Taking the construction of PPP project of Guangzhou North Railway Station Comprehensive Transportation Hub as an example,the related measures of construction project quality management and cost control are discussed i...Taking the construction of PPP project of Guangzhou North Railway Station Comprehensive Transportation Hub as an example,the related measures of construction project quality management and cost control are discussed in detail,and it is hoped to have reference.展开更多
For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological...For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.展开更多
Objective To explore the value of deep learning(DL)models semi-automatic training system for automatic optimization of clinical image quality control of transthoracic echocardiography(TTE).Methods Totally 1250 TTE vid...Objective To explore the value of deep learning(DL)models semi-automatic training system for automatic optimization of clinical image quality control of transthoracic echocardiography(TTE).Methods Totally 1250 TTE videos from 402 patients were retrospectively collected,including 490 apical four chamber(A4C),310 parasternal long axis view of left ventricle(PLAX)and 450 parasternal short axis view of great vessel(PSAX GV).The videos were divided into development set(245 A4C,155 PLAX,225 PSAX GV),semi-automated training set(98 A4C,62 PLAX,90 PSAX GV)and test set(147 A4C,93 PLAX,135 PSAX GV)at the ratio of 5∶2∶3.Based on development set and semi-automatic training set,DL model of quality control was semi-automatically iteratively optimized,and a semi-automatic training system was constructed,then the efficacy of DL models for recognizing TTE views and assessing imaging quality of TTE were verified in test set.Results After optimization,the overall accuracy,precision,recall,and F1 score of DL models for recognizing TTE views in test set improved from 97.33%,97.26%,97.26%and 97.26%to 99.73%,99.65%,99.77%and 99.71%,respectively,while the overall accuracy for assessing A4C,PLAX and PSAX GV TTE as standard views in test set improved from 89.12%,83.87%and 90.37%to 93.20%,90.32%and 93.33%,respectively.Conclusion The developed DL models semi-automatic training system could improve the efficiency of clinical imaging quality control of TTE and increase iteration speed.展开更多
In the last decade,3D printing,especially fused deposition modeling(FDM),has revolutionized manufacturing with intricate designs.Traditional 3-axis FDM printers face challenges with complex geometries,but 5-axis versi...In the last decade,3D printing,especially fused deposition modeling(FDM),has revolutionized manufacturing with intricate designs.Traditional 3-axis FDM printers face challenges with complex geometries,but 5-axis versions offer more design freedom.However,it requires specialized strategies.This research presents a model for 5-axis FDM printers using Bézier curves with an algorithm to enhance print quality.The result shows significant accuracy improvements,especially for curve-based tasks.In addition,this study deepens the understanding of 5-axis FDM technology,setting a solid basis for further research and potentially refining manufacturing methods.展开更多
The gut microbiota is a complex ecosystem composed of many bacteria and their metabolites.It plays an irreplaceable role in human digestion,nutrient absorption,energy supply,fat metabolism,immune regulation,and many o...The gut microbiota is a complex ecosystem composed of many bacteria and their metabolites.It plays an irreplaceable role in human digestion,nutrient absorption,energy supply,fat metabolism,immune regulation,and many other aspects.Exploring the structure and function of the gut microbiota,as well as their key genes and metabolites,will enable the early diagnosis and auxiliary diagnosis of diseases,new treatment methods,better effects of drug treatments,and better guidance in the use of antibiotics.The identification of gut microbiota plays an important role in clinical diagnosis and treatment,as well as in drug research and development.Therefore,it is necessary to conduct a comprehensive review of this rapidly evolving topic.Traditional identification methods cannot comprehensively capture the diversity of gut microbiota.Currently,with the rapid development of molecular biology,the classification and identification methods for gut microbiota have evolved from the initial phenotypic and chemical identification to identification at the molecular level.This review integrates the main methods of gut microbiota identification and evaluates their application.We pay special attention to the research progress on molecular biological methods and focus on the application of high-throughput sequencing technology in the identification of gut microbiota.This revolutionary method for intestinal flora identification heralds a new chapter in our understanding of the microbial world.展开更多
