Designing a high-fidelity cutting device is one of the difficulties in hydrate samples pressure-holding transfer.Due to the limitations of the existing mechanical system,there is much damage to the cut surface of hydr...Designing a high-fidelity cutting device is one of the difficulties in hydrate samples pressure-holding transfer.Due to the limitations of the existing mechanical system,there is much damage to the cut surface of hydrate samples,with many chips produced,which seriously affects the quality of samples.In this paper,a new cutting device utilizes two servo motors to achieve a high degree of automation.Using the Archimedes spiral,it achieves low disturbance of the cut surface and provides accurate control of the process.In addition,due to the operation of the sample long-stroke push unit,cutting hydrate samples of any length with almost no chips within a short cutting time can be achieved.Laboratory and sea tests have achieved all design requirements of the equipment and strongly demonstrate its benefit and stability.It is concluded that this new high-fidelity cutting technology is practically efficient.The physical state of the hydrate can be maintained to the greatest extent,and thus the new equipment provides significant support for the exploration and development of hydrate resources.展开更多
Soritia leptalina endangers mainly Quercus aquifolioides, and it became particularly rampant on Q. aquifolioides in Linzhi area, Tibet. By applying field investigation and lab analysis, this study explored the spatial...Soritia leptalina endangers mainly Quercus aquifolioides, and it became particularly rampant on Q. aquifolioides in Linzhi area, Tibet. By applying field investigation and lab analysis, this study explored the spatial distribution type and sampling technology of S. leptalina larvae on Q. aquifolioides. The results showed that insect density in the upper layer of tree canopy is higher than that in the middle and lower layer,that in the upper, middle and lower layer of different levels varies greatly, and insect density in different directions follows the sequence: east > north > west > south; spatial distribution of S. leptalina on Q.aquifolioides belongs to aggregation type, larvae show mutual repulsion; aggregation of S. leptalina is the result of biological characteristics of its larvae and the habitat environment; taking Iwa regression model as the basis, the optimal sampling quantity is determined. The study disclosed the spatial distribution rules of S.leptalina on Q. aquifolioides, and on the basis of which could provide the theoretical basis for preventing Q.aquifolioides from the damage of S. leptalina, and also scientific support for studying the spatial distribution pattern of this insect and its natural enemies on other hosts.展开更多
The core sampling experiments were conducted after hydraulic fracturing in the three-dimensional development zone of Fuling shale gas.Six coring wells of different well types were systematically designed.Based on the ...The core sampling experiments were conducted after hydraulic fracturing in the three-dimensional development zone of Fuling shale gas.Six coring wells of different well types were systematically designed.Based on the integrated engineering technology of post-fracturing drilling,coring and monitoring of shale and the analysis of fracture source tracing,the evaluation of the fracture network after fracturing in the three-dimensional development of shale gas was conducted.The data of core fractures after fracturing indicate that three major types of fractures are formed after fracturing:natural fractures,hydraulic fractures,and fractures induced by external mechanical force,which are further classified into six subcategories:natural structural fractures,natural bedding fractures,hydraulic fractures,hydraulically activated fractures,drilling induced fractures,and fractures induced by core transportation.The forms of the artificial fracture network after fracturing are complex.Hydraulic fractures and hydraulically activated fractures interweave with each other,presenting eight forms of artificial fracture networks,among which the“一”-shaped fracture is the most common,accounting for approximately 70%of the total fractures.When the distance to the fractured wellbore is less than 35 m,the density of the artificial fracture network is relatively high;when it is 35–100 m,the density is lower;and when it is beyond 100 m,the density gradually increases.The results of the fracture tracing in the core sampling area confirm that the current fracturing technology can essentially achieve the differential transformation of the reservoir in the main area of Jiaoshiba block in Fuling.The three-layer three-dimensional development model can efficiently utilize shale gas reserves,although there is still room for improvement in the complexity and propagation uniformity of fractures.It is necessary to further optimize technologies such as close-cutting combined with temporary blocking and deflection within fractures or at fracture mouths,as well as limited flow perforation techniques,to promote the balanced initiation and extension of fractures.展开更多
