[Objective] The paper is to construct the logistics tracking management system of tropical agricultural products based on supply chain.[Method] With tropical agricultural products in Hainan as study object,based on lo...[Objective] The paper is to construct the logistics tracking management system of tropical agricultural products based on supply chain.[Method] With tropical agricultural products in Hainan as study object,based on logistics supply chain files and electronic tag coding of agricultural products,cold chain temperature and humidity monitoring,vehicle transportation positioning,data exchange of XML Web services and role-based permission dynamic allocation,the multi-level multi-permission and multi-role logistics tracking management system of tropical agricultural products has been established.[Result] The system constructs information exchange platform for various links of logistics supply chain of tropical agricultural products,which realizes the entire quality monitoring and information tracing of agricultural products,thus enhancing the competitiveness of supply chain in company.[Conclusion] The system has good application and extension prospect.展开更多
A three-dimensional laser absorption model based on ray tracing was established to describe the coupled interaction of a laser beam with particles in the powder layers of pure tungsten(W)material processed by selectiv...A three-dimensional laser absorption model based on ray tracing was established to describe the coupled interaction of a laser beam with particles in the powder layers of pure tungsten(W)material processed by selective laser melting(SLM).The influence of particle size on the powder-to-laser absorptivity and underlying absorption behavior was investigated.An intrinsic relationship between the absorption,distribution of absorbed irradiance within the powder layers,and surface morphology and geometric characteristics(e.g.,contact angle,width and height of tracks,and remelted depth)of the laser scanning tracks is presented here.Simulation conclusions indicate that the absorptivity of the powder layers considerably exceeds the single powder particle value or the dense solid material value.With an increase in particle size,the powder layer absorbs less laser energy.The maximum absorptivity of theWpowder layers reached 0.6030 at the particle size of 5 lm.The distribution of laser irradiance on the particle surface was sensitive to particle size,azimuthal angle,and the position of the powder particles on the substrate.The maximum irradiance in the powder layers decreased from 1.117×10^–3 to 0.85×10^–3W·μm^-2 and the contour of the irradiance distribution in the center of the irradiated area gradually contracted when the particle size increased from 5 to 45 lm.An experimental study on the surface morphologies and cross-sectional geometric characteristics of SLM-fabricated W material was performed,and the experimental results validated the mechanisms of the powder-to-laser-absorption behavior that were obtained in simulations.This work provides a scientific basis for the application of the ray-tracing model to predict the wetting and spreading ability of melted tracks during SLM additive manufacturing in order to yield a sound laser processability.展开更多
【目的】为了适应中国牧场的移动通信环境,加强动物从饲养至屠宰的全程监管,实现对动物的追踪和溯源。【方法】组合"Alien H3"和"Mifare One S70"两种特性不同的芯片,制作一种复合型的RFID动物耳标。其中"H3&q...【目的】为了适应中国牧场的移动通信环境,加强动物从饲养至屠宰的全程监管,实现对动物的追踪和溯源。【方法】组合"Alien H3"和"Mifare One S70"两种特性不同的芯片,制作一种复合型的RFID动物耳标。其中"H3"芯片适宜远距离身份识别,需要应用抗碰撞数学模型实现识别概率的优化。"S70"芯片适宜存储动物饲养日志,为了避免日志被篡改,需要采用"位运算"方式计算适宜的权限控制码。【结果】复合型耳标支持在运动中远距离识别动物身份,算法优化后,单时隙识别概率从0.055 4提升至0.379 8,表现为识别效率提高7倍;耳标还支持近距离扫描更新饲养日志,控制码设置为"70FF0869",保护日志不被篡改的同时实现透明阅读。【结论】复合型耳标可以帮助牧场追踪动物的饲养过程,避免动物在活动中错漏重要的防疫流程,并加强了动物档案的管理;复合型耳标又能支持流通环节的NFC扫描,客户可以通过手机透明地阅读动物饲养日志,实现溯源。展开更多