A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, Ch...A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, China. Results showed that at 20℃ mass loss of leaf litter driven by microbial decomposers was higher in broadleaf forest than that in coniferous forest, whereas the difference in mass loss of leaf litter was not significant at 30℃. The temperature increase did not affect the mass loss of leaf litter for coniferous forest treatment, but significantly reduced the decomposition rate for broadleaf forest treatment. The functional decomposers of microorganism in broadleaf forest produced a higher lignin decomposition rate at 20℃, compared to that in coniferous forest, but the difference in lignin decomposition was not found between two forest types at 30℃. Improved temperature increased the lignin decomposition for both broadleaf and coniferous forest. Additionally, the functional group of microorganism from broadleaf forest showed marginally higher carbohydrate loss than that from coniferous forest at both temperatures. Temperature increase reduced the carbohydrate decomposition for broadleaf forest, while only a little reduce was found for coniferous forest. Remarkable differences occurred in responses between most enzymes (Phenoloxidase, peroxidase, !5-glucosidase and endocellulase) and decomposition rate of leaf litter to forest type and temperature, although there exist strong relationships between measured enzyme activities and decomposition rate in most cases. The reason is that more than one enzyme contribute to the mass loss of leaf litter and organic chemical components. In conclusion, at a community scale the coniferous and broadleaf forests differed in their temperature-decomposition relationships.展开更多
In order to study the wear behavior of different kinds of contact wires,the dry sliding wear behaviors of Cu-Sn,Cu-Ag and Cu-Mg alloys prepared by up-drawn continuous casting and followed continuous extrusion were stu...In order to study the wear behavior of different kinds of contact wires,the dry sliding wear behaviors of Cu-Sn,Cu-Ag and Cu-Mg alloys prepared by up-drawn continuous casting and followed continuous extrusion were studied.The research was tested on a block-on-ring wear tester.The results indicate that the friction coefficient is remarkably influenced by the formation of a continuous tribofilm,which consists of oxidation film.The abrasion,adhesion,oxidation and plastic deformation are observed.Oxidation and abrasion wear mechanisms dominate at the lower sliding velocity and load.The combination of oxidation and adhesion play leading roles with the increasing load and velocity.Plastic deformation is detected under higher applied load and sliding velocities.展开更多
In order to enable quality-aware web services selection in the process of service composition,this paper first describes the non-functional requirements of service consumers and the quality of elementary service or co...In order to enable quality-aware web services selection in the process of service composition,this paper first describes the non-functional requirements of service consumers and the quality of elementary service or composite service as a quality vector,and then models the QoS(quality of service)-aware composition as a multiple criteria optimization problem in extending directed graph.A novel simulated annealing algorithm for QoS-aware web services composition is presented.A normalizing for composite service QoS values is made,and a secondary iterative optimization is used in the algorithm.Experimental results show that the simulated annealing algorithm can satisfy the multiple criteria and global QoS requirements of service consumers.The algorithm produces near optimum solution with much less computation cost.展开更多
ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined w...ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined with the increase of seedling density. The reasonable density of seedlings is key to cultivate high-quality seedlings and achieve the best seedling efficiency. The optimum density was 30 plants/m2 for the first class seedlings of biennial seedlings, and the optimum density of l and ll seedlings for production afforestation was 40 plants/m2.展开更多
