increase the reliability of the MN sensors.Our results indicated that SC-MMNEA could provide real-time monitoring of multiplexed analyte concentrations in a rat model with good accuracy,especially after self-calibration.SC-MMNEA has the advantages of in situ and minimally invasive monitoring of physiological states and the potential to promote wearable devices for long-term monitoring of chemical species in vivo. 展开更多
关键词 multiplexed analyses monitoring multiplexed biochemical markers continuous mapping multiplexed microneedle electrode array self calibrating subcutaneous multi analytes electrode materials
原文传递
Cnidarian tentacle-inspired microfluidic patch for improved analyte distribution in multiplex sweat sensing
7
作者 Surya Manisha Inukonda Siddhartha Panda 《npj Flexible Electronics》 2025年第1期718-732,共15页
A wearable multiplex sweat sensing patch with low sweat volume requirement and uniform distribution is highly desirable for noninvasive,real-time monitoring of various health-related biomarkers.The patch features a mu... A wearable multiplex sweat sensing patch with low sweat volume requirement and uniform distribution is highly desirable for noninvasive,real-time monitoring of various health-related biomarkers.The patch features a multi-channel microfluidic system inspired by cnidarians.It comprises of symmetric super-hydrophilic/super-hydrophobic patterned wedge channels allowing for simultaneous analysis of multiple analytes present in sweat.It ensures a uniform sweat transport and equal volume distribution across multiple sensing zones for a more accurate and reliable electrochemical sensing.As a proof of concept,a four-channel system housing sensors for glucose,lactate,urea,and pH was tested.The innovation lies in a unique surface design and electrode configuration utilizing PDMS-TiO_(2)nanocomposite coating,integrating channels with electrodes,presenting a novel approach for accurate low-volume sweat analysis requiring a minimum of 4µL.An on-body test was conducted to demonstrate the practical application of the patch.In addition,the physics of droplet splitting was explained through simulations. 展开更多
关键词 microfluidic patch equal volume distribution multiplex sweat sensing patch sweat sensing cnidarian inspired microfluidic system multiplex sensing analysis multiple analytes
原文传递
A versatile biosensing platform coupling CRISPR-Cas12a and aptamers for detection of diverse analytes 被引量:6
8
作者 Xiangxiang Zhao Shanshan Li +13 位作者 Guang Liu Zhong Wang Zhiheng Yang Quanwei Zhang Mindong Liang Jiakun Liu Zilong Li Yaojun Tong Guoliang Zhu Xinye Wang Lan Jiang Weishan Wang Gao-Yi Tan Lixin Zhang 《Science Bulletin》 SCIE EI CSCD 2021年第1期69-77,M0004,共10页
Rapid and sensitive detection of various analytes is in high demand.Apart from its application in genome editing,CRISPR-Cas also shows promises in nucleic acid detection applications.To further exploit the potential o... Rapid and sensitive detection of various analytes is in high demand.Apart from its application in genome editing,CRISPR-Cas also shows promises in nucleic acid detection applications.To further exploit the potential of CRISPR-Cas for detection of diverse analytes,we present a versatile biosensing platform that couples the excellent affinity of aptamers for broad-range analytes with the collateral single-strand DNA cleavage activity of CRISPR-Cas12 a.We demonstrated that the biosensors developed by this platform can be used to detect protein and small molecule in human serum with a complicated background,i.e.,the tumor marker alpha fetoprotein and cocaine with the detection limits of 0.07 fmol/L and 0.34 lmol/L,respectively,highlighting the advantages of simplicity,sensitivity,short detection time,and low cost compared with the state-of-the-art biosensing approaches.Altogether,this biosensing platform with plug-and-play design show great potential in the detection of diverse analytes. 展开更多
关键词 CRISPR–Cas12a Aptamer Biosensing platform Diverse analyte Alpha fetoprotein detection Cocaine detection
原文传递
Wave Energy System Combined by a Heaving Box and a Perforated Flexible Membrane Wall
9
作者 Sarat Chandra Mohapatra C.Guedes Soares 《哈尔滨工程大学学报(英文版)》 2026年第1期110-121,共12页