Management strategies and the use of advanced technologies are equally important for determining the sample number and sampling frame for successful field sampling for animal disease prevalence studies.The quality of ...Management strategies and the use of advanced technologies are equally important for determining the sample number and sampling frame for successful field sampling for animal disease prevalence studies.The quality of the biological samples collected in the field has a direct bearing on the integrity of the data generated,prevalence estimates and subsequent policy decisions on disease control.Hence,compromising the quality of biological samples collected in the field could potentially undermine the priority setting principles in disease control strategies.Biological samples collected from domestic animals in the field are precious materials and require meticulous planning for sample collection,sample storage in the field,transportation,and storage in the laboratory.Poorly managed field sampling has a significant detrimental impact on the sample quality and quantity and directly affects the accuracy of disease prevalence data.A bad choice of sampling tools,containers,storage and transport all have a negative impact on the integrity of the sample and consequently have an impact on the outcome.Over the last two years,as part of our one health animal sampling work in ndia,we have observed challenges and opportunities in the field sampling of animals for disease prevalence studies.This paper aims to provide information on management practices and technologies for efficient biological sample collection from the field and ensure that good quality samples are available fortesting.展开更多
This article reviews Mars sampling and return technology,by retrieving and analyzing the patents of domestic and foreign sampling equipment and mechanism technology,Mars surface removal technology and ultra-highspeed ...This article reviews Mars sampling and return technology,by retrieving and analyzing the patents of domestic and foreign sampling equipment and mechanism technology,Mars surface removal technology and ultra-highspeed light and small sample return technology.It conducts patent analysis from the macro-technical view down to the micro-specific content view using statistical,quantitative and qualitative analysis methods.In the process of macro-analysis,it analyzes patent data from multiple perspectives such as time,region,technical composition,and applicants,and establishes the development trends for Mars sampling and return technology at home and abroad.In the process of micro-analysis,through the analysis and interpretation of key patents,we can learn the development priorities and development direction of foreign Mars sampling and return technology.This paper also proposes China’s Mars sampling and return technology development suggestions.展开更多
With the appearance of novel radar signal with low intercept probability, the bandwidth of radar receiver is wider and wider. Wideband digital receiver becomes a research hotspot in the field of communication...With the appearance of novel radar signal with low intercept probability, the bandwidth of radar receiver is wider and wider. Wideband digital receiver becomes a research hotspot in the field of communication, radar and electronic reconnaissance, etc. As one of wideband digital receiver systems, digital channelized receiver has become a research emphasis due to the characteristics of full probability receiving and processing multiple signals. Digital channelized technology and signal sampling theory are deeply studied and an efficient channelized model is derived based on filter banks. The correctness of the model is verified by computer simulation The model has less computation compared with the traditional model, which is suitable for engineering application展开更多
This study examines the impact of farmers’cooperatives participation and technology adoption on their economic welfare in China.A double selectivity model(DSM)is applied to correct for sample selection bias stemming ...This study examines the impact of farmers’cooperatives participation and technology adoption on their economic welfare in China.A double selectivity model(DSM)is applied to correct for sample selection bias stemming from both observed and unobserved factors,and a propensity score matching(PSM)method is applied to calculate the agricultural income difference with counter factual analysis using survey data from 396 farmers in 15 provinces in China.The findings indicate that farmers who join farmer cooperatives and adopt agricultural technology can increase agricultural income by 2.77 and 2.35%,respectively,compared with those non-participants and non-adopters.Interestingly,the effect on agricultural income is found to be more significant for the low-income farmers than the high-income ones,with income increasing 5.45 and 4.51%when participating in farmer cooperatives and adopting agricultural technology,respectively.Our findings highlight the positive role of farmer cooperatives and agricultural technology in promoting farmers’economic welfare.Based on the findings,government policy implications are also discussed.展开更多
