Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic grap...Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.展开更多
Software projects are becoming larger and more complicated. Managing those projects is based on several software development methodologies. One of those methodologies is software version control, which is used in the ...Software projects are becoming larger and more complicated. Managing those projects is based on several software development methodologies. One of those methodologies is software version control, which is used in the majority of worldwide software projects. Although existing version control systems provide sufficient functionality in many situations, they are lacking in terms of semantics and structure for source code. It is commonly believed that improving software version control can contribute substantially to the development of software. We present a solution that considers a structural model for matching source code that can be used in version control.展开更多
A version of a product consists of the product structure tree and the versions of all its components. The model includes two sets of data: attributes and documents describing each component. The paper discusses the v...A version of a product consists of the product structure tree and the versions of all its components. The model includes two sets of data: attributes and documents describing each component. The paper discusses the version change relations between a sub-node component and a up-node component in a product structure tree, analyzes the version control system for a static reference and that for a dynamic reference and proposes a product structure model in support of dynamic reference, which is easy to use and contains a complete set of information providing an essential way of data organization for the PDM system.展开更多
By comparing China's import of major imported agriculture textile material( cotton and wool),the characteristics of import are concluded. On this basis,a restricted version of source differentiated almost ideal de...By comparing China's import of major imported agriculture textile material( cotton and wool),the characteristics of import are concluded. On this basis,a restricted version of source differentiated almost ideal demand system( RSDAIDS) is used to estimate the income and price elasticity of major imported agriculture textile material from the major sources based on the data from 1992 to 2015. The results are shown as follows.( 1) Although the dependency on imported cotton is lower than wool, the fluctuation of cotton import is much more drastic; China's demand for cotton is relatively price elastic with higher expenditure elasticity compared with wool; besides,the existence of complementarity is proved between imported cotton and wool.( 2) According to the import elasticity of cotton,demand for cotton imported from India shows priority over cotton from other sources; demand for cotton imported from America is the most price-sensitive one; substitution among cotton from different sources is weak.( 3) According to the import elasticity of wool,wool imported from Uruguay has bright market prospects. In addition,wool imported from Australia has irreplaceable advantage than that from New Zealand.展开更多
This paper applies PEST analysis to The Chinese Version of TikTok,a video-sharing app developed by Zhang Yiming and founded in 2016.It examines how TikTok has adapted to different market conditions over time using PES...This paper applies PEST analysis to The Chinese Version of TikTok,a video-sharing app developed by Zhang Yiming and founded in 2016.It examines how TikTok has adapted to different market conditions over time using PEST and SWOT analyses.This paper will provide critical insights into how The Chinese Version of TikTok has developed from the perspective of the company’s top management team in light of changes within the market since its establishment to help them make decisions about their strategy going forward.It will also look at changes in social behavior over time to explain their resilience.The PEST study of The Chinese Version of TikTok reveals that the political paradigm of the technical element,which includes the AI big data algorithms and the AI economic calculation model,can stimulate public interest because it is a content platform.As a result of its monopolistic nature,however,it is motivated by a desire to serve the public interest.We can see the opportunities that arise from these problems,but the benefits of technological advances are less noticeable.According to the SWOT analysis,five main advantages stem from the technical aspects.First,it has a vast user volume,which means it has acquired many data on user behavior.Second,it has powerful Big Data-based financial debugging skills.Third,it has access to cutting-edge artificial intelligence tools and data.In the fourth place,it has created an advertiser-friendly platform.As the last step,it has established a public service-oriented website.Because it relies on Big Data,AI’s technical flaws-including its flawed big data algorithms and extremely conservative economic calculating model-are greatly relieved because it relies on Big Data.Business choices under a centralized economic paradigm have to be made at the top,reducing room for creativity.Another flaw is that there is no internal mechanism for The Chinese Version of TikTok to adapt to changing circumstances or industry trends.The AI big data algorithms and the AI economic calculation model face competition from other participants in this industry who may have access to a more comprehensive database and superior artificial intelligence equipment.展开更多
