The rapid development of information technology in the digital era has led the development and reform in the field of education.Both the transformation and high-quality development of open universities have put forwar...The rapid development of information technology in the digital era has led the development and reform in the field of education.Both the transformation and high-quality development of open universities have put forward higher requirements for open education governance.Focusing on the important field of open education governance,this study,from the perspective of university governance,deeply explores the practical dilemmas faced by open education governance,such as unclear development positioning,difficulties in transformation and development,inadequate learning support services,insufficient depth of teaching reform,and weak professional development of teachers.In the lifelong learning education ecology of universal education,open education governance should focus on“useful and easy learning”,focus on industry-education integration,take serving society as its purpose,and promote the transformation and development of open education.Under the concept of collaboration and co-governance,a multi-subject collaborative governance mechanism should be built,and governance thinking should be actively implemented in open education and teaching affairs to accelerate the modernization of open education governance.This aims to realize the sustainable development of open education governance and provide strong theoretical support and practical guidance for building a more fair,high-quality,and flexible open education governance system.展开更多
Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of ro...Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.展开更多
Chip surface character recognition is an important part of quality inspection in the field of microelectronics manufacturing.By recognizing the character information on the chip,automated production,quality control,an...Chip surface character recognition is an important part of quality inspection in the field of microelectronics manufacturing.By recognizing the character information on the chip,automated production,quality control,and data collection and analysis can be achieved.This article studies a chip surface character recognition method based on the OpenCV vision library.Firstly,the obtained chip images are preprocessed.Secondly,the template matching method is used to locate the chip position.In addition,the surface characters on the chip are individually segmented,and each character image is extracted separately.Finally,a Support Vector Machine(SVM)is used to classify and recognize characters.The results show that this method can accurately recognize the surface characters of chips and meet the requirements of chip quality inspection.展开更多
Objective:Placement of human placenta derived grafts during robotic-assisted radical prostatectomy(RARP)hastens the return of continence and potency.The long-term impact on the oncologic outcomes remains to be investi...Objective:Placement of human placenta derived grafts during robotic-assisted radical prostatectomy(RARP)hastens the return of continence and potency.The long-term impact on the oncologic outcomes remains to be investigated.Our objective was to determine the oncologic outcomes of patients with dehydrated human amnion chorion membrane(dHACM)at RARP compared to a matched cohort.Methods:In a referral centre,from August 2013 to October 2019,599 patients used dHACM in bilateral nerve-sparing RARP.We excluded patients with less than 12 months follow-up,simple prostatectomy,and unilateral nerve-sparing.Patients with dHACM(amnio group)were 529,and were propensity score matched 1:1 to 2465 patients without dHACM(non-amnio group)and a minimum follow-up of 36 months.At the time of RARP,dHACM was placed around the neurovascular bundle in the amnio group.Continuous and categorical variables in matched groups was tested by two-sample Kolmogorov-Smirnov test and Fisher's exact test respectively.Outcomes measured were biochemical recurrence(BCR),adjuvant and salvage therapy rates.Results:Propensity score matching resulted in two groups of 444 patients.Cumulative incidence functions for BCR did not show a difference between the groups(p=0.3).Patients in the non-amnio group required salvage therapy more frequently than the amnio group,particularly after partial nerve-sparing RARP(6.3%vs.2.3%,p=0.001).Limitations are the absence of prospective randomization.Conclusion:The data suggest that using dHACM does not have a negative impact on BCR in patients.Outcomes of cancer specific and overall survival will require follow-up study to increase our understanding of these grafts’impact on prostate cancer biology.展开更多
The process of sharing of data has become easier than ever with the advancement of cloud computing and software tools.However,big challenges remain such as efficient handling of big geospatial data,supporting and shar...The process of sharing of data has become easier than ever with the advancement of cloud computing and software tools.However,big challenges remain such as efficient handling of big geospatial data,supporting and sharing of crowd sourced/citizen science data,integration with semantic heterogeneity,and inclusion of agile processes for continuous improvement of geospatial technology.This paper discusses the new frontiers regarding these challenges and the related work performed by the Open Geospatial Consortium,the world leading organization focused on developing open geospatial standards that“geo-enable”the Web,wireless,and location-based services and mainstream IT.展开更多
