Food safety management and regulation:International experiences and lessons for China

China is experiencing rapid urbanization,changes in diets,and modernization of food retailing and production. In this context,food safety can become a greater concern for a variety of reasons. The purpose of this article is to review the international experiences and lessons regarding food safety management,regulation,and consumer behavior,with the goal of identifying how to improve food safety in middle income countries such as China. International experience in addressing food safety provides two general kinds of lessons. First,a middle-income country such as China needs to develop the capacity to carry out risk analysis in order to better focus public resources on the most important risks. Second,it will be important to leverage market incentives so as to make the best use of limited public capacity to enforce standards. International experiences show that food safety management is feasible where market incentives exist,and that public-private partnerships can support the process of improving food safety management. Market incentives require effective consumer or buyer demand,mechanisms to identify and reward quality,and supply chain coordination. Public efforts can be targeted to supporting these market developments for the risks that are the greatest burden to public health.     

管道内检测器皮碗过盈量对其力学行为的影响

为了研究管道内检测器皮碗过盈量对皮碗力学行为的影响,以直径为800 mm的管道的内检测器皮碗为研究对象,分析聚氨酯材料的力学特性,建立用于分析管道内检测器皮碗过盈量的二维轴对称有限元模型。通过计算分析,得到了皮碗过盈量为0~10%时,唇缘接触应力、唇缘接触长度、夹持端角度、唇缘角度、皮碗折点内外侧应力的变化趋势,并拟合得到了过盈量与上述参数之间的关系。结果表明:随着皮碗过盈量增加,皮碗唇缘应力趋势由指数下降趋势逐渐转化为线性下降趋势;皮碗唇缘接触长度、夹持端角度的增长速率随皮碗过盈量增大而快速增加;折点内外侧应力增长速率均随皮碗过盈量增大而减小;皮碗唇缘角度随着皮碗过盈量增大而线性减小。     

非线性动力特性的仿真分析

研究非线性动力特性可视化计算的仿真问题，建立了以时域微分方程描述的数学模型，探讨了该系统运动轨迹及其演变规律的可视化表示方式。     

古汉语修辞格式及艺术分析

借代、用典、比喻、委婉、双关、互文、分承、省略是古汉语中最常见的修辞方法,学习和掌握这些修辞方法,研究其规律,对我们阅读古文,传承中华文化大有裨益。     

《黑龙江八一农垦大学学报》的社会地位及影响力分析

采取文献计量法,对黑龙江八一农垦大学学报近年的引证数据进行了统计分析,明晰了黑龙江八一农垦大学学报的进展情况及在同类期刊中所处的地位。在此基础上,提出了学报未来的发展方向和具体举措。     

物料在锤片式粉碎机中的运动分析

本文论述了镜片式粉碎机中物料的运动规律。通过物料的运动分析求出物料的运动参数与物料在粉碎室内移动的关系，从理论上解释了锤式粉碎机生产率偏低、功耗大的毛病，从而为正确使用粉碎机、正确设计锤式粉碎机提供了理论根据。     

欧亚地区植被变化特征分析

利用1982—2002年的LAI资料,采用EOF、最小二乘法等方法,研究了欧亚中高纬地区春、夏季植被的变化情况。分析结果表明,近20年来,欧亚地区春季植被变化最显著的地区在东欧平原和西西伯利亚平原;欧亚地区春季植被异常有"全区一致型"、"东西两端与中间差异型"和"东西差异型"3种模态;欧亚地区夏季植被异常有"全区一致型"、"东西两端与中间差异型"两种模态;总体来看,近20年欧亚地区植被呈现增多的趋势。     

高层建筑结构分析模型

针对高层建筑结构体系的问题，提出了相应的分析模型和分析方法，为结构分析软件提出了新的要求。     

半干旱地区杨树新品种选育初报

通过青杨派的种间杂交,在半干旱地区的杨树新品种选育中,初选出四龄树的金科5号优良无性系。对金科5号在耐干旱、耐盐碱、速生等方面的特性进行了试验研究,发现其表现优良,适于在兰干旱地区推广。     

Measurement of the Motion of Fertilizer Particles Leaving a Centrifugal Spreader Using a Fast Imaging System

Although mechanically simple, centrifugal spreaders used for mineral fertilization involve complex physics that cannot be fully characterized at the present time. We are developing sensors to evaluate the spatial distribution of the fertilizer on the ground based on the measurement of initial flight conditions of fertilizer granules after their ejection by the spreading disk. The techniques developed are based on the analysis of images of the area around the disk showing the granule ejection. A high resolution – low cost imaging system for the analysis of high speed particle projection developed for this specific purpose is presented in this paper. The system, based on a camera and a sequence of flashes, is used to characterize the centrifugal spreading of fertilizer particles ejected at speeds of approximately 30ms^–1. It automatically computes the direction of ejection and velocity of each granule observed in the image. Multi-exposure images collected with the camera installed perpendicular to the output flow of granules are analyzed to estimate the trajectories of the fertilizer granules, using different motion estimation methods.