农产品追溯系统是解决食品安全问题的重要手段,目前常见的追溯系统往往具有适用品种单一、精度不高、可应用性弱等特点,无法满足大规模推广应用的需要。该文以建立适用面广、性能高效的农产品追溯系统为目标,分析了常见追溯系统的软件...农产品追溯系统是解决食品安全问题的重要手段,目前常见的追溯系统往往具有适用品种单一、精度不高、可应用性弱等特点,无法满足大规模推广应用的需要。该文以建立适用面广、性能高效的农产品追溯系统为目标,分析了常见追溯系统的软件框架与追溯信息数据结构,重点研究可支撑多品种追溯的动态扩展数据模型优化技术,同时以提升追溯精度、降低追溯成本为目标研究了基于位置服务(location based service,LBS)的追溯精度提升技术。针对追溯系统适用范围窄的问题,分析了追溯信息指标模型的数据结构特征,对比了常见的4种动态扩展数据模型,采用EAV与XML数据模型相结合的方法,通过可视化操作界面实现了不同品种追溯信息的动态扩展,通过性能分析发现该模型较其他两种模型时间缩短65%,查询效率提升了175%;针对追溯信息中的产地环境信息,分析了各类环境数据的可用来源和数据特征,制订了数据匹配的最小空间单元和实现方法,运用LBS技术实现了产地环境信息的自动获取,通过追溯系统之间的精度对比发现,该技术显著提高了追溯系统的宽度、深度、精确度,从而整体提升了系统追溯精度并降低了数据采集成本。该系统已在青海省应用,结果表明该系统较其他系统在适用范围、系统性能、追溯精度与追溯成本上具有明显优势。展开更多
文摘[Objective] The paper is to construct the logistics tracking management system of tropical agricultural products based on supply chain.[Method] With tropical agricultural products in Hainan as study object,based on logistics supply chain files and electronic tag coding of agricultural products,cold chain temperature and humidity monitoring,vehicle transportation positioning,data exchange of XML Web services and role-based permission dynamic allocation,the multi-level multi-permission and multi-role logistics tracking management system of tropical agricultural products has been established.[Result] The system constructs information exchange platform for various links of logistics supply chain of tropical agricultural products,which realizes the entire quality monitoring and information tracing of agricultural products,thus enhancing the competitiveness of supply chain in company.[Conclusion] The system has good application and extension prospect.
文摘A three-dimensional laser absorption model based on ray tracing was established to describe the coupled interaction of a laser beam with particles in the powder layers of pure tungsten(W)material processed by selective laser melting(SLM).The influence of particle size on the powder-to-laser absorptivity and underlying absorption behavior was investigated.An intrinsic relationship between the absorption,distribution of absorbed irradiance within the powder layers,and surface morphology and geometric characteristics(e.g.,contact angle,width and height of tracks,and remelted depth)of the laser scanning tracks is presented here.Simulation conclusions indicate that the absorptivity of the powder layers considerably exceeds the single powder particle value or the dense solid material value.With an increase in particle size,the powder layer absorbs less laser energy.The maximum absorptivity of theWpowder layers reached 0.6030 at the particle size of 5 lm.The distribution of laser irradiance on the particle surface was sensitive to particle size,azimuthal angle,and the position of the powder particles on the substrate.The maximum irradiance in the powder layers decreased from 1.117×10^–3 to 0.85×10^–3W·μm^-2 and the contour of the irradiance distribution in the center of the irradiated area gradually contracted when the particle size increased from 5 to 45 lm.An experimental study on the surface morphologies and cross-sectional geometric characteristics of SLM-fabricated W material was performed,and the experimental results validated the mechanisms of the powder-to-laser-absorption behavior that were obtained in simulations.This work provides a scientific basis for the application of the ray-tracing model to predict the wetting and spreading ability of melted tracks during SLM additive manufacturing in order to yield a sound laser processability.
文摘农产品追溯系统是解决食品安全问题的重要手段,目前常见的追溯系统往往具有适用品种单一、精度不高、可应用性弱等特点,无法满足大规模推广应用的需要。该文以建立适用面广、性能高效的农产品追溯系统为目标,分析了常见追溯系统的软件框架与追溯信息数据结构,重点研究可支撑多品种追溯的动态扩展数据模型优化技术,同时以提升追溯精度、降低追溯成本为目标研究了基于位置服务(location based service,LBS)的追溯精度提升技术。针对追溯系统适用范围窄的问题,分析了追溯信息指标模型的数据结构特征,对比了常见的4种动态扩展数据模型,采用EAV与XML数据模型相结合的方法,通过可视化操作界面实现了不同品种追溯信息的动态扩展,通过性能分析发现该模型较其他两种模型时间缩短65%,查询效率提升了175%;针对追溯信息中的产地环境信息,分析了各类环境数据的可用来源和数据特征,制订了数据匹配的最小空间单元和实现方法,运用LBS技术实现了产地环境信息的自动获取,通过追溯系统之间的精度对比发现,该技术显著提高了追溯系统的宽度、深度、精确度,从而整体提升了系统追溯精度并降低了数据采集成本。该系统已在青海省应用,结果表明该系统较其他系统在适用范围、系统性能、追溯精度与追溯成本上具有明显优势。