This article is based on research conducted for the European CommissionEducation & Training 2020 working group on digital and online learning(ET2020 WG-DOL) specifically regarding policy challenges, such as thefol...This article is based on research conducted for the European CommissionEducation & Training 2020 working group on digital and online learning(ET2020 WG-DOL) specifically regarding policy challenges, such as thefollowing: 1) Targeted policy guidance on innovative and open learningenvironments under outcome;2) Proposal for a quality assurance modelfor open and innovative learning environments, its impact on specificassessment frameworks and its implication for EU recognition and transparencyinstruments. The article aims to define quality in open, flexible,and online learning, particularly in open education, open educationalresources (OER), and massive open online courses (MOOC). Hence,quality domains, characteristics, and criteria are outlined and discussed,as well as how they contribute to quality and personal learning so thatlearners can orchestrate and take responsibility for their own learningpathways. An additional goal is to identify the major stakeholders directlyinvolved in open online education and to describe their visions, communalities,and conflicts regarding quality in open, flexible, and online learning.The article also focuses on quality in periods of crisis, such as duringthe pandemic in 2020. Finally, the article discusses the rationale and needfor a model of quality in open, flexible, and online learning based on threemajor criteria for quality: excellence, impact, and implementation fromthe learner’s perspective.展开更多
There are a number of geotechnical systems used at open cut operations of Anglo American's Metallurgical Coal business unit in Australia. These systems are mainly mine site specific, based on geological informatio...There are a number of geotechnical systems used at open cut operations of Anglo American's Metallurgical Coal business unit in Australia. These systems are mainly mine site specific, based on geological information and used as hazard plans. They are qualitative and reliant upon the experienced judgement of site based engineers and the general workforce. They are not suitable for calculating the associated risks of geological structures and mining responses. A uniform risk rating system that can be used to provide an unbiased, standard and quantifiable assessment of the risk from highwall and lowwall failures is therefore developed using the experience gained with such systems in Anglo American's South African operations. This system is a semi-quantitative risk rating system and takes into account the relative differences in the importance of hazards as experienced at each mine site as a result of different combinations of geotechnical factors and mining conditions. It is based on critical geotechnical and other parameters that have been identified by site mining engineers, geologists and geotechnical engineers. The primary advantage of this risk rating system is that all open cut mines in the Anglo American's Metallurgical Coal operations use a near identical system, which enables the user to compare the risk after each blast and with other mines. The system can be adjusted to meet local mine specific requirements. The implementation of this system, a computer program that automatically calculates the risks and recommends predetermined controls, has been made as practical and as easy to use as possible. This program can be used by personnel from other mining disciplines not directly related to geotechnical engineering.展开更多
Based on the Barro classical growth model, this paper introduces capital account openness and exchange rate volatility to conduct an empirical analysis using the panel data of 182 countries(regions) during 1970-2013 t...Based on the Barro classical growth model, this paper introduces capital account openness and exchange rate volatility to conduct an empirical analysis using the panel data of 182 countries(regions) during 1970-2013 to examine the combined effects of capital account openness and exchange rate risks on economic growth. Our findings are as follows:(1) Without considering exchange rate volatility, capital account openness is subject to a threshold effect, i.e. capital account openness significantly promotes the economic growth of middle-and high-income countries but exerts the opposite effect on low-income countries; and(2) after exchange rate volatility is taken into account, the growth effect of capital account openness is reduced and the greater the exchange rate volatility is, the smaller the marginal effect of capital account openness will be; sample-specific results also proved the existence of the threshold effect. This paper offers the following implications:(1) The effect of capital account openness can be better examined based on risk factors;(2) moderately controlling exchange rate volatility is conducive to acquiring greater benefits from capital account openness; and(3) the threshold effect of capital account openness cannot be overlooked.展开更多