According to the actual conditions in Sanshandao Gold Mine, the cancelling ore pillars mining method was researched. Firstly, a series of tests for the physical and mechanical characteristics of rock mass were carried...According to the actual conditions in Sanshandao Gold Mine, the cancelling ore pillars mining method was researched. Firstly, a series of tests for the physical and mechanical characteristics of rock mass were carried out and a quality classification system of rock mass applied in coastal metal deposit was established. Secondly, the reasonable demarcation depth of cancelling ore pillars was simulated using the finite element method, and the simulation results show that the ore pillars can be cancelled below the level of-555 m. Thirdly, a novel layer-backfill mining method of room-pillar alternation was designed to reduce the disturbance and settlement of terrain in mining area. Engineering practice shows that the new mining method enhanced the mining output and relieved rock disturbance. Furthermore, the settlement of the roof strata was small and no disaster occurred. The new mining technology effectively controlled the deformation of the terrain, indicating that the mining of the large-scale gold coastal deposit in Sanshandao Gold Mine was achieved safely, efficiently, and with a low loss rate.展开更多
Based on the analysis of monitoring data on six pollution indexes of SO2, NO2, CO, O3, PM10 and PM2.5 from 53 monitoring points in 7 cities, including Beijing, Tianjin, Shijiazhuang, etc., from April 8 of 2014 to July...Based on the analysis of monitoring data on six pollution indexes of SO2, NO2, CO, O3, PM10 and PM2.5 from 53 monitoring points in 7 cities, including Beijing, Tianjin, Shijiazhuang, etc., from April 8 of 2014 to July 23 of 2014, this article adopted Pearson correlation coefficient method to determine the relevance among each pollutant of these cities with the help of SPSS. The results showed that such three leading indexes as SO2, PM10 and PM2.5 had strong correlation in Beijing, Tianjin and main cities of Hebei. Finally, some suggestions and preventive measures for the cooperative governance of air pollution in Beijing-Tianjin-Hebei Region were put forward, hoping this can help them.展开更多
The functional fractions (acid, basic, amphoteric and neutral fractions) are isolated from the Liaohe Du-84 heavy crude oil and Shengli Gudao Kenxi heavy crude oil by ion-exchange chromatography, but the conventional...The functional fractions (acid, basic, amphoteric and neutral fractions) are isolated from the Liaohe Du-84 heavy crude oil and Shengli Gudao Kenxi heavy crude oil by ion-exchange chromatography, but the conventional fractions (saturates, aromatics, resins and asphaltenes) are also isolated from the heavy crude oil. These components have been characterized by spectroscopic methods (FT-IR), namely acid number, basic nitrogen number, ultimate analysis and molecular weight measurements using vapor pressure osmometry (VPO). The ion-exchange chromatography method based on separation by a functional group induces a little change on the nature of the crudes and reasonable mass balances can be easily obtained.展开更多
The utilization and changes of forest resources were studied in the Lishuihe Forest Bureau. Based on remote sensing images in 1985 and 1999, changes of major forest resources were analyzed by statistical and overlap m...The utilization and changes of forest resources were studied in the Lishuihe Forest Bureau. Based on remote sensing images in 1985 and 1999, changes of major forest resources were analyzed by statistical and overlap method and classified quantitatively. The results showed that in recent 15 years, logging spots and man-made young forest changed violently, which was due to human activities. Different forest management manners and harvesting intensity played an important role in forest resources change. Dongsheng and Xilinhe tree farms were typical cases of different forest status and management for the Bu-reau, where forest succession was intervened by either human or natural disturbance. Dongsheng Tree Farm underwent a light harvest intensity and maintained a unit stock volume of 536.27 m3hm-2, as much as that of broadleaf/Korean pine forest of Changbai Mountain Natural Reserve; Xilinhe Tree Farm underwent an intense harvest and was composed of secondary forests, where mature forests just had a small percentage and the unit stock volume was low. The study was useful to guide future forest management. What抯 more, problems found in the research were also analyzed and reasonable advice was given to the local forest management.展开更多
[Objective]The aim of this study was to set up a high performance liquid chromatography for rapid determination of isoflavones from soybean and analyze the correlation between isofalvone content and protein or fat con...