Objective:To present an integrated molecular biology dedicated system for tuberculosis diagnosis.Methods:One hundred and five sputum specimens from patients strongly suspected by clinical parameters of tuberculosis we...Objective:To present an integrated molecular biology dedicated system for tuberculosis diagnosis.Methods:One hundred and five sputum specimens from patients strongly suspected by clinical parameters of tuberculosis were studied by Ziehl-Neelsen staining,by cultivation on solid medium and by a balanced hemincsted fluorometric PCR system(Orange C3TB) that could preserve worker safety and produce a rather pure material free of potential inhibitors. DNA amplification was performed in a low cost tuberculosis termocycler-fluorotneter.Produced double stranded DNA was flurometrically detected.The whole reaction was conducted in one single tube which would not be opened after adding the processed sample in order to minimize the risk of cross contamination with amplicons.Results:The assay was able to delect 30 bacillus per sample mL with 99.8%interassay variation coefficient.PCR was positive in 23(21.9%) tested samples(21 of them were smear negative).In our study it showed a preliminary sensitivity of 94.5%for sputum and an overall specificity of 98.7%.Conclusions:Total run time of the test is 4 h with 2.5 real working time.All PCR positive samples are also positive by microbiological culture and clinical criteria.Results show that it could be a very useful tool to increase detection efficiency of tuberculosis disease in low bacilus load samples.Furthermore,its low cost and friendly using make it feasible to run in poor regions.展开更多
Objective:To surveill emerging variants by nanopore technology-based genome sequencing in different COVID-19 waves in Sri Lanka and to examine the association with the sample characteristics,and vaccination status.Met...Objective:To surveill emerging variants by nanopore technology-based genome sequencing in different COVID-19 waves in Sri Lanka and to examine the association with the sample characteristics,and vaccination status.Methods:The study analyzed 207 RNA positive swab samples received to sequence laboratory during different waves.The N gene cut-off threshold of less than 30 was considered as the major inclusion criteria.Viral RNA was extracted,and elutes were subjected to nanopore sequencing.All the sequencing data were uploaded in the publicly accessible database,GISAID.Results:The Omicron,Delta and Alpha variants accounted for 58%,22%and 4%of the variants throughout the period.Less than 1%were Kappa variant and 16%of the study samples remained unassigned.Omicron variant was circulated among all age groups and in all the provinces.Ct value and variants assigned percentage was 100%in Ct values of 10-15 while only 45%assigned Ct value over 25.Conclusions:The present study examined the emergence,prevalence,and distribution of SARS-CoV-2 variants locally and has shown that nanopore technology-based genome sequencing enables whole genome sequencing in a low resource setting country.展开更多
Ultrafast optoelectronic technology has been widely used in terahertz time domain spectrum,terahertz imaging technology,terahertz communication and so on,and great progress has been achieved in the past two decade.Rec...Ultrafast optoelectronic technology has been widely used in terahertz time domain spectrum,terahertz imaging technology,terahertz communication and so on,and great progress has been achieved in the past two decade.Recently,this innovative technology has been applied in radio metrology and supplied a potential and hopeful method to solve the existent challenges of calibration devices and equipments with bandwidth up to 100 GHz.This paper generally summarizes the emerging applications of the ultrafast optoelectronic technology in radio metrology.The main applications of this technology in calibrating broadband sampling oscilloscopes,the high-speed photodiodes and calibrating the electrical pulse generators are emphasized,and the testing of monolithic microwave integrated circuits is also presented.展开更多
To ensure the quality and safety of pure milk,detection method of typical preservative-potassium sorbate in milk was researched in this paper.Hyperspectral imaging technology was applied to realize rapid detection.Inf...To ensure the quality and safety of pure milk,detection method of typical preservative-potassium sorbate in milk was researched in this paper.Hyperspectral imaging technology was applied to realize rapid detection.Influence factors for hyperspectral data collection for milk samples were firstly researched,including height of sample,bottom color and sample filled up container or not.Pretreatment methods and variable selection algorithms were applied into original spectral data.Rapid detection models were built based on support vector machine method(SVM).Finally,standard normalized variable(SNV)-competitive adaptive reweighted sampling(CARS)and SVM model was chosen in this paper.The accuracies of calibration set and testing set were 0.97 and 0.97,respectively.Kappa coefficient of the model was 0.93.It could be seen that hyperspectral imaging technology could be used to detect for potassium sorbate in milk.Meanwhile,it also provided methodological supports for the rapid detection of other preservatives in milk.展开更多
基金This work is supported by the Key R&D Program of Zhejiang Province(No.2021C03183)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0506)the National Natural Science Foundation of China(No.2017YFC0307500).