Background: Minimally invasive surgery is becoming increasingly popular in the field of pancreatic surgery. However, there are few studies of robotic distal pancreatectomy(RDP) for pancreatic ductal adenocarcinoma(PDA...Background: Minimally invasive surgery is becoming increasingly popular in the field of pancreatic surgery. However, there are few studies of robotic distal pancreatectomy(RDP) for pancreatic ductal adenocarcinoma(PDAC). This study aimed to investigate the efficacy and feasibility of RDP for PDAC. Methods: Patients who underwent RDP or laparoscopic distal pancreatectomy(LDP) for PDAC between January 2015 and September 2020 were reviewed. Propensity score matching analyses were performed. Results: Of the 335 patients included in the study, 24 underwent RDP and 311 underwent LDP. A total of 21 RDP patients were matched 1:1 with LDP patients. RDP was associated with longer operative time(209.7 vs. 163.2 min;P = 0.003), lower open conversion rate(0% vs. 4.8%;P < 0.001), higher cost(15 722 vs. 12 699 dollars;P = 0.003), and a higher rate of achievement of an R0 resection margin(90.5% vs. 61.9%;P = 0.042). However, postoperative pancreatic fistula grade B or C showed no significant intergroup difference(9.5% vs. 9.5%). The median disease-free survival(34.5 vs. 17.3 months;P = 0.588) and overall survival(37.7 vs. 21.9 months;P = 0.171) were comparable between the groups. Conclusions: RDP is associated with longer operative time, a higher cost of surgery, and a higher likelihood of achieving R0 margins than LDP.展开更多
The synthesis of T_8, T_ 10 and T_ 12 silsesquioxane cages from a range of starting materials: phenyl-cis-tetrol, 1,3-divinyltetraethoxydisiloxane and cyclopentyl T resins by using tetra n-butylammonium fluoride(TBA...The synthesis of T_8, T_ 10 and T_ 12 silsesquioxane cages from a range of starting materials: phenyl-cis-tetrol, 1,3-divinyltetraethoxydisiloxane and cyclopentyl T resins by using tetra n-butylammonium fluoride(TBAF) as the catalyst is described in this paper. The reaction yields obtained viathe current route are better compared to those viathe literature routes. Some of the cage compounds have been characterized by X-ray crystallography.展开更多
This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study f...This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study first focused on optimizing the strength of the sealant material and reducing curing time.This was achieved by regulating the slag doping and sodium silicate solution modulus.The findings demonstrated that increasing slag content and improving the material resulted in an early rise in strength while increasing the modulus of the sodium silicate solution extended the curing time.The slag doping level was fixed at 80 g,and the sodium silicate solution modulus was set at 1.5.To achieve a strength of 3.12 MPa,the water/gel ratio was set at 0.5.The initial setting time was determined to be 33 min,meeting the required field test duration.Secondly,the strength requirements for field implementation were assessed by simulating the action time and force destruction process of the sealing material during blasting using ANSYS/LS-DYNA software.The results indicated that the modified material meets these requirements.Finally,the Shengli Open Pit Coal Mine served as the site for the field test.It was observed that the hole-sealing material’s hydration reaction created a laminated and flocculated gel inside it.This enhanced the density of the modified material.Additionally,the pregelatinized starch,functioning as an organic binder,filled the gaps between the gels,enhancing the cohesion and bonding coefficient of the material.Upon analyzing the post-blasting shooting effect diagram using the Split-Desktop software,it was determined that the utilization of the modified blast hole plugging material resulted in a decrease in the rate of coal fragmentation from 33.2%to 21.1%.This reduction exhibited a minimal error of 1.63%when compared to the field measurement,thereby providing further confirmation of the exceptional plugging capabilities of the modified material.This study significantly contributes to establishing a solid theoretical basis for enhancing the blasting efficiency of open pit mines and,in turn,enhancing their economic advantages.展开更多
To ensure the success of the e-learning initiatives,OUM has developed its own e-learning management system,known as myLMS.Since its introduction,many modifications and improvements have been introduced to increase its...To ensure the success of the e-learning initiatives,OUM has developed its own e-learning management system,known as myLMS.Since its introduction,many modifications and improvements have been introduced to increase its effectiveness.It is now timely that OUM take stock of its students'attitudes towards e-learning.Thus,a survey was conducted on about 1,000 students at one of OUM's own learning centres,that is,the Kelantan Regional Centrel.The study indicated that generally the teacher cohort had a somewhat neutral attitude towards e-learning.The use of e-learning was more specifically aimed at achieving short term goals of obtaining good coursework and examination grades by capitalizing on the use of the Discussion Board and Courseware.A closer examination reveals that the females prefer the Discussion Board while the males prefer the Courseware.Learners in the Engineering and English programmes had more positive attitudes towards e-learning compared to learners in the Mathematics and Science programme. Learners with CGPA＞3.0 who are categorized as high achievers are more positive towards e-learning as compared to the low achievers(CGPA＜3.0).Age difference,learners‘income per month,learners’Internet and e-learning habits were also found to be predictors of attitude towards e-learning.展开更多
