Premature senescence in Bacillus thuringiensis(Bt)cotton has emerged as a significant challenge to the formation and realization of fiber yield and quality since its commercialization in 1997.Initially,premature senes...Premature senescence in Bacillus thuringiensis(Bt)cotton has emerged as a significant challenge to the formation and realization of fiber yield and quality since its commercialization in 1997.Initially,premature senescence was thought to be an inherent trait associated with the Bt gene.However,subsequent research and practice have demonstrated that it is not directly linked to the Bt gene but rather results from a physiological imbalance between the sink and source,as well as between the root and shoot in Bt cotton.This short review provides an overview of the causes,mechanisms,and control measures for premature senescence in Bt cotton.It offers valuable insights for future research and the sustainable application of transgenic crops.展开更多
We review and compare two definitions of rough set approximations.One is defined by a pair of sets in the universe and the other by a pair of sets in the quotient universe.The latter definition,although less studied,i...We review and compare two definitions of rough set approximations.One is defined by a pair of sets in the universe and the other by a pair of sets in the quotient universe.The latter definition,although less studied,is semantically superior for interpreting rule induction and is closely related to granularity switching in granular computing.Numerical measures about the accuracy and quality of approximations are examined.Several semantics difficulties are commented.展开更多
Embankment stability is the primary problem for the expressway construction in permafrost regions.The proposed Qinghai-Tibet Expressway(QTE)is planned to construct along the Qinghai-Tibet Project Corridor.Confronted w...Embankment stability is the primary problem for the expressway construction in permafrost regions.The proposed Qinghai-Tibet Expressway(QTE)is planned to construct along the Qinghai-Tibet Project Corridor.Confronted with harsh environmental condition and intense heat exchange between earth and atmosphere,it is necessary to predict and evaluate the stability of the proposed QTE.In this study,the factors affecting the embankment stability are analyzed firstly.And then,a scheme for the stability evaluation of the embankment is established.Finally,the evaluation scheme is used for the pre-evaluation of the stability for the proposed QTE with different geothermal regulation measures(GRMs).The results indicate that the influencing factors include climatic environment,permafrost property,engineering condition and geological condition,and among them,engineering condition and permafrost property are the main influence factors for embankment stability.The stability of the proposed QTE varies greatly in the different geomorphological regions.The application effect and contribution to embankment stability of the existing GRMs are different,and using GRMs cannot completely overcome the influence of various factors on expressway stability.In the construction process,different GRMs should be adopted depending on the geomorphological environment where the embankment is located to ensure the embankment stability.展开更多
A lifetime prediction method for high-reliability tantalum （Ta） capacitors was proposed, based on multiple degradation measures and grey model （GM）. For analyzing performance degradation data, a two-parameter mode...A lifetime prediction method for high-reliability tantalum （Ta） capacitors was proposed, based on multiple degradation measures and grey model （GM）. For analyzing performance degradation data, a two-parameter model based on GM was developed. In order to improve the prediction accuracy of the two-parameter model, parameter selection based on particle swarm optimization （PSO） was used. Then, the new PSO-GM（1, 2, co） optimization model was constructed, which was validated experimentally by conducting an accelerated testing on the Ta capacitors. The experiments were conducted at three different stress levels of 85, 120, and 145℃. The results of two experiments were used in estimating the parameters. And the reliability of the Ta capacitors was estimated at the same stress conditions of the third experiment. The results indicate that the proposed method is valid and accurate.展开更多
The existing studies of geological relics have formed a classification system,which is based on geological relic cause factors.According to the geological relics of the tourist conception and perspective of tourism ev...The existing studies of geological relics have formed a classification system,which is based on geological relic cause factors.According to the geological relics of the tourist conception and perspective of tourism evaluation examples from Hunan Province,the author proposed the展开更多
