期刊文献+
共找到296篇文章
< 1 2 15 >
每页显示 20 50 100
Meta-analysis evidence supporting foot reflexology for nausea and vomiting management:Additional insights to recent systematic review
1
作者 Vaishnu Karthik KAMARAJ Yeswanth Kumaran VENKATACHALAM +1 位作者 Deenadayalan BOOPALAN Maheshkumar KUPPUSAMY 《Journal of Integrative Nursing》 2025年第3期179-180,共2页
Dear Editor,We read with a great interest the recently published systematic review by Shamsikhani and Hosseini titled,“Foot reflexology on nausea and vomiting:A systematic review.”[1]While the authors provided a com... Dear Editor,We read with a great interest the recently published systematic review by Shamsikhani and Hosseini titled,“Foot reflexology on nausea and vomiting:A systematic review.”[1]While the authors provided a comprehensive qualitative synthesis of six studies meeting their inclusion criteria,we believe that additional quantitative analysis would strengthen the evidence base for foot reflexology in managing nausea and vomiting.We conducted a complementary meta-analysis to provide quantitative evidence supporting the qualitative findings presented in the systematic review. 展开更多
关键词 qualitative synthesis NAUSEA meta analysis foot reflexology systematic review quantitative analysis evidence base
暂未订购
MITRE ATT&CK-Driven Threat Analysis for Edge-IoT Environment and a Quantitative Risk Scoring Model
2
作者 Tae-hyeon Yun Moohong Min 《Computer Modeling in Engineering & Sciences》 2025年第11期2707-2731,共25页
The dynamic,heterogeneous nature of Edge computing in the Internet of Things(Edge-IoT)and Industrial IoT(IIoT)networks brings unique and evolving cybersecurity challenges.This study maps cyber threats in Edge-IoT/IIoT... The dynamic,heterogeneous nature of Edge computing in the Internet of Things(Edge-IoT)and Industrial IoT(IIoT)networks brings unique and evolving cybersecurity challenges.This study maps cyber threats in Edge-IoT/IIoT environments to the Adversarial Tactics,Techniques,and Common Knowledge(ATT&CK)framework by MITRE and introduces a lightweight,data-driven scoring model that enables rapid identification and prioritization of attacks.Inspired by the Factor Analysis of Information Risk model,our proposed scoring model integrates four key metrics:Common Vulnerability Scoring System(CVSS)-based severity scoring,Cyber Kill Chain–based difficulty estimation,Deep Neural Networks-driven detection scoring,and frequency analysis based on dataset prevalence.By aggregating these indicators,the model generates comprehensive risk profiles,facilitating actionable prioritization of threats.Robustness and stability of the scoring model are validated through non-parametric correlation analysis using Spearman’s and Kendall’s rank correlation coefficients,demonstrating consistent performance across diverse scenarios.The approach culminates in a prioritized attack ranking that provides actionable guidance for risk mitigation and resource allocation in Edge-IoT/IIoT security operations.By leveraging real-world data to align MITRE ATT&CK techniques with CVSS metrics,the framework offers a standardized and practically applicable solution for consistent threat assessment in operational settings.The proposed lightweight scoring model delivers rapid and reliable results under dynamic cyber conditions,facilitating timely identification of attack scenarios and prioritization of response strategies.Our systematic integration of established taxonomies with data-driven indicators strengthens practical risk management and supports strategic planning in next-generation IoT deployments.Ultimately,this work advances adaptive threat modeling for Edge/IIoT ecosystems and establishes a robust foundation for evidence-based prioritization in emerging cyber-physical infrastructures. 展开更多
关键词 MITRE ATT&CK edge environment IOT threat analysis quantitative analysis deep neural network CVSS risk assessment scoring model
在线阅读 下载PDF
Cryptocurrency Volatility and Its Impact on Emerging Markets: Quantitative Analysis
3
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
在线阅读 下载PDF
Quantitative Analysis of the Policy of Centralized Drug Procurement Based on PMC Index Model
4
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
暂未订购
Ultra-simplified design and quantitative analysis for the optical system of compact laser-induced breakdown spectroscopy
5
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
在线阅读 下载PDF
Four‐Dimensional Analysis of F‐18 Fluorodeoxyglucose Distribution
6
作者 Nagara Tamaki Tomoya Kotani +1 位作者 Yoshitomo Nakai Kei Yamada 《iRADIOLOGY》 2025年第5期330-336,共7页