With the rapid development of network technology and digital construction,the era of“Internet+”has come,and“MOOCs”has brought a new revolution to education circles.The Open University,which takes modern distance e...With the rapid development of network technology and digital construction,the era of“Internet+”has come,and“MOOCs”has brought a new revolution to education circles.The Open University,which takes modern distance education as its basic education model,has put forward higher requirements for its teachers’competence.This paper analyzes the difficulties of teachers’competence under the impact of“Internet+”in order to improve the development of teachers’competence in local Open University.展开更多
Linux-based Platform for Open Architecture Controller ( POAC ), a new open architecture controller and its modular developing method are discussed. POAC divides the application software of controller into the developi...Linux-based Platform for Open Architecture Controller ( POAC ), a new open architecture controller and its modular developing method are discussed. POAC divides the application software of controller into the developing system and the application system. In the developing system, PAOC abstracts a series of function modules with unified data interface and function interface. In the application system, POAC defines the model of the architecture module, realizing the interoperability and interchangeability between the architecture modules. The modular developing method entities the users to make up an application system with some architecture modules, which consist of a set of function modules. The modular developing method decreases the developing time from the standard of controller architecture to the product.展开更多
基金2022 Education and Teaching Research and Reform Project of Guangdong Open University System,“Practical Dilemmas and Practical Paths of Educational Governance in Open Education in the Post-Pandemic Era”(Project No.:2022TXJG35)。
文摘The rapid development of information technology in the digital era has led the development and reform in the field of education.Both the transformation and high-quality development of open universities have put forward higher requirements for open education governance.Focusing on the important field of open education governance,this study,from the perspective of university governance,deeply explores the practical dilemmas faced by open education governance,such as unclear development positioning,difficulties in transformation and development,inadequate learning support services,insufficient depth of teaching reform,and weak professional development of teachers.In the lifelong learning education ecology of universal education,open education governance should focus on“useful and easy learning”,focus on industry-education integration,take serving society as its purpose,and promote the transformation and development of open education.Under the concept of collaboration and co-governance,a multi-subject collaborative governance mechanism should be built,and governance thinking should be actively implemented in open education and teaching affairs to accelerate the modernization of open education governance.This aims to realize the sustainable development of open education governance and provide strong theoretical support and practical guidance for building a more fair,high-quality,and flexible open education governance system.
基金supported by the National Key Research and Development Program of China(No.2022YFC2903902)the National Natural Science Foundation of China(Nos.52204080and 52174070)the Fundamental Research Funds for the Central Universities of China(No.2023GFYD17)。
文摘Accurately predicting the powder factor during blasting is essential for sustainable production planning in low-grade mines.This research presents a method for predicting powder factor based on the heterogeneity of rock mass rating(RMR).Considering a low-grade metal mine as an example,this study exploited geostatistical methods to obtain independent RMR for each block unit.A three-dimensional spatial distribution model for the powder factor was developed on the basis of the relationships between the RMR and the powder factor.Subsequently,models for blasting cost and mining value were built and employed to optimize the open-pit limit.The multi-variable model based on the RMR performed well in predicting the powder factor,achieving a correlation coefficient of 0.88(root mean square error of 4.3)and considerably outperforming the uniaxial compressive strength model.After model optimization,the mean size and standard deviation of the fragments in the blast pile decreased by 8.5%and 35.1%,respectively,whereas the boulder yield and its standard deviation decreased by 33.3%and 58.8%,respectively.Additionally,optimizing the open-pit limit using this method reduced the amount of rock,increased the amount of ore,and lowered blasting costs,thereby enhancing the economic efficiency of the mine.This study provides valuable insights for blasting design and mining decisions,demonstrating the advantages and potential applications of powder factor prediction based on the heterogeneity of rock mass quality.
