Citrate, oxalate, tartrate and malate were added into soils during the growthperiod of ryegrass to study the effect of different organic ligands on the release of variousinorganic P (Pi) fractions in a yellow-brown so...Citrate, oxalate, tartrate and malate were added into soils during the growthperiod of ryegrass to study the effect of different organic ligands on the release of variousinorganic P (Pi) fractions in a yellow-brown soil and a paddy soil. The results showed that oxalatewas most effective in promoting the release of total Pi in the yellow-brown soil and tartrate in thepaddy soil. The dominant Pi fractions released from the yellow-brown soil were calcium phosphate(Ca-P) and aluminum phosphate (Al-P) and those from the paddy soil were iron phosphate (Fe-P) andreductant soluble phosphate (O-P) mobilized by tartrate. Phosphorous-mobilizing capability oforganic acids in the yellow-brown soil revealed the following order: oxalate > citrate > malate >tartrate. In the paddy soil, the order was tartrate > citrate ≈ oxalate > malate. It wasdemonstrated that organic ligands were different in their capabilities of mobilizing Pi and the sameorganic ligand showed also a discrepancy in mobilizing P in different soils. Although the additionof organic ligands into soils could increase the amount of P taken up by ryegrass, the more uptakeof P, however, was not only due to the more release of Pi, but also partly from organic P. In manycases, organic ligands promoted the release of the total Pi, while different fractions showeddifferent trends: some increased and others decreased.展开更多
Background The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging. Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissu...Background The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging. Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissue structure at molecular level. This study was designed to determine the value of DWI in the diagnosis of diffuse liver lesions in early stage. Methods Diffuse liver lesions were induced by diethylnitrosamine in 42 rats of test group. Fourteen rats in control group were fed with pure water. Dynamic changes of MR DWI were observed every week in both groups during the early stage of diffuse liver lesions (1 to 12 weeks after drug administration in the test group). Apparent diffusion coefficient (ADC) values of liver parenchyma in different stages and pathologic changes were analyzed. Results The process of diffuse hepatic lesions in the test group was classified into three stages according to pathological changes, namely hepatitis, hepatic fibrosis and cirrhosis. No obvious morphological changes were shown by conventional imaging in both groups during this stage. But MR DWI demonstrated heterogeneous signal changes in early stage of hepatic cirrhosis in the test group. No significant change of ADC values was found in the control group between different weeks ( P >0.05). The ADC values of the test group declined from the fifth week, and after the tenth week the ADC values were significantly different between the test and control groups at gradient factor (b) value 300 sec/mm 2 ( P <0.05). At b value 600 and 1000 sec/mm 2, significant difference was seen between the two groups from the sixth week onward. The range of ADC value of the groups was (1.7-0.9)±(0.40-0.04) mm 2/sec (b=600) and (1.38-0.75)±(0.07-0.35) mm 2/sec (b=1000), respectively. Dominant pathological changes included swelled hepatocytes within 1 to 4 weeks after the administration of diethylnitrosamine in the test group, hyperplasia of fibrous tissues in 5-8 weeks and formation of cirrhotic nodules in 9-12 weeks. Conclusions 展开更多
Black rockfish(Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process...Black rockfish(Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process of germ cells in this ovoviviparous rockfish in reproductive season(October 2011–November 2012) with histological methods. We found that the gonad of mature fish showed notable seasonal changes in developmental characteristics and morphological structure. The sperm cells matured during a period lasting from October to December, significantly earlier than the oocytes did. A large number of spermatozoa and other cells occurred in testis at different developmental stages. Vitellogenesis in oocytes began in October, and gestation appeared in April next year. Spermatophores were discovered for the first time in Sebastes, which assembled in testis, main sperm duct, oviduct and genital tract, as well as ovarian cavity in October and April. These organs may serve either as production or hiding places for spermatophores and spermatozoa which were stored and transported in form of spermatophores. Testicular degeneration started from the distal part of testis in April, with spermatophores assembled in degenerating testis and waiting for transportation. The copulation probably lasted for a long period, during which the spermatozoa were discharged in batches as spermatophores. These spermatophores were coated with sticky materials secreted from the interstitial areas of testis and the main sperm duct, then transported into ovary.展开更多