文摘Designing a high-fidelity cutting device is one of the difficulties in hydrate samples pressure-holding transfer.Due to the limitations of the existing mechanical system,there is much damage to the cut surface of hydrate samples,with many chips produced,which seriously affects the quality of samples.In this paper,a new cutting device utilizes two servo motors to achieve a high degree of automation.Using the Archimedes spiral,it achieves low disturbance of the cut surface and provides accurate control of the process.In addition,due to the operation of the sample long-stroke push unit,cutting hydrate samples of any length with almost no chips within a short cutting time can be achieved.Laboratory and sea tests have achieved all design requirements of the equipment and strongly demonstrate its benefit and stability.It is concluded that this new high-fidelity cutting technology is practically efficient.The physical state of the hydrate can be maintained to the greatest extent,and thus the new equipment provides significant support for the exploration and development of hydrate resources.
基金Sponsored by National Natural Science Foundation of China(31460200)Natural Science Foundation of Tibet(2014-2015)
文摘Soritia leptalina endangers mainly Quercus aquifolioides, and it became particularly rampant on Q. aquifolioides in Linzhi area, Tibet. By applying field investigation and lab analysis, this study explored the spatial distribution type and sampling technology of S. leptalina larvae on Q. aquifolioides. The results showed that insect density in the upper layer of tree canopy is higher than that in the middle and lower layer,that in the upper, middle and lower layer of different levels varies greatly, and insect density in different directions follows the sequence: east > north > west > south; spatial distribution of S. leptalina on Q.aquifolioides belongs to aggregation type, larvae show mutual repulsion; aggregation of S. leptalina is the result of biological characteristics of its larvae and the habitat environment; taking Iwa regression model as the basis, the optimal sampling quantity is determined. The study disclosed the spatial distribution rules of S.leptalina on Q. aquifolioides, and on the basis of which could provide the theoretical basis for preventing Q.aquifolioides from the damage of S. leptalina, and also scientific support for studying the spatial distribution pattern of this insect and its natural enemies on other hosts.
文摘The core sampling experiments were conducted after hydraulic fracturing in the three-dimensional development zone of Fuling shale gas.Six coring wells of different well types were systematically designed.Based on the integrated engineering technology of post-fracturing drilling,coring and monitoring of shale and the analysis of fracture source tracing,the evaluation of the fracture network after fracturing in the three-dimensional development of shale gas was conducted.The data of core fractures after fracturing indicate that three major types of fractures are formed after fracturing:natural fractures,hydraulic fractures,and fractures induced by external mechanical force,which are further classified into six subcategories:natural structural fractures,natural bedding fractures,hydraulic fractures,hydraulically activated fractures,drilling induced fractures,and fractures induced by core transportation.The forms of the artificial fracture network after fracturing are complex.Hydraulic fractures and hydraulically activated fractures interweave with each other,presenting eight forms of artificial fracture networks,among which the“一”-shaped fracture is the most common,accounting for approximately 70%of the total fractures.When the distance to the fractured wellbore is less than 35 m,the density of the artificial fracture network is relatively high;when it is 35–100 m,the density is lower;and when it is beyond 100 m,the density gradually increases.The results of the fracture tracing in the core sampling area confirm that the current fracturing technology can essentially achieve the differential transformation of the reservoir in the main area of Jiaoshiba block in Fuling.The three-layer three-dimensional development model can efficiently utilize shale gas reserves,although there is still room for improvement in the complexity and propagation uniformity of fractures.It is necessary to further optimize technologies such as close-cutting combined with temporary blocking and deflection within fractures or at fracture mouths,as well as limited flow perforation techniques,to promote the balanced initiation and extension of fractures.