Agile manufacturing is a new production mode. This pa per discusses the four problems of production management in the environment of a gile manufacturing, and some countermeasures are advanced: (1) Organization of pro...Agile manufacturing is a new production mode. This pa per discusses the four problems of production management in the environment of a gile manufacturing, and some countermeasures are advanced: (1) Organization of production. Traditional MTO production or MTS production ca n not meet the requirement of agile manufacturing which request both high produc tivity and the manufacturing flexibility. For this, the paper advances best way is to use the production organization mode of MCP (Mass Customization Production ),and some strategies of MCP are discussed. (2) Production planning. The requirement of agile manufacturing to production pl anning embodies in two facets: synchronization and flexibility. The paper su ggests that the structure and function of MRPII system should be improved in ord er to meet the demand of agile manufacturing. (3) Production control. The problem of production control is how to reduce the u ncertainty of hand over time between enterprises and increase the production syn chronization level. The paper advances some research direction on improving production ability. (4) Quality control. The problems of quality management are how to transfer the information of customer’s quality requirement between different organizations an d how to keep the consistency and stability of quality. Some countermeasures are advanced. In the end of the paper, one case advanced administrates how to utilize the thou ghts of agile manufacturing to upgrade the competition ability.展开更多
This paper introduces a new aggregation model by using induced and heavy aggregation operators in distances measures such as the Hamming distance.It is called the induced heavy ordered weighted averaging（OWA） dista...This paper introduces a new aggregation model by using induced and heavy aggregation operators in distances measures such as the Hamming distance.It is called the induced heavy ordered weighted averaging（OWA） distance（IHOWAD） operator.This paper studies some of its main properties and a wide range of particular cases such as the induced heavy OWA（IHOWA） operator,the induced OWA distance（IOWAD） operator and the heavy OWA distance（HOWAD） operator.This approach is generalized by using generalized and quasi-arithmetic means obtaining the induced generalized IHOWAD（IGHOWAD） operator and the Quasi-IHOWAD operator.An application of the new approach in a decision making problem regarding the selection of strategies is developed.展开更多
The present study was conducted in four districts of Punjab Province to examine the attitude of milk producers and milk collection agents toward compliance of milk quality and safety parameters. In current scenario, t...The present study was conducted in four districts of Punjab Province to examine the attitude of milk producers and milk collection agents toward compliance of milk quality and safety parameters. In current scenario, the attitude of consumers for safe food in accordance to quality standards is ever increasing. The dairy industry in Pakistan is confronting many challenges to adapt these food safety and quality measures. This study was purposely conducted in the south region of Punjab Province, as this region has rich population of livestock and milk production. To collect essential data, field study was carded out in selected four districts of Punjab Province. Field survey for dairy farmers and milk collection centers was performed in two phases. The analysis of primary data was carried out by calculating the Likert scale mean value, analysis of variance （one-way） and other descriptive statistics tools. The results showed that 76.4% milk producers had no awareness about Punjab food quality laws; as Likert-scale mean value was 1.93. The compliance level for the management practices such as Hazard Analysis of Critical Control Point （HCCAP）, Good Animal Practices （GAP） and Good Veterinary Practices （GVP） etc. was also very poor. Approximately, 32.57% milk collectors （very frequently） applied milk quality testing parameters whereas 50.72% milk collectors merely used sensory quality inspection methods at the time of milk purchase from dairy farmers. For a sustainable supply of good quality raw milk to the dairy industry in Pakistan, it was recommended that the departments for hygiene and food inspection should be vigilant. The prescribed food safety laws relating to milk production and marketing activities should be enforced properly to improve the situation.展开更多
Most of China's wetland areas are located in the Sanjiang Plain.This area has 207×10 4 hm 2 of wet and low lying farmland,of which 59% is cropped.During the 1970s and 1980s,the Chinese government organize...Most of China's wetland areas are located in the Sanjiang Plain.This area has 207×10 4 hm 2 of wet and low lying farmland,of which 59% is cropped.During the 1970s and 1980s,the Chinese government organized intensive scientific research into potential changes to existing natural resources conditions for these farmlands.The aim was to change the water resources regime to one that was beneficial to crop production.Arterial drainage,field drainage and appropriate sub soil treatments were required.The relation between plant products industry and the Four Waters distribution,also the main measures of the Four Waters converting in wet and low lying farmland were discussed in the paper.展开更多