Positron emission tomography(PET)with F‐18 fluorodeoxyglucose(FDG)is an established tool in clinical molecular imaging for evaluating metabolic activity.Advanced PET systems enable high‐resolution three‐dimensional... Positron emission tomography(PET)with F‐18 fluorodeoxyglucose(FDG)is an established tool in clinical molecular imaging for evaluating metabolic activity.Advanced PET systems enable high‐resolution three‐dimensional analysis of FDG distribution,offering insightful information for lesion characterization.Furthermore,dynamic whole‐body imaging facilitates assessment of temporal FDG uptake following its administration.This development introduces the concept of four‐dimensional(4D)FDG PET/CT,enhancing the precision of lesion characterization.A critical advantage of applying 4D FDG PET/CT is the ability to distinguish pathological from physiological FDG uptake by analyzing motion‐related uptake.Correcting motion and integrating serial imaging data enable accurate interpretation.Additionally,FDG uptake quantification is possible using Patlak analysis.This review discusses innovative clinical applications and quantitative techniques for analyzing FDG distribution through 4D FDG PET/CT. 展开更多
关键词 CANCER dynamic whole‐body imaging F‐18 fluorodeoxyglucose positron emission tomography quantitative analysis
暂未订购
Information mining and mechanical analysis of new-generation aero-engine turbine discs with industrial computed laminography reverse engineering
7
作者 Yenan GAO 《Chinese Journal of Aeronautics》 2025年第4期361-377,共17页
Aero engines are key power components that provide thrust for the aircraft.The cerme turbine disc allows the new-generation domestic fighter aircraft to increase the overall thrust of the aero engine.Quantifying coati... Aero engines are key power components that provide thrust for the aircraft.The cerme turbine disc allows the new-generation domestic fighter aircraft to increase the overall thrust of the aero engine.Quantifying coatings and analyzing the stress on the teeth play critical roles in improving the turbine disc’s performance,which are two issues must be solved urgently.First,this work pro poses a quantitative analysis algorithm to conduct the Three-Dimensional(3D)distribution informa tion mining of the extracted coatings.Then,it proposes an Industrial Computed Laminography(ICL)reconstruction algorithm for non-destructively reconstructing the turbine disc’s high-quality3D morphological actual feature.Finally,a Finite Element Analysis(FEA)under the ultimate thrus is conducted on ICL reconstruction to verify the working status of the new-generation aero-engine turbine disc.The results show that the proposed quantitative analysis algorithm digitizes the aggre gated conditions of the coating with a statistically normalized Z_(1)value of–2.15 and a confidence leve higher than 95%.Three image-quality quantitative indicators:Peak Signal-to-Noise Ratio(PSNR)Structural Similarity Index Measure(SSIM),and Normalized Mean Square Distance(NMSD)of the proposed ICL reconstruction algorithm on turbine disc laminographic image are 26.45,0.88,and 0.73respectively,which are better than other algorithms.The mechanical analysis of ICL more realisti cally reflects the stress and deformation than that of 3D modeling.This work provides new ideas for the iterative research of new-generation aero-engine turbine discs. 展开更多
关键词 Aero engines Quantitative analysis algorithm Information mining Industrial computed laminography reconstruction algorithm Finite element analysis
原文传递
Microscopic analysis of mechanical anisotropy and damage evolution of 3D printed rock-like samples under uniaxial compressive tests
8
作者 Yulong Shao Jingwei Yang +3 位作者 Jineon Kim Jae-Joon Song Juhyuk Moon Jianyong Han 《Journal of Rock Mechanics and Geotechnical Engineering》 2025年第2期688-704,共17页
Three-dimensional printing(3DP)offers valuable insight into the characterization of natural rocks and the verification of theoretical models due to its high reproducibility and accurate replication of complex defects ... Three-dimensional printing(3DP)offers valuable insight into the characterization of natural rocks and the verification of theoretical models due to its high reproducibility and accurate replication of complex defects such as cracks and pores.In this study,3DP gypsum samples with different printing directions were subjected to a series of uniaxial compression tests with in situ micro-computed tomography(micro-CT)scanning to quantitatively investigate their mechanical anisotropic properties and damage evolution characteristics.Based on the two-dimensional(2D)CT images obtained at different scanning steps,a novel void ratio variable was derived using