山地电力架空线路运维质量的智能评估

山地电力架空线路大多沿山架设,穿越树竹林,周边的树竹生长缺陷引发短路故障频繁发生,造成用电客户的大量投诉,用户体验满意度下降,抢修抢险费用大幅度攀升,严重影响供电公司的信誉和售电收益.为了提升用电客户的满意度和供电公司的售电受益,采用主成分分析方法提取了山地电力架空线路通道运维质量的3个主要影响因素,它们分别是树竹生长缺陷数、缺陷的消除数和通道运维资金使用合理度.对树竹的生长规律建立一个预测模型,从而得到树竹生长缺陷数的一个预测,根据预测结果划拨架空线路所在供电所的运维资金,消除树竹生长的缺陷数,再用Logistic回归模型,构建架空线路通道运维质量智能评估模型,使供电公司对架空线路运维实现基于数据决策的模式,尽可能保证供电线路零故障运行.     

基于抗体筛查的美国猪群流行性腹泻病毒真流行率分布推断

养殖家畜的冠状病毒，如猪流行性腹泻病毒（porcine epidemic diarrhea virus，PEDV），其基因序列与蝙蝠体内冠状病毒基因序列高度相似，可引起猪肠道感染并导致仔猪大量死亡，对动物健康危害极大。本研究基于对美国猪群PEDV流行毒株表观流行率的数据挖掘作为先验信息，以2019年美国生猪入境中国西南陆路口岸的实验室抗体筛查为知识更新，利用贝叶斯统计推断方法，估计美国猪群PEDV发生的真流行率分布。结果显示，PEDV在美国猪群中的真流行率分布中位值（median）为0.005 22（95% CI=0.000 424~0.022 5），95%的高置信上限（upper confident limit，UCL）的流行率分布为3%。后验分布流行率高度右偏的概率密度统计特性推断美国猪群PEDV真流行率最大可能分布主要集中在2.5%百分位数（P_2.5%=0.000 2）与中位数（P_50%=0.005 22）之间，但不同生猪畜群间PEDV真流行率分布值可能会存在有小概率溢出分布大于0.03（P≤2.5%）的可能。此外，在现阶段口岸筛查的试剂选择方面，建议口岸首先使用基于N蛋白的ELISA抗体作为初筛，然后以基于S1重组蛋白ELISA抗体筛查作为复筛，来提高口岸对来自美国生猪的α-冠状病毒入境我国的风险认知、管控和鉴别能力。以先验分布和口岸实验室检测结果优化为基础的贝叶斯统计推断监测技术，可以为在现有知识和认知基础上最大程度阻断来自异域病原微生物入侵提供基于科学证据的风险决策技术支持，对口岸检验检疫、抽样监测和风险决策具有突破性的意义。     

气候变化适应及其影响因素研究——山东胶州湾地区居民的实证分析

为探索气候变化感知在适应决策过程中的作用机理，本研究以深度访谈数据为基础，基于“感知－适应”分析框架，采用二元Probit模型和泊松回归模型，分析胶州湾地区居民气候变化适应决策和适应选择的影响因素。研究表明，胶州湾地区绝大多数居民已经感知到气候变化，半数以上居民采取了一定的适应措施，大多数居民对适应措施效果的感到满意。居民采取适应措施介于0-4项，平均为1.07项，适应措施的普及率和多样化仍有提升空间。影响胶州湾地区居民气候变化适应决策与适应选择的主要因素存在一定差异性，但“居民对气候变化的感知”不论是对适应决策还是对适应选择的影响都较大，其中又以“对降水变化的感知”和“对气象灾害损失的感知”最为显著。     

Prematurity and Dysmaturity Are Associated With Reduced Height and Shorter Distal Limb Length in Horses