[Background]As one of the most serious environmental issues in the world,soil erosion causes water pollution,reservoir siltation,soil productivity decline,thus threatens agricultural systems and even affects global cl...[Background]As one of the most serious environmental issues in the world,soil erosion causes water pollution,reservoir siltation,soil productivity decline,thus threatens agricultural systems and even affects global climate.The benefits of ecological soil and water conservation measures(ESWCMs,such as micro basins tillage and contour tillage)are widely understood,including runoff and soil loss reducing to a certain extent when compared with traditional tillage.While few studies have focused on China’s different soil types and erosion characteristics.[Methods]We reviewed literature from Web of Science,Scopus,and China National Knowledge Infrastructure using terms like“Conservation practice”“Contour tillage”“Runoff”“Sediment”“Erosion”and“China”and retained literatures based on criteria such as natural or simulated precipitation,runoff or soil loss data,reported replications and statistics,recorded factors like location and slope,and at least two data pairs per group.Ultimately,49 literatures were selected to quantify the impacts on different ESWCMs and identify the slope and precipitation for the greatest runoff and sediment reduction by calculating the log response ratio(LRR).[Results]The three regions’soil and water conservation benefits varied due to the differences in climate,terrain,and soil properties:1)ESWCMs applied in the black soil region of Northeast China were the most effective in reducing runoff and soil loss(66.65%runoff and 75.83%sediment),followed by those applied in the purple soil region of Southwest China(39.98%runoff and 58.30%sediment)and loess soil region of Northwest China(16.36%runoff and 32.44%sediment).2)Micro basins tillage(MBT)(71.79%runoff and 87.03%sediment)no-tillage with mulch(NTM)(17.30%runoff and 32.51%sediment),collecting soil to form a ridge with no-till(CSNT)(55.78%runoff and 71.36%sediment reduction)were the most efficient soil and water conservation measures in controlling water erosion in the black soil of Northeast China,the loess soil region of Northwest China and the purple soil region of Southwest China,respectively.3)The slope gradients ranged from 0-3°,>3°-5°and>10°-15°(0-3°:97.09%;>3°-5°:74.62%;and>10°-15°:39.41%)caused the largest reduction of runoff in the black soil region of Northeast China,the loess soil region of Northwest China,and the purple soil region of Southwest China.Meanwhile,the effects of sediment reduction were the most obvious,ranging from 0-3°,>10°-15°,and>20°-25°(0-3°:89.32%;>10°-15°:75.94%;and>20°-25°:67.25%).4)The effect of ESWCMs under rainstorms was the most obvious in the black soil region of Northeast China.The effect on runoff reduction under light rain in the purple soil region of Southwest China was the most obvious,but it failed to pass the significance test in sediment reduction.[Conclusions]The results provided optimal conservation tillage measures for three regions,different slopes and different rainfalls,and provided data support for reducing regional soil and water loss in China.展开更多
This work investigates the correlation between a large number of widely used ground motion intensity measures(IMs) and the corresponding liquefaction potential of a soil deposit during earthquake loading. In order to ...This work investigates the correlation between a large number of widely used ground motion intensity measures(IMs) and the corresponding liquefaction potential of a soil deposit during earthquake loading. In order to accomplish this purpose the seismic responses of 32 sloping liquefiable site models consisting of layered cohesionless soil were subjected to 139 earthquake ground motions. Two sets of ground motions, consisting of 80 ordinary records and 59 pulse-like near-fault records are used in the dynamic analyses. The liquefaction potential of the site is expressed in terms of the the mean pore pressure ratio, the maximum ground settlement, the maximum ground horizontal displacement and the maximum ground horizontal acceleration. For each individual accelerogram, the values of the aforementioned liquefaction potential measures are determined. Then, the correlation between the liquefaction potential measures and the IMs is evaluated. The results reveal that the velocity spectrum intensity(VSI) shows the strongest correlation with the liquefaction potential of sloping site. VSI is also proven to be a sufficient intensity measure with respect to earthquake magnitude and source-to-site distance, and has a good predictability, thus making it a prime candidate for the seismic liquefaction hazard evaluation.展开更多
Ⅰ. The present Situation of Transnational Corporations’ Investment in TEDA (1 ) General situation Since its founding ten years ago, especially since 1992. TEDA has achieved encouraging successesin undertaking major ...Ⅰ. The present Situation of Transnational Corporations’ Investment in TEDA (1 ) General situation Since its founding ten years ago, especially since 1992. TEDA has achieved encouraging successesin undertaking major projects. drawing the attention of leading consortia, omnibearingly solicitingbusiness and drawing foreign capital. By September 30, 1994, TEDA had approved 2054 solely for-展开更多
The carrying capacity of Sungo Bay for the culture of scallop Chlamys farreri was estimated by calculating the supply and demand of organic carbon produced by primary production.The carrying capacity for the large sca...The carrying capacity of Sungo Bay for the culture of scallop Chlamys farreri was estimated by calculating the supply and demand of organic carbon produced by primary production.The carrying capacity for the large scallops (5～6 cm shell height) is about 35 ind./m 2,which is 15 ind./m 2 lower than the actual cultivating density.By calculating the total supply and demand of inorganic nutrient,the carrying capacity of the bay for kelp Laminaria japanica was estimated for the first time in the world.Based on the results from assessment of carrying capacity,some optimizing measures such as polyculture of bivalves and kelp,controlling fouling organisms,adjusting the size of longline block,enlarging the navigation channel and so on were proposed and practiced in the bay.展开更多