Knowledge graph(KG)serves as a specialized semantic network that encapsulates intricate relationships among real-world entities within a structured framework.This framework facilitates a transformation in information ...Knowledge graph(KG)serves as a specialized semantic network that encapsulates intricate relationships among real-world entities within a structured framework.This framework facilitates a transformation in information retrieval,transitioning it from mere string matching to far more sophisticated entity matching.In this transformative process,the advancement of artificial intelligence and intelligent information services is invigorated.Meanwhile,the role ofmachine learningmethod in the construction of KG is important,and these techniques have already achieved initial success.This article embarks on a comprehensive journey through the last strides in the field of KG via machine learning.With a profound amalgamation of cutting-edge research in machine learning,this article undertakes a systematical exploration of KG construction methods in three distinct phases:entity learning,ontology learning,and knowledge reasoning.Especially,a meticulous dissection of machine learningdriven algorithms is conducted,spotlighting their contributions to critical facets such as entity extraction,relation extraction,entity linking,and link prediction.Moreover,this article also provides an analysis of the unresolved challenges and emerging trajectories that beckon within the expansive application of machine learning-fueled,large-scale KG construction.展开更多
Comprehensive Summary A visible-light mediated exclusively regioselective synthesis of 2,2-disubstituted thio-functionalized tetrahydrofurans,tetrahydro-pyrans and oxepanes has been described through an operationally ...Comprehensive Summary A visible-light mediated exclusively regioselective synthesis of 2,2-disubstituted thio-functionalized tetrahydrofurans,tetrahydro-pyrans and oxepanes has been described through an operationally simple and mild photoredox protocol.Thiyl radical generated from N-phenylsulfenyl phthalimide by photoredox catalysis was proven to be the key reactive intermediate in this reaction.展开更多
Horizontal feeding devices and plate hob chopping devices are the key component of silage maize harvester.To solve the problem of feeding blockage,reduce energy consumption,and improve the chopping quality of the chop...Horizontal feeding devices and plate hob chopping devices are the key component of silage maize harvester.To solve the problem of feeding blockage,reduce energy consumption,and improve the chopping quality of the chopping device a horizontal different diameter five-rollers device(HDDFD)was designed and the plate hob chopping device was simultaneously optimized and analyzed.Through the dynamic analysis,the feeding conveying speed was determined to be 2.0-4.5 m/s.The distance equation of the actual and theoretical cutting-edge curve and the position of the fixed blade were finally obtained.Single factor and response surface orthogonal tests in the bench site were carried out with feeding speed,rotating speed of chopping cylinder,feeding amount,and feeding direction as influencing factors,standard grass length rate(SGLR),and energy consumption per unit mass(ECPUM)as evaluation indexes.The optimal working parameters for chopping performance could be concluded as a feeding speed of 3.39 m/s,rotating speed of the chopping cylinder of 1016.17 r/min,feeding amount of 8.04 kg/s,and feeding direction of 52.2°.In addition,the SGLR and ECPUM were obtained as 95.35%and 37.63 kJ/kg,respectively.The relative error between the experimental results with round parameter combination and the predicted value was verified to be less than 5%.Field tests verified the reliability of the optimized feeding and chopping device.It can be seen that the HDDFD and optimized plate hob chopping device can meet the requirements of mechanized silage harvesting which obviously improves the working quality and reduce the energy consumption of chopping.展开更多