the mean value and variance of CT intensity.Additionally,a constitutive model was formulated incorporating the proposed damage variable,utilizing the void ratio variable.The crack evolution and crack morphology of 3DP gypsum samples were obtained and analyzed using the 3D models reconstructed from the CT images.The results indicate that 3DP gypsum samples exhibit mechanical anisotropic characteristics similar to those found in naturally sedimentary rocks.The mechanical anisotropy is attributed to the bedding planes formed between adjacent layers and pillar-like structures along the printing direction formed by CaSO_(4)·2H_(2)O crystals of needle-like morphology.The mean gray intensity of the voids has a positive linear relationship with the threshold value,while the CT variance and void ratio have concave and convex relationships,respectively.The constitutive model can effectively match the stress–strain curves obtained from uniaxial compression experiments.This study provides comprehensive explanations of the failure modes and anisotropic mechanisms of 3DP gypsum samples,which is important for characterizing and understanding the failure mechanism and microstructural evolution of 3DP rocks when modeling natural rock behavior. 展开更多
关键词 Quantitative analysis Three-dimensional printing(3DP) Gypsum samples In situ micro-computed tomography(micro-CT)scanning Mechanical anisotropy Bedding planes Damage evolution
在线阅读 下载PDF
High-precision quantitative analysis of 3-nitro-1,2,4-triazol-5-one(NTO)concentration based on ATR-FTIR spectroscopy and machine learning
9
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
在线阅读 下载PDF
Qualitative and quantitative analysis of four different polarity fractions from Huang-Lian-Jie-Du-Decoction by HPLC-DAD-ESI-MS/MS and their related neuroprotective effects 被引量:6
10
作者 杨阳 赵海誉 +4 位作者 王宏洁 宋建芳 杨健 司南 边宝林 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2013年第4期334-341,共8页
Huang-Lian-Jie-Du-Decoction (HLJDD) has been widely used for the treatment of Alzheimer's disease (AD) in clinic. However, the relationship between its chemical profile and neuroprotective bioactivity was not cle... Huang-Lian-Jie-Du-Decoction (HLJDD) has been widely used for the treatment of Alzheimer's disease (AD) in clinic. However, the relationship between its chemical profile and neuroprotective bioactivity was not clearly clarified yet. In present study, the water extract of HLJDD and subsequent three polarity fractions divided by different reagents were investigated. A total of 17 chromatographic peaks were confirmed by comparison with standards and their UV, MS spectra. Among them, 11 major compounds were determined by HPLC-DAD method with good linear regression relationship (r2, 0.9994-0.9999), precisions (inter-day precision RSD, 0.79%-1.07%; intra-day precision RSD, 1.59%-2.10%), repeatability (RSD, 1.66%-3.67%), stability (RSD, 1.26%-4.77%) and recovery (95.24%-105.41%, RSD, 0.29%-2.69%). Furthermore, PC12 cells and primary neurons cells were used for the neuroprotective effective assessment of aforementioned four samples from HLJDD. 3"he total aqueous extract and n-butanol extract of HLJDD presented more significant effects than the other two parts. According to their quality and quantity determination results, iridoids and alkaloids have a positive correlation with the neuroprotective effectiveness of HLJDD. 展开更多
关键词 Huang-Lian-Jie-Du-Decoction Qualitative and quantitative analysis Neuroprotective effects
原文传递
Quantitative analysis of astragaloside IV in traditional Chinese medicine‘Huang-Qi-Si-Wu' Capsules by HPLC/UV 被引量:6
11
作者 张艳利 杨兴鑫 李晓妮 《Journal of Chinese Pharmaceutical Sciences》 CAS 2010年第3期223-228,共6页
A reliable and accurate HPLC/UV method was developed for the quantitative determination of astragaloside IV in 'Huang-Qi-Si-Wu' Capsules, a widely used prescription of traditional Chinese medicines (TCM). The chro... A reliable and accurate HPLC/UV method was developed for the quantitative determination of astragaloside IV in 'Huang-Qi-Si-Wu' Capsules, a widely used prescription of traditional Chinese medicines (TCM). The chromatographic separation conditions employed for HPLC/UV were optimized using a Hypersil-ODS column (250 mm^4.6 mm, 5.0 pm) with isocratic elution. Acetonitrile-water (32:68, v/v) were used as the mobile phase pumped at a flow rate of 1.0 mL/min and a detection wavelength at 203 nm was used. The method was fully validated with respect to linearity, precision, accuracy, specificity and robustness. The validated method was applied successfully to the quantification of astragaloside IV in the extract of 'Huang-Qi- Si-Wu' Capsules from different production batches. The results indicate that the established HPLC/UV method is suitable for the quantitative analysis and quality control of 'Huang-Qi-Si-Wu' Capsules and other related botanical drugs. 展开更多