The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts....The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.展开更多
On-machine measurement(OMM)stands out as a pivotal technology in complex curved surface adaptive machining.However,the complex structure inherent in workpieces poses a significant challenge as the stylus orientation f...On-machine measurement(OMM)stands out as a pivotal technology in complex curved surface adaptive machining.However,the complex structure inherent in workpieces poses a significant challenge as the stylus orientation frequently shifts during the measurement process.Consequently,a substantial amount of time is allocated to calibrating pre-travel error and probe movement.Furthermore,the frequent movement of machine tools also increases the influence of machine errors.To enhance both accuracy and efficiency,an optimization strategy for the OMM process is proposed.Based on the kinematic chain of the machine tools,the relationship between the angle combination of rotary axes,the stylus orientation,and the calibration position of pre-travel error is disclosed.Additionally,an OMM efficiency optimization model for complex curved surfaces is developed.This model is solved to produce the optimal efficiency angle combinations for each to-be-measured point.Within each angle combination,the effects of positioning errors on measurement results are addressed by coordinate system offset and measurement result compensation method.Finally,the experiments on an impeller are used to demonstrate the practical utility of the proposed method.展开更多
基金supported by National Key Research and Development Program of China(2024YFD2300221)China Agricultural Research System(CARS-15–15)+1 种基金Agricultural Scientific and Technological Innovation Project of Shandong Academy of Agricultural Sciences(CXGC2024D03)Dong Hezhong Studio for Popularization of Science and Technology in Salt Tolerant Industrial Crops(202228297).
文摘Premature senescence in Bacillus thuringiensis(Bt)cotton has emerged as a significant challenge to the formation and realization of fiber yield and quality since its commercialization in 1997.Initially,premature senescence was thought to be an inherent trait associated with the Bt gene.However,subsequent research and practice have demonstrated that it is not directly linked to the Bt gene but rather results from a physiological imbalance between the sink and source,as well as between the root and shoot in Bt cotton.This short review provides an overview of the causes,mechanisms,and control measures for premature senescence in Bt cotton.It offers valuable insights for future research and the sustainable application of transgenic crops.
文摘We review and compare two definitions of rough set approximations.One is defined by a pair of sets in the universe and the other by a pair of sets in the quotient universe.The latter definition,although less studied,is semantically superior for interpreting rule induction and is closely related to granularity switching in granular computing.Numerical measures about the accuracy and quality of approximations are examined.Several semantics difficulties are commented.
基金Project(2019QZKK0905)supported by the Second Tibetan Plateau Scientific Expedition and Research(STEP)Program,ChinaProject(41901074)supported by the National Natural Science Foundation of China+2 种基金Project(2020A1515010745)supported by the Natural Science Foundation of Guangdong Province,ChinaProject(SKLFSE201810)supported by the Open Fund of the State Key Laboratory of Frozen Soil Engineering,ChinaProject(2019MS119)supported by the Fundamental Research Funds for the Central Universities,China。
文摘Embankment stability is the primary problem for the expressway construction in permafrost regions.The proposed Qinghai-Tibet Expressway(QTE)is planned to construct along the Qinghai-Tibet Project Corridor.Confronted with harsh environmental condition and intense heat exchange between earth and atmosphere,it is necessary to predict and evaluate the stability of the proposed QTE.In this study,the factors affecting the embankment stability are analyzed firstly.And then,a scheme for the stability evaluation of the embankment is established.Finally,the evaluation scheme is used for the pre-evaluation of the stability for the proposed QTE with different geothermal regulation measures(GRMs).The results indicate that the influencing factors include climatic environment,permafrost property,engineering condition and geological condition,and among them,engineering condition and permafrost property are the main influence factors for embankment stability.The stability of the proposed QTE varies greatly in the different geomorphological regions.The application effect and contribution to embankment stability of the existing GRMs are different,and using GRMs cannot completely overcome the influence of various factors on expressway stability.In the construction process,different GRMs should be adopted depending on the geomorphological environment where the embankment is located to ensure the embankment stability.