[Objective]The aim of this study was to set up a high performance liquid chromatography for rapid determination of isoflavones from soybean and analyze the correlation between isofalvone content and protein or fat content. [Method]The isoflavones were firstly extracted by 80% methanol and then hydrolyzed at 100 ℃. The chromatographic separation adopted a reversed-phase C18 analytical column with binary high-pressure gradient elution,while its analysis time was 25 min and column temperature was 40 ℃. The diode array detector was used for monitoring with wavelength of 260 nm. The correlation between isofalvone content and protein or fat content was analyzed by data processing system Origin 6.0. [Result]The high performance liquid chromatograph for determination of isoflavones from soybean was verified to be accurate and reliable by methodology. The isoflavones of 85 soybean lines cultivated in Jilin Province were determined,and the results primarily showed the characters and ranges of isoflavones from soybean lines cultivated in Jilin Province,while the isoflavone content of soybeans ranged from 2.29 to 4.89 mg/g,and the average content was 3.36 mg/g. The isoflavone content of 5 soybean lines exceeded 4 mg/g,while there was a remarkably negative correlation between isoflavone content and protein content,and there was no significant positive correlation between isoflavone content and fat content. [Conclusion]The isoflavone content of soybean lines cultivated in Jilin Province is higher,so it is feasible for breeding the soybean lines with high isoflavone content and fat contetnt.展开更多
[Objective] The paper is to construct the logistics tracking management system of tropical agricultural products based on supply chain.[Method] With tropical agricultural products in Hainan as study object,based on lo...[Objective] The paper is to construct the logistics tracking management system of tropical agricultural products based on supply chain.[Method] With tropical agricultural products in Hainan as study object,based on logistics supply chain files and electronic tag coding of agricultural products,cold chain temperature and humidity monitoring,vehicle transportation positioning,data exchange of XML Web services and role-based permission dynamic allocation,the multi-level multi-permission and multi-role logistics tracking management system of tropical agricultural products has been established.[Result] The system constructs information exchange platform for various links of logistics supply chain of tropical agricultural products,which realizes the entire quality monitoring and information tracing of agricultural products,thus enhancing the competitiveness of supply chain in company.[Conclusion] The system has good application and extension prospect.展开更多
文摘Taking the construction of PPP project of Guangzhou North Railway Station Comprehensive Transportation Hub as an example,the related measures of construction project quality management and cost control are discussed in detail,and it is hoped to have reference.
基金supported by the Guangxi Natural Science Foundation(2020GXNSFAA297266)Doctoral Research Foundation of Guilin University of Technology(GUTQDJJ2007059)Guangxi Hidden Metallic Mineral Exploration Key Laboratory。
文摘For regional ecological management,it is important to evaluate the quality of ecosystems and analyze the underlying causes of ecological changes.Using the Google Earth Engine(GEE)platform,the remote sensing ecological index(RSEI)was calculated for the Lijiang River Basin in Guangxi Zhuang Autonomous Region for 1991,2001,2011,and 2021.Spatial autocorrelation analysis was employed to investigate spatiotemporal variations in the ecological environmental quality of the Lijiang River Basin.Furthermore,geographic detectors were used to quantitatively analyze influencing factors and their interaction effects on ecological environmental quality.The results verified that:1)From 1991 to 2021,the ecological environmental quality of the Lijiang River Basin demonstrated significant improvement.The area with good and excellent ecological environmental quality in proportion increased by 19.69%(3406.57 km^(2)),while the area with fair and poor ecological environmental quality in proportion decreased by 10.76%(1860.36 km^(2)).2)Spatially,the ecological environmental quality of the Lijiang River Basin exhibited a pattern of low quality in the central region and high quality in the periphery.Specifically,poor ecological environmental quality characterized the Guilin urban area,Pingle County,and Lingchuan County.3)From 1991 to 2021,a significant positive spatial correlation was observed in ecological environmental quality of the Lijiang River Basin.Areas with high-high agglomeration were predominantly forests and grasslands,indicating good ecological environmental quality,whereas areas with low-low agglomeration were dominated by cultivated land and construction land,indicating poor ecological environmental quality.4)Annual average precipitation and temperature exerted the most significant influence on the ecological environmental quality of the basin,and their interactions with other factors had the great influence.This study aimed to enhance understanding of the evolution of the ecological environment in the Lijiang River Basin of Guangxi Zhuang Autonomous Region and provide scientific guidance for decision-making and management related to ecology in the region.