基金Henan Province Science and Technology Research Project“Key Technologies for Intelligent Recognition of Chip Surface Defects Based on Machine Vision”(Project No.242102210161).
文摘Chip surface character recognition is an important part of quality inspection in the field of microelectronics manufacturing.By recognizing the character information on the chip,automated production,quality control,and data collection and analysis can be achieved.This article studies a chip surface character recognition method based on the OpenCV vision library.Firstly,the obtained chip images are preprocessed.Secondly,the template matching method is used to locate the chip position.In addition,the surface characters on the chip are individually segmented,and each character image is extracted separately.Finally,a Support Vector Machine(SVM)is used to classify and recognize characters.The results show that this method can accurately recognize the surface characters of chips and meet the requirements of chip quality inspection.
文摘Objective:Placement of human placenta derived grafts during robotic-assisted radical prostatectomy(RARP)hastens the return of continence and potency.The long-term impact on the oncologic outcomes remains to be investigated.Our objective was to determine the oncologic outcomes of patients with dehydrated human amnion chorion membrane(dHACM)at RARP compared to a matched cohort.Methods:In a referral centre,from August 2013 to October 2019,599 patients used dHACM in bilateral nerve-sparing RARP.We excluded patients with less than 12 months follow-up,simple prostatectomy,and unilateral nerve-sparing.Patients with dHACM(amnio group)were 529,and were propensity score matched 1:1 to 2465 patients without dHACM(non-amnio group)and a minimum follow-up of 36 months.At the time of RARP,dHACM was placed around the neurovascular bundle in the amnio group.Continuous and categorical variables in matched groups was tested by two-sample Kolmogorov-Smirnov test and Fisher's exact test respectively.Outcomes measured were biochemical recurrence(BCR),adjuvant and salvage therapy rates.Results:Propensity score matching resulted in two groups of 444 patients.Cumulative incidence functions for BCR did not show a difference between the groups(p=0.3).Patients in the non-amnio group required salvage therapy more frequently than the amnio group,particularly after partial nerve-sparing RARP(6.3%vs.2.3%,p=0.001).Limitations are the absence of prospective randomization.Conclusion:The data suggest that using dHACM does not have a negative impact on BCR in patients.Outcomes of cancer specific and overall survival will require follow-up study to increase our understanding of these grafts’impact on prostate cancer biology.
文摘The process of sharing of data has become easier than ever with the advancement of cloud computing and software tools.However,big challenges remain such as efficient handling of big geospatial data,supporting and sharing of crowd sourced/citizen science data,integration with semantic heterogeneity,and inclusion of agile processes for continuous improvement of geospatial technology.This paper discusses the new frontiers regarding these challenges and the related work performed by the Open Geospatial Consortium,the world leading organization focused on developing open geospatial standards that“geo-enable”the Web,wireless,and location-based services and mainstream IT.
文摘This article is based on research conducted for the European CommissionEducation & Training 2020 working group on digital and online learning(ET2020 WG-DOL) specifically regarding policy challenges, such as thefollowing: 1) Targeted policy guidance on innovative and open learningenvironments under outcome;2) Proposal for a quality assurance modelfor open and innovative learning environments, its impact on specificassessment frameworks and its implication for EU recognition and transparencyinstruments. The article aims to define quality in open, flexible,and online learning, particularly in open education, open educationalresources (OER), and massive open online courses (MOOC). Hence,quality domains, characteristics, and criteria are outlined and discussed,as well as how they contribute to quality and personal learning so thatlearners can orchestrate and take responsibility for their own learningpathways. An additional goal is to identify the major stakeholders directlyinvolved in open online education and to describe their visions, communalities,and conflicts regarding quality in open, flexible, and online learning.The article also focuses on quality in periods of crisis, such as duringthe pandemic in 2020. Finally, the article discusses the rationale and needfor a model of quality in open, flexible, and online learning based on threemajor criteria for quality: excellence, impact, and implementation fromthe learner’s perspective.