基金Project(Z132012) supported by the Second Five Technology-based Fund in Science and Industry Bureau of ChinaProject(1004GK0032) supported by General Armament Department for the Common Issues of Military Electronic Components,China
文摘A lifetime prediction method for high-reliability tantalum （Ta） capacitors was proposed, based on multiple degradation measures and grey model （GM）. For analyzing performance degradation data, a two-parameter model based on GM was developed. In order to improve the prediction accuracy of the two-parameter model, parameter selection based on particle swarm optimization （PSO） was used. Then, the new PSO-GM（1, 2, co） optimization model was constructed, which was validated experimentally by conducting an accelerated testing on the Ta capacitors. The experiments were conducted at three different stress levels of 85, 120, and 145℃. The results of two experiments were used in estimating the parameters. And the reliability of the Ta capacitors was estimated at the same stress conditions of the third experiment. The results indicate that the proposed method is valid and accurate.
文摘The existing studies of geological relics have formed a classification system,which is based on geological relic cause factors.According to the geological relics of the tourist conception and perspective of tourism evaluation examples from Hunan Province,the author proposed the
文摘Agile manufacturing is a new production mode. This pa per discusses the four problems of production management in the environment of a gile manufacturing, and some countermeasures are advanced: (1) Organization of production. Traditional MTO production or MTS production ca n not meet the requirement of agile manufacturing which request both high produc tivity and the manufacturing flexibility. For this, the paper advances best way is to use the production organization mode of MCP (Mass Customization Production ),and some strategies of MCP are discussed. (2) Production planning. The requirement of agile manufacturing to production pl anning embodies in two facets: synchronization and flexibility. The paper su ggests that the structure and function of MRPII system should be improved in ord er to meet the demand of agile manufacturing. (3) Production control. The problem of production control is how to reduce the u ncertainty of hand over time between enterprises and increase the production syn chronization level. The paper advances some research direction on improving production ability. (4) Quality control. The problems of quality management are how to transfer the information of customer’s quality requirement between different organizations an d how to keep the consistency and stability of quality. Some countermeasures are advanced. In the end of the paper, one case advanced administrates how to utilize the thou ghts of agile manufacturing to upgrade the competition ability.
基金supported by the projects JC2009-00189 and A/023879/09 from the Spanish Ministry of Science and Innovation
文摘This paper introduces a new aggregation model by using induced and heavy aggregation operators in distances measures such as the Hamming distance.It is called the induced heavy ordered weighted averaging（OWA） distance（IHOWAD） operator.This paper studies some of its main properties and a wide range of particular cases such as the induced heavy OWA（IHOWA） operator,the induced OWA distance（IOWAD） operator and the heavy OWA distance（HOWAD） operator.This approach is generalized by using generalized and quasi-arithmetic means obtaining the induced generalized IHOWAD（IGHOWAD） operator and the Quasi-IHOWAD operator.An application of the new approach in a decision making problem regarding the selection of strategies is developed.
基金Supported by the National Natural Science Foundation of China(7167031183)Impact of Infant Powder Milk Safety Trust Index on Product Competitiveness-Index Measurement,Construction of Related Market Model and Market Simulation(G0300502)
文摘The present study was conducted in four districts of Punjab Province to examine the attitude of milk producers and milk collection agents toward compliance of milk quality and safety parameters. In current scenario, the attitude of consumers for safe food in accordance to quality standards is ever increasing. The dairy industry in Pakistan is confronting many challenges to adapt these food safety and quality measures. This study was purposely conducted in the south region of Punjab Province, as this region has rich population of livestock and milk production. To collect essential data, field study was carded out in selected four districts of Punjab Province. Field survey for dairy farmers and milk collection centers was performed in two phases. The analysis of primary data was carried out by calculating the Likert scale mean value, analysis of variance （one-way） and other descriptive statistics tools. The results showed that 76.4% milk producers had no awareness about Punjab food quality laws; as Likert-scale mean value was 1.93. The compliance level for the management practices such as Hazard Analysis of Critical Control Point （HCCAP）, Good Animal Practices （GAP） and Good Veterinary Practices （GVP） etc. was also very poor. Approximately, 32.57% milk collectors （very frequently） applied milk quality testing parameters whereas 50.72% milk collectors merely used sensory quality inspection methods at the time of milk purchase from dairy farmers. For a sustainable supply of good quality raw milk to the dairy industry in Pakistan, it was recommended that the departments for hygiene and food inspection should be vigilant. The prescribed food safety laws relating to milk production and marketing activities should be enforced properly to improve the situation.