Objective:The objective of the study is to validate the short version of evidence-based practice(EBP)instruments among nurses in clinical practice.Methods:An institutional-based cross-sectional research design was use...Objective:The objective of the study is to validate the short version of evidence-based practice(EBP)instruments among nurses in clinical practice.Methods:An institutional-based cross-sectional research design was used and a stratified sampling technique to select 285 nurse clinicians.The study utilized a structured questionnaire comprising of demographic data from the participants and three validated scales:the shortened versions of the EBP Beliefs Scale,the EBP Implementation Scale,and the Organizational Culture and Readiness for System-Wide Integration of Evidence-Based Practice(OCRSIEP)survey.With the use of descriptive statistics,the data were analyzed and presented in frequencies and percentages,while inter-item correlation coefficient(ICC)and the Kaiser-Meyer-Olkin measure of sampling adequacy were used to confirm the validity of using factor analysis.Results:Findings revealed the mean scores of the EBP Beliefs Scale ranged from 1.50 to 1.61,EBP Implementation Scale ranged from 1.84 to 1.94,and the OCRSIEP Scale ranged from 1.93 to 2.19.All the three shortened scales accordingly had good internal reliability,29.30±9.93 out of 80 for the EBP Beliefs Scale,19.56±7.37 out of 72 for the EBP Implementation Scale,and 66.32±20.35 out of 125 for the OCRSIEP Scale.Conclusion:This study has generated a valid Short Version of EBP reliable instrument that is psychometrically robust that can be used by nurses and clinicians to evaluate EBP in clinical settings since the results presented as a whole confirmed the high reliability and factorial validity.展开更多
Lu Xun(1881-1936)has been acclaimed father of modern Chinese literature.He is the first writer to use the vernacular to write fiction.His stories have laid a solid foundation for the development of modern Chinese fict...Lu Xun(1881-1936)has been acclaimed father of modern Chinese literature.He is the first writer to use the vernacular to write fiction.His stories have laid a solid foundation for the development of modern Chinese fiction.Call to Arms(1923)and Wandering(1926)represent the greatest achievement of Chinese story-writing at that time.Since the 1920’s,Lu Xun’s stories have been translated into various languages and published throughout the world,enjoying an international reputation.The three English versions chosen are different with various features,especially in dealing with Chinese traditional culture according to different purposes and towards different English readers.展开更多
Lu Xun(1881-1936)has been acclaimed father of modern Chinese literature.He is the first writer to use the vernacular to write fiction.His stories have laid a solid foundation for the development of modern Chinese fict...Lu Xun(1881-1936)has been acclaimed father of modern Chinese literature.He is the first writer to use the vernacular to write fiction.His stories have laid a solid foundation for the development of modern Chinese fiction.Call to Arms(1923)and Wandering(1926)represent the greatest achievement of Chinese story-writing at that time.His short stories are not only profound in thinking,but also worthy of admiration for their great value and innovation in art.Since the 1920’s,Lu Xun’s stories have been translated into various languages and published throughout the world,enjoying an international reputation.Only their English versions in the 20th century are discussed within this paper.These versions are different with various features,especially in dealing with Chinese traditional culture according to different purposes and towards different English readers.展开更多
针对无人机航拍图像目标检测中视野变化大、时空信息复杂等问题,文中基于YOLOv5(You Only Look Once Version5)架构,提出基于图像低维特征融合的航拍小目标检测模型.引入CA(Coordinate Attention),改进MobileNetV3的反转残差块,增加图...针对无人机航拍图像目标检测中视野变化大、时空信息复杂等问题,文中基于YOLOv5(You Only Look Once Version5)架构,提出基于图像低维特征融合的航拍小目标检测模型.引入CA(Coordinate Attention),改进MobileNetV3的反转残差块,增加图像空间维度信息的同时降低模型参数量.改进YOLOv5特征金字塔网络结构,融合浅层网络中的特征图,增加模型对图像低维有效信息的表达能力,进而提升小目标检测精度.同时为了降低航拍图像中复杂背景带来的干扰,引入无参平均注意力模块,同时关注图像的空间注意力与通道注意力;引入VariFocal Loss,降低负样本在训练过程中的权重占比.在VisDrone数据集上的实验验证文中模型的有效性,该模型在有效提升检测精度的同时明显降低复杂度.展开更多
Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually app...Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually applied. Purpose: To compare the correction effects of the phased-array uniformity enhancement (PURE), a calibration-based image non-uniformity correction method, among three different software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Material and Methods: Hepatobiliary-phase images of a total of 120 patients who underwent Gd-EOB-DTPA-enhanced MR imaging on the same 3T scanner were analyzed retrospectively. Forty patients each were examined using three software versions (DV25, DV25.1, and DV26). The effects of PURE were compared by visual assessment, histogram analysis of liver signal intensity, evaluation of the spatial distribution of correction effects, and evaluation of quantitative indices of liver parenchymal enhancement. Results: The visual assessment indicated the highest uniformity of PURE-corrected images for DV26, followed by DV25 and DV25.1. Histogram analysis of corrected images demonstrated significantly larger variations in liver signal for DV25.1 than for the other two versions. Although PURE caused a relative increase in pixel values for central and lateral regions, such effects were weaker for DV25.1 than for the other two versions. In the evaluation of quantitative indices of liver parenchymal enhancement, the liver-to-muscle ratio (LMR) was significantly higher for the corrected images than for the uncorrected images, but the liver-to-spleen ratio (LSR) showed no significant differences. For corrected images, the LMR was significantly higher for DV25 and DV26 than for DV25.1, but the LSR showed no significant differences among the three versions. Conclusion: There were differences in the effects of PURE among the three software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Even if the non-uniformity correction method has the same brand name, correction effects may differ depending on the software version, and these differences may affect visual and quantitative evaluations.展开更多
Vapor pressure deficit(VPD)plays a crucial role in determining plant physiological functions and exerts a substantial influence on vegetation,second only to carbon dioxide(CO_(2)).As a robust indicator of atmospheric ...Vapor pressure deficit(VPD)plays a crucial role in determining plant physiological functions and exerts a substantial influence on vegetation,second only to carbon dioxide(CO_(2)).As a robust indicator of atmospheric water demand,VPD has implications for global water resources,and its significance extends to the structure and functioning of ecosystems.However,the influence of VPD on vegetation growth under climate change remains unclear in China.This study employed empirical equations to estimate the VPD in China from 2000 to 2020 based on meteorological reanalysis data of the Climatic Research Unit(CRU)Time-Series version 4.06(TS4.06)and European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA-5).Vegetation growth status was characterized using three vegetation indices,namely gross primary productivity(GPP),leaf area index(LAI),and near-infrared reflectance of vegetation(NIRv).The spatiotemporal dynamics of VPD and vegetation indices were analyzed using the Theil-Sen median trend analysis and Mann-Kendall test.Furthermore,the influence of VPD on vegetation growth and its relative contribution were assessed using a multiple linear regression model.The results indicated an overall negative correlation between VPD and vegetation indices.Three VPD intervals for the correlations between VPD and vegetation indices were identified:a significant positive correlation at VPD below 4.820 hPa,a significant negative correlation at VPD within 4.820–9.000 hPa,and a notable weakening of negative correlation at VPD above 9.000 hPa.VPD exhibited a pronounced negative impact on vegetation growth,surpassing those of temperature,precipitation,and solar radiation in absolute magnitude.CO_(2) contributed most positively to vegetation growth,with VPD offsetting approximately 30.00%of the positive effect of CO_(2).As the rise of VPD decelerated,its relative contribution to vegetation growth diminished.Additionally,the intensification of spatial variations in temperature and precipitation accentuated the spatial heterogeneity in the impact of VPD on vegetation growth in China.This research provides a theoretical foundation for addressing climate change in China,especially regarding the challenges posed by increasing VPD.展开更多
China’s unconventional gas fields have a large number of low-productivity and low-efficiency wells, many of whichare located in remote and environmentally harsh mountainous areas. To address the long-term stable prod...China’s unconventional gas fields have a large number of low-productivity and low-efficiency wells, many of whichare located in remote and environmentally harsh mountainous areas. To address the long-term stable productionof these gas wells, plunger-lift technology plays an important role. In order to fully understand and accurately graspthe drainage and gas production mechanisms of plunger-lift, a mechanical model of plunger-liquid column uplift inthe plunger-lift process was established, focusing on conventional plunger-lift systems and representative wellboreconfigurations in the Linxing region. The operating casing pressure of the plunger-lift process and the calculationmethod for the maximum daily fluid production rate based on the work regime with the highest fluid recovery ratewere determined. For the first time, the critical flow rate method was proposed as a constraint for the maximumliquid-carrying capacity of the plunger-lift, and liquid-carrying capacity charts for conventional plunger-lift withdifferent casing sizes were developed. The results showed that for 23/8 casing plunger-lift, with a well depth ofshallower than 808 m, the maximum drainage rate was 33 m3/d;for 27/8 casing plunger-lift, with a well depth ofshallower than 742 m, the maximum drainage rate was 50.15 m3/d;for 31/2 casing plunger-lift, with a well depthof shallower than 560 m, the maximum drainage rate was 75.14 m3/d. This research provides a foundation for thescientific selection of plunger-lift technology and serves as a decision-making reference for developing reasonableplunger-lift work regimes.展开更多