An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduc... An analytical model of a floating heaving box integrated with a vertical flexible porous membrane placed right next to the box applications to wave energy extraction and breakwater systems is developed under the reduced wave equation.The theoretical solutions for the heave radiating potential to the assigned physical model in the corresponding zones are attained by using the separation of variables approach along with the Fourier expansion.Applying the matching eigenfunction expansion technique and orthogonal conditions,the unknown coefficients that are involved in the radiated potentials are determined.The attained radiation potential allows the computation of hydrodynamic coefficients of the heaving buoy,Power Take-Off damping,and wave quantities.The accuracy of the analytical solution for the hydrodynamic coefficients is demonstrated for different oblique angles with varying numbers of terms in the series solution.The current analytical analysis findings are confirmed by existing published numerical boundary element method simulations.Several numerical results of the hydrodynamic coefficients,power capture,power take-off optimal damping,and transmission coefficients for numerous structural and physical aspects are conducted.It has been noted that the ideal power take-off damping increases as the angle of incidence rises,and the analysis suggests that the ability to capture waves is more effective in shallower waters compared to deeper ones. 展开更多
关键词 Analytical model Heaving buoy Flexible membrane perforated wall Boundary element method code Power take-off Power capture
在线阅读 下载PDF
Rapid Sensing of Biological and Environmental Analytes Using Microwave-Accelerated Bioassays and a MATLAB Application
10
作者 Enock Bonyi Edward Constance +2 位作者 Zeenat Kukoyi Sanjeeda Jafar Kadir Aslan 《Nano Biomedicine & Engineering》 2019年第2期111-123,共13页
We report a method for rapid detection and analysis of biological and environmental analytes by microwave-accelerated bioassays(MABs)and a novel MATLAB-based image processing of colorimetric signals.In this regard,col... We report a method for rapid detection and analysis of biological and environmental analytes by microwave-accelerated bioassays(MABs)and a novel MATLAB-based image processing of colorimetric signals.In this regard,colorimetric bioassays for histidine-rich protein 2(HRP-2)and microcystin-leucine arginine(MC-LR)toxin were carried out using MABs and without microwave heating(i.e,gold standard bioassays).Our MATLAB-based detection method is based on the direct correlation of color intensity of a solution calculated from images captured with a smartphone with the concentration of the biomolecule of interest using a MATLAB code developed in-house.We demonstrated that our MATLAB-based detection method can yield bioassay sensitivity comparable to the colorimetric gold standard tool,i.e.,UV-Visible spectroscopy.In addition,colorimetric bioassay time for the HRP-2 assay(used in malaria diagnosis)and colorimetric MC-LR bioassay(used in MC-LR toxin diagnosis)was reduced from up to 2 hours at room temperature without microwave heating to 15 minutes using the MABs technique. 展开更多
关键词 analyte Colorimetric bioassays Microwave-accelerated bioassays Microwave heating MATLAB
在线阅读 下载PDF
基于FAHP-TOPSIS法的地下空间开发地质适宜性评价
11
作者 李浩民 瞿婧晶 张其琪 《科学技术与工程》 北大核心 2025年第30期13187-13196,共10页
为了客观评价地下空间开发地质适宜性并为评价工作提供一种新思路和参考,提出了一种基于三角模糊数的模糊层次分析法(fuzzy analytic hierarchy process based on triangular fuzzy numbers,FAHP)和优劣解距离法(technique for order pr... 为了客观评价地下空间开发地质适宜性并为评价工作提供一种新思路和参考,提出了一种基于三角模糊数的模糊层次分析法(fuzzy analytic hierarchy process based on triangular fuzzy numbers,FAHP)和优劣解距离法(technique for order preference by similarity to ideal solution,TOPSIS)相结合的评价方法。通过地质调查研究构建基于土体工程地质性质、水文地质条件、不良地质作用、地形地貌等影响因素为主的层次分析关系模型。基于专家判别利用FAHP计算各评价因素的权重,以各评价指标层的分级临界值作为典型评价样本,利用TOPSIS法对适宜性等级进行非等分划分,基于区间值优化的TOPSIS法建立最终评价模型,通过ArcGIS的空间分析功能等确定每个评价单元适宜性等级。该方法与传统方法相比一定程度上减少了评价过程中专家评判的过多主观影响,评价过程更倾向于定量化,结果更为客观。利用该方法对无锡市区浅层地下空间开发地质适宜性进行评价,评价结果与实际工程经验相符,证明了该方法的有效性,因此该方法对地下空间开发适宜性评价工作具有一定借鉴意义。 展开更多
关键词 FAHP(fuzzy analytic hierarchy process) TOPSIS(technique for order preference by similarity to an ideal solution) 城市地下空间 地质适宜性评价
在线阅读 下载PDF
Smart cities,smart systems:A comprehensive review of system dynamics model applications in urban studies in the big data era 被引量:2
12
作者 Gift Fabolude Charles Knoble +1 位作者 Anvy Vu Danlin Yu 《Geography and Sustainability》 2025年第1期25-36,共12页