基金supported by the Department of Biotechnology,Ministry of Science and Technology,Government of India(No.BT/PR39032/ADV/90/285/2020).
文摘Management strategies and the use of advanced technologies are equally important for determining the sample number and sampling frame for successful field sampling for animal disease prevalence studies.The quality of the biological samples collected in the field has a direct bearing on the integrity of the data generated,prevalence estimates and subsequent policy decisions on disease control.Hence,compromising the quality of biological samples collected in the field could potentially undermine the priority setting principles in disease control strategies.Biological samples collected from domestic animals in the field are precious materials and require meticulous planning for sample collection,sample storage in the field,transportation,and storage in the laboratory.Poorly managed field sampling has a significant detrimental impact on the sample quality and quantity and directly affects the accuracy of disease prevalence data.A bad choice of sampling tools,containers,storage and transport all have a negative impact on the integrity of the sample and consequently have an impact on the outcome.Over the last two years,as part of our one health animal sampling work in ndia,we have observed challenges and opportunities in the field sampling of animals for disease prevalence studies.This paper aims to provide information on management practices and technologies for efficient biological sample collection from the field and ensure that good quality samples are available fortesting.
文摘This article reviews Mars sampling and return technology,by retrieving and analyzing the patents of domestic and foreign sampling equipment and mechanism technology,Mars surface removal technology and ultra-highspeed light and small sample return technology.It conducts patent analysis from the macro-technical view down to the micro-specific content view using statistical,quantitative and qualitative analysis methods.In the process of macro-analysis,it analyzes patent data from multiple perspectives such as time,region,technical composition,and applicants,and establishes the development trends for Mars sampling and return technology at home and abroad.In the process of micro-analysis,through the analysis and interpretation of key patents,we can learn the development priorities and development direction of foreign Mars sampling and return technology.This paper also proposes China’s Mars sampling and return technology development suggestions.
基金Natural Science Foundation of Inner Mongolia Autonomous Region of China(No.2013MS0916)Research Program of Science and Technology at Universities of Inner Mongolia Autonomous Region(No.NJZY237)
文摘With the appearance of novel radar signal with low intercept probability, the bandwidth of radar receiver is wider and wider. Wideband digital receiver becomes a research hotspot in the field of communication, radar and electronic reconnaissance, etc. As one of wideband digital receiver systems, digital channelized receiver has become a research emphasis due to the characteristics of full probability receiving and processing multiple signals. Digital channelized technology and signal sampling theory are deeply studied and an efficient channelized model is derived based on filter banks. The correctness of the model is verified by computer simulation The model has less computation compared with the traditional model, which is suitable for engineering application
基金the Special Project of Major Theoretical Research and Interpretation of Philosophy and Social Sciences of Chongqing Municipal Education Commission,China(19SKZDZX15)the Key Project of Humanities and Social Sciences Research of Chongqing Education Commission,China(18SKSJ003)the Funding for Cultivating Major Projects in Humanities and Social Sciences of Southwest University,China(SWU1809009)。
文摘This study examines the impact of farmers’cooperatives participation and technology adoption on their economic welfare in China.A double selectivity model(DSM)is applied to correct for sample selection bias stemming from both observed and unobserved factors,and a propensity score matching(PSM)method is applied to calculate the agricultural income difference with counter factual analysis using survey data from 396 farmers in 15 provinces in China.The findings indicate that farmers who join farmer cooperatives and adopt agricultural technology can increase agricultural income by 2.77 and 2.35%,respectively,compared with those non-participants and non-adopters.Interestingly,the effect on agricultural income is found to be more significant for the low-income farmers than the high-income ones,with income increasing 5.45 and 4.51%when participating in farmer cooperatives and adopting agricultural technology,respectively.Our findings highlight the positive role of farmer cooperatives and agricultural technology in promoting farmers’economic welfare.Based on the findings,government policy implications are also discussed.