Drone or unmanned aerial vehicle(UAV)technology has undergone significant changes.The technology allows UAV to carry out a wide range of tasks with an increasing level of sophistication,since drones can cover a large ...Drone or unmanned aerial vehicle(UAV)technology has undergone significant changes.The technology allows UAV to carry out a wide range of tasks with an increasing level of sophistication,since drones can cover a large area with cameras.Meanwhile,the increasing number of computer vision applications utilizing deep learning provides a unique insight into such applications.The primary target in UAV-based detection applications is humans,yet aerial recordings are not included in the massive datasets used to train object detectors,which makes it necessary to gather the model data from such platforms.You only look once(YOLO)version 4,RetinaNet,faster region-based convolutional neural network(R-CNN),and cascade R-CNN are several well-known detectors that have been studied in the past using a variety of datasets to replicate rescue scenes.Here,we used the search and rescue(SAR)dataset to train the you only look once version 5(YOLOv5)algorithm to validate its speed,accuracy,and low false detection rate.In comparison to YOLOv4 and R-CNN,the highest mean average accuracy of 96.9%is obtained by YOLOv5.For comparison,experimental findings utilizing the SAR and the human rescue imaging database on land(HERIDAL)datasets are presented.The results show that the YOLOv5-based approach is the most successful human detection model for SAR missions.展开更多
[Objectives]This study aimed to investigate the incidence and risk factors associated with SSD in patients following cardiac surgery.[Methods]A total of 378 patients who underwent cardiac surgery in Taihe Hospital wer...[Objectives]This study aimed to investigate the incidence and risk factors associated with SSD in patients following cardiac surgery.[Methods]A total of 378 patients who underwent cardiac surgery in Taihe Hospital were recruited and screened.Diagnosis of delirium was made using evaluation methods and DSM-5 criteria.SSD was defined as the presence of one or more core features of delirium without meeting the full diagnostic criteria.Statistical analysis included independent samples t-test for group comparisons and binary logistic regression analysis to identify independent risk factors for SSD after cardiac surgery.[Results]Among the 378 subjects,112(29.63%)had SSD,28(7.41%)had delirium,and the remaining 238 patients(62.96%)did not present with delirium.Univariate analysis revealed that age,APACHE II score,duration of aortic clamping,length of ICU stay,duration of sedation use,and daily sleep time were significant risk factors for the occurrence of SSD(P<0.05).Logistic regression analysis identified age>70 years old,APACHE II score>20 points,length of ICU stay>5 d,and duration of sedation use>24 h as independent risk factors for SSD after cardiac surgery(P<0.05).A functional model was fitted based on the analysis results of the binary logistic regression model,yielding the equation logit P=1.472X_(1)+2.213X_(2)+3.028X_(3)+1.306X_(4).[Conclusions]Comprehensive clinical assessment is crucial for patients undergoing cardiac surgery,and appropriate preventive measures should be taken for patients with identified risk factors.Close monitoring of the patient s consciousness should be implemented postoperatively,and timely interventions should be conducted.Further research should focus on model validation and optimization.展开更多
基金the Scientific Technology Development Project of Heilongjiang(Grant No.WH05A01 and GB05A103)Scientific Technology Development Project of Harbin
文摘Based on the key function of version management in PDM system, this paper discusses the function and the realization of version management and the transitions of version states with a workflow. A directed aeyclic graph is used to describe a version model. Three storage modes of the directed acyelic graph version model in the database, the bumping block and the PDM working memory are presented and the conversion principle of these three modes is given. The study indicates that building a dynamic product structure configuration model based on versions is the key to resolve the problem. Thus a version model of single product object is built. Then the version management model in product structure configuration is built and the application of version management of PDM syster is presented as a case.