关键词 HPLC/UV Quantitative analysis Astragaloside IV Radix Astragali 'Huang-Qi-Si-Wu' Capsules
原文传递
Design analysis and its application of M out of N in reactor protection system
12
作者 刘华 李军红 +1 位作者 文杰 阳武娇 《Journal of Measurement Science and Instrumentation》 CAS 2014年第3期60-63,共4页
The reliability and availability of the reactor protection system (RPS) can be improved by using M out of N judg- ment system. By analyzing two quantitative indicators, the rate of refusal to operate and mal-operati... The reliability and availability of the reactor protection system (RPS) can be improved by using M out of N judg- ment system. By analyzing two quantitative indicators, the rate of refusal to operate and mal-operation rate, a strict math- ematical formula and an approximate calculation are stated. The differences of a series of judgment systems are discussed on condition that the unsafe failure probability and the security failure probability are both 0.1. Based on given parameters (A, B,P, Q): A is upper limit of the refusal rate for the RPS, B is upper limit of the real-operation rate, P and Q are basic protection unit rates corresponding to refusal rate and mal-operation rate, respectively. According to these parameters, the values of N and M can be solved. 展开更多
关键词 reactor protection system (RPS) AVAILABILITY RELIABILITY M out of N system quantitative analysis
在线阅读 下载PDF
Qualitative and Quantitative Analysis of Alkaloids in Cortex Phellodendri by HPLC-ESI-MS/MS and HPLC-DAD 被引量:20
13
作者 ZHU Shuang-lai DOU Sheng-shan +6 位作者 LIU Xin-ru LIU Run-hui ZHANG Wei-dong HUANG Hong-lin ZHANG Yi HU Yao-hua WANG Shu-ping 《Chemical Research in Chinese Universities》 SCIE CAS CSCD 2011年第1期38-44,共7页
A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer(HPLC-ESI-MS/MS) coupled with a photodiode array detector(HPLC-DAD) and principal component analysis(PCA) was ... A combined method of high performance liquid chromatograph-elecrtrospray-ionization mass spectrometer(HPLC-ESI-MS/MS) coupled with a photodiode array detector(HPLC-DAD) and principal component analysis(PCA) was applied to the qualitative and quantitative analyses of alkaloids in Cortex Phellodendri(CP) samples, and to the differentiation of two species of CP, Cortex Phellodendri Chinensis(CPC) and Cortex Phellodendri Amurensis(CPA). Twenty-two peaks appeared in the HPLC-MS base peak chromatogram of CP detected by the HPLC-ESI-MS/MS analysis, and the alkaloids were identified according to the MSn data, the known MS fragmentation rules and the literature data. Five alkaloids including berberine, palmatine, jatrorrhizine, phellodendrine and magnoflorine were simultaneously determinated by the HPLC-DAD. Berberine was the primary component in all CP samples, and the contents of berberine and palmatine were exploited to be two critical parameters for effective discrimination between the two species of CP. The average content of berberine in CPC(58.75 mg/g) was higher than that in CPA(9.16 mg/g), while the content of palmatine was less, only 0.25 mg/g in CPC and 4.19 mg/g in CPA. With the use of PCA, samples datasets were separated successfully into two different clusters corresponding to the two species, and berberine, pahnatine, phellodendrine and magnoflorine contribute most to the above mentioned calssifying . The proposed method oroved to be a useful tool in the aualitv control of Chinese herbal medicines. 展开更多
关键词 Cortex Phellodendri ALKALOID HPLC-ESI-MS/MS Quantitative analysis Qualitative analysis Principal component analysis
在线阅读 下载PDF
Change of choline compounds in sodium selenite-induced apoptosis of rats used as quantitative analysis by in vitro 9.4T MR spectroscopy 被引量:14
14
作者 Zhen Cao Lin-Ping Wu +3 位作者 Yun-Xia Li Yu-Bo Guo Yao-Wen Chen Ren-Hua Wu 《World Journal of Gastroenterology》 SCIE CAS CSCD 2008年第24期3891-3896,共6页
