关于骆驼抗逆性的思考

从探险家发现南极鱼到科学家在南极鱼体内找到抗冷冻蛋白,联想到如何挖掘骆驼所具有的抗逆性。围绕骆驼特有的耐热、耐渴、耐寒、耐饿、耐粗饲料等生物学特性,对驼产业的开发与利用提出了新的思路。     

螺旋式输送装置参数优化研究

为了提高农业纤维物料螺旋式输送装置的输送性能,降低输送功耗,提高生产率,利用MATLAB软件对比功耗数学模型进行单变量优化分析,并结合试验验证了理论分析的一致性。试验结果表明:螺旋式输送装置输送性能最佳的取值范围是:喂入量30～70 kg/min、螺距300～355 mm、螺旋轴转速97～137 r/min。以比功耗作为输送性能评价指标,采用3因素3水平的Box-Benhnken响应面分析法进行参数优化试验,得到了影响比功耗各因素的主次顺序:喂入量、螺距、螺旋轴转速。以比功耗最小为优化目标,利用Design-expert的优化模块对试验结果进行分析,确定出各因素对指标影响的最佳参数组合:螺距335 mm、螺旋轴转速117 r/min、喂入量30 kg/min,输送性能优化后比优化前提高了8%,上述成果满足预期设计目标,可为螺旋式输送装置的参数优化和结构改进提供一定的参考和指导。     

中草药提取物对蔬菜两种采后病原真菌的抑菌活性研究

以灰葡萄孢菌和链格孢菌为供试病菌,采用生长速率法和培养板连续稀释法在离体条件下研究了木香、决明子等16种中草药提取物抑菌活性,对其效果较好的中草药提取物最小抑菌浓度(MIC)和最小杀菌浓度(MFC)进行了初步确定。试验结果显示,北豆根与黄柏在质量浓度为10.0mg/mL时,对两种病原真菌菌丝生长的抑制率均高于60%。它们对灰葡萄孢菌的最小抑菌浓度MIC依次是12.5,25mg/mL,最小杀菌浓度浓度MFC分别为:25,50mg/mL;对链格孢菌的MIC分别是6.25,12.5mg/mL,MFC都高于MIC两倍,分别是12.5,25mg/mL。     

Research advances of SAR remote sensing for agriculture applications: A review

Synthetic aperture radar (SAR) is an effective and important technique in monitoring crop and other agricultural targets because its quality does not depend on weather conditions. SAR is sensitive to the geometrical structures and dielectric properties of the targets and has a certain penetration ability to some agricultural targets. The capabilities of SAR for agriculture applications can be organized into three main categories: crop identification and crop planting area statistics, crop and cropland parameter extraction, and crop yield estimation. According to the above concepts, this paper systematically analyses the recent progresses, existing problems and future directions in SAR agricultural remote sensing. In recent years, with the remarkable progresses in SAR remote sensing systems, the available SAR data sources have been greatly enriched. The accuracies of the crop classification and parameter extraction by SAR data have been improved progressively. But the development of modern agriculture has put forwarded higher requirements for SAR remote sensing. For instance, the spatial resolution and revisiting cycle of the SAR sensors, the accuracy of crop classification, the whole phenological period monitoring of crop growth status, the soil moisture inversion under the condition of high vegetation coverage, the integrations of SAR remote sensing retrieval information with hydrological models and/or crop growth models, and so on, still need to be improved. In the future, the joint use of optical and SAR remote sensing data, the application of multi-band multi-dimensional SAR, the precise and high efficient modeling of electromagnetic scattering and parameter extraction of crop and farmland composite scene, the development of light and small SAR systems like those onboard unmanned aerial vehicles and their applications will be active research areas in agriculture remote sensing. This paper concludes that SAR remote sensing has great potential and will play a more significant role in the various fields of agricultural remote sensing.     