In the era of big data,E-commerce plays an increasingly important role,and steel E-commerce certainly occupies a positive position.However,it is very difficult to choose satisfactory steel raw materials from diverse s...In the era of big data,E-commerce plays an increasingly important role,and steel E-commerce certainly occupies a positive position.However,it is very difficult to choose satisfactory steel raw materials from diverse steel commodities online on steel E-commerce platforms in the purchase of staffs.In order to improve the efficiency of purchasers searching for commodities on the steel E-commerce platforms,we propose a novel deep learning-based loss function for named entity recognition(NER).Considering the impacts of small sample and imbalanced data,in our NER scheme,the focal loss,the label smoothing,and the cross entropy are incorporated into a lite bidirectional encoder representations from transformers(BERT)model to avoid the over-fitting.Moreover,through the analysis of different classic annotation techniques used to tag data,an ideal one is chosen for the training model in our proposed scheme.Experiments are conducted on Chinese steel E-commerce datasets.The experimental results show that the training time of a lite BERT(ALBERT)-based method is much shorter than that of BERT-based models,while achieving the similar computational performance in terms of metrics precision,recall,and F1 with BERT-based models.Meanwhile,our proposed approach performs much better than that of combining Word2Vec,bidirectional long short-term memory(Bi-LSTM),and conditional random field(CRF)models,in consideration of training time and F1.展开更多
Capacity holding the second place in the world Meta-oriented aromatic polyamide fiber was first developed by DuPont of the United States, Commercial production began in the late 1960s, Today the world’s capacity to p...Capacity holding the second place in the world Meta-oriented aromatic polyamide fiber was first developed by DuPont of the United States, Commercial production began in the late 1960s, Today the world’s capacity to produce meta-oriented aromatic polyamide fiber is 28 150 t/a, and DuPont holds a 78% market share.展开更多
Satellite-derived surface temperature data is increasingly required to supplement the limited weather stations for the assessment of temperature trend over the data-sparse Antarctic Ice Sheet. To accomplish this, it i...Satellite-derived surface temperature data is increasingly required to supplement the limited weather stations for the assessment of temperature trend over the data-sparse Antarctic Ice Sheet. To accomplish this, it is essential to assess the relationship and difference between satellite-based land-surface temperature (LST) retrieval and air temperature observation. In this study, we made a comparison between monthly averaged LST from Moderate Resolution Imaging Spectroradiometer (MODIS) and the corresponding air temperature at the nominal heights of 1 m and 2 m from automatic weather stations (AWSs) over the Lambert Glacier basin, East Antarctica. This comparison reveals a statistically significant correlation between the two types of temperature measurements with correlation coefficient (R) above 0.6. Also, the time difference between satellite overpass and air temperature observation is not critical for the R values. Although MODIS LST evidently deviates from air temperature (Mean difference fluctuates from 2.87°C to 8.08°C) probably due to the temperature inversion effect, heterogeneity in surface emissivity, representative of AWS measurements and satellite self limitation. MODIS LST measurements have a great potential for the accurate evaluation or monitoring of regional air temperature over Antarctica, and thus better improve current reconstruction of spatial and temporal reconstruction variability in Antarctic temperature.展开更多
基金Project supported by the National Key Basic Research Support Foundation (NKBRSF) of China (No.G1999011806).
文摘Citrate, oxalate, tartrate and malate were added into soils during the growthperiod of ryegrass to study the effect of different organic ligands on the release of variousinorganic P (Pi) fractions in a yellow-brown soil and a paddy soil. The results showed that oxalatewas most effective in promoting the release of total Pi in the yellow-brown soil and tartrate in thepaddy soil. The dominant Pi fractions released from the yellow-brown soil were calcium phosphate(Ca-P) and aluminum phosphate (Al-P) and those from the paddy soil were iron phosphate (Fe-P) andreductant soluble phosphate (O-P) mobilized by tartrate. Phosphorous-mobilizing capability oforganic acids in the yellow-brown soil revealed the following order: oxalate > citrate > malate >tartrate. In the paddy soil, the order was tartrate > citrate ≈ oxalate > malate. It wasdemonstrated that organic ligands were different in their capabilities of mobilizing Pi and the sameorganic ligand showed also a discrepancy in mobilizing P in different soils. Although the additionof organic ligands into soils could increase the amount of P taken up by ryegrass, the more uptakeof P, however, was not only due to the more release of Pi, but also partly from organic P. In manycases, organic ligands promoted the release of the total Pi, while different fractions showeddifferent trends: some increased and others decreased.