This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models ... This paper addresses urban sustainability challenges amid global urbanization, emphasizing the need for innova tive approaches aligned with the Sustainable Development Goals. While traditional tools and linear models offer insights, they fall short in presenting a holistic view of complex urban challenges. System dynamics (SD) models that are often utilized to provide holistic, systematic understanding of a research subject, like the urban system, emerge as valuable tools, but data scarcity and theoretical inadequacy pose challenges. The research reviews relevant papers on recent SD model applications in urban sustainability since 2018, categorizing them based on nine key indicators. Among the reviewed papers, data limitations and model assumptions were identified as ma jor challenges in applying SD models to urban sustainability. This led to exploring the transformative potential of big data analytics, a rare approach in this field as identified by this study, to enhance SD models’ empirical foundation. Integrating big data could provide data-driven calibration, potentially improving predictive accuracy and reducing reliance on simplified assumptions. The paper concludes by advocating for new approaches that reduce assumptions and promote real-time applicable models, contributing to a comprehensive understanding of urban sustainability through the synergy of big data and SD models. 展开更多
关键词 Urban sustainability Smart cities System dynamics models Big data analytics Urban system complexity Data-driven urbanism
在线阅读 下载PDF
Integration of data science with the intelligent IoT(IIoT):Current challenges and future perspectives 被引量:2
13
作者 Inam Ullah Deepak Adhikari +3 位作者 Xin Su Francesco Palmieri Celimuge Wu Chang Choi 《Digital Communications and Networks》 2025年第2期280-298,共19页
The Intelligent Internet of Things(IIoT)involves real-world things that communicate or interact with each other through networking technologies by collecting data from these“things”and using intelligent approaches,s... The Intelligent Internet of Things(IIoT)involves real-world things that communicate or interact with each other through networking technologies by collecting data from these“things”and using intelligent approaches,such as Artificial Intelligence(AI)and machine learning,to make accurate decisions.Data science is the science of dealing with data and its relationships through intelligent approaches.Most state-of-the-art research focuses independently on either data science or IIoT,rather than exploring their integration.Therefore,to address the gap,this article provides a comprehensive survey on the advances and integration of data science with the Intelligent IoT(IIoT)system by classifying the existing IoT-based data science techniques and presenting a summary of various characteristics.The paper analyzes the data science or big data security and privacy features,including network architecture,data protection,and continuous monitoring of data,which face challenges in various IoT-based systems.Extensive insights into IoT data security,privacy,and challenges are visualized in the context of data science for IoT.In addition,this study reveals the current opportunities to enhance data science and IoT market development.The current gap and challenges faced in the integration of data science and IoT are comprehensively presented,followed by the future outlook and possible solutions. 展开更多
关键词 Data science Internet of things(IoT) Big data Communication systems Networks Security Data science analytics
在线阅读 下载PDF
Fast and Accurate Prediction of Electromagnetic and Temperature Fields for SPMSM Equipped with Unequally Thick Magnetic Poles 被引量:2
14
作者 Feng Liu Xiuhe Wang +1 位作者 Lingling Sun Hongye Wei 《CES Transactions on Electrical Machines and Systems》 2025年第2期199-211,共13页