文摘Objective To explore the value of deep learning(DL)models semi-automatic training system for automatic optimization of clinical image quality control of transthoracic echocardiography(TTE).Methods Totally 1250 TTE videos from 402 patients were retrospectively collected,including 490 apical four chamber(A4C),310 parasternal long axis view of left ventricle(PLAX)and 450 parasternal short axis view of great vessel(PSAX GV).The videos were divided into development set(245 A4C,155 PLAX,225 PSAX GV),semi-automated training set(98 A4C,62 PLAX,90 PSAX GV)and test set(147 A4C,93 PLAX,135 PSAX GV)at the ratio of 5∶2∶3.Based on development set and semi-automatic training set,DL model of quality control was semi-automatically iteratively optimized,and a semi-automatic training system was constructed,then the efficacy of DL models for recognizing TTE views and assessing imaging quality of TTE were verified in test set.Results After optimization,the overall accuracy,precision,recall,and F1 score of DL models for recognizing TTE views in test set improved from 97.33%,97.26%,97.26%and 97.26%to 99.73%,99.65%,99.77%and 99.71%,respectively,while the overall accuracy for assessing A4C,PLAX and PSAX GV TTE as standard views in test set improved from 89.12%,83.87%and 90.37%to 93.20%,90.32%and 93.33%,respectively.Conclusion The developed DL models semi-automatic training system could improve the efficiency of clinical imaging quality control of TTE and increase iteration speed.
基金supported by the Na-tional Natural Science Foundation of China(Nos.51575266,52075258)。
文摘In the last decade,3D printing,especially fused deposition modeling(FDM),has revolutionized manufacturing with intricate designs.Traditional 3-axis FDM printers face challenges with complex geometries,but 5-axis versions offer more design freedom.However,it requires specialized strategies.This research presents a model for 5-axis FDM printers using Bézier curves with an algorithm to enhance print quality.The result shows significant accuracy improvements,especially for curve-based tasks.In addition,this study deepens the understanding of 5-axis FDM technology,setting a solid basis for further research and potentially refining manufacturing methods.
文摘The gut microbiota is a complex ecosystem composed of many bacteria and their metabolites.It plays an irreplaceable role in human digestion,nutrient absorption,energy supply,fat metabolism,immune regulation,and many other aspects.Exploring the structure and function of the gut microbiota,as well as their key genes and metabolites,will enable the early diagnosis and auxiliary diagnosis of diseases,new treatment methods,better effects of drug treatments,and better guidance in the use of antibiotics.The identification of gut microbiota plays an important role in clinical diagnosis and treatment,as well as in drug research and development.Therefore,it is necessary to conduct a comprehensive review of this rapidly evolving topic.Traditional identification methods cannot comprehensively capture the diversity of gut microbiota.Currently,with the rapid development of molecular biology,the classification and identification methods for gut microbiota have evolved from the initial phenotypic and chemical identification to identification at the molecular level.This review integrates the main methods of gut microbiota identification and evaluates their application.We pay special attention to the research progress on molecular biological methods and focus on the application of high-throughput sequencing technology in the identification of gut microbiota.This revolutionary method for intestinal flora identification heralds a new chapter in our understanding of the microbial world.
基金This study was supported by National Natural Sci-ence Foundation of China (30470299)Key Project of National Sci-ence Foundation of China (30430570).
文摘A study was conducted to identify the differences in the decompositions of leaf litter, lignin and carbohydrate between coniferous forest and broadleaf forest at 20℃ and 30℃ in Huangshan Mountain, Anhui Province, China. Results showed that at 20℃ mass loss of leaf litter driven by microbial decomposers was higher in broadleaf forest than that in coniferous forest, whereas the difference in mass loss of leaf litter was not significant at 30℃. The temperature increase did not affect the mass loss of leaf litter for coniferous forest treatment, but significantly reduced the decomposition rate for broadleaf forest treatment. The functional decomposers of microorganism in broadleaf forest produced a higher lignin decomposition rate at 20℃, compared to that in coniferous forest, but the difference in lignin decomposition was not found between two forest types at 30℃. Improved temperature increased the lignin decomposition for both broadleaf and coniferous forest. Additionally, the functional group of microorganism from broadleaf forest showed marginally higher carbohydrate loss than that from coniferous forest at both temperatures. Temperature increase reduced the carbohydrate decomposition for broadleaf forest, while only a little reduce was found for coniferous forest. Remarkable differences occurred in responses between most enzymes (Phenoloxidase, peroxidase, !5-glucosidase and endocellulase) and decomposition rate of leaf litter to forest type and temperature, although there exist strong relationships between measured enzyme activities and decomposition rate in most cases. The reason is that more than one enzyme contribute to the mass loss of leaf litter and organic chemical components. In conclusion, at a community scale the coniferous and broadleaf forests differed in their temperature-decomposition relationships.