AIM: To study liver cell apoptosis caused by the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy. METHODS: Twenty male Wistar ra... AIM: To study liver cell apoptosis caused by the toxicity of selenium and observe the alteration of choline compounds using in vitro 9.4T high resolution magnetic resonance spectroscopy. METHODS: Twenty male Wistar rats were randomly divided into two groups. The rats in the treatment group were intraperitoneally injected with sodium selenite and the control group with distilled water. All rats were sacrifi ced and the livers were dissected. 1H-MRS data were collected using in vitro 9.4T high resolution magnetic resonance spectrometer. Spectra were processed using XWINNMR and MestRe-c 4.3. HE and TUNEL staining was employed to detect and confi rm the change of liver cells. RESULTS: Good 1H-MR spectra of perchloric acid extract from liver tissue of rats were obtained. The conventional metabolites were detected and assigned. Concentrations of different ingredient choline compounds in treatment group vs control group were as follows: total choline compounds,5.08 ± 0.97 mmol/L vs 3.81 ± 1.16 mmol/L (P = 0.05); and free choline,1.07 ± 0.23 mmol/L vs 0.65 ± 0.20 mmol/L (P = 0.00). However,there was no statistical signif icance between the two groups. The hepatic sinus and cellular structure of hepatic cells in treatmentgroup were abnormal. Apoptosis of hepatic cells was confi rmed by TUNEL assay. CONCLUSION: High dose selenium compounds can cause the rat liver lesion and induce cell apoptosis in vivo. High resolution 1H-MRS in vitro can detect diversified metabolism. The changing trend for different ingredient of choline compounds is not completely the same at early period of apoptosis. 展开更多
关键词 Apoptosis of liver cell Choline compounds Sodium selenite In vitro ^1H-MRS Quantitative analysis
暂未订购
Analysis of abnormal texture formation and strengthening mechanism in an extruded Mg-Gd-Y-Zn-Zr alloy 被引量:13
15
作者 Xueze Jin Wenchen Xu +4 位作者 Zhongze Yang Can Yuan Debin Shan BugangTeng Bo Cheng Jin 《Journal of Materials Science & Technology》 SCIE EI CAS CSCD 2020年第10期133-145,共13页
A Mg-Gd-Y-Zn-Zr magnesium alloy with different initial states was extruded under different extrusion parameters.The effect of solution treatment and extrusion parameters on the microstructure,texture and mechanical pr... A Mg-Gd-Y-Zn-Zr magnesium alloy with different initial states was extruded under different extrusion parameters.The effect of solution treatment and extrusion parameters on the microstructure,texture and mechanical properties were analyzed in detail,and the abnormal texture formation and strengthening mechanism was revealed.When extruded at low temperature and small extrusion ratio,the bimodal microstructure consisting of fine dynamically recrystallized grains and coarse deformed grains occurred both in the as-cast alloy and solution-treated alloy.When the extrusion temperature and extrusion ratio were increased,the amount and size of dynamically recrystallized grains increased and the grain size of the solution-treated alloy showed higher growth rate.Furthermore,an abnormal texture with<0001>parallel with extrusion direction developed due to the occurrence of non-basal slip and continuous dynamic recrystallization.This could be enhanced by solution treatment,high temperature,and large extrusion ratio.Both the as-cast alloy and solution-treated alloy exhibited the highest tensile strength after extrusion at 300℃with an extrusion ratio of 9.Grain refinement was the main strengthening mechanism utilized in both the as-cast alloy and the solution-treated alloy.Work hardening played an important role in the sample extruded at low temperature and small extrusion ratio,with the highest contribution of about 33 MPa after extrusion at 300℃with an extrusion ratio of 9.Texture strengthening contributed more in the sample extruded at high temperature and large extrusion ratio,but no more than 24.1 MPa.Solution strengthening was another strengthening mechanism in the extruded as-cast alloy,especially at high temperature and large extrusion ratio(no more than 9 MPa). 展开更多
关键词 Hot extrusion Heat treatment Abnormal texture Strengthening mechanism Quantitative analysis
原文传递
Quantitative Analysis of Moisture Effect on Black Soil Reflectance 被引量:8
16
作者 LIU Huan-Jun ZHANG Yuan-Zhi +4 位作者 ZHANG Xin-Le ZHANG Bai SONG Kai-Shan WANG Zong-Ming TANG Na 《Pedosphere》 SCIE CAS CSCD 2009年第4期532-540,共9页
Several studies have demonstrated that soil reflectance decreases with increasing soil moisture content, or increases when the soil moisture reaches a certain content; however, there are few analyses on the quantitati... Several studies have demonstrated that soil reflectance decreases with increasing soil moisture content, or increases when the soil moisture reaches a certain content; however, there are few analyses on the quantitative relationship between soil reflectance and its moisture, especially in the case of black soils in northeast China. A new moisture adjusting method was developed to obtain soil reflectance with a smaller moisture interval to describe the quantitative relationship between soil reflectance and moisture. For the soil samples with moisture contents ranging from air-dry to saturated, the changes in soil reflectance with soil moisture can be depicted using a cubic equation. Both moisture threshold (MT) and moisture inflexion (MI) of soil reflectance can also be determined by the equation. When the moisture range was smaller than MT, soil reflectance can be simulated with a linear model. However, for samples with different soil organic matter (OM), the parameters of the linear model varied regularly with the OM content. Based on their relationship, the soil moisture can be estimated from soil reflectance in the black soil region. 展开更多