With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher ... With the continuous upgrading of traditional manufacturing industries and the rapid rise of emerging technology fields,the performance requirements for the permanent magnet synchronous motors(PMSMs)have become higher and higher.The importance of fast and accurate electromagnetic thermal coupling analysis of such motors becomes more and more prominent.In view of this,the surfacemounted PMSM(SPMSM)equipped with unequally thick magnetic poles is taken as the main object and its electromagnetic thermal coupling analytical model(ETc AM)is investigated.First,the electromagnetic analytical model(EAM)is studied based on the modified subdomain method.It realizes the fast calculation of key electromagnetic characteristics.Subsequently,the 3D thermal analytical model(TAM)is developed by combining the EAM,the lumped parameter thermal network method(LPTNM),and the partial differential equation of heat flux.It realizes the fast calculation of key thermal characteristics in 3D space.Further,the information transfer channel between EAM and TAM is built with reference to the intrinsic connection between electromagnetic field and temperature field.Thereby,the novel ETcAM is proposed to realize the fast and accurate prediction of electromagnetic and temperature fields.Besides,ETcAM has a lot to commend it.One is that it well accounts for the complex structure,saturation,and heat exchange behavior.Second,it saves a lot of computer resources.It offers boundless possibilities for initial design,scheme evaluation,and optimization of motors.Finally,the validity,accuracy,and practicality of this study are verified by simulation and experiment. 展开更多
关键词 Electromagnetic field and temperature field Electromagnetic thermal coupling analytical model(ETcAM) Fast and accurate prediction SPMSM Unequally thick magnetic poles
在线阅读 下载PDF
Geometric size and forming force prediction in incremental flanging:A new analytical model 被引量:1
15
作者 Chong TIAN Dawei ZHANG +1 位作者 Guangcan YANG Shengdun ZHAO 《Chinese Journal of Aeronautics》 2025年第2期519-540,共22页
A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which ca... A new analytical model for geometric size and forming force prediction in incremental flanging(IF)is presented in this work.The complex deformation characteristics of IF are considered in the modeling process,which can accurately describe the strain and stress states in IF.Based on strain analysis,the model can predict the material thickness distribution and neck height after IF.By considering contact area,strain characteristics,material thickness changes,and friction,the model can predict specific moments and corresponding values of maximum axial forming force and maximum horizontal forming force during IF.In addition,an IF experiment involving different tool diameters,flanging diameters,and opening hole diameters is conducted.On the basis of the experimental strain paths,the strain characteristics of different deformation zones are studied,and the stable strain ratio is quantitatively described through two dimensionless parameters:relative tool diameter and relative hole diameter.Then,the changing of material thickness and forming force in IF,and the variation of minimum material thickness,neck height,maximum axial forming force,and maximum horizontal forming force with flanging parameters are studied,and the reliability of the analytical model is verified in this process.Finally,the influence of the horizontal forming force on the tool design and the fluctuation of the forming force are explained. 展开更多
关键词 Incremental flanging Analytical model Strain characteristic Geometric size Forming force
原文传递
Hydraulic fracturing-based analytical method for determining seepage characteristics at tunnel-gasketed joints 被引量:1
16
作者 GONG Chen-jie CHENG Ming-jin +2 位作者 FAN Xuan PENG Yi-cheng DING Wen-qi 《Journal of Central South University》 2025年第4期1520-1534,共15页
Waterproof performance of gaskets between segments is the focus of shield tunnels.This paper proposed an analytical method for determining seepage characteristics at tunnel-gasketed joints based on the hydraulic fract... Waterproof performance of gaskets between segments is the focus of shield tunnels.This paper proposed an analytical method for determining seepage characteristics at tunnel-gasketed joints based on the hydraulic fracturing theories.First,the mathematical model was established,and the seepage governing equation and boundary conditions were obtained.Second,three dimensionless parameters were introduced for simplifying the expressions,and the seepage governing equations were normalized.Third,analytical expressions were derived for the interface opening and liquid pressure.Moreover,the influencing factors of seepage process at the gasketed interface were analyzed.Parametric analyses revealed that,in the normalized criterion of liquid viscosity,the liquid tip coordinate was influenced by the degree of negative pressure in the liquid lag region,which was related to the initial contact stress.The coordinate of the liquid tip affected the liquid pressure distribution and the interface opening,which were analyzed under different liquid tip coordinate conditions.Finally,under two limit states,comparative analysis showed that the results of the variation trend of the proposed method agree well with those of previous research.Overall,the proposed analytical method provides a novel solution for the design of the waterproof in shield tunnels. 展开更多