基金Projects(51134013,51074031,51274054)supported by the National Natural Science Foundation of China
文摘In order to study the wear behavior of different kinds of contact wires,the dry sliding wear behaviors of Cu-Sn,Cu-Ag and Cu-Mg alloys prepared by up-drawn continuous casting and followed continuous extrusion were studied.The research was tested on a block-on-ring wear tester.The results indicate that the friction coefficient is remarkably influenced by the formation of a continuous tribofilm,which consists of oxidation film.The abrasion,adhesion,oxidation and plastic deformation are observed.Oxidation and abrasion wear mechanisms dominate at the lower sliding velocity and load.The combination of oxidation and adhesion play leading roles with the increasing load and velocity.Plastic deformation is detected under higher applied load and sliding velocities.
基金The National Natural Science Foundation of China(No.60773217)Free Exploration Project(985 Project of Renmin University of China)(No.21361231)
文摘In order to enable quality-aware web services selection in the process of service composition,this paper first describes the non-functional requirements of service consumers and the quality of elementary service or composite service as a quality vector,and then models the QoS(quality of service)-aware composition as a multiple criteria optimization problem in extending directed graph.A novel simulated annealing algorithm for QoS-aware web services composition is presented.A normalizing for composite service QoS values is made,and a secondary iterative optimization is used in the algorithm.Experimental results show that the simulated annealing algorithm can satisfy the multiple criteria and global QoS requirements of service consumers.The algorithm produces near optimum solution with much less computation cost.
基金Supported by Forestry Science and Technology Planning Program(XLK201406)~~
文摘ln order to discuss the optimum seedling density of Toona ciliate, different seedling densities were studied. The results showed that seeding height and basal diameter decreased and quality of the seedlings declined with the increase of seedling density. The reasonable density of seedlings is key to cultivate high-quality seedlings and achieve the best seedling efficiency. The optimum density was 30 plants/m2 for the first class seedlings of biennial seedlings, and the optimum density of l and ll seedlings for production afforestation was 40 plants/m2.
基金Projects(2013BAB02B03,2012BAB08B00)supported by the National Science and Technology Support Program of ChinaProject(51074177)supported by the Joint Funding of National Natural Science Foundation and Shanghai Baosteel Group CorporationProjects(51274254,51322403)supported by the National Natural Science Foundation of China
文摘According to the actual conditions in Sanshandao Gold Mine, the cancelling ore pillars mining method was researched. Firstly, a series of tests for the physical and mechanical characteristics of rock mass were carried out and a quality classification system of rock mass applied in coastal metal deposit was established. Secondly, the reasonable demarcation depth of cancelling ore pillars was simulated using the finite element method, and the simulation results show that the ore pillars can be cancelled below the level of-555 m. Thirdly, a novel layer-backfill mining method of room-pillar alternation was designed to reduce the disturbance and settlement of terrain in mining area. Engineering practice shows that the new mining method enhanced the mining output and relieved rock disturbance. Furthermore, the settlement of the roof strata was small and no disaster occurred. The new mining technology effectively controlled the deformation of the terrain, indicating that the mining of the large-scale gold coastal deposit in Sanshandao Gold Mine was achieved safely, efficiently, and with a low loss rate.