文摘There are a number of geotechnical systems used at open cut operations of Anglo American's Metallurgical Coal business unit in Australia. These systems are mainly mine site specific, based on geological information and used as hazard plans. They are qualitative and reliant upon the experienced judgement of site based engineers and the general workforce. They are not suitable for calculating the associated risks of geological structures and mining responses. A uniform risk rating system that can be used to provide an unbiased, standard and quantifiable assessment of the risk from highwall and lowwall failures is therefore developed using the experience gained with such systems in Anglo American's South African operations. This system is a semi-quantitative risk rating system and takes into account the relative differences in the importance of hazards as experienced at each mine site as a result of different combinations of geotechnical factors and mining conditions. It is based on critical geotechnical and other parameters that have been identified by site mining engineers, geologists and geotechnical engineers. The primary advantage of this risk rating system is that all open cut mines in the Anglo American's Metallurgical Coal operations use a near identical system, which enables the user to compare the risk after each blast and with other mines. The system can be adjusted to meet local mine specific requirements. The implementation of this system, a computer program that automatically calculates the risks and recommends predetermined controls, has been made as practical and as easy to use as possible. This program can be used by personnel from other mining disciplines not directly related to geotechnical engineering.
基金Key Project of the Social Sciences Foundation of China(Grant No.15ZDA014)Foundation for High-level Talents in Higher Education of Guangdong(Pearl River Scholar 1414003)Doctoral Start-Up Project of the National Natural Science Foundation of Guangdong(2014A030310079)
文摘Based on the Barro classical growth model, this paper introduces capital account openness and exchange rate volatility to conduct an empirical analysis using the panel data of 182 countries(regions) during 1970-2013 to examine the combined effects of capital account openness and exchange rate risks on economic growth. Our findings are as follows:(1) Without considering exchange rate volatility, capital account openness is subject to a threshold effect, i.e. capital account openness significantly promotes the economic growth of middle-and high-income countries but exerts the opposite effect on low-income countries; and(2) after exchange rate volatility is taken into account, the growth effect of capital account openness is reduced and the greater the exchange rate volatility is, the smaller the marginal effect of capital account openness will be; sample-specific results also proved the existence of the threshold effect. This paper offers the following implications:(1) The effect of capital account openness can be better examined based on risk factors;(2) moderately controlling exchange rate volatility is conducive to acquiring greater benefits from capital account openness; and(3) the threshold effect of capital account openness cannot be overlooked.
文摘Background: Minimally invasive surgery is becoming increasingly popular in the field of pancreatic surgery. However, there are few studies of robotic distal pancreatectomy(RDP) for pancreatic ductal adenocarcinoma(PDAC). This study aimed to investigate the efficacy and feasibility of RDP for PDAC. Methods: Patients who underwent RDP or laparoscopic distal pancreatectomy(LDP) for PDAC between January 2015 and September 2020 were reviewed. Propensity score matching analyses were performed. Results: Of the 335 patients included in the study, 24 underwent RDP and 311 underwent LDP. A total of 21 RDP patients were matched 1:1 with LDP patients. RDP was associated with longer operative time(209.7 vs. 163.2 min;P = 0.003), lower open conversion rate(0% vs. 4.8%;P < 0.001), higher cost(15 722 vs. 12 699 dollars;P = 0.003), and a higher rate of achievement of an R0 resection margin(90.5% vs. 61.9%;P = 0.042). However, postoperative pancreatic fistula grade B or C showed no significant intergroup difference(9.5% vs. 9.5%). The median disease-free survival(34.5 vs. 17.3 months;P = 0.588) and overall survival(37.7 vs. 21.9 months;P = 0.171) were comparable between the groups. Conclusions: RDP is associated with longer operative time, a higher cost of surgery, and a higher likelihood of achieving R0 margins than LDP.