文摘Software projects are becoming larger and more complicated. Managing those projects is based on several software development methodologies. One of those methodologies is software version control, which is used in the majority of worldwide software projects. Although existing version control systems provide sufficient functionality in many situations, they are lacking in terms of semantics and structure for source code. It is commonly believed that improving software version control can contribute substantially to the development of software. We present a solution that considers a structural model for matching source code that can be used in version control.
基金Supported by the Fundamental Fujian Nature Science (A0440006) and Xiamen Science & Technology Project (3502Z20055028)
文摘A version of a product consists of the product structure tree and the versions of all its components. The model includes two sets of data: attributes and documents describing each component. The paper discusses the version change relations between a sub-node component and a up-node component in a product structure tree, analyzes the version control system for a static reference and that for a dynamic reference and proposes a product structure model in support of dynamic reference, which is easy to use and contains a complete set of information providing an essential way of data organization for the PDM system.
基金Industrial Research of National Wool and Csahmere Industry Technology System,China(No.CARS-40-20)
文摘By comparing China's import of major imported agriculture textile material( cotton and wool),the characteristics of import are concluded. On this basis,a restricted version of source differentiated almost ideal demand system( RSDAIDS) is used to estimate the income and price elasticity of major imported agriculture textile material from the major sources based on the data from 1992 to 2015. The results are shown as follows.( 1) Although the dependency on imported cotton is lower than wool, the fluctuation of cotton import is much more drastic; China's demand for cotton is relatively price elastic with higher expenditure elasticity compared with wool; besides,the existence of complementarity is proved between imported cotton and wool.( 2) According to the import elasticity of cotton,demand for cotton imported from India shows priority over cotton from other sources; demand for cotton imported from America is the most price-sensitive one; substitution among cotton from different sources is weak.( 3) According to the import elasticity of wool,wool imported from Uruguay has bright market prospects. In addition,wool imported from Australia has irreplaceable advantage than that from New Zealand.
文摘This paper applies PEST analysis to The Chinese Version of TikTok,a video-sharing app developed by Zhang Yiming and founded in 2016.It examines how TikTok has adapted to different market conditions over time using PEST and SWOT analyses.This paper will provide critical insights into how The Chinese Version of TikTok has developed from the perspective of the company’s top management team in light of changes within the market since its establishment to help them make decisions about their strategy going forward.It will also look at changes in social behavior over time to explain their resilience.The PEST study of The Chinese Version of TikTok reveals that the political paradigm of the technical element,which includes the AI big data algorithms and the AI economic calculation model,can stimulate public interest because it is a content platform.As a result of its monopolistic nature,however,it is motivated by a desire to serve the public interest.We can see the opportunities that arise from these problems,but the benefits of technological advances are less noticeable.According to the SWOT analysis,five main advantages stem from the technical aspects.First,it has a vast user volume,which means it has acquired many data on user behavior.Second,it has powerful Big Data-based financial debugging skills.Third,it has access to cutting-edge artificial intelligence tools and data.In the fourth place,it has created an advertiser-friendly platform.As the last step,it has established a public service-oriented website.Because it relies on Big Data,AI’s technical flaws-including its flawed big data algorithms and extremely conservative economic calculating model-are greatly relieved because it relies on Big Data.Business choices under a centralized economic paradigm have to be made at the top,reducing room for creativity.Another flaw is that there is no internal mechanism for The Chinese Version of TikTok to adapt to changing circumstances or industry trends.The AI big data algorithms and the AI economic calculation model face competition from other participants in this industry who may have access to a more comprehensive database and superior artificial intelligence equipment.