关键词 black soil quantitative analysis remote sensing soil moisture spectral reflectance
在线阅读 下载PDF
Texture features analysis on micro-structure of paste backfill based on image analysis technology 被引量:8
17
作者 YIN Sheng-hua SHAO Ya-jian +2 位作者 WU Ai-xiang WANG Yi-ming GAO Zhi-yong 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第10期2360-2372,共13页
The strength of cement-based materials,such as mortar,concrete and cement paste backfill(CPB),depends on its microstructures(e.g.pore structure and arrangement of particles and skeleton).Numerous studies on the relati... The strength of cement-based materials,such as mortar,concrete and cement paste backfill(CPB),depends on its microstructures(e.g.pore structure and arrangement of particles and skeleton).Numerous studies on the relationship between strength and pore structure(e.g.,pore size and its distribution)were performed,but the micro-morphology characteristics have been rarely concerned.Texture describing the surface properties of the sample is a global feature,which is an effective way to quantify the micro-morphological properties.In statistical analysis,GLCM features and Tamura texture are the most representative methods for characterizing the texture features.The mechanical strength and section image of the backfill sample prepared from three different solid concentrations of paste were obtained by uniaxial compressive strength test and scanning electron microscope,respectively.The texture features of different SEM images were calculated based on image analysis technology,and then the correlation between these parameters and the strength was analyzed.It was proved that the method is effective in the quantitative analysis on the micro-morphology characteristics of CPB.There is a significant correlation between the texture features and the unconfined compressive strength,and the prediction of strength is feasible using texture parameters of the CPB microstructure. 展开更多
关键词 microstructure texture feature Tamura texture GLCM feature unconfined compressive strength quantitative analysis cement paste backfill
在线阅读 下载PDF
Simultaneous determination of five phenylethanoid glycosides in Cistanches Herba using quantitative analysis of multi-components by single marker 被引量:10
18
作者 Ruiyan Li Mingbo Zhao +1 位作者 Pengfei Tu Yong Jiang 《Journal of Chinese Pharmaceutical Sciences》 CAS CSCD 2019年第8期537-546,共10页
In the present study, a method for the quantitative analysis of multi-components by single marker(QAMS) has been developed and validated for the simultaneous determination of echinacoside(ECH), tubuloside A, acteoside... In the present study, a method for the quantitative analysis of multi-components by single marker(QAMS) has been developed and validated for the simultaneous determination of echinacoside(ECH), tubuloside A, acteoside, isoacteoside, and2’-acetylacteoside in Cistanches Herba. ECH was used as the internal standard(IS) to obtain the relative correction factors(RCFs) of the other four phenylethanoid glycosides(PhGs);meanwhile, various influencing factors on RCFs were investigated under different conditions. The content of each component was calculated with RCF. The results were compared with those obtained by the external standard method(ESM) to verify the feasibility and accuracy of the established QAMS method. No significant difference was found in the quantitative results of 10 batches of Cistanches Herba between QAMS and ESM. The proposed QAMS method for simultaneous determination of PhGs in Cistanches Herba is accurate and feasible, providing an efficient and economical approach for the quality control of Cistanches Herba. 展开更多
关键词 Cistanches Herba Phenylethanoid glycosides Quantitative analysis of multi-components by single-marker Relative correction factors
原文传递
Quantitative analysis of the impact factors of conventional energy carbon emissions in Kazakhstan based on LMDI decomposition and STIRPAT model 被引量:7
19
作者 李佳秀 陈亚宁 +1 位作者 李稚 刘志辉 《Journal of Geographical Sciences》 SCIE CSCD 2018年第7期1001-1019,共19页