关键词 shield tunnels segment joints seepage characteristics hydraulic fracture analytical solution
在线阅读 下载PDF
Deformation analysis of ground and existing tunnel induced by overlapped curved shield tunneling 被引量:1
17
作者 Yingnan Liu Huayang Lei +2 位作者 Liang Shi Gang Zheng Mengting Wang 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第2期795-809,共15页
The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield... The deformation caused by tunnel excavation is quite important for safety,especially when it is adjacent to the existing tunnel.Nevertheless,the investigation of deformation characteristics in overlapped curved shield tunneling remains inadequate.The analytical solution for calculating the deformation of the ground and existing tunnel induced by overlapped curved shield tunneling is derived by the Mirror theory,Mindlin solution and Euler-Bernoulli-Pasternak model,subsequently validated through both finite element simulation and field monitoring.It is determined that the overcutting plays a crucial role in the ground settlement resulting from curved shield tunneling compared to straight shield tunneling.The longitudinal settlement distribution can be categorized into five areas,with the area near the tunnel surface experiencing the most dramatic settlement changes.The deformation of the existing tunnel varies most significantly with turning radius compared to tunnel clearance and grouting pressure,especially when the turning radius is less than 30 times the tunnel diameter.The tunnel crown exhibits larger displacement than the tunnel bottom,resulting in a distinctive‘vertical egg'shape.Furthermore,an optimized overcutting mode is proposed,involving precise control of the extension speed and angular velocity of the overcutting cutter,which effectively mitigates ground deformation,ensuring the protection of the existing tunnel during the construction. 展开更多
关键词 Overlapped curved shield tunneling Analytical solution Ground deformation Existing tunnel Overcutting mode
在线阅读 下载PDF
Research Progress on Microfluidic Paper-based Analytical Devices for Point-of-care Testing 被引量:1
18
作者 ZHANG Yuji XU Ruicheng SHAN Dan 《激光生物学报》 2025年第1期1-11,共11页
Point-of-care testing(POCT)refers to a category of diagnostic tests that are performed at or near to the site of the patients(also called bedside testing)and is capable of obtaining accurate results in a short time by... Point-of-care testing(POCT)refers to a category of diagnostic tests that are performed at or near to the site of the patients(also called bedside testing)and is capable of obtaining accurate results in a short time by using portable diagnostic devices,avoiding sending samples to the medical laboratories.It has been extensively explored for diagnosing and monitoring patients’diseases and health conditions with the assistance of development in biochemistry and microfluidics.Microfluidic paper-based analytical devices(μPADs)have gained dramatic popularity in POCT because of their simplicity,user-friendly,fast and accurate result reading and low cost.SeveralμPADs have been successfully commercialized and received excellent feedback during the past several decades.This review briefly discusses the main types ofμPADs,preparation methods and their detection principles,followed by a few representative examples.The future perspectives of the development inμPADs are also provided. 展开更多
关键词 point-of-care testing microfluidic paper-based analytical devices SENSOR personalized medical treatment portable diagnostic equipment
在线阅读 下载PDF
Prediction of lost circulation risk in fractured formations based on 3D geomechanical modeling 被引量:1
19
作者 Jinfa Zhang Yongcun Feng +4 位作者 Sijia Ma Zhijuan Hao Bing He Jingyi Wei Jingen Deng 《International Journal of Mining Science and Technology》 2025年第11期1955-1973,共19页