文摘Objective:The objective of the study is to validate the short version of evidence-based practice(EBP)instruments among nurses in clinical practice.Methods:An institutional-based cross-sectional research design was used and a stratified sampling technique to select 285 nurse clinicians.The study utilized a structured questionnaire comprising of demographic data from the participants and three validated scales:the shortened versions of the EBP Beliefs Scale,the EBP Implementation Scale,and the Organizational Culture and Readiness for System-Wide Integration of Evidence-Based Practice(OCRSIEP)survey.With the use of descriptive statistics,the data were analyzed and presented in frequencies and percentages,while inter-item correlation coefficient(ICC)and the Kaiser-Meyer-Olkin measure of sampling adequacy were used to confirm the validity of using factor analysis.Results:Findings revealed the mean scores of the EBP Beliefs Scale ranged from 1.50 to 1.61,EBP Implementation Scale ranged from 1.84 to 1.94,and the OCRSIEP Scale ranged from 1.93 to 2.19.All the three shortened scales accordingly had good internal reliability,29.30±9.93 out of 80 for the EBP Beliefs Scale,19.56±7.37 out of 72 for the EBP Implementation Scale,and 66.32±20.35 out of 125 for the OCRSIEP Scale.Conclusion:This study has generated a valid Short Version of EBP reliable instrument that is psychometrically robust that can be used by nurses and clinicians to evaluate EBP in clinical settings since the results presented as a whole confirmed the high reliability and factorial validity.
文摘Lu Xun(1881-1936)has been acclaimed father of modern Chinese literature.He is the first writer to use the vernacular to write fiction.His stories have laid a solid foundation for the development of modern Chinese fiction.Call to Arms(1923)and Wandering(1926)represent the greatest achievement of Chinese story-writing at that time.Since the 1920’s,Lu Xun’s stories have been translated into various languages and published throughout the world,enjoying an international reputation.The three English versions chosen are different with various features,especially in dealing with Chinese traditional culture according to different purposes and towards different English readers.
文摘Lu Xun(1881-1936)has been acclaimed father of modern Chinese literature.He is the first writer to use the vernacular to write fiction.His stories have laid a solid foundation for the development of modern Chinese fiction.Call to Arms(1923)and Wandering(1926)represent the greatest achievement of Chinese story-writing at that time.His short stories are not only profound in thinking,but also worthy of admiration for their great value and innovation in art.Since the 1920’s,Lu Xun’s stories have been translated into various languages and published throughout the world,enjoying an international reputation.Only their English versions in the 20th century are discussed within this paper.These versions are different with various features,especially in dealing with Chinese traditional culture according to different purposes and towards different English readers.
文摘针对无人机航拍图像目标检测中视野变化大、时空信息复杂等问题,文中基于YOLOv5(You Only Look Once Version5)架构,提出基于图像低维特征融合的航拍小目标检测模型.引入CA(Coordinate Attention),改进MobileNetV3的反转残差块,增加图像空间维度信息的同时降低模型参数量.改进YOLOv5特征金字塔网络结构,融合浅层网络中的特征图,增加模型对图像低维有效信息的表达能力,进而提升小目标检测精度.同时为了降低航拍图像中复杂背景带来的干扰,引入无参平均注意力模块,同时关注图像的空间注意力与通道注意力;引入VariFocal Loss,降低负样本在训练过程中的权重占比.在VisDrone数据集上的实验验证文中模型的有效性,该模型在有效提升检测精度的同时明显降低复杂度.