文摘Objective:To present an integrated molecular biology dedicated system for tuberculosis diagnosis.Methods:One hundred and five sputum specimens from patients strongly suspected by clinical parameters of tuberculosis were studied by Ziehl-Neelsen staining,by cultivation on solid medium and by a balanced hemincsted fluorometric PCR system(Orange C3TB) that could preserve worker safety and produce a rather pure material free of potential inhibitors. DNA amplification was performed in a low cost tuberculosis termocycler-fluorotneter.Produced double stranded DNA was flurometrically detected.The whole reaction was conducted in one single tube which would not be opened after adding the processed sample in order to minimize the risk of cross contamination with amplicons.Results:The assay was able to delect 30 bacillus per sample mL with 99.8%interassay variation coefficient.PCR was positive in 23(21.9%) tested samples(21 of them were smear negative).In our study it showed a preliminary sensitivity of 94.5%for sputum and an overall specificity of 98.7%.Conclusions:Total run time of the test is 4 h with 2.5 real working time.All PCR positive samples are also positive by microbiological culture and clinical criteria.Results show that it could be a very useful tool to increase detection efficiency of tuberculosis disease in low bacilus load samples.Furthermore,its low cost and friendly using make it feasible to run in poor regions.
文摘Objective:To surveill emerging variants by nanopore technology-based genome sequencing in different COVID-19 waves in Sri Lanka and to examine the association with the sample characteristics,and vaccination status.Methods:The study analyzed 207 RNA positive swab samples received to sequence laboratory during different waves.The N gene cut-off threshold of less than 30 was considered as the major inclusion criteria.Viral RNA was extracted,and elutes were subjected to nanopore sequencing.All the sequencing data were uploaded in the publicly accessible database,GISAID.Results:The Omicron,Delta and Alpha variants accounted for 58%,22%and 4%of the variants throughout the period.Less than 1%were Kappa variant and 16%of the study samples remained unassigned.Omicron variant was circulated among all age groups and in all the provinces.Ct value and variants assigned percentage was 100%in Ct values of 10-15 while only 45%assigned Ct value over 25.Conclusions:The present study examined the emergence,prevalence,and distribution of SARS-CoV-2 variants locally and has shown that nanopore technology-based genome sequencing enables whole genome sequencing in a low resource setting country.
文摘Ultrafast optoelectronic technology has been widely used in terahertz time domain spectrum,terahertz imaging technology,terahertz communication and so on,and great progress has been achieved in the past two decade.Recently,this innovative technology has been applied in radio metrology and supplied a potential and hopeful method to solve the existent challenges of calibration devices and equipments with bandwidth up to 100 GHz.This paper generally summarizes the emerging applications of the ultrafast optoelectronic technology in radio metrology.The main applications of this technology in calibrating broadband sampling oscilloscopes,the high-speed photodiodes and calibrating the electrical pulse generators are emphasized,and the testing of monolithic microwave integrated circuits is also presented.
基金Supported by the National Key Research and Development Program of China(2016YFD0700204-02)China Agriculture Research System(CARS-36)Heilongjiang Post-doctoral Subsidy Project of China(LBH-Z17020)。
文摘To ensure the quality and safety of pure milk,detection method of typical preservative-potassium sorbate in milk was researched in this paper.Hyperspectral imaging technology was applied to realize rapid detection.Influence factors for hyperspectral data collection for milk samples were firstly researched,including height of sample,bottom color and sample filled up container or not.Pretreatment methods and variable selection algorithms were applied into original spectral data.Rapid detection models were built based on support vector machine method(SVM).Finally,standard normalized variable(SNV)-competitive adaptive reweighted sampling(CARS)and SVM model was chosen in this paper.The accuracies of calibration set and testing set were 0.97 and 0.97,respectively.Kappa coefficient of the model was 0.93.It could be seen that hyperspectral imaging technology could be used to detect for potassium sorbate in milk.Meanwhile,it also provided methodological supports for the rapid detection of other preservatives in milk.