文摘Most of China's wetland areas are located in the Sanjiang Plain.This area has 207×10 4 hm 2 of wet and low lying farmland,of which 59% is cropped.During the 1970s and 1980s,the Chinese government organized intensive scientific research into potential changes to existing natural resources conditions for these farmlands.The aim was to change the water resources regime to one that was beneficial to crop production.Arterial drainage,field drainage and appropriate sub soil treatments were required.The relation between plant products industry and the Four Waters distribution,also the main measures of the Four Waters converting in wet and low lying farmland were discussed in the paper.
基金Science and Technology Major Project of Tibetan Autonomous Region of China(XZ202201ZD0005G02)National Natural Science Foundation of China(42277353)Chengdu Science and Technology Project(2022-YF05-01162-SN)。
文摘[Background]As one of the most serious environmental issues in the world,soil erosion causes water pollution,reservoir siltation,soil productivity decline,thus threatens agricultural systems and even affects global climate.The benefits of ecological soil and water conservation measures(ESWCMs,such as micro basins tillage and contour tillage)are widely understood,including runoff and soil loss reducing to a certain extent when compared with traditional tillage.While few studies have focused on China’s different soil types and erosion characteristics.[Methods]We reviewed literature from Web of Science,Scopus,and China National Knowledge Infrastructure using terms like“Conservation practice”“Contour tillage”“Runoff”“Sediment”“Erosion”and“China”and retained literatures based on criteria such as natural or simulated precipitation,runoff or soil loss data,reported replications and statistics,recorded factors like location and slope,and at least two data pairs per group.Ultimately,49 literatures were selected to quantify the impacts on different ESWCMs and identify the slope and precipitation for the greatest runoff and sediment reduction by calculating the log response ratio(LRR).[Results]The three regions’soil and water conservation benefits varied due to the differences in climate,terrain,and soil properties:1)ESWCMs applied in the black soil region of Northeast China were the most effective in reducing runoff and soil loss(66.65%runoff and 75.83%sediment),followed by those applied in the purple soil region of Southwest China(39.98%runoff and 58.30%sediment)and loess soil region of Northwest China(16.36%runoff and 32.44%sediment).2)Micro basins tillage(MBT)(71.79%runoff and 87.03%sediment)no-tillage with mulch(NTM)(17.30%runoff and 32.51%sediment),collecting soil to form a ridge with no-till(CSNT)(55.78%runoff and 71.36%sediment reduction)were the most efficient soil and water conservation measures in controlling water erosion in the black soil of Northeast China,the loess soil region of Northwest China and the purple soil region of Southwest China,respectively.3)The slope gradients ranged from 0-3°,>3°-5°and>10°-15°(0-3°:97.09%;>3°-5°:74.62%;and>10°-15°:39.41%)caused the largest reduction of runoff in the black soil region of Northeast China,the loess soil region of Northwest China,and the purple soil region of Southwest China.Meanwhile,the effects of sediment reduction were the most obvious,ranging from 0-3°,>10°-15°,and>20°-25°(0-3°:89.32%;>10°-15°:75.94%;and>20°-25°:67.25%).4)The effect of ESWCMs under rainstorms was the most obvious in the black soil region of Northeast China.The effect on runoff reduction under light rain in the purple soil region of Southwest China was the most obvious,but it failed to pass the significance test in sediment reduction.[Conclusions]The results provided optimal conservation tillage measures for three regions,different slopes and different rainfalls,and provided data support for reducing regional soil and water loss in China.
