继电保护用电流互感器的暂态特性数字仿真及电磁优化设计

本文在分析CT的暂态特性及其动态磁化过程的基础上,建立了计及铁芯饱和、局部磁滞回环、动态剩磁影响的CT单、复励磁暂态过程数字仿真模型,提出了继电保护用P、TPX、TPY、TPz级CT的电磁优化设计方法,编制了计算机程序,用于CT的电磁优化设计及数字仿真分析.     

一类挖坑机械钻头横向振动系统的最优控制问题

建立了一类挖坑机械钻头横向振动系统的数学模型,并以阻尼函数作为控制变量,研究了该系统的最优控制问题,得出了两个定理。     

Optimal cultivar mixtures in focal plant diseases

This paper deals with a study on the effects of mixtures of partially resistant cultivars in focus forming plant diseases. The focus expansion velocity in a mixture of two partially resistant cultivars depends on four parameters, the focus expansion velocity in a crop of cultivar 1 only and in a crop of cultivar 2 only, the net-reproduction in a crop of cultivar 1 and of cultivar 2, respectively. An explicit equation is developed for the damage of a cultivar mixture where the crop is infected by two physiological races of the pathogen. It is shown that cultivar mixtures exist where damage is smaller than in crops of either of the two cultivars only. A simple explicit formula is given on the basis of which it can be decided whether an optimal mixture exists for a given pathosystem.     

陕甘宁老区建立生态特区的必要性分析

本文从历史与现状方面分析了陕甘宁老区加强生态环境建设的必要性。阐述了陕甘宁老区历史上范围的变化及其对中国革命和经济建设的贡献。从多方面分析了它的自然条件 ,揭示了其自然环境的脆弱性。说明了该区经济建设取得的成就和存在的问题 ,揭示了其贫困落后的社会经济状况。提出了在该区建立生态特区以促进其生态环境建设的观点。     

土壤湿度对三氮苯类除草剂药效的影响及优化方案

以稗草为生物测定材料,运用二次正交旋转组合设计,以土壤湿度和除草剂用量二因子为决策变量,对稗草的抑制率为目标函数,研究土壤湿度对三氮苯类除草剂药效的影响。结果表明,适当的土壤水分是三氮苯类除草剂发挥药效的重要因素,药效随土壤湿度的提高而提高。不同的土壤湿度对不同除草剂药效影响各异,高湿条件下,湿度差异对药效影响大小依次为嗪草酮、西草净、扑草净、莠去津,低湿条件下则相反。除草剂用量与土壤湿度存在最佳发挥药效的组合。     

Genetic diversity and historic introgression in German Angler and Red Dual Purpose cattle and possibilities to reverse introgression

Recovering native uniqueness has major importance for breeds with historic introgression. The aim of the study was to estimate population genetic parameters for two local red cattle breeds from Northern Germany and to study possibilities to reverse introgression. Genealogical information consisted of 90,783 individuals for German Angler and 187,255 individuals for Red Dual-Purpose cattle breed, with additional information on sex, born, breed, status, and conventional breeding values. It is concluded that the native genetic contribution could be included as an additional trait in the total merit index in order to recover a part of the native genetic background. Native contributions should be estimated in the long term from marker data in order to account for Mendelian sampling. The maintenance of a sufficient genetic diversity of native alleles can be achieved by an advanced OCS with appropriate constraints.     

Integration of pharmacokinetic–pharmacodynamic for dose optimization of doxycycline against Haemophilus parasuis in pigs

The aims of this study were to establish optimal doses of doxycycline (dox) against Haemophilus parasuis on the basis of pharmacokinetic–pharmacodynamic (PK‐PD) integration modeling. The infected model was established by intranasal inoculation of organism in pigs and confirmed by clinical signs, blood biochemistry, and microscopic examinations. The recommended dose (20 mg/kg b.w.) was administered in pigs through intramuscular routes for PK studies. The area under the concentration 0‐ to 24‐hr curve (AUC_0–24), elimination half‐life (T_½ke), and mean residence time (MRT) of dox in healthy and H. parasuis‐infected pigs were 55.51 ± 5.72 versus 57.10 ± 4.89 μg·hr/ml, 8.28 ± 0.91 versus 9.80 ± 2.38 hr, and 8.43 ± 0.27 versus 8.79 ± 0.18 hr, respectively. The minimal inhibitory concentration (MIC) of dox against 40 H. parasuis isolates was conducted through broth microdilution method, the corresponding MIC₅₀ and MIC₉₀ were 0.25 and 1 μg/ml, respectively. The Ex vivo growth inhibition data suggested that dox exhibited a concentration‐dependent killing mechanism. Based on the observed AUC_24 hr/MIC values by modeling PK‐PD data in H. parasuis‐infected pigs, the doses predicted to obtain bacteriostatic, bactericidal, and elimination effects for H. parasuis over 24 hr were 5.25, 8.55, and 10.37 mg/kg for the 50% target attainment rate (TAR), and 7.26, 13.82, and 18.17 mg/kg for 90% TAR, respectively. This study provided a more optimized alternative for clinical use and demonstrated that the dosage 20 mg/kg of dox by intramuscular administration could have an effective bactericidal activity against H. parasuis.     

基于贡献度随机森林模型的公司债信用风险实证分析

运用贡献度随机森林方法（CRF）方法探讨公司债财务指标比率与其违约率的关系.运用连续属性离散化方法（OB）进行财务指标最优降维；运用WOE变换进行模型变量约简.研究表明，CRF模型的分类性能显著优于其他模型，测试集评估总体正确率达90.47%，AUC统计量、AR比率及K-S值分别提升了2.6%、7.6%、4.38%，变量贡献度量化了各财务指标对违约率影响，为诠释随机森林预测机制提供了依据.     

遮穗和去颖下燕麦穗部特征变化和穗部光合贡献率估算

随着探索提高植物整体光合能力相关研究的不断开展，麦类作物穗部器官等植物非叶绿色器官光合潜力挖掘逐渐得到关注。本研究在成都平原秋播美达、贝勒、莫尼卡、摄政王、泰克和甜燕60等6个品种燕麦，设置遮穗、去颖2个试验处理，比较分析了各品种间穗部特征、穗部光合贡献率、颖片光合贡献率和茎光合物质转移率等差异。结果表明，燕麦穗部器官光合贡献率为28.56%～49.05%，其中甜燕60最高；6个品种燕麦的颖片光合贡献率为11.03%～36.88%，茎光合物质转移率为6.65%～35.81%。燕麦穗部器官对籽实增重表现了较高的光合贡献，当燕麦穗部器官光合受到限制时，燕麦单粒种子重和单穗种子数显著降低，尤其是影响双粒小穗数。     

淮安区水稻测土配方施肥配方校正与示范对比试验报告

为验证肥料配方的准确性,发挥配方肥料施用的最大效益。通过田间校验,示范对比测土配方施肥的增产效果,进一步验证并完善淮安区的肥料配方,优化测土配方施肥技术参数。