Quantitative analysis of the impact factors in energy-related CO2 emissions serves as an important guide for reducing carbon emissions and building an environmentally-friendly society. This paper aims to use LMDI meth... Quantitative analysis of the impact factors in energy-related CO2 emissions serves as an important guide for reducing carbon emissions and building an environmentally-friendly society. This paper aims to use LMDI method and a modified STIRPAT model to research the conventional energy-related CO_2 emissions in Kazakhstan after the collapse of the Soviet Union. The results show that the trajectory of CO2 emissions displayed U-shaped curve from 1992 to 2013. Based on the extended Kaya identity and additive LMDI method, we decomposed total CO2 emissions into four influencing factors. Of those, the economic active effect is the most influential factor driving CO2 emissions, which produced 110.86 Mt CO2 emissions, with a contribution rate of 43.92%. The second driving factor is the population effect, which led to 11.87 Mt CO2 emissions with a contribution rate of 4.7%. On the contrary, the energy intensity effect is the most inhibiting factor, which caused –110.90 Mt CO2 emissions with a contribution rate of –43.94%, followed by the energy carbon structure effect resulting in –18.76 Mt CO2 emissions with a contribution rate of –7.43%. In order to provide an in-depth examination of the change response between energy-related CO2 emissions and each impact factor, we construct a modified STIRPAT model based on ridge regression estimation. The results indicate that for every 1% increase in population size, economic activity, energy intensity and energy carbon structure, there is a subsequent increase in CO_2 emissions of 3.13%, 0.41%, 0.30% and 0.63%, respectively. 展开更多
关键词 quantitative analysis energy-related C02 emissions STIRPAT model Kazakhstan
原文传递
Calculation of Ecological Footprint Based on Modified Method and Quantitative Analysis of Its Impact Factors——A Case Study of Shanghai 被引量:4
20
作者 GAO Chengkang JIANG Dahe +1 位作者 WANG Dan YAN Jonathan 《Chinese Geographical Science》 SCIE CSCD 2006年第4期306-313,共8页
Ecological footprint (EF) has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some... Ecological footprint (EF) has attracted much attention internationally as a potential indicator for sustainable development. In China, EF has also gained recognition in related fields and disciplines. Moreover, some scholars in these fields have proposed alternative methods to calculate EF and have made some progress. This paper, therefore, begins with the introduction and development of EF in China. However, the established methods of EF calculation hold some limitations, such as indicator variance and result abnormality. In order to resolve those problems, the authors make a further modification considering the demand of EF as a comprehensive indicator: 1) More accurate analysis has been done to divide EF into several parts: imported EF, exported EF, and producible EF, which is the solution to the problem of abnormality in original EF results and can explain abnormal phenomena reasonably. 2) Considering the actual situa- tion of Shanghai, emended equivalence factor is brought forward and a matrix is formed with equivalence factors. The measure can reduce the deviation between the fact and the results. 3) The calculation compares local yield with global average yield to analyze the effects of yields. And based on local yields in different years, the results are more accurate. Finally, the calculation method is applied to calculating EF of Shanghai from 1980 to 2003, and the subsequent detailed analysis is presented. Available data and results suggest a statistically significant correlation coefficient between EF and GDP, population density and urbaniTation level. Through analyzing the process of calculating EF and its results, it can be seen that EF, as a macro-indicator, can not exactly indicate whether development within a region can meet the re- quests of sustainable development, which can be explained by the fact that the result of EF is impacted greatly by sub- jective factors including national policy,available technology, population, etc. Nevertheless, EF can demonstrate, at least to some degree, the regional status in terms of resources and energy consumption, as well as developmental potential. The calculation of EF, therefore, deserves further research to achieve more far-reaching significance in application. 展开更多
关键词 ecological footprint quantitative analysis impact factors SHANGHAI
在线阅读 下载PDF
上一页 1 2 15 下一页 到第
使用帮助 返回顶部