夏玉米产量时空变化及气候年型分析

定量分析夏玉米同一品种产量及产量构成要素时空变化,探讨造成产量时空差异的气候年型组合变化特征。基于2004～2013年夏玉米种植区郑单958多点田间试验数据分析表明,夏玉米区域平均产量为9 055 kg/hm~2,年际差为1 635 kg/hm~2,变幅为18.1%;地点差4 258 kg/hm~2,变幅为47.1%。夏玉米区域平均千粒重为313 g,年际变幅为13.1%;地点变幅为27.8%。夏玉米区域平均穗粒数为479,年际变幅为18.0%,地点变幅为38.7%。千粒重的增加导致夏玉米产量显著增加。穗粒数显著降低和时空差异大是造成产量波动和时空差异变幅大的主要原因。夏玉米产量和产量构成要素,低产点受各气候要素变化的影响显著;平产点受温度和日最高温度大于33℃的天数影响显著;高产点受降水影响显著。     

Evolution of spatial structure patterns of city networks in the Yangtze River Economic Belt from the perspective of corporate pledge linkage

The pledge of stock rights is a method for measuring the external horizontal connections of enterprises, which is more suitable to represent the city network compared with the vertical connections of enterprises. Meanwhile, it is greatly significant to express the relationships of regional spaces. The paper characterizes and explores the evolution of urban spatial structure with complex network research methods to enrich the relevant works on city networks in the Yangtze River Economic Belt from 2011 to 2017. The results are as follows: First, from 2011 to 2017, the pledge of stock rights among cities was enhanced significantly, and the trend of the city networks' characteristics become strengthened and more complicated. Second, cities in the Yangtze River Delta have relatively high connection values, however, cities in the western area are holding peripheral positions within the city network. Third, due to the advantages of economic agglomeration and radiation, the provincial capital have become the core nodes in the city network. Fourth, Shanghai, Hangzhou, and Nanjing have dominant positions within city networks in the Yangtze River Economic Belt. Particularly, Shanghai, as one of the leading financial centers in China, has a growing influence on other cities and gradually evolved into a regional growth pole city and the first core city.     

Effects and mechanisms of rural E-commerce clusters on households' entrepreneurship behavior in China

The vigorous development of rural E-commerce reveals a powerful pattern of economic clustering. Recently, many Taobao Villages have formed in more than 80% of the provinces in rural China, and increasingly households are using E-commerce for entrepreneurial innovation in Taobao Villages. However, the effect and mechanism of the Taobao Village model on households' entrepreneurship behavior remain unclear. Using survey data and structural equation modeling, we analyzed the factors of households' entrepreneurship behavior and investigated the mechanism of rural E-commerce clustering on the households' entrepreneurship behavior in Taobao Villages. The results show that: (1) rural E-commerce clusters stimulated entrepreneurial enthusiasm and increased entrepreneurial behavior; (2) local resource endowment, entrepreneurial atmosphere and culture, threshold for entrepreneurship, and demonstrative leadership had significant positive effects on households' entrepreneurship behavior; (3) external environmental support, including government, and external business environment support had significant positive effects on E-commerce development. All these results indicate that rural E-commerce clusters promote households' entrepreneurship behavior.     

探究姜和大蒜粗提取液对甘蓝枯萎病菌的抑制作用

研究旨在了解不同浓度姜和大蒜粗提取液对甘蓝枯萎病菌的抑制效果及对菌丝形态结构的影响,以此初步获得最适合的抑制病原菌的植物粗提取液浓度。以姜和大蒜粗提取液为供试材料,测定不同浓度2种粗提取液对甘蓝枯萎病菌尖孢镰刀菌的生长情况、孢子浓度、孢子萌发率及菌丝结构的影响。结果表明,2种粗提取液均能抑制并降低尖孢镰刀菌的生长速率、孢子浓度和孢子萌发率,且大蒜粗提取液比姜粗提取液抑制效果更显著,在低浓度下对菌丝形态结构的影响也比姜粗提取液明显,大蒜粗提取液在各浓度下与对照相比均达极显著差异,且大蒜浓度为0.4 g/mL时对尖孢镰刀菌孢子萌发率抑制达100%。该试验证实大蒜对甘蓝枯萎病菌有极显著抑制作用,为使用间种或轮作大蒜进行田间防治甘蓝枯萎病菌提供了参考。     

如何提高缉毒犬的实际工作能力

缉毒犬对各种毒品气味的分辨能力,即一头受训犬能够在各种复杂的环境中,准确地从烟、酒、食物、糖、茶、化妆品、药材以及化学物品等干扰气味中分辨出某种毒品气味,并反应正确。目前,有些地方的缉毒犬只是对单一毒品气味进行了训练：并且考虑在更为复杂的环境下的训练,即模拟训练。这种训练接近实战,要求带犬民警充分考虑到实战现场的复杂性,并以此为标准,对模拟训练中的三种形式进行合理的布局。     

玉米新品种沧玉76示范试验与栽培技术

沧玉76是河北沧玉种业科技有限公司于2010年采用C1058×CB128选育而成的玉米品种,多点高产示范平均产量均在10000 kg/hm²以上。2017年的适应性研究与示范试验中,产量为11831.0 kg/hm²,较对照郑单958增产10.33%。从播种、水肥管理、病虫草害防治、收获等方面提出了沧玉76高产栽培技术。