不同类型城市绿地空气质量研究

为合理规划城市绿地,有益于人们户外活动,研究了不同类型城市绿地空气负离子浓度的日变化,不同类型城市绿地空气负离子浓度、温度、湿度、可吸入颗粒物、氮氧化物、二氧化硫、噪声的差异。结果表明:空气负离子浓度日变化均较明显,不同类型绿地空气负离子浓度、温度、湿度存在显著差异,生物群落越丰富、树龄越大、植被郁闭度越高则空气负离子浓度、湿度越高,温度越低;由枝叶茂盛的高大乔木组成的林地,其空气负离子水平和空气质量较好。空气可吸入颗粒物、氮氧化物、二氧化硫及噪声污染与植被有一定的相关性,相关关系不显著。       

科尔沁沙地系统诊断及其可持续发展

应用系统诊断方法,对科尔沁沙地系统的特征、存在问题及成因进行了分析,认为沙地系统衰退最根本的原因是政策、管理体制的不合理及科技人才的短缺;引起土地沙漠化的直接原因为急剧增长的人口、严重短缺的农村牧区燃料资源以及农业科技意识的淡薄.在此基础上还提出了沙地系统可持续发展的战略对策.     

Populations of inshore serranids across the Canarian Archipelago: Relationships with human pressure and implications for conservation

We investigated spatio-temporal variability in the abundances and biomasses of four species of inshore serranids (the dusky grouper Ephinephelus marginatus, the island grouper Mycteroperca fusca, the painted comber Serranus scriba, and the blacktail comber S. atricauda) throughout the Canarian Archipelago (central-east Atlantic Ocean) with underwater visual transects. By means of a multiscaled sampling design spanning three orders of magnitude of spatial variability (from 10 s of meters among replicated 100 m² transects to 100 s of kilometres among islands) and four sampling periods, we related differences in the distributions of serranids to differences in the degree of human pressure, such as fishing intensity and human population. Differences in human pressure among islands provide the most parsimonious explanation for many of the consistent inter-island differences in the abundance and biomass of the analyzed species. Larger-bodied serranids (E. marginatus and M. fusca) are more vulnerable than the smaller species (S. scriba and S. atricauda). In fact, the larger, more vulnerable species have been almost completely extirpated from the most intensely fished islands. Our results show that the larger groupers have been overexploited throughout the Canary Islands, and highlight the urgent need for stringent management measures and better control of littoral reef fish resources.     

Hemagglutinins in vegetative tissues of Bengal gram

Hemagglutinating activity was identified in the roots and vegetative tissues of Bengal gram using rabbit erythrocytes. The activity in the roots appears to be similar to that of the seeds in respect to their sugar inhibition property. Seed and root extracts were found to have fetuin inhibitory agglutinating activity, whereas cotyledons showed different sugar specificity. However, 7-day cotyledons and roots from 3 and 7-day plants were also found to have galactose and N-acetyl-D-galactosamine inhibitory activity. Protein profile in different tissues during their developmental stages was analyzed by SDS-PAGE. A major band at 66 kDa was common to all tissues at different stages of their development except 3-day cotyledons where 2 major bands at 22 kDa and 74 kDa were observed. Two prominent bands at 74 kDa and 86 kDa were found along with 60 kDa protein in 3-day old roots whereas a major band at 33 kDa was found in 15-day old roots. Total protein content and specific activity of hemagglutinin were measured. Increase in specific activity with lower protein content was observed in cotyledons of 15-day old plant. Specific activity was eight times higher in the roots and four times more in leaf tissues of 7-day old plants in comparison to 15-day old plants. Stems also showed a significant increase of specific activity (p = 0.013) in 7-day old plants without any significant alteration in the protein content.     

科尔沁地区的垦殖与荒漠化

不合理的开垦是我国北方土地沙质荒漠化的主要原因,北方农牧交错带45%的退化土地属这一类型.垦殖也是过去科尔沁地区沙地几度活化的主导因素.人类历史时期以来,科尔沁地区沙地的活化和稳定、垦殖期和弃耕期的环境特征的变化,再一次证明了这一点.     

利用高等数学推导边际分析在经济学中的应用

本文从高等数学的基本理论导数的概念出发，引出了经济管理学中重要的概念边际函数，通过介绍经济科学中常用的函数及大量的实例，探讨了高等数学在经济管理学中的应用，给出了解决这些问题的一般方法。