文摘Background: Non-uniformity in signal intensity occurs commonly in magnetic resonance (MR) imaging, which may pose substantial problems when using a 3T scanner. Therefore, image non-uniformity correction is usually applied. Purpose: To compare the correction effects of the phased-array uniformity enhancement (PURE), a calibration-based image non-uniformity correction method, among three different software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Material and Methods: Hepatobiliary-phase images of a total of 120 patients who underwent Gd-EOB-DTPA-enhanced MR imaging on the same 3T scanner were analyzed retrospectively. Forty patients each were examined using three software versions (DV25, DV25.1, and DV26). The effects of PURE were compared by visual assessment, histogram analysis of liver signal intensity, evaluation of the spatial distribution of correction effects, and evaluation of quantitative indices of liver parenchymal enhancement. Results: The visual assessment indicated the highest uniformity of PURE-corrected images for DV26, followed by DV25 and DV25.1. Histogram analysis of corrected images demonstrated significantly larger variations in liver signal for DV25.1 than for the other two versions. Although PURE caused a relative increase in pixel values for central and lateral regions, such effects were weaker for DV25.1 than for the other two versions. In the evaluation of quantitative indices of liver parenchymal enhancement, the liver-to-muscle ratio (LMR) was significantly higher for the corrected images than for the uncorrected images, but the liver-to-spleen ratio (LSR) showed no significant differences. For corrected images, the LMR was significantly higher for DV25 and DV26 than for DV25.1, but the LSR showed no significant differences among the three versions. Conclusion: There were differences in the effects of PURE among the three software versions in 3T Gd-EOB-DTPA-enhanced MR imaging. Even if the non-uniformity correction method has the same brand name, correction effects may differ depending on the software version, and these differences may affect visual and quantitative evaluations.
基金This research was supported by the National Natural Science Foundation of China(42161058).
文摘Vapor pressure deficit(VPD)plays a crucial role in determining plant physiological functions and exerts a substantial influence on vegetation,second only to carbon dioxide(CO_(2)).As a robust indicator of atmospheric water demand,VPD has implications for global water resources,and its significance extends to the structure and functioning of ecosystems.However,the influence of VPD on vegetation growth under climate change remains unclear in China.This study employed empirical equations to estimate the VPD in China from 2000 to 2020 based on meteorological reanalysis data of the Climatic Research Unit(CRU)Time-Series version 4.06(TS4.06)and European Centre for Medium-Range Weather Forecasts(ECMWF)Reanalysis 5(ERA-5).Vegetation growth status was characterized using three vegetation indices,namely gross primary productivity(GPP),leaf area index(LAI),and near-infrared reflectance of vegetation(NIRv).The spatiotemporal dynamics of VPD and vegetation indices were analyzed using the Theil-Sen median trend analysis and Mann-Kendall test.Furthermore,the influence of VPD on vegetation growth and its relative contribution were assessed using a multiple linear regression model.The results indicated an overall negative correlation between VPD and vegetation indices.Three VPD intervals for the correlations between VPD and vegetation indices were identified:a significant positive correlation at VPD below 4.820 hPa,a significant negative correlation at VPD within 4.820–9.000 hPa,and a notable weakening of negative correlation at VPD above 9.000 hPa.VPD exhibited a pronounced negative impact on vegetation growth,surpassing those of temperature,precipitation,and solar radiation in absolute magnitude.CO_(2) contributed most positively to vegetation growth,with VPD offsetting approximately 30.00%of the positive effect of CO_(2).As the rise of VPD decelerated,its relative contribution to vegetation growth diminished.Additionally,the intensification of spatial variations in temperature and precipitation accentuated the spatial heterogeneity in the impact of VPD on vegetation growth in China.This research provides a theoretical foundation for addressing climate change in China,especially regarding the challenges posed by increasing VPD.
基金the Fundamental Research Funds for the Central Universities of China(No.20CX02308A)CNOOC Project(No.ZX2022ZCCYF3835).