文摘Background The diagnosis of diffuse hepatic lesions in early stage is a tough task at any time for clinical conventional imaging. Magnetic resonance diffusion-weighted imaging (MR DWI) can detect the changes of tissue structure at molecular level. This study was designed to determine the value of DWI in the diagnosis of diffuse liver lesions in early stage. Methods Diffuse liver lesions were induced by diethylnitrosamine in 42 rats of test group. Fourteen rats in control group were fed with pure water. Dynamic changes of MR DWI were observed every week in both groups during the early stage of diffuse liver lesions (1 to 12 weeks after drug administration in the test group). Apparent diffusion coefficient (ADC) values of liver parenchyma in different stages and pathologic changes were analyzed. Results The process of diffuse hepatic lesions in the test group was classified into three stages according to pathological changes, namely hepatitis, hepatic fibrosis and cirrhosis. No obvious morphological changes were shown by conventional imaging in both groups during this stage. But MR DWI demonstrated heterogeneous signal changes in early stage of hepatic cirrhosis in the test group. No significant change of ADC values was found in the control group between different weeks ( P >0.05). The ADC values of the test group declined from the fifth week, and after the tenth week the ADC values were significantly different between the test and control groups at gradient factor (b) value 300 sec/mm 2 ( P <0.05). At b value 600 and 1000 sec/mm 2, significant difference was seen between the two groups from the sixth week onward. The range of ADC value of the groups was (1.7-0.9)±(0.40-0.04) mm 2/sec (b=600) and (1.38-0.75)±(0.07-0.35) mm 2/sec (b=1000), respectively. Dominant pathological changes included swelled hepatocytes within 1 to 4 weeks after the administration of diethylnitrosamine in the test group, hyperplasia of fibrous tissues in 5-8 weeks and formation of cirrhotic nodules in 9-12 weeks. Conclusions
基金supported financially by Grand Innovating Program of Agriculture Applying Technique in Shandong Province (No. 2008-109)Modern Agricultural Industry Technology System in Shandong Province and the Science and Technology Development Program of Yantai (No. 2013 ZH088)
文摘Black rockfish(Sebastes schlegeli) is an important species for culture; however, its reproductive characteristics have not been fully documented. In this study, we investigated the morphology and developmental process of germ cells in this ovoviviparous rockfish in reproductive season(October 2011–November 2012) with histological methods. We found that the gonad of mature fish showed notable seasonal changes in developmental characteristics and morphological structure. The sperm cells matured during a period lasting from October to December, significantly earlier than the oocytes did. A large number of spermatozoa and other cells occurred in testis at different developmental stages. Vitellogenesis in oocytes began in October, and gestation appeared in April next year. Spermatophores were discovered for the first time in Sebastes, which assembled in testis, main sperm duct, oviduct and genital tract, as well as ovarian cavity in October and April. These organs may serve either as production or hiding places for spermatophores and spermatozoa which were stored and transported in form of spermatophores. Testicular degeneration started from the distal part of testis in April, with spermatophores assembled in degenerating testis and waiting for transportation. The copulation probably lasted for a long period, during which the spermatozoa were discharged in batches as spermatophores. These spermatophores were coated with sticky materials secreted from the interstitial areas of testis and the main sperm duct, then transported into ovary.
基金supported in part by the Beijing Natural Science Foundation under Grants L211020 and M21032in part by the National Natural Science Foundation of China under Grants U1836106 and 62271045in part by the Scientific and Technological Innovation Foundation of Foshan under Grants BK21BF001 and BK20BF010。
文摘Knowledge graph(KG)serves as a specialized semantic network that encapsulates intricate relationships among real-world entities within a structured framework.This framework facilitates a transformation in information retrieval,transitioning it from mere string matching to far more sophisticated entity matching.In this transformative process,the advancement of artificial intelligence and intelligent information services is invigorated.Meanwhile,the role ofmachine learningmethod in the construction of KG is important,and these techniques have already achieved initial success.This article embarks on a comprehensive journey through the last strides in the field of KG via machine learning.With a profound amalgamation of cutting-edge research in machine learning,this article undertakes a systematical exploration of KG construction methods in three distinct phases:entity learning,ontology learning,and knowledge reasoning.Especially,a meticulous dissection of machine learningdriven algorithms is conducted,spotlighting their contributions to critical facets such as entity extraction,relation extraction,entity linking,and link prediction.Moreover,this article also provides an analysis of the unresolved challenges and emerging trajectories that beckon within the expansive application of machine learning-fueled,large-scale KG construction.
基金the National Natural Science Foundation of China(22171177,51973107)the Chemistry and Chemical Engineering Guangdong Laboratory(1922003)+1 种基金the Guangdong Major Project of Basic and Applied Basic Research(2019B030302009)the Guangdong Province Universities and Colleges Pearl River Scholar Funded Scheme2019(GDUPS2019).
文摘Comprehensive Summary A visible-light mediated exclusively regioselective synthesis of 2,2-disubstituted thio-functionalized tetrahydrofurans,tetrahydro-pyrans and oxepanes has been described through an operationally simple and mild photoredox protocol.Thiyl radical generated from N-phenylsulfenyl phthalimide by photoredox catalysis was proven to be the key reactive intermediate in this reaction.
基金The research program is supported by the Key Science and Technology Innovation Project of Shandong Province,China(Grant No.2019JZZY020615)the Shandong Province Agricultural major application technology innovation project(Grant No.SD2019NJ005).