基金Project(5141001028)supported by International Cooperation and Exchanges of NSFC,ChinaProjects(51308566,51308565,51409025)supported by the National Natural Science Foundation of ChinaProject(CDJZR12200002)supported by the Fundamental Research Funds for the Central Universities,China
文摘This work investigates the correlation between a large number of widely used ground motion intensity measures(IMs) and the corresponding liquefaction potential of a soil deposit during earthquake loading. In order to accomplish this purpose the seismic responses of 32 sloping liquefiable site models consisting of layered cohesionless soil were subjected to 139 earthquake ground motions. Two sets of ground motions, consisting of 80 ordinary records and 59 pulse-like near-fault records are used in the dynamic analyses. The liquefaction potential of the site is expressed in terms of the the mean pore pressure ratio, the maximum ground settlement, the maximum ground horizontal displacement and the maximum ground horizontal acceleration. For each individual accelerogram, the values of the aforementioned liquefaction potential measures are determined. Then, the correlation between the liquefaction potential measures and the IMs is evaluated. The results reveal that the velocity spectrum intensity(VSI) shows the strongest correlation with the liquefaction potential of sloping site. VSI is also proven to be a sufficient intensity measure with respect to earthquake magnitude and source-to-site distance, and has a good predictability, thus making it a prime candidate for the seismic liquefaction hazard evaluation.
文摘Ⅰ. The present Situation of Transnational Corporations’ Investment in TEDA (1 ) General situation Since its founding ten years ago, especially since 1992. TEDA has achieved encouraging successesin undertaking major projects. drawing the attention of leading consortia, omnibearingly solicitingbusiness and drawing foreign capital. By September 30, 1994, TEDA had approved 2054 solely for-
文摘The carrying capacity of Sungo Bay for the culture of scallop Chlamys farreri was estimated by calculating the supply and demand of organic carbon produced by primary production.The carrying capacity for the large scallops (5～6 cm shell height) is about 35 ind./m 2,which is 15 ind./m 2 lower than the actual cultivating density.By calculating the total supply and demand of inorganic nutrient,the carrying capacity of the bay for kelp Laminaria japanica was estimated for the first time in the world.Based on the results from assessment of carrying capacity,some optimizing measures such as polyculture of bivalves and kelp,controlling fouling organisms,adjusting the size of longline block,enlarging the navigation channel and so on were proposed and practiced in the bay.
文摘The concept of emissivity has been with the scientific and engineering world since Planck formulated his blackbody radiation law more than a century ago.Nevertheless,emissivity is an elusive concept even for ex⁃perts.It is a vague and fuzzy concept for the wider community of engineers.The importance of remote sensing of temperature by measuring IR radiation has been recognized in a wide range of industrial,medical,and environ⁃mental uses.One of the major sources of errors in IR radiometry is the emissivity of the surface being measured.In real experiments,emissivity may be influenced by many factors:surface texture,spectral properties,oxida⁃tion,and aging of surfaces.While commercial blackbodies are prevalent,the much-needed grey bodies with a known emissivity,are unavailable.This study describes how to achieve a calibrated and stable emissivity with a blackbody,a perforated screen,and a reliable and linear novel IR thermal sensor,18 dubbed TMOS.The Digital TMOS is now a low-cost commercial product,it requires low power,and it has a small form factor.The method⁃ology is based on two-color measurements,with two different optical filters,with selected wavelengths conform⁃ing to the grey body definition of the use case under study.With a photochemically etched perforated screen,the effective emissivity of the screen is simply the hole density area of the surface area that emits according to the blackbody temperature radiation.The concept is illustrated with ray tracing simulations,which demonstrate the approach.Measured results are reported.
基金Projects(51775445,52175435)supported by the National Natural Science Foundation of ChinaProject(CX2023051)supported by the Innovation Foundation for Doctor Dissertation of Northwestern Polytechnical University,China。
文摘On-machine measurement(OMM)stands out as a pivotal technology in complex curved surface adaptive machining.However,the complex structure inherent in workpieces poses a significant challenge as the stylus orientation frequently shifts during the measurement process.Consequently,a substantial amount of time is allocated to calibrating pre-travel error and probe movement.Furthermore,the frequent movement of machine tools also increases the influence of machine errors.To enhance both accuracy and efficiency,an optimization strategy for the OMM process is proposed.Based on the kinematic chain of the machine tools,the relationship between the angle combination of rotary axes,the stylus orientation,and the calibration position of pre-travel error is disclosed.Additionally,an OMM efficiency optimization model for complex curved surfaces is developed.This model is solved to produce the optimal efficiency angle combinations for each to-be-measured point.Within each angle combination,the effects of positioning errors on measurement results are addressed by coordinate system offset and measurement result compensation method.Finally,the experiments on an impeller are used to demonstrate the practical utility of the proposed method.