The long-term effects of gestational immaturity in the premature (defined as < 320 days gestation) and dysmature (normal term but showing some signs of prematurity) foal have not been thoroughly investigated. Studies have reported that a high percentage of gestationally immature foals with related orthopedic issues such as incomplete ossification may fail to fulfill their intended athletic purpose, particularly in Thoroughbred racing. In humans, premature birth is associated with shorter stature at maturity and variations in anatomical ratios, linked to alterations in metabolism and timing of physeal closure in the long bones. We hypothesized that gestational immaturity in horses might similarly be associated with reduced height and different anatomical ratios at maturity. In this preliminary study, the skeletal ratios of horses with a history of gestational immaturity, identified through veterinary and breeder records, were compared with those of unaffected, closely related horses (i.e., sire, dam, sibling). External measurements were taken from conformation photographs of cases (n = 19) and related horses (n = 28), and these were then combined into indices to evaluate and compare metric properties of conformation. A principal component analysis showed that the first two principal components account for 43.8% of the total conformational variation of the horses’ external features, separating horses with a rectangular conformation (body length > height at the withers), from those that are more square (body length = height at the withers). Varimax rotation of PC1 and analysis of different gestational groups showed a significant effect of gestational immaturity (P = .001), with the premature group being more affected than the dysmature group (P = .009, P = .012). Mean values for the four dominant indices showed that these groups have significantly lower distal limb to body length relationships than controls. The observed differences suggest that gestational immaturity may affect anatomical ratios at maturity, which, in combination with orthopedic issues arising from incomplete ossification, may have a further impact on long-term athletic potential.     

Mitigating nitrous oxide emissions from agricultural soils by precision management

Nitrous oxide (N₂O) emissions make up a significant part of agricultural greenhouse gas emissions. There is an urgent need to identify new approaches to the mitigation of these emissions with emerging technology. In this short review four approaches to precision managements of agricultural systems are described based on examples of work being undertaken in the UK and New Zealand. They offer the opportunity for N₂O mitigation without any reduction in productivity. These approaches depend upon new sensor technology, modeling and spatial information with which to make management decisions and interventions that can both improve agricultural productivity and environmental protection.     

基于动态规划的电动拖拉机动力电源能量控制策略研究

针对纯电动拖拉机能量利用率低、续航里程不足的问题，提出了基于超级电容和蓄电池复合的纯电动拖拉机动力电源系统。通过分析纯电动拖拉机的作业工况特点以及功率需求，对动力电源系统进行了拓扑结构选型和参数匹配，并以动力电源能耗最低为优化目标，应用动态规划对纯电动拖拉机的动力电源系统进行能量控制策略优化，对动态规划结果以及工况特点进行分析，总结出基于规则的动力电源能量控制策略，利用Matlab/Simulink建模对控制策略进行仿真。结果表明基于动态规划的控制策略能量消耗比基于规则的控制策略能量消耗减少了18%，证明了基于动态规划的能量控制策略在节能降耗方面的有效性。     

Reducing crude protein variability and maximizing savings when formulating corn-soybean meal-based feeds

Crude protein in corn and soybean meal have been documented to vary, and such inherent variability can result in under- or over-feeding of CP when feeds are formulated, leading to reduced bird growth, added input costs, and increased environmental pollution. The purpose of this study was to compare 2 grain-handling techniques and 2 feed formulation methods (linear vs. stochastic programming) to reduce CP variability in finished feeds and determine resulting costs or savings. The 2 grain-handling techniques were placing all the random batches of each delivered ingredient in to (1) a single bin (1-bin method) or (2) segregating above- and below-average samples into 2 bins (2-bin method). A fast way of estimating the composition of the ingredients is now available (near-infrared reflectance spectroscopy). Microsoft Excel workbooks were constructed to solve broiler starter feed formulation problems. Formulating feeds by linear and stochastic models based on the 2-bin method reduced CP variability by at least 50% compared with the 1-bin method. Formula cost was reduced by ˜20 cents per ton (averages of August 2012 United States ingredient prices) when the 2-bin method was used with the linear model. Formulating feed with a margin of safety increased formula cost by $3.40 per ton. Stochastic feed formulation increased formula cost to meet the specified CP level in feed at any probability of success, and formula cost was reduced substantially with the 2-bin method (up to $6.47 per ton). The magnitude of savings and reduced feed variability suggested that, regardless of the costs associated with building extra bins, the 2-bin method can be economically efficient in the long run. Therefore, it could be possible to split the batches of feed ingredients at a feed mill into above- or below-average bins before feed formulation to reduce CP variability and to maximize savings.     

开封市公共气象服务发展探讨

公共气象服务是为政府决策、民生发展提供的一项基础性公共事业。该文通过阐述开封市公共气象服务发展的现状,对比国内气象服务工作,分析其中存在的问题,以充分发挥气象服务的社会效益、经济效益。     

多线左旋螺纹的数控车削方法

文章以沈阳数控机床HT1625 FANUC 0I-TC系统为例,通过选用设置合理的切削参数和工艺,探讨多线左旋螺纹的数控车削加工。