文摘Horizontal feeding devices and plate hob chopping devices are the key component of silage maize harvester.To solve the problem of feeding blockage,reduce energy consumption,and improve the chopping quality of the chopping device a horizontal different diameter five-rollers device(HDDFD)was designed and the plate hob chopping device was simultaneously optimized and analyzed.Through the dynamic analysis,the feeding conveying speed was determined to be 2.0-4.5 m/s.The distance equation of the actual and theoretical cutting-edge curve and the position of the fixed blade were finally obtained.Single factor and response surface orthogonal tests in the bench site were carried out with feeding speed,rotating speed of chopping cylinder,feeding amount,and feeding direction as influencing factors,standard grass length rate(SGLR),and energy consumption per unit mass(ECPUM)as evaluation indexes.The optimal working parameters for chopping performance could be concluded as a feeding speed of 3.39 m/s,rotating speed of the chopping cylinder of 1016.17 r/min,feeding amount of 8.04 kg/s,and feeding direction of 52.2°.In addition,the SGLR and ECPUM were obtained as 95.35%and 37.63 kJ/kg,respectively.The relative error between the experimental results with round parameter combination and the predicted value was verified to be less than 5%.Field tests verified the reliability of the optimized feeding and chopping device.It can be seen that the HDDFD and optimized plate hob chopping device can meet the requirements of mechanized silage harvesting which obviously improves the working quality and reduce the energy consumption of chopping.
基金This work was supported in part by the National Natural Science Foundation of China under Grants U1836106 and 81961138010in part by the Beijing Natural Science Foundation under Grants M21032 and 19L2029+2 种基金in part by the Beijing Intelligent Logistics System Collaborative Innovation Center under Grant BILSCIC-2019KF-08in part by the Scientific and Technological Innovation Foundation of Shunde Graduate School,USTB,under Grants BK20BF010 and BK19BF006in part by the Fundamental Research Funds for the University of Science and Technology Beijing under Grant FRF-BD-19-012A.
文摘In the era of big data,E-commerce plays an increasingly important role,and steel E-commerce certainly occupies a positive position.However,it is very difficult to choose satisfactory steel raw materials from diverse steel commodities online on steel E-commerce platforms in the purchase of staffs.In order to improve the efficiency of purchasers searching for commodities on the steel E-commerce platforms,we propose a novel deep learning-based loss function for named entity recognition(NER).Considering the impacts of small sample and imbalanced data,in our NER scheme,the focal loss,the label smoothing,and the cross entropy are incorporated into a lite bidirectional encoder representations from transformers(BERT)model to avoid the over-fitting.Moreover,through the analysis of different classic annotation techniques used to tag data,an ideal one is chosen for the training model in our proposed scheme.Experiments are conducted on Chinese steel E-commerce datasets.The experimental results show that the training time of a lite BERT(ALBERT)-based method is much shorter than that of BERT-based models,while achieving the similar computational performance in terms of metrics precision,recall,and F1 with BERT-based models.Meanwhile,our proposed approach performs much better than that of combining Word2Vec,bidirectional long short-term memory(Bi-LSTM),and conditional random field(CRF)models,in consideration of training time and F1.
文摘Capacity holding the second place in the world Meta-oriented aromatic polyamide fiber was first developed by DuPont of the United States, Commercial production began in the late 1960s, Today the world’s capacity to produce meta-oriented aromatic polyamide fiber is 28 150 t/a, and DuPont holds a 78% market share.
文摘Satellite-derived surface temperature data is increasingly required to supplement the limited weather stations for the assessment of temperature trend over the data-sparse Antarctic Ice Sheet. To accomplish this, it is essential to assess the relationship and difference between satellite-based land-surface temperature (LST) retrieval and air temperature observation. In this study, we made a comparison between monthly averaged LST from Moderate Resolution Imaging Spectroradiometer (MODIS) and the corresponding air temperature at the nominal heights of 1 m and 2 m from automatic weather stations (AWSs) over the Lambert Glacier basin, East Antarctica. This comparison reveals a statistically significant correlation between the two types of temperature measurements with correlation coefficient (R) above 0.6. Also, the time difference between satellite overpass and air temperature observation is not critical for the R values. Although MODIS LST evidently deviates from air temperature (Mean difference fluctuates from 2.87°C to 8.08°C) probably due to the temperature inversion effect, heterogeneity in surface emissivity, representative of AWS measurements and satellite self limitation. MODIS LST measurements have a great potential for the accurate evaluation or monitoring of regional air temperature over Antarctica, and thus better improve current reconstruction of spatial and temporal reconstruction variability in Antarctic temperature.