文摘China’s unconventional gas fields have a large number of low-productivity and low-efficiency wells, many of whichare located in remote and environmentally harsh mountainous areas. To address the long-term stable productionof these gas wells, plunger-lift technology plays an important role. In order to fully understand and accurately graspthe drainage and gas production mechanisms of plunger-lift, a mechanical model of plunger-liquid column uplift inthe plunger-lift process was established, focusing on conventional plunger-lift systems and representative wellboreconfigurations in the Linxing region. The operating casing pressure of the plunger-lift process and the calculationmethod for the maximum daily fluid production rate based on the work regime with the highest fluid recovery ratewere determined. For the first time, the critical flow rate method was proposed as a constraint for the maximumliquid-carrying capacity of the plunger-lift, and liquid-carrying capacity charts for conventional plunger-lift withdifferent casing sizes were developed. The results showed that for 23/8 casing plunger-lift, with a well depth ofshallower than 808 m, the maximum drainage rate was 33 m3/d;for 27/8 casing plunger-lift, with a well depth ofshallower than 742 m, the maximum drainage rate was 50.15 m3/d;for 31/2 casing plunger-lift, with a well depthof shallower than 560 m, the maximum drainage rate was 75.14 m3/d. This research provides a foundation for thescientific selection of plunger-lift technology and serves as a decision-making reference for developing reasonableplunger-lift work regimes.
文摘Drone or unmanned aerial vehicle(UAV)technology has undergone significant changes.The technology allows UAV to carry out a wide range of tasks with an increasing level of sophistication,since drones can cover a large area with cameras.Meanwhile,the increasing number of computer vision applications utilizing deep learning provides a unique insight into such applications.The primary target in UAV-based detection applications is humans,yet aerial recordings are not included in the massive datasets used to train object detectors,which makes it necessary to gather the model data from such platforms.You only look once(YOLO)version 4,RetinaNet,faster region-based convolutional neural network(R-CNN),and cascade R-CNN are several well-known detectors that have been studied in the past using a variety of datasets to replicate rescue scenes.Here,we used the search and rescue(SAR)dataset to train the you only look once version 5(YOLOv5)algorithm to validate its speed,accuracy,and low false detection rate.In comparison to YOLOv4 and R-CNN,the highest mean average accuracy of 96.9%is obtained by YOLOv5.For comparison,experimental findings utilizing the SAR and the human rescue imaging database on land(HERIDAL)datasets are presented.The results show that the YOLOv5-based approach is the most successful human detection model for SAR missions.
基金Supported by Philosophy and Social Science Research Project of Hubei Education Department in 2022(22D092)Guiding Scientific Research Project of Shiyan Science and Technology Bureau in 2022(22Y34).
文摘[Objectives]This study aimed to investigate the incidence and risk factors associated with SSD in patients following cardiac surgery.[Methods]A total of 378 patients who underwent cardiac surgery in Taihe Hospital were recruited and screened.Diagnosis of delirium was made using evaluation methods and DSM-5 criteria.SSD was defined as the presence of one or more core features of delirium without meeting the full diagnostic criteria.Statistical analysis included independent samples t-test for group comparisons and binary logistic regression analysis to identify independent risk factors for SSD after cardiac surgery.[Results]Among the 378 subjects,112(29.63%)had SSD,28(7.41%)had delirium,and the remaining 238 patients(62.96%)did not present with delirium.Univariate analysis revealed that age,APACHE II score,duration of aortic clamping,length of ICU stay,duration of sedation use,and daily sleep time were significant risk factors for the occurrence of SSD(P<0.05).Logistic regression analysis identified age>70 years old,APACHE II score>20 points,length of ICU stay>5 d,and duration of sedation use>24 h as independent risk factors for SSD after cardiac surgery(P<0.05).A functional model was fitted based on the analysis results of the binary logistic regression model,yielding the equation logit P=1.472X_(1)+2.213X_(2)+3.028X_(3)+1.306X_(4).[Conclusions]Comprehensive clinical assessment is crucial for patients undergoing cardiac surgery,and appropriate preventive measures should be taken for patients with identified risk factors.Close monitoring of the patient s consciousness should be implemented postoperatively,and timely interventions should be conducted.Further research should focus on model validation and optimization.