文摘Based on the analysis of monitoring data on six pollution indexes of SO2, NO2, CO, O3, PM10 and PM2.5 from 53 monitoring points in 7 cities, including Beijing, Tianjin, Shijiazhuang, etc., from April 8 of 2014 to July 23 of 2014, this article adopted Pearson correlation coefficient method to determine the relevance among each pollutant of these cities with the help of SPSS. The results showed that such three leading indexes as SO2, PM10 and PM2.5 had strong correlation in Beijing, Tianjin and main cities of Hebei. Finally, some suggestions and preventive measures for the cooperative governance of air pollution in Beijing-Tianjin-Hebei Region were put forward, hoping this can help them.
文摘The functional fractions (acid, basic, amphoteric and neutral fractions) are isolated from the Liaohe Du-84 heavy crude oil and Shengli Gudao Kenxi heavy crude oil by ion-exchange chromatography, but the conventional fractions (saturates, aromatics, resins and asphaltenes) are also isolated from the heavy crude oil. These components have been characterized by spectroscopic methods (FT-IR), namely acid number, basic nitrogen number, ultimate analysis and molecular weight measurements using vapor pressure osmometry (VPO). The ion-exchange chromatography method based on separation by a functional group induces a little change on the nature of the crudes and reasonable mass balances can be easily obtained.
文摘The utilization and changes of forest resources were studied in the Lishuihe Forest Bureau. Based on remote sensing images in 1985 and 1999, changes of major forest resources were analyzed by statistical and overlap method and classified quantitatively. The results showed that in recent 15 years, logging spots and man-made young forest changed violently, which was due to human activities. Different forest management manners and harvesting intensity played an important role in forest resources change. Dongsheng and Xilinhe tree farms were typical cases of different forest status and management for the Bu-reau, where forest succession was intervened by either human or natural disturbance. Dongsheng Tree Farm underwent a light harvest intensity and maintained a unit stock volume of 536.27 m3hm-2, as much as that of broadleaf/Korean pine forest of Changbai Mountain Natural Reserve; Xilinhe Tree Farm underwent an intense harvest and was composed of secondary forests, where mature forests just had a small percentage and the unit stock volume was low. The study was useful to guide future forest management. What抯 more, problems found in the research were also analyzed and reasonable advice was given to the local forest management.
文摘[Objective]The aim of this study was to set up a high performance liquid chromatography for rapid determination of isoflavones from soybean and analyze the correlation between isofalvone content and protein or fat content. [Method]The isoflavones were firstly extracted by 80% methanol and then hydrolyzed at 100 ℃. The chromatographic separation adopted a reversed-phase C18 analytical column with binary high-pressure gradient elution,while its analysis time was 25 min and column temperature was 40 ℃. The diode array detector was used for monitoring with wavelength of 260 nm. The correlation between isofalvone content and protein or fat content was analyzed by data processing system Origin 6.0. [Result]The high performance liquid chromatograph for determination of isoflavones from soybean was verified to be accurate and reliable by methodology. The isoflavones of 85 soybean lines cultivated in Jilin Province were determined,and the results primarily showed the characters and ranges of isoflavones from soybean lines cultivated in Jilin Province,while the isoflavone content of soybeans ranged from 2.29 to 4.89 mg/g,and the average content was 3.36 mg/g. The isoflavone content of 5 soybean lines exceeded 4 mg/g,while there was a remarkably negative correlation between isoflavone content and protein content,and there was no significant positive correlation between isoflavone content and fat content. [Conclusion]The isoflavone content of soybean lines cultivated in Jilin Province is higher,so it is feasible for breeding the soybean lines with high isoflavone content and fat contetnt.
文摘[Objective] The paper is to construct the logistics tracking management system of tropical agricultural products based on supply chain.[Method] With tropical agricultural products in Hainan as study object,based on logistics supply chain files and electronic tag coding of agricultural products,cold chain temperature and humidity monitoring,vehicle transportation positioning,data exchange of XML Web services and role-based permission dynamic allocation,the multi-level multi-permission and multi-role logistics tracking management system of tropical agricultural products has been established.[Result] The system constructs information exchange platform for various links of logistics supply chain of tropical agricultural products,which realizes the entire quality monitoring and information tracing of agricultural products,thus enhancing the competitiveness of supply chain in company.[Conclusion] The system has good application and extension prospect.