Due to complex geological structures and a narrow safe mud density window,offshore fractured formations frequently encounter severe lost circulation(LC)during drilling,significantly hindering oil and gas exploration a... Due to complex geological structures and a narrow safe mud density window,offshore fractured formations frequently encounter severe lost circulation(LC)during drilling,significantly hindering oil and gas exploration and development.Predicting LC risks enables the targeted implementation of mitigation strategies,thereby reducing the frequency of such incidents.To address the limitations of existing 3D geomechanical modeling in predicting LC,such as arbitrary factor selection,subjective weight assignment,and the inability to achieve pre-drilling prediction along the entire well section,an improved prediction method is proposed.This method integrates multi-source data and incorporates three LC-related sensitivity factors:fracture characteristics,rock brittleness,and in-situ stress conditions.A quantitative risk assessment model for LC is developed by combining the subjective analytic hierarchy process with the objective entropy weight method(EWM)to assign weights.Subsequently,3D geomechanical modeling is applied to identify regional risk zones,enabling digital visualization for pre-drilling risk prediction.The developed 3D LC risk prediction model was validated using actual LC incidents from drilled wells.Results were generally consistent with field-identified LC zones,with an average relative error of 19.08%,confirming its reliability.This method provides practical guidance for mitigating potential LC risks and optimizing drilling program designs in fractured formations. 展开更多
关键词 Fractured formations Lost circulation risk Geomechanical modeling Geological-engineering integration Analytic hierarchy process Entropy weight method
在线阅读 下载PDF
Galerkin-Vlasov approach for bending analysis of flexoelectric doubly-curved sandwich nanoshells with piezoelectric/FGP/piezoelectric layers using the nonlocal strain theory 被引量:1
20
作者 Tran Van Ke Do Van Thom +2 位作者 Nguyen Thai Dung Nguyen Van Chinh Phung Van Minh 《Acta Mechanica Sinica》 2025年第2期7-40,共34页
Flexoelectricity refers to the link between electrical polarization and strain gradient fields in piezoelectric materials,particularly at the nano-scale.The present investigation aims to comprehensively focus on the s... Flexoelectricity refers to the link between electrical polarization and strain gradient fields in piezoelectric materials,particularly at the nano-scale.The present investigation aims to comprehensively focus on the static bending analysis of a piezoelectric sandwich functionally graded porous(FGP)double-curved shallow nanoshell based on the flexoelectric effect and nonlocal strain gradient theory.Two coefficients that reduce or increase the stiffness of the nanoshell,including nonlocal and length-scale parameters,are considered to change along the nanoshell thickness direction,and three different porosity rules are novel points in this study.The nanoshell structure is placed on a Pasternak elastic foundation and is made up of three separate layers of material.The outermost layers consist of piezoelectric smart material with flexoelectric effects,while the core layer is composed of FGP material.Hamilton’s principle was used in conjunction with a unique refined higher-order shear deformation theory to derive general equilibrium equations that provide more precise outcomes.The Navier and Galerkin-Vlasov methodology is used to get the static bending characteristics of nanoshells that have various boundary conditions.The program’s correctness is assessed by comparison with published dependable findings in specific instances of the model described in the article.In addition,the influence of parameters such as flexoelectric effect,nonlocal and length scale parameters,elastic foundation stiffness coefficient,porosity coefficient,and boundary conditions on the static bending response of the nanoshell is detected and comprehensively studied.The findings of this study have practical implications for the efficient design and control of comparable systems,such as micro-electromechanical and nano-electromechanical devices. 展开更多
关键词 Analytical solution Flexoelectric effect Nonlocal strain gradient theory Static bending of nanoshell
原文传递
上一页 1 2 169 下一页 到第
使用帮助 返回顶部