文摘The synthesis of T_8, T_ 10 and T_ 12 silsesquioxane cages from a range of starting materials: phenyl-cis-tetrol, 1,3-divinyltetraethoxydisiloxane and cyclopentyl T resins by using tetra n-butylammonium fluoride(TBAF) as the catalyst is described in this paper. The reaction yields obtained viathe current route are better compared to those viathe literature routes. Some of the cage compounds have been characterized by X-ray crystallography.
基金financially supported by the National Natural Science Foundation of China (No. 52174131)
文摘This research proposes the utilization of a geopolymer-based blasting sealing material to improve the profitability of coal sales and reduce the rate of coal fragmentation during blasting in open pit mines.The study first focused on optimizing the strength of the sealant material and reducing curing time.This was achieved by regulating the slag doping and sodium silicate solution modulus.The findings demonstrated that increasing slag content and improving the material resulted in an early rise in strength while increasing the modulus of the sodium silicate solution extended the curing time.The slag doping level was fixed at 80 g,and the sodium silicate solution modulus was set at 1.5.To achieve a strength of 3.12 MPa,the water/gel ratio was set at 0.5.The initial setting time was determined to be 33 min,meeting the required field test duration.Secondly,the strength requirements for field implementation were assessed by simulating the action time and force destruction process of the sealing material during blasting using ANSYS/LS-DYNA software.The results indicated that the modified material meets these requirements.Finally,the Shengli Open Pit Coal Mine served as the site for the field test.It was observed that the hole-sealing material’s hydration reaction created a laminated and flocculated gel inside it.This enhanced the density of the modified material.Additionally,the pregelatinized starch,functioning as an organic binder,filled the gaps between the gels,enhancing the cohesion and bonding coefficient of the material.Upon analyzing the post-blasting shooting effect diagram using the Split-Desktop software,it was determined that the utilization of the modified blast hole plugging material resulted in a decrease in the rate of coal fragmentation from 33.2%to 21.1%.This reduction exhibited a minimal error of 1.63%when compared to the field measurement,thereby providing further confirmation of the exceptional plugging capabilities of the modified material.This study significantly contributes to establishing a solid theoretical basis for enhancing the blasting efficiency of open pit mines and,in turn,enhancing their economic advantages.
文摘To ensure the success of the e-learning initiatives,OUM has developed its own e-learning management system,known as myLMS.Since its introduction,many modifications and improvements have been introduced to increase its effectiveness.It is now timely that OUM take stock of its students'attitudes towards e-learning.Thus,a survey was conducted on about 1,000 students at one of OUM's own learning centres,that is,the Kelantan Regional Centrel.The study indicated that generally the teacher cohort had a somewhat neutral attitude towards e-learning.The use of e-learning was more specifically aimed at achieving short term goals of obtaining good coursework and examination grades by capitalizing on the use of the Discussion Board and Courseware.A closer examination reveals that the females prefer the Discussion Board while the males prefer the Courseware.Learners in the Engineering and English programmes had more positive attitudes towards e-learning compared to learners in the Mathematics and Science programme. Learners with CGPA＞3.0 who are categorized as high achievers are more positive towards e-learning as compared to the low achievers(CGPA＜3.0).Age difference,learners‘income per month,learners’Internet and e-learning habits were also found to be predictors of attitude towards e-learning.
文摘With the rapid development of network technology and digital construction,the era of“Internet+”has come,and“MOOCs”has brought a new revolution to education circles.The Open University,which takes modern distance education as its basic education model,has put forward higher requirements for its teachers’competence.This paper analyzes the difficulties of teachers’competence under the impact of“Internet+”in order to improve the development of teachers’competence in local Open University.
基金Shanghai Science and Technology Development Foundation (995107017)
文摘Linux-based Platform for Open Architecture Controller ( POAC ), a new open architecture controller and its modular developing method are discussed. POAC divides the application software of controller into the developing system and the application system. In the developing system, PAOC abstracts a series of function modules with unified data interface and function interface. In the application system, POAC defines the model of the architecture module, realizing the interoperability and interchangeability between the architecture modules. The modular developing method entities the users to make up an application system with some architecture modules, which consist of a set of function modules. The modular developing method decreases the developing time from the standard of controller architecture to the product.
